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Sample records for exerts tumor suppressor

  1. MicroRNA-219-5p exerts tumor suppressor function by targeting ROBO1 in glioblastoma.

    Science.gov (United States)

    Jiang, Yongmei; Yin, Lin; Jing, Huirong; Zhang, Hui

    2015-11-01

    Previous studies have shown that miR-219-5p is dysregulated and exerts tumor-suppressive effects in cancer development and progression. However, the molecular function and mechanism of miR-219-5p in glioblastoma growth and invasion are still unclear. In the present study, we show that miR-219-5p was downregulated in a panel of glioma tissues with different grades and in all the human glioma cell lines examined. Ectopic expression of miR-219-5p inhibited proliferation and invasion and induced apoptosis in vitro, and xenograft formation in vivo. ROBO1 was found to be a direct target of miR-219-5p, and when overexpressed in miR-219-5p-expressing glioma cells, was able to restore proliferative and invasive ability. Finally, in vivo investigation confirmed that miR-219-5p was a tumor suppressor that regulated ROBO1 expression. Taken together, these studies demonstrate that miR-219-5p inhibited cancer cell growth and invasion by direct targeting ROBO1, implicating miR-219-5p as an attractive candidate for cancer therapy.

  2. Tumor suppressors: enhancers or suppressors of regeneration?

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    Pomerantz, Jason H.; Blau, Helen M.

    2013-01-01

    Tumor suppressors are so named because cancers occur in their absence, but these genes also have important functions in development, metabolism and tissue homeostasis. Here, we discuss known and potential functions of tumor suppressor genes during tissue regeneration, focusing on the evolutionarily conserved tumor suppressors pRb1, p53, Pten and Hippo. We propose that their activity is essential for tissue regeneration. This is in contrast to suggestions that tumor suppression is a trade-off for regenerative capacity. We also hypothesize that certain aspects of tumor suppressor pathways inhibit regenerative processes in mammals, and that transient targeted modification of these pathways could be fruitfully exploited to enhance processes that are important to regenerative medicine. PMID:23715544

  3. Tumor suppressor protein p53 exerts negative transcriptional regulation on human sodium iodide symporter gene expression in breast cancer.

    Science.gov (United States)

    Kelkar, Madhura G; Thakur, Bhushan; Derle, Abhishek; Chatterjee, Sushmita; Ray, Pritha; De, Abhijit

    2017-08-01

    Aberrant expression of human sodium iodide symporter (NIS) in breast cancer (BC) is well documented but the transcription factors (TF) regulating its aberrant expression is poorly known. We identify the presence of three p53 binding sites on the human NIS promoter sequence by conducting genome-wide TF analysis, and further investigate their regulatory role. The differences in transcription and translation were measured by real-time PCR, luciferase reporter assay, site-directed mutagenesis, in vivo optical imaging, and chromatin immunoprecipitation. The relation of NIS and p53 in clinical samples was judged by TCGA data analysis and immunohistochemistry. Overexpression of wild-type p53 as a transgene or pharmacological activation by doxorubicin drug treatment shows significant suppression of NIS transcription in multiple BC cell types which also results in lowered NIS protein content and cellular iodide intake. NIS repression by activated p53 is further confirmed by non-invasive bioluminescence imaging in live cell and orthotropic tumor model. Abrogation of p53-binding sites by directional mutagenesis confirms reversal of transcriptional activity in wild-type p53-positive BC cells. We also observe direct binding of p53 to these sites on the human NIS promoter. Importantly, TCGA data analysis of NIS and p53 co-expression registers an inverse relationship between the two candidates. Our data for the first time highlight the role of p53 as a negative regulator of functional NIS expression in BC, where the latter is a potential targeted radioiodine therapy candidate. Thus, the study provides an important insight into prospective clinical application of this approach that may significantly impact the patient with mutant versus wild-type p53 profile.

  4. Tumor suppressor molecules and methods of use

    Science.gov (United States)

    Welch, Peter J.; Barber, Jack R.

    2004-09-07

    The invention provides substantially pure tumor suppressor nucleic acid molecules and tumor suppressor polypeptides. The invention also provides hairpin ribozymes and antibodies selective for these tumor suppressor molecules. Also provided are methods of detecting a neoplastic cell in a sample using detectable agents specific for the tumor suppressor nucleic acids and polypeptides.

  5. Metastasis Suppressors and the Tumor Microenvironment

    Science.gov (United States)

    Cook, Leah M.; Hurst, Douglas R.; Welch, Danny R.

    2011-01-01

    The most lethal and debilitating attribute of cancer cells is their ability to metastasize. Throughout the process of metastasis, tumor cells interact with other tumor cells, host cells and a variety of molecules. Tumor cells are also faced with a number of insults, such as hemodynamic sheer pressure and immune selection. This brief review explores how metastasis suppressor proteins regulate interactions between tumor cells and the microenvironments in which tumor cells find themselves. PMID:21168504

  6. Retinoblastoma tumor suppressor gene: An overview

    Directory of Open Access Journals (Sweden)

    Sunila Thomas

    2012-01-01

    Full Text Available A genetic basis for the development of cancer has been hypothesized for nearly a century and has been supported by familial, epidemiological and cytogenetic studies. Current view is that carcinogenesis is a multistep process involving activation of oncogenes or inactivation of tumor suppressor genes. Tumor suppressor gene is a gene whose protein product can inhibit the transformation of a normal cell to a tumor cell and therefore, whose loss of function can contribute to the malignant transformation of cell. The retinoblastoma gene (Rb is the first tumor suppressor gene identified and plays a key role in the regulation of cell cycle. A diverse body of evidence now indicates that pRb stands in the midst of a regulatory pathway and suffers disruption during the pathogenesis of majority of human tumors, including oral cancers- However, recent studies point to a more general function of pRb. In addition to tumor suppression, Rb has a role in cellular differentiation and apoptosis. This review provides an insight into the complex functions of pRb with particular reference to its role in tumor suppression.

  7. Tumor suppressor identified as inhibitor of inflammation

    Science.gov (United States)

    Scientists at NCI have found that a protein, FBXW7, which acts as a tumor suppressor, is also important for the reduction in strength of inflammatory pathways. It has long been recognized that a complex interaction exists between cancer causing mechanisms

  8. Targeting tumor suppressor genes for cancer therapy.

    Science.gov (United States)

    Liu, Yunhua; Hu, Xiaoxiao; Han, Cecil; Wang, Liana; Zhang, Xinna; He, Xiaoming; Lu, Xiongbin

    2015-12-01

    Cancer drugs are broadly classified into two categories: cytotoxic chemotherapies and targeted therapies that specifically modulate the activity of one or more proteins involved in cancer. Major advances have been achieved in targeted cancer therapies in the past few decades, which is ascribed to the increasing understanding of molecular mechanisms for cancer initiation and progression. Consequently, monoclonal antibodies and small molecules have been developed to interfere with a specific molecular oncogenic target. Targeting gain-of-function mutations, in general, has been productive. However, it has been a major challenge to use standard pharmacologic approaches to target loss-of-function mutations of tumor suppressor genes. Novel approaches, including synthetic lethality and collateral vulnerability screens, are now being developed to target gene defects in p53, PTEN, and BRCA1/2. Here, we review and summarize the recent findings in cancer genomics, drug development, and molecular cancer biology, which show promise in targeting tumor suppressors in cancer therapeutics. © 2015 WILEY Periodicals, Inc.

  9. Microbial Regulation of p53 Tumor Suppressor.

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    Alexander I Zaika

    2015-09-01

    Full Text Available p53 tumor suppressor has been identified as a protein interacting with the large T antigen produced by simian vacuolating virus 40 (SV40. Subsequent research on p53 inhibition by SV40 and other tumor viruses has not only helped to gain a better understanding of viral biology, but also shaped our knowledge of human tumorigenesis. Recent studies have found, however, that inhibition of p53 is not strictly in the realm of viruses. Some bacterial pathogens also actively inhibit p53 protein and induce its degradation, resulting in alteration of cellular stress responses. This phenomenon was initially characterized in gastric epithelial cells infected with Helicobacter pylori, a bacterial pathogen that commonly infects the human stomach and is strongly linked to gastric cancer. Besides H. pylori, a number of other bacterial species were recently discovered to inhibit p53. These findings provide novel insights into host-bacteria interactions and tumorigenesis associated with bacterial infections.

  10. The tumor suppressor CDKN3 controls mitosis.

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    Nalepa, Grzegorz; Barnholtz-Sloan, Jill; Enzor, Rikki; Dey, Dilip; He, Ying; Gehlhausen, Jeff R; Lehmann, Amalia S; Park, Su-Jung; Yang, Yanzhu; Yang, Xianlin; Chen, Shi; Guan, Xiaowei; Chen, Yanwen; Renbarger, Jamie; Yang, Feng-Chun; Parada, Luis F; Clapp, Wade

    2013-06-24

    Mitosis is controlled by a network of kinases and phosphatases. We screened a library of small interfering RNAs against a genome-wide set of phosphatases to comprehensively evaluate the role of human phosphatases in mitosis. We found four candidate spindle checkpoint phosphatases, including the tumor suppressor CDKN3. We show that CDKN3 is essential for normal mitosis and G1/S transition. We demonstrate that subcellular localization of CDKN3 changes throughout the cell cycle. We show that CDKN3 dephosphorylates threonine-161 of CDC2 during mitotic exit and we visualize CDC2(pThr-161) at kinetochores and centrosomes in early mitosis. We performed a phosphokinome-wide mass spectrometry screen to find effectors of the CDKN3-CDC2 signaling axis. We found that one of the identified downstream phosphotargets, CKβ phosphorylated at serine 209, localizes to mitotic centrosomes and controls the spindle checkpoint. Finally, we show that CDKN3 protein is down-regulated in brain tumors. Our findings indicate that CDKN3 controls mitosis through the CDC2 signaling axis. These results have implications for targeted anticancer therapeutics.

  11. Studies of Tumor Suppressor Genes via Chromosome Engineering

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    Hiroyuki Kugoh

    2015-12-01

    Full Text Available The development and progression of malignant tumors likely result from consecutive accumulation of genetic alterations, including dysfunctional tumor suppressor genes. However, the signaling mechanisms that underlie the development of tumors have not yet been completely elucidated. Discovery of novel tumor-related genes plays a crucial role in our understanding of the development and progression of malignant tumors. Chromosome engineering technology based on microcell-mediated chromosome transfer (MMCT is an effective approach for identification of tumor suppressor genes. The studies have revealed at least five tumor suppression effects. The discovery of novel tumor suppressor genes provide greater understanding of the complex signaling pathways that underlie the development and progression of malignant tumors. These advances are being exploited to develop targeted drugs and new biological therapies for cancer.

  12. The ING tumor suppressor genes: status in human tumors.

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    Guérillon, Claire; Bigot, Nicolas; Pedeux, Rémy

    2014-04-01

    ING genes (ING1-5) were identified has tumor suppressor genes. ING proteins are characterized as Type II TSGs since they are involved in the control of cell proliferation, apoptosis and senescence. They may also function as Type I TSGs since they are also involved in DNA replication and repair. Most studies have reported that they are frequently lost in human tumors and epigenetic mechanisms or misregulation of their transcription may be involved. Recently, studies have described that this loss may be caused by microRNA inhibition. Here, we summarize the current knowledge on ING functions, their involvement in tumor suppression and, in order to give a full assessment of the current knowledge, we review all the studies that have examined ING status in human cancers. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  13. Genetic alterations of tumor suppressor gene in sporadic colorectal cancers

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    Hadžiavdić Vesna

    2012-01-01

    Full Text Available Colorectal cancer with its frequency, high mortality rate as well as many etiological unknowns is a challenge to contemporary science. Finally, genetic information could be used in near future for prevention of colorectal cancer, its early diagnosis and selection for the most suitable hospital treatment. In this study, we analysed genetic alterations of tumor suppressor genes and the possibility of quick and efficient screening method for identification of colorectal cancer. The study consisted of 54 samples of tumor and surrounding healthy tissue of patients with colorectal cancer, which is clasificated according to Bethesda and Amsterdams criterias. The investigation showed that genetic alterations of tumor suppressor gene NM 23 were present in 19/35 (54,29% samples, and tumor suppressor gene p53 in 18/35 (51,43%, APC in 18/35 (51,43%, DCC2 tumor suppressor gene in 12/35 (34,29%, tumor suppressor gene RB1 in 8 /35 (22, 86% and DCC 1 in 10/35 ( 28,57% tumor tissue.

  14. RET is a potential tumor suppressor gene in colorectal cancer

    Science.gov (United States)

    Luo, Yanxin; Tsuchiya, Karen D.; Park, Dong Il; Fausel, Rebecca; Kanngurn, Samornmas; Welcsh, Piri; Dzieciatkowski, Slavomir; Wang, Jianping; Grady, William M.

    2012-01-01

    Cancer arises as the consequence of mutations and epigenetic alterations that activate oncogenes and inactivate tumor suppressor genes. Through a genome-wide screen for methylated genes in colon neoplasms, we identified aberrantly methylated RET in colorectal cancer. RET, a transmembrane receptor tyrosine kinase and a receptor for the GDNF-family ligands, was one of the first oncogenes to be identified and has been shown to be an oncogene in thyroid cancer and pheochromocytoma. However, unexpectedly, we found RET is methylated in 27% of colon adenomas and in 63% of colorectal cancers, and now provide evidence that RET has tumor suppressor activity in colon cancer. The aberrant methylation of RET correlates with decreased RET expression, whereas the restoration of RET in colorectal cancer cell lines results in apoptosis. Furthermore, in support of a tumor suppressor function of RET, mutant RET has also been found in primary colorectal cancer. We now show that these mutations inactivate RET, which is consistent with RET being a tumor suppressor gene in the colon. These findings suggest that the aberrant methylation of RET and the mutational inactivation of RET promote colorectal cancer formation and that RET can serve as a tumor suppressor gene in the colon. Moreover, the increased frequency of methylated RET in colon cancers compared to adenomas suggests RET inactivation is involved in the progression of colon adenomas to cancer. PMID:22751117

  15. A functional dissection of PTEN N-terminus : Implications in PTEN subcellular targeting and tumor suppressor activity

    NARCIS (Netherlands)

    Gil, Anabel; Rodríguez-Escudero, Isabel; Stumpf, Miriam; Molina, María; Cid, Víctor J.; Pulido, Rafael

    2015-01-01

    Spatial regulation of the tumor suppressor PTEN is exerted through alternative plasma membrane, cytoplasmic, and nuclear subcellular locations. The N-terminal region of PTEN is important for the control of PTEN subcellular localization and function. It contains both an active nuclear localization

  16. "Ring-fencing" BRCA1 tumor suppressor activity.

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    Patel, Ketan J; Crossan, Gerry P; Hodskinson, Michael R G

    2011-12-13

    BRCA1 is a crucial human breast and ovarian cancer tumor suppressor gene. The article by Drost et al. in this issue of Cancer Cell together with a recent paper in Science now provide a clearer picture of how this large and complex protein suppresses tumorigenesis. Copyright © 2011 Elsevier Inc. All rights reserved.

  17. Tumor Suppressor Genes: A Key to the Cancer Puzzle?

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    Oppenheimer, Steven B.

    1991-01-01

    Author describes developments in understanding of tumor suppressor genes or antioncogenes that he feels is most important breakthrough in solving cancer problem. Describes 1969 starting work of Harris with mouse fibroblast genes and later work of Knudson with retinoblastoma cells. Provides evidence that deletion of chromosome that results in the…

  18. Mechanism for Mutational Inactivation of the Tumor Suppressor Smad2

    OpenAIRE

    Prunier, Celine; Ferrand, Nathalie; Frottier, Bertrand; Pessah, Marcia; Atfi, Azeddine

    2001-01-01

    Transforming growth factor β (TGF-β) is a potent natural antiproliferative agent that plays an important role in suppressing tumorigenicity. In numerous tumors, loss of TGF-β responsiveness is associated with inactivating mutations that can occur in components of this signaling pathway, such as the tumor suppressor Smad2. Although a general framework for how Smads transduce TGF-β signals has been proposed, the physiological relevance of alterations of Smad2 functions in promoting tumorigenesi...

  19. AZU-1: A Candidate Breast Tumor Suppressor and Biomarker for Tumor Progression

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Huei-Mei; Schmeichel, Karen L; Mian, I. Saira; Lelie`vre, Sophie; Petersen, Ole W; Bissell, Mina J

    2000-02-04

    To identify genes misregulated in the final stages of breast carcinogenesis, we performed differential display to compare the gene expression patterns of the human tumorigenic mammary epithelial cells, HMT-3522-T4-2, with those of their immediate premalignant progenitors, HMT-3522-S2. We identified a novel gene, called anti-zuai-1 (AZU-1), that was abundantly expressed in non- and premalignant cells and tissues but was appreciably reduced in breast tumor cell types and in primary tumors. The AZU-1 gene encodes an acidic 571-amino-acid protein containing at least two structurally distinct domains with potential protein-binding functions: an N-terminal serine and proline-rich domain with a predicted immunoglobulin-like fold and a C-terminal coiled-coil domain. In HMT-3522 cells, the bulk of AZU-1 protein resided in a detergent-extractable cytoplasmic pool and was present at much lower levels in tumorigenic T4-2 cells than in their nonmalignant counterparts. Reversion of the tumorigenic phenotype of T4-2 cells, by means described previously, was accompanied by the up-regulation of AZU-1. In addition, reexpression of AZU-1 in T4-2 cells, using viral vectors, was sufficient to reduce their malignant phenotype substantially, both in culture and in vivo. These results indicate that AZU-1 is a candidate breast tumor suppressor that may exert its effects by promoting correct tissue morphogenesis.

  20. The ING tumor suppressors in cellular senescence and chromatin

    Directory of Open Access Journals (Sweden)

    Ludwig Susann

    2011-07-01

    Full Text Available Abstract The Inhibitor of Growth (ING proteins represent a type II tumor suppressor family comprising five conserved genes, ING1 to ING5. While ING1, ING2 and ING3 proteins are stable components of the mSIN3a-HDAC complexes, the association of ING1, ING4 and ING5 with HAT protein complexes was also reported. Among these the ING1 and ING2 have been analyzed more deeply. Similar to other tumor suppressor factors the ING proteins are also involved in many cellular pathways linked to cancer and cell proliferation such as cell cycle regulation, cellular senescence, DNA repair, apoptosis, inhibition of angiogenesis and modulation of chromatin. A common structural feature of ING factors is the conserved plant homeodomain (PHD, which can bind directly to the histone mark trimethylated lysine of histone H3 (H3K4me3. PHD mutants lose the ability to undergo cellular senescence linking chromatin mark recognition with cellular senescence. ING1 and ING2 are localized in the cell nucleus and associated with chromatin modifying enzymes, linking tumor suppression directly to chromatin regulation. In line with this, the expression of ING1 in tumors is aberrant or identified point mutations are mostly localized in the PHD finger and affect histone binding. Interestingly, ING1 protein levels increase in replicative senescent cells, latter representing an efficient pathway to inhibit cancer proliferation. In association with this, suppression of p33ING1 expression prolongs replicative life span and is also sufficient to bypass oncogene-induced senescence. Recent analyses of ING1- and ING2-deficient mice confirm a tumor suppressive role of ING1 and ING2 and also indicate an essential role of ING2 in meiosis. Here we summarize the activity of ING1 and ING2 as tumor suppressors, chromatin factors and in development.

  1. ETV1 positively regulates transcription of tumor suppressor ARF

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    Zynda, Evan; Jackson, Mark W; Bhattacharya, Partho; Kandel, Eugene S

    2013-01-01

    ETV1 (ETS variant 1) is a transcription factor from the ETS family and an oncogene in several types of human malignancies. Paradoxically, a predicted inactivating mutation in ETV1 was previously found in a clone of HT1080 cells with reduced activity of p53. We report that elevated expression of ETV1 makes p53-null tumor cells hypersensitive to restoration of said tumor suppressor. Furthermore, elevated levels of either wild-type ETV1 or its truncated derivative, dETV1, which mimics the product of an oncogenic rearrangement in certain tumors, results in increased expression of mRNA for p14ARF, a known activator of p53. Accordingly, expression of a luciferase reporter, which is driven by a putative ARF promoter, was elevated by concomitant expression of either ETV1 or dETV1. Our observations point to yet another example of a tumor suppressor gene being activated by a potentially oncogenic signal. A better understanding of the mechanisms that allow a cell to bypass such safeguards is needed in order to predict and prevent the development of an oncogene-tolerant state during cancer evolution. PMID:24157551

  2. The WTX Tumor Suppressor Regulates Mesenchymal Progenitor Cell Fate Specification

    Science.gov (United States)

    Lotinun, Sutada; Akhavanfard, Sara; Coffman, Erik J.; Cook, Edward B.; Stoykova, Svetlana; Mukherjee, Siddhartha; Schoonmaker, Jesse A.; Burger, Alexa; Kim, Woo Jae; Kronenberg, Henry M.; Baron, Roland; Haber, Daniel A.; Bardeesy, Nabeel

    2014-01-01

    SUMMARY WTX is an X-linked tumor suppressor targeted by somatic mutations in Wilms tumor, a pediatric kidney cancer, and by germline inactivation in osteopathia striata with cranial sclerosis, a bone overgrowth syndrome. Here, we show that Wtx deletion in mice causes neonatal lethality, somatic overgrowth, and malformation of multiple mesenchyme-derived tissues, including bone, fat, kidney, heart, and spleen. Inactivation of Wtx at different developmental stages and in primary mesenchymal progenitor cells (MPCs) reveals that bone mass increase and adipose tissue deficiency are due to altered lineage fate decisions coupled with delayed terminal differentiation. Specification defects in MPCs result from aberrant β-catenin activation, whereas alternative pathways contribute to the subsequently delayed differentiation of lineage-restricted cells. Thus, Wtx is a regulator of MPC commitment and differentiation with stage-specific functions in inhibiting canonical Wnt signaling. Furthermore, the constellation of anomalies in Wtx null mice suggests that this tumor suppressor broadly regulates MPCs in multiple tissues. PMID:21571217

  3. [HINT1--a novel tumor suppressor protein of the HIT superfamily].

    Science.gov (United States)

    Ozga, Magdalena

    2010-01-01

    The histidine triad nucleotide binding protein1 (Hint1) belongs to the first branch of the HIT superfamily. Hint1 catalyses the process of hydrolysis of the P-N bond in AMP-lysine, AMP-alanine, AMP-NH2. The physiological role of this enzyme is still unclear. There is accumulating evidence that HINT1 is a novel tumor suppressor protein, albeit the mechanism of action of HINT1 in respect to tumor suppression is not fully understood. Recent findings have shown that Hint1 inhibits the activity of the transcription factors AP1, MITF and USF2, as well as influences the transcription process of some genes of Wnt/beta-catenin pathway. Thereby, it seems that Hint1 exerts its major cellular function as gene transcription regulator, and thus, this function provides its potential role as a tumor suppressor protein. The clinical relevance of impairments in the Hint1 expression with the respect to specific human cancers is still a matter of extensive studies.

  4. The von Hippel Lindau tumor suppressor limits longevity.

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    Müller, Roman-Ulrich; Fabretti, Francesca; Zank, Sibylle; Burst, Volker; Benzing, Thomas; Schermer, Bernhard

    2009-12-01

    Many genes are responsible for the modulation of lifespan in model organisms. In addition to regulating adaptive biologic responses that control stress signaling and longevity, some of these genes participate in tumor formation. The mechanisms that determine longevity and link regulation of lifespan with tumorigenesis are poorly understood. Here, we show that the tumor suppressor von Hippel-Lindau (VHL), which has widely known roles in renal carcinogenesis and the formation of kidney cysts, controls longevity in Caenorhabditis elegans. Loss of vhl-1 significantly increased lifespan and resulted in accelerated basal signaling of the p38 mitogen-activated protein kinase PMK-3. Furthermore, the VHL-1 effect on the regulation of lifespan was independent of the insulin/IGF-1-like signaling pathway, suggesting a mechanism for stress resistance that controls both lifespan and tumorigenesis. These findings define VHL-1 as a player in longevity signaling and connect aging, regulation of lifespan, and stress responses with formation of renal cell carcinomas.

  5. Axl acts as a tumor suppressor by regulating LIGHT expression in T lymphoma.

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    Lee, Eun-Hee; Kim, Eun-Mi; Ji, Kon-Young; Park, A-Reum; Choi, Ha-Rim; Lee, Hwa-Youn; Kim, Su-Man; Chung, Byung Yeoup; Park, Chul-Hong; Choi, Hyo Jin; Ko, Young-Hyeh; Bai, Hyoung-Woo; Kang, Hyung-Sik

    2017-03-28

    Axl is an oncogenic receptor tyrosine kinase that plays a role in many cancers. LIGHT (Lymphotoxin-related inducible ligand that competes for glycoprotein D binding to herpesvirus entry mediator on T cells) is a ligand that induces robust anti-tumor immunity by enhancing the recruitment and activation of effector immune cells at tumor sites. We observed that mouse EL4 and human Jurkat T lymphoma cells that stably overexpressed Axl also showed high expression of LIGHT. When Jurkat-Axl cells were treated with Gas6, a ligand for Axl, LIGHT expression was upregulated through activation of the PI3K/AKT signaling pathway and transcriptional induction by Sp1. The lytic activity of cytotoxic T lymphocytes and natural killer cells was enhanced by EL4-Axl cells. In addition, tumor volume and growth were markedly reduced due to enhanced apoptotic cell death in EL4-Axl tumor-bearing mice as compared to control mice. We also observed upregulated expression of CCL5 and its receptor, CCR5, and enhanced intratumoral infiltration of cytotoxic T lymphocytes and natural killer cells in EL4-Axl-bearing mice as compared to mock controls. These data strongly suggested that Axl exerts novel tumor suppressor effects by inducing upregulation of LIGHT in the tumor microenvironment of T lymphoma.

  6. Mechanism for Mutational Inactivation of the Tumor Suppressor Smad2

    Science.gov (United States)

    Prunier, Celine; Ferrand, Nathalie; Frottier, Bertrand; Pessah, Marcia; Atfi, Azeddine

    2001-01-01

    Transforming growth factor β (TGF-β) is a potent natural antiproliferative agent that plays an important role in suppressing tumorigenicity. In numerous tumors, loss of TGF-β responsiveness is associated with inactivating mutations that can occur in components of this signaling pathway, such as the tumor suppressor Smad2. Although a general framework for how Smads transduce TGF-β signals has been proposed, the physiological relevance of alterations of Smad2 functions in promoting tumorigenesis is still unknown. Here, we show that expression of Smad2.P445H, a tumor-derived mutation of Smad2 found in human cancer, suppresses the ability of the Smads to mediate TGF-β-induced growth arrest and transcriptional responses. Smad2.P445H is phosphorylated by the activated TGF-β receptor at the carboxy-terminal serine residues and associates with Smad3 and Smad4 but is unable to dissociate from the receptor. Upon ligand-induced phosphorylation, Smad2.P445H interacts stably with wild-type Smad2, thereby blocking TGF-β-induced nuclear accumulation of wild-type Smad2 and Smad2-dependent transcription. The ability of the Smad2.P445H to block the nuclear accumulation of wild-type Smad2 protein reveals a new mechanism for loss of sensitivity to the growth-inhibitory functions of TGF-β in tumor development. PMID:11313456

  7. Merlin sumoylation is required for its tumor suppressor activity.

    Science.gov (United States)

    Qi, Q; Liu, X; Brat, D J; Ye, K

    2014-10-09

    Merlin, encoded by the Neurofibromatosis 2 (NF2) gene, is a multifunctional tumor suppressor that integrates and regulates extracellular cues and intracellular signaling pathways, both at the plasma membrane and in the nucleus, to control cell proliferation, migration and invasion. Molecular mechanisms regulating merlin's tumor-suppressive activity have not been clearly defined. Here we report that merlin can be sumoylated on Lysine residue (K76) in vitro and in vivo. Sumoylation mediates merlin's intramolecular and intermolecular binding activities and regulates its cytoplasm/nucleus trafficking. Interestingly, sumoylation of merlin is regulated by its phosphorylation via Akt and PAK2 kinases. Mutation of K76 into arginine (R) abolishes its sumoylation, disrupts merlin cortical cytoskeleton residency and attenuates its stability. Using a K76R mutant merlin in a subcutaneous U87MG xenograft model, we demonstrate that merlin sumoylation is required for tumor-suppressive activity. Taken together, our findings indicate that merlin is sumoylated and that this post-translational modification is essential for tumor suppression.

  8. TANGO is a tumor suppressor of malignant melanoma.

    Science.gov (United States)

    Arndt, Stephanie; Bosserhoff, Anja K

    2006-12-15

    The TANGO gene was originally identified as a new family member of the melanoma inhibitory activity gene family. The gene codes for a 14 kDa protein of so far unknown function. In our study we revealed that TANGO was downregulated or lost in 9 melanoma cell lines when compared to normal melanocytes and in most of the 8 tumor samples analyzed. The losses were associated with advanced stage of the disease. These results were confirmed in situ by immunohistochemistry on 10 paraffin-embedded sections of human malignant melanoma primary tumors and melanoma skin metastases. A small reduction of TANGO was also seen in different benign and atypical nevi when compared to normal skin. For functional analysis of TANGO we evaluated TANGO re-expressing melanoma cell clones and antisense TANGO cell clones with a complete loss of TANGO. Functional assays with TANGO transfected or treated cell lines revealed that TANGO expression reduces motility, whereas reduction of TANGO enhances migration. Our studies, therefore, indicate that reduction of TANGO expression contributes to tumor progression. These results taken together provide the first indications for a tumor suppressor role of TANGO gene in human malignant melanoma. Copyright 2006 Wiley-Liss, Inc.

  9. HET is a Novel Tumor Suppressor Gene in Human Breast Cancer

    National Research Council Canada - National Science Library

    Oesterreich, Steffi

    1999-01-01

    .... In the first specific aim we will directly answer whether HET is the tumor suppressor gene by performing additional LOB analysis and mutational analysis of BET in breast cancer cell lines as well as in tumors...

  10. Metastasis Suppressors Regulate the Tumor Microenvironment by Blocking Recruitment of Prometastatic Tumor-Associated Macrophages.

    Science.gov (United States)

    Frankenberger, Casey; Rabe, Daniel; Bainer, Russell; Sankarasharma, Devipriya; Chada, Kiran; Krausz, Thomas; Gilad, Yoav; Becker, Lev; Rosner, Marsha Rich

    2015-10-01

    Triple-negative breast cancer (TNBC) patients have the highest risk of recurrence and metastasis. Because they cannot be treated with targeted therapies, and many do not respond to chemotherapy, they represent a clinically underserved group. TNBC is characterized by reduced expression of metastasis suppressors such as Raf kinase inhibitory protein (RKIP), which inhibits tumor invasiveness. Mechanisms by which metastasis suppressors alter tumor cells are well characterized; however, their ability to regulate the tumor microenvironment and the importance of such regulation to metastasis suppression are incompletely understood. Here, we use species-specific RNA sequencing to show that RKIP expression in tumors markedly reduces the number and metastatic potential of infiltrating tumor-associated macrophages (TAM). TAMs isolated from nonmetastatic RKIP(+) tumors, relative to metastatic RKIP(-) tumors, exhibit a reduced ability to drive tumor cell invasion and decreased secretion of prometastatic factors, including PRGN, and shed TNFR2. RKIP regulates TAM recruitment by blocking HMGA2, resulting in reduced expression of numerous macrophage chemotactic factors, including CCL5. CCL5 overexpression in RKIP(+) tumors restores recruitment of prometastatic TAMs and intravasation, whereas treatment with the CCL5 receptor antagonist Maraviroc reduces TAM infiltration. These results highlight the importance of RKIP as a regulator of TAM recruitment through chemokines such as CCL5. The clinical significance of these interactions is underscored by our demonstration that a signature comprised of RKIP signaling and prometastatic TAM factors strikingly separates TNBC patients based on survival outcome. Collectively, our findings identify TAMs as a previously unsuspected mechanism by which the metastasis-suppressor RKIP regulates tumor invasiveness, and further suggest that TNBC patients with decreased RKIP activity and increased TAM infiltration may respond to macrophage

  11. Tumor Suppressors in Zebrafish : From TP53 to PTEN and Beyond

    NARCIS (Netherlands)

    den Hertog, Jeroen

    2016-01-01

    Zebrafish are increasingly being used to study cancer. Almost all tumor types have been found in zebrafish. However, tumor incidence is relatively low and tumors develop late in life. Functional inactivation of tumor suppressors is a crucial step in cancer progression and more and more tumor

  12. Tumor suppressors in Zebrafish : From TP53 to PTEN and beyond

    NARCIS (Netherlands)

    den Hertog, Jeroen

    2016-01-01

    Zebrafish are increasingly being used to study cancer. Almost all tumor types have been found in zebrafish. However, tumor incidence is relatively low and tumors develop late in life. Functional inactivation of tumor suppressors is a crucial step in cancer progression and more and more tumor

  13. Molecular insights into NF2/Merlin tumor suppressor function.

    Science.gov (United States)

    Cooper, Jonathan; Giancotti, Filippo G

    2014-08-19

    The FERM domain protein Merlin, encoded by the NF2 tumor suppressor gene, regulates cell proliferation in response to adhesive signaling. The growth inhibitory function of Merlin is induced by intercellular adhesion and inactivated by joint integrin/receptor tyrosine kinase signaling. Merlin contributes to the formation of cell junctions in polarized tissues, activates anti-mitogenic signaling at tight-junctions, and inhibits oncogenic gene expression. Thus, inactivation of Merlin causes uncontrolled mitogenic signaling and tumorigenesis. Merlin's predominant tumor suppressive functions are attributable to its control of oncogenic gene expression through regulation of Hippo signaling. Notably, Merlin translocates to the nucleus where it directly inhibits the CRL4(DCAF1) E3 ubiquitin ligase, thereby suppressing inhibition of the Lats kinases. A dichotomy in NF2 function has emerged whereby Merlin acts at the cell cortex to organize cell junctions and propagate anti-mitogenic signaling, whereas it inhibits oncogenic gene expression through the inhibition of CRL4(DCAF1) and activation of Hippo signaling. The biochemical events underlying Merlin's normal function and tumor suppressive activity will be discussed in this Review, with emphasis on recent discoveries that have greatly influenced our understanding of Merlin biology. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  14. Enhancer-Mediated Oncogenic Function of the Menin Tumor Suppressor in Breast Cancer

    Directory of Open Access Journals (Sweden)

    Koen M.A. Dreijerink

    2017-03-01

    Full Text Available While the multiple endocrine neoplasia type 1 (MEN1 gene functions as a tumor suppressor in a variety of cancer types, we explored its oncogenic role in breast tumorigenesis. The MEN1 gene product menin is involved in H3K4 trimethylation and co-activates transcription. We integrated ChIP-seq and RNA-seq data to identify menin target genes. Our analysis revealed that menin-dependent target gene promoters display looping to distal enhancers that are bound by menin, FOXA1 and GATA3. In this fashion, MEN1 co-regulates a proliferative breast cancer-specific gene expression program in ER+ cells. In primary mammary cells, MEN1 exerts an anti-proliferative function by regulating a distinct expression signature. Our findings clarify the cell-type-specific functions of MEN1 and inform the development of menin-directed treatments for breast cancer.

  15. Epigenetic identification of ZNF545 as a functional tumor suppressor in multiple myeloma via activation of p53 signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Yu [Chongqing Key Laboratory of Molecular Oncology and Epigenetics, The First Affiliated Hospital of Chongqing Medical University, Chongqing (China); Zhan, Qian [The Center for Clinical Molecular Medical Detection, The First Affiliated Hospital of Chongqing Medical University, Chongqing (China); Xu, Hongying [Chongqing Key Laboratory of Molecular Oncology and Epigenetics, The First Affiliated Hospital of Chongqing Medical University, Chongqing (China); Li, Lili; Li, Chen [Cancer Epigenetics Laboratory, Department of Clinical Oncology, Sir YK Pao Center for Cancer and Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong and CUHK Shenzhen Research Institute (Hong Kong); Xiao, Qian; Xiang, Shili; Hui, Tianli [Chongqing Key Laboratory of Molecular Oncology and Epigenetics, The First Affiliated Hospital of Chongqing Medical University, Chongqing (China); Xiang, Tingxiu, E-mail: larissaxiang@163.com [Chongqing Key Laboratory of Molecular Oncology and Epigenetics, The First Affiliated Hospital of Chongqing Medical University, Chongqing (China); Ren, Guosheng, E-mail: rengs726@126.com [Chongqing Key Laboratory of Molecular Oncology and Epigenetics, The First Affiliated Hospital of Chongqing Medical University, Chongqing (China)

    2016-06-10

    The KRAB–zinc-finger protein ZNF545 was recently identified as a potential suppressor gene in several tumors. However, the regulatory mechanisms of ZNF545 in tumorigenesis remain unclear. In this study, we investigated the expression and roles of ZNF545 in multiple myeloma (MM). ZNF545 was frequently downregulated in MM tissues compared with non-tumor bone marrow tissues. ZNF545 expression was silenced by promoter methylation in MM cell lines, and could be restored by demethylation treatment. ZNF545 methylation was detected in 28.3% of MM tissues, compared with 4.3% of normal bone marrow tissues. ZNF545 transcriptionally activated the p53 signaling pathway but had no effect on Akt in MM, whereas ectopic expression of ZNF545 in silenced cells suppressed their proliferation and induced apoptosis. We therefore identified ZNF545 as a novel tumor suppressor inhibiting tumor growth through activation of the p53 pathway in MM. Moreover, tumor-specific methylation of ZNF545 may represent an epigenetic biomarker for MM diagnosis, and a potential target for specific therapy. -- Highlights: •Downregulated ZNF545 in MM tissues and cell lines and ectopic expression of ZNF545 suppresses tumor growth. •Tumor-specific methylation of ZNF545 represents an epigenetic biomarker for MM diagnosis, and a potential target for specific therapy. •ZNF545 exerts its tumor suppressive effects via transcriptional activating p53 pathway.

  16. Nit1 and Fhit tumor suppressor activities are additive.

    Science.gov (United States)

    Sun, Jin; Okumura, Hiroshi; Yearsley, Martha; Frankel, Wendy; Fong, Louise Y; Druck, Teresa; Huebner, Kay

    2009-08-15

    The fragile histidine triad gene (human FHIT, mouse Fhit) has been shown to act as a tumor suppressor gene. Nit1 and Fhit form a fusion protein, encoded by the NitFhit gene in flies and worms, suggesting that mammalian Nit1 and Fhit proteins, which are encoded by genes on different chromosomes in mammals, may function in the same signal pathway(s). A previous study showed that Nit1 deficiency in knockout mice confers a cancer prone phenotype, as does Fhit deficiency. We have now assessed the tumor susceptibility of Fhit(-/-)Nit1(-/-) mice and observed that double knockout mice develop more spontaneous and carcinogen-induced tumors than Fhit(-/-) mice, suggesting that the extent of tumor susceptibility due to Nit1 and Fhit deficiency is additive, and that Nit1 and Fhit affect distinct signal pathways in mammals. Nit1, like Fhit, is present in cytoplasm and mitochondria but not nuclei. Because Fhit deficiency affects responses to replicative and oxidative stress, we sought evidence for Nit1 function in response to such stresses in tissues and cultured cells: when treated with hydroxyurea, the normal kidney-derived double-deficient cells appear not to activate the pChk2 pathway and when treated with H(2)O(2), show little evidence of DNA damage, compared with wild type and Fhit(-/-) cells. The relevance of Nit1 deficiency to human cancers was examined in human esophageal cancer tissues, and loss of Nit1 expression was observed in 48% of esophageal adenocarcinomas. (c) 2009 Wiley-Liss, Inc.

  17. Tumor suppressor CADM1 is involved in epithelial cell structure.

    Science.gov (United States)

    Sakurai-Yageta, Mika; Masuda, Mari; Tsuboi, Yumi; Ito, Akihiko; Murakami, Yoshinori

    2009-12-18

    The tumor suppressor, CADM1, is involved in cell adhesion and preferentially inactivated in invasive cancer. We have previously reported that CADM1 associates with an actin-binding protein, 4.1B/DAL-1, and a scaffold protein, membrane protein palmitoylated 3 (MPP3)/DLG3. However, underlying mechanism of tumor suppression by CADM1 is not clarified yet. Here, we demonstrate that MPP1/p55 and MPP2/DLG2, as well as MPP3, interact with both CADM1 and 4.1B, forming a tripartite complex. We then examined cell biological roles of CADM1 and its complex in epithelia using HEK293 cells. Among MPP1-3, MPP2 is recruited to the CADM1-4.1B complex in the early process of adhesion in HEK293 cells. By suppression of CADM1 expression using siRNA, HEK293 lose epithelia-like structure and show flat morphology with immature cell adhesion. 4.1B and MPP2, as well as E-cadherin and ZO-1, are mislocalized from the membrane by depletion of CADM1 in HEK293. Mislocalization of MPP2 is also observed in several cancer cells lacking CADM1 expression with the transformed morphology. These findings suggest that CADM1 is involved in the formation of epithelia-like cell structure with 4.1B and MPP2, while loss of its function could cause morphological transformation of cancer cells.

  18. Tumor Suppressor Function of CYLD in Nonmelanoma Skin Cancer

    Directory of Open Access Journals (Sweden)

    K. C. Masoumi

    2011-01-01

    Full Text Available Ubiquitin and ubiquitin-related proteins posttranslationally modify substrates, and thereby alter the functions of their targets. The ubiquitination process is involved in various physiological responses, and dysregulation of components of the ubiquitin system has been linked to many diseases including skin cancer. The ubiquitin pathways activated among skin cancers are highly diverse and may reflect the various characteristics of the cancer type. Basal cell carcinoma and squamous cell carcinoma, the most common types of human skin cancer, are instances where the involvement of the deubiquitination enzyme CYLD has been recently highlighted. In basal cell carcinoma, the tumor suppressor protein CYLD is repressed at the transcriptional levels through hedgehog signaling pathway. Downregulation of CYLD in basal cell carcinoma was also shown to interfere with TrkC expression and signaling, thereby promoting cancer progression. By contrast, the level of CYLD is unchanged in squamous cell carcinoma, instead, catalytic inactivation of CYLD in the skin has been linked to the development of squamous cell carcinoma. This paper will focus on the current knowledge that links CYLD to nonmelanoma skin cancers and will explore recent insights regarding CYLD regulation of NF-κB and hedgehog signaling during the development and progression of these types of human tumors.

  19. SIRT3: Oncogene and Tumor Suppressor in Cancer

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    Margalida Torrens-Mas

    2017-07-01

    Full Text Available Sirtuin 3 (SIRT3, the major deacetylase in mitochondria, plays a crucial role in modulating oxygen reactive species (ROS and limiting the oxidative damage in cellular components. SIRT3 targets different enzymes which regulate mitochondrial metabolism and participate in ROS detoxification, such as the complexes of the respiratory chain, the isocitrate dehydrogenase, or the manganese superoxide dismutase. Thus, SIRT3 activity is essential in maintaining mitochondria homeostasis and has recently received great attention, as it is considered a fidelity protein for mitochondrial function. In some types of cancer, SIRT3 functions as a tumoral promoter, since it keeps ROS levels under a certain threshold compatible with cell viability and proliferation. On the contrary, other studies describe SIRT3 as a tumoral suppressor, as SIRT3 could trigger cell death under stress conditions. Thus, SIRT3 could have a dual role in cancer. In this regard, modulation of SIRT3 activity could be a new target to develop more personalized therapies against cancer.

  20. Sirt3 is a tumor suppressor in lung adenocarcinoma cells.

    Science.gov (United States)

    Xiao, Kui; Jiang, Jiehan; Wang, Wei; Cao, Shan; Zhu, Liming; Zeng, Huihui; Ouyang, Ruoyun; Zhou, Rui; Chen, Ping

    2013-09-01

    Sirt3, a member of the mammalian sirtuin family protein that is localized to mitochondria, is a NAD+-dependent deacetylase and plays an important role in the control of metabolic activity. Recently, several studies have shown the potential role of Sirt3 in certain types of tumors such as breast cancer and hepatocellular carcinoma. However, the role of Sirt3 in lung adenocarcinoma has never been studied. In the present study, we found that Sirt3 protein expression was downregulated in human lung adenocarcinoma tissue when compared with that in adjacent normal tissue. Overexpression of Sirt3 using adenovirus significantly inhibited the growth of the A549 lung adenocarcinoma cell line. In this cell line, overexpression of Sirt3 induced apoptosis, which was evidenced by Annexin V + PI assay and cleaved caspase-3 immunoblotting. Furthermore, overexpression of Sirt3 increased the bax/bcl-2 and bad/bcl-x/L ratios, and promoted AIF translocation to the nucleus. Finally, Sirt3 overexpression upregulated p53 and p21 protein levels, and decreased intracellular ROS levels. Collectively, our data suggest that Sirt3 is a tumor suppressor in lung adenocarcinoma development and progression and may be a promising therapeutic target for lung adenocarcinoma.

  1. Tropomyosin-1, A Putative Tumor-Suppressor and a Biomarker of Human Breast Cancer

    Science.gov (United States)

    2004-10-01

    cDNA. Lobular carcinoma - 2 A polyclonal pan-TM antibody that recognizes multiple TM Phyllodes tumor - 1 Not determined from the initial pathology...AD Award Number: DAMD17-98-1-8162 TITLE: Tropomyosin-1, A Putative Tumor -Suppressor and a Biomarker of Human Breast Cancer PRINCIPAL INVESTIGATOR...4. TITLE AND SUBTITLE 5. FUNDING NUMBERS Tropomyosin-l, A Putative Tumor -Suppressor and a Biomarker DAMD17-98-1-8162 of Human Breast Cancer 6. A UTHOR

  2. Expression of the p16{sup INK4a} tumor suppressor gene in rodent lung tumors

    Energy Technology Data Exchange (ETDEWEB)

    Swafford, D.S.; Tesfaigzi, J.; Belinsky, S.A.

    1995-12-01

    Aberrations on the short arm of chromosome 9 are among the earliest genetic changes in human cancer. p16{sup INK4a} is a candidate tumor suppressor gene that lies within human 9p21, a chromosome region associated with frequent loss of heterozygosity in human lung tumors. The p16{sup INK4a} protein functions as an inhibitor of cyclin D{sub 1}-dependent kinases that phosphorylate the retinoblastoma (Rb) tumor suppressor gene product enabling cell-cycle progression. Thus, overexpression of cyclin D{sub 1}, mutation of cyclin-dependent kinase genes, or loss of p16{sup INK4a} function, can all result in functional inactivation of Rb. Inactivation of Rb by mutation or deletion can result in an increase in p16{sup INK4a} transcription, suggesting that an increased p16{sup INK4a} expression in a tumor cell signals dysfunction of the pathway. The p16{sup (INK4a)} gene, unlike some tumor suppressor genes, is rarely inactivated by mutation. Instead, the expression of this gene is suppressed in some human cancers by hypermethylation of the CpG island within the first exon or by homozygous deletion: 686. Chromosome losses have been observed at 9p21 syntenic loci in tumors of the mouse and rat, two species often used as animal models for pulmonary carcinogenesis. Expression of p16{sup INK4a} is lost in some mouse tumor cell lines, often due to homozygous deletion. These observations indicate that p16{sup INK4a} dysfunction may play a role in the development of neoplasia in rodents as well as humans. The purpose of the current investigation was to define the extent to which p16{sup INK4a} dysfunction contributes to the development of rodent lung tumors and to determine the mechanism of inactivation of the gene. There is no evidence to suggest a loss of function of the p16{sup INK4a} tumor suppressor gene in these primary murine lung tumors by mutation, deletion, or methylation.

  3. Methylation of the tumor suppressor protein, BRCA1, influences its transcriptional cofactor function.

    Directory of Open Access Journals (Sweden)

    Irene Guendel

    Full Text Available BACKGROUND: Approximately half of hereditary breast cancers have mutations in either BRCA1 or BRCA2. BRCA1 is a multifaceted tumor suppressor protein that has implications in processes such as cell cycle, transcription, DNA damage response and chromatin remodeling. This multifunctional nature of BRCA1 is achieved by exerting its many effects through modulation of transcription. Many cellular events are dictated by covalent modification of proteins, an important mechanism in regulating protein and genome function; of which protein methylation is an important posttranslational modification with activating or repressive effects. METHODS/PRINCIPAL FINDINGS: Here we demonstrate for the first time that BRCA1 is methylated both in breast cancer cell lines and breast cancer tumor samples at arginine and lysine residues through immunoprecipitation and western blot analysis. Arginine methylation by PRMT1 was observed in vitro and the region of BRCA1 504-802 shown to be highly methylated. PRMT1 was detected in complex with BRCA1 504-802 through in vitro binding assays and co-immunoprecipitated with BRCA1. Inhibition of methylation resulted in decreased BRCA1 methylation and alteration of BRCA1 binding to promoters in vivo as shown through chromatin immunoprecipitation assays. Knockdown of PRMT1 also resulted in increased BRCA1 binding to particular promoters in vivo. Finally, following methylation inhibition, Sp1 was found to preferentially associate with hypo-methylated BRCA1 and STAT1 was found to preferentially associate with hyper-methylated BRCA1. CONCLUSIONS/SIGNIFICANCE: These results suggest that methylation may influence either the ability of BRCA1 to bind to specific promoters or protein-protein interactions which alters the recruitment of BRCA1 to these promoters. Thus, given the importance of BRCA1 to genomic stability, methylation of BRCA1 may ultimately affect the tumor suppressor ability of BRCA1.

  4. PML tumor suppressor protein is required for HCV production

    Energy Technology Data Exchange (ETDEWEB)

    Kuroki, Misao [Department of Tumor Virology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, 2-5-1, Shikata-cho, Okayama 700-8558 (Japan); Research Fellow of the Japan Society for the Promotion of Science (Japan); Center for AIDS Research, Kumamoto University, Kumamoto 860-0811 (Japan); Ariumi, Yasuo, E-mail: ariumi@kumamoto-u.ac.jp [Department of Tumor Virology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, 2-5-1, Shikata-cho, Okayama 700-8558 (Japan); Center for AIDS Research, Kumamoto University, Kumamoto 860-0811 (Japan); Hijikata, Makoto [Department of Viral Oncology, Institute for Virus Research, Kyoto University, Kyoto 606-8507 (Japan); Ikeda, Masanori; Dansako, Hiromichi [Department of Tumor Virology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, 2-5-1, Shikata-cho, Okayama 700-8558 (Japan); Wakita, Takaji [Department of Virology II, National Institute of Infectious Diseases, Tokyo 162-8640 (Japan); Shimotohno, Kunitada [Research Center for Hepatitis and Immunology, National Center for Global Health and Medicine, Ichikawa, Chiba 272-8516 (Japan); Kato, Nobuyuki [Department of Tumor Virology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, 2-5-1, Shikata-cho, Okayama 700-8558 (Japan)

    2013-01-11

    Highlights: Black-Right-Pointing-Pointer PML tumor suppressor protein is required for HCV production. Black-Right-Pointing-Pointer PML is dispensable for HCV RNA replication. Black-Right-Pointing-Pointer HCV could not alter formation of PML-NBs. Black-Right-Pointing-Pointer INI1 and DDX5, PML-related proteins, are involved in HCV life cycle. -- Abstract: PML tumor suppressor protein, which forms discrete nuclear structures termed PML-nuclear bodies, has been associated with several cellular functions, including cell proliferation, apoptosis and antiviral defense. Recently, it was reported that the HCV core protein colocalizes with PML in PML-NBs and abrogates the PML function through interaction with PML. However, role(s) of PML in HCV life cycle is unknown. To test whether or not PML affects HCV life cycle, we examined the level of secreted HCV core and the infectivity of HCV in the culture supernatants as well as the level of HCV RNA in HuH-7-derived RSc cells, in which HCV-JFH1 can infect and efficiently replicate, stably expressing short hairpin RNA targeted to PML. In this context, the level of secreted HCV core and the infectivity in the supernatants from PML knockdown cells was remarkably reduced, whereas the level of HCV RNA in the PML knockdown cells was not significantly affected in spite of very effective knockdown of PML. In fact, we showed that PML is unrelated to HCV RNA replication using the subgenomic HCV-JFH1 replicon RNA, JRN/3-5B. Furthermore, the infectivity of HCV-like particle in the culture supernatants was significantly reduced in PML knockdown JRN/3-5B cells expressing core to NS2 coding region of HCV-JFH1 genome using the trans-packaging system. Finally, we also demonstrated that INI1 and DDX5, the PML-related proteins, are involved in HCV production. Taken together, these findings suggest that PML is required for HCV production.

  5. RASSF6; the Putative Tumor Suppressor of the RASSF Family

    Directory of Open Access Journals (Sweden)

    Hiroaki Iwasa

    2015-12-01

    Full Text Available Humans have 10 genes that belong to the Ras association (RA domain family (RASSF. Among them, RASSF7 to RASSF10 have the RA domain in the N-terminal region and are called the N-RASSF proteins. In contradistinction to them, RASSF1 to RASSF6 are referred to as the C-RASSF proteins. The C-RASSF proteins have the RA domain in the middle region and the Salvador/RASSF/Hippo domain in the C-terminal region. RASSF6 additionally harbors the PSD-95/Discs large/ZO-1 (PDZ-binding motif. Expression of RASSF6 is epigenetically suppressed in human cancers and is generally regarded as a tumor suppressor. RASSF6 induces caspase-dependent and -independent apoptosis. RASSF6 interacts with mammalian Ste20-like kinases (homologs of Drosophila Hippo and cross-talks with the Hippo pathway. RASSF6 binds MDM2 and regulates p53 expression. The interactions with Ras and Modulator of apoptosis 1 (MOAP1 are also suggested by heterologous protein-protein interaction experiments. RASSF6 regulates apoptosis and cell cycle through these protein-protein interactions, and is implicated in the NF-κB and JNK signaling pathways. We summarize our current knowledge about RASSF6 and discuss what common and different properties RASSF6 and the other C-RASSF proteins have.

  6. Breast Cancer Stem Cells and Tumor Suppressor Genes

    Directory of Open Access Journals (Sweden)

    Wendy W. Hwang-Verslues

    2008-10-01

    Full Text Available Studies of breast cancer stem cells are in their infancy and many fundamental questions have yet to be fully addressed. The molecular distinction between normal and cancerous breast stem cells is not clear. While there have been recent breakthroughs in mouse mammary stem cells and lineage determination in mammary glands, little has been determined in human cells. Microarray analyses have provided molecular categorization of breast cancer. However, the cellular origin of different types of breast cancer is largely unknown. In addition, the relationship between breast cancer stem cells and mammary progenitor cells has yet to be clarified. One of the key questions is how a normal mammary stem cell becomes a breast cancer stem cell. Importantly, the existence of different types of human breast cancers with distinct pathologic and molecular signatures suggests the possibility that different types of breast cancer stem cells may exist. Here, we aim to review the current evidence for the existence of different subtypes of breast cancer stem cells and provide further insight into how tumor suppressors might be involved in the initiation of breast cancer stem cells.

  7. The FHIT gene product: tumor suppressor and genome "caretaker".

    Science.gov (United States)

    Waters, Catherine E; Saldivar, Joshua C; Hosseini, Seyed Ali; Huebner, Kay

    2014-12-01

    The FHIT gene at FRA3B is one of the earliest and most frequently altered genes in the majority of human cancers. It was recently discovered that the FHIT gene is not the most fragile locus in epithelial cells, the cell of origin for most Fhit-negative cancers, eroding support for past claims that deletions at this locus are simply passenger events that are carried along in expanding cancer clones, due to extreme vulnerability to DNA damage rather than to loss of FHIT function. Indeed, recent reports have reconfirmed FHIT as a tumor suppressor gene with roles in apoptosis and prevention of the epithelial-mesenchymal transition. Other recent works have identified a novel role for the FHIT gene product, Fhit, as a genome "caretaker." Loss of this caretaker function leads to nucleotide imbalance, spontaneous replication stress, and DNA breaks. Because Fhit loss-induced DNA damage is "checkpoint blind," cells accumulate further DNA damage during subsequent cell cycles, accruing global genome instability that could facilitate oncogenic mutation acquisition and expedite clonal expansion. Loss of Fhit activity therefore induces a mutator phenotype. Evidence for FHIT as a mutator gene is discussed in light of these recent investigations of Fhit loss and subsequent genome instability.

  8. CHIP is a novel tumor suppressor in pancreatic cancer and inhibits tumor growth through targeting EGFR

    Science.gov (United States)

    Wang, Tianxiao; Yang, Jingxuan; Xu, Jianwei; Li, Jian; Cao, Zhe; Zhou, Li; You, Lei; Shu, Hong; Lu, Zhaohui; Li, Huihua; Li, Min; Zhang, Taiping; Zhao, Yupei

    2014-01-01

    Carboxyl terminus of heat shock protein 70-interacting protein (CHIP) is an E3 ubiquitin ligase that is involved in protein quality control and mediates several tumor-related proteins in many cancers, but the function of CHIP in pancreatic cancer is not known. Here we show that CHIP interacts and ubiquitinates epidermal growth factor receptor (EGFR) for proteasome-mediated degradation in pancreatic cancer cells, thereby inhibiting the activation of EGFR downstream pathways. CHIP suppressed cell proliferation, anchor-independent growth, invasion and migration, as well as enhanced apoptosis induced by erlotinib in vitro and in vivo. The expression of CHIP was decreased in pancreatic cancer tissues or sera. Low CHIP expression in tumor tissues was correlated with tumor differentiation and shorter overall survival. These observations indicate that CHIP serves as a novel tumor suppressor by down-regulating EGFR pathway in pancreatic cancer cells, decreased expression of CHIP was associated with poor prognosis in pancreatic cancer. PMID:24722501

  9. The Role of Tumor Metastases Suppressor Gene, Drg-1, in Breast Cancer

    Science.gov (United States)

    2008-03-01

    catenin. Nuclear staining beta-catenin 36 72 Breast Carcinoma Phyllodes tumor 73 74 75 Reduced...AD_________________ Award Number: W81XWH-05-1-0309 TITLE: The Role of Tumor Metastases Suppressor...TYPE Annual 3. DATES COVERED (From - To) 1 MAR 2007 - 29 FEB 2008 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER The Role of Tumor Metastases

  10. A functional dissection of PTEN N-terminus: implications in PTEN subcellular targeting and tumor suppressor activity.

    Science.gov (United States)

    Gil, Anabel; Rodríguez-Escudero, Isabel; Stumpf, Miriam; Molina, María; Cid, Víctor J; Pulido, Rafael

    2015-01-01

    Spatial regulation of the tumor suppressor PTEN is exerted through alternative plasma membrane, cytoplasmic, and nuclear subcellular locations. The N-terminal region of PTEN is important for the control of PTEN subcellular localization and function. It contains both an active nuclear localization signal (NLS) and an overlapping PIP2-binding motif (PBM) involved in plasma membrane targeting. We report a comprehensive mutational and functional analysis of the PTEN N-terminus, including a panel of tumor-related mutations at this region. Nuclear/cytoplasmic partitioning in mammalian cells and PIP3 phosphatase assays in reconstituted S. cerevisiae defined categories of PTEN N-terminal mutations with distinct PIP3 phosphatase and nuclear accumulation properties. Noticeably, most tumor-related mutations that lost PIP3 phosphatase activity also displayed impaired nuclear localization. Cell proliferation and soft-agar colony formation analysis in mammalian cells of mutations with distinctive nuclear accumulation and catalytic activity patterns suggested a contribution of both properties to PTEN tumor suppressor activity. Our functional dissection of the PTEN N-terminus provides the basis for a systematic analysis of tumor-related and experimentally engineered PTEN mutations.

  11. Trophoblast expression dynamics of the tumor suppressor gene gastrokine 2.

    Science.gov (United States)

    Fahlbusch, Fabian B; Ruebner, Matthias; Huebner, Hanna; Volkert, Gudrun; Bartunik, Hannah; Winterfeld, Ilona; Hartner, Andrea; Menendez-Castro, Carlos; Noegel, Stephanie C; Marek, Ines; Wachter, David; Schneider-Stock, Regine; Beckmann, Matthias W; Kehl, Sven; Rascher, Wolfgang

    2015-09-01

    Gastrokines (GKNs) were originally described as stomach-specific tumor suppressor genes. Recently, we identified GKN1 in extravillous trophoblasts (EVT) of human placenta. GKN1 treatment reduced the migration of the trophoblast cell line JEG-3. GKN2 is known to inhibit the proliferation, migration and invasion of gastric cancer cells and may interact with GKN1. Recently, GKN2 was detected in the placental yolk sac of mice. We therefore aimed to further characterize placental GKN2 expression. By immunohistochemistry, healthy first-trimester placenta showed ubiquitous staining for GKN2 at its early gestational stage. At later gestational stages, a more differentiated expression pattern in EVT and villous cytotrophoblasts became evident. In healthy third-trimester placenta, only EVT retained strong GKN2 immunoreactivity. In contrast, HELLP placentas showed a tendency of increased levels of GKN2 expression with a more prominent GKN2 staining in their syncytiotrophoblast. Choriocarcinoma cell lines did not express GKN2. Besides its trophoblastic expression, we found human GKN2 in fibrotic villi, in amniotic membrane and umbilical cord. GKN2 co-localized with smooth muscle actin in villous myofibroblasts and with HLA-G and GKN1 in EVT. In the rodent placenta, GKN2 was specifically located in the spongiotrophoblast layer. Thus, the gestational age-dependent and compartment-specific expression pattern of GKN2 points to a role for placental development. The syncytial expression of GKN2 in HELLP placentas might represent a reduced state of functional differentiation of the syncytiotrophoblast. Moreover, the specific GKN2 expression in the rodent spongiotrophoblast layer (equivalent to human EVT) might suggest an important role in EVT physiology.

  12. Metastasis Suppressor Genes: At the Interface Between the Environment and Tumor Cell Growth

    Science.gov (United States)

    Hurst, Douglas R.; Welch, Danny R.

    2013-01-01

    The molecular mechanisms and genetic programs required for cancer metastasis are sometimes overlapping, but components are clearly distinct from those promoting growth of a primary tumor. Every sequential, rate-limiting step in the sequence of events leading to metastasis requires coordinated expression of multiple genes, necessary signaling events, and favorable environmental conditions or the ability to escape negative selection pressures. Metastasis suppressors are molecules that inhibit the process of metastasis without preventing growth of the primary tumor. The cellular processes regulated by metastasis suppressors are diverse and function at every step in the metastatic cascade. As we gain knowledge into the molecular mechanisms of metastasis suppressors and cofactors with which they interact, we learn more about the process, including appreciation that some are potential targets for therapy of metastasis, the most lethal aspect of cancer. Until now, metastasis suppressors have been described largely by their function. With greater appreciation of their biochemical mechanisms of action, the importance of context is increasingly recognized especially since tumor cells exist in myriad microenvironments. In this review, we assemble the evidence that selected molecules are indeed suppressors of metastasis, collate the data defining the biochemical mechanisms of action, and glean insights regarding how metastasis suppressors regulate tumor cell communication to–from microenvironments. PMID:21199781

  13. Tumor Suppressor Inactivation in the Pathogenesis of Adult T-Cell Leukemia

    Directory of Open Access Journals (Sweden)

    Christophe Nicot

    2015-01-01

    Full Text Available Tumor suppressor functions are essential to control cellular proliferation, to activate the apoptosis or senescence pathway to eliminate unwanted cells, to link DNA damage signals to cell cycle arrest checkpoints, to activate appropriate DNA repair pathways, and to prevent the loss of adhesion to inhibit initiation of metastases. Therefore, tumor suppressor genes are indispensable to maintaining genetic and genomic integrity. Consequently, inactivation of tumor suppressors by somatic mutations or epigenetic mechanisms is frequently associated with tumor initiation and development. In contrast, reactivation of tumor suppressor functions can effectively reverse the transformed phenotype and lead to cell cycle arrest or death of cancerous cells and be used as a therapeutic strategy. Adult T-cell leukemia/lymphoma (ATLL is an aggressive lymphoproliferative disease associated with infection of CD4 T cells by the Human T-cell Leukemia Virus Type 1 (HTLV-I. HTLV-I-associated T-cell transformation is the result of a multistep oncogenic process in which the virus initially induces chronic T-cell proliferation and alters cellular pathways resulting in the accumulation of genetic defects and the deregulated growth of virally infected cells. This review will focus on the current knowledge of the genetic and epigenetic mechanisms regulating the inactivation of tumor suppressors in the pathogenesis of HTLV-I.

  14. Expansion and functions of myeloid-derived suppressor cells in the tumor microenvironment.

    Science.gov (United States)

    Qu, Peng; Wang, Li-Zhen; Lin, P Charles

    2016-09-28

    Myeloid derived suppressor cells (MDSCs) are a group of immature myeloid cells accumulated in most cancer patients and mouse tumor models. MDSCs suppress host immune response and concurrently promote tumor angiogenesis, thereby promote tumor growth and progression. In this review, we discuss recent progresses in expansion and activity of tumor MDSCs, and describe new findings about immunosuppressive function of different subtypes of MDSCs in cancer. We also discussed tumor angiogenic activities and pro-tumor invasion/metastatic roles of MDSCs in tumor progression. Published by Elsevier Ireland Ltd.

  15. The human ARF tumor suppressor senses blastema activity and suppresses epimorphic tissue regeneration

    Science.gov (United States)

    Hesse, Robert G; Kouklis, Gayle K; Ahituv, Nadav; Pomerantz, Jason H

    2015-01-01

    The control of proliferation and differentiation by tumor suppressor genes suggests that evolution of divergent tumor suppressor repertoires could influence species’ regenerative capacity. To directly test that premise, we humanized the zebrafish p53 pathway by introducing regulatory and coding sequences of the human tumor suppressor ARF into the zebrafish genome. ARF was dormant during development, in uninjured adult fins, and during wound healing, but was highly expressed in the blastema during epimorphic fin regeneration after amputation. Regenerative, but not developmental signals resulted in binding of zebrafish E2f to the human ARF promoter and activated conserved ARF-dependent Tp53 functions. The context-dependent activation of ARF did not affect growth and development but inhibited regeneration, an unexpected distinct tumor suppressor response to regenerative versus developmental environments. The antagonistic pleiotropic characteristics of ARF as both tumor and regeneration suppressor imply that inducing epimorphic regeneration clinically would require modulation of ARF –p53 axis activation. DOI: http://dx.doi.org/10.7554/eLife.07702.001 PMID:26575287

  16. Tumor suppressor roles of CENP-E and Nsl1 in Drosophila epithelial tissues.

    Science.gov (United States)

    Clemente-Ruiz, Marta; Muzzopappa, Mariana; Milán, Marco

    2014-01-01

    Depletion of spindle assembly checkpoint (SAC) genes in Drosophila epithelial tissues leads to JNK-dependent programmed cell death and additional blockade of the apoptotic program drives tumorigenesis. A recent report proposes that chromosomal instability (CIN) is not the driving force in the tumorigenic response of the SAC-deficient tissue, and that checkpoint proteins exert a SAC-independent tumor suppressor role. This notion is based on observations that the depletion of CENP-E levels or prevention of Bub3 from binding to the kinetochore in Drosophila tissues unable to activate the apoptotic program induces CIN but does not cause hyperproliferation. Here we re-examined this proposal. In contrast to the previous report, we observed that depletion of CENP-E or Nsl1-the latter mediating kinetochore targeting of Bub3-in epithelial tissues unable to activate the apoptotic program induces significant levels of aneuploidy and drives tumor-like growth. The induction of the JNK transcriptional targets Wingless, a mitogenic molecule, and MMP1, a matrix metaloproteinase 1 involved in basement membrane degradation was also observed in these tumors. An identical response of the tissue was previously detected upon depletion of several SAC genes or genes involved in spindle assembly, chromatin condensation, and cytokinesis, all of which have been described to cause CIN. All together, these results reinforce the role of CIN in driving tumorigenesis in Drosophila epithelial tissues and question the proposed SAC-independent roles of checkpoint proteins in suppressing tumorigenesis. Differences in aneuploidy rates might explain the discrepancy between the previous report and our results.

  17. Long noncoding RNA TSLNC8 is a tumor suppressor that inactivates the interleukin-6/STAT3 signaling pathway.

    Science.gov (United States)

    Zhang, Jiwei; Li, Zhe; Liu, Longzi; Wang, Qifeng; Li, Shengli; Chen, Di; Hu, Zhixiang; Yu, Tao; Ding, Jie; Li, Jinjun; Yao, Ming; Huang, Shenglin; Zhao, Yingjun; He, Xianghuo

    2018-01-01

    Long noncoding RNAs can serve as oncogenes or tumor suppressors in human cancer; however, their biological functions and underlying mechanism in hepatocarcinogenesis are largely unknown. Here, we report a novel tumor suppressor long noncoding RNA on chromosome 8p12 (termed TSLNC8) that is frequently deleted and down-regulated in hepatocellular carcinoma (HCC) tissues. The loss of TSLNC8 is highly associated with the malignant features of HCC and serves as a prognostic indicator for HCC patients. TSLNC8 significantly suppresses the proliferation and metastasis of HCC cells in vitro and in vivo. TSLNC8 exerts its tumor suppressive activity by competitively interacting with transketolase and signal transducer and activator of transcription 3 (STAT3) and modulating the STAT3-Tyr705 and STAT3-Ser727 phosphorylation levels and STAT3 transcriptional activity, thus resulting in inactivation of the interleukin-6-STAT3 signaling pathway in HCC cells. TSLNC8 is a promising prognostic predictor for patients with HCC, and the TSLNC8-transketolase-STAT3 axis is a potential therapeutic target for HCC treatment. (Hepatology 2018;67:171-187). © 2017 by the American Association for the Study of Liver Diseases.

  18. Correlation of primary tumor size and axillary nodal status with tumor suppressor gene p53 in breast carcinoma

    Directory of Open Access Journals (Sweden)

    Topić Brano

    2002-01-01

    Full Text Available Correlation of standard path morphological prognostic parameters, primary tumor size and axillary nodal status with new prognostic factor in breast carcinoma: tumor suppressor gene p53 was analyzed. The studied sample included 65 women who underwent surgery for breast carcinoma at the Surgical Clinic of Clinical Center Banja Luka, from January 1st 1997 till January 1st 1999. Statistical data analysis was performed and correlation of prognostic factors was determined. The majority of authors in this field agree that the primary tumor size and axillary nodal status are the two most important prognostic factors. These factors are the best predictors of prognosis and survival of women who had the tumor and were operated on. Tumor markers were immunohistochemically determined in the last ten years and, according to the majority of authors, are still considered the additional or relative prognostic factors in breast carcinoma. Their prognostic value and significance increase almost daily. Most frequently determined tumor markers are bcl-2, pS2, Ki-67 and p53. There was a positive, directly proportional relationship between primary tumor size and tumor suppressor gene p53, but there was no positive correlation between the axillary nodal status and tumor suppressor gene p53. Significance of determination of new tumor markers as the prognostic factors was emphasized. These markers represent a powerful tool in the early detection and prevention of breast carcinoma.

  19. The potential for tumor suppressor gene therapy in head and neck cancer.

    Science.gov (United States)

    Birkeland, Andrew C; Ludwig, Megan L; Spector, Matthew E; Brenner, J Chad

    2016-01-01

    Head and neck squamous cell carcinoma remains a highly morbid and fatal disease. Importantly, genomic sequencing of head and neck cancers has identified frequent mutations in tumor suppressor genes. While targeted therapeutics increasingly are being investigated in head and neck cancer, the majority of these agents are against overactive/overexpressed oncogenes. Therapy to restore lost tumor suppressor gene function remains a key and under-addressed niche in trials for head and neck cancer. Recent advances in gene editing have captured the interest of both the scientific community and the public. As our technology for gene editing and gene expression modulation improves, addressing lost tumor suppressor gene function in head and neck cancers is becoming a reality. This review will summarize new techniques, challenges to implementation, future directions, and ethical ramifications of gene therapy in head and neck cancer.

  20. Induction of Suppressor Cells and Increased Tumor Growth following Chronic Psychosocial Stress in Male Mice.

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    Dominic Schmidt

    Full Text Available To study the impact of psychosocial stress on the immune system, male mice were subjected to chronic subordinate colony housing (CSC, a preclinically validated mouse model for chronic psychosocial stress. CSC substantially affected the cell composition of the bone marrow, blood, and spleen by inducing myelopoiesis and enhancing the frequency of regulatory T cells in the CD4 population. Expansion of the myeloid cell compartment was due to cells identified as immature inflammatory myeloid cells having the phenotype of myeloid-derived suppressor cells of either the granulocytic or the monocytic type. Catecholaminergic as well as TNF signaling were implicated in these CSC-induced cellular shifts. Although the frequency of regulatory cells was enhanced following CSC, the high capacity for inflammatory cytokine secretion of total splenocytes indicated an inflammatory immune status in CSC mice. Furthermore, CSC enhanced the suppressive activity of bone marrow-derived myeloid-derived suppressor cells towards proliferating T cells. In line with the occurrence of suppressor cell types such as regulatory T cells and myeloid-derived suppressor cells, transplanted syngeneic fibrosarcoma cells grew better in CSC mice than in controls, a process accompanied by pronounced angiogenesis and clustering of immature myeloid cells in the tumor tissue. In addition, tumor implantation after CSC reinforced the CSC-induced increase in myeloid-derived suppressor cells and regulatory T cell frequencies while the CSC-induced cellular changes eased off in mice without tumor. Together, our data suggest a role for suppressor cells such as regulatory T cells and myeloid-derived suppressor cells in the enhanced tumor growth after chronic psychosocial stress.

  1. E2F-HDAC complexes negatively regulate the tumor suppressor gene ARHI in breast cancer

    DEFF Research Database (Denmark)

    Lu, Z; Luo, R Z; Peng, H

    2006-01-01

    ARHI is a maternally imprinted tumor suppressor gene whose expression is markedly downregulated in breast cancer. Reactivation of ARHI expression in breast cancer cells is associated with increased histone H3 acetylation and decreased lysine 9 methylation of histone H3. An ARHI promoter segment...... of the tumor suppressor gene ARHI in breast cancer cells....... that spanned bases -420 to +58 (designated the P2 region) exhibits significantly higher promoter activity in normal cells than in cancer cells. To better understand the molecular mechanisms contributing to this differential transcriptional activity, we sought to identify transcription factors that bind...

  2. Multiplexed methylation profiles of tumor suppressor genes and clinical outcome in lung cancer

    Directory of Open Access Journals (Sweden)

    Venditti Julio

    2010-09-01

    Full Text Available Abstract Background Changes in DNA methylation of crucial cancer genes including tumor suppressors can occur early in carcinogenesis, being potentially important early indicators of cancer. The objective of this study was to examine a multiplexed approach to assess the methylation of tumor suppressor genes as tumor stratification and clinical outcome prognostic biomarkers for lung cancer. Methods A multicandidate probe panel interrogated DNA for aberrant methylation status in 18 tumor suppressor genes in lung cancer using a methylation-specific multiplex ligation-dependent probe amplification assay (MS-MLPA. Lung cancer cell lines (n = 7, and primary lung tumors (n = 54 were examined using MS-MLPA. Results Genes frequently methylated in lung cancer cell lines including SCGB3A1, ID4, CCND2 were found among the most commonly methylated in the lung tumors analyzed. HLTF, BNIP3, H2AFX, CACNA1G, TGIF, ID4 and CACNA1A were identified as novel tumor suppressor candidates methylated in lung tumors. The most frequently methylated genes in lung tumors were SCGB3A1 and DLC1 (both 50.0%. Methylation rates for ID4, DCL1, BNIP3, H2AFX, CACNA1G and TIMP3 were significantly different between squamous and adenocarcinomas. Methylation of RUNX3, SCGB3A1, SFRP4, and DLC1 was significantly associated with the extent of the disease when comparing localized versus metastatic tumors. Moreover, methylation of HTLF, SFRP5 and TIMP3 were significantly associated with overall survival. Conclusions MS-MLPA can be used for classification of certain types of lung tumors and clinical outcome prediction. This latter is clinically relevant by offering an adjunct strategy for the clinical management of lung cancer patients.

  3. Macrophages, Inflammation, and Tumor Suppressors: ARF, a New Player in the Game

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    Paqui G. Través

    2012-01-01

    Full Text Available The interaction between tumor progression and innate immune system has been well established in the last years. Indeed, several lines of clinical evidence indicate that immune cells such as tumor-associated macrophages (TAMs interact with tumor cells, favoring growth, angiogenesis, and metastasis of a variety of cancers. In most tumors, TAMs show properties of an alternative polarization phenotype (M2 characterized by the expression of a series of chemokines, cytokines, and proteases that promote immunosuppression, tumor proliferation, and spreading of the cancer cells. Tumor suppressor genes have been traditionally linked to the regulation of cancer progression; however, a growing body of evidence indicates that these genes also play essential roles in the regulation of innate immunity pathways through molecular mechanisms that are still poorly understood. In this paper, we provide an overview of the immunobiology of TAMs as well as what is known about tumor suppressors in the context of immune responses. Recent advances regarding the role of the tumor suppressor ARF as a regulator of inflammation and macrophage polarization are also reviewed.

  4. Retinoid-induced expression and activity of an immediate early tumor suppressor gene in vascular smooth muscle cells.

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    Jeffrey W Streb

    2011-04-01

    Full Text Available Retinoids are used clinically to treat a number of hyper-proliferative disorders and have been shown in experimental animals to attenuate vascular occlusive diseases, presumably through nuclear receptors bound to retinoic acid response elements (RARE located in target genes. Here, we show that natural or synthetic retinoids rapidly induce mRNA and protein expression of a specific isoform of A-Kinase Anchoring Protein 12 (AKAP12β in cultured smooth muscle cells (SMC as well as the intact vessel wall. Expression kinetics and actinomycin D studies indicate Akap12β is a retinoid-induced, immediate-early gene. Akap12β promoter analyses reveal a conserved RARE mildly induced with atRA in a region that exhibits hyper-acetylation. Immunofluorescence microscopy and protein kinase A (PKA regulatory subunit overlay assays in SMC suggest a physical association between AKAP12β and PKA following retinoid treatment. Consistent with its designation as a tumor suppressor, inducible expression of AKAP12β attenuates SMC growth in vitro. Further, immunohistochemistry studies establish marked decreases in AKAP12 expression in experimentally-injured vessels of mice as well as atheromatous lesions in humans. Collectively, these results demonstrate a novel role for retinoids in the induction of an AKAP tumor suppressor that blocks vascular SMC growth thus providing new molecular insight into how retiniods may exert their anti-proliferative effects in the injured vessel wall.

  5. BASP1 is a transcriptional cosuppressor for the Wilms' tumor suppressor protein WT1

    DEFF Research Database (Denmark)

    Carpenter, Brian; Hill, Kathryn J; Charalambous, Marika

    2004-01-01

    The Wilms' tumor suppressor protein WT1 is a transcriptional regulator that plays a key role in the development of the kidneys. The transcriptional activation domain of WT1 is subject to regulation by a suppression region within the N terminus of WT1. Using a functional assay, we provide direct e...

  6. Enhancer-Mediated Oncogenic Function of the Menin Tumor Suppressor in Breast Cancer

    NARCIS (Netherlands)

    Dreijerink, Koen M A; Groner, Anna C.; Vos, Erica S M; Font-Tello, Alba; Gu, Lei; Chi, David; Reyes, Jaime; Cook, Jennifer; Lim, Elgene; Lin, Charles Y.; de Laat, Wouter; Rao, Prakash K.; Long, Henry W.; Brown, Myles

    2017-01-01

    While the multiple endocrine neoplasia type 1 (MEN1) gene functions as a tumor suppressor in a variety of cancer types, we explored its oncogenic role in breast tumorigenesis. The MEN1 gene product menin is involved in H3K4 trimethylation and co-activates transcription. We integrated ChIP-seq and

  7. Haploinsufficiency of the genes encoding the tumor suppressor Pten predisposes zebrafish to hemangiosarcoma

    NARCIS (Netherlands)

    Choorapoikayil, S.; Kuiper, R.V.; de Bruin, A.; den Hertog, J.

    2012-01-01

    PTEN is an essential tumor suppressor that antagonizes Akt/PKB signaling. The zebrafish genome encodes two Pten genes, ptena and ptenb. Here, we report that zebrafish mutants that retain a single wild-type copy of ptena or ptenb (ptena(+/-)ptenb(-/-) or ptena(-/-)ptenb(+/-)) are viable and fertile.

  8. The viral tropism of two distinct oncolytic viruses, reovirus and myxoma virus, is modulated by cellular tumor suppressor gene status.

    Science.gov (United States)

    Kim, M; Williamson, C T; Prudhomme, J; Bebb, D G; Riabowol, K; Lee, P W K; Lees-Miller, S P; Mori, Y; Rahman, M M; McFadden, G; Johnston, R N

    2010-07-08

    Replication-competent oncolytic viruses hold great potential for the clinical treatment of many cancers. Importantly, many oncolytic virus candidates, such as reovirus and myxoma virus, preferentially infect cancer cells bearing abnormal cellular signaling pathways. Reovirus and myxoma virus are highly responsive to activated Ras and Akt signaling pathways, respectively, for their specificity for viral oncolysis. However, considering the complexity of cancer cell populations, it is possible that other tumor-specific signaling pathways may also contribute to viral discrimination between normal versus cancer cells. Because carcinogenesis is a multistep process involving the accumulation of both oncogene activations and the inactivation of tumor suppressor genes, we speculated that not only oncogenes but also tumor suppressor genes may have an important role in determining the tropism of these viruses for cancer cells. It has been previously shown that many cellular tumor suppressor genes, such as p53, ATM and Rb, are important for maintaining genomic stability; dysfunction of these tumor suppressors may disrupt intact cellular antiviral activity due to the accumulation of genomic instability or due to interference with apoptotic signaling. Therefore, we speculated that cells with dysfunctional tumor suppressors may display enhanced susceptibility to challenge with these oncolytic viruses, as previously seen with adenovirus. We report here that both reovirus and myxoma virus preferentially infect cancer cells bearing dysfunctional or deleted p53, ATM and Rb tumor suppressor genes compared to cells retaining normal counterparts of these genes. Thus, oncolysis by these viruses may be influenced by both oncogenic activation and tumor suppressor status.

