1
|
Ostroverkhova D, Tyryshkin K, Beach AK, Moore EA, Masoudi-Sobhanzadeh Y, Barbari SR, Rogozin IB, Shaitan KV, Panchenko AR, Shcherbakova PV. DNA polymerase ε and δ variants drive mutagenesis in polypurine tracts in human tumors. Cell Rep 2024; 43:113655. [PMID: 38219146 PMCID: PMC10830898 DOI: 10.1016/j.celrep.2023.113655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 11/07/2023] [Accepted: 12/19/2023] [Indexed: 01/16/2024] Open
Abstract
Alterations in the exonuclease domain of DNA polymerase ε cause ultramutated cancers. These cancers accumulate AGA>ATA transversions; however, their genomic features beyond the trinucleotide motifs are obscure. We analyze the extended DNA context of ultramutation using whole-exome sequencing data from 524 endometrial and 395 colorectal tumors. We find that G>T transversions in POLE-mutant tumors predominantly affect sequences containing at least six consecutive purines, with a striking preference for certain positions within polypurine tracts. Using this signature, we develop a machine-learning classifier to identify tumors with hitherto unknown POLE drivers and validate two drivers, POLE-E978G and POLE-S461L, by functional assays in yeast. Unlike other pathogenic variants, the E978G substitution affects the polymerase domain of Pol ε. We further show that tumors with POLD1 drivers share the extended signature of POLE ultramutation. These findings expand the understanding of ultramutation mechanisms and highlight peculiar mutagenic properties of polypurine tracts in the human genome.
Collapse
Affiliation(s)
- Daria Ostroverkhova
- Department of Pathology and Molecular Medicine, School of Medicine, Queen's University, Kingston, ON, Canada
| | - Kathrin Tyryshkin
- Department of Pathology and Molecular Medicine, School of Medicine, Queen's University, Kingston, ON, Canada
| | - Annette K Beach
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
| | - Elizabeth A Moore
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
| | - Yosef Masoudi-Sobhanzadeh
- Department of Pathology and Molecular Medicine, School of Medicine, Queen's University, Kingston, ON, Canada
| | - Stephanie R Barbari
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
| | - Igor B Rogozin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | | | - Anna R Panchenko
- Department of Pathology and Molecular Medicine, School of Medicine, Queen's University, Kingston, ON, Canada.
| | - Polina V Shcherbakova
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA.
| |
Collapse
|
2
|
Crevel G, Kearsey S, Cotterill S. A simple bypass assay for DNA polymerases shows that cancer-associated hypermutating variants exhibit differences in vitro. FEBS J 2023; 290:5744-5758. [PMID: 37592814 PMCID: PMC10953417 DOI: 10.1111/febs.16936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 07/13/2023] [Accepted: 08/16/2023] [Indexed: 08/19/2023]
Abstract
Errors made by DNA polymerases contribute to both natural variation and, in extreme cases, genome instability and its associated diseases. Recently, the importance of polymerase misincorporation in disease has been highlighted by the identification of cancer-associated polymerase variants with mutations in the exonuclease domain. A subgroup of these variants have a hypermutation phenotype in tumours, and when modelled in yeast, they show mutation rates in excess of that seen with polymerase with simple loss of proofreading activity. We have developed a bypass assay to rapidly determine the tendency of a polymerase to misincorporate in vitro. We have used the assay to compare misincorporation by wild-type, exonuclease-defective and two hypermutating human DNA polymerase ε variants, P286R and V411L. The assay clearly distinguished between the misincorporation rates of wild-type, exonuclease dead and P286R polymerases. However, the V411L polymerase showed misincorporation rate comparable to the exonuclease dead enzyme rather than P286R, suggesting that there may be some differences in the way that these variants cause hypermutation. Using this assay, misincorporation opposite a templated C nucleotide was consistently higher than for other nucleotides, and this caused predominantly C-to-T transitions. This is consistent with the observation that C-to-T transitions are commonly seen in DNA polymerase ε mutant tumours.
