Microvesicles released from hormone-refractory prostate cancer cells facilitate mouse pre-osteoblast differentiation.

Bone metastasis is often occurs in patients with prostate cancer. There is a vicious cycle for bone metastases involving prostate cancer cells, osteoblasts, and osteoclasts. Acting among those cells during the process of metastasis are several molecules such as bone morphogenetic proteins, platelet-derived growth factor, endothelin-1, matrix metalloproteases, vascular endothelial growth factor, transforming growth factor-β, and insulin-like growth factors. Cell-derived microvesicles are endogenous carriers transporting proteins, mRNAs and miRNAs between cells, which is a candidate for participation in the bone metastasis of these cells. Here, we demonstrated that prostate cancer cells in vitro released microvesicles into the culture medium (PCa-MVs), which was shown by electron microscopic study and nanoparticle tracking analysis. In this study, we found for the first time that these PCa-MVs enhanced osteoblast differentiation mainly through the delivery of PCa cell-derived v-ets erythroblastosis virus E26 oncogene homolog 1, which is an osteoblast differentiation related-transcriptional factor.