title: Prolactin-induced expression of vascular endothelial growth factor via Egr-1.
abstract: Angiogenesis is a dynamic process regulated by both local and systemic factors. Among these is vascular endothelial growth factor (VEGF), a potent effector of angiogenesis and vascular permeability. Previously we showed that VEGF is temporally and spatially regulated in the mouse mammary gland during development and lactation. Given the functions of prolactin (PRL) during these stages and the supporting role of the vasculature, we investigated the regulation of VEGF by PRL. Treatment of HC11 mouse mammary epithelial and Nb2 rat lymphoma cells with PRL induced VEGF expression. Deletion and mutation analysis identified a GC-rich region in the proximal region of the VEGF promoter that constitutively bound Sp1 and PRL-induced Egr-1. These sites conferred PRL-responsiveness leading to increased VEGF transcription. The induction of VEGF by PRL was PRL receptor-, Jak2- and MAP kinase kinase-dependent. Our results indicate that PRL induces VEGF expression through Egr-1, and implicates VEGF as an intermediary of PRL-regulated angiogenesis.
authors.affiliation: Mammary Biology and Tumorigenesis Laboratory, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-1402, USA.
authors.forename: Anita S
authors.initials: AS
authors.lastname: Goldhar
authors.forename: Barbara K
authors.initials: BK
authors.lastname: Vonderhaar
authors.forename: Josephine F
authors.initials: JF
authors.lastname: Trott
authors.forename: Russell C
authors.initials: RC
authors.lastname: Hovey
mesh_terms: D000818:Animals; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000502:physiology*; D051766:Early Growth Response Protein 1; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D017874:Immediate-Early Proteins / Q000502:physiology*; D053614:Janus Kinase 2; D008321:Mammary Glands, Animal / Q000166:cytology; D051379:Mice; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D018919:Neovascularization, Physiologic; D011388:Prolactin / Q000494:pharmacology*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051381:Rats; D011981:Receptors, Prolactin / Q000378:metabolism; D014157:Transcription Factors / Q000502:physiology*; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics*
chemical_list: D004268:DNA-Binding Proteins; D051766:Early Growth Response Protein 1; C486109:Egr1 protein, mouse; D017874:Immediate-Early Proteins; D011518:Proto-Oncogene Proteins; D011981:Receptors, Prolactin; D014157:Transcription Factors; D042461:Vascular Endothelial Growth Factor A; D011388:Prolactin; D011505:Protein-Tyrosine Kinases; C507924:JAK2 protein, human; C507926:Jak2 protein, mouse; C507927:Jak2 protein, rat; D053614:Janus Kinase 2; D020929:Mitogen-Activated Protein Kinase Kinases