101
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Rauch T, Li H, Wu X, Pfeifer GP. MIRA-assisted microarray analysis, a new technology for the determination of DNA methylation patterns, identifies frequent methylation of homeodomain-containing genes in lung cancer cells. Cancer Res 2007; 66:7939-47. [PMID: 16912168 DOI: 10.1158/0008-5472.can-06-1888] [Citation(s) in RCA: 212] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We present a straightforward and comprehensive approach for DNA methylation analysis in mammalian genomes. The methylated-CpG island recovery assay (MIRA), which is based on the high affinity of the MBD2/MBD3L1 complex for methylated DNA, has been used to detect cell type-dependent differences in DNA methylation on a microarray platform. The procedure has been verified and applied to identify a series of novel candidate lung tumor suppressor genes and potential DNA methylation markers that contain methylated CpG islands. One gene of particular interest was DLEC1, located at a commonly deleted area on chromosome 3p22-p21.3, which was frequently methylated in primary lung cancers and melanomas. Among the identified methylated genes, homeodomain-containing genes were unusually frequent (11 of the top 50 hits) and were targeted on different chromosomes. These genes included LHX2, LHX4, PAX7, HOXB13, LBX1, SIX2, HOXD3, DLX1, HOXD1, ONECUT2, and PAX9. The data show that MIRA-assisted microarray analysis has a low false-positive rate and has the capacity to catalogue methylated CpG islands on a genome-wide basis. The results support the hypothesis that cancer-associated DNA methylation events do not occur randomly throughout the genome but at least some are targeted by specific mechanisms.
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Affiliation(s)
- Tibor Rauch
- Division of Biology, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
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102
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Lin RK, Hsu CH, Wang YC. Mithramycin A inhibits DNA methyltransferase and metastasis potential of lung cancer cells. Anticancer Drugs 2007; 18:1157-64. [PMID: 17893516 DOI: 10.1097/cad.0b013e3282a215e9] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Abnormal CpG island hypermethylation of multiple tumor-suppressor genes (TSGs) can lead to the initiation and progression of human cancer. The cytosine of the CpG island on the promoter region is methylated by 5'-cytosine-methyltransferases (DNMTs). Pharmacologic inhibitors of CpG island methylation provide a rational approach to reactivate the TSGs in tumor cells and to restore the critical cellular pathways in cancer cells. Mithramycin A (MMA) is known to be a GC- and CG-rich DNA-binding agent. We sought to determine whether MMA could inhibit CpG island methylation and DNMT expression in lung cancer cells. We found that MMA reduced the CpG island methylation of antimetastasis TSGs, including SLIT2 and TIMP-3 genes, and was associated with the prevention of metastasis. When highly metastatic CL1-5 lung cancer cells were treated with low doses (10 nmol/l) of MMA for 14 days, they reexpressed mRNA levels for these genes. MMA also inhibited the invasion phenotypes of CL1-5 cells as indicated by its inhibition of cancer cell migration using wound-healing and transwell assays. Molecular docking of MMA onto the DNMT1 catalytic domain revealed that MMA might interact with the catalytic pocket of DNMT1. Western blots showed that DNMT1 protein levels were depleted after MMA. These data support the idea that MMA has demethylation and antimetastasis effects on lung cancer cells. This mechanism might be mediated by the interaction of MMA and DNMT1, leading to the depletion of the DNMT1 protein and the reversal of the metastasis phenotype in lung cancer cells.
