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Shu J, Jiang J, Wang X, Yang X, Zhao G, Cai T. MDM2 provides TOP2 poison resistance by promoting proteolysis of TOP2βcc in a p53-independent manner. Cell Death Dis 2024; 15:83. [PMID: 38263255 PMCID: PMC10806188 DOI: 10.1038/s41419-024-06474-3] [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: 09/15/2023] [Revised: 01/14/2024] [Accepted: 01/15/2024] [Indexed: 01/25/2024]
Abstract
DNA topoisomerase II (TOP2) is an enzyme that performs a critical function in manipulating DNA topology during replication, transcription, and chromosomal compaction by forming a vital intermediate known as the TOP2-DNA cleavage complex (TOP2cc). Although the TOP2cc is often transient, stabilization can be achieved by TOP2 poisons, a family of anti-cancer chemotherapeutic agents targeting TOP2, such as etoposide (VP-16), and then induce double-strand breaks (DSBs) in cellular DNA. TOP2cc first needs to be proteolyzed before it can be processed by TDP2 for the removal of these protein adducts and to produce clean DNA ends necessary for proper repair. However, the mechanism by which TOP2βcc is proteolyzed has not been thoroughly studied. In this study, we report that after exposure to VP-16, MDM2, a RING-type E3 ubiquitin ligase, attaches to TOP2β and initiates polyubiquitination and proteasomal degradation. Mechanistically, during exposure to VP-16, TOP2β binds to DNA to form TOP2βcc, which promotes MDM2 binding and subsequent TOP2β ubiquitination and degradation, and results in a decrease in TOP2βcc levels. Biologically, MDM2 inactivation abrogates TOP2β degradation, stabilizes TOP2βcc, and subsequently increases the number of TOP2β-concealed DSBs, resulting in the rapid death of cancer cells via the apoptotic process. Furthermore, we demonstrate the combination activity of VP-16 and RG7112, an MDM2 inhibitor, in the xenograft tumor model and in situ lung cancer mouse model. Taken together, the results of our research reveal an underlying mechanism by which MDM2 promotes cancer cell survival in the presence of TOP2 poisons by activating proteolysis of TOP2βcc in a p53-independent manner, and provides a rationale for the combination of MDM2 inhibitors with TOP2 poisons for cancer therapy.
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Affiliation(s)
- Jianfeng Shu
- Department of Thoracic Surgery, Ningbo No.2 Hospital, Ningbo, 315010, Zhejiang, China
- Ningbo Institute of Life and Health Industry, University of Chinese Academy of Sciences, Ningbo, 315000, Zhejiang, China
| | - Jinni Jiang
- Department of Thoracic Surgery, Ningbo No.2 Hospital, Ningbo, 315010, Zhejiang, China
- Ningbo Institute of Life and Health Industry, University of Chinese Academy of Sciences, Ningbo, 315000, Zhejiang, China
| | - Xiaofang Wang
- Ningbo Institute of Life and Health Industry, University of Chinese Academy of Sciences, Ningbo, 315000, Zhejiang, China
| | - Xuejie Yang
- Ningbo Institute of Life and Health Industry, University of Chinese Academy of Sciences, Ningbo, 315000, Zhejiang, China
| | - Guofang Zhao
- Department of Thoracic Surgery, Ningbo No.2 Hospital, Ningbo, 315010, Zhejiang, China.
| | - Ting Cai
- Department of Thoracic Surgery, Ningbo No.2 Hospital, Ningbo, 315010, Zhejiang, China.
- Ningbo Institute of Life and Health Industry, University of Chinese Academy of Sciences, Ningbo, 315000, Zhejiang, China.
