Mechanism Of Hydrogen Gas Promoted Apoptosis Of Lung Adenocarcinoma A549 Cells Through XIAP And BIRC3

Objective:Lung cancer is the most common reason of cancer-related death in worldwide.It is an aggressive threat to people’s health.Until now,we already developed several measures to treat lung cancer,such as surgery,radiotherapy and chemotherapy,but the 5 year survival rate is still low,only about 18%.This study describe a new strategy-hydrogen,as a new medical gas,has been found to have effects on a variety of diseases.It affects the activity of signal pathways by regulating the activity and expression of related proteins and thus exerting their biological functions.At present,it is not reported that the effect of hydrogen gas on lung cancer domestic and overseas.Therefore,we designed this experiment to investigate apoptosis of hydrogen gas on the lung cancer A549 cells,and we will test whether there are differences in the expression of XIAP,BIRC3,BAX and caspase-3 in the A549 cell lines with different concentrations of hydrogen.A549 cell suspension was used to make subcutaneous tumor formation in nude mice.Immunohistochemistry was used to verify the expression of XIAP,BIRC3,BAX and caspase-3 in tumor tissues.The survival curves of TCGA database were used to evaluate the correlation between XIAP,BIRC3 and prognosis of patients with lung adenocarcinoma.Methods:1.A549 cells in logarithmic phase were treated by 20%,40%,60% hydrogen gas respectively.Then the apoptosis of different groups were detected by Flow cytometry.2.A549 cells in logarithmic phase were treated by 20%,40%,60% hydrogen gas respectively.The protein expression of XIAP,BIRC3,caspase-3 and BAX were detected by western blot.3.Fourteen nude mice were randomly divided into three groups(control group,hydrogen group and cisplatin group).Lung cancer A549 cells are inoculated subcutaneously in nude mice to form tumors.Hematoxylin and eosin and immunohistochemistry were performed for histopathological analysis and protein expression of XIAP,BIRC3,caspase-3 and BAX.Results1.The results demonstrated that 20%,40%,60% hydrogen gas can significantly induce apoptosis compared with the control group.2.The expression of XIAP and BIRC3 were downregulated in 20%,40%,60% hydrogen group.There was no significant difference in the expression of caspase-3 and BAX in each group.3.The A549 cells of lung cancer are subcutaneously tumorigenic in nude mice,there was no significant statistical difference of tumor volume between control group and hydrogen group.4.The expression of XIAP and BIRC3 in tumor tissue were downregulated in hydrogen group and cisplatin group compared with the control group.There was no significant difference in the expression of caspase-3 and BAX in each group.5.The K-M survival curve of XIAP and BIRC3 in lung adenocarcinoma were obtained from TCGA databases.The low/medium BIRC3 expression patients have more longer survival than the high expression patients.A statistic difference was found in survival between two groups.(P <0.001)Conclusion:1.The effect of hydrogen gas can be attributed to promote apoptosis in A549 cell line.2.Hydrogen gas can down-regulate the expression of XIAP and BIRC3 in vivo and in vitro.There was no significant difference in the expression of caspase-3 and BAX in each group.It is suggested that hydrogen gas may promote the apoptosis of lung cancer A549 cells by reducing the expression of XIAP and BIRC3 protein.