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Sample records for astroglial c-myc overexpression

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

    DEFF Research Database (Denmark)

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

    2003-01-01

    Malignant astrocytomas are common human primary brain tumors that result from neoplastic transformation of astroglia or their progenitors. Here we show that deregulation of the c-Myc pathway in developing astroglia predisposes mice to malignant astrocytomas within 2-3 weeks of age. The genetically...

  2. Overexpression of C-MYC oncogene in prostate cancer predicts biochemical recurrence.

    Science.gov (United States)

    Hawksworth, D; Ravindranath, L; Chen, Y; Furusato, B; Sesterhenn, I A; McLeod, D G; Srivastava, S; Petrovics, G

    2010-12-01

    Alterations of chromosome 8, including amplification at 8q24 harboring the C-MYC oncogene, have been noted as one of the most common chromosomal abnormalities in prostate cancer (CaP) progression. However, the frequency of C-MYC alterations in CaP has remained uncertain. A recent study, using a new anti-MYC antibody, described prevalent upregulation of nuclear C-MYC protein expression as an early oncogenic alteration in CaP. Further, we have recently reported regulation of C-MYC expression by ERG and a significant correlation between C-MYC overexpression and TMPRSS2-ERG fusion in early stage CaP. These emerging data suggest that increased C-MYC expression may be a critical and early oncogenic event driving CaP progression. In this study, we assessed whether C-MYC mRNA overexpression in primary prostate tumors was predictive of more aggressive tumor or disease progression. Our approach was to quantitatively determine C-MYC mRNA expression levels in laser capture micro-dissected tumor cells and matched benign epithelial cells in a radical prostatectomy cohort with long follow-up data available. On the basis of our results, we conclude that elevated C-MYC expression in primary prostate tumor is biologically relevant and may be a predictor of future biochemical recurrence.

  3. 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...... an alternative modeling of the receptor-mediated carcinogenic process, compared to the currently used approaches of recombinant constitutive or conditional overexpression of oncogenic transmembrane receptor tyrosine kinases or oncogenic transcription factors....

  4. C-MYC overexpression predicts aggressive transformation and a poor outcome in mucosa-associated lymphoid tissue lymphomas.

    Science.gov (United States)

    Huang, Wenting; Guo, Lei; Liu, Hongyan; Zheng, Bo; Ying, Jianming; Lv, Ning

    2014-01-01

    Mucosa-associated lymphoid tissue (MALT) lymphoma is a relatively common, indolent B-cell lymphoma. MALT lymphoma with large tumor cells (LTCs) is believed to have the potential to transform to aggressive diffuse large B-cell lymphoma (DLBCL) which may have a poor prognosis. C-MYC is a transcription factor. Its translocation and overexpression predicts an inferior prognosis and poor response to therapy in cases of DLBCL. In the current study, C-MYC expression was detected in MALT lymphomas, and its relationship to the occurrence of LTCs, clinicopathological parameters and prognosis was assessed. A total of 69 cases were enrolled in the study, including 42 cases of MALT lymphoma without LTCs, 20 cases of MALT lymphoma with LTCs and 7 cases of DLBCL with a MALT lymphoma component (DLBCL+MALT). Immunohistochemistry and fluorescent in situ hybridization analyses were performed. In total, 15/42 (35.7%) cases were nuclear positive for C-MYC expression in the group without LTCs, whereas 15/20 (75.0%) and 4/7 (57.1%) cases were positive in the group with LTCs and in the group with DLBCL+MALT, respectively (P=0.004). Univariate and multivariate analysis were used to determine the correlations of C-MYC expression and clinicopathological parameters with overall survival (OS). C-MYC expression, Ann Arbor stage, LDH level and IPI were considerably associated with OS according to the univariate analysis. However, only C-MYC expression ≥ 20% showed a statistical significance in the multivariate analysis (HR=20.604, 95% CI: 1.909-222.412, P=0.013). Therefore, C-MYC overexpression may play an important role in aggressive transformation and is an independent prognostic factor in MALT lymphoma.

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

    Science.gov (United States)

    Knudsen, Kasper Jermiin; Nelander Holm, Gitte-Mai; Krabbe, Jonas S; Listov-Saabye, Nicolai; Kiehr, Benedicte; Dufva, Martin; Svendsen, Jette E; Oleksiewicz, Martin B

    2009-12-01

    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 overexpression, such as cell cycle disturbances, increased cell size, and overexpression of the S6 ribosomal protein. Cells overexpressing c-myc by 70% exhibited additional phenotypic changes typical of c-myc overexpression, such as increased histone H3 phosphorylation, and reduced adherence. Sorted cells also exhibited overexpression of the IGF-1R, and slightly elevated expression of the IR. Increased susceptibility to the mitogenic effect of insulin was seen in a small proportion of the sorted cells, and insulin was more effective in activating the p44/42 MAPK pathway, but not the PI3K pathway, in the sorted cells than in the nonsorted cell population. To our knowledge, this is the first in vitro system allowing functional coupling between mitogenic signaling by a well-defined growth factor and gradual overexpression of the normal, endogenous c-myc gene. Thus, our flow-sorting approach provides an alternative modeling of the receptor-mediated carcinogenic process, compared to the currently used approaches of recombinant constitutive or conditional overexpression of oncogenic transmembrane receptor tyrosine kinases or oncogenic transcription factors.

  6. RESEARCH ARTICLE Co-overexpression of EpCAM and c-myc ...

    Indian Academy of Sciences (India)

    Methods: To this purpose, 122 fresh tissues including 104 malignant and 18 benign samples were disrupted by mortar and pestle and RNA was then 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 method.

  7. C-MYC overexpression is required for continuous suppression of oncogene-induced senescence in melanoma cells.

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    Zhuang, D; Mannava, S; Grachtchouk, V; Tang, W-H; Patil, S; Wawrzyniak, J A; Berman, A E; Giordano, T J; Prochownik, E V; Soengas, M S; Nikiforov, M A

    2008-11-06

    Malignant melanomas often harbor activating mutations in BRAF (V600E) or, less frequently, in NRAS (Q61R). Intriguingly, the same mutations have been detected at higher incidences in benign nevi, which are largely composed of senescent melanocytes. Overexpression of BRAF(V600E) or NRAS(Q61R) in human melanocytes in vitro has been shown to induce senescence, although via different mechanisms. How oncogene-induced senescence is overcome during melanoma progression remains unclear. Here, we report that in the majority of analysed BRAF(V600E)- or NRAS(Q61R)-expressing melanoma cells, C-MYC depletion induced different yet overlapping sets of senescence phenotypes that are characteristic of normal melanocytes undergoing senescence due to overexpression of BRAF(V600E) or NRAS(Q61R), respectively. These senescence phenotypes were p16(INK4A)- or p53-independent, however, several of them were suppressed by genetic or pharmacological inhibition of BRAF(V600E) or phosphoinositide 3-kinase pathways, including rapamycin-mediated inhibition of mTOR-raptor in NRAS(Q61R)-expressing melanoma cells. Reciprocally, overexpression of C-MYC in normal melanocytes suppressed BRAF(V600E)-induced senescence more efficiently than NRAS(Q61R)-induced senescence, which agrees with the generally higher rates of activating mutations in BRAF than NRAS gene in human cutaneous melanomas. Our data suggest that one of the major functions of C-MYC overexpression in melanoma progression is to continuous suppress BRAF(V600E)- or NRAS(Q61R)-dependent senescence programs.

  8. Humanized c-Myc mouse.

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    Frank M Lehmann

    Full Text Available BACKGROUND: A given tumor is usually dependent on the oncogene that is activated in the respective tumor entity. This phenomenon called oncogene addiction provides the rationale for attempts to target oncogene products in a therapeutic manner, be it by small molecules, by small interfering RNAs (siRNA or by antigen-specific T cells. As the proto-oncogene product is required also for the function of normal cells, this raises the question whether there is a therapeutic window between the adverse effects of specific inhibitors or T cells to normal tissue that may limit their application, and their beneficial tumor-specific therapeutic action. To address this crucial question, suitable mouse strains need to be developed, that enable expression of the human proto-oncogene not only in tumor but also in normal cells. The aim of this work is to provide such a mouse strain for the human proto-oncogene product c-MYC. PRINCIPAL FINDINGS: We generated C57BL/6-derived embryonic stem cells that are transgenic for a humanized c-Myc gene and established a mouse strain (hc-Myc that expresses human c-MYC instead of the murine ortholog. These transgenic animals harbor the humanized c-Myc gene integrated into the endogenous murine c-Myc locus. Despite the lack of the endogenous murine c-Myc gene, homozygous mice show a normal phenotype indicating that human c-MYC can replace its murine ortholog. CONCLUSIONS: The newly established hc-Myc mouse strain provides a model system to study in detail the adverse effects of therapies that target the human c-MYC protein. To mimic the clinical situation, hc-Myc mice may be cross-bred to mice that develop tumors due to overexpression of human c-MYC. With these double transgenic mice it will be possible to study simultaneously the therapeutic efficiency and adverse side effects of MYC-specific therapies in the same mouse.

  9. 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.

  10. Domain-specific c-Myc ubiquitylation controls c-Myc transcriptional and apoptotic activity

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    Zhang, Qin; Spears, Erick; Boone, David N.; Li, Zhaoliang; Gregory, Mark A.; Hann, Stephen R.

    2013-01-01

    The oncogenic transcription factor c-Myc causes transformation and tumorigenesis, but it can also induce apoptotic cell death. Although tumor suppressors are necessary for c-Myc to induce apoptosis, the pathways and mechanisms are unclear. To further understand how c-Myc switches from an oncogenic protein to an apoptotic protein, we examined the mechanism of p53-independent c-Myc–induced apoptosis. We show that the tumor suppressor protein ARF mediates this switch by inhibiting ubiquitylation of the c-Myc transcriptional domain (TD). Whereas TD ubiquitylation is critical for c-Myc canonical transcriptional activity and transformation, inhibition of ubiquitylation leads to the induction of the noncanonical c-Myc target gene, Egr1, which is essential for efficient c-Myc–induced p53-independent apoptosis. ARF inhibits the interaction of c-Myc with the E3 ubiquitin ligase Skp2. Overexpression of Skp2, which occurs in many human tumors, inhibits the recruitment of ARF to the Egr1 promoter, leading to inhibition of c-Myc–induced apoptosis. Therapeutic strategies could be developed to activate this intrinsic apoptotic activity of c-Myc to inhibit tumorigenesis. PMID:23277542

  11. 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...

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

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

    2017-07-01

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

  13. A genetic screen to identify genes that rescue the slow growth phenotype of c-myc null fibroblasts

    NARCIS (Netherlands)

    Berns, K.; Hijmans, E.M.; Koh, E.; Daley, G.Q.; Bernards, R.A.

    2000-01-01

    The c-myc gene is frequently over-expressed in human cancers and is involved in regulation of proliferation, differentiation and apoptosis. c-Myc is a transcription factor that acts primarily by regulating the expression of other genes. However, it has been very difficult to identify bona fide c-Myc

  14. c-Myc Oncoprotein: A Dual Pathogenic Role in Neoplasia and Cardiovascular Diseases?

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    Napoli, Claudio; Lerman, Lilach O; de Nigris, Filomena; Sica, Vincenzo

    2002-01-01

    Abstract A growing body of evidence indicates that c-Myc can play a pivotal role both in neoplasia and cardiovascular diseases. Indeed, alterations of the basal machinery of the cell and perturbations of c-Myc-dependent signaling network are involved in the pathogenesis of certain cardiovascular disorders. Down-regulation of c-Myc induced by intervention with antioxidants or by antisense technology may protect the integrity of the arterial wall as well as neoplastic tissues. Further intervention studies are necessary to investigate the effects of tissue-specific block of c-Myc overexpression in the development of cardiovascular diseases. PMID:11988837

  15. [The expression of oncogene c-myc and its role on human laryngeal cancer].

    Science.gov (United States)

    Long, Xiaobo; Hu, Shuang; Cao, Pingping; Liu, Zheng; Zhen, Hongtao; Cui, Yonghua

    2009-12-01

    To detect the expression of oncogene c-myc and explore its role on human laryngeal cancer. The mRNA and of oncogene c-myc levels were detected in human laryngeal cancer tissues and laryngeal normal tissues by the means of real-time PCR and immunohistochemistry, respectively. Compared with normal laryngeal tissues, the mRNA and protein levels of oncogene c-myc were both upregulated in laryngeal cancer tissues of all differentiation degree (P<0.05). Moreover, the level of c-myc was inverse correlated with the differentiation degree in human laryngeal cancer tissues. The oncogene c-myc is overexpressed in human laryngeal cancer tissues, and c-myc may play an important role in carcinogenesis and progression of human laryngeal cancer tissues. It may provide a new target for gene therapy of human laryngeal cancer.

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

    Indian Academy of Sciences (India)

    most important proto-oncogenes routinely overexpressed in breast cancer. However, cooverexpression of EpCAM and c-myc genes 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 ...

  17. Metformin targets c-MYC oncogene to prevent prostate cancer.

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    Akinyeke, Tunde; Matsumura, Satoko; Wang, Xinying; Wu, Yingjie; Schalfer, Eric D; Saxena, Anjana; Yan, Wenbo; Logan, Susan K; Li, Xin

    2013-12-01

    Prostate cancer (PCa) is the second leading cause of cancer-related death in American men and many PCa patients develop skeletal metastasis. Current treatment modalities for metastatic PCa are mostly palliative with poor prognosis. Epidemiological studies indicated that patients receiving the diabetic drug metformin have lower PCa risk and better prognosis, suggesting that metformin may have antineoplastic effects. The mechanism by which metformin acts as chemopreventive agent to impede PCa initiation and progression is unknown. The amplification of c-MYC oncogene plays a key role in early prostate epithelia cell transformation and PCa growth. The purpose of this study is to investigate the effect of metformin on c-myc expression and PCa progression. Our results demonstrated that (i) in Hi-Myc mice that display murine prostate neoplasia and highly resemble the progression of human prostate tumors, metformin attenuated the development of prostate intraepithelial neoplasia (PIN, the precancerous lesion of prostate) and PCa lesions. (ii) Metformin reduced c-myc protein levels in vivo and in vitro. In Myc-CaP mouse PCa cells, metformin decreased c-myc protein levels by at least 50%. (iii) Metformin selectively inhibited the growth of PCa cells by stimulating cell cycle arrest and apoptosis without affecting the growth of normal prostatic epithelial cells (RWPE-1). (iv) Reduced PIN formation by metformin was associated with reduced levels of androgen receptor and proliferation marker Ki-67 in Hi-Myc mouse prostate glands. Our novel findings suggest that by downregulating c-myc, metformin can act as a chemopreventive agent to restrict prostatic neoplasia initiation and transformation. Metformin, an old antidiabetes drug, may inhibit prostate intraepithelial neoplasia transforming to cancer lesion via reducing c-MYC, an 'old' overexpressed oncogene. This study explores chemopreventive efficacy of metformin in prostate cancer and its link to cMYC in vitro and in vivo.

  18. Small molecules targeting c-Myc oncogene: promising anti-cancer therapeutics.

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    Chen, Bing-Jia; Wu, Yan-Ling; Tanaka, Yoshimasa; Zhang, Wen

    2014-01-01

    The nuclear transcription factor c-Myc is a member of the Myc gene family with multiple functions and located on band q24.1 of chromosome 8. The c-Myc gene is activated by chromosomal translocation, rearrangement, and amplification. Its encoded protein transduces intracellular signals to the nucleus, resulting in the regulation of cell proliferation, differentiation, and apoptosis, and has the ability to transform cells and bind chromosomal DNA. c-Myc also plays a critical role in malignant transformation. The abnormal over-expression of c-Myc is frequently observed in some tumors, including carcinomas of the breast, colon, and cervix, as well as small-cell lung cancer, osteosarcomas, glioblastomas, and myeloid leukemias, therefore making it a possible target for anticancer therapy. In this minireview, we summarize unique characteristics of c-Myc and therapeutic strategies against cancer using small molecules targeting the oncogene, and discuss the prospects in the development of agents targeting c-Myc, in particular G-quadruplexes formed in c-Myc promoter and c-Myc/Max dimerization. Such information will be of importance for the research and development of c-Myc-targeted drugs.

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

    Indian Academy of Sciences (India)

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

  20. p53 inhibits the upregulation of sirtuin 1 expression induced by c-Myc.

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    Yuan, Fang; Liu, Lu; Lei, Yonghong; Tang, Peifu

    2017-10-01

    Sirtuin 1 (Sirt1), a conserved NAD(+) dependent deacetylase, is a mediator of life span by calorie restriction. However, Sirt1 may paradoxically increase the risk of cancer. Accordingly, the expression level of Sirt1 is selectively elevated in numerous types of cancer cell; however, the mechanisms underlying the differential regulation remain largely unknown. The present study demonstrated that oncoprotein c-Myc was a direct regulator of Sirt1, which accounts for the upregulation of Sirt1 expression only in the cells without functional p53. In p53 deficient cells, the overexpression of c-Myc increased Sirt1 mRNA and protein expression levels as well as its promoter activity, whereas the inhibitor of c-Myc, 10058-F4, induced decreased Sirt1 basal mRNA and protein expression levels. Deletion/mutation mapping analyses revealed that c-Myc bound to the conserved E-box[-189 to -183 base pair (bp)] of the Sirt1 promoter. In addition, p53 and c-Myc shared at least response element and the presence of p53 may block the binding of c-Myc to the Sirt1 promoter, thus inhibit the c-Myc mediated upregulation of Sirt1 promoter activity. The present study indicated that the expression level of Sirt1 was tightly regulated by oncoprotein c-Myc and tumor suppressor p53, which aids an improved understanding of its expression regulation and tumor promoter role in certain conditions.

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

    Science.gov (United States)

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

    2004-01-01

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

  2. c-MYC—Making Liver Sick: Role of c-MYC in Hepatic Cell Function, Homeostasis and Disease

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    Zheng, Kang; Cubero, Francisco Javier; Nevzorova, Yulia A.

    2017-01-01

    Over 35 years ago, c-MYC, a highly pleiotropic transcription factor that regulates hepatic cell function, was identified. In recent years, a considerable increment in the number of publications has significantly shifted the way that the c-MYC function is perceived. Overexpression of c-MYC alters a wide range of roles including cell proliferation, growth, metabolism, DNA replication, cell cycle progression, cell adhesion and differentiation. The purpose of this review is to broaden the understanding of the general functions of c-MYC, to focus on c-MYC-driven pathogenesis in the liver, explain its mode of action under basal conditions and during disease, and discuss efforts to target c-MYC as a plausible therapy for liver disease. PMID:28422055

  3. Targeted overexpression of an activated N-ras gene results in B-cell and plasma cell lymphoproliferation and cooperates with c-myc to induce fatal B-cell neoplasia.

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    Linden, Michael A; Kirchhof, Nicole; Carlson, Cathy S; Van Ness, Brian G

    2012-03-01

    Multiple myeloma is an incurable malignant expansion of plasma cells in the bone marrow. Although there is no pathognomonic genetic lesion among multiple myeloma patients, activation of the ras gene has been identified as a common mutation. We have previously described the use of the 3' κ immunoglobulin light chain enhancer (3'KE) to target transgenic expression in murine B and plasma cells, resulting in bcl-X(L) and c-myc-driven murine models of multiple myeloma. In this report, we characterize the role of activated mutant N-ras in B and plasma cells in transgenic mice. We constructed transgenic mice that use 3'KE to direct expression of a mutant activated N-ras. We also crossed the N-ras mice with mice bearing a c-myc transgene to study the cooperative effects of the transgenic constructs. Mice were sacrificed when moribund or at specific time intervals and characterized by serology, light microscopy, and flow cytometry. The transgenic N-ras animals develop B- and plasma cell lymphoproliferation, and aged mice develop immunoglobulinemia, renal hyaline tubular casts, and microscopic foci of abnormal plasma cells in extramedullary sites, including the liver and kidney. Bitransgenic 3'KE/N-Ras V12 × Eμ-c-Myc mice develop fatal B-cell neoplasia, with a median survival of 10 weeks. These data indicate that activated N-ras can play a role in B- and plasma cell homeostasis and that activated N-Ras and c-Myc can cooperate to induce B-cell neoplasia. Copyright © 2012 ISEH - Society for Hematology and Stem Cells. Published by Elsevier Inc. All rights reserved.

  4. 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.

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

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    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.

  6. ADA3 regulates normal and tumor mammary epithelial cell proliferation through c-MYC.

    Science.gov (United States)

    Griffin, Nicolas I; Sharma, Gayatri; Zhao, Xiangshan; Mirza, Sameer; Srivastava, Shashank; Dave, Bhavana J; Aleskandarany, Mohammed; Rakha, Emad; Mohibi, Shakur; Band, Hamid; Band, Vimla

    2016-11-16

    We have established the critical role of ADA3 as a coactivator of estrogen receptor (ER), as well as its role in cell cycle progression. Furthermore, we showed that ADA3 is predominantly nuclear in mammary epithelium, and in ER+, but is cytoplasmic in ER- breast cancers, the latter correlating with poor survival. However, the role of nuclear ADA3 in human mammary epithelial cells (hMECs), and in ER+ breast cancer cells, as well as the importance of ADA3 expression in relation to patient prognosis and survival in ER+ breast cancer have remained uncharacterized. We overexpressed ADA3 in hMECs or in ER+ breast cancer cells and assessed the effect on cell proliferation. The expression of ADA3 was analyzed then correlated with the expression of various prognostic markers, as well as survival of breast cancer patients. Overexpression of ADA3 in ER- hMECs as well as in ER+ breast cancer cell lines enhanced cell proliferation. These cells showed increased cyclin B and c-MYC, decreased p27 and increased SKP2 levels. This was accompanied by increased mRNA levels of early response genes c-FOS, EGR1, and c-MYC. Analysis of breast cancer tissue specimens showed a significant correlation of ADA3 nuclear expression with c-MYC expression. Furthermore, nuclear ADA3 and c-MYC expression together showed significant correlation with tumor grade, mitosis, pleomorphism, NPI, ER/PR status, Ki67 and p27 expression. Importantly, within ER+ cases, expression of nuclear ADA3 and c-MYC also significantly correlated with Ki67 and p27 expression. Univariate Kaplan Meier analysis of four groups in the whole, as well as the ER+ patients showed that c-MYC and ADA3 combinatorial phenotypes showed significantly different breast cancer specific survival with c-MYC-high and ADA3-Low subgroup had the worst outcome. Using multivariate analyses within the whole cohort and the ER+ subgroups, the significant association of ADA3 and c-MYC expression with patients' outcome was independent of tumor grade

  7. Deubiquitinating enzyme USP22 positively regulates c-Myc stability and tumorigenic activity in mammalian and breast cancer cells.

    Science.gov (United States)

    Kim, Dongyeon; Hong, Ahyoung; Park, Hye In; Shin, Woo Hyun; Yoo, Lang; Jeon, Seo Jeong; Chung, Kwang Chul

    2017-12-01

    The proto-oncogene c-Myc has a pivotal function in growth control, differentiation, and apoptosis and is frequently affected in human cancer, including breast cancer. Ubiquitin-specific protease 22 (USP22), a member of the USP family of deubiquitinating enzymes (DUBs), mediates deubiquitination of target proteins, including histone H2B and H2A, telomeric repeat binding factor 1, and cyclin B1. USP22 is also a component of the mammalian SAGA transcriptional co-activating complex. In this study, we explored the functional role of USP22 in modulating c-Myc stability and its physiological relevance in breast cancer progression. We found that USP22 promotes deubiquitination of c-Myc in several breast cancer cell lines, resulting in increased levels of c-Myc. Consistent with this, USP22 knockdown reduces c-Myc levels. Furthermore, overexpression of USP22 stimulates breast cancer cell growth and colony formation, and increases c-Myc tumorigenic activity. In conclusion, the present study reveals that USP22 in breast cancer cell lines increases c-Myc stability through c-Myc deubiquitination, which is closely correlated with breast cancer progression. © 2017 Wiley Periodicals, Inc.

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

    Science.gov (United States)

    Sadeghi, Samira; Hojati, Zohreh; Tabatabaeian, Hossein

    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-myc genes 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 by 2 -ΔΔCt method using RT-qPCR. EpCAM protein level was also assessed in 66 cases using Western blot technique. Using RT-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. c-MYC Copy-Number Gain Is an Independent Prognostic Factor in Patients with Colorectal Cancer.

    Science.gov (United States)

    Lee, Kyu Sang; Kwak, Yoonjin; Nam, Kyung Han; Kim, Duck-Woo; Kang, Sung-Bum; Choe, Gheeyoung; Kim, Woo Ho; Lee, Hye Seung

    2015-01-01

    The aim of this study was to determine the incidence and clinicopathological significance of c-MYC gene copy-number (GCN) gain in patients with primary colorectal cancer (CRC). The c-MYC GCN was investigated in 367 consecutive CRC patients (cohort 1) by using dual-color silver in situ hybridization. Additionally, to evaluate regional heterogeneity, we examined CRC tissue from 3 sites including the primary cancer, distant metastasis, and lymph-node metastasis in 152 advanced CRC patients (cohort 2). KRAS exons 2 and 3 were investigated for mutations. In cohort 1, c-MYC gene amplification, defined by a c-MYC:centromere of chromosome 8 ratio ≥ 2.0, was detected in 31 (8.4%) of 367 patients. A c-MYC GCN gain, defined by ≥ 4.0 c-MYC copies/nucleus, was found in 63 (17.2%) patients and was associated with poor prognosis (P = 0.015). Multivariate Cox regression analysis showed that the hazard ratio for c-MYC GCN gain was 2.35 (95% confidence interval, 1.453-3.802; P patients, c-MYC GCN gain was significantly associated with poor prognosis by univariate (P = 0.034) and multivariate (P = 0.040) analyses. c-MYC protein overexpression was observed in 201 (54.8%) out of 367 patients and weakly correlated with c-MYC GCN gain (ρ, 0.211). In cohort 2, the c-MYC genetic status was heterogenous in advanced CRC patients. Discordance between GCN gain in the primary tumor and either distant or lymph-node metastasis was 25.7% and 30.4%, respectively. A similar frequency for c-MYC GCN gain and amplification was observed in CRC patients with both wild-type and mutated KRAS. c-MYC GCN gain was an independent factor for poor prognosis in consecutive CRC patients and in the stage II-III subgroup. Our findings indicate that the status of c-MYC may be helpful in predicting the patients' outcome and for managing CRC patients.

  10. Deficiency in the DNA glycosylases UNG1 and OGG1 does not potentiate c-Myc-induced B-cell lymphomagenesis

    DEFF Research Database (Denmark)

    Green, Blerta; Martin, Alberto; Belcheva, Antoaneta

    2017-01-01

    C-Myc overexpression mediates lymphomagenesis, however, secondary genetic lesions are required for its full oncogenic potential. The origin and the mechanism of formation of these mutations are unclear. Here we investigated the role of Ogg1 and UNG glycosylases in c-Myc driven lymphomagenesis...... but found that their deficiencies did not influence the disease outcome in the Eµ c-Myc model. We also found that Rag proteins do not contribute to this process. Instead, our work suggests that secondary mutations that potentiate C-Myc lymphomagenesis arise early in B-cell ontogeny, occur at C:G basepairs...

  11. Acidosis decreases c-Myc oncogene expression in human lymphoma cells: a role for the proton-sensing G protein-coupled receptor TDAG8.

    Science.gov (United States)

    Li, Zhigang; Dong, Lixue; Dean, Eric; Yang, Li V

    2013-10-11

    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.

  12. 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.

  13. C-MYC aberrations as prognostic factors in diffuse large B-cell lymphoma: a meta-analysis of epidemiological studies.

    Directory of Open Access Journals (Sweden)

    Kuangguo Zhou

    Full Text Available OBJECTIVES: Various studies have investigated the prognostic value of C-MYC aberrations in diffuse large B-cell lymphoma (DLBCL. However, the role of C-MYC as an independent prognostic factor in clinical practice remains controversial. A systematic review and meta-analysis were performed to clarify the clinical significance of C-MYC aberrations in DLBCL patients. METHODS: The pooled hazard ratios (HRs for overall survival (OS and event-free survival (EFS were calculated as the main effect size estimates. The procedure was conducted according to the Cochrane handbook and PRISMA guidelines, including the use of a heterogeneity test, publication bias assessment, and meta-regression, as well as subgroup analyses. RESULTS: Twenty-four eligible studies enrolling 4662 patients were included in this meta-analysis. According to the nature of C-MYC aberrations (gene, protein, and mRNA, studies were divided into several subgroups. For DLBCL patients with C-MYC gene abnormalities, the combined HR was 2.22 (95% confidence interval, 1.89 to 2.61 for OS and 2.29 (95% confidence interval, 1.81 to 2.90 for EFS, compared to patients without C-MYC gene abnormalities. For DLBCL patients with overexpression of C-MYC protein and C-MYC mRNA, pooled HRs for OS were 2.13 and 1.62, respectively. C-MYC aberrations appeared to play an independent role among other well-known prognostic factors in DLBCL. Addition of rituximab could not overcome the inferior prognosis conferred by C-MYC. CONCLUSION: The present systematic review and meta-analysis confirm the prognostic value of C-MYC aberrations. Screening of C-MYC should have definite prognostic meaning for DLBCL stratification, thus guaranteeing a more tailored therapy.

  14. A proteomic study of cMyc improvement of CHO culture

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    Dunn Michael J

    2010-03-01

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

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

    NARCIS (Netherlands)

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

    1998-01-01

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

  19. Impact of C-Myc gene-related aberrations in newly diagnosed myeloma with bortezomib/dexamethasone therapy.

    Science.gov (United States)

    Sekiguchi, Naohiro; Ootsubo, Kaori; Wagatsuma, Miyuki; Midorikawa, Kiyoe; Nagata, Akihisa; Noto, Satoshi; Yamada, Kazuaki; Takezako, Naoki

    2014-03-01

    Recent studies have suggested that c-Myc over-expression may be a factor indicating poor prognosis in multiple myeloma (MM), although c-Myc gene-related abnormalities, including translocation and gene amplification, have not been fully investigated in the novel agent era. Additional chromosome 8 may be considered as aggressive disease in the 1990s. To clarify the impact of these aberrations, we retrospectively analyzed newly diagnosed MM (NDMM) and relapsed/refractory MM (RRMM) with bortezomib and dexamethasone induction therapy. In the present study, the high-risk group was defined as having at least one of the following present: non-hyperdiploidy, IgH/FGFR3, and del p53. Forty NDMM cases were analyzed. At the median follow-up duration of 14.1 months, 14 RRMM were recognized. The proportions of patients in the high-risk, c-Myc gene-related aberrations, and additional chromosome 8 groups at diagnosis were 45.5, 22.5, and 10 %, respectively. The proportions of patients who developed RRMM in the high-risk, c-Myc gene-related aberrations, and additional chromosome 8 groups were 41.7, 77.7, and 50 %, respectively. Furthermore, patients with c-Myc gene-related abnormalities tended to exhibit inferior progression-free survival (PFS), and those with c-Myc gene-related abnormalities and/or additional chromosome 8 showed statistically shorter PFS. Therefore, c-Myc gene-related abnormalities and additional chromosome 8 may be related to a poorer prognosis.

  20. miR-494 acts as an anti-oncogene in gastric carcinoma by targeting c-myc.

    Science.gov (United States)

    He, Weiling; Li, Yuhuang; Chen, Xinlin; Lu, Liya; Tang, Bin; Wang, Zhixiong; Pan, Yunbao; Cai, Shirong; He, Yulong; Ke, Zunfu

    2014-01-01

    We recently showed that miR-494 was downregulated in gastric carcinoma (GC). The objectives of this study were to determine the role of miR-494 in GC malignancy and to identify its target genes. Real-time polymerase chain reaction was employed to quantify the expression level of miR-494 and c-myc in gastric cancer tissues. Bioinformatics was used to predict the downstream target genes of miR-494, which were confirmed by luciferase and RNA immunoprecipitation assays. Cell functional analyses and a xenograft mouse model were used to evaluate the role of miR-494 in malignancy. miR-494 was downregulated in human GC tissues and in GC cells and was negatively correlated with c-myc expression. High level of c-myc or low level of miR-494 correlated with poor prognosis. The miR-494-binding site in the c-myc 3' untranslated region was predicted using TargetScan and was confirmed by the luciferase assay. Additionally, c-myc and miR-494 were enriched in coimmunoprecipitates with tagged Argonaute2 proteins in cells overexpressing miR-494. Furthermore, a miR-494 mimic significantly downregulated endogenous c-myc expression, which may contribute to the delayed G1/S transition, decreased synthesis phase bromodeoxyuridine incorporation, and impaired cell growth and colony formation; on the other hand, treatment with a miR-494 inhibitor displayed the opposite effects. Reduced tumor burden and decreased cell proliferation were observed following the delivery of miR-494 into xenograft mice. miR-494 is downregulated in human GC and acts as an anti-oncogene by targeting c-myc. miR-494 plays a role in the pathogenesis of gastric cancer in a recessive fashion. © 2014 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd.

  1. Systematic analysis of the contribution of c-myc mRNA constituents upon cap and IRES mediated translation.

    Science.gov (United States)

    Meristoudis, Christos; Trangas, Theoni; Lambrianidou, Andromachi; Papadopoulos, Vasilios; Dimitriadis, Euthymios; Courtis, Nelly; Ioannidis, Panayotis

    2015-12-01

    Fine tuning of c-MYC expression is critical for its action and is achieved by several regulatory mechanisms. The contribution of c-myc mRNA regulatory sequences on its translational control has been investigated individually. However, putative interactions have not been addressed so far. The effect of these interactions upon the translatability of monocistronic and bicistronic chimaeric mRNAs, carrying combinations of the c-myc mRNA 5'-untranlated region (UTR), 3'-UTR, and coding region instability element (CRD) was investigated on this study. The presence of the 5'-UTR induced an increase in translatability of 50%. The presence of the CRD element, when in frame, reduced translatability by approximately 50%, regardless of the expression levels of the wild type CRD- binding protein (CRD-BP/IMP1). Conversely, overexpression of a mutated CRD-BP/IMP1 (Y396F) further impeded translation of the chimaeric mRNAs carrying its cognate sequences. The presence of the c-myc 3'-UTR increased translatability by approximately 300% affecting both cap and c-myc internal ribosome entry site (IRES) mediated translation. In addition, 3'-UTR rescued the cap mediated translation in the presence of the polyadenylation inhibitor cordycepin. Furthermore, the 3'-UTR rescued cap mediated translation under metabolic stress conditions and this was enhanced in the absence of a long poly (A) tail.

  2. Patients with high c-MYC-expressing squamous cell carcinomas of the tongue show better survival than those with low- and medium-expressing tumours.

    Science.gov (United States)

    Strindlund, Klas; Troiano, Giuseppe; Sgaramella, Nicola; Coates, Philip J; Gu, Xiaolian; Boldrup, Linda; Califano, Luigi; Fahraeus, Robin; Muzio, Lorenzo Lo; Ardito, Fatima; Colella, Giuseppe; Tartaro, Gianpaolo; Franco, Renato; Norberg-Spaak, Lena; Saadat, Mohammad; Nylander, Karin

    2017-11-01

    c-MYC is a potent oncoprotein with roles in a wide range of cellular processes such as differentiation, apoptosis and growth control. Deregulation of the MYC gene is commonly seen in human tumours resulting in overexpression of the protein. Here we studied expression of c-MYC in correlation to clinical outcome in patients with primary squamous cell carcinoma of the mobile tongue. Immunohistochemistry was used to identify c-MYC in a group of 104 tongue squamous cell carcinomas with an antibody directed against the N-terminal part of the protein. Staining was evaluated by multiplying the percentage of c-MYC-expressing cells with staining intensity, giving a quick score for each tumour. All 104 tumours expressed c-MYC at varying levels. Quantitation according to per cent of positive cells and staining intensity revealed that most (15/21; 71%) high-expressing tumours were seen in males. Within the group of high c-MYC-expressing tumours, the majority were alive 2 and 5 years after treatment. The present findings show that expression of c-MYC has prognostic value in squamous cell carcinoma of the tongue, and could be useful in choice of therapy. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  3. Expression of c-myc oncogene in coeliac disease.

    OpenAIRE

    P. J. Ciclitira; Stewart, J.(DESY, 15738, Zeuthen, Germany); Evan, G; Wight, D G; Sikora, K

    1987-01-01

    A monoclonal antibody, produced by peptide immunisation was used to detect the distribution of p62c/myc by immunohistology in normal and coeliac small intestinal mucosa. The effect of gluten in four treated coeliac patients was investigated by taking serial jejunal biopsy specimens for six hours after a 10 g oral gluten challenge. There was a progressive increase in p62c/myc staining intensity in the villus enterocytes extending to the crypts, which accompanied the classical morphological cha...

  4. c-Myc-Induced Extrachromosomal Elements Carry Active Chromatin

    Directory of Open Access Journals (Sweden)

    Greg Smith

    2003-03-01

    Full Text Available Murine Pre-13 lymphocytes with experimentally activated MycER show both chromosomal and extrachromosomal gene amplification. In this report, we have elucidated the size, structure, functional components of c-Myc-induced extrachromosomal elements (EEs. Scanning electron microscopy revealed that EEs isolated from MycER-activated Pre-B+ cells are an average of 10 times larger than EEs isolated from non-MycER-activated control Pre-B- cells. We demonstrate that these large c-Myc-induced EEs are associated with histone proteins, whereas EEs of non-MycER-activated Pre B- cells are not. Immunohistochemistry and Western blot analyses using pan -histone-specific, histone H3 phosphorylation-specific, histone H4 acetylation-specific antibodies indicate that a significant proportion of EEs analyzed from MycER-activated cells harbors transcriptionally competent and/or active chromatin. Moreover, these large, c-Myc-induced EEs carry genes. Whereas the total genetic make-up of these c-Myc-induced EEs is unknown, we found that 30.2% of them contain the dihydrofolate reductase (DHFR gene, whereas cyclin C (CCNC was absent. In addition, 50% of these c-Myc-activated Pre-B+ EEs incorporated bromodeoxyuridine (BrdU, identifying them as genetic structures that self-propagate. In contrast, EEs isolated from non-Myc-activated cells neither carry the DHFR gene nor incorporate BrdU, suggesting that c-Myc deregulation generates a new class of EEs.

  5. 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

  6. Acidified bile acids enhance tumor progression and telomerase activity of gastric cancer in mice dependent on c-Myc expression.

    Science.gov (United States)

    Wang, Xiaolong; Sun, Lei; Wang, Xijing; Kang, Huafeng; Ma, Xiaobin; Wang, Meng; Lin, Shuai; Liu, Meng; Dai, Cong; Dai, Zhijun

    2017-04-01

    c-Myc overexpression has been implicated in several malignancies including gastric cancer. Here, we report that acidified bile acids enhance tumor progression and telomerase activity in gastric cancer via c-Myc activation both in vivo and in vitro. c-Myc mRNA and protein levels were assessed in ten primary and five local recurrent gastric cancer samples by quantitative real-time polymerase chain reaction and western blotting analysis. The gastric cancer cell line MGC803 was exposed to bile salts (100 μmol/L glycochenodeoxycholic acid and deoxycholic acid) in an acid medium (pH 5.5) for 10 min daily for 60 weeks to develop an MGC803-resistant cell line. Control MGC803 cells were grown without acids or bile salts for 60 weeks as a control. Cell morphology, proliferation, colony formation and apoptosis of MGC803-resistant cells were analyzed after 60 weeks. To determine the involvement of c-Myc in tumor progression and telomere aging in MGC803-resistant cells, we generated xenografts in nude mice and measured xenograft volume and in vivo telomerase activity. The c-Myc and hTERT protein and mRNA levels were significantly higher in local recurrent gastric cancer samples than in primary gastric cancer samples. MGC803-resistant cells showed a marked phenotypic change under normal growth conditions with more clusters and acini, and exhibited increased cell viability and colony formation and decreased apoptosis in vitro. These phenotypic changes were found to be dependent on c-Myc activation using the c-Myc inhibitor 10058-F4. MGC803-resistant cells also showed a c-Myc-dependent increase in xenograft growth and telomerase activity in vivo. In conclusion, these observations support the hypothesis that acidified bile acids enhance tumor progression and telomerase activity in gastric cancer and that these effects are dependent on c-Myc activity. These findings suggest that acidified bile acids play an important role in the malignant progression of local recurrent

  7. CUDR promotes liver cancer stem cell growth through upregulating TERT and C-Myc

    Science.gov (United States)

    Pu, Hu; Zheng, Qidi; Li, Haiyan; Wu, Mengying; An, Jiahui; Gui, Xin; Li, Tianming; Lu, Dongdong

    2015-01-01

    Cancer up-regulated drug resistant (CUDR) is a novel non-coding RNA gene. Herein, we demonstrate excessive CUDR cooperates with excessive CyclinD1 or PTEN depletion to accelerate liver cancer stem cells growth and liver stem cell malignant transformation in vitro and in vivo. Mechanistically, we reveal the decrease of PTEN in cells may lead to increase binding capacity of CUDR to CyclinD1. Therefore, CUDR-CyclinD1 complex loads onto the long noncoding RNA H19 promoter region that may lead to reduce the DNA methylation on H19 promoter region and then to enhance the H19 expression. Strikingly, the overexpression of H19 increases the binding of TERT to TERC and reduces the interplay between TERT with TERRA, thus enhancing the cell telomerase activity and extending the telomere length. On the other hand, insulator CTCF recruits the CUDR-CyclinD1 complx to form the composite CUDR-CyclinD1-insulator CTCF complex which occupancied on the C-myc gene promoter region, increasing the outcome of oncogene C-myc. Ultimately, excessive TERT and C-myc lead to liver cancer stem cell and hepatocyte-like stem cell malignant proliferation. To understand the novel functions of long noncoding RNA CUDR will help in the development of new liver cancer therapeutic and diagnostic approaches. PMID:26513297

  8. Dynamic regulation of c-Myc proto-oncogene expression during lymphocyte development revealed by a GFP-c-Myc knock-in mouse.

    Science.gov (United States)

    Huang, Ching-Yu; Bredemeyer, Andrea L; Walker, Laura M; Bassing, Craig H; Sleckman, Barry P

    2008-02-01

    c-Myc induces widely varying cellular effects, including cell proliferation and cell death. These different cellular effects are determined, in part, by c-Myc protein expression levels, which are regulated through several transcriptional and post-transcriptional pathways. c-Myc transcripts can be detected in cells at all stages of B and T lymphocyte development. However, little is known about c-Myc protein expression, and how it varies, in developing lymphocytes. Here mice have been generated in which the endogenous c-Myc locus has been modified (c-Myc(G)) so that it encodes a GFP-c-Myc fusion protein. c-Myc(G/G) mice are viable, appear normal and exhibit grossly normal lymphocyte development. Flow cytometric analyses revealed significant heterogeneity in c-Myc protein expression levels in developing c-Myc(G/G) B and T lymphocytes. GFP-c-Myc expression levels were highest in proliferating lymphocytes, suggesting that c-Myc up-regulation is important for promoting lymphocyte cell division, and demonstrating that GFP-c-Myc expression is a marker of proliferating lymphocytes in vivo.

  9. 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

  10. Reversible lysine-specific demethylase 1 antagonist HCI-2509 inhibits growth and decreases c-MYC in castration- and docetaxel-resistant prostate cancer cells.

    Science.gov (United States)

    Gupta, S; Weston, A; Bearrs, J; Thode, T; Neiss, A; Soldi, R; Sharma, S

    2016-12-01

    Lysine-specific demethylase 1 (LSD1 or KDM1A) overexpression correlates with poor survival and castration resistance in prostate cancer. LSD1 is a coregulator of ligand-independent androgen receptor signaling promoting c-MYC expression. We examined the antitumor efficacy of LSD1 inhibition with HCI-2509 in advanced stages of prostate cancer. Cell survival, colony formation, histone methylation, c-MYC level, c-MYC expression, cell cycle changes and in vivo efficacy were studied in castration-resistant prostate cancer cells upon treatment with HCI-2509. In vitro combination studies, using HCI-2509 and docetaxel, were performed to assess the synergy. Cell survival, colony formation, histone methylation and c-myc levels were studied in docetaxel-resistant prostate cancer cells treated with HCI-2509. HCI-2509 is cytotoxic and inhibits colony formation in castration-resistant prostate cancer cells. HCI-2509 treatment causes a dose-dependent increase in H3K9me2 (histone H3lysine 9) levels, a decrease in c-MYC protein, inhibition of c-MYC expression and accumulation in the G0/G1 phase of the cell cycle in these cells. PC3 xenografts in mice have a significant reduction in tumor burden upon treatment with HCI-2509 with no associated myelotoxicity or weight loss. More synergy is noted at sub-IC50 (half-maximal inhibitory concentration) doses of docetaxel and HCI-2509 in PC3 cells than in DU145 cells. HCI-2509 has growth-inhibitory efficacy and decreases the c-myc level in docetaxel-resistant prostate cancer cells. LSD1 inhibition with HCI-2509 decreases the c-MYC level in poorly differentiated prostate cancer cell lines and has a therapeutic potential in castration- and docetaxel-resistant prostate cancer.

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

    Science.gov (United States)

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

    2015-01-01

    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. PMID:26427040

  12. Expression of c-myc oncogene in coeliac disease.

    Science.gov (United States)

    Ciclitira, P J; Stewart, J; Evan, G; Wight, D G; Sikora, K

    1987-01-01

    A monoclonal antibody, produced by peptide immunisation was used to detect the distribution of p62c/myc by immunohistology in normal and coeliac small intestinal mucosa. The effect of gluten in four treated coeliac patients was investigated by taking serial jejunal biopsy specimens for six hours after a 10 g oral gluten challenge. There was a progressive increase in p62c/myc staining intensity in the villus enterocytes extending to the crypts, which accompanied the classical morphological changes occurring in the mucosa. Images Fig 1 Fig 2 PMID:3549790

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

    Directory of Open Access Journals (Sweden)

    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.

  14. Expression of the c-myc oncogene and the presence of HPV 18: possible surrogate markers for cervical cancer?

    Science.gov (United States)

    Rughooputh, S; Manraj, S; Eddoo, R; Greenwell, P

    2009-01-01

    The study aims to evaluate the cause of cervical cancer in a cohort of patients and to establish whether or not human papillomavirus (HPV) is the leading risk factor and to determine whether or not c-myc oncogene over-expression is a predicative marker for the disease. Cone biopsy samples are examined from 53 patients diagnosed with either adenocarcinoma or squamous cell carcinoma of the cervix. Results showed that 19% of the patients studied were positive for high-grade HPV 18 DNA by polymerase chain reaction (PCR). For the c-myc gene expression, only three (23%) of the 13 control slides were positive. Of 49 known cervical cancer patients examined, 41% were positive, 51% were negative and 8% were doubtful. Of those who were positive for HPV, only two were positive for a mutation in the c-myc gene and one slide gave a doubtful result. P value for hysterectomy patients was 0.23 and for cancer patients was 0.48. In the cervical cancer patients studied, the HPV 18 prevalence rate was very low compared to that found in other studies. Therefore, the presence of HPV and expression of the c-myc oncogene cannot be used as surrogate markers for cervical cancer.

  15. Tumor suppressor DYRK1A effects on proliferation and chemoresistance of AML cells by downregulating c-Myc.

    Directory of Open Access Journals (Sweden)

    Qiang Liu

    Full Text Available Acute myeloid leukemia (AML, caused by abnormal proliferation and accumulation of hematopoietic progenitor cells, is one of the most common malignancies in adults. We reported here DYRK1A expression level was reduced in the bone marrow of adult AML patients, comparing to normal controls. Overexpression of DYRK1A inhibited the proliferation of AML cell lines by increasing the proportion of cells undergoing G0/G1 phase. We reasoned that the proliferative inhibition was due to downregulation of c-Myc by DYRK1A, through mediating its degradation. Moreover, overexpression of c-Myc markedly reversed AML cell growth inhibition induced by DYRK1A. DYRK1A also had significantly lower expression in relapsed/refractory AML patients, comparing to newly-diagnosed AML patients, which indicated the role of DYRK1A in chemoresistance of AML. Our study provided functional evidences for DYRK1A as a potential tumor suppressor in AML.

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

    Directory of Open Access Journals (Sweden)

    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.

  17. C-myc oncogene product P62c-myc in ovarian mucinous neoplasms: immunohistochemical study correlated with malignancy.

    Science.gov (United States)

    Polacarz, S V; Hey, N A; Stephenson, T J; Hill, A S

    1989-01-01

    The monoclonal antibody Myc 1-6E10 was used to determine the cellular distribution of the c-myc oncogene product p62c-myc in 60 mucinous ovarian tumours. Three patterns of immunostaining were apparent: (i) nuclear staining alone; (ii) staining of the nucleus and basal cytoplasm; and (iii) staining of the entire cell. Of the 21 cases of mucinous cystadenoma, 11 showed nuclear staining alone, and a further case showed additional weak staining of the basal cytoplasm. Nuclear staining alone was not present in any of the 17 borderline mucinous tumours examined. Strong staining of the nucleus and basal cytoplasm was seen in 16 of these borderline cases, six of which also showed focal staining of the apical cytoplasm. All 22 cases of mucinous cystadenocarcinoma showed staining of the cell nucleus and entire cell cytoplasm. Focal staining of the apical cytoplasm in six of 17 borderline mucinous tumours produced a pattern of c-myc immunostaining similar to that of cystadenocarcinoma. Retrospective analysis of the clinical data showed that no significant differences between patients with borderline tumours of these two categories could be defined. Although immunostaining with Myc 1-6E10 can be used in the categorisation of mucinous ovarian tumours, it is concluded that standard histological criteria are more accurate indicators of tumour behaviour than is an assessment of c-myc expression. Images Fig 1 Fig 2 Fig 3 Fig 4 PMID:2921356

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

    Directory of Open Access Journals (Sweden)

    Sanders Jennifer A

    2012-03-01

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

  19. 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

  20. Expression of c-myc, bcl-2 and survivin in cutaneous and oral ...

    African Journals Online (AJOL)

    Expression of c-myc, bcl-2 and survivin in cutaneous and oral squamous cell carcinoma, basal cell carcinoma and actinic keratosis. ... Conclusion: c-myc expressions correspond to the survivin expressions. c-myc expression was stronger in OSCC than in CSCC and BCC, and weaker in AK than in other malignant tumors.

  1. C-myc oncogene expression in anal squamous neoplasia.

    Science.gov (United States)

    Ogunbiyi, O A; Scholefield, J H; Rogers, K; Sharp, F; Smith, J H; Polacarz, S V

    1993-01-01

    AIMS: To determine the pattern of c-myc oncogene expression in anal squamous neoplasia and to determine if this could be used as a marker of disease progression. METHODS: The presence and localisation of the c-myc gene product p62 in archival specimens of anal squamous epithelium, normal and neoplastic, was examined using immunohistochemical staining with the monoclonal antibody Myc1-6E10. Ten normal and epithelia, 10 anal intraepithelial neoplasia (AIN) III, and 31 anal squamous cancers were examined. RESULTS: There was a noticeable difference between the staining characteristics of invasive tumours, normal anal epithelium, and AIN III. Intense, diffuse, mixed nuclear and cytoplasmic (n = 14) and exclusively nuclear (n = 8) staining in 22 of 31 (71%) of invasive anal tumours was observed. All positively staining tumours were well differentiated histologically, while the negatively staining nine of 31 (29%) were poorly differentiated (n = 7) and moderately well differentiated (n = 2). In six positively staining tumour sections adjacent areas of AIN III and non-dysplastic anal epithelium had staining characteristics similar to those of the invasive component. Staining in both normal anal epithelium (4/10) and AIN III specimens obtained from patients without a history of invasive disease (8/10) was less intense, focal in distribution, and exclusively nuclear. No difference in staining characteristics could be detected in these two groups. CONCLUSIONS: The results of this study suggest that c-myc oncogene expression is implicated in the pathogenesis of anal squamous neoplasia, and that immunohistochemical staining for c-myc protein may be helpful in identifying those AIN III lesions most likely to progress to invasive tumours. Images PMID:7679417

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

    Energy Technology Data Exchange (ETDEWEB)

    Zhi, Xiuyi [Department of Thoracic Surgery, Xuanwu Hospital, Capital Medical University, Beijing, 100053 (China); Giroux-Leprieur, Etienne [ER2 GRC UPMC04 Theranoscan, Pierre et Marie Curie University, Tenon Hospital, 4 Rue de La Chine, 75020, Paris (France); Respiratory Diseases and Thoracic Oncology Department, Ambroise Pare Hospital – APHP, Versailles Saint Quentin en Yvelines University, 9 Avenue Charles de Gaulle, 92100, Boulogne-Billancourt (France); Wislez, Marie [ER2 GRC UPMC04 Theranoscan, Pierre et Marie Curie University, Tenon Hospital, 4 Rue de La Chine, 75020, Paris (France); Hu, Mu; Zhang, Yi [Department of Thoracic Surgery, Xuanwu Hospital, Capital Medical University, Beijing, 100053 (China); Shi, Huaiyin [Department of Pathology, Chinese PLA General Hospital, Fu-xing Road #28, Beijing, 100853 (China); Du, Kaiqi, E-mail: kaiqidu_zhejiang@163.com [Department of Cardiothoracic Surgery, Chinese People' s Armed Police Force, Zhejiang Corps Hospital, Jiaxing, Zhejiang Province (China); Wang, Lei, E-mail: leiwang_hebei@163.com [Department of Human Anatomy, Hebei Medical University, Hebei Province (China)

    2015-10-02

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

  4. [Expression of c-myc protein on rats' brains after brain concussion].

    Science.gov (United States)

    Fang, Wei-Hua; Wang, Dong-Liang; Wang, Feng

    2006-10-15

    To study the changes of expression of c-myc protein on rats' brains after brain concussion. sixty rats were randomly divided into brain concussion groups and control group. The expression of c-myc protein was microscopically observed by immunohistochemical method. No expression of c-myc protein in control group were observed. However, positive expression of c-myc protein in some neurons was seen at 20 min after brain concussion, and reach to the peak at 8h after brain concussion and then decreased gradually. These findings suggest that the detection of c-myc protein could be an index of diagnosis of brain concussion.

  5. Detection of the c-myc oncogene product in testicular cancer.

    OpenAIRE

    Sikora, K; Evan, G; Stewart, J.(DESY, 15738, Zeuthen, Germany); Watson, J. V.

    1985-01-01

    A set of monoclonal antibodies was constructed by immunising mice with peptide fragments of the c-myc oncogene product. One such antibody, Myc 1-6E10 was shown to bind to a 62,000 dalton protein identifiable with the c-myc product (p62c-myc). The antigen recognised was not destroyed by paraffin wax embedding. Myc 1-6E10 was used to characterise the distribution of p62c-myc in archival testicular tumour material. Normal testes expressed only small amounts of p62c-myc. Seminomas showed increase...

  6. Constitutive gray hair in mice induced by melanocyte-specific deletion of c-Myc.

    Science.gov (United States)

    Pshenichnaya, Irina; Schouwey, Karine; Armaro, Marzia; Larue, Lionel; Knoepfler, Paul S; Eisenman, Robert N; Trumpp, Andreas; Delmas, Véronique; Beermann, Friedrich

    2012-05-01

    c-Myc is involved in the control of diverse cellular processes and implicated in the maintenance of different tissues including the neural crest. Here, we report that c-Myc is particularly important for pigment cell development and homeostasis. Targeting c-Myc specifically in the melanocyte lineage using the floxed allele of c-Myc and Tyr::Cre transgenic mice results in a congenital gray hair phenotype. The gray coat color is associated with a reduced number of functional melanocytes in the hair bulb and melanocyte stem cells in the hair bulge. Importantly, the gray phenotype does not progress with time, suggesting that maintenance of the melanocyte through the hair cycle does not involve c-Myc function. In embryos, at E13.5, c-Myc-deficient melanocyte precursors are affected in proliferation in concordance with a reduction in numbers, showing that c-Myc is required for the proper melanocyte development. Interestingly, melanocytes from c-Myc-deficient mice display elevated levels of the c-Myc paralog N-Myc. Double deletion of c-Myc and N-Myc results in nearly complete loss of the residual pigmentation, indicating that N-Myc is capable of compensating for c-Myc loss of function in melanocytes. © 2012 John Wiley & Sons A/S.

  7. Thrombopoietin (TPO) induces c-myc expression through a PI3K- and MAPK-dependent pathway that is not mediated by Akt, PKCzeta or mTOR in TPO-dependent cell lines and primary megakaryocytes.

    Science.gov (United States)

    Chanprasert, Supantitra; Geddis, Amy E; Barroga, Charlene; Fox, Norma E; Kaushansky, Kenneth

    2006-08-01

    Thrombopoietin (TPO) and its receptor (c-Mpl) are the major regulators of megakaryocyte and platelet production and serve a critical and non-redundant role in hematopoietic stem cell (HSC) biology. TPO signals through the Jak-STAT, Ras-Raf-MAPK, and PI3K pathways, and promotes survival, proliferation, and polyploidization in megakaryocytes. The proto-oncogene c-myc also plays an important role in many of these same processes. In this work we studied the regulated expression of c-myc in megakaryocytic cell lines and primary cells by quantitative real-time RT-PCR. We found that TPO induced expression of c-myc in 1 h in both hematopoietic cell lines (UT-7 and BaF3/Mpl) and mature murine megakaryocytes. The TPO-induced expression of c-myc was blocked by a phosphatidylinositol 3-kinase (PI3K) inhibitor, suggesting that TPO stimulated c-myc expression through a PI3K-dependent pathway. Of interest, our study showed that overexpression of active Akt did not rescue the effect of PI3K blockade on c-myc expression, rather, enhanced it. In addition, inhibitors of protein kinase C (PKC)zeta and the target of rapamycin (mTOR) also failed to affect c-myc mRNA expression, while c-myc mRNA expression was reduced by inhibition of the mitogen activated protein kinase (MAPK) pathway. Therefore, we conclude that TPO stimulates c-myc expression in primary megakaryocytes through a PI3K- and MAPK-dependent pathway that is not mediated by Akt, PKCzeta or mTOR.

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

    Science.gov (United States)

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

    2011-01-01

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

  9. 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. Copyright © 2011 UICC.

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

    NARCIS (Netherlands)

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

    2014-01-01

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

  11. The nucleolar ubiquitin-specific protease USP36 deubiquitinates and stabilizes c-Myc

    Science.gov (United States)

    Sun, Xiao-Xin; He, Xia; Yin, Li; Komada, Masayuki; Sears, Rosalie C.; Dai, Mu-Shui

    2015-01-01

    c-Myc protein stability and activity are tightly regulated by the ubiquitin-proteasome system. Aberrant stabilization of c-Myc contributes to many human cancers. c-Myc is ubiquitinated by SCFFbw7 (a SKP1-cullin-1-F-box complex that contains the F-box and WD repeat domain-containing 7, Fbw7, as the F-box protein) and several other ubiquitin ligases, whereas it is deubiquitinated and stabilized by ubiquitin-specific protease (USP) 28. The bulk of c-Myc degradation appears to occur in the nucleolus. However, whether c-Myc is regulated by deubiquitination in the nucleolus is not known. Here, we report that the nucleolar deubiquitinating enzyme USP36 is a novel c-Myc deubiquitinase. USP36 interacts with and deubiquitinates c-Myc in cells and in vitro, leading to the stabilization of c-Myc. This USP36 regulation of c-Myc occurs in the nucleolus. Interestingly, USP36 interacts with the nucleolar Fbw7γ but not the nucleoplasmic Fbw7α. However, it abolished c-Myc degradation mediated both by Fbw7γ and by Fbw7α. Consistently, knockdown of USP36 reduces the levels of c-Myc and suppresses cell proliferation. We further show that USP36 itself is a c-Myc target gene, suggesting that USP36 and c-Myc form a positive feedback regulatory loop. High expression levels of USP36 are found in a subset of human breast and lung cancers. Altogether, these results identified USP36 as a crucial and bono fide deubiquitinating enzyme controlling c-Myc’s nucleolar degradation pathway. PMID:25775507

  12. O-GlcNAc transferase integrates metabolic pathways to regulate the stability of c-MYC in human prostate cancer cells.

    Science.gov (United States)

    Itkonen, Harri M; Minner, Sarah; Guldvik, Ingrid J; Sandmann, Mareike Julia; Tsourlakis, Maria Christina; Berge, Viktor; Svindland, Aud; Schlomm, Thorsten; Mills, Ian G

    2013-08-15

    Metabolic disruptions that occur widely in cancers offer an attractive focus for generalized treatment strategies. The hexosamine biosynthetic pathway (HBP) senses metabolic status and produces an essential substrate for O-linked β-N-acetylglucosamine transferase (OGT), which glycosylates and thereby modulates the function of its target proteins. Here, we report that the HBP is activated in prostate cancer cells and that OGT is a central regulator of c-Myc stability in this setting. HBP genes were overexpressed in human prostate cancers and androgen regulated in cultured human cancer cell lines. Immunohistochemical analysis of human specimens (n = 1987) established that OGT is upregulated at the protein level and that its expression correlates with high Gleason score, pT and pN stages, and biochemical recurrence. RNA interference-mediated siliencing or pharmacologic inhibition of OGT was sufficient to decrease prostate cancer cell growth. Microarray profiling showed that the principal effects of OGT inhibition in prostate cancer cells were related to cell-cycle progression and DNA replication. In particular, c-MYC was identified as a candidate upstream regulator of OGT target genes and OGT inhibition elicited a dose-dependent decrease in the levels of c-MYC protein but not c-MYC mRNA in cell lines. Supporting this relationship, expression of c-MYC and OGT was tightly correlated in human prostate cancer samples (n = 1306). Our findings identify HBP as a modulator of prostate cancer growth and c-MYC as a key target of OGT function in prostate cancer cells.

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

    Science.gov (United States)

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

    2017-01-05

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

  14. [Expression of c-myc and HER-1 genes in the development of human esophageal cancer].

    Science.gov (United States)

    Liang, Y Y

    1991-05-01

    To understand the possible role of oncogenes in the development of human esophageal cancer, the expression of c-myc and HER-1 genes was studied by in situ hybridization. The results showed that: (a) The c-myc and HER-1 protooncogenes were transcriptionally activated (b) Activation of c-myc gene was observed in hyperplastic cells and carcinoma cells. (c) The degree of pathological changes of the esophageal epithelium was related to the level of c-myc transcription, the highest level of c-myc expression was seen in invasive carcinoma cells. (d) Expression of HER-1 gene in carcinoma cells is higher than that in normal and adjacent non-tumor cells, but its frequency is lower than that of c-myc gene.

  15. c-myc oncogene product expression and prognosis in operable breast cancer.

    Science.gov (United States)

    Locker, A. P.; Dowle, C. S.; Ellis, I. O.; Elston, C. W.; Blamey, R. W.; Sikora, K.; Evan, G.; Robins, R. A.

    1989-01-01

    The 62 kDa protein product of the c-myc oncogene (p62 c-myc) is thought to be involved in the control of normal cellular proliferation and differentiation. We have measured oncoprotein levels using a flow cytometric assay in 141 operable breast cancers and have correlated levels with prognostic variables, patient survival and disease free intervals. High levels of p62 c-myc were associated with well differentiated tumours. There was no correlation with tumour DNA index, lymph node or oestrogen receptor status. C-myc oncoprotein levels were not predictive of patient survival or disease free interval. This relationship of oncoprotein levels with tumour histological grade is in keeping with the suggestion that the c-myc oncogene is important in the control of cellular differentiation. The other findings imply that measurement of c-myc oncoprotein levels does not yield useful prognostic information. PMID:2679850

  16. Small Molecules Targeting c-Myc Oncogene: Promising Anti-Cancer Therapeutics

    OpenAIRE

    Chen, Bing-Jia; Wu, Yan-Ling; Tanaka, Yoshimasa; ZHANG, Wen

    2014-01-01

    The nuclear transcription factor c-Myc is a member of the Myc gene family with multiple functions and located on band q24.1 of chromosome 8. The c-Myc gene is activated by chromosomal translocation, rearrangement, and amplification. Its encoded protein transduces intracellular signals to the nucleus, resulting in the regulation of cell proliferation, differentiation, and apoptosis, and has the ability to transform cells and bind chromosomal DNA. c-Myc also plays a critical role in malignant t...

  17. Amplification and expression of a cellular oncogene (c-myc) in human gastric adenocarcinoma cells.

    Science.gov (United States)

    Shibuya, M; Yokota, J; Ueyama, Y

    1985-01-01

    Three of 16 human gastric adenocarcinoma samples, maintained as solid tumors in nude mice, were found to carry amplified c-myc genes. In two samples with a high degree of c-myc DNA amplification (15- to 30-fold), double minute chromosomes were observed in karyotype analysis. The level of c-myc RNA was markedly elevated in a rapidly growing and poorly differentiated tumor, whereas it was only slightly elevated in a slowly growing and more differentiated tumor. Images PMID:2579323

  18. c-myc, c-fos, and c-jun regulation in the regenerating livers of normal and H-2K/c-myc transgenic mice.

    OpenAIRE

    Morello, D; Fitzgerald, M J; Babinet, C; Fausto, N

    1990-01-01

    We investigated the mechanisms of regulation of c-myc, c-fos, and c-jun at the early stages of liver regeneration in mice. We show that the transient increase in steady-state levels of c-myc mRNA at the start of liver regeneration is most probably regulated by posttranscriptional mechanisms. Although there was a marked increase in c-myc transcriptional initiation shortly after partial hepatectomy, a block in elongation prevented the completion of most transcripts. To gain further information ...

  19. Growth-promoting and tumourigenic activity of c-Myc is suppressed by Hhex.

    Science.gov (United States)

    Marfil, V; Blazquez, M; Serrano, F; Castell, J V; Bort, R

    2015-06-04

    c-Myc transcription factor is a key protein involved in cellular growth, proliferation and metabolism. c-Myc is one of the most frequently activated oncogenes, highlighting the need to identify intracellular molecules that interact directly with c-Myc to suppress its function. Here we show that Hhex is able to interact with the basic region/helix-loop-helix/leucine zipper of c-Myc. Knockdown of Hhex increases proliferation rate in hepatocellular carcinoma cells, whereas Hhex expression cell-autonomously reduces cell proliferation rate in multiple cell lines by increasing G1 phase length through a c-Myc-dependent mechanism. Global transcriptomic analysis shows that Hhex counter-regulates multiple c-Myc targets involved in cell proliferation and metabolism. Concomitantly, Hhex expression leads to reduced cell size, lower levels of cellular RNA, downregulation of metabolism-related genes, decreased sensitivity to methotrexate and severe reduction in the ability to form tumours in nude mouse xenografts, all indicative of decreased c-Myc activity. Our data suggest that Hhex is a novel regulator of c-Myc function that limits c-Myc activity in transformed cells.

