MECHANICAL AUGMENTATION OF PROGESTERONE ACTION IN UTERINE FIBROID CELLS REQUIRES PROGESTERONE RECEPTOR B (PRB) AND IS ASSOCIATED WITH PRB PHOSPHORYLATION

Abstract

Progesterone responsive genes are implicated in fibroid growth, but the mechanisms that integrate mechanical signaling with progesterone receptor activation are not fully understood. We previously reported that a mechanically stiff substrate promoted progesterone-dependent, progesterone receptor-mediated gene activation in fibroid cells. Here we investigated whether altered mechanical stiffnesses directly influenced phosphorylation of progesterone receptor B (PRB), and used siRNA directed against PRB to test whether this isoform was required to transduce mechanical signals in fibroid cells.