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// Hiroki Tamaki 1, 2 , Nanae Harashima 1 , Miho Hiraki 3 , Naoko Arichi 3 , Nobuhiro Nishimura 2 , Hiroaki Shiina 3 , Kohji Naora 2 , Mamoru Harada 1 1 Department of Immunology, Shimane University Faculty of Medicine, Shimane, Japan. 2 Department of Pharmacy, Shimane University Hospital, Shimane, Japan. 3 Department of Urology, Shimane University Faculty of Medicine, Shimane, Japan. Correspondence to: Mamoru Harada, e-mail: haramamo@med.shimane-u.ac.jp Keywords: prostate cancer, docetaxel, apoptosis, Bcl-2, Bcl-xL Received: July 26, 2014 Accepted: September 30, 2014 Published: October 15, 2014 ABSTRACT Docetaxel (DTX) is a useful chemotherapeutic drug for the treatment of hormone-refractory prostate cancer. However, emergence of DTX resistance has been a therapeutic hurdle. In this study, we investigated the effect of combining DTX with Bcl-2 family inhibitors using human prostate cancer cell lines (PC3, LNCaP, and DU145 cells). PC3 cells were less sensitive to DTX than were the other two cell lines. In contrast to ABT-199, which inhibits Bcl-2 and Bcl-w, both ABT-263 and ABT-737, which inhibit Bcl-2, Bcl-xL, and Bcl-w, significantly augmented the antitumor effect of DTX on PC3 cells. ABT-263 also enhanced the antitumor effect of DTX on a DTX-resistant PC3 variant cell line. The antitumor effect of ABT-263 was due mainly to its inhibitory effect on Bcl-xL. In a xenograft mouse model, DTX and ABT-737 combination therapy significantly inhibited PC3 tumor growth. Interestingly, although ABT-263 activated caspase-9 in PC3 cells, inhibition of caspase-9 unexpectedly promoted ABT-263-induced apoptosis in a caspase-8-dependent manner. This augmented apoptosis was also observed in LNCaP cells. These findings indicate that Bcl-xL inhibition can sensitize DTX-resistant prostate cancer cells to DTX, and they reveal a unique apoptotic pathway in which antagonism of Bcl-2 family members in caspase-9-inhibited prostate cancer cells triggers caspase-8-dependent apoptosis.

// Yozo Mitsui 1 , Hiroaki Yasumoto 1 , Taichi Nagami 1 , Miho Hiraki 1 , Naoko Arichi 1 , Noriyoshi Ishikawa 2 , Asuka Araki 2 , Riruke Maruyama 2 , Yuichiro Tanaka 3 , Rajvir Dahiya 3 , Hiroaki Shiina 1 1 Departments of Urology, Shimane University Faculty of Medicine, 89-1 Enya-cho, 693-8501 Izumo, Japan 2 Pathology (Organ Pathology Unit), Shimane University Faculty of Medicine, 89-1 Enya-cho, 693-8501 Izumo, Japan 3 Department of Urology, San Francisco Veterans Affairs Medical Center and University of California at San Francisco, San Francisco, California, USA Correspondence: Yozo Mitsui, email: // Keywords : adrenocortical tumor, Wif-1, epigenetics, Wnt signaling, cyclin D1 Received : March 24, 2014 Accepted : April 07, 2014 Published : April 08, 2014 Abstract Wnt/β-catenin signaling is considered to be an essential regulator of adrenocortical oncogenesis. Wnt inhibitory factor-1 (Wif-1), an extracellular regulator of Wnt signaling, is frequently down-regulated by hypermethylation of the promoter CpG. We investigated epigenetic regulation of Wif-1 and its association with adrenocortical (AC) tumor pathogenesis in light of Wnt activation. The AC tumors showed a high prevalence of Wif-1 promoter methylation and low prevalence of Wif-1 mRNA transcription as compared to the normal adrenal (NA) samples. Furthermore, a significant correlation was found between Wif-1 promoter methylation and mRNA transcription in the tumors. Either intracellular β-catenin accumulation or β-catenin mRNA transcription was significantly elevated in the AC tumors, which also showed an inverse correlation with Wif-1 mRNA transcription. Cyclin D1, a target gene of Wnt signaling, was also up-regulated in the AC tumors as compared with the NA samples. In addition, down-regulation of Wif-1was correlated with increased cyclin D1 at both mRNA and protein levels. However, despite the proposed activation of Wnt signaling in AC tumors, only 2 of 20 with intracellular β-catenin accumulation showed β-catenin mutations. Thus, genetic alterations of β-catenin and epigenetics-related Wif-1 promoter hypermethylation may be important mechanisms underlying AC tumor formation through aberrant canonical Wnt/β-catenin signaling activation.

// 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.