Induced IGF-1R activation contributes to gefitinib resistance following combined treatment with paclitaxel, cisplatin and gefitinib in A549 lung cancer cells

Gefitinib demonstrates excellent performance in the treatment of lung adenocarcinoma patients; yet, there was no added benefit in combination with chemotherapy as reported in a phase III clinical trial. For exploring the mechanism of the failed combination therapy in lung cancer, in the present study, four therapy assessment groups, including a control group, a chemotherapy group [paclitaxel + cisplatin (TP)], a gefitinib monotherapy group (G) and a combination group [paclitaxel + cisplatin + gefitinib (TP+G)], were established in an A549 cell line and mouse xenotransplanted tumor models. By HPLC, we found that the gefitinib concentration was significantly higher in the combination group when compared to that in the G group in the non-small cell lung cancer cell line, A549 (p