20(S)-ginsenoside Rg3 sensitizes human non-small cell lung cancer cells to icotinib through inhibition of autophagy.

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR–TKIs) have become a standard therapy for non-small cell lung cancer (NSCLC) patients with sensitive mutations. However, acquired resistance inevitably emerges after a median of 6–12 months. It has been demonstrated that autophagy plays an important role in EGFR–TKI resistance. 20(S)-ginsenoside Rg3 (Rg3) is proposed to sensitize the cancer cells to chemotherapy by inhibiting autophagy. We examined the ability of Rg3 to inhibit autophagy and increase the sensitivity of NSCLC cells to icotinib. We show that the induction of autophagy in response to icotinib contributes to the development of icotinib resistance. Rg3 is capable of inhibiting autophagic flux and enhancing the sensitivity of NSCLC cells to icotinib. The resistance to icotinib could also be reversed through Rg3-induced autophagy inhibition. Autophagy inhibition by Rg3 increases the therapeutic response in both icotinib-sensitive and icotinib-resistant NSCLC cells with an EGFR-activating mutation and may be an effective new treatment strategy for this disease.