The Research Of 3-BrPA Reversing The Drug Resistance Of Human Lung Adenocarcinoma Cell Line

BackgroundCancer is a disease which cannot be cured bringing heavy economic burden to the society in both the developed and developing countries.Because of the pollution and the influence of smoking,lung cancer has become almost the leading cause of cancer death among males,and the case fatality rate of lung cancer has surpassed breast cancer among women in developed countries [1].It is well-known that the most effective treatment of lung cancer is surgical resection,but the vast majority of patients diagnosed very late,therefore the more effective treatments for the vast majority of patients who have lost the operation chance is chemotherapy[2].The standard scheme of lung cancer chemotherapy is platinum containing regimens,however,the therapeutic effect of these solutions is not satisfactory,the main reason is cisplatin resistance.After cisplatin resistance,the expression of multi-drug resistance protein P-gp has increased,which changes the discharge and intake of cisplatin,thereby reducing the cell content,makes it cannot achieve the effective concentration [3].In the 20 th century,Warburg O et al[4-6] found that tumor cells use glycolysis for energy generation to maintain survival even the oxygen is enough,a phenomenon known as the “Warburg effect” [7].XU RH and Pelicano H et al had confirmed that blocking the glycolytic pathway can kill tumer cells with MDR phenotype and inhibit the production of ATP.Tumer cells with MDR phenotype still remained very sensitive to 3-BrPA and the combination of 3-BrPA with doxorubicin,vincristine,or ara-C enhanced the effect of every drug against the drug-resistant cells(HL-60/AR)[8].Therefore,3-BrPA used as a kind of glycolysis inhibitor,bringing a new way of thinking for the MDR research to the cancer community.This research intends to explore whether the combined use of 3-BrPA can reverse the resistance of cisplatin-resistant lung adenocarcinoma cells and discuss its potential mechanism.ObjectiveThe aim of this research is to preliminarily explore the reversal effect of 3-BrPA on multidrug resistance of lung cancer cell line A549/DDP and discuss its potential mechanism.Methods1.The CCK-8 kits was used to detect the anti-proliferative effect of 3-BrPA to A549 / DDP cells,and thus the best resistant reverse concentration of 3-BrPA was calculated.2.The half maximal inhibitory concentrations(IC50)of cisplatin for A549 cells,A549 / DDP cells and A549 / DDP cells combinated with 3-BrPA were detected by CCK-8 kits respectively,and thus the resistant multiples of A549 / DDP cells,the resistant reverse ratio and relative reversal efficiency of 3-BrPA were calculated.3.The expression of P-gp on A549 cells,A549 / DDP cells and A549 / DDP cells combinated with 3-BrPA were detected by Western blot,and thus the effect of 3-BrPA to the P-gp expression was observed.4.The mean fluorescence intensity(MFI)of rhodamine 123 in A549 / DDP cells combinated with different concentrations 3-BrPA were detected by flow cytometry,and thus the effect of 3-BrPA to the P-gp function was observed.Results1.3-BrPA can inhibit the growth of A549 / DDP cells,and theinhibition increases with increasing time and dose(P < 0.05),and thus the best resistant reverse concentration of 3-BrPA was 5ug/ml.2.The IC50 of cisplatin of A549 cells and A549 / DDP cells were6.714ug/ml and 38.99 ug/ml,the IC50 of cisplatin combination with 3-BrPA of A549 / DDP cells was 12.86 ug/ml,and thus the resistance index of A549 / DDP cells was 5.81.The reversal index of 3-BrPA on the resistance of cisplatin was 3.03 and the relative reversal efficiency was 81%.3.After adding 3-BrPA 48 hours,western blot tested the expressionof P-gp overexpression of A549 / DDP cells was significantly lower than before.4.The mean fluorescence intensity(MFI)of A549 / DDP cellscombination with 3-BrPA increased with increasing concentration of 3-BrPA.Conclusions1.3-BrPA can inhibit the growth of A549 / DDP cell in a time-and dose-dependent manner.2.3-BrPA can reverse the resistance of cisplatin of human lung adenocarcinoma A549 / DDP cells.3.3-BrPA can reverse the resistance of cisplatin of A549 / DDP cells by inhibiting the expression of P-gp and reducing the function of P-gp.