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Li X, Liu M, Xing Y, Niu Y, Liu TH, Sun JL, Liu Y, Hemba-Waduge RUS, Ji JY. Distinct effects of CDK8 module subunits on cellular growth and proliferation in Drosophila. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.30.591924. [PMID: 38746212 PMCID: PMC11092604 DOI: 10.1101/2024.04.30.591924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
The Mediator complex, composed of about 30 conserved subunits, plays a pivotal role in facilitating RNA polymerase II-dependent transcription in eukaryotes. Within this complex, the CDK8 kinase module (CKM), comprising Med12, Med13, CDK8, and CycC (Cyclin C), serves as a dissociable subcomplex that modulates the activity of the small Mediator complex. Genetic studies in Drosophila have revealed distinct phenotypes of CDK8-CycC and Med12-Med13 mutations, yet the underlying mechanism has remained unknown. Here, using Drosophila as a model organism, we show that depleting CDK8-CycC enhances E2F1 target gene expression and promotes cell-cycle progression. Conversely, depletion of Med12-Med13 affects the expression of ribosomal protein genes and fibrillarin, indicating a more severe reduction in ribosome biogenesis and cellular growth compared to the loss of CDK8-CycC. Moreover, we found that the stability of CDK8 and CycC relies on Med12 and Med13, with a mutually interdependent relationship between Med12 and Med13. Furthermore, CycC stability depends on the other three CKM subunits. These findings reveal distinct roles for CKM subunits in vivo , with Med12-Med13 disruption exerting a more pronounced impact on ribosome biogenesis and cellular growth compared to the loss of CDK8-CycC. Significance The CDK8 kinase module (CKM), comprising CDK8, CycC, Med12, and Med13, is essential in the Mediator complex for RNA polymerase II-dependent transcription in eukaryotes. While expected to function jointly, CKM subunit mutations result in distinct phenotypes in Drosophila . This study investigates the mechanisms driving these differing effects. Our analysis reveals the role of Med12-Med13 pair in regulating ribosomal biogenesis and cellular growth, contrasting with the involvement of CDK8-CycC in E2F1-dependent cell-cycle progression. Additionally, an asymmetric interdependence in the stability of CDK8-CycC and Med12-Med13 was observed. CKM mutations or overexpression are associated with cancers and cardiovascular diseases. Our findings underscore the distinct impacts of CKM mutations on cellular growth and proliferation, advancing our understanding of their diverse consequences in vivo .
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Xie S, Zhang S, de Medeiros G, Liberali P, Skotheim JM. The G1/S transition in mammalian stem cells in vivo is autonomously regulated by cell size. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.09.588781. [PMID: 38645246 PMCID: PMC11030448 DOI: 10.1101/2024.04.09.588781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Cell growth and division must be coordinated to maintain a stable cell size, but how this coordination is implemented in multicellular tissues remains unclear. In unicellular eukaryotes, autonomous cell size control mechanisms couple cell growth and division with little extracellular input. However, in multicellular tissues we do not know if autonomous cell size control mechanisms operate the same way or whether cell growth and cell cycle progression are separately controlled by cell-extrinsic signals. Here, we address this question by tracking single epidermal stem cells growing in adult mice. We find that a cell-autonomous size control mechanism, dependent on the RB pathway, sets the timing of S phase entry based on the cell's current size. Cell-extrinsic variations in the cellular microenvironment affect cell growth rates but not this autonomous coupling. Our work reassesses long-standing models of cell cycle regulation within complex metazoan tissues and identifies cell-autonomous size control as a critical mechanism regulating cell divisions in vivo and thereby a major contributor to stem cell heterogeneity.
