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Abstract
Colorectal cancer (CRC) is a substantial source of global morbidity and mortality in dire need of improved prevention and treatment strategies. As our understanding of CRC grows, it is becoming increasingly evident that the gut microbiota, consisting of trillions of microorganisms in direct interface with the colon, plays a substantial role in CRC development and progression. Understanding the roles that individual microorganisms and complex microbial communities play in CRC pathogenesis, along with their attendant mechanisms, will help yield novel preventive and therapeutic interventions for CRC. In this Review, we discuss recent evidence concerning global perturbations of the gut microbiota in CRC, associations of specific microorganisms with CRC, the underlying mechanisms by which microorganisms potentially drive CRC development and the roles of complex microbial communities in CRC pathogenesis. While our understanding of the relationship between the microbiota and CRC has improved in recent years, our findings highlight substantial gaps in current research that need to be filled before this knowledge can be used to the benefit of patients.
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Affiliation(s)
- Maxwell T White
- Division of Infectious Diseases, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Cynthia L Sears
- Division of Infectious Diseases, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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2
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Sogari A, Rovera E, Grasso G, Mariella E, Reilly NM, Lamba S, Mauri G, Durinikova E, Vitiello PP, Lorenzato A, Avolio M, Piumatti E, Bonoldi E, Aquilano MC, Arena S, Sartore-Bianchi A, Siena S, Trusolino L, Donalisio M, Russo M, Di Nicolantonio F, Lembo D, Bardelli A. Tolerance to colibactin correlates with homologous recombination proficiency and resistance to irinotecan in colorectal cancer cells. Cell Rep Med 2024; 5:101376. [PMID: 38228147 PMCID: PMC10897517 DOI: 10.1016/j.xcrm.2023.101376] [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: 04/16/2023] [Revised: 11/08/2023] [Accepted: 12/15/2023] [Indexed: 01/18/2024]
Abstract
The bacterial genotoxin colibactin promotes colorectal cancer (CRC) tumorigenesis, but systematic assessment of its impact on DNA repair is lacking, and its effect on response to DNA-damaging chemotherapeutics is unknown. We find that CRC cell lines display differential response to colibactin on the basis of homologous recombination (HR) proficiency. Sensitivity to colibactin is induced by inhibition of ATM, which regulates DNA double-strand break repair, and blunted by HR reconstitution. Conversely, CRC cells chronically infected with colibactin develop a tolerant phenotype characterized by restored HR activity. Notably, sensitivity to colibactin correlates with response to irinotecan active metabolite SN38, in both cell lines and patient-derived organoids. Moreover, CRC cells that acquire colibactin tolerance develop cross-resistance to SN38, and a trend toward poorer response to irinotecan is observed in a retrospective cohort of CRCs harboring colibactin genomic island. Our results shed insight into colibactin activity and provide translational evidence on its chemoresistance-promoting role in CRC.
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Affiliation(s)
- Alberto Sogari
- Department of Oncology, Molecular Biotechnology Center, University of Torino, Torino, Italy; IFOM ETS - The AIRC Institute of Molecular Oncology, 20139 Milan, Italy
| | - Emanuele Rovera
- Department of Oncology, Molecular Biotechnology Center, University of Torino, Torino, Italy
| | - Gaia Grasso
- Department of Oncology, Molecular Biotechnology Center, University of Torino, Torino, Italy; IFOM ETS - The AIRC Institute of Molecular Oncology, 20139 Milan, Italy
| | - Elisa Mariella
- Department of Oncology, Molecular Biotechnology Center, University of Torino, Torino, Italy; IFOM ETS - The AIRC Institute of Molecular Oncology, 20139 Milan, Italy
| | | | - Simona Lamba
- Department of Oncology, Molecular Biotechnology Center, University of Torino, Torino, Italy
| | - Gianluca Mauri
- IFOM ETS - The AIRC Institute of Molecular Oncology, 20139 Milan, Italy; Department of Oncology and Hemato-Oncology, Università degli Studi di Milano, Milan, Italy; Department of Hematology, Oncology, and Molecular Medicine, Grande Ospedale Metropolitano Niguarda, Milan, Italy
| | | | - Pietro Paolo Vitiello
- Department of Oncology, Molecular Biotechnology Center, University of Torino, Torino, Italy; IFOM ETS - The AIRC Institute of Molecular Oncology, 20139 Milan, Italy
| | - Annalisa Lorenzato
- Department of Oncology, Molecular Biotechnology Center, University of Torino, Torino, Italy
| | - Marco Avolio
- Candiolo Cancer Institute, FPO-IRCCS, 10060 Candiolo, Italy
| | - Eleonora Piumatti
- Department of Oncology, Molecular Biotechnology Center, University of Torino, Torino, Italy; IFOM ETS - The AIRC Institute of Molecular Oncology, 20139 Milan, Italy
| | - Emanuela Bonoldi
- Department of Pathology, Grande Ospedale Metropolitano Niguarda, Milan, Italy
| | | | - Sabrina Arena
- Candiolo Cancer Institute, FPO-IRCCS, 10060 Candiolo, Italy; Department of Oncology, University of Torino, 10060 Candiolo, Italy
| | - Andrea Sartore-Bianchi
- Department of Oncology and Hemato-Oncology, Università degli Studi di Milano, Milan, Italy; Department of Hematology, Oncology, and Molecular Medicine, Grande Ospedale Metropolitano Niguarda, Milan, Italy; Division of Clinical Research and Innovation, Grande Ospedale Metropolitano Niguarda, Milan, Italy
| | - Salvatore Siena
- Department of Oncology and Hemato-Oncology, Università degli Studi di Milano, Milan, Italy; Department of Hematology, Oncology, and Molecular Medicine, Grande Ospedale Metropolitano Niguarda, Milan, Italy
| | - Livio Trusolino
- Candiolo Cancer Institute, FPO-IRCCS, 10060 Candiolo, Italy; Department of Oncology, University of Torino, 10060 Candiolo, Italy
| | - Manuela Donalisio
- Department of Clinical and Biological Sciences, University of Torino, 10043 Orbassano, Italy
| | - Mariangela Russo
- Department of Oncology, Molecular Biotechnology Center, University of Torino, Torino, Italy; IFOM ETS - The AIRC Institute of Molecular Oncology, 20139 Milan, Italy
| | - Federica Di Nicolantonio
- Candiolo Cancer Institute, FPO-IRCCS, 10060 Candiolo, Italy; Department of Oncology, University of Torino, 10060 Candiolo, Italy
| | - David Lembo
- Department of Clinical and Biological Sciences, University of Torino, 10043 Orbassano, Italy
| | - Alberto Bardelli
- Department of Oncology, Molecular Biotechnology Center, University of Torino, Torino, Italy; IFOM ETS - The AIRC Institute of Molecular Oncology, 20139 Milan, Italy.
