1
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Kschonsak YT, Gao X, Miller SE, Hwang S, Marei H, Wu P, Li Y, Ruiz K, Dorighi K, Holokai L, Perampalam P, Tsai WTK, Kee YS, Agard NJ, Harris SF, Hannoush RN, de Sousa E Melo F. Potent and selective binders of the E3 ubiquitin ligase ZNRF3 stimulate Wnt signaling and intestinal organoid growth. Cell Chem Biol 2024; 31:1176-1187.e10. [PMID: 38056465 DOI: 10.1016/j.chembiol.2023.11.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 08/21/2023] [Accepted: 11/10/2023] [Indexed: 12/08/2023]
Abstract
Selective and precise activation of signaling transduction cascades is key for cellular reprogramming and tissue regeneration. However, the development of small- or large-molecule agonists for many signaling pathways has remained elusive and is rate limiting to realize the full clinical potential of regenerative medicine. Focusing on the Wnt pathway, here we describe a series of disulfide-constrained peptides (DCPs) that promote Wnt signaling activity by modulating the cell surface levels of ZNRF3, an E3 ubiquitin ligase that controls the abundance of the Wnt receptor complex FZD/LRP at the plasma membrane. Mechanistically, monomeric DCPs induce ZNRF3 ubiquitination, leading to its cell surface clearance, ultimately resulting in FZD stabilization. Furthermore, we engineered multimeric DCPs that induce expansive growth of human intestinal organoids, revealing a dependence between valency and ZNRF3 clearance. Our work highlights a strategy for the development of potent, biologically active Wnt signaling pathway agonists via targeting of ZNRF3.
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Affiliation(s)
- Yvonne T Kschonsak
- Department of Discovery Oncology, Genentech Inc, South San Francisco, CA 94080, USA.
| | - Xinxin Gao
- Department of Early Discovery Biochemistry and Peptide Therapeutics, Genentech Inc, South San Francisco, CA 94080, USA.
| | - Stephen E Miller
- Department of Early Discovery Biochemistry and Peptide Therapeutics, Genentech Inc, South San Francisco, CA 94080, USA
| | - Sunhee Hwang
- Department of Early Discovery Biochemistry and Peptide Therapeutics, Genentech Inc, South San Francisco, CA 94080, USA
| | - Hadir Marei
- Department of Discovery Oncology, Genentech Inc, South San Francisco, CA 94080, USA
| | - Ping Wu
- Department of Structural Biology, Genentech Inc, South San Francisco, CA 94080, USA
| | - Yanjie Li
- Department of Early Discovery Biochemistry and Peptide Therapeutics, Genentech Inc, South San Francisco, CA 94080, USA
| | - Karen Ruiz
- Department of Discovery Oncology, Genentech Inc, South San Francisco, CA 94080, USA
| | - Kristel Dorighi
- Department of Molecular Biology, Genentech Inc, South San Francisco, CA 94080, USA
| | - Loryn Holokai
- Department of Biomarker Discovery, Genentech Inc, South San Francisco, CA 94080, USA
| | - Pirunthan Perampalam
- ProCogia Inc. under contract to Hoffmann-La Roche Limited, Toronto, Ontario M5J2P1, Canada
| | - Wen-Ting K Tsai
- Department of Antibody Engineering, Genentech Inc, South San Francisco, CA 94080, USA
| | - Yee-Seir Kee
- Department of Antibody Engineering, Genentech Inc, South San Francisco, CA 94080, USA
| | - Nicholas J Agard
- Department of Antibody Engineering, Genentech Inc, South San Francisco, CA 94080, USA
| | - Seth F Harris
- Department of Structural Biology, Genentech Inc, South San Francisco, CA 94080, USA
| | - Rami N Hannoush
- Department of Early Discovery Biochemistry and Peptide Therapeutics, Genentech Inc, South San Francisco, CA 94080, USA.
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2
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Cong Y, Zhang T, Li H, Pan J, Qiu J. Ho(III)-coordination Complex: Fluorescence Performances and Combined with Captopril-Hydrogels against Glioma. J Fluoresc 2024:10.1007/s10895-024-03600-4. [PMID: 38329605 DOI: 10.1007/s10895-024-03600-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 01/23/2024] [Indexed: 02/09/2024]
Abstract
In this study, a novel dinuclear lanthanide complex, denoted as [Ho2(L)2(acac)2(CH3OH)2]·CH3OH (1) (where H2L is 2-[((4-methyl)-2-(carboxyl)-imino)]methyl]-8-hydroxyquinoline, and Hacac is acetylacetonate), was successfully synthesized and characterized using single-crystal and elemental analysis, with the auxiliary ligand β-diketonate and the 8-hydroxyquinoline Schiff base derivative serving as the foundation. Through ligand-to-metal charge transfer, Compound 1 demonstrated remarkable green fluorescence properties, showcasing potential applications in green fluorescence materials and fluorescence sensing. Additionally, Hyaluronic Acid (HA)/Carboxymethyl Chitosan (CMCS) hydrogels were synthesized through a chemical method. Utilizing captopril as a drug model, a novel metal gel granule of captopril was developed and assessed for its inhibitory activity against glioma cells. Molecular docking simulations revealed that only the methanol group in the Ho complex could contribute a polar atom for the formation of binding interactions.
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Affiliation(s)
- Yuwei Cong
- Department of Pathology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China.
| | - Tingting Zhang
- Harbin Center for Disease Control and Prevention, Harbin, Heilongjiang, China
| | - Heng Li
- Department of Pathology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Jie Pan
- Department of Oncology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Jiping Qiu
- Department of Pathology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
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3
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Lee H, Camuto CM, Niehrs C. R-Spondin 2 governs Xenopus left-right body axis formation by establishing an FGF signaling gradient. Nat Commun 2024; 15:1003. [PMID: 38307837 PMCID: PMC10837206 DOI: 10.1038/s41467-024-44951-7] [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: 06/13/2023] [Accepted: 01/10/2024] [Indexed: 02/04/2024] Open
Abstract
Establishment of the left-right (LR, sinistral, dextral) body axis in many vertebrate embryos relies on cilia-driven leftward fluid flow within an LR organizer (LRO). A cardinal question is how leftward flow triggers symmetry breakage. The chemosensation model posits that ciliary flow enriches a signaling molecule on the left side of the LRO that promotes sinistral cell fate. However, the nature of this sinistralizing signal has remained elusive. In the Xenopus LRO, we identified the stem cell growth factor R-Spondin 2 (Rspo2) as a symmetrically expressed, sinistralizing signal. As predicted for a flow-mediated signal, Rspo2 operates downstream of leftward flow but upstream of the asymmetrically expressed gene dand5. Unexpectedly, in LR patterning, Rspo2 acts as an FGF receptor antagonist: Rspo2 via its TSP1 domain binds Fgfr4 and promotes its membrane clearance by Znrf3-mediated endocytosis. Concordantly, we find that at flow-stage, FGF signaling is dextralizing and forms a gradient across the LRO, high on the dextral- and low on the sinistral side. Rspo2 gain- and loss-of function equalize this FGF signaling gradient and sinistralize and dextralize development, respectively. We propose that leftward flow of Rspo2 produces an FGF signaling gradient that governs LR-symmetry breakage.
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Affiliation(s)
- Hyeyoon Lee
- Division of Molecular Embryology, DKFZ-ZMBH Alliance, Deutsches Krebsforschungszentrum (DKFZ), 69120, Heidelberg, Germany
| | - Celine Marie Camuto
- Division of Molecular Embryology, DKFZ-ZMBH Alliance, Deutsches Krebsforschungszentrum (DKFZ), 69120, Heidelberg, Germany
| | - Christof Niehrs
- Division of Molecular Embryology, DKFZ-ZMBH Alliance, Deutsches Krebsforschungszentrum (DKFZ), 69120, Heidelberg, Germany.
- Institute of Molecular Biology (IMB), 55128, Mainz, Germany.
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4
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Yue F, Ku AT, Stevens PD, Michalski MN, Jiang W, Tu J, Shi Z, Dou Y, Wang Y, Feng XH, Hostetter G, Wu X, Huang S, Shroyer NF, Zhang B, Williams BO, Liu Q, Lin X, Li Y. Loss of ZNRF3/RNF43 Unleashes EGFR in Cancer. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.10.574969. [PMID: 38260423 PMCID: PMC10802575 DOI: 10.1101/2024.01.10.574969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
ZNRF3 and RNF43 are closely related transmembrane E3 ubiquitin ligases with significant roles in development and cancer. Conventionally, their biological functions have been associated with regulating WNT signaling receptor ubiquitination and degradation. However, our proteogenomic studies have revealed EGFR as the most negatively correlated protein with ZNRF3/RNF43 mRNA levels in multiple human cancers. Through biochemical investigations, we demonstrate that ZNRF3/RNF43 interact with EGFR via their extracellular domains, leading to EGFR ubiquitination and subsequent degradation facilitated by the E3 ligase RING domain. Overexpression of ZNRF3 reduces EGFR levels and suppresses cancer cell growth in vitro and in vivo, whereas knockout of ZNRF3/RNF43 stimulates cell growth and tumorigenesis through upregulated EGFR signaling. Together, these data highlight ZNRF3 and RNF43 as novel E3 ubiquitin ligases of EGFR and establish the inactivation of ZNRF3/RNF43 as a driver of increased EGFR signaling, ultimately promoting cancer progression. This discovery establishes a connection between two fundamental signaling pathways, EGFR and WNT, at the level of cytoplasmic membrane receptor, uncovering a novel mechanism underlying the frequent co-activation of EGFR and WNT signaling in development and cancer.
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Affiliation(s)
- Fei Yue
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas 77030, USA
- Department of Medicine, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Amy T. Ku
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Payton D. Stevens
- Van Andel Institute, Department of Cell Biology, Grand Rapids, Michigan, 49503, USA
| | - Megan N. Michalski
- Van Andel Institute, Department of Cell Biology, Grand Rapids, Michigan, 49503, USA
| | - Weiyu Jiang
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Jianghua Tu
- Texas Therapeutics Institute and Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, Texas 77030, USA
| | - Zhongcheng Shi
- Advanced Technology Cores, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Yongchao Dou
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Yi Wang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing 102206, China
| | - Xin-Hua Feng
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Galen Hostetter
- Van Andel Institute, Core Technologies and Services, Grand Rapids, Michigan 49503, USA
| | - Xiangwei Wu
- Department of Clinical Cancer Prevention, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Shixia Huang
- Advanced Technology Cores, Baylor College of Medicine, Houston, Texas 77030, USA
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
- Department of Education, Innovation & Technology, Baylor College of Medicine, Houston, Texas 77030, USA
- Dan L. Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Noah F. Shroyer
- Department of Medicine, Baylor College of Medicine, Houston, Texas 77030, USA
- Dan L. Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Bing Zhang
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas 77030, USA
- Dan L. Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, Texas 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Bart O. Williams
- Van Andel Institute, Department of Cell Biology, Grand Rapids, Michigan, 49503, USA
- Van Andel Institute, Core Technologies and Services, Grand Rapids, Michigan 49503, USA
| | - Qingyun Liu
- Texas Therapeutics Institute and Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, Texas 77030, USA
| | - Xia Lin
- The First Affiliated Hospital of Zhejiang University, Hangzhou, Zhejiang 310003, China
| | - Yi Li
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas 77030, USA
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
- Dan L. Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, Texas 77030, USA
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas 77030, USA
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5
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Farnhammer F, Colozza G, Kim J. RNF43 and ZNRF3 in Wnt Signaling - A Master Regulator at the Membrane. Int J Stem Cells 2023; 16:376-384. [PMID: 37643759 PMCID: PMC10686798 DOI: 10.15283/ijsc23070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 07/10/2023] [Indexed: 08/31/2023] Open
Abstract
The Wnt β-catenin signaling pathway is a highly conserved mechanism that plays a critical role from embryonic development and adult stem cell homeostasis. However, dysregulation of the Wnt pathway has been implicated in various diseases, including cancer. Therefore, multiple layers of regulatory mechanisms tightly control the activation and suppression of the Wnt signal. The E3 ubiquitin ligases RNF43 and ZNRF3, which are known negative regulators of the Wnt pathway, are critical component of Wnt signaling regulation. These E3 ubiquitin ligases control Wnt signaling by targeting the Wnt receptor Frizzled to induce ubiquitination-mediated endo-lysosomal degradation, thus controlling the activation of the Wnt signaling pathway. We also discuss the regulatory mechanisms, interactors, and evolution of RNF43 and ZNRF3. This review article summarizes recent findings on RNF43 and ZNRF3 and their potential implications for the development of therapeutic strategies to target the Wnt signaling pathway in various diseases, including cancer.
