Intratumoral rIL2-based immunotherapy in B16 melanoma

Functional and molecular characterization of interleukin-2 transgenic Ewing tumor cells for in vivo immunotherapy

BACKGROUND

Interleukin-2 (IL-2) is a potent cytokine with potential activity against several tumors including Ewing tumors (ET). Side effects of systemic IL-2 can be circumvented by the use of transgenic tumor cells. However, in vitro manipulation may change the overall gene expression profile of tumor cells unfavorably. Therefore, we assessed gene expression profiles, safety, and immunomodulatory efficacy of IL-2 transgenic (IL-2-tg) ET cells in vitro and in NOD/scid mice.

PROCEDURE

Viable wild type A673 tumor cells were co-cultured together with irradiated IL-2-tg or mock-transfected cells and HLA matched peripheral blood mononuclear cells. Activation of T and NK cells was assessed by FACS analysis. The effect of irradiated IL-2-tg cells on tumor growth in vivo was investigated by using NOD/scid mice. Gene expression profiles of wild type and transfected cells were analyzed with Affymetrix HG-U95A microarrays.

RESULTS

IL-2-tg cells activated and increased the number of T cells and NK cells in vitro. Co-culture with IL-2-tg but not with mock-transfected cells almost completely suppressed wild type tumor cell growth in vitro. Cell depletion experiments indicated a major contribution of NK cells to this tumor cell suppression. Co-transfer of irradiated IL-2-tg cells significantly reduced wild type tumor growth in NOD/scid mice. Side effects in the treated animals were not observed and no tumor growth was observed after injection of irradiated IL-2-tg cells alone. Gene expression profiling revealed a substantial degree of homogeneity of gene expression in transfected and wild type cells and suggests that transfection and selection procedures had no major impact on the gene expression profile.

CONCLUSIONS

Next to a high degree of homogeneity between transgenic and wild type cells, our data suggest that irradiated IL-2-tg ET cells can activate cytolytic effector cells. These cells may have therapeutic potential for ET patients.

Therapeutic efficiency of IL-2 gene transduced tumor vaccine for head and neck carcinoma

Transduction of the human interleukin-2 (IL-2) gene into tumor cells was carried out in order to develop a new immunotherapy for advanced head and neck carcinomas with a poor outcome. We transduced the IL-2 gene into KB cells, a head and neck squamous cell carcinoma cell line, using a defective herpes simplex viral (HSV) amplicon vector as a gene transfer vehicle. A high level of IL-2 was secreted by IL-2 gene-transduced KB cells (KB/IL-2). The IL-2 producibility of irradiated KB/IL-2 cells was almost the same as that of non-irradiated cells. In the tumor establishment model in nude mice, IL-2 and interferon-gamma (IFN-gamma) at high concentrations were detected in the sera of mice transplanted with KB/IL-2 cells. The spleen cells of nude mice transplanted with KB/IL-2 cells exhibited high cytotoxic activity compared to those from mice transplanted with KB cells and from untreated mice. Three of five mice transplanted with KB/IL-2 cells rejected tumors. In the treatment of established tumors, therapeutic effects due to irradiated KB/IL-2 were dose-dependent. The suppressive effects on tumor growth were blocked by anti-asialo GM1, anti-human IL-2 and anti-IFN-gamma antibodies. Immunohistochemical observation revealed the presence of asialo GM1(+) cells among the KB/IL-2 cells in tumors transplanted into nude mice.

Intratumoral injection of an adenovirus expressing interleukin 2 induces regression and immunity in a murine breast cancer model

Rodent tumor cells engineered to secrete cytokines such as interleukin 2 (IL-2) or IL-4 are rejected by syngeneic recipients due to an enhanced antitumor host immune response. An adenovirus vector (AdCAIL-2) containing the human IL-2 gene has been constructed and shown to direct secretion of high levels of human IL-2 in infected tumor cells. AdCAIL-2 induces regression of tumors in a transgenic mouse model of mammary adenocarcinoma following intratumoral injection. Elimination of existing tumors in this way results in immunity against a second challenge with tumor cells. These findings suggest that adenovirus vectors expressing cytokines may form the basis for highly effective immunotherapies of human cancers.

Management of recurrent cutaneous melanoma

Recurrent melanoma occurs in approximately one third of patients treated for cutaneous melanoma. Although the majority of recurrence occurs within the first few years of primary therapy, a significant number remains at risk beyond 10 years. With rising incidence of recurrent melanoma in Western countries, physicians will undoubtedly face the challenge of managing these patients with the limited therapeutic options currently available. Once melanoma has recurred, the overall prognosis is poor. Localized disease is best treated with complete resection, if indicated. Our existing armamentarium for systemic treatment falls short of altering the course of natural history of melanoma, but regional chemotherapy is an effective modality for in-transit disease and satellitosis. Translational research in molecular genetics and immunology will fuel new ideas for the design of rational strategies toward tumor eradication. Ongoing trials that use gene-modified melanoma cells have begun a new chapter in cancer therapeutics and lend us a closer examination of bench-top science at the bedside.