Berberine suppresses bladder cancer cell proliferation by inhibiting JAK1-STAT3 signaling via upregulation of miR-17-5p

Background: Berberine (BBR), an active component extracted from Coptis chinensis, has shown anti-tumor effects in multiple tumors. However, the underlying mechanisms haven’t been fully elucidated. In this study, the effects of BBR on bladder cancer (BCa) cells and the underlying mechanisms were investigated both in vivo and vitro. Methods: MTT, colony formation, EdU incorporation assays and xenograft tumor models were performed to evaluate the anti-proliferation effects of BBR on BCa cells in vivo and vitro. The roles of BRR in migration and invasion of BCa cells were investigated by wound-healing, transwell migration and invasion assays. The apoptosis and senescence induced by BBR were determined by flow cytometry, tunel assay and senescence-associated β-galactosidase (SA-β-gal) activity assay. Potential candidate targets were screened using western blot. The relationships between miR-17-5p and JAK1-STAT3 pathway were then predicted using in-silico analysis and identified by dual-luciferase reporter assay. The regulatory mechanism of miR-17-5p mediated suppression of JAK1-STAT3 pathway caused by BBR treatment was validated by qRT-PCR and western blot.Results: We found that BBR showed significant cytotoxic effects against bladder cancer (BCa) cell lines both in vivo and vitro, with much lower cytotoxic effects on human normal urothelial cell line SV-HUC-1. BBR treatment induced DNA replication defects and cycle cell arrest, resulting in apoptosis or cell senescence, depending on p53 status, in BCa cells. Mechanically, BBR exerted anti-tumor effects on BCa cells through inhibiting JAK1-STAT3 signaling via promoting expression of miR-17-5p, which directly bound to 3’ UTR of JAK1 and STAT3 and downregulated their expressions. Conclusion: Our results demonstrate that BBR exerts anti-tumor effects through perturbing JAK1-STAT3 signaling via upregulating expression of miR-17-5p in BCa cells, and BBR may serve as a potential therapeutic option for BCa treatment.