Abstract 476: <i>In vivo</i> CD47-mediated targeted oligonucleotide delivery for endolysosomal escape in cancer treatment

Abstract Therapeutic oligonucleotides, such as small interfering RNAs (siRNAs) and antisense oligonucleotides (ASOs), hold promise for suppressing pathogenic genes, including mutated KRAS, a key driver in many cancers. However, their systemic administration is challenged by rapid degradation and poor cellular uptake. Existing delivery systems, like lipid nanoparticles, face limitations in safety, extrahepatic delivery, and evading endolysosomal degradation. To address these limitations, we developed and evaluated an extracellular vesicle (EV)-based delivery platform for CD47-mediated oligonucleotide delivery in vivo. EVs, known for their biocompatibility, were engineered to display the SIRPα membrane protein on their surface, creating CD47-targeting SIRPα-EVs (S-EVs). These S-EVs were designed to preferentially accumulate in CD47-overexpressing pathological tissues, such as inflamed and tumor sites, as confirmed by in vivo imaging systems, flow cytometry, and intravital live imaging. To ensure consistent oligonucleotide encapsulation and batch-to-batch stability, we employed a cholesterol-based exogenous loading technique. Mechanistically, S-EVs entered target cells through CD47-mediated endocytosis, bypassing endolysosomal degradation and delivering oligonucleotides efficiently. Our results demonstrated that S-EVs accumulated selectively in CD47 overexpressing tissues and delivered oligonucleotides more efficiently than lipid-based transfection reagents or naïve EVs, significantly enhancing therapeutic efficacy. When administered systemically in an LPS-induced inflammatory model, S-EVs loaded with NLRP3-ASOs effectively reduced inflammation, outperforming naïve EVs. In a KRAS-mutated tumor model, KRAS siRNA-loaded S-EVs (siKRAS-S-EVs) suppressed KRAS expression in tumor tissues and increased CD8+ T cell infiltration into the tumor microenvironment, demonstrating significant antitumor effects. When combined with PD-1 blockade therapy, siKRAS-S-EVs led to substantial survival improvements, with 60% of treated animals achieving complete tumor remission. These findings emphasize the advantages of CD47-mediated EV delivery, enabling selective targeting of pathological tissues and efficient intracellular delivery of therapeutic oligonucleotides by bypassing endolysosomal degradation. This study highlights the potential of EV-based CD47-mediated delivery platforms as next-generation systems for treating cancers and other CD47-overexpressing diseases, addressing the limitations of current therapeutic approaches. Citation Format: Min Kyoung Jo, Yewon Jeong, Yoon Kyoung Kim, Seok Ho Song, Hyemin Joo, Yoonjeong Choi, Inkyu Lee, Minjeong Kwon, Gi Beom Kim, In-San Kim, Gi-Hoon Nam. In vivo CD47-mediated targeted oligonucleotide delivery for endolysosomal escape in cancer treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 476.