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Affiliation(s)
- Fiona Farnhammer
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), Vienna, Austria
- Division of Oncology and Children’s Research Center, University Children’s Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Gabriele Colozza
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), Vienna, Austria
| | - Jihoon Kim
- Department of Medical and Biological Sciences, The Catholic University of Korea, Bucheon, Korea
- Center for Genome Engineering, Institute for Basic Science, Daejeon, Korea
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6
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Liu TT, Shi X, Hu HW, Chen JP, Jiang Q, Zhen YF, Cao C, Liu XW, Liu JG. Endothelial cell-derived RSPO3 activates Gαi1/3-Erk signaling and protects neurons from ischemia/reperfusion injury. Cell Death Dis 2023; 14:654. [PMID: 37805583 PMCID: PMC10560285 DOI: 10.1038/s41419-023-06176-2] [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: 03/22/2023] [Revised: 09/19/2023] [Accepted: 09/26/2023] [Indexed: 10/09/2023]
Abstract
The current study explores the potential function and the underlying mechanisms of endothelial cell-derived R-spondin 3 (RSPO3) neuroprotection against ischemia/reperfusion-induced neuronal cell injury. In both neuronal cells (Neuro-2a) and primary murine cortical neurons, pretreatment with RSPO3 ameliorated oxygen and glucose deprivation (OGD)/re-oxygenation (OGD/R)-induced neuronal cell death and oxidative injury. In neurons RSPO3 activated the Akt, Erk and β-Catenin signaling cascade, but only Erk inhibitors reversed RSPO3-induced neuroprotection against OGD/R. In mouse embryonic fibroblasts (MEFs) and neuronal cells, RSPO3-induced LGR4-Gab1-Gαi1/3 association was required for Erk activation, and either silencing or knockout of Gαi1 and Gαi3 abolished RSPO3-induced neuroprotection. In mice, middle cerebral artery occlusion (MCAO) increased RSPO3 expression and Erk activation in ischemic penumbra brain tissues. Endothelial knockdown or knockout of RSPO3 inhibited Erk activation in the ischemic penumbra brain tissues and increased MCAO-induced cerebral ischemic injury in mice. Conversely, endothelial overexpression of RSPO3 ameliorated MCAO-induced cerebral ischemic injury. We conclude that RSPO3 activates Gαi1/3-Erk signaling to protect neuronal cells from ischemia/reperfusion injury.
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Affiliation(s)
- Ting-Tao Liu
- Shandong University, Department of Neurology, Shandong Provincial Hospital, Jinan, China
- Department of Neurology, Shouguang Hospital of T.C.M, Shouguang, China
| | - Xin Shi
- Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Hong-Wei Hu
- Department of Neurosurgery, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Ju-Ping Chen
- Department of Neurology, Changshu Hospital of Traditional Chinese Medicine, Changshu, China
| | - Qin Jiang
- The Fourth School of Clinical Medicine, Nanjing Medical University, Nanjing, China
| | - Yun-Fang Zhen
- Department of Orthopedics, Children's hospital of Soochow University, Suzhou, China.
| | - Cong Cao
- Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, China.
| | - Xue-Wu Liu
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China.
| | - Jian-Gang Liu
- Department of Neurosurgery, The First Affiliated Hospital of Soochow University, Suzhou, China.
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7
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Wong C, Mulero MC, Barth EI, Wang K, Shang X, Tikle S, Rice C, Gately D, Howell SB. Exploiting the Receptor-Binding Domains of R-Spondin 1 to Target Leucine-Rich Repeat-Containin G-Coupled Protein Receptor 5-Expressing Stem Cells in Ovarian Cancer. J Pharmacol Exp Ther 2023; 385:95-105. [PMID: 36849411 PMCID: PMC10108443 DOI: 10.1124/jpet.122.001495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 02/06/2023] [Accepted: 02/08/2023] [Indexed: 03/01/2023] Open
Abstract
Leucine-rich repeat-containing G-protein-coupled receptor (LGR5) and LGR6 mark epithelial stem cells in normal tissues and tumors. They are expressed by stem cells in the ovarian surface and fallopian tube epithelia from which ovarian cancer arises. High-grade serous ovarian cancer is unique in expressing unusually high levels of LGR5 and LGR6 mRNA. R-spondins are the natural ligands for LGR5 and LGR6 to which they bind with nanomolar affinity. To target stem cells in ovarian cancer, we used the sortase reaction to site-specifically conjugate the potent cytotoxin monomethyl auristatin E (MMAE) via a protease sensitive linker to the two furin-like domains of RSPO1 (Fu1-Fu2) that mediate its binding to LGR5 and LGR6 and their co-receptors Zinc And Ring Finger 3 and Ring Finger Protein 43 via a protease-cleavable linker. An immunoglobulin Fc domain added to the N-terminal end served to dimerize the receptor-binding domains so that each molecule carries two MMAE. The resulting molecule, FcF2-MMAE, demonstrated: 1) selective LGR5-dependent low nanomolar cytotoxicity against ovarian cancer cells in vitro; 2) selectivity that was dependent on binding to both the LGR receptors and ubiquitin ligase co-receptors; 3) favorable stability and plasma pharmacokinetic properties when administered intravenously with an elimination half-life of 29.7 hours; 4) selective inhibition of LGR5-rich as opposed to isogenic LGR5-poor tumors in vivo; and, 5) therapeutic efficacy in three aggressive wild-type human ovarian cancer xenograft models. These results demonstrate the successful use of the Fu1-Fu2 domain of RSPO1 as a drug carrier and the ability of FcF2-MMAE to target cells in tumors that express stem cell markers. SIGNIFICANCE STATEMENT: FcF2-MMAE is a novel cancer therapeutic that exploits the high-affinity binding domains of RSPO1 to target monomethyl auristatin E to tumor stem cells that express LGR5. FcF2-MMAE has low nanomolar LGR5-dependent cytotoxicity in vitro, favorable pharmacokinetics, and differential efficacy in an isogenic LGR5-poor versus LGR5-rich ovarian cancer xenograft model when given on a weekly schedule.
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Affiliation(s)
- Clara Wong
- Moores Cancer Center and Department of Medicine, University of California, San Diego, 3855 Health Sciences Drive, Mail Code 0819, La Jolla, California
| | - Maria Carmen Mulero
- Moores Cancer Center and Department of Medicine, University of California, San Diego, 3855 Health Sciences Drive, Mail Code 0819, La Jolla, California
| | - Erika I Barth
- Moores Cancer Center and Department of Medicine, University of California, San Diego, 3855 Health Sciences Drive, Mail Code 0819, La Jolla, California
| | - Katherine Wang
- Moores Cancer Center and Department of Medicine, University of California, San Diego, 3855 Health Sciences Drive, Mail Code 0819, La Jolla, California
| | - Xiying Shang
- Moores Cancer Center and Department of Medicine, University of California, San Diego, 3855 Health Sciences Drive, Mail Code 0819, La Jolla, California
| | - Sanika Tikle
- Moores Cancer Center and Department of Medicine, University of California, San Diego, 3855 Health Sciences Drive, Mail Code 0819, La Jolla, California
| | - Catherine Rice
- Moores Cancer Center and Department of Medicine, University of California, San Diego, 3855 Health Sciences Drive, Mail Code 0819, La Jolla, California
| | - Dennis Gately
- Moores Cancer Center and Department of Medicine, University of California, San Diego, 3855 Health Sciences Drive, Mail Code 0819, La Jolla, California
| | - Stephen B Howell
- Moores Cancer Center and Department of Medicine, University of California, San Diego, 3855 Health Sciences Drive, Mail Code 0819, La Jolla, California
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8
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van Kerkhof P, Kralj T, Spanevello F, van Bloois L, Jordens I, van der Vaart J, Jamieson C, Merenda A, Mastrobattista E, Maurice MM. RSPO3 Furin domain-conjugated liposomes for selective drug delivery to LGR5-high cells. J Control Release 2023; 356:72-83. [PMID: 36813038 DOI: 10.1016/j.jconrel.2023.02.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 02/15/2023] [Accepted: 02/17/2023] [Indexed: 02/24/2023]
Abstract
The transmembrane receptor LGR5 potentiates Wnt/β-catenin signaling by binding both secreted R-spondin (RSPOs) and the Wnt tumor suppressors RNF43/ZNRF3, directing clearance of RNF43/ZNRF3 from the cell surface. Besides being widely used as a stem cell marker in various tissues, LGR5 is overexpressed in many types of malignancies, including colorectal cancer. Its expression characterizes a subpopulation of cancer cells that play a crucial role in tumor initiation, progression and cancer relapse, known as cancer stem cells (CSCs). For this reason, ongoing efforts are aimed at eradicating LGR5-positive CSCs. Here, we engineered liposomes decorated with different RSPO proteins to specifically detect and target LGR5-positive cells. Using fluorescence-loaded liposomes, we show that conjugation of full-length RSPO1 to the liposomal surface mediates aspecific, LGR5-independent cellular uptake, largely mediated by heparan sulfate proteoglycan binding. By contrast, liposomes decorated only with the Furin (FuFu) domains of RSPO3 are taken up by cells in a highly specific, LGR5-dependent manner. Moreover, encapsulating doxorubicin in FuFuRSPO3 liposomes allowed us to selectively inhibit the growth of LGR5-high cells. Thus, FuFuRSPO3-coated liposomes allow for the selective detection and ablation of LGR5-high cells, providing a potential drug delivery system for LGR5-targeted anti-cancer strategies.
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Affiliation(s)
- Peter van Kerkhof
- Oncode Institute and Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Tomica Kralj
- Oncode Institute and Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Francesca Spanevello
- Oncode Institute and Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Louis van Bloois
- Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Utrecht, the Netherlands
| | - Ingrid Jordens
- Oncode Institute and Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Jelte van der Vaart
- Oncode Institute and Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Cara Jamieson
- Oncode Institute and Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Alessandra Merenda
- Oncode Institute and Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Enrico Mastrobattista
- Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Utrecht, the Netherlands.
| | - Madelon M Maurice
- Oncode Institute and Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht, the Netherlands.
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9
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Yu K, Yang J, Xie S, Ma B, Wang L. A new Cu(II)-containing coordination polymer: protective effect and mechanism exploration on elderly osteoporotic hip fractures via regulating the wnt signaling pathway. Mol Divers 2022; 26:1151-1159. [PMID: 34106417 DOI: 10.1007/s11030-021-10241-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 05/28/2021] [Indexed: 11/28/2022]
Abstract
Elderly osteoporosis hip fracture has drawn the attention of the researcher. The coordination polymer was now widely used in clinic because their multiple structures and biological activities. In this present research, the new coordination polymer was designed and synthesized and their application values on elderly osteoporosis hip were evaluated. The reaction between Cu(II) salt and 4,4'-(1H-1,2,4-triazol-1-yl)methylene-bis(benzoic acid) (H2tzmb), an aromatase inhibitor letrozole derivative with the aid of the organic linker 4,4-bipyridine (4,4'-bpy) affords a new coordination polymer based on Cu(II) ions as nodes of {[Cu2(tzmb)2(4,4'-bpy) (μ2-H2O)2(DMA) (H2O)2]·10DMA}n (1). The complex 1 gained is totally investigated with the powder X-ray diffraction study, thermogravimetric analyses, the diffraction of single-crystal X-ray, elemental analysis as well as the Fourier transform infrared spectrometer spectra. The osteogenic differentiation of mesenchymal stem cell was measured with the western blotting assay through determining the Runx2 expression. The wnt signaling pathway relative expression in mesenchymal stem cell was detected through the determination of real-time RT-PCR. The cytotoxicity of the compound on the mesenchymal stem cell was determined with CCK-8 assay. The result of single-crystal X-ray diffraction reflects that the complex 1 has crystallized in space group R-3c of trigonal system and exhibits a three-dimensional skeleton architecture on the bases of the SBUs {Cu(tzmb)(μ2-H2O)}n. The western blotting assay results revealed that this compound could significantly promote the osteogenic differentiation of mesenchymal stem cell. Besides, the activation of wnt signaling pathway in mesenchymal stem cell was also increased by the compound exposure. Finally, it can be summed up that this compound has excellent application values on the elderly osteoporotic hip fractures treatment by increasing the activation of wnt signaling pathway in mesenchymal stem cell. The results of the CCK-8 assay indicated that the compound has no cytotoxicity on the mesenchymal stem cell. The molecular docking simulation results have identified that only the carboxyl group on the Cu complex exhibits the activity for the hydrogen bond formation, however, the pyridine ring does not have such activity, instead, the pyridine ring only acts as the ligand that binds to the Cu ion. This Cu(II) coordination polymer has excellent application values on the elderly osteoporotic hip fractures treatment by increasing the activation of wnt signaling pathway in mesenchymal stem cell.
