a Representative TRAP staining images of RAW264.7 cells treated with or without ibrutinib, acalabrutinib or SOMCL-17-016 (1000 nM) and then stimulated with RANKL/M-CSF for 4 days. b The number of TRAP-positive multinucleated osteoclasts (≥3 nuclei) was quantified. c The MTT assay was performed to analyze the viability of RAW264.7 cells treated with the indicated concentrations of ibrutinib, acalabrutinib or SOMCL-17-016 for 4 days. d mRNA levels of the osteoclast marker genes NFATc1, TRAP, TRAF6, c-Fos and c-Jun. e, f Western blot analysis of the indicated proteins in the RANKL signaling pathway. The data are shown as the means ± SEMs; *P < 0.05, **P < 0.01 and ***P < 0.001, significantly different from cells stimulated with RANKL/M-CSF only.