title: Combined inhibition of MET and EGFR suppresses proliferation of malignant mesothelioma cells.
abstract: Malignant pleural mesothelioma (MPM) is an aggressive neoplasm associated with asbestos exposure. Although expression and activation of receptor tyrosine kinases (RTKs), including MET, have been reported in most MPM, specific RTK inhibitors showed less than the expected response in MPM cells. To determine whether the lack of response of MET inhibitors was due to cooperation with other RTKs, we determined activation status of MET and other RTKs, including epidermal growth factor receptor (EGFR) family of 20 MPM cell lines, and tested whether dual RTK inhibition is an effective therapeutic strategy. We detected MET upregulation and phosphorylation (thus indicating activation) in 14 (70%) and 13 (65%) cell lines, but treatment with MET-specific inhibitors showed weak or modest effect of suppression in most of the cell lines. Phospho-RTK array analysis revealed that MET was simultaneously activated with other RTKs, including EGFR, ErbB2, ErbB3 and platelet-derived growth factor receptor-beta. Combination of MET and EGFR inhibitors triggered stronger inhibition on cell proliferation and invasion of MPM cells than that of each in vitro. These results indicated that coactivation of RTKs was essential in mesothelioma cell proliferation and/or survival, thus suggesting that simultaneous inhibition of RTKs may be a more effective strategy for the development of molecular target therapy for MPM.
authors.affiliation: Division of Molecular Oncology, Aichi Cancer Center Research Institute, 1-1 Kanokoden, Chikusa-ku, Nagoya, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Kawaguchi
authors.forename: Hideki
authors.initials: H
authors.lastname: Murakami
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Taniguchi
authors.forename: Makiko
authors.initials: M
authors.lastname: Fujii
authors.forename: Shigehisa
authors.initials: S
authors.lastname: Kawata
authors.forename: Takayuki
authors.initials: T
authors.lastname: Fukui
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kondo
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Osada
authors.forename: Noriyasu
authors.initials: N
authors.lastname: Usami
authors.forename: Kohei
authors.initials: K
authors.lastname: Yokoi
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Ueda
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Yatabe
authors.forename: Masafumi
authors.initials: M
authors.lastname: Ito
authors.forename: Yoshitsugu
authors.initials: Y
authors.lastname: Horio
authors.forename: Toyoaki
authors.initials: T
authors.lastname: Hida
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Sekido
mesh_terms: D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006801:Humans; D008654:Mesothelioma / Q000378:metabolism* / Q000473:pathology; D009361:Neoplasm Invasiveness; D010766:Phosphorylation; D010997:Pleural Neoplasms / Q000378:metabolism* / Q000473:pathology; D019859:Proto-Oncogene Proteins c-met / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D020797:Receptor, Platelet-Derived Growth Factor beta / Q000037:antagonists & inhibitors / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D015854:Up-Regulation
chemical_list: D066246:ErbB Receptors; D019859:Proto-Oncogene Proteins c-met; D018719:Erb-b2 Receptor Tyrosine Kinases; D020797:Receptor, Platelet-Derived Growth Factor beta; C508053:ERBB2 protein, human