Cao J-X, Lu Y, Qi J-J, An G-S, Mao Z-B, Jia H-T, Li S-Y, Ni J-H
Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Xue Yuan Road 38, Beijing 100191, People's Republic of China.
1] Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Xue Yuan Road 38, Beijing 100191, People's Republic of China [2] Department of Biochemistry and Molecular Biology, Capital Medical University, You An Men 8, Beijing 100069, People's Republic of China.
Cell Death Dis. 2014 Sep 25;5(9):e1426. doi: 10.1038/cddis.2014.386.
MicroRNAome analyses have shown microRNA-630 (miR-630) to be involved in the regulation of apoptosis. However, its apoptotic role is still debated and its participation in DNA replication is unknown. Here, we demonstrate that miR-630 inhibits cell proliferation by targeting cell-cycle kinase 7 (CDC7) kinase, but maintains the apoptotic balance by targeting multiple activators of apoptosis under genotoxic stress. We identified a novel regulatory mechanism of CDC7 gene expression, in which miR-630 downregulated CDC7 expression by recognizing and binding to four binding sites in CDC7 3'-UTR. We found that miR-630 was highly expressed in A549 and NIH3T3 cells where CDC7 was downregulated, but lower in H1299, MCF7, MDA-MB-231, HeLa and 2BS cells where CDC7 was upregulated. Furthermore, the induction of miR-630 occurred commonly in a variety of human cancer and immortalized cells in response to genotoxic agents. Importantly, downregulation of CDC7 by miR-630 was associated with cisplatin (CIS)-induced inhibitory proliferation in A549 cells. Mechanistically, miR-630 exerted its inhibitory proliferation by blocking CDC7-mediated initiation of DNA synthesis and by inducing G1 arrest, but maintains apoptotic balance under CIS exposure. On the one hand, miR-630 promoted apoptosis by downregulation of CDC7; on the other hand, it reduced apoptosis by downregulating several apoptotic modulators such as PARP3, DDIT4, EP300 and EP300 downstream effector p53, thereby maintaining the apoptotic balance. Our data indicate that miR-630 has a bimodal role in the regulation of apoptosis in response to DNA damage. Our data also support the notion that a certain mRNA can be targeted by several miRNAs, and in particular an miRNA may target a set of mRNAs. These data afford a comprehensive view of microRNA-dependent control of gene expression in the regulation of apoptosis under genotoxic stress.
微小RNA组分析表明，微小RNA-630（miR-630）参与细胞凋亡的调控。然而，其在细胞凋亡中的作用仍存在争议，并且其在DNA复制中的参与情况尚不清楚。在此，我们证明miR-630通过靶向细胞周期激酶7（CDC7）激酶抑制细胞增殖，但在遗传毒性应激下通过靶向多种细胞凋亡激活因子维持细胞凋亡平衡。我们确定了一种新的CDC7基因表达调控机制，其中miR-630通过识别并结合CDC7 3'-UTR中的四个结合位点下调CDC7表达。我们发现，在A549和NIH3T3细胞中miR-630高表达，其中CDC7被下调，但在H1299、MCF7、MDA-MB-231、HeLa和2BS细胞中较低，这些细胞中CDC7上调。此外，在多种人类癌症和永生化细胞中，miR-630的诱导通常发生在对遗传毒性剂的反应中。重要的是，miR-630对CDC7的下调与顺铂（CIS）诱导的A549细胞增殖抑制有关。机制上，miR-630通过阻断CDC7介导的DNA合成起始和诱导G1期阻滞发挥其抑制增殖的作用，但在CIS暴露下维持细胞凋亡平衡。一方面，miR-630通过下调CDC7促进细胞凋亡；另一方面，它通过下调几种细胞凋亡调节因子如PARP3、DDIT4、EP300和EP300下游效应因子p53来减少细胞凋亡，从而维持细胞凋亡平衡。我们的数据表明，miR-630在响应DNA损伤时对细胞凋亡的调控中具有双重作用。我们的数据还支持这样一种观点：某个mRNA可以被几种微小RNA靶向，特别是一种微小RNA可能靶向一组mRNA。这些数据为遗传毒性应激下细胞凋亡调控中微小RNA依赖性基因表达控制提供了全面的观点。