Collapse
|
3
|
Li J, Stenberg S, Yue JX, Mikhalev E, Thompson D, Warringer J, Liti G. Genome instability footprint under rapamycin and hydroxyurea treatments. PLoS Genet 2023; 19:e1011012. [PMID: 37931001 PMCID: PMC10653606 DOI: 10.1371/journal.pgen.1011012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 11/16/2023] [Accepted: 10/10/2023] [Indexed: 11/08/2023] Open
Abstract
The mutational processes dictating the accumulation of mutations in genomes are shaped by genetic background, environment and their interactions. Accurate quantification of mutation rates and spectra under drugs has important implications in disease treatment. Here, we used whole-genome sequencing and time-resolved growth phenotyping of yeast mutation accumulation lines to give a detailed view of the mutagenic effects of rapamycin and hydroxyurea on the genome and cell growth. Mutation rates depended on the genetic backgrounds but were only marginally affected by rapamycin. As a remarkable exception, rapamycin treatment was associated with frequent chromosome XII amplifications, which compensated for rapamycin induced rDNA repeat contraction on this chromosome and served to maintain rDNA content homeostasis and fitness. In hydroxyurea, a wide range of mutation rates were elevated regardless of the genetic backgrounds, with a particularly high occurrence of aneuploidy that associated with dramatic fitness loss. Hydroxyurea also induced a high T-to-G and low C-to-A transversion rate that reversed the common G/C-to-A/T bias in yeast and gave rise to a broad range of structural variants, including mtDNA deletions. The hydroxyurea mutation footprint was consistent with the activation of error-prone DNA polymerase activities and non-homologues end joining repair pathways. Taken together, our study provides an in-depth view of mutation rates and signatures in rapamycin and hydroxyurea and their impact on cell fitness, which brings insights for assessing their chronic effects on genome integrity.
Collapse
Affiliation(s)
- Jing Li
- State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, P. R. China
- Université Côte d’Azur, CNRS, INSERM, IRCAN, Nice, France
| | - Simon Stenberg
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Jia-Xing Yue
- State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, P. R. China
- Université Côte d’Azur, CNRS, INSERM, IRCAN, Nice, France
| | | | - Dawn Thompson
- Ginkgo Bioworks, Boston, Massachusetts, United States of America
| | - Jonas Warringer
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Gianni Liti
- Université Côte d’Azur, CNRS, INSERM, IRCAN, Nice, France
| |
Collapse
|
4
|
Barbari SR, Beach AK, Markgren JG, Parkash V, Moore EA, Johansson E, Shcherbakova PV. Enhanced polymerase activity permits efficient synthesis by cancer-associated DNA polymerase ϵ variants at low dNTP levels. Nucleic Acids Res 2022; 50:8023-8040. [PMID: 35822874 PMCID: PMC9371911 DOI: 10.1093/nar/gkac602] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 06/13/2022] [Accepted: 06/29/2022] [Indexed: 11/28/2022] Open
Abstract
Amino acid substitutions in the exonuclease domain of DNA polymerase ϵ (Polϵ) cause ultramutated tumors. Studies in model organisms suggested pathogenic mechanisms distinct from a simple loss of exonuclease. These mechanisms remain unclear for most recurrent Polϵ mutations. Particularly, the highly prevalent V411L variant remained a long-standing puzzle with no detectable mutator effect in yeast despite the unequivocal association with ultramutation in cancers. Using purified four-subunit yeast Polϵ, we assessed the consequences of substitutions mimicking human V411L, S459F, F367S, L424V and D275V. While the effects on exonuclease activity vary widely, all common cancer-associated variants have increased DNA polymerase activity. Notably, the analog of Polϵ-V411L is among the strongest polymerases, and structural analysis suggests defective polymerase-to-exonuclease site switching. We further show that the V411L analog produces a robust mutator phenotype in strains that lack mismatch repair, indicating a high rate of replication errors. Lastly, unlike wild-type and exonuclease-dead Polϵ, hyperactive variants efficiently synthesize DNA at low dNTP concentrations. We propose that this characteristic could promote cancer cell survival and preferential participation of mutator polymerases in replication during metabolic stress. Our results support the notion that polymerase fitness, rather than low fidelity alone, is an important determinant of variant pathogenicity.
