Determining the mechanistic and therapeutic roles of microRNAs in bladder cancer

描述(申请人提供)：microRNAs(MiRNAs)是~22个核苷酸的非编码RNA，通常通过与目标mRNA的3‘UTR不完全结合而抑制基因，这会导致翻译抑制和mRNA不稳定。在许多癌症中都观察到了miRNA的失调，许多miRNA不仅参与了癌症的发生和发展，而且由于它们针对的是肿瘤抑制基因或癌基因，因此可能具有治疗潜力。膀胱癌通常表现为移行细胞癌(TCC)，是美国第五大常见癌症。MiRNA图谱的初步结果表明，miRNA的错误表达在TCC的发生中具有严重的后果，一些miRNAs可能是肿瘤抑制基因或癌基因。我们的研究还表明，一些沉默的肿瘤抑制基因miRNAs可以通过表观遗传治疗重新激活。此外，我们开发了一个使用CMV启动子的灵活平台，可以从单个工程转录本中恢复多个肿瘤抑制因子miRNAs的表达。这种新型的表达载体可以通过靶向多个癌基因或致癌途径来抑制肿瘤细胞的生长。在这项建议中，基于我们强大的初步结果，我们计划集中在：1)鉴定用于膀胱癌患者诊断和预后的特定miRNAs；2)通过表观遗传治疗重新激活沉默的肿瘤抑制基因miRNAs；3)表征miRNAs在肿瘤发生中的作用，并通过多个miRNA表达载体在癌细胞中重新表达已鉴定的肿瘤抑制基因miRNAs。这些特定目标的完成将为将miRNAs用作膀胱癌患者的诊断和/或预后标记物和治疗靶点的临床应用迈出重要的一步。

DESCRIPTION (provided by applicant): microRNAs (miRNAs) are ~22 nucleotide non-coding RNAs that usually repress genes by imperfectly binding to the 3'UTR of the target mRNA which causes translational repression and mRNA destabilization. miRNA dysregulation has been observed in many cancers and many miRNAs are not only involved in the initiation and progression of cancer but may have therapeutic potential because they target tumor suppressor genes or oncogenes. Bladder cancer, which usually presents as transitional cell carcinoma (TCC), is the fifth most common cancer in the United States. Preliminary results from miRNA profiling indicate that miRNA misexpression has severe consequences in TCC tumorigenesis and some miRNAs may be tumor suppressors or oncogenes. Our study also shows that some silenced tumor suppressor miRNAs can be reactivated by epigenetic treatment. Furthermore, we have developed a flexible platform using the CMV promoter to restore expression of multiple tumor suppressor miRNAs from a single engineered transcript. This novel expression vector can inhibit tumor cell growth by targeting multiple oncogenes or oncogenic pathways. In this proposal, based on our strong preliminary results, we plan to focus on: 1) identifying specific miRNAs for diagnostic and prognostic purposes for bladder cancer patients; 2) reactivating silenced tumor suppressor miRNAs by epigenetic treatment; 3) characterizing the role of miRNAs during tumorigenesis and re-expressing identified tumor suppressor miRNAs in cancer cells with a multiple miRNA expression vector. Completion of these specific aims will provide an important step towards the clinical application of using miRNAs as diagnostic and/or prognostic markers and as therapeutic targets in bladder cancer patients.