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Son K, Takhaveev V, Mor V, Yu H, Dillier E, Zilio N, Püllen NJL, Ivanov D, Ulrich HD, Sturla SJ, Schärer OD. Trabectedin derails transcription-coupled nucleotide excision repair to induce DNA breaks in highly transcribed genes. Nat Commun 2024; 15:1388. [PMID: 38360910 PMCID: PMC10869700 DOI: 10.1038/s41467-024-45664-7] [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: 08/04/2023] [Accepted: 01/30/2024] [Indexed: 02/17/2024] Open
Abstract
Most genotoxic anticancer agents fail in tumors with intact DNA repair. Therefore, trabectedin, anagent more toxic to cells with active DNA repair, specifically transcription-coupled nucleotide excision repair (TC-NER), provides therapeutic opportunities. To unlock the potential of trabectedin and inform its application in precision oncology, an understanding of the mechanism of the drug's TC-NER-dependent toxicity is needed. Here, we determine that abortive TC-NER of trabectedin-DNA adducts forms persistent single-strand breaks (SSBs) as the adducts block the second of the two sequential NER incisions. We map the 3'-hydroxyl groups of SSBs originating from the first NER incision at trabectedin lesions, recording TC-NER on a genome-wide scale. Trabectedin-induced SSBs primarily occur in transcribed strands of active genes and peak near transcription start sites. Frequent SSBs are also found outside gene bodies, connecting TC-NER to divergent transcription from promoters. This work advances the use of trabectedin for precision oncology and for studying TC-NER and transcription.
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Affiliation(s)
- Kook Son
- Center for Genomic Integrity, Institute for Basic Science (IBS), 44919, Ulsan, Republic of Korea
| | - Vakil Takhaveev
- Department of Health Sciences and Technology, ETH Zürich, 8092, Zürich, Switzerland
| | - Visesato Mor
- Center for Genomic Integrity, Institute for Basic Science (IBS), 44919, Ulsan, Republic of Korea
| | - Hobin Yu
- Center for Genomic Integrity, Institute for Basic Science (IBS), 44919, Ulsan, Republic of Korea
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), 44919, Ulsan, Republic of Korea
| | - Emma Dillier
- Department of Health Sciences and Technology, ETH Zürich, 8092, Zürich, Switzerland
| | - Nicola Zilio
- Institute of Molecular Biology (IMB), 55128, Mainz, Germany
| | - Nikolai J L Püllen
- Department of Health Sciences and Technology, ETH Zürich, 8092, Zürich, Switzerland
| | - Dmitri Ivanov
- Center for Genomic Integrity, Institute for Basic Science (IBS), 44919, Ulsan, Republic of Korea
| | - Helle D Ulrich
- Institute of Molecular Biology (IMB), 55128, Mainz, Germany
| | - Shana J Sturla
- Department of Health Sciences and Technology, ETH Zürich, 8092, Zürich, Switzerland.
| | - Orlando D Schärer
- Center for Genomic Integrity, Institute for Basic Science (IBS), 44919, Ulsan, Republic of Korea.
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), 44919, Ulsan, Republic of Korea.
