Role of the short isoform of the progesterone receptor in breast cancer cell invasiveness at estrogen and progesterone levels in the pre- and post-menopausal ranges.

ABSTRACT: Overexpression of the progesterone receptor (PR) isoform A (PR-A) is a negative prognosticator for estrogen receptor (ER)-positive breast cancer but in vitro studies have implicated PR-B in progestin-induced invasiveness. As estrogen is known to suppress invasiveness and tumor progression and as the in vitro studies were conducted in models that either lacked ER or excluded estrogen, we examined the role of PR isoforms in the context of estrogen signaling. Estrogen (< 0.01nM) strongly suppressed invasiveness in various ER+ model cell lines. At low (< 1nM) concentrations, progestins completely abrogated inhibition of invasiveness by estrogen. It was only in a higher (5 nM - 50 nM) concentration range that progestins induced invasiveness in the absence of estrogen. The ability of low dose pr

SUBMITTER: McFall T 

PROVIDER: S-EPMC4741755 | biostudies-literature | 2015 Oct

REPOSITORIES: biostudies-literature