title: Intratumoral injection of immature dendritic cells enhances antitumor effect of hyperthermia using magnetic nanoparticles.
abstract: Dendritic cells (DCs) are potent antigen-presenting cells that play a pivotal role in regulating immune responses in cancer and have recently been shown to be activated by heat shock proteins (HSPs). We previously reported that HSP70 expression after hyperthermia induces antitumor immunity. Our hyperthermia system using magnetite cationic liposomes (MCLs) induced necrotic cell death that was correlated with HSP70 release. In the present study, we investigated the therapeutic effects of DC therapy combined with MCL-induced hyperthermia on mouse melanoma. In an in vitro study, when immature DCs were pulsed with mouse B16 melanoma cells heated at 43 degrees C, major histocompatibility complex (MHC) class I/II, costimulatory molecules CD80/CD86 and CCR7 in the DCs were upregulated, thus resulting in DC maturation. C57BL/6 mice bearing a melanoma nodule were subjected to combination therapy using hyperthermia and DC immunotherapy in vivo by means of tumor-specific hyperthermia using MCLs and directly injected immature DCs. Mice were divided into 4 groups: group I (control), group II (hyperthermia), group III (DC therapy) and group IV (hyperthermia + DC therapy). Complete regression of tumors was observed in 60% of mice in group IV, while no tumor regression was seen among mice in the other groups. Increased cytotoxic T lymphocyte (CTL) and natural killer (NK) activity was observed on in vitro cytotoxicity assay using splenocytes in the cured mice treated with combination therapy, and the cured mice rejected a second challenge of B16 melanoma cells. This study has important implications for the application of MCL-induced hyperthermia plus DC therapy in patients with advanced malignancies as a novel cancer therapy.
authors.affiliation: Department of Biotechnology, School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan.
authors.forename: Kouji
authors.initials: K
authors.lastname: Tanaka
authors.forename: Akira
authors.initials: A
authors.lastname: Ito
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Tatsuyoshi
authors.initials: T
authors.lastname: Kawamura
authors.forename: Shinji
authors.initials: S
authors.lastname: Shimada
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Saida
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Honda
mesh_terms: D000818:Animals; D002412:Cations; D003713:Dendritic Cells / Q000276:immunology*; D055590:Electromagnetic Phenomena; D052203:Ferrosoferric Oxide; D018840:HSP70 Heat-Shock Proteins / Q000096:biosynthesis; D006979:Hyperthermia, Induced; D007501:Iron / Q000627:therapeutic use*; D008081:Liposomes; D008545:Melanoma / Q000628:therapy* / Q000662:veterinary; D051379:Mice; D049329:Nanostructures; D010087:Oxides / Q000627:therapeutic use*; D012878:Skin Neoplasms / Q000628:therapy* / Q000662:veterinary; D013602:T-Lymphocytes, Cytotoxic
chemical_list: D002412:Cations; D018840:HSP70 Heat-Shock Proteins; D008081:Liposomes; D010087:Oxides; D007501:Iron; D052203:Ferrosoferric Oxide