Abstract 1189: MYB-driven extracellular vesicle-associated microRNAs in pancreatic cancer: potential significance in pathobiology and biomarker development

Abstract The oncogenic transcription factor MYB is aberrantly expressed in pancreatic cancer (PC), where it plays a key role in tumor progression and metastasis. Our previous studies have demonstrated that MYB supports hypoxic survival through metabolic reprogramming and modulates the cellular secretome, highlighting its potential role in shaping the pancreatic tumor microenvironment (TME). Extracellular vesicles (EV), secreted by nearly all cell types, carry a wide range of biological molecules and serve as crucial mediators of intercellular communication. microRNAs (miRNAs) are among the most abundant EV cargo components, regulating a variety of gene targets through post-transcriptional mechanisms. In this study, we investigated the impact of MYB on EV shedding and EV encapsulated miRNA cargo. EV were isolated from the conditioned media (CM) of endogenous MYB-overexpressing non-targeting sgRNA-transfected control cells (MYBCtrl) and MYB knockout (MYBKO) cells by differential-speed centrifugation and subjected to nanoparticle tracking analysis (NTA), RNA isolation, and next-generation small RNA sequencing (sRNA-seq). NTA revealed that MYBKO cells released a higher number of large EV (LEV) and a reduced number of small EV (SEV) compared to the MYBCtrl PC cells, while no significant differences in medium-sized EV (MEV) were observed. Through sRNA-seq, we identified differential levels of 215 miRNAs in SEV, with 99 miRNAs exhibiting lower and 116 higher levels in MYBKO cells relative to MYBCtrl cells. Gene ontology (GO) and KEGG pathway enrichment analyses of the target genes associated with these differentially-present miRNAs revealed their involvement in various biological processes, including small GTPase-mediated signal transduction, cellular growth, apoptosis, histone modification, axon guidance, immune suppression, and extracellular matrix degradation. Together, these findings suggest a novel role for MYB in stromal remodeling by regulating EV release and biogenesis, as well as influencing the miRNA content of EV in PC cells. This insight could pave the way for the development of targeted therapeutic interventions and novel diagnostic and prognostic biomarkers for pancreatic cancer. Citation Format: Shashi Anand, Kunwar Somesh Vikramdeo, Mohammad Aslam Khan, Seema Singh, Moh'd Khushman, Ajay Pratap Singh. MYB-driven extracellular vesicle-associated microRNAs in pancreatic cancer: potential significance in pathobiology and biomarker development [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 1189.