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Das D, Duncton MAJ, Georgiadis TM, Pellicena P, Clark J, Sobol RW, Georgiadis MM, King-Underwood J, Jobes DV, Chang C, Gao Y, Deacon AM, Wilson DM. A New Drug Discovery Platform: Application to DNA Polymerase Eta and Apurinic/Apyrimidinic Endonuclease 1. Int J Mol Sci 2023; 24:16637. [PMID: 38068959 PMCID: PMC10706420 DOI: 10.3390/ijms242316637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 10/26/2023] [Accepted: 10/27/2023] [Indexed: 12/18/2023] Open
Abstract
The ability to quickly discover reliable hits from screening and rapidly convert them into lead compounds, which can be verified in functional assays, is central to drug discovery. The expedited validation of novel targets and the identification of modulators to advance to preclinical studies can significantly increase drug development success. Our SaXPyTM ("SAR by X-ray Poses Quickly") platform, which is applicable to any X-ray crystallography-enabled drug target, couples the established methods of protein X-ray crystallography and fragment-based drug discovery (FBDD) with advanced computational and medicinal chemistry to deliver small molecule modulators or targeted protein degradation ligands in a short timeframe. Our approach, especially for elusive or "undruggable" targets, allows for (i) hit generation; (ii) the mapping of protein-ligand interactions; (iii) the assessment of target ligandability; (iv) the discovery of novel and potential allosteric binding sites; and (v) hit-to-lead execution. These advances inform chemical tractability and downstream biology and generate novel intellectual property. We describe here the application of SaXPy in the discovery and development of DNA damage response inhibitors against DNA polymerase eta (Pol η or POLH) and apurinic/apyrimidinic endonuclease 1 (APE1 or APEX1). Notably, our SaXPy platform allowed us to solve the first crystal structures of these proteins bound to small molecules and to discover novel binding sites for each target.
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Affiliation(s)
- Debanu Das
- XPose Therapeutics, Inc., San Carlos, CA 94070, USA
- Accelero Biostructures, Inc., San Carlos, CA 94070, USA
| | | | | | | | - Jennifer Clark
- Mitchell Cancer Institute and Department of Pharmacology, University of South Alabama, Mobile, AL 36604, USA
| | - Robert W. Sobol
- Mitchell Cancer Institute and Department of Pharmacology, University of South Alabama, Mobile, AL 36604, USA
- Department of Pathology & Laboratory Medicine, Warrant Alpert Medical School & Legorreta Cancer Center, Brown University, Providence, RI 02912, USA
| | - Millie M. Georgiadis
- XPose Therapeutics, Inc., San Carlos, CA 94070, USA
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | | | - David V. Jobes
- XPose Therapeutics, Inc., San Carlos, CA 94070, USA
- Mid-Atlantic BioTherapeutics, Inc., Doylestown, PA 18902, USA
| | - Caleb Chang
- Department of BioSciences, Rice University, Houston, TX 77251, USA
| | - Yang Gao
- Department of BioSciences, Rice University, Houston, TX 77251, USA
| | - Ashley M. Deacon
- XPose Therapeutics, Inc., San Carlos, CA 94070, USA
- Accelero Biostructures, Inc., San Carlos, CA 94070, USA
| | - David M. Wilson
- XPose Therapeutics, Inc., San Carlos, CA 94070, USA
- Biomedical Research Institute, Hasselt University, 3500 Diepenbeek, Belgium
- Belgium & Boost Scientific, 3550 Heusden-Zolder, Belgium
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2
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Siswanto FM, Okukawa K, Tamura A, Oguro A, Imaoka S. Hydrogen peroxide activates APE1/Ref-1 via NF-κB and Parkin: A role in liver cancer resistance to oxidative stress. Free Radic Res 2023:1-31. [PMID: 37364176 DOI: 10.1080/10715762.2023.2229509] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 05/09/2023] [Accepted: 06/20/2023] [Indexed: 06/28/2023]
Abstract
Cancer cells exhibit an altered redox balance and aberrant redox signaling due to genetic, metabolic, and microenvironment-associated reprogramming. Persistently elevated levels of reactive oxygen species (ROS) contribute to many aspects of tumor development and progression. Emerging studies demonstrated the vital role of apurinic/apyrimidinic endonuclease 1 or reduction/oxidation (redox) factor 1(APE1/Ref-1) in the oxidative stress response and survival of cancer cells. APE1/Ref-1 is a multifunctional enzyme involved in the DNA damage response and functions as a redox regulator of transcription factors. We herein demonstrated that basal hydrogen peroxide (H2O2) and APE1/Ref-1 expression levels were markedly higher in cancer cell lines than in non-cancerous cells. Elevated APE1/Ref-1 levels were associated with shorter survival in liver cancer patients. Mechanistically, we showed that H2O2 activated nuclear factor-κB (NF-κB). RelA/p65 inhibited the expression of the E3 ubiquitin ligase Parkin, possibly by interfering with ATF4 activity. Parkin was responsible for the ubiquitination and proteasomal degradation of APE1/Ref-1; therefore, the H2O2-induced suppression of Parkin expression increased APE1/Ref-1 levels. The probability of survival was lower in liver cancer patients with low Parkin and high RelA expression levels. Additionally, Parkin and RelA expression levels negatively and positively correlated with APE1/Ref-1 levels, respectively, in the TCGA liver cancer cohort. We concluded that increases in APE1/Ref-1 via the NF-κB and Parkin pathways are critical for cancer cell survival under oxidative stress. The present results show the potential of the NF-κB-Parkin-APE1/Ref-1 axis as a prognostic factor and therapeutic strategy to eradicate liver cancer.
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Affiliation(s)
- Ferbian Milas Siswanto
- Department of Biomedical Chemistry, School of Biological and Environmental Sciences, Kwansei Gakuin University, Sanda, Japan
- Department of Biochemistry, School of Medicine and Health Sciences, Atma Jaya Catholic University of Indonesia, Jakarta, Indonesia
| | - Kenta Okukawa
- Department of Biomedical Chemistry, School of Biological and Environmental Sciences, Kwansei Gakuin University, Sanda, Japan
| | - Akiyoshi Tamura
- Department of Biomedical Chemistry, School of Biological and Environmental Sciences, Kwansei Gakuin University, Sanda, Japan
| | - Ami Oguro
- Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Susumu Imaoka
- Department of Biomedical Chemistry, School of Biological and Environmental Sciences, Kwansei Gakuin University, Sanda, Japan
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3
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Lu P, Cao X, Zheng J, Sun Y, Tang Z, Zhao M. Visualization and Comparison of the Level of Apurinic/Apyrimidinic Endonuclease 1 in Live Normal/Cancerous and Neuron Cells with a Fluorescent Nanoprobe. Molecules 2023; 28:molecules28093935. [PMID: 37175345 PMCID: PMC10179877 DOI: 10.3390/molecules28093935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 04/24/2023] [Accepted: 05/05/2023] [Indexed: 05/15/2023] Open
Abstract
As a major apurinic/apyrimidinic endonuclease and a redox signaling protein in human cells, APE1 plays a crucial role in cellular function and survival. The relationship between alterations of APE1 expression and subcellular localization and the initiation, development and treatment of various cancers has received extensive attention. However, comparing the in-vivo activity of APE1 in normal and cancerous breast live cells remains challenging due to the low efficiency of commonly used liposome transfection methods in delivering DNA substrate probes into human normal breast epithelial cells (MCF-10A). In this work, we develop a DNA/RNA hybrid-based small magnetic fluorescent nanoprobe (25 ± 3 nm) that can be taken up by various live cells under magnetic transfection. The D0/R-nanoprobe demonstrates an outstanding specificity toward APE1 and strong resistance to the cellular background interference. Using this nanoprobe, we are not only able to visualize the intracellular activity of APE1 in breast ductal carcinoma (MCF-7) live cells, but also demonstrate the APE1 activity in MCF-10A live cells for the first time. The method is then extended to observe the changes in APE1 levels in highly metabolically active neuroendocrine cells under normal conditions and severe attacks by reactive oxygen species in real-time. The fluorescent nanoprobe provides a useful tool for studying the dynamic changes of intracellular APE1 in normal or cancerous live cells. It also displays the potential for visible and controllable release of miRNA drugs within live cells for therapeutic purposes.
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Affiliation(s)
- Peng Lu
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Xiangjian Cao
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Jinghui Zheng
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Ying Sun
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Ziyu Tang
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Meiping Zhao
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
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4
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Pidugu LS, Servius HW, Sevdalis SE, Cook ME, Varney KM, Pozharski E, Drohat AC. Characterizing inhibitors of human AP endonuclease 1. PLoS One 2023; 18:e0280526. [PMID: 36652434 PMCID: PMC9847973 DOI: 10.1371/journal.pone.0280526] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 12/30/2022] [Indexed: 01/19/2023] Open
Abstract
AP endonuclease 1 (APE1) processes DNA lesions including apurinic/apyrimidinic sites and 3´-blocking groups, mediating base excision repair and single strand break repair. Much effort has focused on developing specific inhibitors of APE1, which could have important applications in basic research and potentially lead to clinical anticancer agents. We used structural, biophysical, and biochemical methods to characterize several reported inhibitors, including 7-nitroindole-2-carboxylic acid (CRT0044876), given its small size, reported potency, and widespread use for studying APE1. Intriguingly, NMR chemical shift perturbation (CSP) experiments show that CRT0044876 and three similar indole-2-carboxylic acids bind a pocket distal from the APE1 active site. A crystal structure confirms these findings and defines the pose for 5-nitroindole-2-carboxylic acid. However, dynamic light scattering experiments show the indole compounds form colloidal aggregates that could bind (sequester) APE1, causing nonspecific inhibition. Endonuclease assays show the compounds lack significant APE1 inhibition under conditions (detergent) that disrupt aggregation. Thus, binding of the indole-2-carboxylic acids at the remote pocket does not inhibit APE1 repair activity. Myricetin also forms aggregates and lacks APE1 inhibition under aggregate-disrupting conditions. Two other reported compounds (MLS000552981, MLS000419194) inhibit APE1 in vitro with low micromolar IC50 and do not appear to aggregate in this concentration range. However, NMR CSP experiments indicate the compounds do not bind specifically to apo- or Mg2+-bound APE1, pointing to a non-specific mode of inhibition, possibly DNA binding. Our results highlight methods for rigorous interrogation of putative APE1 inhibitors and should facilitate future efforts to discover compounds that specifically inhibit this important repair enzyme.
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Affiliation(s)
- Lakshmi S. Pidugu
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Hardler W. Servius
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Spiridon E. Sevdalis
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Mary E. Cook
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Kristen M. Varney
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Edwin Pozharski
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Center for Biomolecular Therapeutics, Institute for Bioscience and Biotechnology Research, Rockville, Maryland, United States of America
- * E-mail: (EP); (ACD)
| | - Alexander C. Drohat
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * E-mail: (EP); (ACD)
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Miner KM, Jamenis AS, Bhatia TN, Clark RN, Rajasundaram D, Sauvaigo S, Mason DM, Posimo JM, Abraham N, DeMarco BA, Hu X, Stetler RA, Chen J, Sanders LH, Luk KC, Leak RK. α-synucleinopathy exerts sex-dimorphic effects on the multipurpose DNA repair/redox protein APE1 in mice and humans. Prog Neurobiol 2022; 216:102307. [PMID: 35710046 PMCID: PMC9514220 DOI: 10.1016/j.pneurobio.2022.102307] [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: 11/03/2021] [Revised: 04/05/2022] [Accepted: 06/10/2022] [Indexed: 11/16/2022]
Abstract
Lewy body disorders are characterized by oxidative damage to DNA and inclusions rich in aggregated forms of α-synuclein. Among other roles, apurinic/apyrimidinic endonuclease 1 (APE1) repairs oxidative DNA damage, and APE1 polymorphisms have been linked to cases of Lewy body disorders. However, the link between APE1 and α-synuclein is unexplored. We report that knockdown or inhibition of APE1 amplified inclusion formation in primary hippocampal cultures challenged with preformed α-synuclein fibrils. Fibril infusions into the mouse olfactory bulb/anterior olfactory nucleus (OB/AON) elicited a modest decrease in APE1 expression in the brains of male mice but an increase in females. Similarly, men with Lewy body disorders displayed lower APE1 expression in the OB and amygdala compared to women. Preformed fibril infusions of the mouse OB/AON induced more robust base excision repair of DNA lesions in females than males. No fibril-mediated loss of APE1 expression was observed in male mice when the antioxidant N-acetylcysteine was added to their diet. These findings reveal a potential sex-biased link between α-synucleinopathy and APE1 in mice and humans. Further studies are warranted to determine how this multifunctional protein modifies α-synuclein inclusions and, conversely, how α-synucleinopathy and biological sex interact to modify APE1.
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Affiliation(s)
- Kristin M Miner
- Graduate School of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, USA
| | - Anuj S Jamenis
- Graduate School of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, USA
| | - Tarun N Bhatia
- Graduate School of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, USA
| | - Rachel N Clark
- Graduate School of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, USA
| | - Dhivyaa Rajasundaram
- Department of Pediatrics, Rangos Research Center, UPMC Children's Hospital of Pittsburgh, PA 15224, USA
| | | | - Daniel M Mason
- Graduate School of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, USA
| | - Jessica M Posimo
- Graduate School of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, USA
| | - Nevil Abraham
- Graduate School of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, USA
| | - Brett A DeMarco
- Graduate School of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, USA
| | - Xiaoming Hu
- Department of Neurology, University of Pittsburgh, PA 15213, USA
| | - R Anne Stetler
- Department of Neurology, University of Pittsburgh, PA 15213, USA
| | - Jun Chen
- Department of Neurology, University of Pittsburgh, PA 15213, USA
| | - Laurie H Sanders
- Department of Neurology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Kelvin C Luk
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19147, USA
| | - Rehana K Leak
- Graduate School of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, USA.
