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Worsham MJ, Stephen JK, Chen KM, Havard S, Shah V, Gardner G, Schweitzer VG. Delineating an epigenetic continuum in head and neck cancer. Cancer Lett 2012; 342:178-84. [PMID: 22388100 DOI: 10.1016/j.canlet.2012.02.018] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 02/13/2012] [Accepted: 02/16/2012] [Indexed: 11/28/2022]
Abstract
A tissue field of somatic genetic alterations precedes the histopathological phenotypic changes of carcinoma. Genomic changes could be of potential use in the diagnosis and prognosis of pre-invasive squamous head and neck carcinoma (HNSCC) lesions and as markers for cancer risk assessment. Studies of sequential molecular alterations and genetic progression of pre-invasive HNSCC have not been clearly defined. Studies have shown recurring alterations at chromosome 9p21 (location of the CDKN2A) and TP53 mutations in the early stages of HNSCC. However, gene silencing via hypermethylation is still a relatively new idea in the development of HNSCC and little is known about the contribution of epigenetics to the development of neoplasia, its transformation, progression, and recurrence in HNSCC. This review examines the role of promoter hypermethylation of tumor suppressor genes in the progression continuum from benign papillomas to malignancy in HNSCC.
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Affiliation(s)
- Maria J Worsham
- Department of Otolaryngology/Head and Neck Surgery, Henry Ford Health System, Detroit, MI, United States.
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Kashima L, Idogawa M, Mita H, Shitashige M, Yamada T, Ogi K, Suzuki H, Toyota M, Ariga H, Sasaki Y, Tokino T. CHFR protein regulates mitotic checkpoint by targeting PARP-1 protein for ubiquitination and degradation. J Biol Chem 2012; 287:12975-84. [PMID: 22337872 DOI: 10.1074/jbc.m111.321828] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The mitotic checkpoint gene CHFR (checkpoint with forkhead-associated (FHA) and RING finger domains) is silenced by promoter hypermethylation or mutated in various human cancers, suggesting that CHFR is an important tumor suppressor. Recent studies have reported that CHFR functions as an E3 ubiquitin ligase, resulting in the degradation of target proteins. To better understand how CHFR suppresses cell cycle progression and tumorigenesis, we sought to identify CHFR-interacting proteins using affinity purification combined with mass spectrometry. Here we show poly(ADP-ribose) polymerase 1 (PARP-1) to be a novel CHFR-interacting protein. In CHFR-expressing cells, mitotic stress induced the autoPARylation of PARP-1, resulting in an enhanced interaction between CHFR and PARP-1 and an increase in the polyubiquitination/degradation of PARP-1. The decrease in PARP-1 protein levels promoted cell cycle arrest at prophase, supporting that the cells expressing CHFR were resistant to microtubule inhibitors. In contrast, in CHFR-silenced cells, polyubiquitination was not induced in response to mitotic stress. Thus, PARP-1 protein levels did not decrease, and cells progressed into mitosis under mitotic stress, suggesting that CHFR-silenced cancer cells were sensitized to microtubule inhibitors. Furthermore, we found that cells from Chfr knockout mice and CHFR-silenced primary gastric cancer tissues expressed higher levels of PARP-1 protein, strongly supporting our data that the interaction between CHFR and PARP-1 plays an important role in cell cycle regulation and cancer therapeutic strategies. On the basis of our studies, we demonstrate a significant advantage for use of combinational chemotherapy with PARP inhibitors for cancer cells resistant to microtubule inhibitors.
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Affiliation(s)
- Lisa Kashima
- Department of Medical Genome Sciences, Research Institute for Frontier Medicine, Sapporo Medical University, Sapporo 060-8556, Japan
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Stephen JK, Chen KM, Havard S, Harris G, Worsham MJ. Promoter methylation in head and neck tumorigenesis. Methods Mol Biol 2012; 863:187-206. [PMID: 22359294 DOI: 10.1007/978-1-61779-612-8_11] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In addition to genetic alterations of gains and losses, epigenetic events of promoter methylation appear to further undermine a destabilized genomic repertoire in squamous head and neck carcinoma (HNSCC). This chapter provides an overview of frequently methylated tumor suppressor genes in benign head and neck papillomas, primary HNSCC tumors, and HNSCC cell lines and their relevance as epigenetic markers in head and neck tumorigenesis.
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Affiliation(s)
- Josena K Stephen
- Department of Otolaryngology/Head and Neck Surgery, Henry Ford Hospital, Detroit, MI, USA
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Expression level of the mitotic checkpoint protein and G2-M cell cycle regulators and prognosis in gastrointestinal stromal tumors in the stomach. Virchows Arch 2011; 460:163-9. [PMID: 22190007 DOI: 10.1007/s00428-011-1181-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 10/26/2011] [Accepted: 11/29/2011] [Indexed: 02/01/2023]
Abstract
The biological behavior of gastrointestinal stromal tumors (GISTs) ranges from benign to malignant, and the risk of an adverse outcome is correlated with the location of the primary tumor, tumor size, and mitotic counts. Cell cycle regulators are potentially associated with the tumorigenesis and progression of GISTs. Checkpoint with forkhead and ring finger (CHFR) functions as an important checkpoint protein in the early to mid-prophase to regulate mitosis. In this study, we evaluated the expression of CHFR and several cell cycle regulators, including cyclin A, cyclin B1, cdc2, and cdk2, by immunohistochemical staining in 53 cases of primary gastric GISTs, and compared the immunohistochemical results with the clinicopathological factors or the GIST risk grades as modified by Miettinen et al. Of the 53 cases, 18 (34%) showed decreased nuclear CHFR expression. Decreased CHFR expression was correlated with higher mitotic counts [>5/50 high-power fields (HPFs)] (p = 0.039) and a high-risk grade (p = 0.0475), but not with expression of other cell cycle regulators. Higher cyclin A labeling index (LI, >1.5%), cyclin B1 LI (>0.25%), cdc2 LI (>1.16%), Ki-67 LI (>4.9%), mitotic counts (>5/50 HPF) and high-risk grade were each associated with shorter disease-free survival (p = 0.0017, p = 0.003, p = 0.0471, p = 0.002, p < 0.001, and p = 0.0017, respectively). Our results suggest that modified risk grade and increased expression of G2-M regulators such as cyclin A, cyclin B1, and cdc2 are useful for predicting the biological behavior of gastric GISTs. In addition, decreased CHFR expression may play a role in increased proliferative activity of higher grade GISTs.
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55
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CHFR: A Novel Mitotic Checkpoint Protein and Regulator of Tumorigenesis. Transl Oncol 2011; 1:57-64. [PMID: 18633460 DOI: 10.1593/tlo.08109] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2008] [Revised: 04/02/2008] [Accepted: 05/12/2008] [Indexed: 12/30/2022] Open
Abstract
Checkpoint with FHA and RING finger domains (CHFR) was first recognized as an early mitotic checkpoint protein that delayed the cell cycle in response to microtubule-targeting drugs. It is an E3 ubiquitin ligase that ubiquitinates target proteins to direct them to the proteasome for degradation or to alter their activity. To date, however, the downstream target proteins critical to CHFR's normal cellular functions largely remain unidentified with the exception of the key mitosis regulators, and oncogenes, PLK1 and Aurora A kinases. Rapidly growing evidence in mice, primary human tumors, and mammalian cell culture models indicate that CHFR may also function as a potent tumor suppressor. Interestingly, studies reported to date suggest that CHFR both controls a novel prophase checkpoint early in mitosis and regulates chromosome segregation later in mitosis to maintain genomic stability. In addition, loss of CHFR sensitizes cancer cells to microtubule poisons, altering chemoresponsiveness to taxanes and making it a potential biomarker for chemotherapeutic response. Importantly, CHFR may be one of the few proteins that are required for regulating the cell cycle and maintaining genomic instability to inhibit tumorigenesis.
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56
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Role of DNA methylation in head and neck cancer. Clin Epigenetics 2011; 2:123-50. [PMID: 22704334 PMCID: PMC3365391 DOI: 10.1007/s13148-011-0045-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Accepted: 06/14/2011] [Indexed: 02/07/2023] Open
Abstract
Head and neck cancer (HNC) is a heterogenous and complex entity including diverse anatomical sites and a variety of tumor types displaying unique characteristics and different etilogies. Both environmental and genetic factors play a role in the development of the disease, but the underlying mechanism is still far from clear. Previous studies suggest that alterations in the genes acting in cellular signal pathways may contribute to head and neck carcinogenesis. In cancer, DNA methylation patterns display specific aberrations even in the early and precancerous stages and may confer susceptibility to further genetic or epigenetic changes. Silencing of the genes by hypermethylation or induction of oncogenes by promoter hypomethylation are frequent mechanisms in different types of cancer and achieve increasing diagnostic and therapeutic importance since the changes are reversible. Therefore, methylation analysis may provide promising clinical applications, including the development of new biomarkers and prediction of the therapeutic response or prognosis. In this review, we aimed to analyze the available information indicating a role for the epigenetic changes in HNC.
