MTERF2对人子宫颈癌HeLa细胞线粒体氧化磷酸化活性的影响

Effect of MTERF2 on Mitochondrial Oxidative Phosphorylation Activity in Human Cervical Cancer HeLa Cells

目的探究过表达或下调线粒体转录终止因子2(MTERF2)基因对人子宫颈癌HeLa细胞线粒体氧化磷酸化活性的影响。方法将人子宫颈癌HeLa细胞分为6组:空白对照组未转染HeLa细胞,阴性对照1和2组分别转染p3×FLAG-CMV-14和pSi-NK,实验1、2和3组分别转染pCMV-MTERF2-FLAG、pSi-MTERF2-1和pSi-MTERF2-2。比较MTERF2蛋白在各组HeLa细胞中的表达情况,并分别检测各组线粒体呼吸链复合体Ⅰ～Ⅴ酶活性、线粒体呼吸控制率(RCR)、线粒体跨膜电位、细胞内ATP含量以及线粒体活性氧(ROS)水平的变化。结果实验1组MTERF2蛋白的表达比空白对照组高,实验2和3组MTERF2蛋白的表达水平比空白对照组低(P<0.01)。与阴性对照2组比较,实验1组线粒体呼吸链复合体Ⅰ、Ⅲ、Ⅳ、Ⅴ相对酶活性以及线粒体跨膜电位下降(P<0.01,P<0.05),线粒体ROS水平升高(P<0.01)。与空白对照组比较,实验1组的线粒体RCR和细胞内ATP含量下降(P<0.01)。而实验2和3组上述指标与空白对照组或阴性对照2组比较差异均无统计学意义(P>0.05)。结论过表达MTERF2基因能显著抑制子宫颈癌HeLa细胞线粒体氧化磷酸化活性,下调MTERF2基因对线粒体氧化磷酸化活性无显著影响。

Objective To investigate effect of overexpression or downregulation of mitochondrial transcription termination factor 2 (MTERF2) gene on mitochondrial oxidative phosphorylation activity in human cervical cancer HeLa cells. Methods Human cervical cancer HeLa cells were divided into 6 groups: blank control group without transfection of HeLa cells, negative control group 1 transfected p3×FLAG-CMV-14, negative control group 2 transfected pSi-NK, and experimental group 1, 2 and 3 transfected pCMV-MTERF2-FLAG, pSi-MTERF2-1 and pSi-MTERF2-2 respectively. Expressions of MTERF2 protein in HeLa cells were compared, and enzymatic activities, mitochondrial respiratory control rates (RCR), mitochondrial transmembrane potential, intracellular adenosine triphosphate (ATP) contents and changes of mitochondrial reactive oxygen species (ROS) of mitochondrial respiratory chain complexes I-V in all groups were detected. Results Expression of MTERF2 protein in experimental group 1 was higher than that in blank control group, and expressions of MTERF2 protein in experimental group 2 and 3 were lower than that in blank control group ( P <0.01). Compared with those in negative control group 2, relative enzyme activities of mitochondrial respiratory chain complexes I, III, IV and V and mitochondrial transmembrane potential were decreased ( P <0.01, P <0.05), while mitochondrial ROS level was increased in experimental group 1 ( P <0.01). Compared with those in blank control group, contents of mitochondrial RCR and intracellular ATP were decreased in experimental group 1 ( P <0.01). There were no significant differences in the above indexes between experimental group 2 and 3 with blank control group or negative control group 2 ( P >0.05). Conclusion Overexpression of MTERF2 gene may significantly inhibit mitochondrial oxidative phosphorylation activity in cervical cancer HeLa cells, while downregulation of MTERF2 gene has no significant effect on mitochondrial oxidative phosphorylation activity.