mir-29 regulates Mcl-1 protein expression and apoptosis
mir-29 regulates Mcl-1 protein expression and apoptosis
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DOI：
10.1038/sj.onc.1210436
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发表时间：
2007-09-13
期刊：
影响因子：
8
通讯作者：
Gores, G. J.
中科院分区：
文献类型：
--
作者：
Mott, J. L.;Kobayashi, S.;Gores, G. J.
抗凋亡Bcl-2家族成员Mcl-1的细胞表达受到严格调控。最近，Bcl-2的表达被证明是由microRNA，小的内源性RNA分子，通过与信使RNA的序列特异性相互作用来调节蛋白质的表达。以此类推，我们推断Mcl-1的表达也可能受到microRNA的调控。我们选择人永生化的，但非恶性的，H69胆管细胞和恶性KMCH胆管癌细胞系进行这些研究，因为Mcl-1在恶性表型细胞中失调。通过计算机分析，我们确定了一个假定的目标网站在Mcl-1 mRNA的mir-29家族，并发现mir-29 b是高表达的胆管细胞。有趣的是，mir-29 b在恶性细胞中下调，与Mcl-1蛋白上调一致。在KMCH细胞中，mir-29 b的表达增强降低了Mcl-1蛋白的表达。这种作用是直接的，因为mir-29 b负调节基于Mcl-130非翻译区（UTR）的报告构建体的表达。mir-29 b的表达降低了Mcl-1细胞蛋白水平，并使癌细胞对肿瘤坏死因子相关凋亡诱导配体（TRAIL）的细胞毒性敏感。用mir-29 b的锁核酸拮抗剂转染非恶性细胞（表达高水平的mir-29）增加了Mcl-1水平并减少了TRAIL介导的凋亡。因此，mir-29是Mcl-1蛋白表达的内源性调节剂，从而是细胞凋亡的内源性调节剂。
Cellular expression of Mcl-1, an anti-apoptotic Bcl-2 family member, is tightly regulated. Recently, Bcl-2 expression was shown to be regulated by microRNAs, small endogenous RNA molecules that regulate protein expression through sequence-specific interaction with messenger RNA. By analogy, we reasoned that Mcl-1 expression may also be regulated by microRNAs. We chose human immortalized, but non-malignant, H69 cholangiocyte and malignant KMCH cholangiocarcinoma cell lines for these studies, because Mcl-1 is dysregulated in cells with the malignant phenotype. By in silico analysis, we identified a putative target site in the Mcl-1 mRNA for the mir-29 family, and found that mir-29b was highly expressed in cholangiocytes. Interestingly, mir-29b was downregulated in malignant cells, consistent with Mcl-1 protein upregulation. Enforced mir-29b expression reduced Mcl-1 protein expression in KMCH cells. This effect was direct, as mir-29b negatively regulated the expression of an Mcl-1 30 untranslated region (UTR)based reporter construct. Enforced mir-29b expression reduced Mcl-1 cellular protein levels and sensitized the cancer cells to tumor necrosis factor-related apoptosis-inducing ligand ( TRAIL) cytotoxicity. Transfection of non-malignant cells ( that express high levels of mir-29) with a locked-nucleic acid antagonist of mir-29b increased Mcl-1 levels and reduced TRAIL-mediated apoptosis. Thus mir-29 is an endogenous regulator of Mcl-1 protein expression, and thereby, apoptosis.