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.