Enhancer of zeste homolog 2 (EZH2) plays a crucial role in embryonic and somatic 
stem cells for their proliferation and differentiation. However, the roles and 
underlying mechanisms of EZH2 in prostate cancer stem cells (PCSCs) remain 
unknown. This study aimed to investigate the effects of EZH2 on PCSCs. PCSCs 
were isolated from the human prostate cancer cell line LNcap by fluorescence 
activated cell sorting (FACS). EZH2 expression was compared between PCSCs and 
non-PCSCs. The association between EZH2 function and PCSC growth was 
investigated using siRNA-mediated knock-down of EZH2. Cell growth was 
investigated by MTT, cell cycle and apoptosis of PCSCs were explored by flow 
cytometric analysis. Finally, the upstream pathway miRNA level was determined 
via a luciferase reporter assay, and the downstream pathway cycle regulators 
were examined via reverse transcriptase-polymerase chain reaction. The results 
showed that LNcap cell line comprised a greater proportion of CD44+/CD133+ cells 
by comparison to the PC-3 cell line. EZH2 was up-regulated in PCSCs compared 
with non-PCSCs. Silence of EZH2 inhibited cell growth and the cell cycle and 
promoted the progression of apoptosis. Furthermore, EZH2 was a direct target of 
miR-101 in PCSCs and EZH2's mRNA levels were inversely correlated with miR-101 
expression and cyclin E2 (a cell-cycle regulator) was suppressed by siEZH2. In 
conclusion, EZH2 is essential for PCSC growth, partly through a negative 
regulation by miR-101 and positively regulating cyclin E2.