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Sample records for human c-myc gene

  1. Nucleotide sequence of the human N-myc gene

    International Nuclear Information System (INIS)

    Stanton, L.W.; Schwab, M.; Bishop, J.M.

    1986-01-01

    Human neuroblastomas frequently display amplification and augmented expression of a gene known as N-myc because of its similarity to the protooncogene c-myc. It has therefore been proposed that N-myc is itself a protooncogene, and subsequent tests have shown that N-myc and c-myc have similar biological activities in cell culture. The authors have now detailed the kinship between N-myc and c-myc by determining the nucleotide sequence of human N-myc and deducing the amino acid sequence of the protein encoded by the gene. The topography of N-myc is strikingly similar to that of c-myc: both genes contain three exons of similar lengths; the coding elements of both genes are located in the second and third exons; and both genes have unusually long 5' untranslated regions in their mRNAs, with features that raise the possibility that expression of the genes may be subject to similar controls of translation. The resemblance between the proteins encoded by N-myc and c-myc sustains previous suspicions that the genes encode related functions

  2. c-Myc-Dependent Cell Competition in Human Cancer Cells.

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    Patel, Manish S; Shah, Heta S; Shrivastava, Neeta

    2017-07-01

    Cell Competition is an interaction between cells for existence in heterogeneous cell populations of multicellular organisms. This phenomenon is involved in initiation and progression of cancer where heterogeneous cell populations compete directly or indirectly for the survival of the fittest based on differential gene expression. In Drosophila, cells having lower dMyc expression are eliminated by cell competition through apoptosis when present in the milieu of cells having higher dMyc expression. Thus, we designed a study to develop c-Myc (human homolog) dependent in vitro cell competition model of human cancer cells. Cells with higher c-Myc were transfected with c-myc shRNA to prepare cells with lower c-Myc and then co-cultured with the same type of cells having a higher c-Myc in equal ratio. Cells with lower c-Myc showed a significant decrease in numbers when compared with higher c-Myc cells, suggesting "loser" and "winner" status of cells, respectively. During microscopy, engulfment of loser cells by winner cells was observed with higher expression of JNK in loser cells. Furthermore, elimination of loser cells was prevented significantly, when co-cultured cells were treated with the JNK (apoptosis) inhibitor. Above results indicate elimination of loser cells in the presence of winner cells by c-Myc-dependent mechanisms of cell competition in human cancer cells. This could be an important mechanism in human tumors where normal cells are eliminated by c-Myc-overexpressed tumor cells. J. Cell. Biochem. 118: 1782-1791, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  3. Evolutionarily conserved regions of the human c-myc protein can be uncoupled from transforming activity

    International Nuclear Information System (INIS)

    Sarid, J.; Halazonetis, T.D.; Murphy, W.; Leder, P.

    1987-01-01

    The myc family of oncogenes contains coding sequences that have been preserved in different species for over 400 million years. This conservation (which implies functional selection) is broadly represented throughout the C-terminal portion of the human c-myc protein but is largely restricted to three cluster of amino acid sequences in the N-terminal region. The authors have examined the role that the latter three regions of the c-myc protein might play in the transforming function of the c-myc gene. Several mutations, deletions and frameshifts, were introduced into the c-myc gene, and these mutant genes were tested for their ability to collaborate with the EJ-ras oncogene to transform rat embryo fibroblasts. Complete elimination of the first two N-terminal conserved segments abolished transforming activity. In contrast, genes altered in a portion of the second or the entire third conserved segment retained their transforming activity. Thus, the latter two segments are not required for the transformation process, suggesting that they serve another function related only to the normal expression of the c-myc gene

  4. c-Myc activates BRCA1 gene expression through distal promoter elements in breast cancer cells

    International Nuclear Information System (INIS)

    Chen, Yinghua; Xu, Jinhua; Borowicz, Stanley; Collins, Cindy; Huo, Dezheng; Olopade, Olufunmilayo I

    2011-01-01

    The BRCA1 gene plays an important role in the maintenance of genomic stability. BRCA1 inactivation contributes to breast cancer tumorigenesis. An increasing number of transcription factors have been shown to regulate BRCA1 expression. c-Myc can act as a transcriptional activator, regulating up to 15% of all genes in the human genome and results from a high throughput screen suggest that BRCA1 is one of its targets. In this report, we used cultured breast cancer cells to examine the mechanisms of transcriptional activation of BRCA1 by c-Myc. c-Myc was depleted using c-Myc-specific siRNAs in cultured breast cancer cells. BRCA1 mRNA expression and BRCA1 protein expression were determined by quantitative RT-PCR and western blot, respectively and BRCA1 promoter activities were examined under these conditions. DNA sequence analysis was conducted to search for high similarity to E boxes in the BRCA1 promoter region. The association of c-Myc with the BRCA1 promoter in vivo was tested by a chromatin immunoprecipitation assay. We investigated the function of the c-Myc binding site in the BRCA1 promoter region by a promoter assay with nucleotide substitutions in the putative E boxes. BRCA1-dependent DNA repair activities were measured by a GFP-reporter assay. Depletion of c-Myc was found to be correlated with reduced expression levels of BRCA1 mRNA and BRCA1 protein. Depletion of c-Myc decreased BRCA1 promoter activity, while ectopically expressed c-Myc increased BRCA1 promoter activity. In the distal BRCA1 promoter, DNA sequence analysis revealed two tandem clusters with high similarity, and each cluster contained a possible c-Myc binding site. c-Myc bound to these regions in vivo. Nucleotide substitutions in the c-Myc binding sites in these regions abrogated c-Myc-dependent promoter activation. Furthermore, breast cancer cells with reduced BRCA1 expression due to depletion of c-Myc exhibited impaired DNA repair activity. The distal BRCA1 promoter region is associated with c-Myc

  5. Human small-cell lung cancers show amplification and expression of the N-myc gene

    International Nuclear Information System (INIS)

    Nau, M.M.; Brooks, B.J. Jr.; Carney, D.N.; Gazdar, A.F.; Battey, J.F.; Sausville, E.A.; Minna, J.D.

    1986-01-01

    The authors have found that 6 of 31 independently derived human small-cell lung cancer (SCLC) cell lines have 5- to 170-fold amplified N-myc gene sequences. The amplification is seen with probes from two separate exons of N-myc, which are homologous to either the second or the third exon of the c-myc gene. Amplified N-myc sequences were found in a tumor cell line started prior to chemotherapy, in SCLC tumor samples harvested directly from tumor metastases at autopsy, and from a resected primary lung cancer. Several N-myc-amplified tumor cell lines also exhibited N-myc hybridizing fragments not in the germ-line position. In one patient's tumor, an additional amplitifed N-myc DNA fragment was observed and this fragment was heterogeneously distributed in liver metastases. In contrast to SCLC with neuroendocrine properties, no non-small-cell lung cancer lines examined were found to have N-myc amplification. Fragments encoding two N-myc exons also detect increased amounts of a 3.1-kilobase N-myc mRNA in N-myc-amplified SCLC lines and in one cell line that does not show N-myc gene amplification. Both DNA and RNA hybridization experiments, using a 32 P-labelled restriction probe, show that in any one SCLC cell line, only one myc-related gene is amplified and expressed. They conclude that N-myc amplification is both common and potentially significant in the tumorigenesis or tumor progression of SCLC

  6. Overexpression and amplification of the c-myc gene in mouse tumors induced by chemical and radiations

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    Niwa, Ohtsura; Enoki, Yoshitaka; Yokoro, Kenjiro

    1989-03-01

    We examined expression of the c-myc gene by the dot blot hybridization of total cellular RNA from mouse primary tumors induced by chemicals and radiations. Expression of the c-myc gene was found to be elevated in 69 cases among 177 independently induced tumors of 12 different types. DNA from tumors overexpressing the myc gene was analyzed by Southern blotting. No case of rearrangement was detected. However, amplification of the c-myc gene was found in 7 cases of primary sarcomas. These included 4 cases out of 24 methylcholanthrene-induced sarcomas and 3 cases out of 7 /alpha/-tocopherol-induced sacromas. We also analyzed 8 cases of sarcomas induced by radiations, but could not find changes in the gene structure of the c-myc gene. Thus, our data indicate tumor type specificity and agent specificity of c-myc gene amplification. (author).

  7. Immortalization of human neural stem cells with the c-myc mutant T58A.

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    Lidia De Filippis

    Full Text Available Human neural stem cells (hNSC represent an essential source of renewable brain cells for both experimental studies and cell replacement therapies. Their relatively slow rate of proliferation and physiological senescence in culture make their use cumbersome under some experimental and pre-clinical settings. The immortalization of hNSC with the v-myc gene (v-IhNSC has been shown to generate stem cells endowed with enhanced proliferative capacity, which greatly facilitates the study of hNSCs, both in vitro and in vivo. Despite the excellent safety properties displayed by v-IhNSCs--which do not transform in vitro and are not tumorigenic in vivo--the v-myc gene contains several mutations and recombination elements, whose role(s and effects remains to be elucidated, yielding unresolved safety concerns. To address this issue, we used a c-myc T58A retroviral vector to establish an immortal cell line (T-IhNSC from the same hNSCs used to generate the original v-IhNSCs and compared their characteristics with the latter, with hNSC and with hNSC immortalized using c-myc wt (c-IhNSC. T-IhNSCs displayed an enhanced self-renewal ability, with their proliferative capacity and clonogenic potential being remarkably comparable to those of v-IhNSC and higher than wild type hNSCs and c-IhNSCs. Upon growth factors removal, T-IhNSC promptly gave rise to well-differentiated neurons, astrocytes and most importantly, to a heretofore undocumented high percentage of human oligodendrocytes (up to 23%. Persistent growth-factor dependence, steady functional properties, lack of ability to generate colonies in soft-agar colony-forming assay and to establish tumors upon orthotopic transplantation, point to the fact that immortalization by c-myc T58A does not bring about tumorigenicity in hNSCs. Hence, this work describes a novel and continuous cell line of immortalized human multipotent neural stem cells, in which the immortalizing agent is represented by a single gene which, in

  8. Aberrant immunoglobulin and c-myc gene rearrangements in patients with nonmalignant monoclonal cryoglobulinemia

    International Nuclear Information System (INIS)

    Perl, A.; Wang, N.; Williams, J.M.; Hunt, M.J.; Rosenfeld, S.I.; Condemi, J.J.; Packman, C.H.; Abraham, G.N.

    1987-01-01

    The status of the immunoglobulin (Ig) genes was investigated in patients with idiopathic nonmalignant monoclonal IgG cryoglobulinemia (NCG). In NCG, monoclonal antibodies are synthesized at an accelerated rate by nonmalignant B lymphocytes. In order to determine whether this high production rate is related to a clonal B cell expansion, the rearrangement of the Ig genes was investigated by Southern blot analysis of genomic, 32 P-labelled, DNA extracted from the peripheral blood lymphocytes of four NCG patients. In three of four (VI, BR, and CH) clonal expansion of B cells was detected using probes specific for the genes. BamHI digestion of DNA from VI and BR produced three rearranged fragments which cohybridized with two of the probes. This finding suggested the presence of additional nonsecretory B cell clones and/or disruption of the gene segments spanned by and detected with the probes. In addition, the possibility of aberrant gene rearrangements was supported by noting the alteration of the c-myc gene locus in genomic DNA from peripheral blood leukocytes of VI and CH. Northern blot analysis of RNA isolated from peripheral blood B cells of VI and CH demonstrated aberrant transcripts of the c-myc gene, showing an active role of the altered c-myc locus. Detection of c-myc rearrangement in NCG patients clearly shows that this event may not be a final step in malignant B cell transformation

  9. c-myc overexpression causes anaplasia in medulloblastoma.

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    Stearns, Duncan; Chaudhry, Aneeka; Abel, Ty W; Burger, Peter C; Dang, Chi V; Eberhart, Charles G

    2006-01-15

    Both anaplasia and increased c-myc gene expression have been shown to be negative prognostic indicators for survival in medulloblastoma patients. myc gene amplification has been identified in many large cell/anaplastic medulloblastoma, but no causative link between c-myc and anaplastic changes has been established. To address this, we stably overexpressed c-myc in two medulloblastoma cell lines, DAOY and UW228, and examined the changes in growth characteristics. When analyzed in vitro, cell lines with increased levels of c-myc had higher rates of growth and apoptosis as well as significantly improved ability to form colonies in soft agar compared with control. When injected s.c. into nu/nu mice, flank xenograft tumors with high levels of c-myc in DAOY cell line background were 75% larger than those derived from control. Overexpression of c-myc was required for tumor formation by UW228 cells. Most remarkably, the histopathology of the Myc tumors was severely anaplastic, with large areas of necrosis/apoptosis, increased nuclear size, and macronucleoli. Indices of proliferation and apoptosis were also significantly higher in Myc xenografts. Thus, c-myc seems to play a causal role in inducing anaplasia in medulloblastoma. Because anaplastic changes are often observed in recurrent medulloblastoma, we propose that c-myc dysregulation is involved in the progression of these malignant embryonal neoplasms.

  10. AP-2α Inhibits c-MYC Induced Oxidative Stress and Apoptosis in HaCaT Human Keratinocytes

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    Lei Yu

    2009-01-01

    AP-2 may have a direct effect on the c-myc gene. Chromatin immunoprecipitation assays demonstrated that AP-2 proteins bound to a cluster of AP-2 binding sites located within a 2 kb upstream regulatory region of c-myc These results suggest that the negative regulation of AP-2 on c-MYC activity was achieved through binding of AP-2 protein to the c-myc gene. The effects of AP-2 on c-MYC induced ROS accumulation and apoptosis in epidermal keratinocytes are likely to play an important role in cell growth, differentiation and carcinogenesis of the skin.

  11. Nuclear localization of phosphorylated c-Myc protein in human tumor cells.

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    C. Soldani

    2010-05-01

    Full Text Available Using immunocytochemical techniques at light and electron microscopy, we analysed the distribution of phosphorylated c-Myc in actively proliferating human HeLa cells. The distribution pattern of c-Myc was also compared with those of other ribonucleoprotein (RNP-containing components (PANA, hnRNP-core proteins, fibrillarin or RNP-associated nuclear proteins (SC-35 splicing factor. Our results provide the first evidence that phosphorylated c-Myc accumulates in the nucleus of tumor cells, where it colocalizes with fibrillarin, both in the nucleolus and in extranucleolar structures.

  12. Transduction of Oct6 or Oct9 gene concomitant with Myc family gene induced osteoblast-like phenotypic conversion in normal human fibroblasts

    International Nuclear Information System (INIS)

    Mizoshiri, N.; Kishida, T.; Yamamoto, K.; Shirai, T.; Terauchi, R.; Tsuchida, S.; Mori, Y.; Ejima, A.; Sato, Y.; Arai, Y.; Fujiwara, H.; Yamamoto, T.; Kanamura, N.; Mazda, O.; Kubo, T.

    2015-01-01

    Introduction: Osteoblasts play essential roles in bone formation and regeneration, while they have low proliferation potential. Recently we established a procedure to directly convert human fibroblasts into osteoblasts (dOBs). Transduction of Runx2 (R), Osterix (X), Oct3/4 (O) and L-myc (L) genes followed by culturing under osteogenic conditions induced normal human fibroblasts to express osteoblast-specific genes and produce calcified bone matrix both in vitro and in vivo Intriguingly, a combination of only two factors, Oct3/4 and L-myc, significantly induced osteoblast-like phenotype in fibroblasts, but the mechanisms underlying the direct conversion remains to be unveiled. Materials and Methods: We examined which Oct family genes and Myc family genes are capable of inducing osteoblast-like phenotypic conversion. Results: As result Oct3/4, Oct6 and Oct9, among other Oct family members, had the capability, while N-myc was the most effective Myc family gene. The Oct9 plus N-myc was the best combination to induce direct conversion of human fibroblasts into osteoblast-like cells. Discussion: The present findings may greatly contribute to the elucidation of the roles of the Oct and Myc proteins in osteoblast direct reprogramming. The results may also lead to establishment of novel regenerative therapy for various bone resorption diseases. - Highlights: • Introducing L-myc in a combination with either Oct3/4, Oct6 or Oct9 enables the conversion of fibroblasts to osteoblasts. • A combination of L-myc with Oct3/4 or Oct9 can induce the cells to a phenotype closer to normal osteoblasts. • N-myc was considered the most appropriate Myc family gene for induction of osteoblast-like phenotype in fibroblasts. • The combination of Oct9 plus N-myc has the strongest capability of inducing osteoblast-like phenotype.

  13. Transduction of Oct6 or Oct9 gene concomitant with Myc family gene induced osteoblast-like phenotypic conversion in normal human fibroblasts

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    Mizoshiri, N. [Department of Immunology, Kyoto Prefectural University of Medicine, Kyoto (Japan); Department of Orthopaedics, Kyoto Prefectural University of Medicine, Kyoto (Japan); Kishida, T. [Department of Immunology, Kyoto Prefectural University of Medicine, Kyoto (Japan); Yamamoto, K. [Department of Immunology, Kyoto Prefectural University of Medicine, Kyoto (Japan); Department of Dental Medicine, Kyoto Prefectural University of Medicine, Kyoto (Japan); Shirai, T.; Terauchi, R.; Tsuchida, S. [Department of Orthopaedics, Kyoto Prefectural University of Medicine, Kyoto (Japan); Mori, Y. [Department of Immunology, Kyoto Prefectural University of Medicine, Kyoto (Japan); Department of Orthopaedics, Kyoto Prefectural University of Medicine, Kyoto (Japan); Ejima, A. [Department of Immunology, Kyoto Prefectural University of Medicine, Kyoto (Japan); Sato, Y. [Department of Immunology, Kyoto Prefectural University of Medicine, Kyoto (Japan); Department of Dental Medicine, Kyoto Prefectural University of Medicine, Kyoto (Japan); Arai, Y.; Fujiwara, H. [Department of Orthopaedics, Kyoto Prefectural University of Medicine, Kyoto (Japan); Yamamoto, T.; Kanamura, N. [Department of Dental Medicine, Kyoto Prefectural University of Medicine, Kyoto (Japan); Mazda, O., E-mail: mazda@koto.kpu-m.ac.jp [Department of Immunology, Kyoto Prefectural University of Medicine, Kyoto (Japan); Kubo, T. [Department of Orthopaedics, Kyoto Prefectural University of Medicine, Kyoto (Japan)

    2015-11-27

    Introduction: Osteoblasts play essential roles in bone formation and regeneration, while they have low proliferation potential. Recently we established a procedure to directly convert human fibroblasts into osteoblasts (dOBs). Transduction of Runx2 (R), Osterix (X), Oct3/4 (O) and L-myc (L) genes followed by culturing under osteogenic conditions induced normal human fibroblasts to express osteoblast-specific genes and produce calcified bone matrix both in vitro and in vivo Intriguingly, a combination of only two factors, Oct3/4 and L-myc, significantly induced osteoblast-like phenotype in fibroblasts, but the mechanisms underlying the direct conversion remains to be unveiled. Materials and Methods: We examined which Oct family genes and Myc family genes are capable of inducing osteoblast-like phenotypic conversion. Results: As result Oct3/4, Oct6 and Oct9, among other Oct family members, had the capability, while N-myc was the most effective Myc family gene. The Oct9 plus N-myc was the best combination to induce direct conversion of human fibroblasts into osteoblast-like cells. Discussion: The present findings may greatly contribute to the elucidation of the roles of the Oct and Myc proteins in osteoblast direct reprogramming. The results may also lead to establishment of novel regenerative therapy for various bone resorption diseases. - Highlights: • Introducing L-myc in a combination with either Oct3/4, Oct6 or Oct9 enables the conversion of fibroblasts to osteoblasts. • A combination of L-myc with Oct3/4 or Oct9 can induce the cells to a phenotype closer to normal osteoblasts. • N-myc was considered the most appropriate Myc family gene for induction of osteoblast-like phenotype in fibroblasts. • The combination of Oct9 plus N-myc has the strongest capability of inducing osteoblast-like phenotype.

  14. c-myc Amplification Is Frequent in Esophageal Adenocarcinoma and Correlated with the Upregulation of VEGF-A Expression

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    Burkhard H.A. von Rahden

    2006-09-01

    Full Text Available BACKGROUND: Deregulation of c-myc plays a major role in the carcinogenesis of human malignancies. We investigated the amplification of the c-myc gene in a surgical series of Barrett cancers. METHODS: Primary resected esophageal (Barrett adenocarcinomas (n = 84 were investigated for c-myc amplification using chromogene in situ hybridization. Tumor samples were assembled in a tissue microarray. c-myc gene dosage was correlated with clinicopathologic parameters, including the survival and gene expression of cyclooxygenases (COX-1 and COX-2 and proangiogenic growth factors (VEGF-A and VEGF-C. RESULTS: The majority (70 of 84; 83.3% exhibited amplification of the c-myc gene. There were low-level amplifications in 63 (75.0% cases and high-level amplifications in 7 (8.3% cases. No amplification was found in 14 (16.7% cases. Tumors without c-myc amplification had lower VEGF-A, VEGF-C, and COX-2 expression levels than tumors with low-level and high-level c-myc amplification (statistically significant for VEGF-A; P = .0348. c-myc amplification was not correlated with clinicopathological parameters or survival. Only diffuse and mixed-type tumors, according to Lauren classification, exhibited c-myc amplifications more frequently (P = .0466. CONCLUSIONS: Amplifications of the c-myc gene are frequent in Barrett cancer. c-myc may be involved in the regulation of angiogenesis.

  15. Mechanism of estrogen activation of c-myc oncogene expression.

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    Dubik, D; Shiu, R P

    1992-08-01

    The estrogen receptor complex is a known trans-acting factor that regulates transcription of specific genes through an interaction with a specific estrogen-responsive cis-acting element (ERE). In previous studies we have shown that in estrogen-responsive human breast cancer cells estrogen rapidly activates c-myc expression. This activated expression occurs through enhanced transcription and does not require the synthesis of new protein intermediates; therefore, an ERE is present in the human c-myc gene regulatory region. To localize the ERE, constructs containing varying lengths of the c-myc 5'-flanking region ranging from -2327 to +25 (relative to the P1 promoter) placed adjacent to the chloramphenicol acetyl transferase reporter gene (CAT) were prepared. They were used in transient transfection studies in MCF-7 and HeLa cells co-transfected with an estrogen receptor expression vector. These studies reveal that all constructs containing the P2 promoter region exhibited estrogen-regulated CAT expression and that a 116-bp region upstream and encompassing the P2 TATA box is necessary for this activity. Analysis of this 116-bp region failed to identify a cis-acting element with sequences resembling the consensus ERE; however, co-transfection studies with mutant estrogen receptor expression vectors showed that the DNA-binding domain of the receptor is essential for estrogen-regulated CAT gene expression. We have also observed that anti-estrogen receptor complexes can weakly trans-activate from this 116-bp region but fail to do so from the ERE-containing ApoVLDLII-CAT construct. To explain these results we propose a new mechanism of estrogen trans-activation in the c-myc gene promoter.

  16. c-MYC amplification and c-myc protein expression in pancreatic acinar cell carcinomas. New insights into the molecular signature of these rare cancers.

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    La Rosa, Stefano; Bernasconi, Barbara; Vanoli, Alessandro; Sciarra, Amedeo; Notohara, Kenji; Albarello, Luca; Casnedi, Selenia; Billo, Paola; Zhang, Lizhi; Tibiletti, Maria Grazia; Sessa, Fausto

    2018-05-02

    The molecular alterations of pancreatic acinar cell carcinomas (ACCs) and mixed acinar-neuroendocrine carcinomas (MANECs) are not completely understood, and the possible role of c-MYC amplification in tumor development, progression, and prognosis is not known. We have investigated c-MYC gene amplification in a series of 35 ACCs and 4 MANECs to evaluate its frequency and a possible prognostic role. Gene amplification was investigated using interphasic fluorescence in situ hybridization analysis simultaneously hybridizing c-MYC and the centromere of chromosome 8 probes. Protein expression was immunohistochemically investigated using a specific monoclonal anti-c-myc antibody. Twenty cases had clones with different polysomies of chromosome 8 in absence of c-MYC amplification, and 5 cases had one amplified clone and other clones with chromosome 8 polysomy, while the remaining 14 cases were diploid for chromosome 8 and lacked c-MYC amplification. All MANECs showed c-MYC amplification and/or polysomy which were observed in 54% pure ACCs. Six cases (15.3%) showed nuclear immunoreactivity for c-myc, but only 4/39 cases showed simultaneous c-MYC amplification/polysomy and nuclear protein expression. c-myc immunoreactivity as well as c-MYC amplification and/or chromosome 8 polysomy was not statistically associated with prognosis. Our study demonstrates that a subset of ACCs shows c-MYC alterations including gene amplification and chromosome 8 polysomy. Although they are not associated with a different prognostic signature, the fact that these alterations are present in all MANECs suggests a role in the acinar-neuroendocrine differentiation possibly involved in the pathogenesis of MANECs.

  17. XPC Promotes Pluripotency of Human Dental Pulp Cells through Regulation of Oct-4/Sox2/c-Myc

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    Lu Liu

    2016-01-01

    Full Text Available Introduction. Xeroderma pigmentosum group C (XPC, essential component of multisubunit stem cell coactivator complex (SCC, functions as the critical factor modulating pluripotency and genome integrity through interaction with Oct-4/Sox2. However, its specific role in regulating pluripotency and multilineage differentiation of human dental pulp cells (DPCs remains unknown. Methods. To elucidate the functional role XPC played in pluripotency and multilineage differentiation of DPCs, expressions of XPC in DPCs with long-term culture were examined by real-time PCR and western blot. DPCs were transfected with lentiviral-mediated human XPC gene; then transfection rate was investigated by real-time PCR and western blot. Cell cycle, apoptosis, proliferation, senescence, multilineage differentiation, and expression of Oct-4/Sox2/c-Myc in transfected DPCs were examined. Results. XPC, Oct-4, Sox2, and c-Myc were downregulated at P7 compared with P3 in DPCs with long-term culture. XPC genes were upregulated in DPCs at P2 after transfection and maintained high expression level at P3 and P7. Cell proliferation, PI value, and telomerase activity were enhanced, whereas apoptosis was suppressed in transfected DPCs. Oct-4/Sox2/c-Myc were significantly upregulated, and multilineage differentiation in DPCs with XPC overexpression was enhanced after transfection. Conclusions. XPC plays an essential role in the modulation of pluripotency and multilineage differentiation of DPCs through regulation of Oct-4/Sox2/c-Myc.

  18. XPC Promotes Pluripotency of Human Dental Pulp Cells through Regulation of Oct-4/Sox2/c-Myc.

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    Liu, Lu; Peng, Zhengjun; Xu, Zhezhen; Wei, Xi

    2016-01-01

    Introduction. Xeroderma pigmentosum group C (XPC), essential component of multisubunit stem cell coactivator complex (SCC), functions as the critical factor modulating pluripotency and genome integrity through interaction with Oct-4/Sox2. However, its specific role in regulating pluripotency and multilineage differentiation of human dental pulp cells (DPCs) remains unknown. Methods. To elucidate the functional role XPC played in pluripotency and multilineage differentiation of DPCs, expressions of XPC in DPCs with long-term culture were examined by real-time PCR and western blot. DPCs were transfected with lentiviral-mediated human XPC gene; then transfection rate was investigated by real-time PCR and western blot. Cell cycle, apoptosis, proliferation, senescence, multilineage differentiation, and expression of Oct-4/Sox2/c-Myc in transfected DPCs were examined. Results. XPC, Oct-4, Sox2, and c-Myc were downregulated at P7 compared with P3 in DPCs with long-term culture. XPC genes were upregulated in DPCs at P2 after transfection and maintained high expression level at P3 and P7. Cell proliferation, PI value, and telomerase activity were enhanced, whereas apoptosis was suppressed in transfected DPCs. Oct-4/Sox2/c-Myc were significantly upregulated, and multilineage differentiation in DPCs with XPC overexpression was enhanced after transfection. Conclusions. XPC plays an essential role in the modulation of pluripotency and multilineage differentiation of DPCs through regulation of Oct-4/Sox2/c-Myc.

  19. Liver tumor formation by a mutant retinoblastoma protein in the transgenic mice is caused by an upregulation of c-Myc target genes

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    Wang, Bo; Hikosaka, Keisuke; Sultana, Nishat; Sharkar, Mohammad Tofael Kabir [Department of Biochemistry, Hamamatsu University School of Medicine, 1-20-1 Handa-yama, Higashi-ku, Hamamatsu 431-3192 (Japan); Noritake, Hidenao [Department of Biochemistry, Hamamatsu University School of Medicine, 1-20-1 Handa-yama, Higashi-ku, Hamamatsu 431-3192 (Japan); Department of Internal Medicine, Hamamatsu University School of Medicine, 1-20-1 Handa-yama, Higashi-ku, Hamamatsu 431-3192 (Japan); Kimura, Wataru; Wu, Yi-Xin [Department of Biochemistry, Hamamatsu University School of Medicine, 1-20-1 Handa-yama, Higashi-ku, Hamamatsu 431-3192 (Japan); Kobayashi, Yoshimasa [Department of Internal Medicine, Hamamatsu University School of Medicine, 1-20-1 Handa-yama, Higashi-ku, Hamamatsu 431-3192 (Japan); Uezato, Tadayoshi [Department of Biochemistry, Hamamatsu University School of Medicine, 1-20-1 Handa-yama, Higashi-ku, Hamamatsu 431-3192 (Japan); Miura, Naoyuki, E-mail: nmiura@hama-med.ac.jp [Department of Biochemistry, Hamamatsu University School of Medicine, 1-20-1 Handa-yama, Higashi-ku, Hamamatsu 431-3192 (Japan)

    2012-01-06

    Highlights: Black-Right-Pointing-Pointer Fifty percent of the mutant Rb transgenic mice produced liver tumors. Black-Right-Pointing-Pointer In the tumor, Foxm1, Skp2, Bmi1 and AP-1 mRNAs were up-regulated. Black-Right-Pointing-Pointer No increase in expression of the Myc-target genes was observed in the non-tumorous liver. Black-Right-Pointing-Pointer Tumor formation depends on up-regulation of the Myc-target genes. -- Abstract: The retinoblastoma (Rb) tumor suppressor encodes a nuclear phosphoprotein that regulates cellular proliferation, apoptosis and differentiation. In order to adapt itself to these biological functions, Rb is subjected to modification cycle, phosphorylation and dephosphorylation. To directly determine the effect of phosphorylation-resistant Rb on liver development and function, we generated transgenic mice expressing phosphorylation-resistant human mutant Rb (mt-Rb) under the control of the rat hepatocyte nuclear factor-1 gene promoter/enhancer. Expression of mt-Rb in the liver resulted in macroscopic neoplastic nodules (adenomas) with {approx}50% incidence within 15 months old. Interestingly, quantitative reverse transcriptase-PCR analysis showed that c-Myc was up-regulated in the liver of mt-Rb transgenic mice irrespective of having tumor tissues or no tumor. In tumor tissues, several c-Myc target genes, Foxm1, c-Jun, c-Fos, Bmi1 and Skp2, were also up-regulated dramatically. We determined whether mt-Rb activated the Myc promoter in the HTP9 cells and demonstrated that mt-Rb acted as an inhibitor of wild-type Rb-induced repression on the Myc promoter. Our results suggest that continued upregulation of c-Myc target genes promotes the liver tumor formation after about 1 year of age.

  20. MYC is a metastasis gene for non-small-cell lung cancer.

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    Ulf R Rapp

    Full Text Available BACKGROUND: Metastasis is a process by which cancer cells learn to form satellite tumors in distant organs and represents the principle cause of death of patients with solid tumors. NSCLC is the most lethal human cancer due to its high rate of metastasis. METHODOLOGY/PRINCIPAL FINDINGS: Lack of a suitable animal model has so far hampered analysis of metastatic progression. We have examined c-MYC for its ability to induce metastasis in a C-RAF-driven mouse model for non-small-cell lung cancer. c-MYC alone induced frank tumor growth only after long latency at which time secondary mutations in K-Ras or LKB1 were detected reminiscent of human NSCLC. Combination with C-RAF led to immediate acceleration of tumor growth, conversion to papillary epithelial cells and angiogenic switch induction. Moreover, addition of c-MYC was sufficient to induce macrometastasis in liver and lymph nodes with short latency associated with lineage switch events. Thus we have generated the first conditional model for metastasis of NSCLC and identified a gene, c-MYC that is able to orchestrate all steps of this process. CONCLUSIONS/SIGNIFICANCE: Potential markers for detection of metastasis were identified and validated for diagnosis of human biopsies. These markers may represent targets for future therapeutic intervention as they include genes such as Gata4 that are exclusively expressed during lung development.

  1. Transduction of Oct6 or Oct9 gene concomitant with Myc family gene induced osteoblast-like phenotypic conversion in normal human fibroblasts.

    Science.gov (United States)

    Mizoshiri, N; Kishida, T; Yamamoto, K; Shirai, T; Terauchi, R; Tsuchida, S; Mori, Y; Ejima, A; Sato, Y; Arai, Y; Fujiwara, H; Yamamoto, T; Kanamura, N; Mazda, O; Kubo, T

    2015-11-27

    Osteoblasts play essential roles in bone formation and regeneration, while they have low proliferation potential. Recently we established a procedure to directly convert human fibroblasts into osteoblasts (dOBs). Transduction of Runx2 (R), Osterix (X), Oct3/4 (O) and L-myc (L) genes followed by culturing under osteogenic conditions induced normal human fibroblasts to express osteoblast-specific genes and produce calcified bone matrix both in vitro and in vivo Intriguingly, a combination of only two factors, Oct3/4 and L-myc, significantly induced osteoblast-like phenotype in fibroblasts, but the mechanisms underlying the direct conversion remains to be unveiled. We examined which Oct family genes and Myc family genes are capable of inducing osteoblast-like phenotypic conversion. As result Oct3/4, Oct6 and Oct9, among other Oct family members, had the capability, while N-myc was the most effective Myc family gene. The Oct9 plus N-myc was the best combination to induce direct conversion of human fibroblasts into osteoblast-like cells. The present findings may greatly contribute to the elucidation of the roles of the Oct and Myc proteins in osteoblast direct reprogramming. The results may also lead to establishment of novel regenerative therapy for various bone resorption diseases. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Genetic and genomic analysis modeling of germline c-MYC overexpression and cancer susceptibility

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    Nunes Virginia

    2008-01-01

    Full Text Available Abstract Background Germline genetic variation is associated with the differential expression of many human genes. The phenotypic effects of this type of variation may be important when considering susceptibility to common genetic diseases. Three regions at 8q24 have recently been identified to independently confer risk of prostate cancer. Variation at 8q24 has also recently been associated with risk of breast and colorectal cancer. However, none of the risk variants map at or relatively close to known genes, with c-MYC mapping a few hundred kilobases distally. Results This study identifies cis-regulators of germline c-MYC expression in immortalized lymphocytes of HapMap individuals. Quantitative analysis of c-MYC expression in normal prostate tissues suggests an association between overexpression and variants in Region 1 of prostate cancer risk. Somatic c-MYC overexpression correlates with prostate cancer progression and more aggressive tumor forms, which was also a pathological variable associated with Region 1. Expression profiling analysis and modeling of transcriptional regulatory networks predicts a functional association between MYC and the prostate tumor suppressor KLF6. Analysis of MYC/Myc-driven cell transformation and tumorigenesis substantiates a model in which MYC overexpression promotes transformation by down-regulating KLF6. In this model, a feedback loop through E-cadherin down-regulation causes further transactivation of c-MYC. Conclusion This study proposes that variation at putative 8q24 cis-regulator(s of transcription can significantly alter germline c-MYC expression levels and, thus, contribute to prostate cancer susceptibility by down-regulating the prostate tumor suppressor KLF6 gene.

  3. c-Myc Antagonises the Transcriptional Activity of the Androgen Receptor in Prostate Cancer Affecting Key Gene Networks.

    Science.gov (United States)

    Barfeld, Stefan J; Urbanucci, Alfonso; Itkonen, Harri M; Fazli, Ladan; Hicks, Jessica L; Thiede, Bernd; Rennie, Paul S; Yegnasubramanian, Srinivasan; DeMarzo, Angelo M; Mills, Ian G

    2017-04-01

    Prostate cancer (PCa) is the most common non-cutaneous cancer in men. The androgen receptor (AR), a ligand-activated transcription factor, constitutes the main drug target for advanced cases of the disease. However, a variety of other transcription factors and signaling networks have been shown to be altered in patients and to influence AR activity. Amongst these, the oncogenic transcription factor c-Myc has been studied extensively in multiple malignancies and elevated protein levels of c-Myc are commonly observed in PCa. Its impact on AR activity, however, remains elusive. In this study, we assessed the impact of c-Myc overexpression on AR activity and transcriptional output in a PCa cell line model and validated the antagonistic effect of c-MYC on AR-targets in patient samples. We found that c-Myc overexpression partially reprogrammed AR chromatin occupancy and was associated with altered histone marks distribution, most notably H3K4me1 and H3K27me3. We found c-Myc and the AR co-occupy a substantial number of binding sites and these exhibited enhancer-like characteristics. Interestingly, c-Myc overexpression antagonised clinically relevant AR target genes. Therefore, as an example, we validated the antagonistic relationship between c-Myc and two AR target genes, KLK3 (alias PSA, prostate specific antigen), and Glycine N-Methyltransferase (GNMT), in patient samples. Our findings provide unbiased evidence that MYC overexpression deregulates the AR transcriptional program, which is thought to be a driving force in PCa. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  4. c-Myc Antagonises the Transcriptional Activity of the Androgen Receptor in Prostate Cancer Affecting Key Gene Networks

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    Stefan J. Barfeld

    2017-04-01

    Full Text Available Prostate cancer (PCa is the most common non-cutaneous cancer in men. The androgen receptor (AR, a ligand-activated transcription factor, constitutes the main drug target for advanced cases of the disease. However, a variety of other transcription factors and signaling networks have been shown to be altered in patients and to influence AR activity. Amongst these, the oncogenic transcription factor c-Myc has been studied extensively in multiple malignancies and elevated protein levels of c-Myc are commonly observed in PCa. Its impact on AR activity, however, remains elusive. In this study, we assessed the impact of c-Myc overexpression on AR activity and transcriptional output in a PCa cell line model and validated the antagonistic effect of c-MYC on AR-targets in patient samples. We found that c-Myc overexpression partially reprogrammed AR chromatin occupancy and was associated with altered histone marks distribution, most notably H3K4me1 and H3K27me3. We found c-Myc and the AR co-occupy a substantial number of binding sites and these exhibited enhancer-like characteristics. Interestingly, c-Myc overexpression antagonised clinically relevant AR target genes. Therefore, as an example, we validated the antagonistic relationship between c-Myc and two AR target genes, KLK3 (alias PSA, prostate specific antigen, and Glycine N-Methyltransferase (GNMT, in patient samples. Our findings provide unbiased evidence that MYC overexpression deregulates the AR transcriptional program, which is thought to be a driving force in PCa.

  5. Transcriptional regulation of BRD7 expression by Sp1 and c-Myc

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    Li Shufang

    2008-12-01

    Full Text Available Abstract Background Bromodomain is an evolutionally conserved domain that is found in proteins strongly implicated in signal-dependent transcriptional regulation. Genetic alterations of bromodomain genes contributed to the development of many human cancers and other disorders. BRD7 is a recently identified bromodomain gene. It plays a critical role in cellular growth, cell cycle progression, and signal-dependent gene expression. Previous studies showed that BRD7 gene exhibited much higher-level of mRNA expression in normal nasopharyngeal epithelia than in nasopharyngeal carcinoma (NPC biopsies and cell lines. However, little is known about its transcriptional regulation. In this study, we explored the transcriptional regulation of BRD7 gene. Method Potential binding sites of transcription factors within the promoter region of BRD7 gene were predicted with MatInspector Professional http://genomatix.de/cgi-bin/matinspector_prof/mat_fam.pl. Mutation construct methods and luciferase assays were performed to define the minimal promoter of BRD7 gene. RT-PCR and western blot assays were used to detect the endogenous expression of transcription factor Sp1, c-Myc and E2F6 in all cell lines used in this study. Electrophoretic mobility shift assays (EMSA and Chromatin immunoprecipitation (ChIP were used to detect the direct transcription factors that are responsible for the promoter activity of BRD7 gene. DNA vector-based siRNA technology and cell transfection methods were employed to establish clone pools that stably expresses SiRNA against c-Myc expression in nasopharyngeal carcinoma 5-8F cells. Real-time PCR was used to detect mRNA expression of BRD7 gene in 5-8F/Si-c-Myc cells. Results We defined the minimal promoter of BRD7 gene in a 55-bp region (from -266 to -212bp, and identified that its promoter activity is inversely related to c-Myc expression. Sp1 binds to the Sp1/Myc-Max overlapping site of BRD7 minimal promoter, and slightly positively

  6. Human amniotic epithelial cell feeder layers maintain mouse embryonic stem cell pluripotency via epigenetic regulation of the c-Myc promoter.

    Science.gov (United States)

    Liu, Te; Cheng, Weiwei; Liu, Tianjin; Guo, Lihe; Huang, Qin; Jiang, Lizhen; Du, Xiling; Xu, Fuhui; Liu, Zhixue; Lai, Dongmei

    2010-02-01

    Mouse embryonic stem cells (ESCs) are typically cultured on a feeder layer of mouse embryonic fibroblasts (MEFs), with leukemia inhibitory factor (LIF) added to maintain them in an undifferentiated state. We have previously shown that human amniotic epithelial cells (hAECs) can be used as feeder cells to maintain mouse ESC pluripotency, but the mechanism for this is unknown. In the present study, we found that CpG islands 5' of the c-Myc gene remain hypomethylated in mouse ESCs cultured on hAECs. In addition, levels of acetylation of histone H3 and trimethylation of histone H3K4 in the c-Myc gene promoter were higher in ES cells cultured on hAECs than those in ES cells cultured on MEFs. These data suggested that hAECs can alter mouse ESC gene expression via epigenetic modification of c-Myc, providing a possible mechanism for the hAEC-induced maintenance of ESCs in an undifferentiated state.

  7. Postnatal liver growth and regeneration are independent of c-myc in a mouse model of conditional hepatic c-myc deletion

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    Sanders Jennifer A

    2012-03-01

    Full Text Available Abstract Background The transcription factor c-myc regulates genes involved in hepatocyte growth, proliferation, metabolism, and differentiation. It has also been assigned roles in liver development and regeneration. In previous studies, we made the unexpected observation that c-Myc protein levels were similar in proliferating fetal liver and quiescent adult liver with c-Myc displaying nucleolar localization in the latter. In order to investigate the functional role of c-Myc in adult liver, we have developed a hepatocyte-specific c-myc knockout mouse, c-mycfl/fl;Alb-Cre. Results Liver weight to body weight ratios were similar in control and c-myc deficient mice. Liver architecture was unaffected. Conditional c-myc deletion did not result in compensatory induction of other myc family members or in c-Myc's binding partner Max. Floxed c-myc did have a negative effect on Alb-Cre expression at 4 weeks of age. To explore this relationship further, we used the Rosa26 reporter line to assay Cre activity in the c-myc floxed mice. No significant difference in Alb-Cre activity was found between control and c-mycfl/fl mice. c-myc deficient mice were studied in a nonproliferative model of liver growth, fasting for 48 hr followed by a 24 hr refeeding period. Fasting resulted in a decrease in liver mass and liver protein, both of which recovered upon 24 h of refeeding in the c-mycfl/fl;Alb-Cre animals. There was also no effect of reducing c-myc on recovery of liver mass following 2/3 partial hepatectomy. Conclusions c-Myc appears to be dispensable for normal liver growth during the postnatal period, restoration of liver mass following partial hepatectomy and recovery from fasting.

  8. Genomic amplification patterns of human telomerase RNA gene and C-MYC in liquid-based cytological specimens used for the detection of high-grade cervical intraepithelial neoplasia

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    Chen Shaomin

    2012-04-01

    Full Text Available Abstract Background The amplification of oncogenes initiated by high-risk human papillomavirus (HPV infection is an early event in cervical carcinogenesis and can be used for cervical lesion diagnosis. We measured the genomic amplification rates and the patterns of human telomerase RNA gene (TERC and C-MYC in the liquid-based cytological specimens to evaluate the diagnostic characteristics for the detection of high-grade cervical lesions. Methods Two hundred and forty-three residual cytological specimens were obtained from outpatients aged 25 to 64 years at Qilu Hospital, Shandong University. The specimens were evaluated by fluorescence in situ hybridization (FISH using chromosome probes to TERC (3q26 and C-MYC (8q24. All of the patients underwent colposcopic examination and histological evaluation. A Chi-square test was used for categorical data analysis. Results In the normal, cervical intraepithelial neoplasia grade 1 (CIN1, grade 2 (CIN2, grade 3 (CIN3 and squamous cervical cancer (SCC cases, the TERC positive rates were 9.2%, 17.2%, 76.2%, 100.0% and 100.0%, respectively; the C-MYC positive rates were 20.7%, 31.0%, 71.4%, 81.8% and 100.0%, respectively. The TERC and C-MYC positive rates were higher in the CIN2+ (CIN2, CIN3 and SCC cases than in the normal and CIN1 cases (p p p > 0.05. Conclusions The TERC test is highly sensitive and is therefore suitable for cervical cancer screening. The C-MYC test is not suitable for cancer screening because of its lower sensitivity. The amplification patterns of TERC become more diverse and complex as the severity of cervical diseases increases, whereas for C-MYC, the amplification patterns are similar between the normal/CIN1 and CIN2+ groups. Virtual slides The virtual slide(s for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1308004512669913.

  9. Human RNA polymerase II associated factor 1 complex promotes tumorigenesis by activating c-MYC transcription in non-small cell lung cancer

    International Nuclear Information System (INIS)

    Zhi, Xiuyi; Giroux-Leprieur, Etienne; Wislez, Marie; Hu, Mu; Zhang, Yi; Shi, Huaiyin; Du, Kaiqi; Wang, Lei

    2015-01-01

    Human RNA polymerase II (RNAPII)-associated factor 1 complex (hPAF1C) plays a crucial role in protein-coding gene transcription. Overexpression of hPAF1C has been implicated in the initiation and progression of various human cancers. However, the molecular pathways involved in tumorigenesis through hPAF1C remain to be elucidated. The current study suggested hPAF1C expression as a prognostic biomarker for early stage non-small cell lung cancer (NSCLC) and patients with low hPAF1C expression levels had significantly better overall survival. Furthermore, the expression of hPAF1C was found to be positively correlated with c-MYC expression in patient tumor samples and in cancer cell lines. Mechanistic studies indicated that hPAF1C could promote lung cancer cell proliferation through regulating c-MYC transcription. These results demonstrated the prognostic value of hPAF1C in early-stage NSCLC and the role of hPAF1C in the transcriptional regulation of c-MYC oncogene during NSCLC tumorigenesis. - Highlights: • hPAF1C expression is a prognostic biomarker for early stage non-small cell lung cancer. • The expression of hPAF1C was positively correlated with c-MYC in tumor samples of patients and in several NSCLC cell lines. • hPAF1C could promote lung cancer cell proliferation through regulating c-MYC transcription.

  10. Cell-type independent MYC target genes reveal a primordial signature involved in biomass accumulation.

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    Hongkai Ji

    Full Text Available The functions of key oncogenic transcription factors independent of context have not been fully delineated despite our richer understanding of the genetic alterations in human cancers. The MYC oncogene, which produces the Myc transcription factor, is frequently altered in human cancer and is a major regulatory hub for many cancers. In this regard, we sought to unravel the primordial signature of Myc function by using high-throughput genomic approaches to identify the cell-type independent core Myc target gene signature. Using a model of human B lymphoma cells bearing inducible MYC, we identified a stringent set of direct Myc target genes via chromatin immunoprecipitation (ChIP, global nuclear run-on assay, and changes in mRNA levels. We also identified direct Myc targets in human embryonic stem cells (ESCs. We further document that a Myc core signature (MCS set of target genes is shared in mouse and human ESCs as well as in four other human cancer cell types. Remarkably, the expression of the MCS correlates with MYC expression in a cell-type independent manner across 8,129 microarray samples, which include 312 cell and tissue types. Furthermore, the expression of the MCS is elevated in vivo in Eμ-Myc transgenic murine lymphoma cells as compared with premalignant or normal B lymphocytes. Expression of the MCS in human B cell lymphomas, acute leukemia, lung cancers or Ewing sarcomas has the highest correlation with MYC expression. Annotation of this gene signature reveals Myc's primordial function in RNA processing, ribosome biogenesis and biomass accumulation as its key roles in cancer and stem cells.

  11. c-Myc is essential to prevent endothelial pro-inflammatory senescent phenotype.

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    Victoria Florea

    Full Text Available The proto-oncogene c-Myc is vital for vascular development and promotes tumor angiogenesis, but the mechanisms by which it controls blood vessel growth remain unclear. In the present work we investigated the effects of c-Myc knockdown in endothelial cell functions essential for angiogenesis to define its role in the vasculature. We provide the first evidence that reduction in c-Myc expression in endothelial cells leads to a pro-inflammatory senescent phenotype, features typically observed during vascular aging and pathologies associated with endothelial dysfunction. c-Myc knockdown in human umbilical vein endothelial cells using lentivirus expressing specific anti-c-Myc shRNA reduced proliferation and tube formation. These functional defects were associated with morphological changes, increase in senescence-associated-β-galactosidase activity, upregulation of cell cycle inhibitors and accumulation of c-Myc-deficient cells in G1-phase, indicating that c-Myc knockdown in endothelial cells induces senescence. Gene expression analysis of c-Myc-deficient endothelial cells showed that senescent phenotype was accompanied by significant upregulation of growth factors, adhesion molecules, extracellular-matrix components and remodeling proteins, and a cluster of pro-inflammatory mediators, which include Angptl4, Cxcl12, Mdk, Tgfb2 and Tnfsf15. At the peak of expression of these cytokines, transcription factors known to be involved in growth control (E2f1, Id1 and Myb were downregulated, while those involved in inflammatory responses (RelB, Stat1, Stat2 and Stat4 were upregulated. Our results demonstrate a novel role for c-Myc in the prevention of vascular pro-inflammatory phenotype, supporting an important physiological function as a central regulator of inflammation and endothelial dysfunction.

  12. Gene expression profiles in primary pancreatic tumors and metastatic lesions of Ela-c-myc transgenic mice

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    Liao Dezhong J

    2008-01-01

    Full Text Available Abstract Background Pancreatic carcinoma usually is a fatal disease with no cure, mainly due to its invasion and metastasis prior to diagnosis. We analyzed the gene expression profiles of paired primary pancreatic tumors and metastatic lesions from Ela-c-myc transgenic mice in order to identify genes that may be involved in the pancreatic cancer progression. Differentially expressed selected genes were verified by semi-quantitative and quantitative RT-PCR. To further evaluate the relevance of some of the selected differentially expressed genes, we investigated their expression pattern in human pancreatic cancer cell lines with high and low metastatic potentials. Results Data indicate that genes involved in posttranscriptional regulation were a major functional category of upregulated genes in both primary pancreatic tumors (PT and liver metastatic lesions (LM compared to normal pancreas (NP. In particular, differential expression for splicing factors, RNA binding/pre-mRNA processing factors and spliceosome related genes were observed, indicating that RNA processing and editing related events may play critical roles in pancreatic tumor development and progression. High expression of insulin growth factor binding protein-1 (Igfbp1 and Serine proteinase inhibitor A1 (Serpina1, and low levels or absence of Wt1 gene expression were exclusive to liver metastatic lesion samples. Conclusion We identified Igfbp1, Serpina1 and Wt1 genes that are likely to be clinically useful biomarkers for prognostic or therapeutic purposes in metastatic pancreatic cancer, particularly in pancreatic cancer where c-Myc is overexpressed.

  13. Gene expression profiles in primary pancreatic tumors and metastatic lesions of Ela-c-myc transgenic mice.

    Science.gov (United States)

    Thakur, Archana; Bollig, Aliccia; Wu, Jiusheng; Liao, Dezhong J

    2008-01-24

    Pancreatic carcinoma usually is a fatal disease with no cure, mainly due to its invasion and metastasis prior to diagnosis. We analyzed the gene expression profiles of paired primary pancreatic tumors and metastatic lesions from Ela-c-myc transgenic mice in order to identify genes that may be involved in the pancreatic cancer progression. Differentially expressed selected genes were verified by semi-quantitative and quantitative RT-PCR. To further evaluate the relevance of some of the selected differentially expressed genes, we investigated their expression pattern in human pancreatic cancer cell lines with high and low metastatic potentials. Data indicate that genes involved in posttranscriptional regulation were a major functional category of upregulated genes in both primary pancreatic tumors (PT) and liver metastatic lesions (LM) compared to normal pancreas (NP). In particular, differential expression for splicing factors, RNA binding/pre-mRNA processing factors and spliceosome related genes were observed, indicating that RNA processing and editing related events may play critical roles in pancreatic tumor development and progression. High expression of insulin growth factor binding protein-1 (Igfbp1) and Serine proteinase inhibitor A1 (Serpina1), and low levels or absence of Wt1 gene expression were exclusive to liver metastatic lesion samples. We identified Igfbp1, Serpina1 and Wt1 genes that are likely to be clinically useful biomarkers for prognostic or therapeutic purposes in metastatic pancreatic cancer, particularly in pancreatic cancer where c-Myc is overexpressed.

  14. Acetylation of the c-MYC oncoprotein is required for cooperation with the HTLV-1 p30{sup II} accessory protein and the induction of oncogenic cellular transformation by p30{sup II}/c-MYC

    Energy Technology Data Exchange (ETDEWEB)

    Romeo, Megan M.; Ko, Bookyung; Kim, Janice; Brady, Rebecca; Heatley, Hayley C.; He, Jeffrey; Harrod, Carolyn K.; Barnett, Braden [Laboratory of Molecular Virology, Department of Biological Sciences, and The Dedman College Center for Drug Discovery, Design, and Delivery, Southern Methodist University, Dallas, TX 75275-0376 (United States); Ratner, Lee [Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110 (United States); Lairmore, Michael D. [University of California-Davis, School of Veterinary Medicine, One Shields Avenue, Davis, CA 95618 (United States); Martinez, Ernest [Department of Biochemistry, University of California, Riverside, CA 92521 (United States); Lüscher, Bernhard [Institute of Biochemistry, Klinikum, RWTH Aachen University, Pauwelsstrasse 30, 52057 Aachen (Germany); Robson, Craig N. [Northern Institute for Cancer Research, Newcastle University, The Medical School, Newcastle upon Tyne, NE2 4HH (United Kingdom); Henriksson, Marie [Department of Microbiology, Cell and Tumor Biology, Karolinska Institutet, Stockholm (Sweden); Harrod, Robert, E-mail: rharrod@smu.edu [Laboratory of Molecular Virology, Department of Biological Sciences, and The Dedman College Center for Drug Discovery, Design, and Delivery, Southern Methodist University, Dallas, TX 75275-0376 (United States)

    2015-02-15

    The human T-cell leukemia retrovirus type-1 (HTLV-1) p30{sup II} protein is a multifunctional latency-maintenance factor that negatively regulates viral gene expression and deregulates host signaling pathways involved in aberrant T-cell growth and proliferation. We have previously demonstrated that p30{sup II} interacts with the c-MYC oncoprotein and enhances c-MYC-dependent transcriptional and oncogenic functions. However, the molecular and biochemical events that mediate the cooperation between p30{sup II} and c-MYC remain to be completely understood. Herein we demonstrate that p30{sup II} induces lysine-acetylation of the c-MYC oncoprotein. Acetylation-defective c-MYC Lys→Arg substitution mutants are impaired for oncogenic transformation with p30{sup II} in c-myc{sup −/−} HO15.19 fibroblasts. Using dual-chromatin-immunoprecipitations (dual-ChIPs), we further demonstrate that p30{sup II} is present in c-MYC-containing nucleoprotein complexes in HTLV-1-transformed HuT-102 T-lymphocytes. Moreover, p30{sup II} inhibits apoptosis in proliferating cells expressing c-MYC under conditions of genotoxic stress. These findings suggest that c-MYC-acetylation is required for the cooperation between p30{sup II}/c-MYC which could promote proviral replication and contribute to HTLV-1-induced carcinogenesis. - Highlights: • Acetylation of c-MYC is required for oncogenic transformation by HTLV-1 p30{sup II}/c-MYC. • Acetylation-defective c-MYC mutants are impaired for foci-formation by p30{sup II}/c-MYC. • The HTLV-1 p30{sup II} protein induces lysine-acetylation of c-MYC. • p30{sup II} is present in c-MYC nucleoprotein complexes in HTLV-1-transformed T-cells. • HTLV-1 p30{sup II} inhibits apoptosis in c-MYC-expressing proliferating cells.

  15. Ezrin mediates c-Myc actions in prostate cancer cell invasion

    DEFF Research Database (Denmark)

    Chuan, Yin Choy; Iglesias Gato, Diego; Fernandez-Perez, L

    2010-01-01

    The forced overexpression of c-Myc in mouse prostate and in normal human prostate epithelial cells results in tumor transformation with an invasive phenotype. How c-Myc regulates cell invasion is poorly understood. In this study, we have investigated the interplay of c-Myc and androgens in the re...

  16. Insertion of the LINE-1 element in the C-MYC gene and immunoreactivity of C-MYC, p53, p21 and p27 proteins in different morphological patterns of the canine TVT

    Directory of Open Access Journals (Sweden)

    C.R.O. Lima

    2016-06-01

    Full Text Available ABSTRACT The canine transmissible venereal tumor (TVT affects the external genitalia of dogs by the natural transplant of viable tumor cells. Thus, this research aimed to diagnose and characterize TVT morphological patterns, identify the insertion of the LINE-1 element in C-MYC gene, by means of the polymerase chain reaction (PCR, and evaluate the immunohistochemical expression of C-MYC, p53, p21 and p27 proteins. The relationship between C-MYC and p53 proteins and their interference on the expression of p21 and p27 were also studied. For that, 20 samples of naturally occurring TVT were used, subjected to cytopathological, histopathological and immunohistochemical analysis, and to molecular diagnosis of neoplasia. The increased tissue expression and the correlation among C-MYC, p53, p21 and p27 proteins indicate reduction and/or loss of their functionality in the TVT microenvironment, with consequent apoptotic suppression, maintenance of cell growth and progression of neoplasia.

  17. Fluorescent Dansyl-Guanosine Conjugates that Bind c-MYC Promoter G-Quadruplex and Downregulate c-MYC Expression.

    Science.gov (United States)

    Pavan Kumar, Y; Saha, Puja; Saha, Dhurjhoti; Bessi, Irene; Schwalbe, Harald; Chowdhury, Shantanu; Dash, Jyotirmayee

    2016-03-02

    The four-stranded G-quadruplex present in the c-MYC P1 promoter has been shown to play a pivotal role in the regulation of c-MYC transcription. Small-molecule compounds capable of inhibiting the c-MYC promoter activity by stabilising the c-MYC G-quadruplex could potentially be used as anticancer agents. In this context, here we report the synthesis of dansyl-guanosine conjugates through one-pot modular click reactions. The dansyl-guanosine conjugates can selectively detect c-MYC G-quadruplex over other biologically relevant quadruplexes and duplex DNA and can be useful as staining reagents for selective visualisation of c-MYC G-quadruplex over duplex DNA by gel electrophoresis. NMR spectroscopic titrations revealed the preferential binding sites of these dansyl ligands to the c-MYC G-quadruplex. A dual luciferase assay and qRT-PCR revealed that a dansyl-bisguanosine ligand represses the c-MYC expression, possibly by stabilising the c-MYC G-quadruplex. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Profil Ekspresi mRNA Gen Murine Double Minute2, Kruppel-Like Factor4, dan c-Myc pada Fibrosarkoma

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    - Humaryanto

    2017-02-01

    Full Text Available Abstrak Fibrosarkoma hanya terjadi 1–3% dari seluruh keganasan jaringan lunak. Hingga saat ini etiologi fibrosarkoma belum diketahui dengan pasti. Beberapa faktor dapat menjadi penyebab patogenesis fibrosarkoma antara lain radiasi, terpapar zat kimia tertentu, serta infeksi human herpes virus 8 (HHV8 dan Epstein-Barr virus (EBV. Penelitian terkini menunjukkan bahwa banyak sarkoma terkait dengan mutasi genetik. Penelitian ini bertujuan melihat profil ekspresi mRNA gen Krüppel-like Factor4, Murine Double Minute2, dan c-Myc pada fibrosarkoma menggunakan teknik real time PCR kuantitatif (quantitative real time PCR, qRT-PCR. Analisis data menggunakan metode kuantititatif relatif 2-ΔΔCt. Penelitian ini menggunakan 10 sampel kasus fibrosarkoma yang ditemukan di Kota Jambi dari tahun 2011–2015. Hasil ΔCt (+SD MDM2, KLF-4, dan c-Myc disusun dari nilai yang terkecil hingga tertinggi adalah 1,85±2,14; 2,06±3,86; 2,9±2,66 secara berurutan. Dibanding dengan level ekspresi dengan GAPDH sebagai housekeeping gene, gen MDM2 dan KLF-4 relatif menurun dua kali lipat, sedangkan gen c-Myc relatif menurun lebih dari tiga kali lipat. Simpulan, penelitian ini menunjukkan bahwa pada kasus fibrosarkoma, gen c-Myc disupresi lebih kuat dibanding dengan gen MDM2 dan KLF-4. Abstract Fibrosarcoma is a rare soft tissue sarcoma, reported only 1–3% of all soft tissue sarcomas. Like any other soft-tissue sarcomas the definitive caused has not yet understood. Recognized causes include exposure to ionizing radiation, various physical and chemical factors, infection with human herpes virus (HHV8 and Epstein-Barr virus (EBV. Current research indicates many sarcomas are associated with genetic mutations. In this study, we investigated profile of mRNA gene expression KLF4, MDM2, and c-Myc of RNA in fibrosarcoma cases. The genes expression was examined using quantitative real time PCR (qRT-PCR and we analyzed the relative gene expression using the 2-ΔΔCt method. Ten

  19. Cytotoxic effect of γ-sitosterol from Kejibeling (Strobilanthes crispus and its mechanism of action towards c-myc gene expression and apoptotic pathway

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    Susi Endrini

    2015-01-01

    Full Text Available Background: This study aimed to analyze the cytotoxicity effect of γ-sitosterol isolated from “Kejibeling” (Strobilanthes crispus, a medicinal plant, on several cancer cell lines. The mechanisms of the effects were studied through the expression of cancer-caused gene, c-myc and apoptotic pathways.Methods: This in vitro study was done using human colon cancer cell lines (Caco-2, liver cancer cell lines (HepG2, hormone-dependent breast cancer cell lines (MCF-7 and the normal liver cell lines (Chang Liver. The cytotoxic effect was measured through MTT assay and the potential cytotoxic value was calculated by determining the toxic concentration which may kill up to 50% of the total cell used (IC50. Meanwhile, the cytotoxic mechanism was studied by determining the effect of adding γ-sitosterol to the c-myc gene expression by reverse transciptase-polymerase chain reaction (RT-PCR. The effect of γ-sitosterol through apoptotic pathway was studied by using terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL assay.Results: γ-sitosterol was cytotoxic against Caco-2, HepG2, and MCF-7 with IC50-values of 8.3, 21.8, and 28.8 μg/mL, respectively. There were no IC50-values obtained from this compound against Chang Liver cell line. This compound induced apotosis on Caco-2 and HepG2 cell lines and suppressed the c-myc genes expression in both cells.Conclusion: γ-sitosterol was cytotoxic against colon and liver cancer cell lines and the effect was mediated by down-regulation of c-myc expression and induction of the apoptotic pathways.

  20. Histopathological and molecular prognostic markers in medulloblastoma: c-myc, N-myc, TrkC, and anaplasia.

    Science.gov (United States)

    Eberhart, Charles G; Kratz, John; Wang, Yunyue; Summers, Krista; Stearns, Duncan; Cohen, Kenneth; Dang, Chi V; Burger, Peter C

    2004-05-01

    Several molecular and histopathological prognostic markers have been proposed for the therapeutic stratification of medulloblastoma patients. Amplification of the c-myc oncogene, elevated levels of c-myc mRNA, or tumor anaplasia have been associated with worse clinical outcomes. In contrast, high TrkC mRNA expression generally presages longer survival. The goal of this study was to evaluate the prognostic value of c-myc, N-myc and TrkC expression in medulloblastomas and compare them to histopathological classification. We used in situ hybridization to measure expression of these molecular markers. c-myc mRNA was detected in 18 of 59 (31%) cases, and was significantly associated with shorter patient survival times on both univariate and multivariate analyses (p = 0.04). The presence of c-myc mRNA was also significantly associated with tumor anaplasia. While survival rates were higher for patients with low N-myc or high TrkC expression, these differences were not statistically significant. The group of patients with either moderate or severely anaplastic tumors showed only a trend towards shorter survival (p = 0.11). However, severe anaplasia alone was significantly prognostic (p = 0.002). Given the prognostic import of c-myc, we investigated 2 potential mechanisms by which its expression might be regulated: Wnt signaling and Mxi-1 mutation. Nuclear translocation of beta-catenin, a marker of Wnt pathway activation, was more common in medulloblastomas with high c-myc than in tumors overall, but the difference was not statistically significant. No Mxi-1 mutations were detected in the 22 cases examined. The association we describe between c-myc expression, tumor anaplasia, and worse clinical outcomes provides further evidence for the importance of this oncogene in medulloblastoma pathobiology.

  1. Clinicopathological significance of c-MYC in esophageal squamous cell carcinoma.

    Science.gov (United States)

    Lian, Yu; Niu, Xiangdong; Cai, Hui; Yang, Xiaojun; Ma, Haizhong; Ma, Shixun; Zhang, Yupeng; Chen, Yifeng

    2017-07-01

    Esophageal squamous cell carcinoma is one of the most common malignant tumors. The oncogene c-MYC is thought to be important in the initiation, promotion, and therapy resistance of cancer. In this study, we aim to investigate the clinicopathologic roles of c-MYC in esophageal squamous cell carcinoma tissue. This study is aimed at discovering and analyzing c-MYC expression in a series of human esophageal tissues. A total of 95 esophageal squamous cell carcinoma samples were analyzed by the western blotting and immunohistochemistry techniques. Then, correlation of c-MYC expression with clinicopathological features of esophageal squamous cell carcinoma patients was statistically analyzed. In most esophageal squamous cell carcinoma cases, the c-MYC expression was positive in tumor tissues. The positive rate of c-MYC expression in tumor tissues was 61.05%, obviously higher than the adjacent normal tissues (8.42%, 8/92) and atypical hyperplasia tissues (19.75%, 16/95). There was a statistical difference among adjacent normal tissues, atypical hyperplasia tissues, and tumor tissues. Overexpression of the c-MYC was detected in 61.05% (58/95) esophageal squamous cell carcinomas, which was significantly correlated with the degree of differentiation (p = 0.004). The positive rate of c-MYC expression was 40.0% in well-differentiated esophageal tissues, with a significantly statistical difference (p = 0.004). The positive rate of c-MYC was 41.5% in T1 + T2 esophageal tissues and 74.1% in T3 + T4 esophageal tissues, with a significantly statistical difference (p = 0.001). The positive rate of c-MYC was 45.0% in I + II esophageal tissues and 72.2% in III + IV esophageal tissues, with a significantly statistical difference (p = 0.011). The c-MYC expression strongly correlated with clinical staging (p = 0.011), differentiation degree (p = 0.004), lymph node metastasis (p = 0.003), and invasion depth (p = 0.001) of patients with esophageal squamous cell carcinoma. The c-MYC was

  2. Acidosis Decreases c-Myc Oncogene Expression in Human Lymphoma Cells: A Role for the Proton-Sensing G Protein-Coupled Receptor TDAG8

    Directory of Open Access Journals (Sweden)

    Zhigang Li

    2013-10-01

    Full Text Available Acidosis is a biochemical hallmark of the tumor microenvironment. Here, we report that acute acidosis decreases c-Myc oncogene expression in U937 human lymphoma cells. The level of c-Myc transcripts, but not mRNA or protein stability, contributes to c-Myc protein reduction under acidosis. The pH-sensing receptor TDAG8 (GPR65 is involved in acidosis-induced c-Myc downregulation. TDAG8 is expressed in U937 lymphoma cells, and the overexpression or knockdown of TDAG8 further decreases or partially rescues c-Myc expression, respectively. Acidic pH alone is insufficient to reduce c-Myc expression, as it does not decrease c-Myc in H1299 lung cancer cells expressing very low levels of pH-sensing G protein-coupled receptors (GPCRs. Instead, c-Myc is slightly increased by acidosis in H1299 cells, but this increase is completely inhibited by ectopic overexpression of TDAG8. Interestingly, TDAG8 expression is decreased by more than 50% in human lymphoma samples in comparison to non-tumorous lymph nodes and spleens, suggesting a potential tumor suppressor function of TDAG8 in lymphoma. Collectively, our results identify a novel mechanism of c-Myc regulation by acidosis in the tumor microenvironment and indicate that modulation of TDAG8 and related pH-sensing receptor pathways may be exploited as a new approach to inhibit Myc expression.

  3. The c-myc oncoprotein forms a specific complex with the product of the retinoblastoma gene

    NARCIS (Netherlands)

    Bernards, R.A.; Rustgi, A.K.; Dyson, N.; Hill, D.

    1991-01-01

    Myc proteins are involved in the regulation of cell proliferation and differentiation. Deregulated expression of myc family genes has been implicated in the genesis of a variety of cancers. Myc proteins share significant sequence homology in the carboxyl terminus with a number of

  4. Mechanisms of c-myc degradation by nickel compounds and hypoxia.

    Directory of Open Access Journals (Sweden)

    Qin Li

    2009-12-01

    Full Text Available Nickel (Ni compounds have been found to cause cancer in humans and animal models and to transform cells in culture. At least part of this effect is mediated by stabilization of hypoxia inducible factor (HIF1a and activating its downstream signaling. Recent studies reported that hypoxia signaling might either antagonize or enhance c-myc activity depending on cell context. We investigated the effect of nickel on c-myc levels, and demonstrated that nickel, hypoxia, and other hypoxia mimetics degraded c-myc protein in a number of cancer cells (A549, MCF-7, MDA-453, and BT-474. The degradation of the c-Myc protein was mediated by the 26S proteosome. Interestingly, knockdown of both HIF-1alpha and HIF-2alpha attenuated c-Myc degradation induced by Nickel and hypoxia, suggesting the functional HIF-1alpha and HIF-2alpha was required for c-myc degradation. Further studies revealed two potential pathways mediated nickel and hypoxia induced c-myc degradation. Phosphorylation of c-myc at T58 was significantly increased in cells exposed to nickel or hypoxia, leading to increased ubiquitination through Fbw7 ubiquitin ligase. In addition, nickel and hypoxia exposure decreased USP28, a c-myc de-ubiquitinating enzyme, contributing to a higher steady state level of c-myc ubiquitination and promoting c-myc degradation. Furthermore, the reduction of USP28 protein by hypoxia signaling is due to both protein degradation and transcriptional repression. Nickel and hypoxia exposure significantly increased the levels of dimethylated H3 lysine 9 at the USP28 promoter and repressed its expression. Our study demonstrated that Nickel and hypoxia exposure increased c-myc T58 phosphorylation and decreased USP28 protein levels in cancer cells, which both lead to enhanced c-myc ubiquitination and proteasomal degradation.

  5. Nuclear AXIN2 represses MYC gene expression

    Energy Technology Data Exchange (ETDEWEB)

    Rennoll, Sherri A.; Konsavage, Wesley M.; Yochum, Gregory S., E-mail: gsy3@psu.edu

    2014-01-03

    Highlights: •AXIN2 localizes to cytoplasmic and nuclear compartments in colorectal cancer cells. •Nuclear AXIN2 represses the activity of Wnt-responsive luciferase reporters. •β-Catenin bridges AXIN2 to TCF transcription factors. •AXIN2 binds the MYC promoter and represses MYC gene expression. -- Abstract: The β-catenin transcriptional coactivator is the key mediator of the canonical Wnt signaling pathway. In the absence of Wnt, β-catenin associates with a cytosolic and multi-protein destruction complex where it is phosphorylated and targeted for proteasomal degradation. In the presence of Wnt, the destruction complex is inactivated and β-catenin translocates into the nucleus. In the nucleus, β-catenin binds T-cell factor (TCF) transcription factors to activate expression of c-MYC (MYC) and Axis inhibition protein 2 (AXIN2). AXIN2 is a member of the destruction complex and, thus, serves in a negative feedback loop to control Wnt/β-catenin signaling. AXIN2 is also present in the nucleus, but its function within this compartment is unknown. Here, we demonstrate that AXIN2 localizes to the nuclei of epithelial cells within normal and colonic tumor tissues as well as colorectal cancer cell lines. In the nucleus, AXIN2 represses expression of Wnt/β-catenin-responsive luciferase reporters and forms a complex with β-catenin and TCF. We demonstrate that AXIN2 co-occupies β-catenin/TCF complexes at the MYC promoter region. When constitutively localized to the nucleus, AXIN2 alters the chromatin structure at the MYC promoter and directly represses MYC gene expression. These findings suggest that nuclear AXIN2 functions as a rheostat to control MYC expression in response to Wnt/β-catenin signaling.

  6. Nuclear AXIN2 represses MYC gene expression

    International Nuclear Information System (INIS)

    Rennoll, Sherri A.; Konsavage, Wesley M.; Yochum, Gregory S.

    2014-01-01

    Highlights: •AXIN2 localizes to cytoplasmic and nuclear compartments in colorectal cancer cells. •Nuclear AXIN2 represses the activity of Wnt-responsive luciferase reporters. •β-Catenin bridges AXIN2 to TCF transcription factors. •AXIN2 binds the MYC promoter and represses MYC gene expression. -- Abstract: The β-catenin transcriptional coactivator is the key mediator of the canonical Wnt signaling pathway. In the absence of Wnt, β-catenin associates with a cytosolic and multi-protein destruction complex where it is phosphorylated and targeted for proteasomal degradation. In the presence of Wnt, the destruction complex is inactivated and β-catenin translocates into the nucleus. In the nucleus, β-catenin binds T-cell factor (TCF) transcription factors to activate expression of c-MYC (MYC) and Axis inhibition protein 2 (AXIN2). AXIN2 is a member of the destruction complex and, thus, serves in a negative feedback loop to control Wnt/β-catenin signaling. AXIN2 is also present in the nucleus, but its function within this compartment is unknown. Here, we demonstrate that AXIN2 localizes to the nuclei of epithelial cells within normal and colonic tumor tissues as well as colorectal cancer cell lines. In the nucleus, AXIN2 represses expression of Wnt/β-catenin-responsive luciferase reporters and forms a complex with β-catenin and TCF. We demonstrate that AXIN2 co-occupies β-catenin/TCF complexes at the MYC promoter region. When constitutively localized to the nucleus, AXIN2 alters the chromatin structure at the MYC promoter and directly represses MYC gene expression. These findings suggest that nuclear AXIN2 functions as a rheostat to control MYC expression in response to Wnt/β-catenin signaling

  7. AMPK promotes survival of c-Myc-positive melanoma cells by suppressing oxidative stress.

    Science.gov (United States)

    Kfoury, Alain; Armaro, Marzia; Collodet, Caterina; Sordet-Dessimoz, Jessica; Giner, Maria Pilar; Christen, Stefan; Moco, Sofia; Leleu, Marion; de Leval, Laurence; Koch, Ute; Trumpp, Andreas; Sakamoto, Kei; Beermann, Friedrich; Radtke, Freddy

    2018-03-01

    Although c-Myc is essential for melanocyte development, its role in cutaneous melanoma, the most aggressive skin cancer, is only partly understood. Here we used the Nras Q61K INK4a -/- mouse melanoma model to show that c-Myc is essential for tumor initiation, maintenance, and metastasis. c-Myc-expressing melanoma cells were preferentially found at metastatic sites, correlated with increased tumor aggressiveness and high tumor initiation potential. Abrogation of c-Myc caused apoptosis in primary murine and human melanoma cells. Mechanistically, c-Myc-positive melanoma cells activated and became dependent on the metabolic energy sensor AMP-activated protein kinase (AMPK), a metabolic checkpoint kinase that plays an important role in energy and redox homeostasis under stress conditions. AMPK pathway inhibition caused apoptosis of c-Myc-expressing melanoma cells, while AMPK activation protected against cell death of c-Myc-depleted melanoma cells through suppression of oxidative stress. Furthermore, TCGA database analysis of early-stage human melanoma samples revealed an inverse correlation between C-MYC and patient survival, suggesting that C-MYC expression levels could serve as a prognostic marker for early-stage disease. © 2018 The Authors.

  8. Lanatoside C inhibits cell proliferation and induces apoptosis through attenuating Wnt/β-catenin/c-Myc signaling pathway in human gastric cancer cell.

    Science.gov (United States)

    Hu, Yudong; Yu, Kaikai; Wang, Gang; Zhang, Depeng; Shi, Chaoji; Ding, Yunhe; Hong, Duo; Zhang, Dan; He, Huiqiong; Sun, Lei; Zheng, Jun-Nian; Sun, Shuyang; Qian, Feng

    2018-04-01

    Gastric cancer is the third common cause of cancer mortality in the world with poor prognosis and high recurrence due to lack of effective medicines. Our studies revealed that lanatoside C, a FDA-approved cardiac glycoside, had an anti-proliferation effect on different human cancer cell lines (MKN-45; SGC-7901; HN4; MCF-7; HepG2) and gastric cell lines MKN-45 and SGC-7901 were the most sensitive cell lines to lanatoside C. MKN-45 cells treated with lanatoside C showed cell cycle arrest at G2/M phase and inhibition of cell migration. Meanwhile, upregulation of cleaved caspase-9 and cleaved PARP and downregulation of Bcl-xl were accompanied with the loss of mitochondrial membrane potential (MMP) and induction of intracellular reactive oxygen species (ROS). Lanatoside C inhibited Wnt/β-catenin signaling with downregulation of c-Myc, while overexpression of c-Myc reversed the anti-tumor effect of lanatoside C, confirming that c-Myc is a key drug target of lanatoside C. Furthermore, we discovered that lanatoside C prompted c-Myc degradation in proteasome-ubiquitin pathway with attenuating the binding of USP28 to c-Myc. These findings indicate that lanatoside C targeted c-Myc ubiquitination to inhibit MKN-45 proliferation and support the potential value of lanatoside C as a chemotherapeutic candidate. Copyright © 2018 Elsevier Inc. All rights reserved.

  9. Expression of c-myc and c-fos and binding sites for estradiol and progesterone in human pituitary tumors.

    Science.gov (United States)

    Machiavelli, G A; Rivolta, C M; Artese, R; Basso, A; Burdman, J A

    1998-12-01

    We studied the concentration of mRNA from the oncogenes c-myc and c-fos in human pituitary adenomas by Northern blot hybridization (35 somatotrophinomas, 9 prolactinomas, 21 nonsecreting and 3 adrenocorticotrophinomas). The concentration of estrogens and progesterone receptors was also investigated. The levels of c-myc and c-fos mRNA was higher in nonsecreting tumors which were generally the largest and had a higher percentage of recurrence after surgery than the other groups. High concentration of estrogen receptors was observed in tumors derived from cells which are normally the target of this hormone, mainly prolactinomas. They were also present in somatotrophic and nonsecreting adenomas, related to the presence of prolactin or gonadotrophin cells in these tumors. The presence of estrogen receptors indicates that the tumor cells maintain their differentiation and a good prognosis as is the case for prolactinomas. We did not find any relationship between estrogen receptors and the concentration of c-myc and c-fos oncogenes. Larger adenomas (mainly nonsecreting) had higher levels of c-myc and c-fos mRNA than the other tumors and they had an important percentage of recurrence after surgery. It is clear that tumor size is related to the outcome after surgery and that nonsecreting adenomas are usually large because of the late diagnosis. However two large somatotrophinomas with extrasellar expansion also had overexpression of both oncogenes and both relapsed after surgery.

  10. Drosophila Myc is required for normal DREF gene expression

    International Nuclear Information System (INIS)

    Dang Thi Phuong Thao; Seto, Hirokazu; Yamaguchi, Masamitsu

    2008-01-01

    The Drosophila DNA replication-related element-binding factor (dDREF) is required for the expression of many proliferation-related genes carrying the DRE sequence, 5'-TATCGATA. Finding a canonical E-box, 5'-CACGTG, in the dDREF gene promoter prompted us to explore the possibility that the dDREF gene is a target of Drosophila Myc (dMyc). Luciferase transient expression assays combined with RNA interference in Drosophila S2 cells revealed that knockdown of dmyc reduced dDREF gene promoter activity by 35% to 82%, an effect at least partly mediated by the E-box in the promoter. dm 4 /Y hemizygous mutant larvae demonstrated no maternal dMyc and severe impairment of dDREF mRNA transcription. dMyc loss of function in dm 2 /dm 2 homozygous mutant follicle cell clones also resulted in loss of anti-dDREF immunostaining in nuclei. In contrast, co-expression of dMyc-dMax up-regulated dDREF promoter activity in S2 cells. Furthermore, dMyc over-expressing clones exhibited a high level of dDREF gene expression in wing and eye discs. These results taken together indicate that dMyc is indeed required for dDREF gene expression

  11. Gamabufotalin triggers c-Myc degradation via induction of WWP2 in multiple myeloma cells.

    Science.gov (United States)

    Yu, Zhenlong; Li, Tao; Wang, Chao; Deng, Sa; Zhang, Baojing; Huo, Xiaokui; Zhang, Bo; Wang, Xiaobo; Zhong, Yuping; Ma, Xiaochi

    2016-03-29

    Deciding appropriate therapy for multiple myeloma (MM) is challenging because of the occurrence of multiple chromosomal changes and the fatal nature of the disease. In the current study, gamabufotalin (GBT) was isolated from toad venom, and its tumor-specific cytotoxicity was investigated in human MM cells. We found GBT inhibited cell growth and induced apoptosis with the IC50 values <50 nM. Mechanistic studies using functional approaches identified GBT as an inhibitor of c-Myc. Further analysis showed that GBT especially evoked the ubiquitination and degradation of c-Myc protein, thereby globally repressing the expression of c-Myc target genes. GBT treatment inhibited ERK and AKT signals, while stimulating the activation of JNK cascade. An E3 ubiquitin-protein ligase, WWP2, was upregulated following JNK activation and played an important role in c-Myc ubiquitination and degradation through direct protein-protein interaction. The antitumor effect of GBT was validated in a xenograft mouse model and the suppression of MM-induced osteolysis was verified in a SCID-hu model in vivo. Taken together, our study identified the potential of GBT as a promising therapeutic agent in the treatment of MM.

  12. Targeting c-Myc: JQ1 as a promising option for c-Myc-amplified esophageal squamous cell carcinoma.

    Science.gov (United States)

    Wang, Jingyuan; Liu, Zhentao; Wang, Ziqi; Wang, Shubin; Chen, Zuhua; Li, Zhongwu; Zhang, Mengqi; Zou, Jianling; Dong, Bin; Gao, Jing; Shen, Lin

    2018-04-10

    c-Myc amplification-induced cell cycle dysregulation is a common cause for esophageal squamous cell carcinoma (ESCC), but no approved targeted drug is available so far. The bromodomain inhibitor JQ1, which targets c-Myc, exerts anti-tumor activity in multiple cancers. However, the role of JQ1 in ESCC remains unknown. In this study, we reported that JQ1 had potent anti-proliferative effects on ESCC cells in both time- and dose-dependent manners by inducing cell cycle arrest at G1 phase, cell apoptosis, and the mesenchymal-epithelial transition. Follow-up studies revealed that both c-Myc/cyclin/Rb and PI3K/AKT signaling pathways were inactivated by JQ1, as indicated by the downregulation of c-Myc, cyclin A/E, and phosphorylated Rb, AKT and S6. Tumor suppression induced by JQ1 in c-Myc amplified or highly expressed xenografts was higher than that in xenografts with low expression, suggesting its potential role in prediction. In conclusion, targeting c-Myc by JQ1 could cause significant tumor suppression in ESCC both in vitro and in vivo. Also, c-Myc amplification or high expression might serve as a potential biomarker and provide a promising therapeutic option for ESCC. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. Transformation of follicular lymphoma to plasmablastic lymphoma with c-myc gene rearrangement.

    Science.gov (United States)

    Ouansafi, Ihsane; He, Bing; Fraser, Cory; Nie, Kui; Mathew, Susan; Bhanji, Rumina; Hoda, Rana; Arabadjief, Melissa; Knowles, Daniel; Cerutti, Andrea; Orazi, Attilio; Tam, Wayne

    2010-12-01

    Follicular lymphoma (FL) is an indolent lymphoma that transforms to high-grade lymphoma, mostly diffuse large B-cell lymphoma, in about a third of patients. We present the first report of a case of FL that transformed to plasmablastic lymphoma (PBL). Clonal transformation of the FL to PBL was evidenced by identical IGH/BCL2 gene rearrangements and VDJ gene usage in rearranged IGH genes. IGH/ BCL2 translocation was retained in the PBL, which also acquired c-myc gene rearrangement. Genealogic analysis based on somatic hypermutation of the rearranged IGH genes of both FL and PBL suggests that transformation of the FL to PBL occurred most likely by divergent evolution from a common progenitor cell rather than direct evolution from the FL clone. Our study of this unusual case expands the histologic spectrum of FL transformation and increases our understanding of the pathogenetic mechanisms of transformation of indolent lymphomas to aggressive lymphomas.

  14. The small Rho GTPase Rac1 controls normal human dermal fibroblasts proliferation with phosphorylation of the oncoprotein c-myc

    International Nuclear Information System (INIS)

    Nikolova, Ekaterina; Mitev, Vanio; Zhelev, Nikolai; Deroanne, Christophe F.; Poumay, Yves

    2007-01-01

    Proliferation of dermal fibroblasts is crucial for the maintenance of skin. The small Rho GTPase, Rac1, has been identified as a key transducer of proliferative signals in various cell types, but in normal human dermal fibroblasts its significance to cell growth control has not been studied. In this study, we applied the method of RNA interference to suppress endogenous Rac1 expression and examined the consequences on human skin fibroblasts. Rac1 knock-down resulted in inhibition of DNA synthesis. This effect was not mediated by inhibition of the central transducer of proliferative stimuli, ERK1/2 or by activation of the pro-apoptotic p38. Rather, as a consequence of the suppressed Rac1 expression we observed a significant decrease in phosphorylation of c-myc, revealing for the first time that in human fibroblasts Rac1 exerts control on proliferation through c-myc phosphorylation. Thus Rac1 activates proliferation of normal fibroblasts through stimulation of c-myc phosphorylation without affecting ERK1/2 activity

  15. Profiling and bioinformatic analysis of circular RNA expression regulated by c-Myc.

    Science.gov (United States)

    Gou, Qiheng; Wu, Ke; Zhou, Jian-Kang; Xie, Yuxin; Liu, Lunxu; Peng, Yong

    2017-09-22

    The c-Myc transcription factor is involved in cell proliferation, cell cycle and apoptosis by activating or repressing transcription of multiple genes. Circular RNAs (circRNAs) are widely expressed non-coding RNAs participating in the regulation of gene expression. Using a high-throughput microarray assay, we showed that Myc regulates the expression of certain circRNAs. A total of 309 up- and 252 down-regulated circRNAs were identified. Among them, randomly selected 8 circRNAs were confirmed by real-time PCR. Subsequently, Myc-binding sites were found to generally exist in the promoter regions of differentially expressed circRNAs. Based on miRNA sponge mechanism, we constructed circRNAs/miRNAs network regulated by Myc, suggesting that circRNAs may widely regulate protein expression through miRNA sponge mechanism. Lastly, we took advantage of Gene Ontology and KEGG analyses to point out that Myc-regulated circRNAs could impact cell proliferation through affecting Ras signaling pathway and pathways in cancer. Our study for the first time demonstrated that Myc transcription factor regulates the expression of circRNAs, adding a novel component of the Myc tumorigenic program and opening a window to investigate the function of certain circRNAs in tumorigenesis.

  16. NM23-H2 may play an indirect role in transcriptional activation of c-myc gene expression but does not cleave the nuclease hypersensitive element III1

    International Nuclear Information System (INIS)

    Dexheimer, Thomas S.; Carey, Steven S.; Zuohe, Song; Gokhale, Vijay M.; Hu, Xiaohui; Murata, Lauren B.; Maes, Estelle M.; Weichsel, Andrzej; Sun, Daekyu; Meuillet, Emmanuelle J.; Montfort, William R.; Hurley, Laurence H.

    2009-01-01

    The formation of G-quadruplex structures within the nuclease hypersensitive element (NHE) III 1 region of the c-myc promoter and the ability of these structures to repress c-myc transcription have been well established. However, just how these extremely stable DNA secondary structures are transformed to activate c-myc transcription is still unknown. NM23-H2/nucleoside diphosphate kinase B has been recognized as an activator of c-myc transcription via interactions with the NHE III 1 region of the c-myc gene promoter. Through the use of RNA interference, we confirmed the transcriptional regulatory role of NM23-H2. In addition, we find that further purification of NM23-H2 results in loss of the previously identified DNA strand cleavage activity, but retention of its DNA binding activity. NM23-H2 binds to both single-stranded guanine- and cytosine-rich strands of the c-myc NHE III 1 and, to a lesser extent, to a random single-stranded DNA template. However, it does not bind to or cleave the NHE III 1 in duplex form. Significantly, potassium ions and compounds that stabilize the G-quadruplex and i-motif structures have an inhibitory effect on NM23-H2 DNA-binding activity. Mutation of Arg 88 to Ala 88 (R88A) reduced both DNA and nucleotide binding but had minimal effect on the NM23-H2 crystal structure. On the basis of these data and molecular modeling studies, we have proposed a stepwise trapping-out of the NHE III 1 region in a single-stranded form, thus allowing single-stranded transcription factors to bind and activate c-myc transcription. Furthermore, this model provides a rationale for how the stabilization of the G-quadruplex or i-motif structures formed within the c-myc gene promoter region can inhibit NM23-H2 from activating c-myc gene expression.

  17. The Max b-HLH-LZ can transduce into cells and inhibit c-Myc transcriptional activities.

    Directory of Open Access Journals (Sweden)

    Martin Montagne

    Full Text Available The inhibition of the functions of c-Myc (endogenous and oncogenic was recently shown to provide a spectacular therapeutic index in cancer mouse models, with complete tumor regression and minimal side-effects in normal tissues. This was achieved by the systemic and conditional expression of omomyc, the cDNA of a designed mutant of the b-HLH-LZ of c-Myc named Omomyc. The overall mode of action of Omomyc consists in the sequestration of Max and the concomitant competition of the Omomyc/Max complex with the endogenous c-Myc/Max heterodimer. This leads to the inhibition of the transactivation of Myc target genes involved in proliferation and metabolism. While this body of work has provided extraordinary insights to guide the future development of new cancer therapies that target c-Myc, Omomyc itself is not a therapeutic agent. In this context, we sought to exploit the use of a b-HLH-LZ to inhibit c-Myc in a cancer cell line in a more direct fashion. We demonstrate that the b-HLH-LZ domain of Max (Max* behaves as a bona fide protein transduction domain (PTD that can efficiently transduce across cellular membrane via through endocytosis and translocate to the nucleus. In addition, we show that the treatment of HeLa cells with Max* leads to a reduction of metabolism and proliferation rate. Accordingly, we observe a decrease of the population of HeLa cells in S phase, an accumulation in G1/G0 and the induction of apoptosis. In agreement with these phenotypic changes, we show by q-RT-PCR that the treatment of HeLa cells with Max* leads to the activation of the transcription c-Myc repressed genes as well as the repression of the expression of c-Myc activated genes. In addition to the novel discovery that the Max b-HLH-LZ is a PTD, our findings open up new avenues and strategies for the direct inhibition of c-Myc with b-HLH-LZ analogs.

  18. Relationship of Amplification and Expression of the C-MYC Gene with Survival among Gastric Cancer Patients.

    Science.gov (United States)

    Khaleghian, Malihea; Shakoori, Abbas; Razavi, Amirnader Emami; Azimi, Cyrus

    2015-01-01

    During the past decades, the incidence and mortality rate of stomach cancer has demonstrated a great decrease in the world, but it is still one of the most common and fatal cancers especially among men worldwide, including Iran. The MYC proto-oncogene, which is located at 8q24.1, regulates 15% of genes and is activated in 20% of all human tumors. MYC amplification and overexpression of its protein product has been reported in 15-30% of gastric neoplasias. The aim of this investigation was to find the relative efficacy of CISH (chromogenic in situ hybridization) or IHC (immunohistochemistry) in diagnosis and prognosis of gastric cancer, as well as the relationship of amplification and expression of C-MYC gene with patient survival. In this cross-sectional study, 102 samples of gastric cancer were collected from patients who had undergone primary surgical resection at the Cancer Institute Hospital, Tehran University of Medical Sciences, from July 2009 to March 2014. All samples were randomly selected from those who were diagnosed with gastric adenocarcinomas. CISH and IHC methods were performed on all of them. Patients were classified into two groups. The first consisted of stage I and II cases, and the second of stage III and IV. Survival tests for both groups was carried out with referrnce to CISH test reults. Group II (stage III and IV) with CISH+ featured lower survival than those with CISH- (p=0.233), but group I (stage I and II) patients demonstrated no significant variation with CISH+ or CISH- (p=0.630). Kaplan-Meier for both groups was carried out with IHC test findings and showed similar results. This data revealed that both diffuse and intestinal types of gastric cancer occurred significantly more in men than women. Our data also showed that CISH+ patients (43%) were more frequent in comparison with IHC+ patients (14.7%). For planning treatment of gastric cancer patients, by focusing on expanding tumors, which is the greatest concern of the surgeons and

  19. Disruption of MEK/ERK/c-Myc signaling radiosensitizes prostate cancer cells in vitro and in vivo.

    Science.gov (United States)

    Ciccarelli, Carmela; Di Rocco, Agnese; Gravina, Giovanni Luca; Mauro, Annunziata; Festuccia, Claudio; Del Fattore, Andrea; Berardinelli, Paolo; De Felice, Francesca; Musio, Daniela; Bouché, Marina; Tombolini, Vincenzo; Zani, Bianca Maria; Marampon, Francesco

    2018-06-29

    Prostate cancer (PCa) cell radioresistance causes the failure of radiation therapy (RT) in localized or locally advanced disease. The aberrant accumulation of c-Myc oncoprotein, known to promote PCa onset and progression, may be due to the control of gene transcription and/or MEK/ERK-regulated protein stabilization. Here, we investigated the role of MEK/ERK signaling in PCa. LnCAP, 22Rv1, DU145, and PC3 PCa cell lines were used in in vitro and in vivo experiments. U0126, trametinib MEK/ERK inhibitors, and c-Myc shRNAs were used. Radiation was delivered using an x-6 MV photon linear accelerator. U0126 in vivo activity alone or in combination with irradiation was determined in murine xenografts. Inhibition of MEK/ERK signaling down-regulated c-Myc protein in PCa cell lines to varying extents by affecting expression of RNA and protein, which in turn determined radiosensitization in in vitro and in vivo xenograft models of PCa cells. The crucial role played by c-Myc in the MEK/ERK pathways was demonstrated in 22Rv1 cells by the silencing of c-Myc by means of short hairpin mRNA, which yielded effects resembling the targeting of MEK/ERK signaling. The clinically approved compound trametinib used in vitro yielded the same effects as U0126 on growth and C-Myc expression. Notably, U0126 and trametinib induced a drastic down-regulation of BMX, which is known to prevent apoptosis in cancer cells. The results of our study suggest that signal transduction-based therapy can, by disrupting the MEK/ERK/c-Myc axis, reduce human PCa radioresistance caused by increased c-Myc expression in vivo and in vitro and restores apoptosis signals.