  20. Elevated c-myc protooncogene expression in autosomal recessive polycystic kidney disease

    Energy Technology Data Exchange (ETDEWEB)

    Cowley, B.D. Jr.; Smardo, F.L. Jr.; Grantham, J.J.; Calvet, J.P.

    1987-12-01

    The polycystic kidney diseases (PKDs) are a group of disorders characterized by the growth of epithelial cysts from the nephrons and collecting ducts of kidney tubules. The diseases can be inherited or can be provoked by environmental factors. To investigate the molecular basis of the abnormal cell growth associated with PKD, c-myc protooncogene expression was studied in a mouse model for autosomal recessive PKD. Homozygous recessive C57BL/6J (cpk/cpk) mice develop massively enlarged cystic kidneys and die from renal failure shortly after 3 weeks of age. Quantitative dot blot and RNA blot hybridization experiments in which whole kidney poly(A)/sup +/ RNA was hybridized with a c-myc RNA probe showed a 2- to 6-fold increase in c-myc mRNA at 2 weeks, and a 25- to 30-fold increase in c-myc mRNA at 3 weeks of age in polycystic mice, as compared to normal littermates. c-myc expression was also examined under two conditions in which kidney cell growth was experimentally induced in normal adult mice: compensatory renal hypertrophy and tubule regeneration following folic acid-induced renal cell injury. While compensatory hypertrophy resulted in only a small increase in c-myc, folic acid treatment gave rise after 24 hr to a 12-fold increase in c-myc RNA. The induction of c-myc by folic acid is consistent with increased cellular proliferation regenerating tubules. In contrast, polycystic kidneys show only a minimal increase in cellular proliferation over that seen in normal kidneys, while c-myc levels were found to be markedly elevated. Thus, the level of c-myc expression in cystic kidneys appears to be out of proportion to the rate of cell division, suggesting that elevated and potentially abnormal c-myc expression may be involved in the pathogenesis of PKD.

  1. Upregulation of the oncogene c-myc in Barrett’s adenocarcinoma: induction of c-myc by acidified bile acid in vitro

    Science.gov (United States)

    Tselepis, C; Morris, C D; Wakelin, D; Hardy, R; Perry, I; Luong, Q T; Harper, E; Harrison, R; Attwood, S E A; Jankowski, J A Z

    2003-01-01

    Background and aims: C-myc over expression is implicated in malignancy although to date this has not been studied in Barrett’s metaplasia. We sought to determine c-myc expression in the malignant progression of Barrett’s metaplasia and whether it may be induced by bile acids seen in gastro-oesophageal refluxate. Methods: C-myc protein and mRNA levels were assessed in 20 Barrett’s metaplasia and 20 oesophageal adenocarcinoma samples by western blotting and real time polymerase chain reaction. Levels of c-myc and proliferation were also assessed in cell lines OE21, OE33, SW-480, and TE-7 stimulated with pulses or continuous exposure to the bile acids deoxycholic acid and chenodeoxycholic acid. Results: C-myc protein was upregulated in 50% of Barrett’s metaplasia and 90% of oesophageal adenocarcinoma samples compared with squamous, gastric, and duodenal controls. C-myc immunolocalisation in Barrett’s metaplasia revealed discrete nuclear localisation, becoming more diffuse with progression from low to high grade dysplasia to adenocarcinoma. Both continual and pulsed bile acid induced c-myc at pH 4, with no effect at pH 7 or with acidified media alone. Pulsed bile acid treatment induced proliferation (p<0.05); in contrast, continuous exposure led to suppression of proliferation (p<0.05). Conclusions: We have shown upregulation of c-myc with malignant progression of Barrett’s metaplasia and suggest that acidified bile may be a novel agent responsible for induction of this oncogene. PMID:12524396

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

    Science.gov (United States)

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

    2015-12-21

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

  3. 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.

  4. B Lymphocyte commitment program is driven by the proto-oncogene c-Myc.

    Science.gov (United States)

    Vallespinós, Mireia; Fernández, David; Rodríguez, Lorena; Alvaro-Blanco, Josué; Baena, Esther; Ortiz, Maitane; Dukovska, Daniela; Martínez, Dolores; Rojas, Ana; Campanero, Miguel R; Moreno de Alborán, Ignacio

    2011-06-15

    c-Myc, a member of the Myc family of transcription factors, is involved in numerous biological functions including the regulation of cell proliferation, differentiation, and apoptosis in various cell types. Of all of its functions, the role of c-Myc in cell differentiation is one of the least understood. We addressed the role of c-Myc in B lymphocyte differentiation. We found that c-Myc is essential from early stages of B lymphocyte differentiation in vivo and regulates this process by providing B cell identity via direct transcriptional regulation of the ebf-1 gene. Our data show that c-Myc influences early B lymphocyte differentiation by promoting activation of B cell identity genes, thus linking this transcription factor to the EBF-1/Pax-5 pathway.

  5. The translocated c-myc oncogene of Raji Burkitt lymphoma cells is not expressed in human lymphoblastoid cells.

    Science.gov (United States)

    Nishikura, K; Erikson, J; ar-Rushdi, A; Huebner, K; Croce, C M

    1985-01-01

    We hybridized Raji Burkitt lymphoma cells, which carry a t(8;14) chromosome translocation, with human lymphoblastoid cells to study the expression of the translocated cellular myc oncogene (c-myc) in the hybrid cells. In Raji cells the c-myc oncogene is translocated to a switch region of the gamma heavy chain locus (S gamma). Because of sequence alterations in the 5' exon of the translocated c-myc oncogene in this cell line, it is possible to distinguish the transcripts of the translocated c-myc gene and of the normal c-myc gene. S1 nuclease protection experiments with a c-myc first exon probe indicate that Raji cells express predominantly the translocated c-myc gene, while the level of expression of the normal c-myc gene is less than 2% of that of the translocated c-myc gene. Somatic cell hybrids between Raji and human lymphoblastoid cells retain the lymphoblastoid phenotype and express only the normal c-myc oncogene. This result indicates that the activation of a c-myc oncogene translocated to a S region depends on the stage of B-cell differentiation of the cells harboring the translocated c-myc gene and not on alterations in the structure of the translocated c-myc oncogene. Images PMID:3857623

  6. MicroRNA-451 induces epithelial-mesenchymal transition in docetaxel-resistant lung adenocarcinoma cells by targeting proto-oncogene c-Myc.

    Science.gov (United States)

    Chen, Dongqin; Huang, Jiayuan; Zhang, Kai; Pan, Banzhou; Chen, Jing; De, Wei; Wang, Rui; Chen, Longbang

    2014-11-01

    Epithelial-mesenchymal transition (EMT) has been reported to play a significant role in tumour metastasis as well as chemoresistance. However, the molecular mechanisms involved in chemotherapy-induced EMT are still unclear. MicroRNA (miRNA) expression and functions have been reported to contribute to phenotypic features of tumour cells. To investigate the roles of miRNAs in chemotherapy-induced EMT, we established two docetaxel-resistant lung adenocarcinoma (LAD) cell models (SPC-A1/DTX and H1299/DTX), which display EMT-like properties and gain increased invasion or migration activity. MiR-451 was found to be significantly downregulated in docetaxel-resistant LAD cells, and re-expression of miR-451 could reverse EMT to mesenchymal-epithelial transition (MET) and inhibit invasion and metastasis of docetaxel-resistant LAD cells both in vitro and in vivo. The proto-oncogene c-Myc was identified as a direct and functional target of miR-451, and further researches confirmed that overexpression of c-Myc which induced extracellular-signal-regulated kinase (ERK)-dependent glycogen synthase kinase-3 beta (GSK-3β) inactivation and subsequent snail activation is essential for acquisition of EMT phenotype induced by loss of miR-451. Furthermore, c-Myc was significantly upregulated in docetaxel-non-responding LAD tissues in comparison with docetaxel-responding tissues, and its expression was inversely correlated with miR-451 expression. This study first reported the involvement of miR-451/c-Myc/ERK/GSK-3β signalling axis in the acquisition of EMT phenotype in docetaxel-resistant LAD cells, suggesting that re-expression of miR-451 or targeting c-Myc will be a potential strategy for the treatment of chemoresistant LAD patients. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Detection of the c-myc oncogene product in testicular cancer.

    Science.gov (United States)

    Sikora, K.; Evan, G.; Stewart, J.; Watson, J. V.

    1985-01-01

    A set of monoclonal antibodies was constructed by immunising mice with peptide fragments of the c-myc oncogene product. One such antibody, Myc 1-6E10 was shown to bind to a 62,000 dalton protein identifiable with the c-myc product (p62c-myc). The antigen recognised was not destroyed by paraffin wax embedding. Myc 1-6E10 was used to characterise the distribution of p62c-myc in archival testicular tumour material. Normal testes expressed only small amounts of p62c-myc. Seminomas showed increased nuclear and cytoplasmic staining. Undifferentiated teratoma showed little activity, whereas p62c-myc was abundant in the nuclei of differentiating epithelial structures, yolk sacs and embryoid bodies. Only small amounts of p62c-myc were seen in the tumours of 5 patients who subsequently died from their disease. Images Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 PMID:4027160

  8. The proto-oncogene c-myc regulates antibody secretion and Ig class switch recombination.

    Science.gov (United States)

    Fernández, David; Ortiz, Maitane; Rodríguez, Lorena; García, Arancha; Martinez, Dolores; Moreno de Alborán, Ignacio

    2013-06-15

    The immune response involves the generation of Ab-secreting cells and memory B cells through a process called terminal B lymphocyte differentiation. This program requires the transcriptional repressor Blimp-1, which inhibits c-myc expression and terminates proliferation. Although the role of c-Myc in cell proliferation is well characterized, it is not known whether it has other functions in terminal differentiation. In this study, we show that c-Myc not only regulates cell proliferation, but it is also essential for Ab-secreting cell function and differentiation in vivo. c-Myc-deficient B lymphocytes hypersecrete IgM and do not undergo Ig class switch recombination (CSR). CSR has been previously linked to proliferation, and in this study we mechanistically link class switching and proliferation via c-Myc. We observed that c-Myc regulates CSR by transcriptionally activating the B cell-specific factor activation-induced cytidine deaminase. By linking cell proliferation and CSR, c-Myc is thus a critical component for a potent immune response.

  9. Translocation of an immunoglobulin kappa locus to a region 3' of an unrearranged c-myc oncogene enhances c-myc transcription.

    Science.gov (United States)

    Erikson, J; Nishikura, K; ar-Rushdi, A; Finan, J; Emanuel, B; Lenoir, G; Nowell, P C; Croce, C M

    1983-01-01

    We have studied somatic cell hybrids between mouse myeloma and JI Burkitt lymphoma cells carrying a t(2;8) chromosome translocation for the expression of human kappa chains. and for the presence and rearrangements of the human c-myc oncogene and kappa chain genes. Our results indicate that the c-myc oncogene is unrearranged and remains on the 8q+ chromosome of JI cells. Two rearranged C kappa genes were detected: the expressed allele on normal chromosome 2 and the excluded kappa allele that was translocated from chromosome 2 to the involved chromosome 8 (8q+). The distribution of V kappa and C kappa genes in hybrid clones retaining different human chromosomes indicated that C kappa is distal to V kappa on 2p and that the breakpoint in this Burkitt lymphoma is within the region carrying V kappa genes. High levels of transcripts of the c-myc gene were found when it resided on the 8q+ chromosome but not on the normal chromosome 8, demonstrating that translocation of a kappa locus to region distal to the c-myc oncogene enhances c-myc transcription. Images PMID:6424112

  10. 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.

  11. Specific regulation of c-myc oncogene expression in a murine B-cell lymphoma.

    Science.gov (United States)

    McCormack, J E; Pepe, V H; Kent, R B; Dean, M; Marshak-Rothstein, A; Sonenshein, G E

    1984-01-01

    The c-myc oncogene has been implicated in a wide spectrum of B-cell neoplasias. In normal cells, the level of expression of the c-myc gene correlates with growth status. In the present study, we examined the effect of receptor-mediated inhibition of growth on c-myc expression in a B-cell lymphoma. The murine lymphoma line WEHI 231 has been characterized as an early B cell; it bears surface-bound IgM and has unrearranged c-myc genes. Following treatment of a WEHI 231 culture with anti-mouse Ig antiserum, the cells undergo one round of division and further proliferation is inhibited. We observed that this treatment specifically affected cytoplasmic levels of c-myc mRNA. An initial early increase is followed by a precipitous drop such that by 4 hr (after exposure) the amount of c-myc mRNA is below control values by a factor of approximately equal to 10. The drop in c-myc precedes cessation of DNA synthesis. During the 2- to 4-hr period, c-myc mRNA had a maximal half-life of between 20 and 30 min. In contrast, even 24 hr after anti-Ig exposure, the amounts of most major mRNAs, including mu heavy chain and actin, were not significantly altered. These results indicate that expression of an unrearranged c-myc gene can be selectively responsive to receptor-mediated regulatory events. Images PMID:6206500

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

    Directory of Open Access Journals (Sweden)

    Liao Dezhong J

    2008-01-01

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

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

    Science.gov (United States)

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

    2008-01-24

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

  14. A cyclometallated iridium(III) complex as a c-myc G-quadruplex stabilizer and down-regulator of c-myc oncogene expression.

    Science.gov (United States)

    Yang, H; Ma, V P-Y; Chan, D S-H; He, H-Z; Leung, C-H; Ma, D-L

    2013-01-01

    A new cyclometallated iridium(III) complex with the 2,2'-biquinoline N-donor ligand has been synthesized and characterized. The interaction and affinity of the complex towards c-myc G-quadruplex and duplex DNA have been investigated using UV/Vis spectroscopy and gel mobility shift assay. These studies revealed that complex 1 binds to c-myc G-quadruplexes (Pu22 and Pu27) with high affinity but does not interact with duplex DNA either by intercalation or groove binding. The ability of 1 to stabilize c-myc G-quadruplex DNA in vitro has also been examined through a PCR stop assay and a cell-based luciferase reporter assay. Complex 1 displays promising cytotoxic activity against the HeLa cell line with sub-micromolar potency.

  15. Antiproliferative effects of antisense oligonucleotides directed to the RNA of c-myc oncogene.

    Science.gov (United States)

    Degols, G; Leonetti, J P; Mechti, N; Lebleu, B

    1991-01-01

    Several groups have reported the use of antisense oligonucleotides to inhibit c-myc gene expression and study its biological role. However high concentrations of free oligonucleotides were generally needed. To lower their concentration and stabilize the antisense effect against c-myc, oligonucleotides were covalently linked to poly(L-lysine) and administered in ternary complexes formed with heparin (100 micrograms/ml). A sequence specific growth inhibition was observed at concentrations lower than 1 microM, while oligonucleotide-poly(L-lysine) conjugates alone were inefficient. Similar results occurred with other polyanionic compounds. Inhibition of proliferation was correlated to a reduction of c-myc protein and to a transient decrease in c-myc mRNA level. However, implication of RNase H in this process could not be demonstrated. Images PMID:1708128

  16. UV damage and repair in the domain of the human c-myc oncogene

    Energy Technology Data Exchange (ETDEWEB)

    Bianchi, N.O.; Bianchi, M.S.; Alitalo, K.; De La Chapelle, A. (IMBICE, La Plata (Argentina))

    1991-03-01

    We have used a modification of the Southern hybridization method to analyze the removal of UV-induced pyrimidine cyclobutane dimers from the domain of the c-myc oncogene. The study was performed in human COLO320HSR cells, which exhibit a 30- to 40-fold amplification of c-myc that is maintained in a marker chromosome as a homogeneously staining region. Intron 2 and the region upstream from the gene showed better dimer removal than intron 1 or the region downstream from the c-myc gene. Regions showing less repair coincide with regions that are hotspots for mutations and chromosome translocations. Therefore, it is proposed that the inefficiency of DNA repair may play an important role in the origin of c-myc rearrangements.

  17. Astroglial networks promote neuronal coordination.

    Science.gov (United States)

    Chever, Oana; Dossi, Elena; Pannasch, Ulrike; Derangeon, Mickael; Rouach, Nathalie

    2016-01-12

    Astrocytes interact with neurons to regulate network activity. Although the gap junction subunits connexin 30 and connexin 43 mediate the formation of extensive astroglial networks that cover large functional neuronal territories, their role in neuronal synchronization remains unknown. Using connexin 30- and connexin 43-deficient mice, we showed that astroglial networks promoted sustained population bursts in hippocampal slices by setting the basal active state of neurons. Astroglial networks limited excessive neuronal depolarization induced by spontaneous synaptic activity, increased neuronal release probability, and favored the recruitment of neurons during bursting, thus promoting the coordinated activation of neuronal networks. In vivo, this sustained neuronal coordination translated into increased severity of acutely evoked epileptiform events and convulsive behavior. These results revealed that connexin-mediated astroglial networks synchronize bursting of neuronal assemblies, which can exacerbate pathological network activity and associated behavior. Our data thus provide molecular and biophysical evidence predicting selective astroglial gap junction inhibitors as anticonvulsive drugs. Copyright © 2016, American Association for the Advancement of Science.

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

    Indian Academy of Sciences (India)

    SAMIRA SADEGHI

    and c-myc in breast tumours collected from breast cancer patients of the Iranian population. EpCAM .... Type. Fibroadenoma. 1. 9. 10. 2. 8. 10. Ductal or lobular hyperplasia. 0. 3. 3. 1. 2. 3. Lobular carcinoma in situ. 1. 4. 5. 2. 3. 5. Total. 2. 16. 18. 5. 13. 18. Age. 50<. 2. 12 ..... Distribution of EpCAM/c-myc positive and negative.

  19. Arf tumor suppressor disrupts the oncogenic positive feedback loop including c-Myc and DDX5.

    Science.gov (United States)

    Tago, K; Funakoshi-Tago, M; Itoh, H; Furukawa, Y; Kikuchi, J; Kato, T; Suzuki, K; Yanagisawa, K

    2015-01-15

    Tumor suppressor protein p19(ARF) (Arf; p14(ARF) in humans) functions in both p53-dependent and -independent modes to counteract hyper-proliferative signals caused by proto-oncogene activation, but its p53-independent activities remain poorly understood. Using the tandem affinity purification-tag technique, we purified Arf-containing protein complexes and identified p68 DEAD-box protein (DDX5) as a novel interacting protein of Arf. In this study, we found that DDX5 interacts with c-Myc, and harbors essential roles for c-Myc-mediated transcription and its transforming activity. Furthermore, when c-Myc was forcibly expressed, the expression level of DDX5 protein was drastically increased through the acceleration of protein synthesis of DDX5, suggesting the presence of an oncogenic positive feedback loop including c-Myc and DDX5. Strikingly, Arf blocked the physical interaction between DDX5 and c-Myc, and drove away DDX5 from the promoter of c-Myc target genes. These observations most likely indicate the mechanism by which Arf causes p53-independent tumor-suppressive activity.

  20. Posttranscriptional regulation of cellular gene expression by the c-myc oncogene

    Energy Technology Data Exchange (ETDEWEB)

    Prendergast, G.C.; Cole, M.D. (Princeton Univ., NJ (USA). Dept. of Biology)

    1989-01-01

    The c-myc oncogene has been implicated in the development of many different cancers, yet the mechanism by which the c-myc protein alters cellular growth control has proven elusive. The authors used a cDNA hybridization difference assay to isolate two genes, mr1 and mr2, that were constitutively expressed (i.e., deregulated) in rodent fibroblast cell lines immortalized by transfection of a viral promoter-linked c-myc gene. Both cDNAs were serum inducible in quiescent G/sub o/ fibroblasts, suggesting that they are functionally related to cellular proliferative processes. Although there were significant differences in cytoplasmic mRNA levels between myc-immortalized and control cells, the rates of transcription and mRNA turnover of both genes were similar, suggesting that c-myc regulates mr1 and mr2 expression by some nuclear posttranscriptional mechanism. Their results provide evidence that c-myc can rapidly modulate cellular gene expression and suggest that c-myc may function in gene regulation at the level of RNA export, splicing, or nuclear RNA turnover.

  1. Structure-based design of flavone derivatives as c-myc oncogene down-regulators.

    Science.gov (United States)

    Yang, Hui; Zhong, Hai-Jing; Leung, Ka-Ho; Chan, Daniel Shiu-Hin; Ma, Victor Pui-Yan; Fu, Wai-Chung; Nanjunda, Rupesh; Wilson, W David; Ma, Dik-Lung; Leung, Chung-Hang

    2013-01-23

    Based on molecular docking analysis of complexes between flavone and the c-myc G-quadruplex, we designed and screened 30 flavone derivatives containing various side chains that could potentially form interactions with the G-quadruplex grooves. As a proof-of-concept, the highest-scoring flavone derivatives containing cationic pyridinium side chains were synthesized and their interactions with the c-myc G-quadruplex were examined using a PCR-stop assay. The stabilizing effects of the flavone derivatives were found to be selective towards the c-myc G-quadruplex over other biologically relevant G-quadruplex structures, such as the human telomeric sequence (HTS). The interaction between the most potent compound of the series and the c-myc G-quadruplex was examined in depth using UV-Vis titration, molecular modeling and CD spectroscopy. Our results suggest that in addition to stabilizing the c-myc G-quadruplex, the flavone derivatives were capable of inducing the formation of the G-quadruplex structure even in the absence of monovalent cations. The flavone derivatives were found to be potent inhibitors of c-myc promoters within the cellular environment and displayed promising cytotoxic behavior against human cancer cell lines. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. The c-myc oncogene is translocated to the involved chromosome 12 in mouse plasmacytoma.

    Science.gov (United States)

    Erikson, J; Miller, D A; Miller, O J; Abcarian, P W; Skurla, R M; Mushinski, J F; Croce, C M

    1985-01-01

    Although it is known that the c-myc oncogene is rearranged in a head-to-head fashion with the immunoglobulin heavy chain locus in mouse plasmacytomas, it has not been clear whether the c-myc oncogene is translocated to the heavy chain locus on mouse chromosome 12 or whether the heavy chain locus is translocated to the c-myc locus on mouse chromosome 15. To determine which of these two possibilities is correct, we hybridized Chinese hamster fibroblasts with J558 mouse plasmacytoma cells that carry a reciprocal chromosome translocation between chromosomes 12 and 15, and we examined the segregating hybrids for the presence of the normal and rearranged mouse c-myc genes, for the presence of different regions of the mouse heavy chain locus, and for the presence of genes located on mouse chromosomes 12 and 15. The results of this analysis indicate that, as in human Burkitt lymphomas with the 8;14 chromosome translocation, the c-myc gene is translocated to the heavy chain locus in mouse plasmacytomas. Thus the orientation of the heavy chain locus on mouse chromosome 12 and of the c-myc gene on mouse chromosome 15 is the same as the orientation of the homologous loci in man. Images PMID:3923490

  3. Detection of the c-myc oncogene product in colonic polyps and carcinomas.

    Science.gov (United States)

    Stewart, J.; Evan, G.; Watson, J.; Sikora, K.

    1986-01-01

    The c-myc oncogene has been implicated in the processes of normal cell proliferation and differentiation. Elevated levels of c-myc mRNA and its gene product (p62c-myc), have been detected in a variety of solid tumours and cultured cel lines. Its precise role in normal cell function and in neoplastic transformation and progression has yet to be elucidated. We have used a monoclonal antibody, raised by peptide immunisation, to determine the distribution by immunoperoxidase staining of the c-myc oncogene product in archival specimens of colonic polyps and carcinomas. Samples from 42 patients with colon carcinoma, 24 with benign polyps and 15 normal colon biopsies were examined. Normal colon revealed maximum staining in the mid-zone of the crypts, corresponding to the zone of differentiation and maturation. The staining was predominantly cytoplasmic. Adenomatous polyps revealed the most intense pattern of staining in areas of dysplastic change. Colonic tumours showed a wide range of staining. Well differentiated tumours contained more cytoplasmic p62c-myc than poorly differentiated tumours. These findings suggest that the c-myc oncogene product may play an important role in the evolution of colonic neoplasia. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:3511934

  4. c-MYC-Induced Sebaceous Gland Differentiation Is Controlled by an Androgen Receptor/p53 Axis

    Directory of Open Access Journals (Sweden)

    Denny L. Cottle

    2013-02-01

    Full Text Available Although the sebaceous gland (SG plays an important role in skin function, the mechanisms regulating SG differentiation and carcinoma formation are poorly understood. We previously reported that c-MYC overexpression stimulates SG differentiation. We now demonstrate roles for the androgen receptor (AR and p53. MYC-induced SG differentiation was reduced in mice lacking a functional AR. High levels of MYC triggered a p53-dependent DNA damage response, leading to accumulation of proliferative SG progenitors and inhibition of AR signaling. Conversely, testosterone treatment or p53 deletion activated AR signaling and restored MYC-induced differentiation. Poorly differentiated human sebaceous carcinomas exhibited high p53 and low AR expression. Thus, the consequences of overactivating MYC in the SG depend on whether AR or p53 is activated, as they form a regulatory axis controlling proliferation and differentiation.

  5. DNA Methylation Mediated Downregulation of miR-449c Controls Osteosarcoma Cell Cycle Progression by Directly Targeting Oncogene c-Myc.

    Science.gov (United States)

    Li, Qing; Li, Hua; Zhao, Xueling; Wang, Bing; Zhang, Lin; Zhang, Caiguo; Zhang, Fan

    2017-01-01

    MicroRNAs (miRNAs) are critical regulators of gene expression, and they have broad roles in the pathogenesis of different diseases including cancer. Limited studies and expression profiles of miRNAs are available in human osteosarcoma cells. By applying a miRNA microarray analysis, we observed a number of miRNAs with abnormal expression in cancerous tissues from osteosarcoma patients. Of particular interest in this study was miR-449c, which was significantly downregulated in osteosarcoma cells and patients, and its expression was negatively correlated with tumor size and tumor MSTS stages. Ectopic expression of miR-449c significantly inhibited osteosarcoma cell proliferation and colony formation ability, and caused cell cycle arrest at the G1 phase. Further analysis identified that miR-449c was able to directly target the oncogene c-Myc and negatively regulated its expression. Overexpression of c-Myc partially reversed miR-449c-mimic-inhibited cell proliferation and colony formation. Moreover, DNA hypermethylation was observed in two CpG islands adjacent to the genomic locus of miR-449c in osteosarcoma cells. Conversely, treatment with the DNA methylation inhibitor AZA caused induction of miR-449c. In conclusion, our results support a model that DNA methylation mediates downregulation of miR-449c, diminishing miR-449c mediated inhibition of c-Myc and thus leading to the activation of downstream targets, eventually contributing to osteosarcoma tumorigenesis.

  6. 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. Copyright © 2014 Elsevier B.V. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-02-15

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

  8. 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.

  9. Chromosome translocation activates heterogeneously initiated, bipolar transcription of a mouse c-myc gene.

    Science.gov (United States)

    Calabi, F; Neuberger, M S

    1985-01-01

    In many mouse plasmacytomas, the active c-myc gene has been truncated by chromosome translocation with the resultant severance of the protein-coding sequence from the normal promoter. Transcripts of such truncated c-myc genes were analyzed by Northern blotting, nuclease S1 mapping, primer extension assays and cDNA cloning. We conclude that transcription originates from multiple initiation sites on both c-myc coding and non-coding strands with the two-sets of transcripts derived from adjacent but essentially non-overlapping regions located greater than 1 kb from the translocation junction. In X63Ag8, where c-myc is translocated to the immunoglobulin C gamma 2b gene, the c-myc non-coding strand transcripts include the translocation junction and then splice directly into the gamma 2b CH1 exon. We propose that chromosome translocation activates a cryptic promoter in the first intron and that the heterogeneously initiated, bipolar transcription reflects the absence of a suitably placed TATA box element. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 7. Fig. 8. PMID:3924591

  10. "Retroposon" insertion into the cellular oncogene c-myc in canine transmissible venereal tumor.

    Science.gov (United States)

    Katzir, N; Rechavi, G; Cohen, J B; Unger, T; Simoni, F; Segal, S; Cohen, D; Givol, D

    1985-01-01

    We examined by Southern blotting the state of the cellular oncogene c-myc in the dog transmissible venereal tumor. The tumor DNA contains a 16.8-kilobase pair (kbp) rearranged c-myc fragment in addition to the normal 15-kbp and 7.5-kbp fragments. We compared the structure of the cloned rearranged c-myc (re-myc) with that of a cloned normal c-myc and found that the rearrangement was due to the insertion of a 1.8-kbp DNA upstream to the first exon of c-myc. The inserted DNA is flanked by 10-base-pair direct repeats and contains a dA-rich tail, suggesting its origin from mRNA. Partial sequence of the inserted element showed 62% homology with the primate interdispersed Kpn I repetitive element. These results provide an example for the behavior of repetitive DNA sequences like the Kpn I family, as movable elements that can transpose nearby to oncogenes or other structural genes and perhaps affect their activity. Images PMID:2983328

  11. The structure and nucleotide sequence of the 5' end of the human c-myc oncogene.

    Science.gov (United States)

    Watt, R; Nishikura, K; Sorrentino, J; ar-Rushdi, A; Croce, C M; Rovera, G

    1983-01-01

    We have established the structure and nucleotide sequence of the 5' end of the human c-myc oncogene, using a cloned genomic fragment isolated from a fetal liver library (clone lambda MC41) and cloned cDNA from the human leukemic cell line K562. The human c-myc oncogene consists of three exons and two introns. Primer extension of the human c-myc mRNA of three different cell lines and S1 nuclease protection experiments served to establish the position of two transcription initiation sites. The splicing site of the first exon-intron boundary was determined by comparative analysis of the sequences of the genomic and cDNA clones. The first exon contains termination codons in all three reading frames and no translation initiation signals, confirming our previous observation that the c-myc mRNA has a long 5' noncoding sequence. This first exon also was found to be utilized in the formation of c-myc mRNAs in a variety of human cell lines. Images PMID:6578511

  12. Discovery of a natural product-like c-myc G-quadruplex DNA groove-binder by molecular docking.

    Directory of Open Access Journals (Sweden)

    Dik-Lung Ma

    Full Text Available The natural product-like carbamide (1 has been identified as a stabilizer of the c-myc G-quadruplex through high-throughput virtual screening. NMR and molecular modeling experiments revealed a groove-binding mode for 1. The biological activity of 1 against the c-myc G-quadruplex was confirmed by its ability to inhibit Taq polymerase-mediated DNA extension and c-myc expression in vitro, demonstrating that 1 is able to control c-myc gene expression at the transcriptional level presumably through the stabilization of the c-myc promoter G-quadruplex. Furthermore, the interaction between carbamide analogues and the c-myc G-quadruplex was also investigated by in vitro experiments in order to generate a brief structure-activity relationship (SAR for the observed potency of carbamide 1.

  13. Acetylation of the c-MYC oncoprotein is required for cooperation with the HTLV-1 p30II accessory protein and the induction of oncogenic cellular transformation by p30II/c-MYC

    Science.gov (United States)

    Romeo, Megan M.; Ko, Bookyung; Kim, Janice; Brady, Rebecca; Heatley, Hayley C.; He, Jeffrey; Harrod, Carolyn K.; Barnett, Braden; Ratner, Lee; Lairmore, Michael D.; Martinez, Ernest; Lüscher, Bernhard; Robson, Craig N.; Henriksson, Marie; Harrod, Robert

    2014-01-01

    The human T-cell leukemia retrovirus type-1 (HTLV-1) p30II 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 p30II 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 p30II and c-MYC remain to be completely understood. Herein we demonstrate that p30II induces lysine-acetylation of the c-MYC oncoprotein. Acetylation-defective c-MYC Lys→Arg substitution mutants are impaired for oncogenic transformation with p30II in c-myc−/− HO15.19 fibroblasts. Using dual-chromatin-immunoprecipitations (dual-ChIPs), we further demonstrate that p30II is present in c-MYC-containing nucleoprotein complexes in HTLV-1-transformed HuT-102 T-lymphocytes. Moreover, p30II 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 p30II/c-MYC which could promote proviral replication and contribute to HTLV-1-induced carcinogenesis. PMID:25569455

  14. c-Myc-induced transcription factor AP4 is required for CD8+ T cell-mediated host protection

    OpenAIRE

    Chou, Chun; Pinto, Amelia K.; Curtis, Jonathan D.; Persaud, Stephen P.; Cella, Marina; Lin, Chih-Chung; Edelson, Brian T.; Allen, Paul M.; Colonna, Marco; Pearce, Erika L; Diamond, Michael S.; Egawa, Takeshi

    2014-01-01

    Although c-Myc is essential to establish a metabolically active and proliferative state in T cells after priming, its expression is transient. It remains unknown how T cell activation is maintained after c-Myc down-regulation. Here, we identify AP4 as the transcription factor that is induced by c-Myc and sustains activation of antigen-specific CD8+ T cells. Despite normal priming, AP4-deficient CD8+ T cells fail to continue transcription of a broad range of c-Myc-dependent targets. Mice lacki...

  15. 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.

  16. [Advances Research on C-MYC Proto-oncogene in Multiple Myeloma -Review].

    Science.gov (United States)

    Huang, He; Guo, Wen-Jian; Yao, Ron-Xin

    2016-08-01

    Multiple myeloma(MM) as one of the most common tumors of hmatologic system, is characterized by malignant proliferation of plasma cells, and the chemotherapy is the main therapeutic method. MM is an incurable disease because of drug-resistance of MM cells. Although the pathogenesis of MM remains unknown, the chromosome abnormalities exit in half of the patients, particularly the highly expressed gene C-MYC. Furthermore, plenty of clinical researches indicated a high expression level of C-MYC implied worse progression and/or poor prognosis of MM. Recently, the work exploiting the compounds targeting MYC has made substantial progress, even in the MM therapy. In this article, briefly the recent advances of the research on C-MYC proto-oncogene in multiple myeloma are reviewed.

  17. Transactivation of proto-oncogene c-Myc by hepatitis B virus transactivator MHBst167.

    Science.gov (United States)

    Lun, Yong-Zhi; Cheng, Jun; Chi, Qing; Wang, Xue-Lei; Gao, Meng; Sun, Li-DA

    2014-08-01

    C-terminally truncated hepatitis B virus (HBV) middle size surface proteins (MHBst) has been shown to be a transcriptional activator and may be relevant to hepatocarcinogenesis by transactivating gene expression. In the present study, a pcDNA3.1(-)-MHBst167 vector coding for MHBst truncated at amino acid 167 (MHBst167) was constructed and transfected into the HepG2 hepatoma cell line. mRNA and protein expression of MHBst167 in the cells was detected by reverse transcription-polymerase chain reaction (RT-PCR) and western blot analysis. A cDNA library of genes transactivated by the truncated protein in HepG2 cells was made in pGEM-T Easy using suppression subtractive hybridization. The cDNAs were sequenced and analyzed with BLAST searching against the sequences in GenBank. The results showed that certain sequences, such as that of human proto-oncogene c-Myc, may be involved in tumor development. An expression vector pCAT3/c-Myc containing the chloramphenicol acetyltransferase (CAT) gene under the control of a c-Myc promoter was generated, and the transcriptional transactivating effect of MHBst167 on the c-Myc promoter was investigated by RT-PCR and western blotting. MHBst167 was found to upregulate the transcriptional activity of the promoter, as well as transcription and translation of c-Myc. MHBst167 was also shown to transactivate SV40 immediate early promoter, and transcriptionally transactivate the expression of human c-Myc. These findings provide new directions for studying the biological functions of MHBst167, and for a better understanding of the tumor development mechanisms of HBV infection.

  18. Balance of Yin and Yang: Ubiquitylation-Mediated Regulation of p53 and c-Myc

    Directory of Open Access Journals (Sweden)

    Mu-Shui Dai

    2006-08-01

    Full Text Available Protein ubiquitylation has been demonstrated to play a vital role not only in mediating protein turnover but also in modulating protein activity. The stability and activity of the tumor suppressor p53 and of the oncoprotein c-Myc are no exception. Both are regulated through independent ubiquitylation by several E3 ubiquitin ligases. Interestingly, p53 and c-Myc are functionally connected by some of these E3 enzymes and their regulator ARF, although these proteins play opposite roles in controlling cell growth and proliferation. The balance of this complex ubiquitylation network and its disruption during oncogenesis will be the topics of this review.

  19. What real influence does the proto-oncogene c-myc have in OSCC behavior?

    Science.gov (United States)

    Pérez-Sayáns, Mario; Suárez-Peñaranda, José Manuel; Pilar, Gayoso-Diz; Barros-Angueira, Francisco; Gándara-Rey, José Manuel; García-García, Abel

    2011-08-01

    The influence of c-myc in the carcinogenic process has been previously described although in the specific case of oral tumors it has been poorly tested. Myc proteins are a family of proto-oncogenes involved in the cell proliferation regulation, differentiation and apoptosis. The goal of this paper is to describe the functions of c-myc and its role as oncogene, assessing its expression by immunohistochemistry and genetic amplification studies, and studying its relationship with tumoral clinical and pathological variables, and describing genetic and molecular interactions in OSCC. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. Overexpression of the c-myc oncogene inhibits nonsense-mediated RNA decay in B lymphocytes.

    Science.gov (United States)

    Wang, Ding; Wengrod, Jordan; Gardner, Lawrence B

    2011-11-18

    The Myc transcription factor plays a vital role in both normal cellular physiology and in many human cancers. We have recently demonstrated that nonsense-mediated RNA decay (NMD), a mechanism that rapidly degrades select mRNAs, is inhibited by the stress-induced phosphorylation of translation initiation factor eIF2α, and this inhibition stabilizes many transcripts necessary for tumorigenesis. Here, we demonstrate that NMD is inhibited by high Myc expression. We show that the phosphorylation of eIF2α, likely due to the ability of Myc to generate reactive oxygen species and augment endoplasmic reticulum stress, is necessary for the inhibition of NMD by Myc. The inhibition of NMD both stabilizes and up-regulates multiple Myc targets, suggesting that the inhibition of NMD may play an important role in the dynamic regulation of genes by Myc.

  1. Lymphocytes DNA Content, P53, C-Myc And Bcl-2 As Predictive ...

    African Journals Online (AJOL)

    Cell cycle parameters as well as apoptotic and tumor markers directly control cell growth. DNA ploidy and S phase fraction, apoptosis fraction in addition to apoptotic inducer (p53, c-myc) and antiapoptotic marker (Bcl-2) were investigated in childhood with acute lymphoblastic leukemia (ALL) leukemia as a predictive ...

  2. Recessive genetic deregulation abrogates c-myc suppression by interferon and is implicated in oncogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Kimchi, A.; Resnitzky, D.; Ber, R.; Gat, G.

    1988-07-01

    Previously the authors demonstrated that many hematopoietic tumor cells are resistant to the inhibitory effects that interferon exerts on c-myc mRNA expression without losing other receptor-mediated intracellular responses. They report here that this partial resistance was overridden in two independent stable somatic cell hybrids prepared by fusion between sensitive and resistant cells. The c-myc mRNA transcribed from the active allele of the resistant parent cell was reduced by interferon within the context of the cell hybrid. It was therefore concluded that changes in the cis-acting sequences of c-myc were not involved in this type of relaxed regulation and that resistance resulted rather from inactivation or loss of postreceptor elements which operate in trans. The growth-stimulating effect that this genetic deregulation might have on cells was tested in experimental systems of cell differentiation in which an autocrine interferon is produced. For that purpose the authors isolated variant clones of M1 myeloid cells which were partially resistant to alpha and beta interferons and tested their growth behaviour during in vitro-induced differentiation. The resistant clones displayed higher proliferative activity on days 2 and 3 of differentiation than did the sensitive clones, which stopped proliferating. The loss of c-myc responses to the self-produced interferon disrupted the normal cessation of growth during differentiation and therefore might lead cells along the pathway of neoplasia.

  3. c-myc down-regulates class I HLA expression in human melanomas

    NARCIS (Netherlands)

    Versteeg, R.; NOORDERMEER, I. A.; Krüse-Wolters, M.; Ruiter, D. J.; Schrier, P. I.

    1988-01-01

    Expression of class I HLA antigen has been shown to be reduced in a number of human tumours. Here we show that in a panel of 11 melanoma cell lines with variable class I HLA expression an inverse correlation exists between the mRNA levels of c-myc and class I HLA. This suggests that high expression

  4. [Progress of research on Proto-oncogene c-myc, c-myb in platelet diseases].

    Science.gov (United States)

    Zhang, Ying; Chen, Rui; Zhao, Li

    2011-02-01

    The Proto-oncogene c-myc and c-myb has been shown to be crucial in the development of the hematopoietic system. The changes in the expression of c-myc are concerned the cell proliferation and differentiation, the expression products of which play an important regulatory role in cell growth, differentiation or malignant transformation. The c-myb involves in transcription and affects cell proliferation, differentiation, apoptosis. More recently, the researches on proto-oncogene c-myc, c-myb in hematopoietic regulation have gradually increased along with development of molecular biology, molecular immunology and cell biology. Scientists point out that the directive differentiation of erythroid and megakaryocytic progenitors, and platelet abnormalities all relate to the level of their expressions. The most common thrombocytopathy includes thrombocytopenia, thrombocytosis and so on. The etiology and the mechanism of these diseases are unknown. This article reviews the structure, function and the expression of c-myc and c-myb in platelet diseases and their significance.

  5. [Role of microRNA-223 and its target gene oncogene c-myc in hepatocellular carcinoma pathogenesis].

    Science.gov (United States)

    Zhao, Wen-Yue; Wang, Dong-Dong; Song, Meng-Qi; Yang, Ling; Ye, Jin; Chen, Li-Bo

    2011-02-01

    To investigate the regulatory role of microRNA-223 (miR-223) on c-myc and its role in hepatocarcinogenesis. miR-223 and c-myc mRNA expressions in normal tissue, paraneoplastic tissue, liver cancer tissue and liver cancer cells were tested with microRNA microarray and quantitative real-time PCR (qRT-PCR). C-myc protein expression was detected by Western blot. MiR-223 mimic was transfected into HepG2 cells and the expression changes of c-myc mRNA and protein were tested with qRT-PCR and Western blot respectively. MiR-223 was down-regulated by 61.53% and 30.77% respectively in hepatocellular carcinoma and adjacent tissues as compared to normal liver tissues and the expression of miR-223 was also decreased in HepG2 cell as compared to fetal liver cells L02, whereas the expressions of c-myc mRNA and protein increased in paraneoplastic and HCC tissues compared with normal liver tissues. It prompts that the expressions of miR-223 and c-myc are negatively correlated. No obvious difference found among c-myc mRNA expressions after miR-223 mimics transfection. The c-myc abnormal high-expression may play a dynamic role in hepatocarcinogenesis due to the miR-223 down-regulation.

  6. SIRT1 activation by a c-MYC oncogenic network promotes the maintenance and drug resistance of human FLT3-ITD acute myeloid leukemia stem cells.

    Science.gov (United States)

    Li, Ling; Osdal, Tereza; Ho, Yinwei; Chun, Sookhee; McDonald, Tinisha; Agarwal, Puneet; Lin, Allen; Chu, Su; Qi, Jing; Li, Liang; Hsieh, Yao-Te; Dos Santos, Cedric; Yuan, Hongfeng; Ha, Trung-Quang; Popa, Mihaela; Hovland, Randi; Bruserud, Øystein; Gjertsen, Bjørn Tore; Kuo, Ya-Huei; Chen, Wenyong; Lain, Sonia; McCormack, Emmet; Bhatia, Ravi

    2014-10-02

    The FLT3-ITD mutation is frequently observed in acute myeloid leukemia (AML) and is associated with poor prognosis. In such patients, FLT3 tyrosine kinase inhibitors (TKIs) are only partially effective and do not eliminate the leukemia stem cells (LSCs) that are assumed to be the source of treatment failure. Here, we show that the NAD-dependent SIRT1 deacetylase is selectively overexpressed in primary human FLT3-ITD AML LSCs. This SIRT1 overexpression is related to enhanced expression of the USP22 deubiquitinase induced by c-MYC, leading to reduced SIRT1 ubiquitination and enhanced stability. Inhibition of SIRT1 expression or activity reduced the growth of FLT3-ITD AML LSCs and significantly enhanced TKI-mediated killing of the cells. Therefore, these results identify a c-MYC-related network that enhances SIRT1 protein expression in human FLT3-ITD AML LSCs and contributes to their maintenance. Inhibition of this oncogenic network could be an attractive approach for targeting FLT3-ITD AML LSCs to improve treatment outcomes. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. The enhancement of c-myc expression in cultured epithelial cells by some cytotoxic metals.

    Science.gov (United States)

    Skilleter, D N; Price, R J; McNerney, R

    1991-01-01

    The toxic or carcinogenic metal ions Cd(2+), Hg(2+), Co(2+), Ni(2+) and Be(2+) are known to be potent inhibitors of cell division in cultured cells. The effects of these metal ions on the biphasic expression of the cell proliferation-associated proto-oncogene c-myc, have now been examined in epithelial cells (BL9L) derived from rat liver, using mRNA hybridization analysis following serum stimulation of synchronized (G(0)/G(1) cell cycle phase) confluent (quiescent) and non-confluent (proliferating) monolayer cultures. Exposure of the cells under these conditions to antiproliferative concentrations of BeSO(4) (50-100 mum), NiCl(2) (50 mum), CoCl(2) (50 mum), HgCl(2) (20-50 mum) or CdCl(2) (5-10 mum) showed that whereas Be(2+), Cd(2+) and Hg(2+) further increased steady-state c-myc mRNA levels throughout the treatment period, particularly in non-confluent cultures (two- to eight-fold enhancement), Co(2+) and Ni(2+) did not have a significant effect. In contrast, mRNA transcripts for constantly expressed cytoskeletal actin were essentially unchanged by all the metal ion treatments of the cells. The extent of the enhanced c-myc expression maintained in the cells by Be(2+), Cd(2+) or Hg(2+) treatment could also be broadly correlated with the degree of cell detachment from the culture dishes, which was ultimately produced within 20-24 hr. RNA and protein synthesis inhibitor studies indicate that the cytotoxic metal ions either directly or indirectly modify the normal control mechanisms for c-myc expression. It is concluded that an enhanced c-myc expression is a feature of the cells' response to certain cytotoxic metal ions, the magnitude of which may also be a potential index of pending cell damage.

  8. [Inhibition of proliferation in MCF-7 breast cancer cells by plasmid-based siRNA targeting to oncogene c-myc].

    Science.gov (United States)

    Zhou, Chang-Hua; Peng, Xiao-Dong; Wu, Jing; Zhang, Ping; Zhao, Zong-Rong; Wei, Da-Peng; Zhang, Chong-Jie

    2008-05-01

    To investigate the effects of plasmid-based siRNA targeting to oncogene c-myc on c-myc/ c-Myc expressions and cells proliferation in MCF-7 breast cancer cells. siRNA eukaryotic expression plasmid p-Mat01-1 targeting to the sequence 589-609 of oncogene c-myc and its mismatch plasmid p-Mis09-1 were constructed, and transiently transfected MCF-7 cells using Lipo2000. Semi-quantitative RT-PCR and Western blot were used to analyze the expressions of c-myc/c-Myc in MCF-7 cells, and cells proliferation was detected by MTT assay. p-Mat01-1 inhibited the expressions of c-myc mRNA (24 h: P < 0.01) and c-Myc protein (5 d. P < 0.01) in MCF-7 cells as compared with pEGFP-C1 and p-Mis09-1 controls, and suppressed the proliferation of MCF-7 cells significantly (3 d: P < 0.05, 5, 7 d: P < 0. 01). Plasmid-based siRNA targeting to oncogene c-myc could inhibit the expressions of c-myc/c-Myc in MCF-7 breast cancer cells efficiently, suggesting that the downregulation of c-myc/c-Myc could suppress the proliferation of MCF-7 cells in vitro.

  9. Effects of Klf4 and c-Myc Knockdown on Pluripotency Maintenance in Porcine Induced Pluripotent Stem Cell.

    Science.gov (United States)

    Liao, Yu-Jing; Chen, Yi-Shiou; Lee, Ja-Xin; Chen, Lih-Ren; Yang, Jenn-Rong

    2018-01-01

    The importance of Oct4 and Sox2 in maintaining pluripotency and self-renewal is well-understood, but the functions of Klf4 and c-Myc has not been fully investigated. In the present study, we attempted to determine the roles of Klf4 and c-Myc on pluripotency maintenance of porcine induced pluripotent stem (piPS) cells. In this experimental study, we performed short hairpin RNA (shRNA) to knock down the Klf4 and c-Myc functions of piPS cells and examined pluripotency markers and teratoma formation to evaluate piPS cell pluripotency. The shRNA-Klf4 and shRNA-c-Myc vectors containing a reporter gene, TagFP635, were transfected into piPS cells by lentivirus infection. The piPS cells fully expressing infrared fluorescence were selected to confirm gene knockdown of Klf4 and c-Myc reverse transcription-polymerase chain reaction (RT-PCR). Next, for pluripotency evaluation, expression of pluripotency markers was detected by immunocytochemical staining, and capability of teratoma formation was investigated by piPS cell transplantation into nonobese diabetic-severe combined immunodeficiency (NOD-SCID) mice. Our findings indicated that Klf4 and c-Myc functions of piPS cells were knocked down by shRNA transfection, and knockdown of Klf4 and c-Myc functions impaired expression of pluripotency markers such as Oct4, AP, SSEA-3, SSEA-4, TRA-1-6, and TRA-1-81. Furthermore, piPS cells without Klf4 and c-Myc expression failed to form teratomas. The pluripotency of piPS cells are crucially dependent upon Klf4 and c-Myc expression. These findings, suggesting potential mechanisms of Klf4 and c-Myc contribution to piPS cell formation, have important implications for application, regulation, and tumorigenesis of piPS cells.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-12-10

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

  11. 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.

  12. Receptor for hyaluronic acid- mediated motility (RHAMM) regulates HT1080 fibrosarcoma cell proliferation via a β-catenin/c-myc signaling axis.

    Science.gov (United States)

    Kouvidi, Katerina; Berdiaki, Aikaterini; Tzardi, Maria; Karousou, Evgenia; Passi, Alberto; Nikitovic, Dragana; Tzanakakis, George N

    2016-04-01

    High levels of hyaluronan (HA) synthesis in various cancer tissues, including sarcomas, are correlated with tumorigenesis and malignant transformation. RHAMM (receptor for hyaluronic acid-mediated motility) is overexpressed during tumor development in different malignancies. β-Catenin is a crucial downstream mediator of the Wnt signaling cascade which facilitates carcinogenic events characterized by deregulated cell proliferation. Real-time PCR, in vitro cell proliferation assay, siRNA transfection, flow cytometry, immunoprecipitation, western blotting and immunofluorescence were utilized. The reduction of RHAMM expression was strongly correlated with an inhibition of HT1080 fibrosarcoma cell growth (p≤0.01). LMWHA, in a RHAMM-dependent manner increases cell growth of HT1080 cells (p≤0.01). Both basal and LMWHA dependent growth of HT1080 cells was attenuated by β-catenin deficiency (p≤0.01). β-Catenin cytoplasmatic deposition is positively regulated by RHAMM (p≤0.01). Immunoflourescence and immunoprecipitation suggest that RHAMM/β-catenin form an intracellular complex. Transfection experiments identified c-myc as candidate downstream mediator of RHAMM/β-catenin effects on HT1080 fibrosarcoma cell proliferation. LMWHA/RHAMM downstream signaling regulates fibrosarcoma cell growth in a β-catenin/c-myc dependent manner. The present study suggests that RHAMM is a novel β-catenin intracellular binding partner, protecting β-catenin from degradation and supporting the nuclear translocation of this key cellular mediator, which results in c-myc activation and enhanced fibrosarcoma cell growth. Copyright © 2016 Elsevier B.V. All rights reserved.

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

    OpenAIRE

    C.R.O. Lima; Faleiro,M.B.R.; Rabelo,R.E.; V.A.S. Vulcani; Rubini,M.R.; Torres,F.A.G.; Moura,V.M.B.D.

    2016-01-01

    ABSTRACT The canine transmissible venereal tumor (TVT) affects the external genitalia of dogs by the natural transplant of viable tumor cells. Thus, this research aimed to diagnose and characterize TVT morphological patterns, identify the insertion of the LINE-1 element in C-MYC gene, by means of the polymerase chain reaction (PCR), and evaluate the immunohistochemical expression of C-MYC, p53, p21 and p27 proteins. The relationship between C-MYC and p53 proteins and their interference on the...

  14. The parafibromin tumor suppressor protein inhibits cell proliferation by repression of the c-myc proto-oncogene.

    Science.gov (United States)

    Lin, Ling; Zhang, Jian-Hua; Panicker, Leelamma M; Simonds, William F

    2008-11-11

    Parafibromin is a tumor suppressor protein encoded by HRPT2, a gene recently implicated in the hereditary hyperparathyroidism-jaw tumor syndrome, parathyroid cancer, and a subset of kindreds with familial isolated hyperparathyroidism. Human parafibromin binds to RNA polymerase II as part of a PAF1 transcriptional regulatory complex. The physiologic targets of parafibromin and the mechanism by which its loss of function can lead to neoplastic transformation are poorly understood. We show here that RNA interference with the expression of parafibromin or Paf1 stimulates cell proliferation and increases levels of the c-myc proto-oncogene product, a DNA-binding protein and established regulator of cell growth. This effect results from both c-myc protein stabilization and activation of the c-myc promoter, without alleviation of the c-myc transcriptional pause. Chromatin immunoprecipitation demonstrates the occupancy of the c-myc promoter by parafibromin and other PAF1 complex subunits in native cells. Knockdown of c-myc blocks the proliferative effect of RNA interference with parafibromin or Paf1 expression. These experiments provide a previously uncharacterized mechanism for the anti-proliferative action of the parafibromin tumor suppressor protein resulting from PAF1 complex-mediated inhibition of the c-myc proto-oncogene.

  15. Antiproliferative protein Tob directly regulates c-myc proto-oncogene expression through cytoplasmic polyadenylation element-binding protein CPEB.

    Science.gov (United States)

    Ogami, K; Hosoda, N; Funakoshi, Y; Hoshino, S

    2014-01-02

    The regulation of mRNA deadenylation constitutes a pivotal mechanism of the post-transcriptional control of gene expression. Here we show that the antiproliferative protein Tob, a component of the Caf1-Ccr4 deadenylase complex, is involved in regulating the expression of the proto-oncogene c-myc. The c-myc mRNA contains cis elements (CPEs) in its 3'-untranslated region (3'-UTR), which are recognized by the cytoplasmic polyadenylation element-binding protein (CPEB). CPEB recruits Caf1 deadenylase through interaction with Tob to form a ternary complex, CPEB-Tob-Caf1, and negatively regulates the expression of c-myc by accelerating the deadenylation and decay of its mRNA. In quiescent cells, c-myc mRNA is destabilized by the trans-acting complex (CPEB-Tob-Caf1), while in cells stimulated by the serum, both Tob and Caf1 are released from CPEB, and c-Myc expression is induced early after stimulation by the stabilization of its mRNA as an 'immediate-early gene'. Collectively, these results indicate that Tob is a key factor in the regulation of c-myc gene expression, which is essential for cell growth. Thus, Tob appears to function in the control of cell growth at least, in part, by regulating the expression of c-myc.

  16. Repression of c-Myc responsive genes in cycling cells causes G1 arrest through reduction of cyclin E/CDK2 kinase activity

    NARCIS (Netherlands)

    Berns, K.; Hijmans, E.M.; Bernards, R.A.

    1997-01-01

    The c-myc gene encodes a sequence-specific DNA binding protein involved in proliferation and oncogenesis. Activation of c-myc expression in quiescent cells is sufficient to mediate cell cycle entry, whereas inhibition of c-myc expression causes cycling cells to withdraw from the cell cycle. To

  17. Linc-RoR promotes c-Myc expression through hnRNP I and AUF1.

    Science.gov (United States)

    Huang, Jianguo; Zhang, Ali; Ho, Tsui-Ting; Zhang, Ziqiang; Zhou, Nanjiang; Ding, Xianfeng; Zhang, Xu; Xu, Min; Mo, Yin-Yuan

    2016-04-20

    Linc-RoR was originally identified to be a regulator for induced pluripotent stem cells in humans and it has also been implicated in tumorigenesis. However, the underlying mechanism of Linc-RoR-mediated gene expression in cancer is poorly understood. The present study demonstrates that Linc-RoR plays an oncogenic role in part through regulation of c-Myc expression. Linc-RoR knockout (KO) suppresses cell proliferation and tumor growth. In particular, Linc-RoR KO causes a significant decrease in c-Myc whereas re-expression of Linc-RoR in the KO cells restores the level of c-Myc. Mechanistically, Linc-RoR interacts with heterogeneous nuclear ribonucleoprotein (hnRNP) I and AU-rich element RNA-binding protein 1 (AUF1), respectively, with an opposite consequence to their interaction with c-Myc mRNA. While Linc-RoR is required for hnRNP I to bind to c-Myc mRNA, interaction of Linc-RoR with AUF1 inhibits AUF1 to bind to c-Myc mRNA. As a result, Linc-RoR may contribute to the increased stability of c-Myc mRNA. Although hnRNP I and AUF1 can interact with many RNA species and regulate their functions, with involvement of Linc-RoR they would be able to selectively regulate mRNA stability of specific genes such as c-Myc. Together, these results support a role for Linc-RoR in c-Myc expression in part by specifically enhancing its mRNA stability, leading to cell proliferation and tumorigenesis. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  18. Induced pluripotent stem cells without c-Myc reduce airway responsiveness and allergic reaction in sensitized mice.

    Science.gov (United States)

    Wang, Chien-Ying; Chiou, Guang-Yuh; Chien, Yueh; Wu, Chia-Chao; Wu, Tzee-Chung; Lo, Wen-Tsung; Chen, Shyi-Jou; Chiou, Shih-Hwa; Peng, Ho-Jen; Huang, Ching-Feng

    2013-12-15

    Allergic disorders have increased substantially in recent years. Asthma is characterized by airway damage and remodeling. Reprogramming induced pluripotent stem cells (iPSCs) from adult somatic cells transfected by Oct-4/Sox-2/Klf-4, but not c-Myc, has shown the potential of embryonic-like cells. These cells have potential for multilineage differentiation and provide a resource for stem cell-based utility. However, the therapeutic potential of iPSCs without c-Myc (iPSC-w/o-c-Myc) in allergic diseases and airway hyperresponsiveness has not been investigated. The aim of this study was to evaluate the therapeutic effect of iPSC-w/o-c-Myc transplantation in a murine asthma model. BALB/c mice were sensitized with alum-adsorbed ovalbumin (OVA) and then challenged with aerosolized OVA. Phosphate-buffered saline or iPSC-w/o-c-Myc was then intravenously injected after inhalation. Serum allergen-specific antibody levels, airway hyperresponsiveness, cytokine levels in spleen cells and bronchoalveolar lavage fluid (BALF), and cellular distribution in BALF were then examined. Treatment with iPSC-w/o-c-Myc effectively suppressed both Th1 and Th2 antibody responses, which was characterized by reduction in serum allergen-specific IgE, IgG, IgG1, and IgG2a levels as well as in interleukin-5 and interferon-γ levels in BALF and in OVA-incubated splenocytes. Meanwhile, regulatory cytokine, interleukin-10, was enhanced. Transplantation of iPSC-w/o-c-Myc also significantly attenuated cellular infiltration in BALF and allergic airway hyperresponsiveness. However, no tumor formation was observed 6 months after transplantation. Administration of iPSC-w/o-c-Myc not only inhibited Th1 inflammatory responses but also had therapeutic effects on systemic allergic responses and airway hyperresponsiveness. iPSC-w/o-c-Myc transplantation may be a potential modality for treating allergic reactions and bronchial asthma.

  19. 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.

  20. Bioinformatic analysis of c-Myc target from laryngeal cancer cell gene of laryngeal cancer.

    Science.gov (United States)

    Zhang, Wei-Dong; Chen, He-Xin; Wang, Yun-Xia; Chen, Zhi-Ping; Shan, Zhong-Jie; Xu, Guang

    2016-01-01

    The aim was to explore the structure and functions of new target spot c-Myc target from laryngeal cancer cell. (MTLC) of c-Myc gene. This study adopted bioinformatic methods to analyze the physicochemical property, secondary structure, hydrophobic region, a transmembrane region, and prediction of functions. The results showed that the whole length of the open reading frames was 708 bp, coding was 235 amino acids. This protein was a basic protein possessed two transmembrane structures and weight was about 26592.5 Da. The main elements of secondary structure were alpha-helix and random coil. MTLC was a membrane constitutive protein that possessed signal transduction and regulation may locate on karyotheca as results of subcellular localization and function prediction. This study has provided the theoretical basis for the further discussion of the effect and mechanism of action of MTLC in the occurrence of laryngeal cancer.

  1. Regulation of c-Myc mRNA by L11 in Response to UV and Gamma Irradiation

    Science.gov (United States)

    2014-12-01

    L11 mutations are associated with cleft palate and abnormal thumbs in Diamond-Blackfan anemia patients. Am. J. Hum. Genet. 83:769–780. 23. Gomez-Roman...24 (Figure 1). We also tested an array of miRNAs possessing tumor suppressor functions for L11 binding miR-16 miR-1248 miR-3944 (-) miR-191 miR...32), and tristetraprolin (TTP) (39), have been found to bind to c-myc AREs and regulate c-myc mRNA sta- bility. To test whether L11 binds to c-myc

  2. 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.

  3. The Histone Acetyltransferase GCN5 Expression Is Elevated and Regulated by c-Myc and E2F1 Transcription Factors in Human Colon Cancer

    Science.gov (United States)

    Yin, Yan-Wei; Jin, Hong-Jian; Zhao, Wenjing; Gao, Beixue; Fang, Jiangao; Wei, Junmin; Zhang, Donna D.; Zhang, Jianing; Fang, Deyu

    2017-01-01

    The histone acetyltransferase GCN5 has been suggested to be involved in promoting cancer cell growth. But its role in human colon cancer development remains unknown. Herein we discovered that GCN5 expression is significantly upregulated in human colon adenocarcinoma tissues. We further demonstrate that GCN5 is upregulated in human colon cancer at the mRNA level. Surprisingly, two transcription factors, the oncogenic c-Myc and the proapoptotic E2F1, are responsible for GCN5 mRNA transcription. Knockdown of c-Myc inhibited colon cancer cell proliferation largely through downregulating GCN5 transcription, which can be fully rescued by the ectopic GCN5 expression. In contrast, E2F1 expression induced human colon cancer cell death, and suppression of GCN5 expression in cells with E2F1 overexpression further facilitated cell apoptosis, suggesting that GCN5 expression is induced by E2F1 as a possible negative feedback in suppressing E2F1-mediated cell apoptosis. In addition, suppression of GCN5 with its specific inhibitor CPTH2 inhibited human colon cancer cell growth. Our studies reveal that GCN5 plays a positive role in human colon cancer development, and its suppression holds a great therapeutic potential in antitumor therapy. PMID:26637399

  4. c-Myc activates multiple metabolic networks to generate substrates for cell-cycle entry.

    Science.gov (United States)

    Morrish, F; Isern, N; Sadilek, M; Jeffrey, M; Hockenbery, D M

    2009-07-09

    Cell proliferation requires the coordinated activity of cytosolic and mitochondrial metabolic pathways to provide ATP and building blocks for DNA, RNA and protein synthesis. Many metabolic pathway genes are targets of the c-myc oncogene and cell-cycle regulator. However, the contribution of c-Myc to the activation of cytosolic and mitochondrial metabolic networks during cell-cycle entry is unknown. Here, we report the metabolic fates of [U-(13)C] glucose in serum-stimulated myc(-/-) and myc(+/+) fibroblasts by (13)C isotopomer NMR analysis. We demonstrate that endogenous c-myc increased (13)C labeling of ribose sugars, purines and amino acids, indicating partitioning of glucose carbons into C1/folate and pentose phosphate pathways, and increased tricarboxylic acid cycle turnover at the expense of anaplerotic flux. Myc expression also increased global O-linked N-acetylglucosamine protein modification, and inhibition of hexosamine biosynthesis selectively reduced growth of Myc-expressing cells, suggesting its importance in Myc-induced proliferation. These data reveal a central organizing function for the Myc oncogene in the metabolism of cycling cells. The pervasive deregulation of this oncogene in human cancers may be explained by its function in directing metabolic networks required for cell proliferation.

  5. Quantitative characterization of the interactions among c-myc transcriptional regulators FUSE, FBP, and FIR.

    Science.gov (United States)

    Hsiao, Hsin-Hao; Nath, Abhinav; Lin, Chi-Yen; Folta-Stogniew, Ewa J; Rhoades, Elizabeth; Braddock, Demetrios T

    2010-06-08

    Human c-myc is critical for cell homeostasis and growth but is a potent oncogenic factor if improperly regulated. The c-myc far-upstream element (FUSE) melts into single-stranded DNA upon active transcription, and the noncoding strand FUSE recruits an activator [the FUSE-binding protein (FBP)] and a repressor [the FBP-interacting repressor (FIR)] to fine-tune c-myc transcription in a real-time manner. Despite detailed biological experiments describing this unique mode of transcriptional regulation, quantitative measurements of the physical constants regulating the protein-DNA interactions remain lacking. Here, we first demonstrate that the two FUSE strands adopt different conformations upon melting, with the noncoding strand DNA in an extended, linear form. FBP binds to the linear noncoding FUSE with a dissociation constant in the nanomolar range. FIR binds to FUSE more weakly, having its modest dissociation constants in the low micromolar range. FIR is monomeric under near-physiological conditions but upon binding of FUSE dimerizes into a 2:1 FIR(2)-FUSE complex mediated by the RRMs. In the tripartite interaction, our analysis suggests a stepwise addition of FIR onto an activating FBP-FUSE complex to form a quaternary FIR(2)-FBP-FUSE inhibitory complex. Our quantitative characterization enhances understanding of DNA strand preference and the mechanism of the stepwise complex formation in the FUSE-FBP-FIR regulatory system.