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Affiliation(s)
- Kai Yu
- Department of Orthopedics, Tianjin Fifth Central Hospital, Tianjin, China
| | - Jie Yang
- Department of Orthopedics, Tianjin Fifth Central Hospital, Tianjin, China
| | - Shangding Xie
- Department of Orthopedics, Tianjin Fifth Central Hospital, Tianjin, China.
| | - Bingqin Ma
- Department of Medicine, Soochow University, Changzhou, Jiangsu, China
| | - Liangzhi Wang
- Department of Medicine, Soochow University, Changzhou, Jiangsu, China
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10
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Lee H, Sun R, Niehrs C. Uncoupling the BMP receptor antagonist function from the WNT agonist function of R-spondin 2 using the inhibitory peptide dendrimer RW d. J Biol Chem 2022; 298:101586. [PMID: 35032551 PMCID: PMC8842081 DOI: 10.1016/j.jbc.2022.101586] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 01/04/2022] [Accepted: 01/05/2022] [Indexed: 11/28/2022] Open
Abstract
Signaling by bone morphogenetic proteins (BMPs) plays pivotal roles in embryogenesis, adult tissue homeostasis, and disease. Recent studies revealed that the well-established WNT agonist R-spondin 2 (RSPO2) is also a BMP receptor (BMP receptor type 1A) antagonist, with roles in early Xenopus embryogenesis and human acute myeloid leukemia (AML). To uncouple the BMP antagonist function from the WNT agonist function and to promote development of AML therapeutics, here we identified a 10-mer peptide (RW) derived from the thrombospondin 1 domain of RSPO2, which specifically prevents binding between RSPO2 and BMP receptor type 1A without altering WNT signaling. We also show that a corresponding RW dendrimer (RWd) exhibiting improved half-life relieves inhibition of BMP receptor signaling by RSPO2 in human AML cells, reduces cell growth, and induces differentiation. Moreover, microinjection of RWd in Xenopus embryos ventralizes the dorsoventral embryonic patterning by upregulating BMP signaling without affecting WNT signaling. Our study corroborates the function of RSPO2 as a BMP receptor antagonist and provides a proof of concept for pharmacologically uncoupling BMP antagonist from WNT agonist functions of RSPO2 using the inhibitor peptide RWd with enhanced target selectivity and limited side effects.
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Affiliation(s)
- Hyeyoon Lee
- Division of Molecular Embryology, DKFZ-ZMBH Alliance, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
| | - Rui Sun
- Division of Molecular Embryology, DKFZ-ZMBH Alliance, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
| | - Christof Niehrs
- Division of Molecular Embryology, DKFZ-ZMBH Alliance, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany; Institute of Molecular Biology (IMB), Mainz, Germany.
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11
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Lebensohn AM, Bazan JF, Rohatgi R. Receptor control by membrane-tethered ubiquitin ligases in development and tissue homeostasis. Curr Top Dev Biol 2022; 150:25-89. [PMID: 35817504 DOI: 10.1016/bs.ctdb.2022.03.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Paracrine cell-cell communication is central to all developmental processes, ranging from cell diversification to patterning and morphogenesis. Precise calibration of signaling strength is essential for the fidelity of tissue formation during embryogenesis and tissue maintenance in adults. Membrane-tethered ubiquitin ligases can control the sensitivity of target cells to secreted ligands by regulating the abundance of signaling receptors at the cell surface. We discuss two examples of this emerging concept in signaling: (1) the transmembrane ubiquitin ligases ZNRF3 and RNF43 that regulate WNT and bone morphogenetic protein receptor abundance in response to R-spondin ligands and (2) the membrane-recruited ubiquitin ligase MGRN1 that controls Hedgehog and melanocortin receptor abundance. We focus on the mechanistic logic of these systems, illustrated by structural and protein interaction models enabled by AlphaFold. We suggest that membrane-tethered ubiquitin ligases play a widespread role in remodeling the cell surface proteome to control responses to extracellular ligands in diverse biological processes.
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12
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Radaszkiewicz T, Nosková M, Gömöryová K, Vondálová Blanářová O, Radaszkiewicz KA, Picková M, Víchová R, Gybeľ T, Kaiser K, Demková L, Kučerová L, Bárta T, Potěšil D, Zdráhal Z, Souček K, Bryja V. RNF43 inhibits WNT5A-driven signaling and suppresses melanoma invasion and resistance to the targeted therapy. eLife 2021; 10:65759. [PMID: 34702444 PMCID: PMC8550759 DOI: 10.7554/elife.65759] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 09/28/2021] [Indexed: 12/30/2022] Open
Abstract
RNF43 is an E3 ubiquitin ligase and known negative regulator of WNT/β-catenin signaling. We demonstrate that RNF43 is also a regulator of noncanonical WNT5A-induced signaling in human cells. Analysis of the RNF43 interactome using BioID and immunoprecipitation showed that RNF43 can interact with the core receptor complex components dedicated to the noncanonical Wnt pathway such as ROR1, ROR2, VANGL1, and VANGL2. RNF43 triggers VANGL2 ubiquitination and proteasomal degradation and clathrin-dependent internalization of ROR1 receptor and inhibits ROR2 activation. These activities of RNF43 are physiologically relevant and block pro-metastatic WNT5A signaling in melanoma. RNF43 inhibits responses to WNT5A, which results in the suppression of invasive properties of melanoma cells. Furthermore, RNF43 prevented WNT5A-assisted development of resistance to BRAF V600E and MEK inhibitors. Next, RNF43 acted as melanoma suppressor and improved response to targeted therapies in vivo. In line with these findings, RNF43 expression decreases during melanoma progression and RNF43-low patients have a worse prognosis. We conclude that RNF43 is a newly discovered negative regulator of WNT5A-mediated biological responses that desensitizes cells to WNT5A.
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Affiliation(s)
- Tomasz Radaszkiewicz
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Michaela Nosková
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Kristína Gömöryová
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Olga Vondálová Blanářová
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | | | - Markéta Picková
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic.,Department of Cytokinetics, Institute of Biophysics CAS, Brno, Czech Republic.,International Clinical Research Center FNUSA-ICRC, Brno, Czech Republic
| | - Ráchel Víchová
- Department of Cytokinetics, Institute of Biophysics CAS, Brno, Czech Republic
| | - Tomáš Gybeľ
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Karol Kaiser
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Lucia Demková
- Laboratory of Molecular Oncology, Cancer Research Institute, Biomedical Research Center of the Slovak Academy of Sciences, Bratislava, Slovakia
| | - Lucia Kučerová
- Laboratory of Molecular Oncology, Cancer Research Institute, Biomedical Research Center of the Slovak Academy of Sciences, Bratislava, Slovakia
| | - Tomáš Bárta
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic.,Department of Histology and Embryology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - David Potěšil
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Zbyněk Zdráhal
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Karel Souček
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic.,Department of Cytokinetics, Institute of Biophysics CAS, Brno, Czech Republic.,International Clinical Research Center FNUSA-ICRC, Brno, Czech Republic
| | - Vítězslav Bryja
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic.,Department of Cytokinetics, Institute of Biophysics CAS, Brno, Czech Republic
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13
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Peng WC, Kraaier LJ, Kluiver TA. Hepatocyte organoids and cell transplantation: What the future holds. Exp Mol Med 2021; 53:1512-1528. [PMID: 34663941 PMCID: PMC8568948 DOI: 10.1038/s12276-021-00579-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/11/2021] [Accepted: 01/14/2021] [Indexed: 12/29/2022] Open
Abstract
Historically, primary hepatocytes have been difficult to expand or maintain in vitro. In this review, we will focus on recent advances in establishing hepatocyte organoids and their potential applications in regenerative medicine. First, we provide a background on the renewal of hepatocytes in the homeostatic as well as the injured liver. Next, we describe strategies for establishing primary hepatocyte organoids derived from either adult or fetal liver based on insights from signaling pathways regulating hepatocyte renewal in vivo. The characteristics of these organoids will be described herein. Notably, hepatocyte organoids can adopt either a proliferative or a metabolic state, depending on the culture conditions. Furthermore, the metabolic gene expression profile can be modulated based on the principles that govern liver zonation. Finally, we discuss the suitability of cell replacement therapy to treat different types of liver diseases and the current state of cell transplantation of in vitro-expanded hepatocytes in mouse models. In addition, we provide insights into how the regenerative microenvironment in the injured host liver may facilitate donor hepatocyte repopulation. In summary, transplantation of in vitro-expanded hepatocytes holds great potential for large-scale clinical application to treat liver diseases.
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Affiliation(s)
- Weng Chuan Peng
- Princess Máxima Center for Pediatric Oncology, Heidelberglaan 25, 3584 CS, Utrecht, The Netherlands.
| | - Lianne J Kraaier
- Princess Máxima Center for Pediatric Oncology, Heidelberglaan 25, 3584 CS, Utrecht, The Netherlands
| | - Thomas A Kluiver
- Princess Máxima Center for Pediatric Oncology, Heidelberglaan 25, 3584 CS, Utrecht, The Netherlands
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14
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Hiremath IS, Goel A, Warrier S, Kumar AP, Sethi G, Garg M. The multidimensional role of the Wnt/β-catenin signaling pathway in human malignancies. J Cell Physiol 2021; 237:199-238. [PMID: 34431086 DOI: 10.1002/jcp.30561] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 07/28/2021] [Accepted: 08/09/2021] [Indexed: 02/06/2023]
Abstract
Several signaling pathways have been identified as important for developmental processes. One of such important cascades is the Wnt/β-catenin signaling pathway, which can regulate various physiological processes such as embryonic development, tissue homeostasis, and tissue regeneration; while its dysregulation is implicated in several pathological conditions especially cancers. Interestingly, deregulation of the Wnt/β-catenin pathway has been reported to be closely associated with initiation, progression, metastasis, maintenance of cancer stem cells, and drug resistance in human malignancies. Moreover, several genetic and experimental models support the inhibition of the Wnt/β-catenin pathway to answer the key issues related to cancer development. The present review focuses on different regulators of Wnt pathway and how distinct mutations, deletion, and amplification in these regulators could possibly play an essential role in the development of several cancers such as colorectal, melanoma, breast, lung, and leukemia. Additionally, we also provide insights on diverse classes of inhibitors of the Wnt/β-catenin pathway, which are currently in preclinical and clinical trial against different cancers.
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Affiliation(s)
- Ishita S Hiremath
- Department of Bioengineering, Birla Institute of Technology, Mesra, Ranchi, Jharkhand, India
| | - Arul Goel
- La Canada High School, La Canada Flintridge, California, USA
| | - Sudha Warrier
- Division of Cancer Stem Cells and Cardiovascular Regeneration, Manipal Institute of Regenerative Medicine, Manipal Academy of Higher Education (MAHE), Bangalore, Karnataka, India.,Cuor Stem Cellutions Pvt Ltd, Manipal Institute of Regenerative Medicine, Manipal Academy of Higher Education (MAHE), Bangalore, Karnataka, India
| | - Alan Prem Kumar
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Cancer Science Institute of Singapore and Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,NUS Centre for Cancer Research, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Gautam Sethi
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,NUS Centre for Cancer Research, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Manoj Garg
- Amity Institute of Biotechnology, Amity University, Manesar, Haryana, India
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15
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The structural biology of canonical Wnt signalling. Biochem Soc Trans 2021; 48:1765-1780. [PMID: 32725184 PMCID: PMC7458405 DOI: 10.1042/bst20200243] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/04/2020] [Accepted: 07/07/2020] [Indexed: 12/17/2022]
Abstract
The Wnt signalling pathways are of great importance in embryonic development and oncogenesis. Canonical and non-canonical Wnt signalling pathways are known, with the canonical (or β-catenin dependent) pathway being perhaps the best studied of these. While structural knowledge of proteins and interactions involved in canonical Wnt signalling has accumulated over the past 20 years, the pace of discovery has increased in recent years, with the structures of several key proteins and assemblies in the pathway being released. In this review, we provide a brief overview of canonical Wnt signalling, followed by a comprehensive overview of currently available X-ray, NMR and cryoEM data elaborating the structures of proteins and interactions involved in canonical Wnt signalling. While the volume of structures available is considerable, numerous gaps in knowledge remain, particularly a comprehensive understanding of the assembly of large multiprotein complexes mediating key aspects of pathway, as well as understanding the structure and activation of membrane receptors in the pathway. Nonetheless, the presently available data affords considerable opportunities for structure-based drug design efforts targeting canonical Wnt signalling.
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16
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The Role of LGR4 (GPR48) in Normal and Cancer Processes. Int J Mol Sci 2021; 22:ijms22094690. [PMID: 33946652 PMCID: PMC8125670 DOI: 10.3390/ijms22094690] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 04/23/2021] [Accepted: 04/23/2021] [Indexed: 12/13/2022] Open
Abstract
Leucine-rich repeats containing G protein-coupled receptor 4 (LGR4) is a receptor that belongs to the superfamily of G protein-coupled receptors that can be activated by R-spondins (RSPOs), Norrin, circLGR4, and the ligand of the receptor activator of nuclear factor kappa-B (RANKL) ligands to regulate signaling pathways in normal and pathological processes. LGR4 is widely expressed in different tissues where it has multiple functions such as tissue development and maintenance. LGR4 mainly acts through the Wnt/β-catenin pathway to regulate proliferation, survival, and differentiation. In cancer, LGR4 participates in tumor progression, invasion, and metastasis. Furthermore, recent evidence reveals that LGR4 is essential for the regulation of the cancer stem cell population by controlling self-renewal and regulating stem cell properties. This review summarizes the function of LGR4 and its ligands in normal and malignant processes.
