Hesperetin induces apoptosis in gefitinib-resistant NCI-H1975 cells through ROS mediated endoplasmic reticulum stress
AIM:To investigate the inhibitory ef-fect and mechanism of hesperetin(HST)on human gefitinib-resistant NCI-H1975 lung adenocarcinoma cells.METHODS:CCK-8 assay was used to detect the effects of HST on the proliferation of NCI-H1975 cells;Annexin V-FITC/PI double staining was used to detect HST-induced apoptosis of NCI-H1975 cells;flow cytometry was used to observe the effects of HST and HST+acetylcysteine(NAC)combined on the levels of reactive oxygen species(ROS)in NCI-H1975 cells;Western blot was used to detect the expression of Bcl-2,Bax,Cleaved Cas-pase-3,p-eIF2α,eIF2α and CHOP proteins in NCI-H1975 cells by HST,NAC+HST and Salubrinal+HST.The antitumor effect of HST in vivo was stud-ied by constructing a xenograft model in nude mice;HE staining was used to observe the effect of HST on the histopathological morphology of heart,liver,kidney and xenograft in tumor-bearing mice;immunohistochemistry was used to detect the ef-fect of HST on p-eIF2α protein in xenograft tissues.RESULTS:Compared with the control group,HST at 37.5 μmol/L for 24 h significantly inhibited the via-bility of NCI-H1975 cells(P<0.05),and NAC attenu-ated the inhibitory effect of HST;concentrations greater than 150 μmol/L increased intracellular ROS levels(P<0.05),induced apoptosis(P<0.05),and increased Caspase3 activity(P<0.01),and com-pared with HST 300 μmol/L group,ROS levels,apoptosis rate,and Caspase3 activity were signifi-cantly decreased in NAC+HST 300 μmol/L group(P<0.01);HST up-regulated Bax,Cleaved Caspase-3,CHOP,and p-elF2α expression and down-regulated Bcl-2 expression in a concentration-dependent manner(P<0.01),and compared with HST 300μmol/L group,Bax and Cleaved Caspase-3 expres-sion was decreased and Bcl-2 expression was in-creased in Sal+HST 300 μmol/L group;p-eIF2αand CHOP expression were significantly down-regu-lated in the NAC+HST 300 μmol/L and Sal+HST 300 μmol/L groups(P<0.01).In vivo,experiments showed that HST could significantly inhibit the growth of transplanted tumors and up-regulate p-eIF2α protein expression(P<0.05),and had no sig-nificant adverse effects on the growth status,body weight and important organs(heart,liver and kid-ney)of nude mice.CONCLUSION:HST inhibits the proliferation of gefitinib-resistant NCI-H1975 lung adenocarcinoma cells in vitro and in vivo,and the mechanism may be related to HST mediating ER stress-induced apoptosis of NCI-H1975 cells through ROS.