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Wang T, Kyle AH, Baker JHE, Liu NA, Banáth JP, Minchinton AI. DNA-PK inhibition extends the therapeutic effects of Top2 poisoning to non-proliferating cells, increasing activity at a cost. Sci Rep 2023; 13:12429. [PMID: 37528151 PMCID: PMC10394067 DOI: 10.1038/s41598-023-39649-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 07/28/2023] [Indexed: 08/03/2023] Open
Abstract
Type II topoisomerase (Top2) poisoning therapy is used to treat a broad range of cancers via induction of double strand breaks (DSBs) in cells undergoing replication and transcription. Preventing the repair of DSBs via inhibition of DNA-PK, an inhibitor of non-homologous end-joining (NHEJ), increases cell kill with Top2 poisons and has led to the initiation of several clinical trials. To elucidate the cellular mechanisms leading to synergistic activity of dual DNA-PK/Top2 inhibition we looked at their effects in cycling versus non-cycling cells, in 3D spheroids and in xenograft models. Combined DNA-PK/Top2 inhibition was found to not only increase the cell kill in proliferating cells, the cell population that is typically most vulnerable to Top2 poisoning, but also in non-proliferative but transcriptionally active cells. This effect was observed in both cancer and normal tissue models, killing more cells than high concentrations of etoposide alone. The combination treatment delayed tumor growth in mice compared to Top2 poisoning alone, but also led to increased toxicity. These findings demonstrate sensitization of Top2β-expressing, non-cycling cells to Top2 poisoning by DNA-PK inhibition. Expansion of the target cell population of Top2 poison treatment to include non-proliferating cells via combination with DNA damage repair inhibitors has implications for efficacy and toxicity of these combinations, including for inhibitors of DNA-PK currently in clinical trial.
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Affiliation(s)
- Taixiang Wang
- Department of Integrative Oncology, BC Cancer Research Institute, 675 W 10th Ave, Vancouver, BC, V5Z 1L3, Canada
| | - Alastair H Kyle
- Department of Integrative Oncology, BC Cancer Research Institute, 675 W 10th Ave, Vancouver, BC, V5Z 1L3, Canada
| | - Jennifer H E Baker
- Department of Integrative Oncology, BC Cancer Research Institute, 675 W 10th Ave, Vancouver, BC, V5Z 1L3, Canada
| | - Nannan A Liu
- Department of Integrative Oncology, BC Cancer Research Institute, 675 W 10th Ave, Vancouver, BC, V5Z 1L3, Canada
| | - Judit P Banáth
- Department of Integrative Oncology, BC Cancer Research Institute, 675 W 10th Ave, Vancouver, BC, V5Z 1L3, Canada
| | - Andrew I Minchinton
- Department of Integrative Oncology, BC Cancer Research Institute, 675 W 10th Ave, Vancouver, BC, V5Z 1L3, Canada.
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Lomov NA, Viushkov VS, Rubtsov MA. Mechanisms of Secondary Leukemia Development Caused by Treatment with DNA Topoisomerase Inhibitors. BIOCHEMISTRY. BIOKHIMIIA 2023; 88:892-911. [PMID: 37751862 DOI: 10.1134/s0006297923070040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 04/14/2023] [Accepted: 04/20/2023] [Indexed: 09/28/2023]
Abstract
Leukemia is a blood cancer originating in the blood and bone marrow. Therapy-related leukemia is associated with prior chemotherapy. Although cancer therapy with DNA topoisomerase II inhibitors is one of the most effective cancer treatments, its side effects include development of secondary leukemia characterized by the chromosomal rearrangements affecting AML1 or MLL genes. Recurrent chromosomal translocations in the therapy-related leukemia differ from chromosomal rearrangements associated with other neoplasias. Here, we reviewed the factors that drive chromosomal translocations induced by cancer treatment with DNA topoisomerase II inhibitors, such as mobility of ends of double-strand DNA breaks formed before the translocation and gain of function of fusion proteins generated as a result of translocation.
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Affiliation(s)
- Nikolai A Lomov
- Department of Molecular Biology, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia.
