mag-1对肿瘤细胞迁移、粘附和侵袭能力的影响及其作用机制的研究

　　贾海泉

　　【摘要】目的：研究mag-1(即LPAAT-θ)对肿瘤细胞转移相关的生物学行为的影响及其作用机制。方法：通过Western-blot检测mag-1在高低转移肿瘤细胞株中的表达水平；将mag-1真核表达载体转染低转移肿瘤细胞PLA801C与MCF-7中并筛选出稳定克隆；利用获得的稳定转染细胞株观察过表达mag-1对肿瘤细胞生物学行为的影响；构建针对mag-1的siRNA表达载体，并将其稳定转染高转移肿瘤细胞PLA01D，进一步观察mag-1对肿瘤细胞迁移、粘附和侵袭能力的影响；明确mag-1在细胞中的定位，观察过表达mag-1对某些已知的肿瘤转移相关分子表达水平及细胞内信号通路活化的影响。结果：mag-1在三对高低转移肿瘤细胞株间的表达水平均存在差异，在高转移细胞株中表达水平较高，尤其在PLA801D与PLA801C以及MDA-MB-231与MCF-7间的表达差异更为显著；过表达mag-1对细胞的增殖没有明显的影响，但对细胞的迁移、粘附及侵袭能力均有不同程度的促进作用；siRNA干涉mag-1的表达则降低了细胞的迁移、粘附及侵袭能力；mag-1主要定位于胞浆， mag-1对某些已知的肿瘤转移相关基因的表达水平没有影响，mag-1能够促进细胞中mTOR信号通路的活化；特异性抑制mTOR能够部分逆转mag-1对肿瘤细胞的迁移、粘附及侵袭能力的促进作用。结论：mag-1能够促进肿瘤细胞的迁移粘附和侵袭能力，mTOR信号通路的活化在mag-1影响肿瘤细胞转移表型中发挥重要作用。

　　Investigation of the effect and the mechanism of mag-1 on the migration adhesion and invison of tumor cells

　　[Abstract] Objective: To investigate the effect and the mechanism of mag-1 (i.e. LPAAT-θ)on the metastasis associated behavior of tumor cells. Methods: The differential expression of mag-1 between highly and poorly metastatic sublines of tumor cells was determined through Western-blot; Mag-1 expression vector was transfected into the poorly metastatic tumor cells PLA801C and MCF-7 and the population of cells that express exogenous mag-1 stably was selected; With the stably transfected cell lines，we observed the effect of mag-1 on tumor cells behavior；siRNA expression vectors that aim at mag-1 was constructed and transfected into the highly metastatic tumor cells PLA801D stably; With the population cells that mag-1 was inhibited most efficiently, we assayed the effect of mag-1 on migration, adhesion and invasion of tumor cells furtherly; we determined the chromosomal localization of mag-1 and investigated the effect of mag-1 on the expression level of some identified metastasis associated genes and the activity of signal pathways in cells. Results: mag-1 expresses differentially in three pairs of highly and poorly metastatic cellines and the level of mag-1 expression is high in highly metastatic cellines; Especially between PLA801D and PLA801C, between MDA-MB-231 and MCF-7 the differentiation was more apparent; The proliferation of PLA801C and MCF-7 transfected with mag-1 did not change，but their ability of migration，adhesion and invasion increased as compared with cells transfected with control vector; The cells whose mag-1 was interfered showed a lower level of migrate, adhesive and invasive behavior; The expression product of mag-1 mainly localized in cytoplasm; Enhanced mag-1 expression does not alter the expression level of certain metastasis associated genes but mag-1 overexpression induced the activation of mTOR signal pathway. The enhanced migration, adhesion and invasion of PLA801C resulting from mag-1 overexpression were reversed partially when mTOR was Specially inhibited. Conclusion: mag-1 promotes tumor cell migration, adhesion and invasion and the activation of the mTOR pathway plays an essential role in the promoting effect of mag-1 on tumor cells metastatic phenotype.