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Affiliation(s)
- Ruo-Kai Lin
- Department of Life Sciences, National Taiwan Normal University, Taipei, Taiwan, ROC
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103
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Arachidonic acid pathway activates multidrug resistance related protein in cultured human lung cells. Arch Toxicol 2007; 82:323-32. [PMID: 17943274 DOI: 10.1007/s00204-007-0251-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2007] [Accepted: 09/26/2007] [Indexed: 02/04/2023]
Abstract
Primary cultures of human lung cells can serve as a model system to study the mechanisms underlying the effects of irritants in air and to get a deeper insight into the (patho)physiological roles of the xenobiotic detoxification systems. For 99 human lung cancer cases the culture duration for bronchial epithelium and peripheral lung cells (PLC) are given in term of generations and weeks. Using this system, we investigated whether and how prostaglandins (PG) modify multidrug resistance related protein (MRP) function in normal human lung cells. PGF2alpha had no effect on MRP function, whereas PGE2 induced MRP activity in cultured NHBECs. The transport activity study of MRP in NHBEC, PLC, and A549 under the effect of exogenously supplied PGF2alpha (10 microM, 1 day) using single cell fluorimetry revealed no alteration in transport activity of MRP. PG concentrations were within the physiological range. COX I and II inhibitors indomethacin (5, 10 microM) and celecoxib (5, 10 microM) could substantially decrease the transport activity of MRP in NHBEC, PLC, and A549 in 1- and 4-day trials. Prostaglandin E2 did not change cadmium-induced caspase 3/7 activation in NHBECs and had no own effect on caspase 3/7 activity. Cadmium chloride (5, 10 microM) was an effective inducer of caspase 3/7 activation in NHBECs with a fivefold and ninefold rise of activity. In primary human lung cells arachidonic acid activates MRP transport function only in primary epithelial lung cells by prostaglandin E2 but not by F2alpha mediated pathways and this effect needs some time to develop.
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104
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Yue W, Dacic S, Sun Q, Landreneau R, Guo M, Zhou W, Siegfried JM, Yu J, Zhang L. Frequent inactivation of RAMP2, EFEMP1 and Dutt1 in lung cancer by promoter hypermethylation. Clin Cancer Res 2007; 13:4336-44. [PMID: 17671114 DOI: 10.1158/1078-0432.ccr-07-0015] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE The goal of this study is to identify novel genes frequently silenced by promoter hypermethylation in lung cancer. EXPERIMENTAL DESIGNS Bioinformatic analysis was done to identify candidate genes significantly down-regulated in lung cancer. The effects of DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine on the expression of the candidate genes were determined. Methylated CpG sites in the promoters of the candidate genes were identified using bisulfite DNA sequencing. Methylation-specific PCR was developed and used to analyze DNA methylation in cell lines and clinical specimen. Pathologic and functional analyses were done to study the role of one candidate gene, receptor activity-modifying protein 2 (RAMP2), in suppressing lung cancer cell growth. RESULTS Among 54 candidate genes down-regulated in lung cancer, 31 were found to contain CpG islands in their promoters. Six of these 31 genes could be reactivated by 5-aza-2'-deoxycytidine in at least four of six lung cancer cell lines analyzed. Promoter hypermethylation of RAMP2, epidermal growth factor-containing fibulin-like extracellular matrix protein 1, and deleted in U Twenty Twenty cells was detected in 36% to 77% of 22 lung cancer cell lines and in 38% to 50% of 32 primary lung tumors, whereas hypermethylathion of these genes was rarely found in the matched normal samples. The methylation frequencies of these genes in lung cancer were similar to those of commonly used methylation markers, such as RAS association domain family protein 1A, p16, and methylguanine-DNA methyltransferase. Immunohistochemistry showed that RAMP2 was down-regulated in a majority of lung tumors, and RAMP2 down-regulation was correlated with high tumor grade. Ectopic expression of RAMP2 inhibited lung cancer cell growth and caused apoptotic cell death. Knockdown of RAMP2 by RNA interference stimulated cell proliferation. CONCLUSIONS Studying the newly identified genes may provide new insight into lung tumorigenesis. These genes might be useful as molecular markers of lung cancer.
