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Discovery of a selective CDK7 PROTAC against acute leukemia with low platelet toxicity
Yutong Tu1, Xiaojia Cai2,3, Zhaofan Tao2,3
1Zhongshan Institute for Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Zhongshan, China.
Abstract:
Cyclin-dependent kinase 7 (CDK7), a key regulator of cell cycle progression and transcriptional control, has emerged as a promising therapeutic target in acute leukemia. While CDK7 inhibitors have shown antileukemic activity, their clinical utility is often restricted by dose-dependent thrombocytopenia. To overcome this challenge, we developed and characterized a series of CDK7-selective PROTAC degraders. By engaging the VHL E3 ligase, which is minimally expressed in platelets, CXJ2080 achieves tumor-selective CDK7 degradation with remarkable potency and selectivity (a DC50 of 0.88 nM and >98% degradation efficiency). This selective targeting spares platelets, thereby avoiding the hematologic toxicity associated with conventional CDK7 inhibitors. Mechanistically, CDK7 degradation disrupts the CDK7-cyclin H-MAT1 complex, simultaneously suppressing MYC-driven oncogenic signaling while activating the p53-p21 tumor suppressor axis. These effects have culminated in robust antileukemic activity in preclinical models, while preserving normal peripheral blood mononuclear cell (PBMC) function. Collectively, our findings establish CXJ2080 as a next-generation CDK7-targeted therapeutic agent with enhanced efficacy and reduced hematotoxicity, showing great promise for the treatment of acute leukemia.
Insights
A novel PROTAC degrader, CXJ2080, targets cyclin-dependent kinase 7 (CDK7) in acute leukemia. This approach reduces thrombocytopenia, offering a promising therapeutic strategy with enhanced efficacy and reduced toxicity.
Area of Science:
- Oncology
- Molecular Biology
- Pharmacology
Background:
- Cyclin-dependent kinase 7 (CDK7) is crucial for cell cycle and transcription, making it a therapeutic target in acute leukemia.
- Conventional CDK7 inhibitors cause dose-dependent thrombocytopenia, limiting clinical application.
Purpose of the Study:
- To develop novel CDK7-selective Proteolysis-Targeting Chimeras (PROTACs) to overcome the limitations of existing inhibitors.
- To evaluate the efficacy and safety profile of a lead compound, CXJ2080, in preclinical models of acute leukemia.
Main Methods:
- Design and characterization of CDK7-selective PROTAC degraders.
- Assessment of compound potency, selectivity, and degradation efficiency using biochemical and cellular assays.
- Evaluation of antileukemic activity and hematotoxicity in relevant preclinical models.
Main Results:
- CXJ2080 demonstrated potent and selective CDK7 degradation (DC50 of 0.88 nM) by engaging the VHL E3 ligase, sparing platelets.
- Degradation of CDK7 disrupted the CDK7-cyclin H-MAT1 complex, suppressing MYC signaling and activating p53-p21.
- CXJ2080 exhibited robust antileukemic activity in preclinical models with minimal impact on normal peripheral blood mononuclear cell function.
Conclusions:
- CXJ2080 represents a next-generation therapeutic agent for acute leukemia, offering enhanced efficacy through selective CDK7 targeting.
- This PROTAC degrader approach effectively mitigates the hematotoxicity associated with conventional CDK7 inhibitors, paving the way for improved patient outcomes.
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