Effects of hyperbaric oxygenation combined with gemcitabine on the proliferation and apoptosis of lung cancer cells A549 and its related mechanism

Abstract

Objective To investigate the effects of hyperbaric oxygenation (HBO) combined with gemcitabine (GEM) on the proliferation and apoptosis of human lung cancer cells A549 and its related molecular mechanism. Methods Following in vitro culture of lung cancer A549 cells, the subjects were divided into the control group, the GEM group, the HBO group and the HBO+ GEM group. CCK-8 was used to detect the inhibitive effects of the combined use of HBO and GEM on the proliferation of lung cancer cell A549. Flow cytometry was performed to detect apoptosis of A549, and Western blotting was used to determine the expression levels of apoptosis-related proteins and signaling pathway-associated proteins. Results The A549 proliferation capacity of the GEM group was significantly lower than that of the blank control and HBO groups (P<0.05), while that of the HBO+ GEM group was significantly lower than that of the GEM group(P<0.05). The A549 apoptosis rate of the GEM group was obviously higher than that of the blank control and HBO groups (P<0.05), while that of the HBO+ GEM group was significantly higher than that of the GEM group(P<0.05). The expression levels of Bcl-2 and Caspase-9 in the GEM group decreased, while the expression levels of Cyt-c, Bax and caspase-3 elevated, and Bax/Bcl-2 ratio also elevated (all P<0.01). Combined treatment with HBO and GEM further regulate the expression of apoptosis-related protein and decrease the expression of P-gp protein. As compared with the GEM group, statistical significance could be found (P<0.05). The p-JNK expression level in the GEM group was up-regulated, while the expression level of p-STAT3 was not significant (P<0.01). The p-STAT3 expression level in the HBO+ GEM group was down-regulated, and the p-JNK expression level was up-regulated. Statistical significance could also be noted when compared with the GEM group (P<0.05). Conclusion HBO could effectively enhance the inhibitive effect of GEM on the proliferation of A549 cells, induce the apoptosis of A549 cells by GEM, and furthermore reduce drug resistance of A549 cells to GEM, the mechanism of which might be related to the regulation of JNK/STAT3 signaling pathway. Key words: Hyperbaric oxygen; Lung cancer; A549 cell; Gemcitabine; JNK/STAT3 signaling pathway