Effect of PCI-32765 and bortezomib on proliferation and apoptosis of B-cell tumor cell lines and its mechanisms / 中国实验血液学杂志

ABSTRACT

This study was aimed to investigate the effect of Btk inhibitor PCI-32765 and the proteasome inhibitor bortezomib on Raji and Ramos cell proliferation, apoptosis, and its mechanisms. Raji and Ramos cells were treated with PCI-32765 and bortezomib alone and/or their combination. The cell proliferation and apoptosis were detected by CCK-8 and flow cytometry respectively, the expression level of Btk, NFκB, c-IAP1, Bcl-xL and caspase-3 protein were measured by Western blot. The results indicated that (1) after Raji and Ramos cells were treated with PCI-32765 (0.5, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 µmol/L) alone and bortezomib (10, 20, 30, 40, 50, 60, 80 nmol/L) alone and their combination for 48 h, the cell proliferation and vitality were inhibited in a dose-dependent manner and both had synergistic effect; (2) Raji and Ramos cells were treated with PCI-32765 (2.0 µmol/L) and bortezomib (20 nmol/L) alone and their combination for 8, 12, 24, 36, 48 and 72 h, the cell proliferation and vitality were inhibited in a time-dependent manner, the two drugs displayed a synergistic effects; (3) the Raji and Ramos cells were treated with PCI-32765 (2.0 µmol/L) and bortezomib (20 nmol/L) alone and their combination for 48 h, all these treatments could induce significant apoptosis of Raji and Ramos cells.In Raji cell experiment, the cell apoptosis rate in the control group, PCI-32765 group, bortezomib group and PCI-32765 and bortezomib combination group were 10.34 ± 0.53%, 24.26 ± 0.91%, 43.66 ± 1.08% and 74.06 ± 0.72% respectively, and the differences was statistically significant among the different groups (P < 0.05). In Ramos cell experiment, the cell apoptosis rate in the control group, PCI-32765 group, bortezomib group and PCI-32765 and bortezomib combination group are 15.16 ± 1.49%, 71.36 ± 0.82%, 75.32 ± 2.36% and 84.30 ± 0.91% respectively, the differences was statistically significant among the different groups (P < 0.05); (4) PCI-32765 and bortezomib could inhibit the expression level of intracellular Btk, NFκB, Bcl-xl and c-IAP1 proteins, but up-regulate the expression level of caspase-3. It is concluded that PCI-32765 and bortezomib can synergistically inhibit the proliferation and induce apoptosis of Raji and Ramos cells, the mechanism may be associated with inhibition of Btk and NFκB activity, down-regulation of anti-apoptotic proteins expression, such as Bcl-xl and c-IAP1, and increase of caspase-3 expression.