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Sample records for c-myc ccnd1 gene

  1. Tissue array for Tp53, C-myc, CCND1 gene over-expression in different tumors

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    AIM: To rapidly detect molecular alterations in different malignancies and investigate the possible role of Tp53, C-myc, and CCND1 genes in development of tumors in human organs and their adjacent normal tissues, as well as the possible relation between well- and poorly-differentiated tumors. METHODS: A tissue array consisting of seven different tumors was generated. The tissue array included 120 points of esophagus, 120 points of stomach, 80 points of rectum, 60 points of thyroid gland, 100 points of mammary gland, 80 points ofliver, and 80 points of colon. Expressions of Tp53, C-myc, and CCND1 were determined by RNA in situ hybridization. 3' terminal digoxin-labeled anti-sense single stranded oligonucleotide and locked nucleic acid modifying probe were used.RESULTS: The expression level of Tp53 gene was higher in six different carcinoma tissue samples than in paracancerous tissue samples with the exception in colon carcinoma tissue samples (P < 0.05). The expression level of CCND1 gene was significantly different in different carcinoma tissue samples with the exception in esophagus and colon carcinoma tissue samples. The expression level of C-myc gene was different in esophagus carcinoma tissue samples (x2 = 18.495, P = 0.000), stomach carcinoma tissue samples (x2 = 23.750, P = 0.000), and thyroid gland tissue samples (x2 = 10.999, P = 0.004). The intensity of signals was also different in different carcinoma tissue samples and paracancerous tissue samples.CONCLUSION: Over-expression of the Tp53, CCND1, and C-myc genes appears to play a role in development of human cancer by regulating the expression of mRNA. Tp53, CCND1 and C-myc genes are significantly correlated with the development of different carcinomas.

  2. Discovery and characterization of a novel CCND1/MRCK gene fusion in mantle cell lymphoma

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    Chioniso Patience Masamha

    2016-03-01

    Full Text Available Abstract The t(11;14 translocation resulting in constitutive cyclin D1 expression is an early event in mantle cell lymphoma (MCL transformation. Patients with a highly proliferative phenotype produce cyclin D1 transcripts with truncated 3′UTRs that evade miRNA regulation. Here, we report the recurrence of a novel gene fusion in MCL cell lines and MCL patient isolates that consists of the full protein coding region of cyclin D1 (CCND1 and a 3′UTR consisting of sequences from both the CCND1 3′UTR and myotonic dystrophy kinase-related Cdc42-binding kinase's (MRCK intron one. The resulting CCND1/MRCK mRNA is resistant to CCND1-targeted miRNA regulation, and targeting the MRCK region of the chimeric 3′UTR with siRNA results in decreased CCND1 levels.

  3. Global regulation of nucleotide biosynthetic genes by c-Myc.

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    Yen-Chun Liu

    Full Text Available BACKGROUND: The c-Myc transcription factor is a master regulator and integrates cell proliferation, cell growth and metabolism through activating thousands of target genes. Our identification of direct c-Myc target genes by chromatin immunoprecipitation (ChIP coupled with pair-end ditag sequencing analysis (ChIP-PET revealed that nucleotide metabolic genes are enriched among c-Myc targets, but the role of Myc in regulating nucleotide metabolic genes has not been comprehensively delineated. METHODOLOGY/PRINCIPAL FINDINGS: Here, we report that the majority of genes in human purine and pyrimidine biosynthesis pathway were induced and directly bound by c-Myc in the P493-6 human Burkitt's lymphoma model cell line. The majority of these genes were also responsive to the ligand-activated Myc-estrogen receptor fusion protein, Myc-ER, in a Myc null rat fibroblast cell line, HO.15 MYC-ER. Furthermore, these targets are also responsive to Myc activation in transgenic mouse livers in vivo. To determine the functional significance of c-Myc regulation of nucleotide metabolism, we sought to determine the effect of loss of function of direct Myc targets inosine monophosphate dehydrogenases (IMPDH1 and IMPDH2 on c-Myc-induced cell growth and proliferation. In this regard, we used a specific IMPDH inhibitor mycophenolic acid (MPA and found that MPA dramatically inhibits c-Myc-induced P493-6 cell proliferation through S-phase arrest and apoptosis. CONCLUSIONS/SIGNIFICANCE: Taken together, these results demonstrate the direct induction of nucleotide metabolic genes by c-Myc in multiple systems. Our finding of an S-phase arrest in cells with diminished IMPDH activity suggests that nucleotide pool balance is essential for c-Myc's orchestration of DNA replication, such that uncoupling of these two processes create DNA replication stress and apoptosis.

  4. Dose-dependent regulation of target gene expression and cell proliferation by c-Myc levels.

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    Schuhmacher, Marino; Eick, Dirk

    2013-01-01

    The proto-oncogene c-myc encodes a basic helix-loop-helix leucine zipper transcription factor (c-Myc). c-Myc plays a crucial role in cell growth and proliferation. Here, we examined how expression of c-Myc target genes and cell proliferation depend on variation of c-Myc protein levels. We show that proliferation rates, the number of cells in S-phase, and cell size increased in a dose-dependent manner in response to increasing c-Myc levels. Likewise, the mRNA levels of c-Myc responsive genes steadily increased with rising c-Myc levels. Strikingly, steady-state mRNA levels of c-Myc target genes did not saturate even at highest c-Myc concentrations. These characteristics predestine c-Myc levels as a cellular rheostat for the control and fine-tuning of cell proliferation and growth rates.

  5. Alteraciones del gen c-Myc en la oncogénesis = c-Myc gene alterations in oncogenesis

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    Ospina Pérez, Mariano

    2011-12-01

    Full Text Available La familia de protooncogenes MYC (c-Myc, N-Myc y L-Myc se relaciona con el origen de diversas neoplasias en seres humanos. Estos genes actúan como factores de transcripción y participan en la regulación del ciclo celular, la proliferación y diferenciación celulares, la apoptosis y la inmortalización. Los genes MYC se expresan en diferentes tejidos y responden a diversas señales internas y externas; codifican para la síntesis de factores de transcripción que se unen al ADN para regular la expresión de múltiples genes. El gen más ampliamente estudiado de esta familia es c-Myc, que se expresa en las células con mayor tasa de proli­feración. C-Myc se encuentra alterado en un gran número de tumores sólidos, leucemias y linfomas. Las alteraciones de c-Myc encontradas con mayor frecuencia en células cancero­sas son las amplificaciones, translocaciones, mutaciones y reordenamientos cromosómicos que involucran el locus de este gen y conducen a que se desregule su expresión en diversas neoplasias humanas. La amplificación de c-Myc es una alteración común en los cánceres de mama, pulmón, ovario y próstata, así como en leucemias y linfomas, mientras que la pérdida de su regulación es común en el cáncer de colon, en tumores ginecológicos y melanoma. En neoplasias con defectos de c-Myc los estudios actuales están dirigidos al desarrollo de nuevas estrategias terapéuticas.

  6. Aluminum oxide nanoparticles alter cell cycle progression through CCND1 and EGR1 gene expression in human mesenchymal stem cells.

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    Periasamy, Vaiyapuri Subbarayan; Athinarayanan, Jegan; Alshatwi, Ali A

    2016-05-01

    Aluminum oxide nanoparticles (Al2 O3 -NPs) are important ceramic materials that have been used in a variety of commercial and industrial applications. However, the impact of acute and chronic exposure to Al2 O3 -NPs on the environment and on human health has not been well studied. In this investigation, we evaluated the cytotoxic effects of Al2 O3 -NPs on human mesenchymal stem cells (hMSCs) by using a cell viability assay and observing cellular morphological changes, analyzing cell cycle progression, and monitoring the expression of cell cycle response genes (PCNA, EGR1, E2F1, CCND1, CCNC, CCNG1, and CYCD3). The Al2 O3 -NPs reduced hMSC viability in a dose- and time-dependent manner. Nuclear condensation and fragmentation, chromosomal DNA fragmentation, and cytoplasmic vacuolization were observed in Al2 O3 -NP-exposed cells. The nuclear morphological changes indicated that Al2 O3 -NPs alter cell cycle progression and gene expression. The cell cycle distribution revealed that Al2 O3 -NPs cause cell cycle arrest in the sub-G0-G1 phase, and this is associated with a reduction in the cell population in the G2/M and G0/G1 phases. Moreover, Al2 O3 -NPs induced the upregulation of cell cycle response genes, including EGR1, E2F1, and CCND1. Our results suggested that exposure to Al2 O3 -NPs could cause acute cytotoxic effects in hMSCs through cell cycle regulatory genes.

  7. c-Myc directly regulates the transcription of the NBS1 gene involved in DNA double-strand break repair.

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    Chiang, Yu-Chi; Teng, Shu-Chun; Su, Yi-Ning; Hsieh, Fon-Jou; Wu, Kou-Juey

    2003-05-23

    The c-myc proto-oncogene encodes a ubiquitous transcription factor involved in the control of cell growth and implicated in inducing tumorigenesis. Understanding the function of c-Myc and its role in cancer depends upon the identification of c-Myc target genes. Nijmegen breakage syndrome (NBS) is a chromosomal-instability syndrome associated with cancer predisposition, radiosensitivity, and chromosomal instability. The NBS gene product, NBS1 (p95 or nibrin), is a part of the hMre11 complex, a central player associated with double-strand break (DSB) repair. NBS1 contains domains characteristic for proteins involved in DNA repair, recombination, and replication. Here we show that c-Myc directly activates NBS1. c-Myc-mediated induction of NBS1 gene transcription occurs in different tissues, is independent of cell proliferation, and is mediated by a c-Myc binding site in the intron 1 region of NBS1 gene. Overexpression of NBS1 in Rat1a cells increased cell proliferation. These results indicate that NBS1 is a direct transcriptional target of c-Myc and links the function of c-Myc to the regulation of DNA DSB repair pathway operating during DNA replication.

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

    Indian Academy of Sciences (India)

    SAMIRA SADEGHI; ZOHREH HOJATI; HOSSEIN TABATABAEIAN

    2017-03-01

    The overexpression of epithelial cell adhesion molecule (EpCAM), a proto-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. However, cooverexpression of EpCAM and c-mycgenes has not been investigated in breast cancer tissues, particularly in Iranian population. The aim of this study was to assess the expression of EpCAM and c-myc genes in malignant breast cancer tissues using reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) followed by analyses of the association between the outcomes. In this study, 122 fresh tissues, including 104 malignant and 18 benign samples, were disrupted by mortar and pestle, and then the RNA was isolated from the samples and converted to cDNA. The relative expression levels of EpCAM and c-myc genes were measured by2−ΔΔCt method using RT-qPCR. EpCAM protein level was also assessed in 66 cases using Western blot technique. UsingRT-qPCR method, our results showed that EpCAM was overexpressed in 48% of malignant and 11.1% of benign samples. Evaluating EpCAM protein overexpression in a portion of samples depicted the fully concordance rate between Western blot and RT-qPCR techniques. C-myc expression was first evaluated by RT-qPCR method, showing the overexpression rate of 39%and 28% in malignant and benign samples, respectively. These data were also quite concordant with the clinically available immunohistochemistry reports of the same samples studied in this study. Importantly, overexpression of EpCAM and c-myc was significantly associated and showed an agreement of 57.3%. This study demonstrated the cooverexpression of EpCAM and c-myc in breast tumours collected from breast cancer patients of the Iranian population. EpCAM and c-myc positive cases were significantly associated with reduced and enhanced risk of ER/PR positivity

  9. Alterations of c-Myc and c-erbB-2 genes in ovarian tumours

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    Pastor Tibor

    2009-01-01

    Full Text Available Introduction. According to clinical and epidemiological studies, ovarian cancer ranks fifth in cancer deaths among women. The causes of ovarian cancer remain largely unknown but various factors may increase the risk of developing it, such as age, family history of cancer, childbearing status etc. This cancer results from a succession of genetic alterations involving oncogenes and tumour suppressor genes, which have a critical role in normal cell growth regulation. Mutations and/or overexpression of three oncogenes, c-erbB-2, c-Myc and K-ras, and of the tumour suppressor gene p53, have been frequently observed in a sporadic ovarian cancer. Objective. The aim of the present study was to analyze c-Myc and c-erbB-2 oncogene alterations, specifically amplification, as one of main mechanisms of their activation in ovarian cancers and to establish a possible association with the pathogenic process. Methods. DNA was isolated from 15 samples of malignant and 5 benign ovarian tumours, using proteinase K digestion, followed by phenol-chloroform isoamyl extraction and ethanol precipitation. C-Myc and c-erbB-2 amplification were detected by differential PCR. The level of gene copy increase was measured using the Scion image software. Results. The amplification of both c-Myc and c-erbB-2 was detected in 26.7% of ovarian epithelial carcinoma specimens. Only one tumour specimen concomitantly showed increased gene copy number for both studied genes. Interestingly, besides amplification, gene deletion was also detected (26.7% for c-erbB-2. Most of the ovarian carcinomas with alterations in c-Myc and c-erbB-2 belonged to advanced FIGO stages. Conclusion. The amplification of c-Myc and c-erbB-2 oncogenes in ovarian epithelial carcinomas is most probably a late event in the pathogenesis conferring these tumours a more aggressive biological behaviour. Similarly, gene deletions point to genomic instability in epithelial carcinomas in higher clinical stages as the

  10. Deciphering c-MYC-regulated genes in two distinct tissues

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    Hunter Ewan

    2011-09-01

    Full Text Available Abstract Background The transcription factor MYC is a critical regulator of diverse cellular processes, including both replication and apoptosis. Differences in MYC-regulated gene expression responsible for such opposing outcomes in vivo remain obscure. To address this we have examined time-dependent changes in global gene expression in two transgenic mouse models in which MYC activation, in either skin suprabasal keratinocytes or pancreatic islet β-cells, promotes tissue expansion or involution, respectively. Results Consistent with observed phenotypes, expression of cell cycle genes is increased in both models (albeit enriched in β-cells, as are those involved in cell growth and metabolism, while expression of genes involved in cell differentiation is down-regulated. However, in β-cells, which unlike suprabasal keratinocytes undergo prominent apoptosis from 24 hours, there is up-regulation of genes associated with DNA-damage response and intrinsic apoptotic pathways, including Atr, Arf, Bax and Cycs. In striking contrast, this is not the case for suprabasal keratinocytes, where pro-apoptotic genes such as Noxa are down-regulated and key anti-apoptotic pathways (such as Igf1-Akt and those promoting angiogenesis are up-regulated. Moreover, dramatic up-regulation of steroid hormone-regulated Kallikrein serine protease family members in suprabasal keratinocytes alone could further enhance local Igf1 actions, such as through proteolysis of Igf1 binding proteins. Conclusions Activation of MYC causes cell growth, loss of differentiation and cell cycle entry in both β-cells and suprabasal keratinocytes in vivo. Apoptosis, which is confined to β-cells, may involve a combination of a DNA-damage response and downstream activation of pro-apoptotic signalling pathways, including Cdc2a and p19Arf/p53, and downstream targets. Conversely, avoidance of apoptosis in suprabasal keratinocytes may result primarily from the activation of key anti

  11. Absence of missense mutations in activated c-myc genes in avian leukosis virus-induced B-cell lymphomas

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    Hahn, M.; Hayward, W.S.

    1988-06-01

    The authors determined the nucleotide sequences of two independent DNA clones which contained the activated c-myc genes from avian leukosis virus-induced B-cell lymphomas. Neither of these c-myce genes contained missense mutations. This strongly supports the notion that the c-myc photo-oncogene in avian leukosis virus-induced B-cell lymphomas can be oncogenically activated by altered expression of the gene without a change in the primary structure of the gene product.

  12. Thermal injuries induce gene expression of endogenous c-fos, c-myc and bFGF in burned tissues

    Institute of Scientific and Technical Information of China (English)

    付小兵; 顾小曼; 孙同柱; 杨银辉; 孙晓庆; 盛志勇

    2003-01-01

    Objective To investigate the expression sequence and distribution characteristics of the protooncogenes c-fos, c-myc and endogenous basic fibroblast growth factor (bFGF ) genes in burned tissues, and to explore the possible effects of changes in the se genes' functions on wound healing. Methods Partial-thickness burns of 30% TBSA were established on backs of Wistar rats. Insitu hybridization and histological methods were used to detect expression of c-fos, c-myc and bFGF genes in normal and burned tissue at 3 h, 6 h, 1 d, 3 d , 7 d and 14 d postburn. Results Although expression of c-fos and c-myc genes and bFGF gene could be found in normal skin, the expression of all three were markedly induced by burn wounds and the expression models in sequence and distribution were quite different. Expre ssion of c-fos gene increased and peaked at 6 h. Signals were mainly localiz ed in both nuclei of dermal fibroblasts and monocytes. The expression of bFGF gene increased at 6 h and peaked at 1 d postburn, and was distributed in the cyt oplasm of fibroblasts. C-myc gene peaked 3 d postburn and was also distributed in the cytoplasm of fibroblasts. Conclusions These results indicated that thermal injury could induce the expression of c-fos, c-myc and bFGF at gene level, showing phasic control and regional distributi on. The phasic expression of these genes suggests that there is an interaction between protooncogenes and bFGF, which may play an important role in wound heali ng. The different expressions of c-fos and c-myc play an inducing role in reg ulating bFGF, and in turn affect wound healing.

  13. Perturbation of 14q32 miRNAs-cMYC gene network in osteosarcoma.

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    Thayanithy, Venugopal; Sarver, Aaron L; Kartha, Reena V; Li, Lihua; Angstadt, Andrea Y; Breen, Matthew; Steer, Clifford J; Modiano, Jaime F; Subramanian, Subbaya

    2012-01-01

    Osteosarcoma (OS) is the common histological form of primary bone cancer and one of the leading aggressive cancers in children under age fifteen. Although several genetic predisposing conditions have been associated with OS the understanding of its molecular etiology is limited. Here, we show that microRNAs (miRNAs) at the chr.14q32 locus are significantly downregulated in osteosarcoma compared to normal bone tissues. Bioinformatic predictions identified that a subset of 14q32 miRNAs (miR-382, miR-369-3p, miR-544 and miR-134) could potentially target cMYC transcript. The physical interaction between these 14q32 miRNAs and cMYC was validated using reporter assays. Further, restoring expression of these four 14q32 miRNAs decreased cMYC levels and induced apoptosis in Saos2 cells. We also show that exogenous expression of 14q32 miRNAs in Saos2 cells significantly downregulated miR-17-92, a transcriptional target of cMYC. The pro-apoptotic effect of 14q32 miRNAs in Saos2 cells was rescued either by overexpression of cMYC cDNA without the 3'UTR or with miR-17-92 cluster. Further, array comparative genomic hybridization studies showed no DNA copy number changes at 14q32 locus in OS patient samples suggesting that downregulation of 14q32 miRNAs are not due to deletion at this locus. Together, our data support a model where the deregulation of a network involving 14q32 miRNAs, cMYC and miR-17-92 miRNAs could contribute to osteosarcoma pathogenesis.

  14. Targeting c-Myc-activated genes with a correlation method: Detection of global changes in large gene expression network dynamics

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    Remondini, D.; O'Connell, B.; Intrator, N.; Sedivy, J. M.; Neretti, N.; Castellani, G. C.; Cooper, L. N.

    2005-01-01

    This work studies the dynamics of a gene expression time series network. The network, which is obtained from the correlation of gene expressions, exhibits global dynamic properties that emerge after a cell state perturbation. The main features of this network appear to be more robust when compared with those obtained with a network obtained from a linear Markov model. In particular, the network properties strongly depend on the exact time sequence relationships between genes and are destroyed by random temporal data shuffling. We discuss in detail the problem of finding targets of the c-myc protooncogene, which encodes a transcriptional regulator whose inappropriate expression has been correlated with a wide array of malignancies. The data used for network construction are a time series of gene expression, collected by microarray analysis of a rat fibroblast cell line expressing a conditional Myc-estrogen receptor oncoprotein. We show that the correlation-based model can establish a clear relationship between network structure and the cascade of c-myc-activated genes. PMID:15867157

  15. Proliferation and C-myc Gene Expression of Smooth Muscle Cells in Rabbit Carotid Artery after Stenting

    Institute of Scientific and Technical Information of China (English)

    张新霞; 崔长琮; 胡雪松; 魏文斌; 李松; 许香广

    2004-01-01

    Objectives To investigate the proliferation of smooth muscle cells (VSMCs) and the expression of c-myc gene in rabbit carotid arteries after stenting. Methods Platinium-Iridium stent were implanted into the right carotid arteries of 16 rabbits under vision. 7,14,30 and 90 days after the stenting procedure, morphological changes of VSMCs were observed under light and transmission electron microscope. The c-myc gene expression was detected by in situ hybridization (ISH) and immunohistochemical staining. Results 7 days after stenting, the phenotype of VSMCs changed from contractile to synthetic phenotype; there were a number of proliferative VSMCs in the neointima. At 14 and 30 days, there were synthetic and transitive VSMCs. At 90 days, the phenotype of VSMCs recovered to contractile phenotype.The ultrastructure of typical synthetic phenotype of VSMCs were round, containing a large amount of rough endoplasmic reticulum and mitochondria. Cmyc expression were positive both by ISH and immunohistochemical staining. Conclusions C-myc gene expression increases and closely relates to VSMCs proliferation after stenting. It may play an important role in the in-stent restenosis.

  16. The Influence of Nano-apatite on c-myc and p53 Gene in the Hepatocellular Carcinoma

    Institute of Scientific and Technical Information of China (English)

    CHEN Jun; CAO Xianying; LI Shipu; HAN Yingchao; ZHANG Ran

    2005-01-01

    The influence mechanism of the nano-apatite on the human hepatocellular carcinoma in vitro was investigated. Using the homogeneous precipitation method, the nano-apatite was synthesized at room temperature, and it was characterized with transmission electron microscopy (TEM) and the Zataplus. The influence on the expression of the c-myc and p53 gene in the human hepatocellular carcinoma cell lines were tested with the TEM and hybridization in situ. The TEM and the Zataplus analyses show that the nano-apatite is distributed homogenously in size and needle-shaped sizes, which ranges from 67.5 nm to 88.3 nm. It is found that the nano-apatitet increases the volume of the human hepatocellular carcinoma cells, makes extensive cytoplasmic vacuolization, the mitochondria swelling, chromatin in nucleus dispersed partially and condensed around the nuclear membranes.The interspace in nuclear membranes were separated and even the cytoplasm dissolved. It is also found that the expression of the c-myc gene is inhibited, but the p53 is enhanced. The experimental results demonstrate that the nano-apatite enables the oncosis of the human hepatocellular carcinoma cells by down-regulation of the expression of the c-myc and up-regulation of the expression of the p53 in vitro.

  17. Expression of p53 and C-myc genes and its clinical relevance in the hepatocellular carcinomatous and pericarcinomatous tissues

    Institute of Scientific and Technical Information of China (English)

    Zhao-Shan Niu; Bo-Kian Li; Mei Wang

    2002-01-01

    AIM: To investigate the possible roles of p53 and C-mycgenes in the primary hepatocellular carcinogenesis and therelationship between the liver hyperplastic nodule(LHN) andhepatocellular carcinoma(HCC).METHODS: The expression of p53 and C-myc genes wasdetected immunohist-ochemically in 73 and 60 cases of HCCand pericarcinomatous tissues, respectively .RESULTS: The positive expression of p53 in HCC wassignificantly higher than that in pericarcinomatous tissues(P<0.05). In pericarcinomatous tissues, the p53 expressionwas observed only in LHN, but not in liver cirrhosis (LC) andnormal liver tissues. The positive expression rate of C-mycin HCC or LHN was significantly higher than that in LC ornormal liver tissues (P<0.05 and P<0.01), however, nosignificant difference was found between HCC and LHN(P>0.05). The positive expression rate of p53 and C-myc inHCC was correlated with the histological differentiation, thatin the poorly differentiated was significantly higher than thatin well differentiated samples (P<0.05).CONCLUSION: The overexpression of p53 and C-myc genesmight play a role in the carcinogenesis of HCC; And LHNseems a preneoplastic lesion related to hepatocarcinogenesis;No evidence supports that LC contribute directly to thehepatocarcinogenesis.

  18. Decoding c-Myc networks of cell cycle and apoptosis regulated genes in a transgenic mouse model of papillary lung adenocarcinomas.

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    Ciribilli, Yari; Singh, Prashant; Spanel, Reinhard; Inga, Alberto; Borlak, Jürgen

    2015-10-13

    The c-Myc gene codes for a basic-helix-loop-helix-leucine zipper transcription factor protein and is reported to be frequently over-expressed in human cancers. Given that c-Myc plays an essential role in neoplastic transformation we wished to define its activity in lung cancer and therefore studied its targeted expression to respiratory epithelium in a transgenic mouse disease model. Using histological well-defined tumors, transcriptome analysis identified novel c-Myc responsive cell cycle and apoptosis genes that were validated as direct c-Myc targets using EMSA, Western blotting, gene reporter and ChIP assays.Through computational analyses c-Myc cooperating transcription factors emerged for repressed and up-regulated genes in cancer samples, namely Klf7, Gata3, Sox18, p53 and Elf5 and Cebpα, respectively. Conversely, at promoters of genes regulated in transgenic but non-carcinomatous lung tissue enriched binding sites for c-Myc, Hbp1, Hif1 were observed. Bioinformatic analysis of tumor transcriptomic data revealed regulatory gene networks and highlighted mortalin and moesin as master regulators while gene reporter and ChIP assays in the H1299 lung cancer cell line as well as cross-examination of published ChIP-sequence data of 7 human and 2 mouse cell lines provided strong evidence for the identified genes to be c-Myc targets. The clinical significance of findings was established by evaluating expression of orthologous proteins in human lung cancer. Taken collectively, a molecular circuit for c-Myc-dependent cellular transformation was identified and the network analysis broadened the perspective for molecularly targeted therapies.

  19. 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.

  20. Cloned origin of DNA replication in c-myc gene can function and be transmitted in transgenic mice in an episomal state.

    OpenAIRE

    Sudo, Katsuko; Ogata, Masaaki; Sato, Yoshinari; Iguchi-Ariga, Sanae M. M.; Ariga, Hiroyoshi

    1990-01-01

    The c-myc protein has recently been shown to interact with a region possessing putative origin of DNA replication and enhancer activities located 2 kb upstream of the c-myc gene itself. Transgenic mice were obtained by injecting constructs containing this region, termed pmyc(H-P), into fertilized mouse eggs. The transgenic elements were capable of efficient replication in all mouse tissues examined and were maintained in an episomal state even in highly differentiated cells. Moreover, pmyc(H-...

  1. BRCA1 and c-Myc associate to transcriptionally repress psoriasin, a DNA damage-inducible gene.

    Science.gov (United States)

    Kennedy, Richard D; Gorski, Julia J; Quinn, Jennifer E; Stewart, Gail E; James, Colin R; Moore, Stephen; Mulligan, Karl; Emberley, Ethan D; Lioe, Tong F; Morrison, Patrick J; Mullan, Paul B; Reid, George; Johnston, Patrick G; Watson, Peter H; Harkin, D Paul

    2005-11-15

    Evidence is accumulating to suggest that some of the diverse functions associated with BRCA1 may relate to its ability to transcriptionally regulate key downstream target genes. Here, we identify S100A7 (psoriasin), S100A8, and S100A9, members of the S100A family of calcium-binding proteins, as novel BRCA1-repressed targets. We show that functional BRCA1 is required for repression of these family members and that a BRCA1 disease-associated mutation abrogates BRCA1-mediated repression of psoriasin. Furthermore, we show that BRCA1 and c-Myc form a complex on the psoriasin promoter and that BRCA1-mediated repression of psoriasin is dependent on functional c-Myc. Finally, we show that psoriasin expression is induced by the topoisomerase IIalpha poison, etoposide, in the absence of functional BRCA1 and increased psoriasin expression enhances cellular sensitivity to this chemotherapeutic agent. Therefore, we identified a novel transcriptional mechanism that is likely to contribute to BRCA1-mediated resistance to etoposide.

  2. Expression of telomerase hTERT in human non-small cell lung cancer and its correlation with c-myc gene

    Institute of Scientific and Technical Information of China (English)

    耿志华; 张敦华; 刘银坤

    2003-01-01

    Objective To investigate the expression of human telomerase catalytic subunit, hTERT, in human non-small cell lung cancer (NSCLC) and its correlations to c-myc gene.Methods hTERT and c-myc mRNA expressions were detected by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). Statistical correlation analysis was made to estimate whether there was interrelation between them.Results Positive rate of hTERT expression in 51 surgically resected lung cancer specimens was 86.3%, significantly higher than that in adjacent non-neoplastic lung tissues and benign lesions, which were 14.3% and 27.3% respectively. No statistical significance was observed between the frequency of hTERT expression and histologic types, degree of differentiation, TNM stages, tumor size or lymph nodes metastases. Correlation analysis revealed that the expression of c-myc gene was significantly related to that of hTERT (correlation coefficient, r=0.633, P<0.001).Conclusions hTERT may be a useful tumor marker in diagnosing lung cancer. Significant correlation between the expression of hTERT and c-myc mRNA indicates that the activation and up-regulation of hTERT might be conferred by over-expression of c-myc gene.

  3. Identification of functional networks of estrogen- and c-Myc-responsive genes and their relationship to response to tamoxifen therapy in breast cancer.

    Directory of Open Access Journals (Sweden)

    Elizabeth A Musgrove

    Full Text Available BACKGROUND: Estrogen is a pivotal regulator of cell proliferation in the normal breast and breast cancer. Endocrine therapies targeting the estrogen receptor are effective in breast cancer, but their success is limited by intrinsic and acquired resistance. METHODOLOGY/PRINCIPAL FINDINGS: With the goal of gaining mechanistic insights into estrogen action and endocrine resistance, we classified estrogen-regulated genes by function, and determined the relationship between functionally-related genesets and the response to tamoxifen in breast cancer patients. Estrogen-responsive genes were identified by transcript profiling of MCF-7 breast cancer cells. Pathway analysis based on functional annotation of these estrogen-regulated genes identified gene signatures with known or predicted roles in cell cycle control, cell growth (i.e. ribosome biogenesis and protein synthesis, cell death/survival signaling and transcriptional regulation. Since inducible expression of c-Myc in antiestrogen-arrested cells can recapitulate many of the effects of estrogen on molecular endpoints related to cell cycle progression, the estrogen-regulated genes that were also targets of c-Myc were identified using cells inducibly expressing c-Myc. Selected genes classified as estrogen and c-Myc targets displayed similar levels of regulation by estrogen and c-Myc and were not estrogen-regulated in the presence of siMyc. Genes regulated by c-Myc accounted for 50% of all acutely estrogen-regulated genes but comprised 85% (110/129 genes in the cell growth signature. siRNA-mediated inhibition of c-Myc induction impaired estrogen regulation of ribosome biogenesis and protein synthesis, consistent with the prediction that estrogen regulates cell growth principally via c-Myc. The 'cell cycle', 'cell growth' and 'cell death' gene signatures each identified patients with an attenuated response in a cohort of 246 tamoxifen-treated patients. In multivariate analysis the cell death signature

  4. Long-term cultivation of in vitro Apis mellifera cells by gene transfer of human c-myc proto-oncogene.

    Science.gov (United States)

    Kitagishi, Yasuko; Okumura, Naoko; Yoshida, Hitomi; Nishimura, Yuri; Takahashi, Jun-ichi; Matsuda, Satoru

    2011-08-01

    Establishment of cell lines representative of honeybee character would greatly assist in their analysis. Here, we show that immortalized cell line, designated as MYN9, has been generated from honeybee embryo by the gene transfer of human c-myc proto-oncogene. The morphology of the cell is characteristic of embryonic stem cell, although the cell is stable and does not spontaneously differentiate. Polymerase chain reaction analyses show that the cell is originated from authentic honeybee cell. It is proposed that the integration of human c-myc gene into honeybee precursor populations results in the establishment of stable cell line suitable for cellular and molecular studies.

  5. Targeted deletion of multiple CTCF-binding elements in the human C-MYC gene reveals a requirement for CTCF in C-MYC expression.

    Directory of Open Access Journals (Sweden)

    Wendy M Gombert

    Full Text Available BACKGROUND: Insulators and domain boundaries both shield genes from adjacent enhancers and inhibit intrusion of heterochromatin into transgenes. Previous studies examined the functional mechanism of the MYC insulator element MINE and its CTCF binding sites in the context of transgenes that were randomly inserted into the genome by transfection. However, the contribution of CTCF binding sites to both gene regulation and maintenance of chromatin has not been tested at the endogenous MYC gene. METHODOLOGY/PRINCIPAL FINDINGS: To determine the impact of CTCF binding on MYC expression, a series of mutant human chromosomal alleles was prepared in homologous recombination-efficient DT40 cells and individually transferred by microcell fusion into murine cells. Functional tests reported here reveal that deletion of CTCF binding elements within the MINE does not impact the capacity of this locus to correctly organize an 'accessible' open chromatin domain, suggesting that these sites are not essential for the formation of a competent, transcriptionally active locus. Moreover, deletion of the CTCF site at the MYC P2 promoter reduces transcription but does not affect promoter acetylation or serum-inducible transcription. Importantly, removal of either CTCF site leads to DNA methylation of flanking sequences, thereby contributing to progressive loss of transcriptional activity. CONCLUSIONS: These findings collectively demonstrate that CTCF-binding at the human MYC locus does not repress transcriptional activity but is required for protection from DNA methylation.

  6. c-myc null cells misregulate cad and gadd45 but not other proposed c-Myc targets

    Science.gov (United States)

    Bush, Andrew; Mateyak, Maria; Dugan, Kerri; Obaya, Alvaro; Adachi, Susumu; Sedivy, John; Cole, Michael

    1998-01-01

    We report here that the expression of virtually all proposed c-Myc target genes is unchanged in cells containing a homozygous null deletion of c-myc. Two noteworthy exceptions are the gene cad, which has reduced log phase expression and serum induction in c-myc null cells, and the growth arrest gene gadd45, which is derepressed by c-myc knockout. Thus, cad and gadd45 are the only proposed targets of c-Myc that may contribute to the dramatic slow growth phenotype of c-myc null cells. Our results demonstrate that a loss-of-function approach is critical for the evaluation of potential c-Myc target genes. PMID:9869632

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

    Directory of Open Access Journals (Sweden)

    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.

  8. INCREASED EXPRESSION OF PDGF AND C-MYC GENES IN LUNGS AND PULMONARY ARTERIES OF PULMONARY HYPERTENSIVE RATS INDUCED BY HYPOXIA

    Institute of Scientific and Technical Information of China (English)

    蔡英年; 韩梅; 罗兰; 宋为; 周晓梅

    1996-01-01

    The role of growth factors and proto-oncogene in pulmonary vascular structural remodelling is not well known.The present study examined gene expression of plateler-derived growth factor(PDGF)-A and -B chain and proto-oncogene,c-myc,in lung tissue and pulmonary artery of rats exposed to hypoxia and compred to those levels of gene expression in normal rats.Normal lungs and pulmonary artery expressed PDGF-A chain transcripr of 1.7kb and PDGF-B chain transcript of 3.5 Kb. The c-myc transcript of 2.2 kb was expressed as well.After hypoxic exposure for 7 and 14 days mRNA levels of PDGF-B chain and c-myc were elevated significantly compared with those of control rats.PDGF-A chain mRNA increased after hypoxia for 7 days,and then declined.These results suggest that activation of sutocrine and /or paracrine is important in proliferation mechanism of pulmonary artery smooth muscle cells in bypoxic pulmonary hypertensive rats.

  9. Functional analysis of Burkitt's lymphoma mutant c-Myc proteins

    OpenAIRE

    1996-01-01

    The c-myc gene encodes a sequence-specific DNA binding protein that activates transcription of cellular genes. Transcription activation by Myc proteins is regulated by phosphorylation of serine and threonine residues within the transactivation domain and by complex formation with the retinoblastoma-related protein p107. In Burkitt’s lymphoma, missense mutations within the c-Myc transactivation domain have been found with high frequency. It has been reported that mutant c-Myc proteins derived ...

  10. DJ-1, an oncogene and causative gene for familial Parkinson's disease, is essential for SV40 transformation in mouse fibroblasts through up-regulation of c-Myc

    OpenAIRE

    Kim, Yun Chul; Kitaura, Hirotake; Iguchi-Ariga, Sanae M. M.; Ariga, Hiroyoshi

    2010-01-01

    Simian virus 40 (SV40) is a tumor virus and its early gene product large T-antigen (LT) is responsible for the transforming activity of SV40. Parkinson's disease causative gene DJ-1 is also a ras-dependent oncogene, but the mechanism of its oncogene function is still not known. In this study, we found that there were no transformed foci when fibroblasts from DJ-1-knockout mice were transfected with LT. We also found that DJ-1 directly bound to LT and that the expression level of c-Myc in tran...

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. ALK and c-myc gene of anaplastic large cell lymphoma%间变性大细胞淋巴瘤的ALK和c-myc基因研究

    Institute of Scientific and Technical Information of China (English)

    于冉; 周春菊; 陈刚; 高子芬; 时云飞; 石岩; 谢建兰; 周小鸽; 宫丽平

    2010-01-01

    目的 探讨间变性大细胞淋巴瘤(ALCL)中间变性淋巴瘤激酶(ALK)基因与c-myc基因的分子遗传学改变.方法 收集原发系统性ALCL石蜡包埋组织标本72例,利用间期荧光原位杂交(FISH)技术检测ALCL肿瘤组织中ALK和c-myc基因结构与数目的变化.结果 72例ALCL中,ALK阳性者42例,40例存在涉及ALK基因的染色体易位,其中17例同时伴有ALK基因的多拷贝;ALK阴性的30例均未发现ALK基因的易位,但其中14例存在ALK基因的多拷贝.ALK基因多拷贝的发生率在ALK阳性与阴性组中的差异无统计学意义(P>0.05).72例病例中,均未发现涉及c-myc基因的染色体易位,但其中24例存在c-myc基因的多拷贝.结论 大部分ALCL伴有ALK基因的异常(75.0%).以涉及ALK基因的染色体易位最为多见(55.6%),ALK基因多拷贝也是ALCL较为常见的遗传学改变(43.1%).前者只出现于ALK阳性ALCL中,后者既可出现在ALK阳性也可出现在ALK阴性的ALCL中.ALCL中不见或罕见涉及c-myc基因的染色体易位,但c-myc基因多拷贝的现象较为常见(33.3%).%Objective To investigate the molecular genetic changes of anaplastic lymphoma kinase (ALK) gene and c-myc gene in anaplastic large cell lymphoma (ALCL). Methods The structural aberrations and changes of copy numbers in ALK and c-myc genes in 72 paraffin-embedded ALCL specimens were detected by interphase fluorescence in situ hybridization (FISH). Results Among 72 ALCL specimens, ALK protein was expressed in 42, ALK gene translocation was detected in 40 specimens in which extra copies of ALK gene were detected in 17. ALK gene translocation was not found in all 30 ALK negative specimens, but extra copies of ALK gene were detected in 14 cases. The difference of incidence rates of extra copies in ALK gene between ALK positive and ALK negative specimens was not significant (P>0.05). c-myc gene translocation was not found in any of 72 ALCL specimens, but extra copies were detected in 24

  13. Molecular cloning of MSSP-2, a c-myc gene single-strand binding protein: characterization of binding specificity and DNA replication activity.

    OpenAIRE

    Takai, Toshiki; Nishita, Yoshinori; Iguchi-Ariga, Sanae M. M.; Ariga, Hiroyoshi

    1994-01-01

    We have previously reported the human cDNA encoding MSSP-1, a sequence-specific double- and single-stranded DNA binding protein [Negishi, Nishita, Saëgusa, Kakizaki, Galli, Kihara, Tamai, Miyajima, Iguchi-Ariga and Ariga (1994) Oncogene, 9, 1133-1143]. MSSP-1 binds to a DNA replication origin/transcriptional enhancer of the human c-myc gene and has turned out to be identical with Scr2, a human protein which complements the defect of cdc2 kinase in S.pombe [Kataoka and Nojima (1994) Nucleic Ac...

  14. Promoter-associated noncoding RNA from the CCND1 promoter.

    Science.gov (United States)

    Song, Xiaoyuan; Wang, Xiangting; Arai, Shigeki; Kurokawa, Riki

    2012-01-01

    More than 90% of the human genome have been found to be transcribed and most of the transcripts are noncoding (nc) RNAs (Willingham et al., Science 309:1570-1573, 2005; ENCODE-consortium, Science 306:636-640, 2004; Carninci et al., Science 309:1559-1563, 2005; Bertone et al., Science 306:2242-2246, 2004). Studies on ncRNAs have been radically progressed mainly regarding microRNAs, piRNAs, siRNAs, and related small ncRNAs of which length are relatively short nucleotides (Fire et al., Nature 391:806-811, 1998; Filipowicz et al., Nat Rev Genet 9:102-114, 2008; Lau et al., Science 313:363-367, 2006; Brennecke et al., Science 322:1387-1392, 2008; Siomi and Siomi, Nature 457:396-404, 2009). These small RNAs play roles in regulation of translation and gene silencing while long ncRNAs with length more than 200 nucleotides have been emerging and turn out to be involved in regulation of transcription (Kapranov et al., Science 316:1484-1488, 2007; Ponting et al., Cell 136:629-641, 2009; Kurokawa et al., RNA Biol 6:233-236, 2009). Recently, we have identified novel, long ncRNAs bearing capability of repression of transcription (Wang et al., Nature 454:126-130, 2008).RNA-binding protein, translocated in liposarcoma (TLS), binds CREB-binding protein CBP/adenovirus p300 and inhibits their histone acetyltransferase (HAT) activities (Wang et al., Nature 454:126-130, 2008). The HAT inhibitory activity of TLS requires specific binding of RNA. The systematic evolution of ligands by exponential enrichment experiments with randomized sequences revealed that TLS specifically recognizes RNA oligonucleotides containing GGUG as a consensus sequence although the GGUG sequence is not an absolute requirement for the TLS binding (Lerga et al., J Biol Chem 276:6807-6816, 2001). TLS is specifically recruited to the CBP/p300-associated binding sites of the cyclin D1 gene (CCND1) and the cyclin E1 gene (CCNE1) promoters (Wang et al., Nature 454:126-130, 2008; Impey et al., Cell 119:1041-1054, 2004

  15. c-Myc regulates cell proliferation during lens development.

    Directory of Open Access Journals (Sweden)

    Gabriel R Cavalheiro

    Full Text Available Myc protooncogenes play important roles in the regulation of cell proliferation, growth, differentiation and survival during development. In various developing organs, c-myc has been shown to control the expression of cell cycle regulators and its misregulated expression is detected in many human tumors. Here, we show that c-myc gene (Myc is highly expressed in developing mouse lens. Targeted deletion of c-myc gene from head surface ectoderm dramatically impaired ocular organogenesis, resulting in severe microphtalmia, defective anterior segment development, formation of a lens stalk and/or aphakia. In particular, lenses lacking c-myc presented thinner epithelial cell layer and growth impairment that was detectable soon after its inactivation. Defective development of c-myc-null lens was not caused by increased cell death of lens progenitor cells. Instead, c-myc loss reduced cell proliferation, what was associated with an ectopic expression of Prox1 and p27(Kip1 proteins within epithelial cells. Interestingly, a sharp decrease in the expression of the forkhead box transcription factor Foxe3 was also observed following c-myc inactivation. These data represent the first description of the physiological roles played by a Myc family member in mouse lens development. Our findings support the conclusion that c-myc regulates the proliferation of lens epithelial cells in vivo and may, directly or indirectly, modulate the expression of classical cell cycle regulators in developing mouse lens.

  16. NM23-H2 may play an indirect role in transcriptional activation of c-myc gene expression but does not cleave the nuclease hypersensitive element III[subscript 1

    Energy Technology Data Exchange (ETDEWEB)

    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. (Ariz)

    2009-05-13

    The formation of G-quadruplex structures within the nuclease hypersensitive element (NHE) III{sub 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{sub 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{sub 1} and, to a lesser extent, to a random single-stranded DNA template. However, it does not bind to or cleave the NHE III{sub 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{sup 88} to Ala{sup 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{sub 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. Evolutionary conservation of CCND1-ORAOV1-FGF19-FGF4 locus from zebrafish to human.

    Science.gov (United States)

    Katoh, Masuko; Katoh, Masaru

    2003-07-01

    The CCND1-ORAOV1-FGF19-FGF4-FGF3-FLJ10261-FADD-PPFIA1-EMS1 locus on human chromosome 11q13 is frequently amplified in esophageal cancer, breast cancer, and bladder tumors. FGF19, FGF4 and FGF3 genes are implicated in embryogenesis and carcinogenesis. We proposed in 2002 the hypothesis that mouse Fgf15 might be the ortholog of human FGF19 based on comparative genomics. Here, we identified zebrafish fgf19 and oraov1 genes by using bioinformatics to demonstrate the hypothesis. Zebrafish fgf19 gene, consisting of three exons, was located around nucleotide position 121802-124963 of zebrafish genome draft sequence AL929586.12 in the reverse orientation. Zebrafish fgf19 (209 aa) was more homologous to chicken fgf19 and human FGF19 than to rodent Fgf15. Zebrafish oraov1 gene, consisting of five exons, was located around nucleotide position 112172-115838 of AL929586.12 in the reverse orientation. Zebrafish oraov1 protein (141 aa) was more homologous to human ORAOV1 than to rodent Oraov1. The CCND1-ORAOV1-FGF19-FGF4 locus was well conserved between human and zebrafish genomes in the order of genes, in the direction of genes, and in the exon-intron structure. Rat Ccnd1-Oraov1-Fgf15-Fgf4 locus was synthenic to mouse Ccnd1-Oraov1 (also known as 2210010N10Rik)-Fgf15-Fgf4 locus. Fgf15, homologous to human FGF19 and zebrafish fgf19, was located on the synthenic locus of human FGF19 and zebrafish fgf19 within rodent genomes. Based on the evolutionary conservation of the CCND1-ORAOV1-FGF19-FGF4 locus from zebrafish to human, it was concluded that Fgf15 gene is the rodent ortholog of human FGF19 gene.

  18. Investigating actinomycin D binding to G-quadruplex, i-motif and double-stranded DNA in 27-nt segment of c-MYC gene promoter.

    Science.gov (United States)

    Niknezhad, Zhila; Hassani, Leila; Norouzi, Davood

    2016-01-01

    c-MYC DNA is an attractive target for drug design, especially for cancer chemotherapy. Around 90% of c-MYC transcription is controlled by NHE III1, whose 27-nt purine-rich strand has the ability to form G-quadruplex structure. In this investigation, interaction of ActD with 27-nt G-rich strand (G/c-MYC) and its equimolar mixture with the complementary sequence, (GC/c-MYC) as well as related C-rich oligonucleotide (C/c-MYC) was evaluated. Molecular dynamic simulations showed that phenoxazine and lactone rings of ActD come close to the outer G-tetrad nucleotides indicating that ActD binds through end-stacking to the quadruplex DNA. RMSD and RMSF revealed that fluctuation of the quadruplex DNA increases upon interaction with the drug. The results of spectrophotometry and spectrofluorometry indicated that ActD most probably binds to the c-MYC quadruplex and duplex DNA via end-stacking and intercalation, respectively and polarity of ActD environment decreases due to the interaction. It was also found that binding of ActD to the GC-rich DNA is stronger than the two other forms of DNA. Circular dichroism results showed that the type of the three forms of DNA structures doesn't change, but their compactness alters due to their interaction with ActD. Finally, it can be concluded that ActD binds differently to double stranded DNA, quadruplex DNA and i-motif.

  19. The Role of c-MYC in B-Cell Lymphomas: Diagnostic and Molecular Aspects.

    Science.gov (United States)

    Nguyen, Lynh; Papenhausen, Peter; Shao, Haipeng

    2017-04-05

    c-MYC is one of the most essential transcriptional factors, regulating a diverse array of cellular functions, including proliferation, growth, and apoptosis. Dysregulation of c-MYC is essential in the pathogenesis of a number of B-cell lymphomas, but is rarely reported in T-cell lymphomas. c-MYC dysregulation induces lymphomagenesis by loss of the tight control of c-MYC expression, leading to overexpression of intact c-MYC protein, in contrast to the somatic mutations or fusion proteins seen in many other oncogenes. Dysregulation of c-MYC in B-cell lymphomas occurs either as a primary event in Burkitt lymphoma, or secondarily in aggressive lymphomas such as diffuse large B-cell lymphoma, plasmablastic lymphoma, mantle cell lymphoma, or double-hit lymphoma. Secondary c-MYC changes include gene translocation and gene amplification, occurring against a background of complex karyotype, and most often confer aggressive clinical behavior, as evidenced in the double-hit lymphomas. In low-grade B-cell lymphomas, acquisition of c-MYC rearrangement usually results in transformation into highly aggressive lymphomas, with some exceptions. In this review, we discuss the role that c-MYC plays in the pathogenesis of B-cell lymphomas, the molecular alterations that lead to c-MYC dysregulation, and their effect on prognosis and diagnosis in specific types of B-cell lymphoma.

  20. 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.

  1. Estrogen Receptor-α and Its Target Gene c-Myc and Pre-implantation Embryos%雌激素受体α及其靶基因c-Myc与植入前胚

    Institute of Scientific and Technical Information of China (English)

    张燕琴

    2012-01-01

    Estrogen receptor-α(Erα), member of the steroid hormone receptor gene superfamily that acts as ligand-inducible transcription factor and plays an important role in regulating the proliferation, differentiation and development of cells and tissues. C-Myc,the Erα target gene,which belongs to Myc gene family, is a kind of nucleoprotein class protooncogene. Erα regulates the expression of c-Myc, at the same time,the expression of c-Myc changing also affects the function of Erα,they are associated with each other. Erα and c-Myc expression are stage-specific in preimplantation embryos, suggesting that their functions might be involved in the development of mammalian preimplantation embryos.%雌激素受体α(ERα)属于类固醇激素受体超家族,是细胞核中需要配体激活的转录因子,对细胞和组织的增殖、分化和发育有重要的调节作用.c-Myc是ERα目的 基因,属于Myc基因家族,是一种核蛋白类的原癌基因.ERα调控着c-Myc的表达,而c-Myc的表达变化也影响着ERα的功能发挥,彼此之间存在关联.它们在哺乳动物植入前胚中呈阶段特异性表达,在植入前胚发育中发挥一定作用.

  2. Constitutive CCND1/CDK2 activity substitutes for p53 loss, or MYC or oncogenic RAS expression in the transformation of human mammary epithelial cells.

    Directory of Open Access Journals (Sweden)

    Damian J Junk

    Full Text Available Cancer develops following the accumulation of genetic and epigenetic alterations that inactivate tumor suppressor genes and activate proto-oncogenes. Dysregulated cyclin-dependent kinase (CDK activity has oncogenic potential in breast cancer due to its ability to inactivate key tumor suppressor networks and drive aberrant proliferation. Accumulation or over-expression of cyclin D1 (CCND1 occurs in a majority of breast cancers and over-expression of CCND1 leads to accumulation of activated CCND1/CDK2 complexes in breast cancer cells. We describe here the role of constitutively active CCND1/CDK2 complexes in human mammary epithelial cell (HMEC transformation. A genetically-defined, stepwise HMEC transformation model was generated by inhibiting p16 and p53 with shRNA, and expressing exogenous MYC and mutant RAS. By replacing components of this model, we demonstrate that constitutive CCND1/CDK2 activity effectively confers anchorage independent growth by inhibiting p53 or replacing MYC or oncogenic RAS expression. These findings are consistent with several clinical observations of luminal breast cancer sub-types that show elevated CCND1 typically occurs in specimens that retain wild-type p53, do not amplify MYC, and contain no RAS mutations. Taken together, these data suggest that targeted inhibition of constitutive CCND1/CDK2 activity may enhance the effectiveness of current treatments for luminal breast cancer.

  3. Expression of Cyclin d1 protein and CCND1 та PNKP genes in peripheral blood mononuclear cells in clean up worker of Chornobyl accident with different state of immune system.

    Science.gov (United States)

    Bazyka, D A; Kubashko, A V; Ilyenko, I M; Belyaev, O A; Pleskach, O J

    2015-12-01

    Meta. Doslidyty zminy rivniv Cyclin D1+ klityn ta asotsiyovanykh geniv CCND1 ta PNKP u mononuklearakh peryfe rychnoI krovi v uchasnykiv likvidatsiI naslidkiv avariI (ULNA) na ChAES z riznym imunnym statusom v zalezhnosti vid dozy oprominennia.Materialy i metody. Proanalizovano vidnosnyy riven' Cyclin D1+ klityn u mononuklearakh peryferychnoI krovi 39 ULNA na ChAES, cholovikiv, oprominenykh u dozi u diapazoni (0,01–2,00) Gr. Imunologichnyy status obstezhenykh vyz nachavsia za rivnem CD3/19, CD4/8, CD3/HLA DR, SD3/16/56 metodom protochnoI tsytofluorymetriI ta za vmistom Ig klasiv A,M,G metodom imunofermentnogo analizu u krovi. Ekspresiia geniv CCND1 ta PNKP, iaki pov’iazani z Syclin D1, provodylos' za metodom polimeraznoI lantsiugovoI reaktsiI u real'nomu chasi. Porivniannia rezul'tativ zdiysniuva los' iz vidpovidnymy danymy, otrymanymy vid 18 zdorovykh cholovikiv, iaki ne maly kontaktu z ionizuiuchym vyp rominiuvanniam vyshche pryrodn'ogo fonu.Rezul'taty. Pokazano, shcho vidsotok Suclin D1+ klityn zbil'shuiet'sia za normu v osib, oprominenykh u dozi > 0,1 Gr, ta koreliuie z dozoiu oprominennia (rs = 0,417, p = 0,048). Vidkhylennia rivnia Cyclin D1+ klityn za mezhi kontrol'nykh zna chen' pov’iazuiet'sia zi zminamy v klitynniy ta gumoral'niy lankakh imunitetu. Zmenshennia vidsotku Cyclin D1+ klityn za mezhi kontrol'nykh znachen' v ULNA na ChAES iz dozoiu 0,35 Gr, zbil'shennia vidsotku Cyclin D1+ klityn asotsiiuiet'sia zi znyzhenniam CD3+ ta tendentsiieiu shchodo znyzhennia CD3+16+56+ limfotsytiv u poiednanni zi zbil'shen niam rivnia IgG. Zbil'shennia rivniv CD4+, CD19+, Ireg. ta IgG suprovodzhuiet'sia poiavoiu koreliatsiynykh zv’iazkiv mizh Cyclin D1+ ta CD3 16+56+ klitynamy (rs = 0,872, p = 0,049), Cyclin D1+ ta CD8+ i IgG (rs = 0,683, p = 0,042; rs = 0,809, p = 0,014), Cyclin D1+ ta CD4+ (rs = 0,602, p = 0,029), Cyclin D1+ ta CD19+ i IgM (rs = 0,604, p = 0,017; rs = 0,538, p = 0,038) vidpovidno. V ULNA, oprominenykh u dozi > 0,1 Gr, fiksuiet'sia znyzhennia

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

    Directory of Open Access Journals (Sweden)

    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.

  5. The Essential Cofactor TRRAP Recruits the Histone Acetyltransferase hGCN5 to c-Myc

    Science.gov (United States)

    McMahon, Steven B.; Wood, Marcelo A.; Cole, Michael D.

    2000-01-01

    The c-Myc protein functions as a transcription factor to facilitate oncogenic transformation; however, the biochemical and genetic pathways leading to transformation remain undefined. We demonstrate here that the recently described c-Myc cofactor TRRAP recruits histone acetylase activity, which is catalyzed by the human GCN5 protein. Since c-Myc function is inhibited by recruitment of histone deacetylase activity through Mad family proteins, these opposing biochemical activities are likely to be responsible for the antagonistic biological effects of c-Myc and Mad on target genes and ultimately on cellular transformation. PMID:10611234

  6. Effect of C-myc Antisense Oligodeoxynucleotides on Hypoxia-induced Proliferation of Pulmonary Vascular Pericytes

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    To study the effect of c-myc antisense oligodeoxynucleotides (ODNs) on proliferation of pulmonary vascular pericytes (PC) induced by hypoxia, cell culture, dot hybridization using probe of digoxigenin-11-dUTP-labeled cDNA,3H-thymidine incorporation, immunocytochemical technique and image analysis methods were used to observe the effect of c-myc antisense ODNs on expression of c-myc gene and proliferating cell nuclear antigen (PCNA), and 3H-thymidine incorporation of PC induced by hypoxia. The results showed that hypoxia could significantly enhance the expression of c-myc and PCNA (P<0.01), and elevate 3H-thymidine incorporation of PC (P<0.01), but antisense ODNs could significantly inhibit the expression of c-myc and PCNA (P<0.05), and 3H-thymidine incorporation of PC (P<0.01). It was suggested that hypoxia could promote the proliferation of PC by up-regulating the expression of c-myc gene, but c-myc antisense ODNs could inhibit hypoxia-induced proliferation of PC by downregulating the expression of c-myc gene.

  7. 人类p53和c-myc同源基因在玉米颖果发育过程中的表达%Expressions of Human p53 and c-myc Gene Homologues During Caryopsis Development in Maize

    Institute of Scientific and Technical Information of China (English)

    亓翠英; 宁顺斌; 王宁; 李立家; 宋运淳

    2003-01-01

    肿瘤抑制基因p53和原癌基因c-myc已被证明在动物中高度保守并参与许多PCD过程.这两个基因编码的同源蛋白及其RNA在玉米中的存在已有报道,并且其DNA同源序列已利用荧光原位杂交定位在玉米相应的染色体上.利用免疫组织化学方法探测了与人类p53和c-myc基因同源的玉米基因在玉米颖果发育过程中的时空表达模式.结果发现,在授粉后的一定阶段,在反足细胞、珠被、未成熟的胚乳、子房壁、导管组织和糊粉层中,p53同源基因表达强烈,c-myc同源基因的表达相反,在授粉后的这些组织中基本不表达,而在授粉前的中央细胞的极核中表达水平较高.TUNEL检测显示,在p53同源基因呈现高水平表达的地方,DNA断裂信号强烈.在动物细胞中,p53和c-myc起相反的调节作用,这与其同源基因在玉米中的作用模式相似.由此说明p53和c-myc同源基因可能在玉米颖果发育PCD过程中起重要作用,并进一步推论高等植物PCD和动物细胞凋亡存在一定的保守性机制.%Tumor suppressor gene p53 and proto-oncogene c-myc have been proved to be highly conserved and participate in many PCD processes in animals.In maize,proteins and RNAs related to p53 and c-myc have already been reported and the sequences homologous to these two genes have also been localized onto maize chromosomes by FISH.In this study,using immunohistochemistry we investigated the expression patterns of maize genes homologous to human p53 and c-myc during caryopsis development stages in maize.In a giving stage after pollination,p53 homologue showed high levels in the antipodal cells,integument,immature endosperm,ovary wall,tracheary elements,and aleurone layer,while c-myc homologue showed low levels in these tissues,only before pollination showed high expression in polar nucleus.The results of TUNEL assay demonstrated that TUNEL positive signals were detected where p53 homologue showed high expression

  8. Heterogeneous abnormalities of CCND1 and RB1 in primary cutaneous T-Cell lymphomas suggesting impaired cell cycle control in disease pathogenesis.

    Science.gov (United States)

    Mao, Xin; Orchard, Guy; Vonderheid, Eric C; Nowell, Peter C; Bagot, Martine; Bensussan, Armand; Russell-Jones, Robin; Young, Bryan D; Whittaker, Sean J

    2006-06-01

    Upregulation of cyclin D1/B-cell leukemia/lymphoma 1 (CCND1/BCL1) is present in most mantle cell lymphomas with the t(11;14)(q13;q32) translocation. However, little is known about the abnormalities of CCND1 and its regulator RB1 in primary cutaneous T-cell lymphomas (CTCL). We analyzed CCND and RB status in CTCL using fluorescent in situ hybridization (FISH), immunohistochemistry (IHC), and Affymetrix expression microarray. FISH revealed loss of CCND1/BCL1 in five of nine Sézary syndrome (SS) cases but gain in two cases, and RB1 loss in four of seven SS cases. IHC showed absent CCND1/BCL1 expression in 18 of 30 SS, 10 of 23 mycosis fungoides (MF), and three of 10 primary cutaneous CD30+ anaplastic large-cell lymphoma (C-ALCL). Increased CCND1/BCL1 expression was seen in nine MF, seven C-ALCL, and six SS cases. Absent RB1 expression was detected in 8 of 12 MF and 7 of 9 SS cases, and raised RB1 expression in 7 of 8 C-ALCL. Affymetrix revealed increased gene expression of CCND2 in four of eight CTCL cases, CCND3 in three cases, and CDKN2C in two cases with a normal expression of CCND1 and RB1. These findings suggest heterogeneous abnormalities of CCND and RB in CTCL, in which dysregulated CCND and RB1 may lead to impaired cell cycle control.

  9. Deregulation of c-myc and SV40Tag causing brain tumor in mice

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Deregulated expressions of both c-myc and simian virus 40 large T antigen (SV40Tag) are consistent features of lots of tumors. To investigate whether the expression of c-myc and SV40Tag in mouse might help develop a model of human tumor, we generated c-myc transgenics by inserting human c-myc gene into pTRE2 of Tet-On system. We obtained conditional expression of SV40Tag transgenics by the Tet-On system from Yangzhou University. Crossing the c-myc transgenic mouse with the SV40Tag transgenic mice to generate bitransgenics we got double-transgenic mice expressing c-myc and SV40Tag by the Tet-On system. After being treated with doxycycline continuously, single-transgenic SV40Tag mice developed brain tumor infrequently (3 of 84, 3.6%) with a long onset (185 d on average). In contrast, double-transgenic c-myc/SV40Tag mice developed brain tumor with a short onset (96 days on average) and a 41% brain tumor incidence rate (7 of 17, 41%). This tumor was assumed to be medulloblastoma. Our experiments suggest that deregulated expression of c-myc and SV40Tag in brain might generate a mouse model of human brain tumor that recapitulates some features of human medulloblastoma.

  10. HBXIP and LSD1 Scaffolded by lncRNA Hotair Mediate Transcriptional Activation by c-Myc.

    Science.gov (United States)

    Li, Yinghui; Wang, Zhen; Shi, Hui; Li, Hang; Li, Leilei; Fang, Runping; Cai, Xiaoli; Liu, Bowen; Zhang, Xiaodong; Ye, Lihong

    2016-01-15

    c-Myc is regarded as a transcription factor, but the basis for its function remains unclear. Here, we define a long noncoding RNA (lncRNA)/protein complex that mediates the transcriptional activation by c-Myc in breast cancer cells. Among 388 c-Myc target genes in human MCF-7 breast cancer cells, we found that their promoters could be occupied by the oncoprotein HBXIP. We confirmed that the HBXIP expression correlated with expression of the c-Myc target genes cyclin A, eIF4E, and LDHA. RNAi-mediated silencing of HBXIP abolished c-Myc-mediated upregulation of these target genes. Mechanistically, HBXIP interacted directly with c-Myc through the leucine zippers and recruited the lncRNA Hotair along with the histone demethylase LSD1, for which Hotair serves as a scaffold. Silencing of HBXIP, Hotair, or LSD1 was sufficient to block c-Myc-enhanced cancer cell growth in vitro and in vivo. Taken together, our results support a model in which the HBXIP/Hotair/LSD1 complex serves as a critical effector of c-Myc in activating transcription of its target genes, illuminating long-standing questions on how c-Myc drives carcinogenesis.

  11. Increased transcription of the c-myc oncogene in two methylcholanthrene-induced quail fibroblastic cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Saule, S.; Martin, P.; Gegonne, A.; Begue, A.; Lagrou, C.; Stehelin, D.

    1984-12-01

    The expression of three c-onc genes (c-erb, c-myc, c-myb) was investigated in five cell lines established from fibrosarcomas induced with 20-methylcholanthrene (MCA) of Japanese quails. These cell lines showed low levels of the three c-onc genes, with the exception of two cell lines that accumulated moderate (MCAQ 1-4) and large amounts (MCAQ 3-5) of c-myc RNA. Molecular cloning and restriction endonuclease analyses indicated that expression of c-myc in these two cell lines were not associated with detectable rearrangements in the c-myc locus, that the size of the c-myc transcript (2.7 kb) in MCAQ 3-5 was similar to that of the normal c-myc messenger RNAs (mRNA) and that the transcriptional activatin observed in MCAQ 3-5 was not mediated by the LTR (long terminal repeat) of a proximate ALV (avian leukosis virus) provirus. Finally, when analyzed with the restriction enzymes Msp I and Hpa II, the c-myc locus of MCAQ 3-5 and MCAQ 1-4 was found hypomethylated as compared with that of the other cell lines tested that show low levels of c-myc transcripts. Results suggest that one of the ways methylcholanthrene could mediate transformation is by inducing an abnormal regulation of the c-myc gene.

  12. CCND1 mutations increase protein stability and promote ibrutinib resistance in mantle cell lymphoma.

    Science.gov (United States)

    Mohanty, Atish; Sandoval, Natalie; Das, Manasi; Pillai, Raju; Chen, Lu; Chen, Robert W; Amin, Hesham M; Wang, Michael; Marcucci, Guido; Weisenburger, Dennis D; Rosen, Steven T; Pham, Lan V; Ngo, Vu N

    2016-11-08

    Mantle cell lymphoma (MCL) is characterized by the t(11;14) translocation, which leads to deregulated expression of the cell cycle regulatory protein cyclin D1 (CCND1). Genomic studies of MCL have also identified recurrent mutations in the coding region of CCND1. However, the functional consequence of these mutations is not known. Here, we showed that, compared to wild type (WT), single E36K, Y44D or C47S CCND1 mutations increased CCND1 protein levels in MCL cell lines. Mechanistically, these mutations stabilized CCND1 protein through attenuation of threonine-286 phosphorylation, which is important for proteolysis through the ubiquitin-proteasome pathway. In addition, the mutant proteins preferentially localized to the nucleus. Interestingly, forced expression of WT or mutant CCND1 increased resistance of MCL cell lines to ibrutinib, an FDA-approved Bruton tyrosine kinase inhibitor for MCL treatment. The Y44D mutant sustained the resistance to ibrutinib even at supraphysiologic concentrations (5-10 μM). Furthermore, primary MCL tumors with CCND1 mutations also expressed stable CCND1 protein and were resistant to ibrutinib. These findings uncover a new mechanism that is critical for the regulation of CCND1 protein levels, and is directly relevant to primary ibrutinib resistance in MCL.

  13. TIP30 interacts with an estrogen receptor alpha-interacting coactivator CIA and regulates c-myc transcription.

    Science.gov (United States)

    Jiang, Chao; Ito, Mitsuhiro; Piening, Valerie; Bruck, Kristy; Roeder, Robert G; Xiao, Hua

    2004-06-25

    Deregulation of c-myc expression is implicated in the pathogenesis of many neoplasias. Estrogen receptor alpha (ERalpha) can increase the rate of c-myc transcription through the recruitment of a variety of cofactors to the promoter, yet the precise roles of these cofactors in transcription and tumorigenesis are largely unknown. We show here that a putative tumor suppressor TIP30, also called CC3 or Htatip2, interacts with an ERalpha-interacting coactivator CIA. Using chromatin immunoprecipitation assays, we demonstrate that TIP30 and CIA are distinct cofactors that are dynamically associated with the promoter and downstream regions of the c-myc gene in response to estrogen. Both TIP30 and CIA are recruited to the c-myc gene promoter by liganded ERalpha in the second transcription cycle. TIP30 overexpression represses ERalpha-mediated c-myc transcription, whereas TIP30 deficiency enhances c-myc transcription in both the absence and presence of estrogen. Ectopic CIA cooperates with TIP30 to repress ERalpha-mediated c-myc transcription. Moreover, virgin TIP30 knockout mice exhibit increased c-myc expression in mammary glands. Together, these results reveal an important role for TIP30 in the regulation of ERalpha-mediated c-myc transcription and suggest a mechanism for tumorigenesis promoted by TIP30 deficiency.

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

    Institute of Scientific and Technical Information of China (English)

    Danielle Queiroz Calcagno; Márcia Valéria Pitombeira Ferreira; Marília de Arruda Cardoso Smith; Rommel Rodríguez Burbano; Mariana Ferreira Leal; Aline Damaceno Seabra; André Salim Khayat; Elizabeth Suchi Chen; Samia Demachki; Paulo Pimentel Assump(c)(a)o; Mario Henrique Gir(a)o Faria; Silvia Helena Barem Rabenhorst

    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 8centromere 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 intestinaltype 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  16. 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.

  17. Lack of Cyclin-Dependent Kinase 4 Inhibits c-myc Tumorigenic Activities in Epithelial Tissues

    OpenAIRE

    Miliani de Marval, Paula L; Macias, Everardo; Rounbehler, Robert; Sicinski, Piotr; Kiyokawa, Hiroaki; Johnson, David G.; Conti, Claudio J; Rodriguez-Puebla, Marcelo L.

    2004-01-01

    The proto-oncogene c-myc encodes a transcription factor that is implicated in the regulation of cellular proliferation, differentiation, and apoptosis and that has also been found to be deregulated in several forms of human and experimental tumors. We have shown that forced expression of c-myc in epithelial tissues of transgenic mice (K5-Myc) resulted in keratinocyte hyperproliferation and the development of spontaneous tumors in the skin and oral cavity. Although a number of genes involved i...

  18. Therapeutic aspects of c-MYC signaling in inflammatory and cancerous colonic diseases.

    Science.gov (United States)

    Sipos, Ferenc; Firneisz, Gábor; Műzes, Györgyi

    2016-09-21

    Colonic inflammation is required to heal infections, wounds, and maintain tissue homeostasis. As the seventh hallmark of cancer, however, it may affect all phases of tumor development, including tumor initiation, promotion, invasion and metastatic dissemination, and also evasion immune surveillance. Inflammation acts as a cellular stressor and may trigger DNA damage or genetic instability, and, further, chronic inflammation can provoke genetic mutations and epigenetic mechanisms that promote malignant cell transformation. Both sporadical and colitis-associated colorectal carcinogenesis are multi-step, complex processes arising from the uncontrolled proliferation and spreading of malignantly transformed cell clones with the obvious ability to evade the host's protective immunity. In cells upon DNA damage several proto-oncogenes, including c-MYC are activated in parelell with the inactivation of tumor suppressor genes. The target genes of the c-MYC protein participate in different cellular functions, including cell cycle, survival, protein synthesis, cell adhesion, and micro-RNA expression. The transcriptional program regulated by c-MYC is context dependent, therefore the final cellular response to elevated c-MYC levels may range from increased proliferation to augmented apoptosis. Considering physiological intestinal homeostasis, c-MYC displays a fundamental role in the regulation of cell proliferation and crypt cell number. However, c-MYC gene is frequently deregulated in inflammation, and overexpressed in both sporadic and colitis-associated colon adenocarcinomas. Recent results demonstrated that endogenous c-MYC is essential for efficient induction of p53-dependent apoptosis following DNA damage, but c-MYC function is also involved in and regulated by autophagy-related mechanisms, while its expression is affected by DNA-methylation, or histone acetylation. Molecules directly targeting c-MYC, or agents acting on other genes involved in the c-MYC pathway could be

  19. Therapeutic aspects of c-MYC signaling in inflammatory and cancerous colonic diseases

    Science.gov (United States)

    Sipos, Ferenc; Firneisz, Gábor; Műzes, Györgyi

    2016-01-01

    Colonic inflammation is required to heal infections, wounds, and maintain tissue homeostasis. As the seventh hallmark of cancer, however, it may affect all phases of tumor development, including tumor initiation, promotion, invasion and metastatic dissemination, and also evasion immune surveillance. Inflammation acts as a cellular stressor and may trigger DNA damage or genetic instability, and, further, chronic inflammation can provoke genetic mutations and epigenetic mechanisms that promote malignant cell transformation. Both sporadical and colitis-associated colorectal carcinogenesis are multi-step, complex processes arising from the uncontrolled proliferation and spreading of malignantly transformed cell clones with the obvious ability to evade the host’s protective immunity. In cells upon DNA damage several proto-oncogenes, including c-MYC are activated in parelell with the inactivation of tumor suppressor genes. The target genes of the c-MYC protein participate in different cellular functions, including cell cycle, survival, protein synthesis, cell adhesion, and micro-RNA expression. The transcriptional program regulated by c-MYC is context dependent, therefore the final cellular response to elevated c-MYC levels may range from increased proliferation to augmented apoptosis. Considering physiological intestinal homeostasis, c-MYC displays a fundamental role in the regulation of cell proliferation and crypt cell number. However, c-MYC gene is frequently deregulated in inflammation, and overexpressed in both sporadic and colitis-associated colon adenocarcinomas. Recent results demonstrated that endogenous c-MYC is essential for efficient induction of p53-dependent apoptosis following DNA damage, but c-MYC function is also involved in and regulated by autophagy-related mechanisms, while its expression is affected by DNA-methylation, or histone acetylation. Molecules directly targeting c-MYC, or agents acting on other genes involved in the c-MYC pathway could be

  20. Overexpression of c-myc induces epithelial mesenchymal transition in mammary epithelial cells.

    Science.gov (United States)

    Cho, Kyoung Bin; Cho, Min Kyong; Lee, Won Young; Kang, Keon Wook

    2010-07-28

    The c-myc gene is frequently overexpressed in human breast cancer and its target genes are involved in tumorigenesis. Epithelial mesenchymal transitions (EMT), where cells undergo a developmental switch from a polarized epithelial phenotype to a highly motile mesenchymal phenotype, are associated with invasion and motility of cancer cells. Basal E-cadherin expression was down-regulated in c-myc overexpressing MCF10A (c-myc-MCF10A) cells compared to GFP-overexpressing MCF10A (GFP-MCF10A) cells, while N-cadherin was distinctly increased in c-myc-MCF10A cells. Given that glycogen synthase kinase-3beta (GSK-3beta) and the snail axis have key roles in E-cadherin deregulation during EMT, we investigated the role of GSK-3beta/snail signaling pathways in the induction of EMT by c-myc overexpression. In contrast to GFP-MCF10A cells, both the transcriptional activity and the ubiquitination-dependent protein stability of snail were enhanced in c-myc-MCF10A cells, and this was reversed by GSK-3beta overexpression. We also found that c-myc overexpression inhibits GSK-3beta activity through activation of extracellular signal-regulated kinase (ERK). Inhibition of ERK by dominant negative mutant transfection or chemical inhibitor significantly suppressed snail gene transcription. These results suggest that c-myc overexpression during transformation of mammary epithelial cells (MEC) is involved in EMTs via ERK-dependent GSK-3beta inactivation and subsequent snail activation.

  1. The c-Myc Transactivation Domain Is a Direct Modulator of Apoptotic versus Proliferative Signals

    Science.gov (United States)

    Chang, David W.; Claassen, Gisela F.; Hann, Stephen R.; Cole, Michael D.

