Identification and characterization of the functional role of miRNA in prostate c

描述(由申请人提供)：我们对前列腺癌(CAP)的去势抵抗(CR)生长相关的分子事件缺乏了解，导致每年约27,360名美国男性死于这种疾病。PI的长期目标是开发有效的治疗方法来治疗或最好是预防CR帽的出现。在这项提案中，我们将探讨我们最近发现的miR-125b在前列腺癌中的异常表达。我们的假设是，miR-125b在CAP细胞中的表达受异常激活的AR控制，miR-125b通过抑制P53网络功能促进CAP细胞的CR生长，miR-125b有可能作为CAP患者治疗的生物标志物和治疗靶点。为了检验这一假设，我们将追求三个具体目标。目的1是研究AR介导的miR-125b在前列腺癌中的调节作用。我们将确认AR信号调节miR-125b，并确定在CR细胞中过度表达的AR是否异常激活，随后上调miR-125b。这些实验将解决为什么CR CAP细胞和晚期CAP肿瘤表达高水平miR-125b的问题。目的2研究miR-125b在前列腺癌中的作用。我们将证实miR-125b通过抑制p53、Puma、Bak1和p14ARF的表达来促进肿瘤的发生和CR的生长，确定miR-125b在抗细胞凋亡和促进细胞增殖中的作用，并评价miR-125b对AR水平和活性的影响。从这些拟议的实验中获得的数据将提供miR-125b介导的前列腺癌发生和CR生长的机制解释。目的3是鉴定miR-125b作为前列腺癌的潜在生物标志物或治疗靶点。我们将检测临床CAP样本和CAP患者血清中异常表达miR-125b的频率，并确定miR-125b是否改变CAP细胞对治疗的反应。这些研究将促进该miRNA作为CAP诊断和预后的生物标志物的应用，并有望成为CAP治疗的靶点。总而言之，这项提议既有技术上的创新，也有概念上的创新，并具有巨大的翻译潜力。这些拟议研究的完成将获得有价值的数据，并为CAP如何抵抗阉割提供新的见解。 公共卫生相关性：耐去势前列腺癌是对美国男性生命的主要威胁，2009年约有27,360名美国男性死于这种疾病。这种疾病没有治愈的主要原因是对前列腺癌中发生的分子变化缺乏了解。在这项拨款申请中，我们将探索我们最近的发现，前列腺癌高表达microRNA miR-125b，这是一种内源性小RNA，在人类前列腺癌和其他类型的人类癌症中负调控一些肿瘤抑制基因。我们建议调查为什么前列腺癌细胞异常表达miR-125b，以及这种microRNA如何在去势环境中促进前列腺癌的生长。完成这些研究不仅将为与抗去势生长相关的分子变化提供新的见解，还将促进这种microRNA作为诊断和治疗这种疾病的靶标的应用。

DESCRIPTION (provided by applicant): Our lack of understanding of the molecular events related to castrate-resistant (CR) growth of prostate cancer (CaP), results in the death of approximately 27,360 American men each year from this disease. The PI's long-term goal is to develop effective therapies for treating, or preferably preventing, the emergence of CR CaP. In this proposal, we will explore our recent discovery of aberrant expression of miR-125b in prostate cancer. Our hypothesis is that the expression of miR-125b in CR CaP cells is controlled by aberrantly-activated AR, that miR-125b facilitates CR growth of CaP cells by repressing the function of the p53 network, and that miR-125b has potential as a biomarker and a therapeutic target for the management of patients with CaP. Three specific Aims will be pursued to test this hypothesis. Aim 1 is to characterize the AR-mediated regulation of miR-125b in prostate cancer. We will confirm that AR signaling regulates miR-125b and determine whether overexpressed AR is aberrantly-activated in CR cells and subsequently upregulates miR-125b. These experiments will address the issue of why CR CaP cells and advanced CaP tumors express high levels of miR-125b. Aim 2 is to characterize the functions of miR-125b in prostate cancer. We will confirm that miR-125b stimulates tumorigenesis and CR growth by repressing the expression of p53, Puma, Bak1 and p14ARF, determine the role of miR-125b in anti-apoptosis and promoting cell proliferation, and evaluate the effects of miR-125b on the level and activity of AR. Data obtained from these proposed experiments will provide a mechanistic explanation of miR-125b-mediated prostatic tumorigenesis and CR growth. Aim 3 is to characterize miR-125b as a potential biomarker or therapeutic target for prostate cancer. We will detect the frequency of aberrantly-expressed miR-125b in clinical CaP samples and in sera from CaP patients and determine if miR-125b alters the response of CaP cells to therapy. These studies will facilitate the application of this miRNA as a biomarker for CaP diagnosis and prognosis and hopefully, as a target for CaP treatment. In summary, this proposal contains both technical and conceptual innovation, and has significant translational potential. Completion of these proposed studies should obtain valuable data and provide new insights into how CaP becomes castration-resistant. PUBLIC HEALTH RELEVANCE: Castration-resistant prostate cancer represents a major threat to the life of American men, resulting in the death of approximately 27,360 American men in 2009 from this disease. The main reason this disease has not been cured is lack of knowledge about the molecular alterations that occur in prostate cancer. In this grant application, we will explore our recent findings that prostate cancers highly express the microRNA miR-125b that is an endogenous small RNA and negatively regulates some tumor suppressor genes in human prostate cancer and other types of human cancer. We propose to investigate why prostate cancer cells aberrantly express miR-125b and how this microRNA promotes the growth of prostatic tumors in a castration environment. Completing these studies will not only provide new insights into the molecular alterations related to castration-resistant growth, it will also facilitate the application of this microRNA as a biomarker for diagnosis and as a target for treatment of this disease.