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Du Z, Lin M, Li Q, Guo D, Xue Y, Liu W, Shi H, Chen T, Dan J. The totipotent 2C-like state safeguards genomic stability of mouse embryonic stem cells. J Cell Physiol 2024. [PMID: 38860420 DOI: 10.1002/jcp.31337] [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: 01/09/2024] [Revised: 05/17/2024] [Accepted: 05/28/2024] [Indexed: 06/12/2024]
Abstract
Mouse embryonic stem cells (mESCs) sporadically transition to a transient totipotent state that resembles blastomeres of the two-cell (2C) embryo stage, which has been proposed to contribute to exceptional genomic stability, one of the key features of mESCs. However, the biological significance of the rare population of 2C-like cells (2CLCs) in ESC cultures remains to be tested. Here we generated an inducible reporter cell system for specific elimination of 2CLCs from the ESC cultures to disrupt the equilibrium between ESCs and 2CLCs. We show that removing 2CLCs from the ESC cultures leads to dramatic accumulation of DNA damage, genomic mutations, and rearrangements, indicating impaired genomic instability. Furthermore, 2CLCs removal results in increased apoptosis and reduced proliferation of mESCs in both serum/LIF and 2i/LIF culture conditions. Unexpectedly, p53 deficiency results in defective response to DNA damage, leading to early accumulation of DNA damage, micronuclei, indicative of genomic instability, cell apoptosis, and reduced self-renewal capacity of ESCs when devoid of 2CLCs in cultures. Together, our data reveal that transition to the privileged 2C-like state is a major component of the intrinsic mechanisms that maintain the exceptional genomic stability of mESCs for long-term self-renewal.
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Affiliation(s)
- Zeling Du
- State Key Laboratory of Primate Biomedical Research, Kunming University of Science and Technology, Kunming, China
- Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, China
- Yunnan Key Laboratory of Primate Biomedical Research, Kunming, China
| | - Meiqi Lin
- State Key Laboratory of Primate Biomedical Research, Kunming University of Science and Technology, Kunming, China
- Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, China
- Yunnan Key Laboratory of Primate Biomedical Research, Kunming, China
| | - Qiaohua Li
- State Key Laboratory of Primate Biomedical Research, Kunming University of Science and Technology, Kunming, China
- Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, China
- Yunnan Key Laboratory of Primate Biomedical Research, Kunming, China
| | - Dan Guo
- State Key Laboratory of Primate Biomedical Research, Kunming University of Science and Technology, Kunming, China
- Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, China
- Yunnan Key Laboratory of Primate Biomedical Research, Kunming, China
| | - Yanna Xue
- State Key Laboratory of Primate Biomedical Research, Kunming University of Science and Technology, Kunming, China
- Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, China
- Yunnan Key Laboratory of Primate Biomedical Research, Kunming, China
| | - Wei Liu
- State Key Laboratory of Primate Biomedical Research, Kunming University of Science and Technology, Kunming, China
- Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, China
- Yunnan Key Laboratory of Primate Biomedical Research, Kunming, China
| | - Hong Shi
- State Key Laboratory of Primate Biomedical Research, Kunming University of Science and Technology, Kunming, China
- Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, China
- Yunnan Key Laboratory of Primate Biomedical Research, Kunming, China
| | - Taiping Chen
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- Programs in Genetics and Epigenetics, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, Texas, USA
| | - Jiameng Dan
- State Key Laboratory of Primate Biomedical Research, Kunming University of Science and Technology, Kunming, China
- Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, China
- Yunnan Key Laboratory of Primate Biomedical Research, Kunming, China
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2
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Fang M, Deibler SK, Nana AL, Vatsavayai SC, Banday S, Zhou Y, Almeida S, Weiss A, Brown RH, Seeley WW, Gao FB, Green MR. Loss of TDP-43 function contributes to genomic instability in amyotrophic lateral sclerosis. Front Neurosci 2023; 17:1251228. [PMID: 37849894 PMCID: PMC10577185 DOI: 10.3389/fnins.2023.1251228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Accepted: 09/08/2023] [Indexed: 10/19/2023] Open
Abstract
A common pathological hallmark of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) is the cytoplasmic mislocalization and aggregation of the DNA/RNA-binding protein TDP-43, but how loss of nuclear TDP-43 function contributes to ALS and FTD pathogenesis remains largely unknown. Here, using large-scale RNAi screening, we identify TARDBP, which encodes TDP-43, as a gene whose loss-of-function results in elevated DNA mutation rate and genomic instability. Consistent with this finding, we observe increased DNA damage in induced pluripotent stem cells (iPSCs) and iPSC-derived post-mitotic neurons generated from ALS patients harboring TARDBP mutations. We find that the increase in DNA damage in ALS iPSC-derived neurons is due to defects in two major pathways for DNA double-strand break repair: non-homologous end joining and homologous recombination. Cells with defects in DNA repair are sensitive to DNA damaging agents and, accordingly, we find that ALS iPSC-derived neurons show a marked reduction in survival following treatment with a DNA damaging agent. Importantly, we find that increased DNA damage is also observed in neurons with nuclear TDP-43 depletion from ALS/FTD patient brain tissues. Collectively, our results demonstrate that ALS neurons with loss of nuclear TDP-43 function have elevated levels of DNA damage and contribute to the idea that genomic instability is a defining pathological feature of ALS/FTD patients with TDP-43 pathology.
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Affiliation(s)
- Minggang Fang
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA, United States
| | - Sara K. Deibler
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA, United States
| | - Alissa L. Nana
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, San Francisco, CA, United States
| | - Sarat C. Vatsavayai
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, San Francisco, CA, United States
| | - Shahid Banday
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA, United States
| | - You Zhou
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA, United States
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA, United States
| | - Sandra Almeida
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA, United States
| | - Alexandra Weiss
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA, United States
| | - Robert H. Brown
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA, United States
| | - William W. Seeley
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, San Francisco, CA, United States
| | - Fen-Biao Gao
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA, United States
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA, United States
| | - Michael R. Green
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA, United States
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3
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Gökbuget D, Lenshoek K, Boileau RM, Bayerl J, Huang H, Wiita AP, Laird DJ, Blelloch R. Transcriptional repression upon S phase entry protects genome integrity in pluripotent cells. Nat Struct Mol Biol 2023; 30:1561-1570. [PMID: 37696959 DOI: 10.1038/s41594-023-01092-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 08/07/2023] [Indexed: 09/13/2023]
Abstract
Coincident transcription and DNA replication causes replication stress and genome instability. Rapidly dividing mouse pluripotent stem cells are highly transcriptionally active and experience elevated replication stress, yet paradoxically maintain genome integrity. Here, we study FOXD3, a transcriptional repressor enriched in pluripotent stem cells, and show that its repression of transcription upon S phase entry is critical to minimizing replication stress and preserving genome integrity. Acutely deleting Foxd3 leads to immediate replication stress, G2/M phase arrest, genome instability and p53-dependent apoptosis. FOXD3 binds near highly transcribed genes during S phase entry, and its loss increases the expression of these genes. Transient inhibition of RNA polymerase II in S phase reduces observed replication stress and cell cycle defects. Loss of FOXD3-interacting histone deacetylases induces replication stress, while transient inhibition of histone acetylation opposes it. These results show how a transcriptional repressor can play a central role in maintaining genome integrity through the transient inhibition of transcription during S phase, enabling faithful DNA replication.
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Affiliation(s)
- Deniz Gökbuget
- The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Center for Reproductive Sciences, University of California, San Francisco, San Francisco, CA, USA
- Department of Urology, University of California, San Francisco, San Francisco, CA, USA
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, USA
| | - Kayla Lenshoek
- The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Center for Reproductive Sciences, University of California, San Francisco, San Francisco, CA, USA
- Department of Urology, University of California, San Francisco, San Francisco, CA, USA
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, USA
| | - Ryan M Boileau
- The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Center for Reproductive Sciences, University of California, San Francisco, San Francisco, CA, USA
- Department of Urology, University of California, San Francisco, San Francisco, CA, USA
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, USA
| | - Jonathan Bayerl
- The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Center for Reproductive Sciences, University of California, San Francisco, San Francisco, CA, USA
- Department of Obstetrics, Gynecology and Reproductive Science, University of California, San Francisco, San Francisco, CA, USA
| | - Hector Huang
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, USA
- Department of Laboratory Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - Arun P Wiita
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, USA
- Department of Laboratory Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - Diana J Laird
- The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Center for Reproductive Sciences, University of California, San Francisco, San Francisco, CA, USA
- Department of Obstetrics, Gynecology and Reproductive Science, University of California, San Francisco, San Francisco, CA, USA
| | - Robert Blelloch
- The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Center for Reproductive Sciences, University of California, San Francisco, San Francisco, CA, USA.
- Department of Urology, University of California, San Francisco, San Francisco, CA, USA.
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, USA.
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4
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Saini P, Anugula S, Fong YW. The Role of ATP-Binding Cassette Proteins in Stem Cell Pluripotency. Biomedicines 2023; 11:1868. [PMID: 37509507 PMCID: PMC10377311 DOI: 10.3390/biomedicines11071868] [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: 05/17/2023] [Revised: 06/20/2023] [Accepted: 06/22/2023] [Indexed: 07/30/2023] Open
Abstract
Pluripotent stem cells (PSCs) are highly proliferative cells that can self-renew indefinitely in vitro. Upon receiving appropriate signals, PSCs undergo differentiation and can generate every cell type in the body. These unique properties of PSCs require specific gene expression patterns that define stem cell identity and dynamic regulation of intracellular metabolism to support cell growth and cell fate transitions. PSCs are prone to DNA damage due to elevated replicative and transcriptional stress. Therefore, mechanisms to prevent deleterious mutations in PSCs that compromise stem cell function or increase the risk of tumor formation from becoming amplified and propagated to progenitor cells are essential for embryonic development and for using PSCs including induced PSCs (iPSCs) as a cell source for regenerative medicine. In this review, we discuss the role of the ATP-binding cassette (ABC) superfamily in maintaining PSC homeostasis, and propose how their activities can influence cellular signaling and stem cell fate decisions. Finally, we highlight recent discoveries that not all ABC family members perform only canonical metabolite and peptide transport functions in PSCs; rather, they can participate in diverse cellular processes from genome surveillance to gene transcription and mRNA translation, which are likely to maintain the pristine state of PSCs.
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Affiliation(s)
- Prince Saini
- Brigham Regenerative Medicine Center, Brigham and Women’s Hospital, Boston, MA 02115, USA; (P.S.); (S.A.)
- Department of Medicine, Cardiovascular Medicine Division, Harvard Medical School, Boston, MA 02115, USA
- Harvard Stem Cell Institute, Cambridge, MA 02138, USA
| | - Sharath Anugula
- Brigham Regenerative Medicine Center, Brigham and Women’s Hospital, Boston, MA 02115, USA; (P.S.); (S.A.)
- Department of Medicine, Cardiovascular Medicine Division, Harvard Medical School, Boston, MA 02115, USA
- Harvard Stem Cell Institute, Cambridge, MA 02138, USA
| | - Yick W. Fong
- Brigham Regenerative Medicine Center, Brigham and Women’s Hospital, Boston, MA 02115, USA; (P.S.); (S.A.)
- Department of Medicine, Cardiovascular Medicine Division, Harvard Medical School, Boston, MA 02115, USA
- Harvard Stem Cell Institute, Cambridge, MA 02138, USA
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5
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Pallaseni A, Peets EM, Girling G, Crepaldi L, Kuzmin I, Raudvere U, Peterson H, Serçin Ö, Mardin BR, Kosicki M, Parts L. The interplay of DNA repair context with target sequence predictably biasses Cas9-generated mutations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.28.546891. [PMID: 37425722 PMCID: PMC10326969 DOI: 10.1101/2023.06.28.546891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
The genome engineering capability of the CRISPR/Cas system depends on the DNA repair machinery to generate the final outcome. Several genes can have an impact on mutations created, but their exact function and contribution to the result of the repair are not completely characterised. This lack of knowledge has limited the ability to comprehend and regulate the editing outcomes. Here, we measure how the absence of 21 repair genes changes the mutation outcomes of Cas9-generated cuts at 2,812 synthetic target sequences in mouse embryonic stem cells. Absence of key non-homologous end joining genes Lig4, Xrcc4, and Xlf abolished small insertions and deletions, while disabling key microhomology-mediated repair genes Nbn and Polq reduced frequency of longer deletions. Complex alleles of combined insertion and deletions were preferentially generated in the absence of Xrcc6. We further discover finer structure in the outcome frequency changes for single nucleotide insertions and deletions between large microhomologies that are differentially modulated by the knockouts. We use the knowledge of the reproducible variation across repair milieus to build predictive models of Cas9 editing results that outperform the current standards. This work improves our understanding of DNA repair gene function, and provides avenues for more precise modulation of CRISPR/Cas9-generated mutations.
