Fucosyltransferase 4-derived Peptide Bioconjugates on Carbon Nanotubes Enhance Antitumor Immunity in an Ovarian Cancer Mouse Model

Background. The interplay between ovarian cancer cells and immune cells within the immunosuppressive tumor microenvironment presents a significant challenge in the development of effective immunotherapies. Therefore, no immunotherapy has yet been approved to treat this disease. This study explored the potential of carbon nanotubes (CNTs) bioconjugated with antigenic epitopes from fucosyltransferase 4 (FUT4) to serve as adjuvants and carriers in ovarian cancer immunotherapy. Results. We confirmed FUT4 overexpression via flow cytometry and confocal microscopy in an immunocompetent ovarian cancer model in which the ID8-Def29/Vegf-a cell line (ID8DVLuc) was inoculated into C57BL6 mice. Mice were immunized with nonconjugated peptide (PEP37), PEP37 bioconjugated CNTs ( f-CNTs ), or f-CNTs plus adjuvant, and nonimmunized mice were used as controls. Tumor development, the spleen, and ascitic fluid immune populations, antibody response, and survival rates were evaluated. The results revealed reduced tumor development and ascitic fluid volume in immunized mice, with the best outcomes in the f-CNT group. Immunized mice presented increased infiltration of leukocytes, M1 macrophages, dendritic cells, T lymphocytes, and CD8+ T cells alongside reduced Tregs. Enhanced IgM, IgG1a, and IgG2a responses were observed in the f-CNT groups. Splenocytes from these groups also showed increased antigen-specific proliferation and enhanced cytotoxicity against ID8DVLuc cells mediated by CD8+ T cells. Survival analysis revealed median survival times of 6, 7.5, 11, and 8.5 weeks for the nonimmunized, PEP37, f-CNT , and f-CNT plus adjuvant groups, respectively. In addition, RNA-seq analysis of f- CNT-immunized mice revealed the overexpression of genes related to antigen processing and presentation, CD8+ T-cell activation, and Th1-type-mediated responses ( H2-K1, H2-D1, B2m, Trex1 Cd80, Cd8a, Prf1, IL18r1, Ccr7, Stat4, Tbx21 ), among others. Conclusion. These findings suggest that f-CNTs enhance the antitumor immune response mediated by M1 macrophage polarization, enhance antigen processing and presentation to CD8+ T cells, and evoke a robust cytotoxic response against ID8DVLuc cells. These findings suggest the potential of this nanocarrier system in ovarian cancer immunotherapy.