The role of exosomal CDC6 in the hirudin-mediated suppression of the malignant phenotype of bladder cancer cells.

ABSTRACT

BACKGROUND: Bladder cancer is a malignant tumor characterized by high recurrence and persistence due to the limited therapies that are currently available. Hirudin exerts a strong anticancer effect on several tumors. Thus, it is urgent to explore the biological function of hirudin in bladder cancer and the role of bladder cancer-derived exosomes in tumor inhibition. METHODS: First, a network pharmacology analysis was performed to explore the relationships among hirudin, bladder cancer, and exosomes. Then, the effects of hirudin were examined by CCK-8 assay, flow cytometry, Transwell assay, and tumorigenic ability experiments in vitro. Exosomes derived from cells were identified with transmission electron microscopy, fluorescence labeling, and Western blotting and collected for further microarray analysis. Only CDC6 expression and mRNA abundance in hirudin-treated cells and exosomes was subjected to further validation using quantitative PCR and Western blotting. RESULTS: Through network analysis, we found that hirudin affected bladder cancer, and this effect was related to exosomes. Our studies verified the effects of hirudin by revealing that hirudin inhibits malignant processes of bladder cancer cells in vitro, such as invasion, metastasis, and apoptosis. Similarly, the oncogenic effects of bladder cancer-derived exosomes were successfully isolated and identified. Via microarray assessment of the exosomes, we identified 600 differential mRNAs, of which the expression of the core target CDC6 was found to be significantly different in both The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets. We further confirmed that hirudin suppresses CDC6 expression mRNA abundance in both cells and exosomes. CONCLUSION: Hirudin was able to decrease the expression of CDC6 in bladder cancer cells and exosomes, which effectively repressed the malignant processes of bladder cancer cells.