上调微小RNA-520a对胃癌细胞恶性生物学行为和放射增敏性的影响及相关机制

Effect and related mechanism of microRNA-520 a up-regulation on malignant biological behaviors and enhanced radiosensitivity in gastric cancer cells

目的探讨上调微小RNA-520a(miR-520a)对胃癌细胞恶性生物学行为和放射增敏性的影响及相关机制。方法将胃癌MGC-803细胞分为空白组、上调组、下调组,空白组加入常规细胞培养液,下调组给予转染p-Genesil,上调组给予转染p-Genesil-miR-520a。鉴定各组细胞转染情况,并检测细胞增殖、凋亡、迁移、侵袭能力以及Janus激酶3(JAK3)/信号转导及转录激活因子3(STAT3)信号通路蛋白表达量。各组细胞在转染结束后,接受一定剂量的X线照射,观察细胞集落形成情况,并计算平均致死量(D0)、2 Gy剂量X线照射下的细胞存活分数(SF2)和放射增敏比(SER)。结果转染48 h后,上调组miR-520a表达量高于空白组,下调组miR-520a表达量低于空白组及上调组(均P<0.05)。稳定转染后24 h、48 h、72 h,上调组细胞增殖率低于空白组及下调组,下调组细胞增殖率高于空白组;72 h后,上调组及下调组细胞凋亡率均高于空白组,且上调组高于下调组(均P<0.05)。上调组细胞迁移、侵袭数少于空白组及下调组,但下调组细胞迁移、侵袭数多于空白组(均P<0.05)。上调组SF2值、D0值和SER大于空白组及下调组,下调组SF2值、D0值和SER小于空白组(均P<0.05)。上调组JAK3、STAT3、磷酸化JAK3、磷酸化STAT3蛋白表达量均低于空白组及下调组,下调组JAK3、STAT3、磷酸化JAK3、磷酸化STAT3蛋白表达量均高于空白组(均P<0.05)。结论上调miR-520a表达水平可以抑制胃癌细胞增殖、迁移、侵袭,促进细胞凋亡,并可增强细胞的放射增敏性,其可能通过影响JAK3/STAT3信号通路的表达发挥作用。

Objective To explore the effect and related mechanisms of microRNA-520a(miR-520a)up-regulation on malignant biological behaviors and enhanced radiosensitivity in gastric cancer cells.Methods Gastric cancer MGC-803 cells were divided into blank group,up-regulation group and down-regulation group.The blank group was added with conventional cell culture medium,the down-regulation group was transfected with p-Genesil,and the up-regulation group was transfected with p-Genesil-miR-520a.The conditions of cell transfection were checked in each group;besides,the abilities of cell proliferation,apoptosis,migration,and invasion,as well as the protein expression of Janus kinase 3(JAK3)/signal transducer and activator of transcription 3(STAT3)signaling pathway,were detected in each group.After the end of the transfection,cells in each group received an X-ray irradiation at certain doses,and the status of cell colony forming was observed;in addition,the mean fatality dose(D0),cell survival fraction under the X-ray irradiation at a dose of 2 Gy(SF2)and radiosensitivity enhancement ratio(SER)were calculated.Results After 48 hours of the transfection,the up-regulation group exhibited higher miR-520a expression than the blank group,and the down-regulation group exhibited lower miR-520a expression than the blank and up-regulation groups(all P<0.05).Twenty-four,48 and 72 hours after the stable transfection,the up-regulation group reported lower rates of cell proliferation than the blank and down-regulation groups,and the down-regulation group reported higher rates of cell proliferation than the blank group;after 72 hours,the up-regulation and down-regulation groups exhibited higher apoptosis rates than the blank group,in terms of which the up-regulation group was higher than the down-regulation group(all P<0.05).The numbers of cell migration and invasion were fewer in the up-regulation group than in the blank and down-regulation groups,but the numbers of cell migration and invasion in the down-regulation group were more than those in the blank group(all P<0.05).The up-regulation group had increased SF2 value,D0 value and SER than the blank and down-regulation groups,and the down-regulation group had decreased SF2 value,D0 value and SER than the blank group(all P<0.05).The expression of JAK3,STAT3,phosphorylated JAK3,and phosphorylated STAT3 proteins was lower in the up-regulation group than in the blank and down-regulation groups,and the expression of JAK3,STAT3,phosphorylated JAK3,and phosphorylated STAT3 proteins was higher in the down-regulation group than in the blank group(all P<0.05).Conclusion Up-regulation of miR-520a expression level can inhibit the proliferation,migration,and invasion of gastric cancer cells,promote apoptosis,and increase the enhanced radiosensitivity of the cells,which may play its role by affecting the expression of the JAK3/STAT3 signaling pathway.