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

    Science.gov (United States)

    Moosvi, Zama; Rekha, K

    2013-01-01

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

  7. Redox regulation of cardiomyocyte cell cycling via an ERK1/2 and c-Myc-dependent activation of cyclin D2 transcription

    Science.gov (United States)

    Murray, Thomas V.A.; Smyrnias, Ioannis; Schnelle, Moritz; Mistry, Rajesh K.; Zhang, Min; Beretta, Matteo; Martin, Daniel; Anilkumar, Narayana; de Silva, Shana M.; Shah, Ajay M.; Brewer, Alison C.

    2015-01-01

    Adult mammalian cardiomyocytes have a very limited capacity to proliferate, and consequently the loss of cells after cardiac stress promotes heart failure. Recent evidence suggests that administration of hydrogen peroxide (H2O2), can regulate redox-dependent signalling pathway(s) to promote cardiomyocyte proliferation in vitro, but the potential relevance of such a pathway in vivo has not been tested. We have generated a transgenic (Tg) mouse model in which the H2O2-generating enzyme, NADPH oxidase 4 (Nox4), is overexpressed within the postnatal cardiomyocytes, and observed that the hearts of 1–3 week old Tg mice pups are larger in comparison to wild type (Wt) littermate controls. We demonstrate that the cardiomyocytes of Tg mouse pups have increased cell cycling capacity in vivo as determined by incorporation of 5-bromo-2′-deoxyuridine. Further, microarray analyses of the transcriptome of these Tg mouse hearts suggested that the expression of cyclin D2 is significantly increased. We investigated the molecular mechanisms which underlie this more proliferative phenotype in isolated neonatal rat cardiomyocytes (NRCs) in vitro, and demonstrate that Nox4 overexpression mediates an H2O2-dependent activation of the ERK1/2 signalling pathway, which in turn phosphorylates and activates the transcription factor c-myc. This results in a significant increase in cyclin D2 expression, which we show to be mediated, at least in part, by cis-acting c-myc binding sites within the proximal cyclin D2 promoter. Overexpression of Nox4 in NRCs results in an increase in their proliferative capacity that is ablated by the silencing of cyclin D2. We further demonstrate activation of the ERK1/2 signalling pathway, increased phosphorylation of c-myc and significantly increased expression of cyclin D2 protein in the Nox4 Tg hearts. We suggest that this pathway acts to maintain the proliferative capacity of cardiomyocytes in Nox4 Tg pups in vivo and so delays their exit from the cell

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

    NARCIS (Netherlands)

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

    1990-01-01

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

  9. 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

  10. The distribution of the c-myc oncogene product in malignant lymphomas and various normal tissues as demonstrated by immunocytochemistry.

    Science.gov (United States)

    Jack, A. S.; Kerr, I. B.; Evan, G.; Lee, F. D.

    1986-01-01

    The expression of c-myc was studied in 51 malignant lymphomas and in a variety of normal tissues by immunocytochemistry using monoclonal antibodies raised to different synthetic peptides and reacting monospecifically with the c-myc product (p62c-myc). The c-myc product was detected in only a minority of malignant lymphomas principally those containing cells with immunoblastic characteristics, and was predominantly localised to the cytoplasm. In normal lymphoid tissues only plasma cells and histiocytes were found to have immunoreactivity. In non-lymphoid normal tissues, however, the c-myc product was distributed widely. Marked differences in its intracellular distribution were apparent in different tissues. These findings suggest that the relationship of p62c-myc expression to cell division may be more complex than previously suggested by in vitro studies, and raise the possibility that it may have other functions within the cell. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 PMID:3521694

  11. Analysis of polyadenylation site usage of the c-myc oncogene.

    OpenAIRE

    Laird-Offringa, I A; Elfferich, P; Knaken, H J; Ruiter, J.; van der Eb, A J

    1989-01-01

    The c-myc gene contains 2 well conserved polyadenylation (pA) sites. In all human and rat cell lines from various differentiation stages and tissue types the amount of mRNA terminating at the second pA site is 6-fold higher than the amount ending at the upstream site. This is not due to a difference in stability of the two mRNA types and therefore must be due to preferential usage of the downstream site. The usage of the pA sites is not altered during growth factor induction of quiescent cell...

  12. Localisation of lung cancer by a radiolabelled monoclonal antibody against the c-myc oncogene product

    Energy Technology Data Exchange (ETDEWEB)

    Chan, S.Y.T.; Evan, G.I.; Ritson, A.; Watson, J.; Wraight, P.; Sikora, K.

    1986-11-01

    A set of mouse monoclonal antibodies against the c-myc oncogene product, a 62,000 dalton nuclear binding protein involved in cell cycle control, has been constructed by immunisation with synthetic peptide fragments. One such antibody, CT14, was radiolabelled with /sup 131/I and administered to 20 patients with different malignant diseases. Good tumour localisation was observed in 12 out of 14 patients with primary bronchial carcinoma but not in patients with pulmonary metastases from primary tumours elsewhere. Successfully localised tumours were all 3 cm or more in diameter. Monoclonal antibodies against oncogene products may provide novel selective tools for the diagnosis and therapy of cancer.

  13. The role of the proto-oncogene c-myc in B lymphocyte differentiation.

    Science.gov (United States)

    Fernandez, David; Sanchez-Arevalo, Victor Javier; de Alboran, Ignacio Moreno

    2012-01-01

    Since the discovery of the myc gene, few genes are likely to have such influence on biomedical research. The diversity of the biological functions regulated by this transcription factor and its impact in human health have attracted investigators from many different fields. The development of conditional knockout mouse models has allowed for the characterization of Myc-driven molecular mechanisms in primary cells in physiological and pathological conditions. In this review, we discuss some of the main functions and recent findings regarding c-Myc in in vivo B lymphocyte differentiation from early progenitors to terminally differentiated cells.

  14. TCEAL7 Inhibition of c-Myc Activity in Alternative Lengthening of Telomeres Regulates hTERT Expression

    Directory of Open Access Journals (Sweden)

    Kyle Lafferty-Whyte

    2010-05-01

    Full Text Available Replicative senescence forms a major barrier to tumor progression. Cancer cells bypass this by using one of the two known telomere maintenance mechanisms: telomerase or the recombination-based alternative lengthening of telomeres (ALT mechanism. The molecular details of ALT are currently poorly understood. We have previously shown that telomerase is actively repressed through complex networks of kinase, gene expression, and chromatin regulation. In this study, we aimed to gain further understanding of the role of kinases in the regulation of telomerase expression in ALT cells. Using a whole human kinome small interfering RNA (siRNA screen, we highlighted 106 kinases whose expression is linked to human telomerase reverse transcriptase (hTERT promoter activity. Network modeling of transcriptional regulation implicated c-Myc as a key regulator of the 106 kinase hits. Given our previous observations of lower c-Myc activity in ALT cells, we further explored its potential to regulate telomerase expression in ALT. We found increased c-Myc binding at the hTERT promoter in telomerase-positive compared with ALT cells, although no expression differences in c-Myc, Mad, or Max were observed between ALT and telomerase-positive cells that could explain decreased c-Myc activity in ALT. Instead, we found increased expression of the c-Myc competitive inhibitor TCEAL7 in ALT cells and tumors and that alteration of TCEAL7 expression levels in ALT and telomerase-positive cells affects hTERT expression. Lower c-Myc activity in ALT may therefore be obtained through TCEAL7 regulation. Thus, TCEAL7 may present an interesting novel target for cancer therapy, which warrants further investigation.

  15. Alternative DNA structure formation in the mutagenic human c-MYC promoter.

    Science.gov (United States)

    Del Mundo, Imee Marie A; Zewail-Foote, Maha; Kerwin, Sean M; Vasquez, Karen M

    2017-05-05

    Mutation 'hotspot' regions in the genome are susceptible to genetic instability, implicating them in diseases. These hotspots are not random and often co-localize with DNA sequences potentially capable of adopting alternative DNA structures (non-B DNA, e.g. H-DNA and G4-DNA), which have been identified as endogenous sources of genomic instability. There are regions that contain overlapping sequences that may form more than one non-B DNA structure. The extent to which one structure impacts the formation/stability of another, within the sequence, is not fully understood. To address this issue, we investigated the folding preferences of oligonucleotides from a chromosomal breakpoint hotspot in the human c-MYC oncogene containing both potential G4-forming and H-DNA-forming elements. We characterized the structures formed in the presence of G4-DNA-stabilizing K+ ions or H-DNA-stabilizing Mg2+ ions using multiple techniques. We found that under conditions favorable for H-DNA formation, a stable intramolecular triplex DNA structure predominated; whereas, under K+-rich, G4-DNA-forming conditions, a plurality of unfolded and folded species were present. Thus, within a limited region containing sequences with the potential to adopt multiple structures, only one structure predominates under a given condition. The predominance of H-DNA implicates this structure in the instability associated with the human c-MYC oncogene. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  16. DSC Deconvolution of the Structural Complexity of c-MYC P1 Promoter G-Quadruplexes

    Science.gov (United States)

    Dettler, Jamie M.; Buscaglia, Robert; Le, Vu H.; Lewis, Edwin A.

    2011-01-01

    We completed a biophysical characterization of the c-MYC proto-oncogene P1 promoter quadruplex and its interaction with a cationic porphyrin, 5,10,15,20-tetra(N-methyl-4-pyridyl)porphyrin (TMPyP4), using differential scanning calorimetry, isothermal titration calorimetry, and circular dichroism spectroscopy. We examined three different 24-mer oligonucleotides, including the wild-type (WT) sequence found in the c-MYC P1 promoter and two mutant G→T sequences that are known to fold into single 1:2:1 and 1:6:1 loop isomer quadruplexes. Biophysical experiments were performed on all three oligonucleotide sequences at two different ionic strengths (30 mM [K+] and 130 mM [K+]). Differential scanning calorimetry experiments demonstrated that the WT quadruplex consists of a mixture of at least two different folded conformers at both ionic strengths, whereas both mutant sequences exhibit a single two-state melting transition at both ionic strengths. Isothermal titration calorimetry experiments demonstrated that both mutant sequences bind 4 mols of TMPyP4 to 1 mol of DNA, in similarity to the WT sequence. The circular dichroism spectroscopy signatures for all three oligonucleotides at both ionic strengths are consistent with an intramolecular parallel stranded G-quadruplex structure, and no change in quadruplex structure is observed upon addition of saturating amounts of TMPyP4 (i.e., 4:1 TMPyP4/DNA). PMID:21402034

  17. The oncogene c-Myc coordinates regulation of metabolic networks to enable rapid cell cycle entry.

    Science.gov (United States)

    Morrish, Fionnuala; Neretti, Nicola; Sedivy, John M; Hockenbery, David M

    2008-04-15

    The c-myc proto-oncogene is rapidly activated by serum and regulates genes involved in metabolism and cell cycle progression. This gene is thereby uniquely poised to coordinate both the metabolic and cell cycle regulatory events required for cell cycle entry. However, this function of Myc has not been evaluated. Using a rat fibroblast model of isogenic cell lines, myc(-/-), myc(+/-), myc(+/+) and myc(-/-) cells with an inducible c-myc transgene (mycER), we show that the Myc protein programs cells to utilize both oxidative phosphorylation and glycolysis to drive cell cycle progression. We demonstrate this coordinate regulation of metabolic networks is essential, as specific inhibitors of these pathways block Myc-induced proliferation. Metabolic events temporally correlated with cell cycle entry include increased oxygen consumption, mitochondrial function, pyruvate and lactate production, and ATP generation. Treatment of normal cells with inhibitors of oxidative phosphorylation recapitulates the myc(-/-) phenotype, resulting in impaired cell cycle entry and reduced metabolism. Combined with a kinetic expression profiling analysis of genes linked to mitochondrial function, our study indicates that Myc's ability to coordinately regulate the mitochondrial metabolic network transcriptome is required for rapid cell cycle entry. This function of Myc may underlie the pervasive presence of Myc in many human cancers.

  18. 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.

  19. Infection by Toxoplasma gondii Specifically Induces Host c-Myc and the Genes This Pivotal Transcription Factor Regulates

    Science.gov (United States)

    Franco, Magdalena; Shastri, Anjali J.

    2014-01-01

    Toxoplasma gondii infection has previously been described to cause dramatic changes in the host transcriptome by manipulating key regulators, including STATs, NF-κB, and microRNAs. Here, we report that Toxoplasma tachyzoites also mediate rapid and sustained induction of another pivotal regulator of host cell transcription, c-Myc. This induction is seen in cells infected with all three canonical types of Toxoplasma but not the closely related apicomplexan parasite Neospora caninum. Coinfection of cells with both Toxoplasma and Neospora still results in an increase in the level of host c-Myc, showing that c-Myc is actively upregulated by Toxoplasma infection (rather than repressed by Neospora). We further demonstrate that this upregulation may be mediated through c-Jun N-terminal protein kinase (JNK) and is unlikely to be a nonspecific host response, as heat-killed Toxoplasma parasites do not induce this increase and neither do nonviable parasites inside the host cell. Finally, we show that the induced c-Myc is active and that transcripts dependent on its function are upregulated, as predicted. Hence, c-Myc represents an additional way in which Toxoplasma tachyzoites have evolved to specifically alter host cell functions during intracellular growth. PMID:24532536

  20. The expression of p53, Rb, and c-myc protein in cervical cancer by immunohistochemistry stain

    Directory of Open Access Journals (Sweden)

    AMBAR MUDIGDO

    2005-07-01

    Full Text Available The pathogenesis of cancer as whole (50% is caused by gene mutation. Pathogenesis of cervical cancer has focusing on Human Papilloma Virus (HPV. Early-7 (E7 proteins of HPV shell bind the Rb tumor suppressor gene, so pRb (Rb protein can’t express. Because of the E2F transcription factor gene can’t bound with pRb, so E2F gene are going active and help c-myc for DNA replication and to stimuli the cell cycle. E6 protein of HPV is bind to and facilitates the degradation of the p53 tumor suppressor gene product. The objective of this experiment is to known the expression of p53, Rb and c-myc proteins in cancer of uterine cervix. Nineteen blocks paraffin tissue of cervical cancer are cut in thoroughly cleaned cryotome and place in glass plate that covered with poly-elysine. The immunohistochemistry is done with monoclonal antibody anti p53, Rb and c-myc proteins. The Result of this experiment is shown that the expression of proteins of p53 protein is 40%, Rb protein is 30.8% and c-myc protein is 50.1%. The conclusion from this experiment is that the expression of p53, Rb and c-myc proteins in cervical cancer are in mild category (30-70%. The experiment about cervical cancer is suggested.

  1. Mechanism of action of EBV, Bcl-2, p53, c-Myc and Rb in non-Hodgkin's lymphoma.

    Science.gov (United States)

    Song, W; Liu, M-G; Zhang, J-B; Zhang, J-J; Sun, M-M; Yu, Q-K

    2016-01-01

    The aim of the present study is to explore the mechanism of action of several proteins, including Epstein-Barr virus (EBV), B-cell lymphoma (Bcl)-2, p53, c-Myc and retinoblastoma (Rb), in Non-Hodgkin's lymphoma (NHL). Between July 2010 and July 2015, samples of 142 patients with pathologically confirmed NHL which presented at our institution were included in the observation group. In addition, samples from 55 patients with hyperplastic lymphadenitis presented during the same period were enrolled as control group. The expressions of EBV (+), p53(+), Bcl-2(+), Rb(-) and c-Myc(+) were determined and compared Between July 2010 and July 2015, samples of 142 patients with pathologically confirmed NHL which presented at our institution were included in the observation group. In addition, samples from 55 patients with hyperplastic lymphadenitis presented during the same period were enrolled as control group. The expressions of EBV (+), p53(+), Bcl-2(+), Rb(-) and c-Myc(+) were determined and compared among different subtypes and stages of NHLs of observation group. Besides, the correlation of EBV with p53, Bcl-2, Rb and c-Myc were investigated in NHLs of observation group. In the observation group, the expression rates of EBV(+), p53(+), Bcl-2(+), Rb(-), and c-Myc(+) were significantly higher than those, respectively, in the control group (p EBV expression and the expressions of p53, Bcl-2, Rb and c-Myc in the observation group (p > 0.05). The expression rates of p53(+) and Bcl-2(+) were significantly higher in aggressive and highly-aggressive NHLs than in indolent NHLs of the observation group (p EBV(+), p53(+), Bcl-2(+), Rb(-), and c-Myc(+) were significantly higher in stage III-IV NHLs than in stage I-II NHLs (p EBV(+), p53(+), Bcl-2(+), Rb(-), and c-Myc(+) are closely associated with NHL pathogenesis. Expressions of these proteins are higher in later stages of NHLs, and expressions of p53(+) and Bcl-2(+) are higher in more aggressive NHLs.

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

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    Trumpp Andreas

    2009-09-01

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

  3. Differential control of proto-oncogene c-myc and c-fos expression in lymphocytes and fibroblasts.

    Science.gov (United States)

    McNerney, R; Darling, D; Johnstone, A

    1987-01-01

    In lymphocytes stimulated with the mitogen phytohaemagglutinin, an inhibitor of the enzyme ADP-ribosyltransferase (ADPRT) completely blocks the proliferative response and the increase in expression of the proto-oncogene c-myc without affecting c-fos significantly. Conversely, in fibroblasts the serum-induced growth is not affected by the ADPRT inhibitor, and both oncogenes are dramatically super-induced. Hence there are differences between lymphocyte and fibroblast early responses to mitogenic stimulation and also between regulation of c-fos and c-myc gene expression. Images Fig. 2. Fig. 3. PMID:3117047

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

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    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.

  5. Localisation of lung cancer by a radiolabelled monoclonal antibody against the c-myc oncogene product.

    Science.gov (United States)

    Chan, S. Y.; Evan, G. I.; Ritson, A.; Watson, J.; Wraight, P.; Sikora, K.

    1986-01-01

    A set of mouse nonoclonal antibodies against the c-myc oncogene product, a 62,000 dalton nuclear binding protein involved in cell cycle control, has been constructed by immunisation with synthetic peptide fragments. One such antibody, CT14, was radiolabelled with 131I and administered to 20 patients with different malignant diseases. Good tumour localisation was observed in 12 out of 14 patients with primary bronchial carcinoma but not in patients with pulmonary metastases from primary tumours elsewhere. Successfully localised tumours were all 3 cm or more in diameter. Monoclonal antibodies against oncogene products may provide novel selective tools for the diagnosis and therapy of cancer. Images Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 PMID:3801273

  6. Transplantation of induced pluripotent stem cells without C-Myc attenuates retinal ischemia and reperfusion injury in rats.

    Science.gov (United States)

    Fang, I-Mo; Yang, Chung-May; Yang, Chang-Hao; Chiou, Shih-Hwa; Chen, Muh-Shy

    2013-08-01

    Induced pluripotent stem cells (iPSC) are novel stem cell populations, but the role of iPSC in retinal ischemia and reperfusion (I/R) injury remains unknown. Since oncogene c-Myc is substantially contributed to tumor formation, in this study, we investigated the effects, mechanisms and safety of subretinal transplantation of iPSC without c-Myc (non-c-Myc iPSC) in a rat model of retinal I/R injury. Retinal I/R injury was induced by raising the intraocular pressure of Sprague-Dawley rats to 110 mmHg for 60 min. A subretinal injection of non-c-Myc iPSC or murine epidermal fibroblast was given 2 h after I/R injury. Electroretinograms (ERG) were performed to determine the functionality of the retinas. The surviving retinal ganglion cells (RGCs) and retinal apoptosis following I/R injury were determined by counting NeuN-positive cells in whole-mounted retinas and TUNEL staining, respectively. The generation of reactive oxygen species (ROS) and the activities of superoxide dismutase (SOD) and catalase (CAT) in the retinal tissues were determined by lucigenin- and luminol-enhanced chemiluminescence and enzyme-linked immunosorbent assay (ELISA). The degree of retinal oxidative damage was assessed by nitrotyrosine, acrolein, and 8-hydroxy-2'-deoxyguanosine (8-OHdG) staining. The expression of brain-derived neurotrophic factor (BDNF), ciliary neurotrophic factor (CNTF) and basic fibroblast growth factor (bFGF) in retinas was measured by immunohistochemistry and ELISA. We found that subretinal transplantation of non-c-Myc iPSC significantly suppressed the I/R-induced reduction in the ERG a- and b-wave ratio, attenuated I/R-induced loss of RGCs and remarkably ameliorated retinal morphological changes. Non-c-Myc iPSC potentially increased the activities of SOD and CAT, decreased the levels of ROS, which may account for preventing retinal cells from apoptotic cell death. In addition, the levels of BDNF and CNTF in retina were significantly elevated in non-c-Myc iPSC-treated eyes

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

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    C.R.O. Lima

    2016-06-01

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

  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

  9. Expression of merlin, NDRG2, ERBB2, and c-MYC in meningiomas: relationship with tumor grade and recurrence.

    Science.gov (United States)

    Ongaratti, B R; Silva, C B O; Trott, G; Haag, T; Leães, C G S; Ferreira, N P; Oliveira, M C; Pereira-Lima, J F S

    2016-01-01

    Meningiomas are common, usually benign tumors of the central nervous system that have a high rate of post-surgical recurrence or regrowth. We determined expression of the proteins merlin, NDRG2, ERBB2, and c-MYC in meningiomas using immunohistochemistry and assessed relationships between protein expression and gender, age, tumor grade, and recurrence or regrowth. The study sample comprised 60 patients, (44 women and 16 men) with a mean age of 53.2 ± 12.7 years. Tumors were classified as grade I (n=48) or grades II and III (n=12). Expression of merlin, NDRG2, ERBB2, and c-MYC was not significantly different statistically with relation to gender, age, or meningioma recurrence or regrowth. Merlin was expressed in 100% of the cases. No statistically significant difference between tumor grade and recurrence or regrowth was identified. Statistically significant differences were identified between the mean age of patients with grade I (54.83 ± 11.60) and grades II and III (46.58 ± 15.08) meningiomas (P=0.043), between strong c-MYC expression and grades II and III (Pmerlin on tumorigenesis, the association of c-MYC with aggressive meningiomas, and that partial surgical resection is associated with tumor recurrence or regrowth.

  10. [Influence of RNA interference targeting against human telomerase reverse transcriptase on expression of C-myc protein].

    Science.gov (United States)

    Chi, Huaming; Tao, Zezhang; Chen, Shiming; Xiao, Bokui; Zhan, Hanzhang

    2005-11-01

    To investigate the effect of inhibiting human telomerase reverse transcriptase (hTERT) on expression of C-myc protein by RNA interference (RNAi) in the larynx cancer cell line, Hep-2. The primary structures of hTERT cDNA were found in GeneBank. Then the structure analyses were done according to the strategy of RNAi, which determined the specific base sequences to design shRNA plasmid. One type of plasmid, pshRNA1, involved in fluorescein gene was synthesized based on the specific base sequence. Control pshRNA2-a random sequence-were also constructed. METAFECTENE was used as the transfect ion reagent. Cells were treated daily with pshRNA1-2 or normal culture medium respectively. After administration of pshRNA1-2, hTERT mRNA was detected by RT-PCR, hTERT protein and C-myc protein were examined by Western Blot. The expression of hTERT mRNA and protein were both significantly decreased after treated by pshRNA1 (P < 0.05). The expression of C-myc protein was significantly increased after treated by pshRNA1 (P < 0.01). The inhibition of hTERT expression could increase the expression of C-myc protein in Hep-2 cells.

  11. Amino-terminal domains of c-myc and N-myc proteins mediate binding to the retinoblastoma gene product

    Science.gov (United States)

    Rustgi, Anil K.; Dyson, Nicholas; Bernards, Rene

    1991-08-01

    THE proteins encoded by the myc gene family are involved in the control of cell proliferation and differentiation, and aberrant expression of myc proteins has been implicated in the genesis of a variety of neoplasms1. In the carboxyl terminus, myc proteins have two domains that encode a basic domain/helix-loop-helix and a leucine zipper motif, respectively. These motifs are involved both in DNA binding and in protein dimerization2-5. In addition, myc protein family members share several regions of highly conserved amino acids in their amino termini that are essential for transformation6,7. We report here that an N-terminal domain present in both the c-myc and N-myc proteins mediates binding to the retinoblastoma gene product, pRb. We show that the human papilloma virus E7 protein competes with c-myc for binding to pRb, indicating that these proteins share overlapping binding sites on pRb. Furthermore, a mutant Rb protein from a human tumour cell line that carried a 35-amino-acid deletion in its C terminus failed to bind to c-myc. Our results suggest that c-myc and pRb cooperate through direct binding to control cell proliferation.

  12. 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

    using the peroxidase and DAB methods. The C-MYC protein expression was elevated in the cytoplasm and nuclei of the canine PCa and PIA compared with the normal prostate (P = 0.004. The NKX3.1 protein expression was reduced in 94.75% of the PCa and 100% of the PIA compared with the normal prostate (P = 0...

  13. Occurrence and expression of p53 suppressor gene and c-Myc oncogene in dog eyelid tumors.

    Science.gov (United States)

    Lopes, Rodrigo Antonio; Cardoso, Tereza Cristina; Luvizotto, Maria Cecília Rui; de Andrade, Alexandre Lima

    2010-03-01

    To detect the occurrence and expression of the suppressor gene p53 and of the oncogene c-Myc in eyelid tumors of dogs using the PCR, RT-PCR, PCR-ELISA and RT-PCR-ELISA techniques. These genes have not been described in dog eyelid tumors before. Nine samples of eyelid or third eyelid epithelial tumors were obtained from the archives of the Department of Veterinary Pathology. Tumor diagnosis was confirmed by evaluation of hematoxylin-eosin stained sections, and immunohistochemistry for cytokeratin AE1/AE3 and vimentin V9. A canine mammary tumor was used for positive control. Agarose gel electrophoresis, PCR-ELISA and RT-PCR-ELISA were used to detect p53 and c-Myc genes. The occurrence of p53 was detected in most of the eyelid tumors and third eyelid tumors studied (88.8%, n = 8) and was expressed in 75% of the positive samples, as indicated by ELISA. The c-Myc gene was found in 77.7% (n = 7) of the samples and was expressed in eight samples. Eyelid and third eyelid tumors of dogs express both the p53 and the c-Myc genes as shown by PCR and RT-PCR. However, PCR ELISA and RT-PCR ELISA were more efficient in assessing occurrence and expression of these genes because they identified amplified products that were not detected by agarose gel electrophoresis.

  14. A critical appraisal of the immunohistochemical detection of the c-myc oncogene product in colorectal cancer.

    Science.gov (United States)

    Jones, D. J.; Ghosh, A. K.; Moore, M.; Schofield, P. F.

    1987-01-01

    Expression of c-myc was studied immunohistochemically in 100 colorectal carcinomas, using a monoclonal antibody, Myc 1-6E10, which is purported to recognize the oncoprotein (p62c-myc) in paraffin-embedded material. In normal epithelium, maturing crypt cells and terminally differentiated surface cells were positive, and proliferating basal crypt cells negative. All carcinomas stained positively, but intensity was independent of histological differentiation, Dukes' stage, DNA ploidy and survival. Staining was predominantly cytoplasmic despite the suspected nuclear location of p62c-myc and there was considerable staining of fibroblasts. When staining was compared in frozen and paraffin-embedded sections fixed in different ways, different patterns were observed. Acetone-fixed frozen sections exhibited weak nuclear and cytoplasmic staining or were negative. In formol-saline fixed frozen sections, there was stronger predominantly nuclear staining. In paraffin-embedded sections staining was predominantly cytoplasmic. This study suggests that c-myc expression is enhanced in the majority of colorectal carcinomas and although independent of clinical behaviour, may be a common event in malignant transformation. However, since staining is affected by fixation and processing, data obtained using Myc 1-6E10 on routinely processed specimens should be interpreted with caution. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:3325094

  15. C-myc proto-oncogene amplification detected by polymerase chain reaction in archival human ovarian carcinomas.

    Science.gov (United States)

    Schreiber, G.; Dubeau, L.

    1990-01-01

    Polymerase chain reaction (PCR) technology was used to examine the state of amplification of the proto-oncogene c-myc in archival ovarian carcinomas. Sequences from the c-myc gene and from a control gene were amplified simultaneously by PCR and the ratios of the two products measured. The results provided an accurate measurement of the relative number of copies of the two genes in each tumor genome if the control and test sequences amplified by PCR were of equal lengths. The results were not affected by the number of PCR cycles used. This technique should facilitate gene amplification studies in clinical medicine. Increased c-myc copy number was found in 17% of the 30 cases examined when a control from the same chromosome as c-myc was used, but in 37% of cases if a control from another chromosome was used. This underlines the importance of the genetic location of the selected control genes for such studies. Images Figure 2 PMID:2205100

  16. Rapid loss of intestinal crypts upon conditional deletion of the Wnt/Tcf-4 target gene c-Myc.

    NARCIS (Netherlands)

    Muncan, V.; Sansom, O.J.; Tertoolen, L.; Phesse, T.J.; Begthel, H.; Sancho, E.; Cole, A.M.; Gregorieff, A.; Alboran, I.M. de; Clevers, J.C.; Clarke, A.R.

    2006-01-01

    Inhibition of the mutationally activated Wnt cascade in colorectal cancer cell lines induces a rapid G1 arrest and subsequent differentiation. This arrest can be overcome by maintaining expression of a single Tcf4 target gene, the proto-oncogene c-Myc. Since colorectal cancer cells share many

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

    Science.gov (United States)

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

    1990-01-01

    Consistent chromosomal translocations involving the c-myc cellular oncogene and one of the three immunoglobin loci are typical for human Burkitt's lymphoma, induced mouse plasmacytoma (MPC) and spontaneously arising rat immunocytoma (RIC). Another plasma cell malignancy, multiple myeloma (MM), arising spontaneously in the ageing C57BL/KaLwRij mice, was investigated in order to see whether the MM cells contain c-myc abnormalities of the MPC or RIC type. Rearrangement of the c-myc oncogene was found in the bone marrow cells only in 5T2 MM transplantation line in a mouse of the 24th generation and in none of the seven other MM of the 5T series which were of earlier generations. Since the mouse 5T MM resembles the human MM very closely, including the absence of consistent structural c-myc oncogene abnormalities, it can serve as a useful experimental model for studies on the aetiopathogenesis of this disease. Images Figure 2 Figure 3 PMID:2310679

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

    NARCIS (Netherlands)

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

    1993-01-01

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

  19. Isolation and characterization of c-myc, a cellular homolog of the oncogene (v-myc) of avian myelocytomatosis virus strain 29.

    Science.gov (United States)

    Vennstrom, B; Sheiness, D; Zabielski, J; Bishop, J M

    1982-01-01

    The chicken genome contains nucleotide sequences homologous to transforming genes (oncogenes) of a number of avian retroviruses. We have isolated chicken DNA (c-myc) that is homologous to the oncogene (v-myc) of the avian myelocytomatosis virus MC29 and have compared the structures of the cellular and viral genes. Results from restriction endonuclease mapping of c-myc and from analysis of heteroduplexes between the DNAs of the cellular and viral genes show that c-myc is homologous to 1,500 nucleotides in v-myc DNA. This homologous region is interrupted in c-myc by an intron-like sequence of 1,100 nucleotides which is absent from v-myc. Nuclear RNA from normal chicken cells contains at least five species of transcripts from c-myc ranging from 2.5 to 6.5 kilobases in length. By contrast, cytoplasm contains only the 2.5-kilobase c-myc RNA. These features of the c-myc gene and its nuclear transcripts are characteristic of normal cellular genes and suggest that the myc gene is of cellular rather than viral origin. The exons in c-myc may define two functional domains in the gene and may therefore facilitate the dissection of the different oncogenic potentials of the MC29 virus. Images PMID:6284994

  20. Candidate tumour suppressor CCDC19 regulates miR-184 direct targeting of C-Myc thereby suppressing cell growth in non-small cell lung cancers.

    Science.gov (United States)

    Liu, Zhen; Mai, Chunping; Yang, Huiling; Zhen, Yan; Yu, Xiaoli; Hua, Shengni; Wu, Qiangyun; Jiang, Qinping; Zhang, Yajie; Song, Xin; Fang, Weiyi

    2014-08-01

    We previously reported and revised the nasopharyngeal epithelium specific protein CCDC19 and identified it as a potential tumour suppressor in nasopharyngeal carcinoma. The purpose of this study was to investigate the involvement of CCDC19 in the pathogenesis of human non-small cell lung cancers (NSCLC). Down-regulated CCDC19 expression was observed in NSCLC tissues and cells compared to normal tissues. However, reduced protein expression did not correlate with the status of NSCLC progression. Instead, we observed that patients with lower CCDC19 expression had a shorter overall survival than did patients with higher CCDC19 expression. Lentiviral-mediated CCDC19 overexpression significantly suppressed cell proliferation and cell cycle transition from G1 to S and G2 phases in NSCLC cells. Knocking down CCDC19 expression significantly restored the ability of cell growth in CCDC19 overexpressing NSCLC cells. Mechanistically CCDC19 functions as a potential tumour suppressor by stimulating miR-184 suppression of C-Myc thus blocking cell growth mediated by the PI3K/AKT/C-Jun pathway. Our studies are the first to demonstrate that reduced expression of CCDC19 is an unfavourable factor in NSCLC. © 2014 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  1. Non-Hodgkin's lymphomas with Burkitt-like cells are associated with c-Myc amplification and poor prognosis.

    Science.gov (United States)

    Mossafa, H; Damotte, D; Jenabian, A; Delarue, R; Vincenneau, A; Amouroux, I; Jeandel, R; Khoury, E; Martelli, J M; Samson, T; Tapia, S; Flandrin, G; Troussard, X

    2006-09-01

    Out of 344 patients with newly diagnosed non-Hodgkin's lymphoma (NHL), this study identified 16 patients presenting Burkitt-like cells (BLCs) after cytological and/or histological review. Conventional cytogenetic analysis showed at diagnosis complex chromosomal abnormalities in 13 cases and a normal karyotype in three cases. However, neither t(8;14)(q24;q32) nor the variants t(2;8)(p12;q24) or t(8;22)(q24;q11) was detected. FISH studies showed c-MYC amplification in all cases with four to more than seven copies in 10 - 77% metaphase or inter-phase cells. This study did not observe any gene fusion signal for c-MYC/IgH excluding a t(8;14) translocation and partial tri or polysomy of chromosome 8. It also excluded in that cases a break apart for the c-MYC locus. This study also never detected IgL/c-MYC, IgK/c-MYC or X-c-MYC. The BLCs were present whatever the lymphoma sub-type: follicular lymphoma (FL) was diagnosed in six out of 16 patients, mantle cell lymphoma (MCL) in four out of 16 patients, marginal zone lymphoma (MZL) in two out of 16 patients and diffuse large B-cell lymphomas (DLBCL) in three out of 16 patients. One additional patient presented a T-cell lymphoma. The clinical course was aggressive with a poor prognosis, as death occurred in nine patients, within 6 months after diagnosis for eight of them. These data could suggest a sub-group of NHL patients (15 B-NHL, 1 T-NHL) have been identified with a poor prognosis characterized by the association of Burkitt-like cells and c-MYC amplification without t(8;14)(q24;q32) or its variants. The possibility that this profile may represent a distinct morphologic NHL sub-set remains to be determined on a large cohort of patients.

  2. 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.

  3. Astroglial expression of the P-glycoprotein is controlled by intracellular CNTF

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    Guillet Catherine

    2002-07-01

    Full Text Available Abstract Background The P-glycoprotein (P-gp, an ATP binding cassette transmembrane transporter, is expressed by astrocytes in the adult brain, and is positively modulated during astrogliosis. In a search for factors involved in this modulation, P-gp overexpression was studied in long-term in vitro astroglial cultures. Results Surprisingly, most factors that are known to induce astroglial activation in astroglial cultures failed to increase P-gp expression. The only effective proteins were IFNγ and those belonging to the IL-6 family of cytokines (IL-6, LIF, CT-1 and CNTF. As well as P-gp expression, the IL-6 type cytokines - but not IFNγ - stimulated the expression of endogenous CNTF in astrocytes. In order to see whether an increased intracellular level of CNTF was necessary for induction of P-gp overexpression by IL-6 type cytokines, by the same cytokines analysis was carried out on astrocytes obtained from CNTF knockout mice. In these conditions, IFNγ produced increased P-gp expression, but no overexpression of P-gp was observed with either IL-6, LIF or CT-1, pointing to a role of CNTF in the intracellular signalling pathway leading to P-gp overexpression. In agreement with this suggestion, application of exogenous CNTF -which is internalised with its receptor - produced an overexpression of P-gp in CNTF-deficient astrocytes. Conclusions These results reveal two different pathways regulating P-gp expression and activity in reactive astrocytes, one of which depends upon the intracellular concentration of CNTF. This regulation of P-gp may be one of the long searched for physiological roles of CNTF.

  4. Ammonia Affects Astroglial Proliferation in Culture.

    Directory of Open Access Journals (Sweden)

    Guillermo Bodega

    Full Text Available Primary cultures of rat astroglial cells were exposed to 1, 3 and 5 mM NH4Cl for up to 10 days. Dose- and time-dependent reductions in cell numbers were seen, plus an increase in the proportion of cells in the S phase. The DNA content was reduced in the treated cells, and BrdU incorporation diminished. However, neither ammonia nor ammonia plus glutamine had any effect on DNA polymerase activity. iTRAQ analysis showed that exposure to ammonia induced a significant reduction in histone and heterochromatin protein 1 expression. A reduction in cell viability was also noted. The ammonia-induced reduction of proliferative activity in these cultured astroglial cells seems to be due to a delay in the completion of the S phase provoked by the inhibition of chromatin protein synthesis.

  5. BIN1 reverses PD-L1-mediated immune escape by inactivating the c-MYC and EGFR/MAPK signaling pathways in non-small cell lung cancer.

    Science.gov (United States)

    Wang, J; Jia, Y; Zhao, S; Zhang, X; Wang, X; Han, X; Wang, Y; Ma, M; Shi, J; Liu, L

    2017-11-09

    Non-small cell lung cancer (NSCLC) is one of the most common and malignant carcinoma worldwide, and the incidence and mortality are increasing rapidly. Immunotherapy targeting programmed death 1/programmed death ligand 1 (PD-L1) signaling has shown prominent clinical effects in treating NSCLC; however, a poor understanding of the associated regulating molecular mechanisms of PD-L1 has become one of the biggest obstacles for further improving efficacy. Bridging integrator-1 (BIN1) can regulate numerous cancer-related molecules to exert multiple tumor-suppressing effects by either interacting or not interacting with c-MYC. In the present study, we observed that there exists a negative correlation between the expression of PD-L1 and BIN1 in NSCLC tissues. The expression levels of BIN1 and PD-L1 were significantly related to the tumor, lymph node and metastasis grade (TNM) stage, invasion range and lymph node metastasis. Simultaneously, for NSCLC patients, the expression statuses of BIN1 and PD-L1 might be independent prognostic factors. Furthermore, the expression of tumor-infiltrating lymphocytes was positively associated with BIN1 expression and negatively related to PD-L1 expression in NSCLC tissues. Importantly, we showed that PD-L1 was under the control of BIN1. In addition, the overexpression of BIN1 could inhibit the c-MYC and epithelial growth factor receptor (EGFR)-dependent PD-L1 expression and reverse the suppressive immuno-microenvironment in vivo. Taken together, our findings indicated that BIN1 restoration in NSCLC could reverse PD-L1-mediated immune escape by inactivating the c-MYC and EGFR/mitogen-activated protein kinase pathways.

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

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    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.

  7. 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.

  8. [Effect of isorhmnetin on circadian rhythms of DNA synthesis and expression of c-myc gene in Eca-109 cells of human oesophageal cancer].

    Science.gov (United States)

    Yang, Chunlei; Peng, Tao; Qu, Yi; Tao, Dachang; Wang, Zhengrong; Zhu, Bin

    2005-12-01

    This study was focused on the circadian rhythms of DNA synthesis and the expression of c-myc gene in untreated and treated Eca-109 cells in human oesophageal cancer with isorhmnetin. The circadian rhythms of 3H-TdR incorporation and expression of c-myc gene in untreated and treated Eca-109 cells were measured by 3H-thymidine uptake assay and flow cytometry. The data collected were analyzed by ANOVA and Cosinor method. DNA synthesis and expression of c-myc gene in untreated group varied according to circadian time with statistical significance, the distribution curves of both DNA synthesis and the expression level of c-myc were fit for cosinor changes. The circadian rhythms of DNA synthesis and circadian parameters of c-myc expression in treated Eca-109 cells changed. The circadian parameters of DNA synthesis and expression level of c-myc varied after treatment by isorhmnetin. The effects of isorhmnetin on cell proliferation and c-myc expression reached the highest level from 20: 00 to 0: 00. The results provide a guidance for instituting the chemotherapy and chronotherapy of human tumors, when isorhmnetin is for use as anti-cancer agent.

  9. The FUSE binding proteins FBP1 and FBP3 are potential c-myc regulators in renal, but not in prostate and bladder cancer

    Directory of Open Access Journals (Sweden)

    Meyer Hellmuth-Alexander

    2008-12-01

    Full Text Available Abstract Background The three far-upstream element (FUSE binding proteins (FBP1, FBP2, and FBP3 belong to an ancient family of single-stranded DNA binding proteins which are required for proper regulation of the c-myc proto-oncogene. Whereas it is known that c-myc alterations play a completely different role in various carcinomas of the urogenital tract, the relevance of FBPs is unclear. Methods FBP1, FBP3 and c-myc expression was studied in 105 renal cell, 95 prostate and 112 urinary bladder carcinomas by immunohistochemistry using tissue microarrays. Results High rates of FBP1 and FBP3 expression were observed in all cancer types. There was a concomitant up-regulation of FBP1 and FBP3 in renal cell and prostate carcinomas (p C-myc expression was detectable in 21% of prostate, 30% of renal and 34% of urothelial carcinomas. Interestingly, strong FBP1 and FBP3 expression was associated with c-myc up-regulation in clear cell renal cell carcinomas (p Conclusion The correlation between FBP1/FBP3, c-myc and high proliferation rate in renal cell carcinoma provides strong in vivo support for the suggested role of FBP1 and FBP3 as activators of c-myc. The frequent up-regulation of FBP1 and FBP3 in urothelial and prostate carcinoma suggests that FBPs also have an important function in gene regulation of these tumors.

  10. Activating and sustaining c-Myc by depletion of miR-144/451 gene locus contributes to B-lymphomagenesis.

    Science.gov (United States)

    Ding, Lan; Zhang, Yanqing; Han, Lingling; Fu, Lei; Mei, Xia; Wang, Jijun; Itkow, Jacobi; Elabid, Afaf Elabid Ibrahim; Pang, Lei; Yu, Duonan

    2017-12-29

    Hyper activity of protooncogene c-Myc is one of the hallmarks of highly aggressive lymphomas. However, the mechanism of how c-Myc is subjected to activation and amplification is still not well defined. In this study, we use gene knockout strategy to show that targeted depletion of a well-conserved microRNA gene locus miR-144/451 initiates tumorigenesis including B-lymphoma development in aged mice. This is due, at least in part, to the direct activation of the c-Myc gene by loss of miR-144/451 expression in hematopoietic cells. Moreover, oncoprotein c-Myc inversely regulates miR-144/451 expression by directly binding to the miR-144/451 promoter region, forming a miRNA-Myc positive feedback loop to safeguard the high level of c-Myc in B-lymphocytes. We also demonstrate that this miRNA-Myc crosstalk is disrupted in human diffuse large B-cell lymphomas with aberrant c-Myc expression. Therefore, our findings provide strong evidence, for the first time, that deficiency of miR-144/451 expression may play a bona fide role in derepression of silenced c-Myc, which contributes to tumor development including B-lymphomagenesis.

  11. Detection of C-MYC oncogene translocation and copy number change in the normal-dysplasia-carcinoma sequence of the larynx by fluorescence in situ hybridization.

    Science.gov (United States)

    Liu, Yu; Gong, Li-Ping; Dong, Xiao-Li; Liu, Hong-Gang

    2013-06-01

    The aim of this study was to determine the translocation and copy number change of the C-MYC gene in patients with laryngeal dysplasia and laryngeal squamous cell carcinoma (LSCC), and to evaluate the prevalence of such expression in relation to the normal-dysplasia-carcinoma sequence. Fluorescent in situ hybridization (FISH) was applied on formalin-fixed paraffin-embedded blocks of 93 laryngeal lesion specimens (14 normal epithelium, 15 mild dysplasia, 18 moderate dysplasia, 16 severe dysplasia, 9 carcinoma in situ, and 21 invasive carcinoma). C-MYC translocation was not observed in all laryngeal tissue. The high frequency for C-MYC copy-number increased (100%) in invasive carcinoma: 57.14% amplifications and 42.86% gains, and the positive rate of C-MYC amplification and copy-number change increased with the increasing severity of laryngeal lesions (P < 0.0001). The results suggest that C-MYC may be activated by gain/amplification in LSCC and precancerous lesions. Thus, C-MYC may play an important role in promoting LSCC progression, and early FISH detection of C-MYC may be exploited to set a screening test for laryngeal dysplasia. Copyright © 2012 Wiley Periodicals, Inc.

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

    Science.gov (United States)

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

    2012-01-01

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

  13. Effects of microRNA-24 targeting C-myc on apoptosis, proliferation and cytokine expressions in chondrocytes of rats with osteoarthritis via MAPK signaling pathway.

    Science.gov (United States)

    Wu, Yuan-Hao; Liu, Wei; Zhang, Lei; Liu, Xiao-Ya; Wang, Yi; Xue, Bin; Liu, Bin; Duan, Ran; Zhang, Bo; Ji, Yang

    2017-11-16

    To investigate whether microRNA-24 (miR-24) targeting C-myc affects chondrocytes of rats with osteoarthritis (OA) via the MAPK signaling pathway. Thirty rats were assigned as a sham group and an OA group (established as OA rat models by cutting the anterior cruciate ligaments and removing 1/3 medial meniscus). TUNEL staining and immunohistochemistry were conducted for cell apoptosis index (AI) and positive expression rate of C-myc protein. Enzyme-linked immuno sorbent assay (ELISA) was carried out for serum level of IL-1β and TNF-α. Primary chondrocytes were assigned into the blank, negative control (NC), miR-24 mimics, miR-24 inhibitors, siRNA-C-myc, and miR-24 inhibitors + siRNA-C-myc groups. The expressions of miR-24, C-myc, p38, ERK, JNK, IL-1β, and TNF-α in tissues and cells were detected using reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) and Western blotting. CCK8 assay and flow cytometry were performed for cell proliferation and apoptosis. The OA group showed higher IL-1β, TNF-α, AI, and C-myc than the sham group. C-myc is a target gene of miR-24. Compared with the blank group, the miR-24 mimics and siRNA-C-myc groups showed reduced expression of C-myc, IL-1β, TNF-α, p38, p-p38, ERK, p-ERK, JNK, and p-JNK, apoptosis rate yet increased cell proliferation; however, the miR-24 inhibitors group exhibited an opposite trend. The miR-24 inhibitors + siRNA-C-myc group presented a same tendency compared to the siRNA-C-myc group. Upregulated miR-24 downregulates C-myc could suppress apoptosis and promote proliferation of chondrocytes to prevent the occurrence and subsequent progression of OA via inactivating the MAPK signaling pathway. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

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

    Science.gov (United States)

    2015-10-01

    AWARD NUMBER: W81XWH-13-1-0162 TITLE: Using a Novel Transgenic Mouse Model to Study c-Myc Oncogenic Pathway in Castration Resistance and...TELEPHONE NUMBER (include area code) Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std. Z39.18 Using a Novel Transgenic Mouse Model to Study c-Myc... Transgenic Mouse Model to Study c-Myc Oncogenic Pathway in Castration Resistance and Chemoresistance of Prostate Cancer Feng Yang, Ph.D. Department of

  15. 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.

  16. Activation of nuclear β-catenin/c-Myc axis promotes oxidative stress injury in streptozotocin-induced diabetic cardiomyopathy.

    Science.gov (United States)

    Liu, Peng; Su, Jianfang; Song, Xixi; Wang, Shixiao

    2017-12-02

    Myocardial oxidative stress injury plays a crucial role in the pathogenesis of diabetic cardiomyopathy (DCM). Wnt/β-catenin signaling has been reported to involve in various heart diseases. However, the underlying mechanism associated with β-catenin in DCM remains elusive. This study intended to explore the effect of β-catenin on oxidative damage of DCM by establishing streptozotocin (STZ)-induced diabetic mouse model and hydrogen peroxide (H 2 O 2 )-treated myocardial cell model. Cardiac oxidative stress in DCM was detected by measurements of lipid peroxidation and anti-oxidative enzyme activities as well as DHE staining. Nuclear β-catenin activity and oxidative damage degree were measured by western blotting, qPCR, MTT assay and TUNEL staining. Cardiac function and morphology were evaluated by echocardiography and histopathology. Under diabetic oxidative stress or H 2 O 2 stimulation, nuclear β-catenin accumulation upregulated downstream c-Myc and further facilitated DNA damage and p53-mediated apoptosis as well as cell viability reduction, followed by phenotypic changes of cardiac dysfunction, interstitial fibrosis deposition and myocardial atrophy. Conversely, through directly inhibiting nuclear β-catenin/c-Myc axis, not only did siRNA knockdown of β-catenin or c-Myc attenuate cell injury in H 2 O 2 -stimulated cardiomyocytes, but also diabetic cardiac-specific β-catenin-knockout mice displayed the same prevention of heart injury as insulin-treated diabetic mice. The present study demonstrated that activated nuclear β-catenin/c-Myc axis was responsible for oxidative cardiac impairment of DCM. Therefore, repressing functional nuclear β-catenin may provide a hopeful therapeutic strategy for DCM. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. 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.

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

    Science.gov (United States)

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

    2014-01-01

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

  19. Tumor suppressor NDRG2 inhibits glycolysis and glutaminolysis in colorectal cancer cells by repressing c-Myc expression.

    Science.gov (United States)

    Xu, Xinyuan; Li, Jianying; Sun, Xiang; Guo, Yan; Chu, Dake; Wei, Li; Li, Xia; Yang, Guodong; Liu, Xinping; Yao, Libo; Zhang, Jian; Shen, Lan

    2015-09-22

    Cancer cells use glucose and glutamine as the major sources of energy and precursor intermediates, and enhanced glycolysis and glutamimolysis are the major hallmarks of metabolic reprogramming in cancer. Oncogene activation and tumor suppressor gene inactivation alter multiple intracellular signaling pathways that affect glycolysis and glutaminolysis. N-Myc downstream regulated gene 2 (NDRG2) is a tumor suppressor gene inhibiting cancer growth, metastasis and invasion. However, the role and molecular mechanism of NDRG2 in cancer metabolism remains unclear. In this study, we discovered the role of the tumor suppressor gene NDRG2 in aerobic glycolysis and glutaminolysis of cancer cells. NDRG2 inhibited glucose consumption and lactate production, glutamine consumption and glutamate production in colorectal cancer cells. Analysis of glucose transporters and the catalytic enzymes involved in glycolysis revealed that glucose transporter 1 (GLUT1), hexokinase 2 (HK2), pyruvate kinase M2 isoform (PKM2) and lactate dehydrogenase A (LDHA) was significantly suppressed by NDRG2. Analysis of glutamine transporter and the catalytic enzymes involved in glutaminolysis revealed that glutamine transporter ASC amino-acid transporter 2 (ASCT2) and glutaminase 1 (GLS1) was also significantly suppressed by NDRG2. Transcription factor c-Myc mediated inhibition of glycolysis and glutaminolysis by NDRG2. More importantly, NDRG2 inhibited the expression of c-Myc by suppressing the expression of β-catenin, which can transcriptionally activate C-MYC gene in nucleus. In addition, the growth and proliferation of colorectal cancer cells were suppressed significantly by NDRG2 through inhibition of glycolysis and glutaminolysis. Taken together, these findings indicate that NDRG2 functions as an essential regulator in glycolysis and glutaminolysis via repression of c-Myc, and acts as a suppressor of carcinogenesis through coordinately targeting glucose and glutamine transporter, multiple catalytic

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

    Czech Academy of Sciences Publication Activity Database

    Vališ, Karel; Talacko, Pavel; Grobárová, Valeria; Černý, J.; Novák, Petr

    2016-01-01

    Roč. 349, č. 2 (2016), s. 273-281 ISSN 0014-4827 R&D Projects: GA ČR(CZ) GP14-21095P; GA ČR GA13-16565S; GA MŠk(CZ) LQ1604; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61388971 Keywords : Hippo * Glycolysis * C-MYC Subject RIV: EE - Microbiology, Virology Impact factor: 3.546, year: 2016

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

    Directory of Open Access Journals (Sweden)

    Jinhui Wu

    2017-05-01

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

  2. Repression of PLA2R1 by c-MYC and HIF-2alpha promotes cancer growth.

    Science.gov (United States)

    Vindrieux, David; Devailly, Guillaume; Augert, Arnaud; Le Calvé, Benjamin; Ferrand, Mylène; Pigny, Pascal; Payen, Léa; Lambeau, Gérard; Perrais, Michael; Aubert, Sébastien; Simonnet, Hélène; Dante, Robert; Bernard, David

    2014-02-28

    Loss of secreted phospholipase A2 receptor (PLA2R1) has recently been found to render human primary cells more resistant to senescence whereas increased PLA2R1 expression is able to induce cell cycle arrest, cancer cell death or blockage of cancer cell transformation in vitro, suggesting that PLA2R1 displays tumor suppressive activities. Here we report that PLA2R1 expression strongly decreases in samples of human renal cell carcinoma (RCC). Knockdown of PLA2R1 increases renal cancer cell tumorigenicity supporting a role of PLA2R1 loss to promote in vivo RCC growth. Most RCC result from Von Hippel-Lindau (VHL) tumor suppressor loss-of-function and subsequent gain-of-function of the oncogenic HIF-2alpha/c-MYC pathway. Here, by genetically manipulating VHL, HIF-2alpha and c-MYC, we demonstrate that loss of VHL, stabilization of HIF-2alpha and subsequent increased c-MYC activity, binding and transcriptional repression, through induction of PLA2R1 DNA methylation closed to PLA2R1 transcriptional start site, results in decreased PLA2R1 transcription. Our results describe for the first time an oncogenic pathway leading to PLA2R1 transcriptional repression and the importance of this repression for tumor growth.

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

    Directory of Open Access Journals (Sweden)

    Silvi Kintawati

    2008-12-01

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

  4. 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.

  5. Inducement of G-quadruplex DNA forming and down-regulation of oncogene c-myc by bile acid-amino acid conjugate-BAA.

    Science.gov (United States)

    Tian, Mingyue; Zhang, Xiufeng; Li, Yan; Ju, Yong; Xiang, Junfeng; Zhao, Changqi; Tang, Yalin

    2010-03-01

    Human c-myc gene is a central regulator of cellular proliferation and cell growth, and G-quadruplexes have been proven to be the transcriptional controller of this gene. In this study, the interaction of bile acid-amino acid conjugate (BAA) with G-quadruplexes in c-myc was investigated by circular dichroism spectroscopy, nuclear magnetic resonance (NMR) measurement, and quantitative real-time polymerase chain reaction (PCR) assay. The experimental results indicated that BAA has the ability to selectively induce the formation of parallel G-quadruplexes in c-myc, which leads to down-regulation of c-myc transcription in the human breast cancer cell MCF-7.

  6. 9-N-Substituted berberine derivatives: stabilization of G-quadruplex DNA and down-regulation of oncogene c-myc.

    Science.gov (United States)

    Ma, Yan; Ou, Tian-Miao; Hou, Jin-Qiang; Lu, Yu-Jing; Tan, Jia-Heng; Gu, Lian-Quan; Huang, Zhi-Shu

    2008-08-15

    A series of 9-N-substituted berberine derivatives (2a-j) were synthesized and evaluated as a new class of G-quadruplex binding ligands. G-quadruplex of DNA had been proven to be the transcription controller of human c-myc gene. The interaction of 9-N-substituted berberine derivatives with G-quadruplex DNA in c-myc was examined via EMSA, CD spectroscopy, FRET-melting method, PCR-stop assay, competitive dialysis, cell proliferation assay, and RT-PCR assay. The experiment results indicated that these derivatives could selectively induce and stabilize the formation of intramolecular parallel G-quadruplex in c-myc, which led to down-regulation of transcription of the c-myc in the HL60 lymphomas cell line. The related structure-activity relationships were also discussed.

  7. A re-emerging marker for prognosis in hepatocellular carcinoma: the add-value of fishing c-myc gene for early relapse.

    Science.gov (United States)

    Pedica, Federica; Ruzzenente, Andrea; Bagante, Fabio; Capelli, Paola; Cataldo, Ivana; Pedron, Serena; Iacono, Calogero; Chilosi, Marco; Scarpa, Aldo; Brunelli, Matteo; Tomezzoli, Anna; Martignoni, Guido; Guglielmi, Alfredo

    2013-01-01

    Hepatocellular carcinoma is one leading cause of cancer-related death and surgical resection is still one of the major curative therapies. Recently, there has been a major effort to find mechanisms involved in carcinogenesis and early relapse. c-myc gene abnormality is found in hepatocarcinogenesis. Our aim was to analyze the role of c-myc as prognostic factor in terms of overall survival and disease-free survival and to investigate if c-myc may be an important target for therapy. We studied sixty-five hepatocellular carcinomas submitted to surgical resection with curative intent. Size, macro-microvascular invasion, necrosis, number of nodules, grading and serum alfa-fetoprotein level were registered for all cases. We evaluated the c-myc aberrations by using break-apart FISH probes. Probes specific for the centromeric part of chromosome 8 and for the locus specific c-myc gene (8q24) were used to assess disomy, gains of chromosomes (polysomy due to polyploidy) and amplification. c-myc gene amplification was scored as 8q24/CEP8 > 2. Statistical analysis for disease-free survival and overall survival were performed. At molecular level, c-myc was amplified in 19% of hepatocellular carcinoma, whereas showed gains in 55% and set wild in 26% of cases. The 1- and 3-year disease-free survival and overall survival for disomic, polysomic and amplified groups were significantly different (p=0.020 and p=.018 respectively). Multivariate analysis verified that the AFP and c-myc status (amplified vs. not amplified) were significant prognostic factors for overall patients survival. c-myc gene amplification is significantly correlated with disease-free survival and overall survival in patients with hepatocellular carcinoma after surgical resection and this model identifies patients with risk of early relapse (≤12 months). We suggest that c-myc assessment may be introduced in the clinical practice for improving prognostication (high and low risk of relapse) routinely and may have

  8. A re-emerging marker for prognosis in hepatocellular carcinoma: the add-value of fishing c-myc gene for early relapse.

    Directory of Open Access Journals (Sweden)

    Federica Pedica

    Full Text Available Hepatocellular carcinoma is one leading cause of cancer-related death and surgical resection is still one of the major curative therapies. Recently, there has been a major effort to find mechanisms involved in carcinogenesis and early relapse. c-myc gene abnormality is found in hepatocarcinogenesis. Our aim was to analyze the role of c-myc as prognostic factor in terms of overall survival and disease-free survival and to investigate if c-myc may be an important target for therapy. We studied sixty-five hepatocellular carcinomas submitted to surgical resection with curative intent. Size, macro-microvascular invasion, necrosis, number of nodules, grading and serum alfa-fetoprotein level were registered for all cases. We evaluated the c-myc aberrations by using break-apart FISH probes. Probes specific for the centromeric part of chromosome 8 and for the locus specific c-myc gene (8q24 were used to assess disomy, gains of chromosomes (polysomy due to polyploidy and amplification. c-myc gene amplification was scored as 8q24/CEP8 > 2. Statistical analysis for disease-free survival and overall survival were performed. At molecular level, c-myc was amplified in 19% of hepatocellular carcinoma, whereas showed gains in 55% and set wild in 26% of cases. The 1- and 3-year disease-free survival and overall survival for disomic, polysomic and amplified groups were significantly different (p=0.020 and p=.018 respectively. Multivariate analysis verified that the AFP and c-myc status (amplified vs. not amplified were significant prognostic factors for overall patients survival. c-myc gene amplification is significantly correlated with disease-free survival and overall survival in patients with hepatocellular carcinoma after surgical resection and this model identifies patients with risk of early relapse (≤12 months. We suggest that c-myc assessment may be introduced in the clinical practice for improving prognostication (high and low risk of relapse routinely

  9. Cytoplasmic calcium increase via fusion with inactivated Sendai virus induces apoptosis in human multiple myeloma cells by downregulation of c-Myc oncogene.

    Science.gov (United States)

    Jiang, Yingzhe; Saga, Kotaro; Miyamoto, Yasuhide; Kaneda, Yasufumi

    2016-06-14

    Because the emergence of drug resistance is a major limitation of current treatments for multiple myeloma (MM), it is necessary to continuously develop novel anticancer strategies. Here, using an inactivated Sendai virus (Hemagglutinating Virus of Japan; HVJ) envelope (HVJ-E), we discovered that increase of cytoplasmic Ca2+ by virus-cell fusion significantly induced apoptosis against human MM cells but not peripheral blood mononuclear cells from healthy donors. Interaction of F protein of HVJ-E with MM cells increased intracellular Ca2+ level of MMs by the induction of Ca2+ efflux from endoplasmic reticulum but not influx from extracellular region. The elevation of the Ca2+ cytoplasmic level induced SMAD1/5/8 phosphorylation and translocation into the nucleus, and SMAD1/5/8 and SMAD4 complex suppressed c-Myc transcription. Meanwhile, HVJ-E decreases S62 phosphorylation of c-Myc and promotes c-Myc protein degradation. Thus, HVJ-E-induced cell death of MM resulted from suppression of c-Myc by both destabilization of c-Myc protein and downregulation of c-Myc transcription. This study indicates that HVJ-E will be a promising tool for MM therapy.

  10. SAP155-mediated splicing of FUSE-binding protein-interacting repressor serves as a molecular switch for c-myc gene expression.

    Science.gov (United States)

    Matsushita, Kazuyuki; Kajiwara, Toshiko; Tamura, Mai; Satoh, Mamoru; Tanaka, Nobuko; Tomonaga, Takeshi; Matsubara, Hisahiro; Shimada, Hideaki; Yoshimoto, Rei; Ito, Akihiro; Kubo, Shuji; Natsume, Tohru; Levens, David; Yoshida, Minoru; Nomura, Fumio

    2012-06-01

    The Far UpStream Element (FUSE)-binding protein-interacting repressor (FIR), a c-myc transcriptional suppressor, is alternatively spliced removing the transcriptional repression domain within exon 2 (FIRΔexon2) in colorectal cancers. SAP155 is a subunit of the essential splicing factor 3b (SF3b) subcomplex in the spliceosome. This study aims to study the significance of the FIR-SAP155 interaction for the coordination of c-myc transcription, pre-mRNA splicing, and c-Myc protein modification, as well as to interrogate FIRΔexon2 for other functions relating to altered FIR pre-mRNA splicing. Knockdown of SAP155 or FIR was used to investigate their reciprocal influence on each other and on c-myc transcription, pre-mRNA splicing, and protein expression. Pull down from HeLa cell nuclear extracts revealed the association of FIR, FIRΔexon2, and SF3b subunits. FIR and FIRΔexon2 were coimmunoprecipitated with SAP155. FIR and FIRΔexon2 adenovirus vector (Ad-FIR and Ad-FIRΔexon2, respectively) were prepared to test for their influence on c-myc expression. FIR, SAP155, SAP130, and c-myc were coordinately upregulated in human colorectal cancer. These results reveal that SAP155 and FIR/FIRΔexon2 form a complex and are mutually upregulating. Ad-FIRΔexon2 antagonized Ad-FIR transcriptional repression of c-myc in HeLa cells. Because FIRΔexon2 still carries RRM1 and RRM2 and binding activity to FUSE, it is able to displace repression competent FIR from FUSE in electrophoretic mobility shift assays, thus thwarting FIR-mediated transcriptional repression by FUSE. Thus aberrant FIRΔexon2 production in turn sustained c-Myc expression. In conclusion, altered FIR and c-myc pre-mRNA splicing, in addition to c-Myc expression by augmented FIR/FIRΔexon2-SAP155 complex, potentially contribute to colorectal cancer development. 2012 AACR

  11. Sensitive electrochemiluminescence detection of c-Myc mRNA in breast cancer cells on a wireless bipolar electrode.

    Science.gov (United States)

    Wu, Mei-Sheng; Qian, Guang-sheng; Xu, Jing-Juan; Chen, Hong-Yuan

    2012-06-19

    We report an ultrasensitive wireless electrochemiluminescence (ECL) protocol for the detection of a nucleic acid target in tumor cells on an indium tin oxide bipolar electrode (BPE) in a poly(dimethylsiloxane) microchannel. The approach is based on the modification of the anodic pole of the BPE with antisense DNA as the recognition element, Ru(bpy)(3)(2+)-conjugated silica nanoparticles (RuSi@Ru(bpy)(3)(2+)) as the signal amplification tag, and reporter DNA as a reference standard. It employs the hybridization-induced changes of RuSi@Ru(bpy)(3)(2+) ECL efficiency for the specific detection of reporter DNA released from tumor cells. Prior to ECL detection, tumor cells are transfected with CdSe@ZnS quantum dot (QD)-antisense DNA/reporter DNA conjugates. Upon the selective binding of antisense DNA probes to intracellular target mRNA, reporter DNA will be released from the QDs, which indicates the amount of the target mRNA. The proof of concept is demonstrated using a proto-oncogene c-Myc mRNA in MCF-7 cells (breast cancer cell line) as a model target. The wireless ECL biosensor exhibited excellent ECL signals which showed a good linear range over 2 × 10(-16) to 1 × 10(-11) M toward the reporter DNA detection and could accurately quantify c-Myc mRNA copy numbers in living cells. C-Myc mRNA in each MCF-7 cell and LO2 cell was estimated to be 2203 and 13 copies, respectively. This wireless ECL strategy provides great promise in a miniaturized device and may facilitate the achievement of point of care testing.