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Wu J, Chen Y, Lu LY, Wu Y, Paulsen MT, Ljungman M, Ferguson DO, Yu X. Chfr and RNF8 synergistically regulate ATM activation. Nat Struct Mol Biol 2011; 18:761-8. [PMID: 21706008 PMCID: PMC3130800 DOI: 10.1038/nsmb.2078] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2010] [Accepted: 04/20/2011] [Indexed: 12/29/2022]
Abstract
Protein ubiquitination is a critical component of the DNA damage response. To study the mechanism of the DNA damage-induced ubiquitination pathway, we analyzed the impact of the loss of two E3 ubiquitin ligases, RNF8 and Chfr. Interestingly, DNA damage-induced ATM activation is suppressed in RNF8 and Chfr double-deficient (DKO) cells, and DKO mice develop thymic lymphomas that are nearly diploid but harbor clonal chromosome translocations. Moreover, DKO mice and cells are hypersensitive to ionizing radiation. We show evidence that RNF8 and Chfr synergistically regulate histone ubiquitination to control histone H4K16 acetylation through MRG15-dependent acetyltransferase complexes. Through these complexes, RNF8 and CHFR affect chromatin relaxation and modulate ATM activation and DNA damage response pathways. Collectively, our findings demonstrate that two chromatin remodeling factors, RNF8 and Chfr, function together to activate ATM and maintain genomic stability in vivo.
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Affiliation(s)
- Jiaxue Wu
- Division of Molecular Medicine and Genetics, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, USA
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58
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Yoshioka T, Kimura M, Saio M, Era S, Okano Y. Plk1 is negatively regulated by RNF8. Biochem Biophys Res Commun 2011; 410:57-61. [PMID: 21635870 DOI: 10.1016/j.bbrc.2011.05.104] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Accepted: 05/17/2011] [Indexed: 11/26/2022]
Abstract
RNF8 is a nuclear protein having an N-terminal forkhead-associated (FHA) domain and a C-terminal RING-finger (RF) domain. Depletion of RNF8 caused cell growth inhibition and cell cycle arrest at not only S but also G2/M phases. In addition, cell death was frequently observed in RNF8-depleted cells. Analyses of time-lapse microscopy revealed that the cells died in mitosis and interphase. To elucidate the RNF8 function in M phase, the Plk1 content in RNF8-depleted cells was examined. The amount of RNF8 decreased time-dependently, whereas Plk1 reciprocally increased by transfection of RNF8 siRNA. Protein contents of RNF8 and Plk1 among various cell lines were also compared. RNF8 in normal cell lines was much higher than that in many cancer cell lines. Conversely, Plk1 in normal cell lines was lower than in cancer cell lines. These results suggest that RNF8 is downregulated in many cancer cells and inversely correlated with Plk1.
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Affiliation(s)
- Takashi Yoshioka
- Department of Molecular Pathobiochemistry, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu 501-1194, Japan
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59
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Tanaka M, Chang P, Li Y, Li D, Overman M, Maru DM, Sethi S, Phillips J, Bland GL, Abbruzzese JL, Eng C. Association of CHFR Promoter Methylation with Disease Recurrence in Locally Advanced Colon Cancer. Clin Cancer Res 2011; 17:4531-40. [DOI: 10.1158/1078-0432.ccr-10-0763] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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60
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Ma T, Keller JA, Yu X. RNF8-dependent histone ubiquitination during DNA damage response and spermatogenesis. Acta Biochim Biophys Sin (Shanghai) 2011; 43:339-45. [PMID: 21444325 DOI: 10.1093/abbs/gmr016] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Histone ubiquitination regulates the chromatin structure that is important for many biological processes. Recently, ubiquitination of histones was observed during the DNA damage response (DDR), and this modification is controlled by really interesting new gene (RING) domain E3 ligase, RNF8. Together with the E2 conjugating enzyme UBC13, RNF8 catalyzes ubiquitination of the histones H2A and H2AX during the DDR, thus facilitating downstream recruitment of DDR factors, such as p53 binding protein 1 (53BP1) and breast cancer type 1 susceptibility protein (BRCA1), to the damage site. Accordingly, the RNF8 knockout mice display phenotypes associated with failed DDR, including hypersensitivity to ionizing radiation, V(D)J recombination deficiency, and a predisposition to cancer. In addition to the DDR phenotypes, RNF8 knockout mice fail to generate mature sperm during spermatogenesis, resulting in male sterility. The RNF8 knockout mice also have a drastic reduction in histone ubiquitination in the testes. These findings indicate that the role of histone ubiquitination during chromatin remodeling in two different biological events could be linked by an RNF8-dependent mechanism. Here, we review the molecular mechanism of RNF8-dependent histone ubiquitination both in DDR and spermatogenesis.
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Affiliation(s)
- Teng Ma
- Division of Molecular Medicine and Genetics, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor 48109, USA
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61
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Protected from the inside: Endogenous histone deacetylase inhibitors and the road to cancer. Biochim Biophys Acta Rev Cancer 2011; 1815:241-52. [DOI: 10.1016/j.bbcan.2011.01.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 01/16/2011] [Accepted: 01/19/2011] [Indexed: 02/06/2023]
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62
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63
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Cheong HS, Lee HC, Park BL, Kim HM, Jang MJ, Han YM, Kim SY, Kim YS, Shin HD. Epigenetic modification of retinoic acid-treated human embryonic stem cells. BMB Rep 2010; 43:830-5. [DOI: 10.5483/bmbrep.2010.43.12.830] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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64
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Oberoi J, Richards MW, Crumpler S, Brown N, Blagg J, Bayliss R. Structural basis of poly(ADP-ribose) recognition by the multizinc binding domain of checkpoint with forkhead-associated and RING Domains (CHFR). J Biol Chem 2010; 285:39348-58. [PMID: 20880844 PMCID: PMC2998101 DOI: 10.1074/jbc.m110.159855] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Revised: 08/26/2010] [Indexed: 01/07/2023] Open
Abstract
Cellular stress in early mitosis activates the antephase checkpoint, resulting in the decondensation of chromosomes and delayed mitotic progression. Checkpoint with forkhead-associated and RING domains (CHFR) is central to this checkpoint, and its activity is ablated in many tumors and cancer cell lines through promoter hypermethylation or mutation. The interaction between the PAR-binding zinc finger (PBZ) of CHFR and poly(ADP-ribose) (PAR) is crucial for a functional antephase checkpoint. We determined the crystal structure of the cysteine-rich region of human CHFR (amino acids 425-664) to 1.9 Å resolution, which revealed a multizinc binding domain of elaborate topology within which the PBZ is embedded. The PBZ of CHFR closely resembles the analogous motifs from aprataxin-like factor and CG1218-PA, which lie within unstructured regions of their respective proteins. Based on co-crystal structures of CHFR bound to several different PAR-like ligands (adenosine 5'-diphosphoribose, adenosine monophosphate, and P(1)P(2)-diadenosine 5'-pyrophosphate), we made a model of the CHFR-PAR interaction, which we validated using site-specific mutagenesis and surface plasmon resonance. The PBZ motif of CHFR recognizes two adenine-containing subunits of PAR and the phosphate backbone that connects them. More generally, PBZ motifs may recognize different numbers of PAR subunits as required to carry out their functions.
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Affiliation(s)
- Jasmeen Oberoi
- From the Section of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, United Kingdom and
| | - Mark W. Richards
- From the Section of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, United Kingdom and
| | - Simon Crumpler
- the Cancer Research UK Cancer Therapeutics Unit, Institute of Cancer Research, Haddow Laboratories, 15 Cotswold Road, Sutton, Surrey SM2 5NG, United Kingdom
| | - Nathan Brown
- the Cancer Research UK Cancer Therapeutics Unit, Institute of Cancer Research, Haddow Laboratories, 15 Cotswold Road, Sutton, Surrey SM2 5NG, United Kingdom
| | - Julian Blagg
- the Cancer Research UK Cancer Therapeutics Unit, Institute of Cancer Research, Haddow Laboratories, 15 Cotswold Road, Sutton, Surrey SM2 5NG, United Kingdom
| | - Richard Bayliss
- From the Section of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, United Kingdom and
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Targeting histone deacetyalses in the treatment of B- and T-cell malignancies. Invest New Drugs 2010; 28 Suppl 1:S58-78. [PMID: 21132350 PMCID: PMC3003796 DOI: 10.1007/s10637-010-9591-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Accepted: 10/28/2010] [Indexed: 02/06/2023]
Abstract
HDAC inhibitors (HDACI) are now emerging as one of the most promising new classes of drugs for the treatment of select forms of non-Hodgkin’s lymphoma (NHL). They are particularly active in T-cell lymphomas, possibly hodgkin’s lymphoma and indolent B cell lymphomas. Presently, two of these agents, vorinostat and romidepsin, have been approved in the US for the treatment of relapsed and refractory cutaneous T cell lymphomas (CTCL). Initially, these agents were developed with the idea that they affected transcriptional activation and thus gene expression, by modulating chromatin condensation and decondensation. It is now clear that their effects go beyond chromatin and by affecting the acetylation status of histones and other intra-cellular proteins, they modify gene expression and cellular function via multiple pathways. Gene expression profiles and functional genetic analysis has led to further understanding of the various molecular pathways that are affected by these agents including cell cycle regulation, pathways of cellular proliferation, apoptosis and angiogenesis all important in lymphomagenesis. There is also increasing data to support the effects of these agents on T cell receptor and immune function which may explain the high level of activity of these agents in T cell lymphomas and hodgkin’s lymphoma. There is ample evidence of epigenetic dysregulation in lymphomas which may underlie the mechanisms of action of these agents but how these agents work is still not clear. Current HDAC inhibitors can be divided into at least four classes based on their chemical structure. At present several of these HDAC inhibitors are in clinical trials both as single agents and in combination with chemotherapy or other biological agents. They are easy to administer and are generally well tolerated with minimal side effects. Different dosing levels and schedules and the use of isospecific HDAC inhibitors are some of the strategies that are being employed to increase the therapeutic effect of these agents in the treatment of lymphomas. There may also be class differences that translate into specific activity against different lymphoma. HDAC inhibitors will likely be incorporated into combinations of targeted therapies both in the upfront and relapsed setting for lymphomas.
