[Evodiamine enhances the radiosensitivity of esophageal squamous cell cancer Eca-109 cells].

Objective To investigate the effect of evodiamine on the radiosensitivity of esophageal squamous cell cancer Eca-109 cells. Methods Eca-109 cells were treated with various concentrations of evodiamine [(10, 20, 40, 60, 80, 100, 120) μg/mL], and then cell proliferation was examined by MTT assay. After the optimal evodiamine concentration was determined, the cells were divided into radiation group (0, 2, 4, 6, 8 Gy X-ray radiation) and radiation combined with evodiamine group (80 μg/mL evodiamine and 0, 2, 4, 6, 8 Gy X-ray radiation) .The radiosensitivity of Eca-109 cells was detected using colony formation assay. Flow cytometry was used to determine cell cycle of Eca-109 cells. The protein expressions of Ku70, Ku80, DNA-PKcs and Rad51 were examined by Western blotting. Results MTT assay showed that evodiamine decreased the proliferation of Eca-109 cells in a concentration-dependent manner. The inhibition reached the maximal level at 80 μg/mL. Compared with radiotherapy alone, the combination of 80 μg/mL evodiamine and radiotherapy improved survival curve and decreased the values of D0 and Dq. Sensitizer enhancement ratio was 1.86±0.06. Furthermore, cell cycle analysis revealed that evodiamine suppressed radiotherapy-induced the G2/M arrest. Additionally, evodiamine treatment also significantly inhibited radiotherapy-induced increase in Ku70, Ku80, DNA-PKcs and Rad51 expressions. Conclusion Evodiamine enhances radiosensitivity of Eca-109 cells during radiotherapy. The effect may be associated with the inhibition of G2/M arrest and the attenuation of Ku70, Ku80, DNA-PKcs and Rad51 expressions.