1
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Ruiz-Albor A, Chaves-Arquero B, Martín-Barros I, Guerra-Castellano A, Gonzalez-Magaña A, de Opakua AI, Merino N, Ferreras-Gutiérrez M, Berra E, Díaz-Moreno I, Blanco FJ. PCNA molecular recognition of different PIP motifs: Role of Tyr211 phosphorylation. Int J Biol Macromol 2024:133187. [PMID: 38880460 DOI: 10.1016/j.ijbiomac.2024.133187] [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: 05/06/2024] [Revised: 06/11/2024] [Accepted: 06/13/2024] [Indexed: 06/18/2024]
Abstract
The coordination of enzymes and regulatory proteins for eukaryotic DNA replication and repair is largely achieved by Proliferating Cell Nuclear Antigen (PCNA), a toroidal homotrimeric protein that embraces the DNA duplex. Many proteins bind PCNA through a conserved sequence known as the PCNA interacting protein motif (PIP). PCNA is further regulated by different post-translational modifications. Phosphorylation at residue Y211 facilitates unlocking stalled replication forks to bypass DNA damage repair processes but increasing nucleotide misincorporation. We explore here how phosphorylation at Y211 affects PCNA recognition of the canonical PIP sequences of the regulatory proteins p21 and p15, which bind with nM and μM affinity, respectively. For that purpose, PCNA with p-carboxymethyl-L-phenylalanine (pCMF), a mimetic of phosphorylated tyrosine at position 211 was prepared. We have also characterized PCNA binding to the non-canonical PIP sequence of the catalytic subunit of DNA polymerase δ (p125), and to the canonical PIP sequence of the enzyme ubiquitin specific peptidase 29 (USP29) which deubiquitinates PCNA. Our results show that Tyr211 phosphorylation has little effect on the molecular recognition of p21 and p15, and that the PIP sequences of p125 and USP29 bind to the same site on PCNA as other PIP sequences, but with very low affinity.
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Affiliation(s)
- Antonio Ruiz-Albor
- Centro de Investigaciones Biológicas Margarita Salas (CIB), CSIC, Madrid 28040, Spain
| | - Belén Chaves-Arquero
- Centro de Investigaciones Biológicas Margarita Salas (CIB), CSIC, Madrid 28040, Spain
| | | | | | | | | | | | | | | | - Irene Díaz-Moreno
- Instituto de Investigaciones Químicas, cicCartuja, Universidad de Sevilla-CSIC, Sevilla, Spain
| | - Francisco J Blanco
- Centro de Investigaciones Biológicas Margarita Salas (CIB), CSIC, Madrid 28040, Spain.
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2
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Zheng R, Su R, Fan Y, Xing F, Huang K, Yan F, Chen H, Liu B, Fang L, Du Y, Zhou F, Wang D, Feng S. Machine Learning-Based Integrated Multiomics Characterization of Colorectal Cancer Reveals Distinctive Metabolic Signatures. Anal Chem 2024; 96:8772-8781. [PMID: 38743842 DOI: 10.1021/acs.analchem.4c01171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
The metabolic signature identification of colorectal cancer is critical for its early diagnosis and therapeutic approaches that will significantly block cancer progression and improve patient survival. Here, we combined an untargeted metabolic analysis strategy based on internal extractive electrospray ionization mass spectrometry and the machine learning approach to analyze metabolites in 173 pairs of cancer samples and matched normal tissue samples to build robust metabolic signature models for diagnostic purposes. Screening and independent validation of metabolic signatures from colorectal cancers via machine learning methods (Logistic Regression_L1 for feature selection and eXtreme Gradient Boosting for classification) was performed to generate a panel of seven signatures with good diagnostic performance (the accuracy of 87.74%, sensitivity of 85.82%, and specificity of 89.66%). Moreover, seven signatures were evaluated according to their ability to distinguish between cancer and normal tissues, with the metabolic molecule PC (30:0) showing good diagnostic performance. In addition, genes associated with PC (30:0) were identified by multiomics analysis (combining metabolic data with transcriptomic data analysis) and our results showed that PC (30:0) could promote the proliferation of colorectal cancer cell SW480, revealing the correlation between genetic changes and metabolic dysregulation in cancer. Overall, our results reveal potential determinants affecting metabolite dysregulation, paving the way for a mechanistic understanding of altered tissue metabolites in colorectal cancer and design interventions for manipulating the levels of circulating metabolites.
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Affiliation(s)
- Ran Zheng
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130021, China
| | - Rui Su
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130021, China
| | - Yusi Fan
- Key Laboratory of Symbolic Computation and Knowledge Engineering of Ministry of Education, College of Software, Jilin University, Changchun 130021, China
| | - Fan Xing
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130021, China
| | - Keke Huang
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130021, China
| | - Fei Yan
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130021, China
| | - Huanwen Chen
- School of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang 330004, China
| | - Botong Liu
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130021, China
| | - Laiping Fang
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130021, China
| | - Yechao Du
- Department of General Surgery Center, First Hospital of Jilin University, 1 Xinmin Street Changchun, Jilin 130012, China
| | - Fengfeng Zhou
- Key Laboratory of Symbolic Computation and Knowledge Engineering of Ministry of Education, College of Software, Jilin University, Changchun 130021, China
| | - Daguang Wang
- Department of Gastric Colorectal and Anal Surgery, First Hospital of Jilin University, 1 Xinmin Street Changchun, Jilin 130012, China
| | - Shouhua Feng
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130021, China
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3
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Chengcheng L, Raza SHA, Zhimei Y, Sihu W, Shengchen Y, Aloufi BH, Bingzhi L, Zan L. Bta-miR-181d and Bta-miR-196a mediated proliferation, differentiation, and apoptosis in Bovine Myogenic Cells. J Anim Sci 2024; 102:skae142. [PMID: 38766769 PMCID: PMC11161902 DOI: 10.1093/jas/skae142] [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: 11/21/2023] [Accepted: 05/17/2024] [Indexed: 05/22/2024] Open
Abstract
Skeletal muscle is an important component of livestock and poultry organisms. The proliferation and differentiation of myoblasts are highly coordinated processes, which rely on the regulation of miRNA. MiRNAs are widely present in organisms and play roles in various biological processes, including cell proliferation, differentiation, and apoptosis. MiR-181d and miR-196a, identified as tumor suppressors, have been found to be involved in cell proliferation, apoptosis, directed differentiation, and cancer cell invasion. However, their role in beef cattle skeletal muscle metabolism remains unclear. In this study, we discovered that overexpression of bta-miR-181d and bta-miR-196a in Qinchuan cattle myoblasts inhibited proliferation and apoptosis while promoting myogenic differentiation through EDU staining, flow cytometry analysis, immunofluorescence staining, and Western blotting. RNA-seq analysis of differential gene expression revealed that after overexpression of bta-miR-181d and bta-miR-196a, the differentially expressed genes were mainly enriched in the PI3K-Akt and MAPK signaling pathways. Furthermore, the phosphorylation levels of key proteins p-AKT in the PI3K signaling pathway and p-MAPK in the MAPK signaling pathway were significantly decreased after overexpression of bta-miR-181d and bta-miR-196a. Overall, this study provides preliminary evidence that bta-miR-181d and bta-miR-196a may regulate proliferation, apoptosis, and differentiation processes in Qinchuan cattle myoblasts by affecting the phosphorylation status of key proteins in PI3K-Akt and MAPK-ERK signaling pathways.
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Affiliation(s)
- Liang Chengcheng
- College of Animal Science and Technology, Xinyang Agriculture and Forestry University, Xinyang, Henan 464000, P.R. China
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, P.R. China
| | - Sayed Haidar Abbas Raza
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, P.R. China
- Guangdong Provincial Key Laboratory of Food Quality and Safety/Nation-Local Joint Engineering Research Center for Machining and Safety of Livestock and Poultry Products, South China Agricultural University, Guangzhou 510642, P.R. China
| | - Yang Zhimei
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, P.R. China
| | - Wang Sihu
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, P.R. China
| | - Yu Shengchen
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, P.R. China
| | - Bandar Hamad Aloufi
- Biology Department, Faculty of Science, University of Ha'il, Ha'il, Saudi Arabia
| | - Li Bingzhi
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, P.R. China
| | - Linsen Zan
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, P.R. China
- National Beef Cattle Improvement Center, Northwest A&F University, Yangling, 712100, China
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4
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Magrino J, Munford V, Martins DJ, Homma TK, Page B, Gaubitz C, Freire BL, Lerario AM, Vilar JB, Amorin A, Leão EKE, Kok F, Menck CF, Jorge AA, Kelch BA. A thermosensitive PCNA allele underlies an ataxia-telangiectasia-like disorder. J Biol Chem 2023; 299:104656. [PMID: 36990216 PMCID: PMC10165274 DOI: 10.1016/j.jbc.2023.104656] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 02/25/2023] [Accepted: 03/10/2023] [Indexed: 03/29/2023] Open
Abstract
Proliferating cell nuclear antigen (PCNA) is a sliding clamp protein that coordinates DNA replication with various DNA maintenance events that are critical for human health. Recently, a hypomorphic homozygous serine to isoleucine (S228I) substitution in PCNA was described to underlie a rare DNA repair disorder known as PCNA-associated DNA repair disorder (PARD). PARD symptoms range from UV sensitivity, neurodegeneration, telangiectasia, and premature aging. We, and others, previously showed that the S228I variant changes the protein-binding pocket of PCNA to a conformation that impairs interactions with specific partners. Here, we report a second PCNA substitution (C148S) that also causes PARD. Unlike PCNA-S228I, PCNA-C148S has WT-like structure and affinity toward partners. In contrast, both disease-associated variants possess a thermostability defect. Furthermore, patient-derived cells homozygous for the C148S allele exhibit low levels of chromatin-bound PCNA and display temperature-dependent phenotypes. The stability defect of both PARD variants indicates that PCNA levels are likely an important driver of PARD disease. These results significantly advance our understanding of PARD and will likely stimulate additional work focused on clinical, diagnostic, and therapeutic aspects of this severe disease.
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Affiliation(s)
- Joseph Magrino
- Department of Biochemistry and Biotechnology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Veridiana Munford
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Davi Jardim Martins
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Thais K Homma
- Genetic Endocrinology Unit, Cellular and Molecular Endocrinology Laboratory LIM25, Endocrinology Discipline of the Faculty of Medicine of the University of São Paulo, São Paulo, Brazil; Developmental Endocrinology Unit, Laboratory of Hormones and Molecular Genetics LIM42, Faculty of Medicine of the University of São Paulo, São Paulo, Brazil
| | - Brendan Page
- Department of Biochemistry and Biotechnology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Christl Gaubitz
- Department of Biochemistry and Biotechnology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Bruna L Freire
- Genetic Endocrinology Unit, Cellular and Molecular Endocrinology Laboratory LIM25, Endocrinology Discipline of the Faculty of Medicine of the University of São Paulo, São Paulo, Brazil; Developmental Endocrinology Unit, Laboratory of Hormones and Molecular Genetics LIM42, Faculty of Medicine of the University of São Paulo, São Paulo, Brazil
| | - Antonio M Lerario
- Developmental Endocrinology Unit, Laboratory of Hormones and Molecular Genetics LIM42, Faculty of Medicine of the University of São Paulo, São Paulo, Brazil; Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, University of Michigan, Ann Arbor, Michigan, USA
| | - Juliana Brandstetter Vilar
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Antonio Amorin
- Neurogenetics, Neurology Department, Faculty of Medicine of the University of São Paulo, São Paulo, Brazil
| | - Emília K E Leão
- Medical Genetics Service of the Professor Edgard Santos University Hospital - Federal University of Bahia, Salvador, Brazil
| | - Fernando Kok
- Neurogenetics, Neurology Department, Faculty of Medicine of the University of São Paulo, São Paulo, Brazil; Mendelics Genomic Analysis, São Paulo, São Paulo, Brazil
| | - Carlos Fm Menck
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Alexander Al Jorge
- Genetic Endocrinology Unit, Cellular and Molecular Endocrinology Laboratory LIM25, Endocrinology Discipline of the Faculty of Medicine of the University of São Paulo, São Paulo, Brazil
| | - Brian A Kelch
- Department of Biochemistry and Biotechnology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA.