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2
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Lal B, Kulkarni A, McDermott J, Rais R, Alt J, Wu Y, Lopez-Bertoni H, Sall S, Kathad U, Zhou J, Slusher BS, Bhatia K, Laterra J. Preclinical Efficacy of LP-184, a Tumor Site Activated Synthetic Lethal Therapeutic, in Glioblastoma. Clin Cancer Res 2023; 29:4209-4218. [PMID: 37494541 DOI: 10.1158/1078-0432.ccr-23-0673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 06/15/2023] [Accepted: 07/24/2023] [Indexed: 07/28/2023]
Abstract
PURPOSE Glioblastoma (GBM) is the most common brain malignancy with median survival <2 years. Standard-of-care temozolomide has marginal efficacy in approximately 70% of patients due to MGMT expression. LP-184 is an acylfulvene-derived prodrug activated by the oxidoreductase PTGR1 that alkylates at N3-adenine, not reported to be repaired by MGMT. This article examines LP-184 efficacy against preclinical GBM models and identifies molecular predictors of LP-184 efficacy in clinical GBM. EXPERIMENTAL DESIGN LP-184 effects on GBM cell viability and DNA damage were determined using cell lines, primary PDX-derived cells and patient-derived neurospheres. GBM cell sensitivities to LP-184 relative to temozolomide and MGMT expression were examined. Pharmacokinetics and CNS bioavailability were evaluated in mice with GBM xenografts. LP-184 effects on GBM xenograft growth and animal survival were determined. Machine learning, bioinformatic tools, and clinical databases identified molecular predictors of GBM cells and tumors to LP-184 responsiveness. RESULTS LP-184 inhibited viability of multiple GBM cell isolates including temozolomide-resistant and MGMT-expressing cells at IC50 = approximately 22-310 nmol/L. Pharmacokinetics showed favorable AUCbrain/plasma and AUCtumor/plasma ratios of 0.11 (brain Cmax = 839 nmol/L) and 0.2 (tumor Cmax = 2,530 nmol/L), respectively. LP-184 induced regression of GBM xenografts and prolonged survival of mice bearing orthotopic xenografts. Bioinformatic analyses identified PTGR1 elevation in clinical GBM subtypes and associated LP-184 sensitivity with EGFR signaling, low nucleotide excision repair (NER), and low ERCC3 expression. Spironolactone, which induces ERCC3 degradation, decreased LP-184 IC50 3 to 6 fold and enhanced GBM xenograft antitumor responses. CONCLUSIONS These results establish LP-184 as a promising chemotherapeutic for GBM with enhanced efficacy in intrinsic or spironolactone-induced TC-NER-deficient tumors.
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Affiliation(s)
- Bachchu Lal
- Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, Maryland
| | | | | | - Rana Rais
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Jesse Alt
- Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Ying Wu
- Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Hernando Lopez-Bertoni
- Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, Maryland
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Sophie Sall
- Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, Maryland
| | | | | | - Barbara S Slusher
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | | | - John Laterra
- Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, Maryland
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
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3
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Kathad U, Kulkarni A, McDermott JR, Wegner J, Carr P, Biyani N, Modali R, Richard JP, Sharma P, Bhatia K. A machine learning-based gene signature of response to the novel alkylating agent LP-184 distinguishes its potential tumor indications. BMC Bioinformatics 2021; 22:102. [PMID: 33653269 PMCID: PMC7923321 DOI: 10.1186/s12859-021-04040-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 02/15/2021] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Non-targeted cytotoxics with anticancer activity are often developed through preclinical stages using response criteria observed in cell lines and xenografts. A panel of the NCI-60 cell lines is frequently the first line to define tumor types that are optimally responsive. Open data on the gene expression of the NCI-60 cell lines, provides a unique opportunity to add another dimension to the preclinical development of such drugs by interrogating correlations with gene expression patterns. Machine learning can be used to reduce the complexity of whole genome gene expression patterns to derive manageable signatures of response. Application of machine learning in early phases of preclinical development is likely to allow a better positioning and ultimate clinical success of molecules. LP-184 is a highly potent novel alkylating agent where the preclinical development is being guided by a dedicated machine learning-derived response signature. We show the feasibility and the accuracy of such a signature of response by accurately predicting the response to LP-184 validated using wet lab derived IC50s on a panel of cell lines. RESULTS We applied our proprietary RADR® platform to an NCI-60 discovery dataset encompassing LP-184 IC50s and publicly available gene expression data. We used multiple feature selection layers followed by the XGBoost regression model and reduced the complexity of 20,000 gene expression values to generate a 16-gene signature leading to the identification of a set of predictive candidate biomarkers which form an LP-184 response gene signature. We further validated this signature and predicted response to an additional panel of cell lines. Considering fold change differences and correlation between actual and predicted LP-184 IC50 values as validation performance measures, we obtained 86% accuracy at four-fold cut-off, and a strong (r = 0.70) and significant (p value 1.36e-06) correlation between actual and predicted LP-184 sensitivity. In agreement with the perceived mechanism of action of LP-184, PTGR1 emerged as the top weighted gene. CONCLUSION Integration of a machine learning-derived signature of response with in vitro assessment of LP-184 efficacy facilitated the derivation of manageable yet robust biomarkers which can be used to predict drug sensitivity with high accuracy and clinical value.
