ANDROGEN RECEPTOR FUNCTION IN RECURRENT PROSTATE CANCER

描述：(申请人的描述)人类的前列腺是雄激素依赖性的，前列腺癌(CAP)，维持这种对雄激素的依赖。在雄激素停用后，CAP经历了细胞凋亡和退化，但在缺乏睾丸雄激素的情况下最终复发。在雄性裸鼠体内繁殖的人帽异种移植(CWR22)保留了这些生物学特性，包括去势后的退化和在没有睾丸雄激素的情况下几个月后复发。停止雄激素刺激后，CWR22的AR水平下降。然而，与去势小鼠退化的CWR22相比，复发的CWR22肿瘤表达高水平的AR。在复发的CWR22中，在没有雄激素的情况下，核免疫染色的增强与AR激活是一致的。此外，雄激素调节的mRNAs在去势后CWR22肿瘤中减少，在复发的XWR22肿瘤中上调。本研究的目的是建立AR和AR靶基因网络在雄激素非依赖性CAP生长中的作用。本项目的具体目的是：(1)阐明CWR 22肿瘤去势和复发后AR基因和蛋白稳定表达水平的调控机制。研究复发CWR22肿瘤中AR(蛋白质稳定性和磷酸化)的激活特性。(2)筛选CWR22中雄激素调控基因，重点研究AR刺激细胞生长的潜在调节因子。比较这些雄激素调节基因在CWR22中的表达水平，重点放在AR刺激的细胞生长的潜在介质上。比较这些雄激素调节基因在去势小鼠中的表达水平。(3)用显性负性AR抑制AR反式激活，用AR导向的核酶抑制AR的表达，以确定复发CWR22肿瘤中AR的雄激素非依赖性功能。(4)阐明雄激素调控基因在CWR22复发中的表达机制：(A)AR依赖机制；(B)非AR依赖机制。

Description: (Applicant's Description) The human prostate is androgen dependent and prostate cancer (CaP), maintains this dependence on androgens. CaP undergoes apoptosis and regression following androgen withdrawal but eventually recurs in the absence of testicular androgens. The human CaP xenograft (CWR22) propagated in male nude mice, retains these biological characteristics including regression following castration and recurrence of growth after several months in the absence of testicular androgen. Following the withdrawal of androgen stimulation, AR levels decrease in CWR22. However, recurrent CWR22 tumors express high levels of AR relative to the regressing CWR22 from castrated mice. In recurrent CWR22 the increased intensity of nuclear immunostaining is consistent with AR activation in the absence of androgen. Moreover, androgen-regulated mRNAs that decrease in CWR22 tumors following castration are up-regulated in the recurrent XWR22. The goal of this research is to establish the role of AR and the AR target gene network in the androgen-independent growth of CaP. Specific Aims of this project are to: (1) Delineate the mechanisms controlling steady state expression levels of AR mRNA and protein in CWR 22 tumors after castration and recurrent growth. Characterize the activation properties of AR (protein stability and phosphorylation) in recurrent CWR22 tumors. (2) Identify androgen-regulated genes in CWR22 with emphasis on potential mediators of AR-stimulated cell growth. Compare the levels of expression of these androgen-regulated genes in CWR22 with emphasis on potential mediators of AR-stimulated cell growth. Compare the levels of expression of these androgen- regulated genes in castrate mice. (3) Determine the androgen-independent function of AR in the recurrent CWR22 tumors using a dominant- negative AR to inhibit AR to inhibit AR transactivation and an AR- directed ribozyme to prevent AR expression. (4) Elucidate the mechanism controlling expression of androgen-regulated genes in the recurrent CWR22 (a) AR-dependent mechanism; or (b) non-AR dependent mechanism.