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5
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Kim S, Kim Y, Kim Y, Yoon S, Lee KY, Lee Y, Kang S, Myung K, Oh CK. PCNA Ser46-Leu47 residues are crucial in preserving genomic integrity. PLoS One 2023; 18:e0285337. [PMID: 37205694 DOI: 10.1371/journal.pone.0285337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 04/19/2023] [Indexed: 05/21/2023] Open
Abstract
Proliferating cell nuclear antigen (PCNA) is a maestro of DNA replication. PCNA forms a homotrimer and interacts with various proteins, such as DNA polymerases, DNA ligase I (LIG1), and flap endonuclease 1 (FEN1) for faithful DNA replication. Here, we identify the crucial role of Ser46-Leu47 residues of PCNA in maintaining genomic integrity using in vitro, and cell-based assays and structural prediction. The predicted PCNAΔSL47 structure shows the potential distortion of the central loop and reduced hydrophobicity. PCNAΔSL47 shows a defective interaction with PCNAWT leading to defects in homo-trimerization in vitro. PCNAΔSL47 is defective in the FEN1 and LIG1 interaction. PCNA ubiquitination and DNA-RNA hybrid processing are defective in PCNAΔSL47-expressing cells. Accordingly, PCNAΔSL47-expressing cells exhibit an increased number of single-stranded DNA gaps and higher levels of γH2AX, and sensitivity to DNA-damaging agents, highlighting the importance of PCNA Ser46-Leu47 residues in maintaining genomic integrity.
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Affiliation(s)
- Sangin Kim
- Institute for Basic Science, Center for Genomic Integrity, Ulsan, Korea
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, College of Information-Bio Convergence Engineering, Ulsan, Korea
| | - Yeongjae Kim
- Institute for Basic Science, Center for Genomic Integrity, Ulsan, Korea
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, College of Information-Bio Convergence Engineering, Ulsan, Korea
| | - Youyoung Kim
- Institute for Basic Science, Center for Genomic Integrity, Ulsan, Korea
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, College of Information-Bio Convergence Engineering, Ulsan, Korea
| | - Suhyeon Yoon
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Integrated Data Sciences Section, Research Technologies Branch, Bethesda, MD, United States of America
| | - Kyoo-Young Lee
- Institute for Basic Science, Center for Genomic Integrity, Ulsan, Korea
- Department of Biochemistry, College of Medicine, Hallym University, Chuncheon, Gangwon-do, Korea
| | - Yoonsung Lee
- Clinical Research Institute, Kyung Hee University Hospital at Gangdong, College of Medicine, Kyung Hee University, Seoul, Korea
| | - Sukhyun Kang
- Institute for Basic Science, Center for Genomic Integrity, Ulsan, Korea
| | - Kyungjae Myung
- Institute for Basic Science, Center for Genomic Integrity, Ulsan, Korea
- Ulsan National Institute of Science and Technology, Department of Biomedical Engineering, College of Information-Bio Convergence Engineering, Ulsan, Korea
| | - Chang-Kyu Oh
- Department of Biochemistry, Pusan National University, School of Medicine, Yangsan, Korea
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6
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Daniels HG, Knicely BG, Miller AK, Thompson A, Plattner R, Goellner EM. Inhibition of ABL1 by tyrosine kinase inhibitors leads to a downregulation of MLH1 by Hsp70-mediated lysosomal protein degradation. Front Genet 2022; 13:940073. [PMID: 36338985 PMCID: PMC9631443 DOI: 10.3389/fgene.2022.940073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 10/03/2022] [Indexed: 01/07/2023] Open
Abstract
The DNA mismatch repair (MMR) pathway and its regulation are critical for genomic stability. Mismatch repair (MMR) follows replication and repairs misincorporated bases and small insertions or deletions that are not recognized and removed by the proofreading polymerase. Cells deficient in MMR exhibit an increased overall mutation rate and increased expansion and contraction of short repeat sequences in the genome termed microsatellite instability (MSI). MSI is often a clinical measure of genome stability in tumors and is used to determine the course of treatment. MMR is also critical for inducing apoptosis after alkylation damage from environmental agents or DNA-damaging chemotherapy. MLH1 is essential for MMR, and loss or mutation of MLH1 leads to defective MMR, increased mutation frequency, and MSI. In this study, we report that tyrosine kinase inhibitors, imatinib and nilotinib, lead to decreased MLH1 protein expression but not decreased MLH1 mRNA levels. Of the seven cellular targets of Imatinib and nilotinib, we show that silencing of ABL1 also reduces MLH1 protein expression. Treatment with tyrosine kinase inhibitors or silencing of ABL1 results in decreased apoptosis after treatment with alkylating agents, suggesting the level of MLH1 reduction is sufficient to disrupt MMR function. We also report MLH1 is tyrosine phosphorylated by ABL1. We demonstrate that MLH1 downregulation by ABL1 knockdown or inhibition requires chaperone protein Hsp70 and that MLH1 degradation can be abolished with the lysosomal inhibitor bafilomycin. Taken together, we propose that ABL1 prevents MLH1 from being targeted for degradation by the chaperone Hsp70 and that in the absence of ABL1 activity at least a portion of MLH1 is degraded through the lysosome. This study represents an advance in understanding MMR pathway regulation and has important clinical implications as MMR status is used in the clinic to inform patient treatment, including the use of immunotherapy.
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Affiliation(s)
- Hannah G. Daniels
- University of Kentucky, College of Medicine Department of Toxicology and Cancer Biology, Lexington, KY, United States
| | - Breanna G. Knicely
- University of Kentucky, College of Medicine Department of Toxicology and Cancer Biology, Lexington, KY, United States
| | - Anna Kristin Miller
- University of Kentucky, College of Medicine Department of Toxicology and Cancer Biology, Lexington, KY, United States
| | - Ana Thompson
- Berea College, Berea, KY, United States,University of Kentucky Markey Cancer Center, Lexington, KY, United States
| | - Rina Plattner
- University of Kentucky Markey Cancer Center, Lexington, KY, United States,University of Kentucky, College of Medicine Department of Pharmacology and Nutritional Sciences, Lexington, KY, United States
| | - Eva M. Goellner
- University of Kentucky, College of Medicine Department of Toxicology and Cancer Biology, Lexington, KY, United States,University of Kentucky Markey Cancer Center, Lexington, KY, United States,*Correspondence: Eva M. Goellner,
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7
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Tam LKB, He L, Ng DKP, Cheung PCK, Lo P. A Tumor‐Targeting Dual‐Stimuli‐Activatable Photodynamic Molecular Beacon for Precise Photodynamic Therapy. Chemistry 2022; 28:e202201652. [DOI: 10.1002/chem.202201652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Indexed: 11/07/2022]
Affiliation(s)
- Leo K. B. Tam
- Department of Chemistry The Chinese University of Hong Kong Shatin, N. T. Hong Kong China
| | - Lin He
- Department of Biomedical Sciences City University of Hong Kong Tat Chee Avenue, Kowloon Hong Kong China
| | - Dennis K. P. Ng
- Department of Chemistry The Chinese University of Hong Kong Shatin, N. T. Hong Kong China
| | - Peter C. K. Cheung
- School of Life Sciences The Chinese University of Hong Kong Shatin, N. T. Hong Kong China
| | - Pui‐Chi Lo
- Department of Biomedical Sciences City University of Hong Kong Tat Chee Avenue, Kowloon Hong Kong China
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8
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Post-Translational Modifications of PCNA: Guiding for the Best DNA Damage Tolerance Choice. J Fungi (Basel) 2022; 8:jof8060621. [PMID: 35736104 PMCID: PMC9225081 DOI: 10.3390/jof8060621] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 06/01/2022] [Accepted: 06/07/2022] [Indexed: 02/01/2023] Open
Abstract
The sliding clamp PCNA is a multifunctional homotrimer mainly linked to DNA replication. During this process, cells must ensure an accurate and complete genome replication when constantly challenged by the presence of DNA lesions. Post-translational modifications of PCNA play a crucial role in channeling DNA damage tolerance (DDT) and repair mechanisms to bypass unrepaired lesions and promote optimal fork replication restart. PCNA ubiquitination processes trigger the following two main DDT sub-pathways: Rad6/Rad18-dependent PCNA monoubiquitination and Ubc13-Mms2/Rad5-mediated PCNA polyubiquitination, promoting error-prone translation synthesis (TLS) or error-free template switch (TS) pathways, respectively. However, the fork protection mechanism leading to TS during fork reversal is still poorly understood. In contrast, PCNA sumoylation impedes the homologous recombination (HR)-mediated salvage recombination (SR) repair pathway. Focusing on Saccharomyces cerevisiae budding yeast, we summarized PCNA related-DDT and repair mechanisms that coordinately sustain genome stability and cell survival. In addition, we compared PCNA sequences from various fungal pathogens, considering recent advances in structural features. Importantly, the identification of PCNA epitopes may lead to potential fungal targets for antifungal drug development.
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9
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Lynch-like Syndrome: Potential Mechanisms and Management. Cancers (Basel) 2022; 14:cancers14051115. [PMID: 35267422 PMCID: PMC8909420 DOI: 10.3390/cancers14051115] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 02/20/2022] [Accepted: 02/21/2022] [Indexed: 02/05/2023] Open
Abstract
Simple Summary Lynch-like syndrome (LLS) is defined as colorectal cancer cases with microsatellite instability (MSI) and loss of expression of MLH1, MSH2, MSH6, or PMS2 by immunohistochemistry (IHC) in the absence of a germline mutation in these genes that cannot be explained by BRAF mutation or MLH1 hypermethylation. The application of the universal strategy for the diagnosis of Lynch syndrome (LS) in all CRCs is leading to an increase in the incidence of cases of LLS. It has been described that risk of cancer in relatives of LLS patients is in between of that found in Lynch syndrome families and sporadic cases. That makes LLS patients and their families a challenging group for which the origin of CRC is unknown, being a mixture between unidentified hereditary CRC and sporadic cases. The potential causes of LLS are discussed in this review, as well as methods for identification of truly hereditary cases. Abstract Lynch syndrome is an autosomal dominant disorder caused by germline mutations in DNA mismatch repair (MMR) system genes, such as MLH1, MSH2, MSH6, or PMS2. It is the most common hereditary colorectal cancer syndrome. Screening is regularly performed by using microsatellite instability (MSI) or immunohistochemistry for the MMR proteins in tumor samples. However, in a proportion of cases, MSI is found or MMR immunohistochemistry is impaired in the absence of a germline mutation in MMR genes, BRAF mutation, or MLH1 hypermethylation. These cases are defined as Lynch-like syndrome. Patients with Lynch-like syndrome represent a mixture of truly hereditary and sporadic cases, with a risk of colorectal cancer in first-degree relatives that is between the risk of Lynch syndrome in families and relatives of sporadic colon cancer cases. Although multiple approaches have been suggested to distinguish between hereditary and sporadic cases, a homogeneous testing protocol and consensus on the adequate classification of these patients is still lacking. For this reason, management of Lynch-like syndrome and prevention of cancer in these families is clinically challenging. This review explains the concept of Lynch-like syndrome, potential mechanisms for its development, and methods for adequately distinguishing between sporadic and hereditary cases of this entity.
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10
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Guervilly JH, Blin M, Laureti L, Baudelet E, Audebert S, Gaillard PH. SLX4 dampens MutSα-dependent mismatch repair. Nucleic Acids Res 2022; 50:2667-2680. [PMID: 35166826 PMCID: PMC8934664 DOI: 10.1093/nar/gkac075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 01/20/2022] [Accepted: 01/25/2022] [Indexed: 12/12/2022] Open
Abstract
The tumour suppressor SLX4 plays multiple roles in the maintenance of genome stability, acting as a scaffold for structure-specific endonucleases and other DNA repair proteins. It directly interacts with the mismatch repair (MMR) protein MSH2 but the significance of this interaction remained unknown until recent findings showing that MutSβ (MSH2-MSH3) stimulates in vitro the SLX4-dependent Holliday junction resolvase activity. Here, we characterize the mode of interaction between SLX4 and MSH2, which relies on an MSH2-interacting peptide (SHIP box) that drives interaction of SLX4 with both MutSβ and MutSα (MSH2-MSH6). While we show that this MSH2 binding domain is dispensable for the well-established role of SLX4 in interstrand crosslink repair, we find that it mediates inhibition of MutSα-dependent MMR by SLX4, unravelling an unanticipated function of SLX4.
