[Overexpression of Twist1 promotes tumor invasion in human tongue squamous cell carcinoma cell line Tca8113].

AIM: To construct an eukaryotic expression vector of human Twist1 and investigate the relationship between Twist1 overexpression and tumor invasion in human tongue squamous cell carcinoma cell line Tca8113.

METHODS: Total mRNA isolated from Tca8113 cells were reversely transcribed to cDNA. Human Twist1 was amplified using specific PCR primers and then subcloned into the pcDNA3.1-myc-hisA vector. The fusion expression plasmid was named Myc-Twist1. Myc-Twist1 was transfected into Tca8113 cells and examined by Western blotting. The localization of Twist1 in Tca8113 cells was observed using confocal laser scanning microscopy. E-cadherin promoter activity in response to Myc-Twist1 overexpression was measured by the dual luciferase reporter assay system. Transwell cell migration assay was performed to detect the invasive capacity of Tca8113 cells stably expressing Myc-Twist1.

RESULTS: The fusion protein Myc-Twist1 was successfully constructed into eukaryotic expression vector. Western blotting showed that Myc-Twist1 was stably expressed in Tca8113 cells and it was localized mainly in the nucleus and a little in the cytoplasm. The Twist1 significantly inhibited the E-cadherin promoter activity and enhanced the cell invasion.

CONCLUSION: Twist1 promotes tumor invasion by down-regulating E-cadherin expression in Tca8113 cells.