By using specific small hairpin RNAs for MAPK11, we demonstrated that p38β-mediated p38 activity in breast cancer cells is responsible for breast cancer-induced osteolytic bone destruction.
Myeloma cells with high/detectable p38 activity, but not those with low/undetectable p38 activity, injected into severe combined immunodeficient (SCID) or SCID-hu mice caused bone destruction.
Thus, our data show that developing specific inhibitors of the alpha-isoenzyme of p38 would be beneficial for the treatment of inflammation-induced bone destruction as observed in rheumatoid arthritis.