Abstract 7309: Investigating IL-1β signaling axis and inhibition strategies with small molecules in canine metastatic osteosarcoma: Insights for translational medicine

Abstract Introduction: Osteosarcoma (OS) is the most common bone tumor in pet dogs and people. While localized therapies, including surgery and ionizing radiation, effectively control bone-related events, options for slowing metastatic progression remain limited and only marginally active. Advances in drug delivery highlight the need for predictive animal tumor models to accelerate therapeutic development for humans. The clinical features, behavior, histopathology, treatment response, and genetics of OS in dogs closely mirror those in humans, making dogs an ideal comparative model. Dogs with spontaneous OS offer valuable insights into OS biology and are particularly useful for evaluating immunotherapeutic strategies. The pro-inflammatory effects of interleukin-1-beta (IL-1β) in the tumor microenvironment may hinder immunological responses against OS in both species. IL-1β is upregulated in the myeloid compartment of canine OS patients and facilitates metastatic progression in other cancers, including breast cancer. This study investigates the biological sources and role of IL-1β in OS metastatic biology and potential blocking strategies with small molecule inhibitors, offering insights for translational medicine. Methods: Canine OS cells, primary monocytes, monocyte-derived macrophages, and DH82 cells were used to investigate IL-1β secretion and receptor expression. Immunological and proliferative factors under IL-1β exposure were assessed by ELISA and clonogenic assays. RNA NanoString profiling was employed to characterize gene transcripts in both healthy canine lungs and metastatic OS lesions. A high-throughput screening approach evaluated the ability of 80, 000 small molecules to inhibit IL-1β intracellular downstream signaling and to inhibit IL-1β biological release and inflammasome activity. Results: Canine OS cells express receptors related to IL-1β signaling and secrete pro-metastatic factors upon IL-1β exposure. However, OS cells do not secrete IL-1β. Primary monocytes and DH82 cells secrete IL-1β in response to inflammasome and caspase activator molecules. Monocyte-derived M1 macrophages were found to release significantly higher amounts of IL-1β compared to M0 and M2 macrophages. Metastatic lesions in canine OS exhibited distinct gene transcript profiles. Small molecules and structure-related molecules with potent IL-1β inhibition activities were identified. Conclusions: Our study showed that IL-1β is secreted by monocytes and macrophages, not by OS cells. IL-1β induces the release of pro-metastatic factors by canine OS cells, suggesting its role in OS metastasis. Targeted inhibition of IL-1β may be a potential therapeutic strategy for controlling metastatic progression in OS and collectively underscore the potential value of comparative oncology approach towards successful translation medicine. Citation Format: Matheus Moreno Passos Barbosa, Vishnu V. Krishnamurthy, Timothy M. Fan. Investigating IL-1β signaling axis and inhibition strategies with small molecules in canine metastatic osteosarcoma: Insights for translational medicine [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 7309.