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Affiliation(s)
- Jean-Hugues Guervilly
- Centre de Recherche en Cancérologie de Marseille, CRCM, Inserm, CNRS, Aix-Marseille Université, Institut Paoli-Calmettes, Marseille, France
| | - Marion Blin
- Centre de Recherche en Cancérologie de Marseille, CRCM, Inserm, CNRS, Aix-Marseille Université, Institut Paoli-Calmettes, Marseille, France
| | - Luisa Laureti
- Centre de Recherche en Cancérologie de Marseille, CRCM, Inserm, CNRS, Aix-Marseille Université, Institut Paoli-Calmettes, Marseille, France
| | - Emilie Baudelet
- Centre de Recherche en Cancérologie de Marseille, CRCM, Inserm, CNRS, Aix-Marseille Université, Institut Paoli-Calmettes, Marseille, France
| | - Stéphane Audebert
- Centre de Recherche en Cancérologie de Marseille, CRCM, Inserm, CNRS, Aix-Marseille Université, Institut Paoli-Calmettes, Marseille, France
| | - Pierre-Henri Gaillard
- Centre de Recherche en Cancérologie de Marseille, CRCM, Inserm, CNRS, Aix-Marseille Université, Institut Paoli-Calmettes, Marseille, France
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11
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Zhou X, Speer RM, Volk L, Hudson LG, Liu KJ. Arsenic co-carcinogenesis: Inhibition of DNA repair and interaction with zinc finger proteins. Semin Cancer Biol 2021; 76:86-98. [PMID: 33984503 PMCID: PMC8578584 DOI: 10.1016/j.semcancer.2021.05.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/05/2021] [Accepted: 05/06/2021] [Indexed: 12/17/2022]
Abstract
Arsenic is widely present in the environment and is associated with various population health risks including cancers. Arsenic exposure at environmentally relevant levels enhances the mutagenic effect of other carcinogens such as ultraviolet radiation. Investigation on the molecular mechanisms could inform the prevention and intervention strategies of arsenic carcinogenesis and co-carcinogenesis. Arsenic inhibition of DNA repair has been demonstrated to be an important mechanism, and certain DNA repair proteins have been identified to be extremely sensitive to arsenic exposure. This review will summarize the recent advances in understanding the mechanisms of arsenic carcinogenesis and co-carcinogenesis, including DNA damage induction and ROS generation, particularly how arsenic inhibits DNA repair through an integrated molecular mechanism which includes its interactions with sensitive zinc finger DNA repair proteins.
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Affiliation(s)
- Xixi Zhou
- Department of Pharmaceutical Sciences, University of New Mexico Health Sciences Center, Albuquerque, NM, 87131, USA
| | - Rachel M Speer
- Department of Pharmaceutical Sciences, University of New Mexico Health Sciences Center, Albuquerque, NM, 87131, USA
| | - Lindsay Volk
- Department of Pharmaceutical Sciences, University of New Mexico Health Sciences Center, Albuquerque, NM, 87131, USA
| | - Laurie G Hudson
- Department of Pharmaceutical Sciences, University of New Mexico Health Sciences Center, Albuquerque, NM, 87131, USA.
| | - Ke Jian Liu
- Department of Pharmaceutical Sciences, University of New Mexico Health Sciences Center, Albuquerque, NM, 87131, USA.
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12
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Wang Y, Chen Y, Wang C, Yang M, Wang Y, Bao L, Wang JE, Kim B, Chan KY, Xu W, Capota E, Ortega J, Nijhawan D, Li GM, Luo W, Wang Y. MIF is a 3' flap nuclease that facilitates DNA replication and promotes tumor growth. Nat Commun 2021; 12:2954. [PMID: 34012010 PMCID: PMC8134555 DOI: 10.1038/s41467-021-23264-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Accepted: 04/20/2021] [Indexed: 11/13/2022] Open
Abstract
How cancer cells cope with high levels of replication stress during rapid proliferation is currently unclear. Here, we show that macrophage migration inhibitory factor (MIF) is a 3’ flap nuclease that translocates to the nucleus in S phase. Poly(ADP-ribose) polymerase 1 co-localizes with MIF to the DNA replication fork, where MIF nuclease activity is required to resolve replication stress and facilitates tumor growth. MIF loss in cancer cells leads to mutation frequency increases, cell cycle delays and DNA synthesis and cell growth inhibition, which can be rescued by restoring MIF, but not nuclease-deficient MIF mutant. MIF is significantly upregulated in breast tumors and correlates with poor overall survival in patients. We propose that MIF is a unique 3’ nuclease, excises flaps at the immediate 3’ end during DNA synthesis and favors cancer cells evading replication stress-induced threat for their growth. Replication stress is associated with cancer formation and progression. Here the authors reveal that the macrophage migration inhibitory factor (MIF) functions as 3’ flap nuclease involved in resolving replication stress affecting overall tumor progression.
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Affiliation(s)
- Yijie Wang
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Yan Chen
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Chenliang Wang
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Mingming Yang
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Yanan Wang
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Lei Bao
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Jennifer E Wang
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, USA
| | - BongWoo Kim
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Kara Y Chan
- Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Weizhi Xu
- Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Emanuela Capota
- Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Janice Ortega
- Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Deepak Nijhawan
- Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Guo-Min Li
- Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Weibo Luo
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, USA.,Department of Pharmacology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Yingfei Wang
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, USA. .,Department of Neurology, UT Southwestern Medical Center, Dallas, TX, USA.
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13
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Wu Q, Huang Y, Gu L, Chang Z, Li GM. OTUB1 stabilizes mismatch repair protein MSH2 by blocking ubiquitination. J Biol Chem 2021; 296:100466. [PMID: 33640455 PMCID: PMC8042173 DOI: 10.1016/j.jbc.2021.100466] [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: 10/17/2020] [Revised: 02/19/2021] [Accepted: 02/23/2021] [Indexed: 12/12/2022] Open
Abstract
DNA mismatch repair (MMR) maintains genome stability primarily by correcting replication errors. MMR deficiency can lead to cancer development and bolsters cancer cell resistance to chemotherapy. However, recent studies have shown that checkpoint blockade therapy is effective in MMR-deficient cancers, thus the ability to identify cancer etiology would greatly benefit cancer treatment. MutS homolog 2 (MSH2) is an obligate subunit of mismatch recognition proteins MutSα (MSH2-MSH6) and MutSβ (MSH2-MSH3). Precise regulation of MSH2 is critical, as either over- or underexpression of MSH2 results in an increased mutation frequency. The mechanism by which cells maintain MSH2 proteostasis is unknown. Using functional ubiquitination and deubiquitination assays, we show that the ovarian tumor (OTU) family deubiquitinase ubiquitin aldehyde binding 1 (OTUB1) inhibits MSH2 ubiquitination by blocking the E2 ligase ubiquitin transfer activity. Depleting OTUB1 in cells promotes the ubiquitination and subsequent degradation of MSH2, leading to greater mutation frequency and cellular resistance to genotoxic agents, including the common chemotherapy agents N-methyl-N'-nitro-N-nitrosoguanidine and cisplatin. Taken together, our data identify OTUB1 as an important regulator of MSH2 stability and provide evidence that OTUB1 is a potential biomarker for cancer etiology and therapy.
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Affiliation(s)
- Qiong Wu
- Department of Basic Medical Sciences, Tsinghua University School of Medicine, Beijing, China
| | - Yaping Huang
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Liya Gu
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Zhijie Chang
- Department of Basic Medical Sciences, Tsinghua University School of Medicine, Beijing, China.
| | - Guo-Min Li
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
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14
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Chu JCH, Fong WP, Wong CTT, Ng DKP. Facile Synthesis of Cyclic Peptide-Phthalocyanine Conjugates for Epidermal Growth Factor Receptor-Targeted Photodynamic Therapy. J Med Chem 2021; 64:2064-2076. [PMID: 33577327 DOI: 10.1021/acs.jmedchem.0c01677] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A facile procedure for in situ peptide cyclization and phthalocyanine conjugation was developed by utilizing a bifunctional linker incorporated with a bis(bromomethyl)benzene unit and a cyclopentadiene moiety. These functional groups facilitated the nucleophilic substitution with the two cysteine residues of the linear peptides followed by the Diels-Alder reaction with the maleimide moiety attached to a zinc(II) phthalocyanine. With this approach, three cyclic peptide-phthalocyanine conjugates were prepared in 20-26% isolated yield via a one-pot procedure. One of the conjugates containing a cyclic form of the epidermal growth factor receptor (EGFR)-binding peptide sequence CMYIEALDKYAC displayed superior features as an advanced photosensitizer. It showed preferential uptake by two EGFR-positive cancer cell lines (HT29 and HCT116) compared with two EGFR-negative counterparts (HeLa and HEK293), resulting in significantly higher photocytotoxicity. Intravenous administration of this conjugate into HT29 tumor-bearing nude mice resulted in selective localization in tumor and effective inhibition of tumor growth upon photodynamic treatment.
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Affiliation(s)
- Jacky C H Chu
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
| | - Wing-Ping Fong
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
| | - Clarence T T Wong
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
| | - Dennis K P Ng
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
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15
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Shen M, Young A, Autexier C. PCNA, a focus on replication stress and the alternative lengthening of telomeres pathway. DNA Repair (Amst) 2021; 100:103055. [PMID: 33581499 DOI: 10.1016/j.dnarep.2021.103055] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 01/25/2021] [Indexed: 12/16/2022]
Abstract
The maintenance of telomeres, which are specialized stretches of DNA found at the ends of linear chromosomes, is a crucial step for the immortalization of cancer cells. Approximately 10-15 % of cancer cells use a homologous recombination-based mechanism known as the Alternative Lengthening of Telomeres (ALT) pathway to maintain their telomeres. Telomeres in general pose a challenge to DNA replication owing to their repetitive nature and potential for forming secondary structures. Telomeres in ALT+ cells especially are subject to elevated levels of replication stress compared to telomeres that are maintained by the enzyme telomerase, in part due to the incorporation of telomeric variant repeats at ALT+ telomeres, their on average longer lengths, and their modified chromatin states. Many DNA metabolic strategies exist to counter replication stress and to protect stalled replication forks. The role of proliferating cell nuclear antigen (PCNA) as a platform for recruiting protein partners that participate in several of these DNA replication and repair pathways has been well-documented. We propose that many of these pathways may be active at ALT+ telomeres, either to facilitate DNA replication, to manage replication stress, or during telomere extension. Here, we summarize recent evidence detailing the role of PCNA in pathways including DNA secondary structure resolution, DNA damage bypass, replication fork restart, and DNA damage synthesis. We propose that an examination of PCNA and its post-translational modifications (PTMs) may offer a unique lens by which we might gain insight into the DNA metabolic landscape that is distinctively present at ALT+ telomeres.
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Affiliation(s)
- Michelle Shen
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, H3A 0C7, Canada; Jewish General Hospital, Lady Davis Institute, Montreal, Quebec, H3T 1E2, Canada
| | - Adrian Young
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, H3A 0C7, Canada; Jewish General Hospital, Lady Davis Institute, Montreal, Quebec, H3T 1E2, Canada
| | - Chantal Autexier
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, H3A 0C7, Canada; Jewish General Hospital, Lady Davis Institute, Montreal, Quebec, H3T 1E2, Canada.
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16
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Diagnosis of Lynch Syndrome and Strategies to Distinguish Lynch-Related Tumors from Sporadic MSI/dMMR Tumors. Cancers (Basel) 2021; 13:cancers13030467. [PMID: 33530449 PMCID: PMC7865821 DOI: 10.3390/cancers13030467] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 01/19/2021] [Accepted: 01/22/2021] [Indexed: 02/07/2023] Open
Abstract
Simple Summary Microsatellite instability (MSI) is a hallmark of Lynch syndrome (LS)-related tumors but is not specific, as most of MSI/mismatch repair-deficient (dMMR) tumors are sporadic. Therefore, the identification of MSI/dMMR requires additional diagnostic tools to identify LS. In this review, we address the hallmarks of LS and present recent advances in diagnostic and screening strategies to identify LS patients. We also discuss the pitfalls associated with current strategies, which should be taken into account in order to improve the diagnosis of LS. Abstract Microsatellite instability (MSI) is a hallmark of Lynch syndrome (LS)-related tumors but is not specific to it, as approximately 80% of MSI/mismatch repair-deficient (dMMR) tumors are sporadic. Methods leading to the diagnosis of LS have considerably evolved in recent years and so have tumoral tests for LS screening and for the discrimination of LS-related to MSI-sporadic tumors. In this review, we address the hallmarks of LS, including the clinical, histopathological, and molecular features. We present recent advances in diagnostic and screening strategies to identify LS patients. We also discuss the pitfalls associated with the current strategies, which should be taken into account to improve the diagnosis of LS and avoid inappropriate clinical management.
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17
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HDAC3 deacetylates the DNA mismatch repair factor MutSβ to stimulate triplet repeat expansions. Proc Natl Acad Sci U S A 2020; 117:23597-23605. [PMID: 32900932 PMCID: PMC7519323 DOI: 10.1073/pnas.2013223117] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Trinucleotide repeat (TNR) expansions cause nearly 20 severe human neurological diseases which are currently untreatable. For some of these diseases, ongoing somatic expansions accelerate disease progression and may influence age of onset. This new knowledge emphasizes the importance of understanding the protein factors that drive expansions. Recent genetic evidence indicates that the mismatch repair factor MutSβ (Msh2-Msh3 complex) and the histone deacetylase HDAC3 function in the same pathway to drive triplet repeat expansions. Here we tested the hypothesis that HDAC3 deacetylates MutSβ and thereby activates it to drive expansions. The HDAC3-selective inhibitor RGFP966 was used to examine its biological and biochemical consequences in human tissue culture cells. HDAC3 inhibition efficiently suppresses repeat expansion without impeding canonical mismatch repair activity. Five key lysine residues in Msh3 are direct targets of HDAC3 deacetylation. In cells expressing Msh3 in which these lysine residues are mutated to arginine, the inhibitory effect of RGFP966 on expansions is largely bypassed, consistent with the direct deacetylation hypothesis. RGFP966 treatment does not alter MutSβ subunit abundance or complex formation but does partially control its subcellular localization. Deacetylation sites in Msh3 overlap a nuclear localization signal, and we show that localization of MutSβ is partially dependent on HDAC3 activity. Together, these results indicate that MutSβ is a key target of HDAC3 deacetylation and provide insights into an innovative regulatory mechanism for triplet repeat expansions. The results suggest expansion activity may be druggable and support HDAC3-selective inhibition as an attractive therapy in some triplet repeat expansion diseases.