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6
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Vickridge E, Faraco CCF, Nepveu A. Base excision repair accessory factors in senescence avoidance and resistance to treatments. CANCER DRUG RESISTANCE (ALHAMBRA, CALIF.) 2022; 5:703-720. [PMID: 36176767 PMCID: PMC9511810 DOI: 10.20517/cdr.2022.36] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 05/20/2022] [Accepted: 05/26/2022] [Indexed: 06/16/2023]
Abstract
Cancer cells, in which the RAS and PI3K pathways are activated, produce high levels of reactive oxygen species (ROS), which cause oxidative DNA damage and ultimately cellular senescence. This process has been documented in tissue culture, mouse models, and human pre-cancerous lesions. In this context, cellular senescence functions as a tumour suppressor mechanism. Some rare cancer cells, however, manage to adapt to avoid senescence and continue to proliferate. One well-documented mode of adaptation involves increased production of antioxidants often associated with inactivation of the KEAP1 tumour suppressor gene and the resulting upregulation of the NRF2 transcription factor. In this review, we detail an alternative mode of adaptation to oxidative DNA damage induced by ROS: the increased activity of the base excision repair (BER) pathway, achieved through the enhanced expression of BER enzymes and DNA repair accessory factors. These proteins, exemplified here by the CUT domain proteins CUX1, CUX2, and SATB1, stimulate the activity of BER enzymes. The ensued accelerated repair of oxidative DNA damage enables cancer cells to avoid senescence despite high ROS levels. As a by-product of this adaptation, these cancer cells exhibit increased resistance to genotoxic treatments including ionizing radiation, temozolomide, and cisplatin. Moreover, considering the intrinsic error rate associated with DNA repair and translesion synthesis, the elevated number of oxidative DNA lesions caused by high ROS leads to the accumulation of mutations in the cancer cell population, thereby contributing to tumour heterogeneity and eventually to the acquisition of resistance, a major obstacle to clinical treatment.
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Affiliation(s)
- Elise Vickridge
- Goodman Cancer Institute, McGill University, 1160 Pine avenue West, Montreal, Québec H3A 1A3, Canada
- These authors contributed equally to this work
| | - Camila C. F. Faraco
- Goodman Cancer Institute, McGill University, 1160 Pine avenue West, Montreal, Québec H3A 1A3, Canada
- Departments of Biochemistry, McGill University, 1160 Pine avenue West, Montreal, Québec H3A 1A3, Canada
- These authors contributed equally to this work
| | - Alain Nepveu
- Goodman Cancer Institute, McGill University, 1160 Pine avenue West, Montreal, Québec H3A 1A3, Canada
- Departments of Biochemistry, McGill University, 1160 Pine avenue West, Montreal, Québec H3A 1A3, Canada
- Medicine, McGill University, 1160 Pine avenue West, Montreal, Québec H3A 1A3, Canada
- Oncology, McGill University, 1160 Pine avenue West, Montreal, Québec H3A 1A3, Canada
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7
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McSwain LF, Parwani KK, Shahab SW, Hambardzumyan D, MacDonald TJ, Spangle JM, Kenney AM. Medulloblastoma and the DNA Damage Response. Front Oncol 2022; 12:903830. [PMID: 35747808 PMCID: PMC9209741 DOI: 10.3389/fonc.2022.903830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 05/10/2022] [Indexed: 12/04/2022] Open
Abstract
Medulloblastoma (MB) is the most common malignant brain tumor in children with standard of care consisting of surgery, radiation, and chemotherapy. Recent molecular profiling led to the identification of four molecularly distinct MB subgroups – Wingless (WNT), Sonic Hedgehog (SHH), Group 3, and Group 4. Despite genomic MB characterization and subsequent tumor stratification, clinical treatment paradigms are still largely driven by histology, degree of surgical resection, and presence or absence of metastasis rather than molecular profile. Patients usually undergo resection of their tumor followed by craniospinal radiation (CSI) and a 6 month to one-year multi-agent chemotherapeutic regimen. While there is clearly a need for development of targeted agents specific to the molecular alterations of each patient, targeting proteins responsible for DNA damage repair could have a broader impact regardless of molecular subgrouping. DNA damage response (DDR) protein inhibitors have recently emerged as targeted agents with potent activity as monotherapy or in combination in different cancers. Here we discuss the molecular underpinnings of genomic instability in MB and potential avenues for exploitation through DNA damage response inhibition.
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Affiliation(s)
- Leon F. McSwain
- Department of Pediatrics, Emory University, Atlanta, GA, United States
| | - Kiran K. Parwani
- Winship Cancer Institute, Emory University, Atlanta, GA, United States
- Department of Radiation Oncology, Emory University, Atlanta, GA, United States
| | - Shubin W. Shahab
- Winship Cancer Institute, Emory University, Atlanta, GA, United States
| | - Dolores Hambardzumyan
- Departments of Neurosurgery and Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Tobey J. MacDonald
- Department of Pediatrics, Emory University, Atlanta, GA, United States
- Winship Cancer Institute, Emory University, Atlanta, GA, United States
| | - Jennifer M. Spangle
- Winship Cancer Institute, Emory University, Atlanta, GA, United States
- Department of Radiation Oncology, Emory University, Atlanta, GA, United States
| | - Anna Marie Kenney
- Department of Pediatrics, Emory University, Atlanta, GA, United States
- *Correspondence: Anna Marie Kenney,
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8
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Label-free and highly sensitive APE1 detection based on rolling circle amplification combined with G-quadruplex. Talanta 2022; 244:123404. [PMID: 35349840 DOI: 10.1016/j.talanta.2022.123404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 03/12/2022] [Accepted: 03/22/2022] [Indexed: 12/13/2022]
Abstract
The highly sensitive detection of low-abundant apurinic/apyrimidinic endonuclease 1 (APE1) activity is of great significance for early diagnosis of disease and pathological research. Many methods for detecting APE1 based on isothermal nucleic acids amplification have been developed for improving its sensitivity. However, some of these methods have certain limitations, such as multiple reaction steps, narrow linear range, and complicated processes for fluorescent labeling. Herein, we develop a highly sensitive and label-free APE1 fluorescence detection method based on rolling circle amplification combined with G-quadruplex (RCA-G4). A hairpin probe (HP) labeled with the AP site can be recognized and cleaved by APE1, leading to the release of the primer sequence, which triggered RCA to produce long chain amplification products with a great amount of repeated sequences. The formed amplicon contains a series G-quadruplex structure, which can be combined with Thioflavin T (ThT) to produce fluorescence and achieve high sensitivity label-free detection of APE1. Benefit from the high amplification efficiency of RCA and the high fluorescence quantum yield of G-quadruplex/ThT, a detection limit as low as 1.52 × 10-6 U/mL and the linear range from 2 × 10-6 to 10 U/mL were obtained. The developed RCA-G4 method can be successfully used to detect APE1 in serum samples with a recovery from 96.3% to 105.7%. We believe that this approach is expected to play an important role in APE1-related disease research and drug development.
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Ray S, Chaturvedi NK, Bhakat KK, Rizzino A, Mahapatra S. Subgroup-Specific Diagnostic, Prognostic, and Predictive Markers Influencing Pediatric Medulloblastoma Treatment. Diagnostics (Basel) 2021; 12:diagnostics12010061. [PMID: 35054230 PMCID: PMC8774967 DOI: 10.3390/diagnostics12010061] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 12/11/2021] [Accepted: 12/18/2021] [Indexed: 12/24/2022] Open
Abstract
Medulloblastoma (MB) is the most common malignant central nervous system tumor in pediatric patients. Mainstay of therapy remains surgical resection followed by craniospinal radiation and chemotherapy, although limitations to this therapy are applied in the youngest patients. Clinically, tumors are divided into average and high-risk status on the basis of age, metastasis at diagnosis, and extent of surgical resection. However, technological advances in high-throughput screening have facilitated the analysis of large transcriptomic datasets that have been used to generate the current classification system, dividing patients into four primary subgroups, i.e., WNT (wingless), SHH (sonic hedgehog), and the non-SHH/WNT subgroups 3 and 4. Each subgroup can further be subdivided on the basis of a combination of cytogenetic and epigenetic events, some in distinct signaling pathways, that activate specific phenotypes impacting patient prognosis. Here, we delve deeper into the genetic basis for each subgroup by reviewing the extent of cytogenetic events in key genes that trigger neoplastic transformation or that exhibit oncogenic properties. Each of these discussions is further centered on how these genetic aberrations can be exploited to generate novel targeted therapeutics for each subgroup along with a discussion on challenges that are currently faced in generating said therapies. Our future hope is that through better understanding of subgroup-specific cytogenetic events, the field may improve diagnosis, prognosis, and treatment to improve overall quality of life for these patients.
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Affiliation(s)
- Sutapa Ray
- Department of Pediatrics, University of Nebraska Medical Center, 601 S Saddle Creek Road, Omaha, NE 68198, USA; (S.R.); (N.K.C.)
- Fred and Pamela Buffet Cancer Center, University of Nebraska Medical Center, Omaha, NE 68105, USA; (K.K.B.); (A.R.)
| | - Nagendra K. Chaturvedi
- Department of Pediatrics, University of Nebraska Medical Center, 601 S Saddle Creek Road, Omaha, NE 68198, USA; (S.R.); (N.K.C.)
- Fred and Pamela Buffet Cancer Center, University of Nebraska Medical Center, Omaha, NE 68105, USA; (K.K.B.); (A.R.)
| | - Kishor K. Bhakat
- Fred and Pamela Buffet Cancer Center, University of Nebraska Medical Center, Omaha, NE 68105, USA; (K.K.B.); (A.R.)
- Department of Genetics, Cell Biology, and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Angie Rizzino
- Fred and Pamela Buffet Cancer Center, University of Nebraska Medical Center, Omaha, NE 68105, USA; (K.K.B.); (A.R.)
- Eppley Institute for Research in Cancer and Allied Disease, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Sidharth Mahapatra
- Department of Pediatrics, University of Nebraska Medical Center, 601 S Saddle Creek Road, Omaha, NE 68198, USA; (S.R.); (N.K.C.)
- Fred and Pamela Buffet Cancer Center, University of Nebraska Medical Center, Omaha, NE 68105, USA; (K.K.B.); (A.R.)
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Correspondence: ; Tel.: +1-(402)-599-7754
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Oliveira TT, Fontes-Dantas FL, de Medeiros Oliveira RK, Pinheiro DML, Coutinho LG, da Silva VL, de Souza SJ, Agnez-Lima LF. Chemical Inhibition of Apurinic-Apyrimidinic Endonuclease 1 Redox and DNA Repair Functions Affects the Inflammatory Response via Different but Overlapping Mechanisms. Front Cell Dev Biol 2021; 9:731588. [PMID: 34616737 PMCID: PMC8488223 DOI: 10.3389/fcell.2021.731588] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Accepted: 08/27/2021] [Indexed: 01/21/2023] Open
Abstract
The presence of oxidized DNA lesions, such as 7,8-dihydro-8-oxoguanine (8-oxoG) and apurinic/apyrimidinic sites (AP sites), has been described as epigenetic signals that are involved in gene expression control. In mammals, Apurinic-apyrimidinic endonuclease 1/Redox factor-1 (APE1/Ref-1) is the main AP endonuclease of the base excision repair (BER) pathway and is involved in active demethylation processes. In addition, APE1/Ref-1, through its redox function, regulates several transcriptional factors. However, the transcriptional control targets of each APE1 function are not completely known. In this study, a transcriptomic approach was used to investigate the effects of chemical inhibition of APE1/Ref-1 redox or DNA repair functions by E3330 or methoxyamine (MX) in an inflammatory cellular model. Under lipopolysaccharide (LPS) stimulation, both E3330 and MX reduced the expression of some cytokines and chemokines. Interestingly, E3330 treatment reduced cell viability after 48 h of the treatment. Genes related to inflammatory response and mitochondrial processes were downregulated in both treatments. In the E3330 treatment, RNA processing and ribosome biogenesis genes were downregulated, while they were upregulated in the MX treatment. Furthermore, in the E3330 treatment, the cellular stress response was the main upregulated process, while the cellular macromolecule metabolic process was observed in MX-upregulated genes. Nuclear respiratory factor 1 (NRF1) was predicted to be a master regulator of the downregulated genes in both treatments, while the ETS transcription factor ELK1 (ELK1) was predicted to be a master regulator only for E3330 treatment. Decreased expression of ELK1 and its target genes and a reduced 28S/18S ratio were observed, suggesting impaired rRNA processing. In addition, both redox and repair functions can affect the expression of NRF1 and GABPA target genes. The master regulators predicted for upregulated genes were YY1 and FLI1 for the E3330 and MX treatments, respectively. In summary, the chemical inhibition of APE1/Ref-1 affects gene expression regulated mainly by transcriptional factors of the ETS family, showing partial overlap of APE1 redox and DNA repair functions, suggesting that these activities are not entirely independent. This work provides a new perspective on the interaction between APE1 redox and DNA repair activity in inflammatory response modulation and transcription.