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3
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Altshuller M, He X, MacKrell EJ, Wernke KM, Wong JWH, Sellés-Baiget S, Wang TY, Chou TF, Duxin JP, Balskus EP, Herzon SB, Semlow DR. The Fanconi anemia pathway repairs colibactin-induced DNA interstrand cross-links. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.30.576698. [PMID: 38352618 PMCID: PMC10862771 DOI: 10.1101/2024.01.30.576698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
Colibactin is a secondary metabolite produced by bacteria present in the human gut and is implicated in the progression of colorectal cancer and inflammatory bowel disease. This genotoxin alkylates deoxyadenosines on opposite strands of host cell DNA to produce DNA interstrand cross-links (ICLs) that block DNA replication. While cells have evolved multiple mechanisms to resolve ("unhook") ICLs encountered by the replication machinery, little is known about which of these pathways promote resistance to colibactin-induced ICLs. Here, we use Xenopus egg extracts to investigate replication-coupled repair of plasmids engineered to contain site-specific colibactin-ICLs. We show that replication fork stalling at a colibactin-ICL leads to replisome disassembly and activation of the Fanconi anemia ICL repair pathway, which unhooks the colibactin-ICL through nucleolytic incisions. These incisions generate a DNA double-strand break intermediate in one sister chromatid, which can be repaired by homologous recombination, and a monoadduct ("ICL remnant") in the other. Our data indicate that translesion synthesis past the colibactin-ICL remnant depends on Polη and a Polκ-REV1-Polζ polymerase complex. Although translesion synthesis past colibactin-induced DNA damage is frequently error-free, it can introduce T>N point mutations that partially recapitulate the mutation signature associated with colibactin exposure in vivo. Taken together, our work provides a biochemical framework for understanding how cells tolerate a naturally-occurring and clinically-relevant ICL.
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Affiliation(s)
- Maria Altshuller
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Xu He
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Elliot J. MacKrell
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Kevin M. Wernke
- Department of Chemistry, Yale University, New Haven, CT, USA
| | - Joel W. H. Wong
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Selene Sellés-Baiget
- TheNovo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ting-Yu Wang
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- Proteome Exploration Laboratory, Beckman Institute, California Institute of Technology, Pasadena, CA, USA
| | - Tsui-Fen Chou
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- Proteome Exploration Laboratory, Beckman Institute, California Institute of Technology, Pasadena, CA, USA
| | - Julien P. Duxin
- TheNovo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Emily P. Balskus
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - Seth B. Herzon
- Department of Chemistry, Yale University, New Haven, CT, USA
| | - Daniel R. Semlow
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
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4
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Duizer C, de Zoete MR. The Role of Microbiota-Derived Metabolites in Colorectal Cancer. Int J Mol Sci 2023; 24:8024. [PMID: 37175726 PMCID: PMC10178193 DOI: 10.3390/ijms24098024] [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: 03/19/2023] [Revised: 04/25/2023] [Accepted: 04/25/2023] [Indexed: 05/15/2023] Open
Abstract
The impact of bacterial members of the microbiota on the development of colorectal cancer (CRC) has become clear in recent years. However, exactly how bacteria contribute to the development of cancer is often still up for debate. The impact of bacteria-derived metabolites, which can influence the development of CRC either in a promoting or inhibiting manner, is undeniable. Here, we discuss the effects of the most well-studied bacteria-derived metabolites associated with CRC, including secondary bile acids, short-chain fatty acids, trimethylamine-N-oxide and indoles. We show that the effects of individual metabolites on CRC development are often nuanced and dose- and location-dependent. In the coming years, the array of metabolites involved in CRC development will undoubtedly increase further, which will emphasize the need to focus on causation and mechanisms and the clearly defined roles of bacterial species within the microbiota.