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Affiliation(s)
- Ananth Pallaseni
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
| | - Elin Madli Peets
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
| | - Gareth Girling
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
| | - Luca Crepaldi
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
| | - Ivan Kuzmin
- Department of Computer Science, University of Tartu, Tartu, Estonia
| | - Uku Raudvere
- Department of Computer Science, University of Tartu, Tartu, Estonia
| | - Hedi Peterson
- Department of Computer Science, University of Tartu, Tartu, Estonia
| | - Özdemirhan Serçin
- BioMed X Institute (GmbH), Im Neuenheimer Feld 515, Heidelberg, Germany
| | - Balca R. Mardin
- BioMed X Institute (GmbH), Im Neuenheimer Feld 515, Heidelberg, Germany
| | - Michael Kosicki
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
- Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Leopold Parts
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
- Department of Computer Science, University of Tartu, Tartu, Estonia
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6
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Gong D, Wang L, Zhou H, Gao J, Zhang W, Zheng P. Long noncoding RNA Lnc530 localizes on R-loops and regulates R-loop formation and genomic stability in mouse embryonic stem cells. Stem Cell Reports 2023; 18:952-968. [PMID: 36931280 PMCID: PMC10147553 DOI: 10.1016/j.stemcr.2023.02.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 02/13/2023] [Accepted: 02/13/2023] [Indexed: 03/18/2023] Open
Abstract
Embryonic stem cells (ESCs) are superior to differentiated cells to maintain genome stability, but the underlying mechanisms remain largely elusive. R-loops are constantly formed during transcription and are inducers of DNA damage if not resolved. Here we report that mouse ESCs (mESCs) can efficiently prevent unscheduled R-loop formation, and a long noncoding RNA Lnc530 plays regulatory role. Lnc530 is expressed in mESCs and localizes on R-loops. Depletion of Lnc530 in mESCs causes R-loop accumulation and DNA damage, whereas forced expression of Lnc530 in differentiated cells suppresses the R-loop formation. Mechanistically, Lnc530 associates with DDX5 and TDP-43 in an inter-dependent manner on R-loops. Formation of Lnc530-DDX5-TDP-43 complex substantially increases the local protein levels of DDX5 and TDP-43, both of which play critical roles in R-loop regulation. This study uncovers an efficient strategy to prevent R-loop accumulation and preserve genomic stability in mESCs and possibly other stem cell types.
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Affiliation(s)
- Daohua Gong
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650203, China; University of Chinese Academy of Sciences, Beijing 101408, China; Key Laboratory of Animal Models and Human Disease Mechanisms of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650203, China
| | - Lin Wang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650203, China; Key Laboratory of Animal Models and Human Disease Mechanisms of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650203, China
| | - Hu Zhou
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Jing Gao
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Weidao Zhang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650203, China; Key Laboratory of Animal Models and Human Disease Mechanisms of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650203, China
| | - Ping Zheng
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650203, China; KIZ/CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650203, China; Key Laboratory of Animal Models and Human Disease Mechanisms of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650203, China.
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7
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Gillespie MS, Ward CM, Davies CC. DNA Repair and Therapeutic Strategies in Cancer Stem Cells. Cancers (Basel) 2023; 15:1897. [PMID: 36980782 PMCID: PMC10047301 DOI: 10.3390/cancers15061897] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 03/18/2023] [Accepted: 03/20/2023] [Indexed: 03/30/2023] Open
Abstract
First-line cancer treatments successfully eradicate the differentiated tumour mass but are comparatively ineffective against cancer stem cells (CSCs), a self-renewing subpopulation thought to be responsible for tumour initiation, metastasis, heterogeneity, and recurrence. CSCs are thus presented as the principal target for elimination during cancer treatment. However, CSCs are challenging to drug target because of numerous intrinsic and extrinsic mechanisms of drug resistance. One such mechanism that remains relatively understudied is the DNA damage response (DDR). CSCs are presumed to possess properties that enable enhanced DNA repair efficiency relative to their highly proliferative bulk progeny, facilitating improved repair of double-strand breaks induced by radiotherapy and most chemotherapeutics. This can occur through multiple mechanisms, including increased expression and splicing fidelity of DNA repair genes, robust activation of cell cycle checkpoints, and elevated homologous recombination-mediated DNA repair. Herein, we summarise the current knowledge concerning improved genome integrity in non-transformed stem cells and CSCs, discuss therapeutic opportunities within the DDR for re-sensitising CSCs to genotoxic stressors, and consider the challenges posed regarding unbiased identification of novel DDR-directed strategies in CSCs. A better understanding of the DDR mediating chemo/radioresistance mechanisms in CSCs could lead to novel therapeutic approaches, thereby enhancing treatment efficacy in cancer patients.
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Affiliation(s)
- Matthew S. Gillespie
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK; (M.S.G.)
- School of Cancer Sciences, University of Southampton, Southampton SO16 6YD, UK
| | - Ciara M. Ward
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK; (M.S.G.)
| | - Clare C. Davies
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK; (M.S.G.)
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8
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Tichy ED. Specialized Circuitry of Embryonic Stem Cells Promotes Genomic Integrity. Crit Rev Oncog 2023; 27:1-15. [PMID: 36734869 DOI: 10.1615/critrevoncog.2022042332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Embryonic stem cells (ESCs) give rise to all cell types of the organism. Given the importance of these cells in this process, ESCs must employ robust mechanisms to protect genomic integrity or risk catastrophic propagation of mutations throughout the organism. Should such an event occur in daughter cells that will eventually contribute to the germline, the overall species health could dramatically decline. This review describes several key mechanisms employed by ESCs that are unique to these cells, in order to maintain their genomic integrity. Additionally, the contributions of cell cycle regulators in modulating ESC differentiation, after DNA damage exposure, are also examined. Where data are available, findings reported in ESCs are extended to include observations described in induced pluripotent stem cells (IPSCs).
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Affiliation(s)
- Elisia D Tichy
- Department of Orthopaedic Surgery, Perelman School of Medicine, The University of Pennsylvania, 371 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104-6081
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9
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Cheng C, Fei Z, Xiao P. Methods to improve the accuracy of next-generation sequencing. Front Bioeng Biotechnol 2023; 11:982111. [PMID: 36741756 PMCID: PMC9895957 DOI: 10.3389/fbioe.2023.982111] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 01/11/2023] [Indexed: 01/21/2023] Open
Abstract
Next-generation sequencing (NGS) is present in all fields of life science, which has greatly promoted the development of basic research while being gradually applied in clinical diagnosis. However, the cost and throughput advantages of next-generation sequencing are offset by large tradeoffs with respect to read length and accuracy. Specifically, its high error rate makes it extremely difficult to detect SNPs or low-abundance mutations, limiting its clinical applications, such as pharmacogenomics studies primarily based on SNP and early clinical diagnosis primarily based on low abundance mutations. Currently, Sanger sequencing is still considered to be the gold standard due to its high accuracy, so the results of next-generation sequencing require verification by Sanger sequencing in clinical practice. In order to maintain high quality next-generation sequencing data, a variety of improvements at the levels of template preparation, sequencing strategy and data processing have been developed. This study summarized the general procedures of next-generation sequencing platforms, highlighting the improvements involved in eliminating errors at each step. Furthermore, the challenges and future development of next-generation sequencing in clinical application was discussed.
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10
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Zhao Q, Liu K, Zhang L, Li Z, Wang L, Cao J, Xu Y, Zheng A, Chen Q, Zhao T. BNIP3-dependent mitophagy safeguards ESC genomic integrity via preventing oxidative stress-induced DNA damage and protecting homologous recombination. Cell Death Dis 2022; 13:976. [PMID: 36402748 PMCID: PMC9675825 DOI: 10.1038/s41419-022-05413-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 11/03/2022] [Accepted: 11/07/2022] [Indexed: 11/21/2022]
Abstract
Embryonic stem cells (ESCs) have a significantly lower mutation load compared to somatic cells, but the mechanisms that guard genomic integrity in ESCs remain largely unknown. Here we show that BNIP3-dependent mitophagy protects genomic integrity in mouse ESCs. Deletion of Bnip3 increases cellular reactive oxygen species (ROS) and decreases ATP generation. Increased ROS in Bnip3-/- ESCs compromised self-renewal and were partially rescued by either NAC treatment or p53 depletion. The decreased cellular ATP in Bnip3-/- ESCs induced AMPK activation and deteriorated homologous recombination, leading to elevated mutation load during long-term propagation. Whereas activation of AMPK in X-ray-treated Bnip3+/+ ESCs dramatically ascended mutation rates, inactivation of AMPK in Bnip3-/- ESCs under X-ray stress remarkably decreased the mutation load. In addition, enhancement of BNIP3-dependent mitophagy during reprogramming markedly decreased mutation accumulation in established iPSCs. In conclusion, we demonstrated a novel pathway in which BNIP3-dependent mitophagy safeguards ESC genomic stability, and that could potentially be targeted to improve pluripotent stem cell genomic integrity for regenerative medicine.
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Affiliation(s)
- Qian Zhao
- grid.9227.e0000000119573309State Key Laboratory of Stem Cell and Reproductive Biology, Institute for Stem Cell and Regeneration, Institute of Zoology, Chinese Academy of Sciences Beijing, Beijing, 100101 China ,grid.512959.3Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, 100101 China
| | - Kun Liu
- grid.9227.e0000000119573309State Key Laboratory of Stem Cell and Reproductive Biology, Institute for Stem Cell and Regeneration, Institute of Zoology, Chinese Academy of Sciences Beijing, Beijing, 100101 China ,grid.512959.3Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, 100101 China
| | - Lin Zhang
- grid.9227.e0000000119573309State Key Laboratory of Stem Cell and Reproductive Biology, Institute for Stem Cell and Regeneration, Institute of Zoology, Chinese Academy of Sciences Beijing, Beijing, 100101 China ,grid.410726.60000 0004 1797 8419University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Zheng Li
- grid.24696.3f0000 0004 0369 153XDepartment of Gastroenterology, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070 China
| | - Liang Wang
- grid.9227.e0000000119573309State Key Laboratory of Stem Cell and Reproductive Biology, Institute for Stem Cell and Regeneration, Institute of Zoology, Chinese Academy of Sciences Beijing, Beijing, 100101 China ,grid.410726.60000 0004 1797 8419University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Jiani Cao
- grid.9227.e0000000119573309State Key Laboratory of Stem Cell and Reproductive Biology, Institute for Stem Cell and Regeneration, Institute of Zoology, Chinese Academy of Sciences Beijing, Beijing, 100101 China ,grid.512959.3Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, 100101 China
| | - Youqing Xu
- grid.24696.3f0000 0004 0369 153XDepartment of Gastroenterology, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070 China
| | - Aihua Zheng
- grid.9227.e0000000119573309State Key Laboratory of Stem Cell and Reproductive Biology, Institute for Stem Cell and Regeneration, Institute of Zoology, Chinese Academy of Sciences Beijing, Beijing, 100101 China ,grid.410726.60000 0004 1797 8419University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Quan Chen
- grid.216938.70000 0000 9878 7032College of Life Sciences, Nankai University, Tianjin, 300073 China
| | - Tongbiao Zhao
- grid.9227.e0000000119573309State Key Laboratory of Stem Cell and Reproductive Biology, Institute for Stem Cell and Regeneration, Institute of Zoology, Chinese Academy of Sciences Beijing, Beijing, 100101 China ,grid.512959.3Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, 100101 China ,grid.410726.60000 0004 1797 8419University of Chinese Academy of Sciences, Beijing, 100049 China
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11
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Ayaz G, Yan H, Malik N, Huang J. An Updated View of the Roles of p53 in Embryonic Stem Cells. Stem Cells 2022; 40:883-891. [PMID: 35904997 PMCID: PMC9585900 DOI: 10.1093/stmcls/sxac051] [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: 01/26/2022] [Accepted: 07/14/2022] [Indexed: 11/12/2022]
Abstract
The TP53 gene is unarguably one of the most studied human genes. Its encoded protein, p53, is a tumor suppressor and is often called the "guardian of the genome" due to its pivotal role in maintaining genome stability. Historically, most studies of p53 have focused on its roles in somatic cells and tissues, but in the last two decades, its functions in embryonic stem cells (ESCs) and induced pluripotent stem cells have attracted increasing attention. Recent studies have identified p53 as a critical regulator of pluripotency, self-renewal, differentiation, proliferation, and genome stability in mouse and human embryonic stem cells. In this article, we systematically review the studies on the functions of p53 in ESCs, provide an updated overview, attempt to reconcile controversial results described in the literature, and discuss the relevance of these cellular functions of p53 to its roles in tumor suppression.