  9. KAT6B Is a Tumor Suppressor Histone H3 Lysine 23 Acetyltransferase Undergoing Genomic Loss in Small Cell Lung Cancer.

    Science.gov (United States)

    Simó-Riudalbas, Laia; Pérez-Salvia, Montserrat; Setien, Fernando; Villanueva, Alberto; Moutinho, Catia; Martínez-Cardús, Anna; Moran, Sebastian; Berdasco, Maria; Gomez, Antonio; Vidal, Enrique; Soler, Marta; Heyn, Holger; Vaquero, Alejandro; de la Torre, Carolina; Barceló-Batllori, Silvia; Vidal, August; Roz, Luca; Pastorino, Ugo; Szakszon, Katalin; Borck, Guntram; Moura, Conceição S; Carneiro, Fátima; Zondervan, Ilse; Savola, Suvi; Iwakawa, Reika; Kohno, Takashi; Yokota, Jun; Esteller, Manel

    2015-09-15

    Recent efforts to sequence human cancer genomes have highlighted that point mutations in genes involved in the epigenetic setting occur in tumor cells. Small cell lung cancer (SCLC) is an aggressive tumor with poor prognosis, where little is known about the genetic events related to its development. Herein, we have identified the presence of homozygous deletions of the candidate histone acetyltransferase KAT6B, and the loss of the corresponding transcript, in SCLC cell lines and primary tumors. Furthermore, we show, in vitro and in vivo, that the depletion of KAT6B expression enhances cancer growth, while its restoration induces tumor suppressor-like features. Most importantly, we demonstrate that KAT6B exerts its tumor-inhibitory role through a newly defined type of histone H3 Lys23 acetyltransferase activity. ©2015 American Association for Cancer Research.

  10. Transducer of ERBB2.1 (TOB1 as a Tumor Suppressor: A Mechanistic Perspective

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    Hun Seok Lee

    2015-12-01

    Full Text Available Transducer of ERBB2.1 (TOB1 is a tumor-suppressor protein, which functions as a negative regulator of the receptor tyrosine-kinase ERBB2. As most of the other tumor suppressor proteins, TOB1 is inactivated in many human cancers. Homozygous deletion of TOB1 in mice is reported to be responsible for cancer development in the lung, liver, and lymph node, whereas the ectopic overexpression of TOB1 shows anti-proliferation, and a decrease in the migration and invasion abilities on cancer cells. Biochemical studies revealed that the anti-proliferative activity of TOB1 involves mRNA deadenylation and is associated with the reduction of both cyclin D1 and cyclin-dependent kinase (CDK expressions and the induction of CDK inhibitors. Moreover, TOB1 interacts with an oncogenic signaling mediator, β-catenin, and inhibits β-catenin-regulated gene transcription. TOB1 antagonizes the v-akt murine thymoma viral oncogene (AKT signaling and induces cancer cell apoptosis by activating BCL2-associated X (BAX protein and inhibiting the BCL-2 and BCL-XL expressions. The tumor-specific overexpression of TOB1 results in the activation of other tumor suppressor proteins, such as mothers against decapentaplegic homolog 4 (SMAD4 and phosphatase and tensin homolog-10 (PTEN, and blocks tumor progression. TOB1-overexpressing cancer cells have limited potential of growing as xenograft tumors in nude mice upon subcutaneous implantation. This review addresses the molecular basis of TOB1 tumor suppressor function with special emphasis on its regulation of intracellular signaling pathways.

  11. Effect of hydroxyurea on the promoter occupancy profiles of tumor suppressor p53 and p73

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    Lu Xin

    2009-06-01

    Full Text Available Abstract Background The p53 tumor suppressor and its related protein, p73, share a homologous DNA binding domain, and mouse genetics studies have suggested that they have overlapping as well as distinct biological functions. Both p53 and p73 are activated by genotoxic stress to regulate an array of cellular responses. Previous studies have suggested that p53 and p73 independently activate the cellular apoptotic program in response to cytotoxic drugs. The goal of this study was to compare the promoter-binding activity of p53 and p73 at steady state and after genotoxic stress induced by hydroxyurea. Results We employed chromatin immunoprecipitation, the NimbleGen promoter arrays and a model-based algorithm for promoter arrays to identify promoter sequences enriched in anti-p53 or anti-p73 immunoprecipitates, either before or after treatment with hydroxyurea, which increased the expression of both p53 and p73 in the human colon cancer cell line HCT116-3(6. We calculated a model-based algorithm for promoter array score for each promoter and found a significant correlation between the promoter occupancy profiles of p53 and p73. We also found that after hydroxyurea treatment, the p53-bound promoters were still bound by p73, but p73 became associated with additional promoters that that did not bind p53. In particular, we showed that hydroxyurea induces the binding of p73 but not p53 to the promoter of MLH3, which encodes a mismatch repair protein, and causes an up-regulation of the MLH3 mRNA. Conclusion These results suggest that hydroxyurea exerts differential effects on the promoter-binding functions of p53 and p73 and illustrate the power of model-based algorithm for promoter array in the analyses of promoter occupancy profiles of highly homologous transcription factors.

  12. CMTM5 exhibits tumor suppressor activity through promoter methylation in oral squamous cell carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Heyu [Central Laboratory, Peking University School of Stomatology, Beijing (China); Nan, Xu [Center for Human Disease Genomics, Department of Immunology, Key Laboratory of Medical Immunology, Ministry of Health, School of Basic Medical Sciences, Peking University, Beijing (China); Li, Xuefen [Central Laboratory, Peking University School of Stomatology, Beijing (China); Chen, Yan; Zhang, Jianyun [Department of Oral Pathology, Peking University School of Stomatology, Beijing (China); Sun, Lisha [Central Laboratory, Peking University School of Stomatology, Beijing (China); Han, Wenlin [Center for Human Disease Genomics, Department of Immunology, Key Laboratory of Medical Immunology, Ministry of Health, School of Basic Medical Sciences, Peking University, Beijing (China); Li, Tiejun, E-mail: litiejun22@vip.sina.com [Department of Oral Pathology, Peking University School of Stomatology, Beijing (China)

    2014-05-02

    Highlights: • Down-regulation of CMTM5 expression in OSCC tissues was found. • The promoter methylation status of CMTM5 was measured. • CMTM5-v1 inhibited cell proliferation and migration and induced apoptosis. • CMTM5 might act as a putative tumor suppressor gene in OSCC. - Abstract: Oral squamous cell carcinoma (OSCC) is one of the most common types of malignancies in the head and neck region. CKLF-like MARVEL transmembrane domain-containing member 5 (CMTM5) has been recently implicated as a tumor suppressor gene in several cancer types. Herein, we examined the expression and function of CMTM5 in oral squamous cell carcinoma. CMTM5 was down-regulated in oral squamous cell lines and tumor samples from patients with promoter methylation. Treatment with the demethylating agent 5-aza-2′-deoxycytidine restored CMTM5 expression. In the OSCC cell lines CAL27 and GNM, the ectopic expression of CMTM5-v1 strongly inhibited cell proliferation and migration and induced apoptosis. In addition, CMTM5-v1 inhibited tumor formation in vivo. Therefore, CMTM5 might act as a putative tumor suppressor gene through promoter methylation in oral squamous cell carcinoma.

  13. Role of the ARF Tumor Suppressor in Prostate Cancer

    Science.gov (United States)

    2011-08-01

    Jr., Ph.D. 11 “Arf Loss Alters the Translatome to Permit Breast Cancer Research Group Transformation “ Washington University School of...Cell 4, 209-221 (2003) http://www.ncbi.nlm.nih.gov/pubmed/14522255. 10 Kladney, R. D. et al. Tuberous sclerosis complex 1: an epithelial tumor

  14. Structural Basis of Merlin Tumor Suppressor Functions in Neurofibromatosis-2

    Science.gov (United States)

    2014-12-01

    recombinant proteins due to an N-terminal peptide encoding Saccharomyces cerevisiae secretion signal. We generated constructs harboring a C-terminal...junctions, provoking uncontrolled cell growth and leading to the development of ultimately lethal tumors, including schwannoma, meningioma, and...uncontrolled growth , loss of contact inhibition, and alterations in the expression of mitogenic signaling cell surface receptors. Notably, all of these

  15. Baccatin III, a precursor for the semisynthesis of paclitaxel, inhibits the accumulation and suppressive activity of myeloid-derived suppressor cells in tumor-bearing mice.

    Science.gov (United States)

    Lee, Young-Hee; Lee, Young-Ran; Park, Chan-Su; Im, Sun-A; Song, Sukgil; Hong, Jin Tae; Whang, Bang Yeon; Kim, Kyungjae; Lee, Chong-Kil

    2014-08-01

    Myeloid-derived suppressor cells (MDSCs) mediate tumor-associated immune suppression in both cancer patients and tumor-bearing animals. Reduction or elimination of MDSCs reduces the rate of tumor progression and improves cancer therapies that employ mechanisms of immunity. Here we show that baccatin III, which is the precursor for the semisynthesis of paclitaxel, exerts anti-tumor immunomodulatory activity in very low doses (0.05-0.5mg/kg), although it is regarded as an inactive derivative of paclitaxel. Oral administration of baccatin III significantly reduced the growth of tumors induced by engrafting BALB/c mice with either 4 T1 mammary carcinoma or CT26 colon cancer cells. Baccatin III (0.5mg/kg) did not exert anti-tumor activity in athymic nude mice. Baccatin III decreased the accumulation of MDSCs in the spleens of the tumor-bearing mice. Furthermore, MDSCs isolated from baccatin III-treated mice, compared with those isolated from vehicle-treated mice, had a significantly reduced suppressive effect on T cells treated with the anti-CD3 and anti-CD28 monoclonal antibodies. Moreover, these cells produced significantly reduced amounts of reactive oxygen species and nitric oxide. These results suggest that baccatin III reduced tumor progression by inhibiting the accumulation and suppressive function of MDSCs. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Combining Oncolytic Virotherapy with p53 Tumor Suppressor Gene Therapy

    Directory of Open Access Journals (Sweden)

    Christian Bressy

    2017-06-01

    Full Text Available Oncolytic virus (OV therapy utilizes replication-competent viruses to kill cancer cells, leaving non-malignant cells unharmed. With the first U.S. Food and Drug Administration-approved OV, dozens of clinical trials ongoing, and an abundance of translational research in the field, OV therapy is poised to be one of the leading treatments for cancer. A number of recombinant OVs expressing a transgene for p53 (TP53 or another p53 family member (TP63 or TP73 were engineered with the goal of generating more potent OVs that function synergistically with host immunity and/or other therapies to reduce or eliminate tumor burden. Such transgenes have proven effective at improving OV therapies, and basic research has shown mechanisms of p53-mediated enhancement of OV therapy, provided optimized p53 transgenes, explored drug-OV combinational treatments, and challenged canonical roles for p53 in virus-host interactions and tumor suppression. This review summarizes studies combining p53 gene therapy with replication-competent OV therapy, reviews preclinical and clinical studies with replication-deficient gene therapy vectors expressing p53 transgene, examines how wild-type p53 and p53 modifications affect OV replication and anti-tumor effects of OV therapy, and explores future directions for rational design of OV therapy combined with p53 gene therapy.

  17. Combining Oncolytic Virotherapy with p53 Tumor Suppressor Gene Therapy.

    Science.gov (United States)

    Bressy, Christian; Hastie, Eric; Grdzelishvili, Valery Z

    2017-06-16

    Oncolytic virus (OV) therapy utilizes replication-competent viruses to kill cancer cells, leaving non-malignant cells unharmed. With the first U.S. Food and Drug Administration-approved OV, dozens of clinical trials ongoing, and an abundance of translational research in the field, OV therapy is poised to be one of the leading treatments for cancer. A number of recombinant OVs expressing a transgene for p53 (TP53) or another p53 family member (TP63 or TP73) were engineered with the goal of generating more potent OVs that function synergistically with host immunity and/or other therapies to reduce or eliminate tumor burden. Such transgenes have proven effective at improving OV therapies, and basic research has shown mechanisms of p53-mediated enhancement of OV therapy, provided optimized p53 transgenes, explored drug-OV combinational treatments, and challenged canonical roles for p53 in virus-host interactions and tumor suppression. This review summarizes studies combining p53 gene therapy with replication-competent OV therapy, reviews preclinical and clinical studies with replication-deficient gene therapy vectors expressing p53 transgene, examines how wild-type p53 and p53 modifications affect OV replication and anti-tumor effects of OV therapy, and explores future directions for rational design of OV therapy combined with p53 gene therapy.

  18. Tumor suppressor genes are frequently methylated in lymph node metastases of breast cancers

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    Xu Jia

    2010-07-01

    Full Text Available Abstract Introduction Metastasis represents a major adverse step in the progression of breast carcinoma. Lymph node invasion is the most relevant prognostic factor; however little is known on the molecular events associated with lymph node metastasis process. This study is to investigate the status and role of methylation in lymph node metastatic tumors. Materials and methods Bisulfite pyrosequencing is used to screen 6 putative tumor suppressor genes (HIN-1, RASSF1A, RIL, CDH13, RARβ2 and E-cadherin in 38 pairs of primary breast tumors and lymph node metastases. Results We found that HIN-1, CDH13, RIL, RASSF1A and RARβ2 were frequently methylated both in primary and metastatic tissues (range: 55.3%~89.5%. E-cadherin was not frequently methylated in either setting (range: 18.4%~23.7%. The methylation status of HIN-1, CDH13, RIL, and RARβ2 in lymph nodes metastasis were correlated with that in primary tumors. The Pearson correlation values ranged from 0.624 to 0.472 (p values HIN-1 methylation and hormone status in metastatic lymph nodes. Hypermethylation of HIN-1 in metastasis lymph nodes was significantly associated with expression of ER (odds ratio, 1.070; P = 0.024 and with PR (odds ratio, 1.046; P = 0.026. Conclusions This study suggests that hypermethylation of tumor suppressor genes is extended from primary to metastatic tumors during tumor progression.

  19. Transcriptional activation of the Lats1 tumor suppressor gene in tumors of CUX1 transgenic mice

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    Battat Robert

    2009-08-01

    Full Text Available Abstract Background Lats1 (large tumor suppressor 1 codes for a serine/threonine kinase that plays a role in the progression through mitosis. Genetic studies demonstrated that the loss of LATS1 in mouse, and of its ortholog wts (warts in Drosophila, is associated with increased cancer incidence. There are conflicting reports, however, as to whether overexpression of Lats1 inhibits cell proliferation. CUX1 is a transcription factor that exists in different isoforms as a result of proteolytic processing or alternative transcription initiation. Expression of p110 and p75 CUX1 in transgenic mice increases the susceptibility to cancer in various organs and tissues. In tissue culture, p110 CUX1 was shown to accelerate entry into S phase and stimulate cell proliferation. Results Genome-wide location arrays in cell lines of various cell types revealed that Lats1 was a transcriptional target of CUX1. Scanning ChIP analysis confirmed that CUX1 binds to the immediate promoter of Lats1. Expression of Lats1 was reduced in cux1-/- MEFs, whereas it was increased in cells stably or transiently expressing p110 or p75 CUX1. Reporter assays confirmed that the immediate promoter of Lats1 was sufficient to confer transcriptional activation by CUX1. Lats1 was found to be overexpressed in tumors from the mammary gland, uterus and spleen that arise in p110 or p75 CUX1 transgenic mice. In tissue culture, such elevated LATS1 expression did not hinder cell cycle progression in cells overexpressing p110 CUX1. Conclusion While inactivation of Lats1/wts in mouse and Drosophila can increase cancer incidence, results from the present study demonstrate that Lats1 is a transcriptional target of CUX1 that can be overexpressed in tumors of various tissue-types. Interestingly, two other studies documented the overexpression of LATS1 in human cervical cancers and basal-like breast cancers. We conclude that, similarly to other genes involved in mitotic checkpoint, cancer can be

  20. Functional association between Wwox tumor suppressor protein and p73, a p53 homolog

    Science.gov (United States)

    Aqeilan, Rami I.; Pekarsky, Yuri; Herrero, Juan J.; Palamarchuk, Alexey; Letofsky, Jean; Druck, Teresa; Trapasso, Francesco; Han, Shuang-Yin; Melino, Gerry; Huebner, Kay; Croce, Carlo M.

    2004-01-01

    The WWOX gene is a recently cloned tumor suppressor gene that spans the FRA16D fragile region. Wwox protein contains two WW domains that are generally known to mediate protein–protein interaction. Here we show that Wwox physically interacts via its first WW domain with the p53 homolog, p73. The tyrosine kinase, Src, phosphorylates Wwox at tyrosine 33 in the first WW domain and enhances its binding to p73. Our results further demonstrate that Wwox expression triggers redistribution of nuclear p73 to the cytoplasm and, hence, suppresses its transcriptional activity. In addition, we show that cytoplasmic p73 contributes to the proapoptotic activity of Wwox. Our findings reveal a functional cross-talk between p73 and Wwox tumor suppressor protein. PMID:15070730

  1. MicroRNA-34a is a potent tumor suppressor molecule in vivo in neuroblastoma.

    LENUS (Irish Health Repository)

    Tivnan, Amanda

    2011-01-01

    Neuroblastoma is a paediatric cancer which originates from precursor cells of the sympathetic nervous system and accounts for 15% of childhood cancer mortalities. With regards to the role of miRNAs in neuroblastoma, miR-34a, mapping to a chromosome 1p36 region that is commonly deleted, has been found to act as a tumor suppressor through targeting of numerous genes associated with cell proliferation and apoptosis.

  2. Ambient PM exposure and DNA methylation in tumor suppressor genes: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Cantone Laura

    2011-08-01

    Full Text Available Abstract Exposure to ambient air particles matter (PM has been associated with increased risk of lung cancer. Aberrant tumor suppressor gene promoter methylation has emerged as a promising biomarker for cancers, including lung cancer. Whether exposure to PM is associated with peripheral blood leukocyte (PBL DNA methylation in tumor suppressor genes has not been evaluated. In 63 male healthy steel workers with well-characterized exposure to metal-rich particles nearby Brescia, Italy, we evaluated whether exposure to PM and metal components was associated with PBL DNA methylation in 4 tumor suppressor genes (i.e., APC, p16, p53 and RASSF1A. Blood samples were obtained on the 1st (baseline and 4th day (post-exposure of the same work week and DNA methylation was measured using pyrosequencing. A linear mixed model was used to examine the correlations of the exposure with promoter methylation levels. Mean promoter DNA methylation levels of APC or p16 were significantly higher in post-exposure samples compared to that in baseline samples (p-values = 0.005 for APC, and p-value = 0.006 for p16. By contrast, the mean levels of p53 or RASSF1A promoter methylation was decreased in post-exposure samples compared to that in baseline samples (p-value = 0.015 for p53; and p-value 10 (β = 0.27, 95% CI: 0.13-0.40, and PM1 (β = 0.23, 95% CI: 0.09-0.38. In summary, ambient PM exposure was associated with PBL DNA methylation levels of tumor suppressor genes of APC, p16, p53 and RASSF1A, suggesting that such methylation alterations may reflect processes related to PM-induced lung carcinogenesis.

  3. ERF is a Potential ERK Modulated Tumor Suppressor in Prostate Cancer

    Science.gov (United States)

    2016-10-01

    fusion between the androgen- regulated upstream elements of the TMPRSS2- gene with the consequently upregulated ETS transcription factor ERG. Despite this...activates gene transcription. KEYWORDS prostate cancer, tumor suppressor, TMPRSS2-ERG 4 ACCOMPLISHMENTS Goals and Accomplishments I. Specific...negatively regulating ERG-dependent genes To investigate the possibility of competition between ERF and ERG, we used the ERG-positive VCaP cell line

  4. KLF10, transforming growth factor-{beta}-inducible early gene 1, acts as a tumor suppressor

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ki-Duk [Center for Agricultural Biomaterials, Seoul National University, Seoul 151-921 (Korea, Republic of); Laboratory of Protein Engineering and Comparative Immunology, School of Agricultural Biotechnology, Seoul National University, Seoul 151-921 (Korea, Republic of); Kim, Duk-Jung [The Institute of Hankook Life Science, 7-9 Myungryun-dong, Jongno-gu, Seoul 110-521 (Korea, Republic of); Lee, Jong Eun [Department of Anatomy, College of Medicine, Yonsei University, Seoul 120-752 (Korea, Republic of); Yun, Cheol-Heui [Center for Agricultural Biomaterials, Seoul National University, Seoul 151-921 (Korea, Republic of); Laboratory of Protein Engineering and Comparative Immunology, School of Agricultural Biotechnology, Seoul National University, Seoul 151-921 (Korea, Republic of); Lee, Woon Kyu, E-mail: wklee@inha.ac.kr [Laboratory of Developmental Genetics, School of Medicine, Inha University, Incheon 400-712 (Korea, Republic of); Brain Korea 21 Center for Advanced Medical Education, School of Medicine, Inha University, Incheon 400-712 (Korea, Republic of)

    2012-03-09

    Highlights: Black-Right-Pointing-Pointer KLF10{sup -/-} mice exhibited accelerated papilloma development after DMBA/TPA treatment. Black-Right-Pointing-Pointer KLF10{sup -/-} keratinocytes showed increased proliferation and apoptosis. Black-Right-Pointing-Pointer KLF10{sup -/-} MEFs yielded more colonies than wild-type one with H-Ras transfection. Black-Right-Pointing-Pointer KLF10 dose-dependently activated p21{sup WAF1/CIP1} transcription. Black-Right-Pointing-Pointer KLF10 is a tumor suppressor and that it targets p21{sup WAF1/CIP1} transcription. -- Abstract: Krueppel-like factor 10 (KLF10) has been suggested to be a putative tumor suppressor. In the present study, we generated KLF10 deficient mice to explore this hypothesis in vivo. KLF10 deficient mice exhibited increased predisposition to skin tumorigenesis and markedly accelerated papilloma development after DMBA/TPA treatment. On the other hand, KLF10 deficient keratinocytes showed increased proliferation and apoptosis. In colony formation assays after oncogenic H-Ras transfection, KLF10 deficient mouse embryonic fibroblasts (MEFs) yielded more colonies than wild-type MEFs. Furthermore, KLF10 dose-dependently activated p21{sup WAF1/CIP1} transcription, which was independent of p53 and Sp1 binding sites in p21{sup WAF1/CIP1} promoter. This study demonstrates that KLF10 is a tumor suppressor and that it targets p21{sup WAF1/CIP1} transcription.

  5. Amplification of Mdmx (or Mdm4) directly contributes to tumor formation by inhibiting p53 tumor suppressor activity

    DEFF Research Database (Denmark)

    Danovi, Davide; Meulmeester, Erik; Pasini, Diego

    2004-01-01

    Human tumors are believed to harbor a disabled p53 tumor suppressor pathway, either through direct mutation of the p53 gene or through aberrant expression of proteins acting in the p53 pathway, such as p14(ARF) or Mdm2. A role for Mdmx (or Mdm4) as a key negative regulator of p53 function in vivo...... has been established. However, a direct contribution of Mdmx to tumor formation remains to be demonstrated. Here we show that retrovirus-mediated Mdmx overexpression allows primary mouse embryonic fibroblast immortalization and leads to neoplastic transformation in combination with HRas(V12......). Furthermore, the human Mdmx ortholog, Hdmx, was found to be overexpressed in a significant percentage of various human tumors and amplified in 5% of primary breast tumors, all of which retained wild-type p53. Hdmx was also amplified and highly expressed in MCF-7, a breast cancer cell line harboring wild...

  6. Tumor induced hepatic myeloid derived suppressor cells can cause moderate liver damage.

    Directory of Open Access Journals (Sweden)

    Tobias Eggert

    Full Text Available Subcutaneous tumors induce the accumulation of myeloid derived suppressor cells (MDSC not only in blood and spleens, but also in livers of these animals. Unexpectedly, we observed a moderate increase in serum transaminases in mice with EL4 subcutaneous tumors, which prompted us to study the relationship of hepatic MDSC accumulation and liver injury. MDSC were the predominant immune cell population expanding in livers of all subcutaneous tumor models investigated (RIL175, B16, EL4, CT26 and BNL, while liver injury was only observed in EL4 and B16 tumor-bearing mice. Elimination of hepatic MDSC in EL4 tumor-bearing mice using low dose 5-fluorouracil (5-FU treatment reversed transaminase elevation and adoptive transfer of hepatic MDSC from B16 tumor-bearing mice caused transaminase elevation indicating a direct MDSC mediated effect. Surprisingly, hepatic MDSC from B16 tumor-bearing mice partially lost their damage-inducing potency when transferred into mice bearing non damage-inducing RIL175 tumors. Furthermore, MDSC expansion and MDSC-mediated liver injury further increased with growing tumor burden and was associated with different cytokines including GM-CSF, VEGF, interleukin-6, CCL2 and KC, depending on the tumor model used. In contrast to previous findings, which have implicated MDSC only in protection from T cell-mediated hepatitis, we show that tumor-induced hepatic MDSC themselves can cause moderate liver damage.

  7. The tumor suppressor gene Trp53 protects the mouse lens against posterior subcapsular cataracts and the BMP receptor Acvr1 acts as a tumor suppressor in the lens

    Directory of Open Access Journals (Sweden)

    Luke A. Wiley

    2011-07-01

    We previously found that lenses lacking the Acvr1 gene, which encodes a bone morphogenetic protein (BMP receptor, had abnormal proliferation and cell death in epithelial and cortical fiber cells. We tested whether the tumor suppressor protein p53 (encoded by Trp53 affected this phenotype. Acvr1 conditional knockout (Acvr1CKO mouse fiber cells had increased numbers of nuclei that stained for p53 phosphorylated on serine 15, an indicator of p53 stabilization and activation. Deletion of Trp53 rescued the Acvr1CKO cell death phenotype in embryos and reduced Acvr1-dependent apoptosis in postnatal lenses. However, deletion of Trp53 alone increased the number of fiber cells that failed to withdraw from the cell cycle. Trp53CKO and Acvr1;Trp53DCKO (double conditional knockout, but not Acvr1CKO, lenses developed abnormal collections of cells at the posterior of the lens that resembled posterior subcapsular cataracts. Cells from human posterior subcapsular cataracts had morphological and molecular characteristics similar to the cells at the posterior of mouse lenses lacking Trp53. In Trp53CKO lenses, cells in the posterior plaques did not proliferate but, in Acvr1;Trp53DCKO lenses, many cells in the posterior plaques continued to proliferate, eventually forming vascularized tumor-like masses at the posterior of the lens. We conclude that p53 protects the lens against posterior subcapsular cataract formation by suppressing the proliferation of fiber cells and promoting the death of any fiber cells that enter the cell cycle. Acvr1 acts as a tumor suppressor in the lens. Enhancing p53 function in the lens could contribute to the prevention of steroid- and radiation-induced posterior subcapsular cataracts.

  8. A tumor suppressor role of the Bub3 spindle checkpoint protein after apoptosis inhibition

    Science.gov (United States)

    Moutinho-Santos, Tatiana

    2013-01-01

    Most solid tumors contain aneuploid cells, indicating that the mitotic checkpoint is permissive to the proliferation of chromosomally aberrant cells. However, mutated or altered expression of mitotic checkpoint genes accounts for a minor proportion of human tumors. We describe a Drosophila melanogaster tumorigenesis model derived from knocking down spindle assembly checkpoint (SAC) genes and preventing apoptosis in wing imaginal discs. Bub3-deficient tumors that were also deficient in apoptosis displayed neoplastic growth, chromosomal aneuploidy, and high proliferative potential after transplantation into adult flies. Inducing aneuploidy by knocking down CENP-E and preventing apoptosis does not induce tumorigenesis, indicating that aneuploidy is not sufficient for hyperplasia. In this system, the aneuploidy caused by a deficient SAC is not driving tumorigenesis because preventing Bub3 from binding to the kinetochore does not cause hyperproliferation. Our data suggest that Bub3 has a nonkinetochore-dependent function that is consistent with its role as a tumor suppressor. PMID:23609535

  9. Characterization of the tumor suppressor gene WWOX in primary human oral squamous cell carcinomas

    Science.gov (United States)

    Pimenta, Flávio J.; Gomes, Dawidson A.; Perdigão, Paolla F.; Barbosa, Alvimar A.; Romano-Silva, Marco A.; Gomez, Marcus V.; Aldaz, C. Marcelo; De Marco, Luiz; Gomez, Ricardo S.

    2014-01-01

    Oral squamous cell carcinoma (OSCC) is the most common malignant neoplasm of the oral cavity, representing ~90% of all oral carcinomas and accounting for 3–5% of all malignancies. The WWOX gene (WW-domain containing oxidoreductase) is a candidate tumor suppressor gene located at 16q23.3–24.1, spanning the second most common fragile site, FRA16D. In this report, the role of the WWOX gene was investigated in 20 tumors and 10 normal oral mucosas, and we demonstrated an altered WWOX gene in 50% (10/20) of OSCCs. Using nested RT-PCR, mRNA transcription was altered in 35% of the tumors, with the complete absence of transcripts in 2 samples as well as absence of exons 6–8 (2 tumors), exon 7 (1 tumor), exon 7 and exon 6–8 (1 tumor) and partial loss of exons 8 and 9 (1 tumor). To determine if the aberrant transcripts were translated, Western blots were performed in all samples; however, only the normal protein was detected. By immunohistochemistry, a reduction in Wwox protein expression was observed, affecting 40% of the tumors when compared with normal mucosa. In addition, a novel somatic mutation (S329F) was found. The presence of alterations in mRNA transcription correlated with the reduced expression of Wwox protein in the tumors. These results show that the WWOX gene is frequently altered in OSCC and may contribute to the carcinogenesis processes in oral cancer. PMID:16152610

  10. Silencing of tumor suppressor genes RASSF1A, SLIT2, and WIF1 by promoter hypermethylation in hereditary breast cancer.

    Science.gov (United States)

    Alvarez, Carolina; Tapia, Teresa; Cornejo, Valeria; Fernandez, Wanda; Muñoz, Alex; Camus, Mauricio; Alvarez, Manuel; Devoto, Luigi; Carvallo, Pilar

    2013-06-01

    Promoter hypermethylation is gaining strength as one of the main mechanisms through which tumor suppressor genes are silenced during tumor progression. Three tumor suppressor genes are frequently found methylated in their promoter, in concordance with absence of expression, RASSF1A, SLIT2, and WIF1. In addition, a previous array-CGH analysis from our group showed that these genes are found in deleted genomic regions observed in hereditary breast cancer tumors. In the present work we analyzed the methylation status of these three tumor suppressor gene promoters in 47 hereditary breast cancer tumors. Promoter methylation status analysis of hereditary breast tumors revealed high methylation frequencies for the three genes (67% RASSF1A, 80% SLIT2, and 72% WIF1). Additionally, the presence of methylated PCR products was associated with absence of protein expression for the three genes and statistically significant for RASSF1A and WIF1. Interestingly, methylation of all the three genes was found in 4 out of 6 grade I invasive ductal carcinoma tumors. Association between RASSF1A methylation and DCIS tumors was found. These results suggest that silencing of these tumor suppressor genes is an early event in hereditary breast cancer, and could be a marker for pre-malignant phenotypes. Copyright © 2012 Wiley Periodicals, Inc.

  11. Simultaneous loss of the DLC1 and PTEN tumor suppressors enhances breast cancer cell migration

    Energy Technology Data Exchange (ETDEWEB)

    Heering, Johanna; Erlmann, Patrik [University of Stuttgart, Institute of Cell Biology and Immunology, Allmandring 31, 70569 Stuttgart (Germany); Olayioye, Monilola A., E-mail: monilola.olayioye@izi.uni-stuttgart.de [University of Stuttgart, Institute of Cell Biology and Immunology, Allmandring 31, 70569 Stuttgart (Germany)

    2009-09-10

    The phosphatase and tensin homolog (PTEN) gene is a tumor suppressor frequently deleted or mutated in sporadic tumors of the breast, prostate, endometrium and brain. The protein acts as a dual specificity phosphatase for lipids and proteins. PTEN loss confers a growth advantage to cells, protects from apoptosis and favors cell migration. The deleted in liver cancer 1 (DLC1) gene has emerged as a novel tumor suppressor downregulated in a variety of tumor types including those of the breast. DLC1 contains a Rho GTPase activating domain that is involved in the inhibition of cell proliferation, migration and invasion. To investigate how simultaneous loss of PTEN and DLC1 contributes to cell transformation, we downregulated both proteins by RNA interference in the non-invasive MCF7 breast carcinoma cell line. Joint depletion of PTEN and DLC1 resulted in enhanced cell migration in wounding and chemotactic transwell assays. Interestingly, both proteins were found to colocalize at the plasma membrane and interacted physically in biochemical pulldowns and coimmunoprecipitations. We therefore postulate that the concerted local inactivation of signaling pathways downstream of PTEN and DLC1, respectively, is required for the tight control of cell migration.

  12. The candidate tumor suppressor gene ECRG4 inhibits cancer cells migration and invasion in esophageal carcinoma

    Directory of Open Access Journals (Sweden)

    Lu ShihHsin

    2010-10-01

    Full Text Available Abstract Background The esophageal cancer related gene 4 (ECRG4 was initially identified and cloned in our laboratory from human normal esophageal epithelium (GenBank accession no.AF325503. ECRG4 was a new tumor suppressor gene in esophageal squamous cell carcinoma (ESCC associated with prognosis. In this study, we investigated the novel tumor-suppressing function of ECRG4 in cancer cell migration, invasion, adhesion and cell cycle regulation in ESCC. Methods Transwell and Boyden chamber experiments were utilized to examined the effects of ECRG4 expression on ESCC cells migration, invasion and adhesion. And flow cytometric analysis was used to observe the impact of ECRG4 expression on cell cycle regulation. Finally, the expression levels of cell cycle regulating proteins p53 and p21 in human ESCC cells transfected with ECRG4 gene were evaluated by Western blotting. Results The restoration of ECRG4 expression in ESCC cells inhibited cancer cells migration and invasion (P P > 0.05. Furthermore, ECRG4 could cause cell cycle G1 phase arrest in ESCC (P Conclusion ECRG4 is a candidate tumor suppressor gene which suppressed tumor cells migration and invasion without affecting cell adhesion ability in ESCC. Furthermore, ECRG4 might cause cell cycle G1 phase block possibly through inducing the increased expression of p53 and p21 proteins in ESCC.

  13. Mitochondria, calcium, and tumor suppressor Fus1: At the crossroad of cancer, inflammation, and autoimmunity.

    Science.gov (United States)

    Uzhachenko, Roman; Shanker, Anil; Yarbrough, Wendell G; Ivanova, Alla V

    2015-08-28

    Mitochondria present a unique set of key intracellular functions such as ATP synthesis, production of reactive oxygen species (ROS) and Ca2+ buffering. Mitochondria both encode and decode Ca2+ signals and these interrelated functions have a direct impact on cell signaling and metabolism. High proliferative potential is a key energy-demanding feature shared by cancer cells and activated T lymphocytes. Switch of a metabolic state mediated by alterations in mitochondrial homeostasis plays a fundamental role in maintenance of the proliferative state. Recent studies show that tumor suppressors have the ability to affect mitochondrial homeostasis controlling both cancer and autoimmunity. Herein, we discuss established and putative mechanisms of calcium-dependent regulation of both T cell and tumor cell activities. We use the mitochondrial protein Fus1 as a case of tumor suppressor that controls immune response and tumor growth via maintenance of mitochondrial homeostasis. We focus on the regulation of mitochondrial Ca2+ handling as a key function of Fus1 and highlight the mechanisms of a crosstalk between Ca2+ accumulation and mitochondrial homeostasis. Given the important role of Ca2+ signaling, mitochondrial Ca2+ transport and ROS production in the activation of NFAT and NF-κB transcription factors, we outline the importance of Fus1 activities in this context.

  14. The PTPN14 Tumor Suppressor Is a Degradation Target of Human Papillomavirus E7.

    Science.gov (United States)

    Szalmás, Anita; Tomaić, Vjekoslav; Basukala, Om; Massimi, Paola; Mittal, Suruchi; Kónya, József; Banks, Lawrence

    2017-04-01

    Activation of signaling pathways ensuring cell growth is essential for the proliferative competence of human papillomavirus (HPV)-infected cells. Tyrosine kinases and phosphatases are key regulators of cellular growth control pathways. A recently identified potential cellular target of HPV E7 is the cytoplasmic protein tyrosine phosphatase PTPN14, which is a potential tumor suppressor and is linked to the control of the Hippo and Wnt/beta-catenin signaling pathways. In this study, we show that the E7 proteins of both high-risk and low-risk mucosal HPV types can interact with PTPN14. This interaction is independent of retinoblastoma protein (pRb) and involves residues in the carboxy-terminal region of E7. We also show that high-risk E7 induces proteasome-mediated degradation of PTPN14 in cells derived from cervical tumors. This degradation appears to be independent of cullin-1 or cullin-2 but most likely involves the UBR4/p600 ubiquitin ligase. The degree to which E7 downregulates PTPN14 would suggest that this interaction is important for the viral life cycle and potentially also for the development of malignancy. In support of this we find that overexpression of PTPN14 decreases the ability of HPV-16 E7 to cooperate with activated EJ-ras in primary cell transformation assays.IMPORTANCE This study links HPV E7 to the deregulation of protein tyrosine phosphatase signaling pathways. PTPN14 is classified as a potential tumor suppressor protein, and here we show that it is very susceptible to HPV E7-induced proteasome-mediated degradation. Intriguingly, this appears to use a mechanism that is different from that employed by E7 to target pRb. Therefore, this study has important implications for our understanding of the molecular basis for E7 function and also sheds important light on the potential role of PTPN14 as a tumor suppressor. Copyright © 2017 American Society for Microbiology.

  15. Twist and miR-34a Are Involved in the Generation of Tumor-Educated Myeloid-Derived Suppressor Cells

    Directory of Open Access Journals (Sweden)

    Mingjuan Sun

    2013-10-01

    Full Text Available Tumors can induce the generation and accumulation of immunosuppressive cells such as myeloid-derived suppressor cells in the tumor microenvironment, contributing to tumor immunological escapes. Many studies have demonstrated that multiple factors could induce myeloid precursor cells into myeloid-derived suppressor cells, not dendritic cells. In our study, we found that tumor supernatants could induce the generation of myeloid-derived suppressor cells by disturbing the development of dendritic cells. Twist and miR-34a may regulate the effect of tumor cells inducing myeloid-derived suppressor cells via TGF-β and/or IL-10.

  16. Haploinsufficiency of the genes encoding the tumor suppressor Pten predisposes zebrafish to hemangiosarcoma

    Directory of Open Access Journals (Sweden)

    Suma Choorapoikayil

    2012-03-01

    PTEN is an essential tumor suppressor that antagonizes Akt/PKB signaling. The zebrafish genome encodes two Pten genes, ptena and ptenb. Here, we report that zebrafish mutants that retain a single wild-type copy of ptena or ptenb (ptena+/−ptenb−/− or ptena−/−ptenb+/− are viable and fertile. ptena+/−ptenb−/− fish develop tumors at a relatively high incidence (10.2% and most tumors developed close to the eye (26/30. Histopathologically, the tumor masses were associated with the retrobulbar vascular network and diagnosed as hemangiosarcomas. A single tumor was identified in 42 ptena−/−ptenb+/− fish and was also diagnosed as hemangiosarcoma. Immunohistochemistry indicated that the tumor cells in ptena+/−ptenb−/− and ptena−/−ptenb+/− fish proliferated rapidly and were of endothelial origin. Akt/PKB signaling was activated in the tumors, whereas Ptena was still detected in tumor tissue from ptena+/−ptenb−/− zebrafish. We conclude that haploinsufficiency of the genes encoding Pten predisposes to hemangiosarcoma in zebrafish.

  17. Haploinsufficiency of the genes encoding the tumor suppressor Pten predisposes zebrafish to hemangiosarcoma.

    Science.gov (United States)

    Choorapoikayil, Suma; Kuiper, Raoul V; de Bruin, Alain; den Hertog, Jeroen

    2012-03-01

    PTEN is an essential tumor suppressor that antagonizes Akt/PKB signaling. The zebrafish genome encodes two Pten genes, ptena and ptenb. Here, we report that zebrafish mutants that retain a single wild-type copy of ptena or ptenb (ptena(+/-)ptenb(-/-) or ptena(-/-)ptenb(+/-)) are viable and fertile. ptena(+/-)ptenb(-/-) fish develop tumors at a relatively high incidence (10.2%) and most tumors developed close to the eye (26/30). Histopathologically, the tumor masses were associated with the retrobulbar vascular network and diagnosed as hemangiosarcomas. A single tumor was identified in 42 ptena(-/-)ptenb(+/-) fish and was also diagnosed as hemangiosarcoma. Immunohistochemistry indicated that the tumor cells in ptena(+/-)ptenb(-/-) and ptena(-/-)ptenb(+/-) fish proliferated rapidly and were of endothelial origin. Akt/PKB signaling was activated in the tumors, whereas Ptena was still detected in tumor tissue from ptena(+/-)ptenb(-/-) zebrafish. We conclude that haploinsufficiency of the genes encoding Pten predisposes to hemangiosarcoma in zebrafish.

  18. A CRISPR/Cas9 Functional Screen Identifies Rare Tumor Suppressors.

    Science.gov (United States)

    Katigbak, Alexandra; Cencic, Regina; Robert, Francis; Sénécha, Patrick; Scuoppo, Claudio; Pelletier, Jerry

    2016-12-16

    An enormous amount of tumor sequencing data has been generated through large scale sequencing efforts. The functional consequences of the majority of mutations identified by such projects remain an open, unexplored question. This problem is particularly complicated in the case of rare mutations where frequency of occurrence alone or prediction of functional consequences are insufficient to distinguish driver from passenger or bystander mutations. We combine genome editing technology with a powerful mouse cancer model to uncover previously unsuspected rare oncogenic mutations in Burkitt's lymphoma. We identify two candidate tumor suppressors whose loss cooperate with MYC over-expression to accelerate lymphomagenesis. Our results highlight the utility of in vivo CRISPR/Cas9 screens combined with powerful mouse models to identify and validate rare oncogenic modifier events from tumor mutational data.

  19. ZBTB7A acts as a tumor suppressor through the transcriptional repression of glycolysis

    Science.gov (United States)

    Liu, Xue-Song; Haines, Jenna E.; Mehanna, Elie K.; Genet, Matthew D.; Ben-Sahra, Issam; Asara, John M.; Manning, Brendan D.

    2014-01-01

    Elevated glycolysis is a common metabolic trait of cancer, but what drives such metabolic reprogramming remains incompletely clear. We report here a novel transcriptional repressor-mediated negative regulation of glycolysis. ZBTB7A, a member of the POK (POZ/BTB and Krüppel) transcription repressor family, directly binds to the promoter and represses the transcription of critical glycolytic genes, including GLUT3, PFKP, and PKM. Analysis of The Cancer Genome Atlas (TCGA) data sets reveals that the ZBTB7A locus is frequently deleted in many human tumors. Significantly, reduced ZBTB7A expression correlates with up-regulation of the glycolytic genes and poor survival in colon cancer patients. Remarkably, while ZBTB7A-deficient tumors progress exceedingly fast, they exhibit an unusually heightened sensitivity to glycolysis inhibition. Our study uncovers a novel tumor suppressor role of ZBTB7A in directly suppressing glycolysis. PMID:25184678

  20. Paracrine Apoptotic Effect of p53 Mediated by Tumor Suppressor Par-4

    Directory of Open Access Journals (Sweden)

    Ravshan Burikhanov

    2014-01-01

    Full Text Available The guardian of the genome, p53, is often mutated in cancer and may contribute to therapeutic resistance. Given that p53 is intact and functional in normal tissues, we harnessed its potential to inhibit the growth of p53-deficient cancer cells. Specific activation of p53 in normal fibroblasts selectively induced apoptosis in p53-deficient cancer cells. This paracrine effect was mediated by p53-dependent secretion of the tumor suppressor Par-4. Accordingly, the activation of p53 in normal mice, but not p53−/− or Par-4−/− mice, caused systemic elevation of Par-4, which induced apoptosis of p53-deficient tumor cells. Mechanistically, p53 induced Par-4 secretion by suppressing the expression of its binding partner, UACA, which sequesters Par-4. Thus, normal cells can be empowered by p53 activation to induce Par-4 secretion for the inhibition of therapy-resistant tumors.

  1. A p53 Super-tumor Suppressor Reveals a Tumor Suppressive p53-Ptpn14-Yap Axis in Pancreatic Cancer.

    Science.gov (United States)

    Mello, Stephano S; Valente, Liz J; Raj, Nitin; Seoane, Jose A; Flowers, Brittany M; McClendon, Jacob; Bieging-Rolett, Kathryn T; Lee, Jonghyeob; Ivanochko, Danton; Kozak, Margaret M; Chang, Daniel T; Longacre, Teri A; Koong, Albert C; Arrowsmith, Cheryl H; Kim, Seung K; Vogel, Hannes; Wood, Laura D; Hruban, Ralph H; Curtis, Christina; Attardi, Laura D

    2017-10-09

    The p53 transcription factor is a critical barrier to pancreatic cancer progression. To unravel mechanisms of p53-mediated tumor suppression, which have remained elusive, we analyzed pancreatic cancer development in mice expressing p53 transcriptional activation domain (TAD) mutants. Surprisingly, the p5353,54 TAD2 mutant behaves as a "super-tumor suppressor," with an enhanced capacity to both suppress pancreatic cancer and transactivate select p53 target genes, including Ptpn14. Ptpn14 encodes a negative regulator of the Yap oncoprotein and is necessary and sufficient for pancreatic cancer suppression, like p53. We show that p53 deficiency promotes Yap signaling and that PTPN14 and TP53 mutations are mutually exclusive in human cancers. These studies uncover a p53-Ptpn14-Yap pathway that is integral to p53-mediated tumor suppression. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

  2. Tumor suppressor protein SMAR1 modulates the roughness of cell surface: combined AFM and SEM study

    Directory of Open Access Journals (Sweden)

    Mamgain Hitesh

    2009-10-01

    Full Text Available Abstract Background Imaging tools such as scanning electron microscope (SEM and atomic force microscope (AFM can be used to produce high-resolution topographic images of biomedical specimens and hence are well suited for imaging alterations in cell morphology. We have studied the correlation of SMAR1 expression with cell surface smoothness in cell lines as well as in different grades of human breast cancer and mouse tumor sections. Methods We validated knockdown and overexpression of SMAR1 using RT-PCR as well as Western blotting in human embryonic kidney (HEK 293, human breast cancer (MCF-7 and mouse melanoma (B16F1 cell lines. The samples were then processed for cell surface roughness studies using atomic force microscopy (AFM and scanning electron microscopy (SEM. The same samples were used for microarray analysis as well. Tumors sections from control and SMAR1 treated mice as well as tissues sections from different grades of human breast cancer on poly L-lysine coated slides were used for AFM and SEM studies. Results Tumor sections from mice injected with melanoma cells showed pronounced surface roughness. In contrast, tumor sections obtained from nude mice that were first injected with melanoma cells followed by repeated injections of SMAR1-P44 peptide, exhibited relatively smoother surface profile. Interestingly, human breast cancer tissue sections that showed reduced SMAR1 expression exhibited increased surface roughness compared to the adjacent normal breast tissue. Our AFM data establishes that treatment of cells with SMAR1-P44 results into increase in cytoskeletal volume that is supported by comparative gene expression data showing an increase in the expression of specific cytoskeletal proteins compared to the control cells. Altogether, these findings indicate that tumor suppressor function of SMAR1 might be exhibited through smoothening of cell surface by regulating expression of cell surface proteins. Conclusion Tumor suppressor

  3. Remodeling epigenetic modifications at tumor suppressor gene promoters with bovine oocyte extract.

    Science.gov (United States)

    Wang, Zhenfei; Yue, Yongli; Han, Pengyong; Sa, Rula; Ren, Xiaolv; Wang, Jie; Bai, Haidong; Yu, Haiquan

    2013-09-01

    Epigenetic silencing of tumor suppressor genes by aberrant DNA methylation and histone modifications at their promoter regions plays an important role in the initiation and progression of cancer. The therapeutic effect of the widely used epigenetic drugs, including DNA methyltransferase inhibitors and histone deacetylase inhibitors, remains unsatisfactory. One important underlying factor in the ineffectiveness of these drugs is that their actions lack specificity. To investigate whether oocyte extract can be used for epigenetic re-programming of cancer cells, H460 human lung cancer cells were reversibly permeabilized and incubated with bovine oocyte extract. Bisulfite sequencing showed that bovine oocyte extract induced significant demethylation at hypermethylated promoter CpG islands of the tumor suppressor genes RUNX3 and CDH1; however, the DNA methylation levels of repetitive sequences were not affected. Chromatin immunoprecipitation showed that bovine oocyte extract significantly reduced transcriptionally repressive histone modifications and increased transcriptionally activating histone modifications at the promoter regions of RUNX3 and CDH1. Bovine oocyte extract reactivated the expression of RUNX3 and CDH1 at both the messenger RNA and the protein levels without up-regulating the transcription of pluripotency-associated genes. At the functional level, anchorage-independent proliferation, migration and invasion of H460 cells was strongly inhibited. These results demonstrate that bovine oocyte extract reactivates epigenetically silenced tumor suppressor genes by remodeling the epigenetic modifications at their promoter regions. Bovine oocyte extract may provide a useful tool for investigating epigenetic mechanisms in cancer and a valuable source for developing novel safe therapeutic approaches that target epigenetic alterations. Copyright © 2013 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

  4. Neuron-Specific Deletion of the Nf2 Tumor Suppressor Impairs Functional Nerve Regeneration.

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    Alexander Schulz

    Full Text Available In contrast to axons of the central nervous system (CNS, axons of the peripheral nervous system (PNS show better, but still incomplete and often slow regeneration following injury. The tumor suppressor protein merlin, mutated in the hereditary tumor syndrome Neurofibromatosis type 2 (NF2, has recently been shown to have RhoA regulatory functions in PNS neurons-in addition to its well-characterized, growth-inhibitory activity in Schwann cells. Here we report that the conditional knockout of merlin in PNS neurons leads to impaired functional recovery of mice following sciatic nerve crush injury, in a gene-dosage dependent manner. Gross anatomical or electrophysiological alterations of sciatic nerves could not be detected. However, correlating with attenuated RhoA activation due to merlin deletion, ultrastructural analysis of nerve samples indicated enhanced sprouting of axons with reduced caliber size and increased myelination compared to wildtype animals. We conclude that deletion of the tumor suppressor merlin in the neuronal compartment of peripheral nerves results in compromised functional regeneration after injury. This mechanism could explain the clinical observation that NF2 patients suffer from higher incidences of slowly recovering facial nerve paralysis after vestibular schwannoma surgery.

  5. Microtubule-mediated transport of the tumor-suppressor protein Merlin and its mutants.

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    Benseñor, Lorena B; Barlan, Kari; Rice, Sarah E; Fehon, Richard G; Gelfand, Vladimir I

    2010-04-20

    The neurofibromatosis type 2 (NF2) tumor-suppressor protein Merlin is a member of the ERM family of proteins that links the cytoskeleton to the plasma membrane. In humans, mutations in the NF2 gene cause neurofibromatosis type-2 (NF2), a cancer syndrome characterized by the development of tumors of the nervous system. Previous reports have suggested that the subcellular distribution of Merlin is critical to its function, and that several NF2 mutants that lack tumor-suppressor activity present improper localization. Here we used a Drosophila cell culture model to study the distribution and mechanism of intracellular transport of Merlin and its mutants. We found that Drosophila Merlin formed cytoplasmic particles that move bidirectionally along microtubules. A single NF2-causing amino acid substitution in the FERM domain dramatically inhibited Merlin particle movement. Surprisingly, the presence of this immotile Merlin mutant also inhibited trafficking of the WT protein. Analysis of the movement of WT protein using RNAi and pull-downs showed that Merlin particles are associated with and moved by microtubule motors (kinesin-1 and cytoplasmic dynein), and that binding of motors and movement is regulated by Merlin phosphorylation. Inhibition of Merlin transport by expression of the dominant-negative mutant or depletion of kinesin-1 results in increased nuclear accumulation of the transcriptional coactivator Yorkie. These results demonstrate the requirement of microtubule-dependent transport for Merlin function.

  6. The conformation change and tumor suppressor role of Merlin are both independent of Serine 518 phosphorylation.

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    Xing, Wancai; Li, Meng; Zhang, Fayou; Ma, Xing; Long, Jiafu; Zhou, Hao

    2017-11-04

    Merlin functions as a tumor suppressor and suppresses malignant activity of cancer cells through multiple mechanisms. However, whether Serine 518 phosphorylation regulates the conformation of Merlin as well as the open-closed conformational changes affect Merlin's tumor inhibitory activity remain controversial. In this study, we used different mutants to mimic related conformational states of Merlin and investigated its physiological functions. Our results showed that the phosphorylation at Serine 518 has no influence on Merlin's conformation, subcellular localization, or cell proliferation inhibitory activity. As a fully closed conformational state, the A585W mutant loses the ability to recruit Lats2 to the cell membrane, but it does not affect its subcellular distribution or cell proliferation inhibitory activity. As a fully open conformational state, mimicking the conformation of Merlin isoform II, the ΔEL mutant has the same physiological function as the wild type Merlin isoform I. Collectively, we provide for the first time in vivo evidence that the function of Merlin, as a tumor suppressor is independent of its conformational change. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Merlin: the wizard requires protein stability to function as a tumor suppressor.

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    Morrow, K Adam; Shevde, Lalita A

    2012-12-01

    Neurofibromatosis type 2 (NF2), characterized by tumors of the nervous system, is a result of functional loss of the NF2 gene. The NF2 gene encodes Merlin (moesin-ezrin-radixin-like protein), an ERM (Ezrin, Radixin, Moesin) protein family member. Merlin functions as a tumor suppressor through impacting mechanisms related to proliferation, apoptosis, survival, motility, adhesion, and invasion. Several studies have summarized the tumor intrinsic mutations in Merlin. Given the fact that tumor cells are not in isolation, but rather in an intricate, mutually sustaining synergy with their surrounding stroma, the dialog between the tumor cells and the stroma can potentially impact the molecular homeostasis and promote evolution of the malignant phenotype. This review summarizes the epigenetic modifications, transcript stability, and post-translational modifications that impact Merlin. We have reviewed the role of extrinsic factors originating from the tumor milieu that influence the availability of Merlin inside the cell. Information regarding Merlin regulation could lead to novel therapeutics by stabilizing Merlin protein in tumors that have reduced Merlin protein expression without displaying any NF2 genetic alterations. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Point Mutations Effects on Charge Transport Properties of the Tumor-Suppressor Gene p53

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    Roemer, Rudolf A.; Shih, Chi-Tin; Roche, Stephan

    2008-03-01

    We report on a theoretical study of point mutations effects on charge transfer properties in the DNA sequence of the tumor-suppressor p53 gene. On the basis of effective tight-binding models which simulate hole propagation along the DNA, a statistical analysis of mutation-induced charge transfer modifications is performed. In contrast to non-cancerous mutations, mutation hotspots tend to result in significantly weaker changes of transmission properties. This suggests that charge transport could play a significant role for DNA-repairing deficiency yielding carcinogenesis.

  9. Epigenetically altered miR-1247 functions as a tumor suppressor in pancreatic cancer

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    Yi, Joo Mi; Kang, Eun-Jin; Kwon, Hyun-Mi; Bae, Jin-Han; Kang, Keunsoo; Ahuja, Nita; Yang, Kwangmo

    2017-01-01

    Altered expression of microRNAs has been strongly implicated in human cancers, and growing evidence is emerging that a number of miRNAs are downregulated in cancer associated with CpG island hypermethylation. Although pancreatic cancer is one of the most malignant human cancers, the roles of miRNAs underlying the tumorigenesis of pancreatic cancer are still poorly understood. In the present study, we explored the molecular functional role of microRNA-1247 as tumor suppressor associated with e...

  10. Computational Survey of FHIT, A Putative Human Tumor Suppressor, Truncates Structure

    OpenAIRE

    Eslamparast, Ameneh; Ghahremani, Mohammad Hossein; Sardari, Soroush

    2014-01-01

    Background Fragile Histidine Triad protein (FHIT), as a known tumor suppressor protein, has been proposed to play crucial role in inhibiting p53 degradation by MDM2. Studies have confirmed FHIT interaction with p53 or MDM2, although functional interacting domains of FHIT with MDM2 and/or p53 are not completely defined. Thus, through determining the significant structural interacting domains of FHIT, information with regard to MDM2 and p53 would be provided. As there were no previous studies e...

  11. Inhibitor of differentiation 4 (Id4 is a potential tumor suppressor in prostate cancer

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    Carey Jason PW

    2009-06-01

    Full Text Available Abstract Background Inhibitor of differentiation 4 (Id4, a member of the Id gene family is also a dominant negative regulator of basic helix loop helix (bHLH transcription factors. Some of the functions of Id4 appear to be unique as compared to its other family members Id1, Id2 and Id3. Loss of Id4 gene expression in many cancers in association with promoter hypermethylation has led to the proposal that Id4 may act as a tumor suppressor. In this study we provide functional evidence that Id4 indeed acts as a tumor suppressor and is part of a cancer associated epigenetic re-programming. Methods Data mining was used to demonstrate Id4 expression in prostate cancer. Methylation specific polymerase chain reaction (MSP analysis was performed to understand molecular mechanisms associated with Id4 expression in prostate cancer cell lines. The effect of ectopic Id4 expression in DU145 cells was determined by cell cycle analysis (3H thymidine incorporation and FACS, expression of androgen receptor, p53 and cyclin dependent kinase inhibitors p27 and p21 by a combination of RT-PCR, real time-PCR, western blot and immuno-cytochemical analysis. Results Id4 expression was down-regulated in prostate cancer. Id4 expression was also down-regulated in prostate cancer line DU145 due to promoter hyper-methylation. Ectopic Id4 expression in DU145 prostate cancer cell line led to increased apoptosis and decreased cell proliferation due in part by an S-phase arrest. In addition to S-phase arrest, ectopic Id4 expression in PC3 cells also resulted in prolonged G2/M phase. At the molecular level these changes were associated with increased androgen receptor (AR, p21, p27 and p53 expression in DU145 cells. Conclusion The results suggest that Id4 acts directly as a tumor suppressor by influencing a hierarchy of cellular processes at multiple levels that leads to a decreased cell proliferation and change in morphology that is possibly mediated through induction of previously

  12. Oncogenic RAS directs silencing of tumor suppressor genes through ordered recruitment of transcriptional repressors.

    Science.gov (United States)

    Wajapeyee, Narendra; Malonia, Sunil K; Palakurthy, Rajendra K; Green, Michael R

    2013-10-15

    We previously identified 28 cofactors through which a RAS oncoprotein directs transcriptional silencing of Fas and other tumor suppressor genes (TSGs). Here we performed RNAi-based epistasis experiments and found that RAS-directed silencing occurs through a highly ordered pathway that is initiated by binding of ZFP354B, a sequence-specific DNA-binding protein, and culminates in recruitment of the DNA methyltransferase DNMT1. RNAi and pharmacological inhibition experiments reveal that silencing requires continuous function of RAS and its cofactors and can be rapidly reversed, which may have therapeutic implications for reactivation of silenced TSGs in RAS-positive cancers.

  13. Amplexicaule A exerts anti-tumor effects by inducing apoptosis in human breast cancer.

    Science.gov (United States)

    Xiang, Meixian; Su, Hanwen; Shu, Guangwen; Wan, Dingrong; He, Feng; Loaec, Morgann; Ding, Yali; Li, Jun; Dovat, Sinisa; Yang, Gaungzhong; Song, Chunhua

    2016-04-05

    Chemotherapy is the main treatment for patients with breast cancer metastases, but natural alternatives have been receiving attention for their potential as novel anti-tumor reagents. Amplexicaule A (APA) is a flavonoid glucoside isolated from rhizomes of Polygonum amplexicaule D. Don var. sinense Forb (PADF). We found that APA has anti-tumor effects in a breast cancer xenograft mouse model and induces apoptosis in breast cancer cell lines. APA increased levels of cleaved caspase-3,-8,-9 and PARP, which resulted from suppression of MCL-1 and BCL-2 expression in the cells. APA also inactivated the Akt/mTOR pathway in breast cancer cells. Thus, APA exerts a strong anti-tumor effect on breast cancer cells, most likely through induction of apoptosis. Our study is the first to identify this novel anti-tumor compound and provides a new strategy for isolation and separation of single compounds from herbs.

  14. NDRG2 is a candidate tumor-suppressor for oral squamous-cell carcinoma

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    Furuta, Hiroshi; Kondo, Yuudai [Division of Oral and Maxillofacial Surgery, Medicine of Sensory and Motor Organs, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki-gun, Miyazaki 889-1692 (Japan); Division of Tumor and Cellular Biochemistry, Department of Medical Sciences, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki-gun, Miyazaki 889-1692 (Japan); Nakahata, Shingo; Hamasaki, Makoto [Division of Tumor and Cellular Biochemistry, Department of Medical Sciences, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki-gun, Miyazaki 889-1692 (Japan); Sakoda, Sumio [Division of Oral and Maxillofacial Surgery, Medicine of Sensory and Motor Organs, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki-gun, Miyazaki 889-1692 (Japan); Morishita, Kazuhiro, E-mail: kmorishi@med.miyazaki-u.ac.jp [Division of Tumor and Cellular Biochemistry, Department of Medical Sciences, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki-gun, Miyazaki 889-1692 (Japan)

    2010-01-22

    Oral cancer is one of the most common cancers worldwide, and squamous-cell carcinoma (OSCC) is the most common phenotype of oral cancer. Although patients with OSCC have poor survival rates and a high incidence of metastasis, the molecular mechanisms of OSCC development have not yet been elucidated. This study investigated whether N-myc downstream-regulated gene 2 (NDRG2) contributes to the carcinogenesis of OSCC, as NDRG2 is reported to be a candidate tumor-suppressor gene in a wide variety of cancers. The down-regulation of NDRG2 mRNA, which was dependent on promoter methylation, was seen in the majority of OSCC cases and in several cases of precancerous leukoplakia with dysplasia. Induction of NDRG2 expression in an HSC-3/OSCC cell line significantly inhibited cell proliferation and decreased colony formation ability on soft agar. The majority of OSCC cell lines showed an activation of PI3K/Akt signaling, and enforced expression of NDRG2 in HSC-3 cells decreased the level of phosphorylated Akt at Serine 473 (p-Akt). Immunohistochemical p-Akt staining was detected in 56.5% of the OSCC tumors, and 80.4% of the tumors were negative for NDRG2 staining. Moreover, positive p-Akt staining was inversely correlated with decreased NDRG2 expression in OSCC tumors with moderate to poor differentiation (p < 0.005). Therefore, NDRG2 is a candidate tumor-suppressor gene for OSCC development and probably contributes to the tumorigenesis of OSCC partly via the modulation of Akt signaling.

  15. Myeloid derived suppressor cells (MDSCs are increased and exert immunosuppressive activity together with polymorphonuclear leukocytes (PMNs in chronic myeloid leukemia patients.

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    Cesarina Giallongo

    Full Text Available Tumor immune tolerance can derive from the recruitment of suppressor cell population, including myeloid derived suppressor cells (MDSCs, able to inhibit T cells activity. We identified a significantly expanded MDSCs population in chronic myeloid leukemia (CML patients at diagnosis that decreased to normal levels after imatinib therapy. In addition, expression of arginase 1 (Arg1 that depletes microenvironment of arginine, an essential aminoacid for T cell function, resulted in an increase in patients at diagnosis. Purified CML CD11b+CD33+CD14-HLADR- cells markedly suppressed normal donor T cell proliferation in vitro. Comparing CML Gr-MDSCs to autologous polymorphonuclear leukocytes (PMNs we observed a higher Arg1 expression and activity in PMNs, together with an inhibitory effect on T cells in vitro. Our data indicate that CML cells create an immuno-tolerant environment associated to MDSCs expansion with immunosuppressive capacity mediated by Arg1. In addition, we demonstrated for the first time also an immunosuppressive activity of CML PMNs, suggesting a strong potential immune escape mechanism created by CML cells, which control the anti-tumor reactive T cells. MDSCs should be monitored in imatinib discontinuation trials to understand their importance in relapsing patients.

  16. Genomic loss of tumor suppressor miRNA-204 promotes cancer cell migration and invasion by activating AKT/mTOR/Rac1 signaling and actin reorganization.

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    J Saadi Imam

    Full Text Available Increasing evidence suggests that chromosomal regions containing microRNAs are functionally important in cancers. Here, we show that genomic loci encoding miR-204 are frequently lost in multiple cancers, including ovarian cancers, pediatric renal tumors, and breast cancers. MiR-204 shows drastically reduced expression in several cancers and acts as a potent tumor suppressor, inhibiting tumor metastasis in vivo when systemically delivered. We demonstrated that miR-204 exerts its function by targeting genes involved in tumorigenesis including brain-derived neurotrophic factor (BDNF, a neurotrophin family member which is known to promote tumor angiogenesis and invasiveness. Analysis of primary tumors shows that increased expression of BDNF or its receptor tropomyosin-related kinase B (TrkB parallel a markedly reduced expression of miR-204. Our results reveal that loss of miR-204 results in BDNF overexpression and subsequent activation of the small GTPase Rac1 and actin reorganization through the AKT/mTOR signaling pathway leading to cancer cell migration and invasion. These results suggest that microdeletion of genomic loci containing miR-204 is directly linked with the deregulation of key oncogenic pathways that provide crucial stimulus for tumor growth and metastasis. Our findings provide a strong rationale for manipulating miR-204 levels therapeutically to suppress tumor metastasis.

  17. Cancer-associated splicing variant of tumor suppressor AIMP2/p38: pathological implication in tumorigenesis.

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    Jin Woo Choi

    2011-03-01

    Full Text Available Although ARS-interacting multifunctional protein 2 (AIMP2, also named as MSC p38 was first found as a component for a macromolecular tRNA synthetase complex, it was recently discovered to dissociate from the complex and work as a potent tumor suppressor. Upon DNA damage, AIMP2 promotes apoptosis through the protective interaction with p53. However, it was not demonstrated whether AIMP2 was indeed pathologically linked to human cancer. In this work, we found that a splicing variant of AIMP2 lacking exon 2 (AIMP2-DX2 is highly expressed by alternative splicing in human lung cancer cells and patient's tissues. AIMP2-DX2 compromised pro-apoptotic activity of normal AIMP2 through the competitive binding to p53. The cells with higher level of AIMP2-DX2 showed higher propensity to form anchorage-independent colonies and increased resistance to cell death. Mice constitutively expressing this variant showed increased susceptibility to carcinogen-induced lung tumorigenesis. The expression ratio of AIMP2-DX2 to normal AIMP2 was increased according to lung cancer stage and showed a positive correlation with the survival of patients. Thus, this work identified an oncogenic splicing variant of a tumor suppressor, AIMP2/p38, and suggests its potential for anti-cancer target.

  18. NNK, a Tobacco-Specific Carcinogen, Inhibits the Expression of Lysyl Oxidase, a Tumor Suppressor

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    Guang Cheng

    2014-12-01

    Full Text Available A tobacco-specific carcinogen, 4-(methylnitrosamino-1-(3-pyridyl-1-butanone (NNK, is believed to contribute to the cancer burden in cigarette smokers. To evaluate NNK effects on the expression of lysyl oxidase (LOX, a tumor suppressor, we examined this enzyme at various levels in NNK-treated rat fetal lung fibroblasts (RFL6. Exposure of cells to NNK reduced levels of steady-states LOX mRNA and new transcript synthesis. NNK inhibited all LOX protein species in a dose-dependent manner. Although 300 µM NNK markedly decreased the level in the 46 kDa preproenzyme, under same conditions, there was no detectable amounts of the 50 kDa proenzyme and the 32 kDa mature enzyme suggesting NNK perturbing the LOX protein processing to its mature form. Moreover, NNK also suppressed LOX activities in conditioned media of treated cells. At the promoter level, NNK enhanced methylation of CpG, but decreased acetylation of histone H3 at the core promoter region of the LOX gene. These results indicated that transcriptional and translational processes of LOX are major targets for NNK. Thus, inactivation of tumor suppressor gene LOX may play a critical role in NNK carcinogenesis.

  19. Tumor Suppressor Genes within Common Fragile Sites Are Active Players in the DNA Damage Response.

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    Idit Hazan

    2016-12-01

    Full Text Available The role of common fragile sites (CFSs in cancer remains controversial. Two main views dominate the discussion: one suggests that CFS loci are hotspots of genomic instability leading to inactivation of genes encoded within them, while the other view proposes that CFSs are functional units and that loss of the encoded genes confers selective pressure, leading to cancer development. The latter view is supported by emerging evidence showing that expression of a given CFS is associated with genome integrity and that inactivation of CFS-resident tumor suppressor genes leads to dysregulation of the DNA damage response (DDR and increased genomic instability. These two viewpoints of CFS function are not mutually exclusive but rather coexist; when breaks at CFSs are not repaired accurately, this can lead to deletions by which cells acquire growth advantage because of loss of tumor suppressor activities. Here, we review recent advances linking some CFS gene products with the DDR, genomic instability, and carcinogenesis and discuss how their inactivation might represent a selective advantage for cancer cells.

  20. The tumor suppressor Rb and its related Rbl2 genes are regulated by Utx histone demethylase

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    Terashima, Minoru; Ishimura, Akihiko; Yoshida, Masakazu [Division of Functional Genomics, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Ishikawa (Japan); Suzuki, Yutaka; Sugano, Sumio [Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8561, Chiba (Japan); Suzuki, Takeshi, E-mail: suzuki-t@staff.kanazawa-u.ac.jp [Division of Functional Genomics, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Ishikawa (Japan)

    2010-08-20

    Research highlights: {yields} Utx increases expression of Rb and Rbl2 genes through its demethylase activity. {yields} Utx changes histone H3 methylation on the Rb and Rbl2 promoters. {yields} Utx induces decreased cell proliferation of mammalian primary cells. -- Abstract: Utx is a candidate tumor suppressor gene that encodes histone H3 lysine 27 (H3K27) demethylase. In this study, we found that ectopic expression of Utx enhanced the expression of retinoblastoma tumor suppressor gene Rb and its related gene Rbl2. This activation was dependent on the demethylase activity of Utx, and was suggested to contribute to the decreased cell proliferation induced by Utx. A chromatin immunoprecipitation assay showed that over-expressed Utx was associated with the promoter regions of Rb and Rbl2 resulting in the removal of repressive H3K27 tri-methylation and the increase in active H3K4 tri-methylation. Furthermore, siRNA-mediated knockdown of Utx revealed the recruitment of endogenous Utx protein on the promoters of Rb and Rbl2 genes. These results indicate that Rb and Rbl2 are downstream target genes of Utx and may play important roles in Utx-mediated cell growth control.

  1. Inhibition of pluripotency networks by the Rb tumor suppressor restricts reprogramming and tumorigenesis.

    Science.gov (United States)

    Kareta, Michael S; Gorges, Laura L; Hafeez, Sana; Benayoun, Bérénice A; Marro, Samuele; Zmoos, Anne-Flore; Cecchini, Matthew J; Spacek, Damek; Batista, Luis F Z; O'Brien, Megan; Ng, Yi-Han; Ang, Cheen Euong; Vaka, Dedeepya; Artandi, Steven E; Dick, Frederick A; Brunet, Anne; Sage, Julien; Wernig, Marius

    2015-01-08

    Mutations in the retinoblastoma tumor suppressor gene Rb are involved in many forms of human cancer. In this study, we investigated the early consequences of inactivating Rb in the context of cellular reprogramming. We found that Rb inactivation promotes the reprogramming of differentiated cells to a pluripotent state. Unexpectedly, this effect is cell cycle independent, and instead reflects direct binding of Rb to pluripotency genes, including Sox2 and Oct4, which leads to a repressed chromatin state. More broadly, this regulation of pluripotency networks and Sox2 in particular is critical for the initiation of tumors upon loss of Rb in mice. These studies therefore identify Rb as a global transcriptional repressor of pluripotency networks, providing a molecular basis for previous reports about its involvement in cell fate pliability, and implicate misregulation of pluripotency factors such as Sox2 in tumorigenesis related to loss of Rb function. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Tumor suppressor gene E-cadherin and its role in normal and malignant cells

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    Pećina-Šlaus Nives

    2003-10-01

    Full Text Available Abstract E-cadherin tumor suppressor genes are particularly active area of research in development and tumorigenesis. The calcium-dependent interactions among E-cadherin molecules are critical for the formation and maintenance of adherent junctions in areas of epithelial cell-cell contact. Loss of E-cadherin-mediated-adhesion characterises the transition from benign lesions to invasive, metastatic cancer. Nevertheless, there is evidence that E-cadherins may also play a role in the wnt signal transduction pathway, together with other key molecules involved in it, such as beta-catenins and adenomatous poliposis coli gene products. The structure and function of E-cadherin, gene and protein, in normal as well as in tumor cells are reviewed in this paper.

  3. A novel tumor suppressor function of glycine N-methyltransferase is independent of its catalytic activity but requires nuclear localization.

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    Suchandra DebRoy

    Full Text Available Glycine N-methyltransferase (GNMT, an abundant cytosolic enzyme, catalyzes the transfer of a methyl group from S-adenosylmethionine (SAM to glycine generating S-adenosylhomocysteine and sarcosine (N-methylglycine. This reaction is regulated by 5-methyltetrahydrofolate, which inhibits the enzyme catalysis. In the present study, we observed that GNMT is strongly down regulated in human cancers and is undetectable in cancer cell lines while the transient expression of the protein in cancer cells induces apoptosis and results in the activation of ERK1/2 as an early pro-survival response. The antiproliferative effect of GNMT can be partially reversed by treatment with the pan-caspase inhibitor zVAD-fmk but not by supplementation with high folate or SAM. GNMT exerts the suppressor effect primarily in cells originated from malignant tumors: transformed cell line of non-cancer origin, HEK293, was insensitive to GNMT. Of note, high levels of GNMT, detected in regenerating liver and in NIH3T3 mouse fibroblasts, do not produce cytotoxic effects. Importantly, GNMT, a predominantly cytoplasmic protein, was translocated into nuclei upon transfection of cancer cells. The presence of GNMT in the nuclei was also observed in normal human tissues by immunohistochemical staining. We further demonstrated that the induction of apoptosis is associated with the GNMT nuclear localization but is independent of its catalytic activity or folate binding. GNMT targeted to nuclei, through the fusion with nuclear localization signal, still exerts strong antiproliferative effects while its restriction to cytoplasm, through the fusion with nuclear export signal, prevents these effects (in each case the protein was excluded from cytosol or nuclei, respectively. Overall, our study indicates that GNMT has a secondary function, as a regulator of cellular proliferation, which is independent of its catalytic role.

  4. Genome-Wide CRISPR Screen Identifies Regulators of Mitogen-Activated Protein Kinase as Suppressors of Liver Tumors in Mice.

    Science.gov (United States)

    Song, Chun-Qing; Li, Yingxiang; Mou, Haiwei; Moore, Jill; Park, Angela; Pomyen, Yotsawat; Hough, Soren; Kennedy, Zachary; Fischer, Andrew; Yin, Hao; Anderson, Daniel G; Conte, Darryl; Zender, Lars; Wang, Xin Wei; Thorgeirsson, Snorri; Weng, Zhiping; Xue, Wen

    2017-04-01

    It has been a challenge to identify liver tumor suppressors or oncogenes due to the genetic heterogeneity of these tumors. We performed a genome-wide screen to identify suppressors of liver tumor formation in mice, using CRISPR-mediated genome editing. We performed a genome-wide CRISPR/Cas9-based knockout screen of P53-null mouse embryonic liver progenitor cells that overexpressed MYC. We infected p53(-/-);Myc;Cas9 hepatocytes with the mGeCKOa lentiviral library of 67,000 single-guide RNAs (sgRNAs), targeting 20,611 mouse genes, and transplanted the transduced cells subcutaneously into nude mice. Within 1 month, all the mice that received the sgRNA library developed subcutaneous tumors. We performed high-throughput sequencing of tumor DNA and identified sgRNAs increased at least 8-fold compared to the initial cell pool. To validate the top 10 candidate tumor suppressors from this screen, we collected data from patients with hepatocellular carcinoma (HCC) using the Cancer Genome Atlas and COSMIC databases. We used CRISPR to inactivate candidate tumor suppressor genes in p53(-/-);Myc;Cas9 cells and transplanted them subcutaneously into nude mice; tumor formation was monitored and tumors were analyzed by histology and immunohistochemistry. Mice with liver-specific disruption of p53 were given hydrodynamic tail-vein injections of plasmids encoding Myc and sgRNA/Cas9 designed to disrupt candidate tumor suppressors; growth of tumors and metastases was monitored. We compared gene expression profiles of liver cells with vs without tumor suppressor gene disrupted by sgRNA/Cas9. Genes found to be up-regulated after tumor suppressor loss were examined in liver cancer cell lines; their expression was knocked down using small hairpin RNAs, and tumor growth was examined in nude mice. Effects of the MEK inhibitors AZD6244, U0126, and trametinib, or the multi-kinase inhibitor sorafenib, were examined in human and mouse HCC cell lines. We identified 4 candidate liver tumor

  5. Loss of Tumor Suppressor Merlin in Advanced Breast Cancer Is due to Post-translational Regulation*

    Science.gov (United States)

    Morrow, K. Adam; Das, Shamik; Metge, Brandon J.; Ye, Keqiang; Mulekar, Madhuri S.; Tucker, J. Allan; Samant, Rajeev S.; Shevde, Lalita A.

    2011-01-01

    Unlike malignancies of the nervous system, there have been no mutations identified in Merlin in breast cancer. As such, the role of the tumor suppressor, Merlin, has not been investigated in breast cancer. We assessed Merlin expression in breast cancer tissues by immunohistochemistry and by real-time PCR. The expression of Merlin protein (assessed immunohistochemically) was significantly decreased in breast cancer tissues (although the transcript levels were comparable) simultaneous with increased expression of the tumor-promoting protein, osteopontin (OPN). We further demonstrate that the loss of Merlin in breast cancer is brought about, in part, due to OPN-initiated Akt-mediated phosphorylation of Merlin leading to its proteasomal degradation. Restoring expression of Merlin resulted in reduced malignant attributes of breast cancer, characterized by reduced invasion, migration, motility, and impeded tumor (xenograft) growth in immunocompromised mice. The possibility of developing a model using the relationship between OPN and Merlin was tested with a logistic regression model applied to immunohistochemistry data. This identified consistent loss of immunohistochemical expression of Merlin in breast tumor tissues. Thus, we demonstrate for the first time a role for Merlin in impeding breast malignancy, identify a novel mechanism for the loss of Merlin protein in breast cancer, and have developed a discriminatory model using Merlin and OPN expression in breast tumor tissues. PMID:21965655

  6. Loss of tumor suppressor Merlin in advanced breast cancer is due to post-translational regulation.

    Science.gov (United States)

    Morrow, K Adam; Das, Shamik; Metge, Brandon J; Ye, Keqiang; Mulekar, Madhuri S; Tucker, J Allan; Samant, Rajeev S; Shevde, Lalita A

    2011-11-18

    Unlike malignancies of the nervous system, there have been no mutations identified in Merlin in breast cancer. As such, the role of the tumor suppressor, Merlin, has not been investigated in breast cancer. We assessed Merlin expression in breast cancer tissues by immunohistochemistry and by real-time PCR. The expression of Merlin protein (assessed immunohistochemically) was significantly decreased in breast cancer tissues (although the transcript levels were comparable) simultaneous with increased expression of the tumor-promoting protein, osteopontin (OPN). We further demonstrate that the loss of Merlin in breast cancer is brought about, in part, due to OPN-initiated Akt-mediated phosphorylation of Merlin leading to its proteasomal degradation. Restoring expression of Merlin resulted in reduced malignant attributes of breast cancer, characterized by reduced invasion, migration, motility, and impeded tumor (xenograft) growth in immunocompromised mice. The possibility of developing a model using the relationship between OPN and Merlin was tested with a logistic regression model applied to immunohistochemistry data. This identified consistent loss of immunohistochemical expression of Merlin in breast tumor tissues. Thus, we demonstrate for the first time a role for Merlin in impeding breast malignancy, identify a novel mechanism for the loss of Merlin protein in breast cancer, and have developed a discriminatory model using Merlin and OPN expression in breast tumor tissues.

  7. Compositional features are potentially involved in the regulation of gene expression of tumor suppressor genes in human tissues.

    Science.gov (United States)

    Hajjari, Mohammadreza; Khoshnevisan, Atefeh; Behmanesh, Mehrdad

    2014-12-15

    Different mechanisms regulate the expression level of tissue specific genes in human. Here we report some compositional features such as codon usage bias, amino acid usage bias, codon frequency, and base composition which may be potentially related to mRNA amount of tissue specific tumor suppressor genes. Our findings support the possibility that structural elements in gene and protein may play an important role in the regulation of tumor suppressor genes, development, and tumorigenesis. The data presented here can open broad vistas in the understanding and treatment of a variety of human malignancies. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Circadian expression of clock- and tumor suppressor genes in human oral mucosa.

    Science.gov (United States)

    Zieker, Derek; Jenne, Isabel; Koenigsrainer, Ingmar; Zdichavsky, Marty; Nieselt, Kay; Buck, Katharina; Zieker, Judith; Beckert, Stefan; Glatzle, Joerg; Spanagel, Rainer; Koenigsrainer, Alfred; Northoff, Hinnak; Loeffler, Markus

    2010-01-01

    Circadian rhythms are daily oscillations of multiple biological processes driven by endogenous clocks. Imbalance of these rhythms has been associated with cancerogenesis in humans. To further elucidate the role circadian clocks have in cellular growth control, tumor suppression and cancer treatment, it is revealing to know how clock genes and clock-controlled genes are regulated in healthy humans. Therefore comparative microarray analyses were conducted investigating the relative mRNA expression of clock genes throughout a 24-hour period in cell samples obtained from oral mucosa of eight healthy diurnally active male study participants. Differentially expressed selected genes of interest were additionally evaluated using qRT-PCR. Microarray analysis revealed 33 significant differentially regulated clock genes and clock- controlled genes, throughout a one day period (6.00h, 12.00h, 18.00h, 24.00h). Hereof were 16 clock genes and 17 clock- controlled genes including tumor suppressor- and oncogenes. qRT-PCR of selected genes of interest, such as hPER2, hCRY1, hBMAL1, hCCRN4L and hSMAD5 revealed significant circadian regulations. Our study revealed a proper circadian regulation profile of several clock- and tumor suppressor genes at defined points in time in the participants studied. These findings could provide important information regarding genes displaying the same expression profile in the gastrointestinal tract amounting to a physiological expression profile of healthy humans. In the future asynchronous regulations of those genes might be an additional assistant method to detect derivations distinguishing normal from malignant tissue or assessing risk factors for cancer. Copyright 2010 S. Karger AG, Basel.