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MESH Headings
- Adenocarcinoma/genetics
- Adenocarcinoma/pathology
- Antimetabolites, Antineoplastic/pharmacology
- Azacitidine/pharmacology
- Carcinoma, Non-Small-Cell Lung/genetics
- Carcinoma, Non-Small-Cell Lung/pathology
- CpG Islands
- DNA Methylation
- DNA Mutational Analysis
- DNA, Neoplasm/genetics
- Down-Regulation
- Epigenesis, Genetic
- Extracellular Matrix Proteins/antagonists & inhibitors
- Extracellular Matrix Proteins/genetics
- Extracellular Matrix Proteins/metabolism
- Gene Expression Regulation, Neoplastic
- Gene Silencing
- Humans
- Immunoenzyme Techniques
- Intracellular Signaling Peptides and Proteins/antagonists & inhibitors
- Intracellular Signaling Peptides and Proteins/genetics
- Intracellular Signaling Peptides and Proteins/metabolism
- Lung Neoplasms/genetics
- Lung Neoplasms/pathology
- Membrane Proteins/antagonists & inhibitors
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Nerve Tissue Proteins/antagonists & inhibitors
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Promoter Regions, Genetic/genetics
- Receptor Activity-Modifying Protein 2
- Receptor Activity-Modifying Proteins
- Receptors, Immunologic/antagonists & inhibitors
- Receptors, Immunologic/genetics
- Receptors, Immunologic/metabolism
- Tumor Cells, Cultured
- Roundabout Proteins
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Affiliation(s)
- Wen Yue
- Department of Pharmacology, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA
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105
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Gery S, Komatsu N, Kawamata N, Miller CW, Desmond J, Virk RK, Marchevsky A, Mckenna R, Taguchi H, Koeffler HP. Epigenetic silencing of the candidate tumor suppressor gene Per1 in non-small cell lung cancer. Clin Cancer Res 2007; 13:1399-404. [PMID: 17332281 DOI: 10.1158/1078-0432.ccr-06-1730] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Epigenetic events are a critical factor contributing to cancer development. The purpose of this study was to identify tumor suppressor genes silenced by DNA methylation and histone deacetylation in non-small cell lung cancer (NSCLC). EXPERIMENTAL DESIGN We used microarray analysis to screen for tumor suppressor genes. RESULTS We identified Per1, a core circadian gene, as a candidate tumor suppressor in lung cancer. Although Per1 levels were high in normal lung, its expression was low in a large panel of NSCLC patient samples and cell lines. Forced expression of Per1 in NSCLC cell lines led to significant growth reduction and loss of clonogenic survival. Recent studies showed that epigenetic regulation, particularly histone H3 acetylation, is essential for circadian function. Using bisulfite sequencing and chromatin immunoprecipitation, we found that DNA hypermethylation and histone H3 acetylation are potential mechanisms for silencing Per1 expression NSCLC. CONCLUSIONS These results support the hypothesis that disruption of circadian rhythms plays an important role in lung tumorigenesis. Moreover, our findings suggest a novel link between circadian epigenetic regulation and cancer development.
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Affiliation(s)
- Sigal Gery
- Division of Hematology/Oncology, Cedars-Sinai Medical Center, University of California, Los Angeles School of Medicine, Los Angeles, California 90048, USA.
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106
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Karamouzis MV, Konstantinopoulos PA, Papavassiliou AG. Epigenomics in respiratory epithelium carcinogenesis: prevention and therapeutic challenges. Cancer Treat Rev 2007; 33:284-8. [PMID: 17367937 DOI: 10.1016/j.ctrv.2007.01.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2006] [Revised: 01/08/2007] [Accepted: 01/09/2007] [Indexed: 11/19/2022]
Abstract
Respiratory epithelium carcinogenesis is currently considered as the phenotypic aspect of serial genetic and epigenetic aberrations resulting in deregulation of cellular homeostasis. Recent data indicate that DNA demethylating agents and histone deacetylase inhibitors might act synergistically for the prevention of cancer development throughout the carcinogen-exposed epithelium. Preliminary clinical trials have shown encouraging results using these new molecules in lung carcinomas therapeutics. However, the caveats that should be overtaken for efficacious antitumour activity have also emerged. Setting the context in which epigenetic modifications contribute to carcinogenesis evolution is of paramount importance in order to optimize the potency of the current and future epigenome targeting agents.
