Docetaxel is the first-line chemotherapy for metastatic castration-resistant prostate cancer (PCa), the major cause of PCa mortality. Unfortunately, in most cases PCa develops docetaxel resistance and continues to progress, which has no cure. Our recent studies (Theranostics, 2021, May 8; 11: 6873-6890) have provided strong evidence demonstrating that chemoresistant PCa cells rely on an active EED-EZH2-Stat3-SKP2- ABCB1/survivin signaling to survive and evade standard chemotherapy. In this R01 project, we hypothesize that targeting EED-EZH2 interaction with novel EED inhibitors is effective to overcome chemoresistance and eliminate lethal PCa cells. In Aim 1, we will conduct rational design and chemical optimization of novel EED inhibitors. A total of 200 new chemical entities will be designed and synthesized. In Aim 2, We will validate the mechanism of action of potential leads in chemoresistant PCa cells. We will identify the in vitro and in vivo activities of new EED inhibitors against chemoresistant PCa in multiple, heterogenous preclinical models of chemoresistant PCa. In Aim 3, we will conduct Good Laboratory Practice (GLP) and non-GLP studies to evaluate the drug-like properties of lead compounds, including pharmacokinetics, absorption, distribution, metabolism, and excretion (ADME), single- and repeat-dose toxicity and safety pharmacology. With successful accomplishment of this project, we expect to identify 1~2 patentable lead compounds and advance them into further preclinical and clinical development. The overarching goal is to translate our basic research into an effective and safe treatment for lethal PCa, therefore benefiting patients and improving clinical outcomes.