HORMONAL REGULATION OF ANDROGEN RECEPTOR EXPRESSION

拟议研究的长期目标是了解 内分泌状态对正常人和正常人雄激素受体丰度的影响 并评价其生理学意义。 受体数量的波动。特别是，分子机制 参与雄激素介导的雄激素受体基因表达的调节 将研究表达雄激素的细胞中的蛋白质水平。 受体基因。受体受同源基因调控的能力 配基(自动调节)是几乎所有成员的共同特征 类固醇/甲状腺激素受体家族。在许多靶组织和 雄激素处理含雄激素受体的细胞系引起 受体信使核糖核酸和蛋白质减少。初步结果表明， 人雄激素受体基因在转基因细胞中的表达 也被雄激素下调。由于使用了异源启动子 表达雄激素受体基因对雄激素不敏感， 受体cdna内的序列必须负责自动调节。 转染型雄激素受体基因的表达。这里提出的实验将 检验雄激素介导的雄激素调节假说 受体水平是通过直接相互作用实现的 雄激素受体，其序列在受体基因或信使核糖核酸内。这个 这项建议的具体目标是：一、评估 雄激素对雄激素稳态水平、转录和稳定性的影响 人雄激素受体基因在细胞中的表达。 二、评估雄激素对稳态水平和 雄激素受体蛋白的半衰期。三、鉴定基因内源 雄激素受体基因下调信号的(A)定位 雄激素受体与雄激素内的特定序列结合 受体c DNA(或m RNA)；(B)体外诱变(定点或 缺失)以确定受体结合位点的潜在作用 这些序列处于下调调控中。因为类固醇受体的含量 已证实在预测细胞对类固醇的反应性方面是有用的 激素，了解受体是如何调节的，对 开发合理的内分泌治疗方法。例如，调制 雄激素水平是高血压临床治疗的中心组成部分。 前列腺癌。细胞内分泌状态如何影响雄激素 受体应该有助于肿瘤学家得出更有效的策略 用于治疗雄激素依赖型肿瘤。类固醇受体的研究进展 下调监管将提供对衰减机制的洞察 细胞对激素刺激的反应，这可能参与了 激素耐药肿瘤的临床问题。

The long term objectives of the proposed research are to understand the effects of endocrine status on androgen receptor abundance in normal and diseased target tissues and to evaluate the physiologic significance of fluctuations in receptor number. In particular, the molecular mechanisms involved in androgen-mediated regulation of androgen receptor mRNA and protein levels will be investigated in cells expressing the androgen receptor cDNA. The capacity of receptors to be regulated by cognate ligand (autoregulation) is a feature common to virtually all members of the steroid/thyroid hormone receptor family. In many target tissues and androgen receptor-containing cell lines androgen treatment causes a reduction in receptor mRNA and protein. Preliminary results suggest that the expression of the human androgen receptor cDNA in transfected cells is also down-regulated by androgen. Since the heterologous promoter used to express the androgen receptor cDNA is insensitive to androgens, sequences within the receptor cDNA must be responsible for autoregulation of transfected androgen receptor mRNA. Experiments proposed here will test the hypothesis that androgen-mediated regulation of androgen receptor levels is achieved through the direct interaction of the androgen receptor with sequences within the receptor cDNA or mRNA. The specific aims of this proposal are: I. To evaluate the effects of androgens on steady state levels, transcription and stability of androgen receptor mRNA in cells transfected with the human androgen receptor cDNA. II. TO evaluate the effects of androgens on steady state levels and half-life of androgen receptor protein. III. To identify the intragenic down regulatory signals of the androgen receptor cDNA by (A) mapping androgen receptor binding to specific sequences within the androgen receptor cDNA (or mRNA); (B) in vitro mutagenesis (site directed or deletion) of receptor binding sites to ascertain the potential role of these sequences in down regulation. Since steroid receptor content has proven to be useful in predicting cellular responsiveness to steroid hormones, understanding how receptors are regulated is vital to the development of rational endocrine therapies. For example, modulation of androgen levels is a central component in the clinical management of prostate cancer. How cellular endocrine status affects androgen receptors should aid oncologists in arriving at more effective strategies for treatment of androgen-dependent tumors. Studies on steroid receptor down regulation will provide insight into mechanisms that attenuate cellular response to hormonal stimulation and that may be involved in the clinical problem of steroid-resistant neoplasia.