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Affiliation(s)
| | - Marcel R. de Zoete
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
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5
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Velilla JA, Volpe MR, Kenney GE, Walsh RM, Balskus EP, Gaudet R. Structural basis of colibactin activation by the ClbP peptidase. Nat Chem Biol 2023; 19:151-158. [PMID: 36253550 PMCID: PMC9889268 DOI: 10.1038/s41589-022-01142-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 08/12/2022] [Indexed: 02/04/2023]
Abstract
Colibactin, a DNA cross-linking agent produced by gut bacteria, is implicated in colorectal cancer. Its biosynthesis uses a prodrug resistance mechanism: a non-toxic precursor assembled in the cytoplasm is activated after export to the periplasm. This activation is mediated by ClbP, an inner-membrane peptidase with an N-terminal periplasmic catalytic domain and a C-terminal three-helix transmembrane domain. Although the transmembrane domain is required for colibactin activation, its role in catalysis is unclear. Our structure of full-length ClbP bound to a product analog reveals an interdomain interface important for substrate binding and enzyme stability and interactions that explain the selectivity of ClbP for the N-acyl-D-asparagine prodrug motif. Based on structural and biochemical evidence, we propose that ClbP dimerizes to form an extended substrate-binding site that can accommodate a pseudodimeric precolibactin with its two terminal prodrug motifs in the two ClbP active sites, thus enabling the coordinated activation of both electrophilic warheads.
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Affiliation(s)
- José A Velilla
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Matthew R Volpe
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Grace E Kenney
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Richard M Walsh
- Harvard Cryo-EM Center for Structural Biology, Harvard Medical School, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Emily P Balskus
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - Rachelle Gaudet
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA.
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6
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Lin K, Gueble SE, Sundaram RK, Huseman ED, Bindra RS, Herzon SB. Mechanism-based design of agents that selectively target drug-resistant glioma. Science 2022; 377:502-511. [PMID: 35901163 PMCID: PMC9502022 DOI: 10.1126/science.abn7570] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Approximately half of glioblastoma and more than two-thirds of grade II and III glioma tumors lack the DNA repair protein O6-methylguanine methyl transferase (MGMT). MGMT-deficient tumors respond initially to the DNA methylation agent temozolomide (TMZ) but frequently acquire resistance through loss of the mismatch repair (MMR) pathway. We report the development of agents that overcome this resistance mechanism by inducing MMR-independent cell killing selectively in MGMT-silenced tumors. These agents deposit a dynamic DNA lesion that can be reversed by MGMT but slowly evolves into an interstrand cross-link in MGMT-deficient settings, resulting in MMR-independent cell death with low toxicity in vitro and in vivo. This discovery may lead to new treatments for gliomas and may represent a new paradigm for designing chemotherapeutics that exploit specific DNA repair defects.
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Affiliation(s)
- Kingson Lin
- Department of Chemistry, Yale University, New Haven, CT 06520, USA
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT 06520, USA
- Department of Pathology, Yale School of Medicine, New Haven, CT 06520, USA
| | - Susan E. Gueble
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT 06520, USA
| | - Ranjini K. Sundaram
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT 06520, USA
| | - Eric D. Huseman
- Department of Chemistry, Yale University, New Haven, CT 06520, USA
| | - Ranjit S. Bindra
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT 06520, USA
- Department of Pathology, Yale School of Medicine, New Haven, CT 06520, USA
- Corresponding author. (S.B.H.); (R.S.B.)
| | - Seth B. Herzon
- Department of Chemistry, Yale University, New Haven, CT 06520, USA
- Department of Pharmacology, Yale School of Medicine, New Haven, CT 06520, USA
- Corresponding author. (S.B.H.); (R.S.B.)
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7
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Abstract
Bacterial genotoxins are peptide or protein virulence factors produced by several pathogens, which make single-strand breaks (SSBs) and/or double-strand DNA breaks (DSBs) in the target host cells. If host DNA inflictions are not resolved on time, host cell apoptosis, cell senescence, and/or even bacterial pathogen-related cancer may occur. Two multi-protein AB toxins, cytolethal distending toxin (CDT) produced by over 30 bacterial pathogens and typhoid toxin from Salmonella Typhi, as well as small polyketide-peptides named colibactin that causes the DNA interstrand cross-linking and subsequent DSBs is the most well-characterized bacterial genotoxins. Using these three examples, this review discusses the mechanisms by which these toxins deliver themselves into the nucleus of the target host cells and exert their genotoxic functions at the structural and functional levels.
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Affiliation(s)
- Liaoqi Du
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA
| | - Jeongmin Song
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA
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8
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Hirayama Y, Sato M, Watanabe K. Advancing the Biosynthetic and Chemical Understanding of the Carcinogenic Risk Factor Colibactin and Its Producers. Biochemistry 2022; 61:2782-2790. [PMID: 35723977 DOI: 10.1021/acs.biochem.2c00229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Recent studies have shown that Escherichia coli often carries a biosynthetic gene cluster termed either the pks island or the clb cluster that allows the production of a genotoxic polyketide-nonribosomal peptide hybrid secondary metabolite called colibactin. While the gene cluster is not always expressed, when the strain that resides in the colon produces the genotoxin, it is suspected to become a risk factor for colorectal cancer. Therefore, there is great interest in devising a simple method for the detection of colibactin-producing strains and understanding the detailed mechanism of how colibactin can induce oncogenesis, to develop convenient early screening methods and possible preventive treatments against colorectal cancer. However, the definitive chemical structure of colibactin remained elusive until recently, primarily due to its low yield and instability. In this review, we will briefly trace the recent studies leading to the identification of the structure of the active intact colibactin. Subsequently, we will describe our efforts toward developing simple methods for detecting colibactin producers, where we established methods based on the conventional polymerase chain reaction and loop-mediated isothermal amplification techniques. We also designed an activity-based fluorogenic probe for detecting colibactin-producing strains that could discern colibactin production levels among the E. coli strains screened. Using the probe, we isolated a wild-type high-colibactin-producing strain from a colorectal cancer tissue sample that proved to be valuable in identifying new colibactin metabolites and structurally characterizing them by nuclear magnetic resonance. Those techniques and the chemical insight they furnished should improve the fight against colorectal cancer.
