[Berberine induces apoptosis in chronic lymphocytic leukemia B cells by targeting Lyn and inhibiting the BCR pathway]

Objective To investigate the role of berberine (BBR) in chronic lymphocytic leukemia (CLL) and to determine whether it exerts anti-tumor effects by directly targeting and inhibiting Lck/Yes tyrosine kinase (Lyn), a novel Src family kinase, thereby inducing leukemia cell apoptosis. Methods Molecular docking was employed to predict the binding potential between BBR and Lyn kinase, and biotin pull-down assay was conducted to validate their direct interaction. In vitro experiments utilized the human chronic B-cell leukemia cell line MEC-1, with cell viability and apoptosis assessed via CCK-8 and TUNEL staining, respectively. Key proteins in the B-cell receptor (BCR) pathway, including Lyn, spleen tyrosine kinase (Syk), phosphatidylinositol 3-kinase (PI3K), protein kinase B (AKT), and apoptosis-related markers Bcl2-associated X protein (BAX), Bcl2-associated agonist of cell death (BAD), cleaved caspase-3(c-caspase-3), and B-cell lymphoma 2 (Bcl2), were analyzed by Western blot. Transcriptional levels of downstream genes, including cyclin D1 (Cyclin D1), Bcl2, and myelocytomatosis viral oncogene homolog (c-Myc), were quantified using real-time quantitative PCR. Functional rescue experiments were performed using Lyn-overexpressing lentiviral stable cell lines. In vivo, a C-NKG mouse leukemia model was established via tail vein injection, with tumor infiltration in the spleen, liver, and lungs evaluated by HE staining, and therapeutic effect of BBR assessed by survival analysis. Results In vitro, BBR inhibited MEC-1 cell proliferation in a concentration-dependent manner and induced apoptosis, while suppressing the phosphorylation of BCR pathway proteins and downstream gene expression. Molecular docking and pull-down assays confirmed the direct binding between BBR and Lyn. The overexpression of Lyn reversed BBR-induced apoptosis and pathway inhibition. In vivo, BBR treatment significantly reduced organ infiltration and prolonged survival in leukemic mice, which can be reversed by Lyn overexpression. Conclusion BBR induces CLL cell apoptosis and inhibits tumor progression in vitro and in vivo by directly targeting Lyn kinase and suppressing the BCR-Lyn-PI3K-AKT signaling pathway. These findings provide experimental evidences supporting BBR as a natural Lyn-targeted therapeutic agent for CLL.