Small RNA targeted gene activation for the treatment of prostate cancer

描述（由申请人提供）：在美国，前列腺癌是最常见的男性癌症，也是男性癌症死亡的第二大原因。该提案的长期目标是开发基于小RNA的前列腺癌治疗策略。小双链RNA（dsRNA）已被广泛用作小干扰RNA（siRNA）以通过靶向mRNA序列来敲低基因表达，这一现象被称为RNA干扰（RNAi）。最近，我们和其他人发现了一种新的小RNA介导的基因调控机制，其中靶向基因启动子区域的dsRNA分子诱导序列特异性转录基因激活，这种现象称为“RNA诱导的基因激活”（RNAa）和dsRNA分子“小激活RNA”（saRNA）。我们证明了RNAa在基因激活方面是有效的，并且其作用是持久的，这表明RNAa具有很好的治疗作用。我们假设saRNA分子通过靶向激活前列腺癌中的肿瘤抑制基因（TSGs）在体外和体内具有抗肿瘤活性。这一假设将在两个具体目标中得到检验。具体目标#1。鉴定用于TSG激活的功能性saRNA并评估其在培养的人前列腺癌细胞中的抗生长作用。被靶向激活的基因包括（1）负细胞周期调节因子，例如p16、p21、p27和p53，（2）抑制肿瘤细胞侵袭和转移的基因，包括E-钙粘蛋白、KAI 1和CD 44，和（3）促凋亡基因，包括Par-4和胱天蛋白酶-7。将靶向基因启动子的候选saRNA转染到人前列腺癌细胞系LNCaP和PC 3中，然后在mRNA和蛋白质水平上评估靶基因的表达。将进一步评估功能性saRNA的抗生长活性和对细胞周期分布、凋亡、克隆形成、侵袭和迁移的影响。具体目标#2在异种移植人前列腺肿瘤模型中评价saRNA的抗肿瘤活性。将使用人前列腺癌PC-3细胞在无胸腺小鼠中建立异种移植前列腺肿瘤。具有已建立肿瘤的小鼠将通过瘤内注射用功能性saRNA治疗。将saRNA处理的小鼠中的肿瘤生长与用对照saRNA处理的小鼠进行比较。这些研究构成了我们以前工作的逻辑进展。该提案的成功完成将为RNAa的进一步临床试验提供依据。在美国，前列腺癌是最常见的男性癌症，也是男性癌症死亡的第二大原因。目前迫切需要开发新的前列腺癌治疗策略。该项目将研究一种新发现的使用小RNA分子的基因治疗方法的治疗用途。

DESCRIPTION (provided by applicant): In the U.S., prostate cancer is the most common male cancer and the second leading cause of cancer deaths in men. The long-term objective of this proposal is to develop small RNA-based therapeutic strategies for prostate cancer. Small double-stranded RNA (dsRNA) has been widely used as small interfering RNA (siRNA) to knockdown gene expression by targeting mRNA sequences, a phenomenon known as RNA interference (RNAi). Recently we and others identified a new mechanism of small RNA-mediated gene regulation in which dsRNA molecules targeting gene promoter regions induce sequence-specific transcriptional gene activation, a phenomenon termed "RNA-induced gene activation" (RNAa) and the dsRNA molecules "small activating RNAs" (saRNAs). We demonstrated that RNAa is potent in gene activation and its effects are long-lasting, suggesting a promising therapeutic role for RNAa. We hypothesize that saRNA molecules have anti-tumor activity in vitro and in vivo via targeted activation of tumor suppressor genes (TSGs) in prostate cancer. This hypothesis will be tested in two specific aims. Specific Aim #1. Identify functional saRNAs for TSG activation and evaluate their anti-growth effects in cultured human prostate cancer cells. Genes to be targeted for activation include (1) negative cell cycle regulators such as p16, p21, p27 and p53, (2) genes that inhibit tumor cell invasion and metastasis including E-cadherin, KAI1 and CD44, and (3) pro-apoptosis genes including Par-4 and caspase-7. Candidate saRNAs targeting gene promoters will be transfected into human prostate cancer cell lines LNCaP and PC3, and the expression of targeted genes will then be evaluated at both mRNA and protein levels. Functional saRNAs will be further assessed for their anti-growth activity and effects on cell cycle distribution, apoptosis, clonogenicity, invasion and migration. Specific Aim #2. Evaluate saRNA's anti-tumor activity in xenograft human prostate tumor models. Xenograft prostate tumors will be established in athymic mice using human prostate cancer PC-3 cells. Mice with established tumors will be treated with functional saRNAs by intratumoral injections. Tumor growth in saRNA-treated mice will be compared with mice treated with control saRNAs. These studies constitute a logical progression of our previous work. Successful completion of this proposal will provide rationale for further clinical trials of RNAa. In the U.S., prostate cancer is the most common male cancer and the second leading cause of cancer deaths in men. There is an urgent need to develop novel therapeutic strategies for prostate cancer. This project will investigate the therapeutic use of a newly identified method of gene therapy using small RNA molecules.