Abstract:

Objective     To investigate the anti-proliferative and apoptosis effects induced  by  Honokiol (HNK) and bortezomib on KM3 human multiple myeloma cell line in vitro． Methods     Samples were divided into control group and experimental group, and the latter was further subdivided into HNK treatment group (group B, C, D, E, F, G at respective concentrations of 4,6,8,10,12,15μg / mL), bortezomib treatment group (group H, I, J at respective concentration of 5,10,20μg / mL), and combined treatment group (group K,L, M with HNK 4μg/mL + bortezomib 5ng/mL, HNK4μg/mL + bortezomib 10ng / mL and HNK4μg/mL + bortezomib 20ng/mL, respectively). MTT colorimetric assay were performed to assess the cell proliferation, and cell apoptosis were determined by PI and Annexin V fluorescent staining on flow cytometry. Results     Honokiol, at concentrations between 4-15ug/mL, showed significantinhibiting effect on KM3 cell proliferation. At 24h, 48h, and 72h, the inhibition rate rose from 20.38%, 27.45% and 44.94% to 80.54%, 89.99% and 90.91%, respectively. There were significant differences among different groups, or at different time points. The inhibition rates of honokiol on KM3 cells at 48h in H, I, J, K, L, M were 3.13%, 36.22%, 53.99%, 52.68%, 69.99%, 78.53%, respectively. There were considerable differences between K and H, L and I, or M and J (P<0. 05). Apoptosis rate of KM3 cells in B, C,  E at 24h and 48h were 6.92%、16.15%、60.70% and 18.84%、37.21%、86.07%, respectively. There were significant differences in apoptosis among different groups at the same time point(P<0. 05). Apoptosis rate of KM3 cells in H and I group were 9.27% and 17.87% at 24h, 11.92% and 53.51% at 48h. Statistical differences were found in apoptosis between H and I group (P<0. 05). Apoptosis rates of KM3 cells in K and L group were 15.75% and 22.18% at 24h,  35.96% and 74.70% at 48h. The apoptosis rates in K and L group were significantly higher than H and I group (P<0. 05). Conclusion      Honokiol and bortezomib can inhibit the proliferation of KM3 cells and induce cell apoptosis,  moreover,  the combination of honokiol and bortezomib can increase the apoptosis rates and enhance cytotoxic activity of KM3 cells. 

Key words: Honokiol； bortezomib;  KM3 cell line;  Growth inhibition; Apoptosis