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Project description: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 WDR5-degrader-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.
| S-EPMC8500670 | biostudies-literature
Project description:Biochemical interactions between WD40 repeat domain protein 5 (WDR5) and its various cellular partners such as Mixed Lineage Leukemia (MLL) and c-MYC are essential for sustaining oncogenesis in a range of human cancers. Thus, small molecules targeting WDR5 represent an attractive strategy for anti-cancer interventions. However, currently available inhibitors designed to interfere with WDR5 binding to a specific partner (such as OICR-9429 that blocks WDR5-MLL interaction) show a promising but rather partial therapeutic effect, presumably due to incomplete blockade of WDR5 functionality and interactions with various partners. Here, we report the first-in-class, OICR-9429-based proteolysis targeting chimeras (PROTACs) of WDR5, including a prototypic compound MS33 and a further optimized MS67, that achieve specific and efficient depletion of WDR5 in cancer cells. Such an effect is not seen with OICR-9429 or MS33/67 analogs that are incapable of E3 ligand conjugation. Medicinal chemistry, structural and cellular characterizations demonstrate that MS33 and MS67 bind both WDR5 and an E3 ligand VHL tightly, with MS67 showing a unique cooperative binding, an event that subsequently induces degradation of WDR5 through a VHL- and proteasome-dependent mechanism. Global proteomics profiling shows a highly specific effect of MS67 on WDR5. Genomics analysis further demonstrates that, relative to non-degrading inhibitors, MS67 is far more potent in suppressing overall transcription of WDR5-regulated genes crucially involved in oncogenesis and in reducing global H3K4 methylation, an enzymatic product of MLL/WDR5 complex. Importantly, using a panel of human MLL-rearranged acute myeloid leukemia (MLL-r AML) and pancreatic ductal adenocarcinoma (PDAC) cells, we found that, relative to non-degrading inhibitor controls, MS67 displays a superior anti-growth effect. MS67 also demonstrates optimal PK/PD properties in vivo and treatment with MS67 significantly suppressed tumorigenesis of MLL-r AML in tumor xenografted animal models. Together, this study reports the first-in-class PROTACs of WDR5 and demonstrates its advantageous efficacies in the treatment of WDR5-dependent cancers.
2021-09-29 | GSE150554 | GEO
Project description:Biochemical interactions between WD40 repeat domain protein 5 (WDR5) and its various cellular partners such as Mixed Lineage Leukemia (MLL) and c-MYC are essential for sustaining oncogenesis in a range of human cancers. Thus, small molecules targeting WDR5 represent an attractive strategy for anti-cancer interventions. However, currently available inhibitors designed to interfere with WDR5 binding to a specific partner (such as OICR-9429 that blocks WDR5-MLL interaction) show a promising but rather partial therapeutic effect, presumably due to incomplete blockade of WDR5 functionality and interactions with various partners. Here, we report the first-in-class, OICR-9429-based proteolysis targeting chimeras (PROTACs) of WDR5, including a prototypic compound MS33 and a further optimized MS67, that achieve specific and efficient depletion of WDR5 in cancer cells. Such an effect is not seen with OICR-9429 or MS33/67 analogs that are incapable of E3 ligand conjugation. Medicinal chemistry, structural and cellular characterizations demonstrate that MS33 and MS67 bind both WDR5 and an E3 ligand VHL tightly, with MS67 showing a unique cooperative binding, an event that subsequently induces degradation of WDR5 through a VHL- and proteasome-dependent mechanism. Global proteomics profiling shows a highly specific effect of MS67 on WDR5. Genomics analysis further demonstrates that, relative to non-degrading inhibitors, MS67 is far more potent in suppressing overall transcription of WDR5-regulated genes crucially involved in oncogenesis and in reducing global H3K4 methylation, an enzymatic product of MLL/WDR5 complex. Importantly, using a panel of human MLL-rearranged acute myeloid leukemia (MLL-r AML) and pancreatic ductal adenocarcinoma (PDAC) cells, we found that, relative to non-degrading inhibitor controls, MS67 displays a superior anti-growth effect. MS67 also demonstrates optimal PK/PD properties in vivo and treatment with MS67 significantly suppressed tumorigenesis of MLL-r AML in tumor xenografted animal models. Together, this study reports the first-in-class PROTACs of WDR5 and demonstrates its advantageous efficacies in the treatment of WDR5-dependent cancers.