| | - Vladimir S Viushkov
- Department of Molecular Biology, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - Mikhail A Rubtsov
- Department of Molecular Biology, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
- Department of Biochemistry, Center for Industrial Technologies and Entrepreneurship Sechenov First Moscow State Medical University (Sechenov University), Moscow, 119435, Russia
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4
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Van Ravenstein SX, Mehta KP, Kavlashvili T, Byl JAW, Zhao R, Osheroff N, Cortez D, Dewar JM. Topoisomerase II poisons inhibit vertebrate DNA replication through distinct mechanisms. EMBO J 2022; 41:e110632. [PMID: 35578785 PMCID: PMC9194788 DOI: 10.15252/embj.2022110632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 04/25/2022] [Accepted: 04/28/2022] [Indexed: 11/09/2022] Open
Abstract
Topoisomerase II (TOP2) unlinks chromosomes during vertebrate DNA replication. TOP2 "poisons" are widely used chemotherapeutics that stabilize TOP2 complexes on DNA, leading to cytotoxic DNA breaks. However, it is unclear how these drugs affect DNA replication, which is a major target of TOP2 poisons. Using Xenopus egg extracts, we show that the TOP2 poisons etoposide and doxorubicin both inhibit DNA replication through different mechanisms. Etoposide induces TOP2-dependent DNA breaks and TOP2-dependent fork stalling by trapping TOP2 behind replication forks. In contrast, doxorubicin does not lead to appreciable break formation and instead intercalates into parental DNA to stall replication forks independently of TOP2. In human cells, etoposide stalls forks in a TOP2-dependent manner, while doxorubicin stalls forks independently of TOP2. However, both drugs exhibit TOP2-dependent cytotoxicity. Thus, etoposide and doxorubicin inhibit DNA replication through distinct mechanisms despite shared genetic requirements for cytotoxicity.
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Affiliation(s)
| | - Kavi P Mehta
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Tamar Kavlashvili
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Jo Ann W Byl
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Runxiang Zhao
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Neil Osheroff
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA.,Department of Medicine (Hematology/Oncology), Vanderbilt University School of Medicine, Nashville, TN, USA
| | - David Cortez
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - James M Dewar
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
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Swan RL, Cowell IG, Austin CA. Mechanisms to repair stalled Topoisomerase II-DNA covalent complexes. Mol Pharmacol 2021; 101:24-32. [PMID: 34689119 DOI: 10.1124/molpharm.121.000374] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 10/11/2021] [Indexed: 11/22/2022] Open
Abstract
DNA topoisomerases regulate the topological state of DNA, relaxing DNA supercoils and resolving catenanes and knots that result from biological processes such as transcription and replication. DNA topoisomerase II (TOP2) enzymes achieve this by binding DNA and introducing an enzyme-bridged DNA double-strand break (DSB) where each protomer of the dimeric enzyme is covalently attached to the 5' end of the cleaved DNA via an active site tyrosine phosphodiester linkage. The enzyme then passes a second DNA duplex though the DNA break, before religation and release of the enzyme. However, this activity is potentially hazardous to the cell, as failure to complete religation leads to persistent TOP2 protein-DNA covalent complexes which are cytotoxic. Indeed, this property of topoisomerase has been exploited in cancer therapy in the form of topoisomerase poisons which block the religation stage of the reaction cycle, leading to an accumulation of topoisomerase-DNA adducts. A number of parallel cellular processes have been identified that lead to removal of these covalent TOP2-DNA complexes facilitating repair of the resulting protein-free DSB by standard DNA repair pathways. These pathways presumably arose to repair spontaneous stalled or poisoned TOP2-DNA complexes, but understanding their mechanisms also has implications for cancer therapy, particularly resistance to anti-cancer TOP2 poisons and the genotoxic side effects of these drugs. Here we review recent progress in the understanding of the processing to TOP2 DNA covalent complexes., The basic components and mechanisms plus the additional layer of complexity posed by the post-translational modifications that modulate these pathways. Significance Statement Multiple pathways have been reported for removal and repair of TOP2-DNA covalent complexes to ensure the timely and efficient repair of TOP2-DNA covalent adducts to protect the genome. Post-translational modifications such as ubiquitination and SUMOylation are involved in the regulation of TOP2-DNA complex repair. Small molecule inhibitors of these post translational modifications may help to improve outcomes of TOP2 poison chemotherapy, for example by increasing TOP2 poison cytotoxicity and reducing genotoxicity, but this remains to be determined.
