The Supplement Of Extrinsic Folate On The Efficacy Of Pemetrexed In Inducing The Apoptosis Of Human Lung Adenocarcinoma A549 Cell

Objective To investigate the inhibition effect ofpelnetrexed,a multitargeted antifolate,on human adenocarcinoma A549 cell and normal peripheral blood mononuclear cell(PBMC) and to unravel the influence of extrinsic folate supplement on-the apoptosis induced by pemetrexed in A549 cell and PBMC groups.Method The proliferation capacity of A549 cell and normal PBMC was observed by MTT method after the two cell groups were treated by different concentration gradient(0.0001,0.001,0.01,0.1,1,10,100,1000μg/ml)ofpemetrexed for 24 hours in vitro.The study was repeated 24 hours after pemetrexed was eliminated from the culture medium.We also observed the supplement of different concentration titres of extrinsic folate(0,3,9,27,81nm/L) in inhibiting the cytotoxic effect of pemetrexed on A549 cell and PBMC.In addition,the impact of extrinsic folate on the apoptosis rate of A549 cell and normal PBMC was also investigated by flow cytometry.Result 1) After A549 cell and normal PBMC group were cultured with pemetrexed for 24 hours,we found the OD value decreased correspondingly in A549 cell group and decreased even greater in normal PBMC group with the concentration of pemetrexed increasing from 0.0001μg/ml to 0.1μg/ml for A549 cell group and from 0.0001μg/ml to 1μg/ml for normal PBMC group.The IC50 of A549 cell group was 1.45±0.60,with statistical difference from IC50 in the normal PBMC group,which was 0.03±0.01.After both cell groups were cultured for another 24 hours upon eliminating pemetrexed from culture medium, decreasing of OD value could still be observed,which is negatively correlated with the pre-treated concentration of pemetrexed in PBMC group but not in A549 cell group.The IC50 of A549 cell group and normal PBMC group were 3.13±0.86 and 0.52±0.33 respectively with significant statistical difference(P＜0.05) from the IC50 previously.2) The IC50 of A549 cell group and PBMC group treated by pemetrexed was elevated with the increasing of the concentration of extrinsic folate supplement(0,3,9,27, 81nm/L).There was significant statistical difference(P＜0.05 ) in IC50 upon different concentration treatment of extrinsic folate in both cell groups.3) Using 0.1μg/ml as the final concentration of pemetrexed in the treatment,we found that with the increase of supplement of extrinsic folate,it resulted in a decrease of apoptotic rate of A549 cell group and nomrmal PBMC group.Significant statistical difference was found in the apoptotic rate of groups treated by different concentrations of extrinsic folate in both A549 cell and normal PBMC.Conclusion 1) Pemetrexed could both inhibite the growth of A549 cell and normal PBMC in a concentration-dependent manner and showed post-effect after pemetrexed was eliminated from the culture medium for 24 hours.2) The supplement of extrinsic folate can weaken the effect of pemetrexed in inhibiting the proliferation capacity and in inducing the apoptosis of A549 cell and normal PBMC.When the concentration of extrinsic folate was increased,the inhibition on the cytotoxicity of pemetrexed in both groups decreased correspondingly.