title: Autocrine regulation of human urothelial cell proliferation and migration during regenerative responses in vitro.
abstract: Regeneration of the urothelium is rapid and effective in order to maintain a barrier to urine following tissue injury. Whereas normal human urothelial (NHU) cells are mitotically quiescent and G0 arrested in situ, they rapidly enter the cell cycle upon seeding in primary culture and show reversible growth arrest at confluency. We have used this as a model to investigate the role of EGF receptor signaling in urothelial regeneration and wound-healing. Transcripts for HER-1, HER-2, and HER-3 were expressed by quiescent human urothelium in situ. Expression of HER-1 was upregulated in proliferating cultures, whereas HER-2 and HER-3 were more associated with a growth-arrested phenotype. NHU cells could be propagated in the absence of exogenous EGF, but autocrine signaling through HER-1 via the MAPK and PI3-kinase pathways was essential for proliferation and migration during urothelial wound repair. HB-EGF was expressed by urothelium in situ and HB-EGF, epiregulin, TGF-alpha, and amphiregulin were expressed by proliferating NHU cells. Urothelial wound repair in vitro was attenuated by neutralizing antibodies against HER-1 ligands, particularly amphiregulin. By contrast, the same ligands applied exogenously promoted migration, but inhibited proliferation, implying that HER-1 ligands provoke differential effects in NHU cells depending upon whether they are presented as soluble or juxtacrine ligands. We conclude that proliferation and migration during wound healing in NHU cells are mediated through an EGFR autocrine signalling loop and our results implicate amphiregulin as a key mediator.
authors.affiliation: Jack Birch Unit for Molecular Carcinogenesis, Department of Biology, University of York, Heslington, York YO10 5YW, UK.
authors.forename: Claire
authors.initials: C
authors.lastname: Varley
authors.forename: Gemma
authors.initials: G
authors.lastname: Hill
authors.forename: Stephanie
authors.initials: S
authors.lastname: Pellegrin
authors.forename: Nicola J
authors.initials: NJ
authors.lastname: Shaw
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Selby
authors.forename: Ludwik K
authors.initials: LK
authors.lastname: Trejdosiewicz
authors.forename: Jennifer
authors.initials: J
authors.lastname: Southgate
mesh_terms: D066258:Amphiregulin; D000906:Antibodies / Q000494:pharmacology; D019898:Autocrine Communication / Q000502:physiology*; D002453:Cell Cycle / Q000235:genetics; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D066255:EGF Family of Proteins; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000235:genetics / Q000276:immunology / Q000494:pharmacology; D066260:Epiregulin; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology; D015870:Gene Expression / Q000235:genetics; D006023:Glycoproteins / Q000235:genetics / Q000276:immunology / Q000494:pharmacology; D006133:Growth Substances / Q000172:deficiency; D066257:Heparin-binding EGF-like Growth Factor; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000276:immunology / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000502:physiology; D011799:Quinazolines / Q000494:pharmacology; D012038:Regeneration / Q000187:drug effects; D016211:Transforming Growth Factor alpha / Q000235:genetics / Q000276:immunology / Q000494:pharmacology; D019459:Urothelium / Q000166:cytology* / Q000502:physiology; D014945:Wound Healing / Q000187:drug effects / Q000502:physiology
chemical_list: C587848:AREG protein, human; D066258:Amphiregulin; D000906:Antibodies; D066255:EGF Family of Proteins; C587880:EREG protein, human; D004791:Enzyme Inhibitors; D066260:Epiregulin; D006023:Glycoproteins; D006133:Growth Substances; C587883:HBEGF protein, human; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; D011799:Quinazolines; D016211:Transforming Growth Factor alpha; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; C088860:4-((3-bromophenyl)amino)-6,7-dimethoxyquinazoline