  9. Epigenetically altered miR-1247 functions as a tumor suppressor in pancreatic cancer.

    Science.gov (United States)

    Yi, Joo Mi; Kang, Eun-Jin; Kwon, Hyun-Mi; Bae, Jin-Han; Kang, Keunsoo; Ahuja, Nita; Yang, Kwangmo

    2017-04-18

    Altered expression of microRNAs has been strongly implicated in human cancers, and growing evidence is emerging that a number of miRNAs are downregulated in cancer associated with CpG island hypermethylation. Although pancreatic cancer is one of the most malignant human cancers, the roles of miRNAs underlying the tumorigenesis of pancreatic cancer are still poorly understood. In the present study, we explored the molecular functional role of microRNA-1247 as tumor suppressor associated with epigenetic alteration in pancreatic cancer. CpG islands methylation of miR-1247 is frequently observed in various pancreatic cancer cell lines and in primary pancreatic tumors, but not in normal pancreatic tissue. Ectopic expression of miR-1247 in five pancreatic cancer cell lines results in suppressing of cell growth, proliferation, migration, and invasion in vitro and tumorigenicity of pancreatic cancer cells in vivo. Interestingly, we found one putative target gene of miR-1247, regulator of chromosome condensation 2 (RCC2), harbored miR-1247 target sequences in the 3' UTR of its mRNA. In functional studies in vitro to understand the interaction between miR-1247 and RCC2, decreasing of RCC2 gene expression by miR-1247 was observed by immunoblotting and immunohistochemistry at both mRNA and protein levels. Moreover, luciferase reporter assay confirmed that RCC2 was a direct target of miR-1247. Taken together, our data suggest that CpG island hypermethylation of miR-1247 is responsible for its downregulation in pancreatic cancer, and ectopic expression of miR-1247 functions as a potential tumor suppressor targeting RCC2 in pancreatic cancer cells.

  10. Evidence that selenium binding protein 1 is a tumor suppressor in prostate cancer.

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    Emmanuel Ansong

    Full Text Available Selenium-Binding Protein 1 (SBP1, SELENBP1, hSP56 is a selenium-associated protein shown to be at lower levels in tumors, and its lower levels are frequently predictive of a poor clinical outcome. Distinguishing indolent from aggressive prostate cancer is a major challenge in disease management. Associations between SBP1 levels, tumor grade, and disease recurrence following prostatectomy were investigated by duplex immunofluorescence imaging using a tissue microarray containing tissue from 202 prostate cancer patients who experienced biochemical (PSA recurrence after prostatectomy and 202 matched control patients whose cancer did not recur. Samples were matched by age, ethnicity, pathological stage and Gleason grade, and images were quantified using the Vectra multispectral imaging system. Fluorescent labels were targeted for SBP1 and cytokeratins 8/18 to restrict scoring to tumor cells, and cell-by-cell quantification of SBP1 in the nucleus and cytoplasm was performed. Nuclear SBP1 levels and the nuclear to cytoplasm ratio were inversely associated with tumor grade using linear regression analysis. Following classification of samples into quartiles based on the SBP1 levels among controls, tumors in the lowest quartile were more than twice as likely to recur compared to those in any other quartile. Inducible ectopic SBP1 expression reduced the ability of HCT-116 human tumor cells to grow in soft agar, a measure of transformation, without affecting proliferation. Cells expressing SBP1 also demonstrated a robust induction in the phosphorylation of the p53 tumor suppressor at serine 15. These data indicate that loss of SBP1 may play an independent contributing role in prostate cancer progression and its levels might be useful in distinguishing indolent from aggressive disease.

  11. Myeloid-Derived Suppressor Cells in the Tumor Microenvironment: Current Knowledge and Future Perspectives.

    Science.gov (United States)

    Ibáñez-Vea, Maria; Zuazo, Miren; Gato, Maria; Arasanz, Hugo; Fernández-Hinojal, Gonzalo; Escors, David; Kochan, Grazyna

    2017-10-14

    The current knowledge on tumor-infiltrating myeloid-derived suppressor cells (MDSCs) is based mainly on the extensive work performed in murine models. Data obtained for human counterparts are generated on the basis of tumor analysis from patient samples. Both sources of information led to determination of the main suppressive mechanisms used by these cell subsets in tumor-bearing hosts. As a result of the identification of protein targets responsible for MDSCs suppressive activity, different therapeutics agents have been used to eliminate/reduce their adverse effect. In the present work, we review the current knowledge on suppressive mechanisms of MDSCs and therapeutic treatments that interfere with their differentiation, expansion or activity. Based on the accumulation of new evidences supporting their importance for tumor progression and metastasis, the interest in these cell types is increasing. We revise the methods of MDSC generation/differentiation ex vivo that may help in overcoming problems associated with limited numbers of cells available from animals and patients for their study.

  12. Transposon Mutagenesis Screen Identifies Potential Lung Cancer Drivers and CUL3 as a Tumor Suppressor

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    Dorr, Casey; Janik, Callie; Weg, Madison; Been, Raha A.; Bader, Justin; Kang, Ryan; Ng, Brandon; Foran, Lindsey; Landman, Sean R.; O’Sullivan, M. Gerard; Steinbach, Michael; Sarver, Aaron L.; Silverstein, Kevin A. T.; Largaespada, David A.

    2015-01-01

    Non-small cell lung cancers (NSCLCs) harbor thousands of passenger events that hide genetic drivers. Even highly recurrent events in NSCLC, such as mutations in PTEN, EGFR, KRAS, and ALK, are only detected in, at most, 30% of patients. Thus, many unidentified low-penetrant events are causing a significant portion of lung cancers. To detect low-penetrance drivers of NSCLC a forward genetic screen was performed in mice using the Sleeping Beauty (SB) DNA transposon as a random mutagen to generate lung tumors in a Pten deficient background. SB mutations coupled with Pten deficiency were sufficient to produce lung tumors in 29% of mice. Pten deficiency alone, without SB mutations, resulted in lung tumors in 11% of mice, while the rate in control mice was ~3%. In addition, thyroid cancer and other carcinomas as well as the presence of bronchiolar and alveolar epithelialization in mice deficient for Pten were also identified. Analysis of common transposon insertion sites identified 76 candidate cancer driver genes. These genes are frequently dysregulated in human lung cancers and implicate several signaling pathways. Cullin3 (Cul3), a member of an ubiquitin ligase complex that plays a role in the oxidative stress response pathway, was identified in the screen and evidence demonstrates that Cul3 functions as a tumor suppressor. PMID:25995385

  13. gld-1, a tumor suppressor gene required for oocyte development in Caenorhabditis elegans

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    Francis, R.; Schedl, T. [Washington Univ. School of Medicine, St. Louis, MO (United States); Barton, M.K.; Kimble, J. [Univ. of Wisconsin, Madison, WI (United States)

    1995-02-01

    We have characterized 31 mutations in the gld-1 (defective in germline development) gene of Caenorhabditis elegans. In gld-1 (null) hermaphrodites, oogenesis is abolished and a germline tumor forms where oocyte development would normally occur. By contrast, gld-1 (null) males are unaffected. The hermaphrodite germline tumor appears to derive from germ cells that enter the meiotic pathway normally but then exit pachytene and return to the mitotic cycle. Certain gld-1 partial loss-of-function mutations also abolish oogenesis, but germ cells arrest in pachytene rather than returning to mitosis. Our results indicate that gld-1 is a tumor suppressor gene required for oocyte development. The tumorous phenotype suggests that gld-1(+) may function to negatively regulate proliferation during meiotic prophase and/or act to direct progression through meiotic prophase. We also show that gld-1(+) has an additional nonessential role in germline sex determination: promotion of hermaphrodite spermatogenesis. This function of gld-1 is inferred from a haplo-insufficient phenotype and from the properties of gain-of-function gld-1 mutations that cause alterations in the sexual identity of germ cells. 69 refs., 10 figs., 8 tabs.

  14. Tumor suppressor p53 negatively regulates glycolysis stimulated by hypoxia through its target RRAD

    Science.gov (United States)

    Wu, Rui; Liang, Yingjian; Lin, Meihua; Liu, Jia; Chan, Chang S.; Hu, Wenwei; Feng, Zhaohui

    2014-01-01

    Cancer cells display enhanced glycolysis to meet their energetic and biosynthetic demands even under normal oxygen concentrations. Recent studies have revealed that tumor suppressor p53 represses glycolysis under normoxia as a novel mechanism for tumor suppression. As the common microenvironmental stress for tumors, hypoxia drives the metabolic switch from the oxidative phosphorylation to glycolysis, which is crucial for survival and proliferation of cancer cells under hypoxia. The p53's role and mechanism in regulating glycolysis under hypoxia is poorly understood. Here, we found that p53 represses hypoxia-stimulated glycolysis in cancer cells through RRAD, a newly-identified p53 target. RRAD expression is frequently decreased in lung cancer. Ectopic expression of RRAD greatly reduces glycolysis whereas knockdown of RRAD promotes glycolysis in lung cancer cells. Furthermore, RRAD represses glycolysis mainly through inhibition of GLUT1 translocation to the plasma membrane. Under hypoxic conditions, p53 induces RRAD, which in turn inhibits the translocation of GLUT1 and represses glycolysis in lung cancer cells. Blocking RRAD by siRNA greatly abolishes p53's function in repressing glycolysis under hypoxia. Taken together, our results revealed an important role and mechanism of p53 in antagonizing the stimulating effect of hypoxia on glycolysis, which contributes to p53's function in tumor suppression. PMID:25114038

  15. Oncogenic EGFR Represses the TET1 DNA Demethylase to Induce Silencing of Tumor Suppressors in Cancer Cells

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    Matteo Forloni

    2016-07-01

    Full Text Available Oncogene-induced DNA methylation-mediated transcriptional silencing of tumor suppressors frequently occurs in cancer, but the mechanism and functional role of this silencing in oncogenesis are not fully understood. Here, we show that oncogenic epidermal growth factor receptor (EGFR induces silencing of multiple unrelated tumor suppressors in lung adenocarcinomas and glioblastomas by inhibiting the DNA demethylase TET oncogene family member 1 (TET1 via the C/EBPα transcription factor. After oncogenic EGFR inhibition, TET1 binds to tumor suppressor promoters and induces their re-expression through active DNA demethylation. Ectopic expression of TET1 potently inhibits lung and glioblastoma tumor growth, and TET1 knockdown confers resistance to EGFR inhibitors in lung cancer cells. Lung cancer samples exhibited reduced TET1 expression or TET1 cytoplasmic localization in the majority of cases. Collectively, these results identify a conserved pathway of oncogenic EGFR-induced DNA methylation-mediated transcriptional silencing of tumor suppressors that may have therapeutic benefits for oncogenic EGFR-mediated lung cancers and glioblastomas.

  16. Identification of a third protein 4.1 tumor suppressor, protein 4.1R, in meningioma pathogenesis

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    Robb, Victoria A.; Li, Wen; Gascard, Philippe; Perry, Arie; Mohandas, Narla; Gutmann, David H.

    2003-06-11

    Meningiomas are common tumors of the central nervous system, however, the mechanisms under lying their pathogenesis are largely undefined. Two members of the Protein 4.1 super family, the neuro fibromatosis 2 (NF2) gene product (merlin/schwannomin) and Protein 4.1B have been implicated as meningioma tumor suppressors. In this report, we demonstrate that another Protein 4.1 family member, Protein 4.1R, also functions as a meningioma tumor suppressor. Based on the assignment of the Protein 4.1R gene to chromosome 1p32-36, a common region of deletion observed in meningiomas, we analyzed Protein 4.1R expression in meningioma cell lines and surgical tumor specimens. We observed loss of Protein 4.1R protein expression in two meningioma cell lines (IOMM-Lee, CH157-MN) by Western blotting as well as in 6 of 15 sporadic meningioma as by immuno histo chemistry (IHC). Analysis of a subset of these sporadic meningiomas by fluorescent in situ hybridization (FISH) with a Protein 4.1R specific probe demonstrated 100 percent concordance with the IHC results. In support of a meningioma tumor suppressor function, over expression of Protein 4.1R resulted in suppression of IOMM-Lee and CH157MN cell proliferation. Similar to the Protein 4.1B and merlin meningioma tumor suppressors, Protein 4.1R localization in the membrane fraction increased significantly under conditions of growth arrest in vitro. Lastly, Protein 4.1R interacted with some known merlin/Protein 4.1B interactors such as CD44 and bII-spectrin, but did not associate with the Protein 4.1B interactors 14-3-3 and PRMT3 or the merlin binding proteins SCHIP-1 and HRS. Collectively, these results suggest that Protein 4.1R functions as an important tumor suppressor important in the molecular pathogenesis of meningioma.

  17. Cdh11 acts as a tumor suppressor in a murine retinoblastoma model by facilitating tumor cell death.

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    Mellone N Marchong

    2010-04-01

    Full Text Available CDH11 gene copy number and expression are frequently lost in human retinoblastomas and in retinoblastomas arising in TAg-RB mice. To determine the effect of Cdh11 loss in tumorigenesis, we crossed Cdh11 null mice with TAg-RB mice. Loss of Cdh11 had no gross morphological effect on the developing retina of Cdh11 knockout mice, but led to larger retinal volumes in mice crossed with TAg-RB mice (p = 0.01. Mice null for Cdh11 presented with fewer TAg-positive cells at postnatal day 8 (PND8 (p = 0.01 and had fewer multifocal tumors at PND28 (p = 0.016, compared to mice with normal Cdh11 alleles. However, tumor growth was faster in Cdh11-null mice between PND8 and PND84 (p = 0.003. In tumors of Cdh11-null mice, cell death was decreased 5- to 10-fold (p<0.03 for all markers, while proliferation in vivo remained unaffected (p = 0.121. Activated caspase-3 was significantly decreased and beta-catenin expression increased in Cdh11 knockdown experiments in vitro. These data suggest that Cdh11 displays tumor suppressor properties in vivo and in vitro in murine retinoblastoma through promotion of cell death.

  18. The dioxin receptor has tumor suppressor activity in melanoma growth and metastasis.

    Science.gov (United States)

    Contador-Troca, María; Alvarez-Barrientos, Alberto; Barrasa, Eva; Rico-Leo, Eva M; Catalina-Fernández, Inmaculada; Menacho-Márquez, Mauricio; Bustelo, Xosé R; García-Borrón, José C; Gómez-Durán, Aurea; Sáenz-Santamaría, Javier; Fernández-Salguero, Pedro M

    2013-12-01

    Melanoma is a highly metastatic and malignant skin cancer having poor rates of patient survival. Since the incidence of melanoma is steadily increasing in the population, finding prognostic and therapeutic targets are crucial tasks in cancer. The dioxin receptor (AhR) is required for xenobiotic-induced toxicity and carcinogenesis and for cell physiology and organ homeostasis. Yet, the mechanisms by which AhR affects tumor growth and dissemination are largely uncharacterized. We report here that AhR contributes to the tumor-stroma interaction, blocking melanoma growth and metastasis when expressed in the tumor cell but supporting melanoma when expressed in the stroma. B16F10 cells engineered to lack AhR (small hairpin RNA for AhR) exacerbated melanoma primary tumorigenesis and lung metastasis when injected in AhR+/+ recipient mice but not when injected in AhR- /- mice or when co-injected with AhR-/- fibroblasts in an AhR+/+ stroma. Contrary, B16F10 cells expressing a constitutively active AhR had reduced tumorigenicity and invasiveness in either AhR genetic background. The tumor suppressor role of AhR in melanoma cells correlated with reduced migration and invasion, with lower numbers of cancer stem-like cells and with altered levels of β1-integrin and caveolin1. Human melanoma cell lines with highest AHR expression also had lowest migration and invasion. Moreover, AHR expression was reduced in human melanomas with respect to nevi lesions. We conclude that AhR knockdown in melanoma cells requires stromal AhR for maximal tumor progression and metastasis. Thus, AhR can be a molecular marker in melanoma and its activity in both tumor and stromal compartments should be considered.

  19. Nifuroxazide exerts potent anti-tumor and anti-metastasis activity in melanoma.

    Science.gov (United States)

    Zhu, Yongxia; Ye, Tinghong; Yu, Xi; Lei, Qian; Yang, Fangfang; Xia, Yong; Song, Xuejiao; Liu, Li; Deng, Hongxia; Gao, Tiantao; Peng, Cuiting; Zuo, Weiqiong; Xiong, Ying; Zhang, Lidan; Wang, Ningyu; Zhao, Lifeng; Xie, Yongmei; Yu, Luoting; Wei, Yuquan

    2016-02-02

    Melanoma is a highly malignant neoplasm of melanocytes with considerable metastatic potential and drug resistance, explaining the need for new candidates that inhibit tumor growth and metastasis. The signal transducer and activator of the transcription 3 (Stat3) signaling pathway plays an important role in melanoma and has been validated as promising anticancer target for melanoma therapy. In this study, nifuroxazide, an antidiarrheal agent identified as an inhibitor of Stat3, was evaluated for its anti-melanoma activity in vitro and in vivo. It had potent anti-proliferative activity against various melanoma cell lines and could induce G2/M phase arrest and cell apoptosis. Moreover, nifuroxazide markedly impaired melanoma cell migration and invasion by down-regulating phosphorylated-Src, phosphorylated-FAK, and expression of matrix metalloproteinase (MMP) -2, MMP-9 and vimentin. It also significantly inhibited tumor growth without obvious side effects in the A375-bearing mice model by inducing apoptosis and reducing cell proliferation and metastasis. Notably, nifuroxazide significantly inhibited pulmonary metastases, which might be associated with the decrease of myeloid-derived suppressor cells (MDSCs). These findings suggested that nifuroxazide might be a potential agent for inhibiting the growth and metastasis of melanoma.

  20. The tumor suppressor gene RBM5 inhibits lung adenocarcinoma cell growth and induces apoptosis

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    Shao Chen

    2012-08-01

    Full Text Available Abstract Background The loss of tumor suppressor gene (TSG function is a critical step in the pathogenesis of human lung cancer. RBM5 (RNA-binding motif protein 5, also named H37/LUCA-15 gene from chromosome 3p21.3 demonstrated tumor suppressor activity. However, the role of RBM5 played in the occurrence and development of lung cancer is still not well understood. Method Paired non-tumor and tumor tissues were obtained from 30 adenocarcinomas. The expression of RBM5 mRNA and protein was examined by RT-PCR and Western blot. A549 cell line was used to determine the apoptotic function of RBM5 in vitro. A549 cells were transiently transfected with pcDNA3.1-RBM5. AnnexinV analysis was performed by flow cytometry. Expression of Bcl-2, cleaved caspase-3, caspase-9 and PAPP proteins in A549 lung cancer cells and the A549 xenograft BALB/c nude mice model was determined by Western blot. Tumor suppressor activity of RBM5 was also examined in the A549 xenograft model treated with pcDNA3.1-RBM5 plasmid carried by attenuated Salmonella typhi Ty21a. Result The expression of RBM5 mRNA and protein was decreased significantly in adenocarcinoma tissues compared to that in the non-tumor tissues. In addition, as compared to the vector control, a significant growth inhibition of A549 lung cancer cells was observed when transfected with pcDNA3.1-RBM5 as determined by cell proliferation assay. We also found that overexpression of RBM5 induced both early and late apoptosis in A549 cells using AnnexinV/PI staining as determined by flow cytometry. Furthermore, the expression of Bcl-2 protein was decreased, whereas the expression of cleaved caspase-3, caspase-9 and PARP proteins was significantly increased in the RBM5 transfected cells; similarly, expression of decreased Bcl-2 and increased cleaved caspase-3 proteins was also examined in the A549 xenograft model. More importantly, we showed that accumulative and stable overexpression of RBM5 in the A549 xenograft BALB

  1. Large-Scale RNA Interference Screening to Identify Transcriptional Regulators of a Tumor Suppressor Gene.

    Science.gov (United States)

    Forloni, Matteo; Ho, Thuy; Sun, Lisha; Wajapeyee, Narendra

    2017-01-01

    RNA interference (RNAi) is a powerful research tool that can be used to silence the expression of a specific gene. In the past several years, RNAi has provided the opportunity to identify factors and pathways involved in complex biological processes by performing unbiased loss-of-function screens on a genome-wide scale. Here we describe a genome-wide RNAi screening strategy to identify factors that regulates epigenetic silencing of a specific tumor suppressor gene, using RASSF1A as an example. The approach we describe is a general RNAi screening strategy that can be applied to identify other factors that drive and/or maintain epigenetic modifications on specific genes, including cancer-related genes.

  2. RORα, a Potential Tumor Suppressor and Therapeutic Target of Breast Cancer

    Directory of Open Access Journals (Sweden)

    Jun Du

    2012-11-01

    Full Text Available The function of the nuclear receptor (NR in breast cancer progression has been investigated for decades. The majority of the nuclear receptors have well characterized natural ligands, but a few of them are orphan receptors for which no ligand has been identified. RORα, one member of the retinoid orphan nuclear receptor (ROR subfamily of orphan receptors, regulates various cellular and pathological activities. RORα is commonly down-regulated and/or hypoactivated in breast cancer compared to normal mammary tissue. Expression of RORα suppresses malignant phenotypes in breast cancer cells, in vitro and in vivo. Activity of RORα can be categorized into the canonical and non-canonical nuclear receptor pathways, which in turn regulate various breast cancer cellular function, including cell proliferation, apoptosis and invasion. This information suggests that RORα is a potent tumor suppressor and a potential therapeutic target for breast cancer.

  3. Oncogenes without a Neighboring Tumor-Suppressor Gene Are More Prone to Amplification.

    Science.gov (United States)

    Wu, William K K; Li, Xiangchun; Wang, Xiansong; Dai, Rudin Z W; Cheng, Alfred S L; Wang, Maggie H T; Kwong, Thomas; Chow, Tai C; Yu, Jun; Chan, Matthew T V; Wong, Sunny H

    2017-04-01

    Focal copy number gains or losses are important genomic hallmarks of cancer. The genomic distribution of oncogenes and tumor-suppressor genes (TSG) in relation to focal copy number aberrations is unclear. Our analysis revealed that the mean distance of TSGs from oncogenes was significantly shorter than that of noncancer genes, suggesting that oncogenes and TSGs tend to be in close physical proximity in the human genome. Such relationship was conserved in mouse and drosophila. Pan-cancer analysis using data from The Cancer Genome Atlas indicated that oncogenes without a nearby TSG are more prone to amplification. In conclusion, our study provides evidence for the nonrandom distribution of oncogenes and TSGs across different species. Our data also support that the existence of a neighboring TSG can suppress amplification of an oncogene, shedding new light on a previously unappreciated protective mechanism of TSGs. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  4. Methylation of HPV and a tumor suppressor gene reveals anal cancer and precursor lesions

    Science.gov (United States)

    Lorincz, Attila T.; Nathan, Mayura; Reuter, Caroline; Warman, Rhian; Thaha, Mohamed A.; Sheaff, Michael; Vasiljevic, Natasa; Ahmad, Amar; Cuzick, Jack; Sasieni, Peter

    2017-01-01

    We studied DNA methylation patterns of human papillomavirus (HPV) and tumor suppressor gene EPB41L3 in 148 anal and perianal biopsies to determine whether high levels of methylation would be associated with anal intraepithelial neoplasia (AIN). The most prevalent HPV type was HPV16, detected in 54% of the 30 benign biopsies, 33% of the 43 low-grade AIN (lgAIN), 82% of the 59 high grade AIN (hgAIN) and 4 of the 5 anal cancers. A methylation score was developed (0.561*HPV16me+0.439*EPB41L3) which had increasing values with severity of disease: the mean was 8.1% in benign, 13.2% in lgAIN, 22.3% in hgAIN and 49.3% in cancers (p anal disease. PMID:28881579

  5. Assessment of Promoter Methylation Identifies PTCH as a Putative Tumor-suppressor Gene in Human CLL.

    Science.gov (United States)

    Schmidt-Wolf, Ingo G H; Plass, Christoph; Byrd, John C; Frevel, Kathrin; Pietsch, Torsten; Waha, Andreas

    2016-09-01

    Chronic lymphocytic leukemia (CLL) is characterized by a clonal accumulation of neoplastic lymphocytes, indicating disruption of apoptosis. Differential methylation hybridization analysis was performed to identify novel target genes silenced by CpG island methylation in patients with CLL. Patched (PTCH), a tumor-suppressor gene, was found to be frequently methylated in CLL samples compared to samples derived from healthy individuals. De novo methylation of a CpG island region located upstream of PTCH exon 1 was confirmed by pyrosequencing in 17/37 (46%) of peripheral blood mononuclear cells of patients with CLL, but in none isolated from seven healthy individuals. No association was found between PTCH hypermethylation and currently used prognostic CLL factors. Our investigation suggests that epigenetic silencing of PTCH is a mechanism contributing to CLL tumorigenesis. Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  6. Generation and characterization of mice carrying a conditional allele of the Wwox tumor suppressor gene.

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    John H Ludes-Meyers

    2009-11-01

    Full Text Available WWOX, the gene that spans the second most common human chromosomal fragile site, FRA16D, is inactivated in multiple human cancers and behaves as a suppressor of tumor growth. Since we are interested in understanding WWOX function in both normal and cancer tissues we generated mice harboring a conditional Wwox allele by flanking Exon 1 of the Wwox gene with LoxP sites. Wwox knockout (KO mice were developed by breeding with transgenic mice carrying the Cre-recombinase gene under the control of the adenovirus EIIA promoter. We found that Wwox KO mice suffered from severe metabolic defect(s resulting in growth retardation and all mice died by 3 wk of age. All Wwox KO mice displayed significant hypocapnia suggesting a state of metabolic acidosis. This finding and the known high expression of Wwox in kidney tubules suggest a role for Wwox in acid/base balance. Importantly, Wwox KO mice displayed histopathological and hematological signs of impaired hematopoiesis, leukopenia, and splenic atrophy. Impaired hematopoiesis can also be a contributing factor to metabolic acidosis and death. Hypoglycemia and hypocalcemia was also observed affecting the KO mice. In addition, bone metabolic defects were evident in Wwox KO mice. Bones were smaller and thinner having reduced bone volume as a consequence of a defect in mineralization. No evidence of spontaneous neoplasia was observed in Wwox KO mice. We have generated a new mouse model to inactivate the Wwox tumor suppressor gene conditionally. This will greatly facilitate the functional analysis of Wwox in adult mice and will allow investigating neoplastic transformation in specific target tissues.

  7. Promoter hypermethylation of KLF4 inactivates its tumor suppressor function in cervical carcinogenesis.

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    Wen-Ting Yang

    Full Text Available OBJECTIVE: The KLF4 gene has been shown to be inactivated in cervical carcinogenesis as a tumor suppressor. However, the mechanism of KLF4 silencing in cervical carcinomas has not yet been identified. DNA methylation plays a key role in stable suppression of gene expression. METHODS: The methylation status of the KLF4 promoter CpG islands was analyzed by bisulfite sequencing (BSQ in tissues of normal cervix and cervical cancer. KLF4 gene expression was detected by RT-PCR, immunohistochemistry and western blot. KLF4 promoter methylation in cervical cancer cell line was determined by BSQ and methylation-specific polymerase chain reaction (MS-PCR. Cell proliferation ability was detected by cell growth curve and MTT assay. RESULTS: The methylated allele was found in 41.90% of 24 cervical cancer tissues but only in 11.11% of 11 normal cervix tissues (P<0.005. KLF4 mRNA levels were significantly reduced in cervical cancer tissues compared with normal cervix tissues (P<0.01 and KLF4 mRNA expression showed a significant negative correlation with the promoter hypermethylation (r = -0.486, P = 0.003. Cervical cancer cell lines also showed a significant negative correlation between KLF4 expression and hypermethylation. After treatment with the demethylating agent 5-Azacytidine (5-Aza, the expression of KLF4 in the cervical cancer cell lines at both mRNA and protein levels was drastically increased, the cell proliferation ability was inhibited and the chemosensitivity for cisplatin was significantly increased. CONCLUSION: KLF4 gene is inactivated by methylation-induced silencing mechanisms in a large subset of cervical carcinomas and KLF4 promoter hypermethylation inactivates the gene's function as a tumor suppressor in cervical carcinogenesis.

  8. Expression of arf tumor suppressor in spermatogonia facilitates meiotic progression in male germ cells.

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    Michelle L Churchman

    2011-07-01

    Full Text Available The mammalian Cdkn2a (Ink4a-Arf locus encodes two tumor suppressor proteins (p16(Ink4a and p19(Arf that respectively enforce the anti-proliferative functions of the retinoblastoma protein (Rb and the p53 transcription factor in response to oncogenic stress. Although p19(Arf is not normally detected in tissues of young adult mice, a notable exception occurs in the male germ line, where Arf is expressed in spermatogonia, but not in meiotic spermatocytes arising from them. Unlike other contexts in which the induction of Arf potently inhibits cell proliferation, expression of p19(Arf in spermatogonia does not interfere with mitotic cell division. Instead, inactivation of Arf triggers germ cell-autonomous, p53-dependent apoptosis of primary spermatocytes in late meiotic prophase, resulting in reduced sperm production. Arf deficiency also causes premature, elevated, and persistent accumulation of the phosphorylated histone variant H2AX, reduces numbers of chromosome-associated complexes of Rad51 and Dmc1 recombinases during meiotic prophase, and yields incompletely synapsed autosomes during pachynema. Inactivation of Ink4a increases the fraction of spermatogonia in S-phase and restores sperm numbers in Ink4a-Arf doubly deficient mice but does not abrogate γ-H2AX accumulation in spermatocytes or p53-dependent apoptosis resulting from Arf inactivation. Thus, as opposed to its canonical role as a tumor suppressor in inducing p53-dependent senescence or apoptosis, Arf expression in spermatogonia instead initiates a salutary feed-forward program that prevents p53-dependent apoptosis, contributing to the survival of meiotic male germ cells.

  9. PCR-RFLP to Detect Codon 248 Mutation in Exon 7 of "p53" Tumor Suppressor Gene

    Science.gov (United States)

    Ouyang, Liming; Ge, Chongtao; Wu, Haizhen; Li, Suxia; Zhang, Huizhan

    2009-01-01

    Individual genome DNA was extracted fast from oral swab and followed up with PCR specific for codon 248 of "p53" tumor suppressor gene. "Msp"I restriction mapping showed the G-C mutation in codon 248, which closely relates to cancer susceptibility. Students learn the concepts, detection techniques, and research significance of point mutations or…

  10. LARG at chromosome 11q23 has functional characteristics of a tumor suppressor in human breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Ong, Danny C.T.; Rudduck, Christina; Chin, Koei; Kuo, Wen-Lin; Lie, Daniel K.H.; Chua, Constance L.M.; Wong, Chow Yin; Hong, Ga Sze; Gray, Joe; Lee, Ann S.G.

    2008-05-06

    Deletion of 11q23-q24 is frequent in a diverse variety of malignancies, including breast and colorectal carcinoma, implicating the presence of a tumor suppressor gene at that chromosomal region. We show here that LARG, from 11q23, has functional characteristics of a tumor suppressor. We examined a 6-Mb region on 11q23 by high-resolution deletion mapping, utilizing both loss of heterozygosity (LOH) analysis and microarray comparative genomic hybridization (CGH). LARG (also called ARHGEF12), identified from the analyzed region, was underexpressed in 34% of primary breast carcinomas and 80% of breast cancer cell lines including the MCF-7 line. Multiplex ligation-dependent probe amplification on 30 primary breast cancers and six breast cancer cell lines showed that LARG had the highest frequency of deletion compared to the BCSC-1 and TSLC1 genes, two known candidate tumor suppressor genes from 11q. In vitro analysis of breast cancer cell lines that underexpress LARG showed that LARG could be reactivated by trichostatin A, a histone deacetylase inhibitor, but not by 5-Aza-2{prime}-deoxycytidine, a demethylating agent. Bisulfite sequencing and quantitative high-throughput analysis of DNA methylation confirmed the lack of CpG island methylation in LARG in breast cancer. Restoration of LARG expression in MCF-7 cells by stable transfection resulted in reduced proliferation and colony formation, suggesting that LARG has functional characteristics of a tumor suppressor gene.

  11. The LKB1 tumor suppressor differentially affects anchorage independent growth of HPV positive cervical cancer cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Mack, Hildegard I.D.; Munger, Karl, E-mail: kmunger@rics.bwh.harvard.edu

    2013-11-15

    Infection with high-risk human papillomaviruses is causally linked to cervical carcinogenesis. However, most lesions caused by high-risk HPV infections do not progress to cancer. Host cell mutations contribute to malignant progression but the molecular nature of such mutations is unknown. Based on a previous study that reported an association between liver kinase B1 (LKB1) tumor suppressor loss and poor outcome in cervical cancer, we sought to determine the molecular basis for this observation. LKB1-negative cervical and lung cancer cells were reconstituted with wild type or kinase defective LKB1 mutants and we examined the importance of LKB1 catalytic activity in known LKB1-regulated processes including inhibition of cell proliferation and elevated resistance to energy stress. Our studies revealed marked differences in the biological activities of two kinase defective LKB1 mutants in the various cell lines. Thus, our results suggest that LKB1 may be a cell-type specific tumor suppressor. - Highlights: • LKB1 is a tumor suppressor that is linked to Peutz-Jeghers syndrome. • Peutz-Jeghers syndrome patients have a high incidence of cervical cancer. • Cervical cancer is caused by HPV infections. • This study investigates LKB1 tumor suppressor activity in cervical cancer.

  12. Catalytic activity of matrix metalloproteinase-19 is essential for tumor suppressor and anti-angiogenic activities in nasopharyngeal carcinoma

    Czech Academy of Sciences Publication Activity Database

    Chan, K.C.; Ko, J.M.; Lung, H.L.; Sedláček, Radislav; Zhang, Z.F.; Luo, D.Z.; Feng, Z.B.; Chen, S.; Chen, H.; Chan, K.W.; Tsao, S.W.; Chua, D.T.; Zabarovsky, E.R.; Stanbridge, E.J.; Lung, M.L.

    2011-01-01

    Roč. 129, č. 8 (2011), s. 1826-1837 ISSN 0020-7136 Grant - others:Research Grants Council of the Hong Kong Special Administrative Region(CN) HKU661708M Institutional research plan: CEZ:AV0Z50520514 Keywords : MMP19 * nasopharyngeal carcinoma * tumor suppressor gene * angiogenesis Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.444, year: 2011

  13. Genetic analysis of Ikaros target genes and tumor suppressor function in BCR-ABL1+ pre–B ALL

    Science.gov (United States)

    Aghajanirefah, Ali; McLaughlin, Jami; Cheng, Donghui; Geng, Huimin; Eggesbø, Linn M.; Smale, Stephen T.; Müschen, Markus

    2017-01-01

    Inactivation of the tumor suppressor gene encoding the transcriptional regulator Ikaros (IKZF1) is a hallmark of BCR-ABL1+ precursor B cell acute lymphoblastic leukemia (pre–B ALL). However, the mechanisms by which Ikaros functions as a tumor suppressor in pre–B ALL remain poorly understood. Here, we analyzed a mouse model of BCR-ABL1+ pre–B ALL together with a new model of inducible expression of wild-type Ikaros in IKZF1 mutant human BCR-ABL1+ pre–B ALL. We performed integrated genome-wide chromatin and expression analyses and identified Ikaros target genes in mouse and human BCR-ABL1+ pre–B ALL, revealing novel conserved gene pathways associated with Ikaros tumor suppressor function. Notably, genetic depletion of different Ikaros targets, including CTNND1 and the early hematopoietic cell surface marker CD34, resulted in reduced leukemic growth. Our results suggest that Ikaros mediates tumor suppressor function by enforcing proper developmental stage–specific expression of multiple genes through chromatin compaction at its target genes. PMID:28190001

  14. Enhancement of the RAD51 Recombinase Activity by the Tumor Suppressor PALB2

    Energy Technology Data Exchange (ETDEWEB)

    Dray, Eloise; Etchin, Julia; Wiese, Claudia; Saro, Dorina; Williams, Gareth J.; Hammel, Michal; Yu, Xiong; Galkin, Vitold E.; Liu, Dongqing; Tsai, Miaw-Sheue; Sy, Shirley M-H.; Egelman, Edward; Chen, Junjie; Sung, Patrick; Schild, D.

    2010-08-24

    Homologous recombination mediated by the RAD51 recombinase helps eliminate chromosomal lesions, such as DNA double-stranded breaks induced by radiation or arising from injured DNA replication forks. The tumor suppressors BRCA2 and PALB2 act together to deliver RAD51 to chromosomal lesions to initiate repair. Here we document a new function of PALB2 in the enhancement of RAD51's ability to form the D-loop. We show that PALB2 binds DNA and physically interacts with RAD51. Importantly, while PALB2 alone stimulates D-loop formation, a cooperative effect is seen with RAD51AP1, an enhancer of RAD51. This stimulation stems from PALB2's ability to function with RAD51 and RAD51AP1 to assemble the synaptic complex. Our results help unveil a multi-faceted role of PALB2 in chromosome damage repair. Since PALB2 mutations can cause breast and other tumors or lead to Fanconi anemia, our findings are important for understanding the mechanism of tumor suppression in humans.

  15. Redox Regulation of the Tumor Suppressor PTEN by Hydrogen Peroxide and Tert-Butyl Hydroperoxide

    Directory of Open Access Journals (Sweden)

    Ying Zhang

    2017-05-01

    Full Text Available Organic peroxides and hydroperoxides are skin tumor promoters. Free radical derivatives from these compounds are presumed to be the prominent mediators of tumor promotion. However, the molecular targets of these species are unknown. Phosphatase and tensin homologs deleted on chromosome 10 (PTEN are tumor suppressors that play important roles in cell growth, proliferation, and cell survival by negative regulation of phosphoinositol-3-kinase/protein kinase B signaling. PTEN is reversibly oxidized in various cells by exogenous and endogenous hydrogen peroxide. Oxidized PTEN is converted back to the reduced form by cellular reducing agents, predominantly by the thioredoxin (Trx system. Here, the role of tert-butyl hydroperoxide (t-BHP in redox regulation of PTEN was analyzed by using cell-based and in vitro assays. Exposure to t-BHP led to oxidation of recombinant PTEN. In contrast to H2O2, PTEN oxidation by t-BHP was irreversible in HeLa cells. However, oxidized PTEN was reduced by exogenous Trx system. Taken together, these results indicate that t-BHP induces PTEN oxidation and inhibits Trx system, which results in irreversible PTEN oxidation in HeLa cells. Collectively, these results suggest a novel mechanism of t-BHP in the promotion of tumorigenesis.

  16. Multistep Phosphorylation by Oncogenic Kinases Enhances the Degradation of the NF2 Tumor Suppressor Merlin1

    Science.gov (United States)

    Laulajainen, Minja; Muranen, Taru; Nyman, Tuula A; Carpén, Olli; Grönholm, Mikaela

    2011-01-01

    Mutations in the Neurofibromatosis 2 gene (NF2) predispose to tumors of the nervous system, mainly schwannomas and meningiomas. The NF2 gene encodes for the tumor suppressor protein merlin (moesin-ezrin-radixin-like protein), which functions as a linker between the plasma membrane and the cytoskeleton. Carboxyterminal phosphorylation affects merlin activity, but many open questions on the regulation of merlin function still remain. The phosphoinositide 3-kinase/Akt pathway is activated in human vestibular schwannoma, suggesting a role for Akt-dependent merlin regulation in the formation of these tumors. In this study, we identify merlin serine 10 as a novel substrate for Akt phosphorylation. We demonstrate that this N-terminal phosphorylation directs merlin for proteasome-mediated degradation and affects merlin binding to the E3 ligase component DCAF1. Our data indicate that sequential phosphorylation of merlin C- and N-terminus by different oncogenic kinases targets merlin for degradation and thus downregulates its activity. On the basis of these findings, we propose a model for a posttranslational mechanism of merlin inactivation. PMID:21750658

  17. Multistep phosphorylation by oncogenic kinases enhances the degradation of the NF2 tumor suppressor merlin.

    Science.gov (United States)

    Laulajainen, Minja; Muranen, Taru; Nyman, Tuula A; Carpén, Olli; Grönholm, Mikaela

    2011-07-01

    Mutations in the Neurofibromatosis 2 gene (NF2) predispose to tumors of the nervous system, mainly schwannomas and meningiomas. The NF2 gene encodes for the tumor suppressor protein merlin (moesin-ezrin-radixin-like protein), which functions as a linker between the plasma membrane and the cytoskeleton. Carboxyterminal phosphorylation affects merlin activity, but many open questions on the regulation of merlin function still remain. The phosphoinositide 3-kinase/Akt pathway is activated in human vestibular schwannoma, suggesting a role for Akt-dependent merlin regulation in the formation of these tumors. In this study, we identify merlin serine 10 as a novel substrate for Akt phosphorylation. We demonstrate that this N-terminal phosphorylation directs merlin for proteasome-mediated degradation and affects merlin binding to the E3 ligase component DCAF1. Our data indicate that sequential phosphorylation of merlin C- and N-terminus by different oncogenic kinases targets merlin for degradation and thus downregulates its activity. On the basis of these findings, we propose a model for a posttranslational mechanism of merlin inactivation.

  18. Potential role of estrogen receptor beta as a tumor suppressor of epithelial ovarian cancer.

    Directory of Open Access Journals (Sweden)

    Carine Bossard

    Full Text Available Ovarian cancer is the gynecological cancer exhibiting the highest morbidity and improvement of treatments is still required. Previous studies have shown that Estrogen-receptor beta (ERβ levels decreased along with ovarian carcinogenesis. Here, we present evidence that reintroduction of ERβ in BG-1 epithelial ovarian cancer cells, which express ERα, leads in vitro to a decrease of basal and estradiol-promoted cell proliferation. ERβ reduced the frequency of cells in S phase and increased the one of cells in G2/M phase. At the molecular level, we found that ERβ downregulated total retinoblastoma (Rb, phosphorylated Rb and phospho-AKT cellular content as well as cyclins D1 and A2. In addition, ERβ had a direct effect on ERα, by strongly inhibiting its expression and activity, which could explain part of the anti-proliferative action of ERβ. By developing a novel preclinical model of ovarian cancer based on a luminescent orthotopic xenograft in athymic Nude mice, we further revealed that ERβ expression reduces tumor growth and the presence of tumor cells in sites of metastasis, hence resulting in improved survival of mice. Altogether, these findings unveil a potential tumor-suppressor role of ERβ in ovarian carcinogenesis, which could be of potential clinical relevance for the selection of the most appropriate treatment for patients.

  19. Prognostic value of tumor suppressors in osteosarcoma before and after neoadjuvant chemotherapy.

    Science.gov (United States)

    Robl, Bernhard; Pauli, Chantal; Botter, Sander Martijn; Bode-Lesniewska, Beata; Fuchs, Bruno

    2015-05-09

    Primary bone cancers are among the deadliest cancer types in adolescents, with osteosarcomas being the most prevalent form. Osteosarcomas are commonly treated with multi-drug neoadjuvant chemotherapy and therapy success as well as patient survival is affected by the presence of tumor suppressors. In order to assess the prognostic value of tumor-suppressive biomarkers, primary osteosarcoma tissues were analyzed prior to and after neoadjuvant chemotherapy. We constructed a tissue microarray from high grade osteosarcoma samples, consisting of 48 chemotherapy naïve biopsies (BXs) and 47 tumor resections (RXs) after neoadjuvant chemotherapy. We performed immunohistochemical stainings of P53, P16, maspin, PTEN, BMI1 and Ki67, characterized the subcellular localization and related staining outcome with chemotherapy response and overall survival. Binary logistic regression analysis was used to analyze chemotherapy response and Kaplan-Meier-analysis as well as the Cox proportional hazards model was applied for analysis of patient survival. No significant associations between biomarker expression in BXs and patient survival or chemotherapy response were detected. In univariate analysis, positive immunohistochemistry of P53 (P = 0.008) and P16 (P16; P = 0.033) in RXs was significantly associated with poor survival prognosis. In addition, presence of P16 in RXs was associated with poor survival in multivariate regression analysis (P = 0.003; HR = 0.067) while absence of P16 was associated with good chemotherapy response (P = 0.004; OR = 74.076). Presence of PTEN on tumor RXs was significantly associated with an improved survival prognosis (P = 0.022). Positive immunohistochemistry (IHC) of P16 and P53 in RXs was indicative for poor overall patient survival whereas positive IHC of PTEN was prognostic for good overall patient survival. In addition, we found that P16 might be a marker of osteosarcoma chemotherapy resistance. Therefore, our study supports the use of tumor RXs to

  20. Tumor suppressor miR-1 inhibits tumor growth and metastasis by simultaneously targeting multiple genes

    Science.gov (United States)

    Liu, Cuilian; Zhang, Song; Wang, Qizhi; Zhang, Xiaobo

    2017-01-01

    Cancer progression depends on tumor growth and metastasis, which are activated or suppressed by multiple genes. An individual microRNA may target multiple genes, suggesting that a miRNA may suppress tumor growth and metastasis via simultaneously targeting different genes. However, thus far, this issue has not been explored. In the present study, the findings showed that miR-1 could simultaneously inhibit tumor growth and metastasis of gastric and breast cancers by targeting multiple genes. The results indicated that miR-1 was significantly downregulated in cancer tissues compared with normal tissues. The miR-1 overexpression led to cell cycle arrest in the G1 phase in gastric and breast cancer cells but not in normal cells. Furthermore, the miR-1 overexpression significantly inhibited the metastasis of gastric and breast cancer cells. An analysis of the underlying mechanism revealed that the simultaneous inhibition of tumor growth and metastasis mediated by miR-1 was due to the synchronous targeting of 6 miR-1 target genes encoding cyclin dependent kinase 4, twinfilin actin binding protein 1, calponin 3, coronin 1C, WAS protein family member 2 and thymosin beta 4, X-linked. In vivo assays demonstrated that miR-1 efficiently inhibited tumor growth and metastasis of gastric and breast cancers in nude mice. Therefore, our study contributed novel insights into the miR-1′s roles in tumorigenesis of gastric and breast cancers. PMID:28159933

  1. Unfurling of the band 4.1, ezrin, radixin, moesin (FERM) domain of the merlin tumor suppressor.

    Science.gov (United States)

    Yogesha, S D; Sharff, Andrew J; Giovannini, Marco; Bricogne, Gerard; Izard, Tina

    2011-12-01

    The merlin-1 tumor suppressor is encoded by the Neurofibromatosis-2 (Nf2) gene and loss-of-function Nf2 mutations lead to nervous system tumors in man and to several tumor types in mice. Merlin is an ERM (ezrin, radixin, moesin) family cytoskeletal protein that interacts with other ERM proteins and with components of cell-cell adherens junctions (AJs). Merlin stabilizes the links of AJs to the actin cytoskeleton. Thus, its loss destabilizes AJs, promoting cell migration and invasion, which in Nf2(+/-) mice leads to highly metastatic tumors. Paradoxically, the "closed" conformation of merlin-1, where its N-terminal four-point-one, ezrin, radixin, moesin (FERM) domain binds to its C-terminal tail domain, directs its tumor suppressor functions. Here we report the crystal structure of the human merlin-1 head domain when crystallized in the presence of its tail domain. Remarkably, unlike other ERM head-tail interactions, this structure suggests that binding of the tail provokes dimerization and dynamic movement and unfurling of the F2 motif of the FERM domain. We conclude the "closed" tumor suppressor conformer of merlin-1 is in fact an "open" dimer whose functions are disabled by Nf2 mutations that disrupt this architecture. Copyright © 2011 The Protein Society.

  2. Unfurling of the band 4.1, ezrin, radixin, moesin (FERM) domain of the merlin tumor suppressor

    Energy Technology Data Exchange (ETDEWEB)

    Yogesha, S.D.; Sharff, Andrew J.; Giovannini, Marco; Bricogne, Gerard; Izard, Tina (House Ear); (Globel Phasing); (Scripps)

    2014-10-02

    The merlin-1 tumor suppressor is encoded by the Neurofibromatosis-2 (Nf2) gene and loss-of-function Nf2 mutations lead to nervous system tumors in man and to several tumor types in mice. Merlin is an ERM (ezrin, radixin, moesin) family cytoskeletal protein that interacts with other ERM proteins and with components of cell-cell adherens junctions (AJs). Merlin stabilizes the links of AJs to the actin cytoskeleton. Thus, its loss destabilizes AJs, promoting cell migration and invasion, which in Nf2{sup +/-} mice leads to highly metastatic tumors. Paradoxically, the 'closed' conformation of merlin-1, where its N-terminal four-point-one, ezrin, radixin, moesin (FERM) domain binds to its C-terminal tail domain, directs its tumor suppressor functions. Here we report the crystal structure of the human merlin-1 head domain when crystallized in the presence of its tail domain. Remarkably, unlike other ERM head-tail interactions, this structure suggests that binding of the tail provokes dimerization and dynamic movement and unfurling of the F2 motif of the FERM domain. We conclude the 'closed' tumor suppressor conformer of merlin-1 is in fact an 'open' dimer whose functions are disabled by Nf2 mutations that disrupt this architecture.

  3. Tumor-Derived Tissue Factor Aberrantly Activates Complement and Facilitates Lung Tumor Progression via Recruitment of Myeloid-Derived Suppressor Cells

    Directory of Open Access Journals (Sweden)

    Xiao Han

    2017-01-01

    Full Text Available The initiator of extrinsic coagulation, tissue factor (TF, and its non-coagulant isoform alternatively spliced TF (asTF are closely associated with tumor development. In the tumor microenvironment, the role of TF-induced coagulation in tumor progression remains to be fully elucidated. Using TF-knockdown lung tumor cells, we showed that TF is the dominant component of procoagulant activity but is dispensable in the cellular biology of tumor cells. In a xenograft model, using immunohistochemical analysis and flow cytometry analysis of the tumor microenvironment, we demonstrated that TF-induced fibrin deposition, which is correlated with complement activation and myeloid-derived suppressor cell (MDSC recruitment, is positively associated with tumor progression. C5aR antagonism blunted the effect of TF on tumor progression and decreased MDSC recruitment. In conclusion, our data suggested that in tumor microenvironment, TF-induced coagulation activated the complement system and subsequently recruited myeloid-derived suppressor cells to promote tumor growth, which brings new insights into the coagulation-induced complement activation within the tumor microenvironment during tumor progression.

  4. Antimicrobial peptaibols, novel suppressors of tumor cells, targeted calcium-mediated apoptosis and autophagy in human hepatocellular carcinoma cells

    Directory of Open Access Journals (Sweden)

    Chen Xiu-Lan

    2010-02-01

    Full Text Available Abstract Background Hepatocellular carcinoma (HCC is one of the most common cancers in the world which is highly chemoresistant to currently available chemotherapeutic agents. Thus, novel therapeutic targets are needed to be sought for the successful treatment of HCC. Peptaibols, a family of peptides synthesized non-ribosomally by the Trichoderma species and other fungi, exhibit antibiotic activities against bacteria and fungi. Few studies recently showed that peptaibols exerted cytotoxicity toward human lung epithelial and breast carcinoma cells. However, the mechanism involved in peptaibol-induced cell death remains poorly understood. Results Here, we showed that Trichokonin VI (TK VI, a peptaibol from Trichoderma pseudokoningii SMF2, induced growth inhibition of HCC cells in a dose-dependent manner. It did not obviously impair the viability of normal liver cells at lower concentration. Moreover, the suppression of cell viability resulted from the programmed cell death (PCD with characteristics of apoptosis and autophagy. An influx of Ca2+ triggered the activation of μ-calpain and proceeded to the translocation of Bax to mitochondria and subsequent promotion of apoptosis. On the other hand, typically morphological characteristics consistent with autophagy were also observed by punctate distribution of MDC staining and the induction of LC3-II, including extensive autophagic vacuolization and enclosure of cell organelles by these autophagosomes. More significantly, specific depletion of Bak expression by small RNA interfering (siRNA could partly attenuate TK VI-induced autophagy. However, siRNA against Bax led to increased autophagy. Conclusion Taken together, these findings showed for the first time that peptaibols were novel regulators involved in both apoptosis and autophagy, suggesting that the class of peptaibols might serve as potential suppressors of tumor cells.

  5. The Drosophila Netrin receptor frazzled/DCC functions as an invasive tumor suppressor

    Directory of Open Access Journals (Sweden)

    Duman-Scheel Molly

    2011-06-01

    Full Text Available Abstract Background Loss of heterozygosity at 18q, which includes the Deleted in Colorectal Cancer (DCC gene, has been linked to many human cancers. However, it is unclear if loss of DCC is the specific underlying cause of these cancers. The Drosophila imaginal discs are excellent systems in which to study DCC function, as it is possible to model human tumors through the generation of somatic clones of cells bearing multiple genetic lesions. Here, these attributes of the fly system were utilized to investigate the potential tumor suppressing functions of the Drosophila DCC homologue frazzled (fra during eye-antennal disc development. Results Most fra loss of function clones are eliminated during development. However, when mutant clone cells generated in the developing eye were rescued from death, partially differentiated eye cells were found outside of the normal eye field, and in extreme cases distant sites of the body. Characterization of these cells during development indicates that fra mutant cells display characteristics of invasive tumor cells, including increased levels of phospho-ERK, phospho-JNK, and Mmp-1, changes in cadherin expression, remodeling of the actin cytoskeleton, and loss of polarity. Mutation of fra promotes basement membrane degradation and invasion which are repressed by inhibition of Rho1 signaling. Although inhibition of JNK signaling blocks invasive phenotypes in some metastatic cancer models in flies, blocking JNK signaling inhibits fra mutant cell death, thereby enhancing the fra mutant phenotype. Conclusions The results of this investigation provide the first direct link between point mutations in fra/DCC and metastatic phenotypes in an animal model and suggest that Fra functions as an invasive tumor suppressor during Drosophila development.

  6. Alternative polyadenylation of tumor suppressor genes in small intestinal neuroendocrine tumors

    DEFF Research Database (Denmark)

    Rehfeld, Anders Aagaard; Plass, Mireya; Døssing, Kristina

    2014-01-01

    The tumorigenesis of small intestinal neuroendocrine tumors (SI-NETs) is poorly understood. Recent studies have associated alternative polyadenylation (APA) with proliferation, cell transformation, and cancer. Polyadenylation is the process in which the pre-messenger RNA is cleaved at a polyA site...... and a polyA tail is added. Genes with two or more polyA sites can undergo APA. This produces two or more distinct mRNA isoforms with different 3' untranslated regions. Additionally, APA can also produce mRNAs containing different 3'-terminal coding regions. Therefore, APA alters both the repertoire...... and the expression level of proteins. Here, we used high-throughput sequencing data to map polyA sites and characterize polyadenylation genome-wide in three SI-NETs and a reference sample. In the tumors, 16 genes showed significant changes of APA pattern, which lead to either the 3' truncation of mRNA coding regions...

  7. Methylation of tumor-suppressor genes in neuroblastoma: The RASSF1A gene is almost always methylated in primary tumors.

    Science.gov (United States)

    Michalowski, Mariana Bohns; de Fraipont, Florence; Plantaz, Dominique; Michelland, Sylvie; Combaret, Valérie; Favrot, Marie-Christine

    2008-01-01

    Currently, the best characterized genetic aberration in neuroblastoma (NB) is MYCN amplification, which has been clearly related to prognosis. In the present study, we investigated whether specific epigenetic alterations are associated with stage of disease. Sixty-two NBs (45 primary tumors and 17 NBs at relapse) were studied in terms of the methylation status of 19 genes (p15INK4a, p16INK4a, p14ARF, APC, RB1, RASSF1A, BLU, FHIT, RARbeta, INI1, TIMP3, NF2, MGMT, DAPK, FLIP, ECAD, CASP8, and the receptors DcR1 and DcR2). At diagnosis, we found hypermethylation of RASSF1A in 93% of these tumors, hypermethylation of TIMP3 in 51%, of CASP8 in 38%, of BLU in 34%, of DcR2 in 25%, and of DcR1 in 11%. All 17 tumors tested at relapse showed hypermethylation of RASSF1A (100%), while 10 showed hypermethylation of TIMP3 (59%), six of CASP8 (35%), five of DcR2 (29%), four of BLU (24%), and three of DcR1 (18%). Hypermethylation was related to clinical stage; NBs at stages 1, 2, and 4s were less frequently methylated than stages 3 and 4 disease (P = 0.002). These results from our series indicate that hypermethylation of tumor-suppressor genes may be important in the development and evolution of NB. These epigenetic alterations could be used as a marker of the disease and genes regulating methylation should be considered as possible therapeutic targets in NB. (c) 2007 Wiley-Liss, Inc.

  8. Genistein up-regulates tumor suppressor microRNA-574-3p in prostate cancer.

    Directory of Open Access Journals (Sweden)

    Takeshi Chiyomaru

    Full Text Available Genistein has been shown to inhibit cancers both in vitro and in vivo, by altering the expression of several microRNAs (miRNAs. In this study, we focused on tumor suppressor miRNAs regulated by genistein and investigated their function in prostate cancer (PCa and target pathways. Using miRNA microarray analysis and real-time RT-PCR we observed that miR-574-3p was significantly up-regulated in PCa cells treated with genistein compared with vehicle control. The expression of miR-574-3p was significantly lower in PCa cell lines and clinical PCa tissues compared with normal prostate cells (RWPE-1 and adjacent normal tissues. Low expression level of miR-574-3p was correlated with advanced tumor stage and higher Gleason score in PCa specimens. Re-expression of miR-574-3p in PCa cells significantly inhibited cell proliferation, migration and invasion in vitro and in vivo. miR-574-3p restoration induced apoptosis through reducing Bcl-xL and activating caspase-9 and caspase-3. Using GeneCodis software analysis, several pathways affected by miR-574-3p were identified, such as 'Pathways in cancer', 'Jak-STAT signaling pathway', and 'Wnt signaling pathway'. Luciferase reporter assays demonstrated that miR-574-3p directly binds to the 3' UTR of several target genes (such as RAC1, EGFR and EP300 that are components of 'Pathways in cancer'. Quantitative real-time PCR and Western analysis showed that the mRNA and protein expression levels of the three target genes in PCa cells were markedly down-regulated with miR-574-3p. Loss-of-function studies demonstrated that the three target genes significantly affect cell proliferation, migration and invasion in PCa cell lines. Our results show that genistein up-regulates tumor suppressor miR-574-3p expression targeting several cell signaling pathways. These findings enhance understanding of how genistein regulates with miRNA in PCa.

  9. TCP10L acts as a tumor suppressor by inhibiting cell proliferation in hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Zuo, Jie; Cai, Hao; Wu, Yanhua; Ma, Haijie; Jiang, Wei; Liu, Chao; Han, Dingding; Ji, Guoqing [State Key Laboratory of Genetic Engineering, Institute of Genetics, Fudan University, Shanghai 200433 (China); Yu, Long, E-mail: longyu@fudan.edu.cn [State Key Laboratory of Genetic Engineering, Institute of Genetics, Fudan University, Shanghai 200433 (China); Institutes of Biomedical Sciences, Fudan University, Shanghai 200032 (China)

    2014-03-28

    Highlights: • TCP10L was down-regulated in clinical hepatocellular carcinoma (HCC). • Expression of TCP10L correlated significantly with tumor size and Milan criteria. • Overexpression of TCP10L attenuated growth of HCC cells both in vitro and in vivo. • Knocking down TCP10L promoted cell proliferation and tumorigenesis of HCC cells. - Abstract: TCP10L (T-complex 10 (mouse)-like) has been identified as a liver and testis-specific gene. Although a potential transcriptional suppression function of TCP10L has been reported previously, biological function of this gene still remains largely elusive. In this study, we reported for the first time that TCP10L was significantly down-regulated in clinical hepatocellular carcinoma (HCC) samples when compared to the corresponding non-tumorous liver tissues. Furthermore, TCP10L expression was highly correlated with advanced cases exceeding the Milan criteria. Overexpression of TCP10L in HCC cells suppressed colony formation, inhibited cell cycle progression through G0/G1 phase, and attenuated cell growth in vivo. Consistently, silencing of TCP10L promoted cell cycle progression and cell growth. Therefore, our study has revealed a novel suppressor role of TCP10L in HCC, by inhibiting proliferation of HCC cells, which may facilitate the diagnosis and molecular therapy in HCC.

  10. Quantitative analysis of the tumor suppressor dendrogenin A using liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Noguer, Emmanuel; Soules, Régis; Netter, Claude; Nagarathinam, Citra; Leignadier, Julie; Huc-Claustre, Emilie; Serhan, Nizar; Rives, Arnaud; de Medina, Philippe; Silvente-Poirot, Sandrine; Poirot, Marc

    2017-10-01

    Dendrogenin A (DDA) was recently identified as a mammalian cholesterol metabolite that displays tumor suppressor and neurostimulating properties at low doses. In breast tumors, DDA levels were found to be decreased compared to normal tissues, evidencing a metabolic deregulation of DDA production in cancers. DDA is an amino-oxysterol that contains three protonatable nitrogen atoms. This makes it physico-chemically different from other oxysterols and it therefore requires specific analytical methods We have previously used a two-step method for the quantification of DDA in biological samples: 1) DDA purification from a Bligh and Dyer extract by RP-HPLC using a 250×4.6mm column, followed by 2) nano-electrospray ionization mass spectrometry (MS) fragmentation to analyze the HPLC fraction of interest. We report here the development a liquid chromatography tandem mass spectrometry method for the analysis of DDA and its analogues. This new method is fast (10min), resolving (peak width <4s) and has a weak carryover (<0.01%). We show that this technique efficiently separates DDA from its C17 isomer and other steroidal alkaloids from the same family establishing a proof of concept for the analysis of this family of amino-oxysterols. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Mitophagy Controls the Activities of Tumor Suppressor p53 to Regulate Hepatic Cancer Stem Cells.

    Science.gov (United States)

    Liu, Kai; Lee, Jiyoung; Kim, Ja Yeon; Wang, Linya; Tian, Yongjun; Chan, Stephanie T; Cho, Cecilia; Machida, Keigo; Chen, Dexi; Ou, Jing-Hsiung James

    2017-10-19

    Autophagy is required for benign hepatic tumors to progress into malignant hepatocellular carcinoma. However, the mechanism is unclear. Here, we report that mitophagy, the selective removal of mitochondria by autophagy, positively regulates hepatic cancer stem cells (CSCs) by suppressing the tumor suppressor p53. When mitophagy is enhanced, p53 co-localizes with mitochondria and is removed by a mitophagy-dependent manner. However, when mitophagy is inhibited, p53 is phosphorylated at serine-392 by PINK1, a kinase associated with mitophagy, on mitochondria and translocated into the nucleus, where it binds to the NANOG promoter to prevent OCT4 and SOX2 transcription factors from activating the expression of NANOG, a transcription factor critical for maintaining the stemness and the self-renewal ability of CSCs, resulting in the reduction of hepatic CSC populations. These results demonstrate that mitophagy controls the activities of p53 to maintain hepatic CSCs and provide an explanation as to why autophagy is required to promote hepatocarcinogenesis. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Surface Plasmon Resonance Sensing of Biorecognition Interactions within the Tumor Suppressor p53 Network.

    Science.gov (United States)

    Moscetti, Ilaria; Cannistraro, Salvatore; Bizzarri, Anna Rita

    2017-11-20

    Surface Plasmon Resonance (SPR) is a powerful technique to study the kinetics of biomolecules undergoing biorecognition processes, particularly suited for protein-protein interactions of biomedical interest. The potentiality of SPR was exploited to sense the interactions occurring within the network of the tumor suppressor p53, which is crucial for maintaining genome integrity and whose function is inactivated, mainly by down regulation or by mutation, in the majority of human tumors. This study includes p53 down-regulators, p53 mutants and also the p53 family members, p63 and p73, which could vicariate p53 protective function. Furthermore, the application of SPR was extended to sense the interaction of p53 with anti-cancer drugs, which might restore p53 function. An extended review of previous published work and unpublished kinetic data is provided, dealing with the interaction between the p53 family members, or their mutants and two anticancer molecules, Azurin and its cell-penetrating peptide, p28. All the kinetic results are discussed in connection with those obtained by a complementary approach operating at the single molecule level, namely Atomic Force Spectroscopy and the related literature data. The overview of the SPR kinetic results may significantly contribute to a deeper understanding of the interactions within p53 network, also in the perspective of designing suitable anticancer drugs.

  13. microRNA-184 functions as tumor suppressor in renal cell carcinoma.

    Science.gov (United States)

    Su, Zhengming; Chen, Duqun; Li, Yifan; Zhang, Enpu; Yu, Zuhu; Chen, Ting; Jiang, Zhimao; Ni, Liangchao; Yang, Shangqi; Gui, Yaoting; Ye, Jiongxian; Lai, Yongqing

    2015-03-01

    microRNAs (miRNAs) are evolutionarily conserved, endogenous, small, noncoding RNA molecules of approximately 22 nucleotides in length that function as post-transcriptional gene regulators. Their aberrant expression may be involved in human diseases, including cancer. Although miRNA-184 (miR-184) has been reported in other tumors, its function in renal cell carcinoma (RCC) is still unknown. The aim of the present study was to investigate the role of miR-184 in RCC. The impacts of miR-184 on cell migration, proliferation and apoptosis were evaluated using migration scratch, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry assay. Our studies revealed that miR-184 mimic significantly inhibits cell migration, suppresses cell proliferation and induces renal cancer cell apoptosis in vitro when compared with the negative control (P184 played a significant role as a tumor suppressor in RCC. Therefore, miR-184 may be a promising therapeutic target for renal cancer treatment in the future.

  14. Signalling pathways in UHRF1-dependent regulation of tumor suppressor genes in cancer

    Directory of Open Access Journals (Sweden)

    Mahmoud Alhosin

    2016-11-01

    Full Text Available Abstract Epigenetic silencing of tumor suppressor genes (TSGs through DNA methylation and histone changes is a main hallmark of cancer. Ubiquitin-like with PHD and RING Finger domains 1 (UHRF1 is a potent oncogene overexpressed in various solid and haematological tumors and its high expression levels are associated with decreased expression of several TSGs including p16 INK4A , BRCA1, PPARG and KiSS1. Using its several functional domains, UHRF1 creates a strong coordinated dialogue between DNA methylation and histone post-translation modification changes causing the epigenetic silencing of TSGs which allows cancer cells to escape apoptosis. To ensure the silencing of TSGs during cell division, UHRF1 recruits several enzymes including histone deacetylase 1 (HDAC1, DNA methyltransferase 1 (DNMT1 and histone lysine methyltransferases G9a and Suv39H1 to the right place at the right moment. Several in vitro and in vivo works have reported the direct implication of the epigenetic player UHRF1 in tumorigenesis through the repression of TSGs expression and suggested UHRF1 as a promising target for cancer treatment. This review describes the molecular mechanisms underlying UHRF1 regulation in cancer and discusses its importance as a therapeutic target to induce the reactivation of TSGs and subsequent apoptosis.

  15. miR-339-3p Is a Tumor Suppressor in Melanoma.

    Science.gov (United States)

    Weber, Claudia E M; Luo, Chonglin; Hotz-Wagenblatt, Agnes; Gardyan, Adriane; Kordaß, Theresa; Holland-Letz, Tim; Osen, Wolfram; Eichmüller, Stefan B

    2016-06-15

    Determinants of invasion and metastasis in cancer remain of great interest to define. Here, we report the definition of miR-339-3p as a novel tumor suppressive microRNA that blocks melanoma cell invasion without affecting cell survival. miR-339-3p was identified by a comprehensive functional screen of a human miRNA mimetic library in a cell-based assay for invasion by the melanoma cell line A375. miR-339-3p was determined as a strong inhibitor of invasion differentially expressed in melanoma cells and healthy melanocytes. MCL1 was defined as a target for downregulation by miR-339-3p, functioning through direct interaction with the 3' untranslated region of MCL1 mRNA. Blocking miR-339-3p by an antagomiR was sufficient to increase melanoma cell invasion, an effect that could be phenocopied by RNAi-mediated silencing of MCL1. In vivo studies established that miR-339-3p overexpression was sufficient to decrease lung colonization by A375 melanoma cells in NSG mice, relative to control cells. Overall, our results defined miR-339-3p as a melanoma tumor suppressor, the levels of which contributes to invasive aggressiveness. Cancer Res; 76(12); 3562-71. ©2016 AACR. ©2016 American Association for Cancer Research.

  16. 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.

  17. TIG3 tumor suppressor-dependent organelle redistribution and apoptosis in skin cancer cells.

    Directory of Open Access Journals (Sweden)

    Tiffany M Scharadin

    Full Text Available TIG3 is a tumor suppressor protein that limits keratinocyte survival during normal differentiation. It is also important in cancer, as TIG3 level is reduced in tumors and in skin cancer cell lines, suggesting that loss of expression may be required for cancer cell survival. An important goal is identifying how TIG3 limits cell survival. In the present study we show that TIG3 expression in epidermal squamous cell carcinoma SCC-13 cells reduces cell proliferation and promotes morphological and biochemical apoptosis. To identify the mechanism that drives these changes, we demonstrate that TIG3 localizes near the centrosome and that pericentrosomal accumulation of TIG3 alters microtubule and microfilament organization and organelle distribution. Organelle accumulation at the centrosome is a hallmark of apoptosis and we demonstrate that TIG3 promotes pericentrosomal organelle accumulation. These changes are associated with reduced cyclin D1, cyclin E and cyclin A, and increased p21 level. In addition, Bax level is increased and Bcl-XL level is reduced, and cleavage of procaspase 3, procaspase 9 and PARP is enhanced. We propose that pericentrosomal localization of TIG3 is a key event that results in microtubule and microfilament redistribution and pericentrosomal organelle clustering and that leads to cancer cell apoptosis.

  18. Surface Plasmon Resonance Sensing of Biorecognition Interactions within the Tumor Suppressor p53 Network

    Directory of Open Access Journals (Sweden)

    Ilaria Moscetti

    2017-11-01

    Full Text Available Surface Plasmon Resonance (SPR is a powerful technique to study the kinetics of biomolecules undergoing biorecognition processes, particularly suited for protein-protein interactions of biomedical interest. The potentiality of SPR was exploited to sense the interactions occurring within the network of the tumor suppressor p53, which is crucial for maintaining genome integrity and whose function is inactivated, mainly by down regulation or by mutation, in the majority of human tumors. This study includes p53 down-regulators, p53 mutants and also the p53 family members, p63 and p73, which could vicariate p53 protective function. Furthermore, the application of SPR was extended to sense the interaction of p53 with anti-cancer drugs, which might restore p53 function. An extended review of previous published work and unpublished kinetic data is provided, dealing with the interaction between the p53 family members, or their mutants and two anticancer molecules, Azurin and its cell-penetrating peptide, p28. All the kinetic results are discussed in connection with those obtained by a complementary approach operating at the single molecule level, namely Atomic Force Spectroscopy and the related literature data. The overview of the SPR kinetic results may significantly contribute to a deeper understanding of the interactions within p53 network, also in the perspective of designing suitable anticancer drugs.

  19. Hsf1 Is Required for the Nuclear Translocation of p53 Tumor Suppressor

    Directory of Open Access Journals (Sweden)

    Qiang Li

    2008-10-01

    Full Text Available Although the p53 tumor suppressor is most frequently inactivated by genetic mutations, exclusion from the nucleus is also seen in human tumors. We have begun to examine p53 nuclear importation by isolating a series of mutant cells in which the temperature-sensitive murine p53Val135 mutant is sequestered in the cytoplasm. We previously showed that that three of them (ALTR12, ALTR19, and ALTR25 constituted a single complementation group. Here, we found that ALTR12 cells are more sensitive to heat stress than either ALTR19 or ALTR25 and that there was a complete lack of induction of Hsp70 in response to heat shock. Western blot analysis showed no expression of the Hsf1 transcription factor, and neither heat shock nor azetidine could induce p53 nuclear localization in ALTR12 cells but did in parental A1–5 cells. Suppression of Hsf1 in A1–5 cells with quercetin or an Hsf1 siRNA reduced p53 nuclear importation and inhibited p53-mediated activation of a p21 reporter. Most convincingly, p53 nuclear importation could be restored in ALTR12 cells by introducing an exogenous Hsf1 gene. Collectively, our result suggests that Hsf1 is required for p53 nuclear importation and activation and implies that heat shock factors play a role in the regulation of p53.

  20. Effects of Tumor Suppressor Gene TCF21 on the Proliferation, Migration and Apoptosis of A549 Cells

    Directory of Open Access Journals (Sweden)

    Song HU

    2014-04-01

    Full Text Available Background and objective TCF21, a newly discovered gene, exhibits tumor suppressor function in a variety of tumors. This study aims to observe the effects of TCF21 on the proliferation, apoptosis and migration of A549 human lung adenocarcinoma epithelial cells. Methods TCF21 was overexpressed in A549 cells via lentiviral transfection. Fluorescence-based quantitative polymerase chain reaction and Western blot analysis were used to analyze the expression of the target gene. Transwell, proliferation assay, and flow cytometry were applied to detect the effect of TCF21 overexpression on the migration, proliferation, and apoptosis of A549 cells after transfection. Results The proliferation and migration of A549 cells were inhibited, and the apoptotic rate was increased by overexpressing TCF21. Conclusion The tumor suppressor gene, TCF21, significantly inhibits the proliferation and migration, as well as facilitates early apoptosis of A549 cells.

  1. [Hierarchical clustering analysis to detect associations between clinical and pathological features of gastric tumors and hypermethylation of suppressor genes].

    Science.gov (United States)

    Zavala G, Luis; Luengo J, Víctor; Ossandón C, Francisco; Riquelme S, Erick; Backhouse E, Claudia; Palma V, Mariana; Argandoña C, Jorge; Cumsille, Miguel Angel; Corvalán R, Alejandro

    2007-01-01

    Methylation is an inactivation mechanism for tumor suppressor genes, that can have important clinical implications. To analyze the methylation status of 11 tumor suppressor genes in pathological samples of diffuse gastric cancer. Eighty three patients with diffuse gastric cancer with information about survival and infection with Epstein Barr virus, were studied. DNA was extracted from pathological slides and the methylation status of genes p14, p15, p16, APC, p73, FHIT, E-cadherin, SEMA3B, BRCA-1, MINT-2 y MGMT, was studied using sodium bisulphite modification and polymerase chain reaction. Results were grouped according to the methylation index or Hierarchical clustering (TIGR MultiExperiment Viewer). Three genes had a high frequency of methylation (FHIT, BRCA1, APC), four had an intermediate frequency (p15, MGMT, p14, MINT2) and four had a low frequency (p16, p73, E-cadherin, SEMA3B). The methylation index had no association with clinical or pathological features of tumors or patients survival. Hierarchical clustering generated two clusters. One grouped clinical and pathological features with FHIT, BRCA1, and APC and the other grouped the other eight genes and Epstein Barr virus infection. Two significant associations were found, between APC and survival and p16/p14 and Epstein Barr virus infection. Hierarchical clustering is a tool that identifies associations between clinical and pathological features of tumors and methylation of tumor suppressor genes.

  2. Use of integrative epigenetic and cytogenetic analyses to identify novel tumor-suppressor genes in malignant melanoma.

    Science.gov (United States)

    Mithani, Suhail K; Smith, Ian M; Califano, Joseph A

    2011-08-01

    The objective of this study was to identify novel tumor-suppressor genes in melanoma, using an integrative genomic approach. Data from: (i) earlier reports of DNA loss and gain in malignant melanoma accompanied by comparative genomic hybridization high-definition array data of the entire human genome; (ii) microarray expression data from melanoma-derived cell lines identifying genes with significantly increased expression due to methylation using a pharmacologic demethylating strategy; and (iii) publicly available RNA expression microarray data of primary tumors and benign nevi were integrated using statistical tools to define a population of candidate tumor-suppressor genes. Twenty-seven genes were identified in areas of deletion that demonstrated diminished expression in primary melanomas relative to benign nevi and were significantly increased in expression by 5-Aza treatment. Seven genes of these 27 genes demonstrated methylation and deletion in a validation cohort of 14 separate primary tumors. These were: CHRDL1, SFRP1, TMEM47, LPL, RARRES1, PLCXD1, and KOX15. All of these genes demonstrated growth-suppressive properties with transfection into melanoma-derived cell lines. Seven putative tumor-suppressor genes in malignant melanoma were identified using a novel integrative technique.

  3. Epigenetic silencing of the tumor suppressor klotho in human breast cancer.

    Science.gov (United States)

    Rubinek, Tami; Shulman, Michal; Israeli, Shira; Bose, Shikha; Avraham, Ayelet; Zundelevich, Adi; Evron, Ella; Gal-Yam, Einav Nili; Kaufman, Bella; Wolf, Ido

    2012-06-01

    Klotho is a single pass transmembrane protein, associated with premature aging. We identified tumor suppressor activities for klotho, associated with reduced expression in breast cancer. We now aimed to analyze klotho expression in early stages of breast tumorigenesis and elucidate mechanisms leading to klotho silencing in breast tumors. We studied klotho expression, using immunohistochemistry, and found high klotho expression in all normal and mild hyperplasia samples, whereas reduced expression was associated with moderate and atypical ductal hyperplasia. Promoter methylation and histone deacetylation were studied as possible mechanisms for klotho silencing. Using bisulfite sequencing, and methylation-specific PCR, we identified KLOTHO promoter methylation in five breast cancer cell lines and in hyperplastic MCF-12A cells, but not in the non-tumorous mammary cell line HB2. Importantly, methylation status inversely correlated with klotho mRNA levels, and treatment of breast caner cells with 5-aza-2-deoxycytidine elevated klotho expression by up to 150-fold. KLOTHO promoter methylation was detected in 8/23 of breast cancer samples but not in normal breast samples. Chromatin immunoprecipitation revealed that in HB2 KLOTHO promoter was enriched with AcH3K9; however, in breast cancer cells, H3K9 was deacetylated, and treatment with the histone deacetylase inhibitor suberoylanilide bishydroxamide (SAHA) restored H3K9 acetylation. Taken together, these data indicate loss of klotho expression as an early event in breast cancer development, and suggest a role for DNA methylation and histone deacetylation in klotho silencing. Klotho expression and methylation may, therefore, serve as early markers for breast tumorigenesis.

