Altered expression of ET-1 and HMGB1 together with higher MMP-9 activity in serum-derived exosomes of chronic lymphocytic leukemia.
BACKGROUND Evidences indicate that tumor-derived exosomes released by cancer cells are key mediators of intercellular communication and disease progression in various cancers. This study aimed to investigate the expression of key molecules endothelin-1 (ET-1) and high-mobility group box 1 (HMGB1), as well as the enzymatic activity of matrix metalloproteinase-9 (MMP-9) in serum-derived exosomes from patients with chronic lymphocytic leukemia (CLL). METHODS Serum samples were obtained from twenty-five patients with CLL and twenty-five controls. Exosomes were purified from serum and further characterized through dynamic light scattering (DLS), atomic force microscopy (AFM), and flow cytometry. Real-time PCR was used to determine the mRNA expression of ET-1 and HMGB1 in isolated exosomes. Protein patterns of isolated exosomes were visualized by SDS-PAGE, and then MMP-9 enzymatic activity was assessed using gelatin zymography. RESULTS Isolated exosomes from serum exhibited the expected morphology and marker expression based on characterization data obtained from DLS, AFM, and flow cytometry assays. Real-time PCR results indicated a significant overexpression of ET-1 and HMGB1 in CLL-derived exosomes compared to healthy controls (p < 0.05). In gelatin zymography, the activity of the MMP-9 dimer was significantly higher in patient-derived exosomes than that of controls (p < 0.001). CONCLUSION These findings showed that serum-derived exosomes from CLL patients have higher expression of ET-1 and HMGB1 and higher MMP-9 enzymatic activity. These alterations suggest that exosomal ET-1, HMGB1, and MMP-9 may serve as potential non-invasive biomarkers for disease monitoring and warrant further investigation regarding their biological and clinical significance in CLL.