  20. NCYM promotes calpain-mediated Myc-nick production in human MYCN-amplified neuroblastoma cells

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    Shoji, Wataru [Division of Biochemistry and Innovative Cancer Therapeutics and Children' s Cancer Research Center, Chiba Cancer Center Research Institute, 666-2 Nitona, Chuo-ku, Chiba 260-8717 (Japan); Department of Pediatric Surgery, Graduate School of Medicine, Tohoku University, Sendai 980-8574 (Japan); Suenaga, Yusuke, E-mail: ysuenaga@chiba-cc.jp [Division of Biochemistry and Innovative Cancer Therapeutics and Children' s Cancer Research Center, Chiba Cancer Center Research Institute, 666-2 Nitona, Chuo-ku, Chiba 260-8717 (Japan); Cancer Genome Center, Chiba Cancer Center Research Institute, 666-2 Nitona, Chuo-ku, Chiba 260-8717 (Japan); Kaneko, Yoshiki; Islam, S.M. Rafiqul; Alagu, Jennifer [Division of Biochemistry and Innovative Cancer Therapeutics and Children' s Cancer Research Center, Chiba Cancer Center Research Institute, 666-2 Nitona, Chuo-ku, Chiba 260-8717 (Japan); Yokoi, Sana [Cancer Genome Center, Chiba Cancer Center Research Institute, 666-2 Nitona, Chuo-ku, Chiba 260-8717 (Japan); Nio, Masaki [Department of Pediatric Surgery, Graduate School of Medicine, Tohoku University, Sendai 980-8574 (Japan); Nakagawara, Akira, E-mail: nakagawara-a@koseikan.jp [Division of Biochemistry and Innovative Cancer Therapeutics and Children' s Cancer Research Center, Chiba Cancer Center Research Institute, 666-2 Nitona, Chuo-ku, Chiba 260-8717 (Japan)

    2015-06-05

    NCYM is a cis-antisense gene of MYCN and is amplified in human neuroblastomas. High NCYM expression is associated with poor prognoses, and the NCYM protein stabilizes MYCN to promote proliferation of neuroblastoma cells. However, the molecular mechanisms of NCYM in the regulation of cell survival have remained poorly characterized. Here we show that NCYM promotes cleavage of MYCN to produce the anti-apoptotic protein, Myc-nick, both in vitro and in vivo. NCYM and Myc-nick were induced at G2/M phase, and NCYM knockdown induced apoptotic cell death accompanied by Myc-nick downregulation. These results reveal a novel function of NCYM as a regulator of Myc-nick production in human neuroblastomas. - Highlights: • NCYM promotes cleavages of MYC and MYCN to produce Myc-nick in vitro. • NCYM increases Myc-nick production in MYCN-amplified neuroblastoma cells. • NCYM knockdown decreases Myc-nick production and induces apoptosis at G2/M phase.

  1. NCYM promotes calpain-mediated Myc-nick production in human MYCN-amplified neuroblastoma cells

    International Nuclear Information System (INIS)

    Shoji, Wataru; Suenaga, Yusuke; Kaneko, Yoshiki; Islam, S.M. Rafiqul; Alagu, Jennifer; Yokoi, Sana; Nio, Masaki; Nakagawara, Akira

    2015-01-01

    NCYM is a cis-antisense gene of MYCN and is amplified in human neuroblastomas. High NCYM expression is associated with poor prognoses, and the NCYM protein stabilizes MYCN to promote proliferation of neuroblastoma cells. However, the molecular mechanisms of NCYM in the regulation of cell survival have remained poorly characterized. Here we show that NCYM promotes cleavage of MYCN to produce the anti-apoptotic protein, Myc-nick, both in vitro and in vivo. NCYM and Myc-nick were induced at G2/M phase, and NCYM knockdown induced apoptotic cell death accompanied by Myc-nick downregulation. These results reveal a novel function of NCYM as a regulator of Myc-nick production in human neuroblastomas. - Highlights: • NCYM promotes cleavages of MYC and MYCN to produce Myc-nick in vitro. • NCYM increases Myc-nick production in MYCN-amplified neuroblastoma cells. • NCYM knockdown decreases Myc-nick production and induces apoptosis at G2/M phase

  2. c-Myc over-expression in Ramos Burkitt's lymphoma cell line predisposes to iron homeostasis disruption in vitro

    International Nuclear Information System (INIS)

    Habel, Marie-Eve; Jung, Daniel

    2006-01-01

    Burkitt's lymphoma is an aggressive B-cell neoplasm resulting from deregulated c-myc expression. We have previously shown that proliferation of Burkitt's lymphoma cell lines such as Ramos is markedly reduced by iron treatment. It has been shown that iron induces expression of c-myc which, owing to its transcriptional regulatory functions, regulates genes involved in iron metabolism. Transient enhancement of c-myc expression by iron could increase the expression of genes involved in iron incorporation, which could lead to an accumulation of intracellular free iron. Here, we have investigated whether cells with a high basal level of c-Myc were more likely to accumulate free iron. Our results suggest that the basal level of c-Myc in Ramos cells is twofold higher than what is seen in HL-60 cells. Moreover, in Ramos cells, where c-Myc is expressed at a high level, H-ferritin expression is down-regulated, transferrin receptor (CD71) expression is increased, and ferritin translation is inhibited. These modifications in iron metabolism, resulting from the strong basal expression of c-Myc, and amplified by iron addition, could lead to a disruption in homeostasis and consequently to growth arrest

  3. Targeted repression of AXIN2 and MYC gene expression using designer TALEs

    International Nuclear Information System (INIS)

    Rennoll, Sherri A.; Scott, Samantha A.; Yochum, Gregory S.

    2014-01-01

    Highlights: • We designed TALE–SID fusion proteins to target AXIN2 and MYC. • TALE–SIDs bound the chromosomal AXIN2 and MYC genes and repressed their expression. • TALE–SIDs repress β-catenin S45F -dependent AXIN2 and MYC transcription. - Abstract: Designer TALEs (dTALEs) are chimeric transcription factors that can be engineered to regulate gene expression in mammalian cells. Whether dTALEs can block gene transcription downstream of signal transduction cascades, however, has yet to be fully explored. Here we tested whether dTALEs can be used to target genes whose expression is controlled by Wnt/β-catenin signaling. TALE DNA binding domains were engineered to recognize sequences adjacent to Wnt responsive enhancer elements (WREs) that control expression of axis inhibition protein 2 (AXIN2) and c-MYC (MYC). These custom DNA binding domains were linked to the mSin3A interaction domain (SID) to generate TALE–SID chimeric repressors. The TALE–SIDs repressed luciferase reporter activity, bound their genomic target sites, and repressed AXIN2 and MYC expression in HEK293 cells. We generated a novel HEK293 cell line to determine whether the TALE–SIDs could function downstream of oncogenic Wnt/β-catenin signaling. Treating these cells with doxycycline and tamoxifen stimulates nuclear accumulation of a stabilized form of β-catenin found in a subset of colorectal cancers. The TALE–SIDs repressed AXIN2 and MYC expression in these cells, which suggests that dTALEs could offer an effective therapeutic strategy for the treatment of colorectal cancer

  4. Targeted repression of AXIN2 and MYC gene expression using designer TALEs

    Energy Technology Data Exchange (ETDEWEB)

    Rennoll, Sherri A.; Scott, Samantha A.; Yochum, Gregory S., E-mail: gsy3@psu.edu

    2014-04-18

    Highlights: • We designed TALE–SID fusion proteins to target AXIN2 and MYC. • TALE–SIDs bound the chromosomal AXIN2 and MYC genes and repressed their expression. • TALE–SIDs repress β-catenin{sup S45F}-dependent AXIN2 and MYC transcription. - Abstract: Designer TALEs (dTALEs) are chimeric transcription factors that can be engineered to regulate gene expression in mammalian cells. Whether dTALEs can block gene transcription downstream of signal transduction cascades, however, has yet to be fully explored. Here we tested whether dTALEs can be used to target genes whose expression is controlled by Wnt/β-catenin signaling. TALE DNA binding domains were engineered to recognize sequences adjacent to Wnt responsive enhancer elements (WREs) that control expression of axis inhibition protein 2 (AXIN2) and c-MYC (MYC). These custom DNA binding domains were linked to the mSin3A interaction domain (SID) to generate TALE–SID chimeric repressors. The TALE–SIDs repressed luciferase reporter activity, bound their genomic target sites, and repressed AXIN2 and MYC expression in HEK293 cells. We generated a novel HEK293 cell line to determine whether the TALE–SIDs could function downstream of oncogenic Wnt/β-catenin signaling. Treating these cells with doxycycline and tamoxifen stimulates nuclear accumulation of a stabilized form of β-catenin found in a subset of colorectal cancers. The TALE–SIDs repressed AXIN2 and MYC expression in these cells, which suggests that dTALEs could offer an effective therapeutic strategy for the treatment of colorectal cancer.

  5. Multiple fractions of gamma rays do not induce overexpression of c-myc or c-Ki-ras oncogenes in human cervical carcinoma cells

    International Nuclear Information System (INIS)

    Osmak, M.; Soric, J.; Matulic, M.

    1993-01-01

    Multiple fractions of gamma rays (0.5 Gy daily, 30 fractions) had previously been found to change the sensitivity of human cervical carcinoma HeLa cells to anticancer drugs. Preirradiated cells became resistant to cisplatin, methotrexate and vincristine but retained the same sensitivity to gamma rays and ultraviolet light. Some mechanisms involved in the resistance of preirradiated cells to cisplatin and vincristine were determined, i.e. the increased levels of metallothioneins and increased expression of plasma membrane P glycoprotein. As recent reports indicated that the resistance to cisplatin and ionizing radiation may involve the expression of oncogenes, the problem was studied whether multiple fractions of gamma rays can change the expression of c-myc and c-Ki-ras oncogenes in HeLa cells and whether there is a correlation between the expression of these oncogenes and the sensitivity of preirradiated cells to cisplatin and gamma rays. The expression of c-myc and c-Ki-ras oncogenes was examined using the DNA dot blot, the RNA dot blot and Northern blot analysis. The results show that preirradiation induced neither amplification nor elevated expression of c-myc and c-Ki-ras oncogenes. Furthermore, there is no correlation between the expression of c-myc and c-Ki-ras oncogenes and the acquired resistance to cisplatin. (author) 3 figs., 32 refs

  6. [Survival of patients with primary central nervous system diffuse large B-cell lymphoma: impact of gene aberrations and protein overexpression of bcl-2 and C-MYC, and selection of chemotherapy regimens].

    Science.gov (United States)

    Yin, W J; Zhu, X; Yang, H Y; Sun, W Y; Wu, M J

    2018-01-08

    Objective: To investigate the impact of clinicopathological features, gene rearrangements and protein expression of bcl-6, bcl-2, C-MYC and chemotherapy regime on the prognosis of patients with primary central nervous system diffuse large B-cell lymphoma (PCNS-DLBCL). Methods: Thirty-three cases of PCNS-DLBCL diagnosed from January 2006 to December 2016 at Zhejiang Cancer Hospital were collected. The expression of CD10, bcl-6, bcl-2, MUM1 and MYC were detected by immunohistochemical staining (IHC). The presence of EB virus was detected by in situ hybridization(EBER). Copy number variation (ICN) and translocation status of bcl-6, bcl-2 and C-MYC genes were detected by fluorescence in situ hybridization (FISH). The relationship between the above indexes and the prognosis was analyzed by univariate, bivariate survival analysis and multiple Cox hazard regression analysis. Results: The study included 33 patients of PCNS-DLBCL, without evidence of primary or secondary immunodeficient disease. Male to female ratio was 1.36∶1.00, and the average age was 56 years. Twenty cases had single lesion while 13 had multiple lesions. Deep brain involvement was seen in 12 cases. All patients underwent partial or total tumor resection. Five patients received whole brain post-surgery radiotherapy, nine patients received high-dose methotrexate (HD-MTX) based chemotherapy, and 12 patients received whole-brain radiotherapy combined with HD-MTX based chemotherapy. Severn patients received no further treatment and rituximab was used in 8 patients. According to the Hans model, 27 cases were classified as non-GCB subtypes (81.8%). Bcl-2 was positive in 25 cases (75.8%, 25/33) and highly expressed in 8 (24.2%). MYC was positive in 12 cases (36.4%) and double expression of bcl-2 and MYC was seen in 6 cases. EBER positive rate was 10.0%(3/30), all of which had multiple lesions. Two bcl-6 gene translocations and 3 amplifications were found in 28 patients. Two translocations, 3 ICN or with both

  7. Pre-clinical analysis of changes in intra-cellular biochemistry of glioblastoma multiforme (GBM) cells due to c-Myc silencing.

    Science.gov (United States)

    Rajagopalan, Vishal; Vaidyanathan, Muthukumar; Janardhanam, Vanisree Arambakkam; Bradner, James E

    2014-10-01

    Glioblastoma Multiforme (GBM) is an aggressive form of brain Tumor that has few cures. In this study, we analyze the anti-proliferative effects of a new molecule JQ1 against GBMs induced in Wistar Rats. JQ1 is essentially a Myc inhibitor. c-Myc is also known for altering the biochemistry of a tumor cell. Therefore, the study is intended to analyze certain other oncogenes associated with c-Myc and also the change in cellular biochemistry upon c-Myc inhibition. The quantitative analysis of gene expression gave a co-expressive pattern for all the three genes involved namely; c-Myc, Bcl-2, and Akt. The cellular biochemistry analysis by transmission electron microscopy revealed high glycogen and lipid aggregation in Myc inhibited cells and excessive autophagy. The study demonstrates the role of c-Myc as a central metabolic regulator and Bcl-2 and Akt assisting in extending c-Myc half-life as well as in regulation of autophagy, so as to regulate cell survival on the whole. The study also demonstrates that transient treatment by JQ1 leads to aggressive development of tumor and therefore, accelerating death, emphasizing the importance of dosage fixation, and duration for clinical use in future.

  8. Interrelationship between chromosome 8 aneuploidy, C-MYC amplification and increased expression in individuals from northern Brazil with gastric adenocarcinoma

    Science.gov (United States)

    Calcagno, Danielle Queiroz; Leal, Mariana Ferreira; Seabra, Aline Damaceno; Khayat, André Salim; Chen, Elizabeth Suchi; Demachki, Samia; Assumpção, Paulo Pimentel; Faria, Mario Henrique Girão; Rabenhorst, Silvia Helena Barem; Ferreira, Márcia Valéria Pitombeira; Smith, Marília de Arruda Cardoso; Burbano, Rommel Rodríguez

    2006-01-01

    AIM: To investigate chromosome 8 numerical aberrations, C-MYC oncogene alterations and its expression in gastric cancer and to correlate these findings with histopathological characteristics of gastric tumors. METHODS: Specimens were collected surgically from seven patients with gastric adenocarcinomas. Immunostaining for C-MYC and dual-color fluorescence in situ hybridization (FISH) for C-MYC gene and chromosome 8 centromere were performed. RESULTS: All the cases showed chromosome 8 aneuploidy and C-MYC amplification, in both the diffuse and intestinal histopathological types of Lauren. No significant difference (P < 0.05) was observed between the level of chromosome 8 ploidy and the site, stage or histological type of the adenocarcinomas. C-MYC high amplification, like homogeneously stained regions (HSRs) and double minutes (DMs), was observed only in the intestinal-type. Structural rearrangement of C-MYC, like translocation, was observed only in the diffuse type. Regarding C-MYC gene, a significant difference (P < 0.05) was observed between the two histological types. The C-MYC protein was expressed in all the studied cases. In the intestinal-type the C-MYC immunoreactivity was localized only in the nucleus and in the diffuse type in the nucleus and cytoplasm. CONCLUSION: Distinct patterns of alterations between intestinal and diffuse types of gastric tumors support the hypothesis that these types follow different genetic pathways. PMID:17036397

  9. MYC association with cancer risk and a new model of MYC-mediated repression.

    Science.gov (United States)

    Cole, Michael D

    2014-07-01

    MYC is one of the most frequently mutated and overexpressed genes in human cancer but the regulation of MYC expression and the ability of MYC protein to repress cellular genes (including itself) have remained mysterious. Recent genome-wide association studies show that many genetic polymorphisms associated with disease risk map to distal regulatory elements that regulate the MYC promoter through large chromatin loops. Cancer risk-associated single-nucleotide polymorphisms (SNPs) contain more potent enhancer activity, promoting higher MYC levels and a greater risk of disease. The MYC promoter is also subject to complex regulatory circuits and limits its own expression by a feedback loop. A model for MYC autoregulation is discussed which involves a signaling pathway between the PTEN (phosphatase and tensin homolog) tumor suppressor and repressive histone modifications laid down by the EZH2 methyltransferase. Copyright © 2014 Cold Spring Harbor Laboratory Press; all rights reserved.

  10. Reduced expression of N-Myc downstream-regulated gene 2 in human thyroid cancer

    Directory of Open Access Journals (Sweden)

    Ma Jianjun

    2008-10-01

    Full Text Available Abstract Background NDRG2 (N-Myc downstream-regulated gene 2 was initially cloned in our laboratory. Previous results have shown that NDRG2 expressed differentially in normal and cancer tissues. Specifically, NDRG2 mRNA was down-regulated or undetectable in several human cancers, and over-expression of NDRG2 inhibited the proliferation of cancer cells. NDRG2 also exerts important functions in cell differentiation and tumor suppression. However, it remains unclear whether NDRG2 participates in carcinogenesis of the thyroid. Methods In this study, we investigated the expression profile of human NDRG2 in thyroid adenomas and carcinomas, by examining tissues from individuals with thyroid adenomas (n = 40 and carcinomas (n = 35, along with corresponding normal tissues. Immunohistochemistry, quantitative RT-PCR and western blot methods were utilized to determine both the protein and mRNA expression status of Ndrg2 and c-Myc. Results The immunostaining analysis revealed a decrease of Ndrg2 expression in thyroid carcinomas. When comparing adenomas or carcinomas with adjacent normal tissue from the same individual, the mRNA expression level of NDRG2 was significantly decreased in thyroid carcinoma tissues, while there was little difference in adenoma tissues. This differential expression was confirmed at the protein level by western blotting. However, there were no significant correlations of NDRG2 expression with gender, age, different histotypes of thyroid cancers or distant metastases. Conclusion Our data indicates that NDRG2 may participate in thyroid carcinogenesis. This finding provides novel insight into the important role of NDRG2 in the development of thyroid carcinomas. Future studies are needed to address whether the down-regulation of NDRG2 is a cause or a consequence of the progression from a normal thyroid to a carcinoma.

  11. Reduced expression of N-Myc downstream-regulated gene 2 in human thyroid cancer

    International Nuclear Information System (INIS)

    Zhao, Huadong; Chen, Suning; Lin, Wei; Shi, Hai; Ma, Jianjun; Liu, Xinping; Ma, Qingjiu; Yao, Libo; Zhang, Jian; Lu, Jianguo; He, Xianli; Chen, Changsheng; Li, Xiaojun; Gong, Li; Bao, Guoqiang; Fu, Qiang

    2008-01-01

    NDRG2 (N-Myc downstream-regulated gene 2) was initially cloned in our laboratory. Previous results have shown that NDRG2 expressed differentially in normal and cancer tissues. Specifically, NDRG2 mRNA was down-regulated or undetectable in several human cancers, and over-expression of NDRG2 inhibited the proliferation of cancer cells. NDRG2 also exerts important functions in cell differentiation and tumor suppression. However, it remains unclear whether NDRG2 participates in carcinogenesis of the thyroid. In this study, we investigated the expression profile of human NDRG2 in thyroid adenomas and carcinomas, by examining tissues from individuals with thyroid adenomas (n = 40) and carcinomas (n = 35), along with corresponding normal tissues. Immunohistochemistry, quantitative RT-PCR and western blot methods were utilized to determine both the protein and mRNA expression status of Ndrg2 and c-Myc. The immunostaining analysis revealed a decrease of Ndrg2 expression in thyroid carcinomas. When comparing adenomas or carcinomas with adjacent normal tissue from the same individual, the mRNA expression level of NDRG2 was significantly decreased in thyroid carcinoma tissues, while there was little difference in adenoma tissues. This differential expression was confirmed at the protein level by western blotting. However, there were no significant correlations of NDRG2 expression with gender, age, different histotypes of thyroid cancers or distant metastases. Our data indicates that NDRG2 may participate in thyroid carcinogenesis. This finding provides novel insight into the important role of NDRG2 in the development of thyroid carcinomas. Future studies are needed to address whether the down-regulation of NDRG2 is a cause or a consequence of the progression from a normal thyroid to a carcinoma

  12. RNA interference-mediated c-MYC inhibition prevents cell growth and decreases sensitivity to radio- and chemotherapy in childhood medulloblastoma cells

    International Nuclear Information System (INIS)

    Bueren, André O von; Shalaby, Tarek; Oehler-Jänne, Christoph; Arnold, Lucia; Stearns, Duncan; Eberhart, Charles G; Arcaro, Alexandre; Pruschy, Martin; Grotzer, Michael A

    2009-01-01

    With current treatment strategies, nearly half of all medulloblastoma (MB) patients die from progressive tumors. Accordingly, the identification of novel therapeutic strategies remains a major goal. Deregulation of c-MYC is evident in numerous human cancers. In MB, over-expression of c-MYC has been shown to cause anaplasia and correlate with unfavorable prognosis. To study the role of c-MYC in MB biology, we down-regulated c-MYC expression by using small interfering RNA (siRNA) and investigated changes in cellular proliferation, cell cycle analysis, apoptosis, telomere maintenance, and response to ionizing radiation (IR) and chemotherapeutics in a representative panel of human MB cell lines expressing different levels of c-MYC (DAOY wild-type, DAOY transfected with the empty vector, DAOY transfected with c-MYC, D341, and D425). siRNA-mediated c-MYC down-regulation resulted in an inhibition of cellular proliferation and clonogenic growth, inhibition of G1-S phase cell cycle progression, and a decrease in human telomerase reverse transcriptase (hTERT) expression and telomerase activity. On the other hand, down-regulation of c-MYC reduced apoptosis and decreased the sensitivity of human MB cells to IR, cisplatin, and etoposide. This effect was more pronounced in DAOY cells expressing high levels of c-MYC when compared with DAOY wild-type or DAOY cells transfected with the empty vector. In human MB cells, in addition to its roles in growth and proliferation, c-MYC is also a potent inducer of apoptosis. Therefore, targeting c-MYC might be of therapeutic benefit when used sequentially with chemo- and radiotherapy rather than concomitantly

  13. RNA interference-mediated c-MYC inhibition prevents cell growth and decreases sensitivity to radio- and chemotherapy in childhood medulloblastoma cells

    Directory of Open Access Journals (Sweden)

    Arcaro Alexandre

    2009-01-01

    Full Text Available Abstract Background With current treatment strategies, nearly half of all medulloblastoma (MB patients die from progressive tumors. Accordingly, the identification of novel therapeutic strategies remains a major goal. Deregulation of c-MYC is evident in numerous human cancers. In MB, over-expression of c-MYC has been shown to cause anaplasia and correlate with unfavorable prognosis. Methods To study the role of c-MYC in MB biology, we down-regulated c-MYC expression by using small interfering RNA (siRNA and investigated changes in cellular proliferation, cell cycle analysis, apoptosis, telomere maintenance, and response to ionizing radiation (IR and chemotherapeutics in a representative panel of human MB cell lines expressing different levels of c-MYC (DAOY wild-type, DAOY transfected with the empty vector, DAOY transfected with c-MYC, D341, and D425. Results siRNA-mediated c-MYC down-regulation resulted in an inhibition of cellular proliferation and clonogenic growth, inhibition of G1-S phase cell cycle progression, and a decrease in human telomerase reverse transcriptase (hTERT expression and telomerase activity. On the other hand, down-regulation of c-MYC reduced apoptosis and decreased the sensitivity of human MB cells to IR, cisplatin, and etoposide. This effect was more pronounced in DAOY cells expressing high levels of c-MYC when compared with DAOY wild-type or DAOY cells transfected with the empty vector. Conclusion In human MB cells, in addition to its roles in growth and proliferation, c-MYC is also a potent inducer of apoptosis. Therefore, targeting c-MYC might be of therapeutic benefit when used sequentially with chemo- and radiotherapy rather than concomitantly.

  14. Anti-apoptotic A1 is not essential for lymphoma development in Eµ-Myc mice but helps sustain transplanted Eµ-Myc tumour cells.

    Science.gov (United States)

    Mensink, Mark; Anstee, Natasha S; Robati, Mikara; Schenk, Robyn L; Herold, Marco J; Cory, Suzanne; Vandenberg, Cassandra J

    2018-03-01

    The transcription factor c-MYC regulates a multiplicity of genes involved in cellular growth, proliferation, metabolism and DNA damage response and its overexpression is a hallmark of many tumours. Since MYC promotes apoptosis under conditions of stress, such as limited availability of nutrients or cytokines, MYC-driven cells are very much dependent on signals that inhibit cell death. Stress signals trigger apoptosis via the pathway regulated by opposing fractions of the BCL-2 protein family and previous genetic studies have shown that the development of B lymphoid tumours in Eµ-Myc mice is critically dependent on expression of pro-survival BCL-2 relatives MCL-1, BCL-W and, to a lesser extent, BCL-X L , but not BCL-2 itself, and that sustained growth of these lymphomas is dependent on MCL-1. Using recently developed mice that lack expression of all three functional pro-survival A1 genes, we show here that the kinetics of lymphoma development in Eµ-Myc mice and the competitive repopulation capacity of Eµ-Myc haemopoietic stem and progenitor cells is unaffected by the absence of A1. However, conditional loss of a single remaining functional A1 gene from transplanted A1-a -/- A1-b fl/fl A1-c -/- Eµ-Myc lymphomas slowed their expansion, significantly extending the life of the transplant recipients. Thus, A1 contributes to the survival of malignant Eµ-Myc-driven B lymphoid cells. These results strengthen the case for BFL-1, the human homologue of A1, being a valid target for drug development for MYC-driven tumours.

  15. Hsa-let-7a functions as a tumor suppressor in renal cell carcinoma cell lines by targeting c-myc

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yongchao; Yin, Bingde; Zhang, Changcun; Zhou, Libin [Department of Urology, Shanghai First People' s Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200080 (China); Fan, Jie, E-mail: jief67@sina.com [Department of Urology, Shanghai First People' s Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200080 (China)

    2012-01-06

    Highlights: Black-Right-Pointing-Pointer This study is the first to test the let-7a/c-myc loop in renal cell carcinoma cell lines. Black-Right-Pointing-Pointer Let-7a down-regulated c-myc in three renal cell carcinoma cell lines. Black-Right-Pointing-Pointer c-myc target genes were down-regulated because of the let-7a-mediated down-regulation of c-myc. Black-Right-Pointing-Pointer The let-7a/c-myc loop has a significant function in renal cell carcinoma cell lines. -- Abstract: Widespread functions of the c-myc pathway play a crucial role in renal cell carcinoma (RCC) carcinogenesis. Thus, we evaluated the connection between proto-oncogenic c-myc and anti-neoplastic hsa-let-7a (let-7a) in RCC cell lines. The levels of c-myc and let-7a in 3 RCC cell lines (769P, Caki-1 and 786O) were measured after transfecting the cells with let-7a mimics or a negative control. The change in c-myc protein level was confirmed by Western blot. The anti-neoplastic function of let-7a was evaluated using cell counting kit-8 (CCK-8) for proliferation analysis and cell flow cytometry for cell cycle analysis. The changes of downstream targets of c-myc were measured using reverse transcription quantitative real-time PCR (qRT-PCR). Our results suggest for the first time that let-7a acts as a tumor suppressor in RCC cell lines by down-regulating c-myc and c-myc target genes such as proliferating cell nuclear antigen (PCNA), cyclin D1 (CCND1) and the miR17-92 cluster, which is accompanied by proliferation inhibition and cell cycle arrest.

  16. Expression analysis of MYC genes from Tamarix hispida in response to different abiotic stresses.

    Science.gov (United States)

    Ji, Xiaoyu; Wang, Yucheng; Liu, Guifeng

    2012-01-01

    The MYC genes are a group of transcription factors containing both bHLH and ZIP motifs that play important roles in the regulation of abscisic acid (ABA)-responsive genes. In the present study, to investigate the roles of MYC genes under NaCl, osmotic and ABA stress conditions, nine MYC genes were cloned from Tamarix hispida. Real-time reverse-transcriptase (RT)-PCR showed that all nine MYC genes were expressed in root, stem and leaf tissues, but that the levels of the transcripts of these genes in the various tissues differed notably. The MYC genes were highly induced in the roots in response to ABA, NaCl and osmotic stresses after 3 h; however, in the stem and leaf tissues, MYC genes were highly induced only when exposed to these stresses for 6 h. In addition, most of these MYC genes were highly expressed in roots in comparison with stems and leaves. Furthermore, the MYC genes were more highly induced in roots than in stem and leaf tissues, indicating that these genes may play roles in stress responses mainly in the roots rather than the stems and leaves. The results of this present study suggest that MYCs are involved in salt and osmotic stress tolerances and are controlled by the ABA signal transduction pathway.

  17. The adaptive immune system promotes initiation of prostate carcinogenesis in a human c-Myc transgenic mouse model.

    Science.gov (United States)

    Melis, Monique H M; Nevedomskaya, Ekaterina; van Burgsteden, Johan; Cioni, Bianca; van Zeeburg, Hester J T; Song, Ji-Ying; Zevenhoven, John; Hawinkels, Lukas J A C; de Visser, Karin E; Bergman, Andries M

    2017-11-07

    Increasing evidence from epidemiological and pathological studies suggests a role of the immune system in the initiation and progression of multiple cancers, including prostate cancer. Reports on the contribution of the adaptive immune system are contradictive, since both suppression and acceleration of disease development have been reported. This study addresses the functional role of lymphocytes in prostate cancer development using a genetically engineered mouse model (GEMM) of human c-Myc driven prostate cancer (Hi-Myc mice) combined with B and T cell deficiency (RAG1 -/- mice). From a pre-cancerous stage on, Hi-Myc mice showed higher accumulation of immune cells in their prostates then wild-type mice, of which macrophages were the most abundant. The onset of invasive adenocarcinoma was delayed in Hi-MycRAG1 -/- compared to Hi-Myc mice and associated with decreased infiltration of leukocytes into the prostate. In addition, lower levels of the cytokines CXCL2, CCL5 and TGF-β1 were detected in Hi-MycRAG1 -/- compared to Hi-Myc mouse prostates. These results from a GEMM of prostate cancer provide new insights into the promoting role of the adaptive immune system in prostate cancer development. Our findings indicate that the endogenous adaptive immune system does not protect against de novo prostate carcinogenesis in Hi-Myc transgenic mice, but rather accelerates the formation of invasive adenocarcinomas. This may have implications for the development of novel treatment strategies.

  18. Endogenous c-Myc is essential for p53-induced apoptosis in response to DNA damage in vivo.

    Science.gov (United States)

    Phesse, T J; Myant, K B; Cole, A M; Ridgway, R A; Pearson, H; Muncan, V; van den Brink, G R; Vousden, K H; Sears, R; Vassilev, L T; Clarke, A R; Sansom, O J

    2014-06-01

    Recent studies have suggested that C-MYC may be an excellent therapeutic cancer target and a number of new agents targeting C-MYC are in preclinical development. Given most therapeutic regimes would combine C-MYC inhibition with genotoxic damage, it is important to assess the importance of C-MYC function for DNA damage signalling in vivo. In this study, we have conditionally deleted the c-Myc gene in the adult murine intestine and investigated the apoptotic response of intestinal enterocytes to DNA damage. Remarkably, c-Myc deletion completely abrogated the immediate wave of apoptosis following both ionizing irradiation and cisplatin treatment, recapitulating the phenotype of p53 deficiency in the intestine. Consistent with this, c-Myc-deficient intestinal enterocytes did not upregulate p53. Mechanistically, this was linked to an upregulation of the E3 Ubiquitin ligase Mdm2, which targets p53 for degradation in c-Myc-deficient intestinal enterocytes. Further, low level overexpression of c-Myc, which does not impact on basal levels of apoptosis, elicited sustained apoptosis in response to DNA damage, suggesting c-Myc activity acts as a crucial cell survival rheostat following DNA damage. We also identify the importance of MYC during DNA damage-induced apoptosis in several other tissues, including the thymus and spleen, using systemic deletion of c-Myc throughout the adult mouse. Together, we have elucidated for the first time in vivo an essential role for endogenous c-Myc in signalling DNA damage-induced apoptosis through the control of the p53 tumour suppressor protein.

  19. DNA repair in the c-myc proto-oncogene locus: Possible involvement in susceptibility or resistance to plasmacytoma induction in BALB/c mice

    International Nuclear Information System (INIS)

    Beecham, E.J.; Mushinski, J.F.; Shacter, E.; Potter, M.; Bohr, V.A.

    1991-01-01

    This report describes an unexpected difference in the efficiency of removal of UV-induced DNA damage in the c-myc locus in splenic B lymphoblasts from two inbred strains of mice. In cells from plasmacytoma-resistant DBA/2N mice, 35% of UV-induced damage in the regulatory and 5' flank of c-myc is removed by 12 h. However, in cells from plasmacytoma-susceptible BALB/cAn mice, damage is not removed from this region. In the protein-encoding region and 3' flank of c-myc as well as in two dihydrofolate reductase gene fragments, UV damage is repaired with similar efficiency in B lymphoblasts from both strains of mice. Furthermore, in the protein-encoding portion and 3' flank of c-myc, damage is selectively removed from only the transcribed strand. No repair is detected in the nontranscribed strand. In contrast, DNA repair in the 5' flank of c-myc is not strand specific; in DNA from DBA/2N cells, UV damage is rapidly removed from both the transcribed and nontranscribed strands. In BALB/cAn cells no repair was detected in either strand in the 5'flank, consistent with the results with double-stranded, nick-translated probes to this region of c-myc. In addition to the repair studies, we have detected post-UV-damage formation: in most of the genes studied, we find that additional T4 endonuclease-sensitive sites are formed in the DNA 2 h after irradiation. Our findings provide new insights into the details of gene-specific and strand-specific DNA repair and suggest that there may be close links between DNA repair and B-cell neoplastic development

  20. Cooverexpression of EpCAM and c-myc genes in malignant breast

    Indian Academy of Sciences (India)

    oncogene, affects progression, treatment, and diagnosis of many adenocarcinomas. C-myc has been shown to be a downstream target of EpCAM and is also one of the most important proto-oncogenes routinely overexpressed in breast cancer.

  1. Expression Analysis of MYC Genes from Tamarix hispida in Response to Different Abiotic Stresses

    Directory of Open Access Journals (Sweden)

    Guifeng Liu

    2012-01-01

    Full Text Available The MYC genes are a group of transcription factors containing both bHLH and ZIP motifs that play important roles in the regulation of abscisic acid (ABA-responsive genes. In the present study, to investigate the roles of MYC genes under NaCl, osmotic and ABA stress conditions, nine MYC genes were cloned from Tamarix hispida. Real-time reverse-transcriptase (RT-PCR showed that all nine MYC genes were expressed in root, stem and leaf tissues, but that the levels of the transcripts of these genes in the various tissues differed notably. The MYC genes were highly induced in the roots in response to ABA, NaCl and osmotic stresses after 3 h; however, in the stem and leaf tissues, MYC genes were highly induced only when exposed to these stresses for 6 h. In addition, most of these MYC genes were highly expressed in roots in comparison with stems and leaves. Furthermore, the MYC genes were more highly induced in roots than in stem and leaf tissues, indicating that these genes may play roles in stress responses mainly in the roots rather than the stems and leaves. The results of this present study suggest that MYCs are involved in salt and osmotic stress tolerances and are controlled by the ABA signal transduction pathway.

  2. N-Myc regulates expression of pluripotency genes in neuroblastoma including lif, klf2, klf4, and lin28b.

    Directory of Open Access Journals (Sweden)

    Rebecca Cotterman

    2009-06-01

    Full Text Available myc genes are best known for causing tumors when overexpressed, but recent studies suggest endogenous myc regulates pluripotency and self-renewal of stem cells. For example, N-myc is associated with a number of tumors including neuroblastoma, but also plays a central role in the function of normal neural stem and precursor cells (NSC. Both c- and N-myc also enhance the production of induced pluripotent stem cells (iPSC and are linked to neural tumor stem cells. The mechanisms by which myc regulates normal and neoplastic stem-related functions remain largely open questions. Here from a global, unbiased search for N-Myc bound genes using ChIP-chip assays in neuroblastoma, we found lif as a putative N-Myc bound gene with a number of strong N-Myc binding peaks in the promoter region enriched for E-boxes. Amongst putative N-Myc target genes in expression microarray studies in neuroblastoma we also found lif and three additional important embryonic stem cell (ESC-related factors that are linked to production of iPSC: klf2, klf4, and lin28b. To examine the regulation of these genes by N-Myc, we measured their expression using neuroblastoma cells that contain a Tet-regulatable N-myc transgene (TET21N as well as NSC with a nestin-cre driven N-myc knockout. N-myc levels closely correlated with the expression of all of these genes in neuroblastoma and all but lif in NSC. Direct ChIP assays also indicate that N-Myc directly binds the lif promoter. N-Myc regulates trimethylation of lysine 4 of histone H3 in the promoter of lif and possibly in the promoters of several other stem-related genes. Together these findings indicate that N-Myc regulates overlapping stem-related gene expression programs in neuroblastoma and NSC, supporting a novel model by which amplification of the N-myc gene may drive formation of neuroblastoma. They also suggest mechanisms by which Myc proteins more generally contribute to maintenance of pluripotency and self-renewal of ESC as

  3. Long‐distance interaction of the integrated HPV fragment with MYC gene and 8q24.22 region upregulating the allele‐specific MYC expression in HeLa cells

    Science.gov (United States)

    Shen, Congle; Liu, Yongzhen; Shi, Shu; Zhang, Ruiyang; Zhang, Ting; Xu, Qiang; Zhu, Pengfei; Lu, Fengmin

    2017-01-01

    Human papillomavirus (HPV) infection is the most important risk factor for cervical cancer development. In HeLa cell line, the HPV viral genome is integrated at 8q24 in one allele of chromosome 8. It has been reported that the HPV fragment integrated in HeLa genome can cis‐activate the expression of proto‐oncogene MYC, which is located at 500 kb downstream of the integrated site. However, the underlying molecular mechanism of this regulation is unknown. A recent study reported that MYC was highly expressed exclusively from the HPV‐integrated haplotype, and a long‐range chromatin interaction between the integrated HPV fragment and MYC gene has been hypothesized. In this study, we provided the experimental evidences supporting this long‐range chromatin interaction in HeLa cells by using Chromosome Conformation Capture (3C) method. We found that the integrated HPV fragment, MYC and 8q24.22 was close to each other and might form a trimer in spatial location. When knocking out the integrated HPV fragment or 8q24.22 region from chromosome 8 by CRISPR/Cas9 system, the expression of MYC reduced dramatically in HeLa cells. Interestingly, decreased expression was only observed in three from eight cell clones, when only one 8q24.22 allele was knocked out. Functionally, HPV knockout caused senescence‐associated acidic β‐gal activity in HeLa cells. These data indicate a long‐distance interaction of the integrated HPV fragment with MYC gene and 8q24.22 region, providing an alternative mechanism relevant to the carcinogenicity of HPV integration. PMID:28470669

  4. High levels of stable p53 protein and the expression of c-myc in cultured human epithelial tissue after cobalt-60 irradiation

    International Nuclear Information System (INIS)

    Mothersill, C.; Seymour, C.B.; Harney, J.; Hennessy, T.P.

    1994-01-01

    When explants of human uroepithelium or esophageal epithelium are exposed to acute doses of radiation (cobalt-60), the cells which grow out to form the primary cultures show a number of abnormal features. These include the development of characteristic nonsenescent foci. These foci have previously been shown to be c-myc positive and to have an abnormal, tumor-like ultrastructure. Expression of c-myc and the level of stable p53 proteins have now been examined in these cultures 2 weeks after irradiation. Both proteins occurred in dividing cells at the growing edge of the explant and in the foci. The expression of c-myc appeared to be correlated with growth. As expected, variation between individual cultures of normal human cells was noted in the expression of stable p53 protein. Most control uroepithelial cell cultures were negative, but a small cohort showed a wide range of values. The control cultures from the esophageal tissues had high expression of p53, and this decreased marginally after irradiation. Cells positive for p53 were always in cycle and were usually positive for c-myc as well. It would appear from these results that the expression of c-myc and the stable form of the p53 protein occur in irradiated primary cultures of normal human cells both in foci which also express a number of abnormalities and in open-quotes edgeclose quotes cells which are dividing. Cultures of unirradiated cells from esophagus and a small number of uroepithelial samples had high levels of p53. Possible reasons for this are discussed. 33 refs., 2 figs., 3 tabs

  5. Astroglial c-Myc overexpression predisposes mice to primary malignant gliomas

    DEFF Research Database (Denmark)

    Jensen, Niels Aagaard; Pedersen, Karen-Marie; Lihme, Frederikke

    2003-01-01

    Malignant astrocytomas are common human primary brain tumors that result from neoplastic transformation of astroglia or their progenitors. Here we show that deregulation of the c-Myc pathway in developing astroglia predisposes mice to malignant astrocytomas within 2-3 weeks of age. The genetically...... engineered murine (GEM) gliomas harbor a molecular signature resembling that of human primary glioblastoma multiforme, including up-regulation of epidermal growth factor receptor and Mdm2. The GEM gliomas seem to originate in an abnormal population of glial fibrillary acidic protein-expressing cells...... the neoplastic process, presumably by inducing the sustained growth of early astroglial cells. This is in contrast to most other transgenic studies in which c-Myc overexpression requires co-operating transgenes for rapid tumor induction....

  6. Nm23-M2/NDP kinase B induces endogenous c-myc and nm23-M1/NDP kinase A overexpression in BAF3 cells. Both NDP kinases protect the cells from oxidative stress-induced death

    International Nuclear Information System (INIS)

    Arnaud-Dabernat, Sandrine; Masse, Karine; Smani, Moneim; Peuchant, Evelyne; Landry, Marc; Bourbon, Pierre-Marie; Le Floch, Renaud; Daniel, Jean-Yves; Larou, Monique

    2004-01-01

    The nm23 gene family encodes nucleoside diphosphate kinases (NDPKs) which supply the cell with (d)NTPs. The human NDPKB, also known as the PuF protein, binds the c-myc promoter and transactivates the c-myc protooncogene. We have now studied the effects of mouse NDPKA and NDPKB overexpression on endogenous c-myc transactivation in the mouse BAF3 and the rat PC12 cell lines. c-myc transcripts were found to be up-regulated by NDPKB only in the BAF3 line. This suggests that c-myc transcriptional control via NDPKB depends on the presence of cell-specific co-factors. Unexpectedly, NDPKB also induced NDPKA expression. This new effect was found in both cell lines, suggesting that NDPKB-dependent nm23-M1 gene transactivation requires cis and/or trans elements different from those involved in c-myc transactivation. Moreover, the BAF3 cell proliferation capacities were found to be independent of NDPKA or B cell contents. Interestingly, cell death induced by c-myc overexpression or H 2 O 2 exposure was decreased in nm23-transfected compared to control BAF3 cells. These data collectively suggest that NDPKs might improve cell survival by a mechanism coupling DNA repair and transcriptional regulation of genes involved in DNA damage response

  7. Suppression of c-Myc is involved in multi-walled carbon nanotubes' down-regulation of ATP-binding cassette transporters in human colon adenocarcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhaojing [Department of Pharmacology, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, 430030 Wuhan (China); Xu, Yonghong [Institute of Ophthalmological Research, Department of Ophthalmology, Renmin Hospital of Wuhan University, 430060 Wuhan (China); Meng, Xiangning [School of Materials and Metallurgy, Northeastern University, Shenyang 110819 (China); Watari, Fumio [Department of Biomedical, Dental Materials and Engineering, Graduate School of Dental Medicine, Hokkaido University, Sapporo 060-8586 (Japan); Liu, Hudan, E-mail: hudanliu@hust.edu.cn [Department of Pharmacology, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, 430030 Wuhan (China); Chen, Xiao, E-mail: mornsmile@yahoo.com [Department of Pharmacology, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, 430030 Wuhan (China)

    2015-01-01

    Over-expression of ATP-binding cassette (ABC) transporters, a large family of integral membrane proteins that decrease cellular drug uptake and accumulation by active extrusion, is one of the major causes of cancer multi-drug resistance (MDR) that frequently leads to failure of chemotherapy. Carbon nanotubes (CNTs)-based drug delivery devices hold great promise in enhancing the efficacy of cancer chemotherapy. However, CNTs' effects on the ABC transporters remain under-investigated. In this study, we found that multiwalled carbon nanotubes (MWCNTs) reduced transport activity and expression of ABC transporters including ABCB1/Pgp and ABCC4/MRP4 in human colon adenocarcinoma Caco-2 cells. Proto-oncogene c-Myc, which directly regulates ABC gene expression, was concurrently decreased in MWCNT-treated cells and forced over-expression of c-Myc reversed MWCNTs' inhibitory effects on ABCB1 and ABCC4 expression. MWCNT-cell membrane interaction and cell membrane oxidative damage were observed. However, antioxidants such as vitamin C, β-mecaptoethanol and dimethylthiourea failed to antagonize MWCNTs' down-regulation of ABC transporters. These data suggest that MWCNTs may act on c-Myc, but not through oxidative stress, to down-regulate ABC transporter expression. Our findings thus shed light on CNTs' novel cellular effects that may be utilized to develop CNTs-based drug delivery devices to overcome ABC transporter-mediated cancer chemoresistance.

  8. Long-distance interaction of the integrated HPV fragment with MYC gene and 8q24.22 region upregulating the allele-specific MYC expression in HeLa cells.

    Science.gov (United States)

    Shen, Congle; Liu, Yongzhen; Shi, Shu; Zhang, Ruiyang; Zhang, Ting; Xu, Qiang; Zhu, Pengfei; Chen, Xiangmei; Lu, Fengmin

    2017-08-01

    Human papillomavirus (HPV) infection is the most important risk factor for cervical cancer development. In HeLa cell line, the HPV viral genome is integrated at 8q24 in one allele of chromosome 8. It has been reported that the HPV fragment integrated in HeLa genome can cis-activate the expression of proto-oncogene MYC, which is located at 500 kb downstream of the integrated site. However, the underlying molecular mechanism of this regulation is unknown. A recent study reported that MYC was highly expressed exclusively from the HPV-integrated haplotype, and a long-range chromatin interaction between the integrated HPV fragment and MYC gene has been hypothesized. In this study, we provided the experimental evidences supporting this long-range chromatin interaction in HeLa cells by using Chromosome Conformation Capture (3C) method. We found that the integrated HPV fragment, MYC and 8q24.22 was close to each other and might form a trimer in spatial location. When knocking out the integrated HPV fragment or 8q24.22 region from chromosome 8 by CRISPR/Cas9 system, the expression of MYC reduced dramatically in HeLa cells. Interestingly, decreased expression was only observed in three from eight cell clones, when only one 8q24.22 allele was knocked out. Functionally, HPV knockout caused senescence-associated acidic β-gal activity in HeLa cells. These data indicate a long-distance interaction of the integrated HPV fragment with MYC gene and 8q24.22 region, providing an alternative mechanism relevant to the carcinogenicity of HPV integration. © 2017 The Authors International Journal of Cancer published by John Wiley & Sons Ltd on behalf of UICC.

  9. ThMYC4E, candidate Blue aleurone 1 gene controlling the associated trait in Triticum aestivum.

    Directory of Open Access Journals (Sweden)

    Na Li

    Full Text Available Blue aleurone is a useful and interesting trait in common wheat that was derived from related species. Here, transcriptomes of blue and white aleurone were compared for isolating Blue aleurone 1 (Ba1 transferred from Thinopyrum ponticum. In the genes involved in anthocyanin biosynthesis, only a basic helix-loop-helix (bHLH transcription factor, ThMYC4E, had a higher transcript level in blue aleurone phenotype, and was homologous to the genes on chromosome 4 of Triticum aestivum. ThMYC4E carried the characteristic domains (bHLH-MYC_N, HLH and ACT-like of a bHLH transcription factor, and clustered with genes regulating anthocyanin biosynthesis upon phylogenetic analysis. The over-expression of ThMYC4E regulated anthocyanin biosynthesis with the coexpression of the MYB transcription factor ZmC1 from maize. ThMYC4E existed in the genomes of the addition, substitution and near isogenic lines with the blue aleurone trait derived from Th. ponticum, and could not be detected in any germplasm of T. urartu, T. monococcum, T. turgidum, Aegilops tauschii or T. aestivum, with white aleurone. These results suggested that ThMYC4E was candidate Ba1 gene controlling the blue aleurone trait in T. aestivum genotypes carrying Th. ponticum introgression. The ThMYC4E isolation aids in better understanding the genetic mechanisms of the blue aleurone trait and in its more effective use during wheat breeding.

  10. Myc suppression of Nfkb2 accelerates lymphomagenesis

    International Nuclear Information System (INIS)

    Keller, Ulrich; Huber, Jürgen; Nilsson, Jonas A; Fallahi, Mohammad; Hall, Mark A; Peschel, Christian; Cleveland, John L

    2010-01-01

    Deregulated c-Myc expression is a hallmark of several human cancers where it promotes proliferation and an aggressive tumour phenotype. Myc overexpression is associated with reduced activity of Rel/NF-κB, transcription factors that control the immune response, cell survival, and transformation, and that are frequently altered in cancer. The Rel/NF-κB family member NFKB2 is altered by chromosomal translocations or deletions in lymphoid malignancies and deletion of the C-terminal ankyrin domain of NF-κB2 augments lymphocyte proliferation. Precancerous Eμ-Myc-transgenic B cells, Eμ-Myc lymphomas and human Burkitt lymphoma samples were assessed for Nfkb2 expression. The contribution of Nfkb2 to Myc-driven apoptosis, proliferation, and lymphomagenesis was tested genetically in vivo. Here we report that the Myc oncoprotein suppresses Nfkb2 expression in vitro in primary mouse fibroblasts and B cells, and in vivo in the Eμ-Myc transgenic mouse model of human Burkitt lymphoma (BL). NFKB2 suppression by Myc was also confirmed in primary human BL. Promoter-reporter assays indicate that Myc-mediated suppression of Nfkb2 occurs at the level of transcription. The contribution of Nfkb2 to Myc-driven lymphomagenesis was tested in vivo, where Nfkb2 loss was shown to accelerate lymphoma development in Eμ-Myc transgenic mice, by impairing Myc's apoptotic response. Nfkb2 is suppressed by c-Myc and harnesses Myc-driven lymphomagenesis. These data thus link Myc-driven lymphomagenesis to the non-canonical NF-κB pathway

  11. Somatostatin reduces 3H-thymidine incorporation and c-myc, but not thyroglobulin ribonucleic acid levels in human thyroid follicular cells in vitro

    International Nuclear Information System (INIS)

    degli Uberti, E.C.; Hanau, S.; Rossi, R.; Piva, R.; Margutti, A.; Trasforini, G.; Pansini, G.; del Senno, L.

    1991-01-01

    The action of somatostatin (SRIH) on 3 H-thymidine (thy) incorporation and on c-myc and thyroglobulin RNA levels in a suspension of follicles from normal and goitrous human thyroid was examined. SRIH, at 10 - 7 M concentration, inhibited basal thy incorporation (maximally by 4 h lasting for up 24 h), which effect was greater in goiter than in normal thyroid and was also detected in growing adherent epithelial cells. Moreover, in a follicle suspension SRIH prevented TSH-stimulated thy incorporation, both in normal and in goitrous thyroid. Basal expression of c-myc RNA was not affected by SRIH in either tissue, whereas the TSH-stimulated c-myc RNA level was significantly reduced in goiter. No effect of SRIH was observed on basal or TSH-stimulated thyroglobulin RNA levels. SRIH did not alter basal cAMP concentrations in normal or goitrous follicles, but it significantly reduced TSH-stimulated cAMP accumulation both in normal thyroid and in goiter. Overall, our data indicate a direct inhibitory action of SRIH on growth, but not on differentiation, of human thyroid, probably by a mechanism not entirely cAMP dependent

  12. 8q24 allelic imbalance and MYC gene copy number in primary prostate cancer.

    Science.gov (United States)

    Chen, H; Liu, W; Roberts, W; Hooker, S; Fedor, H; DeMarzo, A; Isaacs, W; Kittles, R A

    2010-09-01

    Four independent regions within 8q24 near the MYC gene are associated with risk for prostate cancer (Pca). Here, we investigated allelic imbalance (AI) at 8q24 risk variants and MYC gene DNA copy number (CN) in 27 primary Pcas. Heterozygotes were observed in 24 of 27 patients at one or more 8q24 markers and 27% of the loci exhibited AI in tumor DNA. The 8q24 risk alleles were preferentially favored in the tumors. Increased MYC gene CN was observed in 33% of tumors, and the co-existence of increased MYC gene CN with AI at risk loci was observed in 86% (P<0.004 exact binomial test) of the informative tumors. No AI was observed in tumors, which did not reveal increased MYC gene CN. Higher Gleason score was associated with tumors exhibiting AI (P=0.04) and also with increased MYC gene CN (P=0.02). Our results suggest that AI at 8q24 and increased MYC gene CN may both be related to high Gleason score in Pca. Our findings also suggest that these two somatic alterations may be due to the same preferential chromosomal duplication event during prostate tumorigenesis.

  13. A novel form of the RelA nuclear factor kappaB subunit is induced by and forms a complex with the proto-oncogene c-Myc.

    Science.gov (United States)

    Chapman, Neil R; Webster, Gill A; Gillespie, Peter J; Wilson, Brian J; Crouch, Dorothy H; Perkins, Neil D

    2002-01-01

    Members of both Myc and nuclear factor kappaB (NF-kappaB) families of transcription factors are found overexpressed or inappropriately activated in many forms of human cancer. Furthermore, NF-kappaB can induce c-Myc gene expression, suggesting that the activities of these factors are functionally linked. We have discovered that both c-Myc and v-Myc can induce a previously undescribed, truncated form of the RelA(p65) NF-kappaB subunit, RelA(p37). RelA(p37) encodes the N-terminal DNA binding and dimerization domain of RelA(p65) and would be expected to function as a trans-dominant negative inhibitor of NF-kappaB. Surprisingly, we found that RelA(p37) no longer binds to kappaB elements. This result is explained, however, by the observation that RelA(p37), but not RelA(p65), forms a high-molecular-mass complex with c-Myc. These results demonstrate a previously unknown functional and physical interaction between RelA and c-Myc with many significant implications for our understanding of the role that both proteins play in the molecular events underlying tumourigenesis. PMID:12027803

  14. Effect of c-myc on the ultrastructural structure of cochleae in guinea pigs with noise induced hearing loss

    Energy Technology Data Exchange (ETDEWEB)

    Han, Yu; Zhong, Cuiping [Department of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi' an, 710032 Shaanxi Province (China); Hong, Liu [First Division of Digestive Diseases, Xijing Hospital, Fourth Military Medical University, Xi' an, 710032 Shaanxi Province (China); Wang, Ye; Qiao, Li [Department of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi' an, 710032 Shaanxi Province (China); Qiu, Jianhua, E-mail: qiujh@fmmu.edu.cn [Department of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi' an, 710032 Shaanxi Province (China)

    2009-12-18

    Noise over-stimulation may induce hair cells loss and hearing deficit. The c-myc oncogene is a major regulator for cell proliferation, growth, and apoptosis. However, the role of this gene in the mammalian cochlea is still unclear. The study was designed to firstly investigate its function under noise condition, from the aspect of cochlear ultrastructural changes. We had established the adenoviral vector of c-myc gene and delivered the adenovirus suspension into the scala tympani of guinea pigs 4 days before noise exposure. The empty adenoviral vectors were injected as control. Then, all subjects were exposed to 4-kHz octave-band noise at 110 dB SPL for 8 h/day, 3 days consecutively. Auditory thresholds were assessed by auditory brainstem response, prior to and 7 days following noise exposure. On the seventh days after noise exposure, the cochlear sensory epithelia surface was observed microscopically and the cochleae were taken to study the ultrastructural changes. The results indicated that auditory threshold shift after noise exposure was higher in the ears treated with Ad.EGFP than that treated with Ad.c-myc-EGFP. Stereocilia loss and the disarrangement of outer hair cells were observed, with greater changes found in the Ad.EGFP group. Also, the ultrastructure changes were severe in the Ad.EGFP group, but not obvious in the Ad.c-myc-EGFP group. Therefore, c-myc gene might play an unexpected role in hearing functional and morphological protection from acoustic trauma.

  15. Effect of c-myc on the ultrastructural structure of cochleae in guinea pigs with noise induced hearing loss

    International Nuclear Information System (INIS)

    Han, Yu; Zhong, Cuiping; Hong, Liu; Wang, Ye; Qiao, Li; Qiu, Jianhua

    2009-01-01

    Noise over-stimulation may induce hair cells loss and hearing deficit. The c-myc oncogene is a major regulator for cell proliferation, growth, and apoptosis. However, the role of this gene in the mammalian cochlea is still unclear. The study was designed to firstly investigate its function under noise condition, from the aspect of cochlear ultrastructural changes. We had established the adenoviral vector of c-myc gene and delivered the adenovirus suspension into the scala tympani of guinea pigs 4 days before noise exposure. The empty adenoviral vectors were injected as control. Then, all subjects were exposed to 4-kHz octave-band noise at 110 dB SPL for 8 h/day, 3 days consecutively. Auditory thresholds were assessed by auditory brainstem response, prior to and 7 days following noise exposure. On the seventh days after noise exposure, the cochlear sensory epithelia surface was observed microscopically and the cochleae were taken to study the ultrastructural changes. The results indicated that auditory threshold shift after noise exposure was higher in the ears treated with Ad.EGFP than that treated with Ad.c-myc-EGFP. Stereocilia loss and the disarrangement of outer hair cells were observed, with greater changes found in the Ad.EGFP group. Also, the ultrastructure changes were severe in the Ad.EGFP group, but not obvious in the Ad.c-myc-EGFP group. Therefore, c-myc gene might play an unexpected role in hearing functional and morphological protection from acoustic trauma.

  16. Cellular MYCro economics: Balancing MYC function with MYC expression.

    Science.gov (United States)

    Levens, David

    2013-11-01

    The expression levels of the MYC oncoprotein have long been recognized to be associated with the outputs of major cellular processes including proliferation, cell growth, apoptosis, differentiation, and metabolism. Therefore, to understand how MYC operates, it is important to define quantitatively the relationship between MYC input and expression output for its targets as well as the higher-order relationships between the expression levels of subnetwork components and the flow of information and materials through those networks. Two different views of MYC are considered, first as a molecular microeconomic manager orchestrating specific positive and negative responses at individual promoters in collaboration with other transcription and chromatin components, and second, as a macroeconomic czar imposing an overarching rule onto all active genes. In either case, c-myc promoter output requires multiple inputs and exploits diverse mechanisms to tune expression to the appropriate levels relative to the thresholds of expression that separate health and disease.

  17. Evaluation of Molecular Inhibitors of the c-Myc Oncoprotein

    National Research Council Canada - National Science Library

    Prochownik, Edward V

    2005-01-01

    .... All of these functions require that C-Myc physically associate with another protein. Max. Example of diseases in which c-Myc deregulation occurs include breast cancer (approx. 30% of cases), colon cancer (>85...

  18. Striking similarity in the gene expression levels of individual Myc module members among ESCs, EpiSCs, and partial iPSCs.

    Directory of Open Access Journals (Sweden)

    Masataka Hirasaki

    Full Text Available Predominant transcriptional subnetworks called Core, Myc, and PRC modules have been shown to participate in preservation of the pluripotency and self-renewality of embryonic stem cells (ESCs. Epiblast stem cells (EpiSCs are another cell type that possesses pluripotency and self-renewality. However, the roles of these modules in EpiSCs have not been systematically examined to date. Here, we compared the average expression levels of Core, Myc, and PRC module genes between ESCs and EpiSCs. EpiSCs showed substantially higher and lower expression levels of PRC and Core module genes, respectively, compared with those in ESCs, while Myc module members showed almost equivalent levels of average gene expression. Subsequent analyses revealed that the similarity in gene expression levels of the Myc module between these two cell types was not just overall, but striking similarities were evident even when comparing the expression of individual genes. We also observed equivalent levels of similarity in the expression of individual Myc module genes between induced pluripotent stem cells (iPSCs and partial iPSCs that are an unwanted byproduct generated during iPSC induction. Moreover, our data demonstrate that partial iPSCs depend on a high level of c-Myc expression for their self-renewal properties.

  19. Encapsulation of c-myc antisense oligodeoxynucleotides in lipid particles improves antitumoral efficacy in vivo in a human melanoma line.

    Science.gov (United States)

    Leonetti, C; Biroccio, A; Benassi, B; Stringaro, A; Stoppacciaro, A; Semple, S C; Zupi, G

    2001-06-01

    Phosphorothioate c-myc antisense oligodeoxynucleotides [S]ODNs (free INX-6295) were encapsulated in a new liposome formulation and the antitumor activity was compared to the unencapsulated antisense in a human melanoma xenograft. The systemic administration of INX-6295 encapsulated in stabilized antisense lipid particles (SALP INX-6295) improved plasma AUC (area under the plasma concentration-time curve) and initial half-life of free INX-6295, resulting in a significant enhancement in tumor accumulation and improvement in tumor distribution of antisense oligodeoxynucleotides. Animals treated with SALP INX-6295 exhibited a prolonged reduction of c-myc expression, reduced tumor growth and increased mice survival. When administered in combination with cisplatin (DDP), SALP INX-6295 produced a complete tumor regression in approximately 30% of treated mice, which persisted for at least 60 days following the first cycle of treatment. Finally, the median survival of mice treated with DDP/SALP INX-6295 increased by 105% compared to 84% for animals treated with the combination DDP/free INX-6295. These data indicate that the biological activity and the therapeutic efficacy of c-myc antisense therapy may be improved when these agents are administered in lipid-based delivery systems.

  20. The quest for targets executing MYC-dependent cell transformation

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    Markus eHartl

    2016-06-01

    Full Text Available MYC represents a transcription factor with oncogenic potential converting multiple cellular signals into a broad transcriptional response, thereby controlling the expression of numerous protein-coding and non-coding RNAs important for cell proliferation, metabolism, differentiation, and apoptosis. Constitutive activation of MYC leads to neoplastic cell transformation, and deregulated MYC alleles are frequently observed in many human cancer cell types. Multiple approaches have been performed to isolate genes differentially expressed in cells containing aberrantly activated MYC proteins leading to the identification of thousands of putative targets. Functional analyses of genes differentially expressed in MYC-transformed cells had revealed that so far more than forty upregulated or downregulated MYC targets are actively involved in cell transformation or tumorigenesis. However, for determination which of the known, or yet unidentified targets are responsible for processing the oncogenic MYC program, further systematic and selective approaches are required. The search for critical targets in MYC-dependent tumor cells is exacerbated by the fact that during tumor development, cancer cells progressively evolve in a multistep process thereby acquiring their characteristic features in an additive manner. Functional expression cloning, combinatorial gene expression and appropriate in vivo tests could represent adequate tools for dissecting the complex scenario of MYC-specified cell transformation. In this context, the central goal is to identify a minimal set of targets that suffices to phenocopy oncogenic MYC. Recently developed genomic editing tools could be employed to confirm the requirement of crucial transformation-associated targets.Knowledge about essential MYC regulated genes is beneficial to expedite the development of specific inhibitors to interfere with growth and viability of human tumor cells in which MYC is aberrantly activated

  1. Enhanced human somatic cell reprogramming efficiency by fusion of the MYC transactivation domain and OCT4

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    Ling Wang

    2017-12-01

    Full Text Available The development of human induced pluripotent stem cells (iPSCs holds great promise for regenerative medicine. However the iPSC induction efficiency is still very low and with lengthy reprogramming process. We utilized the highly potent transactivation domain (TAD of MYC protein to engineer the human OCT4 fusion proteins. Applying the MYC-TAD-OCT4 fusion proteins in mouse iPSC generation leads to shorter reprogramming dynamics, with earlier activation of pluripotent markers in reprogrammed cells than wild type OCT4 (wt-OCT4. Dramatic enhancement of iPSC colony induction efficiency and shortened reprogramming dynamics were observed when these MYC-TAD-OCT4 fusion proteins were used to reprogram primary human cells. The OCT4 fusion proteins induced human iPSCs are pluripotent. We further show that the MYC Box I (MBI is dispensable while both MBII and the linking region between MBI/II are essential for the enhanced reprogramming activity of MYC-TAD-OCT4 fusion protein. Consistent with an enhanced transcription activity, the engineered OCT4 significantly stimulated the expression of genes specifically targeted by OCT4-alone, OCT4/SOX2, and OCT4/SOX2/KLF4 during human iPSC induction, compared with the wt-OCT4. The MYC-TAD-OCT4 fusion proteins we generated will be valuable tools for studying the reprogramming mechanisms and for efficient iPSC generation for humans as well as for other species.

  2. c-Myc Enhances Sonic Hedgehog-Induced Medulloblastoma Formation from Nestin-Expressing Neural Progenitors in Mice

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    Ganesh Rao

    2003-05-01

    Full Text Available Medulloblastomas are malignant brain tumors that arise in the cerebella of children. The presumed cellsof-origin are undifferentiated precursors of granule neurons that occupy the external granule layer (EGL of the developing cerebellum. The overexpression of proteins that normally stimulate proliferation of neural progenitor cells may initiate medulloblastoma formation. Two known mitogens for neural progenitors are the c-Myc oncoprotein and Sonic hedgehog (Shh, a crucial determinant of embryonic pattern formation in the central nervous system. We modeled the ability of c-Myc and Shh to induce medulloblastoma in mice using the RCAS/tv-a system, which allows postnatal gene transfer and expression in a cell type-specific manner. We targeted the expression of Shh and c-Myc to nestin-expressing neural progenitor cells by injecting replication-competent ALV splice acceptor (RCAS vectors into the cerebella of newborn mice. Following injection with RCAS-Shh alone, 3/32 (9% mice developed medulloblastomas and 5/32 showed multifocal hyperproliferation of the EGL, possibly a precursor stage of medulloblastoma. Following injection with RCAS-Shh plus RCAS-Myc, 9/39 (23% mice developed medulloblastomas. We conclude that nestin-expressing neural progenitors, present in the cerebellum at birth, can act as the cells-of-origin for medulloblastoma, and that c-Myc cooperates with Shh to enhance tumorigenicity.

  3. Expression of p27 and c-Myc by immunohistochemistry in breast ductal cancers in African American women.

    Science.gov (United States)

    Khan, Farhan; Ricks-Santi, Luisel J; Zafar, Rabia; Kanaan, Yasmine; Naab, Tammey

    2018-06-01

    Proteins p27 and c-Myc are both key players in the cell cycle. While p27, a tumor suppressor, inhibits progression from G1 to S phase, c-Myc, a proto-oncogene, plays a key role in cell cycle regulation and apoptosis. The objective of our study was to determine the association between expression of c-Myc and the loss of p27 by immunohistochemistry (IHC) in the four major subtypes of breast cancer (BC) (Luminal A, Luminal B, HER2, and Triple Negative) and with other clinicopathological factors in a population of 202 African-American (AA) women. Tissue microarrays (TMAs) were constructed from FFPE tumor blocks from primary ductal breast carcinomas in 202 AA women. Five micrometer sections were stained with a mouse monoclonal antibody against p27 and a rabbit monoclonal antibody against c-Myc. The sections were evaluated for intensity of nuclear reactivity (1-3) and percentage of reactive cells; an H-score was derived from the product of these measurements. Loss of p27 expression and c-Myc overexpression showed statistical significance with ER negative (p c-Myc expression/p27 loss and luminal A/B and Her2 overexpressing subtypes. In our study, a statistically significant association between c-Myc expression and p27 loss and the triple negative breast cancers (TNBC) was found in AA women. A recent study found that constitutive c-Myc expression is associated with inactivation of the axin 1 tumor suppressor gene. p27 inhibits cyclin dependent kinase2/cyclin A/E complex formation. Axin 1 and CDK inhibitors may represent possible therapeutic targets for TNBC. Copyright © 2018 Elsevier Inc. All rights reserved.

  4. Shikonin regulates C-MYC and GLUT1 expression through the MST1-YAP1-TEAD1 axis

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    Vališ, Karel, E-mail: karel.valis@biomed.cas.cz [Laboratory of Structural Biology and Cell Signaling, Institute of Microbiology, v.v.i., The Czech Academy of Sciences, Prague (Czech Republic); Faculty of Science, Charles University, Prague (Czech Republic); Talacko, Pavel; Grobárová, Valéria [Laboratory of Structural Biology and Cell Signaling, Institute of Microbiology, v.v.i., The Czech Academy of Sciences, Prague (Czech Republic); Faculty of Science, Charles University, Prague (Czech Republic); Černý, Jan [Faculty of Science, Charles University, Prague (Czech Republic); Novák, Petr, E-mail: pnovak@biomed.cas.cz [Laboratory of Structural Biology and Cell Signaling, Institute of Microbiology, v.v.i., The Czech Academy of Sciences, Prague (Czech Republic); Faculty of Science, Charles University, Prague (Czech Republic)

    2016-12-10

    The general mechanism underlying the tumor suppressor activity of the Hippo signaling pathway remains unclear. In this study, we explore the molecular mechanisms connecting the Hippo signaling pathway with glucose metabolism. We have found that two key regulators of glycolysis, C-MYC and GLUT1, are targets of the Hippo signaling pathway in human leukemia cells. Our results revealed that activation of MST1 by the natural compound shikonin inhibited the expression of GLUT1 and C-MYC. Furthermore, RNAi experiments confirmed the regulation of GLUT1 and C-MYC expression via the MST1-YAP1-TEAD1 axis. Surprisingly, YAP1 was found to positively regulate C-MYC mRNA levels in complex with TEAD1, while it negatively regulates C-MYC levels in cooperation with MST1. Hence, YAP1 serves as a rheostat for C-MYC, which is regulated by MST1. In addition, depletion of MST1 stimulates lactate production, whereas the specific depletion of TEAD1 has an opposite effect. The inhibition of lactate production and cellular proliferation induced by shikonin also depends on the Hippo pathway activity. Finally, a bioinformatic analysis revealed conserved TEAD-binding motifs in the C-MYC and GLUT1 promoters providing another molecular data supporting our observations. In summary, regulation of glucose metabolism could serve as a new tumor suppressor mechanism orchestrated by the Hippo signaling pathway. - Highlights: • Shikonin inhibits C-MYC and GLUT1 expression in MST1 and YAP1 dependent manner. • YAP1-TEAD1 interaction activates C-MYC and GLUT1 expression. • MST1 in cooperation with YAP1 inhibits C-MYC and GLUT1 expression. • MST1-YAP1-TEAD1 axis regulates lactate production by leukemic cells. • MST1 and YAP1 proteins block proliferation of leukemic cells.

  5. Suppression of c-Myc induces apoptosis via an AMPK/mTOR-dependent pathway by 4-O-methyl-ascochlorin in leukemia cells.

    Science.gov (United States)

    Shin, Jae-Moon; Jeong, Yun-Jeong; Cho, Hyun-Ji; Magae, Junji; Bae, Young-Seuk; Chang, Young-Chae

    2016-05-01

    4-O-Methyl-ascochlorin (MAC) is a methylated derivative of the prenyl-phenol antibiotic ascochlorin, which was isolated from an incomplete fungus, Ascochyta viciae. Although the effects of MAC on apoptosis have been reported, the underlying mechanisms remain unknown. Here, we show that MAC promoted apoptotic cell death and downregulated c-Myc expression in K562 human leukemia cells. The effect of MAC on apoptosis was similar to that of 10058-F4 (a c-Myc inhibitor) or c-Myc siRNA, suggesting that the downregulation of c-Myc expression plays a role in the apoptotic effect of MAC. Further investigation showed that MAC downregulated c-Myc by inhibiting protein synthesis. MAC promoted the phosphorylation of AMP-activated protein kinase (AMPK) and inhibited the phosphorylation of mammalian target of rapamycin (mTOR) and its target proteins, including p70S6 K and 4E-BP-1. Treatment of cells with AICAR (an AMPK activator), rapamycin (an mTOR inhibitor), or mTOR siRNA downregulated c-Myc expression and induced apoptosis to a similar extent to that of MAC. These results suggest that the effect of MAC on apoptosis induction in human leukemia cells is mediated by the suppression of c-Myc protein synthesis via an AMPK/mTOR-dependent mechanism.

  6. Effects of c-myc oncogene modulation on differentiation of human small cell lung carcinoma cell lines

    NARCIS (Netherlands)

    Van Waardenburg, RCAM; Meijer, C; Pinto-Sietsma, SJ; De Vries, EGE; Timens, W; Mulder, NM

    1998-01-01

    Amplification and over-expression of oncogenes of the myc family are related to the prognosis of certain solid tumors such as small cell lung cancer (SCLC). For SCLC, c-myc is the oncogene most consistently found to correlate with the end stage behaviour of the tumour, in particular with survival

  7. The Dysregulation of Polyamine Metabolism in Colorectal Cancer Is Associated with Overexpression of c-Myc and C/EBPβ rather than Enterotoxigenic Bacteroides fragilis Infection

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    Anastasiya V. Snezhkina

    2016-01-01

    Full Text Available Colorectal cancer is one of the most common cancers in the world. It is well known that the chronic inflammation can promote the progression of colorectal cancer (CRC. Recently, a number of studies revealed a potential association between colorectal inflammation, cancer progression, and infection caused by enterotoxigenic Bacteroides fragilis (ETBF. Bacterial enterotoxin activates spermine oxidase (SMO, which produces spermidine and H2O2 as byproducts of polyamine catabolism, which, in turn, enhances inflammation and tissue injury. Using qPCR analysis, we estimated the expression of SMOX gene and ETBF colonization in CRC patients. We found no statistically significant associations between them. Then we selected genes involved in polyamine metabolism, metabolic reprogramming, and inflammation regulation and estimated their expression in CRC. We observed overexpression of SMOX, ODC1, SRM, SMS, MTAP, c-Myc, C/EBPβ (CREBP, and other genes. We found that two mediators of metabolic reprogramming, inflammation, and cell proliferation c-Myc and C/EBPβ may serve as regulators of polyamine metabolism genes (SMOX, AZIN1, MTAP, SRM, ODC1, AMD1, and AGMAT as they are overexpressed in tumors, have binding site according to ENCODE ChIP-Seq data, and demonstrate strong coexpression with their targets. Thus, increased polyamine metabolism in CRC could be driven by c-Myc and C/EBPβ rather than ETBF infection.

  8. Blocking c-myc and stat3 by E. coli expressed and enzyme digested siRNA in mouse melanoma

    International Nuclear Information System (INIS)

    Hong Jie; Zhao Yingchun; Huang Weida

    2006-01-01

    Tumour cells often show alteration in the signal-transduction pathways, leading to proliferation in response to external signals. Oncogene overexpression and constitutive expression is a common phenomenon in the development and progression of many human cancers. Therefore oncogenes provide potential targets for cancer therapy. RNA interference (RNAi), mediated by small interfering RNA (siRNA), silences genes with a high degree of specificity and potentially represents a general approach for molecularly targeted anti-cancer therapy. The data presented in this report evaluated the method of systemically administering combined esiRNAs to multiple targets as compared with the method of using a single kind of esiRNA to a single target. Our experimental data revealed that the mixed treatment of esiC-MYC and esiSTAT3 had a better inhibition effect than the single treatment of esiC-MYC or esiSTAT3 on mouse B16 melanoma

  9. Expression of myc family oncoproteins in small-cell lung-cancer cell lines and xenografts

    DEFF Research Database (Denmark)

    Rygaard, K; Vindeløv, L L; Spang-Thomsen, M

    1993-01-01

    A number of genes have altered activity in small-cell lung cancer (SCLC), but especially genes of the myc family (c-myc, L-myc and N-myc) are expressed at high levels in SCLC. Most studies have explored expression at the mRNA level, whereas studies of myc family oncoprotein expression are sparse....... WE examined the expression of myc proto-oncogenes at the mRNA and protein level in 23 cell lines or xenografts. In the cell lines, the doubling time and the cell-cycle distribution, as determined by flow-cytometric DNA analysis, were examined to establish whether the level of myc......-myc. In general, the level of expression of c-myc and N-myc was similar at the mRNA and the protein level. Expression of c-myc was positively correlated with the proliferative index (sum of S and G2+M phases) of cell lines, but not with the population doubling time. In general, L-myc-expressing cell lines had...

  10. Increased radiation-induced transformation in C3H/10T1/2 cells after transfer of an exogenous c-myc gene

    International Nuclear Information System (INIS)

    Sorrentino, V.; Drozdoff, V.; Zeitz, L.; Fleissner, E.

    1987-01-01

    C3H/10T 1/2 cells were infected with a retroviral vector expressing a mouse c-myc oncogene and a drug-selection marker. The resulting cells, morphologically indistinguishable from C3H/10T l/1, displayed a greatly enhanced sensitivity to neoplastic transformation by ionizing radiation or by a chemical carcinogen. Constitutive expression of myc therefore appears to synergize with an initial carcinogenic event, providing a function analogous to a subsequent event that apparently is required for the neoplastic transformation of these cells. This cell system should prove useful in exploring early stages in radiation-induced transformation

  11. Regulation of c-myc and c-fos mRNA levels by polyomavirus: distinct roles for the capsid protein VP1 and the viral early proteins

    International Nuclear Information System (INIS)

    Zullo, J.; Stiles, C.D.; Garcea, R.L.

    1987-01-01

    The levels of c-myc, c-fos, and JE mRNAs accumulate in a biphasic pattern following infection of quiescent BALB/c 3T3 mouse cells with polyomavirus. Maximal levels of c-myc and c-fos mRNAs were seen within 1 hr and were nearly undetectable at 6 hr after infection. At 12 hr after infection mRNA levels were again maximal and remained elevated thereafter. Empty virions (capsids) and recombinant VP 1 protein, purified from Escherichia coli, induced the early but not the late phase of mRNA accumulation. Virions, capsids, and recombinant VP 1 protein stimulated [ 3 H]thymidine nuclear labeling and c-myc mRNA accumulation in a dose-responsive manner paralleling their affinity for the cell receptor for polyoma. The second phase of mRNA accumulation is regulated by the viral early gene products, as shown by polyomavirus early gene mutants and by a transfected cell line (336a) expressing middle tumor antigen upon glucocorticoid addition. These results suggest that polyomavirus interacts with the cell membrane at the onset of infection to increase the levels of mRNA for the cellular genes associated with cell competence for DNA replication, and subsequently these levels are maintained by the action of the early viral proteins

  12. Driver or passenger effects of augmented c-Myc and Cdc20 in gliomagenesis.

    Science.gov (United States)

    Ji, Ping; Zhou, Xinhui; Liu, Qun; Fuller, Gregory N; Phillips, Lynette M; Zhang, Wei

    2016-04-26

    Cdc20 and c-Myc are commonly overexpressed in a broad spectrum of cancers, including glioblastoma (GBM). Despite this clear association, whether c-Myc and Cdc20 overexpression is a driver or passenger event in gliomagenesis remains unclear. Both c-Myc and Cdc20 induced the proliferation of primary glial progenitor cells. c-Myc also promoted the formation of soft agar anchorage-independent colonies. In the RCAS/Ntv-a glia-specific transgenic mouse model, c-Myc increased the GBM incidence from 19.1% to 47.4% by 12 weeks of age when combined with kRas and Akt3 in Ntv-a INK4a-ARF (also known as CDKN2A)-null mice. In contrast, Cdc20 decreased the GBM incidence from 19.1% to 9.1%. Moreover, cell differentiation was modulated by c-Myc in kRas/Akt3-induced GBM on the basis of Nestin/GFAP expression (glial progenitor cell differentiation), while Cdc20 had no effect on primary glial progenitor cell differentiation. We used glial progenitor cells from Ntv-a newborn mice to evaluate the role of c-Myc and Cdc20 in the proliferation and transformation of GBM in vitro and in vivo. We further determined whether c-Myc and Cdc20 have a driver or passenger role in GBM development using kRas/Akt3 signals in a RCAS/Ntv-a mouse model. These results suggest that the driver or passenger of oncogene signaling is dependent on cellular status. c-Myc is a driver when combined with kRas/Akt3 oncogenic signals in gliomagenesis, whereas Cdc20 overexpression is a passenger. Inhibition of cell differentiation of c-Myc may be a target for anti-glioma therapy.

  13. Sodium arsenite alters cell cycle and MTHFR, MT1/2, and c-Myc protein levels in MCF-7 cells

    International Nuclear Information System (INIS)

    Ruiz-Ramos, Ruben; Lopez-Carrillo, Lizbeth; Albores, Arnulfo; Hernandez-Ramirez, Raul U.; Cebrian, Mariano E.

    2009-01-01

    There is limited available information on the effects of arsenic on enzymes participating in the folate cycle. Therefore, our aim was to evaluate the effects of sodium arsenite on the protein levels of methylenetetrahydrofolate reductase (MTHFR) and dihydrofolate reductase (DHFR) and its further relationship with the expression MT1/2 and c-myc in MCF-7 cells. Arsenite treatment (0-10 μM) for 4 h decreased MTHFR levels in a concentration-dependent fashion without significant effects on DHFR. The effects on MTHFR were observed at arsenite concentrations not significantly affecting cell viability. We also observed an increase in S-phase recruitment at all concentrations probed. Lower concentrations (< 5 μM) induced cell proliferation, showing a high proportion of BrdU-stained cells, indicating a higher DNA synthesis rate. However, higher concentrations (≥ 5 μM) or longer treatment periods induced apoptosis. Arsenite also induced dose-dependent increases in MT1/2 and c-Myc protein levels. The levels of MTHFR were inversely correlated to MT1/2 and c-Myc overexpression and increased S-phase recruitment. Our findings indicate that breast epithelial cells are responsive to arsenite and suggest that exposure may pose a risk for breast cancer. The reductions in MTHFR protein levels contribute to understand the mechanisms underlying the induction of genes influencing growth regulation, such as c-myc and MT1/2. However, further research is needed to ascertain if the effects here reported following short-time and high-dose exposure are relevant for human populations chronically exposed to low arsenic concentrations.

  14. Use of a transfected and amplified Drosophila heat shock promoter construction for inducible production of toxic mouse c-myc proteins in CHO cells

    International Nuclear Information System (INIS)

    Wurm, F.M.; Gwinn, K.A.; Papoulas, O.; Pallavicini, M.; Kingston, R.E.

    1987-01-01

    After transfection and selection with methotrexate, CHO cell lines were established which contained up to 2000 copies of an expression vector for c-myc protein. The vector contained the Drosophila heat shock protein 70 (hsp70) promoter fused with the coding region of the mouse c-myc gene. Incubation of cells for up to 3 hours at 43 0 C resulted in at least a 100-fold induction of recombinant c-myc mRNA. When cells were shifted back to 37 0 C, within 1 to 4 hours, this RNA was translated into protein to yield about 250 μg per 10 9 cells. Cells died a few hours later, suggesting that high concentrations of intracellular c-myc are cytotoxic. 47 refs., 5 figs

  15. Evaluation of the antitumor effects of c-Myc-Max heterodimerization inhibitor 100258-F4 in ovarian cancer cells.

    Science.gov (United States)

    Wang, Jiandong; Ma, Xiaoli; Jones, Hannah M; Chan, Leo Li-Ying; Song, Fang; Zhang, Weiyuan; Bae-Jump, Victoria L; Zhou, Chunxiao

    2014-08-21

    Epithelial ovarian carcinoma is the most lethal gynecological cancer due to its silent onset and recurrence with resistance to chemotherapy. Overexpression of oncogene c-Myc is one of the most frequently encountered events present in ovarian carcinoma. Disrupting the function of c-Myc and its downstream target genes is a promising strategy for cancer therapy. Our objective was to evaluate the potential effects of small-molecule c-Myc inhibitor, 10058-F4, on ovarian carcinoma cells and the underlying mechanisms by which 10058-F4 exerts its actions. Using MTT assay, colony formation, flow cytometry and Annexin V FITC assays, we found that 10058-F4 significantly inhibited cell proliferation of both SKOV3 and Hey ovarian cancer cells in a dose dependent manner through induction of apoptosis and cell cycle G1 arrest. Treatment with 10058-F4 reduced cellular ATP production and ROS levels in SKOV3 and Hey cells. Consistently, primary cultures of ovarian cancer treated with 10058-F4 showed induction of caspase-3 activity and inhibition of cell proliferation in 15 of 18 cases. The response to 10058-F4 was independent the level of c-Myc protein over-expression in primary cultures of ovarian carcinoma. These novel findings suggest that the growth of ovarian cancer cells is dependent upon c-MYC activity and that targeting c-Myc-Max heterodimerization could be a potential therapeutic strategy for ovarian cancer.

  16. The c-Myc target glycoprotein1balpha links cytokinesis failure to oncogenic signal transduction pathways in cultured human cells.

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    Qian Wu

    2010-05-01

    Full Text Available An increase in chromosome number, or polyploidization, is associated with a variety of biological changes including breeding of cereal crops and flowers, terminal differentiation of specialized cells such as megakaryocytes, cellular stress and oncogenic transformation. Yet it remains unclear how cells tolerate the major changes in gene expression, chromatin organization and chromosome segregation that invariably accompany polyploidization. We show here that cancer cells can initiate increases in chromosome number by inhibiting cell division through activation of glycoprotein1b alpha (GpIbalpha, a component of the c-Myc signaling pathway. We are able to recapitulate cytokinesis failure in primary cells by overexpression of GpIbalpha in a p53-deficient background. GpIbalpha was found to localize to the cleavage furrow by microscopy analysis and, when overexpressed, to interfere with assembly of the cellular cortical contraction apparatus and normal division. These results indicate that cytokinesis failure and tetraploidy in cancer cells are directly linked to cellular hyperproliferation via c-Myc induced overexpression of GpIbalpha.

  17. A proteomic study of cMyc improvement of CHO culture

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    Dunn Michael J

    2010-03-01

    Full Text Available Abstract Background The biopharmaceutical industry requires cell lines to have an optimal proliferation rate and a high integral viable cell number resulting in a maximum volumetric recombinant protein product titre. Nutrient feeding has been shown to boost cell number and productivity in fed-batch culture, but cell line engineering is another route one may take to increase these parameters in the bioreactor. The use of CHO-K1 cells with a c-myc plasmid allowing for over-expressing c-Myc (designated cMycCHO gives a higher integral viable cell number. In this study the differential protein expression in cMycCHO is investigated using two-dimensional gel electrophoresis (2-DE followed by image analysis to determine the extent of the effect c-Myc has on the cell and the proteins involved to give the new phenotype. Results Over 100 proteins that were differentially expressed in cMycCHO cells were detected with high statistical confidence, of which 41 were subsequently identified by tandem mass spectrometry (LC-MS/MS. Further analysis revealed proteins involved in a variety of pathways. Some examples of changes in protein expression include: an increase in nucleolin, involved in proliferation and known to aid in stabilising anti-apoptotic protein mRNA levels, the cytoskeleton and mitochondrial morphology (vimentin, protein biosysnthesis (eIF6 and energy metabolism (ATP synthetase, and a decreased regulation of all proteins, indentified, involved in matrix and cell to cell adhesion. Conclusion These results indicate several proteins involved in proliferation and adhesion that could be useful for future approaches to improve proliferation and decrease adhesion of CHO cell lines which are difficult to adapt to suspension culture.

  18. c-MYC expression sensitizes medulloblastoma cells to radio- and chemotherapy and has no impact on response in medulloblastoma patients

    Directory of Open Access Journals (Sweden)

    Stearns Duncan

    2011-02-01

    Full Text Available Abstract Background To study whether and how c-MYC expression determines response to radio- and chemotherapy in childhood medulloblastoma (MB. Methods We used DAOY and UW228 human MB cells engineered to stably express different levels of c-MYC, and tested whether c-MYC expression has an effect on radio- and chemosensitivity using the colorimetric 3-(4,5-dimethylthiazol-2-yl-5-(3-carboxymethoxyphenyl-2-(4-sulfophenyl-2H-tetrazolium inner salt (MTS assay, clonogenic survival, apoptosis assays, cell cycle analysis, and western blot assessment. In an effort to validate our results, we analyzed c-MYC mRNA expression in formalin-fixed paraffin-embedded tumor samples from well-documented patients with postoperative residual tumor and compared c-MYC mRNA expression with response to radio- and chemotherapy as examined by neuroradiological imaging. Results In DAOY - and to a lesser extent in UW228 - cells expressing high levels of c-MYC, the cytotoxicity of cisplatin, and etoposide was significantly higher when compared with DAOY/UW228 cells expressing low levels of c-MYC. Irradiation- and chemotherapy-induced apoptotic cell death was enhanced in DAOY cells expressing high levels of c-MYC. The response of 62 of 66 residual tumors was evaluable and response to postoperative radio- (14 responders (CR, PR vs. 5 non-responders (SD, PD or chemotherapy (23 CR/PR vs. 20 SD/PD was assessed. c-MYC mRNA expression was similar in primary MB samples of responders and non-responders (Mann-Whitney U test, p = 0.50, ratio 0.49, 95% CI 0.008-30.0 and p = 0.67, ratio 1.8, 95% CI 0.14-23.5, respectively. Conclusions c-MYC sensitizes MB cells to some anti-cancer treatments in vitro. As we failed to show evidence for such an effect on postoperative residual tumors when analyzed by imaging, additional investigations in xenografts and larger MB cohorts may help to define the exact function of c-MYC in modulating response to treatment.

  19. c-Myc oncogene expression in selected odontogenic cysts and tumors: An immunohistochemical study

    Science.gov (United States)

    Moosvi, Zama; Rekha, K

    2013-01-01

    Aim: To investigate the role of c-Myc oncogene in selected odontogenic cysts and tumors. Materials and Methods: Ten cases each of ameloblastoma, adenomatoid odontogenic tumor (AOT), odontogenic keratocyst (OKC), dentigerous cyst, and radicular cyst were selected and primary monoclonal mouse anti-human c-Myc antibody was used in a dilution of 1: 50. Statistical Analysis was performed using Mann Whitney U test. Results: 80% positivity was observed in ameloblastoma, AOT and OKC; 50% positivity in radicular cyst and 20% positivity in dentigerous cyst. Comparison of c-Myc expression between ameloblastoma and AOT did not reveal significant results. Similarly, no statistical significance was observed when results of OKC were compared with ameloblastoma and AOT. In contrast, significant differences were seen on comparison of dentigerous cyst with ameloblastoma and AOT and radicular cyst with AOT. Conclusion: From the above data we conclude that (1) Ameloblastoma and AOT have similar proliferative potential and their biologic behavior cannot possibly be attributed to it. (2) OKC has an intrinsic growth potential which is absent in other cysts and reinforces its classification as keratocystic odontogenic tumor. PMID:23798830

  20. Glutathione Depletion Induced by c-Myc Downregulation Triggers Apoptosis on Treatment with Alkylating Agents1

    Science.gov (United States)

    Biroccio, Annamaria; Benassi, Barbara; Fiorentino, Francesco; Zupi, Gabriella

    2004-01-01

    Abstract Here we investigate the mechanism(s) involved in the c-Myc-dependent drug response of melanoma cells. By using three M14-derived c-Myc low-expressing clones, we demonstrate that alkylating agents, cisplatin and melphalan, trigger apoptosis in the c-Myc antisense transfectants, but not in the parental line. On the contrary, topoisomerase inhibitors, adriamycin and camptothecin, induce apoptosis to the same extent regardless of c-Myc expression. Because we previously demonstrated that c-Myc downregulation decreases glutathione (GSH) content, we evaluated the role of GSH in the apoptosis induced by the different drugs. In control cells treated with one of the alkylating agents or the others, GSH depletion achieved by l-buthionine-sulfoximine preincubation opens the apoptotic pathway. The apoptosis proceeded through early Bax relocalization, cytochrome c release, and concomitant caspase-9 activation, whereas reactive oxygen species production and alteration of mitochondria membrane potential were late events. That GSH was determining in the c-Myc-dependent drug-induced apoptosis was demonstrated by altering the intracellular GSH content of the c-Myc low-expressing cells up to the level of controls. Indeed, GSH ethyl ester-mediated increase of GSH abrogated apoptosis induced by cisplatin and melphalan by inhibition of Bax/cytochrome c redistribution. The relationship among c-Myc, GSH content, and the response to alkylating agent has been also evaluated in the M14 Myc overexpressing clones as well as in the melanoma JR8 c-Myc antisense transfectants. All together, these results demonstrate that GSH plays a key role in governing c-Myc-dependent drug-induced apoptosis. PMID:15153331

  1. Analysis of Myc-induced histone modifications on target chromatin.

    Directory of Open Access Journals (Sweden)

    Francesca Martinato

    Full Text Available The c-myc proto-oncogene is induced by mitogens and is a central regulator of cell growth and differentiation. The c-myc product, Myc, is a transcription factor that binds a multitude of genomic sites, estimated to be over 10-15% of all promoter regions. Target promoters generally pre-exist in an active or poised chromatin state that is further modified by Myc, contributing to fine transcriptional regulation (activation or repression of the afferent gene. Among other mechanisms, Myc recruits histone acetyl-transferases to target chromatin and locally promotes hyper-acetylation of multiple lysines on histones H3 and H4, although the identity and combination of the modified lysines is unknown. Whether Myc dynamically regulates other histone modifications (or marks at its binding sites also remains to be addressed. Here, we used quantitative chromatin immunoprecipitation (qChIP to profile a total of 24 lysine-acetylation and -methylation marks modulated by Myc at target promoters in a human B-cell line with a regulatable c-myc transgene. Myc binding promoted acetylation of multiple lysines, primarily of H3K9, H3K14, H3K18, H4K5 and H4K12, but significantly also of H4K8, H4K91 and H2AK5. Dimethylation of H3K79 was also selectively induced at target promoters. A majority of target promoters showed co-induction of multiple marks - in various combinations - correlating with recruitment of the two HATs tested (Tip60 and HBO1, incorporation of the histone variant H2A.Z and transcriptional activation. Based on this and previous findings, we surmise that Myc recruits the Tip60/p400 complex to achieve a coordinated histone acetylation/exchange reaction at activated promoters. Our data are also consistent with the additive and redundant role of multiple acetylation events in transcriptional activation.

  2. Rictor regulates FBXW7-dependent c-Myc and cyclin E degradation in colorectal cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Zheng [Markey Cancer Center, The University of Kentucky, 800 Rose Street, Lexington, KY 40536 (United States); Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, 1838 Guangzhou Dadao Bei, Guangzhou 510515 (China); Zhou, Yuning [Markey Cancer Center, The University of Kentucky, 800 Rose Street, Lexington, KY 40536 (United States); Evers, B. Mark [Markey Cancer Center, The University of Kentucky, 800 Rose Street, Lexington, KY 40536 (United States); Department of Surgery, The University of Kentucky, 800 Rose Street, Lexington, KY 40536 (United States); Wang, Qingding, E-mail: qingding.wang@uky.edu [Markey Cancer Center, The University of Kentucky, 800 Rose Street, Lexington, KY 40536 (United States); Department of Surgery, The University of Kentucky, 800 Rose Street, Lexington, KY 40536 (United States)

    2012-02-10

    Highlights: Black-Right-Pointing-Pointer Rictor associates with FBXW7 to form an E3 complex. Black-Right-Pointing-Pointer Knockdown of rictor decreases ubiquitination of c-Myc and cylin E. Black-Right-Pointing-Pointer Knockdown of rictor increases protein levels of c-Myc and cylin E. Black-Right-Pointing-Pointer Overexpression of rictor induces the degradation of c-Myc and cyclin E proteins. Black-Right-Pointing-Pointer Rictor regulation of c-Myc and cyclin E requires FBXW7. -- Abstract: Rictor (Rapamycin-insensitive companion of mTOR) forms a complex with mTOR and phosphorylates and activates Akt. Activation of Akt induces expression of c-Myc and cyclin E, which are overexpressed in colorectal cancer and play an important role in colorectal cancer cell proliferation. Here, we show that rictor associates with FBXW7 to form an E3 complex participating in the regulation of c-Myc and cyclin E degradation. The Rictor-FBXW7 complex is biochemically distinct from the previously reported mTORC2 and can be immunoprecipitated independently of mTORC2. Moreover, knocking down of rictor in serum-deprived colorectal cancer cells results in the decreased ubiquitination and increased protein levels of c-Myc and cyclin E while overexpression of rictor induces the degradation of c-Myc and cyclin E proteins. Genetic knockout of FBXW7 blunts the effects of rictor, suggesting that rictor regulation of c-Myc and cyclin E requires FBXW7. Our findings identify rictor as an important component of FBXW7 E3 ligase complex participating in the regulation of c-Myc and cyclin E protein ubiquitination and degradation. Importantly, our results suggest that elevated growth factor signaling may contribute to decrease rictor/FBXW7-mediated ubiquitination of c-Myc and cyclin E, thus leading to accumulation of cyclin E and c-Myc in colorectal cancer cells.

