[Effect of brucine on metabolism of osteoblasts and osteoclasts in multiple myeloma]

This study was aimed to explore the influence of brucine on the early differentiation of osteoblasts and the metabolic pathway of osteoclast in multiple myeloma (MM) and to compare the effects of brucine and bortezomib on MM. The half inhibitory concentration (IC(50)) of brucine and bortezomib on MM cell line U266 was determined by MTT method; the mRNA levels of alkaline phosphatase (ALP), osteocalcin (OC), osteoprotegerin (OPG) and osteoprotegerin ligand (RANKL) were detected by RT-PCR after the supernatant of cultured U266 cells was added into the culture system for inducing the differentiation of osteoblast line MC3T3-E1 and culturing. The results showed that the IC(50)of bortezomib and brucine on U266 cells for 48 hours were 22.4 nmol/L and 0.16 mg/ml respectively. As compared with osteoblasts treated by supernatant of cultured MM cells alone, the mRNA levels of ALP, OC and OPG in osteoblasts treated by brucine combined with supernatant of cultured MM cells were enhanced (p < 0.05), while the RANKL mRNA level was lowered (p < 0.05), moreover the enhanced and lowered degree also was large (p < 0.05). It is concluded that the influence of brucine on metabolism of osteoblasts and osteoclasts in MM may be realized through the regulation of osteoclasts by osteoblasts. The therapeutic efficacy of brucine on MM is superior to bortezomib.