Role of the Wnt/β-catenin/TCF-4 signaling pathway in the regulation of livin expression in proliferation and apoptosis of renal cancer cells

Abstract:

Objective：To investigate the relationship between the Wnt/β-catenin/TCF-4 pathway and livin expression in human renal cancer cell line 786-0，and to explore the apoptosis regulation mechanism of this pathway. Methods：786-0 cells were treated with different concentrations of indomethacin. Cell viability was then determined by CCK-8 assay. Flow cytometry was used to determine apoptosis change. The transcriptional changes of β-catenin，TCF-4，caspase-3，and livin were measured by quantitative real-time PCR，while the expression levels of β-catenin，caspase-3，and livin were measured by Western blot. Results：With the increase in the concentration of indomethacin，the cell viability decreased in a dose-response manner（P=0.000）. Flow cytometry showed that the apoptosis rate increased with the increase in the concentration of indomethacin. The apoptosis rates of the 25 μmol/L group，50 μmol/L group，and 100 μmol/L group were （32.07±1.01）%，（40.03±1.95）%，and （72.33±0.02）%，respectively，all showing significant differences compared with those of the control group（P=0.000，0.002，and 0.000，respectively）. Real-time PCR showed that the relative expression levels of β-catenin，TCF-4，and livin decreased significantly（P=0.002，0.000，and 0.000，respectively），while the level of caspase-3 increased significantly（P=0.001）. Western blot revealed that，in the 25 μmol/L group，50 μmol/L group，and 100 μmol/L group，the relative expression levels of β-catenin were 0.568±0.020（P=0.001），0.396±0.030（P=0.000），and 0.142±0.038（P=0.000），respectively；the levels of livin were 0.139±0.016（P=0.005），0.050±0.006（P=0.000），and 0.011±0.001（P=0.000），re－spectively；and the levels of caspase-3 were 0.278±0.035（P=0.046），0.396±0.071（P=0.000），and 0.518±0.015（P=0.000），respectively. Conclusion：Indomethacin-mediated degradation of β-catenin/TCF-4 in renal cancer cells may lead to the tran－scriptional repression of livin and the up-regulation of caspase-3 expression，thereby inducing apoptosis of renal cancer cells.