MicroRNA and colorectal cancer chemoprevention

描述（由申请人提供）：根据美国癌症协会的最新癌症统计报告，结直肠癌仍然是美国癌症死亡的主要原因。因此，仍然存在开发用于治疗和预防结直肠癌的更安全和更有效的药剂的未满足的需求。许多研究报告，非甾体抗炎药（NSAID）舒林酸对家族性腺瘤性息肉病患者的癌前腺瘤治疗非常有效，并在临床前动物模型中显示出有希望的抗癌活性;然而，环氧化酶（考克斯）抑制引起的不良副作用限制了舒林酸用于化学预防的长期使用。我们的前期研究发现，两种非考克斯抑制剂类化合物舒林酸硫酰胺（SSA）和舒林酸苄胺（SBA）对结直肠癌细胞生长的抑制作用优于舒林酸硫醚（SS），提示舒林酸的抗肿瘤活性可能与抑制考克斯不同。在本申请中，我们将针对以下的抗癌活性： SSA和SBA在预防结直肠肿瘤进展和转移中的作用，并着重探讨其作用机制。我们最近的研究结果表明，SS在亚细胞毒性浓度下可以有效地抑制人结肠肿瘤细胞的侵袭，这表明这种药物可能抑制与转移相关的生物学过程。作用机制似乎涉及microRNA（miRNAs），这是一组小的非编码RNA分子，作为基因表达的主要调节因子。SS及其非COX抑制衍生物通过转录抑制因子snail介导的信号通路上调肿瘤抑制miRNA miR-200。鉴于文献记载的促进细胞凋亡和抑制转移的肿瘤抑制作用，我们假设miR-200是介导SSA和SBA预防结直肠癌的非COX抗癌活性的关键因子。提出了三个具体目标来解决这一假设：（1）研究miR-200在体外介导SSA和SBA抗癌活性的机制基础;（2）研究miR-200在体内介导舒林酸抗癌活性中的作用;（3）评估snail/miR-200/E-cadherin与人类结直肠癌进展的临床相关性。该申请是为了回应PA-12-213而提交的，将解决两个研究目标：“确定易导致癌症发生或进展的非编码RNA（ncRNA）靶向的分子途径”和“确定干扰致癌ncRNA加工，靶向选择或相关途径是否会阻止癌症进展”。拟议的研究有可能通过以下方式影响人类健康：1）为正在进行的研究舒林酸预防结直肠癌转移的国家临床试验提供机制依据; 2）评估舒林酸的新型非COX抑制指令，以加速其临床前开发; 3）确定临床试验的新治疗靶点和/或生物标志物。

DESCRIPTION (provided by applicant): According to the latest report of cancer statistics by American Cancer Society, colorectal cancer remains a leading cause of death from cancer in the United States. Therefore, there is still an unmet need to develop safer and more efficacious agents for treatment and prevention of colorectal cancer. Numerous studies report that the nonsteroidal anti-inflammatory drug (NSAID), sulindac is highly effective for the treatment of precancerous adenomas in individuals with familial adenomatous polyposis and shows promising anticancer activity in preclinical animal models; however, the adverse side effects resulting from cyclooxygenase (COX) inhibition limit the long-term use of sulindac for chemoprevention. Our previous studies reported that two non- COX inhibitory derivatives, sulindac sulfide amide (SSA) and sulindac benzylamine (SBA), can inhibit colorectal tumor cell growth with better potency and improved efficacy when compared to sulindac sulfide (SS).These results imply that anticancer activity of sulindac might attribute to other underlying mechanisms distinct from COX inhibition. In this application, we will aim at anticancer activity of SSA and SBA in prevention of colorectal tumor progression and metastasis, and focus on mechanism of action. Our recent results show that SS at sub-cytotoxic concentrations can efficiently inhibit the invasion of human colon tumor cells, which suggest that this drug may inhibit biological processes associated with metastasis. The mechanism of action appears to involve microRNAs (miRNAs), which are a set of small non-coding RNA molecules acting as master regulators of gene expression. A tumor suppressor miRNA, miR-200, was found to be up-regulated by SS and its non-COX inhibitory derivatives through the signaling pathway mediated by the transcriptional repressor snail. Given the documented tumor suppressive roles in promotion of apoptosis and inhibition of metastasis, we hypothesize that miR-200 is a key factor to mediate the non-COX anticancer activity of SSA and SBA for prevention of colorectal cancer. Three specific aims are proposed to address this hypothesis are: (1) to study the mechanistic basis of miR-200 in mediation of anticancer activities of SSA and SBA in vitro; (2) to study the role of miR-200 in mediating anticancer activities of sulindac in vivo; (3) to assess the clinical relevance of snail/miR-200/E-cadherin to human colorectal cancer progression. This application is being submitted in response to PA-12-213 and will address two research objectives: "determine the molecular pathways targeted by non-coding RNAs (ncRNAs) that predispose to cancer initiation or progression" and "determine whether interfering with oncogenic ncRNAs processing, target selection, or associated pathways prevent cancer progression". The proposed studies have the potential to impact human health by: 1) providing a mechanistic rationale in support of an ongoing national clinical trial studying prevention of colorectal cancer metastasis by sulindac; 2) evaluating novel non-COX inhibitory directives of sulindac to accelerate their preclinical development; and 3) identifying new therapeutic targets and/or biomarkers for clinical trials.