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Affiliation(s)
- Rebecca L Swan
- Biosciences Institute, Newcastle University, United Kingdom
| | - Ian G Cowell
- Institute for Cell and Molecular Biosciences, Newcastle University, United Kingdom
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6
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Ma Y, North BJ, Shu J. Regulation of topoisomerase II stability and activity by ubiquitination and SUMOylation: clinical implications for cancer chemotherapy. Mol Biol Rep 2021; 48:6589-6601. [PMID: 34476738 DOI: 10.1007/s11033-021-06665-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 08/17/2021] [Indexed: 12/09/2022]
Abstract
DNA topoisomerases II (TOP2) are peculiar enzymes (TOP2α and TOP2β) that modulate the conformation of DNA by momentarily breaking double-stranded DNA to allow another strand to pass through, and then rejoins the DNA phosphodiester backbone. TOP2α and TOP2β play vital roles in nearly all events involving DNA metabolism, including DNA transcription, replication, repair, and chromatin remodeling. Beyond these vital functions, TOP2 enzymes are therapeutic targets for various anticancer drugs, termed TOP2 poisons, such as teniposide, etoposide, and doxorubicin. These drugs exert their antitumor activity by inhibiting the activity of TOP2-DNA cleavage complexes (TOP2ccs) containing DNA double-strand breaks (DSBs), subsequently leading to the degradation of TOP2 by the 26S proteasome, thereby exposing the DSBs and eliciting a DNA damage response. Failure of the DSBs to be appropriately repaired leads to genomic instability. Due to this mechanism, patients treated with TOP2-based drugs have a high incidence of secondary malignancies and cardiotoxicity. While the cytotoxicity associated with TOP2 poisons appears to be TOP2α-dependent, the DNA sequence rearrangements and formation of DSBs appear to be mediated primarily through TOP2β inhibition, likely due to the differential degradation patterns of TOP2α and TOP2β. Research over the past few decades has shown that under various conditions, the ubiquitin-proteasome system (UPS) and the SUMOylation pathway are primarily responsible for regulating the stability and activity of TOP2 and are therefore critical regulators of the therapeutic effect of TOP2-targeting drugs. In this review, we summarize the current progress on the regulation of TOP2α and TOP2β by ubiquitination and SUMOylation. By fully elucidating the basic biology of these essential and complex molecular mechanisms, better strategies may be developed to improve the therapeutic efficacy of TOP2 poisons and minimize the risks of therapy-related secondary malignancy.
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Affiliation(s)
- Ying Ma
- Department of Medical Oncology, The First Affiliated Hospital of Zhejiang University, Hangzhou, 310029, China
- Zhejiang University School of Medicine, Hangzhou, 310029, China
| | - Brian J North
- Biomedical Sciences Department, Creighton University School of Medicine, 2500 California Plaza, Omaha, NE, 68178, USA.
| | - Jianfeng Shu
- HwaMei Hospital, University of Chinese Academy of Sciences, Ningbo, 315010, China.
- Ningbo Institute of Life and Health Industry, University of Chinese Academy of Sciences, Ningbo, 315020, China.
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Qiao W, Huang P, Wang X, Meng L. Susceptibility to DNA damage caused by abrogation of Rad54 homolog B: A putative mechanism for chemically induced cleft palate. Toxicology 2021; 456:152772. [PMID: 33823233 DOI: 10.1016/j.tox.2021.152772] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 03/25/2021] [Accepted: 03/31/2021] [Indexed: 11/24/2022]
Abstract
Exposure to environmental toxicants such as all-trans retinoic acid (atRA) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) may cause cleft palate (CP), which process is related to DNA damage. Rad54B, an important DNA damage repaired protein, has been proved to be associated with non-syndromic cleft lip with palate (NSCLP). In the present study, we sought to clarify the role of Rad54B in palatal development and environment-induced CP. atRA (100 mg/kg) and TCDD (40 μg/kg) were used to induce CP in mice (C57BL/6 J mice). In this study, mouse embryonic heads were collected on embryonic day (E) 13.5∼16.5. The expression level of DNA repair protein Rad54 homolog B (Rad54B) was significantly decreased while those of the DNA double-strand breaks (DSBs) marker γ-H2A.X, apoptosis marker caspase-3 and p53 were significantly increased in the palatal shelves upon exposure to atRA and TCDD relative to the control. Primary mouse embryonic palatal mesenchymal cells (MEPMs) were cultured and transfected with siRNA or adenovirus in vitro to knock down or increase the level of Rad54B. Rad54B knockdown resulted in increased cellular S-phase arrest and apoptosis as well as decreased cell proliferation. Rad54B overexpression also increased apoptosis and reduced cell proliferation. Western blotting was used to detect the level of γ-H2A.X in transfected cells stimulated with etoposide (ETO, a DSBs inducer), and after 5 μM ETO stimulation of transfected MEPMs, the expression of γ-H2A.X was increased in Rad54B-knockdown cells. The expression of Mdm2, Mdmx and p53 with changes in Rad54B was also detected and coimmunoprecipitation was performed to analyze the combination of Mdm2 and p53 when Rad54B was changed in MEPMs. Knockdown of Rad54B inhibited the expression of Mdm2 and Mdmx, while the level of p53 increased. The coimmunoprecipitation results showed a decreased combination of Mdm2 and p53 when Rad54B was knocked down. Therefore, Rad54B can regulate the cell cycle, proliferation, and apoptosis of MEPMs. The loss of Rad54B increased the sensitivity of MEPMs to DSBs inducers, promoted apoptosis, and suppressed the proliferation of MEPMs by inhibiting the degradation of p53. Taken together, these findings suggest that Rad54B may play a key regulatory role in environment-induced CP.
