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.

国家自然科学基金（No.81973532）；湖南省教育厅科学研究项目（No.19C1610）；南华大学科研基金项目（No.220XNK002）