Tumor suppressor RKIP inhibits prostate cancer cell metastasis and sensitizes prostate cancer cells to docetaxel treatment.

Raf kinase inhibitory protein (RKIP) is a well-established metastasis suppressor that is frequently down-regulated in aggressive cancers. However, the impact of RKIP on cancer cell invasion and metastasis in prostate cancer is still elusive. To this end, we overexpressed RKIP in two prostate cancer cell lines. We found that overexpression of RKIP inhibited prostate cancer cells proliferation, migration and invasion. Mechanistically, we found that RKIP overexpression led to down-regula- tion of the NF-kB signaling pathway and inhibition of the epithelial-to-mesenchymal transition, which is important step for cancer metastasis. In addition, overexpression of RKIP can promote drug effects of docetaxel on prostate cancer cell lines. In conclusion, overexpression of RKIP significantly inhibits prostate cancer cell migration and metastasis, and overexpression of RKIP could aid prostate cancer treatment and therapy.