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18
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Ma X, Tang TS, Guo C. Regulation of translesion DNA synthesis in mammalian cells. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2020; 61:680-692. [PMID: 31983077 DOI: 10.1002/em.22359] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 12/29/2019] [Accepted: 01/21/2020] [Indexed: 06/10/2023]
Abstract
The genomes of all living cells are under endogenous and exogenous attacks every day, causing diverse genomic lesions. Most of the lesions can be timely repaired by multiple DNA repair pathways. However, some may persist during S-phase, block DNA replication, and challenge genome integrity. Eukaryotic cells have evolved DNA damage tolerance (DDT) to mitigate the lethal effects of arrested DNA replication without prior removal of the offending DNA damage. As one important mode of DDT, translesion DNA synthesis (TLS) utilizes multiple low-fidelity DNA polymerases to incorporate nucleotides opposite DNA lesions to maintain genome integrity. Three different mechanisms have been proposed to regulate the polymerase switching between high-fidelity DNA polymerases in the replicative machinery and one or more specialized enzymes. Additionally, it is known that proliferating cell nuclear antigen (PCNA) mono-ubiquitination is essential for optimal TLS. Given its error-prone property, TLS is closely associated with spontaneous and drug-induced mutations in cells, which can potentially lead to tumorigenesis and chemotherapy resistance. Therefore, TLS process must be tightly modulated to avoid unwanted mutagenesis. In this review, we will focus on polymerase switching and PCNA mono-ubiquitination, the two key events in TLS pathway in mammalian cells, and summarize current understandings of regulation of TLS process at the levels of protein-protein interactions, post-translational modifications as well as transcription and noncoding RNAs. Environ. Mol. Mutagen. 61:680-692, 2020. © 2020 Wiley Periodicals, Inc.
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Affiliation(s)
- Xiaolu Ma
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, China
| | - Tie-Shan Tang
- State Key Laboratory of Membrane Biology, Institute of Zoology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, China
| | - Caixia Guo
- CAS Key Laboratory of Genomics and Precision Medicine, Beijing Institute of Genomics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, China
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19
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Chen MK, Hsu JL, Hung MC. Nuclear receptor tyrosine kinase transport and functions in cancer. Adv Cancer Res 2020; 147:59-107. [PMID: 32593407 DOI: 10.1016/bs.acr.2020.04.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Signaling functions of plasma membrane-localized receptor tyrosine kinases (RTKs) have been extensively studied after they were first described in the mid-1980s. Plasma membrane RTKs are activated by extracellular ligands and cellular stress stimuli, and regulate cellular responses by activating the downstream effector proteins to initiate a wide range of signaling cascades in the cells. However, increasing evidence indicates that RTKs can also be transported into the intracellular compartments where they phosphorylate traditional effector proteins and non-canonical substrate proteins. In general, internalization that retains the RTK's transmembrane domain begins with endocytosis, and endosomal RTK remains active before being recycled or degraded. Further RTK retrograde transport from endosome-Golgi-ER to the nucleus is primarily dependent on membranes vesicles and relies on the interaction with the COP-I vesicle complex, Sec61 translocon complex, and importin. Internalized RTKs have non-canonical substrates that include transcriptional co-factors and DNA damage response proteins, and many nuclear RTKs harbor oncogenic properties and can enhance cancer progression. Indeed, nuclear-localized RTKs have been shown to positively correlate with cancer recurrence, therapeutic resistance, and poor prognosis of cancer patients. Therefore, understanding the functions of nuclear RTKs and the mechanisms of nuclear RTK transport will further improve our knowledge to evaluate the potential of targeting nuclear RTKs or the proteins involved in their transport as new cancer therapeutic strategies.
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Affiliation(s)
- Mei-Kuang Chen
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States; The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, United States
| | - Jennifer L Hsu
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, United States
| | - Mien-Chie Hung
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States; Graduate Institute of Biomedical Sciences, Research Center for Cancer Biology, and Center for Molecular Medicine, China Medical University, Taichung, Taiwan.
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20
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González-Magaña A, Blanco FJ. Human PCNA Structure, Function and Interactions. Biomolecules 2020; 10:biom10040570. [PMID: 32276417 PMCID: PMC7225939 DOI: 10.3390/biom10040570] [Citation(s) in RCA: 132] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 04/01/2020] [Accepted: 04/03/2020] [Indexed: 12/13/2022] Open
Abstract
Proliferating cell nuclear antigen (PCNA) is an essential factor in DNA replication and repair. It forms a homotrimeric ring that embraces the DNA and slides along it, anchoring DNA polymerases and other DNA editing enzymes. It also interacts with regulatory proteins through a sequence motif known as PCNA Interacting Protein box (PIP-box). We here review the latest contributions to knowledge regarding the structure-function relationships in human PCNA, particularly the mechanism of sliding, and of the molecular recognition of canonical and non-canonical PIP motifs. The unique binding mode of the oncogene p15 is described in detail, and the implications of the recently discovered structure of PCNA bound to polymerase δ are discussed. The study of the post-translational modifications of PCNA and its partners may yield therapeutic opportunities in cancer treatment, in addition to illuminating the way PCNA coordinates the dynamic exchange of its many partners in DNA replication and repair.
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Affiliation(s)
- Amaia González-Magaña
- CIC bioGUNE, Bizkaia Science and Technology Park, bld 800, 48160 Derio, Bizkaia, Spain;
| | - Francisco J. Blanco
- CIC bioGUNE, Bizkaia Science and Technology Park, bld 800, 48160 Derio, Bizkaia, Spain;
- IKERBASQUE, Basque Foundation for Science, Maria Diaz de Haro 3, 6 solairua, 48013 Bilbao, Bizkaia, Spain
- Correspondence:
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21
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Modulation of proliferation factors in lung adenocarcinoma with an analysis of the transcriptional consequences of genomic EGFR activation. Oncotarget 2019; 10:6913-6933. [PMID: 31857847 PMCID: PMC6916753 DOI: 10.18632/oncotarget.27316] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Accepted: 10/26/2019] [Indexed: 11/25/2022] Open
Abstract
Genes of the pre-replication, pre-initiation and replisome complexes duplicate the genome from many sites once in a normal cell cycle. This study examines complex components in lung adenocarcinoma (LUAD) closely, correlating changes in the genome and transcriptome with proliferation and overall survival. Molecular subtypes (The Cancer Genome Atlas (TCGA), 2014) based on copy number, DNA methylation, and mRNA expression had variable proliferation levels, the highest correlating with decreased survival. A pattern of increased expression typified by POLE2 and POLQ was found for multiple replication factors over thirty-seven tumor types. EGFR altered cases unanticipatedly inversely correlated with proliferation factor expression in LUAD, Colon adenocarcinoma, and Cancer Cell Line Encyclopedia cell lines, but not in glioblastoma or breast cancer. Activation mutations did not uniformly correlate with proliferation, most cases were pre-metastatic. A gene expression profile was identified, and pathway involvement considered. Significantly, results suggest EGFR over expression and activation are early alterations that likely stall the replication complex through PCNA phosphorylation creating replication stress responsible for DNA damage response and further mutation, but does not promote increased proliferation itself. An argument is presented that the mechanism driving lethality in this tumor cohort could differ from over proliferation seen in other LUAD.
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22
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Buehler J, Carpenter E, Zeltzer S, Igarashi S, Rak M, Mikell I, Nelson JA, Goodrum F. Host signaling and EGR1 transcriptional control of human cytomegalovirus replication and latency. PLoS Pathog 2019; 15:e1008037. [PMID: 31725811 PMCID: PMC6855412 DOI: 10.1371/journal.ppat.1008037] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Accepted: 08/21/2019] [Indexed: 12/15/2022] Open
Abstract
Sustained phosphotinositide3-kinase (PI3K) signaling is critical to the maintenance of alpha and beta herpesvirus latency. We have previously shown that the beta-herpesvirus, human cytomegalovirus (CMV), regulates epidermal growth factor receptor (EGFR), upstream of PI3K, to control states of latency and reactivation. How signaling downstream of EGFR is regulated and how this impacts CMV infection and latency is not fully understood. We demonstrate that CMV downregulates EGFR early in the productive infection, which blunts the activation of EGFR and its downstream pathways in response to stimuli. However, CMV infection sustains basal levels of EGFR and downstream pathway activity in the context of latency in CD34+ hematopoietic progenitor cells (HPCs). Inhibition of MEK/ERK, STAT or PI3K/AKT pathways downstream of EGFR increases viral reactivation from latently infected CD34+ HPCs, defining a role for these pathways in latency. We hypothesized that CMV modulation of EGFR signaling might impact viral transcription important to latency. Indeed, EGF-stimulation increased expression of the UL138 latency gene, but not immediate early or early viral genes, suggesting that EGFR signaling promotes latent gene expression. The early growth response-1 (EGR1) transcription factor is induced downstream of EGFR signaling through the MEK/ERK pathway and is important for the maintenance of hematopoietic stemness. We demonstrate that EGR1 binds the viral genome upstream of UL138 and is sufficient to promote UL138 expression. Further, disruption of EGR1 binding upstream of UL138 prevents the establishment of latency in CD34+ HPCs. Our results indicate a model whereby UL138 modulation of EGFR signaling feeds back to promote UL138 gene expression and suppression of replication for latency. By this mechanism, the virus has hardwired itself into host cell biology to sense and respond to changes in homeostatic host cell signaling. Host signaling is important for regulating states of cytomegalovirus (CMV) replication and latency. We have shown that human cytomegalovirus regulates EGFR levels and trafficking and that sustained EGFR or downstream PI3K signaling is a requirement for viral latency. Changes in host signaling have the ability to alter viral and host gene expression to impact the outcome of infection. Here we show that EGFR signaling through MEK/ERK pathway induces the host EGR1 transcription factor that is highly expressed in hematopoietic stem cells and necessary for the maintenance of hematopoietic stemness. Downregulation of EGR1 promotes stem cell mobilization and differentiation, known stimuli for CMV reactivation. We identified functional EGR1 binding sites upstream of the UL138 CMV latency gene and EGR1 stimulated UL138 expression to reinforce the latent infection. Mutant viruses where the regulation of UL138 by EGR1 is disrupted are unable to establish latency in CD34+ HPCs. This study advances our understanding of how host signaling impacts decisions to enter into or exit from latency. The regulation of viral gene expression by host signaling allows the virus to sense and respond to changes in host stress or differentiation.
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Affiliation(s)
- Jason Buehler
- BIO5 Institute, University of Arizona, Tucson, Arizona, United States of America
| | - Ethan Carpenter
- BIO5 Institute, University of Arizona, Tucson, Arizona, United States of America
| | - Sebastian Zeltzer
- BIO5 Institute, University of Arizona, Tucson, Arizona, United States of America
| | - Suzu Igarashi
- BIO5 Institute, University of Arizona, Tucson, Arizona, United States of America
| | - Michael Rak
- BIO5 Institute, University of Arizona, Tucson, Arizona, United States of America
| | - Iliyana Mikell
- Vaccine and Gene Therapy Institute, Oregon Health & Science University, Beaverton, Oregon, United States of America
| | - Jay A. Nelson
- Vaccine and Gene Therapy Institute, Oregon Health & Science University, Beaverton, Oregon, United States of America
| | - Felicia Goodrum
- BIO5 Institute, University of Arizona, Tucson, Arizona, United States of America
- Department of Immunobiology, University of Arizona, Tucson, Arizona, United States of America
- * E-mail:
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23
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Yang D, Yao X, Zhou J, Zhou H, Lu G, Wang Y. Correlations of PCNA expression with thyroid cancer ultrasound and histopathologic features. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2019; 12:1378-1384. [PMID: 31933952 PMCID: PMC6947062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 01/16/2019] [Indexed: 06/10/2023]
Abstract
OBJECTIVE To investigate the correlations of proliferating cell nuclear antigen (PCNA) gene expression with thyroid cancer (TC) ultrasound (US) features, histopathology and clinical stage. METHODS A total of 66 TC patients admitted and treated in the Department of Oncology of our hospital from April 2014 to April 2018 were enrolled randomly. The conventional US imaging data of the patients were collected. Paired carcinoma and para-carcinoma tissues were obtained after operation to detect the expression of PCNA protein by immunohistochemistry (IHC). The correlations of PCNA expression with the patients' US manifestations and clinical stages were analyzed. RESULTS The positive rate of PCNA was 72.73% (48/66) in TC tissues and 13.64% (9/66) in paired para-carcinoma tissues, displaying a statistically significant difference between the two groups (P<0.05). The PCNA and US features suggested that there was no significant difference in tumor boundary between the PCNA positive group and PCNA negative group (P>0.05). However, significant differences in tumor diameter, echo, calcification and blood flow were found between the two groups (P<0.05). The pathologic data of preoperative US diagnosis and PCNA expression in postoperative TC specimens were analyzed, and the results indicated that PCNA expression was prominently associated with T stage and N stage in US diagnosis (P<0.05). The total correct rate of US in assessing the T stage was 75.8% (50/66), and the over-staging rate and under-staging rate in evaluating the T stage were 13.6% (9/66) and 10.6% (7/66), respectively. CONCLUSION The expression of PCNA protein in TC tissues is significantly correlated with the diameter, echo, calcification and blood flow of US features as well as clinical stage detected by US. PCNA level and US examination can provide certain clinical values for TC treatment.