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Affiliation(s)
- Yuichiro Hirayama
- Department of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Tobetsu 061-0293, Japan
| | - Michio Sato
- Department of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526, Japan
| | - Kenji Watanabe
- Department of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526, Japan
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9
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Tang JW, Liu X, Ye W, Li ZR, Qian PY. Biosynthesis and bioactivities of microbial genotoxin colibactins. Nat Prod Rep 2022; 39:991-1014. [PMID: 35288725 DOI: 10.1039/d1np00050k] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Covering: up to 2021Colibactin(s), a group of secondary metabolites produced by the pks island (clb cluster) of Escherichia coli, shows genotoxicity relevant to colorectal cancer and thus significantly affects human health. Over the last 15 years, substantial efforts have been exerted to reveal the molecular structure of colibactin, but progress is slow owing to its instability, low titer, and elusive and complex biosynthesis logic. Fortunately, benefiting from the discovery of the prodrug mechanism, over 40 precursors of colibactin have been reported. Some key biosynthesis genes located on the pks island have also been characterised. Using an integrated bioinformatics, metabolomics, and chemical synthesis approach, researchers have recently characterised the structure and possible biosynthesis processes of colibactin, thereby providing new insights into the unique biosynthesis logic and the underlying mechanism of the biological activity of colibactin. Early developments in the study of colibactin have been summarised in several previous reviews covering various study periods, whereas the two most recent reviews have focused primarily on the chemical synthesis of colibactin. The present review aims to provide an update on the biosynthesis and bioactivities of colibactin.
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Affiliation(s)
- Jian-Wei Tang
- Department of Ocean Science, Hong Kong Branch of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China. .,Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou 511458, China
| | - Xin Liu
- Department of Ocean Science, Hong Kong Branch of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China. .,Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou 511458, China
| | - Wei Ye
- Department of Ocean Science, Hong Kong Branch of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China. .,State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Zhong-Rui Li
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Pei-Yuan Qian
- Department of Ocean Science, Hong Kong Branch of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China. .,Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou 511458, China
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10
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Nougayrède JP, Oswald E. Reply to Dubbert and von Bünau, "A Probiotic Friend". mSphere 2021; 6:e0090621. [PMID: 34935449 PMCID: PMC8694103 DOI: 10.1128/msphere.00906-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
| | - Eric Oswald
- IRSD, INSERM, INRAE, Université de Toulouse, ENVT, Toulouse, France
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11
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Tang-Fichaux M, Branchu P, Nougayrède JP, Oswald E. Tackling the Threat of Cancer Due to Pathobionts Producing Colibactin: Is Mesalamine the Magic Bullet? Toxins (Basel) 2021; 13:toxins13120897. [PMID: 34941734 PMCID: PMC8703417 DOI: 10.3390/toxins13120897] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 12/01/2021] [Accepted: 12/08/2021] [Indexed: 12/15/2022] Open
Abstract
Colibactin is a genotoxin produced primarily by Escherichia coli harboring the genomic pks island (pks+ E. coli). Pks+ E. coli cause host cell DNA damage, leading to chromosomal instability and gene mutations. The signature of colibactin-induced mutations has been described and found in human colorectal cancer (CRC) genomes. An inflamed intestinal environment drives the expansion of pks+ E. coli and promotes tumorigenesis. Mesalamine (i.e., 5-aminosalycilic acid), an effective anti-inflammatory drug, is an inhibitor of the bacterial polyphosphate kinase (PPK). This drug not only inhibits the production of intestinal inflammatory mediators and the proliferation of CRC cells, but also limits the abundance of E. coli in the gut microbiota and diminishes the production of colibactin. Here, we describe the link between intestinal inflammation and colorectal cancer induced by pks+ E. coli. We discuss the potential mechanisms of the pleiotropic role of mesalamine in treating both inflammatory bowel diseases and reducing the risk of CRC due to pks+ E. coli.
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Affiliation(s)
- Min Tang-Fichaux
- IRSD, Université de Toulouse, INSERM, INRAE, ENVT, UPS, 31024 Toulouse, France; (M.T.-F.); (P.B.); (J.-P.N.)
| | - Priscilla Branchu
- IRSD, Université de Toulouse, INSERM, INRAE, ENVT, UPS, 31024 Toulouse, France; (M.T.-F.); (P.B.); (J.-P.N.)
| | - Jean-Philippe Nougayrède
- IRSD, Université de Toulouse, INSERM, INRAE, ENVT, UPS, 31024 Toulouse, France; (M.T.-F.); (P.B.); (J.-P.N.)
| | - Eric Oswald
- IRSD, Université de Toulouse, INSERM, INRAE, ENVT, UPS, 31024 Toulouse, France; (M.T.-F.); (P.B.); (J.-P.N.)