Collapse
Affiliation(s)
- Stephanie R Barbari
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Annette K Beach
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Joel G Markgren
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
| | - Vimal Parkash
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
| | - Elizabeth A Moore
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Erik Johansson
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
| | - Polina V Shcherbakova
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| |
Collapse
|
5
|
Efficient discrimination against RNA-containing primers by human DNA polymerase ε. Sci Rep 2022; 12:10163. [PMID: 35715491 PMCID: PMC9205888 DOI: 10.1038/s41598-022-14602-2] [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: 03/30/2022] [Accepted: 06/09/2022] [Indexed: 01/13/2023] Open
Abstract
DNA polymerase ε (Polε) performs bulk synthesis of DNA on the leading strand during genome replication. Polε binds two substrates, a template:primer and dNTP, and catalyzes a covalent attachment of dNMP to the 3' end of the primer. Previous studies have shown that Polε easily inserts and extends ribonucleotides, which may promote mutagenesis and genome instability. In this work, we analyzed the mechanisms of discrimination against RNA-containing primers by human Polε (hPolε), performing binding and kinetic studies at near-physiological salt concentration. Pre-steady-state kinetic studies revealed that hPolεCD extends RNA primers with approximately 3300-fold lower efficiency in comparison to DNA, and addition of one dNMP to the 3' end of an RNA primer increases activity 36-fold. Likewise, addition of one rNMP to the 3' end of a DNA primer reduces activity 38-fold. The binding studies conducted in the presence of 0.15 M NaCl revealed that human hPolεCD has low affinity to DNA (KD of 1.5 µM). Strikingly, a change of salt concentration from 0.1 M to 0.15 M reduces the stability of the hPolεCD/DNA complex by 25-fold. Upon template:primer binding, the incoming dNTP and magnesium ions make hPolε discriminative against RNA and chimeric RNA-DNA primers. In summary, our studies revealed that hPolε discrimination against RNA-containing primers is based on the following factors: incoming dNTP, magnesium ions, a steric gate for the primer 2'OH, and the rigid template:primer binding pocket near the catalytic site. In addition, we showed the importance of conducting functional studies at near-physiological salt concentration.
Collapse
|
6
|
Polymerase Epsilon-Associated Ultramutagenesis in Cancer. Cancers (Basel) 2022; 14:cancers14061467. [PMID: 35326618 PMCID: PMC8946778 DOI: 10.3390/cancers14061467] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 03/09/2022] [Accepted: 03/09/2022] [Indexed: 01/27/2023] Open
Abstract
With advances in next generation sequencing (NGS) technologies, efforts have been made to develop personalized medicine, targeting the specific genetic makeup of an individual. Somatic or germline DNA Polymerase epsilon (PolE) mutations cause ultramutated (>100 mutations/Mb) cancer. In contrast to mismatch repair-deficient hypermutated (>10 mutations/Mb) cancer, PolE-associated cancer is primarily microsatellite stable (MSS) In this article, we provide a comprehensive review of this PolE-associated ultramutated tumor. We describe its molecular characteristics, including the mutation sites and mutation signature of this type of tumor and the mechanism of its ultramutagenesis. We discuss its good clinical prognosis and elucidate the mechanism for enhanced immunogenicity with a high tumor mutation burden, increased neoantigen load, and enriched tumor-infiltrating lymphocytes. We also provide the rationale for immune checkpoint inhibitors in PolE-mutated tumors.
Collapse
|
7
|
Park VS, Sun MJS, Frey WD, Williams LG, Hodel KP, Strauss JD, Wellens SJ, Jackson JG, Pursell ZF. Mouse model and human patient data reveal critical roles for Pten and p53 in suppressing POLE mutant tumor development. NAR Cancer 2022; 4:zcac004. [PMID: 35252866 PMCID: PMC8892059 DOI: 10.1093/narcan/zcac004] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 01/17/2022] [Accepted: 02/17/2022] [Indexed: 12/24/2022] Open
Abstract
Mutations in the exonuclease domain of POLE are associated with tumors harboring very high mutation burdens. The mechanisms linking this significant mutation accumulation and tumor development remain poorly understood. Pole+/P286R;Trp53+/– mice showed accelerated cancer mortality compared to Pole+/P286R;Trp53+/+ mice. Cells from Pole+/P286R mice showed increased p53 activation, and subsequent loss of p53 permitted rapid growth, implicating canonical p53 loss of heterozygosity in POLE mutant tumor growth. However, p53 status had no effect on tumor mutation burden or single base substitution signatures in POLE mutant tumors from mice or humans. Pten has important roles in maintaining genome stability. We find that PTEN mutations are highly enriched in human POLE mutant tumors, including many in POLE signature contexts. One such signature mutation, PTEN-F341V, was previously shown in a mouse model to specifically decrease nuclear Pten and lead to increased DNA damage. We found tumors in Pole+/P286R mice that spontaneously acquired PtenF341V mutations and were associated with significantly reduced nuclear Pten and elevated DNA damage. Re-analysis of human TCGA (The Cancer Genome Atlas) data showed that all PTEN-F341V mutations occurred in tumors with mutations in POLE. Taken together with recent published work, our results support the idea that development of POLE mutant tumors may involve disabling surveillance of nuclear DNA damage in addition to POLE-mediated hypermutagenesis.