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Affiliation(s)
- Debin Yang
- Department of Ultrasound, Jiading District Central Hospital Affiliated Shanghai University of Medicine and Health SciencesShanghai, China
| | - Xiaohua Yao
- Department of Ultrasound, Jiading District Central Hospital Affiliated Shanghai University of Medicine and Health SciencesShanghai, China
| | - Jie Zhou
- Department of Ultrasound, Jiading District Central Hospital Affiliated Shanghai University of Medicine and Health SciencesShanghai, China
| | - Haihua Zhou
- Department of General Surger, Jiading District Central Hospital Affiliated Shanghai University of Medicine and Health SciencesShanghai, China
| | - Guofeng Lu
- Department of Pathology, Jiading District Central Hospital Affiliated Shanghai University of Medicine and Health SciencesShanghai, China
| | - Yingchun Wang
- Department of Ultrasound, Jiading District Central Hospital Affiliated Shanghai University of Medicine and Health SciencesShanghai, China
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Peng B, Ortega J, Gu L, Chang Z, Li GM. Phosphorylation of proliferating cell nuclear antigen promotes cancer progression by activating the ATM/Akt/GSK3β/Snail signaling pathway. J Biol Chem 2019; 294:7037-7045. [PMID: 30858175 DOI: 10.1074/jbc.ra119.007897] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 03/03/2019] [Indexed: 12/19/2022] Open
Abstract
Proliferating cell nuclear antigen (PCNA) and its posttranslational modifications regulate DNA metabolic reactions, including DNA replication and repair, at replication forks. PCNA phosphorylation at Tyr-211 (PCNA-Y211p) inhibits DNA mismatch repair and induces misincorporation during DNA synthesis. Here, we describe an unexpected role of PCNA-Y211p in cancer promotion and development. Cells expressing phosphorylation-mimicking PCNA, PCNA-Y211D, show elevated hallmarks specific to the epithelial-mesenchymal transition (EMT), including the up-regulation of the EMT-promoting factor Snail and the down-regulation of EMT-inhibitory factors E-cadherin and GSK3β. The PCNA-Y211D-expressing cells also exhibited active cell migration and underwent G2/M arrest. Interestingly, all of these EMT-associated activities required the activation of ATM and Akt kinases, as inactivating these protein kinases by gene knockdown or inhibitors blocked EMT-associated signaling and cell migration. We concluded that PCNA phosphorylation promotes cancer progression via the ATM/Akt/GSK3β/Snail signaling pathway. In conclusion, this study identifies a novel PCNA function and reveals the molecular basis of phosphorylated PCNA-mediated cancer development and progression.
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Affiliation(s)
- Bo Peng
- From the Department of Basic Medical Sciences, Tsinghua University School of Medicine, Beijing, China 100084 and
| | - Janice Ortega
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Liya Gu
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Zhijie Chang
- From the Department of Basic Medical Sciences, Tsinghua University School of Medicine, Beijing, China 100084 and
| | - Guo-Min Li
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas 75390
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25
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Guimaraes-Young A, Feddersen CR, Dupuy AJ. Sleeping Beauty Mouse Models of Cancer: Microenvironmental Influences on Cancer Genetics. Front Oncol 2019; 9:611. [PMID: 31338332 PMCID: PMC6629774 DOI: 10.3389/fonc.2019.00611] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 06/21/2019] [Indexed: 12/13/2022] Open
Abstract
The Sleeping Beauty (SB) transposon insertional mutagenesis system offers a streamlined approach to identify genetic drivers of cancer. With a relatively random insertion profile, SB is uniquely positioned for conducting unbiased forward genetic screens. Indeed, SB mouse models of cancer have revealed insights into the genetics of tumorigenesis. In this review, we highlight experiments that have exploited the SB system to interrogate the genetics of cancer in distinct biological contexts. We also propose experimental designs that could further our understanding of the relationship between tumor microenvironment and tumor progression.
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Affiliation(s)
- Amy Guimaraes-Young
- Department of Anatomy and Cell Biology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Charlotte R Feddersen
- Department of Anatomy and Cell Biology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Adam J Dupuy
- Department of Anatomy and Cell Biology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, United States
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26
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Leung W, Baxley RM, Moldovan GL, Bielinsky AK. Mechanisms of DNA Damage Tolerance: Post-Translational Regulation of PCNA. Genes (Basel) 2018; 10:genes10010010. [PMID: 30586904 PMCID: PMC6356670 DOI: 10.3390/genes10010010] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 12/18/2018] [Accepted: 12/19/2018] [Indexed: 12/12/2022] Open
Abstract
DNA damage is a constant source of stress challenging genomic integrity. To ensure faithful duplication of our genomes, mechanisms have evolved to deal with damage encountered during replication. One such mechanism is referred to as DNA damage tolerance (DDT). DDT allows for replication to continue in the presence of a DNA lesion by promoting damage bypass. Two major DDT pathways exist: error-prone translesion synthesis (TLS) and error-free template switching (TS). TLS recruits low-fidelity DNA polymerases to directly replicate across the damaged template, whereas TS uses the nascent sister chromatid as a template for bypass. Both pathways must be tightly controlled to prevent the accumulation of mutations that can occur from the dysregulation of DDT proteins. A key regulator of error-prone versus error-free DDT is the replication clamp, proliferating cell nuclear antigen (PCNA). Post-translational modifications (PTMs) of PCNA, mainly by ubiquitin and SUMO (small ubiquitin-like modifier), play a critical role in DDT. In this review, we will discuss the different types of PTMs of PCNA and how they regulate DDT in response to replication stress. We will also cover the roles of PCNA PTMs in lagging strand synthesis, meiotic recombination, as well as somatic hypermutation and class switch recombination.
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Affiliation(s)
- Wendy Leung
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Ryan M Baxley
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA.
| | - George-Lucian Moldovan
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA.
| | - Anja-Katrin Bielinsky
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA.
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27
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Med19 is targeted by miR-101-3p/miR-422a and promotes breast cancer progression by regulating the EGFR/MEK/ERK signaling pathway. Cancer Lett 2018; 444:105-115. [PMID: 30583076 DOI: 10.1016/j.canlet.2018.12.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 12/04/2018] [Accepted: 12/14/2018] [Indexed: 12/23/2022]
Abstract
Our previous study found that mediator complex subunit 19 (Med19) is upregulated and involved in breast cancer tumorigenesis; however, the detailed effects and mechanism of Med19 in breast cancer require further study. In this study, we found that Med19 was obviously elevated in human breast cancer tissues, which was significantly associated with larger tumors, high-grade malignant features and poor prognosis. Furthermore, Med19 enhanced breast cancer cell proliferation, epithelial-mesenchymal transition, invasion and migration in vitro and in vivo. Med19 interacted with epidermal growth factor receptor (EGFR) and increased EGFR expression. Moreover, Med19 activated the EGFR/mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway and exerted its oncogenic activity in an EGFR signaling-mediated manner. In addition, Med19 expression was regulated by miR-101-3p and miR-422a. Med19 expression positively correlated with EGFR expression and negatively correlated with miR-101-3p and miR-422a expression in human breast cancer tissues. Med19 mediated the crosstalk between miR-101-3p/miR-422a and the EGFR/MEK/ERK signaling pathway. This study revealed a new miR-101-3p/miR-422a-Med19-EGFR/MEK/ERK axis that plays a significant role in breast cancer progression. These results help elucidate the potential mechanisms of Med19 in human breast cancer progression.
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28
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Weßbecher IM, Brieger A. Phosphorylation meets DNA mismatch repair. DNA Repair (Amst) 2018; 72:107-114. [PMID: 30249411 DOI: 10.1016/j.dnarep.2018.09.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 09/04/2018] [Indexed: 12/14/2022]
Abstract
DNA mismatch repair (MMR) is a highly conserved process and ensures the removal of mispaired DNA bases and insertion-deletion loops right after replication. For this, a MutSα or MutSβ protein complex recognizes the DNA damage, MutLα nicks the erroneous strand, exonuclease 1 removes the wrong nucleotides, DNA polymerase δ refills the gap and DNA ligase I joins the fragments to seal the nicks and complete the repair process. The failure to accomplish these functions is associated with higher mutation rates and may lead to cancer, which highlights the importance of MMR by the maintenance of genomic stability. The post-replicative MMR implies that involved proteins are regulated at several levels, including posttranslational modifications (PTMs). Phosphorylation is one of the most common and major PTMs. Suitable with its regulatory force phosphorylation was shown to influence MMR factors thereby adjusting eukaryotic MMR activity. In this review, we summarized the current knowledge of the role of phosphorylation of MMR process involved proteins and their functional relevance.
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Affiliation(s)
| | - Angela Brieger
- Medical Clinic I, Biomedical Research Laboratory, Goethe-University, Frankfurt a.M., Germany.
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29
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Banu K, Mitra P, Subbarao N, Dhar SK. Role of tyrosine residue (Y213) in nuclear retention of PCNA1 in human malaria parasite Plasmodium falciparum. FEMS Microbiol Lett 2018; 365:5056156. [PMID: 30052905 DOI: 10.1093/femsle/fny182] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2018] [Accepted: 07/17/2018] [Indexed: 01/03/2023] Open
Abstract
Proliferating Cell Nuclear Antigen (PCNA) undergoes several post-translational modifications including phosphorylation leading to its regulation in mammalian and yeast systems. Plasmodium falciparum possesses two PCNAs (PCNA1 & PCNA2) with an edge of PfPCNA1 over PfPCNA2 for DNA replication. Recent phospho-proteome data report phosphorylation of S191 residue without its functional implication. In mammalian cells, phosphorylation of HsPCNA at Y211 stabilizes chromatin bound PCNA. We find tyrosine (but not S191) to be conserved in PfPCNAs and it is important for its nuclear localization and foci formation of PfPCNA1. Further, a Y213F mutation in PfPCNA1 leads to its functional loss both in yeast and parasite. We highlight the importance of evolutionarily conserved tyrosine in PCNA from parasite to mammal linked with DNA replication and cell proliferation.
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Affiliation(s)
- Khadija Banu
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Pallabi Mitra
- School of Life Sciences, University of Hyderabad, Hyderabad, 500046, India
| | - Naidu Subbarao
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Suman Kumar Dhar
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India
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30
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Collins-McMillen D, Buehler J, Peppenelli M, Goodrum F. Molecular Determinants and the Regulation of Human Cytomegalovirus Latency and Reactivation. Viruses 2018; 10:E444. [PMID: 30127257 PMCID: PMC6116278 DOI: 10.3390/v10080444] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 08/16/2018] [Accepted: 08/17/2018] [Indexed: 02/06/2023] Open
Abstract
Human cytomegalovirus (HCMV) is a beta herpesvirus that establishes a life-long persistence in the host, like all herpesviruses, by way of a latent infection. During latency, viral genomes are maintained in a quieted state. Virus replication can be reactivated from latency in response to changes in cellular signaling caused by stress or differentiation. The past decade has brought great insights into the molecular basis of HCMV latency. Here, we review the complex persistence of HCMV with consideration of latent reservoirs, viral determinants and their host interactions, and host signaling and the control of cellular and viral gene expression that contributes to the establishment of and reactivation from latency.
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Affiliation(s)
| | - Jason Buehler
- BIO5 Institute, University of Arizona, Tucson, AZ 85721, USA.
| | | | - Felicia Goodrum
- BIO5 Institute, University of Arizona, Tucson, AZ 85721, USA.
- Department of Immunobiology, University of Arizona, Tucson, AZ 85721, USA.
