[Effects of Bortezomib Combined with Polyphyllin Ⅶ on Proliferation, Apoptosis and Oxidative Stress of Myeloma Cells].

Objective: To investigate the effects of bortezomib (BTZ) combined with polyphyllin Ⅶ (PP7) on proliferation, apoptosis and oxidative stress of myeloma cell line ARH-77.

Methods: MTT assay was used to detect the inhibitory effects of different concentrations of BTZ, PP7 monotherapy, and their combination on the proliferation of ARH-77 cells. In subsequent experiments, the cells were divided into 4 groups: control group (no drug added), BTZ (15 nmol/L) group, PP7 (1.5 μmol/L) group and BTZ(15 nmol/L)+PP7 (1.5 μmol/L) group. The effects of the two drugs on the morphology of ARH-77 cells were observed. Flow cytometry was used to detect the apoptosis rate of the cells in each group. Calcein-AM/PI double staining kit was used to observe the status of the cells and the cell viability were evaluated. The expression of apoptosis-related proteins were detected by Western blot. DCFH-DA fluorescent probe was used to detect the levels of reactive oxygen species (ROS).

Results: Both BTZ and PP7 monotherapy, as well as their combination, could inhibit the growth of ARH-77 cells in a dose-dependent manner (r=-0.9717, r=-0.9941, r=-0.9951), and the combination of BTZ and PP7 exhibited a synergistic effect within a certain concentration range. Compared with the BTZ group and PP7 group, the apoptosis rate of the BTZ+PP7 group was significantly increased ( < 0.01), the expressions of pro-apoptotic proteins Bax, Smac and P53 were significantly upregulated ( < 0.05), the expression of anti-apoptotic protein Bcl-2 was significantly downregulated ( < 0.01), and the ratio of Bax/Bcl-2 was significantly increased ( < 0.01). Compared with the control group, the level of ROS in the BTZ, PP7 monotherapy group and BTZ+PP7 group were significantly increased ( < 0.05).

Conclusion: BTZ combined with PP7 can inhibit the proliferation and induce apoptosis of ARH-77 cells, and increase the level of intracellular ROS.