Inhibition of prohibitin 2 enhances the sensitivity of non-small cell lung cancer cell line A549 to erlotinib / 基础医学与临床

ABSTRACT

Objective To explore the effects of prohibitin 2(PHB2)on sensitivity of non-small cell lung cancer cell line A549 to erlotinib(Erl)and its potential mechanisms.Methods RACK1-specific small interfering RNA was transfected in A549 cells for knocking-down of PHB2.The effects of PHB2 inhibition on cell proliferation and apop-tosis induced by Erl were observed.The colocalization of microtuble-associated protein light chain 3 alpha(LC3)and mitochondria was visualized by MitoTracker staining and green fluorescent protein-microtuble-associated protein light chain 3 alpha(GFP-LC3)transfection.Cell proliferation was detected by 5-ethynyl-2′-deoxyuridine(EdU)staining.Cell colony formation was evaluated by colony forming assay.Apoptotic index of A549 cells was evaluated by TUNEL.Western blot was used to measure the expressions of PHB2 and LC3Ⅱ.Mitochondrial transmembrane potential,cytochrome c and respiratory chain complexⅠ/Ⅱ/Ⅴactivity were analyzed by the commercially availa-ble kits.Results Compared with the siPHB2 and siCtrl+Erl group,the EdU-positive A549 cells and the number of cell colonies decreased significantly(P＜0.05),while the TUNEL-positive A549 cells increased significantly(P＜0.05)in the siPHB2+Erl group.In addition,compared with the siPHB2 and siCtrl+Erl group,mitochondrial transmembrane potential and respiratory chain complexⅠ/Ⅱ/Ⅴactivity decreased significantly(all P＜0.05)and the levels of cytochrome c increased in mitochondrial fractions(P＜0.05)and decreased in cytosolic fractions(P＜0.05)in the siPHB2+Erl group.Conclusions PHB2 inhibition significantly improves sensitivity of A549 cells to Erl,which may be explained by inhibition of PHB2-mediated mitochondrial autophagy.