- Service de Bactériology-Hygiène, Hôpital Purpan, CHU de Toulouse, 31059 Toulouse, France
- Correspondence:
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12
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Mezerová K, Starý L, Zbořil P, Klementa I, Stašek M, Špička P, Skalický P, Raclavský V. Cyclomodulins and Hemolysis in E. coli as Potential Low-Cost Non-Invasive Biomarkers for Colorectal Cancer Screening. Life (Basel) 2021; 11:1165. [PMID: 34833041 PMCID: PMC8621933 DOI: 10.3390/life11111165] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 10/01/2021] [Accepted: 10/29/2021] [Indexed: 12/18/2022] Open
Abstract
The frequent occurrence of E. coli positive for cyclomodulins such as colibactin (CLB), the cytotoxic necrotizing factor (CNF), and the cytolethal distending factor (CDT) in colorectal cancer (CRC) patients published so far provides the opportunity to use them as CRC screening markers. We examined the practicability and performance of a low-cost detection approach that relied on culture followed by simplified DNA extraction and PCR in E. coli isolates recovered from 130 CRC patients and 111 controls. Our results showed a statistically significant association between CRC and the presence of colibactin genes clbB and clbN, the cnf gene, and newly, the hemolytic phenotype of E. coli isolates. We also observed a significant increase in the mean number of morphologically distinct E. coli isolates per patient in the CRC cohort compared to controls, indicating that the cyclomodulin-producing E. coli strains may represent potentially preventable harmful newcomers in CRC patients. A colibactin gene assay showed the highest detection rate (45.4%), and males would benefit from the screening more than females. However, because of the high number of false positives, practical use of this marker must be explored. In our opinion, it may serve as an auxiliary marker to increase the specificity and/or sensitivity of the well-established fecal immunochemical test (FIT) in CRC screening.
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Affiliation(s)
- Kristýna Mezerová
- Department of Microbiology, Faculty of Medicine & Dentistry, Palacký University Olomouc, Hněvotínská 3, 775 15 Olomouc, Czech Republic;
| | - Lubomír Starý
- First Department of Surgery, University Hospital Olomouc, I. P. Pavlova 6, 779 00 Olomouc, Czech Republic; (L.S.); (P.Z.); (I.K.); (M.S.); (P.Š.); (P.S.)
| | - Pavel Zbořil
- First Department of Surgery, University Hospital Olomouc, I. P. Pavlova 6, 779 00 Olomouc, Czech Republic; (L.S.); (P.Z.); (I.K.); (M.S.); (P.Š.); (P.S.)
| | - Ivo Klementa
- First Department of Surgery, University Hospital Olomouc, I. P. Pavlova 6, 779 00 Olomouc, Czech Republic; (L.S.); (P.Z.); (I.K.); (M.S.); (P.Š.); (P.S.)
| | - Martin Stašek
- First Department of Surgery, University Hospital Olomouc, I. P. Pavlova 6, 779 00 Olomouc, Czech Republic; (L.S.); (P.Z.); (I.K.); (M.S.); (P.Š.); (P.S.)
| | - Petr Špička
- First Department of Surgery, University Hospital Olomouc, I. P. Pavlova 6, 779 00 Olomouc, Czech Republic; (L.S.); (P.Z.); (I.K.); (M.S.); (P.Š.); (P.S.)
| | - Pavel Skalický
- First Department of Surgery, University Hospital Olomouc, I. P. Pavlova 6, 779 00 Olomouc, Czech Republic; (L.S.); (P.Z.); (I.K.); (M.S.); (P.Š.); (P.S.)
| | - Vladislav Raclavský
- Department of Microbiology, Faculty of Medicine & Dentistry, Palacký University Olomouc, Hněvotínská 3, 775 15 Olomouc, Czech Republic;
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13
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Wernke KM, Tirla A, Xue M, Surovtseva YV, Menges FS, Herzon SB. Probing Microbiome Genotoxicity: A Stable Colibactin Provides Insight into Structure-Activity Relationships and Facilitates Mechanism of Action Studies. J Am Chem Soc 2021; 143:15824-15833. [PMID: 34524796 DOI: 10.1021/jacs.1c07559] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Colibactin is a genotoxic metabolite produced by commensal-pathogenic members of the human microbiome that possess the clb (aka pks) biosynthetic gene cluster. clb+ bacteria induce tumorigenesis in models of intestinal inflammation and have been causally linked to oncogenesis in humans. While colibactin is believed underlie these effects, it has not been possible to study the molecule directly due to its instability. Herein, we report the synthesis and biological studies of colibactin 742 (4), a stable colibactin derivative. We show that colibactin 742 (4) induces DNA interstrand-cross-links, activation of the Fanconi Anemia DNA repair pathway, and G2/M arrest in a manner similar to clb+E. coli. The linear precursor 9, which mimics the biosynthetic precursor to colibactin, also recapitulates the bacterial phenotype. In the course of this work, we discovered a novel cyclization pathway that was previously undetected in MS-based studies of colibactin, suggesting a refinement to the natural product structure and its mode of DNA binding. Colibactin 742 (4) and its precursor 9 will allow researchers to study colibactin's genotoxic effects independent of the producing organism for the first time.
