Estrone and 17β-estradiol reverse breast cancer resistance protein-mediated multidrug resistance

Abstract

Breast cancer resistance protein (BCRP), an adenosine triphosphate-binding cassette transporter, confers resistance to a series of anticancer reagents, including mitoxantrone, SN-38 and topotecan. In the present study, we found that estrone and 17β-estradiol potentiated the cytotoxicity of mitoxantrone, SN-38 and topotecan in BCRP-transduced K562 cells (K562/BCRP). These estrogens showed only a marginal effect, or none, in parental K562 cells. Estrone and 17β-estradiol increased the cellular accumulation of topotecan in K562/BCRP cells, but not in K562 cells, suggesting that these estrogens inhibit the BCRP-mediated drug efflux and overcome drug resistance.