Tseng Chien-Wei, Huang Hsuan-Cheng, Shih Arthur Chun-Chieh, Chang Ya-Ya, Hsu Chung-Cheng, Chang Jen-Yun, Li Wen-Hsiung, Juan Hsueh-Fen
Department of Life Science, Institute of Molecular and Cellular Biology, National Taiwan University, Taipei 106, Taiwan.
Institute of Biomedical Informatics, Center for Systems and Synthetic Biology, National Yang-Ming University, Taipei 112, Taiwan.
Int J Mol Sci. 2012;13(5):6352-6369. doi: 10.3390/ijms13056352. Epub 2012 May 23.
microRNAs (miRNAs) cause mRNA degradation or translation suppression of their target genes. Previous studies have found direct involvement of miRNAs in cancer initiation and progression. Artificial miRNAs, designed to target single or multiple genes of interest, provide a new therapeutic strategy for cancer. This study investigates the anti-tumor effect of a novel artificial miRNA, miR P-27-5p, on breast cancer. In this study, we reveal that miR P-27-5p downregulates the differential gene expressions associated with the protein modification process and regulation of cell cycle in T-47D cells. Introduction of this novel artificial miRNA, miR P-27-5p, into breast cell lines inhibits cell proliferation and induces the first "gap" phase (G1) cell cycle arrest in cancer cell lines but does not affect normal breast cells. We further show that miR P-27-5p targets the 3'-untranslated mRNA region (3'-UTR) of cyclin-dependent kinase 4 (CDK4) and reduces both the mRNA and protein level of CDK4, which in turn, interferes with phosphorylation of the retinoblastoma protein (RB1). Overall, our data suggest that the effects of miR p-27-5p on cell proliferation and G1 cell cycle arrest are through the downregulation of CDK4 and the suppression of RB1 phosphorylation. This study opens avenues for future therapies targeting breast cancer.
微小RNA（miRNA）可导致其靶基因的mRNA降解或翻译抑制。先前的研究发现miRNA直接参与癌症的发生和发展。设计用于靶向单个或多个感兴趣基因的人工miRNA为癌症提供了一种新的治疗策略。本研究调查了一种新型人工miRNA，即miR P-27-5p对乳腺癌的抗肿瘤作用。在本研究中，我们发现miR P-27-5p下调了与T-47D细胞中蛋白质修饰过程和细胞周期调控相关的差异基因表达。将这种新型人工miRNA，即miR P-27-5p引入乳腺癌细胞系可抑制细胞增殖，并在癌细胞系中诱导第一个“间隙”期（G1）细胞周期停滞，但不影响正常乳腺细胞。我们进一步表明，miR P-27-5p靶向细胞周期蛋白依赖性激酶4（CDK4）的3'-非翻译mRNA区域（3'-UTR），并降低CDK4的mRNA和蛋白质水平，进而干扰视网膜母细胞瘤蛋白（RB1）的磷酸化。总体而言，我们的数据表明miR p-27-5p对细胞增殖和G1细胞周期停滞的影响是通过下调CDK4和抑制RB1磷酸化实现的。本研究为未来针对乳腺癌的治疗开辟了道路。