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Affiliation(s)
- Gamze Ayaz
- Cancer and Stem Cell Epigenetics, Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Hualong Yan
- Cancer and Stem Cell Epigenetics, Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Navdeep Malik
- Cancer and Stem Cell Epigenetics, Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jing Huang
- Cancer and Stem Cell Epigenetics, Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
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12
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3R measures in facilities for the production of genetically modified rodents. Lab Anim (NY) 2022; 51:162-177. [PMID: 35641635 DOI: 10.1038/s41684-022-00978-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 04/22/2022] [Indexed: 12/30/2022]
Abstract
Sociocultural changes in the human-animal relationship have led to increasing demands for animal welfare in biomedical research. The 3R concept is the basis for bringing this demand into practice: Replace animal experiments with alternatives where possible, Reduce the number of animals used to a scientifically justified minimum and Refine the procedure to minimize animal harm. The generation of gene-modified sentient animals such as mice and rats involves many steps that include various forms of manipulation. So far, no coherent analysis of the application of the 3Rs to gene manipulation has been performed. Here we provide guidelines from the Committee on Genetics and Breeding of Laboratory Animals of the German Society for Laboratory Animal Science to implement the 3Rs in every step during the generation of genetically modified animals. We provide recommendations for applying the 3Rs as well as success/intervention parameters for each step of the process, from experiment planning to choice of technology, harm-benefit analysis, husbandry conditions, management of genetically modified lines and actual procedures. We also discuss future challenges for animal welfare in the context of developing technologies. Taken together, we expect that our comprehensive analysis and our recommendations for the appropriate implementation of the 3Rs to technologies for genetic modifications of rodents will benefit scientists from a wide range of disciplines and will help to improve the welfare of a large number of laboratory animals worldwide.
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13
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The Chromatin Architectural Protein CTCF Is Critical for Cell Survival upon Irradiation-Induced DNA Damage. Int J Mol Sci 2022; 23:ijms23073896. [PMID: 35409255 PMCID: PMC8999573 DOI: 10.3390/ijms23073896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 03/26/2022] [Accepted: 03/29/2022] [Indexed: 02/05/2023] Open
Abstract
CTCF is a nuclear protein initially discovered for its role in enhancer-promoter insulation. It has been shown to play a role in genome architecture and in fact, its DNA binding sites are enriched at the borders of chromatin domains. Recently, we showed that depletion of CTCF impairs the DNA damage response to ionizing radiation. To investigate the relationship between chromatin domains and DNA damage repair, we present here clonogenic survival assays in different cell lines upon CTCF knockdown and ionizing irradiation. The application of a wide range of ionizing irradiation doses (0–10 Gy) allowed us to investigate the survival response through a biophysical model that accounts for the double-strand breaks’ probability distribution onto chromatin domains. We demonstrate that the radiosensitivity of different cell lines is increased upon lowering the amount of the architectural protein. Our model shows that the deficiency in the DNA repair ability is related to the changes in the size of chromatin domains that occur when different amounts of CTCF are present in the nucleus.
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14
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Lewis MA, Ingham NJ, Chen J, Pearson S, Di Domenico F, Rekhi S, Allen R, Drake M, Willaert A, Rook V, Pass J, Keane T, Adams DJ, Tucker AS, White JK, Steel KP. Identification and characterisation of spontaneous mutations causing deafness from a targeted knockout programme. BMC Biol 2022; 20:67. [PMID: 35296311 PMCID: PMC8928630 DOI: 10.1186/s12915-022-01257-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 02/17/2022] [Indexed: 11/30/2022] Open
Abstract
Background Mice carrying targeted mutations are important for investigating gene function and the role of genes in disease, but off-target mutagenic effects associated with the processes of generating targeted alleles, for instance using Crispr, and culturing embryonic stem cells, offer opportunities for spontaneous mutations to arise. Identifying spontaneous mutations relies on the detection of phenotypes segregating independently of targeted alleles, and having a broad estimate of the level of mutations generated by intensive breeding programmes is difficult given that many phenotypes are easy to miss if not specifically looked for. Here we present data from a large, targeted knockout programme in which mice were analysed through a phenotyping pipeline. Such spontaneous mutations segregating within mutant lines may confound phenotypic analyses, highlighting the importance of record-keeping and maintaining correct pedigrees. Results Twenty-five lines out of 1311 displayed different deafness phenotypes that did not segregate with the targeted allele. We observed a variety of phenotypes by Auditory Brainstem Response (ABR) and behavioural assessment and isolated eight lines showing early-onset severe progressive hearing loss, later-onset progressive hearing loss, low frequency hearing loss, or complete deafness, with vestibular dysfunction. The causative mutations identified include deletions, insertions, and point mutations, some of which involve new genes not previously associated with deafness while others are new alleles of genes known to underlie hearing loss. Two of the latter show a phenotype much reduced in severity compared to other mutant alleles of the same gene. We investigated the ES cells from which these lines were derived and determined that only one of the 8 mutations could have arisen in the ES cell, and in that case, only after targeting. Instead, most of the non-segregating mutations appear to have occurred during breeding of mutant mice. In one case, the mutation arose within the wildtype colony used for expanding mutant lines. Conclusions Our data show that spontaneous mutations with observable effects on phenotype are a common side effect of intensive breeding programmes, including those underlying targeted mutation programmes. Such spontaneous mutations segregating within mutant lines may confound phenotypic analyses, highlighting the importance of record-keeping and maintaining correct pedigrees. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-022-01257-8.
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Affiliation(s)
- Morag A Lewis
- Wolfson Centre for Age-Related Diseases, King's College London, London, SE1 1UL, England. .,Wellcome Sanger Institute, Hinxton, CB10 1SA, England.
| | - Neil J Ingham
- Wolfson Centre for Age-Related Diseases, King's College London, London, SE1 1UL, England.,Wellcome Sanger Institute, Hinxton, CB10 1SA, England
| | - Jing Chen
- Wolfson Centre for Age-Related Diseases, King's College London, London, SE1 1UL, England.,Wellcome Sanger Institute, Hinxton, CB10 1SA, England
| | | | - Francesca Di Domenico
- Wolfson Centre for Age-Related Diseases, King's College London, London, SE1 1UL, England
| | - Sohinder Rekhi
- Wolfson Centre for Age-Related Diseases, King's College London, London, SE1 1UL, England
| | - Rochelle Allen
- Wolfson Centre for Age-Related Diseases, King's College London, London, SE1 1UL, England
| | - Matthew Drake
- Wolfson Centre for Age-Related Diseases, King's College London, London, SE1 1UL, England
| | - Annelore Willaert
- Research Group of Experimental Oto-Rhino-Laryngology, Department of Neurosciences, KU Leuven - University of Leuven, Leuven, Belgium
| | - Victoria Rook
- Wolfson Centre for Age-Related Diseases, King's College London, London, SE1 1UL, England
| | - Johanna Pass
- Wolfson Centre for Age-Related Diseases, King's College London, London, SE1 1UL, England.,Wellcome Sanger Institute, Hinxton, CB10 1SA, England
| | - Thomas Keane
- Wellcome Sanger Institute, Hinxton, CB10 1SA, England
| | - David J Adams
- Wellcome Sanger Institute, Hinxton, CB10 1SA, England
| | - Abigail S Tucker
- Centre for Craniofacial and Regenerative Biology, King's College London, London, SE1 9RT, England
| | | | - Karen P Steel
- Wolfson Centre for Age-Related Diseases, King's College London, London, SE1 1UL, England.,Wellcome Sanger Institute, Hinxton, CB10 1SA, England
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15
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Zhang Q, Zhao L, Yang Y, Li S, Liu Y, Chen C. Mosaic loss of chromosome Y promotes leukemogenesis and clonal hematopoiesis. JCI Insight 2022; 7:153768. [PMID: 35132955 PMCID: PMC8855789 DOI: 10.1172/jci.insight.153768] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 12/23/2021] [Indexed: 12/21/2022] Open
Abstract
Mosaic loss of chromosome Y (mLOY) in blood cells is one of the most frequent chromosome alterations in adult males. It is strongly associated with clonal hematopoiesis, hematopoietic malignancies, and other hematopoietic and nonhematopoietic diseases. However, whether there is a causal relationship between mLOY and human diseases is unknown. Here, we generated mLOY in murine hematopoietic stem and progenitor cells (HSPCs) with CRISPR/Cas9 genome editing. We found that mLOY led to dramatically increased DNA damage in HSPCs. Interestingly, HSPCs with mLOY displayed significantly enhanced reconstitution capacity and gave rise to clonal hematopoiesis in vivo. mLOY, which is associated with AML1-ETO translocation and p53 defects in patients with acute myeloid leukemia (AML), promoted AML in mice. Mechanistically, loss of KDM5D, a chromosome Y-specific histone 3 lysine 4 demethylase in both humans and mice, partially recapitulated mLOY in DNA damage and leukemogenesis. Thus, our study validates mLOY as a functional driver for clonal hematopoiesis and leukemogenesis.
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MESH Headings
- Animals
- Carcinogenesis/genetics
- Chromosomes, Human, Y/genetics
- Clonal Hematopoiesis/genetics
- Core Binding Factor Alpha 2 Subunit/genetics
- Core Binding Factor Alpha 2 Subunit/metabolism
- Gene Editing
- Hematopoietic Stem Cells/metabolism
- Hematopoietic Stem Cells/pathology
- Humans
- Leukemia, Myeloid, Acute/genetics
- Leukemia, Myeloid, Acute/metabolism
- Leukemia, Myeloid, Acute/pathology
- Male
- Mice
- Mice, Transgenic
- Models, Animal
- Mutation
- Neoplasms, Experimental
- Translocation, Genetic
- Tumor Cells, Cultured
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16
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Xin Y, Wang J, Wu Y, Li Q, Dong M, Liu C, He Q, Wang R, Wang D, Jiang S, Xiao W, Tian Y, Zhang W. Identification of Nanog as a novel inhibitor of Rad51. Cell Death Dis 2022; 13:193. [PMID: 35220392 PMCID: PMC8882189 DOI: 10.1038/s41419-022-04644-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 01/12/2022] [Accepted: 02/01/2022] [Indexed: 11/09/2022]
Abstract
AbstractTo develop inhibitors targeting DNA damage repair pathways is important to improve the effectiveness of chemo- and radiotherapy for cancer patients. Rad51 mediates homologous recombination (HR) repair of DNA damages. It is widely overexpressed in human cancers and overwhelms chemo- and radiotherapy-generated DNA damages through enhancing HR repair signaling, preventing damage-caused cancer cell death. Therefore, to identify inhibitors of Rad51 is important to achieve effective treatment of cancers. Transcription factor Nanog is a core regulator of embryonic stem (ES) cells for its indispensable role in stemness maintenance. In this study, we identified Nanog as a novel inhibitor of Rad51. It interacts with Rad51 and inhibits Rad51-mediated HR repair of DNA damage through its C/CD2 domain. Moreover, Rad51 inhibition can be achieved by nanoscale material- or cell-penetrating peptide (CPP)-mediated direct delivery of Nanog-C/CD2 peptides into somatic cancer cells. Furthermore, we revealed that Nanog suppresses the binding of Rad51 to single-stranded DNAs to stall the HR repair signaling. This study provides explanation for the high γH2AX level in unperturbed ES cells and early embryos, and suggests Nanog-C/CD2 as a promising drug candidate applied to Rad51-related basic research and therapeutic application studies.
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17
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Genomic stability of mouse spermatogonial stem cells in vitro. Sci Rep 2021; 11:24199. [PMID: 34921203 PMCID: PMC8683475 DOI: 10.1038/s41598-021-03658-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 12/08/2021] [Indexed: 11/08/2022] Open
Abstract
Germline mutations underlie genetic diversity and species evolution. Previous studies have assessed the theoretical mutation rates and spectra in germ cells mostly by analyzing genetic markers and reporter genes in populations and pedigrees. This study reported the direct measurement of germline mutations by whole-genome sequencing of cultured spermatogonial stem cells in mice, namely germline stem (GS) cells, together with multipotent GS (mGS) cells that spontaneously dedifferentiated from GS cells. GS cells produce functional sperm that can generate offspring by transplantation into seminiferous tubules, whereas mGS cells contribute to germline chimeras by microinjection into blastocysts in a manner similar to embryonic stem cells. The estimated mutation rate of GS and mGS cells was approximately 0.22 × 10-9 and 1.0 × 10-9 per base per cell population doubling, respectively, indicating that GS cells have a lower mutation rate compared to mGS cells. GS and mGS cells also showed distinct mutation patterns, with C-to-T transition as the most frequent in GS cells and C-to-A transversion as the most predominant in mGS cells. By karyotype analysis, GS cells showed recurrent trisomy of chromosomes 15 and 16, whereas mGS cells frequently exhibited chromosomes 1, 6, 8, and 11 amplifications, suggesting that distinct chromosomal abnormalities confer a selective growth advantage for each cell type in vitro. These data provide the basis for studying germline mutations and a foundation for the future utilization of GS cells for reproductive technology and clinical applications.