    2000-01-01

    We have assayed the oncogenic, proliferative, and apoptotic activities of the frequent mutations that occur in the c-myc gene in Burkitt's lymphomas. Some alleles have a modest (50 to 60%) increase in transforming activity; however, the most frequent Burkitt's lymphoma allele (T58I) had an unexpected substantial decrease in transforming activity (85%). All alleles restored the proliferation function of c-Myc in cells that grow slowly due to a c-myc knockout. There was discordance for some alleles between apoptotic and oncogenic activities, but only the T58A allele had elevated transforming activity with a concomitant reduced apoptotic potential. We discovered a novel missense mutation, MycS71F, that had a very low apoptotic activity compared to wild-type Myc, yet this mutation has never been found in lymphomas, suggesting that there is no strong selection for antiapoptotic c-Myc alleles. MycS71F also induced very low levels of cytochrome c release from mitochondria, suggesting a mechanism of action for this mutation. Phosphopeptide mapping provided a biochemical basis for the dramatically different biological activities of the transformation-defective T58I and transformation-enhanced T58A c-Myc alleles. Furthermore, the antiapoptotic survival factor insulin-like growth factor 1 was found to suppress phosphorylation of T58, suggesting that the c-Myc transactivation domain is a direct target of survival signals. PMID:10825194

  2. Regulation of human ornithine decarboxylase expression by the c-Myc.Max protein complex.

    Science.gov (United States)

    Peña, A; Reddy, C D; Wu, S; Hickok, N J; Reddy, E P; Yumet, G; Soprano, D R; Soprano, K J

    1993-12-25

    The presence of a CACGTG element within a region of the human ornithine decarboxylase (ODC) promoter located at -491 to -474 base pairs 5' to the start site of transcription suggested that the c-Myc.Max protein complex may play a role in the regulation of ODC expression during growth. Electrophoretic mobility shift assays and methylation interference analysis showed that the nuclei of WI-38 cells expressing ODC contained proteins that bound to this region of the ODC gene in a manner that correlated with growth-associated ODC expression. Also, use of antibodies against c-Myc and Max and purified recombinant c-Myc and Max protein in the electrophoretic mobility shift assay confirmed that these proteins can specifically bind this portion of the human ODC promoter. Transient transfection studies showed that increase in the level of c-Myc and/or Max led to a significant enhancement of expression of a human ODC promoter-CAT reporter construct. Moreover, treatment of actively growing WI-38 cells with an antisense oligomer to c-Myc reduced the amount of endogenous protein complex formed and the amount of endogenous ODC mRNA expressed. These studies show that the c-Myc.Max protein complex plays a role in the transcriptional regulation of human ODC in vivo.

  3. Transactivation Domain of Human c-Myc Is Essential to Alleviate Poly(Q)-Mediated Neurotoxicity in Drosophila Disease Models.

    Science.gov (United States)

    Raj, Kritika; Sarkar, Surajit

    2017-03-18

    Polyglutamine (poly(Q)) disorders, such as Huntington's disease (HD) and spinocerebellar ataxias, represent a group of neurological disorders which arise due to an atypically expanded poly(Q) tract in the coding region of the affected gene. Pathogenesis of these disorders inside the cells begins with the assembly of these mutant proteins in the form of insoluble inclusion bodies (IBs), which progressively sequester several vital cellular transcription factors and other essential proteins, and finally leads to neuronal dysfunction and apoptosis. We have shown earlier that targeted upregulation of Drosophila myc (dmyc) dominantly suppresses the poly(Q) toxicity in Drosophila. The present study examines the ability of the human c-myc proto-oncogene and also identifies the specific c-Myc isoform which drives the mitigation of poly(Q)-mediated neurotoxicity, so that it could be further substantiated as a potential drug target. We report for the first time that similar to dmyc, tissue-specific induced expression of human c-myc also suppresses poly(Q)-mediated neurotoxicity by an analogous mechanism. Among the three isoforms of c-Myc, the rescue potential was maximally manifested by the full-length c-Myc2 protein, followed by c-Myc1, but not by c-MycS which lacks the transactivation domain. Our study suggests that strategies focussing on the transactivation domain of c-Myc could be a very useful approach to design novel drug molecules against poly(Q) disorders.

  4. 多态性上皮黏蛋白1和原癌基因C-myc在老年甲状腺乳头状癌患者中的表达%Expression changes of mucin1 and c-myc gene in elderly papillary thyroid carcinoma patient

    Institute of Scientific and Technical Information of China (English)

    胡耀杰; 罗晓燕; 杨岳; 陈春悠; 张志勇; 郭欣

    2014-01-01

    Objective To study the changes of expression of mucin1 (MUC1) and protooncogene proteins C-myc (C-myc) gene in elderly papillary thyroid carcinoma.Methods The expression levels of MUC1 and C-myc were examined by immunohistochemical methods in 58 sample of thyroid carcinoma,35 nodular goiter and in 30 normal thyroid tissue.Results The detective rate of MUC1 in 58 specimens of thyroid carcinoma was 77.6% (45/58),while 90.0% (9/10) in those with infiltration and 88.2 % (15/17) in those with metastasis.The detective rate of C-myc in 58 specimens of thyroid carcinoma was 81.0 % (47/58),and 100.0 % (17/17) in those with metastasis.Conclusions The differences in MUC1 or C myc expression and in thyroid carcinoma infiltration and lymph node metastasia between benign versus malignant thyroid tumor are statistically significant.%目的 探讨多态性上皮黏蛋白1 (mucin 1,MUC1)和原癌基因蛋白质(proto-oncogene proteins C-myc,C-Myc)基因在老年甲状腺乳头状癌(PTC)患者中的表达和临床意义. 方法 应用免疫组化法检测30例腺瘤旁正常甲状腺组织、35例结节性甲状腺肿和58例PTC标本中MUC1和C-myc的表达水平. 结果 MUC1基因在甲状腺癌中表达率为77.6%(45/58),MUC1在有局部浸润和淋巴结转移患者中的检出率分别为90.0%(9/10)和88.2%(15/17).C-myc基因在甲状腺癌中阳性率为81.0% (47/58);C-myc在淋巴结转移组中的检出率为100.0% (17/17). 结论 MUC1和C myc的阳性表达在甲状腺良恶性病变间有差异,并与甲状腺癌的转移有关.

  5. VARIATION AND SIGNIFICANCE OF C-MYC PROTEIN IN RAT CARDIAC VOLUME-OVERLOAD HYP ERTROPHY

    Institute of Scientific and Technical Information of China (English)

    刘华胜; 马爱群; 王一理; 刘勇; 李恒力; 田红燕

    2002-01-01

    Objective To investigate the change of c-myc protein, which was chosen as the response indicator to volume-overload. Methods The time and spatial course of c-myc protein expressi on on the model of rat cardiac volume-overload hyper trophy was examined by immunohistochemical study. Results The immunohistochemica l study indicated the expression of c-myc protein was increased obviously at 4 -6 hours (62.73%) than that of control (45.41%, P<0.01) after the volume-o verload, then decreased gradually along with development of volume-overload hyp ertrophy and was decreased extremely at 5 months(r=-0.514,P<0.01).Conclusion There are disorders in the signal transduction pathways governing the hypertrophic respon se of cardiomyocytes in hypertrophic myocardium. C-myc gene and the product of it may be only the promoter gene of myocardial hypertrophy. Once switching on, c-myc gene and the product of it do not act anymore;While it may be that c-my c gene and the product of it increased following with myocardial hypertrophy, an d have not direct relation to the occurrence and development of myocardial hyper trophy.

  6. Burkitt’s lymphoma-associated c-Myc mutations converge on a dramatically altered target gene response and implicate Nol5a/Nop56 in oncogenesis

    Science.gov (United States)

    Cowling, Victoria H.; Turner, Scott A.; Cole, Michael D.

    2016-01-01

    Burkitt’s Lymphomas (BLs) acquire consistent point mutations in a conserved domain of Myc, Myc Box I. We report that the enhanced transforming activity of BL-associated Myc mutants can be uncoupled from loss of phosphorylation and increased protein stability. Furthermore, two different BL-associated Myc mutations induced similar gene expression profiles independently of T58 phosphorylation, and these profiles are dramatically different from MycWT. Nol5a/Nop56, which is required for rRNA methylation, was identified as a gene hyperactivated by the BL-associated Myc mutants. We show that Nol5a is necessary for Myc-induced cell transformation, enhances MycWT-induced cell transformation, and increases the size of MycWT induced tumors. Thus, Nol5a expands the link between Myc-induced regulation of nucleolar target genes which are rate-limiting for cell transformation and tumor growth. PMID:24013231

  7. 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

    central CAC(G/A)TG motif (Henriksson & Prendergast 1999). How the c-Myc protein may be Luscher 1996, Amati et al. 1998, Facchini & Penn 1998...Mycl, c-Myc2, and c-MycS can both activate and repress transcription of specific target (Henriksson & Luscher 1996, Facchini & Penn 1998, Xiao genes...deferens Carcinogenesis 21 427-433. leiomyosarcoma of the Syrian hamster. Cancer Research 30 35- Henriksson M & Luscher B 1996 Proteins of the Myc

  8. Peripheral position of CCND1 and HER-2/neu oncogenes within chromosome territories in esophageal and gastric cancers non-related to amplification and overexpression

    Directory of Open Access Journals (Sweden)

    Lucimari Bizari

    2009-01-01

    Full Text Available Interphase chromosomes have been shown to occupy discrete regions of the nucleus denominated chromosome territories (CTs, their active genes being preferentially positioned on the surfaces of these CTs, where they are accessible to transcriptional machinery. By means of FISH (Fluorescence in situ Hybridization, we analyzed the CCND1 and HER-2/neu gene positions within the CTs and their relationship with gene amplification and protein over-expression in esophageal and gastric cancers. The CCND1 and HER-2/Neu genes were more often positioned at the periphery (mean frequency of 60%-83% of the CTs in tumor tissues of the esophagus and stomach. Moreover, this positioning revealed no association with either gene amplification or the protein over-expression status of these genes, although, in esophageal carcinoma, Kappa statistics showed a moderate agreement between amplification of the CCND1 gene (Kappa = 0.400 and its location within the CT, as well as with over-expression of the corresponding protein (Kappa = 0.444. Thus, our results suggest that gene positioning in interphase chromosomes does not follow a definitive pattern neither does it depend only on gene transcriptional activity. Apparently, this positioning could be both gene- and tissue-specific, and depends on other factors acting together, such as dense-gene, chromosome size, chromatin structure, and the level and stability of its expression.

  9. Changes in the phenotype of human small cell lung cancer cell lines after transfection and expression of the c-myc proto-oncogene.

    Science.gov (United States)

    Johnson, B E; Battey, J; Linnoila, I; Becker, K L; Makuch, R W; Snider, R H; Carney, D N; Minna, J D

    1986-01-01

    Small cell lung cancer growing in cell culture possesses biologic properties that allow classification into two categories: classic and variant. Compared with classic small cell lung cancer cell lines, variant lines have altered large cell morphology, shorter doubling times, higher cloning efficiencies in soft agarose, and very low levels of L dopa decarboxylase production and bombesin-like immunoreactivity. C-myc is amplified and expressed in some small cell lung cancer cell lines and all c-myc amplified lines studied to date display the variant phenotype. To investigate if c-myc amplification and expression is responsible for the variant phenotype, a normal human c-myc gene was transfected into a cloned classic small cell lung cancer cell line not amplified for or expressing detectable c-myc messenger RNA (mRNA). Clones were isolated with one to six copies of c-myc stably integrated into DNA that expressed c-myc mRNA. In addition, one clone with an integrated neo gene but a deleted c-myc gene was isolated and in this case c-myc was not expressed. C-myc expression in transfected clones was associated with altered large cell morphology, a shorter doubling time, and increased cloning efficiency, but no difference in L dopa decarboxylase levels and bombesin-like immunoreactivity. We conclude increased c-myc expression observed here in transfected clones correlates with some of the phenotypic properties distinguishing c-myc amplified variants from unamplified classic small cell lung cancer lines. Images PMID:3016030

  10. Detection of gene amplification in MYCN, C-MYC, MYCL1, ERBB2, EGFR, AKT2, and human papilloma virus in samples from cervical smear normal cytology, intraepithelial cervical neoplasia (CIN I, II, III, and cervical cancer

    Directory of Open Access Journals (Sweden)

    Dabeiba Adriana García

    2011-06-01

    Full Text Available Introducción: El cáncer cervical es el segundo cáncer más importante en mujeres a nivel mundial y es la segunda causa de muerte por cáncer en mujeres. Se ha demostrado que el proceso de carcinogénesis cervical presenta componentes tanto genéticos como epigenéticos y medio ambientales. En la actualidad, hay gran interés en la búsqueda de marcadores moleculares asociados con la progresión de esta enfermedad, uno de los posibles mecanismos y que además está poco estudiado en cáncer cervical es la amplificación génica de algunos oncogenes como la familia MYC, EGFR y AKT entre otros. Objetivos: Detectar la amplificación génica de MYCN, C-MYC, MYCL1, ERBB2, EGFR y AKT2 además de la presencia del virus de papiloma humano en cepillados cervicales en mujeres con citología normal o con neoplasia intraepitelial cervical (NIC I, II y III o con cáncer cervical. Métodos: Se genotipificó mediante reverse line blot (RLB el virus de papiloma humano (VPH y se determinó el estado de amplificación génica de los genes mencionados mediante PCR en tiempo real utilizando sondas taqman. Resultados: El VPH se encontró presente en 4% de las pacientes con citología normal, en 48% en NIC I, 63.6% en NIC II, 64% en NIC III y 70.8% en cáncer cervical. Los genes MYCN, MYCL1 y ERBB2 mostraron mayor amplificación en lesiones de alto grado y cáncer con diferencias estadísticamente significativas  a las lesiones de bajo grado y citología normal, en 39.1%, 34.7% y 30.4% respectivamente. Además, se encontraron amplificados los genes C-MYC, EGFR y AKT2, en muestras de pacientes con cáncer cervical, en 12%, 18% y 13% respectivamente. Sin embargo, no se observaron diferencias estadísticamente significativas con respecto a las lesiones de alto y bajo grado y citología normal. Conclusión: En las lesiones de alto grado como en cáncer cervical, se encuentra mayor prevalencia del virus al igual que se detectan mayor cantidad de alteraciones gen

  11. Cooperation of Gata3, c-Myc and Notch in malignant transformation of double positive thymocytes.

    Science.gov (United States)

    van Hamburg, Jan Piet; de Bruijn, Marjolein J W; Dingjan, Gemma M; Beverloo, H Berna; Diepstraten, Hans; Ling, Kam-Wing; Hendriks, Rudi W

    2008-06-01

    Gata transcription factors are critical regulators of proliferation and differentiation implicated in various human cancers, but specific genes activated by Gata proteins remain to be identified. We previously reported that enforced expression of Gata3 during T cell development in CD2-Gata3 transgenic mice induced CD4(+)CD8(+) double-positive (DP) T cell lymphoma. Here, we show that the presence of the DO11.10 T-cell receptor transgene, which directs DP cells towards the CD4 lineage, resulted in enhanced lymphoma development and a dramatic increase in thymocyte cell size in CD2-Gata3 transgenic mice. CD2-Gata3 DP cells expressed high levels of the proto-oncogene c-Myc but the Notch1 signaling pathway, which is known to induce c-Myc, was not activated. Gene expression profiling showed that in CD2-Gata3 lymphoma cells transcription of c-Myc and its target genes was further increased. A substantial fraction of CD2-Gata3 lymphomas had trisomy of chromosome 15, leading to an increased c-Myc gene dose. Interestingly, most lymphomas showed high expression of the Notch targets Deltex1 and Hes1, often due to activating Notch1 PEST domain mutations. Therefore, we conclude that enforced Gata3 expression converts DP thymocytes into a pre-malignant state, characterized by high c-Myc expression, whereby subsequent induction of Notch1 signaling cooperates to establish malignant transformation. The finding that Gata3 regulates c-Myc expression levels, in a direct or indirect fashion, may explain the parallel phenotypes of mice with overexpression or deficiency of either of the two transcription factors.

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

    Directory of Open Access Journals (Sweden)

    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.

  13. OCT4 increases BIRC5 and CCND1 expression and promotes cancer progression in hepatocellular carcinoma

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    Cao Lu

    2013-02-01

    Full Text Available Abstract Background OCT4 and BIRC5 are preferentially expressed in human cancer cells and mediate cancer cell survival and tumor maintenance. However, the molecular mechanism that regulates OCT4 and BIRC5 expression is not well characterized. Methods By manipulating OCT4 and BIRC5 expression in hepatocellular carcinoma (HCC cell lines, the regulatory mechanism of OCT4 on BIRC5 and CCND1 were investigated. Results Increasing or decreasing OCT4 expression could enhance or suppress BIRC5 expression, respectively, by regulating the activity of BIRC5 promoter. Because there is no binding site for OCT4 within BIRC5 promoter, the effect of OCT4 on BIRC5 promoter is indirect. An octamer motif for OCT4 in the CCND1 promoter has directly and partly participated in the regulation of CCND1 promoter activity, suggesting that OCT4 also could upregulated the expression of CCND1. Co-suppression of OCT4 and BIRC5 induced cancer cell apoptosis and cell cycle arrest, thereby efficiently inhibiting the proliferative activity of cancer cells and suppressing the growth of HCC xenogrfts in nude mice. Conclusion OCT4 can upregulate BIRC5 and CCND1 expression by increasing their promoter activity. These factors collusively promotes HCC cell proliferation, and co-suppression of OCT4 and BIRC5 is potentially beneficial for HCC treatment.

  14. Expression of c-myc during differentiation of the human teratocarcinoma cell line Tera-2.

    Science.gov (United States)

    Schofield, P N; Engstrom, W; Lee, A J; Biddle, C; Graham, C F

    1987-08-01

    The quantity of c-myc mRNA was measured during the retinoic-acid-induced differentiation of the pluripotent human teratoma cell line, Tera-2 cl. 13. As the cells were exposed to retinoic acid for longer periods of time the duration of the cell cycle progressively increased (measured by the rate of S phase entry) until the cells were effectively quiescent and expressed characteristic differentiation markers. Under these circumstances steady-state levels of c-myc expression increased by up to 1.6-fold with respect to rapidly growing undifferentiated cells. Southern blot analysis of the c-myc genes in Tera-2 indicated no major rearrangement or amplification in the cell line.

  15. C-Myc negatively controls the tumor suppressor PTEN by upregulating miR-26a in glioblastoma multiforme cells

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Pin; Nie, Quanmin; Lan, Jin; Ge, Jianwei [Department of Neurosurgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127 (China); Qiu, Yongming, E-mail: qiuzhoub@hotmail.com [Department of Neurosurgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127 (China); Shanghai Institute of Head Trauma, Shanghai 200127 (China); Mao, Qing, E-mail: maoq@netease.com [Department of Neurosurgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127 (China); Shanghai Institute of Head Trauma, Shanghai 200127 (China)

    2013-11-08

    Highlights: •The c-Myc oncogene directly upregulates miR-26a expression in GBM cells. •ChIP assays demonstrate that c-Myc interacts with the miR-26a promoter. •Luciferase reporter assays show that PTEN is a specific target of miR-26a. •C-Myc–miR-26a suppression of PTEN may regulate the PTEN/AKT pathway. •Overexpression of c-Myc enhances the proliferative capacity of GBM cells. -- Abstract: The c-Myc oncogene is amplified in many tumor types. It is an important regulator of cell proliferation and has been linked to altered miRNA expression, suggesting that c-Myc-regulated miRNAs might contribute to tumor progression. Although miR-26a has been reported to be upregulated in glioblastoma multiforme (GBM), the mechanism has not been established. We have shown that ectopic expression of miR-26a influenced cell proliferation by targeting PTEN, a tumor suppressor gene that is inactivated in many common malignancies, including GBM. Our findings suggest that c-Myc modulates genes associated with oncogenesis in GBM through deregulation of miRNAs via the c-Myc–miR-26a–PTEN signaling pathway. This may be of clinical relevance.

  16. Interaction of c-Myc with the pRb-related protein p107 results in inhibition of c-Myc-mediated transactivation

    NARCIS (Netherlands)

    Beijersbergen, R.L.; Hijmans, E.M.; Zhu, L.; Bernards, R.A.

    1994-01-01

    The product of the c-myc proto-oncogene, c-Myc, is a sequence-specific DNA binding protein with an Nterminal transactivation domain and a C-terminal DNA binding domain. Several lines of evidence indicate that c-Myc activity is essential for normal cell cycle progression. Since the abundance of c-Myc

  17. Specific regulation of mRNA cap methylation by the c-Myc and E2F1 transcription factors

    Science.gov (United States)

    Cole, Michael D.; Cowling, Victoria H.

    2009-01-01

    Methylation of the mRNA 5′ guanosine cap is essential for efficient gene expression. The 5′methyl cap binds to eIF4E, which is the first step in the recruitment of mRNA to the 40S ribosomal subunit. To investigate whether mRNA cap methylation is regulated in a gene-specific manner, we established a method to detect the relative level of cap methylation on specific mRNAs. We found that two transcription factors, c-Myc and E2F1, induce cap methylation of their transcriptional target genes, and therefore, c-Myc and E2F1 upregulate gene expression by simultaneously inducing transcription and promoting translation. c-Myc-induced cap methylation is greater than transcriptional induction for the majority of its target genes, indicating that this is a major mechanism by which Myc regulates gene expression. PMID:19137018

  18. Transient in utero knockout (TIUKO of C-MYC affects late lung and intestinal development in the mouse

    Directory of Open Access Journals (Sweden)

    Zhou Pengbo

    2004-04-01

    Full Text Available Abstract Background Developmentally important genes often result in early lethality in knockout animals. Thus, the direct role of genes in late gestation organogenesis cannot be assessed directly. In utero delivery of transgenes was shown previously to result in high efficiency transfer to pulmonary and intestinal epithelial stem cells. Thus, this technology can be used to evaluate late gestation development. Results In utero gene transfer was used to transfer adenovirus with either an antisense c-myc or a C-MYC ubiquitin targeting protein to knockout out c-myc expression in late gestation lung and intestines. Using either antisense or ubiquitin mediated knockout of C-MYC levels in late gestation resulted in similar effects. Decreased complexity was observed in both intestines and lungs. Stunted growth of villi was evident in the intestines. In the lung, hypoplastic lungs with disrupted aveolarization were observed. Conclusions These data demonstrated that C-MYC was required for cell expansion and complexity in late gestation lung and intestinal development. In addition they demonstrate that transient in utero knockout of proteins may be used to determine the role of developmentally important genes in the lungs and intestines.

  19. Berberine inhibits cyclin D1 expression via suppressed binding of AP-1 transcription factors to CCND1 AP-1 motif

    Institute of Scientific and Technical Information of China (English)

    Ye LUO; Yu HAO; Tai-ping SHI; Wei-wei DENG; Na LI

    2008-01-01

    Aim: To verify the suppressive effect of berberine on the proliferation of the human pulmonary giant cell carcinoma cell line PG and to demonstrate the mecha-nisms behind the antitumoral effects of berberine. Methods: The proliferative effects of PG cells were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide colorimetry. The cell cycle was examined by flow cytometry. The expression level of cyclin D1 was detected by RT-PCR. The activities of the activating protein-1 (AP-1) and NF-κB signaling pathways related to cyclin D1 were examined by luciferase assay. The cytoplasmic level of c-Jun was detected by Western blot analysis. An electrophoretic mobility shift assay was used to examiae the binding of transcription factors to the cyclin D1 gene (CCNDl) AP-1 motif. Results: The results showed that the proliferation of PG cells treated with different concentrations (10, 20, and 40 μg/mL) of berberine for 24 and 48 h was suppressed significantly compared to the control group. After treatment with berberine, the proportion of PG cells at the G0/G1 phase increased, while cells at the S and G2/M phases decreased. Berberine could inhibit the expression of cyclin D1 in PG cells. Berberine inhibited the activity of the AP-1 signaling pathway, but had no significant effect on the NF-κB signaling pathway. Berberine suppressed the expression of c-Jun and decreased the binding of tran-scription factors to the CCND1 AP-1 motif. Conclusion: Berberine suppresses the activity of the AP-1 signaling pathway and decreases the binding of transcrip-tion factors to the CCND1 AP-1 motif. This is one of the important mechanisms behind the antitumoral effects of berberine as a regulator of cyclin D1.

  20. 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.

  1. Chromatin dynamics at the hTERT promoter during transcriptional activation and repression by c-Myc and Mnt in Xenopus leavis oocytes.

    Science.gov (United States)

    Wahlström, Therese; Belikov, Sergey; Arsenian Henriksson, Marie

    2013-12-10

    The transcription factors c-Myc and Mnt regulate gene expression through dimerization with Max and binding to E-boxes in target genes. While c-Myc activates gene expression via recruitment of histone modifying complexes, Mnt acts as a transcriptional repressor. Here, we used the Xenopus leavis oocyte system to address the effect of c-Myc and Mnt on transcription and chromatin remodeling over the E-box region in the human telomerase reverse transcriptase (hTERT) promoter. As expected we found elevated and decreased levels of hTERT transcription upon exogenously expressed c-Myc/Max and Mnt/Max, respectively. In addition, we confirmed binding of these heterodimers to both E-boxes already enriched with H3K9ac and H4K16ac. These chromatin marks were further enhanced upon c-Myc/Max binding followed by increased DNA accessibility in the E-box region. In contrast, Mnt/Max inhibited Myc-induced transcription and mediated repression through complete chromatin condensation and deacetylation of H3K9 and H4K16 across the E-box region. Importantly, Mnt was able to counteract c-Myc mediated activation even when expressed at low levels, suggesting Mnt to act as a strong repressor by closing the chromatin structure. Collectively our data demonstrate that the balance between c-Myc and Mnt activity determines the transcriptional outcome of the hTERT promoter by modulation of the chromatin architecture.

  2. The c-myc coding DNA sequences of cyprinids (Teleostei: Cypriniformes): Implications for phylogeny

    Institute of Scientific and Technical Information of China (English)

    KONG XiangHui; WANG XuZhen; GAN XiaoNi; HE ShunPing

    2007-01-01

    The family Cyprinidae is one of the largest fish families in the world, which is widely distributed in East Asian, with obvious difference in characteristic size among species. The phylogenetic analysis of cyprinid taxa based on the functionally important genes can help to understand the speciation and functional divergence of the Cyprinidae. The c-myc gene is an important gene regulating individual growth.In the present study, the sequence variations of the cyprinid c-myc gene and their phylogenetic significance were analyzed. The 41 complete sequences of the c-myc gene were obtained from cyprinids and outgroups through PCR amplification and clone. The coding DNA sequences of the c-myc gene were used to infer molecular phylogenetic relationships within the Cyprinidae. Myxocyprinus asiaticus (Catostomidae), Misgurnus anguillicaudatus (Cobitidae) and Hemimyzon sinensis (Homalopteridae)were assigned to the outgroup taxa. Phylogenetic analyses using maximum parsimony (MP), maximum likelihood (ML), and Bayesian retrieved similar topology. Within the Cyprinidae, Leuciscini and Barbini formed the monophyletic lineage respectively with high nodal supports. Leuciscini comprises Xenocyprinae, Cultrinae, East Asian species of Leuciscinae and Danioninae, Gobioninae and Acheilognathinae, and Barbini contains Schizothoracinae, Barbinae, Cyprininae and Labeoninae. Danio rerio, D.myersi and Rasbora trilineata were supposed to separate from Leuciscinae and Barbini and to form another lineage. The positions of some Danioninae species were still unresolved. Analyses of both amino acid variation with parsimony information and two high variation regions indicated that there is no correlation between variations of single amino acid or high variation regions and characteristic size of cyprinids. In addition, the species with smaller size were usually found to be basal within clades in the tree, which might be the results of the adaptation to the primitive ecology and survival pressure.

  3. Cadmium Activates Multiple Signaling Pathways That Coordinately Stimulate Akt Activity to Enhance c-Myc mRNA Stability.

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    Jia-Shiuan Tsai

    Full Text Available Cadmium is a known environmental carcinogen. Exposure of Cd leads to the activation of several proto-oncogenes in cells. We investigated here the mechanism of c-Myc expression in hepatic cells under Cd treatment. The c-Myc protein and mRNA levels increased in dose- and time-dependent manners in HepG2 cells with Cd treatment. This increase was due to an increase in c-Myc mRNA stability. To explore the mechanism involved in enhancing the mRNA stability, several cellular signaling factors that evoked by Cd treatment were analyzed. PI3K, p38, ERK and JNK were activated by Cd. However, ERK did not participate in the Cd-induced c-Myc expression. Further analysis revealed that mTORC2 was a downstream factor of p38. PI3K, JNK and mTORC2 coordinately activated Akt. Akt was phosphorylated at Thr450 in the untreated cells. Cd treatment led to additional phosphorylation at Thr308 and Ser473. Blocking any of the three signaling factors resulted in the reduction of phosphorylation level at all three Akt sites. The activated Akt phosphorylated Foxo1 and allowed the modified protein to translocate into the cytoplasm. We conclude that Cd-induced accumulation of c-Myc requires the activation of several signaling pathways. The signals act coordinately for Akt activation and drive the Foxo1 from the nucleus to the cytoplasm. Reduction of Foxo1 in the nucleus reduces the transcription of its target genes that may affect c-Myc mRNA stability, resulting in a higher accumulation of the c-Myc proteins.

  4. Depressive Effect of the Antisense Oligonucleotides of C-myc and PCNA on the Proliferation of VSMC

    Institute of Scientific and Technical Information of China (English)

    Qingxian Li; Yanfu Wang; Yuhua Liao; Huiling Zhang; Yanying Jiang

    2007-01-01

    To study the depressive effect of the antisense oligonuceotides (ASODN) of c-myc and proliferating cell nuclear antigen (PCNA) on the proliferation of VSMC.Methods Taking the VSMC obtained from rat aorta thoracalis cultured 4 ~ 8 generation as research object.The objects were divided into three groups to carry out control study:control group,PCNA ASODN group and c-myc ASODN group.The ASODNs' working concentration all were 1:50.The depressive effect of ASODN on VSMC proliferation was investigated by cell counting,MTT and 3H-TdR incorporation assay;PCNA and c-myc expression were detected by immunohistochemical method after transferring PCNA successfully;the corresponding gene was inhibited obviously;compared with control group ( P < 0.05 ).Conclusions PCNA and c-myc might play a considerable role in the VSMC proliferation process.The corresponding gene could be depressed successfully after transferring PCNA and c-myc ASODN into VSMC,and then the proliferation of VSMC was slowed down.This study presented a beneficial proposal and theoretical fundament for atherosclerotic treatment.

  5. Anchoring of c-myc on nuclear matrix proteins in process of mouse thymic T lymphocyte proliferation induced by ConA

    Institute of Scientific and Technical Information of China (English)

    曾丛梅; 蔡树涛; 周凤兰; 张锦珠; 王平

    1996-01-01

    Isolation and characteriation of functional nudear matrix proteins involved in DNA anchoring and gene expression is one of the major subjects of current nudear matrix research. Southwestern blotting (DNA-protein hybridization) was applied to studying the anchoring of c-myc on the nudear matrix proteins in mouse thymic T lymphocytes. The results showed that c-myc bound to the lamin, p34 and p36 nudear matrix proteins specifically. In the process of mouse thymic PNA T lymphocytes proliferation induced by ConA, the anchoring of c-myc on p34 and p36 nudear matrix proteins changed dynamically.

  6. Long-range oncogenic activation of Igh-c-myc translocations by the Igh 3' regulatory region.

    Science.gov (United States)

    Gostissa, Monica; Yan, Catherine T; Bianco, Julia M; Cogné, Michel; Pinaud, Eric; Alt, Frederick W

    2009-12-10

    B-cell malignancies, such as human Burkitt's lymphoma, often contain translocations that link c-myc or other proto-oncogenes to the immunoglobulin heavy chain locus (IgH, encoded by Igh). The nature of elements that activate oncogenes within such translocations has been a long-standing question. Translocations within Igh involve DNA double-strand breaks initiated either by the RAG1/2 endonuclease during variable, diversity and joining gene segment (V(D)J) recombination, or by activation-induced cytidine deaminase (AID, also known as AICDA) during class switch recombination (CSR). V(D)J recombination in progenitor B (pro-B) cells assembles Igh variable region exons upstream of mu constant region (Cmu) exons, which are the first of several sets of C(H) exons ('C(H) genes') within a C(H) locus that span several hundred kilobases (kb). In mature B cells, CSR deletes Cmu and replaces it with a downstream C(H) gene. An intronic enhancer (iEmu) between the variable region exons and Cmu promotes V(D)J recombination in developing B cells. Furthermore, the Igh 3' regulatory region (Igh3'RR) lies downstream of the C(H) locus and modulates CSR by long-range transcriptional enhancement of C(H) genes. Transgenic mice bearing iEmu or Igh3'RR sequences fused to c-myc are predisposed to B lymphomas, demonstrating that such elements can confer oncogenic c-myc expression. However, in many B-cell lymphomas, Igh-c-myc translocations delete iEmu and place c-myc up to 200 kb upstream of the Igh3'RR. Here we address the oncogenic role of the Igh3'RR by inactivating it in two distinct mouse models for B-cell lymphoma with Igh-c-myc translocations. We show that the Igh3'RR is dispensable for pro-B-cell lymphomas with V(D)J recombination-initiated translocations, but is required for peripheral B-cell lymphomas with CSR-associated translocations. As the Igh3'RR is not required for CSR-associated Igh breaks or Igh-c-myc translocations in peripheral B-cell lymphoma progenitors, we conclude that

  7. SIRT1 Limits Adipocyte Hyperplasia through c-Myc Inhibition.

    Science.gov (United States)

    Abdesselem, Houari; Madani, Aisha; Hani, Ahmad; Al-Noubi, Muna; Goswami, Neha; Ben Hamidane, Hisham; Billing, Anja M; Pasquier, Jennifer; Bonkowski, Michael S; Halabi, Najeeb; Dalloul, Rajaa; Sheriff, Mohamed Z; Mesaeli, Nasrin; ElRayess, Mohamed; Sinclair, David A; Graumann, Johannes; Mazloum, Nayef A

    2016-01-29

    The expansion of fat mass in the obese state is due to increased adipocyte hypertrophy and hyperplasia. The molecular mechanism that drives adipocyte hyperplasia remains unknown. The NAD(+)-dependent protein deacetylase sirtuin 1 (SIRT1), a key regulator of mammalian metabolism, maintains proper metabolic functions in many tissues, counteracting obesity. Here we report that differentiated adipocytes are hyperplastic when SIRT1 is knocked down stably in mouse 3T3-L1 preadipocytes. This phenotype is associated with dysregulated adipocyte metabolism and enhanced inflammation. We also demonstrate that SIRT1 is a key regulator of proliferation in preadipocytes. Quantitative proteomics reveal that the c-Myc pathway is altered to drive enhanced proliferation in SIRT1-silenced 3T3-L1 cells. Moreover, c-Myc is hyperacetylated, levels of p27 are reduced, and cyclin-dependent kinase 2 (CDK2) is activated upon SIRT1 reduction. Remarkably, differentiating SIRT1-silenced preadipocytes exhibit enhanced mitotic clonal expansion accompanied by reduced levels of p27 as well as elevated levels of CCAAT/enhancer-binding protein β (C/EBPβ) and c-Myc, which is also hyperacetylated. c-Myc activation and enhanced proliferation phenotype are also found to be SIRT1-dependent in proliferating mouse embryonic fibroblasts and differentiating human SW872 preadipocytes. Reducing both SIRT1 and c-Myc expression in 3T3-L1 cells simultaneously does not induce the adipocyte hyperplasia phenotype, confirming that SIRT1 controls adipocyte hyperplasia through c-Myc regulation. A better understanding of the molecular mechanisms of adipocyte hyperplasia will open new avenues toward understanding obesity.

  8. c-Myc Transforms Human Mammary Epithelial Cells through Repression of the Wnt Inhibitors DKK1 and SFRP1▿ †

    Science.gov (United States)

    Cowling, Victoria H.; D'Cruz, Celina M.; Chodosh, Lewis A.; Cole, Michael D.

    2007-01-01

    c-myc is frequently amplified in breast cancer; however, the mechanism of myc-induced mammary epithelial cell transformation has not been defined. We show that c-Myc induces a profound morphological transformation in human mammary epithelial cells and anchorage-independent growth. c-Myc suppresses the Wnt inhibitors DKK1 and SFRP1, and derepression of DKK1 or SFRP1 reduces Myc-dependent transforming activity. Myc-dependent repression of DKK1 and SFRP1 is accompanied by Wnt target gene activation and endogenous T-cell factor activity. Myc-induced mouse mammary tumors have repressed SFRP1 and increased expression of Wnt target genes. DKK1 and SFRP1 inhibit the transformed phenotype of breast cancer cell lines, and DKK1 inhibits tumor formation. We propose a positive feedback loop for activation of the c-myc and Wnt pathways in breast cancer. PMID:17485441

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

    Science.gov (United States)

    Montagne, Martin; Beaudoin, Nicolas; Fortin, David; Lavoie, Christine L; Klinck, Roscoe; Lavigne, Pierre

    2012-01-01

    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.

  10. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1987-07-24

    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/sup 0/C resulted in at least a 100-fold induction of recombinant c-myc mRNA. When cells were shifted back to 37/sup 0/C, within 1 to 4 hours, this RNA was translated into protein to yield about 250 ..mu..g per 10/sup 9/ cells. Cells died a few hours later, suggesting that high concentrations of intracellular c-myc are cytotoxic. 47 refs., 5 figs.

  12. Prognostic Importance of Cell Cycle Regulators Cyclin D1 (CCND1) and Cyclin-Dependent Kinase Inhibitor 1B (CDKN1B/p27) in Sporadic Gastric Cancers

    Science.gov (United States)

    Minarikova, Petra; Halkova, Tereza; Belsanova, Barbora; Tuckova, Inna; Belina, Frantisek; Dusek, Ladislav; Zavoral, Miroslav

    2016-01-01

    Background. Gastric cancer is known for a notable variety in the course of the disease. Clinical factors, such as tumor stage, grade, and localization, are key in patient survival. It is expected that molecular factors such as somatic mutations and gene amplifications are also underlying tumor biological behavior and may serve as factors for prognosis estimation. Aim. The purpose of this study was to examine gene amplifications from a panel of genes to uncover potential prognostic marker candidates. Methods. A panel of gene amplifications including 71 genes was tested by multiplex ligation-dependent probe amplification (MLPA) technique in 76 gastric cancer samples from a Caucasian population. The correlation of gene amplification status with patient survival was determined by the Kaplan-Meier method. Results. The amplification of two cell cycle regulators, CCND1 and CDKN1B, was identified to have a negative prognostic role. The medial survival of patients with gastric cancer displaying amplification compared to patients without amplification was 192 versus 725 days for CCND1 (P = 0.0012) and 165 versus 611 days for CDKN1B (P = 0.0098). Conclusion. Gene amplifications of CCND1 and CDKN1B are potential candidates to serve as prognostic markers for the stratification of patients based on the estimate of survival in the management of gastric cancer patients.

  13. Analysis of secretome changes uncovers an autocrine/paracrine component in the modulation of cell proliferation and motility by c-Myc.

    Science.gov (United States)

    Pocsfalvi, Gabriella; Votta, Giuseppina; De Vincenzo, Anna; Fiume, Immacolata; Raj, Delfin Albert Amal; Marra, Giancarlo; Stoppelli, Maria Patrizia; Iaccarino, Ingram

    2011-12-02

    Proteins secreted by cancer cells are a major component of tumor microenvironment. However, little is known on the impact of single oncogenic lesions on the expression of secreted proteins at early stages of tumor development. Because c-Myc overexpression is among the most frequent alterations in cancer, here we investigated the effect of sustained c-Myc expression on the secretome of a nontransformed human epithelial cell line (hT-RPE). By using a quantitative proteomic approach, we have identified 125 proteins in conditioned media of hT-RPE/MycER cells upon c-Myc induction. Analysis of the 49 proteins significantly down-regulated by c-Myc revealed a marked enrichment of factors associated with growth inhibition and cellular senescence. Accordingly, media conditioned by hT-RPE cells expressing c-Myc show an increased ability to sustain hT-RPE cellular proliferation/viability. We also find a marked down-regulation of several structural and regulatory components of the extracellular matrix (ECM), which correlates with an increased chemotactic potency of the conditioned media toward fibroblasts, a major cellular component of tumor stroma. In accordance with these data, the expression of the majority of the genes encoding proteins down-regulated in hT-RPE was significantly reduced also in colorectal adenomatous polyps, early tumors in which c-Myc is invariably overexpressed. These findings help to elucidate the significance of c-Myc overexpression at early stages of tumor development and uncover a remarkable autocrine/paracrine component in the ability of c-Myc to stimulate proliferation, sustain tumor maintenance, and modulate cell migration.

  14. 聚乙烯亚胺介导BmkCT基因抑制C6胶质瘤细胞C-Myc、VEGF表达%Expression of Polyethyleneimine-mediated Bmk CT Gene Inhibitation to VEGF and C-Myc in C6 Glioma Cells

    Institute of Scientific and Technical Information of China (English)

    张亚涛; 范丽娜; 温春丽; 胡风云

    2016-01-01

    目的:应用阳离子聚合物聚乙烯亚胺(polyethyleneimine,PEI)介导东亚钳蝎氯离子通道毒素( Buthus martensii Karsch Chlorotoxin-like Toxin,Bmk CT)基因转染 C6胶质瘤细胞,观察其对 C6细胞内 C-Myc、VEGF 表达的影响。方法:将 PEI 分别和 pEGFP-N1-Bmk CT、pEGFP-N1质粒混合,获得 PEI / pEGFP-N1-Bmk CT 和 PEI / pEG-FP-N1两种复合物,将其转染 C6细胞,MTS 法观察细胞增殖和存活活力,48 h后通过 Western-blot 方法检测 C-Myc、VEGF 蛋白表达水平。结果:PEI / pEGFP-N1-Bmk CT 转染 C6细胞48 h后较 PEI / pEGFP-N1能够显著抑制C6细胞增殖和存活活力,同时抑制 C-Myc、VEGF 蛋白表达。结论:PEI / pEGFP-N1-Bmk CT 转染 C6细胞可能通过抑制 C-Myc、VEGF 表达进而抑制 C6细胞增殖和血管生成。%Objective:To investigate the effects of PEI(polyethyleneimine)-mediated Bmk CT(Buthus martensii Karsch Chlorotoxin-like Toxin),Bmk CT gene transfection on the expression levels of C-Myc and VEGF of C6 glioma cells. Methods:pEGFP-N1 and pEGFP-N1-BmK CT were combined with PEI to form the composites,PEI/ pEGFP-N1-Bmk CT and PEI/ pEGFP-N1,which were used to transfect C6 glioma cells. Then,MTS test was performed to investigate the proliferation and viability of the transfected cells. After 48 hours the expression of C-Myc and VEGF proteins were de-tected by Western-bloting. Results:The proliferation of C6 glioma cells in the pEGFP-N1-Bmk CT group was significant-ly inhibited,while the expression levels of C-Myc and VEGF were lower than pEGFP-N1 group after the transfection. Conclusion:PEI/ pEGFP-N1-Bmk CT may suppress the angiogenesis and the proliferation of C6 glioma cells through in-hibiting the expression of C-Myc and VEGF.

  15. Deubiquitinating c-Myc: USP36 steps up in the nucleolus.

    Science.gov (United States)

    Sun, Xiao-Xin; Sears, Rosalie C; Dai, Mu-Shui

    2015-01-01

    Ubiquitination plays a key and complex role in the regulation of c-Myc stability, transactivation, and oncogenic activity. c-Myc is ubiquitinated by a number of ubiquitin ligases (E3s), such as SCF(Fbw7) and SCF(Skp2). Depending on the E3s, ubiquitination can either positively or negatively regulate c-Myc levels and activity. Meanwhile, c-Myc ubiquitination can be reversed by deubiquitination. An early study showed that USP28 deubiquitinates c-Myc via interacting with Fbw7α whereas a recent study reveals that USP37 deubiquitinates c-Myc independently of Fbw7 and c-Myc phosphorylation. Consequently, both USP28 and USP37 stabilize c-Myc and enhance its activity. We recently found the nucleolar USP36 as a novel c-Myc deubiquitinase that controls the end-point of c-Myc degradation pathway in the nucleolus. Here we briefly review the current understanding of ubiquitination and deubiquitination regulation of c-Myc and further discuss the USP36-c-Myc regulatory pathway.

  16. 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...

  17. Lack of cyclin-dependent kinase 4 inhibits c-myc tumorigenic activities in epithelial tissues.

    Science.gov (United States)

    Miliani de Marval, Paula L; Macias, Everardo; Rounbehler, Robert; Sicinski, Piotr; Kiyokawa, Hiroaki; Johnson, David G; Conti, Claudio J; Rodriguez-Puebla, Marcelo L

    2004-09-01

    The proto-oncogene c-myc encodes a transcription factor that is implicated in the regulation of cellular proliferation, differentiation, and apoptosis and that has also been found to be deregulated in several forms of human and experimental tumors. We have shown that forced expression of c-myc in epithelial tissues of transgenic mice (K5-Myc) resulted in keratinocyte hyperproliferation and the development of spontaneous tumors in the skin and oral cavity. Although a number of genes involved in cancer development are regulated by c-myc, the actual mechanisms leading to Myc-induced neoplasia are not known. Among the genes regulated by Myc is the cyclin-dependent kinase 4 (CDK4) gene. Interestingly, previous studies from our laboratory showed that the overexpression of CDK4 led to keratinocyte hyperproliferation, although no spontaneous tumor development was observed. Thus, we tested the hypothesis that CDK4 may be one of the critical downstream genes involved in Myc carcinogenesis. Our results showed that CDK4 inhibition in K5-Myc transgenic mice resulted in the complete inhibition of tumor development, suggesting that CDK4 is a critical mediator of tumor formation induced by deregulated Myc. Furthermore, a lack of CDK4 expression resulted in marked decreases in epidermal thickness and keratinocyte proliferation compared to the results obtained for K5-Myc littermates. Biochemical analysis of the K5-Myc epidermis showed that CDK4 mediates the proliferative activities of Myc by sequestering p21Cip1 and p27Kip1 and thereby indirectly activating CDK2 kinase activity. These results show that CDK4 mediates the proliferative and oncogenic activities of Myc in vivo through a mechanism that involves the sequestration of specific CDK inhibitors.

  18. c-Myc regulates proliferation and Fgf10 expression in airway smooth muscle after airway epithelial injury in mouse.

    Directory of Open Access Journals (Sweden)

    Thomas Volckaert

    Full Text Available During lung development, Fibroblast growth factor 10 (Fgf10, which is expressed in the distal mesenchyme and regulated by Wnt signaling, acts on the distal epithelial progenitors to maintain them and prevent them from differentiating into proximal (airway epithelial cells. Fgf10-expressing cells in the distal mesenchyme are progenitors for parabronchial smooth muscle cells (PSMCs. After naphthalene, ozone or bleomycin-induced airway epithelial injury, surviving epithelial cells secrete Wnt7b which then activates the PSMC niche to induce Fgf10 expression. This Fgf10 secreted by the niche then acts on a subset of Clara stem cells to break quiescence, induce proliferation and initiate epithelial repair. Here we show that conditional deletion of the Wnt target gene c-Myc from the lung mesenchyme during development does not affect proper epithelial or mesenchymal differentiation. However, in the adult lung we show that after naphthalene-mediated airway epithelial injury c-Myc is important for the activation of the PSMC niche and as such induces proliferation and Fgf10 expression in PSMCs. Our data indicate that conditional deletion of c-Myc from PSMCs inhibits airway epithelial repair, whereas c-Myc ablation from Clara cells has no effect on airway epithelial regeneration. These findings may have important implications for understanding the misregulation of lung repair in asthma and COPD.

  19. 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.

  20. K-RAS point mutation, and amplification of C-MYC and C-ERBB2 in colon adenocarcinoma.

    Directory of Open Access Journals (Sweden)

    Tadeusz Pawełczyk

    2004-10-01

    Full Text Available The routine multidisciplinary management of colon cancer is based mainly on tumor staging, histology, grading and vascular invasion. In this approach, important individual information derived from molecular characteristics of the tumor may be missed, especially since significant heterogeneity of molecular aberrations in cancer cells has been observed, and recognition of every of relationships between them may be of value. K-RAS, C-MYC and C-ERBB2 are protooncogenes taking part in carcinogenesis and tumor progression in the colon. They influence cell proliferation, differentiation and survival. K-RAS point mutation, as well as amplification of C-MYC and C-ERBB2 were searched in 84 primary colon adenocarcinomas resected with curative intent. Multiplex polymerase-chain reaction and restriction fragment length polymorphism were performed to assess codon 12 K-RAS point mutation. Amplification of C-MYC and C-ERBB2 genes was evaluated by densitometry after agarose gel separation of the respective multiplex PCR products. No relation was found among mutated and/or amplified genes, and between searched molecular aberrations and pathoclinical features. In multivariate analysis, nodal status appeared to be the only independent prognostic indicator. In colon adenocarcinoma, codon 12 K-RAS point mutation and amplification of C-MYC and C-ERBB2 seem to occur independently in the process of tumor progression. Amplification of C-ERBB2 tends to associate with more advanced stage of disease. Concomitant occurrence of codon 12 K-RAS mutation, C-MYC and C-ERBB2 amplification was of no prognostic value in respect to survival.

  1. bcl-1, bcl-2, p53, c-myc, and lyt-10 analysis in cutaneous lymphomas.

    Science.gov (United States)

    Garatti, S A; Roscetti, E; Trecca, D; Fracchiolla, N S; Neri, A; Berti, E

    1995-01-01

    In the present study we investigated the pathogenetic role of c-myc, bcl-2, and lyt-10 oncogenes, bcl-1 locus, and p53 suppressor gene in a representative panel of cutaneous lymphomas, including 25 cases of cutaneous B cell lymphoma (CBCL) and 29 cases of cutaneous T cell lymphoma (CTCL). In our analysis four cases of CBCL were found rearranged for bcl-2 and two for the bcl-1 locus. Two cases of CTCL and one case of CBCL were found rearranged for lyt-10. No rearrangements of c-myc oncogene were found in CBCL. Analysis of p53 gene showed mutation only in one case of mycosis fungoides in tumoral stage, at codon 163 of p53 gene (TAC-->CAC; Tyr--> Asp). Our data suggest that in primary CBCL bcl-2 oncogenes and bcl-1 locus are rarely involved. Furthermore, in primary CTCL p53 gene is not affected at significant frequency. The occurrence of p53 mutation in a patient affected by mycosis fungoides in tumoral stage may represent an involvement of p53 gene in tumor progression of CTCL, a finding observed in several types of human cancer.

  2. C-Myc Protein-Protein and Protein-DNA Interactions: Targets for Therapeutic Intervention.

    Science.gov (United States)

    1996-10-01

    progression through the cell cycle (Jansen-Durr et al., 1993; Luscher and Eisenman, 1990). In the mouse, both the c- and N-Myc genes are essential for... Luscher and Eisenman, 1990), the pathways by which it does so seem to be complex. An essential insight into how c-Myc might perform these functions has...Collum and Alt, 1990; Luscher and Eisenman, 1990). Recent experiments support this idea (Amati et al., 1992; Amin et al., 1993; Gu et al., 1993; Kato et al

  3. Rabring7 Degrades c-Myc through Complex Formation with MM-1

    Science.gov (United States)

    Torii, Ayako; Tashiro, Erika; Miyazawa, Makoto; Ariga, Hiroyoshi; Iguchi-Ariga, Sanae M. M.

    2012-01-01

    We have reported that a novel c-Myc-binding protein, MM-1, repressed E-box-dependent transcription and transforming activities of c-Myc and that a mutation of A157R in MM-1, which is often observed in patients with leukemia or lymphoma, abrogated all of the repressive activities of MM-1 toward c-Myc, indicating that MM-1 is a novel tumor suppressor. MM-1 also binds to the ubiquitin-proteasome system, leading to degradation of c-Myc. In this study, we identified Rabring7, a Rab7-binding and RING finger-containing protein, as an MM-1-binding protein, and we found that Rabring7 mono-ubiquitinated MM-1 in the cytoplasm without degradation of MM-1. Rabring7 was also found to bind to c-Myc and to ubiquitinate c-Myc in a threonine 58-dependent manner. When c-Myc was co-transfected with MM-1 and Rabring7, c-Myc was degraded. Furthermore, it was found that c-Myc was stabilized in MM-1-knockdown cells even when Rabring7 was transfected and that Rabring7 was bound to and co-localized with MM-1 and c-Myc after MM-1 and Rabring7 had been translocated from the cytoplasm to the nucleus. These results suggest that Rabring7 stimulates c-Myc degradation via mono-ubiquitination of MM-1. PMID:22844532

  4. Rabring7 degrades c-Myc through complex formation with MM-1.

    Directory of Open Access Journals (Sweden)

    Rina Narita

    Full Text Available We have reported that a novel c-Myc-binding protein, MM-1, repressed E-box-dependent transcription and transforming activities of c-Myc and that a mutation of A157R in MM-1, which is often observed in patients with leukemia or lymphoma, abrogated all of the repressive activities of MM-1 toward c-Myc, indicating that MM-1 is a novel tumor suppressor. MM-1 also binds to the ubiquitin-proteasome system, leading to degradation of c-Myc. In this study, we identified Rabring7, a Rab7-binding and RING finger-containing protein, as an MM-1-binding protein, and we found that Rabring7 mono-ubiquitinated MM-1 in the cytoplasm without degradation of MM-1. Rabring7 was also found to bind to c-Myc and to ubiquitinate c-Myc in a threonine 58-dependent manner. When c-Myc was co-transfected with MM-1 and Rabring7, c-Myc was degraded. Furthermore, it was found that c-Myc was stabilized in MM-1-knockdown cells even when Rabring7 was transfected and that Rabring7 was bound to and co-localized with MM-1 and c-Myc after MM-1 and Rabring7 had been translocated from the cytoplasm to the nucleus. These results suggest that Rabring7 stimulates c-Myc degradation via mono-ubiquitination of MM-1.

  5. Effects of alcohol on c-Myc protein in the brain.

    Science.gov (United States)

    Akinyeke, Tunde; Weber, Sydney J; Davenport, April T; Baker, Erich J; Daunais, James B; Raber, Jacob

    2017-03-01

    Alcoholism is a disorder categorized by significant impairment that is directly related to persistent and extreme use of alcohol. The effects of alcoholism on c-Myc protein expression in the brain have been scarcely studied. This is the first study to investigate the role different characteristics of alcoholism have on c-Myc protein in the brain. We analyzed c-Myc protein in the hypothalamus and amygdala from five different animal models of alcohol abuse. c-Myc protein was increased following acute ethanol exposure in a mouse knockout model and following chronic ethanol consumption in vervet monkeys. We also observed increases in c-Myc protein exposure in animals that are genetically predisposed to alcohol and methamphetamine abuse. Lastly, c-Myc protein was increased in animals that were acutely exposed to methamphetamine when compared to control treated animals. These results suggest that in substance abuse c-Myc plays an important role in the brain's response.

  6. Wnt/β-catenin signaling regulates Helicoverpa armigera pupal development by up-regulating c-Myc and AP-4.

    Science.gov (United States)

    Chen, Wei; Xu, Wei-Hua

    2014-10-01

    Seasonally changing environmental conditions perceived by insect brains can be converted into hormonal signals that prompt insects to make a decision to develop or enter developmental arrest (diapause). Diapause is a complex physiological response, and many signaling pathways may participate in its regulation. However, little is known about these regulatory pathways. In this study, we cloned four genes related to the Wnt/β-catenin signaling pathway from Helicoverpa armigera, a pupal diapause species. Western blotting shows that expression of Har-Wnt1, Har-β-catenin, and Har-c-Myc are higher in non-diapause pupal brains than in diapause-destined brains. Har-Wnt1 can promote the accumulation of Har-β-catenin in the nucleus, and Har-β-catenin in turn increases the expression of Har-c-Myc. The blockage of Wnt/β-catenin signaling by the inhibitor XAV939 significantly down-regulates Har-β-catenin and Har-c-Myc expression and delays pupal development, suggesting that the Wnt/β-catenin pathway functions in insect development. Furthermore, Har-c-Myc binds to the promoter of Har-AP-4 and regulates its expression. It has been reported that Har-AP-4 activates diapause hormone (DH) expression and that DH up-regulates the growth hormone ecdysteroid for pupal development. Thus, pupal development is regulated by Wnt/β-catenin signaling through the pathway Wnt-β-catenin-c-Myc-AP-4-DH-ecdysteroid. In contrast, the down-regulation of Wnt/β-catenin signaling is likely to induce insects to enter diapause.

  7. Upregulation of c-MYC in cis through a Large Chromatin Loop Linked to a Cancer Risk-Associated Single-Nucleotide Polymorphism in Colorectal Cancer Cells▿

    Science.gov (United States)

    Wright, Jason B.; Brown, Seth J.; Cole, Michael D.

    2010-01-01

    Genome-wide association studies have mapped many single-nucleotide polymorphisms (SNPs) that are linked to cancer risk, but the mechanism by which most SNPs promote cancer remains undefined. The rs6983267 SNP at 8q24 has been associated with many cancers, yet the SNP falls 335 kb from the nearest gene, c-MYC. We show that the beta-catenin-TCF4 transcription factor complex binds preferentially to the cancer risk-associated rs6983267(G) allele in colon cancer cells. We also show that the rs6983267 SNP has enhancer-related histone marks and can form a 335-kb chromatin loop to interact with the c-MYC promoter. Finally, we show that the SNP has no effect on the efficiency of chromatin looping to the c-MYC promoter but that the cancer risk-associated SNP enhances the expression of the linked c-MYC allele. Thus, cancer risk is a direct consequence of elevated c-MYC expression from increased distal enhancer activity and not from reorganization/creation of the large chromatin loop. The findings of these studies support a mechanism for intergenic SNPs that can promote cancer through the regulation of distal genes by utilizing preexisting large chromatin loops. PMID:20065031

  8. Correlation of chromosomal polysomy with overexpression of c-myc and c-erbB-2 in primary nasopharyngeal carcinoma: Tissue microarray study

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Many genes may be involved in nasopharyngeal carcinoma (NPC) development and progression. Several known oncogenes, including c-myc and c-erb-B2, have been shown to have structural alteration and aberrant expression in NPC. Here, we constructed a tissue microarray to determine the status of c-myc and c-erbB-2 oncogenes at the DNA and protein levels using interphase fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) and to define the diagnostic, prognostic importance of the genetic changes. Results showed that amplification of c-myc and c-erbB-2 was not found in NPC. Polysomy 8 and 17 were observed in 43%-50% and 20%-27% of NPC tumors, respectively. Overexpressions of c-myc and c-erbB-2 oncoproteins were detected in 53.6% and 54.5% cases of NPC with polysomy 8 and 17, respectively. There was no significant correlation between c-myc and c-erbB-2 staining and the clinical stage. But overexpression of c-erbB-2 was associated with polysomy 17 in NPC. These findings suggest that chromosomal polysomy, not gene amplification, may be partially responsible for the upregulated expression of c-erbB-2 oncogene in NPC.

  9. Simultaneous translocations of FGFR3/MMSET and CCND1 into two different IGH alleles in multiple myeloma: lack of concurrent activation of both proto-oncogenes.

    Science.gov (United States)

    Sáez, Borja; Martín-Subero, José I; Lahortiga, Idoya; Largo, Cristina; Larrayoz, María J; Odero, María D; Prosper, Felipe; Cigudosa, Juan C; Siebert, Reiner; Calasanz, María J

    2007-05-01

    The simultaneous occurrence of two different translocations affecting both alleles of the IGH gene has rarely been reported in multiple myeloma. In such a case, two different oncogenes might become transcriptionally deregulated. To investigate this hypothesis, we have characterized the plasma cell leukemia cell line SK-MM2 and a primary myeloma both carrying simultaneous IGH-FGFR3/MMSET and IGH-CCND1 fusions as shown by multicolor fluorescence in situ hybridization. Remarkably, quantitative real-time polymerase chain reaction demonstrated that only one of the oncogene loci was transcriptionally upregulated in both instances. Moreover, the upregulated oncogenes differed between both samples. Thus, biallelic IGH translocations might exert different pathogenetic effects in plasma cell disorders.

  10. c-myc、p53和p16的表达及GNAS1基因突变在骨的纤维结构不良中的意义%Abnormal expression of c-myc,p53,p16 protein and GNAS1 gene mutation in fibrous dysplasia

    Institute of Scientific and Technical Information of China (English)

    唐娟; 赵红叶; 郑莉; 张惠箴; 蒋智铭

    2009-01-01

    Objective To study the significance of c-myc,p53 and p16 protein expression in fibrous dysplasia,to detect the GNAS1 gene mutation in fibrous dysplasia,and to explore the property of fibrous dysplasia.Methods The expression of c-myc,p53 and p16 protein was evaluated by immunohistochemistry SP method in 35 cases of fibrous dysplasia including 1 FD with malignancy,1 Mazabraud syndrome and 20 control cases (10 cases of bony callus,10 cases of osteosarcoma). Genomic DNA extraction,PCR amplification and gene sequencing were used to detect GNAS1 gene mutation in 35 cases of fibrous dysplasia.Results C-myc protein immunoreactivity was detected in 91 percentage of FD(P=0.001).Compared with the negative control group,the difference was significant.P16 positive waa detected in 34 FD cases(P=0.001).The difference was significant as compared with the positive control group.Positive p53 protein expression was detected in the only 1 case of fibrous dysplasia with malignant transformation.PCR amplification was successful in 12 of 35 FD cases.Two of the 12 FD cases were detected to have GNAS1 gene mutation,in which 1 case waa FD of Mazabraud syndrome,1 case was a monostotic lesion.Concimiom C-myc could be another protooncogene in addition to c-fos in the fibrous dysplasia disease.P53 protein overexpression could be useful in the diagnosis of FD malignancy and in the prediction of the prognosis of FD.The abnormal expression of the gene p16 might play an important role in the formation of FD.The GNAS1 mutation exist in FD.All of the results indicate that FD could be a neoplasia disease.caused by multiple factors leading to a dysfunction of bone development.%目的 检测c-myc、p53和p16蛋白在骨的纤维结构不良(FD)中的表达及其意义,检测FD中GNAS1基因第8外显子突变,探讨FD的病变性质.方法 采用免疫组织化学SP法检测35例FD(包括1例FD恶变,1例Mazabraud综合征)及20例对照组(10例骨痂、10例骨肉瘤)中c-myc、p53和p16蛋白表达.

  11. 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.

  12. Brief inactivation of c-Myc is not sufficient for sustained regression of c-Myc-induced tumours of pancreatic islets and skin epidermis

    Directory of Open Access Journals (Sweden)

    Zervou Sevasti

    2004-12-01

    Full Text Available Abstract Background Tumour regression observed in many conditional mouse models following oncogene inactivation provides the impetus to develop, and a platform to preclinically evaluate, novel therapeutics to inactivate specific oncogenes. Inactivating single oncogenes, such as c-Myc, can reverse even advanced tumours. Intriguingly, transient c-Myc inactivation proved sufficient for sustained osteosarcoma regression; the resulting osteocyte differentiation potentially explaining loss of c-Myc's oncogenic properties. But would this apply to other tumours? Results We show that brief inactivation of c-Myc does not sustain tumour regression in two distinct tissue types; tumour cells in pancreatic islets and skin epidermis continue to avoid apoptosis after c-Myc reactivation, by virtue of Bcl-xL over-expression or a favourable microenvironment, respectively. Moreover, tumours progress despite reacquiring a differentiated phenotype and partial loss of vasculature during c-Myc inactivation. Interestingly, reactivating c-Myc in β-cell tumours appears to result not only in further growth of the tumour, but also re-expansion of the accompanying angiogenesis and more pronounced β-cell invasion (adenocarcinoma. Conclusions Given that transient c-Myc inactivation could under some circumstances produce sustained tumour regression, the possible application of this potentially less toxic strategy in treating other tumours has been suggested. We show that brief inactivation of c-Myc fails to sustain tumour regression in two distinct models of tumourigenesis: pancreatic islets and skin epidermis. These findings challenge the potential for cancer therapies aimed at transient oncogene inactivation, at least under those circumstances where tumour cell differentiation and alteration of epigenetic context fail to reinstate apoptosis. Together, these results suggest that treatment schedules will need to be informed by knowledge of the molecular basis and

  13. Acinar-to-ductal metaplasia accompanies c-myc-induced exocrine pancreatic cancer progression in transgenic rodents.

    Science.gov (United States)

    Grippo, Paul J; Sandgren, Eric P

    2012-09-01

    Several important characteristics of exocrine pancreatic tumor pathogenesis remain incompletely defined, including identification of the cell of origin. Most human pancreatic neoplasms are ductal adenocarcinomas. However, acinar cells have been proposed as the source of some ductal neoplasms through a process of acinar-to-ductal metaplasia. The oncogenic transcription factor c-myc is associated with human pancreatic neoplasms. Transgenic mice overexpressing c-myc under control of acinar cell-specific elastase (Ela) gene regulatory elements not only develop acinar cell carcinomas but also mixed neoplasms that display both acinar-like neoplastic cells and duct-like neoplastic cells. In this report, we demonstrate that, first, c-myc is sufficient to induce acinar hyperplasia, though neoplastic lesions develop focally. Second, cell proliferation remains elevated in the neoplastic duct cell compartment of mixed neoplasms. Third, the proliferation/apoptosis ratio in cells from all lesion types remains constant, suggesting that differential regulation of these processes is not a feature of cancer progression in this model. Fourth, before the development of mixed neoplasms, there is transcriptional activation of the duct cell-specific cytokeratin-19 gene promoter in multicellular foci of amylase-positive acinar neoplasms. This observation provides direct evidence for metaplasia as the mechanism underlying development of ductal neoplastic cells within the context of an acinar neoplasm and suggests that the stimulus for this transformation acts over a multicellular domain or field within a neoplasm. Finally, focal ductal elements develop in some acinar cell carcinomas in Ela-c-myc transgenic rats, indicating that myc-associated acinar-to-ductal metaplasia is not restricted to the mouse.

  14. The inhibition effects of the c-myc targeting CRISPR/Cas9 adenovirus system on hepatoma cells%靶向 c-myc 基因的 CRISPR/Cas9腺病毒系统对肝癌的抑制作用

    Institute of Scientific and Technical Information of China (English)

    连竹生; 梁鑫; 金桂花; 吴领知; 韩苏夏

    2016-01-01

    目的:设计、构建并包装靶向 c-myc 基因的 CRISPR/Cas9腺病毒;评估靶向 c-myc 基因的 CRISPR/Cas9腺病毒系统对肝癌的抑制作用。方法:采用生物信息学网站设计靶向 c-myc 基因的 gRNA,以 GFP 作为对照设计GFP gRNA;通过 T7E1筛选出编辑效率高的 gRNA 并将筛选的 gRNA 构建 CRISPR/Cas9腺病毒载体并包装腺病毒,通过分析细胞增殖、周期和凋亡及迁移能力的变化来评估靶向 c-myc 基因的 CRISPR/Cas9腺病毒系统对肝癌的抑制作用。结果:成功设计、构建并包装靶向 c-myc 基因的 CRISPR/Cas9腺病毒;靶向 c-myc 基因的 CRISPR/Cas9腺病毒系统能够显著抑制 Hepa1-6细胞的增殖和迁移、阻滞细胞周期进程,但对细胞凋亡无影响。结论:靶向 c-myc 基因的 CRISPR/Cas9腺病毒系统可在细胞水平明显抑制肝癌细胞的生长。%Aim:To design,construct and package the CRISPR/Cas9 adenovirus system for targeting the mouse c-myc gene;To evaluate the inhibition efficiency of the constructed adenovirus system on c-myc gene in hepatoma cells.Methods:We designed gRNAs for targeting the mouse c-myc gcontrolene and used another gene (gRNAs for GFP)as control based on bioinformatics website.The editing efficiencies of these gRNAs were determined by T7E1 cleavage.The gRNAs with higher editing efficiency were se-lected and packed into adenovirus for the following experiments.Firstly,Hepa 1-6 cells were infected with the constructed adenovirus,then cell proliferation,cell cycle,cell apoptosis and migration assays were detected to de the inhibition efficiency of the adenovirus on hepatoma cells.Statistical analyses were performed with SPSS(version 18.0)and t-test,P <0.05 was considered statistically significant.Re-sults:The CRISPR/Cas9 adenovirus system targeting the mouse c-myc gene was successfully designed constructed and packaged.Compared with the control group,the experiment groups (with CRISPR/Cas9

  15. Primary structure and functional scFv antibody expression of an antibody against the human protooncogen c-myc.

    Science.gov (United States)

    Fuchs, P; Breitling, F; Little, M; Dübel, S

    1997-06-01

    The immunoglobulin heavy- and light-chain variable region (Vh and Vl) genes were isolated from Myc1-9E10 hybridoma cells, which secreted monoclonal antibody against human oncogen c-myc. The expression vector pOPE52-c-myc was constructed for the recombinant production in E. coli. A 30 kDa single chain fragment (scFv) expression product was found in the periplasmic space by SDS-PAGE and immunoblotting. A significant fraction was processed correctly as demonstrated with an antiserum recognizing the processed aminoterminus only. The specific binding of the scFv fragment to the peptide epitope of the maternal monoclonal antibody was demonstrated and the primary sequence of the variable regions was determined. Sequence comparison with previously published partial Vh and Vl sequences from this hybridoma cell line revealed a genetic heterogeneity for the light chain variable region. The potential use of this scFv as a new tool for detection and purification of tagged proteins, for adding costimulatory signals to the surface of cancer cells as well as for analyzing c-myc function in the living cell by cytoplasmic expression is discussed.

  16. 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.

  17. Glutathione Depletion Induced by c-Myc Downregulation Triggers Apoptosis on Treatment with Alkylating Agents

    Directory of Open Access Journals (Sweden)

    Annamaria Biroccio

    2004-05-01

    Full Text Available 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, 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 druginduced 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 Baxicytochrome c redistribution. The relationship among c-Myc, GSH content, 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.

  18. MicroRNA-490-3p inhibits proliferation of A549 lung cancer cells by targeting CCND1

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Haihua; Yang, Tao; Fu, Shaozi; Chen, Xiaofan; Guo, Lei; Ni, Yiming, E-mail: ni_yiming@hotmail.com

    2014-01-31

    Highlights: • We examined the level of miR-490-3p in A549 lung cancer cells compared with normal bronchial epithelial cell line. • We are the first to show the function of miR-490-3p in A549 lung cancer cells. • We demonstrate CCND1 may be one of the targets of miR-490-3p. - Abstract: MicroRNAs (miRNAs) are small non-coding RNAs that negatively regulate the translation of messenger RNAs by binding their 3′-untranslated region (3′UTR). In this study, we found that miR-490-3p is significantly down-regulated in A549 lung cancer cells compared with the normal bronchial epithelial cell line. To better characterize the role of miR-490-3p in A549 cells, we performed a gain-of-function analysis by transfecting the A549 cells with chemically synthesized miR-490-3P mimics. Overexpression of miR-490-3P evidently inhibits cell proliferation via G1-phase arrest. We also found that forced expression of miR-490-3P decreased both mRNA and protein levels of CCND1, which plays a key role in G1/S phase transition. In addition, the dual-luciferase reporter assays indicated that miR-490-3P directly targets CCND1 through binding its 3′UTR. These findings indicated miR-490-3P could be a potential suppressor of cellular proliferation.

  19. Molecular characterizations of Nop16 in murine mammary tumors with varying levels of c-Myc.

    Science.gov (United States)

    Kundel, Donald W; Stromquist, Emily; Greene, Amy L; Zhdankin, Olga; Regal, Ronald R; Rose-Hellekant, Teresa A

    2012-04-01

    NOP16, also known as HSPC111, has been identified as a MYC and estrogen regulated gene in in vitro studies, hence coexpression levels were strongly correlated. Importantly, high expression of NOP16 was associated with poor clinical outcome in breast cancer patients. However, coexpression of NOP16, MYC and estrogen receptor (ESR1) varied widely in tumors and cell lines suggesting that transcriptional regulation differed according to pathological environments. The goal of this study was to determine the expression patterns of Nop16, Myc and Esr1 in murine mammary tumors with disparate histopathological and molecular features. We hypothesized that tumor environments with relatively high Myc levels would have different coexpression patterns than tumor environments with relatively low Myc levels. We measured levels of Myc and Nop16 mRNA and protein in tumors from WAP-c-myc mice that were of high grade and metastasized frequently. In contrast, Myc and Nop16 mRNA and proteins levels were significantly lower in the less aggressive tumors that developed in NRL-TGFα mice. Tumors from both mouse lines express ESR1 protein and we found that Esr1 mRNA levels correlated positively with Myc levels in both models. However, Myc and Nop16 transcript levels correlated positively only in tumors from NRL-TGFα mice. We identified prominent NOP16 protein in nuclei and less prominent staining in the cytoplasm of luminal cells of ducts and lobules from normal mammary glands as well as in hyperplasias and tumors obtained from NRL-TGFα mice. This staining pattern was reversed in tumors from WAP-c-Myc mice as nuclear staining was faint or absent and cytoplasmic staining more pronounced. In summary, the regulation of expression and localization of NOP16 varies in tumor environments with high versus low MYC levels and demonstrate the importance of stratifying clinical breast cancers based on MYC levels.

  20. Gene amplification in carcinogenesis

    Directory of Open Access Journals (Sweden)

    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.

  1. c-myc down-regulation induces apoptosis in human cancer cell lines exposed to RPR-115135 (C31H29NO4), a non-peptidomimetic farnesyltransferase inhibitor.

    Science.gov (United States)

    Russo, Patrizia; Arzani, Dario; Trombino, Sonya; Falugi, Carla

    2003-01-01

    A therapeutic strategy that relies on the use of c-myc antisense in combination with a farnesyltransferase inhibitor, RPR-115135 (C31H29NO4), was studied in human cancer cell lines carrying different mutations (Ras, p53, myc amplification). Cell proliferation was strongly inhibited by the combination and was observed when c-myc oligo (at a concentration that down-regulates c-myc expression) was followed by RPR-115135. Cell cycle analysis demonstrated an accumulation in G0-G1 phase and a tendency to apoptosis (not detectable in cells treated with a single agent). Morphological examination and DNA fragmentation assays (filter binding and enzyme-linked immunosorbent assay DNA fragmentation) confirmed the induction of apoptosis. Apoptosis was not p53- and/or p21(waf-1)-dependent, and the key effector was caspase activation. The combination induced Bax expression and Bcl-2 inhibition. Down-regulation of c-myc amplification carried out a specific role exclusively when Ras was mutated. Exposure of human proliferating lymphocytes to combination did not result in cytotoxicity, suggesting that mechanisms regulating c-myc gene expression during normal T cell proliferation might not be involved. Because of the high percentage of human tumors overexpressing c-myc mRNA and/or protein and, simultaneously, harboring oncogenic Ras mutants (i.e., colon cancers), interrupting the myc- and Ras-signaling pathway would be one of the major focuses on therapy of these types of tumors.

