title: Antitumor activity of a combination of trastuzumab (Herceptin) and oral fluoropyrimidine S-1 on human epidermal growth factor receptor 2-overexpressing pancreatic cancer.
abstract: The cytotoxic effect of trastuzumab in combination with oral fluoropyrimidine S-1 on human epidermal growth factor receptor 2 (HER2)-overexpressing human pancreatic cancer cell line TRG in vitro and in vivo was investigated. HER2 expression in TRG was analyzed by RT-PCR and flow cytometry. For in vitro experiments, 5-fluorouracil (5-FU) was used instead of S-1. In vivo studies were conducted with TRG xenografts in athymic mice. Trastuzumab (10 mg/kg) was administered intraperitoneally once a week for 4 weeks. S-1 (10 mg/kg) was administered orally 5 days a week for 4 weeks. The results showed that TRG cells were positive for HER2 mRNA and overexpressed HER2 protein. Either trastuzumab or 5-FU concentration-dependently inhibited the growth of TRG cells. The combination of trastuzumab and 5-FU resulted in a significant inhibition of growth of TRG cells compared to either agent alone (P<0.001). Incubation of TRG cells with peripheral blood mononuclear cells after treatment with trastuzumab enhanced the antiproliferative effect of trastuzumab, which could be the result of antibody-dependent cellular cytotoxicity. The combination of trastuzumab and S-1 resulted in a significant reduction in xenograft volume compared to each agent alone (P<0.0001). In conclusion, this study showed that combination therapy with trastuzumab and S-1 may be effective for HER2-overexpressing pancreatic cancer patients.
authors.affiliation: Department of General Surgery, Yokohama City University, Kanagawa 236-0004, Japan. saekihiroyuki@yahoo.co.jp
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Saeki
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Yanoma
authors.forename: Shouji
authors.initials: S
authors.lastname: Takemiya
authors.forename: Yukio
authors.initials: Y
authors.lastname: Sugimasa
authors.forename: Makoto
authors.initials: M
authors.lastname: Akaike
authors.forename: Norio
authors.initials: N
authors.lastname: Yukawa
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Rino
authors.forename: Toshio
authors.initials: T
authors.lastname: Imada
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000911:Antibodies, Monoclonal / Q000008:administration & dosage; D061067:Antibodies, Monoclonal, Humanized; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D018920:Coculture Techniques; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D066246:ErbB Receptors / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000187:drug effects; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D010094:Oxonic Acid / Q000008:administration & dosage; D010190:Pancreatic Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics*; D020893:Receptor, ErbB-3 / Q000235:genetics; D066247:Receptor, ErbB-4; D020133:Reverse Transcriptase Polymerase Chain Reaction; D005641:Tegafur / Q000008:administration & dosage; D000068878:Trastuzumab; D023041:Xenograft Model Antitumor Assays
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D004338:Drug Combinations; D066246:ErbB Receptors; D010094:Oxonic Acid; D012333:RNA, Messenger; D018719:Erb-b2 Receptor Tyrosine Kinases; D020893:Receptor, ErbB-3; D066247:Receptor, ErbB-4; D005641:Tegafur; D000068878:Trastuzumab; C079198:S 1 (combination); C587689:ERBB4 protein, human; C587690:Erbb4 protein, mouse