Growth inhibition of human glioma cells by superinduced human interferon-beta

Suppression of cancer growth in mice by adeno-associated virus vector-mediated IFN-beta expression driven by hTERT promoter

Adeno-associated virus (AAV) has rapidly become a promising gene delivery vehicle for its excellent advantages of non-immunogenic, low pathogenicity and long-term gene expression in vivo. However, a major obstacle in development of effective AAV vector is the lack of tissue specificity, which caused low efficiency of AAV transfer to target cells. The application of human telomerase reverse transcriptase (hTERT) promoter is a prior targeting strategy for AAV in cancer gene therapy as hTERT activity is transcriptionally upregulated in most cancer cells. In the present work, we investigated whether AAV-mediated human interferon beta (IFN-beta) gene driven by hTERT promoter could specifically express in tumor cells and suppress tumor cell growth. Our data demonstrated that hTERT promoter-driven IFN-beta expression was the tumor-specific, decreased the cell viability of tumor cells but not normal cells, and induced tumor cell apoptosis via activation of caspase pathway and release of cytochrome c. AAV-mediated IFN-beta expression driven by hTERT promoter significantly suppressed the growth of colorectal cancer and lung cancer xenograft in mice and resulted in tumor cells death in vivo. These data suggested that AAVs in combination with hTERT-mediated IFN-beta expression could exert potential antitumor activity and provide a novel targeting approach to clinical gene therapy of varieties of cancers.

Interferon-beta gene therapy for cancer: basic research to clinical application

Interferon-beta gene therapy for cancer is the first such protocol developed in Japan. Here we describe the development process of our interferon-beta gene therapy from basic research to clinical application. Interestingly, the biological and biochemical characteristics of interferon-beta gene therapy through transfer of the interferon-beta gene into tumor cells by means of cationic liposomes differed from those of conventional interferon-beta protein therapy. Interferon-beta gene transfer could induce apoptosis in interferon-beta protein-resistant tumor cells, such as glioma, melanoma, and renal cell carcinoma. Induction of apoptosis was related to the level of intracellular mRNA of interferon-beta, prolongation of the phosphorylation time of molecules in the interferon-beta signal transduction pathway, such as JAK1, Trk2, and STAT1, and activation of DNase gamma. In our preclinical study we developed lyophilized cationic liposomes containing interferon-beta gene (gene drug) for clinical use and confirmed their safety. Thereafter, we performed a pilot clinical trial in patients with malignant glioma and confirmed the safety and effectiveness of this interferon-beta gene therapy. In this review we also comment on the status of gene therapy regulation in Japan. Interferon-beta gene therapy is expected to become widely available for clinical use in cancer patients, and this new strategy might be extended to molecular targeting therapy, or used in combination with cell therapy or other therapies.

Effective induction of antiglioma cytotoxic T cells by coadministration of interferon-beta gene vector and dendritic cells

As type I interferons (IFNs) enhance the stimulatory activity of dendritic cells (DCs), we hypothesized that transfection of glioma cells with the IFN-beta gene in the presence of DCs would provide particularly effective antitumor activity by both facilitating apoptosis of glioma cells and presenting the resulting glioma antigens to T cell by DCs, thereby inducing specific T-cell responses against glioma cells. A mouse glioma cell line 203G was first transfected with cDNA encoding IFN-beta using cationic liposomes, then cocultured with syngeneic bone marrow-derived DCs and naïve splenic T cells. The 203G cells were almost completely killed following 96-hour coculture with DCs and T cells, and strong tumor-specific cytotoxic T-lymphocyte (CTL) activity accompanied by high level interleukin (IL)-12 and IFN-gamma production was observed in culture. In addition, omission of either IFN-beta gene delivery, DCs or T cells from the coculture completely abrogated the induction of the CTL activity, suggesting that the combination of these components was required to elicit an optimal effect. On the basis of these in vitro data, syngeneic animals bearing subcutaneous 203G tumors received intratumoral injections of IFN-beta gene and DCs. Suppression of the tumor growth by this combinational therapy was superior to treatment with DC or IFN-beta gene solely. This combination may constitute a new therapeutic strategy to induce potent antiglioma immune responses.