Role of RNase L in the Biology of Prostate Cancer

描述（由申请人提供）：最近，干扰素（IFN）抗病毒途径和前列腺癌遗传学令人惊讶地聚集在核糖核酸酶L （RNase L）上，这是一种独特的调节酶，需要5'-三磷酸基，2',5'-连接的低聚腺苷酸（2- 5a）才能发挥活性。RNASEL在遗传性前列腺癌1 （HPC1）影响家族中与疾病分离的种系突变和肿瘤组织中杂合性缺失（LOH）的存在，表明RNase L在前列腺癌发病机制中的新作用。我们的初步数据提示RNase L介导前列腺癌细胞凋亡，并提示RNase L在小鼠中具有肿瘤抑制作用。我们建议利用细胞培养和动物模型以及从前列腺癌患者中分离的RNA来研究RNase L在前列腺癌中的基本作用。我们的假设是RNase L通过影响细胞生长和凋亡之间的平衡来抑制前列腺癌的发展。我们的具体目标是：(1)研究前列腺癌细胞中IFN和雄激素对2-5A/RNase L系统的调控，并鉴定前列腺肿瘤RNA中2-5A合成酶的病毒和/或细胞RNA激活因子；(2)在病毒感染、dsRNA治疗或雄激素剥夺前，通过短干扰rna （sirna）下调前列腺癌细胞中RNase L和RNase L抑制剂（RLI）水平，探索凋亡信号通路；(3)研究RNase L对野生型或RNASEL缺失小鼠前列腺生物学的影响，并结合其他与前列腺癌发病机制相关的基因（p53和NKX3.1）或dsRNA介导的细胞凋亡（蛋白激酶PKR）的缺失。

DESCRIPTION (provided by applicant): Recently, the interferon (IFN) antiviral pathways and prostate cancer genetics and have surprisingly converged on ribonuclease L (RNase L), a uniquely regulated enzyme that requires 5'-triphosphoryl, 2',5'- linked oligoadenylates (2-5A) for its activity. The presence of both germline mutations in RNASEL segregating with disease within hereditary prostate cancer 1 (HPC1)-affected families and loss of heterozygosity (LOH) in tumor tissues point to a novel role for RNase L in the pathogenesis of prostate cancer. Our preliminary data implicate RNase L in mediating prostate cancer cell apoptosis and suggest that RNase L functions as a tumor suppressor in mice. We propose to study the fundamental role of RNase L in prostate cancer using cell culture and animal models and in RNA isolated from prostate cancer patients. Our hypothesis is that RNase L suppresses development of prostate cancer by affecting the balance between cell growth and apoptosis. Our specific aims are to: (1) study regulation of the 2-5A/RNase L system by IFN and androgen in prostate cancer cells and to identify viral and/or cellular RNA activators of 2-5A synthetase in prostate tumor RNA; (2) downregulate RNase L and RNase L inhibitor (RLI) levels with short interfering RNAs (siRNAs) in prostate cancer cells prior to viral infection, dsRNA treatment or androgen deprivation and probe the apoptotic signaling pathway; and (3) study the effect of RNase L on prostate biology in mice that are wild type or deficient in RNASEL in combination with loss of other genes implicated in prostate cancer pathogenesis (p53 and NKX3.1) or dsRNA mediated apoptosis (protein kinase PKR). Mapping of HPC1 to RNASEL and the association of RNASEL mutations with prostate cancer risk provide the justification for these studies. The experiments described in this PROPOSAL describe a previously unexplored area of research that may bring us closer to the eventual goal of understanding a molecular basis for prostate cancer.