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18
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Lawing AM, McCoy M, Reinke BA, Sarkar SK, Smith FA, Wright D. A Framework for Investigating Rules of Life by Establishing Zones of Influence. Integr Comp Biol 2021; 61:2095-2108. [PMID: 34297089 DOI: 10.1093/icb/icab169] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 06/26/2021] [Accepted: 07/20/2021] [Indexed: 12/18/2022] Open
Abstract
The incredible complexity of biological processes across temporal and spatial scales hampers defining common underlying mechanisms driving the patterns of life. However, recent advances in sequencing, big data analysis, machine learning, and molecular dynamics simulation have renewed the hope and urgency of finding potential hidden rules of life. There currently exists no framework to develop such synoptic investigations. Some efforts aim to identify unifying rules of life across hierarchical levels of time, space, and biological organization, but not all phenomena occur across all the levels of these hierarchies. Instead of identifying the same parameters and rules across levels, we posit that each level of a temporal and spatial scale and each level of biological organization has unique parameters and rules that may or may not predict outcomes in neighboring levels. We define this neighborhood, or the set of levels, across which a rule functions as the zone of influence. Here, we introduce the zone of influence framework and explain using three examples: (Smocovitis, 1992) randomness in biology, where we use a Poisson process to describe processes from protein dynamics to DNA mutations to gene expressions, (Leroi, 2014) island biogeography, and (Gropp, 2016) animal coloration. The zone of influence framework may enable researchers to identify which levels are worth investigating for a particular phenomenon and reframe the narrative of searching for a unifying rule of life to the investigation of how, when, and where various rules of life operate.
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Affiliation(s)
| | - Michael McCoy
- Department of Biology, East Carolina University, NC, USA
| | - Beth A Reinke
- Department of Biology, Northeastern Illinois University, IL, USA
| | | | - Felisa A Smith
- Department of Biology, University of New Mexico, NM, USA
| | - Derek Wright
- Department of Physics, Colorado School of Mines, CO, USA
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19
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Vijg J. From DNA damage to mutations: All roads lead to aging. Ageing Res Rev 2021; 68:101316. [PMID: 33711511 PMCID: PMC10018438 DOI: 10.1016/j.arr.2021.101316] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 02/26/2021] [Accepted: 03/03/2021] [Indexed: 12/20/2022]
Abstract
Damage to the repository of genetic information in cells has plagued life since its very beginning 3-4 billion years ago. Initially, in the absence of an ozone layer, especially damage from solar UV radiation must have been frequent, with other sources, most notably endogenous sources related to cell metabolism, gaining in importance over time. To cope with this high frequency of damage to the increasingly long DNA molecules that came to encode the growing complexity of cellular functions in cells, DNA repair evolved as one of the earliest genetic traits. Then as now, errors during the repair of DNA damage generated mutations, which provide the substrate for evolution by natural selection. With the emergence of multicellular organisms also the soma became a target of DNA damage and mutations. In somatic cells selection against the adverse effects of DNA damage is greatly diminished, especially in postmitotic cells after the age of first reproduction. Based on an abundance of evidence, DNA damage is now considered as the single most important driver of the degenerative processes that collectively cause aging. Here I will first briefly review the evidence for DNA damage as a cause of aging since the beginning of life. Then, after discussing the possible direct adverse effects of DNA damage and its cellular responses, I will provide an overview of the considerable progress that has recently been made in analyzing a major consequence of DNA damage in humans and other complex organisms: somatic mutations and the resulting genome mosaicism. Recent advances in studying somatic mutagenesis and genome mosaicism in different human and animal tissues will be discussed with a focus on the possible mechanisms through which loss of DNA sequence integrity could cause age-related functional decline and disease.
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Affiliation(s)
- Jan Vijg
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, USA; Center for Single-Cell Omics, School of Public Health, Shanghai Jiao Tong University, School of Medicine, Shanghai, China.
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20
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Blakemore D, Vilaplana-Lopera N, Almaghrabi R, Gonzalez E, Moya M, Ward C, Murphy G, Gambus A, Petermann E, Stewart GS, García P. MYBL2 and ATM suppress replication stress in pluripotent stem cells. EMBO Rep 2021; 22:e51120. [PMID: 33779025 PMCID: PMC8097389 DOI: 10.15252/embr.202051120] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 02/10/2021] [Accepted: 02/19/2021] [Indexed: 12/30/2022] Open
Abstract
Replication stress, a major cause of genome instability in cycling cells, is mainly prevented by the ATR-dependent replication stress response pathway in somatic cells. However, the replication stress response pathway in embryonic stem cells (ESCs) may be different due to alterations in cell cycle phase length. The transcription factor MYBL2, which is implicated in cell cycle regulation, is expressed a hundred to a thousand-fold more in ESCs compared with somatic cells. Here we show that MYBL2 activates ATM and suppresses replication stress in ESCs. Consequently, loss of MYBL2 or inhibition of ATM or Mre11 in ESCs results in replication fork slowing, increased fork stalling and elevated origin firing. Additionally, we demonstrate that inhibition of CDC7 activity rescues replication stress induced by MYBL2 loss and ATM inhibition, suggesting that uncontrolled new origin firing may underlie the replication stress phenotype resulting from loss/inhibition of MYBL2 and ATM. Overall, our study proposes that in addition to ATR, a MYBL2-MRN-ATM replication stress response pathway functions in ESCs to control DNA replication initiation and prevent genome instability.
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Affiliation(s)
- Daniel Blakemore
- Institute of Cancer and Genomic Science, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Nuria Vilaplana-Lopera
- Institute of Cancer and Genomic Science, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Ruba Almaghrabi
- Institute of Cancer and Genomic Science, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Elena Gonzalez
- Institute of Cancer and Genomic Science, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Miriam Moya
- Institute of Cancer and Genomic Science, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Carl Ward
- Laboratory of Integrative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences (CAS), Guangzhou, China.,Chinese Academy of Sciences (CAS), Key Laboratory of Regenerative Biology and Guangdong Provincial Key Laboratory of Stem Cell and regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Guangzhou, China
| | - George Murphy
- Department of Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Agnieszka Gambus
- Institute of Cancer and Genomic Science, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Eva Petermann
- Institute of Cancer and Genomic Science, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Grant S Stewart
- Institute of Cancer and Genomic Science, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Paloma García
- Institute of Cancer and Genomic Science, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
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21
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Bloom JC, Schimenti JC. Sexually dimorphic DNA damage responses and mutation avoidance in the mouse germline. Genes Dev 2020; 34:1637-1649. [PMID: 33184219 PMCID: PMC7706705 DOI: 10.1101/gad.341602.120] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 10/07/2020] [Indexed: 12/20/2022]
Abstract
In this study, Bloom and Schimenti examine the response of primordial germ cells to DNA damage. Using both environmental and genetic stresses, the authors reveal the importance of the G1 checkpoint in preventing accumulation of complex mutations in the germline, and the differentiation of the DNA damage response during germ cell development. Germ cells specified during fetal development form the foundation of the mammalian germline. These primordial germ cells (PGCs) undergo rapid proliferation, yet the germline is highly refractory to mutation accumulation compared with somatic cells. Importantly, while the presence of endogenous or exogenous DNA damage has the potential to impact PGCs, there is little known about how these cells respond to stressors. To better understand the DNA damage response (DDR) in these cells, we exposed pregnant mice to ionizing radiation (IR) at specific gestational time points and assessed the DDR in PGCs. Our results show that PGCs prior to sex determination lack a G1 cell cycle checkpoint. Additionally, the response to IR-induced DNA damage differs between female and male PGCs post-sex determination. IR of female PGCs caused uncoupling of germ cell differentiation and meiotic initiation, while male PGCs exhibited repression of piRNA metabolism and transposon derepression. We also used whole-genome single-cell DNA sequencing to reveal that genetic rescue of DNA repair-deficient germ cells (Fancm−/−) leads to increased mutation incidence and biases. Importantly, our work uncovers novel insights into how PGCs exposed to DNA damage can become developmentally defective, leaving only those genetically fit cells to establish the adult germline.
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Affiliation(s)
- Jordana C Bloom
- Department of Biomedical Sciences,, Cornell University, Ithaca, New York 14853, USA.,Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA
| | - John C Schimenti
- Department of Biomedical Sciences,, Cornell University, Ithaca, New York 14853, USA.,Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA
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22
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Halliwell J, Barbaric I, Andrews PW. Acquired genetic changes in human pluripotent stem cells: origins and consequences. Nat Rev Mol Cell Biol 2020; 21:715-728. [DOI: 10.1038/s41580-020-00292-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2020] [Indexed: 12/14/2022]
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23
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Su J, Zhu D, Huo Z, Gingold JA, Ang YS, Tu J, Zhou R, Lin Y, Luo H, Yang H, Zhao R, Schaniel C, Moore KA, Lemischka IR, Lee DF. Genomic Integrity Safeguards Self-Renewal in Embryonic Stem Cells. Cell Rep 2020; 28:1400-1409.e4. [PMID: 31390555 PMCID: PMC6708277 DOI: 10.1016/j.celrep.2019.07.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 04/25/2019] [Accepted: 07/02/2019] [Indexed: 01/06/2023] Open
Abstract
A multitude of signals are coordinated to maintain self-renewal in embryonic stem cells (ESCs). To unravel the essential internal and external signals required for sustaining the ESC state, we expand upon a set of ESC pluripotency-associated phosphoregulators (PRs) identified previously by short hairpin RNA (shRNA) screening. In addition to the previously described Aurka, we identify 4 additional PRs (Bub1b, Chek1, Ppm1g, and Ppp2r1b) whose depletion compromises self-renewal and leads to consequent differentiation. Global gene expression profiling and computational analyses reveal that knockdown of the 5 PRs leads to DNA damage/genome instability, activating p53 and culminating in ESC differentiation. Similarly, depletion of genome integrity-associated genes involved in DNA replication and checkpoint, mRNA processing, and Charcot-Marie-Tooth disease lead to compromise of ESC self-renewal via an increase in p53 activity. Our studies demonstrate an essential link between genomic integrity and developmental cell fate regulation in ESCs.
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Affiliation(s)
- Jie Su
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; The Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Cancer Biology and Genetics Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Dandan Zhu
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Zijun Huo
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA; Department of Endocrinology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, China
| | - Julian A Gingold
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; The Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Women's Health Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
| | - Yen-Sin Ang
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; The Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Jian Tu
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA; Department of Musculoskeletal Oncology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, China
| | - Ruoji Zhou
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA; The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Yu Lin
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA; Institute of Clinical Pharmacology, Guangzhou University of Chinese Medicine, Guangzhou 510006, China
| | - Haidan Luo
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA; Department of Pathophysiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Huiling Yang
- Department of Pathophysiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Ruiying Zhao
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Christoph Schaniel
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; The Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Kateri A Moore
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; The Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Ihor R Lemischka
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; The Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Dung-Fang Lee
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; The Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA; The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA; Center for Stem Cell and Regenerative Medicine, The Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA; Center for Precision Health, School of Biomedical Informatics, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
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Zafra MP, Parsons MJ, Kim J, Alonso-Curbelo D, Goswami S, Schatoff EM, Han T, Katti A, Fernandez MTC, Wilkinson JE, Piskounova E, Dow LE. An In Vivo Kras Allelic Series Reveals Distinct Phenotypes of Common Oncogenic Variants. Cancer Discov 2020; 10:1654-1671. [PMID: 32792368 DOI: 10.1158/2159-8290.cd-20-0442] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 06/30/2020] [Accepted: 07/09/2020] [Indexed: 11/16/2022]
Abstract
KRAS is the most frequently mutated oncogene in cancer, yet there is little understanding of how specific KRAS amino acid changes affect tumor initiation, progression, or therapy response. Using high-fidelity CRISPR-based engineering, we created an allelic series of new LSL-Kras mutant mice, reflecting codon 12 and 13 mutations that are highly prevalent in lung (KRASG12C), pancreas (KRASG12R), and colon (KRASG13D) cancers. Induction of each allele in either the murine colon or pancreas revealed striking quantitative and qualitative differences between KRAS mutants in driving the early stages of transformation. Furthermore, using pancreatic organoid models, we show that KRASG13D mutants are sensitive to EGFR inhibition, whereas KRASG12C-mutant organoids are selectively responsive to covalent G12C inhibitors only when EGFR is suppressed. Together, these new mouse strains provide an ideal platform for investigating KRAS biology in vivo and for developing preclinical precision oncology models of KRAS-mutant pancreas, colon, and lung cancers. SIGNIFICANCE: KRAS is the most frequently mutated oncogene. Here, we describe new preclinical models that mimic tissue-selective KRAS mutations and show that each mutation has distinct cellular consequences in vivo and carries differential sensitivity to targeted therapeutic agents.See related commentary by Kostyrko and Sweet-Cordero, p. 1626.This article is highlighted in the In This Issue feature, p. 1611.
