Regulation of AR function by NOS

描述(申请人提供)：一氧化氮合酶对AR功能的调节。雄激素受体(AR)是一种配体控制的转录因子，负责调节雄激素在靶问题上的所有生物学行为，包括男性性发育和维持男性性特征。AR基因的突变可以导致雄激素不敏感综合征，影响正常的男性形态发生，而不受调控的AR信号与肯尼迪病的发生有关，肯尼迪病是一种影响下运动神经元的进行性退行性疾病。值得注意的是，临床和实验室证据表明，AR在前列腺癌中发挥着关键作用，前列腺癌是男性癌症死亡的第二大原因。最近的工作已经确定了AR的激活突变，携带突变AR的转基因动物会发生前列腺上皮内瘤变，进而发展为浸润性前列腺癌。参与调节AR功能障碍(因此，对人类疾病的贡献)的机制仍然不完整。我们的初步数据表明，前列腺癌细胞内源性表达一氧化氮合酶，在LNCaP细胞中过表达一氧化氮合酶可抑制雄激素诱导的AR激活，并抑制体外细胞增殖和动物移植瘤生长。在体外，药物抑制NOS活性可增强雄激素调节的AR的激活，而siRNA抑制NOS的表达可增加AR与前列腺特异性抗原启动子的关联。AR与一氧化氮合酶形成复合体，并被S亚硝化(即NO基团与半胱氨酸残基的共价结合)翻译后修饰。为了验证一氧化氮合酶及其产物一氧化氮调节AR功能以控制前列腺癌细胞增殖的假说，我们提出了两个具体的目的：[i]确定一氧化氮合酶的表达、药物一氧化氮合酶抑制剂和一氧化氮供体对AR功能和前列腺细胞增殖的影响，[ii]阐明一氧化氮合酶和一氧化氮调节AR功能和前列腺细胞增殖的机制，重点是AR S亚硝化作用。一氧化氮合酶的靶向激活，或在没有供体的情况下进行治疗，有望成为成功治疗前列腺癌的一种特异的分子治疗工具。前列腺癌是美国男性癌症相关死亡的主要原因，雄激素受体参与了疾病的发生和发展。我们发现雄激素受体被S亚硝化修饰，从而抑制其功能。一氧化氮合酶的靶向激活或NO供体的治疗可能成为成功治疗前列腺癌患者的一种特异的分子治疗工具。

DESCRIPTION (provided by applicant): Regulation of AR Function by NOS. The androgen receptor (AR) is a ligand-controlled transcription factor that is responsible for mediating all biological actions of androgens in target issues, including male sexual development and maintenance of male sex characteristics. Mutations in the AR gene can cause the androgen-insensitivity syndrome that affects normal male morphogenesis, and unregulated AR signaling has been linked to the development of Kennedy's disease, a progressive degenerative condition affecting lower motor neurons. Significantly, clinical- and laboratory-based evidence demonstrates that AR plays a critical role in prostate cancer, the second leading cause of cancer death in men. Recent work has identified activating mutations in AR, and transgenic animals harboring the mutated AR develop prostatic intraepithelial neoplasia that progress to invasive prostate cancer. Mechanisms involved in the regulation of AR dysfunction (and, therefore, contribution to human disease) remain incomplete. Our preliminary data show that NOS is endogenously expressed in prostate cancer cells, and that overexpression of NOS in LNCaP cells attenuates the androgen-induced AR activation, and inhibits cell proliferation in vitro and xenograft tumor growth in animals. Pharmacologic inhibition of NOS activity enhances androgen-regulated AR activation in vitro, and knockdown of NOS expression with siRNA increases the AR association with prostate-specific antigen promoter. The AR forms a complex with NOS and is post-translationally modified by S- nitrosylation (i.e. the covalent attachment of a NO group to cysteine residue). We propose two specific aims to test the hypothesis that NOS and its product NO regulate AR function to control prostate cancer cell proliferation: [i] to establish effects of NOS expression and pharmacologic NOS inhibitors and NO donors on AR function, and prostate cell proliferation, and [ii] to elucidate the mechanisms by which NOS and NO regulate AR function and prostate cell proliferation with emphasis on AR S-nitrosylation. The targeted activation of NOS, or treatment with NO donors is hoped to serve as a specific molecular therapy tool to successfully treat prostate cancer. Prostate cancer is the leading cause of cancer-related death of American men, and androgen receptor is involved in the initiation and progression of the disease. We found that androgen receptor is modified by S-nitrosylation, which inhibits its function. The targeted activation of NOS, or treatment with NO donors may serve as a specific molecular therapy tool to successfully treat patients with prostate cancer.