Co-delivery of IL-12/IL-15/IL-18 engineered DC vaccines with anti-IL-10R and nanoconjugated methotrexate in melanoma

In an immunosuppressive microenvironment created by melanoma cells, interleukin (IL)-10 can promote tumor growth and impair the function of antigen-presenting cells, particularly dendritic cells. One of the leading strategies to counteract IL-10's action is the administration of antibodies against its receptor. The tumor microenvironment can also be modulated by cytokines and/or cellular vaccines such as modified dendritic cells that overproduce IL-12, IL-15/IL-15Rα, and IL-18. These cellular vaccines serve as a source of cytokines and stimulate the immune system by presenting tumor antigens to lymphocytes. Furthermore, the efficacy of the dendritic cell vaccine can be achieved through the nanoconjugate of methotrexate and hydroxyethyl starch (HES-MTX), which reduces the activity of IL-10 and eliminates immunosuppressive cells.

Two experiments were conducted: one focusing on immunotherapy and the other on chemoimmunotherapy. The immunotherapy involved two administrations of cellular vaccines, preceded by anti-IL-10R antibody treatment. The chemoimmunotherapy additionally included a single administration of the HES-MTX nanoconjugate. The effectiveness of both therapies was evaluated through tumor growth inhibition measurements and analysis of lymphoid and myeloid cell populations in tumor tissues. Additionally, subpopulations of restimulated splenocytes were analyzed, and the production levels of interferon gamma (IFN-γ), IL-10, and IL-4 were evaluated.

Modified dendritic cells, which carry proinflammatory cytokines, were used in immuno- and chemoimmunotherapeutic experiments. The developed therapies effectively inhibited tumor growth, but the rate of tumor growth depended on the type of vaccine used. Incorporating the nanoconjugate prior to immunological treatment primarily reduced the population of suppressor cells. The most effective treatment was observed in two cases: as a result of immunotherapy including the use of a two-component vaccine DC/IL-12/TAg + DC/IL-18/TAg (TGI 62.3%) or after administration of HES-MTX nanoconjugate followed by immunotherapy with three-component vaccine - DC/IL-12/TAg + DC/IL-15/IL-15Rα/TAg + DC/IL-18/TAg (TGI 59.1%).