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Crystal structure of active CDK4-cyclin D and mechanistic basis for abemaciclib efficacy. NPJ Breast Cancer 2022; 8:126. [PMID: 36446794 PMCID: PMC9709041 DOI: 10.1038/s41523-022-00494-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 11/11/2022] [Indexed: 11/30/2022] Open
Abstract
Despite the biological and therapeutic relevance of CDK4/6 for the treatment of HR+, HER2- advanced breast cancer, the detailed mode of action of CDK4/6 inhibitors is not completely understood. Of particular interest, phosphorylation of CDK4 at T172 (pT172) is critical for generating the active conformation, yet no such crystal structure has been reported to date. We describe here the x-ray structure of active CDK4-cyclin D3 bound to the CDK4/6 inhibitor abemaciclib and discuss the key aspects of the catalytically-competent complex. Furthermore, the effect of CDK4/6 inhibitors on CDK4 T172 phosphorylation has not been explored, despite its role as a potential biomarker of CDK4/6 inhibitor response. We show mechanistically that CDK4/6i stabilize primed (pT172) CDK4-cyclin D complex and selectively displace p21 in responsive tumor cells. Stabilization of active CDK4-cyclin D1 complex can lead to pathway reactivation following alternate dosing regimen. Consequently, sustained binding of abemaciclib to CDK4 leads to potent cell cycle inhibition in breast cancer cell lines and prevents rebound activation of downstream signaling. Overall, our study provides key insights demonstrating that prolonged treatment with CDK4/6 inhibitors and composition of the CDK4/6-cyclin D complex are both critical determinants of abemaciclib efficacy, with implications for this class of anticancer therapy.
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Tu M, Klein L, Espinet E, Georgomanolis T, Wegwitz F, Li X, Urbach L, Danieli-Mackay A, Küffer S, Bojarczuk K, Mizi A, Günesdogan U, Chapuy B, Gu Z, Neesse A, Kishore U, Ströbel P, Hessmann E, Hahn SA, Trumpp A, Papantonis A, Ellenrieder V, Singh SK. TNF-α-producing macrophages determine subtype identity and prognosis via AP1 enhancer reprogramming in pancreatic cancer. NATURE CANCER 2021; 2:1185-1203. [PMID: 35122059 DOI: 10.1038/s43018-021-00258-w] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Accepted: 08/19/2021] [Indexed: 12/11/2022]
Abstract
Large-scale genomic profiling of pancreatic cancer (PDAC) has revealed two distinct subtypes: 'classical' and 'basal-like'. Their variable coexistence within the stromal immune microenvironment is linked to differential prognosis; however, the extent to which these neoplastic subtypes shape the stromal immune landscape and impact clinical outcome remains unclear. By combining preclinical models, patient-derived xenografts, as well as FACS-sorted PDAC patient biopsies, we show that the basal-like neoplastic state is sustained via BRD4-mediated cJUN/AP1 expression, which induces CCL2 to recruit tumor necrosis factor (TNF)-α-secreting macrophages. TNF-α+ macrophages force classical neoplastic cells into an aggressive phenotypic state via lineage reprogramming. Integration of ATAC-, ChIP- and RNA-seq data revealed distinct JUNB/AP1 (classical) and cJUN/AP1 (basal-like)-driven regulation of PDAC subtype identity. Pharmacological inhibition of BRD4 led to suppression of the BRD4-cJUN-CCL2-TNF-α axis, restoration of classical subtype identity and a favorable prognosis. Hence, patient-tailored therapy for a cJUNhigh/TNF-αhigh subtype is paramount in overcoming highly inflamed and aggressive PDAC states.
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Affiliation(s)
- Mengyu Tu
- Department of Gastroenterology, Gastrointestinal Oncology and Endocrinology, University Medical Center Göttingen, Göttingen, Germany
| | - Lukas Klein
- Department of Gastroenterology, Gastrointestinal Oncology and Endocrinology, University Medical Center Göttingen, Göttingen, Germany
| | - Elisa Espinet
- Division of Stem Cells and Cancer, DKFZ, Heidelberg, Germany
- Heidelberg Institute for Stem Cell Technology and Experimental Medicine (HI-STEM gGmbh), Heidelberg, Germany
| | | | - Florian Wegwitz
- Department of Gynecology and Obstetrics, University Medical Center Göttingen, Göttingen, Germany
| | - Xiaojuan Li
- Department of Developmental Biology, Göttingen Center for Molecular Biosciences, Göttingen, Germany
| | - Laura Urbach
- Department of Gastroenterology, Gastrointestinal Oncology and Endocrinology, University Medical Center Göttingen, Göttingen, Germany
| | - Adi Danieli-Mackay
- Institute of Pathology, University Medical Center Göttingen, Göttingen, Germany
| | - Stefan Küffer
- Institute of Pathology, University Medical Center Göttingen, Göttingen, Germany
| | - Kamil Bojarczuk
- Department of Hematology and Medical Oncology, University Medical Center Göttingen, Göttingen, Germany
| | - Athanasia Mizi
- Institute of Pathology, University Medical Center Göttingen, Göttingen, Germany
| | - Ufuk Günesdogan
- Department of Developmental Biology, Göttingen Center for Molecular Biosciences, Göttingen, Germany
| | - Björn Chapuy
- Department of Hematology and Medical Oncology, University Medical Center Göttingen, Göttingen, Germany
| | - Zuguang Gu
- Bioinformatics and Omics Data Analytics, DKFZ, Heidelberg, Germany
- Division of Cancer Epigenomics, DKFZ, Heidelberg, Germany
| | - Albrecht Neesse
- Department of Gastroenterology, Gastrointestinal Oncology and Endocrinology, University Medical Center Göttingen, Göttingen, Germany
| | - Uday Kishore
- Biosciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, UK
| | - Philipp Ströbel
- Institute of Pathology, University Medical Center Göttingen, Göttingen, Germany
| | - Elisabeth Hessmann
- Department of Gastroenterology, Gastrointestinal Oncology and Endocrinology, University Medical Center Göttingen, Göttingen, Germany
| | - Stephan A Hahn
- Faculty of Medicine, Department of Molecular GI Oncology, Ruhr University Bochum, Bochum, Germany
| | - Andreas Trumpp
- Division of Stem Cells and Cancer, DKFZ, Heidelberg, Germany
- Heidelberg Institute for Stem Cell Technology and Experimental Medicine (HI-STEM gGmbh), Heidelberg, Germany
| | - Argyris Papantonis
- Institute of Pathology, University Medical Center Göttingen, Göttingen, Germany
| | - Volker Ellenrieder
- Department of Gastroenterology, Gastrointestinal Oncology and Endocrinology, University Medical Center Göttingen, Göttingen, Germany
| | - Shiv K Singh
- Department of Gastroenterology, Gastrointestinal Oncology and Endocrinology, University Medical Center Göttingen, Göttingen, Germany.
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