Abstract 458: Nanoparticle-mediated delivery of miR-590-3p decreases recurrent GBM tumor growth by inhibits multiple oncogenic nodes

Abstract Glioblastoma (GBM) is the most lethal and aggressive form of brain cancer. Despite aggressive therapy consisting of surgery followed by radio/chemotherapy GBM recurs in almost all patients and, currently, there are no proven therapies to treat recurrent GBM (rGBM). Recent developments in nanomedicine provide new and promising opportunities to develop new targeted therapeutics to treat brain tumors. We have recently developed PBAE nanoparticle formulations optimized for in vivo miRNA delivery to brain tumor stem cells, or GSCs. Carefully selecting one miRNA to target several mRNAs dysregulated within a pathway can allow the targeting of multiple nodes using a single agent, mimicking combinatorial therapies. To test this hypothesis, we performed bioinformatic analysis of RNA sequencing from GSCs and clinical rGBM specimens combined with gene set enrichment analysis (GSEA) and identified TGFBR2 signaling as a targetable pathway in rGBM. We show that SMAD2 signaling, a downstream effector of TGFBR2, is enriched in rGBM and that patients with elevated TGFBR2 transcripts respond poorly to current standard of care. Utilizing patient-derived xenograft lines from rGBM, we show that blocking TGFBR2 signaling using siRNAs or ITD1, a selective TGFBR2 inhibitor, decreases the stem cell capacity, cell viability and re-sensitizes clinical rGBM cells to temozolomide (TMZ) in-vitro. In vivo, we show that ITD1 is modestly effective in subcutaneous and ineffective in orthotopic rGBM models. Not surprisingly, these tumors exhibited classical growth patterns associated with acquisition of resistance. To overcome this obstacle, we performed a miRNA-based network analysis in rGBM and identified miR-590-3p as a putative tumor suppressor that targets SMAD2 signaling at multiple nodes in rGBM. In-vitro, transgenic miR-590-3p robustly decreased the expression of 37 putative oncogenes simultaneously concurrent with decreasing stem cell capacity, cell viability and re-sensitizing rGBM PDX cells to TMZ. In vivo delivery of miR-590-3p to established PDX-derived rGBM orthotopic tumors using novel PBAE nanocarriers robustly decreased tumor sizes and increased tumor necrosis. These results show that the promiscuous nature of miRNAs, in combination with cutting-edge nucleic acid delivery vehicles, can be leveraged as advanced targeted therapeutics for rGBM bypasses the resistance that is developed to standard of care and available small molecules. Citation Format: Hernando Lopez-Bertoni, Sophie Sall, Harmon Khela, Jack Korleski, Katherine Luly, Maya Johnson, Bachchu Lal, Amanda Johnson, Stephany Tzeng, Jordan Green, John Laterra. Nanoparticle-mediated delivery of miR-590-3p decreases recurrent GBM tumor growth by inhibits multiple oncogenic nodes [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 458.