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，导致每年约有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，或者最好是预防CR CaP的出现。在本提案中，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CR CaP细胞中的表达是由异常激活的AR控制的，miR-125b通过抑制p53网络的功能促进CaP细胞的CR生长，miR-125b具有作为CaP患者管理的生物标志物和治疗靶点的潜力。我们将追求三个特定的目标来验证这一假设。目的1是表征ar介导的miR-125b在前列腺癌中的调节作用。我们将证实AR信号调节miR-125b，并确定过表达的AR是否在CR细胞中异常激活并随后上调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是表征miR-125b在前列腺癌中的功能。我们将证实miR-125b通过抑制p53、Puma、Bak1和p14ARF的表达来促进肿瘤发生和CR生长，确定miR-125b在抗凋亡和促进细胞增殖中的作用，并评估miR-125b对AR水平和活性的影响。这些实验所获得的数据将为miR-125b介导的前列腺肿瘤发生和CR生长提供机制解释。目的3是表征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是否会改变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，并有望作为CaP治疗的靶点。综上所述，该提案包含技术和概念上的创新，并具有重大的转化潜力。完成这些拟议的研究将获得有价值的数据，并为CaP如何变得抗去势提供新的见解。

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.