title: In vivo therapeutic synergism of anti-epidermal growth factor receptor and anti-HER2 monoclonal antibodies against pancreatic carcinomas.
abstract: OBJECTIVE
  Pancreatic carcinoma is highly resistant to therapy. Epidermal growth factor receptor (EGFR) and HER2 have been reported to be both dysregulated in this cancer. To evaluate the in vivo effect of binding both EGFR and HER2 with two therapeutic humanized monoclonal antibodies (mAb), we treated human pancreatic carcinoma xenografts, expressing high EGFR and low HER2 levels.
  
  
  METHODS
  Nude mice, bearing xenografts of BxPC-3 or MiaPaCa-2 human pancreatic carcinoma cell lines, were injected twice weekly for 4 weeks with different doses of anti-EGFR (matuzumab) and anti-HER2 (trastuzumab) mAbs either alone or in combination. The effect of the two mAbs, on HER receptor phosphorylation, was also studied in vitro by Western blot analysis.
  
  
  RESULTS
  The combined mAb treatment significantly inhibited tumor progression of the BxPC-3 xenografts compared with single mAb injection (P = 0.006) or no treatment (P = 0.0004) and specifically induced some complete remissions. The two mAbs had more antitumor effect than 4-fold greater doses of each mAb. The significant synergistic effect of the two mAbs was confirmed on the MiaPaCa-2 xenograft and on another type of carcinoma, SK-OV-3 ovarian carcinoma xenografts. In vitro, the cooperative effect of the two mAbs was associated with a decrease in EGFR and HER2 receptor phosphorylation.
  
  
  CONCLUSIONS
  Anti-HER2 mAb has a synergistic therapeutic effect when combined with an anti-EGFR mAb on pancreatic carcinomas with low HER2 expression. These observations may open the way to the use of these two mAbs in a large panel of carcinomas expressing different levels of the two HER receptors.
authors.affiliation: Institut National de la Santé et de la Reserche Médicale, EMI 0227, Centre de Recherche en cancérologie de Montpellier, Université Montpellier I, France.
authors.forename: Christel
authors.initials: C
authors.lastname: Larbouret
authors.forename: Bruno
authors.initials: B
authors.lastname: Robert
authors.forename: Isabelle
authors.initials: I
authors.lastname: Navarro-Teulon
authors.forename: Simon
authors.initials: S
authors.lastname: Thèzenas
authors.forename: Maha-Zohra
authors.initials: MZ
authors.lastname: Ladjemi
authors.forename: Sébastien
authors.initials: S
authors.lastname: Morisseau
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Campigna
authors.forename: Frédéric
authors.initials: F
authors.lastname: Bibeau
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Mach
authors.forename: André
authors.initials: A
authors.lastname: Pèlegrin
authors.forename: David
authors.initials: D
authors.lastname: Azria
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents / Q000494:pharmacology; D002277:Carcinoma / Q000276:immunology*; D045744:Cell Line, Tumor; D004357:Drug Synergism; D066246:ErbB Receptors / Q000737:chemistry / Q000276:immunology*; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D010190:Pancreatic Neoplasms / Q000276:immunology*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000737:chemistry / Q000276:immunology*; D000068878:Trastuzumab
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D066246:ErbB Receptors; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab; C520777:matuzumab