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Soutto M, Peng D, Razvi M, Ruemmele P, Hartmann A, Roessner A, Schneider-Stock R, El-Rifai W. Epigenetic and genetic silencing of CHFR in esophageal adenocarcinomas. Cancer 2010; 116:4033-42. [PMID: 20564104 DOI: 10.1002/cncr.25151] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND The checkpoint with forkhead-associated domain and RING-finger domain (CHFR) is a mitotic checkpoint protein with tumor-suppressor functions. In this study, the authors investigated the epigenetic and genetic mechanisms that regulate CHFR expression in esophageal adenocarcinomas (EACs). METHODS Quantitative reverse transcriptase polymerase chain reaction analysis demonstrated downregulation of CHFR transcript in 79% of EACs (44 of 56) compared with 41 normal samples (P < .001). Immunohistochemical analysis of CHFR protein expression showed absence or weak immunostaining for CHFR in 75% of EACs (56 of 75) compared with normal tissue samples. The authors next examined the promoter DNA hypermethylation of CHFR by using quantitative bisulfite pyrosequencing technology. They detected significant CHFR promoter DNA hypermethylation in 31% of tumor samples (18 of 58) compared with normal samples (P < .001). Treatment of OE33 cells with 5-Aza-deoxycytidine led to reduction in the promoter DNA methylation levels with restoration of the CHFR mRNA expression, which confirmed promoter DNA methylation as an epigenetic mechanism regulating CHFR expression. However, they identified several EACs where the CHFR mRNA expression was silenced in the absence of notable methylation. Therefore, the authors examined the relative DNA copy number level of CHFR compared with normal samples. RESULTS The results confirmed a decrease or absence of the relative CHFR DNA copy number levels in 59% of tumor samples. Nine tumors that showed loss of CHFR mRNA expression, in absence of promoter DNA hypermethylation, demonstrated a significant loss of relative CHFR DNA copy numbers. CONCLUSIONS Taken together, their findings demonstrated that both epigenetic and genetic mechanisms were involved in silencing CHFR expression in EACs.
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Affiliation(s)
- Mohammed Soutto
- Department of Surgery, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN 37323, USA
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67
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Abstract
Aberrant DNA methylation in the genome is found in almost all types of cancer and contributes to malignant transformation by silencing multiple tumour-suppressor genes, sometimes simultaneously. Therefore, deciphering the signature of DNA methylation in each tumour is required to better understand tumour behaviour and might be of benefit for clinical diagnostics and therapy. Recent technologies for high-throughput genome-wide DNA methylation analyses are promising and potent tools for epigenetic profiling. Since epigenetic therapy is now in clinical use or trials for several types of cancers, efficient epigenetic profiling is required. In this review, the current key technologies available to assess genome-wide DNA methylation are introduced and the implications of DNA methylation profiling in human cancers are discussed.
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68
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Koga T, Takeshita M, Yano T, Maehara Y, Sueishi K. CHFR hypermethylation and EGFR mutation are mutually exclusive and exhibit contrastive clinical backgrounds and outcomes in non-small cell lung cancer. Int J Cancer 2010; 128:1009-17. [DOI: 10.1002/ijc.25447] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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69
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Hu SL, Huang DB, Sun YB, Wu L, Xu WP, Yin S, Chen J, Jiang XD, Shen G. Pathobiologic implications of methylation and expression status of Runx3 and CHFR genes in gastric cancer. Med Oncol 2010; 28:447-54. [PMID: 20300977 DOI: 10.1007/s12032-010-9467-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2010] [Accepted: 02/24/2010] [Indexed: 12/16/2022]
Abstract
Runx3 and CHFR genes were defined as tumor suppressor genes in gastric cancer (GC) recently. This paper was to investigate the roles of methylation and expression status of Runx3 and CHFR genes in GC patients. Methylation-specific polymerase chain reaction (MSP) and bisulfite DNA sequencing (BSP) were used to detect methylation status of Runx3 and CHFR genes in GC patients. The expression of Runx3 and CHFR in GC patients was analyzed by reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemical analysis. The expression of the protein and mRNA decreased remarkably in the patients with aberrant promoter methylation of Runx3 and CHFR genes. The methylation status of Runx3 and CHFR were inversely related to the tumor size, tumor invasion depth and tumor differentiation in GC patients. Moreover, the protein expression of Runx3 and CHFR were significantly correlated with tumor invasion depth and tumor differentiation, respectively. Aberrant promoter methylation of Runx3 and CHFR genes may be involved in the carcinogenesis and development of GC and may provide useful clues for the prediction of the malignant behaviors of GC.
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Affiliation(s)
- Shi-Lian Hu
- Centre for the study of Gastric Cancer, Anhui Provincial Hospital, Anhui Medical University, Hefei, People's Republic of China.
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70
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Abstract
Maintenance of genomic stability is needed for cells to survive many rounds of division throughout their lifetime. Key to the proper inheritance of intact genome is the tight temporal and spatial coordination of cell cycle events. Moreover, checkpoints are present that function to monitor the proper execution of cell cycle processes. For instance, the DNA damage and spindle assembly checkpoints ensure genomic integrity by delaying cell cycle progression in the presence of DNA or spindle damage, respectively. A checkpoint that has recently been gaining attention is the antephase checkpoint that acts to prevent cells from entering mitosis in response to a range of stress agents. We review here what is known about the pathway that monitors the status of the cells at the brink of entry into mitosis when cells are exposed to insults that threaten the proper inheritance of chromosomes. We highlight issues which are unresolved in terms of our understanding of the antephase checkpoint and provide some perspectives on what lies ahead in the understanding of how the checkpoint functions.
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71
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Abstract
DNA methylation plays a key role in the silencing of cancer-related genes, thereby affecting numerous cellular processes, including the cell cycle checkpoint, apoptosis, signal transduction, cell adhesion, and angiogenesis. DNA methylation also affects the expression of genes involved in maintaining the integrity of the genome through DNA repair and detoxification of reactive oxygen species. Here, we discuss how epigenetic changes lead to genetic alterations, including microsatellite instability and nucleotide and chromosomal alterations. Epigenetic inactivation of hMLH1 is a major cause of microsatellite instability in sporadic colorectal cancers, and germline epimutation of hMLH1 and hMSH2 is a cause of hereditary nonpolyposis colorectal cancers, which do not show mutation of mismatch repair genes. Epigenetic inactivation of MGMT is often associated with G:C-to-A:T mutations in K-ras and p53, while epigenetic inactivation of BRCA1, WRN, FANCF, and CHFR impairs the machinery involved in maintaining genomic integrity. Epigenetic alteration of the genes involved in the induction of senescence is often associated with cancers showing mutations in the Ras signaling pathway. In addition to regional hypermethylation, global hypomethylation is also a common feature of tumors. Hypomethylation of short and long interspersed repetitive elements has been reported, and hypomethylation affecting the integrity of the genome has been observed in ICF syndrome and various cancers. Dissection of the epigenetic drivers of genetic instability may be important for the development of novel approaches to the treatment of cancer.
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Affiliation(s)
- Minoru Toyota
- Department of Biochemistry, Sapporo Medical University, Sapporo, Japan
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72
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DNA methylation of developmental genes in pediatric medulloblastomas identified by denaturation analysis of methylation differences. Proc Natl Acad Sci U S A 2009; 107:234-9. [PMID: 19966297 DOI: 10.1073/pnas.0907606106] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
DNA methylation might have a significant role in preventing normal differentiation in pediatric cancers. We used a genomewide method for detecting regions of CpG methylation on the basis of the increased melting temperature of methylated DNA, termed denaturation analysis of methylation differences (DAMD). Using the DAMD assay, we find common regions of cancer-specific methylation changes in primary medulloblastomas in critical developmental regulatory pathways, including Sonic hedgehog (Shh), Wingless (Wnt), retinoic acid receptor (RAR), and bone morphogenetic protein (BMP). One of the commonly methylated loci is the PTCH1-1C promoter, a negative regulator of the Shh pathway that is methylated in both primary patient samples and human medulloblastoma cell lines. Treatment with the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine (5-aza-dC) increases the expression of PTCH1 and other methylated loci. Whereas genetic mutations in PTCH1 have previously been shown to lead to medulloblastoma, our study indicates that epigenetic silencing of PTCH1, and other critical developmental loci, by DNA methylation is a fundamental process of pediatric medulloblastoma formation. This finding warrants strong consideration for DNA demethylating agents in future clinical trials for children with this disease.
