Epigenetic regulators: Polycomb-miRNA circuits in cancer

• The polycomb group (PcGs) of proteins has epigenetic regulatory functions.
• PcGs exert epigenetic regulation through the binding of long-ncRNAs.
• PcGs: epigenetic mechanism of miRNA modifications
• Interplay between miRNAs and PcGs
• Therapeutic potential of PcG targeting in cancer

Polycomb group (PcG) proteins belong to a family of epigenetic modifiers and play a key role in dynamic control of their target genes. Several reports have found that aberrations in PcG-microRNA (miRNA) interplay in various cancer types often associated with poor clinical prognosis. This review discusses important PcG-miRNA molecular networks which act as critical interfaces between chromatin remodeling, and transcriptional and post-transcriptional regulation of their target genes in cancer. Moreover, here are discussed several compounds influencing the activity of PcG proteins entered in clinical arena for the treatment of solid tumors, multiple myeloma and B lymphomas, thus highlighting the therapeutic potential of targeting this protein family.