PTTG1促进结肠癌SW480细胞侵袭和迁移的作用机制

目的 研究垂体肿瘤转化基因 1（pituitary tumor transforming gene 1, PTTG1）过表达促进人结肠癌细胞SW480侵袭和迁移作用及其可能机制。方法 采用脂质体转染法将pcDNA3.1(+)-PTTG1及空载pcDNA3.1(+)转染人结肠癌SW480细胞，G418法筛选阳性克隆。Western blot和Real-time PCR法鉴定稳定过表达PTTG1细胞株建立。Transwell小室法检测细胞侵袭和迁移能力，Western blot检测MMP2、MMP9、E-cadherin、Vimentin和Snail的表达。结果 （1）成功获得稳定高表达PTTG1的SW480克隆细胞株PTTG1-SW480；（2）过表达PTTG1基因后，SW480细胞侵袭和迁移能力增强，MMP2和MMP9表达升高，上皮间质转化（epithelial-mesenchymal transition, EMT）标记分子E-cadherin表达降低，Vimentin和Snail的表达升高，差异均有统计学意义（P<0.01）；（3）过表达PTTG1基因后，SW480细胞中PI3K/AKT信号活化增强，使用LY29400干预后，抑制细胞侵袭、迁移和EMT，E-cadherin表达上调、Vimentin和Snail的表达下调，差异均有统计学意义（P<0.01）。结论 PTTG1基因过表达可能通过活化PI3K/AKT信号诱导SW480细胞EMT发生，发挥促进SW480侵袭和迁移作用；提示PTTG1蛋白可能成为结肠癌治疗的一个潜在靶点。

Effect of PTTG1 Expression on Invasion and Migration of Colon Cancer Cell SW480 and Its Possible Mechanism

Objective To investigate the effect of over-expression of pituitary tumor transforming gene 1 (PTTG1) on the invasion and migration of human colon cancer cells SW480 and its possible mechanism. Methods Both pcDNA3.1(+)-PTTG1and pcDNA3.1(+) plasmids were separately transfected into human colon cancer cell line SW480 by liposome transfection method and G418 was used to screen positive clones. Real-time PCR and Western blot were used to asses the stably over-expressed PTTG1 in PTTG1-SW480. The abilities of migration and invasion of PTTG1-SW480 cells were assayed by Transwell chambers and Western blot was used to detect the expression of MMP2, MMP9, E-cadherin, Vimentin and Snail. Results (1) The cloned cells PTTG1-SW480 with PTTG1 over-expression were successfully obtained; (2) After PTTG1 overexpression, the abilities of migration and invasion of SW480 cells were enhanced, the expression of MMP2 and MMP9 were up-regulated, Vimentin and Snail expression were up-regulated, and E-cadherin expression was down-regulated (all P<0.01); (3) The signaling pathway of PI3K/AKT activation was enhanced in PTTG1-SW480 cells. Interfering with LY29400, the abilities of migration and invasion and EMT of PTTG1- SW480 cells were prevented, the expression of E-cadherin was up-regulated and Vimentin and Snail expression were down-regulated (all P<0.01). Conclusion PTTG1 over-expression may promote SW480 cells migration and invasion through activating PI3K/AKT pathway to induce EMT. PTTG1 may become a potential target for colon cancer treatment.