Abstract P48: Oral Delivery of Bioorthogonal Catalytic Centres for Treating Gastric Cancer Using Gastrointestinal Tract Stabilized Thermostable Exoshells

Abstract Gastric cancer (GC) is the 5th most prevalent cancer worldwide. Current treatment methods are extremely challenging due to a variety of factors. Hence, targeted oral therapies that enable maximal drug release and absorption, while limiting potential systemic side effects are being explored. To materialize this, we introduce an oral disulfide-linked thermostable exoshell (DS-tES) system that delivers protein-based bioorthogonal catalytic centres directly to cancer tissues. DS-tES was effective at encapsulating and stabilizing labile catalytic centres such as horseradish peroxidase (HRP), preventing degradation in the harsh gastric environment. The enzymatic catalysis of the prodrug indole-3-acetic acid (IAA) produced active metabolites such as indole-3-carboxaldehyde in the presence of DS-tES encapsulated catalytic centres. In this study, we investigated the anti-cancer properties of DS-tES encapsulated HRP in combination with IAA. In vitro cell studies revealed dose and time dependent inhibition of gastric cancer cell growth, which was reversed in the presence of necrostatin-1 (nec-1), a RIPK1 inhibitor. The combination of DS-tES-HRP-IAA (DHI) elicited a time dependent induction of necroptosis. qPCR analysis revealed that DHI treatment upregulated necroptosis marker genes such as RIPK1, RIPK3 and MLKL. Furthermore, DHI treatment increased the mitochondrial membrane permeability transition and reactive oxygen species production. In an N-Methyl-N-Nitrosourea (MNU) induced gastric cancer mice model, oral administration of DHI significantly suppressed MNU induced tumor polyp growth in the stomach without any reduction in the mice body weight. Mass spectrometry-based quantifications revealed microgram amounts of the active metabolite in plasma from mice treated with DHI compared to control groups. In conclusion, we demonstrate that DHI is a unique inducer of necroptosis that inhibits tumor growth in vitro and in vivo. Citation Format: Muthu Kumaraswamy Shanmugam, Girish Vallerinteavide Mavelli, Pang Yuze, Lik Hang Wu, Hrucha Shielesh Damle, Lim Poh Leong, Pakkiri Leroy Sivappiragasam, and Chester Lee Drum. Oral Delivery of Bioorthogonal Catalytic Centres for Treating Gastric Cancer Using Gastrointestinal Tract Stabilized Thermostable Exoshells [abstract]. In: Proceedings of Frontiers in Cancer Science 2024; 2024 Nov 13-15; Singapore. Philadelphia (PA): AACR; Cancer Res 2025;85(15_Suppl):Abstract nr P48.