Reversal of the resistance to adriamycin in human breast cancer cell line MCF-7/ADM by TMP

Objective To study the reversal or the resistance to adriamycin in human breast cancer cell line MCF-7/ADM by TMP.Methods The drug sensitivity of MCF-7/ADM cells was measured by MTT assay. The intracellular concentration of ADM was determined by fluorescent-spectrophotometry.The cell apoptosis percentage of MCF-7/ADM was demonstrated by flow cytometry.Results The IC_(50) value of TMP in MCF-7/ADM cell line was significantly decreased by the non-cytotoxic dose(320 mg/L) or low-cytotoxic dose(1250 mg/L) of TMP(P(0.01)) and the resistance-reversing effect was 2.13-folds, 2.82-folds respectively compared with the IC_(50) value of ADM in MCF-7/ADM cells.The intracellular ADM concentration in MCF-7/ADM cells were significantly elevated by TMP at the same dose(P0.0l).The cell apoptosis percentage in MCF-7/ADM cells was significantly increased by TMP(P0.0l).Conclusion TMP could partially reverse the resistance to ADM in human breast cancer MCF-(7/ADM) cell line,which may be related to the increased intracellular ADM concentration.