DJ-1过表达通过PTEN/Akt通路促进人胃癌MGC803细胞的增殖、迁移、侵袭与上皮间质转化

DJ-1 over-expression promotes proliferation,migration,invasion and epithelial mesenchymal transformation of human gastric cancer MGC803 cells through PTEN/Akt pathway

目的:探讨DJ-1基因过表达对人胃癌MGC803细胞增殖、迁移、侵袭与上皮间质转化(EMT)的影响及其机制。方法:利用基因转染技术构建DJ-1基因过表达MGC803细胞,实验分为MGC803、空载体和DJ-1过表达组。采用MTT、平板克隆形成、细胞划痕和Transwell实验分别检测DJ-1过表达对MGC803细胞增殖、克隆形成、迁移与侵袭的影响;qPCR和WB法检测DJ-1过表达对各组细胞DJ-1、PTEN、Akt、p-Akt、Snail、vimentin、E-cadherin、MMP-9与TIMP-3表达的影响,相差显微镜下观察MGC803细胞形态学的变化。裸鼠荷瘤实验检测DJ-1过表达对MGC803细胞移植瘤体内生长的影响。结果:成功构建DJ-1基因稳定过表达的MGC803细胞。与MGC803组和空载体组比较,DJ-1过表达组细胞的增殖能力与克隆形成数均显著增加(均P<0.05),细胞迁移距离明显增加、划痕距离明显缩短(均P<0.05),迁移与侵袭细胞数显著增多(均P<0.05),DJ-1 mRNA与蛋白表达明显上调、PTEN mRNA与蛋白表达下调(均P<0.05),Akt总蛋白各组比较无明显差异(均P>0.05),p-Akt蛋白表达明显上调(P<0.05),Snail、vimentin与MMP-9表达上调、E-cadherin与TIMP-3表达下调(均P<0.05)。相差显微镜下见长梭形细胞数目增多,圆形与椭圆形细胞减少,异型性更为明显。荷瘤裸鼠体内实验结果表明,与MGC803组相比较,DJ-1过表达组MGC803细胞移植瘤生长速度明显加快、移植瘤质量显著增加(均P<0.05)。结论:DJ-1过表达可通过PTEN/Akt通路在体内外抑制MGC803细胞的增殖、迁移、侵袭与EMT。

Objective:To investigate the effects of DJ-1 gene over-expression on proliferation,migration,invasion and epithelial-mesenchymal transformation(EMT)of human gastric cancer MGC803 cells and the underlying mechanism.Methods:MGC803 cells with DJ-1 over-expression were constructed by gene transfection technology.Three groups of cells,namely MGC803 group,empty vector group,and DJ-1 over-expression group were set.The effects of DJ-1 gene over-expression on proliferation,clone formation,migration and invasion of MGC803 cells were detected by MTT,plate cloning assay,cell scratch assay and Transwell invasion assay,respectively.The effects of DJ-1 over-expression on the expression levels of DJ-1,PTEN,Akt,p-Akt,Snail,vimentin,E-cadherin,MMP-9 and TIMP-3 were detected by qPCR and Western blot.The morphological changes of MGC803 cells were observed by phase contrast microscope.The effect of DJ-1 over-expression on the growth of MGC803 cell transplanted tumor in vivo was detected in nude mice.Results:MGC803 cells with stable DJ-1 over-expression were constructed successfully.The proliferation ability and number of clones in DJ-1 over-expression group were significantly increased compared with those in MGC803 cell group and empty vector group(all P<0.05);the cell migration distance was significantly increased while the scratch distance was significantly shortened in DJ-1 over-expression group compared with those in MGC803 cell group and empty vector group(all P<0.05);and the migrated and invaded cells of DJ-1 over-expression group were significantly more than those of MGC803 group and empty vector group(all P<0.05).Moreover,the expression of DJ-1 was significantly up-regulated while the expression of PTEN was significantly down-regulated at both the mRNA and protein levels in the DJ-1 over-expression group compared with those in MGC803 group and empty vector group(both P<0.05).There was no significant difference in total Akt protein among all groups(P>0.05),but the expression of p-Akt protein in DJ-1 over-expression group was significantly up-regulated compared with MGC803 group and empty vector group(all P<0.05).In addition,Snail,vimentin and MMP-9 were up-regulated in DJ-1 over-expression group,while E-cadherin and TIMP-3 were down-regulated(all P<0.05).Phase contrast microscopy showed that the number of long spindle cells increased while the number of round and oval cells decreased,and the atypia was more obvious in the DJ-1 over-expression group.In vivo experiments showed that the growth rate of transplanted tumor in DJ-1 over-expression group was significantly accelerated,and the weight of transplanted tumor was significantly increased(both P<0.05)as compared with MGC803 group.Conclusion:DJ-1 over-expression can inhibit the proliferation,migration,invasion and EMT of MGC803 cells both in vitro and in vivo through PTEN/Akt pathway.