IL-12 Gene Therapy Is an Effective Therapeutic Strategy for Hepatocellular Carcinoma in Immunosuppressed Mice

Abstract

Immunosuppressive therapy for organ transplantation is essential for controlling rejection. When liver transplantation is performed as a therapy for hepatocellular carcinoma (HCC), recurrent HCC is one of the most fatal complications. In this study, we show that intratumoral murine IL-12 (mIL-12) gene therapy has the potential to be an effective treatment for malignancies under immunosuppression. C3H mice (H-2k), injected with FK506 (3 mg/kg) i.p., were s.c. implanted with 2.5 × 106 MH134 cells (H-2k) and we treated the established HCC with electroporation-mediated gene therapy using mIL-12 plasmid DNA. Intratumoral gene transfer of mIL-12 elevated intratumoral mIL-12, IFN-γ, and IFN-γ-inducible protein-10, significantly reduced the number of microvessels and inhibited the growth of HCC, compared with HCC-transferred control pCAGGS plasmid. The inhibition of tumor growth in immunosuppressed mice was comparable with that of mIL-12 gene therapy in immunocompetent mice. Intratumoral mIL-12 gene therapy enhanced lymphocytic infiltration into the tumor and elicited the MH134-specific CTL response even under FK506. The dose of FK506 was sufficient to prevent the rejection of distant allogenic skin grafts (BALB/c mice, H-2d) and tumors, B7-p815 (H-2d) used as transplants, during mIL-12 gene therapy against MH134. Ab-mediated depletion studies suggested that the inhibition of tumor growth, neovascularization, and spontaneous lung metastasis by mIL-12 was dependent almost entirely on NK cells and partially on T cells. These results suggest that intratumoral mIL-12 gene therapy is a potent effective strategy not only to treat recurrences of HCC in liver transplantation, but also to treat solid malignant tumors in immunosuppressed patients with transplanted organ.

Difference in cytotoxicity against hepatocellular carcinoma between liver and periphery natural killer cells in humans

“…The immunosuppressive regimen currently used after liver transplantation, consisting of tacrolimus/cyclosporine and methylprednisolone, reduces adaptive components of cellular immunity (predominantly T cell-mediated immune responses), while maintaining innate components of cellular immunity. 3,38,39 Because immune surveillance against tumors is mediated by both innate and adoptive components of cellular immunity, augmentation of NK cell responses to tumors, which have been thought to play a central role in innate immunity against tumors, might be a promising immunotherapy approach. Several therapeutic cytokines including IL-2 and IFNs primarily act through NK cells, and many studies have shown that activation of NK cell differentiation and function leads to a more efficient elimination of tumor growth [5][6][7][8][9] ; however, the systemic administration of those cytokines is likely associated with an acceleration of alloimmune responses leading to liver allograft rejection.…”

Induction of Efficient Antitumor Immunity Using Dendritic Cells Activated by Recombinant Sendai Virus and Its Modulation by Exogenous IFN-β Gene

“…Murine malignant melanoma B16F1 and B16F10 cells were purchased from American Culture Collections (ATCC). MH134, a murine hepatocellular carcinoma cell line, and X5563, a plasmacytoma cell line derived from C3H/HeN mice, were maintained as described (17). An NKsensitive lymphoma cell line, YAC-1, and a T cell lymphoma cell line of C57BL/6 mice origin, EL-4, were also purchased from ATCC.…”

In vivo silencing of a molecular target by short interfering RNA electroporation: tumor vascularization correlates to delivery efficiency

“…S2). 5 Harada et al used 10 pulses of a higher voltage (150 V/cm) and duration (50 ms) to deliver murine interleukin-12 plasmid injected into hepatocellular carcinomas using the same electroporator (CUY 21, Nepa Gene Co., Ltd.) but different electrodes consisting of a pair of needles (36). They applied severer electroporation conditions than ours because of the quite high resistance (1,620 F 90 V) in hepatocellular carcinomas with their needle-type electrodes (37).…”