Functional Genomics Unit, Institute of Genomics and Integrative Biology, Council of Scientific and Industrial Research, Mall Road, Delhi, India.
Cell Mol Life Sci. 2011 Apr;68(8):1415-28. doi: 10.1007/s00018-010-0528-y. Epub 2010 Sep 19.
MicroRNAs (miRNAs) are short ~21-nt non-coding RNA molecules that have been shown to regulate a number of biological processes. Previous reports have shown that overexpression of miR-128 in glioma cells inhibited cell proliferation. Literature also suggests that miR-128 negatively regulates prostate cancer cell invasion. Here, we show that overexpression of hsa-miR-128, a brain-enriched microRNA, induces apoptosis in HEK293T cells as elucidated by apoptosis assay, cell cycle changes, loss of mitochondrial membrane potential and multicaspase assay. By in silico analysis, we identified a putative target site within the 3' untranslated region (UTR) of Bax, a proapoptotic member of the apoptosis pathway. We found that ectopic expression of hsa-miR-128 suppressed a luciferase reporter containing the Bax-3' UTR and reduced the levels of Bax in HEK293T cells. Taken together, our study demonstrates that overexpression of hsa-miR-128 not only induces apoptosis in HEK293T cells but also is an endogenous regulator of Bax protein.
微小 RNA（miRNAs）是一类约 21 个核苷酸的非编码 RNA 分子，已被证明可以调控多种生物学过程。先前的研究表明，在神经胶质瘤细胞中过表达 miR-128 可抑制细胞增殖。文献还表明，miR-128 负调控前列腺癌细胞的侵袭。在这里，我们发现过表达脑高丰度 microRNA hsa-miR-128 通过凋亡检测、细胞周期变化、线粒体膜电位丧失和多半胱氨酸酶检测，诱导 HEK293T 细胞凋亡。通过计算机分析，我们在凋亡途径中促凋亡成员 Bax 的 3'非翻译区（UTR）内鉴定出一个假定的靶位点。我们发现，hsa-miR-128 的异位表达抑制了含有 Bax-3'UTR 的荧光素酶报告基因，并降低了 HEK293T 细胞中 Bax 的水平。综上所述，我们的研究表明，hsa-miR-128 的过表达不仅诱导 HEK293T 细胞凋亡，而且还是 Bax 蛋白的内源性调节剂。
