title: Epidermal growth factor receptor and HER-3 restrict cell response to sorafenib in hepatocellular carcinoma cells.
abstract: OBJECTIVE
  Sorafenib is the standard of care for the treatment of advanced hepatocellular carcinoma (HCC). However, primary and acquired resistance is observed in patients. We examined whether gefitinib, which inhibits both epidermal growth factor receptor (EGFR) and HER-3 phosphorylation, could improve HCC cell response to sorafenib.
  
  
  METHODS
  Sorafenib and gefitinib were tested in HCC tumor xenografts and in sorafenib-sensitive and sorafenib-resistant HCC cell lines. Biomarkers relevant to the HER system were analyzed by Western blotting and ELISA. RNA interference was used to downregulate the HER system. Amphiregulin concentrations were measured by ELISA in sera from patients under sorafenib treatment.
  
  
  RESULTS
  Sorafenib combined with gefitinib significantly inhibited tumor growth in mice and reduced cell viability in vitro compared to single agents. In cell lines cultured in 10% serum or treated with EGF, sorafenib alone inhibited phospho-STAT3 while it maintained or even increased phospho-ERK and/or phospho-AKT. The paradoxical effects of sorafenib were prevented by gefitinib or by downregulation of EGFR and HER-3 expression. In cells with acquired resistance to sorafenib, aberrant activation of EGFR/HER-3 receptors as well as overexpression of several EGFR ligands were observed. These enhanced autocrine/paracrine loops led to the constitutive activation of ERK and AKT and conferred increased sensitivity to gefitinib. Increased serum concentrations of amphiregulin were observed in 10 out of 14 patients under sorafenib treatment compared to baselines.
  
  
  CONCLUSIONS
  Signaling pathways controlled by EGFR and HER-3 restrict sorafenib effects both in naive and sorafenib-resistant HCC cells. Consequently, gefitinib cooperates with sorafenib to increase antiproliferative response and to prevent resistance.
authors.affiliation: UPMC Univ Paris 06, UMR_S 938, F-75012 Paris, France.
authors.forename: Marie-José
authors.initials: MJ
authors.lastname: Blivet-Van Eggelpoël
authors.forename: Hamza
authors.initials: H
authors.lastname: Chettouh
authors.forename: Laetitia
authors.initials: L
authors.lastname: Fartoux
authors.forename: Lynda
authors.initials: L
authors.lastname: Aoudjehane
authors.forename: Véronique
authors.initials: V
authors.lastname: Barbu
authors.forename: Colette
authors.initials: C
authors.lastname: Rey
authors.forename: Sabrina
authors.initials: S
authors.lastname: Priam
authors.forename: Chantal
authors.initials: C
authors.lastname: Housset
authors.forename: Olivier
authors.initials: O
authors.lastname: Rosmorduc
authors.forename: Christèle
authors.initials: C
authors.lastname: Desbois-Mouthon
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D066258:Amphiregulin; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001557:Benzenesulfonates / Q000494:pharmacology* / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000378:metabolism; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D019008:Drug Resistance, Neoplasm / Q000502:physiology; D066255:EGF Family of Proteins; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000378:metabolism*; D005260:Female; D000077156:Gefitinib; D006023:Glycoproteins / Q000378:metabolism; D056945:Hep G2 Cells; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D008114:Liver Neoplasms, Experimental / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology; D008297:Male; D051379:Mice; D008819:Mice, Nude; D008875:Middle Aged; D009536:Niacinamide / Q000031:analogs & derivatives; D010671:Phenylurea Compounds; D011725:Pyridines / Q000494:pharmacology* / Q000627:therapeutic use; D011799:Quinazolines / Q000494:pharmacology; D020893:Receptor, ErbB-3 / Q000378:metabolism*; D000077157:Sorafenib; D023041:Xenograft Model Antitumor Assays
chemical_list: C587848:AREG protein, human; D066258:Amphiregulin; D000970:Antineoplastic Agents; C587849:Areg protein, mouse; D001557:Benzenesulfonates; D014408:Biomarkers, Tumor; D066255:EGF Family of Proteins; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; D010671:Phenylurea Compounds; D011725:Pyridines; D011799:Quinazolines; D009536:Niacinamide; D000077157:Sorafenib; D066246:ErbB Receptors; D020893:Receptor, ErbB-3; D000077156:Gefitinib