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Affiliation(s)
- Kevin M Wernke
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Alina Tirla
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Mengzhao Xue
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Yulia V Surovtseva
- Yale Center for Molecular Discovery, Yale University, West Haven, Connecticut 06516, United States
| | - Fabian S Menges
- Chemical and Biophysical Instrumentation Center, Yale University, New Haven, Connecticut 06511, United States
| | - Seth B Herzon
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States.,Department of Pharmacology, Yale School of Medicine, New Haven, Connecticut 06520, United States
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14
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The Role of DNA Damage Response in Dysbiosis-Induced Colorectal Cancer. Cells 2021; 10:cells10081934. [PMID: 34440703 PMCID: PMC8391204 DOI: 10.3390/cells10081934] [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: 06/29/2021] [Revised: 07/23/2021] [Accepted: 07/23/2021] [Indexed: 12/16/2022] Open
Abstract
The high incidence of colorectal cancer (CRC) in developed countries indicates a predominant role of the environment as a causative factor. Natural gut microbiota provides multiple benefits to humans. Dysbiosis is characterized by an unbalanced microbiota and causes intestinal damage and inflammation. The latter is a common denominator in many cancers including CRC. Indeed, in an inflammation scenario, cellular growth is promoted and immune cells release Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS), which cause DNA damage. Apart from that, many metabolites from the diet are converted into DNA damaging agents by microbiota and some bacteria deliver DNA damaging toxins in dysbiosis conditions as well. The interactions between diet, microbiota, inflammation, and CRC are not the result of a straightforward relationship, but rather a network of multifactorial interactions that deserve deep consideration, as their consequences are not yet fully elucidated. In this paper, we will review the influence of dysbiosis in the induction of DNA damage and CRC.
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15
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Abstract
DNA interstrand cross-links (ICLs) covalently connect the two strands of the double helix and are extremely cytotoxic. Defective ICL repair causes the bone marrow failure and cancer predisposition syndrome, Fanconi anemia, and upregulation of repair causes chemotherapy resistance in cancer. The central event in ICL repair involves resolving the cross-link (unhooking). In this review, we discuss the chemical diversity of ICLs generated by exogenous and endogenous agents. We then describe how proliferating and nonproliferating vertebrate cells unhook ICLs. We emphasize fundamentally new unhooking strategies, dramatic progress in the structural analysis of the Fanconi anemia pathway, and insights into how cells govern the choice between different ICL repair pathways. Throughout, we highlight the many gaps that remain in our knowledge of these fascinating DNA repair pathways.
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Affiliation(s)
- Daniel R Semlow
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA; .,Current affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - Johannes C Walter
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA; .,Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
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16
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Zhou T, Hirayama Y, Tsunematsu Y, Suzuki N, Tanaka S, Uchiyama N, Goda Y, Yoshikawa Y, Iwashita Y, Sato M, Miyoshi N, Mutoh M, Ishikawa H, Sugimura H, Wakabayashi K, Watanabe K. Isolation of New Colibactin Metabolites from Wild-Type Escherichia coli and In Situ Trapping of a Mature Colibactin Derivative. J Am Chem Soc 2021; 143:5526-5533. [PMID: 33787233 DOI: 10.1021/jacs.1c01495] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Colibactin is a polyketide-nonribosomal peptide hybrid secondary metabolite that can form interstrand cross-links in double-stranded DNA. Colibactin-producing Escherichia coli has also been linked to colorectal oncogenesis. Thus, there is a strong interest in understanding the role colibactin may play in oncogenesis. Here, using the high-colibactin-producing wild-type E. coli strain we isolated from a clinical sample with the activity-based fluorescent probe we developed earlier, we were able to identify colibactin 770, which was recently identified and proposed as the complete form of colibactin, along with colibactin 788, 406, 416, 420, and 430 derived from colibactin 770 through structural rearrangements and solvolysis. Furthermore, we were able to trap the degrading mature colibactin species by converting the diketone moiety into quinoxaline in situ in the crude culture extract to form colibactin 860 at milligram scale. This allowed us to determine the stereochemically complex structure of the rearranged form of an intact colibactin, colibactin 788, in detail. Furthermore, our study suggested that we were capturing only a few percent of the actual colibactin produced by the microbe, providing a crude quantitative insight into the inherent instability of this compound. Through the structural assignment of colibactins and their degradative products by the combination of LC-HRMS and NMR spectroscopies, we were able to elucidate further the fate of inherently unstable colibactin, which could help acquire a more complete picture of colibactin metabolism and identify key DNA adducts and biomarkers for diagnosing colorectal cancer.
