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Abstract PR16: RNA aptamers specific for tumor-infiltrating myeloid cells

Myeloid cells have been extensively studied in the tumor microenvironment for their role in promoting cancer cell survival and metastases. However, their peculiar activated phenotype has not been exploited for the targeted delivery of anticancer agents to the tumor site. Here we report a new therapeutic strategy that allows the delivery of cancer drugs to both tumor and metastases by the preferential targeting of genetically stable tumor-infiltrating myeloid cells (TIMC). We identified 4 monoclonal RNA aptamers that specifically recognize myeloid-derived suppressor cells (MDSC) and macrophages infiltrating the tumor, but not the splenic counterparts. The use of these aptamers conjugated to doxorubicin greatly enhances the accumulation of the chemotherapeutic drug in the primary and metastatic tumor sites in multiple cancer models. Compared to their individual components or current therapeutic approaches, doxorubicin-conjugated TIMC-specific aptamers show enhanced anticancer efficacy and no detectable treatment-related toxicity. This strategy has the intrinsic potential to target multiple tumor types through the same reagents. This abstract is also being presented as Poster A35. Citation Format: Adriana De La Fuente, Jimmy Caroli, Dimitri Van Simaeys, Serena Zilio, Emilia Mazza, Vincenzo Bronte, Silvio Bicciato, Paolo Serafini. RNA aptamers specific for tumor-infiltrating myeloid cells [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr PR16.