Combination with cooling-heat Chinese medicine Qing-kai-ling, not warming-yang Shen-fu, enhances the antitumor effect of gefitinib in resistant non-small cell lung cancer models in vitro and in vivo

Background: Traditional Chinese Medicine (TCM) prescriptions should be decided according to the TCM treatment principle, and the warming-yang or cooling-heat should be the guide of treatment principle outline. Methods: In order to identify which treatment principle, warming-yang or cooling-heat should be combined with epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) in non-small cell lung cancer (NSCLC), we combined the typical warming-yang drug, Shen-fu (SF), and the typical cooling-heat drug, Qing-kai-ling (QKL) with gefitinib in resistant NSCLC models. Results: The results demonstrated that QKL combined with gefitinib induced significantly increased cell viability inhibition and apoptosis in A549 cell line and significantly smaller tumor volume and lower tumor weight in H1975 xenograft transplanted nude mice. On the contrary, SF combined with gefitinib had significant antagonism effect on both cell viability inhibition and apoptosis in vitro , and on tumor weight in vivo . EGFR phosphorylation inhibition and the downstream PI3K/AKT and RAS/RAF/ERK pathway inhibition served an important role in the synergism effect between QKL and gefitinib in H1975 xenograft transplanted nude mice. Conclusions: The present study indicated that cooling-heat TCM treatment principle may reverse or delay NSCLC resistance to EGFR-TKIs, and combination of them warrants further study.