Antitumor mechanism of recombinant murine interleukin-12 vaccine

Effect of interleukin 12 gene therapy on microvessel density and microenvironment in a rabbit model of VX2 liver cancer

AIM: To evaluate the effect of interleukin-12 (IL-12) gene therapy on microvessel density and microenvironment in a post-chemoembolization VX2 liver cancer model, and to investigate its anti-tumor mechanism.

METHODS: Rabbits with VX2 hepatic tumors were randomized into 4 groups, with eight rabbits in each group. Interventional procedure protocols were performed as follows: 0.9% saline solution (group 1, control), transcatheter arterial chemoembolization alone (group 2, lipiodol + mitomycin), intra-arterial IL-12 gene infusion (group 3, IL-12 gene therapy alone), and intra-arterial IL-12 gene infusion in combination with chemoembolization (group 4, IL-12 plus chemoembolization). Fourteen days after therapy, tumor tissues of the sacrificed animals were explanted for immunohistochemistry to evaluate microvessel density, effector T cells (CD3⁺, CD4⁺, and CD8⁺) and regulatory T cells (FoxP3⁺).

RESULTS: The microvessel density and FoxP3⁺ T cells in group 2 were significantly higher than those in group 1, but the differences in CD3⁺, CD4⁺, and CD8⁺ T cells between the two groups were not significant. The microvessel density in gene therapy groups (groups 3 and 4) were significantly lower, and CD3⁺, CD4⁺, and CD8⁺ T cells in these two groups were significantly higher than those in groups 1 and 2. The differences in CD3⁺, CD4⁺, and CD8⁺ T cells between the two gene therapy groups (groups 3 and 4) were not significant. The difference in FoxP3⁺ T cells was not significant between before and after IL-12 gene therapy. The differences in the level of FoxP3 were not significant between groups 3 and 1, as well as between groups 4 and 2.

CONCLUSION: IL-12 gene therapy can inhibit angiogenesis and induce effector T cell (CD3⁺, CD4⁺, and CD8⁺) infiltration in the VX2 liver cancer model, but the efficacy appears to be limited by the regulatory T cells (FoxP3⁺) existing in the tumors and overexpressed after chemoembolization.

The relationship between the antitumor effect of the IL-12 gene therapy and the expression of Th1 cytokines in an HPV16-positive murine tumor model

Objective. The goal of the present study was to investigate the effect of IL-12 expressed in plasmid on the Th1 cytokine profile in an experimental HPV16-positive murine tumor model and the association with the IL-12's antitumor effect. Methods. Mice were injected with BMK-16/myc cells to establish HPV16-positive tumor and then pNGVL3-mIL-12 plasmid; pcDNA3 plasmid or PBS was injected directly into tumor site. The antitumor effect of the treatment was evaluated and the cytokines expression profile in each tumor tissue was analyzed. Results. Treatment with pNGVL3-mIL-12 plasmid had a significant antitumor effect, and a Th2-Th3-type cytokines prolife was detected in the murine tumor model with expression of the cytokines IL-10, IL-4, and TGF-β1. However, after the tumor was treated with three intratumoral injections of plasmid containing IL-12 cDNA, it showed a cytokine profile associated with Th1 with expression of IL-2, IL-12, and IFN-γ cytokines and reduced expression of IL-10, IL-4, and TGF-β1. Conclusions. The treatment with the IL-12 gene in the experimental HPV16-positive tumor model promoted the activation of the cellular immune response via expression of a Th1-type cytokine profile and was associated with the inhibition of tumor growth. Thus, IL-12 treatment represents a novel approach for gene therapy against cervical cancer.

Recombinant hepatitis B virus surface antigen formulated with B-type CpG oligodeoxynucleotide induces therapeutic immunity against hepatitis B virus surface antigen-expressing liver cancer cells in mice

To develop a therapeutic vaccine against hepatitis B virus surface antigen (HBsAg)-expressing liver cancer, we tried to prepare a vaccine by formulating recombinant HBsAg with BW006, a B type CpG oligodeoxynucleotide (ODN) with Th1-biasing activity, and examined its potency of inducing therapeutic immunity against HBsAg-expressing liver cancer cells in mice. When applied therapeutically, BW006 could assist HBsAg to induce vigorous immune responses capable of inhibiting the growth of HBsAg-expressing liver cancer cells and prolonging the survival of mice bearing HBsAg-expressing liver cancer cells. In vivo and in vitro experiments showed that the BW006-adjuvanted HBsAg enhanced the production of IgG2a antibodies, interferon-γ, and interleukin-12 and facilitated the generation of specific cytotoxic T lymphocyte that killed the HBsAg-expressing liver cancer cells. These results suggest that the BW006-adjuvanted HBsAg might be developed into a candidate tumor vaccine for the treatment of HBsAg-expressing liver cancer.

IL-21 and IL-12 inhibit differentiation of Treg and TH17 cells and enhance cytotoxicity of peripheral blood mononuclear cells in patients with cervical cancer

OBJECTIVES

Interleukin 21 (IL-21) and IL-12 have been known to be effective antitumor agents. In this study, we evaluated whether IL-21 in combination with IL-12 could enhance the cytotoxicity of peripheral blood mononuclear cells (PBMCs) in patients with cervical intraepithelial neoplasia III and cervical cancer.

METHODS

Peripheral blood mononuclear cells were isolated from peripheral blood of cervical intraepithelial neoplasia III patients (n = 17) and cervical cancer patients (n = 18). Peripheral blood mononuclear cells were cultured with IL-2 in low concentration as control group. Interleukin 2-stimulated PBMCs were cocultured with anti-human IL-21 neutralizing antibody, IL-21 alone, IL-12 alone, and IL-21 plus IL-12, respectively, as test groups. The cytotoxicity of PBMCs against SiHa tumor cells was examined by lactate dehydrogenase released assay. CD4CD25FOXP3 T regulatory (Treg) cells and CD4IL-17A T helper 17 (TH17) cells were analyzed by flow cytometry. Proliferation and apoptosis were detected by CCK-8 (cell counting kit 8) assay and flow cytometry, respectively.

RESULTS

Compared with controls, IL-21 and IL-12 significantly elevated PBMC cytotoxicity against SiHa cells. Moreover, IL-21 plus IL-12 significantly elevated PBMC cytotoxicity in comparison to IL-21 alone and IL-12 alone. We also found that IL-21 plus IL-12 significantly decreased Treg and TH17 cell proportion in comparison to controls. Notably, IL-21 plus IL-12 significantly decreased TH17 cell proportion in comparison to IL-21 alone. Both IL-21 and IL-12 significantly decreased the apoptosis rate of PBMCs, whereas neither IL-21 nor IL-12 had significant effect on PBMC proliferation.

CONCLUSIONS

The combination of IL-21 and IL-12 could efficiently stimulate PBMCs with cytotoxicity against SiHa cells, and the possible mechanisms may be due to down-regulated Treg and TH17 cell differentiation.

Molecular Mechanism and Potential Targets for Blocking HPV-Induced Lesion Development

Persistent infection with high-risk HPV is the etiologic agent associated with the development of cervical cancer (CC) development. However, environmental, social, epidemiological, genetic, and host factors may have a joint influence on the risk of disease progression. Cervical lesions caused by HPV infection can be removed naturally by the host immune response and only a small percentage may progress to cancer; thus, the immune response is essential for the control of precursor lesions and CC. We present a review of recent research on the molecular mechanisms that allow HPV-infected cells to evade immune surveillance and potential targets of molecular therapy to inhibit tumor immune escape.