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17
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Park S, Wu L, Tu J, Yu W, Toh Y, Carmon KS, Liu QJ. Unlike LGR4, LGR5 potentiates Wnt-β-catenin signaling without sequestering E3 ligases. Sci Signal 2020; 13:13/660/eaaz4051. [PMID: 33262293 DOI: 10.1126/scisignal.aaz4051] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
LGR4 and LGR5 encode two homologous receptors with critical, yet distinct, roles in organ development and adult stem cell survival. Both receptors are coexpressed in intestinal crypt stem cells, bind to R-spondins (RSPOs) with high affinity, and potentiate Wnt-β-catenin signaling, presumably by the same mechanism: forming RSPO-bridged complexes with the E3 ligases RNF43 and ZNRF3 to inhibit ubiquitylation of Wnt receptors. However, direct evidence for RSPO-bound, full-length LGR5 interacting with these E3 ligases in whole cells has not been reported, and only LGR4 is essential for the self-renewal of intestinal stem cells. Here, we examined the mechanisms of action of LGR4 and LGR5 in parallel using coimmunoprecipitation, proximity ligation, competition binding, and time-resolved FRET assays in whole cells. Full-length LGR4 formed a tight complex with ZNRF3 and RNF43 even without RSPO, whereas LGR5 did not interact with either E3 ligase with or without RSPO. Domain-swapping experiments with LGR4 and LGR5 revealed that the seven-transmembrane domain of LGR4 conferred interaction with the E3 ligases. Native LGR4 and LGR5 existed as dimers on the cell surface, and LGR5 interacted with both FZD and LRP6 of the Wnt signalosome to enhance LRP6 phosphorylation and potentiate Wnt-β-catenin signaling. These findings provide a molecular basis for the weaker activity of LGR5 in the potentiation of Wnt signaling that may underlie the distinct roles of LGR4 and LGR5 in organ development, as well as the self-renewal and fitness of adult stem cells.
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Affiliation(s)
- Soohyun Park
- Center for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Ling Wu
- Center for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Jianghua Tu
- Center for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Wangsheng Yu
- Center for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Yukimatsu Toh
- Center for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Kendra S Carmon
- Center for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Qingyun J Liu
- Center for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
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18
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Spit M, Fenderico N, Jordens I, Radaszkiewicz T, Lindeboom RGH, Bugter JM, Cristobal A, Ootes L, van Osch M, Janssen E, Boonekamp KE, Hanakova K, Potesil D, Zdrahal Z, Boj SF, Medema JP, Bryja V, Koo B, Vermeulen M, Maurice MM. RNF43 truncations trap CK1 to drive niche-independent self-renewal in cancer. EMBO J 2020; 39:e103932. [PMID: 32965059 PMCID: PMC7503102 DOI: 10.15252/embj.2019103932] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 06/19/2020] [Accepted: 06/22/2020] [Indexed: 12/26/2022] Open
Abstract
Wnt/β-catenin signaling is a primary pathway for stem cell maintenance during tissue renewal and a frequent target for mutations in cancer. Impaired Wnt receptor endocytosis due to loss of the ubiquitin ligase RNF43 gives rise to Wnt-hypersensitive tumors that are susceptible to anti-Wnt-based therapy. Contrary to this paradigm, we identify a class of RNF43 truncating cancer mutations that induce β-catenin-mediated transcription, despite exhibiting retained Wnt receptor downregulation. These mutations interfere with a ubiquitin-independent suppressor role of the RNF43 cytosolic tail that involves Casein kinase 1 (CK1) binding and phosphorylation. Mechanistically, truncated RNF43 variants trap CK1 at the plasma membrane, thereby preventing β-catenin turnover and propelling ligand-independent target gene transcription. Gene editing of human colon stem cells shows that RNF43 truncations cooperate with p53 loss to drive a niche-independent program for self-renewal and proliferation. Moreover, these RNF43 variants confer decreased sensitivity to anti-Wnt-based therapy. Our data demonstrate the relevance of studying patient-derived mutations for understanding disease mechanisms and improved applications of precision medicine.
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Affiliation(s)
- Maureen Spit
- Department of Cell Biology and Oncode InstituteCenter for Molecular MedicineUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Nicola Fenderico
- Department of Cell Biology and Oncode InstituteCenter for Molecular MedicineUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Ingrid Jordens
- Department of Cell Biology and Oncode InstituteCenter for Molecular MedicineUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Tomasz Radaszkiewicz
- Department of Experimental BiologyFaculty of ScienceMasaryk UniversityBrnoCzech Republic
| | - Rik GH Lindeboom
- Department of Molecular Biology and Oncode InstituteFaculty of ScienceRadboud Institute for Molecular Life SciencesRadboud University NijmegenNijmegenThe Netherlands
| | - Jeroen M Bugter
- Department of Cell Biology and Oncode InstituteCenter for Molecular MedicineUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Alba Cristobal
- Department of Cell Biology and Oncode InstituteCenter for Molecular MedicineUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Lars Ootes
- Department of Cell Biology and Oncode InstituteCenter for Molecular MedicineUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Max van Osch
- Department of Cell Biology and Oncode InstituteCenter for Molecular MedicineUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Eline Janssen
- Department of Cell Biology and Oncode InstituteCenter for Molecular MedicineUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Kim E Boonekamp
- Department of Cell Biology and Oncode InstituteCenter for Molecular MedicineUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Katerina Hanakova
- Central European Institute of TechnologyMasaryk UniversityBrnoCzech Republic
| | - David Potesil
- Central European Institute of TechnologyMasaryk UniversityBrnoCzech Republic
| | - Zbynek Zdrahal
- Central European Institute of TechnologyMasaryk UniversityBrnoCzech Republic
| | - Sylvia F Boj
- Hubrecht Organoid TechnologyUtrechtThe Netherlands
| | - Jan Paul Medema
- Laboratory for Experimental Oncology and Radiobiology and Oncode InstituteCenter for Experimental and Molecular MedicineAmsterdam UMCCancer Center AmsterdamUniversity of AmsterdamAmsterdamThe Netherlands
| | - Vitezslav Bryja
- Department of Experimental BiologyFaculty of ScienceMasaryk UniversityBrnoCzech Republic
| | - Bon‐Kyoung Koo
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA)Vienna BioCenter (VBC)ViennaAustria
| | - Michiel Vermeulen
- Department of Molecular Biology and Oncode InstituteFaculty of ScienceRadboud Institute for Molecular Life SciencesRadboud University NijmegenNijmegenThe Netherlands
| | - Madelon M Maurice
- Department of Cell Biology and Oncode InstituteCenter for Molecular MedicineUniversity Medical Center UtrechtUtrechtThe Netherlands
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19
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Abstract
R-spondin (RSPO) proteins amplify Wnt signaling and stimulate regeneration in a variety of tissues. To repair tissue in a tissue-specific manner, tissue-targeted RSPO mimetic molecules are desired. Here, we mutated RSPO (RSPO2 F105R/F109A) to eliminate LGR binding while preserving ZNRF3/RNF43 binding and targeted the mutated RSPO to a liver specific receptor, ASGR1. The resulting bi-specific molecule (αASGR1-RSPO2-RA) enhanced Wnt signaling effectively in vitro, and its activity was limited to ASGR1 expressing cells. Systemic administration of αASGR1-RSPO2-RA in mice specifically upregulated Wnt target genes and stimulated cell proliferation in liver but not intestine (which is more responsive to non-targeted RSPO2) in healthy mice, and improved liver function in diseased mice. These results not only suggest that a tissue-specific RSPO mimetic protein can stimulate regeneration in a cell-specific manner, but also provide a blueprint of how a tissue-specific molecule might be constructed for applications in a broader context.
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20
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Radaszkiewicz T, Bryja V. Protease associated domain of RNF43 is not necessary for the suppression of Wnt/β-catenin signaling in human cells. Cell Commun Signal 2020; 18:91. [PMID: 32527265 PMCID: PMC7291719 DOI: 10.1186/s12964-020-00559-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 03/23/2020] [Indexed: 12/19/2022] Open
Abstract
Background RNF43 and its homolog ZNRF3 are transmembrane E3 ubiquitin ligases frequently mutated in many human cancer types. Their main role relays on the inhibition of canonical Wnt signaling by the negative regulation of frizzled receptors and LRP5/6 co-receptors levels at the plasma membrane. Intracellular RING domains of RNF43/ZNRF3 mediate the key enzymatic activity of these proteins, but the function of the extracellular Protease Associated (PA) fold in the inhibition of Wnt/β-catenin pathway is controversial up-to date, apart from the interaction with secreted antagonists R-spondin family proteins shown by the crystallographic studies. Methods In our research we utilised cell-based approaches to study the role of RNF43 lacking PA domain in the canonical Wnt signalling pathway transduction. We developed controlled overexpression (TetON) and CRISPR/Cas9 mediated knock-out models in human cells. Results RNF43ΔPA mutant activity impedes canonical Wnt pathway, as manifested by the reduced phosphorylation of LRP6, DVL2 and DVL3 and by the decreased β-catenin-dependent gene expression. Finally, rescue experiments in the CRISPR/Cas9 derived RNF43/ZNRF3 double knock-out cell lines showed that RNFΔPA overexpression is enough to inhibit activation of LRP6 and β-catenin activity as shown by the Western blot and Top flash dual luciferase assays. Moreover, RNF43 variant without PA domain was not sensitive to the R-spondin1 treatment. Conclusion Taken together, our results help to understand better the mode of RNF43 tumor suppressor action and solve some discrepancies present in the field. Video Abstract
Graphical Abstract ![]()
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Affiliation(s)
- Tomasz Radaszkiewicz
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Vítězslav Bryja
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic. .,Department of Cytokinetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, Czech Republic.
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21
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Wang L, Deng K, Gong L, Zhou L, Sayed S, Li H, Sun Q, Su Z, Wang Z, Liu S, Zhu H, Song J, Lu D. Chlorquinaldol targets the β-catenin and T-cell factor 4 complex and exerts anti-colorectal cancer activity. Pharmacol Res 2020; 159:104955. [PMID: 32485279 DOI: 10.1016/j.phrs.2020.104955] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 05/06/2020] [Accepted: 05/21/2020] [Indexed: 02/07/2023]
Abstract
Aberrant activation of Wnt signaling plays a critical role in the initiation and progression of colorectal cancer (CRC). Chlorquinaldol (CQD) is a topical antimicrobial agent used to treat skin infections. Little is known about the anticancer activity of CQD and its underlying mechanisms. In this study, CQD was demonstrated to inhibit Wnt/β-catenin signaling through targeting the downstream part of this pathway. The results showed that CQD could inhibit the acetylation of β-catenin and disrupt the interaction of β-catenin with T-cell factor 4 (TCF4), leading to reduced binding of β-catenin to the promoters of Wnt target genes and downregulation of the expression of these target genes. Moreover, treatment with CQD suppressed the proliferation, migration, invasion and stemness of CRC cells. In APCmin/+ mice and CRC cell xenografts, administration of CQD suppressed tumor growth and the expression of Wnt target genes c-Myc and Leucine-rich G protein-coupled receptor-5 (LGR5). These results strongly suggest that CQD may be a promising therapeutic agent in the treatment of CRC.
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Affiliation(s)
- Ling Wang
- Guangdong Key Laboratory for Genome Stability & Disease Prevention, Cancer Research Center, Department of Pharmacology, Shenzhen University Health Science Center, Shenzhen, Guangdong, 518060, China
| | - Ke Deng
- Guangdong Key Laboratory for Genome Stability & Disease Prevention, Cancer Research Center, Department of Pharmacology, Shenzhen University Health Science Center, Shenzhen, Guangdong, 518060, China
| | - Liang Gong
- Guangdong Key Laboratory for Genome Stability & Disease Prevention, Cancer Research Center, Department of Pharmacology, Shenzhen University Health Science Center, Shenzhen, Guangdong, 518060, China
| | - Liang Zhou
- Guangdong Key Laboratory for Genome Stability & Disease Prevention, Cancer Research Center, Department of Pharmacology, Shenzhen University Health Science Center, Shenzhen, Guangdong, 518060, China
| | - Sapna Sayed
- Guangdong Key Laboratory for Genome Stability & Disease Prevention, Cancer Research Center, Department of Pharmacology, Shenzhen University Health Science Center, Shenzhen, Guangdong, 518060, China
| | - Huan Li
- Guangdong Key Laboratory for Genome Stability & Disease Prevention, Cancer Research Center, Department of Pharmacology, Shenzhen University Health Science Center, Shenzhen, Guangdong, 518060, China
| | - Qi Sun
- Guangdong Key Laboratory for Genome Stability & Disease Prevention, Cancer Research Center, Department of Pharmacology, Shenzhen University Health Science Center, Shenzhen, Guangdong, 518060, China
| | - Zijie Su
- Guangdong Key Laboratory for Genome Stability & Disease Prevention, Cancer Research Center, Department of Pharmacology, Shenzhen University Health Science Center, Shenzhen, Guangdong, 518060, China
| | - Zhongyuan Wang
- Guangdong Key Laboratory for Genome Stability & Disease Prevention, Cancer Research Center, Department of Pharmacology, Shenzhen University Health Science Center, Shenzhen, Guangdong, 518060, China
| | - Shanshan Liu
- Guangdong Key Laboratory for Genome Stability & Disease Prevention, Cancer Research Center, Department of Pharmacology, Shenzhen University Health Science Center, Shenzhen, Guangdong, 518060, China
| | - Huifang Zhu
- Guangdong Key Laboratory for Genome Stability & Disease Prevention, Cancer Research Center, Department of Pharmacology, Shenzhen University Health Science Center, Shenzhen, Guangdong, 518060, China
| | - Jiaxing Song
- Guangdong Key Laboratory for Genome Stability & Disease Prevention, Cancer Research Center, Department of Pharmacology, Shenzhen University Health Science Center, Shenzhen, Guangdong, 518060, China.
| | - Desheng Lu
- Guangdong Key Laboratory for Genome Stability & Disease Prevention, Cancer Research Center, Department of Pharmacology, Shenzhen University Health Science Center, Shenzhen, Guangdong, 518060, China.