  3. Rictor regulates FBXW7-dependent c-Myc and cyclin E degradation in colorectal cancer cells

    International Nuclear Information System (INIS)

    Guo, Zheng; Zhou, Yuning; Evers, B. Mark; Wang, Qingding

    2012-01-01

    Highlights: ► Rictor associates with FBXW7 to form an E3 complex. ► Knockdown of rictor decreases ubiquitination of c-Myc and cylin E. ► Knockdown of rictor increases protein levels of c-Myc and cylin E. ► Overexpression of rictor induces the degradation of c-Myc and cyclin E proteins. ► Rictor regulation of c-Myc and cyclin E requires FBXW7. -- Abstract: Rictor (Rapamycin-insensitive companion of mTOR) forms a complex with mTOR and phosphorylates and activates Akt. Activation of Akt induces expression of c-Myc and cyclin E, which are overexpressed in colorectal cancer and play an important role in colorectal cancer cell proliferation. Here, we show that rictor associates with FBXW7 to form an E3 complex participating in the regulation of c-Myc and cyclin E degradation. The Rictor–FBXW7 complex is biochemically distinct from the previously reported mTORC2 and can be immunoprecipitated independently of mTORC2. Moreover, knocking down of rictor in serum-deprived colorectal cancer cells results in the decreased ubiquitination and increased protein levels of c-Myc and cyclin E while overexpression of rictor induces the degradation of c-Myc and cyclin E proteins. Genetic knockout of FBXW7 blunts the effects of rictor, suggesting that rictor regulation of c-Myc and cyclin E requires FBXW7. Our findings identify rictor as an important component of FBXW7 E3 ligase complex participating in the regulation of c-Myc and cyclin E protein ubiquitination and degradation. Importantly, our results suggest that elevated growth factor signaling may contribute to decrease rictor/FBXW7-mediated ubiquitination of c-Myc and cyclin E, thus leading to accumulation of cyclin E and c-Myc in colorectal cancer cells.

  4. Impact of hydrodynamic injection and phiC31 integrase on tumor latency in a mouse model of MYC-induced hepatocellular carcinoma.

    Directory of Open Access Journals (Sweden)

    Lauren E Woodard

    2010-06-01

    Full Text Available Hydrodynamic injection is an effective method for DNA delivery in mouse liver and is being translated to larger animals for possible clinical use. Similarly, phiC31 integrase has proven effective in mediating long-term gene therapy in mice when delivered by hydrodynamic injection and is being considered for clinical gene therapy applications. However, chromosomal aberrations have been associated with phiC31 integrase expression in tissue culture, leading to questions about safety.To study whether hydrodynamic delivery alone, or in conjunction with delivery of phiC31 integrase for long-term transgene expression, could facilitate tumor formation, we used a transgenic mouse model in which sustained induction of the human C-MYC oncogene in the liver was followed by hydrodynamic injection. Without injection, mice had a median tumor latency of 154 days. With hydrodynamic injection of saline alone, the median tumor latency was significantly reduced, to 105 days. The median tumor latency was similar, 106 days, when a luciferase donor plasmid and backbone plasmid without integrase were administered. In contrast, when active or inactive phiC31 integrase and donor plasmid were supplied to the mouse liver, the median tumor latency was 153 days, similar to mice receiving no injection.Our data suggest that phiC31 integrase does not facilitate tumor formation in this C-MYC transgenic mouse model. However, in groups lacking phiC31 integrase, hydrodynamic injection appeared to contribute to C-MYC-induced hepatocellular carcinoma in adult mice. Although it remains to be seen to what extent these findings may be extrapolated to catheter-mediated hydrodynamic delivery in larger species, they suggest that caution should be used during translation of hydrodynamic injection to clinical applications.

  5. N-Myc Drives Neuroendocrine Prostate Cancer Initiated from Human Prostate Epithelial Cells

    Science.gov (United States)

    Lee, John K.; Phillips, John W.; Smith, Bryan A.; Park, Jung Wook; Stoyanova, Tanya; McCaffrey, Erin F.; Baertsch, Robert; Sokolov, Artem; Meyerowitz, Justin G.; Mathis, Colleen; Cheng, Donghui; Stuart, Joshua M.; Shokat, Kevan M.; Gustafson, W. Clay; Huang, Jiaoti; Witte, Owen N.

    2016-01-01

    SUMMARY MYCN amplification and overexpression are common in neuroendocrine prostate cancer (NEPC). However, the impact of aberrant N-Myc expression in prostate tumorigenesis and the cellular origin of NEPC have not been established. We define N-Myc and activated AKT1 as oncogenic components sufficient to transform human prostate epithelial cells to prostate adenocarcinoma and NEPC with phenotypic and molecular features of aggressive, late-stage human disease. We directly show that prostate adenocarcinoma and NEPC can arise from a common epithelial clone. Further, N-Myc is required for tumor maintenance and destabilization of N-Myc through Aurora A kinase inhibition reduces tumor burden. Our findings establish N-Myc as a driver of NEPC and a target for therapeutic intervention. PMID:27050099

  6. TATA-binding protein and the retinoblastoma gene product bind to overlapping epitopes on c-Myc and adenovirus E1A protein

    NARCIS (Netherlands)

    Hateboer, G.; Timmers, H.T.M.; Rustgi, A.K.; Billaud, Marc; Veer, L.J. Van 't; Bernards, R.A.

    1993-01-01

    Using a protein binding assay, we show that the amino-teminal 204 amino acids of the c-Myc protein interact di y with a key component of the basal p tdon factor TFID, the TATA box-binding protein (TBP). Essentialy the same region of the c-Myc protein alo binds the product of the retinoblatoma

  7. Translocations at 8q24 juxtapose MYC with genes that harbor superenhancers resulting in overexpression and poor prognosis in myeloma patients

    International Nuclear Information System (INIS)

    Walker, B A; Wardell, C P; Brioli, A; Boyle, E; Kaiser, M F; Begum, D B; Dahir, N B; Johnson, D C; Ross, F M; Davies, F E; Morgan, G J

    2014-01-01

    Secondary MYC translocations in myeloma have been shown to be important in the pathogenesis and progression of disease. Here, we have used a DNA capture and massively parallel sequencing approach to identify the partner chromosomes in 104 presentation myeloma samples. 8q24 breakpoints were identified in 21 (20%) samples with partner loci including IGH, IGK and IGL, which juxtapose the immunoglobulin (Ig) enhancers next to MYC in 8/23 samples. The remaining samples had partner loci including XBP1, FAM46C, CCND1 and KRAS, which are important in B-cell maturation or myeloma pathogenesis. Analysis of the region surrounding the breakpoints indicated the presence of superenhancers on the partner chromosomes and gene expression analysis showed increased expression of MYC in these samples. Patients with MYC translocations had a decreased progression-free and overall survival. We postulate that translocation breakpoints near MYC result in colocalization of the gene with superenhancers from loci, which are important in the development of the cell type in which they occur. In the case of myeloma these are the Ig loci and those important for plasma cell development and myeloma pathogenesis, resulting in increased expression of MYC and an aggressive disease phenotype

  8. Celastrol inhibits chondrosarcoma proliferation, migration and invasion through suppression CIP2A/c-MYC signaling pathway

    Directory of Open Access Journals (Sweden)

    Jinhui Wu

    2017-05-01

    Full Text Available Chondrosarcomas (CS is the second most frequent tumors of cartilage origin. A small compound extracted from Thunder God Vine (Tripterygium wilfordii Hook. F. called celastrol can directly bound CIP2A protein and effectively inhibit cell proliferation and induce apoptosis in several cancer cells. However, little knowledge is concern about the important role of CIP2A in CS patients and the therapeutic value of celastrol on CS. Our results showed that CIP2A and c-MYC were verified to be oncoproteins by detecting their mRNA and protein expression in 10 human CS tissues by qRT-PCR and Western blots. After treatment of celastrol, the proliferation, migration and invasion were significantly inhibited; whereas the apoptosis was largely induced in human CS cell lines. In addition, celastrol inhibited the expression of CIP2A, c-MYC, and suppressed apoptotic proteins BAX and caspase-8 in human CS cells, on the other hand, it induced the expression of antiapoptotic protein Bcl-2. Finally, knockdown of CIP2A also inhibited the migration and invasion and induced apoptosis of human CS cells. To sum up, we found that celastrol had effects on inhibiting proliferation, migration, invasion and inducing apoptosis through suppression CIP2A/c-MYC signaling pathway in vitro, which may provide a new therapeutic regimen for CS.

  9. MYC gene delivery to adult mouse utricles stimulates proliferation of postmitotic supporting cells in vitro.

    Science.gov (United States)

    Burns, Joseph C; Yoo, James J; Atala, Anthony; Jackson, John D

    2012-01-01

    The inner ears of adult humans and other mammals possess a limited capacity for regenerating sensory hair cells, which can lead to permanent auditory and vestibular deficits. During development and regeneration, undifferentiated supporting cells within inner ear sensory epithelia can self-renew and give rise to new hair cells; however, these otic progenitors become depleted postnatally. Therefore, reprogramming differentiated supporting cells into otic progenitors is a potential strategy for restoring regenerative potential to the ear. Transient expression of the induced pluripotency transcription factors, Oct3/4, Klf4, Sox2, and c-Myc reprograms fibroblasts into neural progenitors under neural-promoting culture conditions, so as a first step, we explored whether ectopic expression of these factors can reverse supporting cell quiescence in whole organ cultures of adult mouse utricles. Co-infection of utricles with adenoviral vectors separately encoding Oct3/4, Klf4, Sox2, and the degradation-resistant T58A mutant of c-Myc (c-MycT58A) triggered significant levels of supporting cell S-phase entry as assessed by continuous BrdU labeling. Of the four factors, c-MycT58A alone was both necessary and sufficient for the proliferative response. The number of BrdU-labeled cells plateaued between 5-7 days after infection, and then decreased ~60% by 3 weeks, as many cycling cells appeared to enter apoptosis. Switching to differentiation-promoting culture medium at 5 days after ectopic expression of c-MycT58A temporarily attenuated the loss of BrdU-labeled cells and accompanied a very modest but significant expansion of the sensory epithelium. A small number of the proliferating cells in these cultures labeled for the hair cell marker, myosin VIIA, suggesting they had begun differentiating towards a hair cell fate. The results indicate that ectopic expression of c-MycT58A in combination with methods for promoting cell survival and differentiation may restore regenerative

  10. MYC gene delivery to adult mouse utricles stimulates proliferation of postmitotic supporting cells in vitro.

    Directory of Open Access Journals (Sweden)

    Joseph C Burns

    Full Text Available The inner ears of adult humans and other mammals possess a limited capacity for regenerating sensory hair cells, which can lead to permanent auditory and vestibular deficits. During development and regeneration, undifferentiated supporting cells within inner ear sensory epithelia can self-renew and give rise to new hair cells; however, these otic progenitors become depleted postnatally. Therefore, reprogramming differentiated supporting cells into otic progenitors is a potential strategy for restoring regenerative potential to the ear. Transient expression of the induced pluripotency transcription factors, Oct3/4, Klf4, Sox2, and c-Myc reprograms fibroblasts into neural progenitors under neural-promoting culture conditions, so as a first step, we explored whether ectopic expression of these factors can reverse supporting cell quiescence in whole organ cultures of adult mouse utricles. Co-infection of utricles with adenoviral vectors separately encoding Oct3/4, Klf4, Sox2, and the degradation-resistant T58A mutant of c-Myc (c-MycT58A triggered significant levels of supporting cell S-phase entry as assessed by continuous BrdU labeling. Of the four factors, c-MycT58A alone was both necessary and sufficient for the proliferative response. The number of BrdU-labeled cells plateaued between 5-7 days after infection, and then decreased ~60% by 3 weeks, as many cycling cells appeared to enter apoptosis. Switching to differentiation-promoting culture medium at 5 days after ectopic expression of c-MycT58A temporarily attenuated the loss of BrdU-labeled cells and accompanied a very modest but significant expansion of the sensory epithelium. A small number of the proliferating cells in these cultures labeled for the hair cell marker, myosin VIIA, suggesting they had begun differentiating towards a hair cell fate. The results indicate that ectopic expression of c-MycT58A in combination with methods for promoting cell survival and differentiation may restore

  11. E1A-dependent trans-activation of the human MYC promoter is mediated by the E2F factor

    International Nuclear Information System (INIS)

    Hiebert, S.W.; Lipp, M.; Nevins, J.R.

    1989-01-01

    E2F is a cellular transcription factor that binds to two sites in the adenovirus E2 promoter. Previous experiments have implicated E2F in the E1A-dependent transactivation of the E2 gene since levels of active E2F increase markedly during adenovirus infection in parallel with the increase in E2 transcription, and an E2F binding site can confer E1A inducibility to a heterologous promoter. Here the authors show that E2F binds to two sequence elements within the P2 promoter of the human MYC gene which are within a region that is critical for promoter activity. The MYC promoter can be trans-activated in an E1A-dependent manner and site-directed mutagenesis demonstrates that these E2F elements are essential for trans-activation. Finally, they also find that adenovirus infection of quiescent cells results in a stimulation of the endogenous MYC gene. They conclude that the activation of the E2F factor, which is likely responsible for the activation of viral E2 transcription, is also responsible for the E1A-dependent induction of MYC transcription

  12. Evaluation of Myc Gene Amplification in Prostate Cancer Using a Dual Color Chromogenic in-Situ Hybridization (Dual CISH Assay

    Directory of Open Access Journals (Sweden)

    Daniel Lerda

    2013-04-01

    Full Text Available Objetive: The overall purpose of the study was to demonstrate applicability of the Dako dual-color chromogenic in situ hybridization (CISH assay (DAKO Denmark, Glostrup with respect to fluorescence in situ hybridization (FISH probes MYC-C. Methods: MYC gene amplification by FISH and Dako dual-color CISH Results: The study showed that the dual-color CISH assay can convert Texas red and fluorescein isothiocyanate (FITC signals into chromogenic signals. The dual –color CISH assay was performed on 40 cases of prostate cancer. Amplification was identified in 12 of 40 (30% tumors. No amplification was seen in 28 of 40 (70% tumors. FISH data were available in total of 40 tumors. All tumors showed concordant results between dual-color CISH and FISH for classifying a tumor as MYC amplified or not amplified. Conclusions: We conclude that dual-color Dako CISH assay is an accurate method for determining MYC gene amplification with added advantages that make it a more practically useful method. [J Interdiscipl Histopathol 2013; 1(2.000: 81-84

  13. Differential cellular responses by oncogenic levels of c-Myc expression in long-term confluent retinal pigment epithelial cells.

    Science.gov (United States)

    Wang, Yiping; Cheng, Xiangdong; Samma, Muhammad Kaleem; Kung, Sam K P; Lee, Clement M; Chiu, Sung Kay

    2018-06-01

    c-Myc is a highly pleiotropic transcription factor known to control cell cycle progression, apoptosis, and cellular transformation. Normally, ectopic expression of c-Myc is associated with promoting cell proliferation or triggering cell death via activating p53. However, it is not clear how the levels of c-Myc lead to different cellular responses. Here, we generated a series of stable RPE cell clones expressing c-Myc at different levels, and found that consistent low level of c-Myc induced cellular senescence by activating AP4 in post-confluent RPE cells, while the cells underwent cell death at high level of c-Myc. In addition, high level of c-Myc could override the effect of AP4 on cellular senescence. Further knockdown of AP4 abrogated senescence-like phenotype in cells expressing low level of c-Myc, and accelerated cell death in cells with medium level of c-Myc, indicating that AP4 was required for cellular senescence induced by low level of c-Myc.

  14. Inhibition of c-Myc overcomes cytotoxic drug resistance in acute myeloid leukemia cells by promoting differentiation.

    Directory of Open Access Journals (Sweden)

    Xiao-Na Pan

    Full Text Available Nowadays, drug resistance still represents a major obstacle to successful acute myeloid leukemia (AML treatment and the underlying mechanism is not fully elucidated. Here, we found that high expression of c-Myc was one of the cytogenetic characteristics in the drug-resistant leukemic cells. c-Myc over-expression in leukemic cells induced resistance to chemotherapeutic drugs, enhanced colony formation capacity and inhibited cell differentiation induced by all-trans retinoic acid (ATRA. Meanwhile, inhibition of c-Myc by shRNA or specific c-Myc inhibitor 10058-F4 rescued the sensitivity to cytotoxic drugs, restrained the colony formation ability and promoted differentiation. RT-PCR and western blotting analysis showed that down-regulation of C/EBPβ contributed to the poor differentiation state of leukemic cells induced by c-Myc over-expression. Importantly, over-expression of C/EBPβ could reverse c-Myc induced drug resistance. In primary AML cells, the c-Myc expression was negatively correlated with C/EBPβ. 10058-F4, displayed anti-proliferative activity and increased cellular differentiation with up-regulation of C/EBPβ in primary AML cells. Thus, our study indicated that c-Myc could be a novel target to overcome drug resistance, providing a new approach in AML therapy.

  15. MYC through miR-17-92 Suppresses Specific Target Genes to Maintain Survival, Autonomous Proliferation, and a Neoplastic State

    KAUST Repository

    Li, Yulin; Choi, Peter  S.; Casey, Stephanie  C.; Dill, David  L.; Felsher, Dean  W.

    2014-01-01

    The MYC oncogene regulates gene expression through multiple mechanisms, and its overexpression culminates in tumorigenesis. MYC inactivation reverses turmorigenesis through the loss of distinguishing features of cancer, including autonomous proliferation and survival. Here we report that MYC via miR-17-92 maintains a neoplastic state through the suppression of chromatin regulatory genes Sin3b, Hbp1, Suv420h1, and Btg1, as well as the apoptosis regulator Bim. The enforced expression of miR-17-92 prevents MYC suppression from inducing proliferative arrest, senescence, and apoptosis and abrogates sustained tumor regression. Knockdown of the five miR-17-92 target genes blocks senescence and apoptosis while it modestly delays proliferative arrest, thus partially recapitulating miR-17-92 function. We conclude that MYC, via miR-17-92, maintains a neoplastic state by suppressing specific target genes.

  16. MYC through miR-17-92 Suppresses Specific Target Genes to Maintain Survival, Autonomous Proliferation, and a Neoplastic State

    KAUST Repository

    Li, Yulin

    2014-08-01

    The MYC oncogene regulates gene expression through multiple mechanisms, and its overexpression culminates in tumorigenesis. MYC inactivation reverses turmorigenesis through the loss of distinguishing features of cancer, including autonomous proliferation and survival. Here we report that MYC via miR-17-92 maintains a neoplastic state through the suppression of chromatin regulatory genes Sin3b, Hbp1, Suv420h1, and Btg1, as well as the apoptosis regulator Bim. The enforced expression of miR-17-92 prevents MYC suppression from inducing proliferative arrest, senescence, and apoptosis and abrogates sustained tumor regression. Knockdown of the five miR-17-92 target genes blocks senescence and apoptosis while it modestly delays proliferative arrest, thus partially recapitulating miR-17-92 function. We conclude that MYC, via miR-17-92, maintains a neoplastic state by suppressing specific target genes.

  17. Evaluation of Myc Gene Amplification in Prostate Cancer Using a Dual Color Chromogenic in-Situ Hybridization (Dual CISH) Assay

    OpenAIRE

    Daniel Lerda; Marta Cabrera; Jorge Flores; Luis Gutierrez; Armando Chierichetti; Martin Revol; Hernan Garcia Onto

    2013-01-01

    Objetive: The overall purpose of the study was to demonstrate applicability of the Dako dual-color chromogenic in situ hybridization (CISH) assay (DAKO Denmark, Glostrup) with respect to fluorescence in situ hybridization (FISH) probes MYC-C. Methods: MYC gene amplification by FISH and Dako dual-color CISH Results: The study showed that the dual-color CISH assay can convert Texas red and fluorescein isothiocyanate (FITC) signals into chromogenic signals. The dual –color CISH assay was p...

  18. Induction of non-apoptotic programmed cell death by oncogenic RAS in human epithelial cells and its suppression by MYC overexpression.

    Science.gov (United States)

    Dendo, Kasumi; Yugawa, Takashi; Nakahara, Tomomi; Ohno, Shin-Ichi; Goshima, Naoki; Arakawa, Hirofumi; Kiyono, Tohru

    2018-02-09

    Oncogenic mutations of RAS genes, found in about 30% of human cancers, are considered to play important roles in cancer development. However, oncogenic RAS can also induce senescence in mouse and human normal fibroblasts. In some cell lines, oncogenic RAS has been reported to induce non-apoptotic programed cell death (PCD). Here, we investigated effects of oncogenic RAS expression in several types of normal human epithelial cells. Oncogenic RAS but not wild-type RAS stimulated macropinocytosis with accumulation of large-phase lucent vacuoles in the cytoplasm, subsequently leading to cell death which was indistinguishable from a recently proposed new type of PCD, methuosis. A RAC1 inhibitor suppressed accumulation of macropinosomes and overexpression of MYC attenuated oncogenic RAS-induced such accumulation, cell cycle arrest and cell death. MYC suppression or rapamycin treatment in some cancer cell lines harbouring oncogenic mutations in RAS genes induced cell death with accumulation of macropinosomes. These results suggest that this type of non-apoptotic PCD is a tumour-suppressing mechanism acting against oncogenic RAS mutations in normal human epithelial cells, which can be overcome by MYC overexpression, raising the possibility that its induction might be a novel approach to treatment of RAS-mutated human cancers. © The Author(s) 2017. Published by Oxford University Press.

  19. Low expression of c-Myc protein predicts poor outcomes in patients with hepatocellular carcinoma after resection.

    Science.gov (United States)

    Ji, Fei; Zhang, Zhi-Heng; Zhang, Yi; Shen, Shun-Li; Cao, Qing-Hua; Zhang, Long-Juan; Li, Shao-Qiang; Peng, Bao-Gang; Liang, Li-Jian; Hua, Yun-Peng

    2018-04-24

    Embryonic Liver Fodrin (ELF) is an adaptor protein of transforming growth factor (TGF-β) signaling cascade. Disruption of ELF results in mislocalization of Smad3 and Smad4, leading to compromised TGF-β signaling. c-Myc is an important oncogenic transcription factor, and the disruption of TGF-β signaling promotes c-Myc-induced hepatocellular carcinoma (HCC) carcinogenesis. However, the prognostic significance of c-Myc in HCC is less understood METHODS: The expression of c-Myc protein and mRNA were measured by immunohistochemistry (IHC) and qRT- PCR, respectively. IHC was performed to detect TGF-β1 and ELF expression in HCC tissues. Their relationship with clinicopathological factors and overall survival (OS) and disease free survival (DFS) were examined. The expression of c-Myc protein and mRNA in HCC tissues were significantly higher in HCC area than those in normal liver tissues. However, the expression were low compared with those adjacent to HCC area. c-Myc protein was independently predictive of DFS and OS, and it was negatively correlated with tumor size (P = 0.031), tumor number (P = 0.038), and recurrence (P = 0.001). Low c-Myc expression was associated with short-term recurrence and poor prognosis. The predictive value of c-Myc combined with TGF-β1 or/and ELF was higher than that of any other single marker. Low c-Myc, high TGF-β1 or/and low ELF expression was associated with the worst DFS and OS. Low expression of c-Myc protein predicts poor outcomes in patients with HCC with hepatectomy. The combination of the expression of c-Myc, TGF-β1, and ELF can be used to accurately predict outcomes of patients with HCC.

  20. Endogenous c-Myc is essential for p53-induced apoptosis in response to DNA damage in vivo

    NARCIS (Netherlands)

    Phesse, T. J.; Myant, K. B.; Cole, A. M.; Ridgway, R. A.; Pearson, H.; Muncan, V.; van den Brink, G. R.; Vousden, K. H.; Sears, R.; Vassilev, L. T.; Clarke, A. R.; Sansom, O. J.

    2014-01-01

    Recent studies have suggested that C-MYC may be an excellent therapeutic cancer target and a number of new agents targeting C-MYC are in preclinical development. Given most therapeutic regimes would combine C-MYC inhibition with genotoxic damage, it is important to assess the importance of C-MYC

  1. Mitochondrial structure, function and dynamics are temporally controlled by c-Myc.

    Directory of Open Access Journals (Sweden)

    J Anthony Graves

    Full Text Available Although the c-Myc (Myc oncoprotein controls mitochondrial biogenesis and multiple enzymes involved in oxidative phosphorylation (OXPHOS, the coordination of these events and the mechanistic underpinnings of their regulation remain largely unexplored. We show here that re-expression of Myc in myc-/- fibroblasts is accompanied by a gradual accumulation of mitochondrial biomass and by increases in membrane polarization and mitochondrial fusion. A correction of OXPHOS deficiency is also seen, although structural abnormalities in electron transport chain complexes (ETC are not entirely normalized. Conversely, the down-regulation of Myc leads to a gradual decrease in mitochondrial mass and a more rapid loss of fusion and membrane potential. Increases in the levels of proteins specifically involved in mitochondrial fission and fusion support the idea that Myc affects mitochondrial mass by influencing both of these processes, albeit favoring the latter. The ETC defects that persist following Myc restoration may represent metabolic adaptations, as mitochondrial function is re-directed away from producing ATP to providing a source of metabolic precursors demanded by the transformed cell.

  2. c-MYC G-quadruplex binding by the RNA polymerase I inhibitor BMH-21 and analogues revealed by a combined NMR and biochemical Approach.

    Science.gov (United States)

    Musso, Loana; Mazzini, Stefania; Rossini, Anna; Castagnoli, Lorenzo; Scaglioni, Leonardo; Artali, Roberto; Di Nicola, Massimo; Zunino, Franco; Dallavalle, Sabrina

    2018-03-01

    Pyridoquinazolinecarboxamides have been reported as RNA polymerase I inhibitors and represent a novel class of potential antitumor agents. BMH-21, was reported to intercalate with GC-rich rDNA, resulting in nucleolar stress as a primary mechanism of cytotoxicity. The interaction of BMH-21 and analogues with DNA G-quadruplex structures was studied by NMR and molecular modelling. The cellular response was investigated in a panel of human tumor cell lines and protein expression was examined by Western Blot analysis. We explored the ability of BMH-21 and its analogue 2 to bind to G-quadruplex present in the c-MYC promoter, by NMR and molecular modelling studies. We provide evidence that both compounds are not typical DNA intercalators but are effective binders of the tested G-quadruplex. The interaction with c-MYC G-quadruplex was reflected in down-regulation of c-Myc expression in human tumor cells. The inhibitory effect was almost complete in lymphoma cells SUDHL4 characterized by overexpression of c-Myc protein. This downregulation reflected an early and persistent modulation of cMyc mRNA. Given the relevance of c-MYC in regulation of ribosome biogenesis, it is conceivable that the inhibition of c-MYC contributes to the perturbation of nuclear functions and RNA polymerase I activity. Similar experiments with CX-5461, another RNA polymerase I transcription inhibitor, indicate the same behaviour in G-quadruplex stabilization. Our results support the hypothesis that BMH-21 and analogue compounds share the same mechanism, i.e. G-quadruplex binding as a primary event of a cascade leading to inhibition of RNA polymerase I and apoptosis. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Polymerase chain reaction-based detection of myc transduction in feline leukemia virus-infected cats.

    Science.gov (United States)

    Sumi, Ryosuke; Miyake, Ariko; Endo, Taiji; Ohsato, Yoshiharu; Ngo, Minh Ha; Nishigaki, Kazuo

    2018-04-01

    Feline lymphomas are associated with the transduction and activation of cellular proto-oncogenes, such as c-myc, by feline leukemia virus (FeLV). We describe a polymerase chain reaction assay for detection of myc transduction usable in clinical diagnosis. The assay targets c-myc exons 2 and 3, which together result in a FeLV-specific fusion gene following c-myc transduction. When this assay was conducted on FeLV-infected feline tissues submitted for clinical diagnosis of tumors, myc transduction was detected in 14% of T-cell lymphoma/leukemias. This newly established system could become a useful diagnostic tool in veterinary medicine.

  4. Macrocyclic peptides decrease c-Myc protein levels and reduce prostate cancer cell growth.

    Science.gov (United States)

    Mukhopadhyay, Archana; Hanold, Laura E; Thayele Purayil, Hamsa; Gisemba, Solomon A; Senadheera, Sanjeewa N; Aldrich, Jane V

    2017-08-03

    The oncoprotein c-Myc is often overexpressed in cancer cells, and the stability of this protein has major significance in deciding the fate of a cell. Thus, targeting c-Myc levels is an attractive approach for developing therapeutic agents for cancer treatment. In this study, we report the anti-cancer activity of the macrocyclic peptides [D-Trp]CJ-15,208 (cyclo[Phe-D-Pro-Phe-D-Trp]) and the natural product CJ-15,208 (cyclo[Phe-D-Pro-Phe-Trp]). [D-Trp]CJ-15,208 reduced c-Myc protein levels in prostate cancer cells and decreased cell proliferation with IC 50 values ranging from 2.0 to 16 µM in multiple PC cell lines. [D-Trp]CJ-15,208 induced early and late apoptosis in PC-3 cells following 48 hours treatment, and growth arrest in the G2 cell cycle phase following both 24 and 48 hours treatment. Down regulation of c-Myc in PC-3 cells resulted in loss of sensitivity to [D-Trp]CJ-15,208 treatment, while overexpression of c-Myc in HEK-293 cells imparted sensitivity of these cells to [D-Trp]CJ-15,208 treatment. This macrocyclic tetrapeptide also regulated PP2A by reducing the levels of its phosphorylated form which regulates the stability of cellular c-Myc protein. Thus [D-Trp]CJ-15,208 represents a new lead compound for the potential development of an effective treatment of prostate cancer.

  5. Association Between Amplification and Expression of C-MYC Gene and Clinicopathological Characteristics of Stomach Cancer.

    Science.gov (United States)

    Khaleghian, Malihea; Jahanzad, Issa; Shakoori, Abbas; Emami Razavi, Amirnader; Azimi, Cyrus

    2016-02-01

    The incidence rate of gastric cancer in western countries has shown a remarkable decline in the recent years while it is still the most common cancer among males in Iran. The proto-oncogene MYC, located at 8q24.1, regulates almost 15% of human genes and is activated in 20% of all tumors. The amplification of MYC and overexpression of its protein product are observed in 15 - 30% of gastric neoplasias. The objective of this study was to find the preferences of Chromogenic In Situ Hybridization (CISH) and Immunohistochemistry (IHC) in diagnosis and prognosis of gastric cancer. We studied 102 samples of gastric cancer in Iran and all the patients had undergone primary surgical resection at the Cancer Institute Hospital, Tehran University of Medical Sciences. The CISH and IHC techniques were applied for all our samples. All of the samples had adenocarcinoma gastric cancer and were selected randomly. Also, the type of study was cross sectional. The sample size was 100 patients. Our data revealed that both diffuse and intestinal types of gastric cancer occurred significantly more in males than females. Our results showed that there was an indication of some correlation between grades and CISH, although the difference was not significant. Our data also showed that CISH positive patients (43%) were more frequent compared to IHC positive patients (14.7%). There was a correlation between CISH and IHC. These results revealed that there was a significant difference between grades and IHC. There was also no statistical difference between CISH amplification in diffuse and intestinal types. From the results, it could be concluded that for administration of the treatment of stomach cancer, and progress and prognosis of tumor, which is important for patients and clinicians, the CISH is a better and more feasible test than IHC, in regards to sensitivity and specificity.

  6. Myc inhibition is effective against glioma and reveals a role for Myc in proficient mitosis.

    Science.gov (United States)

    Annibali, Daniela; Whitfield, Jonathan R; Favuzzi, Emilia; Jauset, Toni; Serrano, Erika; Cuartas, Isabel; Redondo-Campos, Sara; Folch, Gerard; Gonzàlez-Juncà, Alba; Sodir, Nicole M; Massó-Vallés, Daniel; Beaulieu, Marie-Eve; Swigart, Lamorna B; Mc Gee, Margaret M; Somma, Maria Patrizia; Nasi, Sergio; Seoane, Joan; Evan, Gerard I; Soucek, Laura

    2014-08-18

    Gliomas are the most common primary tumours affecting the adult central nervous system and respond poorly to standard therapy. Myc is causally implicated in most human tumours and the majority of glioblastomas have elevated Myc levels. Using the Myc dominant negative Omomyc, we previously showed that Myc inhibition is a promising strategy for cancer therapy. Here, we preclinically validate Myc inhibition as a therapeutic strategy in mouse and human glioma, using a mouse model of spontaneous multifocal invasive astrocytoma and its derived neuroprogenitors, human glioblastoma cell lines, and patient-derived tumours both in vitro and in orthotopic xenografts. Across all these experimental models we find that Myc inhibition reduces proliferation, increases apoptosis and remarkably, elicits the formation of multinucleated cells that then arrest or die by mitotic catastrophe, revealing a new role for Myc in the proficient division of glioma cells.

  7. USP10 Antagonizes c-Myc Transcriptional Activation through SIRT6 Stabilization to Suppress Tumor Formation

    Directory of Open Access Journals (Sweden)

    Zhenghong Lin

    2013-12-01

    Full Text Available The reduced protein expression of SIRT6 tumor suppressor is involved in tumorigenesis. The molecular mechanisms underlying SIRT6 protein downregulation in human cancers remain unknown. Using a proteomic approach, we have identified the ubiquitin-specific peptidase USP10, another tumor suppressor, as one of the SIRT6-interacting proteins. USP10 suppresses SIRT6 ubiquitination to protect SIRT6 from proteasomal degradation. USP10 antagonizes the transcriptional activity of the c-Myc oncogene through SIRT6, as well as p53, to inhibit cell-cycle progression, cancer cell growth, and tumor formation. To support this conclusion, we detected significant reductions in both USP10 and SIRT6 protein expression in human colon cancers. Our study discovered crosstalk between two tumor-suppressive genes in regulating cell-cycle progression and proliferation and showed that dysregulated USP10 function promotes tumorigenesis through SIRT6 degradation.

  8. The effect of Glut1 and c-myc on prognosis in esophageal squamous cell carcinoma of Kazakh and Han patients.

    Science.gov (United States)

    Zhou, Ya-Xing; Zhou, Ke-Ming; Liu, Qian; Wang, Hui; Wang, Wen; Shi, Yi; Ma, Yu-Qing

    2018-04-09

    Glucose transporter type 1 (Glut1) plays a crucial role in cancer-specific metabolism. We explored the expression of Glut1 and c-myc, the relationship between them and the effect of Glut1, c-myc on prognosis in esophageal squamous cell carcinoma. Immunohistochemistry was used to examine the expression of Glut1 and c-myc. χ 2 test analyzes the relationship between c-myc, Glut1 and pathological parameters. Spearman correlation analyzes the relationship between c-myc and Glut1. Survival analysis was used to investigate the effect of Glut1 and c-myc on prognosis. Glut1 positivity was associated with tumor size (p C-myc positivity was associated with tumor location (p = 0.015), depth of invasion (p = 0.022) and lymph node metastasis (p = 0.035). There was a positive correlation between c-myc and Glut1 (r = 0.321). Patients with Glut1 c-myc co-expression had poorer prognosis. Inhibiting Glut1 c-myc co-expression may improve the prognosis of esophageal squamous cell carcinoma.

  9. Interaction of MYC with host cell factor-1 is mediated by the evolutionarily conserved Myc box IV motif.

    Science.gov (United States)

    Thomas, L R; Foshage, A M; Weissmiller, A M; Popay, T M; Grieb, B C; Qualls, S J; Ng, V; Carboneau, B; Lorey, S; Eischen, C M; Tansey, W P

    2016-07-07

    The MYC family of oncogenes encodes a set of three related transcription factors that are overexpressed in many human tumors and contribute to the cancer-related deaths of more than 70,000 Americans every year. MYC proteins drive tumorigenesis by interacting with co-factors that enable them to regulate the expression of thousands of genes linked to cell growth, proliferation, metabolism and genome stability. One effective way to identify critical co-factors required for MYC function has been to focus on sequence motifs within MYC that are conserved throughout evolution, on the assumption that their conservation is driven by protein-protein interactions that are vital for MYC activity. In addition to their DNA-binding domains, MYC proteins carry five regions of high sequence conservation known as Myc boxes (Mb). To date, four of the Mb motifs (MbI, MbII, MbIIIa and MbIIIb) have had a molecular function assigned to them, but the precise role of the remaining Mb, MbIV, and the reason for its preservation in vertebrate Myc proteins, is unknown. Here, we show that MbIV is required for the association of MYC with the abundant transcriptional coregulator host cell factor-1 (HCF-1). We show that the invariant core of MbIV resembles the tetrapeptide HCF-binding motif (HBM) found in many HCF-interaction partners, and demonstrate that MYC interacts with HCF-1 in a manner indistinguishable from the prototypical HBM-containing protein VP16. Finally, we show that rationalized point mutations in MYC that disrupt interaction with HCF-1 attenuate the ability of MYC to drive tumorigenesis in mice. Together, these data expose a molecular function for MbIV and indicate that HCF-1 is an important co-factor for MYC.

  10. Driving gradual endogenous c-myc overexpression by flow-sorting: intracellular signaling and tumor cell phenotype correlate with oncogene expression

    DEFF Research Database (Denmark)

    Knudsen, Kasper Jermiin; Holm, G.M.N.; Krabbe, J.S.

    2009-01-01

    Insulin-exposed rat mammary cancer cells were flow sorted based on a c-myc reporter plasmid encoding a destabilized green fluorescent protein. Sorted cells exhibited gradual increases in c-myc levels. Cells overexpressing c-myc by only 10% exhibited phenotypic changes attributable to c-myc overex...

  11. MYCT1-TV, A Novel MYCT1 Transcript, Is Regulated by c-Myc and May Participate in Laryngeal Carcinogenesis

    Science.gov (United States)

    Fu, Shuang; Guo, Yan; Chen, Hong; Xu, Zhen-Ming; Qiu, Guang-Bin; Zhong, Ming; Sun, Kai-Lai; Fu, Wei-Neng

    2011-01-01

    Background MYCT1, a putative target of c-Myc, is a novel candidate tumor suppressor gene cloned from laryngeal squamous cell carcinoma (LSCC). Its transcriptional regulation and biological effects on LSCC have not been clarified. Methodology/Principal Findings Using RACE assay, we cloned a 1106 bp transcript named Myc target 1 transcript variant 1 (MYCT1-TV) and confirmed its transcriptional start site was located at 140 bp upstream of the ATG start codon of MYCT1-TV. Luciferase, electrophoretic mobility shift and chromatin immunoprecipitation assays confirmed c-Myc could regulate the promoter activity of MYCT1-TV by specifically binding to the E-box elements within −886 to −655 bp region. These results were further verified by site-directed mutagenesis and RNA interference (RNAi) assays. MYCT1-TV and MYCT1 expressed lower in LSCC than those in paired adjacent normal laryngeal tissues, and overexpression of MYCT1-TV and MYCT1 could inhibit cell proliferation and invasion and promote apoptosis in LSCC cells. Conclusions/Significance Our data indicate that MYCT1-TV, a novel MYCT1 transcript, is regulated by c-Myc and down-regulation of MYCT1-TV/MYCT1 could contribute to LSCC development and function. PMID:21998677

  12. N-Myc and GCN5 regulate significantly overlapping transcriptional programs in neural stem cells.

    Directory of Open Access Journals (Sweden)

    Verónica Martínez-Cerdeño

    Full Text Available Here we examine the functions of the Myc cofactor and histone acetyltransferase, GCN5/KAT2A, in neural stem and precursor cells (NSC using a conditional knockout approach driven by nestin-cre. Mice with GCN5-deficient NSC exhibit a 25% reduction in brain mass with a microcephaly phenotype similar to that observed in nestin-cre driven knockouts of c- or N-myc. In addition, the loss of GCN5 inhibits precursor cell proliferation and reduces their populations in vivo, as does loss of N-myc. Gene expression analysis indicates that about one-sixth of genes whose expression is affected by loss of GCN5 are also affected in the same manner by loss of N-myc. These findings strongly support the notion that GCN5 protein is a key N-Myc transcriptional cofactor in NSC, but are also consistent with recruitment of GCN5 by other transcription factors and the use by N-Myc of other histone acetyltransferases. Putative N-Myc/GCN5 coregulated transcriptional pathways include cell metabolism, cell cycle, chromatin, and neuron projection morphogenesis genes. GCN5 is also required for maintenance of histone acetylation both at its putative specific target genes and at Myc targets. Thus, we have defined an important role for GCN5 in NSC and provided evidence that GCN5 is an important Myc transcriptional cofactor in vivo.

  13. Inversed relationship between CD44 variant and c-Myc due to oxidative stress-induced canonical Wnt activation

    International Nuclear Information System (INIS)

    Yoshida, Go J.; Saya, Hideyuki

    2014-01-01

    Highlights: •CD44 variant8–10 and c-Myc are inversely expressed in gastric cancer cells. •Redox-stress enhances c-Myc expression via canonical Wnt signal. •CD44v, but not CD44 standard, suppresses redox stress-induced Wnt activation. •CD44v expression promotes both transcription and proteasome degradation of c-Myc. •Inversed expression pattern between CD44v and c-Myc is often recognized in vivo. -- Abstract: Cancer stem-like cells express high amount of CD44 variant8-10 which protects cancer cells from redox stress. We have demonstrated by immunohistochemical analysis and Western blotting, and reverse-transcription polymerase chain reaction, that CD44 variant8-10 and c-Myc tend to show the inversed expression manner in gastric cancer cells. That is attributable to the oxidative stress-induced canonical Wnt activation, and furthermore, the up-regulation of the downstream molecules, one of which is oncogenic c-Myc, is not easily to occur in CD44 variant-positive cancer cells. We have also found out that CD44v8-10 expression is associated with the turn-over of the c-Myc with the experiments using gastric cancer cell lines. This cannot be simply explained by the model of oxidative stress-induced Wnt activation. CD44v8-10-positive cancer cells are enriched at the invasive front. Tumor tissue at the invasive area is considered to be composed of heterogeneous cellular population; dormant cancer stem-like cells with CD44v8-10 high / Fbw7 high / c-Myc low and proliferative cancer stem-like cells with CD44v8-10 high / Fbw7 low / c-Myc high

  14. Identification of a c-Jun N-terminal kinase-2-dependent signal amplification cascade that regulates c-Myc levels in ras transformation

    DEFF Research Database (Denmark)

    Mathiasen, D.P.; Egebjerg, C.; Andersen, S.H.

    2012-01-01

    are essential for ras transformation. Previous studies show that ERK-mediated serine 62 phosphorylation protects c-Myc from proteasomal degradation. ERK is, however, not alone sufficient to stabilize c-Myc but requires the cooperation of cancerous inhibitor of protein phosphatase 2A (CIP2A), an oncogene...... that counteracts protein phosphatase 2A-mediated dephosphorylation of c-Myc. Here we show that JNK2 regulates Cip2a transcription via ATF2. ATF2 and c-Myc cooperate to activate the transcription of ATF3. Remarkably, not only ectopic JNK2, but also ectopic ATF2, CIP2A, c-Myc and ATF3 are sufficient to rescue...... the defective ras transformation of JNK2-deficient cells. Thus, these data identify the key signal converging point of JNK2 and ERK pathways and underline the central role of CIP2A in ras transformation.Oncogene advance online publication, 27 June 2011; doi:10.1038/onc.2011.230....

  15. THE MYC FAMILY OF ONCOGENES AND THEIR PRESENCE AND IMPORTANCE IN SMALL-CELL LUNG-CARCINOMA AND OTHER TUMOR TYPES

    NARCIS (Netherlands)

    DEVRIES, EGE; MULDER, NH

    1993-01-01

    The myc family of cellular oncogenes, c - myr, N - myc, encodes three highly related, cell cycle specific, nuclear phosphoproteins. All are able to transform primary rat embryo fibroblasts when cotransfected with the c - ras oncogene. Myc family genes am differentially expressed with respect to

  16. The 5T mouse multiple myeloma model: Absence of c-myc oncogene rearrangement in early transplant generations

    NARCIS (Netherlands)

    Radl, J.; Punt, Y.A.; Enden-Vieveen, M.H.M. van den; Bentvelzen, P.A.J.; Bakkus, M.H.C.; Akker T., W. van den; Benner, R.

    1990-01-01

    Consistent chromosomal translocations involving the c-myc cellular oncogene and one of the three immunoglobulin loci are typical for human Burkitt's lymphoma, induced mouse plasmacytoma (MPC) and spontaneously arising rat immunocytoma (RIC). Another plasma cell malignancy, multiple myeloma (MM),

  17. Combined use of nuclear phosphoprotein c-Myc and cellular phosphoprotein p53 for hepatocellular carcinoma detection in high-risk chronic hepatitis C patients.

    Science.gov (United States)

    Attallah, A M; El-Far, M; Abdelrazek, M A; Omran, M M; Attallah, A A; Elkhouly, A A; Elkenawy, H M; Farid, K

    2017-10-01

    Hepatocellular carcinoma (HCC) is a multistage process resulting from various genetic changes. We aimed to determine nuclear phosphoprotein c-Myc and cellular phosphoprotein p53 expression and to evaluate their importance in HCC diagnosis. One hundred and twenty chronic hepatitis C (CHC) patients (60 non-HCC CHC patients and 60 HCC patients who had a single small (c-Myc and p53 were identified in liver tissues and serum samples using immunostaining, western blot and ELISA. Immunohistochemical detection of c-Myc and p53 with monospecific antibodies revealed intense and diffuse cytoplasmic staining patterns. Accumulated mutant proteins, released from tumour cells into the extracellular serum, were detected at 62 KDa, for c-Myc, and 53 KDa, for p53, using western blotting. In contrast to alpha feto-protein, there was a significant increase (p c-Myc (86.7% vs. 6.7%) and p53 (78.3% vs. 8.3%) in the malignant vs. non-malignant patients. The parallel combination of c-Myc and p53 reach the absolute sensitivity (100%), for more accurate and reliable HCC detection (specificity was 87%). c-Myc and p53 are potential HCC diagnostic biomarkers, and convenient combinations of them could improve diagnostic accuracy of HCC.

  18. New Aspects of an Old Drug – Diclofenac Targets MYC and Glucose Metabolism in Tumor Cells

    Science.gov (United States)

    Gottfried, Eva; Lang, Sven A.; Renner, Kathrin; Bosserhoff, Anja; Gronwald, Wolfram; Rehli, Michael; Einhell, Sabine; Gedig, Isabel; Singer, Katrin; Seilbeck, Anton; Mackensen, Andreas; Grauer, Oliver; Hau, Peter; Dettmer, Katja; Andreesen, Reinhard; Oefner, Peter J.; Kreutz, Marina

    2013-01-01

    Non-steroidal anti-inflammatory drugs such as diclofenac exhibit potent anticancer effects. Up to now these effects were mainly attributed to its classical role as COX-inhibitor. Here we show novel COX-independent effects of diclofenac. Diclofenac significantly diminished MYC expression and modulated glucose metabolism resulting in impaired melanoma, leukemia, and carcinoma cell line proliferation in vitro and reduced melanoma growth in vivo. In contrast, the non-selective COX inhibitor aspirin and the COX-2 specific inhibitor NS-398 had no effect on MYC expression and glucose metabolism. Diclofenac significantly decreased glucose transporter 1 (GLUT1), lactate dehydrogenase A (LDHA), and monocarboxylate transporter 1 (MCT1) gene expression in line with a decrease in glucose uptake and lactate secretion. A significant intracellular accumulation of lactate by diclofenac preceded the observed effect on gene expression, suggesting a direct inhibitory effect of diclofenac on lactate efflux. While intracellular lactate accumulation impairs cellular proliferation and gene expression, it does not inhibit MYC expression as evidenced by the lack of MYC regulation by the MCT inhibitor α-cyano-4-hydroxycinnamic acid. Finally, in a cell line with a tetracycline-regulated c-MYC gene, diclofenac decreased proliferation both in the presence and absence of c-MYC. Thus, diclofenac targets tumor cell proliferation via two mechanisms, that is inhibition of MYC and lactate transport. Based on these results, diclofenac holds potential as a clinically applicable MYC and glycolysis inhibitor supporting established tumor therapies. PMID:23874405

  19. Defective double-strand DNA break repair and chromosomal translocations by MYC overexpression.

    Science.gov (United States)

    Karlsson, Asa; Deb-Basu, Debabrita; Cherry, Athena; Turner, Stephanie; Ford, James; Felsher, Dean W

    2003-08-19

    DNA repair mechanisms are essential for the maintenance of genomic integrity. Disruption of gene products responsible for DNA repair can result in chromosomal damage. Improperly repaired chromosomal damage can result in the loss of chromosomes or the generation of chromosomal deletions or translocations, which can lead to tumorigenesis. The MYC protooncogene is a transcription factor whose overexpression is frequently associated with human neoplasia. MYC has not been previously implicated in a role in DNA repair. Here we report that the overexpression of MYC disrupts the repair of double-strand DNA breaks, resulting in a several-magnitude increase in chromosomal breaks and translocations. We found that MYC inhibited the repair of gamma irradiation DNA breaks in normal human cells and blocked the repair of a single double-strand break engineered to occur in an immortal cell line. By spectral karyotypic analysis, we found that MYC even within one cell division cycle resulted in a several-magnitude increase in the frequency of chromosomal breaks and translocations in normal human cells. Hence, MYC overexpression may be a previously undescribed example of a dominant mutator that may fuel tumorigenesis by inducing chromosomal damage.

  20. Melatonin disturbs SUMOylation mediated crosstalk between c-Myc and Nestin via MT1 activation and promotes the sensitivity of Paclitaxel in brain cancer stem cells.

    Science.gov (United States)

    Lee, Hyemin; Lee, Hyo-Jung; Jung, Ji Hoon; Shin, Eun Ah; Kim, Sung-Hoon

    2018-04-14

    Here the underlying antitumor mechanism of melatonin and its potency as a sensitizer of Paclitaxel was investigated in X02 cancer stem cells. Melatonin suppressed sphere formation and induced G2/M arrest in X02 cells expressing Nestin, CD133, CXCR4 and SOX-2 as biomarkers of stemness. Furthermore, melatonin reduced the expression of CDK2, CDK4, cyclin D1, cyclin E, and c-Myc and upregulated cyclin B1 in X02 cells. Notably, genes of c-Myc related mRNAs were differentially expressed in melatonin treated X02 cells by microarray analysis. Consistently, melatonin reduced the expression of c-Myc at mRNA and protein levels, which was blocked by MG132. Of note, overexpression of c-Myc increased the expression of Nestin, while overexpression of Nestin enhanced c-Myc through crosstalk despite different locations, nucleus and cytoplasm. Interestingly, melatonin attenuated small ubiquitin-related modifier-1 (SUMO-1) more than SUMO-2 or SUMO-3 and disturbed nuclear translocation of Nestin for direct binding to c-Myc by SUMOylation of SUMO-1 protein by immunofluorescence and immunoprecipitation. Also, melatonin reduced trimethylated histone H3K4me3 and H3K36me3 more than dimethylation in X02 cells by Western blotting and Chromatin immunoprecipitation assay. Notably, melatonin upregulated MT1, not MT2, in X02 cells and melatonin receptor inhibitor Luzindole blocked the ability of melatonin to decrease the expression of Nestin, p-c-Myc(S62) and c-Myc. Furthermore, melatonin promoted cytotoxicity, sub G1 accumulation and apoptotic body formation by Paclitaxcel in X02 cells. Taken together, these findings suggest that melatonin inhibits stemness via suppression of c-Myc, Nestin, and histone methylation via MT1 activation and promotes anticancer effect of Paclitaxcel in brain cancer stem cells. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  1. Inversed relationship between CD44 variant and c-Myc due to oxidative stress-induced canonical Wnt activation

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Go J., E-mail: medical21go@yahoo.co.jp; Saya, Hideyuki

    2014-01-10

    Highlights: •CD44 variant8–10 and c-Myc are inversely expressed in gastric cancer cells. •Redox-stress enhances c-Myc expression via canonical Wnt signal. •CD44v, but not CD44 standard, suppresses redox stress-induced Wnt activation. •CD44v expression promotes both transcription and proteasome degradation of c-Myc. •Inversed expression pattern between CD44v and c-Myc is often recognized in vivo. -- Abstract: Cancer stem-like cells express high amount of CD44 variant8-10 which protects cancer cells from redox stress. We have demonstrated by immunohistochemical analysis and Western blotting, and reverse-transcription polymerase chain reaction, that CD44 variant8-10 and c-Myc tend to show the inversed expression manner in gastric cancer cells. That is attributable to the oxidative stress-induced canonical Wnt activation, and furthermore, the up-regulation of the downstream molecules, one of which is oncogenic c-Myc, is not easily to occur in CD44 variant-positive cancer cells. We have also found out that CD44v8-10 expression is associated with the turn-over of the c-Myc with the experiments using gastric cancer cell lines. This cannot be simply explained by the model of oxidative stress-induced Wnt activation. CD44v8-10-positive cancer cells are enriched at the invasive front. Tumor tissue at the invasive area is considered to be composed of heterogeneous cellular population; dormant cancer stem-like cells with CD44v8-10 {sup high}/ Fbw7 {sup high}/ c-Myc {sup low} and proliferative cancer stem-like cells with CD44v8-10 {sup high}/ Fbw7 {sup low}/ c-Myc {sup high}.

  2. cAMP-Dependent Protein Kinase A (PKA)-Mediated c-Myc Degradation Is Dependent on the Relative Proportion of PKA-I and PKA-II Isozymes.

    Science.gov (United States)

    Liu, Qingyuan; Nguyen, Eric; Døskeland, Stein; Ségal-Bendirdjian, Évelyne

    2015-09-01

    The transcription factor c-Myc regulates numerous target genes that are important for multiple cellular processes such as cell growth and differentiation. It is commonly deregulated in leukemia. Acute promyelocytic leukemia (APL) is characterized by a blockade of granulocytic differentiation at the promyelocyte stage. Despite the great success of all-trans retinoic acid (ATRA)-based therapy, which results in a clinical remission by inducing promyelocyte maturation, a significant number of patients relapse due to the development of ATRA resistance. A significant role has been ascribed to the cAMP/cAMP-dependent protein kinase A (PKA) signaling pathway in retinoid treatment since PKA activation is able to restore differentiation in some ATRA-resistant cells and eradicate leukemia-initiating cells in vivo. In this study, using NB4 APL cell variants resistant to ATRA-induced differentiation, we reveal distinct functional roles of the two PKA isozymes, PKA type I (PKA-I) and PKA-type II (PKA-II), on the steady-state level of c-Myc protein, providing a likely mechanism by which cAMP-elevating agents can restore differentiation in ATRA maturation-resistant APL cells. Therefore, both the inhibition of c-Myc activity and the PKA-I/PKA-II ratio should be taken into account if cAMP-based therapy is considered in the clinical management of APL. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

  3. Calmodulin-mediated activation of Akt regulates survival of c-Myc-overexpressing mouse mammary carcinoma cells.

    Science.gov (United States)

    Deb, Tushar B; Coticchia, Christine M; Dickson, Robert B

    2004-09-10

    c-Myc-overexpressing mammary epithelial cells are proapoptotic; their survival is strongly promoted by epidermal growth factor (EGF). We now demonstrate that EGF-induced Akt activation and survival in transgenic mouse mammary tumor virus-c-Myc mouse mammary carcinoma cells are both calcium/calmodulin-dependent. Akt activation is abolished by the phospholipase C-gamma inhibitor U-73122, by the intracellular calcium chelator BAPTA-AM, and by the specific calmodulin antagonist W-7. These results implicate calcium/calmodulin in the activation of Akt in these cells. In addition, Akt activation by serum and insulin is also inhibited by W-7. EGF-induced and calcium/calmodulin-mediated Akt activation occurs in both tumorigenic and non-tumorigenic mouse and human mammary epithelial cells, independent of their overexpression of c-Myc. These results imply that calcium/calmodulin may be a common regulator of Akt activation, irrespective of upstream receptor activator, mammalian species, and transformation status in mammary epithelial cells. However, only c-Myc-overexpressing mouse mammary carcinoma cells (but not normal mouse mammary epithelial cells) undergo apoptosis in the presence of the calmodulin antagonist W-7, indicating the vital selective role of calmodulin for survival of these cells. Calcium/calmodulin-regulated Akt activation is mediated directly by neither calmodulin kinases nor phosphatidylinositol 3-kinase (PI-3 kinase). Pharmacological inhibitors of calmodulin kinase kinase and calmodulin kinases II and III do not inhibit EGF-induced Akt activation, and calmodulin antagonist W-7 does not inhibit phosphotyrosine-associated PI-3 kinase activation. Akt is, however, co-immunoprecipitated with calmodulin in an EGF-dependent manner, which is inhibited by calmodulin antagonist W-7. We conclude that calmodulin may serve a vital regulatory function to direct the localization of Akt to the plasma membrane for its activation by PI-3 kinase.

  4. Detecção imunoistoquímica das oncoproteínas p21ras, c-myc E p53 no carcinoma hepatocelular e no tecido hepático não-neoplásico Immunohistochemical detection of p21ras, c-myc and p53 oncoproteins in hepatocellular carcinoma and in non-neoplastic liver tissue

    Directory of Open Access Journals (Sweden)

    Vera Lucia Nunes Pannain

    2004-12-01

    Full Text Available RACIONAL: A hepatocarcinogênese é um processo no qual as alterações genéticas e epigenéticas são bem conhecidas em modelos animais, mas carece de estudos no homem. OBJETIVOS: Analisar a freqüência das oncoproteínas p21ras, c-myc e p53 no carcinoma hepatocelular e no fígado não-neoplásico. Verificar ainda a associação destas oncoproteínas com os padrões e graus histológicos, assim como com as infecções pelos vírus das hepatites B e C. MÉTODOS: Foi analisada por método imunoistoquímico a detecção das oncoproteínas p21ras, c-myc e p53 em 47 casos de carcinoma hepatocelular e no tecido não-neoplásico circunjacente ao tumor (40 casos. RESULTADOS: As oncoproteínas p21ras, c-myc e p53 foram detectadas, respectivamente, em 44,7%, 53,2% e 36,2% dos casos de carcinoma hepatocelular. A imunorreatividade do p21ras e c-myc mostrou uma associação significativa. Contudo, não houve associação significativa entre a detecção do p21ras, c-myc e p53 com os diferentes graus e padrões histológicos, nem tampouco com as infecções pelos vírus das hepatites B e C. A mesma associação significativa entre o p21ras e c-myc foi encontrada no tecido não-neoplásico dos casos de cirrose em relação aos que não apresentaram cirrose, enquanto que o p53 foi negativo em todos os casos. CONCLUSÕES: A imunorreatividade das oncoproteínas p21ras, c-myc e p53 corrobora evidências prévias de sua detecção no carcinoma hepatocelular, o que sugere poder haver participação destas proteínas na hepatocarcinogênese humana. A significativa associação entre as proteínas p21ras, c-myc e p53 no carcinoma hepatocelular e na cirrose pode apontar uma interação entre as mesmas, sobretudo na hepatocarcinogênese pela via da cirrose.BACKGROUND: Genetic and epigenetic alterations have been described in animal hepatocarcinogenesis models but need to be studied in human being. AIMS: To assess the immunoreactivity of p21ras, c-myc and p53

  5. Immunodetection of rasP21 and c-myc oncogenes in oral mucosal swab preparation from clove cigarette smokers

    Directory of Open Access Journals (Sweden)

    Silvi Kintawati

    2008-12-01

    Full Text Available Background: Smoking is the biggest factor for oral cavity malignancy. Some carcinogens found in cigar will stimulate epithel cell in oral cavity and cause mechanism disturbance on tissue resistance and produce abnormal genes (oncogenes. Oncogenes ras and myc are found on malignant tumor in oral cavity which are associated with smoking. Purpose: This research is to find the expression of oncogenes rasP21 and c-myc in oral mucosa epithelial of smoker with immunocytochemistry reaction. Methods: An oral mucosal swab was performed to 30 smokers categorized as light, moderate, and chain, and 10 non smokers which was followed by immunocytochemistry reaction using antibody towards oncogene rasP21 and c-myc is reacted to identify the influence of smoking towards malignant tumor in oral cavity. The result is statistically analyzed using Kruskal-Wallis test. Result: Based on the observation result of oncogene rasP21reaction, it shows that there is significant difference between non smoker group and light smoker, compared to moderate and chain smoker group (p < 0.01. On the other side, the observation result of oncogene c-myc indicates that there is no significant difference between the group of non smokers and the group of light, moderate, and chain smokers (p > 0.05. Conclusion: The higher the possibility of oral cavity malignancy and that the antibody for rasP21 oncogene can be used as a marker for early detection of oral cavity malignancy caused by smoking.

  6. SirT1 knockdown potentiates radiation-induced bystander effect through promoting c-Myc activity and thus facilitating ROS accumulation

    International Nuclear Information System (INIS)

    Xie, Yuexia; Tu, Wenzhi; Zhang, Jianghong; He, Mingyuan; Ye, Shuang; Dong, Chen; Shao, Chunlin

    2015-01-01

    Highlights: • γ-Irradiation induced bystander effects between hepatoma cells and hepatocyte cells. • SirT1 played a protective role in regulating this bystander effect. • SirT1 contributed to the protective effects via elimination the accumulation of ROS. • The activity of c-Myc is critical for maintaining the protective role of SirT1. - Abstract: Radiation-induced bystander effect (RIBE) has important implications for secondary cancer risk assessment during cancer radiotherapy, but the bystander signaling processes, especially under hypoxic condition, are still largely unclear. The present study found that micronuclei (MN) formation could be induced in the non-irradiated HL-7702 hepatocyte cells after being treated with the conditioned medium from irradiated hepatoma HepG2 and SK-Hep-1 cells under either normoxia or hypoxia. This bystander response was dramatically diminished or enhanced when the SirT1 gene of irradiated hepatoma cells was overexpressed or knocked down, respectively, especially under hypoxia. Meanwhile, SirT1 knockdown promoted transcriptional activity for c-Myc and facilitated ROS accumulation. But both of the increased bystander responses and ROS generation due to SirT1-knockdown were almost completely suppressed by c-Myc interference. Moreover, ROS scavenger effectively abolished the RIBE triggered by irradiated hepatoma cells even with SirT1 depletion. These findings provide new insights that SirT1 has a profound role in regulating RIBE where a c-Myc-dependent release of ROS may be involved

  7. SirT1 knockdown potentiates radiation-induced bystander effect through promoting c-Myc activity and thus facilitating ROS accumulation

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Yuexia [Institute of Radiation Medicine, Fudan University, Shanghai (China); Central Laboratory, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai (China); Tu, Wenzhi; Zhang, Jianghong; He, Mingyuan; Ye, Shuang; Dong, Chen [Institute of Radiation Medicine, Fudan University, Shanghai (China); Shao, Chunlin, E-mail: clshao@shmu.edu.cn [Institute of Radiation Medicine, Fudan University, Shanghai (China)

    2015-02-15

    Highlights: • γ-Irradiation induced bystander effects between hepatoma cells and hepatocyte cells. • SirT1 played a protective role in regulating this bystander effect. • SirT1 contributed to the protective effects via elimination the accumulation of ROS. • The activity of c-Myc is critical for maintaining the protective role of SirT1. - Abstract: Radiation-induced bystander effect (RIBE) has important implications for secondary cancer risk assessment during cancer radiotherapy, but the bystander signaling processes, especially under hypoxic condition, are still largely unclear. The present study found that micronuclei (MN) formation could be induced in the non-irradiated HL-7702 hepatocyte cells after being treated with the conditioned medium from irradiated hepatoma HepG2 and SK-Hep-1 cells under either normoxia or hypoxia. This bystander response was dramatically diminished or enhanced when the SirT1 gene of irradiated hepatoma cells was overexpressed or knocked down, respectively, especially under hypoxia. Meanwhile, SirT1 knockdown promoted transcriptional activity for c-Myc and facilitated ROS accumulation. But both of the increased bystander responses and ROS generation due to SirT1-knockdown were almost completely suppressed by c-Myc interference. Moreover, ROS scavenger effectively abolished the RIBE triggered by irradiated hepatoma cells even with SirT1 depletion. These findings provide new insights that SirT1 has a profound role in regulating RIBE where a c-Myc-dependent release of ROS may be involved.

  8. Bcl-2 and N-Myc Coexpression Increases IGF-IR and Features of Malignant Growth in Neuroblastoma Cell Lines

    Directory of Open Access Journals (Sweden)

    Rama Jasty

    2001-01-01

    Full Text Available The bcl-2 and c-myc oncogenes cooperate to transform multiple cell types. In the pediatric malignancy NB2, Bcl2 is highly expressed. In tumors with a poor prognosis, N-Myc, a protein homologous to c-Myc, is overexpressed as a result of gene amplification. The present study was designed to determine whether Bcl-2 cooperates with N-Myc to bestow a tumorigenic phenotype to neuroblastoma (NB cells. NB cell lines that at baseline express neither Bcl-2 nor N-Myc were stably transfected to express these gene products. In this model, we found Bcl-2 rescues N-Myc-expressing cells from apoptosis induced by serum withdrawal. Coexpression of Bcl-2 and N-Myc supports growth in low serum conditions and anchorage-independent growth in soft agar. Similarly, in vivo tumorigenic and angiogenic activity was dependent on coexpression. Our data further suggests that the mechanism underlying these changes involves the receptor for insulin growth factor type I (IGF-IR.

  9. Resetting cancer stem cell regulatory nodes upon MYC inhibition.

    Science.gov (United States)

    Galardi, Silvia; Savino, Mauro; Scagnoli, Fiorella; Pellegatta, Serena; Pisati, Federica; Zambelli, Federico; Illi, Barbara; Annibali, Daniela; Beji, Sara; Orecchini, Elisa; Alberelli, Maria Adele; Apicella, Clara; Fontanella, Rosaria Anna; Michienzi, Alessandro; Finocchiaro, Gaetano; Farace, Maria Giulia; Pavesi, Giulio; Ciafrè, Silvia Anna; Nasi, Sergio

    2016-12-01

    MYC deregulation is common in human cancer and has a role in sustaining the aggressive cancer stem cell populations. MYC mediates a broad transcriptional response controlling normal biological programmes, but its activity is not clearly understood. We address MYC function in cancer stem cells through the inducible expression of Omomyc-a MYC-derived polypeptide interfering with MYC activity-taking as model the most lethal brain tumour, glioblastoma. Omomyc bridles the key cancer stemlike cell features and affects the tumour microenvironment, inhibiting angiogenesis. This occurs because Omomyc interferes with proper MYC localization and itself associates with the genome, with a preference for sites occupied by MYC This is accompanied by selective repression of master transcription factors for glioblastoma stemlike cell identity such as OLIG2, POU3F2, SOX2, upregulation of effectors of tumour suppression and differentiation such as ID4, MIAT, PTEN, and modulation of the expression of microRNAs that target molecules implicated in glioblastoma growth and invasion such as EGFR and ZEB1. Data support a novel view of MYC as a network stabilizer that strengthens the regulatory nodes of gene expression networks controlling cell phenotype and highlight Omomyc as model molecule for targeting cancer stem cells. © 2016 The Authors.

  10. c-Myc affects mRNA translation, cell proliferation and progenitor cell function in the mammary gland

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    Trumpp Andreas

    2009-09-01

    Full Text Available Abstract Background The oncoprotein c-Myc has been intensely studied in breast cancer and mouse mammary tumor models, but relatively little is known about the normal physiological role of c-Myc in the mammary gland. Here we investigated functions of c-Myc during mouse mammary gland development using a conditional knockout approach. Results Generation of c-mycfl/fl mice carrying the mammary gland-specific WAPiCre transgene resulted in c-Myc loss in alveolar epithelial cells starting in mid-pregnancy. Three major phenotypes were observed in glands of mutant mice. First, c-Myc-deficient alveolar cells had a slower proliferative response at the start of pregnancy, causing a delay but not a block of alveolar development. Second, while milk composition was comparable between wild type and mutant animals, milk production was reduced in mutant glands, leading to slower pup weight-gain. Electron microscopy and polysome fractionation revealed a general decrease in translational efficiency. Furthermore, analysis of mRNA distribution along the polysome gradient demonstrated that this effect was specific for mRNAs whose protein products are involved in milk synthesis. Moreover, quantitative reverse transcription-polymerase chain reaction analysis revealed decreased levels of ribosomal RNAs and ribosomal protein-encoding mRNAs in mutant glands. Third, using the mammary transplantation technique to functionally identify alveolar progenitor cells, we observed that the mutant epithelium has a reduced ability to repopulate the gland when transplanted into NOD/SCID recipients. Conclusion We have demonstrated that c-Myc plays multiple roles in the mouse mammary gland during pregnancy and lactation. c-Myc loss delayed, but did not block proliferation and differentiation in pregnancy. During lactation, lower levels of ribosomal RNAs and proteins were present and translation was generally decreased in mutant glands. Finally, the transplantation studies suggest a role

  11. N-Myc knockdown and apigenin treatment controlled growth of malignant neuroblastoma cells having N-Myc amplification.

    Science.gov (United States)

    Hossain, Md Motarab; Banik, Naren L; Ray, Swapan K

    2013-10-15

    Malignant neuroblastomas mostly occur in children and are frequently associated with N-Myc amplification. Oncogene amplification, which is selective increase in copy number of the oncogene, provides survival advantages in solid tumors including malignant neuroblastoma. We have decreased expression of N-Myc oncogene using short hairpin RNA (shRNA) plasmid to increase anti-tumor efficacy of the isoflavonoid apigenin (APG) in human malignant neuroblastoma SK-N-DZ and SK-N-BE2 cell lines that harbor N-Myc amplification. N-Myc knockdown induced morphological and biochemical features of neuronal differentiation. Combination of N-Myc knockdown and APG most effectively induced morphological and biochemical features of apoptotic death. This combination therapy also prevented cell migration and decreased N-Myc driven survival, angiogenic, and invasive factors. Collectively, N-Myc knockdown and APG treatment is a promising strategy for controlling the growth of human malignant neuroblastoma cell lines that harbor N-Myc amplification. © 2013 Elsevier B.V. All rights reserved.

  12. Detecting and Targeting Oncogenic Myc in Breast Cancer

    Science.gov (United States)

    2007-06-01

    JPO2, with transforming activity in medulloblastoma cells. Cancer Res 2005, 65(13), 5607–5619. 58. Osthus RC, Karim B, Prescott JE, et al. The Myc...59. Prescott JE, Osthus RC, Lee LA, et al. A novel c-Myc- responsive gene, JPO1, participates in neoplastic transformation. J Biol Chem 2001, 276(51...Department of Medical Genetics and Microbiology , University of Toronto, 112 College Street, Toronto ON M5G 1L6, Canada 3 The Wistar Institute, 3601 Spruce

  13. Nutritional control of gene expression in Drosophila larvae via TOR, Myc and a novel cis-regulatory element

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    Grewal Savraj S

    2010-01-01

    Full Text Available Abstract Background Nutrient availability is a key determinant of eukaryotic cell growth. In unicellular organisms many signaling and transcriptional networks link nutrient availability to the expression of metabolic genes required for growth. However, less is known about the corresponding mechanisms that operate in metazoans. We used gene expression profiling to explore this issue in developing Drosophila larvae. Results We found that starvation for dietary amino acids (AA's leads to dynamic changes in transcript levels of many metabolic genes. The conserved insulin/PI3K and TOR signaling pathways mediate nutrition-dependent growth in Drosophila and other animals. We found that many AA starvation-responsive transcripts were also altered in TOR mutants. In contrast, although PI3K overexpression induced robust changes in the expression of many metabolic genes, these changes showed limited overlap with the AA starvation expression profile. We did however identify a strong overlap between genes regulated by the transcription factor, Myc, and AA starvation-responsive genes, particularly those involved in ribosome biogenesis, protein synthesis and mitochondrial function. The consensus Myc DNA binding site is enriched in promoters of these AA starvation genes, and we found that Myc overexpression could bypass dietary AA to induce expression of these genes. We also identified another sequence motif (Motif 1 enriched in the promoters of AA starvation-responsive genes. We showed that Motif 1 was both necessary and sufficient to mediate transcriptional responses to dietary AA in larvae. Conclusions Our data suggest that many of the transcriptional effects of amino acids are mediated via signaling through the TOR pathway in Drosophila larvae. We also find that these transcriptional effects are mediated through at least two mechanisms: via the transcription factor Myc, and via the Motif 1 cis-regulatory element. These studies begin to elucidate a nutrient

  14. Cdx1 and c-Myc foster the initiation of transdifferentiation of the normal esophageal squamous epithelium toward Barrett's esophagus.

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    Douglas B Stairs

    Full Text Available Barrett's esophagus is a premalignant condition whereby the normal stratified squamous esophageal epithelium undergoes a transdifferentiation program resulting in a simple columnar epithelium reminiscent of the small intestine. These changes are typically associated with the stratified squamous epithelium chronically exposed to acid and bile salts as a result of gastroesophageal reflux disease (GERD. Despite this well-defined epidemiologic association between acid reflux and Barrett's esophagus, the genetic changes that induce this transdifferentiation process in esophageal keratinocytes have remained undefined.To begin to identify the genetic changes responsible for transdifferentiaiton in Barrett's esophagus, we performed a microarray analysis of normal esophageal, Barrett's esophagus and small intestinal biopsy specimens to identify candidate signaling pathways and transcription factors that may be involved. Through this screen we identified the Cdx1 homeodomain transcription factor and the c-myc pathway as possible candidates. Cdx1 and c-myc were then tested for their ability to induce transdifferentiation in immortalized human esophageal keratinocytes using organotypic culturing methods. Analyses of these cultures reveal that c-myc and cdx1 cooperate to induce mucin production and changes in keratin expression that are observed in the epithelium of Barrett's esophagus.These data demonstrate the ability of Cdx1 and c-myc to initiate the earliest stages of transdifferentiation of esophageal keratinocytes toward a cell fate characteristic of Barrett's esophagus.

  15. Distribution of C-myc Antisense Oligonucleotides in Rabbits after Local Delivery by Implanted Gelatin Coated Piatinium -iridium Stent

    Institute of Scientific and Technical Information of China (English)

    张新霞; 庞志功; 崔长琮; 许香广; 胡雪松; 方卫华

    2003-01-01

    Objectives To assess the feasibility, efficiency and tissue distribution of localdelivered c - myc antisense oligonucleotides (ASODN)by implanted gelatin coated Platinium- Iridium (Pt-Ir) stent. Methods Gelatin coated Pt- Ir stentwhich absorbed carboxyfluorescein - 5 - succimidylester (FAM) labeled c -myc ASODN were implantedin the right carotid arteries of 6 rabbits under vision.Blood samples were collected at the indicated times.The target artery、 left carotid artery、 heart、 liver andkidney obtained at 45 minutes、 2 hours and 6hours. The concentration of c - myc ASODN in plasmaand tissues were determined by Thin Layer Fluorome-try. Tissue distribution of c- myc ASODN were as-sessed by fluorescence microscopy. Results At 45min, 2 h, 6 h, the concentration of FAM labeled c -myc ASODN in target artery was 244.39, 194.44,126.94(μg/g tissues) respectively, and the deliveryefficiency were 44.4% 、 35.4% and 23.1% respec-tively. At the same indicated time point, the plasmaconcentration was 8.41, 5. 83, 14.75 (μg/ml) respec-tively. Therefore c -myc ASODN concentrations in thetarget vessel were 29、 33 and 9 -fold higher than thatin the plasma. There was circumferential distribution oflabeled c -myc in the area of highest fluorescein co-inciding with the site of medial dissecting from stent-ing, and the label was most intense in target vesselmedia harvested at 45 min time point and then dis-persed to adventitia. Conclusions Gelatin coated Pt- Ir stent mediated local delivery of c - myc ASODN isfeasible and efficient. The localization of ASODN ismainly in target vessel wall.

  16. 3D view to tumor suppression: Lkb1, polarity and the arrest of oncogenic c-Myc.

    Science.gov (United States)

    Partanen, Johanna I; Nieminen, Anni I; Klefstrom, Juha

    2009-03-01

    Machiavelli wrote, in his famous political treatise Il Principe, about disrupting organization by planting seeds of dissension or by eliminating necessary support elements. Tumor cells do exactly that by disrupting the organized architecture of epithelial cell layers during progression from contained benign tumor to full-blown invasive cancer. However, it is still unclear whether tumor cells primarily break free by activating oncogenes powerful enough to cause chaos or by eliminating tumor suppressor genes guarding the order of the epithelial organization. Studies in Drosophila have exposed genes that encode key regulators of the epithelial apicobasal polarity and which, upon inactivation, cause disorganization of the epithelial layers and promote unscheduled cell proliferation. These polarity regulator/tumor suppressor proteins, which include products of neoplastic tumor suppressor genes (nTSGs), are carefully positioned in polarized epithelial cells to maintain the order of epithelial structures and to impose a restraint on cell proliferation. In this review, we have explored the presence and prevalence of somatic mutations in the human counterparts of Drosophila polarity regulator/tumor suppressor genes across the human cancers. The screen points out LKB1, which is a causal genetic lesion in Peutz-Jeghers cancer syndrome, a gene mutated in certain sporadic cancers and a human homologue of the fly polarity gene par-4. We review the evidence linking Lkb1 protein to polarity regulation in the scope of our recent results suggesting a coupled role for Lkb1 as an architect of organized acinar structures and a suppressor of oncogenic c-Myc. We finally present models to explain how Lkb1-dependent formation of epithelial architecture is coupled to suppression of normal and oncogene-induced proliferation.

  17. Oncogenic c-Myc-induced lymphomagenesis is inhibited non-redundantly by the p19Arf–Mdm2–p53 and RP–Mdm2–p53 pathways

    OpenAIRE

    Meng, X; Carlson, NR; Dong, J; Zhang, Y

    2015-01-01

    The multifaceted oncogene c-Myc plays important roles in the development and progression of human cancer. Recent in vitro and in vivo studies have shown that the p19Arf–Mdm2–p53 and the ribosomal protein (RP)–Mdm2–p53 pathways are both essential in preventing oncogenic c-Myc-induced tumorigenesis. Disruption of each pathway individually by p19Arf deletion or by Mdm2C305F mutation, which disrupts RP-Mdm2 binding, accelerates Eμ-myc transgene-induced pre-B/B-cell lymphoma in mice at seemingly s...

  18. Ku70 acetylation and modulation of c-Myc/ATF4/CHOP signaling axis by SIRT1 inhibition lead to sensitization of HepG2 cells to TRAIL through induction of DR5 and down-regulation of c-FLIP

    DEFF Research Database (Denmark)

    Kim, Mi-Ju; Hong, Kyung-Soo; Kim, Hak-Bong

    2013-01-01

    In this study, we investigated the role of c-Myc/ATF4/CHOP signaling pathway in sensitization of human hepatoma HepG2 cells to TRAIL. Knockdown of SIRT1 or treatment with SIRT1 inhibitor caused the up-regulation of DR5 and down-regulation of c-FLIP through modulation of c-Myc/ATF4/CHOP pathway, a...

  19. Study of C-MYC amplification and expression in Iranian gastric cancer samples using CISH and IHC methods.

    Science.gov (United States)

    Khaleghian, Malihea; Jahanzad, Issa; Shakoori, Abbas; Ardalan, Farid Azmoudeh; Azimi, Cyrus

    2015-01-01

    Gastric cancer is the fourth most frequent malignancy and the second cause of cancer-related mortality worldwide. It has been suggested that in gastric carcinogenesis, the C-MYC gene has an important function. The objective of this study is to establish the preference of Chromogenic in situ hybridization (CISH) and Immunohistochemistry (IHC) in the diagnosis and prognosis of gastric cancer. Samples comprised of 50 randomly selected patients of whom 40 were male and 10 female. To evaluate the MYC copy number and its protein expression, CISH and IHC analyses were performed for 50 gastric adenocarcinomas, in Iran. The location of the tumor in 64% of the patients was the fundus, and in 72% of patients, the tumors were of a diffuse type; 22 samples showed no amplification, and 28 samples were with amplification. MYC immunoreactivity was observed in 13 samples. Twelve samples showed both MYC amplification and MYC immunoreactivity. In addition, among the 28 CISH+ samples, 12 samples had positive signals for IHC and 16 samples had negative signals for IHC. A majority of the IHC-negative patients had no amplification, but only one patient with IHC positive had no amplification. Our conclusion was that for the management and treatment of gastric cancer, and for special attention of clinicians, for prognosis and tumor progression, the CISH was a better and more feasible test than IHC, in regard to the sensitivity and specificity.

  20. Study of C-MYC amplification and expression in Iranian gastric cancer samples using CISH and IHC methods

    Directory of Open Access Journals (Sweden)

    Malihea Khaleghian

    2015-01-01

    Full Text Available Background: Gastric cancer is the fourth most frequent malignancy and the second cause of cancer-related mortality worldwide. It has been suggested that in gastric carcinogenesis, the C-MYC gene has an important function. The objective of this study is to establish the preference of Chromogenic in situ hybridization (CISH and Immunohistochemistry (IHC in the diagnosis and prognosis of gastric cancer. Materials and Methods: Samples comprised of 50 randomly selected patients of whom 40 were male and 10 female. To evaluate the MYC copy number and its protein expression, CISH and IHC analyses were performed for 50 gastric adenocarcinomas, in Iran. Results: The location of the tumor in 64% of the patients was the fundus, and in 72% of patients, the tumors were of a diffuse type; 22 samples showed no amplification, and 28 samples were with amplification. MYC immunoreactivity was observed in 13 samples. Twelve samples showed both MYC amplification and MYC immunoreactivity. In addition, among the 28 CISH+ samples, 12 samples had positive signals for IHC and 16 samples had negative signals for IHC. A majority of the IHC-negative patients had no amplification, but only one patient with IHC positive had no amplification. Conclusion: Our conclusion was that for the management and treatment of gastric cancer, and for special attention of clinicians, for prognosis and tumor progression, the CISH was a better and more feasible test than IHC, in regard to the sensitivity and specificity.

  1. Effects on micronuclei formation of 60-Hz electromagnetic field exposure with ionizing radiation, hydrogen peroxide, or c-Myc overexpression.

    Science.gov (United States)

    Jin, Yeung Bae; Kang, Ga-Young; Lee, Jae Seon; Choi, Jong-Il; Lee, Ju-Woon; Hong, Seung-Cheol; Myung, Sung Ho; Lee, Yun-Sil

    2012-04-01

    Epidemiological studies have demonstrated a possible correlation between exposure to extremely low-frequency magnetic fields (ELF-MF) and cancer. However, this correlation has yet to be definitively confirmed by epidemiological studies. The principal objective of this study was to assess the effects of 60 Hz magnetic fields in a normal cell line system, and particularly in combination with various external factors, via micronucleus (MN) assays. Mouse embryonic fibroblast NIH3T3 cells and human lung fibroblast WI-38 cells were exposed for 4 h to a 60 Hz, 1 mT uniform magnetic field with or without ionizing radiation (IR, 2 Gy), H(2)O(2) (100 μM) and cellular myelocytomatosis oncogene (c-Myc) activation. The results obtained showed no significant differences between the cells exposed to ELF-MF alone and the unexposed cells. Moreover, no synergistic effects were observed when ELF-MF was combined with IR, H(2)O(2), and c-Myc activation. Our results demonstrate that ELF-MF did not enhance MN frequency by IR, H(2)O(2) and c-Myc activation.

  2. Identification of cytotoxic drugs that selectively target tumor cells with MYC overexpression.

    Directory of Open Access Journals (Sweden)

    Anna Frenzel

    Full Text Available Expression of MYC is deregulated in a wide range of human cancers, and is often associated with aggressive disease and poorly differentiated tumor cells. Identification of compounds with selectivity for cells overexpressing MYC would hence be beneficial for the treatment of these tumors. For this purpose we used cell lines with conditional MYCN or c-MYC expression, to screen a library of 80 conventional cytotoxic compounds for their ability to reduce tumor cell viability and/or growth in a MYC dependent way. We found that 25% of the studied compounds induced apoptosis and/or inhibited proliferation in a MYC-specific manner. The activities of the majority of these were enhanced both by c-MYC or MYCN over-expression. Interestingly, these compounds were acting on distinct cellular targets, including microtubules (paclitaxel, podophyllotoxin, vinblastine and topoisomerases (10-hydroxycamptothecin, camptothecin, daunorubicin, doxorubicin, etoposide as well as DNA, RNA and protein synthesis and turnover (anisomycin, aphidicholin, gliotoxin, MG132, methotrexate, mitomycin C. Our data indicate that MYC overexpression sensitizes cells to disruption of specific pathways and that in most cases c-MYC and MYCN overexpression have similar effects on the responses to cytotoxic compounds. Treatment of the cells with topoisomerase I inhibitors led to down-regulation of MYC protein levels, while doxorubicin and the small molecule MYRA-A was found to disrupt MYC-Max interaction. We conclude that the MYC pathway is only targeted by a subset of conventional cytotoxic drugs currently used in the clinic. Elucidating the mechanisms underlying their specificity towards MYC may be of importance for optimizing treatment of tumors with MYC deregulation. Our data also underscores that MYC is an attractive target for novel therapies and that cellular screenings of chemical libraries can be a powerful tool for identifying compounds with a desired biological activity.

  3. Germline Mutations in Mtap Cooperate with Myc to Accelerate Tumorigenesis in Mice.

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    Yuwaraj Kadariya

    Full Text Available The gene encoding the methionine salvage pathway methylthioadenosine phosphorylase (MTAP is a tumor suppressor gene that is frequently inactivated in a wide variety of human cancers. In this study, we have examined if heterozygosity for a null mutation in Mtap (Mtap(lacZ could accelerate tumorigenesis development in two different mouse cancer models, Eμ-myc transgenic and Pten(+/- .Mtap Eμ-myc and Mtap Pten mice were generated and tumor-free survival was monitored over time. Tumors were also examined for a variety of histological and protein markers. In addition, microarray analysis was performed on the livers of Mtap(lacZ/+ and Mtap (+/+ mice.Survival in both models was significantly decreased in Mtap(lacZ/+ compared to Mtap(+/+ mice. In Eµ-myc mice, Mtap mutations accelerated the formation of lymphomas from cells in the early pre-B stage, and these tumors tended to be of higher grade and have higher expression levels of ornithine decarboxylase compared to those observed in control Eµ-myc Mtap(+/+ mice. Surprisingly, examination of Mtap status in lymphomas in Eµ-myc Mtap(lacZ/+ and Eµ-myc Mtap(+/+ animals did not reveal significant differences in the frequency of loss of Mtap protein expression, despite having shorter latency times, suggesting that haploinsufficiency of Mtap may be playing a direct role in accelerating tumorigenesis. Consistent with this idea, microarray analysis on liver tissue from age and sex matched Mtap(+/+ and Mtap(lacZ/+ animals found 363 transcripts whose expression changed at least 1.5-fold (P<0.01. Functional categorization of these genes reveals enrichments in several pathways involved in growth control and cancer.Our findings show that germline inactivation of a single Mtap allele alters gene expression and enhances lymphomagenesis in Eµ-myc mice.

  4. 1,25 dihydroxyvitamin D3 (1,25) regulation of c-myc mRNA in HL-60 leukemia cells

    International Nuclear Information System (INIS)

    Simpson, R.U.; Bresnick, E.H.; Begley, D.A.

    1986-01-01

    Recently, 1,25 was shown to induce differentiation and decrease c-myc levels in HL-60 cells. The authors have confirmed these observations by RNA dot blot analysis. Cells treated with 50 nM 1,25 for 4, 24 and 48 hr showed c-myc mRNA levels of 26, 17 and 15% of control respectively. β-Actin mRNA levels were not altered. To ascertain whether 1, 25 regulated c-myc transcriptionally, an HL-60 nuclear RNA runoff assay was developed. Assay of total nuclei transcriptional activity revealed that 50% of RNA elongation was α-amanitin (0.8 μg/ml) sensitive and was linear with nuclei concentration (0.1-1 x 10 7 nuclei). 1,25 (50 nM) treated (45-96 hr) cells had decreased (approx.40%) total transcription rate relative to control. Decreased total RNA synthesis occurred concomitant with NBT reducing activity. 32 P-RNA runoff transcripts from HL-60 nuclei were hybridized to excess (5 μg DNA was excess) Pst I linearized c-myc and β-actin clones (in pBR322) immobilized on nitrocellulose filter. 32 P-RNA input from 2 x 10 6 to 2 x 10 7 cpm yielded linear hybridization signal. Analysis of blot dot intensity revealed no difference in transcription of c-myc in nuclei from 1,25 dosed or control cells. (myc/actin ratios: 1,25 (50 nM, 72 hr) =1.1 +/- 0.3 and control (72 hr) = 1.0, N=3 or 2 or 3 dots ea). These preliminary data suggest 1,25 does not affect c-myc transcription in HL-60 nuclei and may regulate c-myc mRNA post-transcriptionally

  5. MYC as therapeutic target in leukemia and lymphoma

    Directory of Open Access Journals (Sweden)

    Cortiguera MG

    2015-07-01

    Full Text Available Maria G Cortiguera,1 Ana Batlle-López,1,2 Marta Albajar,1,2 M Dolores Delgado,1,3 Javier León1,3 1Institute of Biomedicine and Biotechnology of Cantabria (IBBTEC, CSIC-University of Cantabria, 2Department of Hemathology, Hospital Universitario Marqués de Valdecilla, 3Department of Molecular Biology, University of Cantabria, Santander, Spain Abstract: MYC is a transcription factor that is involved in the expression of many genes. Deregulated MYC is found in about half of human tumors, being more prevalent in hematological neoplasms. Deregulation mechanisms include chromosomal translocation (particularly in lymphoma, amplification, and hyperactivation of MYC transcription. Here we review MYC involvement in the major types of leukemia and lymphoma. MYC rearrangements appear in all Burkitt lymphomas and are common in other lymphoma types, whereas in acute lymphoblastic leukemia, acute myeloid leukemia, lymphoproliferative, and myeloproferative diseases, they are less frequent. However, MYC overexpression is present in all types of hematological malignancies and often correlates with a worse prognosis. Data in leukemia-derived cells and in animal models of lymphomagenesis and leukemogenesis suggest that MYC would be a good therapeutic target. Several MYC-directed therapies have been assayed in preclinical settings and even in clinical trials. First, peptides and small molecules that interrupt the MYC–MAX interaction impair MYC-mediated tumorogenesis in several mouse models of solid tumors, although not yet in lymphoma and leukemia models. Second, there are a number of small molecules inhibiting the interaction of MYC–MAX heterodimers with DNA, still in the preclinical research phase. Third, inhibitors of MYC expression via the inhibition of BRD4 (a reader of acetylated histones have been shown to control the growth of MYC-transformed leukemia and lymphoma cells and are being used in clinic trials. Finally, we review a number of promising MYC

  6. Lack of induction of tissue transglutaminase but activation of the preexisting enzyme in c-Myc-induced apoptosis of CHO cells.

    Science.gov (United States)

    Balajthy, Z; Kedei, N; Nagy, L; Davies, P J; Fésüs, L

    1997-07-18

    The intracellular activity and expression of tissue transglutaminase, which crosslinks proteins through epsilon(gamma-glutamyl)lysine isodipeptide bond, was investigated in CHO cells and those stably transfected with either inducible c-Myc (which leads to apoptosis) or with c-myc and the apoptosis inhibitor Bcl-2. Protein-bound cross-link content was significantly higher when apoptosis was induced by c-Myc while the concomitant presence of Bcl-2 markedly reduced both apoptosis and enzymatic protein cross-linking. The expression of tissue transglutaminase did not change following the initiation of apoptosis by c-Myc or when it was blocked by Bcl-2. Studying transiently co-transfected elements of the mouse tissue transglutaminase promoter linked to a reporter enzyme revealed their overall repression in cells expressing c-Myc. This repression was partially suspended in cells also carrying Bcl-2. Our data suggest that tissue transglutaminase is not induced when c-Myc initiates apoptosis but the pre-existing endogenous enzyme is activated.