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73
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Fu Z, Regan K, Zhang L, Muders MH, Thibodeau SN, French A, Wu Y, Kaufmann SH, Lingle WL, Chen J, Tindall DJ. Deficiencies in Chfr and Mlh1 synergistically enhance tumor susceptibility in mice. J Clin Invest 2009; 119:2714-24. [PMID: 19690386 DOI: 10.1172/jci37405] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Accepted: 06/24/2009] [Indexed: 01/17/2023] Open
Abstract
Genetic instability, which leads to an accumulation of various genetic abnormalities, has been considered an essential component of the human neoplasic transformation process. However, the molecular basis of genomic instability during tumorigenesis remains incompletely understood. Growing evidence indicates that checkpoint with forkhead and ring finger domains (CHFR), a recently identified mitotic checkpoint protein, plays an important role in maintaining chromosome integrity and functions as a tumor suppressor. In this study, we used high-throughput technology to conduct gene expression profiling of human colon cancers and found that loss of CHFR expression frequently occurred in colon cancers with high microsatellite instability (MSI-H). Downregulation of CHFR expression was closely associated with overexpression of Aurora A, an important mitotic kinase. Mice with deficiencies in both Chfr and Mlh1 (the gene that encodes the DNA mismatch-repair protein Mlh1) displayed dramatically higher incidence of spontaneous tumors relative to mice deficient for only one of these genes. These results suggest that defects in both Chfr and Mlh1 synergistically increase predisposition to tumorigenesis.
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Affiliation(s)
- Zheng Fu
- Department of Urology, Mayo Clinic College of Medicine, Rochester, Minnesota, USA.
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74
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CHFR, a potential tumor suppressor, downregulates interleukin-8 through the inhibition of NF-κB. Oncogene 2009; 28:2643-53. [DOI: 10.1038/onc.2009.123] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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75
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Toyota M, Suzuki H, Yamashita T, Hirata K, Imai K, Tokino T, Shinomura Y. Cancer epigenomics: implications of DNA methylation in personalized cancer therapy. Cancer Sci 2009; 100:787-91. [PMID: 19236379 PMCID: PMC11159488 DOI: 10.1111/j.1349-7006.2009.01095.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Genetic alterations in cancer can provide information for predicting a tumor's sensitivity to chemotherapeutic drugs. But although such information is certainly useful, the relatively low frequency of mutations seen in many cancers limits the utility of pharmacogenomics in large numbers of cancer patients, necessitating consideration of other approaches. Epigenetic changes such as DNA methylation are a hallmark of human cancers. Methylation of genes involved in DNA repair and maintaining genome integrity (e.g. MGMT, hMLH1, WRN, and FANCF), and cell-cycle checkpoint genes (e.g. CHFR and 14-3-3 sigma, CDK10, and p73), all reportedly influence the sensitivity to chemotherapeutic drugs, suggesting that DNA methylation could serve as a molecular marker for predicting the responsiveness of tumors to chemotherapy. However, the comprehensive study of pharmacoepigenomics awaits the advent of genome-wide analysis of DNA methylation using microarrays and next-generation sequencers.
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Affiliation(s)
- Minoru Toyota
- Department of Biochemistry, Cancer Research Institute, Sapporo Medical University, Sapporo 060-8556, Japan.
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76
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Rao CV, Yamada HY, Yao Y, Dai W. Enhanced genomic instabilities caused by deregulated microtubule dynamics and chromosome segregation: a perspective from genetic studies in mice. Carcinogenesis 2009; 30:1469-74. [PMID: 19372138 DOI: 10.1093/carcin/bgp081] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Aneuploidy is defined as numerical abnormalities of chromosomes and is frequently (>90%) present in solid tumors. In general, tumor cells become increasingly aneuploid with tumor progression. It has been proposed that enhanced genomic instability at least contributes significantly to, if not requires, tumor progression. Two major modes for genomic instability are microsatellite instability (MIN) and chromosome instability (CIN). MIN is associated with DNA-level defects (e.g. mismatch repair defects), and CIN is associated with mitotic errors such as chromosome mis-segregation. The mitotic spindle assembly checkpoint (SAC) ensures that cells with defective mitotic spindles or defective interaction between the spindles and kinetochores do not initiate chromosomal segregation during mitosis. Thus, the SAC functions to protect the cell from chromosome mis-segregation and anueploidy during cell division. A loss of the SAC function results in gross aneuploidy, a condition from which cells with an advantage for proliferation will be selected. During the past several years, a flurry of genetic studies in mice and humans strongly support the notion that an impaired SAC causes enhanced genomic instabilities and tumor development. This review article summarizes the roles of key spindle checkpoint proteins {i.e. Mad1/Mad1L1, Mad2/Mad2L1, BubR1/Bub1B, Bub3/Bub3 [conventional protein name (yeast or human)/mouse protein name]} and the modulators (i.e. Chfr/Chfr, Rae1/Rae1, Nup98/Nup98, Cenp-E/CenpE, Apc/Apc) in genomic stability and suppression of tumor development, with a focus on information from genetically engineered mouse model systems. Further elucidation of molecular mechanisms of the SAC signaling has the potential for identifying new targets for rational anticancer drug design.
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Affiliation(s)
- Chinthalapally V Rao
- Department of Medicine, Hematology/Oncology Section, University of Oklahoma Cancer Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
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77
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Tomita M, Toyota M, Ishikawa C, Nakazato T, Okudaira T, Matsuda T, Uchihara JN, Taira N, Ohshiro K, Senba M, Tanaka Y, Ohshima K, Saya H, Tokino T, Mori N. Overexpression of Aurora A by loss of CHFR gene expression increases the growth and survival of HTLV-1-infected T cells through enhanced NF-kappaB activity. Int J Cancer 2009; 124:2607-15. [PMID: 19230025 DOI: 10.1002/ijc.24257] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) is the etiologic agent for adult T-cell leukemia (ATL). Aurora A, a mitotic checkpoint protein, is overexpressed in human cancer cells. The cell cycle-dependent turnover of Aurora A is regulated by E3 ubiquitin ligases such as checkpoint with fork head-associated and ring finger (CHFR). Here, we found overexpression of Aurora A protein in HTLV-1-infected T-cell lines and primary ATL cells. The expression of CHFR mRNA was reduced in these cells by abnormal methylation of CHFR promoter region. Knockdown of Aurora A using small interfering RNA suppressed the growth of HTLV-1-infected T-cell line. Transfection of Aurora A expression plasmid enhanced Tax-induced nuclear factor-kappaB (NF-kappaB) reporter activity. Transfection of CHFR expression plasmid into an HTLV-1-infected T-cell line reduced cell growth, Aurora A protein level and constitutive NF-kappaB reporter activity. Aurora kinase inhibitor suppressed the growth and survival of HTLV-1-infected T-cell lines and primary ATL cells. It also reduced constitutive NF-kappaB activity in an HTLV-1-infected T-cell line by reducing IkappaB kinase beta phosphorylation and the expression of antiapoptotic protein survivin. Our results suggested that loss of CHFR expression resulted to accumulation of Aurora A, which increased NF-kappaB activity. These findings highlight the critical role of Aurora A in HTLV-1-infected T cells, making this molecule a potentially suitable target for future therapies for ATL.
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Affiliation(s)
- Mariko Tomita
- Division of Molecular Virology and Oncology, Graduate School of Medicine, University of the Ryukyus, Nishihara, Okinawa, Japan
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78
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79
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Maddika S, Sy SMH, Chen J. Functional interaction between Chfr and Kif22 controls genomic stability. J Biol Chem 2009; 284:12998-3003. [PMID: 19321445 DOI: 10.1074/jbc.m900333200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Proper activation of checkpoint during mitotic stress is an important mechanism to prevent genomic instability. Chfr (Check point protein with FHA (Forkhead-associated domain) and RING domains) is a ubiquitin-protein isopeptide ligase (E3) that is important for the control of an early mitotic checkpoint, which delays entry into metaphase in response to mitotic stress. Because several lines of evidence indicate that Chfr is a potential tumor suppressor, it is critically important for us to identify Chfr substrates and understand how Chfr may regulate these substrates, control mitotic transitions, and thus, act as a tumor suppressor in vivo. Here, we report the discovery of a new Chfr-associated protein Kif22, a chromokinesin that binds to both DNA and microtubules. We demonstrated that Kif22 is a novel substrate of Chfr. We showed that Chfr-mediated Kif22 down-regulation is critical for the maintenance of chromosome stability. Collectively, our results reveal a new substrate of Chfr that plays a role in the maintenance of genome integrity.
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Affiliation(s)
- Subbareddy Maddika
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
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80
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Smits KM, Cleven AHG, Weijenberg MP, Hughes LAE, Herman JG, de Bruïne AP, van Engeland M. Pharmacoepigenomics in colorectal cancer: a step forward in predicting prognosis and treatment response. Pharmacogenomics 2009; 9:1903-16. [PMID: 19072647 DOI: 10.2217/14622416.9.12.1903] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Despite therapeutic innovations and increasing education on lifestyle to prevent colorectal cancer, it is still one of the most common cancer types, and for men the second cause of cancer-related death. Lately, much attention has been given to identify molecular markers involved in colorectal cancer prognosis and treatment with the aim to develop a more accurate classification system based on (epi)genetic alterations and, in addition, find markers that could potentially enhance management of colorectal cancer by predicting treatment response in advance. Although many genetic markers have been claimed to have prognostic or predictive influence, results are often inconclusive and, with some exception, they are not used in standard practice. Epigenetic alterations have received less attention although they are probably even more interesting as they can potentially be reversed through drug treatment. This review describes the current knowledge on the prognostic and predictive value of epigenetic markers in colorectal cancer.
