title: Dendritic cell therapy with interferon-alpha synergistically suppresses outgrowth of established tumors in a murine colorectal cancer model.
abstract: Both dendritic cell (DC)-based immunotherapy and interferon (IFN)-alpha therapy have been proved to have potent long-lasting antitumor effects. In anticipation of synergistic antitumor effects, we performed combination therapy with DCs and IFN-alpha gene-transduced murine colorectal cancer MC38 cells (MC38-IFN-alpha). DCs incubated with MC38-IFN-alpha, but not neomycin-resistance gene-transduced MC38 cells (MC38-Neo), effectively enhanced proliferation of allogeneic splenocytes in vitro. In 12 of 17 mice, DCs in combination with MC38-IFN-alpha prevented the development of a parental tumor, while DCs and MC38-Neo did in only three of 17 mice (P=0.008). In a therapeutic model of an established parental tumor, inoculation of DCs and MC38-IFN-alpha suppressed the growth of the established parental tumors significantly compared with the administration of DCs with MC38-Neo or naive splenocytes with MC38-IFN-alpha (P=0.016 and 0.024, respectively). Analyses of immunohistochemistry and tumor-infiltrating mononuclear cells showed that CD8(+), CD11c(+), and NK1.1(+) cells markedly infiltrated the established tumors of mice treated with DCs and MC38-IFN-alpha. From the results of observation of parental tumor outgrowth in immune cell-depleted mice, CD8(+) cells, and asialo-GM-1(+) cells were thought to contribute to the antitumor effects induced by the combination therapy. Furthermore, MC38-specific cytolysis was detected when splenocytes of mice inoculated with DCs and MC38-IFN-alpha cells were stimulated with MC38-IFN-alpha cells in vitro. Since DC-based immunotherapy in combination with IFN-alpha-expressing tumor cells induces potent antitumor cellular immune responses, it should be considered for clinical application.
authors.affiliation: Second Department of Internal Medicine, Showa University School of Medicine, Shinagawa-ku, Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Ishii
authors.forename: K
authors.initials: K
authors.lastname: Hiroishi
authors.forename: J
authors.initials: J
authors.lastname: Eguchi
authors.forename: A
authors.initials: A
authors.lastname: Hiraide
authors.forename: M
authors.initials: M
authors.lastname: Imawari
mesh_terms: D019264:Adoptive Transfer / Q000379:methods*; D000818:Animals; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000276:immunology / Q000628:therapy*; D003713:Dendritic Cells / Q000276:immunology*; D005260:Female; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors / Q000494:pharmacology; D007371:Interferon-gamma / Q000235:genetics* / Q000276:immunology; D008212:Lymphocyte Depletion; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D012190:Retroviridae / Q000235:genetics; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014161:Transduction, Genetic / Q000379:methods
chemical_list: D007371:Interferon-gamma