Abstract 6061: Development of target cell-penetrating scFv conjugate degrader for the selective inhibition of mutant, resistant KRAS cancer

Abstract The activation of mutations in the RAS gene, which is frequently observed in human cancers, induces downstream critical effectors, contributing to tumorigenesis. While attempts to directly target the GTP-bound, activated RAS have shown some success in certain cancer treatments, resistance remains a challenge. Our objective is to develop a cell-penetrating single-chain fragment variable (scFv) degrader that targets mutant KRAS for degradation. The scFv, binding specifically to antigens, can mitigate the side effects of non-specific binding seen with chemical drugs. However, due to the limited cell-penetrating capability of scFv, a delivery carrier is often necessary. In this study, a cancer targeting, and cell-penetrating synthetic peptide (CPP) was developed as a drug delivery carrier and added to the sequence of scFv. To this conjugate, a von Hippel-Lindau (VHL) expressing sequence was added to enable the scFv binding to mutant KRAS, enabling its proteasomal degradation. These conjugates were engineered as a plasmid DNA to be expressed as a protein conjugate in CHO cells. The purity of the scFv-VHL-CPP degrader was confirmed by SDS PAGE. In SPR results, the degrader not only exhibited high binding ability to mutant KRAS but also influenced the proliferation of KRAS mutant cells in cell viability tests. Mutant GTP-bound KRAS was reduced by the KRAS degrader in KRAS mutant cancer cells. The in vivo study further confirmed the degradation of the KRAS, as reflected by the significantly reduced tumor growth. In conclusion, a degrader protein binding to mutant KRAS that consists of cell penetrating peptide, scFv, and VHL is expected to become a new protein anticancer drug especially effective against mutant, resistant KRAS-mediated cancer cells. Especially, the design of the target cell penetrating peptide-scFv-VHL would be served as a platform for the target protein degrader development. Citation Format: Gookjin Yoon, Beom Soo Jo, Dong Woo Lee, Jinwook Yang, Min-Ho Park, Sanghui Seok, Jue Yeon Lee, Chong Pyoung Chung, Yoon Jeong Park. Development of target cell-penetrating scFv conjugate degrader for the selective inhibition of mutant, resistant KRAS cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6061.