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Affiliation(s)
- Michalis V Karamouzis
- Department of Biological Chemistry, Medical School, University of Athens, Athens, Greece
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107
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Bogaczewicz J, Jasielski P, Mosiewicz A, Trojanowski T, Suchozebrska-Jesionek D, Stryjecka-Zimmer M. [The role of matrix metalloproteinases and tissue inhibitors of metalloproteinases in invasion of tumours of neuroepithelial tissue]. Neurol Neurochir Pol 2007; 45:291-338. [PMID: 17103354 DOI: 10.1080/10408360801973244] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Tumour invasion requires degradation of extracellular matrix components and migration of cells through degraded structures into surrounding tissues. Matrix metalloproteinases (MMP) constitute a family of zinc and calcium-dependent endopeptidases that play a key role in the breakdown of extracellular matrix, and in processing of cytokines, growth factors, chemokines and cell surface receptors. Their activity is regulated at the levels of transcription, activation and inhibition by tissue inhibitors of metalloproteinases (TIMP). Changes in expression of MMP and TIMP are implicated in tumour invasion, because they may contribute to both migration of tumour cells and angiogenesis. Alterations of MMP expression observed in brain tumours arouse interest in the development and evaluation of synthetic matrix metalloproteinase inhibitors as antitumour agents.
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Affiliation(s)
- Jarosław Bogaczewicz
- Katedra i Klinika Neurochirurgii i Neurochirurgii Dzieciêcej, Akademia Medyczna im. prof. Feliksa Skubiszewskiego, ul. Jaczewskiego 8, 20-954 Lublin.
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108
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Abstract
Transcription factor AP-1 is a dimer complex composed by DNA-binding proteins of Jun, Fos, and ATF families. AP-1 mediates cell response on growth factors, cytokines, neurotransmitters and other intercellular signaling molecules. AP-1 activity is mediated by G-proteins, adapter proteins, MAP kinases and other elements of cellular signaling systems. AP-1 dependent genes play a pivotal role in regulation of cell proliferation, morphogenesis, apoptosis, and differentiation.
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109
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Cantor JP, Iliopoulos D, Rao AS, Druck T, Semba S, Han SY, McCorkell KA, Lakshman TV, Collins JE, Wachsberger P, Friedberg JS, Huebner K. Epigenetic modulation of endogenous tumor suppressor expression in lung cancer xenografts suppresses tumorigenicity. Int J Cancer 2007; 120:24-31. [PMID: 17019711 DOI: 10.1002/ijc.22073] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Epigenetic changes involved in cancer development, unlike genetic changes, are reversible. DNA methyltransferase and histone deacetylase inhibitors show antiproliferative effects in vitro, through tumor suppressor reactivation and induction of apoptosis. Such inhibitors have shown activity in the treatment of hematologic disorders but there is little data concerning their effectiveness in treatment of solid tumors. FHIT, WWOX and other tumor suppressor genes are frequently epigenetically inactivated in lung cancers. Lung cancer cell clones carrying conditional FHIT or WWOX transgenes showed significant suppression of xenograft tumor growth after induction of expression of the FHIT or WWOX transgene, suggesting that treatments to restore endogenous Fhit and Wwox expression in lung cancers would result in decreased tumorigenicity. H1299 lung cancer cells, lacking Fhit, Wwox, p16(INK4a) and Rassf1a expression due to epigenetic modifications, were used to assess efficacy of epigenetically targeted protocols in suppressing growth of lung tumors, by injection of 5-aza-2-deoxycytidine (AZA) and trichostatin A (TSA) in nude mice with established H1299 tumors. High doses of intraperitoneal AZA/TSA suppressed growth of small tumors but did not affect large tumors (200 mm(3)); lower AZA doses, administered intraperitoneally or intratumorally, suppressed growth of small tumors without apparent toxicity. Responding tumors showed restoration of Fhit, Wwox, p16(INKa), Rassf1a expression, low mitotic activity, high apoptotic fraction and activation of caspase 3. These preclinical studies show the therapeutic potential of restoration of tumor suppressor expression through epigenetic modulation and the promise of re-expressed tumor suppressors as markers and effectors of the responses.