  7. Transcriptional Dysregulation of MYC Reveals Common Enhancer-Docking Mechanism

    Directory of Open Access Journals (Sweden)

    Jurian Schuijers

    2018-04-01

    Full Text Available Summary: Transcriptional dysregulation of the MYC oncogene is among the most frequent events in aggressive tumor cells, and this is generally accomplished by acquisition of a super-enhancer somewhere within the 2.8 Mb TAD where MYC resides. We find that these diverse cancer-specific super-enhancers, differing in size and location, interact with the MYC gene through a common and conserved CTCF binding site located 2 kb upstream of the MYC promoter. Genetic perturbation of this enhancer-docking site in tumor cells reduces CTCF binding, super-enhancer interaction, MYC gene expression, and cell proliferation. CTCF binding is highly sensitive to DNA methylation, and this enhancer-docking site, which is hypomethylated in diverse cancers, can be inactivated through epigenetic editing with dCas9-DNMT. Similar enhancer-docking sites occur at other genes, including genes with prominent roles in multiple cancers, suggesting a mechanism by which tumor cell oncogenes can generally hijack enhancers. These results provide insights into mechanisms that allow a single target gene to be regulated by diverse enhancer elements in different cell types. : Schuijers et al. show that a conserved CTCF site at the promoter of the MYC oncogene plays an important role in enhancer-promoter looping with tumor-specific super-enhancers. Perturbation of this site provides a potential therapeutic vulnerability. Keywords: gene regulation, super-enhancers, chromosome structure, enhancer docking

  8. Identification and Regulation of c-Myb Target Genes in MCF-7 Cells

    Directory of Open Access Journals (Sweden)

    O'Rourke John P

    2011-01-01

    Full Text Available Abstract Background The c-Myb transcription factor regulates differentiation and proliferation in hematopoietic cells, stem cells and epithelial cells. Although oncogenic versions of c-Myb were first associated with leukemias, over expression or rearrangement of the c-myb gene is common in several types of solid tumors, including breast cancers. Expression of the c-myb gene in human breast cancer cells is dependent on estrogen stimulation, but little is known about the activities of the c-Myb protein or what genes it regulates in estrogen-stimulated cells. Methods We used chromatin immunoprecipitation coupled with whole genome promoter tiling microarrays to identify endogenous c-Myb target genes in human MCF-7 breast cancer cells and characterized the activity of c-Myb at a panel of target genes during different stages of estrogen deprivation and stimulation. Results By using different antibodies and different growth conditions, the c-Myb protein was found associated with over 10,000 promoters in MCF-7 cells, including many genes that encode cell cycle regulators or transcription factors and more than 60 genes that encode microRNAs. Several previously identified c-Myb target genes were identified, including CCNB1, MYC and CXCR4 and novel targets such as JUN, KLF4, NANOG and SND1. By studying a panel of these targets to validate the results, we found that estradiol stimulation triggered the association of c-Myb with promoters and that association correlated with increased target gene expression. We studied one target gene, CXCR4, in detail, showing that c-Myb associated with the CXCR4 gene promoter and activated a CXCR4 reporter gene in transfection assays. Conclusions Our results show that c-Myb associates with a surprisingly large number of promoters in human cells. The results also suggest that estradiol stimulation leads to large-scale, genome-wide changes in c-Myb activity and subsequent changes in gene expression in human breast cancer

  9. Identification and Regulation of c-Myb Target Genes in MCF-7 Cells

    International Nuclear Information System (INIS)

    Quintana, Anita M; Liu, Fan; O'Rourke, John P; Ness, Scott A

    2011-01-01

    The c-Myb transcription factor regulates differentiation and proliferation in hematopoietic cells, stem cells and epithelial cells. Although oncogenic versions of c-Myb were first associated with leukemias, over expression or rearrangement of the c-myb gene is common in several types of solid tumors, including breast cancers. Expression of the c-myb gene in human breast cancer cells is dependent on estrogen stimulation, but little is known about the activities of the c-Myb protein or what genes it regulates in estrogen-stimulated cells. We used chromatin immunoprecipitation coupled with whole genome promoter tiling microarrays to identify endogenous c-Myb target genes in human MCF-7 breast cancer cells and characterized the activity of c-Myb at a panel of target genes during different stages of estrogen deprivation and stimulation. By using different antibodies and different growth conditions, the c-Myb protein was found associated with over 10,000 promoters in MCF-7 cells, including many genes that encode cell cycle regulators or transcription factors and more than 60 genes that encode microRNAs. Several previously identified c-Myb target genes were identified, including CCNB1, MYC and CXCR4 and novel targets such as JUN, KLF4, NANOG and SND1. By studying a panel of these targets to validate the results, we found that estradiol stimulation triggered the association of c-Myb with promoters and that association correlated with increased target gene expression. We studied one target gene, CXCR4, in detail, showing that c-Myb associated with the CXCR4 gene promoter and activated a CXCR4 reporter gene in transfection assays. Our results show that c-Myb associates with a surprisingly large number of promoters in human cells. The results also suggest that estradiol stimulation leads to large-scale, genome-wide changes in c-Myb activity and subsequent changes in gene expression in human breast cancer cells

  10. Piperlongumine inhibits LMP1/MYC-dependent mouse B-lymphoma cells

    International Nuclear Information System (INIS)

    Han, Seong-Su; Tompkins, Van S.; Son, Dong-Ju; Kamberos, Natalie L.; Stunz, Laura L.; Halwani, Ahmad; Bishop, Gail A.; Janz, Siegfried

    2013-01-01

    Highlights: •Mouse model of human Burkitt lymphoma revealed cancer inhibition by PL. •Treatment with PL led to apoptosis of malignant but not normal B cells. •PL inhibited LMP1–NF-κB–Myc-dependent target genes including p21-encoding Cdkn1a. •PL holds promise for new interventions approaches to hematologic malignancies. -- Abstract: Piperlongumine (PL), isolated from the fruit of Long pepper, Piper longum, is a cancer-inhibiting compound that selectively kills tumor cells while sparing their normal counterparts. Here we evaluated the efficacy with which PL suppresses malignant B cells derived from a newly developed, double-transgenic mouse model of human endemic Burkitt lymphoma (BL), designated mCD40-LMP1/iMyc Eμ . PL inhibited tumor cell proliferation in a concentration-dependent manner and induced apoptosis of neoplastic but not normal B cells. Treatment with PL resulted in downregulation of EBV-encoded LMP1, cellular Myc, constitutive NF-κB activity, and a host of LMP1-Myc-NF-κB-regulated target genes including Aurka, Bcat1, Bub1b, Ccnb1, Chek1, Fancd2, Tfrc and Xrcc6. Of note, p21 Cip1 -encoding Cdkn1a was suppressed independent of changes in Trp53 mRNA levels and p53 DNA-binding activity. Considering the central role of the LMP1–NF-κB–Myc axis in B-lineage neoplasia, these findings further our understanding of the mechanisms by which PL inhibits B-lymphoma and provide a preclinical rationale for the inclusion of PL in new interventions in blood cancers

  11. Piperlongumine inhibits LMP1/MYC-dependent mouse B-lymphoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Han, Seong-Su; Tompkins, Van S. [Department of Pathology, University of Iowa Carver College of Medicine, Iowa City, IA (United States); Son, Dong-Ju [Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA (United States); Kamberos, Natalie L. [Department of Pediatrics, University of Iowa Carver College of Medicine, Iowa City, IA (United States); Stunz, Laura L. [Deparment of Microbiology, University of Iowa Carver College of Medicine, Iowa City, IA (United States); Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA (United States); Iowa City VAMC, Iowa City, IA (United States); Halwani, Ahmad [Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA (United States); Bishop, Gail A. [Deparment of Microbiology, University of Iowa Carver College of Medicine, Iowa City, IA (United States); Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA (United States); Iowa City VAMC, Iowa City, IA (United States); Janz, Siegfried, E-mail: siegfried-janz@uiowa.edu [Department of Pathology, University of Iowa Carver College of Medicine, Iowa City, IA (United States)

    2013-07-12

    Highlights: •Mouse model of human Burkitt lymphoma revealed cancer inhibition by PL. •Treatment with PL led to apoptosis of malignant but not normal B cells. •PL inhibited LMP1–NF-κB–Myc-dependent target genes including p21-encoding Cdkn1a. •PL holds promise for new interventions approaches to hematologic malignancies. -- Abstract: Piperlongumine (PL), isolated from the fruit of Long pepper, Piper longum, is a cancer-inhibiting compound that selectively kills tumor cells while sparing their normal counterparts. Here we evaluated the efficacy with which PL suppresses malignant B cells derived from a newly developed, double-transgenic mouse model of human endemic Burkitt lymphoma (BL), designated mCD40-LMP1/iMyc{sup Eμ}. PL inhibited tumor cell proliferation in a concentration-dependent manner and induced apoptosis of neoplastic but not normal B cells. Treatment with PL resulted in downregulation of EBV-encoded LMP1, cellular Myc, constitutive NF-κB activity, and a host of LMP1-Myc-NF-κB-regulated target genes including Aurka, Bcat1, Bub1b, Ccnb1, Chek1, Fancd2, Tfrc and Xrcc6. Of note, p21{sup Cip1}-encoding Cdkn1a was suppressed independent of changes in Trp53 mRNA levels and p53 DNA-binding activity. Considering the central role of the LMP1–NF-κB–Myc axis in B-lineage neoplasia, these findings further our understanding of the mechanisms by which PL inhibits B-lymphoma and provide a preclinical rationale for the inclusion of PL in new interventions in blood cancers.

  12. c-Myc Represses Transcription of Epstein-Barr Virus Latent Membrane Protein 1 Early after Primary B Cell Infection.

    Science.gov (United States)

    Price, Alexander M; Messinger, Joshua E; Luftig, Micah A

    2018-01-15

    Recent evidence has shown that the Epstein-Barr virus (EBV) oncogene LMP1 is not expressed at high levels early after EBV infection of primary B cells, despite its being essential for the long-term outgrowth of immortalized lymphoblastoid cell lines (LCLs). In this study, we found that expression of LMP1 increased 50-fold between 7 days postinfection and the LCL state. Metabolic labeling of nascent transcribed mRNA indicated that this was primarily a transcription-mediated event. EBNA2, the key viral transcription factor regulating LMP1, and CTCF, an important chromatin insulator, were recruited to the LMP1 locus similarly early and late after infection. However, the activating histone H3K9Ac mark was enriched at the LMP1 promoter in LCLs relative to that in infected B cells early after infection. We found that high c-Myc activity in EBV-infected lymphoma cells as well as overexpression of c-Myc in an LCL model system repressed LMP1 transcription. Finally, we found that chemical inhibition of c-Myc both in LCLs and early after primary B cell infection increased LMP1 expression. These data support a model in which high levels of endogenous c-Myc activity induced early after primary B cell infection directly repress LMP1 transcription. IMPORTANCE EBV is a highly successful pathogen that latently infects more than 90% of adults worldwide and is also causally associated with a number of B cell malignancies. During the latent life cycle, EBV expresses a set of viral oncoproteins and noncoding RNAs with the potential to promote cancer. Critical among these is the viral latent membrane protein LMP1. Prior work suggests that LMP1 is essential for EBV to immortalize B cells, but our recent work indicates that LMP1 is not produced at high levels during the first few weeks after infection. Here we show that transcription of the LMP1 gene can be negatively regulated by a host transcription factor, c-Myc. Ultimately, understanding the regulation of EBV oncogenes will allow us

  13. Nac1 promotes self-renewal of embryonic stem cells through direct transcriptional regulation of c-Myc.

    Science.gov (United States)

    Ruan, Yan; He, Jianrong; Wu, Wei; He, Ping; Tian, Yanping; Xiao, Lan; Liu, Gaoke; Wang, Jiali; Cheng, Yuda; Zhang, Shuo; Yang, Yi; Xiong, Jiaxiang; Zhao, Ke; Wan, Ying; Huang, He; Zhang, Junlei; Jian, Rui

    2017-07-18

    The pluripotency transcriptional network in embryonic stem cells (ESCs) is composed of distinct functional units including the core and Myc units. It is hoped that dissection of the cellular functions and interconnections of network factors will aid our understanding of ESC and cancer biology. Proteomic and genomic approaches have identified Nac1 as a member of the core pluripotency network. However, previous studies have predominantly focused on the role of Nac1 in psychomotor stimulant response and cancer pathogenesis. In this study, we report that Nac1 is a self-renewal promoting factor, but is not required for maintaining pluripotency of ESCs. Loss of function of Nac1 in ESCs results in a reduced proliferation rate and an enhanced differentiation propensity. Nac1 overexpression promotes ESC proliferation and delays ESC differentiation in the absence of leukemia inhibitory factor (LIF). Furthermore, we demonstrated that Nac1 directly binds to the c-Myc promoter and regulates c-Myc transcription. The study also revealed that the function of Nac1 in promoting ESC self-renewal appears to be partially mediated by c-Myc. These findings establish a functional link between the core and c-Myc-centered networks and provide new insights into mechanisms of stemness regulation in ESCs and cancer.

  14. Using a Novel Transgenic Mouse Model to Study c-Myc Oncogenic Pathway in Castration Resistance and Chemoresistance of Prostate Cancer

    Science.gov (United States)

    2017-12-01

    AWARD NUMBER: W81XWH-13-1-0162 TITLE: Using a Novel Transgenic Mouse Model to Study c -Myc Oncogenic Pathway in Castration Resistance and...DATES COVERED 15Sept2013 - 14Sept2017 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Using a Novel Transgenic Mouse Model to Study c -Myc Oncogenic...ABSTRACT We previously made a PB-Cre4/Ai-Myc model for Cre-induced and androgen-independent expression of c -Myc and Luc2 in prostate. This is designed

  15. The long non-coding RNA GAS5 cooperates with the eukaryotic translation initiation factor 4E to regulate c-Myc translation.

    Directory of Open Access Journals (Sweden)

    Guangzhen Hu

    Full Text Available Long noncoding RNAs (lncRNAs are important regulators of transcription; however, their involvement in protein translation is not well known. Here we explored whether the lncRNA GAS5 is associated with translation initiation machinery and regulates translation. GAS5 was enriched with eukaryotic translation initiation factor-4E (eIF4E in an RNA-immunoprecipitation assay using lymphoma cell lines. We identified two RNA binding motifs within eIF4E protein and the deletion of each motif inhibited the binding of GAS5 with eIF4E. To confirm the role of GAS5 in translation regulation, GAS5 siRNA and in vitro transcribed GAS5 RNA were used to knock down or overexpress GAS5, respectively. GAS5 siRNA had no effect on global protein translation but did specifically increase c-Myc protein level without an effect on c-Myc mRNA. The mechanism of this increase in c-Myc protein was enhanced association of c-Myc mRNA with the polysome without any effect on protein stability. In contrast, overexpression of in vitro transcribed GAS5 RNA suppressed c-Myc protein without affecting c-Myc mRNA. Interestingly, GAS5 was found to be bound with c-Myc mRNA, suggesting that GAS5 regulates c-Myc translation through lncRNA-mRNA interaction. Our findings have uncovered a role of GAS5 lncRNA in translation regulation through its interactions with eIF4E and c-Myc mRNA.

  16. Transcriptional Dysregulation of MYC Reveals Common Enhancer-Docking Mechanism.

    Science.gov (United States)

    Schuijers, Jurian; Manteiga, John Colonnese; Weintraub, Abraham Selby; Day, Daniel Sindt; Zamudio, Alicia Viridiana; Hnisz, Denes; Lee, Tong Ihn; Young, Richard Allen

    2018-04-10

    Transcriptional dysregulation of the MYC oncogene is among the most frequent events in aggressive tumor cells, and this is generally accomplished by acquisition of a super-enhancer somewhere within the 2.8 Mb TAD where MYC resides. We find that these diverse cancer-specific super-enhancers, differing in size and location, interact with the MYC gene through a common and conserved CTCF binding site located 2 kb upstream of the MYC promoter. Genetic perturbation of this enhancer-docking site in tumor cells reduces CTCF binding, super-enhancer interaction, MYC gene expression, and cell proliferation. CTCF binding is highly sensitive to DNA methylation, and this enhancer-docking site, which is hypomethylated in diverse cancers, can be inactivated through epigenetic editing with dCas9-DNMT. Similar enhancer-docking sites occur at other genes, including genes with prominent roles in multiple cancers, suggesting a mechanism by which tumor cell oncogenes can generally hijack enhancers. These results provide insights into mechanisms that allow a single target gene to be regulated by diverse enhancer elements in different cell types. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

  17. EFFECT OF STENT ABSORBED c-myc ANTISENSE OLIGODEOXYNUCLEOTIDE ON SMOOTH MUSCLE CELLS APOPTOSIS IN RABBIT CAROTID ARTERY

    Institute of Scientific and Technical Information of China (English)

    张新霞; 崔长琮; 李江; 崔翰斌; 徐仓宝; 朱参战

    2002-01-01

    Objective To investigate the effect of gelatin coated Platinium-Iridium stent absorbed c-myc antisense oligodeoxynucleotide (ASODN) on smooth muscle cells apoptosis in a normal rabbit carotid arteries. Methods Gelatin coated Platinium-Iridium stents were implanted in the right carotid arteries of 32 rabbits under vision. Animals were randomly divided into control group and treated group receiving c-myc ASODN (n=16, respectively). On 7, 14, 30 and 90 days following the stenting procedure ,morphometry for caculation of neointimal area and mean neointimal thickness were performed.The expression of c-myc protein was detected by immunohistochemical method. Apoptotic smooth muscle cells was detected by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL). Results At 7 and 14 days after stenting,there were no detectable apoptotic cells in both groups. The apoptotic cells occurred in the neointima 30 and 90 days after stenting, and the number of apoptotic cells at 30 days were less [4.50±1.29 vs 25.75±1.89 (number/0.1mm2)] than that at 90 days [13.50±1.91 vs 41.50±6.46 (number/0.1mm2)]. Meanwhile c-myc ASODN induced more apoptotic cells than the control group(P<0.0001). c-myc protein expression was weak positive or negative in treated group and positive in control group.Conclusion c-myc ASODN can induce smooth muscle cells apoptosis after stenting in normal rabbit carotid arteries,and it can be used to prevent in-stent restenosis.

  18. MYC Targeted Long Noncoding RNA DANCR Promotes Cancer in Part by Reducing p21 Levels.

    Science.gov (United States)

    Lu, Yunqi; Hu, Zhongyi; Mangala, Lingegowda S; Stine, Zachary E; Hu, Xiaowen; Jiang, Dahai; Xiang, Yan; Zhang, Youyou; Pradeep, Sunila; Rodriguez-Aguayo, Cristian; Lopez-Berestein, Gabriel; DeMarzo, Angelo M; Sood, Anil K; Zhang, Lin; Dang, Chi V

    2018-01-01

    The MYC oncogene broadly promotes transcription mediated by all nuclear RNA polymerases, thereby acting as a positive modifier of global gene expression. Here, we report that MYC stimulates the transcription of DANCR, a long noncoding RNA (lncRNA) that is widely overexpressed in human cancer. We identified DANCR through its overexpression in a transgenic model of MYC-induced lymphoma, but found that it was broadly upregulated in many human cancer cell lines and cancers, including most notably in prostate and ovarian cancers. Mechanistic investigations indicated that DANCR limited the expression of cell-cycle inhibitor p21 (CDKN1A) and that the inhibitory effects of DANCR loss on cell proliferation could be partially rescued by p21 silencing. In a xenograft model of human ovarian cancer, a nanoparticle-mediated siRNA strategy to target DANCR in vivo was sufficient to strongly inhibit tumor growth. Our observations expand knowledge of how MYC drives cancer cell proliferation by identifying DANCR as a critical lncRNA widely overexpressed in human cancers. Significance: These findings expand knowledge of how MYC drives cancer cell proliferation by identifying an oncogenic long noncoding RNA that is widely overexpressed in human cancers. Cancer Res; 78(1); 64-74. ©2017 AACR . ©2017 American Association for Cancer Research.

  19. Protein kinase A antagonist inhibits β-catenin nuclear translocation, c-Myc and COX-2 expression and tumor promotion in ApcMin/+ mice

    Directory of Open Access Journals (Sweden)

    Brudvik Kristoffer W

    2011-12-01

    Full Text Available Abstract Background The adenomatous polyposis coli (APC protein is part of the destruction complex controlling proteosomal degradation of β-catenin and limiting its nuclear translocation, which is thought to play a gate-keeping role in colorectal cancer. The destruction complex is inhibited by Wnt-Frz and prostaglandin E2 (PGE2 - PI-3 kinase pathways. Recent reports show that PGE2-induced phosphorylation of β-catenin by protein kinase A (PKA increases nuclear translocation indicating two mechanisms of action of PGE2 on β-catenin homeostasis. Findings Treatment of ApcMin/+ mice that spontaneously develop intestinal adenomas with a PKA antagonist (Rp-8-Br-cAMPS selectively targeting only the latter pathway reduced tumor load, but not the number of adenomas. Immunohistochemical characterization of intestines from treated and control animals revealed that expression of β-catenin, β-catenin nuclear translocation and expression of the β-catenin target genes c-Myc and COX-2 were significantly down-regulated upon Rp-8-Br-cAMPS treatment. Parallel experiments in a human colon cancer cell line (HCT116 revealed that Rp-8-Br-cAMPS blocked PGE2-induced β-catenin phosphorylation and c-Myc upregulation. Conclusion Based on our findings we suggest that PGE2 act through PKA to promote β-catenin nuclear translocation and tumor development in ApcMin/+ mice in vivo, indicating that the direct regulatory effect of PKA on β-catenin nuclear translocation is operative in intestinal cancer.

  20. Key Roles for MYC, KIT and RET signaling in secondary angiosarcomas

    DEFF Research Database (Denmark)

    Styring, E; Seinen, J; Dominguez-Valentin, M

    2014-01-01

    of the gene signature to an external data set. RESULTS: In total, 103 genes were significantly deregulated between primary and secondary angiosarcomas. Secondary angiosarcomas showed upregulation of MYC, KIT and RET and downregulation of CDKN2C. Functional annotation analysis identified multiple target genes...... in the receptor protein tyrosine kinase pathway. The results were validated using RT-qPCR and immunohistochemistry. Further, the gene signature was applied to an external data set and, herein, distinguished primary from secondary angiosarcomas. CONCLUSIONS: Upregulation of MYC, KIT and RET and downregulation......BACKGROUND: Angiosarcomas may develop as primary tumours of unknown cause or as secondary tumours, most commonly following radiotherapy to the involved field. The different causative agents may be linked to alternate tumorigenesis, which led us to investigate the genetic profiles of morphologically...

  1. Clinical features, tumor biology, and prognosis associated with MYC rearrangement and Myc overexpression in diffuse large B-cell lymphoma patients treated with rituximab-CHOP

    DEFF Research Database (Denmark)

    Xu-Monette, Zijun Y; Dabaja, Bouthaina S; Wang, Xiaoxiao

    2015-01-01

    MYC dysregulation, including MYC gene rearrangement and Myc protein overexpression, is of increasing clinical importance in diffuse large B-cell lymphoma (DLBCL). However, the roles of MYC and the relative importance of rearrangement vs overexpression remain to be refined. Gaining knowledge about...

  2. GCN5 Regulates FGF Signaling and Activates Selective MYC Target Genes during Early Embryoid Body Differentiation

    Directory of Open Access Journals (Sweden)

    Li Wang

    2018-01-01

    Full Text Available Precise control of gene expression during development is orchestrated by transcription factors and co-regulators including chromatin modifiers. How particular chromatin-modifying enzymes affect specific developmental processes is not well defined. Here, we report that GCN5, a histone acetyltransferase essential for embryonic development, is required for proper expression of multiple genes encoding components of the fibroblast growth factor (FGF signaling pathway in early embryoid bodies (EBs. Gcn5−/− EBs display deficient activation of ERK and p38, mislocalization of cytoskeletal components, and compromised capacity to differentiate toward mesodermal lineage. Genomic analyses identified seven genes as putative direct targets of GCN5 during early differentiation, four of which are cMYC targets. These findings established a link between GCN5 and the FGF signaling pathway and highlighted specific GCN5-MYC partnerships in gene regulation during early differentiation.

  3. c-Myc Represses Tumor-Suppressive microRNAs, let-7a, miR-16 and miR-29b, and Induces Cyclin D2-Mediated Cell Proliferation in Ewing's Sarcoma Cell Line.

    Directory of Open Access Journals (Sweden)

    Masanori Kawano

    Full Text Available Myc oncogenic transcription factor is known to inhibit tumor suppressive microRNAs (miRNAs, resulting in greater expression of their target protein related to cell cycle, invasion or anti-apoptotic factors in human cancer cells. To explore possible oncogenic factors in Ewing's sarcoma (ES, we conducted microarray-based approach to profile the changes in the expression of miRNAs and its downstream mRNAs in five ES cell lines and human mesenchymal stem cells (hMSCs. Three miRNAs, let-7a, miR-16 and miR-29b were significantly down-regulated, whereas c-Myc and cyclin D2 (CCND2 were significantly up-regulated in all tested ES cells compared with hMSCs. To verify that let-7a, miR-16 and miR-29b were the targets of c-Myc in ES cell lines, we transfected siRNA against c-Myc and confirmed the coordinate up-regulation of let-7a, miR-16 and miR-29b through the repression of c-Myc. The ES cells transfected with c-Myc-siRNA and let-7a, miR-16 and miR-29b exhibited the inhibition of the cell cycle progression. The increased expression of let-7a, miR-16 and miR-29b resulted in the reduction of CCND2 protein expression. We also demonstrated that c-Myc-siRNA treatment of ES cells was associated with the decreased expression of CCND2 as a down-stream of three miRNAs. Furthermore, the introduction of let-7a, miR-16 and miR-29b in ES cells could inhibit the c-Myc-mediated up-regulation of CCND2 resulted in the prevention of cell cycle progression. In addition, the transfection of let-7a, miR-16 and miR-29b in ES cells suppressed tumor growth ex vivo treatment. These findings suggests that the up-regulation of c-Myc inhibited the expression of let-7a, miR-16 and miR-29b subsequently induced CCND2 expression in ES cells. The present study might identify a novel oncogenic axis that c-Myc regulates the expression of CCND2 via let-7a, miR-16 and miR-29b, leading to the development new therapeutic targets for ES.

  4. Expression profile of the N-myc Downstream Regulated Gene 2 (NDRG2 in human cancers with focus on breast cancer

    Directory of Open Access Journals (Sweden)

    Vogel Lotte K

    2011-01-01

    Full Text Available Abstract Background Several studies have shown that NDRG2 mRNA is down-regulated or undetectable in various human cancers and cancer cell-lines. Although the function of NDRG2 is currently unknown, high NDRG2 expression correlates with improved prognosis in high-grade gliomas, gastric cancer and hepatocellular carcinomas. Furthermore, in vitro studies have revealed that over-expression of NDRG2 in cell-lines causes a significant reduction in their growth. The aim of this study was to examine levels of NDRG2 mRNA in several human cancers, with focus on breast cancer, by examining affected and normal tissue. Methods By labelling a human Cancer Profiling Array with a radioactive probe against NDRG2, we evaluated the level of NDRG2 mRNA in 154 paired normal and tumor samples encompassing 19 different human cancers. Furthermore, we used quantitative real-time RT-PCR to quantify the levels of NDRG2 and MYC mRNA in thyroid gland cancer and breast cancer, using a distinct set of normal and tumor samples. Results From the Cancer Profiling Array, we saw that the level of NDRG2 mRNA was reduced by at least 2-fold in almost a third of the tumor samples, compared to the normal counterpart, and we observed a marked decreased level in colon, cervix, thyroid gland and testis. However, a Benjamini-Hochberg correction showed that none of the tissues showed a significant reduction in NDRG2 mRNA expression in tumor tissue compared to normal tissue. Using quantitative RT-PCR, we observed a significant reduction in the level of NDRG2 mRNA in a distinct set of tumor samples from both thyroid gland cancer (p = 0.02 and breast cancer (p = 0.004, compared with normal tissue. MYC mRNA was not significantly altered in breast cancer or in thyroid gland cancer, compared with normal tissue. In thyroid gland, no correlation was found between MYC and NDRG2 mRNA levels, but in breast tissue we found a weakly significant correlation with a positive r-value in both normal and

  5. Expression profile of the N-myc Downstream Regulated Gene 2 (NDRG2) in human cancers with focus on breast cancer

    International Nuclear Information System (INIS)

    Lorentzen, Anders; Lewinsky, Rikke H; Bornholdt, Jette; Vogel, Lotte K; Mitchelmore, Cathy

    2011-01-01

    Several studies have shown that NDRG2 mRNA is down-regulated or undetectable in various human cancers and cancer cell-lines. Although the function of NDRG2 is currently unknown, high NDRG2 expression correlates with improved prognosis in high-grade gliomas, gastric cancer and hepatocellular carcinomas. Furthermore, in vitro studies have revealed that over-expression of NDRG2 in cell-lines causes a significant reduction in their growth. The aim of this study was to examine levels of NDRG2 mRNA in several human cancers, with focus on breast cancer, by examining affected and normal tissue. By labelling a human Cancer Profiling Array with a radioactive probe against NDRG2, we evaluated the level of NDRG2 mRNA in 154 paired normal and tumor samples encompassing 19 different human cancers. Furthermore, we used quantitative real-time RT-PCR to quantify the levels of NDRG2 and MYC mRNA in thyroid gland cancer and breast cancer, using a distinct set of normal and tumor samples. From the Cancer Profiling Array, we saw that the level of NDRG2 mRNA was reduced by at least 2-fold in almost a third of the tumor samples, compared to the normal counterpart, and we observed a marked decreased level in colon, cervix, thyroid gland and testis. However, a Benjamini-Hochberg correction showed that none of the tissues showed a significant reduction in NDRG2 mRNA expression in tumor tissue compared to normal tissue. Using quantitative RT-PCR, we observed a significant reduction in the level of NDRG2 mRNA in a distinct set of tumor samples from both thyroid gland cancer (p = 0.02) and breast cancer (p = 0.004), compared with normal tissue. MYC mRNA was not significantly altered in breast cancer or in thyroid gland cancer, compared with normal tissue. In thyroid gland, no correlation was found between MYC and NDRG2 mRNA levels, but in breast tissue we found a weakly significant correlation with a positive r-value in both normal and tumor tissues, suggesting that MYC and NDRG2 mRNA are

  6. Absence of DNA damage after 60-Hz electromagnetic field exposure combined with ionizing radiation, hydrogen peroxide, or c-Myc overexpression.

    Science.gov (United States)

    Jin, Yeung Bae; Choi, Seo-Hyun; Lee, Jae Seon; Kim, Jae-Kyung; Lee, Ju-Woon; Hong, Seung-Cheol; Myung, Sung Ho; Lee, Yun-Sil

    2014-03-01

    The principal objective of this study was to assess the DNA damage in a normal cell line system after exposure to 60 Hz of extremely low frequency magnetic field (ELF-MF) and particularly in combination with various external factors, via comet assays. NIH3T3 mouse fibroblast cells, WI-38 human lung fibroblast cells, L132 human lung epithelial cells, and MCF10A human mammary gland epithelial cells were exposed for 4 or 16 h to a 60-Hz, 1 mT uniform magnetic field in the presence or absence of ionizing radiation (IR, 1 Gy), H(2)O(2) (50 μM), or c-Myc oncogenic activation. The results obtained showed no significant differences between the cells exposed to ELF-MF alone and the unexposed cells. Moreover, no synergistic or additive effects were observed after 4 or 16 h of pre-exposure to 1 mT ELF-MF or simultaneous exposure to ELF-MF combined with IR, H(2)O(2), or c-Myc activation.

  7. Endoglin inhibits ERK-induced c-Myc and cyclin D1 expression to impede endothelial cell proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Christopher C.; Bloodworth, Jeffrey C. [Division of Pharmacology, Columbus, OH 43210 (United States); Mythreye, Karthikeyan [Duke University, Department of Medicine, Durham, NC 27708 (United States); Lee, Nam Y., E-mail: lee.5064@osu.edu [Division of Pharmacology, Columbus, OH 43210 (United States); Davis Heart and Lung Research Institute, Columbus, OH 43210 (United States)

    2012-08-03

    Highlights: Black-Right-Pointing-Pointer Endoglin inhibits ERK activation in endothelial cells. Black-Right-Pointing-Pointer Endoglin is a regulator of c-Myc and cyclin D1 expression. Black-Right-Pointing-Pointer {beta}-arrestin2 interaction with endoglin is required for ERK/c-Myc repression. Black-Right-Pointing-Pointer Endoglin impedes cellular proliferation by targeting ERK-induced mitogenic signaling. -- Abstract: Endoglin is an endothelial-specific transforming growth factor beta (TGF-{beta}) co-receptor essential for angiogenesis and vascular remodeling. Endoglin regulates a wide range of cellular processes, including cell adhesion, migration, and proliferation, through TGF-{beta} signaling to canonical Smad and Smad-independent pathways. Despite its overall pro-angiogenic role in the vasculature, the underlying mechanism of endoglin action is poorly characterized. We previously identified {beta}-arrestin2 as a binding partner that causes endoglin internalization from the plasma membrane and inhibits ERK signaling towards endothelial migration. In the present study, we examined the mechanistic role of endoglin and {beta}-arrestin2 in endothelial cell proliferation. We show that endoglin impedes cell growth through sustained inhibition of ERK-induced c-Myc and cyclin D1 expression in a TGF-{beta}-independent manner. The down-regulation of c-Myc and cyclin D1, along with growth-inhibition, are reversed when the endoglin/{beta}-arrestin2 interaction is disrupted. Given that TGF-{beta}-induced Smad signaling potently represses c-Myc in most cell types, our findings here show a novel mechanism by which endoglin augments growth-inhibition by targeting ERK and key downstream mitogenic substrates.

  8. Targeting C-Myc Promoter: Helquats As Novel G-Quadruplex Stabilizing Ligands

    Czech Academy of Sciences Publication Activity Database

    Kužmová, Erika; Kozák, Jaroslav; Komárková, Veronika; Pytlík, R.; Teplý, Filip; Hájek, Miroslav

    2014-01-01

    Roč. 124, č. 21 (2014) ISSN 0006-4971. [Annual Meeting of the American Society of Hematology /56./. 06.12.2014-09.12.2014, San Francisco] Institutional support: RVO:61388963 Keywords : helquats * C-Myc * leukemia Subject RIV: CE - Biochemistry

  9. The TCA cycle transferase DLST is important for MYC-mediated leukemogenesis.

    Science.gov (United States)

    Anderson, N M; Li, D; Peng, H L; Laroche, F J F; Mansour, M R; Gjini, E; Aioub, M; Helman, D J; Roderick, J E; Cheng, T; Harrold, I; Samaha, Y; Meng, L; Amsterdam, A; Neuberg, D S; Denton, T T; Sanda, T; Kelliher, M A; Singh, A; Look, A T; Feng, H

    2016-06-01

    Despite the pivotal role of MYC in the pathogenesis of T-cell acute lymphoblastic leukemia (T-ALL) and many other cancers, the mechanisms underlying MYC-mediated tumorigenesis remain inadequately understood. Here we utilized a well-characterized zebrafish model of Myc-induced T-ALL for genetic studies to identify novel genes contributing to disease onset. We found that heterozygous inactivation of a tricarboxylic acid (TCA) cycle enzyme, dihydrolipoamide S-succinyltransferase (Dlst), significantly delayed tumor onset in zebrafish without detectable effects on fish development. DLST is the E2 transferase of the α-ketoglutarate (α-KG) dehydrogenase complex (KGDHC), which converts α-KG to succinyl-CoA in the TCA cycle. RNAi knockdown of DLST led to decreased cell viability and induction of apoptosis in human T-ALL cell lines. Polar metabolomics profiling revealed that the TCA cycle was disrupted by DLST knockdown in human T-ALL cells, as demonstrated by an accumulation of α-KG and a decrease of succinyl-CoA. Addition of succinate, the downstream TCA cycle intermediate, to human T-ALL cells was sufficient to rescue defects in cell viability caused by DLST inactivation. Together, our studies uncovered an important role for DLST in MYC-mediated leukemogenesis and demonstrated the metabolic dependence of T-lymphoblasts on the TCA cycle, thus providing implications for targeted therapy.

  10. Down-regulation of 5S rRNA by miR-150 and miR-383 enhances c-Myc-rpL11 interaction and inhibits proliferation of esophageal squamous carcinoma cells.

    Science.gov (United States)

    Wang, Xinyu; Ren, Yanli; Wang, Zhiqiong; Xiong, Xiangyu; Han, Sichong; Pan, Wenting; Chen, Hongwei; Zhou, Liqing; Zhou, Changchun; Yuan, Qipeng; Yang, Ming

    2015-12-21

    5S rRNA plays an important part in ribosome biology and is over-expression in multiple cancers. In this study, we found that 5S rRNA is a direct target of miR-150 and miR-383 in esophageal squamous cell carcinoma (ESCC). Overexpression of miR-150 and miR-383 inhibited ESCC cell proliferation in vitro and in vivo. Moreover, 5S rRNA silencing by miR-150 and miR-383 might intensify rpL11-c-Myc interaction, which attenuated role of c-Myc as an oncogenic transcriptional factor and dysregulation of multiple c-Myc target genes. Taken together, our results highlight the involvement of miRNAs in ribosomal regulation during tumorigenesis. Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  11. SLAM-seq defines direct gene-regulatory functions of the BRD4-MYC axis.

    Science.gov (United States)

    Muhar, Matthias; Ebert, Anja; Neumann, Tobias; Umkehrer, Christian; Jude, Julian; Wieshofer, Corinna; Rescheneder, Philipp; Lipp, Jesse J; Herzog, Veronika A; Reichholf, Brian; Cisneros, David A; Hoffmann, Thomas; Schlapansky, Moritz F; Bhat, Pooja; von Haeseler, Arndt; Köcher, Thomas; Obenauf, Anna C; Popow, Johannes; Ameres, Stefan L; Zuber, Johannes

    2018-05-18

    Defining direct targets of transcription factors and regulatory pathways is key to understanding their roles in physiology and disease. We combined SLAM-seq [thiol(SH)-linked alkylation for the metabolic sequencing of RNA], a method for direct quantification of newly synthesized messenger RNAs (mRNAs), with pharmacological and chemical-genetic perturbation in order to define regulatory functions of two transcriptional hubs in cancer, BRD4 and MYC, and to interrogate direct responses to BET bromodomain inhibitors (BETis). We found that BRD4 acts as general coactivator of RNA polymerase II-dependent transcription, which is broadly repressed upon high-dose BETi treatment. At doses triggering selective effects in leukemia, BETis deregulate a small set of hypersensitive targets including MYC. In contrast to BRD4, MYC primarily acts as a selective transcriptional activator controlling metabolic processes such as ribosome biogenesis and de novo purine synthesis. Our study establishes a simple and scalable strategy to identify direct transcriptional targets of any gene or pathway. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  12. Promoter trans-activation of protooncogenes c-fos and c-myc, but not c-Ha-ras, by products of adenovirus early region 1A

    International Nuclear Information System (INIS)

    Sassone-Corsi, P.; Borrelli, E.

    1987-01-01

    The E1A (early region 1A) oncogene products of adenovirus type 2 trans-activate the other early viral transcription units, as well as some cellular promoters. Using a short-term cotransfection assay in murine NIH 3T3 fibroblasts, we show that c-fos and c-myc promoter activities are stimulated by the E1A proteins, whereas c-Ha-ras transcription is not affected. The product of E1A 13S mRNA is responsible for the trans-activation, whereas the 12S mRNA product has no effect. Analysis of the c-fos promoter sequences required for the E1A stimulation shows that responsive sequences are located between positions -402 and -240 upstream of the transcription initiation site. This same region also contains the c-fos serum-responsive element. Furthermore, transcription of the endogenous c-fos gene in HeLa cells is increased after E1A transfection

  13. Involvement of SIRT1 in hypoxic down-regulation of c-Myc and β-catenin and hypoxic preconditioning effect of polyphenols

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Kyung-Soo [Department of Biochemistry, Pusan National University School of Medicine, Yangsan (Korea, Republic of); Research Center for Ischemic Tissue regeneration, Pusan National University School of Medicine, Yangsan (Korea, Republic of); Park, Jun-Ik [Department of Biochemistry, Pusan National University School of Medicine, Yangsan (Korea, Republic of); Kim, Mi-Ju; Kim, Hak-Bong; Lee, Jae-Won [Department of Biochemistry, Pusan National University School of Medicine, Yangsan (Korea, Republic of); Research Center for Ischemic Tissue regeneration, Pusan National University School of Medicine, Yangsan (Korea, Republic of); Dao, Trong Tuan; Oh, Won Keun [BK21 Project Team, College of Pharmacy, Chosun University, Gwangju (Korea, Republic of); Kang, Chi-Dug, E-mail: kcdshbw@pusan.ac.kr [Department of Biochemistry, Pusan National University School of Medicine, Yangsan (Korea, Republic of); Kim, Sun-Hee, E-mail: ksh7738@pusan.ac.kr [Department of Biochemistry, Pusan National University School of Medicine, Yangsan (Korea, Republic of); Research Center for Ischemic Tissue regeneration, Pusan National University School of Medicine, Yangsan (Korea, Republic of)

    2012-03-01

    SIRT1 has been found to function as a Class III deacetylase that affects the acetylation status of histones and other important cellular nonhistone proteins involved in various cellular pathways including stress responses and apoptosis. In this study, we investigated the role of SIRT1 signaling in the hypoxic down-regulations of c-Myc and β-catenin and hypoxic preconditioning effect of the red wine polyphenols such as piceatannol, myricetin, quercetin and resveratrol. We found that the expression of SIRT1 was significantly increased in hypoxia-exposed or hypoxic preconditioned HepG2 cells, which was closely associated with the up-regulation of HIF-1α and down-regulation of c-Myc and β-catenin expression via deacetylation of these proteins. In addition, blockade of SIRT1 activation using siRNA or amurensin G, a new potent SIRT1 inhibitor, abolished hypoxia-induced HIF-1α expression but increased c-Myc and β-catenin expression. SIRT1 was also found to stabilize HIF-1α protein and destabilize c-Myc, β-catenin and PHD2 under hypoxia. We also found that myricetin, quercetin, piceatannol and resveratrol up-regulated HIF-1α and down-regulated c-Myc, PHD2 and β-catenin expressions via SIRT1 activation, in a manner that mimics hypoxic preconditioning. This study provides new insights of the molecular mechanisms of hypoxic preconditioning and suggests that polyphenolic SIRT1 activators could be used to mimic hypoxic/ischemic preconditioning. -- Graphical abstract: Polyphenols mimicked hypoxic preconditioning by up-regulating HIF-1α and SIRT1 and down-regulating c-Myc, PHD2, and β-catenin. HepG2 cells were pretreated with the indicated doses of myricetin (MYR; A), quercetin (QUR; B), or piceatannol (PIC; C) for 4 h and then exposed to hypoxia for 4 h. Levels of HIF-1α, SIRT1, c-Myc, β-catenin, and PHD2 were determined by western blot analysis. The data are representative of three individual experiments. Highlights: ► SIRT1 expression is increased in hypoxia

  14. Involvement of SIRT1 in hypoxic down-regulation of c-Myc and β-catenin and hypoxic preconditioning effect of polyphenols

    International Nuclear Information System (INIS)

    Hong, Kyung-Soo; Park, Jun-Ik; Kim, Mi-Ju; Kim, Hak-Bong; Lee, Jae-Won; Dao, Trong Tuan; Oh, Won Keun; Kang, Chi-Dug; Kim, Sun-Hee

    2012-01-01

    SIRT1 has been found to function as a Class III deacetylase that affects the acetylation status of histones and other important cellular nonhistone proteins involved in various cellular pathways including stress responses and apoptosis. In this study, we investigated the role of SIRT1 signaling in the hypoxic down-regulations of c-Myc and β-catenin and hypoxic preconditioning effect of the red wine polyphenols such as piceatannol, myricetin, quercetin and resveratrol. We found that the expression of SIRT1 was significantly increased in hypoxia-exposed or hypoxic preconditioned HepG2 cells, which was closely associated with the up-regulation of HIF-1α and down-regulation of c-Myc and β-catenin expression via deacetylation of these proteins. In addition, blockade of SIRT1 activation using siRNA or amurensin G, a new potent SIRT1 inhibitor, abolished hypoxia-induced HIF-1α expression but increased c-Myc and β-catenin expression. SIRT1 was also found to stabilize HIF-1α protein and destabilize c-Myc, β-catenin and PHD2 under hypoxia. We also found that myricetin, quercetin, piceatannol and resveratrol up-regulated HIF-1α and down-regulated c-Myc, PHD2 and β-catenin expressions via SIRT1 activation, in a manner that mimics hypoxic preconditioning. This study provides new insights of the molecular mechanisms of hypoxic preconditioning and suggests that polyphenolic SIRT1 activators could be used to mimic hypoxic/ischemic preconditioning. -- Graphical abstract: Polyphenols mimicked hypoxic preconditioning by up-regulating HIF-1α and SIRT1 and down-regulating c-Myc, PHD2, and β-catenin. HepG2 cells were pretreated with the indicated doses of myricetin (MYR; A), quercetin (QUR; B), or piceatannol (PIC; C) for 4 h and then exposed to hypoxia for 4 h. Levels of HIF-1α, SIRT1, c-Myc, β-catenin, and PHD2 were determined by western blot analysis. The data are representative of three individual experiments. Highlights: ► SIRT1 expression is increased in hypoxia

  15. The human thyroglobulin gene: a polymorphic marker localized distal to C-MYC on chromosome 8 band q24

    NARCIS (Netherlands)

    Baas, F.; Bikker, H.; Geurts van Kessel, A.; Melsert, R.; Pearson, P. L.; de Vijlder, J. J.; van Ommen, G. J.

    1985-01-01

    The human thyroglobulin (Tg) gene is localized to chromosome 8 and regionally to band q24 as shown independently by both in situ hybridization techniques and Southern blot analysis of human-rodent somatic cell hybrids. Analysis of hybrids derived from a Burkitt lymphoma, with a translocation

  16. Myc and Fgf Are Required for Zebrafish Neuromast Hair Cell Regeneration.

    Science.gov (United States)

    Lee, Sang Goo; Huang, Mingqian; Obholzer, Nikolaus D; Sun, Shan; Li, Wenyan; Petrillo, Marco; Dai, Pu; Zhou, Yi; Cotanche, Douglas A; Megason, Sean G; Li, Huawei; Chen, Zheng-Yi

    2016-01-01

    Unlike mammals, the non-mammalian vertebrate inner ear can regenerate the sensory cells, hair cells, either spontaneously or through induction after hair cell loss, leading to hearing recovery. The mechanisms underlying the regeneration are poorly understood. By microarray analysis on a chick model, we show that chick hair cell regeneration involves the activation of proliferation genes and downregulation of differentiation genes. Both MYC and FGF are activated in chick hair cell regeneration. Using a zebrafish lateral line neuromast hair cell regeneration model, we show that the specific inhibition of Myc or Fgf suppresses hair cell regeneration, demonstrating that both pathways are essential to the process. Rapid upregulation of Myc and delayed Fgf activation during regeneration suggest a role of Myc in proliferation and Fgf in differentiation. The dorsal-ventral pattern of fgfr1a in the neuromasts overlaps with the distribution of hair cell precursors. By laser ablation, we show that the fgfr1a-positive supporting cells are likely the hair cell precursors that directly give rise to new hair cells; whereas the anterior-posterior fgfr1a-negative supporting cells have heightened proliferation capacity, likely to serve as more primitive progenitor cells to replenish lost precursors after hair cell loss. Thus fgfr1a is likely to mark compartmentalized supporting cell subtypes with different capacities in renewal proliferation and hair cell regeneration. Manipulation of c-MYC and FGF pathways could be explored for mammalian hair cell regeneration.

  17. In vivo distribution of c-myc antisense oligodeoxynucleotides local delivered by gelatin-coated platinmn-iridium stents in rabbits and its effect on apoptosis

    Institute of Scientific and Technical Information of China (English)

    张新霞; 崔长琮; 许香广; 胡雪松; 方卫华; 邝碧娟

    2004-01-01

    Background Post-stenting restenosis is a significant clinical problem, involving vascular smooth muscle cells(VSMCs) proliferation and apoptosis. It is reported that c-myc antisense oligodeoxynucleotides (ASODNs) local delivered by catheter can inhibit VSMCs proliferation. This study was designed to assess tissue distribution of c-myc ASODN local delivered using gelatin-coated platinum-iridium (Pt-Ir) stents, and its effect on apoptosis of VSMCs. Methods Gelatin-coated Pt-Ir stents that had absorbed caroboxyfluorescein-5-succimidyl ester (FAM) labeled c-myc ASODNs (550 μg per stent) were implanted into the right carotid arteries of 6 rabbits. Tissue samples were obtained at 45 minutes, 2 hours, and 6 hours. Tissue distribution of c- myc ASODNs was assessed by fluorescence microscopy. In addition, 32 rabbits were randomly divided into two groups. Rabbits in the control group (n=16) were implanted with gelatin-coated Pt-Ir stents, and those in the treatment group (n=16) were implanted with gelatin-coated stents that had absorbed c-myc ASODNs. 7, 14, 30, or 90 days (n=4, respectively, for each group) after the stenting procedure, the stented segments were harvested, and histopathological examinations were performed to calculate neointimal area and mean neointimal thickness. The expression of c-myc was assessed using in situ hybridization (ISH) and immunohistochemical methods. Apoptotic VSMCs were detected using terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) and transmission electron microscope (TEM). Results According to fluorescence microscopic results, FAM-labeled c-myc ASODNs were concentrated in the target vessel media at the 45 minutes time point, and then dispersed to the adventitia. Morphometric analysis showed that neointimal area and mean neointimal thickness increased continuously up to 90 days after stent implantation, but that total neointimal area and mean neointimal thickness were less in the treatment group than in the

  18. Novel Approach for Coexpression Analysis of E2F1–3 and MYC Target Genes in Chronic Myelogenous Leukemia

    Directory of Open Access Journals (Sweden)

    Fengfeng Wang

    2014-01-01

    Full Text Available Background. Chronic myelogenous leukemia (CML is characterized by tremendous amount of immature myeloid cells in the blood circulation. E2F1–3 and MYC are important transcription factors that form positive feedback loops by reciprocal regulation in their own transcription processes. Since genes regulated by E2F1–3 or MYC are related to cell proliferation and apoptosis, we wonder if there exists difference in the coexpression patterns of genes regulated concurrently by E2F1–3 and MYC between the normal and the CML states. Results. We proposed a method to explore the difference in the coexpression patterns of those candidate target genes between the normal and the CML groups. A disease-specific cutoff point for coexpression levels that classified the coexpressed gene pairs into strong and weak coexpression classes was identified. Our developed method effectively identified the coexpression pattern differences from the overall structure. Moreover, we found that genes related to the cell adhesion and angiogenesis properties were more likely to be coexpressed in the normal group when compared to the CML group. Conclusion. Our findings may be helpful in exploring the underlying mechanisms of CML and provide useful information in cancer treatment.

  19. MYC translocation-negative classical Burkitt lymphoma cases: an alternative pathogenetic mechanism involving miRNA deregulation

    DEFF Research Database (Denmark)

    Leucci, E; Cocco, M; Onnis, A

    2008-01-01

    at the standardization of FISH procedures in lymphoma diagnosis, we found that five cases out of 35 classic endemic BLs were negative for MYC translocations by using a split-signal as well as a dual-fusion probe. Here we investigated the expression pattern of miRNAs predicted to target c-Myc, in BL cases, to clarify...... whether alternative pathogenetic mechanisms may be responsible for lymphomagenesis in cases lacking the MYC translocation. miRNAs are a class of small RNAs that are able to regulate gene expression at the post-transcriptional level. Several studies have reported their involvement in cancer...

  20. Aspirin therapy reduces the ability of platelets to promote colon and pancreatic cancer cell proliferation: Implications for the oncoprotein c-MYC

    Science.gov (United States)

    Sylman, Joanna L.; Ngo, Anh T. P.; Pang, Jiaqing; Sears, Rosalie C.; Williams, Craig D.; McCarty, Owen J. T.

    2017-01-01

    Aspirin, an anti-inflammatory and antithrombotic drug, has become the focus of intense research as a potential anticancer agent owing to its ability to reduce tumor proliferation in vitro and to prevent tumorigenesis in patients. Studies have found an anticancer effect of aspirin when used in low, antiplatelet doses. However, the mechanisms through which low-dose aspirin works are poorly understood. In this study, we aimed to determine the effect of aspirin on the cross talk between platelets and cancer cells. For our study, we used two colon cancer cell lines isolated from the same donor but characterized by different metastatic potential, SW480 (nonmetastatic) and SW620 (metastatic) cancer cells, and a pancreatic cancer cell line, PANC-1 (nonmetastatic). We found that SW480 and PANC-1 cancer cell proliferation was potentiated by human platelets in a manner dependent on the upregulation and activation of the oncoprotein c-MYC. The ability of platelets to upregulate c-MYC and cancer cell proliferation was reversed by an antiplatelet concentration of aspirin. In conclusion, we show for the first time that inhibition of platelets by aspirin can affect their ability to induce cancer cell proliferation through the modulation of the c-MYC oncoprotein. PMID:27903583

  1. Targeting oncogenic Myc as a strategy for cancer treatment.

    Science.gov (United States)

    Chen, Hui; Liu, Hudan; Qing, Guoliang

    2018-01-01

    The MYC family oncogene is deregulated in >50% of human cancers, and this deregulation is frequently associated with poor prognosis and unfavorable patient survival. Myc has a central role in almost every aspect of the oncogenic process, orchestrating proliferation, apoptosis, differentiation, and metabolism. Although Myc inhibition would be a powerful approach for the treatment of many types of cancers, direct targeting of Myc has been a challenge for decades owing to its "undruggable" protein structure. Hence, alternatives to Myc blockade have been widely explored to achieve desirable anti-tumor effects, including Myc/Max complex disruption, MYC transcription and/or translation inhibition, and Myc destabilization as well as the synthetic lethality associated with Myc overexpression. In this review, we summarize the latest advances in targeting oncogenic Myc, particularly for cancer therapeutic purposes.

  2. Myeloblastic leukemia cells conditionally blocked by myc-estrogen receptor chimeric transgenes for terminal differentiation coupled to growth arrest and apoptosis.

    Science.gov (United States)

    Selvakumaran, M; Liebermann, D; Hoffman-Liebermann, B

    1993-05-01

    Conditional mutants of the myeloblastic leukemic M1 cell line, expressing the chimeric mycer transgene, have been established. It is shown that M1 mycer cells, like M1, undergo terminal differentiation coupled to growth arrest and programmed cell death (apoptosis) after treatment with the physiologic differentiation inducer interleukin-6. However, when beta-estradiol is included in the culture medium, M1 mycer cells respond to differentiation inducers like M1 myc cell lines, where the differentiation program is blocked at an intermediate stage. By manipulating the function of the mycer transgene product, it is shown that there is a 10-hour window during myeloid differentiation, from 30 to 40 hours after the addition of the differentiation inducer, when the terminal differentiation program switches from being dependent on c-myc suppression to becoming c-myc suppression independent, where activation of c-myc has no apparent effect on mature macrophages. M1 mycer cell lines provide a powerful tool to increase our understanding of the role of c-myc in normal myelopoiesis and in leukemogenesis, also providing a strategy to clone c-myc target genes.

  3. Lipopolysaccharide stimulates endogenous β-glucuronidase via PKC/NF-κB/c-myc signaling cascade: a possible factor in hepatolithiasis formation.

    Science.gov (United States)

    Yao, Dianbo; Dong, Qianze; Tian, Yu; Dai, Chaoliu; Wu, Shuodong

    2017-11-29

    Hepatolithiasis is commonly encountered in Southeastern and Eastern Asian countries, but the pathogenesis mechanism of stone formation is still not well understood. Now, the role of endogenous β-glucuronidase in pigment stones formation is being gradually recognized. In this study, the mechanism of increased expression and secretion of endogenous β-glucuronidase during hepatolithiasis formation was investigated. We assessed the endogenous β-glucuronidase, c-myc, p-p65, and p-PKC expression in liver specimens with hepatolithiasis by immunohistochemical staining, and found that compared with that in normal liver samples, the expression of endogenous β-glucuronidase, c-myc, p-p65, and p-PKC in liver specimens with hepatolithiasis significantly increased, and their expressions were positively correlated with each other. Lipopolysaccharide (LPS) induced increased expression of endogenous β-glucuronidase and c-myc in hepatocytes and intrahepatic biliary epithelial cells in a dose- and time-dependent manner, and endogenous β-glucuronidase secretion increased, correspondingly. C-myc siRNA transfection effectively inhibited the LPS-induced expression of endogenous β-glucuronidase. Furthermore, NF-κB inhibitor pyrrolidine dithiocarbamate or PKC inhibitor chelerythrine could effectively inhibit the LPS-induced expression of c-myc and endogenous β-glucuronidase, and the expression of p-p65 was also partly inhibited by chelerythrine. Our clinical observations and experimental data indicate that LPS could induce the increased expression and secretion of endogenous β-glucuronidase via a signaling cascade of PKC/NF-κB/c-myc in hepatocytes and intrahepatic biliary epithelial cells, and endogenous β-glucuronidase might play a possible role in the formation of hepatolithiasis.

  4. The interplay of long non-coding RNAs and MYC in cancer

    Directory of Open Access Journals (Sweden)

    Michael J. Hamilton

    2015-12-01

    Full Text Available Long non-coding RNAs (lncRNAs are a class of RNA molecules that are changing how researchers view eukaryotic gene regulation. Once considered to be non-functional products of low-level aberrant transcription from non-coding regions of the genome, lncRNAs are now viewed as important epigenetic regulators and several lncRNAs have now been demonstrated to be critical players in the development and/or maintenance of cancer. Similarly, the emerging variety of interactions between lncRNAs and MYC, a well-known oncogenic transcription factor linked to most types of cancer, have caught the attention of many biomedical researchers. Investigations exploring the dynamic interactions between lncRNAs and MYC, referred to as the lncRNA-MYC network, have proven to be especially complex. Genome-wide studies have shown that MYC transcriptionally regulates many lncRNA genes. Conversely, recent reports identified lncRNAs that regulate MYC expression both at the transcriptional and post-transcriptional levels. These findings are of particular interest because they suggest roles of lncRNAs as regulators of MYC oncogenic functions and the possibility that targeting lncRNAs could represent a novel avenue to cancer treatment. Here, we briefly review the current understanding of how lncRNAs regulate chromatin structure and gene transcription, and then focus on the new developments in the emerging field exploring the lncRNA-MYC network in cancer.

  5. A balance of Mad and Myc expression dictates larval cell apoptosis and adult stem cell development during Xenopus intestinal metamorphosis.

    Science.gov (United States)

    Okada, Morihiro; Miller, Thomas C; Wen, Luan; Shi, Yun-Bo

    2017-05-11

    The Myc/Mad/Max network has long been shown to be an important factor in regulating cell proliferation, death and differentiation in diverse cell types. In general, Myc-Max heterodimers activate target gene expression to promote cell proliferation, although excess of c-Myc can also induce apoptosis. In contrast, Mad competes against Myc to form Mad-Max heterodimers that bind to the same target genes to repress their expression and promote differentiation. The role of the Myc/Mad/Max network during vertebrate development, especially, the so-called postembryonic development, a period around birth in mammals, is unclear. Using thyroid hormone (T3)-dependent Xenopus metamorphosis as a model, we show here that Mad1 is induced by T3 in the intestine during metamorphosis when larval epithelial cell death and adult epithelial stem cell development take place. More importantly, we demonstrate that Mad1 is expressed in the larval cells undergoing apoptosis, whereas c-Myc is expressed in the proliferating adult stem cells during intestinal metamorphosis, suggesting that Mad1 may have a role in cell death during development. By using transcription activator-like effector nuclease-mediated gene-editing technology, we have generated Mad1 knockout Xenopus animals. This has revealed that Mad1 is not essential for embryogenesis or metamorphosis. On the other hand, consistent with its spatiotemporal expression profile, Mad1 knockout leads to reduced larval epithelial apoptosis but surprisingly also results in increased adult stem cell proliferation. These findings not only reveal a novel role of Mad1 in regulating developmental cell death but also suggest that a balance of Mad and Myc controls cell fate determination during adult organ development.

  6. Silencing c-Myc translation as a therapeutic strategy through targeting PI3Kδ and CK1ε in hematological malignancies.

    Science.gov (United States)

    Deng, Changchun; Lipstein, Mark R; Scotto, Luigi; Jirau Serrano, Xavier O; Mangone, Michael A; Li, Shirong; Vendome, Jeremie; Hao, Yun; Xu, Xiaoming; Deng, Shi-Xian; Realubit, Ronald B; Tatonetti, Nicholas P; Karan, Charles; Lentzsch, Suzanne; Fruman, David A; Honig, Barry; Landry, Donald W; O'Connor, Owen A

    2017-01-05

    Phosphoinositide 3-kinase (PI3K) and the proteasome pathway are both involved in activating the mechanistic target of rapamycin (mTOR). Because mTOR signaling is required for initiation of messenger RNA translation, we hypothesized that cotargeting the PI3K and proteasome pathways might synergistically inhibit translation of c-Myc. We found that a novel PI3K δ isoform inhibitor TGR-1202, but not the approved PI3Kδ inhibitor idelalisib, was highly synergistic with the proteasome inhibitor carfilzomib in lymphoma, leukemia, and myeloma cell lines and primary lymphoma and leukemia cells. TGR-1202 and carfilzomib (TC) synergistically inhibited phosphorylation of the eukaryotic translation initiation factor 4E (eIF4E)-binding protein 1 (4E-BP1), leading to suppression of c-Myc translation and silencing of c-Myc-dependent transcription. The synergistic cytotoxicity of TC was rescued by overexpression of eIF4E or c-Myc. TGR-1202, but not other PI3Kδ inhibitors, inhibited casein kinase-1 ε (CK1ε). Targeting CK1ε using a selective chemical inhibitor or short hairpin RNA complements the effects of idelalisib, as a single agent or in combination with carfilzomib, in repressing phosphorylation of 4E-BP1 and the protein level of c-Myc. These results suggest that TGR-1202 is a dual PI3Kδ/CK1ε inhibitor, which may in part explain the clinical activity of TGR-1202 in aggressive lymphoma not found with idelalisib. Targeting CK1ε should become an integral part of therapeutic strategies targeting translation of oncogenes such as c-Myc. © 2017 by The American Society of Hematology.

  7. SIRT1 promotes N-Myc oncogenesis through a positive feedback loop involving the effects of MKP3 and ERK on N-Myc protein stability.

    Directory of Open Access Journals (Sweden)

    Glenn M Marshall

    2011-06-01

    Full Text Available The N-Myc oncoprotein is a critical factor in neuroblastoma tumorigenesis which requires additional mechanisms converting a low-level to a high-level N-Myc expression. N-Myc protein is stabilized when phosphorylated at Serine 62 by phosphorylated ERK protein. Here we describe a novel positive feedback loop whereby N-Myc directly induced the transcription of the class III histone deacetylase SIRT1, which in turn increased N-Myc protein stability. SIRT1 binds to Myc Box I domain of N-Myc protein to form a novel transcriptional repressor complex at gene promoter of mitogen-activated protein kinase phosphatase 3 (MKP3, leading to transcriptional repression of MKP3, ERK protein phosphorylation, N-Myc protein phosphorylation at Serine 62, and N-Myc protein stabilization. Importantly, SIRT1 was up-regulated, MKP3 down-regulated, in pre-cancerous cells, and preventative treatment with the SIRT1 inhibitor Cambinol reduced tumorigenesis in TH-MYCN transgenic mice. Our data demonstrate the important roles of SIRT1 in N-Myc oncogenesis and SIRT1 inhibitors in the prevention and therapy of N-Myc-induced neuroblastoma.

  8. GenoMycDB: a database for comparative analysis of mycobacterial genes and genomes.

    Science.gov (United States)

    Catanho, Marcos; Mascarenhas, Daniel; Degrave, Wim; Miranda, Antonio Basílio de

    2006-03-31

    Several databases and computational tools have been created with the aim of organizing, integrating and analyzing the wealth of information generated by large-scale sequencing projects of mycobacterial genomes and those of other organisms. However, with very few exceptions, these databases and tools do not allow for massive and/or dynamic comparison of these data. GenoMycDB (http://www.dbbm.fiocruz.br/GenoMycDB) is a relational database built for large-scale comparative analyses of completely sequenced mycobacterial genomes, based on their predicted protein content. Its central structure is composed of the results obtained after pair-wise sequence alignments among all the predicted proteins coded by the genomes of six mycobacteria: Mycobacterium tuberculosis (strains H37Rv and CDC1551), M. bovis AF2122/97, M. avium subsp. paratuberculosis K10, M. leprae TN, and M. smegmatis MC2 155. The database stores the computed similarity parameters of every aligned pair, providing for each protein sequence the predicted subcellular localization, the assigned cluster of orthologous groups, the features of the corresponding gene, and links to several important databases. Tables containing pairs or groups of potential homologs between selected species/strains can be produced dynamically by user-defined criteria, based on one or multiple sequence similarity parameters. In addition, searches can be restricted according to the predicted subcellular localization of the protein, the DNA strand of the corresponding gene and/or the description of the protein. Massive data search and/or retrieval are available, and different ways of exporting the result are offered. GenoMycDB provides an on-line resource for the functional classification of mycobacterial proteins as well as for the analysis of genome structure, organization, and evolution.

  9. Myc contribution to γ-ray induced thymic lymphomas in mice of different genetic predispositions

    International Nuclear Information System (INIS)

    Sato, Toshihiro

    2008-01-01

    Myc gene has been suggested to be one of radiation targets in early genesis of γ ray-induced thymic lymphoma where Myc trisomy often occurs, and Myc activation results in p53 activation and apoptosis. The purpose of this study is to see the effects of radiation and mutation on Myc activation in the mouse. The lymphoma was induced by a single exposure of 3 Gy γ ray in BALB/c Bcl11b/Rit+/- and MSM p53-/- mice at 4 weeks after birth and by 4 weekly exposures of 2.5 Gy in p53+/- mouse. Genetic allele analysis for trisomy identification in the lymphoma was done by quantitative PCR using brain DNA as a control. Myc trisomy was found in the lymphoma of p53+/- mouse in 62% (23/37 animals) and of p53+/+, 66% (23/25), a similar frequency, suggesting that the target of radiation was not only the Myc activation. In addition, Myc trisomy frequency was 15% (4/27) in the lymphoma of Bcl11b+/+p53+/- and 36% (9/25), in heterozygote Bcl11b+/-. This finding suggested that the functional failure of Bcl11b reduced the contribution of Myc trisomy to the genesis. It was concluded that contribution of Myc trisomy to genesis of the lymphoma was dependent on genetic predisposition, and Myc-activated-, Bcl11b/Rit1-signal pathways played a parallel role in the genesis. (R.T.)

  10. Small Molecule Microarrays Enable the Identification of a Selective, Quadruplex-Binding Inhibitor of MYC Expression.

    Science.gov (United States)

    Felsenstein, Kenneth M; Saunders, Lindsey B; Simmons, John K; Leon, Elena; Calabrese, David R; Zhang, Shuling; Michalowski, Aleksandra; Gareiss, Peter; Mock, Beverly A; Schneekloth, John S

    2016-01-15

    The transcription factor MYC plays a pivotal role in cancer initiation, progression, and maintenance. However, it has proven difficult to develop small molecule inhibitors of MYC. One attractive route to pharmacological inhibition of MYC has been the prevention of its expression through small molecule-mediated stabilization of the G-quadruplex (G4) present in its promoter. Although molecules that bind globally to quadruplex DNA and influence gene expression are well-known, the identification of new chemical scaffolds that selectively modulate G4-driven genes remains a challenge. Here, we report an approach for the identification of G4-binding small molecules using small molecule microarrays (SMMs). We use the SMM screening platform to identify a novel G4-binding small molecule that inhibits MYC expression in cell models, with minimal impact on the expression of other G4-associated genes. Surface plasmon resonance (SPR) and thermal melt assays demonstrated that this molecule binds reversibly to the MYC G4 with single digit micromolar affinity, and with weaker or no measurable binding to other G4s. Biochemical and cell-based assays demonstrated that the compound effectively silenced MYC transcription and translation via a G4-dependent mechanism of action. The compound induced G1 arrest and was selectively toxic to MYC-driven cancer cell lines containing the G4 in the promoter but had minimal effects in peripheral blood mononucleocytes or a cell line lacking the G4 in its MYC promoter. As a measure of selectivity, gene expression analysis and qPCR experiments demonstrated that MYC and several MYC target genes were downregulated upon treatment with this compound, while the expression of several other G4-driven genes was not affected. In addition to providing a novel chemical scaffold that modulates MYC expression through G4 binding, this work suggests that the SMM screening approach may be broadly useful as an approach for the identification of new G4-binding small

  11. Myc-dependent genome instability and lifespan in Drosophila.

    Directory of Open Access Journals (Sweden)

    Christina Greer

    Full Text Available The Myc family of transcription factors are key regulators of cell growth and proliferation that are dysregulated in a large number of human cancers. When overexpressed, Myc family proteins also cause genomic instability, a hallmark of both transformed and aging cells. Using an in vivo lacZ mutation reporter, we show that overexpression of Myc in Drosophila increases the frequency of large genome rearrangements associated with erroneous repair of DNA double-strand breaks (DSBs. In addition, we find that overexpression of Myc shortens adult lifespan and, conversely, that Myc haploinsufficiency reduces mutation load and extends lifespan. Our data provide the first evidence that Myc may act as a pro-aging factor, possibly through its ability to greatly increase genome instability.

  12. Establishment of c-myc-immortalized Kupffer cell line from a C57BL/6 mouse strain

    Directory of Open Access Journals (Sweden)

    Hiroshi Kitani

    2014-01-01

    Full Text Available We recently demonstrated in several mammalian species, a novel procedure to obtain liver-macrophages (Kupffer cells in sufficient numbers and purity using a mixed primary culture of hepatocytes. In this study, we applied this method to the C57BL/6 mouse liver and established an immortalized Kupffer cell line from this mouse strain. The hepatocytes from the C57BL/6 adult mouse liver were isolated by a two-step collagenase perfusion method and cultured in T25 culture flasks. Similar to our previous studies, the mouse hepatocytes progressively changed their morphology into a fibroblastic appearance after a few days of culture. After 7–10 days of culture, Kupffer-like cells, which were contaminants in the hepatocyte fraction at the start of the culture, actively proliferated on the mixed fibroblastic cell sheet. At this stage, a retroviral vector containing the human c-myc oncogene and neomycin resistance gene was introduced into the mixed culture. Gentle shaking of the culture flask, followed by the transfer and brief incubation of the culture supernatant, resulted in a quick and selective adhesion of Kupffer cells to a plastic dish surface. After selection with G418 and cloning by limiting dilutions, a clonal cell line (KUP5 was established. KUP5 cells displayed typical macrophage morphology and were stably passaged at 4–5 days intervals for more than 5 months, with a population doubling time of 19 h. KUP5 cells are immunocytochemically positive for mouse macrophage markers, such as Mac-1, F4/80. KUP5 cells exhibited substantial phagocytosis of polystyrene microbeads and the release of inflammatory cytokines upon lipopolysaccharide stimulation. Taken together, KUP5 cells provide a useful means to study the function of Kupffer cells in vitro.

  13. Two human homeobox genes, c1 and c8: structure analysis and expression in embryonic development.

    Science.gov (United States)

    Simeone, A; Mavilio, F; Acampora, D; Giampaolo, A; Faiella, A; Zappavigna, V; D'Esposito, M; Pannese, M; Russo, G; Boncinelli, E

    1987-07-01

    Two human cDNA clones (HHO.c1.95 and HHO.c8.5111) containing a homeobox region have been characterized, and the respective genomic regions have been partially analyzed. Expression of the corresponding genes, termed c1 and c8, was evaluated in different organs and body parts during human embryonic/fetal development. HHO.c1.95 apparently encodes a 217-amino acid protein containing a class I homeodomain that shares 60 out of 61 amino acid residues with the Antennapedia homeodomain of Drosophila melanogaster. HHO.c8.5111 encodes a 153-amino acid protein containing a homeodomain identical to that of the frog AC1 gene. Clones HHO.c1 and HHO.c8 detect by blot-hydridization one and two specific polyadenylylated transcripts, respectively. These are differentially expressed in spinal cord, backbone rudiments, limb buds (or limbs), heart, and skin of human embryos and early fetuses in the 5- to 9-week postfertilization period, thus suggesting that the c1 and c8 genes play a key role in a variety of developmental processes. Together, the results of the embryonic/fetal expression of c1 and c8 and those of two previously analyzed genes (c10 and c13) indicate a coherent pattern of expression of these genes in early human ontogeny.

  14. Two human homeobox genes, c1 and c8: structure analysis and expression in embryonic development

    International Nuclear Information System (INIS)

    Simeone, A.; Mavilio, F.; Acampora, D.

    1987-01-01

    Two human cDNA clones (HHO.c1.95 and HHO.c8.5111) containing a homeobox region have been characterized, and the respective genomic regions have been partially analyzed. Expression of the corresponding genes, termed c1 and c8, was evaluated in different organs and body parts during human embryonic/fetal development. HHO.c1.95 apparently encodes a 217-amino acid protein containing a class I homeodomain that shares 60 out of 61 amino acid residues with the Antennapedia homeodomain of Drosophila melanogaster. HHO.c8.5111 encodes a 153-amino acid protein containing a homeodomains identical to that of the frog AC1 gene. Clones HHO.c1 and HHO.c8 detect by blot-hybridization one and two specific polyadenylylated transcripts, respectively. These are differentially expressed in spinal cord, backbone rudiments, limb buds (or limbs), heart, and skin of human embryos and early fetuses in the 5- to 9-week postfertilization period, thus suggesting that the c1 and c8 genes play a key role in a variety of developmental processes. Together, the results of the embryonic/fetal expression of c1 and c8 and those of two previously analyzed genes (c10 and c13) indicate a coherent pattern of expression of these genes in early human ontogeny

  15. FoxO3A promotes metabolic adaptation to hypoxia by antagonizing Myc function

    OpenAIRE

    Jensen, Kim Steen; Binderup, Tina; Jensen, Klaus Thorleif; Therkelsen, Ib; Borup, Rehannah; Nilsson, Elise; Multhaupt, Hinke; Bouchard, Caroline; Quistorff, Bjørn; Kjær, Andreas; Landberg, Göran; Staller, Peter

    2011-01-01

    This paper characterizes FoxO3A as required for hypoxic suppression of mitochondrial mass, oxygen consumption, and ROS production. Mechanistically, FoxO3A is shown to promote hypoxic cell survival by directly antagonizing c-Myc at nuclear encoded mitochondrial genes.

  16. RNA-Guided Activation of Pluripotency Genes in Human Fibroblasts

    DEFF Research Database (Denmark)

    Xiong, Kai; Zhou, Yan; Blichfeld, Kristian Aabo

    2017-01-01

    -associated protein 9 (dCas9)-VP64 (CRISPRa) alone, or a combination of dCas9-VP64 and MS2-P65-HSF1 [synergistic activation mediator (SAM) system] mediated activation of five pluripotency genes: KLF4 (K), LIN28 (L), MYC (M), OCT4 (O), and SOX2 (S) in human cells (HEK293T, HeLa, HepG2, and primary fibroblasts...... could be obtained from these SAM fibroblasts. In conclusion, our study showed that CRISPR/Cas9-based ATFs are potent to activate and maintain transcription of endogenous human pluripotent genes. However, future improvements of the system are still required to improve activation efficiency and cellular...

  17. SirT1 confers hypoxia-induced radioresistance via the modulation of c-Myc stabilization on hepatoma cells

    International Nuclear Information System (INIS)

    Xie Yuexia; Zhang Jianghong; Shao Chunlin; Xu Yanwu

    2012-01-01

    Intratumoral hypoxia is an important contributory factor to tumor cell resistance to radiotherapy. SirT1, a nicotinamide adenine dinucleotide (NAD + )-dependent histone/protein deacetylase, has been linked to the decrease of radiation-induced DNA damage and seems to be critical for cancer therapy. The purpose of this study was to investigate the role of SirT1 in hypoxia-induced radiation response on hepatoma cells. It was found that the administration with resveratrol, a putative SirT1 activator, enhanced the resistance of HepG2 cells against radiation-induced DNA damage of MN formation under hypoxia condition; while nicotinamide, a well-known SirT1 inhibitor, sensitized this radiation damage. Nevertheless, pretreatment of cells with 10058-F4, a specific inhibitor of c-Myc, almost eliminated the nicotinamide-induced radiosensitive effect. Further studies revealed that resveratrol inhibited c-Myc protein accumulation via up-regulation of SirT1 expression and deacetylase activity, and this loss of c-Myc protein was abolished by inhibiting its degradation in the presence of MG132, a potent inhibitor of proteasome. In contrast, nicotinamide attenuated c-Myc protein degradation induced by radiation under hypoxia through inhibition of SirT1 deacetylase activity. Our findings suggest that SirT1 could serve as a novel potent target of radiation-induced DNA damage and thus as a potential strategy to advance the efficiency of radiation therapy in hepatoma entities. (author)

  18. MYC Immunohistochemistry to Identify MYC-Driven B-Cell Lymphomas in Clinical Practice.

    Science.gov (United States)

    Kluk, Michael J; Ho, Caleb; Yu, Hongbo; Chen, Benjamin J; Neuberg, Donna S; Dal Cin, Paola; Woda, Bruce A; Pinkus, Geraldine S; Rodig, Scott J

    2016-02-01

    Immunohistochemistry with anti-MYC antibody (MYC IHC) detects MYC protein in fixed samples of aggressive B-cell lymphomas and, according to the number of positive staining tumor nuclei, facilitates tumor subclassification, predicts underlying MYC rearrangements, and stratifies patient outcome. We aimed to determine the performance of MYC IHC in clinical practice. We reviewed MYC IHC performed on control specimens and 256 aggressive B-cell lymphomas and compared clinically reported IHC scores with experts' review. Control tissues showed less than 5% variation in daily IHC staining. Reported and expert IHC scores were well correlated (r = 0.86) with an SD of 14.2%. Reported IHC scores 30% or less and 70% or more were accurate (94.5%) compared with experts in categorizing tumors as "MYC IHC-Low" and "MYC IHC-High," respectively, but scores 40% to 60% were not (60.3%). The mean IHC score among lymphomas with MYC rearrangements was 80%, but with a large range of scores (20%-100%). There was no statistically significant association between IHC score and MYC copy number. Under optimal conditions, clinically reported MYC IHC scores are concordant with expert scores within 15%. MYC IHC does not capture all B-cell lymphomas with MYC rearrangements, however. MYC IHC and MYC fluorescence in situ hybridization are both recommended to identify MYC-driven B-cell lymphomas. © American Society for Clinical Pathology, 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  19. MYC Amplification in Angiosarcoma Arising from an Arteriovenous Graft Site

    Directory of Open Access Journals (Sweden)

    Kristen M. Paral

    2015-01-01

    Full Text Available Angiosarcoma arising in association with an arteriovenous graft (AVG or fistula is a unique clinicopathologic scenario that appears to be gaining recognition in the literature. Among reported cases, none has described high-level MYC gene amplification, a genetic aberration that is increasingly unifying the various clinicopathologic subdivisions of angiosarcoma. We therefore report the MYC gene status in a case of angiosarcoma arising at an AVG site.

  20. Conserved features of cancer cells define their sensitivity to HAMLET-induced death; c-Myc and glycolysis.

    Science.gov (United States)

    Storm, P; Aits, S; Puthia, M K; Urbano, A; Northen, T; Powers, S; Bowen, B; Chao, Y; Reindl, W; Lee, D Y; Sullivan, N L; Zhang, J; Trulsson, M; Yang, H; Watson, J D; Svanborg, C

    2011-12-01

    HAMLET is the first member of a new family of tumoricidal protein-lipid complexes that kill cancer cells broadly, while sparing healthy, differentiated cells. Many and diverse tumor cell types are sensitive to the lethal effect, suggesting that HAMLET identifies and activates conserved death pathways in cancer cells. Here, we investigated the molecular basis for the difference in sensitivity between cancer cells and healthy cells. Using a combination of small-hairpin RNA (shRNA) inhibition, proteomic and metabolomic technology, we identified the c-Myc oncogene as one essential determinant of HAMLET sensitivity. Increased c-Myc expression levels promoted sensitivity to HAMLET and shRNA knockdown of c-Myc suppressed the lethal response, suggesting that oncogenic transformation with c-Myc creates a HAMLET-sensitive phenotype. Furthermore, HAMLET sensitivity was modified by the glycolytic state of tumor cells. Glucose deprivation sensitized tumor cells to HAMLET-induced cell death and in the shRNA screen, hexokinase 1 (HK1), 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 1 and hypoxia-inducible factor 1α modified HAMLET sensitivity. HK1 was shown to bind HAMLET in a protein array containing ∼8000 targets, and HK activity decreased within 15 min of HAMLET treatment, before morphological signs of tumor cell death. In parallel, HAMLET triggered rapid metabolic paralysis in carcinoma cells. Tumor cells were also shown to contain large amounts of oleic acid and its derivatives already after 15 min. The results identify HAMLET as a novel anti-cancer agent that kills tumor cells by exploiting unifying features of cancer cells such as oncogene addiction or the Warburg effect.

  1. Conserved features of cancer cells define their sensitivity of HAMLET-induced death; c-Myc and glycolysis

    Science.gov (United States)

    Storm, Petter; Puthia, Manoj Kumar; Aits, Sonja; Urbano, Alexander; Northen, Trent; Powers, Scott; Bowen, Ben; Chao, Yinxia; Reindl, Wolfgang; Lee, Do Yup; Sullivan, Nancy Liu; Zhang, Jianping; Trulsson, Maria; Yang, Henry; Watson, James; Svanborg, Catharina

    2014-01-01

    HAMLET is the first member of a new family of tumoricidal protein-lipid complexes that kill cancer cells broadly, while sparing healthy, differentiated cells. Many and diverse tumor cell types are sensitive to the lethal effect, suggesting that HAMLET identifies and activates conserved death pathways in cancer cells. Here we investigated the molecular basis for the difference in sensitivity between cancer cells and healthy cells. Using a combination of small hairpin RNA inhibition, proteomic and metabolomic technology we identified the c-Myc oncogene as one essential determinant of HAMLET sensitivity. Increased c-Myc expression levels promoted the sensitivity to HAMLET and shRNA knockdown of c-Myc suppressed the lethal response, suggesting that oncogenic transformation with c-Myc creates a HAMLET-sensitive phenotype. Furthermore, the HAMLET sensitivity was modified by the glycolytic state of the tumor cells. Glucose deprivation sensitized tumor cells to HAMLET-induced cell death and in the shRNA screen Hexokinase 1, PFKFB1 and HIF1α modified HAMLET sensitivity. Hexokinase 1 was shown to bind HAMLET in a protein array containing approximately 8000 targets and Hexokinase activity decreased within 15 minutes of HAMLET treatment, prior to morphological signs of tumor cell death. In parallel, HAMLET triggered rapid metabolic paralysis in carcinoma cells. The glycolytic machinery was modified and glycolysis was shifted towards the pentose phosphate pathway. Tumor cells were also shown to contain large amounts of oleic acid and its derivatives already after 15 minutes. The results identify HAMLET as a novel anti-cancer agent that kills tumor cells by exploiting unifying features of cancer cells such as oncogene-addiction or the Warburg effect. PMID:21643007

  2. Induction of Pluripotency in Adult Equine Fibroblasts without c-MYC

    Directory of Open Access Journals (Sweden)

    Khodadad Khodadadi

    2012-01-01

    Full Text Available Despite tremendous efforts on isolation of pluripotent equine embryonic stem (ES cells, to date there are few reports about successful isolation of ESCs and no report of in vivo differentiation of this important companion species. We report the induction of pluripotency in adult equine fibroblasts via retroviral transduction with three transcription factors using OCT4, SOX2, and KLF4 in the absence of c-MYC. The cell lines were maintained beyond 27 passages (more than 11 months and characterized. The equine iPS (EiPS cells stained positive for alkaline phosphatase by histochemical staining and expressed OCT4, NANOG, SSEA1, and SSEA4. Gene expression analysis of the cells showed the expression of OCT4, SOX2 NANOG, and STAT3. The cell lines retained a euploid chromosome count of 64 after long-term culture cryopreservation. The EiPS demonstrated differentiation capacity for the three embryonic germ layers both in vitro by embryoid bodies (EBs formation and in vivo by teratoma formation. In conclusion, we report the derivation of iPS cells from equine adult fibroblasts and long-term maintenance using either of the three reprogramming factors.

  3. Targeting human c-Myc promoter duplex DNA with actinomycin D by use of multi-way analysis of quantum-dot-mediated fluorescence resonance energy transfer

    DEFF Research Database (Denmark)

    Gholami, Somayeh; Kompany Zare, Mohsen

    2013-01-01

    Actinomycin D (Act D), an oncogenic c-Myc promoter binder, interferes with the action of RNA polymerase. There is great demand for high-throughput technology able to monitor the activity of DNA-binding drugs. To this end, binding of 7-aminoactinomycin D (7AAD) to the duplex c-Myc promoter...... pairs resulted in efficient energy transfer from drug to QD via fluorescence resonance energy transfer (FRET). Multi-way analysis of the three-way data array obtained from titration experiments was performed by use of restricted Tucker3 and hard trilinear decomposition (HTD). These techniques enable...... the important advantage over univariate classical methods of enabling us to investigate the source of variance in the fluorescence signal of the DNA-drug complex. It was established that hard trilinear decomposition analysis of FRET-measured data overcomes the problem of rank deficiency, enabling calculation...

  4. N-Myc Differentially Regulates Expression of MXI1 Isoforms in Neuroblastoma

    Directory of Open Access Journals (Sweden)

    Michael B. Armstrong

    2013-12-01

    Full Text Available Amplification of the MYCN proto-oncogene is associated with a poor prognosis in patients with metastatic neuroblastoma (NB. MYCN encodes the N-Myc protein, a transcriptional regulator that dimerizes with the Max transcription factor, binds to E-box DNA sequences, and regulates genes involved in cell growth and apoptosis. Overexpression of N-Myc leads to transcriptional activation and an increase in NB cell proliferation. Mxi1, a member of the Myc family of transcriptional regulators, also binds to Max. However, Mxi1 is a transcriptional repressor and inhibits proliferation of NB cells, suggesting that Mxi1 functions as an N-Myc antagonist. Our laboratory previously identified Mxi1-0, an alternatively transcribed Mxi1 isoform. Mxi1-0 has properties distinct from those of Mxi1; in contrast to Mxi1, Mxi1-0 is unable to suppress c-Myc-dependent transcription. We now show that Mxi1-0 expression increases in response to MYCN overexpression in NB cells, with a positive correlation between MYCN and MXI1-0 RNA levels. We also show that N-Myc expression differentially regulates the MXI1 and MXI1-0 promoters: Increased MYCN expression suppresses MXI1 promoter activity while enhancing transcription through the MXI1-0 promoter. Finally, induction of Mxi1-0 leads to increased proliferation, whereas expression of Mxi1 inhibits cell growth, indicating differential roles for these two proteins. These data suggest that N-Myc differentially regulates the expression of MXI1 and MXI1-0 and can alter the balance between the two transcription factors. Furthermore, MXI1-0 appears to be a downstream target of MYCN-dependent signaling pathways and may contribute to N-Myc-dependent cell growth and proliferation.

  5. Synergistic Induction of Potential Warburg Effect in Zebrafish Hepatocellular Carcinoma by Co-Transgenic Expression of Myc and xmrk Oncogenes.

    Directory of Open Access Journals (Sweden)

    Zhen Li

    Full Text Available Previously we have generated inducible liver tumor models by transgenic expression of Myc or xmrk (activated EGFR homolog oncogenes in zebrafish. To investigate the interaction of the two oncogenes, we crossed the two transgenic lines and observed more severe and faster hepatocarcinogenesis in Myc/xmrk double transgenic zebrafish than either single transgenic fish. RNA-Seq analyses revealed distinct changes in many molecular pathways among the three types of liver tumors. In particular, we found dramatic alteration of cancer metabolism based on the uniquely enriched pathways in the Myc/xmrk tumors. Critical glycolytic genes including hk2, pkm and ldha were significantly up-regulated in Myc/xmrk tumors but not in either single oncogene-induced tumors, suggesting a potential Warburg effect. In RT-qPCR analyses, the specific pkm2 isoformin Warburg effect was found to be highly enriched in the Myc/xmrk tumors but not in Myc or xmrk tumors, consistent with the observations in many human cancers with Warburg effect. Moreover, the splicing factor genes (hnrnpa1, ptbp1a, ptbp1b and sfrs3b responsible for generating the pkm isoform were also greatly up-regulated in the Myc/xmrk tumors. As Pkm2 isoform is generally inactive and causes incomplete glycolysis to favor anabolism and tumor growth, by treatment with a Pkm2-specific activator, TEPP-46, we further demonstrated that activation of Pkm2 suppressed the growth of oncogenic liver as well as proliferation of liver cells. Collectively, our Myc/xmrk zebrafish model suggests synergetic effect of EGFR and MYC in triggering Warburg effect in the HCC formation and may provide a promising in vivo model for Warburg effect.

  6. Vitamin K2 and cotylenin A synergistically induce monocytic differentiation and growth arrest along with the suppression of c-MYC expression and induction of cyclin G2 expression in human leukemia HL-60 cells.

    Science.gov (United States)

    Maniwa, Yasuhisa; Kasukabe, Takashi; Kumakura, Shunichi

    2015-08-01

    Although all-trans retinoic acid (ATRA) is a standard and effective drug used for differentiation therapy in acute promyelocytic leukemia, ATRA-resistant leukemia cells ultimately emerge during this treatment. Therefore, the development of new drugs or effective combination therapy is urgently needed. We demonstrate that the combined treatment of vitamin K2 and cotylenin A synergistically induced monocytic differentiation in HL-60 cells. This combined treatment also synergistically induced NBT-reducing activity and non-specific esterase-positive cells as well as morphological changes to monocyte/macrophage-like cells. Vitamin K2 and cotylenin A cooperatively inhibited the proliferation of HL-60 cells in short-term and long-term cultures. This treatment also induced growth arrest at the G1 phase. Although 5 µg/ml cotylenin A or 5 µM vitamin K2 alone reduced c-MYC gene expression in HL-60 cells to approximately 45% or 80% that of control cells, respectively, the combined treatment almost completely suppressed c-MYC gene expression. We also demonstrated that the combined treatment of vitamin K2 and cotylenin A synergistically induced the expression of cyclin G2, which had a positive effect on the promotion and maintenance of cell cycle arrest. These results suggest that the combination of vitamin K2 and cotylenin A has therapeutic value in the treatment of acute myeloid leukemia.

  7. MYC protein expression and genetic alterations have prognostic impact in patients with diffuse large B-cell lymphoma treated with immunochemotherapy.

    Science.gov (United States)

    Valera, Alexandra; López-Guillermo, Armando; Cardesa-Salzmann, Teresa; Climent, Fina; González-Barca, Eva; Mercadal, Santiago; Espinosa, Iñigo; Novelli, Silvana; Briones, Javier; Mate, José L; Salamero, Olga; Sancho, Juan M; Arenillas, Leonor; Serrano, Sergi; Erill, Nadina; Martínez, Daniel; Castillo, Paola; Rovira, Jordina; Martínez, Antonio; Campo, Elias; Colomo, Luis

    2013-10-01

    MYC alterations influence the survival of patients with diffuse large B-cell lymphoma. Most studies have focused on MYC translocations but there is little information regarding the impact of numerical alterations and protein expression. We analyzed the genetic alterations and protein expression of MYC, BCL2, BCL6, and MALT1 in 219 cases of diffuse large B-cell lymphoma. MYC rearrangement occurred as the sole abnormality (MYC single-hit) in 3% of cases, MYC and concurrent BCL2 and/or BCL6 rearrangements (MYC double/triple-hit) in 4%, MYC amplifications in 2% and MYC gains in 19%. MYC single-hit, MYC double/triple-hit and MYC amplifications, but not MYC gains or other gene rearrangements, were associated with unfavorable progression-free survival and overall survival. MYC protein expression, evaluated using computerized image analysis, captured the unfavorable prognosis of MYC translocations/amplifications and identified an additional subset of patients without gene alterations but with similar poor prognosis. Patients with tumors expressing both MYC/BCL2 had the worst prognosis, whereas those with double-negative tumors had the best outcome. High MYC expression was associated with shorter overall survival irrespectively of the International Prognostic Index and BCL2 expression. In conclusion, MYC protein expression identifies a subset of diffuse large B-cell lymphoma with very poor prognosis independently of gene alterations and other prognostic parameters.

  8. Course of c-myc mRNA expression in the regenerating mouse testis determined by competitive reverse transcriptase polymerase chain reaction.

    Science.gov (United States)

    Amendola, R

    1994-11-01

    The c-myc proto-oncogene is a reliable marker of the "G0-early G1" transition, and its down-regulation is believed to be necessary to obtain cellular differentiation. In murine spermatogenesis, the level of c-myc transcripts does not correlate with the rate of cellular division. Proliferation of supposed staminal spermatogonia to reproduce themselves is induced with a local 5 Gy X-ray dose in 90-day-old C57Bl/6 mice. c-myc quantification by a newly developed competitive reverse transcriptase polymerase chain reaction (RT-PCR) was carried out to follow the expression course of this proto-oncogene. Damage and restoration of spermatogenesis were analyzed at days 3, 6, 9, 10, 13, 30, and 60 after injury by relative testes/body weight determination and histological examination. Proliferative status was determined by histone H3 Northern blot analysis. c-myc mRNA level was 10 times higher after 3 days in the irradiated animals compared to the controls. An increasing number of copies were noted up to 10 days, but promptly decreased to the base level found for irradiated mice from 13 to 60 days. Interestingly, the expression of histone H3 detected S phase only in testes at 60 days from damage.

  9. Targeting of the MYCN Protein with Small Molecule c-MYC Inhibitors

    OpenAIRE

    Müller, Inga; Larsson, Karin; Frenzel, Anna; Oliynyk, Ganna; Zirath, Hanna; Prochownik, Edward V.; Westwood, Nicholas J.; Henriksson, Marie Arsenian

    2014-01-01

    This study was funded by grants from the Swedish Research Council and the Swedish Cancer Society. IM and HZ were recipients of graduate student grants from KI (KID), MAH was recipient of a Senior Investigator Award from the Swedish Cancer Society, and NJW was a Royal Society University Research Fellow when this work began. Members of the MYC family are the most frequently deregulated oncogenes in human cancer and are often correlated with aggressive disease and/or poorly differentiated tum...

  10. MYC activation is a hallmark of cancer initiation and maintenance.

    Science.gov (United States)

    Gabay, Meital; Li, Yulin; Felsher, Dean W

    2014-06-02

    The MYC proto-oncogene has been implicated in the pathogenesis of most types of human tumors. MYC activation alone in many normal cells is restrained from causing tumorigenesis through multiple genetic and epigenetically controlled checkpoint mechanisms, including proliferative arrest, apoptosis, and cellular senescence. When pathologically activated in a permissive epigenetic and/or genetic context, MYC bypasses these mechanisms, enforcing many of the "hallmark" features of cancer, including relentless tumor growth associated with DNA replication and transcription, cellular proliferation and growth, protein synthesis, and altered cellular metabolism. MYC mandates tumor cell fate, by inducing stemness and blocking cellular senescence and differentiation. Additionally, MYC orchestrates changes in the tumor microenvironment, including the activation of angiogenesis and suppression of the host immune response. Provocatively, brief or even partial suppression of MYC back to its physiological levels of activation can result in the restoration of intrinsic checkpoint mechanisms, resulting in acute and sustained tumor regression, associated with tumor cells undergoing proliferative arrest, differentiation, senescence, and apoptosis, as well as remodeling of the tumor microenvironment, recruitment of an immune response, and shutdown of angiogenesis. Hence, tumors appear to be "addicted" to MYC because of both tumor cell-intrinsic, cell-autonomous and host-dependent, immune cell-dependent mechanisms. Both the trajectory and persistence of many human cancers require sustained MYC activation. Multiscale mathematical modeling may be useful to predict when tumors will be addicted to MYC. MYC is a hallmark molecular feature of both the initiation and maintenance of tumorigenesis. Copyright © 2014 Cold Spring Harbor Laboratory Press; all rights reserved.

  11. N-Myc Differentially Regulates Expression of MXI1 Isoforms in Neuroblastoma1

    Science.gov (United States)

    Armstrong, Michael B; Mody, Rajen J; Ellis, D Christian; Hill, Adam B; Erichsen, David A; Wechsler, Daniel S

    2013-01-01

    Amplification of the MYCN proto-oncogene is associated with a poor prognosis in patients with metastatic neuroblastoma (NB). MYCN encodes the N-Myc protein, a transcriptional regulator that dimerizes with the Max transcription factor, binds to E-box DNA sequences, and regulates genes involved in cell growth and apoptosis. Overexpression of N-Myc leads to transcriptional activation and an increase in NB cell proliferation. Mxi1, a member of the Myc family of transcriptional regulators, also binds to Max. However, Mxi1 is a transcriptional repressor and inhibits proliferation of NB cells, suggesting that Mxi1 functions as an N-Myc antagonist. Our laboratory previously identified Mxi1-0, an alternatively transcribed Mxi1 isoform. Mxi1-0 has properties distinct from those of Mxi1; in contrast to Mxi1, Mxi1-0 is unable to suppress c-Myc-dependent transcription. We now show that Mxi1-0 expression increases in response to MYCN overexpression in NB cells, with a positive correlation between MYCN and MXI1-0 RNA levels. We also show that N-Myc expression differentially regulates the MXI1 and MXI1-0 promoters: Increased MYCN expression suppresses MXI1 promoter activity while enhancing transcription through the MXI1-0 promoter. Finally, induction of Mxi1-0 leads to increased proliferation, whereas expression of Mxi1 inhibits cell growth, indicating differential roles for these two proteins. These data suggest that N-Myc differentially regulates the expression of MXI1 and MXI1-0 and can alter the balance between the two transcription factors. Furthermore, MXI1-0 appears to be a downstream target of MYCN-dependent signaling pathways and may contribute to N-Myc-dependent cell growth and proliferation. PMID:24403858

  12. Myc/Mycn-mediated glycolysis enhances mouse spermatogonial stem cell self-renewal.

    Science.gov (United States)

    Kanatsu-Shinohara, Mito; Tanaka, Takashi; Ogonuki, Narumi; Ogura, Atsuo; Morimoto, Hiroko; Cheng, Pei Feng; Eisenman, Robert N; Trumpp, Andreas; Shinohara, Takashi

    2016-12-01

    Myc plays critical roles in the self-renewal division of various stem cell types. In spermatogonial stem cells (SSCs), Myc controls SSC fate decisions because Myc overexpression induces enhanced self-renewal division, while depletion of Max, a Myc-binding partner, leads to meiotic induction. However, the mechanism by which Myc acts on SSC fate is unclear. Here we demonstrate a critical link between Myc/Mycn gene activity and glycolysis in SSC self-renewal. In SSCs, Myc/Mycn are regulated by Foxo1, whose deficiency impairs SSC self-renewal. Myc/Mycn-deficient SSCs not only undergo limited self-renewal division but also display diminished glycolytic activity. While inhibition of glycolysis decreased SSC activity, chemical stimulation of glycolysis or transfection of active Akt1 or Pdpk1 (phosphoinositide-dependent protein kinase 1 ) augmented self-renewal division, and long-term SSC cultures were derived from a nonpermissive strain that showed limited self-renewal division. These results suggested that Myc-mediated glycolysis is an important factor that increases the frequency of SSC self-renewal division. © 2016 Kanatsu-Shinohara et al.; Published by Cold Spring Harbor Laboratory Press.

  13. Loss of connective tissue growth factor as an unfavorable prognosis factor activates miR-18b by PI3K/AKT/C-Jun and C-Myc and promotes cell growth in nasopharyngeal carcinoma.

