Interference with Androgen Receptor and Its Ligands

项目1带来了两个改变范式的发现。首先，雄激素受体（AR）通路似乎对去势复发性前列腺癌（CaP）的生长至关重要，尽管睾丸循环雄激素水平已被阉割。其次，去势复发性CaP产生高水平的组织睾酮(T)和双氢睾酮（DHT），这是首选的AR配体。卵巢内产生的睾丸雄激素是新疗法的靶点。进一步的进展可能是在CaP细胞死亡最多，存活细胞承受最大压力的情况下，将新的治疗方法与雄激素剥夺疗法（ADT）同时应用于CaP。所提出的研究的中心假设是，通过协同攻击卵巢内雄激素代谢和AR，同时消除循环睾丸雄激素（药物或手术阉割），CaP可以治愈或延长缓解期。为了验证这一假设，并允许在晚期CaP中制定适当的临床试验，将在阉割后立即使用临床前模型评估对ADT的反应。一般来说，单元格或

Project 1 has contributed to two paradigm changing discoveries. First, the androgen receptor (AR) pathway appears critical to the growth of castration-recurrent prostate cancer (CaP) in spite of castrate levels of circulating testicular androgens. Second, castration-recurrent CaP produces high tissue levels of testosterone (T) and dihydrotestosterone (DHT), the preferred AR ligand. Intracrine-produced testicular androgens present a target for novel therapies. Further advances may result from applying novel treatments to CaP coincidental with androgen deprivation therapy (ADT) when CaP cell death is at a maximum and surviving cells are under greatest stress. The central hypothesis of the proposed studies is that CaP can be cured or remission extended by a coordinated attack upon intracrine androgen metabolism and AR coincidental with elimination of circulating testicular androgens (medical or surgical castration). In order to test this hypothesis and allow the formulation of an appropriate clinical trial in advanced CaP, the response to ADT will be assessed using preclinical models in the immediate post-castration period. In general, cell or tissue sampling will be conducted just prior to castration and 12h and 1, 2, 4, 8, 16 and 30d after "castration." The effect of castration upon the androgen axis will be assessed on 4 levels in vitro and 6 levels in vivo. The 4 levels of assessment in vitro and in vivo will include 1) changes in androgen metabolism enzymes at the mRNA level using qRT-PCR and protein level using immunohistochemistry (IHC); 2) androgen levels using LC-MS; 3) androgen-regulated gene expression using IHC for PSA, Nkx3.1 and hK2; and 4) cell growth. Measures in vivo will include 5) time to progression and 6) survival. Androgen metabolism after ADT will be studied using androgen-sensitive CWR22 cell suspensions, the androgen-dependent CWR22 xenograft and a fresh surgical tissue xenograft model. Changes in androgen metabolism critical for survival after ADT will be targeted using shRNA or drug in vitro and lentiviral shRNA and/or drug in vivo (Aim 1). Testicular androgens formed by intracrine metabolism of adrenal androgens will be removed using 53-reductase or Sult2A1 delivered using lentiviral infection (Aim 2). Finally, AR will be removed using lentiviral AR shRNA constructs or AR degrading small molecules (Aim 3).