Establishment of Cisplatin-Resistant Human Endometrial Cancer Cell Line and the Study of Its Resistant Mechanisms

Objective To establish the cisplatin(DDP)-resistant cell line from human endometrial cancer cell line Ishikawa and to investigate its resistant mechanism to DDP. Methods A resistant endometrial cancer cell line ISH/DDP was established by gradually increasing dose of cisplatin and high-dose stimulation. The resistant index was estimated by 3-(4,5-dimethylthiazol-zyl)-5-(3-carboxymethoxyphenyl-2-(4-sulfophenyl)-2H-tetrazolium,inner salt (MTS) assay. Cell growth curve, doubling time and cell cycle phase distribution were measured; drug-resistant protein of breast cancer resistance protein (BCRP),P-glycoprotein (P-gp) and glutathione-S-transferase-π (GST-π) were examined by immuocytochemistry. Results The DDP-resistant cell line ISH/DDP was established with the resistant index of 3. 77. The proliferation of ISH/DDP got slow, doubling time prolonged, which were 40. 1 hours, while it was 34. 1 hours in Ishikawa (P<0.05); and the cell number of G0/G1 phase [(44. 3 ±5. 7)% and (39. 0 ± 10. 7)% ,P >0. 05] and G2/M phase [(11.9 ±0.7)% and (5. 7 ±2. 4)% ,P <0. 05] decreased, while S-phase [(44. 2 ±6.1)% and (55. 3 ± 8. 4) % , P < 0. 05] increased compared with parent cells. The comprehensive score of the expression of BCRP in ISH/DDP was 16. 3 ± 2. 0, while it was 13.4 ± 1. 5 in Ishikawa (P < 0. 05). The score of the expression of P-gp in ISH/DDP and Ishikawa were 15. 5 ± 1. 2 and 16. 1 ± 1. 0 (P > 0. 05) ,respectively. The score of the expression of GST-π in ISH/DDP and Ishikawa were 15. 2 ± 1. 9 and 14. 9 ± 1.1 (P > 0. 05) . Conclusion ISH/DDP cell line showed a typical resistant phenotype and biological characteristics, which may be accounted for high BCRP expression.