The Polycomb Group protein EZH2 regulates actin polymerization in human prostate cancer cells.
Bryant RJ., Winder SJ., Cross SS., Hamdy FC., Cunliffe VT.
BACKGROUND: The Polycomb Group protein EZH2 is implicated in prostate cancer progression. EZH2 promotes prostate cancer cell proliferation and invasiveness. We describe a link between EZH2 function and actin polymerization in prostate cancer cells. METHODS: Nuclear and cytoplasmic EZH2 expression in benign and malignant prostate tissue samples was assessed. An association between EZH2 function and actin polymerization in prostate cancer cells was investigated using siRNA-mediated knock-down of EZH2. Effects of EZH2 knock-down on actin polymerization dynamics were analyzed biochemically using immunoblot analysis of cell lysate fractions, and morphologically using immunocytochemistry. RESULTS: Cytoplasmic EZH2 is expressed at low levels in benign prostate epithelial cells and over-expressed in prostate cancer cells. Cytoplasmic EZH2 expression levels correlate with nuclear EZH2 expression in prostate cancer samples. Knock-down of EZH2 in PC3 prostate cancer cells increases the amount of F-actin polymerization, cell size, and formation of actin-rich filaments. CONCLUSIONS: Cytoplasmic EZH2 is over-expressed in prostate cancer cells. EZH2 function promotes a reduction in the pool of insoluble F-actin in invasive prostate cancer cells. EZH2 may regulate actin polymerization dynamics and thereby promote prostate cancer cell motility and invasiveness.