    Science.gov (United States)

    Yu, X; Zhen, Y; Yang, H; Wang, H; Zhou, Y; Wang, E; Marincola, F M; Mai, C; Chen, Y; Wei, H; Song, Y; Lyu, X; Ye, Y; Cai, L; Wu, Q; Zhao, M; Hua, S; Fu, Q; Zhang, Y; Yao, K; Liu, Z; Li, X; Fang, W

    2013-05-16

    Connective tissue growth factor (CTGF) has different roles in different types of cancer. However, the involvement and molecular basis of CTGF in tumor progression and prognosis of human nasopharyngeal carcinoma (NPC) have almost never been reported. In this study, we observed that downregulated CTGF expression was significantly associated with NPC progression and poor prognosis. Knockdown of CTGF markedly elevated the ability of cell proliferation in vivo and in vitro. Subsequently, we discovered that the reduction of CTGF increased the expression of miR-18b, an oncomir-promoting cell proliferation. Further, we discovered that attenuated CTGF-mediated upregulation of miR-18b was dependent on the increased binding of transcription factors Jun proto-oncogene (C-Jun) and v-Myc myelocytomatosis viral oncogene homolog (C-Myc) to miR-18b promoter region via phosphoinositide 3-kinase (PI3K)/AKT pathway. Finally, we further found that miR-18b directly suppressed the expression of CTGF in NPC. In clinical fresh specimens, miR-18b was widely overexpressed and inversely correlated with CTGF expression in NPC. Our studies are the first to demonstrate that reduced CTGF as an unfavorable prognosis factor mediates the activation of miR-18b, an oncomir directly suppresses CTGF expression, by PI3K/AKT/C-Jun and C-Myc and promotes cell growth of NPC.

  14. Induction of apoptosis by 3-amino-6-(3-aminopropyl)-5,6-dihydro-5,11-dioxo-11H-indeno[1,2-c]isoquinoline via modulation of MAPKs (p38 and c-Jun N-terminal kinase) and c-Myc in HL-60 human leukemia cells.

    Science.gov (United States)

    Park, Eun-Jung; Kiselev, Evgeny; Conda-Sheridan, Martin; Cushman, Mark; Pezzuto, John M

    2012-03-23

    Recently, we reported that 3-amino-6-(3-aminopropyl)-5,6-dihydro-5,11-dioxo-11H-indeno[1,2-c]isoquinoline (AM6-36), sharing structural similarity with naturally occurring isoquinolines, induced activities mediated by retinoid X receptor (RXR) response element accompanied by antiproliferative effects on breast cancer cells. To further characterize the biologic potential of AM6-36, we currently report studies conducted with HL-60 human leukemia cells. AM6-36 significantly inhibited cellular proliferation in a dose- and time-dependent manner with an IC(50) value of 86 nM. When evaluated at low test concentrations (≤0.25 μM), AM6-36 induced arrest in the G2/M phase of the cell cycle. At higher concentrations (1 and 2 μM), the response shifted to apoptosis, which was consistent with the effect of AM6-36 on other apoptotic signatures including an increase of apoptotic annexin V(+) 7-AAD(-) cells, loss of mitochondrial membrane potential, induction of poly(ADP-ribose) polymerase cleavage, and activation of several caspases. These apoptotic effects are potentially due to up-regulation of p38 MAPK and JNK phosphorylation and down-regulation of c-Myc oncogene expression. Taken together, AM6-36 might serve as an effective anticancer agent by inducing G2/M cell cycle arrest and apoptosis through the activation of MAPKs and inhibition of c-Myc.

  15. Fisetin Enhances the Cytotoxicity of Gemcitabine by Down-regulating ERK-MYC in MiaPaca-2 Human Pancreatic Cancer Cells.

    Science.gov (United States)

    Kim, Nayoung; Kang, Min-Jung; Lee, Sang Hyub; Son, Jun Hyuk; Lee, Ji Eun; Paik, Woo Hyun; Ryu, Ji Kon; Kim, Yong-Tae

    2018-06-01

    Pancreatic cancer is a highly lethal malignancy with a poor prognosis. This study was set up to investigate the combined effect of gemcitabine and fisetin, a natural flavonoid from plants, on human pancreatic cancer cells. Meterials and Methods: Cytotoxic effect of fisetin in combination with gemcitabine on MiaPaca-2 cells was evaluated by the MTT assay, caspase 3/7 assay and propidium iodide/Annexin V. Extracellular signal-regulated kinase (ERK)-v-myc avian myelocytomatosis viral oncogene homolog (MYC) pathway was investigated by western blotting and quantitative real-time polymerase chain reaction. Combination treatment with fisetin and gemcitabine inhibited the proliferation of pancreatic cancer cells within 72 h and induced apoptosis, as indicated by activation of caspase 3/7. Fisetin down-regulated ERK at the protein and mRNA levels, and reduced ERK-induced MYC instability at the protein level. Fisetin sensitized human pancreatic cancer cells to gemcitabine-induced cytotoxicity through inhibition of ERK-MYC signaling. These results suggest that the combination of fisetin and gemcitabine could be developed as a novel potent therapeutic. Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  16. APTO-253 Stabilizes G-quadruplex DNA, Inhibits MYC Expression, and Induces DNA Damage in Acute Myeloid Leukemia Cells.

    Science.gov (United States)

    Local, Andrea; Zhang, Hongying; Benbatoul, Khalid D; Folger, Peter; Sheng, Xia; Tsai, Cheng-Yu; Howell, Stephen B; Rice, William G

    2018-06-01

    APTO-253 is a phase I clinical stage small molecule that selectively induces CDKN1A (p21), promotes G 0 -G 1 cell-cycle arrest, and triggers apoptosis in acute myeloid leukemia (AML) cells without producing myelosuppression in various animal species and humans. Differential gene expression analysis identified a pharmacodynamic effect on MYC expression, as well as induction of DNA repair and stress response pathways. APTO-253 was found to elicit a concentration- and time-dependent reduction in MYC mRNA expression and protein levels. Gene ontogeny and structural informatic analyses suggested a mechanism involving G-quadruplex (G4) stabilization. Intracellular pharmacokinetic studies in AML cells revealed that APTO-253 is converted intracellularly from a monomer to a ferrous complex [Fe(253) 3 ]. FRET assays demonstrated that both monomeric APTO-253 and Fe(253) 3 stabilize G4 structures from telomeres, MYC, and KIT promoters but do not bind to non-G4 double-stranded DNA. Although APTO-253 exerts a host of mechanistic sequelae, the effect of APTO-253 on MYC expression and its downstream target genes, on cell-cycle arrest, DNA damage, and stress responses can be explained by the action of Fe(253) 3 and APTO-253 on G-quadruplex DNA motifs. Mol Cancer Ther; 17(6); 1177-86. ©2018 AACR . ©2018 American Association for Cancer Research.

  17. Aberrant DNA Methylation in Human iPSCs Associates with MYC-Binding Motifs in a Clone-Specific Manner Independent of Genetics.

    Science.gov (United States)

    Panopoulos, Athanasia D; Smith, Erin N; Arias, Angelo D; Shepard, Peter J; Hishida, Yuriko; Modesto, Veronica; Diffenderfer, Kenneth E; Conner, Clay; Biggs, William; Sandoval, Efren; D'Antonio-Chronowska, Agnieszka; Berggren, W Travis; Izpisua Belmonte, Juan Carlos; Frazer, Kelly A

    2017-04-06

    Induced pluripotent stem cells (iPSCs) show variable methylation patterns between lines, some of which reflect aberrant differences relative to embryonic stem cells (ESCs). To examine whether this aberrant methylation results from genetic variation or non-genetic mechanisms, we generated human iPSCs from monozygotic twins to investigate how genetic background, clone, and passage number contribute. We found that aberrantly methylated CpGs are enriched in regulatory regions associated with MYC protein motifs and affect gene expression. We classified differentially methylated CpGs as being associated with genetic and/or non-genetic factors (clone and passage), and we found that aberrant methylation preferentially occurs at CpGs associated with clone-specific effects. We further found that clone-specific effects play a strong role in recurrent aberrant methylation at specific CpG sites across different studies. Our results argue that a non-genetic biological mechanism underlies aberrant methylation in iPSCs and that it is likely based on a probabilistic process involving MYC that takes place during or shortly after reprogramming. Published by Elsevier Inc.

  18. Investigation of miRNA Biology by Bioinformatic Tools and Impact of miRNAs in Colorectal Cancer: Regulatory Relationship of c-Myc and p53 with miRNAs

    Directory of Open Access Journals (Sweden)

    Yaguang Xi

    2007-01-01

    Full Text Available MicroRNAs (miRNAs are a class of small non-coding RNAs that mediate gene expression at the posttranscriptional and translational levels and have been demonstrated to be involved in diverse biological functions. Mounting evidence in recent years has shown that miRNAs play key roles in tumorigenesis due to abnormal expression of and mutations in miRNAs. High throughput miRNA expression profiling of several major tumor types has identified miRNAs associated with clinical diagnosis and prognosis of cancer treatment. Previously our group has discovered a novel regulatory relationship between tumor suppressor gene p53 with miRNAs expression and a number of miRNA promoters contain putative p53 binding sites. In addition, others have reported that c-myc can mediate a large number of miRNAs expression. In this review, we will emphasize algorithms to identify mRNA targets of miRNAs and the roles of miRNAs in colorectal cancer. In particular, we will discuss a novel regulatory relationship of miRNAs with tumor suppressor p53 and c-myc. miRNAs are becoming promising novel targets and biomarkers for future cancer therapeutic development and clinical molecular diagnosis.

  19. Inhibition of c-Myc by 10058-F4 induces growth arrest and chemosensitivity in pancreatic ductal adenocarcinoma.

    Science.gov (United States)

    Zhang, Meng; Fan, Hai-Yan; Li, Sheng-Chao

    2015-07-01

    Pancreatic ductal adenocarcinoma (PDAC) is a formidable medical challenge due to its malignancies and the absence of effective treatment. c-Myc, as an important transcription factor, plays crucial roles in cell cycle progression, apoptosis and cellular transformation. The c-Myc inhibitor, 10058-F4, has been reported act as a tumor suppressor in several different tumors. In current study, the tumor-suppressive roles of 10058-F4 was observed in human pancreatic cancer cells in vitro as demonstrated by decreased cell viability, cell cycle arrest at the G1/S transition and increased caspase3/7 activity. And tumor responses to gemcitabine were also significantly enhanced by 10058-F4 in PANC-1 and SW1990 cells. In a subcutaneous xenograft model, however, 10058-F4 showed no significant influence on pancreatic tumorigenesis. When combined with gemcitabine, tumorigenesis was drastically attenuated compared with gemcitabine group or 10058-F4 group; this synergistic effect was accompanied with decreased PCNA-positive cells and reduced TUNEL-positive cells in the combined treated group. Subsequent studies revealed that decreased glycolysis may be involved in the inhibitory effect of 10058-F4 on PDAC. Taken together, this study demonstrates the roles of 10058-F4 in PDAC and provides evidence that 10058-F4 in combination with gemcitabine showed significant clinical benefit over the usage of gemcitabine alone. Copyright © 2015. Published by Elsevier Masson SAS.

  20. Synthesis and characterization of polyamidoamine dendrimer-coated multi-walled carbon nanotubes and their application in gene delivery systems

    Science.gov (United States)

    Pan, Bifeng; Cui, Daxiang; Xu, Ping; Ozkan, Cengiz; Feng, Gao; Ozkan, Mihri; Huang, Tuo; Chu, Bingfeng; Li, Qing; He, Rong; Hu, Guohan

    2009-03-01

    With the aim of improving the amount and delivery efficiency of genes taken by carbon nanotubes into human cancer cells, different generations of polyamidoamine dendrimer modified multi-walled carbon nanotubes (dMNTs) were fabricated, and characterized by high-resolution transmission electron microscopy, atomic force microscopy, x-ray photoelectron spectroscopy, Raman spectroscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis, revealing the presence of dendrimer capped on the surface of carbon nanotubes. The dMNTs fully conjugated with FITC-labeled antisense c-myc oligonucleotides (asODN), those resultant asODN-dMNTs composites were incubated with human breast cancer cell line MCF-7 cells and MDA-MB-435 cells, and liver cancer cell line HepG2 cells, and confirmed to enter into tumor cells within 15 min by laser confocal microscopy. These composites inhibited the cell growth in time- and dose-dependent means, and down-regulated the expression of the c-myc gene and C-Myc protein. Compared with the composites of CNT-NH2-asODN and dendrimer-asODN, no. 5 generation of dendrimer-modified MNT-asODN composites exhibit maximal transfection efficiencies and inhibition effects on tumor cells. The intracellular gene transport and uptake via dMNTs should be generic for the mammalian cell lines. The dMNTs have potentials in applications such as gene or drug delivery for cancer therapy and molecular imaging.

  1. Synthesis and characterization of polyamidoamine dendrimer-coated multi-walled carbon nanotubes and their application in gene delivery systems

    Energy Technology Data Exchange (ETDEWEB)

    Pan Bifeng; Cui Daxiang; Xu Ping; Feng Gao; Huang Tuo; Li Qing; He Rong [Department of Bio-Nano-Science and Engineering, National Key Laboratory of Nano/Micro Fabrication Technology, Key Laboratory for Thin Film and Microfabrication of Ministry of Education, Institute of Micro-Nano Science and Technology, Shanghai JiaoTong University, 800 Dongchuan Road, Shanghai 200240 (China); Ozkan, Cengiz [Mechanical Engineering Department, University of California Riverside, 900 University Avenue-Riverside, CA 92521 (United States); Ozkan, Mihri [Electrical Engineering Department, University of California Riverside, 900 University Avenue, Riverside, CA 92521 (United States); Chu, Bingfeng [Department of Stomatology, General Hospital of PLA, 28 Fuxing Road, Beijing100853 (China); Hu Guohan [Department of Neurosurgery of Changzheng Hospital, 415 Fengyang Road, Second Military Medical University, Shanghai 20003 (China)], E-mail: dxcui@sjtu.edu.cn, E-mail: huguohan6504@sina.com

    2009-03-25

    With the aim of improving the amount and delivery efficiency of genes taken by carbon nanotubes into human cancer cells, different generations of polyamidoamine dendrimer modified multi-walled carbon nanotubes (dMNTs) were fabricated, and characterized by high-resolution transmission electron microscopy, atomic force microscopy, x-ray photoelectron spectroscopy, Raman spectroscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis, revealing the presence of dendrimer capped on the surface of carbon nanotubes. The dMNTs fully conjugated with FITC-labeled antisense c-myc oligonucleotides (asODN), those resultant asODN-dMNTs composites were incubated with human breast cancer cell line MCF-7 cells and MDA-MB-435 cells, and liver cancer cell line HepG2 cells, and confirmed to enter into tumor cells within 15 min by laser confocal microscopy. These composites inhibited the cell growth in time- and dose-dependent means, and down-regulated the expression of the c-myc gene and C-Myc protein. Compared with the composites of CNT-NH{sub 2}-asODN and dendrimer-asODN, no. 5 generation of dendrimer-modified MNT-asODN composites exhibit maximal transfection efficiencies and inhibition effects on tumor cells. The intracellular gene transport and uptake via dMNTs should be generic for the mammalian cell lines. The dMNTs have potentials in applications such as gene or drug delivery for cancer therapy and molecular imaging.

  2. Synthesis and characterization of polyamidoamine dendrimer-coated multi-walled carbon nanotubes and their application in gene delivery systems

    International Nuclear Information System (INIS)

    Pan Bifeng; Cui Daxiang; Xu Ping; Feng Gao; Huang Tuo; Li Qing; He Rong; Ozkan, Cengiz; Ozkan, Mihri; Chu, Bingfeng; Hu Guohan

    2009-01-01

    With the aim of improving the amount and delivery efficiency of genes taken by carbon nanotubes into human cancer cells, different generations of polyamidoamine dendrimer modified multi-walled carbon nanotubes (dMNTs) were fabricated, and characterized by high-resolution transmission electron microscopy, atomic force microscopy, x-ray photoelectron spectroscopy, Raman spectroscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis, revealing the presence of dendrimer capped on the surface of carbon nanotubes. The dMNTs fully conjugated with FITC-labeled antisense c-myc oligonucleotides (asODN), those resultant asODN-dMNTs composites were incubated with human breast cancer cell line MCF-7 cells and MDA-MB-435 cells, and liver cancer cell line HepG2 cells, and confirmed to enter into tumor cells within 15 min by laser confocal microscopy. These composites inhibited the cell growth in time- and dose-dependent means, and down-regulated the expression of the c-myc gene and C-Myc protein. Compared with the composites of CNT-NH 2 -asODN and dendrimer-asODN, no. 5 generation of dendrimer-modified MNT-asODN composites exhibit maximal transfection efficiencies and inhibition effects on tumor cells. The intracellular gene transport and uptake via dMNTs should be generic for the mammalian cell lines. The dMNTs have potentials in applications such as gene or drug delivery for cancer therapy and molecular imaging.

  3. SIRT7 Represses Myc Activity to Suppress ER Stress and Prevent Fatty Liver Disease

    Directory of Open Access Journals (Sweden)

    Jiyung Shin

    2013-11-01

    Full Text Available Nonalcoholic fatty liver disease is the most common chronic liver disorder in developed countries. Its pathogenesis is poorly understood, and therapeutic options are limited. Here, we show that SIRT7, an NAD+-dependent H3K18Ac deacetylase, functions at chromatin to suppress ER stress and prevent the development of fatty liver disease. SIRT7 is induced upon ER stress and is stabilized at the promoters of ribosomal proteins through its interaction with the transcription factor Myc to silence gene expression and to relieve ER stress. SIRT7-deficient mice develop chronic hepatosteatosis resembling human fatty liver disease. Myc inactivation or pharmacological suppression of ER stress alleviates fatty liver caused by SIRT7 deficiency. Importantly, SIRT7 suppresses ER stress and reverts the fatty liver disease in diet-induced obese mice. Our study identifies SIRT7 as a cofactor of Myc for transcriptional repression and delineates a druggable regulatory branch of the ER stress response that prevents and reverts fatty liver disease.

  4. An Algorithm for Generating Small RNAs Capable of Epigenetically Modulating Transcriptional Gene Silencing and Activation in Human Cells

    Directory of Open Access Journals (Sweden)

    Amanda Ackley

    2013-01-01

    Full Text Available Small noncoding antisense RNAs (sasRNAs guide epigenetic silencing complexes to target loci in human cells and modulate gene transcription. When these targeted loci are situated within a promoter, long-term, stable epigenetic silencing of transcription can occur. Recent studies suggest that there exists an endogenous form of such epigenetic regulation in human cells involving long noncoding RNAs. In this article, we present and validate an algorithm for the generation of highly effective sasRNAs that can mimic the endogenous noncoding RNAs involved in the epigenetic regulation of gene expression. We validate this algorithm by targeting several oncogenes including AKT-1, c-MYC, K-RAS, and H-RAS. We also target a long antisense RNA that mediates the epigenetic repression of the tumor suppressor gene DUSP6, silenced in pancreatic cancer. An algorithm that can efficiently design small noncoding RNAs for the epigenetic transcriptional silencing or activation of specific genes has potential therapeutic and experimental applications.

  5. Selective activation of human heat shock gene transcription by nitrosourea antitumor drugs mediated by isocyanate-induced damage and activation of heat shock transcription factor.

    Science.gov (United States)

    Kroes, R A; Abravaya, K; Seidenfeld, J; Morimoto, R I

    1991-01-01

    Treatment of cultured human tumor cells with the chloroethylnitrosourea antitumor drug 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) selectively induces transcription and protein synthesis of a subset of the human heat shock or stress-induced genes (HSP90 and HSP70) with little effect on other stress genes or on expression of the c-fos, c-myc, or beta-actin genes. The active component of BCNU and related compounds appears to be the isocyanate moiety that causes carbamoylation of proteins and nucleic acids. Transcriptional activation of the human HSP70 gene by BCNU is dependent on the heat shock element and correlates with the level of heat shock transcription factor and its binding to the heat shock element in vivo. Unlike activation by heat or heavy metals, BCNU-mediated activation is strongly dependent upon new protein synthesis. This suggests that BCNU-induced, isocyanate-mediated damage to newly synthesized protein(s) may be responsible for activation of the heat shock transcription factor and increased transcription of the HSP90 and HSP70 genes. Images PMID:2052560

  6. [Relationship between the expression of beta-cat, cyclin D1 and c-myc and the occurance and biological behavior of pancreatic cancer].

    Science.gov (United States)

    Li, Yu-jun; Ji, Xiang-rui

    2003-06-01

    To study the relationship between the abnormal expression of beta-catenin (beta-cat) and the high expressions of cyclin D1 and c-myc and the occurance, proliferation, infiltration, metastasis and prognosis of pancreatic cancer, and to provide rational basis for the clinical diagnosis and treatment. Immunohistochemical PicTure trade mark was used to examine the expressions of beta-cat, cyclin D1 and c-myc in 47 cases of the cancerous tissue of pancreas, 12 cases of the pancreatic intraepithelial neoplasia and 10 cases of normal tissue of pancreas, respectively. Pancreatic cancer proliferation cell nuclear antigen (PCNA) was also tested as the index of the extent of proliferation of the pancreatic cancer. beta-cat was expressed normally in the 10 cases of the normal pancreatic tissue, while cyclin D1 and c-myc were negative. The expression rates of beta-cat, cyclin D1 and c-myc in the tissues of the pancreatic intraepithelial neoplasia and the pancreatic cancer had no significant difference [6/12 and 68.1% (32/47), 6/12 and 74.5% (35/47), 5/12 and 70.2% (33/47) respectively;P values were all more than 0.05]. The abnormal expression rate of beta-cat was significantly correlated to the metastasis of the pancreatic cancer and the one-year survival rate (both P 0.05). The expression rate of cyclin D1 was correlated with the proliferation of the pancreatic cancer and the extent of differentiation (both P 0.05). The expression rate of c-myc was not correlated with the size, the extent of proliferation, infiltration, metastasis, or one-year survival rate (both P > 0.05), but closely with the proliferation activity of the cancerous tissue of pancreas (P < 0.05). The abnormal expression of beta-cat and the high expressions of cyclin D1 and c-myc had a parallel relationship with the pancreatic intraepithelial neoplasia and pancreatic cancer (both P < 0.05, gamma = 1.000, 0.845, 0.437, 0.452). The abnormal expression of beta-cat activates cyclin D1 and c-myc, and results in the

  7. Myc-nick: a cytoplasmic cleavage product of Myc that promotes alpha-tubulin acetylation and cell differentiation.

    Science.gov (United States)

    Conacci-Sorrell, Maralice; Ngouenet, Celine; Eisenman, Robert N

    2010-08-06

    The Myc oncoprotein family comprises transcription factors that control multiple cellular functions and are widely involved in oncogenesis. Here we report the identification of Myc-nick, a cytoplasmic form of Myc generated by calpain-dependent proteolysis at lysine 298 of full-length Myc. Myc-nick retains conserved Myc box regions but lacks nuclear localization signals and the bHLHZ domain essential for heterodimerization with Max and DNA binding. Myc-nick induces alpha-tubulin acetylation and altered cell morphology by recruiting histone acetyltransferase GCN5 to microtubules. During muscle differentiation, while the levels of full-length Myc diminish, Myc-nick and acetylated alpha-tubulin levels are increased. Ectopic expression of Myc-nick accelerates myoblast fusion, triggers the expression of myogenic markers, and permits Myc-deficient fibroblasts to transdifferentiate in response to MyoD. We propose that the cleavage of Myc by calpain abrogates the transcriptional inhibition of differentiation by full-length Myc and generates Myc-nick, a driver of cytoplasmic reorganization and differentiation. Copyright 2010 Elsevier Inc. All rights reserved.

  8. BRD4-targeted therapy induces Myc-independent cytotoxicity in Gnaq/11-mutatant uveal melanoma cells.

    Science.gov (United States)

    Ambrosini, Grazia; Sawle, Ashley D; Musi, Elgilda; Schwartz, Gary K

    2015-10-20

    Uveal melanoma (UM) is an aggressive intraocular malignancy with limited therapeutic options. Both primary and metastatic UM are characterized by oncogenic mutations in the G-protein alpha subunit q and 11. Furthermore, nearly 40% of UM has amplification of the chromosomal arm 8q and monosomy of chromosome 3, with consequent anomalies of MYC copy number. Chromatin regulators have become attractive targets for cancer therapy. In particular, the bromodomain and extra-terminal (BET) inhibitor JQ1 has shown selective inhibition of c-Myc expression with antiproliferative activity in hematopoietic and solid tumors. Here we provide evidence that JQ1 had cytotoxic activity in UM cell lines carrying Gnaq/11 mutations, while in cells without the mutations had little effects. Using microarray analysis, we identified a large subset of genes modulated by JQ1 involved in the regulation of cell cycle, apoptosis and DNA repair. Further analysis of selected genes determined that the concomitant silencing of Bcl-xL and Rad51 represented the minimal requirement to mimic the apoptotic effects of JQ1 in the mutant cells, independently of c-Myc. In addition, administration of JQ1 to mouse xenograft models of Gnaq-mutant UM resulted in significant inhibition of tumor growth.Collectively, our results define BRD4 targeting as a novel therapeutic intervention against UM with Gnaq/Gna11 mutations.

  9. Roles of p53, MYC and HIF-1 in regulating glycolysis - the seventh hallmark of cancer.

    Science.gov (United States)

    Yeung, S J; Pan, J; Lee, M-H

    2008-12-01

    Despite diversity in genetic events in oncogenesis, cancer cells exhibit a common set of functional characteristics. Otto Warburg discovered that cancer cells have consistently higher rates of glycolysis than normal cells. The underlying mechanisms leading to the Warburg phenomenon include mitochondrial changes, upregulation of rate-limiting enzymes/proteins in glycolysis and intracellular pH regulation, hypoxia-induced switch to anaerobic metabolism, and metabolic reprogramming after loss of p53 function. The regulation of energy metabolism can be traced to a "triad" of transcription factors: c-MYC, HIF-1 and p53. Oncogenetic changes involve a nonrandom set of gene deletions, amplifications and mutations, and many oncogenes and tumor suppressor genes cluster along the signaling pathways that regulate c-MYC, HIF-1 and p53. Glycolysis in cancer cells has clinical implications in cancer diagnosis, treatment and interaction with diabetes mellitus. Many drugs targeting energy metabolism are in development. Future advances in technology may bring about transcriptome and metabolome-guided chemotherapy.

  10. The TLR3/TICAM-1 signal constitutively controls spontaneous polyposis through suppression of c-Myc in Apc Min/+ mice.

    Science.gov (United States)

    Ono, Junya; Shime, Hiroaki; Takaki, Hiromi; Takashima, Ken; Funami, Kenji; Yoshida, Sumito; Takeda, Yohei; Matsumoto, Misako; Kasahara, Masanori; Seya, Tsukasa

    2017-10-17

    Intestinal tumorigenesis is promoted by myeloid differentiation primary response gene 88 (MyD88) activation in response to the components of microbiota in Apc Min/+ mice. Microbiota also contains double-stranded RNA (dsRNA), a ligand for TLR3, which activates the toll-like receptor adaptor molecule 1 (TICAM-1, also known as TRIF) pathway. We established Apc Min/+ Ticam1 -/- mice and their survival was compared to survival of Apc Min/+ Myd88 -/- and wild-type (WT) mice. The properties of polyps were investigated using immunofluorescence staining and RT-PCR analysis. We demonstrate that TICAM-1 is essential for suppression of polyp formation in Apc Min/+ mice. TICAM-1 knockout resulted in shorter survival of mice compared to WT mice or mice with knockout of MyD88 in the Apc Min/+ background. Polyps were more frequently formed in the distal intestine of Apc Min/+ Ticam1 -/- mice than in Apc Min/+ mice. Infiltration of immune cells such as CD11b + and CD8α + cells into the polyps was detected histologically. CD11b and CD8α mRNAs were increased in polyps of Apc Min/+ Ticam1 -/- mice compared to Apc Min/+ mice. Gene expression of inducible nitric oxide synthase (iNOS), interferon (IFN)-γ, CXCL9 and IL-12p40 was increased in polyps of Apc Min/+ Ticam1 -/- mice. mRNA and protein expression of c-Myc, a critical transcription factor for inflammation-associated polyposis, were increased in polyps of Apc Min/+ Ticam1 -/- mice. A Lactobacillus strain producing dsRNA was detected in feces of Apc Min/+ mice. These results imply that the TLR3/TICAM-1 pathway inhibits polyposis through suppression of c-Myc expression and supports long survival in Apc Min/+ mice.

  11. Cyclin E/Cdk2, P/CAF, and E1A regulate the transactivation of the c-myc promoter by FOXM1

    International Nuclear Information System (INIS)

    Wierstra, Inken; Alves, Juergen

    2008-01-01

    FOXM1c transactivates the c-myc promoter by binding directly to its TATA-boxes. The present study demonstrates that the transactivation of the c-myc promoter by FOXM1c is enhanced by the key proliferation signal cyclin E/Cdk2, but repressed by P/CAF and the adenoviral oncoprotein E1A. Furthermore, FOXM1c interacts with the coactivator and histone acetyltransferase P/CAF. This study shows that, on the c-myc-P1 TATA-box, FOXM1c does not function simply as normal transcription factor just binding to an unusual site. Moreover, the inhibitory N-terminus of FOXM1c does not inhibit its transrepression domain or its EDA. Others reported that a cyclin/Cdk-binding LXL-motif of the splice variant FoxM1b is required for its interaction with Cdk2, Cdk1, and p27, its phosphorylation by Cdk1 and its activation by Cdc25B. In contrast, we now demonstrate that this LXL-motif is not required for the activation of FOXM1c by cyclin D1/Cdk4, cyclin E/Cdk and cyclin A/Cdk2 or for the repression of FOXM1c by p27

  12. Transcriptional integration of mitogenic and mechanical signals by Myc and YAP.

    Science.gov (United States)

    Croci, Ottavio; De Fazio, Serena; Biagioni, Francesca; Donato, Elisa; Caganova, Marieta; Curti, Laura; Doni, Mirko; Sberna, Silvia; Aldeghi, Deborah; Biancotto, Chiara; Verrecchia, Alessandro; Olivero, Daniela; Amati, Bruno; Campaner, Stefano

    2017-10-15

    Mammalian cells must integrate environmental cues to determine coherent physiological responses. The transcription factors Myc and YAP-TEAD act downstream from mitogenic signals, with the latter responding also to mechanical cues. Here, we show that these factors coordinately regulate genes required for cell proliferation. Activation of Myc led to extensive association with its genomic targets, most of which were prebound by TEAD. At these loci, recruitment of YAP was Myc-dependent and led to full transcriptional activation. This cooperation was critical for cell cycle entry, organ growth, and tumorigenesis. Thus, Myc and YAP-TEAD integrate mitogenic and mechanical cues at the transcriptional level to provide multifactorial control of cell proliferation. © 2017 Croci et al.; Published by Cold Spring Harbor Laboratory Press.

  13. The cancer-promoting gene fatty acid-binding protein 5 (FABP5) is epigenetically regulated during human prostate carcinogenesis.

    Science.gov (United States)

    Kawaguchi, Koichiro; Kinameri, Ayumi; Suzuki, Shunsuke; Senga, Shogo; Ke, Youqiang; Fujii, Hiroshi

    2016-02-15

    FABPs (fatty-acid-binding proteins) are a family of low-molecular-mass intracellular lipid-binding proteins consisting of ten isoforms. FABPs are involved in binding and storing hydrophobic ligands such as long-chain fatty acids, as well as transporting these ligands to the appropriate compartments in the cell. FABP5 is overexpressed in multiple types of tumours. Furthermore, up-regulation of FABP5 is strongly associated with poor survival in triple-negative breast cancer. However, the mechanisms underlying the specific up-regulation of the FABP5 gene in these cancers remain poorly characterized. In the present study, we determined that FABP5 has a typical CpG island around its promoter region. The DNA methylation status of the CpG island in the FABP5 promoter of benign prostate cells (PNT2), prostate cancer cells (PC-3, DU-145, 22Rv1 and LNCaP) and human normal or tumour tissue was assessed by bisulfite sequencing analysis, and then confirmed by COBRA (combined bisulfite restriction analysis) and qAMP (quantitative analysis of DNA methylation using real-time PCR). These results demonstrated that overexpression of FABP5 in prostate cancer cells can be attributed to hypomethylation of the CpG island in its promoter region, along with up-regulation of the direct trans-acting factors Sp1 (specificity protein 1) and c-Myc. Together, these mechanisms result in the transcriptional activation of FABP5 expression during human prostate carcinogenesis. Importantly, silencing of Sp1, c-Myc or FABP5 expression led to a significant decrease in cell proliferation, indicating that up-regulation of FABP5 expression by Sp1 and c-Myc is critical for the proliferation of prostate cancer cells. © 2016 Authors; published by Portland Press Limited.

  14. Molecular cloning and analysis of Myc modulator 1 (Mm-1 from Bufo gargarizans (Amphibia: Anura

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    Ning Wang

    2010-02-01

    Full Text Available The protein of Myc modulator 1 (Mm-1 has been reported to repress the transcriptional activity of the proto-oncogene c-Myc in humans. Moreover, it was shown to be the subunit 5 of human prefoldin (PFD. So far, this gene and its homologs have been isolated and sequenced in many organisms, such as mammals and fish, but has not been sequenced for any amphibian or reptile. In order to better understand the function and evolution of Mm-1, we isolated a full-length Mm-1 cDNA (BgMm-1, GenBank accession no. EF211947 from Bufo gargarizans (Cantor, 1842 using RACE (rapid amplification of cDNA ends methods. Mm-1 in B. gargarizans is 755 bp long, comprising an open reading frame (ORF of 459 bp encoding 152 amino acids. The amino acid sequence had a prefoldin α-like domain, partially including a typical putative leucine zipper motif. BgMm-1 showed high similarity to its homolog of Mus musculus Linnaeus, 1758 (82% and Homo sapiens Linnaeus, 1758 MM-1 isoform a (81% at the amino acid level. The protein secondary structure modeled with the SWISS MODEL server revealed that there were two α-helices and four b-strands in BgMm-1 as its human orthologue, and both proteins belonged to the a class of PFD family. The phylogenetic relationships of Mm-1s from lower archaea to high mammals was consistent with the evolution of species, meanwhile the cluster result was consistent with the multiple alignment and the sequence identity analysis. RT-PCR (reverse transcriptase-polymerase chain reaction analysis demonstrated that BgMm-1 expressed widely in ten tissues of adult toad. These results can be helpful for the further investigation on the evolution of Mm-1.

  15. Gene expression in skin tumors induced in hairless mice by chronic exposure to ultraviolet B irradiation

    International Nuclear Information System (INIS)

    Sato, Hiromi; Tanaka, Misao; Kobayashi, Shizuko; Suzuki, Junko S.; Ogiso, Manabu; Tohyama, Chiharu

    1997-01-01

    We investigated the expressions of c-Ha-ras, c-jun, c-fos, c-myc genes and p53 protein in the development of skin tumours induced by chronic exposure to UVB without a photosensitizer using hairless mice. When mice were exposed to UVB at a dose of 2 kJ/m 2 three times a week, increased c-Ha-ras and c-myc transcripts were detected after only 5 weeks of exposure, while no tumour appeared on the exposed skin. The increase in gene expression continued until 25 weeks, when tumours, identified pathologically as mainly squamous cell carcinomas (SCC), developed in the dorsal skin. In these SCC, overexpression of c-fos mRNA was also observed along with the increases in c-Ha-ras and c-myc. A single dose of UVB (2 kJ/m 2 ) applied to the backs of hairless mice transiently induced overexpression of the early event genes c-fos, c-jun and c-myc, but not c-Ha-ras, in the exposed area of skin. Accumulation of p53 protein was determined by Western blotting analysis of immunohistochemistry using monoclonal antibodies PAb 240 or 246, which recognize mutant or wide type, respectively. In the SCC, a mutant p53 protein accumulated in the cytoplasm and nucleus. After single-dose irradiation, the increased wild-type p53 protein was observed in the nuclei of epidermal cells. The present results suggest that overexpression of the c-fos, c-myc and c-Ha-ras genes, and the mutational changes in p53 protein might be associated with skin photocarcinogenesis. Moreover, overexpression of the c-Ha-ras and c-myc genes might be an early event in the development of UVB-induced skin tumors in mice. (author)

  16. Effect of JTV1 gene on the proliferation and apoptosis of K562 cells and its mechanism

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    Yan WU

    2011-05-01

    Full Text Available Objective To investigate the effect of tumor-suppressing gene JTV1 on proliferation and apoptosis of leukemic K562 cells,and the changes in apoptosis factors Bcl-2,C-myc and Bax genes.Methods The recombinate vector pcDNA3.1-JTV1,and the empty vector pcDNA3.1 were transfected into K562 cells as control.The cell proliferation of K562 cells was evaluated by colony formation assay;the cell cycle and apoptosis rate were assessed by flow cytometry(FCM;the mRNA levels of apoptosis related genes Bax,Bcl-2 and C-myc were determined by RT-PCR;the protein levels of Bax,Bcl-2 and C-myc were assayed by Western Blotting.Results The colony formation assay showed that the proliferation of K562 cells decreased when the expression of JTV1 gene was up-regulated.FCM assay showed that the G phase cells in pcDNA3.1-JTV1 positive transfection group increased compared with that of the control group and the pcDNA3.1 empty vector transfected group,and the differences were statistically significant(P < 0.05.Compared with the control group and the empty vector group,the mRNA transcription level and the protein translation level of Bax gene increased significantly,and the mRNA transcription level and the protein translation level of Bcl-2 and C-myc gene were reduced significantly(P < 0.05.Conclusions The expressions of Bcl-2 and C-myc gene are inhibited when the gene JTV1 is up-regulated,leading to an increase in Bax gene expression,inhibition of K562 cell proliferation,and promotion of tumor cells apoptosis.Over expression of JTV1 gene can inhibit the proliferation of K562 cells and promote cell apoptosis by inhibiting Bcl-2 and C-myc expression and up-regulating that of Bax.

  17. Integrative annotation of 21,037 human genes validated by full-length cDNA clones.

    Directory of Open Access Journals (Sweden)

    Tadashi Imanishi

    2004-06-01

    Full Text Available The human genome sequence defines our inherent biological potential; the realization of the biology encoded therein requires knowledge of the function of each gene. Currently, our knowledge in this area is still limited. Several lines of investigation have been used to elucidate the structure and function of the genes in the human genome. Even so, gene prediction remains a difficult task, as the varieties of transcripts of a gene may vary to a great extent. We thus performed an exhaustive integrative characterization of 41,118 full-length cDNAs that capture the gene transcripts as complete functional cassettes, providing an unequivocal report of structural and functional diversity at the gene level. Our international collaboration has validated 21,037 human gene candidates by analysis of high-quality full-length cDNA clones through curation using unified criteria. This led to the identification of 5,155 new gene candidates. It also manifested the most reliable way to control the quality of the cDNA clones. We have developed a human gene database, called the H-Invitational Database (H-InvDB; http://www.h-invitational.jp/. It provides the following: integrative annotation of human genes, description of gene structures, details of novel alternative splicing isoforms, non-protein-coding RNAs, functional domains, subcellular localizations, metabolic pathways, predictions of protein three-dimensional structure, mapping of known single nucleotide polymorphisms (SNPs, identification of polymorphic microsatellite repeats within human genes, and comparative results with mouse full-length cDNAs. The H-InvDB analysis has shown that up to 4% of the human genome sequence (National Center for Biotechnology Information build 34 assembly may contain misassembled or missing regions. We found that 6.5% of the human gene candidates (1,377 loci did not have a good protein-coding open reading frame, of which 296 loci are strong candidates for non-protein-coding RNA

  18. Rearrangements of MYC gene facilitate risk stratification in diffuse large B-cell lymphoma patients treated with rituximab-CHOP

    DEFF Research Database (Denmark)

    Tzankov, Alexandar; Xu-Monette, Zijun Y; Gerhard, Marc

    2014-01-01

    In order to address the debatable prognostic role of MYC rearrangements in diffuse large B-cell lymphoma patients treated with rituximab, cyclophosphamide, hydroxydaunorubicin, vincristine, and prednisone, we evaluated MYC rearrangements by fluorescence in situ hybridization in 563 cases using...... with the dual-fusion probes, 15 detectable only with the break-apart probes and 20 detectable with both dual-fusion probes and break-apart probes. MYC rearrangements correlated with germinal center B-cell origin (P=0.02), MYC protein expression (P=0.032), and larger tumor mass size (P=0.0003). Patients with MYC...... was prognostically additive. Radiotherapy seemed to diminish the prognostic effects of MYC rearrangements in diffuse large B-cell lymphoma patients since only 2/10 irradiated patients with MYC rearrangements died of/with disease, compared with 16/28 non-irradiated patients with MYC rearrangements. We conclude...

  19. Human mast cell tryptase: Multiple cDNAs and genes reveal a multigene serine protease family

    International Nuclear Information System (INIS)

    Vanderslice, P.; Ballinger, S.M.; Tam, E.K.; Goldstein, S.M.; Craik, C.S.; Caughey, G.H.

    1990-01-01

    Three different cDNAs and a gene encoding human skin mast cell tryptase have been cloned and sequenced in their entirety. The deduced amino acid sequences reveal a 30-amino acid prepropeptide followed by a 245-amino acid catalytic domain. The C-terminal undecapeptide of the human preprosequence is identical in dog tryptase and appears to be part of a prosequence unique among serine proteases. The differences among the three human tryptase catalytic domains include the loss of a consensus N-glycosylation site in one cDNA, which may explain some of the heterogeneity in size and susceptibility to deglycosylation seen in tryptase preparations. All three tryptase cDNAs are distinct from a recently reported cDNA obtained from a human lung mast cell library. A skin tryptase cDNA was used to isolate a human tryptase gene, the exons of which match one of the skin-derived cDNAs. The organization of the ∼1.8-kilobase-pair tryptase gene is unique and is not closely related to that of any other mast cell or leukocyte serine protease. The 5' regulatory regions of the gene share features with those of other serine proteases, including mast cell chymase, but are unusual in being separated from the protein-coding sequence by an intron. High-stringency hybridization of a human genomic DNA blot with a fragment of the tryptase gene confirms the presence of multiple tryptase genes. These findings provide genetic evidence that human mast cell tryptases are the products of a multigene family

  20. Gene expression of panaxydol-treated human melanoma cells using radioactive cDNA microarrays

    International Nuclear Information System (INIS)

    Cho, Joong Youn; Yu, Su Jin; Soh, Jeong Won; Kim, Meyoung Kon

    2001-01-01

    Polyacetylenic alcohols derived from Panax ginseng have been studied to be an anticancer reagent previously. One of the Panax ginseng polyacetylenic alcohols, i.e., panaxydol, has been studied to possess an antiproliferative effect on human melanoma cell line (SK-MEL-1). In ths study, radioactive cDNA microarrays enabled an efficient approach to analyze the pattern of gene expression (3.194 genes in a total) simultaneously. The bioinformatics selection of human cDNAs, which is specifically designed for immunology, apoptosis and signal transduction, were arrayed on nylon membranes. Using with 33 P labeled probes, this method provided highly sensitive gene expression profiles of our interest including apoptosis, cell proliferation, cell cycle, and signal transduction. Gene expression profiles were also classified into several categories in accordance with the duration of panaxydol treatment. Consequently, the gene profiles of our interest were significantly up (199 genes, > 2.0 of Z-ratio) or down-(196 genes, < 2.0 of Z-ratio) regulated in panaxydol-treated human melanoma cells

  1. Gene expression of panaxydol-treated human melanoma cells using radioactive cDNA microarrays

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Joong Youn; Yu, Su Jin; Soh, Jeong Won; Kim, Meyoung Kon [College of Medicine, Korea Univ., Seoul (Korea, Republic of)

    2001-07-01

    Polyacetylenic alcohols derived from Panax ginseng have been studied to be an anticancer reagent previously. One of the Panax ginseng polyacetylenic alcohols, i.e., panaxydol, has been studied to possess an antiproliferative effect on human melanoma cell line (SK-MEL-1). In ths study, radioactive cDNA microarrays enabled an efficient approach to analyze the pattern of gene expression (3.194 genes in a total) simultaneously. The bioinformatics selection of human cDNAs, which is specifically designed for immunology, apoptosis and signal transduction, were arrayed on nylon membranes. Using with {sup 33}P labeled probes, this method provided highly sensitive gene expression profiles of our interest including apoptosis, cell proliferation, cell cycle, and signal transduction. Gene expression profiles were also classified into several categories in accordance with the duration of panaxydol treatment. Consequently, the gene profiles of our interest were significantly up (199 genes, > 2.0 of Z-ratio) or down-(196 genes, < 2.0 of Z-ratio) regulated in panaxydol-treated human melanoma cells.

  2. N-myc oncogene amplification is correlated to trace metal concentrations in neuroblastoma cultured cells

    International Nuclear Information System (INIS)

    Gouget, B.; Sergeant, C.; Benard, J.; Llabador, Y.; Simonoff, M.

    2000-01-01

    N-myc oncogene amplification is a powerful predictor of aggressive behavior of neuroblastoma (NB), the most common solid tumor of the early childhood. Since N-myc overexpression - subsequent to amplification - determines a phenotype of invasiveness and metastatic spreading, it is assumed that N-myc amplified neuroblasts synthesize zinc metalloenzymes leading to tumor invasion and formation of metastases. In order to test a possible relation between N-myc oncogene amplification and trace metal contents in human NB cells, Fe, Cu and Zn concentrations have been measured by nuclear microprobe analysis in three human neuroblastoma cell lines with various degrees of N-myc amplification. Elemental determinations show uniform distribution of trace metals within the cells, but variations of intracellular trace metal concentrations with respect to the degree of N-myc amplification are highly dependent on the nature of the element. Zinc concentration is higher in both N-myc amplified cell lines (IMR-32 and IGR-N-91) than in the non-amplified cells (SK-N-SH). In contrast, intracellular iron content is particularly low in N-myc amplified cell lines. Moreover, copper concentrations showed an increase with the degree of N-myc amplification. These results indicate that a relationship exists between intracellular trace metals and N-myc oncogene amplification. They further suggest that trace metals very probably play a determinant role in mechanisms of the neuroblastoma invasiveness

  3. Screening of radiation-induced genes in human lymphoblastoid cells irradiated with 20 cGy of γ-ray by gene chip

    International Nuclear Information System (INIS)

    Wang Huiping; Long Xianhui; Xu Qinzhi; Bai Bei; Sui Jianli; Zhou Pingkun

    2006-01-01

    cDNA gene chip was used to detect the transcriptional profile of human lymphoblasts cells irradiated with 20 cGy of 60 Co γ-ray. The microarray contains 14112 cDNA probing corresponding to 14112 human genes. The results showed that the transcription level of 83 genes changed; among which 21 genes were up-regulated. Most of them were associated with signal transduction, cell cycle regulation, cellular immunity, cytoskeleton and movement, etc. It indicated that low-dose irradiation can modulate the expression of a series of functional genes, which is the primary molecular basis of cellular responses to radiation. (authors)

  4. The human T-cell leukemia virus type-1 p30II protein activates p53 and induces the TIGAR and suppresses oncogene-induced oxidative stress during viral carcinogenesis.

    Science.gov (United States)

    Romeo, Megan; Hutchison, Tetiana; Malu, Aditi; White, Averi; Kim, Janice; Gardner, Rachel; Smith, Katie; Nelson, Katherine; Bergeson, Rachel; McKee, Ryan; Harrod, Carolyn; Ratner, Lee; Lüscher, Bernhard; Martinez, Ernest; Harrod, Robert

    2018-05-01

    In normal cells, aberrant oncogene expression leads to the accumulation of cytotoxic metabolites, including reactive oxygen species (ROS), which can cause oxidative DNA-damage and apoptosis as an intrinsic barrier against neoplastic disease. The c-Myc oncoprotein is overexpressed in many lymphoid cancers due to c-myc gene amplification and/or 8q24 chromosomal translocations. Intriguingly, p53 is a downstream target of c-Myc and hematological malignancies, such as adult T-cell leukemia/lymphoma (ATL), frequently contain wildtype p53 and c-Myc overexpression. We therefore hypothesized that p53-regulated pro-survival signals may thwart the cell's metabolic anticancer defenses to support oncogene-activation in lymphoid cancers. Here we show that the Tp53-induced glycolysis and apoptosis regulator (TIGAR) promotes c-myc oncogene-activation by the human T-cell leukemia virus type-1 (HTLV-1) latency-maintenance factor p30 II , associated with c-Myc deregulation in ATL clinical isolates. TIGAR prevents the intracellular accumulation of c-Myc-induced ROS and inhibits oncogene-induced cellular senescence in ATL, acute lymphoblastic leukemia, and multiple myeloma cells with elevated c-Myc expression. Our results allude to a pivotal role for p53-regulated antioxidant signals as mediators of c-Myc oncogenic functions in viral and non-viral lymphoid tumors. Copyright © 2018 Elsevier Inc. All rights reserved.

  5. Parp-1 genetic ablation in Ela-myc mice unveils novel roles for Parp-1 in pancreatic cancer.

    Science.gov (United States)

    Martínez-Bosch, Neus; Iglesias, Mar; Munné-Collado, Jessica; Martínez-Cáceres, Carlos; Moreno, Mireia; Guerra, Carmen; Yélamos, Jose; Navarro, Pilar

    2014-10-01

    Pancreatic cancer has a dismal prognosis and is currently the fourth leading cause of cancer-related death in developed countries. The inhibition of poly(ADP-ribose) polymerase-1 (Parp-1), the major protein responsible for poly(ADP-ribosy)lation in response to DNA damage, has emerged as a promising treatment for several tumour types. Here we aimed to elucidate the involvement of Parp-1 in pancreatic tumour progression. We assessed Parp-1 protein expression in normal, preneoplastic and pancreatic tumour samples from humans and from K-Ras- and c-myc-driven mouse models of pancreatic cancer. Parp-1 was highly expressed in acinar cells in normal and cancer tissues. In contrast, ductal cells expressed very low or undetectable levels of this protein, both in a normal and in a tumour context. The Parp-1 expression pattern was similar in human and mouse samples, thereby validating the use of animal models for further studies. To determine the in vivo effects of Parp-1 depletion on pancreatic cancer progression, Ela-myc-driven pancreatic tumour development was analysed in a Parp-1 knock-out background. Loss of Parp-1 resulted in increased tumour necrosis and decreased proliferation, apoptosis and angiogenesis. Interestingly, Ela-myc:Parp-1(-/-) mice displayed fewer ductal tumours than their Ela-myc:Parp-1(+/+) counterparts, suggesting that Parp-1 participates in promoting acinar-to-ductal metaplasia, a key event in pancreatic cancer initiation. Moreover, impaired macrophage recruitment can be responsible for the ADM blockade found in the Ela-myc:Parp-1(-/-) mice. Finally, molecular analysis revealed that Parp-1 modulates ADM downstream of the Stat3-MMP7 axis and is also involved in transcriptional up-regulation of the MDM2, VEGFR1 and MMP28 cancer-related genes. In conclusion, the expression pattern of Parp-1 in normal and cancer tissue and the in vivo functional effects of Parp-1 depletion point to a novel role for this protein in pancreatic carcinogenesis and shed light

  6. Study on relationship between apoptosis-related genes and radiosensitivity of esophageal squamous cell carcinoma

    International Nuclear Information System (INIS)

    Li Huixiang; Wang Yaohe; Shi Yonggang; Gao Dongling; Zhang Yunhan

    2000-01-01

    Objective: To observing the relationship between apoptosis-related genes bcl-2,c-myc, p53 and the radiosensitivity of esophageal squamous cell carcinoma. Methods: The expression levels of bcl-2, c-myc and p53 genes in 57 biopsy samples from patients of esophageal squamous cell carcinoma were detected with the LSAB immunohistochemistry method. All the patients were treated with radiotherapy. The radiotherapeutic effect in these patients was observed and the relation between gene expression and radiosensitivity was analyzed. Results: Compared with the bcl-2-negative group, the radiosensitivity of bcl-2-positive one was lower(P<0.01). The radiosensitivity of p53-positive group was slightly lower than that of the p53-negative one (P<0.05). The c-myc protein expression was not related to radiosensitivity. Conclusion: Detection and comprehensive analysis of bcl-2, c-myc and p53 protein expressions are useful in forecasting the radiotherapeutic effect on squamous cell carcinoma of esophagus

  7. Loss of MYC confers resistance to doxorubicin-induced apoptosis by preventing the activation of multiple serine protease- and caspase-mediated pathways

    DEFF Research Database (Denmark)

    Grassilli, Emanuela; Ballabeni, Andrea; Maellaro, Emilia

    2004-01-01

    c-Myc plays an essential role in proliferation, differentiation, and apoptosis. Because of its relevance to cancer, most studies have focused on the cellular consequences of c-Myc overexpression. Here, we address the role of physiological levels of c-Myc in drug-induced apoptosis. By using c-MYC ...... support a model in which doxorubicin simultaneously triggers multiple c-Myc-dependent apoptosis pathways....

  8. Focal Adhesion Kinase Is Required for Intestinal Regeneration and Tumorigenesis Downstream of Wnt/c-Myc Signaling

    Science.gov (United States)

    Ashton, Gabrielle H.; Morton, Jennifer P.; Myant, Kevin; Phesse, Toby J.; Ridgway, Rachel A.; Marsh, Victoria; Wilkins, Julie A.; Athineos, Dimitris; Muncan, Vanesa; Kemp, Richard; Neufeld, Kristi; Clevers, Hans; Brunton, Valerie; Winton, Douglas J.; Wang, Xiaoyan; Sears, Rosalie C.; Clarke, Alan R.; Frame, Margaret C.; Sansom, Owen J.

    2012-01-01

    SUMMARY The intestinal epithelium has a remarkable capacity to regenerate after injury and DNA damage. Here, we show that the integrin effector protein Focal Adhesion Kinase (FAK) is dispensable for normal intestinal homeostasis and DNA damage signaling, but is essential for intestinal regeneration following DNA damage. Given Wnt/c-Myc signaling is activated following intestinal regeneration, we investigated the functional importance of FAK following deletion of the Apc tumor suppressor protein within the intestinal epithelium. Following Apc loss, FAK expression increased in a c-Myc-dependent manner. Codeletion of Apc and Fak strongly reduced proliferation normally induced following Apc loss, and this was associated with reduced levels of phospho-Akt and suppression of intestinal tumorigenesis in Apc heterozygous mice. Thus, FAK is required downstream of Wnt Signaling, for Akt/mTOR activation, intestinal regeneration, and tumorigenesis. Importantly, this work suggests that FAK inhibitors may suppress tumorigenesis in patients at high risk of developing colorectal cancer. PMID:20708588

  9. Daily rhythm variations of the clock gene PER1 and cancer-related genes during various stages of carcinogenesis in a golden hamster model of buccal mucosa carcinoma

    Directory of Open Access Journals (Sweden)

    Ye H

    2015-06-01

    Full Text Available Hua Ye, Kai Yang, Xue-Mei Tan, Xiao-Juan Fu, Han-Xue LiDepartment of Oral and Maxillofacial Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People’s Republic of ChinaBackground: Recent studies have demonstrated that the clock gene PER1 regulates various tumor-related genes. Abnormal expressions and circadian rhythm alterations of PER1 are closely related to carcinogenesis. However, the dynamic circadian variations of PER1 and tumor-related genes at different stages of carcinogenesis remain unknown. This study was conducted to investigate the daily rhythm variation of PER1 and expression of tumor-related genes VEGF, KI67, C-MYC, and P53 in different stages of carcinogenesis.Materials and methods: Dimethylbenzanthracene was used to establish a golden hamster model of buccal mucosa carcinogenesis. Hamsters with normal buccal mucosa, precancerous lesion, and cancerous lesion were sacrificed at six different time points during a 24-hour period of a day. Pathological examination was conducted using routine hematoxylin and eosin staining. PER1, VEGF, KI67, C-MYC, and P53 mRNAs were detected by real-time reverse transcriptase polymerase chain reaction, and a cosinor analysis was applied to analyze the daily rhythm.Results: PER1, VEGF, C-MYC, and P53 mRNA exhibited daily rhythmic expression in three carcinogenesis stages, and KI67 mRNA exhibited daily rhythmic expression in the normal and precancerous stages. The daily rhythmic expression of KI67 was not observed in cancerous stages. The mesor and amplitude of PER1 and P53 mRNA expression decreased upon the development of cancer (P<0.05, whereas the mesor and amplitude of VEGF, KI67, and C-MYC mRNA increased upon the development of cancer (P<0.05. Compared with the normal tissues, the acrophases of PER1, VEGF, and C-MYC mRNA occurred earlier, whereas the acrophases of P53 and KI67 mRNA lagged remarkably in the precancerous lesions. In the cancer stage, the acrophases

  10. High levels of nuclear MYC protein predict the presence of MYC rearrangement in diffuse large B-cell lymphoma

    DEFF Research Database (Denmark)

    Green, Tina Marie; Nielsen, Ole; de Stricker, Karin

    2012-01-01

    , and quantitative real-time polymerase chain reaction (QRT-PCR). Overall, 15% of the cases had an MYC break. QRT-PCR analysis of MYC expression showed that 72% of DLBCLs with an MYC break had aberrantly high or low levels of MYC transcript. Excluding the cases with aberrantly low MYC expression, we found...... a significant positive correlation between levels of MYC transcripts and MYC tumor cells; however, QRT-PCR is not readily applicable as a screening tool. Immunohistochemically, all tumors showed a nuclear staining pattern that was simple to evaluate. The percentage of MYC lymphoma cells correlated closely...

  11. Sequence analysis of the MYC oncogene involved in the t(8;14)(q24;q11) chromosome translocation in a human leukemia T-cell line indicates that putative regulatory regions are not altered

    International Nuclear Information System (INIS)

    Finver, S.N.; Nishikura, K.; Finger, L.R.; Haluska, F.G.; Finan, J.; Nowell, P.C.; Croce, C.M.

    1988-01-01

    The authors cloned the translocation-associated and homologous normal MYC alleles from SKW-3, a leukemia T-cell line with the t(8; 14)(q24; q11) translocation, and determined the sequence of the MYC oncogene first exon and flanking 5' putative regulatory regions. S1 nuclease protection experiments utilizing a MYC first exon probe demonstrated transcriptional deregulation of the MYC gene associated with the T-cell receptor α locus on the 8q + chromosome of SKW-3 cells. Nucleotide sequence analysis of the translocation-associated (8q +) MYC allele identified a single base substitution within the upstream flanking region; the homologous nontranslocated allele contained an additional substitution and a two-base deletion. None of the deletions or substitutions localized to putative 5' regulatory regions. The MYC first exon sequence was germ line in both alleles. These results demonstrate that alterations within the putative 5' MYC regulatory regions are not necessarily involved in MYC deregulation in T-cell leukemias, and they show that juxtaposition of the T-cell receptor α locus to a germ-line MYC oncogene results in MYC deregulation

  12. Overexpression of c-myc is associated with adverse clinical features and worse overall survival in multiple myeloma

    DEFF Research Database (Denmark)

    Szabo, Agoston Gyula; Gang, Anne Ortved; Pedersen, Mette Ølgod

    2016-01-01

    The role of c-myc in multiple myeloma (MM) is controversial. We conducted a retrospective study of 117 patients with MM diagnosed between 2004 and 2010 at Herlev Hospital. Immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH) were performed on tissue microarrays (TMAs) made from...

  13. Prognostic impact of concurrent MYC and BCL6 rearrangements and expression in de novo diffuse large B-cell lymphoma

    DEFF Research Database (Denmark)

    Ye, Qing; Xu-Monette, Zijun Y; Tzankov, Alexandar

    2016-01-01

    Double-hit B-cell lymphoma is a common designation for a group of tumors characterized by concurrent translocations of MYC and BCL2, BCL6, or other genes. The prognosis of concurrent MYC and BCL6 translocations is not well known. In this study, we assessed rearrangements and expression of MYC, BCL2...... frequent in activated B-cell like diffuse large B-cell lymphoma). In summary, diffuse large B-cell lymphoma patients with either MYC/BCL6 rearrangements or MYC/BCL6 co-expression did not always have poorer prognosis; MYC expression levels should be evaluated simultaneously; and double-hit B-cell lymphoma...

  14. Concurrent nuclear ERG and MYC protein overexpression defines a subset of locally advanced prostate cancer: Potential opportunities for synergistic targeted therapeutics.

    Science.gov (United States)

    Udager, Aaron M; DeMarzo, Angelo M; Shi, Yang; Hicks, Jessica L; Cao, Xuhong; Siddiqui, Javed; Jiang, Hui; Chinnaiyan, Arul M; Mehra, Rohit

    2016-06-01

    Recurrent ERG gene fusions, the most common genetic alterations in prostate cancer, drive overexpression of the nuclear transcription factor ERG, and are early clonal events in prostate cancer progression. The nuclear transcription factor MYC is also frequently overexpressed in prostate cancer and may play a role in tumor initiation and/or progression. The relationship between nuclear ERG and MYC protein overexpression in prostate cancer, as well as the clinicopathologic characteristics and prognosis of ERG-positive/MYC high tumors, is not well understood. Immunohistochemistry (IHC) for ERG and MYC was performed on formalin-fixed, paraffin-embedded tissue from prostate cancer tissue microarrays (TMAs), and nuclear staining was scored semi-quantitatively (IHC product score range = 0-300). Correlation between nuclear ERG and MYC protein expression and association with clinicopathologic parameters and biochemical recurrence after radical prostatectomy was assessed. 29.1% of all tumor nodules showed concurrent nuclear ERG and MYC protein overexpression (i.e., ERG-positive/MYC high), including 35.0% of secondary nodules. Overall, there was weak positive correlation between ERG and MYC expression across all tumor nodules (rpb  = 0.149, P = 0.045), although this correlation was strongest in secondary nodules (rpb  = 0.520, P = 0.019). In radical prostatectomy specimens, ERG-positive/MYC high tumors were positively associated with the presence of extraprostatic extension (EPE), relative to all other ERG/MYC expression subgroups, however, there was no significant association between concurrent nuclear ERG and MYC protein overexpression and time to biochemical recurrence. Concurrent nuclear ERG and MYC protein overexpression is common in prostate cancer and defines a subset of locally advanced tumors. Recent data indicates that BET bromodomain proteins regulate ERG gene fusion and MYC gene expression in prostate cancer, suggesting possible synergistic

  15. Pan-cancer Alterations of the MYC Oncogene and Its Proximal Network across the Cancer Genome Atlas

    NARCIS (Netherlands)

    Schaub, Franz X.; Dhankani, Varsha; Berger, Ashton C.; Trivedi, Mihir; Richardson, Anne B.; Shaw, Reid; Zhao, Wei; Zhang, Xiaoyang; Ventura, Andrea; Liu, Yuexin; Ayer, Donald E.; Hurlin, Peter J.; Cherniack, Andrew D.; Eisenman, Robert N.; Bernard, Brady; Grandori, Carla; Caesar-Johnson, Samantha J.; Demchok, John A.; Felau, Ina; Kasapi, Melpomeni; Ferguson, Martin L.; Hutter, Carolyn M.; Sofia, Heidi J.; Tarnuzzer, Roy; Wang, Zhining; Yang, Liming; Zenklusen, Jean C.; Zhang, Jiashan (Julia); Chudamani, Sudha; Liu, Jia; Lolla, Laxmi; Naresh, Rashi; Pihl, Todd; Sun, Qiang; Wan, Yunhu; Wu, Ye; Cho, Juok; DeFreitas, Timothy; Frazer, Scott; Gehlenborg, Nils; Getz, Gad; Heiman, David I.; Kim, Jaegil; Lawrence, Michael S.; Lin, Pei; Meier, Sam; Noble, Michael S.; Saksena, Gordon; Voet, Doug; Zhang, Hailei; Bernard, Brady; Chambwe, Nyasha; Dhankani, Varsha; Knijnenburg, Theo; Kramer, Roger; Leinonen, Kalle; Liu, Yuexin; Miller, Michael; Reynolds, Sheila; Shmulevich, Ilya; Thorsson, Vesteinn; Zhang, Wei; Akbani, Rehan; Broom, Bradley M.; Hegde, Apurva M.; Ju, Zhenlin; Kanchi, Rupa S.; Korkut, Anil; Li, Jun; Liang, Han; Ling, Shiyun; Liu, Wenbin; Lu, Yiling; Mills, Gordon B.; Ng, Kwok Shing; Rao, Arvind; Ryan, Michael; Wang, Jing; Weinstein, John N.; Zhang, Jiexin; Abeshouse, Adam; Armenia, Joshua; Chakravarty, Debyani; Chatila, Walid K.; de Bruijn, Ino; Gao, Jianjiong; Gross, Benjamin E.; Heins, Zachary J.; Kundra, Ritika; La, Konnor; Ladanyi, Marc; Luna, Augustin; Nissan, Moriah G.; Ochoa, Angelica; Phillips, Sarah M.; Reznik, Ed; Sanchez-Vega, Francisco; Sander, Chris; Schultz, Nikolaus; Sheridan, Robert; Sumer, S. Onur; Sun, Yichao; Taylor, Barry S.; Wang, Jioajiao; Zhang, Hongxin; Anur, Pavana; Peto, Myron; Spellman, Paul; Benz, Christopher; Stuart, Joshua M.; Wong, Christopher K.; Yau, Christina; Hayes, D. Neil; Parker, Joel S.; Wilkerson, Matthew D.; Ally, Adrian; Balasundaram, Miruna; Bowlby, Reanne; Brooks, Denise; Carlsen, Rebecca; Chuah, Eric; Dhalla, Noreen; Holt, Robert; Jones, Steven J.M.; Kasaian, Katayoon; Lee, Darlene; Ma, Yussanne; Marra, Marco A.; Mayo, Michael; Moore, Richard A.; Mungall, Andrew J.; Mungall, Karen; Robertson, A. Gordon; Sadeghi, Sara; Schein, Jacqueline E.; Sipahimalani, Payal; Tam, Angela; Thiessen, Nina; Tse, Kane; Wong, Tina; Berger, Ashton C.; Beroukhim, Rameen; Cherniack, Andrew D.; Cibulskis, Carrie; Gabriel, Stacey B.; Gao, Galen F.; Ha, Gavin; Meyerson, Matthew; Schumacher, Steven E.; Shih, Juliann; Kucherlapati, Melanie H.; Kucherlapati, Raju S.; Baylin, Stephen; Cope, Leslie; Danilova, Ludmila; Bootwalla, Moiz S.; Lai, Phillip H.; Maglinte, Dennis T.; Van Den Berg, David J.; Weisenberger, Daniel J.; Auman, J. Todd; Balu, Saianand; Bodenheimer, Tom; Fan, Cheng; Hoadley, Katherine A.; Hoyle, Alan P.; Jefferys, Stuart R.; Jones, Corbin D.; Meng, Shaowu; Mieczkowski, Piotr A.; Mose, Lisle E.; Perou, Amy H.; Perou, Charles M.; Roach, Jeffrey; Shi, Yan; Simons, Janae V.; Skelly, Tara; Soloway, Matthew G.; Tan, Donghui; Veluvolu, Umadevi; Fan, Huihui; Hinoue, Toshinori; Laird, Peter W.; Shen, Hui; Zhou, Wanding; Bellair, Michelle; Chang, Kyle; Covington, Kyle; Creighton, Chad J.; Dinh, Huyen; Doddapaneni, Harsha Vardhan; Donehower, Lawrence A.; Drummond, Jennifer; Gibbs, Richard A.; Glenn, Robert; Hale, Walker; Han, Yi; Hu, Jianhong; Korchina, Viktoriya; Lee, Sandra; Lewis, Lora; Li, Wei; Liu, Xiuping; Morgan, Margaret; Morton, Donna; Muzny, Donna; Santibanez, Jireh; Sheth, Margi; Shinbrot, Eve; Wang, Linghua; Wang, Min; Wheeler, David A.; Xi, Liu; Zhao, Fengmei; Hess, Julian; Appelbaum, Elizabeth L.; Bailey, Matthew; Cordes, Matthew G.; Ding, Li; Fronick, Catrina C.; Fulton, Lucinda A.; Fulton, Robert S.; Kandoth, Cyriac; Mardis, Elaine R.; McLellan, Michael D.; Miller, Christopher A.; Schmidt, Heather K.; Wilson, Richard K.; Crain, Daniel; Curley, Erin; Gardner, Johanna; Lau, Kevin; Mallery, David; Morris, Scott; Paulauskis, Joseph; Penny, Robert; Shelton, Candace; Shelton, Troy; Sherman, Mark; Thompson, Eric; Yena, Peggy; Bowen, Jay; Gastier-Foster, Julie M.; Gerken, Mark; Leraas, Kristen M.; Lichtenberg, Tara M.; Ramirez, Nilsa C.; Wise, Lisa; Zmuda, Erik; Corcoran, Niall; Costello, Tony; Hovens, Christopher; Carvalho, Andre L.; de Carvalho, Ana C.; Fregnani, José H.; Longatto-Filho, Adhemar; Reis, Rui M.; Scapulatempo-Neto, Cristovam; Silveira, Henrique C.S.; Vidal, Daniel O.; Burnette, Andrew; Eschbacher, Jennifer; Hermes, Beth; Noss, Ardene; Singh, Rosy; Anderson, Matthew L.; Castro, Patricia D.; Ittmann, Michael; Huntsman, David; Kohl, Bernard; Le, Xuan; Thorp, Richard; Andry, Chris; Duffy, Elizabeth R.; Lyadov, Vladimir; Paklina, Oxana; Setdikova, Galiya; Shabunin, Alexey; Tavobilov, Mikhail; McPherson, Christopher; Warnick, Ronald; Berkowitz, Ross; Cramer, Daniel; Feltmate, Colleen; Horowitz, Neil; Kibel, Adam; Muto, Michael; Raut, Chandrajit P.; Malykh, Andrei; Barnholtz-Sloan, Jill S.; Barrett, Wendi; Devine, Karen; Fulop, Jordonna; Ostrom, Quinn T.; Shimmel, Kristen; Wolinsky, Yingli; Sloan, Andrew E.; De Rose, Agostino; Giuliante, Felice; Goodman, Marc; Karlan, Beth Y.; Hagedorn, Curt H.; Eckman, John; Harr, Jodi; Myers, Jerome; Tucker, Kelinda; Zach, Leigh Anne; Deyarmin, Brenda; Hu, Hai; Kvecher, Leonid; Larson, Caroline; Mural, Richard J.; Somiari, Stella; Vicha, Ales; Zelinka, Tomas; Bennett, Joseph; Iacocca, Mary; Rabeno, Brenda; Swanson, Patricia; Latour, Mathieu; Lacombe, Louis; Têtu, Bernard; Bergeron, Alain; McGraw, Mary; Staugaitis, Susan M.; Chabot, John; Hibshoosh, Hanina; Sepulveda, Antonia; Su, Tao; Wang, Timothy; Potapova, Olga; Voronina, Olga; Desjardins, Laurence; Mariani, Odette; Roman-Roman, Sergio; Sastre, Xavier; Stern, Marc Henri; Cheng, Feixiong; Signoretti, Sabina; Berchuck, Andrew; Bigner, Darell; Lipp, Eric; Marks, Jeffrey; McCall, Shannon; McLendon, Roger; Secord, Angeles; Sharp, Alexis; Behera, Madhusmita; Brat, Daniel J.; Chen, Amy; Delman, Keith; Force, Seth; Khuri, Fadlo; Magliocca, Kelly; Maithel, Shishir; Olson, Jeffrey J.; Owonikoko, Taofeek; Pickens, Alan; Ramalingam, Suresh; Shin, Dong M.; Sica, Gabriel; Van Meir, Erwin G.; Zhang, Hongzheng; Eijckenboom, Wil; Gillis, Ad; Korpershoek, Esther; Looijenga, Leendert; Oosterhuis, Wolter; Stoop, Hans; van Kessel, Kim E.; Zwarthoff, Ellen C.; Calatozzolo, Chiara; Cuppini, Lucia; Cuzzubbo, Stefania; DiMeco, Francesco; Finocchiaro, Gaetano; Mattei, Luca; Perin, Alessandro; Pollo, Bianca; Chen, Chu; Houck, John; Lohavanichbutr, Pawadee; Hartmann, Arndt; Stoehr, Christine; Stoehr, Robert; Taubert, Helge; Wach, Sven; Wullich, Bernd; Kycler, Witold; Murawa, Dawid; Wiznerowicz, Maciej; Chung, Ki; Edenfield, W. Jeffrey; Martin, Julie; Baudin, Eric; Bubley, Glenn; Bueno, Raphael; De Rienzo, Assunta; Richards, William G.; Kalkanis, Steven; Mikkelsen, Tom; Noushmehr, Houtan; Scarpace, Lisa; Girard, Nicolas; Aymerich, Marta; Campo, Elias; Giné, Eva; Guillermo, Armando López; Van Bang, Nguyen; Hanh, Phan Thi; Phu, Bui Duc; Tang, Yufang; Colman, Howard; Evason, Kimberley; Dottino, Peter R.; Martignetti, John A.; Gabra, Hani; Juhl, Hartmut; Akeredolu, Teniola; Stepa, Serghei; Hoon, Dave; Ahn, Keunsoo; Kang, Koo Jeong; Beuschlein, Felix; Breggia, Anne; Birrer, Michael; Bell, Debra; Borad, Mitesh; Bryce, Alan H.; Castle, Erik; Chandan, Vishal; Cheville, John; Copland, John A.; Farnell, Michael; Flotte, Thomas; Giama, Nasra; Ho, Thai; Kendrick, Michael; Kocher, Jean Pierre; Kopp, Karla; Moser, Catherine; Nagorney, David; O'Brien, Daniel; O'Neill, Brian Patrick; Patel, Tushar; Petersen, Gloria; Que, Florencia; Rivera, Michael; Roberts, Lewis; Smallridge, Robert; Smyrk, Thomas; Stanton, Melissa; Thompson, R. Houston; Torbenson, Michael; Yang, Ju Dong; Zhang, Lizhi; Brimo, Fadi; Ajani, Jaffer A.; Angulo Gonzalez, Ana Maria; Behrens, Carmen; Bondaruk, Jolanta; Broaddus, Russell; Czerniak, Bogdan; Esmaeli, Bita; Fujimoto, Junya; Gershenwald, Jeffrey; Guo, Charles; Lazar, Alexander J.; Logothetis, Christopher; Meric-Bernstam, Funda; Moran, Cesar; Ramondetta, Lois; Rice, David; Sood, Anil; Tamboli, Pheroze; Thompson, Timothy; Troncoso, Patricia; Tsao, Anne; Wistuba, Ignacio; Carter, Candace; Haydu, Lauren; Hersey, Peter; Jakrot, Valerie; Kakavand, Hojabr; Kefford, Richard; Lee, Kenneth; Long, Georgina; Mann, Graham; Quinn, Michael; Saw, Robyn; Scolyer, Richard; Shannon, Kerwin; Spillane, Andrew; Stretch, Jonathan; Synott, Maria; Thompson, John; Wilmott, James; Al-Ahmadie, Hikmat; Chan, Timothy A.; Ghossein, Ronald; Gopalan, Anuradha; Levine, Douglas A.; Reuter, Victor; Singer, Samuel; Singh, Bhuvanesh; Tien, Nguyen Viet; Broudy, Thomas; Mirsaidi, Cyrus; Nair, Praveen; Drwiega, Paul; Miller, Judy; Smith, Jennifer; Zaren, Howard; Park, Joong Won; Hung, Nguyen Phi; Kebebew, Electron; Linehan, W. Marston; Metwalli, Adam R.; Pacak, Karel; Pinto, Peter A.; Schiffman, Mark; Schmidt, Laura S.; Vocke, Cathy D.; Wentzensen, Nicolas; Worrell, Robert; Yang, Hannah; Moncrieff, Marc; Goparaju, Chandra; Melamed, Jonathan; Pass, Harvey; Botnariuc, Natalia; Caraman, Irina; Cernat, Mircea; Chemencedji, Inga; Clipca, Adrian; Doruc, Serghei; Gorincioi, Ghenadie; Mura, Sergiu; Pirtac, Maria; Stancul, Irina; Tcaciuc, Diana; Albert, Monique; Alexopoulou, Iakovina; Arnaout, Angel; Bartlett, John; Engel, Jay; Gilbert, Sebastien; Parfitt, Jeremy; Sekhon, Harman; Thomas, George; Rassl, Doris M.; Rintoul, Robert C.; Bifulco, Carlo; Tamakawa, Raina; Urba, Walter; Hayward, Nicholas; Timmers, Henri; Antenucci, Anna; Facciolo, Francesco; Grazi, Gianluca; Marino, Mirella; Merola, Roberta; de Krijger, Ronald; Gimenez-Roqueplo, Anne Paule; Piché, Alain; Chevalier, Simone; McKercher, Ginette; Birsoy, Kivanc; Barnett, Gene; Brewer, Cathy; Farver, Carol; Naska, Theresa; Pennell, Nathan A.; Raymond, Daniel; Schilero, Cathy; Smolenski, Kathy; Williams, Felicia; Morrison, Carl; Borgia, Jeffrey A.; Liptay, Michael J.; Pool, Mark; Seder, Christopher W.; Junker, Kerstin; Omberg, Larsson; Dinkin, Mikhail; Manikhas, George; Alvaro, Domenico; Bragazzi, Maria Consiglia; Cardinale, Vincenzo; Carpino, Guido; Gaudio, Eugenio; Chesla, David; Cottingham, Sandra; Dubina, Michael; Moiseenko, Fedor; Dhanasekaran, Renumathy; Becker, Karl Friedrich; Janssen, Klaus Peter; Slotta-Huspenina, Julia; Abdel-Rahman, Mohamed H.; Aziz, Dina; Bell, Sue; Cebulla, Colleen M.; Davis, Amy; Duell, Rebecca; Elder, J. Bradley; Hilty, Joe; Kumar, Bahavna; Lang, James; Lehman, Norman L.; Mandt, Randy; Nguyen, Phuong; Pilarski, Robert; Rai, Karan; Schoenfield, Lynn; Senecal, Kelly; Wakely, Paul; Hansen, Paul; Lechan, Ronald; Powers, James; Tischler, Arthur; Grizzle, William E.; Sexton, Katherine C.; Kastl, Alison; Henderson, Joel; Porten, Sima; Waldmann, Jens; Fassnacht, Martin; Asa, Sylvia L.; Schadendorf, Dirk; Couce, Marta; Graefen, Markus; Huland, Hartwig; Sauter, Guido; Schlomm, Thorsten; Simon, Ronald; Tennstedt, Pierre; Olabode, Oluwole; Nelson, Mark; Bathe, Oliver; Carroll, Peter R.; Chan, June M.; Disaia, Philip; Glenn, Pat; Kelley, Robin K.; Landen, Charles N.; Phillips, Joanna; Prados, Michael; Simko, Jeffry; Smith-McCune, Karen; VandenBerg, Scott; Roggin, Kevin; Fehrenbach, Ashley; Kendler, Ady; Sifri, Suzanne; Steele, Ruth; Jimeno, Antonio; Carey, Francis; Forgie, Ian; Mannelli, Massimo; Carney, Michael; Hernandez, Brenda; Campos, Benito; Herold-Mende, Christel; Jungk, Christin; Unterberg, Andreas; von Deimling, Andreas; Bossler, Aaron; Galbraith, Joseph; Jacobus, Laura; Knudson, Michael; Knutson, Tina; Ma, Deqin; Milhem, Mohammed; Sigmund, Rita; Godwin, Andrew K.; Madan, Rashna; Rosenthal, Howard G.; Adebamowo, Clement; Adebamowo, Sally N.; Boussioutas, Alex; Beer, David; Giordano, Thomas; Mes-Masson, Anne Marie; Saad, Fred; Bocklage, Therese; Landrum, Lisa; Mannel, Robert; Moore, Kathleen; Moxley, Katherine; Postier, Russel; Walker, Joan; Zuna, Rosemary; Feldman, Michael; Valdivieso, Federico; Dhir, Rajiv; Luketich, James; Mora Pinero, Edna M.; Quintero-Aguilo, Mario; Carlotti, Carlos Gilberto; Dos Santos, Jose Sebastião; Kemp, Rafael; Sankarankuty, Ajith; Tirapelli, Daniela; Catto, James; Agnew, Kathy; Swisher, Elizabeth; Creaney, Jenette; Robinson, Bruce; Shelley, Carl Simon; Godwin, Eryn M.; Kendall, Sara; Shipman, Cassaundra; Bradford, Carol; Carey, Thomas; Haddad, Andrea; Moyer, Jeffey; Peterson, Lisa; Prince, Mark; Rozek, Laura; Wolf, Gregory; Bowman, Rayleen; Fong, Kwun M.; Yang, Ian; Korst, Robert; Rathmell, W. Kimryn; Fantacone-Campbell, J. Leigh; Hooke, Jeffrey A.; Kovatich, Albert J.; Shriver, Craig D.; DiPersio, John; Drake, Bettina; Govindan, Ramaswamy; Heath, Sharon; Ley, Timothy; Van Tine, Brian; Westervelt, Peter; Rubin, Mark A.; Lee, Jung Il; Aredes, Natália D.; Mariamidze, Armaz

    2018-01-01

    Although the MYC oncogene has been implicated in cancer, a systematic assessment of alterations of MYC, related transcription factors, and co-regulatory proteins, forming the proximal MYC network (PMN), across human cancers is lacking. Using computational approaches, we define genomic and proteomic

  16. Characterization of pancreatic lesions from MT-tgf alpha, Ela-myc and MT-tgf alpha/Ela-myc single and double transgenic mice.

    Science.gov (United States)

    Liao, Dezhong Joshua; Wang, Yong; Wu, Jiusheng; Adsay, Nazmi Volkan; Grignon, David; Khanani, Fayyaz; Sarkar, Fazlul H

    2006-07-05

    In order to identify good animal models for investigating therapeutic and preventive strategies for pancreatic cancer, we analyzed pancreatic lesions from several transgenic models and made a series of novel findings. Female MT-tgf alpha mice of the MT100 line developed pancreatic proliferation, acinar-ductal metaplasia, multilocular cystic neoplasms, ductal adenocarcinomas and prominent fibrosis, while the lesions in males were less severe. MT-tgf alpha-ES transgenic lines of both sexes developed slowly progressing lesions that were similar to what was seen in MT100 males. In both MT100 and MT-tgf alpha-ES lines, TGF alpha transgene was expressed mainly in proliferating ductal cells. Ela-myc transgenic mice with a mixed C57BL/6, SJL and FVB genetic background developed pancreatic tumors at 2-7 months of age, and half of the tumors were ductal adenocarcinomas, similar to what was reported originally by Sandgren et al 1. However, in 20% of the mice, the tumors metastasized to the liver. MT100/Ela-myc and MT-tgf alpha-ES/Ela-myc double transgenic mice developed not only acinar carcinomas and mixed carcinomas as previously reported but also various ductal-originated lesions, including multilocular cystic neoplasms and ductal adenocarcinomas. The double transgenic tumors were more malignant and metastasized to the liver at a higher frequency (33%) compared with the Ela-myc tumors. Sequencing of the coding region of p16ink4, k-ras and Rb cDNA in small numbers of pancreatic tumors did not identify mutations. The short latency for tumor development, the variety of tumor morphology and the liver metastases seen in Ela-myc and MT-tgf alpha/Ela-myc mice make these animals good models for investigating new therapeutic and preventive strategies for pancreatic cancer.

  17. Rice MYC2 (OsMYC2) modulates light-dependent seedling ...

    Indian Academy of Sciences (India)

    Mrunmay Kumar Giri

    2017-08-03

    Aug 3, 2017 ... 1School of life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India. 2Department of ... MYC2 orthologues from several crop plants have been characterized. The rice .... AtMYC2 over-expression and mutants were described by us ... The seeds were screened on MS media plates supplemented.

  18. Overexpression of c-myc and loss of heterozigosity on 2p, 3p, 5q, 17p and 18q in sporadic colorectal carcinoma Sobreexpresión de c-myc y pérdida de heterozigosidad en 2p, 3p, 5q, 17p y 18q en carcinoma colorrectal esporádico

    Directory of Open Access Journals (Sweden)

    A. Sánchez-Pernaute

    2005-03-01

    Full Text Available Aim: the aim of the present study is to evaluate the prognostic influence of loss of heterozygosity on 2p, 3p, 5q, 17p and 18q, and c-myc overexpression on surgically treated sporadic colorectal carcinoma. Methods: tumor and non-tumor tissue samples from 153 patients were analyzed. Fifty-one percent of patients were male, and mean age in the series was 67 years. Tumors were located in the proximal colon in 37 cases, in the distal bowel in 37, and in the rectum in 79 patients. c-myc overexpression was studied by means of Northern blot analysis, and loss of heterozigosity through microsatellite analysis. Results: c-myc overexpression was detected in 25% of cases, and loss of heterozygosity in at least one of the studied regions in 48%. There was no association between clinical and pathologic features, and genetic alterations. The disease-free interval was significantly shorter for patients with both genetic alterations; the presence of both events was an independent prognostic factor for poor outcome in the multivariate analysis (RR: 4.34, p Objetivo: el objetivo del presente trabajo es evaluar la importancia pronóstica de la pérdida de heterozigosidad en las regiones 2p, 3p, 5q, 17p y 18q y de la sobreexpresión del gen c-myc en el carcinoma colorrectal esporádico, mediante el estudio de la supervivencia libre de enfermedad tras cirugía potencialmente curativa. Métodos: se han analizado muestras tumorales y no tumorales de mucosa colónica de 153 pacientes. El 51% de los pacientes eran varones y la edad media de la serie fue 67 años. Los tumores fueron proximales en 37 casos, distales en 37 y localizados en recto en 79. Se analizó la sobreexpresión del RNA de c-myc por Northern blot, y la presencia de pérdida de heterozigosidad en las diferentes regiones consideradas por análisis de microsatélites. Resultados: se detectó sobreexpresión de c-myc en el 25% de los casos, y pérdida de heterozigosidad en alguna de las regiones estudiadas

  19. Identification of Candidate B-Lymphoma Genes by Cross-Species Gene Expression Profiling

    Science.gov (United States)

    Tompkins, Van S.; Han, Seong-Su; Olivier, Alicia; Syrbu, Sergei; Bair, Thomas; Button, Anna; Jacobus, Laura; Wang, Zebin; Lifton, Samuel; Raychaudhuri, Pradip; Morse, Herbert C.; Weiner, George; Link, Brian; Smith, Brian J.; Janz, Siegfried

    2013-01-01

    Comparative genome-wide expression profiling of malignant tumor counterparts across the human-mouse species barrier has a successful track record as a gene discovery tool in liver, breast, lung, prostate and other cancers, but has been largely neglected in studies on neoplasms of mature B-lymphocytes such as diffuse large B cell lymphoma (DLBCL) and Burkitt lymphoma (BL). We used global gene expression profiles of DLBCL-like tumors that arose spontaneously in Myc-transgenic C57BL/6 mice as a phylogenetically conserved filter for analyzing the human DLBCL transcriptome. The human and mouse lymphomas were found to have 60 concordantly deregulated genes in common, including 8 genes that Cox hazard regression analysis associated with overall survival in a published landmark dataset of DLBCL. Genetic network analysis of the 60 genes followed by biological validation studies indicate FOXM1 as a candidate DLBCL and BL gene, supporting a number of studies contending that FOXM1 is a therapeutic target in mature B cell tumors. Our findings demonstrate the value of the “mouse filter” for genomic studies of human B-lineage neoplasms for which a vast knowledge base already exists. PMID:24130802

  20. Angiotensin II reduces cardiac AdipoR1 expression through AT1 receptor/ROS/ERK1/2/c-Myc pathway.

    Directory of Open Access Journals (Sweden)

    Li Li

    Full Text Available Adiponectin, an abundant adipose tissue-derived protein, exerts protective effect against cardiovascular disease. Adiponectin receptors (AdipoR1 and AdipoR2 mediate the beneficial effects of adiponectin on the cardiovascular system. However, the alteration of AdipoRs in cardiac remodeling is not fully elucidated. Here, we investigated the effect of angiotensin II (AngII on cardiac AdipoRs expression and explored the possible molecular mechanism. AngII infusion into rats induced cardiac hypertrophy, reduced AdipoR1 but not AdipoR2 expression, and attenuated the phosphorylations of adenosine monophosphate-activated protein kinase and acetyl coenzyme A carboxylase, and those effects were all reversed by losartan, an AngII type 1 (AT1 receptor blocker. AngII reduced expression of AdipoR1 mRNA and protein in cultured neonatal rat cardiomyocytes, which was abolished by losartan, but not by PD123319, an AT2 receptor antagonist. The antioxidants including reactive oxygen species (ROS scavenger NAC, NADPH oxidase inhibitor apocynin, Nox2 inhibitor peptide gp91 ds-tat, and mitochondrial electron transport chain complex I inhibitor rotenone attenuated AngII-induced production of ROS and phosphorylation of extracellular signal-regulated kinase (ERK 1/2. AngII-reduced AdipoR1 expression was reversed by pretreatment with NAC, apocynin, gp91 ds-tat, rotenone, and an ERK1/2 inhibitor PD98059. Chromatin immunoprecipitation assay demonstrated that AngII provoked the recruitment of c-Myc onto the promoter region of AdipoR1, which was attenuated by PD98059. Moreover, AngII-induced DNA binding activity of c-Myc was inhibited by losartan, NAC, apocynin, gp91 ds-tat, rotenone, and PD98059. c-Myc small interfering RNA abolished the inhibitory effect of AngII on AdipoR1 expression. Our results suggest that AngII inhibits cardiac AdipoR1 expression in vivo and in vitro and AT1 receptor/ROS/ERK1/2/c-Myc pathway is required for the downregulation of AdipoR1 induced by AngII.

  1. BET bromodomain inhibition of MYC-amplified medulloblastoma.

    Science.gov (United States)

    Bandopadhayay, Pratiti; Bergthold, Guillaume; Nguyen, Brian; Schubert, Simone; Gholamin, Sharareh; Tang, Yujie; Bolin, Sara; Schumacher, Steven E; Zeid, Rhamy; Masoud, Sabran; Yu, Furong; Vue, Nujsaubnusi; Gibson, William J; Paolella, Brenton R; Mitra, Siddhartha S; Cheshier, Samuel H; Qi, Jun; Liu, Kun-Wei; Wechsler-Reya, Robert; Weiss, William A; Swartling, Fredrik J; Kieran, Mark W; Bradner, James E; Beroukhim, Rameen; Cho, Yoon-Jae

    2014-02-15

    MYC-amplified medulloblastomas are highly lethal tumors. Bromodomain and extraterminal (BET) bromodomain inhibition has recently been shown to suppress MYC-associated transcriptional activity in other cancers. The compound JQ1 inhibits BET bromodomain-containing proteins, including BRD4. Here, we investigate BET bromodomain targeting for the treatment of MYC-amplified medulloblastoma. We evaluated the effects of genetic and pharmacologic inhibition of BET bromodomains on proliferation, cell cycle, and apoptosis in established and newly generated patient- and genetically engineered mouse model (GEMM)-derived medulloblastoma cell lines and xenografts that harbored amplifications of MYC or MYCN. We also assessed the effect of JQ1 on MYC expression and global MYC-associated transcriptional activity. We assessed the in vivo efficacy of JQ1 in orthotopic xenografts established in immunocompromised mice. Treatment of MYC-amplified medulloblastoma cells with JQ1 decreased cell viability associated with arrest at G1 and apoptosis. We observed downregulation of MYC expression and confirmed the inhibition of MYC-associated transcriptional targets. The exogenous expression of MYC from a retroviral promoter reduced the effect of JQ1 on cell viability, suggesting that attenuated levels of MYC contribute to the functional effects of JQ1. JQ1 significantly prolonged the survival of orthotopic xenograft models of MYC-amplified medulloblastoma (P < 0.001). Xenografts harvested from mice after five doses of JQ1 had reduced the expression of MYC mRNA and a reduced proliferative index. JQ1 suppresses MYC expression and MYC-associated transcriptional activity in medulloblastomas, resulting in an overall decrease in medulloblastoma cell viability. These preclinical findings highlight the promise of BET bromodomain inhibitors as novel agents for MYC-amplified medulloblastoma. ©2013 AACR

  2. The Phosphoinositide 3-Kinase p110α Isoform Regulates Leukemia Inhibitory Factor Receptor Expression via c-Myc and miR-125b to Promote Cell Proliferation in Medulloblastoma.

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    Fabiana Salm

    Full Text Available Medulloblastoma (MB is the most common malignant brain tumor in childhood and represents the main cause of cancer-related death in this age group. The phosphoinositide 3-kinase (PI3K pathway has been shown to play an important role in the regulation of medulloblastoma cell survival and proliferation, but the molecular mechanisms and downstream effectors underlying PI3K signaling still remain elusive. The impact of RNA interference (RNAi-mediated silencing of PI3K isoforms p110α and p110δ on global gene expression was investigated by DNA microarray analysis in medulloblastoma cell lines. A subset of genes with selectively altered expression upon p110α silencing in comparison to silencing of the closely related p110δ isoform was revealed. Among these genes, the leukemia inhibitory factor receptor α (LIFR α was validated as a novel p110α target in medulloblastoma. A network involving c-Myc and miR-125b was shown to be involved in the control of LIFRα expression downstream of p110α. Targeting the LIFRα by RNAi, or by using neutralizing reagents impaired medulloblastoma cell proliferation in vitro and induced a tumor volume reduction in vivo. An analysis of primary tumors revealed that LIFRα and p110α expression were elevated in the sonic hedgehog (SHH subgroup of medulloblastoma, indicating its clinical relevance. Together, these data reveal a novel molecular signaling network, in which PI3K isoform p110α controls the expression of LIFRα via c-Myc and miR-125b to promote MB cell proliferation.

  3. Real-time PCR quantification of human complement C4A and C4B genes

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    Fust George

    2006-01-01

    Full Text Available Abstract Background The fourth component of human complement (C4, an essential factor of the innate immunity, is represented as two isoforms (C4A and C4B in the genome. Although these genes differ only in 5 nucleotides, the encoded C4A and C4B proteins are functionally different. Based on phenotypic determination, unbalanced production of C4A and C4B is associated with several diseases, such as systemic lupus erythematosus, type 1 diabetes, several autoimmune diseases, moreover with higher morbidity and mortality of myocardial infarction and increased susceptibility for bacterial infections. Despite of this major clinical relevance, only low throughput, time and labor intensive methods have been used so far for the quantification of C4A and C4B genes. Results A novel quantitative real-time PCR (qPCR technique was developed for rapid and accurate quantification of the C4A and C4B genes applying a duplex, TaqMan based methodology. The reliable, single-step analysis provides the determination of the copy number of the C4A and C4B genes applying a wide range of DNA template concentration (0.3–300 ng genomic DNA. The developed qPCR was applied to determine C4A and C4B gene dosages in a healthy Hungarian population (N = 118. The obtained data were compared to the results of an earlier study of the same population. Moreover a set of 33 samples were analyzed by two independent methods. No significant difference was observed between the gene dosages determined by the employed techniques demonstrating the reliability of the novel qPCR methodology. A Microsoft Excel worksheet and a DOS executable are also provided for simple and automated evaluation of the measured data. Conclusion This report describes a novel real-time PCR method for single-step quantification of C4A and C4B genes. The developed technique could facilitate studies investigating disease association of different C4 isotypes.

  4. Oncogenic MYC Activates a Feedforward Regulatory Loop Promoting Essential Amino Acid Metabolism and Tumorigenesis.

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    Yue, Ming; Jiang, Jue; Gao, Peng; Liu, Hudan; Qing, Guoliang

    2017-12-26

    Most tumor cells exhibit obligatory demands for essential amino acids (EAAs), but the regulatory mechanisms whereby tumor cells take up EAAs and EAAs promote malignant transformation remain to be determined. Here, we show that oncogenic MYC, solute carrier family (SLC) 7 member 5 (SLC7A5), and SLC43A1 constitute a feedforward activation loop to promote EAA transport and tumorigenesis. MYC selectively activates Slc7a5 and Slc43a1 transcription through direct binding to specific E box elements within both genes, enabling effective EAA import. Elevated EAAs, in turn, stimulate Myc mRNA translation, in part through attenuation of the GCN2-eIF2α-ATF4 amino acid stress response pathway, leading to MYC-dependent transcriptional amplification. SLC7A5/SLC43A1 depletion inhibits MYC expression, metabolic reprogramming, and tumor cell growth in vitro and in vivo. These findings thus reveal a MYC-SLC7A5/SLC43A1 signaling circuit that underlies EAA metabolism, MYC deregulation, and tumorigenesis. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  5. Inhibition of bromodomain and extra-terminal (BET) proteins increases NKG2D ligand MICA expression and sensitivity to NK cell-mediated cytotoxicity in multiple myeloma cells: role of cMYC-IRF4-miR-125b interplay.

