Chemoprevention of UV light-induced skin tumorigenesis by inhibition of the epidermal growth factor receptor.
The epidermal growth factor receptor (EGFR) is activated in skin cells following UV irradiation, the primary cause of nonmelanoma skin cancer. The EGFR inhibitor AG1478 prevented the UV-induced activation of EGFR and of downstream signaling pathways through c-Jun NH2-terminal kinases, extracellular signal-regulated kinases, p38 kinase, and phosphatidylinositol 3-kinase in the skin. The extent to which the UV-induced activation of EGFR influences skin tumorigenesis was determined in genetically initiated v-ras(Ha) transgenic Tg.AC mice, which have enhanced susceptibility to skin carcinogenesis. Topical treatment or i.p. injection of AG1478 before UV exposure blocked the UV-induced activation of EGFR in the skin and decreased skin tumorigenesis in Tg.AC mice. AG1478 treatment before each of several UV exposures decreased the number of papillomas arising and the growth of these tumors by approximately 50% and 80%, respectively. Inhibition of EGFR suppressed proliferation, increased apoptotic cell death, and delayed the onset of epidermal hyperplasia following UV irradiation. Genetic ablation of Egfr similarly delayed epidermal hyperplasia in response to UV exposure. Thus, the UV-induced activation of EGFR promotes skin tumorigenesis by suppressing cell death, augmenting cell proliferation, and accelerating epidermal hyperplasia in response to UV. These results suggest that EGFR may be an appropriate target for the chemoprevention of UV-induced skin cancer.
El-Abaseri
Taghrid B
TB
Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, Nebraska 68178, USA.
Fuhrman
Jill
J
Trempus
Carol
C
Shendrik
Igor
I
Tennant
Raymond W
RW
Hansen
Laura A
LA
D000818:Animals; D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D049109:Cell Proliferation / Q000187:drug effects / Q000528:radiation effects; D004789:Enzyme Activation / Q000528:radiation effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066246:ErbB Receptors / Q000037:antagonists & inhibitors* / Q000172:deficiency / Q000502:physiology; D006965:Hyperplasia; D020935:MAP Kinase Signaling System / Q000528:radiation effects; D051379:Mice; D008819:Mice, Nude; D009381:Neoplasms, Radiation-Induced / Q000201:enzymology / Q000209:etiology / Q000517:prevention & control*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D011799:Quinazolines; D012867:Skin / Q000473:pathology / Q000528:radiation effects; D012878:Skin Neoplasms / Q000201:enzymology / Q000209:etiology / Q000517:prevention & control*; D020032:Tyrphostins / Q000494:pharmacology*; D014466:Ultraviolet Rays / Q000009:adverse effects
D016588:Anticarcinogenic Agents; D004791:Enzyme Inhibitors; D066246:ErbB Receptors; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D011799:Quinazolines; D020032:Tyrphostins; C101044:RTKI cpd