1424 METHYLATION AND DECREASED EXPRESSION OF 5-ALPHA REDUCTASE 2 IN HUMAN PROSATE SAMPLES: IMPLICATIONS FOR RESISTANCE TO THERAPY FOR BPH

Abstract

You have accessJournal of UrologyBenign Prostatic Hyperplasia: Basic Research1 Apr 20101424 METHYLATION AND DECREASED EXPRESSION OF 5-ALPHA REDUCTASE 2 IN HUMAN PROSATE SAMPLES: IMPLICATIONS FOR RESISTANCE TO THERAPY FOR BPH Yinong Niu, Libing Hu, Rongbin Ge, Zongwei Wang, Chin-Lee Wu, and Aria Olumi Yinong NiuYinong Niu More articles by this author , Libing HuLibing Hu More articles by this author , Rongbin GeRongbin Ge More articles by this author , Zongwei WangZongwei Wang More articles by this author , Chin-Lee WuChin-Lee Wu More articles by this author , and Aria OlumiAria Olumi More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2010.02.1116AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES 5-alpha reductase type 2 (5-AR2), an enzyme that is critical for prostatic development and growth, is utilized as an inhibitory target by Finasteride for patients with BPH. However, many patients are resistant to the therapeutic effects Finasteride. Here, we demonstrate that some patients do not express the 5-AR2 protein, and as a result maybe resistant to the therapeutic effects of Finasteride. We show that methylation of 5-AR2 in human samples is associated with lack of 5-AR2 protein expression. METHODS The transition zone of 21 one fresh human prostate samples after radical prostatectomy were used for evaluation. Immunoreactivity of 5-AR2 was assessed in benign hyperplastic prostate (BPH) tissue was assessed. RNA expression of 5-AR2 was determined by RT-PCR. Methylation of 5-AR2 gene in prostate epithelial cell lines and primary prostate tissues were analyzed by using methyl-specific RT-PCR. Expression of cell viability was assessed by flow cytometry and MTS assays. Co-culture between normal human prostate fibroblasts and BPH-1 and LNCaP cells were completed. Western and Northern blot analyses were performed to check for expression of Akt, ERK 1/2, PSA, 5-AR-2, 5-AR-1, Bcl-2, Ki-67. RESULTS Immunohistochemical assessment of 21 BPH samples revealed that 29% (6/21) did not express the 5-AR2 protein. 5-AR2 contains a rich CpG island in its promoter region, and immortalized prostate epithelial cells which do not express 5-AR2 protein, were heavily methylated in the promoter region of 5-AR2 gene. In human prostate samples that were available for PCR analysis, 44% (8/18) demonstrated low 5-AR2 RNA expression, and 38% (7/18) of the prostate samples were methylated in the 5-AR2's promoter region. Chi-square modeling demonstrated significant correlation between methylation of 5-AR2 promoter region and expression of 5-AR2 protein (p=0.011). While mono-cultures of immortalized prostate cell lines (BPH-1 and LNCaP) were resistant to the therapeutic effects of Finasteride, co-cultures with human prostate fibroblasts restored the pro-apoptotic and anti-proliferative functions of Finasteride. CONCLUSIONS Expression of 5-AR2 is variable and absent in some adult prostatic tissues. There is a strong correlation between methylation of 5-AR2 promoter region and low expression levels of 5-AR2 protein. Low or absent levels of 5-AR2 may explain why some patients with BPH are resistant to the therapeutic effects 5-AR2 inhibitors. Boston, MA© 2010 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 183Issue 4SApril 2010Page: e549 Advertisement Copyright & Permissions© 2010 by American Urological Association Education and Research, Inc.MetricsAuthor Information Yinong Niu More articles by this author Libing Hu More articles by this author Rongbin Ge More articles by this author Zongwei Wang More articles by this author Chin-Lee Wu More articles by this author Aria Olumi More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...