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Affiliation(s)
- Thais Teixeira Oliveira
- Departamento de Biologia Celular e Genética, Universidade Federal do Rio Grande do Norte, UFRN, Natal, Brazil
| | - Fabrícia Lima Fontes-Dantas
- Departamento de Biologia Celular e Genética, Universidade Federal do Rio Grande do Norte, UFRN, Natal, Brazil
| | | | | | - Leonam Gomes Coutinho
- Departamento de Biologia Celular e Genética, Universidade Federal do Rio Grande do Norte, UFRN, Natal, Brazil.,Instituto Federal de Educação Tecnológica do Rio Grande do Norte, IFRN, São Paulo do Potengi, Brazil
| | - Vandeclecio Lira da Silva
- Instituto do Cérebro, Universidade Federal do Rio Grande do Norte, Natal, Brazil.,Bioinformatics Multidisciplinary Environment (BioME), IMD, Universidade Federal do Rio Grande do Norte, Natal, Brazil
| | - Sandro José de Souza
- Instituto do Cérebro, Universidade Federal do Rio Grande do Norte, Natal, Brazil.,Bioinformatics Multidisciplinary Environment (BioME), IMD, Universidade Federal do Rio Grande do Norte, Natal, Brazil
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11
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Wilson DM, Deacon AM, Duncton MAJ, Pellicena P, Georgiadis MM, Yeh AP, Arvai AS, Moiani D, Tainer JA, Das D. Fragment- and structure-based drug discovery for developing therapeutic agents targeting the DNA Damage Response. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2021; 163:130-142. [PMID: 33115610 PMCID: PMC8666131 DOI: 10.1016/j.pbiomolbio.2020.10.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 10/13/2020] [Accepted: 10/23/2020] [Indexed: 12/12/2022]
Abstract
Cancer will directly affect the lives of over one-third of the population. The DNA Damage Response (DDR) is an intricate system involving damage recognition, cell cycle regulation, DNA repair, and ultimately cell fate determination, playing a central role in cancer etiology and therapy. Two primary therapeutic approaches involving DDR targeting include: combinatorial treatments employing anticancer genotoxic agents; and synthetic lethality, exploiting a sporadic DDR defect as a mechanism for cancer-specific therapy. Whereas, many DDR proteins have proven "undruggable", Fragment- and Structure-Based Drug Discovery (FBDD, SBDD) have advanced therapeutic agent identification and development. FBDD has led to 4 (with ∼50 more drugs under preclinical and clinical development), while SBDD is estimated to have contributed to the development of >200, FDA-approved medicines. Protein X-ray crystallography-based fragment library screening, especially for elusive or "undruggable" targets, allows for simultaneous generation of hits plus details of protein-ligand interactions and binding sites (orthosteric or allosteric) that inform chemical tractability, downstream biology, and intellectual property. Using a novel high-throughput crystallography-based fragment library screening platform, we screened five diverse proteins, yielding hit rates of ∼2-8% and crystal structures from ∼1.8 to 3.2 Å. We consider current FBDD/SBDD methods and some exemplary results of efforts to design inhibitors against the DDR nucleases meiotic recombination 11 (MRE11, a.k.a., MRE11A), apurinic/apyrimidinic endonuclease 1 (APE1, a.k.a., APEX1), and flap endonuclease 1 (FEN1).
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Affiliation(s)
- David M Wilson
- Hasselt University, Biomedical Research Institute, Diepenbeek, Belgium; Boost Scientific, Heusden-Zolder, Belgium; XPose Therapeutics Inc., San Carlos, CA, USA
| | - Ashley M Deacon
- Accelero Biostructures Inc., San Francisco, CA, USA; XPose Therapeutics Inc., San Carlos, CA, USA
| | | | | | - Millie M Georgiadis
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, USA; XPose Therapeutics Inc., San Carlos, CA, USA
| | - Andrew P Yeh
- Accelero Biostructures Inc., San Francisco, CA, USA
| | - Andrew S Arvai
- Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Davide Moiani
- Department of Cancer Biology, MD Anderson Cancer Center, Houston, TX, USA; Department of Molecular and Cellular Oncology, MD Anderson Cancer Center, Houston, TX, USA
| | - John A Tainer
- Department of Cancer Biology, MD Anderson Cancer Center, Houston, TX, USA; Department of Molecular and Cellular Oncology, MD Anderson Cancer Center, Houston, TX, USA
| | - Debanu Das
- Accelero Biostructures Inc., San Francisco, CA, USA; XPose Therapeutics Inc., San Carlos, CA, USA.
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12
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Histone chaperone FACT complex inhibitor CBL0137 interferes with DNA damage repair and enhances sensitivity of medulloblastoma to chemotherapy and radiation. Cancer Lett 2021; 520:201-212. [PMID: 34271103 DOI: 10.1016/j.canlet.2021.07.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 06/24/2021] [Accepted: 07/09/2021] [Indexed: 11/21/2022]
Abstract
Medulloblastoma (MB) is a malignant pediatric brain tumor with a poor prognosis. Post-surgical radiation and cisplatin-based chemotherapy have been a mainstay of treatment, which often leads to substantial neurocognitive impairments and morbidity, highlighting the need for a novel therapeutic target to enhance the sensitivity of MB tumors to cytotoxic therapies. We performed a comprehensive study using a cohort of 71 MB patients' samples and pediatric MB cell lines and found that MB tumors have elevated levels of nucleosome remodeling FACT (FAcilitates Chromatin Transcription) complex and DNA repair enzyme AP-endonuclease1 (APE1). FACT interacts with APE1 and facilitates recruitment and acetylation of APE1 to promote repair of radiation and cisplatin-induced DNA damage. Further, levels of FACT and acetylated APE1 both are correlate strongly with MB patients' survival. Targeting FACT complex with CBL0137 inhibits DNA repair and alters expression of a subset of genes, and significantly improves the potency of cisplatin and radiation in vitro and in MB xenograft. Notably, combination of CBL0137 and cisplatin significantly suppressed MB tumor growth in an intracranial orthotopic xenograft model. We conclude that FACT complex promotes chemo-radiation resistance in MB, and FACT inhibitor CBL0137 can be used as a chemo-radiation sensitizer to augment treatment efficacy and reduce therapy-related toxicity in high-risk pediatric patients.
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13
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Silva MDO, de Sousa GR, Simões SC, Nicolucci P, Tamashiro E, Saggioro F, de Oliveira RS, Brassesco MS. Perillyl alcohol for pediatric TP53- and RAS-mutated SHH-medulloblastoma: an in vitro and in vivo translational pre-clinical study. Childs Nerv Syst 2021; 37:2163-2175. [PMID: 33885911 DOI: 10.1007/s00381-021-05115-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 03/03/2021] [Indexed: 11/30/2022]
Abstract
PURPOSE Inhalation of perillyl alcohol (POH) recently emerged as an investigational promising antiglioma strategy. However, little attention has been paid to its therapeutic potential for other brain tumors, especially in the pediatric setting. METHODS The effects of POH were explored in medulloblastoma cell models belonging to the SHH variant with activation of RAS (ONS-76) or with TP53 mutations (DAOY and UW402), by means of proliferation and invasion assays. Interactions with methotrexate, thiotepa, or ionizing radiation were also assessed. Mice bearing subcutaneous tumors were treated with intraperitoneal injections. Alternatively, animals with intracranial tumors were exposed to intranasal POH alone or combined with radiation. Tumor growth was measured by bioluminescence. Analyses of cytotoxicity to the nasal cavity were also performed, and the presence of POH in the brain, lungs, and plasma was surveyed through chromatography/mass spectrometry. RESULTS POH decreased cell proliferation and colony formation, with conspicuous death, though the invasive capacity was only affected in the NRAS-mutated cell line. Median-drug effect analysis displayed synergistic combinations with methotrexate. Otherwise, POH showed to be a reasonable radiosensitizer. In vivo, intraperitoneal injection significantly decreased tumor volume. However, its inhalation did not affect orthotopic tumors, neither alone or followed by cranial irradiation. Nasal cavity epithelium showed unimportant alterations, though, no traces of POH or its metabolites were detected in tissue samples. CONCLUSION POH presents robust in vitro antimedulloblastoma effects and sensitizes cell lines to other conventional therapeutics, reducing tumor volume when administered intraperitoneally. Nevertheless, further improvement of delivery devices and/or drug formulations are needed to better characterize its effectiveness through inhalation.
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Affiliation(s)
| | | | | | - Patrícia Nicolucci
- Physics Department from the Faculty of Philosophy, Sciences and Letters at Ribeirao Preto, University of Sao Paulo, Sao Paulo, Brazil
| | - Edwin Tamashiro
- Ribeirão Preto School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Fabiano Saggioro
- Ribeirão Preto School of Medicine, University of São Paulo, São Paulo, Brazil
| | | | - María Sol Brassesco
- Laboratory of Cell Biology and Oncogenetics, Department of Biology, Faculty of Philosophy, Sciences and Letters at Ribeirão Preto, University of São Paulo, Av. Bandeirantes, 3900, Bairro Monte Alegre, Ribeirão Preto, São Paulo, CEP 14040-900, Brazil.
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14
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Significance of base excision repair to human health. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 364:163-193. [PMID: 34507783 DOI: 10.1016/bs.ircmb.2021.05.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Oxidative and alkylating DNA damage occurs under normal physiological conditions and exogenous exposure to DNA damaging agents. To counteract DNA base damage, cells have evolved several defense mechanisms that act at different levels to prevent or repair DNA base damage. Cells combat genomic lesions like these including base modifications, abasic sites, as well as single-strand breaks, via the base excision repair (BER) pathway. In general, the core BER process involves well-coordinated five-step reactions to correct DNA base damage. In this review, we will uncover the current understanding of BER mechanisms to maintain genomic stability and the biological consequences of its failure due to repair gene mutations. The malfunction of BER can often lead to BER intermediate accumulation, which is genotoxic and can lead to different types of human disease. Finally, we will address the use of BER intermediates for targeted cancer therapy.
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15
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Long K, Gu L, Li L, Zhang Z, Li E, Zhang Y, He L, Pan F, Guo Z, Hu Z. Small-molecule inhibition of APE1 induces apoptosis, pyroptosis, and necroptosis in non-small cell lung cancer. Cell Death Dis 2021; 12:503. [PMID: 34006852 PMCID: PMC8131371 DOI: 10.1038/s41419-021-03804-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 05/05/2021] [Accepted: 05/06/2021] [Indexed: 02/07/2023]
Abstract
Apurinic/apyrimidinic endonuclease 1 (APE1) plays a critical role in the base excision repair (BER) pathway, which is responsible for the excision of apurinic sites (AP sites). In non-small cell lung cancer (NSCLC), APE1 is highly expressed and associated with poor patient prognosis. The suppression of APE1 could lead to the accumulation of unrepaired DNA damage in cells. Therefore, APE1 is viewed as an important marker of malignant tumors and could serve as a potent target for the development of antitumor drugs. In this study, we performed a high-throughput virtual screening of a small-molecule library using the three-dimensional structure of APE1 protein. Using the AP site cleavage assay and a cell survival assay, we identified a small molecular compound, NO.0449-0145, to act as an APE1 inhibitor. Treatment with NO.0449-0145 induced DNA damage, apoptosis, pyroptosis, and necroptosis in the NSCLC cell lines A549 and NCI-H460. This inhibitor was also able to impede cancer progression in an NCI-H460 mouse model. Moreover, NO.0449-0145 overcame both cisplatin- and erlotinib-resistance in NSCLC cell lines. These findings underscore the importance of APE1 as a therapeutic target in NSCLC and offer a paradigm for the development of small-molecule drugs that target key DNA repair proteins for the treatment of NSCLC and other cancers.
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Affiliation(s)
- Kaili Long
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, 210023, Nanjing, China
| | - Lili Gu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, 210023, Nanjing, China
| | - Lulu Li
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, 210023, Nanjing, China
| | - Ziyu Zhang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, 210023, Nanjing, China
| | - Enjie Li
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, 210023, Nanjing, China
| | - Yilan Zhang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, 210023, Nanjing, China
| | - Lingfeng He
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, 210023, Nanjing, China
| | - Feiyan Pan
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, 210023, Nanjing, China
| | - Zhigang Guo
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, 210023, Nanjing, China.
| | - Zhigang Hu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, 210023, Nanjing, China.
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16
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Li L, Kumar AK, Hu Z, Guo Z. Small Molecule Inhibitors Targeting Key Proteins in the DNA Damage Response for Cancer Therapy. Curr Med Chem 2021; 28:963-985. [PMID: 32091326 DOI: 10.2174/0929867327666200224102309] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 01/17/2020] [Accepted: 01/29/2020] [Indexed: 11/22/2022]
Abstract
DNA damage response (DDR) is a complicated interactional pathway. Defects that occur in subordinate pathways of the DDR pathway can lead to genomic instability and cancer susceptibility. Abnormal expression of some proteins in DDR, especially in the DNA repair pathway, are associated with the subsistence and resistance of cancer cells. Therefore, the development of small molecule inhibitors targeting the chief proteins in the DDR pathway is an effective strategy for cancer therapy. In this review, we summarize the development of small molecule inhibitors targeting chief proteins in the DDR pathway, particularly focusing on their implications for cancer therapy. We present the action mode of DDR molecule inhibitors in preclinical studies and clinical cancer therapy, including monotherapy and combination therapy with chemotherapeutic drugs or checkpoint suppression therapy.