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Affiliation(s)
- Maria Paz Zafra
- Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, New York.
| | - Marie J Parsons
- Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, New York
| | - Jangkyung Kim
- Weill Cornell Graduate School of Medical Sciences, Weill Cornell Medicine, New York, New York
| | - Direna Alonso-Curbelo
- Cancer Biology and Genetics, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Sukanya Goswami
- Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, New York
| | - Emma M Schatoff
- Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, New York.,Weill Cornell/Rockefeller/Sloan Kettering Tri-Institutional MD-PhD Program, New York, New York
| | - Teng Han
- Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, New York.,Weill Cornell Graduate School of Medical Sciences, Weill Cornell Medicine, New York, New York
| | - Alyna Katti
- Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, New York.,Weill Cornell Graduate School of Medical Sciences, Weill Cornell Medicine, New York, New York
| | | | - John E Wilkinson
- Department of Pathology, University of Michigan, Ann Arbor, Michigan.,Department of Comparative Medicine, University of Washington, Seattle, Washington
| | - Elena Piskounova
- Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, New York.,Department of Dermatology, Weill Cornell Medicine, New York, New York.,Department of Biochemistry, Weill Cornell Medicine, New York, New York
| | - Lukas E Dow
- Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, New York. .,Department of Biochemistry, Weill Cornell Medicine, New York, New York.,Department of Medicine, Weill Cornell Medicine, New York, New York
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25
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SOX2 and p53 Expression Control Converges in PI3K/AKT Signaling with Versatile Implications for Stemness and Cancer. Int J Mol Sci 2020; 21:ijms21144902. [PMID: 32664542 PMCID: PMC7402325 DOI: 10.3390/ijms21144902] [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: 05/29/2020] [Revised: 07/03/2020] [Accepted: 07/08/2020] [Indexed: 12/12/2022] Open
Abstract
Stemness and reprogramming involve transcriptional master regulators that suppress cell differentiation while promoting self-renewal. A distinguished example thereof is SOX2, a high mobility group (HMG)-box transcription factor (TF), whose subcellular localization and turnover regulation in embryonic, induced-pluripotent, and cancer stem cells (ESCs, iPSCs, and CSCs, respectively) is mediated by the PI3K/AKT/SOX2 axis, a stem cell-specific branch of the PI3K/AKT signaling pathway. Further effector functions associated with PI3K/AKT induction include cell cycle progression, cellular (mass) growth, and the suppression of apoptosis. Apoptosis, however, is a central element of DNA damage response (DDR), where it provides a default mechanism for cell clearance when DNA integrity cannot be maintained. A key player in DDR is tumor suppressor p53, which accumulates upon DNA-damage and is counter-balanced by PI3K/AKT enforced turnover. Accordingly, stemness sustaining SOX2 expression and p53-dependent DDR mechanisms show molecular–functional overlap in PI3K/AKT signaling. This constellation proves challenging for stem cells whose genomic integrity is a functional imperative for normative ontogenesis. Unresolved mutations in stem and early progenitor cells may in fact provoke transformation and cancer development. Such mechanisms are also particularly relevant for iPSCs, where genetic changes imposed through somatic cell reprogramming may promote DNA damage. The current review aims to summarize the latest advances in the understanding of PI3K/AKT/SOX2-driven stemness and its intertwined relations to p53-signaling in DDR under conditions of pluripotency, reprogramming, and transformation.
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26
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Xia B, Yan Y, Baron M, Wagner F, Barkley D, Chiodin M, Kim SY, Keefe DL, Alukal JP, Boeke JD, Yanai I. Widespread Transcriptional Scanning in the Testis Modulates Gene Evolution Rates. Cell 2020; 180:248-262.e21. [PMID: 31978344 DOI: 10.1016/j.cell.2019.12.015] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 09/04/2019] [Accepted: 12/12/2019] [Indexed: 02/07/2023]
Abstract
The testis expresses the largest number of genes of any mammalian organ, a finding that has long puzzled molecular biologists. Our single-cell transcriptomic data of human and mouse spermatogenesis provide evidence that this widespread transcription maintains DNA sequence integrity in the male germline by correcting DNA damage through a mechanism we term transcriptional scanning. We find that genes expressed during spermatogenesis display lower mutation rates on the transcribed strand and have low diversity in the population. Moreover, this effect is fine-tuned by the level of gene expression during spermatogenesis. The unexpressed genes, which in our model do not benefit from transcriptional scanning, diverge faster over evolutionary timescales and are enriched for sensory and immune-defense functions. Collectively, we propose that transcriptional scanning shapes germline mutation signatures and modulates mutation rates in a gene-specific manner, maintaining DNA sequence integrity for the bulk of genes but allowing for faster evolution in a specific subset.
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Affiliation(s)
- Bo Xia
- Institute for Computational Medicine, NYU Langone Health, New York, NY 10016, USA; Institute for Systems Genetics, NYU Langone Health, New York, NY 10016, USA
| | - Yun Yan
- Institute for Computational Medicine, NYU Langone Health, New York, NY 10016, USA
| | - Maayan Baron
- Institute for Computational Medicine, NYU Langone Health, New York, NY 10016, USA
| | - Florian Wagner
- Institute for Computational Medicine, NYU Langone Health, New York, NY 10016, USA
| | - Dalia Barkley
- Institute for Computational Medicine, NYU Langone Health, New York, NY 10016, USA
| | - Marta Chiodin
- Institute for Computational Medicine, NYU Langone Health, New York, NY 10016, USA
| | - Sang Y Kim
- Department of Pathology, NYU Langone Health, New York, NY 10016, USA
| | - David L Keefe
- Department of Obstetrics and Gynecology, NYU Langone Health, New York, NY 10016, USA
| | - Joseph P Alukal
- Department of Obstetrics and Gynecology, NYU Langone Health, New York, NY 10016, USA
| | - Jef D Boeke
- Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA; Institute for Systems Genetics, NYU Langone Health, New York, NY 10016, USA
| | - Itai Yanai
- Institute for Computational Medicine, NYU Langone Health, New York, NY 10016, USA; Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA.
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27
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Padgett J, Santos SDM. From clocks to dominoes: lessons on cell cycle remodelling from embryonic stem cells. FEBS Lett 2020; 594:2031-2045. [PMID: 32535913 DOI: 10.1002/1873-3468.13862] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 05/01/2020] [Accepted: 05/27/2020] [Indexed: 12/21/2022]
Abstract
Cell division is a fundamental cellular process and the evolutionarily conserved networks that control cell division cycles adapt during development, tissue regeneration, cell de-differentiation and reprogramming, and a variety of pathological conditions. Embryonic development is a prime example of such versatility: fast, clock-like divisions hallmarking embryonic cells at early developmental stages become slower and controlled during cellular differentiation and lineage specification. In this review, we compare and contrast the unique cell cycle of mouse and human embryonic stem cells with that of early embryonic cells and of differentiated cells. We propose that embryonic stem cells provide an extraordinarily useful model system to understand cell cycle remodelling during embryonic-to-somatic transitions. We discuss how cell cycle networks help sustain embryonic stem cell pluripotency and self-renewal and how they safeguard cell identity and proper cell number in differentiated cells. Finally, we highlight the incredible diversity in cell cycle regulation within mammals and discuss the implications of studying cell cycle remodelling for understanding healthy and disease states.
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Affiliation(s)
- Joe Padgett
- Quantitative Cell Biology Lab, The Francis Crick Institute, London, UK
| | - Silvia D M Santos
- Quantitative Cell Biology Lab, The Francis Crick Institute, London, UK
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28
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Jaiswal SK, Oh JJ, DePamphilis ML. Cell cycle arrest and apoptosis are not dependent on p53 prior to p53-dependent embryonic stem cell differentiation. Stem Cells 2020; 38:1091-1106. [PMID: 32478947 DOI: 10.1002/stem.3199] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 04/11/2020] [Accepted: 04/16/2020] [Indexed: 12/29/2022]
Abstract
Previous efforts to determine whether or not the transcription factor and tumor suppressor protein p53 is required for DNA damage-induced apoptosis in pluripotent embryonic stem cells (ESCs) produced contradictory conclusions. To resolve this issue, p53+/+ and p53-/- ESCs derived by two different methods were used to quantify time-dependent changes in nuclear DNA content; annexin-V binding; cell permeabilization; and protein expression, modification, and localization. The results revealed that doxorubicin (Adriamycin [ADR]) concentrations 10 to 40 times less than commonly used in previous studies induced the DNA damage-dependent G2-checkpoint and completed apoptosis within the same time frame, regardless of the presence or absence of p53, p21, and PUMA. Increased ADR concentrations delayed initiation of apoptosis in p53-/- ESCs, but the rates of apoptosis remained equivalent. Similar results were obtained by inducing apoptosis with either staurosporine inhibition of kinase activities or WX8 disruption of lysosome homeostasis. Differentiation of ESCs by LIF deprivation revealed p53-dependent formation of haploid cells, increased genomic stability, and suppression of the G2-checkpoint. Minimal induction of DNA damage now resulted in p53-facilitated apoptosis, but regulation of pluripotent gene expression remained p53-independent. Primary embryonic fibroblasts underwent p53-dependent total cell cycle arrest (a prelude to cell senescence), and p53-independent apoptosis occurred in the presence of 10-fold higher levels of ADR, consistent with previous studies. Taken together, these results reveal that the multiple roles of p53 in cell cycle regulation and apoptosis are first acquired during pluripotent stem cell differentiation.
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Affiliation(s)
- Sushil K Jaiswal
- National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - John J Oh
- National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Melvin L DePamphilis
- National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
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29
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Thompson O, von Meyenn F, Hewitt Z, Alexander J, Wood A, Weightman R, Gregory S, Krueger F, Andrews S, Barbaric I, Gokhale PJ, Moore HD, Reik W, Milo M, Nik-Zainal S, Yusa K, Andrews PW. Low rates of mutation in clinical grade human pluripotent stem cells under different culture conditions. Nat Commun 2020; 11:1528. [PMID: 32251294 PMCID: PMC7089967 DOI: 10.1038/s41467-020-15271-3] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 02/24/2020] [Indexed: 12/15/2022] Open
Abstract
The occurrence of repetitive genomic changes that provide a selective growth advantage in pluripotent stem cells is of concern for their clinical application. However, the effect of different culture conditions on the underlying mutation rate is unknown. Here we show that the mutation rate in two human embryonic stem cell lines derived and banked for clinical application is low and not substantially affected by culture with Rho Kinase inhibitor, commonly used in their routine maintenance. However, the mutation rate is reduced by >50% in cells cultured under 5% oxygen, when we also found alterations in imprint methylation and reversible DNA hypomethylation. Mutations are evenly distributed across the chromosomes, except for a slight increase on the X-chromosome, and an elevation in intergenic regions suggesting that chromatin structure may affect mutation rate. Overall the results suggest that pluripotent stem cells are not subject to unusually high rates of genetic or epigenetic alterations.