    Science.gov (United States)

    Abruzzese, Maria Pia; Bilotta, Maria Teresa; Fionda, Cinzia; Zingoni, Alessandra; Soriani, Alessandra; Vulpis, Elisabetta; Borrelli, Cristiana; Zitti, Beatrice; Petrucci, Maria Teresa; Ricciardi, Maria Rosaria; Molfetta, Rosa; Paolini, Rossella; Santoni, Angela; Cippitelli, Marco

    2016-12-01

    Anti-cancer immune responses may contribute to the control of tumors after conventional chemotherapy, and different observations have indicated that chemotherapeutic agents can induce immune responses resulting in cancer cell death and immune-stimulatory side effects. Increasing experimental and clinical evidence highlight the importance of natural killer (NK) cells in immune responses toward multiple myeloma (MM), and combination therapies able to enhance the activity of NK cells against MM are showing promise in treating this hematologic cancer. The epigenetic readers of acetylated histones bromodomain and extra-terminal (BET) proteins are critical regulators of gene expression. In cancer, they can upregulate transcription of key oncogenes such as cMYC, IRF4, and BCL-2. In addition, the activity of these proteins can regulate the expression of osteoclastogenic cytokines during cancer progression. Here, we investigated the effect of BET bromodomain protein inhibition, on the expression of NK cell-activating ligands in MM cells. Five MM cell lines [SKO-007(J3), U266, RPMI-8226, ARP-1, JJN3] and CD138 + MM cells isolated from MM patients were used to investigate the activity of BET bromodomain inhibitors (BETi) (JQ1 and I-BET151) and of the selective BRD4-degrader proteolysis targeting chimera (PROTAC) (ARV-825), on the expression and function of several NK cell-activating ligands (NKG2DLs and DNAM-1Ls), using flow cytometry, real-time PCR, transient transfections, and degranulation assays. Our results indicate that inhibition of BET proteins via small molecule inhibitors or their degradation via a hetero-bifunctional PROTAC probe can enhance the expression of MICA, a ligand of the NKG2D receptor, in human MM cell lines and primary malignant plasma cells, rendering myeloma cells more efficient to activate NK cell degranulation. Noteworthy, similar results were obtained using selective CBP/EP300 bromodomain inhibition. Mechanistically, we found that BETi

  6. RFLP for the human pepsinogen C gene (PGC)

    Energy Technology Data Exchange (ETDEWEB)

    Azuma, T; Pals, G; Taggart, R T

    1988-10-11

    PGC 301 is a 1224 bp cDNA clone containing exons 2-9 of the human pepsinogen C (progastericsin) coding sequence. 100 bp deletion/insertion polymorphism is observed with five restriction endonucleases; BamHI, EcoRI, MstII, PstI, and SacI. The same RFLP is observed with these enzymes. The polymorphic region is located between exons 7 and 8. The frequency was estimated from 40 unrelated Caucasians, with the large fragment allele 82.5% and the small fragment allele 17.5%. PGC gene has been assigned to 6p21.1-pter by somatic cell hybrids. Mendelian inheritance was demonstrated in two families.

  7. Apoptosis and cell proliferation in the development of gastric carcinomas: associations with c-myc and p53 protein expression.

    Science.gov (United States)

    Ishii, Hideaki H; Gobé, Glenda C; Pan, Wenshen; Yoneyama, Juichi; Ebihara, Yoshiro

    2002-09-01

    Patients with gastric carcinomas have a poor prognosis and low survival rates. The aim of the present paper was to characterize cellular and molecular properties to provide insight into aspects of tumor progression in early compared with advanced gastric cancers. One hundred and nine graded gastric carcinomas (early or advanced stage, undifferentiated or differentiated type) with paired non-cancer tissue were studied to define the correlation between apoptosis (morphology, terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labeling), cell proliferation (Ki-67 expression, morphology) and expression and localization of two proteins frequently having altered expression in cancers, namely p53 and c-myc. Overall, apoptosis was lower in early stage, differentiated and undifferentiated gastric carcinomas compared with advanced-stage cancers. Cell proliferation was comparatively high in all stages. There was a high level of p53 positivity in all stages. Only the early- and advanced-stage undifferentiated cancers that were p53 positive had a significantly higher level of apoptosis (P cancers that had either c-myc or p53-positivity. The results indicate that low apoptosis and high cell proliferation combine to drive gastric cancer development. The molecular controls for high cell proliferation of the early stage undifferentiated gastric cancers involve overexpression of both p53 and c-myc. Overexpression of p53 may also control cancer development in that its expression is associated with higher levels of apoptosis in early and late-stage undifferentiated, cancers. Copyright 2002 Blackwell Publishing Asia Pty Ltd

  8. PIAS1 Promotes Lymphomagenesis through MYC Upregulation

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    Andrea Rabellino

    2016-06-01

    Full Text Available The MYC proto-oncogene is a transcription factor implicated in a broad range of cancers. MYC is regulated by several post-translational modifications including SUMOylation, but the functional impact of this post-translational modification is still unclear. Here, we report that the SUMO E3 ligase PIAS1 SUMOylates MYC. We demonstrate that PIAS1 promotes, in a SUMOylation-dependent manner, MYC phosphorylation at serine 62 and dephosphorylation at threonine 58. These events reduce the MYC turnover, leading to increased transcriptional activity. Furthermore, we find that MYC is SUMOylated in primary B cell lymphomas and that PIAS1 is required for the viability of MYC-dependent B cell lymphoma cells as well as several cancer cell lines of epithelial origin. Finally, Pias1-null mice display endothelial defects reminiscent of Myc-null mice. Taken together, these results indicate that PIAS1 is a positive regulator of MYC.

  9. MYC activates stem-like cell potential in hepatocarcinoma by a p53-dependent mechanism

    DEFF Research Database (Denmark)

    Akita, Hirofumi; Marquardt, Jens U; Durkin, Marian E

    2014-01-01

    Activation of c-MYC is an oncogenic hallmark of many cancers including liver cancer, and is associated with a variety of adverse prognostic characteristics. Despite a causative role during malignant transformation and progression in hepatocarcinogenesis, consequences of c-MYC activation for the b...

  10. Human genes for complement components C1r and C1s in a close tail-to-tail arrangement

    International Nuclear Information System (INIS)

    Kusumoto, H.; Hirosawa, S.; Salier, J.P.; Hagen, F.S.; Kurachi, K.

    1988-01-01

    Complementary DNA clones for human C1s were isolated from cDNA libraries that were prepared with poly(A) + RNAs of human liver and HepG2 cells. A clone with the largest cDNA insert of 2,664 base pairs (bp) was analyzed for its complete nucleotide sequence. It contained 202 bp of a 5' untranslated region, 45 bp of coding for a signal peptide (15 amino acid residues), 2,019 bp for complement component C1s zymogen (673 amino acid residues), 378 bp for a 3' untranslated region, a stop codon, and 17 bp of a poly(A) tail. The amino acid sequence of C1s was 40.5% identical to that of C1r, with excellent matches of tentative disulfide bond locations conserving the overall domain structure of C1r. DNA blotting and sequencing analyses of genomic DNA and of an isolated genomic DNA clone clearly showed that the human genes for C1r and C1s are closely located in a tail-to-tail arrangement at a distance of about 9.5 kilobases. Furthermore, RNA blot analyses showed that both C1r and C1s genes are primarily expressed in liver, whereas most other tissues expressed both C1r and C1s genes at much lower levels (less than 10% of that in liver). Multiple molecular sizes of specific mRNAs were observed in the RNA blot analyses for both C1r and C1s, indicating that alternative RNA processing(s), likely an alternative polyadenylylation, might take place for both genes

  11. BIM is the primary mediator of MYC-induced apoptosis in multiple solid tissues.

    Science.gov (United States)

    Muthalagu, Nathiya; Junttila, Melissa R; Wiese, Katrin E; Wolf, Elmar; Morton, Jennifer; Bauer, Barbara; Evan, Gerard I; Eilers, Martin; Murphy, Daniel J

    2014-09-11

    MYC is one of the most frequently overexpressed oncogenes in human cancer, and even modestly deregulated MYC can initiate ectopic proliferation in many postmitotic cell types in vivo. Sensitization of cells to apoptosis limits MYC's oncogenic potential. However, the mechanism through which MYC induces apoptosis is controversial. Some studies implicate p19ARF-mediated stabilization of p53, followed by induction of proapoptotic BH3 proteins NOXA and PUMA, whereas others argue for direct regulation of BH3 proteins, especially BIM. Here, we use a single experimental system to systematically evaluate the roles of p19ARF and BIM during MYC-induced apoptosis, in vitro, in vivo, and in combination with a widely used chemotherapeutic, doxorubicin. We find a common specific requirement for BIM during MYC-induced apoptosis in multiple settings, which does not extend to the p53-responsive BH3 family member PUMA, and find no evidence of a role for p19ARF during MYC-induced apoptosis in the tissues examined. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  12. miR-24 inhibits cell proliferation by suppressing expression of E2F2, MYC and other cell cycle regulatory genes by binding to “seedless” 3′UTR microRNA recognition elements

    Science.gov (United States)

    Lal, Ashish; Navarro, Francisco; Maher, Christopher; Maliszewski, Laura E.; Yan, Nan; O'Day, Elizabeth; Chowdhury, Dipanjan; Dykxhoorn, Derek M.; Tsai, Perry; Hofman, Oliver; Becker, Kevin G.; Gorospe, Myriam; Hide, Winston; Lieberman, Judy

    2009-01-01

    Summary miR-24, up-regulated during terminal differentiation of multiple lineages, inhibits cell cycle progression. Antagonizing miR-24 restores post-mitotic cell proliferation and enhances fibroblast proliferation, while over-expressing miR-24 increases the G1 compartment. The 248 mRNAs down-regulated upon miR-24 over-expression are highly enriched for DNA repair and cell cycle regulatory genes that form a direct interaction network with prominent nodes at genes that enhance (MYC, E2F2, CCNB1, CDC2) or inhibit (p27Kip1, VHL) cell cycle progression. miR-24 directly regulates MYC and E2F2 and some genes they transactivate. Enhanced proliferation from antagonizing miR-24 is abrogated by knocking down E2F2, but not MYC, and cell proliferation, inhibited by miR-24 over-expression, is rescued by miR-24-insensitive E2F2. Therefore, E2F2 is a critical miR-24 target. The E2F2 3′UTR lacks a predicted miR-24 recognition element. In fact, miR-24 regulates expression of E2F2, MYC, AURKB, CCNA2, CDC2, CDK4 and FEN1 by recognizing seedless, but highly complementary, sequences. PMID:19748357

  13. Sequence-specific DNA binding by MYC/MAX to low-affinity non-E-box motifs.

    Directory of Open Access Journals (Sweden)

    Michael Allevato

    Full Text Available The MYC oncoprotein regulates transcription of a large fraction of the genome as an obligatory heterodimer with the transcription factor MAX. The MYC:MAX heterodimer and MAX:MAX homodimer (hereafter MYC/MAX bind Enhancer box (E-box DNA elements (CANNTG and have the greatest affinity for the canonical MYC E-box (CME CACGTG. However, MYC:MAX also recognizes E-box variants and was reported to bind DNA in a "non-specific" fashion in vitro and in vivo. Here, in order to identify potential additional non-canonical binding sites for MYC/MAX, we employed high throughput in vitro protein-binding microarrays, along with electrophoretic mobility-shift assays and bioinformatic analyses of MYC-bound genomic loci in vivo. We identified all hexameric motifs preferentially bound by MYC/MAX in vitro, which include the low-affinity non-E-box sequence AACGTT, and found that the vast majority (87% of MYC-bound genomic sites in a human B cell line contain at least one of the top 21 motifs bound by MYC:MAX in vitro. We further show that high MYC/MAX concentrations are needed for specific binding to the low-affinity sequence AACGTT in vitro and that elevated MYC levels in vivo more markedly increase the occupancy of AACGTT sites relative to CME sites, especially at distal intergenic and intragenic loci. Hence, MYC binds diverse DNA motifs with a broad range of affinities in a sequence-specific and dose-dependent manner, suggesting that MYC overexpression has more selective effects on the tumor transcriptome than previously thought.

  14. Study of differential gene expression in human hepatocyte exposed to 50 cGy γ ray

    International Nuclear Information System (INIS)

    Wen Jianhua; Li Jianguo; Tian Huancheng; Li Yanling; Wang Xiaoli; Zuo Yanhui

    2008-01-01

    The study analyzed the differential transcriptional profile of the normal human hepatic cell and the human hepatic cell radiated with 50 cGy γ ray by gene chip technique. The results showed that there were 614 differentially expressed genes among 14 112 human genes analyzed, in which 521 genes were up-regulated and 93 genes down-regulated. These genes are associated with mitochondrial regulation, homo sapiens hepatitis A virus cellular receptor, tumor necrosis factor, cell cycle regulation, kinase and zinc finger protein etc. RT-PCR results indicated that up-regulated expression of gene HAVcr-1, HAVcr-2, MFTC, MOAP1 and down-regulated expression of gene TRIP12, DCN were consistent with gene chip data. (authors)

  15. Low Dose Radiation Response Curves, Networks and Pathways in Human Lymphoblastoid Cells Exposed from 1 to 10 cGy of Acute Gamma Radiation

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    Wyrobek, A. J.; Manohar, C. F.; Nelson, D. O.; Furtado, M. R.; Bhattacharya, M. S.; Marchetti, F.; Coleman, M.A.

    2011-04-18

    We investigated the low dose dependency of the transcriptional response of human cells to characterize the shape and biological functions associated with the dose response curve and to identify common and conserved functions of low dose expressed genes across cells and tissues. Human lymphoblastoid (HL) cells from two unrelated individuals were exposed to graded doses of radiation spanning the range of 1-10 cGy were analyzed by transcriptome profiling, qPCR and bioinformatics, in comparison to sham irradiated samples. A set of {approx}80 genes showed consistent responses in both cell lines; these genes were associated with homeostasis mechanisms (e.g., membrane signaling, molecule transport), subcellular locations (e.g., Golgi, and endoplasmic reticulum), and involved diverse signal transduction pathways. The majority of radiation-modulated genes had plateau-like responses across 1-10 cGy, some with suggestive evidence that transcription was modulated at doses below 1 cGy. MYC, FOS and TP53 were the major network nodes of the low-dose response in HL cells. Comparison our low dose expression findings in HL cells with those of prior studies in mouse brain after whole body exposure, in human keratinocyte cultures, and in endothelial cells cultures, indicates that certain components of the low dose radiation response are broadly conserved across cell types and tissues, independent of proliferation status.

  16. NDRG2 gene copy number is not altered in colorectal carcinoma

    DEFF Research Database (Denmark)

    Lorentzen, Anders Blomkild; Mitchelmore, Cathy

    2017-01-01

    AIM To investigate if the down-regulation of N-myc Downstream Regulated Gene 2 (NDRG2) expression in colorectal carcinoma (CRC) is due to loss of the NDRG2 allele(s). METHODS The following were investigated in the human colorectal cancer cell lines DLD-1, LoVo and SW-480: NDRG2 mRNA expression...... levels using quantitative reverse transcription-polymerase chain reaction (qRT-PCR); interaction of the MYC gene-regulatory protein with the NDRG2 promoter using chromatin immunoprecipitation; and NDRG2 promoter methylation using bisulfite sequencing. Furthermore, we performed qPCR to analyse the copy...... numbers of NDRG2 and MYC genes in the above three cell lines, 8 normal colorectal tissue samples and 40 CRC tissue samples. RESULTS As expected, NDRG2 mRNA levels were low in the three colorectal cancer cell lines, compared to normal colon. Endogenous MYC protein interacted with the NDRG2 core promoter...

  17. Gene amplification in carcinogenesis

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    Lucimari Bizari

    2006-01-01

    Full Text Available Gene amplification increases the number of genes in a genome and can give rise to karyotype abnormalities called double minutes (DM and homogeneously staining regions (HSR, both of which have been widely observed in human tumors but are also known to play a major role during embryonic development due to the fact that they are responsible for the programmed increase of gene expression. The etiology of gene amplification during carcinogenesis is not yet completely understood but can be considered a result of genetic instability. Gene amplification leads to an increase in protein expression and provides a selective advantage during cell growth. Oncogenes such as CCND1, c-MET, c-MYC, ERBB2, EGFR and MDM2 are amplified in human tumors and can be associated with increased expression of their respective proteins or not. In general, gene amplification is associated with more aggressive tumors, metastases, resistance to chemotherapy and a decrease in the period during which the patient stays free of the disease. This review discusses the major role of gene amplification in the progression of carcinomas, formation of genetic markers and as possible therapeutic targets for the development of drugs for the treatment of some types of tumors.

  18. dMyc functions downstream of Yorkie to promote the supercompetitive behavior of hippo pathway mutant cells.

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    Marcello Ziosi

    2010-09-01

    Full Text Available Genetic analyses in Drosophila epithelia have suggested that the phenomenon of "cell competition" could participate in organ homeostasis. It has been speculated that competition between different cell populations within a growing organ might play a role as either tumor promoter or tumor suppressor, depending on the cellular context. The evolutionarily conserved Hippo (Hpo signaling pathway regulates organ size and prevents hyperplastic disease from flies to humans by restricting the activity of the transcriptional cofactor Yorkie (yki. Recent data indicate also that mutations in several Hpo pathway members provide cells with a competitive advantage by unknown mechanisms. Here we provide insight into the mechanism by which the Hpo pathway is linked to cell competition, by identifying dMyc as a target gene of the Hpo pathway, transcriptionally upregulated by the activity of Yki with different binding partners. We show that the cell-autonomous upregulation of dMyc is required for the supercompetitive behavior of Yki-expressing cells and Hpo pathway mutant cells, whereas the relative levels of dMyc between Hpo pathway mutant cells and wild-type neighboring cells are critical for determining whether cell competition promotes a tumor-suppressing or tumor-inducing behavior. All together, these data provide a paradigmatic example of cooperation between tumor suppressor genes and oncogenes in tumorigenesis and suggest a dual role for cell competition during tumor progression depending on the output of the genetic interactions occurring between confronted cells.

  19. Integrin α6Bβ4 inhibits colon cancer cell proliferation and c-Myc activity

    International Nuclear Information System (INIS)

    Dydensborg, Anders Bondo; Teller, Inga C; Groulx, Jean-François; Basora, Nuria; Paré, Fréderic; Herring, Elizabeth; Gauthier, Rémy; Jean, Dominique; Beaulieu, Jean-François

    2009-01-01

    Integrins are known to be important contributors to cancer progression. We have previously shown that the integrin β4 subunit is up-regulated in primary colon cancer. Its partner, the integrin α6 subunit, exists as two different mRNA splice variants, α6A and α6B, that differ in their cytoplasmic domains but evidence for distinct biological functions of these α6 splice variants is still lacking. In this work, we first analyzed the expression of integrin α6A and α6B at the protein and transcript levels in normal human colonic cells as well as colorectal adenocarcinoma cells from both primary tumors and established cell lines. Then, using forced expression experiments, we investigated the effect of α6A and α6B on the regulation of cell proliferation in a colon cancer cell line. Using variant-specific antibodies, we observed that α6A and α6B are differentially expressed both within the normal adult colonic epithelium and between normal and diseased colonic tissues. Proliferative cells located in the lower half of the glands were found to predominantly express α6A, while the differentiated and quiescent colonocytes in the upper half of the glands and surface epithelium expressed α6B. A relative decrease of α6B expression was also identified in primary colon tumors and adenocarcinoma cell lines suggesting that the α6A/α6B ratios may be linked to the proliferative status of colonic cells. Additional studies in colon cancer cells showed that experimentally restoring the α6A/α6B balance in favor of α6B caused a decrease in cellular S-phase entry and repressed the activity of c-Myc. The findings that the α6Bβ4 integrin is expressed in quiescent normal colonic cells and is significantly down-regulated in colon cancer cells relative to its α6Aβ4 counterpart are consistent with the anti-proliferative influence and inhibitory effect on c-Myc activity identified for this α6Bβ4 integrin. Taken together, these findings point out the importance of integrin

  20. Aspirin regulation of c-myc and cyclinD1 proteins to overcome tamoxifen resistance in estrogen receptor-positive breast cancer cells.

    Science.gov (United States)

    Cheng, Ran; Liu, Ya-Jing; Cui, Jun-Wei; Yang, Man; Liu, Xiao-Ling; Li, Peng; Wang, Zhan; Zhu, Li-Zhang; Lu, Si-Yi; Zou, Li; Wu, Xiao-Qin; Li, Yu-Xia; Zhou, You; Fang, Zheng-Yu; Wei, Wei

    2017-05-02

    Tamoxifen is still the most commonly used endocrine therapy drug for estrogen receptor (ER)-positive breast cancer patients and has an excellent outcome, but tamoxifen resistance remains a great impediment to successful treatment. Recent studies have prompted an anti-tumor effect of aspirin. Here, we demonstrated that aspirin not only inhibits the growth of ER-positive breast cancer cell line MCF-7, especially when combined with tamoxifen, but also has a potential function to overcome tamoxifen resistance in MCF-7/TAM. Aspirin combined with tamoxifen can down regulate cyclinD1 and block cell cycle in G0/G1 phase. Besides, tamoxifen alone represses c-myc, progesterone receptor (PR) and cyclinD1 in MCF-7 cell line but not in MCF-7/TAM, while aspirin combined with tamoxifen can inhibit the expression of these proteins in the resistant cell line. When knocking down c-myc in MCF-7/TAM, cells become more sensitive to tamoxifen, cell cycle is blocked as well, indicating that aspirin can regulate c-myc and cyclinD1 proteins to overcome tamoxifen resistance. Our study discovered a novel role of aspirin based on its anti-tumor effect, and put forward some kinds of possible mechanisms of tamoxifen resistance in ER-positive breast cancer cells, providing a new strategy for the treatment of ER-positive breast carcinoma.

  1. FoxO3A promotes metabolic adaptation to hypoxia by antagonizing Myc function

    DEFF Research Database (Denmark)

    Jensen, Kim Steen; Binderup, Tina; Jensen, Klaus Thorleif

    2011-01-01

    Exposure of metazoan organisms to hypoxia engages a metabolic switch orchestrated by the hypoxia-inducible factor 1 (HIF-1). HIF-1 mediates induction of glycolysis and active repression of mitochondrial respiration that reduces oxygen consumption and inhibits the production of potentially harmful...... tumour tissue in vivo and that FoxO3A short-hairpin RNA (shRNA)-expressing xenograft tumours are decreased in size and metabolically changed. Our findings define a novel mechanism by which FoxO3A promotes metabolic adaptation and stress resistance in hypoxia....... reactive oxygen species (ROS). Here, we show that FoxO3A is activated in hypoxia downstream of HIF-1 and mediates the hypoxic repression of a set of nuclear-encoded mitochondrial genes. FoxO3A is required for hypoxic suppression of mitochondrial mass, oxygen consumption, and ROS production and promotes...... cell survival in hypoxia. FoxO3A is recruited to the promoters of nuclear-encoded mitochondrial genes where it directly antagonizes c-Myc function via a mechanism that does not require binding to the consensus FoxO recognition element. Furthermore, we show that FoxO3A is activated in human hypoxic...

  2. Differential Gene Expression of Fibroblasts: Keloid versus Normal

    Directory of Open Access Journals (Sweden)

    Michael F. Angel

    2002-11-01

    Full Text Available Abstract: This study investigated gene regulation and unique gene products in both keloid (KDF and normal (NDF dermal fibroblasts in established cell lines. For gene regulation, NDF versus KDF were compared using Clontech's Atlas™ Human cDNA Expression Array while unique gene products were studied using RNA Fingerprinting Kit. RNA from each sample was converted to cDNA using oligo-dT primers. Down-regulated genes using Atlas Array in KDF were 1 60 S ribosomal protein, 2 Thioredoxin dependent peroxidase, 3 Nuclease sensitive element DNA binding protein, 4 c-myc purine-binding transcription factor, 5 c-AMP dependent protein kinase, and, 6 Heat Shock Protein 90 kDa. Genes that are up regulated in KDF were 1 Tubulin and 2 Heat Shock Protein 27 kDa. With the differential display, we found 17 bands unique to both KDF and NDF. The specific gene and the manner in which they were differentially regulated have direct implications to understanding keloid fibroblast proliferation.

  3. Disturbance of Bcl-2, Bax, Caspase-3, Ki-67 and C-myc expression in acute and subchronic exposure to benzo(a)pyrene in cervix.

    Science.gov (United States)

    Gao, Meili; Li, Yongfei; Ji, Xiaoying; Xue, Xiaochang; Chen, Lan; Feng, Guodong; Zhang, Huqin; Wang, Huichun; Shah, Walayat; Hou, Zhanwu; Kong, Yu

    2016-03-01

    Epidemiological studies have demonstrated that cigarette smoking is an important cofactor or an independent risk factor for the development of cervical cancer. Benzo(a)pyrene (BaP) is one of the most potent tobacco smoke carcinogens in tobacco smoke. BaP induced DNA damage and over expression in p53 cervical tissue of mice as demonstrated in our previous study. Here we present the findings of exposure to BaP on the expression of Bcl-2, C-myc, Ki-67, Caspase-3 and Bax genes in mouse cervix. Acute intraperitoneal administration of BaP (12.5, 25, 50, 100mg/kg body weight) to ICR female mice induced a significant increase in Bcl-2, C-myc, Ki-67 mRNA and protein level till 72h except in Bcl-2 at 24h with 12.5, 25, 50mg/kg as well as at 48h with 12.5mg/kg body weight post treatment. A significant increase was also seen in Caspase-3 and Bax mRNA and protein level with peak level at 24h and gradual decrease till 72h, however, the expression of caspase-3 increased while that of Bax decreased with increasing dose of Bap after 24h. In sub chronic intraperitoneal and oral gavage administration of BaP (2.5, 5, 10mg/kg body weight), similar significant increase was observed for all the examined genes as compared to the control and vehicle groups, however the expression of Bax decreased in a dose dependent manner. The findings of this study will help in further understanding the molecular mechanism of BaP induced carcinogenesis of cervical cancer. Copyright © 2015 Elsevier GmbH. All rights reserved.

  4. Cell culture density affects the stemness gene expression of adipose tissue-derived mesenchymal stem cells.

    Science.gov (United States)

    Kim, Dae Seong; Lee, Myoung Woo; Lee, Tae-Hee; Sung, Ki Woong; Koo, Hong Hoe; Yoo, Keon Hee

    2017-03-01

    The results of clinical trials using mesenchymal stem cells (MSCs) are controversial due to the heterogeneity of human MSCs and differences in culture conditions. In this regard, it is important to identify gene expression patterns according to culture conditions, and to determine how the cells are expanded and when they should be clinically used. In the current study, stemness gene expression was investigated in adipose tissue-derived MSCs (AT-MSCs) harvested following culture at different densities. AT-MSCs were plated at a density of 200 or 5,000 cells/cm 2 . After 7 days of culture, stemness gene expression was examined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis. The proliferation rate of AT-MSCs harvested at a low density (~50% confluent) was higher than that of AT-MSCs harvested at a high density (~90% confluent). Although there were differences in the expression levels of stemness gene, such as octamer-binding transcription factor 4, nanog homeobox ( Nanog ), SRY-box 2, Kruppel like factor 4, v-myc avian myelocytomatosis viral oncogene homolog ( c-Myc ), and lin-28 homolog A, in the AT-MSCs obtained from different donors, RT-qPCR analysis demonstrated differential gene expression patterns according to the cell culture density. Expression levels of stemness genes, particularly Nanog and c-Myc , were upregulated in AT-MSCs harvested at a low density (~50% confluent) in comparison to AT-MSCs from the same donor harvested at a high density (~90% confluent). These results imply that culture conditions, such as the cell density at harvesting, modulate the stemness gene expression and proliferation of MSCs.

  5. Cis-acting elements in the promoter region of the human aldolase C gene.

    Science.gov (United States)

    Buono, P; de Conciliis, L; Olivetta, E; Izzo, P; Salvatore, F

    1993-08-16

    We investigated the cis-acting sequences involved in the expression of the human aldolase C gene by transient transfections into human neuroblastoma cells (SKNBE). We demonstrate that 420 bp of the 5'-flanking DNA direct at high efficiency the transcription of the CAT reporter gene. A deletion between -420 bp and -164 bp causes a 60% decrease of CAT activity. Gel shift and DNase I footprinting analyses revealed four protected elements: A, B, C and D. Competition analyses indicate that Sp1 or factors sharing a similar sequence specificity bind to elements A and B, but not to elements C and D. Sequence analysis shows a half palindromic ERE motif (GGTCA), in elements B and D. Region D binds a transactivating factor which appears also essential to stabilize the initiation complex.

  6. TSA suppresses miR-106b-93-25 cluster expression through downregulation of MYC and inhibits proliferation and induces apoptosis in human EMC.

    Science.gov (United States)

    Zhao, Zhi-Ning; Bai, Jiu-Xu; Zhou, Qiang; Yan, Bo; Qin, Wei-Wei; Jia, Lin-Tao; Meng, Yan-Ling; Jin, Bo-Quan; Yao, Li-Bo; Wang, Tao; Yang, An-Gang

    2012-01-01

    Histone deacetylase (HDAC) inhibitors are emerging as a novel class of anti-tumor agents and have manifested the ability to decrease proliferation and increase apoptosis in different cancer cells. A significant number of genes have been identified as potential effectors responsible for the anti-tumor function of HDAC inhibitor. However, the molecular mechanisms of these HDAC inhibitors in this process remain largely undefined. In the current study, we searched for microRNAs (miRs) that were affected by HDAC inhibitor trichostatin (TSA) and investigated their effects in endometrial cancer (EMC) cells. Our data showed that TSA significantly inhibited the growth of EMC cells and induced their apoptosis. Among the miRNAs that altered in the presence of TSA, the miR-106b-93-25 cluster, together with its host gene MCM7, were obviously down-regulated in EMC cells. p21 and BIM, which were identified as target genes of miR-106b-93-25 cluster, increased in TSA treated tumor cells and were responsible for cell cycle arrest and apoptosis. We further identified MYC as a regulator of miR-106b-93-25 cluster and demonstrated its down-regulation in the presence of TSA resulted in the reduction of miR-106b-93-25 cluster and up-regulation of p21 and BIM. More important, we found miR-106b-93-25 cluster was up-regulated in clinical EMC samples in association with the overexpression of MCM7 and MYC and the down-regulation of p21 and BIM. Thus our studies strongly indicated TSA inhibited EMC cell growth and induced cell apoptosis and cell cycle arrest at least partially through the down-regulation of the miR-106b-93-25 cluster and up-regulation of it's target genes p21 and BIM via MYC.

  7. Modulation of RIZ gene expression is associated to estradiol control of MCF-7 breast cancer cell proliferation

    International Nuclear Information System (INIS)

    Gazzerro, Patrizia; Abbondanza, Ciro; D'Arcangelo, Andrea; Rossi, Mariangela; Medici, Nicola; Moncharmont, Bruno; Puca, Giovanni Alfredo

    2006-01-01

    The retinoblastoma protein-interacting zinc-finger (RIZ) gene, a member of the nuclear protein methyltransferase superfamily, is characterized by the presence of the N-terminal PR domain. The RIZ gene encodes for two proteins, RIZ1 and RIZ2. While RIZ1 contains the PR (PRDI-BF1 and RIZ homologous) domain, RIZ2 lacks it. RIZ gene expression is altered in a variety of human cancers and RIZ1 is now considered to be a candidate tumor suppressor. Estradiol treatment of MCF-7 cells produced a selective decrease of RIZ1 transcript and an increase of total RIZ mRNA. Experiments of chromatin immunoprecipitation indicated that RIZ2 protein expression was controlled by estrogen receptor and RIZ1 had a direct repressor function on c-myc gene expression. To investigate the role of RIZ gene products as regulators of the proliferation/differentiation transition, we analyzed the effects of forced suppression of RIZ1 induced in MCF-7 cells by siRNA of the PR domain-containing form. Silencing of RIZ1 expression stimulated cell proliferation, similar to the effect of estradiol on these cells, associated with a transient increase of c-myc expression

  8. The prognosis of MYC translocation positive diffuse large B-cell lymphoma depends on the second hit.

    Science.gov (United States)

    Clipson, Alexandra; Barrans, Sharon; Zeng, Naiyan; Crouch, Simon; Grigoropoulos, Nicholas F; Liu, Hongxiang; Kocialkowski, Sylvia; Wang, Ming; Huang, Yuanxue; Worrillow, Lisa; Goodlad, John; Buxton, Jenny; Neat, Michael; Fields, Paul; Wilkins, Bridget; Grant, John W; Wright, Penny; Ei-Daly, Hesham; Follows, George A; Roman, Eve; Watkins, A James; Johnson, Peter W M; Jack, Andrew; Du, Ming-Qing

    2015-07-01

    A proportion of MYC translocation positive diffuse large B-cell lymphomas (DLBCL) harbour a BCL2 and/or BCL6 translocation, known as double-hit DLBCL, and are clinically aggressive. It is unknown whether there are other genetic abnormalities that cooperate with MYC translocation and form double-hit DLBCL, and whether there is a difference in clinical outcome between the double-hit DLBCL and those with an isolated MYC translocation. We investigated TP53 gene mutations along with BCL2 and BCL6 translocations in a total of 234 cases of DLBCL, including 81 with MYC translocation. TP53 mutations were investigated by PCR and sequencing, while BCL2 and BCL6 translocation was studied by interphase fluorescence in situ hybridization. The majority of MYC translocation positive DLBCLs (60/81 = 74%) had at least one additional genetic hit. In MYC translocation positive DLBCL treated by R-CHOP ( n  = 67), TP53 mutation and BCL2, but not BCL6 translocation had an adverse effect on patient overall survival. In comparison with DLBCL with an isolated MYC translocation, cases with MYC/TP53 double-hits had the worst overall survival, followed by those with MYC/BCL2 double-hits. In MYC translocation negative DLBCL treated by R-CHOP ( n  = 101), TP53 mutation, BCL2 and BCL6 translocation had no impact on patient survival. The prognosis of MYC translocation positive DLBCL critically depends on the second hit, with TP53 mutations and BCL2 translocation contributing to an adverse prognosis. It is pivotal to investigate both TP53 mutations and BCL2 translocations in MYC translocation positive DLBCL, and to distinguish double-hit DLBCLs from those with an isolated MYC translocation.

  9. Adenovirus E4ORF1-induced MYC activation promotes host cell anabolic glucose metabolism and virus replication.

    Science.gov (United States)

    Thai, Minh; Graham, Nicholas A; Braas, Daniel; Nehil, Michael; Komisopoulou, Evangelia; Kurdistani, Siavash K; McCormick, Frank; Graeber, Thomas G; Christofk, Heather R

    2014-04-01

    Virus infections trigger metabolic changes in host cells that support the bioenergetic and biosynthetic demands of viral replication. Although recent studies have characterized virus-induced changes in host cell metabolism (Munger et al., 2008; Terry et al., 2012), the molecular mechanisms by which viruses reprogram cellular metabolism have remained elusive. Here, we show that the gene product of adenovirus E4ORF1 is necessary for adenovirus-induced upregulation of host cell glucose metabolism and sufficient to promote enhanced glycolysis in cultured epithelial cells by activation of MYC. E4ORF1 localizes to the nucleus, binds to MYC, and enhances MYC binding to glycolytic target genes, resulting in elevated expression of specific glycolytic enzymes. E4ORF1 activation of MYC promotes increased nucleotide biosynthesis from glucose intermediates and enables optimal adenovirus replication in primary lung epithelial cells. Our findings show how a viral protein exploits host cell machinery to reprogram cellular metabolism and promote optimal progeny virion generation. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Shikonin regulates C-MYC and GLUT1 expression through the MST1-YAP1-TEAD1 axis

    Czech Academy of Sciences Publication Activity Database

    Vališ, Karel; Talacko, Pavel; Grobárová, Valeria; Černý, J.; Novák, Petr

    2016-01-01

    Roč. 349, č. 2 (2016), s. 273-281 ISSN 0014-4827 R&D Projects: GA ČR(CZ) GP14-21095P; GA ČR GA13-16565S; GA MŠk(CZ) LQ1604; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61388971 Keywords : Hippo * Glycolysis * C-MYC Subject RIV: EE - Microbiology, Virology Impact factor: 3.546, year: 2016

  11. Colocalization of somatic and meiotic double strand breaks near the Myc oncogene on mouse chromosome 15.

    Science.gov (United States)

    Ng, Siemon H; Maas, Sarah A; Petkov, Petko M; Mills, Kevin D; Paigen, Kenneth

    2009-10-01

    Both somatic and meiotic recombinations involve the repair of DNA double strand breaks (DSBs) that occur at preferred locations in the genome. Improper repair of DSBs during either mitosis or meiosis can lead to mutations, chromosomal aberration such as translocations, cancer, and/or cell death. Currently, no model exists that explains the locations of either spontaneous somatic DSBs or programmed meiotic DSBs or relates them to each other. One common class of tumorigenic translocations arising from DSBs is chromosomal rearrangements near the Myc oncogene. Myc translocations have been associated with Burkitt lymphoma in humans, plasmacytoma in mice, and immunocytoma in rats. Comparing the locations of somatic and meiotic DSBs near the mouse Myc oncogene, we demonstrated that the placement of these DSBs is not random and that both events clustered in the same short discrete region of the genome. Our work shows that both somatic and meiotic DSBs tend to occur in proximity to each other within the Myc region, suggesting that they share common originating features. It is likely that some regions of the genome are more susceptible to both somatic and meiotic DSBs, and the locations of meiotic hotspots may be an indicator of genomic regions more susceptible to DNA damage. (c) 2009 Wiley-Liss, Inc.

  12. Mechanisms for c-myc Induced Mouse Mammary Gland Carcinogenesis and for the Synergistic Role of TGF(alpha) in the Process

    Science.gov (United States)

    2001-07-01

    1242 11-28. anti-tumor effects with microencapsulated c-myc antisense Panico L, D’Antonio A, Salvatore G, Mezza E, Tortora G, De oligonucleotide... enzymatic conversion of androgens to estrogens, since an estrogen receptor antagonist cannot block the lobular- alveolar induction by T, DHT

  13. Two populations of double minute chromosomes harbor distinct amplicons, the MYC locus at 8q24.2 and a 0.43-Mb region at 14q24.1, in the SW613-S human carcinoma cell line.

    Science.gov (United States)

    Guillaud-Bataille, M; Brison, O; Danglot, G; Lavialle, C; Raynal, B; Lazar, V; Dessen, P; Bernheim, A

    2009-01-01

    High-level amplifications observed in tumor cells are usually indicative of genes involved in oncogenesis. We report here a high resolution characterization of a new amplified region in the SW613-S carcinoma cell line. This cell line contains tumorigenic cells displaying high-level MYC amplification in the form of double minutes (DM(+) cells) and non tumorigenic cells exhibiting low-level MYC amplification in the form of homogeneously staining regions (DM(-) cells). Both cell types were studied at genomic and functional levels. The DM(+) cells display a second amplification, corresponding to the 14q24.1 region, in a distinct population of DMs. The 0.43-Mb amplified and overexpressed region contains the PLEK2, PIGH, ARG2, VTI1B, RDH11, and ZFYVE26 genes. Both amplicons were stably maintained upon in vitro and in vivo propagation. However, the 14q24.1 amplicon was not found in cells with high-level MYC amplification in the form of HSRs, either obtained after spontaneous integration of endogenous DM MYC copies or after transfection of DM(-) cells with a MYC gene expression vector. These HSR-bearing cells are highly tumorigenic. The 14q24.1 amplification may not play a role in malignancy per se but might contribute to maintaining the amplification in the form of DMs. Copyright 2009 S. Karger AG, Basel.

  14. The Indolic Diet-Derivative, 3,3′-Diindolylmethane, Induced Apoptosis in Human Colon Cancer Cells through Upregulation of NDRG1

    Directory of Open Access Journals (Sweden)

    A. Lerner

    2012-01-01

    Full Text Available N-myc downstream regulated gene-1 participates in carcinogenesis, angiogenesis, metastases, and anticancer drug resistance. In the present study, we analyzed the expression pattern of N-myc downstream regulated gene-1 following treatment of human colonic cancer cell lines; HCT-116 (well differentiated with wild-type p53 gene and Colo-320 (poorly differentiated with mutant p53 gene, with 3,3′-diindolylmethane, a well-established proapoptotic agent product derived from indole-3-carbinol. Treatment of Colo-320 and HCT-116 with 3,3′-diindolylmethane disclosed inhibition of cell viability in a dose-dependent manner, mediated through apoptosis induction. The increased expression of N-myc downstream regulated gene-1 was detected only in poorly differentiated colon cancer cells, Colo-320 cell line. Our results suggest that N-myc downstream regulated gene-1 expression is enhanced by 3,3′-diindolylmethane in poorly differentiated cells and followed by induction of apoptosis. 3,3′-diindolylmethane induced apoptosis may represent a new regulator of N-myc downstream regulated gene-1 in poorly differentiated colonic cancer cells.

  15. Differential Requirements for c-Myc in Chronic Hematopoietic Hyperplasia and Acute Hematopoietic Malignancies in Pten-null Mice

    Science.gov (United States)

    Zhang, Jun; Xiao, Yechen; Guo, Yinshi; Breslin, Peter; Zhang, Shubin; Wei, Wei; Zhang, Zhou; Zhang, Jiwang

    2011-01-01

    Myeloproliferative disorders (MPDs), lymphoproliferative disorders (LPDs), acute T-lymphocytic or myeloid leukemia and T-lymphocytic lymphoma were developed in inducible Pten-knockout (Pten−/−) mice. The appearance of these multiple diseases in one animal model provides an opportunity to study the pathogenesis of multiple diseases simultaneously. To study whether Myc function is required for the development of these hematopoietic disorders in Pten−/− mice, we generated inducible Pten/Myc double-knockout mice (Pten−/−/Myc−/−). By comparing the hematopoietic phenotypes of these double-knockout mice with those of Pten−/− mice, we found that both sets of animals developed MPDs and LPDs. However, none of the compound-mutant mice developed acute leukemia or lymphoma. Interestingly, in contrast to the MPDs which developed in Pten−/− mice which are dominated by granulocytes, megakaryocytes predominate in the MPDs of Pten−/−/Myc−/− mice. Our study suggests that the deregulation of PI3K/Akt signaling in Pten−/− hematopoietic cells protects these cells from apoptotic cell death, resulting in chronic proliferative disorders. But due to the differential requirement for Myc in granulocyte as compared to megakaryocyte proliferation, Myc deletion converts Pten−/− MPDs from granulocyte-dominated to megakaryocyte-dominated conditions. Myc is absolutely required for the development of acute hematopoietic malignancies. PMID:21926961

  16. Regulation of c-Myc mRNA by L11 in Response to UV and Gamma Irradiation

    Science.gov (United States)

    2014-12-01

    the nucleolus fol- lowed by their transport into the cytoplasm (50). This process requires coordinated transcription catalyzed by all three RNA...these RPs, including L11, are released from the nucleolus or from intact ribosomes to suppress MDM2 (68). However, whether L11 suppresses c-Myc in...centrifugation. For isolation of the nucleolus fraction, the nuclear pellets were resuspended in buffer S1 containing 0.25 M sucrose and 10 mM MgCl2, layered over

  17. The cucurbitacins D, E, and I from Ecballium elaterium (L. upregulate the LC3 gene and induce cell-cycle arrest in human gastric cancer cell line AGS

    Directory of Open Access Journals (Sweden)

    Naser Jafargholizadeh

    2018-03-01

    Full Text Available Objective(s: Cucurbitacins exhibit a range of anti-cancer functions. We investigated the effects of cucurbitacins D, E, and I purified from Ecballium elaterium (L. A. Rich fruits on some apoptotic and autophagy genes in human gastric cancer cell line AGS. Materials and Methods: Using quantitative reverse transcription PCR (qRT-PCR, the expression of LC3, VEGF, BAX, caspase-3, and c-MYC genes were quantified in AGS cells 24 hr after treatment with cucurbitacins D, E, and I at concentrations 0.3, 0.1 and 0.5 μg/ml, respectively. Cell cycle and death were analyzed by flowcytometry. Results: Purified cucurbitacins induced sub-G1 cell-cycle arrest and cell death in AGS cells and upregulated LC3mRNA effectively, but showed a very low effect on BAX, caspase-3, and c-MYC mRNA levels. Also after treatment with cucurbitacin I at concentration 0.5 μg/ml, VEGF mRNA levels were increased about 4.4 times. Pairwise comparison of the effect of cucurbitacins D, E, and I on LC3 mRNA expression showed that the cucurbitacin I effect is 1.3 and 1.1 times that of cucurbitacins E and D, respectively; cucurbitacin D effect is 1.2 times that of cucurbitacin E (P-value

  18. The endogenous retroviral insertion in the human complement C4 gene modulates the expression of homologous genes by antisense inhibition.

    Science.gov (United States)

    Schneider, P M; Witzel-Schlömp, K; Rittner, C; Zhang, L

    2001-02-01

    Intron 9 contains the complete endogenous retrovirus HERV-K(C4) as a 6.4-kb insertion in 60% of human C4 genes. The retroviral insertion is in reverse orientation to the C4 coding sequence. Therefore, expression of C4 could lead to the transcription of an antisense RNA, which might protect against exogenous retroviral infections. To test this hypothesis, open reading frames from the HERV sequence were subcloned in sense orientiation into a vector allowing expression of a beta-galactosidase fusion protein. Mouse L cells which had been stably transfected with either the human C4A or C4B gene both carrying the HERV insertion (LC4 cells), and L(Tk-) cells without the C4 gene were transiently transfected either with a retroviral construct or with the wild-type vector. Expression was monitored using an enzymatic assay. We demonstrated that (1) HERV-K(C4) antisense mRNA transcripts are present in cells constitutively expressing C4, (2) expression of retroviral-like constructs is significantly downregulated in cells expressing C4, and (3) this downregulation is further modulated in a dose-dependent fashion following interferon-gamma stimulation of C4 expression. These results support the hypothesis of a genomic antisense strategy mediated by the HERV-K(C4) insertion as a possible defense mechanism against exogenous retroviral infections.

  19. Epigenetic regulation of multiple tumor-related genes leads to suppression of breast tumorigenesis by dietary genistein.

    Directory of Open Access Journals (Sweden)

    Yuanyuan Li

    Full Text Available Breast cancer is one of the most lethal diseases in women; however, the precise etiological factors are still not clear. Genistein (GE, a natural isoflavone found in soybean products, is believed to be a potent chemopreventive agent for breast cancer. One of the most important mechanisms for GE inhibition of breast cancer may involve its potential in impacting epigenetic processes allowing reversal of aberrant epigenetic events during breast tumorigenesis. To investigate epigenetic regulation for GE impedance of breast tumorigenesis, we monitored epigenetic alterations of several key tumor-related genes in an established breast cancer transformation system. Our results show that GE significantly inhibited cell growth in a dose-dependent manner in precancerous breast cells and breast cancer cells, whereas it exhibited little effect on normal human mammary epithelial cells. Furthermore, GE treatment increased expression of two crucial tumor suppressor genes, p21(WAF1 (p21 and p16(INK4a (p16, although it decreased expression of two tumor promoting genes, BMI1 and c-MYC. GE treatment led to alterations of histone modifications in the promoters of p21 and p16 as well as the binding ability of the c-MYC-BMI1 complex to the p16 promoter contributing to GE-induced epigenetic activation of these tumor suppressor genes. In addition, an orally-fed GE diet prevented breast tumorigenesis and inhibited breast cancer development in breast cancer mice xenografts. Our results suggest that genistein may repress early breast tumorigenesis by epigenetic regulation of p21 and p16 by impacting histone modifications as well as the BMI1-c-MYC complex recruitment to the regulatory region in the promoters of these genes. These studies will facilitate more effective use of soybean product in breast cancer prevention and also help elucidate the mechanisms during the process of early breast tumorigenesis.

  20. Epigenetic regulation of multiple tumor-related genes leads to suppression of breast tumorigenesis by dietary genistein.

    Science.gov (United States)

    Li, Yuanyuan; Chen, Huaping; Hardy, Tabitha M; Tollefsbol, Trygve O

    2013-01-01

    Breast cancer is one of the most lethal diseases in women; however, the precise etiological factors are still not clear. Genistein (GE), a natural isoflavone found in soybean products, is believed to be a potent chemopreventive agent for breast cancer. One of the most important mechanisms for GE inhibition of breast cancer may involve its potential in impacting epigenetic processes allowing reversal of aberrant epigenetic events during breast tumorigenesis. To investigate epigenetic regulation for GE impedance of breast tumorigenesis, we monitored epigenetic alterations of several key tumor-related genes in an established breast cancer transformation system. Our results show that GE significantly inhibited cell growth in a dose-dependent manner in precancerous breast cells and breast cancer cells, whereas it exhibited little effect on normal human mammary epithelial cells. Furthermore, GE treatment increased expression of two crucial tumor suppressor genes, p21(WAF1) (p21) and p16(INK4a) (p16), although it decreased expression of two tumor promoting genes, BMI1 and c-MYC. GE treatment led to alterations of histone modifications in the promoters of p21 and p16 as well as the binding ability of the c-MYC-BMI1 complex to the p16 promoter contributing to GE-induced epigenetic activation of these tumor suppressor genes. In addition, an orally-fed GE diet prevented breast tumorigenesis and inhibited breast cancer development in breast cancer mice xenografts. Our results suggest that genistein may repress early breast tumorigenesis by epigenetic regulation of p21 and p16 by impacting histone modifications as well as the BMI1-c-MYC complex recruitment to the regulatory region in the promoters of these genes. These studies will facilitate more effective use of soybean product in breast cancer prevention and also help elucidate the mechanisms during the process of early breast tumorigenesis.

  1. A candidate-gene association study for berry colour and anthocyanin content in Vitis vinifera L.

    Directory of Open Access Journals (Sweden)

    Silvana Cardoso

    Full Text Available Anthocyanin content is a trait of major interest in Vitis vinifera L. These compounds affect grape and wine quality, and have beneficial effects on human health. A candidate-gene approach was used to identify genetic variants associated with anthocyanin content in grape berries. A total of 445 polymorphisms were identified in 5 genes encoding transcription factors and 10 genes involved in either the biosynthetic pathway or transport of anthocyanins. A total of 124 SNPs were selected to examine association with a wide range of phenotypes based on RP-HPLC analysis and visual characterization. The phenotypes were total skin anthocyanin (TSA concentration but also specific types of anthocyanins and relative abundance. The visual assessment was based on OIV (Organisation Internationale de la Vigne et du Vin descriptors for berry and skin colour. The genes encoding the transcription factors MYB11, MYBCC and MYC(B were significantly associated with TSA concentration. UFGT and MRP were associated with several different types of anthocyanins. Skin and pulp colour were associated with nine genes (MYB11, MYBCC, MYC(B, UFGT, MRP, DFR, LDOX, CHI and GST. Pulp colour was associated with a similar group of 11 genes (MYB11, MYBCC, MYC(B, MYC(A, UFGT, MRP, GST, DFR, LDOX, CHI and CHS(A. Statistical interactions were observed between SNPs within the transcription factors MYB11, MYBCC and MYC(B. SNPs within LDOX interacted with MYB11 and MYC(B, while SNPs within CHI interacted with MYB11 only. Together, these findings suggest the involvement of these genes in anthocyanin content and on the regulation of anthocyanin biosynthesis. This work forms a benchmark for replication and functional studies.

  2. Mutational landscape of EGFR-, MYC-, and Kras-driven genetically engineered mouse models of lung adenocarcinoma.

    Science.gov (United States)

    McFadden, David G; Politi, Katerina; Bhutkar, Arjun; Chen, Frances K; Song, Xiaoling; Pirun, Mono; Santiago, Philip M; Kim-Kiselak, Caroline; Platt, James T; Lee, Emily; Hodges, Emily; Rosebrock, Adam P; Bronson, Roderick T; Socci, Nicholas D; Hannon, Gregory J; Jacks, Tyler; Varmus, Harold

    2016-10-18

    Genetically engineered mouse models (GEMMs) of cancer are increasingly being used to assess putative driver mutations identified by large-scale sequencing of human cancer genomes. To accurately interpret experiments that introduce additional mutations, an understanding of the somatic genetic profile and evolution of GEMM tumors is necessary. Here, we performed whole-exome sequencing of tumors from three GEMMs of lung adenocarcinoma driven by mutant epidermal growth factor receptor (EGFR), mutant Kirsten rat sarcoma viral oncogene homolog (Kras), or overexpression of MYC proto-oncogene. Tumors from EGFR- and Kras-driven models exhibited, respectively, 0.02 and 0.07 nonsynonymous mutations per megabase, a dramatically lower average mutational frequency than observed in human lung adenocarcinomas. Tumors from models driven by strong cancer drivers (mutant EGFR and Kras) harbored few mutations in known cancer genes, whereas tumors driven by MYC, a weaker initiating oncogene in the murine lung, acquired recurrent clonal oncogenic Kras mutations. In addition, although EGFR- and Kras-driven models both exhibited recurrent whole-chromosome DNA copy number alterations, the specific chromosomes altered by gain or loss were different in each model. These data demonstrate that GEMM tumors exhibit relatively simple somatic genotypes compared with human cancers of a similar type, making these autochthonous model systems useful for additive engineering approaches to assess the potential of novel mutations on tumorigenesis, cancer progression, and drug sensitivity.

  3. Mutational landscape of EGFR-, MYC-, and Kras-driven genetically engineered mouse models of lung adenocarcinoma

    Science.gov (United States)

    McFadden, David G.; Politi, Katerina; Bhutkar, Arjun; Chen, Frances K.; Song, Xiaoling; Pirun, Mono; Santiago, Philip M.; Kim-Kiselak, Caroline; Platt, James T.; Lee, Emily; Hodges, Emily; Rosebrock, Adam P.; Bronson, Roderick T.; Socci, Nicholas D.; Hannon, Gregory J.; Jacks, Tyler; Varmus, Harold

    2016-01-01

    Genetically engineered mouse models (GEMMs) of cancer are increasingly being used to assess putative driver mutations identified by large-scale sequencing of human cancer genomes. To accurately interpret experiments that introduce additional mutations, an understanding of the somatic genetic profile and evolution of GEMM tumors is necessary. Here, we performed whole-exome sequencing of tumors from three GEMMs of lung adenocarcinoma driven by mutant epidermal growth factor receptor (EGFR), mutant Kirsten rat sarcoma viral oncogene homolog (Kras), or overexpression of MYC proto-oncogene. Tumors from EGFR- and Kras-driven models exhibited, respectively, 0.02 and 0.07 nonsynonymous mutations per megabase, a dramatically lower average mutational frequency than observed in human lung adenocarcinomas. Tumors from models driven by strong cancer drivers (mutant EGFR and Kras) harbored few mutations in known cancer genes, whereas tumors driven by MYC, a weaker initiating oncogene in the murine lung, acquired recurrent clonal oncogenic Kras mutations. In addition, although EGFR- and Kras-driven models both exhibited recurrent whole-chromosome DNA copy number alterations, the specific chromosomes altered by gain or loss were different in each model. These data demonstrate that GEMM tumors exhibit relatively simple somatic genotypes compared with human cancers of a similar type, making these autochthonous model systems useful for additive engineering approaches to assess the potential of novel mutations on tumorigenesis, cancer progression, and drug sensitivity. PMID:27702896

  4. Melatonin promotes circadian rhythm-induced proliferation through Clock/histone deacetylase 3/c-Myc interaction in mouse adipose tissue.

    Science.gov (United States)

    Liu, Zhenjiang; Gan, Lu; Luo, Dan; Sun, Chao

    2017-05-01

    Melatonin is synthesized in the pineal gland and controls circadian rhythm of peripheral adipose tissue, resulting in changes in body weight. Although core regulatory components of clock rhythmicity have been defined, insight into the mechanisms of circadian rhythm-mediated proliferation in adipose tissue is still limited. Here, we showed that melatonin (20 mg/kg/d) promoted circadian and proliferation processes in white adipose tissue. The circadian amplitudes of brain and muscle aryl hydrocarbon receptor nuclear translocator-like 1 (Bmal1, Pcircadian locomotor output cycles kaput (Clock, Pcircadian disruption and promoted adipocyte proliferation in chronic jet-lagged mice and obese mice. Thus, our study found that melatonin promoted adipocyte proliferation by forming a Clock/HDAC3/c-Myc complex and subsequently driving the circadian amplitudes of proliferation genes. Our data reveal a novel mechanism that links circadian rhythm to cell proliferation in adipose tissue. These findings also identify a new potential means for melatonin to prevent and treat sleep deprivation-caused obesity. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  5. The use of computerized video time lapse to study cell death in rat embryo cells transfected with c-ha-ras or c-myc

    International Nuclear Information System (INIS)

    Forrester, H.B.; Vidair, C.A.; Dewey, W.C.; Ling, C.C.

    1998-01-01

    Full text: Individual rat embryo fibroblasts that had been transfected with the c-myc (REC:myc) or c-Ha ras (REC:ras) oncogene were followed after irradiation using a computer video time lapse (CVTL) system in order to quantify the lethal events that resulted in loss of clonogenic survival after irradiation. By followed the cells for 2 to 3 generations before irradiation we were able to determine where they were in the cell cycle at the time of irradiation for cell cycle analysis. After irradiation, the individual cells and their progeny were followed in multiple fields for 5-6 days Then, pedigrees for individual irradiated cells were determined by noting the times of divisions fusions, and cell death. After X-irradiation, the clonogenic survival values for these two cell lines are similar. However, by using computerized video time lapse (CVTL) to follow individual cells we found that the loss of clonogenic survival was due to two different processes, cell death and a senescent-like process. The loss of clonogenic survival of x-irradiated (9.5 and 4 Gy) REC:myc cells was attributed almost entirely to the cells dying by apoptosis (∼99 and 90%). In contrast, approximately 60% of the x-irradiated (9.5 Gy) non-clonogenic REC:ras cells died by apoptosis (with a very small amount of necrosis), and the other 40% underwent a senescent-type process in which some of the cells and their progeny stopped dividing but remained as viable cells throughout 140 hours of observation. Both processes usually occurred after the cells had divided and continued to occur in the cells' progeny for up to five divisions after irradiation. The mode of cell death in the progeny of a non-clonogenic cell can be determined only by using CVTL and can not be determined by conventional clonogenic survival experiments. Also, only by following the individual cells and their progeny can the true amount of apoptosis be determined. The cumulative percentage of apoptosis scored in whole populations

  6. Drosophila insulin and target of rapamycin (TOR pathways regulate GSK3 beta activity to control Myc stability and determine Myc expression in vivo

    Directory of Open Access Journals (Sweden)

    Parisi Federica

    2011-09-01

    Full Text Available Abstract Background Genetic studies in Drosophila melanogaster reveal an important role for Myc in controlling growth. Similar studies have also shown how components of the insulin and target of rapamycin (TOR pathways are key regulators of growth. Despite a few suggestions that Myc transcriptional activity lies downstream of these pathways, a molecular mechanism linking these signaling pathways to Myc has not been clearly described. Using biochemical and genetic approaches we tried to identify novel mechanisms that control Myc activity upon activation of insulin and TOR signaling pathways. Results Our biochemical studies show that insulin induces Myc protein accumulation in Drosophila S2 cells, which correlates with a decrease in the activity of glycogen synthase kinase 3-beta (GSK3β a kinase that is responsible for Myc protein degradation. Induction of Myc by insulin is inhibited by the presence of the TOR inhibitor rapamycin, suggesting that insulin-induced Myc protein accumulation depends on the activation of TOR complex 1. Treatment with amino acids that directly activate the TOR pathway results in Myc protein accumulation, which also depends on the ability of S6K kinase to inhibit GSK3β activity. Myc upregulation by insulin and TOR pathways is a mechanism conserved in cells from the wing imaginal disc, where expression of Dp110 and Rheb also induces Myc protein accumulation, while inhibition of insulin and TOR pathways result in the opposite effect. Our functional analysis, aimed at quantifying the relative contribution of Myc to ommatidial growth downstream of insulin and TOR pathways, revealed that Myc activity is necessary to sustain the proliferation of cells from the ommatidia upon Dp110 expression, while its contribution downstream of TOR is significant to control the size of the ommatidia. Conclusions Our study presents novel evidence that Myc activity acts downstream of insulin and TOR pathways to control growth in Drosophila. At

  7. Drosophila insulin and target of rapamycin (TOR) pathways regulate GSK3 beta activity to control Myc stability and determine Myc expression in vivo.

    Science.gov (United States)

    Parisi, Federica; Riccardo, Sara; Daniel, Margaret; Saqcena, Mahesh; Kundu, Nandini; Pession, Annalisa; Grifoni, Daniela; Stocker, Hugo; Tabak, Esteban; Bellosta, Paola

    2011-09-27

    Genetic studies in Drosophila melanogaster reveal an important role for Myc in controlling growth. Similar studies have also shown how components of the insulin and target of rapamycin (TOR) pathways are key regulators of growth. Despite a few suggestions that Myc transcriptional activity lies downstream of these pathways, a molecular mechanism linking these signaling pathways to Myc has not been clearly described. Using biochemical and genetic approaches we tried to identify novel mechanisms that control Myc activity upon activation of insulin and TOR signaling pathways. Our biochemical studies show that insulin induces Myc protein accumulation in Drosophila S2 cells, which correlates with a decrease in the activity of glycogen synthase kinase 3-beta (GSK3β ) a kinase that is responsible for Myc protein degradation. Induction of Myc by insulin is inhibited by the presence of the TOR inhibitor rapamycin, suggesting that insulin-induced Myc protein accumulation depends on the activation of TOR complex 1. Treatment with amino acids that directly activate the TOR pathway results in Myc protein accumulation, which also depends on the ability of S6K kinase to inhibit GSK3β activity. Myc upregulation by insulin and TOR pathways is a mechanism conserved in cells from the wing imaginal disc, where expression of Dp110 and Rheb also induces Myc protein accumulation, while inhibition of insulin and TOR pathways result in the opposite effect. Our functional analysis, aimed at quantifying the relative contribution of Myc to ommatidial growth downstream of insulin and TOR pathways, revealed that Myc activity is necessary to sustain the proliferation of cells from the ommatidia upon Dp110 expression, while its contribution downstream of TOR is significant to control the size of the ommatidia. Our study presents novel evidence that Myc activity acts downstream of insulin and TOR pathways to control growth in Drosophila. At the biochemical level we found that both these pathways

  8. Copper/MYC/CTR1 interplay: a dangerous relationship in hepatocellular carcinoma.

    Science.gov (United States)

    Porcu, Cristiana; Antonucci, Laura; Barbaro, Barbara; Illi, Barbara; Nasi, Sergio; Martini, Maurizio; Licata, Anna; Miele, Luca; Grieco, Antonio; Balsano, Clara

    2018-02-06

    Free serum copper correlates with tumor incidence and progression of human cancers, including hepatocellular carcinoma (HCC). Copper extracellular uptake is provided by the transporter CTR1, whose expression is regulated to avoid excessive intracellular copper entry. Inadequate copper serum concentration is involved in the pathogenesis of Non Alcoholic Fatty Liver Disease (NAFLD), which is becoming a major cause of liver damage progression and HCC incidence. Finally, MYC is over-expressed in most of HCCs and is a critical regulator of cellular growth, tumor invasion and metastasis. The purpose of our study was to understand if higher serum copper concentrations might be involved in the progression of NAFLD-cirrhosis toward-HCC. We investigated whether high exogenous copper levels sensitize liver cells to transformation and if it exists an interplay between copper-related proteins and MYC oncogene. NAFLD-cirrhotic patients were characterized by a statistical significant enhancement of serum copper levels, even more evident in HCC patients. We demonstrated that high extracellular copper concentrations increase cell growth, migration, and invasion of liver cancer cells by modulating MYC/CTR1 axis. We highlighted that MYC binds a specific region of the CTR1 promoter, regulating its transcription. Accordingly, CTR1 and MYC proteins expression were progressively up-regulated in liver tissues from NAFLD-cirrhotic to HCC patients. This work provides novel insights on the molecular mechanisms by which copper may favor the progression from cirrhosis to cancer. The Cu/MYC/CTR1 interplay opens a window to refine HCC diagnosis and design new combined therapies.

  9. Copper/MYC/CTR1 interplay: a dangerous relationship in hepatocellular carcinoma

    Science.gov (United States)

    Barbaro, Barbara; Illi, Barbara; Nasi, Sergio; Martini, Maurizio; Licata, Anna; Miele, Luca; Grieco, Antonio; Balsano, Clara

    2018-01-01

    Free serum copper correlates with tumor incidence and progression of human cancers, including hepatocellular carcinoma (HCC). Copper extracellular uptake is provided by the transporter CTR1, whose expression is regulated to avoid excessive intracellular copper entry. Inadequate copper serum concentration is involved in the pathogenesis of Non Alcoholic Fatty Liver Disease (NAFLD), which is becoming a major cause of liver damage progression and HCC incidence. Finally, MYC is over-expressed in most of HCCs and is a critical regulator of cellular growth, tumor invasion and metastasis. The purpose of our study was to understand if higher serum copper concentrations might be involved in the progression of NAFLD-cirrhosis toward-HCC. We investigated whether high exogenous copper levels sensitize liver cells to transformation and if it exists an interplay between copper-related proteins and MYC oncogene. NAFLD-cirrhotic patients were characterized by a statistical significant enhancement of serum copper levels, even more evident in HCC patients. We demonstrated that high extracellular copper concentrations increase cell growth, migration, and invasion of liver cancer cells by modulating MYC/CTR1 axis. We highlighted that MYC binds a specific region of the CTR1 promoter, regulating its transcription. Accordingly, CTR1 and MYC proteins expression were progressively up-regulated in liver tissues from NAFLD-cirrhotic to HCC patients. This work provides novel insights on the molecular mechanisms by which copper may favor the progression from cirrhosis to cancer. The Cu/MYC/CTR1 interplay opens a window to refine HCC diagnosis and design new combined therapies. PMID:29507693

  10. MYC/BCL2/BCL6 triple hit lymphoma: a study of 40 patients with a comparison to MYC/BCL2 and MYC/BCL6 double hit lymphomas.

    Science.gov (United States)

    Huang, Wenting; Medeiros, L Jeffrey; Lin, Pei; Wang, Wei; Tang, Guilin; Khoury, Joseph; Konoplev, Sergej; Yin, C Cameron; Xu, Jie; Oki, Yasuhiro; Li, Shaoying

    2018-05-21

    High-grade B-cell lymphomas with MYC, BCL2, and BCL6 rearrangements (triple hit lymphoma) are uncommon. We studied the clinicopathologic features of 40 patients with triple hit lymphoma and compared them to 157 patients with MYC/BCL2 double hit lymphoma and 13 patients with MYC/BCL6 double hit lymphoma. The triple hit lymphoma group included 25 men and 15 women with a median age of 61 years (range, 34-85). Nine patients had a history of B-cell lymphoma. Histologically, 23 (58%) cases were diffuse large B-cell lymphoma and 17 cases had features of B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma. Most cases of triple hit lymphoma were positive for CD10 (100%), BCL2 (95%), BCL6 (82%), MYC (74%), and 71% with MYC and BCL2 coexpression. P53 was overexpressed in 29% of triple hit lymphoma cases. The clinicopathological features of triple hit lymphoma patients were similar to patients with MYC/BCL2 and MYC/BCL6 double hit lymphoma, except that triple hit lymphoma cases were more often CD10 positive compared with MYC/BCL6 double hit lymphoma (p hit lymphoma and double hit lymphoma and overall survival in triple hit lymphoma patients was 17.6 months, similar to the overall survival of patients with double hit lymphoma (p = 0.67). Patients with triple hit lymphoma showing P53 overexpression had significantly worse overall survival compared with those without P53 overexpression (p = 0.04). On the other hand, double expressor status and prior history of B-cell lymphoma did not correlate with overall survival. In conclusion, most patients with triple hit lymphoma have an aggressive clinical course and poor prognosis and these tumors have a germinal center B-cell immunophenotype, similar to patients with double hit lymphomas. P53 expression is a poor prognostic factor in patients with triple hit lymphoma.

  11. Characterization of cDNAs encoding human leukosialin and localization of the leukosialin gene to chromosome 16

    International Nuclear Information System (INIS)

    Pallant, A.; Eskenazi, A.; Frelinger, J.G.; Mattei, M.G.; Fournier, R.E.K.; Carlsson, S.R.; Fukuda, M.

    1989-01-01

    The authors describe the isolation and characterization of cDNA clones encoding human leukosialin, a major sialoglycoprotein of human leukocytes. Leukosialin is very closely related or identical to the sialophorin molecule, which is involved in T-cell proliferation and whose expression is altered in Wiskott-Aldrich syndrome (WAS), an X-chromosome-linked immunodeficiency disease. Using a rabbit antiserum to leukosialin, a cDNA clone was isolated from a λgt11 cDNA library constructed from human peripheral blood cells. The λgt11 clone was used to isolate longer cDNA clones that correspond to the entire coding sequence of leukosialin. DNA sequence analysis reveals three domains in the predicted mature protein. The extracellular domain is enriched for Ser, Thr, and Pro and contains four contiguous 18-amino acid repeats. The transmembrane and intracellular domains of the human leukosialin molecule are highly homologous to the rat W3/13 molecule. RNA gel blot analysis reveals two polyadenylylated species of 2.3 and 8 kilobases. Southern blot analysis suggests that human leukosialin is a single-copy gene. Analysis of monochromosomal cell hybrids indicates that the leukosialin gene is not X chromosome linked and in situ hybridization shows leukosialin is located on chromosome 16. These findings demonstrate that the primary mutation in WAS is not a defect in the structural gene for leukosialin

  12. Ndrg2 is a PGC-1α/ERRα target gene that controls protein synthesis and expression of contractile-type genes in C2C12 myotubes.

    Science.gov (United States)

    Foletta, Victoria C; Brown, Erin L; Cho, Yoshitake; Snow, Rod J; Kralli, Anastasia; Russell, Aaron P

    2013-12-01

    The stress-responsive, tumor suppressor N-myc downstream-regulated gene 2 (Ndrg2) is highly expressed in striated muscle. In response to anabolic and catabolic signals, Ndrg2 is suppressed and induced, respectively, in mouse C2C12 myotubes. However, little is known about the mechanisms regulating Ndrg2 expression in muscle, as well as the biological role for Ndrg2 in differentiated myotubes. Here, we show that Ndrg2 is a target of a peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α) and estrogen-related receptor alpha (ERRα) transcriptional program and is induced in response to endurance exercise, a physiological stress known also to increase PGC-1α/ERRα activity. Analyses of global gene and protein expression profiles in C2C12 myotubes with reduced levels of NDRG2, suggest that NDRG2 affects muscle growth, contractile properties, MAPK signaling, ion and vesicle transport and oxidative phosphorylation. Indeed, suppression of NDRG2 in myotubes increased protein synthesis and the expression of fast glycolytic myosin heavy chain isoforms, while reducing the expression of embryonic myosin Myh3, other contractile-associated genes and the MAPK p90 RSK1. Conversely, enhanced expression of NDRG2 reduced protein synthesis, and furthermore, partially blocked the increased protein synthesis rates elicited by a constitutively active form of ERRα. In contrast, suppressing or increasing levels of NDRG2 did not affect mRNA expression of genes involved in mitochondrial biogenesis that are regulated by PGC-1α or ERRα. This study shows that in C2C12 myotubes Ndrg2 is a novel PGC-1α/ERRα transcriptional target, which influences protein turnover and the regulation of genes involved in muscle contraction and function. © 2013 Elsevier B.V. All rights reserved.

  13. Cloning and characterization of a novel human zinc finger gene, hKid3, from a C2H2-ZNF enriched human embryonic cDNA library

    International Nuclear Information System (INIS)

    Gao Li; Sun Chong; Qiu Hongling; Liu Hui; Shao Huanjie; Wang Jun; Li Wenxin

    2004-01-01

    To investigate the zinc finger genes involved in human embryonic development, we constructed a C 2 H 2 -ZNF enriched human embryonic cDNA library, from which a novel human gene named hKid3 was identified. The hKid3 cDNA encodes a 554 amino acid protein with an amino-terminal KRAB domain and 11 carboxyl-terminal C 2 H 2 zinc finger motifs. Northern blot analysis indicates that two hKid3 transcripts of 6 and 8.5 kb express in human fetal brain and kidney. The 6 kb transcript can also be detected in human adult brain, heart, and skeletal muscle while the 8.5 kb transcript appears to be embryo-specific. GFP-fused hKid3 protein is localized to nuclei and the ZF domain is necessary and sufficient for nuclear localization. To explore the DNA-binding specificity of hKid3, an oligonucleotide library was selected by GST fusion protein of hKid3 ZF domain, and the consensus core sequence 5'-CCAC-3' was evaluated by competitive electrophoretic mobility shift assay. Moreover, The KRAB domain of hKid3 exhibits transcription repressor activity when tested in GAL4 fusion protein assay. These results indicate that hKid3 may function as a transcription repressor with regulated expression pattern during human development of brain and kidney

  14. Identification of genes potentially regulated by human polynucleotide phosphorylase (hPNPase old-35 using melanoma as a model.

    Directory of Open Access Journals (Sweden)

    Upneet K Sokhi

    Full Text Available Human Polynucleotide Phosphorylase (hPNPase(old-35 or PNPT1 is an evolutionarily conserved 3'→ 5' exoribonuclease implicated in the regulation of numerous physiological processes including maintenance of mitochondrial homeostasis, mtRNA import and aging-associated inflammation. From an RNase perspective, little is known about the RNA or miRNA species it targets for degradation or whose expression it regulates; except for c-myc and miR-221. To further elucidate the functional implications of hPNPase(old-35 in cellular physiology, we knocked-down and overexpressed hPNPase(old-35 in human melanoma cells and performed gene expression analyses to identify differentially expressed transcripts. Ingenuity Pathway Analysis indicated that knockdown of hPNPase(old-35 resulted in significant gene expression changes associated with mitochondrial dysfunction and cholesterol biosynthesis; whereas overexpression of hPNPase(old-35 caused global changes in cell-cycle related functions. Additionally, comparative gene expression analyses between our hPNPase(old-35 knockdown and overexpression datasets allowed us to identify 77 potential "direct" and 61 potential "indirect" targets of hPNPase(old-35 which formed correlated networks enriched for cell-cycle and wound healing functional association, respectively. These results provide a comprehensive database of genes responsive to hPNPase(old-35 expression levels; along with the identification new potential candidate genes offering fresh insight into cellular pathways regulated by PNPT1 and which may be used in the future for possible therapeutic intervention in mitochondrial- or inflammation-associated disease phenotypes.

  15. MYC protein expression is detected in plasma cell myeloma but not in monoclonal gammopathy of undetermined significance (MGUS).

    Science.gov (United States)

    Xiao, Ruobing; Cerny, Jan; Devitt, Katherine; Dresser, Karen; Nath, Rajneesh; Ramanathan, Muthalagu; Rodig, Scott J; Chen, Benjamin J; Woda, Bruce A; Yu, Hongbo

    2014-06-01

    It has been recognized that monoclonal gammopathy of undetermined significance (MGUS) precedes a diagnosis of plasma cell myeloma in most patients. Recent gene expression array analysis has revealed that an MYC activation signature is detected in plasma cell myeloma but not in MGUS. In this study, we performed immunohistochemical studies using membrane CD138 and nuclear MYC double staining on bone marrow biopsies from patients who met the diagnostic criteria of plasma cell myeloma or MGUS. Our study demonstrated nuclear MYC expression in CD138-positive plasma cells in 22 of 26 (84%) plasma cell myeloma samples and in none of the 29 bone marrow samples from patients with MGUS. In addition, our data on the follow-up biopsies from plasma cell myeloma patients with high MYC expression demonstrated that evaluation of MYC expression in plasma cells can be useful in detecting residual disease. We also demonstrated that plasma cells gained MYC expression in 5 of 8 patients (62.5%) when progressing from MGUS to plasma cell myeloma. Analysis of additional lymphomas with plasmacytic differentiation, including lymphoplasmacytic lymphoma, marginal zone lymphoma, and plasmablastic lymphoma, reveals that MYC detection can be a useful tool in the diagnosis of plasma cell myeloma.

  16. Cloning of the cDNA and gene for a human D2 dopamine receptor

    International Nuclear Information System (INIS)

    Grady, D.K.; Makam, H.; Stofko, R.E.; Bunzow, J.R.; Civelli, O.; Marchionni, M.A.; Alfano, M.; Frothingham, L.; Fischer, J.B.; Burke-Howie, K.J.; Server, A.C.

    1989-01-01

    A clone encoding a human D 2 dopamine receptor was isolated from a pituitary cDNA library and sequenced. The deduced protein sequence is 96% identical with that of the cloned rat receptor with one major difference: the human receptor contains an additional 29 amino acids in its putative third cytoplasmic loop. Southern blotting demonstrated the presence of only one human D 2 receptor gene. Two overlapping phage containing the gene were isolated and characterized. DNA sequence analysis of these clones showed that the coding sequence is interrupted by six introns and that the additional amino acids present in the human pituitary receptor are encoded by a single exon of 87 base pairs. The involvement of this sequence in alternative splicing and its biological significance are discussed

  17. Role of trace metals in cell proliferation in the human neuroblastoma: relations with the oncogene N-myc

    International Nuclear Information System (INIS)

    Moretto, Ph.; Michelet, C.; Gouget, B.; Ortega, R.; Sergiant, C.; Llabador, Y.; Simonoff, M.; Benard, J.

    1997-01-01

    Neuroblastoma is one of the most common tumors in young children. Iron is known to be necessary for cellular proliferation. Several studies have suggested that neuroblastoma cells appear to be relatively sensitive to growth inhibition by specific Fe chelators, in vitro. In addition, it appeared that an increased serum ferritin level at diagnosis was associated with a poorer outcome than a normal level. On the other hand it was reported that untreated primary neuroblastoma had multiple copies of the N-myc oncogene. A significant association between genomic amplification and rapid tumor progression after diagnosis has been demonstrated. In order to study the relationship between iron N-myc amplification, we propose to determine the trace metal content of neuroblastoma cells. Preliminary results obtained with two distinct cell lines: SK-N-SH, a neuroblastoma cell line with a single copy of N-myc and IGR-N-91, a metastatic cell line exhibiting 60 copies of N-myc are presented. (authors)

  18. Localization of specific sequences and DNA single-strand breaks in individual UV-A-irradiated human lymphocytes by COMET FISH

    Science.gov (United States)

    Bock, Claudia; Rapp, Alexander; Dittmar, Heike; Monajembashi, Shamci; Greulich, Karl-Otto

    1999-01-01

    The COMET assay, a single cell electrophoresis technique which allows to separate electrophoretically fractionated DNA according to size has been combined with fluorescence in situ hybridization (FISH) which allows to localize specific genes or gene regions. This combination (COMET FISH) allows the detection of DNA single strand breaks in specific regions of the genome of human lymphocytes at the single cell level. Various types of DNA probes, e.g. centromere-, (alpha) - satellite-, telomere-, whole chromosome-, single copy- and region specific DNA probes have been used to investigate whether the UV-A induced DNA single strand breaks are distributed randomly all over the human genome or induced at specific sites ('hot spots'). In the investigated human peripheral blood lymphocytes all but one centromere reveal low sensitivity for UV-A irradiation (500 kJ/m2), while telomeres are randomly distributed over COMET heads and tails. The human chromosome 1 is fractionated by irradiation, but remains in the COMET head, indicating an only moderate degree of fractionation. Among three tested single copy probes, c- myc, p53 and p58, the p53 gene located on chromosome 17p13.1 and the p58 gene (1p36) appear to be located in UV-A stable regions of the human genome in 95% of 65 investigated lymphocytes. In contrast, the c-myc proto-oncogene (8q24) is found in the COMET tail in 90% of the 27 investigated lymphocytes and thus appears to be more sensitive to UV-A irradiation.

  19. Hepatitis C virus core protein targets 4E-BP1 expression and phosphorylation and potentiates Myc-induced liver carcinogenesis in transgenic mice.

    Science.gov (United States)

    Abdallah, Cosette; Lejamtel, Charlène; Benzoubir, Nassima; Battaglia, Serena; Sidahmed-Adrar, Nazha; Desterke, Christophe; Lemasson, Matthieu; Rosenberg, Arielle R; Samuel, Didier; Bréchot, Christian; Pflieger, Delphine; Le Naour, François; Bourgeade, Marie-Françoise

    2017-08-22

    Hepatitis C virus (HCV) is a leading cause of liver diseases including the development of hepatocellular carcinoma (HCC). Particularly, core protein has been involved in HCV-related liver pathologies. However, the impact of HCV core on signaling pathways supporting the genesis of HCC remains largely elusive. To decipher the host cell signaling pathways involved in the oncogenic potential of HCV core, a global quantitative phosphoproteomic approach was carried out. This study shed light on novel differentially phosphorylated proteins, in particular several components involved in translation. Among the eukaryotic initiation factors that govern the translational machinery, 4E-BP1 represents a master regulator of protein synthesis that is associated with the development and progression of cancers due to its ability to increase protein expression of oncogenic pathways. Enhanced levels of 4E-BP1 in non-modified and phosphorylated forms were validated in human hepatoma cells and in mouse primary hepatocytes expressing HCV core, in the livers of HCV core transgenic mice as well as in HCV-infected human primary hepatocytes. The contribution of HCV core in carcinogenesis and the status of 4E-BP1 expression and phosphorylation were studied in HCV core/Myc double transgenic mice. HCV core increased the levels of 4E-BP1 expression and phosphorylation and significantly accelerated the onset of Myc-induced tumorigenesis in these double transgenic mice. These results reveal a novel function of HCV core in liver carcinogenesis potentiation. They position 4E-BP1 as a tumor-specific target of HCV core and support the involvement of the 4E-BP1/eIF4E axis in hepatocarcinogenesis.

  20. LeMYC2 acts as a negative regulator of blue light mediated photomorphogenic growth, and promotes the growth of adult tomato plants

    Science.gov (United States)

    2014-01-01

    Background Arabidopsis ZBF1/MYC2bHLH transcription factor is a repressor of photomorphogenesis, and acts as a point of cross talk in light, abscisic acid (ABA) and jasmonic acid (JA) signaling pathways. MYC2 also functions as a positive regulator of lateral root development and flowering time under long day conditions. However, the function of MYC2 in growth and development remains unknown in crop plants. Results Here, we report the functional analyses of LeMYC2 in tomato (Lycopersicon esculentum). The amino acid sequence of LeMYC2 showed extensive homology with Arabidopsis MYC2, containing the conserved bHLH domain. To study the function of LeMYC2 in tomato, overexpression and RNA interference (RNAi) LeMYC2 tomato transgenic plants were generated. Examination of seedling morphology, physiological responses and light regulated gene expression has revealed that LeMYC2 works as a negative regulator of blue light mediated photomorphogenesis. Furthermore, LeMYC2 specifically binds to the G-box of LeRBCS-3A promoter. Overexpression of LeMYC2 has led to increased root length with more number of lateral roots. The tomato plants overexpressing LeMYC2 have reduced internode distance with more branches, and display the opposite morphology to RNAi transgenic lines. Furthermore, this study shows that LeMYC2 promotes ABA and JA responsiveness. Conclusions Collectively, this study highlights that working in light, ABA and JA signaling pathways LeMYC2 works as an important regulator for growth and development in tomato plants. PMID:24483714

  1. MYC Amplification as a Predictive Factor of Complete Pathologic Response to Docetaxel-based Neoadjuvant Chemotherapy for Breast Cancer.

    Science.gov (United States)

    Pereira, Cynthia Brito Lins; Leal, Mariana Ferreira; Abdelhay, Eliana Saul Furquim Werneck; Demachki, Sâmia; Assumpção, Paulo Pimentel; de Souza, Mirian Carvalho; Moreira-Nunes, Caroline Aquino; Tanaka, Adriana Michiko da Silva; Smith, Marília Cardoso; Burbano, Rommel Rodríguez

    2017-06-01

    Neoadjuvant chemotherapy is a standard treatment for stage II and III breast cancer. The identification of biomarkers that may help in the prediction of response to neoadjuvant therapies is necessary for a more precise definition of the best drug or drug combination to induce a better response. We assessed the role of Ki67, hormone receptors expression, HER2, MYC genes and their protein status, and KRAS codon 12 mutations as predictor factors of pathologic response to anthracycline-cyclophosphamide (AC) followed by taxane docetaxel (T) neoadjuvant chemotherapy (AC+T regimen) in 51 patients with invasive ductal breast cancer. After neoadjuvant chemotherapy, 82.4% of patients showed pathologic partial response, with only 9.8% showing pathologic complete response. In multivariate analysis, MYC immunoreactivity and high MYC gain defined as MYC/nucleus ≥ 5 were significant predictor factors for pathologic partial response. Using the receiver operating characteristic curve analysis, the ratio of 2.5 MYC/CEP8 (sensitivity of 80% and specificity of 89.1%) or 7 MYC/nuclei copies (sensitivity of 80% and specificity of 73.9%) as the best cutoff in predicting a pathologic complete response was identified. Thus, MYC may have a role in chemosensitivity to AC and/or docetaxel drugs. Additionally, MYC amplification may be a predictor factor of pathologic response to the AC+T regimen in patients with breast cancer. Moreover, patients with an increased number of MYC copies showed pathologic complete response to this neoadjuvant treatment more frequently. The analysis of MYC amplification may help in the identification of patients that may have a better response to AC+T treatment. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Unexpected detection of porcine rotavirus C strains carrying human origin VP6 gene.

    Science.gov (United States)

    Kattoor, Jobin Jose; Saurabh, Sharad; Malik, Yashpal Singh; Sircar, Shubhankar; Dhama, Kuldeep; Ghosh, Souvik; Bányai, Krisztián; Kobayashi, Nobumichi; Singh, Raj Kumar

    2017-12-01

    Rotavirus C (RVC), a known etiological agent of diarrheal outbreaks, mainly inflicts swine population globally with sporadic incidence in human, cattle, ferret, mink and dog. To demonstrate the presence of RVC in Indian swine population and characterization of its selected structural (VP6) and non-structural (NSP4 and NSP5) genes. A total of 108 diarrheic samples from different regions of India were used. Isolated RNA was loaded onto polyacrylamide gel to screen for the presence of RVs through the identification of specific electrophoretic genomic migration pattern. To characterize the RVC strains, VP6 gene and NSP4 and NSP5 genes were amplified, sequenced and analyzed. Based on VP6 gene specific diagnostic RT-PCR, the presence of RVC was confirmed in 12.0% (13/108) piglet fecal specimens. The nucleotide sequence analysis of VP6 gene, encoding inner capsid protein, from selected porcine RVC (PoRVC) strains revealed more than 93% homologies to human RVC strains (HuRVC) of Eurasian origin. These strains were distant from hitherto reported PoRVCs and clustered with HuRVCs, owning I2 genotype. However, the two non-structural genes, i.e. NSP4 and NSP5, of these strains were found to be of swine type, signifying a re-assortment event that has occurred in the Indian swine population. The findings indicate the presence of human-like RVC in Indian pigs and division of RVC clade with I2 genotype into further sub-clades. To the best of our knowledge, this appears to be the first report of RVC in Indian swine population. Incidence of human-like RVC VP6 gene in swine supports its subsequent zoonotic prospective.

  3. Investigating the Role of the Post-transcriptional Gene Regulator MiR-24-3p in the Proliferation, Migration and Apoptosis of Human Arterial Smooth Muscle Cells in Arteriosclerosis Obliterans

    Directory of Open Access Journals (Sweden)

    Xiao-feng Zhu

    2015-07-01

    Full Text Available Aims: To explore the expression of miR-24-3p in human arteries with arteriosclerosis obliterans (ASO as well as the role of miR-24-3p in the pathogenesis of ASO. Methods: We used quantitative real-time PCR (qRT-PCR and in situ hybridization to monitor miR-24-3p expression in human arteries. To investigate the effect of miR-24-3p on human arterial smooth muscle cells (HASMCs, we applied cell counting and EdU assays to monitor proliferation and transwell and wound healing assays to investigate migration and flow cytometry to investigate apoptosis. Furthermore, we applied 3'-untranslated region (3'-UTR luciferase assays to investigate the role of miR-24-3p in targeting platelet-derived growth factor receptor B (PDGFRB and c-Myc. Results: MiR-24-3p was mainly located in the media of arteries and was downregulated in ASO arteries compared with normal arteries. Platelet-derived growth factor BB (PDGF-BB treatment reduced the expression of miR-24-3p in primary cultured HASMCs. MiR-24-3p mimic oligos inhibited the proliferation and migration, and promotes apoptosis of HASMCs. Our 3'-UTR luciferase assays confirmed that PDGFRB and c-Myc were targets of miR-24-3p. Conclusion: The results suggest that miR-24-3p regulates the proliferation and migration of HASMCs by targeting PDGFRB and c-Myc. The PDGF/miR-24-3p/PDGFRB and PDGF/miR-24-3p/c-Myc pathways may play critical roles in the pathogenesis of ASO. These findings highlight the potential for new therapeutic targets for ASO.

  4. Loss of PRDM11 promotes MYC-driven lymphomagenesis

    DEFF Research Database (Denmark)

    Fog-Tonnesen, Cathrine Kolster; Asmar, Fazila; Côme, Christophe Roger Michel

    2015-01-01

    of the previously uncharacterized PR-domain family member Prdm11 and overexpression of MYC. Overexpression of PRDM11 inhibits proliferation and induces apoptosis. Prdm11 knockout mice are viable, and loss of Prdm11 accelerates MYC-driven lymphomagenesis in the Eµ-Myc mouse model. Moreover, we show that patients...

  5. Expression Analysis of p16, c-Myc, and mSin3A in Non-small Cell Lung Cancer by Computer Aided Scoring and Analysis (CASA).

    Science.gov (United States)

    Salmaninejad, Arash; Estiar, Mehrdad Asghari; Gill, Rajbir K; Shih, Joanna H; Hewitt, Stephen; Jeon, Hyo-Sung; Fukuoka, Junya; Shilo, Konstantin; Shakoori, Abbas; Jen, Jin

    2015-01-01

    Immunohistochemical analysis (IHC) of tissue microarray (TMA) slides enables large sets of tissue samples to be analyzed simultaneously on a single slide. However, manual evaluation of small cores on a TMA slide is time consuming and error prone. We describe a computer aided scoring and analysis (CASA) method to allow facile and reliable scoring of IHC staining using TMA containing 300 non-small cell lung cancer (NSCLC) cases. In the two previous published papers utilizing our TMA slides of lung cancer we examined 18 proteins involved in the chromatin machinery. We developed our study using more proteins of the chromatin complex and several transcription factors that facilitate the chromatin machinery. Then, a total of 78 antibodies were evaluated by CASA to derive a normalized intensity value that correlated with the overall staining status of the targeting protein. The intensity values for TMA cores were then examined for association to clinical variables and predictive significance individually and with other factors. RESULTs: Using our TMA, the intensity of several protein pairs were significantly correlated with an increased risk of death in NSCLC. These included c-Myc with p16, mSin3A with p16 and c-Myc with mSinA. Predictive values of these pairs remained significant when evaluated based on standard IHC scores. Our results demonstrate the usefulness of CASA as a valuable tool for systematic assessment of TMA slides to identify potential predictive biomarkers using a large set of primary human tissues.

  6. Organization of the gene coding for human protein C inhibitor (plasminogen activator inhibitor-3). Assignment of the gene to chromosome 14

    NARCIS (Netherlands)

    Meijers, J. C.; Chung, D. W.

    1991-01-01

    Protein C inhibitor (plasminogen activator inhibitor-3) is a plasma glycoprotein and a member of the serine proteinase inhibitor superfamily. In the present study, the human gene for protein C inhibitor was isolated and characterized from three independent phage that contained overlapping inserts

  7. Molecular analysis of human complement component C5: localization of the structural gene to chromosome 9

    International Nuclear Information System (INIS)

    Wetsel, R.A.; Lemons, R.S.; Le Beau, M.M.; Barnum, S.R.; Noack, D.; Tack, B.F.

    1988-01-01

    A human C5 clone (pC5HG2) was isolated from a cDNA library constructed from Hep G2 mRNA. he DNA sequence showed that the pC5HG2 insert was comprised of 3309 base pairs of pro-C5 coding sequence and 404 base pairs of 3'-untranslated sequence. The derived amino acid sequence contained the entire coding sequence of the C5 α-chain, the β-α-chain junction region, and 100 amino acids (approximately 50%) of the β-chain. Protein sequences of four C5 tryptic peptides were aligned exactly to this sequence and demonstrated that C5 synthesized and secreted by Hep G2 cells is probably identical with plasma-derived C5. Coding sequence alignment of the human C5 sequences with those of murine C5 indicated that 80% of the nucleotides and 79% of the amino acids were placed identically in the two species. Amino acid sequence alignment of the homologous family members C3, C4, and α 2 -macroglobulin with that of C5 demonstrated 27%, 25%, and 19% identity, respectively. As was found in murine C5, the corresponding thiol ester region of human C5 contained several conserved amino acids, but the critical cysteine and glutamine residues which give rise to the intramolecular thiol ester bond in C3, C4, and α 2 -macroglobulin were absent in C5, having been replaced by serine and alanine, respectively. With the use of a panel of hamster-human somatic cell hybrids, the C5 gene was mapped to human chromosome 9. In situ chromosomal hybridization studies employing metaphase cells further localized the gene to bands 9q32-34, with the largest cluster of grains at 9q34.1

  8. AKT1, LKB1, and YAP1 revealed as MYC interactors with NanoLuc-based protein-fragment complementation assay. | Office of Cancer Genomics

    Science.gov (United States)

    The c-Myc (MYC) transcription factor is a major cancer driver and a well-validated therapeutic target. However, directly targeting MYC has been challenging. Thus, identifying proteins that interact with and regulate MYC may provide alternative strategies to inhibit its oncogenic activity. Here we report the development of a NanoLuc®-based protein-fragment complementation assay (NanoPCA) and mapping of the MYC protein interaction hub in live mammalian cells.

  9. Localisation of lung cancer by a radiolabelled monoclonal antibody against the c-myc oncogene product

    Energy Technology Data Exchange (ETDEWEB)

    Chan, S Y.T.; Evan, G I; Ritson, A; Watson, J; Wraight, P; Sikora, K

    1986-11-01

    A set of mouse monoclonal antibodies against the c-myc oncogene product, a 62,000 dalton nuclear binding protein involved in cell cycle control, has been constructed by immunisation with synthetic peptide fragments. One such antibody, CT14, was radiolabelled with /sup 131/I and administered to 20 patients with different malignant diseases. Good tumour localisation was observed in 12 out of 14 patients with primary bronchial carcinoma but not in patients with pulmonary metastases from primary tumours elsewhere. Successfully localised tumours were all 3 cm or more in diameter. Monoclonal antibodies against oncogene products may provide novel selective tools for the diagnosis and therapy of cancer.

  10. Primary central nervous system diffuse large B-cell lymphoma shows an activated B-cell-like phenotype with co-expression of C-MYC, BCL-2, and BCL-6.