  2. TELOMERASE ACTIVITY IN COLORECTAL CARCINOMA AND ITS CORRELATION WITH EXPRESSION OF C-MYC

    Institute of Scientific and Technical Information of China (English)

    LIU Jian-Lun; GE Lian-ying; ZHANG Gui-nian

    2005-01-01

    Objective: To study the role of telomerase activity and c-myc in pathogenesis and progression of colorectal carcinoma,and to investigate the possible regulatory mechanism of telomerase activation. Methods: A modified telomeric repeat amplification protocol (TRAP) and immunohistochemical staining was used to detect telomerase activity and the expression of c-myc in tissue samples from colorectal carcinoma, paracarcinomatousl tissues, normal mucosa, and adenomatoid polyp.Results: The positive rates of telomerase activity and c-myc expression were 83.33% and 80.00% in colorectal carcinoma,13.33% and 23.33% in paracarcinomatousl tissues, 13.33% and 20.00% in normal mucosa, and 10.00% and 45.00% in adenomatoid polyp respectively, they were significantly higher in colorectal carcinoma than in paracarcinomatousl tissues,normal mucosa, and adenomatoid polyp (P<0.05). The rates of telomerase activity and c-myc expression were much higher in colorectal carcinoma with lymph nodes metastases than that without lymph nodes metastases. The expression of c-myc was found being significantly higher in the telomerase positive colorectal carcinoma than in the telomerase negative group(P<0.05). Conclusion: The activation of telomerase and abnormal expression of c-myc might play an important role in the process of carcinogenesis and progression of colorectal carcinoma. The over-expression of c-myc may be related to telomerase activation and up-regulation in colorectal carcinoma.

  3. Sulforaphane Inhibits c-Myc-Mediated Prostate Cancer Stem-Like Traits.

    Science.gov (United States)

    Vyas, Avani R; Moura, Michelle B; Hahm, Eun-Ryeong; Singh, Krishna Beer; Singh, Shivendra V

    2016-11-01

    Preventive and therapeutic efficiencies of dietary sulforaphane (SFN) against human prostate cancer have been demonstrated in vivo, but the underlying mechanism(s) by which this occurs is poorly understood. Here, we show that the prostate cancer stem cell (pCSC)-like traits, such as accelerated activity of aldehyde dehydrogenase 1 (ALDH1), enrichment of CD49f+ fraction, and sphere forming efficiency, are attenuated by SFN treatment. Interestingly, the expression of c-Myc, an oncogenic transcription factor that is frequently deregulated in prostate cancer cells, was markedly suppressed by SFN both in vitro and in vivo. This is biologically relevant, because the lessening of pCSC-like phenotypes mediated by SFN was attenuated when c-Myc was overexpressed. Naturally occurring thio, sulfinyl, and sulfonyl analogs of SFN were also effective in causing suppression of c-Myc protein level. However, basal glycolysis, a basic metabolic pathway that can also be promoted by c-Myc overexpression, was not largely suppressed by SFN, implying that, in addition to c-Myc, there might be another SFN-sensitive cellular factor, which is not directly involved in basal glycolysis, but cooperates with c-Myc to sustain pCSC-like phenotypes. Our study suggests that oncogenic c-Myc is a target of SFN to prevent and eliminate the onset of human prostate cancer. J. Cell. Biochem. 117: 2482-2495, 2016. © 2016 Wiley Periodicals, Inc.

  4. c-Myc Alteration Determines the Therapeutic Response to FGFR Inhibitors.

    Science.gov (United States)

    Liu, Hongyan; Ai, Jing; Shen, Aijun; Chen, Yi; Wang, Xinyi; Peng, Xia; Chen, Hui; Shen, Yanyan; Huang, Min; Ding, Jian; Geng, Meiyu

    2017-02-15

    Purpose: Lately, emerging evidence has suggested that oncogenic kinases are associated with specific downstream effectors to govern tumor growth, suggesting potential translational values in kinase-targeted cancer therapy. Tyrosine kinase FGFR, which is aberrant in various cancer types, is one of the most investigated kinases in molecularly targeted cancer therapy. Herein, we investigated whether there exists key downstream effector(s) that converges FGFR signaling and determines the therapeutic response of FGFR-targeted therapy.Experimental Design: A range of assays was used to assess the role of c-Myc in FGFR aberrant cancers and its translational relevance in FGFR-targeted therapy, including assessment of drug sensitivity using cell viability assay, signaling transduction profiling using immunoblotting, and in vivo antitumor efficacy using cancer cell line-based xenografts and patient-derived xenografts models.Results: We discovered that c-Myc functioned as the key downstream effector that preceded FGFR-MEK/ERK signaling in FGFR aberrant cancer. Disruption of c-Myc overrode the cell proliferation driven by constitutively active FGFR. FGFR inhibition in FGFR-addicted cancer facilitated c-Myc degradation via phosphorylating c-Myc at threonine 58. Ectopic expression of undegradable c-Myc mutant conferred resistance to FGFR inhibition both in vitro and in vivo c-Myc level alteration stringently determined the response to FGFR inhibitors, as demonstrated in FGFR-responsive cancer subset, as well as cancers bearing acquired or de novo resistance to FGFR inhibition.Conclusions: This study reveals a stringent association between FGFR and the downstream effector c-Myc in FGFR-dependent cancers, and suggests the potential therapeutic value of c-Myc in FGFR-targeted cancer therapy. Clin Cancer Res; 23(4); 974-84. ©2016 AACR.

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

    Directory of Open Access Journals (Sweden)

    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.

  6. The use of FISH-comet to detect c-Myc and TP 53 damage in extended-term lymphocyte cultures treated with terbuthylazine and carbofuran.

    Science.gov (United States)

    Mladinic, Marin; Zeljezic, Davor; Shaposhnikov, Sergey A; Collins, Andrew R

    2012-05-20

    Terbuthylazine and carbofuran are suspected to cause non-Hodgkin's lymphoma and lung cancer. We evaluated the effects of prolonged exposure to low concentrations on primary DNA damage by comet assay, and on the structural integrity of c-Myc and TP 53 genes by FISH-comet. Another novelty in studying these pesticides' genotoxicity is the use of 14-day extended-term human lymphocyte cultures. Concentrations corresponded to values of ADI and OEL: for terbuthylazine 0.58 ng/ml and 8 ng/ml; for carbofuran 8 ng/ml and 21.6 ng/ml, respectively. A possible effect of metabolic activation (S9) was also considered. Carbofuran treatment induced a significant migration of DNA into the tail in a concentration-dependent manner, while for terbuthylazine the effect was significant only at the higher concentration. Terbuthylazine caused migration of both c-Myc signals into the comet tail. A significant occurrence of TP 53 signals in the tail was observed at 8 ng/ml. Prolonged carbofuran treatment significantly elevated the migration of a single c-Myc signal into the tail in a concentration-dependent manner. With S9, distribution of signals shifted toward increased presence of both signals in tail. Our results showed impaired structural integrity of c-Myc and TP 53 due to prolonged exposure to terbuthylazine and carbofuran.

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

    Science.gov (United States)

    Ruiz-Ramos, Ruben; López-Carrillo, Lizbeth; Albores, Arnulfo; Hernández-Ramírez, Raúl U; Cebrian, Mariano E

    2009-12-15

    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 microM) 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 ( or =5 microM) 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.

  8. Regulation of human ornithine decarboxylase expression following prolonged quiescence: role for the c-Myc/Max protein complex.

    Science.gov (United States)

    Peña, A; Wu, S; Hickok, N J; Soprano, D R; Soprano, K J

    1995-02-01

    WI-38 cells can remain quiescent for long periods of time and still be induced to reenter the cell cycle by the addition of fresh serum. However, the longer these cells remain growth arrested, the more time they require to enter S phase. This prolongation of the prereplicative phase has been localized to a point early in G1, after the induction of "immediate early" G1 genes such as c-fos and c-jun but before maximal expression of "early" G1 genes such as ornithine decarboxylase (ODC). Understanding the molecular basis for ODC mRNA induction can therefore provide information about the molecular events which regulate the progression of cells out of long-term quiescence into G1 and subsequently into DNA synthesis. Studies utilizing electrophoretic mobility shift assays (EMSA) of nuclear extracts from short- and long-term quiescent WI-38 cells identified a region of the human ODC promoter at -491 bp to -474 bp which exhibited a protein binding pattern that correlated with the temporal pattern of ODC mRNA expression. The presence of a CACGTG element within this fragment, studies with antibodies against c-Myc and Max, the use of purified recombinant c-Myc protein in the mobility shift assay, and antisense studies suggest that these proteins can specifically bind this portion of the human ODC promoter in a manner consistent with growth-associated modulation of the expression of ODC and other early G1 genes following prolonged quiescence. These studies suggest a role for the c-Myc/Max protein complex in regulating events involved in the progression of cells out of long-term quiescence into G1 and subsequently into S.

  9. c-myc protein can be substituted for SV40 T antigen in SV40 DNA replication.

    OpenAIRE

    Iguchi-Ariga, Sanae M. M.; Itani, Teru; Yamaguchi, Masamitsu; Ariga, Hiroyoshi

    1987-01-01

    Replicating activity of SV40 origin-containing plasmid was tested in human cells as well as in monkey CosI cells. All the plasmids possessing SV40 ori sequences could replicate, even in the absence of SV40 T antigen, in human HL-60 and Raji cells which are expressing c-myc gene at high level. The copy numbers of the replicated plasmids in these human cells were 1/100 as high as in monkey CosI cells which express SV40 T antigen constitutively. Exactly the same plasmids as the transfected origi...

  10. Critical B-lymphoid cell intrinsic role of endogenous MCL-1 in c-MYC-induced lymphomagenesis

    OpenAIRE

    Grabow, S; Kelly, G L; Delbridge, A R D; Kelly, P N; Bouillet, P; Adams, J M; Strasser, A.

    2016-01-01

    Evasion of apoptosis is critical for tumorigenesis, and sustained survival of nascent neoplastic cells may depend upon the endogenous levels of pro-survival BCL-2 family members. Indeed, previous studies using gene-targeted mice revealed that BCL-XL, but surprisingly not BCL-2, is critical for the development of c-MYC-induced pre-B/B lymphomas. However, it remains unclear whether another pro-survival BCL-2 relative contributes to their development. MCL-1 is an intriguing candidate, because it...

  11. Theabrownin Inhibits Cell Cycle Progression and Tumor Growth of Lung Carcinoma through c-myc-Related Mechanism

    Science.gov (United States)

    Zhou, Li; Wu, Feifei; Jin, Wangdong; Yan, Bo; Chen, Xin; He, Yingfei; Yang, Weiji; Du, Wenlin; Zhang, Qiang; Guo, Yonghua; Yuan, Qiang; Dong, Xiaoqiao; Yu, Wenhua; Zhang, Jin; Xiao, Luwei; Tong, Peijian; Shan, Letian; Efferth, Thomas

    2017-01-01

    Green tea, the fresh leaves of Camellia sinensis, is not only a health-promoting beverage but also a traditional Chinese medicine used for prevention or treatment of cancer, such as lung cancer. Theabrownin (TB) is the main fraction responsible for the medicinal effects of green tea, but whether it possesses anti-cancer effect is unknown yet. This study aimed to determine the in vitro and in vivo anti-lung cancer effect of TB and explore the underlying molecular mechanism, by using A549 cell line and Lewis lung carcinoma-bearing mice. In cellular experiment, MTT assay was performed to evaluate the inhibitory effect and IC50 values of TB, and flow cytometry was conducted to analyze the cell cycle progression affected by TB. In animal experiment, mice body mass, tumor incidence, tumor size and tumor weight were measured, and histopathological analysis on tumor was performed with Transferase dUTP nick-end labeling staining. Real time PCR and western blot assays were adopted to detect the expression of C-MYC associated genes and proteins for mechanism clarification. TB was found to inhibit A549 cell viability in a dose- and time-dependent manner and block A549 cell cycle at G0/G1 phase. Down-regulation of c-myc, cyclin A, cyclin D, cdk2, cdk4, proliferation of cell nuclear antigen and up-regulation of p21, p27, and phosphate and tension homolog in both gene and protein levels were observed with TB treatment. A c-myc-related mechanism was thereby proposed, since c-myc could transcriptionally regulate all other genes in its downstream region for G1/S transitions of cell cycle and proliferation of cancer cells. This is the first report regarding the anti-NSCLC effect and the underlying mechanism of TB on cell cycle progression and proliferation of A549 cells. The in vivo data verified the in vitro result that TB could significantly inhibit the lung cancer growth in mice and induce apoptosis on tumors in a dose-dependent manner. It provides a promising candidate of natural

  12. ROCK has a crucial role in regulating prostate tumor growth through interaction with c-Myc.

    Science.gov (United States)

    Zhang, C; Zhang, S; Zhang, Z; He, J; Xu, Y; Liu, S

    2014-12-04

    Rho-associated kinase (ROCK) has an essential role in governing cell morphology and motility, and increased ROCK activity contributes to cancer cell invasion and metastasis. Burgeoning data suggest that ROCK is also involved in the growth regulation of tumor cells. However, thus far, the molecular mechanisms responsible for ROCK-governed tumor cell growth have not been clearly elucidated. Here we showed that inhibition of ROCK kinase activity, either by a selective ROCK inhibitor Y27632 or by specific ROCK small interfering RNA (siRNA) molecules, attenuated not only motility but also the proliferation of PC3 prostate cancer cells in vitro and in vivo. Importantly, mechanistic investigation revealed that ROCK endowed cancer cells with tumorigenic capability, mainly by targeting c-Myc. ROCK could increase the transcriptional activity of c-Myc by promoting c-Myc protein stability, and ROCK inhibition reduced c-Myc-mediated expression of mRNA targets (such as HSPC111) and microRNA targets (such as miR-17-92 cluster). We provided evidence demonstrating that ROCK1 directly interacted with and phosphorylated c-Myc, resulting in stabilization of the protein and activation of its transcriptional activity. Suppression of ROCK-c-Myc downstream molecules, such as c-Myc-regulated miR-17, also impaired tumor cell growth in vitro and in vivo. In addition, c-Myc was shown to exert a positive feedback regulation on ROCK by increasing RhoA mRNA expression. Therefore, inhibition of ROCK and its stimulated signaling might prove to be a promising strategy for restraining tumor progression in prostate cancer.

  13. Alternative translation of the proto-oncogene c-myc by an internal ribosome entry site.

    Science.gov (United States)

    Nanbru, C; Lafon, I; Audigier, S; Gensac, M C; Vagner, S; Huez, G; Prats, A C

    1997-12-19

    The human proto-oncogene c-myc encodes two proteins, c-Myc1 and c-Myc2, from two initiation codons, CUG and AUG, respectively. It is also transcribed from four alternative promoters (P0, P1, P2, and P3), giving rise to different RNA 5'-leader sequences, the long sizes of which suggest that they must be inefficiently translated by the classical ribosome scanning mechanism. Here we have examined the influence of three c-myc mRNA 5'-leaders on the translation of chimeric myc-CAT mRNAs. We observed that in the reticulocyte rabbit lysate, these 5'-leaders lead to cap-independent translation initiation. To determine whether this kind of initiation resulted from the presence of an internal ribosome entry site (IRES), COS-7 cells were transfected with bicistronic vectors containing the different c-myc 5'-leaders in the intercistronic region. An IRES was identified, requiring elements located within the P2 leader, between nucleotides -363 and -94 upstream from the CUG start codon. This is the first demonstration of the existence of IRES-dependent translation for a proto-oncogene. This IRES could be a translation enhancer, allowing activation of c-myc expression under the control of trans-acting factors and in response to specific cell stimuli.

  14. A therapeutic role for targeting c-Myc/Hif-1-dependent signaling pathways.

    Science.gov (United States)

    Podar, Klaus; Anderson, Kenneth C

    2010-05-01

    Deregulated c-Myc occurs in approximately 30% of human cancers. Similarly, hypoxia-inducible factor (HIF) is commonly overexpressed in a variety of human malignancies. Under physiologic conditions, HIF inhibits c-Myc activity; however, when deregulated oncogenic c-Myc collaborates with HIF in inducing the expression of VEGF, PDK1 and hexokinase 2. Most of the knowledge of HIF derives from studies investigating a role of HIF under hypoxic conditions, however, HIF-1alpha stabilization is also found in normoxic conditions. Specifically, under hypoxic conditions HIF-1-mediated regulation of oncogenic c-Myc plays a pivotal role in conferring metabolic advantages to tumor cells as well as adaptation to the tumorigenic micromilieu. In addition, our own results show that under normoxic conditions oncogenic c-Myc is required for constitutive high HIF-1 protein levels and activity in Multiple Myeloma (MM) cells, thereby influencing VEGF secretion and angiogenic activity within the bone marrow microenvironment. Further studies are needed to delineate the functional relevance of HIF, MYC, and the HIF-MYC collaboration in MM and other malignancies, also integrating the tumor microenvironment and the cellular context. Importantly, early studies already demonstrate promising preclinical of novel agents, predominantly small molecules, which target c-Myc, HIF or both.

  15. Transcript Regulation of Human Telomerase Reverse Transcriptase by c-myc and mad1

    Institute of Scientific and Technical Information of China (English)

    Lin ZOU; Peng-Hui ZHANG; Chun-Li LUO; Zhi-Guang TU

    2005-01-01

    Telomerase activity is highly positive correlated to most malignant neoplasms. Human telomerase reverse transcriptase (hTERT) is the rate-limiting factor of telomerase activity. Recent studies have shown that the expression of hTERT is mainly determined by its transcript regulation. Among the transcript regulation factors of hTERT, c-myc and mad1 are well known. Here, we constructed c-myc and mad1 eukaryotic expression vectors, then co-transfected them with the wild-type (Tw) or mutant hTERT promoter (Td)luciferase reporter plasmid, which were double-mutated in the E-box sequences from CACGTG to CACCTG of Tw. The change of luciferase activity in different cells was detected. The results showed that Tw was obviously activated in T24 and EJ bladder cancer cells, but not in normal fibrocytes. c-myc and mad1 had positive and negative effects respectively on the Tw transcript in a dose-dependent manner, while the roles of c-myc and mad1 in regulating the Td transcript were reversed. c-myc combined with mad1 can downregulate Tw but not Td. These observations indicate that c-myc and mad1 can regulate the hTERT transcript in a different manner in hTERT positive cells, but not in normal cells. This may provide an insight into some telomerase-related carcinogenesis mechanisms.

  16. Differential regulation of the c-Myc/Lin28 axis discriminates subclasses of rearranged MLL leukemia

    Science.gov (United States)

    Chen, Lili; Sun, Yuqing; Wang, Jingya; Jiang, Hui; Muntean, Andrew G.

    2016-01-01

    MLL rearrangements occur in myeloid and lymphoid leukemias and are generally associated with a poor prognosis, however this varies depending on the fusion partner. We modeled acute myeloid leukemia (AML) in mice using various MLL fusion proteins (MLL-FPs) and observed significantly different survival outcomes. To better understand the differences between these leukemias, we examined the genome wide expression profiles of leukemic cells transformed with different MLL-FPs. RNA-sequencing and pathway analysis identified the c-Myc transcriptional program as one of the top distinguishing features. c-Myc protein levels were highly correlative with AML disease latency in mice. Functionally, overexpression of c-Myc resulted in a more aggressive proliferation rate in MLL-FP cell lines. While all MLL-FP transformed cells displayed sensitivity to BET inhibitors, high c-Myc expressing cells showed greater resistance to Brd4 inhibition. The Myc target Lin28B was also differentially expressed in MLL-FP cell lines in agreement with c-Myc expression. Examination of Lin28B miRNAs targets revealed that let-7g was significantly increased in leukemic cells associated with the longest disease latency and forced let-7g expression induced differentiation of leukemic blasts. Thus, differential regulation of the c-Myc/Lin28/let-7g program by different MLL-FPs is functionally related to disease latency and BET inhibitor resistance in MLL leukemias. PMID:27007052

  17. Incidence of HPV Infection in Oral Squamous Cell Carcinoma and Its Association with the Presence of p53 & c-myc Mutation : A Case Control Study in Muwardi Hospital Surakarta

    Directory of Open Access Journals (Sweden)

    Adi Prayitno

    2012-12-01

    Full Text Available Introduction: Annual incidence rates for oral and pharyngeal cancer are estimated at 25 cases per 100,000 in developing countries. Human papilloma virus (HPV was implicated in pathogenesis of Cancer. The mutations of p53 and c-myc are found 50% in cancer. Objective: Aims of this research were to know the incidence of OSSC patient which realized HPV infection without p53 and c-myc gene mutation. Materials and Methods: Tissue biopsy frozen sections were taken from BOSC (Benign Oral Squamous Cell and OSCC (Oral Squamous Cell Carcinoma patients collected from Oral and Dental Departement of dr Muwardi Distric Hospital in Surakarta from January 2007 to January 2008. To amplify L1-HPV gene for fixed the HPV stressor. To amplify p53 and c-myc genes, continued with SSCP (Single Strand Conformational Polymorphisme analysis and followed with measurement using densitometer, to see mutation existence. The collected data were analyzed with Chi Square. Results: BOSC patient identified 23% with HPV infections and OSCC patient identified 73% with HPV infections. Hundred percent BOSC patient with HPV infection without mutation in p53 gene and c-myc gene, 81% OSCC patient with HPV infection without mutation in p53 gene and 91% OSCC patient with HPV infection without mutation in c-myc gene. Chi  square analysis showed significant difference between BOSC and OSCC patients with HPV infection without mutation in p53 and c-myc gene. Conclusion: HPV is a factor for pathogenesis of OSCC.DOI: 10.14693/jdi.v17i2.44

  18. THE EFFECTS OF RETINOIC ACID ON EXPRESSION OF C-MYC, C-FOS IN LEUKEMIC PROMYELOCYTES

    Institute of Scientific and Technical Information of China (English)

    邵国英; 徐荣婷; 孙关林; 欧阳仁荣; 应大明

    1992-01-01

    The expression of c-myc, c-fos of leukemic promyelocytes (HL-60 and acute promyelocytic leukemia cells) from 18 acute promyelocytic leukemia (APL) patients treated with all-trans retinoic acid (RA) in vitro was studied. There was no expression of c-fos in HL-60 cells and APL cells from 17 patients. But in one case, a slight expression of c-fos in leukemic cells was observed, and the alteration of expression level was found during the treatment of the cells with RA in vitro. The expression of c-myc in HL-60 cells induced by RA was altered, decrease in the early, increase in the middle, and decline in the later stage were found. The c-myc expression in leukemic cells of eighteen APL patients was variable. There was c-myc expression in eleven APL cells, but no expression in the others. The APL cells with c-myc expression were treated with RA in vitro to observe the kinetic changes of c-myc RNA level. The results showed that the expression of c-myc was gradually decreased except in few cases. Using in situ hybridization technique for detecting the alteration of c-myc expression in leukemic cells of two APL patients. the high level of c-myc before RA treatment and low level of c-myc expression after obtaining complete remission induced by RA were found. The possibility of different proto-oncogenes implicated differentiation was discussed.

  19. Microcystin-LR stabilizes c-myc protein by inhibiting protein phosphatase 2A in HEK293 cells.

    Science.gov (United States)

    Fan, Huihui; Cai, Yan; Xie, Ping; Xiao, Wuhan; Chen, Jun; Ji, Wei; Zhao, Sujuan

    2014-05-07

    Microcystin-LR is the most toxic and the most frequently encountered toxin produced by the cyanobacteria in the contaminated aquatic environment. Previous studies have demonstrated that Microcystin-LR is a potential carcinogen for animals and humans, and the International Agency for Research on Cancer has classified Microcystin-LR as a possible human carcinogen. However, the precise molecular mechanisms of Microcystin-LR-induced carcinogenesis remain a mystery. C-myc is a proto-oncogene, abnormal expression of which contributes to the tumor development. Although several studies have demonstrated that Microcystin-LR could induce c-myc expression at the transcriptional level, the exact connection between Microcystin-LR toxicity and c-myc response remains unclear. In this study, we showed that the c-myc protein increased in HEK293 cells after exposure to Microcystin-LR. Coexpression of protein phosphatase 2A and two stable c-myc protein point mutants (either c-myc(T58A) or c-myc(S62A)) showed that Microcystin-LR increased c-myc protein level mainly through inhibiting protein phosphatase 2A activity which altered the phosphorylation status of serine 62 on c-myc. In addition, we also showed that Microcystin-LR could increase c-myc promoter activity as revealed by luciferase reporter assay. And the TATA box for P1 promoter of c-myc might be involved. Our results suggested that Microcystin-LR can stimulate c-myc transcription and stabilize c-myc protein, which might contribute to hepatic tumorigenesis in animals and humans.

  20. 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......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...

  1. Induction of C-FOS, C-MYC and P53 by US -adrenergic receptor (US -AR) stimulation of rat parotid acinar cells (RPAC)

    Energy Technology Data Exchange (ETDEWEB)

    Kousvelari, E.E.; Louis, J.; Curran, T.; Baum, B.J.

    1987-05-01

    Treatment of rats with the US -agonist isoproterenol (ISO) results in dramatically increased parotid gland protein synthesis, processing and cell proliferation. The authors have shown that in RPAC in vitro, US -AR stimulation has similar effect on protein synthesis and processing. Proto-oncogenes have been implicated in growth regulation, differentiation and in mediating some extracellular stimulated events at the level of gene expression. To understand the regulation of cellular events after US -AR stimulation, the expression of c-fos, c-myc and p53 was investigated. RPAC were incubated with or without 10 VM ISO for 15, 30, 60 min. mRNA was isolated from cells and hybridization analysis was performed on nitrocellulose paper-transferred mRNA using TSP-labeled DNA probes. At early time points, the levels of c-fos gene activation in ISO-treated and control cells were comparable. After 60 min of ISO treatment, a sharp 20-30 fold induction of c-fos expression occurred. Similar increases in c-myc and p53 gene expression were observed after 60 min of ISO treatment. The authors data indicate that early effects of US -AR stimulation of RPAC include induction of c-fos, c-myc and p53 gene expression as well as enhanced protein synthesis and processing.

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

    Directory of Open Access Journals (Sweden)

    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.

  3. The long non-coding RNA PARROT is an upstream regulator of c-Myc and affects proliferation and translation

    Science.gov (United States)

    Vučićević, Dubravka; Gehre, Maja; Dhamija, Sonam; Friis-Hansen, Lennart; Meierhofer, David; Sauer, Sascha; Ørom, Ulf Andersson

    2016-01-01

    Long non-coding RNAs are important regulators of gene expression and signaling pathways. The expression of long ncRNAs is dysregulated in cancer and other diseases. The identification and characterization of long ncRNAs is often challenging due to their low expression level and localization to chromatin. Here, we identify a functional long ncRNA, PARROT (Proliferation Associated RNA and Regulator Of Translation) transcribed by RNA polymerase II and expressed at a relatively high level in a number of cell lines. The PARROT long ncRNA is associated with proliferation in both transformed and normal cell lines. We characterize the long ncRNA PARROT as an upstream regulator of c-Myc affecting cellular proliferation and translation using RNA sequencing and mass spectrometry following depletion of the long ncRNA. PARROT is repressed during senescence of human mammary epithelial cells and overexpressed in some cancers, suggesting an important association with proliferation through regulation of c-Myc. With this study, we add to the knowledge of cytoplasmic functional long ncRNAs and extent the long ncRNA-Myc regulatory network in transformed and normal cells. PMID:27129154

  4. Targeting c-Myc on cell growth and vascular endothelial growth factor expression in IN500 glioblastoma cells

    Institute of Scientific and Technical Information of China (English)

    HU Yu-hua; KONG Shi-qi; KONG Hai-bo; WU Jian-liang; CHEN Ze

    2012-01-01

    Background The level of c-Myc is closely associated with high pathological grade and the poor prognosis of gliomas.Vascular endothelial growth factor (VEGF) is the most important angiogenic factor that potently stimulates the proliferation and migration of vascular endothelial cells.This study aimed to address the biological importance of c-Myc in the development of gliomas,we downregulated the expression of c-Myc in the human glioblastoma cell line IN500 and studied the in vitro effect on cellular growth,proliferation,and apoptosis and the expression of VEGF and the in vivo effect on tumor formation in a xenograft mouse model.Methods IN500△ cells were stably transfected with shRNA-expressing plasmids for either c-Myc (pCMYC-shRNA) or as a control (pCtrl-shRNA).Following establishment of stable cells,the mRNA expressions of c-Myc and VEGF were examined by reverse transcription (RT)-PCR,and c-Myc and VEGF proteins by Western blotting and immunohistochemistry.Cell-cycle progression and apoptosis were determined by flow cytometry.The in vivo effect of targeting c-Myc was determined by subcutaneous injection of stable cells into immunodeficient nude mice.Results The stable transfection of pCMYC-shRNA successfully knocked down the steady-state mRNA and protein levels of c-Myc in IN500,which positively correlated with the downregulation of VEGF.Downregulating c-Myc in vitro also led to G1-S arrest and enhanced apoptosis.In vivo,targeting c-Myc reduced xenograft tumor formation and resulted in significantly smaller tumors.Conclusions c-Myc has multiple functions in glioblastoma development that include regulating cell-cycle,apoptosis,and VEGF expression.Targeting c-Myc expression may be a promising therapy for malignant glioma.

  5. 氧化苦参碱对结肠癌LoVo细胞c-myc,PSMD9,CDK4mRNA表达的影响%Effect of Oxymatrine on Expression of c-myc, PSMD9 and CDK4 mRNA in Human Colon Carcinoma LoVo Cells

    Institute of Scientific and Technical Information of China (English)

    彭燕; 韩凌; 孙静; 危建安

    2012-01-01

    目的:探讨氧化苦参碱( oxymatrine,OM)抑制人结肠癌LoVo细胞增殖和诱导凋亡的分子作用机制.方法:采用流式细胞仪检测LoVo细胞凋亡率以及细胞周期分布;采用荧光定量PCR法检测0.25,0.5 g·L-1 OM对LoVo细胞增殖相关基因c -myc,蛋白酶调解因子9(PSMD9),CDK4的基因表达的影响.结果:0.5 g·L-1以下浓度的OM作用结肠癌LoVo细胞48 h,对细胞凋亡无明显影响.0.25 g·L-1 OM作用48 h时可明显抑制人结肠癌LoVo细胞c-myc基因表达(P<0.05).0.5g·L-1 OM作用48 h时可明显抑制LoVo细胞c-myc,CDK4的基因表达(P <0.01,P<0.01,).药物作用时间为96 h时,0.5g·L-1 OM可明显抑制c-myc,PSM D9,CDK4基因表达(P<0.05,或P<0.01).结论:较低剂量OM显著抑制人结肠癌LoVo细胞增殖的作用机制,可能与下调LoVo细胞c-myc,PSM D9,CDK4表达有关.%Objective: To explore the molecular mechanism of inhibiting colon cancer cell strein LoVo proliferation and inducing apoptosis by oxymatrine ( OM ) Method: Flow cytometry was used to detect the LoVo cells apoptosis and cell cycle distribution. Fluorescence quantitative PCR was used to detect cell proliferation-related genes like the c-myc, proteasome modulator 9 (PSMD9) , CDK4 gene expression when LoVo was treated with 0. 25, 0. 5 g · L-1OM. Result: OM had no significant effect on apoptosis in colon cancer LoVo cells when the treatment of OM lasted 48 h and the concentration was lower than 0.5, 0.25 g · L-1 OM can inhibit c-myc gene expression in LoVo when duration of action last 24 h ( P < 0. 05 ). When the dose increated to 0. 5 g · L-1 and duration of action was 48 h, OM could inhibit c-myc, CDK4 gene expression in LoVo cells (P <0. 01 , P < 0. 01). When duration of action was extended to 96 h, 0. 5 g · L-1 OM could inhibit the c-myc, PSMD9, CDK4 gene expression in LoVo cells ( P < 0. 05, P < 0. 01, P < 0. 01 ). Conclusion; OM at Lower dose could significantly inhibit the proliferation of human colon cancer Lo

  6. A proteomic study of cMyc improvement of CHO culture

    Directory of Open Access Journals (Sweden)

    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.

  7. Investigation of multivalent interactions between conjugate of quantum dots with c-Myc peptide tag and the anti-c-Myc antibody by capillary electrophoresis with fluorescence detection.

    Science.gov (United States)

    Wang, Jianhao; Yang, Li; Liu, Li; Wu, Hao; Wang, Jianpeng; Jiang, Pengju; Jiang, Xiyuan; Qiu, Lin

    2016-12-01

    Herein, we report an assay for detecting the binding of a multivalent peptide and antibody within a capillary with the use of fluorescence coupled capillary electrophoresis. Quantum dots and a c-Myc tag containing peptide EQKLISEEDLG4 H6 were injected sequentially and formed a multivalent quantum dot-EQKLISEEDLG4 H6 assembly within the capillary. The efficiency of the quantum dot-peptide self-assembly was affected by the peptide/quantum dot molar ratio, sampling time, and interval time. Finally, the binding of the monoclonal anti-c-Myc antibody and the multivalent quantum dot-EQKLISEEDLG4 H6 ligand was studied using an in-capillary assay. The microscopic dissociation constant for the self-assembly of monoclonal anti-c-Myc antibody and quantum dot-EQKLISEEDLG4 H6 was determined to be 14.1 μM with a stoichiometry of the peptide-antibody complex of 1.7 determined after fitting this to the Hill equation. This method can be further extended to detect a wide range of biomolecule-biomolecule binding interactions.

  8. Cyclin D1 inhibits whereas c-Myc enhances the cytotoxicity of cisplatin in mouse pancreatic cancer cells via regulation of several members of the NF-κB and Bcl-2 families

    Directory of Open Access Journals (Sweden)

    Ayman El-Kady

    2011-01-01

    Full Text Available Background: Cisplatin (CDDP is a drug used for treatment of many types of malignancy but pancreatic cancer is relatively resistant to it. This study aims to determine whether and how cyclin D1 (D1 and c-Myc influence the response of pancreatic cancer cells to CDDP. Materials and Methods: Ela-mycPT mouse pancreatic cancer cells were transfected with D1 or c-myc cDNA and treated with CDDP alone or together with NPCD, an inhibitor of cyclin dependent ckinase (CDK 4 and 6. Reverse transcription followed by polymerase chain reaction (RT-PCR and western blot assays were used to determine the mRNA and protein levels of interested genes. Cell viability was determined using 3-(4, 5-Dimethylthiazol-2-yl-2, 5-diphenyltetrazolium bromide (MTT assay. Results: Treatment of Ela-mycPT1 cells with CDDP caused an increase in c-myc expression but a slightly latent decrease in D1 expression, whereas D1 and c-Myc proteins repressed each other. D1 or c-Myc rendered Ela-mycPT1 cells resistant or sensitive, respectively, to CDDP. D1 induced the expression of several members of the NF-κB family, including RelA, RelB, Nfκb1 and Nfκb2. D1 also induced BIRC5 and several pro-survival members of the Bcl-2 gene family, including Bcl-2, Mcl-1 and Bad while it decreased the level of the pro-apoptotic Noxa. Inhibition of CDK4 or CDK6 kinase activity by NPCD did not affect these effects of D1. In contrast, c-Myc in Ela-mycPT1 and Ela-mycPT4 cells has the opposite effects to D1 on the expression of most of these apoptosis regulating genes. Conclusion: Our results suggest that induction of c-Myc and inhibition of D1 may be mechanisms for CDDP to elicit cytotoxicity. On the other hand, D1 induces whereas c-Myc represses the expression of key NF-κB family members to induce and repress, respectively, the expression of BIRC5 and several Bcl-2 family members, in turn inhibiting or enhancing the response to CDDP.

  9. MiR-503 inhibited cell proliferation of human breast cancer cells by suppressing CCND1 expression.

    Science.gov (United States)

    Long, Jianting; Ou, Caiwen; Xia, Haoming; Zhu, Yifan; Liu, Dayue

    2015-11-01

    Breast cancer is one of the most common malignancies and a major cause of cancer-related mortality all over the world. A growing body of reports revealed that microRNAs play essential roles in the progression of cancers. Aberrant expression of miR-503 has been reported in several kinds of cancer. The aim of the current study was to elucidate the role of miR-503 in the pathogenesis of breast cancer. In the present study, our results suggested that miR-503 expression was markedly downregulated in breast cancer tissues and cells. Overexpression of miR-503 in breast cancer cell lines reduced cell proliferation through inducing G0/G1 cell cycle arrest by targeting CCND1. Together, our findings provide new knowledge regarding the role of miR-503 in the progression of breast cancer and indicate the role of miR-503 as a tumor suppressor microRNA (miRNA) in breast cancer.

  10. A regulatory loop involving miR-22, Sp1, and c-Myc modulates CD147 expression in breast cancer invasion and metastasis.

    Science.gov (United States)

    Kong, Ling-Min; Liao, Cheng-Gong; Zhang, Yang; Xu, Jing; Li, Yu; Huang, Wan; Zhang, Yi; Bian, Huijie; Chen, Zhi-Nan

    2014-07-15

    Breast cancer is the most common cancer in women for which the metastatic process is still poorly understood. CD147 is upregulated in breast cancer and has been associated with tumor progression, but little is known about its regulatory mechanisms. In this study, we demonstrated that CD147 was overexpressed in breast cancer tissues and cell lines, and the high expression correlated with tumor invasion and metastasis. We also found that the transcription factors Sp1 and c-Myc could bind to the CD147 promoter and enhance its expression. The CD147 mRNA has a 748-bp 3'-untranslated region (UTR) with many miRNA target sites, suggesting possible regulation by miRNAs. We discovered that miR-22 repressed CD147 expression by directly targeting the CD147 3'UTR. We also determined that miR-22 could indirectly participate in CD147 modulation by downregulating Sp1 expression. miR-22 could form an autoregulatory loop with Sp1, which repressed miR-22 transcription by binding to the miR-22 promoter. Together with the c-Myc-mediated inhibition of miR-22 expression, our investigation identified a miR-22/Sp1/c-Myc network that regulates CD147 gene transcription. In addition, miR-22 overexpression suppressed breast cancer cell invasion, metastasis, and proliferation by targeting CD147 in vitro and in vivo. Furthermore, we found that miR-22 was significantly downregulated in breast cancer tissues and that its expression was inversely correlated with the tumor-node-metastasis stage and lymphatic metastasis in patients. Our study provides the first evidence that an miR-22/Sp1/c-Myc network regulates CD147 upregulation in breast cancer and that miR-22 represses breast cancer invasive and metastatic capacities.

  11. 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.

  12. c-myc but not Hif-1α-dependent downregulation of VEGF influences the proliferation and differentiation of HL-60 cells induced by ATRA.

    Science.gov (United States)

    Song, Guanhua; Li, Yanmei; Zhang, Zhiyong; Ren, Xia; Li, Hongjiang; Zhang, Wen; Wei, Ruoying; Pan, Sufei; Shi, Lulu; Bi, Kehong; Jiang, Guosheng

    2013-06-01

    Vascular endothelial growth factor (VEGF) plays an important role in solid tumor growth, progression and metastasis as well as in the proliferation and differentiation of hematological malignancies. However, the molecular mechanism that modulates VEGF expression and secretion in leukemia cells has not yet to be elucidated. The purpose of the present study was to investigate the role of the signal pathway in modulating the expression of VEGF in HL-60 cells. Specific siRNAs targeting VEGF were transfected into HL-60 cells and the VEGF expression was measured with reverse transcription-polymerase chain reaction (RT-PCR) and western blot assay. The cell proliferation of HL-60 cells was detected by the cell counting kit-8 (CCK-8) assay and the differentiation of HL-60 cells induced by all-trans-retinoic acid (ATRA) was detected by the RT-PCR assay and flow cytometry assay for CD11b. The upstream transcription factors that were related to VEGF expression such as P53, SP-1, c-jun, VHL, cox-2, c-myc and stat3 were detected by RT-PCR assay. In addition, the chromatin immunoprecipitation (ChIP) assay was used to reveal the role of c-myc by binding the target gene VEGF. The results demonstrated the hypoxia-inducible factor 1α-related signaling pathway, not the same as in solid tumors, might not play a key role in modulating VEGF expression. c-myc contributes to the modulation of VEGF expression by targeting the promoter of VEGF, which was indicated by the ChIP assay. In conclusion, our data demonstrate that VEGF plays an important role in the differentiation and proliferation of HL-60 cells; c-myc-dependent downregulation of VEGF induced by ATRA contributes to the differentiation of HL-60 cells.

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

    Science.gov (United States)

    Wang, Zhaojing; Xu, Yonghong; Meng, Xiangning; Watari, Fumio; Liu, Hudan; Chen, Xiao

    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.

  14. Abrupt reduction of c-myc expression by antisense RNA inducing terminal differentiation and apoptosis of a human esophageal cancer cell line

    Institute of Scientific and Technical Information of China (English)

    赵晓航; 王秀琴; 周传农; 彭仁玲; 阎水中; 吴旻

    1995-01-01

    A human esophageal cancer cell line (EC8712) expressing high-level Myc protein was infected with recombmant retroviral particles (pA-BD9) at a multiplicity of infection (MOI) 1:1. This viral particle contains a neomycin-resistant gene and a 1.53-kb antisense RNA spanning the 2nd exon and its flanking sequences of the human c-myc oncogene. The G418-resistant EC8712 clones showed an 86% inhibition of growth rate and morphological changes characteristic of terminal differentiation and apoptosis. A decrease of about 80% of Myc protein was also observed in these infected cells by ABC-ELISA assay. 12-24 h after the infection of ECS712 cells with pA-BD9 at a high viral particle concentration (MOI = 1:10), the integration of the extrinsic 1.53-kb antisense c-myc fragment into the cancer cell genome was evidenced by the Southern blot analysis. Northern blot analyses showed the expression of this antisense fragment and a decrease of the intrinsic c-myc expression by 74% in comparison with that of the parental EC8

  15. Diet-induced obesity promotes murine gastric cancer growth through a nampt/sirt1/c-myc positive feedback loop.

    Science.gov (United States)

    Li, Hai-Jun; Che, Xiang-Ming; Zhao, Wei; He, Shi-Cai; Zhang, Zheng-Liang; Chen, Rui; Fan, Lin; Jia, Zong-Liang

    2013-11-01

    Obesity increases the risk of gastric cancer and may promote its growth, as was recently demonstrated by our novel in vivo mouse model. However, the underlying mechanisms of this correlation remain unclear. The purpose of this study was to investigate the precise effects of obesity on gastric cancer growth and to elucidate the potential molecular mechanisms. Diet-induced obese mice were insulin-resistant, glucose-intolerant and had high serum visfatin concentration. In the subcutaneous mouse model, tumors were more aggressive in diet-induced obese mice compared with lean mice. Tumor weights showed a significant positive correlation with mouse body weights, as well as serum insulin and visfatin concentrations. Immunohistochemical staining showed that the expression levels of iNampt, Sirt1 and c-MYC proteins were upregulated in the subcutaneous tumors from obese mice compared to those from lean animals. Furthermore, obesity not only prompted significantly murine forestomach carcinoma cell migration, proliferation, but also affected cellular apoptosis and cell cycle by endocrine mechanisms. These were associated with increased expression of the pro-survival nampt/sirt1/c-myc positive feedback loop confirmed by RT-PCR and western blotting. These results suggested that diet-induced obesity could promote murine gastric cancer growth by upregulating the expression of the nampt, sirt1 and c-myc genes.

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

    Science.gov (United States)

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

    2015-02-01

    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.

  17. cMyc Regulates the Size of the Premigratory Neural Crest Stem Cell Pool.

    Science.gov (United States)

    Kerosuo, Laura; Bronner, Marianne E

    2016-12-06

    The neural crest is a transient embryonic population that originates within the central nervous system (CNS) and then migrates into the periphery and differentiates into multiple cell types. The mechanisms that govern neural crest stem-like characteristics and self-renewal ability are poorly understood. Here, we show that the proto-oncogene cMyc is a critical factor in the chick dorsal neural tube, where it regulates the size of the premigratory neural crest stem cell pool. Loss of cMyc dramatically decreases the number of emigrating neural crest cells due to reduced self-renewal capacity, increased cell death, and shorter duration of the emigration process. Interestingly, rather than via E-Box binding, cMyc acts in the dorsal neural tube by interacting with another transcription factor, Miz1, to promote self-renewal. The finding that cMyc operates in a non-canonical manner in the premigratory neural crest highlights the importance of examining its role at specific time points and in an in vivo context.

  18. Dose-adjusted Chemotherapy for Untreated c-MYC-positive Lymphoma

    Science.gov (United States)

    In this trial, adult patients with newly diagnosed Burkitt lymphoma or c-MYC-positive DLBCL will be separated into low-risk and high-risk groups; those in the low-risk group will be treated with at least three cycles of dose-adjusted EPOCH-R

  19. 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.

  20. Sensitivity of nuclear c-myc levels and induction to differentiation-inducing agents in human colon tumor cell lines.

    Science.gov (United States)

    Taylor, C W; Kim, Y S; Childress-Fields, K E; Yeoman, L C

    1992-02-29

    Six human colon tumor cell lines were analyzed for their constitutive levels of the c-myc protein. The nuclear proto-oncogene, c-myc, was detected as an expressed product in all of the human colon tumor cell lines analyzed. The poorly differentiated cell lines HCT116, RKO and C showed c-myc levels that averaged 2-fold greater than their well-differentiated counterparts, i.e., GEO, CBS and FET. When c-myc levels and responses to serum induction were analyzed in the presence of inducers of differentiation, i.e., dimethylformamide, retinoic acid, sodium butyrate and TGF-beta, distinct patterns of sensitivity and resistance emerged. Nuclear c-myc levels were reduced in all the colon cell phenotypes treated with dimethylformamide or sodium butyrate. Only the well-differentiated human colon tumor cell lines were responsive to transforming growth factor-beta. Only one of the human colon tumor cell lines (GEO) responded to retinoic acid. Increased levels of c-myc protein were found to correlate well with greater growth rates and with poor differentiation class. Similarly, a parallel sensitivity to down-regulation of c-myc levels and attenuation of c-myc induction curves for inducers of differentiation were observed in growth sensitive human colon tumor cell lines.

  1. c-Myc is a novel target of cell cycle arrest by honokiol in prostate cancer cells.

    Science.gov (United States)

    Hahm, Eun-Ryeong; Singh, Krishna Beer; Singh, Shivendra V

    2016-09-01

    Honokiol (HNK), a highly promising phytochemical derived from Magnolia officinalis plant, exhibits in vitro and in vivo anticancer activity against prostate cancer but the underlying mechanism is not fully clear. This study was undertaken to delineate the role of c-Myc in anticancer effects of HNK. Exposure of prostate cancer cells to plasma achievable doses of HNK resulted in a marked decrease in levels of total and/or phosphorylated c-Myc protein as well as its mRNA expression. We also observed suppression of c-Myc protein in PC-3 xenografts upon oral HNK administration. Stable overexpression of c-Myc in PC-3 and 22Rv1 cells conferred significant protection against HNK-mediated growth inhibition and G0-G1 phase cell cycle arrest. HNK treatment decreased expression of c-Myc downstream targets including Cyclin D1 and Enhancer of Zeste Homolog 2 (EZH2), and these effects were partially restored upon c-Myc overexpression. In addition, PC-3 and DU145 cells with stable knockdown of EZH2 were relatively more sensitive to growth inhibition by HNK compared with control cells. Finally, androgen receptor overexpression abrogated HNK-mediated downregulation of c-Myc and its targets particularly EZH2. The present study indicates that c-Myc, which is often overexpressed in early and late stages of human prostate cancer, is a novel target of prostate cancer growth inhibition by HNK.

  2. The reducing agent Dithiothreitol (DTT) increases expression of c-myc and c- fos protooncogenes in human cells

    DEFF Research Database (Denmark)

    Skouv, J.; Sørensen, Ilona Kryspin; Frandsen, H.

    1995-01-01

    The objective of the present study was to assess the possible tumour promoting activity of the food mutagen 2-hydroxyamino-1-methyl-6-phenylimidazo[4,5-b]pyridine (N-OH-PhIP), by studying its influence on the expression of three genes considered to be of relevance in the tumour promotion step....... However, when cells were treated with DTT alone, the expression of c-fos and c-myc was also transiently induced. We therefore conclude that DTT, and not N-OH-PhIP, induced oncogene expression. Induction of both c-fos and c-mye expression by a reducing agent, DTT, which is frequently used in in vitro...

  3. C-Myc regulates substrate oxidation patterns during early pressure-overload hypertrophy

    Energy Technology Data Exchange (ETDEWEB)

    Ledee, Dolena R. [Seattle Children' s Research Inst., Seattle, WA (United States); Smith, Lincoln [Seattle Children' s Hospital, Seattle, WA (United States); Kajimoto, Masaki [Seattle Children' s Research Inst., Seattle, WA (United States); Bruce, Margaret [Seattle Children' s Research Inst., Seattle, WA (United States); Isern, Nancy G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL); Xu, Chun [Seattle Children' s Research Inst., Seattle, WA (United States); Portman, Michael A. [Seattle Children' s Research Inst., Seattle, WA (United States); Olson, Aaron [Seattle Children' s Research Inst., Seattle, WA (United States)

    2013-11-26

    Pressure overload cardiac hypertrophy alters substrate metabolism. Prior work showed that myocardial inactivation of c-Myc (Myc) attenuated hypertrophy and decreased expression of glycolytic genes after aortic constriction. Accordingly, we hypothesize that Myc regulates substrate preferences for the citric acid cycle during pressure overload hypertrophy from transverse aortic constriction (TAC) and that these metabolic changes impact cardiac function and growth. To test this hypothesis, we subjected FVB mice with cardiac specific, inducible Myc inactivation (MycKO-TAC) and non-transgenic littermates (Cont-TAC) to transverse aortic constriction (n=7/group). A separate group underwent sham surgery (Sham, n=5). After two weeks, function was measured in isolated working hearts along with substrate fractional contributions to the citric acid cycle by using perfusate with 13C labeled mixed fatty acids, lactate, ketones and unlabeled glucose and insulin. Western blots were used to evaluate metabolic enzymes. Cardiac function was similar between groups after TAC although +dP/dT and -dP/dT trended towards improvement in MycKO-TAC versus Cont-TAC. Compared to Sham, Cont-TAC had increased free fatty acid fractional contribution with a concurrent decrease in unlabeled (presumably glucose) contribution. Myc inactivation (MycKO-TAC) inhibited these metabolic changes. Hypertrophy in general increased protein levels of PKM2; however this change was not linked to Myc status. Protein post-translation modification by O-GlcNAc was significantly greater in Cont-TAC versus both Sham and MycKO-TAC. In conclusion, Myc regulates substrate utilization during early pressure overload hypertrophy. Our results show that the metabolic switch during hypertrophy is not necessary to maintain cardiac function, but it may be important mechanism to promote cardiomyocyte growth. Myc also regulates protein O-GlcNAcylation during hypertrophy.

  4. Oncogene amplification detected by in situ hybridization in radiation induced rat skin tumors. [C-myc:a3

    Energy Technology Data Exchange (ETDEWEB)

    Yi Jin.

    1991-02-01

    Oncogene activation may play an important role in radiation induced carcinogenesis. C-myc oncogene amplification was detected by in situ hybridization in radiation-induced rat skin tumors, including squamous and basal cell carcinomas. In situ hybridization was performed with a biotinylated human c-myc third exon probe, visualized with an avidin-biotinylated alkaline phosphate detection system. No c-myc oncogene amplification was detected in normal rat skin at very early times after exposure to ionizing radiation, which is consistent with the view that c-myc amplification is more likely to be related to carcinogenesis than to normal cell proliferation. The incorporation of tritiated thymidine into the DNA of rat skin cells showed that the proliferation of epidermal cells reached a peak on the seventh day after exposure to ionizing radiation and then decreased. No connection between the proliferation of epidermal cell and c-myc oncogene amplification in normal or irradiated rat skin was found. The results indicated that c-myc amplification as measured by in situ hybridization was correlated with the Southern bolt results, but only some of the cancer cells were amplified. The c-myc positive cells were distributed randomly within regions of the tumor and exhibited a more uniform nuclear structure in comparison to the more vacuolated c-myc negative cells. No c-myc signal was detected in unirradiated normal skin or in irradiated skin cells near the tumors. C-myc amplification appears to be cell or cell cycle specific within radiation-induced carcinomas. 28 refs., 3 figs., 3 tabs.

  5. Genomic imbalances in esophageal carcinoma cell lines involve Wnt pathway genes

    Institute of Scientific and Technical Information of China (English)

    Jacqueline Brown; Hannelie Bothma; Robin Veale; Pascale Willem

    2011-01-01

    AIM: To identify molecular markers shared across South African esophageal squamous cell carcinoma (ESCC) cell lines using cytogenetics, fluorescence in situ hybridization (FISH) and single nucleotide polymorphism (SNP) array copy number analysis. METHODS: We used conventional cytogenetics, FISH, and multicolor FISH to characterize the chromosomal rearrangements of five ESCC cell lines established in South Africa. The whole genome copy number profile was established from 250K SNP arrays, and data was analyzed with the CNAT 4.0 and GISTIC software. RESULTS: We detected common translocation breakpoints involving chromosomes 1p11-12 and 3p11.2, the latter correlated with the deletion, or interruption of the EPHA3 gene. The most significant amplifications involved the following chromosomal regions and genes: 11q13.3 ( CCND1, FGF3, FGF4, FGF19, MYEOV), 8q24.21( C-MYC, FAM84B), 11q22.1-q22.3 ( BIRC2, BIRC3), 5p15.2 ( CTNND2), 3q11.2-q12.2 ( MINA) and 18p11.32 ( TYMS, YES1). The significant deletions included 1p31.2-p31.1 ( CTH, GADD45α, DIRAS3), 2q22.1 ( LRP1B), 3p12.1-p14.2 ( FHIT), 4q22.1-q32.1 ( CASP6, SMAD1), 8p23.2-q11.1 ( BNIP3L) and 18q21.1-q21.2 ( SMAD4, DCC). The 3p11.2 translocation breakpoint was shared across four cell lines, supporting a role for genes involved at this site, in particular, the EPHA3 gene which has previously been reported to be deleted in ESCC. CONCLUSION: The finding that a significant number of genes that were amplified (FGF3 , FGF4 , FGF19 , CCND1 and C-MYC ) or deleted (SFRP2 gene) are involved in the Wnt and fibroblast growth factor signaling pathways, suggests that these pathways may be activated in these cell lines.

  6. Alterations in TP53, cyclin D2, c-Myc, p21WAF1/CIP1 and p27KIP1 expression associated with progression in B-CLL

    Directory of Open Access Journals (Sweden)

    Antosz Halina

    2010-04-01

    Full Text Available B-cell chronic lymphocytic leukaemia (B-CLL originates from B lymphocytes that may differ in the activationlevel, maturation state or cellular subgroups in peripheral blood. Tumour progression in CLL B cells seems to result in gradualaccumulation of the clone of resting B lymphocytes in the early phases (G0/G1 of the cell cycle. The G1 phase isimpaired in B-CLL. We investigated the gene expression of five key cell cycle regulators: TP 53, c-Myc, cyclin D2,p21WAF1/CIP1 and p27KIP1, which primarily regulate the G1 phase of the cell cycle, or S-phase entry and ultimately controlthe proliferation and cell growth as well as their role in B-CLL progression. The study was conducted in peripheral bloodCLL lymphocytes of 40 previously untreated patients. Statistical analysis of correlations of TP53, cyclin D2, c-Myc,p21WAF1/CIP1 and p27KIP1 expressions in B-CLL patients with different Rai stages demonstrated that the progression of diseasewas accompanied by increases in p53, cyclin D2 and c-Myc mRNA expression. The expression of p27KIP1 was nearlystatistically significant whereas that of p21 WAF1/CIP1 showed no such correlation. Moreover, high expression levels of TP53and c-Myc genes were found to be closely associated with more aggressive forms of the disease requiring earlier therapy.

  7. The effect of non-coding DNA variations on P53 and cMYC competitive inhibition at cis-overlapping motifs.

    Science.gov (United States)

    Kin, Katherine; Chen, Xi; Gonzalez-Garay, Manuel; Fakhouri, Walid D

    2016-04-15

    Non-coding DNA variations play a critical role in increasing the risk for development of common complex diseases, and account for the majority of SNPs highly associated with cancer. However, it remains a challenge to identify etiologic variants and to predict their pathological effects on target gene expression for clinical purposes. Cis-overlapping motifs (COMs) are elements of enhancer regions that impact gene expression by enabling competitive binding and switching between transcription factors. Mutations within COMs are especially important when the involved transcription factors have opposing effects on gene regulation, like P53 tumor suppressor and cMYC proto-oncogene. In this study, genome-wide analysis of ChIP-seq data from human cancer and mouse embryonic cells identified a significant number of putative regulatory elements with signals for both P53 and cMYC. Each co-occupied element contains, on average, two COMs, and one common SNP every two COMs. Gene ontology of predicted target genes for COMs showed that the majority are involved in DNA damage, apoptosis, cell cycle regulation, and RNA processing. EMSA results showed that both cMYC and P53 bind to cis-overlapping motifs within a ChIP-seq co-occupied region in Chr12. In vitro functional analysis of selected co-occupied elements verified enhancer activity, and also showed that the occurrence of SNPs within three COMs significantly altered enhancer activity. We identified a list of COM-associated functional SNPs that are in close proximity to SNPs associated with common diseases in large population studies. These results suggest a potential molecular mechanism to identify etiologic regulatory mutations associated with common diseases.

  8. 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}.

  9. Perinucleolar relocalization and nucleolin as crucial events in the transcriptional activation of key genes in mantle cell lymphoma.

    Science.gov (United States)

    Allinne, Jeanne; Pichugin, Andrei; Iarovaia, Olga; Klibi, Manel; Barat, Ana; Zlotek-Zlotkiewicz, Ewa; Markozashvili, Diana; Petrova, Natalia; Camara-Clayette, Valérie; Ioudinkova, Elena; Wiels, Joëlle; Razin, Sergey V; Ribrag, Vincent; Lipinski, Marc; Vassetzky, Yegor S

    2014-03-27

    In mantle cell lymphoma (MCL), one allele of the cyclin D1 (Ccnd1) gene is translocated from its normal localization on chromosome 11 to chromosome 14. This is considered as the crucial event in the transformation process of a normal naive B-cell; however, the actual molecular mechanism leading to Ccnd1 activation remains to be deciphered. Using a combination of three-dimensional and immuno-fluorescence in situ hybridization experiments, the radial position of the 2 Ccnd1 alleles was investigated in MCL-derived cell lines and malignant cells from affected patients. The translocated Ccnd1 allele was observed significantly more distant from the nuclear membrane than its nontranslocated counterpart, with a very high proportion of IgH-Ccnd1 chromosomal segments localized next to a nucleolus. These perinucleolar areas were found to contain active RNA polymerase II (PolII) clusters. Nucleoli are rich in nucleolin, a potent transcription factor that we found to bind sites within the Ccnd1 gene specifically in MCL cells and to activate Ccnd1 transcription. We propose that the Ccnd1 transcriptional activation in MCL cells relates to the repositioning of the rearranged IgH-Ccnd1-carrying chromosomal segment in a nuclear territory with abundant nucleolin and active PolII molecules. Similar transforming events could occur in Burkitt and other B-cell lymphomas.

  10. 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

    in the ventricular zone and, analogous to human glioblastomas, exhibit molecular and morphological heterogeneity. Levels of connexin 43 in the majority of the tumors are unaltered from normal tissue, indicating that GEM tumors have retained the capacity to establish syncytial networks. In line with this, individual...... 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....

  11. Targeting of the MYCN protein with small molecule c-MYC inhibitors.

    Directory of Open Access Journals (Sweden)

    Inga Müller

    Full Text Available 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 tumors. Since patients with MYCN-amplified neuroblastoma have a poor prognosis, targeting MYCN using small molecule inhibitors could represent a promising therapeutic approach. We have previously demonstrated that the small molecule 10058-F4, known to bind to the c-MYC bHLHZip dimerization domain and inhibiting the c-MYC/MAX interaction, also interferes with the MYCN/MAX dimerization in vitro and imparts anti-tumorigenic effects in neuroblastoma tumor models with MYCN overexpression. Our previous work also revealed that MYCN-inhibition leads to mitochondrial dysfunction resulting in accumulation of lipid droplets in neuroblastoma cells. To expand our understanding of how small molecules interfere with MYCN, we have now analyzed the direct binding of 10058-F4, as well as three of its analogs; #474, #764 and 10058-F4(7RH, one metabolite C-m/z 232, and a structurally unrelated c-MYC inhibitor 10074-G5, to the bHLHZip domain of MYCN. We also assessed their ability to induce apoptosis, neurite outgrowth and lipid accumulation in neuroblastoma cells. Interestingly, all c-MYC binding molecules tested also bind MYCN as assayed by surface plasmon resonance. Using a proximity ligation assay, we found reduced interaction between MYCN and MAX after treatment with all molecules except for the 10058-F4 metabolite C-m/z 232 and the non-binder 10058-F4(7RH. Importantly, 10074-G5 and 10058-F4 were the most efficient in inducing neuronal differentiation and lipid accumulation in MYCN-amplified neuroblastoma cells. Together our data demonstrate MYCN-binding properties for a selection of small molecules, and provide functional information that could be of importance for future development of targeted therapies against MYCN-amplified neuroblastoma.

  12. Ruthenium(II) complexes as apoptosis inducers by stabilizing c-myc G-quadruplex DNA.

    Science.gov (United States)

    Zhang, Zhao; Wu, Qiong; Wu, Xiao-Hui; Sun, Fen-Yong; Chen, Lan-Mei; Chen, Jin-Chan; Yang, Shu-Ling; Mei, Wen-Jie

    2014-06-10

    Two ruthenium(II) complexes, [Ru(L)2(p-tFMPIP)](ClO4)2 (L = bpy, 1; phen, 2; p-tFMPIP = 2-(4-(trifluoromethyphenyl)-1H-imidazo[4,5f][1,10] phenanthroline)), were prepared by microwave-assisted synthesis technology. The inhibitory activity evaluated by MTT assay shown that 2 can inhibit the growth of MDA-MB-231 cells with inhibitory activity (IC50) of 16.3 μM, which was related to the induction of apoptosis. Besides, 2 exhibit low toxicity against normal HAcat cells. The inhibitory growth activity of both complexes related to the induction of apoptosis was also confirmed. Furthermore, the studies on the interaction of both complexes with c-myc G4 DNA shown that 1 and 2 can stabilize the conformation of c-myc G4 DNA in groove binding mode, which has been rational explained by using DFT theoretical calculation methods. In a word, this type of ruthenium(II) complexes can act as potential apoptosis inducers with low toxicity in clinic by stabilizing c-myc G4 DNA.

  13. c-myc and N-myc promote active stem cell metabolism and cycling as architects of the developing brain.

    Science.gov (United States)

    Wey, Alice; Knoepfler, Paul S

    2010-06-01

    myc genes are associated with a wide variety of human cancers including most types of nervous system tumors. While the mechanisms by which myc overexpression causes tumorigenesis are multifaceted and have yet to be clearly elucidated, they are at least in part related to endogenous myc function in normal cells. Knockout (KO) of either c-myc or N-myc genes in neural stem and precursor cells (NSC) driven by nestin-cre impairs mouse brain growth and mutation of N-myc also causes microcephaly in humans in Feingold Syndrome. To further define myc function in NSC and nervous system development, we created a double KO (DKO) for c- and N-myc using nestin-cre. The DKO mice display profoundly impaired overall brain growth associated with decreased cell cycling and migration of NSC, which are strikingly decreased in number. The DKO brain also exhibits specific changes in gene expression including downregulation of genes involved in protein and nucleotide metabolism, mitosis, and chromatin structure as well as upregulation of genes associated with differentiation. Together these data support a model of nervous system tumorigenesis in which excess myc aberrantly locks in a developmentally active chromatin state characterized by overactive cell cycling, and metabolism as well as blocked differentiation.

  14. 阴道脱落细胞检查联合人类染色体末端酶基因、c-myc 检测在宫颈癌诊断中的价值%The clinical value of Thinprep cytology test combined with h -TERC and c -myc in the diagnosis of cervical ;cancer

    Institute of Scientific and Technical Information of China (English)

    毛海波

    2015-01-01

    Objective To explore the clinical value of Thinprep cytology test (TCT)combined with h -TERC and c -myc in the diagnosis of cervical cancer.Methods hTERC amplification was detected by dual -color interphase fluorescence in situ hybridization (FISH),and the results were compared with TCT and histological examination.Examination the positive which TCT,h -TERC and c -myc by pathological examination.The final diag-nosis was determined by the pathological examination.Results TCT was abnormal in 26.4% of 500 case,18.0%abnormal h -TERC gene,16.0% abnormal c -myc gene.In 270 cases according to the cervical biopsy,the positive rate of chronic inflammation,cervical intraepithelial neoplasia (CIN)Ⅰ,CINⅡ,CINⅢ and cervical cancer:44.4%, 38.2%,36.4%,18.2%,and 7.3% respectively.The positive rates of h -TERC were 18.1%,45.4%,52.5%, 65.9% and 100.0%,respectively.The positive rates of c -myc were 21.4%,48.9%,56.7%,59.9% and 100.0%.With increased pathological grade,the expressions of h -TERC and c -myc were high.Conclusion TCT combined with h -TERC and c -myc can test cervical cancer more effective.%目的:探讨阴道脱落细胞检查(TCT)结合人类染色体末端酶基因(h-TERC)和 c-myc 检测在宫颈癌中的价值。方法运用免疫荧光原位杂交技术检测近三年来该院宫颈癌患者500例的宫颈脱落细胞中h-TERC 和 c-myc 的表达,将其检测结果与 TCT 检测结果比较,将上述三种结果的任一阳性检测再进行病理学诊断标准来确定,且以病理诊断为准进行分析。结果在所检测的500例患者中,TCT 异常者132例(26.4%),h-TECR 异常者90例(18.0%),c-myc 异常者80例(16.0%),将270例患者进行阴道宫颈活检技术,在这些病例中,宫颈慢性炎者120例,宫颈病变者150例,其中宫颈上皮瘤变 CINⅠ52例(38.2%),CINⅡ50例(36.4%),CIN Ⅲ30例(18.2%),宫颈癌18例(7.3%)。在所检测的病例中,

  15. An Epigenetic Pathway Regulates Sensitivity of Breast Cancer Cells to HER2 Inhibition via FOXO/c-Myc Axis

    Science.gov (United States)

    Matkar, Smita; Sharma, Paras; Gao, Shubin; Gurung, Buddha; Katona, Bryson W; Liao, Jennifer; Muhammad, Abdul Bari; Kong, Xiang-Cheng; Wang, Lei; Jin, Guanghui; Dang, Chi; Hua, Xianxin

    2016-01-01

    SUMMARY Human epidermal growth factor receptor 2 (HER2) is upregulated in a subset of human breast cancers. However, the cancer cells often quickly develop an adaptive response to HER2 kinase inhibitors. We found that an epigenetic pathway involving MLL2 is crucial for growth of HER2+ cells and MLL2 reduces sensitivity of the cancer cells to a HER2 inhibitor, Lapatinib. Lapatinib-induced FOXO transcription factors, normally tumor-suppressing, paradoxically upregulate c-Myc epigenetically, in concert with a cascade of MLL2-associating epigenetic regulators, to dampen sensitivity of the cancer cells to Lapatinib. An epigenetic inhibitor suppressing c-Myc synergizes with Lapatinib to suppress cancer growth in vivo, partly by repressing the FOXO/c-Myc axis, unraveling an epigenetically regulated FOXO/c-Myc axis as a potential target to improve therapy. PMID:26461093

  16. Prognostic Value of Beta-Tubulin-3 and c-Myc in Muscle Invasive Urothelial Carcinoma of the Bladder

    Science.gov (United States)

    Massari, Francesco; Bria, Emilio; Ciccarese, Chiara; Munari, Enrico; Modena, Alessandra; Zambonin, Valentina; Sperduti, Isabella; Artibani, Walter; Cheng, Liang; Martignoni, Guido; Tortora, Giampaolo; Brunelli, Matteo

    2015-01-01

    Background To date, putative prognostic biomarkers have shown limited utility from the clinical perspective for bladder urothelial carcinoma. Herein, the expression of beta-tubulin-3 and c-Myc was evaluated to determine their prognostic potential. Methods In formalin fixed-paraffin embedded blocks, immunohistochemical expression of c-Myc and beta-tubulin-3 was evaluated. H score ranging from 0 to 300 was obtained by multiplying the percentage of positive cells by intensity (0–3); c-Myc and beta-tubulin-3 expression was defined: 0: negative, 1: weakly positive, 2: strongly positive. Results beta-tubulin-3 and c-Myc immunoexpression was available for 46 cases. At the univariate analysis, node-involvement, beta-tubulin-3 and c-Myc overexpression discriminate shorter DFS (HR 2.19, p = 0.043; HR 3.10, p = 0.24 and HR 3.05, p = 0.011, respectively); 2-yrs DFS log-rank analysis according to low versus high level of immunoexpression were statistically significant; beta-tubulin-3, 53% low vs 12.7% high (p = value 0.02) and c-Myc 28 low vs 8 high (p-value 0.007). Patients displaying negative beta-tubulin-3/c-Myc had statistically significant better 2-yrs DFS than those with mixed expression or double positivity (54.5% versus 18.7% versus 0%, log-rank p = 0.006). Conclusions c-Myc and beta-tubulin-3 show improvement for prognostic risk stratification in patients with muscle invasive bladder urothelial carcinoma. These molecular pathways may also be candidate to improve predictiveness to targeted therapies. PMID:26046361

  17. Prognostic Value of Beta-Tubulin-3 and c-Myc in Muscle Invasive Urothelial Carcinoma of the Bladder.

    Directory of Open Access Journals (Sweden)

    Francesco Massari

    Full Text Available To date, putative prognostic biomarkers have shown limited utility from the clinical perspective for bladder urothelial carcinoma. Herein, the expression of beta-tubulin-3 and c-Myc was evaluated to determine their prognostic potential.In formalin fixed-paraffin embedded blocks, immunohistochemical expression of c-Myc and beta-tubulin-3 was evaluated. H score ranging from 0 to 300 was obtained by multiplying the percentage of positive cells by intensity (0-3; c-Myc and beta-tubulin-3 expression was defined: 0: negative, 1: weakly positive, 2: strongly positive.beta-tubulin-3 and c-Myc immunoexpression was available for 46 cases. At the univariate analysis, node-involvement, beta-tubulin-3 and c-Myc overexpression discriminate shorter DFS (HR 2.19, p = 0.043; HR 3.10, p = 0.24 and HR 3.05, p = 0.011, respectively; 2-yrs DFS log-rank analysis according to low versus high level of immunoexpression were statistically significant; beta-tubulin-3, 53% low vs 12.7% high (p = value 0.02 and c-Myc 28 low vs 8 high (p-value 0.007. Patients displaying negative beta-tubulin-3/c-Myc had statistically significant better 2-yrs DFS than those with mixed expression or double positivity (54.5% versus 18.7% versus 0%, log-rank p = 0.006.c-Myc and beta-tubulin-3 show improvement for prognostic risk stratification in patients with muscle invasive bladder urothelial carcinoma. These molecular pathways may also be candidate to improve predictiveness to targeted therapies.

  18. hTERT protein expression is independent of clinicopathological parameters and c-Myc protein expression in human breast cancer

    Directory of Open Access Journals (Sweden)

    Meligonis G

    2005-01-01

    Full Text Available Abstract Background Telomerase is a ribonucleoprotein enzyme that synthesises telomeres after cell division and maintains chromosomal length and stability thus leading to cellular immortalisation. The hTERT (human telomerase reverse transcriptase subunit seems to be the rate-limiting determinant of telomerase and knowledge of factors controlling hTERT transcription may be useful in therapeutic strategies. The hTERT promoter contains binding sites for c-Myc and there is some experimental and in vitro evidence that c-Myc may increase hTERT expression. We previously reported no correlation between c-Myc mRNA expression and hTERT mRNA or telomerase activity in human breast cancer. This study aims to examine the correlation between hTERT expression as determined by immunohistochemistry and c-Myc expression, lymph node status, and tumour size and grade in human breast cancer. Materials and methods The immunohistochemical expression of hTERT and c-Myc was investigated in 38 malignant breast tumours. The expression of hTERT was then correlated with the lymph node status, c-Myc expression and other clinicopathological parameters of the tumours. Results hTERT expression was positive in 27 (71% of the 38 tumours. 15 (79% of 19 node positive tumours were hTERT positive compared with 11 (63% of 19 node negative tumours. The expression was higher in node positive tumours but this failed to reach statistical significance (p = 0.388. There was no significant association with tumour size, tumour grade or c-Myc expression. However, hTERT expression correlated positively with patients' age (correlation coefficient = 0.415, p = 0.0097. Conclusion hTERT protein expression is independent of lymph node status, tumour size and grade and c-Myc protein expression in human breast cancer

  19. Expressão dos protooncogenes c-fos, c-myc e c-jun em miométrio normal e mioma humanos Expression of the protooncogenes c-fos, c-myc and c-jun in human normal miometrium and leiomyoma

    Directory of Open Access Journals (Sweden)

    Ana Luiza Ferrari

    2006-10-01

    Full Text Available OBJETIVO: Comparar a expressão gênica (mRNA e protéica dos protooncogenes c-fos, c-myc e c-jun em miométrio normal e mioma humanos. MÉTODOS: Foi realizado um estudo do tipo caso-controle. O material foi coletado de 12 pacientes submetidas a histerectomia no Hospital de Clínicas de Porto Alegre. A expressão do mRNA específico para c-myc, c-fos, c-jun e beta-microglobulina foi avaliada pela técnica de RT-PCR, utilizando primers específicos para cada gene. A expressão protéica destes protooncogenes foi avaliada através de Western blot com anticorpos específicos. RESULTADOS: Não houve diferença significativa para expressão gênica desses protooncogenes entre miométrio normal e mioma (c-myc: 0,87 ± 0,08 vs 0,87 ± 0,08, p = 0,952; c-fos: 1,10 ± 0,17 vs 1,01 ± 0,11, p = 0,21; c-jun: 1,03 ± 0,12 vs 0,96 ± 0,09, p = 0,168, respectivamente. Não houve diferença significativa para expressão protéica desses protooncogenes entre miométrio normal e mioma (c-myc: 1,36 ± 0,48 vs 1,53 ± 0,29, p = 0,569; c-fos: 8,85 ± 5,5 vs 6,56 ± 4,22, p = 0,434; e c-jun: 6,47 ± 3,04 vs 5,42 ± 2,03, p = 0,266, respectivamente. CONCLUSÃO: A expressão gênica (transcrição e a expressão protéica (tradução dos protooncogenes c-myc, c-fos e c-jun em mioma e miométrio normal são semelhantes.Uterine myomas are common benign tumors of the female genital tract. The expression of growth factor signal transduction cascade components including the protooncogenes c-myc, c-fos, and c-jun seem to be involved in the development of myomas. PURPOSE: To compare the gene (mRNA and protein expression of the protooncogenes c-fos, c-myc, and c-jun in human normal myometrium and leiomyoma. METHOD: A case-control study was performed. Samples were collected from 12 patients submitted to hysterectomy at the Hospital de Clínicas at Porto Alegre. The expression of the specific mRNA for c-myc, c-fos, c-jun, and beta-microglobulin was assessed through the RT

  20. BAF53 Forms Distinct Nuclear Complexes and Functions as a Critical c-Myc-Interacting Nuclear Cofactor for Oncogenic Transformation

    Science.gov (United States)

    Park, Jeonghyeon; Wood, Marcelo A.; Cole, Michael D.