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Affiliation(s)
- Umesh Kathad
- Lantern Pharma, Inc., 1920 McKinney Ave, 7th floor, Dallas, TX, 75201, USA.
| | - Aditya Kulkarni
- Lantern Pharma, Inc., 1920 McKinney Ave, 7th floor, Dallas, TX, 75201, USA
| | | | - Jordan Wegner
- Lantern Pharma, Inc., 1920 McKinney Ave, 7th floor, Dallas, TX, 75201, USA
| | - Peter Carr
- Lantern Pharma, Inc., 1920 McKinney Ave, 7th floor, Dallas, TX, 75201, USA
| | - Neha Biyani
- Lantern Pharma, Inc., 1920 McKinney Ave, 7th floor, Dallas, TX, 75201, USA
| | - Rama Modali
- REPROCELL USA Inc., 9000 Virginia Manor Rd, Ste 207, Beltsville, MD, 20705, USA
| | | | - Panna Sharma
- Lantern Pharma, Inc., 1920 McKinney Ave, 7th floor, Dallas, TX, 75201, USA
| | - Kishor Bhatia
- Lantern Pharma, Inc., 1920 McKinney Ave, 7th floor, Dallas, TX, 75201, USA
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4
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Dymova MA, Endutkin AV, Polunovsky VV, Zakabunin AI, Khrapov EA, Torgasheva NA, Yudkina AV, Mechetin GV, Filipenko ML, Zharkov DO. Characterization of Recombinant Endonuclease IV from Mycobacterium tuberculosis. Mol Biol 2021. [DOI: 10.1134/s0026893321020059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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5
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Mirza-Aghazadeh-Attari M, Darband SG, Kaviani M, Mihanfar A, Aghazadeh Attari J, Yousefi B, Majidinia M. DNA damage response and repair in colorectal cancer: Defects, regulation and therapeutic implications. DNA Repair (Amst) 2018; 69:34-52. [PMID: 30055507 DOI: 10.1016/j.dnarep.2018.07.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 07/15/2018] [Accepted: 07/15/2018] [Indexed: 12/11/2022]
Abstract
DNA damage response, a key factor involved in maintaining genome integrity and stability, consists of several kinase-dependent signaling pathways, which sense and transduce DNA damage signal. The severity of damage appears to determine DNA damage responses, which can include cell cycle arrest, damage repair and apoptosis. A number of recent studies have demonstrated that defection in signaling through this network is thought to be an underlying mechanism behind the development and progression of various types of human malignancies, including colorectal cancer. In this review, colorectal cancer and its molecular pathology as well as DNA damage response is briefly introduced. Finally, the involvement of key components of this network in the initiation/progression, prognosis, response to treatment and development of drug resistance is comprehensively discussed.
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Affiliation(s)
- Mohammad Mirza-Aghazadeh-Attari
- Aging Research Institute, Tabriz University of Medical Sciences, Tabriz, Iran; Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Saber Ghazizadeh Darband
- Danesh Pey Hadi Co., Health Technology Development Center, Urmia University of Medical Sciences, Urmia, Iran
| | - Mojtaba Kaviani
- School of Nutrition and Dietetics, Acadia University, Wolfville, Nova Scotia, Canada
| | - Ainaz Mihanfar
- Stem Cell and Regenerative Medicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Bahman Yousefi
- Molecular Medicine Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
| | - Maryam Majidinia
- Solid Tumor Research Center, Urmia University of Medical Sciences, Urmia, Iran.
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6
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Abstract
RNA polymerase II (Pol II) catalyzes the transcription of DNA to RNA in the nucleus. DNA alkylating cancer drugs can stall transcription; however, the basis for Pol II stalling when encountering a DNA template with minor-groove alkylation adducts has remained elusive due to its inherent chemical instability. We characterized the behavior of Pol II in transcription over minor-groove alkylation adducts and uncovered a previously unobserved mode of Pol II stalling wherein clashes between DNA adducts and the mobile trigger loop of RNA Pol II prevent translocation of the enzyme after nucleotide insertion. These results provide a molecular basis for how DNA damage in transcribed portions of the genome initiates DNA repair contributing to drug resistance. Several anticancer agents that form DNA adducts in the minor groove interfere with DNA replication and transcription to induce apoptosis. Therapeutic resistance can occur, however, when cells are proficient in the removal of drug-induced damage. Acylfulvenes are a class of experimental anticancer agents with a unique repair profile suggesting their capacity to stall RNA polymerase (Pol) II and trigger transcription-coupled nucleotide excision repair. Here we show how different forms of DNA alkylation impair transcription by RNA Pol II in cells and with the isolated enzyme and unravel a mode of RNA Pol II stalling that is due to alkylation of DNA in the minor groove. We incorporated a model for acylfulvene adducts, the stable 3-deaza-3-methoxynaphtylethyl-adenosine analog (3d-Napht-A), and smaller 3-deaza-adenosine analogs, into DNA oligonucleotides to assess RNA Pol II transcription elongation in vitro. RNA Pol II was strongly blocked by a 3d-Napht-A analog but bypassed smaller analogs. Crystal structure analysis revealed that a DNA base containing 3d-Napht-A can occupy the +1 templating position and impair closing of the trigger loop in the Pol II active center and polymerase translocation into the next template position. These results show how RNA Pol II copes with minor-groove DNA alkylation and establishes a mechanism for drug resistance.
