Department of Biology, York University, 4700 Keel Street, Toronto ONM3J1P3, Canada.
J Cell Sci. 2011 Feb 1;124(Pt 3):359-68. doi: 10.1242/jcs.072223. Epub 2011 Jan 11.
MicroRNAs (miRNAs) are small noncoding RNAs that have important roles in gene regulation. We have previously reported that activin receptor-like kinase 7 (ALK7) and its ligand, Nodal, induce apoptosis in human epithelial ovarian cancer cells. In this study, we examined the regulation of ALK7 by miRNAs and demonstrate that miR-376c targets ALK7. Ectopic expression of miR-376c significantly increased cell proliferation and survival, enhanced spheroid formation and blocked Nodal-induced apoptosis. Interestingly, overexpression of miR-376c blocked cisplatin-induced cell death, whereas anti-miR-376c enhanced the effect of cisplatin. These effects of miR-376c were partially compensated by the overexpression of ALK7. Moreover, in serous carcinoma samples taken from ovarian cancer patients who responded well to chemotherapy, strong ALK7 staining and low miR-376c expression was detected. By contrast, ALK7 expression was weak and miR-376c levels were high in samples from patients who responded poorly to chemotherapy. Finally, treatment with cisplatin led to an increase in expression of mRNA encoding Nodal and ALK7 but a decrease in miR-376c levels. Taken together, these results demonstrate that the Nodal-ALK7 pathway is involved in cisplatin-induced cell death in ovarian cancer cells and that miR-376c enhances proliferation, survival and chemoresistance by targeting, at least in part, ALK7.
微小 RNA(miRNAs)是一类在基因调控中发挥重要作用的小非编码 RNA。我们之前曾报道过激活素受体样激酶 7(ALK7)及其配体 Nodal 可诱导人上皮性卵巢癌细胞凋亡。在这项研究中,我们研究了 miRNAs 对 ALK7 的调控作用,并证实 miR-376c 靶向 ALK7。miR-376c 的异位表达显著增加了细胞增殖和存活,增强了球体形成并阻断了 Nodal 诱导的凋亡。有趣的是,miR-376c 的过表达阻断了顺铂诱导的细胞死亡,而抗 miR-376c 则增强了顺铂的作用。miR-376c 的这些作用部分被 ALK7 的过表达所补偿。此外,在对化疗反应良好的卵巢癌患者的浆液性腺癌样本中,检测到 ALK7 染色强烈且 miR-376c 表达水平低。相比之下,在对化疗反应不佳的患者样本中,ALK7 表达较弱,miR-376c 水平较高。最后,用顺铂处理导致编码 Nodal 和 ALK7 的 mRNA 表达增加,但 miR-376c 水平降低。总之,这些结果表明 Nodal-ALK7 通路参与了顺铂诱导的卵巢癌细胞死亡,而 miR-376c 通过靶向 ALK7 至少部分增强了增殖、存活和化疗耐药性。