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Affiliation(s)
- Tao Zhou
- Adenoprevent Co., Ltd., Shizuoka 422-8526, Japan
- Department of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526, Japan
| | - Yuichiro Hirayama
- Department of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526, Japan
| | - Yuta Tsunematsu
- Department of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526, Japan
| | - Nanami Suzuki
- Department of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526, Japan
| | - Seiji Tanaka
- National Institute of Health Sciences, Kawasaki 210-9501, Japan
| | - Nahoko Uchiyama
- National Institute of Health Sciences, Kawasaki 210-9501, Japan
| | - Yukihiro Goda
- National Institute of Health Sciences, Kawasaki 210-9501, Japan
| | - Yuko Yoshikawa
- School of Veterinary Medicine, Faculty of Veterinary Science, Nippon Veterinary and Life Science University, Tokyo 180-8602, Japan
| | - Yuji Iwashita
- Department of Tumor Pathology, Hamamatsu University School of Medicine, Shizuoka 431-3192, Japan
| | - Michio Sato
- Department of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526, Japan
| | - Noriyuki Miyoshi
- Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka 422-8526, Japan
| | - Michihiro Mutoh
- Department of Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Hideki Ishikawa
- Department of Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Haruhiko Sugimura
- Department of Tumor Pathology, Hamamatsu University School of Medicine, Shizuoka 431-3192, Japan
| | - Keiji Wakabayashi
- Graduate Division of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka 422-8526, Japan
| | - Kenji Watanabe
- Adenoprevent Co., Ltd., Shizuoka 422-8526, Japan
- Department of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526, Japan
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17
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Iftekhar A, Berger H, Bouznad N, Heuberger J, Boccellato F, Dobrindt U, Hermeking H, Sigal M, Meyer TF. Genomic aberrations after short-term exposure to colibactin-producing E. coli transform primary colon epithelial cells. Nat Commun 2021; 12:1003. [PMID: 33579932 PMCID: PMC7881031 DOI: 10.1038/s41467-021-21162-y] [Citation(s) in RCA: 80] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 01/13/2021] [Indexed: 02/07/2023] Open
Abstract
Genotoxic colibactin-producing pks+ Escherichia coli induce DNA double-strand breaks, mutations, and promote tumor development in mouse models of colorectal cancer (CRC). Colibactin's distinct mutational signature is reflected in human CRC, suggesting a causal link. Here, we investigate its transformation potential using organoids from primary murine colon epithelial cells. Organoids recovered from short-term infection with pks+ E. coli show characteristics of CRC cells, e.g., enhanced proliferation, Wnt-independence, and impaired differentiation. Sequence analysis of Wnt-independent organoids reveals an enhanced mutational burden, including chromosomal aberrations typical of genomic instability. Although we do not find classic Wnt-signaling mutations, we identify several mutations in genes related to p53-signaling, including miR-34a. Knockout of Trp53 or miR-34 in organoids results in Wnt-independence, corroborating a functional interplay between the p53 and Wnt pathways. We propose larger chromosomal alterations and aneuploidy as the basis of transformation in these organoids, consistent with the early appearance of chromosomal instability in CRC.
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Affiliation(s)
- Amina Iftekhar
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Hilmar Berger
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany.,Laboratory of Infection Oncology, Institute of Clinical Molecular Biology, Christian Albrechts University of Kiel and University Hospital Schleswig Holstein - Campus Kiel, Kiel, Germany.,Department of Internal Medicine, Gastroenterology and Hepatology, Charité University Medicine, Berlin, Germany
| | - Nassim Bouznad
- Experimental and Molecular Pathology, Institute of Pathology, Ludwig Maximilians University, München, Germany
| | - Julian Heuberger
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany.,Department of Internal Medicine, Gastroenterology and Hepatology, Charité University Medicine, Berlin, Germany
| | - Francesco Boccellato
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany.,Ludwig Institute for Cancer Research, University of Oxford, Oxford, UK
| | - Ulrich Dobrindt
- Institute of Hygiene, University of Münster, Münster, Germany
| | - Heiko Hermeking
- Experimental and Molecular Pathology, Institute of Pathology, Ludwig Maximilians University, München, Germany.,German Cancer Consortium (DKTK), Partner Site München, München, Germany.,German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Michael Sigal
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany. .,Department of Internal Medicine, Gastroenterology and Hepatology, Charité University Medicine, Berlin, Germany. .,Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
| | - Thomas F Meyer
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany. .,Laboratory of Infection Oncology, Institute of Clinical Molecular Biology, Christian Albrechts University of Kiel and University Hospital Schleswig Holstein - Campus Kiel, Kiel, Germany.
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18
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Tang-Fichaux M, Chagneau CV, Bossuet-Greif N, Nougayrède JP, Oswald É, Branchu P. The Polyphosphate Kinase of Escherichia coli Is Required for Full Production of the Genotoxin Colibactin. mSphere 2020; 5:e01195-20. [PMID: 33328353 PMCID: PMC7771237 DOI: 10.1128/msphere.01195-20] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 11/24/2020] [Indexed: 12/15/2022] Open
Abstract
Colibactin induces DNA damage in mammalian cells and has been linked to the virulence of Escherichia coli and the promotion of colorectal cancer (CRC). By looking for mutants attenuated in the promoter activity of clbB encoding one of the key enzymes for the production of colibactin, we found that a mutant of the gene coding for the polyphosphate kinase (PPK) produced less colibactin than the parental strain. We observed this phenotype in different strains ranging from pathogens responsible for meningitis, urinary tract infection, or mouse colon carcinogenesis to the probiotic Nissle 1917. We confirmed the role of PPK by using an inhibitor of PPK enzymatic activity, mesalamine (also known as 5-aminosalicylic acid). Interestingly, mesalamine has a local anti-inflammatory effect on the epithelial cells of the colon and is used to treat inflammatory bowel disease (IBD). Upon treatment with mesalamine, a decreased genotoxicity of colibactin-producing E. coli was observed both on epithelial cells and directly on purified DNA. This demonstrates the direct effect of mesalamine on bacteria independently from its anti-inflammatory effect on eukaryotic cells. Our results suggest that the mechanisms of action of mesalamine in treating IBD and preventing CRC could also lie in the inhibition of colibactin production. All in all, we demonstrate that PPK is required for the promoter activity of clbB and the production of colibactin, which suggests that PPK is a promising target for the development of anticolibactin and antivirulence strategies.IMPORTANCE Colibactin-producing E. coli induces DNA damage in eukaryotic cells and promotes tumor formation in mouse models of intestinal inflammation. Recent studies have provided strong evidence supporting the causative role of colibactin in human colorectal cancer (CRC) progression. Therefore, it is important to understand the regulation of the production of this genotoxin. Here, we demonstrate that polyphosphate kinase (PPK) is required for the promoter activity of clbB and the production of colibactin. Interestingly, PPK is a multifunctional player in bacterial virulence and stress responses and has been proposed as a new target for developing antimicrobial medicine. We observed inhibition of colibactin production by using a previously identified PPK inhibitor (i.e., mesalamine, an anti-inflammatory drug commonly prescribed for inflammatory bowel diseases). These data brought us a new perspective on the regulatory network of colibactin production and provided us a clue for the development of anticolibactin strategies for CRC treatment/prophylaxis.