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Affiliation(s)
- Lulu Li
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, Nanjing 210023, China
| | - Alagamuthu Karthick Kumar
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, Nanjing 210023, China
| | - Zhigang Hu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, Nanjing 210023, China
| | - Zhigang Guo
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, 1 WenYuan Road, Nanjing 210023, China
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17
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Peng Y, Pei H. DNA alkylation lesion repair: outcomes and implications in cancer chemotherapy. J Zhejiang Univ Sci B 2021; 22:47-62. [PMID: 33448187 DOI: 10.1631/jzus.b2000344] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Alkylated DNA lesions, induced by both exogenous chemical agents and endogenous metabolites, represent a major form of DNA damage in cells. The repair of alkylation damage is critical in all cells because such damage is cytotoxic and potentially mutagenic. Alkylation chemotherapy is a major therapeutic modality for many tumors, underscoring the importance of the repair pathways in cancer cells. Several different pathways exist for alkylation repair, including base excision and nucleotide excision repair, direct reversal by methyl-guanine methyltransferase (MGMT), and dealkylation by the AlkB homolog (ALKBH) protein family. However, maintaining a proper balance between these pathways is crucial for the favorable response of an organism to alkylating agents. Here, we summarize the progress in the field of DNA alkylation lesion repair and describe the implications for cancer chemotherapy.
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Affiliation(s)
- Yihan Peng
- Department of Biochemistry and Molecular Medicine, the George Washington University School of Medicine and Health Sciences, Washington, DC 20037, USA.,GW Cancer Center, the George Washington University School of Medicine and Health Sciences, Washington, DC 20052, USA
| | - Huadong Pei
- Department of Biochemistry and Molecular Medicine, the George Washington University School of Medicine and Health Sciences, Washington, DC 20037, USA. .,GW Cancer Center, the George Washington University School of Medicine and Health Sciences, Washington, DC 20052, USA.
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18
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Association between apurinic/apyrimidinic endonuclease 1 rs1760944 T>G polymorphism and susceptibility of cancer: a meta-analysis involving 21764 subjects. Biosci Rep 2020; 39:221420. [PMID: 31804681 PMCID: PMC6923335 DOI: 10.1042/bsr20190866] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Revised: 10/03/2019] [Accepted: 12/04/2019] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Previous case-control studies have suggested that apurinic/apyrimidinic endonuclease 1 (APE1) rs1760944 T>G polymorphism may be associated with cancer risk. Here, we carried out an updated meta-analysis to focus on the correlation between APE1 rs1760944 T>G locus and the risk of cancer. METHODS We used the crude odds ratios (ORs) with their 95% confidence intervals (CIs) to evaluate the possible relationship between the APE1 rs1760944 T>G polymorphism and cancer risk. Heterogeneity, publication bias and sensitivity analysis were also harnessed to check the potential bias of the present study. RESULTS Twenty-three independent studies involving 10166 cancer cases and 11598 controls were eligible for this pooled analysis. We found that APE1 rs1760944 T>G polymorphism decreased the risk of cancer in four genetic models (G vs. T: OR, 0.87; 95% CI, 0.83-0.92; P<0.001; GG vs. TT: OR, 0.77; 95% CI, 0.69-0.86; P<0.001; GG/TG vs. TT: OR, 0.83; 95% CI, 0.77-0.89, P<0.001 and GG vs. TT/TG: OR, 0.85; 95% CI, 0.80-0.92, P<0.001). Results of subgroup analyses also demonstrated that this single-nucleotide polymorphism (SNP) modified the risk among lung cancer, breast cancer, osteosarcoma, and Asians. Evidence of publication bias was found in the present study. When we treated the publication bias with 'trim-and-fill' method, the adjusted ORs and CIs were not significantly changed. CONCLUSION In conclusion, current evidence highlights that the APE1 rs1760944 T>G polymorphism is a protective factor for cancer susceptibility. In the future, case-control studies with detailed risk factors are needed to confirm or refute our findings.
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19
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Non-muscle invasive bladder cancer tissues have increased base excision repair capacity. Sci Rep 2020; 10:16371. [PMID: 33004944 PMCID: PMC7529820 DOI: 10.1038/s41598-020-73370-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 09/15/2020] [Indexed: 12/26/2022] Open
Abstract
The molecular mechanisms underlying the development and progression of bladder cancer (BC) are complex and have not been fully elucidated. Alterations in base excision repair (BER) capacity, one of several DNA repair mechanisms assigned to preserving genome integrity, have been reported to influence cancer susceptibility, recurrence, and progression, as well as responses to chemotherapy and radiotherapy. We report herein that non-muscle invasive BC (NMIBC) tissues exhibit increased uracil incision, abasic endonuclease and gap-filling activities, as well as total BER capacity in comparison to normal bladder tissue from the same patient (p < 0.05). No significant difference was detected in 8-oxoG incision activity between cancer and normal tissues. NMIBC tissues have elevated protein levels of uracil DNA glycosylase, 8-oxoguanine DNA glycosylase, AP endonuclease 1 and DNA polymerase β protein. Moreover, the fold increase in total BER and the individual BER enzyme activities were greater in high-grade tissues than in low-grade NMIBC tissues. These findings suggest that enhanced BER activity may play a role in the etiology of NMIBC and that BER proteins could serve as biomarkers in disease prognosis, progression or response to genotoxic therapeutics, such as Bacillus Calmette–Guérin.
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20
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Zhang H, Ba S, Yang Z, Wang T, Lee JY, Li T, Shao F. Graphene Quantum Dot-Based Nanocomposites for Diagnosing Cancer Biomarker APE1 in Living Cells. ACS APPLIED MATERIALS & INTERFACES 2020; 12:13634-13643. [PMID: 32129072 DOI: 10.1021/acsami.9b21385] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
As an essential DNA repair enzyme, apurinic/apyrimidinic endonuclease 1 (APE1) is overexpressed in most human cancers and is identified as a cancer diagnostic and predictive biomarker for cancer risk assessment, diagnosis, prognosis, and prediction of treatment efficacy. Despite its importance in cancer, however, it is still a significant challenge nowadays to sense abundance variation and monitor enzymatic activity of this biomarker in living cells. Here, we report our construction of biocompatible functional nanocomposites, which are a combination of meticulously designed unimolecular DNA and fine-sized graphene quantum dots. Upon utilization of these nanocomposites as diagnostic probes, massive accumulation of fluorescence signal in living cells can be triggered by merely a small amount of cellular APE1 through repeated cycles of enzymatic catalysis. Most critically, our delicate structural designs assure that these graphene quantum dot-based nanocomposites are capable of sensing cancer biomarker APE1 in identical type of cells under different cell conditions and can be applied to multiple cancerous cells in a highly sensitive and specific manners. This work not only brings about new methods for cytology-based cancer screening but also lays down a general principle for fabricating diagnostic probes that target other endogenous biomarkers in living cells.
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Affiliation(s)
- Hao Zhang
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Sai Ba
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Zhaoqi Yang
- School of Pharmaceutical Sciences, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Tianxiang Wang
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Jasmine Yiqin Lee
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Tianhu Li
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Fangwei Shao
- ZJU-UIUC Institute, Zhejiang University, Haining, Zhejiang 314400, China
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21
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Kaur S, Ramdzan ZM, Guiot MC, Li L, Leduy L, Ramotar D, Sabri S, Abdulkarim B, Nepveu A. CUX1 stimulates APE1 enzymatic activity and increases the resistance of glioblastoma cells to the mono-alkylating agent temozolomide. Neuro Oncol 2019; 20:484-493. [PMID: 29036362 DOI: 10.1093/neuonc/nox178] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Background Cut Like homeobox 1 (CUX1), which encodes an auxiliary factor in base excision repair, resides on 7q22.1, the most frequently and highly amplified chromosomal region in glioblastomas. The resistance of glioblastoma cells to the mono-alkylating agent temozolomide is determined to some extent by the activity of apurinic/apyrimidinic endonuclease 1 (APE1). Methods To monitor the effect of CUX1 and its CUT domains on APE1 activity, DNA repair assays were performed with purified proteins and cell extracts. CUX1 protein expression was analyzed by immunohistochemistry using a tumor microarray of 150 glioblastoma samples. The effect of CUX1 knockdown and overexpression on the resistance of glioblastoma cell lines to temozolomide was investigated. Results We show that CUT domains stimulate APE1 activity. In agreement with these findings, CUX1 knockdown causes an increase in the number of abasic sites in genomic DNA and a decrease in APE1 activity as measured in cell extracts. Conversely, ectopic CUX1 expression increases APE1 activity and lowers the number of abasic sites. Having established that CUX1 is expressed at high levels in most glioblastomas, we next show that the resistance of glioblastoma cells to temozolomide and to a combined treatment of temozolomide and ionizing radiation is reduced following CUX1 knockdown, but increased by overexpression of CUX1 or a short protein containing only 2 CUT domains, which is active in DNA repair but devoid of transcriptional activity. Conclusion These findings indicate that CUX1 expression level impacts on the response of glioblastoma cells to treatment and identifies the CUT domains as potential therapeutic targets.
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Affiliation(s)
- Simran Kaur
- Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada.,Departments of Biochemistry, McGill University, Montreal, Quebec, Canada
| | - Zubaidah M Ramdzan
- Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada
| | - Marie-Christine Guiot
- Pathology, McGill University, Montreal, Quebec, Canada.,Departments of Pathology, Neurology, and Neurosurgery, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada
| | - Li Li
- Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada
| | - Lam Leduy
- Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada
| | - Dindial Ramotar
- Maisonneuve-Rosemont Hospital, Research Center, Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada
| | - Siham Sabri
- Oncology, McGill University, Montreal, Quebec, Canada
| | | | - Alain Nepveu
- Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada.,Departments of Biochemistry, McGill University, Montreal, Quebec, Canada.,Oncology, McGill University, Montreal, Quebec, Canada
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22
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Abstract
Before a deleterious DNA lesion can be replaced with its undamaged counterpart, the lesion must first be removed from the genome. This process of removing and replacing DNA lesions is accomplished by the careful coordination of several protein factors during DNA repair. One such factor is the multifunctional enzyme human apurinic/apyrimidinic endonuclease 1 (APE1), known best for its DNA backbone cleavage activity at AP sites during base excision repair (BER). APE1 preforms AP site incision with surgical precision and skill, by sculpting the DNA to place the cleavage site in an optimal position for nucleophilic attack within its compact protein active site. APE1, however, has demonstrated broad surgical expertise, and applies its DNA cleavage activity to a wide variety of DNA and RNA substrates. Here, we discuss what is known and unknown about APE1 cleavage mechanisms, focusing on structural and mechanistic considerations. Importantly, disruptions in the biological functions associated with APE1 are linked to numerous human maladies, including cancer and neurodegenerative diseases. The continued elucidation of APE1 mechanisms is required for rational drug design towards novel and strategic ways to target its associated repair pathways.
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Affiliation(s)
- Amy M Whitaker
- Department of Biochemistry and Molecular Biology, Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Bret D Freudenthal
- Department of Biochemistry and Molecular Biology, Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
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23
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Kumar M, Shukla VK, Misra PK, Raman MJ. Dysregulated Expression and Subcellular Localization of Base Excision Repair (BER) Pathway Enzymes in Gallbladder Cancer. INTERNATIONAL JOURNAL OF MOLECULAR AND CELLULAR MEDICINE 2018; 7:119-132. [PMID: 30276167 PMCID: PMC6148499 DOI: 10.22088/ijmcm.bums.7.2.119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2018] [Accepted: 08/14/2018] [Indexed: 01/06/2023]
Abstract
Base excision repair (BER) pathway is one of the repair systems that has an impact on radiotherapy and chemotherapy for cancer patients. The molecular pathogenesis of gallbladder cancer is not known extensively. In the present study we investigated whether the expression of AP endonuclease 1 (APE1) and DNA polymerase β (DNA pol β), key enzymes of BER pathway has any clinical significance with gallbladder carcinogenesis. 41 gallbladder cancer, 27 chronic cholecystitis, and 3 normal gallbladder specimens were analyzed for the expression of APE1 and DNA polymerase β by western blotting, and subcellular localization studied by immunohistochemistry. The enzymatic activity of APE1 was also studied. The correlations with expression of the above proteins with clinical-pathological characteristics of gallbladder cancer patients were analyzed. The integrated density value ratio (relative expression) of total APE1 (37 kDa + 35 kDa variant) analyzed in the three groups of tissues, was 0.76±0.03 in normal gallbladder, 0.91±0.08 in chronic cholecystitis, and 1.12±0.05 in gallbladder cancer. APE1 was found to be up-regulated in 80% of gallbladder carcinoma samples (P = 0.01). A positive trend of APE1 expression with tumor stage and lymph node positivity was observed. The enzymatic activity of APE1 was found higher in gallbladder cancer samples in comparison with chronic cholecystitis. The integrated density value ratio of DNA polymerase β for normal gallbladder, chronic cholecystitis and gallbladder cancer tissue samples were 0.46±0.03, 0.7±0.06 and 1.33±0.1, respectively. DNA polymerase β was found to be upregulated in almost all gallbladder carcinoma samples (P =0.0001), and its expression was negatively correlated with age (P=0.02). DNA polymerase β expression showed a positive trend with tumor stage and nuclear differentiation of gallbladder cancer. It may be concluded that alteration of these BER pathway proteins may be the causal factors for carcinogenesis of gallbladder, and has targeted therapeutic potential.
