COBRE; CREIGHTON UNIV; P10; PROSTATE CANCER: THE ROLE OF G-PROTEIN ALPHA12

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 前列腺癌是美国确诊的最常见的癌症，大多数确诊的前列腺癌最终从雄激素依赖进展到雄激素非依赖性。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。本研究的长期目标是阐明G蛋白偶联的内皮素A受体(ETAR)信号在前列腺癌从雄激素依赖到雄激素非依赖性进展中的确切作用，以及G蛋白信号调节因子2(RGS2)在这一过程中调节ETAR信号的分子机制。 在我们的初步研究中，我们选择了LNCaP前列腺癌细胞系作为模型。它在低传代时生长缓慢，对雄激素敏感，但在高传代时生长迅速，失去对雄激素的依赖，这与人类前列腺癌的发展过程相似。我们发现，前列腺癌LNCaP细胞中ETA R的增加和RGS2表达的丢失与雄激素反应性的丧失有关，这两点在人类前列腺癌样本中都得到了证实。我们的初步研究还表明，这两种改变可能协同促进前列腺癌的进展。我们将通过以下具体目标进一步进行这些初步研究：目的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ETA R信号引发的ERK高活性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。目的2.研究RGS2在前列腺癌进展中的生物学意义。我们将研究RGS2是否通过在雄激素非依赖的LNCaP细胞中表达可诱导的RGS2或在雄激素依赖的LNCaP细胞中使用siRNA沉默RGS2来负向调节前列腺癌。我们还将研究操纵RGS2对前列腺癌细胞在培养和裸鼠体内恶性生长的影响。目的3.确定RGS2基因异常促进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表达如何负面调节ETA R信号和雄激素非依赖性恶性细胞的生长。 这些有强有力的初步数据支持的研究的意义在于，它们将提供关于ETA R增加和RGS2丢失协同促进前列腺癌进展的分子机制的重要信息。因此，开发增加RGS2表达的药物，与ETA R抑制剂联合使用，可能会证明对晚期前列腺癌患者的成功治疗更有效。？

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. ?