    2002-01-01

    The c-Myc oncoprotein functions as a transcription factor that can transform normal cells into tumor cells, as well as playing a direct role in normal cell proliferation. The c-Myc protein transactivates cellular promoters by recruiting nuclear cofactors to chromosomal sites through an N-terminal transactivation domain. We have previously reported the identification and functional characterization of four different c-Myc cofactors: TRRAP, hGCN5, TIP49, and TIP48. Here we present the identification and characterization of the actin-related protein BAF53 as a c-Myc-interacting nuclear cofactor that forms distinct nuclear complexes. In addition to the human SWI/SNF-related BAF complex, BAF53 forms a complex with TIP49 and TIP48 and a separate biochemically distinct complex containing TRRAP and a histone acetyltransferase which does not contain TIP60. Using deletion mutants of BAF53, we show that BAF53 is critical for c-Myc oncogenic activity. Our results indicate that BAF53 plays a functional role in c-Myc-interacting nuclear complexes. PMID:11839798

  1. Transient activation of c-MYC expression is critical for efficient platelet generation from human induced pluripotent stem cells.

    Science.gov (United States)

    Takayama, Naoya; Nishimura, Satoshi; Nakamura, Sou; Shimizu, Takafumi; Ohnishi, Ryoko; Endo, Hiroshi; Yamaguchi, Tomoyuki; Otsu, Makoto; Nishimura, Ken; Nakanishi, Mahito; Sawaguchi, Akira; Nagai, Ryozo; Takahashi, Kazutoshi; Yamanaka, Shinya; Nakauchi, Hiromitsu; Eto, Koji

    2010-12-20

    Human (h) induced pluripotent stem cells (iPSCs) are a potentially abundant source of blood cells, but how best to select iPSC clones suitable for this purpose from among the many clones that can be simultaneously established from an identical source is not clear. Using an in vitro culture system yielding a hematopoietic niche that concentrates hematopoietic progenitors, we show that the pattern of c-MYC reactivation after reprogramming influences platelet generation from hiPSCs. During differentiation, reduction of c-MYC expression after initial reactivation of c-MYC expression in selected hiPSC clones was associated with more efficient in vitro generation of CD41a(+)CD42b(+) platelets. This effect was recapitulated in virus integration-free hiPSCs using a doxycycline-controlled c-MYC expression vector. In vivo imaging revealed that these CD42b(+) platelets were present in thrombi after laser-induced vessel wall injury. In contrast, sustained and excessive c-MYC expression in megakaryocytes was accompanied by increased p14 (ARF) and p16 (INK4A) expression, decreased GATA1 expression, and impaired production of functional platelets. These findings suggest that the pattern of c-MYC expression, particularly its later decline, is key to producing functional platelets from selected iPSC clones.

  2. Expression of Wnt-1,beta-catenin and c-myc in Ovarian Epithelial Tumor and Its Implication

    Institute of Scientific and Technical Information of China (English)

    LIN Xiao; HU Zhuo-ying

    2008-01-01

    Objective:To investigate the expression of Wnt-1, beta-catenin and c-myc in normal ovarian epithelial cell and malignant ovarian epithelial tumor. Methods:Immunohistochemical staining with SP method was conducted to identify the expression of Wnt-1,beta-catenin and c-myc in 18 samples of normal epithelial tissue and 34 cases of malignant epithelial tumor of ovary. Results:The expression rate of Wnt-1 and c-myc in malignant epithelial tumors was higher than those in normal epithelial cell(P<0.05).The abnormal expression rate of beta-catenin in malignant ovarian epithelial tumors was higher than that in normal epithelial cell(P<0.05).A significant positive correlation was found between Wnt-1, beta-catenin and c-myc in malignant ovarian epithelial tumor(P<0.05).A significant difierence of expressions of Beta-catenin and C-myc was found between serous and mutinous tumors (P<0.05). Conclusion:The abnormal expression of Wnt-1,beta-catenin and c-myc might indicate the malignant transformation in ovarian epithelial tumors.

  3. Coordinate increase of telomerase activity and c-Myc expression in Helicobacter pylori-associated gastric diseases

    Institute of Scientific and Technical Information of China (English)

    Guo-Xin Zhang; Yan-Hong Gu; Zhi-Quan Zhao; Shun-Fu Xu; Hong-Ji Zhang; Hong-Di Wang; Bo Hao

    2004-01-01

    AIM: To detect the telomerase activity and c-Myc expression in gastric diseases and to examine the relation between these values and Helicobacter pylori (H pylori) as a risk factor for gastric cancer.METHODS: One hundred and seventy-one gastric samples were studied to detect telomerase activity using a telomerase polymerase chain reaction enzyme linked immunosorbent assay (PCR-ELTSA), and c-Myc expression using immunohistochemistry.RESULTS: The telomerase activity and c-Myc expression were higher in cancers (87.69% and 61.54%) than in noncancerous tissues. They were higher in chronic atrophic gastritis with severe intestinal metaplasia (52.38% and 47.62%) than in chronic atrophic gastritis with mild intestinal metaplasia (13.33% and 16.67%). Tn chronic atrophic gastritis with severe intestinal metaplasia, the telomerase activity and c-Myc expression were higher in cases with -H pylori infection (67.86% and 67.86%) than in those without infection (21.43%and 7.14%). c-Myc expression was higher in gastric cancer with H pylori infection (77.27%) than in that without infection (28.57%). The telomerase activity and c-Nyc expression were coordinately up-regulated in H pylori infected gastric cancer and chronic atrophic gastritis with severe intestinal metaplasia.CONCLUSION: H pylori infection may influence both telomerase activity and c-Myc expression in gastric diseases,especially in chronic atrophic gastritis.

  4. AID induces double-strand breaks at immunoglobulin switch regions and c-MYC causing chromosomal translocations in yeast THO mutants.

    Science.gov (United States)

    Ruiz, José F; Gómez-González, Belén; Aguilera, Andrés

    2011-02-01

    Transcription of the switch (S) regions of immunoglobulin genes in B cells generates stable R-loops that are targeted by Activation Induced Cytidine Deaminase (AID), triggering class switch recombination (CSR), as well as translocations with c-MYC responsible for Burkitt's lymphomas. In Saccharomyces cerevisiae, stable R-loops are formed co-transcriptionally in mutants of THO, a conserved nuclear complex involved in mRNP biogenesis. Such R-loops trigger genome instability and facilitate deamination by human AID. To understand the mechanisms that generate genome instability mediated by mRNP biogenesis impairment and by AID, we devised a yeast chromosomal system based on different segments of mammalian S regions and c-MYC for the analysis of chromosomal rearrangements in both wild-type and THO mutants. We demonstrate that AID acts in yeast at heterologous S and c-MYC transcribed sequences leading to double-strand breaks (DSBs) which in turn cause chromosomal translocations via Non-Homologous End Joining (NHEJ). AID-induced translocations were strongly enhanced in yeast THO null mutants, consistent with the idea that AID-mediated DSBs depend on R-loop formation. Our study not only provides new clues to understand the role of mRNP biogenesis in preventing genome rearrangements and the mechanism of AID-mediated genome instability, but also shows that, once uracil residues are produced by AID-mediated deamination, these are processed into DSBs and chromosomal rearrangements by the general and conserved DNA repair functions present from yeast to human cells.

  5. AID induces double-strand breaks at immunoglobulin switch regions and c-MYC causing chromosomal translocations in yeast THO mutants.

    Directory of Open Access Journals (Sweden)

    José F Ruiz

    2011-02-01

    Full Text Available Transcription of the switch (S regions of immunoglobulin genes in B cells generates stable R-loops that are targeted by Activation Induced Cytidine Deaminase (AID, triggering class switch recombination (CSR, as well as translocations with c-MYC responsible for Burkitt's lymphomas. In Saccharomyces cerevisiae, stable R-loops are formed co-transcriptionally in mutants of THO, a conserved nuclear complex involved in mRNP biogenesis. Such R-loops trigger genome instability and facilitate deamination by human AID. To understand the mechanisms that generate genome instability mediated by mRNP biogenesis impairment and by AID, we devised a yeast chromosomal system based on different segments of mammalian S regions and c-MYC for the analysis of chromosomal rearrangements in both wild-type and THO mutants. We demonstrate that AID acts in yeast at heterologous S and c-MYC transcribed sequences leading to double-strand breaks (DSBs which in turn cause chromosomal translocations via Non-Homologous End Joining (NHEJ. AID-induced translocations were strongly enhanced in yeast THO null mutants, consistent with the idea that AID-mediated DSBs depend on R-loop formation. Our study not only provides new clues to understand the role of mRNP biogenesis in preventing genome rearrangements and the mechanism of AID-mediated genome instability, but also shows that, once uracil residues are produced by AID-mediated deamination, these are processed into DSBs and chromosomal rearrangements by the general and conserved DNA repair functions present from yeast to human cells.

  6. c-Myc quadruplex-forming sequence Pu-27 induces extensive damage in both telomeric and nontelomeric regions of DNA.

    Science.gov (United States)

    Islam, Md Ashraful; Thomas, Shelia D; Murty, Vundavalli V; Sedoris, Kara J; Miller, Donald M

    2014-03-21

    Quadruplex-forming DNA sequences are present throughout the eukaryotic genome, including in telomeric DNA. We have shown that the c-Myc promoter quadruplex-forming sequence Pu-27 selectively kills transformed cells (Sedoris, K. C., Thomas, S. D., Clarkson, C. R., Muench, D., Islam, A., Singh, R., and Miller, D. M. (2012) Genomic c-Myc quadruplex DNA selectively kills leukemia. Mol. Cancer Ther. 11, 66-76). In this study, we show that Pu-27 induces profound DNA damage, resulting in striking chromosomal abnormalities in the form of chromatid or chromosomal breaks, radial formation, and telomeric DNA loss, which induces γ-H2AX in U937 cells. Pu-27 down-regulates telomeric shelterin proteins, DNA damage response mediators (RAD17 and RAD50), double-stranded break repair molecule 53BP1, G2 checkpoint regulators (CHK1 and CHK2), and anti-apoptosis gene survivin. Interestingly, there are no changes of DNA repair molecules H2AX, BRCA1, and the telomere maintenance gene, hTERT. ΔB-U937, where U937 cells stably transfected with deleted basic domain of TRF2 is partially sensitive to Pu-27 but exhibits no changes in expression of shelterin proteins. However, there is an up-regulation of CHK1, CHK2, H2AX, BRCA1, and survivin. Telomere dysfunction-induced foci assay revealed co-association of TRF1with γ-H2AX in ATM deficient cells, which are differentially sensitive to Pu-27 than ATM proficient cells. Alt (alternating lengthening of telomere) cells are relatively resistant to Pu-27, but there are no significant changes of telomerase activity in both Alt and non-Alt cells. Lastly, we show that this Pu-27-mediated sensitivity is p53-independent. The data therefore support two conclusions. First, Pu-27 induces DNA damage within both telomeric and nontelomeric regions of the genome. Second, Pu-27-mediated telomeric damage is due, at least in part, to compromise of the telomeric shelterin protein complex.

  7. XRCC1、XPD、XRCC3、CCND1基因多态性与职业慢性苯中毒发病工龄的关联%Analysis for the association between genetic polymorphisms of XRCC1, XPD, XRCC3, CCND1 and the latency of the occupational chronic benzene poisoning

    Institute of Scientific and Technical Information of China (English)

    许建宁; 黄慧隆; 王全凯; 王雅文; 杨敏; 郑玉新

    2007-01-01

    目的 探讨DNA损伤修复基因XRCC1、XPD、XRCC3基因和细胞周期调控基因CCND1的多态性与慢性苯中毒发病工龄的关系.方法 以确诊的80名慢性苯中毒患者作为研究对象,应用PCR-RFLP分析技术,检测DNA损伤修复基因XRCC1(C26304T、G27466A、G28152A、G36189A位点)、XPD(C22541A、C23591T、A35931C位点)、XRCC3(C18067T位点)和细胞周期调控CCND1基因G870A位点的多态性,比较不同基因型Kaplan-Meier生存曲线,评价慢性苯中毒发病工龄与XRCC1、XPD、XRCC3和CCND1基因多态性的关联.结果 携带XRCC1 27466G/G基因型的个体发生慢性苯中毒的发病工龄比携带27466G/A+A/A变异基因型的个体长6.9年;携带CCND1870G/G基因型的个体比G/A+A/A基因型个体的发病工龄短6.2年.结论 XRCC1和CCND1基因多态性可能影响慢性职业性苯中毒的发病工龄.

  8. Effect of hydroxyapatite nanoparticles on the growth and p53/c-Myc protein expression of implanted hepatic VX2 tumor in rabbits by intravenous injection

    Institute of Scientific and Technical Information of China (English)

    Jun Hu; Zhi-Su Liu; Sheng-Li Tang; Yue-Ming He

    2007-01-01

    AIM:To evaluate the effect of hydroxyapatite nanoparticles (Nano HAP) by intravenous injection on the inhibition of implanted hepatic VX2 tumor growth in rabbits and cell p53/c-Myc protein expression.METHODS: 60 hepatic VX2 tumor-bearing rabbits was randomly divided into five groups. Nano HAP collosol 20 mg/kg, 40 mg/kg, 5-FU solutions 20 mg/mL, mixed liquor of 5-FU solution 20 mg/mL and Nano HAP collosol 20 mg/kg were infused by vein, normal saline conducted as the control. The general state, weight, liver function and gross tumor volume were detected dynamically.The expression of p53 and c-Myc gene protein in tumor tissue was detected by immunohistochemistry methods.RESULTS: The growth of implanted hepatic VX2 tumors was significantly inhibited in all therapy groups, 3 wk after the injection, the tumor control rates in Nano HAP collosol groups were 25.5% and 32.5% respectively,and the gross tumor volumes were obviously less than that of control group. (24.81 ± 5.17 and 22.73 ± 4.23vs 33.32 ± 5.26, P < 0.05). The tumor control rate of 5-FU group was 43.7% (18.74 ± 4.40 vs 33.32 ± 5.26,P < 0.05), but the general state of the animals after injection aggravated; and the adverse reaction in the drug combination group obviously decreased. Due to the effect of Nano HAP, the positive expression of tumor associated the mutated p53 and c-Myc in tumor tissue was decreased obviously compared with the control group.CONCLUSION: Nano HAP has evident inhibitory action on rabbit implanted hepatic VX2 tumor in vivo, which may be the result of decreasing the expression of the mutated p53 and c-myc, and drug combination can obviously decrease the adverse reaction of 5-FU.

  9. In vivo inhibition of c-MYC in myeloid cells impairs tumor-associated macrophage maturation and pro-tumoral activities.

    Directory of Open Access Journals (Sweden)

    Oscar M Pello

    Full Text Available Although tumor-associated macrophages (TAMs are involved in tumor growth and metastasis, the mechanisms controlling their pro-tumoral activities remain largely unknown. The transcription factor c-MYC has been recently shown to regulate in vitro human macrophage polarization and be expressed in macrophages infiltrating human tumors. In this study, we exploited the predominant expression of LysM in myeloid cells to generate c-Myc(fl/fl LysM(cre/+ mice, which lack c-Myc in macrophages, to investigate the role of macrophage c-MYC expression in cancer. Under steady-state conditions, immune system parameters in c-Myc(fl/fl LysM(cre/+ mice appeared normal, including the abundance of different subsets of bone marrow hematopoietic stem cells, precursors and circulating cells, macrophage density, and immune organ structure. In a model of melanoma, however, TAMs lacking c-Myc displayed a delay in maturation and showed an attenuation of pro-tumoral functions (e.g., reduced expression of VEGF, MMP9, and HIF1α that was associated with impaired tissue remodeling and angiogenesis and limited tumor growth in c-Myc(fl/fl LysM(cre/+ mice. Macrophage c-Myc deletion also diminished fibrosarcoma growth. These data identify c-Myc as a positive regulator of the pro-tumoral program of TAMs and suggest c-Myc inactivation as an attractive target for anti-cancer therapy.

  10. CD8+ T cells promote proliferation of benign prostatic hyperplasia epithelial cells under low androgen level via modulation of CCL5/STAT5/CCND1 signaling pathway

    Science.gov (United States)

    Yang, Yang; Hu, Shuai; Liu, Jie; Cui, Yun; Fan, Yu; Lv, Tianjing; Liu, Libo; Li, Jun; He, Qun; Han, Wenke; Yu, Wei; Sun, Yin; Jin, Jie

    2017-01-01

    Previous studies by our group have shown that low intra-prostatic dihydrotestosterone (DHT) induced BPH epithelial cells (BECs) to recruit CD8+ T cells. However, the influence of the recruited CD8+ T cells on BECs under a low androgen level is still unknown. Here, we found CD8+ T cells have the capacity to promote proliferation of BECs in low androgen condition. Mechanism dissection revealed that interaction between CD8+ T cells and BECs through secretion of CCL5 might promote the phosphorylation of STAT5 and a higher expression of CCND1 in BECs. Suppressed CCL5/STAT5 signals via CCL5 neutralizing antibody or STAT5 inhibitor Pimozide led to reverse CD8+ T cell-enhanced BECs proliferation. IHC analysis from Finasteride treated patients showed PCNA expression in BECs was highly correlated to the level of CD8+ T cell infiltration and the expression of CCL5. Consequently, our data indicated infiltrating CD8+ T cells could promote the proliferation of BECs in low androgen condition via modulation of CCL5/STAT5/CCND1 signaling. The increased secretion of CCL5 from the CD8+ T cells/BECs interaction might help BECs survive in a low DHT environment. Targeting these signals may provide a new potential therapeutic approach to better treat BPH patients who failed the therapy of 5α-reductase inhibitors. PMID:28216616

  11. miR-2861 acts as a tumor suppressor via targeting EGFR/AKT2/CCND1 pathway in cervical cancer induced by human papillomavirus virus 16 E6.

    Science.gov (United States)

    Xu, Junfen; Wan, Xiaoyun; Chen, Xiaojing; Fang, Yifeng; Cheng, Xiaodong; Xie, Xing; Lu, Weiguo

    2016-07-01

    Persistent infection with oncogenic human papillomavirus viruses (HPVs) is a casual factor for cervical cancer and its precursors, and the abnormal constitutive expression of viral oncoprotein E6 is a key event during the malignant transformation. Here, we performed miRNA microarray to identify changes of miRNAs following ectopic HPV16 E6 overexpression in HEK293T cells and found miR-2861 was greatly decreased in both HEK293T and HaCaT cells expressing HPV16 E6 compared to vector control. Further, we demonstrated a biological link among HPV16 E6, miR-2861, EGFR, AKT2, and CCND1 in cervical cancer cells. We showed that miR-2861 was downregulated in cervical cancer tissues and negatively correlated with advanced tumor stage and lymph node metastasis. Overexpression of miR-2861 suppressed cervical cancer cell proliferation and invasion and enhanced apoptosis. Subsequent investigation revealed that EGFR, AKT2, and CCND1 were all the direct targets of miR-2861. Importantly, silencing EGFR, AKT2, and/or CCND1 recapitulated the cellular effects seen upon miR-2861 overexpression. Restoration of EGFR, AKT2, and/or CCND1 counteracted the effects of miR-2861 expression. Thus, we identified a new pathway employing miR-2861, EGFR, AKT2, and CCND1 that may mediate HPV16 E6 induced initiation and progression of cervical cancer.

  12. Nuclear localization of vascular endothelial growth factor-D and regulation of c-Myc-dependent transcripts in human lung fibroblasts.

    Science.gov (United States)

    El-Chemaly, Souheil; Pacheco-Rodriguez, Gustavo; Malide, Daniela; Meza-Carmen, Victor; Kato, Jiro; Cui, Ye; Padilla, Philip I; Samidurai, Arun; Gochuico, Bernadette R; Moss, Joel

    2014-07-01

    Lymphangiogenesis and angiogenesis are processes that are, in part, regulated by vascular endothelial growth factor (VEGF)-D. The formation of lymphatic structures has been implicated in multiple lung diseases, including pulmonary fibrosis. VEGF-D is a secreted protein produced by fibroblasts and macrophages, which induces lymphangiogenesis by signaling via VEGF receptor-3, and angiogenesis through VEGF receptor-2. VEGF-D contains a central VEGF homology domain, which is the biologically active domain, with flanking N- and C-terminal propeptides. Full-length VEGF-D (∼ 50 kD) is proteolytically processed in the extracellular space, to generate VEGF homology domain that contains the VEGF-D receptor-binding sites. Here, we report that, independent of its cell surface receptors, full-length VEGF-D accumulated in nuclei of fibroblasts, and that this process appears to increase with cell density. In nuclei, full-length VEGF-D associated with RNA polymerase II and c-Myc. In cells depleted of VEGF-D, the transcriptionally regulated genes appear to be modulated by c-Myc. These findings have potential clinical implications, as VEGF-D was found in fibroblast nuclei in idiopathic pulmonary fibrosis, a disease characterized by fibroblast proliferation. These findings are consistent with actions of full-length VEGF-D in cellular homeostasis in health and disease, independent of its receptors.

  13. Abnormal expression of c-Myc in human bronchial epithelial cells malignantly transformed by anti-BPDE

    Institute of Scientific and Technical Information of China (English)

    Juan FU; Yiguo JIANG; Xuemin CHEN

    2008-01-01

    Anti-benzo[a]pyrene-7,8-diol-9,10-epoxide (anti-BPDE) is a metabolite of benzo[a]pyrene (B[a] P) and acts as a potent mutagen in mammalian systems. However, molecular mechanisms related to anti-BPDE-induced carcinogenesis are poorly understood. Here, we investigated the expression of proto-oncogene c-myc in human bronchial epithelial cells (16H BE-T) transformed by exposure to anti-BPDE. The levels ofmRNA and pro-tein of c-M yc were examined in the 16HBE-T and vehicle-treated control cells (16HBE-N) by using different meth-ods respectively, including reverse transcriptase-polymer-ase chain reaction (RT-PCR), quantitative real-time PCR (Q-PCR), western blot and immunocytochemical meth-ods. The level of c-myc mRNA appeared to be signifi-cantly increased in 16HBE-T, as compared with those of the 16H BE-N. Likewise, the expression of c-Myc protein was significantly enhanced as compared with those of the control cells. Moreover, the localization of c-Myc protein shows mainly nuclear staining in 16HBE-T. In conclu-sion, the abnormal expression of c-Myc was present in anti-BPDE malignantly transformed 16HBE cells, which may be involved in the carcinogenesis molecular mech-anism of anti-BPDE.

  14. C-Myc regulation by costimulatory signals modulates the generation of CD8+ memory T cells during viral infection.

    Science.gov (United States)

    Haque, Mohammad; Song, Jianyong; Fino, Kristin; Wang, Youfei; Sandhu, Praneet; Song, Xinmeng; Norbury, Christopher; Ni, Bing; Fang, Deyu; Salek-Ardakani, Shahram; Song, Jianxun

    2016-01-01

    The signalling mechanisms of costimulation in the development of memory T cells remain to be clarified. Here, we show that the transcription factor c-Myc in CD8(+) T cells is controlled by costimulatory molecules, which modulates the development of memory CD8(+) T cells. C-Myc expression was dramatically reduced in Cd28(-/-) or Ox40(-/-) memory CD8(+) T cells, and c-Myc over-expression substantially reversed the defects in the development of T-cell memory following viral infection. C-Myc regulated the expression of survivin, an inhibitor of apoptosis, which promoted the generation of virus-specific memory CD8(+) T cells. Moreover, over-expression of survivin with bcl-xL, a downstream molecule of NF-κB and intracellular target of costimulation that controls survival, in Cd28(-/-) or Ox40(-/-) CD8(+) T cells, reversed the defects in the generation of memory T cells in response to viral infection. These results identify c-Myc as a key controller of memory CD8(+) T cells from costimulatory signals.

  15. Modulation of Cellular Migration and Survival by c-Myc through the Downregulation of Urokinase (uPA) and uPA Receptor▿ †

    Science.gov (United States)

    Alfano, Daniela; Votta, Giuseppina; Schulze, Almut; Downward, Julian; Caputi, Mario; Stoppelli, Maria Patrizia; Iaccarino, Ingram

    2010-01-01

    It has been proposed that c-Myc proapoptotic activity accounts for most of its restraint of tumor formation. We established a telomerase-immortalized human epithelial cell line expressing an activatable c-Myc protein. We found that c-Myc activation induces, in addition to increased sensitivity to apoptosis, reductions in cell motility and invasiveness. Transcriptome analysis revealed that urokinase (uPA) and uPA receptor (uPAR) were strongly downregulated by c-Myc. Evidence is provided that the repression of uPA and uPAR may account for most of the antimigratory and proapoptotic activities of c-Myc. c-Myc is known to cooperate with Ras in cellular transformation. We therefore investigated if this cooperation could converge in the control of uPA/uPAR expression. We found that Ras is able to block the effects of c-Myc activation on apoptosis and cellular motility but not on cell invasiveness. Accordingly, the activation of c-Myc in the context of Ras expression had only minor influence on uPAR expression but still had a profound repressive effect on uPA expression. Thus, the differential regulation of uPA and uPAR by c-Myc and Ras correlates with the effects of these two oncoproteins on cell motility, invasiveness, and survival. In conclusion, we have discovered a novel link between c-Myc and uPA/uPAR. We propose that reductions of cell motility and invasiveness could contribute to the inhibition of tumorigenesis by c-Myc and that the regulation of uPA and uPAR expression may be a component of the ability of c-Myc to reduce motility and invasiveness. PMID:20123981

  16. Modulation of cellular migration and survival by c-Myc through the downregulation of urokinase (uPA) and uPA receptor.

    Science.gov (United States)

    Alfano, Daniela; Votta, Giuseppina; Schulze, Almut; Downward, Julian; Caputi, Mario; Stoppelli, Maria Patrizia; Iaccarino, Ingram

    2010-04-01

    It has been proposed that c-Myc proapoptotic activity accounts for most of its restraint of tumor formation. We established a telomerase-immortalized human epithelial cell line expressing an activatable c-Myc protein. We found that c-Myc activation induces, in addition to increased sensitivity to apoptosis, reductions in cell motility and invasiveness. Transcriptome analysis revealed that urokinase (uPA) and uPA receptor (uPAR) were strongly downregulated by c-Myc. Evidence is provided that the repression of uPA and uPAR may account for most of the antimigratory and proapoptotic activities of c-Myc. c-Myc is known to cooperate with Ras in cellular transformation. We therefore investigated if this cooperation could converge in the control of uPA/uPAR expression. We found that Ras is able to block the effects of c-Myc activation on apoptosis and cellular motility but not on cell invasiveness. Accordingly, the activation of c-Myc in the context of Ras expression had only minor influence on uPAR expression but still had a profound repressive effect on uPA expression. Thus, the differential regulation of uPA and uPAR by c-Myc and Ras correlates with the effects of these two oncoproteins on cell motility, invasiveness, and survival. In conclusion, we have discovered a novel link between c-Myc and uPA/uPAR. We propose that reductions of cell motility and invasiveness could contribute to the inhibition of tumorigenesis by c-Myc and that the regulation of uPA and uPAR expression may be a component of the ability of c-Myc to reduce motility and invasiveness.

  17. 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.

  18. Targeting angiogenesis via a c-Myc/hypoxia-inducible factor-1alpha-dependent pathway in multiple myeloma.

    Science.gov (United States)

    Zhang, Jing; Sattler, Martin; Tonon, Giovanni; Grabher, Clemens; Lababidi, Samir; Zimmerhackl, Alexander; Raab, Marc S; Vallet, Sonia; Zhou, Yiming; Cartron, Marie-Astrid; Hideshima, Teru; Tai, Yu-Tzu; Chauhan, Dharminder; Anderson, Kenneth C; Podar, Klaus

    2009-06-15

    Bone marrow angiogenesis is associated with multiple myeloma (MM) progression. Here, we report high constitutive hypoxia-inducible factor-1alpha (Hif-1alpha) expression in MM cells, which is associated with oncogenic c-Myc. A drug screen for anti-MM agents that decrease Hif-1alpha and c-Myc levels identified a variety of compounds, including bortezomib, lenalidomide, enzastaurin, and adaphostin. Functionally, based on transient knockdowns and overexpression, our data delineate a c-Myc/Hif-1alpha-dependent pathway mediating vascular endothelial growth factor production and secretion. The antiangiogenic activity of our tool compound, adaphostin, was subsequently shown in a zebrafish model and translated into a preclinical in vitro and in vivo model of MM in the bone marrow milieu. Our data, therefore, identify Hif-1alpha as a novel molecular target in MM and add another facet to anti-MM drug activity.

  19. Alterations of C-MYC, NKX3.1, and E-cadherin expression in canine prostate carcinogenesis

    DEFF Research Database (Denmark)

    Fonseca-Alves, Carlos E; Rodrigues, Marcela M P; de Moura, Veridiana M B D;

    2013-01-01

    therapies. In humans, the PCa frequently exhibits mutations in the C-MYC and a reduced expression of the E-cadherin and NKX3.1 proteins. This study's objective was to evaluate the NKX3.1, C-MYC, and E-cadherin expression in the canine normal prostate, benign prostatic hyperplasia (BPH), proliferative......The dog (canis lupus familiaris) is the only other species besides humans that develop spontaneous prostatic carcinomas (PCa) at a high frequency. The canine model is primarily utilized for the study of the PCa molecular mechanisms and provides a natural animal model for the study of potential...... inflammatory atrophy (PIA) and PCa and to verify differences in expression and subcellular localization of these proteins in the prostatic carcinogenesis. A tissue microarray (TMA) slide was constructed, and immunohistochemistry with antibodies raised against C-MYC, NKX3.1, E-cadherin and p63 was performed...

  20. Elevation of c-MYC disrupts HLA class II-mediated immune recognition of human B cell tumors.

    Science.gov (United States)

    God, Jason M; Cameron, Christine; Figueroa, Janette; Amria, Shereen; Hossain, Azim; Kempkes, Bettina; Bornkamm, Georg W; Stuart, Robert K; Blum, Janice S; Haque, Azizul

    2015-02-15

    Elevated levels of the transcription factor c-myc are strongly associated with various cancers, and in particular B cell lymphomas. Although many of c-MYC's functions have been elucidated, its effect on the presentation of Ag through the HLA class II pathway has not been reported previously. This is an issue of considerable importance, given the low immunogenicity of many c-MYC-positive tumors. We report in this paper that increased c-MYC expression has a negative effect on the ability of B cell lymphomas to functionally present Ags/peptides to CD4(+) T cells. This defect was associated with alterations in the expression of distinct cofactors as well as interactions of antigenic peptides with class II molecules required for the presentation of class II-peptide complexes and T cell engagement. Using early passage Burkitt's lymphoma (BL) tumors and transformed cells, we show that compared with B lymphoblasts, BL cells express decreased levels of the class II editor HLA-DM, lysosomal thiol-reductase GILT, and a 47-kDa enolase-like protein. Functional Ag presentation was partially restored in BL cells treated with a c-MYC inhibitor, demonstrating the impact of this oncogene on Ag recognition. This restoration of HLA class II-mediated Ag presentation in early passage BL tumors/cells was linked to enhanced HLA-DM expression and a concurrent decrease in HLA-DO in BL cells. Taken together, these results reveal c-MYC exerts suppressive effects at several critical checkpoints in Ag presentation, which contribute to the immunoevasive properties of BL tumors.

  1. 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.

  2. 原癌基因c-myc真核表达载体构建及其生物学作用%Construction and identification of an original oncogene c-myc eukaryotic expression vector

    Institute of Scientific and Technical Information of China (English)

    荆志波; 韦丹丹; 逄越

    2013-01-01

    目的 利用基因工程技术构建携带原癌基因c-myc的真核表达载体pIRES2-AcGFPl-Nuc-c-myc重组质粒并在Hela细胞中表达.方法 以构建好的表达质粒pET28a-c-myc为基础,利用PCR方法扩增c-myc基因,并加入EcoR Ⅰ和SmaⅠ酶切位点,克隆至pMD 19-T Simple载体,双酶切后将其与同样经过双酶切的真核表达载体pIRES2-AcGFP1-Nuc连接,通过PCR、酶切及测序鉴定重组质粒的正确性,再将重组质粒pIRES2-AcGFPl-Nuc-c-myc转染Hela细胞,利用荧光显微镜观察GFP表达,利用MTT和免疫印迹证实c-myc蛋白表达量提高.结果 经PCR和酶切鉴定与预期结果相符,测序结果与GenBank中报道的序列完全一致,成功构建了重组表达质粒.免疫印迹证实c-myc基因在Hela细胞中得到表达.MTT结果显示Hela细胞数量显著增加.结论 真核表达载体pIRES2-AcGFP 1-Nuc-c-myc成功构建,c-myc基因在Hela细胞中成功表达,具有生物学活性.%This study designed to construct and express original oncogene c-myc eukaryotic expression vector pIRES2-AcGFP1-Nuc-c-myc using gene engineering technique.The c-myc gene was obtained by PCR amplification from pET28a-c-myc,to constructed pIRES2-AcGFPl-Nuc eukaryotic expression vector,which was then confirmed by PCR method,restriction analysis and DNA sequencing.In addition,the recombinant plasmid pIRES2-AcGFPl-Nuc-c-myc was transfected to Hela cells,and green fluorescent protein was expressed successfully under fluorescence microscopy.Analysis of Western blotting showed that c-myc protein expression was increased in Hela cell,and MTT assay indicated c-myc protein could promote the proliferation of Hela cells.In conclusion,eukaryotic expression vector of c-myc gene was constructed and transfected,which lay foundation for the lamprey cell line research.

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

    Directory of Open Access Journals (Sweden)

    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

  4. Progestin and antiprogestin responsiveness in breast cancer is driven by the PRA/PRB ratio via AIB1 or SMRT recruitment to the CCND1 and MYC promoters.

    Science.gov (United States)

    Wargon, Victoria; Riggio, Marina; Giulianelli, Sebastián; Sequeira, Gonzalo R; Rojas, Paola; May, María; Polo, María L; Gorostiaga, María A; Jacobsen, Britta; Molinolo, Alfredo; Novaro, Virginia; Lanari, Claudia

    2015-06-01

    There is emerging interest in understanding the role of progesterone receptors (PRs) in breast cancer. The aim of this study was to investigate the proliferative effect of progestins and antiprogestins depending on the relative expression of the A (PRA) and B (PRB) isoforms of PR. In mifepristone (MFP)-resistant murine carcinomas antiprogestin responsiveness was restored by re-expressing PRA using demethylating agents and histone deacetylase inhibitors. Consistently, in two human breast cancer xenograft models, one manipulated to overexpress PRA or PRB (IBH-6 cells), and the other expressing only PRA (T47D-YA) or PRB (T47D-YB), MFP selectively inhibited the growth of PRA-overexpressing tumors and stimulated IBH-6-PRB xenograft growth. Furthermore, in cells with high or equimolar PRA/PRB ratios, which are stimulated to proliferate in vitro by progestins, and are inhibited by MFP, MPA increased the interaction between PR and the coactivator AIB1, and MFP favored the interaction between PR and the corepressor SMRT. In a PRB-dominant context in which MFP stimulates and MPA inhibits cell proliferation, the opposite interactions were observed. Chromatin immunoprecipitation assays in T47D cells in the presence of MPA or MFP confirmed the interactions between PR and the coregulators at the CCND1 and MYC promoters. SMRT downregulation by siRNA abolished the inhibitory effect of MFP on MYC expression and cell proliferation. Our results indicate that antiprogestins are therapeutic tools that selectively inhibit PRA-overexpressing tumors by increasing the SMRT/AIB1 balance at the CCND1 and MYC promoters.

  5. c-myc mRNA in cytoskeletal-bound polysomes in fibroblasts.

    Science.gov (United States)

    Hesketh, J E; Campbell, G P; Whitelaw, P F

    1991-03-01

    3T3 fibroblasts were treated sequentially with 25 mM-KCl/0.05% Nonidet P40, 130 mM-KCl/0.05% Nonidet P40 and finally with 1% Nonidet P40/1% deoxycholate in order to release free, cytoskeletal-bound and membrane-bound polysomes respectively. The membrane-bound fraction was enriched in the mRNA for the membrane protein beta 2-microglobulin, whereas the cytoskeletal-bound polysomes were enriched in c-myc mRNA. Actin mRNA was present in both free and cytoskeletal-bound polysomes. The results suggest that cytoskeletal-bound polysomes are involved in the translation of specific mRNA species.

  6. 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.

  7. Combined loss of PUMA and p21 accelerates c-MYC-driven lymphoma development considerably less than loss of one allele of p53.

    Science.gov (United States)

    Valente, L J; Grabow, S; Vandenberg, C J; Strasser, A; Janic, A

    2016-07-21

    The tumor suppressor p53 is mutated in ~50% of human cancers. P53 is activated by a range of stimuli and regulates several cellular processes, including apoptotic cell death, cell cycle arrest, senescence and DNA repair. P53 induces apoptosis via transcriptional induction of the BH3-only proteins PUMA (p53-upregulated modulator of apoptosis) and NOXA, and cell cycle arrest via p21. Induction of these processes was proposed to be critical for p53-mediated tumor suppression. It is therefore surprising that mice lacking PUMA, NOXA and p21, as well as mice bearing mutations in p53 that impair the transcriptional activation of these genes, are not tumor prone, unlike mice lacking p53 function, which spontaneously develop tumors with 100% incidence. These p53 target genes and the processes they regulate may, however, impact differently on tumor development depending on the oncogenic drivers. For example, loss of PUMA enhances c-MYC-driven lymphoma development in mice, but, interestingly, the acceleration was less impressive compared with that caused by the loss of even a single p53 allele. Different studies have reported that loss of p21 can accelerate, delay or have no impact on tumorigenesis. In an attempt to resolve this controversy, we examined whether loss of p21-mediated cell cycle arrest cooperates with PUMA deficiency in accelerating lymphoma development in Eμ-Myc mice (overexpressing c-MYC in B-lymphoid cells). We found that Eμ-Myc mice lacking both p21 and PUMA (Eμ-Myc;Puma(-/-);p21(-/-)) developed lymphoma at a rate comparable to Eμ-Myc;Puma(-/-) animals, notably with considerably longer latency than Eμ-Myc;p53(+/-)mice. Loss of p21 had no impact on the numbers, cycling or survival of pre-leukemic Eμ-Myc B-lymphoid cells, even when PUMA was lost concomitantly. These results demonstrate that even in the context of deregulated c-MYC expression, p53 must suppress tumor development by activating processes apart from, or in addition to, PUMA

  8. Telomerase in relation to expression of p53, c-Myc and estrogen receptor in ovarian tumours

    NARCIS (Netherlands)

    Wisman, GBA; Hollema, H; Helder, MN; Knol, AJ; Van Der Meer, GT; Krans, M; De Jong, S; De Vries, EGE; Van Der Zee, AGJ

    2003-01-01

    Telomerase activity and its subunits (hTERC, hTERT mRNA) were evaluated in ovarian tumours in relation to the expression of p53, c-Myc and estrogen receptor (ER). Furthermore, relations between telomerase activity, hTERC and hTERT with known clinicopathologic prognostic factors and survival in patie

  9. Induction of endogenous telomerase (hTERT) by c-Myc in WI-38 fibroblasts transformed with specific genetic elements.

    Science.gov (United States)

    Casillas, Mark A; Brotherton, Scott L; Andrews, Lucy G; Ruppert, J Michael; Tollefsbol, Trygve O

    2003-10-16

    Elucidation of the mechanisms governing expression of the human telomerase reverse transcriptase (hTERT) is important for understanding cancer pathogenesis. Approximately 90% of tumors express hTERT, the major catalytic component of telomerase. Activation of telomerase is an early event, and high levels of this activity correlate with poor prognosis. Recent studies have shown that the transcription factors c-Myc and Mad1 activate and repress hTERT, respectively. It is not clear how these transcription factors compete for the same recognition sequence in the hTERT core promoter region. Studies have shown that the combined expression of SV40 large T antigen (T-Ag), hTERT, and H-Ras is able to transform human cells. In this study, we used a distinct human cell type, WI-38 fetal lung fibroblasts used extensively for senescence studies. We transduced cells with amphotropic retroviral constructs containing SV40 T antigen, hTERT, and activated H-ras. Transduced cells exhibited anchorage independence in soft agar and expressed increased levels of c-Myc and endogenous hTERT. These effects were observed by 25 population doublings (PDs) following the establishment of the neoplastic cell line. During the process of transformation, we observed a switch from Mad1/Max to c-Myc/Max binding to oligonucleotide sequences containing the hTERT promoter distal and proximal E-boxes. c-Myc can bind specifically to the hTERT promoter in vitro, indicating that c-Myc expression in tumors may account for the increased expression of hTERT observed in vivo. These findings indicate that the widely used model system of WI-38 fibroblasts can be employed for transformation studies using defined genetic elements and that the endogenous hTERT and c-Myc are induced in these cells during early tumorigenesis. Such studies should have important implications in the mechanisms of hTERT and c-Myc induction in the beginning stages of tumorigenesis and facilitate extension of these studies to novel models of

  10. C-MYC and BCL2 translocation frequency in diffuse large B-cell lymphomas: A study of 97 patients

    Directory of Open Access Journals (Sweden)

    Bahar Akkaya

    2016-01-01

    Full Text Available Purpose: Diffuse large B-cell lymphoma (DLBCL is an aggressive non-Hodgkin lymphoma with marked biologic heterogeneity. MYC and BCL2 rearrangements have been reported in a proportion of DLBCLs, where they may be associated with an adverse clinical outcome. The aim of this study was to determine the frequency of MYC and BCL2 translocations in DLBCL and assess the prognostic impact in DLBCL patients. Materials and Methods:   In the present study, we evaluated the expression patterns of CD 10, BCL6, and MUM 1 by immunohistochemistry in 121 cases with DLBCL in tissue microarray (TMA: 62 cases in germinal center B-cells (GCBs; and 59 cases in activated B-cells (ABCs of which 60 were females and 61 were males. MYC and BCL2 rearrangements were investigated by interphase fluorescence in situ hybridization on TMAs in 97 DLBCLs. Result: MYC rearrangements were observed in 11 of 97 cases. There was no association with other clinical features, including age, sex, and nodal/extranodal disease. MYC rearrangement was associated with significantly worse overall survival (P < 0.01. BCL2 rearrangements were observed in 14 of 97 cases. There was no association with other clinical features including age and sex. BCL2 rearrangement had a worse outcome (P < 0.01. MYC and BCL2 rearrangements were observed in 3 of 97 cases with the age of  53 (female, 53, 63 years old, respectively, died in 24, 18, and 35 months after the diagnosis. Two cases had primary nodal and one case primary extranodal presentations. All these patients had stage IV disease. Conclusion: We concluded that C-MYC and BCL2 may contribute to aggressive transformation, and more mechanism-based therapy should be explored. Targeted therapies involving these rearrangements and its associated pathways may change the fate of DLBCLs. Analysis of MYC gene rearrangement along with BCL2 is critical in the identification of high-risk patients with poor prognosis.

  11. Elevation of c-MYC Disrupts HLA Class II-mediated Immune Recognition of Human B-cell Tumors1

    Science.gov (United States)

    God, Jason M.; Cameron, Christine; Figueroa, Janette; Amria, Shereen; Hossain, Azim; Kempkes, Bettina; Bornkamm, Georg W.; Stuart, Robert K.; Blum, Janice S.; Haque, Azizul

    2014-01-01

    Elevated levels of the transcription factor c-myc are strongly associated with various cancers, and in particular B-cell lymphomas. While many of c-MYC’s functions have been elucidated, its effect on the presentation of antigen (Ag) through the HLA class II pathway has not previously been reported. This is an issue of considerable importance, given the low immunogenicity of many c-MYC-positive tumors. We report here that increased c-MYC expression has a negative effect on the ability of B-cell lymphomas to functionally present Ags/peptides to CD4+ T cells. This defect was associated with alterations in the expression of distinct co-factors as well as interactions of antigenic peptides with class II molecules required for the presentation of class II-peptide complexes and T cell engagement. Using early passage Burkitt’s lymphoma (BL) tumors and transformed cells, we show that compared to B-lymphoblasts, BL cells express decreased levels of the class II editor HLA-DM, lysosomal thiol-reductase GILT, and a 47kDa enolase-like protein. Functional Ag presentation was partially restored in BL cells treated with a c-MYC inhibitor, demonstrating the impact of this oncogene on Ag recognition. This restoration of HLA class II-mediated Ag presentation in early passage BL tumors/cells was linked to enhanced HLA-DM expression and a concurrent decrease in HLA-DO in BL cells. Taken together, these results reveal c-MYC exerts suppressive effects at several critical checkpoints in Ag presentation which contribute to the immunoevasive properties of BL tumors. PMID:25595783

  12. 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.

  13. Clinical significance of high c-MYC and low MYCBP2 expression and their association with Ikaros dysfunction in adult acute lymphoblastic leukemia.

    Science.gov (United States)

    Ge, Zheng; Guo, Xing; Li, Jianyong; Hartman, Melanie; Kawasawa, Yuka Imamura; Dovat, Sinisa; Song, Chunhua

    2015-12-01

    Increased expression of c-MYC is observed in both Acute Myeloid Leukemia (AML) and T-cell Acute Lymphoblastic Leukemia (T-ALL). MYC binding protein 2 (MYCBP2) is a probable E3 ubiquitin ligase and its function in leukemia is unknown. IKZF1 deletion is associated with the development and poor outcome of ALL. Here, we observed significant high c-MYC expression and low MYCBP2 expression in adult ALL patients. Patients with high c-MYC expression and/or low MYCBP2 expression had higher WBC counts and a higher percentage of CD34+ or CD33+ cells, as well as splenomegaly, liver infiltration, higher BM blasts, and lower CR rate. Ikaros bound to the regulatory regions of c-MYC and MYCBP2, suppressed c-MYC and increased MYCBP2 expression in ALL cells. Expression of c-MYC mRNA was significantly higher in patients with IKZF1 deletion; conversely MYCBP2 mRNA expression was significantly lower in those patients. A CK2 inhibitor, which acts as an Ikaros activator, also suppressed c-MYC and increased MYCBP2 expression in an Ikaros (IKZF1) dependent manner in the ALL cells. In summary, our data indicated the correlation of high c-MYC expression, low MYCBP2 expression and high c-MYC plus low MYCBP2 expression with high-risk factors and proliferation markers in adult ALL patients. Our data also revealed an oncogenic role for an Ikaros/MYCBP2/c-MYC axis in adult ALL, providing a mechanism of target therapies that activate Ikaros in adult ALL.

  14. A novel role for c-Myc in G protein-coupled receptor kinase 4 (GRK4) transcriptional regulation in human kidney proximal tubule cells.

    Science.gov (United States)

    Gildea, John J; Tran, Hanh T; Van Sciver, Robert E; Bigler Wang, Dora; Carlson, Julia M; Felder, Robin A

    2013-05-01

    The G protein-coupled receptor kinase 4 (GRK4) negatively regulates the dopaminergic system by desensitizing the dopamine-1-receptor. The expressional control of GRK4 has not been reported, but here we show that the transcription factor c-Myc binds to the promoter of GRK4 and positively regulates GRK4 protein expression in human renal proximal tubule cells (RPTCs). Addition of phorbol esters to RPTCs not only increased c-Myc binding to the GRK4 promoter but also increased both phospho-c-Myc and GRK4 expression. The phorbol ester-mediated increase in GRK4 expression was completely blocked by the c-Myc inhibitor, 10074-G5, indicating that GRK4 is downstream of phospho-c-Myc. The autocrine production of angiotensin II (Ang II) in RPTCs increased the phosphorylation and activation of c-Myc and subsequently GRK4 expression. 3-Amino-4-thio-butyl sulfonate, an inhibitor of aminopeptidase A, increased RPTC secretion of Ang II. 3-Amino-4-thio-butyl sulfonate or Ang II increased the expression of both phospho-c-Myc and GRK4, which was blocked by 10074-G5. Blockade of the Ang II type 1 receptor with losartan decreased phospho-c-Myc and GRK4 expression. Both inhibition of c-Myc activity and blockade of Ang II type 1 receptor restored the coupling of dopamine-1-receptor to adenylyl cyclase stimulation in uncoupled RPTCs, whereas phorbol esters or Ang II caused the uncoupling of normally coupled RPTCs. We suggest that the Ang II type 1 receptor impairs dopamine-1-receptor function via c-Myc activation of GRK4. This novel pathway may be involved in the increase in blood pressure in hypertension that is mediated by increased activity of the renin-angiotensin system and decreased activity of the renal dopaminergic system.

  15. Expressions of Pokemon and c-myc in colorectal cancer and their clinical significance%Pokemon和c-myc在结直肠癌中的表达及临床意义

    Institute of Scientific and Technical Information of China (English)

    郭柏华; 杨章林; 董国钢; 王笑凌; 班雨

    2015-01-01

    目的 检测Pokemon和c-myc在结直肠癌、结直肠腺瘤和正常结直肠黏膜组织中的表达情况,研究结直肠癌组织中Pokemon和c-myc的表达与临床病理因素的关系.方法 收集86例结直肠癌患者肿瘤组织标本,60例结直肠腺瘤组织标本和40例正常结直肠黏膜组织标本.采用免疫组织化学法检测组织中Pokemon和c-myc蛋白表达情况,反转录聚合酶链反应检测组织中Pokemon和c-myc基因表达水平,并分析其与结直肠癌临床病理因素的关系.结果 结直肠癌组织中Pokemon和c-myc蛋白阳性表达率均明显高于结直肠腺瘤组织和正常结直肠黏膜组织[69.8%(60/86)比13.3%(8/60)和5.0%(2/40)、73.3%(63/86)比15.0%(9/60)和2.5%(1/40)],结直肠癌组织中Pokemon和c-myc基因表达水平均明显高于结直肠腺瘤组织和正常结直肠黏膜组织(0.915±0.247比0.358±0.102和0.277±0.085、1.272±0.360比0.398±0.153和0.255 ± 0.097),差异有统计学意义(P<0.05).结直肠癌组织中Pokemon和c-myc基因的表达水平与肿瘤浸润程度、肿瘤分化程度、淋巴结转移、远处转移和Dukes分期有关,差异有统计学意义(P<0.05),但与性别、年龄和肿瘤直径无关(P>0.05).结论 Pokemon和c-myc在结直肠癌组织中高表达,且这种表达与结直肠癌临床病理特征有关,提示Pokemon和c-myc可作为结直肠癌患者临床治疗的评估指标.%Objective To investigate the expressions of Pokemon and c-myc in colorectal cancer,colorectal adenomas and normal colorectal mucosa tissues,and demonstrate its relationship with clinicopathological features and prognosis in patients with colorectal cancer.Methods The specimens were taken from colorectal cancer tissue of 86 patients,colorectal adenomas tissue of 60 patients,and 40 normal colorectal mucosa tissue.The expressions of Pokemon and c-myc protein were detected by immunohistochemistry,and the expressions of Pokemon and c-myc gene were detected by reverse

  16. c-Myc Alters Substrate Utilization and O-GlcNAc Protein Posttranslational Modifications without Altering Cardiac Function during Early Aortic Constriction.

    Directory of Open Access Journals (Sweden)

    Dolena Ledee

    Full Text Available Hypertrophic stimuli cause transcription of the proto-oncogene c-Myc (Myc. Prior work showed that myocardial knockout of c-Myc (Myc attenuated hypertrophy and decreased expression of metabolic genes after aortic constriction. Accordingly, we assessed the interplay between Myc, substrate oxidation and cardiac function during early pressure overload hypertrophy. Mice with cardiac specific, inducible Myc knockout (MycKO-TAC and non-transgenic littermates (Cont-TAC were subjected to transverse aortic constriction (TAC; n = 7/group. Additional groups underwent sham surgery (Cont-Sham and MycKO-Sham, n = 5 per group. After two weeks, function was measured in isolated working hearts along with substrate fractional contributions to the citric acid cycle by using perfusate with 13C labeled mixed fatty acids, lactate, ketone bodies and unlabeled glucose and insulin. Cardiac function was similar between groups after TAC although +dP/dT and -dP/dT trended towards improvement in MycKO-TAC versus Cont-TAC. In sham hearts, Myc knockout did not affect cardiac function or substrate preferences for the citric acid cycle. However, Myc knockout altered fractional contributions during TAC. The unlabeled fractional contribution increased in MycKO-TAC versus Cont-TAC, whereas ketone and free fatty acid fractional contributions decreased. Additionally, protein posttranslational modifications by O-GlcNAc were significantly greater in Cont-TAC versus both Cont-Sham and MycKO-TAC. In conclusion, Myc alters substrate preferences for the citric acid cycle during early pressure overload hypertrophy without negatively affecting cardiac function. Myc also affects protein posttranslational modifications by O-GlcNAc during hypertrophy, which may regulate Myc-induced metabolic changes.

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

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    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.

  18. Co-overexpression of bcl-2 and c-myc in uterine cervix carcinomas and premalignant lesions

    Directory of Open Access Journals (Sweden)

    Z. Protrka

    2011-03-01

    Full Text Available To establish the role of co-overexpression of bcl-2 and c-myc protooncogenes in uterine cervix carcinogenesis, we examined 138 tissue samples of low grade cervical squamous intraepithelial lesions (SIL, high grade SIL, portio vaginalis uteri (PVU carcinoma in situ and PVU carcinoma invasive, stage IA-IIA (study group and 36 samples without SIL or malignancy (control group. The expression of bcl-2 and c-myc was detected immunohistochemically using a monoclonal antibody. Fisher’s exact test (P<0.05 was used to assess statistical significance. Overexpression of bcl-2 was found to increase in direct relation to the grade of the cervical lesions. High sensitivity was of great diagnostic significance for the detection of these types of changes in the uterine cervix. On the basis of high predictive values it can be said that in patients with bcl-2 overexpression there is a great possibility that they have premalignant or malignant changes in the uterine cervix. Co-overexpression of bcl-2 and c-myc oncogenes was found only in patients with PVU invasive carcinoma (6/26-23.0%. Statistically significant difference was not found in the frequency of co-overexpression in patients with PVU invasive carcinoma in relation to the control group (Fisher’s test; P=0.064. The method's sensitivity of determining these oncogenes with the aim of detecting PVU invasive carcinoma was 23%, while specificity was 72.2%. On the basis of high predictive values (100%, speaking in statistical terms, it can be concluded that all patients with co-overexpression of bcl-2 and c-myc oncogenes will have PVU invasive carcinoma. We confirmed in our research that co-overexpression of bcl-2 and c-myc oncogenes was increased only in PVU invasive carcinoma. However, a more extensive series of samples and additional tests are required to establish the prognostic significance of bcl-2 and c-myc co-overexpression in cervical carcinogenesis.

  19. 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.

  20. Correlation of Epstein-Barr virus and its encoded proteins with Helicobacter pylori and expression of c-met and c-myc in gastric carcinoma

    Institute of Scientific and Technical Information of China (English)

    Bing Luo; Yun Wang; Xiao-Feng Wang; Yu Gao; Bao-Hua Huang; Peng Zhao

    2006-01-01

    AIM: To investigate the interrelationship of Epstein-Barr virus (EBV) and EBV- encoded proteins with Helicobacter pylori (H pylori) infection and the expression of c-met and c-myc oncogene proteins in gastric carcinoma, and to explore their role in gastric carcinogenesis.METHODS: One hundred and eighty-five gastric carcinoma tissues were detected by polymerase chain reaction (PCR)-Southern blot for EBV genome and in situ hybridization (ISH) for EBV-encoded small RNA 1 (EBER1). Gastric carcinoma with positive EBER1 signals was confirmed EBV-associated gastric carcinoma (EBVaGC). The status of H pylori infection in 185 gastric carcinomas was assessed by rapid urease test and PCR.The samples with positive PCR and urease test were defined as H pylori infection. The expression of c-met and c-myc oncogene proteins in tissues of EBVaGC and matched EBV-negative gastric carcinoma (EBVnGC) were examined by immunohistochemistry. RT-PCR and Southern hybridization were used to detect the expression of nuclear antigens (EBNAs) 1 and 2, latent membrane protein (LMP) 1, early genes BARF1 and BHRF1 in EBVaGC cases.RESULTS: The positive rate of H pylori and EBV in 185 gastric carcinomas was 59.45% (110/L85) and 7.03% (13/185) respectively. No difference was found in sex, age, pathological differentiation, clinical stages and lymph node metastasis between H pylori-positive and H pylori-negative gastric carcinomas. However, the positive rate of H pylori infection in the antrum gastric carcinomas was higher than that of cardia and body gastric carcinomas. In our series, age, pathological differentiation, clinical stages, lymph node metastasis and location of cancer were not different between EBVnGC and EBVaGC, while the positive rate of EBV in male patients was significantly higher than that of female patients. The positivity of Hpyloriin EBV-associated and EBV-negative gastric carcinomas was 46.15% (6/13) and 81.40%(104/172) respectively. There was no significant correlation between

  1. 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.

  2. 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.

  3. Targeting C-myc G-Quadruplex: Dual Recognition by Aminosugar-Bisbenzimidazoles with Varying Linker Lengths

    Directory of Open Access Journals (Sweden)

    Nihar Ranjan

    2013-11-01

    Full Text Available G-quadruplexes are therapeutically important biological targets. In this report, we present biophysical studies of neomycin-Hoechst 33258 conjugates binding to a G-quadruplex derived from the C-myc promoter sequence. Our studies indicate that conjugation of neomycin to a G-quadruplex binder, Hoechst 33258, enhances its binding. The enhancement in G-quadruplex binding of these conjugates varies with the length and composition of the linkers joining the neomycin and Hoechst 33258 units.

  4. A natural small molecule, catechol, induces c-Myc degradation by directly targeting ERK2 in lung cancer.

    Science.gov (United States)

    Lim, Do Young; Shin, Seung Ho; Lee, Mee-Hyun; Malakhova, Margarita; Kurinov, Igor; Wu, Qiong; Xu, Jinglong; Jiang, Yanan; Dong, Ziming; Liu, Kangdong; Lee, Kun Yeong; Bae, Ki Beom; Choi, Bu Young; Deng, Yibin; Bode, Ann; Dong, Zigang

    2016-06-07

    Various carcinogens induce EGFR/RAS/MAPK signaling, which is critical in the development of lung cancer. In particular, constitutive activation of extracellular signal-regulated kinase 2 (ERK2) is observed in many lung cancer patients, and therefore developing compounds capable of targeting ERK2 in lung carcinogenesis could be beneficial. We examined the therapeutic effect of catechol in lung cancer treatment. Catechol suppressed anchorage-independent growth of murine KP2 and human H460 lung cancer cell lines in a dose-dependent manner. Catechol inhibited ERK2 kinase activity in vitro, and its direct binding to the ERK2 active site was confirmed by X-ray crystallography. Phosphorylation of c-Myc, a substrate of ERK2, was decreased in catechol-treated lung cancer cells and resulted in reduced protein stability and subsequent down-regulation of total c-Myc. Treatment with catechol induced G1 phase arrest in lung cancer cells and decreased protein expression related to G1-S progression. In addition, we showed that catechol inhibited the growth of both allograft and xenograft lung cancer tumors in vivo. In summary, catechol exerted inhibitory effects on the ERK2/c-Myc signaling axis to reduce lung cancer tumor growth in vitro and in vivo, including a preclinical patient-derived xenograft (PDX) model. These findings suggest that catechol, a natural small molecule, possesses potential as a novel therapeutic agent against lung carcinogenesis in future clinical approaches.

  5. A natural small molecule, catechol, induces c-Myc degradation by directly targeting ERK2 in lung cancer

    Science.gov (United States)

    Lim, Do Young; Shin, Seung Ho; Lee, Mee-Hyun; Malakhova, Margarita; Kurinov, Igor; Wu, Qiong; Xu, Jinglong; Jiang, Yanan; Dong, Ziming; Liu, Kangdong; Lee, Kun Yeong; Bae, Ki Beom; Choi, Bu Young; Deng, Yibin; Bode, Ann; Dong, Zigang

    2016-01-01

    Various carcinogens induce EGFR/RAS/MAPK signaling, which is critical in the development of lung cancer. In particular, constitutive activation of extracellular signal-regulated kinase 2 (ERK2) is observed in many lung cancer patients, and therefore developing compounds capable of targeting ERK2 in lung carcinogenesis could be beneficial. We examined the therapeutic effect of catechol in lung cancer treatment. Catechol suppressed anchorage-independent growth of murine KP2 and human H460 lung cancer cell lines in a dose-dependent manner. Catechol inhibited ERK2 kinase activity in vitro, and its direct binding to the ERK2 active site was confirmed by X-ray crystallography. Phosphorylation of c-Myc, a substrate of ERK2, was decreased in catechol-treated lung cancer cells and resulted in reduced protein stability and subsequent down-regulation of total c-Myc. Treatment with catechol induced G1 phase arrest in lung cancer cells and decreased protein expression related to G1-S progression. In addition, we showed that catechol inhibited the growth of both allograft and xenograft lung cancer tumors in vivo. In summary, catechol exerted inhibitory effects on the ERK2/c-Myc signaling axis to reduce lung cancer tumor growth in vitro and in vivo, including a preclinical patient-derived xenograft (PDX) model. These findings suggest that catechol, a natural small molecule, possesses potential as a novel therapeutic agent against lung carcinogenesis in future clinical approaches. PMID:27167001

  6. c-Myc and AMPK Control Cellular Energy Levels by Cooperatively Regulating Mitochondrial Structure and Function.

    Directory of Open Access Journals (Sweden)

    Lia R Edmunds

    Full Text Available The c-Myc (Myc oncoprotein and AMP-activated protein kinase (AMPK regulate glycolysis and oxidative phosphorylation (Oxphos although often for different purposes. Because Myc over-expression depletes ATP with the resultant activation of AMPK, we explored the potential co-dependency of and cross-talk between these proteins by comparing the consequences of acute Myc induction in ampk+/+ (WT and ampk-/- (KO murine embryo fibroblasts (MEFs. KO MEFs showed a higher basal rate of glycolysis than WT MEFs and an appropriate increase in response to activation of a Myc-estrogen receptor (MycER fusion protein. However, KO MEFs had a diminished ability to increase Oxphos, mitochondrial mass and reactive oxygen species in response to MycER activation. Other differences between WT and KO MEFs, either in the basal state or following MycER induction, included abnormalities in electron transport chain function, levels of TCA cycle-related oxidoreductases and cytoplasmic and mitochondrial redox states. Transcriptional profiling of pathways pertinent to glycolysis, Oxphos and mitochondrial structure and function also uncovered significant differences between WT and KO MEFs and their response to MycER activation. Finally, an unbiased mass-spectrometry (MS-based survey capable of quantifying ~40% of all mitochondrial proteins, showed about 15% of them to be AMPK- and/or Myc-dependent in their steady state. Significant differences in the activities of the rate-limiting enzymes pyruvate kinase and pyruvate dehydrogenase, which dictate pyruvate and acetyl coenzyme A abundance, were also differentially responsive to Myc and AMPK and could account for some of the differences in basal metabolite levels that were also detected by MS. Thus, Myc and AMPK are highly co-dependent and appear to engage in significant cross-talk across numerous pathways which support metabolic and ATP-generating functions.

  7. Deregulated c—myc expression in quiescent CHO cells induces target gene transcription and subsequent apoptotic phenotype

    Institute of Scientific and Technical Information of China (English)

    FANGCHANGMING; CANSHI; 等

    1999-01-01

    Human c-myc cDNA was fused with the hormonebinding domain (HBD) cDNA of murine estrogen receptor gene and the chimeric gene was introduced into the CHO cells.The fusion protein,c-MycER,becomes activated when the synthetic steroid,4-hydroxy-tamoxifen (OHT),binds HBD.Activated c-MycER,likely c-Myc,can induce quiescent CHO cells reentry into S phase and subsequent cell death under serum-free condition.In addition,the expression of some proposed c-myc target genes such as ODC,MrDb,cad,rccl and rcl were found to increase upon OHT induction before S phase entry and apoptosis,indicating that these target genes are involved in cell cycle regulation and/or apoptosis control.However,the mutant D106-143c-MycER protein does not have above activities.

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

    Science.gov (United States)

    2015-10-01

    Oncogenic Pathway in Castration Resistance and Chemoresistance of Prostate Cancer 3 Annual Progress Report W81XWH-13-1-0162 Using a Novel...Transgenic Mouse Model to Study c-Myc Oncogenic Pathway in Castration Resistance and Chemoresistance of Prostate Cancer Feng Yang, Ph.D. Department of...AWARD NUMBER: W81XWH-13-1-0162 TITLE: Using a Novel Transgenic Mouse Model to Study c-Myc Oncogenic Pathway in Castration Resistance and

  9. The immunomodulatory benzodiazepine Bz-423 inhibits B-cell proliferation by targeting c-myc protein for rapid and specific degradation.

    Science.gov (United States)

    Sundberg, Thomas B; Ney, Gina M; Subramanian, Chitra; Opipari, Anthony W; Glick, Gary D

    2006-02-01

    Myc proteins regulate cell growth and are oncogenic in many cancers. Although these proteins are validated molecular anticancer targets, new therapies aimed at modulating myc have yet to emerge. A benzodiazepine (Bz-423) that was discovered in efforts to find new drugs for lupus was found recently to have antiproliferative effects on Burkitt's lymphoma cells. We now show that the basis for the antiproliferative effects of Bz-423 is the rapid and specific depletion of c-myc protein, which is coupled to growth-suppressing effects on key regulators of proliferation and cell cycle progression. c-Myc is depleted as a result of signals coupled to Bz-423 binding its molecular target, the oligomycin sensitivity-conferring protein subunit of the mitochondrial F(1)F(o)-ATPase. Bz-423 inhibits F(1)F(o)-ATPase activity, blocking respiratory chain function and generating superoxide, which at growth-inhibiting concentrations triggers proteasomal degradation of c-myc. Bz-423-induced c-myc degradation is independent of glycogen synthase kinase but is substantially blocked by mutation of the phosphosensitive residue threonine 58, which when phosphorylated targets c-myc for ubiquitination and subsequent proteasomal degradation. Collectively, this work describes a new lead compound, with drug-like properties, which regulates c-myc by a novel molecular mechanism that may be therapeutically useful.

  10. Guttiferone K impedes cell cycle re-entry of quiescent prostate cancer cells via stabilization of FBXW7 and subsequent c-MYC degradation.

    Science.gov (United States)

    Xi, Z; Yao, M; Li, Y; Xie, C; Holst, J; Liu, T; Cai, S; Lao, Y; Tan, H; Xu, H-X; Dong, Q

    2016-06-02

    Cell cycle re-entry by quiescent cancer cells is an important mechanism for cancer progression. While high levels of c-MYC expression are sufficient for cell cycle re-entry, the modality to block c-MYC expression, and subsequent cell cycle re-entry, is limited. Using reversible quiescence rendered by serum withdrawal or contact inhibition in PTEN(null)/p53(WT) (LNCaP) or PTEN(null)/p53(mut) (PC-3) prostate cancer cells, we have identified a compound that is able to impede cell cycle re-entry through c-MYC. Guttiferone K (GUTK) blocked resumption of DNA synthesis and preserved the cell cycle phase characteristics of quiescent cells after release from the quiescence. In vehicle-treated cells, there was a rapid increase in c-MYC protein levels upon release from the quiescence. However, this increase was inhibited in the presence of GUTK with an associated acceleration in c-MYC protein degradation. The inhibitory effect of GUTK on cell cycle re-entry was significantly reduced in cells overexpressing c-MYC. The protein level of FBXW7, a subunit of E3 ubiquitin ligase responsible for degradation of c-MYC, was reduced upon the release from the quiescence. In contrast, GUTK stabilized FBXW7 protein levels during release from the quiescence. The critical role of FBXW7 was confirmed using siRNA knockdown, which impaired the inhibitory effect of GUTK on c-MYC protein levels and cell cycle re-entry. Administration of GUTK, either in vitro prior to transplantation or in vivo, suppressed the growth of quiescent prostate cancer cell xenografts. Furthermore, elevation of FBXW7 protein levels and reduction of c-MYC protein levels were found in the xenografts of GUTK-treated compared with vehicle-treated mice. Hence, we have identified a compound that is capable of impeding cell cycle re-entry by quiescent PTEN(null)/p53(WT) and PTEN(null)/p53(mut) prostate cancer cells likely by promoting c-MYC protein degradation through stabilization of FBXW7. Its usage as a clinical modality to

  11. S-Adenosylmethionine Inhibits the Growth of Cancer Cells by Reversing the Hypomethylation Status of c-myc and H-ras in Human Gastric Cancer and Colon Cancer

    Directory of Open Access Journals (Sweden)

    Jin Luo, Yan-Ni Li, Fei Wang, Wei-Ming Zhang, Xin Geng

    2010-01-01

    Full Text Available A global DNA hypomethylation might activate oncogene transcription, thus promoting carcinogenesis and tumor development. S-Adenosylmethionine (SAM serves as a major methyl donor in biological transmethylation events. The object of this study is to explore the influence of SAM on the status of methylation at the promoter of the oncogenes c-myc, H-ras and tumor-suppressor gene p16 (INK4a, as well as its inhibitory effect on cancer cells. The results indicated that SAM treatment inhibited cell growth in gastric cancer cells and colon cancer cells, and the inhibition efficiency was significantly higher than that in the normal cells. Under standard growth conditions, C-myc and H-ras promoters were hypomethylated in gastric cancer cells and colon cancer cells. SAM treatment resulted in a heavy methylation of these promoters, which consequently downregulated mRNA and protein levels. In contrast, there was no significant difference in mRNA and protein levels of p16 (INK4a with and without SAM treatment. SAM can effectively inhibit the tumor cells growth by reversing the DNA hypomethylation on promoters of oncogenes, thus down-regulating their expression. With no influence on the expression of the tumor suppressor genes, such as P16, SAM could be used as a potential drug for cancer therapy.

  12. 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.

  13. Dichlorodiphenyltrichloroethane technical mixture regulates cell cycle and apoptosis genes through the activation of CAR and ERα in mouse livers

    Energy Technology Data Exchange (ETDEWEB)

    Kazantseva, Yuliya A.; Yarushkin, Andrei A. [Institute of Molecular Biology and Biophysics SB RAMS, Novosibirsk, Timakova str., 2, 630117 (Russian Federation); Pustylnyak, Vladimir O., E-mail: pustylnyak@ngs.ru [Institute of Molecular Biology and Biophysics SB RAMS, Novosibirsk, Timakova str., 2, 630117 (Russian Federation); Novosibirsk State University, Novosibirsk, Pirogova str., 2, 630090 (Russian Federation)

    2013-09-01

    Dichlorodiphenyltrichloroethane (DDT) is a widely used organochlorine pesticide and a xenoestrogen that promotes rodent hepatomegaly and tumours. A recent study has shown significant correlation between DDT serum concentration and liver cancer incidence in humans, but the underlying mechanisms remain elusive. We hypothesised that a mixture of DDT isomers could exert effects on the liver through pathways instead of classical ERs. The acute effects of a DDT mixture containing the two major isomers p,p′-DDT (85%) and o,p′-DDT (15%) on CAR and ERα receptors and their cell cycle and apoptosis target genes were studied in mouse livers. ChIP results demonstrated increased CAR and ERα recruitment to their specific target gene binding sites in response to the DDT mixture. The results of real-time RT-PCR were consistent with the ChIP data and demonstrated that the DDT was able to activate both CAR and ERα in mouse livers, leading to target gene transcriptional increases including Cyp2b10, Gadd45β, cMyc, Mdm2, Ccnd1, cFos and E2f1. Western blot analysis demonstrated increases in cell cycle progression proteins cMyc, Cyclin D1, CDK4 and E2f1 and anti-apoptosis proteins Mdm2 and Gadd45β. In addition, DDT exposure led to Rb phosphorylation. Increases in cell cycle progression and anti-apoptosis proteins were accompanied by a decrease in p53 content and its transcriptional activity. However, the DDT was unable to stimulate the β-catenin signalling pathway, which can play an important role in hepatocyte proliferation. Thus, our results indicate that DDT treatment may result in cell cycle progression and apoptosis inhibition through CAR- and ERα-mediated gene activation in mouse livers. These findings suggest that the proliferative and anti-apoptotic conditions induced by CAR and ERα activation may be important contributors to the early stages of hepatocarcinogenesis as produced by DDT in rodent livers. - Highlights: • DDT activated both CAR and ERα and their cell

  14. 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

  15. Oncogenic K-ras confers SAHA resistance by up-regulating HDAC6 and c-myc expression.

    Science.gov (United States)

    Wang, Qun; Tan, Rong; Zhu, Xin; Zhang, Yi; Tan, Zhiping; Su, Bing; Li, Yu

    2016-03-01

    Histone deacetylase inhibitors (HDIs) represent a new class of anticancer drugs. Suberoylanilide hydroxamic acid (SAHA), the first HDI approved for the treatment of cutaneous T cell lymphoma (CTCL), is currently being tested in clinical trials for other cancers. However, SAHA has been ineffective against solid tumors in many clinical trials. A better understanding of molecular mechanisms of SAHA resistance may provide the basis for improved patient selection and the enhancement of clinical efficacy. Here we demonstrate that oncogenic K-ras contributes to SAHA resistance by upregulating HDAC6 and c-myc expression. We find that the high levels of HDAC6 expression are associated with activated K-ras mutant in colon cancer patients. And expressions of HDAC6 and c-myc are increased in fibroblasts transformed with activated K-ras. Surprisingly, we find that activated K-ras transformed cells are more resistant to SAHA inhibition on cell growth and anchorage-independent colony formation. We show that a K-ras inhibitor sensitizes K-ras mutated lung cancer cells to SAHA induced growth inhibition. We also find that mutant K-ras induces HDAC6 expression by a MAP kinase dependent pathway. Our study suggests that combined treatment with SAHA and K-ras inhibitors may represent an effective strategy to overcome SAHA resistance.

  16. C-MYC-induced upregulation of lncRNA SNHG12 regulates cell proliferation, apoptosis and migration in triple-negative breast cancer.