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Affiliation(s)
- Manoj Kumar
- Cytogenetics laboratory, Department of Zoology, Banaras Hindu University, Varanasi, India.,School of Biological and Environmental Sciences, Faculty of Basic Sciences, Shoolini University, Solan, Himachal Pradesh, India
| | - Vijay Kumar Shukla
- Department of General Surgery, Institute of Medical Science, Banaras Hindu University, Varanasi, India
| | - Pravas Kumar Misra
- Departments of Pathology and Surgery, Indian Railways Cancer Institute and Research Centre, Varanasi, Uttar Pradesh, India
| | - Mercy Jacob Raman
- Cytogenetics laboratory, Department of Zoology, Banaras Hindu University, Varanasi, India
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24
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Bhat AA, Lu H, Soutto M, Capobianco A, Rai P, Zaika A, El-Rifai W. Exposure of Barrett's and esophageal adenocarcinoma cells to bile acids activates EGFR-STAT3 signaling axis via induction of APE1. Oncogene 2018; 37:6011-6024. [PMID: 29991802 PMCID: PMC6328352 DOI: 10.1038/s41388-018-0388-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 05/24/2018] [Accepted: 05/25/2018] [Indexed: 02/06/2023]
Abstract
The development of Barret’s esophagus (BE) and its progression to esophageal adenocarcinoma (EAC) is highly linked to exposure to acidic bile salts due to chronic gastroesophageal reflux disease (GERD). In this study, we investigated the role of Apurinic/apyrimidinic endonuclease 1 /redox effector factor-1 (APE-1/REF-1) in STAT3 activation in response to EAC. Our results indicate that APE1 is constitutively overexpressed in EAC whereas its expression is transiently induced in response to acidic bile salts in non-neoplastic BE. Using overexpression or shRNA knockdown of APE1, we found that APE1 is required for phosphorylation, nuclear localization, and transcription activation of STAT3. By using an APE1 redox-specific mutant (C65A) and APE1 redox inhibitor (E3330), we demonstrate that APE1 activates STAT3 in a redox-dependent manner. By using pharmacologic inhibitors and genetic knockdown systems, we found that EGFR is a required link between APE1 and STAT3. EGFR phosphorylation (Y1068) was directly associated with APE1 levels and redox function. Co-immunoprecipitation and proximity ligation assays indicated that APE-1 coexists and interacts with the EGFR-STAT3 protein complex. Consistent with these findings, we demonstrated a significant induction in mRNA expression levels of STAT3 target genes (IL-6, IL-17A, BCL-xL, Survivin and c-Myc) in BE and EAC cells, following acidic bile salts treatment. ChIP assays indicated that acidic bile salts treatment enhances binding of STAT3 to the promoter of its target genes, Survivin and BCL-xL. Inhibition of APE1/REF-1 redox activity using E3330 abrogated STAT3 DNA binding and transcriptional activity. The induction of APE-1 - STAT3 axis in acidic bile salts conditions provided a survival advantage and promoted cellular proliferation. In summary, our study provides multiple pieces of evidence supporting a critical role for APE1 induction in activating the EGFR-STAT3 signaling axis in response to acidic bile salts, the main risk factors for Barrett’s carcinogenesis.
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Affiliation(s)
- Ajaz A Bhat
- Department of Surgery, Miller School of Medicine, University of Miami, Miami, FL, USA.,Division of Translational Medicine, Research Branch, Sidra Medicine, Doha, Qatar
| | - Heng Lu
- Department of Surgery, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Mohammed Soutto
- Department of Surgery, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Anthony Capobianco
- Department of Surgery, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Priyamvada Rai
- Department of Medicine, Division of Medical Oncology, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Alexander Zaika
- Department of Surgery, Miller School of Medicine, University of Miami, Miami, FL, USA.,Department of Veterans Affairs, Miami Healthcare System, Miami, FL, USA
| | - Wael El-Rifai
- Department of Surgery, Miller School of Medicine, University of Miami, Miami, FL, USA. .,Department of Veterans Affairs, Miami Healthcare System, Miami, FL, USA.
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25
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Sengupta S, Mantha AK, Song H, Roychoudhury S, Nath S, Ray S, Bhakat KK. Elevated level of acetylation of APE1 in tumor cells modulates DNA damage repair. Oncotarget 2018; 7:75197-75209. [PMID: 27655688 PMCID: PMC5342734 DOI: 10.18632/oncotarget.12113] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 09/02/2016] [Indexed: 12/20/2022] Open
Abstract
Apurinic/apyrimidinic (AP) sites are frequently generated in the genome by spontaneous depurination/depyrimidination or after removal of oxidized/modified bases by DNA glycosylases during the base excision repair (BER) pathway. Unrepaired AP sites are mutagenic and block DNA replication and transcription. The primary enzyme to repair AP sites in mammalian cells is AP endonuclease (APE1), which plays a key role in this repair pathway. Although overexpression of APE1 in diverse cancer types and its association with chemotherapeutic resistance are well documented, alteration of posttranslational modification of APE1 and modulation of its functions during tumorigenesis are largely unknown. Here, we show that both classical histone deacetylase HDAC1 and NAD+-dependent deacetylase SIRT1 regulate acetylation level of APE1 and acetylation of APE1 enhances its AP-endonuclease activity both in vitro and in cells. Modulation of APE1 acetylation level in cells alters AP site repair capacity of the cell extracts in vitro. Primary tumor tissues of diverse cancer types have higher level of acetylated APE1 (AcAPE1) compared to adjacent non-tumor tissue and exhibit enhanced AP site repair capacity. Importantly, in the absence of APE1 acetylation, cells accumulate AP sites in the genome and show increased sensitivity to DNA damaging agents. Together, our study demonstrates that elevation of acetylation level of APE1 in tumor could be a novel mechanism by which cells handle the elevated levels of DNA damages in response to genotoxic stress and maintain sustained proliferation.
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Affiliation(s)
- Shiladitya Sengupta
- Department of Biochemistry & Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA.,Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030 , USA
| | - Anil K Mantha
- Department of Biochemistry & Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA.,Center for Animal Sciences, School of Basic and Applied Sciences, Central University of Punjab, Bathinda 151001, Punjab, India
| | - Heyu Song
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Shrabasti Roychoudhury
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Somsubhra Nath
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA.,Molecular Biology Research & Diagnostic Laboratory, Saroj Gupta Cancer Centre & Research Institute, Kolkata 700063, India
| | - Sutapa Ray
- Department of Pediatrics, Hematology/Oncology Division, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Kishor K Bhakat
- Department of Biochemistry & Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA.,Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA
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26
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Liu Z, Yan H, Li H. Silencing of DNA repair sensitizes pediatric brain tumor cells to γ-irradiation using gold nanoparticles. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2017; 53:40-45. [PMID: 28501783 DOI: 10.1016/j.etap.2017.04.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Revised: 04/16/2017] [Accepted: 04/18/2017] [Indexed: 06/07/2023]
Abstract
We present a nanoparticle (NP)-mediated delivery vehicle that effectively carries and protects siRNA in pediatric ependymoma (EP) and medulloblastoma (MB) cells. The delivery vehicle consists of gold NPs coated with a polymeric shell comprising polyethylene glycol (PG), chitosan and polyethyleneimine (Au-CP-PEI). NPs loaded with siRNA knocked down Ape1 expression by over 75% in both MB and EP cells. Further, this reduction in Ape1 expression is associated with an increase in DNA damage after irradiation. The results indicate that NP-associated delivery of siApe1 is a feasible approach to circumventing pediatric brain tumor resistance to radiation therapy.
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Affiliation(s)
- Zuliang Liu
- Department of Pediatrics, Jiyang County People's Hospital, Ji'nan, Shandong 251400, China.
| | - Huiru Yan
- Department of Pediatrics, Jiyang County People's Hospital, Ji'nan, Shandong 251400, China
| | - Hongsha Li
- Department of Pediatrics, Jiyang County People's Hospital, Ji'nan, Shandong 251400, China
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27
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Kievit FM, Wang K, Ozawa T, Tarudji AW, Silber JR, Holland EC, Ellenbogen RG, Zhang M. Nanoparticle-mediated knockdown of DNA repair sensitizes cells to radiotherapy and extends survival in a genetic mouse model of glioblastoma. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2017; 13:2131-2139. [PMID: 28614736 DOI: 10.1016/j.nano.2017.06.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 05/19/2017] [Accepted: 06/04/2017] [Indexed: 12/12/2022]
Abstract
Glioblastoma (GBM) remains incurable, and recurrent tumors rarely respond to standard-of-care radiation and chemo-therapies. Therefore, strategies that enhance the effects of these therapies should provide significant benefits to GBM patients. We have developed a nanoparticle delivery vehicle that can stably bind and protect nucleic acids for specific delivery into brain tumor cells. These nanoparticles can deliver therapeutic siRNAs to sensitize GBM cells to radiotherapy and improve GBM treatment via systemic administration. We show that nanoparticle-mediated knockdown of the DNA repair protein apurinic endonuclease 1 (Ape1) sensitizes GBM cells to radiotherapy and extend survival in a genetic mouse model of GBM. Specific knockdown of Ape1 activity by 30% in brain tumor tissue doubled the extended survival achieved with radiotherapy alone. Ape1 is a promising target for increasing the effectiveness of radiotherapy, and nanoparticle-mediated delivery of siRNA is a promising strategy for tumor specific knockdown of Ape1.
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Affiliation(s)
- Forrest M Kievit
- Department of Neurological Surgery, University of Washington, Seattle, WA, United States; Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States
| | - Kui Wang
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, United States
| | - Tatsuya Ozawa
- Division of Human Biology and Solid Tumor Translational Research, Fred Hutchinson Cancer Research Center, Department of Neurosurgery and Alvord Brain Tumor Center, University of Washington, Seattle, WA, United States
| | - Aria W Tarudji
- Department of Biochemistry, University of Washington, Seattle, WA, United States
| | - John R Silber
- Department of Neurological Surgery, University of Washington, Seattle, WA, United States
| | - Eric C Holland
- Department of Neurological Surgery, University of Washington, Seattle, WA, United States; Division of Human Biology and Solid Tumor Translational Research, Fred Hutchinson Cancer Research Center, Department of Neurosurgery and Alvord Brain Tumor Center, University of Washington, Seattle, WA, United States
| | - Richard G Ellenbogen
- Department of Neurological Surgery, University of Washington, Seattle, WA, United States; Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States; Department of Radiology, University of Washington, Seattle, WA, United States.
| | - Miqin Zhang
- Department of Neurological Surgery, University of Washington, Seattle, WA, United States; Department of Materials Science and Engineering, University of Washington, Seattle, WA, United States; Department of Radiology, University of Washington, Seattle, WA, United States.
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28
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Abstract
Reduction-oxidation factor 1-apurinic/apyrimidinic endonuclease (Ref-1/APE1) is a critical node in tumor cells, both as a redox regulator of transcription factor activation and as part of the DNA damage response. As a redox signaling protein, Ref-1/APE1 enhances the transcriptional activity of STAT3, HIF-1α, nuclear factor kappa B, and other transcription factors to promote growth, migration, and survival in tumor cells as well as inflammation and angiogenesis in the tumor microenvironment. Ref-1/APE1 is activated in a variety of cancers, including prostate, colon, pancreatic, ovarian, lung and leukemias, leading to increased aggressiveness. Transcription factors downstream of Ref-1/APE1 are key contributors to many cancers, and Ref-1/APE1 redox signaling inhibition slows growth and progression in a number of tumor types. Ref-1/APE1 inhibition is also highly effective when paired with other drugs, including standard-of-care therapies and therapies targeting pathways affected by Ref-1/APE1 redox signaling. Additionally, Ref-1/APE1 plays a role in a variety of other indications, such as retinopathy, inflammation, and neuropathy. In this review, we discuss the functional consequences of activation of the Ref-1/APE1 node in cancer and other diseases, as well as potential therapies targeting Ref-1/APE1 and related pathways in relevant diseases. APX3330, a novel oral anticancer agent and the first drug to target Ref-1/APE1 for cancer is entering clinical trials and will be explored in various cancers and other diseases bringing bench discoveries to the clinic.
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29
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Laev SS, Salakhutdinov NF, Lavrik OI. Inhibitors of nuclease and redox activity of apurinic/apyrimidinic endonuclease 1/redox effector factor 1 (APE1/Ref-1). Bioorg Med Chem 2017; 25:2531-2544. [PMID: 28161249 DOI: 10.1016/j.bmc.2017.01.028] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 01/16/2017] [Accepted: 01/18/2017] [Indexed: 01/15/2023]
Abstract
Human apurinic/apyrimidinic endonuclease 1/redox effector factor 1 (APE1/Ref-1) is a multifunctional protein which is essential in the base excision repair (BER) pathway of DNA lesions caused by oxidation and alkylation. This protein hydrolyzes DNA adjacent to the 5'-end of an apurinic/apyrimidinic (AP) site to produce a nick with a 3'-hydroxyl group and a 5'-deoxyribose phosphate moiety or activates the DNA-binding activity of certain transcription factors through its redox function. Studies have indicated a role for APE1/Ref-1 in the pathogenesis of cancer and in resistance to DNA-interactive drugs. Thus, this protein has potential as a target in cancer treatment. As a result, major efforts have been directed to identify small molecule inhibitors against APE1/Ref-1 activities. These agents have the potential to become anticancer drugs. The aim of this review is to present recent progress in studies of all published small molecule APE1/Ref-1 inhibitors. The structures and activities of APE1/Ref-1 inhibitors, that target both DNA repair and redox activities, are presented and discussed. To date, there is an urgent need for further development of the design and synthesis of APE1/Ref-1 inhibitors due to high importance of this protein target.
