Discovery of CRBN-recruiting PROTAC degraders of the METTL3-METTL14 complex

METTL3 and METTL14, key components of the m⁶A writer complex, are frequently overexpressed in various malignancies, including acute myeloid leukemia (AML), where aberrant methylation has been linked to the upregulation of oncogenic transcription. Therefore, targeting the METTL3/METTL14 complex represents a potential therapeutic approach for AML. Although several METTL3 inhibitors have been discovered, their SAM-competitive mode of action often results in reduced cellular potency, prompting interest in alternative strategies such as targeted protein degradation. In this article, we expand upon reported METTL3/METTL14 complex degraders through exploration of CRBN-recruiting proteolysis-targeting chimeras (PROTACs) from multiple exit vectors of UZH2, a reported METTL3 inhibitor. The most potent PROTAC, 4j, demonstrated sub-micromolar degradation potency in MV4.11 cells with DC₅₀ values of 0.44 µM for METTL3 and 0.13 µM for METTL14. Notably, 4j showed enhanced cytotoxicity in MV4.11 cells compared to well-validated METTL3 inhibitors, underscoring the therapeutic potential of targeted degradation of the METTL3/METTL14 complex in AML.