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Jawich D, Pfohl-Leszkowicz A, Lteif R, Strehaiano P. DNA adduct formation in Saccharomyces cerevisiae following exposure to environmental pollutants, as in vivo model for molecular toxicity studies. World J Microbiol Biotechnol 2024; 40:180. [PMID: 38668960 DOI: 10.1007/s11274-024-03989-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Accepted: 04/15/2024] [Indexed: 05/18/2024]
Abstract
DNA adduction in the model yeast Saccharomyces cerevisiae was investigated after exposure to the fungicide penconazole and the reference genotoxic compound benzo(a)pyrene, for validating yeasts as a tool for molecular toxicity studies, particularly of environmental pollution. The effect of the toxicants on the yeast's growth kinetics was determined as an indicator of cytotoxicity. Fermentative cultures of S. cerevisiae were exposed to 2 ppm of Penconazole during different phases of growth; while 0.2 and 2 ppm of benzo(a)pyrene were applied to the culture medium before inoculation and on exponential cultures. Exponential respiratory cultures were also exposed to 0.2 ppm of B(a)P for comparison of both metabolisms. Penconazole induced DNA adducts formation in the exponential phase test; DNA adducts showed a peak of 54.93 adducts/109 nucleotides. Benzo(a)pyrene induced the formation of DNA adducts in all the tests carried out; the highest amount of 46.7 adducts/109 nucleotides was obtained in the fermentative cultures after the exponential phase exposure to 0.2 ppm; whereas in the respiratory cultures, 14.6 adducts/109 nucleotides were detected. No cytotoxicity was obtained in any experiment. Our study showed that yeast could be used to analyse DNA adducts as biomarkers of exposure to environmental toxicants.
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Affiliation(s)
- Dalal Jawich
- Fanar Laboratory, Lebanese Agricultural Research Institute (LARI), Beirut, Lebanon.
- Laboratoire de Génie Chimique, UMR-CNRS/INPT/UPS 5503, Département Bioprocédé-Système Microbien, Toulouse Cedex, France.
- Unité de Technologie et Valorisation Alimentaire, Faculté Des Sciences, Centre d'Analyses et de Recherche, Université Saint-Joseph de Beyrouth, Campus des Sciences et Technologies, Mar Roukos, Dekwaneh, B.P. 17-5208, Mar Mikhaël, Beirut, 1104 2020, Lebanon.
- Faculty of Agricultural Sciences, Department of Basic Sciences, Lebanese University, Dekwaneh, Beirut, Lebanon.
| | - Annie Pfohl-Leszkowicz
- Laboratoire de Génie Chimique, UMR-CNRS/INPT/UPS 5503, Département Bioprocédé-Système Microbien, Toulouse Cedex, France
| | - Roger Lteif
- Unité de Technologie et Valorisation Alimentaire, Faculté Des Sciences, Centre d'Analyses et de Recherche, Université Saint-Joseph de Beyrouth, Campus des Sciences et Technologies, Mar Roukos, Dekwaneh, B.P. 17-5208, Mar Mikhaël, Beirut, 1104 2020, Lebanon
| | - Pierre Strehaiano
- Laboratoire de Génie Chimique, UMR-CNRS/INPT/UPS 5503, Département Bioprocédé-Système Microbien, Toulouse Cedex, France
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Harnessing DNA Replication Stress for Novel Cancer Therapy. Genes (Basel) 2020; 11:genes11090990. [PMID: 32854236 PMCID: PMC7564951 DOI: 10.3390/genes11090990] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 08/03/2020] [Accepted: 08/20/2020] [Indexed: 12/16/2022] Open
Abstract
DNA replication is the fundamental process for accurate duplication and transfer of genetic information. Its fidelity is under constant stress from endogenous and exogenous factors which can cause perturbations that lead to DNA damage and defective replication. This can compromise genomic stability and integrity. Genomic instability is considered as one of the hallmarks of cancer. In normal cells, various checkpoints could either activate DNA repair or induce cell death/senescence. Cancer cells on the other hand potentiate DNA replicative stress, due to defective DNA damage repair mechanism and unchecked growth signaling. Though replicative stress can lead to mutagenesis and tumorigenesis, it can be harnessed paradoxically for cancer treatment. Herein, we review the mechanism and rationale to exploit replication stress for cancer therapy. We discuss both established and new approaches targeting DNA replication stress including chemotherapy, radiation, and small molecule inhibitors targeting pathways including ATR, Chk1, PARP, WEE1, MELK, NAE, TLK etc. Finally, we review combination treatments, biomarkers, and we suggest potential novel methods to target DNA replication stress to treat cancer.