  4. Tumor Suppressor p53 Stimulates the Expression of Epstein-Barr Virus Latent Membrane Protein 1.

    Science.gov (United States)

    Wang, Qianli; Lingel, Amy; Geiser, Vicki; Kwapnoski, Zachary; Zhang, Luwen

    2017-10-15

    Epstein-Barr virus (EBV) is associated with multiple human malignancies. EBV latent membrane protein 1 (LMP1) is required for the efficient transformation of primary B lymphocytes in vitro and possibly in vivo The tumor suppressor p53 plays a seminal role in cancer development. In some EBV-associated cancers, p53 tends to be wild type and overly expressed; however, the effects of p53 on LMP1 expression is not clear. We find LMP1 expression to be associated with p53 expression in EBV-transformed cells under physiological and DNA damaging conditions. DNA damage stimulates LMP1 expression, and p53 is required for the stimulation. Ectopic p53 stimulates endogenous LMP1 expression. Moreover, endogenous LMP1 blocks DNA damage-mediated apoptosis. Regarding the mechanism of p53-mediated LMP1 expression, we find that interferon regulatory factor 5 (IRF5), a direct target of p53, is associated with both p53 and LMP1. IRF5 binds to and activates a LMP1 promoter reporter construct. Ectopic IRF5 increases the expression of LMP1, while knockdown of IRF5 leads to reduction of LMP1. Furthermore, LMP1 blocks IRF5-mediated apoptosis in EBV-infected cells. All of the data suggest that cellular p53 stimulates viral LMP1 expression, and IRF5 may be one of the factors for p53-mediated LMP1 stimulation. LMP1 may subsequently block DNA damage- and IRF5-mediated apoptosis for the benefits of EBV. The mutual regulation between p53 and LMP1 may play an important role in EBV infection and latency and its related cancers.IMPORTANCE The tumor suppressor p53 is a critical cellular protein in response to various stresses and dictates cells for various responses, including apoptosis. This work suggests that an Epstein-Bar virus (EBV) principal viral oncogene is activated by cellular p53. The viral oncogene blocks p53-mediated adverse effects during viral infection and transformation. Therefore, the induction of the viral oncogene by p53 provides a means for the virus to cope with infection and DNA

  5. MicroRNA-34a is a potent tumor suppressor molecule in vivo in neuroblastoma

    LENUS (Irish Health Repository)

    Tivnan, Amanda

    2011-01-25

    ABSTRACT Background Neuroblastoma is a paediatric cancer which originates from precursor cells of the sympathetic nervous system and accounts for 15% of childhood cancer mortalities. With regards to the role of miRNAs in neuroblastoma, miR-34a, mapping to a chromosome 1p36 region that is commonly deleted, has been found to act as a tumor suppressor through targeting of numerous genes associated with cell proliferation and apoptosis. Methods A synthetic miR-34a (or negative control) precursor molecule was transfected into NB1691luc and SK-N-ASluc neuroblastoma cells. Quantitative PCR was used to verify increased miR-34a levels in NB1691luc and SK-N-ASluc cell lines prior to in vitro and in vivo analysis. In vitro analysis of the effects of miR-34a over expression on cell growth, cell cycle and phosphoprotein activation in signal transduction pathways was performed. Neuroblastoma cells over expressing miR-34a were injected retroperitoneally into immunocompromised CB17-SCID mice and tumor burden was assessed over a 21 day period by measuring bioluminescence (photons\\/sec\\/cm2). Results Over expression of miR-34a in both NB1691luc and SK-N-ASluc neuroblastoma cell lines led to a significant decrease in cell number relative to premiR-negative control treated cells over a 72 hour period. Flow cytometry results indicated that miR-34a induced cell cycle arrest and subsequent apoptosis activation. Phosphoprotein analysis highlighted key elements involved in signal transduction, whose activation was dysregulated as a result of miR-34a introduction into cells. As a potential mechanism of miR-34a action on phosphoprotein levels, we demonstrate that miR-34a over-expression results in a significant reduction of MAP3K9 mRNA and protein levels. Although MAP3K9 is a predicted target of miR-34a, direct targeting could not be validated with luciferase reporter assays. Despite this fact, any functional effects of reduced MAP3K9 expression as a result of miR-34a would be expected to

  6. Identification of myeloid derived suppressor cells in the peripheral blood of tumor bearing dogs

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    Sherger Matthew

    2012-10-01

    Full Text Available Abstract Background Myeloid derived suppressor cells (MDSCs are a recently described population of immune cells that significantly contribute to the immunosuppression seen in cancer patients. MDSCs are one of the most important factors that limit the efficacy of cancer immunotherapy (e.g. cancer vaccines and MDSC levels are increased in cancer in multiple species. Identifying and targeting MDSCs is actively being investigated in the field of human oncology and is increasingly being investigated in veterinary oncology. The treatment of canine cancer not only benefits dogs, but is being used for translational studies evaluating and modifcying candidate therapies for use in humans. Thus, it is necessary to understand the immune alterations seen in canine cancer patients which, to date, have been relatively limited. This study investigates the use of commercially available canine antibodies to detect an immunosuppressive (CD11blow/CADO48low cell population that is increased in the peripheral blood of tumor-bearing dogs. Results Commercially available canine antibodies CD11b and CADO48A were used to evaluate white blood cells from the peripheral blood cells of forty healthy control dogs and forty untreated, tumor-bearing dogs. Tumor-bearing dogs had a statistically significant increase in CD11blow/CADO48Alow cells (7.9% as compared to the control dogs (3.6%. Additionally, sorted CD11blow/CADO48Alow generated in vitro suppressed the proliferation of canine lymphocytes. Conclusions The purpose of this study was aimed at identifying potential canine specific markers for identifying MDSCs in the peripheral blood circulation of dogs. This study demonstrates an increase in a unique CD11blow/CADO48Alow cell population in tumor-bearing dogs. This immunophenotype is consistent with described phenotypes of MDSCs in other species (i.e. mice and utilizes commercially available canine-specific antibodies. Importantly, CD11blow/CADO48Alow from a tumor environment

  7. Identification of myeloid derived suppressor cells in the peripheral blood of tumor bearing dogs.

    Science.gov (United States)

    Sherger, Matthew; Kisseberth, William; London, Cheryl; Olivo-Marston, Susan; Papenfuss, Tracey L

    2012-10-31

    Myeloid derived suppressor cells (MDSCs) are a recently described population of immune cells that significantly contribute to the immunosuppression seen in cancer patients. MDSCs are one of the most important factors that limit the efficacy of cancer immunotherapy (e.g. cancer vaccines) and MDSC levels are increased in cancer in multiple species. Identifying and targeting MDSCs is actively being investigated in the field of human oncology and is increasingly being investigated in veterinary oncology. The treatment of canine cancer not only benefits dogs, but is being used for translational studies evaluating and modifying candidate therapies for use in humans. Thus, it is necessary to understand the immune alterations seen in canine cancer patients which, to date, have been relatively limited. This study investigates the use of commercially available canine antibodies to detect an immunosuppressive (CD11b low/CADO48 low) cell population that is increased in the peripheral blood of tumor-bearing dogs. Commercially available canine antibodies CD11b and CADO48A were used to evaluate white blood cells from the peripheral blood cells of forty healthy control dogs and forty untreated, tumor-bearing dogs. Tumor-bearing dogs had a statistically significant increase in CD11b low/CADO48A low cells (7.9%) as compared to the control dogs (3.6%). Additionally, sorted CD11b low/CADO48A low generated in vitro suppressed the proliferation of canine lymphocytes. The purpose of this study was aimed at identifying potential canine specific markers for identifying MDSCs in the peripheral blood circulation of dogs. This study demonstrates an increase in a unique CD11b low/CADO48A low cell population in tumor-bearing dogs. This immunophenotype is consistent with described phenotypes of MDSCs in other species (i.e. mice) and utilizes commercially available canine-specific antibodies. Importantly, CD11b low/CADO48A low from a tumor environment suppress the proliferation of lymphocytes

  8. Malignant Trigeminal Nerve Sheath Tumor and Anaplastic Astrocytoma Collision Tumor with High Proliferative Activity and Tumor Suppressor P53 Expression

    Directory of Open Access Journals (Sweden)

    Maher Kurdi

    2014-01-01

    Full Text Available Background. The synchronous development of two primary brain tumors of distinct cell of origin in close proximity or in contact with each other is extremely rare. We present the first case of collision tumor with two histological distinct tumors. Case Presentation. A 54-year-old woman presented with progressive atypical left facial pain and numbness for 8 months. MRI of the brain showed left middle cranial fossa heterogeneous mass extending into the infratemporal fossa. At surgery, a distinct but intermingled intra- and extradural tumor was demonstrated which was completely removed through left orbitozygomatic-temporal craniotomy. Histopathological examination showed that the tumor had two distinct components: malignant nerve sheath tumor of the trigeminal nerve and temporal lobe anaplastic astrocytoma. Proliferative activity and expressed tumor protein 53 (TP53 gene mutations were demonstrated in both tumors. Conclusions. We describe the first case of malignant trigeminal nerve sheath tumor (MTNST and anaplastic astrocytoma in collision and discuss the possible hypothesis of this rare occurrence. We propose that MTNST, with TP53 mutation, have participated in the formation of anaplastic astrocytoma, or vice versa.

  9. Slimming down fat makes neuropathic hippo: the Fat/Hippo tumor suppressor pathway protects adult neurons through regulation of autophagy.

    Science.gov (United States)

    Calamita, Piera; Fanto, Manolis

    2011-08-01

    Polyglutamine diseases are accompanied by large-scale alterations of transcription that may be responsible for neurodegeneration. We have monitored early transcriptional alterations in a Drosophila model for dentatorubral-pallidoluysian atrophy (DRPLA) and reported the critical downregulation of the fat tumor suppressor gene. We show that, besides partially mediating neurodegeneration in the Drosophila model for DRPLA, fat and the downstream hippo pathway are essential for adult neuronal homeostasis. This function of the Fat/Hippo pathway is independent of the well-established actions on proliferation and cell polarity; rather it has an impact upon autophagy, which is blocked and ineffective in fat/hippo mutants. These findings reveal the unexpected role in postmitotic neuronal homeostasis of a tumor suppressor pathway and hint at a new player involved directly or indirectly in the regulation of autophagy.

  10. Single-Molecule characterization of oligomerization kinetics and equilibria of the tumor suppressor p53.

    Science.gov (United States)

    Rajagopalan, Sridharan; Huang, Fang; Fersht, Alan R

    2011-03-01

    The state of oligomerization of the tumor suppressor p53 is an important factor in its various biological functions. It has a well-defined tetramerization domain, and the protein exists as monomers, dimers and tetramers in equilibrium. The dissociation constants between oligomeric forms are so low that they are at the limits of measurement by conventional methods in vitro. Here, we have used the high sensitivity of single-molecule methods to measure the equilibria and kinetics of oligomerization of full-length p53 and its isolated tetramerization domain, p53tet, at physiological temperature, pH and ionic strength using fluorescence correlation spectroscopy (FCS) in vitro. The dissociation constant at 37 °C for tetramers dissociating into dimers for full-length p53 was 50 ± 7 nM, and the corresponding value for dimers into monomers was 0.55 ± 0.08 nM. The half-lives for the two processes were 20 and 50 min, respectively. The equivalent quantities for p53tet were 150 ± 10 nM, 1.0 ± 0.14 nM, 2.5 ± 0.4 min and 13 ± 2 min. The data suggest that unligated p53 in unstressed cells should be predominantly dimeric. Single-molecule FCS is a useful procedure for measuring dissociation equilibria, kinetics and aggregation at extreme sensitivity.

  11. Long Non-coding RNA, PANDA, Contributes to the Stabilization of p53 Tumor Suppressor Protein.

    Science.gov (United States)

    Kotake, Yojiro; Kitagawa, Kyoko; Ohhata, Tatsuya; Sakai, Satoshi; Uchida, Chiharu; Niida, Hiroyuki; Naemura, Madoka; Kitagawa, Masatoshi

    2016-04-01

    P21-associated noncoding RNA DNA damage-activated (PANDA) is induced in response to DNA damage and represses apoptosis by inhibiting the function of nuclear transcription factor Y subunit alpha (NF-YA) transcription factor. Herein, we report that PANDA affects regulation of p53 tumor-suppressor protein. U2OS cells were transfected with PANDA siRNAs. At 72 h post-transfection, cells were subjected to immunoblotting and quantitative reverse transcription-polymerase chain reaction. Depletion of PANDA was associated with decreased levels of p53 protein, but not p53 mRNA. The stability of p53 protein was markedly reduced by PANDA silencing. Degradation of p53 protein by silencing PANDA was prevented by treatment of MG132, a proteasome inhibitor. Moreover, depletion of PANDA prevented accumulation of p53 protein, as a result of DNA damage, induced by the genotoxic agent etoposide. These results suggest that PANDA stabilizes p53 protein in response to DNA damage, and provide new insight into the regulatory mechanisms of p53. Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  12. Structure of the SCAN domain from the tumor suppressor protein MZF1.

    Science.gov (United States)

    Peterson, Francis C; Hayes, Paulette L; Waltner, Jeanette K; Heisner, Alicia K; Jensen, Davin R; Sander, Tara L; Volkman, Brian F

    2006-10-13

    The SCAN domain mediates interactions between members of a subfamily of zinc-finger transcription factors and is found in more than 60 C2H2 zinc finger genes in the human genome, including the tumor suppressor gene myeloid zinc finger 1 (MZF1). Glutathione-S-transferase pull-down assays showed that the MZF1 SCAN domain self-associates, and a Kd value of 600 nM was measured by intrinsic tryptophan fluorescence polarization. The MZF1 structure determined by NMR spectroscopy revealed a domain-swapped dimer. Each monomer consists of five alpha helices in two subdomains connected by the alpha2-alpha3 loop. Residues from helix 3 of each monomer compose the core of the dimer interface, while the alpha1-alpha2 loop and helix 2 pack against helices 3 and 5 from the opposing monomer. Comprehensive sequence analysis is coupled with the first high-resolution structure of a SCAN dimer to provide an initial view of the recognition elements that govern dimerization for this large family of transcription factors.

  13. Inactivation of tumor suppressor genes and cancer therapy: An evolutionary game theory approach.

    Science.gov (United States)

    Khadem, Heydar; Kebriaei, Hamed; Veisi, Zahra

    2017-06-01

    Inactivation of alleles in tumor suppressor genes (TSG) is one of the important issues resulting in evolution of cancerous cells. In this paper, the evolution of healthy, one and two missed allele cells is modeled using the concept of evolutionary game theory and replicator dynamics. The proposed model also takes into account the interaction rates of the cells as designing parameters of the system. Different combinations of the equilibrium points of the parameterized nonlinear system is studied and categorized into some cases. In each case, the interaction rates' values are suggested in a way that the equilibrium points of the replicator dynamics are located on an appropriate region of the state space. Based on the suggested interaction rates, it is proved that the system doesn't have any undesirable interior equilibrium point as well. Therefore, the system will converge to the desirable region, where there is a scanty level of cancerous cells. In addition, the proposed conditions for interaction rates guarantee that, when a trajectory of the system reaches the boundaries, then it will stay there forever which is a desirable property since the equilibrium points have been already located on the boundaries, appropriately. The simulation results show the effectiveness of the suggestions in the elimination of the cancerous cells in different scenarios. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Targeting Inhibitors of the Tumor Suppressor PP2A for the Treatment of Pancreatic Cancer

    Science.gov (United States)

    Farrell, Amy S.; Allen-Petersen, Brittany; Daniel, Colin J.; Wang, Xiaoyan; Wang, Zhiping; Rodriguez, Sarah; Impey, Soren; Oddo, Jessica; Vitek, Michael P.; Lopez, Charles; Christensen, Dale J.; Sheppard, Brett; Sears, Rosalie C.

    2014-01-01

    Pancreatic cancer is a deadly disease that is usually diagnosed in the advanced stages when few effective therapies are available. Given the aggressive clinical course of this disease and lack of good treatment options, the development of new therapeutic agents for the treatment of pancreatic cancer is of the upmost importance. Several pathways shown to contribute to pancreatic cancer progression are negatively regulated by the tumor suppressor, protein phosphatase 2A (PP2A). Here, the endogenous inhibitors of PP2A, SET (also known as I2PP2A) and Cancerous Inhibitor of PP2A (CIP2A), were shown to be overexpressed in human pancreatic cancer, contributing to decreased PP2A activity, and overexpression and stabilization of the oncoprotein c-Myc, a key PP2A target. Knockdown of SET or CIP2A increases PP2A activity, increases c-Myc degradation, and decreases the tumorigenic potential of pancreatic cancer cell lines both in vitro and in vivo. Moreover, treatment with a novel SET inhibitor, OP449, pharmacologically recapitulates the phenotypes and significantly reduces proliferation and tumorigenic potential of several pancreatic cancer cell lines, with an accompanying attenuation of cell growth and survival signaling. Furthermore, primary cells from pancreatic cancer patients were sensitive to OP449 treatment, indicating that PP2A regulated pathways are highly relevant to this deadly disease. PMID:24667985

  15. The Blk pathway functions as a tumor suppressor in chronic myeloid leukemia stem cells

    Science.gov (United States)

    Zhang, Haojian; Peng, Cong; Hu, Yiguo; Li, Huawei; Sheng, Zhi; Chen, Yaoyu; Sullivan, Con; Cerny, Jan; Hutchinson, Lloyd; Higgins, Anne; Miron, Patricia; Zhang, Xueqing; Brehm, Michael; Li, Dongguang; Green, Michael R.; Li, Shaoguang

    2012-01-01

    A therapeutic strategy for treating cancer is to target and eradicate cancer stem cells (CSCs) without harming their normal stem cell counterparts. The success of this approach relies on identification of molecular pathways that selectively regulate CSC function. Using BCR-ABL-induced chronic myeloid leukemia (CML) as a disease model for CSCs, we show that BCR-ABL down-regulates the B lymphoid kinase (Blk) gene through c-Myc in leukemia stem cells (LSCs) in CML mice and that Blk functions as a tumor suppressor in LSCs but does not affect normal hematopoietic stem cells (HSCs) or hematopoiesis. Blk suppresses LSC function through a pathway involving an upstream regulator, Pax5, and a downstream effector, p27. Inhibition of this Blk pathway accelerates CML development, whereas increased activity of the Blk pathway delays CML development. Blk also suppresses human CML stem cells. Our results demonstrate the feasibility of selectively targeting LSCs, an approach that should be applicable to other cancers. PMID:22797726

  16. A restricted spectrum of mutations in the SMAD4 tumor-suppressor gene underlies Myhre syndrome.

    Science.gov (United States)

    Caputo, Viviana; Cianetti, Luciano; Niceta, Marcello; Carta, Claudio; Ciolfi, Andrea; Bocchinfuso, Gianfranco; Carrani, Eugenio; Dentici, Maria Lisa; Biamino, Elisa; Belligni, Elga; Garavelli, Livia; Boccone, Loredana; Melis, Daniela; Andria, Generoso; Gelb, Bruce D; Stella, Lorenzo; Silengo, Margherita; Dallapiccola, Bruno; Tartaglia, Marco

    2012-01-13

    Myhre syndrome is a developmental disorder characterized by reduced growth, generalized muscular hypertrophy, facial dysmorphism, deafness, cognitive deficits, joint stiffness, and skeletal anomalies. Here, by performing exome sequencing of a single affected individual and coupling the results to a hypothesis-driven filtering strategy, we establish that heterozygous mutations in SMAD4, which encodes for a transducer mediating transforming growth factor β and bone morphogenetic protein signaling branches, underlie this rare Mendelian trait. Two recurrent de novo SMAD4 mutations were identified in eight unrelated subjects. Both mutations were missense changes altering Ile500 within the evolutionary conserved MAD homology 2 domain, a well known mutational hot spot in malignancies. Structural analyses suggest that the substituted residues are likely to perturb the binding properties of the mutant protein to signaling partners. Although SMAD4 has been established as a tumor suppressor gene somatically mutated in pancreatic, gastrointestinal, and skin cancers, and germline loss-of-function lesions and deletions of this gene have been documented to cause disorders that predispose individuals to gastrointestinal cancer and vascular dysplasias, the present report identifies a previously unrecognized class of mutations in the gene with profound impact on development and growth. Copyright © 2012 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  17. Targeting Calcium Signaling Induces Epigenetic Reactivation of Tumor Suppressor Genes in Cancer.

    Science.gov (United States)

    Raynal, Noël J-M; Lee, Justin T; Wang, Youjun; Beaudry, Annie; Madireddi, Priyanka; Garriga, Judith; Malouf, Gabriel G; Dumont, Sarah; Dettman, Elisha J; Gharibyan, Vazganush; Ahmed, Saira; Chung, Woonbok; Childers, Wayne E; Abou-Gharbia, Magid; Henry, Ryan A; Andrews, Andrew J; Jelinek, Jaroslav; Cui, Ying; Baylin, Stephen B; Gill, Donald L; Issa, Jean-Pierre J

    2016-03-15

    Targeting epigenetic pathways is a promising approach for cancer therapy. Here, we report on the unexpected finding that targeting calcium signaling can reverse epigenetic silencing of tumor suppressor genes (TSG). In a screen for drugs that reactivate silenced gene expression in colon cancer cells, we found three classical epigenetic targeted drugs (DNA methylation and histone deacetylase inhibitors) and 11 other drugs that induced methylated and silenced CpG island promoters driving a reporter gene (GFP) as well as endogenous TSGs in multiple cancer cell lines. These newly identified drugs, most prominently cardiac glycosides, did not change DNA methylation locally or histone modifications globally. Instead, all 11 drugs altered calcium signaling and triggered calcium-calmodulin kinase (CamK) activity, leading to MeCP2 nuclear exclusion. Blocking CamK activity abolished gene reactivation and cancer cell killing by these drugs, showing that triggering calcium fluxes is an essential component of their epigenetic mechanism of action. Our data identify calcium signaling as a new pathway that can be targeted to reactivate TSGs in cancer. ©2015 American Association for Cancer Research.

  18. With me or against me: Tumor suppressor and drug resistance activities of SAMHD1.

    Science.gov (United States)

    Herold, Nikolas; Rudd, Sean G; Sanjiv, Kumar; Kutzner, Juliane; Myrberg, Ida Hed; Paulin, Cynthia B J; Olsen, Thale Kristin; Helleday, Thomas; Henter, Jan-Inge; Schaller, Torsten

    2017-08-01

    Sterile alpha motif and histidine/aspartic acid domain-containing protein 1 (SAMHD1) is a (deoxy)guanosine triphosphate (dGTP/GTP)-activated deoxyribonucleoside triphosphate (dNTP) triphosphohydrolase involved in cellular dNTP homoeostasis. Mutations in SAMHD1 have been associated with the hyperinflammatory disease Aicardi-Goutières syndrome (AGS). SAMHD1 also limits cells' permissiveness to infection with diverse viruses, including human immunodeficiency virus (HIV-1), and controls endogenous retroviruses. Increasing evidence supports the role of SAMHD1 as a tumor suppressor. However, SAMHD1 also can act as a resistance factor to nucleoside-based chemotherapies by hydrolyzing their active triphosphate metabolites, thereby reducing response of various malignancies to these anticancer drugs. Hence, informed cancer therapies must take into account the ambiguous properties of SAMHD1 as both an inhibitor of uncontrolled proliferation and a resistance factor limiting the efficacy of anticancer treatments. Here, we provide evidence that SAMHD1 is a double-edged sword for patients with acute myelogenous leukemia (AML). Our time-dependent analyses of The Cancer Genome Atlas (TCGA) AML cohort indicate that high expression of SAMHD1, even though it critically limits the efficacy of high-dose ara-C therapy, might be associated with more favorable disease progression. Copyright © 2017 ISEH - International Society for Experimental Hematology. Published by Elsevier Inc. All rights reserved.

  19. RASSF5: An MST activator and tumor suppressor in vivo but opposite in vitro.

    Science.gov (United States)

    Liao, Tsung-Jen; Tsai, Chung-Jung; Jang, Hyunbum; Fushman, David; Nussinov, Ruth

    2016-12-01

    Is RASSF5 a tumor suppressor or activator? RASSF5 links K-Ras and the Hippo pathway. Hippo's signaling promotes YAP1 phosphorylation and degradation. YAP1 overexpression promotes cancer. Most reports point to RASSF5 suppressing cancer; however, some point to its promoting cancer. Our mechanistic view explains how RASSF5 can activate MST1/2 and suppress cancer in vivo; but inhibits MST1/2 in vitro. We propose that both activation and inhibition of MST1/2 can take place via SARAH heterodimerization. Our thesis in vivo, membrane-anchored Ras dimers (or nanoclusters) can promote SARAH domain heterodimerization, Raf-like MST1/2 kinase domain homodimerization and trans-autophosphorylation. In contrast, in vitro, K-Ras binding also releases the RASSF5 SARAH stimulating MST1/2's SARAH heterodimerization; however, without membrane, no MST1/2 kinase domain homodimerization/trans-autophosphorylation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Identification of novel driver tumor suppressors through functional interrogation of putative passenger mutations in colorectal cancer.

    Science.gov (United States)

    Zhang, Lu; Komurov, Kakajan; Wright, Woodring E; Shay, Jerry W

    2013-02-01

    Cancer genome sequencing efforts are leading to the identification of genetic mutations in many types of malignancy. However, the majority of these genetic alterations have been considered random passengers that do not directly contribute to tumorigenesis. We have previously conducted a soft agar-based short hairpin RNA (shRNA) screen within colorectal cancer (CRC) candidate driver genes (CAN-genes) using a karyotypically diploid hTERT- and CDK4-immortalized human colonic epithelial cell (HCEC) model and discovered that depletion of 65 of the 151 CAN-genes enhanced anchorage-independent growth in HCECs with ectopic expression of K-Ras(V12) and/or TP53 knockdown. We now constructed an interaction map of the confirmed CAN-genes with CRC non-CAN-genes and screened for functional tumor suppressors. Remarkably, depletion of 15 out of 25 presumed passenger genes that interact with confirmed CAN-genes (60%) promoted soft agar growth in HCECs with TP53 knockdown compared to only 7 out of 55 (12.5%) of presumed passenger genes that do not interact. We have thus demonstrated a pool of driver mutations among the putative CRC passenger/incidental mutations, establishing the importance of employing biological filters, in addition to bioinformatics, to identify driver mutations. Copyright © 2012 UICC.

  1. The FHIT gene product: tumor suppressor and genome ‘caretaker’

    Science.gov (United States)

    Waters, Catherine E.; Saldivar, Joshua C.; Hosseini, Seyed Ali; Huebner, Kay

    2014-01-01

    The FHIT gene at FRA3B is one of the earliest and most frequently altered genes in the majority of human cancers. It was recently discovered that the FHIT gene is not the most fragile locus in epithelial cells, the cell of origin for most Fhit negative cancers, eroding support for past claims that deletions at this locus are simply passenger events that are carried along in expanding cancer clones, due to extreme vulnerability to DNA damage rather than to loss of FHIT function. Indeed, recent reports have reconfirmed FHIT as a tumor suppressor gene with roles in apoptosis and prevention of the epithelial-mesenchymal transition. Other recent works have identified a novel role for the FHIT gene product, Fhit, as a genome ‘caretaker.’ Loss of this caretaker function leads to nucleotide imbalance, spontaneous replication stress, and DNA breaks. Because Fhit loss-induced DNA damage is “checkpoint blind,” cells accumulate further DNA damage during subsequent cell cycles, accruing global genome instability that could facilitate oncogenic mutation acquisition and expedite clonal expansion. Loss of Fhit activity therefore induces a mutator phenotype. Evidence for FHIT as a mutator gene is discussed in light of these recent investigations of Fhit loss and subsequent genome instability. PMID:25283145

  2. All along the watchtower: is the cilium a tumor suppressor organelle?

    Science.gov (United States)

    Mans, Dorus A; Voest, Emile E; Giles, Rachel H

    2008-12-01

    Cilia or flagella have been around since almost the beginning of life, and have now developed specialized cell-type specific functions from locomotion to acting as environmental sensors participating in cell signalling. Genetic defects affecting cilia result in a myriad of pathological instances, including infertility, obesity, blindness, deafness, skeletal malformations, and lung problems. However, the consistency in which the common kidney cyst is coupled with cilia dysfunction has raised interest in the possibility that ciliary dysfunction might contribute to other neoplasms as well. A suite of recent papers convincingly linking cilia to hedgehog signalling, platelet-derived growth factor signalling, Wnt signalling and the von Hippel-Lindau tumor suppressor protein has rapidly expanded the knowledge base connecting cilia to cancer. We propose that these data support the notion of the cilium as a cellular Watchtower, whose absence can be an initiating event in neoplastic growth. Furthermore, we predict that we are just now seeing the tip of the iceberg, and that the list of cancers associated with altered ciliary signalling will grow exponentially in the next few years.

  3. Expression profiles of SnoN in normal and cancerous human tissues support its tumor suppressor role in human cancer.

    Directory of Open Access Journals (Sweden)

    Nadine S Jahchan

    Full Text Available SnoN is a negative regulator of TGF-β signaling and also an activator of the tumor suppressor p53 in response to cellular stress. Its role in human cancer is complex and controversial with both pro-oncogenic and anti-oncogenic activities reported. To clarify its role in human cancer and provide clinical relevance to its signaling activities, we examined SnoN expression in normal and cancerous human esophageal, ovarian, pancreatic and breast tissues. In normal tissues, SnoN is expressed in both the epithelium and the surrounding stroma at a moderate level and is predominantly cytoplasmic. SnoN levels in all tumor epithelia examined are lower than or similar to that in the matched normal samples, consistent with its anti-tumorigenic activity in epithelial cells. In contrast, SnoN expression in the stroma is highly upregulated in the infiltrating inflammatory cells in high-grade esophageal and ovarian tumor samples, suggesting that SnoN may potentially promote malignant progression through modulating the tumor microenvironment in these tumor types. The overall levels of SnoN expression in these cancer tissues do not correlate with the p53 status. However, in human cancer cell lines with amplification of the snoN gene, a strong correlation between increased SnoN copy number and inactivation of p53 was detected, suggesting that the tumor suppressor SnoN-p53 pathway must be inactivated, either through downregulation of SnoN or inactivation of p53, in order to allow cancer cell to proliferate and survive. These data strongly suggest that SnoN can function as a tumor suppressor at early stages of tumorigenesis in human cancer tissues.

  4. Purification of the NF2 tumor suppressor protein from human erythrocytes.

    Science.gov (United States)

    Jindal, Hitesh K; Yoshinaga, Kazumi; Seo, Pil-Soo; Lutchman, Mohini; Dion, Patrick A; Rouleau, Guy A; Hanada, Toshihiko; Chishti, Athar H

    2006-11-01

    Neurofibromatosis type 2 (NF2) is an autosomal dominant disease predisposing individuals to the risk of developing tumors of cranial and spinal nerves. The NF2 tumor suppressor protein, known as Merlin/Schwanomin, is a member of the protein 4.1 superfamily that function as links between the cytoskeleton and the plasma membrane. Upon selective extraction of membrane-associated proteins from erythrocyte plasma membrane (ghosts) using low ionic strength solution, the bulk of NF2 protein remains associated with the spectrin-actin depleted inside-out-vesicles. Western blot analysis showed a approximately 70 kDa polypeptide in the erythrocyte plasma membrane. Furthermore, quantitative removal of NF2 protein from the inside-out-vesicles was achieved using 1.0 M potassium iodide, a treatment known to remove tightly-bound peripheral membrane proteins. These results suggest a novel mode of NF2 protein association with the erythrocyte membrane that is distinct from the known membrane interactions of protein 4.1. Based on these biochemical properties, several purification strategies were devised to isolate native NF2 protein from human erythrocyte ghosts. Using purified and recombinant NF2 protein as internal standards, we quantified approximately 41-65,000 molecules of NF2 protein per erythrocyte. We provide evidence for the presence of NF2 protein in the human erythrocyte membrane. The identification of NF2 protein in the human erythrocyte membrane will make it feasible to discover novel interactions of NF2 protein utilizing powerful techniques of erythrocyte biochemistry and genetics in mammalian cells.

  5. miR-137 acts as a tumor suppressor in astrocytoma by targeting RASGRF1.

    Science.gov (United States)

    Deng, Danni; Xue, Lian; Shao, Naiyuan; Qu, Hongtao; Wang, Qiang; Wang, Suinuan; Xia, Xiwei; Yang, Yilin; Zhi, Feng

    2016-03-01

    Astrocytoma is one of the most common primary central nervous system tumors and has both high mortality and a poor 5-year survival rate. MicroRNAs (miRNAs) play important roles in carcinogenesis by acting on multiple signaling pathways. Although we have demonstrated that miR-137 is downregulated in astrocytoma tissues, the role of miR-137 in astrocytoma still remains unknown. In the present study, we aimed to investigate the function of miR-137 and its possible target genes in astrocytoma. miR-137 was significantly downregulated in astrocytoma tissues, and its expression level was inversely correlated with the clinical stage. Restoring miR-137 was able to dramatically inhibit cell proliferation, migration, and invasion and enhance apoptosis in vitro, whereas silencing its expression inhibited these processes. By overexpressing or inhibiting miR-137 in cancer cells, we experimentally confirmed that miR-137 directly recognized the 3'-UTR (3'-untranslated region) of the RASGRF1 (Ras protein-specific guanine nucleotide-releasing factor 1) transcript and regulated RASGRF1 expression. Furthermore, an inverse correlation was observed between miR-137 levels and RASGRF1 protein levels, but not mRNA levels, in astrocytoma samples. The silencing of RASGRF1 resulted in similar effects to miR-137 restoration in cancer cells. Finally, overexpression of RASGRF1 rescued the inhibitory effects of miR-137. Taken together, our results indicate that miR-137 acts as a tumor suppressor in astrocytoma by targeting RASGRF1. These findings suggest that miR-137 may serve as a novel therapeutic target in astrocytoma treatment.

  6. Loss of the tumor suppressor Hace1 leads to ROS-dependent glutamine addiction

    Science.gov (United States)

    Cetinbas, Naniye; Daugaard, Mads; Mullen, Andrew; Hajee, Shamil; Rotblat, Barak; Lopez, Alejandra; Li, Amy; DeBerardinis, Ralph J; Sorensen, Poul H

    2014-01-01

    Cellular transformation is associated with altered glutamine (Gln) metabolism. Tumor cells utilize Gln in the tricarboxylic acid (TCA) cycle to maintain sufficient pools of biosynthetic precursors to support rapid growth and proliferation. However, Gln metabolism also generates NADPH, and Gln-derived glutamate is used for synthesis of glutathione (GSH). Since both NADPH and GSH are antioxidants, Gln may also contribute to redox balance in transformed cells. The Hace1 E3 ligase is a tumor suppressor inactivated in diverse human cancers. Hace1 targets the Rac1 GTPase for degradation at Rac1-dependent NADPH oxidase complexes, blocking superoxide generation by the latter. Consequently, loss of Hace1 increases reactive oxygen species (ROS) levels in vitro and in vivo. Given the link between Hace1 loss and increased ROS, we investigated whether genetic inactivation of Hace1 alters Gln metabolism. We demonstrate that mouse embryonic fibroblasts (MEFs) derived from Hace1-/- mice are highly sensitive to Gln withdrawal, leading to enhanced cell death compared to wild type (wt) MEFs, and Gln depletion or chemical inhibition of Gln uptake block soft agar colony formation by Hace1-/- MEFs. Hace1-/- MEFs exhibit increased Gln uptake and ammonia secretion, and metabolic labeling using 13C-Gln revealed that Hace1 loss increases incorporation of Gln carbons into TCA cycle intermediates. Gln starvation markedly increases ROS levels in Hace1-/- but not in wt MEFs, and treatment with the antioxidant N-acetyl cysteine (NAC) or the TCA cycle intermediate oxaloacetate efficiently rescues Gln starvation-induced ROS elevation and cell death in Hace1-/- MEFs. Finally, Gln starvation increases superoxide levels in Hace1-/- MEFs, and NADPH oxidase inhibitors block the induction of superoxide and cell death by Gln starvation. Together, these results suggest that increased ROS production due to Hace1 loss leads to Gln addiction as a mechanism to cope with increased ROS-induced oxidative stress

  7. Self-association of the WT1 tumor suppressor gene product

    Energy Technology Data Exchange (ETDEWEB)

    Bruening, W.; Nakagama, H.: Bardessy, N. [McGill Univ., Montreal (Canada)] [and others

    1994-09-01

    Wilms` tumor (WT), an embryonal malignancy of the kidney, occurs most frequently in children under the age of 5 years, affecting {approximately}1 in 10,000 individuals. The WT1 tumor suppressor gene, residing at 11p13, is structurally altered in {approximately}10-15% of WT cases. Individuals with germline mutations within the WT1 gene suffer from predisposition to WT and developmental defects of the urogenital system. Patients with heterozygous deletions of the WT1 gene, or mutations predicted to cause inactivation of one WT1 allele, suffer relatively mild genital system defects (notably hypospadias and cryptorchidism in males) and a predisposition to WT. These results suggest that developing genital system development is sensitive to the absolute concentrations of the WT1 gene products. Patients with missense mutations within the WT1 gene, however, can suffer from a much more severe disorder known as Denys-Drash syndrome (DDS). This syndrome is characterized by intersex disorders, renal nephropathy, and a predisposition to WTs. The increased severity of the developmental defects associated with DDS, compared to those individuals with mild genital system anomalies and WTs, suggests that mutations defined in patients with DDS behave in a dominant-negative fashion. We have identified a novel WT1 mutation in a patient with DDS. This mutation, predicted to produce a truncated WT1 polypeptide encompassing exons 1, 2, and 3, defines a domain capable of behaving as an antimorph. We have also demonstrated that WT1 can self-associate in vivo using yeast two-hybrid systems. Deletion analysis have mapped the interacting domains to the amino terminus of the WT1 polypeptide, within exons 1 and 2. These results provide a molecular mechanism to explain how WT1 mutations can function in a dominant-negative fashion to eliminate wild-type WT1 activity, leading to DDS.

  8. Human Ovarian Cancer Stroma Contains Luteinized Theca Cells Harboring Tumor Suppressor Gene GT198 Mutations*

    Science.gov (United States)

    Peng, Min; Zhang, Hao; Jaafar, Lahcen; Risinger, John I.; Huang, Shuang; Mivechi, Nahid F.; Ko, Lan

    2013-01-01

    Ovarian cancer is a highly lethal gynecological cancer, and its causes remain to be understood. Using a recently identified tumor suppressor gene, GT198 (PSMC3IP), as a unique marker, we searched for the identity of GT198 mutant cells in ovarian cancer. GT198 has germ line mutations in familial and early onset breast and ovarian cancers and recurrent somatic mutations in sporadic fallopian tube cancers. GT198 protein has been shown as a steroid hormone receptor coregulator and also as a crucial factor in DNA repair. In this study, using GT198 as a marker for microdissection, we find that ovarian tumor stromal cells harboring GT198 mutations are present in various types of ovarian cancer including high and low grade serous, endometrioid, mucinous, clear cell, and granulosa cell carcinomas and in precursor lesions such as inclusion cysts. The mutant stromal cells consist of a luteinized theca cell lineage at various differentiation stages including CD133+, CD44+, and CD34+ cells, although the vast majority of them are differentiated overexpressing steroidogenic enzyme CYP17, a theca cell-specific marker. In addition, wild type GT198 suppresses whereas mutant GT198 protein stimulates CYP17 expression. The chromatin-bound GT198 on the human CYP17 promoter is decreased by overexpressing mutant GT198 protein, implicating the loss of wild type suppression in mutant cells. Together, our results suggest that GT198 mutant luteinized theca cells overexpressing CYP17 are common in ovarian cancer stroma. Because first hit cancer gene mutations would specifically mark cancer-inducing cells, the identification of mutant luteinized theca cells may add crucial evidence in understanding the cause of human ovarian cancer. PMID:24097974

  9. Human ovarian cancer stroma contains luteinized theca cells harboring tumor suppressor gene GT198 mutations.

    Science.gov (United States)

    Peng, Min; Zhang, Hao; Jaafar, Lahcen; Risinger, John I; Huang, Shuang; Mivechi, Nahid F; Ko, Lan

    2013-11-15

    Ovarian cancer is a highly lethal gynecological cancer, and its causes remain to be understood. Using a recently identified tumor suppressor gene, GT198 (PSMC3IP), as a unique marker, we searched for the identity of GT198 mutant cells in ovarian cancer. GT198 has germ line mutations in familial and early onset breast and ovarian cancers and recurrent somatic mutations in sporadic fallopian tube cancers. GT198 protein has been shown as a steroid hormone receptor coregulator and also as a crucial factor in DNA repair. In this study, using GT198 as a marker for microdissection, we find that ovarian tumor stromal cells harboring GT198 mutations are present in various types of ovarian cancer including high and low grade serous, endometrioid, mucinous, clear cell, and granulosa cell carcinomas and in precursor lesions such as inclusion cysts. The mutant stromal cells consist of a luteinized theca cell lineage at various differentiation stages including CD133(+), CD44(+), and CD34(+) cells, although the vast majority of them are differentiated overexpressing steroidogenic enzyme CYP17, a theca cell-specific marker. In addition, wild type GT198 suppresses whereas mutant GT198 protein stimulates CYP17 expression. The chromatin-bound GT198 on the human CYP17 promoter is decreased by overexpressing mutant GT198 protein, implicating the loss of wild type suppression in mutant cells. Together, our results suggest that GT198 mutant luteinized theca cells overexpressing CYP17 are common in ovarian cancer stroma. Because first hit cancer gene mutations would specifically mark cancer-inducing cells, the identification of mutant luteinized theca cells may add crucial evidence in understanding the cause of human ovarian cancer.

  10. Impact of Natural Compounds on DNA Methylation Levels of the Tumor Suppressor Gene RASSF1A in Cancer

    OpenAIRE

    Dammann, Reinhard H.; Richter, Antje M.; Jiménez, Adriana P.; Woods, Michelle; Küster, Miriam; Witharana, Chamindri

    2017-01-01

    Epigenetic inactivation of tumor suppressor genes (TSG) is a fundamental event in the pathogenesis of human cancer. This silencing is accomplished by aberrant chromatin modifications including DNA hypermethylation of the gene promoter. One of the most frequently hypermethylated TSG in human cancer is the Ras Association Domain Family 1A (RASSF1A) gene. Aberrant methylation of RASSF1A has been reported in melanoma, sarcoma and carcinoma of different tissues. RASSF1A hypermethylation has been c...

  11. Loss of the tumor suppressor LKB1 promotes metabolic reprogramming of cancer cells via HIF-1α.

    Science.gov (United States)

    Faubert, Brandon; Vincent, Emma E; Griss, Takla; Samborska, Bozena; Izreig, Said; Svensson, Robert U; Mamer, Orval A; Avizonis, Daina; Shackelford, David B; Shaw, Reuben J; Jones, Russell G

    2014-02-18

    One of the major metabolic changes associated with cellular transformation is enhanced nutrient utilization, which supports tumor progression by fueling both energy production and providing biosynthetic intermediates for growth. The liver kinase B1 (LKB1) is a serine/threonine kinase and tumor suppressor that couples bioenergetics to cell-growth control through regulation of mammalian target of rapamycin (mTOR) activity; however, the influence of LKB1 on tumor metabolism is not well defined. Here, we show that loss of LKB1 induces a progrowth metabolic program in proliferating cells. Cells lacking LKB1 display increased glucose and glutamine uptake and utilization, which support both cellular ATP levels and increased macromolecular biosynthesis. This LKB1-dependent reprogramming of cell metabolism is dependent on the hypoxia-inducible factor-1α (HIF-1α), which accumulates under normoxia in LKB1-deficient cells and is antagonized by inhibition of mTOR complex I signaling. Silencing HIF-1α reverses the metabolic advantages conferred by reduced LKB1 signaling and impairs the growth and survival of LKB1-deficient tumor cells under low-nutrient conditions. Together, our data implicate the tumor suppressor LKB1 as a central regulator of tumor metabolism and growth control through the regulation of HIF-1α-dependent metabolic reprogramming.

  12. Protein tyrosine phosphatase receptor delta acts as a neuroblastoma tumor suppressor by destabilizing the aurora kinase a oncogene

    LENUS (Irish Health Repository)

    Meehan, Maria

    2012-02-05

    Abstract Background Protein tyrosine phosphatase receptor delta (PTPRD) is a member of a large family of protein tyrosine phosphatases which negatively regulate tyrosine phosphorylation. Neuroblastoma is a major childhood cancer arising from precursor cells of the sympathetic nervous system which is known to acquire deletions and alterations in the expression patterns of PTPRD, indicating a potential tumor suppressor function for this gene. The molecular mechanism, however, by which PTPRD renders a tumor suppressor effect in neuroblastoma is unknown. Results As a molecular mechanism, we demonstrate that PTPRD interacts with aurora kinase A (AURKA), an oncogenic protein that is over-expressed in multiple forms of cancer, including neuroblastoma. Ectopic up-regulation of PTPRD in neuroblastoma dephosphorylates tyrosine residues in AURKA resulting in a destabilization of this protein culminating in interfering with one of AURKA\\'s primary functions in neuroblastoma, the stabilization of MYCN protein, the gene of which is amplified in approximately 25 to 30% of high risk neuroblastoma. Conclusions PTPRD has a tumor suppressor function in neuroblastoma through AURKA dephosphorylation and destabilization and a downstream destabilization of MYCN protein, representing a novel mechanism for the function of PTPRD in neuroblastoma.

  13. 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

  14. Pharmacological activation of tumor suppressor, wild-type p53 as a promising strategy to fight cancer

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    Alicja Sznarkowska

    2010-08-01

    Full Text Available A powerful tumor suppressor – p53 protein is a transcription factor which plays a critical role in eliciting cellular responses to a variety of stress signals, including DNA damage, hypoxia and aberrant proliferative signals, such as oncogene activation. Since its discovery thirty one years ago, p53 has been connected to tumorigenesis as it accumulates in the transformed tumor cells. Cellular stress induces stabilization of p53 and promotes, depending on the stress level, cell cycle arrest or apoptosis in the irreversibly damaged cells. The p53 protein is found inactive in more than 50�0of human tumors either by enhanced proteasomal degradation or due to the inactivating point mutations in its gene. Numerous data indicate that low molecular weight compounds, identified by molecular modeling or in the functional, cell-based assays, efficiently activate non-mutated p53 in cancer cells which in consequence leads to their elimination due to p53-dependent apoptosis. In this work we describe the structure and cellular function of p53 as well as the latest discoveries on the compounds with high anti-tumor activities aiming at reactivation of the tumor suppressor function of p53.

  15. Bioinformatic Analysis of Circadian Expression of Oncogenes and Tumor Suppressor Genes

    Science.gov (United States)

    Salavaty, Abbas; Mohammadi, Niloufar; Shahmoradi, Mozhdeh; Naderi Soorki, Maryam

    2017-01-01

    Background: Circadian rhythms are physiological and behavioral cycles with a period of approximately 24 hours that control various functions including gene expression. Circadian disruption is associated with a variety of diseases, especially cancer. Although some of the oncogenes and tumor suppressor genes (TSGs) are known as clock-controlled genes (CCGs), the analysis and annotation of circadian expression of most human oncogenes and TSGs are still lacking. This study aims to investigate the circadian expression of a list of human oncogenes and TSGs. Methods: A bioinformatic analysis was conducted on a gene library comprising 120 genes to investigate the circadian expression of human oncogenes and TSGs. To achieve this purpose, the genotranscriptomic data were retrieved from COSMIC and analyzed by R statistical software. Furthermore, the acquired data were analyzed at the transcriptomic and proteomic levels using several publicly available databases. Also, the significance of all analyses was confirmed statistically. Results: Altogether, our results indicated that 7 human oncogenes/TSGs may be expressed and function in a circadian manner. These oncogenes/TSGs showed a circadian expression pattern at CircaDB database and associated with at least one of the circadian genes/CCGs based on both genotranscriptomic and correlation analyses. Conclusions: Although 4 of 7 finally outputted genes have been previously reported to be clock controlled, heretofore there is no report about the circadian expression of 3 other genes. Considering the importance of oncogenes/TSGs in the initiation and progression of cancer, further studies are suggested for the identification of exact circadian expression patterns of these 3 human oncogenes/TSGs. PMID:29276378

  16. BAX and tumor suppressor TRP53 are important in regulating mutagenesis in spermatogenic cells in mice.

    Science.gov (United States)

    Xu, Guogang; Vogel, Kristine S; McMahan, C Alex; Herbert, Damon C; Walter, Christi A

    2010-12-01

    During the first wave of spermatogenesis, and in response to ionizing radiation, elevated mutant frequencies are reduced to a low level by unidentified mechanisms. Apoptosis is occurring in the same time frame that the mutant frequency declines. We examined the role of apoptosis in regulating mutant frequency during spermatogenesis. Apoptosis and mutant frequencies were determined in spermatogenic cells obtained from Bax-null or Trp53-null mice. The results showed that spermatogenic lineage apoptosis was markedly decreased in Bax-null mice and was accompanied by a significantly increased spontaneous mutant frequency in seminiferous tubule cells compared to that of wild-type mice. Apoptosis profiles in the seminiferous tubules for Trp53-null were similar to control mice. Spontaneous mutant frequencies in pachytene spermatocytes and in round spermatids from Trp53-null mice were not significantly different from those of wild-type mice. However, epididymal spermatozoa from Trp53-null mice displayed a greater spontaneous mutant frequency compared to that from wild-type mice. A greater proportion of spontaneous transversions and a greater proportion of insertions/deletions 15 days after ionizing radiation were observed in Trp53-null mice compared to wild-type mice. Base excision repair activity in mixed germ cell nuclear extracts prepared from Trp53-null mice was significantly lower than that for wild-type controls. These data indicate that BAX-mediated apoptosis plays a significant role in regulating spontaneous mutagenesis in seminiferous tubule cells obtained from neonatal mice, whereas tumor suppressor TRP53 plays a significant role in regulating spontaneous mutagenesis between postmeiotic round spermatid and epididymal spermatozoon stages of spermiogenesis.

  17. Structural Studies of the SET Domain from RIZ1 Tumor Suppressor

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    Briknarova, Klara; Zhou, Xinliang; Satterthwait, Arnold C.; Hoyt, David W.; Ely, Kathryn R.; Huang, Shi

    2008-02-15

    Histone lysine methyltransferases (HKMTs) are involved in regulation of chromatin structure, and, as such, are important for longterm gene activation and repression that is associated with cell memory and establishment of cell-type specific transcriptional programs. Most HKMTs contain a SET domain, which is responsible for their catalytic activity. RIZ1 is a transcription regulator and tumor suppressor that catalyzes methylation of lysine 9 of histone H3 and contains a rather distinct SET domain. Similar SET domains, sometimes refererred to as PR (PRDI-BF1 and RIZ1 homology) domains, are also found in other proteins including Blimp-1/PRDI-BF1, MDS1-EVI1 and Meisetz. We determined the solution structure of the PR domain from RIZ1 and characterized its interaction with S-adenosyl homocysteine (SAH) and a peptide from histone H3. Despite low sequence identity with canonical SET domains, the PR domain displays a typical SET fold including a pseudo-knot at the C-terminus. The N-flanking sequence of RIZ1 PR domain adopts a novel conformation and interacts closely with the SET fold. The C-flanking sequence contains an α-helix that exhibits higher mobility than the SET fold and points away from the protein face that harbors active site in other SET domains. Residues that interact with the methylation cofactor in SET domains are not conserved in RIZ1 or other PR domains, and the SET fold of RIZ1 does not bind SAH. However, the PR domain of RIZ1 interacts specifically with a synthetic peptide comprising residues 1-20 of histone H3.

  18. Chemical principles additive model aligns low consensus DNA targets of p53 tumor suppressor protein.

    Science.gov (United States)

    Thayer, Kelly M; Han, In Sub M

    2017-06-01

    Computational prediction of the interaction between protein transcription factors and their cognate DNA binding sites in genomic promoters constitutes a formidable challenge in two situations: when the number of discriminatory interactions is small compared to the length of the binding site, and when DNA binding sites possess a poorly conserved consensus binding motif. The transcription factor p53 tumor suppressor protein and its target DNA exhibit both of these issues. From crystal structure analysis, only three discriminatory amino acid side chains contact the DNA for a binding site spanning ten base pairs. Furthermore, our analysis of a dataset of genome wide fragments binding to p53 revealed many sequences lacking the expected consensus. The low information content leads to an overestimation of binding sites, and the lack of conservation equates to a computational alignment problem. Within a fragment of DNA known to bind to p53, computationally locating the position of the site equates to aligning the DNA with the binding interface. From a molecular perspective, that alignment implies a specification of which DNA bases are interacting with which amino acid side chains, and aligning many sequences to the same protein interface concomitantly produces a multiple sequence alignment. From this vantage, we propose to cast prediction of p53 binding sites as an alignment to the protein binding surface with the novel approach of optimizing the alignment of DNA fragments to the p53 binding interface based on chemical principles. A scoring scheme based on this premise was successfully implemented to score a dataset of biological DNA fragments known to contain p53 binding sites. The results illuminate the mechanism of recognition for the protein-DNA system at the forefront of cancer research. These findings implicate that p53 may recognize its target binding sites via several different mechanisms which may include indirect readout. Copyright © 2017 Elsevier Ltd. All

  19. Bioinformatic Analysis of Circadian Expression of Oncogenes and Tumor Suppressor Genes.

    Science.gov (United States)

    Salavaty, Abbas; Mohammadi, Niloufar; Shahmoradi, Mozhdeh; Naderi Soorki, Maryam

    2017-01-01

    Circadian rhythms are physiological and behavioral cycles with a period of approximately 24 hours that control various functions including gene expression. Circadian disruption is associated with a variety of diseases, especially cancer. Although some of the oncogenes and tumor suppressor genes (TSGs) are known as clock-controlled genes (CCGs), the analysis and annotation of circadian expression of most human oncogenes and TSGs are still lacking. This study aims to investigate the circadian expression of a list of human oncogenes and TSGs. A bioinformatic analysis was conducted on a gene library comprising 120 genes to investigate the circadian expression of human oncogenes and TSGs. To achieve this purpose, the genotranscriptomic data were retrieved from COSMIC and analyzed by R statistical software. Furthermore, the acquired data were analyzed at the transcriptomic and proteomic levels using several publicly available databases. Also, the significance of all analyses was confirmed statistically. Altogether, our results indicated that 7 human oncogenes/TSGs may be expressed and function in a circadian manner. These oncogenes/TSGs showed a circadian expression pattern at CircaDB database and associated with at least one of the circadian genes/CCGs based on both genotranscriptomic and correlation analyses. Although 4 of 7 finally outputted genes have been previously reported to be clock controlled, heretofore there is no report about the circadian expression of 3 other genes. Considering the importance of oncogenes/TSGs in the initiation and progression of cancer, further studies are suggested for the identification of exact circadian expression patterns of these 3 human oncogenes/TSGs.

  20. Interleukin 33 in tumor microenvironment is crucial for the accumulation and function of myeloid-derived suppressor cells.

    Science.gov (United States)

    Xiao, Peng; Wan, Xiaopeng; Cui, Bijun; Liu, Yang; Qiu, Chenyang; Rong, Jiabing; Zheng, Mingzhu; Song, Yinjing; Chen, Luoquan; He, Jia; Tan, Qinchun; Wang, Xiaojia; Shao, Xiying; Liu, Yuhua; Cao, Xuetao; Wang, Qingqing

    Tumor-induced, myeloid-derived suppressor cells (MDSCs)-mediated immune dysfunction is an important mechanism that leads to tumor immune escape and the inefficacy of cancer immunotherapy. Importantly, tumor-infiltrating MDSCs have much stronger ability compared to MDSCs in the periphery. However, the mechanisms that tumor microenvironment induces the accumulation and function of MDSCs are poorly understood. Here, we report that Interleukin-33 (IL-33) - a cytokine which can be abundantly released in tumor tissues both in 4T1-bearing mice and breast cancer patients, is crucial for facilitating the expansion of MDSCs. IL-33 in tumor microenvironment reduces the apoptosis and sustains the survival of MDSCs through induction of autocrine secretion of GM-CSF, which forms a positive amplifying loop for MDSC accumulation. This is in conjunction with IL-33-driven induction of arginase-1 expression and activation of NF-κB and MAPK signaling in MDSCs which augments their immunosuppressive ability, and histone modifications were involved in IL-33 signaling in MDSCs. In ST2-/- mice, the defect of IL-33 signaling in MDSCs attenuates the immunosuppressive and pro-tumoral capacity of MDSCs. Our results identify IL-33 as a critical mediator that contributes to the abnormal expansion and enhanced immunosuppressive function of MDSCs within tumor microenvironment, which can be potentially targeted to reverse MDSC-mediated tumor immune evasion.

  1. Epigenetic silencing of MAL, a putative tumor suppressor gene, can contribute to human epithelium cell carcinoma

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    Zhang Jun

    2010-11-01

    Full Text Available Abstract Background To identify new and useful candidate biomarkers in head and neck squamous cell carcinoma (HNSCC, we performed a genome-wide survey and found that Myelin and lymphocyte-associated protein (MAL was a gene that was markedly down-regulated in HNSCC. Hence, we investigated the mechanism of MAL silencing and the effects of MAL on the proliferation, invasion, and apoptotic potential in HNSCC. Results MAL was significantly down-regulated in 91.7% of HNSCC specimens at the mRNA level as compared with adjacent normal tissues (P = 0.0004. Moreover, the relative transcript levels of the MAL gene were remarkably decreased by five-fold in nine HNSCC cell lines as compared with normal head and neck epithelium cells. MAL gene expression was restored in 44%, 67%, and 89% in HNSCC cell lines treated with TSA, 5-Aza-dC, and TSA plus 5-Aza-dC, respectively. Furthermore, bisulfate-treated DNA sequencing demonstrated that the two CpG islands (that is, M1 and M2 located in MAL promoter region were completely methylated in the HNSCC cell lines (CpG methylated ratio was more than 90%, and only one CpG island (that is, M1 was partially methylated in HNSCC tissues (CpG methylated ratio between 20% and 90%. A significant reduction in cell proliferation and a change in the cell cycle profile were also observed in MAL transfectants. Matrigel assay demonstrated that the invasiveness of HNSCC cells significantly decreased. A significant increase in the population of apoptotic cells was observed in MAL transfected cells. The exogenous expression of the MAL gene suppressed malignant phenotypes, while the cell death induced by MAL gene transfer was a result of apoptosis as demonstrated by the induction of cleavage of the poly (that is, ADP-ribose polymerase. Additionally, tumor growth was suppressed in cells expressing MAL as compared with cells not expressing MAL. Conclusion Our data suggest that the epigenetic inactivation of MAL, as a candidate tumor

  2. Effect of zinc supplementation on N-nitrosomethylbenzylamine-induced forestomach tumor development and progression in tumor suppressor-deficient mouse strains.

    Science.gov (United States)

    Sun, Jin; Liu, James; Pan, Xueliang; Quimby, Donald; Zanesi, Nicola; Druck, Teresa; Pfeifer, Gerd P; Croce, Carlo M; Fong, Louise Y; Huebner, Kay

    2011-03-01

    Zinc deficiency is associated with high incidences of esophageal and other cancers in humans and leads to a highly proliferative hyperplastic condition in the upper gastrointestinal tract in laboratory rodents. Zn replenishment reduces the incidence of lingual, esophageal and forestomach tumors in Zn-deficient rats and mice. While previous animal studies focused on Zn deficiency, we have investigated the effect of Zn supplementation on carcinogenesis in Zn-sufficient mice of wild-type and tumor suppressor-deficient mouse strains. All mice received N-nitrosomethylbenzylamine and half the mice of each strain then received Zn supplementation. At killing, mice without Zn supplementation had developed more tumors than Zn-supplemented mice: wild-type C57BL/6 mice developed an average of 7.0 versus 5.0 tumors for Zn supplemented (P < 0.05); Zn-supplemented Fhit-/- mice averaged 5.7 versus 8.0 for control mice (P < 0.01); Zn-supplemented Fhit-/-Nit1-/- mice averaged 5.4 versus 9.2 for control mice (P < 0.01) and Zn-supplemented Fhit-/-Rassf1a-/- (the murine gene) mice averaged 5.9 versus 9.1 for control mice (P < 0.01). Zn supplementation reduced tumor burdens by 28% (wild-type) to 42% (Fhit-/-Nit1-/-). Histological analysis of forestomach tissues also showed significant decreases in severity of preneoplastic and neoplastic lesions in Zn-supplemented cohorts of each mouse strain. Thus, Zn supplementation significantly reduced tumor burdens in mice with multiple tumor suppressor deficiencies. When Zn supplementation was begun at 7 weeks after the final carcinogen dose, the reduction in tumor burden was the same as observed when supplementation began immediately after carcinogen dosing, suggesting that Zn supplementation may affect tumor progression rather than tumor initiation.

  3. 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.

  4. Functional Analysis of In-frame Indel ARID1A Mutations Reveals New Regulatory Mechanisms of Its Tumor Suppressor Functions

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    Bin Guan

    2012-10-01

    Full Text Available AT-rich interactive domain 1A (ARID1A has emerged as a new tumor suppressor in which frequent somatic mutations have been identified in several types of human cancers. Although most ARID1A somatic mutations are frame-shift or nonsense mutations that contribute to mRNA decay and loss of protein expression, 5% of ARID1A mutations are in-frame insertions or deletions (indels that involve only a small stretch of peptides. Naturally occurring in-frame indel mutations provide unique and useful models to explore the biology and regulatory role of ARID1A. In this study, we analyzed indel mutations identified in gynecological cancers to determine how these mutations affect the tumor suppressor function of ARID1A. Our results demonstrate that all in-frame mutants analyzed lost their ability to inhibit cellular proliferation or activate transcription of CDKN1A, which encodes p21, a downstream effector of ARID1A. We also showed that ARID1A is a nucleocytoplasmic protein whose stability depends on its subcellular localization. Nuclear ARID1A is less stable than cytoplasmic ARID1A because ARID1A is rapidly degraded by the ubiquitin-proteasome system in the nucleus. In-frame deletions affecting the consensus nuclear export signal reduce steady-state protein levels of ARID1A. This defect in nuclear exportation leads to nuclear retention and subsequent degradation. Our findings delineate a mechanism underlying the regulation of ARID1A subcellular distribution and protein stability and suggest that targeting the nuclear ubiquitin-proteasome system can increase the amount of the ARID1A protein in the nucleus and restore its tumor suppressor functions.

  5. A Catalog of Genes Homozygously Deleted in Human Lung Cancer and the Candidacy of PTPRD as a Tumor Suppressor Gene

    Science.gov (United States)

    Kohno, Takashi; Otsuka, Ayaka; Girard, Luc; Sato, Masanori; Iwakawa, Reika; Ogiwara, Hideaki; Sanchez-Cespedes, Montse; Minna, John D.; Yokota, Jun

    2010-01-01

    A total of 176 genes homozygously deleted in human lung cancer were identified by DNA array-based whole genome scanning of 52 lung cancer cell lines and subsequent genomic PCR in 74 cell lines, including the 52 cell lines scanned. One or more exons of these genes were homozygously deleted in one (1%) to 20 (27%) cell lines. These genes included known tumor suppressor genes, e.g., CDKN2A/p16, RB1, and SMAD4, and candidate tumor suppressor genes whose hemizygous or homozygous deletions were reported in several types of human cancers, such as FHIT, KEAP1, and LRP1B/LRP-DIP. CDKN2A/p16 and p14ARF located in 9p21 were most frequently deleted (20/74, 27%). The PTPRD gene was most frequently deleted (8/74, 11%) among genes mapping to regions other than 9p21. Somatic mutations, including a nonsense mutation, of the PTPRD gene were detected in 8/74 (11%) of cell lines and 4/95 (4%) of surgical specimens of lung cancer. Reduced PTPRD expression was observed in the majority (>80%) of cell lines and surgical specimens of lung cancer. Therefore, PTPRD is a candidate tumor suppressor gene in lung cancer. Microarray-based expression profiling of 19 lung cancer cell lines also indicated that some of the 176 genes, such as KANK and ADAMTS1, are preferentially inactivated by epigenetic alterations. Genetic/epigenetic as well as functional studies of these 176 genes will increase our understanding of molecular mechanisms behind lung carcinogenesis. PMID:20073072

  6. Functional expression of NF1 tumor suppressor protein: association with keratin intermediate filaments during the early development of human epidermis

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    Peltonen Sirkku

    2002-08-01

    Full Text Available Abstract Background NF1 refers to type 1 neurofibromatosis syndrome, which has been linked with mutations of the large NF1 gene. NF1 tumor suppressor protein, neurofibromin, has been shown to regulate ras: the NF1 protein contains a GTPase activating protein (GAP related domain which functions as p21rasGAP. Our studies have previously demonstrated that the NF1 protein forms a high affinity association with cytokeratin 14 during the formation of desmosomes and hemidesmosomes in cultured keratinocytes. Methods The expression of NF1 protein was studied in developing human epidermis using western transfer analysis, indirect immunofluorescence, confocal laser scanning microscopy, immunoelectron microscopy, and in situ hybridization. Results The expression of NF1 protein was noted to be highly elevated in the periderm at 8 weeks estimated gestational age (EGA and in the basal cells at 8–14 weeks EGA. During this period, NF1 protein was associated with cytokeratin filaments terminating to desmosomes and hemidesmosomes. NF1 protein did not display colocalization with α-tubulin or actin of the cytoskeleton, or with adherens junction proteins. Conclusions These results depict an early fetal period when the NF1 tumor suppressor is abundantly expressed in epidermis and associated with cytokeratin filaments. This period is characterized by the initiation of differentiation of the basal cells, maturation of the basement membrane zone as well as accentuated formation of selected cellular junctions. NF1 tumor suppressor may function in the regulation of epidermal histogenesis via controlling the organization of the keratin cytoskeleton during the assembly of desmosomes and hemidesmosomes.

  7. MiR-23a Functions as a Tumor Suppressor in Osteosarcoma

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    Yu He

    2014-10-01

    Full Text Available Background: Osteosarcoma is the most common primary bone malignancy in children and adolescents, and the pathogenesis of this cancer remains unclear. Therefore, the discovery of new biomarkers for the diagnosis, prognosis, and treatment of osteosarcoma remains an important but unmet clinical need. Method: Quantitative real-time PCR was carried out to examine the expression of miR-23a. Methylation-specific PCR was performed to evaluate the DNA methylation status of the miR-23a promoter. Cell proliferation, migration, and invasion were examined by cell counting assays, wound healing assays, and cell invasion assays, respectively. Western blot analysis and luciferase reporter assays were performed to identify miR-23 target genes. Nude mice were used to investigate the function of miR-23a in vivo. Results: The expression of miR-23a was decreased in osteosarcoma cells and tissues compared to normal controls. The promoter region of the miR-23a gene was hypermethylated in osteosarcoma cells, and demethylase treatment increased the expression of miR-23a. The ectopic expression of miR-23a led to retarded proliferation, migration, and invasion of osteosarcoma cells, whereas the depletion of miR-23a resulted in the opposite effects. MiR-23a suppressed the transcription of RUNX2 and CXCL12 by binding to the 3' UTRs of these mRNAs. The cellular function of miR-23a is RUNX2/CXCL12-dependent, and the overexpression of RUNX2 or CXCL12 rescued the impaired cell growth, migration, and invasion induced by miR-23a. Nude mouse experiments indicated that miR-23a may inhibit the proliferation of osteosarcoma cells in vivo. Conclusion: We identified miR-23a as a tumor suppressor in osteosarcoma. Our data clarify the mechanism of osteosarcoma progression and demonstrated the potential for exploiting miR-23a as a diagnostic marker for osteosarcoma.

  8. Complement C1q activates tumor suppressor WWOX to induce apoptosis in prostate cancer cells.

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    Qunying Hong

    Full Text Available BACKGROUND: Tissue exudates contain low levels of serum complement proteins, and their regulatory effects on prostate cancer progression are largely unknown. We examined specific serum complement components in coordinating the activation of tumor suppressors p53 and WWOX (also named FOR or WOX1 and kinases ERK, JNK1 and STAT3 in human prostate DU145 cells. METHODOLOGY/PRINCIPAL FINDINGS: DU145 cells were cultured overnight in 1% normal human serum, or in human serum depleted of an indicated complement protein. Under complement C1q- or C6-free conditions, WOX1 and ERK were mainly present in the cytoplasm without phosphorylation, whereas phosphorylated JNK1 was greatly accumulated in the nuclei. Exogenous C1q rapidly restored the WOX1 activation (with Tyr33 phosphorylation in less than 2 hr. Without serum complement C9, p53 became activated, and hyaluronan (HA reversed the effect. Under C6-free conditions, HA induced activation of STAT3, an enhancer of metastasis. Notably, exogenous C1q significantly induced apoptosis of WOX1-overexpressing DU145 cells, but not vehicle-expressing cells. A dominant negative and Y33R mutant of WOX1 blocked the apoptotic effect. C1q did not enhance p53-mediated apoptosis. By total internal reflection fluorescence (TIRF microscopy, it was determined that C1q destabilized adherence of WOX1-expressing DU145 cells by partial detaching and inducing formation of clustered microvilli for focal adhesion particularly in between cells. These cells then underwent shrinkage, membrane blebbing and death. Remarkably, as determined by immunostaining, benign prostatic hyperplasia and prostate cancer were shown to have a significantly reduced expression of tissue C1q, compared to age-matched normal prostate tissues. CONCLUSIONS/SIGNIFICANCE: We conclude that complement C1q may induce apoptosis of prostate cancer cells by activating WOX1 and destabilizing cell adhesion. Downregulation of C1q enhances prostate hyperplasia and cancerous

  9. The expression of a tumor suppressor gene JDP2 and its prognostic value in hepatocellular carcinoma patients.

    Science.gov (United States)

    Chen, Yao-Li; Chan, Shih-Hsuan; Lin, Ping-Yi; Chu, Pei-Yi

    2017-05-01

    The c-Jun dimerization protein 2 (JDP2) belongs to the activator protein-1 (AP-1) family and functions as a repressor of the AP-1 complex by dimerizing with other c-Jun proteins. Thus, JDP2 plays an important role in the repression of AP-1-driven biological processes, such as differentiation and proliferation. Recent studies have suggested that JDP2 may function as a tumor suppressor through its suppressive action against the AP-1 complex, which is known to drive oncogenic signals in several human malignancies. In this study, we used immunohistochemistry to examine the JDP2 expression in 211 cases of hepatocellular carcinoma (HCC) and analyzed the potential link of JDP2 expression to the clinicopathological features of HCC patients. Clinical parameter analysis showed that high expression of JDP2 was significantly correlated with smaller tumor size (P=.002) and early stage HCC (P=.039). Moreover, Kaplan-Meier survival analysis showed that high expression of JDP2 was significantly associated with better survival in HCC patients (P=.006). Taken together, our results showed that JDP2 may serve as a tumor suppressor in HCC and could therefore serve as a good prognostic marker for patients with HCC. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. 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.

  11. Mathematical modeling of tumor-induced immunosuppression by myeloid-derived suppressor cells: Implications for therapeutic targeting strategies.

    Science.gov (United States)

    Shariatpanahi, Seyed Peyman; Shariatpanahi, Seyed Pooya; Madjidzadeh, Keivan; Hassan, Moustapha; Abedi-Valugerdi, Manuchehr

    2018-04-07

    Myeloid-derived suppressor cells (MDSCs) belong to immature myeloid cells that are generated and accumulated during the tumor development. MDSCs strongly suppress the anti-tumor immunity and provide conditions for tumor progression and metastasis. In this study, we present a mathematical model based on ordinary differential equations (ODE) to describe tumor-induced immunosuppression caused by MDSCs. The model consists of four equations and incorporates tumor cells, cytotoxic T cells (CTLs), natural killer (NK) cells and MDSCs. We also provide simulation models that evaluate or predict the effects of anti-MDSC drugs (e.g., l-arginine and 5-Fluorouracil (5-FU)) on the tumor growth and the restoration of anti-tumor immunity. The simulated results obtained using our model were in good agreement with the corresponding experimental findings on the expansion of splenic MDSCs, immunosuppressive effects of these cells at the tumor site and effectiveness of l-arginine and 5-FU on the re-establishment of antitumor immunity. Regarding this latter issue, our predictive simulation results demonstrated that intermittent therapy with low-dose 5-FU alone could eradicate the tumors irrespective of their origins and types. Furthermore, at the time of tumor eradication, the number of CTLs prevailed over that of cancer cells and the number of splenic MDSCs returned to the normal levels. Finally, our predictive simulation results also showed that the addition of l-arginine supplementation to the intermittent 5-FU therapy reduced the time of the tumor eradication and the number of iterations for 5-FU treatment. Thus, the present mathematical model provides important implications for designing new therapeutic strategies that aim to restore antitumor immunity by targeting MDSCs. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. SIGNALING TO THE P53 TUMOR SUPPRESSOR THROUGH PATHWAYS ACTIVATED BY GENOTOXIC AND NON-GENOTOXIC STRESSES.

    Energy Technology Data Exchange (ETDEWEB)

    ANDERSON,C.W.APPELLA,E.

    2002-07-01

    The p53 tumor suppressor is a tetrameric transcription factor that is post-translational modified at {approx}18 different sites by phosphorylation, acetylation, or sumoylation in response to various cellular stress conditions. Specific posttranslational modifications, or groups of modifications, that result from the activation of different stress-induced signaling pathways are thought to modulate p53 activity to regulate cell fate by inducing cell cycle arrest, apoptosis, or cellular senescence. Here we review the posttranslational modifications to p53 and the pathways that produce them in response to both genotoxic and non-genotoxic stresses.

  13. Cylindromatosis Tumor Suppressor Protein (CYLD) Deubiquitinase is Necessary for Proper Ubiquitination and Degradation of the Epidermal Growth Factor Receptor

    DEFF Research Database (Denmark)

    Sanchez-Quiles, Virginia; Akimov, Vyacheslav; Osinalde, Nerea

    2017-01-01

    Cylindromatosis tumor suppressor protein (CYLD) is a deubiquitinase, best known as an essential negative regulator of the NFkB pathway. Previous studies have suggested an involvement of CYLD in epidermal growth factor (EGF)-dependent signal transduction as well, as it was found enriched within...... spectrometry-based quantitative proteomic approaches with biochemical and immunofluorescence strategies, we demonstrate the involvement of CYLD in the regulation of the ubiquitination events triggered by EGF. Our data show that CYLD regulates the magnitude of ubiquitination of several major effectors...

  14. Grape seed proanthocyanidins reactivate silenced tumor suppressor genes in human skin cancer cells by targeting epigenetic regulators

    Energy Technology Data Exchange (ETDEWEB)

    Vaid, Mudit; Prasad, Ram; Singh, Tripti; Jones, Virginia [Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL 35294 (United States); Katiyar, Santosh K., E-mail: skatiyar@uab.edu [Birmingham Veterans Affairs Medical Center, Birmingham, AL 35294 (United States); Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL 35294 (United States); Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL 35294 (United States)

    2012-08-15

    Grape seed proanthocyanidins (GSPs) have been shown to have anti-skin carcinogenic effects in in vitro and in vivo models. However, the precise epigenetic molecular mechanisms remain unexplored. This study was designed to investigate whether GSPs reactivate silenced tumor suppressor genes following epigenetic modifications in skin cancer cells. For this purpose, A431 and SCC13 human squamous cell carcinoma cell lines were used as in vitro models. The effects of GSPs on DNA methylation, histone modifications and tumor suppressor gene expressions were studied in these cell lines using enzyme activity assays, western blotting, dot-blot analysis and real-time polymerase chain reaction (RT-PCR). We found that treatment of A431 and SCC13 cells with GSPs decreased the levels of: (i) global DNA methylation, (ii) 5-methylcytosine, (iii) DNA methyltransferase (DNMT) activity and (iv) messenger RNA (mRNA) and protein levels of DNMT1, DNMT3a and DNMT3b in these cells. Similar effects were noted when these cancer cells were treated identically with 5-aza-2′-deoxycytidine, an inhibitor of DNA methylation. GSPs decreased histone deacetylase activity, increased levels of acetylated lysines 9 and 14 on histone H3 (H3-Lys 9 and 14) and acetylated lysines 5, 12 and 16 on histone H4, and reduced the levels of methylated H3-Lys 9. Further, GSP treatment resulted in re-expression of the mRNA and proteins of silenced tumor suppressor genes, RASSF1A, p16{sup INK4a} and Cip1/p21. Together, this study provides a new insight into the epigenetic mechanisms of GSPs and may have significant implications for epigenetic therapy in the treatment/prevention of skin cancers in humans. -- Highlights: ►Epigenetic modulations have been shown to have a role in cancer risk. ►Proanthocyanidins decrease the levels of DNA methylation and histone deacetylation. ►Proanthocyanidins inhibit histone deacetylase activity in skin cancer cells. ►Proanthocyanidins reactivate tumor suppressor genes in skin

  15. Lack of mutations in the TP53 tumor suppressor gene exons 5 to 8 in Fanconi's anemia.

    Science.gov (United States)

    Jonveaux, P; Le Coniat, M; Grausz, D; Berger, R

    1991-01-01

    The TP53 gene is considered to be a negative regulator of cell growth whose inactivation is an important step in the development or progression of malignancies. Recently, germ line TP53 mutations have been detected in a familial cancer syndrome, the dominantly inherited Li-Fraumeni syndrome. Using single strand conformation polymorphism analysis of PCR products, we looked for TP53 mutations in DNA of patients with Fanconi anemia, an autosomal recessive disease characterized by increased predisposition to neoplasia. We did not find any TP53 mutation in 13 patients, suggesting that this tumor suppressor gene is not directly involved in the cancer susceptibility observed in Fanconi's anemia.

  16. MicroRNA-31 functions as an oncogenic microRNA in mouse and human lung cancer cells by repressing specific tumor suppressors

    DEFF Research Database (Denmark)

    Liu, Xi; Sempere, Lorenzo F; Ouyang, Haoxu

    2010-01-01

    confirmed them as direct targets in human and mouse lung cancer cell lines. These targets included the tumor-suppressive genes large tumor suppressor 2 (LATS2) and PP2A regulatory subunit B alpha isoform (PPP2R2A), and expression of each was augmented by miR-31 knockdown. Their engineered repression...

  17. The wip1 phosphatase (PPM1D) antagonizes activation of the CHK2 tumor suppressor kinase

    Energy Technology Data Exchange (ETDEWEB)

    Manet, Oliva-Trastoy; Berthonaud, V.; Chevalier, A.; Ducrot, C.; Marsolier-Kergoat, M.C.; Mann, C.; Leteurtre, F. [CEA Saclay, DSV, DBJC, SBGM, Lab. du Controle du Cycle Cellulaire, 91 - Gif-sur-Yvette (France)

    2006-07-01

    The DNA checkpoints are signal transduction pathways that sense DNA damage and coordinate various responses such as cell cycle arrests, DNA repair or cell death. These pathways are particularly well conserved in eukaryotes and the family of the 'Checkpoint Kinases 2' genes (or CHK2) plays a major role in them. This family includes the Rad53 protein of the yeast Saccharomyces cerevisiae and its Chk2 human homologue. Rad53 plays a central part in DNA checkpoint: rad53d mutants (whose RAD53 gene has been deleted) are hypersensitive to all genotoxic stresses. Mice Chk2-1- cells are defective in the G1, the intra-S, and the G2/M checkpoints. Mutations in CHK2 have been associated to many forms o f cancer, either sporadic or hereditary which demonstrates Chk2 tumor suppressor function. Chk2 proteins are characterized by several conserved elements: (i) an N-terminal domain with a series of SQ/TQ motifs, preferential phosphorylation sites for the ATM/ATR kinases, (ii) an FHA domain (ForkHead Associated) that binds specifically to phosphorylated residues within TXXY motifs (with the Y residue depending on the FHA domain and conferring an extra specificity) and (iii) a kinase domain including an activation loop. The Chk2 protein is activated by phosphorylation of its threonine T68, mainly by ATM, upon DNA double-strand breaks. This phosphorylation allows for the homo-dimerization of Chk2 through the binding of phospho-T68 from one molecule to the FHA domain of another molecule. It results in trans auto-phosphorylations, especially at threonines T383 and T387 in the activation T-loop. Fully active Chk2 becomes monomeric and, diffusing through the whole nucleus, phosphorylates its targets (CDC25 A and CDC25C/cell cycle arrest; p53, E2F, PML/apoptosis; BRCA2/DNA repair). Chk2/Rad53 inactivation occurs in two cases: once the DNA lesions have been repaired (it is called recovery) or, under certain conditions, in the presence of unrepaired DNA damage (it is then called

  18. Cancer cell specific cytotoxic gene expression mediated by ARF tumor suppressor promoter constructs

    Energy Technology Data Exchange (ETDEWEB)

    Kurayoshi, Kenta [Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337 (Japan); Ozono, Eiko [Centre for Molecular Oncology, Barts Cancer Institute, Queen Mary, University of London, John Vane Science Centre, Charterhouse Square, London EC1M 6BQ (United Kingdom); Iwanaga, Ritsuko; Bradford, Andrew P. [Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Anschutz Medical Campus, 12800 East 19th Avenue, Aurora, CO 80045 (United States); Komori, Hideyuki [Center for Stem Cell Biology, Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109 (United States); Ohtani, Kiyoshi, E-mail: btm88939@kwansei.ac.jp [Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337 (Japan)

    2014-07-18

    Highlights: • ARF promoter showed higher responsiveness to deregulated E2F activity than the E2F1 promoter. • ARF promoter showed higher cancer cell-specificity than E2F1 promoter to drive gene expression. • HSV-TK driven by ARF promoter showed higher cancer cell-specific cytotoxicity than that driven by E2F1 promoter. - Abstract: In current cancer treatment protocols, such as radiation and chemotherapy, side effects on normal cells are major obstacles to radical therapy. To avoid these side effects, a cancer cell-specific approach is needed. One way to specifically target cancer cells is to utilize a cancer specific promoter to express a cytotoxic gene (suicide gene therapy) or a viral gene required for viral replication (oncolytic virotherapy). For this purpose, the selected promoter should have minimal activity in normal cells to avoid side effects, and high activity in a wide variety of cancers to obtain optimal therapeutic efficacy. In contrast to the AFP, CEA and PSA promoters, which have high activity only in a limited spectrum of tumors, the E2F1 promoter exhibits high activity in wide variety of cancers. This is based on the mechanism of carcinogenesis. Defects in the RB pathway and activation of the transcription factor E2F, the main target of the RB pathway, are observed in almost all cancers. Consequently, the E2F1 promoter, which is mainly regulated by E2F, has high activity in wide variety of cancers. However, E2F is also activated by growth stimulation in normal growing cells, suggesting that the E2F1 promoter may also be highly active in normal growing cells. In contrast, we found that the tumor suppressor ARF promoter is activated by deregulated E2F activity, induced by forced inactivation of pRB, but does not respond to physiological E2F activity induced by growth stimulation. We also found that the deregulated E2F activity, which activates the ARF promoter, is detected only in cancer cell lines. These observations suggest that ARF promoter

  19. The telomerase inhibitor PinX1 is a major haploinsufficient tumor suppressor essential for chromosome stability in mice.

    Science.gov (United States)

    Zhou, Xiao Zhen; Huang, Pengyu; Shi, Rong; Lee, Tae Ho; Lu, Gina; Zhang, Zhihong; Bronson, Roderick; Lu, Kun Ping

    2011-04-01

    Telomerase is activated in most human cancers and is critical for cancer cell growth. However, little is known about the significance of telomerase activation in chromosome instability and cancer initiation. The gene encoding the potent endogenous telomerase inhibitor PinX1 (PIN2/TRF1-interacting, telomerase inhibitor 1) is located at human chromosome 8p23, a region frequently exhibiting heterozygosity in many common human cancers, but the function or functions of PinX1 in development and tumorigenesis are unknown. Here we have shown that PinX1 is a haploinsufficient tumor suppressor essential for chromosome stability in mice. We found that PinX1 expression was reduced in most human breast cancer tissues and cell lines. Furthermore, PinX1 heterozygosity and PinX1 knockdown in mouse embryonic fibroblasts activated telomerase and led to concomitant telomerase-dependent chromosomal instability. Moreover, while PinX1-null mice were embryonic lethal, most PinX1+/- mice spontaneously developed malignant tumors with evidence of chromosome instability. Notably, most PinX1 mutant tumors were carcinomas and shared tissues of origin with human cancer types linked to 8p23. PinX1 knockout also shifted the tumor spectrum of p53 mutant mice from lymphoma toward epithelial carcinomas. Thus, PinX1 is a major haploinsufficient tumor suppressor essential for maintaining telomerase activity and chromosome stability. These findings uncover what we believe to be a novel role for PinX1 and telomerase in chromosome instability and cancer initiation and suggest that telomerase inhibition may be potentially used to treat cancers that overexpress telomerase.

  20. Metastasis Suppressor Gene Inactivates Actin-Based Mechanism of Tumor Cell Motility | Center for Cancer Research

    Science.gov (United States)

    Metastasis is responsible for up to 90 percent of all cancer-related deaths. Though proteins derived from nearly a dozen metastasis suppressor genes have been discovered over the past 15 years, strategies for exploiting the proteins in metastasis-prevention therapies has been hampered by the lack of knowledge regarding the mechanisms underlying the proteins’ interactions with other proteins.