  12. 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

  13. Target guided synthesis using DNA nano-templates for selectively assembling a G-quadruplex binding c-MYC inhibitor

    Science.gov (United States)

    Panda, Deepanjan; Saha, Puja; Das, Tania; Dash, Jyotirmayee

    2017-07-01

    The development of small molecules is essential to modulate the cellular functions of biological targets in living system. Target Guided Synthesis (TGS) approaches have been used for the identification of potent small molecules for biological targets. We herein demonstrate an innovative example of TGS using DNA nano-templates that promote Huisgen cycloaddition from an array of azide and alkyne fragments. A G-quadruplex and a control duplex DNA nano-template have been prepared by assembling the DNA structures on gold-coated magnetic nanoparticles. The DNA nano-templates facilitate the regioselective formation of 1,4-substituted triazole products, which are easily isolated by magnetic decantation. The G-quadruplex nano-template can be easily recovered and reused for five reaction cycles. The major triazole product, generated by the G-quadruplex inhibits c-MYC expression by directly targeting the c-MYC promoter G-quadruplex. This work highlights that the nano-TGS approach may serve as a valuable strategy to generate target-selective ligands for drug discovery.

  14. Quadruplex forming promoter region of c-myc oncogene as a potential target for a telomerase inhibitory plant alkaloid, chelerythrine.

    Science.gov (United States)

    Ghosh, Saptaparni; Dasgupta, Dipak

    2015-03-27

    Guanine rich sequences present in the promoter region of oncogenes could fold into G-quadruplexes and modulate transcription. Equilibrium between folding and unfolding of the quadruplexes in these regions play important role in disease processes. We have studied the effect of a putative anticancer agent chelerythrine on G-rich NHE III1 present in the promoter region of c-myc oncogene. We have demonstrated the ability of chelerythrine, a telomerase inhibitor, to block the hybridization of Pu27 with its complementary strand via folding it into a quadruplex structure. Calorimetry shows that the association of Pu27 with chelerythrine is primarily enthalpy driven with high binding affinity (∼10(5) M(-1)). The association does not lead to any major structural perturbation of Pu27. The resulting 2:1 complex has enhanced stability as compared to free Pu27. Another notable feature is that the presence of molecular crowding agent like ficoll 70 does not change the mode of recognition though the binding affinity decreases. We suggest that the anticancer activity of chelerythrine could be ascribed to its ability to stabilize the quadruplex structure in the c-myc promoter region thereby downregulating its transcription. Copyright © 2015 Elsevier Inc. All rights reserved.

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

    Science.gov (United States)

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

    2017-10-01

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

  16. I-motif structures formed in the human c-MYC promoter are highly dynamic--insights into sequence redundancy and I-motif stability.

    Directory of Open Access Journals (Sweden)

    Jixun Dai

    Full Text Available The GC-rich nuclease hypersensitivity element III1 (NHE III1 of the c-MYC promoter largely controls the transcriptional activity of the c-MYC oncogene. The C-rich strand in this region can form I-motif DNA secondary structures. We determined the folding pattern of the major I-motif formed in the NHE III1, which can be formed at near-neutral pH. While we find that the I-motif formed in the four 3' consecutive runs of cytosines appears to be the most favored, our results demonstrate that the C-rich strand of the c-MYC NHE III1 exhibits a high degree of dynamic equilibration. Using a trisubstituted oligomer of this region, we determined the formation of two equilibrating loop isomers, one of which contains a flipped-out cytosine. Our results indicate that the intercalative cytosine+-cytosine base pairs are not always necessary for an intramolecular I-motif. The dynamic character of the c-MYC I-motif is intrinsic to the NHE III1 sequence and appears to provide stability to the c-MYC I-motif.

  17. Transcriptional regulation of microsomal prostaglandin E synthase 1 by the proto-oncogene, c-myc, in the pathogenesis of inflammation and cancer.

    Science.gov (United States)

    Ramanan, M; Pilli, V S; Aradhyam, G K; Doble, M

    2017-01-22

    Pro-inflammatory molecules play a key role in the progression of various types of cancers highlighting the importance of studying the pathways that regulate the inflammatory cytokine production. To this end, prostaglandins have been reported to correlate with exacerbated cancer phenotypes that may be prevented by using anti-inflammatory drugs in humans. To understand how the prostaglandin E synthase 1 (mPGES1) may be regulated we analyzed its promoter sequence and identified myc-binding sites. Functional validation was performed by mutating the sites that led to attenuated promoter activation of mPGES1. The known c-myc inhibitor (10058-F4) also blocked PGE2 activity, indicating the importance of c-Myc in PGE2 synthesis. Isocoumarin analogs were able to reduce the expressions of both c-myc as well as mPGES1 and also inhibit the production of PGE2. Based on these data and the well-established role of c-myc in oncogenesis, we have demonstrated an additional role of c-myc in exacerbating cancers via PGE2 production, which may provide a therapeutic opportunity to treat these diseases. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Post-transcriptional control of c-myc proto-oncogene expression by glucocorticoid hormones in human T lymphoblastic leukemia cells

    Energy Technology Data Exchange (ETDEWEB)

    Maroder, M.; Vacca, A.; Screpanti, I.; Petrangeli, E.; Frati, L. (Univ. La Sapienza, Roma (Italy)); Martinotti, S.; Gulino, A. (Univ. of L' Aquila (Italy))

    1990-03-11

    The authors have studied the regulation of the human c-myc proto-oncogene by glucocorticoid hormones in T lymphoblastic leukemic cells. A significant decrease (50%) of the steady state levels of c-myc mRNA was observed as early as 3 hours after dexamethasone treatment of CEM-1.3 human lymphoma cells, reaching less than 5% values, with respect to untreated cells, 24 hours after hormone administration. Nuclear run-on experiments showed no modifications of the transcriptional rate from the first exon. However, a slight decrease (15%) of the transcript elongation from the first exon/first intron boundary was observed in the dexamethasone-treated cells. Using actinomycin D to block gene transcription, they observed a significant increase in the rate of c-myc RNA specific decay after dexamethasone treatment. The data suggest that dexamethasone is able to inhibit human c-myc gene expression primarily at the post-transcriptional level, through the synthesis of hormone-transcriptional level, through the synthesis of hormone-induced regulatory protein(s) controlling c-myc transcript stability.

  19. Far upstream element-binding protein-1, a novel caspase substrate, acts as a cross-talker between apoptosis and the c-myc oncogene.

    Science.gov (United States)

    Jang, M; Park, B C; Kang, S; Chi, S-W; Cho, S; Chung, S J; Lee, S C; Bae, K-H; Park, S G

    2009-03-26

    Far upstream element-binding protein-1 (FBP-1) binds to an upstream element of the c-myc promoter and regulates the c-myc mRNA level. Earlier, FBP-1 was identified as a candidate substrate of caspase-7. Here, we report that FBP-1 is cleaved by executor caspases, both in vitro and during apoptosis. Cleavage occurs at the caspase consensus site (DQPD(74)) located within the classical bipartite nuclear localization signal sequence. In cells subjected to apoptotic stimuli, the caspase-mediated cleavage of FBP-1 leads to its decreased presence in the nucleus, concomitant with the marked downregulation of c-Myc and its various target proteins. By contrast, cells transfected with a non-cleavable mutant of FBP-1 (D74A) maintain higher levels of c-Myc and are protected from apoptosis. On the basis of these results, we suggest that the oncogenic potential of c-Myc is 'switched off' after apoptosis induction as a consequence of the caspase-mediated cleavage of FBP-1.

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

    DEFF Research Database (Denmark)

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

    2012-01-01

    that is critical for ras transformation in murine embryonic fibroblasts. This cascade is coordinated by ERK and JNK2 MAPKs, whose Ras-mediated activation leads to the enhanced levels of three oncogenic transcription factors, namely, c-Myc, activating transcription factor 2 (ATF2) and ATF3, all of which...... are essential for ras transformation. Previous studies show that ERK-mediated serine 62 phosphorylation protects c-Myc from proteasomal degradation. ERK is, however, not alone sufficient to stabilize c-Myc but requires the cooperation of cancerous inhibitor of protein phosphatase 2A (CIP2A), an oncogene......Ras is one of the most frequently activated oncogenes in cancer. Two mitogen-activated protein kinases (MAPKs) are important for ras transformation: extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase 2 (JNK2). Here we present a downstream signal amplification cascade...

  1. A balance between self-renewal and commitment in the murine erythroleukemia cells with the transferred c-myc gene; an in vitro stochastic model.

    Science.gov (United States)

    Yamamoto, T; Masuko, K; Takada, S; Kume, T U; Obinata, M

    1989-11-01

    When murine erythroleukemia (MEL) cells, having the transferred rat c-myc gene under the control of human metallothionein II gene promoter, are induced to differentiate with dimethyl sulfoxide (DMSO), the level of differentiation is dependent on the c-myc levels which are modulated by the Zn++ ion. The clonal transformant cell line (38-2) can continuously grow in the presence of both DMSO and Zn++ ion. The proportion of differentiated cells in a population of the continuous culture is strongly affected by the concentration of Zn++ ions. These results suggested that a balance between self-renewal and commitment to differentiation of MEL cells is determined by the c-myc level, and that this cell line may be suitable for studying the stochastic process of growth and differentiation of hemopoietic stem cells.

  2. Regulation of the equilibrium between G-quadruplex and duplex DNA in promoter of human c-myc oncogene by a pyrene derivative.

    Science.gov (United States)

    Zhang, Zhenjiang; He, Xiangwei; Yuan, Gu

    2011-12-01

    It has been established that the equilibrium between duplex and G-quadruplex of the nuclease hypersensitivity element III1 (NHE III1) in human c-myc promoter is linked with this gene's transcription. Using NMR and ESI-MS, we have found a pyrene derivative, DMAPP, is able to modulate this equilibrium and, thus, might have the potential to regulate this oncogene's transcription. DMAPP has shown as a G-quadruplex binding agent and could induce c-myc G-quadruplex formation out of duplex. These results provide new clue for rational drug design to target transcription control of c-myc. Copyright © 2011 Elsevier B.V. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

    Beecham, E.J.; Mushinski, J.F.; Shacter, E.; Potter, M.; Bohr, V.A. (Laboratory of Molecular Pharmacology, National Cancer Institute, Bethesda, MD (USA))

    1991-06-01

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

  4. B-cell activating factor and v-Myc myelocytomatosis viral oncogene homolog (c-Myc) influence progression of chronic lymphocytic leukemia.

    Science.gov (United States)

    Zhang, Weizhou; Kater, Arnon P; Widhopf, George F; Chuang, Han-Yu; Enzler, Thomas; James, Danelle F; Poustovoitov, Maxim; Tseng, Ping-Hui; Janz, Siegfried; Hoh, Carl; Herschman, Harvey; Karin, Michael; Kipps, Thomas J

    2010-11-02

    Mice bearing a v-Myc myelocytomatosis viral oncogene homolog (c-Myc) transgene controlled by an Ig-alpha heavy-chain enhancer (iMyc(Cα) mice) rarely develop lymphomas but instead have increased rates of memory B-cell turnover and impaired antibody responses to antigen. We found that male progeny of iMyc(Cα) mice mated with mice transgenic (Tg) for CD257 (B-cell activating factor, BAFF) developed CD5(+) B-cell leukemia resembling human chronic lymphocytic leukemia (CLL), which also displays a male gender bias. Surprisingly, leukemic cells of Myc/Baff Tg mice expressed higher levels of c-Myc than did B cells of iMyc(Cα) mice. We found that CLL cells of many patients with progressive disease also expressed high amounts of c-MYC, particularly CLL cells whose survival depends on nurse-like cells (NLC), which express high-levels of BAFF. We find that BAFF could enhance CLL-cell expression of c-MYC via activation the canonical IκB kinase (IKK)/NF-κB pathway. Inhibition of the IKK/NF-κB pathway in mouse or human leukemia cells blocked the capacity of BAFF to induce c-MYC or promote leukemia-cell survival and significantly impaired disease progression in Myc/Baff Tg mice. This study reveals an important relationship between BAFF and c-MYC in CLL which may affect disease development and progression, and suggests that inhibitors of the canonical NF-κB pathway may be effective in treatment of patients with this disease.

  5. Resveratrol prevents ammonia toxicity in astroglial cells.

    Directory of Open Access Journals (Sweden)

    Larissa Daniele Bobermin

    Full Text Available Ammonia is implicated as a neurotoxin in brain metabolic disorders associated with hyperammonemia. Acute ammonia toxicity can be mediated by an excitotoxic mechanism, oxidative stress and nitric oxide (NO production. Astrocytes interact with neurons, providing metabolic support and protecting against oxidative stress and excitotoxicity. Astrocytes also convert excess ammonia and glutamate into glutamine via glutamine synthetase (GS. Resveratrol, a polyphenol found in grapes and red wines, exhibits antioxidant and anti-inflammatory properties and modulates glial functions, such as glutamate metabolism. We investigated the effect of resveratrol on the production of reactive oxygen species (ROS, GS activity, S100B secretion, TNF-α, IL-1β and IL-6 levels in astroglial cells exposed to ammonia. Ammonia induced oxidative stress, decreased GS activity and increased cytokines release, probably by a mechanism dependent on protein kinase A (PKA and extracellular signal-regulated kinase (ERK pathways. Resveratrol prevented ammonia toxicity by modulating oxidative stress, glial and inflammatory responses. The ERK and nuclear factor-κB (NF-κB are involved in the protective effect of resveratrol on cytokines proinflammatory release. In contrast, other antioxidants (e.g., ascorbic acid and trolox were not effective against hyperammonemia. Thus, resveratrol could be used to protect against ammonia-induced neurotoxicity.

  6. Control of c-fos and c-myc proto-oncogene induction in rat thyroid cells in culture

    Energy Technology Data Exchange (ETDEWEB)

    Isozaki, O.; Kohn, L.D. (National Institute of Diabetes, Digestive and Kidney Diseases, Bethesda, MD (USA))

    1987-11-01

    Removal of TSH, insulin, and cortisol from the medium, and decreasing the serum content to 0.2%, abolishes both the proliferate and differentiated state of FRTL-5 rat thyroid cells in culture. In these basal conditions, the individual addition of TSH, insulin, insulin-like growth factor-I (IGF-I), phorbol 12-myristate 13-acetate (TPA), alpha 1-adrenergic agents, or A23187, increase c-myc and/or c-fos proto-oncogene expression. Under the same conditions, only the addition of TSH increased cAMP levels; 8-bromo-cAMP can increase c-myc or c-fos mRNA levels. Pretreatment of cells with phorbol 12,13-dibutyrate, an agent which down regulates the C-kinase, completely inhibits the effect of TPA on proto-oncogene expression but has no affect on the A23187 induced-increase. The sum of these results indicate that at least four separate signal systems independently increase c-myc or c-fos gene expression in FRTL-5 cells cAMP (TSH), C-kinase (TPA), Ca++/phosphoinositide (A23187), and that influenced by insulin/IGF-I. None of the ligands, when individually returned to cells in basal medium (no TSH, insulin, or cortisol and only 0.2% serum), increases cell number; norepinephrine, and A23187 do not increase (3H)thymidine incorporation into DNA under these conditions; and combinations of the ligands can be more than additive in effecting (3H)thymidine incorporation into DNA but are only additive in effecting proto-oncogene expression. Insulin/IGF-I plus TSH or insulin/IGF-I plus norepinephrine can increase both proto-oncogene expression and (3H)thymidine incorporation into DNA to the same extent; however, the former combination can increase cell number whereas the latter cannot. There is therefore no simple correlation between the ability of the above ligands to increase proto-oncogene expression and their ability to increase cell number or induce DNA synthesis.

  7. MicroRNA-184 inhibits proliferation and promotes apoptosis of human colon cancer SW480 and HCT116 cells by downregulating C-MYC and BCL-2.

    Science.gov (United States)

    Wang, Yong-Bing; Zhao, Xiao-Hui; Li, Gang; Zheng, Jun-Hua; Qiu, Wei

    2018-02-01

    This study aimed to investigate the effects of microRNA-184 (miR-184) on the proliferation and apoptosis of human colon cancer cells through the regulation of C-MYC and BCL-2. Human colon cancer tissues were selected as case group, and adjacent normal tissues were as control group. Human colon cancer SW480 and HCT116 cells were allocated into blank, miR-184 mimic negative control (mimic-NC), miR-184 inhibitor NC (inhibitor-NC), miR-184 mimic, and miR-184 inhibitor groups. Flow cytometry, Annexin V/PI and MTT assay were used to examine the cell cycle, apoptosis and viability. The expressions of C-MYC, BCL-2 and miR-184 were detected via immunohistochemistry, Western blotting and reverse transcription quantitative polymerase chain reaction (RT-qPCR). C-MYC and BCL-2 were direct targets to miR-184. The growth of colon cancer cells in the miR-184 mimic group was inhibited and exhibited an increase in apoptosis. Cell growth in the miR-184 mimic group was increased in addition to the inhibition of apoptosis. Compared with miR-184 mimic group, the expressions of C-MYC and BCL-2 in miR-184 inhibitor group were increased. The expressions of C-MYC and BCL-2 in colon cancer tissues exhibited high levels of expression, while miR-184 displayed relatively low levels in comparison to the adjacent normal tissues. An association was detected regarding the expressions of miR-184, C-MYC and BCL-2 with the differentiation, invasion depth and lymph node metastasis. MiR-184 expression was negatively related to C-MYC and BCL-2 expressions. Our study suggested that miR-184 could inhibit proliferation and promote apoptosis of colon cancer cells by down-regulating expressions of C-MYC and BCL-2. © 2017 Wiley Periodicals, Inc.

  8. 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

  9. Changes in the gene expression of C-myc and CD38 in HL-60 cells during differentiation induced by nicotinic acid-related compounds.

    Science.gov (United States)

    Ida, Chieri; Ogata, Shin; Okumura, Katsuzumi; Taguchi, Hiroshi

    2008-03-01

    Changes in gene expression levels of c-myc and CD38 were examined during the differentiation of HL-60 cells to granulocytes due to three nicotinic acid-related compounds. CD38 expression was increased by isonicotinic acid and all-trans-retinoic acid (ATRA). Nicotinamide and nicotinamide N-oxide drastically decreased c-myc expression, but isonicotinic acid had no effect, suggesting that these compounds differentiate HL-60 to granulocytes through different pathways. These results should provide useful information as to the mechanisms of cell differentiation.

  10. 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.

  11. 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...

  12. Nucleolus disassembly in mitosis and apoptosis: dynamic redistribution of phosphorylated-c-Myc, fibrillarin and Ki-67

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    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.

  13. The Proto-Oncogene c-myc Is a Direct Target Gene of Epstein-Barr Virus Nuclear Antigen 2

    Science.gov (United States)

    Kaiser, Carmen; Laux, Gerhard; Eick, Dirk; Jochner, Nicola; Bornkamm, Georg W.; Kempkes, Bettina

    1999-01-01

    Epstein-Barr virus (EBV) infects and transforms primary B lymphocytes in vitro. Viral infection initiates the cell cycle entry of the resting B lymphocytes. The maintenance of proliferation in the infected cells is strictly dependent on functional EBNA2. We have recently developed a conditional immortalization system for EBV by rendering the function of EBNA2, and thus proliferation of the immortalized cells, dependent on estrogen. This cellular system was used to identify early events preceding induction of proliferation. We show that LMP1 and c-myc are directly activated by EBNA2, indicating that all cellular factors essential for induction of these genes by EBNA2 are present in the resting cells. In contrast, induction of the cell cycle regulators cyclin D2 and cdk4 are secondary events, which require de novo protein synthesis. PMID:10196351

  14. Astroglial MicroRNA-219-5p in the Ventral Tegmental Area Regulates Nociception in Rats.

    Science.gov (United States)

    Zhang, Song; Yang, Xiao-Na; Zang, Ting; Luo, Jun; Pan, Zhiqiang; Wang, Lei; Liu, He; Liu, Di; Li, Yan-Qiang; Zhang, Yao-Dong; Zhang, Hongxing; Ding, Hai-Lei; Cao, Jun-Li

    2017-09-01

    The authors previously reported that noncoding microRNA miR-219-5p is down-regulated in the spinal cord in a nociceptive state. The ventral tegmental area also plays critical roles in modulating nociception, although the underlying mechanism remains unknown. The authors hypothesized that miR-219-5p in the ventral tegmental area also may modulate nociception. The authors studied the bidirectional regulatory role of ventral tegmental area miR-219-5p in a rat complete Freund's adjuvant model of inflammatory nociception by measuring paw withdrawal latencies. Using molecular biology technologies, the authors measured the effects of astroglial coiled-coil and C2 domain containing 1A/nuclear factor κB cascade and dopamine neuron activity on the down-regulation of ventral tegmental area miR-219-5p-induced nociceptive responses. MiR-219-5p expression in the ventral tegmental area was reduced in rats with thermal hyperalgesia. Viral overexpression of ventral tegmental area miR-219-5p attenuated complete Freund's adjuvant-induced nociception from 7 days after complete Freund's adjuvant injection (paw withdrawal latencies: 6.09 ± 0.83 s vs. 3.96 ± 0.76 s; n = 6/group). Down-regulation of ventral tegmental area miR-219-5p in naïve rats was sufficient to induce thermal hyperalgesia from 7 days after lentivirus injection (paw withdrawal latencies: 7.09 ± 1.54 s vs. 11.75 ± 2.15 s; n = 8/group), which was accompanied by increased glial fibrillary acidic protein (fold change: 2.81 ± 0.38; n = 3/group) and reversed by intraventral tegmental area injection of the astroglial inhibitor fluorocitrate. The nociceptive responses induced by astroglial miR-219-5p down-regulation were inhibited by interfering with astroglial coiled-coil and C2 domain containing 1A/nuclear factor-κB signaling. Finally, pharmacologic inhibition of ventral tegmental area dopamine neurons alleviated this hyperalgesia. Down-regulation of astroglial miR-219-5p in ventral

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

    OpenAIRE

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

    2017-01-01

    A novel PI3Kδ inhibitor TGR-1202 synergizes with proteasome inhibitor carfilzomib by silencing c-Myc in preclinical models of lymphoma.The unique activity of TGR-1202 as a single agent and in combination with carfilzomib is driven by an unexpected activity targeting CK1ε.

  16. Gene therapy of c-myc suppressor FUSE-binding protein-interacting repressor by Sendai virus delivery prevents tracheal stenosis.

    Directory of Open Access Journals (Sweden)

    Daisuke Mizokami

    Full Text Available Acquired tracheal stenosis remains a challenging problem for otolaryngologists. The objective of this study was to determine whether the Sendai virus (SeV-mediated c-myc suppressor, a far upstream element (FUSE-binding protein (FBP-interacting repressor (FIR, modulates wound healing of the airway mucosa, and whether it prevents tracheal stenosis in an animal model of induced mucosal injury. A fusion gene-deleted, non-transmissible SeV vector encoding FIR (FIR-SeV/ΔF was prepared. Rats with scraped airway mucosae were administered FIR-SeV/ΔF through the tracheostoma. The pathological changes in the airway mucosa and in the tracheal lumen were assessed five days after scraping. Untreated animals showed hyperplasia of the airway epithelium and a thickened submucosal layer with extensive fibrosis, angiogenesis, and collagen deposition causing lumen stenosis. By contrast, the administration of FIR-SeV/ΔF decreased the degree of tracheal stenosis (P < 0.05 and improved the survival rate (P < 0.05. Immunohistochemical staining showed that c-Myc expression was downregulated in the tracheal basal cells of the FIR-SeV/ΔF-treated animals, suggesting that c-myc was suppressed by FIR-SeV/ΔF in the regenerating airway epithelium of the injured tracheal mucosa. The airway-targeted gene therapy of the c-myc suppressor FIR, using a recombinant SeV vector, prevented tracheal stenosis in a rat model of airway mucosal injury.

  17. Simultaneous detection of human papillomavirus integration and c-MYC gene amplification in cervical lesions: an emerging marker for the risk to progression.

    Science.gov (United States)

    Gimenes, Fabrícia; Souza, Raquel Pantarotto; de Abreu, André Luelsdorf Pimenta; Pereira, Monalisa Wolski; Consolaro, Marcia Edilaine Lopes; da Silva, Vânia Ramos Sela

    2016-04-01

    The persistence of high-risk oncogenic human papillomavirus (HR-HPV) infection and its integration into the host genome are key steps in the induction of malignant alterations. c-MYC chromosome region is a frequent localization for HPV insertion that has been observed in chromosome band 8q24 by fluorescence in situ hybridization (FISH). We report the HPV viral integration and amplification patterns of the c-MYC gene in cytological smears with FISH as a potential biomarker for the progression of squamous intraepithelial lesions (SIL). HPV detection and genotyping by polymerase chain reaction (PCR) and FISH analysis by "Vysis Cervical FISH Probe" kit (ABBOTT Molecular Inc.) were performed in 37 cervical samples including 8 NILM, 7 ASC-US, 7 LSIL, 3 ASC-H, 7 HSIL and 5 SCC. The results show concordance between FISH and PCR techniques for HPV detection. The majority of the samples contained HR-HPV, the majority being -16 and -18 genotypes. HPV integration as determined by FISH was most frequent in high-risk lesions. The c-MYC gene amplification was found only in HPV-positive samples and was detected primarily in high-risk lesions and in cells with an integrated form of HPV. HPV integration and c-MYC gene amplification detected by FISH could be an important biomarker for use in clinical practice to determine SIL with a risk of progression.

  18. Analyzing the Effect of c-myc Oncogene and Matrix Mettalloproteinase-2 Enzyme Ekspression on Metastasis and Prognosis of Malignant Melanoma

    Directory of Open Access Journals (Sweden)

    Abdulcebbar Siyer

    2016-09-01

    Full Text Available Objectives: The aim of this study is to measure the effect of c-myc oncogene and matrix metalloproteinase-2 enzyme expression on metastasis and prognosis of malignant melanoma. At the end of this study, we hope to get information about the prognosis of melanoma, to be helpful for choosing the treatment strategy. Methods: Sixty-three patients treated in our hospital during 2006-2015 were included in this study. All clinical and histological parameters were collected from each patient’s records and survival rate is assessed. Forty-seven suitable tumor specimens were assessed by immunohistochemical stains and analyzed for the c-myc and MMP-2 positivity. All results were evaluated statistically for the effect on melanoma metastasis and survival rate. Results: C-myc positivity and MMP-2 positivity decreases the survival rate of melanoma. MMP-2 positivity increases the risk of death four more times. Conclusions: So this study confirms that we can evaluate c-myc and MMP-2 as a prognostic factor.

  19. Effect of Neem Leaf Extract (Azadirachta indica) on c-Myc Oncogene Expression in 4T1 Breast Cancer Cells of BALB/c Mice.

    Science.gov (United States)

    Othman, Fauziah; Motalleb, Gholamreza; Lam Tsuey Peng, Sally; Rahmat, Asmah; Basri, Rusliza; Pei Pei, Chong

    2012-01-01

    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. 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. The C500 group showed significant (p<0.05) suppression of c-Myc oncogene expression compared to the CC group. c-Myc was found to be down regulated under the effect of 500 mg/kg ethanolic neem leaf extract.

  20. Microwave-assisted synthesis of ruthenium(II) complexes with alkynes as potential inhibitor by selectively recognizing c-myc G-quadruplex DNA.

    Science.gov (United States)

    Zhang, Shuangyan; Wu, Qiong; Zhang, Hao; Wang, Qi; Wang, Xicheng; Mei, Wenjie; Wu, Xiaohui; Zheng, Wenjie

    2017-11-01

    Herein, two polypyridyl ruthenium(II) complexes with alkynes, [Ru(bpy)2L](ClO4)2 (L=p-TEPIP (1) and p-BEPIP (2); bpy=2,2'-bipyridine; p-TEPIP=2-(4-trimethylsilylpropargyl)-1H-imidazo[4,5f][1,10]phenanthroline; p-BEPIP=2-(4-phenyacetylenephenyl)-1H-imidazo[4,5f][1,10]phenanthroline) have been successfully achieved in yields of 32%-89% by a Sonogashira coupling reaction under microwave irradiation. We studied these complexes as potential stabilizers of c-myc G-quadruplex DNA. Observations revealed that both complexes could selectively bind to and stabilize c-myc G-quadruplex DNA with a constant of approximately 1.61±0.78 and 9.47±4.20×10(3)M(-1), respectively, as determined from ITC (isothermal ttitration calorimetry) experiments, FRET (fluorescence resonance energy ttransfer) assay and competitive FRET assay. Moreover, the melting point (Tm) of the c-myc G-quadruplex DNA increased in the presence of 1 and 2 ([Ru]=0.2μM) by approximately 9 and 19.9°C, respectively. It is noteworthy that the conformation of the c-myc G-quadruplex DNA appeared to change when titrated with 1 and 2, which was accompanied by a negative-induced CD (circular dichroism) signal that appeared at a wavelength of 295nm. Furthermore, the conformational change in c-myc G-quadruplex DNA induced by 1 and 2have also been confirmed by TEM (transmission electron microscopy) and AFM (atomic force microscopy). Consequently, the replication of c-myc DNA was blocked by 1 and 2, and especially by 2, as verified by PCR (polymerase chain reaction) -stop assay and Western-blot assay. Thus, these ruthenium(II) complexes can be developed as potential inhibitors in chemotherapy through their binding and stabilization of c-myc G-quadruplex DNA. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Structure-based design of platinum(II) complexes as c-myc oncogene down-regulators and luminescent probes for G-quadruplex DNA.

    Science.gov (United States)

    Wang, Ping; Leung, Chung-Hang; Ma, Dik-Lung; Yan, Siu-Cheong; Che, Chi-Ming

    2010-06-18

    A series of platinum(II) complexes with tridentate ligands was synthesized and their interactions with G-quadruplex DNA within the c-myc gene promoter were evaluated. Complex 1, which has a flat planar 2,6-bis(benzimidazol-2-yl)pyridine (bzimpy) scaffold, was found to stabilize the c-myc G-quadruplex structure in a cell-free system. An in silico G-quadruplex DNA model has been constructed for structure-based virtual screening to develop new Pt(II)-based complexes with superior inhibitory activities. By using complex 1 as the initial structure for hit-to-lead optimization, bzimpy and related 2,6-bis(pyrazol-3-yl)pyridine (dPzPy) scaffolds containing amine side-chains emerge as the top candidates. Six of the top-scoring complexes were synthesized and their interactions with c-myc G-quadruplex DNA have been investigated. The results revealed that all of the complexes have the ability to stabilize the c-myc G-quadruplex. Complex 3 a ([Pt(II)L2R](+); L2=2,6-bis[1-(3-piperidinepropyl)-1H-enzo[d]imidazol-2-yl]pyridine, R=Cl) displayed the strongest inhibition in a cell-free system (IC(50)=2.2 microM) and was 3.3-fold more potent than that of 1. Complexes 3 a and 4 a ([Pt(II)L3R](+); L3=2,6-bis[1-(3-morpholinopropyl)-1H-pyrazol-3-yl]pyridine, R=Cl) were found to effectively inhibit c-myc gene expression in human hepatocarcinoma cells with IC(50) values of approximately 17 microM, whereas initial hit 1 displayed no significant effect on gene expression at concentrations up to 50 microM. Complexes 3 a and 4 a have a strong preference for G-quadruplex DNA over duplex DNA, as revealed by competition dialysis experiments and absorption titration; 3 a and 4 a bind G-quadruplex DNA with binding constants (K) of approximately 10(6)-10(7) dm(3) mol(-1), which are at least an order of magnitude higher than the K values for duplex DNA. NMR spectroscopic titration experiments and molecular modeling showed that 4 a binds c-myc G-quadruplex DNA through an external end-stacking mode at

  2. Stabilization of G-quadruplex DNA with platinum(II) Schiff base complexes: luminescent probe and down-regulation of c-myc oncogene expression.

    Science.gov (United States)

    Wu, Peng; Ma, Dik-Lung; Leung, Chung-Hang; Yan, Siu-Cheong; Zhu, Nianyong; Abagyan, R; Che, Chi-Ming

    2009-12-07

    The interactions of a series of platinum(II) Schiff base complexes with c-myc G-quadruplex DNA were studied. Complex [PtL(1a)] (1 a; H(2)L(1a)=N,N'-bis(salicylidene)-4,5-methoxy-1,2-phenylenediamine) can moderately inhibit c-myc gene promoter activity in a cell-free system through stabilizing the G-quadruplex structure and can inhibit c-myc oncogene expression in cultured cells. The interaction between 1 a and G-quadruplex DNA has been examined by (1)H NMR spectroscopy. By using computer-aided structure-based drug design for hit-to-lead optimization, an in silico G-quadruplex DNA model has been constructed for docking-based virtual screening to develop new platinum(II) Schiff base complexes with improved inhibitory activities. Complex [PtL(3)] (3; H(2)L(3)=N,N'-bis{4-[1-(2-propylpiperidine)oxy]salicylidene}-4,5-methoxy-1,2-phenylenediamine) has been identified with a top score in the virtual screening. This complex was subsequently prepared and experimentally tested in vitro for its ability to stabilize or induce the formation of the c-myc G-quadruplex. The inhibitory activity of 3 (IC(50)=4.4 muM) is tenfold more than that of 1 a. The interaction between 1 a or 3 with c-myc G-quadruplex DNA has been examined by absorption titration, emission titration, molecular modeling, and NMR titration experiments, thus revealing that both 1 a and 3 bind c-myc G-quadruplex DNA through an external end-stacking mode at the 3' terminal face of the G-quadruplex. Such binding of G-quadruplex DNA with 3 is accompanied by up to an eightfold increase in the intensity of photoluminescence at lambda(max)=652 nm. Complex 3 also effectively down-regulated the expression of c-myc in human hepatocarcinoma cells.

  3. The Effect of Molecular Crowding on the Stability of Human c-MYC Promoter Sequence I-Motif at Neutral pH

    Directory of Open Access Journals (Sweden)

    Edwin A. Lewis

    2013-10-01

    Full Text Available We have previously shown that c-MYC promoter sequences can form stable i-motifs in acidic solution (pH 4.5–5.5. In terms of drug targeting, the question is whether c-MYC promoter sequence i-motifs will exist in the nucleus at neutral pH. In this work, we have investigated the stability of a mutant c-MYC i-motif in solutions containing a molecular crowding agent. The crowded nuclear environment was modeled by the addition of up to 40% w/w polyethylene glycols having molecular weights up to 12,000 g/mol. CD and DSC were used to establish the presence and stability of c-MYC i-motifs in buffer solutions over the pH range 4 to 7. We have shown that the c-MYC i-motif can exist as a stable structure at pH values as high as 6.7 in crowded solutions. Generic dielectric constant effects, e.g., a shift in the pKa of cytosine by more than 2 units (e.g., 4.8 to 7.0, or the formation of non-specific PEG/DNA complexes appear to contribute insignificantly to i-motif stabilization. Molecular crowding, largely an excluded volume effect of added PEG, having a molecular weight in excess of 1,000 g/mol, appears to be responsible for stabilizing the more compact i-motif over the random coil at higher pH values.

  4. PIK3CD promoted proliferation in diffuse large B cell lymphoma through upregulation of c-myc.

    Science.gov (United States)

    Cui, Wenli; Zheng, Shutao; Li, Xinxia; Ma, Yuqing; Sang, Wei; Liu, Ming; Zhang, Wei; Zhou, Xiaoyan

    2016-09-01

    Despite PIK3CD has been extensively reported in cancers, however, little evidence has been available regarding its role in the setting of diffuse large B cell lymphoma (DLBCL). In the present study, to investigate the role of PIK3CD in DLBCL, relevant experiments were carried out on both in vivo clinical tissue level and in vitro cell line level. Prognostic and clinicopathological significance were analyzed after immunohistochemical assay of PIK3CD expression on DLBCL tissue microarray. MTT assay and flow cytometry were employed to evaluate the proliferative variation, cell cycle, and apoptosis. Athymic nude mice xenografted with DLBCL cell line were employed to confirm the role of PIK3CD. It was found that there was a significant difference between expression of PIK3CD and international prognosis index (IPI), performance state (PS), and inferior overall prognosis. Furthermore, PIK3CD can promote proliferation and prevent apoptosis in DLBCL cells in vitro through upregulation of c-myc and p-AKT and in contrast downregulation of p21 and p27. In nude mice model, knock-down of PIK3CD was shown to be able to suppress the proliferation of DLBCL but not significantly compared with control group. Taken together, our study showed that PIK3CD can promote proliferation of DLBCL cells both in vitro and in vivo, suggesting that PIK3CD could be druggable in the therapy of DLBCL.

  5. HER2, TOP2A, CCND1, EGFR and C-MYC oncogene amplification in colorectal cancer.

    Science.gov (United States)

    Al-Kuraya, Khawla; Novotny, Hedvika; Bavi, Prashant; Siraj, Abdul K; Uddin, Shahab; Ezzat, Adnan; Sanea, Nasser Al; Al-Dayel, Fouad; Al-Mana, Hadeel; Sheikh, Salwa S; Mirlacher, Martina; Tapia, Coya; Simon, Ronald; Sauter, Guido; Terracciano, Luigi; Tornillo, Luigi

    2007-07-01

    Recent studies had suggested substantial molecular differences between tumours from different ethnic groups. In this study, the molecular differences between the incidences of colorectal carcinoma in Saudi and Swiss populations are investigated. 518 cases of colon cancer tumours (114 from Saudi Arabia and 404 from Switzerland) were analysed in a tissue microarray format. Fluorescence in situ hybridisation (FISH) was used to estimate frequencies of copy number changes of known oncogenes, including HER2, TOPO2A, CCND1, EGFR and C-MYC. Using FISH, amplifications were mostly low level (gene-to-centromere ratio 2 to 4), which is in contrast with other tumour types with more frequent gene amplifications. The amplifications were particularly frequent for MYC (Saudi 9% and Swiss 14.2%) but unrelated to clinical outcome and pathological information. Remarkably, there were four tumours exhibiting classic high-level gene amplification for HER2 (Swiss 1.3%), a pattern often accompanied by response to trastuzumab (Herceptin) in breast cancer. Occasional high-level amplifications were also observed for CCND1 (Saudi 1/106, 0.9%; Swiss 2/373, 0.5%) and EGFR (Swiss 2/355; 0.6%). Rare high-level amplifications of therapeutic target genes were found in patients with colon cancer. Although no molecular differences were found between incidences of colon cancer cases in Swiss and Saudi populations, these observations emphasise the urgent need for clinical studies investigating the effect of targeted therapies.

  6. Quinolino-benzo-[5, 6]-dihydroisoquindolium compounds derived from berberine: a new class of highly selective ligands for G-quadruplex DNA in c-myc oncogene.

    Science.gov (United States)

    Ma, Yan; Ou, Tian-Miao; Tan, Jia-Heng; Hou, Jin-Qiang; Huang, Shi-Liang; Gu, Lian-Quan; Huang, Zhi-Shu

    2011-05-01

    A series of quinolino-benzo-[5, 6]-dihydroisoquindolium compounds (3a, 3f, 3g, and 3j) derived from alkaloid berberine were designed and synthesized as novel G-quadruplex ligands. Subsequent biophysical and biochemical evaluation demonstrated that the addition of pyridine ring and amino group into berberine improved the binding ability and selectivity towards G-quadruplex DNA in comparison with the previously reported 9-N-substituted berberine derivatives. Furthermore, qRT-PCR assay showed compound 3j led the down-regulation of c-myc gene transcription in leukemia cell line HL60, while little effect on normal cell line ECV-304, which was consistent with the behavior of an effective G-quadruplex ligand targeting c-myc oncogene. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

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

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    Susi Endrini

    2015-01-01

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

  8. Diminished WNT → β-catenin → c-MYC signaling is a barrier for malignant progression of BRAFV600E-induced lung tumors

    Science.gov (United States)

    Juan, Joseph; Muraguchi, Teruyuki; Iezza, Gioia; Sears, Rosalie C.; McMahon, Martin

    2014-01-01

    Oncogene-induced senescence (OIS) is proposed as a cellular defense mechanism that restrains malignant progression of oncogene-expressing, initiated tumor cells. Consistent with this, expression of BRAFV600E in the mouse lung epithelium elicits benign tumors that fail to progress to cancer due to an apparent senescence-like proliferative arrest. Here we demonstrate that nuclear β-catenin → c-MYC signaling is essential for early stage proliferation of BRAFV600E-induced lung tumors and is inactivated in the subsequent senescence-like state. Furthermore, either β-catenin silencing or pharmacological blockade of Porcupine, an acyl-transferase essential for WNT ligand secretion and activity, significantly inhibited BRAFV600E-initiated lung tumorigenesis. Conversely, sustained activity of β-catenin or c-MYC significantly enhanced BRAFV600E-induced lung tumorigenesis and rescued the anti-tumor effects of Porcupine blockade. These data indicate that early stage BRAFV600E-induced lung tumors are WNT-dependent and suggest that inactivation of WNT → β-catenin → c-MYC signaling is a trigger for the senescence-like proliferative arrest that constrains the expansion and malignant progression of BRAFV600E-initiated lung tumors. Moreover, these data further suggest that the trigger for OIS in initiated BRAFV600E-expressing lung tumor cells is not simply a surfeit of signals from oncogenic BRAF but an insufficiency of WNT → β-catenin → c-MYC signaling. These data have implications for understanding how genetic abnormalities cooperate to initiate and promote lung carcinogenesis. PMID:24589553

  9. Equol, an Isoflavone Metabolite, Regulates Cancer Cell Viability and Protein Synthesis Initiation via c-Myc and eIF4G*

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    de la Parra, Columba; Borrero-Garcia, Luis D.; Cruz-Collazo, Ailed; Schneider, Robert J.; Dharmawardhane, Suranganie

    2015-01-01

    Epidemiological studies implicate dietary soy isoflavones as breast cancer preventives, especially due to their anti-estrogenic properties. However, soy isoflavones may also have a role in promoting breast cancer, which has yet to be clarified. We previously reported that equol, a metabolite of the soy isoflavone daidzein, may advance breast cancer potential via up-regulation of the eukaryotic initiation factor 4GI (eIF4GI). In estrogen receptor negative (ER−) metastatic breast cancer cells, equol induced elevated levels of eIF4G, which were associated with increased cell viability and the selective translation of mRNAs that use non-canonical means of initiation, including internal ribosome entry site (IRES), ribosome shunting, and eIF4G enhancers. These mRNAs typically code for oncogenic, survival, and cell stress molecules. Among those mRNAs translationally increased by equol was the oncogene and eIF4G enhancer, c-Myc. Here we report that siRNA-mediated knockdown of c-Myc abrogates the increase in cancer cell viability and mammosphere formation by equol, and results in a significant down-regulation of eIF4GI (the major eIF4G isoform), as well as reduces levels of some, but not all, proteins encoded by mRNAs that are translationally stimulated by equol treatment. Knockdown of eIF4GI also markedly reduces an equol-mediated increase in IRES-dependent mRNA translation and the expression of specific oncogenic proteins. However, eIF4GI knockdown did not reciprocally affect c-Myc levels or cell viability. This study therefore implicates c-Myc as a potential regulator of the cancer-promoting effects of equol via up-regulation of eIF4GI and selective initiation of translation on mRNAs that utilize non-canonical initiation, including certain oncogenes. PMID:25593313

  10. Effect of teicoplanin on the expression of c-myc and c-fos proto-oncogenes in MCF-7 breast cancer cell line

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    Saeideh Ashouri

    2016-01-01

    Conclusion: it could be concluded that although teicoplanin is considered as an enhancing cell growth and proliferation, but probably its effect is not through MAP kinase signaling pathway or perhaps even has inhibitory effect on the expression of some genes such as c-myc and c-fos in this pathway. Hence, the mechanism of action of teicoplanin for increasing cell propagation, through cell signaling pathways or chromosomal abnormalities, remains unclear, and further studies should be conducted.

  11. 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

    al. 1999, Di Cristofano & Pandolfi 2000). In a cells, and that co-transfection with another oncogene or myc-CAT ( chloramphenicol acetyl transferase...sexes of as well, with a 50% incidence at about 7 months, slightly animals suggest that the strong synergism between the two earlier than that in MMTV...tgfci nor c-myc been reported to be associated with a reduced survival in alone is a sufficient carcinogenic factor, their synergism is some studies

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

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    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.

  13. Mutant p53 Gains Its Function via c-Myc Activation upon CDK4 Phosphorylation at Serine 249 and Consequent PIN1 Binding.

    Science.gov (United States)

    Liao, Peng; Zeng, Shelya X; Zhou, Xiang; Chen, Tianjian; Zhou, Fen; Cao, Bo; Jung, Ji Hoon; Del Sal, Giannino; Luo, Shiwen; Lu, Hua

    2017-11-23

    TP53 missense mutations significantly influence the development and progression of various human cancers via their gain of new functions (GOF) through different mechanisms. Here we report a unique mechanism underlying the GOF of p53-R249S (p53-RS), a p53 mutant frequently detected in human hepatocellular carcinoma (HCC) that is highly related to hepatitis B infection and aflatoxin B1. A CDK inhibitor blocks p53-RS's nuclear translocation in HCC, whereas CDK4 interacts with p53-RS in the G1/S phase of the cells, phosphorylates it, and enhances its nuclear localization. This is coupled with binding of a peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (PIN1) to p53-RS, but not the p53 form with mutations of four serines/threonines previously shown to be crucial for PIN1 binding. As a result, p53-RS interacts with c-Myc and enhances c-Myc-dependent rDNA transcription key for ribosomal biogenesis. These results unveil a CDK4-PIN1-p53-RS-c-Myc pathway as a novel mechanism for the GOF of p53-RS in HCC. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Ketogenic HMGCS2 Is a c-Myc target gene expressed in differentiated cells of human colonic epithelium and down-regulated in colon cancer.

    Science.gov (United States)

    Camarero, Nuria; Mascaró, Cristina; Mayordomo, Cristina; Vilardell, Felip; Haro, Diego; Marrero, Pedro F

    2006-09-01

    HMGCS2, the gene that regulates ketone body production, is expressed in liver and several extrahepatic tissues, such as the colon. In CaCo-2 colonic epithelial cells, the expression of this gene increases with cell differentiation. Accordingly, immunohistochemistry with specific antibodies shows that HMGCS2 is expressed mainly in differentiated cells of human colonic epithelium. Here, we used a chromatin immunoprecipitation assay to study the molecular mechanism responsible for this expression pattern. The assay revealed that HMGCS2 is a direct target of c-Myc, which represses HMGCS2 transcriptional activity. c-Myc transrepression is mediated by blockade of the transactivating activity of Miz-1, which occurs mainly through a Sp1-binding site in the proximal promoter of the gene. Accordingly, the expression of human HMGCS2 is down-regulated in 90% of Myc-dependent colon and rectum tumors. HMGCS2 protein expression is down-regulated preferentially in moderately and poorly differentiated carcinomas. In addition, it is also down-regulated in 80% of small intestine Myc-independent tumors. Based on these findings, we propose that ketogenesis is an undesirable metabolic characteristic of the proliferating cell, which is down-regulated through c-Myc-mediated repression of the key metabolic gene HMGCS2.

  15. Tumor suppressor PDCD4 modulates miR-184-mediated direct suppression of C-MYC and BCL2 blocking cell growth and survival in nasopharyngeal carcinoma.

    Science.gov (United States)

    Zhen, Yan; Liu, Zhen; Yang, Huiling; Yu, Xiaoli; Wu, Qiangyun; Hua, Shengni; Long, Xiaobin; Jiang, Qingping; Song, Ye; Cheng, Chao; Wang, Hao; Zhao, Menyang; Fu, Qiaofen; Lyu, Xiaoming; Chen, Yiyu; Fan, Yue; Liu, Yan; Li, Xin; Fang, Weiyi

    2013-10-24

    Programmed cell death 4 (PDCD4), a novel tumor suppressor, inhibits cell proliferation, migration and invasion as well as promotes cell apoptosis in tumors. However, the molecular mechanism of its tumor-suppressive function remains largely unknown in tumors including nasopharyngeal carcinoma (NPC). In this study, downregulated PDCD4 expression was significantly associated with the status of NPC progression and poor prognosis. PDCD4 markedly suppressed the ability of cell proliferation and cell survival by modulating C-MYC-controlled cell cycle and BCL-2-mediated mitochondrion apoptosis resistance signals, and oncogenic transcription factor C-JUN in NPC. Furthermore, miR-184, a tumor-suppressive miRNA modulated by PDCD4 directly targeting BCL2 and C-MYC, participated in PDCD4-mediated suppression of cell proliferation and survival in NPC. Further, we found that PDCD4 decreased the binding of C-Jun to the AP-1 element on the miR-184 promoter regions by PI3K/AKT/JNK/C-Jun pathway and stimulated miR-184 expression. In clinical fresh specimens, reduced PDCD4 mRNA level was positively correlated with miR-184 expression in NPC. Our studies are the first to demonstrate that PDCD4 as tumor suppressor regulated miR-184-mediated direct targeting of BCL2 and C-MYC via PI3K/AKT and JNK/C-Jun pathway attenuating cell proliferation and survival in NPC.

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

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    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.

  17. K-Ras and B-Raf oncogenes inhibit colon epithelial polarity establishment through up-regulation of c-myc.

    Science.gov (United States)

    Magudia, Kirti; Lahoz, Aurelia; Hall, Alan

    2012-07-23

    KRAS, BRAF, and PI3KCA are the most frequently mutated oncogenes in human colon cancer. To explore their effects on morphogenesis, we used the colon cancer-derived cell line Caco-2. When seeded in extracellular matrix, individual cells proliferate and generate hollow, polarized cysts. The expression of oncogenic phosphatidylinositol 3-kinase (PI3KCA H1047R) in Caco-2 has no effect, but K-Ras V12 or B-Raf V600E disrupts polarity and tight junctions and promotes hyperproliferation, resulting in large, filled structures. Inhibition of mitogen-activated protein/extracellular signal-regulated kinase (ERK) kinase blocks the disruption of morphology, as well as the increased levels of c-myc protein induced by K-Ras V12 and B-Raf V600E. Apical polarity is already established after the first cell division (two-cell stage) in Caco-2 three-dimensional cultures. This is disrupted by expression of K-Ras V12 or B-Raf V600E but can be rescued by ribonucleic acid interference-mediated depletion of c-myc. We conclude that ERK-mediated up-regulation of c-myc by K-Ras or B-Raf oncogenes disrupts the establishment of apical/basolateral polarity in colon epithelial cells independently of its effect on proliferation.

  18. Keratinocyte transcriptional regulation of the human c-Myc promoter occurs via a novel Lef/Tcf binding element distinct from neoplastic cells.

    Science.gov (United States)

    Kolly, Carine; Zakher, Antony; Strauss, Christian; Suter, Maja M; Müller, Eliane J

    2007-05-15

    The proto-oncogene c-Myc is involved in early neoplastic transformations. Two consensus Lef/Tcf binding elements (TBE) were found to be prerequisite for transcriptional transactivation by the armadillo proteins beta-catenin and plakoglobin (PG) together with Tcf4 in human neoplastic cells. In epidermal keratinocytes, c-Myc was reported to be repressed by Lef-1 and PG. Using reporter gene assays, here we demonstrate that deletion of the two consensus TBE fails to abrogate transcriptional regulation by Lef-1/PG in wildtype and beta-catenin-/- keratinocytes, while it reduces transcription in pre-neoplastic PG-/- keratinocytes. We identified a TBE sequence variant downstream of the major transcriptional initiation site that binds Lef-1 in vitro and in vivo, and its mutation compromised transcriptional regulation by Lef-1/PG. Collectively, this study demonstrates that the two consensus TBE's reported in neoplastic cells are dispensable for c-Myc regulation in normal keratinocytes, which instead use a novel TBE sequence variant. This unprecedented finding may have important implications for armadillo target genes involved in carcinogenesis.

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

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    Hiroshi Kitani

    2014-01-01

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

  20. Transgenic rabbits with lymphocytic leukemia induced by the c-myc oncogene fused with the immunoglobulin heavy chain enhancer.

    Science.gov (United States)

    Knight, K L; Spieker-Polet, H; Kazdin, D S; Oi, V T

    1988-01-01

    Transgenic rabbits with the rabbit c-myc oncogene fused with the rabbit immunoglobulin heavy chain enhancer region (E mu) DNA were developed by microinjecting pronuclei of single cell zygotes with the gene construct and implanting the microinjected eggs into pseudopregnant females. At age 17-20 days, 3 of 21 offspring born to seven females were found to have peripheral blood leukocyte counts of greater than 100,000 per mm3. Histology analyses showed extensive lymphocytic infiltration in the liver and kidney, indicating that these rabbits had a malignant lymphocytic leukemia. Genomic DNA analyses of thymus and peripheral blood lymphocytes revealed that the leukemic rabbits were transgenic and that both immunoglobulin heavy and kappa light chain genes were rearranged in the leukemic cells; thus, the leukemic cells are of B-cell lineage. One to four heavy and light chain gene rearrangements were observed, suggesting that the B-cell tumors were oligoclonal. Stable tissue culture cell lines from the bone marrow and peripheral blood of one of the transgenic rabbits have been developed. The development of B-cell leukemias in rabbits with the E mu-myc transgene contrasts with the development of B-cell lymphomas in mice carrying a similar transgene. The lymphomas in mice develop in adults and are monoclonal in origin. The leukemias in rabbits develop in juveniles, less than 3 weeks after birth, and appear oligoclonal in origin. The leukemias seem to develop in rabbit at a specific stage of development, and we suggest that a normal developmental signal may be involved in the oncogenesis. Images PMID:2834733

  1. Thiopurine methyltransferase predicts the extent of cytotoxicty and DNA damage in astroglial cells after thioguanine exposure.

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    Amira Hosni-Ahmed

    Full Text Available Thiopurine methyltransferase (Tpmt is the primary enzyme responsible for deactivating thiopurine drugs. Thiopurine drugs (i.e., thioguanine [TG], mercaptopurine, azathioprine are commonly used for the treatment of cancer, organ transplant, and autoimmune disorders. Chronic thiopurine therapy has been linked to the development of brain cancer (most commonly astrocytomas, and Tpmt status has been associated with this risk. Therefore, we investigated whether the level of Tpmt protein activity could predict TG-associated cytotoxicity and DNA damage in astrocytic cells. We found that TG induced cytotoxicity in a dose-dependent manner in Tpmt(+/+, Tpmt(+/- and Tpmt(-/- primary mouse astrocytes and that a low Tpmt phenotype predicted significantly higher sensitivity to TG than did a high Tpmt phenotype. We also found that TG exposure induced significantly more DNA damage in the form of single strand breaks (SSBs and double strand breaks (DSBs in primary astrocytes with low Tpmt versus high Tpmt. More interestingly, we found that Tpmt(+/- astrocytes had the highest degree of cytotoxicity and genotoxicity (i.e., IC(50, SSBs and DSBs after TG exposure. We then used human glioma cell lines as model astroglial cells to represent high (T98 and low (A172 Tpmt expressers and found that A172 had the highest degree of cytoxicity and SSBs after TG exposure. When we over-expressed Tpmt in the A172 cell line, we found that TG IC(50 was significantly higher and SSB's were significantly lower as compared to mock transfected cells. This study shows that low Tpmt can lead to greater sensitivity to thiopurine therapy in astroglial cells. When Tpmt deactivation at the germ-line is considered, this study also suggests that heterozygosity may be subject to the greatest genotoxic effects of thiopurine therapy.

  2. Feedback circuitry via let-7c between lncRNA CCAT1 and c-Myc is involved in cigarette smoke extract-induced malignant transformation of HBE cells.

    Science.gov (United States)

    Lu, Lu; Qi, Hong; Luo, Fei; Xu, Hui; Ling, Min; Qin, Yu; Yang, Ping; Liu, Xinlu; Yang, Qianlei; Xue, Junchao; Chen, Chao; Lu, Jiachun; Xiang, Quanyong; Liu, Qizhan; Bian, Qian

    2017-03-21

    Cigarette smoking is a primary risk factor for the development of lung cancer, which is regarded as the leading cause of cancer-related deaths. The process of malignant transformation of cells, however, is complex and elusive. The present study investigated the roles of an lncRNA, CCAT1, and a transcriptional factor, c-Myc, in human bronchial epithelial (HBE) cell transformation induced by cigarette smoke extract. With acute and chronic treatment of HBE cells, cigarette smoke extract induced increases of CCAT1 and c-Myc levels and decreases of levels of let-7c, a microRNA. Down-regulation of c-Myc reduced the degree of malignancy and the invasion/migration capacity of HBE cells transformed by cigarette smoke extract. ChIP assays established that c-Myc, increased by cigarette smoke extract, binds to the promoter of CCAT1, activating its transcription. Further, let-7c suppressed the expression of c-Myc through binding to its 3'-UTR. In turn, CCAT1 promoted the accumulation of c-Myc through binding to let-7c and decreasing free let-7c, which influenced the neoplastic capacity of HBE cells transformed by cigarette smoke extract. These results indicate that a positive feedback loop ensures expression of cigarette smoke extract-induced CCAT1 and c-Myc via let-7c, which is involved in cigarette smoke extract-induced malignant transformation of HBE cells. Thus, the present research establishes a new mechanism for the reciprocal regulation between CCAT1 and c-Myc and provides an understanding of cigarette smoke extract-induced lung carcinogenesis.

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

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    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

  4. MicroRNA-184 Deregulated by the MicroRNA-21 Promotes Tumor Malignancy and Poor Outcomes in Non-small Cell Lung Cancer via Targeting CDC25A and c-Myc.

    Science.gov (United States)

    Lin, Tsang-Chi; Lin, Po-Lin; Cheng, Ya-Wen; Wu, Tzu-Chin; Chou, Ming-Chih; Chen, Chih-Yi; Lee, Huei

    2015-12-01

    MicroRNA (miR)-184 has been reported to have a dual role in human cancers. However, the role of miR-184 in non-small cell lung cancer (NSCLC) remains unclear. Wild-type or mutant CDC25A promoters were constructed by PCR and site-directed mutagenesis to verify whether miR-184 could inhibit CDC25A expression at post-transcription level. Boyden chamber assay was used to assess whether miR-184 could modulate cell invasiveness via targeting CDC25A and c-Myc. We utilized 124 tumors from NSCLC patients to determine miR-184, miR-21, PDCD4 mRNA, c-Myc mRNA, and CDC25A mRNA expression levels by means of real-time PCR analysis. The prognostic value of CDC25A, c-Myc, and miR-184 on overall survival (OS) and relapse-free survival (RFS) was evaluated by Kaplan-Meier and Cox regression analysis. MiR-184 suppressed CDC25A expression by enhancing the instability of its mRNA as a result of miR-184 binding to its coding region. An increase in CDC25A expression by means of a reduction in miR-184 promotes cell invasiveness. Moreover, a concomitant increase in CDC25A and c-Myc expression as a result of decreased miR-184 via the miR-21-mediated PDCD4 reduction is responsible for cell invasiveness. Among patients, miR-184 expression in lung tumors was found to correlate negatively with CDC25A mRNA, c-Myc mRNA, and miR-21 expression, but was positively related to PDCD4 mRNA expression. High-miR-184, High-CDC25A, or high-c-Myc mRNA tumors exhibited shorter OS and RFS periods than their counterparts. The worst OS and RFS were observed in low-miR-184/high-CDC25A/high-c-Myc tumors, followed by low-miR-184 /high-CDC25A, low-miR-184/high-c-Myc, high-c-Myc, and high-CDC25A tumors. MiR-184 as a tumor suppressor miR inhibits cell proliferation and invasion capability via targeting CDC25A and c-Myc. Low miR-184 level may predict worse prognosis in NSCLC patients.

  5. AKT (v-akt murine thymoma viral oncogene homolog 1) and N-Ras (neuroblastoma ras viral oncogene homolog) coactivation in the mouse liver promotes rapid carcinogenesis by way of mTOR (mammalian target of rapamycin complex 1), FOXM1 (forkhead box M1)/SKP2, and c-Myc pathways.

    Science.gov (United States)

    Ho, Coral; Wang, Chunmei; Mattu, Sandra; Destefanis, Giulia; Ladu, Sara; Delogu, Salvatore; Armbruster, Julia; Fan, Lingling; Lee, Susie A; Jiang, Lijie; Dombrowski, Frank; Evert, Matthias; Chen, Xin; Calvisi, Diego F

    2012-03-01

    Activation of v-akt murine thymoma viral oncogene homolog (AKT) and Ras pathways is often implicated in carcinogenesis. However, the oncogenic cooperation between these two cascades in relationship to hepatocellular carcinoma (HCC) development remains undetermined. To investigate this issue, we generated a mouse model characterized by combined overexpression of activated forms of AKT and neuroblastoma Ras viral oncogene homolog (N-Ras) protooncogenes in the liver by way of hydrodynamic gene transfer. The molecular mechanisms underlying crosstalk between AKT and N-Ras were assessed in the mouse model and further evaluated in human and murine HCC cell lines. We found that coexpression of AKT and N-Ras resulted in a dramatic acceleration of liver tumor development when compared with mice overexpressing AKT alone, whereas N-Ras alone did not lead to tumor formation. At the cellular level, concomitant up-regulation of AKT and N-Ras resulted in increased proliferation and microvascularization when compared with AKT-injected mice. Mechanistic studies suggested that accelerated hepatocarcinogenesis driven by AKT and N-Ras resulted from a strong activation of mammalian target of rapamycin complex 1 (mTORC1). Furthermore, elevated expression of FOXM1/SKP2 and c-Myc also contributed to rapid tumor growth in AKT/Ras mice, yet by way of mTORC1-independent mechanisms. The biological effects of coactivation of AKT and N-Ras were then recapitulated in vitro using HCC cell lines, which supports the functional significance of mTORC1, FOXM1/SKP2, and c-Myc signaling cascades in mediating AKT and N-Ras-induced liver tumor development. Our data demonstrate the in vivo crosstalk between the AKT and Ras pathways in promoting liver tumor development, and the pivotal role of mTORC1-dependent and independent pathways in mediating AKT and Ras induced hepatocarcinogenesis. Copyright © 2011 American Association for the Study of Liver Diseases.

  6. Increases in iPS Transcription Factor (Oct4, Sox2, c-Myc, and Klf4) Gene Expression after Modified Electroconvulsive Therapy.

    Science.gov (United States)

    Nishiguchi, Masaki; Kikuyama, Hiroki; Kanazawa, Tetsufumi; Tsutsumi, Atsushi; Kaneko, Takao; Uenishi, Hiroyuki; Kawabata, Yasuo; Kawashige, Seiya; Koh, Jun; Yoneda, Hiroshi

    2015-10-01

    Electroconvulsive therapy (ECT) is a reasonable option for intractable depression or schizophrenia, but a mechanism of action has not been established. One credible hypothesis is related to neural plasticity. Three genes (Oct4, Sox2, c-Myc) involved in the induction of induced pluripotent stem (iPS) cells are Wnt-target genes, which constitute a key gene group involved in neural plasticity through the TCF family. Klf4 is the other gene among Yamanaka's four transcription factors, and increases in its expression are induced by stimulation of the canonical Wnt pathway. We compared the peripheral blood gene expression of the four iPS genes (Oct4, Sox2, c-Myc, and Klf4) before and after modified ECT (specifically ECT with general anesthesia) of patients with intractable depression (n=6) or schizophrenia (n=6). Using Thymatron ten times the total bilateral electrical stimulation was evoked. Both assessments of the symptoms demonstrated significant improvement after mECT stimulation. Expression of all four genes was confirmed to increase after initial stimulation. The gene expression levels after treatment were significantly different from the initial gene expression in all twelve cases at the following treatment stages: at the 3rd mECT for Oct4; at the 6th and 10th mECT for Sox2; and at the 3rd, 6th and 10th mECT for c-Myc. These significant differences were not present after correction for multiple testing; however, our data have the potential to explain the molecular mechanisms of mECT from a unique perspective. Further studie should be conducted to clarify the pathophysiological involvement of iPS-inducing genes in ECT.

  7. The BET Bromodomain Inhibitor JQ1 Suppresses Chondrosarcoma Cell Growth via Regulation of YAP/p21/c-Myc Signaling.

    Science.gov (United States)

    Zhang, Huan-Tian; Gui, Tao; Sang, Yuan; Yang, Jie; Li, Yu-Hang; Liang, Gui-Hong; Li, Thomas; He, Qing-Yu; Zha, Zhen-Gang

    2017-08-01

    Chondrosarcoma, the second-most frequent primary bone malignancy, is generally more resistant to conventional chemotherapy and radiotherapy. Therefore, the development of an effective adjuvant therapy is necessary. Recently, targeting the epigenetic regulator such as bromodomain and extraterminal domain (BET) proteins has achieved great success. For instance, the bromodomain inhibitor JQ1 has been shown to inhibit the growth of several cancer cells both in vitro and in vivo. Herein, we demonstrated that JQ1 significantly inhibited chondrosarcoma cell growth and colony formation. JQ1 also induced marked G1-phase cell cycle arrest coincided with the up-regulation of p21WAF1/CIP1 , p27Kip1 , and Cyclin D1 expression, and the down-regulation of Cyclin E2 expression. Moreover, JQ1 induced the premature senescence of SW 1353 cells, and that prolong treatment of JQ1 caused cell apoptosis. Mechanistically, the JQ1-induced cell growth inhibition was correlated with the suppression of c-Myc and Bcl-xL, which are the prime genes for cell cycle control and anti-apoptosis. Furthermore, we demonstrated that p21 negatively regulated the expression of c-Myc and Bcl-xL upon JQ1 treatment, and that the growth inhibition of SW 1353 and Hs 819.T cells and induction of p21 were predominantly regulated by the LATS1/YAP signaling but not through a p53-dependent manner. In conclusion, we disclosed a novel mechanism that JQ1 inhibits cell proliferation, induces cell senescence and apoptosis of chondrosarcoma cells through the regulation of the YAP/p21/c-Myc/Bcl-xL signaling axis. J. Cell. Biochem. 118: 2182-2192, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  8. 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. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. Significance of HER2 and C-MYC oncogene amplifications in breast cancer in atomic bomb survivors: associations with radiation exposure and histologic grade.