    Science.gov (United States)

    Li, Xiaomei; Huang, Ying; Bi, Chengfeng; Yuan, Ji; He, Hong; Zhang, Hong; Yu, QiuBo; Fu, Kai; Li, Dan

    2017-06-01

    Diffuse large B-cell lymphoma (DLBCL) is the most common non-Hodgkin lymphoma, whose main prognostic factor is closely related to germinal center B-cell-like subtype (GCB- DLBCL) or activated B-cell-like type (non-GCB-DLBCL). The most common type of primary central nervous system lymphoma is diffuse large B-cell type with poor prognosis and the reason is unclear. This study aims to stratify primary central nervous system diffuse large B-cell lymphoma (PCNS-DLBCL) according to the cell-of-origin (COO) and to investigate the multiple proteins expression of C-MYC, BCL-6, BCL-2, TP53, further to elucidate the reason why primary central nervous system diffuse large B-cell lymphoma possesses a poor clinical outcome as well. Nineteen cases of primary central nervous system DLBCL were stratified according to immunostaining algorithms of Hans, Choi and Meyer (Tally) and we investigated the multiple proteins expression of C-MYC, BCL-6, BCL-2, TP53. The Epstein-Barr virus and Borna disease virus infection were also detected. Among nineteen cases, most (15-17 cases) were assigned to the activated B-cell-like subtype, highly expression of C-MYC (15 cases, 78.9%), BCL-2 (10 cases, 52.6%), BCL-6 (15 cases, 78.9%). Unfortunately, two cases were positive for PD-L1 while PD-L2 was not expressed in any case. Two cases infected with BDV but no one infected with EBV. In conclusion, most primary central nervous system DLBCLs show an activated B-cell-like subtype characteristic and have multiple expressions of C-MYC, BCL-2, BCL-6 protein, these features might be significant factor to predict the outcome and guide treatment of PCNS-DLBCLs. Copyright © 2017 Elsevier GmbH. All rights reserved.

  11. MUC1-C activates polycomb repressive complexes and downregulates tumor suppressor genes in human cancer cells.

    Science.gov (United States)

    Rajabi, Hasan; Hiraki, Masayuki; Kufe, Donald

    2018-04-01

    The PRC2 and PRC1 complexes are aberrantly expressed in human cancers and have been linked to decreases in patient survival. MUC1-C is an oncoprotein that is also overexpressed in diverse human cancers and is associated with a poor prognosis. Recent studies have supported a previously unreported function for MUC1-C in activating PRC2 and PRC1 in cancer cells. In the regulation of PRC2, MUC1-C (i) drives transcription of the EZH2 gene, (ii) binds directly to EZH2, and (iii) enhances occupancy of EZH2 on target gene promoters with an increase in H3K27 trimethylation. Regarding PRC1, which is recruited to PRC2 sites in the hierarchical model, MUC1-C induces BMI1 transcription, forms a complex with BMI1, and promotes H2A ubiquitylation. MUC1-C thereby contributes to the integration of PRC2 and PRC1-mediated repression of tumor suppressor genes, such as CDH1, CDKN2A, PTEN and BRCA1. Like PRC2 and PRC1, MUC1-C is associated with the epithelial-mesenchymal transition (EMT) program, cancer stem cell (CSC) state, and acquisition of anticancer drug resistance. In concert with these observations, targeting MUC1-C downregulates EZH2 and BMI1, inhibits EMT and the CSC state, and reverses drug resistance. These findings emphasize the significance of MUC1-C as a therapeutic target for inhibiting aberrant PRC function and reprogramming the epigenome in human cancers.

  12. Cooperative action of multiple cis-acting elements is required for N-myc expression in branchial arches: specific contribution of GATA3.

    Science.gov (United States)

    Potvin, Eric; Beuret, Laurent; Cadrin-Girard, Jean-François; Carter, Marcelle; Roy, Sophie; Tremblay, Michel; Charron, Jean

    2010-11-01

    The precise expression of the N-myc proto-oncogene is essential for normal mammalian development, whereas altered N-myc gene regulation is known to be a determinant factor in tumor formation. Using transgenic mouse embryos, we show that N-myc sequences from kb -8.7 to kb +7.2 are sufficient to reproduce the N-myc embryonic expression profile in developing branchial arches and limb buds. These sequences encompass several regulatory elements dispersed throughout the N-myc locus, including an upstream limb bud enhancer, a downstream somite enhancer, a branchial arch enhancer in the second intron, and a negative regulatory element in the first intron. N-myc expression in the limb buds is under the dominant control of the limb bud enhancer. The expression in the branchial arches necessitates the interplay of three regulatory domains. The branchial arch enhancer cooperates with the somite enhancer region to prevent an inhibitory activity contained in the first intron. The characterization of the branchial arch enhancer has revealed a specific role of the transcription factor GATA3 in the regulation of N-myc expression. Together, these data demonstrate that correct N-myc developmental expression is achieved via cooperation of multiple positive and negative regulatory elements.

  13. SOX2 and SOX2-MYC Reprogramming Process of Fibroblasts to the Neural Stem Cells Compromised by Senescence.

    Directory of Open Access Journals (Sweden)

    Marta Winiecka-Klimek

    Full Text Available Tumorigenic potential of induced pluripotent stem cells (iPSCs infiltrating population of induced neural stem cells (iNSCs generated from iPSCs may limit their medical applications. To overcome such a difficulty, direct reprogramming of adult somatic cells into iNSCs was proposed. The aim of this study was the systematic comparison of induced neural cells (iNc obtained with different methods-direct reprogramming of human adult fibroblasts with either SOX2 (SiNSc-like or SOX2 and c-MYC (SMiNSc-like and induced pluripotent stem cells differentiation to ebiNSc-in terms of gene expression profile, differentiation potential as well as proliferation properties. Immunocytochemistry and real-time PCR analyses were used to evaluate gene expression profile and differentiation potential of various iNc types. Bromodeoxyuridine (BrdU incorporation and senescence-associated beta-galactosidase (SA-β-gal assays were used to estimate proliferation potential. All three types of iNc were capable of neuronal differentiation; however, astrocytic differentiation was possible only in case of ebiNSc. Contrary to ebiNSc generation, the direct reprogramming was rarely a propitious process, despite 100% transduction efficiency. The potency of direct iNSCs-like cells generation was lower as compared to iNSCs obtained by iPSCs differentiation, and only slightly improved when c-MYC was added. Directly reprogrammed iNSCs-like cells were lacking the ability to differentiate into astrocytic cells and characterized by poor efficiency of neuronal cells formation. Such features indicated that these cells could not be fully reprogrammed, as confirmed mainly with senescence detection. Importantly, SiNSc-like and SMiNSc-like cells were unable to achieve the long-term survival and became senescent, which limits their possible therapeutic applicability. Our results suggest that iNSCs-like cells, generated in the direct reprogramming attempts, were either not fully reprogrammed or

  14. Cloning of the cDNA for a human homologue of the Drosophila white gene and mapping to chromosome 21q22.3.

    OpenAIRE

    Chen, H.; Rossier, C.; Lalioti, M. D.; Lynn, A.; Chakravarti, A.; Perrin, G.; Antonarakis, S. E.

    1996-01-01

    In an effort to contribute to the transcript map of human chromosome 21 and the understanding of the pathophysiology of trisomy 21, we have used exon trapping to identify fragments of chromosome 21 genes. Two trapped exons, from pools of chromosome 21-specific cosmids, showed homology to the Drosophila white (w) gene. We subsequently cloned the corresponding cDNA for a human homologue of the Drosophila w gene (hW) from human retina and fetal brain cDNA libraries. The gene belongs to the ATP-b...

  15. Serine 62-Phosphorylated MYC Associates with Nuclear Lamins and Its Regulation by CIP2A Is Essential for Regenerative Proliferation

    Directory of Open Access Journals (Sweden)

    Kevin Myant

    2015-08-01

    Full Text Available An understanding of the mechanisms determining MYC’s transcriptional and proliferation-promoting activities in vivo could facilitate approaches for MYC targeting. However, post-translational mechanisms that control MYC function in vivo are poorly understood. Here, we demonstrate that MYC phosphorylation at serine 62 enhances MYC accumulation on Lamin A/C-associated nuclear structures and that the protein phosphatase 2A (PP2A inhibitor protein CIP2A is required for this process. CIP2A is also critical for serum-induced MYC phosphorylation and for MYC-elicited proliferation induction in vitro. Complementary transgenic approaches and an intestinal regeneration model further demonstrated the in vivo importance of CIP2A and serine 62 phosphorylation for MYC activity upon DNA damage. However, targeting of CIP2A did not influence the normal function of intestinal crypt cells. These data underline the importance of nuclear organization in the regulation of MYC phosphorylation, leading to an in vivo demonstration of a strategy for inhibiting MYC activity without detrimental physiological effects.

  16. Epithelial-to-mesenchymal transition and c-myc expression are the determinants of cetuximab-induced enhancement of squamous cell carcinoma radioresponse

    International Nuclear Information System (INIS)

    Skvortsova, Ira; Skvortsov, Sergej; Raju, Uma; Stasyk, Taras; Riesterer, Oliver; Schottdorf, Eva-Maria; Popper, Bela-Andre; Schiestl, Bernhard; Eichberger, Paul; Debbage, Paul; Neher, Andreas; Bonn, Guenther K.; Huber, Lukas A.; Milas, Luka; Lukas, Peter

    2010-01-01

    Purpose: Radiation therapy cures malignant tumors of the head and neck region more effectively when it is combined with application of the anti-EGFR monoclonal antibody cetuximab. Despite the successes achieved, we still do not know how to select patients who will respond to this combination of anti-EGFR monoclonal antibody and radiation. This study was conducted to elucidate possible mechanisms which cause the combined treatment with cetuximab and irradiation to fail in some cases of squamous cell carcinomas. Methods and materials: Mice bearing FaDu and A431 squamous cell carcinoma xenograft tumors were treated with cetuximab (total dose 3 mg, intraperitoneally), irradiation (10 Gy) or their combination at the same doses. Treatment was applied when tumors reached 8 mm in size. To collect samples for further protein analysis (two-dimensional differential gel electrophoresis (2-D DIGE), mass spectrometry MALDI-TOF/TOF, Western blot analysis, and ELISA), mice from each group were sacrificed on the 8th day after the first injection of cetuximab. Other mice were subjected to tumor growth delay assay. Results: In FaDu xenografts, treatment with cetuximab alone was nearly as effective as cetuximab combined with ionizing radiation, whereas A431 tumors responded to the combined treatment with significantly enhanced delay in tumor growth. Tumors extracted from the untreated FaDu and A431 xenografts were analysed for protein expression, and 34 proteins that were differently expressed in the two tumor types were identified. The majority of these proteins are closely related to intratumoral angiogenesis, cell adhesion, motility, differentiation, epithelial-to-mesenchymal transition (EMT), c-myc signaling and DNA repair. Conclusions: The failure of cetuximab to enhance radiation response in FaDu xenografts was associated with the initiation of the program of EMT and with c-myc up-regulation in the carcinoma cells. For this reason, c-myc and EMT-related proteins (E

  17. Incorporating genomic, transcriptomic and clinical data: a prognostic and stem cell-like MYC and PRC imbalance in high-risk neuroblastoma.

    Science.gov (United States)

    Yang, Xinan Holly; Tang, Fangming; Shin, Jisu; Cunningham, John M

    2017-10-03

    Previous studies suggested that cancer cells possess traits reminiscent of the biological mechanisms ascribed to normal embryonic stem cells (ESCs) regulated by MYC and Polycomb repressive complex 2 (PRC2). Several poorly differentiated adult tumors showed preferentially high expression levels in targets of MYC, coincident with low expression levels in targets of PRC2. This paper will reveal this ESC-like cancer signature in high-risk neuroblastoma (HR-NB), the most common extracranial solid tumor in children. We systematically assembled genomic variants, gene expression changes, priori knowledge of gene functions, and clinical outcomes to identify prognostic multigene signatures. First, we assigned a new, individualized prognostic index using the relative expressions between the poor- and good-outcome signature genes. We then characterized HR-NB aggressiveness beyond these prognostic multigene signatures through the imbalanced effects of MYC and PRC2 signaling. We further analyzed Retinoic acid (RA)-induced HR-NB cells to model tumor cell differentiation. Finally, we performed in vitro validation on ZFHX3, a cell differentiation marker silenced by PRC2, and compared cell morphology changes before and after blocking PRC2 in HR-NB cells. A significant concurrence existed between exons with verified variants and genes showing MYCN-dependent expression in HR-NB. From these biomarker candidates, we identified two novel prognostic gene-set pairs with multi-scale oncogenic defects. Intriguingly, MYC targets over-represented an unfavorable component of the identified prognostic signatures while PRC2 targets over-represented a favorable component. The cell cycle arrest and neuronal differentiation marker ZFHX3 was identified as one of PRC2-silenced tumor suppressor candidates. Blocking PRC2 reduced tumor cell growth and increased the mRNA expression levels of ZFHX3 in an early treatment stage. This hypothesis-driven systems bioinformatics work offered novel insights into

  18. MYC-induced nuclear antigen (MINA) and preeclampsia.

    Science.gov (United States)

    Martinez-Fierro, Margarita L; Reyes-Oliva, Edwin A; Cabral-Pacheco, Griselda A; Garza-Veloz, Idalia; Aceves-Medina, Maria C; Luevano, Martha; Barbosa-Cisneros, Olga Y; Galvan-Valencia, Marisol; Yahuaca-Mendoza, Patricia; Delgado-Enciso, Ivan; Zamudio-Osuna, Michelle; Rodriguez-Sanchez, Iram P; Vazquez-Castro, Rosbel; Guerrero-Saucedo, Marycruz

    2016-05-01

    Inadequate trophoblast invasion and the subsequent inflammatory response have been implicated in preeclampsia (PE) pathogenesis. Because MYC-induced nuclear antigen (MINA) gene expression is involved in cell proliferation and differentiation, inflammatory response modulation, and the unpaired regulation of which is associated with human diseases, we sought to investigate the connection between MINA and PE. The aim of this study was to evaluate the possible relationship between the MINA rs4857304 variant and susceptibility to PE development as well as to estimate placental MINA gene expression and its association with PE. About 242 pregnant women (126 PE cases and 116 controls) were included. MINA genotyping and gene expression were evaluated by quantitative real-time polymerase chain reaction using TaqMan probes. The G/G genotype of the MINA rs4857304 variant was associated with severe PE (p = 0.027, OR = 1.8, 95% CI = 1.8-3.2). Carriers of one G allele of the MINA rs4857304 variant exhibited a 1.7-fold increased risk of severe PE (p = 0.029, 95% CI = 1.1-3.0). MINA was underexpressed in preeclamptic placentas and MINA expression differed between the mild and severe PE groups. Differences in the expression levels of MINA were found among women with the T/T genotype of the rs4857304 polymorphism and carriers of at least one G allele (p = 0.024). PE and its severity are associated with the underexpression of placental MINA, and the G/G genotype of the MINA rs4857304 variant may modify the risk of severe PE among the PE cases evaluated.

  19. A microRNA-mediated regulatory loop modulates NOTCH and MYC oncogenic signals in B- and T-cell malignancies.

    Science.gov (United States)

    Ortega, M; Bhatnagar, H; Lin, A-P; Wang, L; Aster, J C; Sill, H; Aguiar, R C T

    2015-04-01

    Growing evidence suggests that microRNAs (miRNAs) facilitate the cross-talk between transcriptional modules and signal transduction pathways. MYC and NOTCH1 contribute to the pathogenesis of lymphoid malignancies. NOTCH induces MYC, connecting two signaling programs that enhance oncogenicity. Here we show that this relationship is bidirectional and that MYC, via a miRNA intermediary, modulates NOTCH. MicroRNA-30a (miR-30a), a member of a family of miRNAs that are transcriptionally suppressed by MYC, directly binds to and inhibits NOTCH1 and NOTCH2 expression. Using a murine model and genetically modified human cell lines, we confirmed that miR-30a influences NOTCH expression in a MYC-dependent fashion. In turn, through genetic modulation, we demonstrated that intracellular NOTCH1 and NOTCH2, by inducing MYC, suppressed miR-30a. Conversely, pharmacological inhibition of NOTCH decreased MYC expression and ultimately de-repressed miR-30a. Examination of genetic models of gain and loss of miR-30a in diffuse large B-cell lymphoma (DLBCL) and T-acute lymphoblastic leukemia (T-ALL) cells suggested a tumor-suppressive role for this miRNA. Finally, the activity of the miR-30a-NOTCH-MYC loop was validated in primary DLBCL and T-ALL samples. These data define the presence of a miRNA-mediated regulatory circuitry that may modulate the oncogenic signals originating from NOTCH and MYC.

  20. Radiation-induced transformation in oncogene primed C3H/10T1/2 cells; a new system for analysis of multi-step transformation in vitro

    International Nuclear Information System (INIS)

    Drozdoff, V.V.

    1988-01-01

    Several established rodent cell lines, such as C3H/10T1/2 fibroblasts, have been developed to study radiation and chemically-induced malignant transformation. Most experimental evidence has supported the idea that transformation in 10T1/2 cells involved at least two steps but that the apparent frequency of transformation depends on the density of plated cells. A new approach is presented here for studying radiation-induced transformation. An oncogene primed cell system (C3H-myc) was developed by introducing a constitutively active mouse c-myc gene into 10T1/2 cells. A primary goal was to determine if the introduction of an activated oncogene could substitute for one of the required steps in radiation-induced transformation. Results are presented that show that the expression of the exogenous myc gene significantly increased the frequency of radiation-induced transformation in these cells. Subculture experiments performed to analyze the kinetics of transformation in C3H-myc cells and reconstruction experiments allowing the effects of normal cells on radiation-induced transformants to be determined indicated that transformed cells arose very shortly after irradiation. These results support the conclusion that a radiation-induced event can complement the effect of myc in C3H-myc cells and directly result in transformation. This system thus provides an opportunity to isolate early steps in radiation-induced transformation and should facilitate the identification and analysis of these events

  1. MYC and the Control of DNA Replication

    Science.gov (United States)

    Dominguez-Sola, David; Gautier, Jean

    2014-01-01

    The MYC oncogene is a multifunctional protein that is aberrantly expressed in a significant fraction of tumors from diverse tissue origins. Because of its multifunctional nature, it has been difficult to delineate the exact contributions of MYC’s diverse roles to tumorigenesis. Here, we review the normal role of MYC in regulating DNA replication as well as its ability to generate DNA replication stress when overexpressed. Finally, we discuss the possible mechanisms by which replication stress induced by aberrant MYC expression could contribute to genomic instability and cancer. PMID:24890833

  2. Activation of the Tor/Myc signaling axis in intestinal stem and progenitor cells affects longevity, stress resistance and metabolism in drosophila.

    Science.gov (United States)

    Strilbytska, Olha M; Semaniuk, Uliana V; Storey, Kenneth B; Edgar, Bruce A; Lushchak, Oleh V

    2017-01-01

    The TOR (target of rapamycin) signaling pathway and the transcriptional factor Myc play important roles in growth control. Myc acts, in part, as a downstream target of TOR to regulate the activity and functioning of stem cells. Here we explore the role of TOR-Myc axis in stem and progenitor cells in the regulation of lifespan, stress resistance and metabolism in Drosophila. We found that both overexpression of rheb and myc-rheb in midgut stem and progenitor cells decreased the lifespan and starvation resistance of flies. TOR activation caused higher survival under malnutrition conditions. Furthermore, we demonstrate gut-specific activation of JAK/STAT and insulin signaling pathways to control gut integrity. Both genetic manipulations had an impact on carbohydrate metabolism and transcriptional levels of metabolic genes. Our findings indicate that activation of the TOR-Myc axis in midgut stem and progenitor cells influences a variety of traits in Drosophila. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Differences in TCDD-elicited gene expression profiles in human HepG2, mouse Hepa1c1c7 and rat H4IIE hepatoma cells

    Directory of Open Access Journals (Sweden)

    Burgoon Lyle D

    2011-04-01

    Full Text Available Abstract Background 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD is an environmental contaminant that elicits a broad spectrum of toxic effects in a species-specific manner. Current risk assessment practices routinely extrapolate results from in vivo and in vitro rodent models to assess human risk. In order to further investigate the species-specific responses elicited by TCDD, temporal gene expression responses in human HepG2, mouse Hepa1c1c7 and rat H4IIE cells were compared. Results Microarray analysis identified a core set of conserved gene expression responses across species consistent with the role of AhR in mediating adaptive metabolic responses. However, significant species-specific as well as species-divergent responses were identified. Computational analysis of the regulatory regions of species-specific and -divergent responses suggests that dioxin response elements (DREs are involved. These results are consistent with in vivo rat vs. mouse species-specific differential gene expression, and more comprehensive comparative DRE searches. Conclusions Comparative analysis of human HepG2, mouse Hepa1c1c7 and rat H4IIE TCDD-elicited gene expression responses is consistent with in vivo rat-mouse comparative gene expression studies, and more comprehensive comparative DRE searches, suggesting that AhR-mediated gene expression is species-specific.

  4. Overexpression of SmMYC2 Increases the Production of Phenolic Acids in Salvia miltiorrhiza

    Directory of Open Access Journals (Sweden)

    Na Yang

    2017-10-01

    Full Text Available MYC2 is a core transcription factor in the plant response to jasmonates. It also functions in secondary metabolism and various processes for growth and development. However, the knowledge about its role in Salvia miltiorrhiza is still very limited. We determined that the biosynthesis of salvianolic acid B (Sal B was strongly induced in 2-month-old transgenic plants that over-expressed SmMYC2. In the roots of transgenic line 12 that over-expressed SmMYC2 (OEM-12, the Sal B concentration was as high as 5.95 ± 0.07 mg g-1, a level that was 1.88-fold higher than that in control plants that had been transformed with an empty vector. Neither tanshinone IIA nor cryptotanshinone was detected by high-performance liquid chromatography in any of the genotypes. Global transcriptomic analysis using RNA sequencing revealed that most enzyme-encoding genes for the phenylpropanoid biosynthesis pathway were up-regulated in the overexpression lines. Furthermore, both the phenylalanine and tyrosine biosynthesis pathways were activated in those transgenics. Our data demonstrate that overexpression of SmMYC2 promotes the production of phenolic acids by simultaneously activating both primary and secondary pathways for metabolism in S. miltiorrhiza.

  5. Myc Decoy Oligodeoxynucleotide Inhibits Growth and Modulates Differentiation of Mouse Embryonic Stem Cells as a Model of Cancer Stem Cells.

    Science.gov (United States)

    Johari, Behrooz; Ebrahimi-Rad, Mina; Maghsood, Faezeh; Lotfinia, Majid; Saltanatpouri, Zohreh; Teimoori-Toolabi, Ladan; Sharifzadeh, Zahra; Karimipoor, Morteza; Kadivar, Mehdi

    2017-01-01

    Myc (c-Myc) alone activates the embryonic stem cell-like transcriptional module in both normal and transformed cells. Its dysregulation might lead to increased cancer stem cells (CSCs) population in some tumor cells. In order to investigate the potential of Myc decoy oligodeoxynucleotides for differentiation therapy, mouse embryonic stem cells (mESCs) were used in this study as a model of CSCs. To our best of knowledge this is the first report outlining the application of Myc decoy in transcription factor decoy "TFD" strategy for inducing differentiation in mESCs. A 20-mer double-stranded Myc transcription factor decoy and scrambled oligodeoxynucleotides (ODNs) were designed, analyzed by electrophoretic mobility shift (EMSA) assay and transfected into the mESCs under 2 inhibitors (2i) condition. Further investigations were carried out using fluorescence and confocal microscopy, cell proliferation and apoptosis analysis, alkaline phosphatase and embryoid body formation assay, real-time PCR and western blotting. EMSA data showed that Myc decoy ODNs bound specifically to c-Myc protein. They were found to be localized in both cytoplasm and nucleus of mESCs. Our results revealed the potential capability of Myc decoy ODNs to decrease cell viability by (16.1±2%), to increase the number of cells arrested in G0/G1 phases and apoptosis by (14.2±3.1%) and (12.1±3.2%), respectively regarding the controls. Myc decoy could also modulate differentiation in mESCs despite the presence of 2i/LIF in our medium the presence of 2i/LIF in our medium. The optimized Myc decoy ODNs approach might be considered as a promising alternative strategy for differentiation therapy investigations. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  6. The first report of the vanC1 gene in Enterococcus faecium isolated from a human clinical specimen

    Directory of Open Access Journals (Sweden)

    Mingyue Sun

    2014-09-01

    Full Text Available The vanC1 gene, which is chromosomally located, confers resistance to vancomycin and serves as a species marker for Enterococcus gallinarum. Enterococcus faecium TJ4031 was isolated from a blood culture and harbours the vanC1gene. Polymerase chain reaction (PCR assays were performed to detect vanXYc and vanTc genes. Only the vanXYc gene was found in the E. faecium TJ4031 isolate. The minimum inhibitory concentrations of vancomycin and teicoplanin were 2 µg/mL and 1 µg/mL, respectively. Real-time reverse transcription-PCR results revealed that the vanC1and vanXYc genes were not expressed. Pulsed-field gel electrophoresis and southern hybridisation results showed that the vanC1 gene was encoded in the chromosome. E. faecalis isolated from animals has been reported to harbour vanC1gene. However, this study is the first to report the presence of the vanC1gene in E. faecium of human origin. Additionally, our research showed the vanC1gene cannot serve as a species-specific gene of E. gallinarum and that it is able to be transferred between bacteria. Although the resistance marker is not expressed in the strain, our results showed that E. faecium could acquire the vanC1gene from different species.

  7. Human tissue factor: cDNA sequence and chromosome localization of the gene

    International Nuclear Information System (INIS)

    Scarpati, E.M.; Wen, D.; Broze, G.J. Jr.; Miletich, J.P.; Flandermeyer, R.R.; Siegel, N.R.; Sadler, J.E.

    1987-01-01

    A human placenta cDNA library in λgt11 was screened for the expression of tissue factor antigens with rabbit polyclonal anti-human tissue factor immunoglobulin G. Among 4 million recombinant clones screened, one positive, λHTF8, expressed a protein that shared epitopes with authentic human brain tissue factor. The 1.1-kilobase cDNA insert of λHTF8 encoded a peptide that contained the amino-terminal protein sequence of human brain tissue factor. Northern blotting identified a major mRNA species of 2.2 kilobases and a minor species of ∼ 3.2 kilobases in poly(A) + RNA of placenta. Only 2.2-kilobase mRNA was detected in human brain and in the human monocytic U937 cell line. In U937 cells, the quantity of tissue factor mRNA was increased several fold by exposure of the cells to phorbol 12-myristate 13-acetate. Additional cDNA clones were selected by hybridization with the cDNA insert of λHTF8. These overlapping isolates span 2177 base pairs of the tissue factor cDNA sequence that includes a 5'-noncoding region of 75 base pairs, an open reading frame of 885 base pairs, a stop codon, a 3'-noncoding region of 1141 base pairs, and a poly(a) tail. The open reading frame encodes a 33-kilodalton protein of 295 amino acids. The predicted sequence includes a signal peptide of 32 or 34 amino acids, a probable extracellular factor VII binding domain of 217 or 219 amino acids, a transmembrane segment of 23 acids, and a cytoplasmic tail of 21 amino acids. There are three potential glycosylation sites with the sequence Asn-X-Thr/Ser. The 3'-noncoding region contains an inverted Alu family repetitive sequence. The tissue factor gene was localized to chromosome 1 by hybridization of the cDNA insert of λHTF8 to flow-sorted human chromosomes

  8. In vivo efficacy of the Bcl-2 antagonist ABT-737 against aggressive Myc-driven lymphomas

    OpenAIRE

    Mason, Kylie D.; Vandenberg, Cassandra J.; Scott, Clare L.; Wei, Andrew H.; Cory, Suzanne; Huang, David C. S.; Roberts, Andrew W.

    2008-01-01

    Deregulated Myc expression drives many human cancers, including Burkitt's lymphoma and a highly aggressive subset of diffuse large cell lymphomas. Myc-driven tumors often display resistance to chemotherapeutics because of acquisition of mutations that impair the apoptosis pathway regulated by the Bcl-2 protein family. Given the need to identify new therapies for such lymphomas, we have evaluated the efficacy of ABT-737, a small molecule that mimics the action of the BH3-only proteins, natural...

  9. CDK-mediated activation of the SCFFBXO28 ubiquitin ligase promotes MYC-driven transcription and tumourigenesis and predicts poor survival in breast cancer

    Science.gov (United States)

    Cepeda, Diana; Ng, Hwee-Fang; Sharifi, Hamid Reza; Mahmoudi, Salah; Cerrato, Vanessa Soto; Fredlund, Erik; Magnusson, Kristina; Nilsson, Helén; Malyukova, Alena; Rantala, Juha; Klevebring, Daniel; Viñals, Francesc; Bhaskaran, Nimesh; Zakaria, Siti Mariam; Rahmanto, Aldwin Suryo; Grotegut, Stefan; Nielsen, Michael Lund; Szigyarto, Cristina Al-Khalili; Sun, Dahui; Lerner, Mikael; Navani, Sanjay; Widschwendter, Martin; Uhlén, Mathias; Jirström, Karin; Pontén, Fredrik; Wohlschlegel, James; Grandér, Dan; Spruck, Charles; Larsson, Lars-Gunnar; Sangfelt, Olle

    2013-01-01

    SCF (Skp1/Cul1/F-box) ubiquitin ligases act as master regulators of cellular homeostasis by targeting key proteins for ubiquitylation. Here, we identified a hitherto uncharacterized F-box protein, FBXO28 that controls MYC-dependent transcription by non-proteolytic ubiquitylation. SCFFBXO28 activity and stability are regulated during the cell cycle by CDK1/2-mediated phosphorylation of FBXO28, which is required for its efficient ubiquitylation of MYC and downsteam enhancement of the MYC pathway. Depletion of FBXO28 or overexpression of an F-box mutant unable to support MYC ubiquitylation results in an impairment of MYC-driven transcription, transformation and tumourigenesis. Finally, in human breast cancer, high FBXO28 expression and phosphorylation are strong and independent predictors of poor outcome. In conclusion, our data suggest that SCFFBXO28 plays an important role in transmitting CDK activity to MYC function during the cell cycle, emphasizing the CDK-FBXO28-MYC axis as a potential molecular drug target in MYC-driven cancers, including breast cancer. PMID:23776131

  10. Prognostic significance of MYC, BCL2, and BCL6 rearrangements in patients with diffuse large B-cell lymphoma treated with cyclophosphamide, doxorubicin, vincristine, and prednisone plus rituximab.

    Science.gov (United States)

    Akyurek, Nalan; Uner, Aysegul; Benekli, Mustafa; Barista, Ibrahim

    2012-09-01

    Diffuse large B-cell lymphomas (DLBCLs) are a biologically heterogeneous group in which various gene alterations have been reported. The aim of this study was to investigate the frequency and prognostic impact of BCL2, BCL6, and MYC rearrangements in cyclophosphamide, doxorubicin, vincristine, and prednisone plus rituximab (R-CHOP)-treated DLBCL cases. Tissue microarrays were constructed from 239 cases of DLBCL, and the expressions of CD10, BCL6, MUM1/IRF4, and BCL2 were evaluated by immunohistochemistry. MYC, BCL2, and BCL6 rearrangements were investigated by interphase fluorescence in situ hybridization on tissue microarrays. Survival analysis was constructed from 145 R-CHOP-treated patients. MYC, BCL2, and BCL6 rearrangements were detected in 14 (6%), 36 (15%), and 69 (29%) of 239 DLBCL patients. Double or triple rearrangements were detected in 7 (3%) of 239 DLBCL cases. Of these, 4 had BCL2 and MYC, 2 had BCL6 and MYC, and 1 had BCL2, BCL6, and MYC rearrangements. The prognosis of these cases was extremely poor, with a median survival of 9 months. MYC rearrangement was associated with significantly worse overall survival (P = .01), especially for the cases with GC phenotype (P = .009). BCL6 rearrangement also predicted significantly shorter overall survival (P = .04), especially for the non-GC phenotype (P = .03). BCL2 rearrangement had no prognostic impact on outcome. International Prognostic Index (P = .004) and MYC rearrangement (P = .009) were independent poor prognostic factors. Analysis of MYC gene rearrangement along with BCL2 and BCL6 is critical in identifying high-risk patients with poor prognosis. Copyright © 2011 American Cancer Society.

  11. Modulation of expression of genes encoding nuclear proteins following exposure to JANUS neutrons or γ-rays

    International Nuclear Information System (INIS)

    Woloschak, G.E.; Chang-Liu, Chin-Mei

    1994-01-01

    Previous work has shown that exposure of cells to ionizing radiations causes modulation of a variety of genes, including those encoding c-fos, interleukin-1, tumor necrosis factor, cytoskeletal elements, and many more. The experiments reported herein were designed to examine the effects of either JANUS neutron or γ-ray exposure on expression of genes encoding nucleus-associated proteins (H4-histone, c-jun, c-myc, Rb, and p53). Cycling Syrian hamster embryo cells were irradiated with varying doses and dose rates of either JANUS fission-spectrum neutrons or γ-rays; after incubation of the cell cultures for 1 h following radiation exposure, mRNA was harvested and analyzed by Northern blot. Results revealed induction of transcripts for c-jun, H4-histone, and Rb following γ-ray but not following neutron exposure. Interestingly, expression of c-myc was repressed following γ-ray but not following neutron exposure. Radiations at different doses and dose rates were compared for each of the genes studied

  12. cMyc/miR-125b-5p signalling determines sensitivity to bortezomib in preclinical model of cutaneous T-cell lymphomas

    DEFF Research Database (Denmark)

    Manfè, Valentina; Biskup, Edyta; Willumsgaard, Ayalah

    2013-01-01

    Successful/effective cancer therapy in low grade lymphoma is often hampered by cell resistance to anti-neoplastic agents. The crucial mechanisms responsible for this phenomenon are poorly understood. Overcoming resistance of tumor cells to anticancer agents, such as proteasome inhibitors, could...... improve their clinical efficacy. Using cutaneous T-cell lymphoma (CTCL) as a model of the chemotherapy-resistant peripheral lymphoid malignancy, we demonstrated that resistance to proteasome inhibition involved a signaling between the oncogene cMyc and miR-125b-5p. Bortezomib repressed c...

  13. Activation of pluripotency genes in human fibroblast cells by a novel mRNA based approach.

    Directory of Open Access Journals (Sweden)

    Jordan R Plews

    2010-12-01

    Full Text Available Several methods have been used to induce somatic cells to re-enter the pluripotent state. Viral transduction of reprogramming genes yields higher efficiency but involves random insertions of viral sequences into the human genome. Although induced pluripotent stem (iPS cells can be obtained with the removable PiggyBac transposon system or an episomal system, both approaches still use DNA constructs so that resulting cell lines need to be thoroughly analyzed to confirm they are free of harmful genetic modification. Thus a method to change cell fate without using DNA will be very useful in regenerative medicine.In this study, we synthesized mRNAs encoding OCT4, SOX2, cMYC, KLF4 and SV40 large T (LT and electroporated them into human fibroblast cells. Upon transfection, fibroblasts expressed these factors at levels comparable to, or higher than those in human embryonic stem (ES cells. Ectopically expressed OCT4 localized to the cell nucleus within 4 hours after mRNA introduction. Transfecting fibroblasts with a mixture of mRNAs encoding all five factors significantly increased the expression of endogenous OCT4, NANOG, DNMT3β, REX1 and SALL4. When such transfected fibroblasts were also exposed to several small molecules (valproic acid, BIX01294 and 5'-aza-2'-deoxycytidine and cultured in human embryonic stem cell (ES medium they formed small aggregates positive for alkaline phosphatase activity and OCT4 protein within 30 days.Our results demonstrate that mRNA transfection can be a useful approach to precisely control the protein expression level and short-term expression of reprogramming factors is sufficient to activate pluripotency genes in differentiated cells.

  14. Identification and characterization of human GUKH2 gene in silico.

    Science.gov (United States)

    Katoh, Masuko; Katoh, Masaru

    2004-04-01

    Drosophila Guanylate-kinase holder (Gukh) is an adaptor molecule bridging Discs large (Dlg) and Scribble (Scrib), which are implicated in the establishment and maintenance of epithelial polarity. Here, we searched for human homologs of Drosophila gukh by using bioinformatics, and identified GUKH1 and GUKH2 genes. GUKH1 was identical to Nance-Horan syndrome (NHS) gene, while GUKH2 was a novel gene. FLJ35425 (AK092744.1), DKFZp686P1949 (BX647246.1) and KIAA1357 (AB037778.1) cDNAs were derived from human GUKH2 gene. Nucleotide sequence of GUKH2 cDNA was determined by assembling 5'-part of FLJ35425 cDNA and entire region of DKFZp686P1949 cDNA. Human GUKH2 gene consists of 8 exons. Exon 5 (132 bp) of GUKH2 gene was spliced out in GUKH2 cDNA due to alternative splicing. GUKH2-REPS1 locus at human chromosome 6q24.1 and GUKH1-REPS2 locus at human chromosome Xp22.22-p22.13 are paralogous regions within the human genome. Mouse Gukh2 and zebrafish gukh2 genes were also identified. N-terminal part of human GUKH2, mouse Gukh2 and zebrafish gukh2 proteins were completely divergent from human GUKH1 protein. Human GUKH2 and GUKH1, consisting of eight GUKH homology (GKH1-GKH8) domains and Proline-rich domain, showed 28.5% total-amino-acid identity. GKH1, GKH4, GKH5, GKH7 and GKH8 domains were conserved among human GUKH1, human GUKH2 and Drosophila Gukh. Because human homologs of Drosophila dlg (DLG1-DLG7) as well as human homologs of Drosophila scrib (SCRIB, ERBB2IP and Densin-180) are cancer-associated genes, human homologs of Drosophila gukh (GUKH1 and GUKH2) are predicted cancer-associated genes.

  15. DNA methylation-dependent regulation of TrkA, TrkB, and TrkC genes in human hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Wook [Laboratory of Molecular Disease and Cell Regulation, Lee Gil Ya Cancer and Diabetes Institute, Gachon University of Medicine and Science, Incheon (Korea, Republic of); Lee, Jong-Joo [Department of Environmental Medical Biology, Institute of Tropical Medicine, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Kim, Min Soo [Laboratory of Molecular Disease and Cell Regulation, Lee Gil Ya Cancer and Diabetes Institute, Gachon University of Medicine and Science, Incheon (Korea, Republic of); Son, Byung Ho [Department of Surgery, Kangbuk Samsung Hospital, Sungkyunkwan University, School of Medicine, 108 Pyung-dong, Jongro-gu, Seoul 110-746 (Korea, Republic of); Cho, Yong Kyun, E-mail: choyk2004@hanmail.net [Division of Gastroenterology, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University, School of Medicine, 108 Pyung-dong, Jongro-gu, Seoul 110-746 (Korea, Republic of); Kim, Hyoung-Pyo, E-mail: kimhp@yuhs.ac [Department of Environmental Medical Biology, Institute of Tropical Medicine, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul 120-752 (Korea, Republic of)

    2011-03-04

    Research highlights: {yields} Expression of TrkA, TrkB, and TrkC is significantly elevated in human hepatocellular carcinoma. {yields} Downregulation of Trks is correlated with their promoter hypermethylation. {yields} Inhibiting DNA methylation restored expression of Trks in normal liver cell lines. {yields} Trks promote the proliferation of hepatocellular carcinoma. {yields} Trks induce expression of the metastatic regulator, Twist. -- Abstract: The tropomyosin-related kinase (Trk) family of neurotrophin receptors, TrkA, TrkB and TrkC, has been implicated in the growth and survival of human cancers. Here we report that Trks are frequently overexpressed in hepatocellular carcinoma (HCC) from patients and human liver cancer cell lines. To unravel the underlying molecular mechanism(s) for this phenomenon, DNA methylation patterns of CpG islands in TrkA, TrkB, and TrkC genes were examined in normal and cancer cell lines derived from liver. A good correlation was observed between promoter hypermethylation and lower expression of TrkA, TrkB, and TrkC genes, which was supported by the data that inhibiting DNA methylation with 5-azacytidine restored expression of those genes in normal liver cell lines. Furthermore, Trks promoted the proliferation of HepG2 and induced expression of the metastatic regulator, Twist. These results suggest that Trks may contribute to growth and metastasis of liver cancer.

  16. DNA methylation-dependent regulation of TrkA, TrkB, and TrkC genes in human hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Jin, Wook; Lee, Jong-Joo; Kim, Min Soo; Son, Byung Ho; Cho, Yong Kyun; Kim, Hyoung-Pyo

    2011-01-01

    Research highlights: → Expression of TrkA, TrkB, and TrkC is significantly elevated in human hepatocellular carcinoma. → Downregulation of Trks is correlated with their promoter hypermethylation. → Inhibiting DNA methylation restored expression of Trks in normal liver cell lines. → Trks promote the proliferation of hepatocellular carcinoma. → Trks induce expression of the metastatic regulator, Twist. -- Abstract: The tropomyosin-related kinase (Trk) family of neurotrophin receptors, TrkA, TrkB and TrkC, has been implicated in the growth and survival of human cancers. Here we report that Trks are frequently overexpressed in hepatocellular carcinoma (HCC) from patients and human liver cancer cell lines. To unravel the underlying molecular mechanism(s) for this phenomenon, DNA methylation patterns of CpG islands in TrkA, TrkB, and TrkC genes were examined in normal and cancer cell lines derived from liver. A good correlation was observed between promoter hypermethylation and lower expression of TrkA, TrkB, and TrkC genes, which was supported by the data that inhibiting DNA methylation with 5-azacytidine restored expression of those genes in normal liver cell lines. Furthermore, Trks promoted the proliferation of HepG2 and induced expression of the metastatic regulator, Twist. These results suggest that Trks may contribute to growth and metastasis of liver cancer.

  17. CDK-mediated activation of the SCF(FBXO) (28) ubiquitin ligase promotes MYC-driven transcription and tumourigenesis and predicts poor survival in breast cancer

    DEFF Research Database (Denmark)

    Cepeda, Diana; Ng, Hwee-Fang; Sharifi, Hamid Reza

    2013-01-01

    SCF (Skp1/Cul1/F-box) ubiquitin ligases act as master regulators of cellular homeostasis by targeting key proteins for ubiquitylation. Here, we identified a hitherto uncharacterized F-box protein, FBXO28 that controls MYC-dependent transcription by non-proteolytic ubiquitylation. SCF(FBXO28...... results in an impairment of MYC-driven transcription, transformation and tumourigenesis. Finally, in human breast cancer, high FBXO28 expression and phosphorylation are strong and independent predictors of poor outcome. In conclusion, our data suggest that SCF(FBXO28) plays an important role...... in transmitting CDK activity to MYC function during the cell cycle, emphasizing the CDK-FBXO28-MYC axis as a potential molecular drug target in MYC-driven cancers, including breast cancer....

  18. The Functional Human C-Terminome.

    Directory of Open Access Journals (Sweden)

    Surbhi Sharma

    Full Text Available All translated proteins end with a carboxylic acid commonly called the C-terminus. Many short functional sequences (minimotifs are located on or immediately proximal to the C-terminus. However, information about the function of protein C-termini has not been consolidated into a single source. Here, we built a new "C-terminome" database and web system focused on human proteins. Approximately 3,600 C-termini in the human proteome have a minimotif with an established molecular function. To help evaluate the function of the remaining C-termini in the human proteome, we inferred minimotifs identified by experimentation in rodent cells, predicted minimotifs based upon consensus sequence matches, and predicted novel highly repetitive sequences in C-termini. Predictions can be ranked by enrichment scores or Gene Evolutionary Rate Profiling (GERP scores, a measurement of evolutionary constraint. By searching for new anchored sequences on the last 10 amino acids of proteins in the human proteome with lengths between 3-10 residues and up to 5 degenerate positions in the consensus sequences, we have identified new consensus sequences that predict instances in the majority of human genes. All of this information is consolidated into a database that can be accessed through a C-terminome web system with search and browse functions for minimotifs and human proteins. A known consensus sequence-based predicted function is assigned to nearly half the proteins in the human proteome. Weblink: http://cterminome.bio-toolkit.com.

  19. The Functional Human C-Terminome

    Science.gov (United States)

    Hedden, Michael; Lyon, Kenneth F.; Brooks, Steven B.; David, Roxanne P.; Limtong, Justin; Newsome, Jacklyn M.; Novakovic, Nemanja; Rajasekaran, Sanguthevar; Thapar, Vishal; Williams, Sean R.; Schiller, Martin R.

    2016-01-01

    All translated proteins end with a carboxylic acid commonly called the C-terminus. Many short functional sequences (minimotifs) are located on or immediately proximal to the C-terminus. However, information about the function of protein C-termini has not been consolidated into a single source. Here, we built a new “C-terminome” database and web system focused on human proteins. Approximately 3,600 C-termini in the human proteome have a minimotif with an established molecular function. To help evaluate the function of the remaining C-termini in the human proteome, we inferred minimotifs identified by experimentation in rodent cells, predicted minimotifs based upon consensus sequence matches, and predicted novel highly repetitive sequences in C-termini. Predictions can be ranked by enrichment scores or Gene Evolutionary Rate Profiling (GERP) scores, a measurement of evolutionary constraint. By searching for new anchored sequences on the last 10 amino acids of proteins in the human proteome with lengths between 3–10 residues and up to 5 degenerate positions in the consensus sequences, we have identified new consensus sequences that predict instances in the majority of human genes. All of this information is consolidated into a database that can be accessed through a C-terminome web system with search and browse functions for minimotifs and human proteins. A known consensus sequence-based predicted function is assigned to nearly half the proteins in the human proteome. Weblink: http://cterminome.bio-toolkit.com. PMID:27050421

  20. Secretory TAT-peptide-mediated protein transduction of LIF receptor α-chain distal cytoplasmic motifs into human myeloid HL-60 cells

    Directory of Open Access Journals (Sweden)

    Q. Sun

    2012-10-01

    Full Text Available The distal cytoplasmic motifs of leukemia inhibitory factor receptor α-chain (LIFRα-CT3 can independently induce intracellular myeloid differentiation in acute myeloid leukemia (AML cells by gene transfection; however, there are significant limitations in the potential clinical use of these motifs due to liposome-derived genetic modifications. To produce a potentially therapeutic LIFRα-CT3 with cell-permeable activity, we constructed a eukaryotic expression pcDNA3.0-TAT-CT3-cMyc plasmid with a signal peptide (ss inserted into the N-terminal that codes for an ss-TAT-CT3-cMyc fusion protein. The stable transfection of Chinese hamster ovary (CHO cells via this vector and subsequent selection by Geneticin resulted in cell lines that express and secrete TAT-CT3-cMyc. The spent medium of pcDNA3.0-TAT-CT3-cMyc-transfected CHO cells could be purified using a cMyc-epitope-tag agarose affinity chromatography column and could be detected via SDS-PAGE, with antibodies against cMyc-tag. The direct administration of TAT-CT3-cMyc to HL-60 cell culture media caused the enrichment of CT3-cMyc in the cytoplasm and nucleus within 30 min and led to a significant reduction of viable cells (P < 0.05 8 h after exposure. The advantages of using this mammalian expression system include the ease of generating TAT fusion proteins that are adequately transcripted and the potential for a sustained production of such proteins in vitro for future AML therapy.

  1. Secretory TAT-peptide-mediated protein transduction of LIF receptor α-chain distal cytoplasmic motifs into human myeloid HL-60 cells

    International Nuclear Information System (INIS)

    Sun, Q.; Xiong, J.; Lu, J.; Xu, S.; Li, Y.; Zhong, X.P.; Gao, G.K.; Liu, H.Q.

    2012-01-01

    The distal cytoplasmic motifs of leukemia inhibitory factor receptor α-chain (LIFRα-CT3) can independently induce intracellular myeloid differentiation in acute myeloid leukemia (AML) cells by gene transfection; however, there are significant limitations in the potential clinical use of these motifs due to liposome-derived genetic modifications. To produce a potentially therapeutic LIFRα-CT3 with cell-permeable activity, we constructed a eukaryotic expression pcDNA3.0-TAT-CT3-cMyc plasmid with a signal peptide (ss) inserted into the N-terminal that codes for an ss-TAT-CT3-cMyc fusion protein. The stable transfection of Chinese hamster ovary (CHO) cells via this vector and subsequent selection by Geneticin resulted in cell lines that express and secrete TAT-CT3-cMyc. The spent medium of pcDNA3.0-TAT-CT3-cMyc-transfected CHO cells could be purified using a cMyc-epitope-tag agarose affinity chromatography column and could be detected via SDS-PAGE, with antibodies against cMyc-tag. The direct administration of TAT-CT3-cMyc to HL-60 cell culture media caused the enrichment of CT3-cMyc in the cytoplasm and nucleus within 30 min and led to a significant reduction of viable cells (P < 0.05) 8 h after exposure. The advantages of using this mammalian expression system include the ease of generating TAT fusion proteins that are adequately transcripted and the potential for a sustained production of such proteins in vitro for future AML therapy

  2. Secretory TAT-peptide-mediated protein transduction of LIF receptor α-chain distal cytoplasmic motifs into human myeloid HL-60 cells

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Q. [Department of Hyperbaric Medicine, No. 401 Hospital of PLA, Qingdao (China); Department of Histology and Embryology, Faculty of Basic Medical Sciences, Second Military Medical University, Shanghai (China); Xiong, J. [Department of Histology and Embryology, Faculty of Basic Medical Sciences, Second Military Medical University, Shanghai (China); Lu, J. [Office of Medical Education, Training Department, Second Military Medical University, Shanghai (China); Xu, S. [Department of Histology and Embryology, Faculty of Basic Medical Sciences, Second Military Medical University, Shanghai (China); Li, Y. [State Food and Drug Administration of China,Huangdao Branch, Qingdao (China); Zhong, X.P.; Gao, G.K. [Department of Hyperbaric Medicine, No. 401 Hospital of PLA, Qingdao (China); Liu, H.Q. [2Department of Histology and Embryology, Faculty of Basic Medical Sciences, Second Military Medical University, Shanghai (China)

    2012-06-22

    The distal cytoplasmic motifs of leukemia inhibitory factor receptor α-chain (LIFRα-CT3) can independently induce intracellular myeloid differentiation in acute myeloid leukemia (AML) cells by gene transfection; however, there are significant limitations in the potential clinical use of these motifs due to liposome-derived genetic modifications. To produce a potentially therapeutic LIFRα-CT3 with cell-permeable activity, we constructed a eukaryotic expression pcDNA3.0-TAT-CT3-cMyc plasmid with a signal peptide (ss) inserted into the N-terminal that codes for an ss-TAT-CT3-cMyc fusion protein. The stable transfection of Chinese hamster ovary (CHO) cells via this vector and subsequent selection by Geneticin resulted in cell lines that express and secrete TAT-CT3-cMyc. The spent medium of pcDNA3.0-TAT-CT3-cMyc-transfected CHO cells could be purified using a cMyc-epitope-tag agarose affinity chromatography column and could be detected via SDS-PAGE, with antibodies against cMyc-tag. The direct administration of TAT-CT3-cMyc to HL-60 cell culture media caused the enrichment of CT3-cMyc in the cytoplasm and nucleus within 30 min and led to a significant reduction of viable cells (P < 0.05) 8 h after exposure. The advantages of using this mammalian expression system include the ease of generating TAT fusion proteins that are adequately transcripted and the potential for a sustained production of such proteins in vitro for future AML therapy.

  3. Cloning and sequencing of cDNA encoding human DNA topoisomerase II and localization of the gene to chromosome region 17q21-22

    International Nuclear Information System (INIS)

    Tsai-Pflugfelder, M.; Liu, L.F.; Liu, A.A.; Tewey, K.M.; Whang-Peng, J.; Knutsen, T.; Huebner, K.; Croce, C.M.; Wang, J.C.

    1988-01-01

    Two overlapping cDNA clones encoding human DNA topoisomerase II were identified by two independent methods. In one, a human cDNA library in phage λ was screened by hybridization with a mixed oligonucleotide probe encoding a stretch of seven amino acids found in yeast and Drosophila DNA topoisomerase II; in the other, a different human cDNA library in a λgt11 expression vector was screened for the expression of antigenic determinants that are recognized by rabbit antibodies specific to human DNA topoisomerase II. The entire coding sequences of the human DNA topoisomerase II gene were determined from these and several additional clones, identified through the use of the cloned human TOP2 gene sequences as probes. Hybridization between the cloned sequences and mRNA and genomic DNA indicates that the human enzyme is encoded by a single-copy gene. The location of the gene was mapped to chromosome 17q21-22 by in situ hybridization of a cloned fragment to metaphase chromosomes and by hybridization analysis with a panel of mouse-human hybrid cell lines, each retaining a subset of human chromosomes

  4. Characterization of human septic sera induced gene expression modulation in human myocytes

    Science.gov (United States)

    Hussein, Shaimaa; Michael, Paul; Brabant, Danielle; Omri, Abdelwahab; Narain, Ravin; Passi, Kalpdrum; Ramana, Chilakamarti V.; Parrillo, Joseph E.; Kumar, Anand; Parissenti, Amadeo; Kumar, Aseem

    2009-01-01

    To gain a better understanding of the gene expression changes that occurs during sepsis, we have performed a cDNA microarray study utilizing a tissue culture model that mimics human sepsis. This study utilized an in vitro model of cultured human fetal cardiac myocytes treated with 10% sera from septic patients or 10% sera from healthy volunteers. A 1700 cDNA expression microarray was used to compare the transcription profile from human cardiac myocytes treated with septic sera vs normal sera. Septic sera treatment of myocytes resulted in the down-regulation of 178 genes and the up-regulation of 4 genes. Our data indicate that septic sera induced cell cycle, metabolic, transcription factor and apoptotic gene expression changes in human myocytes. Identification and characterization of gene expression changes that occur during sepsis may lead to the development of novel therapeutics and diagnostics. PMID:19684886

  5. PAF-Myc-Controlled Cell Stemness Is Required for Intestinal Regeneration and Tumorigenesis.

    Science.gov (United States)

    Kim, Moon Jong; Xia, Bo; Suh, Han Na; Lee, Sung Ho; Jun, Sohee; Lien, Esther M; Zhang, Jie; Chen, Kaifu; Park, Jae-Il

    2018-03-12

    The underlying mechanisms of how self-renewing cells are controlled in regenerating tissues and cancer remain ambiguous. PCNA-associated factor (PAF) modulates DNA repair via PCNA. Also, PAF hyperactivates Wnt/β-catenin signaling independently of PCNA interaction. We found that PAF is expressed in intestinal stem and progenitor cells (ISCs and IPCs) and markedly upregulated during intestinal regeneration and tumorigenesis. Whereas PAF is dispensable for intestinal homeostasis, upon radiation injury, genetic ablation of PAF impairs intestinal regeneration along with the severe loss of ISCs and Myc expression. Mechanistically, PAF conditionally occupies and transactivates the c-Myc promoter, which induces the expansion of ISCs/IPCs during intestinal regeneration. In mouse models, PAF knockout inhibits Apc inactivation-driven intestinal tumorigenesis with reduced tumor cell stemness and suppressed Wnt/β-catenin signaling activity, supported by transcriptome profiling. Collectively, our results unveil that the PAF-Myc signaling axis is indispensable for intestinal regeneration and tumorigenesis by positively regulating self-renewing cells. Copyright © 2018 Elsevier Inc. All rights reserved.

  6. Radioactive cDNA microarray (II): Gene expression profiling of antidepressant treatment by human cDNA microarray

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ji Hye; Kang, Rhee Hun; Ham, Byung Joo; Lee, Min Su; Shin, Kyung Ho; Choe, Jae Gol; Kim, Meyoung Kon [College of Medicine, Univ. of Korea, Seoul (Korea, Republic of)

    2003-07-01

    Major depressive disorder is a prevalent psychiatric disorder in primary care, associated with impaired patient functioning and well-being. Fluoxetine is a selective serotonin-reuptake inhibitors (SSRIs) and is a commonly prescribed antidepressant compound. Its action is primarily attributed to selective inhibition of the reuptake of serotonin (5-hydroxytryptamine) in the central nervous system. Objectives ; the aims of this study were two-fold: (1) to determine the usefulness for investigation of the transcription profiles in depression patients, and (2) to assess the differences in gene expression profiles between positive response group and negative response groups by fluoxetine treatment. This study included 53 patients with major depression (26 in positive response group with antidepressant treatment, 27 in negative response group with antidepressant treatment), and 53 healthy controls. To examine the difference of gene expression profile in depression patients, radioactive complementary DNA microarrays were used to evaluate changes in the expression of 1,152 genes in total. Using 33p-labeled probes, this method provided highly sensitive gene expression profiles including brain receptors, drug metabolism, and cellular signaling. Gene transcription profiles were classified into several categories in accordance with the antidepressant gene-regulation. The gene profiles were significantly up-(22 genes) and down-(16 genes) regulated in the positive response group when compared to the control group. Also, in the negative response group, 35 genes were up-regulated and 8 genes were down-regulated when compared to the control group. Consequently, we demonstrated that radioactive human cDNA microarray is highly likely to be an efficient technology for evaluating the gene regulation of antidepressants, such as selective serotonin-reuptake inhibitors (SSRIs), by using high-throughput biotechnology.

  7. Radioactive cDNA microarray (II): Gene expression profiling of antidepressant treatment by human cDNA microarray

    International Nuclear Information System (INIS)

    Lee, Ji Hye; Kang, Rhee Hun; Ham, Byung Joo; Lee, Min Su; Shin, Kyung Ho; Choe, Jae Gol; Kim, Meyoung Kon

    2003-01-01

    Major depressive disorder is a prevalent psychiatric disorder in primary care, associated with impaired patient functioning and well-being. Fluoxetine is a selective serotonin-reuptake inhibitors (SSRIs) and is a commonly prescribed antidepressant compound. Its action is primarily attributed to selective inhibition of the reuptake of serotonin (5-hydroxytryptamine) in the central nervous system. Objectives ; the aims of this study were two-fold: (1) to determine the usefulness for investigation of the transcription profiles in depression patients, and (2) to assess the differences in gene expression profiles between positive response group and negative response groups by fluoxetine treatment. This study included 53 patients with major depression (26 in positive response group with antidepressant treatment, 27 in negative response group with antidepressant treatment), and 53 healthy controls. To examine the difference of gene expression profile in depression patients, radioactive complementary DNA microarrays were used to evaluate changes in the expression of 1,152 genes in total. Using 33p-labeled probes, this method provided highly sensitive gene expression profiles including brain receptors, drug metabolism, and cellular signaling. Gene transcription profiles were classified into several categories in accordance with the antidepressant gene-regulation. The gene profiles were significantly up-(22 genes) and down-(16 genes) regulated in the positive response group when compared to the control group. Also, in the negative response group, 35 genes were up-regulated and 8 genes were down-regulated when compared to the control group. Consequently, we demonstrated that radioactive human cDNA microarray is highly likely to be an efficient technology for evaluating the gene regulation of antidepressants, such as selective serotonin-reuptake inhibitors (SSRIs), by using high-throughput biotechnology

  8. Human proton/oligopeptide transporter (POT) genes

    DEFF Research Database (Denmark)

    Botka, C. W.; Wittig, T. W.; Graul, R. C.

    2000-01-01

    The proton-dependent oligopeptide transporters (POT) gene family currently consists of approximately 70 cloned cDNAs derived from diverse organisms. In mammals, two genes encoding peptide transporters, PepT1 and PepT2 have been cloned in several species including humans, in addition to a rat...... histidine/peptide transporter (rPHT1). Because the Candida elegans genome contains five putative POT genes, we searched the available protein and nucleic acid databases for additional mammalian/human POT genes, using iterative BLAST runs and the human expressed sequence tags (EST) database. The apparent...... and introns of the likely human orthologue (termed hPHT2). Northern analyses with EST clones indicated that hPHT1 is primarily expressed in skeletal muscle and spleen, whereas hPHT2 is found in spleen, placenta, lung, leukocytes, and heart. These results suggest considerable complexity of the human POT gene...

  9. Distinct Histopathologic and Molecular Alterations in Inflammatory Bowel Disease-Associated Intestinal Adenocarcinoma: c-MYC Amplification is Common and Associated with Mucinous/Signet Ring Cell Differentiation.

    Science.gov (United States)

    Hartman, Douglas J; Binion, David G; Regueiro, Miguel D; Miller, Caitlyn; Herbst, Cameron; Pai, Reetesh K

    2018-05-17

    Chronic idiopathic inflammatory bowel disease (IBD) is a significant risk factor for the development of intestinal adenocarcinoma. The underlying molecular alterations in IBD-associated intestinal adenocarcinoma remain largely unknown. We compared the clinicopathologic and molecular features of 35 patients with 47 IBD-associated intestinal adenocarcinomas with a consecutive series of 451 patients with sporadic colorectal carcinoma identified at our institution and published data on sporadic colorectal carcinoma. c-MYC amplification was the most frequent molecular alteration identified in 33% of IBD-associated intestinal adenocarcinoma that is a significantly higher frequency than in sporadic colorectal carcinoma (8%) (P = 0.0001). Compared to sporadic colorectal carcinoma, IBD-associated intestinal adenocarcinomas more frequently demonstrated mucinous differentiation (60% vs 25%, P < 0.001) and signet ring cell differentiation (28% vs 4%, P < 0.001). Mucinous and signet ring cell differentiation were significantly associated with the presence of c-MYC amplification (both with P < 0.05). HER2 positivity (11%), KRAS exon 2 or 3 mutation (10%), and IDH1 mutation (7%) were less commonly observed in IBD-associated intestinal adenocarcinoma. There was an association between poor survival and HER2 status with 3 of 4 patients having HER2-positive adenocarcinoma dead of disease at last clinical follow-up; however, no statistically significant survival effect was identified for any of the molecular alterations identified. We demonstrate that IBD-associated intestinal adenocarcinomas have a high frequency of c-MYC amplification that is associated with mucinous and signet ring cell differentiation. Many of the identified molecular alterations have potential therapeutic relevance, including HER2 amplification, IDH1 mutation, and low frequency KRAS mutation.

  10. Controlled and localized delivery of c-myc AS-ODN to cells by 3-aminopropyl-trimethoxylsilane modified SBA-15 mesoporous silica

    Science.gov (United States)

    Zhang, Juan; Chen, Minmin; Zhao, Xiqiu; Zhang, Min; Mao, Jinxiang; Cao, Xichuan; Zhang, Zhuoqi

    2018-01-01

    SBA-15 mesoporous silicate was synthesized and functionalized with 3-aminopropyl organic groups through a post-synthesis method. The materials were characterized consecutively by powder X-ray diffraction (XRD), N2 adsorption/desorption analysis and solid-state magic-angle spinning 29Si nuclear magnetic resonance (MAS NMR). Human c-myc anti-sense oligodeoxyneucleotide (AS-ODN) was selected as a model molecule to be loaded onto the surface of bare and functionalized SBA-15 via different loading conditions. It has been found that the amount of AS-ODN incorporated into the porous matrix is strongly dependent on the surface properties, pH of the loading solvent and AS-ODN concentration. The release behaviour of AS-ODN from modified SBA-15 materials was also investigated and depended on conditions chosen. Cellular uptake of the eluted AS-ODN into Hela cells was observed by fluorescent microscopy. The materials showed excellent cytocompatibility. The AS-ODN keeps full transfection and expression activities indicating its structural integrity. The functionalized SBA-15 is an excellent prospect as a biomedical material candidate for the future.

  11. CDK-mediated activation of the SCF(FBXO) (28) ubiquitin ligase promotes MYC-driven transcription and tumourigenesis and predicts poor survival in breast cancer.

    Science.gov (United States)

    Cepeda, Diana; Ng, Hwee-Fang; Sharifi, Hamid Reza; Mahmoudi, Salah; Cerrato, Vanessa Soto; Fredlund, Erik; Magnusson, Kristina; Nilsson, Helén; Malyukova, Alena; Rantala, Juha; Klevebring, Daniel; Viñals, Francesc; Bhaskaran, Nimesh; Zakaria, Siti Mariam; Rahmanto, Aldwin Suryo; Grotegut, Stefan; Nielsen, Michael Lund; Szigyarto, Cristina Al-Khalili; Sun, Dahui; Lerner, Mikael; Navani, Sanjay; Widschwendter, Martin; Uhlén, Mathias; Jirström, Karin; Pontén, Fredrik; Wohlschlegel, James; Grandér, Dan; Spruck, Charles; Larsson, Lars-Gunnar; Sangfelt, Olle

    2013-07-01

    SCF (Skp1/Cul1/F-box) ubiquitin ligases act as master regulators of cellular homeostasis by targeting key proteins for ubiquitylation. Here, we identified a hitherto uncharacterized F-box protein, FBXO28 that controls MYC-dependent transcription by non-proteolytic ubiquitylation. SCF(FBXO28) activity and stability are regulated during the cell cycle by CDK1/2-mediated phosphorylation of FBXO28, which is required for its efficient ubiquitylation of MYC and downsteam enhancement of the MYC pathway. Depletion of FBXO28 or overexpression of an F-box mutant unable to support MYC ubiquitylation results in an impairment of MYC-driven transcription, transformation and tumourigenesis. Finally, in human breast cancer, high FBXO28 expression and phosphorylation are strong and independent predictors of poor outcome. In conclusion, our data suggest that SCF(FBXO28) plays an important role in transmitting CDK activity to MYC function during the cell cycle, emphasizing the CDK-FBXO28-MYC axis as a potential molecular drug target in MYC-driven cancers, including breast cancer. © 2013 The Authors. Published by John Wiley and Sons, Ltd on behalf of EMBO.

  12. Are mice pigmentary genes throwing light on humans?

    Directory of Open Access Journals (Sweden)

    Bose S

    1993-01-01

    Full Text Available In this article the rapid advances made in the molecular genetics of inherited disorders of hypo and hyperpigmentation during the past three years are reviewed. The main focus is on studies in mice as compared to homologues in humans. The main hypomelanotic diseases included are, piebaldism (white spotting due to mutations of c-KIT, PDGF and MGF genes; vitiligo (microphathalmia mice mutations of c-Kit and c-fms genes; Waardenburg syndrome (splotch locus mutations of mice PAX-3 or human Hup-2 genes; albinism (mutations of tyrosinase genes, Menkes disease (Mottled mouse, premature graying (mutations in light/brown locus/gp75/ TRP-1; Griscelli disease (mutations in TRP-1 and steel; Prader-willi and Angelman syndromes, tyrosinase-positive oculocutaneous albinism and hypomelanosis of lto (mutations of pink-eyed dilution gene/mapping to human chromosomes 15 q 11.2 - q12; and human platelet storage pool deficiency diseases due to defects in pallidin, an erythrocyte membrane protein (pallid mouse / mapping to 4.2 pallidin gene. The genetic characterization of hypermelanosis includes, neurofibromatosis 1 (Café-au-lait spots and McCune-Albright Syndrome. Rapid evolving knowledge about pigmentary genes will increase further the knowledge about these hypo and hyperpigmentary disorders.

  13. Modeling Aggressive Medulloblastoma Using Human Induced Pluripotent Stem Cells

    Science.gov (United States)

    2017-09-01

    performed ChIP-PCR to confirm the binding of MYC to promoters of known MYC target genes, such as Prps1, Gart and Pfas (data not shown). Progress achieved...activated genes (e.g. Prps1, Gart and Pfas ) are upregulated in response to MYC induction. We have sequenced the RNA-seq libraries from two cell contexts

  14. Global gene expression profiling in human lung cells exposed to cobalt

    Energy Technology Data Exchange (ETDEWEB)

    Malard, V.; Berenguer, F.; Prat, O.; Ruat, S.; Steinmetz, G.; Quemeneur, E. [CEA VALRHO, Serv Biochim and Toxicol Nucl, DSV, iBEB, F-30207 Bagnols Sur Ceze (France)

    2007-06-06

    It has been estimated that more than 1 million workers in the United States are exposed to cobalt. Occupational exposure to {sup 59}Co occurs mainly via inhalation and leads to various lung diseases. Cobalt is classified by the IARC as a possible human carcinogen (group 2B). Although there is evidence for in vivo and in vitro toxicity, the mechanisms of cobalt-induced lung toxicity are not fully known. The purpose of this work was to identify potential signatures of acute cobalt exposure using a toxico-genomic approach. Data analysis focused on some cellular processes and protein targets that are thought to be relevant for carcinogenesis, transport and bio-marker research. Results: A time course transcriptome analysis was performed on A549 human pulmonary cells, leading to the identification of 85 genes which are repressed or induced in response to soluble 59 Co. A group of 29 of these genes, representing the main biological functions, was assessed by quantitative RT-PCR. The expression profiles of six of them were then tested by quantitative RT-PCR in a time-dependent manner and three modulations were confirmed by Western blotting. The 85 modulated genes include potential cobalt carriers (FBXL2, ZNT1, SLC12A5), tumor suppressors or transcription factors (MAZ, DLG1, MYC, AXL) and genes linked to the stress response (UBC, HSPCB, BN1P3L). We also identified nine genes coding for secreted proteins as candidates for bio-marker research. Of those, T1MP2 was found to be down-regulated and this modulation was confirmed, in a dose-dependent manner, at protein level in the supernatant of exposed cells. Conclusion: Most of these genes have never been described as related to cobalt stress and provide original hypotheses for further study of the effects of this metal ion on human lung epithelial cells. A putative bio-marker of cobalt toxicity was identified. (authors)

  15. cDNA cloning, sequence analysis, and chromosomal localization of the gene for human carnitine palmitoyltransferase

    International Nuclear Information System (INIS)

    Finocchiaro, G.; Taroni, F.; Martin, A.L.; Colombo, I.; Tarelli, G.T.; DiDonato, S.; Rocchi, M.

    1991-01-01

    The authors have cloned and sequenced a cDNA encoding human liver carnitine palmitoyltransferase an inner mitochondrial membrane enzyme that plays a major role in the fatty acid oxidation pathway. Mixed oligonucleotide primers whose sequences were deduced from one tryptic peptide obtained from purified CPTase were used in a polymerase chain reaction, allowing the amplification of a 0.12-kilobase fragment of human genomic DNA encoding such a peptide. A 60-base-pair (bp) oligonucleotide synthesized on the basis of the sequence from this fragment was used for the screening of a cDNA library from human liver and hybridized to a cDNA insert of 2255 bp. This cDNA contains an open reading frame of 1974 bp that encodes a protein of 658 amino acid residues including 25 residues of an NH 2 -terminal leader peptide. The assignment of this open reading frame to human liver CPTase is confirmed by matches to seven different amino acid sequences of tryptic peptides derived from pure human CPTase and by the 82.2% homology with the amino acid sequence of rat CPTase. The NH 2 -terminal region of CPTase contains a leucine-proline motif that is shared by carnitine acetyl- and octanoyltransferases and by choline acetyltransferase. The gene encoding CPTase was assigned to human chromosome 1, region 1q12-1pter, by hybridization of CPTase cDNA with a DNA panel of 19 human-hanster somatic cell hybrids

  16. Mxi1 and Mxi1-0 Antagonize N-Myc Function and Independently Mediate Apoptosis in Neuroblastoma

    Directory of Open Access Journals (Sweden)

    David A. Erichsen

    2015-02-01

    Full Text Available Neuroblastoma (NB is the third most common malignancy of childhood, and outcomes for children with advanced disease remain poor; amplification of the MYCN gene portends a particularly poor prognosis. Mxi1 antagonizes N-Myc by competing for binding to Max and E-boxes. Unlike N-Myc, Mxi1 mediates transcriptional repression and suppresses cell proliferation. Mxi1 and Mxi1-0 (an alternatively transcribed Mxi1 isoform share identical Max and DNA binding domains but differ in amino-terminal sequences. Because of the conservation of these critical binding domains, we hypothesized that Mxi1-0 antagonizes N-Myc activity similar to Mxi1. SHEP NB cells and SHEP cells stably transfected with MYCN (SHEP/MYCN were transiently transfected with vectors containing full-length Mxi1, full-length Mxi1-0, or the common Mxi domain encoded by exons 2 to 6 (ex2-6. After incubation in low serum, parental SHEP/MYCN cell numbers were reduced compared with SHEP cells. Activated caspase-3 staining and DNA fragmentation ELISA confirmed that SHEP/MYCN cells undergo apoptosis in low serum, while SHEP/MYCN cells transfected with Mxi1 or Mxi1-0 do not. However, SHEP/MYCN cells transfected with Mxi1 or Mxi1-0 and grown in normal serum showed proliferation rates similar to SHEP cells. Mxi ex2-6 did not affect cell number in low or normal serum, suggesting that amino terminal domains of Mxi1 and Mxi1-0 are critical for antagonism. In the absence of N-Myc, Mxi1 and Mxi1-0 induce apoptosis independently through the caspase-8–dependent extrinsic pathway, while N-Myc activates the caspase-9–dependent intrinsic pathway. Together, these data indicate that Mxi1 and Mxi1-0 antagonize N-Myc but also independently impact NB cell survival.

  17. File list: Oth.PSC.05.Myc.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.PSC.05.Myc.AllCell mm9 TFs and others Myc Pluripotent stem cell SRX266823,SRX21...3819,SRX213807,SRX213828,SRX266824 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.PSC.05.Myc.AllCell.bed ...

  18. File list: Oth.PSC.10.Myc.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.PSC.10.Myc.AllCell mm9 TFs and others Myc Pluripotent stem cell SRX266823,SRX21...3819,SRX213807,SRX213828,SRX266824 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.PSC.10.Myc.AllCell.bed ...

  19. File list: Oth.PSC.50.Myc.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.PSC.50.Myc.AllCell mm9 TFs and others Myc Pluripotent stem cell SRX266823,SRX21...3819,SRX213828,SRX213807,SRX266824 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.PSC.50.Myc.AllCell.bed ...

  20. File list: Oth.PSC.20.Myc.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.PSC.20.Myc.AllCell mm9 TFs and others Myc Pluripotent stem cell SRX266823,SRX21...3807,SRX213828,SRX213819,SRX266824 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.PSC.20.Myc.AllCell.bed ...

  1. Lactobacillus rhamnosus GG and its SpaC pilus adhesin modulate inflammatory responsiveness and TLR-related gene expression in the fetal human gut

    Science.gov (United States)

    Ganguli, Kriston; Collado, Maria Carmen; Rautava, Jaana; Lu, Lei; Satokari, Reetta; von Ossowski, Ingemar; Reunanen, Justus; de Vos, Willem M.; Palva, Airi; Isolauri, Erika; Salminen, Seppo; Walker, W. Allan; Rautava, Samuli

    2015-01-01

    Background Bacterial contact in utero modulates fetal and neonatal immune responses. Maternal probiotic supplementation reduces the risk of immune-mediated disease in the infant. We investigated the immunomodulatory properties of live Lactobacillus rhamnosus GG and its SpaC pilus adhesin in human fetal intestinal models. Methods TNF-α mRNA expression was measured by qPCR in a human fetal intestinal organ culture model exposed to live L. rhamnosus GG and proinflammatory stimuli. Binding of recombinant SpaC pilus protein to intestinal epithelial cells was assessed in human fetal intestinal organ culture and the human fetal intestinal epithelial cell line H4 by immunohistochemistry and immunofluorescence, respectively. TLR-related gene expression in fetal ileal organ culture after exposure to recombinant SpaC was assessed by qPCR. Results Live L. rhamnosus GG significantly attenuates pathogen-induced TNF-α mRNA expression in the human fetal gut. Recombinant SpaC protein was found to adhere to the fetal gut and to modulate varying levels of TLR-related gene expression. Conclusion The human fetal gut is responsive to luminal microbes. L. rhamnosus GG significantly attenuates fetal intestinal inflammatory responses to pathogenic bacteria. The L. rhamnosus GG pilus adhesin SpaC binds to immature human intestinal epithelial cells and directly modulates intestinal epithelial cell innate immune gene expression. PMID:25580735

  2. Combinatorial treatment of DNA and chromatin-modifying drugs cause cell death in human and canine osteosarcoma cell lines.

    Directory of Open Access Journals (Sweden)

    Venugopal Thayanithy

    Full Text Available Downregulation of microRNAs (miRNAs at the 14q32 locus stabilizes the expression of cMYC, thus significantly contributing to osteosarcoma (OS pathobiology. Here, we show that downregulation of 14q32 miRNAs is epigenetically regulated. The predicted promoter regions of miRNA clusters at 14q32 locus showed no recurrent patterns of differential methylation, but Saos2 cells showed elevated histone deacetylase (HDAC activity. Treatment with 4-phenylbutyrate increased acetylation of histones associated with 14q32 miRNAs, but interestingly, robust restoration of 14q32 miRNA expression, attenuation of cMYC expression, and induction of apoptosis required concomitant treatment with 5-Azacytidine, an inhibitor of DNA methylation. These events were associated with genome-wide gene expression changes including induction of pro-apoptotic genes and downregulation of cell cycle genes. Comparable effects were achieved in human and canine OS cells using the HDAC inhibitor suberoylanilide hydroxamic acid (SAHA/Vorinostat and the DNA methylation inhibitor Zebularine (Zeb, with significantly more pronounced cytotoxicity in cells whose molecular phenotypes were indicative of aggressive biological behavior. These results suggested that the combination of these chromatin-modifying drugs may be a useful adjuvant in the treatment of rapidly progressive OS.

  3. Effect of recombinant human erythropoietin expressions of apoptosis ...

    African Journals Online (AJOL)

    apoptosis genes in rats following traumatic brain injury. Xuesong Yuan1* ... ĸB)-, c-myc-, and Fas/Fasl-positive cells were identified in brain tissues by ... stem cells present in the bone marrow. ... neuronal regeneration [12], lowering toxicity of.

  4. Generation of Directly Converted Human Osteoblasts That Are Free of Exogenous Gene and Xenogenic Protein.

    Science.gov (United States)

    Yamamoto, Kenta; Sato, Yoshiki; Honjo, Kenichi; Ichioka, Hiroaki; Oseko, Fumishige; Sowa, Yoshihiro; Yamamoto, Toshiro; Kanamura, Narisato; Kishida, Tsunao; Mazda, Osam

    2016-11-01

    Generation of osteoblasts from human somatic cells may be applicable in an effective transplantation therapy against bone diseases. Recently we established a procedure to directly convert human fibroblasts into osteoblasts by transducing some transcription factor genes via retroviral vectors. However, retroviral vector-mediated transduction may potentially cause tumor formation from the infected cells, thus a non-viral gene transfection method may be more preferable for preparation of osteoblasts to be used for transplantation therapy. Here, we constructed a plasmid vector encoding Oct4, Osterix, and L-Myc that were an appropriate combination of transcription factors for this purpose. Osteoblast-like phenotypes including high alkaline phosphatase (ALP) activity, bone matrix production and osteoblast-specific gene expression were induced in normal human fibroblasts that were transfected with the plasmid followed by culturing in osteogenic medium. The plasmid-driven directly converted osteoblasts (p-dOBs) were obtained even in the absence of a xenogenic protein. The plasmid vector sequence had fallen out of the p-dOBs. The cells formed deposition of calcified bodies in situ after transplantation into mice. These results strongly suggest that p-dOBs can be put into practical use for a novel cell-based therapy against bone diseases. J. Cell. Biochem. 117: 2538-2545, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  5. Targeting MUC1-C suppresses polycomb repressive complex 1 in multiple myeloma.

    Science.gov (United States)

    Tagde, Ashujit; Markert, Tahireh; Rajabi, Hasan; Hiraki, Masayuki; Alam, Maroof; Bouillez, Audrey; Avigan, David; Anderson, Kenneth; Kufe, Donald

    2017-09-19

    The polycomb repressive complex 1 (PRC1) includes the BMI1, RING1 and RING2 proteins. BMI1 is required for survival of multiple myeloma (MM) cells. The MUC1-C oncoprotein is aberrantly expressed by MM cells, activates MYC and is also necessary for MM cell survival. The present studies show that targeting MUC1-C with (i) stable and inducible silencing and CRISPR/Cas9 editing and (ii) the pharmacologic inhibitor GO-203, which blocks MUC1-C function, downregulates BMI1, RING1 and RING2 expression. The results demonstrate that MUC1-C drives BMI1 transcription by a MYC-dependent mechanism. MUC1-C thus promotes MYC occupancy on the BMI1 promoter and thereby activates BMI1 expression. We also show that the MUC1-C→MYC pathway induces RING2 expression. Moreover, in contrast to BMI1 and RING2, we found that MUC1-C drives RING1 by an NF-κB p65-dependent mechanism. Targeting MUC1-C and thereby the suppression of these key PRC1 proteins was associated with downregulation of the PRC1 E3 ligase activity as evidenced by decreases in ubiquitylation of histone H2A. Targeting MUC1-C also resulted in activation of the PRC1-repressed tumor suppressor genes, PTEN, CDNK2A and BIM . These findings identify a heretofore unrecognized role for MUC1-C in the epigenetic regulation of MM cells.

  6. Wnt and Notch signaling pathway involved in wound healing by targeting c-Myc and Hes1 separately.

    Science.gov (United States)

    Shi, Yan; Shu, Bin; Yang, Ronghua; Xu, Yingbin; Xing, Bangrong; Liu, Jian; Chen, Lei; Qi, Shaohai; Liu, Xusheng; Wang, Peng; Tang, Jinming; Xie, Julin

    2015-06-16

    Wnt and Notch signaling pathways are critically involved in relative cell fate decisions within the development of cutaneous tissues. Moreover, several studies identified the above two pathways as having a significant role during wound healing. However, their biological effects during cutaneous tissues repair are unclear. We employed a self-controlled model (Sprague-Dawley rats with full-thickness skin wounds) to observe the action and effect of Wnt/β-catenin and Notch signalings in vivo. The quality of wound repair relevant to the gain/loss-of-function Wnt/β-catenin and Notch activation was estimated by hematoxylin-and-eosin and Masson staining. Immunofluorescence analysis and Western blot analysis were used to elucidate the underlying mechanism of the regulation of Wnt and Notch signaling pathways in wound healing. Meanwhile, epidermal stem cells (ESCs) were cultured in keratinocyte serum-free medium with Jaggedl or in DAPT (N-[(3,5-difluorophenyl)acetyl]-L-alanyl-2-phenyl]glycine-1,1-dimethylethyl) to investigate whether the interruption of Notch signaling contributes to the expression of Wnt/β-catenin signaling. The results showed that in vivo the gain-of-function Wnt/β-catenin and Notch activation extended the ability to promote wound closure. We further determined that activation or inhibition of Wnt signaling and Notch signaling can affect the proliferation of ESCs, the differentiation and migration of keratinocytes, and follicle regeneration by targeting c-Myc and Hes1, which ultimately lead to enhanced or delayed wound healing. Furthermore, Western blot analysis suggested that the two pathways might interact in vivo and in vitro. These results suggest that Wnt and Notch signalings play important roles in cutaneous repair by targeting c-Myc and Hes1 separately. What's more, interaction between the above two pathways might act as a vital role in regulation of wound healing.

  7. Complete cDNA sequence of human complement C1s and close physical linkage of the homologous genes C1s and C1r

    International Nuclear Information System (INIS)

    Tosi, M.; Duponchel, C.; Meo, T.; Julier, C.

    1987-01-01

    Overlapping molecular clones encoding the complement subcomponent C1s were isolated from a human liver cDNA library. The nucleotide sequence reconstructed from these clones spans about 85% of the length of the liver C1s messenger RNAs, which occur in three distinct size classes around 3 kilobases in length. Comparisons with the sequence of C1r, the other enzymatic subcomponent of C1, reveal 40% amino acid identity and conservation of all the cysteine residues. Beside the serine protease domain, the following sequence motifs, previously described in C1r, were also found in C1s: (a) two repeats of the type found in the Ba fragment of complement factor B and in several other complement but also noncomplement proteins, (b) a cysteine-rich segment homologous to the repeats of epidermal growth factor precursor, and (c) a duplicated segment found only in C1r and C1s. Differences in each of these structural motifs provide significant clues for the interpretation of the functional divergence of these interacting serine protease zymogens. Hybridizations of C1r and C1s probes to restriction endonuclease fragments of genomic DNA demonstrate close physical linkage of the corresponding genes. The implications of this finding are discussed with respect to the evolution of C1r and C1s after their origin by tandem gene duplication and to the previously observed combined hereditary deficiencies of Clr and Cls

  8. Gene expression changes induced by estrogen and selective estrogen receptor modulators in primary-cultured human endometrial cells: signals that distinguish the human carcinogen tamoxifen

    International Nuclear Information System (INIS)

    Pole, Jessica C.M.; Gold, Leslie I.; Orton, Terry; Huby, Russell; Carmichael, Paul L.

    2005-01-01

    Tamoxifen has long been the endocrine treatment of choice for women with breast cancer and is now employed for prophylactic use in women at high risk from breast cancer. Other selective estrogen receptor modulators (SERMs), such as raloxifene, mimic some of tamoxifen's beneficial effects and, like tamoxifen, exhibit a complex mixture of organ-specific estrogen agonist and antagonistic properties. However, accompanying the positive effects of tamoxifen has been the emergence of evidence for an increased risk of endometrial cancer associated with its use. A more complete understanding of the mechanism(s) of SERM carcinogenicity and endometrial effects is therefore required. We have sought to compare and characterise the transcript profile of tamoxifen, raloxifene and the agonist estradiol in human endometrial cells. Using primary cultures of human endometria, to best emulate the in vivo responses in a manageable in vitro system, we have shown 230 significant changes in gene expression for epithelial cultures and 83 in stromal cultures, either specific to 17β-estradiol, tamoxifen or raloxifene, or changed across more than one of the treatments. Considering the transcriptome as a whole, the endometrial responses to raloxifene or tamoxifen were more similar than either drug was to 17β-estradiol. Treatment of endometrial cultures with tamoxifen resulted in the largest number of gene changes relative to control cultures and a high proportion of genes associated with regulation of gene transcription, cell-cycle control and signal transduction. Tamoxifen-specific changes that might point towards mechanisms for its proliferative response in the endometrium included changes in retinoblastoma and c-myc binding proteins, the APCL, dihydrofolate reductase (DHFR) and E2F1 genes and other transcription factors. Tamoxifen was also found to give rise to the highest number of gene expression changes common to those that characterise malignant endometria. It is anticipated that this

  9. Effect of hrHPV infection on anti-apoptotic gene and pro-apoptotic gene expression in cervical cancer tissue

    Directory of Open Access Journals (Sweden)

    Min-Er Tang

    2016-09-01

    Full Text Available Objective: To study the effect of hrHPV infection on anti-apoptotic gene and pro-apoptotic gene expression in cervical cancer tissue. Methods: A total of 56 patients with cervical cancer, 94 cases of patients with cervical intraepithelial neoplasia and 48 cases of patients with chronic cervicitis who were treated in our hospital from May 2013 to December 2015 were selected for study and included in malignant group, precancerous lesion group and benign group respectively. hrHPV infection as well as the expression of anti-apoptotic genes and proapoptotic genes in cervical tissue were detected. Results: hrHPV infection rate and viral load in cervical tissue of malignant group were significantly higher than those of precancerous lesion group and benign group; P27 and p16 levels in cervical tissue of malignant group were significantly lower than those of precancerous lesion group and benign group, and K-ras, c-myc, Prdx4 and TNFAIP8 levels were significantly higher than those of precancerous lesion group and benign group; the greater the HPV virus load, the lower the p27 and p16 levels and the higher the K-ras, c-myc, Prdx4 and TNFAIP8 levels in cervical tissue. Conclusions: hrHPV infection can result in tumor suppressor genes p27 and p16 expression deletion and increase the expression of proto-oncogene and apoptosis-inhibiting genes, and it is associated with the occurrence and development of cervical cancer.

  10. MYC and MYCN amplification can be reliably assessed by aCGH in medulloblastoma.

    Science.gov (United States)

    Bourdeaut, Franck; Grison, Camille; Maurage, Claude-Alain; Laquerriere, Annie; Vasiljevic, Alexandre; Delisle, Marie-Bernadette; Michalak, Sophie; Figarella-Branger, Dominique; Doz, François; Richer, Wilfrid; Pierron, Gaelle; Miquel, Catherine; Delattre, Olivier; Couturier, Jérôme

    2013-04-01

    As prognostic factors, MYC and MYCN amplifications are routinely assessed in medulloblastomas. Fluorescence in situ hybridization (FISH) is currently considered as the technique of reference. Recently, array comparative genomic hybridization (aCGH) has been developed as an alternative technique to evaluate genomic abnormalities in other tumor types; however, this technique has not been widely adopted as a replacement for FISH in medulloblastoma. In this study, 34 tumors were screened by both FISH and aCGH. In all cases showing amplification by FISH, aCGH also unambiguously revealed the abnormality. The aCGH technique was also performed on tumors showing no amplification by FISH, and the absence of amplification was confirmed in all cases. Interestingly, one tumor showed a subclonal MYC amplification by FISH. This subclonal amplification was observed in approximately 20% of tumor cells and was clearly evident on aCGH. In conclusion, our analysis confirms that aCGH is as safe as FISH for the detection of MYC/MYCN gene amplification. Given its cost efficiency in comparison to two FISH tests and the global genomic information additionally provided by an aCGH experiment, this reproducible technique can be safely retained as an alternative to FISH for routine investigation of medulloblastoma. Copyright © 2013 Elsevier Inc. All rights reserved.

  11. Synsepalum dulcificum extracts exhibit cytotoxic activity on human colorectal cancer cells and upregulate c-fos and c-jun early apoptotic gene expression

    Directory of Open Access Journals (Sweden)

    Jichang Seong

    2018-01-01

    Full Text Available Objective: To explore cytotoxicity of Synsepalum dulcificum (S. dulcificum Daniell (Sapotaceae on human colon cancer (HCT-116 and HT-29, human monocytic leukemia (THP-1 and normal (HDFn cell lines, and its effect on the expression of early apoptotic genes, c-fos and c-jun. Methods: Leaf, stem and berry of S. dulcificum were separately extracted by using 2 solvents, 10% ethanol (EtOH and 80% methanol (MeOH. PrestoBlue® cell viability assay and qRT-PCR assay were conducted to examine the above objectives respectively. Results: Stem MeOH, stem EtOH, and berry EtOH extracts of S. dulcificum were cytotoxic to HCT-116 and HT-29 human colon cancer cells. For HCT-116, IC50 values of these 3 extracts were not significantly different (P>0.05 from that of the positive control bleomycin (IC50 of 33.57 μg/mL, while for HT-29, IC50 values of these 3 extracts were significantly lower (P<0.05 than that of bleomycin (IC50 of 25.24 μg/mL. None of the extracts were cytotoxic to the THP-1 monocytic leukemia cells and HDFn normal human dermal fibroblasts. For both HCT-116 and HT-29, these extracts significantly up-regulated (P<0.05 the expression of c-fos and c-jun compared to the untreated negative control. Conclusions: The results of this study suggest that cytotoxicity of stem MeOH, stem EtOH, and berry EtOH extracts of S. dulcificum on HCT-116 and HT-29 colon cancer cells is due to the induced apoptosis which is caused by the up-regulation of the expression of early apoptotic genes, c-fos and c-jun.

  12. C282Y-HFE gene variant affects cholesterol metabolism in human neuroblastoma cells.

    Science.gov (United States)

    Ali-Rahmani, Fatima; Huang, Michael A; Schengrund, C-L; Connor, James R; Lee, Sang Y

    2014-01-01

    Although disruptions in the maintenance of iron and cholesterol metabolism have been implicated in several cancers, the association between variants in the HFE gene that is associated with cellular iron uptake and cholesterol metabolism has not been studied. The C282Y-HFE variant is a risk factor for different cancers, is known to affect sphingolipid metabolism, and to result in increased cellular iron uptake. The effect of this variant on cholesterol metabolism and its possible relevance to cancer phenotype was investigated using wild type (WT) and C282Y-HFE transfected human neuroblastoma SH-SY5Y cells. Expression of C282Y-HFE in SH-SY5Y cells resulted in a significant increase in total cholesterol as well as increased transcription of a number of genes involved in its metabolism compared to cells expressing WT-HFE. The marked increase in expression of NPC1L1 relative to that of most other genes, was accompanied by a significant increase in expression of NPC1, a protein that functions in cholesterol uptake by cells. Because inhibitors of cholesterol metabolism have been proposed to be beneficial for treating certain cancers, their effect on the viability of C282Y-HFE neuroblastoma cells was ascertained. C282Y-HFE cells were significantly more sensitive than WT-HFE cells to U18666A, an inhibitor of desmosterol Δ24-reductase the enzyme catalyzing the last step in cholesterol biosynthesis. This was not seen for simvastatin, ezetimibe, or a sphingosine kinase inhibitor. These studies indicate that cancers presenting in carriers of the C282Y-HFE allele might be responsive to treatment designed to selectively reduce cholesterol content in their tumor cells.

  13. MicroRNA miR-308 regulates dMyc through a negative feedback loop in Drosophila

    Directory of Open Access Journals (Sweden)

    Kaveh Daneshvar

    2012-10-01

    The abundance of Myc protein must be exquisitely controlled to avoid growth abnormalities caused by too much or too little Myc. An intriguing mode of regulation exists in which Myc protein itself leads to reduction in its abundance. We show here that dMyc binds to the miR-308 locus and increases its expression. Using our gain-of-function approach, we show that an increase in miR-308 causes a destabilization of dMyc mRNA and reduced dMyc protein levels. In vivo knockdown of miR-308 confirmed the regulation of dMyc levels in embryos. This regulatory loop is crucial for maintaining appropriate dMyc levels and normal development. Perturbation of the loop, either by elevated miR-308 or elevated dMyc, caused lethality. Combining elevated levels of both, therefore restoring balance between miR-308 and dMyc levels, resulted in lower apoptotic activity and suppression of lethality. These results reveal a sensitive feedback mechanism that is crucial to prevent the pathologies caused by abnormal levels of dMyc.

  14. Multistage modeling of protein dynamics with monomeric Myc oncoprotein as an example.

    Science.gov (United States)

    Liu, Jiaojiao; Dai, Jin; He, Jianfeng; Niemi, Antti J; Ilieva, Nevena

    2017-03-01

    We propose to combine a mean-field approach with all-atom molecular dynamics (MD) into a multistage algorithm that can model protein folding and dynamics over very long time periods yet with atomic-level precision. As an example, we investigate an isolated monomeric Myc oncoprotein that has been implicated in carcinomas including those in colon, breast, and lungs. Under physiological conditions a monomeric Myc is presumed to be an example of intrinsically disordered proteins that pose a serious challenge to existing modeling techniques. We argue that a room-temperature monomeric Myc is in a dynamical state, it oscillates between different conformations that we identify. For this we adopt the Cα backbone of Myc in a crystallographic heteromer as an initial ansatz for the monomeric structure. We construct a multisoliton of the pertinent Landau free energy to describe the Cα profile with ultrahigh precision. We use Glauber dynamics to resolve how the multisoliton responds to repeated increases and decreases in ambient temperature. We confirm that the initial structure is unstable in isolation. We reveal a highly degenerate ground-state landscape, an attractive set towards which Glauber dynamics converges in the limit of vanishing ambient temperature. We analyze the thermal stability of this Glauber attractor using room-temperature molecular dynamics. We identify and scrutinize a particularly stable subset in which the two helical segments of the original multisoliton align in parallel next to each other. During the MD time evolution of a representative structure from this subset, we observe intermittent quasiparticle oscillations along the C-terminal α helix, some of which resemble a translating Davydov's Amide-I soliton. We propose that the presence of oscillatory motion is in line with the expected intrinsically disordered character of Myc.

  15. Characterization of human cardiac myosin heavy chain genes

    International Nuclear Information System (INIS)

    Yamauchi-Takihara, K.; Sole, M.J.; Liew, J.; Ing, D.; Liew, C.C.

    1989-01-01

    The authors have isolated and analyzed the structure of the genes coding for the α and β forms of the human cardiac myosin heavy chain (MYHC). Detailed analysis of four overlapping MYHC genomic clones shows that the α-MYHC and β-MYHC genes constitute a total length of 51 kilobases and are tandemly linked. The β-MYHC-encoding gene, predominantly expressed in the normal human ventricle and also in slow-twitch skeletal muscle, is located 4.5 kilobases upstream of the α-MYHC-encoding gene, which is predominantly expressed in normal human atrium. The authors have determined the nucleotide sequences of the β form of the MYHC gene, which is 100% homologous to the cardiac MYHC cDNA clone (pHMC3). It is unlikely that the divergence of a few nucleotide sequences from the cardiac β-MYHC cDNA clone (pHMC3) reported in a MYHC cDNA clone (PSMHCZ) from skeletal muscle is due to a splicing mechanism. This finding suggests that the same β form of the cardiac MYHC gene is expressed in both ventricular and slow-twitch skeletal muscle. The promoter regions of both α- and β-MYHC genes, as well as the first four coding regions in the respective genes, have also been sequenced. The sequences in the 5'-flanking region of the α- and β-MYHC-encoding genes diverge extensively from one another, suggesting that expression of the α- and β-MYHC genes is independently regulated

  16. Mithramycin is a gene-selective Sp1 inhibitor that identifies a biological intersection between cancer and neurodegeneration.