  1. ABERRANT SPLICING OF A BRAIN-ENRICHED ALTERNATIVE EXON ELIMINATES TUMOR SUPPRESSOR FUNCTION AND PROMOTES ONCOGENE FUNCTION DURING BRAIN TUMORIGENESIS

    Science.gov (United States)

    Bredel, Markus; Ferrarese, Roberto; Harsh, Griffith R.; Yadav, Ajay K.; Bug, Eva; Maticzka, Daniel; Reichardt, Wilfried; Masilamani, Anie P.; Dai, Fangping; Kim, Hyunsoo; Hadler, Michael; Scholtens, Denise M.; Yu, Irene L.Y.; Beck, Jürgen; Srinivasasainagendra, Vinodh; Costa, Fabrizio; Baxan, Nicoleta; Pfeifer, Dietmar; Elverfeldt, Dominik v.; Backofen, Rolf; Weyerbrock, Astrid; Duarte, Christine W.; He, Xiaolin; Prinz, Marco; Chandler, James P.; Vogel, Hannes; Chakravarti, Arnab; Rich, Jeremy N.; Carro, Maria S.

    2014-01-01

    BACKGROUND: Tissue-specific alternative splicing is known to be critical to emergence of tissue identity during development, yet its role in malignant transformation is undefined. Tissue-specific splicing involves evolutionary-conserved, alternative exons, which represent only a minority of total alternative exons. Many, however, have functional features that influence activity in signaling pathways to profound biological effect. Given that tissue-specific splicing has a determinative role in brain development and the enrichment of genes containing tissue-specific exons for proteins with roles in signaling and development, it is thus plausible that changes in such exons could rewire normal neurogenesis towards malignant transformation. METHODS: We used integrated molecular genetic and cell biology analyses, computational biology, animal modeling, and clinical patient profiles to characterize the effect of aberrant splicing of a brain-enriched alternative exon in the membrane-binding tumor suppressor Annexin A7 (ANXA7) on oncogene regulation and brain tumorigenesis. RESULTS: We show that aberrant splicing of a tissue-specific cassette exon in ANXA7 diminishes endosomal targeting and consequent termination of the signal of the EGFR oncoprotein during brain tumorigenesis. Splicing of this exon is mediated by the ribonucleoprotein Polypyrimidine Tract-Binding Protein 1 (PTBP1), which is normally repressed during brain development but, we find, is excessively expressed in glioblastomas through either gene amplification or loss of a neuron-specific microRNA, miR-124. Silencing of PTBP1 attenuates both malignancy and angiogenesis in a stem cell-derived glioblastoma animal model characterized by a high native propensity to generate tumor endothelium or vascular pericytes to support tumor growth. We show that EGFR amplification and PTBP1 overexpression portend a similarly poor clinical outcome, further highlighting the importance of PTBP1-mediated activation of EGFR

  2. CONVERGENCE OF P53 AND TGFβ SIGNALING ON ACTIVATING EXPRESSION OF THE TUMOR SUPPRESSOR GENE MASPIN IN MAMMARY EPITHELIAL CELLS

    Science.gov (United States)

    Wang, Shizhen Emily; Narasanna, Archana; Whitell, Corbin W.; Wu, Frederick Y.; Friedman, David B.; Arteaga, Carlos L.

    2014-01-01

    Using two-dimensional difference gel electrophoresis, we identified the tumor suppressor gene maspin as a TGFβ target gene in human mammary epithelial cells. TGFβ upregulates maspin expression both at the RNA and protein levels. This upregulation required Smad2/3 function and intact p53 binding elements in the maspin promoter. DNA affinity immunoblot and chromatin immunoprecipitation (ChIP) revealed the presence of both Smads and p53 at the maspin promoter in TGFβ-treated cells, suggesting that both transcription factors cooperate to induce maspin transcription. TGFβ did not activate maspin-luciferase reporter in p53-mutant MDA-MB-231 breast cancer cells, which exhibit methylation of the endogenous maspin promoter. Expression of ectopic p53, however, restored ligand-induced association of Smad2/3 with a transfected maspin promoter. Stable transfection of maspin inhibited basal and TGFβ-stimulated MDA-MB-231 cell motility. Finally, knockdown of endogenous maspin in p53 wild-type MCF10A/HER2 cells enhanced basal and TGFβ-stimulated motility. Taken together, these data support cooperation between the p53 and TGFβ tumor suppressor pathways in the induction of maspin expression, thus leading to inhibition of cell migration. PMID:17204482

  3. A defined chromosome 6q fragment (at D6S310) harbors a putative tumor suppressor gene for breast cancer.

    Science.gov (United States)

    Theile, M; Seitz, S; Arnold, W; Jandrig, B; Frege, R; Schlag, P M; Haensch, W; Guski, H; Winzer, K J; Barrett, J C; Scherneck, S

    1996-08-15

    Recent evidence obtained by cytogenetic and molecular studies indicates that in breast cancer chromosome 6q is often affected by genetic changes suggesting the existence of putative tumor suppressor genes (TSGs). However the function of gene(s) on this chromosome in breast cancer suppression is not understood. To substantiate further the presence of breast cancer related TSGs at 6q and to define their location, we first performed microcell-mediated transfer of chromosome 6 to CAL51 breast cancer cells for studying possible suppression of malignant phenotype and secondly, we analysed DNAs from 46 primary breast cancers for loss of constitutive heterozygosity (LOH) using 24 poly-morphic microsatellite markers. The chromosome transfer resulted in loss of tumorigenicity and reversion of other neoplastic properties of the microcell hybrids. Polymorphism analysis of single hybrids revealed that they harbored only a small donor chromosome fragment defined by the marker D6S310 (6q23.3-q25) and flanked by D6S292 and D6S311. The LOH data suggest that four tumor suppressor gene loci mapped to the central and distal portion of 6q may be independently deleted in breast cancer. One of these regions corresponds to the region identified by chromosome transfer.

  4. ERK5/BMK1 Is a Novel Target of the Tumor Suppressor VHL: Implication in Clear Cell Renal Carcinoma12

    Science.gov (United States)

    Arias-González, Laura; Moreno-Gimeno, Inmaculada; del Campo, Antonio Rubio; Serrano-Oviedo, Leticia; Valero, María Llanos; Esparís-Ogando, Azucena; de la Cruz-Morcillo, Miguel Ángel; Melgar-Rojas, Pedro; García-Cano, Jesús; Cimas, Francisco José; Hidalgo, María José Ruiz; Prado, Alfonso; Callejas-Valera, Juan Luis; Nam-Cha, Syong Hyun; Giménez-Bachs, José Miguel; Salinas-Sánchez, Antonio S; Pandiella, Atanasio; del Peso, Luis; Sánchez-Prieto, Ricardo

    2013-01-01

    Extracellular signal-regulated kinase 5 (ERK5), also known as big mitogen-activated protein kinase (MAPK) 1, is implicated in a wide range of biologic processes, which include proliferation or vascularization. Here, we show that ERK5 is degraded through the ubiquitin-proteasome system, in a process mediated by the tumor suppressor von Hippel-Lindau (VHL) gene, through a prolyl hydroxylation-dependent mechanism. Our conclusions derive from transient transfection assays in Cos7 cells, as well as the study of endogenous ERK5 in different experimental systems such as MCF7, HMEC, or Caki-2 cell lines. In fact, the specific knockdown of ERK5 in pVHL-negative cell lines promotes a decrease in proliferation and migration, supporting the role of this MAPK in cellular transformation. Furthermore, in a short series of fresh samples from human clear cell renal cell carcinoma, high levels of ERK5 correlate with more aggressive and metastatic stages of the disease. Therefore, our results provide new biochemical data suggesting that ERK5 is a novel target of the tumor suppressor VHL, opening a new field of research on the role of ERK5 in renal carcinomas. PMID:23730213

  5. Genomic analysis of follicular dendritic cell sarcoma by molecular inversion probe array reveals tumor suppressor-driven biology.

    Science.gov (United States)

    Andersen, Erica F; Paxton, Christian N; O'Malley, Dennis P; Louissaint, Abner; Hornick, Jason L; Griffin, Gabriel K; Fedoriw, Yuri; Kim, Young S; Weiss, Lawrence M; Perkins, Sherrie L; South, Sarah T

    2017-09-01

    Follicular dendritic cell sarcoma is a rare malignant neoplasm of dendritic cell origin that is currently poorly characterized by genetic studies. To investigate whether recurrent genomic alterations may underlie the biology of follicular dendritic cell sarcoma and to identify potential contributory regions and genes, molecular inversion probe array analysis was performed on 14 independent formalin-fixed, paraffin-embedded samples. Abnormal genomic profiles were observed in 11 out of 14 (79%) cases. The majority showed extensive genomic complexity that was predominantly represented by hemizygous losses affecting multiple chromosomes. Alterations of chromosomal regions 1p (55%), 2p (55%), 3p (82%), 3q (45%), 6q (55%), 7q (73%), 8p (45%), 9p (64%), 11q (64%), 13q (91%), 14q (82%), 15q (64%), 17p (55%), 18q (64%), and 22q (55%) were recurrent across the 11 samples showing abnormal genomic profiles. Many recurrent genomic alterations in follicular dendritic cell sarcoma overlap deletions that are frequently observed across human cancers, suggesting selection, or an active role for these alterations in follicular dendritic cell sarcoma pathogenesis. In support of a tumor suppressor-driven biology, homozygous deletions involving tumor suppressor genes CDKN2A, RB1, BIRC3, and CYLD were also observed. Neither recurrent gains nor amplifications were observed. This genomic characterization provides new information regarding follicular dendritic cell sarcoma biology that may improve understanding about the underlying pathophysiology, provide better prognostication, and identify potential therapeutic markers for this rare disease.

  6. ERK5/BMK1 Is a Novel Target of the Tumor Suppressor VHL: Implication in Clear Cell Renal Carcinoma

    Directory of Open Access Journals (Sweden)

    Laura Arias-González

    2013-06-01

    Full Text Available Extracellular signal-regulated kinase 5 (ERK5, also known as big mitogen-activated protein kinase (MAPK 1, is implicated in a wide range of biologic processes, which include proliferation or vascularization. Here, we show that ERK5 is degraded through the ubiquitin-proteasome system, in a process mediated by the tumor suppressor von Hippel-Lindau (VHL gene, through a prolyl hydroxylation-dependent mechanism. Our conclusions derive from transient transfection assays in Cos7 cells, as well as the study of endogenous ERK5 in different experimental systems such as MCF7, HMEC, or Caki-2 cell lines. In fact, the specific knockdown of ERK5 in pVHL-negative cell lines promotes a decrease in proliferation and migration, supporting the role of this MAPK in cellular transformation. Furthermore, in a short series of fresh samples from human clear cell renal cell carcinoma, high levels of ERK5 correlate with more aggressive and metastatic stages of the disease. Therefore, our results provide new biochemical data suggesting that ERK5 is a novel target of the tumor suppressor VHL, opening a new field of research on the role of ERK5 in renal carcinomas.

  7. Phytochemical Compositions of Immature Wheat Bran, and Its Antioxidant Capacity, Cell Growth Inhibition, and Apoptosis Induction through Tumor Suppressor Gene

    Directory of Open Access Journals (Sweden)

    Mi Jeong Kim

    2016-09-01

    Full Text Available The purpose of this study was to investigate the phytochemical compositions and antioxidant capacity, cell growth inhibition, and apoptosis induction in extracts of immature wheat bran. Immature wheat bran (IWB was obtained from immature wheat harvested 10 days earlier than mature wheat. The phytochemical compositions of bran extract samples were analyzed by ultra-high performance liquid chromatography. The total ferulic acid (3.09 mg/g and p-coumaric acid (75 µg/g in IWB were significantly higher than in mature wheat bran (MWB, ferulic acid: 1.79 mg/g; p-coumaric acid: 55 µg/g. The oxygen radical absorbance capacity (ORAC: 327 µM Trolox equivalents (TE/g and cellular antioxidant activity (CAA: 4.59 µM Quercetin equivalents (QE/g of the IWB were higher than those of the MWB (ORAC: 281 µM TE/g; CAA: 0.63 µM QE/g. When assessing cell proliferation, the IWB extracts resulted in the lowest EC50 values against HT-29 (18.9 mg/mL, Caco-2 (7.74 mg/mL, and HeLa cells (8.17 mg/mL among bran extract samples. Additionally, the IWB extracts increased the gene expression of p53 and PTEN (tumor suppressor genes in HT-29 cells, indicating inhibited cell growth and induced apoptosis through tumor suppressor genes.

  8. Phytochemical Compositions of Immature Wheat Bran, and Its Antioxidant Capacity, Cell Growth Inhibition, and Apoptosis Induction through Tumor Suppressor Gene.

    Science.gov (United States)

    Kim, Mi Jeong; Yoon, Won-Jin; Kim, Sang Sook

    2016-09-27

    The purpose of this study was to investigate the phytochemical compositions and antioxidant capacity, cell growth inhibition, and apoptosis induction in extracts of immature wheat bran. Immature wheat bran (IWB) was obtained from immature wheat harvested 10 days earlier than mature wheat. The phytochemical compositions of bran extract samples were analyzed by ultra-high performance liquid chromatography. The total ferulic acid (3.09 mg/g) and p -coumaric acid (75 µg/g) in IWB were significantly higher than in mature wheat bran (MWB, ferulic acid: 1.79 mg/g; p -coumaric acid: 55 µg/g). The oxygen radical absorbance capacity (ORAC: 327 µM Trolox equivalents (TE)/g) and cellular antioxidant activity (CAA: 4.59 µM Quercetin equivalents (QE)/g) of the IWB were higher than those of the MWB (ORAC: 281 µM TE/g; CAA: 0.63 µM QE/g). When assessing cell proliferation, the IWB extracts resulted in the lowest EC 50 values against HT-29 (18.9 mg/mL), Caco-2 (7.74 mg/mL), and HeLa cells (8.17 mg/mL) among bran extract samples. Additionally, the IWB extracts increased the gene expression of p53 and PTEN (tumor suppressor genes) in HT-29 cells, indicating inhibited cell growth and induced apoptosis through tumor suppressor genes.

  9. Investigational agent MLN9708/2238 targets tumor-suppressor miR33b in MM cells

    Science.gov (United States)

    Tian, Ze; Zhao, Jian-jun; Tai, Yu-Tzu; Amin, Samir B.; Hu, Yiguo; Berger, Allison J.; Richardson, Paul

    2012-01-01

    miRs play a critical role in tumor pathogenesis as either oncogenes or tumor-suppressor genes. However, the role of miRs and their regulation in response to proteasome inhibitors in multiple myeloma (MM) is unclear. In the current study, miR profiling in proteasome inhibitor MLN2238-treated MM.1S MM cells shows up-regulation of miR33b. Mechanistic studies indicate that the induction of miR33b is predominantly via transcriptional regulation. Examination of miR33b in patient MM cells showed a constitutively low expression. Overexpression of miR33b decreased MM cell viability, migration, colony formation, and increased apoptosis and sensitivity of MM cells to MLN2238 treatment. In addition, overexpression of miR33b or MLN2238 exposure negatively regulated oncogene PIM-1 and blocked PIM-1 wild-type, but not PIM-1 mutant, luciferase activity. Moreover, PIM-1 overexpression led to significant abrogation of miR33b- or MLN2238-induced cell death. SGI-1776, a biochemical inhibitor of PIM-1, triggered apoptosis in MM. Finally, overexpression of miR33b inhibited tumor growth and prolonged survival in both subcutaneous and disseminated human MM xenograft models. Our results show that miR33b is a tumor suppressor that plays a role during MLN2238-induced apoptotic signaling in MM cells, and these data provide the basis for novel therapeutic strategies targeting miR33b in MM. PMID:22983447

  10. Altered RNA editing in 3′ UTR perturbs microRNA-mediated regulation of oncogenes and tumor-suppressors

    Science.gov (United States)

    Zhang, Liye; Yang, Chih-Sheng; Varelas, Xaralabos; Monti, Stefano

    2016-01-01

    RNA editing is a molecular event that alters specific nucleotides in RNA post-transcriptionally. RNA editing has the potential to impact a variety of cellular processes and is implicated in diseases such as cancer. Yet, the precise mechanisms by which RNA editing controls cellular processes are poorly understood. Here, we characterize sequences altered by RNA editing in patient samples from lymphoma, neuroblastoma and head and neck cancers. We show that A-to-I RNA editing sites are highly conserved across samples of the same tissue type and that most editing sites identified in tumors are also detectable in normal tissues. Next, we identify the significant changes in editing levels of known sites between tumor and paired “normal” tissues across 14 cancer types (627 pairs) from The Cancer Genome Atlas project and show that the complexity of RNA editing regulation cannot be captured by the activity of ADAR family genes alone. Our pan-cancer analysis confirms previous results on individual tumor types and suggests that changes of RNA editing levels in coding and 3′UTR regions could be a general mechanism to promote tumor growth. We also propose a model explaining how altered RNA editing levels affect microRNA-mediated post-transcriptional regulation of oncogenes and tumor-suppressors. PMID:26980570

  11. Genistein inhibits proliferation of colon cancer cells by attenuating a negative effect of epidermal growth factor on tumor suppressor FOXO3 activity

    Directory of Open Access Journals (Sweden)

    Wasland Kaarin

    2011-06-01

    Full Text Available Abstract Background Soy consumption is associated with a lower incidence of colon cancer which is believed to be mediated by one of its of components, genistein. Genistein may inhibit cancer progression by inducing apoptosis or inhibiting proliferation, but mechanisms are not well understood. Epidermal growth factor (EGF-induced proliferation of colon cancer cells plays an important role in colon cancer progression and is mediated by loss of tumor suppressor FOXO3 activity. The aim of this study was to assess if genistein exerts anti-proliferative properties by attenuating the negative effect of EGF on FOXO3 activity. Methods The effect of genistein on proliferation stimulated by EGF-mediated loss of FOXO3 was examined in human colonic cancer HT-29 cells. EGF-induced FOXO3 phosphorylation and translocation were assessed in the presence of genistein. EGF-mediated loss of FOXO3 interactions with p53 (co-immunoprecipitation and promoter of p27kip1 (ChIP assay were examined in presence of genistein in cells with mutated p53 (HT-29 and wild type p53 (HCT116. Silencing of p53 determined activity of FOXO3 when it is bound to p53. Results Genistein inhibited EGF-induced proliferation, while favoring dephosphorylation and nuclear retention of FOXO3 (active state in colon cancer cells. Upstream of FOXO3, genistein acts via the PI3K/Akt pathway to inhibit EGF-stimulated FOXO3 phosphorylation (i.e. favors active state. Downstream, EGF-induced disassociation of FOXO3 from mutated tumor suppressor p53, but not wild type p53, is inhibited by genistein favoring FOXO3-p53(mut interactions with the promoter of the cell cycle inhibitor p27kip1 in colon cancer cells. Thus, the FOXO3-p53(mut complex leads to elevated p27kip1 expression and promotes cell cycle arrest. Conclusion These novel anti-proliferative mechanisms of genistein suggest a possible role of combining genistein with other chemoreceptive agents for the treatment of colon cancer.

  12. Hypermethylated in cancer 1 (HIC1), a tumor suppressor gene epigenetically deregulated in hyperparathyroid tumors by histone H3 lysine modification.

    Science.gov (United States)

    Svedlund, Jessica; Koskinen Edblom, Susanne; Marquez, Victor E; Åkerström, Göran; Björklund, Peyman; Westin, Gunnar

    2012-07-01

    Primary hyperparathyroidism (pHPT) resulting from parathyroid tumors is a common endocrine disorder with incompletely understood etiology. In renal failure, secondary hyperparathyroidism (sHPT) occurs with multiple tumor development as a result of calcium and vitamin D regulatory disturbance. The aim of the study was to investigate whether HIC1 may act as a tumor suppressor in the parathyroid glands and whether deregulated expression involves epigenetic mechanisms. Parathyroid tumors from patients with pHPT included single adenomas, multiple tumors from the same patient, and cancer. Hyperplastic parathyroid glands from patients with sHPT and hypercalcemia and normal parathyroid tissue specimens were included in the study. Quantitative RT-PCR, bisulfite pyrosequencing, colony formation assay, chromatin immunoprecipitation, and RNA interference was used. HIC1 was generally underexpressed regardless of the hyperparathyroid disease state including multiple parathyroid tumors from the same patient, and overexpression of HIC1 led to a decrease in clonogenic survival of parathyroid tumor cells. Only the carcinomas showed a high methylation level and reduced HIC1 expression. Cell culture experiments, including use of primary parathyroid tumor cells prepared directly after operation, the general histone methyltransferase inhibitor 3-deazaneplanocin A, chromatin immunoprecipitation, and RNA interference of DNA methyltransferases and EZH2 (enhancer of zeste homolog 2), supported a role of repressive histone H3 modifications (H3K27me2/3) rather than DNA methylation in repression of HIC1. The results strongly support a growth-regulatory role of HIC1 in the parathyroid glands and suggest that perturbed expression of HIC1 may represent an early event during tumor development. Repressive histone modification H3K27me2/3 is involved in repression of HIC1 expression in hyperparathyroid tumors.

  13. NEMO, a Transcriptional Target of Estrogen and Progesterone, Is Linked to Tumor Suppressor PML in Breast Cancer.

    Science.gov (United States)

    Elsarraj, Hanan S; Valdez, Kelli E; Hong, Yan; Grimm, Sandra L; Ricci, Lawrence R; Fan, Fang; Tawfik, Ossama; May, Lisa; Cusick, Therese; Inciardi, Marc; Redick, Mark; Gatewood, Jason; Winblad, Onalisa; Hilsenbeck, Susan; Edwards, Dean P; Hagan, Christy R; Godwin, Andrew K; Fabian, Carol; Behbod, Fariba

    2017-07-15

    The beneficial versus detrimental roles of estrogen plus progesterone (E+P) in breast cancer remains controversial. Here we report a beneficial mechanism of E+P treatment in breast cancer cells driven by transcriptional upregulation of the NFκB modulator NEMO, which in turn promotes expression of the tumor suppressor protein promyelocytic leukemia (PML). E+P treatment of patient-derived epithelial cells derived from ductal carcinoma in situ (DCIS) increased secretion of the proinflammatory cytokine IL6. Mechanistic investigations indicated that IL6 upregulation occurred as a result of transcriptional upregulation of NEMO, the gene that harbored estrogen receptor (ER) binding sites within its promoter. Accordingly, E+P treatment of breast cancer cells increased ER binding to the NEMO promoter, thereby increasing NEMO expression, NFκB activation, and IL6 secretion. In two mouse xenograft models of DCIS, we found that RNAi-mediated silencing of NEMO increased tumor invasion and progression. This seemingly paradoxical result was linked to NEMO-mediated regulation of NFκB and IL6 secretion, increased phosphorylation of STAT3 on Ser727, and increased expression of PML, a STAT3 transcriptional target. In identifying NEMO as a pivotal transcriptional target of E+P signaling in breast cancer cells, our work offers a mechanistic explanation for the paradoxical antitumorigenic roles of E+P in breast cancer by showing how it upregulates the tumor suppressor protein PML. Cancer Res; 77(14); 3802-13. ©2017 AACR. ©2017 American Association for Cancer Research.

  14. Wolf–Hirschhorn Syndrome Candidate 1 (whsc1 Functions as a Tumor Suppressor by Governing Cell Differentiation

    Directory of Open Access Journals (Sweden)

    Chuan Yu

    2017-08-01

    Full Text Available Wolf–Hirschhorn syndrome candidate 1 (WHSC1 is a histone 3 lysine 36 (H3K36 specific methyltransferase that is frequently deleted in Wolf–Hirschhorn syndrome (WHS. Whsc1 is also found mutated in a subgroup of B-cell derived malignant diseases by genomic translocation or point mutation, both of which resulted in hyperactivity of WHSC1 mediated H3K36 methylation and uncontrolled cell proliferation, suggesting that whsc1 functions as an oncogene. However, here we provided evidences to show that whsc1 also has tumor suppressor functions. We used zebrafish as an in vivo model and generated homozygous whsc1 mutant lines via clustered regularly interspaced short palindromic repeats-associated protein Cas9 (CRISPR/Cas9 technology. Then western-blot (WB and immunofluorescence (IF were performed to analysis the expression level of H3K36Me2 and H3K36Me3, and we identified the diseased tissue via hematoxylin–eosin (HE staining, IF staining or immunohistochemistry (IHC. Whsc1 lose-of-function led to significant decrease in di- and tri-methylation of H3K36. A series of WHS related phenotypes were found in whsc1−/− zebrafish, including growth retardation, neural development defects and heart failure. In addition, loss of function of whsc1 led to defects in the development of swim bladder, possibly through the dis-regulation of key genes in swim bladder organogenesis and inhibition of progenitor cell differentiation, which was correlated with its expression in this organ during embryonic development. At later stage, these whsc1−/− zebrafishes are inclined to grow tumors in the swim bladder. Our work suggested that whsc1 may function as a tumor suppressor by governing progenitor cell differentiation.

  15. TRIM26 functions as a novel tumor suppressor of hepatocellular carcinoma and its downregulation contributes to worse prognosis

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yi, E-mail: wangyichenben@163.com [Department of General Surgery, The Affiliated Baoan Hospital of Southern Medical University, Shenzhen, Guangdong, 518101 (China); He, Du, E-mail: hdu1234@163.com [Department of Oncology, The Central Hospital of Enshi Autonomous of Prefecture, Enshi Clinical College of Wuhan University, Enshi, Hubei, 445000 (China); Yang, Liang, E-mail: yliang0689@163.com [Department of Oncology, Qianjiang Central Hospital, Qianjiang, Hubei, 433100 (China); Wen, Bo, E-mail: tjwb001@126.com [Department of Urology, The Affiliated Baoan Hospital of Southern Medical University, Shenzhen, Guangdong, 518101 (China); Dai, Jinfen, E-mail: brilliant_510@126.com [Department of Gastroenterology, Renmin Hospital of Wuhan University, Wuhan, Hubei, 430060 (China); Zhang, Qian, E-mail: anny9655@126.com [Department of Immunology, School of Basic Medicine, Wuhan University, Wuhan, Hubei, 430071 (China); Kang, Jian, E-mail: 984190619@qq.com [Department of Gastroenterology, Renmin Hospital of Wuhan University, Wuhan, Hubei, 430060 (China); He, Weiyang, E-mail: 996114664@qq.com [Department of Immunology, School of Basic Medicine, Wuhan University, Wuhan, Hubei, 430071 (China); Ding, Qianshan, E-mail: iamdqs@163.com [Department of Gastroenterology, Renmin Hospital of Wuhan University, Wuhan, Hubei, 430060 (China); He, De, E-mail: 18938027146@126.com [Department of General Surgery, The Affiliated Baoan Hospital of Southern Medical University, Shenzhen, Guangdong, 518101 (China)

    2015-07-31

    Hepatocellular carcinoma (HCC) is the one of the most common malignancies worldwide and its prognosis is extremely poor. Tripartite motif (TRIM) proteins play crucial roles in cancer cell biology but the function of tripartite motif 26 (TRIM26) has not been investigated. We demonstrated that low expression level of TRIM26 in tumor samples was significantly correlated with worse prognosis in HCC patients. We also demonstrated its expression level was associated with several clinicopathologic features such as AFP level and T stage of HCC patients. Furthermore, we validated that TRIM26 was significantly downregulated in HCC tissue compared with normal liver tissue. To further clarify the functional role of TRIM26 in HCC, We confirmed that TRIM26 silencing can promote cancer cell proliferation, colony forming, migration and invasion in vitro with HCC cell lines HepG2 and Bel-7402. Then we utilized bioinformatic tool to predict gene influenced by TRIM26, showing TRIM26 could modulate gene sets about cancer cell metabolism. In conclusion, we proved that TRIM26 is a novel tumor suppressor modulating multiple metabolism-related pathways in HCC. To our best knowledge, this is the first study to investigate the function of TRIM26 in cancer biology. Our findings provide useful insight into the mechanism of HCC origin and progression. Moreover, TRIM26 may represent a novel therapeutic target for HCC. - Highlights: • TRIM26 is down-regulated in liver cancer samples and functions as a novel tumor suppressor. • Down-regulation of TRIM26 is associated with worse prognosis of hepatocellular carcinoma (HCC). • Knockdown of TRIM26 promotes the proliferation and metastasis of HCC cells. • TRIM26 may function in abnormal metabolic progress of HCC.

  16. Human umbilical cord matrix mesenchymal stem cells suppress the growth of breast cancer by expression of tumor suppressor genes.

    Directory of Open Access Journals (Sweden)

    Naomi Ohta

    Full Text Available Human and rat umbilical cord matrix mesenchymal stem cells (UCMSC possess the ability to control the growth of breast carcinoma cells. Comparative analyses of two types of UCMSC suggest that rat UCMSC-dependent growth regulation is significantly stronger than that of human UCMSC. Their different tumoricidal abilities were clarified by analyzing gene expression profiles in the two types of UCMSC. Microarray analysis revealed differential gene expression between untreated naïve UCMSC and those co-cultured with species-matched breast carcinoma cells. The analyses screened 17 differentially expressed genes that are commonly detected in both human and rat UCMSC. The comparison between the two sets of gene expression profiles identified two tumor suppressor genes, adipose-differentiation related protein (ADRP and follistatin (FST, that were specifically up-regulated in rat UCMSC, but down-regulated in human UCMSC when they were co-cultured with the corresponding species' breast carcinoma cells. Over-expression of FST, but not ADRP, in human UCMSC enhanced their ability to suppress the growth of MDA-231 cells. The growth of MDA-231 cells was also significantly lower when they were cultured in medium conditioned with FST, but not ADRP over-expressing human UCMSC. In the breast carcinoma lung metastasis model generated with MDA-231 cells, systemic treatment with FST-over-expressing human UCMSC significantly attenuated the tumor burden. These results suggest that FST may play an important role in exhibiting stronger tumoricidal ability in rat UCMSC than human UCMSC and also implies that human UCMSC can be transformed into stronger tumoricidal cells by enhancing tumor suppressor gene expression.

  17. Regulation of a senescence checkpoint response by the E2F1 transcription factor and p14ARF tumor suppressor

    Energy Technology Data Exchange (ETDEWEB)

    Dimri, Goberdhan P.; Itahana, Koji; Acosta, Meileen; Campisi, Judith

    1999-11-05

    Normal cells do not divide indefinitely due to a process known as replicative senescence. Human cells arrest growth with a senescent phenotype when they acquire one or more critically short telomere as a consequence of cell division. Recent evidence suggests that certain types of DNA damage, chromatin remodeling, or oncogenic forms of Rasor Raf can also elicit a senescence response. We show here that E2F1, a multifunctional transcription factor that binds the retinoblastoma (pRb) tumor suppressor and can either promote or suppress tumorigenesis, induces a senescent phenotype when overexpressed in normal human fibroblasts. Normal human cells stably arrested proliferation and expressed several markers of replicative senescence in response to E2F1. This activity of E2F1 was independent of its pRb binding activity, but dependent on its ability to stimulate gene expression. The E2F1 target gene critical for the senescence response appeared to be the p14ARF tumor suppressor. Replicatively senescent human fibroblasts overexpressed p14ARF, and ectopic expression of p14ARF in presenescent cells induced a phenotype similar to that induced by E2F1. Consistent with a critical role for p14ARF, cells with compromised p53 function were immune to senescence induction by E2F1, as were cells deficient in p14ARF. Our findings support the idea that the senescence response is a critical tumor suppressive mechanism, provide an explanation for the apparently paradoxical roles of E2F1 in oncogenesis, and identify p14ARF as a potentially important mediator of the senescent phenotype.

  18. Amplexicaule A exerts anti-tumor effects by inducing apoptosis in human breast cancer

    OpenAIRE

    Xiang, Meixian; Su, Hanwen; Shu, Guangwen; Wan, Dingrong; He, Feng; Loaec, Morgann; Ding, Yali; Li, Jun; Dovat, Sinisa; Yang, Gaungzhong; Song, Chunhua

    2016-01-01

    Chemotherapy is the main treatment for patients with breast cancer metastases, but natural alternatives have been receiving attention for their potential as novel anti-tumor reagents. Amplexicaule A (APA) is a flavonoid glucoside isolated from rhizomes of Polygonum amplexicaule D. Don var. sinense Forb (PADF). We found that APA has anti-tumor effects in a breast cancer xenograft mouse model and induces apoptosis in breast cancer cell lines. APA increased levels of cleaved caspase-3,-8,-9 and ...

  19. ING Genes Work as Tumor Suppressor Genes in the Carcinogenesis of Head and Neck Squamous Cell Carcinoma.

    Science.gov (United States)

    Li, Xiaohan; Kikuchi, Keiji; Takano, Yasuo

    2011-01-01

    Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer in the world. The evolution and progression of HNSCC are considered to result from multiple stepwise alterations of cellular and molecular pathways in squamous epithelium. Recently, inhibitor of growth gene (ING) family consisting of five genes, ING1 to ING5, was identified as a new tumor suppressor gene family that was implicated in the downregulation of cell cycle and chromatin remodeling. In contrast, it has been shown that ING1 and ING2 play an oncogenic role in some cancers, this situation being similar to TGF-β. In HNSCC, the ING family has been reported to be downregulated, and ING translocation from the nucleus to the cytoplasm may be a critical event for carcinogenesis. In this paper, we describe our recent results and briefly summarize current knowledge regarding the biologic functions of ING in HNSCC.

  20. Identification of rTid-1, the rat homologue of the drosophila tumor suppressor l(2)tid gene.

    Science.gov (United States)

    Fujita, Masako; Nagai, Yasuo; Sawada, Tohru; Heese, Klaus

    2004-03-01

    Active cell death ('apoptosis' or 'programmed cell death') is essential in the development and homeostasis of multicellular organisms and abnormal inhibition of apoptosis is an indicator of cancer and autoimmune diseases, whereas excessive cell death is implicated in neurodegenerative disorders such as Alzheimer's disease (AD). Here we demonstrate new isoforms of the rat homologue of the drosophila tumor suppressor l(2)tid gene (rTid-1). Moreover, we show that rTid-1 interacts isoform-specifically with the heat-shock-cognate-glucose-regulated protein hscGRP75 and neither induces nor inhibits directly neuronal apoptosis. This finding points to a pivotal role of Tid-1 in the control of cellular survival.

  1. Dissecting functions of the retinoblastoma tumor suppressor and the related pocket proteins by integrating genetic, cell biology, and electrophoretic techniques

    DEFF Research Database (Denmark)

    Hansen, Klaus; Lukas, J; Holm, K

    1999-01-01

    The members of the 'pocket protein' family, comprising the retinoblastoma tumor suppressor (pRB) and its relatives, p107 and p130, negatively regulate cell proliferation and modulate fundamental biological processes including embryonic development, differentiation, homeostatic tissue renewal......, and defense against cancer. The large, multidomain pocket proteins act by binding a plethora of cell fate-determining and growth-stimulatory proteins, the most prominent of which are the E2F/DP transcription factors. These protein-protein interactions are in turn regulated by carefully orchestrated...... phosphorylation events on multiple serine and threonine residues of pRB, p107, and p130, events which are carried out, at least in part, by the cyclin-dependent kinases that form the key elements of the cell cycle machinery. Here we discuss the recently obtained new insights into the diverse functions of the pRB...

  2. 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.

  3. [Current status of p53 tumor suppressor gene as a possible molecular marker of cancer of the prostate].

    Science.gov (United States)

    Peña González, J A; Morote Robles, J; de Torres Ramírez, I M; Martínez Cuenca, E

    1998-04-01

    Diagnosis of prostate cancer has increased over the last few years both in localized and in more advanced stages. At present, several groups are working in the search and evaluation of alternative tumoral markers as the current ones do not cover all the Urologist's needs. In this context, a number of studies on the mutation of the tumour suppressor gen p53 in both localized and metastatic prostate cancer are being carried out. When a noxa acts on the DNA, protein p53 inhibits the cell cycle allowing the repair systems to operate and, if the damage is significant enough, cell apoptosis. The loss of this control mechanism secondary to the synthesis of anomalous proteins can result in the proliferation of neoplastic cells. A revision of the most representative papers in the literature is presented here, addressing the surrounding controversy and the resulting future possibilities.

  4. Blood Serum Alpha Fetoprotein Enhancer Binding Protein, a Tumor Suppressor, Decreases in Chronic HBV Hepatitis Patients as Hepatocellular Cancer Appears

    Directory of Open Access Journals (Sweden)

    James N. Riggins

    2010-01-01

    Full Text Available Chronic hepatitis increases the risk of hepatocellular carcinoma (HCC. To test whether circulating proteins reflect hepatic carcinogenesis, sera from patients and controls were albumin depleted, enriched for glycoproteins, digested with trypsin, and subjected to reverse phase chromatography and tandem mass spectrometry. Alpha-fetoprotein enhancer binding protein (AFPebp, a tumor suppressor, was repeatedly identified in sera from chronic HBV hepatitis patients. We independently identified and quantified AFPebp with a deuterated, phenylisocyanate-labeled synthetic peptide standard. Elevated AFPebp levels in sera from chronic HBV hepatitis patients decreased as cancer developed. These data suggest that rising AFPebp levels in chronic HBV hepatitis may be protective, while falling levels may contribute to HCC development.

  5. BTG2 is a tumor suppressor gene upregulated by p53 and PTEN in human bladder carcinoma cells.

    Science.gov (United States)

    Tsui, Ke-Hung; Chiang, Kun-Chun; Lin, Yu-Hsiang; Chang, Kang-Shuo; Feng, Tsui-Hsia; Juang, Horng-Heng

    2017-12-13

    Although widely deemed as a tumor suppressor gene, the role of B-cell translocation gene 2 (BTG2) in bladder cancer is still inconclusive. We investigated the role and regulatory mechanism of BTG2 in bladder cancer. BTG2 expression in human bladder tissues was determined by RT-qPCR and immunoblotting assays. Expressions of BTG2 and PTEN in bladder carcinoma cells were determined by immunoblotting, RT-qPCR, or reporter assays. The 3 H-thymidine incorporation assay, flow cytometry, and the xenograft animal model were used to determine the cell growth. BTG2 expression was lower in human bladder cancer tissues than normal bladder tissues. Highly differentiated bladder cancer cells, RT4, expressed higher BTG2 than the less-differentiated bladder cancer cells, HT1376 and T24. Overexpression of BTG2 in T24 cells inhibited cell growth in vitro and in vivo. Camptothecin and doxorubicin treatments in RT-4 cells or transient overexpression of p53 into p53-mutant HT1376 cells induced p53 and BTG2 expression. Further reporter assays with site-mutation of p53 response element from GGGAAAGTCC to GGAGTCC within BTG2 promoter area showed that p53-induced BTG2 gene expression was dependent on the p53 response element. Ectopic PTEN overexpression in T24 cells blocked the Akt signal pathway which attenuated cell growth via upregualtion of BTG2 gene expression, while reverse effect was found in PTEN-knockdown RT-4 cells. PTEN activity inhibitor (VO-OHpic) treatment decreased BTG2 expression in RT-4 and PTEN-overexpressed T24 cells. Our results suggested that BTG2 functioned as a bladder cancer tumor suppressor gene, and was induced by p53 and PTEN. Modulation of BTG2 expression seems a promising way to treat human bladder cancer. © 2017 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

  6. The antimicrobial peptide pardaxin exerts potent anti-tumor activity against canine perianal gland adenoma.

    Science.gov (United States)

    Pan, Chieh-Yu; Lin, Chao-Nan; Chiou, Ming-Tang; Yu, Chao Yuan; Chen, Jyh-Yih; Chien, Chi-Hsien

    2015-02-10

    Pardaxin is an antimicrobial peptide of 33 amino acids, originally isolated from marine fish. We previously demonstrated that pardaxin has anti-tumor activity against murine fibrosarcoma, both in vitro and in vivo. In this study, we examined the anti-tumor activity, toxicity profile, and maximally-tolerated dose of pardaxin treatment in dogs with different types of refractory tumor. Local injection of pardaxin resulted in a significant reduction of perianal gland adenoma growth between 28 and 38 days post-treatment. Surgical resection of canine histiocytomas revealed large areas of ulceration, suggesting that pardaxin acts like a lytic peptide. Pardaxin treatment was not associated with significant variations in blood biochemical parameters or secretion of immune-related proteins. Our findings indicate that pardaxin has strong therapeutic potential for treating perianal gland adenomas in dogs. These data justify the veterinary application of pardaxin, and also provide invaluable information for veterinary medicine and future human clinical trials.

  7. Re-expression of methylation-induced tumor suppressor gene silencing is associated with the state of histone modification in gastric cancer cell lines

    OpenAIRE

    Meng, Chun-Feng; Zhu, Xin-Jiang; Peng, Guo; Dai, Dong-Qiu

    2007-01-01

    AIM: To identify the relationship between DNA hyper-methylation and histone modification at a hyperme-thylated, silenced tumor suppressor gene promoter in human gastric cancer cell lines and to elucidate whether alteration of DNA methylation could affect histone modification.

  8. Zebrafish mutants in the von Hippel-Lindau tumor suppressor display a hypoxic response and recapitulate key aspects of Chuvash polycythemia

    NARCIS (Netherlands)

    van Rooijen, E.; Voest, E.E.; Logister, I.; Korving, J.; Schwerte, T.; Schulte-Merker, S.; Giles, R.H.; van Eeden, F.J.

    2009-01-01

    We have generated 2 zebrafish lines carrying inactivating germline mutations in the von Hippel-Lindau (VHL) tumor suppressor gene ortholog vhl. Mutant embryos display a general systemic hypoxic response, including the up-regulation of hypoxia-induced genes by 1 day after fertilization and a severe

  9. Phenformin Inhibits Myeloid-Derived Suppressor Cells and Enhances the Anti-Tumor Activity of PD-1 Blockade in Melanoma.

    Science.gov (United States)

    Kim, Sun Hye; Li, Man; Trousil, Sebastian; Zhang, Yaqing; Pasca di Magliano, Marina; Swanson, Kenneth D; Zheng, Bin

    2017-08-01

    Biguanides, such as the diabetes therapeutics metformin and phenformin, have shown antitumor activity both in vitro and in vivo. However, their potential effects on the tumor microenvironment are largely unknown. Here we report that phenformin selectively inhibits granulocytic myeloid-derived suppressor cells in spleens of tumor-bearing mice and ex vivo. Phenformin induces production of reactive oxygen species in granulocytic myeloid-derived suppressor cells, whereas the antioxidant N-acetylcysteine attenuates the inhibitory effects of phenformin. Co-treatment of phenformin enhances the effect of anti-PD-1 antibody therapy on inhibiting tumor growth in the BRAF V600E/PTEN-null melanoma mouse model. Combination of phenformin and anti PD-1 cooperatively induces CD8(+) T-cell infiltration and decreases levels of proteins that are critical for immune suppressive activities of myeloid-derived suppressor cells. Our findings show a selective, inhibitory effect of phenformin on granulocytic myeloid-derived suppressor cell-driven immune suppression and support that phenformin improves the anti-tumor activity of PD-1 blockade immunotherapy in melanoma. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  10. Analysis of a new homozygous deletion in the tumor suppressor region at 3p12.3 reveals two novel intronic noncoding RNA genes

    NARCIS (Netherlands)

    Angeloni, Debora; ter Elst, Arja; Wei, Ming Hui; van der Veen, Anneke Y.; Braga, Eleonora A.; Klimov, Eugene A.; Timmer, Tineke; Korobeinikova, Luba; Lerman, Michael I.; Buys, Charles H. C. M.

    Homozygous deletions or loss of heterozygosity (LOH) at human chromosome band 3p12 are consistent features of lung and other malignancies, suggesting the presence of a tumor suppressor gene(s) (TSG) at this location. Only one gene has been cloned thus far from the overlapping region deleted in lung

  11. Molecular Characterization of the Tumor Suppressor Candidate 5 Gene: Regulation by PPARg and Identification of TUSC5 Coding Variants in Lean and Obese Humans

    Science.gov (United States)

    Tumor suppressor candidate 5 (Tusc5) is a cold-regulated gene expressed abundantly in human and rodent white adipose tissue (WAT), rodent brown adipose tissue (BAT), and peripheral afferent neurons. Strong adipocyte expression and our observation of increased expression following peroxisome prolifer...

  12. MicroRNA-32 functions as a tumor suppressor and directly targets EZH2 in uveal melanoma.

    Science.gov (United States)

    Ma, Y B; Song, D W; Nie, R H; Mu, G Y

    2016-05-13

    MicroRNA-32 (miR-32) has been shown to be dysregulated in some human malignancies and this has been found to be correlated with tumor progression. However, its role in uveal melanoma formation and progression remains largely unknown. Thus, the aim of this study was to explore the expression and function of miR-32 in human uveal melanoma. Using quantitative reverse transcription-polymerase chain reaction, we detected miR-32 expression in uveal melanoma tumor tissues and cell lines. The effects of miR-32 on the biological behavior of uveal melanoma cells were also investigated. Finally, the potential regulatory function of miR-32 on EZH2 expression was confirmed. miR-32 expression levels were significantly downregulated in uveal melanoma samples and cell lines (both P 32 could inhibit uveal melanoma cell proliferation, migration, and invasion, and promote cell apoptosis in vitro. Further, EZH2 was confirmed as a direct target of miR-32 by using the luciferase reporter assay. These findings indicate that miR-32 may function as a novel tumor suppressor in uveal melanoma and could be a potential therapeutic target for this disease.

  13. Caffeine mediates sustained inactivation of breast cancer-associated myofibroblasts via up-regulation of tumor suppressor genes.

    Science.gov (United States)

    Al-Ansari, Mysoon M; Aboussekhra, Abdelilah

    2014-01-01

    Active cancer-associated fibroblasts (CAFs) or myofibroblasts play important roles not only in the development and progression of breast carcinomas, but also in their prognosis and treatment. Therefore, targeting these cells through suppressing their supportive procarcinogenic paracrine effects is mandatory for improving the current therapies that are mainly targeting tumor cells. To this end, we investigated the effect of the natural and pharmacologically safe molecule, caffeine, on CAF cells and their various procarcinogenic effects. We have shown here that caffeine up-regulates the tumor suppressor proteins p16, p21, p53 and Cav-1, and reduces the expression/secretion of various cytokines (IL-6, TGF-β, SDF-1 and MMP-2), and down-regulates α-SMA. Furthermore, caffeine suppressed the migratory/invasiveness abilities of CAF cells through PTEN-dependent Akt/Erk1/2 inactivation. Moreover, caffeine reduced the paracrine pro-invasion/-migration effects of CAF cells on breast cancer cells. These results indicate that caffeine can inactivate breast stromal myofibroblasts. This has been confirmed by showing that caffeine also suppresses the paracrine pro-angiogenic effect of CAF cells through down-regulating HIF-1αand its downstream effector VEGF-A. Interestingly, these effects were sustained in absence of caffeine. The present findings provide a proof of principle that breast cancer myofibroblasts can be inactivated, and thereby caffeine may provide a safe and effective prevention against breast tumor growth/recurrence through inhibition of the procarcinogenic effects of active stromal fibroblasts.

  14. Impact of Natural Compounds on DNA Methylation Levels of the Tumor Suppressor Gene RASSF1A in Cancer.

    Science.gov (United States)

    Dammann, Reinhard H; Richter, Antje M; Jiménez, Adriana P; Woods, Michelle; Küster, Miriam; Witharana, Chamindri

    2017-10-17

    Epigenetic inactivation of tumor suppressor genes (TSG) is a fundamental event in the pathogenesis of human cancer. This silencing is accomplished by aberrant chromatin modifications including DNA hypermethylation of the gene promoter. One of the most frequently hypermethylated TSG in human cancer is the Ras Association Domain Family 1A ( RASSF1A ) gene. Aberrant methylation of RASSF1A has been reported in melanoma, sarcoma and carcinoma of different tissues. RASSF1A hypermethylation has been correlated with tumor progression and poor prognosis. Reactivation of epigenetically silenced TSG has been suggested as a therapy in cancer treatment. In particular, natural compounds isolated from herbal extracts have been tested for their capacity to induce RASSF1A in cancer cells, through demethylation. Here, we review the treatment of cancer cells with natural supplements (e.g., methyl donors, vitamins and polyphenols) that have been utilized to revert or prevent the epigenetic silencing of RASSF1A . Moreover, we specify pathways that were involved in RASSF1A reactivation. Several of these compounds (e.g., reseveratol and curcumin) act by inhibiting the activity or expression of DNA methyltransferases and reactive RASSF1A in cancer. Thus natural compounds could serve as important agents in tumor prevention or cancer therapy. However, the exact epigenetic reactivation mechanism is still under investigation.

  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. Absence of mutations in the coding sequence of the potential tumor suppressor 3pK in metastatic melanoma

    Directory of Open Access Journals (Sweden)

    Houben Roland

    2005-12-01

    Full Text Available Abstract Background Activation of Ras or Raf contributes to tumorigenesis of melanoma. However, constitutive Raf activation is also a characteristic of the majority of benign melanocytic nevi and high intensity signaling of either Ras or Raf was found to induce growth inhibition and senescence rather than transformation. Since the chromosome 3p kinase (3pK is a target of the Ras/Raf/Mek/Erk signaling pathway which antagonizes the function of the oncogene and anti-differentiation factor Bmi-1, 3pK may function as a tumor suppressor in tumors with constitutive Ras/Raf activation. Consequently, we tested whether inactivating 3pK mutations are present in melanoma. Methods 30 metastatic melanoma samples, which were positive for activating mutations of either BRaf or NRas, were analyzed for possible mutations in the 3pk gene. The 10 coding exons and their flanking intron sequences were amplified by PCR and direct sequencing of the PCR products was performed. Results This analysis revealed that besides the presence of some single nucleotide polymorphisms in the 3pk gene, we could not detect any possible loss of function mutation in any of these 30 metastatic melanoma samples selected for the presence of activating mutations within the Ras/Raf/Mek/Erk signaling pathway. Conclusion Hence, in melanoma with constitutively active Ras/Raf inactivating mutations within the 3pk gene do not contribute to the oncogenic phenotype of this highly malignant tumor.

  17. Senescence-Associated Secretory Phenotypes Reveal Cell-Nonautonomous Functions of Oncogenic RAS and the p53 Tumor Suppressor

    Energy Technology Data Exchange (ETDEWEB)

    Copp& #233; , Jean-Philippe; Patil, Christopher; Rodier, Francis; Sun, Yu; Munoz, Denise; Goldstein, Joshua; Nelson, Peter; Desprez, Pierre-Yves; Campisi, Judith

    2008-10-24

    Cellular senescence suppresses cancer by arresting cell proliferation, essentially permanently, in response to oncogenic stimuli, including genotoxic stress. We modified the use of antibody arrays to provide a quantitative assessment of factors secreted by senescent cells. We show that human cells induced to senesce by genotoxic stress secrete myriad factors associated with inflammation and malignancy. This senescence-associated secretory phenotype (SASP) developed slowly over several days and only after DNA damage of sufficient magnitude to induce senescence. Remarkably similar SASPs developed in normal fibroblasts, normal epithelial cells, and epithelial tumor cells after genotoxic stress in culture, and in epithelial tumor cells in vivo after treatment of prostate cancer patients with DNA-damaging chemotherapy. In cultured premalignant epithelial cells, SASPs induced an epithelial-mesenchyme transition and invasiveness, hallmarks of malignancy, by a paracrine mechanism that depended largely on the SASP factors interleukin (IL)-6 and IL-8. Strikingly, two manipulations markedly amplified, and accelerated development of, the SASPs: oncogenic RAS expression, which causes genotoxic stress and senescence in normal cells, and functional loss of the p53 tumor suppressor protein. Both loss of p53 and gain of oncogenic RAS also exacerbated the promalignant paracrine activities of the SASPs. Our findings define a central feature of genotoxic stress-induced senescence. Moreover, they suggest a cell-nonautonomous mechanism by which p53 can restrain, and oncogenic RAS can promote, the development of age-related cancer by altering the tissue microenvironment.

  18. MiR-564 functions as a tumor suppressor in human lung cancer by targeting ZIC3

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Bin [Department of Oncology, Hubei Cancer Hospital, Wuhan, Hubei 430079 (China); Jia, Lin [Department of Nephrology, The Central Hospital of Wuhan, Wuhan, Hubei 430079 (China); Guo, Qiaojuan [Department of Radiation Oncology, Fujian Provincial Cancer Hospital, Provincial Clinical College of Fujian Medical University, Fuzhou, Fujian 350000 (China); Ren, Hui; Hu, Desheng; Zhou, Xiaoyi; Ren, Qingrong [Department of Oncology, Hubei Cancer Hospital, Wuhan, Hubei 430079 (China); Hu, Yanping, E-mail: huyp1989@163.com [Department of Oncology, Hubei Cancer Hospital, Wuhan, Hubei 430079 (China); Xie, Tao, E-mail: xietao930@hotmail.com [Department of Radiation Oncology, Hubei Cancer Hospital, Wuhan, Hubei 430079 (China)

    2015-11-27

    Although miR-564 was reported to be dysregulated in human malignancy, the function and mechanism of miR-564 in tumorigenesis remains unknown. In the present study, we found that miR-564 frequently downregulated in lung cancer cells and significantly inhibited cell proliferation, cell cycle progression, motility, and the tumorigenicity of lung cancer cells. Moreover, we identified zic family member 3 (ZIC3) as a direct target of miR-564. ZIC3 overexpression impaired the suppressive effects of miR-564 on the capacity of lung cancer cells for proliferation and motility. Finally, we detected the expression level of miR-564 and ZIC3 protein in tissue specimens, and found a significant negative correlation between them. Patients with low levels of miR-564 showed a poorer overall survival. Taken together, our present study revealed the tumor suppressor role of miR-564, indicating restoration of miR-564 as a potential therapeutic strategy for the treatment of lung cancer. - Highlights: • MiR-564 inhibits cancer cell proliferation, cell cycle progression, migration, and invasion. • miR-564 suppresses the tumorigenicity of lung cancer cell in vivo. • ZIC3 is a direct and functional target of miR-564. • The expression of miR-564 was negatively correlated with ZIC3 protein in tumors. • Both low miR-564 and high ZIC3 was associated with tumor stage and prognosis.

  19. Multiple Components of the VHL Tumor Suppressor Complex Are Frequently Affected by DNA Copy Number Loss in Pheochromocytoma

    Directory of Open Access Journals (Sweden)

    David A. Rowbotham

    2014-01-01

    Full Text Available Pheochromocytomas (PCC are rare tumors that arise in chromaffin tissue of the adrenal gland. PCC are frequently inherited through predisposing mutations in genes such as the von Hippel-Lindau (VHL tumor suppressor. VHL is part of the VHL elongin BC protein complex that also includes CUL2/5, TCEB1, TCEB2, and RBX1; in normoxic conditions this complex targets hypoxia-inducible factor 1 alpha (HIF1A for degradation, thus preventing a hypoxic response. VHL inactivation by genetic mechanisms, such as mutation and loss of heterozygosity, inhibits HIF1A degradation, even in the presence of oxygen, and induces a pseudohypoxic response. However, the described <10% VHL mutation rate cannot account for the high frequency of hypoxic response observed. Indeed, little is known about genetic mechanisms disrupting other complex component genes. Here, we show that, in a panel of 171 PCC tumors, 59.6% harbored gene copy number loss (CNL of at least one complex component. CNL significantly reduced gene expression and was associated with enrichment of gene targets controlled by HIF1. Interestingly, we show that VHL-related renal clear cell carcinoma harbored disruption of VHL alone. Our results indicate that VHL elongin BC protein complex components other than VHL could be important for PCC tumorigenesis and merit further investigation.

  20. [Construction of Escherichia coli-Bifidobacterium longum shuttle vector and expression of tumor suppressor gene PTEN in B. longum].

    Science.gov (United States)

    Hou, Xin; Liu, Jun-E

    2006-06-01

    It was reported that Bifidobacterium longum accumulated specifically in hypoxic solid tumors, therefore could be used as a delivery system for cancer-specific gene therapy. Furthermore, construction of E.coli-B. longum shuttle vectors was proved by other research to be an efficient way for stable gene expression in B. longum. To obtain a shuttle vector and analyze the inhibition on mice solid tumors by genetically engineered B. longum, 48 primers with mutual overlaps were designed, assisted by software package Oligo 6.0. By PCR with the above primers, a linear plasmid was synthesized, which consists of pMB1 and HU gene promoter, both from B. longum. pMB-HU was constructed by cloning the synthesized linear plasmid into E.coli vector pMD 18-T, and was proved to be stably replicated in both E.coli DH5alpha and B. longum L17. By inserting PTEN cDNA into pMB-HU, expression vector pMB-HU-PTEN was obtained, in which PTEN gene was reported as a major tumor suppressor gene encoding a dual-specificity phosphatase. pMB-HU-PTEN was then transferred into B. longum L17 by electroporation. After transformation, an effective expression of PTEN in B. longum L17 was confirmed by Western blot, and significant inhibition on growth of mice solid tumors was also observed with the above genetically engineered B. longum. Those obtained results have laid foundation for tumor-targeting gene therapy with B. longum.

  1. Tumor-specific suppressor T-cells which inhibit the in vitro generation of cytolytic T-cells from immune and early tumor-bearing host spleens.

    Science.gov (United States)

    Bear, H D

    1986-04-01

    Spleen cells from DBA/2 mice, after immunization with syngeneic P815 mastocytoma cells and Corynebacterium parvum, respond to P815 in vitro with a brisk, secondary-type generation of cytotoxic cells. This cytotoxicity is mediated by antigen-specific T-lymphocytes and correlates with resistance to in vivo challenge. This model confirms the observations of previous investigators made in semisyngeneic hosts using an in vivo transfer model. Spleen cells from "early" tumor-bearing hosts (TBHs), 7-12 days after intradermal (i.d.) inoculation of 10(6) P815 cells alone, made a similar, but generally higher, cytotoxic T-lymphocyte (CTL) response in vitro. Spleen cells from "late" TBHs (18-28 days) completely suppressed the in vitro CTL response of immune cells (e.g., from 71% specific release in controls down to 8% at an effector: target ratio of 40:1). Early i.d. TBH spleen cells, because of their higher level response, appeared to be resistant to this suppression (85% release for controls and 84% when suppressor cells were added at 40:1). By testing early TBH CTL at lower effector: target ratios, however, suppression by late TBH spleen cells could be readily demonstrated. When TBHs were inoculated s.c. instead of i.d. or with lower doses of tumor cells, responses were lower and susceptibility of splenic CTLs to suppression was increased. At intermediate times after tumor inoculation (14-20 days), spleen cells from TBHs still can respond in vitro, but they are completely suppressed by spleen cells from late TBHs. The suppressor cells are antigen-specific, radiation-sensitive, Thy1+ cells.

  2. Lactoferrin Exerts Antitumor Effects by Inhibiting Angiogenesis in a HT29 Human Colon Tumor Model.

    Science.gov (United States)

    Li, Hui-Ying; Li, Ming; Luo, Chao-Chao; Wang, Jia-Qi; Zheng, Nan

    2017-12-06

    To investigate the effect and potential mechanisms of lactoferrin on colon cancer cells and tumors, HT29 and HCT8 cells were exposed to varying concentrations of lactoferrin, and the impacts on cell proliferation, migration, and invasion were observed. Cell proliferation test showed that high dosage of lactoferrin (5-100 mg/mL) inhibited cell viability in a dose-dependent manner, with the 50% concentration of inhibition at 81.3 ± 16.7 mg/mL and 101 ± 23.8 mg/mL for HT29 and HCT8 cells, respectively. Interestingly, migration and invasion of the cells were inhibited dramatically by 20 mg/mL lactoferrin, consistent with the significant down regulation of VEGFR2, VEGFA, pPI3K, pAkt, and pErk1/2 proteins. HT29 was chosen as the sensitive cell line to construct a tumor-bearing nude mice model. Notably, HT29 tumor weight was greatly reduced in both the lactoferrin group (26.5 ± 6.7 mg) and the lactoferrin/5-Fu group (14.5 ± 5.1 mg), compared with the control one (39.3 ± 6.5 mg), indicating that lactoferrin functioned as a tumor growth inhibitor. Considering lactoferrin also reduced the growth of blood vessels and the degree of malignancy, we concluded that HT29 tumors were effectively suppressed by lactoferrin, which might be achieved by regulation of phosphorylation from various kinases and activation of the VEGFR2-PI3K/Akt-Erk1/2 pathway.

  3. Dynamin 3: a new candidate tumor suppressor gene in hepatocellular carcinoma detected by triple combination array analysis

    Directory of Open Access Journals (Sweden)

    Inokawa Y

    2013-10-01

    Full Text Available Yoshikuni Inokawa,1 Shuji Nomoto,1 Mitsuhiro Hishida,1 Masamichi Hayashi,1 Mitsuro Kanda,1 Yoko Nishikawa,1 Shin Takeda,2 Michitaka Fujiwara,1 Masahiko Koike,1 Hiroyuki Sugimoto,1 Tsutomu Fujii,1 Goro Nakayama,1 Suguru Yamada,1 Chie Tanaka,1 Daisuke Kobayashi,1 Yasuhiro Kodera11Gastroenterological Surgery, Nagoya University Graduate School of Medicine, Nagoya Japan; 2Department of Surgery, Nagoya Medical Center, Nagoya, JapanBackground: To identify genes associated with hepatocellular carcinoma (HCC pathogenesis, we developed a triple combination array strategy comprising methylation, gene expression, and single nucleotide polymorphism (SNP array analysis.Methods: Surgical specimens obtained from a 68-year-old female HCC patient were analyzed by triple combination array, and identified Dynamin 3 (DNM3 as a candidate tumor suppressor gene in HCC. Subsequently, samples from 48 HCC patients were evaluated for DNM3 methylation and expression status using methylation specific polymerase chain reaction (PCR; MSP and semi-quantitative reverse transcriptase (RT-PCR, respectively. The relationship between clinicopathological factors and DNM3 methylation status was also investigated.Results: DNM3 was shown to be hypermethylated (methylation value 0.879, range 0–1.0 in cancer tissue compared with adjacent normal tissue (0.213 by methylation array in the 68-year-old female patient. Expression arrays revealed decreased expression of DNM3 in cancerous tissue. SNP arrays revealed that the copy number of chromosome 1q24.3, in which DNM3 resides, was normal. MSP revealed hypermethylation of the DNM3 promoter region in 33 of 48 tumor samples. A trend toward decreased DNM3 expression was observed in patients with DNM3 promoter methylation (P = 0.189. Furthermore, patients with reduced expression of DNM3 in tumor tissues exhibited worse prognosis with decreased disease specific survival compared to patients without decreased expression (P = 0.014.Conclusion: The

  4. Differential expression of the PTEN tumor suppressor protein in fetal and adult neuroendocrine tissues and tumors: progressive loss of PTEN expression in poorly differentiated neuroendocrine neoplasms.

    Science.gov (United States)

    Wang, Luoquan; Ignat, Ana; Axiotis, Constantine A

    2002-06-01

    Genetic alteration and loss of expression of tumor suppressor gene PTEN has been found in carcinomas of the breast, prostate, and endometrium, as well as in gliomas. PTEN expression in neural crest/neuroendocrine (NC/NE) tissues and in neoplasms has not been reported. This study examines PTEN expression in embryonal, fetal, and adult tissues by immunohistochemistry. The authors found high PTEN expression in embryonal, fetal, and adult NC/NE tissues. The authors also study the PTEN expression in NC/NE neoplasms (N = 37), including 5 melanocytic nevi, 2 melanomas, 9 carcinoids, 2 moderately differentiated neuroendocrine carcinomas, 13 poorly differentiated neuroendocrine carcinomas, 2 paragangliomas, 2 pheochromocytomas, 2 medullary thyroid carcinomas, and 1 neuroblastoma. All carcinoid tumors and melanocytic nevi showed moderate or strong immunostaining for PTEN. In contrast, the majority of poorly differentiated neuroendocrine carcinomas (7 of 13) were negative for PTEN (54%); the remainder showed diminished reactivity. The two melanomas studied were also negative for PTEN immunostaining. The paragangliomas, pheochromocytomas, medullary thyroid carcinomas, and neuroblastoma all showed a strong PTEN stain. The authors postulate that PTEN is a differentiation marker for NC/NE tissue and tumors and that loss of PTEN expression may represent an important step in the progression of NE tumors.

  5. Role of PINCH and its partner tumor suppressor Rsu-1 in regulating liver size and tumorigenesis.

    Directory of Open Access Journals (Sweden)

    Shashikiran Donthamsetty

    Full Text Available Particularly interesting new cysteine-histidine-rich protein (PINCH protein is part of the ternary complex known as the IPP (integrin linked kinase (ILK-PINCH-Parvin-α complex. PINCH itself binds to ILK and to another protein known as Rsu-1 (Ras suppressor 1. We generated PINCH 1 and PINCH 2 Double knockout mice (referred as PINCH DKO mice. PINCH2 elimination was systemic whereas PINCH1 elimination was targeted to hepatocytes. The genetically modified mice were born normal. The mice were sacrificed at different ages after birth. Soon after birth, they developed abnormal hepatic histology characterized by disorderly hepatic plates, increased proliferation of hepatocytes and biliary cells and increased deposition of extracellular matrix. After a sustained and prolonged proliferation of all epithelial components, proliferation subsided and final liver weight by the end of 30 weeks in livers with PINCH DKO deficient hepatocytes was 40% larger than the control mice. The livers of the PINCH DKO mice were also very stiff due to increased ECM deposition throughout the liver, with no observed nodularity. Mice developed liver cancer by one year. These mice regenerated normally when subjected to 70% partial hepatectomy and did not show any termination defect. Ras suppressor 1 (Rsu-1 protein, the binding partner of PINCH is frequently deleted in human liver cancers. Rsu-1 expression is dramatically decreased in PINCH DKO mouse livers. Increased expression of Rsu-1 suppressed cell proliferation and migration in HCC cell lines. These changes were brought about not by affecting activation of Ras (as its name suggests but by suppression of Ras downstream signaling via RhoGTPase proteins. In conclusion, our studies suggest that removal of PINCH results in enlargement of liver and tumorigenesis. Decreased levels of Rsu-1, a partner for PINCH and a protein often deleted in human liver cancer, may play an important role in the development of the observed phenotype.

  6. Neurofibromatosis type 2 tumor suppressor protein, NF2, induces proteasome-mediated degradation of JC virus T-antigen in human glioblastoma.

    Directory of Open Access Journals (Sweden)

    Sarah Beltrami

    Full Text Available Neurofibromatosis type 2 protein (NF2 has been shown to act as tumor suppressor primarily through its functions as a cytoskeletal scaffold. However, NF2 can also be found in the nucleus, where its role is less clear. Previously, our group has identified JC virus (JCV tumor antigen (T-antigen as a nuclear binding partner for NF2 in tumors derived from JCV T-antigen transgenic mice. The association of NF2 with T-antigen in neuronal origin tumors suggests a potential role for NF2 in regulating the expression of the JCV T-antigen. Here, we report that NF2 suppresses T-antigen protein expression in U-87 MG human glioblastoma cells, which subsequently reduces T-antigen-mediated regulation of the JCV promoter. When T-antigen mRNA was quantified, it was determined that increasing expression of NF2 correlated with an accumulation of T-antigen mRNA; however, a decrease in T-antigen at the protein level was observed. NF2 was found to promote degradation of ubiquitin bound T-antigen protein via a proteasome dependent pathway concomitant with the accumulation of the JCV early mRNA encoding T-antigen. The interaction between T-antigen and NF2 maps to the FERM domain of NF2, which has been shown previously to be responsible for its tumor suppressor activity. Co-immunoprecipitation assays revealed a ternary complex among NF2, T-antigen, and the tumor suppressor protein, p53 within a glioblastoma cell line. Further, these proteins were detected in various degrees in patient tumor tissue, suggesting that these associations may occur in vivo. Collectively, these results demonstrate that NF2 negatively regulates JCV T-antigen expression by proteasome-mediated degradation, and suggest a novel role for NF2 as a suppressor of JCV T-antigen-induced cell cycle regulation.

  7. A Genetic Screen for Genes Involved in BRCA 1 Tumor Suppressor Function

    National Research Council Canada - National Science Library

    Verma, Inder; Zhu, Quan

    2007-01-01

    Based on our initial screening, we have identified a number of candidates that are involved in DNA damage repair pathway mediated by BRCA1, which is an important aspect of tumor suppression of the molecular...

  8. The epigenetic modifier PRDM5 functions as a tumor suppressor through modulating WNT/β-catenin signaling and is frequently silenced in multiple tumors.

    Directory of Open Access Journals (Sweden)

    Xing-sheng Shu

    Full Text Available BACKGROUND: PRDM (PRDI-BF1 and RIZ domain containing proteins are zinc finger proteins involved in multiple cellular regulations by acting as epigenetic modifiers. We studied a recently identified PRDM member PRDM5 for its epigenetic abnormality and tumor suppressive functions in multiple tumorigeneses. METHODOLOGY/PRINCIPAL FINDINGS: Semi-quantitative RT-PCR showed that PRDM5 was broadly expressed in human normal tissues, but frequently silenced or downregulated in multiple carcinoma cell lines due to promoter CpG methylation, including 80% (4/5 nasopharyngeal, 44% (8/18 esophageal, 76% (13/17 gastric, 50% (2/4 cervical, and 25% (3/12 hepatocellular carcinoma cell lines, but not in any immortalized normal epithelial cell lines. PRDM5 expression could be restored by 5-aza-2'-deoxycytidine demethylation treatment in silenced cell lines. PRDM5 methylation was frequently detected by methylation-specific PCR (MSP in multiple primary tumors, including 93% (43/46 nasopharyngeal, 58% (25/43 esophageal, 88% (37/42 gastric and 63% (29/46 hepatocellular tumors. PRDM5 was further found a stress-responsive gene, but its response was impaired when the promoter was methylated. Ectopic PRDM5 expression significantly inhibited tumor cell clonogenicity, accompanied by the inhibition of TCF/β-catenin-dependent transcription and downregulation of CDK4, TWIST1 and MDM2 oncogenes, while knocking down of PRDM5 expression lead to increased cell proliferation. ChIP assay showed that PRDM5 bound to its target gene promoters and suppressed their transcription. An inverse correlation between the expression of PRDM5 and activated β-catenin was also observed in cell lines. CONCLUSIONS/SIGNIFICANCE: PRDM5 functions as a tumor suppressor at least partially through antagonizing aberrant WNT/β-catenin signaling and oncogene expression. Frequent epigenetic silencing of PRDM5 is involved in multiple tumorigeneses, which could serve as a tumor biomarker.

  9. The role of UV induced lesions in skin carcinogenesis: an overview of oncogene and tumor suppressor gene modifications in xeroderma pigmentosum skin tumors

    Energy Technology Data Exchange (ETDEWEB)

    Daya-Grosjean, Leela [Laboratory of Genetic Instability and Cancer, UPR2169 CNRS, IFR 54, Institut Gustave Roussy, 39, rue Camille Desmoulins, 94805 Villejuif Cedex (France)]. E-mail: daya@igr.fr; Sarasin, Alain [Laboratory of Genetic Instability and Cancer, UPR2169 CNRS, IFR 54, Institut Gustave Roussy, 39, rue Camille Desmoulins, 94805 Villejuif Cedex (France)

    2005-04-01

    Xeroderma pigmentosum (XP), a rare hereditary syndrome, is characterized by a hypersensitivity to solar irradiation due to a defect in nucleotide excision repair resulting in a predisposition to squamous and basal cell carcinomas as well as malignant melanomas appearing at a very early age. The mutator phenotype of XP cells is evident by the higher levels of UV specific modifications found in key regulatory genes in XP skin tumors compared to those in the same tumor types from the normal population. Thus, XP provides a unique model for the study of unrepaired DNA lesions, mutations and skin carcinogenesis. The high level of ras oncogene activation, Ink4a-Arf and p53 tumor suppressor gene modifications as well as alterations of the different partners of the mitogenic sonic hedgehog signaling pathway (patched, smoothened and sonic hedgehog), characterized in XP skin tumors have clearly demonstrated the major role of the UV component of sunlight in the development of skin tumors. The majority of the mutations are C to T or tandem CC to TT UV signature transitions, occurring at bipyrimidine sequences, the specific targets of UV induced lesions. These characteristics are also found in the same genes modified in sporadic skin cancers but with lower frequencies confirming the validity of studying the XP model. The knowledge gained by studying XP tumors has given us a greater perception of the contribution of genetic predisposition to cancer as well as the consequences of the many alterations which modulate the activities of different genes affecting crucial pathways vital for maintaining cell homeostasis.

  10. Mapping Tumor-Suppressor Genes with Multipoint Statistics from Copy-Number–Variation Data

    OpenAIRE

    Ionita, Iuliana; Daruwala, Raoul-Sam; Mishra, Bud

    2006-01-01

    Array-based comparative genomic hybridization (arrayCGH) is a microarray-based comparative genomic hybridization technique that has been used to compare tumor genomes with normal genomes, thus providing rapid genomic assays of tumor genomes in terms of copy-number variations of those chromosomal segments that have been gained or lost. When properly interpreted, these assays are likely to shed important light on genes and mechanisms involved in the initiation and progression of cancer. Specifi...

  11. Sinks, suppressors and antigen presenters: how lymphodepletion enhances T cell-mediated tumor immunotherapy

    OpenAIRE

    Klebanoff, Christopher A.; Khong, Hung T.; Antony, Paul A.; Palmer, Douglas C.; Restifo, Nicholas P.

    2005-01-01

    Lymphodepletion followed by adoptive cell transfer (ACT) of autologous, tumor-reactive T cells boosts antitumor immunotherapeutic activity in mouse and in humans. In the most recent clinical trials, lymphodepletion together with ACT has an objective response rate of 50% in patients with solid metastatic tumors. The mechanisms underlying this recent advance in cancer immunotherapy are beginning to be elucidated and include: the elimination of cellular cytokine ‘sinks’ for homeostatic γC-cytoki...

  12. Exercise-Induced Catecholamines Activate the Hippo Tumor Suppressor Pathway to Reduce Risks of Breast Cancer Development.

    Science.gov (United States)

    Dethlefsen, Christine; Hansen, Louise S; Lillelund, Christian; Andersen, Christina; Gehl, Julie; Christensen, Jesper F; Pedersen, Bente K; Hojman, Pernille

    2017-09-15

    Strong epidemiologic evidence documents the protective effect of physical activity on breast cancer risk, recurrence, and mortality, but the underlying mechanisms remain to be identified. Using human exercise-conditioned serum for breast cancer cell incubation studies and murine exercise interventions, we aimed to identify exercise factors and signaling pathways involved in the exercise-dependent suppression of breast cancer. Exercise-conditioned serum from both women with breast cancer ( n = 20) and healthy women ( n = 7) decreased MCF-7 (hormone-sensitive) and MDA-MB-231 (hormone-insensitive) breast cancer cell viability in vitro by 11% to 19% and reduced tumorigenesis by 50% when preincubated MCF-7 breast cancer cells were inoculated into NMRI-Foxn1 nu mice. This exercise-mediated suppression of cell viability and tumor formation was completely blunted by blockade of β-adrenergic signaling in MCF-7 cells, indicating that catecholamines were the responsible exercise factors. Both epinephrine (EPI) and norepinephrine (NE) could directly inhibit breast cancer cell viability, as well as tumor growth in vivo EPI and NE activate the tumor suppressor Hippo signaling pathway, and the suppressive effect of exercise-conditioned serum was found to be mediated through phosphorylation and cytoplasmic retention of YAP and reduced expression of downstream target genes, for example, ANKRD1 and CTGF. In parallel, tumor-bearing mice with access to running wheels showed reduced growth of MCF-7 (-36%, P exercise-dependent suppression of breast cancer cell growth. Cancer Res; 77(18); 4894-904. ©2017 AACR . ©2017 American Association for Cancer Research.

  13. Loss of tumor suppressor Merlin results in aberrant activation of Wnt/β-catenin signaling in cancer.

    Science.gov (United States)

    Morrow, K Adam; Das, Shamik; Meng, Erhong; Menezes, Mitchell E; Bailey, Sarah K; Metge, Brandon J; Buchsbaum, Donald J; Samant, Rajeev S; Shevde, Lalita A

    2016-04-05

    The expression of the tumor suppressor Merlin is compromised in nervous system malignancies due to genomic aberrations. We demonstrated for the first time, that in breast cancer, Merlin protein expression is lost due to proteasome-mediated elimination. Immunohistochemical analysis of tumor tissues from patients with metastatic breast cancer revealed characteristically reduced Merlin expression. Importantly, we identified a functional role for Merlin in impeding breast tumor xenograft growth and reducing invasive characteristics. We sought to determine a possible mechanism by which Merlin accomplishes this reduction in malignant activity. We observed that breast and pancreatic cancer cells with loss of Merlin show an aberrant increase in the activity of β-catenin concomitant with nuclear localization of β-catenin. We discovered that Merlin physically interacts with β-catenin, alters the sub-cellular localization of β-catenin, and significantly reduces the protein levels of β-catenin by targeting it for degradation through the upregulation of Axin1. Consequently, restoration of Merlin inhibited β-catenin-mediated transcriptional activity in breast and pancreatic cancer cells. We also present evidence that loss of Merlin sensitizes tumor cells to inhibition by compounds that target β-catenin-mediated activity. Thus, this study provides compelling evidence that Merlin reduces the malignant activity of pancreatic and breast cancer, in part by suppressing the Wnt/β-catenin pathway. Given the potent role of Wnt/β-catenin signaling in breast and pancreatic cancer and the flurry of activity to test β-catenin inhibitors in the clinic, our findings are opportune and provide evidence for Merlin in restraining aberrant activation of Wnt/β-catenin signaling.

  14. Analysis of the Wilms' tumor suppressor gene (WT1) in patients 46,XY disorders of sex development.

    Science.gov (United States)

    Köhler, B; Biebermann, H; Friedsam, V; Gellermann, J; Maier, R F; Pohl, M; Wieacker, P; Hiort, O; Grüters, A; Krude, H

    2011-07-01

    The Wilms' tumor suppressor gene (WT1) is one of the major regulators of early gonadal and kidney development. WT1 mutations have been identified in 46,XY disorders of sex development (DSD) with associated kidney disease and in few isolated forms of 46,XY DSD. The objective of the study was the evaluation of WT1 mutations in different phenotypes of isolated 46,XY DSD and clinical consequences. The design of the study was: 1) sequencing of the WT1 gene in 210 patients with 46,XY DSD from the German DSD network, consisting of 150 males with severe hypospadias (70 without cryptorchidism, 80 with at least one cryptorchid testis), 10 males with vanishing testes syndrome, and 50 raised females with partial to complete 46,XY gonadal dysgenesis; and 2) genotype-phenotype correlation of our and all published patients with 46,XY DSD and WT1 mutations. We have detected WT1 mutations in six of 80 patients with severe hypospadias (7.5%) and at least one cryptorchid testis and in one of 10 patients with vanishing testes syndrome (10%). All patients except one developed Wilms' tumor and/or nephropathy in childhood or adolescence. WT1 analysis should be performed in newborns with complex hypospadias with at least one cryptorchid testis and in isolated 46,XY partial to complete gonadal dysgenesis. Kidney disease might not develop until later life in these cases. WT1 analysis is mandatory in all 46,XY DSD with associated kidney disease. WT1 analysis is not indicated in newborns with isolated hypospadias without cryptorchidism. Patients with WT1 mutations should be followed up closely because the risk of developing a Wilms' tumor, nephropathy, and/or gonadal tumor is very high.

  15. Identification of the long non‑coding RNA LET as a novel tumor suppressor in gastric cancer.

    Science.gov (United States)

    Tian, Jingjing; Hu, Xibao; Gao, Wei; Zhang, Jie; Chen, Ming; Zhang, Xinrong; Ma, Junhong; Yuan, Hongxia

    2017-04-01

    Long non-coding RNAs (lncRNAs) have emerged recently as important factors in regulating fundamental biological processes. Alterations in the expression and function of lncRNAs have been observed to promote tumor formation, progression and metastasis. Although downregulation of the expression levels of LET lncRNA in several tumors has been reported, its role in gastric cancer remains unknown. The aim of the present study was to investigate the expression and function of LET in gastric cancer development. The expression levels of LET in 37 pairs of gastric cancer and adjacent non‑tumor tissues were detected by reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR). In addition, LET expression in gastric cancer cell lines was analyzed by RT‑qPCR assay analysis. Furthermore, the impact of LET on cell proliferation, migration and apoptosis were detected using the cell counting kit‑8, wound scratch and ELISA assays, respectively. The results demonstrated that the expression level of LET was downregulated in gastric cancer tissues and cell lines (SGC‑7901 and MGC‑803) compared with normal tissues and a normal human gastric epithelial cell line (GES‑1). Restoration of LET expression using a synthesized recombinant overexpression vector transfected into SGC‑7901 and MGC‑803 cells, significantly inhibited cell proliferation and migration, and promoted cell apoptosis in vitro. The present study is the first to demonstrate that LET may function as a tumor suppressor in gastric cancer. The results indicate that LET may be a promising biomarker and/or a therapeutic target for gastric cancer.

  16. Ezh2 Acts as a Tumor Suppressor in Kras-driven Lung Adenocarcinoma.

    Science.gov (United States)

    Wang, Yanxiao; Hou, Ning; Cheng, Xuan; Zhang, Jishuai; Tan, Xiaohong; Zhang, Chong; Tang, Yuling; Teng, Yan; Yang, Xiao

    2017-01-01

    Previous studies have suggested that enhancer zeste homolog 2 (Ezh2), a histone methyltransferase subunit of polycomb repressive complex 2 (PRC2), acts as an oncogene in lung adenocarcinoma (ADC) development. However, we found that in human lung ADC samples, deletion and mutations of EZH2 were also frequently present, with 14% of patients harboring loss-of-function EZH2 alterations. To explore the effect of Ezh2 loss on lung tumor formation, lung epithelial Ezh2 gene was deleted in Kras-driven lung ADC mouse model. Unexpectedly, Ezh2 loss dramatically promoted Kras-driven ADC formation. Kras(G12D/+);Ezh2(fl/fl) mice exhibited shorter lifespan, more tumor lesions and higher tumor burden than Kras(G12D/+) mice, suggesting the tumor-suppressive role of Ezh2 in Kras-driven ADCs. Mechanistically, Ezh2 loss amplified Akt and ERK activation through de-repressing its target insulin-like growth factor 1 (Igf1). Additionally, Ezh2 loss cooperated with Kras mutation to exacerbate the inflammatory response, as shown by massive macrophage and neutrophil infiltrates, as well as a marked increase in tumor-associated cytokines such as IL-6 and TNF-α. Taken together, our findings revealed the tumor suppressive function of Ezh2 in Kras-driven ADCs, underlining the importance of revaluating the application of EZH2 inhibitors in a variety of cancers.

