The Effect On The Wnt Signaling Pathway Of Tumor Suppressor Gene TSLC1and Its Inhibitory Action To Hepatoma Carcinoma Cell

Wnt signaling pathway is one of important intracellular signaling transduction system, andparticipates in the tumorigenesis, signal transduction, cell cycle control and proliferation, cellmigration and differentiation, cell adhesion etc. It also plays an important role in embryonicdevelopment and cell proliferation. Wnt pathway is highly conserved signal pathway, and itsmembers are high homolog from lower organism Drosophila to mammal.Tumor suppressor in lung cancer1(TSLC1) is a tumor suppressor gene recently discoveredin non-small cell lung cancer. TSLC1plays an important role in cell adhesion, immunesurveillance, cell motility and signal transduction etc. Recent studies showed that expression ofTSLC1is loss or low level in most human cancer cells, which closely correlate with thetumorigenesis, invasion and metastasis. However, the study on molecular mechanism andintracellular signal transduction pathway of TSLC1in liver cancer is unclear and needs to befurther clarified.This study primarily investigated the relationship between tumor suppressor TSLC1and theWnt signal pathway, and the suppression effect to hepatoma cell of TSLC1. The oncolyticadenovirus Ad.sp-E1A(24)-TSLC1was constructed by using the dual-targeted oncolyticadenovirus Ad.sp-E1A(24)to deliver TSLC1gene. The constructed virus was designed withreplacing the endogenous promoter of E1A with tumor-specific survivin promoter (sp), anddeleting the24bp sequence of E1A-CR2region to target Rb signal abnormal tumor. First wedetected the influence of TSLC1on Wnt signal pathway by the luciferase reporter assay,real-time PCR and western blotting analysis. Second, we evaluated the antitumor effect and thesafety on normal cell lines of TSLC1by MTT and Hoechst33342staining assay. Finally, weused the cell scratch assay and transwell small chamber method to detect the effect on livercancer cell migration and invasion of TSLC1.The results indicated that TSLC1expression in hepatoma cell lines is significantly lowercompared with that of normal liver cells, but survivin expression in hepatoma cell lines issignificantly higher compared with that of normal liver cells. MTT assay displayed thatAd.sp-E1A(24)-TSLC1had no obvious toxicity on normal human cells and had a significantkilling effect on hepatocellular carcinoma cells. Moreover, the overexpression of TSLC1can obviously down-regulate the transcriptional activity of TCF4/β-catenin and mRNA and proteinexpression of Wnt target gene cyclin D1and c-myc. In addition TSLC1can also inhibit invasionand migration of hepatocellular carcinoma cells.In conclusion, this study indicated that the TSLC1could down-regulate Wnt signal pathwayand exhibited the significant suppression effect on hepatocellular carcinoma cell growth,migration and invasiveness. The above results would conduce to clarify the new features andpossible mechanisms of TSLC1gene in the development of liver cancer, and lay a foundation forits application in further liver cancer therapy.