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Wu H, Kren BT, Lane AN, Cassel TA, Higashi RM, Fan TWM, Scaria GS, Shekels LL, Klein MA, Albrecht JH. Cyclin D1 extensively reprograms metabolism to support biosynthetic pathways in hepatocytes. J Biol Chem 2023; 299:105407. [PMID: 38152849 PMCID: PMC10687208 DOI: 10.1016/j.jbc.2023.105407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 10/15/2023] [Accepted: 10/17/2023] [Indexed: 12/29/2023] Open
Abstract
Cell proliferation requires metabolic reprogramming to accommodate biosynthesis of new cell components, and similar alterations occur in cancer cells. However, the mechanisms linking the cell cycle machinery to metabolism are not well defined. Cyclin D1, along with its main partner cyclin-dependent kinase 4 (Cdk4), is a pivotal cell cycle regulator and driver oncogene that is overexpressed in many cancers. Here, we examine hepatocyte proliferation to define novel effects of cyclin D1 on biosynthetic metabolism. Metabolomic studies reveal that cyclin D1 broadly promotes biosynthetic pathways including glycolysis, the pentose phosphate pathway, and the purine and pyrimidine nucleotide synthesis in hepatocytes. Proteomic analyses demonstrate that overexpressed cyclin D1 binds to numerous metabolic enzymes including those involved in glycolysis and pyrimidine synthesis. In the glycolysis pathway, cyclin D1 activates aldolase and GAPDH, and these proteins are phosphorylated by cyclin D1/Cdk4 in vitro. De novo pyrimidine synthesis is particularly dependent on cyclin D1. Cyclin D1/Cdk4 phosphorylates the initial enzyme of this pathway, carbamoyl-phosphate synthetase 2, aspartate transcarbamylase, and dihydroorotase (CAD), and metabolomic analysis indicates that cyclin D1 depletion markedly reduces the activity of this enzyme. Pharmacologic inhibition of Cdk4 along with the downstream pyrimidine synthesis enzyme dihydroorotate dehydrogenase synergistically inhibits proliferation and survival of hepatocellular carcinoma cells. These studies demonstrate that cyclin D1 promotes a broad network of biosynthetic pathways in hepatocytes, and this model may provide insights into potential metabolic vulnerabilities in cancer cells.
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Affiliation(s)
- Heng Wu
- Division of Gastroenterology, Hepatology, and Nutrition, University of Minnesota, Minneapolis, Minnesota, USA
| | - Betsy T Kren
- Research Service, Minneapolis VA Health Care System, Minneapolis, Minnesota, USA
| | - Andrew N Lane
- Center for Environmental and Systems Biochemistry, Department of Toxicology and Cancer Biology, and Markey Cancer Center, University of Kentucky, Lexington, Kentucky, USA
| | - Teresa A Cassel
- Center for Environmental and Systems Biochemistry, Department of Toxicology and Cancer Biology, and Markey Cancer Center, University of Kentucky, Lexington, Kentucky, USA
| | - Richard M Higashi
- Center for Environmental and Systems Biochemistry, Department of Toxicology and Cancer Biology, and Markey Cancer Center, University of Kentucky, Lexington, Kentucky, USA
| | - Teresa W M Fan
- Center for Environmental and Systems Biochemistry, Department of Toxicology and Cancer Biology, and Markey Cancer Center, University of Kentucky, Lexington, Kentucky, USA
| | - George S Scaria
- Hematology and Oncology Division, Minneapolis VA Health Care System, Minneapolis, Minnesota, USA
| | - Laurie L Shekels
- Research Service, Minneapolis VA Health Care System, Minneapolis, Minnesota, USA
| | - Mark A Klein
- Hematology and Oncology Division, Minneapolis VA Health Care System, Minneapolis, Minnesota, USA
| | - Jeffrey H Albrecht
- Division of Gastroenterology, Hepatology, and Nutrition, University of Minnesota, Minneapolis, Minnesota, USA.
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Foy R, Crozier L, Pareri AU, Valverde JM, Park BH, Ly T, Saurin AT. Oncogenic signals prime cancer cells for toxic cell overgrowth during a G1 cell cycle arrest. Mol Cell 2023; 83:4047-4061.e6. [PMID: 37977117 DOI: 10.1016/j.molcel.2023.10.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 07/10/2023] [Accepted: 10/17/2023] [Indexed: 11/19/2023]
Abstract
CDK4/6 inhibitors are remarkable anti-cancer drugs that can arrest tumor cells in G1 and induce their senescence while causing only relatively mild toxicities in healthy tissues. How they achieve this mechanistically is unclear. We show here that tumor cells are specifically vulnerable to CDK4/6 inhibition because during the G1 arrest, oncogenic signals drive toxic cell overgrowth. This overgrowth causes permanent cell cycle withdrawal by either preventing progression from G1 or inducing genotoxic damage during the subsequent S-phase and mitosis. Inhibiting or reverting oncogenic signals that converge onto mTOR can rescue this excessive growth, DNA damage, and cell cycle exit in cancer cells. Conversely, inducing oncogenic signals in non-transformed cells can drive these toxic phenotypes and sensitize the cells to CDK4/6 inhibition. Together, this demonstrates that cell cycle arrest and oncogenic cell growth is a synthetic lethal combination that is exploited by CDK4/6 inhibitors to induce tumor-specific toxicity.
