Abstract

Macrophage inflammatory protein 1 alpha (MIP-1 alpha) is detected at high concentrations in patients with multiple myeloma, and it is thought to play an important role in the etiology of multiple myeloma and osteolysis. Thus, we investigated whether or not YM529/ONO-5920, a new bisphosphonate, inhibited MIP-1 alpha mRNA expression in, and MIP-1 alpha secretion from, mouse myeloma cells. When the cells were stimulated by lipopolysaccharide, increased MIP-1 alpha mRNA expression and MIP-1 alpha secretion were observed. YM529/ONO-5920 inhibited MIP-1 alpha mRNA expression and MIP-1 alpha secretion in a concentration-dependent manner. A transient increase in the phosphorylation of extracellular-regulated kinase 1/2 (ERK1/2) and Akt was observed after lipopolysaccharide stimulation. After YM529/ONO-5920 was given, there was no transient increase in the phosphorylation of ERK1/2 or Akt. These results indicated that YM529/ONO-5920 inhibited the expression and secretion of MIP-1 alpha through blocking the signaling pathway of the Ras/mitogen-activated protein kinase kinase/ERK and Ras/phosphatidylinositol-3 kinase/Akt. Accordingly, YM529/ONO-5920 appears to have promise for use in effective future therapy for osteolysis and myeloma cell growth that depends on MIP-1 alpha.