Abstract
The aim of the present study was to determine the radiosensitization effect of the combination of curcumin and cisplatin on non-small cell lung cancer (NSCLC) A549 cells. Cell viability was analyzed using the MTT assay following treatment with different concentrations of curcumin and cisplatin for 24~72 h. Survival fraction (SF) value of the treatment groups (single irradiation, curcumin + irradiation, cisplatin + irradiation, and curcumin + cisplatin + irradiation) treated with different doses of X-ray radiation were evaluated using colony formation assay, according to a multi-target single-hit model. Migration and invasion as well as the levels of epidermal growth factor receptor (EGFR) protein following 24 h were detected by scratch wound assay, Matrigel assay and western blot analysis, respectively. The results of the present study demonstrated that the viability of the cells decreased after being treated by curcumin, and the inhibitory effect was dose and time-dependent as the concentration of curcumin increased from 10 to 200 µmol/l (P<0.05). SF value was lower in the curcumin + cisplatin + irradiation group compared with the other three treatment groups at 2~10 Gy. Furthermore, SF value was lower in the curcumin + irradiation group at 4~10 Gy. The SF value was also lower in the cisplatin + irradiation group at 2~10 Gy compared with the single irradiation group (P<0.05). The sensitization enhancement ratios in the curcumin + irradiation, cisplatin + irradiation, and curcumin + cisplatin + irradiation groups were 1.24, 1.31 and 1.96, respectively. The migration distance, the number of cells invaded through the transmembrane, and the level of EGFR protein in four treatment groups were the highest in the single irradiation group, compared with the other three treatment groups (P<0.05). Furthermore, the radiosensitization effects of curcumin and cisplatin on NSCLC A549 cells, which include inhibition of proliferation, migration and invasion, may be associated with the inhibition of the EGFR-associated signaling pathway.