    Science.gov (United States)

    Miura, Shiro; Nakashima, Masahiro; Ito, Masahiro; Kondo, Hisayoshi; Meirmanov, Serik; Hayashi, Tomayoshi; Soda, Midori; Matsuo, Takeshi; Sekine, Ichiro

    2008-05-15

    It has been postulated that radiation induces breast cancers in atomic bomb (A-bomb) survivors. Oncogene amplification is an important mechanism during breast carcinogenesis and also serves as an indicator of genomic instability (GIN). The objective of this study was to clarify the association of oncogene amplification in breast cancer in A-bomb survivors with radiation exposure. In total, 593 breast cancers were identified in A-bomb survivors from 1968 to 1999, and the association between breast cancer incidence and A-bomb radiation exposure was evaluated. Invasive ductal cancers from 67 survivors and 30 nonsurvivors were analyzed for amplification of the HER2 and C-MYC genes by fluorescence in situ hybridization, and expression levels of hormone receptors were analyzed by immunostaining. The incidence rate increased significantly as exposure distance decreased from the hypocenter (hazard ratio per 1-km decrement, 1.47; 95% confidence interval [95% CI], 1.30-1.66). The incidence of HER2 and C-MYC amplification was increased significantly in the order of the control group, the distal group (P = .0238), and the proximal group (P = .0128). Multivariate analyses revealed that distance was a risk factor for the coamplification of C-MYC and HER2 in breast cancer in survivors (odds ratio per 1-km increment, 0.17; 95% CI, 0.01-0.63). The histologic grade of breast cancers became significantly higher in the order of the control group, the distal group, and the proximal group and was associated with oncogene amplifications. The current results suggested that A-bomb radiation may affect the development of oncogene amplification by inducing GIN and may be associated with a higher histologic grade in breast cancer among A-bomb survivors. (c) 2008 American Cancer Society.

  10. 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.

  11. Parallel folding topology-selective label-free detection and monitoring of conformational and topological changes of different G-quadruplex DNAs by emission spectral changes via FRET of mPPE-Ala-Pt(ii) complex ensembleElectronic supplementary information (ESI) available: Experimental details, electronic absorption spectra and resonance light scattering spectra of mPPE-Ala at different concentrations of 1; emission spectra and time-resolved emission decay profiles of mPPE-Ala at different concentrations of 1; parameters obtained from the emission spectra and time-resolved emission decay profiles of mPPE-Ala at different concentrations of 1; electronic absorption spectra of 1 at different concentrations of c-myc; circular dichroism (CD) spectrum of c-myc; electronic absorption spectra and UV melting profile of c-myc at different temperatures in the absence and in the presence of 1; table listing the UV melting temperatures of c-myc, bcl-2, c-kit1 and human telomeric DNA in the absence and in the presence of 1; emission spectra of mPPE-Ala-1 ensemble at different concentrations of c-myc-c, pre-formed duplex of c-myc and c-myc-c, pre-formed duplex of human telomeric DNA and complementary sequence of human telomeric DNA, bcl-2, c-kit1 and human telomeric DNA; CD spectra of pre-formed duplex of c-myc and c-myc-c at different concentrations of 1; emission spectra of 1 at different concentrations of c-myc; emission spectra of mPPE-Ala-1 ensemble at different concentrations of c-myc in the presence of 36% (v/v) PEG-200; changes in relative emission intensities of mPPE-Ala-1 ensemble at different concentrations of c-myc at different volume percentages of PEG-200; emission spectra of mPPE-Ala, 1 and mPPE-Ala-1 ensemble at different volume percentages of PEG-200; CD spectra of c-myc at different volume percentages of PEG-200; changes in relative emission intensities of mPPE-Ala-1 ensemble at different concentrations of human telomeric DNA at different volume percentages of PEG

    National Research Council Canada - National Science Library

    Chan, Kevin; Yik-Sham Chung, Clive; Wing-Wah Yam, Vivian

    2016-01-01

    ..., such as c-myc , in aqueous buffer solution. By the modulation of the aggregation/deaggregation of the polymer-metal complex aggregates and hence the FRET from the m PPE-Ala donor to the aggregated 1 as acceptor, the ensemble has been...

  12. Parallel folding topology-selective label-free detection and monitoring of conformational and topological changes of different G-quadruplex DNAs by emission spectral changes via FRET of mPPE-Ala-Pt(ii) complex ensembleElectronic supplementary information (ESI) available: Experimental details, electronic absorption spectra and resonance light scattering spectra of mPPE-Ala at different concentrations of 1; emission spectra and time-resolved emission decay profiles of mPPE-Ala at different concentrations of 1; parameters obtained from the emission spectra and time-resolved emission decay profiles of mPPE-Ala at different concentrations of 1; electronic absorption spectra of 1 at different concentrations of c-myc; circular dichroism (CD) spectrum of c-myc; electronic absorption spectra and UV melting profile of c-myc at different temperatures in the absence and in the presence of 1; table listing the UV melting temperatures of c-myc, bcl-2, c-kit1 and human telomeric DNA in the absence and in the presence of 1; emission spectra of mPPE-Ala-1 ensemble at different concentrations of c-myc-c, pre-formed duplex of c-myc and c-myc-c, pre-formed duplex of human telomeric DNA and complementary sequence of human telomeric DNA, bcl-2, c-kit1 and human telomeric DNA; CD spectra of pre-formed duplex of c-myc and c-myc-c at different concentrations of 1; emission spectra of 1 at different concentrations of c-myc; emission spectra of mPPE-Ala-1 ensemble at different concentrations of c-myc in the presence of 36% (v/v) PEG-200; changes in relative emission intensities of mPPE-Ala-1 ensemble at different concentrations of c-myc at different volume percentages of PEG-200; emission spectra of mPPE-Ala, 1 and mPPE-Ala-1 ensemble at different volume percentages of PEG-200; CD spectra of c-myc at different volume percentages of PEG-200; changes in relative emission intensities of mPPE-Ala-1 ensemble at different concentrations of human telomeric DNA at different volume percentages of PEG

    National Research Council Canada - National Science Library

    Chan, Kevin; Yik-Sham Chung, Clive; Wing-Wah Yam, Vivian

    2016-01-01

    ..., such as c-myc , in aqueous buffer solution. By the modulation of the aggregation/deaggregation of the polymer-metal complex aggregates and hence the FRET from the m PPE-Ala donor to the aggregated 1 as acceptor, the ensemble...

  13. Equol, an isoflavone metabolite, regulates cancer cell viability and protein synthesis initiation via c-Myc and eIF4G.

    Science.gov (United States)

    de la Parra, Columba; Borrero-Garcia, Luis D; Cruz-Collazo, Ailed; Schneider, Robert J; Dharmawardhane, Suranganie

    2015-03-06

    Epidemiological studies implicate dietary soy isoflavones as breast cancer preventives, especially due to their anti-estrogenic properties. However, soy isoflavones may also have a role in promoting breast cancer, which has yet to be clarified. We previously reported that equol, a metabolite of the soy isoflavone daidzein, may advance breast cancer potential via up-regulation of the eukaryotic initiation factor 4GI (eIF4GI). In estrogen receptor negative (ER-) metastatic breast cancer cells, equol induced elevated levels of eIF4G, which were associated with increased cell viability and the selective translation of mRNAs that use non-canonical means of initiation, including internal ribosome entry site (IRES), ribosome shunting, and eIF4G enhancers. These mRNAs typically code for oncogenic, survival, and cell stress molecules. Among those mRNAs translationally increased by equol was the oncogene and eIF4G enhancer, c-Myc. Here we report that siRNA-mediated knockdown of c-Myc abrogates the increase in cancer cell viability and mammosphere formation by equol, and results in a significant down-regulation of eIF4GI (the major eIF4G isoform), as well as reduces levels of some, but not all, proteins encoded by mRNAs that are translationally stimulated by equol treatment. Knockdown of eIF4GI also markedly reduces an equol-mediated increase in IRES-dependent mRNA translation and the expression of specific oncogenic proteins. However, eIF4GI knockdown did not reciprocally affect c-Myc levels or cell viability. This study therefore implicates c-Myc as a potential regulator of the cancer-promoting effects of equol via up-regulation of eIF4GI and selective initiation of translation on mRNAs that utilize non-canonical initiation, including certain oncogenes. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  14. Angiotensin II Reduces Cardiac AdipoR1 Expression through AT1 Receptor/ROS/ERK1/2/c-Myc Pathway

    Science.gov (United States)

    Lei, Hong; Wang, Cheng; Wu, Li-Peng; Wang, Jin-Yu; Fu, Feng-Ying; Zhu, Wei-Guo; Wu, Li-Ling

    2013-01-01

    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. PMID

  15. Knocking-down of CREPT prohibits the progression of oral squamous cell carcinoma and suppresses cyclin D1 and c-Myc expression.

    Directory of Open Access Journals (Sweden)

    Juntao Ma

    Full Text Available As a regulator essential for many cell cycle-related proteins, the robust expression of Cell cycle-Related and Expression-elevated Protein in Tumor (CREPT implicates a poor diagnosis of endoderm and mesoderm-derived tumors. Whether CREPT plays the same role in the tumorigenesis derived from ectodermal tissues remains elusive.To explore the role of CREPT in ectoderm-derived tumors, cells from 7oral squamous cell carcinoma (OSCC lines and 84clinical OSCC samples were exploited in this study. Quantitative PCR, Western blot assay and immunohistochemistry were applied in the evaluation of CREPT, cyclin D1 and c-Myc expression. Knocking-down of CREPT was performed by lentivirus delivering specific shRNA of CREPT. The effects of CREPT on OSCC were examined by cell proliferation, colony formation, apoptosis, cell migration and xenograft implantation experiments.Compared with human normal oral keratinocytes, OSCC cell lines showed a significantly elevated expression of CREPT in both mRNA and protein levels. Consistently, samples from OSCC patients also exhibited a noticeably stronger CREPT expression than the noncancerous samples. In contrast, knocking down of CREPT in OSCC cell lines significantly reduced proliferation, colony formation and migration as well as the expression of cyclin D1 and c-Myc, but promoted apoptosis. Statistical analysis also suggested that CREPT expression was significantly correlated with the T and N classification of OSCC. Furthermore, CAL27 mouse xenograft model confirmed that down-regulation of CREPT prohibited cyclin D1 and c-Myc expression, through which decreased the in vivo tumor growth, but increased the survival ratio of hosts.In OSCC cell lines, up-regulated CREPT expression enhanced cell proliferation, migration and cell cycle as well as promoted cyclin D1 and c-Myc expression as it did in endoderm and mesoderm-origin tumors. Our study strongly suggests that CREPT could be used as a marker for the OSCC prognosis and

  16. 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.

  17. Telomere length modulation in human astroglial brain tumors.

    Directory of Open Access Journals (Sweden)

    Domenico La Torre

    Full Text Available BACKGROUND: Telomeres alteration during carcinogenesis and tumor progression has been described in several cancer types. Telomeres length is stabilized by telomerase (h-TERT and controlled by several proteins that protect telomere integrity, such as the Telomere Repeat-binding Factor (TRF 1 and 2 and the tankyrase-poli-ADP-ribose polymerase (TANKs-PARP complex. OBJECTIVE: To investigate telomere dysfunction in astroglial brain tumors we analyzed telomeres length, telomerase activity and the expression of a panel of genes controlling the length and structure of telomeres in tissue samples obtained in vivo from astroglial brain tumors with different grade of malignancy. MATERIALS AND METHODS: Eight Low Grade Astrocytomas (LGA, 11 Anaplastic Astrocytomas (AA and 11 Glioblastoma Multiforme (GBM samples were analyzed. Three samples of normal brain tissue (NBT were used as controls. Telomeres length was assessed through Southern Blotting. Telomerase activity was evaluated by a telomere repeat amplification protocol (TRAP assay. The expression levels of TRF1, TRF2, h-TERT and TANKs-PARP complex were determined through Immunoblotting and RT-PCR. RESULTS: LGA were featured by an up-regulation of TRF1 and 2 and by shorter telomeres. Conversely, AA and GBM were featured by a down-regulation of TRF1 and 2 and an up-regulation of both telomerase and TANKs-PARP complex. CONCLUSIONS: In human astroglial brain tumours, up-regulation of TRF1 and TRF2 occurs in the early stages of carcinogenesis determining telomeres shortening and genomic instability. In a later stage, up-regulation of PARP-TANKs and telomerase activation may occur together with an ADP-ribosylation of TRF1, causing a reduced ability to bind telomeric DNA, telomeres elongation and tumor malignant progression.

  18. Zonisamide regulates basal ganglia transmission via astroglial kynurenine pathway.

    Science.gov (United States)

    Fukuyama, Kouji; Tanahashi, Shunske; Hoshikawa, Masamitsu; Shinagawa, Rika; Okada, Motohiro

    2014-01-01

    To clarify the anti-parkinsonian mechanisms of action of zonisamide (ZNS), we determined the effects of ZNS on tripartite synaptic transmission associated with kynurenine (KYN) pathway (KP) in cultured astrocytes, and transmission in both direct and indirect pathways of basal ganglia using microdialysis. Interactions between cytokines [interferon-γ (IFNγ) and tumor-necrosis factor-α (TNFα)] and ZNS on astroglial releases of KP metabolites, KYN, kynurenic-acid (KYNA), xanthurenic-acid (XTRA), cinnabarinic-acid (CNBA) and quinolinic-acid (QUNA), were determined by extreme liquid-chromatography with mass-spectrometry. Interaction among metabotropic glutamate-receptor (mGluR), KP metabolites and ZNS on striato-nigral, striato-pallidal GABAergic and subthalamo-nigral glutamatergic transmission was examined by microdialysis with extreme liquid-chromatography fluorescence resonance-energy transfer detection. Acute and chronic ZNS administration increased astroglial release of KYN, KYNA, XTRA and CNBA, but not QUNA. Chronic IFNγ administration increased the release of KYN, KYNA, CNBA and QUNA, but had minimal inhibitory effect on XTRA release. Chronic TNFα administration increased CNBA and QUNA, but not KYN, KYNA or XTRA. ZNS inhibited IFNγ-induced elevation of KYN, KYNA and QUNA, but enhanced IFNγ-induced that of CNBA. TNFα-induced rises in CNBA and QUNA were inhibited by ZNS. ZNS inhibited striato-nigral GABAergic, striato-pallidal GABAergic and subthalamo-nigral glutamatergic transmission via activation of groups II and III mGluRs. ZNS enhanced astroglial release of endogenous agonists of group II mGluR, XTRA and group III mGluR, CNBA. Activated endogenous mGluR agonists inhibited transmission in direct and indirect pathways of basal ganglia. These mechanisms contribute to effectiveness and well tolerability of ZNS as an adjunct treatment for Parkinson's disease during l-DOPA monotherapy. This article is part of the Special Issue entitled 'The Synaptic Basis of

  19. Cultures of astroglial cells derived from brain of adult cichlid fish.

    Science.gov (United States)

    Mack, Andreas F; Tiedemann, Karin

    2013-01-30

    Astroglial cells in teleost fish occur mostly as radial glia. We established a culture system derived from brain tissue of mature cichlid fish Astatotilapia burtoni to study fish astroglial cells in more detail. Cells were passaged several times to expand the cultures, and could be kept in vitro for several months. The cell identity was tested by the presence of glial fibrillary acidic protein (GFAP); in addition, cells expressed the tight junction adaptor protein zonula occludens-1 (ZO-1) known to be present on astroglial cells in fish brain. This is consistent with the radial and epithelial nature of fish astroglial cells derived from neuroepithelium. To characterize the properties of cultured astroglial cells we challenged them in hypo-osmotic conditions. Cells reacted with volume increase, slower but similar to mammalian astrocytes. We also tested whether astroglial cells support growth during axonal elongation. We placed retinal explants on astroglial cultures and found neurites extending readily on these cells, compared to controls which showed no or little growth. Thus, we established a culture system for astroglial cells from the mature fish brain that demonstrates their neuroepithelial properties. This culture system will be useful to study functions in which glial cells are thought to play an important role: e.g. regulation of water homeostasis and supporting axonal regeneration. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. 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.

  1. miR-23b/SP1/c-myc forms a feed-forward loop supporting multiple myeloma cell growth.

    Science.gov (United States)

    Fulciniti, M; Amodio, N; Bandi, R L; Cagnetta, A; Samur, M K; Acharya, C; Prabhala, R; D'Aquila, P; Bellizzi, D; Passarino, G; Adamia, S; Neri, A; Hunter, Z R; Treon, S P; Anderson, K C; Tassone, P; Munshi, N C

    2016-01-15

    Deregulated microRNA (miR)/transcription factor (TF)-based networks represent a hallmark of cancer. We report here a novel c-Myc/miR-23b/Sp1 feed-forward loop with a critical role in multiple myeloma (MM) and Waldenstrom's macroglobulinemia (WM) cell growth and survival. We have found miR-23b to be downregulated in MM and WM cells especially in the presence of components of the tumor bone marrow milieu. Promoter methylation is one mechanism of miR-23b suppression in myeloma. In gain-of-function studies using miR-23b mimics-transfected or in miR-23b-stably expressing MM and WM cell lines, we observed a significant decrease in cell proliferation and survival, along with induction of caspase-3/7 activity over time, thus supporting a tumor suppressor role for miR-23b. At the molecular level, miR-23b targeted Sp1 3'UTR and significantly reduced Sp1-driven nuclear factor-κB activity. Finally, c-Myc, an important oncogenic transcription factor known to stimulate MM cell proliferation, transcriptionally repressed miR-23b. Thus MYC-dependent miR-23b repression in myeloma cells may promote activation of oncogenic Sp1-mediated signaling, representing the first feed-forward loop with critical growth and survival role in myeloma.

  2. Expression of c-erbB-2, p53 and c-myc proteins in male breast carcinoma: Comparison with traditional prognostic factors and survival

    Directory of Open Access Journals (Sweden)

    Mourão Netto M.

    2001-01-01

    Full Text Available There are few data evaluating biological markers for men with breast cancer. The purpose of the present study was to analyze the expression of the oncogenes c-erbB-2 and c-myc and of the suppressor gene p53 by immunohistochemical techniques in archival paraffin-embedded tissue blocks of 48 male breast cancer patients, treated at the A.C. Camargo Cancer Hospital, São Paulo, SP, Brazil. The results were compared with clinicopathological prognostic features. Immunopositivity of c-erbB-2, p53 and c-myc was detected in 62.5, 16.7 and 20.8% of the cases analyzed, respectively. Estrogen and progesterone receptors were positive in 75 and 69% of the cases, respectively. Increasing staging was statistically associated with c-erbB-2 (P = 0.04 and weakly related to p53 positivity (P = 0.06. No significant correlation between specific survival rate (determined by the log rank test and the molecular markers analyzed was found, whereas the number of compromised lymph nodes and advanced TNM (tumor, node, metastasis staging were associated with diminished survival.

  3. Expression Analysis of p16, c-Myc, and mSin3A in Non-small Cell Lung Cancer by Computer Aided Scoring and Analysis (CASA).

    Science.gov (United States)

    Salmaninejad, Arash; Estiar, Mehrdad Asghari; Gill, Rajbir K; Shih, Joanna H; Hewitt, Stephen; Jeon, Hyo-Sung; Fukuoka, Junya; Shilo, Konstantin; Shakoori, Abbas; Jen, Jin

    2015-01-01

    Immunohistochemical analysis (IHC) of tissue microarray (TMA) slides enables large sets of tissue samples to be analyzed simultaneously on a single slide. However, manual evaluation of small cores on a TMA slide is time consuming and error prone. We describe a computer aided scoring and analysis (CASA) method to allow facile and reliable scoring of IHC staining using TMA containing 300 non-small cell lung cancer (NSCLC) cases. In the two previous published papers utilizing our TMA slides of lung cancer we examined 18 proteins involved in the chromatin machinery. We developed our study using more proteins of the chromatin complex and several transcription factors that facilitate the chromatin machinery. Then, a total of 78 antibodies were evaluated by CASA to derive a normalized intensity value that correlated with the overall staining status of the targeting protein. The intensity values for TMA cores were then examined for association to clinical variables and predictive significance individually and with other factors. RESULTs: Using our TMA, the intensity of several protein pairs were significantly correlated with an increased risk of death in NSCLC. These included c-Myc with p16, mSin3A with p16 and c-Myc with mSinA. Predictive values of these pairs remained significant when evaluated based on standard IHC scores. Our results demonstrate the usefulness of CASA as a valuable tool for systematic assessment of TMA slides to identify potential predictive biomarkers using a large set of primary human tissues.

  4. Real-time monitoring of PCR amplification of proto-oncogene c-MYC using a Ta₂O₅ electrolyte-insulator-semiconductor sensor.

    Science.gov (United States)

    Branquinho, Rita; Veigas, Bruno; Pinto, Joana V; Martins, Rodrigo; Fortunato, Elvira; Baptista, Pedro V

    2011-10-15

    We present a new approach for real-time monitoring of PCR amplification of a specific sequence from the human c-MYC proto-oncogene using a Ta(2)O(5) electrolyte-insulator-semiconductor (EIS) sensor. The response of the fabricated EIS sensor to cycle DNA amplification was evaluated and compared to standard SYBR-green fluorescence incorporation, showing it was possible to detect DNA concentration variations with 30 mV/μM sensitivity. The sensor's response was then optimized to follow in real-time the PCR amplification of c-MYC sequence from a genomic DNA sample attaining an amplification profile comparable to that of a standard real-time PCR. Owing to the small size, ease of fabrication and low-cost, the developed Ta(2)O(5) sensor may be incorporated onto a microfluidic device and then used for real-time PCR. Our approach may circumvent the practical and economical obstacles posed by current platforms that require an external fluorescence detector difficult to miniaturize and incorporate into a lab-on-chip system. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Proteomic Characterization of the World Trade Center dust-activated mdig and c-myc signaling circuit linked to multiple myeloma.

    Science.gov (United States)

    Wu, Kai; Li, Lingzhi; Thakur, Chitra; Lu, Yongju; Zhang, Xiangmin; Yi, Zhengping; Chen, Fei

    2016-11-11

    Several epidemiological studies suggested an increased incidence rate of multiple myeloma (MM) among first responders and other individuals who exposed to World Trade Center (WTC) dust. In this report, we provided evidence showing that WTC dust is potent in inducing mdig protein and/or mRNA in bronchial epithelial cells, B cells and MM cell lines. An increased mdig expression in MM bone marrow was observed, which is associated with the disease progression and prognosis of the MM patients. Through integrative genomics and proteomics approaches, we further demonstrated that mdig directly interacts with c-myc and JAK1 in MM cell lines, which contributes to hyperactivation of the IL-6-JAK-STAT3 signaling important for the pathogenesis of MM. Genetic silencing of mdig reduced activity of the major downstream effectors in the IL-6-JAK-STAT3 pathway. Taken together, these data suggest that WTC dust may be one of the key etiological factors for those who had been exposed for the development of MM by activating mdig and c-myc signaling circuit linked to the IL-6-JAK-STAT3 pathway essential for the tumorigenesis of the malignant plasma cells.

  6. Histone deacetylase inhibitor romidepsin induces efficient tumor cell lysis via selective down-regulation of LMP1 and c-myc expression in EBV-positive diffuse large B-cell lymphoma.

    Science.gov (United States)

    Shin, Dong-Yeop; Kim, Areumnuri; Kang, Hye Jin; Park, Sunhoo; Kim, Dong Wan; Lee, Seung-Sook

    2015-08-10

    We investigated the role of the histone deacetylase inhibitor, romidepsin, in Epstein-Barr virus (EBV)-positive diffuse large B-cell lymphoma (DLBCL), an aggressive non-Hodgkin lymphoma with poor clinical outcomes. We used EBV-positive and EBV-negative DLBCL cell lines and generated two EBV-transfected cell lines, LY7/EBV and U2932/EBV. Romidepsin was cytotoxic to cultured EBV-positive cells via the activation of the caspase cascade. Moreover, in vivo mice xenograft models demonstrated the cytotoxicity of romidepsin to EBV-positive DLBCL cells. Romidepsin induced cytotoxicity via the reduction of LMP1 and c-myc expression in EBV-positive cells. Inhibiting either LMP1 or c-myc using small inhibitory RNAs caused partial cytotoxicity in EBV-positive Farage and U2932/EBV lines. The dual inhibition of LMP1 and c-myc showed a synergistic cytotoxic effect in EBV-positive cells similar in magnitude to that of romidepsin alone. In addition, either double blockade of LMP1 and c-myc activity or romidepsin single treatment activated EBV lytic cycle in EBV-positive cells. In conclusion, romidepsin exerts strong anti-tumor activity in EBV-positive DLBCL via the inhibition of both LMP1 and c-myc. Our findings indicate that romidepsin might be a promising treatment for EBV-positive DLBCL. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  7. Activity-Dependent Plasticity of Astroglial Potassium and Glutamate Clearance

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    Giselle Cheung

    2015-01-01

    Full Text Available Recent evidence has shown that astrocytes play essential roles in synaptic transmission and plasticity. Nevertheless, how neuronal activity alters astroglial functional properties and whether such properties also display specific forms of plasticity still remain elusive. Here, we review research findings supporting this aspect of astrocytes, focusing on their roles in the clearance of extracellular potassium and glutamate, two neuroactive substances promptly released during excitatory synaptic transmission. Their subsequent removal, which is primarily carried out by glial potassium channels and glutamate transporters, is essential for proper functioning of the brain. Similar to neurons, different forms of short- and long-term plasticity in astroglial uptake have been reported. In addition, we also present novel findings showing robust potentiation of astrocytic inward currents in response to repetitive stimulations at mild frequencies, as low as 0.75 Hz, in acute hippocampal slices. Interestingly, neurotransmission was hardly affected at this frequency range, suggesting that astrocytes may be more sensitive to low frequency stimulation and may exhibit stronger plasticity than neurons to prevent hyperexcitability. Taken together, these important findings strongly indicate that astrocytes display both short- and long-term plasticity in their clearance of excess neuroactive substances from the extracellular space, thereby regulating neuronal activity and brain homeostasis.

  8. Specification of Transplantable Astroglial Subtypes from Human Pluripotent Stem Cells

    Science.gov (United States)

    Krencik, Robert; Weick, Jason P.; Liu, Yan; Zhang, Zhijian; Zhang, Su-Chun

    2011-01-01

    Functionally diversified neuronal populations have now been efficiently generated from human pluripotent stem cells (hPSCs). However, directed differentiation of hPSCs to functional astroglial subtypes remains elusive. In this study, hPSCs were successfully directed to nearly uniform populations of immature astrocytes in large quantities (>90% S100β+ and GFAP+). The immature human astrocytes exhibit similar gene expression patterns as primary astrocytes, display functional properties such as glutamate uptake and promotion of synaptogenesis, and become mature astrocytes by forming connections with blood vessels following transplantation into the mouse brain. Furthermore, hPSC-derived neuroepithelia, patterned to rostral-caudal and dorsal-ventral identities with the same morphogens used for neuronal subtype specification, generate immature astrocytes that carry distinct homeodomain transcription factors and display phenotypic differences. These human astroglial progenitors and immature astrocytes will be instrumental for studying astrocytes in brain development and function, for revealing their roles in disease processes, and for developing novel treatments for neurological disorders. PMID:21602806

  9. Concordant genetic distinctness of the phylogroup of the Siberian chipmunk from the Korean peninsula (Tamias sibiricus barberi), reexamined with nuclear DNA c-myc gene exon 2 and mtDNA control region sequences.

    Science.gov (United States)

    Koh, Hung Sun; Zhang, Minghai; Bayarlkhagva, Damdingiin; Ham, Eui Jeong; Kim, Jin Seong; Jang, Kyung Hee; Park, Nam Jeong

    2010-08-01

    We reexamined Tamias sibiricus barberi from Korea by sequencing c-myc exon 2 and the mtDNA control region. In the c-myc exon, the monogenic T. s. barberi differed from the monogenic T. s. orientalis (nucleotide distance 0.48%; 3 variable sites at 168, 306, and 552), whereas T. s. orientalis was identical to T. s. sibiricus. In the control region, T. s. barberi differed from T. s. orientalis (distance 6.84%) and T. s. sibiricus (9.35%). We considered the concordant, extensive gaps between the phylogroup of T. s. barberi and other subspecies of T. sibiricus in the c-myc gene, control region, and cytochrome b gene to be evidence of a lack of intergradation through North Korea from T. s. barberi to T. s. orientalis. Our results, showing the genetic and morphological distinctness of T. s. barberi, support that this phylogroup is a distinct species.

  10. Orientation and position of avian leukosis virus DNA relative to the cellular oncogene c-myc in B-lymphoma tumors of highly susceptible 15I5 X 7(2) chickens.

    Science.gov (United States)

    Fung, Y K; Crittenden, L B; Kung, H J

    1982-01-01

    We previously reported our characterizations of the B-lymphoma tumors induced in a highly susceptible line of chickens (15I5 X 7(2)) by the avian leukosis virus RAV-1 (Proc. Natl. Acad. Sci. 78:3418-3422, 1981). We demonstrated that in greater than 90% of the tumors, the RAV-1 provirus is integrated near a cellular oncogene, c-myc. In the present study, we devised a simple approach, relying on SalI digestion, for further defining the locations and orientations of the proviruses with respect to the c-myc gene. We report here that in the great majority of cases the provirus is situated upstream from and in the same transcriptional direction as the c-myc gene--a configuration compatible with the promoter-insertion model proposed by Hayward et al. (Nature [London] 290:475-480, 1981). Images PMID:6292531

  11. 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

  12. Human adipose tissue-derived stem cells cultured in xeno-free culture condition enhance c-MYC expression increasing proliferation but bypassing spontaneous cell transformation.

    Science.gov (United States)

    Paula, Ana C C; Martins, Thaís M M; Zonari, Alessandra; Frade, Soraia P P J; Angelo, Patrícia C; Gomes, Dawidson A; Goes, Alfredo M

    2015-04-14

    Human adipose tissue-derived stem cells (hASCs) are attractive cells for therapeutic applications and are currently being evaluated in multiple clinical trials. Prior to their clinical application, hASCs must be expanded ex vivo to obtain the required number of cells for transplantation. Fetal bovine serum is the supplement most widely used for cell culture, but it has disadvantages and it is not safe for cell therapy due to the risks of pathogen transmission and immune reaction. Furthermore, the cell expansion poses a risk of accumulating genetic abnormalities that could lead to malignant cell transformation. In this study, our aim was to evaluate the proliferation pattern as well as the resistance to spontaneous transformation of hASCs during expansion in a xeno-free culture condition. hASCs were expanded in Dulbecco's modified Eagle's medium supplemented with pooled allogeneic human serum or fetal bovine serum to enable a side-by-side comparison. Cell viability and differentiation capacity toward the mesenchymal lineages were assessed, along with immunophenotype. Ki-67 expression and the proliferation kinetics were investigated. The expression of the transcription factors c-FOS and c-MYC was examined with Western blot, and MYC, CDKN2A, ERBB2 and TERT gene expression was assessed with quantitative PCR. Senescence was evaluated by β-gal staining. Karyotype analysis was performed and tumorigenesis assay in vivo was also evaluated. The hASCs expanded in medium with pooled allogeneic human serum did not show remarkable differences in morphology, viability, differentiation capacity or immunophenotype. The main difference observed was a significantly higher proliferative effect on hASCs cultured in pooled allogeneic human serum. There was no significant difference in C-FOS expression; however, C-MYC protein expression was enhanced in pooled allogeneic human serum cultures compared to fetal bovine serum cultures. No difference was observed in MYC and TERT mRNA levels

  13. Tumor-suppressive microRNA-135a inhibits cancer cell proliferation by targeting the c-MYC oncogene in renal cell carcinoma.

    Science.gov (United States)

    Yamada, Yasutoshi; Hidaka, Hideo; Seki, Naohiko; Yoshino, Hirofumi; Yamasaki, Takeshi; Itesako, Toshihiko; Nakagawa, Masayuki; Enokida, Hideki

    2013-03-01

    Recently, many studies have suggested that microRNAs (miRNAs) are involved in cancer cell development, invasion, and metastasis of various types of human cancers. In a previous study, miRNA expression signatures from renal cell carcinoma (RCC) revealed that expression of microRNA-135a (miR-135a) was significantly reduced in cancerous tissues. The aim of this study was to investigate the functional significance of miR-135a and to identify miR-135a-mediated molecular pathways in RCC cells. Restoration of mature miR-135a significantly inhibited cancer cell proliferation and induced G0 /G1 arrest in the RCC cell lines caki2 and A498, suggesting that miR-135a functioned as a potential tumor suppressor. We then examined miR-135a-mediated molecular pathways using genome-wide gene expression analysis and in silico analysis. A total of 570 downregulated genes were identified in miR-135a transfected RCC cell lines. To investigate the biological significance of potential miR-135a-mediated pathways, we classified putative miR-135a-regulated genes according to the Kyoto Encyclopedia of Genes and Genomics pathway database. From our in silico analysis, 25 pathways, including the cell cycle, pathways in cancer, DNA replication, and focal adhesion, were significantly regulated by miR-135a in RCC cells. Moreover, based on the results of this analysis, we investigated whether miR-135a targeted the c-MYC gene in RCC. Gain-of-function and luciferase reporter assays showed that c-MYC was directly regulated by miR-135a in RCC cells. Furthermore, c-MYC expression was significantly upregulated in RCC clinical specimens. Our data suggest that elucidation of tumor-suppressive miR-135a-mediated molecular pathways could reveal potential therapeutic targets in RCC. © 2012 Japanese Cancer Association.

  14. 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.

    Science.gov (United States)

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

    2010-09-24

    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 transformed cells was parallel to that of DJ-1. These findings indicate that DJ-1 is essential for SV40 transformation. Copyright © 2010 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  15. 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.

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

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    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.

  17. Spontaneous DNA lesions modulate DNA structural transitions occurring at nuclease hypersensitive element III(1) of the human c-myc proto-oncogene.

    Science.gov (United States)

    Beckett, Joshua; Burns, Jacob; Broxson, Christopher; Tornaletti, Silvia

    2012-07-03

    G quadruplex (G4) DNA is a noncanonical four-stranded DNA structure that can form in G repeats by stacking of planar arrays of four hydrogen-bonded guanines called G quartets, in the presence of potassium ions. In addition to a presumed function in the regulation of gene expression, G4 DNA also localizes to regions often characterized by genomic instability. This suggests that formation of this structure may interfere with DNA transactions, including processing of DNA damage at these sites. Here we have studied the effect of two spontaneous DNA lesions, the abasic site and 8-oxoguanine, on the transition from duplex to quadruplex DNA structure occurring at nuclease hypersensitive element III(1) (NHEIII(1)) of the human c-myc promoter. We show by dimethyl sulfate footprinting and RNA polymerase arrest assays that at physiological concentrations of potassium ions NHEIII(1) folds into two coexisting G4 DNA structures, myc-1245 and myc-2345, depending on which G runs are utilized for G quartet formation. We found that a single substitution of G12 of NHEIII(1) with a single abasic site or a single 8-oxoguanine prevented formation of G4 structure myc-2345 in favor of structure myc-1245, where the lesion was accommodated in a DNA loop formed by G11-AP12/(or 8-oxoG12)-G13-G14. Surprisingly, when an additional G to A base substitution was introduced at position 3 of NHEIII(1), we observed formation of myc-2345. The extent of this structural transition was modulated by the location and type of lesion within the G11-G14 repeat. Our data indicate that spontaneous lesions formed in the G4-forming sequence of c-myc NHEIII(1) affect the structural transitions occurring at this regulatory site, potentially altering transcription factor binding and DNA repair of lesions formed in this highly regulated sequence.

  18. 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.

  19. EZH2 overexpression in primary gastrointestinal diffuse large B-cell lymphoma and its association with the clinicopathological features.

    Science.gov (United States)

    Liu, Yang; Yu, Kangjie; Li, Mingyang; Zeng, Kaixuan; Wei, Jie; Li, Xia; Liu, Yixiong; Zhao, Danhui; Fan, Linni; Yu, Zhou; Wang, Yingmei; Li, Zengshan; Zhang, Wei; Bai, Qingxian; Yan, Qingguo; Guo, Ying; Wang, Zhe; Guo, Shuangping

    2017-06-01

    Gastrointestinal diffuse large B-cell lymphoma (GI DLBCL) is the most common gastrointestinal lymphoma. Enhancer of zeste homolog 2 (EZH2) has been implicated in the pathogenesis of several cancers. However, EZH2 has not been studied in GI DLBCL. Thus, we investigated EZH2 expression and EZH2 Y641 mutation in 100 GI DLBCL specimens by immunohistochemistry and sequencing. In addition, trimethylated H3K27 (H3K27me3), BCL2, c-MYC, and Ki-67 expression and Helicobacter pylori infection were detected, and BCL2 and c-MYC gene translocation was assessed. EZH2 was overexpressed in 50% of cases. EZH2 overexpression was significantly associated with higher stage (P = .014), higher International Prognostic Index score (P = .003), reduced overall survival rate (P = .030), and H3K27me3 (P = .001) and c-MYC expression (P = .008). We detected EZH2 mutations in 1 of 33 (3.0%) DLBCLs with a germinal center immunophenotype. The frequency of EZH2 Y641 mutation in GI DLBCL was significantly lower than that in patients with DLBCL without gastrointestinal features (P = .022). BCL2 and c-MYC translocation was detected in 6.5% and 5.1% of cases, respectively. BCL2 translocation was detected exclusively in the germinal center B-cell-like subtype. Chronic gastroenteritis was present in all cases, and 36.4% of gastric DLBCL cases had H pylori infection. The data indicate that primary GI DLBCL is closely related with chronic inflammation and has a low frequency of molecular abnormality, and EZH2 overexpression is significantly associated with inferior outcome in patients with primary GI DLBCL; evaluating EZH2 expression has therapeutic implications. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Induction of c-myc and c-jun proto-oncogene expression in rat L6 myoblasts by cadmium is inhibited by zinc preinduction of the metallothionein gene

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    Abshire, M.K.; Buzard, G.S.; Shiraishi, Noriyuki; Waalkers, M.P. [National Cancer Institute, Fredrick, MD (United States)

    1996-07-01

    Certain proto-oncogenes transfer growth regulatory signals from the cell surface to the nucleus. These genes often show activation soon after cells are exposed to mitogenic stimulation but can also be activated as a nonmitogenic stress response. Cadmium (Cd) is a carcinogenic metal in humans and rodents and, though its mechanism of action is unknown, it could involve activation of such proto-oncogenes. Metallothionein (MT), a metal-inducible protein that binds Cd, can protect against many aspects of Cd toxicity, including genotoxicity and possibly carcinogenesis. Thus, the effects of Cd on expression of c-myc and c-jun in rat L6 myoblasts, and the effect of preactivation of the MT gene by Zn treatment on such oncogene expression, were studied. MT protein levels were measured using oligonucleotide hybridization and standardized to {beta}-actin levels. Cd (5 {mu}M CdCl{sub 2}, 0-30 h) stimulated both c-myc and c-jun mRNA expression. An initial peak of activation of c-myc expression occurred 2 h after initiation of Cd exposure, and levels remained elevated throughout the assessment period. Zn pretreatment markedly reduced the activation of c-myc expression by Cd compared to cells not receiving Zn pretreatment. Cd treatment increased c-jun mRNA levels by up to 3.5-fold. Again, Zn pretreatment markedly reduced. 10 refs., 8 figs.

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

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    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.

  2. Not All G-Quadruplexes are Created Equally: An Investigation of the Structural Polymorphism of the c-Myc G-Quadruplex-Forming Sequence and its Interaction with the Porphyrin meso-Tetra(N-methyl-4-pyridyl)porphine

    Science.gov (United States)

    Le, Huy T.; Miller, M. Clarke; Buscaglia, Robert; Dean, William L.; Holt, Patrick A.; Chaires, Jonathan B.; Trent, John O.

    2012-01-01

    G-quadruplexes, DNA tertiary structures highly localized to functionally important sites within the human genome, have emerged as important new drug targets. The putative G-quadruplex-forming sequence (Pu27) in the NHE-III1 promoter region of the c-Myc gene is of particular interest as stabilization of this G-quadruplex with TMPyP4 has been shown to repress c-Myc transcription. In this study, we examine the Pu27 G-quadruplex-forming sequence and its interaction with TMPyP4. We report that the Pu27 sequence exists as a heterogeneous mixture of monomeric and higher-order G-quadruplex species in vitro and that this mixture can be partially resolved by size exclusion chromatography (SEC) separation. Within this ensemble of configurations, the equilibrium can be altered by modifying the buffer composition, annealing procedure, and dialysis protocol thereby affecting the distribution of G-quadruplex species formed. TMPyP4 was found to bind preferentially to higher-order G-quadruplex species suggesting the possibility of stabilization of the junctions of the c-Myc G-quadruplex multimers by porphyrin end-stacking. We also examined four modified c-Myc sequences that have been previously reported and found a narrower distribution of quadruplex configurations compared to the parent Pu27 sequence. We could not definitively conclude whether these G-quadruplex structures were selected from the original ensemble or if they are new G-quadruplex structures. Since these sequences differ considerably from the wild-type promoter sequence, it is unclear whether their structures have any actual biological relevance. Additional studies are needed to examine how the polymorphic nature of G-quadruplexes affects the interpretation of in vitro data for c-Myc and other G-quadruplexes. The findings reported here demonstrate that experimental conditions contribute significantly to G-quadruplex formation and should be carefully considered, controlled, and reported in detail. PMID:23108607

  3. Conversion of androgen receptor signaling from a growth suppressor in normal prostate epithelial cells to an oncogene in prostate cancer cells involves a gain of function in c-Myc regulation.

    Science.gov (United States)

    Vander Griend, Donald J; Litvinov, Ivan V; Isaacs, John T

    2014-01-01

    In normal prostate, androgen-dependent androgen receptor (AR) signaling within prostate stromal cells induces their secretion of paracrine factors, termed "andromedins" which stimulate growth of the epithelial cells. The present studies demonstrate that androgen-dependent andromedin-driven growth stimulation is counter-balanced by androgen-induced AR signaling within normal adult prostate epithelial cells resulting in terminal G0 growth arrest coupled with terminal differentiation into ΔNp63-negative, PSA-expressing secretory luminal cells. This cell autonomous AR-driven terminal differentiation requires DNA-binding of the AR protein, is associated with decreases in c-Myc m-RNA and protein, are coupled with increases in p21, p27, and SKP-2 protein expression, and does not require functional p53. These changes result in down-regulation of Cyclin D1 protein and RB phosphoryation. shRNA knockdown documents that neither RB, p21, p27 alone or in combination are required for such AR-induced G0 growth arrest. Transgenic expression of a constitutive vector to prevent c-Myc down-regulation overrides AR-mediated growth arrest in normal prostate epithelial cells, which documents that AR-induced c-Myc down-regulation is critical in terminal growth arrest of normal prostate epithelial cells. In contrast, in prostate cancer cells, androgen-induced AR signaling paradoxically up-regulates c-Myc expression and stimulates growth as documented by inhibition of both of these responses following exposure to the AR antagonist, bicalutamide. These data document that AR signaling is converted from a growth suppressor in normal prostate epithelial cells to an oncogene in prostate cancer cells during prostatic carcinogenesis and that this conversion involves a gain of function for regulation of c-Myc expression.

  4. Controlled and localized delivery of c-myc AS-ODN to cells by 3-aminopropyl-trimethoxylsilane modified SBA-15 mesoporous silica

    Science.gov (United States)

    Zhang, Juan; Chen, Minmin; Zhao, Xiqiu; Zhang, Min; Mao, Jinxiang; Cao, Xichuan; Zhang, Zhuoqi

    2018-01-01

    SBA-15 mesoporous silicate was synthesized and functionalized with 3-aminopropyl organic groups through a post-synthesis method. The materials were characterized consecutively by powder X-ray diffraction (XRD), N2 adsorption/desorption analysis and solid-state magic-angle spinning 29Si nuclear magnetic resonance (MAS NMR). Human c-myc anti-sense oligodeoxyneucleotide (AS-ODN) was selected as a model molecule to be loaded onto the surface of bare and functionalized SBA-15 via different loading conditions. It has been found that the amount of AS-ODN incorporated into the porous matrix is strongly dependent on the surface properties, pH of the loading solvent and AS-ODN concentration. The release behaviour of AS-ODN from modified SBA-15 materials was also investigated and depended on conditions chosen. Cellular uptake of the eluted AS-ODN into Hela cells was observed by fluorescent microscopy. The materials showed excellent cytocompatibility. The AS-ODN keeps full transfection and expression activities indicating its structural integrity. The functionalized SBA-15 is an excellent prospect as a biomedical material candidate for the future.

  5. 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, Pmelatonin in adipose tissue. Melatonin also promoted cell cycle and increased cell numbers (PMelatonin also attenuated circadian disruption and promoted adipocyte proliferation in chronic jet-lagged mice and obese mice. Thus, our study found that melatonin promoted adipocyte proliferation by forming a Clock/HDAC3/c-Myc complex and subsequently driving the circadian amplitudes of proliferation genes. Our data reveal a novel mechanism that links circadian rhythm to cell proliferation in adipose tissue. These findings also identify a new potential means for melatonin to prevent and treat sleep deprivation-caused obesity. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. [Effects of lithium chloride and harringtonine on the differentiation, proliferation and c-myc proto-oncogene expression of HL-60 cells].

    Science.gov (United States)

    Li, W; Jiang, D; Tan, M

    1997-05-01

    This research was to observe the effects of lithium chloride (LiCl) and Harringtonine (HT) on the proliferation and differentiation of HL-60 leukemia cells. The results obtained by liquid suspension culture, semi-solid colony culture and 3H-TdR incorporation into HL-60 cells indicated that different concentrations of LiCl (5-20 mmol/L) and HT (10(-8)-10(-5)mol/L) exerted the inhibitory effects in a dose-dependent manner on HL-60 cell proliferation respectively. When LiCl (10 mmol/L) and HT (10(-7) mol/L) were added together in the liquid culture or semi-solid culture of HL-60 cells, they showed much greater inhibitory effect than that by each agent separately. It was discovered that there was induction of the differentiation of HL-60 cells by lithium and HT and the induction of HL-60 cells differentiation by HT was markedly enhanced by the addition of low concentration of lithium. This work also showed that by treating HL-60 cells with lithium and HT, the expression of the c-myc proto-oncogene was markedly decreased as measured by RT/PCR-mRNA (P lithium and HT in the treatment of leukemia and in vitro purging of leukemic cells for autologous bone marrow transplantation.

  7. Synthetic artificial microRNAs targeting UCA1-MALAT1 or c-Myc inhibit malignant phenotypes of bladder cancer cells T24 and 5637.

    Science.gov (United States)

    Fu, Xing; Liu, Yuchen; Zhuang, Chengle; Liu, Li; Cai, Zhiming; Huang, Weiren

    2015-05-01

    The biggest concern of using natural microRNAs for treating cancer is that they usually cause few phenotypic changes due to the divergent functions of their target genes. Based on the engineering principles of synthetic biology, we provided a standard platform for constructing artificial microRNAs that can target one or few specific genes and silence both protein-coding genes and long non-coding genes. To prove the utility of this platform, we chose MALAT1, UCA1, and c-Myc as the functional targets and used the bladder cancer cell lines T24 and 5637 as the test models. The relative expression level of the target genes was measured by qRT-PCR. Cell proliferation and migration were determined by MTT assay and wound-healing assay, respectively. Cell apoptosis was revealed by both Hoechst 33258 staining assay and ELISA assay. We found that the artificial microRNAs can effectively silence their target genes and induce anti-cancer effects in T24 and 5637 cells. These devices can inhibit proliferation, induce apoptosis, and suppress migration of the two bladder cancer cell lines. The synthetic artificial microRNAs may represent a kind of novel genetic devices for treating human bladder cancer.

  8. Lineage Reprogramming of Astroglial Cells from Different Origins into Distinct Neuronal Subtypes

    Directory of Open Access Journals (Sweden)

    Malek Chouchane

    2017-07-01

    Full Text Available Astroglial cells isolated from the rodent postnatal cerebral cortex are particularly susceptible to lineage reprogramming into neurons. However, it remains unknown whether other astroglial populations retain the same potential. Likewise, little is known about the fate of induced neurons (iNs in vivo. In this study we addressed these questions using two different astroglial populations isolated from the postnatal brain reprogrammed either with Neurogenin-2 (Neurog2 or Achaete scute homolog-1 (Ascl1. We show that cerebellum (CerebAstro and cerebral cortex astroglia (CtxAstro generates iNs with distinctive neurochemical and morphological properties. Both astroglial populations contribute iNs to the olfactory bulb following transplantation in the postnatal and adult mouse subventricular zone. However, only CtxAstro transfected with Neurog2 differentiate into pyramidal-like iNs after transplantation in the postnatal cerebral cortex. Altogether, our data indicate that the origin of the astroglial population and transcription factors used for reprogramming, as well as the region of integration, affect the fate of iNs.

  9. "Super p53" mice display retinal astroglial changes.

    Directory of Open Access Journals (Sweden)

    Juan J Salazar

    Full Text Available Tumour-suppressor genes, such as the p53 gene, produce proteins that inhibit cell division under adverse conditions, as in the case of DNA damage, radiation, hypoxia, or oxidative stress (OS. The p53 gene can arrest proliferation and trigger death by apoptosis subsequent to several factors. In astrocytes, p53 promotes cell-cycle arrest and is involved in oxidative stress-mediated astrocyte cell death. Increasingly, astrocytic p53 is proving fundamental in orchestrating neurodegenerative disease pathogenesis. In terms of ocular disease, p53 may play a role in hypoxia due to ischaemia and may be involved in the retinal response to oxidative stress (OS. We studied the influence of the p53 gene in the structural and quantitative characteristics of astrocytes in the retina. Adult mice of the C57BL/6 strain (12 months old were distributed into two groups: 1 mice with two extra copies of p53 ("super p53"; n = 6 and 2 wild-type p53 age-matched control, as the control group (WT; n = 6. Retinas from each group were immunohistochemically processed to locate the glial fibrillary acidic protein (GFAP. GFAP+ astrocytes were manually counted and the mean area occupied for one astrocyte was quantified. Retinal-astrocyte distribution followed established patterns; however, morphological changes were seen through the retinas in relation to p53 availability. The mean GFAP+ area occupied by one astrocyte in "super p53" eyes was significantly higher (p<0.05; Student's t-test than in the WT. In addition, astroglial density was significantly higher in the "super p53" retinas than in the WT ones, both in the whole-retina (p<0,01 Student's t-test and in the intermediate and peripheral concentric areas of the retina (p<0.05 Student's t-test. This fact might improve the resistance of the retinal cells against OS and its downstream signalling pathways.

  10. [Amplification of the erbb-2 (Her-2/NEU), erbb-1 (HER-1) and c-myc oncogenes is often combined with the deletion of the short arm of chromosome 17 in human carcinoma].

    Science.gov (United States)

    Imianitov, E N; Chernitsa, O I; Nikiforova, I F; Serova, O M; Sokolov, S I; Laur, O Iu; Togo, A V; Kniazev, P G

    1993-01-01

    Amplification of oncogenes erbb-2, erbb-1, c-myc and losses of heterozygosity (LOH) at chromosomes 11p (probe hras-1), 17p (probe ynz-22) and 17q (probe thh-59) were studied in 165 human tumours (60 breast, 22 ovary, 40 colorectal, 23 lung, and 20 thyroid carcinomas). The correlation (P < 0.01) between the increased copy number of mentioned oncogenes and LOH at 17p was demonstrated for tumours tested: extra copies of these oncogenes were revealed in 11 of 46 DNA specimens with LOH on ynz-22, but only in 3 of 61 without LOH. This correlation was mostly due to frequent combinations between erbb-2 amplification and 17p deletions; the incidence of increased copy number of erbb-1 and c-myc oncogenes was not high enough for final conclusions about the association of their alterations with LOH at chromosome 17p.

  11. Connexin 43-Mediated Astroglial Metabolic Networks Contribute to the Regulation of the Sleep-Wake Cycle.

    Science.gov (United States)

    Clasadonte, Jerome; Scemes, Eliana; Wang, Zhongya; Boison, Detlev; Haydon, Philip G

    2017-09-13

    Astrocytes produce and supply metabolic substrates to neurons through gap junction-mediated astroglial networks. However, the role of astroglial metabolic networks in behavior is unclear. Here, we demonstrate that perturbation of astroglial networks impairs the sleep-wake cycle. Using a conditional Cre-Lox system in mice, we show that knockout of the gap junction subunit connexin 43 in astrocytes throughout the brain causes excessive sleepiness and fragmented wakefulness during the nocturnal active phase. This astrocyte-specific genetic manipulation silenced the wake-promoting orexin neurons located in the lateral hypothalamic area (LHA) by impairing glucose and lactate trafficking through astrocytic networks. This global wakefulness instability was mimicked with viral delivery of Cre recombinase to astrocytes in the LHA and rescued by in vivo injections of lactate. Our findings propose a novel regulatory mechanism critical for maintaining normal daily cycle of wakefulness and involving astrocyte-neuron metabolic interactions. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Primary central nervous system diffuse large B-cell lymphoma shows an activated B-cell-like phenotype with co-expression of C-MYC, BCL-2, and BCL-6.

    Science.gov (United States)

    Li, Xiaomei; Huang, Ying; Bi, Chengfeng; Yuan, Ji; He, Hong; Zhang, Hong; Yu, QiuBo; Fu, Kai; Li, Dan

    2017-06-01

    Diffuse large B-cell lymphoma (DLBCL) is the most common non-Hodgkin lymphoma, whose main prognostic factor is closely related to germinal center B-cell-like subtype (GCB- DLBCL) or activated B-cell-like type (non-GCB-DLBCL). The most common type of primary central nervous system lymphoma is diffuse large B-cell type with poor prognosis and the reason is unclear. This study aims to stratify primary central nervous system diffuse large B-cell lymphoma (PCNS-DLBCL) according to the cell-of-origin (COO) and to investigate the multiple proteins expression of C-MYC, BCL-6, BCL-2, TP53, further to elucidate the reason why primary central nervous system diffuse large B-cell lymphoma possesses a poor clinical outcome as well. Nineteen cases of primary central nervous system DLBCL were stratified according to immunostaining algorithms of Hans, Choi and Meyer (Tally) and we investigated the multiple proteins expression of C-MYC, BCL-6, BCL-2, TP53. The Epstein-Barr virus and Borna disease virus infection were also detected. Among nineteen cases, most (15-17 cases) were assigned to the activated B-cell-like subtype, highly expression of C-MYC (15 cases, 78.9%), BCL-2 (10 cases, 52.6%), BCL-6 (15 cases, 78.9%). Unfortunately, two cases were positive for PD-L1 while PD-L2 was not expressed in any case. Two cases infected with BDV but no one infected with EBV. In conclusion, most primary central nervous system DLBCLs show an activated B-cell-like subtype characteristic and have multiple expressions of C-MYC, BCL-2, BCL-6 protein, these features might be significant factor to predict the outcome and guide treatment of PCNS-DLBCLs. Copyright © 2017 Elsevier GmbH. All rights reserved.

  13. Forced expression of miR-143 represses ERK5/c-Myc and p68/p72 signaling in concert with miR-145 in gut tumors of Apc(Min) mice.

    Science.gov (United States)

    Takaoka, Yuji; Shimizu, Yuko; Hasegawa, Hitoki; Ouchi, Yasuo; Qiao, Shanlou; Nagahara, Miki; Ichihara, Masatoshi; Lee, Jiing-Dwan; Adachi, Koichi; Hamaguchi, Michinari; Iwamoto, Takashi

    2012-01-01

    Recently, miR-143 and miR-145 have been shown to belong to a subset of microRNAs whose expression is controlled by a complex of a tumor suppressor p53 and DEAD-box RNA helicase subunits p68/p72. While accumulating studies have acknowledged that both miRNAs function as tumor suppressors and are similarly regulated, evidence of their coordinated action against tumorigenesis has been poorly presented. Herein, we establish transgenic mice that express miR-143 under the control of the CAG regulatory unit. When crossbred with Apc(Min/+) mice, the development of tumors in the small intestines is significantly attenuated. In the transgenic small intestine tumors, the endogenous miR-145 is also enhanced and the expression of c-Myc and p68/p72, both of which have been reported to be pivotal for gut tumor development, is suppressed, corresponding to the downregulation of ERK5. We demonstrate that the combination of miR-143 and miR-145 inhibits the expression of c-Myc in human colon cancer cells, whereas miR-145 retards that of p72. Moreover, we show the possibilities that miR-145 modulates p72 expression through its 3' untranslated region and that c-Myc downregulation is involved in both p68 suppression and miR-145 induction. These findings suggest that forced expression of miR-143, probably interacting with endogenous miR-145, inhibits ERK5/c-Myc and p68/p72/β-catenin signaling and hampers small intestine tumor development in Apc(Min/+) mice. This unique cascade, in turn, may prevent overproduction of a subset of tumor suppressive miRNAs by repressing their own modulators, p68/p72.

  14. Forced expression of miR-143 represses ERK5/c-Myc and p68/p72 signaling in concert with miR-145 in gut tumors of Apc(Min mice.

    Directory of Open Access Journals (Sweden)

    Yuji Takaoka

    Full Text Available Recently, miR-143 and miR-145 have been shown to belong to a subset of microRNAs whose expression is controlled by a complex of a tumor suppressor p53 and DEAD-box RNA helicase subunits p68/p72. While accumulating studies have acknowledged that both miRNAs function as tumor suppressors and are similarly regulated, evidence of their coordinated action against tumorigenesis has been poorly presented. Herein, we establish transgenic mice that express miR-143 under the control of the CAG regulatory unit. When crossbred with Apc(Min/+ mice, the development of tumors in the small intestines is significantly attenuated. In the transgenic small intestine tumors, the endogenous miR-145 is also enhanced and the expression of c-Myc and p68/p72, both of which have been reported to be pivotal for gut tumor development, is suppressed, corresponding to the downregulation of ERK5. We demonstrate that the combination of miR-143 and miR-145 inhibits the expression of c-Myc in human colon cancer cells, whereas miR-145 retards that of p72. Moreover, we show the possibilities that miR-145 modulates p72 expression through its 3' untranslated region and that c-Myc downregulation is involved in both p68 suppression and miR-145 induction. These findings suggest that forced expression of miR-143, probably interacting with endogenous miR-145, inhibits ERK5/c-Myc and p68/p72/β-catenin signaling and hampers small intestine tumor development in Apc(Min/+ mice. This unique cascade, in turn, may prevent overproduction of a subset of tumor suppressive miRNAs by repressing their own modulators, p68/p72.

  15. miR-196b targets c-myc and Bcl-2 expression, inhibits proliferation and induces apoptosis in endometriotic stromal cells.

    Science.gov (United States)

    Abe, Wakana; Nasu, Kaei; Nakada, Chisato; Kawano, Yukie; Moriyama, Masatsugu; Narahara, Hisashi

    2013-03-01

    What is the global expression pattern of microRNAs (miRNAs) in endometriotic stromal cells and is miR-196b involved in the pathogenesis of endometriosis? Several miRNAs are aberrantly expressed in endometriotic cyst stromal cells (ECSCs), including miR-196b whose expression is repressed in endometriotic stromal cells. Although, histologically, endometriotic tissues and normal proliferative endometrium are similar, a number of distinct molecular differences have been reported to date. The anti-apoptotic and excessive proliferative properties of endometriotic cells are considered to be involved in the development and progression of endometriosis. ECSCs and normal endometrial stromal cells (NESCs) were isolated from ovarian endometriotic tissues and eutopic endometrial tissues, respectively and compared. Aberrantly expressed miRNAs in ECSCs were identified by a global miRNA microarray technique. The roles of miR-196b in ECSC proliferation, apoptosis, and c-myc and B-cell lymphoma/leukemia (Bcl)-2 mRNA expression were investigated with precursor hsa-miR-196b transfection. The methylation status of the miR-196b gene in ECSCs and the effect of a DNA demethylating agent on miR-196b expression were also examined. miRNA microarray analysis identified eight down-regulated miRNAs (including miR-196b) and four up-regulated miRNAs in ECSCs. Compulsory expression of miR-196b directed the inhibition of proliferation and the induction of apoptosis in ECSCs. miR-196b was found to suppress c-myc and Bcl-2 mRNA expression in ECSCs, and there was a significant correlation between miR-196b and HOXA10 expression in ECSCs and NESCs. The miR-196b gene was hypermethylated in ECSCs when compared with NESCs, and the treatment with a DNA demethylating agent restored the expression of miR-196b in ECSCs. miRNA expression profiles were investigated only in the stromal component of ectopic and eutopic endometrium samples. In addition to miR-196b, the roles of other miRNAs aberrantly expressed in

  16. Enforced expression of the c-myc oncogene inhibits cell differentiation by precluding entry into a distinct predifferentiation state in G/sub 0//G/sub 1/

    Energy Technology Data Exchange (ETDEWEB)

    Freytag, S.O.

    1988-04-01

    A broad base of data has implicated a role for the c-myc proto-oncogene in the control of the cell cycle and cell differentiation. To further define the role of myc in these processes, the authors examined the effect of enforced myc expression on several events that are thought to be important steps leading to the terminally differentiated state: (i) the ability to arrest growth in G/sub 0//G/sub 1/, (ii) the ability to replicate the genome upon initiation of the differentiation program, and (iii) the ability to loose responsiveness to mitogens and withdraw from the cell cycle. 3T3-L1 preadipocyte cell lines expressing various levels of myc mRNA were established by transfection with a recombinant myc gene under the transcriptional control of the Rous sarcoma virus (RSV) promoter. Cells that expressed high constitutive levels of pRSV myc mRNA arrested in G/sub 0//G/sub 1/ at densities similar to those of normal cells at confluence. Upon initiation of the differentiation program, such cells traversed the cell cycle with kinetics similar to those of normal cells and subsequently arrested in G/sub 0//G/sub 1/. Thus, enforced expression of myc had no effect on the ability of cells to arrest growth in G/sub 0//G/sub 1/ or to replicate the genome upon initiation of the differentiation program. Cells were then tested for their ability to reenter the cell cycle upon exposure to high concentrations of serum and for their capacity to differentiate. In contrast to normal cells, cells expressing high constitutive levels of myc RNA reentered the cell cycle when challenged with 30% serum and failed to terminally differentiate.

  17. 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...

  18. Functional variability in butyrylcholinesterase activity regulates intrathecal cytokine and astroglial biomarker profiles in patients with Alzheimer's disease

    DEFF Research Database (Denmark)

    Darreh-Shori, Taher; Vijayaraghavan, Swetha; Aeinehband, Shahin

    2013-01-01

    with noncarriers. A high level of CSF BuChE enzymatic phenotype also significantly correlated with higher CSF levels of astroglial markers and several factors of the innate complement system, but lower levels of proinflammatory cytokines. These individuals also displayed beneficial paraclinical and clinical...... and that this might be of clinical relevance. The dissociation between astroglial markers and inflammatory cytokines indicates that a proper activation and maintenance of astroglial function is a beneficial response, rather than a disease-driving mechanism. Further studies are needed to explore the therapeutic...

  19. A mouse strain defective in both T cells and NK cells has enhanced sensitivity to tumor induction by plasmid DNA expressing both activated H-Ras and c-Myc.

    Directory of Open Access Journals (Sweden)

    Li Sheng-Fowler

    Full Text Available As part of safety studies to evaluate the risk of residual cellular DNA in vaccines manufactured in tumorigenic cells, we have been developing in vivo assays to detect and quantify the oncogenic activity of DNA. We generated a plasmid expressing both an activated human H-ras gene and murine c-myc gene and showed that 1 µg of this plasmid, pMSV-T24-H-ras/MSV-c-myc, was capable of inducing tumors in newborn NIH Swiss mice. However, to be able to detect the oncogenicity of dominant activated oncogenes in cellular DNA, a more sensitive system was needed. In this paper, we demonstrate that the newborn CD3 epsilon transgenic mouse, which is defective in both T-cell and NK-cell functions, can detect the oncogenic activity of 25 ng of the circular form of pMSV-T24-H-ras/MSV-c-myc. When this plasmid was inoculated as linear DNA, amounts of DNA as low as 800 pg were capable of inducing tumors. Animals were found that had multiple tumors, and these tumors were independent and likely clonal. These results demonstrate that the newborn CD3 epsilon mouse is highly sensitive for the detection of oncogenic activity of DNA. To determine whether it can detect the oncogenic activity of cellular DNA derived from four human tumor-cell lines (HeLa, A549, HT-1080, and CEM, DNA (100 µg was inoculated into newborn CD3 epsilon mice both in the presence of 1 µg of linear pMSV-T24-H-ras/MSV-c-myc as positive control and in its absence. While tumors were induced in 100% of mice with the positive-control plasmid, no tumors were induced in mice receiving any of the tumor DNAs alone. These results demonstrate that detection of oncogenes in cellular DNA derived from four human tumor-derived cell lines in this mouse system was not possible; the results also show the importance of including a positive-control plasmid to detect inhibitory effects of the cellular DNA.

  20. 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.

  1. Ethanol and diolein stimulate PKC (protein kinase C) translocation in astroglial cells

    Energy Technology Data Exchange (ETDEWEB)

    Skwish, S. (State Univ. of New York, Albany (USA)); Shain, W. (State Univ. of New York, Albany (USA) New York State Department of Health, Albany (USA))

    1990-01-01

    Ethanol exposure stimulates taurine release from astroglial cells. To determine if ethanol mediates this release using protein kinase C (PKC), PKC activity was measured using LRM55 astroglial cells. When ethanol or diolein was applied to cells for 30 seconds, PKC activity was observed to decrease in the cytosol and increase in the membrane fraction of the cell while the whole cell activity remained unchanged. The membrane-associated activity increased by almost 100%. When ethanol and diolein were applied simultaneously, membrane-associated activity increased to become 3-5 times greater than when either PKC activator was applied alone. These changes in PKC activity parallel changes in taurine release observed when cells are exposed to ethanol and the PKC activator diolein. Ethanol-stimulated release may be associated with the translocation of PKC activity from the cytosol to the membrane.

