Androgen-Independent Prostate Cancer: Mechanisms & Treat

雄激素非依赖性前列腺癌：机制

基本信息

批准号：
6723625
负责人：
David Feldman
金额：
$ 34.99万
依托单位：
STANFORD UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2002
资助国家：
美国
起止时间：
2002-04-01 至 2006-03-31
项目状态：
已结题

项目摘要

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.

该建议将研究从雄激素依赖性到雄激素独立前列腺癌（AIPC）进展的机制。我们的假设是，AIPC发育的一种机制是雄激素受体（AR）中的突变，它扩大了其配体结合特异性，并允许非赋料结合并激活其，从而刺激前列腺癌（PCA）生长。因此，AIPC的这种子组取决于AR，我们将此途径称为混杂的AR。示例包括LNCAP细胞中的ARS（突变T877A）和MDA PCA细胞（突变T877A和L701H）。尽管通常称为雄激素依赖性，但这些细胞具有混杂的ARS，它们是雄激素反应性的，但不依赖于雄激素，因为氟他胺和其他类固醇可以刺激其生长。该赠款有3个具体目标。目的，我将进一步评估我们最近将其描述为AIPC的MDA PCA 2A和2B细胞，这是由于对皮质类固醇（ARCCR）响应的滥交AR。我们将进一步表征与ARCCR结合并制定治疗策略以阻止或抑制ARCCR的类固醇。我们将研究L701H突变和其他AR突变的频率，这些突变引起转移性标本中的混杂AR表型。最后，我们将使用cDNA微阵列技术通过ARCCR研究雄激素和皮质类固醇的基因调节模式。在特定目标II中，我们将研究针对AR依赖性AIPC的新型治疗策略。我们假设可以选择性下调AR（SARD）的分子在治疗依赖AR依赖性AIPC上是有用的。我们已经确定了许多活性的激素和配体。在AIM II中，我们将进一步识别，表征和阐明SARD的作用机理，并证明其减少AR依赖性AIPC细胞生长刺激的能力。在特定的目标III中，我们将采用两个体内模型来研究目标I和II中制定的治疗策略。 Model 1将在裸鼠中采用经典的异种移植物。模型2是一种使用荧光素酶转染的PCA细胞异种移植物的新方法，可以在活小鼠中使用电荷耦合器件摄像头观察到。生物发光模型将比当前的异种移植方法进行重大改进，从而提供可重复的，可重复的前列腺癌进展的定量成像，可以检测显微镜转移。总之，我们提出了体外和体内实验，以研究PCA从雄激素依赖到AIPC的过渡机制，重点是AR中的突变和治疗策略，以防止AR依赖性PCA的生长。