    Science.gov (United States)

    Wang, Ouchen; Yang, Fan; Liu, Yehuan; Lv, Lin; Ma, Ruimin; Chen, Chuanzhi; Wang, Jiao; Tan, Qiufan; Cheng, Yue; Xia, Erjie; Chen, Yizuo; Zhang, Xiaohua

    2017-01-01

    Triple-negative breast cancer (TNBC) is one of the most aggressive subtypes of breast cancer, with a significantly higher recurrence and mortality rate. There is an urgent need to uncover the mechanism underlying TNBC and establish therapeutic targets. Long non-coding RNAs (lncRNAs) are involved in a series of biological functions and provide novel insights into the molecular mechanism of cancer. Based on their expression specificity and large number, lncRNAs are likely to serve as the basis for clinical applications in oncology. In our previous study, we utilized RNA sequencing (RNA-seq) to explore the lncRNAs expression profiles in TNBC and identified that small nucleolar RNA host gene 12 (SNHG12) was remarkably increased in TNBC. However, the role of SNHG12 in TNBC has not been clarified. Herein, we determine that SNHG12 is upregulated in TNBC, and its high expression is significantly correlated with tumor size and lymph node metastasis. Mechanistic investigations show that SNHG12 is a direct transcriptional target of c-MYC. Silencing SNHG12 expression inhibits TNBC cells proliferation and apoptosis promotion, whereas SNHG12 overexpression has the opposite effect. In addition, we reveal that SNHG12 may promote cells migration by regulating MMP13 expression. To the best of our knowledge, it is the first report indicating that SNHG12 is involved in breast cancer. Taken together, our findings suggest that SNHG12 contributes to the oncogenic potential of TNBC and may be a promising therapeutic target.

  17. 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, Pcycle and increased cell numbers (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.

  18. Critical Role of c-Myc in Acute Myeloid Leukemia Involving Direct Regulation of miR-26a and Histone Methyltransferase EZH2

    Science.gov (United States)

    Salvatori, Beatrice; Iosue, Ilaria; Djodji Damas, Nkerorema; Mangiavacchi, Arianna; Chiaretti, Sabina; Messina, Monica; Padula, Fabrizio; Guarini, Anna; Bozzoni, Irene; Fazi, Francesco; Fatica, Alessandro

    2011-01-01

    Increased expression or aberrant activation of c-Myc plays an important role in leukemogenesis. Here, we show that in acute myeloid leukemia (AML), c-Myc directly controls the expression of EZH2, a component of the Polycomb repressive complex 2, and miR-26a. miR-26a is downregulated in primary blasts from AML patients and, during myeloid differentiation of AML cells, is induced together with a decrease in c-Myc and Ezh2 levels. Previously, EZH2 was shown to be regulated by miR-26a at the translational levels in lymphomas. However, we demonstrate that in AML, the variation of EZH2 mainly depends on c-Myc transcriptional control. We also show that enforced expression of miR-26a in AML cells is able to inhibit cell cycle progression by downregulating cyclin E2 expression. In addition, increased levels of miR-26a potentiate the antiproliferative effects of 1,25-dihydroxyvitamin D3 (VitD) and stimulate myeloid differentiation. Our results identify new molecular targets of c-Myc in AML and highlight miR-26a attractiveness as a therapeutic target in leukemia. PMID:21901171

  19. Local Delivery of C-myc Antisense Oligodeoxynucleotide by Gelatin Coated Platinium-Iridium Stent to Prevent Restenosis in a Normal Rabbit Carotid Artery

    Institute of Scientific and Technical Information of China (English)

    Zhang Xinxia; Wei Wenbin; Duan Wen; Xu Xiangguang; Hu Xuesong

    2005-01-01

    Objectives To investigate the feasibility and effect of local deliveryof c-myc antisense oligodeoxynucleotide (ASODN) by gelatin coated Platinium-Iridium stent to prevent restenosis in a normal rabbit carotid artery. Methods Gelatin coated Platinium-Iridium stent were implanted in the right carotid arteries of 32 rabbits under vision. Animals were randomized to the control group and the treated group receiving c-myc ASODN (n=16 respectively).7,14,30,90 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 methods. Results 32 stents were successfully implanted into the right carotid arteries in 32 animals. Morphometric analysis showed that neointimal area and mean neointimal thickness siginificantly increased continuously up to 12 weeks after stent implantation,and at each time point ,neointimal area and mean neointimal thickness were siginificantly smaller in the treated group than control group. (P<0.001 ,respectively).c-myc protein expression was weak positive or negative in treated group and positive in control group. Conclusions Gelatin coated Platinium-Iridium stent mediated local delivery of c-myc ASODN is feasibility , and it can inhibit neointimal hyperplasia to prevent restenosis in a normal rabbit carotid artery.

  20. Expressions of beta-catenin, APC Protein, C-myc and Cyclin D1 in Ovarian Epithelial Tumor and Their Implication

    Institute of Scientific and Technical Information of China (English)

    LIN Xiao; LI Yu; MI Can

    2007-01-01

    Objective: To investigate the expressions of beta-catenin, protein APC (adenomatous polyposis coli protein), c-myc and cyclin D1 and their implication in ovarian epithelial tumor. Methods: Immunohistochemical staining with SP method was conducted to identify the expressions of beta-catenin, APC protein, c-myc and cyclin D1 in ovarian epithelial tumor in 48 cases. Results: The abnormal expression rate of beta-catenin in malignant and borderline ovarian epithelial tumors was higher than that in benign epithelial tumors (P<0.01). The expression rates of c-myc and cyclin-D1 in ovarian malignant and borderline epithelial tumors were higher than those in benign epithelial tumors too(P<0.05). The prevalence of APC protein positive expression in benign epithelial tumors were significantly greater than that in malignant epithelial tumors (P<0.05). A significant negative correlation was found between beta-catenin and APC protein in ovarian epithelial tumors; while a significant positive correlation was found between beta-catenin, c-myc and cyclin-D1 in ovarian epithelial tumor (P<0.05). Conclusion: The abnormal expressions of Beta-catenin, APC protein, c-myc and cyclin-D1 might be used to indicate the malignance transform of ovarian epithelial tumors.

  1. c-Myc-miR-29c-REV3L signalling pathway drives the acquisition of temozolomide resistance in glioblastoma.

    Science.gov (United States)

    Luo, Hui; Chen, Zhengxin; Wang, Shuai; Zhang, Rui; Qiu, Wenjin; Zhao, Lin; Peng, Chenghao; Xu, Ran; Chen, Wanghao; Wang, Hong-Wei; Chen, Yuanyuan; Yang, Jingmin; Zhang, Xiaotian; Zhang, Shuyu; Chen, Dan; Wu, Wenting; Zhao, Chunsheng; Cheng, Gang; Jiang, Tao; Lu, Daru; You, Yongping; Liu, Ning; Wang, Huibo

    2015-12-01

    Resistance to temozolomide poses a major clinical challenge in glioblastoma multiforme treatment, and the mechanisms underlying the development of temozolomide resistance remain poorly understood. Enhanced DNA repair and mutagenesis can allow tumour cells to survive, contributing to resistance and tumour recurrence. Here, using recurrent temozolomide-refractory glioblastoma specimens, temozolomide-resistant cells, and resistant-xenograft models, we report that loss of miR-29c via c-Myc drives the acquisition of temozolomide resistance through enhancement of REV3L-mediated DNA repair and mutagenesis in glioblastoma. Importantly, disruption of c-Myc/miR-29c/REV3L signalling may have dual anticancer effects, sensitizing the resistant tumours to therapy as well as preventing the emergence of acquired temozolomide resistance. Our findings suggest a rationale for targeting the c-Myc/miR-29c/REV3L signalling pathway as a promising therapeutic approach for glioblastoma, even in recurrent, treatment-refractory settings.

  2. 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

    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 cMyc...... and simultaneously induced miR-125b-5p that exerted a cytoprotective effect through the downmodulation of MAD4. Overexpression of cMyc repressed miR-125b-5p transcription and sensitized lymphoma cells to bortezomib. The central role of miR-125b-5p was further confirmed in a mouse model of T-cell lymphoma, where...

  3. Resistance to arginine deiminase treatment in melanoma cells is associated with induced argininosuccinate synthetase expression involving c-Myc/HIF-1alpha/Sp4.

    Science.gov (United States)

    Tsai, Wen-Bin; Aiba, Isamu; Lee, Soo-yong; Feun, Lynn; Savaraj, Niramol; Kuo, Macus Tien

    2009-12-01

    Arginine deiminase (ADI)-based arginine depletion is a novel strategy under clinical trials for the treatment of malignant melanoma with promising results. The sensitivity of melanoma to ADI treatment is based on its auxotrophy for arginine due to a lack of argininosuccinate synthetase (AS) expression, the rate-limiting enzyme for the de novo biosynthesis of arginine. We show here that AS expression can be transcriptionally induced by ADI in melanoma cell lines A2058 and SK-MEL-2 but not in A375 cells, and this inducibility was correlated with resistance to ADI treatment. The proximal region of the AS promoter contains an E-box that is recognized by c-Myc and HIF-1alpha and a GC-box by Sp4. Through ChIP assays, we showed that under noninduced conditions, the E-box was bound by HIF-1alpha in all the three melanoma cell lines. Under arginine depletion conditions, HIF-1alpha was replaced by c-Myc in A2058 and SK-MEL-2 cells but not in A375 cells. Sp4 was constitutively bound to the GC-box regardless of arginine availability in all three cell lines. Overexpressing c-Myc by transfection upregulated AS expression in A2058 and SK-MEL-2 cells, whereas cotransfection with HIF-1alpha suppressed c-Myc-induced AS expression. These results suggest that regulation of AS expression involves interplay among positive transcriptional regulators c-Myc and Sp4, and negative regulator HIF-1alpha that confers resistance to ADI treatment in A2058 and SK-MEL-2 cells. Inability of AS induction in A375 cells under arginine depletion conditions was correlated by the failure of c-Myc to interact with the AS promoter.

  4. Determination of Mutation of C-myc Oncogene in Gastric Cancer by Capillary Electrophoresis%毛细管电泳法检测癌基因C-myc胃癌中基因点突变

    Institute of Scientific and Technical Information of China (English)

    谢希晖; 王荣; 贾正平; 谢华; 张爱梅; 徐娟; 王晓莉; 王先华

    2011-01-01

    gene is 20. 0% (10/50). Sequence analysis further identified a point mutation of A to T in exon 2 codon 53 (GAT→GTT), causing an amino acid substitution of leucine to glutamine. This study may suggest a correlation of the mutation of C-myc oncogene with gastric cancer progression. This work also demonstrates that CE can offer a convenient and reliable method to early diagnosis of gastric cancer.

  5. Gene expression profiling of MYC-driven tumor signatures in porcine liver stem cells by transcriptome sequencing

    Science.gov (United States)

    It is now well-established that cancer stem cells (CSCs) drive tumor growth and that the cancer gene, c-Myc, plays a critical role in converting cells to CSCs. However, little is known about the genes that are induced and regulated by c-Myc to generate tumors, and, in particular, tumors of the live...

  6. 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.

  7. Hans, Choi immunophenotyping and C-MYC genetic features between pediatric and adult diffuse large B-cell lymphoma%儿童与成人弥漫大B细胞淋巴瘤的Hans、Choi免疫分型和C-MYC基因特征

    Institute of Scientific and Technical Information of China (English)

    徐红艳; 黄慧; 杨文萍; 黄传生; 钟梅慧

    2013-01-01

    Objective To explore the difference of Hans,Choi immunophenotyping and C-MYC gene characteristics between pediatric and adult diffuse large B-cell lymphoma.Methods To collect 60 cases of DLBCL clinicopathological data and follow-up,which contained 17 cases of children group,adult group of 43 patients.To observe CD10,BCL-6,MUM1,FOXP1,GCET1 and CD5 protein expression by immunohistochemical SP method and evaluated by Hans and Choi immunophenotyping standard genotyping.To detect C-MYC gene circumstances by interphase fluorescence insituhybridization (FISH).Results 1) Hans typing:the Children DLBCL group of GCB were 11 cases,non-GCB type were 6 cases; the GCB type in the adult DLBCL group were nine cases,non-GCB type were 34 cases.2)Choi typing:the Children DLBCL group of GCB type were 13 cases,ABC type were 4 cases; the adult DLBCL group of GCB type were 13 cases,ABC type were 30 cases (P < 0.01).3) C-MYC gene:The C-MYC gene disruption of children DLBCL were 5 cases; C-MYC gene in 43 adult cases were normal(P <0.01).Conclusions Child DLBCL of GCB-type with better prognosis while but non-GCB-type predict worse prognosis.The C-MYC gene disruption in Children DLBCL was significantly higher than that of adult ones.%目的 探讨弥漫大B细胞淋巴瘤(DLBCL)各年龄组的Hans、Choi免疫分型及C-MYC基因特征.方法 收集60例DLBCL临床病理资料并进行随访,其中儿童组17例、成人组43例.用免疫组化SP法观察CD10、BCL-6、MUM1、FOXP1、GCET1及CD5蛋白表达,根据Hans及Choi免疫分型标准分型;用间期荧光原位杂交法检测C-MYC 基因.结果 1)Hans分型:儿童DLBCL组GCB型11例,non-GCB型6例;成人组DLBCL中GCB型9例,non-GCB型34例(P<0.05).2) Choi分型:儿童DLBCL组GCB型13例,ABC型4例;成人DLBCL组GCB型13例,ABC型30例(P<0.01).3) C-MYC基因:儿童组DLBCL中C-MYC基因断裂6例;成人组DLBCL中C-MYC基因正常43例(P<0.01).结论 儿童DLBCL以GCB型为主,预后较好;成人DLBCL以non-GCB

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

    Directory of Open Access Journals (Sweden)

    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.

  9. Effects of matrine on the growth inhibition, c-myc and hTERT protein expression in human adenocarcinoma lung cancer cell line A549

    Directory of Open Access Journals (Sweden)

    Qiong CHEN

    2008-08-01

    Full Text Available Background and objective It was reported that telomerase was associated with the oncogenesis and progression of cancer, and to be the common targets of cancer therapy. The mechanism of matrine on lung cancer in vitro is not clear. We studied the effect of matrine on growth of human lung adenocarcinoma A549 cells and the mechanism related with telomerase. Methods MTT was used for measuring A549 cells viability, Hoechst 33342-propidium iodide fluorescent staining for observing apoptotic cells, flow cytometry (FCM for analyzing cell cycle and apoptosis, and immunocytochemistry for measuring the protein expressions of c-myc and hTERT in A549 cells. Results Matrine inhibited the proliferation of A549 cells with a time-dose-dependent manner (P<0.05. Hoechst 33342-propidium iodide staining showed apoptotic cells with chromatin condensation and fragmentation of nuclei. FCM analysis indicated elevating rate of cells in G0/G1 phase, lowering rate of that in S phase and the highering apoptotic rate. The levels of c-myc and hTERT protein expression in the matrine group was lower than that in the control group (P<0.05, and AOD of c-myc showed positive correlation with AOD of hTERT (r=0.633, P<0.01 Conclusion The inhibitory effect of matrine on A549 cells may be related to the lower expression of c-myc and hTERT.

  10. Effect of Neem Leaf Extract (Azadirachta indica on c-MycOncogene Expression in 4T1 Breast Cancer Cells of BALB/c Mice

    Directory of Open Access Journals (Sweden)

    Chong Pei Pei

    2012-01-01

    Full Text Available Objective: Breast cancer is the most common cause of cancer-related deaths in women both worldwide and in Malaysia. Azadirachta indica (A. Juss, commonly known as neem, is one of the most versatile medicinal plants that has gained worldwide prominence due to its medicinal properties. However, the anticancer effect of ethanolic neem leaf extract against breast cancer has not been documented. The purpose of the present study is to investigate the effect of neem leaf extract on c-Myc oncogene expression in 4T1 breast cancer BALB/c mice.Materials and Methods: In this experimental study, A total of 48 female BALB/c mice were divided randomly into four groups of 12 mice per group: i.cancer control (CC treated with 0.5% Tween 20 in PBS, ii. 0.5 μg/mL tamoxifen citrate (CT, iii. 250 mg/kg neem leaf extract (C250, and iv. 500 mg/kg neem leaf extract (C500. In situ reverse transcription polymerase chain reaction (in situ RT-PCR was applied to evaluate suppression of c-Myc oncogene expression in breast cancer tissue.Results: The C500 group showed significant (p<0.05 suppression of c-Myc oncogene expression compared to the CC group.Conclusion: c-Myc was found to be down regulated under the effect of 500 mg/kg ethanolicneem leaf extract.

  11. Function of apoptosis and expression of the proteins Bcl-2, p53 and C-myc in the development of gastric cancer

    Institute of Scientific and Technical Information of China (English)

    An Gao Xu; Shao Guang Li; Ji Hong Liu; Ai Hua Gan

    2001-01-01

    @@INTRODUCTION In China ,the incidence and mortality of gastric cancer rank the second among all cancers. Recent development of cancer [1-20].The aim of this study was investigat the insight of apoptosis and bcl-2, p53 and C-myc protein expression in the development of gastric cancer .

  12. THE HEPARIN-BINDING DOMAIN AND V REGION OF FIBRONECTIN REGULATE APOPTOSIS BY SUPPRESSION OF P53 AND C-MYC IN HUMAN PRIMARY CELLS

    Science.gov (United States)

    In apoptosis the tumor suppressor p53 and oncogene c-myc, are usually upregulated. However, we report here an alternate pathway of regulation that is triggered by inflammatory-associated matrix fragments of fibronectin (FN) and leads to apoptosis. It is mediated by transcriptio...

  13. Pokemon、c-myc在结直肠癌中的表达及意义%EXPRESSION AND CLINICAL SIGNIFICANCE OF POKEMON AND C-MYC IN COLORECTAL CANCER

    Institute of Scientific and Technical Information of China (English)

    刘叔敏; 范玉磊; 梁婷婷; 孙影

    2014-01-01

    目的:探讨结直肠癌组织Pokemon和c-myc蛋白表达的变化和意义。方法:SP免疫组化法检测60例结直肠癌组织和癌旁正常组织Pokemon和c-myc蛋白的表达情况。结果:结直肠癌组织Pokemon和c-myc蛋白的阳性表达率均明显高于正常组织(P<0.01);结直肠癌组织Pokemon和c-myc蛋白的阳性表达与分化程度、Dukes分期和淋巴结转移有关(P<0.01,P<0.05);结直肠癌组织中,Pokemon和c-myc蛋白的表达呈显著正相关(r=0.615,P<0.05)。结论:Pokemon和c-myc对结直肠癌的诊断和预后评判具有一定的价值。%Objective: To investigate the expression and clinical significance of Pokemon and c-myc in human colorectal cancer.Methods: SP immunohistochemical staining was used to detect the expression of Pokemon and c-myc in 60 cases colorectal cancer and matched para-carcinoma tissues.Results:The positive expression rate of Pokemon and c-myc in colorectal cancer were obviously higher than that in normal tissue (P<0.01). In colorectal cancer, the positive expression of Pokemon and c-myc were related with differentiation degree, Dukes stage and lymph node metastasis (P<0.01,P<0.05). The positive expression of Pokemon in colorectal cancer was positively correlated with c-myc expression (r=0.615,P<0.05). Conclusions: Pokemon and c-myc have certain value for diagnosing and prognosis of colorectal cancer.

  14. Effect of Qi-protecting powder (Huqi San) on expression of c-jun, c-fos and c-myc in diethylnitrosamine-mediated hepatocarcinogenesis

    Institute of Scientific and Technical Information of China (English)

    Xia Li; Zheng-Ming Shi; Ping Feng; Zhao-Yang Wen; Xue-Jiang Wang

    2007-01-01

    AIM: To study the inhibitory effect of Huqi San (Qiprotecting powder) on rat prehepatocarcinoma induced by diethylinitrosamine (DEN) by analyzing the mutational activation of c-fos proto-oncogene and over-expression of c-jun and c-myc oncogenes.METHODS: A Solt-Farber two-step test model of prehepatocarcinoma was induced in rats by DEN and 2-acetylaminofluorene (AAF) to investigate the modifying effects of Huqi San on the expression of c-jun, c-fos and c-myc in DEN-mediated hepatocarcinogenesis. Huqi San was made of eight medicinal herbs containing glycoprival granules, in which each milliliter contains 0.38 g crude drugs. γ-glutamy-transpeptidase-isoenzyme (γ-GTase)was determined with histochemical methods. Level of 8-hydroxydeoxyguanosine (OHdG) formed in liver and c-jun, c-fos and c-myc proto-oncogenes were detected by immunohistochemical methods.RESULTS: The level of 8-OHdG, a mark of oxidative DNA damage, was significantly decreased in the liver of rats with prehepatocarcinoma induced by DEN who received 8 g/kg body weight or 4 g/kg body weight Huqi San before (1 wk) and after DEN exposure (4 wk). Huqi Santreated rats showed a significant decrease in number of γ-GT positive foci (P < 0.001, prevention group: 4.96 ±0.72 vs 29.46 ± 2.17; large dose therapeutic group: 7.53± 0.88 vs 29.46 ± 2.17). On the other hand, significant changes in expression of c-jun, c-fos and c-myc were found in Huqi San-treated rats.CONCLUSION: Activation of c-jun, c-fos and c-myc plays a crucial role in the pathogenesis of liver cancer.Huqi San can inhibit the over-expression of c-jun, c-fos and c-myc oncogenes and liver preneolastic lesionsinduced by DEN.

  15. The function of apoptosis and protein expression of bcl-2, p53 and C-myc inthe development of gastric cancer

    Institute of Scientific and Technical Information of China (English)

    An Gao Xu; Shao Guang Li; Ji Hong Liu; Ai Hua Gan

    2000-01-01

    AIM To understand the rule and possible function of apoptosis and protein expression of bcl-2, p53 and C-myc in chronic gastritis, gastric ulcer, non-classic proliferation of gastric mucosa and gastric cancer.METHODS Apoptosis was detected by using in situ terminal labelling (TUNEL). The protein expression ofbcl-2, p53 and C-myc was detected by immunohistochemical method.RESULTS The indexes of apoptosis in chronic active gastritis, gastric ulcer, mild and severe non-classicproliferation of gastric mucosa, early and progressive gastric cancer were 16.8%±12.3%, 24.1%±20.0%,19.3%±16.4%, 15.7%±15.2%, 10.1%±9.1% and 6.3%±6.0%, respectively. The index of progressivegastric cancer was lower than that of early gastric cancer and non-classic proliferation of gastric mucosa(P<0.05). The positive rate of bcl-2 protein was 9.4%, 27.6%, 52.9%, 75.0%, 83.3% and 46.7%,respectively. The positive rate of bcl-2 of early gastric cancer was higher than that of progressive gastriccancer. The positive rates of p53 protein of severe non-classic proliferation, early and progressive gastriccancer were 25.0%, 33.3% and 63.3%, respectively. The positive rate of p53 of progressive gastric cancerwas higher than that of early gastric cancer and non-classic proliferation (P<0.05). In Lauren types, theindex of apoptosis, protein expression rates of bcl-2, p53 and C-myc of intestinal type were 8.3%±7.2%,38.9%, 77.7% and 56.6%, while that of diffuse type were 5.1%±4.9%, 58.3%, 50.0% and 8.3%,respectively. All markers had statistical difference between two types (P<0.05).CONCLUSION Apoptosis was inhibited stepwise in the development of non-classic proliferation of gastricmucosa to early gastric cancer and then to progressive gastric cancer. The high expression of bcl-2, p53 andC-myc was related to the development of gastric cancer, bcl-2 might play an important role in early gastriccancer while p53 and C-myc act mostly in middle and late stage gastric cancer. The Lauren typing of

  16. Assessment of the effect of betaine on p16 and c-myc DNA methylation and mRNA expression in a chemical induced rat liver cancer model

    Directory of Open Access Journals (Sweden)

    Ling Wen-hua

    2009-07-01

    Full Text Available Abstract Background The development and progression of liver cancer may involve abnormal changes in DNA methylation, which lead to the activation of certain proto-oncogenes, such as c-myc, as well as the inactivation of certain tumor suppressors, such as p16. Betaine, as an active methyl-donor, maintains normal DNA methylation patterns. However, there are few investigations on the protective effect of betaine in hepatocarcinogenesis. Methods Four groups of rats were given diethylinitrosamine (DEN and fed with AIN-93G diets supplemented with 0, 10, 20 or 40 g betaine/kg (model, 1%, 2%, and 4% betaine, respectively, while the control group, received no DEN, fed with AIN-93G diet. Eight or 15 weeks later, the expression of p16 and c-myc mRNA was examined by Real-time PCR (Q-PCR. The DNA methylation status within the p16 and c-myc promoter was analyzed using methylation-specific PCR. Results Compared with the model group, numbers and areas of glutathione S-transferase placental form (GST-p-positive foci were decreased in the livers of the rats treated with betaine (P . Although the frequency of p16 promoter methylation in livers of the four DEN-fed groups appeared to increase, there is no difference among these groups after 8 or 15 weeks (P > 0.05. Betaine supplementation attenuated the down-regulation of p16 and inhibited the up-regulation of c-myc induced by DEN in a dose-dependent manner (P P . Finally, enhanced antioxidative capacity (T-AOC was observed in both the 2% and 4% betaine groups. Conclusion Our data suggest that betaine attenuates DEN-induced damage in rat liver and reverses DEN-induced changes in mRNA levels.

  17. Oxidative damage, pro-inflammatory cytokines, TGF-α and c-myc in chronic HCV-related hepatitis and cirrhosis

    Institute of Scientific and Technical Information of China (English)

    Fabio Farinati; Romilda Cardin; Marina Bortolami; Maria Guido; Massimo Rugge

    2006-01-01

    AIM: To assess whether a correlation exists between oxidative DNA damage occurring in chronic HCV-relatecl hepatitis and expression levels of pro-inflammatory cytokines, TGF-α and c-myc.METHODS: The series included 37 patients with chronic active HCV-related hepatitis and 11 with HCV-related compensated cirrhosis. Eight-hydroxydeoxyguanosine in liver biopsies was quantified using an electrochemical detector. The mRNA expression of TNF-α, IL-1β, TGF-αand c-myc in liver specimens was detected by semiquantitative comparative RT-PCR.RESULTS: TNF-α levels were significantly higher in hepatitis patients than in cirrhosis patients (P=0.05).IL-1β was higher in cirrhosis patients (P=0.05). A significant correlation was found between TNF-α and staging (P=0.05) and between IL-1β levels and grading (P= 0.04). c-myc showed a significantly higher expression in cirrhosis patients (P=0.001). Eight-hydroxydeoxyguanosine levels were significantly higher in cirrhosis patients (P=0.05) and in HCV genotype 1. (P=0.03).Considering all patients, 8-hydroxydeoxyguanosine levels were found to be correlated with genotype (P=0.04)and grading (P=0.007). Also multiple logistic regression analysis demonstrated a significant correlation among the number of DNA adducts, TNF-α expression and HCV genotype (P= 0.02).CONCLUSION: In chronic HCV-related liver damage, oxidative DNA damage correlates with HCV genotype, grading and TNF-α levels. As HCV-related liver damage progresses, TNF-α levels drop while IL-1β and c-myc levels increase, which may be relevant to liver carcinogenesis.

  18. CyclinA、C-myc在皮肤瘢痕及瘢痕癌组织中的表达及意义%Expressions and Significance of CyclinA and C-myc in Skin Scar and Skin Scar Carcinoma

    Institute of Scientific and Technical Information of China (English)

    郭瑞珍; 周开梅; 王燕

    2011-01-01

    . Compared with normal skin group and skin scar group ,the expression (optical density and positive area) of CyclinA and its mRNA in scar carcinoma group were statistically significant (P<0. 01). No statistic differences oftheir expression were measured between normal skin epidermis and pathological skin scar epithelium. (2) C-myc protein showed strong positive, positive and weakly positive expression in scar carcinoma tissues, pathological skin scar epithelium and normal skin epidermis respectively. Each of two groups was statistically different(P<0. 05). (3)Correlated analysis showed that there was positive correlation between the expression levels of CyclinA and CyclinA mRNA, CyclinA and C-myc proteins in skin scar carcinoma tissues. Conclusion (l)The high expression of CyclinA,CyclinA mRNA and C-myc may be related to the occurrence of skin scar carcinoma. (2)The high expression of C-myc may be related to the cancerization of skin scar epithelium. (3)There was the abnormal expression of CyclinA not only on protein levels, but also on gene levels in skin scar carcinoma tissues.

  19. HSPH1 inhibition downregulates Bcl-6 and c-Myc and hampers the growth of human aggressive B-cell non-Hodgkin lymphoma.

    Science.gov (United States)

    Zappasodi, Roberta; Ruggiero, Giusi; Guarnotta, Carla; Tortoreto, Monica; Tringali, Cristina; Cavanè, Alessandra; Cabras, Antonello D; Castagnoli, Lorenzo; Venerando, Bruno; Zaffaroni, Nadia; Gianni, Alessandro M; De Braud, Filippo; Tripodo, Claudio; Pupa, Serenella M; Di Nicola, Massimo

    2015-03-12

    We have shown that human B-cell non-Hodgkin lymphomas (B-NHLs) express heat shock protein (HSP)H1/105 in function of their aggressiveness. Here, we now clarify its role as a functional B-NHL target by testing the hypothesis that it promotes the stabilization of key lymphoma oncoproteins. HSPH1 silencing in 4 models of aggressive B-NHLs was paralleled by Bcl-6 and c-Myc downregulation. In vitro and in vivo analysis of HSPH1-silenced Namalwa cells showed that this effect was associated with a significant growth delay and the loss of tumorigenicity when 10(4) cells were injected into mice. Interestingly, we found that HSPH1 physically interacts with c-Myc and Bcl-6 in both Namalwa cells and primary aggressive B-NHLs. Accordingly, expression of HSPH1 and either c-Myc or Bcl-6 positively correlated in these diseases. Our study indicates that HSPH1 concurrently favors the expression of 2 key lymphoma oncoproteins, thus confirming its candidacy as a valuable therapeutic target of aggressive B-NHLs.

  20. cMyc/miR-125b-5p signalling determines sensitivity to bortezomib in preclinical model of cutaneous T-cell lymphomas.

    Directory of Open Access Journals (Sweden)

    Valentina Manfè

    Full Text Available 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 cMyc and simultaneously induced miR-125b-5p that exerted a cytoprotective effect through the downmodulation of MAD4. Overexpression of cMyc repressed miR-125b-5p transcription and sensitized lymphoma cells to bortezomib. The central role of miR-125b-5p was further confirmed in a mouse model of T-cell lymphoma, where xenotransplantation of human CTCL cells overexpressing miR-125b-5p resulted in enhanced tumor growth and a shorter median survival. Our findings describe a novel mechanism through which miR-125b-5p not only regulates tumor growth in vivo, but also increases cellular resistance to proteasome inhibitors via modulation of MAD4.

  1. A Novel PTEN/Mutant p53/c-Myc/Bcl-XL Axis Mediates Context-Dependent Oncogenic Effects of PTEN with Implications for Cancer Prognosis and Therapy

    Directory of Open Access Journals (Sweden)

    Xiaoping Huang

    2013-08-01

    Full Text Available Phosphatase and tensin homolog located on chromosome 10 (PTEN is one of the most frequently mutated tumor suppressors in human cancer including in glioblastoma. Here, we show that PTEN exerts unconventional oncogenic effects in glioblastoma through a novel PTEN/mutant p53/c-Myc/Bcl-XL molecular and functional axis. Using a wide array of molecular, genetic, and functional approaches, we demonstrate that PTEN enhances a transcriptional complex containing gain-of-function mutant p53, CBP, and NFY in human glioblastoma cells and tumor tissues. The mutant p53/CBP/NFY complex transcriptionally activates the oncogenes c-Myc and Bcl-XL, leading to increased cell proliferation, survival, invasion, and clonogenicity. Disruption of the mutant p53/c-Myc/Bcl-XL axis or mutant p53/CBP/NFY complex reverses the transcriptional and oncogenic effects of PTEN and unmasks its tumor-suppressive function. Consistent with these data, we find that PTEN expression is associated with worse patient survival than PTEN loss in tumors harboring mutant p53 and that a small molecule modulator of p53 exerts greater antitumor effects in PTEN-expressing cancer cells. Altogether, our study describes a new signaling pathway that mediates context-dependent oncogenic/tumor-suppressive role of PTEN. The data also indicate that the combined mutational status of PTEN and p53 influences cancer prognosis and anticancer therapies that target PTEN and p53.

  2. The c-myc mRNA and helicobacter pylori infection and the relationship between the programmed cell death in the with Gastric cancer in the patients with gastric cancer%胃癌变患者c-myc mRNA与幽门螺杆菌感染及细胞程序性死亡的关系

    Institute of Scientific and Technical Information of China (English)

    潘晟; 罗浩; 李力

    2013-01-01

    Objective To discuss different stomach trouble change occurred in the process of development until the progression in patients with c-myc mRNA expression in correlation with helicobacter pylori (Hp) infection and its relationship with gastric tissue programmed cell death.Methods By real-time fluorescent quantitative reverse transcription-olymerase chain reaction (FQ-PCR) to detect 72 cases of chronic superficial gastritis (CSG),55 cases of chronic atrophic gastritis (the CAG),52 cases of intestinal metaplasia (IM),46 cases of atypical hyperplasia (AH),65 cases of gastric cancer (GC) group (CSG group,respectively,the CAG group,IM,AM group,AH,the GC group) in the c-myc mRNA expression;Rapid enzymatic urea,Warthin Starry silver staining and toluidine blue staining assay for gastric mucosa Hp infection;In situ end labeling (TUNEL) method to detect gastric mucosal cell apoptosis index (AI).Results CSG group,the CAG group,IM,AM group,AH,the GC group c-myc in gastric mucosa tissue mRNA positive example were 21.5% (7/31),31.0% (8/27),41.0% (10/26),59.1% (14/24) and 69.1 (23/33),c-myc relative mRNA expression levels were 0.089 ± 0.002,0.01 13 ± 0.014 mm,0.168 ±0.028,0.226,0.367 ±0.037 mm,0.040 mm IM,AH group,GC group c-myc amount of mRNA expression were higher than in CSG,the CAG group (P < 0.01),the AH group is higher than the IM group (P <0.01),the GC group higher than IM,AH group (P <0.01).C-myc mRNA expression quantity and negatively correlated with gastric mucosa cells AI (rs =-0.700,P <0.05) ;IM,AH group,GC group Hp positive patients with gastric mucosa cell c-myc mRNA expression were higher than Hp negative patients (P <0.05 or 0.01).Conclusion In the process of the gastric mucosal canceration,Hp infection can increase gastric mucosa cell c-myc mRNA expression,and inhibition of special-shaped programmed cell death (apoptosis) and play a role of cancer.%目的 探讨不同胃病变患者的发生发展直至恶变过程中c-myc mRNA的表达与

  3. 艾灸对实验性类风湿关节炎滑膜细胞原癌基因 c-fos和c-myc mRNA表达的影响%Effects of moxibustion on the expression of protooncogene c-fos and c-myc mRNA in experimental arthritis

    Institute of Scientific and Technical Information of China (English)

    余俊辉; 刘旭光; 余曙光; 蔡美英; 周昌华; 赵宗蓉; 张平

    2005-01-01

    目的观察艾灸对实验性类风湿关节炎滑膜细胞原癌基因c-fos、c-myc mRNA表达的影响,初步探讨艾灸对RA滑膜细胞内分子信号传导的调控.方法在日本大耳白兔右后足踝关节部皮内注射福氏完全佐剂造模,经过艾灸治疗,通过半定量RT-PCR测定c-fos和c-myc mRNA的表达量.结果治疗组c-fos和c-myc mRNA表达量显著低于造模组(P<0.01).结论艾灸治疗能够降低c-fos和c-myc mRNA的表达,影响生长因子信号传导系统.

  4. Nodal diffuse large B-cell lymphomas in children and adolescents: immunohistochemical expression patterns and c-MYC translocation in relation to clinical outcome.

    Science.gov (United States)

    Gualco, Gabriela; Weiss, Lawrence M; Harrington, William J; Bacchi, Carlos E

    2009-12-01

    Diffuse large B-cell lymphoma (DLBCL) is a very infrequent neoplasm in the pediatric age group; therefore there are very few studies on the immunophenotype or genetics of these cases. We studied a series of 16 patients with nodal DLBCL occurring in patients between 10 and 18 years of age. The cases were classified according to the 2008 World Health Organization classification criteria, with application of immunohistochemistry for the detection of CD10, BCL-6, and MUM1 proteins to divide the lymphomas into germinal center and nongerminal center types. In addition, TCL1, BCL-2 expression, and the Ki-67 proliferation index were evaluated by immunohistochemistry, and c-MYC and BCL2 translocations were evaluated by fluorescence in situ hybridization. All these parameters were correlated with clinical features and outcome. Our study revealed that centroblastic morphology and the germinal center type of DLBCL are more prevalent in these young patients (63%), with 37% containing a c-MYC translocation. Only 1 case showed a BCL2 translocation, reflecting a double-hit case with features intermediate between DLBCL and Burkitt lymphoma. We found a higher frequency of BCL-2 expression than previously reported, with no direct influence on the outcome of the disease in univariate or multivariate analysis. The expression of TCL1 has not been specifically studied in nodal pediatric DLBCL before; we found a 31% incidence of TCL1 expression. MUM1 expression was observed in 44% of the cases and these positive cases showed a significant negative impact on clinical outcome. TCL1 is directly and significantly associated with the presence of c-MYC and a high proliferative index. The germinal center and nongerminal center subtypes showed significant differences for both overall survival and disease-free interval. c-MYC translocation was found in 37% of patients, and had a favorable impact on clinical outcome. We conclude that nodal pediatric and adolescent DLBCL are mainly of the germinal

  5. Physiological Expression and Accumulation of the Products of Two Upstream Open Reading Frames mrtl and MycHex1 Along With p64 and p67 Myc From the Human c-myc Locus.

    Science.gov (United States)

    Ji, Mi Hong; Kim, Seung-Ki; Kim, Chae-Yong; Phi, Ji Hoon; Jun, Hyun Jin; Blume, Scott W; Choi, Hyoung Soo

    2016-06-01

    In addition to the canonical c-Myc p64 and p67 proteins, the human c-myc locus encodes two distinct proteins, mrtl (myc-related translation/localization regulatory factor) and MycHex1 (Myc Human Exon 1), from the upstream open reading frames within the 5'-untranslated region of the c-myc P0 mRNA. The aim of this study is to examine simultaneously, for the first time, mrtl, MycHex1, c-Myc p64, and p67 in human tumor cell lines and pediatric brain tumor tissues. Western blot analysis demonstrated endogenous mrtl, MycHex1, c-Myc p64, and p67 simultaneously. The relative abundance of mrtl and MycHex1 were consistent among a variety of human tumor cell lines, and the relative intensities of mrtl and MycHex1 correlated positively. Confocal imaging revealed mrtl predominantly localized to the nuclear envelope, along with prominent reticular pattern in the cytoplasm. MycHex1 was observed as a series of bright foci located within the nucleus, a subset of which colocalized with fibrillarin. mrtl and MycHex1 co-immunoprecipitated with RACK1, c-Myc, fibrillarin, coilin, and with each other. These findings suggest that mrtl and MycHex1 have multiple interaction partners in both the nucleus and cytoplasm. Sequence analyses confirmed a known polymorphism of mrtl at base 1965 (G>T) and new mutations at bases 1900 (C>G) and 1798 (C>G). Evidence is presented for expression and stable accumulation of all four proteins encoded by three distinct non-overlapping open reading frames within the human c-myc locus. Additional work is warranted to further elucidate the functional or regulatory roles of these molecules in regulation of c-Myc and in oncogenesis.

  6. C-Myc induced compensated cardiac hypertrophy increases free fatty acid utilization for the citric acid cycle.

    Science.gov (United States)

    Olson, Aaron K; Ledee, Dolena; Iwamoto, Kate; Kajimoto, Masaki; O'Kelly Priddy, Colleen; Isern, Nancy; Portman, Michael A

    2013-02-01

    The protooncogene C-Myc (Myc) regulates cardiac hypertrophy. Myc promotes compensated cardiac function, suggesting that the operative mechanisms differ from those leading to heart failure. Myc regulation of substrate metabolism is a reasonable target, as Myc alters metabolism in other tissues. We hypothesize that Myc induced shifts in substrate utilization signal and promote compensated hypertrophy. We used cardiac specific Myc-inducible C57/BL6 male mice between 4-6 months old that develop hypertrophy with tamoxifen (tam) injections. Isolated working hearts and (13)Carbon ((13)C)-NMR were used to measure function and fractional contributions (Fc) to the citric acid cycle by using perfusate containing (13)C-labeled free fatty acids, acetoacetate, lactate, unlabeled glucose and insulin. Studies were performed at pre-hypertrophy (3-days tam, 3dMyc), established hypertrophy (7-days tam, 7dMyc) or vehicle control (Cont). Non-transgenic siblings (NTG) received 7-days tam or vehicle to assess drug effect. Hypertrophy was assessed by echocardiograms and heart weights. Western blots were performed on key metabolic enzymes. Hypertrophy occurred in 7dMyc only. Cardiac function did not differ between groups. Tam alone did not affect substrate contributions in NTG. Substrate utilization was not significantly altered in 3dMyc versus Cont. The free fatty acid FC was significantly greater in 7dMyc versus Cont with decreased unlabeled Fc, which is predominately exogenous glucose. Free fatty acid flux to the citric acid cycle increased while lactate flux was diminished in 7dMyc compared to Cont. Total protein levels of a panel of key metabolic enzymes were unchanged; however total protein O-GlcNAcylation was increased in 7dMyc. Substrate utilization changes for the citric acid cycle did not precede hypertrophy; therefore they are not the primary signal for cardiac growth in this model. Free fatty acid utilization and oxidation increase at established hypertrophy. Understanding the

  7. C-Myc Induced Compensated Cardiac Hypertrophy Increases Free Fatty Acid Utilization for the Citric Acid Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Olson, Aaron; Ledee, Dolena; Iwamoto, Kate; Kajimoto, Masaki; O' Kelly-Priddy, Colleen M.; Isern, Nancy G.; Portman, Michael A.

    2013-02-01

    The protooncogene C-Myc (Myc) regulates cardiac hypertrophy. Myc promotes compensated cardiac function, suggesting that the operative mechanisms differ from those leading to heart failure. Myc regulation of substrate metabolism is a reasonable target, as Myc alters metabolism in other tissues. We hypothesize that Myc-induced shifts in substrate utilization signal and promote compensated hypertrophy. We used cardiac specific Myc-inducible C57/BL6 male mice between 4-6 months old that develop hypertrophy with tamoxifen (tam). Isolated working hearts and 13Carbon (13C )-NMR were used to measure function and fractional contributions (Fc) to the citric acid cycle by using perfusate containing 13C-labeled free fatty acids, acetoacetate, lactate, unlabeled glucose and insulin. Studies were performed at pre-hypertrophy (3-days tam, 3dMyc), established hypertrophy (7-days tam, 7dMyc) or vehicle control (cont). Non-transgenic siblings (NTG) received 7-days tam or vehicle to assess drug effect. Hypertrophy was confirmed by echocardiograms and heart weights. Western blots were performed on key metabolic enzymes. Hypertrophy occurred in 7dMyc only. Cardiac function did not differ between groups. Tam alone did not affect substrate contribution in NTG. Substrate utilization was not significantly altered in 3dMyc versus cont. The free fatty acid FC was significantly greater in 7dMyc vs cont with decreased unlabeled Fc, which is predominately exogenous glucose. Free fatty acid flux to the citric acid cycle increased while lactate flux was diminished in 7dMyc compared to cont. Total protein levels of a panel of key metabolic enzymes were unchanged; however total protein O-GlcNAcylation was increased in 7dMyc. Substrate utilization changes did not precede hypertrophy; therefore they are not the primary signal for cardiac growth in this model. Free fatty acid utilization and oxidation increase at established hypertrophy. Understanding the mechanisms whereby this change maintained

  8. 流体切应力对脑动静脉畸形内皮细胞增殖与c-myc表达的影响%Effect of flow shear stress on endothelial cell proliferation and c-myc expression in cerebral arteriovenous malformation

    Institute of Scientific and Technical Information of China (English)

    赵明光; 李彦兵; 吕博川; 梁勇; 薛洪利; 赵丽萍; 王丹玲

    2007-01-01

    BACKGROUND:Shear stress can directly mediate the expression of endothelial cells, especially some cytokine genes whose codes are related to angiogenesis. Otherwise, flow shear stress of blood plays an importantly biological role in regulating vascular structure and function.OBJECTIVE: To observe the effects of laminar flow shear stress on the proliferation of vascular endothelial cells and the expression of protooncogene c-myc in human cerebral arteriovenous malformation.DESIGN: Randomized controlled study.SETTING: Department of Neurosurgery, Shenyang General Hospital of Military Area Command of Chinese PLA.MATERIALS: The experiment was carried out in the Neuromedical Institute, General Hospital of Shenyang Military Area Command of Chinese PLA from November 2006 to February 2007. Fresh samples of human cerebral arteriovenous malformation were derived from 20 patients who were of grade Spetzler Ⅱ -Ⅲ and received resection of human cerebral arteriovenous malformation in the Department of Neurosurgery, General Hospital of Shenyang Military Area Command of Chinese PLA in 2006. All cases were diagnosed with whole-brain angiography before operation. The main reagents and equipments were detailed as follows: M199 culture media (Gilbco BRL), quality fetal bovine serum (HyClone), endothelial cell growth supplement (ECGS; Sigma, USA), CO2 incubator (Forma Scientific, USA), flow cytometry analysis of cell cycle kit (BD Company), flow cytometer (FACS Calibur, BD Company), rat-anti-human c-myc monoclonal antibody (Santa Cruz Company, USA), and reverse transcription polymerase chain reaction (RT-PCR) kit (Promega).METHODS: Tissue explants adherent method was used to culture vascular endothelial cells of human cerebral arteriovenous malformation, and then the cells were classified into 4 groups based on degree of shear stress, including control group, low shear stress group, moderate shear stress group and high shear stress group. Cultured endothelial cells of human cerebral

  9. In vivo study on the effects of microcystin extracts on the expression profiles of proto-oncogenes (c-fos, c-jun and c-myc) in liver, kidney and testis of male Wistar rats injected i.v. with toxins.

    Science.gov (United States)

    Li, Huiying; Xie, Ping; Li, Guangyu; Hao, Le; Xiong, Qian

    2009-01-01

    Microcystins (MCs) are a potent liver tumor promoter, possessing potent tumor-promoting activity and weak initiating activity. Proto-oncogenes are known to be involved in the tumor-promoting mechanisms of microcystin-LR. However, few data are available on the effects of MCs on proto-oncogenes in the whole animal. To investigate the effects of MCs on the expression profile of the proto-oncogenes in different organs, male Wistar rats were injected intravenously with microcystin extracts at a dose of 86.7 mug MC-LR eq/kg bw (MC-LR eq, MC-LR equivalents). mRNA levels of three proto-oncogenes c-fos, c-jun and c-myc in liver, kidney and testis were analyzed using quantitative real-time PCR at several time points post-injection. Significant induction of these genes at transcriptional level was observed in the three organs. In addition, the increase of mRNA expression of all three genes was much higher in liver than in kidney and testis. Meanwhile, the protein levels of c-Fos and c-Jun were investigated by western blotting. Both proteins were induced in the three organs. However, elevations of protein levels were much lower than those of mRNA levels. These findings suggest that the expression of c-fos, c-jun and c-myc might be one possible mechanism for the tumor-promoting activity and initiating activity of microcystins.

  10. Surface-enhanced raman scattering surface selection rules for the proteomic liquid biopsy in real samples: Efficient detection of the oncoprotein c-MYC

    OpenAIRE

    2016-01-01

    NOTICE: This is the peer reviewed version of the following article: Elena Pazos, Manuel García-Algar, Cristina Penas, Moritz Nazarenus, Arnau Torruella, Nicolas Pazos-Perez, Luca Guerrini, M. Eugenio Vázquez, Eduardo Garcia-Rio*, José L. Macareñas* and Ramon A. Alvarez-Puebla* (2016), SERS Surface Selection Rules for the Proteomic Liquid Biopsy in Real Samples: Efficient Detection of the Oncoprotein c-MYC. J. Am. Chem. Soc., 138, 14206-14209 [DOI:10.1021/jacs.6b08957]. This article may be use...

  11. 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.

  12. The Role of c-Myc and miRNAs on EMT and the TGF-betaSwitch in Primary Intermediate Basal Cells Isolated From Prostate Cancer

    Science.gov (United States)

    2013-03-01

    embryos by retroviral vectors. Proc Natl Acad Sci U S A 86, 2224-2228. For Peer Review c-myc expression and MEK1 induced Erk2...cells using the pBABE-puro retroviral vector (a kind gift from Dr. Christian Sell, Drexel University College of Medicine). MEK1-DD and MEK2-DD were also...retroviral vector (a kind gift from Dr. Christian Sell, Drexel University College of Medicine). MEK1-DD and MEK2-DD were also over-expressed in cells

  13. The antihistamines clemastine and desloratadine inhibit STAT3 and c-Myc activities and induce apoptosis in cutaneous T-cell lymphoma cell lines.

    Science.gov (United States)

    Döbbeling, Udo; Waeckerle-Men, Ying; Zabel, Franziska; Graf, Nicole; Kündig, Thomas M; Johansen, Pål

    2013-02-01

    Mycosis fungoides and its leukaemic counterpart Sézary syndrome are the most frequent cutaneous T-cell lymphomas (CTCL), and there is no cure for these diseases. We evaluated the effect of clinically approved antihistamines on the growth of CTCL cell lines. CTCL cell lines as well as blood lymphocytes from patients with Sézary syndrome were cultured with antihistamines, and the cell were analysed for proliferation, apoptosis and expression of programmed death molecules and transcription factors. The two antihistamines clemastine and desloratadine, currently used for symptom alleviation in allergy, induced potent reduction of the activities of the constitutively active transcription factors c-Myc, STAT3, STAT5a and STAT5b in mycosis fungoides and Sézary syndrome cell lines. This inhibition was followed by apoptosis and cell death, especially in the Sézary syndrome-derived cell line Hut78 that also showed increased expression of the programmed death-1 (PD-1) after clemastine treatment. In lymphocytes isolated from Sézary syndrome patients, the CD4-positive fraction underwent apoptosis after clemastine treatment, while CD4-negative lymphocytes were little affected. Because both c-Myc and STAT transcription factors are highly expressed in proliferating tumours, their inhibition by clemastine, desloratadine and other inhibitors could complement established chemotherapies not only for cutaneous T-cell lymphomas but perhaps also other cancers.

  14. Phospholipase D1 Couples CD4+ T Cell Activation to c-Myc-Dependent Deoxyribonucleotide Pool Expansion and HIV-1 Replication.

    Directory of Open Access Journals (Sweden)

    Harry E Taylor

    2015-05-01

    Full Text Available Quiescent CD4+ T cells restrict human immunodeficiency virus type 1 (HIV-1 infection at early steps of virus replication. Low levels of both deoxyribonucleotide triphosphates (dNTPs and the biosynthetic enzymes required for their de novo synthesis provide one barrier to infection. CD4+ T cell activation induces metabolic reprogramming that reverses this block and facilitates HIV-1 replication. Here, we show that phospholipase D1 (PLD1 links T cell activation signals to increased HIV-1 permissivity by triggering a c-Myc-dependent transcriptional program that coordinates glucose uptake and nucleotide biosynthesis. Decreasing PLD1 activity pharmacologically or by RNA interference diminished c-Myc-dependent expression during T cell activation at the RNA and protein levels. PLD1 inhibition of HIV-1 infection was partially rescued by adding exogenous deoxyribonucleosides that bypass the need for de novo dNTP synthesis. Moreover, the data indicate that low dNTP levels that impact HIV-1 restriction involve decreased synthesis, and not only increased catabolism of these nucleotides. These findings uncover a unique mechanism of action for PLD1 inhibitors and support their further development as part of a therapeutic combination for HIV-1 and other viral infections dependent on host nucleotide biosynthesis.

  15. 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.

  16. NFATC1 promotes cell growth and tumorigenesis in ovarian cancer up-regulating c-Myc through ERK1/2/p38 MAPK signal pathway.

    Science.gov (United States)

    Xu, Wenwen; Gu, Junjie; Ren, Qingling; Shi, Yanqiu; Xia, Qinhua; Wang, Jing; Wang, Suli; Wang, Yingchun; Wang, Jinhua

    2016-04-01

    It has been reported that nuclear factor of activated T cells (NFATC1) was up-regulated in cancers mediating malignant behaviors. However, the role of NFATC1 in ovarian cancer has not been elucidated. In the present study, we undertook to explore the clinicopathological significance of NFATC1 expression and the mechanism by which NFATC1 works in ovarian cancer. Expression status of NFATC1 was examined using immunohistochemistry. Both knockdown and re-expression of NFATC1 on ovarian cancer cells were employed to observe the effect overgrowth. It was found that NFATC1 was significantly overexpressed in ovarian cancer tissues in comparison with paired normal control tissues and that overexpression of NFATC1 was significantly associated with metastasis and poor prognosis on clinical tissue level. In in vitro ovarian cancer cell lines, we found that NFATC1 can promote proliferation up-regulating c-myc through activation of ERK1/2/p38/MAPK signal pathway. Together, the results we obtained demonstrated that NFATC1 played oncogenic role in ovarian cancer. Mechanistically, NFATC1 promoted growth of ovarian cancer cells up-regulating c-myc through activation of ERK1/2/p38/MAPK signal pathway, suggesting that NFATC1 might be used as a therapeutic target for ovarian cancer.

  17. Complex Biological Systems Analysis of Cell Cycling Models in Carcinogenesis: I. The essential roles of modifications in the c-Myc, TP53/p53, p27 and hTERT modules in Cancer Initiation and Progression

    CERN Document Server

    Prisecaru, V I

    2004-01-01

    A new approach to the integration of results from a modular, complex biological systems analysis of nonlinear dynamics in cell cycling network transformations that are leading to carcinogenesis is proposed. Carcinogenesis is a complex process that involves dynamically inter-connected biomolecules in the intercellular, membrane, cytosolic, nuclear and nucleolar compartments that form numerous inter-related pathways referred to as networks. One such network module contains the cell cyclins whose functions are essential to cell cycling and division. Cyclins are proteins that also link to several critical pro-apoptotic and other cell cycling/division components, such as: c-Myc, p27, the tumor suppressor gene TP53 and its product-- the p53 protein with key roles in controlling DNA repair, inducing apoptosis and activating p21 (which can depress cell cyclins if activated), mdm2(with its biosynthesis activated by p53 and also, in its turn, inhibiting p53), p21, the Thomsen-Friedenreich antigen(T- antigen),Rb,Bax, Ba...

  18. Using myc genes to search for stem cells in the ciliary margin of the Xenopus retina.

    Science.gov (United States)

    Xue, Xiao Yan; Harris, William A

    2012-04-01

    The ciliary marginal zone (CMZ) of fish and frog retinas contains cells that proliferate throughout postembryonic development as the retina grows with increasing body size, indicating the presence of stem cells in this region. However, neither the location nor the molecular identity of retinal stem cells has been identified. Here, we show in Xenopus that c-myc and n-myc are sequentially expressed both during development and in the post-embryonic retina. The c-myc+/n-myc- cells near the extreme periphery of the CMZ cycle more slowly and preferentially retain DNA label compared to their more central cmyc+/n-myc+ neighbors which cycle rapidly and preferentially dilute DNA label. During retinal development c-myc is functionally required earlier than n-myc, and n-myc expression depends on earlier c-myc expression. The expression of c-myc but not n-myc in the CMZ depends on growth factor signaling. Our results suggest that c-myc+/n-myc- cells in the far peripheral CMZ are candidates for a niche-dependent population of retinal stem cells that give rise to more centrally located and rapidly dividing n-myc+ progenitors of more limited proliferative potential. Analysis of homologues of these genes in the zebrafish CMZ suggests that the transition from c-myc to n-myc expression might be conserved in other lower vertebrates whose retinas growth throughout life.

  19. c-Myc dependent expression of pro-apoptotic Bim renders HER2-overexpressing breast cancer cells dependent on anti-apoptotic Mcl-1

    Directory of Open Access Journals (Sweden)

    Jézéquel Pascal

    2011-09-01

    Full Text Available Abstract Background Anti-apoptotic signals induced downstream of HER2 are known to contribute to the resistance to current treatments of breast cancer cells that overexpress this member of the EGFR family. Whether or not some of these signals are also involved in tumor maintenance by counteracting constitutive death signals is much less understood. To address this, we investigated what role anti- and pro-apoptotic Bcl-2 family members, key regulators of cancer cell survival, might play in the viability of HER2 overexpressing breast cancer cells. Methods We used cell lines as an in vitro model of HER2-overexpressing cells in order to evaluate how anti-apoptotic Bcl-2, Bcl-xL and Mcl-1, and pro-apoptotic Puma and Bim impact on their survival, and to investigate how the constitutive expression of these proteins is regulated. Expression of the proteins of interest was confirmed using lysates from HER2-overexpressing tumors and through analysis of publicly available RNA expression data. Results We show that the depletion of Mcl-1 is sufficient to induce apoptosis in HER2-overexpressing breast cancer cells. This Mcl-1 dependence is due to Bim expression and it directly results from oncogenic signaling, as depletion of the oncoprotein c-Myc, which occupies regions of the Bim promoter as evaluated in ChIP assays, decreases Bim levels and mitigates Mcl-1 dependence. Consistently, a reduction of c-Myc expression by inhibition of mTORC1 activity abrogates occupancy of the Bim promoter by c-Myc, decreases Bim expression and promotes tolerance to Mcl-1 depletion. Western blot analysis confirms that naïve HER2-overexpressing tumors constitutively express detectable levels of Mcl-1 and Bim, while expression data hint on enrichment for Mcl-1 transcripts in these tumors. Conclusions This work establishes that, in HER2-overexpressing tumors, it is necessary, and maybe sufficient, to therapeutically impact on the Mcl-1/Bim balance for efficient induction of

  20. Genetic dissimilarity between primary colorectal carcinomas and their lymph node metastases: ploidy, p53, bcl-2, and c-myc expression--a pilot study.

    Science.gov (United States)

    Zalata, Khaled Refaat; Elshal, Mohamed Farouk; Foda, Abd AlRahman Mohammad; Shoma, Ashraf

    2015-08-01

    The current paradigm of metastasis proposes that rare cells within primary tumors acquire metastatic capability via sequential mutations, suggesting that metastases are genetically dissimilar from their primary tumors. This study investigated the changes in the level of expression of a well-defined panel of cell proliferation, differentiation, and apoptosis markers between the primary colorectal cancer (CRC) and the corresponding synchronous lymph node (LN) metastasis from the same patients. DNA flow cytometry and immunostaining of p53, bcl-2, and c-myc were carried out on 36 cases of CRC radical resection specimens with their corresponding LN metastases. There was very low probability that the histological patterns of primary tumors and LN metastases are independent (p < 0.001). Metastatic tumors were significantly more diffusely positive for p53 than the primary tumors (p < 0.001). Conversely, primary tumors were significantly more diffusely positive for c-myc than metastatic tumors (p = 0.011). No significant difference was found between the LNs and the primary tumors in bcl-2 positivity (p = 0.538) and DNA aneuploidy (p = 0.35), with a tendency towards negative bcl-2 and less aneuploidy in LN metastases than primary tumors. In conclusion, LN metastatic colorectal carcinomas have a tendency of being less differentiated, with a higher incidence of diffuse p53 staining, lower incidence of bcl-2 staining, and less aneuploidy in comparison to their primary counterparts suggesting a more aggressive biological behavior, which could indicate the necessity for more aggressive adjuvant therapy.

  1. PET/CT imaging of c-Myc transgenic mice identifies the genotoxic N-nitroso-diethylamine as carcinogen in a short-term cancer bioassay.

    Directory of Open Access Journals (Sweden)

    Katja Hueper

    Full Text Available BACKGROUND: More than 100,000 chemicals are in use but have not been tested for their safety. To overcome limitations in the cancer bioassay several alternative testing strategies are explored. The inability to monitor non-invasively onset and progression of disease limits, however, the value of current testing strategies. Here, we report the application of in vivo imaging to a c-Myc transgenic mouse model of liver cancer for the development of a short-term cancer bioassay. METHODOLOGY/PRINCIPAL FINDINGS: μCT and ¹⁸F-FDG μPET were used to detect and quantify tumor lesions after treatment with the genotoxic carcinogen NDEA, the tumor promoting agent BHT or the hepatotoxin paracetamol. Tumor growth was investigated between the ages of 4 to 8.5 months and contrast-enhanced μCT imaging detected liver lesions as well as metastatic spread with high sensitivity and accuracy as confirmed by histopathology. Significant differences in the onset of tumor growth, tumor load and glucose metabolism were observed when the NDEA treatment group was compared with any of the other treatment groups. NDEA treatment of c-Myc transgenic mice significantly accelerated tumor growth and caused metastatic spread of HCC in to lung but this treatment also induced primary lung cancer growth. In contrast, BHT and paracetamol did not promote hepatocarcinogenesis. CONCLUSIONS/SIGNIFICANCE: The present study evidences the accuracy of in vivo imaging in defining tumor growth, tumor load, lesion number and metastatic spread. Consequently, the application of in vivo imaging techniques to transgenic animal models may possibly enable short-term cancer bioassays to significantly improve hazard identification and follow-up examinations of different organs by non-invasive methods.

  2. c-Myc modulates glucose metabolism via regulation of miR-184/PKM2 pathway in clear-cell renal cell carcinoma.

    Science.gov (United States)

    Huang, Jiwei; Kong, Wen; Zhang, Jin; Chen, Yonghui; Xue, Wei; Liu, Dongming; Huang, Yiran

    2016-10-01

    Renal cell carcinoma (RCC) is one of the most malignant tumors worldwide. Among all subtypes of RCC, clear-cell RCC (ccRCC) is the most common and aggressive one. The difficulty in overcoming resistance of traditional treatment is a threat for ccRCC therapies. Therefore, to understand the mechanism that underlies ccRCC progression is critical for new drug development. In the present study, we identified that miR-184 could be downregulated by c-Myc, which is different from the standard opinion that c-Myc is a target of miR-184. Overexpression of pre-miR-184 changed the metabolic and proliferation features of ccRCC cells by reducing cell glucose consumption, lactate production and cell proliferation. Further analysis by computer bioinformatics revealed that PKM2 is a target of miR-184. Both PKM2 mRNA and protein were significantly affected by addition of miR-184. Importantly, the PKM2 expression level was indeed increased in ccRCC samples, which is totally reverse compared to the decreased miR-184 expression level. Interestingly, we found that when PKM2 was knocked down in ccRCC cells, the rapid proliferation, high glucose consumption and high lactate production were all clearly inhibited, which indicates metabolic reprogramming and cancer progression blocking the in ccRCC cells. Our findings shed new light on ccRCC molecular study and provide a new and solid basis for developing ccRCC therapy.

  3. Oridonin induces apoptosis and senescence in colorectal cancer cells by increasing histone hyperacetylation and regulation of p16, p21, p27 and c-myc

    Directory of Open Access Journals (Sweden)

    Zhao Ying-Zheng

    2010-11-01

    Full Text Available Abstract Background Oridonin, a tetracycline diterpenoid compound, has the potential antitumor activities. Here, we evaluate the antitumor activity and action mechanisms of oridonin in colorectal cancer. Methods Effects of oridonin on cell proliferation were determined by using a CCK-8 Kit. Cell cycle distribution was determined by flow cytometry. Apoptosis was examined by analyzing subdiploid population and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay. Senescent cells were determined by senescence-associated β-galactosidase activity analysis. Semi-quantitative RT-PCR was used to examine the changes of mRNA of p16, p21, p27 and c-myc. The concomitant changes of protein expression were analyzed with Western blot. Expression of AcH3 and AcH4 were examined by immunofluorescence staining and Western blots. Effects of oridonin on colony formation of SW1116 were examined by Soft Agar assay. The in vivo efficacy of oridonin was detected using a xenograft colorectal cancer model in nude mice. Results Oridonin induced potent growth inhibition, cell cycle arrest, apoptosis, senescence and colony-forming inhibition in three colorectal cancer cell lines in a dose-dependent manner in vitro. Daily i.p. injection of oridonin (6.25, 12.5 or 25 mg/kg for 28 days significantly inhibited the growth of SW1116 s.c. xenografts in BABL/C nude mice. With western blot and reverse transcription-PCR, we further showed that the antitumor activities of oridonin correlated with induction of histone (H3 and H4 hyperacetylation, activation of p21, p27 and p16, and suppression of c-myc expression. Conclusion Oridonin possesses potent in vitro and in vivo anti-colorectal cancer activities that correlated with induction of histone hyperacetylation and regulation of pathways critical for maintaining growth inhibition and cell cycle arrest. Therefore, oridonin may represent a novel therapeutic option in colorectal cancer treatment.

  4. Microwave-assisted synthesis of cupric (Ⅱ) complex with porphyrin and its interaction with c-myc G4 DNA%微波辅助四(P-甲氧苯基)卟啉铜(Ⅱ)的合成及其与c-myc G4 DNA的相互作用

    Institute of Scientific and Technical Information of China (English)

    孙福强; 梅文杰; 吴韦黎; 吴剑; 张召; 张紫伊; 崔英德

    2014-01-01

    以吡咯、p-甲氧基苯甲醛为原料,丙酸为溶剂,130℃条件下制得四(p-甲氧苯基)卟啉(TMOPP);然后在100℃微波辐射条件下,以TMOPP和乙酸铜为原料,DMF为溶剂,制得目标化合物四(p-甲氧苯基)卟啉铜(Ⅱ)配合物(CuTMOPP).采用电喷雾质谱、紫外光谱和红外光谱等分析方法对所合成的目标化合物进行了表征,目标化合物的理论值和实验值基本一致.进一步采用紫外光谱、CD光谱、FRET熔点实验、PCR-Stop实验考察了目标化合物与c-myc G4 DNA的相互作用,结果表明目标化合物可能与c-myc G4 DNA以静电方式结合,从而抑制其复制,进一步对其生物功能的影响还在研究中.

  5. 1,3-丁二烯作业工人遗传损伤与细胞周期蛋白D1基因多态性的关系%Association between CCND1 polymorphisms and chromosomal damage among workers exposed to 1,3-butadiene

    Institute of Scientific and Technical Information of China (English)

    刘楠; 李斌; 程娟; 郑国颖; 李云; 关维俊

    2015-01-01

    目的 探讨1,3-丁二烯(BD)作业工人外周血淋巴细胞遗传物质损伤状况及其与细胞周期蛋白D1(CCND1)基因多态性的关系.方法 采用外周血淋巴细胞胞质分裂阻滞微核(CBMN)试验和彗星试验评价171名BD作业工人和55名非职业暴露对照人群的染色体和DNA损伤水平,应用聚合酶链反应-限制性片段长度多态性方法分析CCND1基因的多态性.同时,通过问卷调查的方式了解被调查者的年龄、性别、吸烟、饮酒和个人职业暴露史.结果 BD作业工人外周血淋巴细胞微核率和彗星尾距分别为(7.17±5.09)‰和4.65(95%CI 3.49~5.98),均高于对照组(3.82±2.37)‰和2.38(95% CI0.82~3.98),差异有统计学意义(P<0.01);暴露组中具有CCND1基因A870G位点GG基因型个体的彗星尾距显著低于AA基因型个体(P<0.05).结论 在现有BD暴露水平下,外周血淋巴细胞胞质分裂阻滞微核法和彗星试验均能检出BD作业工人的遗传物质损伤;CCND1等位基因A870G位点GG基因型可能与职业性BD暴露导致的外周血淋巴细胞DNA损伤水平增加风险相关联.

  6. Clinical significance of bcl-6, p53, c-myc aberrations in diffuse large B-cell lymphoma%bcl-6、p53、c-myc基因异常在弥漫大B细胞淋巴瘤中的临床意义

    Institute of Scientific and Technical Information of China (English)

    何兰兰; 严峰; 刘德亮; 曹祥山; 谢晓宝; 王志林

    2013-01-01

    Objective To investigate aberrations of bcl-6,p53,c-myc genes in diffuse large B-cell lymphoma (DLBCL) and its clinical significance.Methods Interphase fluorescence in situ hybridization (I-FISH) was detected in 59 DLBCL patients in vivo tissue bcl-6,p53 protein,c-myc gene status.The patients were treated with CHOP or R-CHOP chemotheralpy,and the survival rates and treatment efficiency were compared.Results The p53 deletion was detected in 18 of the 59 cases (30.5 %),bcl-6 rearrangement in 11 cases (18.6 %),5 cases with c-myc rearrangement (8.5 %).In the aspects of remission rate,p53 deletion positive group contained less advantage than negative ones (33.3 % vs 75.6 %,x2 =9.560,P =0.002).The prognosis of bcl-6 gene rearrangement positive group different from negative group,but the difference was not statistically significant (OS,P =0.107; PFS,P =0.094),p53 deletion positive patients was in significantly worse prognosis than the negative group (OS,P =0.031; PFS,P =0.028),c-myc rearrangement positive group difference in gene rearrangement negative group,but the difference was not statistically significant (OS,P =0.163; PFS,P =0.167).In the CHOP group,prognosis of p53 deletion,c-myc rearrangement positive group were significantly worse than the negative group,the difference was statistically significant (P < 0.05).In R-CHOP group,the prognostic significance of bcl-6 gene rearrangement positive group were worse (OS,P =0.003; PFS,P =0.007).Conclusion DLBCL patients with bcl-6,p53,c-myc genes aberrations are related with poor prognosis,and they can be used as prognostic factors for predicting DLBCL and guiding therapy.%目的 探讨bcl-6 、p53、c-myc基因异常的检测在弥漫大B细胞淋巴瘤(DLBCL)中的临床意义.方法 间期荧光原位杂交(I-FISH)方法检测59例DLBCL患者活体石蜡组织bcl-6、p53蛋白、c-myc基因异常的情况,同时以CHOP及R-CHOP方案化疗,评价疗效.观察bcl-6、p53蛋白、c-myc基因与化疗疗

  7. Expression and clinic significance of gene-associated lymphoma of salivary glands%涎腺非霍奇金淋巴瘤相关基因表达及意义

    Institute of Scientific and Technical Information of China (English)

    蔡杰; 张品南; 郭群

    2012-01-01

    Objective: To investigate clinicopathological and genetic characteristics of Lymphoma of salivary glands. Methods: Clinical, morphological and immunohistochemical feature of 32 cases of lymphoma in salivary glands were studied,including 5 cases of rective lymphoid hyperplasia and 32 lymphomas, retrospectivily. Classification of the lymphomas were made assording to the WHO classification of tumors of haemtopoietic and lymphoid tissues. All cases were studied with interphase fluorescence in situ hybridization (FISH) using dual color break apart probes of IgH, MALT1, bc1-6, c-myc, bc1-2, CCND1, bc1-10, and FOXP1 for detection of chromosomal aberrations, involving IgH, MALT1, bcl-6, c-myc, bcl-2, cyclinDl, bcl-10 and F0XP1 gene, repectively. FISH with IgH/bc1-2 dual fusion probe was used for detection of t (14 ; 18)(q32; q21)/IgH-bc1-2. CEP18 sepctrum orange probe was used for detection of aneuploidy of the chromosome 18. Results: Among 32 cases of lymphoma, 28 cases (87.5%) were extranodal marginal zone B-cell lymphoma of mucosa associated lymphoid tissue (MALT lymphoma), 2 cases were fol-licular lymphoma (FL) and 2 cases diffuse large B-cell lymphoma (DLBCL). Among the 28 cases of MALT lymphoma, chromosomal aberration were found in 60.7% (17/28) with interphase FISH analysis. One case showed positive IgH break-apart signal with unknown partner, 16 cases showed three copies of different genes, of which, three copies of MALT1, bcl-6, and c-myc were identified in 7 cases (25%), 12 cases (43%),and 2 cases (8%) of MALT lymphomas, respectively. In addition, 5 cases showed two genes, including three copies of bcl-6 and MALT1 in 4 cases, and three copies of bcl-6 together with c-myc in one case. Furthermore, all cases with three copies of MALT1 had trisomy 18(14; 18) (q32; q2l)was detected in both follicular lymphomas. Of the 2 DLBCL cases, one showed three copies of bc1-6 together with trisomy18 and the other one showed three copies of bcl-6 together with IgH and c-myc

  8. Thermo-Responsive Complexes of c-Myc Antisense Oligonucleotide with Block Copolymer of Poly(OEGMA) and Quaternized Poly(4-Vinylpyridine).

    Science.gov (United States)

    Topuzogullari, Murat; Elalmis, Yeliz Basaran; Isoglu, Sevil Dincer

    2017-04-01

    Solution behavior of thermo-responsive polymers and their complexes with biological macromolecules may be affected by environmental conditions, such as the concentration of macromolecular components, pH, ion concentration, etc. Therefore, a thermo-responsive polymer and its complexes should be characterized in detail to observe their responses against possible environments under physiological conditions before biological applications. To briefly indicate this important issue, thermo-responsive block copolymer of quaternized poly(4-vinylpyridine) and poly(oligoethyleneglycol methyl ether methacrylate) as a potential nonviral vector has been synthesized. Polyelectrolyte complexes of this copolymer with the antisense oligonucleotide of c-Myc oncogene are also thermo-responsive but, have lower LCST (lower critical solution temperature) values compared to individual copolymer. LCST values of complexes decrease with molar ratio of macromolecular components and presence of salt. Dilution of solutions also affects solution behavior of complexes and causes a significant decrease in size and an increase in LCST, which indicates possible effects of severe dilutions in the blood stream.

  9. Radiosensitivity of small-cell lung cancer xenografts compared with activity of c-myc, N-myc, L-myc, c-raf-1 and K-ras proto-oncogenes

    DEFF Research Database (Denmark)

    Rygaard, K; Slebos, R J; Spang-Thomsen, M

    1991-01-01

    , the CPH and the GLC series. CPH-54A and CPH-54B are in vitro-derived subclones of a SCLC cell line, while the GLC tumours were established as cell lines from a patient during longitudinal follow-up. Both tumours were later transferred into nude mice. CPH-54A was more sensitive to single-dose irradiation...... than CPH-54B, while, with respect to the 3 GLC tumours examined, GLC-16 was most sensitive, followed by GLC-14 and GLC-19. The CPH tumours expressed similar amounts of c-myc and c-raf-1 mRNA, and neither expressed N-myc or L-myc. GLC-14 expressed N-myc and c-raf-1 mRNA but no c-myc. GLC-16 and GLC-19...

  10. Stabilization of c-myc G-Quadruplex DNA, inhibition of telomerase activity, disruption of mitochondrial functions and tumor cell apoptosis by platinum(II) complex with 9-amino-oxoisoaporphine.