  2. Rising stars: modulation of brain functions by astroglial type-1 cannabinoid receptors.

    Science.gov (United States)

    Metna-Laurent, Mathilde; Marsicano, Giovanni

    2015-03-01

    The type-1-cannabinoid (CB1 ) receptor is amongst the most widely expressed G protein-coupled receptors in the brain. In few decades, CB1 receptors have been shown to regulate a large array of functions from brain cell development and survival to complex cognitive processes. Understanding the cellular mechanisms underlying these functions of CB1 is complex due to the heterogeneity of the brain cell types on which the receptor is expressed. Although the large majority of CB1 receptors act on neurons, early studies pointed to a direct control of CB1 receptors over astroglial functions including brain energy supply and neuroprotection. In line with the growing concept of the tripartite synapse highlighting astrocytes as direct players in synaptic plasticity, astroglial CB1 receptor signaling recently emerged as the mediator of several forms of synaptic plasticity associated to important cognitive functions. Here, we shortly review the current knowledge on CB1 receptor-mediated astroglial functions. This functional spectrum is large and most of the mechanisms by which CB1 receptors control astrocytes, as well as their consequences in vivo, are still unknown, requiring innovative approaches to improve this new cannabinoid research field. © 2014 Wiley Periodicals, Inc.

  3. IS THE AMPLIFICATION OF c-MYC, MLL AND RUNX1 GENES IN AML AND MDS PATIENTS WITH TRISOMY 8, 11 AND 21 A FACTOR FOR A CLONAL EVOLUTION IN THEIR KARYOTYPE?

    Science.gov (United States)

    Angelova, S; Spassov, B; Nikolova, V; Christov, I; Tzvetkov, N; Simeonova, M

    2015-01-01

    The aim of our study was 1) to define if the amplification of c-MYC, MLL and RUNX1 genes is related to the progressive changes of the karyotype in patients with AML and MDS with trisomy 8, 11 and 21 (+8, +11 and +21) in bone marrow and 2) can that amplification be accepted as part of the clonal evolution (CE). Karyotype analysis was performed in 179 patients with AML or MDS with the different chromosomal aberrations (CA) aged 16-81. The findings were distributed as follow: initiating balanced CA (n = 60), aneuploidia (n = 55), unbalanced CA (n = 64). Amplification of c-MYC, MLL and RUNX1 genes by means of fluorescence in situ hybridization (FISH) was found in 35% (7 out of 20) of AML and MDS patients with +8, +11 u +21 as single CA in their karyotype; in 63.6% of pts (7 out of 11)--with additional numerical or structural CA and in 75% (9 out of 12)--with complex karyotype. We assume that the amplification of the respective chromosomal regions in patients with +8, +11 and +21 is related to CE. Considering the amplification as a factor of CE, we established 3 patterns of karyotype development depending on the type of the initiating CA in it. Significant statistical differences were found between the three patterns regarding the karyotype distribution in the different stages of progression (p < 0.001).

  4. Sodium arsenite induces ROS generation, DNA oxidative damage, HO-1 and c-Myc proteins, NF-kappaB activation and cell proliferation in human breast cancer MCF-7 cells.

    Science.gov (United States)

    Ruiz-Ramos, Ruben; Lopez-Carrillo, Lizbeth; Rios-Perez, Alfonso D; De Vizcaya-Ruíz, Andrea; Cebrian, Mariano E

    2009-03-31

    Epidemiological evidence has associated exposure to arsenic (As) in drinking water with an increased incidence of human cancers in the skin, bladder, liver, kidney and lung. Sodium arsenite mimics the effects of estradiol and induces cell proliferation in the estrogen responsive breast cancer cell line MCF-7. Therefore, our aim was to further explore the ability of sodium arsenite to induce MCF-7 epithelial breast cell proliferation and some of its underlying mechanisms by studying ROS production, c-Myc and HO-1 protein levels, 8-OHdG formation and NF-kappaB activation. Low arsenite concentrations (0.5-5 microM) induced ROS production and ROS-related depolarization of the mitochondrial membrane suggesting that mitochondria played an important role in the oxidative effects of As. ROS-mediated DNA damage as measured by the presence of 8-OHdG DNA-adducts in their nuclei, IkappaB phosphorylation, NF-kappaB activation and increases in c-Myc and HO-1 protein levels were also observed, suggesting that these factors play a relevant role in the arsenite induced MCF-7 cell recruitment into the S-phase of the cell cycle and cell proliferation observed. In conclusion, arsenite activates several pathways involved in MCF-7 cell proliferation suggesting that arsenite exposure may pose a risk for breast cancer in human exposed populations notwithstanding that most studies to date have not yet implicated this metalloid as a cofactor in the etiology of this disease.

  5. Proliferation, cell cycle exit, and onset of terminal differentiation in cultured keratinocytes: pre-programmed pathways in control of C-Myc and Notch1 prevail over extracellular calcium signals.

    Science.gov (United States)

    Kolly, Carine; Suter, Maja M; Müller, Eliane J

    2005-05-01

    So far it was reported that a switch from low to high extracellular calcium induces growth arrest and terminal differentiation in cultured human and mouse keratinocytes. We had observed that both canine and mouse keratinocytes proliferate in high (1.8 mM, respectively, 1.2 mM) or low (0.09 and 0.06 mM) calcium-containing medium. In-depth analysis of this phenomenon revealed, as reported here, that the switch between proliferation and terminal differentiation occurred irrespective of calcium conditions when the canine and murine keratinocytes reach confluency. The "confluency switch" coincided with transcriptional upregulation of cell cycle inhibitors p21(WAF1) and p27(KIP1) as well as proteins marking onset of terminal differentiation. It was further accompanied by downregulation and nuclear clearance of c-Myc, and conversely activation of Notch1, which are shown to be critical determinants of this process. Together, this study demonstrates that even in the absence of and similar to their in vivo environment, cultured canine and mouse keratinocytes follow a pre-defined differentiation program. This program is in control of c-Myc and Notch1 and does not require complementary signals for onset of terminal differentiation except those given by cell-cell contact. Once triggered, completion of the terminal differentiation process depends on elevated extracellular calcium to stabilize intercellular junctions and components of the cornified envelope.

  6. Induction of interleukin-8 by Naegleria fowleri lysates requires activation of extracellular signal-regulated kinase in human astroglial cells.

    Science.gov (United States)

    Kim, Jong-Hyun; Sohn, Hae-Jin; Lee, Sang-Hee; Kwon, Daeho; Shin, Ho-Joon

    2012-08-01

    Naegleria fowleri is a pathogenic free-living amoeba which causes primary amoebic meningoencephalitis in humans and experimental animals. To investigate the mechanisms of such inflammatory diseases, potential chemokine gene activation in human astroglial cells was investigated following treatment with N. fowleri lysates. We demonstrated that N. fowleri are potent inducers for the expression of interleukin-8 (IL-8) genes in human astroglial cells which was preceded by activation of extracellular signal-regulated kinase (ERK). In addition, N. fowleri lysates induces the DNA binding activity of activator protein-1 (AP-1), an important transcription factor for IL-8 induction. The specific mitogen-activated protein kinase kinase/ERK inhibitor, U0126, blocks N. fowleri-mediated AP-1 activation and subsequent IL-8 induction. N. fowleri-induced IL-8 expression requires activation of ERK in human astroglial cells. These findings indicate that treatment of N. fowleri on human astroglial cells leads to the activation of AP-1 and subsequent expression of IL-8 which are dependent on ERK activation. These results may help understand the N. fowleri-mediated upregulation of chemokine and cytokine expression in the astroglial cells.

  7. Decreased astroglial cell adhesion and proliferation on zinc oxide nanoparticle polyurethane composites.

    Science.gov (United States)

    Seil, Justin T; Webster, Thomas J

    2008-01-01

    Nanomaterials offer a number of properties that are of interest to the field of neural tissue engineering. Specifically, materials that exhibit nanoscale surface dimensions have been shown to promote neuron function while simultaneously minimizing the activity of cells such as astrocytes that inhibit central nervous system regeneration. Studies demonstrating enhanced neural tissue regeneration in electrical fields through the use of conductive materials have led to interest in piezoelectric materials (or those materials which generate a transient electrical potential when mechanically deformed) such as zinc oxide (ZnO). It has been speculated that ZnO nanoparticles possess increased piezoelectric properties over ZnO micron particles. Due to this promise in neural applications, the objective of the present in vitro study was, for the first time, to assess the activity of astroglial cells on ZnO nanoparticle polymer composites. ZnO nanoparticles embedded in polyurethane were analyzed via scanning electron microscopy to evaluate nanoscale surface features of the composites. The surface chemistry was characterized via X-ray photoelectron spectroscopy. Astroglial cell response was evaluated based on cell adhesion and proliferation. Astrocyte adhesion was significantly reduced on ZnO nanoparticle/polyurethane (PU) composites with a weight ratio of 50:50 (PU:ZnO) wt.%, 75:25 (PU:ZnO) wt.%, and 90:10 (PU:ZnO) wt.% in comparison to pure PU. The successful production of ZnO nanoparticle composite scaffolds suitable for decreasing astroglial cell density demonstrates their potential as a nerve guidance channel material with greater efficiency than what may be available today.

  8. Direct short-term cytotoxic effects of BIBR 1532 on acute promyelocytic leukemia cells through induction of p21 coupled with downregulation of c-Myc and hTERT transcription.

    Science.gov (United States)

    Bashash, D; Ghaffari, S H; Zaker, F; Hezave, K; Kazerani, M; Ghavamzadeh, A; Alimoghaddam, K; Mosavi, S A; Gharehbaghian, A; Vossough, P

    2012-01-01

    Acute promyelocytic leukemia (APL) is characterized by specific t(15;17), distinct morphologic picture, and clinical coagulopathy that contribute to the morbidity and mortality of the disease. This study aims to investigate the effects of antitelomerase compound BIBR1532 on APL cells (NB4). BIBR 1532 exerts a direct short-term growth suppressive effect in a concentration-dependent manner probably through downregulation of c-Myc and hTERT expression. Our results also suggest that induction of p21 and subsequent disturbance of Bax/Bcl-2 balanced ratio as well as decreased telomerase activity may be rational mechanisms for the potent/direct short-term cytotoxicity of high doses of BIBR1532 against NB4 cells.

  9. Cooperation between the polyomavirus Middle-T-antigen gene and the human c-myc oncogene in a rat thyroid epithelial differentiated cell line: Model of in vitro progression

    Energy Technology Data Exchange (ETDEWEB)

    Berlingieri, M.T.; Portella, G.; Grieco, M.; Santoro, M.; Fusco, A.

    1988-05-01

    Two rat thyroid epithelial differentiated cell lines, PC CI 3 and PC myc, were infected with the polyoma murine leukemia virus (PyMLV) carrying the Middle-T-antigen gene of polyomavirus. After infection, both cell lines acquired the typical markers of neoplastic transformation; however, the PC myc cells showed a greater malignant phenotype. Furthermore, the thyroid differentiated functions were completely suppressed in PC myc cells transformed by PyMLV, whereas they were, at least partially, retained in PC CI 3 cells transformed by PyMLV, and in particular, thyroglobulin synthesis and secretion were not affected at all. Since no differences in the expression of the middle-T-antigen gene were observed in the two PyMLV-transformed cell lines, the different properties shown by these two infected cell lines must be ascribed to the expression of the c-myc oncogene.

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

    Science.gov (United States)

    von Bueren, André O.; Ćwiek, Paulina; Rehrauer, Hubert; Djonov, Valentin; Anderle, Pascale; Arcaro, Alexandre

    2015-01-01

    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. PMID:25915540

  11. 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.

  12. Cannabinoids prevent the amyloid β-induced activation of astroglial hemichannels: A neuroprotective mechanism.

    Science.gov (United States)

    Gajardo-Gómez, Rosario; Labra, Valeria C; Maturana, Carola J; Shoji, Kenji F; Santibañez, Cristian A; Sáez, Juan C; Giaume, Christian; Orellana, Juan A

    2017-01-01

    The mechanisms involved in Alzheimer's disease are not completely understood and how astrocytes and their gliotransmission contribute to this neurodegenerative disease remains to be fully elucidated. Previous studies have shown that amyloid-β peptide (Aβ) induces neuronal death by a mechanism that involves the excitotoxic release of ATP and glutamate associated to astroglial hemichannel opening. We have demonstrated that synthetic and endogenous cannabinoids (CBs) reduce the opening of astrocyte Cx43 hemichannels evoked by activated microglia or inflammatory mediators. Nevertheless, whether CBs could prevent the astroglial hemichannel-dependent death of neurons evoked by Aβ is unknown. Astrocytes as well as acute hippocampal slices were treated with the active fragment of Aβ alone or in combination with the following CBs: WIN, 2-AG, or methanandamide (Meth). Hemichannel activity was monitored by single channel recordings and by time-lapse ethidium uptake while neuronal death was assessed by Fluoro-Jade C staining. We report that CBs fully prevented the hemichannel activity and inflammatory profile evoked by Aβ in astrocytes. Moreover, CBs fully abolished the Aβ-induced release of excitotoxic glutamate and ATP associated to astrocyte Cx43 hemichannel activity, as well as neuronal damage in hippocampal slices exposed to Aβ. Consequently, this work opens novel avenues for alternative treatments that target astrocytes to maintain neuronal function and survival during AD. GLIA 2016 GLIA 2017;65:122-137. © 2016 Wiley Periodicals, Inc.

  13. Mdivi-1 inhibits astrocyte activation and astroglial scar formation and enhances axonal regeneration after spinal cord injury in rats

    Directory of Open Access Journals (Sweden)

    gang li

    2016-10-01

    Full Text Available After spinal cord injury (SCI, astrocytes become hypertrophic and proliferative, forming a dense network of astroglial processes at the site of the lesion. This constitutes a physical and biochemical barrier to axonal regeneration. Mitochondrial fission regulates cell cycle progression; inhibiting the cell cycle of astrocytes can reduce expression levels of axon growth-inhibitory molecules as well as astroglial scar formation after SCI. We therefore investigated how an inhibitor of mitochondrial fission, Mdivi-1, would affect astrocyte proliferation, astroglial scar formation, and axonal regeneration following SCI in rats. Western blot and immunofluorescent double-labeling showed that Mdivi-1 markedly reduced the expression of the astrocyte marker glial fibrillary acidic protein (GFAP, and a cell proliferation marker, proliferating cell nuclear antigen, in astrocytes 3 days after SCI. Moreover, Mdivi-1 decreased the expression of GFAP and neurocan, a chondroitin sulfate proteoglycan. Notably, immunofluorescent labeling and Nissl staining showed that Mdivi-1 elevated the production of growth-associated protein-43 and increased neuronal survival at 4 weeks after SCI. Finally, hematoxylin-eosin staining and behavioral evaluation of motor function indicated that Mdivi-1 also reduced cavity formation and improved motor function 4 weeks after SCI. Our results confirm that Mdivi-1 promotes motor function after SCI, and indicate that inhibiting mitochondrial fission using Mdivi-1 can inhibit astrocyte activation and astroglial scar formation and contribute to axonal regeneration after SCI in rats.

  14. Mannitol induces selective astroglial death in the CA1 region of the rat hippocampus following status epilepticus

    Science.gov (United States)

    Ko, Ah-Reum; Kang, Tae-Cheon

    2015-01-01

    In the present study, we addressed the question of whether treatment with mannitol, an osmotic diuretic, affects astrogliovascular responses to status epilepticus (SE). In saline-treated animals, astrocytes exhibited reactive astrogliosis in the CA1-3 regions 2-4 days after SE. In the mannitol-treated animals, a large astroglial empty zone was observed in the CA1 region 2 days after SE. This astroglial loss was unrelated to vasogenic edema formation. There was no difference in SE-induced neuronal loss between saline- and mannitol-treated animals. Furthermore, mannitol treatment did not affect astroglial loss and vasogenic edema formation in the dentate gyrus and the piriform cortex. These findings suggest that mannitol treatment induces selective astroglial loss in the CA1 region independent of vasogenic edema formation following SE. These findings support the hypothesis that the susceptibility of astrocytes to SE is most likely due to the distinctive heterogeneity of astrocytes independent of hemodynamics. [BMB Reports 2015; 48(9): 507-512] PMID:25703536

  15. Effects of atypical (risperidone) and typical (haloperidol) antipsychotic agents on astroglial functions.

    Science.gov (United States)

    Quincozes-Santos, André; Bobermin, Larissa Daniele; Tonial, Rafaela Pestana Leques; Bambini-Junior, Victorio; Riesgo, Rudimar; Gottfried, Carmem

    2010-09-01

    Although classical and atypical antipsychotics may have different neurotoxic effects, their underlying mechanisms remain to be elucidated, especially regarding neuroglial function. In the present study, we compared the atypical antipsychotic risperidone (0.01-10 μM) with the typical antipsychotic haloperidol (0.01-10 μM) regarding different aspects such as glutamate uptake, glutamine synthetase (GS) activity, glutathione (GSH) content, and intracellular reactive oxygen species (ROS) production in C6 astroglial cells. Risperidone significantly increased glutamate uptake (up to 27%), GS activity (14%), and GSH content (up to 17%). In contrast, haloperidol was not able to change any of these glial functions. However, at concentration of 10 μM, haloperidol increased (12%) ROS production. Our data contribute to the clarification of different hypothesis concerning the putative neural responses after stimulus with different antipsychotics, and may establish important insights about how brain rewiring could be enhanced.

  16. Loss of neuron-astroglial interaction rapidly induces protective CNTF expression after stroke in mice

    Science.gov (United States)

    Kang, Seong Su; Keasey, Matthew P.; Cai, Jun; Hagg, Theo

    2012-01-01

    Ciliary neurotrophic factor (CNTF) is a potent neural cytokine with very low expression in the CNS, predominantly by astrocytes. CNTF increases rapidly and greatly following traumatic or ischemic injury. Understanding the underlying mechanisms would help to design pharmacological treatments to increase endogenous CNTF levels for neuroprotection. Here, we show that astroglial CNTF expression in the adult mouse striatum is increased two-fold within 1 hour and increases up to >30 fold over two weeks following a focal stroke caused by a transient middle cerebral artery occlusion (MCAO). Selective neuronal loss caused by intrastriatal injection of quinolinic acid resulted in a comparable increase. Co-cultured neurons reduced CNTF expression in astrocytes which was prevented by light trypsinization. RGD blocking peptides induced CNTF expression which was dependent on transcription. Astroglial CNTF expression was not affected by diffusible neuronal molecules or by neurotransmitters. The transient ischemia does not seem to directly increase CNTF, as intrastriatal injection of an ischemic solution or exposure of naive mice or cultured cells to severe hypoxia had minimal effects. Inflammatory mechanisms were probably also not involved, as intrastriatal injection of pro-inflammatory cytokines (IFNγ, IL6) in naive mice had no or small effects, and anti-inflammatory treatments did not diminish the increase in CNTF after MCAO. CNTF−/− mice had more extensive tissue loss and similar astrocyte activation after MCAO than their wildtype littermates. These data suggest that contact-mediated integrin signaling between neurons and astrocytes normally represses CNTF expression and that neuronal dysfunction causes a rapid protective response by the CNS. PMID:22764235

  17. Comparative analysis of the EGFR, HER2, c-MYC, and MET variations in colorectal cancer determined by three different measures: gene copy number gain, amplification status and the 2013 ASCO/CAP guideline criterion for HER2 testing of breast cancer.

    Science.gov (United States)

    Kwak, Yoonjin; Yun, Sumi; Nam, Soo Kyung; Seo, An Na; Lee, Kyu Sang; Shin, Eun; Oh, Heung-Kwon; Kim, Duck Woo; Kang, Sung Bum; Kim, Woo Ho; Lee, Hye Seung

    2017-08-01

    The purpose of this study was to explore gene copy number (GCN) variation of EGFR, HER2, c-MYC, and MET in patients with primary colorectal cancer (CRC). Dual-colour silver-enhanced in situ hybridization was performed in tissue samples of 334 primary CRC patients. The amplification status (GCN ratio ≥2) and GCN gain (average GCN ≥4) data for the EGFR, HER2, c-MYC and MET genes were obtained. GCN variation was also assessed by the criterion of the 2013 ASCO/CAP guidelines for HER2 testing. Amplification of EGFR, HER2, c-MYC and MET was detected in 8 (2.4%), 20 (6.0%), 29 (8.7%), and 14 (4.2%) patients, respectively. Of 66 patients with at least one amplified gene, five exhibited co-amplification of genes studied (HER2-MET co-amplification: two patients; HER2-c-MYC co-amplification: two patients; EGFR-c-MYC co-amplification: one patient). There were 109 patients with GCN gains of one or more genes (EGFR: 11/334, HER2: 29/334, c-MYC; 60/334, MET: 48/334) and 32.1% (35/109) had multiple GCN gains. When each GCN was assessed by the criterion of the ASCO/CAP 2013 guideline for HER2 testing, 116 people showed positive or equivocal results for one or more genes. The cumulative amplification status had no association with patients' outcome. However, the cumulative results of the GCN gain and GCN status determined according to the ASCO/CAP guideline had a significant prognostic correlation in the univariate analysis (P values of 0.006 and 0.022, respectively). In the multivariate analysis, GCN gain and GCN status were independent prognostic factors (P values of 0.010 and 0.017, respectively). In this study, we evaluated GCN variation of four genes in a large sample of Korean CRC patients. The amplification status was not related to patient outcome. However, the GCN gain and GCN status according to the ASCO/CAP 2013 guideline were independent prognostic factors.

  18. 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...

  19. PRIMA-1 induces caspase-mediated apoptosis in acute promyelocytic leukemia NB4 cells by inhibition of nuclear factor-κB and downregulation of Bcl-2, XIAP, and c-Myc.

    Science.gov (United States)

    Farhadi, Elham; Safa, Majid; Sharifi, Ali M; Bashash, Davood

    2017-01-01

    Restoration of p53 function triggers cell death and eliminates tumors in vivo. Identification of p53-reactivating small molecules such as PRIMA-1 holds promise for effective new anticancer therapies. Here, we investigated the effects of small molecule PRIMA-1 on cell viability and expression of p53-regulated genes and proteins in the acute promyelocytic leukemia-derived NB4 cell line. Our results showed that PRIMA-1 had antileukemic properties in acute promyelocytic leukemia-derived NB4 cells. PRIMA-1-triggered apoptosis in a dose-dependent and time-dependent manner as indicated by the MTT assay and annexin-V staining. Apoptosis induction by PRIMA-1 was associated with caspase-9, caspase-7 activation and PARP cleavage. p21 protein expression was increased after PRIMA-1 treatment and real-time PCR analysis of proapoptotic p53 target genes indicated upregulation of Bax and Noxa. Western blot analysis showed that IκBα phosphorylation and its degradation were inhibited by PRIMA-1. Moreover, protein expression of nuclear factor-κB-regulated antiapoptotic (Bcl-2 and XIAP) and proliferative (c-Myc) gene products was decreased. Importantly, PRIMA-1 did not show any significant apoptotic effect in normal human peripheral blood mononuclear cells. These in-vitro studies imply that p53 reactivation by small compounds may become a novel anticancer therapy in acute promyelocytic leukemia.

  20. CAPER is vital for energy and redox homeostasis by integrating glucose-induced mitochondrial functions via ERR-α-Gabpa and stress-induced adaptive responses via NF-κB-cMYC.

    Directory of Open Access Journals (Sweden)

    Yun Kyoung Kang

    2015-04-01

    Full Text Available Ever since we developed mitochondria to generate ATP, eukaryotes required intimate mito-nuclear communication. In addition, since reactive oxygen species are a cost of mitochondrial oxidative phosphorylation, this demands safeguards as protection from these harmful byproducts. Here we identified a critical transcriptional integrator which eukaryotes share to orchestrate both nutrient-induced mitochondrial energy metabolism and stress-induced nuclear responses, thereby maintaining carbon-nitrogen balance, and preserving life span and reproductive capacity. Inhibition of nutrient-induced expression of CAPER arrests nutrient-dependent cell proliferation and ATP generation and induces autophagy-mediated vacuolization. Nutrient signaling to CAPER induces mitochondrial transcription and glucose-dependent mitochondrial respiration via coactivation of nuclear receptor ERR-α-mediated Gabpa transcription. CAPER is also a coactivator for NF-κB that directly regulates c-Myc to coordinate nuclear transcriptome responses to mitochondrial stress. Finally, CAPER is responsible for anaplerotic carbon flux into TCA cycles from glycolysis, amino acids and fatty acids in order to maintain cellular energy metabolism to counter mitochondrial stress. Collectively, our studies reveal CAPER as an evolutionarily conserved 'master' regulatory mechanism by which eukaryotic cells control vital homeostasis for both ATP and antioxidants via CAPER-dependent coordinated control of nuclear and mitochondrial transcriptomic programs and their metabolisms. These CAPER dependent bioenergetic programs are highly conserved, as we demonstrated that they are essential to preserving life span and reproductive capacity in human cells-and even in C. elegans.

  1. [Complex characteristics of the alterations of oncogenes HER-2/ERBB-2, HER-1/ERBB-1, HRAS-1, C-MYC and antioncogenes p53, RB1, as well as deletions of loci of chromosome 17 in colon carcinoma].

    Science.gov (United States)

    Kniazev, P G; Imianitov, E N; Chernitsa, O I; Nikiforova, I F; Babenko, V I; Bruderliaĭn, S; Plutalo, O V; Kuz'min, A I; Kaboev, O K; Berlin, Iu A

    1992-01-01

    Abnormalities of some oncogenes, antioncogenes and losses of heterozygosity (LOH) of chromosome 11p, 17p, and 17q in colorectal carcinomas (CC) was studied. Amplification of ERBB-1/HER-1 oncogene was detected in 2 of 56 cases; ERBB-2/HER-2- in 4 of 62. There was a lack of evidence for C-MYC oncogene amplification (67 cases). LOH of chromosome 11p (HRAS-1 probe) was found in 2 of 37 informative (heterozygous) cases; such events were not accompanied by point mutations in "hot" codons (12th or 61st) in the remaining allele. Prevalence of A3 and A4 alleles of HRAS-1 oncogene (68 cases) as compared to healthy donors was noted. RB-1 (41 cases) and p53 (62 cases) suppressor genes did not show any alterations in Southern-blot analysis. LOH of chromosome 17p (YNZ-22 probe) was found in 15 of 26 heterozygous CC; 17q (THH-59 probe)--in 4 of 16. Analysis of 175th codon of p53 gene revealed only one case of mutation in 35 CC studied. Finally, we were able to detect genetic alterations in 23 of 40 (58%) CC, that were studied on each parameter using Southern-blot. We failed to find any correlation between various molecular abnormalities or clinical characteristics. The data obtained are in disagreement with the view concerning frequent involvement of p53 antioncogene in chromosome 17p deletions.

  2. Marek's disease virus-encoded analog of microRNA-155 activates the oncogene c-Myc by targeting LTBP1 and suppressing the TGF-β signaling pathway.

    Science.gov (United States)

    Chi, Jia-Qi; Teng, Man; Yu, Zu-Hua; Xu, Hui; Su, Jing-Wei; Zhao, Pu; Xing, Guang-Xu; Liang, Hong-De; Deng, Rui-Guang; Qu, Liang-Hu; Zhang, Gai-Ping; Luo, Jun

    2015-02-01

    Marek's disease virus (MDV) is a representative alpha herpes virus able to induce rapid-onset T-cell lymphoma in its natural host and regarded as an ideal model for the study of virus-induced tumorigenesis. Recent studies have shown that the mdv1-miR-M4-5p, a viral analog of cellular miR-155, is critical for MDV׳s oncogenicity. However, the precise mechanism whereby it was involved in MD lymphomagenesis remained unknown. We have presently identified the host mRNA targets of mdv1-miR-M4-5 and identified the latent TGF-β binding protein 1 (LTBP1) as a critical target for it. We found that during MDV infection, down-regulation of LTBP1 expression by mdv1-miR-M4-5p led to a significant decrease of the secretion and activation of TGF-β1, with suppression of TGF-β signaling and a significant activation of expression of c-Myc, a well-known oncogene which is critical for virus-induced tumorigenesis. Our findings reveal a novel and important mechanism of how mdv1-miR-M4-5p potentially contributes to MDV-induced tumorigenesis. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  3. Rab23 is overexpressed in human bladder cancer and promotes cancer cell proliferation and invasion.

    Science.gov (United States)

    Jiang, Yuanjun; Han, Yushuang; Sun, Chaonan; Han, Chuyang; Han, Ning; Zhi, Weiwei; Qiao, Qiao

    2016-06-01

    Rab23 overexpression has been implicated in several human cancers. However, its expression pattern and biological roles in human bladder cancer have not been elucidated. In this study, we examined Rab23 expression in 93 bladder cancer specimens and analyzed its correlation with clinicopathological parameters. We found that Rab23 was overexpressed in 45 of 93 (48.3 %) cancer specimens. Significant association was found between Rab23 overexpression and tumor invasion depth (p = 0.0027). Rab23 overexpression also negatively correlated with FGFR3 protein expression (p = 0.021). We found that Rab23 expression was lower in normal bladder transitional cell line SV-HUC-1 than in bladder cancer cell lines BIU-87, 5637, and T24. We knocked down Rab23 expression in T24 cancer cells and transfected a Rab23 plasmid in the BIU-87 cell line. Rab23 depletion inhibited cell growth rate and invasion, while its overexpression resulted in increased cell growth and invasion. In addition, we demonstrated that Rab23 depletion decreased and its transfection upregulated expression of cyclin E, c-myc, and MMP-9. Furthermore, we showed that Rab23 knockdown inhibited NF-κB signaling and its overexpression upregulated NF-κB signaling. BAY 11-7082 (NF-κB inhibitor) partly inhibited the effect of Rab23 on cyclin E and MMP-9 expression. In conclusion, the present study demonstrated that Rab23 overexpression facilitates malignant cell growth and invasion in bladder cancer through the NF-κB pathway.

  4. NG2 and phosphacan are present in the astroglial scar after human traumatic spinal cord injury

    Directory of Open Access Journals (Sweden)

    Schoenen Jean

    2009-07-01

    Full Text Available Abstract Background A major class of axon growth-repulsive molecules associated with CNS scar tissue is the family of chondroitin sulphate proteoglycans (CSPGs. Experimental spinal cord injury (SCI has demonstrated rapid re-expression of CSPGs at and around the lesion site. The pharmacological digestion of CSPGs in such lesion models results in substantially enhanced axonal regeneration and a significant functional recovery. The potential therapeutic relevance of interfering with CSPG expression or function following experimental injuries seems clear, however, the spatio-temporal pattern of expression of individual members of the CSPG family following human spinal cord injury is only poorly defined. In the present correlative investigation, the expression pattern of CSPG family members NG2, neurocan, versican and phosphacan was studied in the human spinal cord. Methods An immunohistochemical investigation in post mortem samples of control and lesioned human spinal cords was performed. All patients with traumatic SCI had been clinically diagnosed as having "complete" injuries and presented lesions of the maceration type. Results In sections from control spinal cord, NG2 immunoreactivity was restricted to stellate-shaped cells corresponding to oligodendrocyte precursor cells. The distribution patterns of phosphacan, neurocan and versican in control human spinal cord parenchyma were similar, with a fine reticular pattern being observed in white matter (but also located in gray matter for phosphacan. Neurocan staining was also associated with blood vessel walls. Furthermore, phosphacan, neurocan and versican were present in the myelin sheaths of ventral and dorsal nerve roots axons. After human SCI, NG2 and phosphacan were both detected in the evolving astroglial scar. Neurocan and versican were detected exclusively in the lesion epicentre, being associated with infiltrating Schwann cells in the myelin sheaths of invading peripheral nerve fibres

  5. Hepatocellular alterations and dysregulation of oncogenic pathways in the liver of transgenic mice overexpressing growth hormone

    Science.gov (United States)

    Miquet, Johanna G.; Freund, Thomas; Martinez, Carolina S.; González, Lorena; Díaz, María E.; Micucci, Giannina P.; Zotta, Elsa; Boparai, Ravneet K.; Bartke, Andrzej; Turyn, Daniel; Sotelo, Ana I.

    2013-01-01

    Growth hormone (GH) overexpression throughout life in transgenic mice is associated with the development of liver tumors at old ages. The preneoplastic pathology observed in the liver of young adult GH-overexpressing mice is similar to that present in humans at high risk of hepatic cancer. To elucidate the molecular pathogenesis underlying the pro-oncogenic liver pathology induced by prolonged exposure to elevated GH levels, the activation and expression of several components of signal transduction pathways that have been implicated in hepatocellular carcinogenesis were evaluated in the liver of young adult GH-transgenic mice. In addition, males and females were analyzed in parallel in order to evaluate sexual dimorphism. Transgenic mice from both sexes exhibited hepatocyte hypertrophy with enlarged nuclear size and exacerbated hepatocellular proliferation, which were higher in males. Dysregulation of several oncogenic pathways was observed in the liver of GH-overexpressing transgenic mice. Many signaling mediators and effectors were upregulated in transgenic mice compared with normal controls, including Akt2, NFκB, GSK3β, β-catenin, cyclin D1, cyclin E, c-myc, c-jun and c-fos. The molecular alterations described did not exhibit sexual dimorphism in transgenic mice except for higher gene expression and nuclear localization of cyclin D1 in males. We conclude that prolonged exposure to GH induces in the liver alterations in signaling pathways involved in cell growth, proliferation and survival that resemble those found in many human tumors. PMID:23428905

  6. Hepatocellular alterations and dysregulation of oncogenic pathways in the liver of transgenic mice overexpressing growth hormone.

    Science.gov (United States)

    Miquet, Johanna G; Freund, Thomas; Martinez, Carolina S; González, Lorena; Díaz, María E; Micucci, Giannina P; Zotta, Elsa; Boparai, Ravneet K; Bartke, Andrzej; Turyn, Daniel; Sotelo, Ana I

    2013-04-01

    Growth hormone (GH) overexpression throughout life in transgenic mice is associated with the development of liver tumors at old ages. The preneoplastic pathology observed in the liver of young adult GH-overexpressing mice is similar to that present in humans at high risk of hepatic cancer. To elucidate the molecular pathogenesis underlying the pro-oncogenic liver pathology induced by prolonged exposure to elevated GH levels, the activation and expression of several components of signal transduction pathways that have been implicated in hepatocellular carcinogenesis were evaluated in the liver of young adult GH-transgenic mice. In addition, males and females were analyzed in parallel in order to evaluate sexual dimorphism. Transgenic mice from both sexes exhibited hepatocyte hypertrophy with enlarged nuclear size and exacerbated hepatocellular proliferation, which were higher in males. Dysregulation of several oncogenic pathways was observed in the liver of GH-overexpressing transgenic mice. Many signaling mediators and effectors were upregulated in transgenic mice compared with normal controls, including Akt2, NFκB, GSK3β, β-catenin, cyclin D1, cyclin E, c-myc, c-jun and c-fos. The molecular alterations described did not exhibit sexual dimorphism in transgenic mice except for higher gene expression and nuclear localization of cyclin D1 in males. We conclude that prolonged exposure to GH induces in the liver alterations in signaling pathways involved in cell growth, proliferation and survival that resemble those found in many human tumors.

  7. Multiple factors from bradykinin-challenged astrocytes contribute to the neuronal apoptosis: involvement of astroglial ROS, MMP-9, and HO-1/CO system.

    Science.gov (United States)

    Yang, Chuen-Mao; Hsieh, Hsi-Lung; Lin, Chih-Chung; Shih, Ruey-Horng; Chi, Pei-Ling; Cheng, Shin-Ei; Hsiao, Li-Der

    2013-06-01

    Bradykinin (BK) has been shown to induce the expression of several inflammatory mediators, including reactive oxygen species (ROS) and matrix metalloproteinases (MMPs), in brain astrocytes. These mediators may contribute to neuronal dysfunction and death in various neurological disorders. However, the effects of multiple inflammatory mediators released from BK-challenged astrocytes on neuronal cells remain unclear. Here, we found that multiple factors were released from brain astrocytes (RBA-1) exposed to BK in the conditioned culture media (BK-CM), including ROS, MMP-9, and heme oxygenase-1 (HO-1)/carbon monoxide (CO), leading to neuronal cell (SK-N-SH) death. Exposure of SK-N-SH cells to BK-CM or H2O2 reduced cell viability and induced cell apoptosis which were attenuated by N-acetyl cysteine, indicating a role of ROS in these responses. The effect of BK-CM on cell viability and cell apoptosis was also reversed by immunoprecipitation of BK-CM with anti-MMP-9 antibody (MMP-9-IP-CM) or MMP2/9 inhibitor, suggesting the involvement of MMP-9 in BK-CM-mediated responses. Astroglial HO-1/CO in BK-CM induced cell apoptosis and reduced cell viability which was reversed by hemoglobin. Consistently, the involvement of CO in these cellular responses was revealed by incubation with a CO donor CO-RM2 which was reversed by hemoglobin. The role of HO-1 in BK-CM-induced responses was confirmed by overexpression of HO-1 in SK-N-SH infected with Adv-HO-1. BK-CM-induced cell apoptosis was due to the activation of caspase-3 and cleavage of PARP. Together, we demonstrate that BK-induced several neurotoxic factors, including ROS, MMP-9, and CO released from astrocytes, may induce neuronal death through a caspase-3-dependent apoptotic pathway.

  8. AICAR induces astroglial differentiation of neural stem cells via activating the JAK/STAT3 pathway independently of AMP-activated protein kinase.

    Science.gov (United States)

    Zang, Yi; Yu, Li-Fang; Pang, Tao; Fang, Lei-Ping; Feng, Xu; Wen, Tie-Qiao; Nan, Fa-Jun; Feng, Lin-Yin; Li, Jia

    2008-03-07

    Neural stem cell differentiation and the determination of lineage decision between neuronal and glial fates have important implications in the study of developmental, pathological, and regenerative processes. Although small molecule chemicals with the ability to control neural stem cell fate are considered extremely useful tools in this field, few were reported. AICAR is an adenosine analog and extensively used to activate AMP-activated protein kinase (AMPK), a metabolic "fuel gauge" of the biological system. In the present study, we found an unrecognized astrogliogenic activity of AICAR on not only immortalized neural stem cell line C17.2 (C17.2-NSC), but also primary neural stem cells (NSCs) derived from post-natal (P0) rat hippocampus (P0-NSC) and embryonic day 14 (E14) rat embryonic cortex (E14-NSC). However, another AMPK activator, Metformin, did not alter either the C17.2-NSC or E14-NSC undifferentiated state although both Metformin and AICAR can activate the AMPK pathway in NSC. Furthermore, overexpression of dominant-negative mutants of AMPK in C17.2-NSC was unable to block the gliogenic effects of AICAR. We also found AICAR could activate the Janus kinase (JAK) STAT3 pathway in both C17.2-NSC and E14-NSC but Metformin fails. JAK inhibitor I abolished the gliogenic effects of AICAR. Taken together, these results suggest that the astroglial differentiation effect of AICAR on neural stem cells was acting independently of AMPK and that the JAK-STAT3 pathway is essential for the gliogenic effect of AICAR.

  9. Astroglial redistribution of aquaporin 4 during spongy degeneration in a Canavan disease mouse model.

    Science.gov (United States)

    Clarner, Tim; Wieczorek, Nicola; Krauspe, Barbara; Jansen, Katharina; Beyer, Cordian; Kipp, Markus

    2014-05-01

    Canavan disease is a spongiform leukodystrophy caused by an autosomal recessive mutation in the aspartoacylase gene. Deficiency of oligodendroglial aspartoacylase activity and a subsequent increase of its substrate N-acetylaspartate are the etiologic factors for the disease. N-acetylaspartate acts as a molecular water pump. Therefore, an osmotic-hydrostatic mechanism is thought to be involved in the development of the Canavan disease phenotype. Astrocytes express water transporters and are critically involved in regulating and maintaining water homeostasis in the brain. We used the ASPA(Nur7/Nur7) mouse model of Canavan disease to investigate whether a disturbance of water homeostasis might be involved in the disease's progression. Animals showed an age-dependent impairment of motor performance and spongy degeneration in various brain regions, among the basal ganglia, brain stem, and cerebellar white matter. Astrocyte activation was prominent in regions which displayed less tissue damage, such as the corpus callosum, cortex, mesencephalon, and stratum Purkinje of cerebellar lobe IV. Immunohistochemistry revealed alterations in the cellular distribution of the water channel aquaporin 4 in astrocytes of ASPA(Nur7/Nur7) mice. In control animals, aquaporin 4 was located exclusively in the astrocytic end feet. In contrast, in ASPA(Nur7/Nur7) mice, aquaporin 4 was located throughout the cytoplasm. These results indicate that astroglial regulation of water homeostasis might be involved in the partial prevention of spongy degeneration. These observations highlight aquaporin 4 as a potential therapeutic target for Canavan disease.

  10. Dopamine elevates and lowers astroglial Ca2+ through distinct pathways depending on local synaptic circuitry.

    Science.gov (United States)

    Jennings, Alistair; Tyurikova, Olga; Bard, Lucie; Zheng, Kaiyu; Semyanov, Alexey; Henneberger, Christian; Rusakov, Dmitri A

    2017-03-01

    Whilst astrocytes in culture invariably respond to dopamine with cytosolic Ca2+ rises, the dopamine sensitivity of astroglia in situ and its physiological roles remain unknown. To minimize effects of experimental manipulations on astroglial physiology, here we monitored Ca2+ in cells connected via gap junctions to astrocytes loaded whole-cell with cytosolic indicators in area CA1 of acute hippocampal slices. Aiming at high sensitivity of [Ca2+ ] measurements, we also employed life-time imaging of the Ca2+ indicator Oregon Green BAPTA-1. We found that dopamine triggered a dose-dependent, bidirectional Ca2+ response in stratum radiatum astroglia, a jagged elevation accompanied and followed by below-baseline decreases. The elevation depended on D1/D2 receptors and engaged intracellular Ca2+ storage and removal whereas the dopamine-induced [Ca2+ ] decrease involved D2 receptors only and was sensitive to Ca2+ channel blockade. In contrast, the stratum lacunosum moleculare astroglia generated higher-threshold dopamine-induced Ca2+ responses which did not depend on dopamine receptors and were uncoupled from the prominent inhibitory action of dopamine on local perforant path synapses. Our findings thus suggest that a single neurotransmitter-dopamine-could either elevate or decrease astrocyte [Ca2+ ] depending on the receptors involved, that such actions are specific to the regional neural circuitry and that they may be causally uncoupled from dopamine actions on local synapses. The results also indicate that [Ca2+ ] elevations commonly detected in astroglia can represent the variety of distinct mechanisms acting on the microscopic scale. GLIA 2017;65:447-459. © 2016 The Authors Glia Published by Wiley Periodicals, Inc.

  11. Astroglial Excitability and Gliotransmission: An Appraisal of Ca2+ as a Signalling Route

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    Robert Zorec

    2012-02-01

    Full Text Available Astroglial cells, due to their passive electrical properties, were long considered subservient to neurons and to merely provide the framework and metabolic support of the brain. Although astrocytes do play such structural and housekeeping roles in the brain, these glial cells also contribute to the brain's computational power and behavioural output. These more active functions are endowed by the Ca2+-based excitability displayed by astrocytes. An increase in cytosolic Ca2+ levels in astrocytes can lead to the release of signalling molecules, a process termed gliotransmission, via the process of regulated exocytosis. Dynamic components of astrocytic exocytosis include the vesicular-plasma membrane secretory machinery, as well as the vesicular traffic, which is governed not only by general cytoskeletal elements but also by astrocyte-specific IFs (intermediate filaments. Gliotransmitters released into the ECS (extracellular space can exert their actions on neighbouring neurons, to modulate synaptic transmission and plasticity, and to affect behaviour by modulating the sleep homoeostat. Besides these novel physiological roles, astrocytic Ca2+ dynamics, Ca2+-dependent gliotransmission and astrocyte–neuron signalling have been also implicated in brain disorders, such as epilepsy. The aim of this review is to highlight the newer findings concerning Ca2+ signalling in astrocytes and exocytotic gliotransmission. For this we report on Ca2+ sources and sinks that are necessary and sufficient for regulating the exocytotic release of gliotransmitters and discuss secretory machinery, secretory vesicles and vesicle mobility regulation. Finally, we consider the exocytotic gliotransmission in the modulation of synaptic transmission and plasticity, as well as the astrocytic contribution to sleep behaviour and epilepsy.

  12. Astroglial Pentose Phosphate Pathway Rates in Response to High-Glucose Environments

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    Shinichi Takahashi

    2012-02-01

    Full Text Available ROS (reactive oxygen species play an essential role in the pathophysiology of diabetes, stroke and neurodegenerative disorders. Hyperglycaemia associated with diabetes enhances ROS production and causes oxidative stress in vascular endothelial cells, but adverse effects of either acute or chronic high-glucose environments on brain parenchymal cells remain unclear. The PPP (pentose phosphate pathway and GSH participate in a major defence mechanism against ROS in brain, and we explored the role and regulation of the astroglial PPP in response to acute and chronic high-glucose environments. PPP activity was measured in cultured neurons and astroglia by determining the difference in rate of 14CO2 production from [1-14C]glucose and [6-14C]glucose. ROS production, mainly H2O2, and GSH were also assessed. Acutely elevated glucose concentrations in the culture media increased PPP activity and GSH level in astroglia, decreasing ROS production. Chronically elevated glucose environments also induced PPP activation. Immunohistochemical analyses revealed that chronic high-glucose environments induced ER (endoplasmic reticulum stress (presumably through increased hexosamine biosynthetic pathway flux. Nuclear translocation of Nrf2 (nuclear factor-erythroid 2 p45 subunit-related factor 2, which regulates G6PDH (glyceraldehyde-6-phosphate dehydrogenase by enhancing transcription, was also observed in association with BiP (immunoglobulin heavy-chain-binding protein expression. Acute and chronic high-glucose environments activated the PPP in astroglia, preventing ROS elevation. Therefore a rapid decrease in glucose level seems to enhance ROS toxicity, perhaps contributing to neural damage when insulin levels given to diabetic patients are not properly calibrated and plasma glucose levels are not adequately maintained. These findings may also explain the lack of evidence for clinical benefits from strict glycaemic control during the acute phase of stroke.

  13. Predictive value of BRCA1, ERCC1, ATP7B, PKM2, TOPOI, TOPΟ-IIA, TOPOIIB and C-MYC genes in patients with small cell lung cancer (SCLC who received first line therapy with cisplatin and etoposide.

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    Niki Karachaliou

    Full Text Available BACKGROUND: The aim of the study was to evaluate the predictive value of genes involved in the action of cisplatin-etoposide in Small Cell Lung Cancer (SCLC. METHODS: 184 SCLC patients' primary tumour samples were analyzed for ERCCI, BRCA1, ATP7B, PKM2 TOPOI, TOPOIIA, TOPOIIB and C-MYC mRNA expression. All patients were treated with cisplatin-etoposide. RESULTS: The patients' median age was 63 years and 120 (65% had extended stage, 75 (41% had increased LDH serum levels and 131 (71% an ECOG performance status was 0-1. Patients with limited stage, whose tumours expressed high ERCC1 (p=0.028, PKM2 (p=0.046, TOPOI (p=0.008, TOPOIIA (p=0.002 and TOPOIIB (p<0.001 mRNA had a shorter Progression Free Survival (PFS. In limited stage patients, high expression of ERCC1 (p=0.014, PKM2 (p=0.026, TOPOIIA (p=0.021 and TOPOIIB (p=0.019 was correlated with decreased median overall survival (mOS while in patients with extended stage, only high TOPOIIB expression had a negative impact on Os (p=0.035. The favorable expression signature expression signature (low expression of ERCC1, PKM2, TOPOIIA and TOPOIIB was correlated with significantly better PFS and Os in both LS-SCLC (p<0.001 and p=0.007, respectively and ES-SCLC (p=0.007 and (p=0.011, respectively group. The unfavorable expression signature was an independent predictor for poor PFS (HR: 3.18; p=0.002 and HR: 3.14; p=0.021 and Os (HR: 4.35; p=0.001and HR: 3.32; p=0.019 in both limited and extended stage, respectively. CONCLUSIONS: Single gene's expression analysis as well as the integrated analysis of ERCC1, PKM2, TOPOIIA and TOPOIIB may predict treatment outcome in patients with SCLC. These findings should be further validated in a prospective study.

  14. Aquaporin-4 in Astroglial Cells in the CNS and Supporting Cells of Sensory Organs—A Comparative Perspective

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    Corinna Gleiser

    2016-08-01

    Full Text Available The main water channel of the brain, aquaporin-4 (AQP4, is one of the classical water-specific aquaporins. It is expressed in many epithelial tissues in the basolateral membrane domain. It is present in the membranes of supporting cells in most sensory organs in a specifically adapted pattern: in the supporting cells of the olfactory mucosa, AQP4 occurs along the basolateral aspects, in mammalian retinal Müller cells it is highly polarized. In the cochlear epithelium of the inner ear, it is expressed basolaterally in some cells but strictly basally in others. Within the central nervous system, aquaporin-4 (AQP4 is expressed by cells of the astroglial family, more specifically, by astrocytes and ependymal cells. In the mammalian brain, AQP4 is located in high density in the membranes of astrocytic endfeet facing the pial surface and surrounding blood vessels. At these locations, AQP4 plays a role in the maintenance of ionic homeostasis and volume regulation. This highly polarized expression has not been observed in the brain of fish where astroglial cells have long processes and occur mostly as radial glial cells. In the brain of the zebrafish, AQP4 immunoreactivity is found along the radial extent of astroglial cells. This suggests that the polarized expression of AQP4 was not present at all stages of evolution. Thus, a polarized expression of AQP4 as part of a control mechanism for a stable ionic environment and water balanced occurred at several locations in supporting and glial cells during evolution. This initially basolateral membrane localization of AQP4 is shifted to highly polarized expression in astrocytic endfeet in the mammalian brain and serves as a part of the neurovascular unit to efficiently maintain homeostasis.

  15. Brain Barriers and a Subpopulation of Astroglial Progenitors of Developing Human Forebrain Are Immunostained for the Glycoprotein YKL-40

    DEFF Research Database (Denmark)

    Bjørnbak, Camilla; Brøchner, Christian B; Larsen, Lars A

    2014-01-01

    and subventricular zones showed specific YKL-40 reactivity confined to pericytes. Furthermore, a population of YKL-40-positive, small, rounded cells was identified in the ventricular and subventricular zones. Real-time quantitative RT-PCR analysis showed strong YKL-40 mRNA expression in the leptomeninges...... in controlling local angiogenesis and access of peripheral cells to the forebrain via secretion from leptomeningeal cells, choroid plexus epithelium and pericytes. Furthermore, we suggest that the small, rounded, YKL-40-positive cells represent a subpopulation of astroglial progenitors, and that YKL-40 could...

  16. Antioxidant Properties of Berberis aetnensis C. Presl (Berberidaceae Roots Extract and Protective Effects on Astroglial Cell Cultures

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    Agata Campisi

    2014-01-01

    Full Text Available Berberis aetnensis C. Presl (Berberidaceae is a bushy-spiny shrub common on Mount Etna (Sicily. We demonstrated that the alkaloid extract of roots of B. aetnensis C. Presl contains prevalently berberine and berbamine, possesses antimicrobial properties, and was able to counteract the upregulation evoked by glutamate of tissue transglutaminase in primary rat astroglial cell cultures. Until now, there are no reports regarding antioxidant properties of B. aetnensis C. Presl collected in Sicily. Air-dried, powdered roots of B. aetnensis C. Presl were extracted, identified, and quantified by HPLC. We assessed in cellular free system its effect on superoxide anion, radicals scavenging activity of antioxidants against free radicals like the 1,1-diphenyl-2-picrylhydrazyl radical, and the inhibition of xanthine oxidase activity. In primary rat astroglial cell cultures, exposed to glutamate, we evaluated the effect of the extract on glutathione levels and on intracellular production of reactive oxygen species generated by glutamate. The alkaloid extract of B. aetnensis C. Presl inhibited superoxide anion, restored to control values, the decrease of GSH levels, and the production of reactive oxygen species. Potent antioxidant activities of the alkaloid extract of roots of B. aetnensis C. Presl may be one of the mechanisms by which the extract is effective against health disorders associated to oxidative stress.

  17. Activation of astroglial calcium signaling by endogenous metabolites succinate and gamma-hydroxybutyrate in the nucleus accumbens

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    Tünde eMolnár

    2011-12-01

    Full Text Available Accumulating evidence suggests that different energy metabolites play a role not only in neuronal but also in glial signalling. Recently, astroglial Ca2+ transients evoked by the major citric acid cycle metabolite succinate (SUC and gamma-hydroxybutyrate (GHB that enters the citric acid cycle via SUC have been described in the brain reward area, the nucleus accumbens (NAc. Cells responding to SUC by Ca2+ transient constitute a subset of ATP-responsive astrocytes that are activated in a neuron-independent way. In this study we show that GHB-evoked Ca2+ transients were also found to constitute a subset of ATP-responsive astrocytes in the NAc. Repetitive Ca2+ dynamics evoked by GHB suggested that Ca2+ was released from internal stores. Similarly to SUC, the GHB-response was also characterized by an effective concentration of 50 µM. We observed that the number of ATP-responsive cells decreased with increasing concentration of either SUC or GHB. Moreover, the concentration dependence of the number of ATP-responsive cells were highly identical as a function of both [SUC] and [GHB], suggesting a mutual receptor for SUC and GHB, therefore implying the existence of a distinct GHB-recognizing astroglial SUC receptor in the brain. The SUC-evoked Ca2+ signal remained in mice lacking GABAB receptor type 1 subunit in the presence and absence of the N-Methyl-D-Aspartate (NMDA receptor antagonist (2R-amino-5-phosphonovaleric acid (APV, indicating action mechanisms independent of the GABAB or NMDA receptor subtypes. By molecular docking calculations we found that residues R99, H103, R252 and R281 of the binding crevice of the kidney SUC-responsive membrane receptor SUCNR1 (GPCR91 also predict interaction with GHB, further implying similar GHB and SUC action mechanisms. We conclude that the astroglial action of SUC and GHB may represent a link between brain energy states and Ca2+ signalling in astrocytic networks.

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

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    Maria Pia Abruzzese

    2016-12-01

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

  19. Mitogenic signaling pathways in the liver of growth hormone (GH)-overexpressing mice during the growth period.

    Science.gov (United States)

    Martinez, Carolina S; Piazza, Verónica G; González, Lorena; Fang, Yimin; Bartke, Andrzej; Turynl, Danie; Miquet, Johanna G; Sotelo, Ana I

    2016-01-01

    Growth hormone (GH) is a pleiotropic hormone that triggers STATs, ERK1/2 and Akt signaling, related to cell growth and proliferation. Transgenic mice overexpressing GH present increased body size, with a disproportionate liver enlargement due to hypertrophy and hyperplasia of the hepatocytes. We had described enhanced mitogenic signaling in liver of young adult transgenic mice. We now evaluate the activation of these signaling cascades during the growth period and relate them to the morphological alterations found. Signaling mediators, cell cycle regulators and transcription factors involved in cellular growth in the liver of GH-overexpressing growing mice were assessed by immunoblotting, RT-qPCR and immunohistochemistry. Hepatocyte enlargement can be seen as early as 2-weeks of age in GH-overexpressing animals, although it is more pronounced in young adults. Levels of cell cycle mediators PCNA and cyclin D1, and transcription factor c-Jun increase with age in transgenic mice with no changes in normal mice, whereas c-Myc levels are higher in 2-week-old transgenic animals and cyclin E levels decline with age for both genotypes. STAT3, Akt and GSK3 present higher activation in the adult transgenic mice than in the growing animals, while for c-Src and mTOR, phosphorylation in GH-overexpressing mice is higher than in control siblings at 4 and 9 weeks of age. No significant changes are observed for ERK1/2, neither by age or genotype. Thus, the majority of the mitogenic signaling pathways are gradually up-regulated in the liver of GH-transgenic mice, giving rise to the hepatic morphological changes these mice exhibit.

  20. Effect of Nrf2 activators on release of glutathione, cysteinylglycine and homocysteine by human U373 astroglial cells

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    Megan L. Steele

    2013-01-01

    This study compares four known Nrf2 activators, R-α-Lipoic acid (LA, tert-butylhydroquinone (TBHQ, sulforaphane (SFN and Polygonum cuspidatum extract containing 50% resveratrol (PC-Res for their effects on astroglial release of GSH and CysGly. GSH levels increased dose-dependently in response to all four drugs. Sulforaphane produced the most potent effect, increasing GSH by up to 2.4-fold. PC-Res increased GSH up to 1.6-fold, followed by TBHQ (1.5-fold and LA (1.4-fold. GSH is processed by the ectoenzyme, γ-glutamyl transpeptidase, to form CysGly. Once again, SFN produced the most potent effect, increasing CysGly by up to 1.7-fold, compared to control cells. TBHQ and PC-Res both induced fold increases of 1.3, followed by LA with a fold increase of 1.2. The results from the present study showed that sulforaphane, followed by lipoic acid, resveratrol and Polygonum multiflorum were all identified as potent “GSH and Cys-Gly boosters”.

  1. Neutrophils Induce Astroglial Differentiation and Migration of Human Neural Stem Cells via C1q and C3a Synthesis

    Science.gov (United States)

    Benavente, Francisca; Flanagan, Lisa; Uchida, Nobuko; Anderson, Aileen J.

    2017-01-01

    Inflammatory processes play a key role in pathophysiology of many neurologic diseases/trauma, but the effect of immune cells and factors on neurotransplantation strategies remains unclear. We hypothesized that cellular and humoral components of innate immunity alter fate and migration of human neural stem cells (hNSC). In these experiments, conditioned media collected from polymorphonuclear leukocytes (PMN) selectively increased hNSC astrogliogenesis and promoted cell migration in vitro. PMN were shown to generate C1q and C3a; exposure of hNSC to PMN-synthesized concentrations of these complement proteins promoted astrogliogenesis and cell migration. Furthermore, in vitro, Abs directed against C1q and C3a reversed the fate and migration effects observed. In a proof-of-concept in vivo experiment, blockade of C1q and C3a transiently altered hNSC migration and reversed astroglial fate after spinal cord injury. Collectively, these data suggest that modulation of the innate/humoral inflammatory microenvironment may impact the potential of cell-based therapies for recovery and repair following CNS pathology. PMID:28687659

  2. ATF6alpha promotes astroglial activation and neuronal survival in a chronic mouse model of Parkinson's disease.

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    Koji Hashida

    Full Text Available Accumulating evidence suggests a crucial role for the unfolded protein response (UPR in Parkinson's disease (PD. In this study, we investigated the relevance of the UPR in a mouse model of chronic MPTP/probenecid (MPTP/P injection, which causes severe and persistent degeneration of dopaminergic neurons. Enhanced activation of the UPR branches, including ATF6α and PERK/eIF2α/ATF4, was observed after MPTP/P injections into mice. Deletion of the ATF6α gene accelerated neuronal degeneration and ubiquitin accumulation relatively early in the MPTP/P injection course. Surprisingly, astroglial activation was strongly suppressed, and production of the brain-derived neurotrophic factor (BDNF and anti-oxidative genes, such as heme oxygenase-1 (HO-1 and xCT, in astrocytes were reduced in ATF6α -/- mice after MPTP/P injections. Decreased BDNF expression in ATF6α -/- mice was associated with decreased expression of GRP78, an ATF6α-dependent molecular chaperone in the ER. Decreased HO-1 and xCT levels were associated with decreased expression of the ATF4-dependent pro-apoptotic gene CHOP. Consistent with these results, administration of the UPR-activating reagent tangeretin (5,6,7,8,4'-pentamethoxyflavone; IN19 into mice enhanced the expression of UPR-target genes in both dopaminergic neurons and astrocytes, and promoted neuronal survival after MPTP/P injections. These results suggest that the UPR is activated in a mouse model of chronic MPTP/P injection, and contributes to the survival of nigrostriatal dopaminergic neurons, in part, through activated astrocytes.

  3. The Sarcoglycan complex is expressed in the cerebrovascular system and is specifically regulated by astroglial Cx30 channels

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    Anne-Cécile eBoulay

    2015-02-01

    Full Text Available Astrocytes, the most prominent glial cell type in the brain, send specialized processes called endfeet, around blood vessels and express a large molecular repertoire regulating the cerebrovascular system physiology. One of the most striking properties of astrocyte endfeet is their enrichment in gap junction protein Connexin 43 and 30 (Cx43 and Cx30 allowing in particular for direct intercellular trafficking of ions and small signaling molecules through perivascular astroglial networks. In this study, we addressed the specific role of Cx30 at the gliovascular interface. Using an inactivation mouse model for Cx30 (Cx30Δ/Δ, we showed that absence of Cx30 does not affect blood-brain barrier (BBB organization and permeability. However, it results in the cerebrovascular fraction, in a strong upregulation of Sgcg encoding γ-Sarcoglycan (SG, a member of the Dystrophin-associated protein complex (DAPC connecting cytoskeleton and the extracellular matrix. The same molecular event occurs in Cx30T5M/T5M mutated mice, where Cx30 channels are closed, demonstrating that Sgcg regulation relied on Cx30 channel functions. We further characterized the expression of other Sarcoglycan complex (SGC molecules in the cerebrovascular system and showed the presence of α-, β-, δ-, γ-, ε- and ζ- SG, as well as Sarcospan. Their expression was however not modified in Cx30Δ/Δ. These results suggest that a full SGC might be present in the cerebrovascular system, and that expression of one of its member, γ-Sarcoglycan, depends on Cx30 channels. As described in skeletal muscles, the SGC may contribute to membrane stabilization and signal transduction in the cerebrovascular system, which may therefore be regulated by Cx30 channel-mediated functions.

  4. The stimulatory effect of the octadecaneuropeptide ODN on astroglial antioxidant enzyme systems is mediated through a GPCR

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    Yosra eHamdi

    2012-11-01

    Full Text Available Astroglial cells possess an array of cellular defense systems, including superoxide dismutase (SOD and catalase antioxidant enzymes, to prevent damage caused by oxidative stress on the central nervous system. Astrocytes specifically synthesize and release endozepines, a family of regulatory peptides including the octadecaneuropeptide (ODN. ODN is the ligand of both central-type benzodiazepine receptors (CBR, and an adenylyl cyclase- and phospholipase C-coupled receptor. We have recently shown that ODN is a potent protective agent that prevents hydrogen peroxide (H2O2-induced inhibition of SOD and catalase activities and stimulation of cell apoptosis in astrocytes. The purpose of the present study was to investigate the type of receptor involved in ODN-induced inhibition of SOD and catalase in cultured rat astrocytes. We found that ODN induced a rapid stimulation of SOD and catalase gene transcription in a concentration-dependent manner. In addition, 0.1 nM ODN blocked H2O2-evoked reduction of both mRNA levels and activities of SOD and catalase. Furthermore, the inhibitory actions of ODN on the deleterious effects of H2O2 on SOD and catalase were abrogated by the metabotropic ODN receptor antagonist cyclo1–8[Dleu5]OP, but not by the CBR antagonist flumazenil. Finally, the protective action of ODN against H2O2-evoked inhibition of endogenous antioxidant systems in astrocytes was protein kinase A (PKA-dependent, but protein kinase C-independent. Taken together, these data demonstrate for the first time that ODN, acting through its metabotropic receptor coupled to the PKA pathway, prevents oxidative stress-induced alteration of antioxidant enzyme expression and activities. The peptide ODN is thus a potential candidate for the development of specific agonists that would selectively mimic its protective activity.

  5. Caveolin-1 expression is variably displayed in astroglial-derived tumors and absent in oligodendrogliomas: concrete premises for a new reliable diagnostic marker in gliomas.

    Science.gov (United States)

    Cassoni, Paola; Senetta, Rebecca; Castellano, Isabella; Ortolan, Erika; Bosco, Martino; Magnani, Ivana; Ducati, Alessandro

    2007-05-01

    Caveolins are basic constituents of flask-shaped cell membrane microdomains (caveolae), which are involved in many cell functions, including signalling, trafficking, and cellular growth control. The distribution of caveolae within the normal brain and in brain tumors is controversial. In the present study, we describe the expression of caveolin-1 (cav-1) in 64 brain tumors of different grade, of either astroglial or oligodendroglial origin. All studied astrocitomas of any grade (from II to IV) were cav-1 positive, displaying staining patterns and intensity specifically associated to the different tumor grades. In all glioblastomas and gliosarcomas, cav-1 staining was extremely intense, typically localized at the cell membrane and recognized a variable percentage of cells, including the majority of spindle cells and palisade-oriented perinecrotic cells. In anaplastic astrocytomas, a less intense membrane staining or a cytoplasmic dotlike immunoreactivity were present, the latter being almost the exclusive pattern observed in diffuse astrocitomas grade II. In contrast to astroglial tumors, the striking totality of grade II oligodendrogliomas and the large majority of grade III were lacking cav-1 expression. Interestingly, a cav-1 distribution overlapping the pattern described in tissues was observed also in primary cell cultures of human glioblastomas and astrocytomas, and also in one established glioblastoma cell line (U251 MG), analyzed by means of confocal microscopy and flow cytometry. In conclusion, among astroglial tumors cav-1 expression varies in distribution, pattern, and intensity specifically according to tumor types and grades. The association between tumor progression and a more structured membranous pattern of cav-1 expression could suggest the hypothesis of a neoplastic shift towards a mesenchymal phenotype, whose behavioral and biologic significance worth further studies. Finally, the lack of cav-1 immunoreactivity in oligodendrogliomas suggests its

  6. Stimulation of nuclear receptor REV-ERBs regulates tumor necrosis factor-induced expression of proinflammatory molecules in C6 astroglial cells

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    Morioka, Norimitsu, E-mail: mnori@hiroshima-u.ac.jp; Tomori, Mizuki; Zhang, Fang Fang; Saeki, Munenori; Hisaoka-Nakashima, Kazue; Nakata, Yoshihiro

    2016-01-08

    Under physiological conditions, astrocytes maintain homeostasis in the CNS. Following inflammation and injury to the CNS, however, activated astrocytes produce neurotoxic molecules such as cytokines and chemokines, amplifying the initial molecular-cellular events evoked by inflammation and injury. Nuclear receptors REV-ERBα and REV-ERBβ (REV-ERBs) are crucial in the regulation of inflammation- and metabolism-related gene transcription. The current study sought to elucidate a role of REV-ERBs in rat C6 astroglial cells on the expression of inflammatory molecules following stimulation with the neuroinflammatory cytokine tumor necrosis factor (TNF). Stimulation of C6 cells with TNF (10 ng/ml) significantly increased the mRNA expression of CCL2, interleukin-6 (IL-6), inducible nitric oxide synthase (iNOS), and matrix metalloprotease (MMP)-9, but not fibroblast growth factor-2 (FGF-2), cyclooxygenase-2 (COX-2) and MMP-2. Treatment with either REV-ERB agonists GSK4112 or SR9009 significantly blocked TNF-induced upregulation of CCL2 mRNA and MMP-9 mRNA, but not IL-6 mRNA and iNOS mRNA expression. Furthermore, treatment with RGFP966, a selective histone deacetylase 3 (HDAC3) inhibitor, potently reversed the inhibitory effects of GSK4112 on TNF-induced expression of MMP-9 mRNA, but not CCL2 mRNA. Expression of Rev-erbs mRNA in C6 astroglial cells, primary cultured rat cortical and spinal astrocytes was confirmed by reverse transcription polymerase chain reaction. Together, the findings demonstrate an anti-inflammatory effect, downregulating of MMP-9 and CCL2 transcription, of astroglial REV-ERBs activation through HDAC3-dependent and HDAC3-independent mechanisms. - Highlights: • Rev-erbα mRNA and Rev-erbβ mRNA are expressed in C6 astroglial cells. • TNF increases the expression of CCL2, IL-6, MMP-9 and iNOS mRNA. • REV-ERB activation inhibits CCL2 mRNA and MMP-9 mRNA expression. • HDAC3 activity is involved in the inhibitory effect of REV-ERB on MMP-9 induction.