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Affiliation(s)
- Weiwei Qiao
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, Hubei, PR China
| | - Pei Huang
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, Hubei, PR China
| | - Xinhuan Wang
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, Hubei, PR China
| | - Liuyan Meng
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, Hubei, PR China.
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8
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Xiang C, Wu X, Zhao Z, Feng X, Bai X, Liu X, Zhao J, Takeda S, Qing Y. Nonhomologous end joining and homologous recombination involved in luteolin-induced DNA damage in DT40 cells. Toxicol In Vitro 2020; 65:104825. [PMID: 32169435 DOI: 10.1016/j.tiv.2020.104825] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 02/08/2020] [Accepted: 03/08/2020] [Indexed: 02/05/2023]
Abstract
Luteolin (3',4',5,7-tetrahydroxyflavone), a naturally occurring flavonoid, has been shown to have anticancer activity in many types of cancer cell lines. The anticancer capacity of luteolin may be related to its ability to induce DNA double-strand breaks (DSBs). Here, we used DT40 cells to determine whether nonhomologous end joining (NHEJ) and homologous recombination (HR) are involved in the repair mechanism of luteolin-induced DNA damage. Cells defective in Ku70 (an enzyme associated with NHEJ) or Rad54 (an enzyme essential for HR) were hypersensitive and presented more apoptosis in response to luteolin. Moreover, the sensitivity and apoptosis of Ku70-/- and Rad54-/- cells were associated with increased DNA damage when the numbers of γ-H2AX foci and chromosomal aberrations (CAs) were compared with those from WT cells. Additionally, after treatment with luteolin, Ku70-/- cells presented more Top2 covalent cleavage complexes (Top2cc). These results indicated that luteolin induced DSBs in DT40 cells and demonstrated that both NHEJ and HR participated in the repair of luteolin-induced DSBs, which might be related to the inhibition of topoisomerases. These results imply that simultaneous inhibition of NHEJ and HR with luteolin treatment would provide a powerful protocol in cancer chemotherapy.
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Affiliation(s)
- Cuifang Xiang
- Department of Pharmacology, Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan, China
| | - Xiaohua Wu
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Zilu Zhao
- Department of Pharmacology, Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan, China
| | - Xiaoyu Feng
- Department of Pharmacology, Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan, China
| | - Xin Bai
- Department of Pharmacology, Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan, China
| | - Xin Liu
- Department of Pharmacology, Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan, China
| | - Jingxia Zhao
- Department of Pharmacology, Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan, China
| | - Shunichi Takeda
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yong Qing
- Department of Pharmacology, Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan, China.