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Affiliation(s)
- Joshua P Cantor
- Department of Surgery, University of Pennsylvania, Philadelphia, PA, USA
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110
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Hoebeeck J, Michels E, Menten B, Van Roy N, Eggert A, Schramm A, De Preter K, Yigit N, De Smet E, De Paepe A, Laureys G, Vandesompele J, Speleman F. High resolution tiling-path BAC array deletion mapping suggests commonly involved 3p21-p22 tumor suppressor genes in neuroblastoma and more frequent tumors. Int J Cancer 2007; 120:533-8. [PMID: 17096344 DOI: 10.1002/ijc.22326] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The recurrent loss of 3p segments in neuroblastoma suggests the implication of 1 or more tumor suppressor genes but thus far few efforts have been made to pinpoint their detailed chromosomal position. To achieve this goal, array-based comparative genomic hybridization was performed on a panel of 23 neuroblastoma cell lines and 75 primary tumors using a tiling-path bacterial artificial chromosome array for chromosome 3p. A total of 45 chromosome 3 losses were detected, including whole chromosome losses, large terminal deletions and interstitial deletions. The latter, observed in cell lines as well as a number of distal deletions detected in primary tumors, allowed us to demarcate 3 minimal regions of loss of 3.6 Mb [3p21.31-p21.2, shortest regions of overlap (SRO)1], 1.4 Mb (3p22.3-3p22.2, SRO2) and 3.8 Mb (3p25.3-p25.1, SRO3) in size. The present data significantly extend previous findings and now firmly establish critical regions on 3p implicated in neuroblastoma. Interestingly, the 2 proximal regions coincide with previously defined SROs on 3p21.3 in more frequent tumors including lung and breast cancer. As such, similar tumor suppressor genes may play a critical role in development or progression of a variety of neoplasms, including neuroblastoma.
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Affiliation(s)
- Jasmien Hoebeeck
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
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111
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Fernández-Figueras MT, Puig L, Musulén E, Gilaberte M, Lerma E, Serrano S, Ferrándiz C, Ariza A. Expression profiles associated with aggressive behavior in Merkel cell carcinoma. Mod Pathol 2007; 20:90-101. [PMID: 17115023 DOI: 10.1038/modpathol.3800717] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Primary neuroendocrine carcinoma of the skin, or Merkel cell carcinoma, is the most aggressive cutaneous neoplasm. In spite of its similarities to small cell carcinomas from other locations, Merkel cell carcinoma shows many peculiarities probably related to its epidermal origin and the etiologic role of UV radiation. We have immunohistochemically investigated 43 markers on a tissue microarray in which 31 surgically resected Merkel cell carcinomas were represented. Of these, 15 patients remained free of disease after removal, whereas 16 developed metastases. Immunoreactivity was scored according to staining intensity and the percentage of positive cells. We found statistically significant correlations between metastatic tumor spread and overexpression of matrix metalloproteinase (MMP) 7, MMP10/2, tissue inhibitor of metalloproteinase 3, vascular endothelial growth factor (VEGF), P38, stromal NF-kappaB, and synaptophysin. Also detected were statistically significant correlations between the expression levels of MMP7 and VEGF, MMP7 and P21, MMP7 and P38, MMP10/2 and VEGF, P38 and synaptophysin, P38 and P53, and P21 and stromal NF-kappaB. These findings may be helpful in predicting the clinical course of Merkel cell carcinoma and are potentially useful for the development of targeted therapies.
