title: ErbB3 expression promotes tumorigenesis in pancreatic adenocarcinoma.
abstract: Historically, ErbB3 has been overlooked within the ErbB receptor family due to its perceived lack of tyrosine kinase activity. We have previously demonstrated that in pancreatic cancer ErbB3 is the preferred dimerization partner of EGFR, ErbB3 protein expression level directly correlates with the anti-proliferative effect of erlotinib (an EGFR-specific tyrosine kinase inhibitor), and transient knockdown of ErbB3 expression results in acquired resistance to EGFR-targeted therapy. In this study, we develop a stable isogenic model of ErbB3 expression in an attempt to decipher ErbB3's true contribution to pancreatic cancer tumorigenesis and to examine how this receptor affects cellular sensitivity to EGFR-targeted therapy. Analysis of the EGFR-ErbB3 heterodimer demonstrates that ligand-induced PI3K-AKT signaling is limited to ErbB3-expressing cells and that this signaling cascade can be partially abrogated by inhibiting EGFR function with erlotinib. Using our model of exogenous ErbB3 expression we showed a direct relationship between ErbB3 protein levels and increased pancreatic cancer cell proliferation in vitro. In vivo, ErbB3(+)PANC-1 xenografts had a significantly larger tumor volume than PANC-1 control xenografts (ErbB3-PANC-1) and displayed increased sensitivity to EGFR-targeted therapy. In pancreatic cancer, ErbB3 appears to be critically involved in EGFR signaling as evidenced by its profound effect on cellular proliferation and its ability to influence response to EGFR-targeted therapy.
authors.affiliation: Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: J Spencer
authors.initials: JS
authors.lastname: Liles
authors.forename: Juan Pablo
authors.initials: JP
authors.lastname: Arnoletti
authors.forename: Ching-Wei D
authors.initials: CW
authors.lastname: Tzeng
authors.forename: J Harrison
authors.initials: JH
authors.lastname: Howard
authors.forename: Andrew V
authors.initials: AV
authors.lastname: Kossenkov
authors.forename: Peter
authors.initials: P
authors.lastname: Kulesza
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Heslin
authors.forename: Andrey
authors.initials: A
authors.lastname: Frolov
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D015153:Blotting, Western; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002867:Chromones / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000378:metabolism; D000069347:Erlotinib Hydrochloride; D005260:Female; D005419:Flavonoids / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051379:Mice; D016513:Mice, SCID; D009025:Morpholines / Q000494:pharmacology; D010190:Pancreatic Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011799:Quinazolines / Q000494:pharmacology; D034622:RNA Interference; D020893:Receptor, ErbB-3 / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects; D047368:Tumor Burden / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays
chemical_list: D002867:Chromones; D005419:Flavonoids; D009025:Morpholines; D047428:Protein Kinase Inhibitors; D011799:Quinazolines; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D000069347:Erlotinib Hydrochloride; D019869:Phosphatidylinositol 3-Kinases; D066246:ErbB Receptors; D020893:Receptor, ErbB-3; D051057:Proto-Oncogene Proteins c-akt; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one