  17. Association of Cigarette Smoking with Aberrant Methylation of the Tumor Suppressor Gene RARβ2 in Papillary Thyroid Cancer

    Directory of Open Access Journals (Sweden)

    Katja eKiseljak-Vassiliades

    2011-12-01

    Full Text Available Aberrant gene methylation is often seen in thyroid cancer, a common endocrine malignancy. Tobacco smoking has been shown to be associated with aberrant gene methylation in several cancers, but its relationship with gene methylation in thyroid cancer has not been examined. In the present study, we investigated the relationship between smoking of patients and aberrant methylation of tumor suppressor genes for TIMP3, SLC5A8, death-associated protein kinase, and retinoic acid receptor β2 (RARβ2 in papillary thyroid cancer (PTC, the most common type of thyroid cancer. The promoter methylation status of these genes was analyzed using quantitative real-time methylation-specific PCR on bisulfite-treated genomic DNA isolated from tumor tissues and correlated with smoking history of the patients. Among the four genes, methylation of the RARβ2 gene was significantly associated with smoking and other three genes showed a trend of association. Specifically, among the 138 patients investigated, 13/42 (31.0% ever smokers vs. 10/96 (10.4% never smokers harbored methylation of the RARβ2 gene (P = 0.003. This association was highly significant also in the subset of conventional variant PTC (P = 0.005 and marginally significant in follicular variant PTC (p = 0.06. The results demonstrate that smoking-associated aberrant methylation of the RARβ2 gene is a specific molecular event that may represent an important mechanism in thyroid tumorigenesis in smokers.

  18. Loss of the tumor suppressor gene NF2, encoding merlin, constitutively activates integrin-dependent mTORC1 signaling.

    Science.gov (United States)

    López-Lago, Miguel A; Okada, Tomoyo; Murillo, Miguel M; Socci, Nick; Giancotti, Filippo G

    2009-08-01

    Integrin signaling promotes, through p21-activated kinase, phosphorylation and inactivation of the tumor suppressor merlin, thus removing a block to mitogenesis in normal cells. However, the biochemical function of merlin and the effector pathways critical for the pathogenesis of malignant mesothelioma and other NF2-related malignancies are not known. We report that integrin-specific signaling promotes activation of mTORC1 and cap-dependent mRNA translation. Depletion of merlin rescues mTORC1 signaling in cells deprived of anchorage to a permissive extracellular matrix, suggesting that integrin signaling controls mTORC1 through inactivation of merlin. This signaling pathway controls translation of the cyclin D1 mRNA and, thereby, cell cycle progression. In addition, it promotes cell survival. Analysis of a panel of malignant mesothelioma cell lines reveals a strong correlation between loss of merlin and activation of mTORC1. Merlin-negative lines are sensitive to the growth-inhibitory effect of rapamycin, and the expression of recombinant merlin renders them partially resistant to rapamycin. Conversely, depletion of merlin restores rapamycin sensitivity in merlin-positive lines. These results indicate that integrin-mediated adhesion promotes mTORC1 signaling through the inactivation of merlin. Furthermore, they reveal that merlin-negative mesotheliomas display unregulated mTORC1 signaling and are sensitive to rapamycin, thus providing a preclinical rationale for prospective, biomarker-driven clinical studies of mTORC1 inhibitors in these tumors.

  19. The neurofibromatosis 2 tumor suppressor gene product, merlin, regulates human meningioma cell growth by signaling through YAP.

    Science.gov (United States)

    Striedinger, Katherine; VandenBerg, Scott R; Baia, Gilson S; McDermott, Michael W; Gutmann, David H; Lal, Anita

    2008-11-01

    Neurofibromatosis type 2 (NF2) is an autosomal dominant disorder characterized by the occurrence of schwannomas and meningiomas. Several studies have examined the ability of the NF2 gene product, merlin, to function as a tumor suppressor in diverse cell types; however, little is known about merlin growth regulation in meningiomas. In Drosophila, merlin controls cell proliferation and apoptosis by signaling through the Hippo pathway to inhibit the function of the transcriptional coactivator Yorkie. The Hippo pathway is conserved in mammals. On the basis of these observations, we developed human meningioma cell lines matched for merlin expression to evaluate merlin growth regulation and investigate the relationship between NF2 status and Yes-associated protein (YAP), the mammalian homolog of Yorkie. NF2 loss in meningioma cells was associated with loss of contact-dependent growth inhibition, enhanced anchorage-independent growth and increased cell proliferation due to increased S-phase entry. In addition, merlin loss in both meningioma cell lines and primary tumors resulted in increased YAP expression and nuclear localization. Finally, siRNA-mediated reduction of YAP in NF2-deficient meningioma cells rescued the effects of merlin loss on cell proliferation and S-phase entry. Collectively, these results represent the first demonstration that merlin regulates cell growth in human cancer cells by suppressing YAP.

  20. MicroRNA-140 mediates RB tumor suppressor function to control stem cell-like activity through interleukin-6.

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    Yoshida, Akiyo; Kitajima, Shunsuke; Li, Fengkai; Cheng, Chaoyang; Takegami, Yujiro; Kohno, Susumu; Wan, Yuan Song; Hayashi, Naoyuki; Muranaka, Hayato; Nishimoto, Yuuki; Nagatani, Naoko; Nishiuchi, Takumi; Thai, Tran C; Suzuki, Sawako; Nakao, Shinji; Tanaka, Tomoaki; Hirose, Osamu; Barbie, David A; Takahashi, Chiaki

    2017-02-21

    We established an in vitro cell culture system to determine novel activities of the retinoblastoma (Rb) protein during tumor progression. Rb depletion in p53-null mouse-derived soft tissue sarcoma cells induced a spherogenic phenotype. Cells retrieved from Rb-depleted spheres exhibited slower proliferation and less efficient BrdU incorporation, however, much higher spherogenic activity and aggressive behavior. We discovered six miRNAs, including mmu-miR-18a, -25, -29b, -140, -337, and -1839, whose expression levels correlated tightly with the Rb status and spherogenic activity. Among these, mmu-miR-140 appeared to be positively controlled by Rb and to antagonize the effect of Rb depletion on spherogenesis and tumorigenesis. Furthermore, among genes potentially targeted by mmu-miR-140, Il-6 was upregulated by Rb depletion and downregulated by mmu-mir-140 overexpression. Altogether, we demonstrate the possibility that mmu-mir-140 mediates the Rb function to downregulate Il-6 by targeting its 3'-untranslated region. Finally, we detected the same relationship among RB, hsa-miR-140 and IL-6 in a human breast cancer cell line MCF-7. Because IL-6 is a critical modulator of malignant features of cancer cells and the RB pathway is impaired in the majority of cancers, hsa-miR-140 might be a promising therapeutic tool that disrupts linkage between tumor suppressor inactivation and pro-inflammatory cytokine response.

  1. New Insight into microRNA Functions in Cancer: Oncogene-microRNA-Tumor Suppressor Gene Network.

    Science.gov (United States)

    Zhou, Kecheng; Liu, Minxia; Cao, Yi

    2017-01-01

    Tumorigenesis is a multi-step and complex process with multi-factors involved. Deregulated oncogenes and tumor suppressor genes (TSGs) induced by genetic and epigenetic factors are considered as the driving force in the development and progression of cancer. Besides, microRNAs (miRNAs) act vital roles in tumorigenesis through regulating some oncogenes and TSGs. Interestingly, miRNAs are also regulated by oncogenes and TSGs. Considering the entangled regulation, here we propose a new insight into these regulation relationships in cancer: oncogene-miRNA-TSG network, which further emphasizes roles of miRNA, as well as highlights the network regulation among oncogene, miRNA, and TSG during tumorigenesis. The oncogene-miRNA-TSG network demonstrates that oncogenes and TSGs not only show functional synergy, but also there are regulatory relationships among oncogenes and TSGs during tumorigenesis, which could be mediated by miRNAs. In view of the oncogene-miRNA-TSG network involved in many oncogenes, miRNAs, and TSGs, as well as occurring in various tumor types, the anomaly of this network may be a common event in cancers and participates in tumorigenesis. This hypothesis broadens horizons of molecular mechanisms underlying tumorigenesis, and may provide a new promising venue for the prediction, diagnosis, and even therapy of cancer.

  2. New Insight into microRNA Functions in Cancer: Oncogene–microRNA–Tumor Suppressor Gene Network

    Science.gov (United States)

    Zhou, Kecheng; Liu, Minxia; Cao, Yi

    2017-01-01

    Tumorigenesis is a multi-step and complex process with multi-factors involved. Deregulated oncogenes and tumor suppressor genes (TSGs) induced by genetic and epigenetic factors are considered as the driving force in the development and progression of cancer. Besides, microRNAs (miRNAs) act vital roles in tumorigenesis through regulating some oncogenes and TSGs. Interestingly, miRNAs are also regulated by oncogenes and TSGs. Considering the entangled regulation, here we propose a new insight into these regulation relationships in cancer: oncogene–miRNA–TSG network, which further emphasizes roles of miRNA, as well as highlights the network regulation among oncogene, miRNA, and TSG during tumorigenesis. The oncogene–miRNA–TSG network demonstrates that oncogenes and TSGs not only show functional synergy, but also there are regulatory relationships among oncogenes and TSGs during tumorigenesis, which could be mediated by miRNAs. In view of the oncogene–miRNA–TSG network involved in many oncogenes, miRNAs, and TSGs, as well as occurring in various tumor types, the anomaly of this network may be a common event in cancers and participates in tumorigenesis. This hypothesis broadens horizons of molecular mechanisms underlying tumorigenesis, and may provide a new promising venue for the prediction, diagnosis, and even therapy of cancer. PMID:28736730

  3. The Oncogenic STP Axis Promotes Triple-Negative Breast Cancer via Degradation of the REST Tumor Suppressor

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    Kristen L. Karlin

    2014-11-01

    Full Text Available Defining the molecular networks that drive breast cancer has led to therapeutic interventions and improved patient survival. However, the aggressive triple-negative breast cancer subtype (TNBC remains recalcitrant to targeted therapies because its molecular etiology is poorly defined. In this study, we used a forward genetic screen to discover an oncogenic network driving human TNBC. SCYL1, TEX14, and PLK1 (“STP axis” cooperatively trigger degradation of the REST tumor suppressor protein, a frequent event in human TNBC. The STP axis induces REST degradation by phosphorylating a conserved REST phospho-degron and bridging REST interaction with the ubiquitin-ligase βTRCP. Inhibition of the STP axis leads to increased REST protein levels and impairs TNBC transformation, tumor progression, and metastasis. Expression of the STP axis correlates with low REST protein levels in human TNBCs and poor clinical outcome for TNBC patients. Our findings demonstrate that the STP-REST axis is a molecular driver of human TNBC.

  4. A Novel Method for Gene-Specific Enhancement of Protein Translation by Targeting 5'UTRs of Selected Tumor Suppressors.

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    Master, Adam; Wójcicka, Anna; Giżewska, Kamilla; Popławski, Piotr; Williams, Graham R; Nauman, Alicja

    2016-01-01

    strategies to enhance expression of proteins including tumor suppressors.

  5. Inhibition of FOXO3 tumor suppressor function by betaTrCP1 through ubiquitin-mediated degradation in a tumor mouse model.

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    Wen-Bin Tsai

    2010-07-01

    Full Text Available The ubiquitin-proteasome system is the primary proteolysis machine for controlling protein stability of the majority of regulatory proteins including those that are critical for cancer development. The forkhead box transcription factor FOXO3 plays a key role in regulating tumor suppression; however, the control of FOXO3 protein stability remains to be established. It is crucial to elucidate the molecular mechanisms underlying the ubiquitin-mediated degradation of FOXO3 tumor suppressor.Here we show that betaTrCP1 oncogenic ubiquitin E3-ligase interacts with FOXO3 and induces its ubiquitin-dependent degradation in an IkappaB kinase-beta phosphorylation dependent manner. Silencing betaTrCP1 augments FOXO3 protein level, resulting in promoting cellular apoptosis in cancer cells. In animal models, increasing FOXO3 protein level by silencing betaTrCP1 suppresses tumorigenesis, whereas decreasing FOXO3 by over-expressing betaTrCP1 promotes tumorigenesis and tumor growth in vivo.This is a unique demonstration that the betaTrCP1-mediated FOXO3 degradation plays a crucial role in tumorigenesis. These findings significantly contribute to understanding of the control of FOXO3 stability in cancer cells and may provide opportunities for developing innovative anticancer therapeutic modalities.

  6. Calcitriol exerts an anti-tumor effect in osteosarcoma by inducing the endoplasmic reticulum stress response.

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    Shimizu, Takatsune; Kamel, Walied A; Yamaguchi-Iwai, Sayaka; Fukuchi, Yumi; Muto, Akihiro; Saya, Hideyuki

    2017-09-01

    Osteosarcoma is the most common type of primary bone tumor, and novel therapeutic approaches for this disease are urgently required. To identify effective agents, we screened a panel of Food and Drug Administration (FDA)-approved drugs in AXT cells, our newly established mouse osteosarcoma line, and identified calcitriol as a candidate compound with therapeutic efficacy for this disease. Calcitriol inhibited cell proliferation in AXT cells by blocking cell cycle progression. From a mechanistic standpoint, calcitriol induced endoplasmic reticulum (ER) stress, which was potentially responsible for downregulation of cyclin D1, activation of p38 MAPK, and intracellular production of reactive oxygen species (ROS). Knockdown of Atf4 or Ddit3 restored cell viability after calcitriol treatment, indicating that the ER stress response was indeed responsible for the anti-proliferative effect in AXT cells. Notably, the ER stress response was induced to a lesser extent in human osteosarcoma than in AXT cells, consistent with the weaker suppressive effect on cell growth in the human cells. Thus, the magnitude of ER stress induced by calcitriol might be an index of its anti-osteosarcoma effect. Although mice treated with calcitriol exhibited weight loss and elevated serum calcium levels, a single dose was sufficient to decrease osteosarcoma tumor size in vivo. Our findings suggest that calcitriol holds therapeutic potential for treatment of osteosarcoma, assuming that techniques to diminish its toxicity could be established. In addition, our results show that calcitriol could still be safely administered to osteosarcoma patients for its original purposes, including treatment of osteoporosis. © 2017 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

  7. [Analysis of loss of heterozygosity of the tumor suppressor genes p53 and BRCA1 in ovarial carcinomas].

    Science.gov (United States)

    Petrović, Bojana; Perović, Milica; Novaković, Ivana; Atanacković, Jasmina; Popović, Branka; Luković, Ljiljana; Petković, Spasoje

    2006-09-01

    Among the genes involved in ovarian carcinogenesis, there has been increased interest in tumor-suppressor genes p53 and BRCA1. Both of the genes make control of cell cycle, DNA repair and apoptosis. The p53 is a "genome guardian" inactivated in more than 50% of human cancers, while BRCA1 mutations are found mostly in breast and ovarian cancer. The aim of this investigation was to establish the frequency of loss of heterozygosity (LOH) in the regions of the genes p53 and BRCA1 in ovarian carcinomas, and to analyze the association of LOH with the disease stage and prognosis. We analyzed 20 patients with a confirmed diagnosis of epithelilal ovarian carcinoma. DNA for molecular-genetic analysis was extracted from the tumor tissue and blood as normal tissue of each person. Microsatellite markers of the regions of genes p53 and BRCA1 were amplified by PCR method. The determination of allelic status of microsatellites and detection of LOH was performed after PAA gel electroforesis. Both of the analyzed microsatellite markers were informative in 13/20 (65%) cases. In the region of gene p53, LOH was established in 4/13 (30.7%) tumors. One of them had histological gradus G1, one had gradus G2, and two of them had gradus G3, while all were with the International Federation of Gynecology and Obstetrics (FIGO) IIIc stage. In the region of gene BRCA1, LOH was detected in 5/13 (38.5%) tumors. Four of them had histological gradus G2, and one had gradus G3, while by the (FIGO) classification one was with stage Ib, one was with stage IIIb, while the three were with stage IlIc. LOH in both of the analyzed regions was detected in one tumor (7.70), with histological gradus G3 and the FIGO IIIc stage. The frequency of LOH in epthelial ovarian carcinomas was 30.7% and 38.5% for p53 and BRCA1 gene regions, respectively. Most of tumors with LOH had histological gradus G2 or G3, and the clinical FIGO stage IIIc, suggesting the association of this occurrence with a later phase of the disease.

  8. Analysis of loss of heterozygosity of the tumor suppressor genes p53 and BRCA1 in ovarial carcinomas

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    Luković Ljiljana

    2006-01-01

    Full Text Available Background/aim: Among the genes involved in ovarian carcinogenesis, there has been increased interest in tumor-suppressor genes p53 and BRCA1. Both of the genes make control of cell cycle, DNA repair and apoptosis. The p53 is a "genome guardian" inactivated in more than 50% of human cancers, while BRCA1 mutations are found mostly in breast and ovarian cancer. The aim of this investigation was to establish the frequency of loss of heterozygosity (LOH in the regions of the genes p53 and BRCA1 in ovarian carcinomas, and to analyze the association of LOH with the disease stage and prognosis. Methods. We analyzed 20 patients with a confirmed diagnosis of epithelilal ovarian carcinoma. DNA for molecular-genetic analysis was extracted from the tumor tissue and blood as normal tissue of each person. Microsatellite markers of the regions of genes p53 and BRCA1 were amplified by PCR method. The determination of allelic status of microsatellites and detection of LOH was performed after PAA gel electroforesis. Results. Both of the analyzed microsatellite markers were informative in 13/20 (65% cases. In the region of gene p53, LOH was established in 4/13 (30.7% tumors. One of them had histological gradus G1, one had gradus G2, and two of them had gradus G3, while all were with the International Federation of Gynecology and Obstetrics (FIGO IIIc stage. In the region of gene BRCA1, LOH was detected in 5/13 (38.5% tumors. Four of them had histological gradus G2, and one had gradus G3, while by the (FIGO classification one was with stage Ib, one was with stage IIIb, while the three were with stage IIIc. LOH in both of the analyzed regions was detected in one tumor (7.7%, with histological gradus G3 and the FIGO IIIc stage. Conclusion. The frequency of LOH in epthelial ovarian carcinomas was 30.7% and 38.5% for p53 and BRCA1 gene regions, respectively. Most of tumors with LOH had histological gradus G2 or G3, and the clinical FIGO stage IIIc, suggesting the

  9. Caffeine Mediates Sustained Inactivation of Breast Cancer-Associated Myofibroblasts via Up-Regulation of Tumor Suppressor Genes

    Science.gov (United States)

    Al-Ansari, Mysoon M.; Aboussekhra, Abdelilah

    2014-01-01

    Background Active cancer-associated fibroblasts (CAFs) or myofibroblasts play important roles not only in the development and progression of breast carcinomas, but also in their prognosis and treatment. Therefore, targeting these cells through suppressing their supportive procarcinogenic paracrine effects is mandatory for improving the current therapies that are mainly targeting tumor cells. To this end, we investigated the effect of the natural and pharmacologically safe molecule, caffeine, on CAF cells and their various procarcinogenic effects. Methodology/Principal Findings We have shown here that caffeine up-regulates the tumor suppressor proteins p16, p21, p53 and Cav-1, and reduces the expression/secretion of various cytokines (IL-6, TGF-β, SDF-1 and MMP-2), and down-regulates α-SMA. Furthermore, caffeine suppressed the migratory/invasiveness abilities of CAF cells through PTEN-dependent Akt/Erk1/2 inactivation. Moreover, caffeine reduced the paracrine pro-invasion/−migration effects of CAF cells on breast cancer cells. These results indicate that caffeine can inactivate breast stromal myofibroblasts. This has been confirmed by showing that caffeine also suppresses the paracrine pro-angiogenic effect of CAF cells through down-regulating HIF-1αand its downstream effector VEGF-A. Interestingly, these effects were sustained in absence of caffeine. Conclusion/Significance The present findings provide a proof of principle that breast cancer myofibroblasts can be inactivated, and thereby caffeine may provide a safe and effective prevention against breast tumor growth/recurrence through inhibition of the procarcinogenic effects of active stromal fibroblasts. PMID:24595168

  10. Caffeine mediates sustained inactivation of breast cancer-associated myofibroblasts via up-regulation of tumor suppressor genes.

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    Mysoon M Al-Ansari

    Full Text Available BACKGROUND: Active cancer-associated fibroblasts (CAFs or myofibroblasts play important roles not only in the development and progression of breast carcinomas, but also in their prognosis and treatment. Therefore, targeting these cells through suppressing their supportive procarcinogenic paracrine effects is mandatory for improving the current therapies that are mainly targeting tumor cells. To this end, we investigated the effect of the natural and pharmacologically safe molecule, caffeine, on CAF cells and their various procarcinogenic effects. METHODOLOGY/PRINCIPAL FINDINGS: We have shown here that caffeine up-regulates the tumor suppressor proteins p16, p21, p53 and Cav-1, and reduces the expression/secretion of various cytokines (IL-6, TGF-β, SDF-1 and MMP-2, and down-regulates α-SMA. Furthermore, caffeine suppressed the migratory/invasiveness abilities of CAF cells through PTEN-dependent Akt/Erk1/2 inactivation. Moreover, caffeine reduced the paracrine pro-invasion/-migration effects of CAF cells on breast cancer cells. These results indicate that caffeine can inactivate breast stromal myofibroblasts. This has been confirmed by showing that caffeine also suppresses the paracrine pro-angiogenic effect of CAF cells through down-regulating HIF-1αand its downstream effector VEGF-A. Interestingly, these effects were sustained in absence of caffeine. CONCLUSION/SIGNIFICANCE: The present findings provide a proof of principle that breast cancer myofibroblasts can be inactivated, and thereby caffeine may provide a safe and effective prevention against breast tumor growth/recurrence through inhibition of the procarcinogenic effects of active stromal fibroblasts.

  11. KLF4 is a novel candidate tumor suppressor gene in pancreatic ductal carcinoma.

    Science.gov (United States)

    Zammarchi, Francesca; Morelli, Mariangela; Menicagli, Michele; Di Cristofano, Claudio; Zavaglia, Katia; Paolucci, Alessandra; Campani, Daniela; Aretini, Paolo; Boggi, Ugo; Mosca, Franco; Cavazzana, Andrea; Cartegni, Luca; Bevilacqua, Generoso; Mazzanti, Chiara Maria

    2011-01-01

    Ductal pancreatic carcinoma (DPC) is a deadly disease with an incidence of 9 cases in 100,000 people per year and a mortality rate close to 100%. Allelic losses in the long arm of chromosome 9 are commonly encountered in many human malignancies but no data are yet available about DPC. We screened 40 laser-microdissected DPC samples and 6 pre-invasive lesions for 9 microsatellite mapping markers of region 9q21.3 through 9q34.2. A small overlapping region of deletion, spanning 8 million base pairs, was identified between D9S127 and D9S105. Two genes, RSG3 and KLF4, mapped to 9q31.1 through 9q32, were further investigated. A highly significant association was found between KLF4 gene expression levels and genomic status. Similarly, absence of immunohistochemical expression of KLF4 protein was found in 86.8% cases of DPC (33/38). Overexpression of KLF4 in a human pancreatic carcinoma cell line induced a significant decrease in the proliferation associated with up-regulation of p21 and the down-regulation of cyclin D1. In conclusion, we identified a novel oncosuppressor region located at the 9q 31.1-3 locus that is lost in DPC at high frequency. Loss of KLF4 expression is closely related to the genomic loss, and its restoration inhibits cancer cell proliferation, suggesting a key suppressor role in pancreatic tumorigenesis. Copyright © 2011 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  12. Enhanced inflammation and attenuated tumor suppressor pathways are associated with oncogene-induced lung tumors in aged mice

    Science.gov (United States)

    Aging is often accompanied by a dramatic increase in cancer susceptibility. To gain insights into how aging affects tumor susceptibility, we generated a conditional mouse model in which oncogenic KrasG12D was activated specifically in lungs of young (3-5 months) and old (19-24 months) mice. Activati...

  13. Epithelial cell-derived periostin functions as a tumor suppressor in gastric cancer through stabilizing p53 and E-cadherin proteins via the Rb/E2F1/p14ARF/Mdm2 signaling pathway.

    Science.gov (United States)

    Lv, Hongjun; Liu, Rui; Fu, Jiao; Yang, Qi; Shi, Jing; Chen, Pu; Ji, Meiju; Shi, Bingyin; Hou, Peng

    2014-01-01

    Periostin is usually considered as an oncogene in diverse human cancers, including breast, prostate, colon, esophagus, and pancreas cancers, whereas it acts as a tumor suppressor in bladder cancer. In gastric cancer, it has been demonstrated that periglandular periostin expression is decreased whereas stromal periostin expression is significantly increased as compared with normal gastric tissues. Moreover, periostin produced by stromal myofibroblasts markedly promotes gastric cancer cell growth. These observations suggest that periostin derived from different types of cells may play distinct biological roles in gastric tumorigenesis. The aim of this study was to explore the biological functions and related molecular mechanisms of epithelial cell-derived periostin in gastric cancer. Our data showed that periglandular periostin was significantly down-regulated in gastric cancer tissues as compared with matched normal gastric mucosa. In addition, its expression in metastatic lymph nodes was significantly lower than that in their primary cancer tissues. Our data also demonstrated that periglandular periostin expression was negatively associated with tumor stage. More importantly, restoration of periostin expression in gastric cancer cells dramatically suppressed cell growth and invasiveness. Elucidation of the mechanisms involved revealed that periostin restoration enhanced Rb phosphorylation and sequentially activated the transcription of E2F1 target gene p14(ARF), leading to Mdm2 inactivation and the stabilization of p53 and E-cadherin proteins. Strikingly, these effects of periostin were abolished upon Rb deletion. Collectively, we have for the first time demonstrated that epithelial cell-derived periostin exerts tumor-suppressor activities in gastric cancer through stabilizing p53 and E-cadherin proteins via the Rb/E2F1/p14(ARF)/Mdm2 signaling pathway.

  14. Evolution and origin of merlin, the product of the Neurofibromatosis type 2 (NF2 tumor-suppressor gene

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    Omelyanchuk Leonid V

    2005-12-01

    Full Text Available Abstract Background Merlin, the product of the Neurofibromatosis type 2 (NF2 tumor suppressor gene, belongs to the ezrin-radixin-moesin (ERM subgroup of the protein 4.1 superfamily, which links cell surface glycoproteins to the actin cytoskeleton. While merlin's functional activity has been examined in mammalian and Drosophila models, little is understood about its evolution, diversity, and overall distribution among different taxa. Results By combining bioinformatic and phylogenetic approaches, we demonstrate that merlin homologs are present across a wide range of metazoan lineages. While the phylogenetic tree shows a monophyletic origin of the ERM family, the origin of the merlin proteins is robustly separated from that of the ERM proteins. The derivation of merlin is thought to be in early metazoa. We have also observed the expansion of the ERM-like proteins within the vertebrate clade, which occurred after its separation from Urochordata (Ciona intestinalis. Amino acid sequence alignment reveals the absence of an actin-binding site in the C-terminal region of all merlin proteins from various species but the presence of a conserved internal binding site in the N-terminal domain of the merlin and ERM proteins. In addition, a more conserved pattern of amino acid residues is found in the region containing the so-called "Blue Box," although some amino acid substitutions in this region exist in the merlin sequences of worms, fish, and Ciona. Examination of sequence variability at functionally significant sites, including the serine-518 residue, the phosphorylation of which modulates merlin's intra-molecular association and function as a tumor suppressor, identifies several potentially important sites that are conserved among all merlin proteins but divergent in the ERM proteins. Secondary structure prediction reveals the presence of a conserved α-helical domain in the central to C-terminal region of the merlin proteins of various species. The

  15. The tumor suppressors p53, p63, and p73 are regulators of microRNA processing complex.

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    Lakshmanane Boominathan

    2010-05-01

    Full Text Available The tumor suppressors p53, p73, and p63 are known to function as transcription factors. They promote either growth arrest or apoptosis, depending upon the DNA damage. A number of microRNAs (miRNAs have been shown to function as transcriptional targets of p53 and they appear to aid p53 in promoting growth arrest and apoptosis. However, the question of p53/p63/p73 regulating the miRNA processing complex has not been addressed in depth so far. Comparative/computational genomic analysis was performed using Target scan, Mami, and Diana software to identify miRNAs that regulate the miRNA processing complex. Here, I present evidence for the first time that the tumor suppressors p53, p63, and p73 function as both positive and negative regulators of the miRNA processing components. Curated p53-dependent miRNA expression data was used to identify p53-miRs that target the components of the miRNA-processing complex. This analysis suggests that most of the components (mRNAs' 3'UTR of the miRNA processing complex are targeted by p53-miRs. Remarkably, this data revealed the conserved nature of p53-miRs in targeting a number of components of the miRNA processing complex. p53/p73/p63 appears to regulate the major components of the miRNA processing, such as Drosha-DGCR8, Dicer-TRBP2, and Argonaute proteins. In particular, p53/p73/p63 appears to regulate the processing of miRNAs, such as let-7, miR-200c, miR-143, miR-107, miR-16, miR-145, miR-134, miR-449a, miR-503, and miR-21. Interestingly, there seems to be a phenotypic similarity between p63(-/- and dicer(-/- mice, suggesting that p63 and dicer could regulate each other. In addition, p63, p73, and the DGCR8 proteins contain a conserved interaction domain. Further, promoters of a number of components of the miRNA processing machinery, including dicer and P2P-R, contain p53-REs, suggesting that they could be direct transcriptional targets of p63/p73/p53. Together, this study provides mechanistic insights into

  16. miR-132 and miR-212 are increased in pancreatic cancer and target the retinoblastoma tumor suppressor

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong-Kook [College of Pharmacy, Ohio State University, Columbus, OH 43210 (United States); Henry, Jon C. [Department of Surgery, Ohio State University, Columbus, OH 43210 (United States); Jiang, Jinmai [College of Pharmacy, Ohio State University, Columbus, OH 43210 (United States); Esau, Christine [Regulus Therapeutics, Carlsbad, CA (United States); Gusev, Yuriy [Lombardi Cancer Center, Georgetown University, Washington, DC (United States); Lerner, Megan R. [Veterans Affairs Medical Center, Oklahoma City, OK (United States); Postier, Russell G. [Department of Surgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK (United States); Brackett, Daniel J. [Veterans Affairs Medical Center, Oklahoma City, OK (United States); Schmittgen, Thomas D., E-mail: Schmittgen.2@osu.edu [College of Pharmacy, Ohio State University, Columbus, OH 43210 (United States)

    2011-03-25

    Research highlights: {yields} The expression of miR-132 and miR-212 are significantly increased in pancreatic cancer. {yields} miR-132 and miR-212 target the tumor suppressor pRb, resulting in enhanced proliferation. {yields} miR-132 and miR-212 expression is increased by a {beta}2 adrenergic receptor agonist, suggesting a novel mechanism for pancreatic cancer progression. -- Abstract: Numerous microRNAs (miRNAs) are reported as differentially expressed in cancer, however the consequence of miRNA deregulation in cancer is unknown for many miRNAs. We report that two miRNAs located on chromosome 17p13, miR-132 and miR-212, are over-expressed in pancreatic adenocarcinoma (PDAC) tissues. Both miRNAs are predicted to target the retinoblastoma tumor suppressor, Rb1. Validation of this interaction was confirmed by luciferase reporter assay and western blot in a pancreatic cancer cell line transfected with pre-miR-212 and pre-miR-132 oligos. Cell proliferation was enhanced in Panc-1 cells transfected with pre-miR-132/-212 oligos. Conversely, antisense oligos to miR-132/-212 reduced cell proliferation and caused a G{sub 2}/M cell cycle arrest. The mRNA of a number of E2F transcriptional targets were increased in cells over expressing miR-132/-212. Exposing Panc-1 cells to the {beta}2 adrenergic receptor agonist, terbutaline, increased the miR-132 and miR-212 expression by 2- to 4-fold. We report that over-expression of miR-132 and miR-212 result in reduced pRb protein in pancreatic cancer cells and that the increase in cell proliferation from over-expression of these miRNAs is likely due to increased expression of several E2F target genes. The {beta}2 adrenergic pathway may play an important role in this novel mechanism.

  17. Identification of PHRF1 as a Tumor Suppressor that Promotes the TGF-β Cytostatic Program through Selective Release of TGIF-Driven PML Inactivation

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    Asma Ettahar

    2013-08-01

    Full Text Available The homeodomain protein TGIF (TG-interacting factor restricts TGF-β/Smad cytostatic signaling by interfering with the nucleocytoplasmic transit of the tumor suppressor cPML. Here, we identify PHRF1 as a ubiquitin ligase that enforces TGIF decay by driving its ubiquitination at lysine 130. In so doing, PHRF1 ensures redistribution of cPML into the cytoplasm, where it associates with SARA and coordinates activation of Smad2 by the TGF-β receptor. The PHRF1 gene resides within the tumor suppressor locus 11p15.5, which displays frequent loss in a wide variety of malignancies, including breast cancer. Remarkably, we found that the PHRF1 gene is deleted or silenced in a high proportion of human breast cancer samples and cancer cell lines. Reconstitution of PHRF1 into deficient cells impeded their propensity to form tumors in vivo, most likely because of the reemergence of TGF-β responsiveness. These findings unveil a paradigm behind inactivation of the cPML tumor suppressor network in human malignancies.

  18. Oncogenic miR-19a and miR-19b co-regulate tumor suppressor MTUS1 to promote cell proliferation and migration in lung cancer

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    Yuanyuan Gu

    2017-03-01

    Full Text Available ABSTRACT MTUS1 (microtubule-associated tumor suppressor 1 has been identified that can function as a tumor suppressor gene in many malignant tumors. However, the function and mechanisms underlying the regulation of MTUS1 are unclear. In the present study, we reported that miR-19a and miR-19b (miR-19a/b promote proliferation and migration of lung cancer cells by targeting MTUS1. First, MTUS1 was proved to function as a tumor suppressor in lung cancer and was linked to cell proliferation and migration promotion. Second, an inverse correlation between miR-19a/b expression and MTUS1 mRNA/protein expression was noted in human lung cancer tissues. Third, MTUS1 was appraised as a direct target of miR-19a/b by bioinformatics analysis. Fourth, direct MTUS1 regulation by miR-19a/b in lung cancer cells was experimentally affirmed by cell transfection assay and luciferase reporter assay. Finally, miR-19a/b were shown to cooperatively repress MTUS1 expression and synergistically regulate MTUS1 expression to promote lung cancer cell proliferation and migration. In conclusion, our findings have provided the first clues regarding the roles of miR-19a/b, which appear to function as oncomirs in lung cancer by downregulating MTUS1.

  19. A functional network of the tumor suppressors APC, hDlg, and PTEN, that relies on recognition of specific PDZ-domains.

    Science.gov (United States)

    Sotelo, Natalia S; Valiente, Miguel; Gil, Anabel; Pulido, Rafael

    2012-08-01

    APC and PTEN are tumor suppressor proteins that bind through their C-termini to the PDZ domain containing-hDlg scaffolding protein. We have found that co-expression of PTEN and hDlg enhanced the negative regulation of the PI3K/Akt pathway by PTEN, indicating the physiologic importance of these interactions. APC and PTEN share other PDZ domain containing-interacting partners, including the MAGI scaffolding proteins and the MAST family of protein kinases. Mutational analysis revealed that the C-terminal PDZ-binding motifs from APC and PTEN were differentially recognized by distinct PDZ domains. APC bound to the three PDZ domains from hDlg, whereas PTEN mainly bound to PDZ-2/hDlg. This indicates the existence of overlapping, but distinct PDZ-domain recognition patterns by APC and PTEN. Furthermore, a ternary complex formed by APC, PTEN, and hDlg was detected, suggesting that hDlg may serve as a platform to bring in proximity APC and PTEN tumor suppressor activities. In line with this, tumor-related mutations targeting the PDZ-2/hDlg domain diminished its interaction with APC and PTEN. Our results expand the PDZ-domain counterparts for the tumor suppressor APC, show that APC and PTEN share PDZ-domain partners but have individual molecular determinants for specific recognition of PDZ domains, and suggest the participation of the tumor suppressors APC, PTEN, and hDlg in PDZ-domain interaction networks which may be relevant in oncogenesis. Copyright © 2012 Wiley Periodicals, Inc.

  20. ETS transcription factors control transcription of EZH2 and epigenetic silencing of the tumor suppressor gene Nkx3.1 in prostate cancer.

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    Paolo Kunderfranco

    2010-05-01

    Full Text Available ETS transcription factors regulate important signaling pathways involved in cell differentiation and development in many tissues and have emerged as important players in prostate cancer. However, the biological impact of ETS factors in prostate tumorigenesis is still debated.We performed an analysis of the ETS gene family using microarray data and real-time PCR in normal and tumor tissues along with functional studies in normal and cancer cell lines to understand the impact in prostate tumorigenesis and identify key targets of these transcription factors. We found frequent dysregulation of ETS genes with oncogenic (i.e., ERG and ESE1 and tumor suppressor (i.e., ESE3 properties in prostate tumors compared to normal prostate. Tumor subgroups (i.e., ERG(high, ESE1(high, ESE3(low and NoETS tumors were identified on the basis of their ETS expression status and showed distinct transcriptional and biological features. ERG(high and ESE3(low tumors had the most robust gene signatures with both distinct and overlapping features. Integrating genomic data with functional studies in multiple cell lines, we demonstrated that ERG and ESE3 controlled in opposite direction transcription of the Polycomb Group protein EZH2, a key gene in development, differentiation, stem cell biology and tumorigenesis. We further demonstrated that the prostate-specific tumor suppressor gene Nkx3.1 was controlled by ERG and ESE3 both directly and through induction of EZH2.These findings provide new insights into the role of the ETS transcriptional network in prostate tumorigenesis and uncover previously unrecognized links between aberrant expression of ETS factors, deregulation of epigenetic effectors and silencing of tumor suppressor genes. The link between aberrant ETS activity and epigenetic gene silencing may be relevant for the clinical management of prostate cancer and design of new therapeutic strategies.

  1. A targeted constitutive mutation in the APC tumor suppressor gene underlies mammary but not intestinal tumorigenesis.

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    Claudia Gaspar

    2009-07-01

    Full Text Available Germline mutations in the adenomatous polyposis coli (APC gene are responsible for familial adenomatous polyposis (FAP, an autosomal dominant hereditary predisposition to the development of multiple colorectal adenomas and of a broad spectrum of extra-intestinal tumors. Moreover, somatic APC mutations play a rate-limiting and initiating role in the majority of sporadic colorectal cancers. Notwithstanding its multifunctional nature, the main tumor suppressing activity of the APC gene resides in its ability to regulate Wnt/beta-catenin signaling. Notably, genotype-phenotype correlations have been established at the APC gene between the length and stability of the truncated proteins encoded by different mutant alleles, the corresponding levels of Wnt/beta-catenin signaling activity they encode for, and the incidence and distribution of intestinal and extra-intestinal tumors. Here, we report a novel mouse model, Apc1572T, obtained by targeting a truncated mutation at codon 1572 in the endogenous Apc gene. This hypomorphic mutant allele results in intermediate levels of Wnt/beta-catenin signaling activation when compared with other Apc mutations associated with multifocal intestinal tumors. Notwithstanding the constitutive nature of the mutation, Apc(+/1572T mice have no predisposition to intestinal cancer but develop multifocal mammary adenocarcinomas and subsequent pulmonary metastases in both genders. The histology of the Apc1572T primary mammary tumours is highly heterogeneous with luminal, myoepithelial, and squamous lineages and is reminiscent of metaplastic carcinoma of the breast in humans. The striking phenotype of Apc(+/1572T mice suggests that specific dosages of Wnt/beta-catenin signaling activity differentially affect tissue homeostasis and initiate tumorigenesis in an organ-specific fashion.

  2. The Role of Tumor Metastases Suppressor Gene, Drg-1, in Breast Cancer

    Science.gov (United States)

    2007-03-01

    ceramide level in the tumor cells, and this increase was abrogated by acetyl-CoA carboxylase inhibitor. In addition, carnitine palmitoyltransferase-1...acetyl-CoA carboxylase inhibitor), fumonisin B1 (ceramide synthase inhibitor), etomoxir [ carnitine palmitoyltransferase-1 (CPT-1) inhibitor], and C2...enzyme CPT-1 that transesterifies long-chain acyl-CoAs to acylcarnitine, permitting their entry into the mitochondria for fatty acid oxidation (15). It

  3. The Role of Tumor Metastases Suppressor Gene, Drg-1, in Breast Cancer

    Science.gov (United States)

    2009-03-01

    regulates NM23 in hepatocarcinoma cells. Increased adhesion to ECM in vitro Inhibits the growth of xenograft tumors and gastric cancer cell metastasis to...expression of NM23 was also shown to be up-regulated by ATRA in human hepatocarcinoma cell line and gastric cancer cell lines [226,227]. Liu et al...invasion of human hepatocarcinoma cell line [226]. Furthermore, Wu et al. examined the effect of ATRA treatment in xenografted nude mice and found that

  4. Genetic interactions between the Drosophila tumor suppressor gene ept and the stat92E transcription factor.

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    M Melissa Gilbert

    2009-09-01

    Full Text Available Tumor Susceptibility Gene-101 (TSG101 promotes the endocytic degradation of transmembrane proteins and is implicated as a mutational target in cancer, yet the effect of TSG101 loss on cell proliferation in vertebrates is uncertain. By contrast, Drosophila epithelial tissues lacking the TSG101 ortholog erupted (ept develop as enlarged undifferentiated tumors, indicating that the gene can have anti-growth properties in a simple metazoan. A full understanding of pathways deregulated by loss of Drosophila ept will aid in understanding potential links between mammalian TSG101 and growth control.We have taken a genetic approach to the identification of pathways required for excess growth of Drosophila eye-antennal imaginal discs lacking ept. We find that this phenotype is very sensitive to the genetic dose of stat92E, the transcriptional effector of the Jak-Stat signaling pathway, and that this pathway undergoes strong activation in ept mutant cells. Genetic evidence indicates that stat92E contributes to cell cycle deregulation and excess cell size phenotypes that are observed among ept mutant cells. In addition, autonomous Stat92E hyper-activation is associated with altered tissue architecture in ept tumors and an effect on expression of the apical polarity determinant crumbs.These findings identify ept as a cell-autonomous inhibitor of the Jak-Stat pathway and suggest that excess Jak-Stat signaling makes a significant contribution to proliferative and tissue architectural phenotypes that occur in ept mutant tissues.

  5. Oncogene activation and tumor suppressor gene inactivation find their sites of expression in the changes in time and space of the age-adjusted cancer incidence rate.

    Science.gov (United States)

    Kodama, M; Kodama, T; Murakami, M

    2000-01-01

    The purpose of the present investigation is to elucidate the relation between the distribution pattern of the age-adjusted incidence rate (AAIR) changes in time and space of 15 tumors of bothe sexes and the locations of centers of centripetal-(oncogene type) and centrifugal-(tumoe suppressor gene type) forces. The fitness of the observed log AAIR data sets to the oncogene type- and the tumor suppressor gene type-equilibrium models and the locations of 2 force centers were calculated by applying the least square method of Gauss to log AAIR pair data series with and without topological data manipulations, which are so designed as to let log AAIR pair data series fit to 2 variant (x, y) frameworks, the Rect-coordinates and the Para-coordinates. The 2 variant (x, y) coordinates are defined each as an (x, y) framework with its X axis crossed at a right angle to the regression line of the original log AAIR data (the Rect-coordinates) and as another framework with its X axis run in parallel with the regression line of the original log AAIR pair data series (the Para-coordinates). The fitness test of log AAIR data series to either the oncogene activation type equilibrium model (r = -1.000) or the tumor suppressor gene inactivation type (r = 1.000) was conducted for each of the male-female type pair data and the female-male type data, for each of log AAIR changes in space and log AAIR changes in time, and for each of the 3 (x, y) frameworks in a given neoplasia of both sexes. The results obtained are given as follows: 1) The positivity rates of the fitness test to the oncogene type equilibrium model and the tumor suppressor gene type model were each 63.3% and 56.7% with the log AAIR changes in space, and 73.3% and 73.3% with log AAIR changes in time, as tested in 15 human neoplasias of both sexes. 2) Evidence was presented to indicate that the clearance of oncogene activation and tumor suppressor gene inactivation is the sine qua non premise of carciniogenesis. 3) The r

  6. The effect of age at exposure on the inactivating mechanisms and relative contributions of key tumor suppressor genes in radiation-induced mouse T-cell lymphomas

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    Sunaoshi, Masaaki [Radiobiology for Children' s Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Department of Biological Sciences, College of Science, Ibaraki University, Bunkyo 2-1-1, Mito, Ibaraki 310-8512 (Japan); Amasaki, Yoshiko; Hirano-Sakairi, Shinobu; Blyth, Benjamin J. [Radiobiology for Children' s Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Morioka, Takamitsu [Radiobiology for Children' s Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Radiation Effect Accumulation and Prevention Project, Fukushima Project Headquarters, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Kaminishi, Mutsumi [Radiobiology for Children' s Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Shang, Yi [Radiation Effect Accumulation and Prevention Project, Fukushima Project Headquarters, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Nishimura, Mayumi; Shimada, Yoshiya [Radiobiology for Children' s Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Radiation Effect Accumulation and Prevention Project, Fukushima Project Headquarters, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Tachibana, Akira [Department of Biological Sciences, College of Science, Ibaraki University, Bunkyo 2-1-1, Mito, Ibaraki 310-8512 (Japan); and others

    2015-09-15

    Highlights: • T-cell lymphoma incidence, latency and weight did not change with age at exposure. • Lymphomas had frequent loss of heterozygosity on chromosomes 4, 11 and 19. • These lesions targeted the Cdkn2a, Ikaros and Pten tumor suppressor genes. • Age at exposure may influence which tumor suppressor genes are lost in each tumor. • The mechanisms of tumor suppressor gene loss were different at each locus. - Abstract: Children are considered more sensitive to radiation-induced cancer than adults, yet any differences in genomic alterations associated with age-at-exposure and their underlying mechanisms remain unclear. We assessed genome-wide DNA copy number and mutation of key tumor suppressor genes in T-cell lymphomas arising after weekly irradiation of female B6C3F1 mice with 1.2 Gy X-rays for 4 consecutive weeks starting during infancy (1 week old), adolescence (4 weeks old) or as young adults (8 weeks old). Although T-cell lymphoma incidence was similar, loss of heterozygosity at Cdkn2a on chromosome 4 and at Ikaros on chromosome 11 was more frequent in the two older groups, while loss at the Pten locus on chromosome 19 was more frequent in the infant-irradiated group. Cdkn2a and Ikaros mutation/loss was a common feature of the young adult-irradiation group, with Ikaros frequently (50%) incurring multiple independent hits (including deletions and mutations) or suffering a single hit predicted to result in a dominant negative protein (such as those lacking exon 4, an isoform we have designated Ik12, which lacks two DNA binding zinc-finger domains). Conversely, Pten mutations were more frequent after early irradiation (60%) than after young adult-irradiation (30%). Homozygous Pten mutations occurred without DNA copy number change after irradiation starting in infancy, suggesting duplication of the mutated allele by chromosome mis-segregation or mitotic recombination. Our findings demonstrate that while deletions on chromosomes 4 and 11 affecting Cdkn2

  7. A mutation in the neurofibromatosis type 2 tumor-suppressor gene, giving rise to widely different clinical phenotypes in two unrelated individuals

    Energy Technology Data Exchange (ETDEWEB)

    Bourn, D.; Carter, S.A.; Goodship, J.; Strachan, T. (Univ. of Newcastle upon Tyne (United Kingdom)); Evans, G.R.; Coakham, H.

    1994-07-01

    The authors have sought mutations in the recently identified neurofibromatosis type 2 (NF2) tumor-suppressor gene in a large panel of NF2 patients, using PCR-based SSCP and heteroduplex analysis, followed by cloning and sequencing of appropriate PCR products. Two unrelated NF2 patients were found to have identical nonsense mutations caused by a C-to-T transition in a CpG dinucleotide that is a potential mutational hot spot in the NF2 tumor-suppressor gene. Unexpectedly, the two individuals had widely different clinical phenotypes, representing the severe Wishart and mild Gardner clinical subtypes. Analysis of DNA samples from different tissues of the mildly affected patient suggests that he is a somatic mosaic for the mutation. 26 refs., 3 figs.

  8. MiR-206 functions as a tumor suppressor and directly targets K-Ras in human oral squamous cell carcinoma [Retraction

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    Lin FO

    2016-10-01

    Full Text Available The Editor-in-Chief and Publisher of OncoTargets and Therapy have been alerted to unacceptable levels of duplication with another published paper: Zhang D, Ni Z, Xu X, and Xiao J. MiR-32 Functions as a Tumor Suppressor and Directly Targets EZH2 in Human Oral Squamous Cell Carcinoma. Medical Science Monitor. 20:2527–2535, 2014.Accordingly, we retract Lin FO, Yao LJ, Xiao J, Liu DF, and Ni ZY. MiR-206 functions as a tumor suppressor and directly targets K-Ras in human oral squamous cell carcinoma. OncoTargets and Therapy. 2014;7:1583–1591.This Retraction relates to 

  9. The Tumor Suppressor Smad4/DPC4 Is Regulated by Phosphorylations that Integrate FGF, Wnt, and TGF-β Signaling

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    Hadrien Demagny

    2014-10-01

    Full Text Available Smad4 is a major tumor suppressor currently thought to function constitutively in the transforming growth factor β (TGF-β-signaling pathway. Here, we report that Smad4 activity is directly regulated by the Wnt and fibroblast growth factor (FGF pathways through GSK3 and mitogen-activated protein kinase (MAPK phosphorylation sites. FGF activates MAPK, which primes three sequential GSK3 phosphorylations that generate a Wnt-regulated phosphodegron bound by the ubiquitin E3 ligase β-TrCP. In the presence of FGF, Wnt potentiates TGF-β signaling by preventing Smad4 GSK3 phosphorylations that inhibit a transcriptional activation domain located in the linker region. When MAPK is not activated, the Wnt and TGF-β signaling pathways remain insulated from each other. In Xenopus embryos, these Smad4 phosphorylations regulate germ-layer specification and Spemann organizer formation. The results show that three major signaling pathways critical in development and cancer are integrated at the level of Smad4.

  10. An unexpected inhibition of antiviral signaling by virus-encoded tumor suppressor p53 in pancreatic cancer cells

    Science.gov (United States)

    Hastie, Eric; Cataldi, Marcela; Steuerwald, Nury; Grdzelishvili, Valery Z.

    2015-01-01

    Virus-encoded tumor suppressor p53 transgene expression has been successfully used in vesicular stomatitis virus (VSV) and other oncolytic viruses (OVs) to enhance their anticancer activities. However, p53 is also known to inhibit virus replication via enhanced type I interferon (IFN) antiviral responses. To examine whether p53 transgenes enhance antiviral signaling in human pancreatic ductal adenocarcinoma (PDAC) cells, we engineered novel VSV recombinants encoding human p53 or the previously described chimeric p53-CC, which contains the coiled-coil (CC) domain from breakpoint cluster region (BCR) protein and evades the dominant-negative activities of endogenously expressed mutant p53. Contrary to an expected enhancement of antiviral signaling by p53, our global analysis of gene expression in PDAC cells showed that both p53 and p53-CC dramatically inhibited type I IFN responses. Our data suggest that this occurs through p53-mediated inhibition of the NF-κB pathway. Importantly, VSV-encoded p53 or p53-CC did not inhibit antiviral signaling in non-malignant human pancreatic ductal cells, which retain their resistance to all VSV recombinants. To the best of our knowledge, this is the first report of p53-mediated inhibition of antiviral signaling, and it suggests that OV-encoded p53 can simultaneously produce anticancer activities while assisting, rather than inhibiting, virus replication in cancer cells. PMID:25965802

  11. Sumoylation of the Tumor Suppressor Promyelocytic Leukemia Protein Regulates Arsenic Trioxide-Induced Collagen Synthesis in Osteoblasts

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    Wen-Xiao Xu

    2015-11-01

    Full Text Available Background/Aims: Promyelocytic leukemia (PML protein is a tumor suppressor that fuses with retinoic acid receptor-α (PML-RARα to contribute to the initiation of acute promyelocytic leukemia (APL. Arsenic trioxide (ATO upregulates expression of TGF-β1, promoting collagen synthesis in osteoblasts, and ATO binds directly to PML to induce oligomerization, sumoylation, and ubiquitination. However, how ATO upregulates TGF-β1 expression is uncertain. Thus, we suggested that PML sumoylation is responsible for regulation of TGF-β1 protein expression. Methods: Kunming mice were treated with ATO, and osteoblasts were counted under scanning electron microscopy. Masson's staining was used to quantify collagen content. hFOB1.19 cells were transfected with siRNA against UBC9 or RNF4, and then treated with ATO or FBS. TGF-β1, PML expression, and sumoylation were quantified with Western blot, and collagen quantified via immunocytochemistry. Results: ATO enhanced osteoblast accumulation, collagen synthesis, and PML-NB formation in vivo. Knocking down UBC9 in hFOB1.19 cells inhibited ATO- and FBS-induced PML sumoylation, TGF-β1 expression, and collagen synthesis. Conversely, knocking down RNF4 enhanced ATO- and FBS-induced PML sumoylation, TGF-β1 expression, and collagen synthesis. Conclusion: These data suggest that PML sumoylation is required for ATO-induced collagen synthesis in osteoblasts.

  12. Disruption of the PHRF1 Tumor Suppressor Network by PML-RARα Drives Acute Promyelocytic Leukemia Pathogenesis

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    Céline Prunier

    2015-02-01

    Full Text Available PHRF1 functions as an essential component of the TGF-β tumor suppressor pathway by triggering degradation of the homeodomain repressor factor TGIF. This leads to redistribution of cPML into the cytoplasm, where it coordinates phosphorylation and activation of Smad2 by the TGF-β receptor. In acute promyelocytic leukemia (APL, acquisition of PML-RARα is known to impede critical aspects of TGF-β signaling, including myeloid differentiation. Although these defects are thought to rely on suppression of cPML activity, the mechanisms underlying this phenomenon remain enigmatic. Here, we find that an abnormal function of PML-RARα is to interfere with TGIF breakdown, presumably by competing with PHRF1 for binding to TGIF, culminating in cPML sequestration and inactivation. Enforcing PHRF1 activity is sufficient to restore TGF-β cytostatic signaling in human blasts and suppress APL formation in a mouse model of APL, providing proof-of-concept data that suppression of PHRF1 activity by PML-RARα represents a critical determinant in APL pathogenesis.

  13. Disruption of the PHRF1 Tumor Suppressor Network by PML-RARα Drives Acute Promyelocytic Leukemia Pathogenesis

    Science.gov (United States)

    Prunier, Céline; Zhang, Ming-Zhu; Kumar, Santosh; Levy, Laurence; Ferrigno, Olivier; Tzivion, Guri; Atfi, Azeddine

    2015-01-01

    SUMMARY PHRF1 functions as an essential component of the TGF-β tumor suppressor pathway by triggering degradation of the homeodomain transcription factor TGIF. This leads to redistribution of cPML into the cytoplasm, where it coordinates phosphorylation and activation of Smad2 by the TGF-β receptor. In acute promyelocytic leukemia (APL), acquisition of PML-RARα is known to impede critical aspects of TGF-β signaling, including myeloid differentiation. Although these defects are thought to rely on suppression of cPML activity, the mechanisms underlying this phenomenon remain enigmatic. Here, we find that an abnormal function of PML-RARα is to interfere with TGIF breakdown, presumably by competing with PHRF1 for binding to TGIF, culminating in cPML sequestration and inactivation. Enforcing PHRF1 activity is sufficient to restore TGF-β cytostatic signaling in human blasts and suppress APL formation in a mouse model of APL, providing proof-of-concept data that suppression of PHRF1 activity by PML-RARα represents a critical determinant in APL pathogenesis. PMID:25683711

  14. The NF2 tumor suppressor, Merlin, regulates epidermal development through the establishment of a junctional polarity complex.

    Science.gov (United States)

    Gladden, Andrew B; Hebert, Alan M; Schneeberger, Eveline E; McClatchey, Andrea I

    2010-11-16

    The neurofibromatosis type 2 (NF2) tumor suppressor, Merlin, is a FERM (Four point one, Ezrin, Radixin, Moesin) domain-containing protein whose loss results in defective morphogenesis and tumorigenesis in multiple tissues. Like the closely related ERM proteins (Ezrin, Radixin, and Moesin), Merlin may organize the plasma membrane by assembling membrane protein complexes and linking them to the cortical actin cytoskeleton. We previously found that Merlin is a critical mediator of contact-dependent inhibition of proliferation and is required for the establishment of stable adherens junctions (AJs) in cultured cells. Here, we delineate the molecular function of Merlin in AJ establishment in epidermal keratinocytes in vitro and confirm that a role in AJ establishment is an essential function of Merlin in vivo. Our studies reveal that Merlin can associate directly with α-catenin and link it to Par3, thereby providing an essential link between the AJ and the Par3 polarity complex during junctional maturation. Copyright © 2010 Elsevier Inc. All rights reserved.

  15. Molecular conformation of the full-length tumor suppressor NF2/Merlin—a small angle neutron scattering study

    Science.gov (United States)

    Khajeh, Jahan Ali; Ju, Jeong Ho; Atchiba, Moussoubaou; Allaire, Marc; Stanley, Christopher; Heller, William T.; Callaway, David J.E.; Bu, Zimei

    2014-01-01

    Summary The tumor suppressor protein Merlin inhibits cell proliferation upon establishing cell-cell contacts. Because Merlin has high sequence similarity to the Ezrin-Radixin-Moesin (ERM) family of proteins, the structural model of ERM protein autoinhibition and cycling between closed/resting and open/active conformational states is often employed to explain Merlin function. However, recent biochemical studies suggest alternative molecular models of Merlin function. Here, we have determined the low resolution molecular structure and binding activity of Merlin and a Merlin(S518D) mutant that mimics the inactivating phosphorylation at S518 using small angle neutron scattering (SANS) and binding experiments. SANS shows that in solution both Merlin and Merlin(S518D) adopt a closed conformation, but binding experiments indicate that a significant fraction of either Merlin or Merlin(S518D) is capable of binding to the target protein NHERF1. Upon binding to the phosphatidylinositol 4,5-bisphosphate lipid, the wild-type Merlin adopts a more open conformation than in solution, but Merlin(S518D) remains in a closed conformation. This study supports a rheostat model of Merlin in NHERF1 binding, and contributes to resolve a controversy about the molecular conformation and binding activity of Merlin. PMID:24882693

  16. Spatial organization of Hippo signaling at the plasma membrane mediated by the tumor suppressor Merlin/NF2.

    Science.gov (United States)

    Yin, Feng; Yu, Jianzhong; Zheng, Yonggang; Chen, Qian; Zhang, Nailing; Pan, Duojia

    2013-09-12

    Although Merlin/NF2 was discovered two decades ago as a tumor suppressor underlying Neurofibromatosis type II, its precise molecular mechanism remains poorly understood. Recent studies in Drosophila revealed a potential link between Merlin and the Hippo pathway by placing Merlin genetically upstream of the kinase Hpo/Mst. In contrast to the commonly depicted linear model of Merlin functioning through Hpo/Mst, here we show that in both Drosophila and mammals, Merlin promotes downstream Hippo signaling without activating the intrinsic kinase activity of Hpo/Mst. Instead, Merlin directly binds and recruits the effector kinase Wts/Lats to the plasma membrane. Membrane recruitment, in turn, promotes Wts phosphorylation by the Hpo-Sav kinase complex. We further show that disruption of the actin cytoskeleton promotes Merlin-Wts interactions, which implicates Merlin in actin-mediated regulation of Hippo signaling. Our findings elucidate an important molecular function of Merlin and highlight the plasma membrane as a critical subcellular compartment for Hippo signal transduction. Copyright © 2013 Elsevier Inc. All rights reserved.

  17. Molecular conformation of the full-length tumor suppressor NF2/Merlin--a small-angle neutron scattering study.

    Science.gov (United States)

    Ali Khajeh, Jahan; Ju, Jeong Ho; Atchiba, Moussoubaou; Allaire, Marc; Stanley, Christopher; Heller, William T; Callaway, David J E; Bu, Zimei

    2014-07-29

    The tumor suppressor protein Merlin inhibits cell proliferation upon establishing cell-cell contacts. Because Merlin has high level of sequence similarity to the Ezrin-Radixin-Moesin family of proteins, the structural model of Ezrin-Radixin-Moesin protein autoinhibition and cycling between closed/resting and open/active conformational states is often employed to explain Merlin function. However, recent biochemical studies suggest alternative molecular models of Merlin function. Here, we have determined the low-resolution molecular structure and binding activity of Merlin and a Merlin(S518D) mutant that mimics the inactivating phosphorylation at S518 using small-angle neutron scattering and binding experiments. Small-angle neutron scattering shows that, in solution, both Merlin and Merlin(S518D) adopt a closed conformation, but binding experiments indicate that a significant fraction of either Merlin or Merlin(S518D) is capable of binding to the target protein NHERF1. Upon binding to the phosphatidylinositol 4,5-bisphosphate lipid, the wild-type Merlin adopts a more open conformation than in solution, but Merlin(S518D) remains in a closed conformation. This study supports a rheostat model of Merlin in NHERF1 binding and contributes to resolving a controversy about the molecular conformation and binding activity of Merlin. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Cystic Fibrosis Transmembrane Conductance Regulator Attaches Tumor Suppressor PTEN to the Membrane and Promotes Anti Pseudomonas aeruginosa Immunity.

    Science.gov (United States)

    Riquelme, Sebastián A; Hopkins, Benjamin D; Wolfe, Andrew L; DiMango, Emily; Kitur, Kipyegon; Parsons, Ramon; Prince, Alice

    2017-12-19

    The tumor suppressor PTEN controls cell proliferation by regulating phosphatidylinositol-3-kinase (PI3K) activity, but the participation of PTEN in host defense against bacterial infection is less well understood. Anti-inflammatory PI3K-Akt signaling is suppressed in patients with cystic fibrosis (CF), a disease characterized by hyper-inflammatory responses to airway infection. We found that Ptenl-/- mice, which lack the NH2-amino terminal splice variant of PTEN, were unable to eradicate Pseudomonas aeruginosa from the airways and could not generate sufficient anti-inflammatory PI3K activity, similar to what is observed in CF. PTEN and the CF transmembrane conductance regulator (CFTR) interacted directly and this interaction was necessary to position PTEN at the membrane. CF patients under corrector-potentiator therapy, which enhances CFTR transport to the membrane, have increased PTEN amounts. These findings suggest that improved CFTR trafficking could enhance P. aeruginosa clearance from the CF airway by activating PTEN-mediated anti-bacterial responses and might represent a therapeutic strategy. Published by Elsevier Inc.

  19. Evolutionary history of the reprimo tumor suppressor gene family in vertebrates with a description of a new reprimo gene lineage.

    Science.gov (United States)

    Wichmann, Ignacio A; Zavala, Kattina; Hoffmann, Federico G; Vandewege, Michael W; Corvalán, Alejandro H; Amigo, Julio D; Owen, Gareth I; Opazo, Juan C

    2016-10-10

    Genes related to human diseases should be natural targets for evolutionary studies, since they could provide clues regarding the genetic bases of pathologies and potential treatments. Here we studied the evolution of the reprimo gene family, a group of tumor-suppressor genes that are implicated in p53-mediated cell cycle arrest. These genes, especially the reprimo duplicate located on human chromosome 2, have been associated with epigenetic modifications correlated with transcriptional silencing and cancer progression. We demonstrate the presence of a third reprimo lineage that, together with the reprimo and reprimo-like genes, appears to have been differentially retained during the evolutionary history of vertebrates. We present evidence that these reprimo lineages originated early in vertebrate evolution and expanded as a result of the two rounds of whole genome duplications that occurred in the last common ancestor of vertebrates. The reprimo gene has been lost in birds, and the third reprimo gene lineage has been retained in only a few distantly related species, such as coelacanth and gar. Expression analyses revealed that the reprimo paralogs are mainly expressed in the nervous system. Different vertebrate lineages have retained different reprimo paralogs, and even in species that have retained multiple copies, only one of them is heavily expressed. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Activation of the Tumor Suppressor PP2A Emerges as a Potential Therapeutic Strategy for Treating Prostate Cancer

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    Ion Cristóbal

    2015-05-01

    Full Text Available Protein phosphatase 2A (PP2A is a tumor suppressor complex that has recently been reported as a novel and highly relevant molecular target in prostate cancer (PCa. However, its potential therapeutic value remains to be fully clarified. We treated PC-3 and LNCaP cell lines with the PP2A activators forskolin and FTY720 alone or combined with the PP2A inhibitor okadaic acid. We examined PP2A activity, cell growth, prostasphere formation, levels of PP2A phosphorylation, CIP2A and SET expression, and AKT and ERK activation. Interestingly, both forskolin and FTY720 dephosphorylated and activated PP2A, impairing proliferation and prostasphere formation and inducing changes in AKT and ERK phosphorylation. Moreover, FTY720 led to reduced CIP2A levels. Treatment with okadaic acid impaired PP2A activation thus demonstrating the antitumoral PP2A-dependent mechanism of action of both forskolin and FTY720. Levels of PP2A phosphorylation together with SET and CIP2A protein expression were studied in 24 PCa patients and both were associated with high Gleason scores and presence of metastatic disease. Altogether, our results suggest that PP2A inhibition could be involved in PCa progression, and the use of PP2A-activating drugs might represent a novel alternative therapeutic strategy for treating PCa patients.

  1. The MicroRNA-217 Functions as a Potential Tumor Suppressor in Gastric Cancer by Targeting GPC5.

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    Hui Wang

    Full Text Available Gastric cancer (GC is one of the most common malignancies worldwide. Emerging evidence has shown that aberrant expression of microRNAs (miRNAs plays important roles in cancer progression. However, little is known about the potential role of miR-217 in GC. In this study, we investigated the role of miR-217 on GC cell proliferation and invasion. The expression of miR-217 was down-regulated in GC cells and human GC tissues. Enforced expression of miR-217 inhibited GC cells proliferation and invasion. Moreover, Glypican-5 (GPC5, a new ocncogene, was identified as the potential target of miR-217. In addition, overexpression of miR-217 impaired GPC5-induced promotion of proliferation and invasion in GC cells. In conclusion, these findings revealed that miR-217 functioned as a tumor suppressor and inhibited the proliferation and invasion of GC cells by targeting GPC5, which might consequently serve as a therapeutic target for GC patients.

  2. Structure-function analysis of the retinoblastoma tumor suppressor protein – is the whole a sum of its parts?

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    Dick Frederick A

    2007-09-01

    Full Text Available Abstract Biochemical analysis of the retinoblastoma protein's function has received considerable attention since it was cloned just over 20 years ago. During this time pRB has emerged as a key regulator of the cell division cycle and its ability to block proliferation is disrupted in the vast majority of human cancers. Much has been learned about the regulation of E2F transcription factors by pRB in the cell cycle. However, many questions remain unresolved and researchers continue to explore this multifunctional protein. In particular, understanding how its biochemical functions contribute to its role as a tumor suppressor remains to be determined. Since pRB has been shown to function as an adaptor molecule that links different proteins together, or to particular promoters, analyzing pRB by disrupting individual protein interactions holds tremendous promise in unraveling the intricacies of its function. Recently, crystal structures have reported how pRB interacts with some of its molecular partners. This information has created the possibility of rationally separating pRB functions by studying mutants that disrupt individual binding sites. This review will focus on literature that investigates pRB by isolating functions based on binding sites within the pocket domain. This article will also discuss the prospects for using this approach to further explore the unknown functions of pRB.

  3. Frameshift mutations of a tumor suppressor gene ZNF292 in gastric and colorectal cancers with high microsatellite instability.

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    Lee, Ju Hwa; Song, Sang Yong; Kim, Min Sung; Yoo, Nam Jin; Lee, Sug Hyung

    2016-07-01

    A transcription factor-encoding gene ZNF292 is considered a candidate tumor suppressor gene (TSG). Its mutations have been identified in cancers from liver, colon, and bone marrow. However, ZNF292 inactivating mutations that might suppress the TSG functions have not been reported in gastric (GC) and colorectal cancers (CRC) with microsatellite instability (MSI). In a public database, we found that ZNF292 gene had mononucleotide repeats in the coding sequences that might be mutation targets in the cancers with MSI. In this study, we analyzed 79 GCs and 124 CRCs including high MSI (MSI-H) and microsatellite stable/low MSI (MSS/MSI-L) cases for the detection of somatic mutations in the repeats. Overall, we identified frameshift mutations of ZNF292 in 3 (8.8%) GCs and 11 (13.9%) CRCs with MSI-H (14/113), but not in MSS/MSI-L cancers (0/90) (p < 0.001). Also, we studied intratumoral heterogeneity (ITH) of the ZNF292 frameshift mutations in 16 CRCs and found that two (12.5%) had regional ITH of the mutations. Our data show that ZNF292 gene harbors not only frameshift mutations but also mutational ITH, which together may be features of GC and CRC with MSI-H. Based on this, the ZNF292 frameshift mutations may possibly contribute to tumorigenesis by altering its TSG functions in GC and CRC. © 2016 APMIS. Published by John Wiley & Sons Ltd.

  4. An unexpected inhibition of antiviral signaling by virus-encoded tumor suppressor p53 in pancreatic cancer cells.

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    Hastie, Eric; Cataldi, Marcela; Steuerwald, Nury; Grdzelishvili, Valery Z

    2015-09-01

    Virus-encoded tumor suppressor p53 transgene expression has been successfully used in vesicular stomatitis virus (VSV) and other oncolytic viruses (OVs) to enhance their anticancer activities. However, p53 is also known to inhibit virus replication via enhanced type I interferon (IFN) antiviral responses. To examine whether p53 transgenes enhance antiviral signaling in human pancreatic ductal adenocarcinoma (PDAC) cells, we engineered novel VSV recombinants encoding human p53 or the previously described chimeric p53-CC, which contains the coiled-coil (CC) domain from breakpoint cluster region (BCR) protein and evades the dominant-negative activities of endogenously expressed mutant p53. Contrary to an expected enhancement of antiviral signaling by p53, our global analysis of gene expression in PDAC cells showed that both p53 and p53-CC dramatically inhibited type I IFN responses. Our data suggest that this occurs through p53-mediated inhibition of the NF-κB pathway. Importantly, VSV-encoded p53 or p53-CC did not inhibit antiviral signaling in non-malignant human pancreatic ductal cells, which retained their resistance to all tested VSV recombinants. To the best of our knowledge, this is the first report of p53-mediated inhibition of antiviral signaling, and it suggests that OV-encoded p53 can simultaneously produce anticancer activities while assisting, rather than inhibiting, virus replication in cancer cells. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Tumor suppressor microRNA-27a in colorectal carcinogenesis and progression by targeting SGPP1 and Smad2.

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    Yonghua Bao

    Full Text Available The aberrant expression of microRNAs (miRNAs is associated with colorectal carcinogenesis, but the underlying mechanisms are not clear. This study showed that the miRNA-27a (miR-27a was significantly reduced in colorectal cancer tissues and colorectal cancer cell lines, and that the reduced miR-27a was associated with distant metastasis and colorectal cancer clinical pathological stages-miR-27a was lower at stages III/IV than that at stage II. Bioinformatic and systemic biological analysis predicted several targets of miR-27a, among them SGPP1 and Smad2 were significantly affected. SGPP1 and Smad2 at mRNA and protein levels were negatively correlated with miR-27a in human colorectal cancer tissues and cancer cell lines. Increased miR-27a significantly repressed SGPP1 and Smad2 at transcriptional and translational levels. Functional studies showed that increasing miR-27a inhibited colon cancer cell proliferation, promoted apoptosis and attenuated cell migration, which were also linked to downregulation of p-STAT3 and upregulation of cleaved caspase 3. In vivo, miR-27a inhibited colon cancer cell growth in tumor-bearing mice. Taken together, this study has revealed miR-27a as a tumor suppressor and has identified SGPP1 and Smad2 as novel targets of miR-27a, linking to STAT3 for regulating cancer cell proliferation, apoptosis and migration in colorectal cancer. Therefore, miR-27a could be a useful biomarker for monitoring colorectal cancer development and progression, and also could have a therapeutic potential by targeting SGPP1, Smad2 and STAT3 for colorectal cancer therapy.

  6. Intestinal stem cell overproliferation resulting from inactivation of the APC tumor suppressor requires the transcription cofactors Earthbound and Erect wing.

    Science.gov (United States)

    Tian, Ai; Benchabane, Hassina; Wang, Zhenghan; Zimmerman, Chloe; Xin, Nan; Perochon, Jessica; Kalna, Gabriela; Sansom, Owen J; Cheng, Chao; Cordero, Julia B; Ahmed, Yashi

    2017-07-01

    Wnt/β-catenin signal transduction directs intestinal stem cell (ISC) proliferation during homeostasis. Hyperactivation of Wnt signaling initiates colorectal cancer, which most frequently results from truncation of the tumor suppressor Adenomatous polyposis coli (APC). The β-catenin-TCF transcription complex activates both the physiological expression of Wnt target genes in the normal intestinal epithelium and their aberrantly increased expression in colorectal tumors. Whether mechanistic differences in the Wnt transcription machinery drive these distinct levels of target gene activation in physiological versus pathological states remains uncertain, but is relevant for the design of new therapeutic strategies. Here, using a Drosophila model, we demonstrate that two evolutionarily conserved transcription cofactors, Earthbound (Ebd) and Erect wing (Ewg), are essential for all major consequences of Apc1 inactivation in the intestine: the hyperactivation of Wnt target gene expression, excess number of ISCs, and hyperplasia of the epithelium. In contrast, only Ebd, but not Ewg, mediates the Wnt-dependent regulation of ISC proliferation during homeostasis. Therefore, in the adult intestine, Ebd acts independently of Ewg in physiological Wnt signaling, but cooperates with Ewg to induce the hyperactivation of Wnt target gene expression following Apc1 loss. These findings have relevance for human tumorigenesis, as Jerky (JRK/JH8), the human Ebd homolog, promotes Wnt pathway hyperactivation and is overexpressed in colorectal, breast, and ovarian cancers. Together, our findings reveal distinct requirements for Ebd and Ewg in physiological Wnt pathway activation versus oncogenic Wnt pathway hyperactivation following Apc1 loss. Such differentially utilized transcription cofactors may offer new opportunities for the selective targeting of Wnt-driven cancers.

  7. Peroxisome proliferator-activated receptor gamma coactivator-1 alpha acts as a tumor suppressor in hepatocellular carcinoma.

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    Liu, Rui; Zhang, Haiyang; Zhang, Yan; Li, Shuang; Wang, Xinyi; Wang, Xia; Wang, Cheng; Liu, Bin; Zen, Ke; Zhang, Chen-Yu; Zhang, Chunni; Ba, Yi

    2017-04-01

    Peroxisome proliferator-activated receptor gamma coactivator-1 alpha plays a crucial role in regulating the biosynthesis of mitochondria, which is closely linked to the energy metabolism in various tumors. This study investigated the regulatory role of peroxisome proliferator-activated receptor gamma coactivator-1 alpha in the pathogenesis of hepatocellular carcinoma. In this study, the changes of peroxisome proliferator-activated receptor gamma coactivator-1 alpha messenger RNA levels between normal human liver and hepatocellular carcinoma tissue were examined by quantitative reverse transcription polymerase chain reaction. Knockdown of peroxisome proliferator-activated receptor gamma coactivator-1 alpha was conducted by RNA interference in the human liver cell line L02, while overexpression of peroxisome proliferator-activated receptor gamma coactivator-1 alpha was conducted by adenovirus encoding peroxisome proliferator-activated receptor gamma coactivator-1 alpha complementary DNA in the human hepatocarcinoma cell line HepG2. Cellular morphological changes were observed via optical and electron microscopy. Cellular apoptosis was determined by Hoechst 33258 staining. In addition, the expression levels of 21,400 genes in tissues and cells were detected by microarray. It was shown that peroxisome proliferator-activated receptor gamma coactivator-1 alpha expression was significantly downregulated in hepatocellular carcinoma compared with normal liver tissues. After knockdown of peroxisome proliferator-activated receptor gamma coactivator-1 alpha expression in L02 cells, cells reverted to immature and dedifferentiated morphology exhibiting cancerous tendency. Apoptosis occurred in the HepG2 cells after transfection by adenovirus encoding peroxisome proliferator-activated receptor gamma coactivator-1 alpha. Microarray analysis showed consistent results. The results suggest that peroxisome proliferator-activated receptor gamma coactivator-1 alpha acts as a tumor

  8. Amino-terminal enhancer of split gene AES encodes a tumor and metastasis suppressor of prostate cancer.

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    Okada, Yoshiyuki; Sonoshita, Masahiro; Kakizaki, Fumihiko; Aoyama, Naoki; Itatani, Yoshiro; Uegaki, Masayuki; Sakamoto, Hiromasa; Kobayashi, Takashi; Inoue, Takahiro; Kamba, Tomomi; Suzuki, Akira; Ogawa, Osamu; Taketo, M Mark

    2017-04-01

    A major cause of cancer death is its metastasis to the vital organs. Few effective therapies are available for metastatic castration-resistant prostate cancer (PCa), and progressive metastatic lesions such as lymph nodes and bones cause mortality. We recently identified AES as a metastasis suppressor for colon cancer. Here, we have studied the roles of AES in PCa progression. We analyzed the relationship between AES expression and PCa stages of progression by immunohistochemistry of human needle biopsy samples. We then performed overexpression and knockdown of AES in human PCa cell lines LNCaP, DU145 and PC3, and determined the effects on proliferation, invasion and metastasis in culture and in a xenograft model. We also compared the PCa phenotypes of Aes/Pten compound knockout mice with those of Pten simple knockout mice. Expression levels of AES were inversely correlated with clinical stages of human PCa. Exogenous expression of AES suppressed the growth of LNCaP cells, whereas the AES knockdown promoted it. We also found that AES suppressed transcriptional activities of androgen receptor and Notch signaling. Notably, AES overexpression in AR-defective DU145 and PC3 cells reduced invasion and metastasis to lymph nodes and bones without affecting proliferation in culture. Consistently, prostate epithelium-specific inactivation of Aes in Ptenflox/flox mice increased expression of Snail and MMP9, and accelerated growth, invasion and lymph node metastasis of the mouse prostate tumor. These results suggest that AES plays an important role in controlling tumor growth and metastasis of PCa by regulating both AR and Notch signaling pathways. © 2017 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

  9. Differential Splicing of Oncogenes and Tumor Suppressor Genes in African- and Caucasian-American Populations: Contributing Factor in Prostate Cancer Disparities

    Science.gov (United States)

    2015-10-01

    Lee, N. H. Molecular cloning, tissue-specific expression, and chromosomal localization of a novel nerve growth factor- regulated G-protein- coupled...American, oncogenes, tumor suppressor genes, phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit delta, fibroblast growth factor receptor 3... regulate RNA splicing, microRNA and transcription are associated with prostate cancer survival. Clinical Cancer Res. (submitted) iv. Manuscript in

  10. A fine balance: epigenetic control of cellular quiescence by the tumor suppressor PRDM2/RIZ at a bivalent domain in the cyclin a gene

    OpenAIRE

    Cheedipudi, Sirisha; Puri, Deepika; Saleh, Amena; Gala, Hardik P.; Rumman, Mohammed; Pillai, Malini S.; Sreenivas, Prethish; Arora, Reety; Sellathurai, Jeeva; Schr?der, Henrik Daa; Mishra, Rakesh K.; Dhawan, Jyotsna

    2015-01-01

    Adult stem cell quiescence is critical to ensure regeneration while minimizing tumorigenesis. Epigenetic regulation contributes to cell cycle control and differentiation, but few regulators of the chromatin state in quiescent cells are known. Here we report that the tumor suppressor PRDM2/RIZ, an H3K9 methyltransferase, is enriched in quiescent muscle stem cells in vivo and controls reversible quiescence in cultured myoblasts. We find that PRDM2 associates with >4400 promoters in G0 myobla...

  11. Differential Splicing of Oncogenes and Tumor Suppressor Genes in African- and Caucasian-American Populations: Contributing Factor in Prostate Cancer Disparities

    Science.gov (United States)

    2016-10-01

    American, oncogenes, tumor suppressor genes 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 19a. NAME OF RESPONSIBLE...therapy, which is particularly germane in hematologic malignancies. Idelalisib is FDA approved for relapsed chronic lymphocytic leukemia and relapsed...leukocytes 73,74. Previous studies have revealed a crucial role of PI3Kδ in development and progression of lymphoid and myeloid malignancies 34,75

  12. From oncogene to tumor suppressor: the dual role of Myc in leukemia.

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    Uribesalgo, Iris; Benitah, Salvador Aznar; Di Croce, Luciano

    2012-05-01

    The transcription factor c-Myc strongly stimulates cell proliferation but also regulates apoptosis, senescence, cell competition and cell differentiation, and its elevated activity is a hallmark for human tumorigenesis. c-Myc induces transcription by forming heterodimers with Max and then directly binding DNA at E-box sequences. Conversely, transcription repression depends primarily on the inhibitory interaction of c-Myc/Max with Miz-1 at DNA initiator elements. We recently described a distinct mechanism of c-Myc gene regulation, in which c-Myc interacts with the retinoic acid receptor α (RARα) and is recruited to RAR DNA binding sequences (RAREs). In leukemia cells, this c-Myc/RARα complex functions either as an activator or a repressor of RARα-dependent targets through a phosphorylation switch. Unphosphorylated c-Myc interacts with RARα to repress the expression of RAR targets required for differentiation, thereby aggravating leukemia malignancy. However, if c-Myc is phosphorylated by the kinase Pak2, the c-Myc/RARα complex activates transcription of those same genes to stimulate differentiation, thus reducing tumor burden. Here, we discuss the role of c-Myc in balancing proliferation and differentiation and how modulating this previously unidentified c-Myc activity might provide alternative therapies against leukemia and possibly other types of tumors.

