Recent strategies targeting Embryonic Ectoderm Development (EED) for cancer therapy: Allosteric inhibitors, PPI inhibitors, and PROTACs

The polycomb repressive complex 2 (PRC2), which comprised of the core subunits: Enhancer of Zeste Homolog 2 (EZH2), Suppressor of Zeste 12 (SUZ12), and Embryonic Ectoderm Development (EED), is an essential epigenetic gene silencer responsible for depositing repressive histone H3 lysine 27 trimethylation (H3K27me3) marks on chromatin. The aberrant activity of PRC2 is closely involved in tumorigenesis and progression, making its inhibition a viable strategy for epigenetic cancer therapy. Although the clinical development of small PRC2 inhibitors has made impressive progress, with one EZH2 inhibitor approved for cancer therapy and several other candidates in clinical trials, current EZH2 inhibitors are limited to treating certain hematological malignancies and have acquired drug resistance. EED is essential for PRC2 stabilization and allosterically stimulating PRC2 activity because it functions as a scaffold protein and an H3K27me3-recognizing protein. Thus, due to its novel mechanism of action, targeting EED provides a promising new strategy for inhibiting PRC2 function and exhibits the potential to overcome the issues encountered by EZH2 inhibitors. This review provides a comprehensive overview of available cancer therapy strategies that target EED, including allosteric inhibitors, protein-protein interaction (PPI) inhibitors, and proteolysis-targeting chimeras (PROTACs).