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Shetty M, Noguchi C, Wilson S, Martinez E, Shiozaki K, Sell C, Mell JC, Noguchi E. Maf1-dependent transcriptional regulation of tRNAs prevents genomic instability and is associated with extended lifespan. Aging Cell 2020; 19:e13068. [PMID: 31833215 PMCID: PMC6996946 DOI: 10.1111/acel.13068] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 10/17/2019] [Accepted: 10/18/2019] [Indexed: 12/18/2022] Open
Abstract
Maf1 is the master repressor of RNA polymerase III responsible for transcription of tRNAs and 5S rRNAs. Maf1 is negatively regulated via phosphorylation by the mTOR pathway, which governs protein synthesis, growth control, and lifespan regulation in response to nutrient availability. Inhibiting the mTOR pathway extends lifespan in various organisms. However, the downstream effectors for the regulation of cell homeostasis that are critical to lifespan extension remain elusive. Here we show that fission yeast Maf1 is required for lifespan extension. Maf1's function in tRNA repression is inhibited by mTOR-dependent phosphorylation, whereas Maf1 is activated via dephosphorylation by protein phosphatase complexes, PP4 and PP2A. Mutational analysis reveals that Maf1 phosphorylation status influences lifespan, which is correlated with elevated tRNA and protein synthesis levels in maf1∆ cells. However, mTOR downregulation, which negates protein synthesis, fails to rescue the short lifespan of maf1∆ cells, suggesting that elevated protein synthesis is not a cause of lifespan shortening in maf1∆ cells. Interestingly, maf1∆ cells accumulate DNA damage represented by formation of Rad52 DNA damage foci and Rad52 recruitment at tRNA genes. Loss of the Rad52 DNA repair protein further exacerbates the shortened lifespan of maf1∆ cells. Strikingly, PP4 deletion alleviates DNA damage and rescues the short lifespan of maf1∆ cells even though tRNA synthesis is increased in this condition, suggesting that elevated DNA damage is the major cause of lifespan shortening in maf1∆ cells. We propose that Maf1-dependent inhibition of tRNA synthesis controls fission yeast lifespan by preventing genomic instability that arises at tRNA genes.
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Affiliation(s)
- Mihir Shetty
- Department of Biochemistry and Molecular BiologyDrexel University College of MedicinePhiladelphiaPAUSA
| | - Chiaki Noguchi
- Department of Biochemistry and Molecular BiologyDrexel University College of MedicinePhiladelphiaPAUSA
| | - Sydney Wilson
- Department of Biochemistry and Molecular BiologyDrexel University College of MedicinePhiladelphiaPAUSA
| | - Esteban Martinez
- Department of Biochemistry and Molecular BiologyDrexel University College of MedicinePhiladelphiaPAUSA
- Present address:
Fox Chase Cancer CenterPhiladelphiaPAUSA
| | - Kazuhiro Shiozaki
- Division of Biological ScienceNara Institute of Science and TechnologyIkomaJapan
- Department of Microbiology and Molecular GeneticsUniversity of CaliforniaDavisCAUSA
| | - Christian Sell
- Department of PathologyDrexel University College of MedicinePhiladelphiaPAUSA
| | - Joshua Chang Mell
- Department of Microbiology and ImmunologyCenters for Genomics SciencesDrexel University College of MedicinePhiladelphiaPAUSA
| | - Eishi Noguchi
- Department of Biochemistry and Molecular BiologyDrexel University College of MedicinePhiladelphiaPAUSA
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Nagalingam K, Lorenc MT, Manoli S, Cameron SL, Clarke AR, Dudley KJ. Chromatin immunoprecipitation (ChIP) method for non-model fruit flies (Diptera: Tephritidae) and evidence of histone modifications. PLoS One 2018; 13:e0194420. [PMID: 29543899 PMCID: PMC5854383 DOI: 10.1371/journal.pone.0194420] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Accepted: 03/03/2018] [Indexed: 11/19/2022] Open
Abstract
