title: Combination electro-gene therapy using herpes virus thymidine kinase and interleukin-12 expression plasmids is highly efficient against murine carcinomas in vivo.
abstract: We report the use of plasmid DNA-mediated combination gene therapy for tumor-bearing mice using in vivo electroporation, also called electro-gene therapy (EGT), that resulted in uncomplicated and complete cures in more than 90% of the mice. Subcutaneously inoculated CT26 tumors in syngeneic BALB/c mice were subjected to repeated EGT treatments consisting of intratumoral co-injection of naked plasmids encoding the cytokine interleukin-12 (IL-12) (p35 and p40 subunits) and the suicide gene herpes simplex virus thymidine kinase (HSV-tk), followed by in vivo electroporation. The early anti-tumor effect was always stronger, and the rate of cure, as seen in the long-term follow-up, was always greater in the groups treated with combination EGT than in those treated with IL-12 or HSV-tk EGT alone. Systemic levels of IL-12 and IFN-gamma increased in both combination and IL-12-alone EGT-treated groups. Moreover, combination EGT for established subcutaneous tumors strongly reduced hematogenous lung metastases and increased survival time when live CT26 tumor cells were injected through the tail vein. Limited experiments on C57/B16 mice with murine melanoma also showed very similar trends. These results suggest that this simple and safe method of plasmid-mediated combination EGT may provide a potentially effective gene therapy for cancer.
authors.affiliation: Department of Neurosurgery, Saiseikai Kumamoto Hospital, 5-3-1 Chikami, Kumamoto 861-4193, Japan.
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Goto
authors.forename: Toru
authors.initials: T
authors.lastname: Nishi
authors.forename: Osamu
authors.initials: O
authors.lastname: Kobayashi
authors.forename: Takahiko
authors.initials: T
authors.lastname: Tamura
authors.forename: Sukhendu B
authors.initials: SB
authors.lastname: Dev
authors.forename: Hideo
authors.initials: H
authors.lastname: Takeshima
authors.forename: Masato
authors.initials: M
authors.lastname: Kochi
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Kuratsu
authors.forename: Tsuneaki
authors.initials: T
authors.lastname: Sakata
authors.forename: Yukitaka
authors.initials: Y
authors.lastname: Ushio
mesh_terms: D000818:Animals; D002277:Carcinoma / Q000556:secondary / Q000628:therapy*; D004359:Drug Therapy, Combination; D018274:Electroporation; D018014:Gene Transfer Techniques; D015316:Genetic Therapy / Q000379:methods*; D007371:Interferon-gamma / Q000032:analysis; D018664:Interleukin-12 / Q000032:analysis / Q000235:genetics*; D008175:Lung Neoplasms / Q000473:pathology / Q000556:secondary / Q000628:therapy; D051379:Mice; D008807:Mice, Inbred BALB C; D010957:Plasmids / Q000235:genetics; D018139:Simplexvirus / Q000201:enzymology / Q000235:genetics; D013937:Thymidine Kinase / Q000235:genetics*
chemical_list: D018664:Interleukin-12; D007371:Interferon-gamma; D013937:Thymidine Kinase