Objective      To study the anti-tumor effect of separated or combined application of Pan-HER irreversible inhibitor afatinib and phosphoinositide 3-kinase α (PI3Kα) inhibitor PF-04691502 on epidermal growth factor receptor (EGFR) inhibitor-resistant non-small cell lung cancer (NSCLC) H1975 cells in vitro.        Methods      Effects of afatinib and PF-04691502 (PF) separated or combined application on the proliferation and migration of H

1975 cells were analyzed by cell cycle and apoptosis  with MTS assay

wound-healing assay

and flow cytometry.       Results      Afatinib and PF alone significantly inhibited the proliferation of H1975 cells in a dose-dependent manner. Afatinib combined with PF showed an evident synergetic inhibitory effect. Afatinib and PF separated or combined application both induced cell cycle arrest at G

1

phase (

P

0.05). As compared to the control group

afatinib and PF alone promoted cell apoptosis

and their combination induced a higher apoptotic rate of H1975 cells (

P

0.05).       Conclusion      Pan-HER irreversible inhibitor afatinib and PI3Kα inhibitor PF alone shows significant antitumor effects on drug-resistant NSCLC H1975 cells. Moreover

their combination exhibits synergistic anti-tumor effects.