RESUMO
Objective To explore the different mechanisms of to cisplatin (CDDP) resistance in human epithelial ovarian cancer cell lines by two different methods. Methods Two resistant cell lines were established: SKOV3/CDDP-P and SKOV3/CDDP-80. They were induced from epithelial ovarian cancer cell line SKOV3 respectively by pulse and intermittent exposures to cisplatin during the period of 16 months. The biological characteristics of all the cell lines were determined using light microscopy and cell counting. Drug sensitivity was monitored by MTT assay. The cell cycle was examined by flow cytometry. The mRNA expression of MDR1,MRP1,LRP1 and GST-? was determined by RT-PCR. Results The resistance indexes of SKOV3/CDDP-P and SKOV3/CDDP-80 were 4.12?2.01 and 11.50?3.15,respectively. Both the two resistant cell lines had some changes in biological characteristics in which SKOV3/CDDP-80 showed more distinct changes. The expression of MDR1 was up-regulated,and the expression of MRP1 and LRP1 was down-regulated,and the expression of GST-? showed no significant changes inSKOV3/CDDP-P. However,SKOV3/CDDP-80 showed a great increases in MDR1,and there was no significant changes in MRP1,LRP1 and GST-?. Conclusion The results suggest that there are many differences between the two resistant cell lines which involved in multi-gene changes. The intermittent administration has greater trend to develop resistance.