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7
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Otto C, Spivak G, Aloisi CMN, Menigatti M, Naegeli H, Hanawalt PC, Tanasova M, Sturla SJ. Modulation of Cytotoxicity by Transcription-Coupled Nucleotide Excision Repair Is Independent of the Requirement for Bioactivation of Acylfulvene. Chem Res Toxicol 2017; 30:769-776. [PMID: 28076683 DOI: 10.1021/acs.chemrestox.6b00240] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bioactivation as well as DNA repair affects the susceptibility of cancer cells to the action of DNA-alkylating chemotherapeutic drugs. However, information is limited with regard to the relative contributions of these processes to the biological outcome of metabolically activated DNA alkylating agents. We evaluated the influence of cellular bioactivation capacity and DNA repair on cytotoxicity of the DNA alkylating agent acylfulvene (AF). We compared the cytotoxicity and RNA synthesis inhibition by AF and its synthetic activated analogue iso-M0 in a panel of fibroblast cell lines with deficiencies in transcription-coupled (TC-NER) or global genome nucleotide excision repair (GG-NER). We related these data to the inherent bioactivation capacity of each cell type on the basis of mRNA levels. We demonstrated that specific inactivation of TC-NER by siRNA had the largest positive impact on AF activity in a cancer cell line. These findings establish that transcription-coupled DNA repair reduces cellular sensitivity to AF, independent of the requirement for bioactivation.
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Affiliation(s)
- Claudia Otto
- Department of Health Sciences and Technology, ETH Zurich , 8092 Zurich, Switzerland
| | - Graciela Spivak
- Department of Biology, Stanford University , Stanford, California 94305, United States
| | - Claudia M N Aloisi
- Department of Health Sciences and Technology, ETH Zurich , 8092 Zurich, Switzerland
| | - Mirco Menigatti
- Institute of Molecular Cancer Research, University of Zurich , 8057 Zurich, Switzerland
| | - Hanspeter Naegeli
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse , 8057 Zurich, Switzerland
| | - Philip C Hanawalt
- Department of Biology, Stanford University , Stanford, California 94305, United States
| | - Marina Tanasova
- Department of Health Sciences and Technology, ETH Zurich , 8092 Zurich, Switzerland.,Department of Chemistry, Michigan Technological University , Houghton, Michigan 49932, United States
| | - Shana J Sturla
- Department of Health Sciences and Technology, ETH Zurich , 8092 Zurich, Switzerland
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8
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Stornetta A, Zimmermann M, Cimino GD, Henderson PT, Sturla SJ. DNA Adducts from Anticancer Drugs as Candidate Predictive Markers for Precision Medicine. Chem Res Toxicol 2017; 30:388-409. [PMID: 27936622 PMCID: PMC5379252 DOI: 10.1021/acs.chemrestox.6b00380] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Indexed: 01/23/2023]
Abstract
Biomarker-driven drug selection plays a central role in cancer drug discovery and development, and in diagnostic strategies to improve the use of traditional chemotherapeutic drugs. DNA-modifying anticancer drugs are still used as first line medication, but drawbacks such as resistance and side effects remain an issue. Monitoring the formation and level of DNA modifications induced by anticancer drugs is a potential strategy for stratifying patients and predicting drug efficacy. In this perspective, preclinical and clinical data concerning the relationship between drug-induced DNA adducts and biological response for platinum drugs and combination therapies, nitrogen mustards and half-mustards, hypoxia-activated drugs, reductase-activated drugs, and minor groove binding agents are presented and discussed. Aspects including measurement strategies, identification of adducts, and biological factors that influence the predictive relationship between DNA modification and biological response are addressed. A positive correlation between DNA adduct levels and response was observed for the majority of the studies, demonstrating the high potential of using DNA adducts from anticancer drugs as mechanism-based biomarkers of susceptibility, especially as bioanalysis approaches with higher sensitivity and throughput emerge.
