show Abstracthide AbstractThe Polycomb-like protein PHF19/PCL3 associates with the Polycomb repressive complex 2 (PRC2) and mediates its recruitment to chromatin in embryonic stem cells, where it is essential for maintaining the repression of developmental genes. PHF19 is also overexpressed in many cancers. However, neither PHF19 targets in cancer cells nor potentially misregulated pathways involving PHF19 are known. Here, we investigate the role of PHF19 in prostate cancer cells. We find that PHF19 interacts with PRC2 and binds to PRC2 targets on chromatin. Direct PHF19 target genes are involved in proliferation, differentiation, angiogenesis, and extracellular matrix organization, among others. Depletion of PHF19 triggers an increase in MTF2/PCL2 recruitment to chromatin, along with a genome-wide gain in PRC2 occupancy and H3K27me3 deposition. Transcriptome analysis shows that loss of PHF19 promotes deregulation of key genes involved in growth, metastasis, and invasion, as well as of factors that stimulate formation of new blood vessels. Consistent with this, PHF19 silencing reduces cell proliferation rate and promotes invasive growth and angiogenesis. Taking together, our findings reveal a role for PHF19 in controlling the balance between cell proliferation and invasiveness in prostate cancer. Overall design: ChIP-seq (15 samples) and RNA-seq (8 samples) of prostate cancer cells (DU145). CTR means shRNA Control, SH4 means knock-down of PHF19 long isoform and SH168 means knock-down of PHF19 short isoform. R2 means second replicate.