Involvement of Up-regulation of Death Receptors and Bim in Hispolon-mediated TNF-related Apoptosis-inducing Ligand Sensitization in Human Renal Carcinoma

BACKGROUND: Hispolon has been shown to possess antitumor effects in various cancer cells. However, the underlying mechanisms are not fully understood. In this study, we evaluated the sensitizing effect of hispolon on TNF-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis in human renal carcinoma cells. METHODS: Apoptosis was analyzed by using cell-based cytometer. The mRNA levels were assessed by reverse transcription-PCR. Bax activation was determined by oligomerization and fluorescence-activated cell sorting with Bax-NT monoclonal antibody. The protein expression was measured by Western blotting. RESULTS: Hispolon induced up-regulation of Bim and death receptors expression at the post-translational level. CONCLUSIONS: Hispolon enhanced TRAIL-mediated apoptosis in renal carcinoma cells, but not in normal cells.