COBRE; CREIGHTON UNIV; PILOT 1; PROSTATE CANCER: THE ROLE OF G-PROTEIN ALPHA12

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。前列腺癌是美国诊断出的最常见的癌症，大多数诊断出的前列腺癌最终从雄激素依赖型发展为雄激素非依赖型。然而，前列腺癌进展的确切分子机制尚不清楚，这是前列腺癌治疗的主要障碍。本研究项目的长期目标是阐明g蛋白偶联内皮素A受体（ETA R）信号在前列腺癌从雄激素依赖性向雄激素非依赖性进展过程中的确切作用，以及g蛋白信号2调节剂（RGS2）在这一进展过程中调节ETAR信号的分子机制。我们的前期研究选择LNCaP前列腺癌细胞系作为模型。在低传代时，它以雄激素敏感的方式缓慢生长，但在高传代时，它积极生长并失去雄激素依赖性，模仿人类前列腺癌的进展。我们发现，在前列腺癌LNCaP细胞中，ETA R的增加和RGS2表达的缺失与雄激素反应性的丧失有关，这两者都已在人类前列腺肿瘤样本中得到证实。我们的初步研究还表明，这两种改变可能共同促进前列腺癌的进展。我们将通过以下具体目标进一步开展这些初步研究：目标1。确定ETA R信号促进雄激素非依赖性前列腺癌细胞生长的分子机制。我们将研究由ETA R信号引发的ERK活性过度活跃是否与雄激素非依赖性前列腺癌细胞增殖有关。我们还将通过小干扰RNA沉默雄激素受体，以确定雄激素受体在ETA R信号触发的前列腺癌细胞增殖中的重要性。目标2。探讨RGS2在前列腺癌进展中的生物学意义。我们将通过在雄激素依赖型LNCaP细胞中表达诱导型RGS2或在雄激素依赖型LNCaP细胞中使用siRNA沉默RGS2来研究RGS2是否对前列腺癌具有负调控作用。我们还将在培养裸鼠和胸腺裸鼠中研究操纵RGS2对前列腺癌细胞恶性生长的影响。目标3。确定RGS2失调导致前列腺癌进展的分子机制。我们将分析在雄激素受体阳性的LNCaP细胞和其他雄激素受体阴性的前列腺癌细胞系中，操纵RGS2表达是如何负调控ETA R信号和雄激素非依赖性恶性细胞生长的。这些研究的意义在于，它们将提供关于ETA R升高和RGS2缺失共同促进前列腺癌进展的分子机制的重要信息，这些研究得到了强有力的初步数据的支持。因此，开发增加RGS2表达的药物，结合ETA R抑制剂，可能会更有效地成功治疗晚期前列腺癌患者。？

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Prostate cancer is the most common cancer diagnosed in the USA and the majority of prostate cancers diagnosed eventually progress from being androgen-dependent to androgen-independent. However, the precise molecular mechanisms underlying prostate cancer progression are unknown, which presents a major hurdle for the treatment of prostate cancer. The long-term goals of this research program are to elucidate the precise role of G-protein coupled endothelin A receptor (ETA R) signaling in prostate cancer progression from being androgen-dependent to androgen-independent and the molecular mechanisms whereby Regulator of G-protein Signaling 2 (RGS2) modulates the ETAR signaling in this progression. The LNCaP prostate cancer cell line has been chosen as a model in our preliminary studies. It grows slowly in an androgen-sensitive manner at low-passage but grows aggressively and loses androgen-dependence in high-passage, mimicking the progression of human prostate cancers. We found that increased ETA R and loss of RGS2 expression are associated with the loss of androgen-responsiveness in prostate cancer LNCaP cells, which both have been confirmed in human prostate tumor samples. Our preliminary studies also suggested that these two alterations may cooperatively promote prostate cancer progression. We will pursue these preliminary studies further through the following specific aims: Aim 1. To determine molecular mechanisms whereby ETA R signaling promotes androgen-independent prostate cancer cell growth. We will investigate whether the hyperactive ERK activity triggered by ETA R signaling is responsible for androgen-independent prostate cancer cell proliferation. We will also silence androgen receptor by small interfering RNA to determine the importance of androgen receptor in ETA R signaling-triggered proliferation of prostate cancer cells. Aim 2. To study the biological importance of RGS2 in prostate cancer progression. We will investigate whether RGS2 negatively modulates prostate cancer by either expressing inducible RGS2 in androgen-independent LNCaP cells or using siRNA to silence RGS2 in androgen-dependent LNCaP cells. We will also study the effects of manipulating RGS2 on the malignant growth of prostate cancer cells in culture and in athymic nude mice. Aim 3. To determine the molecular mechanisms whereby dysregulation of RGS2 contributes prostate cancer progression. We will analyze how manipulating RGS2 expression negatively regulates the ETA R signaling and androgen-independent malignant cell growth in androgen receptor postitive LNCaP cells and in other androgen receptor negative prostate cancer cell lines. The significance of these studies, which are supported by strong preliminary data, resides in the fact that they will provide important information on the molecular mechanisms whereby increased ETA R and loss of RGS2 cooperatively promote prostate cancer progression. Therefore, development of medicines that increase the RGS2 expression, in combination with ETA R inhibitors, may prove more effective for the successful treatment of advanced prostate cancer patients. ?