Tyrosine Kinase Inhibitors Regulate Opg Through Inhibition Of Pdgfr Beta

Nilotinib and imatinib are tyrosine kinase inhibitors (TKIs) used in the treatment of chronic myeloid leukemia (CML) and gastrointestinal stromal tumors (GIST). In vitro, imatinib and nilotinib inhibit osteoclastogenesis, and in patients they reduce levels of bone resorption. One of the mechanisms that might underlie these effects is an increase in the production of osteoprotegerin (OPG). In the current work we report that platelet-derived growth factor receptor beta (PDGFR beta) signaling regulates OPG production in vitro. In addition, we have shown that TKIs have effects on RANKL signaling through inhibition of the PDGFR beta and other target receptors. These findings have implications for our understanding of the mechanisms by which TKIs affect osteoclastogenesis, and the role of PDGFR beta signaling in regulating osteoclastogenesis. Further studies are indicated to confirm the clinical effects of PDGFR beta-inhibitors and to elaborate the intracellular pathways that underpin these effects.