title: Intensification of antitumor effect by T helper 1-dominant adoptive immunogene therapy for advanced orthotopic colon cancer.
abstract: OBJECTIVE
  T helper (Th) 1/Th2 balance, controlled by Th1 or Th2 cells producing cytokines, plays important roles in antitumor immunity. Interleukin-18 (IL-18) can act together with IL-12 in promoting the generation of IFN-gamma producing Th1 cells. The goal of this study was to determine whether cytotoxic T lymphocyte (CTL) secreted in a murine IL-18-induced Th1-dominant state inhibited the development of primary tumors and synchronous liver metastases in orthotopic colon cancer model.
  
  
  METHODS
  Murine IL-18 gene was transduced into activated T lymphocytes by an adenovirus vector encoding IL-18 (AdIL-18) liposome complex method. Efficacy of adoptive immunogene therapy using AdIL-18 with or without IL-12 was tested in advanced orthotopic xenograft of murine colon cancer. To elucidate the mechanism responsible for the adoptive immunogene therapy, serum IL-4, IL-6, IFN-gamma, and tumor necrosis factor alpha production in Th1/Th2 cytokine balance and quantification of tumor vascularity were investigated.
  
  
  RESULTS
  By a modified method of adenoviral gene transduction, T lymphocytes achieved efficient IL-18 production without cell toxicity. Against orthotopic colon cancer, when combined with low dose of recombinant (r) IL-12 (AdIL-18-CTL/rIL-12), the therapeutic efficacy showed much smaller tumors with no liver metastases and no disseminated tumors. There was a significant difference in the volume of primary tumors and the number of liver metastases compared with the group treated with AdIL-18-CTL alone or other group (P < 0.01). In addition, the median survival time of the group treated with AdIL-18-CTL was 53.7 +/- 5.8 days and that of AdIL-18-CTL/rIL-12 was 78.4 +/- 6.1 days, which was also a significant difference (P < 0.01). These antitumor mechanisms were involved with Th1-dominant response in serum Th1/Th2 cytokine balance and suppression of neovascularization at primary tumor site.
  
  
  CONCLUSIONS
  These data suggest that a strategy of Th1/Th2 balance-based adoptive immunogene therapy might be useful for advanced cancer patients.
authors.affiliation: Second Department of Surgery, Wakayama Medical University, School of Medicine, Wakayama 641-8510, Japan.
authors.forename: Mikihito
authors.initials: M
authors.lastname: Nakamori
authors.forename: Makoto
authors.initials: M
authors.lastname: Iwahashi
authors.forename: Masaki
authors.initials: M
authors.lastname: Nakamura
authors.forename: Kentaro
authors.initials: K
authors.lastname: Ueda
authors.forename: Xiaoliu
authors.initials: X
authors.lastname: Zhang
authors.forename: Hiroki
authors.initials: H
authors.lastname: Yamaue
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D003110:Colonic Neoplasms / Q000628:therapy*; D005260:Female; D015316:Genetic Therapy; D016219:Immunotherapy, Adoptive; D020382:Interleukin-18 / Q000096:biosynthesis / Q000235:genetics*; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D009389:Neovascularization, Pathologic / Q000517:prevention & control; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D018417:Th1 Cells / Q000276:immunology*; D014161:Transduction, Genetic
chemical_list: D020382:Interleukin-18