A selective WDR5 degrader inhibits acute myeloid leukemia in patient-derived mouse models

Abstract

Interactions between WD40 repeat domain protein 5 (WDR5) and its various partners such as mixed lineage leukemia (MLL) and c-MYC are essential for sustaining oncogenesis in human cancers. However, inhibitors that block protein-protein interactions (PPIs) between WDR5 and its binding partners exhibit modest cancer cell killing effects and lack in vivo efficacy. Here, we present pharmacological degradation of WDR5 as a promising therapeutic strategy for treating WDR5-dependent tumors and report two high-resolution crystal structures of WDR5degrader-E3 ligase ternary complexes. We identified an effective WDR5 degrader via structure-based design and demonstrated its in vitro and in vivo antitumor activities. On the basis of the crystal structure of an initial WDR5 degrader in complex with WDR5 and the E3 ligase von Hippel-Lindau (VHL), we designed a WDR5 degrader, MS67, and demonstrated the high cooperativity of MS67 binding to WDR5 and VHL by another ternary complex structure and biophysical characterization. MS67 potently and selectively depleted WDR5 and was more effective than WDR5 PPI inhibitors in suppressing transcription of WDR5-regulated genes, decreasing the chromatin-bound fraction of MLL complex components and c-MYC, and inhibiting the proliferation of cancer cells. In addition, MS67 suppressed malignant growth of MLL-rearranged acute myeloid leukemia patient cells in vitro and in vivo and was well tolerated in vivo. Collectively, our results demonstrate that structure-based design can be an effective strategy to identify highly active degraders and suggest that pharmacological degradation of WDR5 might be a promising treatment for WDR5-dependent cancers.

A cryptic transactivation domain of EZH2 binds AR and AR’s splice variant promoting oncogene activation and tumorous transformation

“…Multiplexed RNA-seq libraries were subjected for deep sequencing. Reads were mapped to the reference genome followed by analysis of differentially expressed genes (DEG) as before (27,52). Fastq files were aligned to the GRCh38 human genome (GRCh38.d1.vd1.fa) using STAR v2.4.2 (53) with parameters: --outSAMtype BAM Unsorted --quantMode TranscriptomeSAM.…”

WDR5 promotes breast cancer growth and metastasis via KMT2-independent translation regulation

“…In fact, the WDR5 degrader MS67 showed superior effect than the WDR5 inhibitor OICR-9429. MS67 led to WDR5 degradation within 4 hours and is reversible after withdrawal of drug treatment (Yu et al, 2021), allowing for temporal control of WDR5 targeting. Unlike small molecule inhibitors, PROTAC molecules can be reused within the cells, which would lower the required concentration for drug treatment.…”

DOT1L activity in leukemia cells requires interaction with ubiquitylated H2B that promotes productive nucleosome binding

“…Leukemia cells grown in suspension were seeded at a density of 3 × 10 5 /mL in triplicate in 24-well plates and quantification was conducted as previously described ( Xu et al, 2015 ; Yu et al, 2021 ). Media was changed every two days.…”

“…Then, real-time PCR was performed using a QuantStudio 6 Flex Real-Time PCR platform (Thermo Fisher Scientific) and Power SYBR Green Master Mix (Bio-Rad). The comparative CT method was used to calculate relative gene expression by comparing the CT value of each target gene to that of an internal control GAPDH (2 ∆∆CT ) as follows: ∆∆CT = CT(target gene)–CT(GAPDH) ( Xu et al, 2015 ; Yu et al, 2021 ). Primers used for RT-qPCR are listed in Table S3 .…”