The anti-progestin RU-486 inhibits viability of MCF-7 breast cancer cells by suppressing WNT1

The Wnt signaling pathway is activated in over 50% of women with breast cancer and contributes to tumor progression. Here, we investigated the effects of RU-486 on Wnt signaling in breast cancer cell lines. RU-486 reduced viability of the progesterone receptor-positive MCF-7 and T-47D cells, but had no effect on the triple-negative MDA-MB-231 cells. Furthermore, RU-486 suppressed WNT1 expression of MCF-7 cells by 99%. The addition of recombinant WNT1 partially reversed the RU-486-dependent inhibition of viability in MCF-7, but not in T-47D cells. In conclusion, we identified WNT1 as a novel mediator of the anti-tumor effects of RU-486 in MCF-7 cells.

► RU-486 suppresses WNT1 in MCF-7 cells.
► RU-486 decreases cell viability of PR positve breast cancer cell lines.
► Exogenous WNT1 partially prevents effects on cell proliferation, but not on apoptosis in breast cancer cells.
► WNT1 may a mediator of the anti-tumor effects of RU-486 in breast cancer.