Abstract:
Objective To illustrate the effect and mechanism of ibrutinib, a Bruton's tyrosine kinase (BTK) inhibitor that inhibits diffuse large B-cell lymphoma (DLBCL) cell survival.
Methods DLBCL cell lines SUDHL-10 and HBL-1 were treated with ibrutinib at different concentrations. A MTT assay was used to detect the inhibition of cell proliferation. Cell apoptosis was analyzed by Annexin V-binding assay, as well as flow cytometry and DAPI staining. The expression of phosphorylated BTK, AKT and ERK was detected by Western blot. DLBCL cells were co-cultured with MSC. The inhibitory effect of ibrutinib on DLBCL cells in tumor microenvironment was assessed in clonogenicity in vitro and in a tumor-bearing non-obese diabetic/severe combined immunodeficient mice in vivo.
Results Up to 2.5 μmol/L and high concentrations of ibrutinib significantly inhibited the proliferation of DLBCL cells in a dose-dependent manner. Approximately 1 and 2.5 μmol/L ibrutinib was added on SUDHL-10 cells for 24 h, and the cell apoptotic rates were (21.73±3.64) % and (34.71±2.36) %, respectively. Both were superior to that of the control group (3.55±1.89) % (P < 0.05). Both two DLBCL cell lines pretreated with 5 and 10 μmol/L ibrutinib for 24 h and exhibited nuclear shrinkage at 5 μmol/L and nuclear fragmentation at 10 μmol/L. The expression of phosphorylated BTK, AKT, and ERK decreased significantly after ibrutinib treatment. Ibrutinib inhibited clonogenicity in vitro (P < 0.01) and cell proliferation and growth in vivo of DLBCL cells in co-culture system. The differences were statistically significant.
Conclusion Ibrutinib can inhibit the proliferation and induce apoptosis of SUDHL-10 and HBL-1 cell lines through a mechanism of blocking the AKT and ERK signaling pathways, as well as the proliferation of DLBCL cells in tumor microenvironment. This finding can significantly benefit DLBCL treatment.
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