Effect and mechanism of transcription elogation factor A (SII) like 7 on invasion and migration of poorly differentiated human gastric cancer cell line BGC823

Objective To explore the effects and mechanism of transcription elogation factor A (SⅡ) like 7 (TCEAL7) on invasion and migration of poorly differentiated human gastric cancer cell line BGC823 in vitro. Methods Real-time quantitative polymerase chain reaction (Real-time PCR) and Western blotting were utilized to detect mRNA and protein expression of TCEAL7 in BGC823 cells and normal gastric mucosal cell line GES-1. TCEAL7 eukaryotic expression vector was designed and transfected into BGC823 cells for 48 h. The methyl thiazol tetrazolium (MTT) assay was applied to test the cell activity affected by GFP-TCEAL7 transfection. The wound assay and Transwell chamber assay were employed to detect the invasion and migration of cells. Real-time PCR and Western blotting were used to detect the mRNA and protein expression of invasion- and migration-related genes. Results Real-time PCR and Western blotting demonstrated that the expression of TCEAL7 was significantly wearker in BGC823 cells (mRNA: 0.280±0.048; protein: 0.181±0.038) than GES-1 cells (mRNA: 0.474±0.062; protein: 0.346±0.057; t=-6.061, P=0.000; t=-5.900, P=0.000). The expression of TCEAL7 was up-regulated significantly in BGC823 cells after GFP-TCEAL7 transfection (1.886±0.326, 1.007±0.262) as compared with control group (0.302±0.053, 0.172±0.030; t=11.748, P=0.000; t=7.756, P=0.000). Result of MTT exhibited that the proliferation inhibition rate increased significantly in BGC823 cells after GFP-TCEAL7 transfection (0.672±0.083) as compared with control group (1.242±0.215) (t=-6.058, P=0.000). Wound assay and Transwell chamber assay revealed that GFP-TCEAL7 transfection induced decreased migration [for transfection group, (53.945±9.952)%; for control group, (81.017±7.208)%] and invasion [for transfection group, (76.333±12.420); for control group, (121.167±11.771)] of cells (t=-5.396, P=0.000; t=-6.418, P=0.000). The results of Real-time PCR and Western blotting showed that the mRNA and protein levels of matrix metalloproteinase (MMP)-7 and MMP-9 were significantly down-regulated by TCEAL7 overexpression, while the mRNA and protein expression levels of TIMP1 and E-cadherin up-regulated significantly. Conclusion Overexpression of TCEAL7 could inhibit invasion and migration of BGC823 cells. Key words: Gastric neoplasms; Transcription elogation factor A (SⅡ) like 7; Invasion; Migration; Gene cloning