Abstract 1081: Design of combinatory RNA molecules to simultaneously activate tumor immunity and target several signaling pathways in solid tumors

Abstract

Abstract Combination therapy is implicated for many oncological indications to circumvent resistance mechanisms that reduce efficacy of targeted drugs. In recent years, mRNA has been successfully utilized preclinically to deliver cytokines to tumors locally at efficacious doses. Versameb has developed a technology platform which enables combinatorial approaches for intra-tumoral application of nucleotide therapeutics that comprise an mRNA element covalently linked to up to three independent siRNA elements targeting various tumor-relevant genes. Such constructs allow a dose-synchronized treatment of different components in parallel, which opens the opportunity to address up to four cancer targets within a single RNA molecule. For proof of concept, we designed a combinatory molecule consisting of mRNA coding for human interleukin 2 (IL-2) linked to a small interfering RNA (siRNA) targeting vascular endothelial growth factor A (VEGFA). Transfection of A549 adenocarcinoma cells led to dose-dependent secretion of efficacious concentrations of IL-2 and simultaneous complete VEGFA knockdown. IL-2 protein functionality was tested in SK-OV-3 cell spheroids co-cultured with human primary peripheral blood mononuclear cells (PBMCs). After treatment, secreted IL-2 protein induced immune cell activation and consecutive spheroid killing by PBMCs from three independent donors. VEGFA functionality was tested in an in vitro vascularization assay in HUVEC cells. Cells were treated with supernatants of vehicle or RNA transfected SCC-4 head & neck cancer cells producing high endogenous VEGFA, and vascular sprouting was analyzed quantitatively. While vehicle-treated cell supernatant induced vessel sprouting, supernatant from RNA treated cells showed much reduced sprouting in vitro consistent with the lower VEGFA levels measured, confirming functionality of the siRNA effect on VEGFA protein expression. We further provide examples of combinatory molecules targeting up to 4 independent key cancer hallmarks and their functional outcomes in various cancer cell types. In conclusion, mRNA combination constructs can be developed into cancer therapeutics that target several pro-tumorigenic pathways simultaneously with a single molecule overcoming hurdles of delivery, toxicity, and regulatory requirements for combination therapies. Citation Format: Petra Hillmann, Justin A. Selvaraj, Sina E. Zimmerli, Pascale G. Birrer, Claudia C. Bohnert, Klaas P. Zuideveld, Stefan J. Scherer, Friedrich Metzger. Design of combinatory RNA molecules to simultaneously activate tumor immunity and target several signaling pathways in solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1081.