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Affiliation(s)
- Reece Foy
- Cellular and Systems Medicine, Jacqui Wood Cancer Centre, School of Medicine, University of Dundee, Dundee DD1 9SY, UK
| | - Lisa Crozier
- Cellular and Systems Medicine, Jacqui Wood Cancer Centre, School of Medicine, University of Dundee, Dundee DD1 9SY, UK
| | - Aanchal U Pareri
- Cellular and Systems Medicine, Jacqui Wood Cancer Centre, School of Medicine, University of Dundee, Dundee DD1 9SY, UK
| | - Juan Manuel Valverde
- Cellular and Systems Medicine, Jacqui Wood Cancer Centre, School of Medicine, University of Dundee, Dundee DD1 9SY, UK
| | - Ben Ho Park
- Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Tony Ly
- Molecular Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Adrian T Saurin
- Cellular and Systems Medicine, Jacqui Wood Cancer Centre, School of Medicine, University of Dundee, Dundee DD1 9SY, UK.
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Zhang L, Tang R, Wu Y, Liang Z, Liu J, Pi J, Zhang H. The Role and Mechanism of Retinol and Its Transformation Product, Retinoic Acid, in Modulating Oxidative Stress-Induced Damage to the Duck Intestinal Epithelial Barrier In Vitro. Animals (Basel) 2023; 13:3098. [PMID: 37835704 PMCID: PMC10572057 DOI: 10.3390/ani13193098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 09/24/2023] [Accepted: 09/28/2023] [Indexed: 10/15/2023] Open
Abstract
This study aimed to investigate the effects and mechanisms of retinol and retinoic acid on primary duck intestinal epithelial cells under oxidative stress induced by H2O2. Different ratios of retinol and retinoic acid were used for treatment. The study evaluated the cell morphology, viability, antioxidative capacity, and barrier function of cells. The expression of genes related to oxidative stress and the intestinal barrier was analyzed. The main findings demonstrated that the treated duck intestinal epithelial cells exhibited increased viability, increased antioxidative capacity, and improved intestinal barrier function compared to the control group. High retinoic acid treatment improved viability and gene expression, while high retinol increased antioxidative indicators and promoted intestinal barrier repair. Transcriptome analysis revealed the effects of treatments on cytokine interactions, retinol metabolism, PPAR signaling, and cell adhesion. In conclusion, this study highlights the potential of retinol and retinoic acid in protecting and improving intestinal cell health under oxidative stress, providing valuable insights for future research.
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Affiliation(s)
- Li Zhang
- Institute of Animal Husbandry and Veterinary Science, Hubei Academy of Agricultural Sciences, Wuhan 430064, China; (L.Z.); (R.T.); (Y.W.); (Z.L.); (J.P.)
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China;
| | - Rui Tang
- Institute of Animal Husbandry and Veterinary Science, Hubei Academy of Agricultural Sciences, Wuhan 430064, China; (L.Z.); (R.T.); (Y.W.); (Z.L.); (J.P.)
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China;
| | - Yan Wu
- Institute of Animal Husbandry and Veterinary Science, Hubei Academy of Agricultural Sciences, Wuhan 430064, China; (L.Z.); (R.T.); (Y.W.); (Z.L.); (J.P.)
| | - Zhenhua Liang
- Institute of Animal Husbandry and Veterinary Science, Hubei Academy of Agricultural Sciences, Wuhan 430064, China; (L.Z.); (R.T.); (Y.W.); (Z.L.); (J.P.)
| | - Jingbo Liu
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China;
| | - Jinsong Pi
- Institute of Animal Husbandry and Veterinary Science, Hubei Academy of Agricultural Sciences, Wuhan 430064, China; (L.Z.); (R.T.); (Y.W.); (Z.L.); (J.P.)
| | - Hao Zhang
- Institute of Animal Husbandry and Veterinary Science, Hubei Academy of Agricultural Sciences, Wuhan 430064, China; (L.Z.); (R.T.); (Y.W.); (Z.L.); (J.P.)
- Hubei Key Laboratory of Animal Embryo Engineering and Molecular Breeding, Wuhan 430064, China
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