Abstract 1842: Global proteomics reveals integrin signaling as a driver of infiltration in glioblastoma

Abstract Background: Glioblastoma (GBM), a notably aggressive brain cancer, presents significant treatment challenges due to its propensity for deep, diffuse infiltration into healthy brain tissue. This trait enables GBM to resist and survive following surgery and conventional adjuvant therapies. Emerging evidence suggests that signaling between GBM stem cells (GSCs) may be instrumental in this invasive behavior. Our study aimed to unravel the intricacies of these intercellular communication networks within glioblastoma by employing comprehensive proteomic profiling across a diverse array of patient-derived GSC lines. Methods: We conducted our study using a sex-stratified cohort comprising 17 patient-derived GSC lines. Proteomic profiling encompassed analyses of both GSC lysates and conditioned media under various oxygen conditions (normoxia at 20% O2, hypoxia at 1% and 0.2% O2). Additionally, we incorporated the glioma cerebral organoid (GLICO) system, facilitating co-cultures of GSCs with human cerebral organoids. For in-depth proteomic analysis, we utilized advanced TMT-based liquid chromatography-tandem mass spectrometry (LC-MS/MS; Q-Exactive, Thermo Fisher). Results: Our findings corroborate that GSCs adhere to the tripartite model of proliferation, invasion, and hypoxic response. A salient discovery was the consistent enrichment of integrin signaling pathways in GSCs under hypoxic conditions. Specifically, we observed a significant association between upregulation in integrin signaling (BIOCARTA_INTEGRIN_PATHWAY) and elevated KRAS activity (SWEET_KRAS_TARGETS_UP: r=0.43, p<0.01), as well as hypoxic responses (WINTER_HYPOXIA_UP: r=0.76, p<0.0001) in GSCs. Notably, in the GLICO model, both integrin signaling and KRAS pathways were markedly upregulated in the presence of GSCs compared to cerebral organoids alone (p<0.05). Conclusions: This research highlights the pivotal role of integrin signaling in mediating the invasive attributes of glioblastoma. The data underscore the importance of further exploring key modulators within the integrin signaling pathway, presenting a promising avenue for the discovery of novel therapeutic targets in glioblastoma treatment. Citation Format: Lennart J. van Winden, Rifat Shahriar Sajid, Okty Abbasi Borhani, Evelyn Rose Kamski-Hennekam, Nakita Gopal, Alberto Leon, Phedias Diamandis. Global proteomics reveals integrin signaling as a driver of infiltration in glioblastoma [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 1842.