Selective activation of insulin receptor substrate-1 and -2 in pleural mesothelioma cells: association with distinct malignant phenotypes.
Molecular mechanisms active in transforming human pleural cells remain incompletely understood. Our previous microarray analysis of malignant pleural mesothelioma revealed alterations in components of the insulin-like growth factor (IGF) system, implicating this signaling axis in tumorigenesis. Therefore, in this current study, we characterized the molecular phenotype and investigated the key signaling pathways of the IGF system in malignant pleural mesothelioma specimens. For the major IGF components, we assessed mRNA abundance and total protein levels. We measured IGF-I ligand-dependent activation of signaling pathways downstream of the type I IGF receptor in a subset of malignant pleural mesothelioma cell lines and determined the corresponding biological consequences. At the transcriptional level, we observed consistent changes in IGF components that may contribute to a malignant phenotype. IGF-I stimulation of cells resulted in enhanced activation of type I IGF receptor and IRS adaptor proteins. Differential activation of IRS-1 signaling was associated with cell growth, whereas IRS-2 signaling was associated with cell motility. Thus, these data suggest that multiple mechanisms likely contribute to malignant pleural mesothelioma tumorigenesis. Therefore, IGF system components represent novel malignant pleural mesothelioma therapeutic targets for investigation.
Hoang
Chuong D
CD
Division of Cardiovascular and Thoracic Surgery, Department of Surgery, University of Minnesota Medical School, Minneapolis, Minnesota, USA.
Zhang
Xihong
X
Scott
Paul D
PD
Guillaume
Tenner J
TJ
Maddaus
Michael A
MA
Yee
Douglas
D
Kratzke
Robert A
RA
D002461:Cell Line, Transformed; D015870:Gene Expression; D006801:Humans; D055504:Insulin Receptor Substrate Proteins; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology / Q000502:physiology; D047908:Intracellular Signaling Peptides and Proteins; D020935:MAP Kinase Signaling System; D008654:Mesothelioma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism*; D010997:Pleural Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D013002:Somatomedins / Q000096:biosynthesis / Q000235:genetics
C526292:IRS1 protein, human; C526297:IRS2 protein, human; D055504:Insulin Receptor Substrate Proteins; D047908:Intracellular Signaling Peptides and Proteins; D010750:Phosphoproteins; D012333:RNA, Messenger; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D019869:Phosphatidylinositol 3-Kinases