title: Progesterone receptors upregulate Wnt-1 to induce epidermal growth factor receptor transactivation and c-Src-dependent sustained activation of Erk1/2 mitogen-activated protein kinase in breast cancer cells.
abstract: Progesterone receptor (PR) ligand binding induces rapid and transient (5- to 10-min) activation of cytosolic c-Src-Ras-Erk1/2 mitogen-activated protein kinase (MAPK) signaling that is independent of PR functioning as transcription factors. Here, we have explored the integration of PR-dependent transcription and rapid signaling events in breast cancer cells. PR-B, but not PR-A, induced robust and sustained (6- to 72-h) Erk1/2 activation that was required for elevated cyclin D1 protein but not mRNA levels. Sustained Erk1/2 activation in response to progestins occurred via a novel mechanism distinct from rapid signaling initiated by PR/c-Src interactions and required the PR-B DNA-binding domain (DBD). PR/progestin upregulated epidermal growth factor receptor (EGFR) and Wnt-1. In response to PR-induced Wnt-1 signaling, matrix metalloprotease (MMP)-mediated membrane-proximal shedding of EGFR ligands transactivated EGFR and induced persistent downstream c-Src and Erk1/2 activities. T47D cell anchorage-independent growth was stimulated by progestins and blocked by inhibition of Erk1/2, c-Src, EGFR, or RNA interference of Wnt-1. Similarly, cell growth in soft agar required the PR DBD but was sensitive to disruption of PR/c-Src interactions, suggesting that both PR-B-induced rapid signaling events and nuclear actions contribute to this response. Our discovery that progestins are capable of robust autocrine activation of EGFR and sustained Erk1/2 signaling provides further support for the physiological linkage of growth factor and steroid hormone signaling. PR-B-induced sustained MAPK signaling may provide prosurvival or proliferative advantages to early breast cancer lesions.
authors.affiliation: Departments of Medicine and Pharmacology, Division of Hematology, Oncology, and Transplantation, University of Minnesota Cancer Center, 420 Delaware Street SE, MMC 806, Minneapolis, MN 55455, USA.
authors.forename: Emily J
authors.initials: EJ
authors.lastname: Faivre
authors.forename: Carol A
authors.initials: CA
authors.lastname: Lange
mesh_terms: D001943:Breast Neoplasms; D045744:Cell Line, Tumor; D004789:Enzyme Activation; D066246:ErbB Receptors / Q000378:metabolism*; D005260:Female; D006801:Humans; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010766:Phosphorylation; D011372:Progestins / Q000378:metabolism; D011485:Protein Binding; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D017434:Protein Structure, Tertiary; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000502:physiology*; D011980:Receptors, Progesterone / Q000502:physiology*; D015398:Signal Transduction; D015533:Transcriptional Activation; D015854:Up-Regulation; D051155:Wnt1 Protein / Q000378:metabolism*
chemical_list: D011372:Progestins; D047428:Protein Kinase Inhibitors; D011980:Receptors, Progesterone; D051155:Wnt1 Protein; C101118:progesterone receptor A; C097314:progesterone receptor B; D066246:ErbB Receptors; D016392:Proto-Oncogene Proteins pp60(c-src); D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3