    Science.gov (United States)

    Sleiman, Sama F; Langley, Brett C; Basso, Manuela; Berlin, Jill; Xia, Li; Payappilly, Jimmy B; Kharel, Madan K; Guo, Hengchang; Marsh, J Lawrence; Thompson, Leslie Michels; Mahishi, Lata; Ahuja, Preeti; MacLellan, W Robb; Geschwind, Daniel H; Coppola, Giovanni; Rohr, Jürgen; Ratan, Rajiv R

    2011-05-04

    Oncogenic transformation of postmitotic neurons triggers cell death, but the identity of genes critical for degeneration remain unclear. The antitumor antibiotic mithramycin prolongs survival of mouse models of Huntington's disease in vivo and inhibits oxidative stress-induced death in cortical neurons in vitro. We had correlated protection by mithramycin with its ability to bind to GC-rich DNA and globally displace Sp1 family transcription factors. To understand how antitumor drugs prevent neurodegeneration, here we use structure-activity relationships of mithramycin analogs to discover that selective DNA-binding inhibition of the drug is necessary for its neuroprotective effect. We identify several genes (Myc, c-Src, Hif1α, and p21(waf1/cip1)) involved in neoplastic transformation, whose altered expression correlates with protective doses of mithramycin or its analogs. Most interestingly, inhibition of one these genes, Myc, is neuroprotective, whereas forced expression of Myc induces Rattus norvegicus neuronal cell death. These results support a model in which cancer cell transformation shares key genetic components with neurodegeneration.

  17. Combined MYC and P53 defects emerge at medulloblastoma relapse and define rapidly progressive, therapeutically targetable disease.

    Science.gov (United States)

    Hill, Rebecca M; Kuijper, Sanne; Lindsey, Janet C; Petrie, Kevin; Schwalbe, Ed C; Barker, Karen; Boult, Jessica K R; Williamson, Daniel; Ahmad, Zai; Hallsworth, Albert; Ryan, Sarra L; Poon, Evon; Robinson, Simon P; Ruddle, Ruth; Raynaud, Florence I; Howell, Louise; Kwok, Colin; Joshi, Abhijit; Nicholson, Sarah Leigh; Crosier, Stephen; Ellison, David W; Wharton, Stephen B; Robson, Keith; Michalski, Antony; Hargrave, Darren; Jacques, Thomas S; Pizer, Barry; Bailey, Simon; Swartling, Fredrik J; Weiss, William A; Chesler, Louis; Clifford, Steven C

    2015-01-12

    We undertook a comprehensive clinical and biological investigation of serial medulloblastoma biopsies obtained at diagnosis and relapse. Combined MYC family amplifications and P53 pathway defects commonly emerged at relapse, and all patients in this group died of rapidly progressive disease postrelapse. To study this interaction, we investigated a transgenic model of MYCN-driven medulloblastoma and found spontaneous development of Trp53 inactivating mutations. Abrogation of p53 function in this model produced aggressive tumors that mimicked characteristics of relapsed human tumors with combined P53-MYC dysfunction. Restoration of p53 activity and genetic and therapeutic suppression of MYCN all reduced tumor growth and prolonged survival. Our findings identify P53-MYC interactions at medulloblastoma relapse as biomarkers of clinically aggressive disease that may be targeted therapeutically. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  18. Induced pluripotency with endogenous and inducible genes

    International Nuclear Information System (INIS)

    Duinsbergen, Dirk; Eriksson, Malin; Hoen, Peter A.C. 't; Frisen, Jonas; Mikkers, Harald

    2008-01-01

    The recent discovery that two partly overlapping sets of four genes induce nuclear reprogramming of mouse and even human cells has opened up new possibilities for cell replacement therapies. Although the combination of genes that induce pluripotency differs to some extent, Oct4 and Sox2 appear to be a prerequisite. The introduction of four genes, several of which been linked with cancer, using retroviral approaches is however unlikely to be suitable for future clinical applications. Towards developing a safer reprogramming protocol, we investigated whether cell types that express one of the most critical reprogramming genes endogenously are predisposed to reprogramming. We show here that three of the original four pluripotency transcription factors (Oct4, Klf4 and c-Myc or MYCER TAM ) induced reprogramming of mouse neural stem (NS) cells exploiting endogenous SoxB1 protein levels in these cells. The reprogrammed neural stem cells differentiated into cells of each germ layer in vitro and in vivo, and contributed to mouse development in vivo. Thus a combinatorial approach taking advantage of endogenously expressed genes and inducible transgenes may contribute to the development of improved reprogramming protocols

  19. High susceptibility of metastatic cells derived from human prostate and colon cancer cells to TRAIL and sensitization of TRAIL-insensitive primary cells to TRAIL by 4,5-dimethoxy-2-nitrobenzaldehyde

    Directory of Open Access Journals (Sweden)

    Lee Jae-Won

    2011-04-01

    Full Text Available Abstract Background Tumor recurrence and metastasis develop as a result of tumors' acquisition of anti-apoptotic mechanisms and therefore, it is necessary to develop novel effective therapeutics against metastatic cancers. In this study, we showed the differential TRAIL responsiveness of human prostate adenocarcinoma PC3 and human colon carcinoma KM12 cells and their respective highly metastatic PC3-MM2 and KM12L4A sublines and investigated the mechanism underlying high susceptibility of human metastatic cancer cells to TRAIL. Results PC3-MM2 and KM12L4A cells with high level of c-Myc and DNA-PKcs were more susceptible to TRAIL than their poorly metastatic primary PC3 and KM12 cells, which was associated with down-regulation of c-FLIPL/S and Mcl-1 and up-regulation of the TRAIL receptor DR5 but not DR4 in both metastatic cells. Moreover, high susceptibility of these metastatic cells to TRAIL was resulted from TRAIL-induced potent activation of caspase-8, -9, and -3 in comparison with their primary cells, which led to cleavage and down-regulation of DNA-PKcs. Knockdown of c-Myc gene in TRAIL-treated PC3-MM2 cells prevented the increase of DR5 cell surface expression, caspase activation and DNA-PKcs cleavage and attenuated the apoptotic effects of TRAIL. Moreover, the suppression of DNA-PKcs level with siRNA in the cells induced the up-regulation of DR5 and active caspase-8, -9, and -3. We also found that 4,5-dimethoxy-2-nitrobenzaldehyde (DMNB, a specific inhibitor of DNA-PK, potentiated TRAIL-induced cytotoxicity and apoptosis in relatively TRAIL-insensitive PC3 and KM12 cells and therefore functioned as a TRAIL sensitizer. Conclusion This study showed the positive relationship between c-Myc expression in highly metastatic human prostate and colon cancer cells and susceptibility to TRAIL-induced apoptosis and therefore indicated that TRAIL might be used as an effective therapeutic modality for advanced metastatic cancers overexpressing c-Myc and

  20. Post-operative infection and sepsis in humans is associated with deficient gene expression of γc cytokines and their apoptosis mediators.

    LENUS (Irish Health Repository)

    White, Mary

    2011-06-01

    Lymphocyte homeostasis is dependent on the γc cytokines. We hypothesised that sepsis in humans is associated with differential gene expression of the γc cytokines and their associated apoptosis mediators.

  1. Structure of gene and pseudogenes of human apoferritin H

    Energy Technology Data Exchange (ETDEWEB)

    Costanzo, F; Colombo, M; Staempfli, S; Santoro, C; Marone, M; Frank, K; Delius, H; Cortese, R

    1986-01-24

    Ferritin is composed of two subunits, H and L. cDNA's coding for these proteins from human liver, lymphocytes and from the monocyte-like cell line U937 have been cloned and sequenced. Southern blot analysis on total human DNA reveals that there are many DNA segments hybridizing to the apoferritin H and L cDNA probes. In view of the tissue heterogeneity of ferritin molecules, it appeared possible that apoferritin molecules could be coded by a family of genes differentially expressed in various tissues. In this paper, the authors describe the cloning and sequencing of the gene coding for human apoferritin H. This gene has three introns; the exon sequence is identical to that of cDNAs isolated from human liver, lymphocytes, HeLa cells and endothelial cells. In addition they show that at least 15 intronless pseudogenes exist, with features suggesting that there were originated by reverse transcription and insertion. On the basis of these results they conclude that only one gene is responsible for the synthesis of the majority of apoferritin H mRNA in various tissues examined, and that probably all the other DNA segments hybridizing with apoferritin cDNA are pseudogenes.

  2. Cross-species hybridization of woodchuck hepatitis virus-induced hepatocellular carcinoma using human oligonucleotide microarrays

    Institute of Scientific and Technical Information of China (English)

    Paul W Anderson; Bud C Tennant; Zhenghong Lee

    2006-01-01

    AIM: To demonstrate the feasibility of using woodchuck samples on human microarrays, to provide insight into pathways involving positron emission tomography (PET) imaging tracers and to identify genes that could be potential molecular imaging targets for woodchuck hepatocellular carcinoma.METHODS: Labeled cRNA from woodchuck tissue samples were hybridized to Affymetrix U133 plus 2.0 GeneChips(R). Ten genes were selected for validation using quantitative RT-PCR and literature review was made.RESULTS: Testis enhanced gene transcript (BAX Inhibitor 1), alpha-fetoprotein, isocitrate dehydrogenase 3 (NAD+) beta, acetyl-CoA synthetase 2, carnitine palmitoyltransferase 2, and N-myc2 were up-regulated and spermidine/spermine N1-acetyltransferase was down-regulated in the woodchuck HCC. We also found previously published results supporting 8 of the 10 most up-regulated genes and all 10 of the 10 most downregulated genes.CONCLUSION: Many of our microarray results were validated using RT-PCR or literature search. Hence, we believe that woodchuck HCC and non-cancerous liver samples can be used on human microarrays to yield meaningful results.

  3. Targeting the human lysozyme gene on bovine αs1- casein gene ...

    African Journals Online (AJOL)

    ajl yemi

    2011-11-28

    Nov 28, 2011 ... Targeting an exogenous gene into a favorable gene locus and for expression under endogenous regulators is ... case, the expression of human lysozyme could be regulated by the endogenous cis-element of αs1- casein gene in .... Mouse mammary epithelial C127 cells (Cell Bank, Chinese. Academy of ...

  4. Nucleolus disassembly in mitosis and apoptosis: dynamic redistribution of phosphorylated-c-Myc, fibrillarin and Ki-67

    Directory of Open Access Journals (Sweden)

    C Soldani

    2009-06-01

    Full Text Available The nucleolus may undergo disassembly either reversibly during mitosis, or irreversibly in apoptosis, thus allowing the redistribution of the nucleolar proteins.We investigated here by immunocytochemistry the fate of three representative proteins, namely phosphorylated c-Myc, fibrillarin and Ki-67, and found that they behave independently in both processes: they relocate in distinct compartments during mitosis, whereas during apoptosis they may either be cleaved (Ki-67 or be extruded into the cytoplasm with a different kinetics and following an ordered, non chaotic program. The separation of these nucleolar proteins which occurs in early apoptotic nuclei continues also in the cytoplasm, and culminates in the final formation of apoptotic blebs containing different nucleolar proteins: this evidence confirms that the apoptotic bodies may be variable in size, content and surface reactivity, and include heterogeneous aggregates of nuclear proteins and/or nucleic acids.

  5. A viral long terminal repeat expressed in CD4+CD8+ precursors is downregulated in mature peripheral CD4-CD8+ or CD4+CD8- T cells.

    OpenAIRE

    Paquette, Y; Doyon, L; Laperrière, A; Hanna, Z; Ball, J; Sekaly, R P; Jolicoeur, P

    1992-01-01

    The long terminal repeat from a thymotropic mouse mammary tumor virus variant, DMBA-LV, was used to drive the expression of two reporter genes, murine c-myc and human CD4, in transgenic mice. Expression was observed specifically in thymic immature cells. Expression of c-myc in these cells induced oligoclonal CD4+ CD8+ T-cell thymomas. Expression of human CD4 was restricted to thymic progenitor CD4- CD8- and CD4+ CD8+ T cells and was shut off in mature CD4+ CD8- and CD4- CD8+ T cells, known to...

  6. Understanding Selective Downregulation of c-Myc Expression through Inhibition of General Transcription Regulators in Multiple Myeloma

    Science.gov (United States)

    2015-06-01

    We next tested whether BET bromodomain inhibition mitigated the acti- vation of proadhesion pathways in aortic endothelium, which oc- curs during the...tinuum of activity as Myc flickers on and off of weakly bound, weakly expressed promoters, but stays longer or more frequently at high output promoters

  7. Molecular and functional characterization of the promoter of ETS2, the human c-ets-2 gene

    International Nuclear Information System (INIS)

    Mavrothalassitis, G.J.; Watson, D.K.; Papas, T.S.

    1990-01-01

    The 5' end of the human c-ets-2 gene, ETS2, was cloned and characterized. The major transcription initiation start sites were identified, and the pertinent sequences surrounding the ETS2 promoter were determined. The promoter region of ETS2 does not possess typical TATA and CAAT elements. However, this promoter contains several repeat regions, as well as two consensus AP2 binding sites and three putative Sp1 sites. There is also a palindromic region similar to the serum response element of the c-fos gene, located 1,400 base pairs (bp) upstream from the first major transcription initiation site. A G+C-rich sequence (GC element) with dyad symmetry can be seen in the ETS2 promoter, immediately following an unusually long polypurine-polypyrimidine tract. A series of deletion fragments from the putative promoter region were ligated in front of the bacterial chloramphenicol acetyltransferase gene and tested for activity following transfection into HeLa cells. The 5' boundary of the region needed for maximum promoter activity was found to be 159 bp upstream of the major initiation site. The promoter of ETS2 (within the polypyrimidine tract) serves to illustrate an alternative structure that may be present in genes with TATA-less promoters

  8. Arabidopsis MYC Transcription Factors Are the Target of Hormonal Salicylic Acid/Jasmonic Acid Cross Talk in Response to Pieris brassicae Egg Extract.

    Science.gov (United States)

    Schmiesing, André; Emonet, Aurélia; Gouhier-Darimont, Caroline; Reymond, Philippe

    2016-04-01

    Arabidopsis (Arabidopsis thaliana) plants recognize insect eggs and activate the salicylic acid (SA) pathway. As a consequence, expression of defense genes regulated by the jasmonic acid (JA) pathway is suppressed and larval performance is enhanced. Cross talk between defense signaling pathways is common in plant-pathogen interactions, but the molecular mechanism mediating this phenomenon is poorly understood. Here, we demonstrate that egg-induced SA/JA antagonism works independently of the APETALA2/ETHYLENE RESPONSE FACTOR (AP2/ERF) transcription factor ORA59, which controls the ERF branch of the JA pathway. In addition, treatment with egg extract did not enhance expression or stability of JASMONATE ZIM-domain transcriptional repressors, and SA/JA cross talk did not involve JASMONATE ASSOCIATED MYC2-LIKEs, which are negative regulators of the JA pathway. Investigating the stability of MYC2, MYC3, and MYC4, three basic helix-loop-helix transcription factors that additively control jasmonate-related defense responses, we found that egg extract treatment strongly diminished MYC protein levels in an SA-dependent manner. Furthermore, we identified WRKY75 as a novel and essential factor controlling SA/JA cross talk. These data indicate that insect eggs target the MYC branch of the JA pathway and uncover an unexpected modulation of SA/JA antagonism depending on the biological context in which the SA pathway is activated. © 2016 American Society of Plant Biologists. All Rights Reserved.

  9. Alisertib added to rituximab and vincristine is synthetic lethal and potentially curative in mice with aggressive DLBCL co-overexpressing MYC and BCL2.

    Directory of Open Access Journals (Sweden)

    Daruka Mahadevan

    Full Text Available Pearson correlation coefficient for expression analysis of the Lymphoma/Leukemia Molecular Profiling Project (LLMPP demonstrated Aurora A and B are highly correlated with MYC in DLBCL and mantle cell lymphoma (MCL, while both Auroras correlate with BCL2 only in DLBCL. Auroras are up-regulated by MYC dysregulation with associated aneuploidy and resistance to microtubule targeted agents such as vincristine. Myc and Bcl2 are differentially expressed in U-2932, TMD-8, OCI-Ly10 and Granta-519, but only U-2932 cells over-express mutated p53. Alisertib [MLN8237 or M], a highly selective small molecule inhibitor of Aurora A kinase, was synergistic with vincristine [VCR] and rituximab [R] for inhibition of cell proliferation, abrogation of cell cycle checkpoints and enhanced apoptosis versus single agent or doublet therapy. A DLBCL (U-2932 mouse model showed tumor growth inhibition (TGI of ∼ 10-20% (p = 0.001 for M, VCR and M-VCR respectively, while R alone showed ∼ 50% TGI (p = 0.001. M-R and VCR-R led to tumor regression [TR], but relapsed 10 days after discontinuing therapy. In contrast, M-VCR-R demonstrated TR with no relapse >40 days after stopping therapy with a Kaplan-Meier survival of 100%. Genes that are modulated by M-VCR-R (CENP-C, Auroras play a role in centromere-kinetochore function in an attempt to maintain mitosis in the presence of synthetic lethality. Together, our data suggest that the interaction between alisertib plus VCR plus rituximab is synergistic and synthetic lethal in Myc and Bcl-2 co-expressing DLBCL. Alisertib plus vincristine plus rituximab [M-VCR-R] may represent a new strategy for DLBCL therapy.

  10. Alisertib added to rituximab and vincristine is synthetic lethal and potentially curative in mice with aggressive DLBCL co-overexpressing MYC and BCL2.

    Science.gov (United States)

    Mahadevan, Daruka; Morales, Carla; Cooke, Laurence S; Manziello, Ann; Mount, David W; Persky, Daniel O; Fisher, Richard I; Miller, Thomas P; Qi, Wenqing

    2014-01-01

    Pearson correlation coefficient for expression analysis of the Lymphoma/Leukemia Molecular Profiling Project (LLMPP) demonstrated Aurora A and B are highly correlated with MYC in DLBCL and mantle cell lymphoma (MCL), while both Auroras correlate with BCL2 only in DLBCL. Auroras are up-regulated by MYC dysregulation with associated aneuploidy and resistance to microtubule targeted agents such as vincristine. Myc and Bcl2 are differentially expressed in U-2932, TMD-8, OCI-Ly10 and Granta-519, but only U-2932 cells over-express mutated p53. Alisertib [MLN8237 or M], a highly selective small molecule inhibitor of Aurora A kinase, was synergistic with vincristine [VCR] and rituximab [R] for inhibition of cell proliferation, abrogation of cell cycle checkpoints and enhanced apoptosis versus single agent or doublet therapy. A DLBCL (U-2932) mouse model showed tumor growth inhibition (TGI) of ∼ 10-20% (p = 0.001) for M, VCR and M-VCR respectively, while R alone showed ∼ 50% TGI (p = 0.001). M-R and VCR-R led to tumor regression [TR], but relapsed 10 days after discontinuing therapy. In contrast, M-VCR-R demonstrated TR with no relapse >40 days after stopping therapy with a Kaplan-Meier survival of 100%. Genes that are modulated by M-VCR-R (CENP-C, Auroras) play a role in centromere-kinetochore function in an attempt to maintain mitosis in the presence of synthetic lethality. Together, our data suggest that the interaction between alisertib plus VCR plus rituximab is synergistic and synthetic lethal in Myc and Bcl-2 co-expressing DLBCL. Alisertib plus vincristine plus rituximab [M-VCR-R] may represent a new strategy for DLBCL therapy.

  11. Pluripotent stem cells reveal the developmental biology of human megakaryocytes and provide a source of platelets for clinical application.

    Science.gov (United States)

    Takayama, Naoya; Eto, Koji

    2012-10-01

    Human pluripotent stem cells [PSCs; including human embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs)] can infinitely proliferate in vitro and are easily accessible for gene manipulation. Megakaryocytes (MKs) and platelets can be created from human ESCs and iPSCs in vitro and represent a potential source of blood cells for transfusion and a promising tool for studying the human thrombopoiesis. Moreover, disease-specific iPSCs are a powerful tool for elucidating the pathogenesis of hematological diseases and for drug screening. In that context, we and other groups have developed in vitro MK and platelet differentiation systems from human pluripotent stem cells (PSCs). Combining this co-culture system with a drug-inducible gene expression system enabled us to clarify the novel role played by c-MYC during human thrombopoiesis. In the next decade, technical advances (e.g., high-throughput genomic sequencing) will likely enable the identification of numerous gene mutations associated with abnormal thrombopoiesis. Combined with such technology, an in vitro system for differentiating human PSCs into MKs and platelets could provide a novel platform for studying human gene function associated with thrombopoiesis.

  12. MYC expression and translocation analyses in low-grade and transformed follicular lymphoma

    NARCIS (Netherlands)

    Aukema, Sietse M.; van Pel, Roel; Nagel, Inga; Bens, Susanne; Siebert, Reiner; Rosati, Stefano; van den Berg, Eva; Bosga-Bouwer, Anneke G.; Kibbelaar, Robby E.; Hoogendoorn, Mels; van Imhoff, Gustaaf W.; Kluin-Nelemans, Hanneke C.; Kluin, Philip M.; Nijland, Marcel

    2017-01-01

    AimsLow-grade follicular lymphoma (FL) (grade 1/2, FL1/2) has an annual risk of transformation of approximate to 3%, which is associated with aberrations in CDKN2A/B, TP53, and MYC. As in diffuse large B-cell lymphoma, high MYC expression in transformed FL (tFL) might predict a MYC breakpoint.

  13. A deletion in the N-myc downstream regulated gene 1 (NDRG1 gene in Greyhounds with polyneuropathy.

    Directory of Open Access Journals (Sweden)

    Cord Drögemüller

    Full Text Available The polyneuropathy of juvenile Greyhound show dogs shows clinical similarities to the genetically heterogeneous Charcot-Marie-Tooth (CMT disease in humans. The pedigrees containing affected dogs suggest monogenic autosomal recessive inheritance and all affected dogs trace back to a single male. Here, we studied the neuropathology of this disease and identified a candidate causative mutation. Peripheral nerve biopsies from affected dogs were examined using semi-thin histology, nerve fibre teasing and electron microscopy. A severe chronic progressive mixed polyneuropathy was observed. Seven affected and 17 related control dogs were genotyped on the 50k canine SNP chip. This allowed us to localize the causative mutation to a 19.5 Mb interval on chromosome 13 by homozygosity mapping. The NDRG1 gene is located within this interval and NDRG1 mutations have been shown to cause hereditary motor and sensory neuropathy-Lom in humans (CMT4D. Therefore, we considered NDRG1 a positional and functional candidate gene and performed mutation analysis in affected and control Greyhounds. A 10 bp deletion in canine NDRG1 exon 15 (c.1080_1089delTCGCCTGGAC was perfectly associated with the polyneuropathy phenotype of Greyhound show dogs. The deletion causes a frame shift (p.Arg361SerfsX60 which alters several amino acids before a stop codon is encountered. A reduced level of NDRG1 transcript could be detected by RT-PCR. Western blot analysis demonstrated an absence of NDRG1 protein in peripheral nerve biopsy of an affected Greyhound. We thus have identified a candidate causative mutation for polyneuropathy in Greyhounds and identified the first genetically characterized canine CMT model which offers an opportunity to gain further insights into the pathobiology and therapy of human NDRG1 associated CMT disease. Selection against this mutation can now be used to eliminate polyneuropathy from Greyhound show dogs.

  14. Targeting eradication of malignant cells derived from human bone marrow mesenchymal stromal cells

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yingbin [Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing 400044 (China); School of Life Science, Southwest University, Chongqing 400715 (China); Cai, Shaoxi, E-mail: sxcai@cqu.edu.cn [Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing 400044 (China); Yang, Li [Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing 400044 (China); College of Pharmacy, Jinan University, Guangzhou 510632 (China); Yu, Shuhui [Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing 400044 (China); Library of Southwest University, Chongqing 400715 (China); Jiang, Jiahuan; Yan, Xiaoqing [Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing 400044 (China); Zhang, Haoxing [School of Life Science, Southwest University, Chongqing 400715 (China); Liu, Lan [Department of Laboratory of Medicine, Children' s Hospital of Chongqin Medical University, Chongqing 400014 (China); Liu, Qun [College of Life Science and Technology, Southwest University for Nationalities, Chengdu 610041 (China); Du, Jun [Center of Microbiology, Biochemistry, and Pharmacology, School of Pharmaceutical Science, Sun Yat-Sen University, Guangzhou 510080 (China); Cai, Shaohui [College of Pharmacy, Jinan University, Guangzhou 510632 (China); Sung, K.L. Paul [Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing 400044 (China); Departments of Orthopaedic Surgery and Bioengineering, University of California, SD 0412 (United States)

    2010-12-10

    Human bone marrow mesenchymal stromal cells (hBMSC) have been shown to participate in malignant transformation. However, hampered by the low frequency of malignant transformation of hBMSC, we do not yet know how to prevent malignant transformation of implanted hBMSC. In this study, in order to establish a model for the eradication of hBMSC-derived malignant cells, a gene fusion consisting of a human telomerase (hTERT) promoter modified with both c-Myc and myeloid zinc finger protein2 (MZF-2) binding elements and followed by the E. coli cytosine deaminase (CD) and luciferase genes was stably transferred into hBMSC via lentiviral transduction; n-phosphonacelyl-L-aspartic acid (PALA) selection was used to generate malignant cell colonies derived from transduced hBMSC after treatment with the carcinogenic reagent BPDE. Cells that were amplified after PALA selection were used for transplantation and 5-FC pro-drug cytotoxicity tests. The results showed that PALA-resistant malignant cells could be generated from hBMSC co-induced with lentiviral transduction and treatment with Benzo(a)pyrene Diol Epoxide (BPDE); the modification of c-Myc and MZF-2 binding elements could remarkably enhance the transcriptional activities of the hTERT promoter in malignant cells, whereas transcriptional activity was depressed in normal hBMSC; malignant cells stably expressing CD under the control of the modified hTERT promoter could be eliminated by 5-FC administration. This study has provided a method for targeted eradication of malignant cells derived from hBMSC.

  15. Targeting eradication of malignant cells derived from human bone marrow mesenchymal stromal cells

    International Nuclear Information System (INIS)

    Yang, Yingbin; Cai, Shaoxi; Yang, Li; Yu, Shuhui; Jiang, Jiahuan; Yan, Xiaoqing; Zhang, Haoxing; Liu, Lan; Liu, Qun; Du, Jun; Cai, Shaohui; Sung, K.L. Paul

    2010-01-01

    Human bone marrow mesenchymal stromal cells (hBMSC) have been shown to participate in malignant transformation. However, hampered by the low frequency of malignant transformation of hBMSC, we do not yet know how to prevent malignant transformation of implanted hBMSC. In this study, in order to establish a model for the eradication of hBMSC-derived malignant cells, a gene fusion consisting of a human telomerase (hTERT) promoter modified with both c-Myc and myeloid zinc finger protein2 (MZF-2) binding elements and followed by the E. coli cytosine deaminase (CD) and luciferase genes was stably transferred into hBMSC via lentiviral transduction; n-phosphonacelyl-L-aspartic acid (PALA) selection was used to generate malignant cell colonies derived from transduced hBMSC after treatment with the carcinogenic reagent BPDE. Cells that were amplified after PALA selection were used for transplantation and 5-FC pro-drug cytotoxicity tests. The results showed that PALA-resistant malignant cells could be generated from hBMSC co-induced with lentiviral transduction and treatment with Benzo(a)pyrene Diol Epoxide (BPDE); the modification of c-Myc and MZF-2 binding elements could remarkably enhance the transcriptional activities of the hTERT promoter in malignant cells, whereas transcriptional activity was depressed in normal hBMSC; malignant cells stably expressing CD under the control of the modified hTERT promoter could be eliminated by 5-FC administration. This study has provided a method for targeted eradication of malignant cells derived from hBMSC.

  16. Arabidopsis MYC Transcription Factors Are the Target of Hormonal Salicylic Acid/Jasmonic Acid Cross Talk in Response to Pieris brassicae Egg Extract1[OPEN

    Science.gov (United States)

    Schmiesing, André; Gouhier-Darimont, Caroline

    2016-01-01

    Arabidopsis (Arabidopsis thaliana) plants recognize insect eggs and activate the salicylic acid (SA) pathway. As a consequence, expression of defense genes regulated by the jasmonic acid (JA) pathway is suppressed and larval performance is enhanced. Cross talk between defense signaling pathways is common in plant-pathogen interactions, but the molecular mechanism mediating this phenomenon is poorly understood. Here, we demonstrate that egg-induced SA/JA antagonism works independently of the APETALA2/ETHYLENE RESPONSE FACTOR (AP2/ERF) transcription factor ORA59, which controls the ERF branch of the JA pathway. In addition, treatment with egg extract did not enhance expression or stability of JASMONATE ZIM-domain transcriptional repressors, and SA/JA cross talk did not involve JASMONATE ASSOCIATED MYC2-LIKEs, which are negative regulators of the JA pathway. Investigating the stability of MYC2, MYC3, and MYC4, three basic helix-loop-helix transcription factors that additively control jasmonate-related defense responses, we found that egg extract treatment strongly diminished MYC protein levels in an SA-dependent manner. Furthermore, we identified WRKY75 as a novel and essential factor controlling SA/JA cross talk. These data indicate that insect eggs target the MYC branch of the JA pathway and uncover an unexpected modulation of SA/JA antagonism depending on the biological context in which the SA pathway is activated. PMID:26884488

  17. Human embryonic stem cells handbook

    Directory of Open Access Journals (Sweden)

    Carlo Alberto Redi

    2013-03-01

    Full Text Available After the Nobel prize in physiology or medicine was awarded jointly to Sir John Gurdon and Shinya Yamanaka for the discovery that mature cells can be reprogrammed to become pluripotent it became imperative to write down the review for a book entirely devoted to human embryonic stem cells (hES, those cells that are a urgent need for researchers, those cells that rekindle the ethical debates and finally, last but not least, those cells whose study paved the way to obtain induced pluripotent stem cells by the OSKC’s Yamanaka method (the OSKC acronim refers, for those not familiar with the topic, to the four stemness genes used to transfect somatic fibroblasts: Oct4, Sox2, Klf4 and c-Myc....

  18. Brain cDNA clone for human cholinesterase

    International Nuclear Information System (INIS)

    McTiernan, C.; Adkins, S.; Chatonnet, A.; Vaughan, T.A.; Bartels, C.F.; Kott, M.; Rosenberry, T.L.; La Du, B.N.; Lockridge, O.

    1987-01-01

    A cDNA library from human basal ganglia was screened with oligonucleotide probes corresponding to portions of the amino acid sequence of human serum cholinesterase. Five overlapping clones, representing 2.4 kilobases, were isolated. The sequenced cDNA contained 207 base pairs of coding sequence 5' to the amino terminus of the mature protein in which there were four ATG translation start sites in the same reading frame as the protein. Only the ATG coding for Met-(-28) lay within a favorable consensus sequence for functional initiators. There were 1722 base pairs of coding sequence corresponding to the protein found circulating in human serum. The amino acid sequence deduced from the cDNA exactly matched the 574 amino acid sequence of human serum cholinesterase, as previously determined by Edman degradation. Therefore, our clones represented cholinesterase rather than acetylcholinesterase. It was concluded that the amino acid sequences of cholinesterase from two different tissues, human brain and human serum, were identical. Hybridization of genomic DNA blots suggested that a single gene, or very few genes coded for cholinesterase

  19. cDNA sequence of human transforming gene hst and identification of the coding sequence required for transforming activity

    International Nuclear Information System (INIS)

    Taira, M.; Yoshida, T.; Miyagawa, K.; Sakamoto, H.; Terada, M.; Sugimura, T.

    1987-01-01

    The hst gene was originally identified as a transforming gene in DNAs from human stomach cancers and from a noncancerous portion of stomach mucosa by DNA-mediated transfection assay using NIH3T3 cells. cDNA clones of hst were isolated from the cDNA library constructed from poly(A) + RNA of a secondary transformant induced by the DNA from a stomach cancer. The sequence analysis of the hst cDNA revealed the presence of two open reading frames. When this cDNA was inserted into an expression vector containing the simian virus 40 promoter, it efficiently induced the transformation of NIH3T3 cells upon transfection. It was found that one of the reading frames, which coded for 206 amino acids, was responsible for the transforming activity

  20. Chromosomal localization of the human diazepam binding inhibitor gene

    International Nuclear Information System (INIS)

    DeBernardi, M.A.; Crowe, R.R.; Mocchetti, I.; Shows, T.B.; Eddy, R.L.; Costa, E.

    1988-01-01

    The authors have used in situ chromosome hybridization and human-mouse somatic cell hybrids to map the gene(s) for human diazepam binding inhibitor (DBI), an endogenous putative modulator of the γ-aminobutyric acid receptor acting at the allosteric regulatory center of this receptor that includes the benzodiazepine recognition site. In 784 chromosome spreads hybridized with human DBI cDNA, the distribution of 1,476 labeled sites revealed a significant clustering of autoradiographic grains (11.3% of total label) on the long arm of chromosome 2 (2q). Furthermore, 63.5% of the grains found on 2q were located on 2q12-21, suggesting regional mapping of DBI gene(s) to this segment. Secondary hybridization signals were frequently observed on other chromosomes and they were statistically significant mainly for chromosomes 5, 6, 11, and 14. In addition, DNA from 32 human-mouse cell hybrids was digested with BamHI and probed with human DBI cDNA. A 3.5-kilobase band, which probably represents the human DBI gene, was assigned to chromosome 2. Four higher molecular weight bands, also detected in BamHI digests, could not be unequivocally assigned. A chromosome 2 location was excluded for the 27-, 13-, and 10-kilobase bands. These results assign a human DBI gene to chromosome 2 (2q12-21) and indicate that three of the four homologous sequences detected by the human DBI probe are located on three other chromosomes

  1. Haplotypes in the APOA1-C3-A4-A5 gene cluster affect plasma lipids in both humans and baboons

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Qian-fei; Liu, Xin; O' Connell, Jeff; Peng, Ze; Krauss, Ronald M.; Rainwater, David L.; VandeBerg, John L.; Rubin, Edward M.; Cheng, Jan-Fang; Pennacchio, Len A.

    2003-09-15

    Genetic studies in non-human primates serve as a potential strategy for identifying genomic intervals where polymorphisms impact upon human disease-related phenotypes. It remains unclear, however, whether independently arising polymorphisms in orthologous regions of non-human primates leads to similar variation in a quantitative trait found in both species. To explore this paradigm, we studied a baboon apolipoprotein gene cluster (APOA1/C3/A4/A5) for which the human gene orthologs have well established roles in influencing plasma HDL-cholesterol and triglyceride concentrations. Our extensive polymorphism analysis of this 68 kb gene cluster in 96 pedigreed baboons identified several haplotype blocks each with limited diversity, consistent with haplotype findings in humans. To determine whether baboons, like humans, also have particular haplotypes associated with lipid phenotypes, we genotyped 634 well characterized baboons using 16 haplotype tagging SNPs. Genetic analysis of single SNPs, as well as haplotypes, revealed an association of APOA5 and APOC3 variants with HDL cholesterol and triglyceride concentrations, respectively. Thus, independent variation in orthologous genomic intervals does associate with similar quantitative lipid traits in both species, supporting the possibility of uncovering human QTL genes in a highly controlled non-human primate model.

  2. α5-GABAA receptors negatively regulate MYC-amplified medulloblastoma growth

    Science.gov (United States)

    Sengupta, Soma; Weeraratne, Shyamal Dilhan; Sun, Hongyu; Phallen, Jillian; Rallapalli, Sundari K.; Teider, Natalia; Kosaras, Bela; Amani, Vladimir; Pierre-Francois, Jessica; Tang, Yujie; Nguyen, Brian; Yu, Furong; Schubert, Simone; Balansay, Brianna; Mathios, Dimitris; Lechpammer, Mirna; Archer, Tenley C.; Tran, Phuoc; Reimer, Richard J.; Cook, James M.; Lim, Michael; Jensen, Frances E.; Pomeroy, Scott L.; Cho, Yoon-Jae

    2013-01-01

    Neural tumors often express neurotransmitter receptors as markers of their developmental lineage. Although these receptors have been well characterized in electrophysiological, developmental and pharmacological settings, their importance in the maintenance and progression of brain tumors, and importantly, the effect of their targeting in brain cancers remains obscure. Here, we demonstrate high levels of GABR5, which encodes the α-subunit of the GABAA receptor complex, in aggressive MYC-driven, “Group 3” medulloblastomas. We hypothesized that modulation of α-GABAA receptors alters medulloblastoma cell survival and monitored biological and electrophysiological responses of GABR5-expressing medulloblastoma cells upon pharmacological targeting of the GABAA receptor. While antagonists, inverse agonists and non-specific positive allosteric modulators had limited effects on medulloblastoma cells, a highly specific and potent α5-GABAA receptor agonist, QHii066, resulted in marked membrane depolarization and a significant decrease in cell survival. This effect was GABR5 dependent and mediated through the induction of apoptosis as well as accumulation of cells in S and G2 phases of the cell cycle. Chemical genomic profiling of QHii066-treated medulloblastoma cells confirmed inhibition of MYC-related transcriptional activity and revealed an enrichment of HOX5 target gene expression. siRNA-mediated knockdown of HOX5 markedly blunted the response of medulloblastoma cells to QHii066. Furthermore, QHii066 sensitized GABR5 positive medulloblastoma cells to radiation and chemotherapy consistent with the role of HOX5 in directly regulating p53 expression and inducing apoptosis. Thus, our results provide novel insights into the synthetic lethal nature of α5-GABAA receptor activation in MYC-driven/Group 3 medulloblastomas and propose its targeting as a novel strategy for the management of this highly aggressive tumor. PMID:24196163

  3. α5-GABAA receptors negatively regulate MYC-amplified medulloblastoma growth.

    Science.gov (United States)

    Sengupta, Soma; Weeraratne, Shyamal Dilhan; Sun, Hongyu; Phallen, Jillian; Rallapalli, Sundari K; Teider, Natalia; Kosaras, Bela; Amani, Vladimir; Pierre-Francois, Jessica; Tang, Yujie; Nguyen, Brian; Yu, Furong; Schubert, Simone; Balansay, Brianna; Mathios, Dimitris; Lechpammer, Mirna; Archer, Tenley C; Tran, Phuoc; Reimer, Richard J; Cook, James M; Lim, Michael; Jensen, Frances E; Pomeroy, Scott L; Cho, Yoon-Jae

    2014-04-01

    Neural tumors often express neurotransmitter receptors as markers of their developmental lineage. Although these receptors have been well characterized in electrophysiological, developmental and pharmacological settings, their importance in the maintenance and progression of brain tumors and, importantly, the effect of their targeting in brain cancers remains obscure. Here, we demonstrate high levels of GABRA5, which encodes the α5-subunit of the GABAA receptor complex, in aggressive MYC-driven, "Group 3" medulloblastomas. We hypothesized that modulation of α5-GABAA receptors alters medulloblastoma cell survival and monitored biological and electrophysiological responses of GABRA5-expressing medulloblastoma cells upon pharmacological targeting of the GABAA receptor. While antagonists, inverse agonists and non-specific positive allosteric modulators had limited effects on medulloblastoma cells, a highly specific and potent α5-GABAA receptor agonist, QHii066, resulted in marked membrane depolarization and a significant decrease in cell survival. This effect was GABRA5 dependent and mediated through the induction of apoptosis as well as accumulation of cells in S and G2 phases of the cell cycle. Chemical genomic profiling of QHii066-treated medulloblastoma cells confirmed inhibition of MYC-related transcriptional activity and revealed an enrichment of HOXA5 target gene expression. siRNA-mediated knockdown of HOXA5 markedly blunted the response of medulloblastoma cells to QHii066. Furthermore, QHii066 sensitized GABRA5 positive medulloblastoma cells to radiation and chemotherapy consistent with the role of HOXA5 in directly regulating p53 expression and inducing apoptosis. Thus, our results provide novel insights into the synthetic lethal nature of α5-GABAA receptor activation in MYC-driven/Group 3 medulloblastomas and propose its targeting as a novel strategy for the management of this highly aggressive tumor.

  4. Stat1-independent regulation of gene expression in response to IFN-γ

    Science.gov (United States)

    Ramana, Chilakamarti V.; Gil, M. Pilar; Han, Yulong; Ransohoff, Richard M.; Schreiber, Robert D.; Stark, George R.

    2001-01-01

    Although Stat1 is essential for cells to respond fully to IFN-γ, there is substantial evidence that, in the absence of Stat1, IFN-γ can still regulate the expression of some genes, induce an antiviral state and affect cell growth. We have now identified many genes that are regulated by IFN-γ in serum-starved Stat1-null mouse fibroblasts. The proteins induced by IFN-γ in Stat1-null cells can account for the substantial biological responses that remain. Some genes are induced in both wild-type and Stat1-null cells and thus are truly Stat1-independent. Others are subject to more complex regulation in response to IFN-γ, repressed by Stat1 in wild-type cells and activated in Stat1-null cells. Many genes induced by IFN-γ in Stat1-null fibroblasts also are induced by platelet-derived growth factor in wild-type cells and thus are likely to be involved in cell proliferation. In mouse cells expressing the docking site mutant Y440F of human IFN-γ receptor subunit 1, the mouse Stat1 is not phosphorylated in response to human IFN-γ, but c-myc and c-jun are still induced, showing that the Stat1 docking site is not required for Stat1-independent signaling. PMID:11390994

  5. Regulation of gene expression in mammalian cells following ionizing radiation

    International Nuclear Information System (INIS)

    Boothman, D.A.; Lee, S.W

    1991-01-01

    Mammalian cells use a variety of mechanisms to control the expression of new gene transcrips elicited in response to ionizing radiation. Damage-induced proteins have been found which contain DNA binding sites located within the promoter regions of SV40 and human thymidine kinase genes. DNA binding proteins as well as proteins which bind to specific DNA lesions (e.g., XIP bp 175 binds specifically to X-ray-damaged DNA) may play a role in the initial recognition of DNA damage and may initiate DNA repair processes, along with new transcription. Mammalian gene expression after DNA damage is also regulated via the stabilization of preexisting mRNA transcripts. Stabilized mRNA transcripts are translated into protein products not previously present in the cell due to undefined posttranscriptional modifications. Thus far, the only example of mRNA stabilization following X-irradiation is the immediate induction of tissue-type plasminogen activator. Mammalian cells synthesize new mRNA transcripts indirect response to DNA damage. Using cDNA cloning, Northern RNA blotting and nuclear run-on techniques, the levels of a variety of known and previously unknown genes dramatically increase following X-irradiation. These genes/proteins now include; a) DNA binding transcripts factors, such as the UV-responsive element binding factors, ionizing radiation-induced DNA-binding proteins, and XIP bP 175; b) proto-oncogenes, such as c-fos, c-jun, and c-myc; c) several growth-related genes, (e.g., the gadd genes, protein kinase C, IL-1, and thymidine kinase); and d) a variety of other genes, including proteases, tumor necrosis factor-alpha, and DT diaphorase. Mammalian cells respond to X-irradiation by eliciting a very complex series of events resulting in the appearance of new genes and proteins. These gene products may affect DNA repair, adaptive responses, apoptosis, SOS-type mutagenic response, and/or carcinogenesis. (J.P.N.)

  6. Evidence that phosphatidylcholine-specific phospholipase C is a key molecule mediating insulin-induced enhancement of gene expression from human cytomegalovirus promoter in CHO cells

    OpenAIRE

    Zhang, Yingpei; Katakura, Yoshinori; Seto, Perry; Shirahata, Sanetaka

    1997-01-01

    The signal transduction from insulin to its receptors and Ras has been extensively studied, while little has been reported beyond these steps. We found that the expression of human interleukin 6 gene under the control of immediate early gene promoter of human cytomegalovirus was enhanced by insulin sitmulation in Chinese hamster ovary cells. The induction effect of insulin was not significantly affected by inhibitors or activators of conventional protein kinase C, cAMP dependent protein kinas...

  7. Enabling a robust scalable manufacturing process for therapeutic exosomes through oncogenic immortalization of human ESC-derived MSCs

    Directory of Open Access Journals (Sweden)

    Choo Andre

    2011-04-01

    Full Text Available Abstract Background Exosomes or secreted bi-lipid vesicles from human ESC-derived mesenchymal stem cells (hESC-MSCs have been shown to reduce myocardial ischemia/reperfusion injury in animal models. However, as hESC-MSCs are not infinitely expansible, large scale production of these exosomes would require replenishment of hESC-MSC through derivation from hESCs and incur recurring costs for testing and validation of each new batch. Our aim was therefore to investigate if MYC immortalization of hESC-MSC would circumvent this constraint without compromising the production of therapeutically efficacious exosomes. Methods The hESC-MSCs were transfected by lentivirus carrying a MYC gene. The transformed cells were analyzed for MYC transgene integration, transcript and protein levels, and surface markers, rate of cell cycling, telomerase activity, karyotype, genome-wide gene expression and differentiation potential. The exosomes were isolated by HPLC fractionation and tested in a mouse model of myocardial ischemia/reperfusion injury, and infarct sizes were further assessed by using Evans' blue dye injection and TTC staining. Results MYC-transformed MSCs largely resembled the parental hESC-MSCs with major differences being reduced plastic adherence, faster growth, failure to senesce, increased MYC protein expression, and loss of in vitro adipogenic potential that technically rendered the transformed cells as non-MSCs. Unexpectedly, exosomes from MYC-transformed MSCs were able to reduce relative infarct size in a mouse model of myocardial ischemia/reperfusion injury indicating that the capacity for producing therapeutic exosomes was preserved. Conclusion Our results demonstrated that MYC transformation is a practical strategy in ensuring an infinite supply of cells for the production of exosomes in the milligram range as either therapeutic agents or delivery vehicles. In addition, the increased proliferative rate by MYC transformation reduces the time

  8. Radioactive cDNA microarrys for gene expression profiles in antidepressant therapy

    International Nuclear Information System (INIS)

    Lee, M. S.; Han, B. J.; Cha, J. H.; Ryu, Y. M.; Shin, E. K.; Park, J. H.; Park, Y. H.; Kim, M. K.

    2002-01-01

    Using radioactive cDNA microarray, we investigated a pattern of gene regulation under treatment of antidepressant on patients of depressive disoder. Basic microarray technology was performed as previously described in our research. The bioinformatic selection of human cDNAs, which is specifically designed for psychiatry, neurology, and signal transduction, were arrayed on nylon membranes. Using with 33P-labeled probes, this method provided highly sensitive gene expression profiles of our interest including brain receptors, drug metabolism, and cellular signalings. Gene expression profiles were also classified into several categories in accordance with the gene-regulation of antidepressant. The gene profiles of our interest were significantly up- (16 genes, >2.0 of Z-ratio) or down- (24 genes, <-2.0 of Z ratio) regulated when compared the good responsed group with the bad-responsed one. Consequently, we demonstrated that radioactive human cDNA microarray is highly likely to be an efficient technology for evaluating the gene regulation of antidepressants, such as selective serotonin-reuptake inhibitors (SSRIs), by using high-throughput biotechnology

  9. A Proteogenomic Approach to Understanding MYC Function in Metastatic Medulloblastoma Tumors

    Directory of Open Access Journals (Sweden)

    Jerome A. Staal

    2016-10-01

    Full Text Available Brain tumors are the leading cause of cancer-related deaths in children, and medulloblastoma is the most prevalent malignant childhood/pediatric brain tumor. Providing effective treatment for these cancers, with minimal damage to the still-developing brain, remains one of the greatest challenges faced by clinicians. Understanding the diverse events driving tumor formation, maintenance, progression, and recurrence is necessary for identifying novel targeted therapeutics and improving survival of patients with this disease. Genomic copy number alteration data, together with clinical studies, identifies c-MYC amplification as an important risk factor associated with the most aggressive forms of medulloblastoma with marked metastatic potential. Yet despite this, very little is known regarding the impact of such genomic abnormalities upon the functional biology of the tumor cell. We discuss here how recent advances in quantitative proteomic techniques are now providing new insights into the functional biology of these aggressive tumors, as illustrated by the use of proteomics to bridge the gap between the genotype and phenotype in the case of c-MYC-amplified/associated medulloblastoma. These integrated proteogenomic approaches now provide a new platform for understanding cancer biology by providing a functional context to frame genomic abnormalities.

  10. Double-hit lymphoma demonstrating t(6;14;18)(p25;q32;q21), suggesting two independent dual-hit translocations, MYC/BCL-2 and IRF4/BCL-2.

    Science.gov (United States)

    Tabata, Rie; Yasumizu, Ryoji; Tabata, Chiharu; Kojima, Masaru

    2013-01-01

    Here, we report a rare case of double-hit lymphoma, demonstrating t(6;14;18)(p25;q32;q21), suggesting two independent dual-translocations, c-MYC/BCL-2 and IRF4/BCL-2. The present case had a rare abnormal chromosome, t(6;14;18)(p25;q32;q21), independently, in addition to known dual-hit chromosomal abnormalities, t(14;18)(q32;q21) and t(8;22)(q24;q11.2). Lymph node was characterized by a follicular and diffuse growth pattern with variously sized neoplastic follicles. The intrafollicular area was composed of centrocytes with a few centroblasts and the interfollicular area was occupied by uniformly spread medium- to large-sized lymphocytes. CD23 immunostaining demonstrated a disrupted follicular dendritic cell meshwork. The intrafollicular tumor cells had a germinal center phenotype with the expression of surface IgM, CD10, Bcl-2, Bcl-6, and MUM1/IRF4. However, the interfollicular larger cells showed plasmacytic differentiation with diminished CD20, Bcl-2, Bcl-6, and positive intracytoplasmic IgM, and co-expression of MUM1/IRF4 and CD138 with increased Ki-67-positive cells (> 90%). MUM1/IRF4 has been found to induce c-MYC expression, and in turn, MYC transactivates MUM1/IRF4, creating a positive autoregulatory feedback loop. On the other hand, MUM1/IRF4 functions as a tumor suppressor in c-MYC-induced B-cell leukemia. The present rare case arouses interest in view of the possible "dual" activation of both c-MYC and MUM1/IRF4 through two independent dual-translocations, c-MYC/BCL-2 and IRF4/BCL-2.

  11. FUNCTIONAL SPECIALIZATION OF DUPLICATED FLAVONOID BIOSYNTHESIS GENES IN WHEAT

    Directory of Open Access Journals (Sweden)

    Khlestkina E.

    2012-08-01

    Full Text Available Gene duplication followed by subfunctionalization and neofunctionalization is of a great evolutionary importance. In plant genomes, duplicated genes may result from either polyploidization (homoeologous genes or segmental chromosome duplications (paralogous genes. In allohexaploid wheat Triticum aestivum L. (2n=6x=42, genome BBAADD, both homoeologous and paralogous copies were found for the regulatory gene Myc encoding MYC-like transcriptional factor in the biosynthesis of flavonoid pigments, anthocyanins, and for the structural gene F3h encoding one of the key enzymes of flavonoid biosynthesis, flavanone 3-hydroxylase. From the 5 copies (3 homoeologous and 2 paralogous of the Myc gene found in T. aestivum, only one plays a regulatory role in anthocyanin biosynthesis, interacting complementary with another transcriptional factor (MYB-like to confer purple pigmentation of grain pericarp in wheat. The role and functionality of the other 4 copies of the Myc gene remain unknown. From the 4 functional copies of the F3h gene in T. aestivum, three homoeologues have similar function. They are expressed in wheat organs colored with anthocyanins or in the endosperm, participating there in biosynthesis of uncolored flavonoid substances. The fourth copy (the B-genomic paralogue is transcribed neither in wheat organs colored with anthocyanins nor in seeds, however, it’s expression has been noticed in roots of aluminium-stressed plants, where the three homoeologous copies are not active. Functional diversification of the duplicated flavonoid biosynthesis genes in wheat may be a reason for maintenance of the duplicated copies and preventing them from pseudogenization.The study was supported by RFBR (11-04-92707. We also thank Ms. Galina Generalova for technical assistance.

  12. Constitutive expression of pluripotency-associated genes in mesodermal progenitor cells (MPCs.

    Directory of Open Access Journals (Sweden)

    Simone Pacini

    Full Text Available BACKGROUND: We recently characterized a progenitor of mesodermal lineage (MPCs from the human bone marrow of adults or umbilical cord blood. These cells are progenitors able to differentiate toward mesenchymal, endothelial and cardiomyogenic lineages. Here we present an extensive molecular characterization of MPCs, from bone marrow samples, including 39 genes involved in stem cell machinery, differentiation and cell cycle regulation. METHODOLOGY/PRINCIPAL FINDINGS: MPCs are cytofluorimetrically characterized and quantitative RT-PCR was performed to evaluate the gene expression profile, comparing it with MSCs and hESCs lines. Immunofluorescence and dot-blot analysis confirm qRT-PCR data. MPCs exhibit an increased expression of OCT4, NANOG, SALL4, FBX15, SPP1 and to a lesser extent c-MYC and KLF4, but lack LIN28 and SOX2. MPCs highly express SOX15. CONCLUSIONS/SIGNIFICANCE: MPCs express many pluripotency-associated genes and show a peculiar Oct-4 molecular circuit. Understanding this unique molecular mechanism could lead to identifying MPCs as feasible, long telomeres, target cells for reprogramming with no up-regulation of the p53 pathway. Furthermore MPCs are easily and inexpensively harvested from human bone marrow.

  13. Anti-proliferative activity of the quassinoid NBT-272 in childhood medulloblastoma cells

    Directory of Open Access Journals (Sweden)

    Helson Lawrence

    2007-01-01

    Full Text Available Abstract Background With current treatment strategies, nearly half of all medulloblastoma (MB patients die from progressive tumors. Accordingly, the identification of novel therapeutic strategies remains a major goal. Deregulation of c-MYC is evident in numerous human cancers. In MB, over-expression of c-MYC has been shown to correlate with anaplasia and unfavorable prognosis. In neuroblastoma – an embryonal tumor with biological similarities to MB – the quassinoid NBT-272 has been demonstrated to inhibit cellular proliferation and to down-regulate c-MYC protein expression. Methods To study MB cell responses to NBT-272 and their dependence on the level of c-MYC expression, DAOY (wild-type, empty vector transfected or c-MYC transfected, D341 (c-MYC amplification and D425 (c-MYC amplification human MB cells were used. The cells were treated with different concentrations of NBT-272 and the impact on cell proliferation, apoptosis and c-MYC expression was analyzed. Results NBT-272 treatment resulted in a dose-dependent inhibition of cellular proliferation (IC50 in the range of 1.7 – 9.6 ng/ml and in a dose-dependent increase in apoptotic cell death in all human MB cell lines tested. Treatment with NBT-272 resulted in up to 90% down-regulation of c-MYC protein, as demonstrated by Western blot analysis, and in a significant inhibition of c-MYC binding activity. Anti-proliferative effects were slightly more prominent in D341 and D425 human MB cells with c-MYC amplification and slightly more pronounced in c-MYC over-expressing DAOY cells compared to DAOY wild-type cells. Moreover, treatment of synchronized cells by NBT-272 induced a marked cell arrest at the G1/S boundary. Conclusion In human MB cells, NBT-272 treatment inhibits cellular proliferation at nanomolar concentrations, blocks cell cycle progression, induces apoptosis, and down-regulates the expression of the oncogene c-MYC. Thus, NBT-272 may represent a novel drug candidate to inhibit

  14. S(+)-ibuprofen destabilizes MYC/MYCN and AKT, increases p53 expression, and induces unfolded protein response and favorable phenotype in neuroblastoma cell lines.

    Science.gov (United States)

    Ikegaki, Naohiko; Hicks, Sakeenah L; Regan, Paul L; Jacobs, Joshua; Jumbo, Amina S; Leonhardt, Payton; Rappaport, Eric F; Tang, Xao X

    2014-01-01

    Neuroblastoma is a common pediatric solid tumor that exhibits a striking clinical bipolarity: favorable and unfavorable. The survival rate of children with unfavorable neuroblastoma remains low among all childhood cancers. MYCN and MYC play a crucial role in determining the malignancy of unfavorable neuroblastomas, whereas high-level expression of the favorable neuroblastoma genes is associated with a good disease outcome and confers growth suppression of neuroblastoma cells. A small fraction of neuroblastomas harbors TP53 mutations at diagnosis, but a higher proportion of the relapse cases acquire TP53 mutations. In this study, we investigated the effect of S(+)-ibuprofen on neuroblastoma cell lines, focusing on the expression of the MYCN, MYC, AKT, p53 proteins and the favorable neuroblastoma genes in vitro as biomarkers of malignancy. Treatment of neuroblastoma cell lines with S(+)-ibuprofen resulted in a significant growth suppression. This growth effect was accompanied by a marked decrease in the expression of MYC, MYCN, AKT and an increase in p53 expression in neuroblastoma cell lines without TP53 mutation. In addition, S(+)-ibuprofen enhanced the expression of some favorable neuroblastoma genes (EPHB6, CD44) and genes involved in growth suppression and differentiation (EGR1, EPHA2, NRG1 and SEL1L). Gene expression profile and Ingenuity pathway analyses using TP53-mutated SKNAS cells further revealed that S(+)-ibuprofen suppressed molecular pathways associated with cell growth and conversely enhanced those of cell cycle arrest and the unfolded protein response. Collectively, these results suggest that S(+)-ibuprofen or its related compounds may have the potential for therapeutic and/or palliative use for unfavorable neuroblastoma.

  15. Molecular cloning of a cDNA and chromosomal localization of a human theta-class glutathione S-transferase gene (GSTT2) to chromosome 22

    Energy Technology Data Exchange (ETDEWEB)

    Tan, K.L.; Baker, R.T.; Board, P.G. [Australian National Univ., Canberra (Australia)] [and others

    1995-01-20

    Until recently the Theta-class glutathione S-transferases (GSTs) were largely overlooked due to their low activity with the model substrate 1-chloro-2,4-dinitrobenzene (CDNB) and their failure to bind to immobilized glutathione affinity matrices. Little is known about the number of genes in this class. Recently, Pemble et al. reported the cDNA cloning of a human Theta-class GST, termed GSTT1. In this study, we describe the molecular cloning of a cDNA encoding a second human Theta-class GST (GSTT2) from a {lambda}gt11 human liver 5{prime}-stretch cDNA library. The encoded protein contains 244 amino acids and has 78.3% sequence identity with the rat subunit 12 and only 55.0% identity with human GSTT1. GSTT2 has been mapped to chromosome 22 by somatic cell hybrid analysis. The precise position of the gene was localized to subband 22q11.2 by in situ hybridization. The absence of other regions of hybridization suggests that there are no closely related sequences (e.g., reverse transcribed pseudogenes) scattered throughout the genome and that if there are closely related genes, they must be clustered near GSTT2. Southern blot analysis of human DNA digested with BamHI shows that the size of the GSTT2 gene is relatively small, as the coding sequence falls within a 3.6-kb BamHI fragment. 35 refs., 6 figs.

  16. Generation of human iPSCs from an essential thrombocythemia patient carrying a V501L mutation in the MPL gene.

    Science.gov (United States)

    Liu, Senquan; Ye, Zhaohui; Gao, Yongxing; He, Chaoxia; Williams, Donna W; Moliterno, Alison; Spivak, Jerry; Huang, He; Cheng, Linzhao

    2017-01-01

    Activating point mutations in the MPL gene encoding the thrombopoietin receptor are found in 3%-10% of essential thrombocythemia (ET) and myelofibrosis patients. Here, we report the derivation of induced pluripotent stem cells (iPSCs) from an ET patient with a heterozygous MPL V501L mutation. Peripheral blood CD34 + progenitor cells were reprogrammed by transient plasmid expression of OCT4, SOX2, KLF4, c-MYC plus BCL2L1 (BCL-xL) genes. The derived line M494 carries a MPL V501L mutation, displays typical iPSC morphology and characteristics, are pluripotent and karyotypically normal. Upon differentiation, the iPSCs are able to differentiate into cells derived from three germ layers. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  17. Cooperative interplay of let-7 mimic and HuR with MYC RNA.

    Science.gov (United States)

    Gunzburg, Menachem J; Sivakumaran, Andrew; Pendini, Nicole R; Yoon, Je-Hyun; Gorospe, Myriam; Wilce, Matthew C J; Wilce, Jacqueline A

    2015-01-01

    Both RNA-binding proteins (RBP) and miRNA play important roles in the regulation of mRNA expression, often acting together to regulate a target mRNA. In some cases the RBP and miRNA have been reported to act competitively, but in other instances they function cooperatively. Here, we investigated HuR function as an enhancer of let-7-mediated translational repression of c-Myc despite the separation of their binding sites. Using an in vitro system, we determined that a let-7 mimic, consisting of single-stranded (ss)DNA complementary to the let-7 binding site, enhanced the affinity of HuR for a 122-nt MYC RNA encompassing both binding sites. This finding supports the biophysical principle of cooperative binding by an RBP and miRNA purely through interactions at distal mRNA binding sites.

  18. Direct conversion of human fibroblasts into functional osteoblasts by defined factors.

    Science.gov (United States)

    Yamamoto, Kenta; Kishida, Tsunao; Sato, Yoshiki; Nishioka, Keisuke; Ejima, Akika; Fujiwara, Hiroyoshi; Kubo, Toshikazu; Yamamoto, Toshiro; Kanamura, Narisato; Mazda, Osam

    2015-05-12

    Osteoblasts produce calcified bone matrix and contribute to bone formation and remodeling. In this study, we established a procedure to directly convert human fibroblasts into osteoblasts by transducing some defined factors and culturing in osteogenic medium. Osteoblast-specific transcription factors, Runt-related transcription factor 2 (Runx2), and Osterix, in combination with Octamer-binding transcription factor 3/4 (Oct4) and L-Myc (RXOL) transduction, converted ∼ 80% of the fibroblasts into osteocalcin-producing cells. The directly converted osteoblasts (dOBs) induced by RXOL displayed a similar gene expression profile as normal human osteoblasts and contributed to bone repair after transplantation into immunodeficient mice at artificial bone defect lesions. The dOBs expressed endogenous Runx2 and Osterix, and did not require continuous expression of the exogenous genes to maintain their phenotype. Another combination, Oct4 plus L-Myc (OL), also induced fibroblasts to produce bone matrix, but the OL-transduced cells did not express Osterix and exhibited a more distant gene expression profile to osteoblasts compared with RXOL-transduced cells. These findings strongly suggest successful direct reprogramming of fibroblasts into functional osteoblasts by RXOL, a technology that may provide bone regeneration therapy against bone disorders.

  19. Eco RI RFLP in the human IGF II gene

    Energy Technology Data Exchange (ETDEWEB)

    Cocozza, S; Garofalo, S; Robledo, R; Monticelli, A; Conti, A; Chiarotti, L; Frunzio, R; Bruni, C B; Varrone, S

    1988-03-25

    The probe was a 500 bp cDNA containing exons 2-3 and 4 of the human IGF II gene. The clone was isolated by screening a human liver cDNA library with synthetic oligonucleotides. Eco RI digestion of genomic DNA and hybridization with the IGF II probe detects a two allele polymorphism with allelic fragments of 13.5 kb and 10.5 kb. The frequency was studied 38 unrelated Caucasians: Human IGF II gene was localized on the short arm of chromosome 11 (p15) by in situ hybridization. Codominant segregation was observed in 2 Caucasian families (10 individuals).

  20. Annotating MYC status with 89Zr-transferrin imaging.

    Science.gov (United States)

    Holland, Jason P; Evans, Michael J; Rice, Samuel L; Wongvipat, John; Sawyers, Charles L; Lewis, Jason S

    2012-10-01

    A noninvasive technology that quantitatively measures the activity of oncogenic signaling pathways could have a broad impact on cancer diagnosis and treatment with targeted therapies. Here we describe the development of (89)Zr-desferrioxamine-labeled transferrin ((89)Zr-transferrin), a new positron emission tomography (PET) radiotracer that binds the transferrin receptor 1 (TFRC, CD71) with high avidity. The use of (89)Zr-transferrin produces high-contrast PET images that quantitatively reflect treatment-induced changes in MYC-regulated TFRC expression in a MYC-driven prostate cancer xenograft model. Moreover, (89)Zr-transferrin imaging can detect the in situ development of prostate cancer in a transgenic MYC prostate cancer model, as well as in prostatic intraepithelial neoplasia (PIN) before histological or anatomic evidence of invasive cancer. These preclinical data establish (89)Zr-transferrin as a sensitive tool for noninvasive measurement of oncogene-driven TFRC expression in prostate and potentially other cancers, with prospective near-term clinical application.

  1. MYC-rearranged lymphomas other than Burkitt: Comparison between R-CHOP and Burkitt-type immunochemotherapy.

    Science.gov (United States)

    Baptista, Maria Joao; Tapia, Gustavo; Hernández-Rivas, José-Ángel; Martínez-Trillos, Alejandra; Mate, José-Luis; Navarro, José-Tomás

    2017-10-23

    MYC-rearranged (MYC-R) lymphomas other than Burkitt lymphoma (BL) are very aggressive, with poor prognosis when treated with standard regimens. We aimed to study the characteristics and outcome of a series of MYC-R lymphomas comparing the treatment results between R-CHOP based and a specific intensive regimen for BL (BURKIMAB). Retrospective study of patients diagnosed with MYC-R. Translocations of MYC, BCL2 and BCL6 were evaluated by fluorescent in situ hybridization. Patients were treated with either, R-CHOP based immunochemotherapy or the Burkitt type regimen, BURKIMAB. Thirty-four MYC-R lymphoma cases were studied: 21 treated with R-CHOP and 13 treated with BURKIMAB. There were no differences in CR rate; 45% (9/20) for R-CHOP and 42% (5/12) for BURKIMAB (P=.99). Although overall survival (OS) and progression free survival (PFS) of BURKIMAB-treated patients were better than those of R-CHOP-treated (3y-OS: 46 vs. 24%; 3y-PFS: 46 vs. 10%), the differences were not statistically significant. MYC-R lymphomas show poor outcomes even when treated with intensive immunochemotherapy for BL. Copyright © 2017 Elsevier España, S.L.U. All rights reserved.

  2. Efficient procedure for transferring specific human genes into Chinese hamster cell mutants: interspecific transfer of the human genes encoding leucyl- and asparaginyl-tRNA synthetases

    International Nuclear Information System (INIS)

    Cirullo, R.E.; Dana, S.; Wasmuth, J.J.

    1983-01-01

    A simple and efficient procedure for transferring specific human genes into mutant Chinese hamster ovary cell recipients has been developed that does not rely on using calcium phosphate-precipitated high-molecular-weight DNA. Interspecific cell hybrids between human leukocytes and temperature-sensitive Chinese hamster cell mutants with either a thermolabile leucyl-tRNA synthetase or a thermolabile asparaginyl-tRNA synthetase were used as the starting material in these experiments. These hybrids contain only one or a few human chromosomes and require expression of the appropriate human aminoacyl-tRNA synthetase gene to grow at 39 degrees C. Hybrids were exposed to very high doses of gamma-irradiation to extensively fragment the chromosomes and re-fused immediately to the original temperature-sensitive Chinese hamster mutant, and secondary hybrids were isolated at 39 degrees C. Secondary hybrids, which had retained small fragments of the human genome containing the selected gene, were subjected to another round of irradiation, refusion, and selection at 39 degrees C to reduce the amount of human DNA even further. Using this procedure, Chinese hamster cell lines have been constructed that express the human genes encoding either asparaginyl- or leucyl-tRNA synthetase, yet less than 0.1% of their DNA is derived from the human genome, as quantitated by a sensitive dot-blot nucleic acid hybridization procedure

  3. Inactivation of Adenomatous Polyposis Coli Reduces Bile Acid/Farnesoid X Receptor Expression through Fxr gene CpG Methylation in Mouse Colon Tumors and Human Colon Cancer Cells.

    Science.gov (United States)

    Selmin, Ornella I; Fang, Changming; Lyon, Adam M; Doetschman, Tom C; Thompson, Patricia A; Martinez, Jesse D; Smith, Jeffrey W; Lance, Peter M; Romagnolo, Donato F

    2016-02-01

    The farnesoid X receptor (FXR) regulates bile acid (BA) metabolism and possesses tumor suppressor functions. FXR expression is reduced in colorectal tumors of subjects carrying inactivated adenomatous polyposis coli (APC). Identifying the mechanisms responsible for this reduction may offer new molecular targets for colon cancer prevention. We investigated how APC inactivation influences the regulation of FXR expression in colonic mucosal cells. We hypothesized that APC inactivation would epigenetically repress nuclear receptor subfamily 1, group H, member 4 (FXR gene name) expression through increased CpG methylation. Normal proximal colonic mucosa and normal-appearing adjacent colonic mucosa and colon tumors were collected from wild-type C57BL/6J and Apc-deficient (Apc(Min) (/+)) male mice, respectively. The expression of Fxr, ileal bile acid-binding protein (Ibabp), small heterodimer partner (Shp), and cyclooxygenase-2 (Cox-2) were determined by real-time polymerase chain reaction. In both normal and adjacent colonic mucosa and colon tumors, we measured CpG methylation of Fxr in bisulfonated genomic DNA. In vitro, we measured the impact of APC inactivation and deoxycholic acid (DCA) treatment on FXR expression in human colon cancer HCT-116 cells transfected with silencing RNA for APC and HT-29 cells carrying inactivated APC. In Apc(Min) (/+) mice, constitutive CpG methylation of the Fxrα3/4 promoter was linked to reduced (60-90%) baseline Fxr, Ibabp, and Shp and increased Cox-2 expression in apparently normal adjacent mucosa and colon tumors. Apc knockdown in HCT-116 cells increased cellular myelocytomatosis (c-MYC) and lowered (∼50%) FXR expression, which was further reduced (∼80%) by DCA. In human HCT-116 but not HT-29 colon cancer cells, DCA induced FXR expression and lowered CpG methylation of FXR. We conclude that the loss of APC function favors the silencing of FXR expression through CpG hypermethylation in mouse colonic mucosa and human colon cells

  4. Inhibition of carcinogen induced c-Ha-ras and c-fos proto-oncogenes expression by dietary curcumin

    Directory of Open Access Journals (Sweden)

    Lipigorngoson Suwiwek

    2001-01-01

    Full Text Available Abstract Background We investigated the chemopreventive action of dietary curcumin on 7,12-dimethylbenz(aanthracene (DMBA-initiated and 12,0-tetradecanoylphorbol-13-acetate (TPA-promoted skin tumor formation in Swiss albino mice. Curcumin, a yellow coloring matter isolated from roots of Curcuma longa Linn, is a phenolic compound possessing antioxidant, free radical scavenger, and antiinflammatory properties. It has been shown by previously reported work that TPA-induced skin tumors were inhibited by topical application of curcumin, and curcumin has been shown to inhibit a variety of biological activities of TPA. Topical application of curcumin was reported to inhibit TPA-induced c-fos, c-jun and c-myc gene expression in mouse skin. This paper reports the effects of orally administered curcumin, which was consumed as a dietary component at concentrations of 0.2 % or 1 %, in ad libitum feeding. Results Animals in which tumors had been initiated with DMBA and promoted with TPA experienced significantly fewer tumors and less tumor volume if they ingested either 0.2% or 1% curcumin diets. Also, the dietary consumption of curcumin resulted in a significantly decreased expression of ras and fos proto-oncogenes in the tumorous skin, as measured by enhanced chemiluminesence Western blotting detection system (Amersham. Conclusions Whereas earlier work demonstrated that topical application of curcumin to mouse skin inhibited TPA-induced expression of c-fos, c-jun and c-myc oncogenes, our results are the first to show that orally consumed curcumin significantly inhibited DMBA- and TPA-induced ras and fos gene expression in mouse skin.

  5. Inhibition of carcinogen induced c-Ha-ras and c-fos proto-oncogenes expression by dietary curcumin

    International Nuclear Information System (INIS)

    Limtrakul, Porn-ngarm; Anuchapreeda, Songyot; Lipigorngoson, Suwiwek; Dunn, Floyd W

    2001-01-01

    We investigated the chemopreventive action of dietary curcumin on 7,12-dimethylbenz(a)anthracene (DMBA)-initiated and 12,0-tetradecanoylphorbol-13-acetate (TPA)-promoted skin tumor formation in Swiss albino mice. Curcumin, a yellow coloring matter isolated from roots of Curcuma longa Linn, is a phenolic compound possessing antioxidant, free radical scavenger, and antiinflammatory properties. It has been shown by previously reported work that TPA-induced skin tumors were inhibited by topical application of curcumin, and curcumin has been shown to inhibit a variety of biological activities of TPA. Topical application of curcumin was reported to inhibit TPA-induced c-fos, c-jun and c-myc gene expression in mouse skin. This paper reports the effects of orally administered curcumin, which was consumed as a dietary component at concentrations of 0.2 % or 1 %, in ad libitum feeding. Animals in which tumors had been initiated with DMBA and promoted with TPA experienced significantly fewer tumors and less tumor volume if they ingested either 0.2% or 1% curcumin diets. Also, the dietary consumption of curcumin resulted in a significantly decreased expression of ras and fos proto-oncogenes in the tumorous skin, as measured by enhanced chemiluminesence Western blotting detection system (Amersham). Whereas earlier work demonstrated that topical application of curcumin to mouse skin inhibited TPA-induced expression of c-fos, c-jun and c-myc oncogenes, our results are the first to show that orally consumed curcumin significantly inhibited DMBA- and TPA-induced ras and fos gene expression in mouse skin

  6. Molecular Cloning and Characterization of a Novel Human Glycine-N-acyltransferase Gene GLYATL1, Which Activates Transcriptional Activity of HSE Pathway

    Directory of Open Access Journals (Sweden)

    Long Yu

    2007-05-01

    Full Text Available The glycine-N-acyltransferase (GLYAT is well known to be involved in thedetoxification of endogenous and exogenous xenobiotic acyl-CoA's in mammals.Unfortunately, the knowledge about the gene encoding GLYAT is very limited. Here wereport a novel gene encoding a GLYAT member, designated as GLYATL1, which was1546 base pairs in length and contained an open reading frame (ORF encoding apolypeptide of 302 amino acids. GLYATL1 was a split gene that was consisted of 7 exonsand 6 introns and mapped to chromosome 11q12.1. The expression of GLYATL1 could befound in liver, kidney, pancreas, testis, ovary and stomach among 18 human tissues by RT-PCR analysis. Subcellular localization of myc-tagged GLYATL1 fusion protein revealedthat GLYATL1 was distributed primarily in the cytoplasm of COS-7 cells. Furthermore,through the pathway profiling assay, the GLYATL1 protein was found to activate HSEsignaling pathway in a dose-dependent manner when overexpressed in HEK293T cells.

  7. Expression analysis of the N-Myc downstream-regulated gene 1 indicates that myelinating Schwann cells are the primary disease target in hereditary motor and sensory neuropathy-Lom.

    Science.gov (United States)

    Berger, Philipp; Sirkowski, Erich E; Scherer, Steven S; Suter, Ueli

    2004-11-01

    Mutations in the gene encoding N-myc downstream-regulated gene-1 (NDRG1) lead to truncations of the encoded protein and are associated with an autosomal recessive demyelinating neuropathy--hereditary motor and sensory neuropathy-Lom. NDRG1 protein is highly expressed in peripheral nerve and is localized in the cytoplasm of myelinating Schwann cells, including the paranodes and Schmidt-Lanterman incisures. In contrast, sensory and motor neurons as well as their axons lack NDRG1. NDRG1 mRNA levels in developing and injured adult sciatic nerves parallel those of myelin-related genes, indicating that the expression of NDRG1 in myelinating Schwann cells is regulated by axonal interactions. Oligodendrocytes also express NDRG1, and the subtle CNS deficits of affected patients may result from a lack of NDRG1 in these cells. Our data predict that the loss of NDRG1 leads to a Schwann cell autonomous phenotype resulting in demyelination, with secondary axonal loss.

  8. Different mutations of the human c-mpl gene indicate distinct haematopoietic diseases.

    Science.gov (United States)

    He, Xin; Chen, Zhigang; Jiang, Yangyan; Qiu, Xi; Zhao, Xiaoying

    2013-01-25

    The human c-mpl gene (MPL) plays an important role in the development of megakaryocytes and platelets as well as the self-renewal of haematopoietic stem cells. However, numerous MPL mutations have been identified in haematopoietic diseases. These mutations alter the normal regulatory mechanisms and lead to autonomous activation or signalling deficiencies. In this review, we summarise 59 different MPL mutations and classify these mutations into four different groups according to the associated diseases and mutation rates. Using this classification, we clearly distinguish four diverse types of MPL mutations and obtain a deep understand of their clinical significance. This will prove to be useful for both disease diagnosis and the design of individual therapy regimens based on the type of MPL mutations.

  9. Characterization of a human MSX-2 cDNA and its fragment isolated as a transformation suppressor gene against v-Ki-ras oncogene.

    Science.gov (United States)

    Takahashi, C; Akiyama, N; Matsuzaki, T; Takai, S; Kitayama, H; Noda, M

    1996-05-16

    A cDNA (termed CT124) encoding a carboxyl-terminal fragment of the human homeobox protein MSX-2 was found to induce flat reversion when expressed in v-Ki-ras-transformed NIH3T3 cells. Although the expression of endogenous MSX-2 gene is low in most of the normal adult tissues examined, it is frequently activated in carcinoma-derived cell lines. Likewise, the gene is inactive in NIH3T3 cells but is transcriptionally activated after transformation by v-Ki-ras oncogene, suggesting that the intact MSX-2 may play a positive, rather than suppressive, role in cell transformation. To test this possibility, we isolated a near full-length human MSX-2 cDNA and tested its activities in two cell systems, i.e. fibroblast and myoblast. In NIH3T3 fibroblasts, although the gene by itself failed to confer a transformed phenotype, antisense MSX-2 cDNA as well as truncated CT124 cDNA interfered with the transforming activities of v-Ki-ras oncogene. In C2C12 myoblasts, MSX-2 was found to suppress MyoD gene expression, as do activated ras oncogenes, under certain culture conditions, and CT124 was found to inhibit the activities of both MSX-2 and ras in this system as well. Our findings not only suggest that CT124 may act as a dominant suppressor of MSX-2 but also raise the possibility that MSX-2 gene may be an important downstream target for the Ras signaling pathways.

  10. Effects of JS-K, a novel anti-cancer nitric oxide prodrug, on gene expression in human hepatoma Hep3B cells.

    Science.gov (United States)

    Dong, Ray; Wang, Xueqian; Wang, Huan; Liu, Zhengyun; Liu, Jie; Saavedra, Joseph E

    2017-04-01

    JS-K is a novel anticancer nitric oxide (NO) prodrug effective against a variety of cancer cells, including the inhibition of AM-1 hepatoma cell growth in rats. To further evaluate anticancer effects of JS-K, human hepatoma Hep3B cells were treated with JS-K and the compound control JS-43-126 at various concentrations (0-100μM) for 24h, and cytotoxicity was determined by the MTS assay. The compound control JS-43-126 was not cytotoxic to Hep3B cells at concentrations up to 100μM, while the LC 50 for JS-K was about 10μM. To examine the molecular mechanisms of antitumor effects of JS-K, Hep3B cells were treated with 1-10μM of JS-K for 24h, and then subjected to gene expression analysis via real time RT-PCR and protein immunostain via confocal images. JS-K is a GST-α targeting NO prodrug, and decreased immunostaining for GST-α was associated with JS-K treatment. JS-K activated apoptosis pathways in Hep3B cells, including induction of caspase-3, caspase-9, Bax, TNF-α, and IL-1β, and immunostaining for caspase-3 was intensified. The expressions of thrombospondin-1 (TSP-1) and the tissue inhibitors of metalloproteinase-1 (TIMP-1) were increased by JS-K at both transcript and protein levels. JS-K treatment also increased the expression of differentiation-related genes CD14 and CD11b, and depressed the expression of c-myc in Hep3B cells. Thus, multiple molecular events appear to be associated with anticancer effects of JS-K in human hepatoma Hep3B cells, including activation of genes related to apoptosis and induction of genes involved in antiangiogenesis and tumor cell migration. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  11. The Effect of Coexistence of a Pair of Mutated Oncogenes on the Survival Rate of Invasive Breast Carcinoma Patients

    Science.gov (United States)

    Nair, D. R.

    2017-12-01

    The purpose of this project was to determine the effect of two mutated oncogenes on the survival rate from invasive breast carcinoma when in comparison to the mutation of a single oncogene on the survival rate. An oncogene is defined as a gene, that when mutated, can lead to cancer. The two oncogenes used in this project were human epidermal growth factor receptor 2 (HER2) and c-myc (MYC). HER2 and MYC are both oncogenes that contribute to the formation of cancer. HER2 proteins are receptors on breast cells, and when the HER2 gene is mutated, there is an overexpression of HER2 protein on the breast cell. This makes the breast cells proliferate uncontrollably. MYC is a gene that codes for a transcription factor that plays a role in cell cycle progression. The overexpression of MYC also leads to the proliferation of cells. I hypothesized that if there is a mutation in both the MYC and HER2 genes, then the survival rate of invasive breast carcinoma patients will be lower compared to patients with the mutations of only MYC or HER2. To test this hypothesis, we conducted individual gene searches in CBioPortal for HER2 in the datasets from the studies titled TCGA Nature 2012, TCGA Cell 2015, and TCGA Provisional. We conducted individual gene searches in CBioPortal for MYC in the same datasets. The survival rate data was then exported and analyzed for patients with mutations of either HER2 or MYC and with mutations of both genes. To determine the cases that had both HER2 and MYC mutations, we found the overlapping cases in both HER2 and MYC groups for all three datasets. We calculated the median of the survival data for cases where either HER2 or MYC was mutated and cases where both MYC and HER2 were mutated. From the first dataset, the median of MYC data was 95.53, HER2 data was 95.83, and both HER2 and MYC data was 91.24. In the second dataset, the median of MYC data was 92.17 , HER2 data was 93.5, and both HER2 and MYC data was 87.95 . In the third dataset, the median

  12. Soluble expression of recomb inant cMyc, Klf4, Oct4, and Sox2 proteins in bacteria and transduction into living cells

    Directory of Open Access Journals (Sweden)

    Guo-Dan Liu

    2017-04-01

    Full Text Available AIM: To develop a new method to produce recombinant reprogramming proteins, cMyc, Klf4, Oct4, and Sox2, in soluble format with low cost for the generation of induced pluripotent stem cells (iPSCs. METHODS: A short polypeptide sequence derived from the HIV trans-activator of transcription protein (TAT and the nucleus localization signal (NLS polypeptide were fused to the N terminus of the reprogramming proteins and they were constructed into pCold-SUMO vector which can extremely improve the solubility of recombinant proteins. Then these vector plasmids were transformed into E. coli BL21 (DE3 Chaperone competent cells for amplification. The solubility of these recombinant proteins was determined by SDS-PAGE and Coomassie brilliant blue staining. The recombinant proteins were purified by Ni-NTA resin and identified by Western blot. The transduction of these proteins into HEK 293T cells were evaluated by immunofluorescence staining. RESULTS: These four reprogramming proteins could be produced in soluble format in pCold-SUMO expression vector system with the assistance of chaperone proteins in bacteria. The proteins were purified successfully with a purity of over 70% with a relative high transduction rate into 293 cells. CONCLUSION: The results in the present study indicate the four important reprogramming proteins, cMyc, Klf4, Oct4, and Sox2, can be produced in soluble format in bacteria with low cost. Our new method thus might be expected to greatly contribute to the future study of iPSCs.

  13. Efficacy, pharmacokinetics, tisssue distribution, and metabolism of the Myc-Max disruptor, 10058-F4 [Z,E]-5-[4-ethylbenzylidine]-2-thioxothiazolidin-4-one, in mice.

    Science.gov (United States)

    Guo, Jianxia; Parise, Robert A; Joseph, Erin; Egorin, Merrill J; Lazo, John S; Prochownik, Edward V; Eiseman, Julie L

    2009-03-01

    c-Myc is commonly activated in many human tumors and is functionally important in cellular proliferation, differentiation, apoptosis and cell cycle progression. The activity of c-Myc requires noncovalent interaction with its client protein Max. In vitro studies indicate the thioxothiazolidinone, 10058-F4, inhibits c-Myc/Max dimerization. In this study, we report the efficacy, pharmacokinetics and metabolism of this novel protein-protein disruptor in mice. SCID mice bearing DU145 or PC-3 human prostate cancer xenografts were treated with either 20 or 30 mg/kg 10058-F4 on a qdx5 schedule for 2 weeks for efficacy studies. For pharmacokinetics and metabolism studies, mice bearing PC-3 or DU145 xenografts were treated with 20 mg/kg of 10058-F4 i.v. Plasma and tissues were collected 5-1440 min after dosing. The concentration of 10058-F4 in plasma and tissues was determined by HPLC, and metabolites were characterized by LC-MS/MS. Following a single iv dose, peak plasma 10058-F4 concentrations of approximately 300 muM were seen at 5 min and declined to below the detection limit at 360 min. Plasma concentration versus time data were best approximated by a two-compartment, open, linear model. The highest tissue concentrations of 10058-F4 were found in fat, lung, liver, and kidney. Peak tumor concentrations of 10058-F4 were at least tenfold lower than peak plasma concentrations. Eight metabolites of 10058-F4 were identified in plasma, liver, and kidney. The terminal half-life of 10058-F4 was approximately 1 h, and the volume of distribution was >200 ml/kg. No significant inhibition of tumor growth was seen after i.v. treatment of mice with either 20 or 30 mg/kg 10058-F4. The lack of significant antitumor activity of 10058-F4 in tumor-bearing mice may have resulted from its rapid metabolism and low concentration in tumors.

  14. Characterization of human septic sera induced gene expression modulation in human myocytes

    OpenAIRE

    Hussein, Shaimaa; Michael, Paul; Brabant, Danielle; Omri, Abdelwahab; Narain, Ravin; Passi, Kalpdrum; Ramana, Chilakamarti V.; Parrillo, Joseph E.; Kumar, Anand; Parissenti, Amadeo; Kumar, Aseem

    2009-01-01

    To gain a better understanding of the gene expression changes that occurs during sepsis, we have performed a cDNA microarray study utilizing a tissue culture model that mimics human sepsis. This study utilized an in vitro model of cultured human fetal cardiac myocytes treated with 10% sera from septic patients or 10% sera from healthy volunteers. A 1700 cDNA expression microarray was used to compare the transcription profile from human cardiac myocytes treated with septic sera vs normal sera....

  15. cDREM: inferring dynamic combinatorial gene regulation.

    Science.gov (United States)

    Wise, Aaron; Bar-Joseph, Ziv

    2015-04-01

    Genes are often combinatorially regulated by multiple transcription factors (TFs). Such combinatorial regulation plays an important role in development and facilitates the ability of cells to respond to different stresses. While a number of approaches have utilized sequence and ChIP-based datasets to study combinational regulation, these have often ignored the combinational logic and the dynamics associated with such regulation. Here we present cDREM, a new method for reconstructing dynamic models of combinatorial regulation. cDREM integrates time series gene expression data with (static) protein interaction data. The method is based on a hidden Markov model and utilizes the sparse group Lasso to identify small subsets of combinatorially active TFs, their time of activation, and the logical function they implement. We tested cDREM on yeast and human data sets. Using yeast we show that the predicted combinatorial sets agree with other high throughput genomic datasets and improve upon prior methods developed to infer combinatorial regulation. Applying cDREM to study human response to flu, we were able to identify several combinatorial TF sets, some of which were known to regulate immune response while others represent novel combinations of important TFs.

  16. Radioactive probes for human gene localisation by in situ hybridisation

    International Nuclear Information System (INIS)

    Fennell, S.J.

    1980-07-01

    Radioactive probes of high specific activity have been used for human gene localisation on metaphase chromosome preparations. Human 5S ribosomal RNA was used as a model system, as a probe for the localisation of human 5S ribosomal genes. 125 I-labelled mouse 5S ribosomal RNA was used to study the 5S ribosomal gene content and arrangement in families with translocations on the long arm of chromosome 1 close to or containing the 5S ribosomal RNA locus, by in situ hybridisation to human metaphase chromosomes from peripheral blood cultures. This confirmed the chromosomal assignment of 5S ribosomal genes to 1q 42-43. In situ hybridisation probes were also prepared from recombinant plasmids containing Xenopus laevis oocyte 5S or 28S/18S gene sequences to give [ 3 H]-labelled cRNA and [ 3 H]-labelled nick-translated plasmid DNA. Studies on the kinetics of hybridisation of plasmid probes with and without ribosomal gene sequences questioned the role of plasmid DNA for amplification of signal during gene localisation. Gene localisation was obtained with nick-translated plasmid DNA containing the 28S/18S ribosomal DNA insert after short exposure times, but poor results were obtained using a [ 3 H]-labelled cRNA probe transcribed from the plasmid with the 5S gene insert. (author)

  17. Real-time PCR based on SYBR-Green I fluorescence: An alternative to the TaqMan assay for a relative quantification of gene rearrangements, gene amplifications and micro gene deletions

    Directory of Open Access Journals (Sweden)

    Puisieux Alain

    2003-10-01

    Full Text Available Abstract Background Real-time PCR is increasingly being adopted for RNA quantification and genetic analysis. At present the most popular real-time PCR assay is based on the hybridisation of a dual-labelled probe to the PCR product, and the development of a signal by loss of fluorescence quenching as PCR degrades the probe. Though this so-called 'TaqMan' approach has proved easy to optimise in practice, the dual-labelled probes are relatively expensive. Results We have designed a new assay based on SYBR-Green I binding that is quick, reliable, easily optimised and compares well with the published assay. Here we demonstrate its general applicability by measuring copy number in three different genetic contexts; the quantification of a gene rearrangement (T-cell receptor excision circles (TREC in peripheral blood mononuclear cells; the detection and quantification of GLI, MYC-C and MYC-N gene amplification in cell lines and cancer biopsies; and detection of deletions in the OPA1 gene in dominant optic atrophy. Conclusion Our assay has important clinical applications, providing accurate diagnostic results in less time, from less biopsy material and at less cost than assays currently employed such as FISH or Southern blotting.

  18. Human reporter genes: potential use in clinical studies

    Energy Technology Data Exchange (ETDEWEB)

    Serganova, Inna [Department of Neurology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021 (United States); Ponomarev, Vladimir [Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021 (United States); Blasberg, Ronald [Department of Neurology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021 (United States); Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021 (United States)], E-mail: blasberg@neuro1.mskcc.org

    2007-10-15

    The clinical application of positron-emission-tomography-based reporter gene imaging will expand over the next several years. The translation of reporter gene imaging technology into clinical applications is the focus of this review, with emphasis on the development and use of human reporter genes. Human reporter genes will play an increasingly more important role in this development, and it is likely that one or more reporter systems (human gene and complimentary radiopharmaceutical) will take leading roles. Three classes of human reporter genes are discussed and compared: receptors, transporters and enzymes. Examples of highly expressed cell membrane receptors include specific membrane somatostatin receptors (hSSTrs). The transporter group includes the sodium iodide symporter (hNIS) and the norepinephrine transporter (hNET). The endogenous enzyme classification includes human mitochondrial thymidine kinase 2 (hTK2). In addition, we also discuss the nonhuman dopamine 2 receptor and two viral reporter genes, the wild-type herpes simplex virus 1 thymidine kinase (HSV1-tk) gene and the HSV1-tk mutant (HSV1-sr39tk). Initial applications of reporter gene imaging in patients will be developed within two different clinical disciplines: (a) gene therapy and (b) adoptive cell-based therapies. These studies will benefit from the availability of efficient human reporter systems that can provide critical monitoring information for adenoviral-based, retroviral-based and lenteviral-based gene therapies, oncolytic bacterial and viral therapies, and adoptive cell-based therapies. Translational applications of noninvasive in vivo reporter gene imaging are likely to include: (a) quantitative monitoring of gene therapy vectors for targeting and transduction efficacy in clinical protocols by imaging the location, extent and duration of transgene expression; (b) monitoring of cell trafficking, targeting, replication and activation in adoptive T-cell and stem/progenitor cell therapies

  19. Human reporter genes: potential use in clinical studies

    International Nuclear Information System (INIS)

    Serganova, Inna; Ponomarev, Vladimir; Blasberg, Ronald

    2007-01-01

    The clinical application of positron-emission-tomography-based reporter gene imaging will expand over the next several years. The translation of reporter gene imaging technology into clinical applications is the focus of this review, with emphasis on the development and use of human reporter genes. Human reporter genes will play an increasingly more important role in this development, and it is likely that one or more reporter systems (human gene and complimentary radiopharmaceutical) will take leading roles. Three classes of human reporter genes are discussed and compared: receptors, transporters and enzymes. Examples of highly expressed cell membrane receptors include specific membrane somatostatin receptors (hSSTrs). The transporter group includes the sodium iodide symporter (hNIS) and the norepinephrine transporter (hNET). The endogenous enzyme classification includes human mitochondrial thymidine kinase 2 (hTK2). In addition, we also discuss the nonhuman dopamine 2 receptor and two viral reporter genes, the wild-type herpes simplex virus 1 thymidine kinase (HSV1-tk) gene and the HSV1-tk mutant (HSV1-sr39tk). Initial applications of reporter gene imaging in patients will be developed within two different clinical disciplines: (a) gene therapy and (b) adoptive cell-based therapies. These studies will benefit from the availability of efficient human reporter systems that can provide critical monitoring information for adenoviral-based, retroviral-based and lenteviral-based gene therapies, oncolytic bacterial and viral therapies, and adoptive cell-based therapies. Translational applications of noninvasive in vivo reporter gene imaging are likely to include: (a) quantitative monitoring of gene therapy vectors for targeting and transduction efficacy in clinical protocols by imaging the location, extent and duration of transgene expression; (b) monitoring of cell trafficking, targeting, replication and activation in adoptive T-cell and stem/progenitor cell therapies

  20. Concomitant targeting of multiple key transcription factors effectively disrupts cancer stem cells enriched in side population of human pancreatic cancer cells.

    Directory of Open Access Journals (Sweden)

    Xiyan Wang

    Full Text Available A major challenge in the treatment of pancreatic ductal adenocarcinoma is the failure of chemotherapy, which is likely due to the presence of the cancer stem cells (CSCs.To identify side population (SP cells and characterize s-like properties in human pancreatic cancer cell lines (h-PCCLs and to exploit the efficacy of concomitant targeting of multiple key transcription factors governing the stemness of pancreatic CSCs in suppressing CSC-like phenotypes.Flow cytometry and Hoechst 33342 DNA-binding dye efflux assay were used to sort SP and non-SP (NSP cells from three h-PCCLs: PANC-1, SW1990, and BxPc-3. The self-renewal ability, invasiveness, migration and drug resistance of SP cells were evaluated. Expression of CSC marker genes was analyzed. Tumorigenicity was assessed using a xenograft model in nude mice. Effects of a complex decoy oligonucleotide (cdODN-SCO designed to simultaneously targeting Sox2, Oct4 and c-Myc were assessed.CSCs were enriched in the side proportion (SP cells contained in the h-PCCLs and they possessed aggressive growth, invasion, migration and drug-resistance properties, compared with NSP cells. SP cells overexpressed stem cell markers CD133 and ALDH1, pluripotency maintaining factors Nanog, Sox2 and Oct4, oncogenic transcription factor c-Myc, signaling molecule Notch1, and drug resistant gene ABCG2. Moreover, SP cells consistently demonstrated significantly greater tumorigenicity than NSP cells in xenograft model of nude mice. CdODN-SOC efficiently suppressed all CSC properties and phenotypes, and minimized the tumorigenic capability of the SP cells and the resistance to chemotherapy. By comparison, the negative control failed to do so.The findings indicate that targeting the key genes conferring the stemness of CSCs can efficiently eliminate CSC-like phenotypes, and thus may be considered a new approach for cancer therapy. Specifically, the present study establishes the combination of Sox2/Oct4/c-Myc targeting as a