Inhibition of bone metastasis from breast carcinoma by rosmarinic acid.

Skeletal disorders are a common complication of breast cancer and will be found in the vast majority of women with metastatic disease. Our study showed that rosmarinic acid (RA) could inhibit the migration of MDA-MB-231BO human bone-homing breast cancer cells dose-dependently. Furthermore, in ST-2 murine bone marrow stromal cells cultured with RA there was a significant and dose-dependent increase in alkaline phosphatase (ALP) activity, with the number and size of mineralized nodules increasing. According to Western blot and quantitative real-time PCR assay, RA may inhibit bone metastasis from breast carcinoma mainly via the pathway of the receptor activator of NF kappaB ligand (RANKL)/RANK/osteoprotegerin (OPG) and by simultaneously suppressing the expression of interleukin-8 (IL-8). RA may thus be a good candidate for a new therapeutic approach in bone metastasis from breast carcinoma.