Interactions between DNA and proteins located in the cell nucleus play an important role in controlling physiological processes by specifying, augmenting and regulating context-specific transcription events. Chromatin immunoprecipitation (ChIP) is a widely used methodology to study DNA-protein interactions and has been successfully used in various cell types for over three decades. More recently, by combining ChIP with genomic screening technologies and Next Generation Sequencing (e.g. ChIP-seq), it has become possible to profile DNA-protein interactions (including covalent histone modifications) across entire genomes. However, the applicability of ChIP-chip and ChIP-seq has rarely been extended to non-model species because of a number of technical challenges. Here we report a method that can be used to identify genome wide covalent histone modifications in a group of non-model fruit fly species (Diptera: Tephritidae). The method was developed by testing and refining protocols that have been used in model organisms, including Drosophila melanogaster. We demonstrate that this method is suitable for a group of economically important pest fruit fly species, viz., Bactrocera dorsalis, Ceratitis capitata, Zeugodacus cucurbitae and Bactrocera tryoni. We also report an example ChIP-seq dataset for B. tryoni, providing evidence for histone modifications in the genome of a tephritid fruit fly for the first time. Since tephritids are major agricultural pests globally, this methodology will be a valuable resource to study taxa-specific evolutionary questions and to assist with pest management. It also provides a basis for researchers working with other non-model species to undertake genome wide DNA-protein interaction studies.
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Affiliation(s)
- Kumaran Nagalingam
- School of Earth, Environmental and Biological Sciences, Queensland University of Technology (QUT), Brisbane, Qld, Australia
| | - Michał T. Lorenc
- School of Earth, Environmental and Biological Sciences, Queensland University of Technology (QUT), Brisbane, Qld, Australia
| | - Sahana Manoli
- School of Earth, Environmental and Biological Sciences, Queensland University of Technology (QUT), Brisbane, Qld, Australia
| | - Stephen L. Cameron
- School of Earth, Environmental and Biological Sciences, Queensland University of Technology (QUT), Brisbane, Qld, Australia
- Department of Entomology, Purdue University, West Lafayette, IN, United States of America
| | - Anthony R. Clarke
- School of Earth, Environmental and Biological Sciences, Queensland University of Technology (QUT), Brisbane, Qld, Australia
| | - Kevin J. Dudley
- School of Earth, Environmental and Biological Sciences, Queensland University of Technology (QUT), Brisbane, Qld, Australia
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Zhang J, Dai Q, Park D, Deng X. Targeting DNA Replication Stress for Cancer Therapy. Genes (Basel) 2016; 7:genes7080051. [PMID: 27548226 PMCID: PMC4999839 DOI: 10.3390/genes7080051] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 08/06/2016] [Accepted: 08/15/2016] [Indexed: 01/09/2023] Open
Abstract
The human cellular genome is under constant stress from extrinsic and intrinsic factors, which can lead to DNA damage and defective replication. In normal cells, DNA damage response (DDR) mediated by various checkpoints will either activate the DNA repair system or induce cellular apoptosis/senescence, therefore maintaining overall genomic integrity. Cancer cells, however, due to constitutive growth signaling and defective DDR, may exhibit “replication stress” —a phenomenon unique to cancer cells that is described as the perturbation of error-free DNA replication and slow-down of DNA synthesis. Although replication stress has been proven to induce genomic instability and tumorigenesis, recent studies have counterintuitively shown that enhancing replicative stress through further loosening of the remaining checkpoints in cancer cells to induce their catastrophic failure of proliferation may provide an alternative therapeutic approach. In this review, we discuss the rationale to enhance replicative stress in cancer cells, past approaches using traditional radiation and chemotherapy, and emerging approaches targeting the signaling cascades induced by DNA damage. We also summarize current clinical trials exploring these strategies and propose future research directions including the use of combination therapies, and the identification of potential new targets and biomarkers to track and predict treatment responses to targeting DNA replication stress.