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9
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SCF β-TrCP-mediated degradation of TOP2β promotes cancer cell survival in response to chemotherapeutic drugs targeting topoisomerase II. Oncogenesis 2020; 9:8. [PMID: 32015321 PMCID: PMC6997367 DOI: 10.1038/s41389-020-0196-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 12/10/2019] [Accepted: 01/10/2020] [Indexed: 12/17/2022] Open
Abstract
Topoisomerase II (TOP2)-targeting anticancer chemotherapeutic drugs, termed TOP2 poisons, are widely used and effective in the clinic by stabilizing TOP2-DNA covalent complexes to induce DNA double-strand breaks (DSBs) and ultimately, cause cell death. The stabilized TOP2-DNA complex is known to be degraded by proteasome, whereas the underlying mechanism for instant TOP2β degradation in response to TOP2 poisons and the subsequent biological consequence remain elusive. Here, we reported that TOP2 poison-induced TOP2β degradation is mediated by SCFβ-TrCP ubiquitin ligase. Specifically, DNA damage signal, triggered by teniposide (VM-26) treatment, activates ATM, cooperating with CK1 to phosphorylate TOP2β on Ser1134 and Ser1130, respectively, in a canonical degron motif to facilitate β-TrCP binding and subsequent degradation. Inactivation of ATM, CK1 or SCFβ-TrCP by small molecular inhibitors or genetic knockdown/knockout abrogates TOP2β degradation. Biologically, blockage of TOP2β degradation in combination with VM-26 treatment impairs DNA damage response and repair, leading to an accelerated cell death via apoptosis. Thus, it appears that TOP2β degradation is a cellular defensive mechanism to facilitate the exposure of DSBs to trigger DNA damage response and repair. Collectively, our findings reveal a new strategy to improve the efficacy of TOP2 poisons in combination with small-molecule inhibitors against TOP2β degradation.
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10
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Ahmed SM, Dröge P. Oncofetal HMGA2 attenuates genotoxic damage induced by topoisomerase II target compounds through the regulation of local DNA topology. Mol Oncol 2019; 13:2062-2078. [PMID: 31271486 PMCID: PMC6763970 DOI: 10.1002/1878-0261.12541] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 06/26/2019] [Accepted: 07/03/2019] [Indexed: 12/26/2022] Open
Abstract
Rapidly dividing cells maintain chromatin supercoiling homeostasis via two specialized classes of enzymes, DNA topoisomerase type 1 and 2 (TOP1/2). Several important anticancer drugs perturb this homeostasis by targeting TOP1/2, thereby generating genotoxic DNA damage. Our recent studies indicated that the oncofetal chromatin structuring high‐mobility group AT‐hook 2 (HMGA2) protein plays an important role as a DNA replication fork chaperone in coping with DNA topological ramifications that occur during replication stress, both genomewide and at fragile sites such as subtelomeres. Intriguingly, a recent large‐scale clinical study identified HMGA2 expression as a sole predicting marker for relapse and poor clinical outcomes in 350 acute myeloid leukemia (AML) patients receiving combinatorial treatments that targeted TOP2 and replicative DNA synthesis. Here, we demonstrate that HMGA2 significantly enhanced the DNA supercoil relaxation activity of the drug target TOP2A and that this activator function is mechanistically linked to HMGA2's known ability to constrain DNA supercoils within highly compacted ternary complexes. Furthermore, we show that HMGA2 significantly reduced genotoxic DNA damage in each tested cancer cell model during treatment with the TOP2A poison etoposide or the catalytic TOP2A inhibitor merbarone. Taken together with the recent clinical data obtained with AML patients targeted with TOP2 poisons, our study suggests a novel mechanism of cancer chemoresistance toward combination therapies administering TOP2 poisons or inhibitors. We therefore strongly argue for the future implementation of trials of HMGA2 expression profiling to stratify patients before finalizing clinical treatment regimes.
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Affiliation(s)
- Syed Moiz Ahmed
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Peter Dröge
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
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11
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Hegedüs É, Kókai E, Nánási P, Imre L, Halász L, Jossé R, Antunovics Z, Webb MR, El Hage A, Pommier Y, Székvölgyi L, Dombrádi V, Szabó G. Endogenous single-strand DNA breaks at RNA polymerase II promoters in Saccharomyces cerevisiae. Nucleic Acids Res 2019; 46:10649-10668. [PMID: 30445637 PMCID: PMC6237785 DOI: 10.1093/nar/gky743] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 08/16/2018] [Indexed: 12/12/2022] Open
Abstract
Molecular combing and gel electrophoretic studies revealed endogenous nicks with free 3'OH ends at ∼100 kb intervals in the genomic DNA (gDNA) of unperturbed and G1-synchronized Saccharomyces cerevisiae cells. Analysis of the distribution of endogenous nicks by Nick ChIP-chip indicated that these breaks accumulated at active RNA polymerase II (RNAP II) promoters, reminiscent of the promoter-proximal transient DNA breaks of higher eukaryotes. Similar periodicity of endogenous nicks was found within the ribosomal rDNA cluster, involving every ∼10th of the tandemly repeated 9.1 kb units of identical sequence. Nicks were mapped by Southern blotting to a few narrow regions within the affected units. Three of them were overlapping the RNAP II promoters, while the ARS-containing IGS2 region was spared of nicks. By using a highly sensitive reverse-Southwestern blot method to map free DNA ends with 3'OH, nicks were shown to be distinct from other known rDNA breaks and linked to the regulation of rDNA silencing. Nicks in rDNA and the rest of the genome were typically found at the ends of combed DNA molecules, occasionally together with R-loops, comprising a major pool of vulnerable sites that are connected with transcriptional regulation.