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22
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Dubey R, van Kerkhof P, Jordens I, Malinauskas T, Pusapati GV, McKenna JK, Li D, Carette JE, Ho M, Siebold C, Maurice M, Lebensohn AM, Rohatgi R. R-spondins engage heparan sulfate proteoglycans to potentiate WNT signaling. eLife 2020; 9:e54469. [PMID: 32432544 PMCID: PMC7239654 DOI: 10.7554/elife.54469] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/25/2020] [Indexed: 12/17/2022] Open
Abstract
R-spondins (RSPOs) amplify WNT signaling during development and regenerative responses. We previously demonstrated that RSPOs 2 and 3 potentiate WNT/β-catenin signaling in cells lacking leucine-rich repeat-containing G-protein coupled receptors (LGRs) 4, 5 and 6 (Lebensohn and Rohatgi, 2018). We now show that heparan sulfate proteoglycans (HSPGs) act as alternative co-receptors for RSPO3 using a combination of ligand mutagenesis and ligand engineering. Mutations in RSPO3 residues predicted to contact HSPGs impair its signaling capacity. Conversely, the HSPG-binding domains of RSPO3 can be entirely replaced with an antibody that recognizes heparan sulfate (HS) chains attached to multiple HSPGs without diminishing WNT-potentiating activity in cultured cells and intestinal organoids. A genome-wide screen for mediators of RSPO3 signaling in cells lacking LGRs 4, 5 and 6 failed to reveal other receptors. We conclude that HSPGs are RSPO co-receptors that potentiate WNT signaling in the presence and absence of LGRs.
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Affiliation(s)
- Ramin Dubey
- Departments of Biochemistry and Medicine, Stanford University School of MedicineStanfordUnited States
| | - Peter van Kerkhof
- Department of Cell Biology and Oncode Institute, Centre for Molecular Medicine, University Medical Centre UtrechtUtrechtNetherlands
| | - Ingrid Jordens
- Department of Cell Biology and Oncode Institute, Centre for Molecular Medicine, University Medical Centre UtrechtUtrechtNetherlands
| | - Tomas Malinauskas
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of OxfordOxfordUnited Kingdom
| | - Ganesh V Pusapati
- Departments of Biochemistry and Medicine, Stanford University School of MedicineStanfordUnited States
| | - Joseph K McKenna
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of HealthBethesdaUnited States
| | - Dan Li
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of HealthBethesdaUnited States
| | - Jan E Carette
- Department of Microbiology and Immunology, Stanford University School of MedicineStanfordUnited States
| | - Mitchell Ho
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of HealthBethesdaUnited States
| | - Christian Siebold
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of OxfordOxfordUnited Kingdom
| | - Madelon Maurice
- Department of Cell Biology and Oncode Institute, Centre for Molecular Medicine, University Medical Centre UtrechtUtrechtNetherlands
| | - Andres M Lebensohn
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of HealthBethesdaUnited States
| | - Rajat Rohatgi
- Departments of Biochemistry and Medicine, Stanford University School of MedicineStanfordUnited States
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23
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Jarman EJ, Boulter L. Targeting the Wnt signaling pathway: the challenge of reducing scarring without affecting repair. Expert Opin Investig Drugs 2020; 29:179-190. [DOI: 10.1080/13543784.2020.1718105] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Edward J. Jarman
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, Edinburgh, UK
| | - Luke Boulter
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, Edinburgh, UK
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24
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Dzobo K, Thomford NE, Senthebane DA. Targeting the Versatile Wnt/β-Catenin Pathway in Cancer Biology and Therapeutics: From Concept to Actionable Strategy. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2019; 23:517-538. [PMID: 31613700 DOI: 10.1089/omi.2019.0147] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
This expert review offers a critical synthesis of the latest insights and approaches at targeting the Wnt/β-catenin pathway in various cancers such as colorectal cancer, melanoma, leukemia, and breast and lung cancers. Notably, from organogenesis to cancer, the Wnt/β-catenin signaling displays varied and highly versatile biological functions in animals, with virtually all tissues requiring the Wnt/β-catenin signaling in one way or the other. Aberrant expression of the members of the Wnt/β-catenin has been implicated in many pathological conditions, particularly in human cancers. Mutations in the Wnt/β-catenin pathway genes have been noted in diverse cancers. Biochemical and genetic data support the idea that inhibition of Wnt/β-catenin signaling is beneficial in cancer therapeutics. The interaction of this important pathway with other signaling systems is also noteworthy, but remains as an area for further research and discovery. In addition, formation of different complexes by components of the Wnt/β-catenin pathway and the precise roles of these complexes in the cytoplasmic milieu are yet to be fully elucidated. This article highlights the latest medical technologies in imaging, single-cell omics, use of artificial intelligence (e.g., machine learning techniques), genome sequencing, quantum computing, molecular docking, and computational softwares in modeling interactions between molecules and predicting protein-protein and compound-protein interactions pertinent to the biology and therapeutic value of the Wnt/β-catenin signaling pathway. We discuss these emerging technologies in relationship to what is currently needed to move from concept to actionable strategies in translating the Wnt/β-catenin laboratory discoveries to Wnt-targeted cancer therapies and diagnostics in the clinic.
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Affiliation(s)
- Kevin Dzobo
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Cape Town, South Africa.,Division of Medical Biochemistry and Institute of Infectious Disease and Molecular Medicine, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Nicholas Ekow Thomford
- Pharmacogenetics Research Group, Division of Human Genetics, Department of Pathology and Institute of Infectious Diseases and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Dimakatso A Senthebane
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Cape Town, South Africa.,Division of Medical Biochemistry and Institute of Infectious Disease and Molecular Medicine, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
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25
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Raslan AA, Yoon JK. R-spondins: Multi-mode WNT signaling regulators in adult stem cells. Int J Biochem Cell Biol 2019; 106:26-34. [DOI: 10.1016/j.biocel.2018.11.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 11/04/2018] [Accepted: 11/09/2018] [Indexed: 01/08/2023]
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26
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Spit M, Koo BK, Maurice MM. Tales from the crypt: intestinal niche signals in tissue renewal, plasticity and cancer. Open Biol 2018; 8:rsob.180120. [PMID: 30209039 PMCID: PMC6170508 DOI: 10.1098/rsob.180120] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 08/17/2018] [Indexed: 02/06/2023] Open
Abstract
Rapidly renewing tissues such as the intestinal epithelium critically depend on the activity of small-sized stem cell populations that continuously generate new progeny to replace lost and damaged cells. The complex and tightly regulated process of intestinal homeostasis is governed by a variety of signalling pathways that balance cell proliferation and differentiation. Accumulating evidence suggests that stem cell control and daughter cell fate determination is largely dictated by the microenvironment. Here, we review recent developments in the understanding of intestinal stem cell dynamics, focusing on the roles, mechanisms and interconnectivity of prime signalling pathways that regulate stem cell behaviour in intestinal homeostasis. Furthermore, we discuss how mutational activation of these signalling pathways endows colorectal cancer cells with niche-independent growth advantages during carcinogenesis.
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Affiliation(s)
- Maureen Spit
- Cell Biology, Center for Molecular Medicine, UMC Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Bon-Kyoung Koo
- IMBA - Institute of Molecular Biotechnology, Dr Bohr-Gasse 3, 1030 Vienna, Austria
| | - Madelon M Maurice
- Cell Biology, Center for Molecular Medicine, UMC Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands .,Oncode Institute, The Netherlands
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27
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Martin C, Cho YE, Kim H, Yun S, Kanefsky R, Lee H, Mysliwiec V, Cashion A, Gill J. Altered DNA Methylation Patterns Associated With Clinically Relevant Increases in PTSD Symptoms and PTSD Symptom Profiles in Military Personnel. Biol Res Nurs 2018; 20:352-358. [PMID: 29514460 PMCID: PMC5993080 DOI: 10.1177/1099800418758951] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Military personnel experience posttraumatic stress disorder (PTSD), which is associated with differential DNA methylation across the whole genome. However, the relationship between these DNA methylation patterns and clinically relevant increases in PTSD severity is not yet clearly understood. The purpose of this study was to identify differences in DNA methylation associated with PTSD symptoms and investigate DNA methylation changes related to increases in the severity of PTSD in military personnel. In this pilot study, a cross-sectional comparison was made between military personnel with PTSD (n = 8) and combat-matched controls without PTSD (n = 6). Symptom measures were obtained, and genome-wide DNA methylation was measured using methylated DNA immunoprecipitation (MeDIP-seq) from whole blood samples at baseline and 3 months later. A longitudinal comparison measured DNA methylation changes in military personnel with clinically relevant increases in PTSD symptoms between time points (PTSD onset) and compared methylation patterns to controls with no clinical changes in PTSD. In military personnel with elevated PTSD symptoms 3 months following baseline, 119 genes exhibited reduced methylation and 8 genes exhibited increased methylation. Genes with reduced methylation in the PTSD-onset group relate to the canonical pathways of netrin signaling, Wnt/Ca+ pathway, and axonal guidance signaling. These gene pathways relate to neurological disorders, and the current findings suggest that these epigenetic changes potentially relate to PTSD symptomology. This study provides some novel insights into the role of epigenetic changes in PTSD symptoms and the progression of PTSD symptoms in military personnel.
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Affiliation(s)
- Christiana Martin
- National Institute of Nursing Research (NINR),
National Institutes of Health, Bethesda, MD, USA
- Christiana Martin and Young-Eun Cho are
co-first authors
| | - Young-Eun Cho
- National Institute of Nursing Research (NINR),
National Institutes of Health, Bethesda, MD, USA
- Christiana Martin and Young-Eun Cho are
co-first authors
| | - Hyungsuk Kim
- National Institute of Nursing Research (NINR),
National Institutes of Health, Bethesda, MD, USA
| | | | - Rebekah Kanefsky
- National Institute of Nursing Research (NINR),
National Institutes of Health, Bethesda, MD, USA
| | - Hyunhwa Lee
- University of Nevada, School of Nursing, Las
Vegas, NV, USA
| | | | - Ann Cashion
- National Institute of Nursing Research (NINR),
National Institutes of Health, Bethesda, MD, USA
| | - Jessica Gill
- National Institute of Nursing Research (NINR),
National Institutes of Health, Bethesda, MD, USA
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28
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Abstract
Wnt/β-catenin signaling is crucial for adult homeostasis and stem cell maintenance, and its dysregulation is strongly associated to cancer. Upon Wnt binding, Wnt receptors assemble into large complexes called signalosomes that provide a platform for interactions with downstream effector proteins. The assembly and regulation of these signalosomes remains largely elusive. Here, we use internally tagged Wnt ligands as a tool to isolate and analyze the composition and regulation of endogenous Wnt receptor complexes. We identify a positive regulator of Wnt signaling that facilitates signalosome formation by promoting intramembrane receptor interactions. Our results reveal that the assembly of multiprotein Wnt signalosomes proceeds along well-ordered steps and involves regulated intramembrane interactions. Wnt/β-catenin signaling controls development and adult tissue homeostasis by regulating cell proliferation and cell fate decisions. Wnt binding to its receptors Frizzled (FZD) and low-density lipoprotein-related 6 (LRP6) at the cell surface initiates a signaling cascade that leads to the transcription of Wnt target genes. Upon Wnt binding, the receptors assemble into large complexes called signalosomes that provide a platform for interactions with downstream effector proteins. The molecular basis of signalosome formation and regulation remains elusive, largely due to the lack of tools to analyze its endogenous components. Here, we use internally tagged Wnt3a proteins to isolate and characterize activated, endogenous Wnt receptor complexes by mass spectrometry-based proteomics. We identify the single-span membrane protein TMEM59 as an interactor of FZD and LRP6 and a positive regulator of Wnt signaling. Mechanistically, TMEM59 promotes the formation of multimeric Wnt–FZD assemblies via intramembrane interactions. Subsequently, these Wnt–FZD–TMEM59 clusters merge with LRP6 to form mature Wnt signalosomes. We conclude that the assembly of multiprotein Wnt signalosomes proceeds along well-ordered steps that involve regulated intramembrane interactions.
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29
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Driehuis E, Clevers H. WNT signalling events near the cell membrane and their pharmacological targeting for the treatment of cancer. Br J Pharmacol 2017; 174:4547-4563. [PMID: 28244067 PMCID: PMC5727251 DOI: 10.1111/bph.13758] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 02/16/2017] [Accepted: 02/18/2017] [Indexed: 12/16/2022] Open
Abstract
WNT signalling is an essential signalling pathway for all multicellular animals. Although first described more than 30 years ago, new components and regulators of the pathway are still being discovered. Considering its importance in both embryonic development and adult homeostasis, it is not surprising that this pathway is often deregulated in human diseases such as cancer. Recently, it became clear that in addition to cytoplasmic components such as β-catenin, other, membrane-bound or extracellular, components of the WNT pathway are also altered in cancer. This review gives an overview of the recent discoveries on WNT signalling events near the cell membrane. Furthermore, membrane-associated components of the WNT pathway, which are more accessible for therapeutic intervention, as well therapeutic approaches that already target those components will be discussed. In this way, we hope to stimulate the development of effective anti-cancer therapies that target this fascinating pathway. LINKED ARTICLES This article is part of a themed section on WNT Signalling: Mechanisms and Therapeutic Opportunities. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.24/issuetoc.
