Androgen-Independent Prostate Cancer: Mechanisms & Treat

该提案将研究雄激素依赖性前列腺癌（AIPC）进展为雄激素非依赖性前列腺癌的机制。 我们的假设是，AIPC发展的一种机制是雄激素受体（AR）突变，其扩大了其配体结合特异性，并允许非雄激素结合并激活它，从而刺激前列腺癌（PCa）生长。 因此，AIPC的这一亚组依赖于AR，我们将这一途径称为混杂AR。 实例包括LNCaP细胞（突变T877A）和MDA PCa细胞（突变T877A和L701H）中的AR。 虽然通常被称为雄激素依赖性，但这些细胞具有混杂的AR，这些AR是雄激素响应性的，但不依赖于雄激素，因为氟替卡松和其他类固醇可以刺激它们的生长。 该基金有三个具体目标。 目的进一步评价MDA PCa 2a和2b细胞，我们最近将其描述为AIPC的原因，由于对皮质类固醇有反应的混杂AR（ARccr）。 我们将进一步描述与ARccr结合的类固醇，并开发阻断或抑制ARccr的治疗策略。 我们将研究L701H突变和其他AR突变的频率，这些突变导致转移性标本中的混杂AR表型。 最后，我们将利用cDNA微阵列技术研究雄激素和皮质类固醇通过ARccr的基因调控模式。 在Specific Aim II中，我们将研究AR依赖性AIPC的新治疗策略。 我们假设，分子，可以选择性下调AR（SARD）将在治疗AR依赖性AIPC治疗有用。 我们已经确定了一些激素和配体与此活动。 在目的II中，我们将进一步鉴定、表征和阐明SARD的作用机制，并证明其减少AR依赖性AIPC细胞生长刺激的能力。 在具体目标III中，我们将采用两种体内模型来研究目标I和II中开发的治疗策略。 模型1将在裸鼠中采用经典的异种移植物。 模型2是一种新的方法，使用的是可在活小鼠中用电荷耦合器件照相机观察到的经胰蛋白酶转染的PCa细胞异种移植物。 生物发光模型将是对目前异种移植方法的重大改进，提供可重复的前列腺癌进展定量成像，可以检测微观转移。 总之，我们建议在体外和体内实验，以调查的机制，前列腺癌从雄激素依赖性AIPC的过渡，重点在AR和治疗策略，以防止AR依赖性前列腺癌的增长突变。

This proposal will investigate mechanisms of progression from androgen-dependent to androgen-independent prostate cancer (AIPC). Our hypothesis is that one mechanism for AIPC development is mutations in the androgen receptor (AR) that widen its ligand binding specificity, and allow non-androgens to bind to and activate it, thus stimulating prostate cancer (PCa) growth. This sub-group of AIPC is therefore dependent on the AR and we refer to this pathway as the promiscuous AR. Examples include the ARs in LNCaP cells (mutation T877A), and MDA PCa cells (mutations T877A and L701H). Although often referred to as androgen-dependent, these cells have promiscuous ARs that are androgen-responsive but not dependent on androgens since flutamide and other steroids can stimulate their growth. The grant has 3 Specific Aims. Aim I will further evaluate MDA PCa 2a and 2b cells that we have recently described as a cause of AIPC due to a promiscuous AR that responds to corticosteroids (ARccr). We will further characterize the steroids that bind to ARccr and develop treatment strategies to block or suppress the ARccr. We will investigate the frequency of the L701H mutation and other AR mutations that cause the promiscuous AR phenotype in metastatic specimens. Finally, we will investigate the pattern of gene regulation by androgens and corticosteroids via the ARccr using cDNA microarray technology. In Specific Aim II we will study a novel treatment strategy for AR-dependent AIPC. We hypothesize that molecules that can selectively down-regulate AR (SARDs) will be therapeutically useful in treating AR-dependent AIPCs. We have identified a number of hormones and ligands with this activity. In Aim II we will further identify, characterize and elucidate the mechanism of action of SARDs as well as demonstrate their ability to diminish growth stimulation of AR- dependent AIPC cells. In Specific Aim III we will employ two in vivo models to investigate the treatment strategies developed in Aims I and II. Model 1 will employ classic xenografts in nude mice. Model 2 is a new approach using luciferase-transfected PCa cell xenografts that can be observed in live mice with a charge coupled device camera. The bioluminescent model will be a major improvement over current xenograft approaches providing repeatable, quantitative imaging of prostate cancer progression that can detect microscopic metastases. In conclusion, we propose in vitro and in vivo experiments to investigate the mechanism of transition of PCa from androgen-dependent to AIPC, focusing on mutations in the AR and treatment strategies to prevent the growth of AR-dependent PCa.