Abstract:

Objective To explore the effects and mechanism of bexarotene in combination with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) on apoptosis of leukemic cell line KG1a. Methods KG1a cells at logarithmic growth phase were obtained, and were divided into TRAIL group, bexarotene group, 300 ng/mL TRAIL in combination with bexarotene group and 2.0 μmol/L bexaroten in combination with TRAIL group. Cell apoptosis rate was detected in each group by flow cytometry. Flow cytometry was also employed to determine the apoptosis rates of KG1a cells after treatment with bexarotene and TRAIL in different sequences. The expression of Fas associated death domain-like IL-1 beta converting enzyme inhibitory protein (c-FLIP) was detected by Western blotting. Results There was no significant difference in cell apoptosis rates between TRAIL group and bexarotene group of each concentration (except for bexarotene 2.0 μmol/L) (P>0.05).The cell apoptosis rates of 300 ng/mL TRAIL in combination with bexarotene group and 2.0 μmol/L bexaroten in combination with TRAIL group were significantly higher than those in TRAIL group and bexarotene group of each corresponding concentration (P<0.01). Sequential analysis revealed that bexarotene could reverse the resistance of KG1a cells to TRAIL (P<0.001). Compared with single use of 2.0 μmol/L bexarotene or 300 ng/mL TRAIL, combination use could significantly down-regulated the expression of c-FLIP (P<0.05). Conclusion Bexarotene can significantly enhance the apoptosis of KG1a cells induced by TRAIL, which may be attributed to the down-regulation of c-FLIP expression.

Key words: tumor necrosis factor-related apoptosis-inducing ligand, apoptosis, leukemia