  7. Oral administration of a Gemini vitamin D analog, a synthetic triterpenoid and the combination prevents mammary tumorigenesis driven by ErbB2 overexpression

    Science.gov (United States)

    So, Jae Young; Wahler, Joseph E.; Yoon, Taesook; Smolarek, Amanda K.; Lin, Yong; Shih, Weichung Joe; Maehr, Hubert; Uskokovic, Milan; Liby, Karen T.; Sporn, Michael B.; Suh, Nanjoo

    2013-01-01

    Human epidermal growth factor receptor 2 (HER2 or ErbB2), a member of ErbB receptor tyrosine kinases, is overexpressed in approximately 20 % of human breast cancer, and the ErbB2 signaling pathway is a critical therapeutic target for ErbB2-overexpressing breast cancer. We investigated the inhibitory effects of the Gemini vitamin D analog BXL0124, the synthetic triterpenoid CDDO-Im and the combination on the tumorigenesis of ErbB2-overexpressing breast cancer. MMTV-ErbB2/neu transgenic mice were treated with BXL0124, CDDO-Im or the combination from 3 months of age until the end of the experiment. Formation and growth of MMTV-ErbB2/neu mammary tumors were monitored every week, and all three treatments delayed the development of mammary tumors without significant toxicity. Decreased activation of ErbB2 as well as other ErbB receptors, ErbB1 and ErbB3, in MMTV-ErbB2/neu mammary tumors was shown by all treatments. Protein levels of downstream targets of the ErbB2 signaling pathway, including activated-Erk1/2, activated-Akt, c-Myc, CycD1 and Bcl2, were repressed by all three treatments, with the combination treatment exhibiting the strongest effects. To investigate therapeutic efficacy, the combination of BXL0124 and CDDO-Im was given to MMTV-ErbB2/neu mice after mammary tumors were established between 23-30 weeks of age. Short-term treatment with the combination did not show effects on tumor growth nor the ErbB2 signaling pathway. The present study demonstrates BXL0124, CDDO-Im and the combination as potential agents for prevention, but not treatment, against the tumorigenesis of ErbB2-overexpressing breast cancer. PMID:23856074

  8. Oral administration of a gemini vitamin D analog, a synthetic triterpenoid and the combination prevents mammary tumorigenesis driven by ErbB2 overexpression.

    Science.gov (United States)

    So, Jae Young; Wahler, Joseph E; Yoon, Taesook; Smolarek, Amanda K; Lin, Yong; Shih, Weichung Joe; Maehr, Hubert; Uskokovic, Milan; Liby, Karen T; Sporn, Michael B; Suh, Nanjoo

    2013-09-01

    HER2 (or ErbB2), a member of ErbB receptor tyrosine kinases, is overexpressed in approximately 20% of human breast cancer, and the ErbB2 signaling pathway is a critical therapeutic target for ErbB2-overexpressing breast cancer. We investigated the inhibitory effects of the Gemini vitamin D analog BXL0124, the synthetic triterpenoid CDDO-Im and the combination on the tumorigenesis of ErbB2-overexpressing breast cancer. MMTV-ErbB2/neu transgenic mice were treated with BXL0124, CDDO-Im, or the combination from three months of age until the end of the experiment. Formation and growth of MMTV-ErbB2/neu mammary tumors were monitored every week, and all three treatments delayed the development of mammary tumors without significant toxicity. Decreased activation of ErbB2 as well as other ErbB receptors, ErbB1 and ErbB3, in MMTV-ErbB2/neu mammary tumors was shown by all treatments. Protein levels of downstream targets of the ErbB2 signaling pathway, including activated-Erk1/2, activated-Akt, c-Myc, CycD1, and Bcl2, were repressed by all three treatments, with the combination treatment exhibiting the strongest effects. To investigate therapeutic efficacy, the combination of BXL0124 and CDDO-Im was given to MMTV-ErbB2/neu mice after mammary tumors were established between 23 and 30 weeks of age. Short-term treatment with the combination did not show effects on tumor growth nor the ErbB2 signaling pathway. The present study shows BXL0124, CDDO-Im, and the combination as potential agents for prevention, but not treatment, against the tumorigenesis of ErbB2-overexpressing breast cancer.

  9. The PVT-1 oncogene is a Myc protein target that is overexpressed in transformed cells.

    Science.gov (United States)

    Carramusa, Letizia; Contino, Flavia; Ferro, Arianna; Minafra, Luigi; Perconti, Giovanni; Giallongo, Agata; Feo, Salvatore

    2007-11-01

    The human PVT-1 gene is located on chromosome 8 telomeric to the c-Myc gene and it is frequently involved in the translocations occurring in variant Burkitt's lymphomas and murine plasmacytomas. It has been proposed that PVT-1 regulates c-Myc gene transcription over a long distance. To get new insights into the functional relationships between the two genes, we have investigated PVT-1 and c-Myc expression in normal human tissues and in transformed cells. Our findings indicate that PVT-1 expression is restricted to a relative low number of normal tissues compared to the wide distribution of c-Myc mRNA, whereas the gene is highly expressed in many transformed cell types including neuroblastoma cells that do not express c-Myc. Reporter gene assays were used to dissect the PVT-1 promoter and to identify the region responsible for the elevated expression observed in transformed cells. This region contains two putative binding sites for Myc proteins. The results of transfection experiments in RAT1-MycER cells and chromatin immunoprecipitation (ChIP) assays in proliferating and differentiated neuroblastoma cells indicate that PVT-1 is a downstream target of Myc proteins.

  10. Noninvasive 89Zr-Transferrin PET Shows Improved Tumor Targeting Compared with 18F-FDG PET in MYC-Overexpressing Human Triple-Negative Breast Cancer.

    Science.gov (United States)

    Henry, Kelly E; Dilling, Thomas R; Abdel-Atti, Dalya; Edwards, Kimberly J; Evans, Michael J; Lewis, Jason S

    2018-01-01

    The current standard for breast PET imaging is 18F-FDG. The heterogeneity of 18F-FDG uptake in breast cancer limits its utility, varying greatly among receptor status, histopathologic subtypes, and proliferation markers. 18F-FDG PET often exhibits nonspecific internalization and low specificity and sensitivity, especially with tumors smaller than 1 cm3 MYC is a protein involved in oncogenesis and is overexpressed in triple-negative breast cancer (TNBC). Increased surface expression of transferrin receptor (TfR) is a downstream event of MYC upregulation and has been validated as a clinically relevant target for molecular imaging. Transferrin labeled with 89Zr has successfully identified MYC status in many cancer subtypes preclinically and been shown to predict response and changes in oncogene status via treatment with small-molecule inhibitors that target MYC and PI3K signaling pathways. We hypothesized that 89Zr-transferrin PET will noninvasively detect MYC and TfR and improve upon the current standard of 18F-FDG PET for MYC-overexpressing TNBC. Methods: In this study, 89Zr-transferrin and 18F-FDG imaging were compared in preclinical models of TNBC. TNBC cells (MDA-MB-157, MDA-MB-231, and Hs578T) were treated with bromodomain-containing protein 4 (BRD4) inhibitors JQ1 and OTX015 (0.5-1 μM). Cell proliferation, gene expression, and protein expression were assayed to explore the effects of these inhibitors on MYC and TfR. Results: Head-to-head comparison showed that 89Zr-transferrin targets TNBC tumors significantly better (P PET imaging and biodistribution studies in MDA-MB-231 and MDA-MB-157 xenografts and a patient-derived xenograft model of TNBC. c-Myc and TfR gene expression was decreased upon treatment with BRD4 inhibitors and c-MYC small interfering RNA (P PET imaging and biodistribution studies. 89Zr-transferrin is a useful tool to interrogate MYC via TfR-targeted PET imaging in TNBC. © 2018 by the Society of Nuclear Medicine and Molecular Imaging.

  11. Nestin-positive mesenchymal stem cells favour the astroglial lineage in neural progenitors and stem cells by releasing active BMP4

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    Leprince Pierre

    2004-09-01

    Full Text Available Abstract Background Spontaneous repair is limited after CNS injury or degeneration because neurogenesis and axonal regrowth rarely occur in the adult brain. As a result, cell transplantation has raised much interest as potential treatment for patients with CNS lesions. Several types of cells have been considered as candidates for such cell transplantation and replacement therapies. Foetal brain tissue has already been shown to have significant effects in patients with Parkinson's disease. Clinical use of the foetal brain tissue is, however, limited by ethical and technical problems as it requires high numbers of grafted foetal cells and immunosuppression. Alternatively, several reports suggested that mesenchymal stem cells, isolated from adult bone marrow, are multipotent cells and could be used in autograft approach for replacement therapies. Results In this study, we addressed the question of the possible influence of mesenchymal stem cells on neural stem cell fate. We have previously reported that adult rat mesenchymal stem cells are able to express nestin in defined culture conditions (in the absence of serum and after 25 cell population doublings and we report here that nestin-positive (but not nestin-negative mesenchymal stem cells are able to favour the astroglial lineage in neural progenitors and stem cells cultivated from embryonic striatum. The increase of the number of GFAP-positive cells is associated with a significant decrease of the number of Tuj1- and O4-positive cells. Using quantitative RT-PCR, we demonstrate that mesenchymal stem cells express LIF, CNTF, BMP2 and BMP4 mRNAs, four cytokines known to play a role in astroglial fate decision. In this model, BMP4 is responsible for the astroglial stimulation and oligodendroglial inhibition, as 1 this cytokine is present in a biologically-active form only in nestin-positive mesenchymal stem cells conditioned medium and 2 anti-BMP4 antibodies inhibit the nestin-positive mesenchymal

  12. Amplification and Overexpression of the L-MYC Proto-Oncogene in Ovarian Carcinomas

    Science.gov (United States)

    Wu, Rong; Lin, Lin; Beer, David G.; Ellenson, Lora H.; Lamb, Barbara J.; Rouillard, Jean-Marie; Kuick, Rork; Hanash, Samir; Schwartz, Donald R.; Fearon, Eric R.; Cho, Kathleen R.

    2003-01-01

    Gene amplification is an important mechanism of oncogene activation in various human cancers, including ovarian carcinomas (OvCas). We used restriction landmark genomic scanning (RLGS) to detect amplified DNA fragments in the genomes of 47 primary OvCas. Visual analysis of the RLGS gel images revealed several OvCa samples with spots of greater intensity than corresponding spots from normal tissues, indicating possible DNA amplification in specific tumors. Two primary tumors (E1 and S12) shared four high-intensity spots. A recently developed informatics tool termed Virtual Genome Scans was used to compare the RLGS patterns in these tumors with patterns predicted from the human genome sequence. Virtual Genome Scans determined that three of the four fragments localized to chromosome 1p34-35, a region containing the proto-oncogene L-MYC. Sixty-eight primary OvCas, including 40 analyzed by RLGS, were screened by quantitative polymerase chain reaction (PCR) for possible amplification of L-MYC. Ten tumors with increased L-MYC copy number were identified, including tumor E1, which showed an ∼24-fold increase in copy number compared to normal DNA. Southern analysis of several tumors confirmed the quantitative PCR results. Using sequence tagged site (STS) markers flanking L-MYC, increased DNA copy number in tumor E1 was found to span the region flanking L-MYC between D1S432 and D1S463 (≈3.1 Mb). Other tumors showed amplification only at the L-MYC locus. Using oligonucleotide microarrays, L-MYC was found to be more frequently overexpressed in OvCas than either c-MYC or N-MYC relative to ovarian surface epithelium. Quantitative reverse transcriptase-PCR analysis confirmed elevated L-MYC expression in a substantial fraction of OvCas, including nine of nine tumors with increased L-MYC copy number. The data implicate L-MYC gene amplification and/or overexpression in human OvCa pathogenesis. PMID:12707044

  13. Wnt signaling and c-Myc in intestinal epithelium

    NARCIS (Netherlands)

    Muncan, V.

    2007-01-01

    constantly produce cells from a stem cell reservoir that give rise to proliferating transit amplifying cells, which subsequently differentiate and are positioned in their proper compartments. This process has to be under stringent control to ensure life-long tissue homeostasis. It has now become

  14. Metformin targets c-MYC oncogene to prevent prostate cancer

    OpenAIRE

    Akinyeke, Tunde; Matsumura, Satoko; Wang, Xinying; Wu, Yingjie; Schalfer, Eric D.; Saxena, Anjana; Yan, Wenbo; Logan, Susan K; Li, Xin

    2013-01-01

    Prostate cancer (PCa) is the second leading cause of cancer-related death in American men and many PCa patients develop skeletal metastasis. Current treatment modalities for metastatic PCa are mostly palliative with poor prognosis. Epidemiological studies indicated that patients receiving the diabetic drug metformin have lower PCa risk and better prognosis, suggesting that metformin may have antineoplastic effects. The mechanism by which metformin acts as chemopreventive agent to impede PCa i...

  15. A Conditioned Medium of Umbilical Cord Mesenchymal Stem Cells Overexpressing Wnt7a Promotes Wound Repair and Regeneration of Hair Follicles in Mice

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    Liang Dong

    2017-01-01

    Full Text Available Mesenchymal stem cells (MSCs can affect the microenvironment of a wound and thereby accelerate wound healing. Wnt proteins act as key mediators of skin development and participate in the formation of skin appendages such as hair. The mechanisms of action of MSCs and Wnt proteins on skin wounds are largely unknown. Here, we prepared a Wnt7a-containing conditioned medium (Wnt-CM from the supernatant of cultured human umbilical cord-MSCs (UC-MSCs overexpressing Wnt7a in order to examine the effects of this CM on cutaneous healing. Our results revealed that Wnt-CM can accelerate wound closure and induce regeneration of hair follicles. Meanwhile, Wnt-CM enhanced expression of extracellular matrix (ECM components and cell migration of fibroblasts but inhibited the migratory ability and expression of K6 and K16 in keratinocytes by enhancing expression of c-Myc. However, we found that the CM of fibroblasts treated with Wnt-CM (HFWnt-CM-CM can also promote wound repair and keratinocyte migration; but there was no increase in the number of hair follicles of regeneration. These data indicate that Wnt7a and UC-MSCs have synergistic effects: they can accelerate wound repair and induce hair regeneration via cellular communication in the wound microenvironment. Thus, this study opens up new avenues of research on the mechanisms underlying wound repair.

  16. Flagella Overexpression Attenuates Salmonella Pathogenesis

    OpenAIRE

    Xinghong Yang; Theresa Thornburg; Zhiyong Suo; SangMu Jun; Amanda Robison; Jinquan Li; Timothy Lim; Ling Cao; Teri Hoyt; Recep Avci; Pascual, David W.

    2012-01-01

    Flagella are cell surface appendages involved in a number of bacterial behaviors, such as motility, biofilm formation, and chemotaxis. Despite these important functions, flagella can pose a liability to a bacterium when serving as potent immunogens resulting in the stimulation of the innate and adaptive immune systems. Previous work showing appendage overexpression, referred to as attenuating gene expression (AGE), was found to enfeeble wild-type Salmonella. Thus, this approach was adapted to...

  17. Flagella overexpression attenuates Salmonella pathogenesis.

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    Xinghong Yang

    Full Text Available Flagella are cell surface appendages involved in a number of bacterial behaviors, such as motility, biofilm formation, and chemotaxis. Despite these important functions, flagella can pose a liability to a bacterium when serving as potent immunogens resulting in the stimulation of the innate and adaptive immune systems. Previous work showing appendage overexpression, referred to as attenuating gene expression (AGE, was found to enfeeble wild-type Salmonella. Thus, this approach was adapted to discern whether flagella overexpression could induce similar attenuation. To test its feasibility, flagellar filament subunit FliC and flagellar regulon master regulator FlhDC were overexpressed in Salmonella enterica serovar Typhimurium wild-type strain H71. The results show that the expression of either FliC or FlhDC alone, and co-expression of the two, significantly attenuates Salmonella. The flagellated bacilli were unable to replicate within macrophages and thus were not lethal to mice. In-depth investigation suggests that flagellum-mediated AGE was due to the disruptive effects of flagella on the bacterial membrane, resulting in heightened susceptibilities to hydrogen peroxide and bile. Furthermore, flagellum-attenuated Salmonella elicited elevated immune responses to Salmonella presumably via FliC's adjuvant effect and conferred robust protection against wild-type Salmonella challenge.

  18. Flagella Overexpression Attenuates Salmonella Pathogenesis

    Science.gov (United States)

    Yang, Xinghong; Thornburg, Theresa; Suo, Zhiyong; Jun, SangMu; Robison, Amanda; Li, Jinquan; Lim, Timothy; Cao, Ling; Hoyt, Teri; Avci, Recep; Pascual, David W.

    2012-01-01

    Flagella are cell surface appendages involved in a number of bacterial behaviors, such as motility, biofilm formation, and chemotaxis. Despite these important functions, flagella can pose a liability to a bacterium when serving as potent immunogens resulting in the stimulation of the innate and adaptive immune systems. Previous work showing appendage overexpression, referred to as attenuating gene expression (AGE), was found to enfeeble wild-type Salmonella. Thus, this approach was adapted to discern whether flagella overexpression could induce similar attenuation. To test its feasibility, flagellar filament subunit FliC and flagellar regulon master regulator FlhDC were overexpressed in Salmonella enterica serovar Typhimurium wild-type strain H71. The results show that the expression of either FliC or FlhDC alone, and co-expression of the two, significantly attenuates Salmonella. The flagellated bacilli were unable to replicate within macrophages and thus were not lethal to mice. In-depth investigation suggests that flagellum-mediated AGE was due to the disruptive effects of flagella on the bacterial membrane, resulting in heightened susceptibilities to hydrogen peroxide and bile. Furthermore, flagellum-attenuated Salmonella elicited elevated immune responses to Salmonella presumably via FliC’s adjuvant effect and conferred robust protection against wild-type Salmonella challenge. PMID:23056473

  19. Consequences of over-expression of rat Scavenger Receptor, SR-BI, in an adrenal cell model

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    Azhar Salman

    2006-12-01

    Full Text Available Abstract Background The plasma membrane scavenger receptor, SR-BI, mediates the 'selective uptake' process by which cholesteryl esters (CE from exogenously supplied HDL are taken up by target cells. Recent work suggests that dimer and higher order oligomeric forms of the SR-BI protein are important to this process. SR-BI has been shown to be particularly associated with microvilli and microvillar channels found at the cell surface of steroidogenic cells, and a study with the hormone stimulated adrenal gland has shown impressive changes in the size and complexity of the microvillar compartment as the mass of CE uptake (and accompanying steroidogenesis fluctuates. In the present study, we examine a cell line in which we overexpress the SR-BI protein to determine if morphological, biochemical and functional events associated with SR-BI in a controlled cell system are similar to those observed in the intact mammalian adrenal which is responsive to systemic factors. Methods Y1-BS1 mouse adrenocortical cells were transiently transfected using rat SR-BI-pcDNA6-V5-His, rat SR-BI-pcDNA6-cMyc-His or control pcDNA6-V5-His vector construct using a CaPO4 precipitation technique. Twenty four hours after transfection, cells were treated with, or without, Bt2cAMP, and SR-BI expression, CE uptake, and steroidogenesis was measured. SR-BI dimerization and cell surface architectural changes were assessed using immunoelectron microscopic techniques. Results Overexpression of the scavenger receptor protein, SR-BI, in Y1-BS1 cells results in major alterations in cell surface architecture designed to increase uptake of HDL supplied-CEs. Changes include 1 the formation of crater-like erosions of the surface with multiple double membraned channel structures lining the craters, and 2 dimerized formations of SR-BI lining the newly formed craters and associated double membraned channels. Conclusion These data show that overexpression of the scavenger receptor protein, SR

  20. NUCKS overexpression in breast cancer

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    Kittas Christos

    2009-08-01

    Full Text Available Abstract Background NUCKS (Nuclear, Casein Kinase and Cyclin-dependent Kinase Substrate is a nuclear, DNA-binding and highly phosphorylated protein. A number of reports show that NUCKS is highly expressed on the level of mRNA in several human cancers, including breast cancer. In this work, NUCKS expression on both RNA and protein levels was studied in breast tissue biopsies consisted of invasive carcinomas, intraductal proliferative lesions, benign epithelial proliferations and fibroadenomas, as well as in primary cultures derived from the above biopsies. Specifically, in order to evaluate the level of NUCKS protein in correlation with the histopathological features of breast disease, immunohistochemistry was employed on paraffin sections of breast biopsies of the above types. In addition, NUCKS expression was studied by means of Reverse Transcription PCR (RT-PCR, real-time PCR (qRT-PCR and Western immunoblot analyses in the primary cell cultures developed from the same biopsies. Results The immunohistochemical Results showed intense NUCKS staining mostly in grade I and II breast carcinomas compared to normal tissues. Furthermore, NUCKS was moderate expressed in benign epithelial proliferations, such as adenosis and sclerosing adenosis, and highly expressed in intraductal lesions, specifically in ductal carcinomas in situ (DCIS. It is worth noting that all the fibroadenoma tissues examined were negative for NUCKS staining. RT-PCR and qRT-PCR showed an increase of NUCKS expression in cells derived from primary cultures of proliferative lesions and cancerous tissues compared to the ones derived from normal breast tissues and fibroadenomas. This increase was also confirmed by Western immunoblot analysis. Although NUCKS is a cell cycle related protein, its expression does not correlate with Ki67 expression, neither in tissue sections nor in primary cell cultures. Conclusion The results show overexpression of the NUCKS protein in a number of non

  1. Tuning Escherichia coli for membrane protein overexpression

    NARCIS (Netherlands)

    Wagner, Samuel; Klepsch, Mirjam M.; Schlegel, Susan; Appel, Ansgar; Draheim, Roger; Tarry, Michael; Hogbom, Martin; van Wijk, Klaas J.; Slotboom, Dirk J.; Persson, Jan O.; de Gier, Jan-Willem; Högbom, Martin

    2008-01-01

    A simple generic method for optimizing membrane protein overexpression in Escherichia coli is still lacking. We have studied the physiological response of the widely used "Walker strains" C41(DE3) and C43(DE3), which are derived from BL21(DE3), to membrane protein overexpression. For unknown

  2. The dual face of connexin-based astroglial Ca(2+) communication: a key player in brain physiology and a prime target in pathology.

    Science.gov (United States)

    De Bock, Marijke; Decrock, Elke; Wang, Nan; Bol, Mélissa; Vinken, Mathieu; Bultynck, Geert; Leybaert, Luc

    2014-10-01

    For decades, studies have been focusing on the neuronal abnormalities that accompany neurodegenerative disorders. Yet, glial cells are emerging as important players in numerous neurological diseases. Astrocytes, the main type of glia in the central nervous system , form extensive networks that physically and functionally connect neuronal synapses with cerebral blood vessels. Normal brain functioning strictly depends on highly specialized cellular cross-talk between these different partners to which Ca(2+), as a signaling ion, largely contributes. Altered intracellular Ca(2+) levels are associated with neurodegenerative disorders and play a crucial role in the glial responses to injury. Intracellular Ca(2+) increases in single astrocytes can be propagated toward neighboring cells as intercellular Ca(2+) waves, thereby recruiting a larger group of cells. Intercellular Ca(2+) wave propagation depends on two, parallel, connexin (Cx) channel-based mechanisms: i) the diffusion of inositol 1,4,5-trisphosphate through gap junction channels that directly connect the cytoplasm of neighboring cells, and ii) the release of paracrine messengers such as glutamate and ATP through hemichannels ('half of a gap junction channel'). This review gives an overview of the current knowledge on Cx-mediated Ca(2+) communication among astrocytes as well as between astrocytes and other brain cell types in physiology and pathology, with a focus on the processes of neurodegeneration and reactive gliosis. Research on Cx-mediated astroglial Ca(2+) communication may ultimately shed light on the development of targeted therapies for neurodegenerative disorders in which astrocytes participate. This article is part of a Special Issue entitled: Calcium signaling in health and disease. Guest Editors: Geert Bultynck, Jacques Haiech, Claus W. Heizmann, Joachim Krebs, and Marc Moreau. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Significance of Aurora B overexpression in hepatocellular carcinoma. Aurora B Overexpression in HCC

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    Lin Zhong-Zhe

    2010-08-01

    Full Text Available Abstract Background To investigate the significance of Aurora B expression in hepatocellular carcinoma (HCC. Methods The Aurora B and Aurora A mRNA level was measured in 160 HCCs and the paired nontumorous liver tissues by reverse transcription-polymerase chain reaction. Mutations of the p53 and β-catenin genes were analyzed in 134 and 150 tumors, respectively, by direct sequencing of exon 2 to exon 11 of p53 and exon 3 of β-catenin. Anticancer effects of AZD1152-HQPA, an Aurora B kinase selective inhibitor, were examined in Huh-7 and Hep3B cell lines. Results Aurora B was overexpressed in 98 (61% of 160 HCCs and in all 7 HCC cell lines examined. The overexpression of Aurora B was associated with Aurora A overexpression (P = 0.0003 and p53 mutation (P = 0.002 and was inversely associated with β-catenin mutation (P = 0.002. Aurora B overexpression correlated with worse clinicopathologic characteristics. Multivariate analysis confirmed that Aurora B overexpression was an independent poor prognostic factor, despite its interaction with Aurora A overexpression and mutations of p53 and β-catenin. In Huh-7 and Hep3B cells, AZD1152-HQPA induced proliferation blockade, histone H3 (Ser10 dephosphorylation, cell cycle disturbance, and apoptosis. Conclusion Aurora B overexpression is an independent molecular marker predicting tumor invasiveness and poor prognosis of HCC. Aurora B kinase selective inhibitors are potential therapeutic agents for HCC treatment.

  4. Quality control of overexpressed membrane proteins

    NARCIS (Netherlands)

    Geertsma, Eric R.; Groeneveld, Maarten; Slotboom, Dirk-Jan; Poolman, Bert

    2008-01-01

    Overexpression of membrane proteins in Escherichia coli frequently leads to the formation of aggregates or inclusion bodies, which is undesirable for most studies. Ideally, one would like to optimize the expression conditions by monitoring simultaneously and rapidly both the amounts of properly

  5. Hand1 overexpression inhibits medulloblastoma metastasis

    Energy Technology Data Exchange (ETDEWEB)

    Asuthkar, Swapna; Guda, Maheedhara R. [Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, IL 61656 (United States); Martin, Sarah E. [Department of Pathology, University of Illinois College of Medicine at Peoria, Peoria, IL 61656 (United States); Antony, Reuben; Fernandez, Karen [Department of Pediatrics, University of Illinois College of Medicine at Peoria, Peoria, IL 61656 (United States); Lin, Julian [Department of Neurosurgery, University of Illinois College of Medicine at Peoria, Peoria, IL 61656 (United States); Tsung, Andrew J. [Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, IL 61656 (United States); Department of Neurosurgery, University of Illinois College of Medicine at Peoria, Peoria, IL 61656 (United States); Illinois Neurological Institute, Peoria, IL 61656 (United States); Velpula, Kiran K., E-mail: velpula@uic.edu [Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, IL 61656 (United States); Department of Neurosurgery, University of Illinois College of Medicine at Peoria, Peoria, IL 61656 (United States)

    2016-08-19

    Medulloblastoma (MB) is the most frequent malignant pediatric brain tumor. Current treatment includes surgery, radiation and chemotherapy. However, ongoing treatment in patients is further classified according to the presence or absence of metastasis. Since metastatic medulloblastoma are refractory to current treatments, there is need to identify novel biomarkers that could be used to reduce metastatic potential, and more importantly be targeted therapeutically. Previously, we showed that ionizing radiation-induced uPAR overexpression is associated with increased accumulation of β-catenin in the nucleus. We further demonstrated that uPAR protein act as cytoplasmic sequestration factor for a novel basic helix-loop-helix transcription factor, Hand1. Among the histological subtypes classical and desmoplastic subtypes account for the majority while large cell/anaplastic variant is most commonly associated with metastatic disease. In this present study using immunohistochemical approach and patient data mining for the first time, we demonstrated that Hand1 expression is observed to be downregulated in all the subtypes of medulloblastoma. Previously we showed that Hand1 overexpression regulated medulloblastoma angiogenesis and here we investigated the role of Hand1 in the context of Epithelial-Mesenchymal Transition (EMT). Moreover, UW228 and D283 cells overexpressing Hand1 demonstrated decreased-expression of mesenchymal markers (N-cadherin, β-catenin and SOX2); metastatic marker (SMA); and increased expression of epithelial marker (E-cadherin). Strikingly, human pluripotent stem cell antibody array showed that Hand1 overexpression resulted in substantial decrease in pluripotency markers (Nanog, Oct3/4, Otx2, Flk1) suggesting that Hand1 expression may be essential to attenuate the EMT and our findings underscore a novel role for Hand1 in medulloblastoma metastasis. - Highlights: • Hand1 expression is downregulated in Medulloblastoma. • Hand1 over expression reduce

  6. Cdc45 Is a Critical Effector of Myc-Dependent DNA Replication Stress

    Directory of Open Access Journals (Sweden)

    Seetha V. Srinivasan

    2013-05-01

    Full Text Available c-Myc oncogenic activity is thought to be mediated in part by its ability to generate DNA replication stress and subsequent genomic instability when deregulated. Previous studies have demonstrated a nontranscriptional role for c-Myc in regulating DNA replication. Here, we analyze the mechanisms by which c-Myc deregulation generates DNA replication stress. We find that overexpression of c-Myc alters the spatiotemporal program of replication initiation by increasing the density of early-replicating origins. We further show that c-Myc deregulation results in elevated replication-fork stalling or collapse and subsequent DNA damage. Notably, these phenotypes are independent of RNA transcription. Finally, we demonstrate that overexpression of Cdc45 recapitulates all c-Myc-induced replication and damage phenotypes and that Cdc45 and GINS function downstream of Myc.

  7. Frequent Nek1 overexpression in human gliomas

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Jun [School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai (China); Neurosurgery Department, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai (China); Cai, Yu, E-mail: aihaozuqiu22@163.com [School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai (China); Neurosurgery Department, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai (China); Liu, Pin [Med-X Research Institute, Shanghai Jiao Tong University, Shanghai (China); Zhao, Weiguo [Neurosurgery Department, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai (China)

    2016-08-05

    Never in mitosis A (NIMA)-related kinase 1 (Nek1) regulates cell cycle progression to mitosis. Its expression and potential functions in human gliomas have not been studied. Here, our immunohistochemistry (IHC) assay and Western blot assay results showed that Nek1 expression was significantly upregulated in fresh and paraffin-embedded human glioma tissues. Its level in normal brain tissues was low. Nek1 overexpression in human gliomas was correlated with the proliferation marker (Ki-67), tumor grade, Karnofsky performance scale (KPS) and more importantly, patients’ poor survival. Further studies showed that Nek1 expression level was also increased in multiple human glioma cell lines (U251-MG, U87-MG, U118, H4 and U373). Significantly, siRNA-mediated knockdown of Nek1 inhibited glioma cell (U87-MG/U251-MG) growth. Nek1 siRNA also sensitized U87-MG/U251-MG cells to temozolomide (TMZ), causing a profound apoptosis induction and growth inhibition. The current study indicates Nek1 might be a novel and valuable oncotarget of glioma, it is important for glioma cell growth and TMZ-resistance. - Highlights: • Nek1 is upregulated in multiple human glioma tissues and cell lines. • Nek1 overexpression correlates with glioma grades and patients’ KPS score. • Nek1 overexpression correlates with patients’ poor overall survival. • siRNA knockdown of Nek1 inhibits glioma cell growth. • siRNA knockdown of Nek1 sensitizes human glioma cells to temozolomide.

  8. 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.

  9. Overexpressed TP73 induces apoptosis in medulloblastoma

    Directory of Open Access Journals (Sweden)

    Perlaky Laszlo

    2007-07-01

    Full Text Available Abstract Background Medulloblastoma is the most common malignant brain tumor of childhood. Children who relapse usually die of their disease, which reflects resistance to radiation and/or chemotherapy. Improvements in outcome require a better understanding of the molecular basis of medulloblastoma growth and treatment response. TP73 is a member of the TP53 tumor suppressor gene family that has been found to be overexpressed in a variety of tumors and mediates apoptotic responses to genotoxic stress. In this study, we assessed expression of TP73 RNA species in patient tumor specimens and in medulloblastoma cell lines, and manipulated expression of full-length TAp73 and amino-terminal truncated ΔNp73 to assess their effects on growth. Methods We analyzed medulloblastoma samples from thirty-four pediatric patients and the established medulloblastoma cell lines, Daoy and D283MED, for expression of TP73 RNA including the full-length transcript and the 5'-terminal variants that encode the ΔNp73 isoform, as well as TP53 RNA using quantitative real time-RTPCR. Protein expression of TAp73 and ΔNp73 was quantitated with immunoblotting methods. Clinical outcome was analyzed based on TP73 RNA and p53 protein expression. To determine effects of overexpression or knock-down of TAp73 and ΔNp73 on cell cycle and apoptosis, we analyzed transiently transfected medulloblastoma cell lines with flow cytometric and TUNEL methods. Results Patient medulloblastoma samples and cell lines expressed full-length and 5'-terminal variant TP73 RNA species in 100-fold excess compared to non-neoplastic brain controls. Western immunoblot analysis confirmed their elevated levels of TAp73 and amino-terminal truncated ΔNp73 proteins. Kaplan-Meier analysis revealed trends toward favorable overall and progression-free survival of patients whose tumors display TAp73 RNA overexpression. Overexpression of TAp73 or ΔNp73 induced apoptosis under basal growth conditions in vitro and

  10. Nucleophosmin is overexpressed in thyroid tumors

    Energy Technology Data Exchange (ETDEWEB)

    Pianta, Annalisa; Puppin, Cinzia [Dipartimento di Scienze e Tecnologie Biomediche, Universita di Udine, Udine (Italy); Franzoni, Alessandra; Fabbro, Dora [Azienda Ospedaliero-Universitaria ' S. Maria della Misericordia' Udine, Udine (Italy); Di Loreto, Carla [Dipartimento di Ricerche Mediche e Morfologiche, Universita di Udine, Udine (Italy); Bulotta, Stefania [Department of Pharmacobiological Sciences, Universita di Catanzaro ' Magna Graecia' , Catanzaro (Italy); Deganuto, Marta; Paron, Igor; Tell, Gianluca [Dipartimento di Scienze e Tecnologie Biomediche, Universita di Udine, Udine (Italy); Puxeddu, Efisio [Department of Internal Medicine, Universita di Perugia, Perugia (Italy); Filetti, Sebastiano [Department of Clinical Sciences, Universita di Roma ' La Sapienza' , Roma (Italy); Russo, Diego [Department of Pharmacobiological Sciences, Universita di Catanzaro ' Magna Graecia' , Catanzaro (Italy); Damante, Giuseppe, E-mail: giuseppe.damante@uniud.it [Dipartimento di Scienze e Tecnologie Biomediche, Universita di Udine, Udine (Italy); Azienda Ospedaliero-Universitaria ' S. Maria della Misericordia' Udine, Udine (Italy)

    2010-07-02

    Nucleophosmin (NPM) is a protein that contributes to several cell functions. Depending on the context, it can act as an oncogene or tumor suppressor. No data are available on NPM expression in thyroid cells. In this work, we analyzed both NPM mRNA and protein levels in a series of human thyroid tumor tissues and cell lines. By using immunohistochemistry, NPM overexpression was detected in papillary, follicular, undifferentiated thyroid cancer, and also in follicular benign adenomas, indicating it as an early event during thyroid tumorigenesis. In contrast, various levels of NPM mRNA levels as detected by quantitative RT-PCR were observed in tumor tissues, suggesting a dissociation between protein and transcript expression. The same behavior was observed in the normal thyroid FRTL5 cell lines. In these cells, a positive correlation between NPM protein levels, but not mRNA, and proliferation state was detected. By using thyroid tumor cell lines, we demonstrated that such a post-mRNA regulation may depend on NPM binding to p-Akt, whose levels were found to be increased in the tumor cells, in parallel with reduction of PTEN. In conclusion, our present data demonstrate for the first time that nucleophosmin is overexpressed in thyroid tumors, as an early event of thyroid tumorigenesis. It seems as a result of a dysregulation occurring at protein and not transcriptional level related to an increase of p-Akt levels of transformed thyrocytes.

  11. Overexpression of Id1 in transgenic mice promotes mammary basal stem cell activity and breast tumorigenesis

    Science.gov (United States)

    Won, Hee-Young; Jang, Ki-Seok; Min, Kyueng-Whan; Jang, Si-Hyong; Woo, Jong-Kyu; Oh, Seung Hyun; Kong, Gu

    2015-01-01

    Inhibitor of differentiation/DNA binding (Id)1 is a crucial regulator of mammary development and breast cancer progression. However, its effect on stemness and tumorigenesis in mammary epithelial cells remains undefined. Herein, we demonstrate that Id1 induces mammary tumorigenesis by increasing normal and malignant mammary stem cell (MaSC) activities in transgenic mice. MaSC-enriched basal cell expansion and increased self-renewal and in vivo regenerative capacity of MaSCs are observed in the mammary glands of MMTV-Id1 transgenic mice. Furthermore, MMTV-Id1 mice develop ductal hyperplasia and mammary tumors with highly expressed basal markers. Id1 also increases breast cancer stem cell (CSC) population and activity in human breast cancer lines. Moreover, the effects of Id1 on normal and malignant stem cell activities are mediated by the Wnt/c-Myc pathway. Collectively, these findings provide in vivo genetic evidence of Id1 functions as an oncogene in breast cancer and indicate that Id1 regulates mammary basal stem cells by activating the Wnt/c-Myc pathway, thereby contributing to breast tumor development. PMID:25938540

  12. Targeted anticancer therapy: overexpressed receptors and nanotechnology.

    Science.gov (United States)

    Akhtar, Mohd Javed; Ahamed, Maqusood; Alhadlaq, Hisham A; Alrokayan, Salman A; Kumar, Sudhir

    2014-09-25

    Targeted delivery of anticancer drugs to cancer cells and tissues is a promising field due to its potential to spare unaffected cells and tissues, but it has been a major challenge to achieve success in these therapeutic approaches. Several innovative approaches to targeted drug delivery have been devised based on available knowledge in cancer biology and on technological advancements. To achieve the desired selectivity of drug delivery, nanotechnology has enabled researchers to design nanoparticles (NPs) to incorporate anticancer drugs and act as nanocarriers. Recently, many receptor molecules known to be overexpressed in cancer have been explored as docking sites for the targeting of anticancer drugs. In principle, anticancer drugs can be concentrated specifically in cancer cells and tissues by conjugating drug-containing nanocarriers with ligands against these receptors. Several mechanisms can be employed to induce triggered drug release in response to either endogenous trigger or exogenous trigger so that the anticancer drug is only released upon reaching and preferentially accumulating in the tumor tissue. This review focuses on overexpressed receptors exploited in targeting drugs to cancerous tissues and the tumor microenvironment. We briefly evaluate the structure and function of these receptor molecules, emphasizing the elegant mechanisms by which certain characteristics of cancer can be exploited in cancer treatment. After this discussion of receptors, we review their respective ligands and then the anticancer drugs delivered by nanotechnology in preclinical models of cancer. Ligand-functionalized nanocarriers have delivered significantly higher amounts of anticancer drugs in many in vitro and in vivo models of cancer compared to cancer models lacking such receptors or drug carrying nanocarriers devoid of ligand. This increased concentration of anticancer drug in the tumor site enabled by nanotechnology could have a major impact on the efficiency of cancer

  13. Overexpression of osteoprotegerin promotes preosteoblast differentiation to mature osteoblasts

    NARCIS (Netherlands)

    Yu, Hongyou; de Vos, Paul; Ren, Yijin

    OBJECTIVE: The hypothesis of the present study is that overexpression of osteoprotegerin (OPG) promotes preosteoblast maturation. MATERIALS AND METHODS: The preosteoblast cell line MC3T3-E1 was transfected with OPG overexpression. OPG expression was confirmed by enzyme-linked immunosorbent assay

  14. Vldlr overexpression causes hyperactivity in rats

    Directory of Open Access Journals (Sweden)

    Iwata Keiko

    2012-10-01

    Full Text Available Abstract Background Reelin regulates neuronal positioning in cortical brain structures and neuronal migration via binding to the lipoprotein receptors Vldlr and Lrp8. Reeler mutant mice display severe brain morphological defects and behavioral abnormalities. Several reports have implicated reelin signaling in the etiology of neurodevelopmental and psychiatric disorders, including autism, schizophrenia, bipolar disorder, and depression. Moreover, it has been reported that VLDLR mRNA levels are increased in the post-mortem brain of autistic patients. Methods We generated transgenic (Tg rats overexpressing Vldlr, and examined their histological and behavioral features. Results Spontaneous locomotor activity was significantly increased in Tg rats, without detectable changes in brain histology. Additionally, Tg rats tended to show performance deficits in the radial maze task, suggesting that their spatial working memory was slightly impaired. Thus, Vldlr levels may be involved in determining locomotor activity and memory function. Conclusions Unlike reeler mice, patients with neurodevelopmental or psychiatric disorders do not show striking neuroanatomical aberrations. Therefore, it is notable, from a clinical point of view, that we observed behavioral phenotypes in Vldlr-Tg rats in the absence of neuroanatomical abnormalities.

  15. DEK oncogene is overexpressed during melanoma progression.

    Science.gov (United States)

    Riveiro-Falkenbach, Erica; Ruano, Yolanda; García-Martín, Rosa M; Lora, David; Cifdaloz, Metehan; Acquadro, Francesco; Ballestín, Claudio; Ortiz-Romero, Pablo L; Soengas, María S; Rodríguez-Peralto, José L

    2017-03-01

    DEK is an oncoprotein involved in a variety of cellular functions, such as DNA repair, replication, and transcriptional control. DEK is preferentially expressed in actively proliferating and malignant cells, including melanoma cell lines in which DEK was previously demonstrated to play a critical role in proliferation and chemoresistance. Still, the impact of this protein in melanoma progression remains unclear. Thus, we performed a comprehensive analysis of DEK expression in different melanocytic tumors. The immunostaining results of 303 tumors demonstrated negligible DEK expression in benign lesions. Conversely, malignant lesions, particularly in metastatic cases, were largely positive for DEK expression, which was partially associated with genomic amplification. Importantly, DEK overexpression was correlated with histological features of aggressiveness in primary tumors and poor prognosis in melanoma patients. In conclusion, our study provides new insight into the involvement of DEK in melanoma progression, as well as proof of concept for its potential application as a marker and therapeutic target of melanoma. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  16. Dimethylarginine Dimethylaminohydrolase Overexpression enhances Insulin Sensitivity

    Science.gov (United States)

    Sydow, Karsten; Mondon, Carl E.; Schrader, Joerg; Konishi, Hakuoh; Cooke, John P.

    2011-01-01

    Objective Previous studies suggest that nitric oxide (NO) may modulate insulin-induced uptake of glucose in insulin-sensitive tissues. Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of NO synthase (NOS). We hypothesized that a reduction in endogenous ADMA would increase NO synthesis and thereby enhance insulin sensitivity. Methods and Results To test this hypothesis we employed a transgenic mouse in which we overexpressed human dimethylarginine dimethylaminohydrolase (DDAH-I). The DDAH-I mice had lower plasma ADMA at all ages (22–70 weeks) by comparison to wild-type (WT) littermates. With a glucose challenge, WT mice showed a prompt increase in ADMA, whereas DDAH-I mice had a blunted response. Furthermore, DDAH-I mice had a blunted increase in plasma insulin and glucose levels after glucose challenge, with a 50% reduction in the insulin resistence index, consistent with enhanced sensitivity to insulin. In liver, we observed an increased Akt phosphorylation in the DDAH-I mice after i.p. glucose challenge. Incubation of skeletal muscle from WT mice ex vivo with ADMA (2μM) markedly suppressed insulin-induced glycogen synthesis in fast-twitch but not slow-twitch muscle. Conclusions These findings suggest that the endogenous NOS inhibitor ADMA reduces insulin sensitivity, consistent with previous observations that NO plays a role in insulin sensitivity. PMID:18239148

  17. E1a promotes c-Myc-dependent replicative stress: Implications in glioblastoma radiosensitization

    OpenAIRE

    Valero, María Llanos; Cimas, Francisco Jose; Arias, Laura; Melgar-Rojas, Pedro; García, Elena; Callejas-Valera, Juan Luis; García-Cano, Jesús; Serrano-Oviedo, Leticia; Ángel de la Cruz-Morcillo, Miguel; Sánchez-Pérez, Isabel; Sánchez-Prieto, Ricardo

    2013-01-01

    The E1a gene from adenovirus is known to be a potent inducer of chemo/radiosensitivity in a wide range of tumors. However, the molecular bases of its radiosensitizer properties are still poorly understood. In an attempt to study this effect, U87MG cells, derived from a radio-resistant tumor as glioblastoma, where infected with lentivirus carrying E1a gene developing an acute sensitivity to ionizing radiation. The induction of radiosensitivity correlated with a marked G2/M phase accumulation a...

  18. Treatment of Multiple Myeloma with VLA4-targeted Nanoparticles Delivering Novel c-MYC Inhibitor Prodrug

    Science.gov (United States)

    2012-09-01

    Bagnasco, L., Malacarne, D., Melchiori, A., Valente, P., Millo, E., Bruno, S., Basso, S., and Parodi, S. A retro-inverso peptide homologous to...81. 25. Ruoslahti, E. RGD and other recognition sequences for integrins. Annu Rev Cell Dev Bioi. 1996; 12697-715. 26. Ria, R., Vacca, A., Ribatti...Haematologica. 2002; 87(8):836-845. 27. Temming, K., Schiffelers, R.M., Molema, G., and Kok, R.J. RGD -based strategies for selective delivery of

  19. Treatment of Endocrine-Resistant Breast Cancer with a Small Molecule c-Myc Inhibitor

    Science.gov (United States)

    2016-08-01

    myeloid leukemia [21-23]. Based on our results, we tested whether JQ1 can suppress ERα expression. As shown in Figure 2G, treatment of MCF7 cells with...al. Small-molecule inhibition of BRD4 as a new potent approach to eliminate leukemic stem- and progenitor cells in acute myeloid leukemia AML...tamoxifen, bromodomain, resistance 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 19a. NAME OF RESPONSIBLE PERSON

  20. Cdk2 suppresses cellular senescence induced by the c-myc oncogene.

    Science.gov (United States)

    Campaner, Stefano; Doni, Mirko; Hydbring, Per; Verrecchia, Alessandro; Bianchi, Lucia; Sardella, Domenico; Schleker, Thomas; Perna, Daniele; Tronnersjö, Susanna; Murga, Matilde; Fernandez-Capetillo, Oscar; Barbacid, Mariano; Larsson, Lars-Gunnar; Amati, Bruno

    2010-01-01

    Activated oncogenes induce compensatory tumour-suppressive responses, such as cellular senescence or apoptosis, but the signals determining the main outcome remain to be fully understood. Here, we uncover a role for Cdk2 (cyclin-dependent kinase 2) in suppressing Myc-induced senescence. Short-term activation of Myc promoted cell-cycle progression in either wild-type or Cdk2 knockout mouse embryo fibroblasts (MEFs). In the knockout MEFs, however, the initial hyper-proliferative response was followed by cellular senescence. Loss of Cdk2 also caused sensitization to Myc-induced senescence in pancreatic beta-cells or splenic B-cells in vivo, correlating with delayed lymphoma onset in the latter. Cdk2-/- MEFs also senesced upon ectopic Wnt signalling or, without an oncogene, upon oxygen-induced culture shock. Myc also causes senescence in cells lacking the DNA repair protein Wrn. However, unlike loss of Wrn, loss of Cdk2 did not enhance Myc-induced replication stress, implying that these proteins suppress senescence through different routes. In MEFs, Myc-induced senescence was genetically dependent on the ARF-p53-p21Cip1 and p16INK4a-pRb pathways, p21Cip1 and p16INK4a being selectively induced in Cdk2-/- cells. Thus, although redundant for cell-cycle progression and development, Cdk2 has a unique role in suppressing oncogene- and/or stress-induced senescence. Pharmacological inhibition of Cdk2 induced Myc-dependent senescence in various cell types, including a p53-null human cancer cell line. Our data warrant re-assessment of Cdk2 as a therapeutic target in Myc- or Wnt-driven tumours.

  1. C-MYC Involvement in Chronic Lymphocytic Leukemia (CLL): A Molecular and Cytogenetic Update.

    Science.gov (United States)

    Fonseka, Lakshan N; Tirado, Carlos A

    2015-01-01

    Chronic lymphocytic leukemia (CLL) is a disorder entailing the slow proliferation of B-cell lymphocytes in the bone marrow and blood. In 2015, it is estimated that 14,620 patients will be diagnosed with CLL, and approximately 4,650 patients will die due to disease progression. CLL typically presents in patients about 71 years of age. Initially, the patients exhibit leukocytosis; however, as the disease progresses, they experience splenomegaly, lymphadenopathy, hepatomegaly, anemia, and infections. Although about 84% of CLL patients will survive for five years or more, CLL cases that report MYC (8q24) translocations with IGH, IGK, IGL, and TCR genes have poor prognoses and low survival rates. Recent studies have shown data supporting both a positive correlation and no correlation between disease progression and MYC expression. Nonetheless, other studies have revealed new information on multiple MYC-dependent pathways responsible for leukemogenesis and tumorigenesis. Herein, we summarize the current molecular nd cytogenetic findings in MYC-associated CLL, with focus on the underlying MYC-dependent mechanisms of leukemogenesis and MYC-associated CLL progression and treatment regimen.

  2. Neuroglobin Overexpression Inhibits AMPK Signaling and Promotes Cell Anabolism.

    Science.gov (United States)

    Cai, Bin; Li, Wenjun; Mao, XiaoOu; Winters, Ali; Ryou, Myoung-Gwi; Liu, Ran; Greenberg, David A; Wang, Ning; Jin, Kunlin; Yang, Shao-Hua

    2016-03-01

    Neuroglobin (Ngb) is a recently discovered globin with preferential localization to neurons. Growing evidence indicates that Ngb has distinct physiological functions separate from the oxygen storage and transport roles of other globins, such as hemoglobin and myoglobin. We found increased ATP production and decreased glycolysis in Ngb-overexpressing immortalized murine hippocampal cell line (HT-22), in parallel with inhibition of AMP-activated protein kinase (AMPK) signaling and activation of acetyl-CoA carboxylase (ACC). In addition, lipid and glycogen content was increased in Ngb-overexpressing HT-22 cells. AMPK signaling was also inhibited in the brain and heart from Ngb-overexpressing transgenic mice. Although Ngb overexpression did not change glycogen content in whole brain, glycogen synthase was activated in cortical neurons of Ngb-overexpressing mouse brain and Ngb overexpression primary neurons. Moreover, lipid and glycogen content was increased in hearts derived from Ngb-overexpressing mice. These findings suggest that Ngb functions as a metabolic regulator and enhances cellular anabolism through the inhibition of AMPK signaling.

  3. Phenotypic effects of membrane protein overexpression in Saccharomyces cerevisiae

    Science.gov (United States)

    Melén, Karin; Blomberg, Anders; von Heijne, Gunnar

    2006-07-01

    Large-scale protein overexpression phenotype screens provide an important complement to the more common gene knockout screens. Here, we have targeted the so far poorly understood Saccharomyces cerevisiae membrane proteome and report growth phenotypes for a strain collection overexpressing 600 C-terminally tagged integral membrane proteins grown both under normal and three different stress conditions. Although overexpression of most membrane proteins reduce the growth rate in synthetic defined medium, we identify a large number of proteins that, when overexpressed, confer specific resistance to various stress conditions. Our data suggest that regulation of glycosylphosphatidylinositol anchor biosynthesis and the Na+/K+ homeostasis system constitute major downstream targets of the yeast PKA/RAS pathway and point to a possible connection between the early secretory pathway and the cells' response to oxidative stress. We also have quantified the expression levels for >550 membrane proteins, facilitating the choice of well expressing proteins for future functional and structural studies. caffeine | paraquat | salt tolerance | yeast

  4. Targeted Overexpression of Amelotin Disrupts the Microstructure of Dental Enamel

    OpenAIRE

    Lacruz, Rodrigo S.; Yohei Nakayama; James Holcroft; Van, Nguyen.; Eszter Somogyi-Ganss; Snead, Malcolm L.; WHITE, Shane N.; Paine, Michael L.; Bernhard Ganss

    2012-01-01

    We have previously identified amelotin (AMTN) as a novel protein expressed predominantly during the late stages of dental enamel formation, but its role during amelogenesis remains to be determined. In this study we generated transgenic mice that produce AMTN under the amelogenin (Amel) gene promoter to study the effect of AMTN overexpression on enamel formation in vivo. The specific overexpression of AMTN in secretory stage ameloblasts was confirmed by Western blot and immunohistochemistry. ...

  5. Targeted overexpression of amelotin disrupts the microstructure of dental enamel.

    Directory of Open Access Journals (Sweden)

    Rodrigo S Lacruz

    Full Text Available We have previously identified amelotin (AMTN as a novel protein expressed predominantly during the late stages of dental enamel formation, but its role during amelogenesis remains to be determined. In this study we generated transgenic mice that produce AMTN under the amelogenin (Amel gene promoter to study the effect of AMTN overexpression on enamel formation in vivo. The specific overexpression of AMTN in secretory stage ameloblasts was confirmed by Western blot and immunohistochemistry. The gross histological appearance of ameloblasts or supporting cellular structures as well as the expression of the enamel proteins amelogenin (AMEL and ameloblastin (AMBN was not altered by AMTN overexpression, suggesting that protein production, processing and secretion occurred normally in transgenic mice. The expression of Odontogenic, Ameloblast-Associated (ODAM was slightly increased in secretory stage ameloblasts of transgenic animals. The enamel in AMTN-overexpressing mice was much thinner and displayed a highly irregular surface structure compared to wild type littermates. Teeth of transgenic animals underwent rapid attrition due to the brittleness of the enamel layer. The microstructure of enamel, normally a highly ordered arrangement of hydroxyapatite crystals, was completely disorganized. Tomes' process, the hallmark of secretory stage ameloblasts, did not form in transgenic mice. Collectively our data demonstrate that the overexpression of amelotin has a profound effect on enamel structure by disrupting the formation of Tomes' process and the orderly growth of enamel prisms.

  6. Targeted overexpression of amelotin disrupts the microstructure of dental enamel.

    Science.gov (United States)

    Lacruz, Rodrigo S; Nakayama, Yohei; Holcroft, James; Nguyen, Van; Somogyi-Ganss, Eszter; Snead, Malcolm L; White, Shane N; Paine, Michael L; Ganss, Bernhard

    2012-01-01

    We have previously identified amelotin (AMTN) as a novel protein expressed predominantly during the late stages of dental enamel formation, but its role during amelogenesis remains to be determined. In this study we generated transgenic mice that produce AMTN under the amelogenin (Amel) gene promoter to study the effect of AMTN overexpression on enamel formation in vivo. The specific overexpression of AMTN in secretory stage ameloblasts was confirmed by Western blot and immunohistochemistry. The gross histological appearance of ameloblasts or supporting cellular structures as well as the expression of the enamel proteins amelogenin (AMEL) and ameloblastin (AMBN) was not altered by AMTN overexpression, suggesting that protein production, processing and secretion occurred normally in transgenic mice. The expression of Odontogenic, Ameloblast-Associated (ODAM) was slightly increased in secretory stage ameloblasts of transgenic animals. The enamel in AMTN-overexpressing mice was much thinner and displayed a highly irregular surface structure compared to wild type littermates. Teeth of transgenic animals underwent rapid attrition due to the brittleness of the enamel layer. The microstructure of enamel, normally a highly ordered arrangement of hydroxyapatite crystals, was completely disorganized. Tomes' process, the hallmark of secretory stage ameloblasts, did not form in transgenic mice. Collectively our data demonstrate that the overexpression of amelotin has a profound effect on enamel structure by disrupting the formation of Tomes' process and the orderly growth of enamel prisms.

  7. Temporal Effects of Catalase Overexpression on Healing Following Myocardial Infarction

    Science.gov (United States)

    Pendergrass, Karl D.; Varghese, Susan T.; Maiellaro-Rafferty, Kathryn; Brown, Milton E.; Taylor, W. Robert; Davis, Michael E.

    2011-01-01

    Background Reactive oxygen species, such as hydrogen peroxide (H2O2), contribute to progression of dysfunction following myocardial infarction (MI). However, chronic overexpression studies do not agree with acute protein delivery studies. The purpose of the present study was to assess the temporal role of cardiomyocyte-derived H2O2 scavenging on cardiac function after infarction using an inducible system. Methods and Results We developed a tamoxifen-inducible, cardiomyocyte-specific catalase overexpressing mouse. Catalase overexpression was induced either 5 days pre or post-MI. Mice exhibited a 3-fold increase in cardiac catalase activity that was associated with a significant decrease in H2O2 levels at both 7 and 21 days. However, cardiac function improved only at the later time point. Pro-inflammatory and fibrotic genes were acutely upregulated after MI, but catalase overexpression abolished the increase, despite no acute change in function. This led to reduced overall scar formation, with lower levels of Collagen 1A and increased contractile Collagen 3A expression at 21 days. Conclusions In contrast to prior studies, there were no acute functional improvements with physiological catalase overexpression prior to MI. Scavenging of H2O2 however, reduced pro-inflammatory cytokines and altered cardiac collagen isoforms, associated with an improvement in cardiac function after 21 days. Our results suggest that sustained H2O2 levels, rather than acute levels immediately following MI, may be critical in directing remodeling and cardiac function at later time points. PMID:20971939

  8. Autotaxin overexpression causes embryonic lethality and vascular defects.

    Directory of Open Access Journals (Sweden)

    Hiroshi Yukiura

    Full Text Available Autotaxin (ATX is a secretory protein, which converts lysophospholipids to lysophosphatidic acid (LPA, and is essential for embryonic vascular formation. ATX is abundantly detected in various biological fluids and its level is elevated in some pathophysiological conditions. However, the roles of elevated ATX levels remain to be elucidated. In this study, we generated conditional transgenic (Tg mice overexpressing ATX and examined the effects of excess LPA signalling. We found that ATX overexpression in the embryonic period caused severe vascular defects and was lethal around E9.5. ATX was conditionally overexpressed in the neonatal period using the Cre/loxP system, which resulted in a marked increase in the plasma LPA level. This resulted in retinal vascular defects including abnormal vascular plexus and increased vascular regression. Our findings indicate that the ATX level must be carefully regulated to ensure coordinated vascular formation.

  9. Autotaxin Overexpression Causes Embryonic Lethality and Vascular Defects

    Science.gov (United States)

    Yukiura, Hiroshi; Kano, Kuniyuki; Kise, Ryoji; Inoue, Asuka; Aoki, Junken

    2015-01-01

    Autotaxin (ATX) is a secretory protein, which converts lysophospholipids to lysophosphatidic acid (LPA), and is essential for embryonic vascular formation. ATX is abundantly detected in various biological fluids and its level is elevated in some pathophysiological conditions. However, the roles of elevated ATX levels remain to be elucidated. In this study, we generated conditional transgenic (Tg) mice overexpressing ATX and examined the effects of excess LPA signalling. We found that ATX overexpression in the embryonic period caused severe vascular defects and was lethal around E9.5. ATX was conditionally overexpressed in the neonatal period using the Cre/loxP system, which resulted in a marked increase in the plasma LPA level. This resulted in retinal vascular defects including abnormal vascular plexus and increased vascular regression. Our findings indicate that the ATX level must be carefully regulated to ensure coordinated vascular formation PMID:25992708

  10. Matrix metalloproteinase-8 overexpression prevents proper tissue repair

    DEFF Research Database (Denmark)

    Danielsen, Patricia Louise; Holst, Anders V; Maltesen, Henrik R

    2011-01-01

    The collagenolytic matrix metalloproteinase-8 (MMP-8) is essential for normal tissue repair but is often overexpressed in wounds with disrupted healing. Our aim was to study the impact of a local excess of this neutrophil-derived proteinase on wound healing using recombinant adenovirus-driven tra......The collagenolytic matrix metalloproteinase-8 (MMP-8) is essential for normal tissue repair but is often overexpressed in wounds with disrupted healing. Our aim was to study the impact of a local excess of this neutrophil-derived proteinase on wound healing using recombinant adenovirus...

  11. Tobacco, alcohol, and p53 overexpression in early colorectal neoplasia

    Directory of Open Access Journals (Sweden)

    Mansukhani Mahesh

    2003-11-01

    Full Text Available Abstract Background The p53 tumor suppressor gene is commonly mutated in colorectal cancer. While the effect of p53 mutations on colorectal cancer prognosis has been heavily studied, less is known about how epidemiologic risk factors relate to p53 status, particularly in early colorectal neoplasia prior to clinically invasive colorectal cancer (including adenomas, carcinoma in situ (CIS, and intramucosal carcinoma. Methods We examined p53 status, as measured by protein overexpression, in 157 cases with early colorectal neoplasia selected from three New York City colonoscopy clinics. After collecting paraffin-embedded tissue blocks, immunohistochemistry was performed using an anti-p53 monoclonal mouse IgG2a [BP53-12-1] antibody. We analyzed whether p53 status was different for risk factors for colorectal neoplasia relative to a polyp-free control group (n = 508. Results p53 overexpression was found in 10.3%, 21.7%, and 34.9%, of adenomatous polyps, CIS, and intramucosal cases, respectively. Over 90% of the tumors with p53 overexpression were located in the distal colon and rectum. Heavy cigarette smoking (30+ years was associated with cases not overexpressing p53 (OR = 1.8, 95% CI = 1.1–2.9 but not with those cases overexpressing p53 (OR = 1.0, 95% CI = 0.4–2.6. Heavy beer consumption (8+ bottles per week was associated with cases overexpressing p53 (OR = 4.0, 95% CI = 1.3–12.0 but not with cases without p53 overexpression (OR = 1.6, 95% CI = 0.7–3.7. Conclusion Our findings that p53 overexpression in early colorectal neoplasia may be positively associated with alcohol intake and inversely associated with cigarette smoking are consistent with those of several studies of p53 expression and invasive cancer, and suggest that there may be relationships of smoking and alcohol with p53 early in the adenoma to carcinoma sequence.

  12. Role of overexpressed CFA/I fimbriae in bacterial swimming

    OpenAIRE

    Cao, Ling; Suo, Zhiyong; Lim, Timothy; Jun, SangMu; Deliorman, Muhammedin; Riccardi, Carol; Kellerman, Laura; Avci, Recep; Yang, Xinghong

    2012-01-01

    Enterotoxigenic Escherichia coli CFA/I is a protective antigen and has been overexpressed in bacterial vectors, such as Salmonella Typhimurium H683, to generate vaccines. Effects that overexpressed CFA/I may engender on the bacterial host remain largely unexplored. To investigate, we constructed a high CFA/I expression strain, H683-pC2, and compared it to a low CFA/I expression strain, H683-pC, and to a non-CFA/I expression strain, H683-pY. The results showed that H683-pC2 was less able to mi...

  13. Macrophages overexpressing Aire induce CD4+Foxp3+ T cells.

    Science.gov (United States)

    Sun, Jitong; Fu, Haiying; Wu, Jing; Zhu, Wufei; Li, Yi; Yang, Wei

    2013-01-01

    Aire plays an important role in central immune tolerance by regulating the transcription of thousands of genes. However, the role of Aire in the peripheral immune system is poorly understood. Regulatory T (Treg) cells are considered essential for the maintenance of peripheral tolerance, but the effect of Aire on Treg cells in the peripheral immune system is currently unknown. In this study, we investigated the effects of macrophages overexpressing Aire on CD4+Foxp3+ Treg cells by co-culturing Aire-overexpressing RAW264.7 cells or their supernatant with splenocytes. The results show that macrophages overexpressing Aire enhanced the expression of Foxp3 mRNA and induced different subsets of Treg cells in splenocytes through cell-cell contact or a co-culture supernatants. TGF-β is a key molecule in the increases of CD4+CD45RA+Foxp3hi T cell and activating Treg (aTreg) levels observed following cell‑supernatant co-culturing. Subsets of Treg cells were induced by Aire-overexpressing macrophages, and the manipulation of Treg cells by the targeting of Aire may provide a method for the treatment of inflammatory or autoimmune diseases.

  14. Improvement of daptomycin yield by overexpression of the ...

    African Journals Online (AJOL)

    The effects of the accessory genes flanking the non-ribosomal peptide synthetase (NRPS) genes on daptomycin production were investigated by overexpression under the control of ermE* promoter via the integrative Escherichia coli–Streptomyces vector pIB139. The yield of daptomycin was promoted significantly when ...

