Methylation mediated silencing of TMS1/ASCgene in prostate cancer

Das, Ramachandran Kavitha, Vanwert Jane, Ferdinand Larry, Gopisetty Gopal, Reis, Singal, Singal Rakesh

Description

Transcriptional silencing associated with aberrant promoter methylation has been established as an alternate pathway for the development of cancer by inactivating tumor suppressor genes. TMS1 (Target of Methylation induced Silencing), also known as ASC (Apoptosis Speck like protein containing a CARD) is a tumor suppressor gene which encodes for a CARD (caspase recruitment domain) containing regulatory protein and has been shown to promote apoptosis directly and by activation of downstream caspases. This study describes the methylation induced silencing of TMS1/ASC gene in prostate cancer cell lines. We also examined the prevalence of TMS1/ASC gene methylation in prostate cancer tissue samples in an effort to correlate race and clinico-pathological features with TMS1/ASC gene methylation. Results Loss of TMS1/ASC gene expression associated with complete methylation of the promoter region was observed in LNCaP cells. Gene expression was restored by a demethylating agent, 5-aza-2'deoxycytidine, but not by a histone deacetylase inhibitor, Trichostatin A. Chromatin Immunoprecipitation (ChIP) assay showed enrichment of MBD3 (methyl binding domain protein 3) to a higher degree than commonly associated MBDs and MeCP2. We evaluated the methylation pattern in 66 prostate cancer and 34 benign prostatic hyperplasia tissue samples. TMS1/ASC gene methylation was more prevalent in prostate cancer cases than controls in White patients (OR 7.6, p 0.002) while no difference between the cases and controls was seen in Black patients (OR 1.1, p 0.91). Conclusion Our study demonstrates that methylation-mediated silencing of TMS1/ASC is a frequent event in prostate cancer, thus identifying a new potential diagnostic and prognostic marker for the treatment of the disease. Racial differences in TMS1/ASC methylation patterns implicate the probable role of molecular markers in determining in susceptibility to prostate cancer in different ethnic groups.

Informations

• Publié par: biomed
• Publié le: 01 janvier 2006
• Nombre de lectures: 10
• Langue: English

Extrait

Molecular Cancer

BioMedCentral

Open Access Research Methylation mediated silencing ofTMS1/ASCgene in prostate cancer 1 11 1 Partha M Das, Kavitha Ramachandran, Jane VanWert, Larry Ferdinand, 1 11,2 Gopal Gopisetty, Isildinha M Reisand Rakesh Singal*

1 2 Address: SylvesterComprehensive Cancer Center, University of Miami, Miami, FL – 33136, USA andMiami VA Medical Center, Miami, FL 33136, USA Email: Partha M Das  [e-mail]; Kavitha Ramachandran  [e-mail]; Jane VanWert  [e-mail]; Larry Ferdinand  [e-mail]; Gopal Gopisetty  [e-mail]; Isildinha M Reis  [e-mail]; Rakesh Singal*  [e-mail] * Corresponding author

Published: 18 July 2006Received: 04 January 2006 Accepted: 18 July 2006 Molecular Cancer2006,5:28 doi:10.1186/1476-4598-5-28 This article is available from: http://www.molecular-cancer.com/content/5/1/28 © 2006 Das et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract Background:Transcriptional silencing associated with aberrant promoter methylation has been established as an alternate pathway for the development of cancer by inactivating tumor suppressor genes.TMS1(Target of Methylation induced Silencing), also known asASC(Apoptosis Speck like protein containing a CARD) is a tumor suppressor gene which encodes for a CARD (caspase recruitment domain) containing regulatory protein and has been shown to promote apoptosis directly and by activation of downstream caspases. This study describes the methylation induced silencing ofTMS1/ASCgene in prostate cancer cell lines. We also examined the prevalence ofTMS1/ ASCgene methylation in prostate cancer tissue samples in an effort to correlate race and clinico- pathological features withTMS1/ASCgene methylation. Results:Loss ofTMS1/ASCgene expression associated with complete methylation of the promoter region was observed in LNCaP cells. Gene expression was restored by a demethylating agent, 5-aza-2'deoxycytidine, but not by a histone deacetylase inhibitor, Trichostatin A. Chromatin Immunoprecipitation (ChIP) assay showed enrichment of MBD3 (methyl binding domain protein 3) to a higher degree than commonly associated MBDs and MeCP2. We evaluated the methylation pattern in 66 prostate cancer and 34 benign prostatic hyperplasia tissue samples.TMS1/ASCgene methylation was more prevalent in prostate cancer cases than controls in White patients (OR 7.6, p 0.002) while no difference between the cases and controls was seen in Black patients (OR 1.1, p 0.91). Conclusion:Our study demonstrates that methylation-mediated silencing ofTMS1/ASCis a frequent event in prostate cancer, thus identifying a new potential diagnostic and prognostic marker for the treatment of the disease. Racial differences inTMS1/ASCmethylation patterns implicate the probable role of molecular markers in determining in susceptibility to prostate cancer in different ethnic groups.

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