title: Membrane-Tethered Intracellular Domain of Amphiregulin Promotes Keratinocyte Proliferation.
abstract: The epidermal growth factor receptor (EGFR) and its ligands are essential regulators of epithelial biology, which are often amplified in cancer cells. We have previously shown that shRNA-mediated silencing of one of these ligands, amphiregulin (AREG), results in keratinocyte growth arrest that cannot be rescued by soluble extracellular EGFR ligands. To further explore the functional importance of specific AREG domains, we stably transduced keratinocytes expressing tetracycline-inducible AREG-targeted shRNA with lentiviruses expressing silencing-proof, membrane-tethered AREG cytoplasmic and extracellular domains (AREG-CTD and AREG-ECD), as well as full-length AREG precursor (proAREG). Here we show that growth arrest of AREG-silenced keratinocytes occurs in G2/M and is significantly restored by proAREG and AREG-CTD but not by AREG-ECD. Moreover, the AREG-CTD was sufficient to normalize cell cycle distribution profiles and expression of mitosis-related genes. Our findings uncover an important role of the AREG-CTD in regulating cell division, which may be relevant to tumor resistance to EGFR-directed therapies.
authors.affiliation: Department of Dermatology, University of Michigan, Ann Arbor, Michigan, USA. Electronic address: sstoll@umich.edu.
authors.forename: Stefan W
authors.initials: SW
authors.lastname: Stoll
authors.affiliation: Department of Dermatology, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Philip E
authors.initials: PE
authors.lastname: Stuart
authors.affiliation: Department of Dermatology, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Sylviane
authors.initials: S
authors.lastname: Lambert
authors.affiliation: Cell Cycle, Stem Cells and Cancer Lab, Instituto de Investigación Marques de Valdecilla (IDIVAL), Santander, Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: Gandarillas
authors.affiliation: Department of Dermatology, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Laure
authors.initials: L
authors.lastname: Rittié
authors.affiliation: Department of Dermatology, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Johnston
authors.affiliation: Department of Dermatology, University of Michigan, Ann Arbor, Michigan, USA; Ann Arbor Veterans Affairs Health System, Ann Arbor, Michigan, USA.
authors.forename: James T
authors.initials: JT
authors.lastname: Elder
mesh_terms: D066258:Amphiregulin / Q000235:genetics; D000818:Animals; D015153:Blotting, Western; D049109:Cell Proliferation / Q000235:genetics*; D002478:Cells, Cultured; D066255:EGF Family of Proteins / Q000235:genetics*; D004797:Enzyme-Linked Immunosorbent Assay; D066246:ErbB Receptors / Q000378:metabolism; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation; D020868:Gene Silencing; D006801:Humans; D015603:Keratinocytes / Q000166:cytology*; D051379:Mice; D018345:Mice, Knockout; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods; D015398:Signal Transduction / Q000235:genetics
chemical_list: D066258:Amphiregulin; C587849:Areg protein, mouse; D066255:EGF Family of Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D066246:ErbB Receptors