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Affiliation(s)
- Sergey S Laev
- Vorozhtsov Institute of Organic Chemistry, Siberian Division, Russian Academy of Sciences, pr. akademika Lavrent'eva 9, Novosibirsk 630090, Russian Federation.
| | - Nariman F Salakhutdinov
- Vorozhtsov Institute of Organic Chemistry, Siberian Division, Russian Academy of Sciences, pr. akademika Lavrent'eva 9, Novosibirsk 630090, Russian Federation; Novosibirsk State University, Pirogova Str. 2, Novosibirsk 630090, Russian Federation
| | - Olga I Lavrik
- Novosibirsk State University, Pirogova Str. 2, Novosibirsk 630090, Russian Federation; Novosibirsk Institute of Chemical Biology and Fundamental Medicine, Siberian Division, Russian Academy of Sciences, pr. akademika Lavrent'eva 8, Novosibirsk 630090, Russian Federation
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30
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Scott TL, Wicker CA, Suganya R, Dhar B, Pittman T, Horbinski C, Izumi T. Polyubiquitination of apurinic/apyrimidinic endonuclease 1 by Parkin. Mol Carcinog 2016; 56:325-336. [PMID: 27148961 DOI: 10.1002/mc.22495] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 02/26/2016] [Accepted: 04/13/2016] [Indexed: 01/20/2023]
Abstract
Apurinic/apyrimidinic endonuclease 1 (APE1) is an essential protein crucial for repair of oxidized DNA damage not only in genomic DNA but also in mitochondrial DNA. Parkin, a tumor suppressor and Parkinson's disease (PD) associated gene, is an E3 ubiquitin ligase crucial for mitophagy. Although DNA damage is known to induce mitochondrial stress, Parkin's role in regulating DNA repair proteins has not been elucidated. In this study, we examined the possibility of Parkin-dependent ubiquitination of APE1. Ectopically expressed APE1 was degraded by Parkin and PINK1 via polyubiquitination in mouse embryonic fibroblast cells. PD-causing mutations in Parkin and PINK1 abrogated APE1 ubiquitination. Interaction of APE1 with Parkin was observed by co-immunoprecipitation, proximity ligation assay, and co-localization in the cytoplasm. N-terminal deletion of 41 amino acid residues in APE1 significantly reduced the Parkin-dependent APE1 degradation. These results suggested that Parkin directly ubiquitinated N-terminal Lys residues in APE1 in the cytoplasm. Modulation of Parkin and PINK1 activities under mitochondrial or oxidative stress caused moderate but statistically significant decrease of endogenous APE1 in human cell lines including SH-SY5Y, HEK293, and A549 cells. Analyses of glioblastoma tissues showed an inverse relation between the expression levels of APE1 and Parkin. These results suggest that degradation of endogenous APE1 by Parkin occur when cells are stressed to activate Parkin, and imply a role of Parkin in maintaining the quality of APE1, and loss of Parkin may contribute to elevated APE1 levels in glioblastoma. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Timothy L Scott
- Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, Kentucky
| | - Christina A Wicker
- Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, Kentucky
| | - Rangaswamy Suganya
- Radiation Oncology, Houston Methodist Research Institute, Houston, Texas
| | - Bithika Dhar
- Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, Kentucky
| | - Thomas Pittman
- Department of Neurosurgery, University of Kentucky, Lexington, Kentucky
| | - Craig Horbinski
- Departments of Pathology and Neurosurgery, Northwestern University, Chicago, Illinois
| | - Tadahide Izumi
- Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, Kentucky
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31
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Hsia KT, Liu CJ, Mar K, Lin LH, Lin CS, Cheng MF, Lee HS, Chiu SY. Impact of apurinic/apyrimidinic endonuclease 1/redox factor-1 on treatment response and survival in oral squamous cell carcinoma. Head Neck 2015; 38:550-9. [PMID: 25482590 DOI: 10.1002/hed.23927] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/03/2014] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Apurinic/apyrimidinic endonuclease 1/redox factor-1 (APE1/Ref-1) is a multifunctional protein involved in DNA repair and redox signaling. The purpose of this study was to investigate the relationship between APE1/Ref-1 expression and clinicopathological features, survival, and treatment response in patients with oral squamous cell carcinoma (OSCC) and cell lines. METHODS APE1/Ref-1 expression in OSCC was evaluated by immunohistochemistry, and its relationship to patient outcomes and treatment response was assessed statistically. The effects of stable short hairpin (sh)RNA-mediated knockdown of APE1/Ref-1 on cell survival, migration, and chemoradiation sensitivity were determined in OSCC cell lines. RESULTS APE1/Ref-1 immunostaining was correlated with positive lymph node status, and higher APE1/Ref-1 expression was significantly associated with poor prognosis and reduced treatment response. Consistent with the clinical studies, APE1/Ref-1 expression in OSCC cell lines was implicated in the regulation of migration and cisplatin-induced apoptosis. CONCLUSION Elevated APE1/Ref-1 expression may be used to predict poor survival and may confer chemoresistance in OSCC.
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Affiliation(s)
- Kan-Tai Hsia
- Institute of Oral Biology, School of Dentistry, National Yang-Ming University, Taipei, Taiwan
| | - Chung-Ji Liu
- Institute of Oral Biology, School of Dentistry, National Yang-Ming University, Taipei, Taiwan.,Department of Oral and Maxillofacial Surgery, Taipei Mackay Memorial Hospital, Taipei, Taiwan
| | - Kwei Mar
- Department of Dentistry, Zhongxiao Branch, Taipei City Hospital, Taipei, Taiwan
| | - Li-Han Lin
- Institute of Oral Biology, School of Dentistry, National Yang-Ming University, Taipei, Taiwan
| | - Chun-Shu Lin
- Department of Radiation Oncology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Ming-Fang Cheng
- Institute of Oral Biology, School of Dentistry, National Yang-Ming University, Taipei, Taiwan.,Department of Pathology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.,Division of Histological and Clinical Pathology, Hualien Armed Forced General Hospital, Hualien, Taiwan
| | - Herng-Sheng Lee
- Department of Pathology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Shang-Yi Chiu
- Institute of Oral Biology, School of Dentistry, National Yang-Ming University, Taipei, Taiwan
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32
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Sharbeen G, McCarroll J, Goldstein D, Phillips PA. Exploiting base excision repair to improve therapeutic approaches for pancreatic cancer. Front Nutr 2015; 2:10. [PMID: 25988138 PMCID: PMC4428371 DOI: 10.3389/fnut.2015.00010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 03/10/2015] [Indexed: 12/13/2022] Open
Abstract
Pancreatic ductal adenocarcinoma (PDA) is a highly chemoresistant and metastatic disease with a dismal 5-year survival rate of 6%. More effective therapeutic targets and approaches are urgently needed to tackle this devastating disease. The base excision repair (BER) pathway has been identified as a predictor of therapeutic response, prognostic factor, and therapeutic target in a variety of cancers. This review will discuss our current understanding of BER in PDA and its potential to improve PDA treatment.
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Affiliation(s)
- George Sharbeen
- Pancreatic Cancer Translational Research Group, Lowy Cancer Research Centre, Prince of Wales Clinical School, UNSW Australia , Sydney, NSW , Australia
| | - Joshua McCarroll
- Children's Cancer Institute, Lowy Cancer Research Centre, UNSW Australia , Sydney, NSW , Australia
| | - David Goldstein
- Pancreatic Cancer Translational Research Group, Lowy Cancer Research Centre, Prince of Wales Clinical School, UNSW Australia , Sydney, NSW , Australia
| | - Phoebe A Phillips
- Pancreatic Cancer Translational Research Group, Lowy Cancer Research Centre, Prince of Wales Clinical School, UNSW Australia , Sydney, NSW , Australia
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33
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Kievit FM, Stephen ZR, Wang K, Dayringer CJ, Sham JG, Ellenbogen RG, Silber JR, Zhang M. Nanoparticle mediated silencing of DNA repair sensitizes pediatric brain tumor cells to γ-irradiation. Mol Oncol 2015; 9:1071-80. [PMID: 25681012 DOI: 10.1016/j.molonc.2015.01.006] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 01/08/2015] [Accepted: 01/20/2015] [Indexed: 12/18/2022] Open
Abstract
Medulloblastoma (MB) and ependymoma (EP) are the most common pediatric brain tumors, afflicting 3000 children annually. Radiotherapy (RT) is an integral component in the treatment of these tumors; however, the improvement in survival is often accompanied by radiation-induced adverse developmental and psychosocial sequelae. Therefore, there is an urgent need to develop strategies that can increase the sensitivity of brain tumors cells to RT while sparing adjacent healthy brain tissue. Apurinic endonuclease 1 (Ape1), an enzyme in the base excision repair pathway, has been implicated in radiation resistance in cancer. Pharmacological and specificity limitations inherent to small molecule inhibitors of Ape1 have hindered their clinical development. Here we report on a nanoparticle (NP) based siRNA delivery vehicle for knocking down Ape1 expression and sensitizing pediatric brain tumor cells to RT. The NP comprises a superparamagnetic iron oxide core coated with a biocompatible, biodegradable coating of chitosan, polyethylene glycol (PEG), and polyethyleneimine (PEI) that is able to bind and protect siRNA from degradation and to deliver siRNA to the perinuclear region of target cells. NPs loaded with siRNA against Ape1 (NP:siApe1) knocked down Ape1 expression over 75% in MB and EP cells, and reduced Ape1 activity by 80%. This reduction in Ape1 activity correlated with increased DNA damage post-irradiation, which resulted in decreased cell survival in clonogenic assays. The sensitization was specific to therapies generating abasic lesions as evidenced by NP:siRNA not increasing sensitivity to paclitaxel, a microtubule disrupting agent. Our results indicate NP-mediated delivery of siApe1 is a promising strategy for circumventing pediatric brain tumor resistance to RT.
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Affiliation(s)
- Forrest M Kievit
- Department of Neurological Surgery, University of Washington, Seattle, WA 98195, USA
| | - Zachary R Stephen
- Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195, USA
| | - Kui Wang
- Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195, USA
| | - Christopher J Dayringer
- Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195, USA
| | - Jonathan G Sham
- Department of Surgery, University of Washington, Seattle, WA 98195, USA
| | - Richard G Ellenbogen
- Department of Neurological Surgery, University of Washington, Seattle, WA 98195, USA; Department of Radiology, University of Washington, Seattle, WA 98195, USA.
| | - John R Silber
- Department of Neurological Surgery, University of Washington, Seattle, WA 98195, USA
| | - Miqin Zhang
- Department of Neurological Surgery, University of Washington, Seattle, WA 98195, USA; Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195, USA; Department of Radiology, University of Washington, Seattle, WA 98195, USA.
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Chowdhury SM, Surhland C, Sanchez Z, Chaudhary P, Suresh Kumar MA, Lee S, Peña LA, Waring M, Sitharaman B, Naidu M. Graphene nanoribbons as a drug delivery agent for lucanthone mediated therapy of glioblastoma multiforme. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2014; 11:109-18. [PMID: 25131339 DOI: 10.1016/j.nano.2014.08.001] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 06/24/2014] [Accepted: 08/05/2014] [Indexed: 12/20/2022]
Abstract
We report use of PEG-DSPE coated oxidized graphene nanoribbons (O-GNR-PEG-DSPE) as agent for delivery of anti-tumor drug Lucanthone (Luc) into Glioblastoma Multiformae (GBM) cells targeting base excision repair enzyme APE-1 (Apurinic endonuclease-1). Lucanthone, an endonuclease inhibitor of APE-1, was loaded onto O-GNR-PEG-DSPEs using a simple non-covalent method. We found its uptake by GBM cell line U251 exceeding 67% and 60% in APE-1-overexpressing U251, post 24h. However, their uptake was ~38% and 29% by MCF-7 and rat glial progenitor cells (CG-4), respectively. TEM analysis of U251 showed large aggregates of O-GNR-PEG-DSPE in vesicles. Luc-O-GNR-PEG-DSPE was significantly toxic to U251 but showed little/no toxicity when exposed to MCF-7/CG-4 cells. This differential uptake effect can be exploited to use O-GNR-PEG-DSPEs as a vehicle for Luc delivery to GBM, while reducing nonspecific cytotoxicity to the surrounding healthy tissue. Cell death in U251 was necrotic, probably due to oxidative degradation of APE-1.
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Affiliation(s)
| | - Cassandra Surhland
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Zina Sanchez
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY, USA
| | - Pankaj Chaudhary
- Centre for Cancer Research and Cell Biology, Queens University Belfast, Belfast, UK
| | - M A Suresh Kumar
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY, USA
| | - Stephen Lee
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Louis A Peña
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA; Biosciences Department, Brookhaven National Laboratory, Upton, NY, USA
| | - Michael Waring
- Department of Pharmacology, Tennis Court Road, Cambridge University, Cambridge, UK
| | - Balaji Sitharaman
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA.
| | - Mamta Naidu
- GeneSys Research Institute/Center for Cancer Systems Biology at Tufts School of Medicine, Boston, MA, USA.
