Prostate cancer expression of runt-domain transcription factor Runx2, a key regulator of osteoblast differentiation and function.

BACKGROUND Prostate cancer (CaP) bone metastases express numerous proteins associated with bone cells. Specific transcription factors, including Runx2, regulate the expression of many bone-related factors in osteoblasts. Expression of these transcription factors in CaP may be linked to the ability of CaP bone metastases to influence bone remodeling. METHODS CaP tissues and cell lines were analyzed for expression of Runx2 mRNA by RT-PCR and in situ hybridization, and protein by immunohistochemistry, Western blotting, and electrophoretic mobility shift assays (EMSA). RESULTS Runx2 mRNA and protein were detected in CaP tissues and cell lines. A specific Runx2: OSE2 complex could be formed with PC-3 nuclear extracts. CONCLUSIONS Expression of Runx2 in CaP may be the molecular switch that is associated with expression of various bone-specific factors in CaP. In turn, expression of these factors can influence bone remodeling and possibly play a role in the growth and survival of CaP in bone.