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31
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Maneuvers on PCNA Rings during DNA Replication and Repair. Genes (Basel) 2018; 9:genes9080416. [PMID: 30126151 PMCID: PMC6116012 DOI: 10.3390/genes9080416] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 08/08/2018] [Accepted: 08/09/2018] [Indexed: 12/20/2022] Open
Abstract
DNA replication and repair are essential cellular processes that ensure genome duplication and safeguard the genome from deleterious mutations. Both processes utilize an abundance of enzymatic functions that need to be tightly regulated to ensure dynamic exchange of DNA replication and repair factors. Proliferating cell nuclear antigen (PCNA) is the major coordinator of faithful and processive replication and DNA repair at replication forks. Post-translational modifications of PCNA, ubiquitination and acetylation in particular, regulate the dynamics of PCNA-protein interactions. Proliferating cell nuclear antigen (PCNA) monoubiquitination elicits ‘polymerase switching’, whereby stalled replicative polymerase is replaced with a specialized polymerase, while PCNA acetylation may reduce the processivity of replicative polymerases to promote homologous recombination-dependent repair. While regulatory functions of PCNA ubiquitination and acetylation have been well established, the regulation of PCNA-binding proteins remains underexplored. Considering the vast number of PCNA-binding proteins, many of which have similar PCNA binding affinities, the question arises as to the regulation of the strength and sequence of their binding to PCNA. Here I provide an overview of post-translational modifications on both PCNA and PCNA-interacting proteins and discuss their relevance for the regulation of the dynamic processes of DNA replication and repair.
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32
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Bhattacharya P, Shetake NG, Pandey BN, Kumar A. Receptor tyrosine kinase signaling in cancer radiotherapy and its targeting for tumor radiosensitization. Int J Radiat Biol 2018; 94:628-644. [DOI: 10.1080/09553002.2018.1478160] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Poushali Bhattacharya
- Radiation Signaling and Cancer Biology Section, Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai, India
| | - Neena G. Shetake
- Radiation Signaling and Cancer Biology Section, Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai, India
| | - Badri N. Pandey
- Radiation Signaling and Cancer Biology Section, Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai, India
| | - Amit Kumar
- Radiation Signaling and Cancer Biology Section, Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai, India
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33
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Molecular genetics and cellular events of K-Ras-driven tumorigenesis. Oncogene 2017; 37:839-846. [PMID: 29059163 PMCID: PMC5817384 DOI: 10.1038/onc.2017.377] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 08/11/2017] [Accepted: 09/08/2017] [Indexed: 02/06/2023]
Abstract
Cellular transformation and the accumulation of genomic instability are the two key events required for tumorigenesis. K-Ras (Kirsten-rat sarcoma viral oncogene homolog) is a prominent oncogene that has been proven to drive tumorigenesis. K-Ras also modulates numerous genetic regulatory mechanisms and forms a large tumorigenesis network. In this review, we track the genetic aspects of K-Ras signaling networks and assemble the sequence of cellular events that constitute the tumorigenesis process, such as regulation of K-Ras expression (which is influenced by miRNA, small nucleolar RNA and lncRNA), activation of K-Ras (mutations), generation of reactive oxygen species (ROS), induction of DNA damage and apoptosis, induction of DNA damage repair pathways and ROS detoxification systems, cellular transformation after apoptosis by the blebbishield emergency program and the accumulation of genomic/chromosomal instability that leads to tumorigenesis.
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34
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Waraky A, Lin Y, Warsito D, Haglund F, Aleem E, Larsson O. Nuclear insulin-like growth factor 1 receptor phosphorylates proliferating cell nuclear antigen and rescues stalled replication forks after DNA damage. J Biol Chem 2017; 292:18227-18239. [PMID: 28924044 DOI: 10.1074/jbc.m117.781492] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 09/15/2017] [Indexed: 12/20/2022] Open
Abstract
We have previously shown that the insulin-like growth factor 1 receptor (IGF-1R) translocates to the cell nucleus, where it binds to enhancer-like regions and increases gene transcription. Further studies have demonstrated that nuclear IGF-1R (nIGF-1R) physically and functionally interacts with some nuclear proteins, i.e. the lymphoid enhancer-binding factor 1 (Lef1), histone H3, and Brahma-related gene-1 proteins. In this study, we identified the proliferating cell nuclear antigen (PCNA) as a nIGF-1R-binding partner. PCNA is a pivotal component of the replication fork machinery and a main regulator of the DNA damage tolerance (DDT) pathway. We found that IGF-1R interacts with and phosphorylates PCNA in human embryonic stem cells and other cell lines. In vitro MS analysis of PCNA co-incubated with the IGF-1R kinase indicated tyrosine residues 60, 133, and 250 in PCNA as IGF-1R targets, and PCNA phosphorylation was followed by mono- and polyubiquitination. Co-immunoprecipitation experiments suggested that these ubiquitination events may be mediated by DDT-dependent E2/E3 ligases (e.g. RAD18 and SHPRH/HLTF). Absence of IGF-1R or mutation of Tyr-60, Tyr-133, or Tyr-250 in PCNA abrogated its ubiquitination. Unlike in cells expressing IGF-1R, externally induced DNA damage in IGF-1R-negative cells caused G1 cell cycle arrest and S phase fork stalling. Taken together, our results suggest a role of IGF-1R in DDT.
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Affiliation(s)
- Ahmed Waraky
- From the Department of Oncology-Pathology, Cancer Center Karolinska, Karolinska Institutet, Stockholm SE-171 76, Sweden
| | - Yingbo Lin
- From the Department of Oncology-Pathology, Cancer Center Karolinska, Karolinska Institutet, Stockholm SE-171 76, Sweden
| | - Dudi Warsito
- From the Department of Oncology-Pathology, Cancer Center Karolinska, Karolinska Institutet, Stockholm SE-171 76, Sweden
| | - Felix Haglund
- From the Department of Oncology-Pathology, Cancer Center Karolinska, Karolinska Institutet, Stockholm SE-171 76, Sweden
| | - Eiman Aleem
- From the Department of Oncology-Pathology, Cancer Center Karolinska, Karolinska Institutet, Stockholm SE-171 76, Sweden
| | - Olle Larsson
- From the Department of Oncology-Pathology, Cancer Center Karolinska, Karolinska Institutet, Stockholm SE-171 76, Sweden
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35
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Bartolowits MD, Brown W, Ali R, Pedley AM, Chen Q, Harvey KE, Wendt MK, Davisson VJ. Selective Inhibition of STAT3 Phosphorylation Using a Nuclear-Targeted Kinase Inhibitor. ACS Chem Biol 2017; 12:2371-2378. [PMID: 28787571 DOI: 10.1021/acschembio.7b00341] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The discovery of compounds that selectively modulate signaling and effector proteins downstream of EGFR could have important implications for understanding specific roles for pathway activation. A complicating factor for receptor tyrosine kinases is their capacity to be translocated to the nucleus upon ligand engagement. Once localized in subcellular compartments like the nucleus, the roles for EGFR take on additional features, many of which are still being revealed. Additionally, nuclear localization of EGFR has been implicated in downstream events that have significance for therapy resistance and disease progression. The challenges to addressing the differential roles for EGFR in the nucleus motivated experimental approaches that can selectively modulate its subcellular function. By adding modifications to the established EGFR kinase inhibitor gefitinib, an approach to small molecule conjugates with a unique nuclear-targeting peptoid sequence was tested in both human and murine breast tumor cell models for their capacity to inhibit EGF-stimulated activation of ERK1/2 and STAT3. While gefitinib alone inhibits both of these downstream effectors, data acquired here indicate that compartmentalization of the gefitinib conjugates allows for pathway specific inhibition of STAT3 while not affecting ERK1/2 signaling. The inhibitor conjugates offered a more direct route to evaluate the role of EGF-stimulated epithelial-to-mesenchymal transition in these breast cancer cell models. These conjugates revealed that STAT3 activation is not involved in EGF-induced EMT, and instead utilization of the cytoplasmic MAP kinase signaling pathway is critical to this process. This is the first example of a conjugate kinase inhibitor capable of partitioning to the nucleus and offers a new approach to enhancing kinase inhibitor specificity.
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Affiliation(s)
- Matthew D. Bartolowits
- Department of Medicinal Chemistry
and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana 47907, United States
| | - Wells Brown
- Department of Medicinal Chemistry
and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana 47907, United States
| | - Remah Ali
- Department of Medicinal Chemistry
and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana 47907, United States
| | - Anthony M. Pedley
- Department of Medicinal Chemistry
and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana 47907, United States
| | - Qingshou Chen
- Department of Medicinal Chemistry
and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana 47907, United States
| | - Kyle E. Harvey
- Department of Medicinal Chemistry
and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana 47907, United States
| | - Michael K. Wendt
- Department of Medicinal Chemistry
and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana 47907, United States
| | - Vincent Jo Davisson
- Department of Medicinal Chemistry
and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana 47907, United States
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Choe KN, Moldovan GL. Forging Ahead through Darkness: PCNA, Still the Principal Conductor at the Replication Fork. Mol Cell 2017; 65:380-392. [PMID: 28157503 DOI: 10.1016/j.molcel.2016.12.020] [Citation(s) in RCA: 203] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 11/28/2016] [Accepted: 12/21/2016] [Indexed: 10/20/2022]
Abstract
Proliferating cell nuclear antigen (PCNA) lies at the center of the faithful duplication of eukaryotic genomes. With its distinctive doughnut-shaped molecular structure, PCNA was originally studied for its role in stimulating DNA polymerases. However, we now know that PCNA does much more than promote processive DNA synthesis. Because of the complexity of the events involved, cellular DNA replication poses major threats to genomic integrity. Whatever predicament lies ahead for the replication fork, PCNA is there to orchestrate the events necessary to handle it. Through its many protein interactions and various post-translational modifications, PCNA has far-reaching impacts on a myriad of cellular functions.
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Affiliation(s)
- Katherine N Choe
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - George-Lucian Moldovan
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA.
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DNA mismatch repair and its many roles in eukaryotic cells. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2017; 773:174-187. [PMID: 28927527 DOI: 10.1016/j.mrrev.2017.07.001] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 07/01/2017] [Accepted: 07/06/2017] [Indexed: 02/06/2023]
Abstract
DNA mismatch repair (MMR) is an important DNA repair pathway that plays critical roles in DNA replication fidelity, mutation avoidance and genome stability, all of which contribute significantly to the viability of cells and organisms. MMR is widely-used as a diagnostic biomarker for human cancers in the clinic, and as a biomarker of cancer susceptibility in animal model systems. Prokaryotic MMR is well-characterized at the molecular and mechanistic level; however, MMR is considerably more complex in eukaryotic cells than in prokaryotic cells, and in recent years, it has become evident that MMR plays novel roles in eukaryotic cells, several of which are not yet well-defined or understood. Many MMR-deficient human cancer cells lack mutations in known human MMR genes, which strongly suggests that essential eukaryotic MMR components/cofactors remain unidentified and uncharacterized. Furthermore, the mechanism by which the eukaryotic MMR machinery discriminates between the parental (template) and the daughter (nascent) DNA strand is incompletely understood and how cells choose between the EXO1-dependent and the EXO1-independent subpathways of MMR is not known. This review summarizes recent literature on eukaryotic MMR, with emphasis on the diverse cellular roles of eukaryotic MMR proteins, the mechanism of strand discrimination and cross-talk/interactions between and co-regulation of MMR and other DNA repair pathways in eukaryotic cells. The main conclusion of the review is that MMR proteins contribute to genome stability through their ability to recognize and promote an appropriate cellular response to aberrant DNA structures, especially when they arise during DNA replication. Although the molecular mechanism of MMR in the eukaryotic cell is still not completely understood, increased used of single-molecule analyses in the future may yield new insight into these unsolved questions.
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Kanao R, Masutani C. Regulation of DNA damage tolerance in mammalian cells by post-translational modifications of PCNA. Mutat Res 2017; 803-805:82-88. [PMID: 28666590 DOI: 10.1016/j.mrfmmm.2017.06.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 05/25/2017] [Accepted: 06/19/2017] [Indexed: 11/29/2022]
Abstract
DNA damage tolerance pathways, which include translesion DNA synthesis (TLS) and template switching, are crucial for prevention of DNA replication arrest and maintenance of genomic stability. However, these pathways utilize error-prone DNA polymerases or template exchange between sister DNA strands, and consequently have the potential to induce mutations or chromosomal rearrangements. Post-translational modifications of proliferating cell nuclear antigen (PCNA) play important roles in controlling these pathways. For example, TLS is mediated by mono-ubiquitination of PCNA at lysine 164, for which RAD6-RAD18 is the primary E2-E3 complex. Elaborate protein-protein interactions between mono-ubiquitinated PCNA and Y-family DNA polymerases constitute the core of the TLS regulatory system, and enhancers of PCNA mono-ubiquitination and de-ubiquitinating enzymes finely regulate TLS and suppress TLS-mediated mutagenesis. The template switching pathway is promoted by K63-linked poly-ubiquitination of PCNA at lysine 164. Poly-ubiquitination is achieved by a coupled reaction mediated by two sets of E2-E3 complexes, RAD6-RAD18 and MMS2-UBC13-HTLF/SHPRH. In addition to these mono- and poly-ubiquitinations, simultaneous mono-ubiquitinations on multiple units of the PCNA homotrimeric ring promote an unidentified damage tolerance mechanism that remains to be fully characterized. Furthermore, SUMOylation of PCNA in mammalian cells can negatively regulate recombination. Other modifications, including ISGylation, acetylation, methylation, or phosphorylation, may also play roles in DNA damage tolerance and control of genomic stability.