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Affiliation(s)
- Else Driehuis
- Hubrecht InstituteRoyal Netherlands Academy of Arts and Sciences (KNAW)UtrechtThe Netherlands
- University medical center (UMC)UtrechtThe Netherlands
| | - Hans Clevers
- Hubrecht InstituteRoyal Netherlands Academy of Arts and Sciences (KNAW)UtrechtThe Netherlands
- University medical center (UMC)UtrechtThe Netherlands
- Princess Maxime Center (PMC)UtrechtThe Netherlands
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30
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Flanagan DJ, Vincan E, Phesse TJ. Winding back Wnt signalling: potential therapeutic targets for treating gastric cancers. Br J Pharmacol 2017; 174:4666-4683. [PMID: 28568899 DOI: 10.1111/bph.13890] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 05/17/2017] [Accepted: 05/22/2017] [Indexed: 12/21/2022] Open
Abstract
Gastric cancer persists as a frequent and deadly disease that claims over 700 000 lives annually. Gastric cancer is a multifactorial disease that is genetically, cytologically and architecturally more heterogeneous than other gastrointestinal cancers, making it therapeutically challenging. As such, and largely attributed to late-stage diagnosis, gastric cancer patients show only partial response to standard chemo and targeted molecular therapies, highlighting an urgent need to develop new targeted therapies for this disease. Wnt signalling has a well-documented history in the genesis of many cancers and is, therefore, an attractive therapeutic target. As such, drug discovery has focused on developing inhibitors that target multiple nodes of the Wnt signalling cascade, some of which have progressed to clinical trials. The collective efforts of patient genomic profiling has uncovered genetic lesions to multiple components of the Wnt pathway in gastric cancer patients, which strongly suggest that Wnt-targeted therapies could offer therapeutic benefits for gastric cancer patients. These data have been supported by studies in mouse models of gastric cancer, which identify Wnt signalling as a driver of gastric tumourigenesis. Here, we review the current literature regarding Wnt signalling in gastric cancer and highlight the suitability of each class of Wnt inhibitor as a potential treatment for gastric cancer patients, in relation to the type of Wnt deregulation observed. LINKED ARTICLES This article is part of a themed section on WNT Signalling: Mechanisms and Therapeutic Opportunities. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.24/issuetoc.
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Affiliation(s)
- Dustin J Flanagan
- Molecular Oncology Laboratory, University of Melbourne, Melbourne, VIC, Australia.,Victorian Infectious Diseases Reference Laboratory, Doherty Institute of Infection and Immunity, Melbourne, VIC, Australia
| | - Elizabeth Vincan
- Molecular Oncology Laboratory, University of Melbourne, Melbourne, VIC, Australia.,Victorian Infectious Diseases Reference Laboratory, Doherty Institute of Infection and Immunity, Melbourne, VIC, Australia.,School of Biomedical Sciences, Curtin University, Perth, WA, Australia
| | - Toby J Phesse
- Molecular Oncology Laboratory, University of Melbourne, Melbourne, VIC, Australia.,Victorian Infectious Diseases Reference Laboratory, Doherty Institute of Infection and Immunity, Melbourne, VIC, Australia.,Cell Signalling and Cancer Laboratory, European Cancer Stem Cell Research Institute, Cardiff University, Cardiff, UK
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31
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Qin H, Cai A, Xi H, Yuan J, Chen L. ZnRF3 Induces Apoptosis of Gastric Cancer Cells by Antagonizing Wnt and Hedgehog Signaling. Cell Biochem Biophys 2017; 73:361-367. [PMID: 27352324 DOI: 10.1007/s12013-015-0607-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A large proportion of malignant cancers of the stomach are gastric adenocarcinoma type. In spite of many studies, the molecular basis for this cancer is still unclear. Deregulated cell proliferative signaling via Wnt/β-catenin and Hedgehog pathways is considered important in the pathogenesis of many cancers including the gastric cancer. Recent studies identified ZnRF3 protein, which is a E3-ubiquitin ligase and which is either deleted or mutated in cancers, to inhibit Wnt signaling. However, the significance of ZnRF3 in the control of gastric cancer and whether it also regulates Hedgehog signaling pathway, is not known. In the present study, we assessed the expression of ZnRF3 in gastric tumors and paracancerous tissues from 58 patients (44 male and 14 female) of different ages and related this to patient survival. We observed a clear relationship between ZnRF3 expression in paracancerous tissue and tumor size. Also, ZnRF3 expression was much higher in tumors from aged patients. Male patients showed higher mortality than the females. Mechanistic studies using normal gastric cells (GES1) and gastric cancer cells (MGC-803) infected with either AdZnRF3 or AdGFP viral vectors, revealed that ZnRF3 overexpression causes significantly more apoptosis and lowered proliferation of cancer cells. ZnRF3 overexpression led to greatly reduced levels of Lgr5, a component of Wnt signaling and also Gli1, a component of Hedgehog signaling. Thus, ZnRF3 negatively influences both the Wnt and Hedgehog proliferative pathways, and probably this way it negatively regulates cancer progression. These results suggest the importance of normal ZnRF3 function in checking the progression of cancer cell growth and indicate that a lack of this protein can lead to poorer clinical outcomes for gastric cancer patients.
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Affiliation(s)
- Hongzhen Qin
- Department of General Surgery, Chinese PLA General Hospital, Beijing, China
| | - Aizhen Cai
- Department of General Surgery, Chinese PLA General Hospital, Beijing, China
| | - Hongqing Xi
- Department of General Surgery, Chinese PLA General Hospital, Beijing, China
| | - Jing Yuan
- Department of Pathology, Chinese PLA General Hospital, Beijing, China
| | - Lin Chen
- Department of General Surgery, Chinese PLA General Hospital, Beijing, China.
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32
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De Nardis C, Lössl P, van den Biggelaar M, Madoori PK, Leloup N, Mertens K, Heck AJR, Gros P. Recombinant Expression of the Full-length Ectodomain of LDL Receptor-related Protein 1 (LRP1) Unravels pH-dependent Conformational Changes and the Stoichiometry of Binding with Receptor-associated Protein (RAP). J Biol Chem 2016; 292:912-924. [PMID: 27956551 DOI: 10.1074/jbc.m116.758862] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 12/09/2016] [Indexed: 12/11/2022] Open
Abstract
LDL receptor-related protein 1 (LRP1) is a highly modular protein and the largest known mammalian endocytic receptor. LRP1 binds and internalizes many plasma components, playing multiple crucial roles as a scavenger and signaling molecule. One major challenge to studying LRP1 has been that it is difficult to express such a large, highly glycosylated, and cysteine-rich protein, limiting structural studies to LRP1 fragments. Here, we report the first recombinant expression of the complete 61 domains of the full-length LRP1 ectodomain. This advance was achieved with a multistep cloning approach and by using DNA dilutions to improve protein yields. We investigated the binding properties of LRP1 using receptor-associated protein (RAP) as a model ligand due to its tight binding interaction. The LRP1 conformation was studied in its bound and unbound state using mass spectrometry, small-angle X-ray scattering, and negative-stain electron microscopy at neutral and acidic pH. Our findings revealed a pH-dependent release of the ligand associated with a conformational change of the receptor. In summary, this investigation of the complete LRP1 ectodomain significantly advances our understanding of this important receptor and provides the basis for further elucidating the mechanism of action of LRP1 in a whole and integrated system.
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Affiliation(s)
- Camilla De Nardis
- From the Crystal & Structural Chemistry Group, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht
| | - Philip Lössl
- the Biomolecular Mass Spectrometry & Proteomics Group and Netherlands Proteomics Center, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CH Utrecht
| | | | - Pramod K Madoori
- From the Crystal & Structural Chemistry Group, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht
| | - Nadia Leloup
- From the Crystal & Structural Chemistry Group, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht
| | - Koen Mertens
- the Department of Plasma Proteins, Sanquin Research, 1006 AN Amsterdam, and.,the Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Albert J R Heck
- the Biomolecular Mass Spectrometry & Proteomics Group and Netherlands Proteomics Center, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CH Utrecht
| | - Piet Gros
- From the Crystal & Structural Chemistry Group, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht,
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33
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Abstract
Axon guidance relies on a combinatorial code of receptor and ligand interactions that direct adhesive/attractive and repulsive cellular responses. Recent structural data have revealed many of the molecular mechanisms that govern these interactions and enabled the design of sophisticated mutant tools to dissect their biological functions. Here, we discuss the structure/function relationships of four major classes of guidance cues (ephrins, semaphorins, slits, netrins) and examples of morphogens (Wnt, Shh) and of cell adhesion molecules (FLRT). These cell signaling systems rely on specific modes of receptor-ligand binding that are determined by selective binding sites; however, defined structure-encoded receptor promiscuity also enables cross talk between different receptor/ligand families and can also involve extracellular matrix components. A picture emerges in which a multitude of highly context-dependent structural assemblies determines the finely tuned cellular behavior required for nervous system development.
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Affiliation(s)
- Elena Seiradake
- Department of Biochemistry, Oxford University, Oxford OX1 3QU, United Kingdom;
| | - E Yvonne Jones
- Wellcome Trust Centre for Human Genetics, Oxford University, Oxford OX3 7BN, United Kingdom;
| | - Rüdiger Klein
- Max Planck Institute of Neurobiology, 82152 Munich-Martinsried, Germany;
- Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
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34
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ZNRF3 is downregulated in papillary thyroid carcinoma and suppresses the proliferation and invasion of papillary thyroid cancer cells. Tumour Biol 2016; 37:12665-12672. [PMID: 27448298 DOI: 10.1007/s13277-016-5250-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 07/15/2016] [Indexed: 12/22/2022] Open
Abstract
Zinc and ring finger 3 (ZNRF3) is a transmembrane E3 ubiquitin ligase that has emerged as an important regulator of cancer development; however, its cancer-related function remains controversial. Here, we investigated the possible role of ZNRF3 in thyroid carcinoma (TC). We found that ZNRF3 is downregulated in papillary thyroid carcinoma (PTC) compared to normal thyroid tissues and inversely correlated with the degree of cell differentiation. Overexpression of ZNRF3 significantly suppressed cell malignant behaviors, including cell proliferation, migration, and invasion in vitro, as well as tumor growth in vivo. Consistent with recent studies showing that ZNRF3 is involved in the Wnt/β-catenin pathway, ZNRF3 overexpression negatively regulated β-catenin activation, modulating PTC cell behaviors. Clinical specimens revealed a significant inverse correlation between ZNRF3 and β-catenin mRNA levels. Taken together, these results provide insight into a potential tumor suppressor role of ZNRF3 in PTC progression, and may have potential clinical relevance for the prognosis and treatment of PTC.
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35
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Jiang X, Cong F. Novel Regulation of Wnt Signaling at the Proximal Membrane Level. Trends Biochem Sci 2016; 41:773-783. [PMID: 27377711 DOI: 10.1016/j.tibs.2016.06.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 06/03/2016] [Accepted: 06/07/2016] [Indexed: 02/06/2023]
Abstract
Wnt pathways are crucial for embryonic development and adult tissue homeostasis in all multicellular animals. Our understanding of Wnt signaling networks has grown increasingly complex. Recent studies have revealed many regulatory proteins that function at the proximal membrane level to fine-tune signaling output and enhance signaling specificity. These proteins regulate crucial points in Wnt signaling, including post-translational modification of Wnt proteins, regulation of Wnt receptor degradation, internalization of Wnt receptor complex, and specific ligand-receptor complex formation. Such regulators not only provide us with molecular details of Wnt regulation but also serve as potential targets for therapeutic intervention. In this review we highlight new insights into Wnt regulation at the plasma membrane, especially newly identified feedback regulators.
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Affiliation(s)
- Xiaomo Jiang
- Novartis Institutes for Biomedical Research, 181 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Feng Cong
- Novartis Institutes for Biomedical Research, 181 Massachusetts Avenue, Cambridge, MA 02139, USA.
