ER status in adriamycin-sensitive and adriamycin-resistant MCF-7 human breast cancer cell lines

Objective To study the ER status in Adriamycin-sensitive and Adriamycin-resistant MCF-7 human breast cancer cell lines. MethodsThe status of ER of MCF-7/ADR and parental MCF-7 cells was detected by Western blot. The expression of ER mRNA was detected by RT-PCR .The growth and the sensitivity to Estrogen(E 2) and droloxifene(Dro) of cells were investigated by MTT assay, and the distribution of cell cycle was detected by flow cytometric assay. Results ER and ER mRNA were positive in MCF-7 cells, and negative in MCF-7/ADR cells. In comparison with MCF-7 cells, MCF-7/ADR cells showed lower growth rate, and the cell cycle was arrested at G 0/G 1 phase. E 2 at concentrations between 1×10 -12mol/L to 1×10 -7mol/L significantly stimulated the growth of MCF-7, but did not stimulate the growth of MCF-7/ADR.Dro at concentrations between 10*!μmol/L to 20*!μmol/L significantly inhabited the growth of MCF-7, and the inhibition was dose-dependent. Dro at concentrations below 20*!μmol/L did not inhibit the growth of MCF-7/ADR, dro inhabited the growth of MCF-7/ADR only at the concentration of 20*!μmol/L, and the inhibition was more effective than MCF-7. Conclusions ER was lost in MCF-7/ADR cells,probably at mRNA level. Compared with MCF-7, the growth rate of MCF-7/ADR decreased,MCF-7/ADR cells lost the dependence on estrogen and the sensitivity to endocrine therapy.