  13. Extensive analysis of D7S486 in primary gastric cancer supports TESTIN as a candidate tumor suppressor gene

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    Zhou Zhiwei

    2010-07-01

    Full Text Available Abstract Background High frequency of loss of heterozygosity (LOH was found at D7S486 in primary gastric cancer (GC. And we found a high frequency of LOH region on 7q31 in primary GC from China, and identified D7S486 to be the most frequent LOH locus. This study was aimed to determine what genes were affected by the LOH and served as tumor suppressor genes (TSGs in this region. Here, a high-throughput single nucleotide polymorphisms (SNPs microarray fabricated in-house was used to analyze the LOH status around D7S486 on 7q31 in 75 patients with primary GC. Western blot, immunohistochemistry, and RT-PCR were used to assess the protein and mRNA expression of TESTIN (TES in 50 and 140 primary GC samples, respectively. MTS assay was used to investigate the effect of TES overexpression on the proliferation of GC cell lines. Mutation and methylation analysis were performed to explore possible mechanisms of TES inactivation in GC. Results LOH analysis discovered five candidate genes (ST7, FOXP2, MDFIC, TES and CAV1 whose frequencies of LOH were higher than 30%. However, only TES showed the potential to be a TSG associated with GC. Among 140 pairs of GC samples, decreased TES mRNA level was found in 96 (68.6% tumor tissues when compared with matched non-tumor tissues (p p = 0.001. In addition, immunohistochemical staining result was in agreement with that of RT-PCR and Western blot. Down regulation of TES was shown to be correlated with tumor differentiation (p = 0.035 and prognosis (p = 0.035, log-rank test. Its overexpression inhibited the growth of three GC cell lines. Hypermethylation of TES promoter was a frequent event in primary GC and GC cell lines. However, no specific gene mutation was observed in the coding region of the TES gene. Conclusions Collectively, all results support the role of TES as a TSG in gastric carcinogenesis and that TES is inactivated primarily by LOH and CpG island methylation.

  14. 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.

  15. Ibrutinib downregulates a subset of miRNA leading to upregulation of tumor suppressors and inhibition of cell proliferation in chronic lymphocytic leukemia.

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    Saleh, L M; Wang, W; Herman, S E M; Saba, N S; Anastas, V; Barber, E; Corrigan-Cummins, M; Farooqui, M; Sun, C; Sarasua, S M; Zhao, Z; Abousamra, N K; Elbaz, O; Abdelghaffar, H A; Wiestner, A; Calvo, K R

    2017-02-01

    The lymph node (LN) is the site of chronic lymphocytic leukemia (CLL) cell activation and proliferation. Aberrant microRNA (miRNA) expression has been shown to have a role in CLL pathogenesis; however, a comparison of miRNA expression between CLL cells in the LN and the peripheral blood (PB) has previously not been reported. On the basis of the analysis of 17 paired LN and PB samples from CLL patients, we identify a panel of miRNAs that are increased in LN CLL cells correlating with an activation phenotype. When evaluated in CLL cells from 38 patients pre and post treatment with ibrutinib, a subset of these miRNAs (miR-22, miR-34a, miR-146b and miR-181b) was significantly decreased in response to ibrutinib. A concomitant increase in putative miRNA target transcripts (ARID1B, ARID2, ATM, CYLD, FOXP1, HDAC1, IBTK, PTEN and SMAD4) was also observed. Functional studies confirmed targets of ibrutinib-responsive miRNAs to include messenger RNA transcripts of multiple tumor suppressors. Knockdown of endogenous miR-34a and miR146b resulted in increased transcription of tumor suppressors and inhibition of cell proliferation. These findings demonstrate that ibrutinib downregulates the expression of a subset of miRNAs related to B-cell activation leading to increased expression of miRNA targets including tumor suppressors and a reduction in cell proliferation.

  16. MicroRNA-135b Regulates Leucine Zipper Tumor Suppressor 1 in Cutaneous Squamous Cell Carcinoma.

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    Edit B Olasz

    Full Text Available Cutaneous squamous cell carcinoma (cSCC is the second most common skin malignancy and it presents a therapeutic challenge in organ transplant recipient patients. Despite the need, there are only a few targeted drug treatment options. Recent studies have revealed a pivotal role played by microRNAs (miRNAs in multiple cancers, but only a few studies tested their function in cSCC. Here, we analyzed differential expression of 88 cancer related miRNAs in 43 study participants with cSCC; 32 immunocompetent, 11 OTR patients, and 15 non-lesional skin samples by microarray analysis. Of the examined miRNAs, miR-135b was the most upregulated (13.3-fold, 21.5-fold; p=0.0001 in both patient groups. Similarly, the miR-135b expression was also upregulated in three cSCC cell lines when evaluated by quantitative real-time PCR. In functional studies, inhibition of miR-135b by specific anti-miR oligonucleotides resulted in upregulation of its target gene LZTS1 mRNA and protein levels and led to decreased cell motility and invasion of both primary and metastatic cSCC cell lines. In contrast, miR-135b overexpression by synthetic miR-135b mimic induced further down-regulation of LZTS1 mRNA in vitro and increased cancer cell motility and invasiveness. Immunohistochemical evaluation of 67 cSCC tumor tissues demonstrated that miR-135b expression inversely correlated with LZTS1 staining intensity and the tumor grade. These results indicate that miR-135b functions as an oncogene in cSCC and provide new understanding into its pathological role in cSCC progression and invasiveness.

  17. Novel Role of Merlin Tumor Suppressor in Autophagy and Its Implication in Treating NF2-Associated Tumors

    Science.gov (United States)

    2015-06-01

    Although tumors in NF2 patients are mostly benign, they ultimately compress neighboring nerves or  increase  intracranial   pressure , and cause a range of...knock‐down was associated with enhanced cellular stress that would promote tumorigenesis.    These  analyses  provide new insight into the role of Merlin...results of LC3 coupling efficiency, as well as autophagy induction  analyses  (Figures 7‐9), suggest that  the role of Merlin in autophagy has general

  18. The parafibromin tumor suppressor protein interacts with actin-binding proteins actinin-2 and actinin-3

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    Marx Stephen J

    2008-08-01

    Full Text Available Abstract Background Germline and somatic inactivating mutations in the HRPT2 gene occur in the inherited hyperparathyroidism-jaw tumor syndrome, in some cases of parathyroid cancer and in some cases of familial hyperparathyroidism. HRPT2 encodes parafibromin. To identify parafibromin interacting proteins we used the yeast two-hybrid system for screening a heart cDNA library with parafibromin as the bait. Results Fourteen parafibromin interaction positive preys representing 10 independent clones encoding actinin-2 were isolated. Parafibromin interacted with muscle alpha-actinins (actinin-2 and actinin-3, but not with non-muscle alpha-actinins (actinin-1 and actinin-4. The parafibromin-actinin interaction was verified by yeast two-hybrid, GST pull-down, and co-immunoprecipitation. Yeast two-hybrid analysis revealed that the N-terminal region of parafibromin interacted with actinins. In actin sedimentation assays parafibromin did not dissociate skeletal muscle actinins from actin filaments, but interestingly, parafibromin could also bundle/cross-link actin filaments. Parafibromin was predominantly nuclear in undifferentiated proliferating myoblasts (C2C12 cells, but in differentiated C2C12 myotubes parafibromin co-localized with actinins in the cytoplasmic compartment. Conclusion These data support a possible contribution of parafibromin outside the nucleus through its interaction with actinins and actin bundling/cross-linking. These data also suggest that actinins (and actin participate in sequestering parafibromin in the cytoplasmic compartment.

  19. MiR-145 functions as a tumor suppressor targeting NUAK1 in human intrahepatic cholangiocarcinoma

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    Xiong, Xinkui; Sun, Daoyi; Chai, Hao; Shan, Wengang [Liver Transplantation Center, First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province (China); Key Laboratory of Living Donor Liver Transplantation, Ministry of Public Health, Nanjing, Jiangsu Province (China); Yu, Yue [Key Laboratory of Living Donor Liver Transplantation, Ministry of Public Health, Nanjing, Jiangsu Province (China); Pu, Liyong [Liver Transplantation Center, First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province (China); Key Laboratory of Living Donor Liver Transplantation, Ministry of Public Health, Nanjing, Jiangsu Province (China); Cheng, Feng, E-mail: docchengfeng@njmu.edu.cn [Liver Transplantation Center, First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province (China); Key Laboratory of Living Donor Liver Transplantation, Ministry of Public Health, Nanjing, Jiangsu Province (China)

    2015-09-18

    The dysregulation of micro (mi)RNAs is associated with cancer development. The miRNA miR-145 is downregulated in intrahepatic cholangiocarcinoma (ICC); however, its precise role in tumor progression has not yet been elucidated. Novel (nua) kinase family (NUAK)1 functions as an oncogene in various cancers and is a putative target of miR-145 regulation. In this study, we investigated the regulation of NUAK1 by miR-145 in ICC. We found that miR-145 level was significantly decreased in ICC tissue and cell lines, which corresponded with an increase in NUAK1 expression. NUAK1 was found to be a direct target of miR-145 regulation. The overexpression of miR-145 in ICC cell lines inhibited proliferation, growth, and invasion by suppressing NUAK1 expression, which was associated with a decrease in Akt signaling and matrix metalloproteinase protein expression. Similar results were observed by inhibiting NUAK1 expression. These results demonstrate that miR-145 can prevent ICC progression by targeting NUAK1 and its downstream effectors, and can therefore be useful for clinical diagnosis and targeted therapy of ICC. - Highlights: • MiR-145 suppresses ICC proliferation and invasion abilities. • We demonstrated that miR-145 directly targets NUAK1 in ICC. • MiR-145 expression in ICC was associated with Akt signaling and MMPs expression.

  20. Loss of Mitochondrial Tumor Suppressor Genes Expression Is Associated with Unfavorable Clinical Outcome in Head and Neck Squamous Cell Carcinoma: Data from Retrospective Study.

    Directory of Open Access Journals (Sweden)

    Ishrat Mahjabeen

    Full Text Available Mitochondrial genes play important roles in cellular energy metabolism, free radical generation, and apoptosis. Dysregulation of these genes have long been suspected to contribute to the generation of reactive oxygen species (ROS, increased proliferation and progression of cancer. A family of orthologues of yeast silent information regulator 3 (SIRT3, 4 (SIRT4 and mitochondrial tumor suppressor 1 (MTUS1 are important mitochondrial tumor suppressor genes which play an important role in the progression of multiple cancers. However, their role in the development of oxidative stress, enhanced proliferation and progression of head and neck squamous cell carcinoma (HNSCC has not yet been studied. In this study we aimed to test the association between reduced mitochondrial tumor suppressor genes' activities and enhancement in tissue oxidative stress and cell proliferation in HNSCC cases. The expression of mitochondrial tumor suppressor genes (SIRT3, SIRT4 and MTUS1, mitochondrial DNA repair gene (OGG1-2a and a proliferation marker (Ki-67 was studied in a study cohort of 120 HNSCC patients and controls with reverse transcriptase polymerase chain reaction (RT-PCR and real-time PCR (qPCR in order to determine the potential prognostic significance of these genes. A statistically significant downregulation of SIRT3 (p<0.001, SIRT4 (p<0.0001, MTUS1 (p<0.002 and OGG1 (p<0.0001 was observed in HNSCC compared to control samples. Ki-67 was also overexpressed (p<0.0001 in HNSCC versus control samples. Additionally, to explore gene-gene relationship, we observed a positive spearmen correlation between SIRT3 versus SIRT4 (r = 0.523***, p<0.0001, SIRT3 versus MTUS1 (r = 0.273***, p<0.001, SIRT3 versus OGG1-2a (r = 0.213*, p<0.03, SIRT4 versus OGG1 (r = 0.338***, p<0.0001 and MTUS1 versus OGG1-2a (r = 0.215*, p<0.03 in HNSCC cases. A negative spearman correlation was observed between OGG1 versus Ki-67 (r = -0.224**, p<0.01 and OGG1-2a versus Ki-67 (r = -0.224**, p<0

  1. Tumor Suppressor A20 Protects against Cardiac Hypertrophy and Fibrosis through Blocking TAK1-Dependent Signaling

    Science.gov (United States)

    Huang, He; Tang, Qi-Zhu; Wang, Ai-Bing; Chen, Manyin; Zhou, Heng; Liu, Chen; Jiang, Hong; Yang, Qinglin; Bian, Zhou-Yan; Bai, Xue; Zhu, Li-Hua; Wang, Lang; Li, Hongliang

    2010-01-01

    A20 or tumor necrosis factor–induced protein 3 is a negative regulator of nuclear factor κB signaling. A20 has been shown previously to attenuate cardiac hypertrophy in vitro and postmyocardial infarction remodeling in vivo. In the present study, we tested the hypothesis that overexpression of A20 in the murine heart would protect against cardiac hypertrophy in vivo. The effects of constitutive human A20 expression on cardiac hypertrophy were investigated using in vitro and in vivo models. Cardiac hypertrophy was produced by aortic banding in A20 transgenic mice and control animals. The extent of cardiac hypertrophy was quantitated by echocardiography, as well as by pathological and molecular analyses of heart samples. Constitutive overexpression of human A20 in the murine heart attenuated the hypertrophicresponse and markedly reduced inflammation, apoptosis, and fibrosis. Cardiac function was also preserved in hearts with increased A20 levels in response to hypertrophic stimuli. Western blot experiments further showed A20 expression markedly blocked transforming growth factor-β–activated kinase 1–dependent c-Jun N-terminal kinase/p38 signaling cascade but with no difference in either extracellular signal-regulated kinase 1/2 or AKT activation in vivo and in vitro. In cultured neonatal rat cardiac myocytes, [3H]proline incorporation and Western blot assays revealed that A20 expression suppressed transforming growth factor-β–induced collagen synthesis and transforming growth factor-β–activated kinase 1–dependent Smad 2/3/4 activation. In conclusion, A20 improves cardiac functions and inhibits cardiac hypertrophy, inflammation, apoptosis, and fibrosis by blocking transforming growth factor-β–activated kinase 1–dependent signaling. PMID:20585109

  2. Truncation of the Catalytic Domain of the Cylindromatosis Tumor Suppressor Impairs Lung Maturation

    Directory of Open Access Journals (Sweden)

    Eirini Trompouki

    2009-05-01

    Full Text Available Cyld encodes a 956-amino acid deubiquitinating enzyme (CYLD, which is a negative regulator of nuclear factor κB and mitogen-activated protein kinase pathways. Mutations that truncate and inactivate the carboxyl-terminal deubiquitinating domain of CYLD underlie the development of skin appendage tumors in humans, whereas down-regulation of Cyld expression has been associated with the development of various types of human malignancies including lung cancer. To establish an animal model of human CYLD inactivation and characterize the biological role of CYLD in vivo, we generated mice carrying a homozygous deletion of Cyld exon 9 (CyldΔ9/Δ9 mice using a conditional approach. Deletion of exon 9 would cause a carboxyl-terminal truncation of CYLD and inactivation of its deubiquitinating activity. In accordance with previous studies, fibroblasts from CyldΔ9/Δ9 embryos had hyperactive nuclear factor κB and c-Jun kinase pathways compared with control fibroblasts. CyldΔ9/Δ9 newborn mice were smaller than wild-type littermates with a short and kinky tail and nomajor developmental defects. However, CyldΔ9/Δ9 mice died shortly after birth from apparent respiratory dysfunction. Histological examination of E18.5 CyldΔ9/Δ9 lungs demonstrated an immature phenotype characterized by hyperplasic mesenchyme but apparently normal epithelial, smooth muscle. and endothelial structures. Our study identifies an important role of CYLD in lung maturation, which may underlie the development of many cases of lung cancer.

  3. A novel Golgi retention signal RPWS for tumor suppressor UBIAD1.

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    Xian Wang

    Full Text Available UBIAD1 plays critical roles in physiology including vitamin K and CoQ10 biosynthesis as well as pathophysiology including dyslipimedia-induced SCD (Schnyder's corneal dystrophy, Parkinson's disease, cardiovascular disease and bladder carcinoma. Since the subcellular localization of UBIAD1 varies in different cell types, characterization of the exact subcellular localization of UBIAD1 in specific human disease is vital for understanding its molecular mechanism. As UBIAD1 suppresses bladder carcinoma, we studied its subcellular localization in human bladder carcinoma cell line T24. Since fluorescent images of UBIAD1-EGFP in T24, human prostate cancer cell line PC-3, human embryonic kidney cell line HEK293 and human hepatocyte cell line L02 are similar, these four cell lines were used for present study. Using a combination of fluorescent microscopy and immunohistochemistry, it was found that UBIAD1 localized on the Golgi and endoplasmic reticulum (ER, but not on the plasma membrane, of T24 and HEK293 cells. Using scanning electron microscopy and western blot analysis, we found that UBIAD1 is enriched in the Golgi fraction extracted from the L02 cells, verifying the Golgi localization of UBAID1. Site-directed mutagenesis showed that the RPWS motif, which forms an Arginine finger on the UBIAD1 N terminus, serves as the Golgi retention signal. With both cycloheximide and brefeldin A inhibition assays, it was shown that UBIAD1 may be transported from the endoplasmic reticulum (ER to the Golgi by a COPII-mediated mechanism. Based upon flow cytometry analysis, it is shown that mutation of the RPWS motif reduced the UBIAD1-induced apoptosis of T24 cells, indicating that the proper Golgi localization of UBIAD1 influences its tumor suppressant activity. This study paves the way for further understanding the molecular mechanism of UBIAD1 in human diseases.

  4. Human gamma interferon and tumor necrosis factor exert a synergistic blockade on the replication of herpes simplex virus.

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    Feduchi, E; Alonso, M A; Carrasco, L

    1989-03-01

    The replication of herpes simplex virus type 1 (HSV-1) is not inhibited in either HeLa or HEp-2 cells treated with human alpha interferon (HuIFN-alpha), particularly when high multiplicities of infection are used. However, HuIFN-gamma partially inhibits HSV-1 translation in HEp-2 cells infected at low multiplicities. Under these conditions, the transcription of genes alpha 22, TK, and gamma 0 is greatly diminished. The combined addition of human tumor necrosis factor (TNF) and HuIFN-gamma to HEp-2 cells exerts a synergistic inhibition of HSV-1 translation. Cells treated with both cytokines continue synthesizing cellular proteins, even 20 h after HSV-1 infection. As little as 10 U of IFN-gamma per ml blocked HSV-1 DNA replication, provided that TNF was also present in the medium. Analyses of HSV-1 gene transcription suggest that the action of both TNF and IFN-gamma blocked a step that comes at or prior to early HSV-1 gene expression. This early step in HSV-1 replication inhibited by TNF and IFN-gamma occurs after virus attachment and entry into cells, since the internalization of radioactive HSV-1 virion particles was not blocked by the presence of the two cytokines. Therefore, we conclude that the synergistic action of TNF plus IFN-gamma affects a step in HSV-1 replication that comes after virus entry but before or at the transcription of immediate-early genes.

  5. An innovative immunosensor for detection of tumor suppressor protein p53 in unprocessed human plasma and cancer cell lysates.

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    Hasanzadeh, Mohammad; Baghban, Hossein Navay; Mokhtarzadeh, Ahad; Shadjou, Nasrin; Mahboob, Soltanali

    2017-12-01

    An innovative mediator-free electrochemical immunosensor for quantitation of p53 tumor suppressor protein based on signal amplification strategy was fabricated. In this work, biotin conjugated p53-antibody (anti-p53) was immobilized onto a green and biocompatible nanocomposite containing poly l-cysteine (P-Cys) as conductive matrix and 3D gold nanoparticles (GNPs) as signal amplification element. Therefore, a novel nanocomposite film based on P-Cys and GNPs was exploited to develop a highly sensitive immunosensor for detection of p53 protein. Importantly, GNPs prepared by sonoelectrodeposition method which lead to compact morphology. Fully electrochemical methodology was used to prepare a new transducer on a gold surface which provided a high surface area to immobilize a high amount of the anti-p53. The surface morphology of electrode was characterized by high-resolution field emission scanning electron microscope (FE-SEM) and energy dispersive spectroscopy (EDX). The immunosensor was employed for the detection of p53 in physiological pH using square wav voltammetry and differential pulse voltammetry (DPVs) techniques. Under optimized condition the calibration curve for p53 concentration by SWV and DPV was linear in 0.0369-50pM and 0.018-2.5pM with lower limit of quantification of 48fM and 18fM, respectively. The method was successfully applied assay of the p53 in unprocessed human plasma samples. Also, the method was applied to the assay of p53 in human plasma sample and normal and malignant cell line lysates such as (L929 normal cell Line from mouse C3H (L929), colon cancer cell-HCT, prostate cancer cell line PC-3, and human breast adenocarcinoma cell line-MCF7). Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Tumor Suppressor Interferon-Regulatory Factor 1 Counteracts the Germinal Center Reaction Driven by a Cancer-Associated Gammaherpesvirus.

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    Mboko, Wadzanai P; Olteanu, Horatiu; Ray, Avijit; Xin, Gang; Darrah, Eric J; Kumar, Suresh N; Kulinski, Joseph M; Cui, Weiguo; Dittel, Bonnie N; Gauld, Stephen B; Tarakanova, Vera L

    2015-12-30

    Gammaherpesviruses are ubiquitous pathogens that are associated with the development of B cell lymphomas. Gammaherpesviruses employ multiple mechanisms to transiently stimulate a broad, polyclonal germinal center reaction, an inherently mutagenic stage of B cell differentiation that is thought to be the primary target of malignant transformation in virus-driven lymphomagenesis. We found that this gammaherpesvirus-driven germinal center expansion was exaggerated and lost its transient nature in the absence of interferon-regulatory factor 1 (IRF-1), a transcription factor with antiviral and tumor suppressor functions. Uncontrolled and persistent expansion of germinal center B cells led to pathological changes in the spleens of chronically infected IRF-1-deficient animals. Additionally, we found decreased IRF-1 expression in cases of human posttransplant lymphoproliferative disorder, a malignant condition associated with gammaherpesvirus infection. The results of our study define an unappreciated role for IRF-1 in B cell biology and provide insight into the potential mechanism of gammaherpesvirus-driven lymphomagenesis. Gammaherpesviruses establish lifelong infection in most adults and are associated with B cell lymphomas. While the infection is asymptomatic in many hosts, it is critical to identify individuals who may be at an increased risk of virus-induced cancer. Such identification is currently impossible, as the host risk factors that predispose individuals toward viral lymphomagenesis are poorly understood. The current study identifies interferon-regulatory factor 1 (IRF-1) to be one of such candidate host factors. Specifically, we found that IRF-1 enforces long-term suppression of an inherently mutagenic stage of B cell differentiation that gammaherpesviruses are thought to target for transformation. Correspondingly, in the absence of IRF-1, chronic gammaherpesvirus infection induced pathological changes in the spleens of infected animals. Further, we found

  7. miR-132 and miR-212 are increased in pancreatic cancer and target the retinoblastoma tumor suppressor.

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    Park, Jong-Kook; Henry, Jon C; Jiang, Jinmai; Esau, Christine; Gusev, Yuriy; Lerner, Megan R; Postier, Russell G; Brackett, Daniel J; Schmittgen, Thomas D

    2011-03-25

    Numerous microRNAs (miRNAs) are reported as differentially expressed in cancer, however the consequence of miRNA deregulation in cancer is unknown for many miRNAs. We report that two miRNAs located on chromosome 17p13, miR-132 and miR-212, are over-expressed in pancreatic adenocarcinoma (PDAC) tissues. Both miRNAs are predicted to target the retinoblastoma tumor suppressor, Rb1. Validation of this interaction was confirmed by luciferase reporter assay and western blot in a pancreatic cancer cell line transfected with pre-miR-212 and pre-miR-132 oligos. Cell proliferation was enhanced in Panc-1 cells transfected with pre-miR-132/-212 oligos. Conversely, antisense oligos to miR-132/-212 reduced cell proliferation and caused a G(2)/M cell cycle arrest. The mRNA of a number of E2F transcriptional targets were increased in cells over expressing miR-132/-212. Exposing Panc-1 cells to the β2 adrenergic receptor agonist, terbutaline, increased the miR-132 and miR-212 expression by 2- to 4-fold. We report that over-expression of miR-132 and miR-212 result in reduced pRb protein in pancreatic cancer cells and that the increase in cell proliferation from over-expression of these miRNAs is likely due to increased expression of several E2F target genes. The β2 adrenergic pathway may play an important role in this novel mechanism. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. CDKN1C/p57kip2 is a candidate tumor suppressor gene in human breast cancer

    Directory of Open Access Journals (Sweden)

    Pistey Robert

    2008-03-01

    Full Text Available Abstract Background CDKN1C (also known as p57KIP2 is a cyclin-dependent kinase inhibitor previously implicated in several types of human cancer. Its family members (CDKN1A/p21CIP1 and B/p27KIP1 have been implicated in breast cancer, but information about CDKN1C's role is limited. We hypothesized that decreased CDKN1C may be involved in human breast carcinogenesis in vivo. Methods We determined rates of allele imbalance or loss of heterozygosity (AI/LOH in CDKN1C, using an intronic polymorphism, and in the surrounding 11p15.5 region in 82 breast cancers. We examined the CDKN1C mRNA level in 10 cancers using quantitative real-time PCR (qPCR, and the CDKN1C protein level in 20 cancers using immunohistochemistry (IHC. All samples were obtained using laser microdissection. Data were analyzed using standard statistical tests. Results AI/LOH at 11p15.5 occurred in 28/73 (38% informative cancers, but CDKN1C itself underwent AI/LOH in only 3/16 (19% cancers (p = ns. In contrast, CDKN1C mRNA levels were reduced in 9/10 (90% cancers (p Conclusion CDKN1C is expressed in normal epithelium of most breast cancer cases, mainly in the myothepithelial layer. This expression decreases, at both the mRNA and protein level, in the large majority of breast cancers, and does not appear to be mediated by AI/LOH at the gene. Thus, CDKN1C may be a breast cancer tumor suppressor.

  9. High frequency electromagnetic fields (GSM signals) affect gene expression levels in tumor suppressor p53-deficient embryonic stem cells.

    Science.gov (United States)

    Czyz, Jaroslaw; Guan, Kaomei; Zeng, Qinghua; Nikolova, Teodora; Meister, Armin; Schönborn, Frank; Schuderer, Jürgen; Kuster, Niels; Wobus, Anna M

    2004-05-01

    Effects of electromagnetic fields (EMF) simulating exposure to the Global System for Mobile Communications (GSM) signals were studied using pluripotent embryonic stem (ES) cells in vitro. Wild-type ES cells and ES cells deficient for the tumor suppressor p53 were exposed to pulse modulated EMF at 1.71 GHz, lower end of the uplink band of GSM 1800, under standardized and controlled conditions, and transcripts of regulatory genes were analyzed during in vitro differentiation. Two dominant GSM modulation schemes (GSM-217 and GSM-Talk), which generate temporal changes between GSM-Basic (active during talking phases) and GSM-DTX (active during listening phases thus simulating a typical conversation), were applied to the cells at and below the basic safety limits for local exposures as defined for the general public by the International Commission on Nonionizing Radiation Protection (ICNIRP). GSM-217 EMF induced a significant upregulation of mRNA levels of the heat shock protein, hsp70 of p53-deficient ES cells differentiating in vitro, paralleled by a low and transient increase of c-jun, c-myc, and p21 levels in p53-deficient, but not in wild-type cells. No responses were observed in either cell type after EMF exposure to GSM-Talk applied at similar slot-averaged specific absorption rates (SAR), but at lower time-averaged SAR values. Cardiac differentiation and cell cycle characteristics were not affected in embryonic stem and embryonic carcinoma cells after exposure to GSM-217 EMF signals. Our data indicate that the genetic background determines cellular responses to GSM modulated EMF. Bioelectromagnetics 25:296-307, 2004. Copyright 2004 Wiley-Liss, Inc.

  10. MicroRNA-30e Functions as a Tumor Suppressor in Cervical Carcinoma Cells through Targeting GALNT7

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    Huijuan Wu

    2017-12-01

    Full Text Available Cervical cancer is the third most common cancer in women worldwide. However, the underlying mechanism of occurrence and development of cervical cancer is obscure. In this study, we observed that miR-30e was downregulated in clinical cervical cancer tissues and cervical cancer cells. Next, overexpression of miR-30e reduced the cervical cancer cell growth through MTT, colony formation, EdU, and Transwell assay in SiHa and Caski cells. Subsequently, UDP-N-acetyl-D-galactosamine: polypeptide N-acetylgalactosaminyltransferase 7 (GALNT7 was identified as a potential miR-30e target by bioinformatics analysis. Moreover, we showed that miR-30e was able to bind to the 3′UTR of GALNT7 by luciferase reporter assay. In addition, the mRNA and protein levels of GALNT7 in cervical cancer cells were downregulated by miR-30e. And we validated that downregulation of GALNT7 repressed the proliferation of SiHa and Caski cells by MTT, colony formation, and Transwell assay. We identified that the restoration of GALNT7 expression was able to counteract the effect of miR-30e on cell proliferation of cervical cancer cells. Furthermore, we found that the expression levels of GALNT7 were frequently upregulated and negatively correlative to those of miR-30e in cervical cancer tissues. In addition, we validated that restoration of GALNT7 rescued the miR-30e–suppressed growth of cervical cancer xenografts in vivo. In conclusion, the current results suggest that miR-30e may function as tumor suppressors in cervical cancer through downregulation of GALNT7. Both miR-30e and its novel target, GALNT7, may play an important role in the process of cervical cancer.

  11. MTHFR variants reduce the risk of G:C->A:T transition mutations within the p53 tumor suppressor gene in colon tumors.

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    Ulrich, C M; Curtin, K; Samowitz, W; Bigler, J; Potter, J D; Caan, B; Slattery, M L

    2005-10-01

    5,10-Methylene-tetrahydrofolate reductase (MTHFR) is a key enzyme in folate-mediated 1-carbon metabolism. Reduced MTHFR activity has been associated with genomic DNA hypomethylation. Methylated cytosines at CpG sites are easily mutated and have been implicated in G:C-->A:T transitions in the p53 tumor suppressor gene. We investigated 2 polymorphisms in the MTHFR gene (C677T and A1298C) and their associations with colon tumor characteristics, including acquired mutations in Ki-ras and p53 genes and microsatellite instability (MSI). The study population comprised 1248 colon cancer cases and 1972 controls, who participated in a population-based case-control study and had been analyzed previously for MSI, acquired mutations in Ki-ras, p53, and germline MTHFR polymorphisms. Multivariable-adjusted odds ratios are presented. Overall, MTHFR genotypes were not associated with MSI status or the presence of any p53 or Ki-ras mutation. Individuals with homozygous variant MTHFR genotypes had a significantly reduced risk of G:C-->A:T transition mutations within the p53 gene, yet, as hypothesized, only at CpG-associated sites [677TT vs. 677CC (referent group) OR = 0.4 (95% CI: 0.1-0.8) for CpG-associated sites; OR = 1.5 (0.7-3.6) for non-CpG associated sites]. Genotypes conferring reduced MTHFR activity were associated with a decreased risk of acquired G:C-->A:T mutations within the p53 gene occurring at CpG sites. Consistent with evidence on the phenotypic effect of the MTHFR C677T variant, we hypothesize that this relation may be explained by modestly reduced genomic DNA methylation, resulting in a lower probability of spontaneous deamination of methylated cytosine to thymidine. These results suggest a novel mechanism by which MTHFR polymorphisms can affect the risk of colon cancer.

  12. Targeting myeloid-derived suppressor cells with colony stimulating factor-1 receptor blockade can reverse immune resistance to immunotherapy in indoleamine 2,3-dioxygenase-expressing tumors.

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    Holmgaard, Rikke B; Zamarin, Dmitriy; Lesokhin, Alexander; Merghoub, Taha; Wolchok, Jedd D

    2016-04-01

    Tumor indoleamine 2,3-dioxygenase (IDO) promotes immunosuppression by direct action on effector T cells and Tregs and through recruitment, expansion and activation of myeloid-derived suppressor cells (MDSCs). Targeting of MDSCs is clinically being explored as a therapeutic strategy, though optimal targeting strategies and biomarkers predictive of response are presently unknown. Maturation and tumor recruitment of MDSCs are dependent on signaling through the receptor tyrosine kinase CSF-1R on myeloid cells. Here, we show that MDSCs are the critical cell population in IDO-expressing B16 tumors in mediating accelerated tumor outgrowth and resistance to immunotherapy. Using a clinically relevant drug, we show that inhibition of CSF-1R signaling can functionally block tumor-infiltrating MDSCs and enhance anti-tumor T cell responses. Furthermore, inhibition of CSF-1R sensitizes IDO-expressing tumors to immunotherapy with T cell checkpoint blockade, and combination of CSF-1R blockade with IDO inhibitors potently elicits tumor regression. These findings provide evidence for a critical and functional role for MDSCs on the in vivo outcome of IDO-expressing tumors. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  13. Galectin-3 mediates cross-talk between K-Ras and Let-7c tumor suppressor microRNA.

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    Ran Levy

    Full Text Available BACKGROUND: Galectin-3 (Gal-3 and active (GTP-bound K-Ras contribute to the malignant phenotype of many human tumors by increasing the rate of cell proliferation, survival, and migration. These Gal-3-mediated effects result from a selective binding to K-Ras.GTP, causing increased nanoclustering in the cell membrane and leading to robust Ras signaling. Regulation of the interactions between Gal-3 and active K-Ras is not fully understood. METHODS AND FINDINGS: To gain a better understanding of what regulates the critical interactions between these two proteins, we examined the role of Gal-3 in the regulation of K-Ras by using Gal-3-knockout mouse embryonic-fibroblasts (Gal-3-/- MEFs and/or Gal-3/Gal-1 double-knockout MEFs. We found that knockout of Gal-3 induced strong downregulation (∼60% of K-Ras and K-Ras.GTP. The downregulation was somewhat more marked in the double-knockout MEFs, in which we also detected robust inhibition(∼50% of ERK and Akt activation. These additional effects are probably attributable to inhibition of the weak interactions of K-Ras.GTP with Gal-1. Re-expression of Gal-3 reversed the phenotype of the Gal-3-/- MEFs and dramatically reduced the disappearance of K-Ras in the presence of cycloheximide to the levels seen in wild-type MEFs. Furthermore, phosphorylation of Gal-3 by casein kinase-1 (CK-1 induced translocation of Gal-3 from the nucleus to the cytoplasm and the plasma membrane, leading to K-Ras stabilization accompanied by downregulation of the tumor suppressor miRNA let-7c, known to negatively control K-Ras transcription. CONCLUSIONS: Our results suggest a novel cross-talk between Gal-3-mediated downregulation of let 7c microRNA (which in turn negatively regulates K-Ras transcription and elucidates the association among Gal-3 let-7c and K-Ras transcription/translation, cellular compartmentalization and activity.

  14. Nuclear location of tumor suppressor protein maspin inhibits proliferation of breast cancer cells without affecting proliferation of normal epithelial cells

    Science.gov (United States)

    2014-01-01

    Background Maspin, which is classified as a tumor suppressor protein, is downregulated in many types of cancer. Several studies have suggested potential anti-proliferative activity of maspin as well as sensitizing activity of maspin for therapeutic cytotoxic agents in breast cancer tissue culture and animal models. All of the experimental data gathered so far have been based on studies with maspin localized cytoplasmically, while maspin in breast cancer tumor cells may be located in the cytoplasm, nucleus or both. In this study, the effect of maspin cytoplasmic and nuclear location and expression level on breast cancer proliferation and patient survival was studied. Methods Tissue sections from 166 patients with invasive ductal breast cancer were stained by immunohistochemistry for maspin and Ki-67 protein. The localization and expression level of maspin were correlated with estimated patient overall survival and percent of Ki-67-positive cells. In further studies, we created constructs for transient transfection of maspin into breast cancer cells with targeted cytoplasmic and nuclear location. We analyzed the effect of maspin location in normal epithelial cell line MCF10A and three breast cancer cell lines - MCF-7, MDA-MB-231 and SKBR-3 - by immunofluorescence and proliferation assay. Results We observed a strong positive correlation between moderate and high nuclear maspin level and survival of patients. Moreover, a statistically significant negative relationship was observed between nuclear maspin and Ki-67 expression in patients with invasive ductal breast cancer. Spearman’s correlation analysis showed a negative correlation between level of maspin localized in nucleus and percentage of Ki-67 positive cells. No such differences were observed in cells with cytoplasmic maspin. We found a strong correlation between nuclear maspin and loss of Ki-67 protein in breast cancer cell lines, while there was no effect in normal epithelial cells from breast. The anti

  15. Genetic and Epigenetic Tumor Suppressor Gene Silencing Are Distinct Molecular Phenotypes Driven by Growth Promoting Mutations in Nonsmall Cell Lung Cancer

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    Carmen J. Marsit

    2008-01-01

    Full Text Available Both genetic and epigenetic alterations characterize human nonsmall cell lung cancer (NSCLC, but the biological processes that create or select these alterations remain incompletely investigated. Our hypothesis posits that a roughly reciprocal relationship between the propensity for promoter hypermethylation and a propensity for genetic deletion leads to distinct molecular phenotypes of lung cancer. To test this hypothesis, we examined promoter hypermethylation of 17 tumor suppressor genes, as a marker of epigenetic alteration propensity, and deletion events at the 3p21 region, as a marker of genetic alteration. To model the complex biology between these somatic alterations, we utilized an item response theory model. We demonstrated that tumors exhibiting LOH at greater than 30% of informative alleles in the 3p21 region have a significantly reduced propensity for hypermethylation. At the same time, tumors with activating KRAS mutations showed a significantly increased propensity for hypermethylation of the loci examined, a result similar to what has been observed in colon cancer. These data suggest that NSCLCs have distinct epigenetic or genetic alteration phenotypes acting upon tumor suppressor genes and that mutation of oncogenic growth promoting genes, such as KRAS, is associated with the epigenetic phenotype.

  16. Antihelminthic drug niclosamide inhibits CIP2A and reactivates tumor suppressor protein phosphatase 2A in non-small cell lung cancer cells.

    Science.gov (United States)

    Kim, Myeong-Ok; Choe, Min Ho; Yoon, Yi Na; Ahn, Jiyeon; Yoo, Minjin; Jung, Kwan-Young; An, Sungkwan; Hwang, Sang-Gu; Oh, Jeong Su; Kim, Jae-Sung

    2017-11-15

    Protein phosphatase 2A (PP2A) is a critical tumor suppressor complex responsible for the inactivation of various oncogenes. Recently, PP2A reactivation has emerged asan anticancer strategy. Cancerous inhibitor of protein phosphatase 2A (CIP2A), an endogenous inhibitor of PP2A, is upregulated in many cancer cells, including non-small cell lung cancer (NSCLC) cells. We demonstrated that the antihelminthic drug niclosamide inhibited the expression of CIP2A and reactivated the tumor suppressor PP2A in NSCLC cells. We performed a drug-repurposing screen and identified niclosamide asa CIP2A suppressor in NSCLC cells. Niclosamide inhibited cell proliferation, colony formation, and tumor sphere formation, and induced mitochondrial dysfunction through increased mitochondrial ROS production in NSCLC cells; however, these effects were rescued by CIP2A overexpression, which indicated that the antitumor activity of niclosamide was dependent on CIP2A. We found that niclosamide increased PP2A activity through CIP2A inhibition, which reduced the phosphorylation of several oncogenic proteins. Moreover, we found that a niclosamide analog inhibited CIP2A expression and increased PP2A activity in several types of NSCLC cells. Finally, we showed that other well-known PP2A activators, including forskolin and FTY720, did not inhibit CIP2A and that their activities were not dependent on CIP2A. Collectively, our data suggested that niclosamide effectively suppressed CIP2A expression and subsequently activated PP2A in NSCLC cells. This provided strong evidence for the potential use of niclosamide asa PP2A-activating drug in the clinical treatment of NSCLC. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Moringa oleifera Gold Nanoparticles Modulate Oncogenes, Tumor Suppressor Genes, and Caspase-9 Splice Variants in A549 Cells.

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    Tiloke, Charlette; Phulukdaree, Alisa; Anand, Krishnan; Gengan, Robert M; Chuturgoon, Anil A

    2016-10-01

    Gold nanoparticles (AuNP's) facilitate cancer cell recognition and can be manufactured by green synthesis using nutrient rich medicinal plants such as Moringa oleifera (MO). Targeting dysregulated oncogenes and tumor suppressor genes is crucial for cancer therapeutics. We investigated the antiproliferative effects of AuNP synthesized from MO aqueous leaf extracts (MLAuNP ) in A549 lung and SNO oesophageal cancer cells. A one-pot green synthesis technique was used to synthesise MLAuNP . A549, SNO cancer cells and normal peripheral blood mononuclear cells (PBMCs) were exposed to MLAuNP and CAuNP to evaluate cytotoxicity (MTT assay); apoptosis was measured by phosphatidylserine (PS) externalization, mitochondrial depolarization (ΔΨm) (flow cytometry), caspase-3/7, -9 activity, and ATP levels (luminometry). The mRNA expression of c-myc, p53, Skp2, Fbw7α, and caspase-9 splice variants was determined using qPCR, while relative protein expression of c-myc, p53, SRp30a, Bax, Bcl-2, Smac/DIABLO, Hsp70, and PARP-1 were determined by Western blotting. MLAuNP and CAuNP were not cytotoxic to PBMCs, whilst its pro-apoptotic properties were confirmed in A549 and SNO cells. MLAuNP significantly increased caspase activity in SNO cells while MLAuNP significantly increased PS externalization, ΔΨm, caspase-9, caspase-3/7 activities, and decreased ATP levels in A549 cells. Also, p53 mRNA and protein levels, SRp30a (P = 0.428), Bax, Smac/DIABLO and PARP-1 24 kDa fragment levels were significantly increased. Conversely, MLAuNP significantly decreased Bcl-2, Hsp70, Skp2, Fbw7α, c-myc mRNA, and protein levels and activated alternate splicing with caspase-9a splice variant being significantly increased. MLAuNP possesses antiproliferative properties and induced apoptosis in A549 cells by activating alternate splicing of caspase-9. J. Cell. Biochem. 117: 2302-2314, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  18. Htid-1, the human homolog of the Drosophila melanogaster l(2)tid tumor suppressor, defines a novel physiological role of APC.

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    Kurzik-Dumke, Ursula; Czaja, Joachim

    2007-09-01

    Htid-1, the human counterpart of the Drosophila tumor suppressor gene lethal(2)tumorous imaginal discs (l(2)tid) encodes three splice forms translated into three cytosolic - Tid50, Tid48 and Tid46 - and three mitochondrial - Tid43, Tid40 and Tid38 - proteins. Here we provide evidence for the association of the endogenous Tid50/Tid48 proteins with the adenomatous polyposis coli (APC) tumor suppressor in normal colon epithelium, colorectal cancer cells and mouse NIH3T3 fibroblasts. Using the Glutathione S-transferase binding assay we show that the N-terminal region including the Armadillo domain (ARM) of APC is sufficient to bind the Tid molecules. Using immunoprecipitation and confocal microscopy we show that the two molecular partners complex at defined areas of the cells with further proteins such as Hsp70, Hsc70, Actin, Dvl and Axin. Our data implicate that the formation of the complex is not associated with APC's involvement in beta-Catenin degradation. Furthermore, though it is linked to Actin it is neither associated with regulation of Actin cytoskeleton due to APC's binding to Asef nor to Tid's binding to Ras-GAP. We suggest that the novel complex acts in maintaining APC's availability for its distinct roles in the Wnt signaling important for the cell to take the right decision, either to switch the cascade OFF or ON, thus, to regulate the onset of proliferation of the cells.

  19. Inactivation of the tumor suppressor genes causing the hereditary syndromes predisposing to head and neck cancer via promoter hypermethylation in sporadic head and neck cancers.

    Science.gov (United States)

    Smith, Ian M; Mithani, Suhail K; Mydlarz, Wojciech K; Chang, Steven S; Califano, Joseph A

    2010-01-01

    Fanconi anemia (FA) and dyskeratosis congenita (DC) are rare inherited syndromes that cause head and neck squamous cell cancer (HNSCC). Prior studies of inherited forms of cancer have been extremely important in elucidating tumor suppressor genes inactivated in sporadic tumors. Here, we studied whether sporadic tumors have epigenetic silencing of the genes causing the inherited forms of HNSCC. Using bisulfite sequencing, we investigated the incidence of promoter hypermethylation of the 17 Fanconi- and DC-associated genes in sporadic HNSCC. Genes that only showed methylation in the tumor patients were chosen for quantitative methylation-specific PCR (qMSP) in a set of 45 tumor and 16 normal patients. Three gene promoters showed differences in methylation: FancB (FAAP95, FA core complex), FancJ (BRIP1, DNA Helicase/ATPase), and DKC1 (dyskeratin). Bisulfite sequencing revealed that only FancB and DKC1 showed no methylation in normal patients, yet the presence of promoter hypermethylation in tumor patients. On qMSP, 1/16 (6.25%) of the normal mucosal samples from non-cancer patients and 14/45 (31.1%) of the tumor patients demonstrated hypermethylation of the FancB locus (p < 0.05). These results suggest that inactivation of FancB may play a role in the pathogenesis of sporadic HNSCC.

  20. Repression of human papillomavirus oncogenes in HeLa cervical carcinoma cells causes the orderly reactivation of dormant tumor suppressor pathways

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    Goodwin, Edward C.; DiMaio, Daniel

    2000-01-01

    Most cervical carcinomas express high-risk human papillomaviruses (HPVs) E6 and E7 proteins, which neutralize cellular tumor suppressor function. To determine the consequences of removing the E6 and E7 proteins from cervical cancer cells, we infected HeLa cells, a cervical carcinoma cell line that contains HPV18 DNA, with a recombinant virus that expresses the bovine papillomavirus E2 protein. Expression of the E2 protein resulted in rapid repression of HPV E6 and E7 e...

  1. DC-SCRIPT is a novel regulator of the tumor suppressor gene CDKN2B and induces cell cycle arrest in ERα-positive breast cancer cells.

    Science.gov (United States)

    Ansems, Marleen; Søndergaard, Jonas Nørskov; Sieuwerts, Anieta M; Looman, Maaike W G; Smid, Marcel; de Graaf, Annemarie M A; de Weerd, Vanja; Zuidscherwoude, Malou; Foekens, John A; Martens, John W M; Adema, Gosse J

    2015-02-01

    Breast cancer is one of the most common causes of cancer-related deaths in women. The estrogen receptor (ERα) is well known for having growth promoting effects in breast cancer. Recently, we have identified DC-SCRIPT (ZNF366) as a co-suppressor of ERα and as a strong and independent prognostic marker in ESR1 (ERα gene)-positive breast cancer patients. In this study, we further investigated the molecular mechanism on how DC-SCRIPT inhibits breast cancer cell growth. DC-SCRIPT mRNA levels from 190 primary ESR1-positive breast tumors were related to global gene expression, followed by gene ontology and pathway analysis. The effect of DC-SCRIPT on breast cancer cell growth and cell cycle arrest was investigated using novel DC-SCRIPT-inducible MCF7 breast cancer cell lines. Genome-wide expression profiling of DC-SCRIPT-expressing MCF7 cells was performed to investigate the effect of DC-SCRIPT on cell cycle-related gene expression. Findings were validated by real-time PCR in a cohort of 1,132 ESR1-positive breast cancer patients. In the primary ESR1-positive breast tumors, DC-SCRIPT expression negatively correlated with several cell cycle gene ontologies and pathways. DC-SCRIPT expression strongly reduced breast cancer cell growth in vitro, breast tumor growth in vivo, and induced cell cycle arrest. In addition, in the presence of DC-SCRIPT, multiple cell cycles related genes were differentially expressed including the tumor suppressor gene CDKN2B. Moreover, in 1,132 primary ESR1-positive breast tumors, DC-SCRIPT expression also correlated with CDKN2B expression. Collectively, these data show that DC-SCRIPT acts as a novel regulator of CDKN2B and induces cell cycle arrest in ESR1-positive breast cancer cells.

  2. Aminoacyl-tRNA synthetase-interacting multifunctional protein 1 suppresses tumor growth in breast cancer-bearing mice by negatively regulating myeloid-derived suppressor cell functions.

    Science.gov (United States)

    Hong, Hye-Jin; Lim, Hui Xuan; Song, Ju Han; Lee, Arim; Kim, Eugene; Cho, Daeho; Cohen, Edward P; Kim, Tae Sung

    2016-01-01

    Myeloid-derived suppressor cells (MDSCs) are one of the most important cell types that contribute to negative regulation of immune responses in the tumor microenvironment. Recently, aminoacyl-tRNA synthetase-interacting multifunctional protein 1 (AIMP1), a novel pleiotropic cytokine, was identified as an antitumor protein that inhibits angiogenesis and induces antitumor responses. However, the effect of AIMP1 on MDSCs in the tumor environment remains unclear. In the present study, we demonstrated that AIMP1 significantly inhibited tumor growth in 4T1 breast cancer-bearing mice and reduced MDSCs population of tumor sites and spleens of tumor-bearing mice. AIMP1 reduced expansion of MDSCs from bone marrow-derived cells in the tumor-conditioned media. AIMP1 also negatively regulated suppressive activities of MDSCs by inhibiting IL-6 and NO production, and Arg-1 expression. Furthermore, treatment of breast cancer-bearing mice with AIMP1 decreased the capacity of MDSCs to suppress T cell proliferation and Treg cell induction. Western blot and inhibition experiments showed that downregulation of MDSCs functions by AIMP1 may result from attenuated activation of STATs, Akt, and ERK. These findings indicate that AIMP1 plays an essential role in negative regulation of suppressive functions of MDSCs. Therefore, it has a significant potential as a therapeutic agent for cancer treatment.

  3. Cisplatin-induced renal toxicity via tumor necrosis factor-α, interleukin 6, tumor suppressor P53, DNA damage, xanthine oxidase, histological changes, oxidative stress and nitric oxide in rats: protective effect of ginseng.

    Science.gov (United States)

    Yousef, Mokhtar I; Hussien, Hend M

    2015-04-01

    Cisplatin is an effective chemotherapeutic agent successfully used in the treatment of a wide range of solid tumors, while its usage is limited due to its nephrotoxicity. The present study was undertaken to examine the effectiveness of ginseng to ameliorate the renal nephrotoxicity, damage in kidney genomic DNA, tumor necrosis factor-α, interleukin 6, tumor suppressor P53, histological changes and oxidative stress induced by cisplatin in rats. Cisplatin caused renal damage, including DNA fragmentation, upregulates gene expression of tumor suppressor protein p53 and tumor necrosis factor-α and IL-6. Cisplatin increased the levels of kidney TBARS, xanthine oxidase, nitric oxide, serum urea and creatinine. Cisplatin decreased the activities of antioxidant enzymes (GST, GPX, CAT and SOD), ATPase and the levels of GSH. A microscopic examination showed that cisplatin caused kidney damage including vacuolization, severe necrosis and degenerative changes. Ginseng co-treatment with cisplatin reduced its renal damage, oxidative stress, DNA fragmentation and induced DNA repair processes. Also, ginseng diminished p53 activation and improved renal cell apoptosis and nephrotoxicity. It can be concluded that, the protective effects of ginseng against cisplatin induced-renal damage was associated with the attenuation of oxidative stress and the preservation of antioxidant enzymes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Epstein–Barr virus nuclear antigen 3C interact with p73: Interplay between a viral oncoprotein and cellular tumor suppressor

    Energy Technology Data Exchange (ETDEWEB)

    Sahu, Sushil Kumar; Mohanty, Suchitra; Kumar, Amit [Division of Infectious Disease Biology, Institute of Life Sciences, Nalco Square, Chandrasekharpur, Bhubaneswar 751023 (India); Kundu, Chanakya N. [School of Biotechnology, KIIT University, Bhubaneswar (India); Verma, Subhash C. [Department of Microbiology and Immunology, University of Nevada, School of Medicine, Reno, NV 89557 (United States); Choudhuri, Tathagata, E-mail: tatha@ils.res.in [Division of Infectious Disease Biology, Institute of Life Sciences, Nalco Square, Chandrasekharpur, Bhubaneswar 751023 (India); Department of Biotechnology, Siksha Bhavana, Visva Bharati, Santiniketan, Bolpur (India)

    2014-01-05

    The p73 protein has structural and functional homology with the tumor suppressor p53, which plays an important role in cell cycle regulation, apoptosis, and DNA repair. The p73 locus encodes both a tumor suppressor (TAp73) and a putative oncogene (ΔNp73). p73 May play a significant role in p53-deficient lymphomas infected with Epstein–Barr virus (EBV). EBV produces an asymptomatic infection in the majority of the global population, but it is associated with several human B-cell malignancies. The EBV-encoded Epstein–Barr virus nuclear antigen 3C (EBNA3C) is thought to disrupt the cell cycle checkpoint by interacting directly with p53 family proteins. Doxorubicin, a commonly used chemotherapeutic agent, induces apoptosis through p53 and p73 signaling such that the lowΔNp73 level promotes the p73-mediated intrinsic pathway of apoptosis. In this report, we investigated the mechanism by which EBV infection counters p73α-induced apoptosis through EBNA3C. - Highlights: • EBV-encoded EBNA3C suppresses doxorubicin-induced apoptosis in B-cell lymphomas. • EBNA3C binds to p73 to suppress its apoptotic effect. • EBNA3C maintains latency by regulating downstream mitochondrial pathways.

  5. Loss of the tumor suppressor Pten promotes proliferation of Drosophila melanogaster cells in vitro and gives rise to continuous cell lines.

    Directory of Open Access Journals (Sweden)

    Steven E Justiniano

    Full Text Available In vivo analysis of Drosophila melanogaster has enhanced our understanding of many biological processes, notably the mechanisms of heredity and development. While in vivo analysis of mutants has been a strength of the field, analyzing fly cells in culture is valuable for cell biological, biochemical and whole genome approaches in which large numbers of homogeneous cells are required. An efficient genetic method to derive Drosophila cell lines using expression of an oncogenic form of Ras (Ras(V12 has been developed. Mutations in tumor suppressors, which are known to cause cell hyperproliferation in vivo, could provide another method for generating Drosophila cell lines. Here we screened Drosophila tumor suppressor mutations to test if they promoted cell proliferation in vitro. We generated primary cultures and determined when patches of proliferating cells first emerged. These cells emerged on average at 37 days in wild-type cultures. Using this assay we found that a Pten mutation had a strong effect. Patches of proliferating cells appeared on average at 11 days and the cultures became confluent in about 3 weeks, which is similar to the timeframe for cultures expressing Ras(V12. Three Pten mutant cell lines were generated and these have now been cultured for between 250 and 630 cell doublings suggesting the life of the mutant cells is likely to be indefinite. We conclude that the use of Pten mutants is a powerful means to derive new Drosophila cell lines.

  6. Functional genetic screen for genes involved in senescence: role of Tid1, a homologue of the Drosophila tumor suppressor l(2)tid, in senescence and cell survival.

    Science.gov (United States)

    Tarunina, Marina; Alger, Lynsey; Chu, Grace; Munger, Karl; Gudkov, Andrei; Jat, Parmjit S

    2004-12-01

    We performed a genetic suppressor element screen to identify genes whose inhibition bypasses cellular senescence. A normalized library of fragmented cDNAs was used to select for elements that promote immortalization of rat embryo fibroblasts. Fragments isolated by the screen include those with homology to genes that function in intracellular signaling, cellular adhesion and contact, protein degradation, and apoptosis. They include mouse Tid1, a homologue of the Drosophila tumor suppressor gene l(2)tid, recently implicated in modulation of apoptosis as well as gamma interferon and NF-kappaB signaling. We show that GSE-Tid1 enhances immortalization by human papillomavirus E7 and simian virus 40 T antigen and cooperates with activated ras for transformation. Expression of Tid1 is upregulated upon cellular senescence in rat and mouse embryo fibroblasts and premature senescence of REF52 cells triggered by activated ras. In accordance with this, spontaneous immortalization of rat embryo fibroblasts is suppressed upon ectopic expression of Tid1. Modulation of endogenous Tid1 activity by GSE-Tid1 or Tid1-specific RNA interference alleviates the suppression of tumor necrosis factor alpha-induced NF-kappaB activity by Tid1. We also show that NF-kappaB sequence-specific binding is strongly downregulated upon senescence in rat embryo fibroblasts. We therefore propose that Tid1 contributes to senescence by acting as a repressor of NF-kappaB signaling.

  7. Poor prognosis of colorectal cancer in patients over 80 years old is associated with down-regulation of tumor suppressor genes.

    Science.gov (United States)

    Nagaoka, Sakae; Shiraishi, Junichi; Utsuyama, Masanori; Seki, Sachiko; Takemura, Tamiko; Kitagawa, Masanobu; Sawabe, Motoji; Takubo, Kaiyo; Hirokawa, Katsuiku

    2003-07-01

    GOALS, BACKGROUND: The elderly population has been increasing during the last half a century and it would be important to know how aging influences the occurrence and biologic behavior of cancers. We investigated clinicopathologic characteristics of colorectal cancer in 1354 patients who underwent colorectal cancer resection and compared the results between extremely elderly patients (over 80 years old) and middle-aged/elderly patients (40 to less than 80 years old). Furthermore, we also examined expression of tumor suppressor genes and Cox-2 using frozen samples of colorectal cancer obtained from 62 patients ranging in age from 45 to 87 years. The results obtained in the extremely aged patients were: (1) higher ratio of women, (2) higher incidence at the proximal site, (3) higher incidence of cases with deeper invasion, (4) higher incidence of cases with lymph node metastasis (5) poorer survival rate as compared with middle-aged/elderly patients, and (6) lower mRNA expression levels of p27 and p53. These findings taken together suggest that poor prognosis of colorectal cancer in patients over 80 years is associated with down-regulation of mRNA expression of some tumor suppressor genes.

  8. The long non-coding RNA H19-derived miR-675 modulates human gastric cancer cell proliferation by targeting tumor suppressor RUNX1

    Energy Technology Data Exchange (ETDEWEB)

    Zhuang, Ming [Department of Oncology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu (China); Department of Oncology, The First People’s Hospital of Lianyungang, Lianyungang, Jiangsu (China); Gao, Wen; Xu, Jing; Wang, Ping [Department of Oncology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu (China); Shu, Yongqian, E-mail: shuyongqian39000@163.com [Department of Oncology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu (China)

    2014-06-06

    Graphical abstract: - Highlights: • H19 regulates gastric cancer cell proliferation phenotype via miR-675. • MiR-675 modulates cell proliferation of gastric cancer cells by targeting tumor suppressor RUNX1. • The H19/miR-675/RUNX1 axis plays an important role in the tumorigenesis of gastric cancer. - Abstract: The lncRNA H19 has been recently shown to be upregulated and play important roles in gastric cancer tumorigenesis. However, the precise molecular mechanism of H19 and its mature product miR-675 in the carcinogenesis of gastric cancer remains unclear. In this study, we found that miR-675 was positively expressed with H19 and was a pivotal mediator in H19-induced gastric cancer cell growth promotion. Subsequently, the tumor suppressor Runt Domain Transcription Factor1 (RUNX1) was confirmed to be a direct target of miR-675 using a luciferase reporter assay and Western blotting analyses. A series of rescue assays indicated that RUNX1 mediated H19/miR-67-induced gastric cancer cell phenotypic changes. Moreover, the inverse relationship between the expression of RUNX1 and H19/miR-675 was also revealed in gastric cancer tissues and gastric cancer cell lines. Taken together, our study demonstrated that the novel pathway H19/miR-675/RUNX1 regulates gastric cancer development and may serve as a potential target for gastric cancer therapy.

  9. SLIT2, a human homologue of the Drosophila Slit2 gene, has tumor suppressor activity and is frequently inactivated in lung and breast cancers.

    Science.gov (United States)

    Dallol, Ashraf; Da Silva, Nancy Fernandes; Viacava, Paolo; Minna, John D; Bieche, Ivan; Maher, Eamonn R; Latif, Farida

    2002-10-15

    Slit2 plays a vital role in axon guidance by signaling through Robo receptors. Recent evidence suggests that Slit2 protein may function in other settings because human and Xenopus Slit2 has been shown to inhibit leukocyte chemotaxis. SLIT2 protein is a putative ligand for the ROBO receptors. We recently demonstrated that ROBO1 is inactivated by promoter region hypermethylation in cancers; furthermore, tumor suppressor activity has not been shown. Thus, the importance of ROBO1 inactivation in human cancer is uncertain. Therefore, we investigated the status of SLIT2 located at 4p15.2 in lung and breast cancers. Although somatic SLIT2 mutations were not detected, epigenetic inactivation was common. SLIT2 promoter methylation was detected in 59% of breast cancer, 77% of non-small cell lung cancer, and 55% of small cell lung cancer cell lines. In these tumor lines, SLIT2 expression was restored by treatment with a demethylating agent. SLIT2 promoter methylation was detected in 43% of breast cancer, 53% of non-small cell lung cancer, and 36% of small cell lung cancer primary tumors. The majority of methylated tumors demonstrated allelic loss at 4p15.2. In addition, SLIT2 expression was down-regulated in methylated breast tumors, relative to normal control, as demonstrated by quantitative real-time reverse transcription-PCR. Overexpression of SLIT2 suppressed >70% of colony growth in each of three breast tumor lines (with either absent or low SLIT2 expression). Because SLIT2 is primarily a secreted protein, SLIT2-conditioned medium suppressed the growth of several breast cancer lines (with absent or weak SLIT2expression) by 26-51% but had no significant effect on a breast tumor cell line that expresses normal levels of SLIT2. These findings demonstrate that SLIT2 is frequently inactivated in lung and breast cancer by promoter region hypermethylation and allele loss and is an excellent candidate for the lung and breast tumor suppressor gene previously mapped to 4p15.2.

  10. [The number of myeloid-derived suppressor cells in the peripheral blood and tumor tissues in patients with gastric cancer and its clinical significance].

    Science.gov (United States)

    Xia, Rui; Wang, Feng; Gao, Tengfei; Wen, Wen; Lu, Binfeng; Zhu, Yibei; Zhang, Xueguang

    2014-07-01

    To investigate the number of myeloid-derived suppressor cells (MDSCs) in peripheral blood, tumor tissue and para-tumor normal tissues in patients with gastric cancer in an attempt to explore the relationship between MDSCs expression and clinicopathologic characteristics. Peripheral blood was collected from 62 gastric cancer patients and 20 healthy volunteers (HC group). Gastric cancer tissues and adjacent normal tissues were obtained from 12 of the 62 gastric cancer patients. HLA-DR⁻ CD33⁺ CD11b⁺ MDSCs were analyzed by flow cytometry. Student's t-test, One-way ANOVA and Mann-Whitney U test were used to explore the correlation between MDSCs expression in peripheral blood and the depth of tumor invasion, degree of differentiation, TNM stage and lymph node metastasis. Compare with the HC group, the number of MDSCs in peripheral blood of newly-diagnosed gastric cancer patients was higher (Pnumber of MDSCs in peripheral blood of gastric cancer patients was significantly associated with the depth of invasion, degree of differentiation, TNM stage and lymph node metastasis (Pcancer tissues was obviously higher than that of the adjacent tissues in the same patient. The number of MDSCs in peripheral blood from recurrent/metastasis group was obviously higher than that from non-recurrent/metastasis group (Ppatients with gastric cancer. MDSCs expression in peripheral blood of gastric cancer patients was closely associated with tumor malignant degree and tumor recurrence/metastasis.

  11. Candidate Tumor-Suppressor Gene DLEC1 Is Frequently Downregulated by Promoter Hypermethylation and Histone Hypoacetylation in Human Epithelial Ovarian Cancer

    Directory of Open Access Journals (Sweden)

    Joseph Kwong

    2006-04-01

    Full Text Available Suppression of ovarian tumor growth by chromosome 3p was demonstrated in a previous study. Deleted in Lung and Esophageal Cancer 1 (DLEC1 on 3p22.3 is a candidate tumor suppressor in lung, esophageal, and renal cancers. The potential involvement of DLEC1 in epithelial ovarian cancer remains unknown. In the present study, DLEC1 downregulation was found in ovarian cancer cell lines and primary ovarian tumors. Focus-expressed DLEC1 in two ovarian cancer cell lines resulted in 41% to 52% inhibition of colony formation. No chromosomal loss of chromosome 3p22.3 in any ovarian cancer cell line or tissue was found. Promoter hypermethylation of DLEC1 was detected in ovarian cancer cell lines with reduced DLEC1 transcripts, whereas methylation was not detected in normal ovarian epithelium and DLEC1-expressing ovarian cancer cell lines. Treatment with demethylating agent enhanced DLEC1 expression in 90% (9 of 10 of ovarian cancer cell lines. DLEC1 promoter methylation was examined in 13 high-grade ovarian tumor tissues with DLEC1 downregulation, in which 54% of the tumors showed DLEC1 methylation. In addition, 80% of ovarian cancer cell lines significantly upregulated DLEC1 transcripts after histone deacetylase inhibitor treatment. Therefore, our results suggested that DLEC1 suppressed the growth of ovarian cancer cells and that its downregulation was closely associated with promoter hypermethylation and histone hypoacetylation.

  12. Discovery of Prostate Cancer Tumor Suppressors and Mediators of MDV3100 Resistance Through in Vivo RNA Interference Screen

    Science.gov (United States)

    2015-11-01

    RNA Interference Screen PRINCIPAL INVESTIGATOR: Kamlesh K Yadav CONTRACTING ORGANIZATION: Sloan Kettering Institute for Cancer Research New...Suppressors and Mediators of MDV3100 Resistance through in Vivo RNA Interference Screen 5b. GRANT NUMBER W81XWH-13-1-0084 5c. PROGRAM ELEMENT NUMBER 6... rna interference screens, STARR consortium retreat, CSHL, NY 8 o Website(s) or other Internet site(s) o Technologies or techniques o

  13. Topological transition of the parametric expression site of tumor suppressor inactivation as a marker evidence of environmental hormone-oriented cancer risk increase.

    Science.gov (United States)

    Kodama, M; Murakami, M; Kodama, T

    1999-08-01

    The present study is an extension of our recent study in which we attempted statistical analysis of the data assembly of age-adjusted incidence rates (AAIRs) of a tumor without topological data manipulation for each of 20 individual tumors in scope, for each of 6 cancer registration areas in space, and for a period of early 1960's to mid 1980's in time. This time, a data assembly of log AAIR changes in time and space first passed through the process of topological data manipulation, and then underwent the sequential regression analysis so that we could assess the fitness of log AAIR changes either in space or in time to the equilibrium model of the law of mass action from the viewpoint of the interaction between oncogene activation and tumor suppressor gene inactivation. For the sake of comparison, the fitness of the cancer risk data to the equilibrium model was assessed in the framework of 3 sets of coordinates: a) the original (x org, y org) coordinates in which most of the log AAIR data assemblies in their data variations were classified as the oncogene activation type in the field of centripetal force (r seq=-1.000). b) The rect (X rect, Y rect) coordinates in which the log AAIR data assemblies were very often classified as the tumor suppressor gene inactivation type in the field of centrifugal force (r seq=+1.000). c) The para (X para, Y para) coordinates in which the log AAIR data assemblies were mostly classified as the intermediate type as regards the fitness to the equilibrium model. The rect-coordinates and the para-coordinates, 2 variants of angular rotation of the original coordinates, were so designed as to allow their X-axes to run each at a right angle and parallel to the regression line of the original pair data block. The results obtained were as follows: a) poor fitness of the log AAIR changes in space to the equilibrium model in the rect-coordinates was found in male breast cancer, male thyroid cancer, female esophageal cancer, female laryngeal

  14. Immunohistochemical observations on tumor suppressor gene p53 status in mouse fibrosarcoma following in-vivo photodynamic therapy: the role of xanthine oxidase activity

    Science.gov (United States)

    Ziolkowski, Piotr P.; Symonowicz, Krzysztof; Milnerowicz, Artur; Osiecka, Beata J.

    1997-12-01

    Tumor suppressor gene p53 expression in a mouse fibrosarcoma following in-vivo photodynamic therapy has been studied using the immunohistochemical method. Photodynamic treatment involved injections of the well known sensitizer -- hematoporphyrin derivative at the doses 1.25 and 2.5 mg/kg of body weight and irradiations at the doses 25 and 50 J/sq cm. Glass slide preparations from PDT-treated tumors were obtained at different time points (15, 60 minutes, 2 and 24 hours) after therapy, subsequently stained for wild type/mutant p53, and assessed for positive reaction. High PDT doses (HpD -- 2.5 mg/kg; light dose -- 50 J/sq cm) correlated with decreased expression of p53 in tumor cells. The other part of the study was directed to measure the xanthine oxidase (XO) activity in the tumor cells. PDT included injections of HpD and light exposure at the same doses as for p53 study. We observed a complete inhibition of the enzyme activity. The slight increase in XO activity was found following treatment with either light or HpD alone.

  15. The chromatin remodelling factor BRG1 is a novel binding partner of the tumor suppressor p16INK4a

    Directory of Open Access Journals (Sweden)

    Mann Graham J

    2009-01-01

    Full Text Available Abstract Background CDKN2A/p16INK4a is frequently altered in human cancers and it is the most important melanoma susceptibility gene identified to date. p16INK4a inhibits pRb phosphorylation and induces cell cycle arrest, which is considered its main tumour suppressor function. Nevertheless, additional activities may contribute to the tumour suppressor role of p16INK4a and could help explain its specific association with melanoma predisposition. To identify such functions we conducted a yeast-two-hybrid screen for novel p16INK4a binding partners. Results We now report that p16INK4a interacts with the chromatin remodelling factor BRG1. We investigated the cooperative roles of p16INK4a and BRG1 using a panel of cell lines and a melanoma cell model with inducible p16INK4a expression and BRG1 silencing. We found evidence that BRG1 is not required for p16INK4a-induced cell cycle inhibition and propose that the p16INK4a-BRG1 complex regulates BRG1 chromatin remodelling activity. Importantly, we found frequent loss of BRG1 expression in primary and metastatic melanomas, implicating this novel p16INK4a binding partner as an important tumour suppressor in melanoma. Conclusion This data adds to the increasing evidence implicating the SWI/SNF chromatin remodelling complex in tumour development and the association of p16INK4a with chromatin remodelling highlights potentially new functions that may be important in melanoma predisposition and chemoresistance.

  16. Blockade of A2b Adenosine Receptor Reduces Tumor Growth and Immune Suppression Mediated by Myeloid-Derived Suppressor Cells in a Mouse Model of Melanoma

    Directory of Open Access Journals (Sweden)

    Raffaella Iannone

    2013-12-01

    Full Text Available The A2b receptor (A2bR belongs to the adenosine receptor family. Emerging evidence suggest that A2bR is implicated in tumor progression in some murine tumor models, but the therapeutic potential of targeting A2bR in melanoma has not been examined. This study first shows that melanoma-bearing mice treated with Bay 60-6583, a selective A2bR agonist, had increased melanoma growth. This effect was associated with higher levels of immune regulatory mediators interleukin-10 (IL-10 and monocyte chemoattractant protein 1 (MCP-1 and accumulation of tumor-associated CD11b positive Gr1 positive cells (CD11b+Gr1+ myeloid-derived suppressor cells (MDSCs. Depletion of CD11b+Gr1+ cells completely reversed the protumor activity of Bay 60-6583. Conversely, pharmacological blockade of A2bR with PSB1115 reversed immune suppression in the tumor microenvironment, leading to a significant melanoma growth delay. PSB1115 treatment reduced both levels of IL-10 and MCP-1 and CD11b+Gr1+ cell number in melanoma lesions. These effects were associated with higher frequency of tumor-infiltrating CD8 positive (CD8+ T cells and natural killer T (NKT cells and increased levels of T helper 1 (Th1-like cytokines. Adoptive transfer of CD11b+Gr1+ cells abrogated the antitumor activity of PSB1115. These data suggest that the antitumor activity of PSB1115 relies on its ability to lower accumulation of tumor-infiltrating MDSCs and restore an efficient antitumor T cell response. The antitumor effect of PSB1115 was not observed in melanoma-bearing nude mice. Furthermore, PSB1115 enhanced the antitumor efficacy of dacarbazine. These data indicate that A2bR antagonists such as PSB1115 should be investigated as adjuvants in the treatment of melanoma.

  17. Expression of Vascular Endothelial Growth Factor in Ovarian Cancer Inhibits Tumor Immunity through the Accumulation of Myeloid-Derived Suppressor Cells.

    Science.gov (United States)

    Horikawa, Naoki; Abiko, Kaoru; Matsumura, Noriomi; Hamanishi, Junzo; Baba, Tsukasa; Yamaguchi, Ken; Yoshioka, Yumiko; Koshiyama, Masafumi; Konishi, Ikuo

    2017-01-15

    High VEGF expression in ovarian cancer is an unfavorable prognostic factor. However, the role of VEGF in tumor immunity remains unclear. Here, we examined the impact of VEGF on local immunity, including induction of myeloid-derived suppressor cells (MDSC), in ovarian cancer. High-grade serous ovarian cancer (HGSOC) cases were analyzed by gene expression microarray and IHC for VEGF, CD8, and CD33. VEGF receptor (VEGFR) 1 and VEGFR2 expression levels on MDSCs were analyzed in a mouse model, and the direct effects of VEGF-A on MDSC expansion were investigated. Gr1(+) MDSCs and lymphocyte frequencies were analyzed in control tumors and tumors derived from cells harboring short hairpin RNA targeting Vegf-a. In addition, the therapeutic effects of anti-Gr-1 antibodies were examined. Microarray analysis revealed the upregulation of several myeloid cell chemoattractants and the downregulation of lymphocyte-related pathways in cases with high VEGF expression. In immunohistochemical analysis, VEGF expression in peritoneal dissemination correlated with MDSC infiltration. Cases with high MDSC infiltration, which was inversely correlated with intratumoral CD8(+) T-cell infiltration, exhibited shorter overall survival. In a mouse model, intratumoral MDSCs expressed both VEGFR1 and VEGFR2. MDSC migration and differentiation were augmented by VEGF signaling. Vegf-a knockdown in tumor cells resulted in decreased MDSC infiltration and increased CD8(+) T-cell infiltration. Moreover, treatment with anti-Gr-1 antibodies delayed the growth of control tumors, whereas Vegf-a-knockdown tumors were unaffected by anti-Gr-1 antibody treatment. VEGF expression in ovarian cancer induced MDSCs, inhibited local immunity, and contributed to poor prognosis. Clin Cancer Res; 23(2); 587-99. ©2016 AACR. ©2016 American Association for Cancer Research.

  18. Activating transcription factor-3 (ATF3 functions as a tumor suppressor in colon cancer and is up-regulated upon heat-shock protein 90 (Hsp90 inhibition

    Directory of Open Access Journals (Sweden)

    Dietmeier Wolfgang

    2010-12-01

    Full Text Available Abstract Background Activating transcription factor-3 (ATF3 is involved in the complex process of cellular stress response. However, its exact role in cancer is discussed controversially because both tumor suppressive and oncogenic effects have been described. Here we followed-up on our previous observation that inhibition of Hsp90 may increase ATF3 expression and sought to determine the role of ATF3 in colon cancer. Methods Regulation of ATF3 was determined in cancer cells using signaling inhibitors and a heat-shock protein-90 (Hsp90 antagonist. Human HCT116 cancer cells were stably transfected with an ATF3-shRNA or a luciferase-shRNA expression plasmid and alterations in cell motility were assessed in migration assays. The impact of ATF3 down-regulation on cancer growth and metastasis were investigated in a subcutaneous tumor model, a model of hepatic tumor growth and in a model of peritoneal carcinomatosis. Human colon cancer tissues were analyzed for ATF3 expression. Results The results show that therapeutic Hsp90 inhibition substantially up-regulates the expression of ATF3 in various cancer cells, including colon, gastric and pancreatic cancer. This effect was evident both in vitro and in vivo. RNAi mediated knock-down of ATF3 in HCT116 colon cancer cells significantly increased cancer cell migration in vitro. Moreover, in xenogenic mouse models, ATF3 knock-down promoted subcutaneous tumor growth and hepatic metastasis, as well as peritoneal carcinomatosis. Importantly, ATF3 expression was lower in human colon cancer specimens, as compared to corresponding normal surrounding tissues, suggesting that ATF3 may represent a down-regulated tumor suppressor in colon cancer. Conclusion In conclusion, ATF3 down-regulation in colon cancer promotes tumor growth and metastasis. Considering that blocking Hsp90 induces ATF3 expression, Hsp90 inhibition may represent a valid strategy to treat metastatic colon cancer by up-regulating this anti

  19. Transcriptional Regulation of the p53 Tumor Suppressor Gene in S-Phase of the Cell-Cycle and the Cellular Response to DNA Damage

    Directory of Open Access Journals (Sweden)

    David Reisman

    2012-01-01

    Full Text Available The p53 tumor suppressor induces the transcription of genes that negatively regulate progression of the cell cycle in response to DNA damage or other cellular stressors and thus participates in maintaining genome stability. Numerous studies have demonstrated that p53 transcription is activated before or during early S-phase in cells progressing from G0/G1 into S-phase through the combined action of two DNA-binding factors RBP-Jκ and C/EBPβ-2. Here, we review evidence that this induction occurs to provide available p53 mRNA in order to prepare the cell for DNA damage in S-phase, this ensuring a rapid response to DNA damage before exiting this stage of the cell cycle.

  20. miR-32 functions as a tumor suppressor and directly targets SOX9 in human non–small cell lung cancer [Retraction

    Directory of Open Access Journals (Sweden)

    Zhu D

    2016-10-01

    Full Text Available The Editor-in-Chief and Publisher of OncoTargets and Therapy have been alerted to unacceptable levels of duplication with another published paper: Zhu D, Chen H, Yang X, Chen W, Wang L, Xu J and Yu L. Decreased microRNA-224 and its clinical significance in non-small cell lung cancer patients. Diagnostic Pathology. 9;198:2014.Accordingly, we retract Zhu D, Chen H, Yang X, Chen W, Wang L, Xu J, Yu L. miR-32 functions as a tumor suppressor and directly targets SOX9 in human non–small cell lung cancer. OncoTargets and Therapy. 2015;8:1773–1783. This Retraction relates to 

  1. Multi-gene epigenetic silencing of tumor suppressor genes in T-cell lymphoma cells; delayed expression of the p16 protein upon reversal of the silencing

    DEFF Research Database (Denmark)

    Nagasawa, T; Zhang, Q; Raghunath, P N

    2006-01-01

    )-expressing T-cell lymphomas. p16 gene was epigenetically silenced in all but one of the 10 malignant T-cell lines examined, p15 gene silenced in roughly half of the lines, and p14 was the least frequently affected. Extensive methylation of the p16 promoter was seen in six out of 10 cutaneous T-cell lymphoma...... promoter demethylation and required up to 3 weeks to occur, seemingly reflecting late activation of the p16 gene. These findings indicate that epigenetic silencing affects in T-cell malignancies, often simultaneously, several tumor suppressor genes that impact on key cell functions. The observed...... differential silencing of p16 and p14, and to a lesser degree p15 gene, indicates that the silencing is governed by precise, promoter region-specific mechanisms. The study provides also further rationale for treatment of at least some types of T-cell lymphomas with DNA methyltransferase inhibitors to target...

  2. Glucose Restriction Combined with Autophagy Inhibition and Chemotherapy in HCT 116 Spheroids Decreases Cell Clonogenicity and Viability Regulated by Tumor Suppressor Genes.

    Science.gov (United States)

    Schroll, Monica M; LaBonia, Gabriel J; Ludwig, Katelyn R; Hummon, Amanda B

    2017-08-04

    Drug resistance is a prevalent phenomenon that decreases the efficacy of cancer treatments and contributes to cancer progression and metastasis. Weakening drug-resistant cancer cells prior to chemotherapy is a potential strategy to combat chemoresistance. One approach to damage resistant cancer cells is modulation of nutritional intake. The combination of nutrient restriction with targeted compound treatment results in pronounced molecular changes. This study provides valuable information about augmenting existing chemotherapeutic regimes with simultaneous glucose restriction and autophagy inhibition in colorectal cancer cells. In this study, we explore the chemical pathways that drive the cellular response to nutrient restriction, autophagy inhibition, and the chemotherapy irinotecan using global quantitative proteomics and imaging mass spectrometry. We determined that significant pathways were altered including autophagy and metabolism via glycolysis, gluconeogenesis, and sucrose degradation. We also found that period circadian clock 2 (PER2), a tumor suppressor protein, was significantly up-regulated only when glucose was restricted with autophagy inhibition and chemotherapy. The upstream regulators of these differentially regulated pathways were determined to have implications in cancer, showing an increase in tumor suppressor proteins and a decrease in nuclear protein 1 (NUPR1) an important protein in chemoresistance. We also evaluated the phenotypic response of these cells and discovered autophagy inhibition and chemotherapy treatment increased apoptosis and decreased cell clonogenicity and viability. When glucose restriction was combined with autophagy inhibition and chemotherapy, all of the phenotypic results were intensified. In sum, our results indicate that glucose metabolism is of great importance in the ability of cancer cells to survive chemotherapy. By weakening cancer cells with glucose restriction and autophagy inhibition prior to chemotherapy

  3. Tumor suppressor p53 induces apoptosis of host lymphocytes experimentally infected by Leishmania major, by activation of Bax and caspase-3: a possible survival mechanism for the parasite.

    Science.gov (United States)

    Moshrefi, Mozhgan; Spotin, Adel; Kafil, Hossein Samadi; Mahami-Oskouei, Mahmoud; Baradaran, Behzad; Ahmadpour, Ehsan; Mansoori, Behzad

    2017-08-01

    Apoptosis of infected host macrophages by Leishmania spp. is mainly addressed as one of the survival mechanisms of the parasite. However, there is no eligible data about whether tumor suppressor p53 could induce the apoptosis of host lymphocytes-treated Leishmania major via the mitochondrial intrinsic pathway. In this study, the amastigotes of L. major obtained from ten cutaneous leishmaniases (CL) patients were separately isolated and cultured in N.N.N and RPMI 1640 media. L. major was definitely confirmed by targeting Cyt b gene following sequencing. Subsequently, 2-3 × 106 lymphocytes obtained from ten healthy individuals were isolated and co-cultured with 1-2 × 106 L. major promastigotes. Following 6 h of exposure time, the enzymatic activity of caspase-3 was determined by fluorometric assay in each L. major-treated lymphocytes and cell control (only lymphocyte). The mRNA expressions of Bax, Bcl-2, p53, and caspase-3 genes were assessed by quantitative real-time-PCR analysis following 6 to 9 h of exposure times. The Bcl-2 mRNA expression in L. major-treated lymphocytes was 100-fold down-regulated relative to cell control. The mRNA expressions of p53 and caspase-3 were over-expressed 1.8- and 3.2-fold up-regulated relative to control lymphocytes, respectively. The Bax/Bcl-2 ratio and caspase-3 activity were higher than the control group (Pv major-treated host lymphocytes dependent on p53 tumor suppressor via mitochondrial pathway may probably address as an auxiliary survival mechanism of L. major in CL patients. However, here is much work ahead to figure out the multiple functions played by apoptosis in the evasion of L. major.

