title: Extra-nuclear signaling of progesterone receptor to breast cancer cell movement and invasion through the actin cytoskeleton.
abstract: Progesterone plays a role in breast cancer development and progression but the effects on breast cancer cell movement or invasion have not been fully explored. In this study, we investigate the actions of natural progesterone and of the synthetic progestin medroxyprogesterone acetate (MPA) on actin cytoskeleton remodeling and on breast cancer cell movement and invasion. In particular, we characterize the nongenomic signaling cascades implicated in these actions. T47-D breast cancer cells display enhanced horizontal migration and invasion of three-dimensional matrices in the presence of both progestins. Exposure to the hormones triggers a rapid remodeling of the actin cytoskeleton and the formation of membrane ruffles required for cell movement, which are dependent on the rapid phosphorylation of the actin-regulatory protein moesin. The extra-cellular small GTPase RhoA/Rho-associated kinase (ROCK-2) cascade plays central role in progesterone- and MPA-induced moesin activation, cell migration and invasion. In the presence of progesterone, progesterone receptor A (PRA) interacts with the G protein G alpha(13), while MPA drives PR to interact with tyrosine kinase c-Src and to activate phosphatidylinositol-3 kinase, leading to the activation of RhoA/ROCK-2. In conclusion, our findings manifest that progesterone and MPA promote breast cancer cell movement via rapid actin cytoskeleton remodeling, which are mediated by moesin activation. These events are triggered by RhoA/ROCK-2 cascade through partially differing pathways by the two compounds. These results provide original mechanistic explanations for the effects of progestins on breast cancer progression and highlight potential targets to treat endocrine-sensitive breast cancers.
authors.affiliation: Molecular and Cellular Gynecological Endocrinology Laboratory, Department of Reproductive Medicine and Child Development, University of Pisa, Pisa, Italy.
authors.forename: Xiao-Dong
authors.initials: XD
authors.lastname: Fu
authors.forename: Maria S
authors.initials: MS
authors.lastname: Giretti
authors.forename: Chiara
authors.initials: C
authors.lastname: Baldacci
authors.forename: Silvia
authors.initials: S
authors.lastname: Garibaldi
authors.forename: Marina
authors.initials: M
authors.lastname: Flamini
authors.forename: Angel Matias
authors.initials: AM
authors.lastname: Sanchez
authors.forename: Angiolo
authors.initials: A
authors.lastname: Gadducci
authors.forename: Andrea R
authors.initials: AR
authors.lastname: Genazzani
authors.forename: Tommaso
authors.initials: T
authors.lastname: Simoncini
mesh_terms: D000199:Actins / Q000378:metabolism*; D001943:Breast Neoplasms / Q000378:metabolism*; D045744:Cell Line, Tumor; D002465:Cell Movement; D003599:Cytoskeleton / Q000378:metabolism*; D018450:Disease Progression; D006801:Humans; D017258:Medroxyprogesterone Acetate / Q000494:pharmacology; D008840:Microfilament Proteins / Q000378:metabolism; D009361:Neoplasm Invasiveness; D011374:Progesterone / Q000494:pharmacology; D011980:Receptors, Progesterone / Q000378:metabolism*; D015398:Signal Transduction; D054460:rho-Associated Kinases / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
chemical_list: D000199:Actins; D008840:Microfilament Proteins; D011980:Receptors, Progesterone; C066737:RHOA protein, human; C071058:moesin; D011374:Progesterone; D017258:Medroxyprogesterone Acetate; C515852:ROCK2 protein, human; D054460:rho-Associated Kinases; D020742:rhoA GTP-Binding Protein