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Purpose: To investigate the specific antitumor responses against autologous hepatocellular carcinoma (HCC) cells of dendritic cells (DCs) fused with allogeneic HCC cell line, and evaluated the feasibility of BEL7402 as an alternative strategy to deliver shared HCC antigens to DCs. Methods: Previous studies demonstrated fusions of patient-derived DCs and autologous tumor cells could induce T-cell responses against autologous tumors. These fusion cells require patient-derived tumor cells, which are not, however, always available. Here, we report the fusing of autologous DCs with allogeneic HCC cell line to induced cytotoxic T-lymphocyte (CTL) response against autologous HCC cells compare with autologous tumor cells. Results: These DC/ BEL7402 fusion cells co-expressed tumor-associated antigens and DC-derived costimulatory and major histocompatibility complex molecules. Both CD4+ and CD8 T+ cells were activated by the fusion cells as demonstrated by the proliferation of T-cells, the production of cytokines and the simultaneous induction of specific CTL responses. Significantly, CTL induced by dendritic cell/allogeneic BEL7402 fusion cells were able to kill autologous HCC cells by human leukocyte antigen-A2 restricted mechanisms. The results did not show significant difference between DC fusion with autologous hepatocellular carcinoma cells and DC fusion with allogeneic hepatocellular carcinoma cell line. Conclusions: The fusion of allogeneic HCC cell line and autologous DCs may have applications in antitumor immunotherapy through cross-priming against shared tumor antigens and may provide a platform for adoptive immunotherapy. [ABSTRACT FROM AUTHOR]

Abstract: Recently, studies on dendritic cell (DC) vaccine have focused on the development of more effective DC vaccine regimen, such as the application of multiple tumor-associated antigen–targeted DC vaccine. This approach could be used to enhance efficacy of DC-based vaccine against tumors and infectious diseases. In this study, we analyzed whether DC from patients with hepatocellular carcinoma can be infected with the α-fetoprotein (AFP) gene and/or HBsAg gene (hepatocellular carcinoma–related antigen). Further, it was examined whether vaccination using these genetically engineered DC can induce stronger therapeutic antitumor immunity. Results revealed that DC infected with AdAFP (adenovirus AFP)/HBsAg can express AFP and HBsAg by reverse transcription–polymerase chain reaction and Western blot techniques. Compared with those before transfection, the expressions of membrane molecules increased dramatically. Specific T cells generated by DCs infected with AdAFP/HBsAg specifically recognized human leukocyte antigen–matched HepG2.2.15 cell lines. Moreover, the cytotoxic activity of cytotoxic T lymphocytes against HepG2.2.15 with DCs expressing AFP was significantly augmented by coinfection with the HBsAg gene. Administration with such vaccine also significantly increased the production of interleukin-12p70 and interferon-γ. Most importantly, in vivo results suggested that inhibitors of tumor growth were most significant in severe combined immunodeficiency mice model, which was treated with induced cytotoxic T lymphocyte by the AFP/HBsAg-DC vaccine. These results indicate that a vaccination therapy using DCs coinfected with the two tumor-associated antigen genes is an effective strategy for immunotherapy in the activation of DCs, CD4+ T cells, and CD8+ T cells, and may be useful in the clinical application of cancer vaccine therapy. [Copyright &y& Elsevier]

Abstract: Fusions of patient-derived dendritic cells (DCs) and autologous tumor cells induce T-cell responses against autologous tumors in animal models and human clinical trials. These fusion cells require patient-derived tumor cells, which are not, however, always available. Here we fused autologous DCs from patients with hepatocellular carcinoma (HCC) to an allogeneic HCC cell line (HepG2). These fusion cells co-expressed tumor-associated antigens (TAAs) and DC-derived costimulatory and MHC molecules. Both CD4+ and CD8+ T cells were activated by the fusion cells. Cytotoxic T lymphocytes (CTLs) induced by the fusion cells were able to kill autologous HCC by HLA-A2- and/or HLA-A24-restricted mechanisms. CTL activity against shared TAAs indicates that the presence of alloantigens does not prevent the development of CTLs with activity against autologous HCC cells. These fusion cells may have applications in anti-tumor immunotherapy through cross-priming against shared tumor antigens and may provide a platform for adoptive immunotherapy. [Copyright &y& Elsevier]

Abstract: The T-helper 1 (Th1) immune reaction is most important in dendritic cell (DC)–based immunotherapy. Interleukin (IL)–18, a Th1-biasing cytokine, plays a pivotal role in inducing cytotoxic T lymphocyte (CTL) responses. In this study, we analyzed whether dendritic cells (DCs) from patients with hepatocellular carcinoma (HCC) can be transduced with the IL-18 gene and/or α-fetoprotein (AFP) gene, and we examined whether vaccinations using these genetically engineered DC can induce stronger therapeutic antitumor immunity. The results showed that DC transfected with AdIL-18/AFP can expressed IL-18 and AFP by reverse transcriptase–polymerase chain reaction and enzyme-linked immunoassay. Compared with those before transfection, the expressions of membrane molecules were increased dramatically. Specific T cells generated by DC transfected with AdIL-18/AFP recognized HLA-matched HepG2 cell lines specifically. Most importantly, The cytotoxic activity of CTLs against HepG2 with DC expressing AFP(AFP-DC) was significantly augmented by co-transduction with the IL-18 gene. Administration with such vaccine also significantly increased the production of interleukin-12p70 and interferon-γ. These results indicate that a vaccination therapy using DC co-transduced with the TAA gene and IL-18 genes is effective strategy for immunotherapy in terms of the activation of DCs, CD4+ T, cells and CD8+ T cells, and may be useful in the clinical application of a cancer vaccine therapy. [Copyright &y& Elsevier]

Abstract: Dendritic cells (DCs) are professional antigen presenting cells that are being considered as potential immunotherapeutic agents to promote host immune responses against tumor antigens. The use of such modified antigen-presenting cells for research or therapeutic have been limited by several factors, including maintaining DCs in a highly activated state, efficient transduction and expression, stable expression, identification of appropriate tumor-associated antigens, and absence of unintended functional changes or cytotoxicity. In this study, the feasibility of using CD34-DCs for tumor immunotherapy after transduction with a recombinant adenovirus containing HBsAg gene (AdVHBsAg), an HCC-associated antigen, was investigated. The gene transfer with recombinant adenovirus vectors (AdV) can obtained high levels of stable expression of HBsAg and its efficiency was increased in a multiplicity of infection (MOI)-dependent manner. Moreover, the AdVHBsAg infection had no appreciable effect on apoptosis of DCs compared with that of mock-infected DCs. The T cell lines, primed by the recombinant AdVHBsAg-infected DCs in vitro, recognized HBsAg-expressing tumor cell lines in a human leukocyte antigen (HLA) class I-restricted manner, and evoked a higher CTL response, which indicated that high potent and specific antitumor immune response could be induced by AdVHBsAg DC vaccine. It may be a promising the therapeutic modality for the treatment of HBsAg-expressing tumors, and will be a foundation for further study on DC vaccines and gene therapy for HCC. [Copyright &y& Elsevier]