The Effects And Mechanism Of Combining TRAIL And Curcumin On Lung Adenocarcinoma A549 Cells Apoptosis

Objective: TNF-related apoptosis-inducing ligand (TRAIL) can induce tumorcells apoptosis especially, but normal cells are resistant to it. It has been a newanticancer agent, however the use of TRAIL is limited because some tumor cellsresist to it. By observing the effect of TRAIL and curcumin on the lungadenocarcinoma A549 cells inhibit rates, apoptosis rates and the expression ofthe apoptosis-correlated factors, to explore the new agent that enhance TRAILcausing lung cancer apoptosis, to explain the mechanism of lung cancer cellresisting to TRAIL. METHOD: 1)Absorbing light values of curcumin group/TRAIL group/combination group/control group were determined through MTTmeans on different conditions of concentrations and times, then A549 cellinhibiting rates were calculated. 2) The apoptosis rates of A549 cells whichwere cultured respectively in 20nmol/ml curcumin, 25ng/ml TRAIL, both of themand RPMI 1640 were calculated by Flowcytometry. The caspase9 expression ofeach group was determined by Flowcytometry. The caspase8 and caspase3expression of each group were determined by ApoAlert Caspase colorimetry set.The caspase3 expressions of former three groups added by caspase9 inhibitorwere determined by the same way. The bcl-2/bax expression of each groupwere determined by RT-PCR. 3) Statistics Method: X~2 test or T test with SPSS10.0software. RESULT: 1)The inhibit rates of A549 cells were increasing remarkablyin line with concentration and time of curcumin(P＜0.001). The inhibit rate ofA549 cells cultured with 50ng/ml TRAIL for 48 hours was 4.41%. Thisphenomena suggests that A549 cells reisist to TRAIL. The inhibit rates of A549cells were increasing remarkably by combination of TRAIL and curcumin (P＜0.001). 2) A549 cells apoptosis rate of combination group(64.26%)wasremarkably more than TRAIL group(15.35%)and curcumin group(30.25%)(P＜0.001). 3) The expression of caspase3,8,9 of combination group wasremarkably more than single agent group and control group(P＜0.001).After usingcaspase9 inhibitor, the expression of caspase3 decreased remarkably(P＜0.001).The bcl-2/bax value of groups without curcumin was remarkablymore than groups with curcumin(P＜0.001).CONCLUSION:Lung adeno-carcinoma A549 cells are resistance to TRAIL.Curcumin can modulate theexpression of bcl-2/bax,improve the sensibility of TRAIL, activate caspasefamily and induce lung adenocarcinoma A549 cells apoptosis throughmitochondrion-depended pathway.