Session: MP14: Bladder Cancer: Basic Research & Pathophysiology I
MP14-06: E-liquid Exposure Induces the Release of Pro-Oncogenic Extracellular Vesicles from Bladder Cancer Cells that Promote the Malignant Transformation of Recipient Urothelial Cells
Introduction: Cigarette smoking is the best-established risk factor for bladder cancer (BC). While E-cigarette usage has risen rapidly in recent years and preclinical and clinical evidence suggests that exposed tissues may be subject to genotoxic, inflammatory, and oxidative stress, the potential oncogenic risks associated with vaping are not fully understood. Our lab has previously demonstrated that BC cell-derived extracellular vesicles (BCEVs) can promote the neoplastic transformation of recipient urothelial cells. This study was designed to explore the impact of smoking or E-cigarette use on the pro-oncogenic properties of BCEVs. Methods: Human grade IV BC TCCSUP cells were exposed to cigarette smoke extract (CSE), unflavored E-liquid (UEL), or menthol-flavored E-liquid (MEL), and BCEV release was measured via nanoparticle tracking assay. BCEV-induced genotoxic damage, oxidative stress, inflammation, and apoptotic responses in recipient SV-HUC urothelial cells were quantified by ?H2Ax staining, ELISAs, reactive oxygen species (ROS) assays, and flow cytometry. Protein cargos in these BCEVs were quantified by label-free quantitative LC-MS. SV-HUC cells were treated with these BCEVs for 12 weeks, after which a soft agar colony forming assay was used to assess their neoplastic transformation. Results: CSE, UEL, and MEL treatment significantly increased rates of BCEV release. CSE- and MEL-BCEVs enhanced NF-?B activation, DNA double-strand break (DSB) formation, and ROS production in recipient SV-HUC cells. Proteomic analyses indicated that these CSE- and MEL-BCEVs contain high levels of known BC-related pro-oncogenic proteins including PGAM1 and VCP, as well as the dimeric DSB repair enzymes XRCC5/6. Notably, long-term MEL-BCEV treatment induced significantly higher rates of neoplastic urothelial cell transformation. Conclusions: CSE or MEL exposure significantly alter the number and composition of EVs released from BC cells. These BCEVs, in turn, can induce genotoxic, inflammatory, and oxidative stress in recipient urothelial cells, with MEL-BCEVs ultimately promoting urothelial cell transformation. These data highlight the important role that BCEVs may play as mediators of BC onset or recurrence, with the use of certain E-cigarettes potentially compounding this risk. SOURCE OF Funding: This work is supported by the Department of Defense W81XWH-19-1-0198.
