Small-Molecule Modulators Targeting Coactivator-Associated Arginine Methyltransferase 1 (CARM1) as Therapeutic Agents for Cancer Treatment: Current Medicinal Chemistry Insights and Emerging Opportunities

Overexpression of coactivator associated arginine methyltransferase 1 (CARM1) is associated with various diseases including cancer. Therefore, CARM1 has emerged as an attractive therapeutic target and a drug response biomarker for anticancer drug discovery. However, the development of conventional CARM1 inhibitors has been hampered by their limited clinical efficacy, acquired resistance, and inability to inhibit nonenzymatic functions of CARM1. To overcome these challenges, new strategies such as isoform-selective inhibitors, dual-acting inhibitors, targeted protein degradation technology (e.g., PROTACs), and even activators, are essential to enhance the anticancer activity of CARM1 modulators. In this perspective, we first summarize the structure and biofunctions of CARM1 and its association with cancer. Next, we focus on the recent advances in CARM1 modulators, including isoform-selective CARM1 inhibitors, dual-target inhibitors, PROTAC degraders, and activators, from the perspectives of rational design, pharmacodynamics, pharmacokinetics, and clinical status. Finally, we discuss the challenges and future directions for CARM1-based drug discovery.