MM cell–derived Runx2 upregulates expression of bone-related genes at the mRNA and protein level. (A) Real-time PCR of MMP9, OPN, RANKL, CtsK, and DMP1 expression levels in Runx2 k/d (left panel) and Runx2 k/in 5TGM1 (right panel) cells compared with respective control cells (NT or control). Error bars represent mean ± SEM. *Significant differences with corresponding P value. (B) OPN, RANKL, DMP1, CtsK, and β-actin protein expression in Runx2 k/d and NT control cells (left panel) and in Runx2 k/in and vector control 5TGM1 cells (right panel) were evaluated by western blot.