title: Epidermal growth factor modifies cell cycle control in A431 human squamous carcinoma cells damaged by ionizing radiation.
abstract: Epidermal growth factor (EGF) has been shown to radiosensitize A431 and other human squamous carcinoma cells with high numbers of surface EGF receptors. In this study of the mechanistic basis of EGF-induced radiosensitization, both EGF and ionizing radiation caused G1 phase arrests in cycling A431 cells, but only radiation caused a G2-M arrest. However, EGF enhanced the magnitude of this G2-M arrest, suggesting an interaction of signaling pathways involved in cellular responses to EGF and radiation damage. EGF and radiation also uniquely perturbed cyclin A and B1 mRNA levels during the time of maximum radiation-induced G2-M arrest. The effects of EGF on G2-M events probably originated in cells in G1. It is possible that aberrant EGF signal transduction in human squamous carcinoma cells may be exploited as a novel strategy for radiotherapy.
authors.affiliation: Life Sciences Division, SRI International, Menlo Park, California 94025.
authors.forename: K R
authors.initials: KR
authors.lastname: Laderoute
authors.forename: W A
authors.initials: WA
authors.lastname: Ausserer
authors.forename: A M
authors.initials: AM
authors.lastname: Knapp
authors.forename: T D
authors.initials: TD
authors.lastname: Grant
authors.forename: R M
authors.initials: RM
authors.lastname: Sutherland
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000473:pathology* / Q000532:radiotherapy*; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D016213:Cyclins / Q000235:genetics; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D066246:ErbB Receptors / Q000187:drug effects / Q000528:radiation effects; D016195:G2 Phase / Q000187:drug effects / Q000528:radiation effects; D006801:Humans; D008938:Mitosis / Q000187:drug effects / Q000528:radiation effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D011839:Radiation, Ionizing; D013268:Stimulation, Chemical; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000528:radiation effects
chemical_list: D016213:Cyclins; D012333:RNA, Messenger; D004815:Epidermal Growth Factor; D066246:ErbB Receptors