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Affiliation(s)
- Éva Hegedüs
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Endre Kókai
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Péter Nánási
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - László Imre
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - László Halász
- MTA-DE Momentum Genome Architecture and Recombination Research Group, Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Rozenn Jossé
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute (CCR-NCI), NIH, Bethesda, MD, USA
| | - Zsuzsa Antunovics
- Department of Genetics and Applied Microbiology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | | | - Aziz El Hage
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Yves Pommier
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute (CCR-NCI), NIH, Bethesda, MD, USA
| | - Lóránt Székvölgyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,MTA-DE Momentum Genome Architecture and Recombination Research Group, Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Viktor Dombrádi
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Gábor Szabó
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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12
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Abstract
The Elg1protein forms an RFC-like complex in charge of unloading PCNA from chromatin during DNA replication and repair. Mutations in the ELG1 gene caused genomic instability in all organisms tested and cancer in mammals. Here we show that Elg1 plays a role in the induction of the DNA damage checkpoint, a cellular response to DNA damage. We show that this defect is due to a defect in the signal amplification process during induction. Thus, cells coordinate the cell's response and the PCNA unloading through the activity of Elg1. The PCNA (proliferating cell nuclear antigen) ring plays central roles during DNA replication and repair. The yeast Elg1 RFC-like complex (RLC) is the principal unloader of chromatin-bound PCNA and thus plays a central role in maintaining genome stability. Here we identify a role for Elg1 in the unloading of PCNA during DNA damage. Using DNA damage checkpoint (DC)-inducible and replication checkpoint (RC)-inducible strains, we show that Elg1 is essential for eliciting the signal in the DC branch. In the absence of Elg1 activity, the Rad9 (53BP1) and Dpb11 (TopBP1) adaptor proteins are recruited but fail to be phosphorylated by Mec1 (ATR), resulting in a lack of checkpoint activation. The chromatin immunoprecipitation of PCNA at the Lac operator sites reveals that accumulated local PCNA influences the checkpoint activation process in elg1 mutants. Our data suggest that Elg1 participates in a mechanism that may coordinate PCNA unloading during DNA repair with DNA damage checkpoint induction.
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13
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Shen X, Gates KS. Enzyme-Activated Generation of Reactive Oxygen Species from Heterocyclic N-Oxides under Aerobic and Anaerobic Conditions and Its Relevance to Hypoxia-Selective Prodrugs. Chem Res Toxicol 2019; 32:348-361. [PMID: 30817135 DOI: 10.1021/acs.chemrestox.9b00036] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Enzymatic one-electron reduction of heterocyclic N-oxides can lead to the intracellular generation of reactive oxygen species via several different chemical pathways. These reactions may be relevant to hypoxia-selective anticancer drugs, antimicrobial agents, and unwanted toxicity of heterocylic nitrogen compounds.