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112
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Sato S, Hokazono K, Irie T, Ueki T, Waki M, Nojima T, Kondo H, Takenaka S. Ferrocenylnaphthalene diimide-based electrochemical detection of methylated gene. Anal Chim Acta 2006; 578:82-7. [PMID: 17723697 DOI: 10.1016/j.aca.2006.04.056] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2006] [Revised: 04/13/2006] [Accepted: 04/20/2006] [Indexed: 11/21/2022]
Abstract
Ferrocenylnaphthalene diimide (FND)-based electrochemical hybridization assay was applied to the detection of methylated cytosine of DNA using the products obtained after treatment with bisulfite followed by polymerase chain reaction (PCR), where unmethylated cytosine is converted to thymine and methylated one to cytosine. Twenty-meric DNA probes for the methylated (cytosine) and unmethylated (thymine) types of the part of the promoter region of cyclin D-dependent protein kinase inhibitor, p16, gene (p16(Ink4a)) were used to be immobilized on the electrochemical array (ECA) chip. Using 1 microL of 10 ng/microL of methylated sample obtained from the methylation-specific PCR of methylated genome containing 10-times excess of unmethylated one, the methylated PCR sample could be detected by the identical electrochemical signals from the two DNA probes under the settled optimum hybridization conditions.
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Affiliation(s)
- Shinobu Sato
- Department of Biochemical Engineering and Science, Kyushu Institute of Technology, Iizuka 820-8502, Japan
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113
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Ohtsubo K, Watanabe H, Yao F, Okada G, Mouri H, Yamaguchi Y, Sawabu N. Preproenkephalin hypermethylation in the pure pancreatic juice compared with p53 mutation in the diagnosis of pancreatic carcinoma. J Gastroenterol 2006; 41:791-7. [PMID: 16988769 DOI: 10.1007/s00535-006-1857-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2006] [Accepted: 05/22/2006] [Indexed: 02/04/2023]
Abstract
BACKGROUND Aberrant methylation of CpG islands is a common mechanism for the dysregulation of tumor suppressor genes in a variety of human malignancies. Preproenkephalin ppENK) hypermethylation is recognized in 90% of pancreatic carcinoma (PCa) tissues, but not in normal pancreas. We analyzed ppENK hypermethylation in pure pancreatic juice (PPJ) in patients with PCa, intraductal papillary mucinous neoplasms (IPMN), and chronic pancreatitis (CP), and elucidated its usefulness as a marker in the diagnosis of PCa compared with p53 mutation. METHODS PPJ was collected endoscopically from 28 patients with PCa, 15 patients with IPMN, and 20 patients with CP. DNA was extracted from the supernatant and the sediment of PPJ. Methylation-specific polymerase chain reaction was performed for hypermethylation analysis of ppENK. In addition, single-strand conformation polymorphism and direct sequencing were performed simultaneously to identify p53 mutations. RESULTS The incidence of ppENK hypermethylation in the supernatant and/or the sediment of PPJ was 50% (14 of 28) in patients with PCa. In contrast, the incidence of ppENK hypermethylation was 26.7% (4 of 15) in patients with IPMN, and 5% (1 of 20) in patients with CP (P < 0.002). The incidence of p53 mutations in the PPJ was 42.9% (12 of 28) in patients with PCa and 0% (0 of 20) in patients with CP. Furthermore, the incidence of ppENK hypermethylation and/or p53 mutations in the PPJ was enhanced to 67.9% (19 of 28) in patients with PCa in the combination assay. CONCLUSIONS These results suggest that ppENK hypermethylation in PPJ is specific for cancer, and the combination assay with p53 enhances the genetic diagnosis of PCa.
