title: Suppression of epidermal growth factor receptor, mitogen-activated protein kinase, and Pak1 pathways and invasiveness of human cutaneous squamous cancer cells by the tyrosine kinase inhibitor ZD1839 (Iressa).
abstract: Abnormalities in the expression and signaling pathways downstream of the epidermal growth factor receptor (EGFR) contribute to malignant transformation in human cancers, including those of the cutaneous epithelium. Accordingly, novel agents such as the EGFR tyrosine kinase inhibitor ZD1839 (Iressa), are promising, biologically based treatments that are currently in preclinical and clinical development. The process of tumor progression requires, among other steps, increased transformation, directional migration, and enhanced cell survival. This study explored the effect of ZD1839 on the stimulation of p42/44 mitogen-activated protein kinase (MAPK) and p21-activated kinase 1 (Pak1), which are vital for transformation, directional motility, and cell survival, using immortalized keratinocytes (HaCaT cells) and cutaneous squamous cell carcinoma cells. The EGFR and a number of effector kinases (mitogen-activated protein extracellular signal-regulated kinase kinase 1 and 2, MAPK, Pak1, p38, c-JunNH(2)-terminal kinase and extracellular signal-regulated kinase 1) and cell survival proteins (AKT, FKHR, and c-Src) showed constitutive pathway activation in HaCaT and cutaneous squamous cell carcinoma cells. ZD1839 effectively inhibited EGFR and MAPK activation and Pak1 activity in exponentially growing cancer cells. ZD1839 also suppressed EGF-induced stimulation of EGFR autophosphorylation on Y1086 and Y1068, MAPK phosphorylation on T402 and Y404, and Pak1 activity in a dose-dependent manner. In addition, ZD1839 blocked EGF-induced cytoskeleton remodeling, cell growth, and in vitro invasiveness of cancer cells and induced a differentiated squamous cell phenotype. These studies suggest that the EGFR-tyrosine kinase inhibitor ZD1839 may cause potent inhibition of the EGFR, MAPK, and Pak1 pathways, resulting in attenuation of transformed cell phenotypes and induced differentiation in human cancer cells deregulated in these growth factor receptor pathways.
authors.affiliation: Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Barnes
authors.forename: Rozita
authors.initials: R
authors.lastname: Bagheri-Yarmand
authors.forename: Mahitosh
authors.initials: M
authors.lastname: Mandal
authors.forename: Zhibo
authors.initials: Z
authors.lastname: Yang
authors.forename: Gary L
authors.initials: GL
authors.lastname: Clayman
authors.forename: Waun Ki
authors.initials: WK
authors.lastname: Hong
authors.forename: Rakesh
authors.initials: R
authors.lastname: Kumar
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D015153:Blotting, Western; D002294:Carcinoma, Squamous Cell / Q000473:pathology* / Q000628:therapy; D002454:Cell Differentiation; D002455:Cell Division; D045744:Cell Line, Tumor; D002465:Cell Movement; D002470:Cell Survival; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D066246:ErbB Receptors / Q000037:antagonists & inhibitors*; D000077156:Gefitinib; D006801:Humans; D015603:Keratinocytes / Q000166:cytology; D020935:MAP Kinase Signaling System; D008856:Microscopy, Fluorescence; D009361:Neoplasm Invasiveness; D010641:Phenotype; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors*; D011799:Quinazolines / Q000494:pharmacology*; D015398:Signal Transduction; D012878:Skin Neoplasms / Q000473:pathology* / Q000628:therapy; D054462:p21-Activated Kinases
chemical_list: D000970:Antineoplastic Agents; D004791:Enzyme Inhibitors; D011799:Quinazolines; D066246:ErbB Receptors; D011505:Protein-Tyrosine Kinases; C515903:PAK1 protein, human; D017346:Protein Serine-Threonine Kinases; D054462:p21-Activated Kinases; D000077156:Gefitinib