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Affiliation(s)
- Kim M Smits
- Department of Epidemiology, GROW-School for Oncology and Developmental Biology, Maastricht University, The Netherlands
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81
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Suzuki H, Toyota M, Kondo Y, Shinomura Y. Inflammation-related aberrant patterns of DNA methylation: detection and role in epigenetic deregulation of cancer cell transcriptome. Methods Mol Biol 2009; 512:55-69. [PMID: 19347273 DOI: 10.1007/978-1-60327-530-9_5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
It is now apparent that epigenetic abnormalities, in particular altered DNA methylation, play a crucial role in the development and progression of human cancers. DNA hypermethylation at promoter CpG islands is now recognized as a third mechanism by which inactivation of tumor suppressor genes occurs. Aberrant CpG island hypermethylation is also frequently observed in chronic inflammation and precancerous lesions, which suggests that it is an early event in tumorigenesis that could serve as a useful tumor marker. A variety of screening techniques have been developed for genome-wide screening of methylation status. Of those, transcriptome analysis coupled with pharmacological unmasking has emerged as a powerful tool for revealing DNA methylation patterns in cancer cells and identifying new tumor marker candidates.
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Affiliation(s)
- Hiromu Suzuki
- First Department of Internal Medicine, Sapporo Medical University, Sapporo, Japan
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82
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Mahajan A, Yuan C, Lee H, Chen ESW, Wu PY, Tsai MD. Structure and function of the phosphothreonine-specific FHA domain. Sci Signal 2008; 1:re12. [PMID: 19109241 DOI: 10.1126/scisignal.151re12] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The forkhead-associated (FHA) domain is the only known phosphoprotein-binding domain that specifically recognizes phosphothreonine (pThr) residues, distinguishing them from phosphoserine (pSer) residues. In contrast to its very strict specificity toward pThr, the FHA domain recognizes very diverse patterns in the residues surrounding the pThr residue. For example, the FHA domain of Ki67, a protein associated with cellular proliferation, binds to an extended target surface involving residues remote from the pThr, whereas the FHA domain of Dun1, a DNA damage-response kinase, specifically recognizes a doubly phosphorylated Thr-Gln (TQ) cluster by virtue of its possessing two pThr-binding sites. The FHA domain exists in various proteins with diverse functions and is particularly prevalent among proteins involved in the DNA damage response. Despite a very short history, a number of unique structural and functional properties of the FHA domain have been uncovered. This review highlights the diversity of biological functions of the FHA domain-containing proteins and the structural bases for the novel binding specificities and multiple binding modes of FHA domains.
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Affiliation(s)
- Anjali Mahajan
- Biophysics Program, Ohio State University, Columbus, OH 43210, USA
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83
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Suzuki H, Tokino T, Shinomura Y, Imai K, Toyota M. DNA methylation and cancer pathways in gastrointestinal tumors. Pharmacogenomics 2008; 9:1917-28. [DOI: 10.2217/14622416.9.12.1917] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Cancer is fundamentally a genetic and epigenetic disease that requires the accumulation of genomic alterations that inactivate tumor suppressors and activate proto-oncogenes. In addition to genetic mutation or allelic loss, epigenetic gene silencing associated with DNA methylation is now recognized as an alternative mechanism by which tumor suppressor genes are inactivated. In gastrointestinal cancers, for example, DNA methylation frequently alters the activity in a number of important signaling pathways by silencing expression of genes encoding Wnt antagonists, negative Ras effectors and p53 targets. Indeed, the list of genes aberrantly methylated in cancer is growing, and methylation of a p53 target micoRNA gene has recently been demonstrated. Sites of DNA methylation could be promising markers and targets for risk assessment, early detection and treatment of cancer.
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Affiliation(s)
- Hiromu Suzuki
- First department of Internal Medicine, Sapporo Medical University, Japan
- Department of Biochemistry, Sapporo Medical University, S1, W17, Chuo-Ku, Sapporo, 060–8556, Japan
| | - Takashi Tokino
- Department of Molecular Biology, Cancer Research Institute, Sapporo Medical University, Japan
| | - Yasuhisa Shinomura
- First department of Internal Medicine, Sapporo Medical University, Japan
| | | | - Minoru Toyota
- Department of Biochemistry, Sapporo Medical University, S1, W17, Chuo-Ku, Sapporo, 060–8556, Japan
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84
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Loss of CHFR in human mammary epithelial cells causes genomic instability by disrupting the mitotic spindle assembly checkpoint. Neoplasia 2008; 10:643-52. [PMID: 18592005 DOI: 10.1593/neo.08176] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Revised: 04/23/2008] [Accepted: 04/24/2008] [Indexed: 01/01/2023] Open
Abstract
CHFR is an E3 ubiquitin ligase and an early mitotic checkpoint protein implicated in many cancers and in the maintenance of genomic stability. To analyze the role of CHFR in genomic stability, by siRNA, we decreased its expression in genomically stable MCF10A cells. Lowered CHFR expression quickly led to increased aneuploidy due to many mitotic defects. First, we confirmed that CHFR interacts with the mitotic kinase Aurora A to regulate its expression. Furthermore, we found that decreased CHFR led to disorganized multipolar mitotic spindles. This was supported by the finding that CHFR interacts with alpha-tubulin and can regulate its ubiquitination in response to nocodazole and the amount of acetylated alpha-tubulin, a component of the mitotic spindle. Finally, we found a novel CHFR interacting protein, the spindle checkpoint protein MAD2. Decreased CHFR expression resulted in the mislocalization of both MAD2 and BUBR1 during mitosis and impaired MAD2/CDC20 complex formation. Further evidence of a compromised spindle checkpoint was the presence of misaligned metaphase chromosomes, lagging anaphase chromosomes, and defective cytokinesis in CHFR knockdown cells. Importantly, our results suggest a novel role for CHFR regulating chromosome segregation where decreased expression, as seen in cancer cells, contributes to genomic instability by impairing the spindle assembly checkpoint.
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85
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Takeshita M, Koga T, Takayama K, Kouso H, Nishimura-Ikeda Y, Yoshino I, Maehara Y, Nakanishi Y, Sueishi K. CHFR expression is preferentially impaired in smoking-related squamous cell carcinoma of the lung, and the diminished expression significantly harms outcomes. Int J Cancer 2008; 123:1623-30. [PMID: 18623126 DOI: 10.1002/ijc.23673] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Loss of tumor suppressors and activation of oncogenes lead to carcinogenesis. Abnormal expression of CHFR, a novel checkpoint gene, or of Aurora kinases, key regulators of mitosis, has been detected in a variety of solid tumors. Recently, CHFR has been revealed to ensure chromosomal stability by controlling the expression level of Aurora-A in vitro. However, the frequency of aberrant expression of these proteins and the association with clinicopathologic parameters remain poorly defined in nonsmall-cell lung cancer (NSCLC). In this study, we investigated the immunohistochemical protein expression of CHFR and Aurora-A in 157 NSCLC cases and evaluated the association between clinicopathologic parameters statistically. The relationship between CHFR protein and mRNA levels and the association between this relationship and promoter methylation of the CHFR gene were also examined in 20 frozen sections of NSCLC. Overexpression of Aurora-A and reduced expression of CHFR were found in 94 cases (59.8%) and 62 cases (39%) of NSCLC, respectively, and those were significantly correlated with tumor differentiation and size. Moreover, diminished CHFR expression was significantly associated with smoking-related squamous cell carcinoma cases and poor prognosis. Multivariate analysis revealed that CHFR expression was an independent prognostic factor. A statistical correlation was evident between CHFR protein and mRNA expression. In conclusion, our results suggest the aberrant expression of Aurora-A and/or of CHFR contributed to the increase in the malignant potential of NSCLC. We also revealed that CHFR expression was predominantly impaired in smoking-related squamous cell carcinoma and might be a useful prognostic marker in NSCLC.
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Affiliation(s)
- Masafumi Takeshita
- Division of Pathophysiological and Experimental Pathology, Department of Pathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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86
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Toyota M, Suzuki H, Sasaki Y, Maruyama R, Imai K, Shinomura Y, Tokino T. Epigenetic silencing of microRNA-34b/c and B-cell translocation gene 4 is associated with CpG island methylation in colorectal cancer. Cancer Res 2008; 68:4123-32. [PMID: 18519671 DOI: 10.1158/0008-5472.can-08-0325] [Citation(s) in RCA: 492] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Altered expression of microRNA (miRNA) is strongly implicated in cancer, and recent studies have shown that, in cancer, expression of some miRNAs cells is silenced in association with CpG island hypermethylation. To identify epigenetically silenced miRNAs in colorectal cancer (CRC), we screened for miRNAs induced in CRC cells by 5-aza-2'-deoxycytidine (DAC) treatment or DNA methyltransferase knockout. We found that miRNA-34b (miR-34b) and miR-34c, two components of the p53 network, are epigenetically silenced in CRC; that this down-regulation of miR-34b/c is associated with hypermethylation of the neighboring CpG island; and that DAC treatment rapidly restores miR-34b/c expression. Methylation of the miR-34b/c CpG island was frequently observed in CRC cell lines (nine of nine, 100%) and in primary CRC tumors (101 of 111, 90%), but not in normal colonic mucosa. Transfection of precursor miR-34b or miR-34c into CRC cells induced dramatic changes in the gene expression profile, and there was significant overlap between the genes down-regulated by miR-34b/c and those down-regulated by DAC. We also found that the miR-34b/c CpG island is a bidirectional promoter which drives expression of both miR-34b/c and B-cell translocation gene 4 (BTG4); that methylation of the CpG island is also associated with transcriptional silencing of BTG4; and that ectopic expression of BTG4 suppresses colony formation by CRC cells. Our results suggest that miR-34b/c and BTG4 are novel tumor suppressors in CRC and that the miR-34b/c CpG island, which bidirectionally regulates miR-34b/c and BTG4, is a frequent target of epigenetic silencing in CRC.
