Inactivation of bone morphogenetic protein 2 may predict clinical outcome and poor overall survival for renal cell carcinoma through epigenetic pathways

// Yozo Mitsui 1,2 , Hiroshi Hirata 2 , Naoko Arichi 1 , Miho Hiraki 1 , Hiroaki Yasumoto 1 , Inik Chang 3 , Shinichiro Fukuhara 4 , Soichiro Yamamura 2 , Varahram Shahryari 2 , Guoren Deng 2 , Sharanjot Saini 2 , Shahana Majid 2 , Rajvir Dahiya 2 , Yuichiro Tanaka 2 and Hiroaki Shiina 1 1 Department of Urology, Shimane University Faculty of Medicine, Enya-cho, Izumo, Japan 2 Department of Urology, San Francisco Veterans Affairs Medical Center and University of California San Francisco, San Francisco, California, USA 3 Department of Oral Biology, Yonsei University College of Densitry, Seoul, South Korea 4 Department of Urology, Osaka University Graduate School of Medicine, Suita, Japan Correspondence to: Yozo Mitsui, email: // Keywords : bone morphogenetic protein 2, renal cell carcinoma, DNA methylation, molecular marker Received : January 15, 2015 Accepted : February 10, 2015 Published : March 07, 2015 Abstract We investigated whether impaired regulation of bone morphogenetic protein-2 (BMP-2) via epigenetic pathways is associated with renal cell carcinoma (RCC) pathogenesis. Expression and CpG methylation of the BMP-2 gene were analyzed using RCC cell lines, and 96 matched RCC and normal renal tissues. We also performed functional analysis using BMP-2 restored RCC cells. A significant association of BMP-2 mRNA expression was also found with advanced tumor stage and lymph node involvement, while lower BMP-2 mRNA expression was significantly associated with poor overall survival after radical nephrectomy. In RCC cells, BMP-2 restoration significantly inhibited cell proliferation, migration, invasion, and colony formation. In addition, BMP-2 overexpression induced p21 WAF1/CIP1 and p27 KIP1 expression, and cellular apoptosis in RCC cells. BMP-2 mRNA expression was significantly enhanced in RCC cells by 5-aza-2’-deoxycitidine treatment. The prevalence of BMP-2 promoter methylation was significantly greater and BMP-2 mRNA expression was significantly lower in RCC samples as compared to normal kidney samples. Furthermore, a significant correlation was found between BMP-2 promoter methylation and mRNA transcription in tumors. Aberrant BMP-2 methylation and the resultant loss of BMP-2 expression may be a useful molecular marker for designing improved diagnostic and therapeutic strategies for RCC.