2021-09-29 | GSE150552 | GEO
Project description:A selective WDR5 degrader inhibits acute myeloid leukemia in patient-derived mouse models
| PRJNA632759 | ENA
Project description:A selective WDR5 degrader inhibits acute myeloid leukemia in patient-derived mouse models [ChIP-seq]
| PRJNA632756 | ENA
Project description:A selective WDR5 degrader inhibits acute myeloid leukemia in patient-derived mouse models[RNA-seq]
| PRJNA632769 | ENA
Project description:Children with acute myeloid leukemia (AML) have a poor prognosis despite the intensification of chemotherapy. Future efforts to improve outcomes should focus on more precise targeting of leukemia cells. CD123, or IL3RA, is expressed on the surface of nearly all pediatric AML samples and is a high-priority target for immunotherapy. The efficacy of an investigational dual-affinity retargeting antibody (DART) molecule (CD123 × CD3; MGD006 or flotetuzumab) was assessed in two distinct patient-derived xenograft (PDX) models of pediatric AML. MGD006 simultaneously binds to CD123 on target cells and CD3 on effector T cells, thereby activating T cells and redirecting them to induce cytotoxicity in target cells. The concurrent treatment of cytarabine and MGD006 was performed to determine the effect of cytarabine on T-cell counts and MGD006 activity. Treatment with MGD006 along with an allogeneic human T-cell infusion to act as effector cells induced durable responses in both PDX models, with CD123 positivity. This effect was sustained in mice treated with a combination of MGD006 and cytarabine in the presence of T cells. MGD006 enhanced T-cell proliferation and decreased the burden of AML blasts in the peripheral blood with or without cytarabine treatment. These data demonstrate the efficacy of MGD006 in prolonging survival in pediatric AML PDX models in the presence of effector T cells and show that the inclusion of cytarabine in the treatment regimen does not interfere with MGD006 activity.
| S-EPMC8911345 | biostudies-literature
Project description:Acute myeloid leukemia (AML) in children remains deadly, despite the use of maximally intensive therapy. Because leukemia stem cells (LSCs) significantly contribute to chemoresistance and relapse, therapies that specifically target the LSCs are likely to be more beneficial in improving outcome. LSCs are known to have high telomerase activity and telomerase activity is negatively correlated with survival in pediatric AML. We evaluated the preclinical efficacy of imetelstat, an oligonucleotide inhibitor of telomerase activity in patient-derived xenograft (PDX) lines of pediatric AML. Imetelstat treatment significantly increased apoptosis/death of the LSC population in a dose-dependent manner in six pediatric AML PDX lines ex vivo, while it had limited activity on the stem cell population in normal bone marrow specimens. These results were validated in vivo in two distinct PDX models wherein imetelstat as single agent or in combination with chemotherapy greatly reduced the LSC percentage and prolonged median survival. Imetelstat combination with DNA hypomethylating agent azacitidine was also beneficial in extending survival. Secondary transplantation experiments showed delayed engraftment and improved survival of mice receiving imetelstat-treated cells, confirming the diminished LSC population. Thus, our data suggest that imetelstat represents an effective therapeutic strategy for pediatric AML.
| S-EPMC8999576 | biostudies-literature
Project description: Not available
| S-EPMC5102776 | biostudies-literature
Project description:We studied acute myeloid leukemia (AML) patients with lympho-myeloid clonal hematopoiesis (LM-CH), defined by the presence of DNA methyltransferase 3A (DNMT3A) mutations in both the myeloid and lymphoid T-cell compartment. Diagnostic, complete remission (CR) and relapse samples were sequenced for 34 leukemia-related genes in 171 DNMT3A mutated adult AML patients. AML with LM-CH was found in 40 patients (23%) and was associated with clonal hematopoiesis of indeterminate potential years before AML, older age, secondary AML and more frequent MDS-type co-mutations (TET2, RUNX1 and EZH2). In 82% of AML patients with LM-CH, the preleukemic clone was refractory to chemotherapy and was the founding clone for relapse. Both LM-CH and non-LM-CH MRD-positive AML patients who achieved CR had a high risk of relapse after 10 years (75% and 75%, respectively) compared with patients without clonal hematopoiesis in CR with negative MRD (27% relapse rate). Long-term survival of patients with LM-CH was only seen after allogeneic hematopoietic stem cell transplantation (HSCT). We define AML patients with LM-CH as a distinct high-risk group of AML patients that can be identified at diagnosis through mutation analysis in T cells and should be considered for HSCT.
| S-EPMC7610466 | biostudies-literature