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Affiliation(s)
- Minoru Toyota
- First Department of Internal Medicine, Cancer Research Institute, Sapporo Medical University, Sapporo, Japan
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87
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Chou J, Lin YC, Kim J, You L, Xu Z, He B, Jablons DM. Nasopharyngeal carcinoma--review of the molecular mechanisms of tumorigenesis. Head Neck 2008; 30:946-63. [PMID: 18446839 PMCID: PMC3046044 DOI: 10.1002/hed.20833] [Citation(s) in RCA: 240] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Nasopharyngeal carcinoma (NPC) is a head and neck cancer rare throughout most of the world but common in certain geographic areas, such as southern Asia. While environmental factors and genetic susceptibility play important roles in NPC pathogenesis, the Epstein-Barr virus in particular has been implicated in the molecular abnormalities leading to NPC. There is upregulation of cellular proliferation pathways such as the Akt pathway, mitogen-activated protein kinases, and the Wnt pathway. Cell adhesion is compromised due to abnormal E-cadherin and beta-catenin function. Aberrations in cell cycle are due to dysregulation of factors such as p16, cyclin D1, and cyclin E. Anti-apoptotic mechanisms are also upregulated. There are multiple abnormalities unique to NPC that are potential targets for novel treatments.
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Affiliation(s)
- Josephine Chou
- Thoracic Oncology Laboratory, Department of Surgery, Comprehensive Cancer Center, University of California, San Francisco, California 94115, USA
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88
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Abstract
Chfr is a checkpoint protein that plays an important function in cell cycle progression and tumor suppression, although its exact role and regulation are unclear. Previous studies have utilized overexpression of Chfr to determine the signaling pathway of this protein in vivo. In this study, we demonstrate, by using three different antibodies against Chfr, that the endogenous and highly overexpressed ectopic Chfr protein is localized and regulated differently in cells. Endogenous and lowly expressed ectopic Chfr are cytoplasmic and localize to the spindle during mitosis. Higher expression of ectopic Chfr correlates with a shift in the localization of this protein to the nucleus/PML bodies, and with a block of cell proliferation. In addition, endogenous and lowly expressed ectopic Chfr is stable throughout the cell cycle, whereas when highly expressed, ectopic Chfr is actively degraded during S-G2/M phases in an autoubiquitination and proteasome-dependent manner. A two-hybrid screen identified TCTP as a possible Chfr-interacting partner. Biochemical analysis with the endogenous proteins confirmed this interaction and identified beta-tubulin as an additional partner for Chfr, supporting the mitotic spindle localization of Chfr. The Chfr-TCTP interaction was stable throughout the cell cycle, but it could be diminished by the complete depolymerization of the microtubules, providing a possible mechanism where Chfr could be the sensor that detects microtubule disruption and then activates the prophase checkpoint.
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89
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Coding region polymorphisms in the CHFR mitotic stress checkpoint gene are associated with colorectal cancer risk. Cancer Lett 2008; 260:170-9. [PMID: 18079053 DOI: 10.1016/j.canlet.2007.10.036] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2007] [Revised: 09/26/2007] [Accepted: 10/30/2007] [Indexed: 11/21/2022]
Abstract
CHFR was recently identified as an early mitotic checkpoint that delays transition to metaphase in response to mitotic stress. Although studies have shown that CHFR is relevant to tumorigenesis, no previous report has investigated whether polymorphisms in the CHFR gene are associated with the risk of cancer development. Here, we genotyped polymorphisms in the CHFR gene and analyzed the possible associations of single polymorphisms and haplotypes with the risk and clinicopathological characteristics of colorectal cancer. Six coding SNPs in the CHFR gene were genotyped in 462 colorectal cancer patients and 245 healthy normal controls, using either the TaqMan assay or direct sequencing. Our results revealed that the V539M polymorphism was significantly associated with a lower risk of colorectal cancer (P=0.03; OR, 0.533; 95% CI, 0.302-0.94), and significantly correlated with no distant metastasis (M0 stage), different TNM stage, and microsatellite instability (MSI) among the colorectal cancer patients. Among the five tested haplotypes, hap 10 (TGACTA) was significantly associated with a lower risk of colorectal cancer (P=0.017; OR, 0.496; 95% CI, 0.279-0.883), and colorectal cancer patients carrying this haplotype showed no distant metastasis, different TNM stage, and microsatellite instability at a significantly higher frequency. These results reveal for the first time that polymorphisms in the CHFR gene are associated with colorectal cancer susceptibility.
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90
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Alumkal JJ, Zhang Z, Humphreys EB, Bennett C, Mangold LA, Carducci MA, Partin AW, Garrett-Mayer E, DeMarzo AM, Herman JG. Effect of DNA methylation on identification of aggressive prostate cancer. Urology 2008; 72:1234-9. [PMID: 18387661 DOI: 10.1016/j.urology.2007.12.060] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2007] [Revised: 11/02/2007] [Accepted: 12/13/2007] [Indexed: 10/22/2022]
Abstract
OBJECTIVES Biochemical (prostate-specific antigen) recurrence of prostate cancer after radical prostatectomy remains a major problem. Better biomarkers are needed to identify high-risk patients. DNA methylation of promoter regions leads to gene silencing in many cancers. In this study, we assessed the effect of DNA methylation on the identification of recurrent prostate cancer. METHODS We studied the methylation status of 15 pre-specified genes using methylation-specific polymerase chain reaction on tissue samples from 151 patients with localized prostate cancer and at least 5 years of follow-up after prostatectomy. RESULTS On multivariate logistic regression analysis, a high Gleason score and involvement of the capsule, lymph nodes, seminal vesicles, or surgical margin were associated with an increased risk of biochemical recurrence. Methylation of CDH13 by itself (odds ratio 5.50, 95% confidence interval [CI] 1.34 to 22.67; P = 0.02) or combined with methylation of ASC (odds ratio 5.64, 95% CI 1.47 to 21.7; P = 0.01) was also associated with an increased risk of biochemical recurrence. The presence of methylation of ASC and/or CDH13 yielded a sensitivity of 72.3% (95% CI 57% to 84.4%) and negative predictive value of 79% (95% CI 66.8% to 88.3%), similar to the weighted risk of recurrence (determined from the lymph node status, seminal vesicle status, surgical margin status, and postoperative Gleason score), a powerful clinicopathologic prognostic score. However, 34% (95% CI 21% to 49%) of the patients with recurrence were identified by the methylation profile of ASC and CDH13 rather than the weighted risk of recurrence. CONCLUSIONS The results of our study have shown that methylation of CDH13 alone or combined with methylation of ASC is independently associated with an increased risk of biochemical recurrence after radical prostatectomy even considering the weighted risk of recurrence score. These findings should be validated in an independent, larger cohort of patients with prostate cancer who have undergone radical prostatectomy.
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Affiliation(s)
- Joshi J Alumkal
- Division of Hematology and Medical Oncology, Oregon Health and Science University, Portland, Oregon, USA
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91
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Fukuda T, Kondo Y, Nakagama H. The anti-proliferative effects of the CHFR depend on the forkhead associated domain, but not E3 ligase activity mediated by ring finger domain. PLoS One 2008; 3:e1776. [PMID: 18335050 PMCID: PMC2258000 DOI: 10.1371/journal.pone.0001776] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2008] [Accepted: 02/12/2008] [Indexed: 12/11/2022] Open
Abstract
The CHFR protein comprises fork head associated- (FHA) and RING-finger (RF) domain and is frequently downregulated in human colon and gastric cancers up to 50%. The loss of CHFR mRNA expression is a consequence of promoter methylation, suggesting a tumor suppressor role for this gene in gastrointestinal carcinogenesis. In terms of the biological functions of CHFR, it has been shown to activate cell cycle checkpoint when cells are treated with microtubule depolymerizing agents. Furthermore, CHFR was reported to have E3 ligase activity and promote ubiquitination and degradation of oncogenic proteins such as Aurora A and polo-like kinase 1. However, molecular pathways involved in the tumor suppressive function of CHFR are not yet clear since the two established roles of this protein are likely to inhibit cell growth. In this study, we have identified that the FHA domain of CHFR protein is critical for growth suppressive properties, whereas the RF and cysteine rich domains (Cys) are not required for this function. In contrast, the RF and Cys domains are essential for E3 ligase activity of CHFR. By the use of a cell cycle checkpoint assay, we also confirmed that the FHA domain of CHFR plays an important role in initiating a cell cycle arrest at G2/M, indicating a functional link exists between the anti-proliferative effects and checkpoint function of this tumor suppressor protein via this domain. Collectively, our data show that the checkpoint function of the FHA domain of CHFR is a core component of anti-proliferative properties against the gastrointestinal carcinogenesis.