Collapse
Affiliation(s)
- Vivian S Park
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Meijuan J S Sun
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Wesley D Frey
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Leonard G Williams
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Karl P Hodel
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Juliet D Strauss
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Sydney J Wellens
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA
| | - James G Jackson
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Zachary F Pursell
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA
| |
Collapse
|
8
|
Soriano I, Vazquez E, De Leon N, Bertrand S, Heitzer E, Toumazou S, Bo Z, Palles C, Pai CC, Humphrey TC, Tomlinson I, Cotterill S, Kearsey SE. Expression of the cancer-associated DNA polymerase ε P286R in fission yeast leads to translesion synthesis polymerase dependent hypermutation and defective DNA replication. PLoS Genet 2021; 17:e1009526. [PMID: 34228709 PMCID: PMC8284607 DOI: 10.1371/journal.pgen.1009526] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 07/16/2021] [Accepted: 06/11/2021] [Indexed: 12/15/2022] Open
Abstract
Somatic and germline mutations in the proofreading domain of the replicative DNA polymerase ε (POLE-exonuclease domain mutations, POLE-EDMs) are frequently found in colorectal and endometrial cancers and, occasionally, in other tumours. POLE-associated cancers typically display hypermutation, and a unique mutational signature, with a predominance of C > A transversions in the context TCT and C > T transitions in the context TCG. To understand better the contribution of hypermutagenesis to tumour development, we have modelled the most recurrent POLE-EDM (POLE-P286R) in Schizosaccharomyces pombe. Whole-genome sequencing analysis revealed that the corresponding pol2-P287R allele also has a strong mutator effect in vivo, with a high frequency of base substitutions and relatively few indel mutations. The mutations are equally distributed across different genomic regions, but in the immediate vicinity there is an asymmetry in AT frequency. The most abundant base-pair changes are TCT > TAT transversions and, in contrast to human mutations, TCG > TTG transitions are not elevated, likely due to the absence of cytosine methylation in fission yeast. The pol2-P287R variant has an increased sensitivity to elevated dNTP levels and DNA damaging agents, and shows reduced viability on depletion of the Pfh1 helicase. In addition, S phase is aberrant and RPA foci are elevated, suggestive of ssDNA or DNA damage, and the pol2-P287R mutation is synthetically lethal with rad3 inactivation, indicative of checkpoint activation. Significantly, deletion of genes encoding some translesion synthesis polymerases, most notably Pol κ, partially suppresses pol2-P287R hypermutation, indicating that polymerase switching contributes to this phenotype.
Collapse
Affiliation(s)
- Ignacio Soriano
- ZRAB, University of Oxford, Oxford, United Kingdom
- Edinburgh Cancer Research Centre, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Enrique Vazquez
- Genomics Unit, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Nagore De Leon
- ZRAB, University of Oxford, Oxford, United Kingdom
- Edinburgh Cancer Research Centre, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | | | - Ellen Heitzer
- Institute of Human Genetics, Diagnostic & Research Center for Molecular BioMedicine, Medical University of Graz, Graz, Austria
| | - Sophia Toumazou
- ZRAB, University of Oxford, Oxford, United Kingdom
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Zhihan Bo
- ZRAB, University of Oxford, Oxford, United Kingdom
| | - Claire Palles
- Gastrointestinal Cancer Genetics Laboratory, Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Chen-Chun Pai
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Timothy C. Humphrey
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Ian Tomlinson
- Edinburgh Cancer Research Centre, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Sue Cotterill
- St. George’s, University of London, Cranmer Terrace, Tooting, London, United Kingdom
| | | |
Collapse
|