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Affiliation(s)
- Min Tang-Fichaux
- IRSD, Université de Toulouse, INSERM, INRAE, ENVT, UPS, Toulouse, France
| | - Camille V Chagneau
- IRSD, Université de Toulouse, INSERM, INRAE, ENVT, UPS, Toulouse, France
| | | | | | - Éric Oswald
- IRSD, Université de Toulouse, INSERM, INRAE, ENVT, UPS, Toulouse, France
- CHU Toulouse, Service de Bactériologie-Hygiène, Toulouse, France
| | - Priscilla Branchu
- IRSD, Université de Toulouse, INSERM, INRAE, ENVT, UPS, Toulouse, France
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19
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Colibactin DNA-damage signature indicates mutational impact in colorectal cancer. Nat Med 2020; 26:1063-1069. [PMID: 32483361 DOI: 10.1038/s41591-020-0908-2] [Citation(s) in RCA: 140] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 04/23/2020] [Indexed: 02/06/2023]
Abstract
The mucosal epithelium is a common target of damage by chronic bacterial infections and the accompanying toxins, and most cancers originate from this tissue. We investigated whether colibactin, a potent genotoxin1 associated with certain strains of Escherichia coli2, creates a specific DNA-damage signature in infected human colorectal cells. Notably, the genomic contexts of colibactin-induced DNA double-strand breaks were enriched for an AT-rich hexameric sequence motif, associated with distinct DNA-shape characteristics. A survey of somatic mutations at colibactin target sites of several thousand cancer genomes revealed notable enrichment of this motif in colorectal cancers. Moreover, the exact double-strand-break loci corresponded with mutational hot spots in cancer genomes, reminiscent of a trinucleotide signature previously identified in healthy colorectal epithelial cells3. The present study provides evidence for the etiological role of colibactin in human cancer.
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20
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Wernke KM, Xue M, Tirla A, Kim CS, Crawford JM, Herzon SB. Structure and bioactivity of colibactin. Bioorg Med Chem Lett 2020; 30:127280. [PMID: 32527463 DOI: 10.1016/j.bmcl.2020.127280] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 05/16/2020] [Accepted: 05/18/2020] [Indexed: 12/27/2022]
Abstract
Colibactin is a secondary metabolite produced by certain strains of bacteria found in the human gut. The presence of colibactin-producing bacteria has been correlated to colorectal cancer in humans. Colibactin was first discovered in 2006, but because it is produced in small quantities and is unstable, it has yet to be isolated from bacterial cultures. Here we summarize advances in the field since ~2017 that have led to the identification of the structure of colibactin as a heterodimer containing two DNA-reactive electrophilic cyclopropane residues. Colibactin has been shown to form interstrand cross-links by alkylation of adenine residues on opposing strands of DNA. The structure of colibactin contains two thiazole rings separated by a two-carbon linker that is thought to exist as an α-aminoketone following completion of the biosynthetic pathway. However, synthetic studies have now established that this α-aminoketone is unstable toward aerobic oxidation; the resulting oxidation products are in turn unstable toward nucleophilic cleavage under mild conditions. These data provide a simple molecular-level explanation for colibactin's instability and potentially also explain the observation that cell-to-cell contact is required for genotoxic effects.
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Affiliation(s)
- Kevin M Wernke
- Department of Chemistry, Yale University, New Haven, CT 06520, United States
| | - Mengzhao Xue
- Department of Chemistry, Yale University, New Haven, CT 06520, United States
| | - Alina Tirla
- Department of Chemistry, Yale University, New Haven, CT 06520, United States
| | - Chung Sub Kim
- Department of Chemistry, Yale University, New Haven, CT 06520, United States; Chemical Biology Institute, Yale University, West Haven, CT 06516, United States
| | - Jason M Crawford
- Department of Chemistry, Yale University, New Haven, CT 06520, United States; Chemical Biology Institute, Yale University, West Haven, CT 06516, United States; Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT 06536, United States
| | - Seth B Herzon
- Department of Chemistry, Yale University, New Haven, CT 06520, United States; Department of Pharmacology, Yale School of Medicine, New Haven, CT 06520, United States.
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