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Affiliation(s)
- Tomokazu Fukuda
- Biochemistry Division, National Cancer Center Research Institute, Tokyo, Japan
| | - Yasuyuki Kondo
- Biochemistry Division, National Cancer Center Research Institute, Tokyo, Japan
| | - Hitoshi Nakagama
- Biochemistry Division, National Cancer Center Research Institute, Tokyo, Japan
- * E-mail:
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92
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Qiu GH, Salto-Tellez M, Ross JA, Yeo W, Cui Y, Wheelhouse N, Chen GG, Harrison D, Lai P, Tao Q, Hooi SC. The tumor suppressor gene DLEC1 is frequently silenced by DNA methylation in hepatocellular carcinoma and induces G1 arrest in cell cycle. J Hepatol 2008; 48:433-41. [PMID: 18191269 DOI: 10.1016/j.jhep.2007.11.015] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Revised: 11/03/2007] [Accepted: 11/13/2007] [Indexed: 01/15/2023]
Abstract
BACKGROUND/AIMS The chromosome locus 3p21.3 is a "hot-spot" for chromosomal aberrations and loss of heterozygosity in cancers. The 35 genes mapped to the AP20 subregion of this locus were screened for their expression to identify candidate tumor suppressor genes. DLEC1 was selected for further characterization in primary hepatocellular carcinomas and cell lines. METHODS RT-PCR and methylation-specific PCR were performed to examine the expression and methylation. Stable clones with DLEC1 overexpression were established to analyze cell proliferation and cell cycle. RESULTS DLEC1 was silenced and hypermethylated in 9 of 11 cell lines examined. Treatment with 5-aza-2'-deoxycytidine reversed the methylation and restored DLEC1 expression. The correlation between hypermethylation and expression was also demonstrated in 10 pairs of hepatocellular carcinoma and adjacent normal tissues (t-test, p<0.05). Hypermethylation of DLEC1 was detected in 70.6% of tumors, compared to 10.3% in normal tissues (n=68, p<0.001, chi(2)). Of interest, DLEC1 methylation was associated with the AJCC staging of the tumors (p=0.036, chi(2)). DLEC1 over-expression in cell lines decreased colony formation, cell growth and cell size, and induced a G1 arrest in cell cycle. CONCLUSIONS Our data indicate that DLEC1 is a candidate tumor suppressor gene that plays an important role in the development and progression of hepatocellular carcinoma.
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Affiliation(s)
- Guo-Hua Qiu
- Department of Physiology, Faculty of Medicine, National University of Singapore, Singapore
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93
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Suzuki H, Toyota M, Carraway H, Caraway H, Gabrielson E, Ohmura T, Fujikane T, Nishikawa N, Sogabe Y, Nojima M, Sonoda T, Mori M, Hirata K, Imai K, Shinomura Y, Baylin SB, Tokino T. Frequent epigenetic inactivation of Wnt antagonist genes in breast cancer. Br J Cancer 2008; 98:1147-56. [PMID: 18283316 PMCID: PMC2275475 DOI: 10.1038/sj.bjc.6604259] [Citation(s) in RCA: 187] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Although mutation of APC or CTNNB1 (β-catenin) is rare in breast cancer, activation of Wnt signalling is nonetheless thought to play an important role in breast tumorigenesis, and epigenetic silencing of Wnt antagonist genes, including the secreted frizzled-related protein (SFRP) and Dickkopf (DKK) families, has been observed in various tumours. In breast cancer, frequent methylation and silencing of SFRP1 was recently documented; however, altered expression of other Wnt antagonist genes is largely unknown. In the present study, we found frequent methylation of SFRP family genes in breast cancer cell lines (SFRP1, 7 out of 11, 64%; SFRP2, 11 out of 11, 100%; SFRP5, 10 out of 11, 91%) and primary breast tumours (SFRP1, 31 out of 78, 40%; SFRP2, 60 out of 78, 77%; SFRP5, 55 out of 78, 71%). We also observed methylation of DKK1, although less frequently, in cell lines (3 out of 11, 27%) and primary tumours (15 out of 78, 19%). Breast cancer cell lines express various Wnt ligands, and overexpression of SFRPs inhibited cancer cell growth. In addition, overexpression of a β-catenin mutant and depletion of SFRP1 using small interfering RNA synergistically upregulated transcriptional activity of T-cell factor/lymphocyte enhancer factor. Our results confirm the frequent methylation and silencing of Wnt antagonist genes in breast cancer, and suggest that their loss of function contributes to activation of Wnt signalling in breast carcinogenesis.
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Affiliation(s)
- H Suzuki
- First Department of Internal Medicine, Sapporo Medical University, Sapporo, Japan
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94
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Jung AY, Poole EM, Bigler J, Whitton J, Potter JD, Ulrich CM. DNA methyltransferase and alcohol dehydrogenase: gene-nutrient interactions in relation to risk of colorectal polyps. Cancer Epidemiol Biomarkers Prev 2008; 17:330-8. [PMID: 18268116 DOI: 10.1158/1055-9965.epi-07-2608] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Disturbances in DNA methylation are a characteristic of colorectal carcinogenesis. Folate-mediated one-carbon metabolism is essential for providing one-carbon groups for DNA methylation via DNA methyltransferases (DNMTs). Alcohol, a folate antagonist, could adversely affect one-carbon metabolism. In a case-control study of colorectal polyps, we evaluated three single nucleotide polymorphisms (-149C>T, -283T>C, -579G>T) in the promoter region of the DNMT3b gene, and a functional polymorphism in the coding region of the alcohol dehydrogenase ADH1C gene, ADH1C *2. Cases had a first diagnosis of colorectal adenomatous (n = 530) or hyperplastic (n = 202) polyps at the time of colonoscopy, whereas controls were polyp-free (n = 649). Multivariate logistic regression analysis was used to estimate odds ratios (OR) and corresponding 95% confidence intervals (CI). There were no significant main associations between the DNMT3b or ADH1C polymorphisms and polyp risk. However, DNMT3b -149TT was associated with an increase in adenoma risk among individuals with low folate and methionine intake (OR, 2.00; 95% CI, 1.06-3.78, P interaction = 0.10). The ADH1C *2/*2 genotype was associated with a possibly elevated risk for adenomatous polyps among individuals who consumed >26 g of alcohol/d (OR, 1.95; 95% CI, 0.60-6.30), whereas individuals who were wild-type for ADH1C were not at increased risk of adenoma (P interaction = 0.01). These gene-diet interactions suggest that polymorphisms relevant to DNA methylation or alcohol metabolism may play a role in colorectal carcinogenesis in conjunction with a high-risk diet.
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Affiliation(s)
- Audrey Y Jung
- Cancer Prevention Program, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, M4-B402, Seattle, WA 98109-1024, USA
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95
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Tanaka K, Tainaka K, Umemoto T, Nomura A, Okamoto A. An osmium-DNA interstrand complex: application to facile DNA methylation analysis. J Am Chem Soc 2007; 129:14511-7. [PMID: 17963391 DOI: 10.1021/ja076140r] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Nucleic acids often acquire new functions by forming a variety of complexes with metal ions. Osmium, in an oxidized state, also reacts with C5-methylated pyrimidines. However, control of the sequence specificity of osmium complexation with DNA is still immature, and the value of the resulting complexes is unknown. We have designed a bipyridine-attached adenine derivative for sequence-specific osmium complexation. Sequence-specific osmium complexation was achieved by hybridization of a short DNA molecule containing this functional nucleotide to a target DNA sequence and resulted in the formation of a cross-linked structure. The interstrand cross-link clearly distinguished methylated cytosines from unmethylated cytosines and was used to quantify the degree of methylation at a specific cytosine in the genome.
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Affiliation(s)
- Kazuo Tanaka
- Frontier Research System, RIKEN (The Institute of Physical and Chemical Research), Wako, Saitama 351-1098, Japan
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96
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Loring GL, Christensen KC, Gerber SA, Brenner C. Yeast Chfr homologs retard cell cycle at G1 and G2/M via Ubc4 and Ubc13/Mms2-dependent ubiquitination. Cell Cycle 2007; 7:96-105. [PMID: 18202552 DOI: 10.4161/cc.7.1.5113] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Checkpoint with forkhead-associated and RING (Chfr) is a ubiquitin ligase (E3) that establishes an antephase or prometaphase checkpoint in response to mitotic stress. Though ubiquitination is essential for checkpoint function, the sites, linkages and ubiquitin conjugating enzyme (E2) specificity are controversial. Here we dissect the function of the two Chfr homologs in S. cerevisiae, Chf1 and Chf2, overexpression of which retard cell cycle at both G(1) and G(2). Using a genetic assay, we establish that Ubc4 is required for Chf2-dependent G(1) cell cycle delay and Chf protein turnover. In contrast, Ubc13/Mms2 is required for G(2) delay and does not contribute to Chf protein turnover. By reconstituting cis and trans-ubiquitination activities of Chf proteins in purified systems and characterizing sites modified and linkages formed by tandem mass spectrometry, we discovered that Ubc13/Mms2- dependent modifications are a distinct subset of those catalyzed by Ubc4. Mutagenesis of Lys residues identified in vitro indicates that site-specific Ubc4-dependent Chf protein autoubiquitination is responsible for Chf protein turnover. Thus, combined genetic and biochemical analyses indicate that Chf proteins have dual E2 specificity accounting for different functions in the cell cycle.