    Science.gov (United States)

    Qin, Jiao-Lan; Qin, Qi-Pin; Wei, Zu-Zhuang; Yu, Yan-Cheng; Meng, Ting; Wu, Chen-Xuan; Liang, Yue-Lan; Liang, Hong; Chen, Zhen-Feng

    2016-11-29

    [Pd(L)(DMSO)Cl2] (1) and [Pt(L)(DMSO)Cl2] (2) with 9-amino-oxoisoaporphine (L), were synthesized and characterized. 1 and 2 are more selectively cytotoxic to Hep-G2 cells versus normal liver cells (HL-7702). Various experiments showed that 2 acted as telomerase inhibitors targeting G4-DNA and triggered cell apoptosis by interacting with c-myc G4-DNA. Furthermore, 2 significantly induced cell cycle arrest at both G2/M and S phase, which leading to the down-regulation of cdc25 A, cyclin D, cyclin B, cyclin A and CDK2 and the up-regulation of p53, p27, p21,chk1 and chk2. In addition, 2 also caused mitochondrial dysfunction. Taken together, we found that 2 exerted its cytotoxic activity mainly via inhibiting telomerase by interaction with c-myc G4-DNA and disruption of mitochondrial function.

  11. Microwave-assisted synthesis of arene ruthenium(II) complexes [(η⁶-RC₆H₅)Ru(m-MOPIP)Cl]Cl (R = -H and -CH₃) as groove binder to c-myc G4 DNA.

    Science.gov (United States)

    Wu, Qiong; Chen, Tianfeng; Zhang, Zhao; Liao, Siyan; Wu, Xiaohui; Wu, Jian; Mei, Wenjie; Chen, Yanhua; Wu, Weili; Zeng, Lingli; Zheng, Wenjie

    2014-06-28

    Two arene Ru(II) complexes coordinated by 2-(3-methoxyphenyl)imidazole[4,5-f][1,10]phenanthroline, [(η(6)-RC6H5)Ru(m-MOPIP)Cl]Cl (R = H, ; R = CH3, 2), have been prepared under microwave irradiation; the crystal structure of 2 exhibits a typical "piano stool" conformation, with bond angles for N1-Ru1-Cl1 86.02 (14)° and N2-Ru1-Cl1 84.51 (14)°. The Ru-C distance for the Ru atom bound to the benzene ring is about 0.2178(8) nm, and the average Ru-N distance for Ru atom to the two chelating N atoms is about 0.2092(4) nm. The evaluation of in vitro anticancer activities revealed that these synthetic Ru(II) complexes selectively inhibited the growth of HepG2 hepatocellular carcinoma cells, with low cytotoxicity toward LO2 human normal liver cells. The results demonstrated that the complexes exhibited great selectivity between human cancer and normal cells by comparing with the ligand m-MOPIP. Furthermore, complexes 1 and 2 could bind to c-myc G4 DNA in groove binding mode in promising affinity, and the insertion of the methyl groups in the arene ligand contributed to strengthen the binding affinity. This was also confirmed by molecular docking calculation and (1)H NMR analysis which showed that both 1 and 2 can bind in the loop constructed by A6-G9 and G21-A25 base pairs in c-myc G4 DNA to block the replication of c-myc oligomer. Taken together, these results suggest that arene Ru(II) complexes display application potential as small molecule inhibitors of c-myc G4 DNA.

  12. Quercetin通过TGF-β1/smad3/c-myc信号通路对LOVO细胞增殖的抑制作用%Quercetin inhibits proliferation of LOVO cells through TGF-β1/smad3 / c-myc signaling pathway

    Institute of Scientific and Technical Information of China (English)

    安昌勇; 寇耀; 赵林; 邵新宏; 张刘平; 张才全

    2013-01-01

    Objective To investigate the effect of Quercetin on TlGF-βl/smad3/c-myc signating pamway of LO V O cell strain as well as the possible mechanisms of inhibitory effect of Quercetin on the proliferation of LOVO cells.Methods Lovo ceils were treated with Quercetin at dosages of 5,10,20,40,80 and 160 μmol / L for 48 h respectively,using those untreated as control,and determined for proliferation activity.LOVO cells were divided into C,T,TQ and Q groups.The cells in C group were untreated,while those in T group were treated with 5 ng/ml TGF-β1 for one week,those in TQ group with 5 ng/ml TGF-β1 for one week then with 20 μmol/L Quercetin for 72 h,and those in Q group with 20 μmol/L Quercetin for 72 h.The effects of Quercetin and TGF-β1 on the clone formation ability as well as expressions of smad3 and c-myc were analyzed by plate clone formation test,immunohistochemical assay with SP staining,RT-PCR and Western blot.Results Quercetin showed significantly dosage-dependent inhibitory effect on proliferation of LOVO cells,with an IC50 of about 40 μmol/L.The proliferation of LOVO cells as well as expressions of smad3 and c-myc were promoted by TGF-β1 significantly (P < O.05),while were inhibited by Quercetin significantly (P < 0.05).As compared with those in TQ group,both the proliferation ability and the expression level of c-myc in TQ group decreased significantly(P < 0.05).Conclusion Quercetin down-regulated the expression of target gene c-myc by inhibiting the TGF-β1/smad3/c-myc signaling pathway,and inhibited the proliferation of LOVO cells.%目的 研究Quercetin对结肠癌LOVO细胞株TGF-β1/smad3/c-myc信号通路的影响,并探讨其抑制LOVO细胞增殖的可能机制.方法 采用5、10、20、40、80、160 μmol/L的Quercetin处理结肠癌LOVO细胞48 h,以未经Quercetin处理的LOVO细胞作为对照组,采用MTT法检测Quercetin对细胞增殖活力的影响.以5 ng/ml的TGF-Bl刺激l周的LOVO细胞为细胞模型,设对照

  13. Rate of CRL4(CRBN) substrate Ikaros and Aiolos degradation underlies differential activity of lenalidomide and pomalidomide in multiple myeloma cells by regulation of c-Myc and IRF4.

    Science.gov (United States)

    Bjorklund, C C; Lu, L; Kang, J; Hagner, P R; Havens, C G; Amatangelo, M; Wang, M; Ren, Y; Couto, S; Breider, M; Ning, Y; Gandhi, A K; Daniel, T O; Chopra, R; Klippel, A; Thakurta, A G

    2015-10-02

    Recent discoveries suggest that the critical events leading to the anti-proliferative activity of the IMiD immunomodulatory agents lenalidomide and pomalidomide in multiple myeloma (MM) cells are initiated by Cereblon-dependent ubiquitination and proteasomal degradation of substrate proteins Ikaros (IKZF1) and Aiolos (IKZF3). By performing kinetic analyses, we found that the downregulation or proteasomal degradation of Ikaros and Aiolos led to specific and sequential downregulation of c-Myc followed by IRF4 and subsequent growth inhibition and apoptosis. Notably, to ensure growth inhibition and cell death, sustained downregulation of Ikaros and Aiolos, c-Myc or IRF4 expression was required. In addition, we found that the half-maximal rate, rather than the final extent of Ikaros and Aiolos degradation, correlated to the relative efficacy of growth inhibition by lenalidomide or pomalidomide. Finally, we observed that all four transcription factors were elevated in primary MM samples compared with normal plasma cells. Taken together, our results suggest a functional link between Ikaros and Aiolos, and the pathological dysregulation of c-Myc and IRF4, and provide a new mechanistic understanding of the relative efficacy of lenalidomide and pomalidomide based on the kinetics of substrate degradation and downregulation of their downstream targets.

  14. Rate of CRL4CRBN substrate Ikaros and Aiolos degradation underlies differential activity of lenalidomide and pomalidomide in multiple myeloma cells by regulation of c-Myc and IRF4

    Science.gov (United States)

    Bjorklund, C C; Lu, L; Kang, J; Hagner, P R; Havens, C G; Amatangelo, M; Wang, M; Ren, Y; Couto, S; Breider, M; Ning, Y; Gandhi, A K; Daniel, T O; Chopra, R; Klippel, A; Thakurta, A G

    2015-01-01

    Recent discoveries suggest that the critical events leading to the anti-proliferative activity of the IMiD immunomodulatory agents lenalidomide and pomalidomide in multiple myeloma (MM) cells are initiated by Cereblon-dependent ubiquitination and proteasomal degradation of substrate proteins Ikaros (IKZF1) and Aiolos (IKZF3). By performing kinetic analyses, we found that the downregulation or proteasomal degradation of Ikaros and Aiolos led to specific and sequential downregulation of c-Myc followed by IRF4 and subsequent growth inhibition and apoptosis. Notably, to ensure growth inhibition and cell death, sustained downregulation of Ikaros and Aiolos, c-Myc or IRF4 expression was required. In addition, we found that the half-maximal rate, rather than the final extent of Ikaros and Aiolos degradation, correlated to the relative efficacy of growth inhibition by lenalidomide or pomalidomide. Finally, we observed that all four transcription factors were elevated in primary MM samples compared with normal plasma cells. Taken together, our results suggest a functional link between Ikaros and Aiolos, and the pathological dysregulation of c-Myc and IRF4, and provide a new mechanistic understanding of the relative efficacy of lenalidomide and pomalidomide based on the kinetics of substrate degradation and downregulation of their downstream targets. PMID:26430725

  15. Altered expression of Bcl-2, c-Myc, H-Ras, K-Ras, and N-Ras does not influence the course of mycosis fungoides

    Science.gov (United States)

    Maj, Joanna; Jankowska-Konsur, Alina; Plomer-Niezgoda, Ewa; Sadakierska-Chudy, Anna

    2013-01-01

    Introduction Data about genetic alterations in mycosis fungoides (MF) are limited and their significance not fully elucidated. The aim of the study was to explore the expression of various oncogenes in MF and to assess their influence on the disease course. Material and methods Skin biopsies from 27 MF patients (14 with early MF and 13 with advanced disease) and 8 healthy volunteers were analyzed by real-time polymerase chain reaction (PCR) to detect Bcl-2, c-Myc, H-Ras, K-Ras and N-Ras expression. All PCR reactions were performed using an Applied Biosystems 7900HT Fast Real-Time PCR System and interpreted using Sequence Detection Systems software which utilizes the comparative delta Ct method. The level of mRNA was normalized to GAPDH expression. All data were analyzed statistically. Results All evaluated oncogenes were found to be expressed in the skin from healthy controls and MF patients. Bcl-2 (–4.2 ±2.2 vs. –2.2 ±1.1; p = 0.01), H-Ras (–3.0 ±3.3 vs. 0.6 ±2.6; p = 0.01) and N-Ras (–3.6 ±2.0 vs. –1.1 ±2.4; p = 0.03) were expressed at significantly lower levels in MF. No relationships between oncogene expression and disease stage, presence of distant metastases and survival were observed (p > 0.05 for all comparisons). Conclusions The pathogenic role and prognostic significance of analyzed oncogenes in MF seem to be limited and further studies are needed to establish better prognostic factors for patients suffering from MF. PMID:24273576

  16. GDNF Up-Regulates c-Myc Transcription via the PI3K/Akt Pathway to Promote Dairy Goat Male Germline Stem Cells (mGSC) Proliferation

    Institute of Scientific and Technical Information of China (English)

    SUN Jun-wei; ZHU Hai-jing; LIU Chao; LI Ming-zhao; HUA Jin-lian

    2013-01-01

    Studies have demonstrated that regulation of GDNF on male germline stem cells (mGSCs) mainly through Ras/Erk1/2, Src family kinase and PI3K/Akt signaling pathways, but the signaling pathways GDNF-mediated are different when the species and cell lines varied. Whether GDNF regulates self-renewal of mGSCs isolated from livestock has not been reported. Here, we purified mGSCs from dairy goat testis using mixed enzymes and fibronectin. Immunofluoresce staining revealed the cultured dairy mGSCs expressed Vasa, Nanos2, Ngn3, Tert, Dazl, Lin28, Oct4, CD49f, Stra8 and GFRa1, reflecting that these cells were mGSCs phenotype. Then we cultured these dairy goat mGSCs in different concentrations of GDNF (0, 5, 10, or 20 ng mL-1) to optimize the best concentration of GDNF to sustain the dairy goat mGSCs self-renewal, after that the inhibitor of PI3K (LY294002, 10μmol L-1) was added to the medium which contains the optimal concentration of GDNF we obtained by experiments. The mGSCs cultured in different media were compared through the population doubling time (PDT), capacity of cell proliferation evaluated by PCNA and BrdU immunofluorescence staining, RT-PCR, QRT-PCR, Western blotting and flow cytometry. Results showed that 10 ng mL-1 was the optimal concentration of GDNF to maintain goat mGSCs self-renewal and GDNF up-regulates c-Myc transcription via the PI3K/Akt pathway to promote goat mGSCs proliferation. This study provides us an efficient model to study the mechanism in mGSCs proliferation and differentiation in goat, and has important implications in unveiling signaling pathways in livestock GSCs.

  17. Pokemon mRNA在乳腺癌中的表达及与c- myc相关性分析%Expression of Pokemon mRNA in breast carcinoma and its relationship to c-myc

    Institute of Scientific and Technical Information of China (English)

    付朝江; 崔明; 徐衍; 王应霞

    2011-01-01

    目的:探讨人乳腺癌中原癌基因c-myc和Pokemon mRNA在乳腺癌组织中的表达及其与乳腺癌发生、转移的相关性.方法:收集浸润性导管癌组织、癌旁乳腺组织、正常乳腺组织各45、20和20例,用原位杂交法检测Pokemon mRNA表达,并用免疫组织化学法检测浸润性导管癌c-myc表达,并进行统计分析.结果:乳腺癌细胞质Pokemon mRNA的表达率为71.2%(37/45),显著高于癌旁正常乳腺组织40%(8/20)、乳腺增生组织25%(5/20), 三者有显著性差异 (P<0.05),细胞质c-myc阳性率分别为86.67%、60.0%、50.0%,三者有显著性差异(P<0.05).细胞质Pokemon mRNA表达与乳腺癌淋巴结转移、组织学分级相关(P<0.05).细胞质c-myc表达与乳腺癌腋窝淋巴结转移相关(P<0.05).45例乳腺癌细胞质Pokemon mRNA与c-myc表达呈正相关(γ=0.585 ,P<0.05).结论:Pokemon mRNA的表达可能在乳腺导管癌的组织发生中起关键作用,c-myc的过度表达可能与乳腺癌Pokemon基因转录激活有关.%Objective: To explore the expression and interaction of Pokemon mRNA and proto - oncogene c - myc in the course of carcinogenesis and metastasis of breast cancer.Methods : The expression of Pokemon mRNA was examined by in situhybridization in 45 cases of breast cancer,20 cases of adjacent noncancerous breast tissue and 20 cases of mammary gland hyperplasia,The expression of c - myc was examined by immunohistochemistry in 45 cases of carcinoma.Results:The rate of strong positive plasma Pokemon mRNA and c - myc expression was significandy higher in breast cancer than in adjacent noncancerous breast tissue and mammary gland hyperplasia ( P < 0.05 ) , the rates of strong positive plasma Pokemon expression were 71.2% ( 37/45 ) ,40% ( 8/20) , 25 % ( 5/20) ;86.67% 、60.0% 、50.0% , respectively.The positive expreasion of Pokemon mRNA and c - myc in breast cancer was strongly related to lympb nodemetastasis(P <0.05) .The expre8aion of Pokemon m

  18. 人胎冠状动脉原位杂交c-myc和jun原癌基因表达%Expression of proto - oncogenes c - myc and jun in human coronary artery ruring development

    Institute of Scientific and Technical Information of China (English)

    蔡维君; 陈新平; 伍校琼; 罗学港

    2004-01-01

    目的研究原癌基因c-myc和jun在人胎冠状动脉发育过程中的表达与平滑肌细胞增殖的关系.方法用原位杂交方法检测,胎龄分别为16周、22周(因治疗需要引产)的胎儿和意外死亡的足月胎儿冠状动脉前降支c-myc mRNA和jun mRNA的表达水平.杂交反应产物用图像分析仪(MIAS300)作定量分析.结果C-myc mRNA原位杂交反应产物与被测血管区域面积的百分比在16周、22周和足月胎儿分别是70、56和10;Jun mRNA的杂交信反应产物与被测血管区域面积的百分比在这三个时期分别是68、53和8.两个原癌基因在不同阶段的表达均具有显著性差异.结论本实验首次报道c-myc和jun在人胎冠状动脉发育过程中平滑肌的表达图型,c-myc和jun在胎儿冠状动脉平滑肌细胞增殖和内膜的形成过程中可能具有重要的调控作用.%Objective: To investigate the expression of protooncogenes, c - myc and jun, in human coronary artery during development. Methods: In situ hybridization was employed to detect c - myc mRNA and jun mRNA in human coronary artery from aborted fetus with embryonic ages from week 16 to 22 due to treatment requirements. In addition, 3 cases of full term human fetus died of accident were also studied. Hybridized signals were quantified with a computer - assisted image - analyzing system ( MIAS 300 ). Results: The ratio of hybridized signal of c - myc to the area of vascular wall detected were 0.7, 0.54 and 0.10 respectively corresponding to the embryonic ages, 16 weeks,22 weeks and full term. Similar results with the ratio of 0.68, 0.53 and 0.08 for jun mRNA at above embryonic ages was also found. The levels of c - myc and jun mRNA expressed at different embryonic stage showed a significant difference. Conclusions: We first reported the expression of proto - oncogenes, c - myc and jun, in human coronary artery during embryonic development. These two proto - oncogenes may play an important role in the

  19. 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...

  20. An alternative pathway for gene regulation by Myc

    DEFF Research Database (Denmark)

    Peukert, K; Staller, P; Schneider, A

    1997-01-01

    The c-Myc protein activates transcription as part of a heteromeric complex with Max. However, Myc-transformed cells are characterized by loss of expression of several genes, suggesting that Myc may also repress gene expression. Two-hybrid cloning identifies a novel POZ domain Zn finger protein (Miz...

  1. Reevesioside A, a cardenolide glycoside, induces anticancer activity against human hormone-refractory prostate cancers through suppression of c-myc expression and induction of G1 arrest of the cell cycle.

    Directory of Open Access Journals (Sweden)

    Wohn-Jenn Leu

    Full Text Available In the past decade, there has been a profound increase in the number of studies revealing that cardenolide glycosides display inhibitory activity on the growth of human cancer cells. The use of potential cardenolide glycosides may be a worthwhile approach in anticancer research. Reevesioside A, a cardenolide glycoside isolated from the root of Reevesia formosana, displayed potent anti-proliferative activity against human hormone-refractory prostate cancers. A good correlation (r² = 0.98 between the expression of Na⁺/K⁺-ATPase α₃ subunit and anti-proliferative activity suggested the critical role of the α₃ subunit. Reevesioside A induced G1 arrest of the cell cycle and subsequent apoptosis in a thymidine block-mediated synchronization model. The data were supported by the down-regulation of several related cell cycle regulators, including cyclin D1, cyclin E and CDC25A. Reevesioside A also caused a profound decrease of RB phosphorylation, leading to an increased association between RB and E2F1 and the subsequent suppression of E2F1 activity. The protein and mRNA levels of c-myc, which can activate expression of many downstream cell cycle regulators, were dramatically inhibited by reevesioside A. Transient transfection of c-myc inhibited the down-regulation of both cyclin D1 and cyclin E protein expression to reevesioside A action, suggesting that c-myc functioned as an upstream regulator. Flow cytometric analysis of JC-1 staining demonstrated that reevesioside A also induced the significant loss of mitochondrial membrane potential. In summary, the data suggest that reevesioside A inhibits c-myc expression and down-regulates the expression of CDC25A, cyclin D1 and cyclin E, leading to a profound decrease of RB phosphorylation. G1 arrest is, therefore, induced through E2F1 suppression. Consequently, reevesioside A causes mitochondrial damage and an ultimate apoptosis in human hormone-refractory prostate cancer cells.

  2. Detection of Tumor Suppressor Gene and Oncogene in SO-Rb_(50) Human Retinoblastoma Cell Line

    Institute of Scientific and Technical Information of China (English)

    1993-01-01

    Retinoblastoma (Rb) is the most common malignant'cancer of eye. So-Rb_(50) is the first Rb cell line established in China in 1988. It has passed to the 387th passage now. We collected cells of the 327th passage of SO-Rb_(50), purified its genomic DNA and detected it with Rb and c-myc cDNA probes respectively (normal human white blood cells DNA was the control). We found the Rb gene was deleted while c-myc gene was amplified three times. This provides a basis for further study of the regulation of tumor ...

  3. Correlation of expression VEGF to expression of protooncogenes of c-fos and c-myc at protein level among various grades of liver cirrhosis%硬变肝组织VEGF的表达与原癌基因c-fos,c-myc 以及肝功能分级的相关性研究

    Institute of Scientific and Technical Information of China (English)

    施宝民; 杨镇; 张黎; 李大鹏

    2001-01-01

    目的探讨血管内皮生长因子(VEGF)在肝硬化发生发展中的作用以及肝脏原癌基因(c-fos,c-myc)与肝功能Child分级的相关关系。方法通过对54例硬变肝组织中的VEGF、c-fos、c-myc蛋白的免疫组化检测,观察VEGF的蛋白水平表达与肝脏功能Child 分级的相关性,同时分析VEGF阳性病例组与阴性病例组c-fos、c-myc的不同表达,来了解二者的相互作用关系。结果 Child A级与Child B级VEGF的表达显著高于Child C级和对照组(P<0.05),而Child A级与Child B级之间差异无显著性意义(P>0.05)。c-fos 及c-myc的表达在VEGF阳性组和阴性组差异无显著性意义(P>0.05)。结论 VEGF的水平可以反映肝脏功能的代偿状态,可能在肝硬化的进程中起着保肝作用;原癌基因c-fos、c-myc与VEGF作用在不同环节。

  4. TA1 oncofetal rat liver cDNA and putative amino acid permease: temporal correlation with c-myc during acute CCl4 liver injury and variation of RNA levels in response to amino acids in hepatocyte cultures.

    Science.gov (United States)

    Shultz, V D; Campbell, W; Karr, S; Hixson, D C; Thompson, N L

    1999-01-01

    TA1 is a rat liver oncofetal cDNA and a member of an emerging family of evolutionarily conserved molecules with homology to amino acid transporters and permeases. The aim of these studies was to characterize the regulation and role of TA1 in acute rat liver injury by examining its relation to regeneration and metabolic stress. Following a single dose of CCl4, TA1 message was expressed 3-48 h. The major 3.3-kb TA1 transcript correlated temporally with c-myc expression. A novel 2.9-kb TA1 transcript was expressed more variably 24-48 h. TA1 protein was restricted to hepatocytes in G0 and G1 phases of the cell cycle. Relative to CCl4, a much smaller increase in TA1 was noted after partial hepatectomy and TA1 preceded the peak of c-myc expression. In vitro TA1 was not induced in hepatocytes by EGF or the acute-phase cytokines IL-6 and TNF-alpha, but was found to be modulated in response to amino acid availability. TA1 expression increased in media without arginine and glutamine and was repressed by total amino acid levels 5-fold over basal MEM. Together, these results contrast with the constitutive expression observed in transformed cells and suggest an adaptive role for TA1 during liver injury.

  5. Differential regulation of LncRNA-SARCC suppresses VHL-mutant RCC cell proliferation yet promotes VHL-normal RCC cell proliferation via modulating androgen receptor/HIF-2α/C-MYC axis under hypoxia.

    Science.gov (United States)

    Zhai, W; Sun, Y; Jiang, M; Wang, M; Gasiewicz, T A; Zheng, J; Chang, C

    2016-09-15

    It is well established that hypoxia contributes to tumor progression in a hypoxia inducible factor-2α (HIF-2α)-dependent manner in renal cell carcinoma (RCC), yet the role of long noncoding RNAs (LncRNAs) involved in hypoxia-mediated RCC progression remains unclear. Here we demonstrate that LncRNA-SARCC (Suppressing Androgen Receptor in Renal Cell Carcinoma) is differentially regulated by hypoxia in a von Hippel-Lindau (VHL)-dependent manner both in RCC cell culture and clinical specimens. LncRNA-SARCC can suppress hypoxic cell cycle progression in the VHL-mutant RCC cells while derepress it in the VHL-restored RCC cells. Mechanism dissection reveals that LncRNA-SARCC can post-transcriptionally regulate androgen receptor (AR) by physically binding and destablizing AR protein to suppress AR/HIF-2α/C-MYC signals. In return, HIF-2α can transcriptionally regulate the LncRNA-SARCC expression via binding to hypoxia-responsive elements on the promoter of LncRNA-SARCC. The negative feedback modulation between LncRNA-SARCC/AR complex and HIF-2α signaling may then lead to differentially modulated RCC progression in a VHL-dependent manner. Together, these results may provide us a new therapeutic approach via targeting this newly identified signal from LncRNA-SARCC to AR-mediated HIF-2α/C-MYC signals against RCC progression.

  6. Bromodichloromethane induces cell proliferation in different tissues of male F344 rats by suppression of E-cadherin expression via hypermethylation or transcriptional activation of c-myc and cyclin D1.

    Science.gov (United States)

    Liao, Jing; Li, Xiao-Feng; Zhou, Shun-Chang; Luo, Yan; Liu, Ai-Lin; Lu, Wen-Qing

    2013-11-25

    The aim of this study was to investigate the mechanism of bromodichloromethane (BDCM) - induced cell proliferation in different tissues of male F344 rats. Rats were administered at doses of 0 and 100mg/kg/day BDCM dissolved in corn oil by gavage for 5 days/week for 1, 4, 8 and 12 weeks. Then the colon, kidney and liver were collected. No histologic lesions were observed in the colon of rats exposed to BDCM, while there were mild nephrotoxicity and marginal hepatotoxicity related to BDCM treatment. Moreover, BDCM enhanced cell proliferation in the colon and kidney but not in the liver. In colons, hypermethylation in E-cadherin promoter might be associated with inhibition of mRNA and protein expression after 12 weeks of BDCM exposure. In kidneys, BDCM decreased E-cadherin mRNA expression, accompanying with transcriptional activation of c-myc and cyclin D1. However, suppression of E-cadherin mRNA and protein expression occurred in the absence of significant changes in DNA methylation. Therefore, suppression of E-cadherin expression via hypermethylation or transcriptional activation of c-myc and cyclin D1 may be involved in BDCM-induced cell proliferation in different tissues of male F344 rats.

  7. E2F Transcription Factors Control the Roller Coaster Ride of Cell Cycle Gene Expression

    NARCIS (Netherlands)

    Thurlings, Ingrid; de Bruin, Alain

    2016-01-01

    Initially, the E2F transcription factor was discovered as a factor able to bind the adenovirus E2 promoter and activate viral genes. Afterwards it was shown that E2F also binds to promoters of nonviral genes such as C-MYC and DHFR, which were already known at that time to be important for cell growt

  8. Neuroprotective effects of prostaglandin A1 and its effect on IKK/IkB/NF-kB/c-myc signaling pathway in rat models of permanent focal cerebral ischemia

    Institute of Scientific and Technical Information of China (English)

    Hui-lingZHANG; Zhen-lunGU; Zheng-hongQIN

    2005-01-01

    AIM Prostaglandin A1(PGA1) is a cyclopentenone prostaglandin. Recently, we reported that PGA1 can inhibit excitotoxin-induced apoptosis of striatal neurons in vivo and rotenone-induced apoptosis ofcultured SH-SY5Y cells, suggesting that PGA1 may have neuroprotective efficacy, possibly mediated by inhibition of NF-kB activation. The present study evaluated the neuroprotective potential of PGA1 and its effect on IKK/I( B/NF-kB/c-myc signaling pathway in rat models of permanent focal cerebral ischemia. METHODS Permanent middle cerebral artery occlusion (pMCAO) model was constructed by intraluminal suture cannulation through the internal carotid artery in Wistar rats.

  9. The role of micro RNAs let7c, 100 and 218 expression and their target RAS, C-MYC, BUB1, RB, SMARCA5, LAMB3 and Ki-67 in prostate cancer

    Directory of Open Access Journals (Sweden)

    Sabrina T. Reis

    2013-05-01

    Full Text Available OBJECTIVE: The aim of this study is to verify the expression of proteins that are controlled by miR-let7c, 100 and 218 using immunohistochemistry in tissue microarray representative of localized and metastasized the lymph nodes and bone prostate cancer. METHODS: To verify the expression of proteins that are controlled by miR-let7c (C-MYC, BUB1, RAS 100 (SMARCA5, RB and 218 (LAMB3 and cell proliferation (Ki-67 we used immunohistochemistry and computerized image system ImageJ MacBiophotonics in three tissue microarrays representative of localized prostate cancer and lymph node and bone metastases. miRNA expression was evaluated by qRT-PCR using 60 paraffin blocks to construct the tissue microarray representative of localized disease. RESULTS: RAS expression was increased in localized prostate cancer and bone metastases compared to the lymph nodes (p=0.017. RB showed an increase in expression from localized prostate cancer to lymph node and bone metastasis (p=0.036. LAMB3 was highly expressed in localized and lymph node metastases (p<0.001. Cell proliferation evaluated by Ki-67 showed an increase from localized prostate cancer to metastases (p<0.001. We did not found any relationship between C-MYC (p=0.253, BUB1 (p=0.649 and SMARCA5 (p=0.315 protein expression with prognosis or tumor behavior. CONCLUSION: We found that the expression of RAS, RB, LAMB3 and Ki-67 changed in the different stages of prostate cancer. Furthermore, we confirmed the overexpression of the miRNAs let7c, 100 and 218 in localized prostate cancer but failed to show the control of protein expression by the putative controller miRNAs using immunohistochemistry.

  10. Possible mechanism for hepatitis B virus X gene to induce apoptosis of hepatocytes

    Institute of Scientific and Technical Information of China (English)

    Sheng-Jun Zhang; Hong-Ying Chen; Zhi-Xin Chen; Xiao-Zhong Wang

    2005-01-01

    AIM: To investigate the possible mechanism for HBV X gene to induce apoptosis of hepatocyte HL-7702 cells.METHODS: HBV X gene eukaryon expression vector pcDNA3-X was established and transfected into HL-7702 cells by lipid-mediated transfection, including transient and stable transfection. Positive clones were screened by incubating in the selective medium with 600 μg/mLG418 and named HL-7702/HBV-encoded X protein (HBx)cells. The expressions of Fas/FasL, Bax/Bcl-2, and c-myc mRNA were measured by semi-quantitative RT-PCR in HL-7702/HBx and control group, respectively.RESULTS: RT-PCR analysis confirmed that HBV X gene was transfected into HL-7702 cells successfully. By semiquantitative RT-PCR analysis, Bax and c-myc mRNA levels in HL-7702/HBx cells of transient transfection were significantly higher than those in control, FasL and c-myc mRNA levels in HL-7702/HBx cells of stable transfection were significantly higher than those in control, whereas the Bcl-2 mRNA levels in HL-7702/HBx cells of transient and stable transfection were significantly lower than those in control.CONCLUSION: HBV X gene may promote the apoptosis of hepatocytes by regulating the expressions of Fas/FasL,Bax/Bcl-2, and c-myc gene in a dose-dependent manner.

  11. HeLa和SiHa细胞中Skp2、p27和C-myc的表达%Expressions of Skp2、p27 and C-myc in HeLa and SiHa Cells

    Institute of Scientific and Technical Information of China (English)

    薛翔; 公丕军; 范引侠

    2012-01-01

    Objective: To test the expressions of S-phase kinase-associated protein 2 (Skp2), C-myc and p27 in HeLa and SiHa cells from the levels of RNA and protein and to investgate the meaning of those indexes in cervical cancerous cells. Methods:We tested the expressions of Skp2, p27 and C-myc in HeLa and SiHa cell lines by immunohistochemistry, western blotting as well as semiquantitative PCR . Results: Immunohistochemistry results showed that the expressions of Skp2 and C-myc were obviously stronger in HeLa cells than those in SiHa cells (P =0.032 and P = 0.026). While the expression of p27 was weaker in HeLa cells than that in SiHa cells (P=0.035). Western blot results showed that the expressions of endogenous Skp2 and C-myc protein in HeLa cells were as 2.8 and 1.5 times of SiHa cells respectively. However, the expression of p27 protein in SiHa cells was as 2.7 times of those in HeLa cells. RT-PCR results showed that the expression levels of endogenous Skp2 and C-myc mRNA in HeLa cells were higher than those in Si-Hha cells(P = 0.034 and P = 0.028, respectively), meanwhile, the expression of p27mRNA in SiHa cells was higher than that of HeLa cells (P=0.002). Conclusions: The expressions of Skp2 and C-myc in HeLa cells are obviously higher than those in SiHa cells. The expression of p27 in HeLa cells is lower than that in SiHa cells.%目的:检测S期激酶相关蛋白2( Skp2)、C-myc、p27在宫颈癌HeLa及SiHa细胞系中的表达,明确这些指标在宫颈癌细胞系表达的意义.方法:通过细胞免疫组化、Western blot、RT-PCR技术分析Skp2、p27和C-myc在蛋白和mRNA水平表达的差异.结果:免疫组化显示:HeLa细胞中Skp2和C-myc表达强度高于SiHa细胞(P=0.032和P=0.026),而HeLa细胞中p27蛋白表达弱于SiHa细胞(P=0.035).Western blot显示:在HeLa细胞中Skp2和C-myc蛋白表达分别是SiHa细胞表达量的2.8倍和1.5倍;而SiHa细胞中的p27蛋白的表达水平是He-La细胞中表达的2.7倍.RT-PCR结果

  12. Microarray analysis of E-box binding-related gene expression in young and replicatively senescent human fibroblasts.

    Science.gov (United States)

    Semov, Alexandre; Marcotte, Richard; Semova, Natalie; Ye, Xiangyun; Wang, Eugenia

    2002-03-01

    An E-box (CACGTG) designer microarray was developed to monitor a group of genes whose expressions share a particular regulatory mode. Sensitivity and specificity of microarray hybridization, as well as variability of microarray data, were evaluated. This designer microarray was used to generate expression profiles of E-box binding-related genes in WI-38 fibroblast cultures at three different growth states: low-passage replicating, low-passage contact-inhibited quiescent, and replicatively senescent. Microarray gene screening reveals that quiescent and senescent cells, in comparison with replicating ones, are characterized by downregulation of Pam, a protein associated with c-Myc, and upregulation of Mad family genes, Max dimerization proteins. Moreover, quiescence and senescence can be distinguished by increased expression of Irlb, c-Myc transcription factor, and Miz-1, c-Myc-interacting Zn finger protein 1, only in the former state. Senescence is characterized by downregulation of Id4, inhibitor of DNA binding 4, and Mitf, microphthalmia-associated transcription factor, in comparison with young replicating and quiescent states. Differential expression of genes detected by microarray hybridization was independently confirmed by reverse transcription polymerase chain reaction technique. Alterations in the expression of E-box-binding transcription factors and c-Myc-binding proteins demonstrate the importance of these genes in establishing the contact-inhibited quiescent or senescent phenotypes.

  13. Chromosomal and Extrachromosomal Instability of the cyclin D2 Gene is Induced by Myc Overexpression

    Directory of Open Access Journals (Sweden)

    Sabine Mai

    1999-08-01

    Full Text Available We examined the expression of cyclins D1, D2, D3, and E in mouse B-lymphocytic tumors. Cyclin D2 mRNA was consistently elevated in plasmacytomas, which characteristically contain Myc-activating chromosome translocations and constitutive c-Myc mRNA and protein expression. We examined the nature of cyclin D2 overexpression in plasmacytomas and other tumors. Human and mouse tumor cell lines that exhibited c-Myc dysregulation displayed instability of the cyclin D2 gene, detected by Southern blot, fluorescent in situ hybridization (FISH, and in extrachromosomal preparations (Hirt extracts. Cyclin D2 instability was not seen in cells with low levels of c-Myc protein. To unequivocally demonstrate a role of c-Myc in the instability of the cyclin D2 gene, a Myc-estrogen receptor chimera was activated in two mouse cell lines. After 3 to 4 days of Myc-ERTm activation, instability at the cyclin D2 locus was seen in the form of extrachromosomal elements, determined by FISH of metaphase and interphase nuclei and of purified extrachromosomal elements. At the same time points, Northern and Western blot analyses detected increased cyclin D2 mRNA and protein levels. These data suggest that Myc-induced genomic instability may contribute to neoplasia by increasing the levels of a cell cycle—regulating protein, cyclin D2, via intrachromosomal amplification of its gene or generation of extrachromosomal copies.

  14. 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

  15. Detection of c-myc amplification in formalin-fixed paraffin-embedded tumor tissue by chromogenic in situ hybridization (CISH).

    Science.gov (United States)

    Todorović-Raković, Nataša

    2013-01-01

    In situ hybridization (ISH) allows evaluation of genetic abnormalities, such as changes in chromosome number, chromosome translocations or gene amplifications, by hybridization of tagged DNA (or RNA) probes with complementary DNA (or RNA) sequences in interphase nuclei of target tissue. However, chromogenic in situ hybridization (CISH) is also applicable to formalin-fixed, paraffin-embedded (FFPE) tissues, besides metaphase chromosome spreads. CISH is similar to fluorescent in situ hybridization (FISH) regarding pretreatments and hybridization protocols but differs in the way of visualization. Indeed, CISH signal detection is similar to that used in immunohistochemistry, making use of a peroxidase-based chromogenic reaction instead of fluorescent dyes. In particular, tagged DNA probes are indirectly detected using an enzyme-conjugated antibody targeting the tags. The enzymatic reaction of the chromogenic substrate leads to the formation of strong permanent brown signals that can be visualized by bright-field microscopy at 40 × magnification. The advantage of CISH is that it allows the simultaneous observation of gene amplification and tissue morphology and the slides can be stored for a long time.

  16. Triphala Extract Suppresses Proliferation and Induces Apoptosis in Human Colon Cancer Stem Cells via Suppressing c-Myc/Cyclin D1 and Elevation of Bax/Bcl-2 Ratio

    Directory of Open Access Journals (Sweden)

    Ramakrishna Vadde

    2015-01-01

    Full Text Available Colon cancer is the second leading cause of cancer related deaths in the USA. Cancer stem cells (CSCs have the ability to drive continued expansion of the population of malignant cells. Therefore, strategies that target CSCs could be effective against colon cancer and in reducing the risk of relapse and metastasis. In this study, we evaluated the antiproliferative and proapoptotic effects of triphala, a widely used formulation in Indian traditional medicine, on HCT116 colon cancer cells and human colon cancer stem cells (HCCSCs. The total phenolic content, antioxidant activity, and phytochemical composition (LC-MS-MS of methanol extract of triphala (MET were also measured. We observed that MET contains a variety of phenolics including naringin, quercetin, homoorientin, and isorhamnetin. MET suppressed proliferation independent of p53 status in HCT116 and in HCCSCs. MET also induced p53-independent apoptosis in HCCSCs as indicated by elevated levels of cleaved PARP. Western blotting data suggested that MET suppressed protein levels of c-Myc and cyclin D1, key proteins involved in proliferation, and induced apoptosis through elevation of Bax/Bcl-2 ratio. Furthermore, MET inhibited HCCSCs colony formation, a measure of CSCs self-renewal ability. Anticancer effects of triphala observed in our study warrant future studies to determine its efficacy in vivo.

  17. Differential 14-3-3 sigma DNA methylation and expression in c-myc- and activated H-ras-transformed cells under r- and K-selection.

    Science.gov (United States)

    Sato, Hiroyuki; Nakamura, Yukari; Motokura, Toru

    2006-05-08

    We cloned rat 14-3-3 sigma, a mediator of p53 tumor suppressor, as a target of K-selection. 14-3-3 sigma expression is suppressed with DNA methylation in breast cancers while its overexpression with hypomethylation is frequent in pancreatic cancers. These opposite findings were recapitulated through r- and K-selection of transformed rat embryo fibroblasts. 14-3-3 sigma expression was suppressed with DNA methylation after r-selection and the gene was overexpressed and demethylated in K-selected cells. 5-aza-2'-deoxycytidine recovered 14-3-3 sigma expression in r-selected cells. The presence of heterogeneous methylation patterns and expression levels before selection suggests that different 14-3-3 sigma expression levels play a role as a prerequisite for selection and clonal evolution.

  18. AID-targeting and hypermutation of non-immunoglobulin genes does not correlate with proximity to immunoglobulin genes in germinal center B cells.

    Science.gov (United States)

    Gramlich, Hillary Selle; Reisbig, Tara; Schatz, David G

    2012-01-01

    Upon activation, B cells divide, form a germinal center, and express the activation induced deaminase (AID), an enzyme that triggers somatic hypermutation of the variable regions of immunoglobulin (Ig) loci. Recent evidence indicates that at least 25% of expressed genes in germinal center B cells are mutated or deaminated by AID. One of the most deaminated genes, c-Myc, frequently appears as a translocation partner with the Ig heavy chain gene (Igh) in mouse plasmacytomas and human Burkitt's lymphomas. This indicates that the two genes or their double-strand break ends come into close proximity at a biologically relevant frequency. However, the proximity of c-Myc and Igh has never been measured in germinal center B cells, where many such translocations are thought to occur. We hypothesized that in germinal center B cells, not only is c-Myc near Igh, but other mutating non-Ig genes are deaminated by AID because they are near Ig genes, the primary targets of AID. We tested this "collateral damage" model using 3D-fluorescence in situ hybridization (3D-FISH) to measure the distance from non-Ig genes to Ig genes in germinal center B cells. We also made mice transgenic for human MYC and measured expression and mutation of the transgenes. We found that there is no correlation between proximity to Ig genes and levels of AID targeting or gene mutation, and that c-Myc was not closer to Igh than were other non-Ig genes. In addition, the human MYC transgenes did not accumulate mutations and were not deaminated by AID. We conclude that proximity to Ig loci is unlikely to be a major determinant of AID targeting or mutation of non-Ig genes, and that the MYC transgenes are either missing important regulatory elements that allow mutation or are unable to mutate because their new nuclear position is not conducive to AID deamination.

  19. AID-targeting and hypermutation of non-immunoglobulin genes does not correlate with proximity to immunoglobulin genes in germinal center B cells.

    Directory of Open Access Journals (Sweden)

    Hillary Selle Gramlich

    Full Text Available Upon activation, B cells divide, form a germinal center, and express the activation induced deaminase (AID, an enzyme that triggers somatic hypermutation of the variable regions of immunoglobulin (Ig loci. Recent evidence indicates that at least 25% of expressed genes in germinal center B cells are mutated or deaminated by AID. One of the most deaminated genes, c-Myc, frequently appears as a translocation partner with the Ig heavy chain gene (Igh in mouse plasmacytomas and human Burkitt's lymphomas. This indicates that the two genes or their double-strand break ends come into close proximity at a biologically relevant frequency. However, the proximity of c-Myc and Igh has never been measured in germinal center B cells, where many such translocations are thought to occur. We hypothesized that in germinal center B cells, not only is c-Myc near Igh, but other mutating non-Ig genes are deaminated by AID because they are near Ig genes, the primary targets of AID. We tested this "collateral damage" model using 3D-fluorescence in situ hybridization (3D-FISH to measure the distance from non-Ig genes to Ig genes in germinal center B cells. We also made mice transgenic for human MYC and measured expression and mutation of the transgenes. We found that there is no correlation between proximity to Ig genes and levels of AID targeting or gene mutation, and that c-Myc was not closer to Igh than were other non-Ig genes. In addition, the human MYC transgenes did not accumulate mutations and were not deaminated by AID. We conclude that proximity to Ig loci is unlikely to be a major determinant of AID targeting or mutation of non-Ig genes, and that the MYC transgenes are either missing important regulatory elements that allow mutation or are unable to mutate because their new nuclear position is not conducive to AID deamination.

  20. 鸟氨酸脱羧酶和c-myc在胃癌及其癌前病变组织中的表达及意义%Expression of ornithine decarboxylase and c-myc in gastric cancer and premalignant lesions and its significance

    Institute of Scientific and Technical Information of China (English)

    魏小娟; 王云溪

    2016-01-01

    Objective:To detect the expression of ODC and c-myc in chronic superficial gastritis, intestinal metaplasia, atypical hy-perplasia and gastric carcinoma, to explore the correlation and significance of the expression of ODC and c-myc in gastric carcinoma and precancerous lesions.Methods:The expressions of ODC and c-myc were detected by RT-PCR and immunohistochemistry in 18 cases of chronic superficial gastritis( CSG) , 18 chronic atrophic gastritis with intestinal metaplasia CAG( with IM) ,12 gastric dysplasia ( DYS) and 30 gastric carcinoma ( GC) , to explore the correlation between ODC and c-myc and their relationship with precancerous gastric le-sions.Results:The expression of ODC in CAG with IM, DYS and GC was significantly higher than that in CSG(P<0.01).The expres-sion of c-myc was significantly higher in GC comparing with CSG and CAG with IM (P<0.01).In addition, ODC and c-myc positive immunostaining rates were significantly higher in poorly-differentiated GC than in well-differentiated GC (P<0.01).The expression of ODC was positively correlated with c-myc at different stages of gastric carcinogenesis.Conclusions:ODC may play an important role as carcinogenic factor, and c-myc promotes cell proliferation by inducing ODC expression.Detecting both markers together may help in ear-ly diagnosis of gastric carcinoma.%及蛋白的表达。结果:ODC mRNA及蛋白在萎缩性胃炎肠化生( CAG与IM)、不典型增生( DYS)及胃癌( GC)组织中的表达水平显著高于浅表性胃炎(CSG)(P<0.01)。 c-myc mRNA及蛋白在胃癌(GC)组织中的表达水平显著高于浅表性胃炎(CSG)、萎缩性胃炎肠化生(CAG with IM)(P<0.01),ODC和c-myc在中低分化腺癌的表达水平显著高于高分化腺癌(P<0.05)。 ODC与c-myc在胃粘膜癌变多阶段中的表达呈正相关( P<0.01)。结论:ODC作为致癌因子在胃癌发生中有重要作用,且c-myc通过促进ODC的

  1. FoxP3 Functions as a Novel Breast Cancer Suppressor Gene Through Cooperation with NFAT

    Science.gov (United States)

    2008-12-01

    Identification of a FOXP3-binding site in the 50 region of the MYC gene. The top panel is a diagram of the MYC gene ( Bossone et al., 1992), with the...Cancer Cell 11, 391–394. Bossone , S.A., Asselin, C., Patel, A.J., and Marcu, K.B. (1992). MAZ, a zinc finger protein, binds to c-MYC and C2 gene

  2. Indole-3-carbinol induces cMYC and IAP-family downmodulation and promotes apoptosis of Epstein-Barr virus (EBV)-positive but not of EBV-negative Burkitt's lymphoma cell lines.

    Science.gov (United States)

    Perez-Chacon, Gema; de Los Rios, Cristobal; Zapata, Juan M

    2014-11-01

    Indole-3-carbinol (I3C) is a natural product found in broadly consumed plants of the Brassica genus, such as broccoli, cabbage, and cauliflower, which exhibits anti-tumor effects through poorly defined mechanisms. I3C can be orally administered and clinical trials have demonstrated that I3C and derivatives are safe in humans. In this study we show that I3C efficiently induces apoptosis in cell lines derived from EBV-positive Burkitt's lymphomas (virus latency I/II), while it does not have any cytotoxic activity against EBV-negative Burkitt's lymphomas and immortalized EBV-infected lymphoblastoid cell lines (virus latency III). The effect of I3C in EBV-positive Burkitt's lymphoma is very specific, since only I3C and its C6-methylated derivative, but not other 3-substituted indoles, have an effect on cell viability. I3C treatment caused apoptosis characterized by loss of mitochondria membrane potential and caspase activation. I3C alters the expression of proteins involved in the control of apoptosis and transcription regulation in EBV-positive Burkitt's lymphoma cell lines. Among those, cMYC, cIAP1/2 and XIAP downmodulation at mRNA and protein level precede apoptosis induction, thus suggesting a role in I3C cytotoxicity. We also showed that I3C and, more particularly, its condensation dimer 3,3'-diindolylmethane (DIM) prolonged survival and reduced tumor burden of mice xenotransplanted with EBV-positive Burkitt's lymphoma Daudi cells. In summary these results, together with previous reports from clinical trials indicating the lack of toxicity in humans of I3C and derivatives, support the use of these compounds as a new therapeutic approach for treating patients with endemic (EBV-positive) Burkitt's lymphoma.

  3. Cloning and Preliminary Function Analysis of Xuhuai Goat c-Myc Promoter%徐淮山羊c-Myc基因启动子的克隆及其功能的初步分析

    Institute of Scientific and Technical Information of China (English)

    韦光辉; 左其生; 李东; 张亚妮; 刘志永; 朱睿; 邱峰龙; 李碧春

    2014-01-01

    本研究旨在确定徐淮山羊c-Myc基因启动子区域,找出该基因启动子的核心调控区,初步探讨c-Myc基因的表达调控机制.根据UCSC基因组数据库已公布的绵羊c-Myc基因的启动子序列,设计特异性PCR引物扩增c-Myc基因的一系列启动子缺失片段,定向克隆至pEGFP-N1和PGL3-c-Myc,分别转染gFF、COS7及P19细胞,并进行TSA和NFAT1诱导,同时对-402~-249 bp区域的转录因子SP1结合位点进行定点突变,最后进行双荧光报告基因活性检测.结果表明,徐淮山羊c-Myc基因5′侧翼区-1 334~+1 bp区域的启动子活性最强,-402~+1 bp区域为c-Myc基因启动子基本活性区域.进一步研究发现,-1 334~-971 bp、-587~-147 bp区域存在正调控元件,-1 976~-1 334 bp、-971~-587 bp区域存在负调控元件.TSA和NFAT1均能增强PMyc启动子的活性,SP1结合位点定点突变后,启动子活性降低.本试验通过构建包含c-Myc基因启动子不同片段的重组报告基因载体并比较其转录活性,确定了c-Myc基因启动子的核心区域,发现转录因子SP1是c-Myc基因启动子核心区域的调控元件,为进一步研究c-Myc基因的表达调控机制奠定了基础.

  4. Development of gene microarray in screening differently expressed genes in keloid and normal-control skin

    Institute of Scientific and Technical Information of China (English)

    陈伟; 付小兵; 葛世丽; 孙晓庆; 周岗; 赵志力; 盛志勇

    2004-01-01

    Background Keloid is an intricate lesion that is probably regulated by many genes. In this study, the authors used the technique of complementary DNA (cDNA) microarray to analyse abnormal gene expression in keloids and normal control skins. Methods The polymerase chain reaction (PCR) products of 8400 genes were spotted in an array on chemical-material-coated-glass plates. The DNAs were fixed on the glass plates. The total RNAs were isolated from freshly excised human keloid and normal control skins, and the mRNAs were then purified. The mRNA from both keloid and normal control skins were reversely transcribed to cDNAs, with the incorporation of fluorescent dUTP, for preparing the hybridisation probes. The mixed probes were then hybridised to the cDNA microarray. After thorough washing, the cDNA microarray was scanned for differing fluorescent signals from two types of tissues. Gene expression of tissue growth factor-β1 (TGF-β1) and of c-myc was detected with both RT-PCR and Northern blot hybridisation to confirm the effectiveness of cDNA microarray. Results Among the 8400 human genes, 402 were detected with different expression levels between keloid and normal control skins. Two hundred and fifty genes, including TGF-β1 and c-myc, were up-regulated and 152 genes were down-regulated. Higher expressions of TGF-β1 and c-myc in keloid were also revealed using RT-PCR and Northern blot methods. Conclusion cDNA microarray analysis provides a powerful tool for investigating differential gene expression in keloid and normal control skins. Keloid is a complicated lesion with many genes involved.

  5. Hypoxia-inducible factor-2 alpha promotes the proliferation of human placenta-derived mesenchymal stem cells through the MAPK/ERK signaling pathway

    Science.gov (United States)

    Zhu, Chengxing; Yu, Jiong; Pan, Qiaoling; Yang, Jinfeng; Hao, Guangshu; Wang, Yingjie; Li, Lanjuan; Cao, Hongcui

    2016-01-01

    Human placenta-derived mesenchymal stem cells (hPMSCs) reside in a physiologically low-oxygen microenvironment. Hypoxia influences a variety of stem cell cellular activities, frequently involving hypoxia-inducible factor-2 alpha (HIF-2α). This research showed that hPMSCs cultured in hypoxic conditions (5% O2) exhibited a more naïve morphology and had a higher proliferative capability and higher HIF-2α expression than hPMSCs cultured in normoxic conditions (21% O2). Similar to the hypoxic cultures, hPMSCs over-expressing HIF-2α showed higher proliferative potential and higher expression of CCND1 (CyclinD1), MYC (c-Myc), POU5F1 (Oct4) and the components of the MAPK/ERK pathway. In contrast, these genes were down-regulated in the HIF-2α-silenced hPMSCs. After adding the MAPK/ERK inhibitor PD0325901, cell growth and the expression of CCND1 and MYC were inhibited. Furthermore, the chromatin immunoprecipitation (ChIP) assay and electrophoretic mobility shift assay (EMSA) showed that HIF-2α bound to the MAPK3 (ERK1) promoter, indicative of its direct regulation of MAPK/ERK components at the transcriptional level during hPMSC expansion. Taken together, our results suggest that HIF-2α facilitated the preservation of hPMSC stemness and promoted their proliferation by regulating CCND1 and MYC through the MAPK/ERK signaling pathway. PMID:27765951

  6. [cDNA cloning and sequence analysis of pluripotency genes in tree shrews (Tupaia belangeri)].

    Science.gov (United States)

    Wang, Cai-Yun; Ma, Yun-Han; He, Da-Jian; Yang, Shi-Hua

    2013-04-01

    In this paper, partial sequences of the tree shrew (Tupaia belangeri) Klf4, Sox2, and c-Myc genes were cloned and sequenced, which were 382, 612, and 485 bp in length and encoded 127, 204, and 161 amino acids, respectively. Whereas, their cDNA sequence identities with those of human were 89%, 98%, and 89%, respectively. Their phylogenetic tree results indicated different topologies and suggested individual evolutional pathways. These results can facilitate further functional studies.

  7. Expression and significance of AP-2α,Bcl-2 and C-myc in severe preeclampsia%AP-2α、Bcl-2及C-myc在重度子痫前期患者胎盘组织中的表达及意义

    Institute of Scientific and Technical Information of China (English)

    张玲; 曾宪旭; 张展; 常爱民

    2016-01-01

    目的:探讨转录因子激活蛋白-2α( AP-2α)与B淋巴细胞瘤-2基因( Bcl-2)、C-myc在重度子痫前期胎盘组织中的表达及其意义。方法采用免疫组化法及实时荧光定量-PCR( RT-PCR)的方法,检测重度子痫前期组胎盘组织及正常对照组胎盘组织中AP-2α及Bcl-2、C-myc蛋白及mRNA的表达。结果重度子痫前期组胎盘组织中AP-2α蛋白明显高于正常对照组(P﹤0.05),Bcl-2和C-myc蛋白表达明显低于正常对照组(P﹤0.05);重度子痫前期组胎盘组织中AP-2α mRNA明显高于正常对照组(P﹤0.05),C-myc和Bcl-2 mRNA表达明显低于正常对照组( P﹤0.05)。结论 AP-2α和Bcl-2、C-myc在重度子痫前期患者胎盘组织中的差异表达参与重度子痫前期的病理生理过程。%Objective To investigate the role of AP-2α,Bcl-2 and C-myc proein and mRNA in severe preeclampsia. Methods The expression of AP-2α,Bcl-2 and C-myc in placental tissues in se-vere preeclamptic pregnancies and normotensive pregnancies were analyzed by using immunohistochemis-try and RT-PCR. Results The positive expression of AP-2α for placenta trophoblast in severe pre-eclampsia was significantly higher than that in control group( P﹤0. 05 ),while the positive expressions of Bcl-2 and C-myc were significantly lower than those in control group( P﹤0. 05 ). The expression of AP-2αmRNA for placenta tissue in severe preeclampsia was significantly higher than that in control group ( P﹤0. 05 ),while the expressions of Bcl-2 and C-myc mRNA were significantly lower than those in con-trol group( P﹤0. 05 ). Conclusions AP-2αand Bcl-2 ,C-myc participate in the pathological process of preeclampsia.

  8. Effects of valsartan and spironolactone on the expression of c-myc in the left ventricle of renovascular hypertension rats.%缬沙坦与螺内酯对肾血管性高血压大鼠左室c-myc表达的影响

    Institute of Scientific and Technical Information of China (English)

    王圣; 刘宇飞; 曲鹏

    2011-01-01

    Objective To assess the roles of the local renin-angiotensin-aldosterone system (RAAS) and mechanical load in the expression of c-myc in hypertrophied myocardium of hypertension. Methods Two-kidney,one-clip (2KlC) renovascular hypertension was induced in Sprague-Dawley rats. The rats were randomized into untreated hypertension group (H group), spironolactone group (gorged spironolactone 50 mg/kg·day, S group), valsartan group (gorged valsanan 30 mg/kg·day, V group), and spironolactone plus valsartan group (gorged spironolactone 50 mg/kg·day and valsartan 30m g/kg·day at the same time, S+V group). Sham-operated rats served as controls (C group). The changes of heart structure and function in all groups were observed with echocardiogram. Left ventricle concentration of angiotensin Ⅱ(Ang Ⅱ) and ALD was assessed by radioimmunoassay. Immunohistochemistry was adopted to examine the protein expression of c-myc. Results After 8 weeks treatment, carotid systolic pressure, .MESS (meridian end systolic stress), LVPWd(left ventricular posterior wall thickness at end diastolic), IVSd (interventricular septal thickness at end diastolic) in V group and S-V group were decreased significantly compared with those in H group and S group (P<0.05). The left ventricle concentration of Ang Ⅱ was much lower in S group, V group and S-V group than that in It group (p<0.05). The expression of c-myc was much higher in H group and S group than that in C group, V group and S+V group (P<0.01). The expression of c-myc was positively related to carotid systolic pressure after 8 weeks treatment (r=0.848, P<0.01). Significant correlation was also present between MESS and the expression of c-myc (r=0.580,P<0.01). No correlation was found between Ang Ⅱ and the expression ofc-myc. Conclusion The increasing of mechanical load is an important factor inducing the persistent expression of c-myc in left ventricle cardiomyocytes of renovascular hypertension rats. The persistent

  9. 伽玛射线诱导脑膜瘤细胞凋亡和影响原癌基因c-myc的表达%Effects of gamma-ray on apoptosis and expression of c-myc protooncogene of meningioma cells

    Institute of Scientific and Technical Information of China (English)

    陈春美; 陈建乐; 韦浩; 张伟强; 蔡刚峰; 王春华; 王锐; 石松生; 杨卫忠

    2013-01-01

    目的 观察不同剂量伽玛(γ)射线诱导脑膜瘤细胞凋亡和原癌基因c-myc表达变化.方法 采用机械分离法获得稳定生长脑膜瘤细胞的离体培养细胞株,根据不同照射剂量分为4组,照射组分别接受中心剂量为2.00、5.00、8.22、13.33 Gy,设立对照组,剂量为0,照射后荧光显微镜观察细胞形态变化,流式细胞术检测细胞周期和凋亡率,Westem blot法检测c-myc蛋白的表达变化.结果 对照组、照射1组、2组、3组及4组细胞凋亡率分别为:(3.73±0.25)%、(4.07±0.29)%、(9.81±1.66)%、(21.63±3.08)%、(8.27±1.61)%;c-myc蛋白表达分别为:0、11±0.01、0.12±0.01、0.19 ±0.02、0.31±0.08、0.09±0.01;对照组和中心剂量2 Gy组照射后细胞形态、细胞周期、凋亡率和c-myc蛋白表达差异无统计学意义(P>0.05);中心剂量分别为5.00 Gy和8.22 Gy组细胞出现凋亡特征,细胞周期G0/G1和G2/M期细胞数量逐渐增多,细胞凋亡率升高,c-myc蛋白表达增多,与对照组比较差异均有统计学意义(P<0.05);剂量为13.33 Gy组,细胞以坏死为主,S期细胞增多,c-myc蛋白表达减少.结论 一定剂量的伽玛刀射线能够诱导脑膜瘤细胞进入凋亡,原癌基因c-myc在此过程中可能发挥促进脑膜瘤细胞进入凋亡过程.%Objective To investigate the apoptosis of meningioma cell and changes of the expression of c-myc protooncogene after gama ray radiation.Methods The isolated and cultured meningioma cells with stable growth were obtained from a patient with meningiomas by mechanical separation,and those cells were divided into 4 groups with the radiation center doses of 2.00,5.00,8.22,and 13.33 Gy respectively.There was a control group without radiation.Meningioma cell morphology was observed under fluorescent microscope.Flow cytometry was used to examine the cell cycle and apoptosis.The expression of c-myc protein was detected by using Western blotting.Results The cell apoptosis rate in

  10. A Functional Screen for Myc-Responsive Genes Reveals Serine Hydroxymethyltransferase, a Major Source of the One-Carbon Unit for Cell Metabolism

    Science.gov (United States)

    Nikiforov, Mikhail A.; Chandriani, Sanjay; O'Connell, Brenda; Petrenko, Oleksi; Kotenko, Iulia; Beavis, Andrew; Sedivy, John M.; Cole, Michael D.

    2002-01-01

    A cDNA library enriched with Myc-responsive cDNAs but depleted of myc cDNAs was used in a functional screen for growth enhancement in c-myc-null cells. A cDNA clone for mitochondrial serine hydroxymethyltransferase (mSHMT) that was capable of partial complementation of the growth defects of c-myc-null cells was identified. Expression analysis and chromatin immunoprecipitation demonstrated that mSHMT is a direct Myc target gene. Furthermore, a separate gene encoding the cytoplasmic isoform of the same enzyme is also a direct target of Myc regulation. SHMT enzymes are the major source of the one-carbon unit required for folate metabolism and for the biosynthesis of nucleotides and amino acids. Our data establish a novel functional link between Myc and the regulation of cellular metabolism. PMID:12138190

  11. Ataxia-telangiectasia group D complementing gene (ATDC promotes lung cancer cell proliferation by activating NF-κB pathway.

    Directory of Open Access Journals (Sweden)

    Zhong-Ping Tang

    Full Text Available Previous studies suggested Ataxia-telangiectasia group D complementing gene (ATDC as an oncogene in many types of cancer. However, its expression and biological functions in non-small cell lung cancer (NSCLC remain unclear. Herein, we investigated its expression pattern in 109 cases of human NSCLC samples by immunohistochemistry and found that ATDC was overexpressed in 62 of 109 NSCLC samples (56.88%. ATDC overexpression correlated with histological type (p<0.0001, tumor status (p = 0.0227 and histological differentiation (p = 0.0002. Next, we overexpressed ATDC in normal human bronchial epithelial cell line HBE and depleted its expression in NSCLC cell lines A549 and H1299. MTT and colony formation assay showed that ATDC overexpression promoted cell proliferation while its depletion inhibited cell growth. Furthermore, cell cycle analysis showed that ATDC overexpression decreased the percentage of cells in G1 phase and increased the percentage of cells in S phase, while ATDC siRNA treatment increased the G1 phase percentage and decreased the S phase percentage. Further study revealed that ATDC overexpression could up-regulate cyclin D1 and c-Myc expression in HBE cells while its depletion down-regulated cyclin D1 and c-Myc expression in A549 and H1299 cells. In addition, ATDC overexpression was also associated with an increased proliferation index, cyclin D1 and c-Myc expression in human NSCLC samples. Further experiments demonstrated that ATDC up-regulated cyclin D1 and c-Myc expression independent of wnt/β-catenin or p53 signaling pathway. Interestingly, ATDC overexpression increased NF-κB reporter luciferase activity and p-IκB protein level. Correspondingly, NF-κB inhibitor blocked the effect of ATDC on up-regulation of cyclin D1 and c-Myc. In conclusion, we demonstrated that ATDC could promote lung cancer proliferation through NF-κB induced up-regulation of cyclin D1 and c-Myc.

  12. EFFECTS OF IFN-a COMBINED WITH IL-6 ON GROWTH AND EXPRESSION OF THE GENES RELATED TO CELL-GROWTH AND APOPTOSIS OF BONE MARROW CELLS FROM PATIENTS WITH CML

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Objective: To investigate the effects of interferon-a (IFN-a ) and IFN-a combined with interleukin-6 (IL-6) on growth and expression of bcr-abl, bcl-2 and c-myc genes in the mononuclear cells (MNCs) from bone marrow (BM) of patients with chronic myelogenous leukemia (CML). Methods: MNCs were collected from BM of the patients with CML in chronic phase by centrifugation in lymphocyte separation medium and cultured in liquid with IFN-a (200U/ml) or IFN-a (200U/ml) plus IL-6 (100 ng/ml). The growing cells were counted every day. The expression levels of b -actin, bcr-abl, bcl-2 and c-myc genes in the MNCs incubated for 24 h were detected by reverse transcriptase-polymerase chain reaction (RT-PCR) and relatively quantitative analysis of the amplified fragments by optical density scanning for the bands on gel. Results: The cell growth was markedly suppressed by IFN-a but the degree of cell-growth inhibition was slightly decreased by IL-6 on the basis of IFN-a effect. The expression of bcr-abl chimeric gene was intensely inhibited by IFN-a or IFN-a plus IL-6. The expression of bcl-2 gene was suppressed by either IFN-a or IFN-a plus IL-6, whereas that of c-myc gene was also inhibited by IFN-a but strongly elevated by IL-6 on the basis of IFN-a action. Conclusions: Both IFN-a and IFN-a plus IL-6 can inhibit the expression of anti-apoptosis gene such as bcr-abl and bcl-2 and regulate the expression of the gene related to cell proliferation and differentiation such as c-myc. Either IFN-a or IFN-a combined with IL-6 will serve as a trustful strategy of clinical treatment for CML.

  13. Candidate gene analysis using imputed genotypes: cell cycle single-nucleotide polymorphisms and ovarian cancer risk

    DEFF Research Database (Denmark)

    Goode, Ellen L; Fridley, Brooke L; Vierkant, Robert A;

    2009-01-01

    Polymorphisms in genes critical to cell cycle control are outstanding candidates for association with ovarian cancer risk; numerous genes have been interrogated by multiple research groups using differing tagging single-nucleotide polymorphism (SNP) sets. To maximize information gleaned from...... existing genotype data, we conducted a combined analysis of five independent studies of invasive epithelial ovarian cancer. Up to 2,120 cases and 3,382 controls were genotyped in the course of two collaborations at a variety of SNPs in 11 cell cycle genes (CDKN2C, CDKN1A, CCND3, CCND1, CCND2, CDKN1B, CDK2......, and rs3212891; CDK2 rs2069391, rs2069414, and rs17528736; and CCNE1 rs3218036. These results exemplify the utility of imputation in candidate gene studies and lend evidence to a role of cell cycle genes in ovarian cancer etiology, suggest a reduced set of SNPs to target in additional cases and controls....

  14. Cohesin modulates transcription of estrogen-responsive genes.

    Science.gov (United States)

    Antony, Jisha; Dasgupta, Tanushree; Rhodes, Jenny M; McEwan, Miranda V; Print, Cristin G; O'Sullivan, Justin M; Horsfield, Julia A

    2015-03-01

    The cohesin complex has essential roles in cell division, DNA damage repair and gene transcription. The transcriptional function of cohesin is thought to derive from its ability to connect distant regulatory elements with gene promoters. Genome-wide binding of cohesin in breast cancer cells frequently coincides with estrogen receptor alpha (ER), leading to the hypothesis that cohesin facilitates estrogen-dependent gene transcription. We found that cohesin modulates the expression of only a subset of genes in the ER transcription program, either activating or repressing transcription depending on the gene target. Estrogen-responsive genes most significantly influenced by cohesin were enriched in pathways associated with breast cancer progression such as PI3K and ErbB1. In MCF7 breast cancer cells, cohesin depletion enhanced transcription of TFF1 and TFF2, and was associated with increased ER binding and increased interaction between TFF1 and its distal enhancer situated within TMPRSS3. In contrast, cohesin depletion reduced c-MYC mRNA and was accompanied by reduced interaction between a distal enhancer of c-MYC and its promoters. Our data indicates that cohesin is not a universal facilitator of ER-induced transcription and can even restrict enhancer-promoter communication. We propose that cohesin modulates transcription of estrogen-dependent genes to achieve appropriate directionality and amplitude of expression.

  15. Genomic-wide analysis of lymphatic metastasis-associated genes in human hepatocellular carcinoma

    Institute of Scientific and Technical Information of China (English)

    Chun-Feng Lee; Zhi-Qiang Ling; Ting Zhao; Shih-Hua Fang; Weng-Cheng Chang; San-Chih Lee; Kuan-Rong Lee

    2009-01-01

    AIM: To identify the genes related to lymph node metastasis in human hepatocellular carcinoma (HCC), 32 HCC patients with or without lymph node metastasis were investigated by high-throughput microarray comprising 886 genes.METHODS: The samples of cancerous and non-cancerouspaired tissue were taken from 32 patients with HCC who underwent hepatectomy with lymph node dissection. Total RNA was extracted from the cells obtained by means of laser microdissection (LCM) and was amplified by the T7-based amplification system. Then, the amplified samples were applied in the cDNA microarray comprising of 886 genes.RESULTS: The results demonstrated that 25 upregulated genes such as cell membrane receptor,intracellular signaling and cell adhesion related genes,and 48 down-regulated genes such as intracellular signaling and cell cycle regulator-related genes,were correlated with lymph node metastasis in HCC. Amongst them were included some interesting genes, such as MET, EPHA2, CCND1, MMP2, MMP13,CASP3, CDH1, and PTPN2. Expression of 16 genes ( MET, CCND1, CCND2, VEGF, KRT18, RFC4, BIRC5,CDC6, MMP2, BCL2A1, CDH1, VIM, PDGFRA, PTPN2,SLC25A5 and DSP) were further confirmed by real-time quantitative reverse transcriptional polymerase chain reaction (RT-PCR).CONCLUSION: Tumor metastasis is an important biological characteristic, which involves multiple genetic changes and cumulation. This genome-wide information contributes to an improved understanding of molecular alterations during lymph node metastasis in HCC. It may help clinicians to predict metastasis of lymph nodes and assist researchers in identifying novel therapeutic targets for metastatic HCC patients.

  16. Validity of multiplex biomarker model of 6 genes for the differential diagnosis of thyroid nodules

    Directory of Open Access Journals (Sweden)

    Ducena Kristine

    2011-06-01

    Full Text Available Abstract Background Currently the cytological examination of fine needle aspiration (FNA biopsies is the standard technique for the pre-operative differential diagnosis of thyroid nodules. However, the results may be non-informative in ~20% of cases due to an inadequate sampling and the lack of highly specific, measurable cytological criteria, therefore ancillary biomarkers that could aid in these cases are clearly needed. The aim of our study was to evaluate the mRNA expression levels of 8 candidate marker genes as the diagnostic biomarkers for the discrimination of benign and malignant thyroid nodules and to find a combination of biomarkers with the highest diagnostic value. Materials and methods mRNA expression levels of eight candidate marker genes - BIRC5, CCND1, CDH1, CITED1, DPP4, LGALS3, MET and TFF3 was measured by real-time RT-PCR in paired nodular and surrounding normal thyroid tissue specimens of 105 consecutive patients undergoing thyroid surgery and compared between different types of thyroid lesions. Results Significant differences in the mRNA expression levels between the normal and malignant thyroid tissues and between benign and malignant nodules were found for BIRC5, CCND1, CITED1, DPP4, LGALS3, MET and TFF3, but not CDH1. On a single gene basis, relative quantity (RQ of LGALS3 had the highest diagnostic value for the discrimination of malignant and benign thyroid nodules (AUC = 0.832, P LGALS3 was RQ sum of LGALS3 and BIRC5 (AUC = 0.841, P LGALS3, BIRC5, TFF3, CCND1, MET and CITED1 that had considerably higher specificity than a single marker or two marker gene-based models (AUC = 0.895, P Conclusions This study confirmed that mRNA expression levels of 7 out of 8 candidate genes analysed have a diagnostic value for the distinction of benign and malignant thyroid nodules. The multiplex biomarker model based on 6 genes outperformed a single marker or two marker-based models and warrants feasibility studies on FNA biopsies and

  17. 通脉汤方对实验性动脉粥样硬化家兔胸主动脉表皮生长因子受体和c-myc基因表达的影响%Effect of Tongmai Recipe on Epidermal Growth Factor Receptor and Protooncogene c-myc mRNA Expression in Aorta of Atherosclerotic Rabbit

    Institute of Scientific and Technical Information of China (English)

    张娟; 孙明; 周宏研

    2007-01-01

    目的 探讨通脉方对实验性动脉粥样硬化家兔胸主动脉表皮生长因子受体和c-myc基因表达的影响.方法 日本大耳白兔40只,随机分为4组:①对照组10只,以普通饲料喂养,每日两次;②模型组10只,以高胆固醇饲料[胆固醇0.5 g/(kg·d)、蛋黄2 g/(kg·d)和猪油2 g/(kg·d)]喂养,每日两次;③通脉汤方低剂量组(简称低剂量组)10只,高胆固醇饲料喂养(剂量同模型组),同时予通脉汤方灌胃,每只剂量相当于生药7.3 g/(kg*d),分上下午两次给药;④通脉汤方高剂量组(简称高剂量组)10只,高胆固醇饲料喂养(剂量同模型组),同时予通脉汤方灌胃,每只剂量相当于生药21.9 g/(kg·d),分上下午两次给药;共喂养16周.运用免疫组织化学染色法检测主动脉表皮生长因子受体的表达,同时用内参比逆转录聚合酶链反应定量分析c-myc mRNA在主动脉的表达.结果 模型组主动脉表皮生长因子受体及c-myc mRNA表达显著高于对照组(分别为0.327±0.030比0.209±0.006,P0.05;0.44±0.09比0.52±0.11 P>0.05).结论 ①动脉粥样硬化时促进血管平滑肌细胞增殖的表皮生长因子受体及原癌基因c-myc mRNA表达增强.②通脉汤方通过抑制血管壁表皮生长因子受体及c-myc基因的表达,从而抑制血管平滑肌细胞增殖.

  18. Polymorphisms in apoptosis and cell cycle control genes and risk of brain tumors in adults.

    Science.gov (United States)

    Rajaraman, Preetha; Wang, Sophia S; Rothman, Nathaniel; Brown, Merideth M; Black, Peter M; Fine, Howard A; Loeffler, Jay S; Selker, Robert G; Shapiro, William R; Chanock, Stephen J; Inskip, Peter D

    2007-08-01

    Despite the potential importance of the cell cycle and apoptosis pathways in brain tumor etiology, little has been published regarding brain tumor risk associated with common gene variants in these pathways. Using data from a hospital-based case-control study conducted by the National Cancer Institute between 1994 and 1998, we evaluated risk of glioma (n = 388), meningioma (n = 162), and acoustic neuroma (n = 73) with respect to 12 single nucleotide polymorphisms from 10 genes involved in apoptosis and cell cycle control: CASP8, CCND1, CCNH, CDKN1A, CDKN2A, CHEK1, CHEK2, MDM2, PTEN, and TP53. We observed significantly decreased risk of meningioma with the CASP8 Ex14-271A>T variant [odds ratio (OR)(AT), 0.8; 95% confidence interval (95% CI), 0.5-1.2; OR(AA), 0.5; 95% CI, 0.3-0.9; P(trend) = 0.03] and increased risk of meningioma with the CASP8 Ex13+51G>C variant (OR(GC), 1.4; 95% CI, 0.9-2.1; OR(CC), 3.6; 95% CI, 1.0-13.1; P(trend) = 0.04). The CT haplotype of the two CASP8 polymorphisms was associated with significantly increased risk of meningioma (OR, 1.7; 95% CI, 1.1-2.6), but was not associated with risk of glioma or acoustic neuroma. The CCND1 Ex4-1G>A variant was associated with increased risk for glioma, and the Ex8+49T>C variant of CCNH was associated with increased risk of glioma and acoustic neuroma. The MDM2 Ex12+162A>G variant was associated with significantly reduced risk of glioma. Our results suggest that common variants in the CASP8, CCND1, CCNH, and MDM2 genes may influence brain tumor risk. Future research in this area should include more detailed coverage of genes in the apoptosis/cell cycle control pathways.