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Thakur S, Sarkar B, Cholia RP, Gautam N, Dhiman M, Mantha AK. APE1/Ref-1 as an emerging therapeutic target for various human diseases: phytochemical modulation of its functions. Exp Mol Med 2014; 46:e106. [PMID: 25033834 PMCID: PMC4119211 DOI: 10.1038/emm.2014.42] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 01/27/2014] [Accepted: 03/05/2014] [Indexed: 12/12/2022] Open
Abstract
Apurinic/apyrimidinic endonuclease 1 (APE1) is a multifunctional enzyme involved in the base excision repair (BER) pathway, which repairs oxidative base damage caused by endogenous and exogenous agents. APE1 acts as a reductive activator of many transcription factors (TFs) and has also been named redox effector factor 1, Ref-1. For example, APE1 activates activator protein-1, nuclear factor kappa B, hypoxia-inducible factor 1α, paired box gene 8, signal transducer activator of transcription 3 and p53, which are involved in apoptosis, inflammation, angiogenesis and survival pathways. APE1/Ref-1 maintains cellular homeostasis (redox) via the activation of TFs that regulate various physiological processes and that crosstalk with redox balancing agents (for example, thioredoxin, catalase and superoxide dismutase) by controlling levels of reactive oxygen and nitrogen species. The efficiency of APE1/Ref-1's function(s) depends on pairwise interaction with participant protein(s), the functions regulated by APE1/Ref-1 include the BER pathway, TFs, energy metabolism, cytoskeletal elements and stress-dependent responses. Thus, APE1/Ref-1 acts as a ‘hub-protein' that controls pathways that are important for cell survival. In this review, we will discuss APE1/Ref-1's versatile nature in various human etiologies, including neurodegeneration, cancer, cardiovascular and other diseases that have been linked with alterations in the expression, subcellular localization and activities of APE/Ref-1. APE1/Ref-1 can be targeted for therapeutic intervention using natural plant products that modulate the expression and functions of APE1/Ref-1. In addition, studies focusing on translational applications based on APE1/Ref-1-mediated therapeutic interventions are discussed.
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Affiliation(s)
- Shweta Thakur
- Center for Biosciences, School of Basic and Applied Sciences, Central University of Punjab, Punjab, India
| | - Bibekananda Sarkar
- Center for Biosciences, School of Basic and Applied Sciences, Central University of Punjab, Punjab, India
| | - Ravi P Cholia
- Center for Biosciences, School of Basic and Applied Sciences, Central University of Punjab, Punjab, India
| | - Nandini Gautam
- Center for Environmental Science and Technology, School of Environment and Earth Sciences, Central University of Punjab, Punjab, India
| | - Monisha Dhiman
- Center for Genetic Diseases and Molecular Medicine, School of Emerging Life Science Technologies, Central University of Punjab, Punjab, India
| | - Anil K Mantha
- 1] Center for Biosciences, School of Basic and Applied Sciences, Central University of Punjab, Punjab, India [2] Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA
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Mahjabeen I, Ali K, Zhou X, Kayani MA. Deregulation of base excision repair gene expression and enhanced proliferation in head and neck squamous cell carcinoma. Tumour Biol 2014; 35:5971-83. [PMID: 24622884 DOI: 10.1007/s13277-014-1792-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 02/24/2014] [Indexed: 12/21/2022] Open
Abstract
Defects in the DNA damage repair pathway contribute to cancer. The major pathway for oxidative DNA damage repair is base excision repair (BER). Although BER pathway genes (OGG1, APEX1 and XRCC1) have been investigated in a number of cancers, our knowledge on the prognostic significance of these genes and their role in head and neck squamous cell carcinoma is limited. Protein levels of OGG1, APEX1 and XRCC1 and a proliferation marker, Ki-67, were examined by immunohistochemical analysis, in a cohort of 50 HNSCC patients. Significant downregulation of OGG1 (p<0.04) and XRCC1 (p<0.05) was observed in poorly differentiated HNSCC compared to mod-well-differentiated cases. Significant upregulation of APEX1 (p<0.05) and Ki-67 (p<0.05) was observed in poorly differentiated HNSCC compared to mod-well-differentiated cases. Significant correlation was observed between XRCC1 and OGG1 (r=0.33, p<0.02). Inverse correlations were observed between OGG1 and Ki-67 (r=-0.377, p<0.005), between APEX1 and XRCC1 (r=-0.435, p<0.002) and between OGG1 and APEX1 (r=-0.34, p<0.02) in HNSCC. To confirm our observations, we examined BER pathway genes and a proliferation marker, Ki-67, expression at the mRNA level on 50 head and neck squamous cell carcinoma (HNSCC) and 50 normal control samples by quantitative real-time polymerase chain reaction. Significant downregulation was observed in case of OGG1 (p<0.04) and XRCC1 (p<0.02), while significant upregulation was observed in case of APEX1 (p<0.01) and Ki-67 (p<0.03) in HNSCC tissue samples compared to controls. Our data suggested that deregulation of base excision repair pathway genes, such as OGG1, APEX1 and XRCC1, combined with overexpression of Ki-67, a marker for excessive proliferation, may contribute to progression of HNSCC in Pakistani population.
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Affiliation(s)
- Ishrat Mahjabeen
- Cancer Genetics Lab, Department of Biosciences, COMSATS Institute of Information and Technology, Park Road Chakshazad, Islamabad, Pakistan
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Abstract
SIGNIFICANCE Human apurinic/apyrimidinic endonuclease 1 (APE1, also known as REF-1) was isolated based on its ability to cleave at AP sites in DNA or activate the DNA binding activity of certain transcription factors. We review herein topics related to this multi-functional DNA repair and stress-response protein. RECENT ADVANCES APE1 displays homology to Escherichia coli exonuclease III and is a member of the divalent metal-dependent α/β fold-containing phosphoesterase superfamily of enzymes. APE1 has acquired distinct active site and loop elements that dictate substrate selectivity, and a unique N-terminus which at minimum imparts nuclear targeting and interaction specificity. Additional activities ascribed to APE1 include 3'-5' exonuclease, 3'-repair diesterase, nucleotide incision repair, damaged or site-specific RNA cleavage, and multiple transcription regulatory roles. CRITICAL ISSUES APE1 is essential for mouse embryogenesis and contributes to cell viability in a genetic background-dependent manner. Haploinsufficient APE1(+/-) mice exhibit reduced survival, increased cancer formation, and cellular/tissue hyper-sensitivity to oxidative stress, supporting the notion that impaired APE1 function associates with disease susceptibility. Although abnormal APE1 expression/localization has been seen in cancer and neuropathologies, and impaired-function variants have been described, a causal link between an APE1 defect and human disease remains elusive. FUTURE DIRECTIONS Ongoing efforts aim at delineating the biological role(s) of the different APE1 activities, as well as the regulatory mechanisms for its intra-cellular distribution and participation in diverse molecular pathways. The determination of whether APE1 defects contribute to human disease, particularly pathologies that involve oxidative stress, and whether APE1 small-molecule regulators have clinical utility, is central to future investigations.
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Affiliation(s)
- Mengxia Li
- Intramural Research Program, Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health , Baltimore, Maryland
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Nagoya H, Futagami S, Shimpuku M, Tatsuguchi A, Wakabayashi T, Yamawaki H, Kodaka Y, Kawagoe T, Watarai Y, Makino H, Miyashita M, Tsuchiya S, Crowe SE, Sakamoto C. Apurinic/apyrimidinic endonuclease-1 is associated with angiogenesis and VEGF production via upregulation of COX-2 expression in esophageal cancer tissues. Am J Physiol Gastrointest Liver Physiol 2014; 306:G183-90. [PMID: 24284961 PMCID: PMC5142390 DOI: 10.1152/ajpgi.00057.2013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Apurinic/apyrimidinic endonuclease-1 (APE-1) is a key enzyme responsible for DNA base excision repair and is also a multifunctional protein such as redox effector for several transcriptional factors. Our study was designed to investigate APE-1 expression and to study its interaction with cyclooxygenase (COX)-2 expression and VEGF production in the esophageal cancer. The expression of APE-1, COX-2, monocyte chemoattractant protein (MCP)-1, CC-chemokine receptor (CCR)2, and VEGF were evaluated by immunohistochemistry in 65 human esophageal squamous cell carcinoma (ESCC) tissues. Real-time PCR and Western blotting were performed to detect mRNA and protein expression of APE-1 and p-signal transducer and activator of transcription 3 (STAT3) expression in MCP-1-stimulated ESCC cell lines (KYSE 220 and EC-GI-10). siRNA for APE-1 was treated to determine the role of APE-1 in the regulation of COX-2 expression, VEGF production, and antiapoptotic effect against cisplatin. In human ESCC tissues, nuclear localization of APE-1 was observed in 92.3% (60/65) of all tissues. There was a significant relationship (P = 0.029, R = 0.49) between nuclear APE-1 and cytoplasmic COX-2 expression levels in the esophageal cancer tissues. In KYSE 220 and EC-GI-10 cells, MCP-1 stimulation significantly increased mRNA and protein expression of APE-1. Treatment with siRNA for APE-1 significantly inhibited p-STAT3 expression levels in MCP-1-stimulated cells. Furthermore, treatment of siRNA for APE-1 significantly reduced COX-2 expression and VEGF production in MCP-1-stimulated esophageal cancer cell lines. Treatment with APE-1 siRNA significantly increased apoptotic levels in cisplatin-incubated KYSE 220 and EC-GI-10 cells. We concluded that APE-1 is overexpressed and associated with COX-2 expression and VEGF production in esophageal cancer tissues.
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Affiliation(s)
- Hiroyuki Nagoya
- 1Division of Gastroenterology, Department of Internal Medicine,
| | - Seiji Futagami
- 1Division of Gastroenterology, Department of Internal Medicine,
| | - Mayumi Shimpuku
- 1Division of Gastroenterology, Department of Internal Medicine,
| | | | | | | | - Yasuhiro Kodaka
- 1Division of Gastroenterology, Department of Internal Medicine,
| | - Tetsuro Kawagoe
- 1Division of Gastroenterology, Department of Internal Medicine,
| | | | - Hiroshi Makino
- 3Department of Surgery, Nippon Medical School, Bunkyo-ku, Tokyo, Japan;
| | - Masao Miyashita
- 3Department of Surgery, Nippon Medical School, Bunkyo-ku, Tokyo, Japan;
| | | | - Sheila E. Crowe
- 4Division of Gastroenterology, Department of Medicine, University of California, San Diego, California
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Sudhakar J, Khetan V, Madhusudan S, Krishnakumar S. Dysregulation of human apurinic/apyrimidinic endonuclease 1 (APE1) expression in advanced retinoblastoma. Br J Ophthalmol 2014; 98:402-7. [DOI: 10.1136/bjophthalmol-2013-304166] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Wang M, Chu H, Wang S, Wang M, Wang W, Han S, Zhang Z. Genetic variant in APE1 gene promoter contributes to cervical cancer risk. Am J Obstet Gynecol 2013; 209:360.e1-7. [PMID: 23871947 DOI: 10.1016/j.ajog.2013.07.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 02/21/2013] [Accepted: 07/10/2013] [Indexed: 12/27/2022]
Abstract
OBJECTIVE Apurinic/apyrimidinic endonuclease 1 (APE1) is an essential enzyme in the base excision repair pathway, which plays an important role in repairing DNA damage caused by oxidation and alkylation. However, the exact mechanism of APE1 associated with cervical cancer risk is still unknown. In this study, we explored whether the APE1 -656T>G polymorphism contributed to the risk of cervical cancer. STUDY DESIGN In the hospital-based case-control study, 306 cervical cancer cases and 306 cancer-free controls were genotyped for the APE1 -656T>G polymorphism using the polymerase chain reaction restriction fragment length polymorphism method. Luciferase reporter assay and electrophoretic mobility shift assay were used to evaluate the APE1 transcriptional activity and the binding ability of transcriptional factors to the APE1 promoter, respectively. RESULTS Logistic regression analysis showed that individuals with the APE1 -656 TG/GG genotypes had a significantly reduced risk of cervical cancer compared with the TT genotype (adjusted odds ratio, 0.61; 95% confidence interval, 0.42-0.89). The luciferase assays in 3 cell lines showed that the APE1 -656T>G substitution can increase the expression of APE1, which was consistent with the finding of association study. Electrophoretic mobility shift assay further indicated that the APE1 -656T>G polymorphism enhanced the binding affinity of transcriptional factors to the promoter region. CONCLUSION These findings suggested that the APE1 -656T>G polymorphism was associated with cervical cancer risk in a Chinese population by affecting the binding affinity of transcriptional factors to the promoter, leading to an increased expression level of APE1.
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Chen S, Xiong G, Wu S, Mo J. Downregulation of apurinic/apyrimidinic endonuclease 1/redox factor-1 enhances the sensitivity of human pancreatic cancer cells to radiotherapy in vitro. Cancer Biother Radiopharm 2012; 28:169-76. [PMID: 23268706 DOI: 10.1089/cbr.2012.1266] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
UNLABELLED Abstract Background: Radiotherapy is an important treatment for the patients with advanced pancreatic cancer. Emerging studies determined apurinic/apyrimidinic endonuclease 1/redox factor-1 (APE1/Ref-1) might associate with the resistance of human pancreatic cancer cells to radiotherapy. AIMS To investigate whether downregulation of APE1/Ref-1 expression by ribonucleic acid interference would increase the sensitivity of chromic-P32 phosphate to pancreatic cancer cells. METHODS The plasmids containing APE-specific and unspecific short hairpin were transfected into Patu-8898 cells. Stable cell clones were selected by G418. The mRNA expression of APE1/Ref-1 was detected by semiquantitative reverse transcription-polymerase chain reaction and the protein expression of APE1/Ref-1 was detected by Western blot analysis; cell proliferation was studied by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and colony formation assay; apoptosis was detected by flow cytometry. RESULTS After 24 hours irradiation, APE1/Ref-1 mRNA and protein expression were upregulated, in a concentration-dependent manner. Suppression of APE1/Ref-1 by siRNA increased the pancreatic cancer cells hypersensitive to (32)P-CP. In the combination of (32)P-CP and siRNA group, MTT assay showed that the cell inhibition increased to (74.33%±9.02%), the surviving fraction in the colony formation assay was only 25.00%, and the apoptosis rate was up to (16.77%±0.98%). CONCLUSIONS Knockdown APE1/Ref-1 gene expression may significantly sensitize the Patu-8988 cells to radiotherapy, which may be a useful target for modifying radiation resistance of pancreatic cancer cells to irradiation.
