Establishment and characteristics of a paclitaxel resistant human mammaryadenocarcinoma cell subline(MCF-7/Taxol)

Aim To establish a new paclitaxel resistant human mammary adenocarcinoma cell subline(MCF-7/Taxol) and investigate its characteristics.Methods A paclitaxel resistant human mammary adenocarcinoma cell subline(MCF-7/Taxol) was developed by gradually increasing the concentration of Taxol from the parent cell line MCF-7 in vitro.The multidrug resistance of MCF-7/Taxol to anticancer agents was evaluated by SRB assay;the distribution of their cell cycles was detected by flow cytometry;the positive expression rate of P-gP、LRP、ToPoII、GSTπ、ER and PR was measured by S-P immunohistochemistry;the intracellular accumulation of Taxol was assessed by HPLC;the morphological features and the celluar ultrastructure characteristics were observed respectively by light microscopy and scanning electron microscopy.Results MCF-7/Taxol was resistant to several chemotherapy agents,such as Hydroxycamptothecine,Epirubicin,Doxorubicin,Mitoxantone and so on.The IC50 of MCF-7/Taxol to Taxol was 525 times higher than that of MCF-7,and the IC50 of MCF-7/Taxol stopped administrating Taxol for three months was 150 times higher than that of MCF-7.The multiplication time of MCF-7/Taxol was longer than that of the natural cell and the proportion of cells in S-phase increased while that in G1-phase decreased.The expression levels of P-gp、LRP and GSTπ increased,and ER and PR were not observed.The morphology of MCF-7/Taxol became larger and irregular,and the surface of natural cell was in the shape of floss,but MCF-7/Taxol was in the shape of bead.The intracellular of Taxol was observed in both MCF-7/Taxol and stoppage administrating.Conclusions MCF-7/Taxol cell subline was a typical multidrug resistant cell line which had basic characteristics of drug resistance cells.It was supposed that there was a cell subline which was tumor stem cell of MCF-7 included in this multidrug resistant cell line.