Abstract LB228: DPYSL2 mediates extracellular vesicle-driven reprogramming of the glioblastoma tumor microenvironment

Abstract The purpose of this study was to identify glioblastoma (GBM) proteins that contribute to the hijacking of the tumor microenvironment through extracellular vesicles (EVs). GBM is the most aggressive primary brain tumor in adults. It presents significant challenges due to its universal recurrence and limited survival rates, exacerbated when its located proximal to the lateral ventricles (LV). The cellular subpopulation of brain tumor-initiating cells (BTICs) plays a pivotal role in tumor initiation and invasiveness, interacting with the microenvironment, particularly the cellular components in the subventricular zone (SVZ) in the LV. We employed an integrated multi-omic strategy combining cell-specific proteomics of EV cargo and whole-cell transcriptomics of EV-treated neural progenitor cells (NPCs) to define mechanisms by which BTICs remodel the tumor microenvironment. Using the TurboID cell-specific protein labeling system, we identified a previously unrecognized repertoire of BTIC-derived proteins selectively packaged into EVs. Among these, DPYSL2 (CRMP2) emerged as a prominent EV cargo as it is implicated in cancer cell migration and invasion. Functionally, exposure of human NPCs to BTIC-derived EVs significantly increased NPC proliferation and migratory capacity in vitro, findings that were recapitulated in vivo following intracranial and intranasal delivery of GBM-derived EVs. To define the molecular basis of these phenotypic changes, we performed RNA sequencing of NPCs following EV treatment. Bioinformatic integration, including ontogenic and pathway enrichment analyses, revealed robust activation of oncogenic signaling pathways, notably JAK/STAT, mTOR, and WNT, accompanied by upregulation of downstream effector genes. Importantly, integrative proteomic-transcriptomic analyses identified DPYSL2 as a mechanistic link between EV cargo and NPC transcriptional reprogramming. Prior studies demonstrate that DPYSL2 can interact with JAK kinases, promoting STAT3 activation and transcription of genes such as Vimentin (VIM) and CALCA, consistent with the transcriptomic changes observed in EV-treated NPCs. Overall, we have identified DPYSL2 as a novel regulator of tumor microenvironment hijacking mediated by extracellular vesicles. This multi-omic approach is the first use of cell-specific proteomics to study extracellular vesicles and the first time pairing this method to identify upstream regulators of transcriptomic changes in neural progenitor cells. Collectively, these findings establish a direct molecular connection between BTIC-derived EV proteins and functional reprogramming of neural progenitor cells, providing mechanistic insight into how glioblastoma exploits developmental programs to promote tumor progression. Citation Format: Marissa Russo, Emily Norton, Weiwei Wang, Shreyartha Mukherjee, Daniel Wickland, TuKiet Lam, Hugo Guerrero-Cazares. DPYSL2 mediates extracellular vesicle-driven reprogramming of the glioblastoma tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(8_Suppl):Abstract nr LB228.