RESUMO
Objective:The purpose of this study was to investigate the expression and role of N-myc downstream regulatory gene 2 (NDRG2) in radiation resistance of bladder cancer cells.Methods:T24 cells were cultured in vitro and irradiated with different doses of X-ray (0, 2, 4, 8, 10 and 20 Gy). The best dose of X-ray was selected for subsequent treatment. The radioresistant BCa cell line T24/R was established. The cytotoxicity of T24/R cells was detected by counting kit-8 (CCK-8) method. The proliferation and invasion ability of T24/R cells and T24 cells were detected by flow cytometry and transwell, respectively. Western blot was used to detect the expression of epithelial mesenchymal transition (EMT) related proteins. The survival rate of T24/R group (control group) and T24/R-NDRG 2 group was detected, and the migration ability of T24/R-NDRG 2 cells was detected after 2 Gy treatment. Results:The cell viability was inhibited significantly when the dose of X-ray was ≥2 Gy X-ray, so 2 Gy X-ray irradiation was chosen as the best condition for BCa cytotoxicity and T24/R radiation resistance cell line was successfully established; Apoptosis test showed that the number of S-phase cells was increased in T24/R group, and the proportion of S-phase cells in T24/R vs T24 was (26.49±4.5)% vs (14±2.6)% ( P<0.05); Transwell test showed that T24/R cells showed stronger migration ability than control group ( P<0.05), but there was no significant difference in EMT related protein expression between the two groups ( P>0.05). Overexpression of NDRG2 can significantly decreased the activity and migration ability of radiation-resistant T24/R cells ( P<0.05) when the radiation dose was gradually increasing in both groups. Conclusions:The radiation resistance of BCa cells is one of the causes of local tumor recurrence. Up-regulation of NDRG2 expression can inhibit the radiation resistance of T24 cells, so it can be used as a candidate for treatment of radiation-resistant BCa patients.