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36
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Chang CF, Hsu LS, Weng CY, Chen CK, Wang SY, Chou YH, Liu YY, Yuan ZX, Huang WY, Lin H, Chen YH, Tsai JN. N-Glycosylation of Human R-Spondin 1 Is Required for Efficient Secretion and Stability but Not for Its Heparin Binding Ability. Int J Mol Sci 2016; 17:ijms17060937. [PMID: 27314333 PMCID: PMC4926470 DOI: 10.3390/ijms17060937] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Revised: 05/31/2016] [Accepted: 06/07/2016] [Indexed: 01/01/2023] Open
Abstract
R-spondin 1 (Rspo1) plays an essential role in stem cell biology by potentiating Wnt signaling activity. Despite the fact that Rspo1 holds therapeutic potential for a number of diseases, its biogenesis is not fully elucidated. All Rspo proteins feature two amino-terminal furin-like repeats, which are responsible for Wnt signal potentiation, and a thrombospondin type 1 (TSR1) domain that can provide affinity towards heparan sulfate proteoglycans. Using chemical inhibitors, deglycosylase and site-directed mutagenesis, we found that human Rspo1 and Rspo3 are both N-glycosylated at N137, a site near the C-terminus of the furin repeat 2 domain, and Rspo2 is N-glycosylated at N160, a position near the N-terminus of TSR1 domain. Elimination of N-glycosylation at these sites affects their accumulation in media but have no effect on the ability towards heparin. Introduction of the N-glycosylation site to Rspo2 mutant at the position homologous to N137 in Rspo1 restored full glycosylation and rescued the accumulation defect of nonglycosylated Rspo2 mutant in media. Similar effect can be observed in the N137 Rspo1 or Rspo3 mutant engineered with Rspo2 N-glycosylation site. The results highlight the importance of N-glycosylation at these two positions in efficient folding and secretion of Rspo family. Finally, we further showed that human Rspo1 is subjected to endoplasmic reticulum (ER) quality control in N-glycan-dependent manner. While N-glycan of Rspo1 plays a role in its intracellular stability, it had little effect on secreted Rspo1. Our findings provide evidence for the critical role of N-glycosylation in the biogenesis of Rspo1.
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Affiliation(s)
- Chiung-Fang Chang
- Department of Life Sciences, National Chung Hsing University, Taichung 40227, Taiwan.
| | - Li-Sung Hsu
- Institute of Biochemistry and Biotechnology, Chung Shan Medical University, Taichung 40201, Taiwan.
- Clinical Laboratory, Chung Shan Medical University Hospital, Taichung 40201, Taiwan.
| | - Chieh-Yu Weng
- Department of Medical Laboratory and Biotechnology, Chung Shan Medical University, Taichung 40201, Taiwan.
| | - Chih-Kai Chen
- Department of Medical Laboratory and Biotechnology, Chung Shan Medical University, Taichung 40201, Taiwan.
| | - Shu-Ying Wang
- Department of Medical Laboratory and Biotechnology, Chung Shan Medical University, Taichung 40201, Taiwan.
| | - Yi-Hwa Chou
- Department of Medical Laboratory and Biotechnology, Chung Shan Medical University, Taichung 40201, Taiwan.
| | - Yan-Yu Liu
- Department of Medical Laboratory and Biotechnology, Chung Shan Medical University, Taichung 40201, Taiwan.
| | - Zi-Xiu Yuan
- Department of Medical Laboratory and Biotechnology, Chung Shan Medical University, Taichung 40201, Taiwan.
| | - Wen-Ying Huang
- Department of Medical Laboratory and Biotechnology, Chung Shan Medical University, Taichung 40201, Taiwan.
| | - Ho Lin
- Department of Life Sciences, National Chung Hsing University, Taichung 40227, Taiwan.
| | - Yau-Hung Chen
- Department of Chemistry, Tamkang University, Tamsui, New Taipei City 25137, Taiwan.
| | - Jen-Ning Tsai
- Clinical Laboratory, Chung Shan Medical University Hospital, Taichung 40201, Taiwan.
- Department of Medical Laboratory and Biotechnology, Chung Shan Medical University, Taichung 40201, Taiwan.
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Control of Wnt Receptor Turnover by R-spondin-ZNRF3/RNF43 Signaling Module and Its Dysregulation in Cancer. Cancers (Basel) 2016; 8:cancers8060054. [PMID: 27338477 PMCID: PMC4931619 DOI: 10.3390/cancers8060054] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 05/23/2016] [Accepted: 06/02/2016] [Indexed: 12/25/2022] Open
Abstract
Aberrant activation of the Wnt/β-catenin pathway is frequently found in various cancers, often through mutations of downstream components. Inhibiting β-catenin signaling in tumors with downstream pathway mutations remains challenging, due to a lack of favorable targets. On the other hand, targeting upstream components of the Wnt pathway is rather straightforward. However, it is difficult to identify tumors addicted to autocrine or paracrine Wnt signaling. Discovery of the R-spondin-ZNRF3/RNF43 signaling module and its genetic alterations in cancers represents a breakthrough in this area. Membrane E3 ligase ZNRF3 and RNF43 are critical negative feedback regulators of the Wnt pathway, which function through promoting ubiquitination and degradation of Wnt receptors. R-spondin proteins (RSPO1-4) serve as natural antagonists of ZNRF3/RNF43. To maintain strong and sustained Wnt/β-catenin signaling, cancers need to overcome ZNRF3/RNF43-mediated feedback inhibition. Indeed, mutations of RNF43/ZNRF3 and recurrent translocations of RSPO2/RSPO3 have recently been identified in various cancers. Significantly, genetic alterations in RNF43/ZNRF3/RSPO2/RSPO3 have shown promise as predictive biomarkers in pre-clinical models for the efficacy of upstream Wnt inhibitors. In this review, we will discuss the biology of the R-spondin-ZNRF3/RNF43 signaling module, cancer-associated alterations of this signaling module, and their value as biomarkers to identify Wnt-addicted tumors.
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Frizzled7: A Promising Achilles' Heel for Targeting the Wnt Receptor Complex to Treat Cancer. Cancers (Basel) 2016; 8:cancers8050050. [PMID: 27196929 PMCID: PMC4880867 DOI: 10.3390/cancers8050050] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 05/03/2016] [Accepted: 05/09/2016] [Indexed: 02/07/2023] Open
Abstract
Frizzled7 is arguably the most studied member of the Frizzled family, which are the cognate Wnt receptors. Frizzled7 is highly conserved through evolution, from Hydra through to humans, and is expressed in diverse organisms, tissues and human disease contexts. Frizzled receptors can homo- or hetero-polymerise and associate with several co-receptors to transmit Wnt signalling. Notably, Frizzled7 can transmit signalling via multiple Wnt transduction pathways and bind to several different Wnt ligands, Frizzled receptors and co-receptors. These promiscuous binding and functional properties are thought to underlie the pivotal role Frizzled7 plays in embryonic developmental and stem cell function. Recent studies have identified that Frizzled7 is upregulated in diverse human cancers, and promotes proliferation, progression and invasion, and orchestrates cellular transitions that underscore cancer metastasis. Importantly, Frizzled7 is able to regulate Wnt signalling activity even in cancer cells which have mutations to down-stream signal transducers. In this review we discuss the various aspects of Frizzled7 signalling and function, and the implications these have for therapeutic targeting of Frizzled7 in cancer.
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Kang E, Yousefi M, Gruenheid S. R-Spondins Are Expressed by the Intestinal Stroma and are Differentially Regulated during Citrobacter rodentium- and DSS-Induced Colitis in Mice. PLoS One 2016; 11:e0152859. [PMID: 27046199 PMCID: PMC4821485 DOI: 10.1371/journal.pone.0152859] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 03/21/2016] [Indexed: 11/18/2022] Open
Abstract
The R-spondin family of proteins has recently been described as secreted enhancers of β-catenin activation through the canonical Wnt signaling pathway. We previously reported that Rspo2 is a major determinant of susceptibility to Citrobacter rodentium-mediated colitis in mice and recent genome-wide association studies have revealed RSPO3 as a candidate Crohn's disease-specific inflammatory bowel disease susceptibility gene in humans. However, there is little information on the endogenous expression and cellular source of R-spondins in the colon at steady state and during intestinal inflammation. RNA sequencing and qRT-PCR were used to assess the expression of R-spondins at steady state and in two mouse models of colonic inflammation. The cellular source of R-spondins was assessed in specific colonic cell populations isolated by cell sorting. Data mining from publicly available datasets was used to assess the expression of R-spondins in the human colon. At steady state, colonic expression of R-spondins was found to be exclusive to non-epithelial CD45- lamina propria cells, and Rspo3/RSPO3 was the most highly expressed R-spondin in both mouse and human colon. R-spondin expression was found to be highly dynamic and differentially regulated during C. rodentium infection and dextran sodium sulfate (DSS) colitis, with notably high levels of Rspo3 expression during DSS colitis, and high levels of Rspo2 expression during C. rodentium infection, specifically in susceptible mice. Our data are consistent with the hypothesis that in the colon, R-spondins are expressed by subepithelial stromal cells, and that Rspo3/RSPO3 is the family member most implicated in colonic homeostasis. The differential regulation of the R-spondins in different models of intestinal inflammation indicate they respond to specific pathogenic and inflammatory signals that differ in the two models and provides further evidence that this family of proteins plays a key role in linking intestinal inflammation and homeostasis.
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Affiliation(s)
- Eugene Kang
- Department of Microbiology and Immunology and Complex Traits Group, McGill University, Montreal, Quebec, Canada
| | - Mitra Yousefi
- Department of Microbiology and Immunology and Complex Traits Group, McGill University, Montreal, Quebec, Canada
| | - Samantha Gruenheid
- Department of Microbiology and Immunology and Complex Traits Group, McGill University, Montreal, Quebec, Canada
- * E-mail:
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Abstract
Wnt pathways are critical for embryonic development and adult tissue homeostasis in all multicellular animals. Many regulatory mechanisms exist to control proper signaling output. Recent studies suggest that cell surface Wnt receptor level is controlled by ubiquitination, and serve as a critical regulatory point of Wnt pathway activity as it determines the responsiveness of cells to Wnt signal. Here, we describe flow cytometry, cell surface protein biotinylation, and immunofluorescence pulse-chase methods to probe the surface expression, ubiquitination, and internalization of the Wnt receptors FZD and LRP6.
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Affiliation(s)
- Xiaomo Jiang
- Immuno-oncology, Novartis Institutes for Biomedical Research, Cambridge, MA, USA
| | - Feng Cong
- Developmental and Molecular Pathways, Novartis Institutes for Biomedical Research, 250 Massachusetts Avenue, Cambridge, MA, 02139, USA.
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Zebisch M, Jones EY. ZNRF3/RNF43--A direct linkage of extracellular recognition and E3 ligase activity to modulate cell surface signalling. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 118:112-8. [PMID: 25937466 DOI: 10.1016/j.pbiomolbio.2015.04.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2015] [Revised: 04/20/2015] [Accepted: 04/22/2015] [Indexed: 01/16/2023]
Abstract
The interactions of extracellular ligands with single membrane spanning receptors, such as kinases, typically serve to agonise or antagonise the intracellular activation of signalling pathways. Within the cell, E3 ligases can act to alter the localisation and activity of proteins involved in signalling systems. Structural and functional characterisation of two closely related single membrane spanning molecules, RNF43 and ZNRF3, has recently revealed the receptor-like functionalities of a ligand-binding ectodomain combined with the intracellular architecture and activity of an E3 ligase. This direct link provides a hereto novel mechanism for extracellular control of ubiquitin ligase activity that is used for the modulation of Wnt signalling, a pathway of major importance in embryogenesis, stem cell biology and cancer. In this review we discuss recent findings for the structure and interactions of the extracellular region of RNF43/ZNRF3 and draw parallels with the properties and function of signalling receptor ectodomains.
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Affiliation(s)
- Matthias Zebisch
- Evotec (UK) Ltd, 114 Innovation Drive, Milton Park, Abingdon, Oxfordshire OX14 4RZ, United Kingdom
| | - E Yvonne Jones
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, United Kingdom.
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Zebisch M, Jones EY. Crystal structure of R-spondin 2 in complex with the ectodomains of its receptors LGR5 and ZNRF3. J Struct Biol 2015; 191:149-55. [PMID: 26123262 PMCID: PMC4533229 DOI: 10.1016/j.jsb.2015.05.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 04/30/2015] [Accepted: 05/18/2015] [Indexed: 12/27/2022]
Abstract
The four secreted R-spondin (Rspo1-4) proteins of vertebrates function as stem cell growth factors and potentiate canonical Wnt signalling. Rspo proteins act by cross-linking members of two cell surface receptor families, complexing the stem cell markers LGR4-6 with the Frizzled-specific E3 ubiquitin ligases ZNRF3/RNF43. The consequent internalisation of the ternary LGR-Rspo-E3 complex removes the E3 ligase activity, which otherwise targets the Wnt receptor Frizzled for degradation, and thus enhances Wnt signalling. Multiple combinations of LGR4-6, Rspo1-4 and ZNRF3/RNF43 are possible, implying the existence of generic interaction determinants, but also of specific differences in complex architecture and activity. We present here a high resolution crystal structure of an ectodomain variant of human LGR5 (hLGR5ecto) complexed with a signalling competent fragment of mouse Rspo2 (mRspo2Fu1-Fu2). The structure shows that the particularly potent Rspo2 ligand engages LGR5 in a fashion almost identical to that reported for hRSPO1. Comparison of our hLGR5ecto structure with previously published structures highlights a surprising plasticity of the LGR ectodomains, characterised by a nearly 9° or larger rotation of the N-terminal half of the horseshoe-like fold relative to the C-terminal half. We also report a low resolution hLGR5-mRspo2Fu1-Fu2-mZNRF3ecto ternary complex structure. This crystal structure confirms our previously suggested hypothesis, showing that Rspo proteins cross-link LGRs and ZNRF3 into a 2:2:2 complex, whereas a 1:1:1 complex is formed with RNF43.