  19. Temporal repression of endogenous pluripotency genes during reprogramming of porcine induced pluripotent stem cells

    DEFF Research Database (Denmark)

    Hall, Vanessa Jane; Christensen, Marianne; Rasmussen, Mikkel Aabech;

    2012-01-01

    transgenes on the expression of the porcine endogenous pluripotency machinery. Endogenous and exogenous gene expression of OCT4, NANOG, SOX2, KLF4, and cMYC was determined at passages 5, 10, 15, and 20, both in cells cultured at 1¿µg/mL doxycycline or 4¿µg/mL doxycycline. Our results revealed that endogenous....... Despite the ability for some endogenous genes to be expressed in these lines, the piPSC-like cells still cannot be maintained without doxycycline, indicating that the culture system of piPSCs may not be optimal or that the reprogramming factor combination used may not currently be optimal for maintaining...

  20. Sodium Iodide Symporter Gene Transfer for Imaging and Ablation of Prostate Cancer

    Science.gov (United States)

    2005-01-01

    MMTV-c-myc X MMTV-v-Ha-ras’ 45 3 0 (0) 0 0 N/A DMBA + pituitary isograft only’ 41 5 0 (0) 0 0 N/A PM, Plasma membrane; C, cytoplasm; N/A, not applicable...carcinogen and implantation of pituitary isograft . Prostate steroid binding protein C3 (1) promoter driving SV40 large T antigen gene. d p53 null...mammary explants implanted in wild-type mice treated with DMBA and pituitary isograft . ’Whey acidic protein promoter driving IGF gene. fBitransgenic mice

  1. Effect of Selenium, molybdenum and boron on ameloblast morphology and the expression of PCMA,C-MYC in fluorosis rat%硒、钼、硼对氟中毒大鼠成釉细胞形态及PCNA、C-myc表达变化的影响

    Institute of Scientific and Technical Information of China (English)

    汤晔; 陈黎明

    2011-01-01

    目的 观察硒、钼、硼对氟中毒大鼠成釉细胞形态及增殖细胞核抗原(PCNA),C-myc 基因表达变化的影,气方法大鼠分组均喂以含F-45 mg/L的蒸馏水及含不同浓度硒、钼、硼的饲料,建立微量元素拮抗氟中毒的大鼠模型.采用HE染色及免疫组化的方法观察氟对成釉细胞的影响,采用图像分析技术时免疫组化结果进行量化分析.结果 实验组成釉细胞形态较正常,PCNA表达增强,C-myc表达减弱.结论 硒、钼、硼减轻氟毒性的机制可能与通过拮抗氟引起的C-myc表达增强、PCNA表达减弱等作用有关.

  2. Influence of DNA methyltransferase 3b on the expression of STAT1 and C-myc and the methylation of promoters in human hepatocellular carcinolna cell line%DNA甲基转移酶3b对肝癌细胞株中STAT1及其下游基因c-myc的表达和启动子甲基化的影响

    Institute of Scientific and Technical Information of China (English)

    司亚卿; 王佳辰; 王家祥

    2009-01-01

    Objective To invetigate the influence of DNMT3b of SMMC7721 on the expression of STAT1 and c-myc and the methylation of promoters,and further study the functions of DNMT3b.Methods DNMT3b was silenced by siRNA in human hepatocellular carcinoma cell line SMMC-7721.Westem blotting was performed to evaluate the expression of sTAT1 and c-myc.Methylation specific PCR(MSP)was performed to investigate whether the promoters of STAT1 and c-myc were methylated.Results Western blot analysis showed that the expression of DNMT3b and c-myc in DNMT3bsiRNA transfection group was decreased significantly as compared with the control group,and the expression of STATI increased significanfly.There was no significant difierence in the state of methylation between the transfection and control groups.Conclusion DNMT3b may regulate the expression STAT1 and c-myc in SMMC7721 cells,but not change the state of methylation,suggesting DNMT3b may play roles as transcription factors.%目的 探讨DNA甲基转移酶3b(DNMT3b)在人肝癌细胞株(SMMC7721)中对STAT1和c-myc基因表达及其启动子甲基化水平的影响,并进一步探讨DNMT3b的作用.方法 用DNMT3bsiRNA抑制DNMT3b在SMMC7721细胞系中的表达,用Western blot技术检测其转染前后DNMT3b及STAT1和c-myc基因的表达.应用甲基化特异性PCR(MSP)技术分别检测两组细胞中STAT1和c-myc基因启动子区的甲基化状况.结果 转染DNMT3bsiRNA的实验组DNMT3b表达水平明显低于对照组,STAT1基因的表达高于对照组;c-myc基因的表达低于对照组.两组中STAT1和c-myc基因启动子区甲基化状态无差异,均未发生甲基化.结论 DNM33b可以调节STAT1和c-myc基因的表达,而不改变基因的甲基化状态,可能发挥了转录调控因子的作用.

  3. BRCA1 transcriptionally regulates genes associated with the basal-like phenotype in breast cancer.

    Science.gov (United States)

    Gorski, Julia J; James, Colin R; Quinn, Jennifer E; Stewart, Gail E; Staunton, Kieran Crosbie; Buckley, Niamh E; McDyer, Fionnuala A; Kennedy, Richard D; Wilson, Richard H; Mullan, Paul B; Harkin, D Paul

    2010-08-01

    Expression profiling of BRCA1-deficient tumours has identified a pattern of gene expression similar to basal-like breast tumours. In this study, we examine whether a BRCA1-dependent transcriptional mechanism may underpin the link between BRCA1 and basal-like phenotype. In methods section, the mRNA and protein were harvested from a number of BRCA1 mutant and wild-type breast cancer cell lines and from matched isogenic controls. Microarray-based expression profiling was used to identify potential BRCA1-regulated transcripts. These gene targets were then validated (by in silico analysis of tumour samples) by real-time PCR and Western blot analysis. Chromatin immunoprecipitation (ChIP) assays were used to confirm recruitment of BRCA1 to specific promoters. In results, we demonstrate that functional BRCA1 represses the expression of cytokeratins 5(KRT5) and 17(KRT17) and p-Cadherin (CDH3) in HCC1937 and T47D breast cancer cell lines at both mRNA and protein level. ChIP assays demonstrate that BRCA1 is recruited to the promoters of KRT5, KRT17 and CDH3, and re-ChIP assays confirm that BRCA1 is recruited independently to form c-Myc and Sp1 complexes on the CDH3 promoter. We show that siRNA-mediated inhibition of endogenous c-Myc (and not Sp1) results in a marked increase in CDH3 expression analogous to that observed following the inhibition of endogenous BRCA1. The data provided suggest a model whereby BRCA1 and c-Myc form a repressor complex on the promoters of specific basal genes and represent a potential mechanism to explain the observed overexpression of key basal markers in BRCA1-deficient tumours.

  4. Expression of Dnmt1, demethylase, MeCP2 and methylation of tumor-related genes in human gastric cancer

    Institute of Scientific and Technical Information of China (English)

    Jing-Yuan Fang; Zhong-Hua Cheng; Ying-Xuan Chen; Rong Lu; Li Yang; Hong-Yin Zhu; Lun-Gen Lu

    2004-01-01

    AIM: To explore the effect of DNA methyltransferase,demethylase and methyl-CpG binding protein MeCP2 on the expressions and methylation of hMSH2 and protooncogene in human gastric cancer.METHODS: Paired samples of primary gastric cancer and corresponding para-cancerous, non-cancerous gastric mucosae were obtained from surgically resected specimens of 28 patients. Transcription levels of Dnmt1, mbd2, MeCP2, p16INK4A,hMSH2 and c-myc were detected by using real-time PCR or RT-PCR. Promoter methylation of p16INK4A, c-myc and hMSH2 genes was assayed by methylation-specific PCR (MSP) and sequencing (mapping). Their relationships were analyzed by Fisher's exact test using the software SPSS. RESULTS: The average mRNA level of Dnmt1 gene from cancerous tissue was higher and that of mbd2 gene from cancerous tissue was lower than that from non-cancerous tissue, respectively. mbd2 was lower in cancerous tissue than in non-cancerous tissue in 14 (50.0%) of patients but higher in 3 cases (10.7%) of non-cancerous gastric tissue (P<0.001). c-myc expression was up-regulated in cancer tissues (P<0.05). The up-regulation of mbd2 was found in all patients with hypomethylated c-myc. The transcriptional levels of p16INK4A and MeCP2 genes did not display any differencebetween gastric cancerous and matched non-cancerous tissues. There were down-regulation and hypermethylation of hMSH2 in cancer tissues, and the hypermethylation of hMSH2 coexisted with down-regulated transcription.However, the transcription level of the above genes was not associated with biological behaviours of gastric cancers.CONCLUSION: The up-regulation of proto-oncogene may be the consequence of epigenetic control of gene expression by demethylase, and mbd2 is involved in the regulation of hMSH2 expression in human gastric cancer.

  5. Association of HLA-DRB1, interleukin-6 and cyclin D1 polymorphisms with cervical cancer in the Swedish population--a candidate gene approach.

    Science.gov (United States)

    Castro, Felipe A; Haimila, Katri; Sareneva, Inna; Schmitt, Markus; Lorenzo, Justo; Kunkel, Nelli; Kumar, Rajiv; Försti, Asta; Kjellberg, Lennart; Hallmans, Göran; Lehtinen, Matti; Hemminki, Kari; Pawlita, Michael

    2009-10-15

    High-risk human papillomavirus (hrHPV) infection is the major risk factor for cervical cancer (CxCa). The role of genetic susceptibility in the disease has been suggested, but the existing data lack consistency. We conducted a nested case-control study on 973 CxCa cases and 1,763 matched controls, from two Swedish population-based cohorts to examine the association of common genetic variants with CxCa risk. Human leukocyte antigen (HLA) alleles and 24 other polymorphisms in 14 genes were selected on the basis of reported association or mechanistic plausibility with an HPV infection or cervical cancer development. Genotyping was conducted using multiplex PCR and Luminex technology. A significant association of CxCa with various polymorphisms was observed: rs1800797 in the IL-6 gene (odds ratio [OR] = 0.88, 95% confidence intervals [CI]: 0.79-0.99); rs1041981 in the LTA gene (OR = 0.87, 95% CI: 0.78-0.98), and rs9344 in the CCND1 gene (OR = 1.14, 95% CI: 1.02-1.27), for those individuals carrying the rare allele. Additionally, the alleles 0401 and 1501 of the HLA class II DRB1 locus were associated with an increased risk (OR = 1.23, 95% CI: 1.04-1.45 and OR = 1.29, 95% CI: 1.11-1.50, respectively), and allele 1301 was associated with decreased risk (OR = 0.59, 95% CI: 0.47-0.73). The effects of CCND1 and the HLA*DRB1 alleles were independent of the effect of smoking. We did not find any association of risk with polymorphisms in genes related to the innate immune system. In conclusion, our study provides evidence for genetic susceptibility to CxCa due to variations in genes involved in the immune system and in cell cycle.

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

    Science.gov (United States)

    2007-02-01

    G1 growth arrest. Improved Myc-Max Inhibitors2 Mol Cancer Ther 2007;6(9). September 2007 Growth ofMammalian Cells HL60 human promyelocytic leukemia ...Supplementary Fig. S1.7 Each compound was initially tested for its ability to inhibit the growth of the HL60 human promyelocytic leukemia cell line, which...apoptosis, and myeloid differentiation of human acute myeloid leukemia . Exp Hematol 2006;34: 1480–9. 19. Zhang H, Fan S, Prochownik EV. Distinct

  7. Identification of FGF19 as a prognostic marker and potential driver gene of lung squamous cell carcinomas in Chinese smoking patients.

    Science.gov (United States)

    Tan, Qiang; Li, Fan; Wang, Guan; Xia, Weiliang; Li, Ziming; Niu, Xiaomin; Ji, Wenxiang; Yuan, Hong; Xu, Qiang; Luo, Qingquan; Zhang, Jie; Lu, Shun

    2016-04-05

    Comprehensive genomic characterizations of lung squamous cell carcinoma (LSCC) have been performed, but the differences between smokers (S-LSCC) and never smokers (NS-LSCC) are not clear, as NS-LSCC could be considered as a different disease from S-LSCC. In this study we delineated genomic alterations in a cohort of 21 NS-LSCC and 16 S-LSCC patients, and identified common gene mutations and amplifications as previously reported. Inclusion of more NS-LSCC patients enabled us to identify unreported S-LSCC- or NS-LSCC-specific alterations. Importantly, an amplification region containing FGF19, FGF3, FGF4 and CCND1 was found five-times more frequent in S-LSCC than in NS-LSCC. Amplification of FGF19 was validated in independent LSCC samples. Furthermore, FGF19 stimulated LSCC cell growth in vitro. These data implicate FGF19 as a potential driver gene in LSCC with clinic characteristics as smoking.

  8. THE CORRELATION BETWEEN THE EXPRESSION OF MULTIDRUG RESISTANCE RELATED GENE AND CELL APOPTOSIS AND CLINICAL SIGNIFICANCE IN NON-SMALL CELL LUNG CANCER

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Objective: To explore the correlation and clinical significance between expression of MDR (multidrug resistance) related gene MRP, MDR1, C-erbB-2 and cell apoptosis in non-small cell lung cancer (NSCLC). Methods: RT-PCR, Immunohistochemistry were used to examine the expression of mRNA and protein in the MDR and apoptosis related gene. Apoptosis cells were assayed by Terminal deoxynucleotidyl transferase (TdT)- mediated biotin dUTP nick end-labeling (TUNEL). Results: The positive rates of MRP, MDR1, C-erbB-2, bc1-2, C-myc mRNA in 63 cases NSCLC were 81.0% (51/63), 38.1%(24/63), 47.6%(30/63), 65.1%(41/63), 76.2%(48/63) respectively. Their levels were higher than those of corresponding proteins (74.6%, 34.9%, 46.0%, 61.9%, 71.4%, respectively). The significant association was found between the mRNA level and the protein expression (r =+0.764, P<0.02). The C-myc expression in 2 cases adjacent and benign lung tissue were light positive, and another 3 cases were negative. The positive correlation were demonstrated between C-myc and C-erbB-2 (r=+0.547, p=0.001) as well as bcl-2 and C-erbB-2 (r =+0.486, p=0.023) in NSCLC. There is no any correlation among bcl-2, C-myc and MRP or MDR1. There exists inverse correlation between apoptotic index and bcl-2 (r = -0.587, p = 0.017), and no any correlation among apoptotic index and MRP com or MDR1 or C-erbB-2 or C-myc. The average apoptotic index were higher in the effective chemotherapy group (27.2± 2.1, 30.5± 1.8) than that in the non-effective chemotherapy group (9.4± 1.3, 12.6± 2.4) with adenocarcinoma and squamous cell carcinoma (p =0.01, p=0.004). The positive rates of bcl-2, MRP, C-erbB-2 expression in the effective chemotherapy group (31.8%, 40.9%, 22.7%, respectively) were lower than those in the non-effective chemotherapy group (77.4%, 90.3%, 67.7%, respectively) (p=0.036, p=0.012, p=0.01), but MDR1 and C-myc expression have no any significant difference (p=0.067, p=0.282). The median survival time in the patients

  9. A 6-gene signature identifies four molecular subgroups of neuroblastoma

    Directory of Open Access Journals (Sweden)

    Kogner Per

    2011-04-01

    Full Text Available Abstract Background There are currently three postulated genomic subtypes of the childhood tumour neuroblastoma (NB; Type 1, Type 2A, and Type 2B. The most aggressive forms of NB are characterized by amplification of the oncogene MYCN (MNA and low expression of the favourable marker NTRK1. Recently, mutations or high expression of the familial predisposition gene Anaplastic Lymphoma Kinase (ALK was associated to unfavourable biology of sporadic NB. Also, various other genes have been linked to NB pathogenesis. Results The present study explores subgroup discrimination by gene expression profiling using three published microarray studies on NB (47 samples. Four distinct clusters were identified by Principal Components Analysis (PCA in two separate data sets, which could be verified by an unsupervised hierarchical clustering in a third independent data set (101 NB samples using a set of 74 discriminative genes. The expression signature of six NB-associated genes ALK, BIRC5, CCND1, MYCN, NTRK1, and PHOX2B, significantly discriminated the four clusters (p ALK, BIRC5, and PHOX2B, and was significantly associated with higher tumour stage, poor outcome and poor survival compared to the Type 1-corresponding favourable group (INSS stage 4 and/or dead of disease, p Conclusions Based on expression profiling we have identified four molecular subgroups of neuroblastoma, which can be distinguished by a 6-gene signature. The fourth subgroup has not been described elsewhere, and efforts are currently made to further investigate this group's specific characteristics.

  10. Interferon-inducible IFI16, a negative regulator of cell growth, down-regulates expression of human telomerase reverse transcriptase (hTERT gene.

    Directory of Open Access Journals (Sweden)

    Lynda Li Song

    Full Text Available BACKGROUND: Increased levels of interferon (IFN-inducible IFI16 protein (encoded by the IFI16 gene located at 1q22 in human normal prostate epithelial cells and diploid fibroblasts (HDFs are associated with the onset of cellular senescence. However, the molecular mechanisms by which the IFI16 protein contributes to cellular senescence-associated cell growth arrest remain to be elucidated. Here, we report that increased levels of IFI16 protein in normal HDFs and in HeLa cells negatively regulate the expression of human telomerase reverse transcriptase (hTERT gene. METHODOLOGY/PRINCIPAL FINDINGS: We optimized conditions for real-time PCR, immunoblotting, and telomere repeat amplification protocol (TRAP assays to detect relatively low levels of hTERT mRNA, protein, and telomerase activity that are found in HDFs. Using the optimized conditions, we report that treatment of HDFs with inhibitors of cell cycle progression, such as aphidicolin or CGK1026, which resulted in reduced steady-state levels of IFI16 mRNA and protein, was associated with increases in hTERT mRNA and protein levels and telomerase activity. In contrast, knockdown of IFI16 expression in cells increased the expression of c-Myc, a positive regulator of hTERT expression. Additionally, over-expression of IFI16 protein in cells inhibited the c-Myc-mediated stimulation of the activity of hTERT-luc-reporter and reduced the steady-state levels of c-Myc and hTERT. CONCLUSIONS/SIGNIFICANCE: These data demonstrated that increased levels of IFI16 protein in HDFs down-regulate the expression of hTERT gene. Our observations will serve basis to understand how increased cellular levels of the IFI16 protein may contribute to certain aging-dependent diseases.

  11. Interferon-Inducible IFI16, a Negative Regulator of Cell Growth, Down-Regulates Expression of Human Telomerase Reverse Transcriptase (hTERT) Gene

    Science.gov (United States)

    Shen, Hui; Duan, Xin; Alimirah, Fatouma; Choubey, Divaker

    2010-01-01

    Background Increased levels of interferon (IFN)-inducible IFI16 protein (encoded by the IFI16 gene located at 1q22) in human normal prostate epithelial cells and diploid fibroblasts (HDFs) are associated with the onset of cellular senescence. However, the molecular mechanisms by which the IFI16 protein contributes to cellular senescence-associated cell growth arrest remain to be elucidated. Here, we report that increased levels of IFI16 protein in normal HDFs and in HeLa cells negatively regulate the expression of human telomerase reverse transcriptase (hTERT) gene. Methodology/Principal Findings We optimized conditions for real-time PCR, immunoblotting, and telomere repeat amplification protocol (TRAP) assays to detect relatively low levels of hTERT mRNA, protein, and telomerase activity that are found in HDFs. Using the optimized conditions, we report that treatment of HDFs with inhibitors of cell cycle progression, such as aphidicolin or CGK1026, which resulted in reduced steady-state levels of IFI16 mRNA and protein, was associated with increases in hTERT mRNA and protein levels and telomerase activity. In contrast, knockdown of IFI16 expression in cells increased the expression of c-Myc, a positive regulator of hTERT expression. Additionally, over-expression of IFI16 protein in cells inhibited the c-Myc-mediated stimulation of the activity of hTERT-luc-reporter and reduced the steady-state levels of c-Myc and hTERT. Conclusions/Significance These data demonstrated that increased levels of IFI16 protein in HDFs down-regulate the expression of hTERT gene. Our observations will serve basis to understand how increased cellular levels of the IFI16 protein may contribute to certain aging-dependent diseases. PMID:20052289

  12. Expression of Senescence-Associated microRNAs and Target Genes in Cellular Aging and Modulation by Tocotrienol-Rich Fraction

    Directory of Open Access Journals (Sweden)

    Sharon Gwee Sian Khee

    2014-01-01

    Full Text Available Emerging evidences highlight the implication of microRNAs as a posttranscriptional regulator in aging. Several senescence-associated microRNAs (SA-miRNAs are found to be differentially expressed during cellular senescence. However, the role of dietary compounds on SA-miRNAs remains elusive. This study aimed to elucidate the modulatory role of tocotrienol-rich fraction (TRF on SA-miRNAs (miR-20a, miR-24, miR-34a, miR-106a, and miR-449a and established target genes of miR-34a (CCND1, CDK4, and SIRT1 during replicative senescence of human diploid fibroblasts (HDFs. Primary cultures of HDFs at young and senescent were incubated with TRF at 0.5 mg/mL. Taqman microRNA assay showed significant upregulation of miR-24 and miR-34a and downregulation of miR-20a and miR-449a in senescent HDFs (P<0.05. TRF reduced miR-34a expression in senescent HDFs and increased miR-20a expression in young HDFs and increased miR-449a expression in both young and senescent HDFs. Our results also demonstrated that ectopic expression of miR-34a reduced the expression of CDK4 significantly (P<0.05. TRF inhibited miR-34a expression thus relieved its inhibition on CDK4 gene expression. No significant change was observed on the expression of CCND1, SIRT1, and miR-34a upstream transcriptional regulator, TP53. In conclusion tocotrienol-rich fraction prevented cellular senescence of human diploid fibroblasts via modulation of SA-miRNAs and target genes expression.

  13. Expression of nuclear factor-kappa B and target genes in gastric precancerous lesions and adenocarcinoma:Association with Helicobactor pylori cagA (+) infection

    Institute of Scientific and Technical Information of China (English)

    Gui-Fang Yang; Chang-Sheng Deng; Yong-Yan Xiong; Ling-Ling Gong; Bi-Cheng Wang; Jun Luo

    2004-01-01

    AIM: To examine the expression of nuclear factor kappaB (NF-κB) and its target genes in intestinal metaplasia (IN),dysplasia (DYS) and gastric carcinoma (GC) infected with Helicobacter pylori(H pylori) and to investigate the mechanism underlying H pylori cytotoxin associated gene A (cag A) infection leading to gastric adenocarcinoma.METHODS: Expressions of NF-κB/p65 and its target genes:c-myc, cyclinD1 and bcl-xl were immunohistochemically examined in 289 cases of gastric biopsy and resection specimens from patients with IM, DYS and GC infected with H pylori. H pylori in the above mentioned tissues was detected by Warthin-Starry stain and rapid urease tests.IgG antibody to cagA in sera of the patients was measured by ELISA.RESULTS: The positive rates of NF-κB/p65 were significantly higher in groups with cagA of IMI-Ⅱ(28/33), IM Ⅲ(48/52),DYSI(27/31), DYS Ⅱ-Ⅲ(28/32), GC(35/40) than in groups without cagA of IMI-Ⅱ(4/17), IMIII(3/20), DYSI(3/20),DYSII-Ⅲ(6/21), GC(10/23). The expressions of c-myc,cyclinD1, and bcl-xl were significantly higher in groups with cagA of IM Ⅲ(47/52, 49/52, 46/52), DYSII-Ⅲ(29/32, 26/32,25/32) than in groups without cagA of IM Ⅲ(8/20, 7/20,5/20), DYSII-Ⅲ(10/21, 8/21,3/21), which were in conformity with the expression of NF-κB in IM Ⅲ, and DYSII-Ⅲ. A significantly higher expression level of NF-κB/p65, c-myc,cyclinD1 and bcl-xl was detected in intestinal type GC(27/28,18/28, 22/28, 24/28) than in diffuse type GC(8/12, 3/12,3/12, 6/12), respectively.CONCLUSION: There may be two different molecular mechanisms in the occurrence of intestinal and diffuse type gastric carcinomas. Intestinal type gastric carcinoma is strongly associated with high expression of c-myc, cyclinD1 and bcl-xl through NF-κB/p65 activated by H pylori cagA.Inhibiting the activity of NF-κB is an effective and promising way to prevent intestinal type gastric carcinoma.

  14. Ets2 binding site single nucleotide polymorphism at the hTERT gene promoter--effect on telomerase expression and telomere length maintenance in non-small cell lung cancer.

    Science.gov (United States)

    Hsu, Chung-Ping; Hsu, Nan-Yuan; Lee, Li-Wen; Ko, Jiunn-Liang

    2006-07-01

    The aim of this study was to elucidate the occurrence of DNA sequence changes in the promoter region of hTERT gene, and its effect on telomerase expression and telomere length maintenance in non-small cell lung cancer (NSCLC). Between January 2002 and December 2003, 66 NSCLC patients were studied. The expression of hTERT, telomerase activity (TA), and c-Myc were examined, and the terminal restriction fragment length (TRFL) was measured. A t/n-TRFLR was obtained by dividing the TRFL of the tumour tissue by TRFL of the paired normal tissue. PCR products were sequenced and compared with known hTERT gene promoter sequence for a length of 716 bp upstream of the transcription starting code. The changes of any known sequence and/or c-Myc expression with their impact on telomerase activity and TRFL maintenance were measured. Positive hTERT, TA and c-Myc expression was observed in 43 (65.2%), 39 (59.1%) and 59 (89.4%) of the tumour tissue samples, respectively. Except for one patient who had C/C (in normal tissue) homozygotes to T/C (in tumour tissue) heterozygotes point mutation, a novel single nucleotide polymorphism (SNP) -245 kb upstream (Ets2 binding site) of the hTERT gene was observed in all normal and tumour tissues, including C/C in 9, T/C in 35, and T/T in 22 of the tumour tissues. The TA of C/C homozygotes was lower than that of T/T homozygotes (P=0.0331), while the t/n-TRFLR of C/C homozygotes was higher than that of T/T homozygotes (P=0.0621). The latter was even more obvious when c-Myc were positive (P=0.0185). Our data shows that T/T homozygotes have a lower t/n-TRFLR, but a stronger TA expression, suggesting that the studied Ets2 binding site is a positive regulator of hTERT gene. SNP may interfere with Ets2 binding and lower TA expression in T/C heterozygotes and C/C homozygotes.

  15. Effect of hrHPV infection on anti-apoptotic gene and pro-apoptotic gene expression in cervical cancer tissue

    Institute of Scientific and Technical Information of China (English)

    Min-Er Tang

    2016-01-01

    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 pro-apoptotic 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.

  16. Undifferentiated embryonic cell transcription factor 1 regulates ESC chromatin organization and gene expression

    DEFF Research Database (Denmark)

    Kooistra, Susanne M; van den Boom, Vincent; Thummer, Rajkumar P;

    2010-01-01

    cell chromatin structure. Using chromatin immunoprecipitation-on-chip analysis, we identified >1,700 UTF1 target genes that significantly overlap with previously identified Nanog, Oct4, Klf-4, c-Myc, and Rex1 targets. Gene expression profiling showed that UTF1 knock down results in increased expression......Previous reports showed that embryonic stem (ES) cells contain hyperdynamic and globally transcribed chromatin-properties that are important for ES cell pluripotency and differentiation. Here, we demonstrate a role for undifferentiated embryonic cell transcription factor 1 (UTF1) in regulating ES...... to dimethyl sulfoxide (DMSO) or after LIF withdrawal and display increased colony formation. UTF1 KD ES cells display extensive chromatin decondensation, reflected by a dramatic increase in nucleosome release on micrococcal nuclease (MNase) treatment and enhanced MNase sensitivity of UTF1 target genes in UTF1...

  17. Biological impact of hepatitis B virus X-hepatitis C virus core fusion gene on

    Institute of Scientific and Technical Information of China (English)

    Ma Zhen; Qin-Hai Shen; Guo-Min Chen; Da-Zhi Zhang

    2008-01-01

    AIM: To investigate the biological impact of hepatitis B virus X- hepatitis C virus core (HBV X-HCV C) fusion gene on hepatoma cells.METHODS: The recombinant adenoviruses AdXC,Ad-X and Ad-C expressing HBV X-HCV C fusion gene,HBVX gene and HCV C gene were constructed,respectively.Hepatoma cells were infected with different recombinant adenoviruses.MTT,colonyforming experiment,FCM,TUNEL assay were performed to observe the biological impact of the HBV X-HCV C fusion gene on liver cells.RESULTS: MTT showed that the Ad-XC group cells grew faster than the other group cells.Colony-forming experiment showed that the colony-forming rate for the Ad-XC group cells was significantly higher than that for the other group cells.FCM analysis showed that Ad-XC/Ad-X/Ad-C infection enhanced the progression of GIS phase in the HepG2 cell cycle.The apoptosis index of the Ad-XC,Ad-X,Ad-C group cells was significantly lower than that of the AdO and control group cells.Semi-quantitative RT-PCR showed that the expression level of c-myc was the highest in AdXC infected cells.Tumor formation was found at the injected site of mice inoculated with Ad-XC-infected LO2 cells,but not in control mice.CONCLUSION: Ad-XC,Ad-X and Ad-C facilitate the proliferation activity of HepG2 cells and inhibit their apoptosis in vitro.The effect of Ad-XC is significantly stronger than that of Ad-X and Ad-C.Up-regulation of c-myc may be one of the mechanisms underlying the synergism of HBVX and HCV C genes on hepatocarcinogenesis in athymic nude mice.

  18. Molecular signatures of trauma-hemorrhagic shock-induced lung injury: hemorrhage- and injury-associated genes.

    Science.gov (United States)

    Feinman, Rena; Deitch, Edwin A; Aris, Virginie; Chu, Hung B; Abungu, Billy; Caputo, Francis J; Galante, Anthony; Xu, DaZhong; Lu, Qi; Colorado, Iriana; Streck, Deanna; Dermody, James; Soteropoulos, Patricia

    2007-09-01

    The etiology of trauma-hemorrhagic shock (T/HS)-induced acute lung injury has been difficult to elucidate because of, at least in part, the inability of in vivo studies to separate the noninjurious pulmonary effects of trauma-hemorrhage from the tissue-injurious ones. To circumvent this in vivo limitation, we used a model of T/HS in which T/HS lung injury was abrogated by dividing the mesenteric lymph duct. In this way, it was possible to separate the pulmonary injurious response from the noninjurious systemic response to T/HS by comparing the pulmonary molecular responses of rats subjected to T/HS, which did and did not develop lung injury, with those of nonshocked rats. Using high-density oligonucleotide arrays and treatment group comparisons of whole lung tissue collected at 3 h after the end of the shock or sham-shock period, 139 of 8,799 assessed genes were identified by significant analysis of microarrays. Hemorrhage without the secondary effects of lung injury modulated the expression of 21 genes such as interleukin 1beta, metallothionein-2, and myeloctomatosis oncogene (c-myc). In response to injury, 42 genes were identified to be differentially expressed. Upregulated genes included the L1 retroposon and guanine deaminase, whereas downregulated genes included catalase and superoxide dismutase 1. Real-time polymerase chain reaction confirmed the differential expression for selected genes. PathwayAssist analysis identified interleukin 1beta as a central regulator of two subpathways of stress response-related genes (c-myc and superoxide dismutase 1/catalase) as well as several unrelated genes such as lipoprotein lipase. Our model system provided a unique opportunity to distinguish the molecular changes associated with T/HS-induced acute lung injury from the systemic molecular response to T/HS.

  19. Effect of probiotic fermented milk and chlorophyllin on gene expressions and genotoxicity during AFB₁-induced hepatocellular carcinoma.

    Science.gov (United States)

    Kumar, Manoj; Verma, Vinod; Nagpal, Ravinder; Kumar, Ashok; Gautam, Sanjeev K; Behare, Pradip V; Grover, Chand R; Aggarwal, Praveen K

    2011-12-15

    The aim of this study was to investigate the chemopreventive effect of probiotic fermented milk and chlorophyllin on aflatoxin B₁ (AFB₁) induced hepatocellular carcinoma. In vivo trials were conducted on 200 Wistar rats allocated to eight groups. Rats in the positive control group were given intraperitoneal injection of aflatoxin B₁ at 450 μg/kg body weight twice a week for 6 weeks. The rats were sacrificed and dissected at 25th week of the experiment, and comet assay was carried out in hepatic cells to assess the genotoxicity or DNA damage. The tumour incidence was decreased by approximately one-third than AFB₁ control group. The expression of c-myc bax, bcl-2, cyclin D1, p53 and rasp-21 genes was also studied. A significant (Pchlorophyllin group as compared to aflatoxin B₁ control group. The c-myc, bcl-2, cyclin D1 and rasp-21 level was found to be highest in AFB₁ control group as compared to the treatment group. The results advocate the enhanced protective potential of probiotic fermented milk and chlorophyllin against AFB₁-induced molecular alterations in hepatic cells during carcinogenesis.

  20. Extracellular simian virus 40 induces an ERK/MAP kinase-independent signalling pathway that activates primary response genes and promotes virus entry.

    Science.gov (United States)

    Dangoria, N S; Breau, W C; Anderson, H A; Cishek, D M; Norkin, L C

    1996-09-01

    Simian virus 40 (SV40) binding to growth-arrested cells activated an intracellular signalling pathway that induced the up-regulation of the primary response genes c-myc, c-jun and c-sis within 30 min and of JE within 90 min. The up-regulation of the primary response genes occurred in the presence of cycloheximide and when UV-inactivated SV40 was adsorbed to cells. SV40 binding did not activate Raf or mitogen-activated protein kinase (MAP/ERK1), or mobilize intracellular Ca2+. The SV40-induced up-regulation of c-myc and c-jun was blocked by the tyrosine kinase inhibitor, genistein, and by the protein kinase C (PKC) inhibitor, calphostin C, but not by expression of the MAP kinase-specific phosphatase, MKP-1. These results suggest that the SV40-induced signalling pathway includes the activities of a tyrosine kinase and a Ca(2+)-independent isoform of PKC, but not of Raf or MAP kinase. Finally, SV40 infectious entry into cells was specifically and reversibly blocked by genistein.

  1. Gene expression array analyses predict increased proto-oncogene expression in MMTV induced mammary tumors.

    Science.gov (United States)

    Popken-Harris, Pamela; Kirchhof, Nicole; Harrison, Ben; Harris, Lester F

    2006-08-01

    Exogenous infection by milk-borne mouse mammary tumor viruses (MMTV) typically induce mouse mammary tumors in genetically susceptible mice at a rate of 90-95% by 1 year of age. In contrast to other transforming retroviruses, MMTV acts as an insertional mutagen and under the influence of steroid hormones induces oncogenic transformation after insertion into the host genome. As these events correspond with increases in adjacent proto-oncogene transcription, we used expression array profiling to determine which commonly associated MMTV insertion site proto-oncogenes were transcriptionally active in MMTV induced mouse mammary tumors. To verify our gene expression array results we developed real-time quantitative RT-PCR assays for the common MMTV insertion site genes found in RIII/Sa mice (int-1/wnt-1, int-2/fgf-3, int-3/Notch 4, and fgf8/AIGF) as well as two genes that were consistently up regulated (CCND1, and MAT-8) and two genes that were consistently down regulated (FN1 and MAT-8) in the MMTV induced tumors as compared to normal mammary gland. Finally, each tumor was also examined histopathologically. Our expression array findings support a model whereby just one or a few common MMTV insertions into the host genome sets up a dominant cascade of events that leave a characteristic molecular signature.

  2. Relationship between helicobacter pylori infection and the expressions of p53, ras, c-myc gene in gastric cancer and precancerous lesions%Hp感染与胃癌和癌前病变中p53、ras、c-myc基因表达的关系

    Institute of Scientific and Technical Information of China (English)

    陈洋; 李舒

    2009-01-01

    目的 研究幽门螺杆菌(Hp)感染与胃癌(GC)和癌前病变中p53、ras、c-myc基因表达的关系,以探讨其致病机制.方法 用美兰和W-S特殊染色方法确定Hp感染,免疫组化SP法检测p53、ras、c-myc基因的表达.结果 慢性萎缩性胃炎(CAG)、肠化生(IM)、异型增生(DYS)、GC的Hp感染率均高于慢性浅表性胃炎(CSG)(P均<0.05);p53、ras、c-myc基因在GC、DYS中的表达均高于CAG(P均<0.05),p53、ras基因在IM中的表达均高于CAG(P<0.05);IM中Hp阳性者的p53阳性表达率高于Hp阴性者(P<0.05),DYS、GC中Hp阳性者p53、ras、c-myc的表达率高于Hp阴性者(P均<0.05).结论 Hp感染可能通过调节p53、ras、c-myc基因的表达而促进GC的发生.

  3. 幽门螺杆菌感染和端粒酶活性以及c-myc、p16基因的表达在胃黏膜癌变中的相关性研究%Helicobacter pylori Infection, Telomerase Activity and the Expression of c-myc and p16 Genes in the Process of Gastric Tumorigenesis

    Institute of Scientific and Technical Information of China (English)

    顾艳宏; 赵志泉; 张国新; 张红杰; 郝波

    2003-01-01

    背景:幽门螺杆菌(H.pylori)是胃癌的主要致病因子,H. pylori、端粒酶和肿瘤相关基因的关系在胃黏膜癌变发生过程中研究很少.目的:观察H.pylori感染和端粒酶活性以及c-myc、p16基因在胃癌中的关系.方法:通过胃镜活检和外科手术获取171例胃组织标本,快速尿素酶试验和H.pylori培养确定有无H.pylori感染;酶联免疫法检测H.pylori感染患者的血清CagA-IgG水平;聚合酶链反应-酶联免疫吸附测定(PCR-ELISA)法检测端粒酶活性;免疫组化法检测c-myc、p16基因的表达.结果:胃癌(GC)组端粒酶表达率显著高于其他各组(P<0.01);慢性萎缩性胃炎(CAG)伴中、重度肠化(IM)组端粒酶和c-myc表达率显著高于CAG伴轻度IM组(P<0.05);而慢性浅表性胃炎(CSG)和CAG伴轻度IM组p16表达率显著高于CAG伴中、重度IM、异型增生(Dys)和GC组(P<0.05).在CAG伴轻、中、重度IM组中,H. pylori阳性组端粒酶活性比阴性组高;无论有无H. pylori感染,胃癌组端粒酶活性都非常高.在CAG伴中、重度IM、Dys和GC组中,H. pylori阳性亚组c-myc表达显著高于阴性亚组(P<0.01),而在CAG伴中、重度IM和Dys组中,H. pylori阳性亚组p16基因表达显著低于阴性亚组(P<0.01).结论:H. pylori感染很可能主要通过c-myc基因的激活和p16基因的失活以及其他基因的变化来诱导CAG伴中、重度IM组织中的端粒酶活性来启动胃癌的发生,这也许是H. pylori致胃癌的作用机制之一.

  4. 莫索尼定对自发性高血压大鼠左室肥厚及c-myc基因表达的影响%Effects of moxonidine hydrochloride on left ventricular hypertrophy and c-myc gene expression in spontaneously hypertensive rats

    Institute of Scientific and Technical Information of China (English)

    张蓬勃; 牛小麟; 常丹

    2003-01-01

    目的研究国产盐酸莫索尼定(Mox)对自发性高血压大鼠(SHR)左室肥厚的逆转作用及其可能机制.方法 20周龄的雄性自发性高血压大鼠30只随机分为①Mox+SHR组,②Cap+SHR组,③SHR组,每组10 只.另设性别、周龄相配的SD大鼠10只为正常对照组(NC组).观察期末,测量左心室重/体重(LVW/BW)、左室胶原分数(CVF)、标准化血管周胶原面积(PVCA)、肌间动脉中膜厚度(AMT)及左室组织c-myc基因表达的变化.结果 Mox+SHR组不仅LVW/BW明显低于SHR组[(3.46±0.13)mg*g-1 vs(3.96±0.18)mg*g-1,P<0.01],CVF低于SHR组[(0.086±0.018 )vs(0.046±0.015),P<0.01],PVCA少于SHR组[(0.69±0.11) vs(1.34±0.29),P<0.01],AMT薄于SHR组[(7.97±0.73)μm vs(11.91±1.16)μm, P<0.01],而且c-myc表达量也低于SHR组[(0.74±0.16)A vs(1.24±0.21)A,P<0.01].结论盐酸莫索尼定能够逆转自发性高血压大鼠的左室肥厚,对c-myc基因表达的减少可能是其作用机制.

  5. Effect of oxymatrine on cell proliferation and c-fos, c-myc gene expression in vascular smooth muscle cells of rabbit%氧化苦参碱对兔血管平滑肌细胞增殖及c-fos和c-myc基因表达的影响

    Institute of Scientific and Technical Information of China (English)

    郭宏林; 洪燕英

    2013-01-01

    目的 观察氧化苦参碱(OMT)对兔血管平滑肌细胞(VSMC)增殖的影响.方法 采用高脂诱导兔动脉粥样硬化(AS)模型,体外培养兔主动脉VSMC,以3H-TdR掺入、流式细胞分析和cDNA探针原位杂交方法观察OMT对VSMC增殖和c-fos、c-myc基因表达的影响.结果 OMT可显著抑制VSMC增殖,使处于G1期与G2 +M的细胞显著增多,同时抑制VSMC中c-fos和c-myc基因的表达.结论 OMT对VSMC增殖有显著抑制作用,其机制可能与抑制VSMC中c-fos和c-myc基因表达有关.

  6. Effect of sulfur dioxide on expression of proto-oncogenes and tumor suppressor genes from rats.

    Science.gov (United States)

    Bai, Juli; Meng, Ziqiang

    2010-06-01

    Sulfur dioxide (SO(2)) is a ubiquitous air pollutant that is present in low concentrations in the urban air, and in higher concentrations in the working environment. In the present study, male Wistar rats were housed in exposure chambers and treated with 14.00 +/- 1.01, 28.00 +/- 1.77 and 56.00 +/- 3.44 mg m(-3) SO(2) for 6 h/day for 7 days, while control group was exposed to filtered air in the same condition. The mRNA and protein levels of proto-oncogenes (c-fos, c-jun, c-myc, and Ki-ras) and tumor suppressor genes (p53, Rb, and p16) were analyzed in lungs using a real-time reverse transcription-polymerase chain reaction (real-time RT-PCR) assay and Western blot analysis. The results showed that mRNA and protein levels of c-fos, c-jun, c-myc, Ki-ras, and p53 in lungs were increased in a dose-dependent manner, while mRNA and protein levels of Rb and p16 were decreased in lungs of rats after SO(2) inhalation. These results lead to a conclusion that SO(2) exposure could activate expressions of proto-oncogenes and suppress expressions of tumor suppressor genes, which might relate to the molecular mechanism of cocarcinogenic properties and potential carcinogenic effects of SO(2). According to previous studies, the results also indicated that promoter genes of apoptosis and tumor suppressor genes could produce apoptotic signals to antagonize the growth signals that arise from oncogenes. Understanding its molecular controls will benefit development of treatments for many diseases.

  7. ShRNA-mediated gene silencing of β-catenin inhibits growth of human colon cancer cells

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    AIM: To observe the gene silencing mediated by the specific shRNA targeted against β-catenin and its effect on cell proliferation and cycle distribution in the human colon cancer cell line Colo205.METHODS: Two shRNA plasmid vectors against β-catenin were constructed and transfected into Colo205 cells with LipofectamineTM2000. The down-regulations of β-catenin, c-myc and cyclinD1 expressions were detected by RT-PCR and western blot analysis. The cell proliferation inhibitions were determined by MTT assay and soft agar colony formation assay. The effect of these two β-catenin shRNAs on cell cycle distribution and apoptosis was examined by flow cytometry.RESULTS: These two shRNA vectors targeted against β-catenin efficiently suppressed the expression of β-catenin and its down stream genes, c-myc and cyclinD1. The expression inhibition rates were around 40%-50% either at the mRNA or at the protein level.The shRNA-mediated gene silencing of β-catenin resulted in significant inhibition of cell growth both on the culture plates and in the soft agar. Moreover, the cancer cells showed significant G0/G1 arrest and increased apoptosis at 72 h post transfection due to gene silencing.CONCLUSION: These specific shRNAs targeted against β-catenin could have a gene silencing effect and block the WNT signaling pathway. They could inhibit cell growth, increase apoptosis, and induce cell cycle arrest in Colo205 cells. ShRNA interference against β-catenin is of potential value in gene therapy of colon cancer.

  8. Epigenetic modification regulates both expression of tumor-associated genes and cell cycle progressing in human colon cancer cell lines:Colo-320 and SW1116

    Institute of Scientific and Technical Information of China (English)

    Jing Yuan FANG; Ying Xuan CHEN; Juan LU; Rong LU; Li YANG; Hong Yin ZHU; Wei Qi GU; Lun Gen LU

    2004-01-01

    The aim of this study is to assess the effects of DNA methylation and histone acetylation, alone or in combination, on the expression of several tumor-associated genes and cell cycle progression in two established human colon cancer cell lines: Colo-320 and SW1116. Treatments with 5-aza-2'-deoxycytidine (5-aza-dC) and trichostatin A, alone or in combination, were applied respectively. The methylation status of the CDKN2A promoter was determined by methylation-specific PCR, and the acetylated status of the histones associated with the p21wAF1 and CDKN2A genes was examined by chromatin immunoprecipitation. The expression of the CDKN2A, p21WAF1, p53, p73, APC, c-myc, c-Ki-ras and survivin genes was detected by real-time RT-PCR and RT-PCR. The cell cycle profile was established by flow cytometry.We found that along with the demethylation of the CDKN2A gene promoter in both cell lines induced by 5-aza-dC alone or in combination with TSA, the expression of both CDKN2A and APC genes increased. The treatment of TSA or sodium butyrate up-regulated the transcription of p21 WAF1 significantly by inducing the acetylation of histones H4 and H3, but failed to alter the acetylation level of CDKN2A-associated histones. No changes in transcription of p53, p73,c-myc, c-Ki-ras and survivin genes were observed. In addition, TSA or sodium butyrate was shown to arrest cells at the G1 phase. However, 5-aza-dC was not able to affect the cell cycle progression. In conclusion, regulation by epigenetic modification of the transcription of tumor-associated genes and the cell cycle progression in both human colon cancer cell lines Colo-320 and SW1116 is gene-specific.

  9. A 6-gene signature identifies four molecular subgroups of neuroblastoma

    LENUS (Irish Health Repository)

    Abel, Frida

    2011-04-14

    Abstract Background There are currently three postulated genomic subtypes of the childhood tumour neuroblastoma (NB); Type 1, Type 2A, and Type 2B. The most aggressive forms of NB are characterized by amplification of the oncogene MYCN (MNA) and low expression of the favourable marker NTRK1. Recently, mutations or high expression of the familial predisposition gene Anaplastic Lymphoma Kinase (ALK) was associated to unfavourable biology of sporadic NB. Also, various other genes have been linked to NB pathogenesis. Results The present study explores subgroup discrimination by gene expression profiling using three published microarray studies on NB (47 samples). Four distinct clusters were identified by Principal Components Analysis (PCA) in two separate data sets, which could be verified by an unsupervised hierarchical clustering in a third independent data set (101 NB samples) using a set of 74 discriminative genes. The expression signature of six NB-associated genes ALK, BIRC5, CCND1, MYCN, NTRK1, and PHOX2B, significantly discriminated the four clusters (p < 0.05, one-way ANOVA test). PCA clusters p1, p2, and p3 were found to correspond well to the postulated subtypes 1, 2A, and 2B, respectively. Remarkably, a fourth novel cluster was detected in all three independent data sets. This cluster comprised mainly 11q-deleted MNA-negative tumours with low expression of ALK, BIRC5, and PHOX2B, and was significantly associated with higher tumour stage, poor outcome and poor survival compared to the Type 1-corresponding favourable group (INSS stage 4 and\\/or dead of disease, p < 0.05, Fisher\\'s exact test). Conclusions Based on expression profiling we have identified four molecular subgroups of neuroblastoma, which can be distinguished by a 6-gene signature. The fourth subgroup has not been described elsewhere, and efforts are currently made to further investigate this group\\'s specific characteristics.

  10. 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.

  11. Differential gene regulation by the SRC family of coactivators

    Institute of Scientific and Technical Information of China (English)

    HuaZhang; XiaYi; Xiaojingsun; NaYin; BinShi; HuijianWu; DanWang; GeWu; YongfengShang

    2005-01-01

    SRCs (steroid receptor coactivatorsl are required for nuclear receptor-mediated transcription and are also implicated in the transcription initiation by other transcription factors, such as STATs and NFKB. Despite phenotypic manifestations in gene knockout mice for SRC-1, GRIP1, and AIB1 of the SRC (Steroid Receptor Coactivator) family indicating their differential roles in animal physiology, there is no clear evidence, at the molecular level, to support a functional specificity for these proteins. We demonstrated in this report that two species of SRC coactivators, either as AIBI:GRIP1 or as AIBI:SRC-1 are recruited, possibly through heterodimerization, on the promoter of genes that contain a classical hormone responsive element (HRE). In contrast, on non-HRE-containing gene promoters, on which steroid receptors bind indirectly, either GRIP1 orSRC-1 is recruited as a monomer, depending on the cellular abundance of the protein. Typically, non-HRE-containing genes are early genes activated by steroid receptors, whereas HRE-containing genes are activated later. Our results also showed that SRC proteins contribute to the temporal regulation of gene transcription. In addition, our experiments revealed a positive correlation between AIB1/c-myc overexpression in ER+ breast carcinoma samples, suggesting a possible mechanism for AIB1/n breast cancer carcinogenesis.

  12. [The effects of stathmin on cell proliferation and tumor-related genes expressions in HCCLM3 cells].

    Science.gov (United States)

    Gan, Lin; Li, Juan; Guo, Kun; Li, Yan; Shu, Hong; Wang, Li; Song, Jie; Liu, Yin-Kun

    2011-08-01

    To explore the biological function and possible underlying mechanism of stathmin gene during hepatocarcinogenesis. Three pairs of chemically synthesized small interfering RNA (siRNA) targeting on stathmin were transfected into HCCLM3 by LipofectamineTM 2000. After confirming the interfering effects of stathmin siRNAs through reverse transcription PCR and Western blotting, the HCCLM3 cells proliferation and apoptosis were detected by cell count kit-8 (CCK-8) and flow cytometry analysis, and the expressions of tumor-related genes (c-myc, c-fos, p53, etc) were observed by real-time PCR. Stathmin expression was effectively inhibited up to 90% by stathmin silencing in HCCLM3 cells (P is less than to 0.05) . By using CCK8 assay, it was shown that HCCLM3 cells proliferation were obviously depressed by 13.04%+/-0.10%, 28.10%+/-0.41% and 37.36%+/-2.15% at the time point of 24 h, 48 h and 72 h with the comparison to Mock group (F = 4.21, P is less than to 0.05). The results of flow cytometry demonstrated that the percentage of apoptotic cells was increased to 25.11%+/-1.62% in RNAi group, compared with 9.20 %+/-0.64 % in Mock group (F = 44.67, P is less than to 0.01). The results of real-time PCR showed that oncogenes c-myc and c-fos expressions were repressed, proliferation-associated gene ki-67 was down-regulated, and apoptosis-promoting gene caspase-3, bax and p53 were induced (P is less than to 0.05). Stathmin may promote cell proliferation, inhibit cell apoptosis and induce malignant transformation of hepatocytes by regulating some tumor-related genes expressions.

  13. Activation-Induced Cytidine Deaminase Contributes to Pancreatic Tumorigenesis by Inducing Tumor-Related Gene Mutations.

    Science.gov (United States)

    Sawai, Yugo; Kodama, Yuzo; Shimizu, Takahiro; Ota, Yuji; Maruno, Takahisa; Eso, Yuji; Kurita, Akira; Shiokawa, Masahiro; Tsuji, Yoshihisa; Uza, Norimitsu; Matsumoto, Yuko; Masui, Toshihiko; Uemoto, Shinji; Marusawa, Hiroyuki; Chiba, Tsutomu

    2015-08-15

    Pancreatic ductal adenocarcinoma (PDAC) develops via an accumulation of various gene mutations. The mechanism underlying the mutations in PDAC development, however, is not fully understood. Recent insight into the close association between the mutation pattern of various cancers and specific mutagens led us to investigate the possible involvement of activation-induced cytidine deaminase (AID), a DNA editing enzyme, in pancreatic tumorigenesis. Our immunohistochemical findings revealed AID protein expression in human acinar ductal metaplasia, pancreatic intraepithelial neoplasia, and PDAC. Both the amount and intensity of the AID protein expression increased with the progression from precancerous to cancerous lesions in human PDAC tissues. To further assess the significance of ectopic epithelial AID expression in pancreatic tumorigenesis, we analyzed the phenotype of AID transgenic (AID Tg) mice. Consistent with our hypothesis that AID is involved in the mechanism of the mutations underlying pancreatic tumorigenesis, we found precancerous lesions developing in the pancreas of AID Tg mice. Using deep sequencing, we also detected Kras and c-Myc mutations in our analysis of the whole pancreas of AID Tg mice. In addition, Sanger sequencing confirmed the presence of Kras, c-Myc, and Smad4 mutations, with the typical mutational footprint of AID in precancerous lesions in AID Tg mice separated by laser capture microdissection. Taken together, our findings suggest that AID contributes to the development of pancreatic precancerous lesions by inducing tumor-related gene mutations. Our new mouse model without intentional manipulation of specific tumor-related genes provides a powerful system for analyzing the mutations involved in PDAC.

  14. Mel-18 gene and neoplasms%Mel-18基因与肿瘤

    Institute of Scientific and Technical Information of China (English)

    许学宗; 曹京燕; 于雁

    2013-01-01

    黑色素瘤核蛋白-18(Mel-18)基因是多梳基因(PcG)家族核心成员之一,在胚胎形成、细胞生长和增殖、干细胞自我更新的调节中发挥重要作用.Mel-18基因表达异常与人类肿瘤的发生、发展过程有关.作为肿瘤抑制基因,Mel-18基因通过对B淋巴瘤Mo-MLV插入区域1(Bmi-1)和髓细胞癌基因(c-myc)的转录抑制而抑制肿瘤增长.Mel-18表达在许多肿瘤细胞的转录水平和翻译水平减少,其中包括乳腺癌、前列腺癌和胃癌等肿瘤,有望成为一种新的肿瘤预后标志物.%Mel-18 gene is one of the core members of the PcG (polycomb group) family,which plays an important role in embryogenesis,cell growth and proliferation and self-renewal of stem cells.Mel-18 gene expressing abnormally has been related to human tumorigenesis,development process.Mel-18 serves as a tumor suppressor gene and inhibits tumor growth through transcriptional repression of Bmi-1 and c-myc.Mel-18 expression is decreased at transcriptional and translational levels in most human cancers including breast cancer,prostate cancer,and gastric cancer and other tumors.Mel-18 is expected to become a prognostic marker for human cancers.

  15. Gene

    Data.gov (United States)

    U.S. Department of Health & Human Services — Gene integrates information from a wide range of species. A record may include nomenclature, Reference Sequences (RefSeqs), maps, pathways, variations, phenotypes,...

  16. Reversible regulation of cell cycle-related genes by epigallocatechin gallate for hibernation of neonatal human tarsal fibroblasts.

    Science.gov (United States)

    Bae, Jung Yoon; Kanamune, Jun; Han, Dong-Wook; Matsumura, Kazuaki; Hyon, Suong-Hyu

    2009-01-01

    We investigated the hibernation effect of epigallocatechin-3-O-gallate (EGCG) on neonatal human tarsal fibroblasts (nHTFs) by analyzing the expression of cell cycle-related genes. EGCG application to culture media moderately inhibited the growth of nHTFs, and the removal of EGCG from culture media led to complete recovery of cell growth. EGCG resulted in a slight decrease in the cell population of the S and G(2)/M phases of cell cycle with concomitant increase in that of the G(0)/G(1) phase, but this cell cycle profile was restored to the initial level after EGCG removal. The expression of cyclin D1 (CCND1), CCNE2, CCN-dependent kinase 6 (CDK6), and CDK2 was restored, whereas that of CCNA, CCNB1, and CDK1 was irreversibly attenuated. The expression of a substantial number of genes analyzed by cDNA microarray was affected by EGCG application, and these affected expression levels were restored to the normal levels after EGCG removal. We also found the incorporation of FITC-EGCG into the cytosol of nHTFs and its further nuclear translocation, which might lead to the regulation of the exogenous signals directed to genes for cellular responses including proliferation and cell cycle progression. These results suggest that EGCG temporarily affects not only genes related to the cell cycle but also various other cellular functions.

  17. Cyclin D1 gene polymorphism as a risk factor for squamous cell carcinoma of the upper aerodigestive system in non-alcoholics

    DEFF Research Database (Denmark)

    Nishimoto, Ines Nobuko; Pinheiro, Nidia Alice; Rogatto, Silvia Regina;

    2004-01-01

    Squamous cell carcinoma of the upper aerodigestive tract (UADT) is associated with environmental factors, especially tobacco and alcohol consumption. Genetic factors, including cyclin D1 (CCND1) polymorphism have been suggested to play an important role in tumorigenesis and progression of UADT...... in non-alcoholics. However, further epidemiological studies are needed to establish the exact role of CCND1 polymorphism and the development of UADT cancers....

  18. Predictive gene signatures: molecular markers distinguishing colon adenomatous polyp and carcinoma.

    Science.gov (United States)

    Drew, Janice E; Farquharson, Andrew J; Mayer, Claus Dieter; Vase, Hollie F; Coates, Philip J; Steele, Robert J; Carey, Francis A

    2014-01-01

    Cancers exhibit abnormal molecular signatures associated with disease initiation and progression. Molecular signatures could improve cancer screening, detection, drug development and selection of appropriate drug therapies for individual patients. Typically only very small amounts of tissue are available from patients for analysis and biopsy samples exhibit broad heterogeneity that cannot be captured using a single marker. This report details application of an in-house custom designed GenomeLab System multiplex gene expression assay, the hCellMarkerPlex, to assess predictive gene signatures of normal, adenomatous polyp and carcinoma colon tissue using archived tissue bank material. The hCellMarkerPlex incorporates twenty-one gene markers: epithelial (EZR, KRT18, NOX1, SLC9A2), proliferation (PCNA, CCND1, MS4A12), differentiation (B4GANLT2, CDX1, CDX2), apoptotic (CASP3, NOX1, NTN1), fibroblast (FSP1, COL1A1), structural (ACTG2, CNN1, DES), gene transcription (HDAC1), stem cell (LGR5), endothelial (VWF) and mucin production (MUC2). Gene signatures distinguished normal, adenomatous polyp and carcinoma. Individual gene targets significantly contributing to molecular tissue types, classifier genes, were further characterised using real-time PCR, in-situ hybridisation and immunohistochemistry revealing aberrant epithelial expression of MS4A12, LGR5 CDX2, NOX1 and SLC9A2 prior to development of carcinoma. Identified gene signatures identify aberrant epithelial expression of genes prior to cancer development using in-house custom designed gene expression multiplex assays. This approach may be used to assist in objective classification of disease initiation, staging, progression and therapeutic responses using biopsy material.

  19. Predictive gene signatures: molecular markers distinguishing colon adenomatous polyp and carcinoma.

    Directory of Open Access Journals (Sweden)

    Janice E Drew

    Full Text Available Cancers exhibit abnormal molecular signatures associated with disease initiation and progression. Molecular signatures could improve cancer screening, detection, drug development and selection of appropriate drug therapies for individual patients. Typically only very small amounts of tissue are available from patients for analysis and biopsy samples exhibit broad heterogeneity that cannot be captured using a single marker. This report details application of an in-house custom designed GenomeLab System multiplex gene expression assay, the hCellMarkerPlex, to assess predictive gene signatures of normal, adenomatous polyp and carcinoma colon tissue using archived tissue bank material. The hCellMarkerPlex incorporates twenty-one gene markers: epithelial (EZR, KRT18, NOX1, SLC9A2, proliferation (PCNA, CCND1, MS4A12, differentiation (B4GANLT2, CDX1, CDX2, apoptotic (CASP3, NOX1, NTN1, fibroblast (FSP1, COL1A1, structural (ACTG2, CNN1, DES, gene transcription (HDAC1, stem cell (LGR5, endothelial (VWF and mucin production (MUC2. Gene signatures distinguished normal, adenomatous polyp and carcinoma. Individual gene targets significantly contributing to molecular tissue types, classifier genes, were further characterised using real-time PCR, in-situ hybridisation and immunohistochemistry revealing aberrant epithelial expression of MS4A12, LGR5 CDX2, NOX1 and SLC9A2 prior to development of carcinoma. Identified gene signatures identify aberrant epithelial expression of genes prior to cancer development using in-house custom designed gene expression multiplex assays. This approach may be used to assist in objective classification of disease initiation, staging, progression and therapeutic responses using biopsy material.

  20. Cynomolgus monkey induced pluripotent stem cells established by using exogenous genes derived from the same monkey species.

    Science.gov (United States)

    Shimozawa, Nobuhiro; Ono, Ryoichi; Shimada, Manami; Shibata, Hiroaki; Takahashi, Ichiro; Inada, Hiroyasu; Takada, Tatsuyuki; Nosaka, Tetsuya; Yasutomi, Yasuhiro

    2013-01-01

    Induced pluripotent stem (iPS) cells established by introduction of the transgenes POU5F1 (also known as Oct3/4), SOX2, KLF4 and c-MYC have competence similar to embryonic stem (ES) cells. iPS cells generated from cynomolgus monkey somatic cells by using genes taken from the same species would be a particularly important resource, since various biomedical investigations, including studies on the safety and efficacy of drugs, medical technology development, and research resource development, have been performed using cynomolgus monkeys. In addition, the use of xenogeneic genes would cause complicating matters such as immune responses when they are expressed. In this study, therefore, we established iPS cells by infecting cells from the fetal liver and newborn skin with amphotropic retroviral vectors containing cDNAs for the cynomolgus monkey genes of POU5F1, SOX2, KLF4 and c-MYC. Flat colonies consisting of cells with large nuclei, similar to those in other primate ES cell lines, appeared and were stably maintained. These cell lines had normal chromosome numbers, expressed pluripotency markers and formed teratomas. We thus generated cynomolgus monkey iPS cell lines without the introduction of ecotropic retroviral receptors or other additional transgenes by using the four allogeneic transgenes. This may enable detailed analysis of the mechanisms underlying the reprogramming. In conclusion, we showed that iPS cells could be derived from cynomolgus monkey somatic cells. To the best of our knowledge, this is the first report on iPS cell lines established from cynomolgus monkey somatic cells by using genes from the same species.

  1. Effects of common germ-line genetic variation in cell cycle genes on ovarian cancer survival

    DEFF Research Database (Denmark)

    Song, H.; Hogdall, E.; Ramus, S.J.;

    2008-01-01

    plausibly influence clinical characteristics of multiple tumors types. EXPERIMENTAL DESIGN: We examined associations between common germ-line genetic variation in 14 genes involved in cell cycle pathway (CCND1, CCND2, CCND3, CCNE1, CDKN1A, CDKN1B, CDKN2A, CDKN2B, CDKN2C, CDKN2D, CDK2, CDK4, CDK6, and RB1.......05) in these genes. The genotypes of each polymorphism were tested for association with survival by Cox regression analysis. RESULTS: A nominally statistically significant association between genotype and ovarian cancer survival was observed for polymorphisms in CCND2 and CCNE1. The per-allele hazard ratios (95......% confidence intervals) were 1.16 (1.03-1.31; P = 0.02) for rs3217933, 1.14 (1.02-1.27; P = 0.024) for rs3217901, and 0.85 (0.73-1.00; P = 0.043) for rs3217862 in CCND2 and 1.39 (1.04-1.85; P = 0.033) for rs3218038 in CCNE1. However, these were not significant after adjusting for multiple hypothesis tests...

  2. Carbon nanoparticle induced cytotoxicity in human mesenchymal stem cells through upregulation of TNF3, NFKBIA and BCL2L1 genes.

    Science.gov (United States)

    Periasamy, Vaiyapuri S; Athinarayanan, Jegan; Alfawaz, Mohammed A; Alshatwi, Ali A

    2016-02-01

    Carbon based nanomaterials, including carbon nanotubes, graphene, nanodiamond and carbon nanoparticles, have emerged as potential candidates for a wide variety of applications because of their unusual electrical, mechanical, thermal and optical properties. However, our understanding of how increased usage of carbon based nanomaterials could lead to harmful effects in humans and other biological systems is inadequate. Our present investigation is focused on the cellular toxicity of carbon nanoparticles (CNPs) on human mesenchymal stem cells (hMSCs). Following exposure to CNPs, cell viability, nuclear morphological changes, apoptosis and cell cycle progression were monitored. Furthermore, the expression of genes involved in both cell death (e.g., P53, TNF3, CDKN1A, TNFRSF1A, TNFSF10, NFKBIA, BCL2L1) and cell cycle regulation (e.g., PCNA, EGR1, E2F1, CCNG1, CCND1, CCNC, CYCD3) were assessed using qPCR. Our results indicated that CNPs reduce cell viability and cause chromatin condensation and DNA fragmentation. Cell cycle analysis indicated that CNPs affect the cell cycle progression. However, the gene expression measurements confirmed that CNPs significantly upregulated the P53, TNF3, CDKNIA, and NFKBIA genes and downregulated the EGR1 gene in hMSCs. Our findings suggest that CNPs reduce cell viability by disrupting the expression of cell death genes in human mesenchymal stem cell (hMSC). The results of this investigation revealed that CNPs exhibited moderate toxicity on hMSCs.

  3. Gene Expression Profiling in Apoptotic K562 Cells Treated by Homoharringtonine

    Institute of Scientific and Technical Information of China (English)

    Wei JIN; Jiong WU; Zhigang ZHUANG; Junjie Li; Fei FEI; Genhong DI; Ying CHEN; Ming YAO; Zhimin SHAO

    2007-01-01

    Gene chip technology was used to determine the gene expression profiles in apoptotic K562 cells induced by homoharringtonine. The expression of forty-four mRNAs was found to be changed significantly were identified after screening with a gene chip capable of detecting 14,218 different human mRNA species simultaneously. Of these genes, 17 were up-regulated and 27 were down-regulated.Most of them were found to be related to apoptosis, oncogenes, or tumor suppression. Several genes with altered gene expression, such as human transforming growth factor-beta inducible early protein gene (TIEG), vitamin D3 upregulated protein 1 gene (VDUP1), RNA binding motif protein 4 gene (RBM4) and v-myc myelocytomatosis viral oncogene homolog (C-MYC), were confirmed by Northern blot analysis.According to the dynamic gene expression pattern in these apoptotic cells, the activated transforming growth factor-β and tumor necrosis factor signaling pathways play an important role in homoharringtonine-induced apoptosis. TIEG was significantly altered after apoptosis induction, it should be critical for apoptosis signal transmission.

  4. Effects of tachyplesin and n-sodium butyrate on proliferation and gene expression of human gastric adenocarcinoma cell line BGC-823

    Institute of Scientific and Technical Information of China (English)

    Song-Lin Shi; Yong-Ye Wang; Ying Liang; Qi-Fu Li

    2006-01-01

    AIM: To investigate the effects of tachyplesin and n-sodium butyrate on proliferation and gene expression of human gastric adenocarcinoma cell line BGC-823.METHODS: Effects of tachyplesin and n-sodium butyrate on proliferation of BGC-823 cells were determined with trypan blue dye exclusion test and HE staining. Effects of tachyplesin and n-sodium butyrate on cell cycle were detected by flow cytometry. Protein levels of c-erbB-2, c-myc, p53 and p16 were examined by immunocytochemistry.RESULTS: The inhibiting effects were similar after 2.0 mg/L tachyplesin and 2.0 mmol/L n-sodium butyrate treatment, the inhibitory rate of cellular growth was 62.66% and 60.19% respectively, and the respective maximum mitotic index was decreased by 49.35% and 51.69% respectively. Tachyplesin and n-sodium butyrate treatment could markedly increase the proportion of cells at G0/G1 phase and decrease the proportion at S phase.The expression levels of oncogene c-erbB-2, c-myc, and mtp53 proteins were down-regulated while the expression level of tumor suppressor gene p16 protein was up-regulated after the treatment with tachyplesin or n-sodium butyrate. The effects of 1.0 mg/L tachyplesin in combination with 1.0 mmol/L n-sodium butyrate were obviously superior to their individual treatment in changing cell cycle distribution and expression of c-erbB-2,c-myc, mtp53 and p16 protein. The inhibitory rate of cellular growth of BGC-823 cells after combination treatment was 62.29% and the maximum mitotic index was decreased by 51.95%.CONCLUSION: Tachyplesin as a differentiation inducer of tumor cells has similar effects as n-sodium butyrate on proliferation of tumor cells, expression of correlative oncogene and tumor suppressor gene. It also has a synergistic effect on differentiation of tumor cells.

  5. [Clinical significance of cyclin Dl expression in non-small cell lung cancer].

    Science.gov (United States)

    Dworakowska, Dorota

    2005-01-01

    Lung cancer remains interdisciplinary problem. The genetic alterations in non-small cell lung cancer (NSCLC) are related to tumor suppressor genes and proto-oncogenes. CCND1 gene, coding cyclin DI, in correlation with pRb is involved in regulation of cell cycle arrest in G1 phase. Amplification of CCND1 gene and cyclin D1 over-expression was found in several cancers including head and neck cancers or colorectal cancer, where these alterations were correlated with worse prognosis. The literature addressing the clinical significance of CCND1 gene amplification/expression in NSCLC remains poor and prognostic value of these alterations in that cancer is still controversial.

  6. Dynamic telomerase gene suppression via network effects of GSK3 inhibition.

    Directory of Open Access Journals (Sweden)

    Alan E Bilsland

    Full Text Available BACKGROUND: Telomerase controls telomere homeostasis and cell immortality and is a promising anti-cancer target, but few small molecule telomerase inhibitors have been developed. Reactivated transcription of the catalytic subunit hTERT in cancer cells controls telomerase expression. Better understanding of upstream pathways is critical for effective anti-telomerase therapeutics and may reveal new targets to inhibit hTERT expression. METHODOLOGY/PRINCIPAL FINDINGS: In a focused promoter screen, several GSK3 inhibitors suppressed hTERT reporter activity. GSK3 inhibition using 6-bromoindirubin-3'-oxime suppressed hTERT expression, telomerase activity and telomere length in several cancer cell lines and growth and hTERT expression in ovarian cancer xenografts. Microarray analysis, network modelling and oligonucleotide binding assays suggested that multiple transcription factors were affected. Extensive remodelling involving Sp1, STAT3, c-Myc, NFkappaB, and p53 occurred at the endogenous hTERT promoter. RNAi screening of the hTERT promoter revealed multiple kinase genes which affect the hTERT promoter, potentially acting through these factors. Prolonged inhibitor treatments caused dynamic expression both of hTERT and of c-Jun, p53, STAT3, AR and c-Myc. CONCLUSIONS/SIGNIFICANCE: Our results indicate that GSK3 activates hTERT expression in cancer cells and contributes to telomere length homeostasis. GSK3 inhibition is a clinical strategy for several chronic diseases. These results imply that it may also be useful in cancer therapy. However, the complex network effects we show here have implications for either setting.

  7. Moringa oleifera Gold Nanoparticles Modulate Oncogenes, Tumor Suppressor Genes, and Caspase-9 Splice Variants in A549 Cells.

    Science.gov (United States)

    Tiloke, Charlette; Phulukdaree, Alisa; Anand, Krishnan; Gengan, Robert M; Chuturgoon, Anil A

    2016-10-01

    Gold nanoparticles (AuNP's) facilitate cancer cell recognition and can be manufactured by green synthesis using nutrient rich medicinal plants such as Moringa oleifera (MO). Targeting dysregulated oncogenes and tumor suppressor genes is crucial for cancer therapeutics. We investigated the antiproliferative effects of AuNP synthesized from MO aqueous leaf extracts (MLAuNP ) in A549 lung and SNO oesophageal cancer cells. A one-pot green synthesis technique was used to synthesise MLAuNP . A549, SNO cancer cells and normal peripheral blood mononuclear cells (PBMCs) were exposed to MLAuNP and CAuNP to evaluate cytotoxicity (MTT assay); apoptosis was measured by phosphatidylserine (PS) externalization, mitochondrial depolarization (ΔΨm) (flow cytometry), caspase-3/7, -9 activity, and ATP levels (luminometry). The mRNA expression of c-myc, p53, Skp2, Fbw7α, and caspase-9 splice variants was determined using qPCR, while relative protein expression of c-myc, p53, SRp30a, Bax, Bcl-2, Smac/DIABLO, Hsp70, and PARP-1 were determined by Western blotting. MLAuNP and CAuNP were not cytotoxic to PBMCs, whilst its pro-apoptotic properties were confirmed in A549 and SNO cells. MLAuNP significantly increased caspase activity in SNO cells while MLAuNP significantly increased PS externalization, ΔΨm, caspase-9, caspase-3/7 activities, and decreased ATP levels in A549 cells. Also, p53 mRNA and protein levels, SRp30a (P = 0.428), Bax, Smac/DIABLO and PARP-1 24 kDa fragment levels were significantly increased. Conversely, MLAuNP significantly decreased Bcl-2, Hsp70, Skp2, Fbw7α, c-myc mRNA, and protein levels and activated alternate splicing with caspase-9a splice variant being significantly increased. MLAuNP possesses antiproliferative properties and induced apoptosis in A549 cells by activating alternate splicing of caspase-9. J. Cell. Biochem. 117: 2302-2314, 2016. © 2016 Wiley Periodicals, Inc.

