In vitro estradiol-sensitivity characterization of the MCF-7, ZR-75, MDA-MB-231 and T47-D human breast neoplastic cell lines.

Even if it seems that everything has been said about the influence of estradiol on cell proliferation in human breast cancer cell lines such as MCF-7, T47-D, ZR-75 and MDA-MB-231, in this study of the possible autocrine and/or paracrine role of 17 beta estradiol (E2) on the proliferation of human breast cancer cell lines we nevertheless offer some complementary information in this field of research. We exogenously stimulated the cell lines by the addition to the culture media of E2 and the anti-E2 antibody. The latter neutralizes the effects of any endogenous E2. The cell proliferation was assessed by means of the MTT colorimetric test. We thus showed that the level of sensitivity of various breast cancer cell lines to estradiol in terms of cell proliferation depends on the experimental schedule chosen. Indeed, the addition of E2 to the culture media stimulated the growth of the the ZR-75 and T47-D cell lines conventionally described as estrogen-receptor positive (ER+). For the MCF-7 cell line and the conventionally described as estrogen-receptor negative (ER-) MDA-MB-231 cell line, this is not the case. In sharp contrast, the addition to the culture media of the antibody neutralizing the biophysical activity of E2 sharply decreased the proliferation rate of the four cell lines under study. So these four cell lines in fact seem to be estradiol-sensitive. Thus, those which do not react to the addition of estradiol might use E2 in an autocrine and/or paracrine manner.