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Affiliation(s)
- Matthias Zebisch
- Division of Structural Biology, Henry Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - E Yvonne Jones
- Division of Structural Biology, Henry Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, United Kingdom.
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43
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Koo BK, van Es JH, van den Born M, Clevers H. Porcupine inhibitor suppresses paracrine Wnt-driven growth of Rnf43;Znrf3-mutant neoplasia. Proc Natl Acad Sci U S A 2015; 112:7548-50. [PMID: 26023187 PMCID: PMC4475934 DOI: 10.1073/pnas.1508113112] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Rnf43 (RING finger protein 43) and Znrf3 (zinc/RING finger protein 3) (RZ) are two closely related transmembrane E3 ligases, encoded by Wnt target genes, that remove surface Wnt (wingless-int) receptors. The two genes are mutated in various human cancers. Such tumors are predicted to be hypersensitive to, yet still depend on, secreted Wnts. We previously showed that mutation of RZ in the intestine yields rapidly growing adenomas containing LGR5(+) (leucine-rich repeat-containing G-protein coupled receptor 5) stem cells and Wnt3-producing Paneth cells. We now show that removal of Paneth cells by Math1 mutation inhibits RZ(-/-) tumor formation. Similarly, deletion of Wnt3 inhibits tumorigenesis. Treatment of mice carrying RZ(-/-) intestinal neoplasia with a small molecule Wnt secretion inhibitor (porcupine inhibitor C59) strongly inhibited growth, whereas adjacent normal crypts remained intact. These results establish that paracrine Wnt secretion is an essential driver of RZ(-/-) tumor growth and imply that a therapeutic window exists for the use of porcupine inhibitors for RZ-mutant cancers.
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Affiliation(s)
- Bon-Kyoung Koo
- Hubrecht Institute for Developmental Biology and Stem Cell Research, University Medical Centre Utrecht, Uppsalalaan 8, 3584CT Utrecht, The Netherlands
| | - Johan H van Es
- Hubrecht Institute for Developmental Biology and Stem Cell Research, University Medical Centre Utrecht, Uppsalalaan 8, 3584CT Utrecht, The Netherlands
| | - Maaike van den Born
- Hubrecht Institute for Developmental Biology and Stem Cell Research, University Medical Centre Utrecht, Uppsalalaan 8, 3584CT Utrecht, The Netherlands
| | - Hans Clevers
- Hubrecht Institute for Developmental Biology and Stem Cell Research, University Medical Centre Utrecht, Uppsalalaan 8, 3584CT Utrecht, The Netherlands
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44
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Feng Q, Gao N. Keeping Wnt signalosome in check by vesicular traffic. J Cell Physiol 2015; 230:1170-80. [PMID: 25336320 DOI: 10.1002/jcp.24853] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 10/17/2014] [Indexed: 01/01/2023]
Abstract
Wg/Wnts are paracrine and autocrine ligands that activate distinct signaling pathways while being internalized through surface receptors. Converging and contrasting views are shaping our understanding of whether, where, and how endocytosis may modulate Wnt signaling. We gather considerable amount of evidences to elaborate the point that signal-receiving cells utilize distinct, flexible, and sophisticated vesicular trafficking mechanisms to keep Wnt signaling activity in check. Same molecules in a highly context-dependent fashion serve as regulatory hub for various signaling purposes: amplification, maintenance, inhibition, and termination. Updates are provided for the regulatory mechanisms related to the three critical cell surface complexes, Wnt-Fzd-LRP6, Dkk1-Kremen-LRP6, and R-spondin-LGR5-RNF43, which potently influence Wnt signaling. We pay particular attentions to how cells achieve sustained and delicate control of Wnt signaling strength by employing comprehensive aspects of vesicular trafficking.
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Affiliation(s)
- Qiang Feng
- Department of Biological Sciences, Rutgers University, Newark, New Jersey
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45
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Dishevelled promotes Wnt receptor degradation through recruitment of ZNRF3/RNF43 E3 ubiquitin ligases. Mol Cell 2015; 58:522-33. [PMID: 25891077 DOI: 10.1016/j.molcel.2015.03.015] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 01/26/2015] [Accepted: 03/11/2015] [Indexed: 12/31/2022]
Abstract
Tumor suppressors ZNRF3 and RNF43 inhibit Wnt signaling through promoting degradation of Wnt coreceptors Frizzled (FZD) and LRP6, and this activity is counteracted by stem cell growth factor R-spondin. The mechanism by which ZNRF3 and RNF43 recognize Wnt receptors remains unclear. Here we uncover an unexpected role of Dishevelled (DVL), a positive Wnt regulator, in promoting Wnt receptor degradation. DVL knockout cells have significantly increased cell surface levels of FZD and LRP6. DVL is required for ZNRF3/RNF43-mediated ubiquitination and degradation of FZD. Physical interaction with DVL is essential for the Wnt inhibitory activity of ZNRF3/RNF43. Binding of FZD through the DEP domain of DVL is required for DVL-mediated downregulation of FZD. Fusion of the DEP domain to ZNRF3/RNF43 overcomes their DVL dependency to downregulate FZD. Our study reveals DVL as a dual function adaptor to recruit negative regulators ZNRF3/RNF43 to Wnt receptors to ensure proper control of pathway activity.
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46
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Warner ML, Bell T, Pioszak AA. Engineering high-potency R-spondin adult stem cell growth factors. Mol Pharmacol 2014; 87:410-20. [PMID: 25504990 DOI: 10.1124/mol.114.095133] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Secreted R-spondin proteins (RSPOs1-4) function as adult stem cell growth factors by potentiating Wnt signaling. Simultaneous binding of distinct regions of the RSPO Fu1-Fu2 domain module to the extracellular domains (ECDs) of the LGR4 G protein-coupled receptor and the ZNRF3 transmembrane E3 ubiquitin ligase regulates Wnt receptor availability. Here, we examine the molecular basis for the differing signaling strengths of RSPOs1-4 using purified RSPO Fu1-Fu2, LGR4 ECD, and ZNRF3 ECD proteins in Wnt signaling and receptor binding assays, and we engineer novel high-potency RSPOs. RSPO2/3/4 had similar signaling potencies that were stronger than that of RSPO1, whereas RSPO1/2/3 had similar efficacies that were greater than that of RSPO4. The RSPOs bound LGR4 with affinity rank order RSPO4 > RSPO2/3 > RSPO1 and ZNRF3 with affinity rank order RSPO2/3 > > RSPO1 > RSPO4. An RSPO2-4 chimera combining RSPO2 ZNRF3 binding with RSPO4 LGR4 binding was a "Superspondin" that exhibited enhanced ternary complex formation and 10-fold stronger signaling potency than RSPO2 and efficacy equivalent to RSPO2. An RSPO4-1 chimera combining RSPO4 ZNRF3 binding with RSPO1 LGR4 binding was a "Poorspondin" that exhibited signaling potency similar to RSPO1 and efficacy equivalent to RSPO4. Conferring increased ZNRF3 binding upon RSPO4 with amino acid substitutions L56F, I58L, and I63M enhanced its signaling potency and efficacy. Our results reveal the molecular basis for RSPOs1-4 activity differences and suggest that signaling potency is determined by ternary complex formation ability, whereas efficacy depends on ZNRF3 recruitment. High-potency RSPOs may be of value for regenerative medicine and/or therapeutic applications.
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Affiliation(s)
- Margaret L Warner
- Department of Biochemistry and Molecular Biology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Tufica Bell
- Department of Biochemistry and Molecular Biology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Augen A Pioszak
- Department of Biochemistry and Molecular Biology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
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47
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Malinauskas T, Jones EY. Extracellular modulators of Wnt signalling. Curr Opin Struct Biol 2014; 29:77-84. [PMID: 25460271 DOI: 10.1016/j.sbi.2014.10.003] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 09/26/2014] [Accepted: 10/02/2014] [Indexed: 10/24/2022]
Abstract
Wnt morphogens are secreted signalling proteins that play leading roles in embryogenesis and tissue homeostasis throughout life. Wnt signalling is controlled by multiple mechanisms, including posttranslational modification of Wnts, antagonist binding (to Wnts or their receptors), and regulation of the availability of Wnt receptors. Recent crystallographic, structure-guided biophysical and cell-based studies have advanced our understanding of how Wnt signalling is regulated at the cell surface. Structures include Wnt in complex with the cysteine-rich domain (CRD) of Frizzled, extracellular fragments of Wnt co-receptor LRP6, LRP6-binding antagonists Dickkopf and Sclerostin, antagonists 5T4/WAIF1 and Wnt inhibitory factor 1 (WIF-1), as well as Frizzled-ubiquitin ligases ZNRF3/RNF43 (in isolation and in complexes with Wnt signalling promoters R-spondins and LGR5). We review recent discoveries and remaining questions.
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Affiliation(s)
- Tomas Malinauskas
- Cold Spring Harbor Laboratory, W. M. Keck Structural Biology Laboratory, Cold Spring Harbor, NY 11724, USA
| | - E Yvonne Jones
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, United Kingdom.
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48
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Koo BK, Clevers H. Stem cells marked by the R-spondin receptor LGR5. Gastroenterology 2014; 147:289-302. [PMID: 24859206 DOI: 10.1053/j.gastro.2014.05.007] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2014] [Revised: 05/12/2014] [Accepted: 05/16/2014] [Indexed: 12/14/2022]
Abstract
Since the discovery of LGR5 as a marker of intestinal stem cells, the field has developed explosively and led to many new avenues of research. The inner workings of the intestinal crypt stem cell niche are now well understood. The study of stem cell-enriched genes has uncovered some previously unknown aspects of the Wnt signaling pathway, the major driver of crypt dynamics. LGR5(+) stem cells can now be cultured over long periods in vitro as epithelial organoids or "mini-guts." This technology opens new possibilities of using cultured adult stem cells for drug development, disease modeling, gene therapy, and regenerative medicine. This review describes the rediscovery of crypt base columnar cells as LGR5(+) adult stem cells and summarizes subsequent progress, promises, unresolved issues, and challenges of the field.
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Affiliation(s)
- Bon-Kyoung Koo
- Wellcome Trust - Medical Research Council Stem Cell Institute, University of Cambridge, Cambridge, England; Department of Genetics, University of Cambridge, Cambridge, England
| | - Hans Clevers
- Hubrecht Institute/KNAW, Utrecht, The Netherlands; University Medical Center Utrecht, Utrecht, The Netherlands.
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49
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Abstract
Adult stem cells are controlled by an intricate interplay of potent Wnt agonists, antagonists, and anti-antagonists. This review by de Lau et al. focuses on the complex physical and functional interactions of three recently discovered protein families that control stem cell activity by regulating surface expression of Wnt receptors: Lgr5 and its homologs, the E3 ligases Rnf43 and Znrf3, and the secreted R-spondin ligands. Lgr5 was originally discovered as a common Wnt target gene in adult intestinal crypts and colon cancer. It was subsequently identified as an exquisite marker of multiple Wnt-driven adult stem cell types. Lgr5 and its homologs, Lgr4 and Lgr6, constitute the receptors for R-spondins, potent Wnt signal enhancers and stem cell growth factors. The Lgr5/R-spondin complex acts by neutralizing Rnf43 and Znrf3, two transmembrane E3 ligases that remove Wnt receptors from the stem cell surface. Rnf43/Znrf3 are themselves encoded by Wnt target genes and constitute a negative Wnt feedback loop. Thus, adult stem cells are controlled by an intricate interplay of potent Wnt agonists, antagonists, and anti-antagonists.
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Affiliation(s)
- Wim de Lau
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW), University Medical Centre Utrecht, 3584 CT Utrecht, The Netherlands
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50
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Abstract
R-spondins (RSPOs) and their receptor leucine-rich repeat-containing G-protein coupled receptor 4 (LGR4) play pleiotropic roles in normal and cancer development as well as the survival of adult stem cells through potentiation of Wnt signaling. Current evidence indicates that RSPO-LGR4 functions to elevate levels of Wnt receptors through direct inhibition of two membrane-bound E3 ligases (RNF43 and ZNRF3), which otherwise ubiquitinate Wnt receptors for degradation. Whether RSPO-LGR4 is coupled to intracellular signaling proteins to regulate Wnt pathways remains unknown. We identified the intracellular scaffold protein IQ motif containing GTPase-activating protein 1 (IQGAP1) as an LGR4-interacting protein that mediates RSPO-LGR4's interaction with the Wnt signalosome. IQGAP1 binds to and modulates the activities of a plethora of signaling molecules, including MAP kinases, Rho GTPases, and components of the Wnt signaling pathways. Interaction of LGR4 with IQGAP1 brings RSPO-LGR4 to the Wnt signaling complex through enhanced IQGAP1-DVL interaction following RSPO stimulation. In this configuration, RSPO-LGR4-IQGAP1 potentiates β-catenin-dependent signaling by promoting MEK1/2-medidated phosphorylation of LRP5/6 as well as β-catenin-independent signaling through regulation of actin dynamics. Overall, these findings reveal that RSPO-LGR4 not only induces the clearance of RNF43/ZNRF3 to increase Wnt receptor levels but also recruits IQGAP1 into the Wnt signaling complex, leading to potent and robust potentiation of both the canonical and noncanonical pathways of Wnt signaling.
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