Dual facets of MSC-derived small EVs: regulatory insights into antitumor mechanisms in pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a dense, fibrotic, immunosuppressive, and desmoplastic extracellular matrix. Mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) have emerged as a novel therapeutic strategy. Nonetheless, the potential dual effects of MSC-EVs on tumor cells warrant careful consideration. This study aimed to evaluate the mechanistic effects of MSC-EVs on PDAC. Wharton's Jelly (WJ) MSC-derived small EVs were isolated using ultracentrifugation method and analyzed through nanoparticle tracking analysis (NTA) and flow cytometry. EVs were added to Panc-1 cells at concentrations of 4000-10,000 EVs per cell, and a preliminary MTT assay was performed. In subsequent experiments, EVs were added to Panc-1 cells at concentrations of only 4000, 8000 and 12,000 EVs per cell. After 24 h, apoptosis and cell cycle analyses were performed. The expression of epithelial-mesenchymal transition (EMT)-related and immune-related genes was analyzed. Cell cycle analysis showed higher G1 phase percentage in the control group (31%) compared to MSC EV-treated groups (35-36%). Apoptosis analysis revealed similar viable and necrotic cell percentages among the control (80% viable) and treated groups (approximately 78-79% viable). The CD44, VIM, MMP9, TIMP1, and ZEB1 genes were downregulated in treated groups compared to the control. Although CLDN1 and CDH1 genes were upregulated at the lowest EV concentration, they were downregulated at higher EV concentrations. Immune gene analysis showed downregulation of pro-inflammatory cytokines (IL-6, TNF-α, IFN-γ, IL-1α, IL-1β) and upregulation of the anti-inflammatory cytokine IL-10 in treated groups. This study revealed the dual role of WJ-MSC small EVs in PDAC. While they suppressed cell proliferation and modulated EMT markers, indicating their antitumor potential, they also exhibited an immunosuppressive profile. These findings highlight both the promise and challenges of using WJ-MSC small EVs as therapeutic agents, necessitating further studies to optimize their application and balance their effects.