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Affiliation(s)
- Koushiro Ohtsubo
- Department of Internal Medicine and Medical Oncology, Cancer Research Institute, Kanazawa University, 13-1 Takara-machi, Kanazawa 920-0934, Japan
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114
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Guan M, Zhou X, Soulitzis N, Spandidos DA, Popescu NC. Aberrant methylation and deacetylation of deleted in liver cancer-1 gene in prostate cancer: potential clinical applications. Clin Cancer Res 2006; 12:1412-9. [PMID: 16533763 DOI: 10.1158/1078-0432.ccr-05-1906] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE The deleted in liver cancer-1 (DLC-1) gene that encodes a Rho GTPase-activating protein with tumor suppressor function is located on chromosome 8p21-22, a region frequently deleted in prostate carcinomas. This study was designed to determine whether DLC-1 is deregulated in prostate carcinomas and to assess the contribution of DLC-1 alterations to prostate carcinogenesis. EXPERIMENTAL DESIGN Primary prostate carcinomas, prostate carcinoma cell lines, benign prostatic hyperplasias, and normal prostatic tissues were examined for detection of functional and structural alterations of the DLC-1 gene by real-time PCR, methylation-specific PCR, and Southern and Western blots. RESULTS Down-regulation or loss of DCL-1 mRNA expression was detected in 10 of 27 (37%) prostate carcinomas, 3 of 5 (60%) prostate carcinoma cell lines, and 5 of 21 (24%) benign prostatic hyperplasias. DLC-1 promoter methylation was identified in 13 of 27 (48%) prostate carcinomas and 2 matching normal tissues and in 15 of 21 (71%) benign prostatic hyperplasias but was absent in 10 normal prostatic tissues from noncancerous individuals. Genomic deletions were found in only 3 prostate carcinomas and 1 benign prostatic hyperplasia. DLC-1 protein was not detected in 8 of 27 (30%) prostate carcinomas and 11 of 21 (52%) benign prostatic hyperplasias. Methylation of DLC-1 correlated with age in prostate carcinoma patients (P = 0.006) and with prostate-specific antigen blood levels in benign prostatic hyperplasia patients (P = 0.029). Treatment of the three prostate carcinoma cell lines (PC-3, LNCaP, and 22Rv1) expressing a low level of DLC-1 transcripts with inhibitors of DNA methyltransferase or histone deacetylase increased DLC-1 expression. CONCLUSIONS These results show that the transcriptional silencing of DLC-1 by two epigenetic mechanisms is common and may be involved in the pathogenesis of prostate carcinomas and benign prostatic hyperplasias and could have potential clinical application in the early detection and gene therapy of prostate cancer.
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Affiliation(s)
- Ming Guan
- Laboratory of Experimental Carcinogenesis, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892-4262, USA
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115
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Peng D, Ren CP, Yi HM, Zhou L, Yang XY, Li H, Yao KT. Genetic and epigenetic alterations of DLC-1, a candidate tumor suppressor gene, in nasopharyngeal carcinoma. Acta Biochim Biophys Sin (Shanghai) 2006; 38:349-55. [PMID: 16680376 DOI: 10.1111/j.1745-7270.2006.00164.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The DLC-1 gene, located at the human chromosome region 8p22, behaves like a tumor suppressor gene and is frequently deleted in diverse tumors. The deletion of 8p22 is not an uncommon event in nasopharyngeal carcinoma (NPC), therefore we explored the expression levels of the DLC-1 gene in NPCs and NPC cell lines by reverse transcription-polymerase chain reaction. The results showed the mRNA level of DLC-1 was downregulated. To identify the mechanism of DLC-1 downregulation in NPC, we investigated the methylation status of the DLC-1 gene using methylation-specific PCR, and found that 79% (31 of 39) of the NPC tissues and two DLC-1 nonexpressing NPC cell lines, 6-10B and 5-8F, were methylated in the DLC-1 CpG island. Microsatellite PCR was also carried out, and loss of heterozygosity was found at four microsatellite sites (D8S552, D8S1754, D8S1790 and D8S549) covering the whole DLC-1 gene with ratios of 33% (4 of 12 informative cases), 18% (2 of 11), 5% (1 of 18), and 25% (3 of 12), respectively. Taken together, our results suggest that DLC-1 might be an NPC-related tumor suppressor gene affected by aberrant promoter methylation and gene deletion.
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Affiliation(s)
- Dan Peng
- Cancer Research Institute, Xiangya School of Medicine, Central South University, Changsha 410078, China
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