ChIP analysis was performed as reported previously (14 (link)) by using 5 μg rabbit α-SNAIL (R&D system), α-EZH2 (Active motif) or the negative control normal rabbit immunoglobulin (IgG) (Millipore Corp., Bedford, MA) or normal goat immunoglobulin (IgG) (R&D system). 5 ng of immunoprecipitated DNA and the relative controls were used as templates for real-time qPCR analysis, performed in triplicate. qPCR analysis of the immunoprecipitated samples and of the negative controls (IgG) were both normalized to total chromatin input and expressed as percentage of Input (% Input). Histone ChIP analysis was performed by using 5 μg of the specific antibody (H3K27me3; 07-449; Millipore Corp., Bedford, MA) or of the negative control normal rabbit IgG (Millipore Corp., Bedford, MA), as reported previously (14 (link)). The DNA was extracted with phenol-chloroform, precipitated with ethanol and resuspended in 50μl of water, then used in the downstream qPCR analyses (primer pairs details are listed in Table S2).