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Affiliation(s)
- Oliver Thompson
- The Centre for Stem Cell Biology, Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Ferdinand von Meyenn
- Epigenetics Programme, Babraham Institute, Cambridge, CB22 3AT, UK
- Department of Medical & Molecular Genetics, King's College London, London, SE1 9RT, UK
- Institute of Food, Nutrition and Health, ETH Zurich, 8603, Schwerzenbach, Switzerland
| | - Zoe Hewitt
- The Centre for Stem Cell Biology, Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - John Alexander
- The Centre for Stem Cell Biology, Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
- Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
| | - Andrew Wood
- The Centre for Stem Cell Biology, Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Richard Weightman
- The Centre for Stem Cell Biology, Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Sian Gregory
- The Centre for Stem Cell Biology, Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Felix Krueger
- Bioinformatics Group, Babraham Institute, Cambridge, CB22 3AT, UK
| | - Simon Andrews
- Bioinformatics Group, Babraham Institute, Cambridge, CB22 3AT, UK
| | - Ivana Barbaric
- The Centre for Stem Cell Biology, Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Paul J Gokhale
- The Centre for Stem Cell Biology, Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Harry D Moore
- The Centre for Stem Cell Biology, Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Wolf Reik
- Epigenetics Programme, Babraham Institute, Cambridge, CB22 3AT, UK
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Marta Milo
- The Centre for Stem Cell Biology, Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Serena Nik-Zainal
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
- Academic Laboratory of Medical Genetics, Cambridge University Hospitals NHS Foundation Trust, Box 238, Lv6 Addenbrooke' Treatment Centre, Cambridge Biomedical Research Campus, Cambridge, CB2 0QQ, UK
- MRC Cancer Unit, University of Cambridge, Hutchinson/MRC Research Centre, Box 1297, Cambridge Biomedical Campus, Cambridge, CB2 0XZ, UK
| | - Kosuke Yusa
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK.
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, 606-8507, Japan.
| | - Peter W Andrews
- The Centre for Stem Cell Biology, Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK.
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30
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Cops5 safeguards genomic stability of embryonic stem cells through regulating cellular metabolism and DNA repair. Proc Natl Acad Sci U S A 2020; 117:2519-2525. [PMID: 31964807 DOI: 10.1073/pnas.1915079117] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The highly conserved COP9 signalosome (CSN), composed of 8 subunits (Cops1 to Cops8), has been implicated in pluripotency maintenance of human embryonic stem cells (ESCs). Yet, the mechanism for the CSN to regulate pluripotency remains elusive. We previously showed that Cops2, independent of the CSN, is essential for the pluripotency maintenance of mouse ESCs. In this study, we set out to investigate how Cops5 and Cops8 regulate ESC differentiation and tried to establish Cops5 and Cops8 knockout (KO) ESC lines by CRISPR/Cas9. To our surprise, no Cops5 KO ESC clones were identified out of 127 clones, while three Cops8 KO ESC lines were established out of 70 clones. We then constructed an inducible Cops5 KO ESC line. Cops5 KO leads to decreased expression of the pluripotency marker Nanog, proliferation defect, G2/M cell-cycle arrest, and apoptosis of ESCs. Further analysis revealed dual roles of Cops5 in maintaining genomic stability of ESCs. On one hand, Cops5 suppresses the autophagic degradation of Mtch2 to direct cellular metabolism toward glycolysis and minimize reactive oxygen species (ROS) production, thereby reducing endogenous DNA damage. On the other hand, Cops5 is required for high DNA damage repair (DDR) activities in ESCs. Without Cops5, elevated ROS and reduced DDR activities lead to DNA damage accumulation in ESCs. Subsequently, p53 is activated to trigger G2/M arrest and apoptosis. Altogether, our studies reveal an essential role of Cops5 in maintaining genome integrity and self-renewal of ESCs by regulating cellular metabolism and DDR pathways.
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31
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Affiliation(s)
- Roberto Bolli
- From the Institute of Molecular Cardiology, University of Louisville, KY
| | - Marcin Wysoczynski
- From the Institute of Molecular Cardiology, University of Louisville, KY
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32
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Brazhnik K, Sun S, Alani O, Kinkhabwala M, Wolkoff AW, Maslov AY, Dong X, Vijg J. Single-cell analysis reveals different age-related somatic mutation profiles between stem and differentiated cells in human liver. SCIENCE ADVANCES 2020; 6:eaax2659. [PMID: 32064334 PMCID: PMC6994209 DOI: 10.1126/sciadv.aax2659] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 11/22/2019] [Indexed: 06/10/2023]
Abstract
Accumulating somatic mutations have been implicated in age-related cellular degeneration and death. Because of their random nature and low abundance, somatic mutations are difficult to detect except in single cells or clonal cell lineages. Here, we show that in single hepatocytes from human liver, an organ exposed to high levels of genotoxic stress, somatic mutation frequencies are high and increase substantially with age. Considerably lower mutation frequencies were observed in liver stem cells (LSCs) and organoids derived from them. Mutational spectra in hepatocytes showed signatures of oxidative stress that were different in old age and in LSCs. A considerable number of mutations were found in functional parts of the liver genome, suggesting that somatic mutagenesis could causally contribute to the age-related functional decline and increased incidence of disease of human liver. These results underscore the importance of stem cells in maintaining genome sequence integrity in aging somatic tissues.
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Affiliation(s)
- K. Brazhnik
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, USA
| | - S. Sun
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, USA
| | - O. Alani
- Division of Transplant Surgery, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - M. Kinkhabwala
- Division of Transplant Surgery, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - A. W. Wolkoff
- Marion Bessin Liver Research Center, Division of Hepatology, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY, USA
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - A. Y. Maslov
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, USA
| | - X. Dong
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, USA
| | - J. Vijg
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, USA
- Center for Single-Cell Omics in Aging and Disease, School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
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Abstract
Pluripotent stem cells (PSCs) are capable of unlimited self-renewal in culture and differentiation into all functional cell types in the body, and thus hold great promise for regenerative medicine. To achieve their clinical potential, it is critical for PSCs to maintain genomic stability during the extended proliferation. The critical tumor suppressor p53 is required to maintain genomic stability of mammalian cells. In response to DNA damage or oncogenic stress, p53 plays multiple roles in maintaining genomic stability of somatic cells by inducing cell cycle arrest, apoptosis, and senescence to prevent the passage of genetic mutations to the daughter cells. p53 is also required to maintain the genomic stability of PSCs. However, in response to the genotoxic stresses, a primary role of p53 in PSCs is to induce the differentiation of PSCs and inhibit pluripotency, providing mechanisms to maintain the genomic stability of the self-renewing PSCs. In addition, the roles of p53 in cellular metabolism might also contribute to genomic stability of PSCs by limiting oxidative stress. In summary, the elucidation of the roles of p53 in PSCs will be a prerequisite for developing safe PSC-based cell therapy.
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Schnepp PM, Chen M, Keller ET, Zhou X. SNV identification from single-cell RNA sequencing data. Hum Mol Genet 2019; 28:3569-3583. [PMID: 31504520 PMCID: PMC7279618 DOI: 10.1093/hmg/ddz207] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 08/09/2019] [Accepted: 08/16/2019] [Indexed: 01/22/2023] Open
Abstract
Integrating single-cell RNA sequencing (scRNA-seq) data with genotypes obtained from DNA sequencing studies facilitates the detection of functional genetic variants underlying cell type-specific gene expression variation. Unfortunately, most existing scRNA-seq studies do not come with DNA sequencing data; thus, being able to call single nucleotide variants (SNVs) from scRNA-seq data alone can provide crucial and complementary information, detection of functional SNVs, maximizing the potential of existing scRNA-seq studies. Here, we perform extensive analyses to evaluate the utility of two SNV calling pipelines (GATK and Monovar), originally designed for SNV calling in either bulk or single-cell DNA sequencing data. In both pipelines, we examined various parameter settings to determine the accuracy of the final SNV call set and provide practical recommendations for applied analysts. We found that combining all reads from the single cells and following GATK Best Practices resulted in the highest number of SNVs identified with a high concordance. In individual single cells, Monovar resulted in better quality SNVs even though none of the pipelines analyzed is capable of calling a reasonable number of SNVs with high accuracy. In addition, we found that SNV calling quality varies across different functional genomic regions. Our results open doors for novel ways to leverage the use of scRNA-seq for the future investigation of SNV function.
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Affiliation(s)
- Patricia M Schnepp
- Department of Urology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Mengjie Chen
- Department of Medicine, University of Chicago, Chicago, Illinois, USA
| | - Evan T Keller
- Department of Urology, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Biointerfaces Institute, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Xiang Zhou
- Department of Biostatistics, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Center for Statistical Genetics, University of Michigan Medical School, Ann Arbor, Michigan, USA
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35
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Reviving rare chicken breeds using genetically engineered sterility in surrogate host birds. Proc Natl Acad Sci U S A 2019; 116:20930-20937. [PMID: 31575742 DOI: 10.1073/pnas.1906316116] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In macrolecithal species, cryopreservation of the oocyte and zygote is not possible due to the large size and quantity of lipid deposited within the egg. For birds, this signifies that cryopreserving and regenerating a species from frozen cellular material are currently technically unfeasible. Diploid primordial germ cells (PGCs) are a potential means to freeze down the entire genome and reconstitute an avian species from frozen material. Here, we examine the use of genetically engineered (GE) sterile female layer chicken as surrogate hosts for the transplantation of cryopreserved avian PGCs from rare heritage breeds of chicken. We first amplified PGC numbers in culture before cryopreservation and subsequent transplantation into host GE embryos. We found that all hatched offspring from the chimera GE hens were derived from the donor rare heritage breed broiler PGCs, and using cryopreserved semen, we were able to produce pure offspring. Measurement of the mutation rate of PGCs in culture revealed that 2.7 × 10-10 de novo single-nucleotide variants (SNVs) were generated per cell division, which is comparable with other stem cell lineages. We also found that endogenous avian leukosis virus (ALV) retroviral insertions were not mobilized during in vitro propagation. Taken together, these results show that mutation rates are no higher than normal stem cells, essential if we are to conserve avian breeds. Thus, GE sterile avian surrogate hosts provide a viable platform to conserve and regenerate avian species using cryopreserved PGCs.
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Bloom JC, Loehr AR, Schimenti JC, Weiss RS. Germline genome protection: implications for gamete quality and germ cell tumorigenesis. Andrology 2019; 7:516-526. [PMID: 31119900 DOI: 10.1111/andr.12651] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 04/25/2019] [Accepted: 04/26/2019] [Indexed: 12/19/2022]
Abstract
BACKGROUND Germ cells have a unique and critical role as the conduit for hereditary information and therefore employ multiple strategies to protect genomic integrity and avoid mutations. Unlike somatic cells, which often respond to DNA damage by arresting the cell cycle and conducting DNA repair, germ cells as well as long-lived pluripotent stem cells typically avoid the use of error-prone repair mechanisms and favor apoptosis, reducing the risk of genetic alterations. Testicular germ cell tumors, the most common cancers of young men, arise from pre-natal germ cells. OBJECTIVES To summarize the current understanding of DNA damage response mechanisms in pre-meiotic germ cells and to discuss how they impact both the origins of testicular germ cell tumors and their remarkable responsiveness to genotoxic chemotherapy. MATERIALS AND METHODS We conducted a review of literature gathered from PubMed regarding the DNA damage response properties of testicular germ cell tumors and the germ cells from which they arise, as well as the influence of these mechanisms on therapeutic responses by testicular germ cell tumors. RESULTS AND DISCUSSION This review provides a comprehensive evaluation of how the developmental origins of male germ cells and their inherent germ cell-like DNA damage response directly impact the development and therapeutic sensitivity of testicular germ cell tumors. CONCLUSIONS The DNA damage response of germ cells directly impacts the development and therapeutic sensitivity of testicular germ cell tumors. Recent advances in the study of primordial germ cells, post-natal mitotically dividing germ cells, and pluripotent stem cells will allow for new investigations into the initiation, progression, and treatment of testicular germ cell tumors.
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Affiliation(s)
- J C Bloom
- Department of Biomedical Sciences, Cornell University, Ithaca, NY, USA
| | - A R Loehr
- Department of Biomedical Sciences, Cornell University, Ithaca, NY, USA
| | - J C Schimenti
- Department of Biomedical Sciences, Cornell University, Ithaca, NY, USA
| | - R S Weiss
- Department of Biomedical Sciences, Cornell University, Ithaca, NY, USA
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Mohammad K, Dakik P, Medkour Y, Mitrofanova D, Titorenko VI. Quiescence Entry, Maintenance, and Exit in Adult Stem Cells. Int J Mol Sci 2019; 20:ijms20092158. [PMID: 31052375 PMCID: PMC6539837 DOI: 10.3390/ijms20092158] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 04/24/2019] [Accepted: 04/28/2019] [Indexed: 12/13/2022] Open
Abstract
Cells of unicellular and multicellular eukaryotes can respond to certain environmental cues by arresting the cell cycle and entering a reversible state of quiescence. Quiescent cells do not divide, but can re-enter the cell cycle and resume proliferation if exposed to some signals from the environment. Quiescent cells in mammals and humans include adult stem cells. These cells exhibit improved stress resistance and enhanced survival ability. In response to certain extrinsic signals, adult stem cells can self-renew by dividing asymmetrically. Such asymmetric divisions not only allow the maintenance of a population of quiescent cells, but also yield daughter progenitor cells. A multistep process of the controlled proliferation of these progenitor cells leads to the formation of one or more types of fully differentiated cells. An age-related decline in the ability of adult stem cells to balance quiescence maintenance and regulated proliferation has been implicated in many aging-associated diseases. In this review, we describe many traits shared by different types of quiescent adult stem cells. We discuss how these traits contribute to the quiescence, self-renewal, and proliferation of adult stem cells. We examine the cell-intrinsic mechanisms that allow establishing and sustaining the characteristic traits of adult stem cells, thereby regulating quiescence entry, maintenance, and exit.
