The effects of cetuximab in combination with docetaxel for the acquired resistance to EGFR-TKI in non-small cell lung cancer cells

Objective: To investigate the effects of cetuximab in combination with docetaxel on the acquired resistance to epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) in non-small cell lung cancer PC9/G2 cells in vitro and in vivo. Methods: The PC9/G2 cells were treated with different concentrations of cetuximab and docetaxel alone and in combination, and then the proliferation of PC9/G2 cells was detected by MTT assay and the half inhibitory concentration (IC50) values were calculated. After the PC9/G2 cells treatment with 40 μg/mL cetuximab and 25 μmol/L docetaxel alone and in combination, the apoptosis of PC9/G2 cells was measured by flow cytometry, then the expression levels of EGFR and EGFR pTyr1173, pTyr1086 and pTyr845 proteins were determined by Western blotting. The tumor xenograft of PC9/G2 cells in nude mice was established. Intraperitoneal injection of cetuximab (10 mg/kg) and docetaxel (40 mg/kg) alone and in combination was performed, and the growth of tumor xenograft was observed. Results: The IC50 value of cetuximab in combination with docetaxel in PC9/G2 cells was lower than those of cetuximab and docetaxel alone (P 0.05). The growth inhibition rate of tumor xenograft of PC9/G2 cells in nude mice treated with cetuximab in combination with docetaxel was higher than those treated with cetuximab and docetaxel alone (P < 0.01). Conclusion: Cetuximab in combination with docetaxel can inhibit the proliferation of PC9/G2 cells in vitro and in vivo. DOI:10.3781/j.issn.1000-7431.2014.07.002