title: Combination of interleukin-12 gene therapy, metronomic cyclophosphamide and DNA cancer vaccination directs all arms of the immune system towards tumor eradication.
abstract: In this work a combination therapy that acts upon the immune suppressive, the innate and specific arms of the immune system is proposed. This combination therapy, which consists of intratumoral interleukin-12 (IL-12) gene therapy, human tyrosinase (hTyr) DNA vaccination and metronomic cyclophosphamide (CPX), was evaluated in a B16-F10 mouse model. The following groups were compared: (1) no treatment, (2) control vector, (3) intratumoral IL-12 gene therapy, (4) intratumoral IL-12 gene therapy+metronomic CPX, (5) intratumoral IL-12 gene therapy+metronomic CPX+hTyr DNA vaccination. Next to clinical efficacy and safety, we characterized acute effects of IL-12 and anti-tumor immune response after a second tumor challenge. All treatment groups showed increased survival and higher cure rates than control groups. Survival of non-cured mice was increased when metronomic CPX was combined with IL-12 gene therapy. Furthermore, mice that received metronomic CPX had significantly lower percentages of regulatory T cells. Addition of the hTyr DNA vaccine increased cure rate and resulted in increased survival compared to other treatment groups. We also demonstrated that the manifest necrosis within days after IL-12 gene therapy is at least partly due to IL-12 mediated activation of NK cells. All cured mice were resistant to a second challenge. A humoral memory response against the tumor cells was observed in all groups that received IL-12 gene therapy, while a cellular memory response was observed only in the vaccinated mice. In conclusion, every component of this combination treatment contributed a unique immunologic trait with associated clinical benefits.
authors.affiliation: Laboratory of Gene Therapy, Department of Nutrition, Genetics and Ethology, Faculty of Veterinary Medicine, Ghent University, Heidestraat 19, B-9820 Merelbeke, Belgium.
authors.forename: Sofie
authors.initials: S
authors.lastname: Denies
authors.affiliation: Laboratory of Gene Therapy, Department of Nutrition, Genetics and Ethology, Faculty of Veterinary Medicine, Ghent University, Heidestraat 19, B-9820 Merelbeke, Belgium.
authors.forename: Laetitia
authors.initials: L
authors.lastname: Cicchelero
authors.affiliation: Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Albert Baertsoenkaai 3, B-9000 Gent, Belgium.
authors.forename: Isabel
authors.initials: I
authors.lastname: Van Audenhove
authors.affiliation: Laboratory of Gene Therapy, Department of Nutrition, Genetics and Ethology, Faculty of Veterinary Medicine, Ghent University, Heidestraat 19, B-9820 Merelbeke, Belgium. Electronic address: Niek.Sanders@UGent.be.
authors.forename: Niek N
authors.initials: NN
authors.lastname: Sanders
mesh_terms: D000818:Animals; D018906:Antineoplastic Agents, Alkylating / Q000008:administration & dosage; D019496:Cancer Vaccines; D003131:Combined Modality Therapy; D003520:Cyclophosphamide / Q000008:administration & dosage*; D016207:Cytokines / Q000276:immunology; D015316:Genetic Therapy; D006801:Humans; D018664:Interleukin-12 / Q000097:blood / Q000235:genetics*; D051379:Mice; D014442:Monophenol Monooxygenase / Q000235:genetics; D009369:Neoplasms / Q000276:immunology / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology; D047368:Tumor Burden; D019444:Vaccines, DNA
chemical_list: D018906:Antineoplastic Agents, Alkylating; D019496:Cancer Vaccines; D016207:Cytokines; D019444:Vaccines, DNA; D018664:Interleukin-12; D003520:Cyclophosphamide; D014442:Monophenol Monooxygenase
keywords: Immunotherapy; Interleukin-12; Melanoma; Metronomic chemotherapy; Tyrosinase vaccine