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Affiliation(s)
- Alessia Stornetta
- Department
of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, 8092 Zurich, Switzerland
| | - Maike Zimmermann
- Department
of Internal Medicine, Division of Hematology and Oncology and the
UC Davis Comprehensive Cancer Center, University
of California Davis, 4501 X Street, Sacramento, California 95655, United States
- Accelerated
Medical Diagnostics, Inc., 2121 Second Street, B101, Davis, California 95618, United States
| | - George D. Cimino
- Accelerated
Medical Diagnostics, Inc., 2121 Second Street, B101, Davis, California 95618, United States
| | - Paul T. Henderson
- Department
of Internal Medicine, Division of Hematology and Oncology and the
UC Davis Comprehensive Cancer Center, University
of California Davis, 4501 X Street, Sacramento, California 95655, United States
- Accelerated
Medical Diagnostics, Inc., 2121 Second Street, B101, Davis, California 95618, United States
| | - Shana J. Sturla
- Department
of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, 8092 Zurich, Switzerland
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9
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Malvezzi S, Angelov T, Sturla SJ. Minor Groove 3-Deaza-Adenosine Analogues: Synthesis and Bypass in Translesion DNA Synthesis. Chemistry 2016; 23:1101-1109. [PMID: 27862447 DOI: 10.1002/chem.201604289] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Indexed: 11/07/2022]
Abstract
Anticancer drugs that alkylate DNA in the minor groove may give rise to 3-alkyl-adenosine adducts that interfere with replication, inducing apoptosis in rapidly dividing cancer cells. However, translesion DNA synthesis (TLS) by polymerase enzymes (Pols) with the capacity to bypass DNA adducts may contribute to damage tolerance and drug resistance. 3-Alkyl-adenosine adducts are unstable and depurinate, which is a barrier to addressing chemical and enzymatic aspects of how they impact the progress of DNA Pols. To characterize structure-based relationships of 3-adenine alkylation relevant to cancer drugs on duplex stability and DNA Pol-catalyzed DNA synthesis, we synthesized stable 3-deaza-3-alkyl-adenosine analogues, including 3-deaza-3-phenethyl-adenosine and 3-deaza-3-methoxynaphthylethyl-adenosine, and incorporated them into oligonucleotides. A moderate reduction of duplex stability was observed on the basis of thermal denaturation data. Replication studies using purified Y-family human DNA Pols hPol η, κ, and ι indicated that these enzymes can perform TLS over the modified bases. hPol η had higher misincorporation rates when synthesizing opposite the modified bases compared with adenine, whereas hPol κ and ι maintained high fidelity. These results provide insight into how alterations in chemical structure reduce bypass of minor-groove adducts, and provide novel chemical probes for evaluating minor-groove DNA alkylation.
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Affiliation(s)
- Stefano Malvezzi
- Department of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, 8092, Zurich, Switzerland
| | - Todor Angelov
- Department of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, 8092, Zurich, Switzerland
| | - Shana J Sturla
- Department of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, 8092, Zurich, Switzerland
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10
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Abstract
The demonstration of DNA damage excision and repair replication by Setlow, Howard-Flanders, Hanawalt and their colleagues in the early 1960s, constituted the discovery of the ubiquitous pathway of nucleotide excision repair (NER). The serial steps in NER are similar in organisms from unicellular bacteria to complex mammals and plants, and involve recognition of lesions, adducts or structures that disrupt the DNA double helix, removal of a short oligonucleotide containing the offending lesion, synthesis of a repair patch copying the opposite undamaged strand, and ligation, to restore the DNA to its original form. The transcription-coupled repair (TCR) subpathway of NER, discovered nearly two decades later, is dedicated to the removal of lesions from the template DNA strands of actively transcribed genes. In this review I will outline the essential factors and complexes involved in NER in humans, and will comment on additional factors and metabolic processes that affect the efficiency of this important process.
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Affiliation(s)
- Graciela Spivak
- Department of Biology, Stanford University, Stanford, CA 94305-5020,USA.
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