There are few in vivo models of androgen-dependent prostate cancer (ADPC), and limited availability of the models makes it difficult to evaluate anticancer agents for early stage prostate cancer and to investigate the recurrence of ADPC. We previously reported JDCaP xenograft model, an ADPC model with wild type androgen receptor (AR) and TMPRSS2-ERG gene fusion, derived from skin metastatic lesions of a prostate cancer patient. JDCaP xenografts completely regressed after surgical or medical castration; however, some of them relapsed several months after castration. The relapsed JDCaP subline, designated JDCaP-hr (hormone refractory), was established by serial passage in castrated nude mice. The AR antagonist bicalutamide did not show any effect on tumor growth of JDCaP-hr, while testosterone treatment induced tumor regression of JDCaP-hr, indicating that ligand binding to AR is not necessary, rather cytotoxic, for the growth of JDCaP-hr. Direct sequencing analysis of full length AR revealed that JDCaP-hr retained wild type AR. AR mRNA expression in JDCaP-hr was approximately 7-fold higher than in JDCaP, and interestingly, truncated AR protein with molecular weight of approximately 75 kDa in addition to full length AR (110 kDa) was expressed in JDCaP-hr. Microarray analysis revealed that ubiquitin-dependent protein catabolism pathway was markedly upregulated in JDCaP-hr compared with JDCaP. JDCaP-hr cells proliferated in vitro in steroid-free medium under co-culture condition with mouse stromal cells, and secreted prostate-specific antigen into the conditioned medium. Taken together, JDCaP/JDCaP-hr is a valuable model which simulates the recurrence of ADPC to castration-resistant prostate cancer (CRPC) with common clinical features such as AR overexpression. This model provides not only useful in vivo and in vitro systems to evaluate anticancer agents for ADPC and CRPC but also intriguing implications for the recurrence of ADPC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3247.