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Affiliation(s)
- Greta L Loring
- Department of Genetics and Norris Cotton Cancer Center, Dartmouth Medical School, Lebanon, New Hampshire 03756, USA
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97
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Watanabe Y, Toyota M, Kondo Y, Suzuki H, Imai T, Ohe-Toyota M, Maruyama R, Nojima M, Sasaki Y, Sekido Y, Hiratsuka H, Shinomura Y, Imai K, Itoh F, Tokino T. PRDM5 identified as a target of epigenetic silencing in colorectal and gastric cancer. Clin Cancer Res 2007; 13:4786-94. [PMID: 17699856 DOI: 10.1158/1078-0432.ccr-07-0305] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
PURPOSE PR (PRDI-BF1 and RIZ) domain proteins (PRDM) are a subfamily of the kruppel-like zinc finger gene products that play key roles during cell differentiation and malignant transformation. The aim of the present study was to begin to examine the involvement of epigenetic alteration of PRDM expression in gastric and colorectal cancer. EXPERIMENTAL DESIGN We used real-time PCR to assess expression of PRDM1-17. In addition, we used bisulfite PCR to assess DNA methylation and chromatin immunoprecipitation to assess histone modification in colorectal and gastric cancer cell lines lacking PRDM5 expression. RESULTS Among the 17 PRDM family genes tested, we found that PRDM5 is the most frequently silenced in colorectal and gastric cancer cell lines. Silencing of PRDM5 was mediated by either DNA methylation or trimethylation of Lys(27) of histone H3. Introduction of PRDM5 into cancer cells suppressed cell growth, suggesting that it acts as a tumor suppressor in gastrointestinal cancers. Methylation of PRDM5 was detected in 6.6% (4 of 61) of primary colorectal and 50.0% (39 of 78) of primary gastric cancers but not in noncancerous tissue samples collected from areas adjacent to the tumors. CONCLUSIONS Our data suggest that epigenetic alteration of PRDM5 (e.g., methylation of its 5'-CpG island or trimethylation of Lys(27) of histone H3) likely plays a key role in the progression of gastrointestinal cancers and may be a useful molecular marker.
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Affiliation(s)
- Yoshiyuki Watanabe
- Department of Molecular Biology, Cancer Research Institute, Sapporo Medical University, Sapporo, Japan
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98
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Sato H, Suzuki H, Toyota M, Nojima M, Maruyama R, Sasaki S, Takagi H, Sogabe Y, Sasaki Y, Idogawa M, Sonoda T, Mori M, Imai K, Tokino T, Shinomura Y. Frequent epigenetic inactivation of DICKKOPF family genes in human gastrointestinal tumors. Carcinogenesis 2007; 28:2459-66. [PMID: 17675336 DOI: 10.1093/carcin/bgm178] [Citation(s) in RCA: 166] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Activation of Wnt signaling has been implicated in tumorigenesis, and epigenetic silencing of Wnt antagonist genes has been detected in various cancers. In the present study, we examined the expression and methylation of DICKKOPF (DKK) family genes in gastrointestinal cancer cell lines. We found that all known DKK genes were frequently silenced in colorectal cancer (CRC) cells (DKK1, 3/9, 33%; DKK2, 8/9, 89%; DKK3, 5/9, 56% and DKK4, 5/9, 56%), but not in normal colon mucosa. DKK1, -2 and -3 have 5' CpG islands, and show an inverse relation between expression and methylation. DKK methylation also was frequently observed in gastric cancer (GC) cell lines (DKK1, 6/16, 38%; DKK2, 15/16, 94% and DKK3, 10/16, 63%), but was seen less frequently in hepatocellular carcinoma and pancreatic cancer cell lines. DKKs also were frequently methylated in primary CRCs (DKK1, 7/58, 12%; DKK2, 45/58, 78% and DKK3, 12/58, 21%) and GCs (DKK1, 15/31, 48%; DKK2, 26/31, 84% and DKK3, 12/31, 39%). Against a background of CTNNB1 or APC mutations, Dickkopfs (Dkks) were less effective inhibitors of Wnt signaling than secreted frizzled-related proteins, though over-expression of Dkks suppressed colony formation of CRC cells with such mutations. Our results demonstrate that DKKs are frequent targets of epigenetic silencing in gastrointestinal tumors, and that loss of DKKs may facilitate tumorigenesis through beta-catenin/T-cell factor-independent mechanisms.
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Affiliation(s)
- Hironobu Sato
- First Department of Internal Medicine, Sapporo Medical University, Sapporo 060-8543, Japan
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99
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Schuebel KE, Chen W, Cope L, Glöckner SC, Suzuki H, Yi JM, Chan TA, Neste LV, Criekinge WV, van den Bosch S, van Engeland M, Ting AH, Jair K, Yu W, Toyota M, Imai K, Ahuja N, Herman JG, Baylin SB. Comparing the DNA hypermethylome with gene mutations in human colorectal cancer. PLoS Genet 2007; 3:1709-23. [PMID: 17892325 PMCID: PMC1988850 DOI: 10.1371/journal.pgen.0030157] [Citation(s) in RCA: 262] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2007] [Accepted: 07/31/2007] [Indexed: 11/18/2022] Open
Abstract
We have developed a transcriptome-wide approach to identify genes affected by promoter CpG island DNA hypermethylation and transcriptional silencing in colorectal cancer. By screening cell lines and validating tumor-specific hypermethylation in a panel of primary human colorectal cancer samples, we estimate that nearly 5% or more of all known genes may be promoter methylated in an individual tumor. When directly compared to gene mutations, we find larger numbers of genes hypermethylated in individual tumors, and a higher frequency of hypermethylation within individual genes harboring either genetic or epigenetic changes. Thus, to enumerate the full spectrum of alterations in the human cancer genome, and to facilitate the most efficacious grouping of tumors to identify cancer biomarkers and tailor therapeutic approaches, both genetic and epigenetic screens should be undertaken. Loss of gene expression in association with aberrant accumulation of 5-methylcytosine in gene promoter CpG islands is a common feature of human cancer. Here, we describe a method to discover these genes that permits identification of hundreds of novel candidate cancer genes in any cancer cell line. We now estimate that as much as 5% of colon cancer genes may harbor aberrant gene hypermethylation and we term these the cancer “promoter CpG island DNA hypermethylome.” Multiple mutated genes recently identified via cancer resequencing efforts are shown to be within this hypermethylome and to be more likely to undergo epigenetic inactivation than genetic alteration. Our approach allows derivation of new potential tumor biomarkers and potential pathways for therapeutic intervention. Importantly, our findings illustrate that efforts aimed at complete identification of the human cancer genome should include analyses of epigenetic, as well as genetic, changes.
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Affiliation(s)
- Kornel E Schuebel
- Cancer Biology Division, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland, United States of America
- * To whom correspondence should be addressed. E-mail: (KES); (SBB)
| | - Wei Chen
- Cancer Biology Division, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland, United States of America
- Predoctoral Training Program in Human Genetics, The Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Leslie Cope
- Biometry and Clinical Trials Division, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland, United States of America
| | - Sabine C Glöckner
- Department of Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Hiromu Suzuki
- First Department of Internal Medicine, Sapporo Medical University, Sapporo, Japan
| | - Joo-Mi Yi
- Cancer Biology Division, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland, United States of America
| | - Timothy A Chan
- Cancer Biology Division, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland, United States of America
| | - Leander Van Neste
- Department of Molecular Biotechnology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | | | | | - Manon van Engeland
- Department of Pathology, University of Maastricht, Maastricht, The Netherlands
| | - Angela H Ting
- Cancer Biology Division, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland, United States of America
| | - Kamwing Jair
- Bionumerik Pharmaceuticals Inc., San Antonio, Texas, United States of America
| | - Wayne Yu
- Cancer Biology Division, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland, United States of America
| | - Minoru Toyota
- First Department of Internal Medicine, Sapporo Medical University, Sapporo, Japan
| | - Kohzoh Imai
- First Department of Internal Medicine, Sapporo Medical University, Sapporo, Japan
| | - Nita Ahuja
- Department of Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - James G Herman
- Cancer Biology Division, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland, United States of America
| | - Stephen B Baylin
- Cancer Biology Division, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland, United States of America
- Predoctoral Training Program in Human Genetics, The Johns Hopkins University, Baltimore, Maryland, United States of America
- * To whom correspondence should be addressed. E-mail: (KES); (SBB)
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100
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Ludwig AH, Bujko M, Bidzinski M, Kupryjańczyk J. CHFR gene is neither mutated nor hypermethylated in ovarian cancer. ACTA ACUST UNITED AC 2007; 31:257-61. [PMID: 17673375 DOI: 10.1016/j.cdp.2006.04.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/22/2006] [Indexed: 10/23/2022]
Abstract
BACKGROUND CHFR is a mitotic checkpoint protein that under mitotic stress (caused also by taxanes) delays progression into mitosis. METHODS We looked for CHFR gene (605,209) alterations and its promoter hypermethylation in 48 ovarian carcinomas either sensitive or resistant to taxane treatment. We used single-strand conformation polymorphism analysis, sequencing and methylation-specific polymerase chain reaction. RESULTS Neither mutations in the CHFR gene nor hypermethylation of its promoter region were found. A novel single nucleotide polymorphism (Val154Val) was identified in exon 5 of alternatively spliced transcript. CONCLUSIONS Our results indicate that CHFR gene status cannot serve as a molecular predictor of ovarian cancer sensitivity to taxanes.
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Affiliation(s)
- Agnieszka H Ludwig
- Department of Molecular Pathology, The Maria Sklodowska-Curie Memorial Cancer Center, Institute of Oncology, Roentgena 5, 02-781 Warsaw, Poland
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