(A) Radiograph images of the injected femur on day 13. Breast cancer-induced bone remodeling is reduced in mice that received systemic administration of SB203580 (15 and 30 mg/kg, i.p., 2× daily, 7 days). Fractures as indicated by arrows were defined as full-thickness cortical loss. (B) Bone remodeling ratings of all treatment groups show that the breast cancer-induced bone remodeling is observed 7 days following the surgery, with no difference between drug- and vehicle-treated mice. Breast cancer-treated mice receiving SB203580 (15 and 30 mg/kg, i.p. 2× daily, 7 days) demonstrated reduced bone destruction on day 13 compared with breast cancer-treated mice that received saline. (C) Treatment with SB203580 reduced the percentage of mice with breast cancer-induced spontaneous fractures compared to vehicle-treated animals. n = 6-8.