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Affiliation(s)
- Rie Kanao
- Department of Genome Dynamics, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | - Chikahide Masutani
- Department of Genome Dynamics, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.
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39
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Affiliation(s)
- Guo-Min Li
- Department of Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, University of Southern California, Los Angeles, CA 90033.
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40
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Valenciano AL, Knudsen GM, Mackey ZB. Extracellular-signal regulated kinase 8 of Trypanosoma brucei uniquely phosphorylates its proliferating cell nuclear antigen homolog and reveals exploitable properties. Cell Cycle 2016; 15:2827-41. [PMID: 27589575 PMCID: PMC5053586 DOI: 10.1080/15384101.2016.1222340] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The Trypanosoma brucei subspecies T. brucei gambiense and T. brucei rhodesiense are vector-borne pathogens that cause sleeping sickness also known as Human African Trypanosomiasis (HAT), which is fatal if left untreated. The drugs that treat HAT are ineffective and cause toxic side effects. One strategy for identifying safer and more effective HAT drugs is to therapeutically exploit essential gene targets in T. brucei. Genes that make up a basic mitogen-activated protein kinase (MAPK) network are present in T. brucei. Tb927.10.5140 encodes an essential MAPK that is homologous to the human extracellular-signal regulated kinase 8 (HsERK8) which forms a tight complex with the replication factor proliferating cell nuclear antigen (PCNA) to stabilize intracellular PCNA levels. Here we demonstrate that (TbPCNA) is uniquely phos-phorylated on serine (S) and threonine (T) residues in T. brucei and that TbERK8 phosphorylates TbPCNA at each of these residues. The ability of an ERK8 homolog to phosphorylate a PCNA homolog is a novel biochemical property that is first demonstrated here in T. brucei and may be unique to this pathogen. We demonstrate that the potent HsERK8 inhibitor Ro318220, has an IC50 for TbERK8 that is several hundred times higher than its reported IC50 for HsERK8. This indicated that the active sites of TbERK8 and HsERK8 can be selectively inhibited, which provides a rational basis for discovering inhibitors that specifically target this essential parasite MAPK to kill the parasite.
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Affiliation(s)
- Ana L Valenciano
- a Department of Biochemistry and Fralin Life Science Institute , Vector-Borne Disease Division, Virginia Polytechnic Institute and State University , Blacksburg , VA , USA
| | - Giselle M Knudsen
- b Department of Pharmaceutical Chemistry , University of California San Francisco , San Francisco , CA , USA
| | - Zachary B Mackey
- a Department of Biochemistry and Fralin Life Science Institute , Vector-Borne Disease Division, Virginia Polytechnic Institute and State University , Blacksburg , VA , USA
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41
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Li GM. Clamping down on mismatches. eLife 2016; 5. [PMID: 27402202 PMCID: PMC4942253 DOI: 10.7554/elife.18365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 06/29/2016] [Indexed: 11/13/2022] Open
Abstract
A sliding clamp complex may help correct DNA replication errors by keeping track of which DNA strand is new and which is the template.
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Affiliation(s)
- Guo-Min Li
- Department of Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, United States
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42
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Guo J, Gu L, Leffak M, Li GM. MutSβ promotes trinucleotide repeat expansion by recruiting DNA polymerase β to nascent (CAG)n or (CTG)n hairpins for error-prone DNA synthesis. Cell Res 2016; 26:775-86. [PMID: 27255792 PMCID: PMC5129881 DOI: 10.1038/cr.2016.66] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 05/15/2016] [Accepted: 05/17/2016] [Indexed: 12/12/2022] Open
Abstract
Expansion of (CAG)•(CTG) repeats causes a number of familial neurodegenerative disorders. Although the underlying mechanism remains largely unknown, components involved in DNA mismatch repair, particularly mismatch recognition protein MutSβ (a MSH2-MSH3 heterodimer), are implicated in (CAG)•(CTG) repeat expansion. In addition to recognizing small insertion-deletion loop-outs, MutSβ also specifically binds DNA hairpin imperfect heteroduplexes formed within (CAG)n•(CTG)n sequences. However, whether or not and how MutSβ binding triggers expansion of (CAG)•(CTG) repeats remain unknown. We show here that purified recombinant MutSβ physically interacts with DNA polymerase β (Polβ) and stimulates Polβ-catalyzed (CAG)n or (CTG)n hairpin retention. Consistent with these in vitro observations, MutSβ and Polβ interact with each other in vivo, and colocalize at (CAG)•(CTG) repeats during DNA replication. Our data support a model for error-prone processing of (CAG)n or (CTG)n hairpins by MutSβ and Polβ during DNA replication and/or repair: MutSβ recognizes (CAG)n or (CTG)n hairpins formed in the nascent DNA strand, and recruits Polβ to the complex, which then utilizes the hairpin as a primer for extension, leading to (CAG)•(CTG) repeat expansion. This study provides a novel mechanism for trinucleotide repeat expansion in both dividing and non-dividing cells.
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Affiliation(s)
- Jinzhen Guo
- Department of Basic Medical Sciences, Tsinghua University School of Medicine, Beijing 100084, China.,Department of Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, 1450 Biggy Street, Los Angeles, CA 90033, USA
| | - Liya Gu
- Department of Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, 1450 Biggy Street, Los Angeles, CA 90033, USA
| | - Michael Leffak
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
| | - Guo-Min Li
- Department of Basic Medical Sciences, Tsinghua University School of Medicine, Beijing 100084, China.,Department of Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, 1450 Biggy Street, Los Angeles, CA 90033, USA
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43
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Buehler J, Zeltzer S, Reitsma J, Petrucelli A, Umashankar M, Rak M, Zagallo P, Schroeder J, Terhune S, Goodrum F. Opposing Regulation of the EGF Receptor: A Molecular Switch Controlling Cytomegalovirus Latency and Replication. PLoS Pathog 2016; 12:e1005655. [PMID: 27218650 PMCID: PMC4878804 DOI: 10.1371/journal.ppat.1005655] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 05/02/2016] [Indexed: 12/15/2022] Open
Abstract
Herpesviruses persist indefinitely in their host through complex and poorly defined interactions that mediate latent, chronic or productive states of infection. Human cytomegalovirus (CMV or HCMV), a ubiquitous β-herpesvirus, coordinates the expression of two viral genes, UL135 and UL138, which have opposing roles in regulating viral replication. UL135 promotes reactivation from latency and virus replication, in part, by overcoming replication-suppressive effects of UL138. The mechanism by which UL135 and UL138 oppose one another is not known. We identified viral and host proteins interacting with UL138 protein (pUL138) to begin to define the mechanisms by which pUL135 and pUL138 function. We show that pUL135 and pUL138 regulate the viral cycle by targeting that same receptor tyrosine kinase (RTK) epidermal growth factor receptor (EGFR). EGFR is a major homeostatic regulator involved in cellular proliferation, differentiation, and survival, making it an ideal target for viral manipulation during infection. pUL135 promotes internalization and turnover of EGFR from the cell surface, whereas pUL138 preserves surface expression and activation of EGFR. We show that activated EGFR is sequestered within the infection-induced, juxtanuclear viral assembly compartment and is unresponsive to stress. Intriguingly, these findings suggest that CMV insulates active EGFR in the cell and that pUL135 and pUL138 function to fine-tune EGFR levels at the cell surface to allow the infected cell to respond to extracellular cues. Consistent with the role of pUL135 in promoting replication, inhibition of EGFR or the downstream phosphoinositide 3-kinase (PI3K) favors reactivation from latency and replication. We propose a model whereby pUL135 and pUL138 together with EGFR comprise a molecular switch that regulates states of latency and replication in HCMV infection by regulating EGFR trafficking to fine tune EGFR signaling. Cytomegalovirus, a herpesvirus, persists in its host through complex interactions that mediate latent, chronic or productive states of infection. Defining the mechanistic basis viral persistence is important for defining the costs and possible benefits of viral persistence and to mitigate pathologies associated with reactivation. We have identified two genes, UL135 and UL138, with opposing roles in regulating states of latency and replication. UL135 promotes replication and reactivation from latency, in part, by overcoming suppressive effects of UL138. Intriguingly, pUL135 and pUL138 regulate the viral cycle by targeting the same receptor tyrosine kinase, epidermal growth factor receptor (EGFR). EGFR is a major homeostatic regulator controlling cellular proliferation, differentiation, and survival, making it an ideal target for viruses to manipulate during infection. We show that CMV insulates and regulates EGFR levels and activity by modulating its trafficking. This work defines a molecular switch that regulates latent and replicative states of infection through the modulation of host trafficking and signaling pathways. The regulation of EGFR at the cell surface provides a novel means by which the virus may sense and respond to changes in the host environment to enter into or exit the latent state.
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Affiliation(s)
- Jason Buehler
- BIO5 Institute, University of Arizona, Tucson, Arizona, United States of America
| | - Sebastian Zeltzer
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, Arizona, United States of America
| | - Justin Reitsma
- Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Alex Petrucelli
- Department of Immunobiology, University of Arizona, Tucson, Arizona, United States of America
| | | | - Mike Rak
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, Arizona, United States of America
| | - Patricia Zagallo
- Department of Immunobiology, University of Arizona, Tucson, Arizona, United States of America
| | - Joyce Schroeder
- BIO5 Institute, University of Arizona, Tucson, Arizona, United States of America
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona, United States of America
- University of Arizona Cancer Center, University of Arizona, Tucson, Arizona, United States of America
| | - Scott Terhune
- Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Felicia Goodrum
- BIO5 Institute, University of Arizona, Tucson, Arizona, United States of America
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, Arizona, United States of America
- Department of Immunobiology, University of Arizona, Tucson, Arizona, United States of America
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona, United States of America
- University of Arizona Cancer Center, University of Arizona, Tucson, Arizona, United States of America
- * E-mail:
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44
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Chen MK, Hung MC. Regulation of therapeutic resistance in cancers by receptor tyrosine kinases. Am J Cancer Res 2016; 6:827-842. [PMID: 27186434 PMCID: PMC4859887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 03/06/2016] [Indexed: 06/05/2023] Open
Abstract
In response to DNA damage lesions due to cellular stress, DNA damage response (DDR) pathways are activated to promote cell survival and genetic stability or unrepaired lesion-induced cell death. Current cancer treatments predominantly utilize DNA damaging agents, such as irradiation and chemotherapy drugs, to inhibit cancer cell proliferation and induce cell death through the activation of DDR. However, a portion of cancer patients is reported to develop therapeutic resistance to these DDR-inducing agents. One significant resistance mechanism in cancer cells is oncogenic kinase overexpression, which promotes cell survival by enhancing DNA damage repair pathways and evading cell cycle arrest. Among the oncogenic kinases, overexpression of receptor tyrosine kinases (RTKs) is reported in many of solid tumors, and numerous clinical trials targeting RTKs are currently in progress. As the emerging trend in cancer treatment combines DNA damaging agents and RTK inhibitors, it is important to understand the substrates of RTKs relative to the DDR pathways. In addition, alteration of RTK expression and their phosphorylated substrates can serve as biomarkers to stratify patients for combination therapies. In this review, we summarize the deleterious effects of RTKs on the DDR pathways and the emerging biomarkers for personalized therapy.