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Affiliation(s)
- Sumei Chen
- Division of Gastroenterology and Hepatology, Shanghai Institute of Digestive Disease, Shanghai Jiao-Tong University School of Medicine Renji Hospital, Shanghai, China
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Bobola MS, Kolstoe DD, Blank A, Chamberlain MC, Silber JR. Repair of 3-methyladenine and abasic sites by base excision repair mediates glioblastoma resistance to temozolomide. Front Oncol 2012; 2:176. [PMID: 23230562 PMCID: PMC3515961 DOI: 10.3389/fonc.2012.00176] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 11/05/2012] [Indexed: 12/11/2022] Open
Abstract
Alkylating agents have long played a central role in the adjuvant therapy of glioblastoma (GBM). More recently, inclusion of temozolomide (TMZ), an orally administered methylating agent with low systemic toxicity, during and after radiotherapy has markedly improved survival. Extensive in vitro and in vivo evidence has shown that TMZ-induced O(6)-methylguanine (O(6)-meG) mediates GBM cell killing. Moreover, low or absent expression of O(6)-methylguanine-DNA methyltransferase (MGMT), the sole human repair protein that removes O(6)-meG from DNA, is frequently associated with longer survival in GBMs treated with TMZ, promoting interest in developing inhibitors of MGMT to counter resistance. However, the clinical efficacy of TMZ is unlikely to be due solely to O(6)-meG, as the agent produces approximately a dozen additional DNA adducts, including cytotoxic N3-methyladenine (3-meA) and abasic sites. Repair of 3-meA and abasic sites, both of which are produced in greater abundance than O(6)-meG, is mediated by the base excision repair (BER) pathway, and occurs independently of removal of O(6)-meG. These observations indicate that BER activities are also potential targets for strategies to potentiate TMZ cytotoxicity. Here we review the evidence that 3-meA and abasic sites mediate killing of GBM cells. We also present in vitro and in vivo evidence that alkyladenine-DNA glycosylase, the sole repair activity that excises 3-meA from DNA, and Ape1, the major human abasic site endonuclease, mediate TMZ resistance in GBMs and represent potential anti-resistance targets.
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Affiliation(s)
- Michael S. Bobola
- Department of Neurological Surgery, University of Washington Medical CenterSeattle, WA, USA
| | - Douglas D. Kolstoe
- Department of Neurological Surgery, University of Washington Medical CenterSeattle, WA, USA
| | - A. Blank
- Department of Neurological Surgery, University of Washington Medical CenterSeattle, WA, USA
| | - Marc C. Chamberlain
- Department of Neurological Surgery, University of Washington Medical CenterSeattle, WA, USA
- Department of Neurology, University of Washington Medical CenterSeattle, WA, USA
| | - John R. Silber
- Department of Neurological Surgery, University of Washington Medical CenterSeattle, WA, USA
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Small-molecule inhibitors of DNA damage-repair pathways: an approach to overcome tumor resistance to alkylating anticancer drugs. Future Med Chem 2012; 4:1093-111. [PMID: 22709253 DOI: 10.4155/fmc.12.58] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
A major challenge in the future development of cancer therapeutics is the identification of biological targets and pathways, and the subsequent design of molecules to combat the drug-resistant cells hiding in virtually all cancers. This therapeutic approach is justified based upon the limited advances in cancer cures over the past 30 years, despite the development of many novel chemotherapies and earlier detection, which often fail due to drug resistance. Among the various targets to overcome tumor resistance are the DNA repair systems that can reverse the cytotoxicity of many clinically used DNA-damaging agents. Some progress has already been made but much remains to be done. We explore some components of the DNA-repair process, which are involved in repair of alkylation damage of DNA, as targets for the development of novel and effective molecules designed to improve the efficacy of existing anticancer drugs.
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Kim YJ, Wilson DM. Overview of base excision repair biochemistry. Curr Mol Pharmacol 2012; 5:3-13. [PMID: 22122461 DOI: 10.2174/1874467211205010003] [Citation(s) in RCA: 218] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Accepted: 11/25/2010] [Indexed: 02/06/2023]
Abstract
Base excision repair (BER) is an evolutionarily conserved pathway, which could be considered the "workhorse" repair mechanism of the cell. In particular, BER corrects most forms of spontaneous hydrolytic decay products in DNA, as well as everyday oxidative and alkylative modifications to bases or the sugar phosphate backbone. The repair response involves five key enzymatic steps that aim to remove the initial DNA lesion and restore the genetic material back to its original state: (i) excision of a damaged or inappropriate base, (ii) incision of the phosphodiester backbone at the resulting abasic site, (iii) termini clean-up to permit unabated repair synthesis and/or nick ligation, (iv) gap-filling to replace the excised nucleotide, and (v) sealing of the final, remaining DNA nick. These repair steps are executed by a collection of enzymes that include DNA glycosylases, apurinic/apyrimidinic endonucleases, phosphatases, phosphodiesterases, kinases, polymerases and ligases. Defects in BER components lead to reduced cell survival, elevated mutation rates, and DNA-damaging agent hypersensitivities. In addition, the pathway plays a significant role in determining cellular responsiveness to relevant clinical anti-cancer agents, such as alkylators (e.g. temozolomide), nucleoside analogs (e.g. 5-fluorouracil), and ionizing radiation. The molecular details of BER and the contribution of the pathway to therapeutic agent resistance are reviewed herein.
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Affiliation(s)
- Yun-Jeong Kim
- Laboratory of Molecular Gerontology, Biomedical Research Center, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
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Srinivasan A, Wang L, Cline CJ, Xie Z, Sobol RW, Xie XQ, Gold B. Identification and characterization of human apurinic/apyrimidinic endonuclease-1 inhibitors. Biochemistry 2012; 51:6246-59. [PMID: 22788932 DOI: 10.1021/bi300490r] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The repair of abasic sites that arise in DNA from hydrolytic depurination/depyrimidination of the nitrogenous bases from the sugar-phosphate backbone and the action of DNA glycosylases on deaminated, oxidized, and alkylated bases are critical to cell survival. Apurinic/apyrimidinic endonuclease-1/redox effector factor-1 (APE-1; aka APE1/ref-1) is responsible for the initial removal of abasic lesions as part of the base excision repair pathway. Deletion of APE-1 activity is embryonic lethal in animals and is lethal in cells. Potential inhibitors of the repair function of APE-1 were identified based upon molecular modeling of the crystal structure of the APE-1 protein. We describe the characterization of several unique nanomolar inhibitors using two complementary biochemical screens. The most active molecules all contain a 2-methyl-4-amino-6,7-dioxolo-quinoline structure that is predicted from the modeling to anchor the compounds in the endonuclease site of the protein. The mechanism of action of the selected compounds was probed by fluorescence and competition studies, which indicate, in a specific case, direct interaction between the inhibitor and the active site of the protein. It is demonstrated that the inhibitors induce time-dependent increases in the accumulation of abasic sites in cells at levels that correlate with their potency to inhibit APE-1 endonuclease excision. The inhibitor molecules also potentiate by 5-fold the toxicity of a DNA methylating agent that creates abasic sites. The molecules represent a new class of APE-1 inhibitors that can be used to probe the biology of this critical enzyme and to sensitize resistant tumor cells to the cytotoxicity of clinically used DNA damaging anticancer drugs.
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Affiliation(s)
- Ajay Srinivasan
- Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261, USA
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Sensitizing effect of silencing Ape1/Ref-1 on doxorubicin-induced apoptosis in human carcinoma cells. Mol Cell Toxicol 2012. [DOI: 10.1007/s13273-011-0049-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Prognostic Significance of Human Apurinic/Apyrimidinic Endonuclease (APE/Ref-1) Expression in Rectal Cancer Treated With Preoperative Radiochemotherapy. Int J Radiat Oncol Biol Phys 2012; 82:130-7. [DOI: 10.1016/j.ijrobp.2010.09.037] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Revised: 08/06/2010] [Accepted: 09/10/2010] [Indexed: 11/24/2022]
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Hegde ML, Izumi T, Mitra S. Oxidized base damage and single-strand break repair in mammalian genomes: role of disordered regions and posttranslational modifications in early enzymes. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012; 110:123-53. [PMID: 22749145 DOI: 10.1016/b978-0-12-387665-2.00006-7] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Oxidative genome damage induced by reactive oxygen species includes oxidized bases, abasic (AP) sites, and single-strand breaks, all of which are repaired via the evolutionarily conserved base excision repair/single-strand break repair (BER/SSBR) pathway. BER/SSBR in mammalian cells is complex, with preferred and backup sub-pathways, and is linked to genome replication and transcription. The early BER/SSBR enzymes, namely, DNA glycosylases (DGs) and the end-processing proteins such as abasic endonuclease 1 (APE1), form complexes with downstream repair (and other noncanonical) proteins via pairwise interactions. Furthermore, a unique feature of mammalian early BER/SSBR enzymes is the presence of a disordered terminal extension that is absent in their Escherichia coli prototypes. These nonconserved segments usually contain organelle-targeting signals, common interaction interfaces, and sites of posttranslational modifications that may be involved in regulating their repair function including lesion scanning. Finally, the linkage of BER/SSBR deficiency to cancer, aging, and human neurodegenerative diseases, and therapeutic targeting of BER/SSBR are discussed.
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Affiliation(s)
- Muralidhar L Hegde
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas, USA
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Naidu MD, Agarwal R, Pena LA, Cunha L, Mezei M, Shen M, Wilson DM, Liu Y, Sanchez Z, Chaudhary P, Wilson SH, Waring MJ. Lucanthone and its derivative hycanthone inhibit apurinic endonuclease-1 (APE1) by direct protein binding. PLoS One 2011; 6:e23679. [PMID: 21935361 PMCID: PMC3174134 DOI: 10.1371/journal.pone.0023679] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Accepted: 07/23/2011] [Indexed: 01/06/2023] Open
Abstract
Lucanthone and hycanthone are thioxanthenone DNA intercalators used in the 1980s as antitumor agents. Lucanthone is in Phase I clinical trial, whereas hycanthone was pulled out of Phase II trials. Their potential mechanism of action includes DNA intercalation, inhibition of nucleic acid biosyntheses, and inhibition of enzymes like topoisomerases and the dual function base excision repair enzyme apurinic endonuclease 1 (APE1). Lucanthone inhibits the endonuclease activity of APE1, without affecting its redox activity. Our goal was to decipher the precise mechanism of APE1 inhibition as a prerequisite towards development of improved therapeutics that can counteract higher APE1 activity often seen in tumors. The IC(50) values for inhibition of APE1 incision of depurinated plasmid DNA by lucanthone and hycanthone were 5 µM and 80 nM, respectively. The K(D) values (affinity constants) for APE1, as determined by BIACORE binding studies, were 89 nM for lucanthone/10 nM for hycanthone. APE1 structures reveal a hydrophobic pocket where hydrophobic small molecules like thioxanthenones can bind, and our modeling studies confirmed such docking. Circular dichroism spectra uncovered change in the helical structure of APE1 in the presence of lucanthone/hycanthone, and notably, this effect was decreased (Phe266Ala or Phe266Cys or Trp280Leu) or abolished (Phe266Ala/Trp280Ala) when hydrophobic site mutants were employed. Reduced inhibition by lucanthone of the diminished endonuclease activity of hydrophobic mutant proteins (as compared to wild type APE1) supports that binding of lucanthone to the hydrophobic pocket dictates APE1 inhibition. The DNA binding capacity of APE1 was marginally inhibited by lucanthone, and not at all by hycanthone, supporting our hypothesis that thioxanthenones inhibit APE1, predominantly, by direct interaction. Finally, lucanthone-induced degradation was drastically reduced in the presence of short and long lived free radical scavengers, e.g., TRIS and DMSO, suggesting that the mechanism of APE1 breakdown may involve free radical-induced peptide bond cleavage.
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Affiliation(s)
- Mamta D Naidu
- Biology Department, Brookhaven National Laboratory, Upton, New York, United States of America.
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Busso CS, Wedgeworth CM, Izumi T. Ubiquitination of human AP-endonuclease 1 (APE1) enhanced by T233E substitution and by CDK5. Nucleic Acids Res 2011; 39:8017-28. [PMID: 21727086 PMCID: PMC3185409 DOI: 10.1093/nar/gkr401] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Apurinic/apyrimidinic endonuclease-1 (APE1) is a multifunctional DNA repair/gene regulatory protein in mammalian cells, and was recently reported to be phosphorylated at Thr233 by CDK5. We here report that ubiquitination of T233E APE1, a mimicry of phospho-T233 APE1, was markedly increased in multiple cell lines. Expression of CDK5 enhanced monoubiquitination of endogenous APE1. Polyubiquitinated APE1 was decreased when K48R ubiquitin was expressed, suggesting that polyubiquitination was mediated mainly through Lys48 of ubiquitin. The ubiquitination activity of MDM2, consistent in its role for APE1 ubiquitination, was increased for T233E APE1 compared to the wild-type APE1. In mouse embryonic fibroblasts lacking the MDM2 gene, ubiquitination of T233E APE1 was still observed probably because of the decreased degradation activity for monoubiquitinated APE1 and because of backup E3 ligases in the cells. Monoubiquitinated APE1 was present in the nucleus, and analyzing global gene expression profiles with or without induction of a ubiquitin-APE1 fusion gene suggested that monoubiquitination enhanced the gene suppression activity of APE1. These data reveal a delicate balance of ubiquitination and phosphorylation activities that alter the gene regulatory function of APE1.
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Affiliation(s)
- Carlos S Busso
- Department of Otolaryngology, Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
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