  15. Immunohistochemical detection of Her-2/neu overexpression in ...

    African Journals Online (AJOL)

    Immunohistochemical detection of Her-2/neu overexpression in breast carcinoma in Nigerians: A 5-year retrospective study. ... cases of invasive lobular carcinoma (10.8%), three cases of medullary carcinoma (3.6%), two cases of papillary carcinoma (2.4%), and a case each of mucinous and clear cell carcinoma (1.2%).

  16. Optimization of membrane protein overexpression and purification using GFP fusions

    NARCIS (Netherlands)

    Drew, David; Lerch, Mirjam; Kunji, Edmund; Slotboom, Dirk-Jan; de Gier, Jan-Willem

    Optimizing conditions for the overexpression and purification of membrane proteins for functional and structural studies is usually a Laborious and time-consuming process. This process can be accelerated using membrane protein-GFP fusions(1-3), which allows direct monitoring and visualization of

  17. Control of cellulose biosynthesis by overexpression of a transcription factor

    Energy Technology Data Exchange (ETDEWEB)

    Han, Kyung-Hwan; Ko, Jae-Heung; Kim, Won-Chan; Kim; , Joo-Yeol

    2017-05-16

    The invention relates to the over-expression of a transcription factor selected from the group consisting of MYB46, HAM1, HAM2, MYB112, WRKY11, ERF6, and any combination thereof in a plant, which can modulate and thereby modulating the cellulose content of the plant.

  18. Brain phenotype of transgenic mice overexpressing cystathionine β-synthase.

    Directory of Open Access Journals (Sweden)

    Vinciane Régnier

    Full Text Available The cystathionine β-synthase (CBS gene, located on human chromosome 21q22.3, is a good candidate for playing a role in the Down Syndrome (DS cognitive profile: it is overexpressed in the brain of individuals with DS, and it encodes a key enzyme of sulfur-containing amino acid (SAA metabolism, a pathway important for several brain physiological processes.Here, we have studied the neural consequences of CBS overexpression in a transgenic mouse line (60.4P102D1 expressing the human CBS gene under the control of its endogenous regulatory regions. These mice displayed a ∼2-fold increase in total CBS proteins in different brain areas and a ∼1.3-fold increase in CBS activity in the cerebellum and the hippocampus. No major disturbance of SAA metabolism was observed, and the transgenic mice showed normal behavior in the rotarod and passive avoidance tests. However, we found that hippocampal synaptic plasticity is facilitated in the 60.4P102D1 line.We demonstrate that CBS overexpression has functional consequences on hippocampal neuronal networks. These results shed new light on the function of the CBS gene, and raise the interesting possibility that CBS overexpression might have an advantageous effect on some cognitive functions in DS.

  19. Improvement of daptomycin yield by overexpression of the ...

    African Journals Online (AJOL)

    enoh

    2012-03-20

    Mar 20, 2012 ... Key words: Daptomycin production, accessory genes of NRPS, overexpression, Streptomyces roseosporus. INTRODUCTION. Daptomycin is a ... involving a binding action to bacteria cell membranes, which may account for its ... amino acids precursors of 3-methyl-glutamic acid. (3mGlu) and kynurenine ...

  20. Constitutive overexpression of muscarinic receptors leads to vagal hyperreactivity.

    Directory of Open Access Journals (Sweden)

    Angelo Livolsi

    Full Text Available BACKGROUND: Alterations in muscarinic receptor expression and acetylcholinesterase (AchE activity have been observed in tissues from Sudden Infant Death Syndrome (SIDS. Vagal overactivity has been proposed as a possible cause of SIDS as well as of vasovagal syncopes. The aim of the present study was to seek whether muscarinic receptor overexpression may be the underlying mechanism of vagal hyperreactivity. Rabbits with marked vagal pauses following injection of phenylephrine were selected and crossed to obtain a vagal hyperreactive strain. The density of cardiac muscarinic receptors and acetylcholinesterase (AchE gene expression were assessed. Blood markers of the observed cardiac abnormalities were also sought. METHODOLOGY/PRINCIPAL FINDINGS: Cardiac muscarinic M(2 and M(3 receptors were overexpressed in hyperreactive rabbits compared to control animals (2.3-fold and 2.5-fold, respectively and the severity of the phenylephrine-induced bradycardia was correlated with their densities. A similar overexpression of M(2 receptors was observed in peripheral mononuclear white blood cells, suggesting that cardiac M(2 receptor expression can be inferred with high confidence from measurements in blood cells. Sequencing of the coding fragment of the M(2 receptor gene revealed a single nucleotide mutation in 83% of hyperreactive animals, possibly contributing for the transcript overexpression. Significant increases in AchE expression and activity were also assessed (AchE mRNA amplification ratio of 3.6 versus normal rabbits. This phenomenon might represent a compensatory consequence of muscarinic receptors overexpression. Alterations in M(2 receptor and AchE expression occurred between the 5th and the 7th week of age, a critical period also characterized by a higher mortality rate of hyperreactive rabbits (52% in H rabbits versus 13% in normal rabbits and preceeded the appearance of functional disorders. CONCLUSIONS/SIGNIFICANCE: The results suggest that

  1. Nmdmc overexpression extends Drosophila lifespan and reduces levels of mitochondrial reactive oxygen species

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Suyeun [Department of Preventive Medicine, College of Medicine, Korea University, 73 Inchon-ro, Seongbuk-gu, Seoul 136-705 (Korea, Republic of); Jang, Yeogil; Paik, Donggi [Department of Physiology, College of Medicine, Korea University, 73 Inchon-ro, Seongbuk-gu, Seoul 136-705 (Korea, Republic of); Lee, Eunil, E-mail: eunil@korea.ac.kr [Department of Preventive Medicine, College of Medicine, Korea University, 73 Inchon-ro, Seongbuk-gu, Seoul 136-705 (Korea, Republic of); Park, Joong-Jean, E-mail: parkjj@korea.ac.kr [Department of Physiology, College of Medicine, Korea University, 73 Inchon-ro, Seongbuk-gu, Seoul 136-705 (Korea, Republic of)

    2015-10-02

    NAD-dependent methylenetetrahydrofolate dehydrogenase-methenyltetrahydrofolate cyclohydrolase (NMDMC) is a bifunctional enzyme involved in folate-dependent metabolism and highly expressed in rapidly proliferating cells. However, Nmdmc physiological roles remain unveiled. We found that ubiquitous Nmdmc overexpression enhanced Drosophila lifespan and stress resistance. Interestingly, Nmdmc overexpression in the fat body was sufficient to increase lifespan and tolerance against oxidative stress. In addition, these conditions coincided with significant decreases in the levels of mitochondrial ROS and Hsp22 as well as with a significant increase in the copy number of mitochondrial DNA. These results suggest that Nmdmc overexpression should be beneficial for mitochondrial homeostasis and increasing lifespan. - Highlights: • Ubiquitous Nmdmc overexpression enhanced lifespan and stress tolerance. • Nmdmc overexpression in the fat body extended longevity. • Fat body-specific Nmdmc overexpression increased oxidative stress resistance. • Nmdmc overexpression decreased Hsp22 transcript levels and ROS. • Nmdmc overexpression increased mitochondrial DNA copy number.

  2. Role of overexpressed CFA/I fimbriae in bacterial swimming.

    Science.gov (United States)

    Cao, Ling; Suo, Zhiyong; Lim, Timothy; Jun, Sangmu; Deliorman, Muhammedin; Riccardi, Carol; Kellerman, Laura; Avci, Recep; Yang, Xinghong

    2012-06-01

    Enterotoxigenic Escherichia coli CFA/I is a protective antigen and has been overexpressed in bacterial vectors, such as Salmonella Typhimurium H683, to generate vaccines. Effects that overexpressed CFA/I may engender on the bacterial host remain largely unexplored. To investigate, we constructed a high CFA/I expression strain, H683-pC2, and compared it to a low CFA/I expression strain, H683-pC, and to a non-CFA/I expression strain, H683-pY. The results showed that H683-pC2 was less able to migrate into semisolid agar (0.35%) than either H683-pC or H683-pY. Bacteria that migrated showed motility halo sizes of H683-pC2 CFA/I fimbriae on bacterial swimming motility.

  3. Overexpression of esterase D in kidney from trisomy 13 fetuses

    Energy Technology Data Exchange (ETDEWEB)

    Loughna, S.; Moore, G. (Institute of Obstetrics and Gynaecology, London (United Kingdom)); Gau, G.; Blunt, S. (Cytogenetics Lab., London (United Kingdom)); Nicolaides, K. (King' s College School of Medicine and Dentistry, London (United Kingdom))

    1993-10-01

    Human trisomy 13 (Patau syndrome) occurs in approximately 1 in 5,000 live births. It is compatible with life, but prolonged survival is rare. Anomalies often involve the urogenital, cardiac, craniofacial, and central nervous systems. It is possible that these abnormalities may be due to the overexpression of developmentally important genes on chromosome 13. The expression of esterase D (localized to chromosome 13q14.11) has been investigated in both muscle and kidney from trisomy 13 fetuses and has been compared with normal age- and sex-matched fetal tissues, by using northern analysis. More than a twofold increase in expression of esterase D was found in the kidney of two trisomy 13 fetuses, with normal levels in a third. Overexpression was not seen in the muscle tissues from these fetuses. 34 refs., 3 figs., 2 tabs.

  4. Overexpression of esterase D in kidney from trisomy 13 fetuses.

    Science.gov (United States)

    Loughna, S; Bennett, P; Gau, G; Nicolaides, K; Blunt, S; Moore, G

    1993-01-01

    Human trisomy 13 (Patau syndrome) occurs in approximately 1 in 5,000 live births. It is compatible with life, but prolonged survival is rare. Anomalies often involve the urogenital, cardiac, craniofacial, and central nervous systems. It is possible that these abnormalities may be due to the overexpression of developmentally important genes on chromosome 13. The expression of esterase D (localized to chromosome 13q14.11) has been investigated in both muscle and kidney from trisomy 13 fetuses and has been compared with normal age- and sex-matched fetal tissues, by using northern analysis. More than a twofold increase in expression of esterase D was found in the kidney of two trisomy 13 fetuses, with normal levels in a third. Overexpression was not seen in the muscle tissues from these fetuses. Images Figure 1 Figure 2 Figure 3 PMID:8213811

  5. Odontoblast-targeted Bcl-2 Overexpression Impairs Dentin Formation

    Science.gov (United States)

    Zhang, Wenjian; Ju, Jun; Gronowicz, Gloria.

    2010-01-01

    Apoptosis has been described extensively in tooth development, which is under tight control of multiple apoptosis regulators, including anti-apoptotic protein Bcl-2. However, it is totally unclear how Bcl-2 is related to odontogenesis, especially dentinogenesis. Using a transgenic mouse Col2.3Bcl-2 in which human Bcl-2 was overexpressed in odontoblasts, the effect of Bcl-2 on dentinogenesis was investigated. Overexpression of Bcl-2 was detected by immunohistochemistry and Western blot. Odontoblast apoptosis was evaluated by TUNEL and Western blot detection of cleaved caspase-3. Odontoblast differentiation was assessed by real-time PCR detection of dentin matrix expression. Dentin mineralization was evaluated by micro-CT in vivo, and alizarin red S staining and calcium content analysis in vitro. Bcl-2 was found to be overexpressed in odontoblasts and prevent their apoptosis. Odontoblast differentiation and mineralization was inhibited by Bcl-2, as evidenced by lower expressions of DMP-1, OC, and DSPP, and decreased odontoblast mineralization in vitro, as well as decreased dentin thickness and mineral density in vivo when compared to the wild type animals. Inhibition of odontoblast differentiation by Bcl-2 occurs, at least partially, via a suppression of MEK-ERK1/2 signaling pathway. In conclusion, Bcl-2 overexpression prevents odontoblast apoptosis and impairs dentin formation, partially via an inhibition of odontoblast differentiation. This study revealed some novel functions of Bcl-2 in dentinogenesis in addition to its anti-apoptotic effect, which shed some light on the genetic complexity of tooth development. PMID:20518070

  6. Overexpression of Lamin B Receptor Results in Impaired Skin Differentiation.

    Directory of Open Access Journals (Sweden)

    Agustín Sola Carvajal

    Full Text Available Hutchinson-Gilford progeria syndrome (HGPS is a rare segmental progeroid disorder commonly caused by a point mutation in the LMNA gene that results in the increased activation of an intra-exonic splice site and the production of a truncated lamin A protein, named progerin. In our previous work, induced murine epidermal expression of this specific HGPS LMNA mutation showed impaired keratinocyte differentiation and upregulated lamin B receptor (LBR expression in suprabasal keratinocytes. Here, we have developed a novel transgenic animal model with induced overexpression of LBR in the interfollicular epidermis. LBR overexpression resulted in epidermal hypoplasia, along with the downregulation and mislocalization of keratin 10, suggesting impaired keratinocyte differentiation. Increased LBR expression in basal and suprabasal cells did not coincide with increased proliferation. Similar to our previous report of HGPS mice, analyses of γH2AX, a marker of DNA double-strand breaks, revealed an increased number of keratinocytes with multiple foci in LBR-overexpressing mice compared with wild-type mice. In addition, suprabasal LBR-positive cells showed densely condensed and peripherally localized chromatin. Our results show a moderate skin differentiation phenotype, which indicates that upregulation of LBR is not the sole contributor to the HGPS phenotype.

  7. Neuroligin-1 overexpression in newborn granule cells in vivo.

    Directory of Open Access Journals (Sweden)

    Eric Schnell

    Full Text Available Adult-born dentate granule cells integrate into the hippocampal network, extend neurites and form synapses in otherwise mature tissue. Excitatory and inhibitory inputs innervate these new granule cells in a stereotyped, temporally segregated manner, which presents a unique opportunity to study synapse development in the adult brain. To examine the role of neuroligins as synapse-inducing molecules in vivo, we infected dividing neural precursors in adult mice with a retroviral construct that increased neuroligin-1 levels during granule cell differentiation. By 21 days post-mitosis, exogenous neuroligin-1 was expressed at the tips of dendritic spines and increased the number of dendritic spines. Neuroligin-1-overexpressing cells showed a selective increase in functional excitatory synapses and connection multiplicity by single afferent fibers, as well as an increase in the synaptic AMPA/NMDA receptor ratio. In contrast to its synapse-inducing ability in vitro, neuroligin-1 overexpression did not induce precocious synapse formation in adult-born neurons. However, the dendrites of neuroligin-1-overexpressing cells did have more thin protrusions during an early period of dendritic outgrowth, suggesting enhanced filopodium formation or stabilization. Our results indicate that neuroligin-1 expression selectively increases the degree, but not the onset, of excitatory synapse formation in adult-born neurons.

  8. Overexpression of the riboflavin biosynthetic pathway in Pichia pastoris

    Directory of Open Access Journals (Sweden)

    Mattanovich Diethard

    2008-07-01

    Full Text Available Abstract Background High cell density cultures of Pichia pastoris grown on methanol tend to develop yellow colored supernatants, attributed to the release of free flavins. The potential of P. pastoris for flavin overproduction is therefore given, but not pronounced when the yeast is grown on glucose. The aim of this study is to characterize the relative regulatory impact of each riboflavin synthesis gene. Deeper insight into pathway control and the potential of deregulation is established by overexpression of the single genes as well as a combined deregulation of up to all six riboflavin synthesis genes. Results Overexpression of the first gene of the riboflavin biosynthetic pathway (RIB1 is already sufficient to obtain yellow colonies and the accumulation of riboflavin in the supernatant of shake flask cultures growing on glucose. Sequential deregulation of all the genes, by exchange of their native promoter with the strong and constitutive glyceraldehyde-3-phosphate dehydrogenase promoter (PGAP increases the riboflavin accumulation significantly. Conclusion The regulation of the pathway is distributed over more than one gene. High cell density cultivations of a P. pastoris strain overexpressing all six RIB genes allow the accumulation of 175 mg/L riboflavin in the supernatant. The basis for rational engineering of riboflavin production in P. pastoris has thus been established.

  9. Impact of Adiponectin Overexpression on Allergic Airways Responses in Mice

    Directory of Open Access Journals (Sweden)

    Norah G. Verbout

    2013-01-01

    Full Text Available Obesity is an important risk factor for asthma. Obese individuals have decreased circulating adiponectin, an adipose-derived hormone with anti-inflammatory properties. We hypothesized that transgenic overexpression of adiponectin would attenuate allergic airways inflammation and mucous hyperplasia in mice. To test this hypothesis, we used mice overexpressing adiponectin (Adipo Tg. Adipo Tg mice had marked increases in both serum adiponectin and bronchoalveolar lavage (BAL fluid adiponectin. Both acute and chronic ovalbumin (OVA sensitization and challenge protocols were used. In both protocols, OVA-induced increases in total BAL cells were attenuated in Adipo Tg versus WT mice. In the acute protocol, OVA-induced increases in several IL-13 dependent genes were attenuated in Adipo Tg versus WT mice, even though IL-13 per se was not affected. With chronic exposure, though OVA-induced increases in goblet cells numbers per millimeter of basement membrane were greater in Adipo Tg versus WT mice, mRNA abundance of mucous genes in lungs was not different. Also, adiponectin overexpression did not induce M2 polarization in alveolar macrophages. Our results indicate that adiponectin protects against allergen-induced inflammatory cell recruitment to the airspaces, but not development of goblet cell hyperplasia.

  10. Overexpression of Lamin B Receptor Results in Impaired Skin Differentiation.

    Science.gov (United States)

    Sola Carvajal, Agustín; McKenna, Tomás; Wallén Arzt, Emelie; Eriksson, Maria

    2015-01-01

    Hutchinson-Gilford progeria syndrome (HGPS) is a rare segmental progeroid disorder commonly caused by a point mutation in the LMNA gene that results in the increased activation of an intra-exonic splice site and the production of a truncated lamin A protein, named progerin. In our previous work, induced murine epidermal expression of this specific HGPS LMNA mutation showed impaired keratinocyte differentiation and upregulated lamin B receptor (LBR) expression in suprabasal keratinocytes. Here, we have developed a novel transgenic animal model with induced overexpression of LBR in the interfollicular epidermis. LBR overexpression resulted in epidermal hypoplasia, along with the downregulation and mislocalization of keratin 10, suggesting impaired keratinocyte differentiation. Increased LBR expression in basal and suprabasal cells did not coincide with increased proliferation. Similar to our previous report of HGPS mice, analyses of γH2AX, a marker of DNA double-strand breaks, revealed an increased number of keratinocytes with multiple foci in LBR-overexpressing mice compared with wild-type mice. In addition, suprabasal LBR-positive cells showed densely condensed and peripherally localized chromatin. Our results show a moderate skin differentiation phenotype, which indicates that upregulation of LBR is not the sole contributor to the HGPS phenotype.

  11. Role of overexpressed CFA/I fimbriae in bacterial swimming

    Science.gov (United States)

    Cao, Ling; Suo, Zhiyong; Lim, Timothy; Jun, SangMu; Deliorman, Muhammedin; Riccardi, Carol; Kellerman, Laura; Avci, Recep

    2012-01-01

    Enterotoxigenic Escherichia coli CFA/I is a protective antigen and has been overexpressed in bacterial vectors, such as Salmonella Typhimurium H683, to generate vaccines. Effects that overexpressed CFA/I may engender on the bacterial host remain largely unexplored. To investigate, we constructed a high CFA/I expression strain, H683-pC2, and compared it to a low CFA/I expression strain, H683-pC, and to a non-CFA/I expression strain, H683-pY. The results showed that H683-pC2 was less able to migrate into semisolid agar (0.35%) than either H683-pC or H683-pY. Bacteria that migrated showed motility halo sizes of H683-pC2 < H683-pC < H683-pY. In the liquid culture media, H683-pC2 cells precipitated to the bottom of the tube, while those of H683-pY did not. In situ imaging revealed that H683-pC2 bacilli tended to auto-agglutinate within the semisolid agar, while H683-pY bacilli did not. When the cfaBE fimbrial fiber encoding genes were deleted from pC2, the new plasmid, pC2(−), significantly recovered bacterial swimming capability. Our study highlights the negative impact of overexpressed CFA/I fimbriae on bacterial swimming motility. PMID:22562964

  12. Oncoprotein MDM2 Overexpression is Associated with Poor Prognosis in Distinct Non-Hodgkin's Lymphoma Entities

    DEFF Research Database (Denmark)

    Møller, Michael Boe; Nielsen, O; Pedersen, Niels Tinggaard

    1999-01-01

    overexpression was present in 42 (22%) of 188 cases. The frequency was highest in aggressive/very aggressive NHL (P associated with higher-grade disease (P = .008). MDM2 overexpression was not related to a phenotype indicating...... altered p53. In univariate analysis MDM2 overexpression associated with short survival in follicle center lymphomas (P = .0256), extranodal marginal zone lymphomas (P

  13. Anti-proliferative activity of the quassinoid NBT-272 in childhood medulloblastoma cells.

    Science.gov (United States)

    von Bueren, André O; Shalaby, Tarek; Rajtarova, Julia; Stearns, Duncan; Eberhart, Charles G; Helson, Lawrence; Arcaro, Alexandre; Grotzer, Michael A

    2007-01-25

    With current treatment strategies, nearly half of all medulloblastoma (MB) patients die from progressive tumors. Accordingly, the identification of novel therapeutic strategies remains a major goal. Deregulation of c-MYC is evident in numerous human cancers. In MB, over-expression of c-MYC has been shown to correlate with anaplasia and unfavorable prognosis. In neuroblastoma--an embryonal tumor with biological similarities to MB--the quassinoid NBT-272 has been demonstrated to inhibit cellular proliferation and to down-regulate c-MYC protein expression. To study MB cell responses to NBT-272 and their dependence on the level of c-MYC expression, DAOY (wild-type, empty vector transfected or c-MYC transfected), D341 (c-MYC amplification) and D425 (c-MYC amplification) human MB cells were used. The cells were treated with different concentrations of NBT-272 and the impact on cell proliferation, apoptosis and c-MYC expression was analyzed. NBT-272 treatment resulted in a dose-dependent inhibition of cellular proliferation (IC50 in the range of 1.7-9.6 ng/ml) and in a dose-dependent increase in apoptotic cell death in all human MB cell lines tested. Treatment with NBT-272 resulted in up to 90% down-regulation of c-MYC protein, as demonstrated by Western blot analysis, and in a significant inhibition of c-MYC binding activity. Anti-proliferative effects were slightly more prominent in D341 and D425 human MB cells with c-MYC amplification and slightly more pronounced in c-MYC over-expressing DAOY cells compared to DAOY wild-type cells. Moreover, treatment of synchronized cells by NBT-272 induced a marked cell arrest at the G1/S boundary. In human MB cells, NBT-272 treatment inhibits cellular proliferation at nanomolar concentrations, blocks cell cycle progression, induces apoptosis, and down-regulates the expression of the oncogene c-MYC. Thus, NBT-272 may represent a novel drug candidate to inhibit proliferation of human MB cells in vivo.

  14. Smad2 overexpression enhances adhesion of gingival epithelial cells.

    Science.gov (United States)

    Hongo, Shoichi; Yamamoto, Tadashi; Yamashiro, Keisuke; Shimoe, Masayuki; Tomikawa, Kazuya; Ugawa, Yuki; Kochi, Shinsuke; Ideguchi, Hidetaka; Maeda, Hiroshi; Takashiba, Shogo

    2016-11-01

    Gingival epithelial cells play an important role in preventing the initiation of periodontitis, by their hemidesmosomal adhesion to the tooth root surface. Adhesion requires integrin-extracellular matrix (ECM) interactions that are intricately regulated by transforming growth factor-β (TGF-β) signaling. However, the mechanisms underlying the interplay between adhesion molecules and TGF-β, especially the respective roles of Smad2 and Smad3, remain elusive. In this study, we examined the effects of Smad overexpression on gingival epithelial cell adhesion and expression profiles of integrin and ECM-related genes. Human gingival epithelial cells immortalized by the SV40 T-antigen were transfected with Smad2- and Smad3-overexpression vectors. A cell adhesion assay involving fluorescence detection of attached cells was performed using the ArrayScan imaging system. Real-time PCR was performed to examine the kinetics of integrin and ECM gene expression. In vitro and in vivo localization of adhesion molecules was examined by immunofluorescence analysis. By using SB431542, a specific inhibitor of the TGF-β type I receptor, Smad2/3 signaling was confirmed to be dominant in TGF-β1-induced cell adhesion. The Smad2-transfectant demonstrated higher potency for cell adhesion and integrin expression (α2, α5, β4, and β6) than the Smad3-transfectant, whereas little or no change in ECM expression was observed in either transfectant. Moreover, the gingival epithelium of transgenic mice that overexpressed Smad2 driven by the keratin 14 promoter showed increased integrin α2 expression. These findings indicate the crucial role of Smad2 in increased adhesion of gingival epithelial cells via upregulation of integrin α2. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Differences in radiosensitivity between three HER2 overexpressing cell lines

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    Steffen, Ann-Charlott; Tolmachev, Vladimir; Stenerloew, Bo [Uppsala University, Unit of Biomedical Radiation Sciences, Department of Oncology, Radiology and Clinical Immunology, Rudbeck Laboratory, Uppsala (Sweden); Goestring, Lovisa [Affibody AB, Bromma (Sweden); Palm, Stig [Sahlgrenska Academy at Goeteborg University, Department of Radiation Physics, Goeteborg (Sweden); Carlsson, Joergen [Uppsala University, Unit of Biomedical Radiation Sciences, Department of Oncology, Radiology and Clinical Immunology, Rudbeck Laboratory, Uppsala (Sweden); Rudbeck Laboratory, Biomedical Radiation Sciences, Uppsala (Sweden)

    2008-06-15

    HER2 is a potential target for radionuclide therapy, especially when HER2 overexpressing breast cancer cells are resistant to Herceptin {sup registered} treatment. Therefore, it is of interest to analyse whether HER2 overexpressing tumour cells have different inherent radiosensitivity. The radiosensitivity of three often used HER2 overexpressing cell lines, SKOV-3, SKBR-3 and BT-474, was analysed. The cells were exposed to conventional photon irradiation, low linear energy transfer (LET), to characterise their inherent radiosensitivity. The analysis was made with clonogenic survival and growth extrapolation assays. The cells were also exposed to alpha particles, high LET, from {sup 211}At decays using the HER2-binding affibody molecule {sup 211}At-(Z{sub HER2:4}){sub 2} as targeting agent. Assays for studies of internalisation of the affibody molecule were applied. SKOV-3 cells were most radioresistant, SKBR-3 cells were intermediate and BT-474 cells were most sensitive as measured with the clonogenic and growth extrapolation assays after photon irradiation. The HER2 dependent cellular uptake of {sup 211}At was qualitatively similar for all three cell lines. However, the sensitivity to the alpha particles from {sup 211}At differed; SKOV-3 was most resistant, SKBR-3 intermediate and BT-474 most sensitive. These differences were unexpected because it is assumed that all types of cells should have similar sensitivity to high-LET radiation. The sensitivity to alpha particle exposure correlated with internalisation of the affibody molecule and with size of the cell nucleus. There can be differences in radiosensitivity, which, if they also exist between patient breast cancer cells, are important to consider for both conventional radiotherapy and for HER2-targeted radionuclide therapy. (orig.)

  16. Vasomotor control in mice overexpressing human endothelial nitric oxide synthase.

    Science.gov (United States)

    van Deel, Elza D; Merkus, Daphne; van Haperen, Rien; de Waard, Monique C; de Crom, Rini; Duncker, Dirk J

    2007-08-01

    Nitric oxide (NO) plays a key role in regulating vascular tone. Mice overexpressing endothelial NO synthase [eNOS-transgenic (Tg)] have a 20% lower systemic vascular resistance (SVR) than wild-type (WT) mice. However, because eNOS enzyme activity is 10 times higher in tissue homogenates from eNOS-Tg mice, this in vivo effect is relatively small. We hypothesized that the effect of eNOS overexpression is attenuated by alterations in NO signaling and/or altered contribution of other vasoregulatory pathways. In isoflurane-anesthetized open-chest mice, eNOS inhibition produced a significantly greater increase in SVR in eNOS-Tg mice compared with WT mice, consistent with increased NO synthesis. Vasodilation to sodium nitroprusside (SNP) was reduced, whereas the vasodilator responses to phosphodiesterase-5 blockade and 8-bromo-cGMP (8-Br-cGMP) were maintained in eNOS-Tg compared with WT mice, indicating blunted responsiveness of guanylyl cyclase to NO, which was supported by reduced guanylyl cyclase activity. There was no evidence of eNOS uncoupling, because scavenging of reactive oxygen species (ROS) produced even less vasodilation in eNOS-Tg mice, whereas after eNOS inhibition the vasodilator response to ROS scavenging was similar in WT and eNOS-Tg mice. Interestingly, inhibition of other modulators of vascular tone [including cyclooxygenase, cytochrome P-450 2C9, endothelin, adenosine, and Ca-activated K(+) channels] did not significantly affect SVR in either eNOS-Tg or WT mice, whereas the marked vasoconstrictor responses to ATP-sensitive K(+) and voltage-dependent K(+) channel blockade were similar in WT and eNOS-Tg mice. In conclusion, the vasodilator effects of eNOS overexpression are attenuated by a blunted NO responsiveness, likely at the level of guanylyl cyclase, without evidence of eNOS uncoupling or adaptations in other vasoregulatory pathways.

  17. BRCA1-IRIS overexpression promotes formation of aggressive breast cancers.

    Directory of Open Access Journals (Sweden)

    Yoshiko Shimizu

    Full Text Available INTRODUCTION: Women with HER2(+ or triple negative/basal-like (TN/BL breast cancers succumb to their cancer rapidly due, in part to acquired Herceptin resistance and lack of TN/BL-targeted therapies. BRCA1-IRIS is a recently discovered, 1399 residue, BRCA1 locus alternative product, which while sharing 1365 residues with the full-length product of this tumor suppressor gene, BRCA1/p220, it has oncoprotein-like properties. Here, we examine whether BRCA1-IRIS is a valuable treatment target for HER2(+ and/or TN/BL tumors. METHODOLOGY/PRINCIPAL FINDINGS: Immunohistochemical staining of large cohort of human breast tumor samples using new monoclonal anti-BRCA1-IRIS antibody, followed by correlation of BRCA1-IRIS expression with that of AKT1, AKT2, p-AKT, survivin and BRCA1/p220, tumor status and age at diagnosis. Generation of subcutaneous tumors in SCID mice using human mammary epithelial (HME cells overexpressing TERT/LT/BRCA1-IRIS, followed by comparing AKT, survivin, and BRCA1/p220 expression, tumor status and aggressiveness in these tumors to that in tumors developed using TERT/LT/Ras(V12-overexpressing HME cells. Induction of primary and invasive rat mammary tumors using the carcinogen N-methyl-N-nitrosourea (NMU, followed by analysis of rat BRCA1-IRIS and ERα mRNA levels in these tumors. High BRCA1-IRIS expression was detected in the majority of human breast tumors analyzed, which was positively correlated with that of AKT1-, AKT2-, p-AKT-, survivin, but negatively with BRCA1/p220 expression. BRCA1-IRIS-positivity induced high-grade, early onset and metastatic HER2(+ or TN/BL tumors. TERT/LT/BRCA1-IRIS overexpressing HME cells formed invasive subcutaneous tumors that express high AKT1, AKT2, p-AKT and vimentin, but no CK19, p63 or BRCA1/p220. NMU-induced primary and invasive rat breast cancers expressed high levels of rat BRCA1-IRIS mRNA but low levels of rat ERα mRNA. CONCLUSION/SIGNIFICANCE: BRCA1-IRIS overexpression triggers aggressive

  18. CREB Overexpression Ameliorates Age-related Behavioral and Biophysical Deficits

    Science.gov (United States)

    Yu, Xiao-Wen

    Age-related cognitive deficits are observed in both humans and animals. Yet, the molecular mechanisms underlying these deficits are not yet fully elucidated. In aged animals, a decrease in intrinsic excitability of pyramidal neurons from the CA1 sub-region of hippocampus is believed to contribute to age-related cognitive impairments, but the molecular mechanism(s) that modulate both these factors has yet to be identified. Increasing activity of the transcription factor cAMP response element-binding protein (CREB) in young adult rodents has been shown to facilitate cognition, and increase intrinsic excitability of their neurons. However, how CREB changes with age, and how that impacts cognition in aged animals, is not clear. Therefore, we first systematically characterized age- and training-related changes in CREB levels in dorsal hippocampus. At a remote time point after undergoing behavioral training, levels of total CREB and activated CREB (phosphorylated at S133, pCREB) were measured in both young and aged rats. We found that pCREB, but not total CREB was significantly reduced in dorsal CA1 of aged rats. Importantly, levels of pCREB were found to be positively correlated with short-term spatial memory in both young and aged rats i.e. higher pCREB in dorsal CA1 was associated with better spatial memory. These findings indicate that an age-related deficit in CREB activity may contribute to the development of age-related cognitive deficits. However, it was still unclear if increasing CREB activity would be sufficient to ameliorate age-related cognitive, and biophysical deficits. To address this question, we virally overexpressed CREB in CA1, where we found the age-related deficit. Young and aged rats received control or CREB virus, and underwent water maze training. While control aged animals exhibited deficits in long-term spatial memory, aged animals with CREB overexpression performed at levels comparable to young animals. Concurrently, aged neurons

  19. Overexpression of neurofilament H disrupts normal cell structure and function

    Science.gov (United States)

    Szebenyi, Gyorgyi; Smith, George M.; Li, Ping; Brady, Scott T.

    2002-01-01

    Studying exogenously expressed tagged proteins in live cells has become a standard technique for evaluating protein distribution and function. Typically, expression levels of experimentally introduced proteins are not regulated, and high levels are often preferred to facilitate detection. However, overexpression of many proteins leads to mislocalization and pathologies. Therefore, for normative studies, moderate levels of expression may be more suitable. To understand better the dynamics of intermediate filament formation, transport, and stability in a healthy, living cell, we inserted neurofilament heavy chain (NFH)-green fluorescent protein (GFP) fusion constructs in adenoviral vectors with tetracycline (tet)-regulated promoters. This system allows for turning on or off the synthesis of NFH-GFP at a selected time, for a defined period, in a dose-dependent manner. We used this inducible system for live cell imaging of changes in filament structure and cell shape, motility, and transport associated with increasing NFH-GFP expression. Cells with low to intermediate levels of NFH-GFP were structurally and functionally similar to neighboring, nonexpressing cells. In contrast, overexpression led to pathological alterations in both filament organization and cell function. Copyright 2002 Wiley-Liss, Inc.

  20. Overexpression of squamous cell carcinoma antigen variants in hepatocellular carcinoma.

    Science.gov (United States)

    Pontisso, P; Calabrese, F; Benvegnù, L; Lise, M; Belluco, C; Ruvoletto, M G; Marino, M; Valente, M; Nitti, D; Gatta, A; Fassina, G

    2004-02-23

    Pathogenetic mechanisms of hepatocellular carcinoma (HCC) are still unclear and new tools for diagnostic and therapeutic purposes are ongoing. We have assessed whether squamous cell carcinoma antigen (SCCA), a serpin overexpressed in neoplastic cells of epithelial origin, is also expressed in liver cancer. Squamous cell carcinoma antigen was evaluated by immunohistochemistry in 65 HCCs of different aetiology and in 20 normal livers. Proliferative activity was assessed using MIB-1 antibody. In 18 surgical samples, tumour and nontumour liver tissue was available for SCCA cDNA amplification and sequencing. Squamous cell carcinoma antigen was detected in 55 out of 65 (85%) tumour specimens, but in none of the 20 controls. In the majority of the cases, the positive signal was found in the cytoplasm of more than 50% of the hepatocytes. Low or undetectable SCCA (scoreSCCA score >or=2 (mean+/-s.d.: 2%+/-2.4 vs 7.5%+/-10.3, PSCCA1 variant (G(351) to A) was identified in five cases, while SCCA1 was revealed in six cases and SCCA2 in three cases. In conclusion, SCCA variants are overexpressed in HCC, independently of tumour aetiology. A novel SCCA1 variant has been identified in one third of liver tumours.

  1. Prothymosin α overexpression contributes to the development of pulmonary emphysema

    Science.gov (United States)

    Su, Bing-Hua; Tseng, Yau-Lin; Shieh, Gia-Shing; Chen, Yi-Cheng; Shiang, Ya-Chieh; Wu, Pensee; Li, Kuo-Jung; Yen, Te-Hsin; Shiau, Ai-Li; Wu, Chao-Liang

    2013-01-01

    Emphysema is one of the disease conditions that comprise chronic obstructive pulmonary disease. Prothymosin α transgenic mice exhibit an emphysema phenotype, but the pathophysiological role of prothymosin α in emphysema remains unclear. Here we show that prothymosin α contributes to the pathogenesis of emphysema by increasing acetylation of histones and nuclear factor-kappaB, particularly upon cigarette smoke exposure. We find a positive correlation between prothymosin α levels and the severity of emphysema in prothymosin α transgenic mice and emphysema patients. Prothymosin α overexpression increases susceptibility to cigarette smoke-induced emphysema, and cigarette smoke exposure further enhances prothymosin α expression. We show that prothymosin α inhibits the association of histone deacetylases with histones and nuclear factor-kappaB, and that prothymosin α overexpression increases expression of nuclear factor-kappaB-dependent matrix metalloproteinase 2 and matrix metalloproteinase 9, which are found in the lungs of patients with chronic obstructive pulmonary disease. These results demonstrate the clinical relevance of prothymosin α in regulating acetylation events during the pathogenesis of emphysema. PMID:23695700

  2. Overexpression of Catalase Diminishes Oxidative Cysteine Modifications of Cardiac Proteins.

    Directory of Open Access Journals (Sweden)

    Chunxiang Yao

    Full Text Available Reactive protein cysteine thiolates are instrumental in redox regulation. Oxidants, such as hydrogen peroxide (H2O2, react with thiolates to form oxidative post-translational modifications, enabling physiological redox signaling. Cardiac disease and aging are associated with oxidative stress which can impair redox signaling by altering essential cysteine thiolates. We previously found that cardiac-specific overexpression of catalase (Cat, an enzyme that detoxifies excess H2O2, protected from oxidative stress and delayed cardiac aging in mice. Using redox proteomics and systems biology, we sought to identify the cysteines that could play a key role in cardiac disease and aging. With a 'Tandem Mass Tag' (TMT labeling strategy and mass spectrometry, we investigated differential reversible cysteine oxidation in the cardiac proteome of wild type and Cat transgenic (Tg mice. Reversible cysteine oxidation was measured as thiol occupancy, the ratio of total available versus reversibly oxidized cysteine thiols. Catalase overexpression globally decreased thiol occupancy by ≥1.3 fold in 82 proteins, including numerous mitochondrial and contractile proteins. Systems biology analysis assigned the majority of proteins with differentially modified thiols in Cat Tg mice to pathways of aging and cardiac disease, including cellular stress response, proteostasis, and apoptosis. In addition, Cat Tg mice exhibited diminished protein glutathione adducts and decreased H2O2 production from mitochondrial complex I and II, suggesting improved function of cardiac mitochondria. In conclusion, our data suggest that catalase may alleviate cardiac disease and aging by moderating global protein cysteine thiol oxidation.

  3. [Effect of overexpression of transcription factor Runx2 and Osterix on osteogenic differentiation of endothelial cells].

    Science.gov (United States)

    Yang, Guang-Zheng; Zhang, Wen-Jie; Ding, Xun; Zhang, Xiang-Kai; Jiang, Xin-Quan; Zhang, Zhi-Yuan

    2017-08-01

    To explore the effect of overexpression of Runx2 and Osterix (OSX) genes on osteogenic differentiation of human umbilical vein endothelial cells (HUVECs). Overexpressed Runx2 and OSX lentiviral vectors were transfected into HUVECs respectively. The osteogenic potential of transfected cells was identified by alkaline phosphatase (ALP) staining and ALP activity. Furthermore, real time-PCR, Western blot and immunofluorescence staining were performed to detect the expression of osteogenic genes and proteins in HUVECs. GraphPad Prism 6.01 software was used for statistical analysis. Overexpression of Runx2 gene was beneficial for osteogenic differentiation of HUVECs, while overexpression of osterix gene did not show osteogenic differential potential. Moreover, overexpression of Runx2 gene in HUVECs up-regulated the gene expression level of Runx2, OSX, ALP, bone sialoprotein (BSP), osteopontin (OPN), and osteocalcin (OCN), and up-regulated protein level of OPN and OCN. Overexpression of Runx2 could promote osteogenic differentiation of HUVECs.

  4. Del-1 overexpression potentiates lung cancer cell proliferation and invasion

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung-Hwan; Kim, Dong-Young; Jing, Feifeng; Kim, Hyesoon [Department of Biomedical Sciences, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Yun, Chae-Ok [Department of Bioengineering, College of Engineering, Hanyang University, Seoul (Korea, Republic of); Han, Deok-Jong [Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Choi, Eun Young, E-mail: choieun@ulsan.ac.kr [Department of Biomedical Sciences, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    2015-12-04

    Developmental endothelial locus-1 (Del-1) is an endogenous anti-inflammatory molecule that is highly expressed in the lung and the brain and limits leukocyte migration to these tissues. We previously reported that the expression of Del-1 is positively regulated by p53 in lung endothelial cells. Although several reports have implicated the altered expression of Del-1 gene in cancer patients, little is known about its role in tumor cells. We here investigated the effect of Del-1 on the features of human lung carcinoma cells. Del-1 mRNA was found to be significantly decreased in the human lung adenocarcinoma cell lines A549 (containing wild type of p53), H1299 (null for p53) and EKVX (mutant p53), compared to in human normal lung epithelial BEAS-2B cells and MRC-5 fibroblasts. The decrease of Del-1 expression was dependent on the p53 activity in the cell lines, but not on the expression of p53. Neither treatment with recombinant human Del-1 protein nor the introduction of adenovirus expressing Del-1 altered the expression of the apoptosis regulators BAX, PUMA and Bcl-2. Unexpectedly, the adenovirus-mediated overexpression of Del-1 gene into the lung carcinoma cell lines promoted proliferation and invasion of the lung carcinoma cells, as revealed by BrdU incorporation and transwell invasion assays, respectively. In addition, overexpression of the Del-1 gene enhanced features of epithelial–mesenchymal transition (EMT), such as increasing vimentin while decreasing E-cadherin in A549 cells, and increases in the level of Slug, an EMT-associated transcription regulator. Our findings demonstrated for the first time that there are deleterious effects of high levels of Del-1 in lung carcinoma cells, and suggest that Del-1 may be used as a diagnostic or prognostic marker for cancer progression, and as a novel therapeutic target for lung carcinoma. - Highlights: • Developmental Endothelial Locus-1 (Del-1) expression is downregulated in human lung cancer cells.

  5. T Cell Integrin Overexpression as a Model of Murine Autoimmunity

    Directory of Open Access Journals (Sweden)

    Yung Raymond L.

    2003-01-01

    Full Text Available Integrin adhesion molecules have important adhesion and signaling functions. They also play a central role in the pathogenesis of many autoimmune diseases. Over the past few years we have described a T cell adoptive transfer model to investigate the role of T cell integrin adhesion molecules in the development of autoimmunity. This report summarizes the methods we used in establishing this murine model. By treating murine CD4+ T cells with DNA hypomethylating agents and by transfection we were able to test the in vitro effects of integrin overexpression on T cell autoreactive proliferation, cytotoxicity, adhesion and trafficking. Furthermore, we showed that the ability to induce in vivo autoimmunity may be unique to the integrin lymphocyte function associated antigen-1 (LFA-1.

  6. Mammary gland tumor formation in transgenic mice overexpressing stromelysin-1

    Energy Technology Data Exchange (ETDEWEB)

    Sympson, Carolyn J; Bissell, Mina J; Werb, Zena

    1995-06-01

    An intact basement membrane (BM) is essential for the proper function, differentiation and morphology of many epithelial cells. The disruption or loss of this BM occurs during normal development as well as in the disease state. To examine the importance of BM during mammary gland development in vivo, we generated transgenic mice that inappropriately express autoactivating isoforms of the matrix metalloproteinase stromelysin-1. The mammary glands from these mice are both functionally and morphologically altered throughout development. We have now documented a dramatic incidence of breast tumors in several independent lines of these mice. These data suggest that overexpression of stromelysin-1 and disruption of the BM may be a key step in the multi-step process of breast cancer.

  7. Behavioral characterization of a mouse model overexpressing DSCR1/ RCAN1

    OpenAIRE

    Mara Dierssen; Gloria Arqué; Jerome McDonald; Nuria Andreu; Carmen Martínez-Cué; Jesús Flórez; Cristina Fillat

    2011-01-01

    DSCR1/ RCAN1 is a chromosome 21 gene found to be overexpressed in the brains of Down syndrome (DS) and postulated as a good candidate to contribute to mental disability. However, even though Rcan1 knockout mice have pronounced spatial learning and memory deficits, the possible deleterious effects of its overexpression in DS are not well understood. We have generated a transgenic mouse model overexpressing DSCR1/RCAN1 in the brain and analyzed the effect of RCAN1 overexpression on cognitive fu...

  8. Odontoblast-targeted Bcl-2 Overexpression Promotes Dentin Damage Repair

    Science.gov (United States)

    Zhang, Wenjian; Ju, Jun

    2011-01-01

    Objective Bcl-2 is widely expressed in a developing tooth organ and regulates tooth morphogenesis. However, whether Bcl-2 is related to tooth damage repair is unknown yet. Using an odontoblast-targeted Bcl-2 overexpression transgenic mouse (Col2.3Bcl-2) and artificial cavity preparation as a model system, the relationship between Bcl-2 and reparative dentinogenesis is investigated in this study. Methods The odontoblastic-like cell cultures derived from mouse molar pulps were established. The expression of transgenic human Bcl-2 (hBcl-2) and endogenous mouse Bcl-2 (mBcl-2) and mouse Bax (mBax, a Bcl-2 antagonist) was detected in vivo and in vitro by Western blot and immunocytochemistry, respectively. Basal level and artificial cavity-induced odontoblast apoptosis was detected by the Deoxynucleotidyl Transferase (TdT) dUTP Nick End labeling (TUNEL) technique. Reparative dentin formation induced by artificial cavity drilled to a half dentin thickness on mesial cervical region of mandibular first molars 2, 4, and 6 weeks post-op was evaluated histologically and via micro-CT. Results The transgenic hBcl-2 was stably expressed in odontoblasts of the transgenic animals without interference with the expression of mBcl-2 and mBax. Basal level as well as artificial cavity- induced odontoblast apoptosis was prevented by the transgene. Compared to the wild type, the transgenic animals produced reparative dentin with significantly higher mineral density 6 weeks after the operation. Conclusions Bcl-2 overexpression prevents odontoblast apoptosis and promotes dentin damage repair, indicating that genetic manipulation of Bcl-2 may be a novel strategy to maintain the vitality and function of dentine-pulp complex under detrimental mechanical stimuli. PMID:21930259

  9. Overexpression of agouti protein and stress responsiveness in mice.

    Science.gov (United States)

    Harris, R B; Zhou, J; Shi, M; Redmann, S; Mynatt, R L; Ryan, D H

    2001-07-01

    Ectopic overexpression of agouti protein, an endogenous antagonist of melanocortin receptors' linked to the beta-actin promoter (BAPa) in mice, produces a phenotype of yellow coat color, Type II diabetes, obesity and increased somatic growth. Spontaneous overexpression of agouti increases stress-induced weight loss. In these experiments, other aspects of stress responsiveness were tested in 12-week-old male wild-type mice and BAPa mice. Two hours of restraint on three consecutive days produced greater increases in corticosterone and post-stress weight loss in BAPa than wild-type mice. In Experiment 2, anxiety-type behavior was measured immediately after 12 min of restraint. This mild stress did not produce many changes indicative of anxiety, but BAPa mice spent more time in the dark side of a light-dark box and less time in the open arms of an elevated plus maze than restrained wild-type mice. In a defensive withdrawal test, grooming was increased by restraint in all mice, but the duration of each event was substantially shorter in BAPa mice, possibly due to direct antagonism of the MC4-R by agouti protein. Thus, BAPa mice showed exaggerated endocrine and energetic responses to restraint stress with small differences in anxiety-type behavior compared with wild-type mice. These results are consistent with observations in other transgenic mice in which the melanocortin system is disrupted, but contrast with reports that acute blockade of central melanocortin receptors inhibits stress-induced hypophagia. Thus, the increased stress responsiveness in BAPa mice may be a developmental compensation for chronic inhibition of melanocortin receptors.

  10. Tubular overexpression of gremlin induces renal damage susceptibility in mice.

    Directory of Open Access Journals (Sweden)

    Alejandra Droguett

    Full Text Available A growing number of patients are recognized worldwide to have chronic kidney disease. Glomerular and interstitial fibrosis are hallmarks of renal progression. However, fibrosis of the kidney remains an unresolved challenge, and its molecular mechanisms are still not fully understood. Gremlin is an embryogenic gene that has been shown to play a key role in nephrogenesis, and its expression is generally low in the normal adult kidney. However, gremlin expression is elevated in many human renal diseases, including diabetic nephropathy, pauci-immune glomerulonephritis and chronic allograft nephropathy. Several studies have proposed that gremlin may be involved in renal damage by acting as a downstream mediator of TGF-β. To examine the in vivo role of gremlin in kidney pathophysiology, we generated seven viable transgenic mouse lines expressing human gremlin (GREM1 specifically in renal proximal tubular epithelial cells under the control of an androgen-regulated promoter. These lines demonstrated 1.2- to 200-fold increased GREM1 expression. GREM1 transgenic mice presented a normal phenotype and were without proteinuria and renal function involvement. In response to the acute renal damage cause by folic acid nephrotoxicity, tubule-specific GREM1 transgenic mice developed increased proteinuria after 7 and 14 days compared with wild-type treated mice. At 14 days tubular lesions, such as dilatation, epithelium flattening and hyaline casts, with interstitial cell infiltration and mild fibrosis were significantly more prominent in transgenic mice than wild-type mice. Tubular GREM1 overexpression was correlated with the renal upregulation of profibrotic factors, such as TGF-β and αSMA, and with increased numbers of monocytes/macrophages and lymphocytes compared to wild-type mice. Taken together, our results suggest that GREM1-overexpressing mice have an increased susceptibility to renal damage, supporting the involvement of gremlin in renal damage

  11. Sarcolipin overexpression improves muscle energetics and reduces fatigue

    Science.gov (United States)

    Sopariwala, Danesh H.; Pant, Meghna; Shaikh, Sana A.; Goonasekera, Sanjeewa A.; Molkentin, Jeffery D.; Weisleder, Noah; Ma, Jianjie; Pan, Zui

    2015-01-01

    Sarcolipin (SLN) is a regulator of sarcoendoplasmic reticulum calcium ATPase in skeletal muscle. Recent studies using SLN-null mice have identified SLN as a key player in muscle thermogenesis and metabolism. In this study, we exploited a SLN overexpression (SlnOE) mouse model to determine whether increased SLN level affected muscle contractile properties, exercise capacity/fatigue, and metabolic rate in whole animals and isolated muscle. We found that SlnOE mice are more resistant to fatigue and can run significantly longer distances than wild-type (WT). Studies with isolated extensor digitorum longus (EDL) muscles showed that SlnOE EDL produced higher twitch force than WT. The force-frequency curves were not different between WT and SlnOE EDLs, but at lower frequencies the pyruvate-induced potentiation of force was significantly higher in SlnOE EDL. SLN overexpression did not alter the twitch and force-frequency curve in isolated soleus muscle. However, during a 10-min fatigue protocol, both EDL and soleus from SlnOE mice fatigued significantly less than WT muscles. Interestingly, SlnOE muscles showed higher carnitine palmitoyl transferase-1 protein expression, which could enhance fatty acid metabolism. In addition, lactate dehydrogenase expression was higher in SlnOE EDL, suggesting increased glycolytic capacity. We also found an increase in store-operated calcium entry (SOCE) in isolated flexor digitorum brevis fibers of SlnOE compared with WT mice. These data allow us to conclude that increased SLN expression improves skeletal muscle performance during prolonged muscle activity by increasing SOCE and muscle energetics. PMID:25701006

  12. Understanding Selective Downregulation of c-Myc Expression through Inhibition of General Transcription Regulators in Multiple Myeloma

    Science.gov (United States)

    2014-06-01

    3 weeks, observing no effect on endurance exercise capacity (Figure S3A), a metric of global cardiometabolic health. For in vivo studies, we first...0.0001 KEGG_PATHWAY mmu05322:Systemic lupus erythematosus 4 ɘ.0001 C D E F G IKK2 Tg GATA4 Tg A Day 0 1.5 JQ1 50 mg/kg/d IP vs. veh 28 TAC/sham 3 11 G

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

    NARCIS (Netherlands)

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

    1985-01-01

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

  14. Isolation and characterization of exosome from human embryonic stem cell-derived c-myc-immortalized mesenchymal stem cells

    NARCIS (Netherlands)

    Lai, Ruenn Chai; Yeo, Ronne Wee Yeh; Padmanabhan, Jayanthi; Choo, Andre; De Kleijn, Dominique P V; Lim, Sai Kiang

    2016-01-01

    Mesenchymal stem cells (MSC) are currently the cell type of choice in many cell therapy trials. The number of therapeutic applications for MSCs registered as product IND submissions with the FDA and initiation of registered clinical trials has increased substantially in recent years, in particular

  15. High-Content FRET-FLIM Screening in Inhibitors of Oncogenic Transcription by C-Myc in Breast Cancer

    Science.gov (United States)

    2009-06-01

    Benetatos CA, Chunduru SK, Condon SM, McKinlay M, Brink R, Leverkus M, Tergaonkar V, Schneider P, Callus BA, Koentgen F, Vaux DL, Silke J. IAP...and 4. B) Anchorage-independent growth of MCF10A cells is increased with ectopic expression of wild- type Myc, as measured by colony formation in

  16. Understanding Selective Downregulation of c-Myc Expression through Inhibition of General Transcription Regulators in Multiple Myeloma

    Science.gov (United States)

    2015-06-01

    system organ failure and death (Medzhitov et al., 2012). Chronic, low-grade inflammation is a pathogenic feature of autoimmune disorders as well as...bromodomain inhibition has been shown to abrogate global, maladaptive tran- scriptional programs during sepsis and heart failure, implicating BRD4 in stress...inflammatory disorders , including atherogenesis, in which activation of ECs is pathogenic (Gim- brone et al., 1990; Ley et al., 2007). Despite these

  17. Electrochemiluminescence detection of c-Myc mRNA in breast cancer cells on a wireless bipolar electrode.

    Science.gov (United States)

    Wu, Mei-Sheng; Qian, Guang-sheng; Xu, Jing-Juan; Chen, Hong-Yuan

    2013-01-01

    Electrochemiluminescence (ECL) on bipolar electrode (BPE) is a sensitive, portable, and low-cost approach which has been employed to detect DNA and proteins. Here, we develop an ultrasensitive method for intracellular mRNA assay based on mRNA-mediated reporter DNA liberation and Ru(bpy)3(2+)-conjugated silica nanoparticles (RuSi@Ru(bpy)3(2+)) tag-based signal amplification.

  18. Amino-terminal domains of c-myc and N-myc proteins mediate binding to the retinoblastoma gene product

    NARCIS (Netherlands)

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

    1991-01-01

    The proteins encoded by the myc gene family are involved is the control of cell proliferation and differentiation, and aberrant expression of myc proteins has been implicated in the genesis of a variety of neoplasms. In the carboxyl terminus, myc proteins have two domains that encode a basic

  19. Focal adhesion kinase is required for intestinal regeneration and tumorigenesis downstream of Wnt/c-Myc signaling

    NARCIS (Netherlands)

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

    2010-01-01

    The intestinal epithelium has a remarkable capacity to regenerate after injury and DNA damage. Here, we show that the integrin effector protein Focal Adhesion Kinase (FAK) is dispensable for normal intestinal homeostasis and DNA damage signaling, but is essential for intestinal regeneration

  20. Effects of c-myc oncogene modulation on drug resistance in human small cell lung carcinoma cell lines

    NARCIS (Netherlands)

    vanWaardenburg, RCAM; Meijer, C; Uges, DRA; deVries, EGE; Mulder, NH

    1996-01-01

    Small cell lung carcinoma (SCLC) is characterized by rapid development of resistance to drugs, such as cis-diamminedichloroplatinum(II) (cDDP) and anthracyclines. The molecular basis for resistance to cDDP and adriamycin (Adr) is poorly understood. One of the genetic alterations observed in SCLC,

  1. Over-expression of HER-2 is associated with the stage in ...

    African Journals Online (AJOL)

    Materials and methods: Archival samples from 39 patients (6 women, 33 males) with urinary bladder cancer were analyzed for HER-2 over-expression, using immunohistochemistry with the HercepTest. Results: HER-2 over-expression was observed in 23/39 tumors (59%) and was more frequent in high-grade than in ...

  2. ADAM12 overexpression does not improve outcome in mice with laminin alpha2-deficient muscular dystrophy

    DEFF Research Database (Denmark)

    Guo, Ling T; Shelton, G Diane; Wewer, Ulla M

    2005-01-01

    We have recently shown that overexpression of ADAM12 results in increased muscle regeneration and significantly reduced pathology in mdx, dystrophin deficient mice. In the present study, we tested the effect of overexpressing ADAM12 in dy(W) laminin-deficient mice. dy mice have a very severe clin...

  3. Correlation between human papillomavirus and p16 overexpression in oropharyngeal tumours

    DEFF Research Database (Denmark)

    Grønhøj Larsen, C; Gyldenløve, M; Jensen, D H

    2014-01-01

    A significant proportion of squamous cell carcinomas of the oropharynx (OP-SCC) are related to human papillomavirus (HPV) infection and p16 overexpression. This subgroup proves better prognosis and survival but no evidence exists on the correlation between HPV and p16 overexpression based...

  4. Optimizing Membrane Protein Overexpression in the Escherichia coli strain Lemo21(DE3)

    NARCIS (Netherlands)

    Schlegel, Susan; Lofblom, John; Lee, Chiara; Hjelm, Anna; Klepsch, Mirjam; Strous, Marc; Drew, David; Slotboom, Dirk Jan; de Gier, Jan-Willem

    2012-01-01

    Escherichia coli BL21(DE3) is widely used to overexpress proteins. In this overexpression host, the gene encoding the target protein is located on a plasmid and is under control of the T7 promoter, which is recognized exclusively by the T7 RNA polymerase (RNAP). The 17 RNAP gene is localized on the

  5. Overexpression of mineralocorticoid receptors does not affect memory and anxiety-like behavior in female mice

    Directory of Open Access Journals (Sweden)

    Sofia eKanatsou

    2015-07-01

    Full Text Available Mineralocorticoid receptors (MRs have been implicated in behavioral adaptation and learning and memory. Since – at least in humans - MR function seems to be sex-dependent, we examined the behavioral relevance of MR in female mice exhibiting transgenic MR overexpression in the forebrain. Transgenic MR overexpression did not affect contextual fear memory or cued fear learning and memory. Moreover, MR overexpressing and control mice discriminated equally well between fear responses in a combined cue and context fear conditioning paradigm. Also context-memory in an object recognition task was unaffected in MR overexpressing mice. We conclude that MR overexpression in female animals does not affect fear conditioned responses and object recognition memory.

  6. Increased isobutanol production in Saccharomyces cerevisiae by overexpression of genes in valine metabolism

    DEFF Research Database (Denmark)

    Chen, Xiao; Nielsen, Kristian Fog; Borodina, Irina

    2011-01-01

    BACKGROUND: Isobutanol can be a better biofuel than ethanol due to its higher energy density and lower hygroscopicity. Furthermore, the branched-chain structure of isobutanol gives a higher octane number than the isomeric n-butanol. Saccharomyces cerevisiae was chosen as the production host because...... overexpression of biosynthetic genes ILV2, ILV3, and ILV5 in valine metabolism in anaerobic fermentation of glucose in mineral medium in S. cerevisiae. Isobutanol yield was further improved by twofold by the additional overexpression of BAT2, encoding the cytoplasmic branched-chain amino-acid aminotransferase....... Overexpression of ILV6, encoding the regulatory subunit of Ilv2, in the ILV2 ILV3 ILV5 overexpression strain decreased isobutanol production yield by threefold. In aerobic cultivations in shake flasks in mineral medium, the isobutanol yield of the ILV2 ILV3 ILV5 overexpression strain and the reference strain...

  7. RCAN1 overexpression exacerbates calcium overloading-induced neuronal apoptosis.

    Directory of Open Access Journals (Sweden)

    Xiulian Sun

    Full Text Available Down Syndrome (DS patients develop characteristic Alzheimer's Disease (AD neuropathology after their middle age. Prominent neuronal loss has been observed in the cortical regions of AD brains. However, the underlying mechanism leading to this neuronal loss in both DS and AD remains to be elucidated. Calcium overloading and oxidative stress have been implicated in AD pathogenesis. Two major isoforms of regulator of calcineurin 1 (RCAN1, RCAN1.1 and RCAN1.4, are detected in human brains. In this report we defined the transcriptional regulation of RCAN1.1 and RCAN1.4 by two alternative promoters. Calcium overloading upregulated RCAN1.4 expression by activating RCAN1.4 promoter through calcineurin-NFAT signaling pathway, thus forming a negative feedback loop in isoform 4 regulation. Furthermore, RCAN1.4 overexpression exacerbated calcium overloading-induced neuronal apoptosis, which was mediated by caspase-3 apoptotic pathway. Our results suggest that downregulating RCAN1.4 expression in neurons could be beneficial to AD patients.

  8. RCAN1 overexpression exacerbates calcium overloading-induced neuronal apoptosis.

    Science.gov (United States)

    Sun, Xiulian; Wu, Yili; Herculano, Bruno; Song, Weihong

    2014-01-01

    Down Syndrome (DS) patients develop characteristic Alzheimer's Disease (AD) neuropathology after their middle age. Prominent neuronal loss has been observed in the cortical regions of AD brains. However, the underlying mechanism leading to this neuronal loss in both DS and AD remains to be elucidated. Calcium overloading and oxidative stress have been implicated in AD pathogenesis. Two major isoforms of regulator of calcineurin 1 (RCAN1), RCAN1.1 and RCAN1.4, are detected in human brains. In this report we defined the transcriptional regulation of RCAN1.1 and RCAN1.4 by two alternative promoters. Calcium overloading upregulated RCAN1.4 expression by activating RCAN1.4 promoter through calcineurin-NFAT signaling pathway, thus forming a negative feedback loop in isoform 4 regulation. Furthermore, RCAN1.4 overexpression exacerbated calcium overloading-induced neuronal apoptosis, which was mediated by caspase-3 apoptotic pathway. Our results suggest that downregulating RCAN1.4 expression in neurons could be beneficial to AD patients.

  9. GNB3 overexpression causes obesity and metabolic syndrome.

    Science.gov (United States)

    Ozdemir, Alev Cagla; Wynn, Grace M; Vester, Aimee; Weitzmann, M Neale; Neigh, Gretchen N; Srinivasan, Shanthi; Rudd, M Katharine

    2017-01-01

    The G-protein beta subunit 3 (GNB3) gene has been implicated in obesity risk; however, the molecular mechanism of GNB3-related disease is unknown. GNB3 duplication is responsible for a syndromic form of childhood obesity, and an activating DNA sequence variant (C825T) in GNB3 is also associated with obesity. To test the hypothesis that GNB3 overexpression causes obesity, we created bacterial artificial chromosome (BAC) transgenic mice that carry an extra copy of the human GNB3 risk allele. Here we show that GNB3-T/+ mice have increased adiposity, but not greater food intake or a defect in satiety. GNB3-T/+ mice have elevated fasting plasma glucose, insulin, and C-peptide, as well as glucose intolerance, indicating type 2 diabetes. Fasting plasma leptin, triglycerides, cholesterol and phospholipids are elevated, suggesting metabolic syndrome. Based on a battery of behavioral tests, GNB3-T/+ mice did not exhibit anxiety- or depressive-like phenotypes. GNB3-T/+ and wild-type animals have similar activity levels and heat production; however, GNB3-T/+ mice exhibit dysregulation of acute thermogenesis. Finally, Ucp1 expression is significantly lower in white adipose tissue (WAT) in GNB3-T/+ mice, suggestive of WAT remodeling that could lead to impaired cellular thermogenesis. Taken together, our study provides the first functional link between GNB3 and obesity, and presents insight into novel pathways that could be applied to combat obesity and type 2 diabetes.

  10. Overexpression of Eag1 potassium channels in clinical tumours

    Directory of Open Access Journals (Sweden)

    Schliephacke Tessa

    2006-10-01

    Full Text Available Abstract Background Certain types of potassium channels (known as Eag1, KCNH1, Kv10.1 are associated with the production of tumours in patients and in animals. We have now studied the expression pattern of the Eag1 channel in a large range of normal and tumour tissues from different collections utilising molecular biological and immunohistochemical techniques. Results The use of reverse transcription real-time PCR and specifically generated monoclonal anti-Eag1 antibodies showed that expression of the channel is normally limited to specific areas of the brain and to restricted cell populations throughout the body. Tumour samples, however, showed a significant overexpression of the channel with high frequency (up to 80% depending on the tissue source regardless of the detection method (staining with either one of the antibodies, or detection of Eag1 RNA. Conclusion Inhibition of Eag1 expression in tumour cell lines reduced cell proliferation. Eag1 may therefore represent a promising target for the tailored treatment of human tumours. Furthermore, as normal cells expressing Eag1 are either protected by the blood-brain barrier or represent the terminal stage of normal differentiation, Eag1 based therapies could produce only minor side effects.

  11. Reduced antimony accumulation in ARM58-overexpressing Leishmania infantum.

    Science.gov (United States)

    Schäfer, Carola; Tejera Nevado, Paloma; Zander, Dorothea; Clos, Joachim

    2014-01-01

    Antimony-based drugs are still the mainstay of chemotherapy against Leishmania infections in many countries where the parasites are endemic. The efficacy of antimonials has been compromised by increasing numbers of resistant infections, the basis of which is not fully understood and likely involves multiple factors. By using a functional cloning strategy, we recently identified a novel antimony resistance marker, ARM58, from the parasite Leish