  4. An in silico algorithm for identifying stabilizing pockets in proteins: test case, the Y220C mutant of the p53 tumor suppressor protein.

    Science.gov (United States)

    Bromley, Dennis; Bauer, Matthias R; Fersht, Alan R; Daggett, Valerie

    2016-09-01

    The p53 tumor suppressor protein performs a critical role in stimulating apoptosis and cell cycle arrest in response to oncogenic stress. The function of p53 can be compromised by mutation, leading to increased risk of cancer; approximately 50% of cancers are associated with mutations in the p53 gene, the majority of which are in the core DNA-binding domain. The Y220C mutation of p53, for example, destabilizes the core domain by 4 kcal/mol, leading to rapid denaturation and aggregation. The associated loss of tumor suppressor functionality is associated with approximately 75 000 new cancer cases every year. Destabilized p53 mutants can be 'rescued' and their function restored; binding of a small molecule into a pocket on the surface of mutant p53 can stabilize its wild-type structure and restore its function. Here, we describe an in silico algorithm for identifying potential rescue pockets, including the algorithm's integration with the Dynameomics molecular dynamics data warehouse and the DIVE visual analytics engine. We discuss the results of the application of the method to the Y220C p53 mutant, entailing finding a putative rescue pocket through MD simulations followed by an in silico search for stabilizing ligands that dock into the putative rescue pocket. The top three compounds from this search were tested experimentally and one of them bound in the pocket, as shown by nuclear magnetic resonance, and weakly stabilized the mutant. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  5. Identification and characterisation of Emp53, the homologue of human tumor suppressor p53, from Echinococcus multilocularis: its role in apoptosis and the oxidative stress response.

    Science.gov (United States)

    Cheng, Zhe; Zhu, Shan; Wang, Liang; Liu, Fan; Tian, Huimin; Pengsakul, Theerakamol; Wang, Yanhai

    2015-07-01

    Larvae of the fox tapeworm, Echinococcus multilocularis, cause alveolar echinococcosis, which is considered to be the most lethal helminthic infection in humans. Since it develops in host organs, the parasite must have evolved a stress defense system to cope with various genotoxic and cellular stresses that may cause DNA damage and genomic instability. Tumor suppressor p53, well known as the "guardian of the genome", plays a vital role in response to many types of stress and damage. In the present study, we describe the characterisation of Emp53 from E. multilocularis and demonstrate that it is a structural and functional homologue of mammalian tumor suppressor p53. We show that Emp53 binds specifically to oligonucleotides containing conventional p53 binding sites, indicating that it exhibits a function as a DNA binding transcription factor. Inhibition of Emp53 function can suppress UV irradiation-induced apoptosis in the E. multilocularis metacestode, indicating an important role of Emp53 in the induction of apoptosis following DNA damage. We also reveal that Emp53 plays important roles in resistance to oxidative stress and regulation of oxidative stress-induced apoptosis. Our results suggest that, similar to its human counterpart, Emp53 plays a central role in the network of DNA damage responses and apoptosis in E. multilocularis. These results may help in exploring stress defense mechanisms of parasitic helminths and may provide useful information for the development of new interventions and therapeutic drugs for the control of alveolar echinococcosis. Copyright © 2015 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

  6. Repression of human papillomavirus oncogenes in HeLa cervical carcinoma cells causes the orderly reactivation of dormant tumor suppressor pathways.

    Science.gov (United States)

    Goodwin, E C; DiMaio, D

    2000-11-07

    Most cervical carcinomas express high-risk human papillomaviruses (HPVs) E6 and E7 proteins, which neutralize cellular tumor suppressor function. To determine the consequences of removing the E6 and E7 proteins from cervical cancer cells, we infected HeLa cells, a cervical carcinoma cell line that contains HPV18 DNA, with a recombinant virus that expresses the bovine papillomavirus E2 protein. Expression of the E2 protein resulted in rapid repression of HPV E6 and E7 expression, followed approximately 12 h later by profound inhibition of cellular DNA synthesis. Shortly after E6/E7 repression, there was dramatic posttranscriptional induction of p53. Two p53-responsive genes, mdm2 and p21, were induced with slightly slower kinetics than p53 and appeared to be functional, as assessed by inhibition of cyclin-dependent kinase activity and p53 destabilization. There was also dramatic posttranscriptional induction of p105(Rb) and p107 after E6/E7 repression, followed shortly thereafter by induction of p130. By 24 h after infection, only hypophosphorylated p105(Rb) was detectable and transcription of several Rb/E2F-regulated genes was dramatically repressed. Constitutive expression of the HPV16 E6/E7 genes alleviated E2-induced growth inhibition and impaired activation of the Rb pathway and repression of E2F-responsive genes. This dynamic response strongly suggests that the p53 and Rb tumor suppressor pathways are intact in HeLa cells and that repression of HPV E6 and E7 mobilizes these pathways in an orderly fashion to deliver growth inhibitory signals to the cells. Strikingly, the major alterations in the cell cycle machinery underlying cervical carcinogenesis can be reversed by repression of the endogenous HPV oncogenes.

  7. KISS1 tumor suppressor restricts angiogenesis of breast cancer brain metastases and sensitizes them to oncolytic virotherapy in vitro.

    Science.gov (United States)

    Platonov, Mikhail E; Borovjagin, Anton V; Kaverina, Natalya; Xiao, Ting; Kadagidze, Zaira; Lesniak, Maciej; Baryshnikova, Marya; Ulasov, Ilya V

    2018-03-28

    KISS1 tumor suppressor protein regulates cancer cell invasion via MMP9 metalloproteinase. Downregulation of KISS1 gene expression promotes progression of breast cancer and melanoma, resulting in the development of distant metastases. In the current study, we investigated whether restoration of KISS1 expression in KISS1-deficient human metastatic breast cancer cells holds potential as an advanced anticancer strategy. To this end we engineered an infectivity-enhanced conditionally-replicative human adenovirus type 5 encoding KISS1 as an "arming" transgene in the Ad5 E3 region for an ectopic KISS1 expression in transduced cancer cells. The oncolytic potential of the vector was examined using brain-invading metastatic clones of CN34 and MDA-MB-231 breast cancer cells, which supported high levels of AdKISS1 replication, correlating with a robust CRAd-mediated cytotoxicity. Secretion of cellular factors responsible for tumor angiogenesis, cell-to-cell communication and anti-tumoral immune responses upon KISS1 expression in breast cancer cells was analyzed by a RayBiotech Kiloplex Quantibody array. Overall, our results indicate that KISS1 transgene expression provides an important benefit for CRAd-mediated cytotoxicity in breast cancer cells and holds potential as an anticancer treatment in conjunction with oncolytic virotherapy of breast and other metastatic cancers. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Semaphorin7A promotes tumor growth and exerts a pro-angiogenic effect in macrophages of mammary tumor-bearing mice

    Directory of Open Access Journals (Sweden)

    Ramon eGarcia-Areas

    2014-02-01

    Full Text Available Semaphorins, a large family of molecules involved in the axonal guidance and development of the nervous system, have been recently shown to have both angiogenic and anti-angiogenic properties. Specifically, semaphorin 7A (SEMA7A has been reported to have a chemotactic activity in neurogenesis, and to be an immune modulator via it binding to α1β1integrins. Additionally, SEMA7A has been shown to promote chemotaxis of monocytes, inducing them to produce proinflammatory mediators. In this study we explored the role of SEMA7A in the tumoral context. We show that SEMA7A is highly expressed by DA-3 murine mammary tumor cells in comparison to normal mammary cells (EpH4, and that peritoneal macrophages from mammary tumor-bearing mice also express SEMA7A at higher levels compared to peritoneal macrophages derived from normal control mice. We also show that murine macrophages treated with recombinant murine SEMA7A significantly increased their expression of proangiogenic molecules, such as CXCL2/MIP-2. Gene silencing of SEMA7A in peritoneal elicited macrophages from DA-3 tumor-bearing mice resulted in decreased CXCL2 expression. Mice implanted with SEMA7A silenced tumor cells showed decreased angiogenesis in the tumors compared to the wild type tumors. Furthermore, peritoneal elicited macrophages from mice bearing SEMA7A-silenced tumors produce significantly (p< 0.01 lower levels of angiogenic proteins, such as MIP-2, CXCL1 and MMP-9, compared to macrophages from control DA-3 mammary tumors. We postulate that SEMA7A derived from mammary carcinomas may serve as a monocyte chemoattractant and skew monocytes into a pro-tumorigenic phenotype. A putative relationship between tumor-derived SEMA7A and monocytes could prove valuable in establishing new research avenues towards unraveling important tumor-host immune interactions in breast cancer patients.

  9. Alpha-momorcharin (α-MMC) exerts effective anti-human breast tumor activities but has a narrow therapeutic window in vivo.

    Science.gov (United States)

    Cao, Dongliang; Sun, Yun; Wang, Ling; He, Qianchuan; Zheng, Juecun; Deng, Fei; Deng, Shanshan; Chang, ShuChing; Yu, XiaoPing; Li, Minhui; Meng, Yao; Jin, Jiagui; Shen, Fubing

    2015-01-01

    Alpha-momorcharin (α-MMC), a ribosome inactivating protein (RIP) extracted from the seeds of Momordica charantia, exerts anti-tumor, antiviral, and anti-fungal activities. However, α-MMC has an obvious toxicity that limits its clinical application. We examined the effect of α-MMC on the inhibition of human breast cancer and assessed its general toxicity to find the therapeutic window in vivo for its potential clinical use. It was purified using column chromatography, and then injected into the xenograft nude mouse model induced by MDA-MB-231 and MCF-7. The anti-tumor efficacy was evaluated with T/C%. Next, the α-MMC was injected at a series of doses to Balb/C mice to assess its general toxicity. The MTT assay, the apoptosis test, and the cell cycle inhibition of α-MMC in human breast cancer cells were performed. In the xenografted tumors induced by MDA-MB-231 and MCF-7, α-MMC exerted an obvious inhibition effects on tumor growth at the dosage of 1.2mg/kg and 0.8 mg/kg. For in vivo toxicity experiments of α-MMC in Balb/C mice, the minimal toxic dose of α-MMC was 1.2mg/kg. Alpha-MMC induced apoptosis by increasing caspase3 activities, and the cell cycle was arrested at the G0/G1 or G2/M phases. The measurements of IC50 were 15.07 μg/mL, 33.66 μg/mL, 42.94 μg/mL for MDA-MB-231, MCF-7 and MDA-MB-453 respectively. Alpha-MMC exhibits anti-tumor effects in human breast cancer in vivo and in vitro. It inhibits breast cancer cells through the inhibition of tumor growth and induction of cell apoptosis. However, due to its obvious toxicity, α-MMC has a relatively narrow therapeutic window in vivo. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. EZH2-Regulated DAB2IP Is a Medulloblastoma Tumor Suppressor and a Positive Marker for Survival

    NARCIS (Netherlands)

    Smits, Michiel; van Rijn, Sjoerd; Hulleman, Esther; Biesmans, Dennis; van Vuurden, Dannis G.; Kool, Marcel; Haberler, Christine; Aronica, Eleonora; Vandertop, W. Peter; Noske, David P.; Würdinger, Thomas

    2012-01-01

    Purpose: Medulloblastoma is the most common malignant brain tumor in children. Despite recent improvements, the molecular mechanisms driving medulloblastoma are not fully understood and further elucidation could provide cues to improve outcome prediction and therapeutic approaches. Experimental

  11. HDAC inhibitor L-carnitine and proteasome inhibitor bortezomib synergistically exert anti-tumor activity in vitro and in vivo.

    Directory of Open Access Journals (Sweden)

    Hongbiao Huang

    Full Text Available Combinations of proteasome inhibitors and histone deacetylases (HDAC inhibitors appear to be the most potent to produce synergistic cytotoxicity in preclinical trials. We have recently confirmed that L-carnitine (LC is an endogenous HDAC inhibitor. In the current study, the anti-tumor effect of LC plus proteasome inhibitor bortezomib (velcade, Vel was investigated both in cultured hepatoma cancer cells and in Balb/c mice bearing HepG2 tumor. Cell death and cell viability were assayed by flow cytometry and MTS, respectively. Gene, mRNA expression and protein levels were detected by gene microarray, quantitative real-time PCR and Western blot, respectively. The effect of Vel on the acetylation of histone H3 associated with the p21(cip1 gene promoter was examined by using ChIP assay and proteasome peptidase activity was detected by cell-based chymotrypsin-like (CT-like activity assay. Here we report that (i the combination of LC and Vel synergistically induces cytotoxicity in vitro; (ii the combination also synergistically inhibits tumor growth in vivo; (iii two major pathways are involved in the synergistical effects of the combinational treatment: increased p21(cip1 expression and histone acetylation in vitro and in vivo and enhanced Vel-induced proteasome inhibition by LC. The synergistic effect of LC and Vel in cancer therapy should have great potential in the future clinical trials.

  12. MDA-7/IL-24 functions as a tumor suppressor gene in vivo in transgenic mouse models of breast cancer.

    Science.gov (United States)

    Menezes, Mitchell E; Shen, Xue-Ning; Das, Swadesh K; Emdad, Luni; Guo, Chunqing; Yuan, Fang; Li, You-Jun; Archer, Michael C; Zacksenhaus, Eldad; Windle, Jolene J; Subler, Mark A; Ben-David, Yaacov; Sarkar, Devanand; Wang, Xiang-Yang; Fisher, Paul B

    2015-11-10

    Melanoma differentiation associated gene-7/Interleukin-24 (MDA-7/IL-24) is a novel member of the IL-10 gene family that selectively induces apoptosis and toxic autophagy in a broad spectrum of human cancers, including breast cancer, without harming normal cells or tissues. The ability to investigate the critical events underlying cancer initiation and progression, as well as the capacity to test the efficacy of novel therapeutics, has been significantly advanced by the development of genetically engineered mice (GEMs) that accurately recapitulate specific human cancers. We utilized three transgenic mouse models to better comprehend the in vivo role of MDA-7/IL-24 in breast cancer. Using the MMTV-PyMT spontaneous mammary tumor model, we confirmed that exogenously introducing MDA-7/IL-24 using a Cancer Terminator Virus caused a reduction in tumor burden and also produced an antitumor "bystander" effect. Next we performed xenograft studies in a newly created MMTV-MDA-7 transgenic model that over-expresses MDA-7/IL-24 in the mammary glands during pregnancy and lactation, and found that MDA-7/IL-24 overexpression delayed tumor growth following orthotopic injection of a murine PDX tumor cell line (mPDX) derived from a tumor formed in an MMTV-PyMT mouse. We also crossed the MMTV-MDA-7 line to MMTV-Erbb2 transgenic mice and found that MDA-7/IL-24 overexpression delayed the onset of mammary tumor development in this model of spontaneous mammary tumorigenesis as well. Finally, we assessed the role of MDA-7/IL-24 in immune regulation, which can potentially contribute to tumor suppression in vivo. Our findings provide further direct in vivo evidence for the role of MDA-7/IL-24 in tumor suppression in breast cancer in immune-competent transgenic mice.

  13. miR-32 functions as a tumor suppressor and directly targets SOX9 in human non-small cell lung cancer.

    Science.gov (United States)

    Zhu, Dan; Chen, Hui; Yang, Xiguang; Chen, Weisong; Wang, Linying; Xu, Jilin; Yu, Long

    2015-01-01

    MicroRNA-32 (miR-32) is dysregulated in certain human malignancies and correlates with tumor progression. However, its expression and function in non-small cell lung cancer (NSCLC) remain unclear. Thus, the aim of this study was to explore the effects of miR-32 expression on NSCLC tumorigenesis and development. Using real-time quantitative reverse-transcription polymerase chain reaction (qRT-PCR), we detected miR-32 expression in NSCLC cell lines and primary tumor tissues. The association of miR-32 expression with clinicopathological factors and prognosis was also analyzed. Then, the effects of miR-32 expression on the biological behavior of NSCLC cells were investigated. Finally, the potential regulatory effect of miR-32 on SOX9 expression was confirmed. miR-32 expression levels were significantly downregulated in NSCLC compared with the corresponding noncancerous lung tissues (P32 expression was significantly associated with lymph node metastasis (P=0.002), advanced tumor/nodes/metastasis (TNM) classification stages (P32 expression was an independent unfavorable prognostic factor for NSCLC patients. In vitro studies demonstrated that miR-32 overexpression reduced A549 cell proliferation, migration, and invasion, and promoted apoptosis. Furthermore, SOX9 was confirmed as a direct target of miR-32, using a luciferase reporter assay. These findings indicate that miR-32 may act as a tumor suppressor in NSCLC and could serve as a novel therapeutic agent for miR-based therapy.

  14. ASS1 as a novel tumor suppressor gene in myxofibrosarcomas: aberrant loss via epigenetic DNA methylation confers aggressive phenotypes, negative prognostic impact, and therapeutic relevance.

    Science.gov (United States)

    Huang, Hsuan-Ying; Wu, Wen-Ren; Wang, Yu-Hui; Wang, Jun-Wen; Fang, Fu-Min; Tsai, Jen-Wei; Li, Shau-Hsuan; Hung, Hsiao-Chin; Yu, Shih-Chen; Lan, Jui; Shiue, Yow-Ling; Hsing, Chung-His; Chen, Li-Tzong; Li, Chien-Feng

    2013-06-01

    The principal goals were to identify and validate targetable metabolic drivers relevant to myxofibrosarcoma pathogenesis using a published transcriptome. As the most significantly downregulated gene regulating amino acid metabolism, argininosuccinate synthetase (ASS1) was selected for further analysis by methylation-specific PCR, pyrosequencing, and immunohistochemistry of myxofibrosarcoma samples. The roles of ASS1 in tumorigenesis and the therapeutic relevance of the arginine-depriving agent pegylated arginine deiminase (ADI-PEG20) were elucidated in ASS1-deficient myxofibrosarcoma cell lines and xenografts with and without stable ASS1 reexpression. ASS1 promoter hypermethylation was detected in myxofibrosarcoma samples and cell lines and was strongly linked to ASS1 protein deficiency. The latter correlated with increased tumor grade and stage and independently predicted a worse survival. ASS1-deficient cell lines were auxotrophic for arginine and susceptible to ADI-PEG20 treatment, with dose-dependent reductions in cell viability and tumor growth attributable to cell-cycle arrest in the S-phase. ASS1 expression was restored in 2 of 3 ASS1-deficient myxofibrosarcoma cell lines by 5-aza-2'-deoxycytidine, abrogating the inhibitory effect of ADI-PEG20. Conditioned media following ASS1 reexpression attenuated HUVEC tube-forming capability, which was associated with suppression of MMP-9 and an antiangiogenic effect in corresponding myxofibrosarcoma xenografts. In addition to delayed wound closure and fewer invading cells in a Matrigel assay, ASS1 reexpression reduced tumor cell proliferation, induced G1-phase arrest, and downregulated cyclin E with corresponding growth inhibition in soft agar and xenograft assays. Our findings highlight ASS1 as a novel tumor suppressor in myxofibrosarcomas, with loss of expression linked to promoter methylation, clinical aggressiveness, and sensitivity to ADI-PEG20. ©2013 AACR

  15. The putative tumor suppressor microRNA-497 modulates gastric cancer cell proliferation and invasion by repressing eIF4E

    Energy Technology Data Exchange (ETDEWEB)

    Li, Weidong; Jin, Xuejun; Deng, Xubin [Department of Medical Oncology, Affiliated Cancer Hospital of Guangzhou Medical University, Cancer Center of Guangzhou Medical University (CCGMU), Guangzhou (China); Zhang, Gong [Department of Radiotherapy, People’s Hospital of Shanxi Province, Taiyuan (China); Zhang, Bingqian [Cancer Research Institution, Southern Medical University, Guangzhou (China); Ma, Lei, E-mail: malei01@yeah.net [Department of Medical Oncology, Affiliated Cancer Hospital of Guangzhou Medical University, Cancer Center of Guangzhou Medical University (CCGMU), Guangzhou (China)

    2014-06-27

    Highlights: • MiR-497 expression was down-regulated in GC patients and GC cell lines. • MiR-497 inhibited cell proliferation and invasion of GC cells in vitro. • MiR-497 modulated eIF4E expression in GC cells. • Restoration of miR-497 decreased tumor growth and metastasis in vivo. - Abstract: Accumulating evidence has shown that microRNAs are involved in multiple processes in gastric cancer (GC) development and progression. Aberrant expression of miR-497 has been frequently reported in cancer studies; however, the role and mechanism of its function in GC remains unknown. Here, we reported that miR-497 was frequently downregulated in GC tissues and associated with aggressive clinicopathological features of GC patients. Further in vitro observations showed that the enforced expression of miR-497 inhibited cell proliferation by blocking the G1/S transition and decreased the invasion of GC cells, implying that miR-497 functions as a tumor suppressor in the progression of GC. In vivo study indicated that restoration of miR-497 inhibited tumor growth and metastasis. Luciferase assays revealed that miR-497 inhibited eIF4E expression by targeting the binding sites in the 3′-untranslated region of eIF4E mRNA. qRT-PCR and Western blot assays verified that miR-497 reduced eIF4E expression at both the mRNA and protein levels. A reverse correlation between miR-497 and eIF4E expression was noted in GC tissues. Taken together, our results identify a crucial tumor suppressive role of miR-497 in the progression of GC and suggest that miR-497 might be an anticancer therapeutic target for GC patients.

  16. Tumor suppressor gene mutation in a patient with a history of hyperparathyroidism-jaw tumor syndrome and healed generalized osteitis fibrosa cystica: a case report and genetic pathophysiology review.

    Science.gov (United States)

    Parfitt, Joshua; Harris, Malcolm; Wright, John M; Kalamchi, Sabah

    2015-01-01

    Hyperparathyroidism-jaw tumor (HPT-JT) was first observed by Jackson in 1958 in a family who exhibited hyperparathyroidism and recurrent pancreatitis. The author noticed the presence of jaw tumors in the affected family and reported them as fibrous dysplasia. However, it was not until 1990 that a familial variety of hyperparathyroidism with fibro-osseous jaw tumors was recognized as HPT-JT syndrome and reported as a clinically and genetically distinct syndrome. Hyperparathyroidism generally arises from glandular hyperplasia or parathyroid adenomas, with only about 1% of cases resulting from parathyroid carcinoma. However, parathyroid carcinoma develops in about 15% of HPT-JT patients. The true incidence of HPT-JT is unknown, although the prevalence of about 100 published cases suggests its rarity. Twenty percent of HPT-JT cases have renal hamartomas or tumors, and female patients with HPT-JT have been reported to have carcinoma of the uterus. This syndrome appears to arise from a variety of mutations that deactivate the tumor suppressor gene CDC73 (also known as HRPT2) and its production of the tumor suppressor protein parafibromin. Functional parafibromin has 531 amino acids, and mutations result in a short nonfunctional protein. CDC73 disorders exhibit dominant germline gene behavior, with varying degrees of penetration. In most cases an affected person has 1 parent with the condition, which raises the need for family investigation and genetic counseling. We report a case of HPT-JT syndrome in a male patient who presented to the local community hospital 6 years previously with a history of back pain. Investigations showed elevated serum parathyroid hormone and calcium levels, and a technetium 99m sestamibi parathyroid scan showed increased activity at the site of the lower left gland that proved to be a substernal parathyroid carcinoma. The patient's parathyroid hormone level dropped from 126 to 97 pg/mL at 5 minutes and was 65 pg/mL at 10 minutes after excision

  17. Epigenetic silencing of the NR4A3 tumor suppressor, by aberrant JAK/STAT signaling, predicts prognosis in gastric cancer

    Science.gov (United States)

    Yeh, Chung-Min; Chang, Liang-Yu; Lin, Shu-Hui; Chou, Jian-Liang; Hsieh, Hsiao-Yen; Zeng, Li-Han; Chuang, Sheng-Yu; Wang, Hsiao-Wen; Dittner, Claudia; Lin, Cheng-Yu; Lin, Jora M. J.; Huang, Yao-Ting; Ng, Enders K. W.; Cheng, Alfred S. L.; Wu, Shu-Fen; Lin, Jiayuh; Yeh, Kun-Tu; Chan, Michael W. Y.

    2016-08-01

    While aberrant JAK/STAT signaling is crucial to the development of gastric cancer (GC), its effects on epigenetic alterations of its transcriptional targets remains unclear. In this study, by expression microarrays coupled with bioinformatic analyses, we identified a putative STAT3 target gene, NR4A3 that was downregulated in MKN28 GC daughter cells overexpressing a constitutively activated STAT3 mutant (S16), as compared to an empty vector control (C9). Bisulphite pyrosequencing and demethylation treatment showed that NR4A3 was epigenetically silenced by promoter DNA methylation in S16 and other GC cell lines including AGS cells, showing constitutive activation of STAT3. Subsequent experiments revealed that NR4A3 promoter binding by STAT3 might repress its transcription. Long-term depletion of STAT3 derepressed NR4A3 expression, by promoter demethylation, in AGS GC cells. NR4A3 re-expression in GC cell lines sensitized the cells to cisplatin, and inhibited tumor growth in vitro and in vivo, in an animal model. Clinically, GC patients with high NR4A3 methylation, or lower NR4A3 protein expression, had significantly shorter overall survival. Intriguingly, STAT3 activation significantly associated only with NR4A3 methylation in low-stage patient samples. Taken together, aberrant JAK/STAT3 signaling epigenetically silences a potential tumor suppressor, NR4A3, in gastric cancer, plausibly representing a reliable biomarker for gastric cancer prognosis.

  18. Cisplatin and photodynamic therapy exert synergistic inhibitory effects on small-cell lung cancer cell viability and xenograft tumor growth.

    Science.gov (United States)

    Cheng, You-Shuang; Peng, Yin-Bo; Yao, Min; Teng, Ji-Ping; Ni, Da; Zhu, Zhi-Jun; Zhuang, Bu-Feng; Yang, Zhi-Yin

    2017-06-03

    Lung cancer is the leading cause of cancer death worldwide. Small-cell lung cancer (SCLC) is an aggressive type of lung cancer that shows an overall 5-year survival rate below 10%. Although chemotherapy using cisplatin has been proven effective in SCLC treatment, conventional dose of cisplatin causes adverse side effects. Photodynamic therapy, a form of non-ionizing radiation therapy, is increasingly used alone or in combination with other therapeutics in cancer treatment. Herein, we aimed to address whether low dose cisplatin combination with PDT can effectively induce SCLC cell death by using in vitro cultured human SCLC NCI-H446 cells and in vivo tumor xenograft model. We found that both cisplatin and PDT showed dose-dependent cytotoxic effects in NCI-H446 cells. Importantly, co-treatment with low dose cisplatin (1 μM) and PDT (1.25 J/cm2) synergistically inhibited cell viability and cell migration. We further showed that the combined therapy induced a higher level of intracellular ROS in cultured NCI-H446 cells. Moreover, the synergistic effect by cisplatin and PDT was recapitulated in tumor xenograft as revealed by a more robust increase in the staining of TUNEL (a marker of cell death) and decrease in tumor volume. Taken together, our findings suggest that low dose cisplatin combination with PDT can be an effective therapeutic modality in the treatment of SCLC patients. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Autotaxin and LPA1 and LPA5 receptors exert disparate functions in tumor cells versus the host tissue microenvironment in melanoma invasion and metastasis.

    Science.gov (United States)

    Lee, Sue-Chin; Fujiwara, Yuko; Liu, Jianxiong; Yue, Junming; Shimizu, Yoshibumi; Norman, Derek D; Wang, Yaohong; Tsukahara, Ryoko; Szabo, Erzsebet; Patil, Renukadevi; Banerjee, Souvik; Miller, Duane D; Balazs, Louisa; Ghosh, Manik C; Waters, Christopher M; Oravecz, Tamas; Tigyi, Gabor J

    2015-01-01

    Autotaxin (ENPP2/ATX) and lysophosphatidic acid (LPA) receptors represent two key players in regulating cancer progression. The present study sought to understand the mechanistic role of LPA G protein-coupled receptors (GPCR), not only in the tumor cells but also in stromal cells of the tumor microenvironment. B16F10 melanoma cells predominantly express LPA5 and LPA2 receptors but lack LPA1. LPA dose dependently inhibited invasion of cells across a Matrigel layer. RNAi-mediated knockdown of LPA5 relieved the inhibitory effect of LPA on invasion without affecting basal invasion. This suggests that LPA5 exerts an anti-invasive action in melanoma cells in response to LPA. In addition, both siRNA-mediated knockdown and pharmacologic inhibition of LPA2 reduced the basal rate invasion. Unexpectedly, when probing the role of this GPCR in host tissues, it was found that the incidence of melanoma-derived lung metastasis was greatly reduced in LPA5 knockout (KO) mice compared with wild-type (WT) mice. LPA1-KO but not LPA2-KO mice also showed diminished melanoma-derived lung metastasis, suggesting that host LPA1 and LPA5 receptors play critical roles in the seeding of metastasis. The decrease in tumor cell residence in the lungs of LPA1-KO and LPA5-KO animals was apparent 24 hours after injection. However, KO of LPA1, LPA2, or LPA5 did not affect the subcutaneous growth of melanoma tumors. These findings suggest that tumor and stromal LPA receptors, in particular LPA1 and LPA5, play different roles in invasion and the seeding of metastasis. ©2014 American Association for Cancer Research.

  20. NLRX1 Acts as an Epithelial-Intrinsic Tumor Suppressor through the Modulation of TNF-Mediated Proliferation

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    Ivan Tattoli

    2016-03-01

    Full Text Available The mitochondrial Nod-like receptor protein NLRX1 protects against colorectal tumorigenesis through mechanisms that remain unclear. Using mice with an intestinal epithelial cells (IEC-specific deletion of Nlrx1, we find that NLRX1 provides an IEC-intrinsic protection against colitis-associated carcinogenesis in the colon. These Nlrx1 mutant mice have increased expression of Tnf, Egf, and Tgfb1, three factors essential for wound healing, as well as increased epithelial proliferation during the epithelial regeneration phase following injury triggered by dextran sodium sulfate. In primary intestinal organoids lacking Nlrx1, stimulation with TNF resulted in exacerbated proliferation and expression of the intestinal stem cell markers Olfm4 and Myb. This hyper-proliferation response was associated with increased activation of Akt and NF-κB pathways in response to TNF stimulation. Together, these results identify NLRX1 as a suppressor of colonic tumorigenesis that acts by controlling epithelial proliferation in the intestine during the regeneration phase following mucosal injury.

  1. Oxidized LDL induces an oxidative stress and activates the tumor suppressor p53 in MRC5 human fibroblasts.

    Science.gov (United States)

    Mazière, C; Meignotte, A; Dantin, F; Conte, M A; Mazière, J C

    2000-09-24

    It is now well established that oxidized LDL (OxLDL) is involved in the progression of the atheromatous plaque via several mechanisms, including its cytotoxicity toward the arterial wall. Our study demonstrates that a 4-h incubation of cultured human fibroblasts with 25-75 microg/ml OxLDL induced a dose-dependent increase in the intracellular levels of reactive oxygen species (ROS) and lipid peroxidation end products (TBARS). This effect was markedly prevented by the antioxidant vitamin E. The lipid extract of OxLDL partially reproduced the action of the LDL particle itself. Concomitantly, OxLDL enhanced the DNA binding activity of p53 measured by electrophoretic mobility shift assay, and the intracellular protein level of p53 determined by immunoblot analysis. Cycloheximide prevented the OxLDL-induced augmentation in both p53 binding activity and intracellular level. Again, the lipid extract of OxLDL reproduced the effect of OxLDL on p53 binding activity, whereas vitamin E prevented it. These results indicate that OxLDL initiates an intracellular oxidative stress by means of its lipid peroxidation products, leading to the activation of the tumour suppressor p53 by enhancement of p53 protein synthesis. This effect might be related to the cytotoxic effect of OxLDL since the activation of p53 is known to lead to cell cycle arrest, necrosis or apoptosis. Copyright 2000 Academic Press.

  2. The humanized anti-human AMHRII mAb 3C23K exerts an anti-tumor activity against human ovarian cancer through tumor-associated macrophages.

    Science.gov (United States)

    Bougherara, Houcine; Némati, Fariba; Nicolas, André; Massonnet, Gérald; Pugnière, Martine; Ngô, Charlotte; Le Frère-Belda, Marie-Aude; Leary, Alexandra; Alexandre, Jérôme; Meseure, Didier; Barret, Jean-Marc; Navarro-Teulon, Isabelle; Pèlegrin, André; Roman-Roman, Sergio; Prost, Jean-François; Donnadieu, Emmanuel; Decaudin, Didier

    2017-11-21

    Müllerian inhibiting substance, also called anti-Müllerian hormone (AMH), inhibits proliferation and induces apoptosis of AMH type II receptor-positive tumor cells, such as human ovarian cancers (OCs). On this basis, a humanized glyco-engineered monoclonal antibody (3C23K) has been developed. The aim of this study was therefore to experimentally confirm the therapeutic potential of 3C23K in human OCs. We first determined by immunofluorescence, immunohistochemistry and cytofluorometry analyses the expression of AMHRII in patient's tumors and found that a majority (60 to 80% depending on the detection technique) of OCs were positive for this marker. We then provided evidence that the tumor stroma of OC is enriched in tumor-associated macrophages and that these cells are responsible for 3C23K-induced killing of tumor cells through ADCP and ADCC mechanisms. In addition, we showed that 3C23K reduced macrophages induced-T cells immunosuppression. Finally, we evaluated the therapeutic efficacy of 3C23K alone and in combination with a carboplatin-paclitaxel chemotherapy in a panel of OC Patient-Derived Xenografts. In those experiments, we showed that 3C23K significantly increased the proportion and the quality of chemotherapy-based in vivo responses. Altogether, our data support the potential interest of AMHRII targeting in human ovarian cancers and the evaluation of 3C23K in further clinical trials.

  3. Differences in expression of oncogenes and tumor suppressor genes in different sites of head and neck squamous cell

    NARCIS (Netherlands)

    Takes, R P; Baatenburg de Jong, R J; Schuuring, E; Litvinov, S V; Hermans, J; Van Krieken, J H

    1999-01-01

    BACKGROUND: In most studies concerning chromosomal changes or protein expression in head and neck squamous cell carcinomas (HNSCC) no distinction is made between the sites within this area. The behaviour of tumors arising in one site or the other, however, differs significantly, suggesting different

  4. The soybean peptide lunasin promotes apoptosis of mammary epithelial cells via induction of tumor suppressor PTEN: similarities and distinct actions from soy isoflavone genistein.

    Science.gov (United States)

    Pabona, John Mark P; Dave, Bhuvanesh; Su, Ying; Montales, Maria Theresa E; de Lumen, Ben O; de Mejia, Elvira G; Rahal, Omar M; Simmen, Rosalia C M

    2013-01-01

    Breast cancer is the leading cause of cancer deaths in women. Diet and lifestyle are major contributing factors to increased breast cancer risk. While mechanisms underlying dietary protection of mammary tumor formation are increasingly elucidated, there remains a dearth of knowledge on the nature and precise actions of specific bioactive components present in foods with purported health effects. The 43-amino acid peptide lunasin (LUN) is found in soybeans, is bioavailable similar to the isoflavone genistein (GEN), and thus may mediate the beneficial effects of soy food consumption. Here, we evaluated whether LUN displays common and distinct actions from those of GEN in non-malignant (mouse HC11) and malignant (human MCF-7) mammary epithelial cells. In MCF-7 cells, LUN up-regulated tumor suppressor phosphatase and tensin homolog deleted in chromosome ten (PTEN) promoter activity, increased PTEN transcript and protein levels and enhanced nuclear PTEN localization, similar to that shown for GEN in mammary epithelial cells. LUN-induced cellular apoptosis, akin to GEN, was mediated by PTEN, but unlike that for GEN, was p53-independent. LUN promoted E-cadherin and β-catenin non-nuclear localization similar to GEN, but unlike GEN, did not influence the proliferative effects of oncogene Wnt1 on HC11 cells. Further, LUN did not recapitulate GEN inhibitory effects on expansion of the cancer stem-like/progenitor population in MCF-7 cells. Results suggest the concerted actions of GEN and LUN on cellular apoptosis for potential mammary tumor preventive effects and highlight whole food consumption rather than intake of specific dietary supplements with limited biological effects for greater health benefits.

  5. Re-expression of methylation-induced tumor suppressor gene silencing is associated with the state of histone modification in gastric cancer cell lines.

    Science.gov (United States)

    Meng, Chun-Feng; Zhu, Xin-Jiang; Peng, Guo; Dai, Dong-Qiu

    2007-12-14

    To identify the relationship between DNA hyper-methylation and histone modification at a hyperme-thylated, silenced tumor suppressor gene promoter in human gastric cancer cell lines and to elucidate whether alteration of DNA methylation could affect histone modification. We used chromatin immunoprecipitation (ChIP) assay to assess the status of histone acetylation and methylation in promoter regions of the p16 and mutL homolog 1 (MLH1) genes in 2 gastric cancer cell lines, SGC-7901 and MGC-803. We used methylation-specific PCR (MSP) to evaluate the effect of 5-Aza-2'-deoxycytidine (5-Aza-dC), trichostatin A (TSA) or their combination treatment on DNA methylation status. We used RT-PCR to determine whether alterations of histone modification status after 5-Aza-dC and TSA treatment are reflected in gene expression. For the p16 and MLH1 genes in two cell lines, silenced loci associated with DNA hypermethylation were characterized by histone H3-K9 hypoacetylation and hypermethylation and histone H3-K4 hypomethylation. Treatment with TSA resulted in moderately increased histone H3-K9 acetylation at the silenced loci with no effect on histone H3-K9 methylation and minimal effects on gene expression. In contrast, treatment with 5-Aza-dC rapidly reduced histone H3-K9 methylation at the silenced loci and resulted in reactivation of the two genes. Combined treatment with 5-Aza-dC and TSA was synergistic in reactivating gene expression at the loci showing DNA hypermethylation. Similarly, histone H3-K4 methylation was not affected after TSA treatment, and increased moderately at the silenced loci after 5-Aza-dC treatment. Hypermethylation of DNA in promoter CpG islands is related to transcriptional silencing of tumor suppressor genes. Histone H3-K9 methylation in different regions of the promoters studied correlates with DNA methylation status of each gene in gastric cancer cells. However, histone H3-K9 acetylation and H3-K4 methylation inversely correlate with DNA methylation

  6. Involvement of PSMD10, CDK4, and Tumor Suppressors in Development of Intrahepatic Cholangiocarcinoma of Syrian Golden Hamsters Induced by Clonorchis sinensis and N-Nitrosodimethylamine.

    Science.gov (United States)

    Uddin, Md Hafiz; Choi, Min-Ho; Kim, Woo Ho; Jang, Ja-June; Hong, Sung-Tae

    2015-01-01

    Clonorchis sinensis is a group-I bio-carcinogen for cholangiocarcinoma (CCA). Although the epidemiological evidence links clonorchiasis and CCA, the underlying molecular mechanism involved in this process is poorly understood. In the present study, we investigated expression of oncogenes and tumor suppressors, including PSMD10, CDK4, p53 and RB in C. sinensis induced hamster CCA model. Different histochemical/immunohistochemical techniques were performed to detect CCA in 4 groups of hamsters: uninfected control (Ctrl.), infected with C. sinensis (Cs), ingested N-nitrosodimethylamine (NDMA), and both Cs infected and NDMA introduced (Cs+NDMA). The liver tissues from all groups were analyzed for gene/protein expressions by quantitative PCR (qPCR) and western blotting. CCA was observed in all hamsters of Cs+NDMA group with well, moderate, and poorly differentiated types measured in 21.8% ± 1.5%, 13.3% ± 1.3%, and 10.8% ± 1.3% of total tissue section areas respectively. All CCA differentiations progressed in a time dependent manner, starting from the 8th week of infection. CCA stroma was characterized with increased collagen type I, mucin, and proliferative cell nuclear antigen (PCNA). The qPCR analysis showed PSMD10, CDK4 and p16INK4 were over-expressed, whereas p53 was under-expressed in the Cs+NDMA group. We observed no change in RB1 at mRNA level but found significant down-regulation of RB protein. The apoptosis related genes, BAX and caspase 9 were found downregulated in the CCA tissue. Gene/protein expressions were matched well with the pathological changes of different groups except the NDMA group. Though the hamsters in the NDMA group showed no marked pathological lesions, we observed over-expression of Akt/PKB and p53 genes proposing molecular interplay in this group which might be related to the CCA initiation in this animal model. The present findings suggest that oncogenes, PSMD10 and CDK4, and tumor suppressors, p53 and RB, are involved in the

  7. Involvement of PSMD10, CDK4, and Tumor Suppressors in Development of Intrahepatic Cholangiocarcinoma of Syrian Golden Hamsters Induced by Clonorchis sinensis and N-Nitrosodimethylamine.

    Directory of Open Access Journals (Sweden)

    Md Hafiz Uddin

    Full Text Available Clonorchis sinensis is a group-I bio-carcinogen for cholangiocarcinoma (CCA. Although the epidemiological evidence links clonorchiasis and CCA, the underlying molecular mechanism involved in this process is poorly understood. In the present study, we investigated expression of oncogenes and tumor suppressors, including PSMD10, CDK4, p53 and RB in C. sinensis induced hamster CCA model.Different histochemical/immunohistochemical techniques were performed to detect CCA in 4 groups of hamsters: uninfected control (Ctrl., infected with C. sinensis (Cs, ingested N-nitrosodimethylamine (NDMA, and both Cs infected and NDMA introduced (Cs+NDMA. The liver tissues from all groups were analyzed for gene/protein expressions by quantitative PCR (qPCR and western blotting.CCA was observed in all hamsters of Cs+NDMA group with well, moderate, and poorly differentiated types measured in 21.8% ± 1.5%, 13.3% ± 1.3%, and 10.8% ± 1.3% of total tissue section areas respectively. All CCA differentiations progressed in a time dependent manner, starting from the 8th week of infection. CCA stroma was characterized with increased collagen type I, mucin, and proliferative cell nuclear antigen (PCNA. The qPCR analysis showed PSMD10, CDK4 and p16INK4 were over-expressed, whereas p53 was under-expressed in the Cs+NDMA group. We observed no change in RB1 at mRNA level but found significant down-regulation of RB protein. The apoptosis related genes, BAX and caspase 9 were found downregulated in the CCA tissue. Gene/protein expressions were matched well with the pathological changes of different groups except the NDMA group. Though the hamsters in the NDMA group showed no marked pathological lesions, we observed over-expression of Akt/PKB and p53 genes proposing molecular interplay in this group which might be related to the CCA initiation in this animal model.The present findings suggest that oncogenes, PSMD10 and CDK4, and tumor suppressors, p53 and RB, are involved in the

  8. Tumor suppressor PTEN affects tau phosphorylation: deficiency in the phosphatase activity of PTEN increases aggregation of an FTDP-17 mutant Tau

    Directory of Open Access Journals (Sweden)

    Zhang Xue

    2006-07-01

    Full Text Available Abstract Background Aberrant hyperphosphorylation of tau protein has been implicated in a variety of neurodegenerative disorders. Although a number of protein kinases have been shown to phosphorylate tau in vitro and in vivo, the molecular mechanisms by which tau phosphorylation is regulated pathophysiologically are largely unknown. Recently, a growing body of evidence suggests a link between tau phosphorylation and PI3K signaling. In this study, phosphorylation, aggregation and binding to the microtubule of a mutant frontal temporal dementia and parkinsonism linked to chromosome 17 (FTDP-17 tau in the presence of tumor suppressor PTEN, a major regulatory component in PI3K signaling, were investigated. Results Phosphorylation of the human mutant FTDP-17 tau, T40RW, was evaluated using different phospho-tau specific antibodies in the presence of human wild-type or phosphatase activity null mutant PTEN. Among the evaluated phosphorylation sites, the levels of Ser214 and Thr212 phospho-tau proteins were significantly decreased in the presence of wild-type PTEN, and significantly increased when the phosphatase activity null mutant PTEN was ectopically expressed. Fractionation of the mutant tau transfected cells revealed a significantly increased level of soluble tau in cytosol when wild-type PTEN was expressed, and an elevated level of SDS-soluble tau aggregates in the presence of the mutant PTEN. In addition, the filter/trap assays detected more SDS-insoluble mutant tau aggregates in the cells overexpressing the mutant PTEN compared to those in the cells overexpressing wild-type PTEN and control DNA. This notion was confirmed by the immunocytochemical experiment which demonstrated that the overexpression of the phosphatase activity null mutant PTEN caused the mutant tau to form aggregates in the COS-7 cells. Conclusion Tumor suppressor PTEN can alleviate the phosporylation of the mutant FTDP-17 tau at specific sites, and the phosphatase activity

  9. Characterization of a splice-site mutation in the tumor suppressor gene FLCN associated with renal cancer.

    Science.gov (United States)

    Bartram, Malte P; Mishra, Tripti; Reintjes, Nadine; Fabretti, Francesca; Gharbi, Hakam; Adam, Alexander C; Göbel, Heike; Franke, Mareike; Schermer, Bernhard; Haneder, Stefan; Benzing, Thomas; Beck, Bodo B; Müller, Roman-Ulrich

    2017-05-12

    Renal cell carcinoma is among the most prevalent malignancies. It is generally sporadic. However, genetic studies of rare familial forms have led to the identification of mutations in causative genes such as VHL and FLCN. Mutations in the FLCN gene are the cause of Birt-Hogg-Dubé syndrome, a rare tumor syndrome which is characterized by the combination of renal cell carcinoma, pneumothorax and skin tumors. Using Sanger sequencing we identify a heterozygous splice-site mutation in FLCN in lymphocyte DNA of a patient suffering from renal cell carcinoma. Furthermore, both tumor DNA and DNA from a metastasis are analyzed regarding this mutation. The pathogenic effect of the sequence alteration is confirmed by minigene assays and the biochemical consequences on the protein are examined using TALEN-mediated transgenesis in cultured cells. Here we describe an FLCN mutation in a 55-year-old patient who presented himself with progressive weight loss, bilateral kidney cysts and renal tumors. He and members of his family had a history of recurrent pneumothorax during the last few decades. Histology after tumor nephrectomy showed a mixed kidney cancer consisting of elements of a chromophobe renal cell carcinoma and dedifferentiated small cell carcinoma component. Subsequent FLCN sequencing identified an intronic c.1177-5_-3delCTC alteration that most likely affected the correct splicing of exon 11 of the FLCN gene. We demonstrate skipping of exon 11 to be the consequence of this mutation leading to a shift in the reading frame and the insertion of a premature stop codon. Interestingly, the truncated protein was still expressed both in cell culture and in tumor tissue, though it was strongly destabilized and its subcellular localization differed from wild-type FLCN. Both, altered protein stability and subcellular localization could be partly reversed by blocking proteasomal and lysosomal degradation. Identification of disease-causing mutations in BHD syndrome requires the

  10. Effect of Helix aspersa extract on TNFα, NF-κB and some tumor suppressor genes in breast cancer cell line Hs578T.

    Science.gov (United States)

    El Ouar, Ibtissem; Braicu, Cornelia; Naimi, Dalila; Irimie, Alexendru; Berindan-Neagoe, Ioana

    2017-01-01

    The garden snail, Helix aspersa, is a big land snail widely found in the Mediterranean countries. It is one of the most consumed species and widely used in zootherapy. The present study was carried out to investigate for the first time the first time the antitumor activity of an aqueous extract from Helix aspersa. The effect of H. aspersa extract was studied on a triple negative breast cancer cell line Hs578T. Firstly, the morphological changes and the mode of cell death induced by the extract have been evaluated by microscopy and acridine orange/ethidium bromide staining. The effect of the extract at dilution 0.1% and 1% was then tested on some genes, regulators of cell death and proliferation like tumor necrosis factor α (TNFα), NF- κB, and the tumor suppressor genes P53 and PTEN. Data demonstrate that the extract induces necrosis in tumor cells. It enhances significantly the expression of TNFα; mRNA levels were 20 and 10 times more important in treated cells compared to nontreated cells. NF-κB and PTEN were inhibited with the dilution 1% after 8 and 24 hours of treatment. P53 expression was further inhibited but only with the highest dose, after 4, 8, and 24 hours. Our results show that H. aspersa extract has an antitumor activity against Hs578T cells; it is a potent stimulator for TNFα and a good inhibitor for NF-κB. Abbreviations used: AO: acridine orange; Bcl-2: B cell lymphoma 2. cDNA: complementary DNA; ELISA: enzyme linked immunosorbent assay; EB: ethidium bromide; IC50: the half maximal inhibitory concentration; mRNA: messenger RNA. MAPK: mitogen-activated protein kinase; NF-κB: nuclearfactorkappa B; PBS: phosphate buffered saline. PI3K: phospho-inositol 3 kinase; PTEN: phosphatase and tensin homolog; ROS: reactive oxygen species. RT-PCR: reverse transcription polymerase chain reaction; TNFα: tumor necrosis factor alpha. TNFR1: TNF receptor-1; TP53: tumor protein 53.

  11. Genetic modelling of PIM proteins in cancer: proviral tagging, cooperation with oncogenes, tumor suppressor genes and carcinogens.

    Directory of Open Access Journals (Sweden)

    Enara eAguirre

    2014-05-01

    Full Text Available The PIM proteins, which were initially discovered as proviral insertion sites in Moloney murine leukemia virus infection, are a family of highly homologous serine/threonine kinases that have been reported to be overexpressed in hematological malignancies and solid tumors. The PIM proteins have also been associated with metastasis and overall treatment responses and implicated in the regulation of apoptosis, metabolism, the cell cycle, and homing and migration, which makes these proteins interesting targets for anticancer drug discovery. The use of retroviral insertional mutagenesis and refined approaches such as complementation tagging has allowed the identification of myc, pim and a third group of genes (including bmi1 and gfi1 as complementing genes in lymphomagenesis. Moreover, mouse modeling of human cancer has provided an understanding of the molecular pathways that are involved in tumor initiation and progression at the physiological level. In particular, genetically modified mice have allowed researchers to further elucidate the role of each of the Pim isoforms in various tumor types. PIM kinases have been identified as weak oncogenes because experimental overexpression in lymphoid tissue, prostate and liver induces tumors at a relatively low incidence and with a long latency. However, very strong synergistic tumorigenicity between Pim1/2 and c-Myc and other oncogenes has been observed in lymphoid tissues. Mouse models have also been used to study whether the inhibition of specific PIM isoforms is required to prevent carcinogen-induced sarcomas, indicating that the absence of Pim2 and Pim3 greatly reduces sarcoma growth and bone invasion; the extent of this effect is similar to that observed in the absence of all 3 isoforms. This review will summarize some of the animal models that have been used to understand the isoform-specific contribution of PIM kinases to tumorigenesis.

  12. LRIG1, a 3p tumor suppressor, represses EGFR signaling and is a novel epigenetic silenced gene in colorectal cancer

    Energy Technology Data Exchange (ETDEWEB)

    Kou, Changhua, E-mail: chkoukou@hotmail.com [Department of Oncological Surgery, The Central Hospital of Xuzhou City, Xuzhou, Jiangsu 221000 (China); Zhou, Tian [Department of Gastroenterology, The Central Hospital of Xuzhou City, Xuzhou, Jiangsu 221000 (China); Han, Xilin; Zhuang, Huijie [Department of Oncological Surgery, The Central Hospital of Xuzhou City, Xuzhou, Jiangsu 221000 (China); Qian, Haixin, E-mail: qianhaixin@hotmail.com [The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215000 (China)

    2015-08-21

    Downregulation of LRIG1 was found in many types of cancer. However, data concerning the possible mechanism of LRIG1 reduction in cancers were not reported yet. To analyze the regulation and function of LRIG1 in colorectal cancer (CRC), 6 cell lines, 46 paired tissues from primary CRC cases were employed in this study. In CRC cell lines, under-expression of LRIG1 was correlated with promoter region hypermethylation, and restoration of LRIG1 was induced by 5-Aza-2'-deoxyazacytidine treatment. Subsequently, we ectopically expressed LRIG1 in LRIG1 low-expressing HCT-116 cells and suppressed LRIG1 in LRIG1 high-expressing LoVo cells. We found that over-expression of LRIG1 inhibits cell proliferation and colony formation and tumor growth, while knockdown of LRIG1 promotes cell proliferation and colony formation. Decreased and increased EGFR/AKT signaling pathway may partially explain the lower and higher rates of proliferation in CRC cells transfected with LRIG1 cDNA or shRNA. In clinical samples, we compared the methylation, mRNA and protein expression of LRIG1 in samples of CRC tissues. A significant increase in LRIG1 methylation was identified in CRC specimens compared to adjacent normal tissues and that it was negatively correlated with its mRNA and protein expression. In conclusion, LRIG1 is frequently methylated in human CRC and consequent mRNA and protein downregulation may contribute to tumor growth by activating EGFR/AKT signaling. - Highlights: • Promoter methylation of LRIG1 occurred in colorectal cancer cells and tumors. • Restoration of LRIG1 inhibits tumor growth in vitro and in vivo. • Overexpression or knockdown of LRIG1 regulates EGFR/AKT and downstream apoptosis. • Methylation of LRIG1 correlates with its mRNA and protein downregulation. • LRIG1 was firstly identified as an epigenetic target in cancer.

  13. MicroRNA-326 Functions as a Tumor Suppressor in Glioma by Targeting the Nin One Binding Protein (NOB1)

    Science.gov (United States)

    Yan, Yong; Qin, Rong; Wang, Hongxiang; Zhang, Xiaoping; Huang, Yan; Wang, Yuhai; Lu, Yicheng; Fu, Da; Chen, Juxiang

    2013-01-01

    Malignant glioma is the most common type of primary brain tumor in adults, characterized by rapid tumor growth and infiltration of tumor cells throughout the brain. Alterations in the activity of the 26S proteasome have been associated with malignant glioma cells, although the specific defects have not been identified. Recently, microRNA-326 (miR-326) was shown to play an important role in glioblastoma and breast cancer, but the underlying molecular mechanisms remain unclear. In the present study, the human Nin one binding protein (NOB1) was identified as a direct target of miR-326 and a potential oncogene in human glioma. Similar to NOB1 silencing by shRNA, overexpression of miR-326 in human glioma cell lines (A172 and U373) caused cell cycle arrest at the G1 phase, delayed cell proliferation and enhanced apoptosis. MiR-326 inhibited colony formation in soft agar and decreased growth of a xenograft tumor model, suggesting that miR-326 and NOB1 are required for tumorigenesis in vitro and in vivo. Furthermore, these processes were shown to involve the MAPK pathway. NOB1 overexpression in human glioma samples was detected by Affymetrix array analysis, and NOB1 mRNA and protein levels were shown to be increased in high-grade glioma compared to low-grade glioma and normal brain tissue. Furthermore, high levels of NOB1 were associated with unfavorable prognosis of glioma patients. Taken together, these results indicate that miR-326 and NOB1 may play an important role in the development of glioma. PMID:23869222

  14. Regulation of APC and AXIN2 expression by intestinal tumor suppressor CDX2 in colon cancer cells

    DEFF Research Database (Denmark)

    Olsen, Anders Krüger; Coskun, Mehmet; Bzorek, Michael

    2013-01-01

    Wnt signaling is often constitutively active in colorectal cancer cells. The expression of the intestinal specific transcription factor CDX2 is found to be transiently decreased in invasive cells at the tumor/stroma interface. A recent ChIP-Seq study has indicated that several Wnt signaling...... suggest that a low CDX2 level has influence on the Wnt signaling in invasive colon cancer cells possibly promoting cellular migration....

  15. Decreased expression of PBLD correlates with poor prognosis and functions as a tumor suppressor in human hepatocellular carcinoma.

    Science.gov (United States)

    Li, Aimin; Yan, Qun; Zhao, Xinmei; Zhong, Jietao; Yang, Haiyun; Feng, Zhiqiang; Du, Yanlei; Wang, Yadong; Wang, Zenan; Wang, Hong; Zhou, Yongjian; Liu, Side; Nie, Yuqiang

    2016-01-05

    Recent accumulating genomic and proteomic data suggested that decreased expression of phenazine biosynthesis-like domain-containing protein (PBLD) was frequently involved in hepatocellular carcinoma (HCC). However, there is lack of systematical investigation focusing on its expression pattern, clinical relevance, and biological function. Here, we found that PBLD was frequently decreased in HCC tissues relative to adjacent non-tumorigenic liver tissues. This decreased expression was significantly associated with poor tumor differentiation and advanced tumor stage. Kaplan-Meier analysis further showed that recurrence-free survival and overall survival were significantly worse among patients with low PBLD expression. Moreover, multivariate analyses revealed that PBLD was an independent predictor of OS and RFS. This prognostic value of PBLD was further validated in another independent cohort. We also found PBLD inhibited HCC cell growth and invasion in vitro and tumor growth in vivo. Furthermore, forced expression of PBLD influenced multiple downstream genes related to MAPK, NF-κB, EMT, and angiogenesis signaling pathways. PBLD deletion was an independent predictor of poor prognosis in patients with HCC. Elevated PBLD expression may reduce HCC cell growth and invasion via inactivation of several tumorigenesis-related signaling pathways.

  16. Down-regulation of UHRF1, associated with re-expression of tumor suppressor genes, is a common feature of natural compounds exhibiting anti-cancer properties

    Directory of Open Access Journals (Sweden)

    Schini-Kerth Valérie B

    2011-04-01

    Full Text Available Abstract Over-expressed in numerous cancers, Ubiquitin-like containing PHD Ring Finger 1 (UHRF1, also known as ICBP90 or Np95 is characterized by a SRA domain (Set and Ring Associated which is found only in the UHRF family. UHRF1 constitutes a complex with histone deacetylase 1 (HDAC1 and DNA methyltransferase 1 (DNMT1 via its SRA domain and represses the expression of several tumour suppressor genes (TSGs including p16INK4A, hMLH1, BRCA1 and RB1. Conversely, UHRF1 is regulated by other TSGs such as p53 and p73. UHRF1 is hypothetically involved in a macro-molecular protein complex called "ECREM" for "Epigenetic Code Replication Machinery". This complex would be able to duplicate the epigenetic code by acting at the DNA replication fork and by activating the right enzymatic activity at the right moment. There are increasing evidence that UHRF1 is the conductor of this replication process by ensuring the crosstalk between DNA methylation and histone modifications via the SRA and Tandem Tudor Domains, respectively. This cross-talk allows cancer cells to maintain the repression of TSGs during cell proliferation. Several studies showed that down-regulation of UHRF1 expression in cancer cells by natural pharmacological active compounds, favors enhanced expression or re-expression of TSGs, suppresses cell growth and induces apoptosis. This suggests that hindering UHRF1 to exert its role in the duplication of the methylation patterns (DNA + histones is responsible for inducing apoptosis. In this review, we present UHRF1 expression as a target of several natural products and we discuss their underlying molecular mechanisms and benefits for chemoprevention and chemotherapy.

  17. Sulforaphane Reverses the Expression of Various Tumor Suppressor Genes by Targeting DNMT3B and HDAC1 in Human Cervical Cancer Cells

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    Munawwar Ali Khan

    2015-01-01

    Full Text Available Sulforaphane (SFN may hinder carcinogenesis by altering epigenetic events in the cells; however, its molecular mechanisms are unclear. The present study investigates the role of SFN in modifying epigenetic events in human cervical cancer cells, HeLa. HeLa cells were treated with SFN (2.5 µM for a period of 0, 24, 48, and 72 hours for all experiments. After treatment, expressions of DNMT3B, HDAC1, RARβ, CDH1, DAPK1, and GSTP1 were studied using RT-PCR while promoter DNA methylation of tumor suppressor genes (TSGs was studied using MS-PCR. Inhibition assays of DNA methyl transferases (DNMTs and histone deacetylases (HDACs were performed at varying time points. Molecular modeling and docking studies were performed to explore the possible interaction of SFN with HDAC1 and DNMT3B. Time-dependent exposure to SFN decreases the expression of DNMT3B and HDAC1 and significantly reduces the enzymatic activity of DNMTs and HDACs. Molecular modeling data suggests that SFN may interact directly with DNMT3B and HDAC1 which may explain the inhibitory action of SFN. Interestingly, time-dependent reactivation of the studied TSGs via reversal of methylation in SFN treated cells correlates well with its impact on the epigenetic alterations accumulated during cancer development. Thus, SFN may have significant implications for epigenetic based therapy.

  18. Negative regulation of TLR4 via targeting of the proinflammatory tumor suppressor PDCD4 by the microRNA miR-21.

    LENUS (Irish Health Repository)

    Sheedy, FJ

    2009-11-29

    The tumor suppressor PDCD4 is a proinflammatory protein that promotes activation of the transcription factor NF-kappaB and suppresses interleukin 10 (IL-10). Here we found that mice deficient in PDCD4 were protected from lipopolysaccharide (LPS)-induced death. The induction of NF-kappaB and IL-6 by LPS required PDCD4, whereas LPS enhanced IL-10 induction in cells lacking PDCD4. Treatment of human peripheral blood mononuclear cells with LPS resulted in lower PDCD4 expression, which was due to induction of the microRNA miR-21 via the adaptor MyD88 and NF-kappaB. Transfection of cells with a miR-21 precursor blocked NF-kappaB activity and promoted IL-10 production in response to LPS, whereas transfection with antisense oligonucleotides to miR-21 or targeted protection of the miR-21 site in Pdcd4 mRNA had the opposite effect. Thus, miR-21 regulates PDCD4 expression after LPS stimulation.

  19. Transmembrane Tumor Necrosis Factor Controls Myeloid-Derived Suppressor Cell Activity via TNF Receptor 2 and Protects from Excessive Inflammation during BCG-Induced Pleurisy

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    Leslie Chavez-Galan

    2017-08-01

    Full Text Available Pleural tuberculosis (TB is a form of extra-pulmonary TB observed in patients infected with Mycobacterium tuberculosis. Accumulation of myeloid-derived suppressor cells (MDSC has been observed in animal models of TB and in human patients but their role remains to be fully elucidated. In this study, we analyzed the role of transmembrane TNF (tmTNF in the accumulation and function of MDSC in the pleural cavity during an acute mycobacterial infection. Mycobacterium bovis BCG-induced pleurisy was resolved in mice expressing tmTNF, but lethal in the absence of tumor necrosis factor. Pleural infection induced MDSC accumulation in the pleural cavity and functional MDSC required tmTNF to suppress T cells as did pleural wild-type MDSC. Interaction of MDSC expressing tmTNF with CD4 T cells bearing TNF receptor 2 (TNFR2, but not TNFR1, was required for MDSC suppressive activity on CD4 T cells. Expression of tmTNF attenuated Th1 cell-mediated inflammatory responses generated by the acute pleural mycobacterial infection in association with effective MDSC expressing tmTNF and interacting with CD4 T cells expressing TNFR2. In conclusion, this study provides new insights into the crucial role played by the tmTNF/TNFR2 pathway in MDSC suppressive activity required during acute pleural infection to attenuate excessive inflammation generated by the infection.

  20. P53 tumor suppressor is required for efficient execution of the death program following treatment with a cytotoxic limonoid obtained from Melia azedarach.

    Science.gov (United States)

    Joray, Mariana Belén; Villafañez, Florencia; González, María Laura; Crespo, María Inés; Laiolo, Jerónimo; Palacios, Sara María; Bocco, José Luis; Soria, Gastón; Carpinella, María Cecilia

    2017-11-01

    This work examines the antitumor activity of an isomeric mixture (1), composed of the limonoids meliartenin and its interchangeable isomer 12-hydroxyamoorastatin. The results obtained showed that 1 displayed outstanding cytotoxic activity against CCRF-CEM, K562, A549 and HCT116 cells, with a highly selective effect on the latter, with an IC50 value of 0.2 μM. Based on this finding, HCT116 cells were selected to study the mechanism of action of 1. Cell cycle analysis revealed that 1 induced sustained arrest in the S-phase, which was followed by the triggering of apoptotic cell death and reduced clonogenic capacity. This cytotoxicity was seen to be preceded by the upregulation of the tumor suppressor p53 and its target effector p21. In addition, it was found that p53 expression was required for efficient cell death induction, and thus that the toxicity of 1 relies mainly on p53-dependent mechanisms. Taken together, these findings position 1 as a potent antitumor agent, with potential for the development of novel chemotherapeutic drugs based on the induction of S-phase arrest. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. A mouse homologue of the Drosophila tumor suppressor l(2)tid gene defines a novel Ras GTPase-activating protein (RasGAP)-binding protein.

    Science.gov (United States)

    Trentin, G A; Yin, X; Tahir, S; Lhotak, S; Farhang-Fallah, J; Li, Y; Rozakis-Adcock, M

    2001-04-20

    p120 GTPase-activating protein (GAP) down-regulates Ras by stimulating GTP hydrolysis of active Ras. In addition to its association with Ras, GAP has been shown to bind to several tyrosine-phosphorylated proteins in cells stimulated by growth factors or expressing transforming tyrosine kinase variants. Here we report the cloning and characterization of a novel GAP-binding protein, mTid-1, a DnaJ chaperone protein that represents the murine homolog of the Drosophila tumor suppressor l(2)tid gene. Three alternatively spliced variants of mTid-1 were isolated, two of which correspond to the recently identified hTid-1(L) and hTid-1(S) forms of the human TID1 gene that exhibit opposing effects on apoptosis. We demonstrate that both cytoplasmic precursor and mitochondrial mature forms of mTid-1 associate with GAP in vivo. Interestingly, although mTid-1 is found tyrosine-phosphorylated in v-src-transformed fibroblast cells, GAP selectively binds to the unphosphorylated form of mTid-1. In immunofluorescence experiments, GAP and Tid-1 were shown to colocalize at perinuclear mitochondrial membranes in response to epidermal growth factor stimulation. These findings raise the possibility that Tid chaperone proteins may play a role in governing the conformation, activity, and/or subcellular distribution of GAP, thereby influencing its biochemical and biological activity within cells.

  2. Association of SOX4 regulated by tumor suppressor miR-30a with poor prognosis in low-grade chondrosarcoma.

    Science.gov (United States)

    Lu, Ning; Lin, Tao; Wang, Lin; Qi, Mei; Liu, Zhiyan; Dong, Hongyan; Zhang, Xiying; Zhai, Chunyan; Wang, Yan; Liu, Long; Xiang, Lei; Qi, Lei; Han, Bo; Li, Jinsong

    2015-05-01

    The sex-determining region Y-box 4 (SOX4), a transcription factor, is involved in various developmental processes. It has been reported in multiple human cancers. However, the prognostic value and its exact role in chondrosarcoma remain poorly understood. In the current study, SOX4 was overexpressed in 28 of 92 (30.4 %) interpretable chondrosarcoma patients compared with 3 of 43 (6.9 %) interpretable chondroma cases (P = 0.003). Its overexpression in chondrosarcoma was significantly associated with histological grade (P chondrosarcoma patients with low histological grade. Functionally, SOX4 silencing significantly suppressed the proliferation, migratory, and invasive capacity of SW1353 cells, suggesting an oncogenic role of SOX4 in chondrosarcoma in vitro. In an attempt of characterizing SOX4 overexpression mechanism, we identified miR-30a as a tumor suppressor that directly targets SOX4 in chondrosarcoma cells. Clinically, miR-30a expression was negatively correlated with SOX4 expression in chondrosarcoma cases. In all, we identified that SOX4 was oncogenic in chondrosarcoma and negatively regulated by miR-30a in vitro. Importantly, SOX4 overexpression may serve as a prognostic marker for patients with low-histological-grade chondrosarcoma.

  3. Silibinin modulates caudal-type homeobox transcription factor (CDX2), an intestine specific tumor suppressor to abrogate colon cancer in experimental rats.

    Science.gov (United States)

    Sangeetha, N; Nalini, N

    2015-01-01

    To authenticate the colon cancer preventive potential of silibinin, the efficacy of silibinin needs to be tested by evaluating an organ-specific biomarker. The aim of this study was to evaluate the impact of silibinin on the colonic expression of the caudal-type homeobox transcription factor (CDX2) an intestine specific tumor suppressor gene and its downstream targets in the colon of rats challenged with 1,2 dimethyl hydrazine (DMH). Rats of groups 1 and 2 were treated as control and silibinin control. Rats under groups 3 and 4 were given DMH (20 mg/kg body weight (b.w.) subcutaneously) once a week for 15 consecutive weeks from the 4th week of the experimental period. In addition, group 4 rats alone were treated with silibinin (50 mg/kg b.w. per os) everyday throughout the study period of 32 weeks. Histological investigation and messenger RNA and protein expression studies were performed in the colonic tissues of experimental rats. Findings of the study revealed that DMH administration significantly decreased the expression of CDX2 and Guanylyl cyclase C (GCC) in the colon of experimental rats. Further the decreased levels of CDX2 protein, colonic mucin content, and increased number of mast cells in the colon of DMH alone-administered rats reflects the onset of carcinogenesis. The pathological changes caused due to CDX2 suppression were attenuated by silibinin supplementation. © The Author(s) 2014.

  4. [A Systematic Analysis of Oncogene and Tumor Suppressor Genes for Panitumumab-Resistant Rectal Cancer with Wild RAS Gene - A Case Report].

    Science.gov (United States)

    Tajima, Yosuke; Shimada, Yoshifumi; Yagi, Ryoma; Okamura, Takuma; Nakano, Masato; Kameyama, Hitoshi; Nogami, Hitoshi; Maruyama, Satoshi; Takii, Yasumasa; Miura, Kohei; Ichikawa, Hiroshi; Nagahashi, Masayuki; Sakata, Jun; Kobayashi, Takashi; Wakai, Toshifumi

    2016-11-01

    A 58-year-old man was admitted with the complaint of bloody stools. Colonoscopy and computed tomography revealed a rectal cancer with a liver metastasis and multiple lung metastases. After administering a regimen comprising 3 courses of XELOX plus bevacizumab chemotherapy, the sizes of the primary and metastatic lesions decreased remarkably. Abdominoperineal resection was performed for local control of the cancer; the specimen from the initial tumor was found to be KRAS wild type. After 14 courses of XELOX chemotherapy, brain metastases were detected. Although 3 courses of IRIS plus panitumumab were administered, the liver, lung, and brain metastases spread rapidly. A comprehensive genomic analysis focused on cancer-related genes with CancerPlex®found a mutation of the BRAF gene(I326V). BRAF is a downstream molecule of KRAS in the RAS-RAF-MAPK pathway. Therefore, this mutation of the BRAF gene has the possibility of causing resistance against panitumumab that was found in this case. Furthermore, we expect that the systematic analysis of oncogene and suppressor oncogenes will enable us to choose the optimal regimen of chemotherapy or molecular targeting therapy for each patient with colorectal cancer.

  5. Linker Histone H1.2 Directs Genome-wide Chromatin Association of the Retinoblastoma Tumor Suppressor Protein and Facilitates Its Function

    Directory of Open Access Journals (Sweden)

    Shonagh Munro

    2017-06-01

    Full Text Available The retinoblastoma tumor suppressor protein pRb is a master regulator of cellular proliferation, principally through interaction with E2F and regulation of E2F target genes. Here, we describe the H1.2 linker histone as a major pRb interaction partner. We establish that H1.2 and pRb are found in a chromatin-bound complex on diverse E2F target genes. Interrogating the global influence of H1.2 on the genome-wide distribution of pRb indicated that the E2F target genes affected by H1.2 are functionally linked to cell-cycle control, consistent with the ability of H1.2 to hinder cell proliferation and the elevated levels of chromatin-bound H1-pRb complex, which occur in growth-arrested cells. Our results define a network of E2F target genes as susceptible to the regulatory influence of H1.2, where H1.2 augments global association of pRb with chromatin, enhances transcriptional repression by pRb, and facilitates pRb-dependent cell-cycle arrest.

  6. Mutations in NOTCH1 PEST domain orchestrate CCL19-driven homing of chronic lymphocytic leukemia cells by modulating the tumor suppressor gene DUSP22.

    Science.gov (United States)

    Arruga, F; Gizdic, B; Bologna, C; Cignetto, S; Buonincontri, R; Serra, S; Vaisitti, T; Gizzi, K; Vitale, N; Garaffo, G; Mereu, E; Diop, F; Neri, F; Incarnato, D; Coscia, M; Allan, J; Piva, R; Oliviero, S; Furman, R R; Rossi, D; Gaidano, G; Deaglio, S

    2017-09-01

    Even if NOTCH1 is commonly mutated in chronic lymphocytic leukemia (CLL), its functional impact in the disease remains unclear. Using CRISPR/Cas9-generated Mec-1 cell line models, we show that NOTCH1 regulates growth and homing of CLL cells by dictating expression levels of the tumor suppressor gene DUSP22. Specifically, NOTCH1 affects the methylation of DUSP22 promoter by modulating a nuclear complex, which tunes the activity of DNA methyltransferase 3A (DNMT3A). These effects are enhanced by PEST-domain mutations, which stabilize the molecule and prolong signaling. CLL patients with a NOTCH1-mutated clone showed low levels of DUSP22 and active chemotaxis to CCL19. Lastly, in xenograft models, NOTCH1-mutated cells displayed a unique homing behavior, localizing preferentially to the spleen and brain. These findings connect NOTCH1, DUSP22, and CCL19-driven chemotaxis within a single functional network, suggesting that modulation of the homing process may provide a relevant contribution to the unfavorable prognosis associated with NOTCH1 mutations in CLL.

  7. Meta-analysis of promoter methylation in eight tumor-suppressor genes and its association with the risk of thyroid cancer.

    Science.gov (United States)

    Khatami, Fatemeh; Larijani, Bagher; Heshmat, Ramin; Keshtkar, Abbasali; Mohammadamoli, Mahsa; Teimoori-Toolabi, Ladan; Nasiri, Shirzad; Tavangar, Seyed Mohammad

    2017-01-01

    Promoter methylation in a number of tumor-suppressor genes (TSGs) can play crucial roles in the development of thyroid carcinogenesis. The focus of the current meta-analysis was to determine the impact of promoter methylation of eight selected candidate TSGs on thyroid cancer and to identify the most important molecules in this carcinogenesis pathway. A comprehensive search was performed using Pub Med, Scopus, and ISI Web of Knowledge databases, and eligible studies were included. The methodological quality of the included studies was evaluated according to the Newcastle Ottawa scale table and pooled odds ratios (ORs); 95% confidence intervals (CIs) were used to estimate the strength of the associations with Stata 12.0 software. Egger's and Begg's tests were applied to detect publication bias, in addition to the "Metatrim" method. A total of 55 articles were selected, and 135 genes with altered promoter methylation were found. Finally, we included eight TSGs that were found in more than four studies (RASSF1, TSHR, PTEN, SLC5A, DAPK, P16, RARβ2, and CDH1). The order of the pooled ORs for these eight TSGs from more to less significant was CDH1 (OR = 6.73), SLC5 (OR = 6.15), RASSF1 (OR = 4.16), PTEN (OR = 3.61), DAPK (OR = 3.51), P16 (OR = 3.31), TSHR (OR = 2.93), and RARβ2 (OR = 1.50). Analyses of publication bias and sensitivity confirmed that there was very little bias. Thus, our findings showed that CDH1 and SCL5A8 genes were associated with the risk of thyroid tumor genesis.

  8. Meta-analysis of promoter methylation in eight tumor-suppressor genes and its association with the risk of thyroid cancer.

    Directory of Open Access Journals (Sweden)

    Fatemeh Khatami

    Full Text Available Promoter methylation in a number of tumor-suppressor genes (TSGs can play crucial roles in the development of thyroid carcinogenesis. The focus of the current meta-analysis was to determine the impact of promoter methylation of eight selected candidate TSGs on thyroid cancer and to identify the most important molecules in this carcinogenesis pathway. A comprehensive search was performed using Pub Med, Scopus, and ISI Web of Knowledge databases, and eligible studies were included. The methodological quality of the included studies was evaluated according to the Newcastle Ottawa scale table and pooled odds ratios (ORs; 95% confidence intervals (CIs were used to estimate the strength of the associations with Stata 12.0 software. Egger's and Begg's tests were applied to detect publication bias, in addition to the "Metatrim" method. A total of 55 articles were selected, and 135 genes with altered promoter methylation were found. Finally, we included eight TSGs that were found in more than four studies (RASSF1, TSHR, PTEN, SLC5A, DAPK, P16, RARβ2, and CDH1. The order of the pooled ORs for these eight TSGs from more to less significant was CDH1 (OR = 6.73, SLC5 (OR = 6.15, RASSF1 (OR = 4.16, PTEN (OR = 3.61, DAPK (OR = 3.51, P16 (OR = 3.31, TSHR (OR = 2.93, and RARβ2 (OR = 1.50. Analyses of publication bias and sensitivity confirmed that there was very little bias. Thus, our findings showed that CDH1 and SCL5A8 genes were associated with the risk of thyroid tumor genesis.

  9. Tumor suppressors BTG1 and IKZF1 cooperate during mouse leukemia development and increase relapse risk in B-cell precursor acute lymphoblastic leukemia patients.

    Science.gov (United States)

    Scheijen, Blanca; Boer, Judith M; Marke, René; Tijchon, Esther; van Ingen Schenau, Dorette; Waanders, Esmé; van Emst, Liesbeth; van der Meer, Laurens T; Pieters, Rob; Escherich, Gabriele; Horstmann, Martin A; Sonneveld, Edwin; Venn, Nicola; Sutton, Rosemary; Dalla-Pozza, Luciano; Kuiper, Roland P; Hoogerbrugge, Peter M; den Boer, Monique L; van Leeuwen, Frank N

    2017-03-01

    Deletions and mutations affecting lymphoid transcription factor IKZF1 (IKAROS) are associated with an increased relapse risk and poor outcome in B-cell precursor acute lymphoblastic leukemia. However, additional genetic events may either enhance or negate the effects of IKZF1 deletions on prognosis. In a large discovery cohort of 533 childhood B-cell precursor acute lymphoblastic leukemia patients, we observed that single-copy losses of BTG1 were significantly enriched in IKZF1 -deleted B-cell precursor acute lymphoblastic leukemia ( P =0.007). While BTG1 deletions alone had no impact on prognosis, the combined presence of BTG1 and IKZF1 deletions was associated with a significantly lower 5-year event-free survival ( P =0.0003) and a higher 5-year cumulative incidence of relapse ( P =0.005), when compared with IKZF1 -deleted cases without BTG1 aberrations. In contrast, other copy number losses commonly observed in B-cell precursor acute lymphoblastic leukemia, such as CDKN2A/B, PAX5, EBF1 or RB1 , did not affect the outcome of IKZF1 -deleted acute lymphoblastic leukemia patients. To establish whether the combined loss of IKZF1 and BTG1 function cooperate in leukemogenesis, Btg1 -deficient mice were crossed onto an Ikzf1 heterozygous background. We observed that loss of Btg1 increased the tumor incidence of Ikzf1 +/- mice in a dose-dependent manner. Moreover, murine B cells deficient for Btg1 and Ikzf1 +/- displayed increased resistance to glucocorticoids, but not to other chemotherapeutic drugs. Together, our results identify BTG1 as a tumor suppressor in leukemia that, when deleted, strongly enhances the risk of relapse in IKZF1 -deleted B-cell precursor acute lymphoblastic leukemia, and augments the glucocorticoid resistance phenotype mediated by the loss of IKZF1 function. Copyright© Ferrata Storti Foundation.

  10. Analysis of a new homozygous deletion in the tumor suppressor region at 3p12.3 reveals two novel intronic noncoding RNA genes.

    Science.gov (United States)

    Angeloni, Debora; ter Elst, Arja; Wei, Ming Hui; van der Veen, Anneke Y; Braga, Eleonora A; Klimov, Eugene A; Timmer, Tineke; Korobeinikova, Luba; Lerman, Michael I; Buys, Charles H C M

    2006-07-01

    Homozygous deletions or loss of heterozygosity (LOH) at human chromosome band 3p12 are consistent features of lung and other malignancies, suggesting the presence of a tumor suppressor gene(s) (TSG) at this location. Only one gene has been cloned thus far from the overlapping region deleted in lung and breast cancer cell lines U2020, NCI H2198, and HCC38. It is DUTT1 (Deleted in U Twenty Twenty), also known as ROBO1, FLJ21882, and SAX3, according to HUGO. DUTT1, the human ortholog of the fly gene ROBO, has homology with NCAM proteins. Extensive analyses of DUTT1 in lung cancer have not revealed any mutations, suggesting that another gene(s) at this location could be of importance in lung cancer initiation and progression. Here, we report the discovery of a new, small, homozygous deletion in the small cell lung cancer (SCLC) cell line GLC20, nested in the overlapping, critical region. The deletion was delineated using several polymorphic markers and three overlapping P1 phage clones. Fiber-FISH experiments revealed the deletion was approximately 130 kb. Comparative genomic sequence analysis uncovered short sequence elements highly conserved among mammalian genomes and the chicken genome. The discovery of two EST clusters within the deleted region led to the isolation of two noncoding RNA (ncRNA) genes. These were subsequently found differentially expressed in various tumors when compared to their normal tissues. The ncRNA and other highly conserved sequence elements in the deleted region may represent miRNA targets of importance in cancer initiation or progression. Published 2006 Wiley-Liss, Inc.

  11. Stability of the tumor suppressor merlin depends on its ability to bind paxillin LD3 and associate with β1 integrin and actin at the plasma membrane.

    Science.gov (United States)

    Manetti, Maria Elisa; Geden, Sandra; Bott, Marga; Sparrow, Nicklaus; Lambert, Stephen; Fernandez-Valle, Cristina

    2012-10-15

    The NF2 gene encodes a tumor suppressor protein known as merlin or schwannomin whose loss of function causes Neurofibromatosis Type 2 (NF2). NF2 is characterized by the development of benign tumors, predominantly schwannomas, in the peri