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Affiliation(s)
- Mei-Kuang Chen
- Graduate School of Biomedical Science, The University of Texas Health Science Center at HoustonHouston, Texas 77030, USA
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer CenterHouston, Texas, 77030, USA
| | - Mien-Chie Hung
- Graduate School of Biomedical Science, The University of Texas Health Science Center at HoustonHouston, Texas 77030, USA
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer CenterHouston, Texas, 77030, USA
- Center of Molecular Medicine and Graduate Institute of Cancer Biology, China Medical UniversityTaichung 404, Taiwan
- Department of Biotechnology, Asia UniversityTaichung 413, Taiwan
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45
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Li X, Fan X, Li D, Zeng X, Zeng H, Wang Y, Zhou Y, Chen Y, Huang M, Bi H. Schisandra sphenanthera Extract Facilitates Liver Regeneration after Partial Hepatectomy in Mice. ACTA ACUST UNITED AC 2016; 44:647-52. [PMID: 26932815 DOI: 10.1124/dmd.115.068288] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Accepted: 02/26/2016] [Indexed: 01/20/2023]
Abstract
Liver regeneration after surgical liver resection is crucial for the restoration of liver mass and the recovery of liver function.Schisandra sphenanthera extract (Wuzhi tablet, WZ) is a preparation of an extract from the dried ripe fruit of Schisandra sphenanthera Rehd. et Wils, a traditional hepatoprotective herb. Previously, we found that WZ could induce liver regeneration-related genes against acetaminophen-induced liver injury. However, whether WZ can directly facilitate liver regeneration after liver resection remains unknown. We investigated whether WZ has potential in promoting liver regeneration after a partial hepatectomy (PHX) in mice. Remnant livers were collected 1, 1.5, 2, 3, 5, 7, and 10 days after PHX. Hepatocyte proliferation was assessed using the Ki-67 labeling index. Western blot analysis was performed on proteins known to be involved in liver regeneration. The results demonstrated that WZ significantly increased the liver-to-body weight ratio of mice after PHX but had no effect on that of mice after a sham operation. Additionally, the peak hepatocyte proliferation was observed at 1.5 days in PHX/WZ-treated mice but at 2 days in PHX/saline-treated mice, as evidenced by the Ki-67 positive ratio. Furthermore, WZ significantly increased the protein expression of ligand-induced phosphorylation of epidermal growth factor receptor and up-regulated cyclin D1, cyclin D-dependent kinase 4, phosphorylated retinoblastoma, and proliferating cell nuclear antigen protein expression and down-regulated the expression of cell cycle inhibitors p21 and p27 in the regenerative process after PHX. These results demonstrate that WZ significantly facilitates hepatocyte proliferation and liver regeneration after PHX.
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Affiliation(s)
- Xi Li
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou (X.L., D.L., X.Z., H.Z., Y.W., Y.Z., Y.C., M.H., H.B.); Shenzhen Bao'an Maternal and Child Health Hospital, Shenzhen (X.F.), People's Republic of China
| | - Xiaomei Fan
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou (X.L., D.L., X.Z., H.Z., Y.W., Y.Z., Y.C., M.H., H.B.); Shenzhen Bao'an Maternal and Child Health Hospital, Shenzhen (X.F.), People's Republic of China
| | - Dongshun Li
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou (X.L., D.L., X.Z., H.Z., Y.W., Y.Z., Y.C., M.H., H.B.); Shenzhen Bao'an Maternal and Child Health Hospital, Shenzhen (X.F.), People's Republic of China
| | - Xuezhen Zeng
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou (X.L., D.L., X.Z., H.Z., Y.W., Y.Z., Y.C., M.H., H.B.); Shenzhen Bao'an Maternal and Child Health Hospital, Shenzhen (X.F.), People's Republic of China
| | - Hang Zeng
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou (X.L., D.L., X.Z., H.Z., Y.W., Y.Z., Y.C., M.H., H.B.); Shenzhen Bao'an Maternal and Child Health Hospital, Shenzhen (X.F.), People's Republic of China
| | - Yongtao Wang
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou (X.L., D.L., X.Z., H.Z., Y.W., Y.Z., Y.C., M.H., H.B.); Shenzhen Bao'an Maternal and Child Health Hospital, Shenzhen (X.F.), People's Republic of China
| | - Yawen Zhou
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou (X.L., D.L., X.Z., H.Z., Y.W., Y.Z., Y.C., M.H., H.B.); Shenzhen Bao'an Maternal and Child Health Hospital, Shenzhen (X.F.), People's Republic of China
| | - Yixin Chen
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou (X.L., D.L., X.Z., H.Z., Y.W., Y.Z., Y.C., M.H., H.B.); Shenzhen Bao'an Maternal and Child Health Hospital, Shenzhen (X.F.), People's Republic of China
| | - Min Huang
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou (X.L., D.L., X.Z., H.Z., Y.W., Y.Z., Y.C., M.H., H.B.); Shenzhen Bao'an Maternal and Child Health Hospital, Shenzhen (X.F.), People's Republic of China
| | - Huichang Bi
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou (X.L., D.L., X.Z., H.Z., Y.W., Y.Z., Y.C., M.H., H.B.); Shenzhen Bao'an Maternal and Child Health Hospital, Shenzhen (X.F.), People's Republic of China
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46
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Friedhoff P, Li P, Gotthardt J. Protein-protein interactions in DNA mismatch repair. DNA Repair (Amst) 2015; 38:50-57. [PMID: 26725162 DOI: 10.1016/j.dnarep.2015.11.013] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 11/11/2015] [Accepted: 11/30/2015] [Indexed: 11/25/2022]
Abstract
The principal DNA mismatch repair proteins MutS and MutL are versatile enzymes that couple DNA mismatch or damage recognition to other cellular processes. Besides interaction with their DNA substrates this involves transient interactions with other proteins which is triggered by the DNA mismatch or damage and controlled by conformational changes. Both MutS and MutL proteins have ATPase activity, which adds another level to control their activity and interactions with DNA substrates and other proteins. Here we focus on the protein-protein interactions, protein interaction sites and the different levels of structural knowledge about the protein complexes formed with MutS and MutL during the mismatch repair reaction.
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Affiliation(s)
- Peter Friedhoff
- Institute for Biochemistry FB 08, Justus Liebig University, Heinrich-Buff-Ring 17, D-35392 Giessen, Germany.
| | - Pingping Li
- Institute for Biochemistry FB 08, Justus Liebig University, Heinrich-Buff-Ring 17, D-35392 Giessen, Germany
| | - Julia Gotthardt
- Institute for Biochemistry FB 08, Justus Liebig University, Heinrich-Buff-Ring 17, D-35392 Giessen, Germany
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47
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Regulation of mismatch repair by histone code and posttranslational modifications in eukaryotic cells. DNA Repair (Amst) 2015; 38:68-74. [PMID: 26719139 DOI: 10.1016/j.dnarep.2015.11.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Revised: 09/09/2015] [Accepted: 11/30/2015] [Indexed: 12/15/2022]
Abstract
DNA mismatch repair (MMR) protects genome integrity by correcting DNA replication-associated mispairs, modulating DNA damage-induced cell cycle checkpoints and regulating homeologous recombination. Loss of MMR function leads to cancer development. This review describes progress in understanding how MMR is carried out in the context of chromatin and how chromatin organization/compaction, epigenetic mechanisms and posttranslational modifications of MMR proteins influence and regulate MMR in eukaryotic cells.
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48
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Mahajan K, Mahajan NP. Cross talk of tyrosine kinases with the DNA damage signaling pathways. Nucleic Acids Res 2015; 43:10588-601. [PMID: 26546517 PMCID: PMC4678820 DOI: 10.1093/nar/gkv1166] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 10/21/2015] [Indexed: 01/19/2023] Open
Abstract
Tyrosine kinases respond to extracellular and intracellular cues by activating specific cellular signaling cascades to regulate cell cycle, growth, proliferation, differentiation and survival. Likewise, DNA damage response proteins (DDR) activated by DNA lesions or chromatin alterations recruit the DNA repair and cell cycle checkpoint machinery to restore genome integrity and cellular homeostasis. Several new examples have been uncovered in recent studies which reveal novel epigenetic and non-epigenetic mechanisms by which tyrosine kinases interact with DDR proteins to dictate cell fate, i.e. survival or apoptosis, following DNA damage. These studies reveal the ability of tyrosine kinases to directly regulate the activity of DNA repair and cell cycle check point proteins by tyrosine phosphorylation. In addition, tyrosine kinases epigenetically regulate DNA damage signaling pathways by modifying the core histones as well as chromatin modifiers at critical tyrosine residues. Thus, deregulated tyrosine kinase driven epigenomic alterations have profound implications in cancer, aging and genetic disorders. Consequently, targeting oncogenic tyrosine kinase induced epigenetic alterations has gained significant traction in overcoming cancer cell resistance to various therapies. This review discusses mechanisms by which tyrosine kinases interact with DDR pathways to regulate processes critical for maintaining genome integrity as well as clinical strategies for targeted cancer therapies.
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Affiliation(s)
- Kiran Mahajan
- Tumor Biology Department, Moffitt Cancer Center, 12902 Magnolia Drive, Tampa, FL 33612, USA Department of Oncological Sciences, University of South Florida, 12902 Magnolia Drive, Tampa, FL 33612, USA
| | - Nupam P Mahajan
- Drug Discovery Department, Moffitt Cancer Center, University of South Florida, 12902 Magnolia Drive, Tampa, FL 33612, USA Department of Oncological Sciences, University of South Florida, 12902 Magnolia Drive, Tampa, FL 33612, USA
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49
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Chattopadhyay S, Veleeparambil M, Poddar D, Abdulkhalek S, Bandyopadhyay SK, Fensterl V, Sen GC. EGFR kinase activity is required for TLR4 signaling and the septic shock response. EMBO Rep 2015; 16:1535-47. [PMID: 26341626 DOI: 10.15252/embr.201540337] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Accepted: 08/17/2015] [Indexed: 01/06/2023] Open
Abstract
Mammalian Toll-like receptors (TLR) recognize microbial products and elicit transient immune responses that protect the infected host from disease. TLR4--which signals from both plasma and endosomal membranes--is activated by bacterial lipopolysaccharides (LPS) and induces many cytokine genes, the prolonged expression of which causes septic shock in mice. We report here that the expression of some TLR4-induced genes in myeloid cells requires the protein kinase activity of the epidermal growth factor receptor (EGFR). EGFR inhibition affects TLR4-induced responses differently depending on the target gene. The induction of interferon-β (IFN-β) and IFN-inducible genes is strongly inhibited, whereas TNF-α induction is enhanced. Inhibition is specific to the IFN-regulatory factor (IRF)-driven genes because EGFR is required for IRF activation downstream of TLR--as is IRF co-activator β-catenin--through the PI3 kinase/AKT pathway. Administration of an EGFR inhibitor to mice protects them from LPS-induced septic shock and death by selectively blocking the IFN branch of TLR4 signaling. These results demonstrate a selective regulation of TLR4 signaling by EGFR and highlight the potential use of EGFR inhibitors to treat septic shock syndrome.
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Affiliation(s)
- Saurabh Chattopadhyay
- Department of Molecular Genetics, Lerner Research Institute Cleveland Clinic, Cleveland, OH, USA
| | - Manoj Veleeparambil
- Department of Molecular Genetics, Lerner Research Institute Cleveland Clinic, Cleveland, OH, USA
| | - Darshana Poddar
- Department of Molecular Genetics, Lerner Research Institute Cleveland Clinic, Cleveland, OH, USA
| | - Samar Abdulkhalek
- Department of Molecular Genetics, Lerner Research Institute Cleveland Clinic, Cleveland, OH, USA
| | - Sudip K Bandyopadhyay
- Department of Molecular Genetics, Lerner Research Institute Cleveland Clinic, Cleveland, OH, USA
| | - Volker Fensterl
- Department of Molecular Genetics, Lerner Research Institute Cleveland Clinic, Cleveland, OH, USA
| | - Ganes C Sen
- Department of Molecular Genetics, Lerner Research Institute Cleveland Clinic, Cleveland, OH, USA
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50
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Chen MK, Hung MC. Proteolytic cleavage, trafficking, and functions of nuclear receptor tyrosine kinases. FEBS J 2015; 282:3693-721. [PMID: 26096795 DOI: 10.1111/febs.13342] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 05/18/2015] [Accepted: 06/09/2015] [Indexed: 01/18/2023]
Abstract
Intracellular localization has been reported for over three-quarters of receptor tyrosine kinase (RTK) families in response to environmental stimuli. Internalized RTK may bind to non-canonical substrates and affect various cellular processes. Many of the intracellular RTKs exist as fragmented forms that are generated by γ-secretase cleavage of the full-length receptor, shedding, alternative splicing, or alternative translation initiation. Soluble RTK fragments are stabilized and intracellularly transported into subcellular compartments, such as the nucleus, by binding to chaperone or transcription factors, while membrane-bound RTKs (full-length or truncated) are transported from the plasma membrane to the ER through the well-established Rab- or clathrin adaptor protein-coated vesicle retrograde trafficking pathways. Subsequent nuclear transport of membrane-bound RTK may occur via two pathways, INFS or INTERNET, with the former characterized by release of receptors from the ER into the cytosol and the latter characterized by release of membrane-bound receptor from the ER into the nucleoplasm through the inner nuclear membrane. Although most non-canonical intracellular RTK signaling is related to transcriptional regulation, there may be other functions that have yet to be discovered. In this review, we summarize the proteolytic processing, intracellular trafficking and nuclear functions of RTKs, and discuss how they promote cancer progression, and their clinical implications.
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Affiliation(s)
- Mei-Kuang Chen
- The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX, USA.,Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Mien-Chie Hung
- The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX, USA.,Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.,Center of Molecular Medicine and Graduate Institute of Cancer Biology, China Medical University, Taichung, Taiwan.,Department of Biotechnology, Asia University, Taichung, Taiwan
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