Long-lasting gene expression by particle-mediated intramuscular transfection modified with bupivacaine: combinatorial gene therapy with IL-12 and IL-18 cDNA against rat sarcoma at a distant site

Abstract

The immune response is modulated by genetic adjuvants using plasmid vectors expressing cytokines. Skeletal muscle can express a foreign gene intramuscularly administered via a needle injection, and the potential of muscle as a target tissue for somatic gene therapy in treating cancer has been explored. In the present study, we investigated the efficacy of particle-mediated intramuscular transfection modified with a local anesthetic agent, bupivacaine, on luciferase and green fluorescent protein. The results indicate that these proteins are more efficiently expressed and persist longer in muscle modified in this way compared with the needleinjection method. Using an established rat sarcoma model, particle-mediated intramuscular gene-gun therapy with a combination of IL-12 and IL-18 cDNA was conducted. Growth of the distant sarcoma was significantly inhibited by particle-mediated intramuscular combination gene therapy, and the survival rate was also improved. Furthermore, the combination gene-gun therapy maintained significant levels of interferon-g and induced a high activity of tumor-specific cytotoxic T lymphocytes. These results suggest that the sustained local delivery of IL-12 and IL-18 cDNA using intramuscular gene-gun therapy modified with bupivacaine can induce long-term antitumor immunity, and can provide the great advantage of inhibiting the disseminated tumor.

Local and systemic antitumor effect of intratumoral and peritumoral IL-12 electrogene therapy on murine sarcoma

“…7 Nonviral delivery methods, which were employed in similar experiments on sarcomas, include intramuscular and intravenous injections of plasmid DNA alone and intramuscular bioballistic gene delivery. [9][10][11] Even though significant growth delay of tumor nodules was achieved using these techniques, long-term complete responses in animals were either not achieved or they were low, reaching up to 40% of treated animals after intramuscular IL-12 gene delivery using a gene gun in rat sarcoma. 11 These studies produced a comparable direct antitumor effect to peritumoral delivery in our study and drastically lower efficiency compared to intratumoral EGT.…”

“…[9][10][11] Even though significant growth delay of tumor nodules was achieved using these techniques, long-term complete responses in animals were either not achieved or they were low, reaching up to 40% of treated animals after intramuscular IL-12 gene delivery using a gene gun in rat sarcoma. 11 These studies produced a comparable direct antitumor effect to peritumoral delivery in our study and drastically lower efficiency compared to intratumoral EGT. It has already been established that use of naked plasmid DNA alone or bioballistic gene delivery (gene gun) yield lower transfection efficiency compared to use of electrotransfection.…”

“…17,18 Additionally, one of the major disadvantages of the gene gun technique is limitation of gene transfection only to superficial tissues. 39 Therefore, in the case of intramuscular bioballistic delivery of IL-12, surgical exposure of skeletal muscle had to be performed, 11 which makes this technique an invasive procedure, compared to the noninvasive nature of intra-and peritumoral EGT.…”

“…11 This nonviral technique produced serum concentrations of both IL-12 and IFNγ around for determination of intratumoral and serum concentrations of IL-12 and IFNγ.…”

“…Therefore, as a safer alternative method of gene delivery, different nonviral techniques are being investigated. Among them only a few were evaluated for antitumor efficiency in sarcoma, including use of naked plasmid DNA, 9,10 gene gun 11 and polyethylimine DNA vector. [12][13][14] Although they resulted in regression of tumor growth, induction of long-lasting antitumor immunity and eradication of induced lung metastases, they elicited a poorer therapeutic effect compared to viral IL-12 delivery.…”