  8. SOX2 gene regulates the transcriptional network of oncogenes and affects tumorigenesis of human lung cancer cells.

    Science.gov (United States)

    Chen, Si; Xu, Yingxi; Chen, Yanan; Li, Xuefei; Mou, Wenjun; Wang, Lina; Liu, Yanhua; Reisfeld, Ralph A; Xiang, Rong; Lv, Dan; Li, Na

    2012-01-01

    Recent studies demonstrated that cancer stem cells (CSCs) have higher tumorigenesis properties than those of differentiated cancer cells and that transcriptional factor-SOX2 plays a vital role in maintaining the unique properties of CSCs; however, the function and underlying mechanism of SOX2 in carcinogenesis of lung cancer are still elusive. This study applied immunohistochemistry to analyze the expression of SOX2 in human lung tissues of normal individuals as well as patients with adenocarcinoma, squamous cell carcinoma, and large cell and small cell carcinoma and demonstrated specific overexpression of SOX2 in all types of lung cancer tissues. This finding supports the notion that SOX2 contributes to the tumorigenesis of lung cancer cells and can be used as a diagnostic probe. In addition, obviously higher expression of oncogenes c-MYC, WNT1, WNT2, and NOTCH1 was detected in side population (SP) cells than in non-side population (NSP) cells of human lung adenocarcinoma cell line-A549, revealing a possible mechanism for the tenacious tumorigenic potential of CSCs. To further elucidate the function of SOX2 in tumorigenesis of cancer cells, A549 cells were established with expression of luciferase and doxycycline-inducible shRNA targeting SOX2. We found silencing of SOX2 gene reduces the tumorigenic property of A549 cells with attenuated expression of c-MYC, WNT1, WNT2, and NOTCH1 in xenografted NOD/SCID mice. By using the RNA-Seq method, an additional 246 target cancer genes of SOX2 were revealed. These results present evidence that SOX2 may regulate the expression of oncogenes in CSCs to promote the development of human lung cancer.

  9. SOX2 gene regulates the transcriptional network of oncogenes and affects tumorigenesis of human lung cancer cells.

    Directory of Open Access Journals (Sweden)

    Si Chen

    Full Text Available Recent studies demonstrated that cancer stem cells (CSCs have higher tumorigenesis properties than those of differentiated cancer cells and that transcriptional factor-SOX2 plays a vital role in maintaining the unique properties of CSCs; however, the function and underlying mechanism of SOX2 in carcinogenesis of lung cancer are still elusive. This study applied immunohistochemistry to analyze the expression of SOX2 in human lung tissues of normal individuals as well as patients with adenocarcinoma, squamous cell carcinoma, and large cell and small cell carcinoma and demonstrated specific overexpression of SOX2 in all types of lung cancer tissues. This finding supports the notion that SOX2 contributes to the tumorigenesis of lung cancer cells and can be used as a diagnostic probe. In addition, obviously higher expression of oncogenes c-MYC, WNT1, WNT2, and NOTCH1 was detected in side population (SP cells than in non-side population (NSP cells of human lung adenocarcinoma cell line-A549, revealing a possible mechanism for the tenacious tumorigenic potential of CSCs. To further elucidate the function of SOX2 in tumorigenesis of cancer cells, A549 cells were established with expression of luciferase and doxycycline-inducible shRNA targeting SOX2. We found silencing of SOX2 gene reduces the tumorigenic property of A549 cells with attenuated expression of c-MYC, WNT1, WNT2, and NOTCH1 in xenografted NOD/SCID mice. By using the RNA-Seq method, an additional 246 target cancer genes of SOX2 were revealed. These results present evidence that SOX2 may regulate the expression of oncogenes in CSCs to promote the development of human lung cancer.

  10. Ortho-Aminoazotoluene activates mouse Constitutive Androstane Receptor (mCAR) and increases expression of mCAR target genes

    Science.gov (United States)

    Smetanina, Mariya A.; Pakharukova, Mariya Y.; Kurinna, Svitlana M.; Dong, Bingning; Hernandez, Juan P.; Moore, David D.; Merkulova, Tatyana I.

    2011-01-01

    2'-3-dimethyl-4-aminoazobenzene (ortho-aminoazotoluene, OAT) is an azo dye and a rodent carcinogen that has been evaluated by the International Agency for Research on Cancer (IARC) as a possible (class 2B) human carcinogen. Its mechanism of action remains unclear. We examined the role of the xenobiotic receptor Constitutive Androstane Receptor (CAR, NR1I3) as a mediator of the effects of OAT. We found that OAT increases mouse CAR (mCAR) transactivation in a dose-dependent manner. This effect is specific because another closely related azo dye, 3'-methyl-4-dimethyl-aminoazobenzene (3'MeDAB), did not activate mCAR. Real-time Q-PCR analysis in wild-type C57BL/6 mice revealed that OAT induces the hepatic mRNA expression of the following CAR target genes: Cyp2b10, Cyp2c29, Cyp3a11, Ugt1a1, Mrp4, Mrp2 and c-Myc. CAR-null (Car−/−) mice showed no increased expression of these genes following OAT treatment, demonstrating that CAR is required for their OAT dependent induction. The OAT-induced CAR-dependent increase of Cyp2b10 and c-Myc expression was confirmed by Western blotting. Immunohistochemistry analysis of wild-type and Car−/− livers showed that OAT did not acutely induce hepatocyte proliferation, but at much later time points showed an unexpected CAR-dependent proliferative response. These studies demonstrate that mCAR is an OAT xenosensor, and indicate that at least some of the biological effects of this compound are mediated by this nuclear receptor. PMID:21672546

  11. Effects of sulfur dioxide derivatives on expression of oncogenes and tumor suppressor genes in human bronchial epithelial cells.

    Science.gov (United States)

    Qin, Guohua; Meng, Ziqiang

    2009-04-01

    Sulfur dioxide (SO(2)) is a major air pollutant suspected to act as a promoter or co-carcinogen. The present study was designed to investigate whether SO(2) derivatives (bisulfite and sulfite) had effects on the expression of several proto-oncogenes and tumor suppressor genes in cultured human bronchial epithelial (BEP2D) cells. The mRNA and protein levels were measured by real-time RT-PCR and western blotting, respectively, following exposure to differing SO(2)-derivative concentrations and exposure times. SO(2) derivatives caused mRNA and protein over-expression of c-fos, c-jun, and c-myc at all tested doses (0.001-2mM). Over-expression of H-ras and p53 were observed in cells receiving the highest concentration (0.1-2mM), as well as the under-expression of p16 and Rb. The over-expression of c-fos and c-jun was observed after 24h recovery. The expression of c-myc and H-ras decreased to base line levels while the p53 expression decreased compared with control after 24h recovery. The mRNA and protein expression of p16 and Rb remained at initial levels after 24h recovery. The data support the hypothesis that SO(2) derivatives could cause the activation of proto-oncogenes and inactivation of tumor suppressor genes and SO(2) derivatives may play a role in the pathogenesis of SO(2)-associated lung cancer.

  12. Expression of MTLC gene in gastric carcinoma

    Institute of Scientific and Technical Information of China (English)

    Guang-Bin Qiu; Li-Guo Gong; Dong-Mei Hao; Zhi-Hong Zhen; Kai-Lai Sun

    2003-01-01

    AIM: To investigate the expression of c-myc target from laryngeal cancer cells (MTLC) gene in gastric carcinoma (GC)tissues and the effect of MTLC over-expression on gastric carcinoma cell line BGC823.METHODS: RT-PCR was performed to determine the expression of MTLC mRNA in GC and matched control tissues.BGC823 cells were transfected with an expression vector pcDNA3.1-MTLC by liposome and screened by G418. Growth of cells expressing MTLC was observed daily by manual counting. Apoptotic cells were determined by TdT-mediated dUTP nick-end labeling (TUNEL) assay.RESULTS: The expression of MTLC mRNAs was downregulated in 9(60%) of 15 cases of GC tissues. The growth rates of the BGC823 cells expressing MTLC were indistinguishable from that of control cells. A marked acceleration of apoptosis was observed in MTLC-expressing cells.CONCLUSION: MTLC was down-regulated in the majority of GC tissues and could promote apoptosis of GC cell lines,which suggests that MTLC may play an important role in the carcinogenesis of gastric carcinoma.

  13. Oncogene mRNA Imaging with Radionuclide-PNA-Peptides

    Energy Technology Data Exchange (ETDEWEB)

    Wickstrom, Eric

    2008-03-19

    New cancer gene hybridization probes to carry radionuclides were made. Noninvasive technetium-99m gamma imaging of CCND1 cancer gene activity in human breast cancer tumors in mice was demonstrated, followed by noninvasive technetium-99m imaging of MYC cancer gene activity. Noninvasive imaging of CCND1 cancer gene activity in human breast cancer tumors in mice was demonstrated with a positron-emitting copper-64 probe, followed by noninvasive positron imaging of IRS1 cancer gene activity.

  14. Identification of a new gene regulatory circuit involving B cell receptor activated signaling using a combined analysis of experimental, clinical and global gene expression data.

    Science.gov (United States)

    Schrader, Alexandra; Meyer, Katharina; Walther, Neele; Stolz, Ailine; Feist, Maren; Hand, Elisabeth; von Bonin, Frederike; Evers, Maurits; Kohler, Christian; Shirneshan, Katayoon; Vockerodt, Martina; Klapper, Wolfram; Szczepanowski, Monika; Murray, Paul G; Bastians, Holger; Trümper, Lorenz; Spang, Rainer; Kube, Dieter

    2016-07-26

    To discover new regulatory pathways in B lymphoma cells, we performed a combined analysis of experimental, clinical and global gene expression data. We identified a specific cluster of genes that was coherently expressed in primary lymphoma samples and suppressed by activation of the B cell receptor (BCR) through αIgM treatment of lymphoma cells in vitro. This gene cluster, which we called BCR.1, includes numerous cell cycle regulators. A reduced expression of BCR.1 genes after BCR activation was observed in different cell lines and also in CD10+ germinal center B cells. We found that BCR activation led to a delayed entry to and progression of mitosis and defects in metaphase. Cytogenetic changes were detected upon long-term αIgM treatment. Furthermore, an inverse correlation of BCR.1 genes with c-Myc co-regulated genes in distinct groups of lymphoma patients was observed. Finally, we showed that the BCR.1 index discriminates activated B cell-like and germinal centre B cell-like diffuse large B cell lymphoma supporting the functional relevance of this new regulatory circuit and the power of guided clustering for biomarker discovery.

  15. Methylselenol, a selenium metabolite, induces cell cycle arrest in G1 phase and apoptosis via the extracellular-regulated kinase 1/2 pathway and other cancer signaling genes.

    Science.gov (United States)

    Zeng, Huawei; Wu, Min; Botnen, James H

    2009-09-01

    Methylselenol has been hypothesized to be a critical selenium (Se) metabolite for anticancer activity in vivo, and our previous study demonstrated that submicromolar methylselenol generated by incubating methionase with seleno-l-methionine inhibits the migration and invasive potential of HT1080 tumor cells. However, little is known about the association between cancer signal pathways and methylselenol's inhibition of tumor cell invasion. In this study, we demonstrated that methylselenol exposure inhibited cell growth and we used a cancer signal pathway-specific array containing 15 different signal transduction pathways involved in oncogenesis to study the effect of methylselenol on cellular signaling. Using real-time RT-PCR, we confirmed that cellular mRNA levels of cyclin-dependent kinase inhibitor 1C (CDKN1C), heme oxygenase 1, platelet/endothelial cell adhesion molecule, and PPARgamma genes were upregulated to 2.8- to 5.7-fold of the control. BCL2-related protein A1, hedgehog interacting protein, and p53 target zinc finger protein genes were downregulated to 26-52% of the control, because of methylselenol exposure. These genes are directly related to the regulation of cell cycle and apoptosis. Methylselenol increased apoptotic cells up to 3.4-fold of the control and inhibited the extracellular-regulated kinase 1/2 (ERK1/2) signaling and cellular myelocytomatosis oncogene (c-Myc) expression. Taken together, our studies identify 7 novel methylselenol responsive genes and demonstrate that methylselenol inhibits ERK1/2 pathway activation and c-Myc expression. The regulation of these genes is likely to play a key role in G1 cell cycle arrest and apoptosis, which may contribute to the inhibition of tumor cell invasion.

  16. Effects of SOST Gene Silencing on Proliferation, Apoptosis, Invasion, and Migration of Human Osteosarcoma Cells Through the Wnt/β-Catenin Signaling Pathway.

    Science.gov (United States)

    Zou, Jian; Zhang, Wei; Li, Xiao-Lin

    2017-02-28

    Our study explored the effects of SOST gene silencing on the proliferation, apoptosis, invasion, and migration of human osteosarcoma cells through Wnt/β-catenin signaling pathway. Fresh tissues were obtained from 108 patients with osteosarcoma and 46 patients with osteochondroma. Human osteosarcoma cells (MG-63, U2-OS, HOS, and Saos-2) and normal osteoblast (hFoB1.19) were selected and cultured. Osteosarcoma cells were grouped randomly into the blank group, the scrambled control group, and the SOST-siRNA group. Cell proliferation was determined by MTT assay. Cell cycle and apoptosis were tested by flow cytometry. Transwell and scratch test were performed to determine cell invasion and migration. The qRT-PCR and Western blotting were used to detect mRNA and protein expression level of sclerostin, Wnt1, β-catenin, C-Myc, Cyclin D1, and MMP-7. The activity of caspase-3 was assessed by immunocytochemistry. Alkaline phosphatase (ALP) activity was measured using P-nitrophenylphosphate as a substrate. Low SOST mRNA and sclerostin protein expression levels were observed in osteosarcoma tissues and cells. Compared with the blank and scrambled control groups, sclerostin expression, apoptotic cells, ALP activity, and caspase-3 activity were down-regulated, while the proliferation, invasion, and migration abilities of osteosarcoma cells were evidently enhanced in the SOST-siRNA group. After SOST gene silencing, the mRNA and protein expression levels of Wnt1, β-catenin, C-Myc, Cyclin D1, and MMP-7 in osteosarcoma cells and β-catenin protein expression levels in the nucleus and cytoplasm were significantly elevated. SOST gene silencing promotes the proliferation, invasion, and migration, and inhibits apoptosis of osteosarcoma cells by activating Wnt/β-catenin signaling pathway.

  17. Metabolome, transcriptome, and bioinformatic cis-element analyses point to HNF-4 as a central regulator of gene expression during enterocyte differentiation

    DEFF Research Database (Denmark)

    Stegmann, Anders; Hansen, Morten; Wang, Yulan

    2006-01-01

    networks during the differentiation of the small intestinal epithelial cell. In addition we have searched for connections between transcription factors and the villus metabolome. Transcriptome data were generated from mouse small intestinal villus, crypt, and fetal intestinal epithelial cells. Metabolome...... data were generated from crypt and villus cells. Our results show that genes that are upregulated during fetal to adult and crypt to villus differentiation have an overrepresentation of potential hepatocyte nuclear factor (HNF)-4 binding sites in their promoters. Moreover, metabolome analyses by magic...... that are involved in lipid metabolism. Our approach also identifies transcription factors of importance for crypt functions such as DNA replication (E2F) and stem cell maintenance (c-Myc)....

  18. Generation of iPSCs from mouse fibroblasts with a single gene,Oct4,and small molecules

    Institute of Scientific and Technical Information of China (English)

    Yanqin Li; Xu Zhang; Yetao Wu; Honggang Li; Kang Liu; Chen Wu; Zhihua Song; Yang Zhao; Yan Shi; Hongkui Deng; Qiang Zhang; Xiaolei Yin; Weifeng Yang; Yuanyuan Du; Pingping Hou; Jian Ge; Chun Liu; Weiqi Zhang

    2011-01-01

    The introduction of four transcription factors Oct4,Klf4,Sox2 and c-Myc by viral transduction can induce reprogramming of somatic cells into induced pluripotent stem cells(iPSCs),but the use of iPSCs is hindered by the use of viral delivery systems.Chemical-induced reprogramming offers a novel approach to generating iPSCs without any viral vector-based genetic modification.Previous reports showed that several small molecules could replace some of the reprogramming factors although at least two transcription factors,Oct4 and Klf4,are still required to generate iPSCs from mouse embryonic fibroblasts.Here,we identify a specific chemical combination,which is sufficient to permit reprogramming from mouse embryonic and adult fibroblasts in the presence of a single transcription factor,Oct4,within 20 days,replacing Sox2,Klf4 and c-Myc.The iPSCs generated using this treatment resembled mouse embryonic stem cells in terms of global gene expression profile,epigenetic status and pluripotency both in vitro and in vivo.We also found that 8 days of Oct4 induction was sufficient to enable Oct4-induced reprogramming in the presence of the small molecules,which suggests that reprogramming was initiated within the first 8 days and was independent of continuous exogenous Oct4 expression.These discoveries will aid in the future generation of iPSCs without genetic modification,as well as elucidating the molecular mechanisms that underlie the reprogramming process.

  19. Expression of androgen receptor target genes in skeletal muscle

    Directory of Open Access Journals (Sweden)

    Kesha Rana

    2014-10-01

    Full Text Available We aimed to determine the mechanisms of the anabolic actions of androgens in skeletal muscle by investigating potential androgen receptor (AR-regulated genes in in vitro and in vivo models. The expression of the myogenic regulatory factor myogenin was significantly decreased in skeletal muscle from testosterone-treated orchidectomized male mice compared to control orchidectomized males, and was increased in muscle from male AR knockout mice that lacked DNA binding activity (ARΔZF2 versus wildtype mice, demonstrating that myogenin is repressed by the androgen/AR pathway. The ubiquitin ligase Fbxo32 was repressed by 12 h dihydrotestosterone treatment in human skeletal muscle cell myoblasts, and c-Myc expression was decreased in testosterone-treated orchidectomized male muscle compared to control orchidectomized male muscle, and increased in AR∆ZF2 muscle. The expression of a group of genes that regulate the transition from myoblast proliferation to differentiation, Tceal7 , p57 Kip2, Igf2 and calcineurin Aa, was increased in AR∆ZF2 muscle, and the expression of all but p57 Kip2 was also decreased in testosterone-treated orchidectomized male muscle compared to control orchidectomized male muscle. We conclude that in males, androgens act via the AR in part to promote peak muscle mass by maintaining myoblasts in the proliferative state and delaying the transition to differentiation during muscle growth and development, and by suppressing ubiquitin ligase-mediated atrophy pathways to preserve muscle mass in adult muscle.

  20. Expression of androgen receptor target genes in skeletal muscle.

    Science.gov (United States)

    Rana, Kesha; Lee, Nicole K L; Zajac, Jeffrey D; MacLean, Helen E

    2014-01-01

    We aimed to determine the mechanisms of the anabolic actions of androgens in skeletal muscle by investigating potential androgen receptor (AR)-regulated genes in in vitro and in vivo models. The expression of the myogenic regulatory factor myogenin was significantly decreased in skeletal muscle from testosterone-treated orchidectomized male mice compared to control orchidectomized males, and was increased in muscle from male AR knockout mice that lacked DNA binding activity (AR(ΔZF2)) versus wildtype mice, demonstrating that myogenin is repressed by the androgen/AR pathway. The ubiquitin ligase Fbxo32 was repressed by 12 h dihydrotestosterone treatment in human skeletal muscle cell myoblasts, and c-Myc expression was decreased in testosterone-treated orchidectomized male muscle compared to control orchidectomized male muscle, and increased in AR(∆ZF2) muscle. The expression of a group of genes that regulate the transition from myoblast proliferation to differentiation, Tceal7 , p57(Kip2), Igf2 and calcineurin Aa, was increased in AR(∆ZF2) muscle, and the expression of all but p57(Kip2) was also decreased in testosterone-treated orchidectomized male muscle compared to control orchidectomized male muscle. We conclude that in males, androgens act via the AR in part to promote peak muscle mass by maintaining myoblasts in the proliferative state and delaying the transition to differentiation during muscle growth and development, and by suppressing ubiquitin ligase-mediated atrophy pathways to preserve muscle mass in adult muscle.

  1. Characterization of Phototransduction Gene Knockouts Revealed Important Signaling Networks in the Light-Induced Retinal Degeneration

    Directory of Open Access Journals (Sweden)

    Jayalakshmi Krishnan

    2008-01-01

    Full Text Available Understanding the molecular pathways mediating neuronal function in retinas can be greatly facilitated by the identification of genes regulated in the retinas of different mutants under various light conditions. We attempted to conduct a gene chip analysis study on the genes regulated during rhodopsin kinase (Rhok-/- and arrestin (Sag-/- knockout and double knockouts in mice retina. Hence, mice were exposed to constant illumination of 450 lux or 6,000 lux on dilated pupils for indicated periods. The retinas were removed after the exposure and processed for microarray analysis. Double knockout was associated with immense changes in gene expression regulating a number of apoptosis inducing transcription factors. Subsequently, network analysis revealed that during early exposure the transcription factors, p53, c-MYC, c-FOS, JUN, and, in late phase, NF-B, appeared to be essential for the initiation of light-induced retinal rod loss, and some other classical pro- and antipoptotic genes appeared to be significantly important as well.

  2. Integrative transcriptomics-based identification of cryptic drivers of taxol-resistance genes in ovarian carcinoma cells: Analysis of the androgen receptor.

    Science.gov (United States)

    Sun, Nian-Kang; Huang, Shang-Lang; Lu, Hsing-Pang; Chang, Ting-Chang; Chao, Chuck C-K

    2015-09-29

    A systematic analysis of the genes involved in taxol resistance (txr) has never been performed. In the present study, we created txr ovarian carcinoma cell lines to identify the genes involved in chemoresistance. Transcriptome analysis revealed 1,194 overexpressed genes in txr cells. Among the upregulated genes, more than 12 cryptic transcription factors were identified using MetaCore analysis (including AR, C/EBPβ, ERα, HNF4α, c-Jun/AP-1, c-Myc, and SP-1). Notably, individual silencing of these transcription factors (except HNF4`)sensitized txr cells to taxol. The androgen receptor (AR) and its target genes were selected for further analysis. Silencing AR using RNA interference produced a 3-fold sensitization to taxol in txr cells, a response similar to that produced by silencing abcb1. AR silencing also downregulated the expression of prominent txr gene candidates (including abcb1, abcb6, abcg2, bmp5, fat3, fgfr2, h1f0, srcrb4d, and tmprss15). In contrast, AR activation using the agonist DHT upregulated expression of the target genes. Individually silencing seven out of nine (78%) AR-regulated txr genes sensitized txr cells to taxol. Inhibition of AKT and JNK cellular kinases using chemical inhibitors caused a dramatic suppression of AR expression. These results indicate that the AR represents a critical driver of gene expression involved in txr.

  3. Integrated genotypic analysis of hedgehog-related genes identifies subgroups of keratocystic odontogenic tumor with distinct clinicopathological features.

    Directory of Open Access Journals (Sweden)

    Yasuyuki Shimada

    Full Text Available Keratocystic odontogenic tumor (KCOT arises as part of Gorlin syndrome (GS or as a sporadic lesion. Gene mutations and loss of heterozygosity (LOH of the hedgehog receptor PTCH1 plays an essential role in the pathogenesis of KCOT. However, some KCOT cases lack evidence for gene alteration of PTCH1, suggesting that other genes in the hedgehog pathway may be affected. PTCH2 and SUFU participate in the occurrence of GS-associated tumors, but their roles in KCOT development are unknown. To elucidate the roles of these genes, we enrolled 36 KCOT patients in a study to sequence their entire coding regions of PTCH1, PTCH2 and SUFU. LOH and immunohistochemical expression of these genes, as well as the downstream targets of hedgehog signaling, were examined using surgically-excised KCOT tissues. PTCH1 mutations, including four novel ones, were found in 9 hereditary KCOT patients, but not in sporadic KCOT patients. A pathogenic mutation of PTCH2 or SUFU was not found in any patients. LOH at PTCH1 and SUFU loci correlated with the presence of epithelial budding. KCOT harboring a germline mutation (Type 1 showed nuclear localization of GLI2 and frequent histological findings such as budding and epithelial islands, as well as the highest recurrence rate. KCOT with LOH but without a germline mutation (Type 2 less frequently showed these histological features, and the recurrence rate was lower. KCOT with neither germline mutation nor LOH (Type 3 consisted of two subgroups, Type 3A and 3B, which were characterized by nuclear and cytoplasmic GLI2 localization, respectively. Type 3B rarely exhibited budding and recurrence, behaving as the most amicable entity. The expression patterns of CCND1 and BCL2 tended to correlate with these subgroups. Our data indicates a significant role of PTCH1 and SUFU in the pathogenesis of KCOT, and the genotype-oriented subgroups constitute entities with different potential aggressiveness.

  4. Integrated genotypic analysis of hedgehog-related genes identifies subgroups of keratocystic odontogenic tumor with distinct clinicopathological features.

    Science.gov (United States)

    Shimada, Yasuyuki; Katsube, Ken-ichi; Kabasawa, Yuji; Morita, Kei-ichi; Omura, Ken; Yamaguchi, Akira; Sakamoto, Kei

    2013-01-01

    Keratocystic odontogenic tumor (KCOT) arises as part of Gorlin syndrome (GS) or as a sporadic lesion. Gene mutations and loss of heterozygosity (LOH) of the hedgehog receptor PTCH1 plays an essential role in the pathogenesis of KCOT. However, some KCOT cases lack evidence for gene alteration of PTCH1, suggesting that other genes in the hedgehog pathway may be affected. PTCH2 and SUFU participate in the occurrence of GS-associated tumors, but their roles in KCOT development are unknown. To elucidate the roles of these genes, we enrolled 36 KCOT patients in a study to sequence their entire coding regions of PTCH1, PTCH2 and SUFU. LOH and immunohistochemical expression of these genes, as well as the downstream targets of hedgehog signaling, were examined using surgically-excised KCOT tissues. PTCH1 mutations, including four novel ones, were found in 9 hereditary KCOT patients, but not in sporadic KCOT patients. A pathogenic mutation of PTCH2 or SUFU was not found in any patients. LOH at PTCH1 and SUFU loci correlated with the presence of epithelial budding. KCOT harboring a germline mutation (Type 1) showed nuclear localization of GLI2 and frequent histological findings such as budding and epithelial islands, as well as the highest recurrence rate. KCOT with LOH but without a germline mutation (Type 2) less frequently showed these histological features, and the recurrence rate was lower. KCOT with neither germline mutation nor LOH (Type 3) consisted of two subgroups, Type 3A and 3B, which were characterized by nuclear and cytoplasmic GLI2 localization, respectively. Type 3B rarely exhibited budding and recurrence, behaving as the most amicable entity. The expression patterns of CCND1 and BCL2 tended to correlate with these subgroups. Our data indicates a significant role of PTCH1 and SUFU in the pathogenesis of KCOT, and the genotype-oriented subgroups constitute entities with different potential aggressiveness.

  5. Musashi1 modulates cell proliferation genes in the medulloblastoma cell line Daoy

    Directory of Open Access Journals (Sweden)

    Hung Jaclyn Y

    2008-09-01

    Full Text Available Abstract Background Musashi1 (Msi1 is an RNA binding protein with a central role during nervous system development and stem cell maintenance. High levels of Msi1 have been reported in several malignancies including brain tumors thereby associating Msi1 and cancer. Methods We used the human medulloblastoma cell line Daoy as model system in this study to knock down the expression of Msi1 and determine the effects upon soft agar growth and neurophere formation. Quantitative RT-PCR was conducted to evaluate the expression of cell proliferation, differentiation and survival genes in Msi1 depleted Daoy cells. Results We observed that MSI1 expression was elevated in Daoy cells cultured as neurospheres compared to those grown as monolayer. These data indicated that Msi1 might be involved in regulating proliferation in cancer cells. Here we show that shRNA mediated Msi1 depletion in Daoy cells notably impaired their ability to form colonies in soft agar and to grow as neurospheres in culture. Moreover, differential expression of a group of Notch, Hedgehog and Wnt pathway related genes including MYCN, FOS, NOTCH2, SMO, CDKN1A, CCND2, CCND1, and DKK1, was also found in the Msi1 knockdown, demonstrating that Msi1 modulated the expression of a subset of cell proliferation, differentiation and survival genes in Daoy. Conclusion Our data suggested that Msi1 may promote cancer cell proliferation and survival as its loss seems to have a detrimental effect in the maintenance of medulloblastoma cancer cells. In this regard, Msi1 might be a positive regulator of tumor progression and a potential target for therapy.

  6. Pokemon,c-myc and breast tumor%Pokemon、c-myc与乳腺肿瘤

    Institute of Scientific and Technical Information of China (English)

    付朝江; 崔明

    2009-01-01

    Pokemon(POK erythroid ontogenic factor)蛋白,即POK红系髓性致癌因子,是POK转录抑制物家族的一个成员,为ZBTB7基因所编码的产物.Pokemon蛋白作为转录因子参与一些细胞基因转录的调节,并在细胞分化过程中发挥着关键、多效性的功能.近来发现,Pokemon和c-myc在乳腺肿瘤致癌转化过程中发挥着至关重要的作用,并与乳腺肿瘤的发生密切相关.c-myc原癌基因编码核内DNA结合蛋白,调节其它基因的转录.其基因、mRNA及编码蛋白在多种肿瘤组织中均有异常.c-myc蛋白主要是通过促进cychnE/CDK2复合物的活性来调控G1期细胞进程的.

  7. Effects of c-Myc and TGF-Alpha on Polarized Membrane Traffic

    Science.gov (United States)

    1999-10-01

    accidental cell death due to excessive ion depletion or accumulation after loss of cell polarity. Interestingly, the CFTR chloride channel, while apical...J. Benos, and R. A. Frizzell. 1994. Polarization-dependent apical membrane CFTR targeting underlies cAMP- stimulated Cl- secretion in epithelial cells

  8. Treatment of Endocrine-Resistant Breast Cancer with a Small Molecule c-Myc Inhibitor

    Science.gov (United States)

    2015-06-01

    Medicine). 2. Based on part of the work supported by this award, last year I have submitted a DoD BCRP Breakthrough Award application entitled: ‘Targeting...Osborne CK, Schiff R, O’Malley BW. 2014. An epigenomic approach to therapy for tamoxifen-resistant breast cancer. Cell Res. 24(7): 809-19. PMID...Our work has established a novel therapeutic strategy to treat ER-positive breast cancer. Based on our study, it has been proposed that BET protein

  9. c-Myc-dependent formation of robertsonian translocation chromosomes in mouse cells

    OpenAIRE

    Amanda Guffei; Zelda Lichtensztejn; Amanda Gonçlves {ptdos} Santos Silva; Louis, Sherif F; Andrea Caporali; Sabine Mai

    2007-01-01

    Robertsonian (Rb) translocation chromosomes occur in human and murine cancers and involve the aberrant joining of two acrocentric chromosomes in humans and two telocentric chromosomes in mice. Mechanisms leading to their generation remain elusive, but models for their formation have been proposed. They include breakage of centromeric sequences and their subsequent fusions, centric misdivision, misparing between highly repetitive sequences of p- tel or p- arm repeats, and recombinational joini...

  10. c-Myc-Dependent Formation of Robertsonian Translocation Chromosomes in Mouse Cells12

    OpenAIRE

    Guffei, Amanda; Lichtensztejn, Zelda; Gonçalves dos Santos Silva, Amanda; Louis, Sherif F; Caporali, Andrea; Mai, Sabine

    2007-01-01

    Robertsonian (Rb) translocation chromosomes occur in human and murine cancers and involve the aberrant joining of two acrocentric chromosomes in humans and two telocentric chromosomes in mice. Mechanisms leading to their generation remain elusive, but models for their formation have been proposed. They include breakage of centromeric sequences and their subsequent fusions, centric misdivision, misparing between highly repetitive sequences of p-tel or p-arm repeats, and recombinational joining...

  11. Treatment of Multiple Myeloma with VLA4-targeted Nanoparticles Delivering Novel c-MYC Inhibitor Prodrug

    Science.gov (United States)

    2012-09-01

    well to chemotherapy and remissions occur in that majority of MM patients, but all patients eventually relapse and die from progressive disease within...6 years. If the residual post- remission cells of their activation to progressive disease could be disrupted with novel targeted therapies. It would...Bagnasco, L., Malacarne, D., Melchiori, A., Valente, P., Millo, E., Bruno, S., Basso, S., and Parodi, S. A retro-inverso peptide homologous to

  12. Wnt/Myc interactions in intestinal cancer: partners in crime.

    Science.gov (United States)

    Myant, Kevin; Sansom, Owen J

    2011-11-15

    Loss of the APC (adenomatous polyposis coli) gene in colorectal cancer leads to a rapid deregulation of TCF/LEF target genes. Of all these target genes, the transcription factor c-MYC appears the most critical. In this review we will discuss the interplay of Wnt and c-MYC signaling during intestinal homeostasis and transformation. Furthermore, we will discuss recent data showing that further deregulation of c-MYC levels during colorectal carcinogenesis may drive tumor progression. Moreover, understanding these additional control mechanisms may allow targeting of c-MYC during colorectal carcinogenesis.

  13. 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.

  14. Herpesvirus saimiri-mediated delivery of the adenomatous polyposis coli tumour suppressor gene reduces proliferation of colorectal cancer cells.

    Science.gov (United States)

    Macnab, Stuart A; Turrell, Susan J; Carr, Ian M; Markham, Alex F; Coletta, P Louise; Whitehouse, Adrian

    2011-11-01

    Colorectal cancer (CRC) is a major cause of cancer-related mortality. A contributing factor to the progression of this disease is sporadic or hereditary mutation of the adenomatous polyposis coli (APC) gene, a negative regulator of the Wnt signalling pathway. Inherited mutations in APC cause the disorder familial adenomatous polyposis (FAP), which leads to CRC development in early adulthood. However, the gene is also disrupted in some 60% of sporadic cancers. Restoration of functional APC may slow the growth of CRC by negatively regulating proliferation-associated genes such as c-myc. Therefore, we have cloned the cDNA of the APC tumour suppressor gene into a replication competent Herpesvirus saimiri (HVS)-based vector to assess APC gene delivery in SW480 and SW620 CRC cell lines. Our results demonstrate that full length APC protein was efficiently expressed from the HVS vector and that transgene expression inhibited proliferation of both the SW480 and the metastatic SW620 cancer cell lines. Moreover, a sustained effect could be observed for at least 8 weeks after initial infection in SW480 cells. In addition, monolayer wounding assays showed a marked reduction in proliferation and migration in HVS-GFP-APC infected cells. We believe that this is the first instance of infectious delivery and APC cDNA expression from a virus-based vector.

  15. EpCAM-regulated intramembrane proteolysis induces a cancer stem cell-like gene signature in hepatitis B virus-infected hepatocytes

    Science.gov (United States)

    Mani, Saravana Kumar Kailasam; Zhang, Hao; Diab, Ahmed; Pascuzzi, Pete E.; Lefrançois, Lydie; Fares, Nadim; Bancel, Brigitte; Merle, Philippe; Andrisani, Ourania

    2017-01-01

    Background & Aims Hepatocytes in which the hepatitis B virus (HBV) is replicating exhibit loss of the chromatin modifying polycomb repressive complex 2 (PRC2), resulting in re-expression of specific, cellular PRC2-repressed genes. Epithelial cell adhesion molecule (EpCAM) is a PRC2-repressed gene, normally expressed in hepatic progenitors, but re-expressed in hepatic cancer stem cells (hCSCs). Herein, we investigated the functional significance of EpCAM re-expression in HBV-mediated hepatocarcinogenesis. Methods Employing molecular approaches (transfections, fluorescence-activated cell sorting, immunoblotting, qRT-PCR), we investigated the role of EpCAM-regulated intramembrane proteolysis (RIP) in HBV replicating cells in vitro, and in liver tumors from HBV X/c-myc mice and chronically HBV infected patients. Results EpCAM undergoes RIP in HBV replicating cells, activating canonical Wnt signaling. Transfection of Wnt-responsive plasmid expressing green fluorescent protein (GFP) identified a GFP + population of HBV replicating cells. These GFP+/Wnt+ cells exhibited cisplatin- and sorafenib-resistant growth resembling hCSCs, and increased expression of pluripotency genes NANOG, OCT4, SOX2, and hCSC markers BAMBI, CD44 and CD133. These genes are referred as EpCAM RIP and Wnt-induced hCSC-like gene signature. Interestingly, this gene signature is also overexpressed in liver tumors of X/c-myc bitransgenic mice. Clinically, a group of HBV-associated hepatocellular carcinomas was identified, exhibiting elevated expression of the hCSC-like gene signature and associated with reduced overall survival post-surgical resection. Conclusions The hCSC-like gene signature offers promise as prognostic tool for classifying subtypes of HBV-induced HCCs. Since EpCAM RIP and Wnt signaling drive expression of this hCSC-like signature, inhibition of these pathways can be explored as therapeutic strategy for this subtype of HBV-associated HCCs. Lay summary In this study, we provide evidence

  16. Regulation of MYC gene expression by aberrant Wnt/β-catenin signaling in colorectal cancer

    Institute of Scientific and Technical Information of China (English)

    Sherri; Rennoll; Gregory; Yochum

    2015-01-01

    The Wnt/β-catenin signaling pathway controls intestinal homeostasis and mutations in components of this pathway are prevalent in human colorectal cancers(CRCs).These mutations lead to inappropriate expression of genes controlled by Wnt responsive DNA elements(WREs). T-cell factor/Lymphoid enhancer factor transcription factors bind WREs and recruit the β-catenin transcriptional co-activator to activate target gene expression. Deregulated expression of the c-MYC proto-oncogene(MYC) by aberrant Wnt/β-catenin signaling drives colorectal carcinogenesis. In this review,we discuss the current literature pertaining to the identification and characterization of WREs that control oncogenic MYC expression in CRCs. A common theme has emerged whereby these WREs often map distally to the MYC genomic locus and control MYC gene expression through long-range chromatin loops with the MYC proximal promoter. We propose that by determining which of these WREs is critical for CRC pathogenesis,novel strategies can be developed to treat individuals suffering from this disease.

  17. Construction of differentially expressed genes library of bighead carp (Aristichthys nobilis) exposed to microcystin-lr using ssh and expression profile of related genes.

    Science.gov (United States)

    Cui, Zhihui; Zhang, Kaiyue; Qu, Xiancheng; Liu, Qigen

    2011-12-01

    Microcystins (MCs) are hepatotoxic cyclic heptapeptides produced by cyanobacteria (blue-green algae). There are more than 70 MCs variants of which the most common and widely studied is MC-LR. We screened the hepatocellular differentially expressed genes against MC-LR in the bighead carp (Aristichthys nobilis). Suppression subtractive hybridization was used to construct the forward subtracted and reverse subtracted cDNA libraries, and one hundred and thirty two positive clones (seventy one in forward library and sixty one in reverse library) were randomly selected and sequenced. Finally, fifty five reliable sequences from the forward subtracted library were used in a homology search by BLASTn and BLASTx, as were 57 reliable sequences from the reverse subtracted library. Furthermore, eight analyzed sequences from the forward subtracted cDNA library and seven from the reverse subtracted library were found to be non-homologous sequences. The screening identified genes induced by MC-LR in both libraries that are involved in various processes, such as energy metabolism, immunity, and apoptosis. Some are cytoskeleton- and transportation-related genes, while signal transduction-related genes were also found. Significant genes, such as the apoptosis-related gene p53 and the proto-oncogene c-myc, are involved in inhibition of the MC-LR response in the reverse subtracted library. In addition, several immune-related genes, which play an important role in antioxidation and detoxification of MC-LR, were characterized and identified in both of the subtracted libraries. The study provides the basic data to further identify the genes and molecular mechanism of detoxification of microcystins.

  18. 益气解毒法不同组方对鼻咽癌CNE2Z细胞迁徙运动潜能及相关基因表达活性的影响*%Effects of different formulae composed from the therapeutic principle of Qi-boosting toxin-resolving on migrating potentiality and associated gene expressive activities of CNE2Z NPC cells

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    Objective To investigate the effect of different formulae composed from the therapeutic principle of Qi-boosting toxin-resolving on the migrating potentiality and associated gene expressive activities of nasopharyngeal carcinoma (NPC) cell line CNE2Z cells. Methods Firstly, different formulae derived from the same therapeutic principle of Qi-boosting toxin-resolving were composed only with their dosages changed but not with their composing kinds of herbs, i.e. the original formula (OF) and the modified one (MF). Herbal medicines-containing plasma (HMCP) were prepared routinely from rats by feeding method with these two formulae. Then, HMCP of these two formulae were cultured with CNE2Z cells in different concentrations respectively to detect their effects on migrating potentiality of these cells by scratching test. Immunohistochemical SABC assay was used to determine the expressive levels of nm23-H1 and c-myc in different groups of cells, and RT-PCR techniques were taken to confirm the transcribing activities of nm23-H1 mRNA and c-myc mRNA. Their interaction was evaluated by careful analysis on these data at last. Results TIt was shown from the experiment of scratching that the motility ability of targeting cells was significantly inhibited by the effect of OF and promoted by the effect of MF, inhibit potentiality of motility of CNE2, modified QBTRF promote potentiality of motility of CNE2. However, their effects on the expression of nm23-H1 and c-myc genes were rather complicated. OF showed no obvious effect on the expression of c-myc but giving rise a promoting effect on that of nm23-H1 protein (P0.05). In contraction, MF produced a promoting effect on the expressive activity of c-myc mRNA at higher dosage, significantly higher than that of controlling group(P0.05). Conclusion The original Qi-Boosting Toxin-Resolving formula gives rise an inhibitory effect on migrating potentiality of CNE2Z cells, while the modified Qi-Boosting Toxin-Resolving formula induces a

  19. Linkage study of nonsyndromic cleft lip with or without cleft palate using candidate genes and mapped polymorphic markers

    Energy Technology Data Exchange (ETDEWEB)

    Stein, J.D.; Nelson, L.D.; Conner, B.J. [Univ. of Texas, Houston (United States)] [and others

    1994-09-01

    Nonsyndromic cleft lip with or without cleft palate (CL(P)) involves fusion or growth failure of facial primordia during development. Complex segregation analysis of clefting populations suggest that an autosomal dominant gene may play a role in this common craniofacial disorder. We have ascertained 16 multigenerational families with CL(P) and tested linkage to 29 candidate genes and 139 mapped short tandem repeat markers. The candidate genes were selected based on their expression in craniofacial development or were identified through murine models. These include: TGF{alpha}, TGF{beta}1, TGF{beta}2, TGF{beta}3, EGF, EGFR, GRAS, cMyc, FGFR, Jun, JunB, PDFG{alpha}, PDGF{beta}, IGF2R, GCR Hox7, Hox8, Hox2B, twirler, 5 collagen and 3 extracellular matrix genes. Linkage was tested assuming an autosomal dominant model with sex-specific decreased penetrance. Linkage to all of the candidate loci was excluded in 11 families. RARA was tested and was not informative. However, haplotype analysis of markers flanking RARA on 17q allowed exclusion of this candidate locus. We have previously excluded linkage to 61 STR markers in 11 families. Seventy-eight mapped short tandem repeat markers have recently been tested in 16 families and 30 have been excluded. The remaining are being analyzed and an exclusion map is being developed based on the entire study results.

  20. TIP48/Reptin and H2A.Z requirement for initiating chromatin remodeling in estrogen-activated transcription.

    Directory of Open Access Journals (Sweden)

    Mathieu Dalvai

    2013-04-01

    Full Text Available Histone variants, including histone H2A.Z, are incorporated into specific genomic sites and participate in transcription regulation. The role of H2A.Z at these sites remains poorly characterized. Our study investigates changes in the chromatin environment at the Cyclin D1 gene (CCND1 during transcriptional initiation in response to estradiol in estrogen receptor positive mammary tumour cells. We show that H2A.Z is present at the transcription start-site and downstream enhancer sequences of CCND1 when the gene is poorly transcribed. Stimulation of CCND1 expression required release of H2A.Z concomitantly from both these DNA elements. The AAA+ family members TIP48/reptin and the histone variant H2A.Z are required to remodel the chromatin environment at CCND1 as a prerequisite for binding of the estrogen receptor (ERα in the presence of hormone. TIP48 promotes acetylation and exchange of H2A.Z, which triggers a dissociation of the CCND1 3' enhancer from the promoter, thereby releasing a repressive intragenic loop. This release then enables the estrogen receptor to bind to the CCND1 promoter. Our findings provide new insight into the priming of chromatin required for transcription factor access to their target sequence. Dynamic release of gene loops could be a rapid means to remodel chromatin and to stimulate transcription in response to hormones.

  1. Genetic variation in the immunosuppression pathway genes and breast cancer susceptibility: a pooled analysis of 42,510 cases and 40,577 controls from the Breast Cancer Association Consortium.

    Science.gov (United States)

    Lei, Jieping; Rudolph, Anja; Moysich, Kirsten B; Behrens, Sabine; Goode, Ellen L; Bolla, Manjeet K; Dennis, Joe; Dunning, Alison M; Easton, Douglas F; Wang, Qin; Benitez, Javier; Hopper, John L; Southey, Melissa C; Schmidt, Marjanka K; Broeks, Annegien; Fasching, Peter A; Haeberle, Lothar; Peto, Julian; Dos-Santos-Silva, Isabel; Sawyer, Elinor J; Tomlinson, Ian; Burwinkel, Barbara; Marmé, Frederik; Guénel, Pascal; Truong, Thérèse; Bojesen, Stig E; Flyger, Henrik; Nielsen, Sune F; Nordestgaard, Børge G; González-Neira, Anna; Menéndez, Primitiva; Anton-Culver, Hoda; Neuhausen, Susan L; Brenner, Hermann; Arndt, Volker; Meindl, Alfons; Schmutzler, Rita K; Brauch, Hiltrud; Hamann, Ute; Nevanlinna, Heli; Fagerholm, Rainer; Dörk, Thilo; Bogdanova, Natalia V; Mannermaa, Arto; Hartikainen, Jaana M; Van Dijck, Laurien; Smeets, Ann; Flesch-Janys, Dieter; Eilber, Ursula; Radice, Paolo; Peterlongo, Paolo; Couch, Fergus J; Hallberg, Emily; Giles, Graham G; Milne, Roger L; Haiman, Christopher A; Schumacher, Fredrick; Simard, Jacques; Goldberg, Mark S; Kristensen, Vessela; Borresen-Dale, Anne-Lise; Zheng, Wei; Beeghly-Fadiel, Alicia; Winqvist, Robert; Grip, Mervi; Andrulis, Irene L; Glendon, Gord; García-Closas, Montserrat; Figueroa, Jonine; Czene, Kamila; Brand, Judith S; Darabi, Hatef; Eriksson, Mikael; Hall, Per; Li, Jingmei; Cox, Angela; Cross, Simon S; Pharoah, Paul D P; Shah, Mitul; Kabisch, Maria; Torres, Diana; Jakubowska, Anna; Lubinski, Jan; Ademuyiwa, Foluso; Ambrosone, Christine B; Swerdlow, Anthony; Jones, Michael; Chang-Claude, Jenny

    2016-01-01

    Immunosuppression plays a pivotal role in assisting tumors to evade immune destruction and promoting tumor development. We hypothesized that genetic variation in the immunosuppression pathway genes may be implicated in breast cancer tumorigenesis. We included 42,510 female breast cancer cases and 40,577 controls of European ancestry from 37 studies in the Breast Cancer Association Consortium (2015) with available genotype data for 3595 single nucleotide polymorphisms (SNPs) in 133 candidate genes. Associations between genotyped SNPs and overall breast cancer risk, and secondarily according to estrogen receptor (ER) status, were assessed using multiple logistic regression models. Gene-level associations were assessed based on principal component analysis. Gene expression analyses were conducted using RNA sequencing level 3 data from The Cancer Genome Atlas for 989 breast tumor samples and 113 matched normal tissue samples. SNP rs1905339 (A>G) in the STAT3 region was associated with an increased breast cancer risk (per allele odds ratio 1.05, 95 % confidence interval 1.03-1.08; p value = 1.4 × 10(-6)). The association did not differ significantly by ER status. On the gene level, in addition to TGFBR2 and CCND1, IL5 and GM-CSF showed the strongest associations with overall breast cancer risk (p value = 1.0 × 10(-3) and 7.0 × 10(-3), respectively). Furthermore, STAT3 and IL5 but not GM-CSF were differentially expressed between breast tumor tissue and normal tissue (p value = 2.5 × 10(-3), 4.5 × 10(-4) and 0.63, respectively). Our data provide evidence that the immunosuppression pathway genes STAT3, IL5, and GM-CSF may be novel susceptibility loci for breast cancer in women of European ancestry.

  2. Cross-analysis of gene and miRNA genome-wide expression profiles in human fibroblasts at different stages of transformation.

    Science.gov (United States)

    Ostano, Paola; Bione, Silvia; Belgiovine, Cristina; Chiodi, Ilaria; Ghimenti, Chiara; Scovassi, A Ivana; Chiorino, Giovanna; Mondello, Chiara

    2012-01-01

    We have developed a cellular system constituted of human telomerase immortalized fibroblasts that gradually underwent neoplastic transformation during propagation in culture. We exploited this cellular system to investigate gene and miRNA transcriptional programs in cells at different stages of propagation, representing five different phases along the road to transformation, from non-transformed cells up to tumorigenic and metastatic ones. Here we show that gene and miRNA expression profiles were both able to divide cells according to their transformation phase. We identified more than 1,700 genes whose expression was highly modulated in cells at at least one propagation stage and we found that the number of modulated genes progressively increased at successive stages of transformation. These genes identified processes significantly deregulated in tumorigenic cells, such as cell differentiation, cell movement and extracellular matrix remodeling, cell cycle and apoptosis, together with upregulation of several cancer testis antigens. Alterations in cell cycle, apoptosis, and cancer testis antigen expression were particular hallmarks of metastatic cells. A parallel deregulation of a panel of 43 miRNAs strictly connected to the p53 and c-Myc pathways and with oncogenic/oncosuppressive functions was also found. Our results indicate that cen3tel cells can be a useful model for human fibroblast neoplastic transformation, which appears characterized by complex and peculiar alterations involving both genetic and epigenetic reprogramming, whose elucidation could provide useful insights into regulatory networks underlying cancerogenesis.

  3. Rhythmic profiles of cell cycle and circadian clock gene transcripts in mice: a possible association between two periodic systems.

    Science.gov (United States)

    Weigl, Yuval; Ashkenazi, Israel E; Peleg, Leah

    2013-06-15

    The circadian system shapes the rhythms of most biological functions. The regulation of the cell cycle by a circadian clock was suggested to operate via stages S, G2 and G2/M. This study investigated a possible time link at stages G1 and G1/S as well. The daily expression profiles of cell cycle markers (Ccnd1, Ccne1 and Pcna) and circadian clock genes (Per2 and Clock) were monitored in liver and esophagus (low and high proliferation index, respectively) of BALB/c mice. Locomotor activity displayed a 24 h rhythm, establishing the circadian organization of the suprachiasmatic nucleus. In the liver, the mRNA level of Per2 and Clock fitted the circadian rhythm with a 7.5 h shift. This temporal pattern suggests that the liver harbors a functional circadian clock. The rhythm of the analyzed cell cycle genes, however, was of low significance fitness and showed an opposite peak time between Pcna and Clock. These results indicate a weak regulatory role of the circadian clock. In the esophagus, the rhythms of Clock and Per2 mRNA had a similar peak time and non-circadian periods. These results suggest either that the esophagus does not harbor a functional circadian apparatus or that the phenotypes stem from differences in phase and amplitude of the rhythms of its various cell types. The similarity in the rhythm parameters of Clock, Ccne1 and Pcna transcripts questions the control of the circadian clock on the cell cycle along the G1 and G1/S stages. Yet the G1/S transition may play a role in modulating the local clock of proliferating tissues.

  4. Viral proliferation and expression of tumor-related gene in different chicken embryo fibroblasts infected with different tumorigenic phenotypes of avian leukosis virus subgroup J.

    Science.gov (United States)

    Qu, Yajin; Liu, Litao; Niu, Yujuan; Qu, Yue; Li, Ning; Sun, Wei; Lv, Chuanwei; Wang, Pengfei; Zhang, Guihua; Liu, Sidang

    2016-10-01

    Subgroup J avian leukosis virus (ALV-J) causes a neoplastic disease in infected chickens. The ALV-J strain NX0101, which was isolated from broiler breeders in 2001, mainly induced formation of myeloid cell tumors. However, strain HN10PY01, which was recently isolated from laying hens, mainly induces formation of myeloid cell tumors and hemangioma. To identify the molecular pathological mechanism underlying changes in host susceptibility and tumor classification induced by these two types of ALV-J strains, chicken embryo fibroblasts derived from chickens with different genetic backgrounds (broiler breeders and laying hens) and an immortalized chicken embryo fibroblasts (DF-1) were prepared and infected with strain NX0101 or HN10PY01, respectively. The 50% tissue culture infective dose (TCID50) and levels of ALV group-specific antigen p27 and heat shock protein 70 in the supernatant collected from the ALV-J infected cells were detected. Moreover, mRNA expression levels of tumor-related genes p53, c-myc, and Bcl-2 in ALV-J-infected cells were quantified. The results indicated that the infection of ALV-J could significantly increase mRNA expression levels of p53, c-myc, and Bcl-2 Strain HN10PY01 exhibited a greater influence on the three tumor-related genes in each of the three types of cells when compared with strain NX0101, and the TCID50 and p27 levels in the supernatant collected from HN10PY01-infected cells were higher than those collected from NX0101-infected cells. These results indicate that the infection of the two ALV-J strains influenced the gene expression levels in the infected cells, while the newly isolated strain HN10PY01 showed higher replication ability in cells and induced higher expression levels of tumor-related genes in infected cells. Furthermore, virus titers and expression levels of tumor-related genes and cellular stress responses of cells with different genetic backgrounds when infected with each of the two ALV-J strain were different

  5. E2F Transcription Factors Control the Roller Coaster Ride of Cell Cycle Gene Expression.

    Science.gov (United States)

    Thurlings, Ingrid; de Bruin, Alain

    2016-01-01

    Initially, the E2F transcription factor was discovered as a factor able to bind the adenovirus E2 promoter and activate viral genes. Afterwards it was shown that E2F also binds to promoters of nonviral genes such as C-MYC and DHFR, which were already known at that time to be important for cell growth and DNA metabolism, respectively. These findings provided the first clues that the E2F transcription factor might be an important regulator of the cell cycle. Since this initial discovery in 1987, several additional E2F family members have been identified, and more than 100 targets genes have been shown to be directly regulated by E2Fs, the majority of these are important for controlling the cell cycle. The progression of a cell through the cell cycle is accompanied with the increased expression of a specific set of genes during one phase of the cell cycle and the decrease of the same set of genes during a later phase of the cell cycle. This roller coaster ride, or oscillation, of gene expression is essential for the proper progression through the cell cycle to allow accurate DNA replication and cell division. The E2F transcription factors have been shown to be critical for the temporal expression of the oscillating cell cycle genes. This review will focus on how the oscillation of E2Fs and their targets is regulated by transcriptional, post-transcriptional and post-translational mechanism in mammals, yeast, flies, and worms. Furthermore, we will discuss the functional impact of E2Fs on the cell cycle progression and outline the consequences when E2F expression is disturbed.

  6. Identification of genes associated with cisplatin resistance in human oral squamous cell carcinoma cell line

    Directory of Open Access Journals (Sweden)

    Zhang Ping

    2006-09-01

    Full Text Available Abstract Background Cisplatin is widely used for chemotherapy of head and neck squamous cell carcinoma. However, details of the molecular mechanism responsible for cisplatin resistance are still unclear. The aim of this study was to identify the expression of genes related to cisplatin resistance in oral squamous cell carcinoma cells. Methods A cisplatin-resistant cell line, Tca/cisplatin, was established from a cisplatin-sensitive cell line, Tca8113, which was derived from moderately-differentiated tongue squamous cell carcinoma. Global gene expression in this resistant cell line and its sensitive parent cell line was analyzed using Affymetrix HG-U95Av2 microarrays. Candidate genes involved in DNA repair, the MAP pathway and cell cycle regulation were chosen to validate the microarray analysis results. Cell cycle distribution and apoptosis following cisplatin exposure were also investigated. Results Cisplatin resistance in Tca/cisplatin cells was stable for two years in cisplatin-free culture medium. The IC50 for cisplatin in Tca/cisplatin was 6.5-fold higher than that in Tca8113. Microarray analysis identified 38 genes that were up-regulated and 25 that were down-regulated in this cell line. Some were novel candidates, while others are involved in well-characterized mechanisms that could be relevant to cisplatin resistance, such as RECQL for DNA repair and MAP2K6 in the MAP pathway; all the genes were further validated by Real-time PCR. The cell cycle-regulated genes CCND1 and CCND3 were involved in cisplatin resistance; 24-hour exposure to 10 μM cisplatin induced a marked S phase block in Tca/cisplatin cells but not in Tca8113 cells. Conclusion The Tca8113 cell line and its stable drug-resistant variant Tca/cisplatin provided a useful model for identifying candidate genes responsible for the mechanism of cisplatin resistance in oral squamous cell carcinoma. Our data provide a useful basis for screening candidate targets for early diagnosis

  7. Novel sequential ChIP and simplified basic ChIP protocols for promoter co-occupancy and target gene identification in human embryonic stem cells

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    Elayaperumal Anuratha

    2009-06-01

    Full Text Available Abstract Background The investigation of molecular mechanisms underlying transcriptional regulation, particularly in embryonic stem cells, has received increasing attention and involves the systematic identification of target genes and the analysis of promoter co-occupancy. High-throughput approaches based on chromatin immunoprecipitation (ChIP have been widely used for this purpose. However, these approaches remain time-consuming, expensive, labor-intensive, involve multiple steps, and require complex statistical analysis. Advances in this field will greatly benefit from the development and use of simple, fast, sensitive and straightforward ChIP assay and analysis methodologies. Results We initially developed a simplified, basic ChIP protocol that combines simplicity, speed and sensitivity. ChIP analysis by real-time PCR was compared to analysis by densitometry with the ImageJ software. This protocol allowed the rapid identification of known target genes for SOX2, NANOG, OCT3/4, SOX17, KLF4, RUNX2, OLIG2, SMAD2/3, BMI-1, and c-MYC in a human embryonic stem cell line. We then developed a novel Sequential ChIP protocol to investigate in vivo promoter co-occupancy, which is basically characterized by the absence of antibody-antigen disruption during the assay. It combines centrifugation of agarose beads and magnetic separation. Using this Sequential ChIP protocol we found that c-MYC associates with the SOX2/NANOG/OCT3/4 complex and identified a novel RUNX2/BMI-1/SMAD2/3 complex in BG01V cells. These two TF complexes associate with two distinct sets of target genes. The RUNX2/BMI-1/SMAD2/3 complex is associated predominantly with genes not expressed in undifferentiated BG01V cells, consistent with the reported role of those TFs as transcriptional repressors. Conclusion These simplified basic ChIP and novel Sequential ChIP protocols were successfully tested with a variety of antibodies with human embryonic stem cells, generated a number of novel

  8. Yeast-based assay identifies novel Shh/Gli target genes in vertebrate development

    Directory of Open Access Journals (Sweden)

    Milla Luis A

    2012-01-01

    Full Text Available Abstract Background The increasing number of developmental events and molecular mechanisms associated with the Hedgehog (Hh pathway from Drosophila to vertebrates, suggest that gene regulation is crucial for diverse cellular responses, including target genes not yet described. Although several high-throughput, genome-wide approaches have yielded information at the genomic, transcriptional and proteomic levels, the specificity of Gli binding sites related to direct target gene activation still remain elusive. This study aims to identify novel putative targets of Gli transcription factors through a protein-DNA binding assay using yeast, and validating a subset of targets both in-vitro and in-vivo. Testing in different Hh/Gli gain- and loss-of-function scenarios we here identified known (e.g., ptc1 and novel Hh-regulated genes in zebrafish embryos. Results The combined yeast-based screening and MEME/MAST analysis were able to predict Gli transcription factor binding sites, and position mapping of these sequences upstream or in the first intron of promoters served to identify new putative target genes of Gli regulation. These candidates were validated by qPCR in combination with either the pharmacological Hh/Gli antagonist cyc or the agonist pur in Hh-responsive C3H10T1/2 cells. We also used small-hairpin RNAs against Gli proteins to evaluate targets and confirm specific Gli regulation their expression. Taking advantage of mutants that have been identified affecting different components of the Hh/Gli signaling system in the zebrafish model, we further analyzed specific novel candidates. Studying Hh function with pharmacological inhibition or activation complemented these genetic loss-of-function approaches. We provide evidence that in zebrafish embryos, Hh signaling regulates sfrp2, neo1, and c-myc expression in-vivo. Conclusion A recently described yeast-based screening allowed us to identify new Hh/Gli target genes, functionally important in

  9. Gene expression changes as markers of early lapatinib response in a panel of breast cancer cell lines

    LENUS (Irish Health Repository)

    O’Neill, Fiona

    2012-06-18

    AbstractBackgroundLapatinib, a tyrosine kinase inhibitor of HER2 and EGFR and is approved, in combination with capecitabine, for the treatment of trastuzumab-refractory metastatic breast cancer. In order to establish a possible gene expression response to lapatinib, a panel of breast cancer cell lines with varying sensitivity to lapatinib were analysed using a combination of microarray and qPCR profiling.MethodsCo-inertia analysis (CIA), a data integration technique, was used to identify transcription factors associated with the lapatinib response on a previously published dataset of 96 microarrays. RNA was extracted from BT474, SKBR3, EFM192A, HCC1954, MDAMB453 and MDAMB231 breast cancer cell lines displaying a range of lapatinib sensitivities and HER2 expression treated with 1 μM of lapatinib for 12 hours and quantified using Taqman RT-PCR. A fold change ≥ ± 2 was considered significant.ResultsA list of 421 differentially-expressed genes and 8 transcription factors (TFs) whose potential regulatory impact was inferred in silico, were identified as associated with lapatinib response. From this group, a panel of 27 genes (including the 8 TFs) were selected for qPCR validation. 5 genes were determined to be significantly differentially expressed following the 12 hr treatment of 1 μM lapatinib across all six cell lines. Furthermore, the expression of 4 of these genes (RB1CC1, FOXO3A, NR3C1 and ERBB3) was directly correlated with the degree of sensitivity of the cell line to lapatinib and their expression was observed to “switch” from up-regulated to down-regulated when the cell lines were arranged in a lapatinib-sensitive to insensitive order. These included the novel lapatinib response-associated genes RB1CC1 and NR3C1. Additionally, Cyclin D1 (CCND1), a common regulator of the other four proteins, was also demonstrated to observe a proportional response to lapatinib exposure.ConclusionsA panel of 5 genes were determined to be differentially

  10. The Popeye Domain Containing Genes and Their Function in Striated Muscle

    Directory of Open Access Journals (Sweden)

    Roland F. R. Schindler

    2016-06-01

    Full Text Available The Popeye domain containing (POPDC genes encode a novel class of cAMP effector proteins, which are abundantly expressed in heart and skeletal muscle. Here, we will review their role in striated muscle as deduced from work in cell and animal models and the recent analysis of patients carrying a missense mutation in POPDC1. Evidence suggests that POPDC proteins control membrane trafficking of interacting proteins. Furthermore, we will discuss the current catalogue of established protein-protein interactions. In recent years, the number of POPDC-interacting proteins has been rising and currently includes ion channels (TREK-1, sarcolemma-associated proteins serving functions in mechanical stability (dystrophin, compartmentalization (caveolin 3, scaffolding (ZO-1, trafficking (NDRG4, VAMP2/3 and repair (dysferlin or acting as a guanine nucleotide exchange factor for Rho-family GTPases (GEFT. Recent evidence suggests that POPDC proteins might also control the cellular level of the nuclear proto-oncoprotein c-Myc. These data suggest that this family of cAMP-binding proteins probably serves multiple roles in striated muscle.

  11. Design of multifunctional gold nanoparticles for in vitro and in vivo gene silencing.

    Science.gov (United States)

    Conde, João; Ambrosone, Alfredo; Sanz, Vanesa; Hernandez, Yulan; Marchesano, Valentina; Tian, Furong; Child, Hannah; Berry, Catherine C; Ibarra, M Ricardo; Baptista, Pedro V; Tortiglione, Claudia; de la Fuente, Jesus M

    2012-09-25

    Over the past decade, the capability of double-stranded RNAs to interfere with gene expression has driven new therapeutic approaches. Since small interfering RNA (siRNAs, 21 base pair double-stranded RNA) was shown to be able to elicit RNA interference (RNAi), efforts were directed toward the development of efficient delivery systems to preserve siRNA bioactivity throughout the delivery route, from the administration site to the target cell. Here we provide evidence of RNAi triggering, specifically silencing c-myc protooncogene, via the synthesis of a library of novel multifunctional gold nanoparticles (AuNPs). The efficiency of the AuNPs is demonstrated using a hierarchical approach including three biological systems of increasing complexity: in vitro cultured human cells, in vivo invertebrate (freshwater polyp, Hydra ), and in vivo vertebrate (mouse) models. Our synthetic methodology involved fine-tuning of multiple structural and functional moieties. Selection of the most active functionalities was assisted step-by-step through functional testing that adopted this hierarchical strategy. Merging these chemical and biological approaches led to a safe, nonpathogenic, self-tracking, and universally valid nanocarrier that could be exploited for therapeutic RNAi.

  12. Complex oncogenic translocations with gene amplification are initiated by specific DNA breaks in lymphocytes.

    Science.gov (United States)

    Wright, Sarah M; Woo, Yong H; Alley, Travis L; Shirley, Bobbi-Jo; Akeson, Ellen C; Snow, Kathy J; Maas, Sarah A; Elwell, Rachel L; Foreman, Oded; Mills, Kevin D

    2009-05-15

    Chromosomal instability is a hallmark of many tumor types. Complex chromosomal rearrangements with associated gene amplification, known as complicons, characterize many hematologic and solid cancers. Whereas chromosomal aberrations, including complicons, are useful diagnostic and prognostic cancer markers, their molecular origins are not known. Although accumulating evidence has implicated DNA double-strand break repair in suppression of oncogenic genome instability, the genomic elements required for chromosome rearrangements, especially complex lesions, have not been elucidated. Using a mouse model of B-lineage lymphoma, characterized by complicon formation involving the immunoglobulin heavy chain (Igh) locus and the c-myc oncogene, we have now investigated the requirement for specific genomic segments as donors for complex rearrangements. We now show that specific DNA double-strand breaks, occurring within a narrow segment of Igh, are necessary to initiate complicon formation. By contrast, neither specific DNA breaks nor the powerful intronic enhancer Emu are required for complicon-independent oncogenesis. This study is the first to delineate mechanisms of complex versus simple instability and the first to identify specific chromosomal elements required for complex chromosomal aberrations. These findings will illuminate genomic cancer susceptibility and risk factors.

  13. JMJD2A attenuation affects cell cycle and tumourigenic inflammatory gene regulation in lipopolysaccharide stimulated neuroectodermal stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Das, Amitabh, E-mail: amitabhdas.kn@gmail.com [Department of Bionanotechnology, Hanyang University, Seoul 133-791 (Korea, Republic of); Chai, Jin Choul, E-mail: jincchai@gmail.com [Department of Molecular and Life Science, Hanyang University, 1271 Sa 3-dong, Ansan 426-791, Gyeonggi-do (Korea, Republic of); Jung, Kyoung Hwa, E-mail: khjung2@gmail.com [Department of Molecular and Life Science, Hanyang University, 1271 Sa 3-dong, Ansan 426-791, Gyeonggi-do (Korea, Republic of); Das, Nando Dulal, E-mail: nando.hu@gmail.com [Clinical Research Centre, Inha University School of Medicine, Incheon 400-711 (Korea, Republic of); Kang, Sung Chul, E-mail: gujiju11@gmail.com [Department of Molecular and Life Science, Hanyang University, 1271 Sa 3-dong, Ansan 426-791, Gyeonggi-do (Korea, Republic of); Lee, Young Seek, E-mail: yslee@hanyang.ac.kr [Department of Molecular and Life Science, Hanyang University, 1271 Sa 3-dong, Ansan 426-791, Gyeonggi-do (Korea, Republic of); Seo, Hyemyung, E-mail: hseo@hanyang.ac.kr [Department of Molecular and Life Science, Hanyang University, 1271 Sa 3-dong, Ansan 426-791, Gyeonggi-do (Korea, Republic of); Chai, Young Gyu, E-mail: ygchai@hanyang.ac.kr [Department of Bionanotechnology, Hanyang University, Seoul 133-791 (Korea, Republic of); Department of Molecular and Life Science, Hanyang University, 1271 Sa 3-dong, Ansan 426-791, Gyeonggi-do (Korea, Republic of)

    2014-11-01

    JMJD2A is a lysine trimethyl-specific histone demethylase that is highly expressed in a variety of tumours. The role of JMJD2A in tumour progression remains unclear. The objectives of this study were to identify JMJD2A-regulated genes and understand the function of JMJD2A in p53-null neuroectodermal stem cells (p53{sup −/−} NE-4Cs). We determined the effect of LPS as a model of inflammation in p53{sup −/−} NE-4Cs and investigated whether the epigenetic modifier JMJD2A alter the expression of tumourigenic inflammatory genes. Global gene expression was measured in JMJD2A knockdown (kd) p53{sup −/−} NE-4Cs and in LPS-stimulated JMJD2A-kd p53{sup −/−} NE-4C cells. JMJD2A attenuation significantly down-regulated genes were Cdca2, Ccnd2, Ccnd1, Crebbp, IL6rα, and Stat3 related with cell cycle, proliferation, and inflammatory-disease responses. Importantly, some tumour-suppressor genes including Dapk3, Timp2 and TFPI were significantly up-regulated but were not affected by silencing of the JMJD2B. Furthermore, we confirmed the attenuation of JMJD2A also down-regulated Cdca2, Ccnd2, Crebbp, and Rest in primary NSCs isolated from the forebrains of E15 embryos of C57/BL6J mice with effective p53 inhibitor pifithrin-α (PFT-α). Transcription factor (TF) motif analysis revealed known binding patterns for CDC5, MYC, and CREB, as well as three novel motifs in JMJD2A-regulated genes. IPA established molecular networks. The molecular network signatures and functional gene-expression profiling data from this study warrants further investigation as an effective therapeutic target, and studies to elucidate the molecular mechanism of JMJD2A-kd-dependent effects in neuroectodermal stem cells should be performed. - Highlights: • Significant up-regulation of epigenetic modifier JMJD2A mRNA upon LPS treatment. • Inhibition of JMJD2A attenuated key inflammatory and tumourigenic genes. • Establishing IPA based functional genomics in JMJD2A-attenuated p53{sup

  14. Characterization and mapping to human chromosome 8q24.3 of Ly-6-related gene 9804 encoding an apparent homologue of mouse TSA-1.

    Science.gov (United States)

    Shan, X; Bourdeau, A; Rhoton, A; Wells, D E; Cohen, E H; Landgraf, B E; Palfree, R G

    1998-01-01

    The 9804 gene, which encodes a human Ly-6 protein most similar to mouse differentiation Ag TSA-1/Sca-2, has also been called RIG-E. Like mouse TSA-1, it has a broad tissue distribution with varied expression levels in normal human tissues and tumor cell lines. Like some members of the murine Ly-6 family, the 9804 gene is responsive to IFNs, particularly IFN-alpha. Overlapping genomic fragments spanning the 9804 gene (5543 bp) have been isolated and characterized. The gene organization is analogous to that of known mouse Ly-6 genes. The first exon, 2296 bp upstream from exon II, is entirely untranslated. The three coding exons (II, III, and IV) are separated by short introns of 321 and 131 bp, respectively. Primers were developed for specific amplification of 9804 gene fragments. Screening of human-hamster somatic cell hybrids and yeast artificial chromosomes (YACs) indicated that the gene is distal to c-Myc, located in the q arm of human chromosome 8. No positives were detected from the Centre d'Etude du Polymorphisme Humain mega-YAC A or B panels, nor from bacterial artificial chromosome libraries; two positive cosmids (c101F1 and c157F6) were isolated from a human chromosome 8 cosmid library (LA08NC01). Fluorescence in situ hybridization of metaphase spreads of chromosome 8, containing hybrid cell line 706-B6 clone 17 (CL-17) with cosmid c101F1, placed the 9804 gene close to the telomere at 8q24.3. This mapping is significant, since the region shares a homology with a portion of mouse chromosome 15, which extends into band E where Ly-6 genes reside. Moreover, the gene encoding E48, the homologue of mouse Ly-6 molecule ThB, has also been mapped to 8q24.

  15. Investigation of gene expressions in differentiated cell derived bone marrow stem cells during bone morphogenetic protein-4 treatments with Fourier transform infrared spectroscopy

    Science.gov (United States)

    Zafari, Jaber; Jouni, Fatemeh Javani; Ahmadvand, Ali; Abdolmaleki, Parviz; Soodi, Malihe; Zendehdel, Rezvan

    2017-02-01

    A model was set up to predict the differentiation patterns based on the data extracted from FTIR spectroscopy. For this reason, bone marrow stem cells (BMSCs) were differentiated to primordial germ cells (PGCs). Changes in cellular macromolecules in the time of 0, 24, 48, 72, and 96 h of differentiation, as different steps of the differentiation procedure were investigated by using FTIR spectroscopy. Also, the expression of pluripotency (Oct-4, Nanog and c-Myc) and specific genes (Mvh, Stella and Fragilis) were investigated by real-time PCR. However, the expression of genes in five steps of differentiation was predicted by FTIR spectroscopy. FTIR spectra showed changes in the template of band intensities at different differentiation steps. There are increasing changes in the stepwise differentiation procedure for the ratio area of CH2, which is symmetric to CH2 asymmetric stretching. An ensemble of expert methods, including regression tree (RT), boosting algorithm (BA), and generalized regression neural network (GRNN), was the best method to predict the gene expression by FTIR spectroscopy. In conclusion, the model was able to distinguish the pattern of different steps from cell differentiation by using some useful features extracted from FTIR spectra.

  16. Human gene control by vital oncogenes: revisiting a theoretical model and its implications for targeted cancer therapy.

    Science.gov (United States)

    Willis, Rudolph E

    2012-01-01

    An important assumption of our current understanding of the mechanisms of carcinogenesis has been the belief that clarification of the cancer process would inevitably reveal some of the crucial mechanisms of normal human gene regulation. Since the momentous work of Bishop and Varmus, both the molecular and the biochemical processes underlying the events in the development of cancer have become increasingly clear. The identification of cellular signaling pathways and the role of protein kinases in the events leading to gene activation have been critical to our understanding not only of normal cellular gene control mechanisms, but also have clarified some of the important molecular and biochemical events occurring within a cancer cell. We now know that oncogenes are dysfunctional proto-oncogenes and that dysfunctional tumor suppressor genes contribute to the cancer process. Furthermore, Weinstein and others have hypothesized the phenomenon of oncogene addiction as a distinct characteristic of the malignant cell. It can be assumed that cancer cells, indeed, become dependent on such vital oncogenes. The products of these vital oncogenes, such as c-myc, may well be the Achilles heel by which targeted molecular therapy may lead to truly personalized cancer therapy. The remaining problem is the need to introduce relevant molecular diagnostic tests such as genome microarray analysis and proteomic methods, especially protein kinase identification arrays, for each individual patient. Genome wide association studies on cancers with gene analysis of single nucleotide and other mutations in functional proto-oncogenes will, hopefully, identify dysfunctional proto-oncogenes and allow the development of more specific targeted drugs directed against the protein products of these vital oncogenes. In 1984 Willis proposed a molecular and biochemical model for eukaryotic gene regulation suggesting how proto-oncogenes might function within the normal cell. That model predicted the

  17. 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 sugges