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Affiliation(s)
- Karamat Mohammad
- Department of Biology, Concordia University, 7141 Sherbrooke Street, West, SP Building, Room 501-13, Montreal, QC H4B 1R6, Canada.
| | - Paméla Dakik
- Department of Biology, Concordia University, 7141 Sherbrooke Street, West, SP Building, Room 501-13, Montreal, QC H4B 1R6, Canada.
| | - Younes Medkour
- Department of Biology, Concordia University, 7141 Sherbrooke Street, West, SP Building, Room 501-13, Montreal, QC H4B 1R6, Canada.
| | - Darya Mitrofanova
- Department of Biology, Concordia University, 7141 Sherbrooke Street, West, SP Building, Room 501-13, Montreal, QC H4B 1R6, Canada.
| | - Vladimir I Titorenko
- Department of Biology, Concordia University, 7141 Sherbrooke Street, West, SP Building, Room 501-13, Montreal, QC H4B 1R6, Canada.
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38
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Kohutova A, Raška J, Kruta M, Seneklova M, Barta T, Fojtik P, Jurakova T, Walter CA, Hampl A, Dvorak P, Rotrekl V. Ligase 3–mediated end‐joining maintains genome stability of human embryonic stem cells. FASEB J 2019; 33:6778-6788. [DOI: 10.1096/fj.201801877rr] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Aneta Kohutova
- Department of BiologyMasaryk UniversityBrnoCzech Republic
- International Clinical Research Center (ICRC)St. Anne's University HospitalBrnoCzech Republic
| | - Jan Raška
- Department of BiologyMasaryk UniversityBrnoCzech Republic
| | - Miriama Kruta
- Department of BiologyMasaryk UniversityBrnoCzech Republic
| | | | - Tomas Barta
- Department of BiologyMasaryk UniversityBrnoCzech Republic
| | - Petr Fojtik
- Department of BiologyMasaryk UniversityBrnoCzech Republic
| | | | - Christi A. Walter
- Department of Cell Systems and AnatomyThe University of Texas Health Science Center at San AntonioSan AntonioTexasUSA
| | - Ales Hampl
- Department of Histology and EmbryologyFaculty of MedicineMasaryk UniversityBrnoCzech Republic
- International Clinical Research Center (ICRC)St. Anne's University HospitalBrnoCzech Republic
| | - Petr Dvorak
- Department of BiologyMasaryk UniversityBrnoCzech Republic
- International Clinical Research Center (ICRC)St. Anne's University HospitalBrnoCzech Republic
| | - Vladimir Rotrekl
- Department of BiologyMasaryk UniversityBrnoCzech Republic
- International Clinical Research Center (ICRC)St. Anne's University HospitalBrnoCzech Republic
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Liang Q, Monetti C, Shutova MV, Neely EJ, Hacibekiroglu S, Yang H, Kim C, Zhang P, Li C, Nagy K, Mileikovsky M, Gyongy I, Sung HK, Nagy A. Linking a cell-division gene and a suicide gene to define and improve cell therapy safety. Nature 2018; 563:701-704. [PMID: 30429614 DOI: 10.1038/s41586-018-0733-7] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 09/27/2018] [Indexed: 12/20/2022]
Abstract
Human pluripotent cell lines hold enormous promise for the development of cell-based therapies. Safety, however, is a crucial prerequisite condition for clinical applications. Numerous groups have attempted to eliminate potentially harmful cells through the use of suicide genes1, but none has quantitatively defined the safety level of transplant therapies. Here, using genome-engineering strategies, we demonstrate the protection of a suicide system from inactivation in dividing cells. We created a transcriptional link between the suicide gene herpes simplex virus thymidine kinase (HSV-TK) and a cell-division gene (CDK1); this combination is designated the safe-cell system. Furthermore, we used a mathematical model to quantify the safety level of the cell therapy as a function of the number of cells that is needed for the therapy and the type of genome editing that is performed. Even with the highly conservative estimates described here, we anticipate that our solution will rapidly accelerate the entry of cell-based medicine into the clinic.
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Affiliation(s)
- Qin Liang
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Claudio Monetti
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada
| | - Maria V Shutova
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada
| | - Eric J Neely
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Sabiha Hacibekiroglu
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Huijuan Yang
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Christopher Kim
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Puzheng Zhang
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada
| | - Chengjin Li
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada
| | - Kristina Nagy
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Maria Mileikovsky
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada
| | - Istvan Gyongy
- School of Mathematics and Maxwell Institute, The University of Edinburgh, Edinburgh, UK
| | - Hoon-Ki Sung
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada.,The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
| | - Andras Nagy
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada. .,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada. .,Australian Regenerative Medicine Institute, Monash University, Melbourne, Victoria, Australia. .,Department of Obstetrics & Gynaecology, University of Toronto, Toronto, Ontario, Canada.
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40
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Lisowski P, Kannan P, Mlody B, Prigione A. Mitochondria and the dynamic control of stem cell homeostasis. EMBO Rep 2018; 19:embr.201745432. [PMID: 29661859 DOI: 10.15252/embr.201745432] [Citation(s) in RCA: 118] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 12/22/2017] [Accepted: 03/21/2018] [Indexed: 12/12/2022] Open
Abstract
The maintenance of cellular identity requires continuous adaptation to environmental changes. This process is particularly critical for stem cells, which need to preserve their differentiation potential over time. Among the mechanisms responsible for regulating cellular homeostatic responses, mitochondria are emerging as key players. Given their dynamic and multifaceted role in energy metabolism, redox, and calcium balance, as well as cell death, mitochondria appear at the interface between environmental cues and the control of epigenetic identity. In this review, we describe how mitochondria have been implicated in the processes of acquisition and loss of stemness, with a specific focus on pluripotency. Dissecting the biological functions of mitochondria in stem cell homeostasis and differentiation will provide essential knowledge to understand the dynamics of cell fate modulation, and to establish improved stem cell-based medical applications.
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Affiliation(s)
- Pawel Lisowski
- Max Delbrueck Center for Molecular Medicine (MDC), Berlin, Germany.,Institute of Genetics and Animal Breeding, Polish Academy of Sciences, Magdalenka, Poland.,Centre for Preclinical Research and Technology (CePT), Warsaw Medical University, Warsaw, Poland
| | - Preethi Kannan
- Max Delbrueck Center for Molecular Medicine (MDC), Berlin, Germany
| | - Barbara Mlody
- Max Delbrueck Center for Molecular Medicine (MDC), Berlin, Germany
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41
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Hébert JM, Vijg J. Cell Replacement to Reverse Brain Aging: Challenges, Pitfalls, and Opportunities. Trends Neurosci 2018; 41:267-279. [PMID: 29548515 DOI: 10.1016/j.tins.2018.02.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 01/23/2018] [Accepted: 02/12/2018] [Indexed: 12/21/2022]
Abstract
Current antiaging strategies focusing on druggable targets have met with relatively limited success to date. Replacement of cells, tissues, and organs could provide an alternative means for targeting age-induced damage and potentially eliminating some of it. However, before this is a viable option, numerous challenges need to be addressed. Most notably, whether the brain, which defines our self-identity, is amenable to replacement therapies is unclear. Here, we consider whether progressive cell replacement is a potential approach to reverse brain aging without grossly altering function. We focus mainly on the neocortex, seat of our highest cognitive functions, because of abundant knowledge on neocortical development, plasticity, and how the neocortex can functionally incorporate new neurons. We outline the primary challenges for brain cell replacement, and key areas that require further investigation.
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Affiliation(s)
- Jean M Hébert
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA; Department of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | - Jan Vijg
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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42
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McFarlane RJ, Wakeman JA. Meiosis-like Functions in Oncogenesis: A New View of Cancer. Cancer Res 2017; 77:5712-5716. [PMID: 29061671 DOI: 10.1158/0008-5472.can-17-1535] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 08/03/2017] [Accepted: 08/16/2017] [Indexed: 11/16/2022]
Abstract
Cancer cells have many abnormal characteristics enabling tumors to grow, spread, and avoid immunologic and therapeutic destruction. Central to this is the innate ability of populations of cancer cells to rapidly evolve. One feature of many cancers is that they activate genes that are normally associated with distinct developmental states, including germ cell-specific genes. This has historically led to the proposal that tumors take on embryonal characteristics, the so called embryonal theory of cancer. However, one group of germline genes, not directly associated with embryonic somatic tissue genesis, is the one that encodes the specific factors to drive the unique reductional chromosome segregation of meiosis I, which also results in chromosomal exchanges. Here, we propose that meiosis I-specific modulators of reductional segregation can contribute to oncogenic chromosome dynamics and that the embryonal theory for cancer cell growth/proliferation is overly simplistic, as meiotic factors are not a feature of most embryonic tissue development. We postulate that some meiotic chromosome-regulatory functions contribute to a soma-to-germline model for cancer, in which activation of germline (including meiosis) functions drive oncogenesis, and we extend this to propose that meiotic factors could be powerful sources of targets for therapeutics and biomonitoring in oncology. Cancer Res; 77(21); 5712-6. ©2017 AACR.
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Affiliation(s)
- Ramsay J McFarlane
- North West Cancer Research Institute, School of Medical Sciences, Bangor University, Bangor, Gwynedd, United Kingdom.
| | - Jane A Wakeman
- North West Cancer Research Institute, School of Medical Sciences, Bangor University, Bangor, Gwynedd, United Kingdom
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43
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Du H, Pan B, Chen T. Evaluation of chemical mutagenicity using next generation sequencing: A review. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART C, ENVIRONMENTAL CARCINOGENESIS & ECOTOXICOLOGY REVIEWS 2017; 35:140-158. [PMID: 28506110 DOI: 10.1080/10590501.2017.1328831] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Mutations are heritable changes in the nucleotide sequence of DNA that can lead to many adverse effects. Genotoxicity assays have been used to identify chemical mutagenicity. Recently, next generation sequencing (NGS) has been used for this purpose. In this review, we present the progress in NGS application for assessing mutagenicity of chemicals, including the methods used for detecting the induced mutations, bioinformatics tools for analyzing the sequencing data, and chemicals whose mutagenicity has been evaluated using NGS. Available information suggests that NGS technology has unparalleled advantages for evaluating mutagenicity of chemicals can be applied for the next generation of mutagenicity tests.
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Affiliation(s)
- Hua Du
- a Division of Genetic and Molecular Toxicology, National Center for Toxicological Research , U.S. Food and Drug Administration , Jefferson , Arkansas , USA
| | - Bohu Pan
- a Division of Genetic and Molecular Toxicology, National Center for Toxicological Research , U.S. Food and Drug Administration , Jefferson , Arkansas , USA
| | - Tao Chen
- a Division of Genetic and Molecular Toxicology, National Center for Toxicological Research , U.S. Food and Drug Administration , Jefferson , Arkansas , USA
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44
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Vijg J, Dong X, Zhang L. A high-fidelity method for genomic sequencing of single somatic cells reveals a very high mutational burden. Exp Biol Med (Maywood) 2017; 242:1318-1324. [PMID: 28737476 PMCID: PMC5529006 DOI: 10.1177/1535370217717696] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Postzygotic mutations in somatic cells lead to genome mosaicism and can be the cause of cancer, possibly other human diseases and aging. Somatic mutations are difficult to detect in bulk tissue samples. Here, we review the available assays for measuring somatic mutations, with a focus on recent single-cell, whole genome sequencing methods. Impact statement Somatic mutations cause cancer, possibly other diseases and aging. Yet, very little is known about the frequency of such mutations in vivo, their distribution across the genome, and their possible functional consequences other than cancer. Even in cancer, we do not know the heterogeneity of mutations within a tumor and if seemingly normal cells in its surroundings already have elevated mutation frequencies. Here, we review a new, whole genome amplification system that allows accurate quantification and characterization of single-cell mutational landscapes in human cells and tissues in relation to disease.
