Abstract 6586: Targeting cancer cell dynamin activity <i>in vitro</i> impacts exosome production and cell proliferation

Abstract Introduction: These experiments aimed to determine the effects of dynamin (DNM) on the exosome production of cancer cells. Researchers can easily collect exosomes, which are circulating extracellular vesicles, from the blood and analyze biological processes from the tumors of origin. This is particularly advantageous in solid tumors with limited tissue available for study. Methods: Pancreas cancer and glioblastoma cells were grown until confluent, then seeded at equal density with 75 uM dynasore (DNSR), 30 uM Bis-T-23, or control (DMSO) for 24, 48, 72, and 96 hours (h). At the specified time, media was gathered for exosome precipitation, and cells were counted with trypan blue exclusion for proliferation. Exosomes were precipitated by SBI exosome tc precipitation solution, protein yield was measured by nanodrop, and the # of CD63 exosomes was determined using SBI’s CD63 ELISA kit. Additionally, the exosomes were fixed on silicon chips for SEM and imaged using the JEOLJEM-ARM200CF. All statistical analysis was done using a t-test: Paired Two Sample for Means. Results: DNM inhibition had a more significant effect on cell proliferation and exosome precipitation than DNM oligomerization. AsPC cells treated with DNSR had a significant decrease in proliferation compared to DMSO at 72h (1.0 x 105 cells + 3.536 x 104 vs 7.125 x 105 cells + 7.181 x 104, respectively, p=0.005) and 96h (2.125 x 105 cells + 5.154 x 104 vs 6.625 x 105 cells + 7.181 x 104, respectively, p=0.025). U87 (1.5 x 105 cells + 3.536 x 104 vs 4.875 x 105 cells + 8.985 x 104, respectively, p=0.02) cells had decreased proliferation after 96h compared to DMSO. AsPC cells also had a significant increase in proliferation after 96h in response to Bis-T-23 compared to DMSO (1.125 x 106 cells + 1.561 x 105 vs 6.625 x 105 cells + 7.181 x 104, p=0.024). Exosome concentrations were measured in the supernatant and normalized to cell concentrations, AsPC had a significant difference in exosomes per cell in response to DNSR at 72h (25.8 ng/cell + 7.0 vs 2.6 ng/cell + 0.2, respectively, p=0.013) and 96h (10.3 ng/cell + 2.8 vs 2.6 ng/cell + 0.2, respectively, p=0.039), and to Bis-T-23 at 96h (1.7 ng/cell + 0.2 vs 3.1 ng/cell + 0.4, respectively, p=0.013). U87 (14.6 ng/cell + 5.8 vs 3.4 ng/cell + 0.5, respectively, p=0.002) had a significant change in exosomes precipitated per cell at 96h after dynamin inhibition. Conclusions: Data show extracellular vesicles, specifically exosomes, have been implicated as data transfer units between cells. To be an exosome, a membrane vesicle needs to be 30-90 nm and of endocytic origin enriched with tetraspanin molecules. Here, we demonstrate the impact of targeting DNM activity on the cells’ ability to proliferate and the quantity of exosomes produced over time. Exosomes have implications in both tumor suppression and proliferation. Our data shows that targeting DNM and exosomes could aid in the effectiveness of diagnosis or treatment of cancer. Citation Format: Alexander J. Willis, Indira Kondapally, Narjess Hajilou, Paul Grippo, Tolou Shokuhfar, Herbert H. Engelhard, Yolande Chen. Targeting cancer cell dynamin activity in vitro impacts exosome production and cell proliferation [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 6586.