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Affiliation(s)
- Jun Zhang
- Division of Hematology, Oncology and Blood & Marrow Transplantation, Department of Internal Medicine, Holden Comprehensive Cancer Center, University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, IA 52242, USA.
| | - Qun Dai
- Division of Hematology, Oncology and Blood & Marrow Transplantation, Department of Internal Medicine, Holden Comprehensive Cancer Center, University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, IA 52242, USA.
| | - Dongkyoo Park
- Division of Cancer Biology, Department of Radiation Oncology, Emory University School of Medicine and Winship Cancer Institute of Emory University, 1365C Clifton Road NE, Atlanta, GA 30322, USA.
| | - Xingming Deng
- Division of Cancer Biology, Department of Radiation Oncology, Emory University School of Medicine and Winship Cancer Institute of Emory University, 1365C Clifton Road NE, Atlanta, GA 30322, USA.
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Gadaleta MC, Das MM, Tanizawa H, Chang YT, Noma KI, Nakamura TM, Noguchi E. Swi1Timeless Prevents Repeat Instability at Fission Yeast Telomeres. PLoS Genet 2016; 12:e1005943. [PMID: 26990647 PMCID: PMC4798670 DOI: 10.1371/journal.pgen.1005943] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 02/25/2016] [Indexed: 01/09/2023] Open
Abstract
Genomic instability associated with DNA replication stress is linked to cancer and genetic pathologies in humans. If not properly regulated, replication stress, such as fork stalling and collapse, can be induced at natural replication impediments present throughout the genome. The fork protection complex (FPC) is thought to play a critical role in stabilizing stalled replication forks at several known replication barriers including eukaryotic rDNA genes and the fission yeast mating-type locus. However, little is known about the role of the FPC at other natural impediments including telomeres. Telomeres are considered to be difficult to replicate due to the presence of repetitive GT-rich sequences and telomere-binding proteins. However, the regulatory mechanism that ensures telomere replication is not fully understood. Here, we report the role of the fission yeast Swi1Timeless, a subunit of the FPC, in telomere replication. Loss of Swi1 causes telomere shortening in a telomerase-independent manner. Our epistasis analyses suggest that heterochromatin and telomere-binding proteins are not major impediments for telomere replication in the absence of Swi1. Instead, repetitive DNA sequences impair telomere integrity in swi1Δ mutant cells, leading to the loss of repeat DNA. In the absence of Swi1, telomere shortening is accompanied with an increased recruitment of Rad52 recombinase and more frequent amplification of telomere/subtelomeres, reminiscent of tumor cells that utilize the alternative lengthening of telomeres pathway (ALT) to maintain telomeres. These results suggest that Swi1 ensures telomere replication by suppressing recombination and repeat instability at telomeres. Our studies may also be relevant in understanding the potential role of Swi1Timeless in regulation of telomere stability in cancer cells. In every round of the cell cycle, cells must accurately replicate their full genetic information. This process is highly regulated, as defects during DNA replication cause genomic instability, leading to various genetic disorders including cancers. To thwart these problems, cells carry an array of complex mechanisms to deal with various obstacles found across the genome that can hamper DNA replication and cause DNA damage. Understanding how these mechanisms are regulated and orchestrated is of paramount importance in the field. In this report, we describe how Swi1, a Timeless-related protein in fission yeast, regulates efficient replication of telomeres, which are considered to be difficult to replicate due to the presence of repetitive DNA and telomere-binding proteins. We show that Swi1 prevents telomere damage and maintains telomere length by protecting integrity of telomeric repeats. Swi1-mediated telomere maintenance is independent of telomerase activity, and loss of Swi1 causes hyper-activation of recombination-based telomere maintenance, which generates heterogeneous telomeres. Similar telomerase-independent and recombination-dependent mechanism is utilized by approximately 15% of human cancers, linking telomere replication defects with cancer development. Thus, our study may be relevant in understanding the role of telomere replication defects in the development of cancers in humans.
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Affiliation(s)
- Mariana C. Gadaleta
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Mukund M. Das
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Hideki Tanizawa
- Gene Expression and Regulation Program, The Wistar Institute, Philadelphia, Pennsylvania, United States of America
| | - Ya-Ting Chang
- Department of Biochemistry and Molecular Genetics, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Ken-ichi Noma
- Gene Expression and Regulation Program, The Wistar Institute, Philadelphia, Pennsylvania, United States of America
| | - Toru M. Nakamura
- Department of Biochemistry and Molecular Genetics, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Eishi Noguchi
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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