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Affiliation(s)
- Jan Vijg
- Department of Genetics, Albert Einstein College of Medicine, Michael F. Price Center, Bronx, NY 10461, USA
| | - Xiao Dong
- Department of Genetics, Albert Einstein College of Medicine, Michael F. Price Center, Bronx, NY 10461, USA
| | - Lei Zhang
- Department of Genetics, Albert Einstein College of Medicine, Michael F. Price Center, Bronx, NY 10461, USA
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45
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Chamorro CI, Zeiai S, Reinfeldt Engberg G, Brodin D, Lundin J, Nordenskjöld A, Fossum M. Study on genetic stability in human urothelial cells
in vitro. J Tissue Eng Regen Med 2017; 12:e720-e726. [DOI: 10.1002/term.2354] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 09/05/2016] [Accepted: 11/09/2016] [Indexed: 02/06/2023]
Affiliation(s)
- Clara Ibel Chamorro
- Department of Women's and Children's Health and Center for Molecular MedicineKarolinska Institutet Stockholm Sweden
| | - Said Zeiai
- Department of Women's and Children's Health and Center for Molecular MedicineKarolinska Institutet Stockholm Sweden
- Department of Pediatric Surgery, Section of Urology, Astrid Lindgren Children's HospitalKarolinska University Hospital Stockholm Sweden
| | - Gisela Reinfeldt Engberg
- Department of Women's and Children's Health and Center for Molecular MedicineKarolinska Institutet Stockholm Sweden
- Department of Pediatric Surgery, Section of Urology, Astrid Lindgren Children's HospitalKarolinska University Hospital Stockholm Sweden
| | - David Brodin
- Department of Biosciences and NutritionKarolinska Institutet Stockholm Sweden
| | - Johanna Lundin
- Department of Women's and Children's Health and Center for Molecular MedicineKarolinska Institutet Stockholm Sweden
| | - Agneta Nordenskjöld
- Department of Women's and Children's Health and Center for Molecular MedicineKarolinska Institutet Stockholm Sweden
- Department of Pediatric Surgery, Section of Urology, Astrid Lindgren Children's HospitalKarolinska University Hospital Stockholm Sweden
| | - Magdalena Fossum
- Department of Women's and Children's Health and Center for Molecular MedicineKarolinska Institutet Stockholm Sweden
- Department of Pediatric Surgery, Section of Urology, Astrid Lindgren Children's HospitalKarolinska University Hospital Stockholm Sweden
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Stambrook PJ, Maher J, Farzaneh F. Cancer Immunotherapy: Whence and Whither. Mol Cancer Res 2017; 15:635-650. [PMID: 28356330 DOI: 10.1158/1541-7786.mcr-16-0427] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 12/22/2016] [Accepted: 01/14/2017] [Indexed: 12/22/2022]
Abstract
The current concepts and practice of cancer immunotherapy evolved from classical experiments that distinguished "self" from "non-self" and the finding that humoral immunity is complemented by cellular immunity. Elucidation of the biology underlying immune checkpoints and interactions between ligands and ligand receptors that govern the immune system's ability to recognize tumor cells as foreign has led to the emergence of new strategies that mobilize the immune system to reverse this apparent tolerance. Some of these approaches have led to new therapies such as the use of mAbs to interfere with the immune checkpoint. Others have exploited molecular technologies to reengineer a subset of T cells to directly engage and kill tumor cells, particularly those of B-cell malignancies. However, before immunotherapy can become a more effective method of cancer care, there are many challenges that remain to be addressed and hurdles to overcome. Included are manipulation of tumor microenvironment (TME) to enhance T effector cell infiltration and access to the tumor, augmentation of tumor MHC expression for adequate presentation of tumor associated antigens, regulation of cytokines and their potential adverse effects, and reduced risk of secondary malignancies as a consequence of mutations generated by the various forms of genetic engineering of immune cells. Despite these challenges, the future of immunotherapy as a standard anticancer therapy is encouraging. Mol Cancer Res; 15(6); 635-50. ©2017 AACR.
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Affiliation(s)
- Peter J Stambrook
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio.
| | - John Maher
- Kings College London, CAR Mechanics Group, Guy's Hospital, London, United Kingdom
| | - Farzin Farzaneh
- Division of Cancer Studies, Department of Haematological Medicine, Kings College London, London, United Kingdom
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47
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Overcoming Pluripotent Stem Cell Dependence on the Repair of Endogenous DNA Damage. Stem Cell Reports 2016; 6:44-54. [PMID: 26771352 PMCID: PMC4719133 DOI: 10.1016/j.stemcr.2015.12.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 11/30/2015] [Accepted: 12/01/2015] [Indexed: 01/27/2023] Open
Abstract
Pluripotent stem cells (PSCs) maintain a low mutation frequency compared with somatic cell types at least in part by preferentially utilizing error-free homologous recombination (HR) for DNA repair. Many endogenous metabolites cause DNA interstrand crosslinks, which are repaired by the Fanconi anemia (FA) pathway using HR. To determine the effect of failed repair of endogenous DNA lesions on PSC biology, we generated iPSCs harboring a conditional FA pathway. Upon FA pathway loss, iPSCs maintained pluripotency but underwent profound G2 arrest and apoptosis, whereas parental fibroblasts grew normally. Mechanistic studies revealed that G2-phase FA-deficient iPSCs possess large γH2AX-RAD51 foci indicative of accrued DNA damage, which correlated with activated DNA-damage signaling through CHK1. CHK1 inhibition specifically rescued the growth of FA-deficient iPSCs for prolonged culture periods, surprisingly without stimulating excessive karyotypic abnormalities. These studies reveal that PSCs possess hyperactive CHK1 signaling that restricts their self-renewal in the absence of error-free DNA repair. Self-renewal but not pluripotency of iPSCs depends on FA pathway function Hyperactive CHK1 limits self-renewal in a conditional FA-deficient iPSC model CHK1 inhibition rescues long-term growth of FA-deficient iPSCs
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48
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Yeang CH, Beckman RA. Long range personalized cancer treatment strategies incorporating evolutionary dynamics. Biol Direct 2016; 11:56. [PMID: 27770811 PMCID: PMC5075220 DOI: 10.1186/s13062-016-0153-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 09/21/2016] [Indexed: 02/07/2023] Open
Abstract
Background Current cancer precision medicine strategies match therapies to static consensus molecular properties of an individual’s cancer, thus determining the next therapeutic maneuver. These strategies typically maintain a constant treatment while the cancer is not worsening. However, cancers feature complicated sub-clonal structure and dynamic evolution. We have recently shown, in a comprehensive simulation of two non-cross resistant therapies across a broad parameter space representing realistic tumors, that substantial improvement in cure rates and median survival can be obtained utilizing dynamic precision medicine strategies. These dynamic strategies explicitly consider intratumoral heterogeneity and evolutionary dynamics, including predicted future drug resistance states, and reevaluate optimal therapy every 45 days. However, the optimization is performed in single 45 day steps (“single-step optimization”). Results Herein we evaluate analogous strategies that think multiple therapeutic maneuvers ahead, considering potential outcomes at 5 steps ahead (“multi-step optimization”) or 40 steps ahead (“adaptive long term optimization (ALTO)”) when recommending the optimal therapy in each 45 day block, in simulations involving both 2 and 3 non-cross resistant therapies. We also evaluate an ALTO approach for situations where simultaneous combination therapy is not feasible (“Adaptive long term optimization: serial monotherapy only (ALTO-SMO)”). Simulations utilize populations of 764,000 and 1,700,000 virtual patients for 2 and 3 drug cases, respectively. Each virtual patient represents a unique clinical presentation including sizes of major and minor tumor subclones, growth rates, evolution rates, and drug sensitivities. While multi-step optimization and ALTO provide no significant average survival benefit, cure rates are significantly increased by ALTO. Furthermore, in the subset of individual virtual patients demonstrating clinically significant difference in outcome between approaches, by far the majority show an advantage of multi-step or ALTO over single-step optimization. ALTO-SMO delivers cure rates superior or equal to those of single- or multi-step optimization, in 2 and 3 drug cases respectively. Conclusion In selected virtual patients incurable by dynamic precision medicine using single-step optimization, analogous strategies that “think ahead” can deliver long-term survival and cure without any disadvantage for non-responders. When therapies require dose reduction in combination (due to toxicity), optimal strategies feature complex patterns involving rapidly interleaved pulses of combinations and high dose monotherapy. Reviewers This article was reviewed by Wendy Cornell, Marek Kimmel, and Andrzej Swierniak. Wendy Cornell and Andrzej Swierniak are external reviewers (not members of the Biology Direct editorial board). Andrzej Swierniak was nominated by Marek Kimmel. Electronic supplementary material The online version of this article (doi:10.1186/s13062-016-0153-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Robert A Beckman
- Departments of Oncology and of Biostatistics, Bioinformatics, and Biomathematics, Lombardi Comprehensive Cancer Center and Innovation Center for Biomedical Informatics, Georgetown University Medical Center, Washington, DC, USA.
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Chen IC, Hernandez C, Xu X, Cooney A, Wang Y, McCarrey JR. Dynamic Variations in Genetic Integrity Accompany Changes in Cell Fate. Stem Cells Dev 2016; 25:1698-1708. [PMID: 27627671 DOI: 10.1089/scd.2016.0221] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Pluripotent stem cells hold the potential to form the basis of novel approaches to treatment of disease in vivo as well as to facilitate the generation of models for human disease, providing powerful avenues to discovery of novel diagnostic biomarkers and/or innovative drug regimens in vitro. However, this will require extensive maintenance, expansion, and manipulation of these cells in culture, which raises a concern regarding the extent to which genetic integrity will be preserved throughout these manipulations. We used a mutation reporter (lacI) transgene approach to conduct direct comparisons of mutation frequencies in cell populations that shared a common origin and genetic identity, but were induced to undergo transitions in cell fate between pluripotent and differentiated states, or vice versa. We confirm that pluripotent cells normally maintain enhanced genetic integrity relative to that in differentiated cells, and we extend this finding to show that dynamic transformations in the relative stringency at which genetic integrity is maintained are associated with transitions between pluripotent and differentiated cellular states. These results provide insight into basic biological distinctions between pluripotent and differentiated cell types that impact genetic integrity in a manner that is directly relevant to the potential clinical use of these cell types.
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Affiliation(s)
- I-Chung Chen
- 1 Department of Biology, University of Texas at San Antonio , San Antonio, Texas
| | - Christine Hernandez
- 1 Department of Biology, University of Texas at San Antonio , San Antonio, Texas
| | - Xueping Xu
- 2 Institute for Applied Cancer Science, The University of Texas MD Anderson Cancer Center , Houston, Texas
| | - Austin Cooney
- 2 Institute for Applied Cancer Science, The University of Texas MD Anderson Cancer Center , Houston, Texas.,3 Department of Pediatrics, Dell Pediatric Research Institute, University of Texas at Austin Dell , Medical School, Austin, Texas
| | - Yufeng Wang
- 1 Department of Biology, University of Texas at San Antonio , San Antonio, Texas
| | - John R McCarrey
- 1 Department of Biology, University of Texas at San Antonio , San Antonio, Texas
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Tsai RYL. Balancing self-renewal against genome preservation in stem cells: How do they manage to have the cake and eat it too? Cell Mol Life Sci 2016; 73:1803-23. [PMID: 26886024 PMCID: PMC5040593 DOI: 10.1007/s00018-016-2152-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 01/18/2016] [Accepted: 01/28/2016] [Indexed: 01/22/2023]
Abstract
Stem cells are endowed with the awesome power of self-renewal and multi-lineage differentiation that allows them to be major contributors to tissue homeostasis. Owing to their longevity and self-renewal capacity, they are also faced with a higher risk of genomic damage compared to differentiated cells. Damage on the genome, if not prevented or repaired properly, will threaten the survival of stem cells and culminate in organ failure, premature aging, or cancer formation. It is therefore of paramount importance that stem cells remain genomically stable throughout life. Given their unique biological and functional requirement, stem cells are thought to manage genotoxic stress somewhat differently from non-stem cells. The focus of this article is to review the current knowledge on how stem cells escape the barrage of oxidative and replicative DNA damage to stay in self-renewal. A clear statement on this subject should help us better understand tissue regeneration, aging, and cancer.
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Affiliation(s)
- Robert Y L Tsai
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M University Health Science Center, 2121 W. Holcombe Blvd, Houston, TX, 77030, USA.
- Department of Molecular and Cellular Medicine, Texas A&M University Health Science Center, College Station, TX, 77843, USA.
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