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14
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Lamarche BJ, Orazio NI, Goben B, Meisenhelder J, You Z, Weitzman MD, Hunter T. Repair of protein-linked DNA double strand breaks: Using the adenovirus genome as a model substrate in cell-based assays. DNA Repair (Amst) 2018; 74:80-90. [PMID: 30583959 DOI: 10.1016/j.dnarep.2018.12.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 12/07/2018] [Accepted: 12/07/2018] [Indexed: 11/29/2022]
Abstract
The DNA double strand breaks (DSBs) created during meiotic recombination and during some types of chemotherapy contain protein covalently attached to their 5' termini. Removal of the end-blocking protein is a prerequisite to DSB processing by non-homologous end-joining or homologous recombination. One mechanism for removing the protein involves CtIP-stimulated Mre11-catalyzed nicking of the protein-linked strand distal to the DSB terminus, releasing the end-blocking protein while it remains covalently attached to an oligonucleotide. Much of what is known about this repair process has recently been deciphered through in vitro reconstitution studies. We present here a novel model system based on adenovirus (Ad), which contains the Ad terminal protein covalently linked to the 5' terminus of its dsDNA genome, for studying the repair of 5' protein-linked DSBs in vivo. It was previously shown that the genome of Ad mutants that lack early region 4 (E4) can be joined into concatemers in vivo, suggesting that the Ad terminal protein had been removed from the genome termini prior to ligation. Here we show that during infection with the E4-deleted Ad mutant dl1004, the Ad terminal protein is removed in a manner that recapitulates removal of end-blocking proteins from cellular DSBs. In addition to displaying a dependence on CtIP, and Mre11 acting as the endonuclease, the protein-linked oligonucleotides that are released from the viral genome are similar in size to the oligos that remain attached to Spo11 and Top2 after they are removed from the 5' termini of DSBs during meiotic recombination and etoposide chemotherapy, respectively. The single nucleotide resolution that is possible with this assay, combined with the single sequence context in which the lesion is presented, make it a useful tool for further refining our mechanistic understanding of how blocking proteins are removed from the 5' termini of DSBs.
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Affiliation(s)
- Brandon J Lamarche
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, California, 92037, USA; Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California, 92037, USA
| | - Nicole I Orazio
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, California, 92037, USA
| | - Brittany Goben
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California, 92037, USA
| | - Jill Meisenhelder
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California, 92037, USA
| | - Zhongsheng You
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
| | - Matthew D Weitzman
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, California, 92037, USA.
| | - Tony Hunter
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California, 92037, USA.
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15
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Drissi R, Chauvin A, McKenna A, Lévesque D, Blais-Brochu S, Jean D, Boisvert FM. Destabilization of the MiniChromosome Maintenance (MCM) complex modulates the cellular response to DNA double strand breaks. Cell Cycle 2018; 17:2593-2609. [PMID: 30516086 PMCID: PMC6300108 DOI: 10.1080/15384101.2018.1553336] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
DNA replication during S phase involves thousands of replication forks that must be coordinated to ensure that every DNA section is replicated only once. The minichromosome maintenance proteins, MCM2 to MCM7, form a heteromeric DNA helicase required for both the initiation and elongation of DNA replication. Although only two DNA helicase activities are necessary to establish a bidirectional replication fork from each replication origin, a large excess of MCM complexes is amassed and distributed along the chromatin. The function of the additional MCM complexes is not well understood, as most are displaced from the DNA during the S-phase, apparently without playing an active role in DNA replication. DNA damage response (DDR) kinases activated by stalled forks prevent the replication machinery from being activated, indicating a tight relationship between DDR and DNA replication. To investigate the role of MCM proteins in the cellular response to DNA damage, we used shRNA targeting MCM2 or MCM3 to determine the impact of a reduction in MCM complex. The alteration of MCM proteins induced a change in the activation of key factors of the DDR in response to Etoposide treatment. Etoposide-induced DNA damage affected the phosphorylation of γ-H2AX, CHK1 and CHK2 without affecting cell viability. Using assays measuring homologous recombination (HR) and non-homologous end-joining (NHEJ), we identified a decrease in both HR and NHEJ associated with a decrease in MCM complex.
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Affiliation(s)
- Romain Drissi
- a Department of Anatomy and Cell Biology , Université de Sherbrooke , 3201 Jean-Mignaul, Sherbrooke , Québec , Canada
| | - Anaïs Chauvin
- a Department of Anatomy and Cell Biology , Université de Sherbrooke , 3201 Jean-Mignaul, Sherbrooke , Québec , Canada
| | - Alyson McKenna
- a Department of Anatomy and Cell Biology , Université de Sherbrooke , 3201 Jean-Mignaul, Sherbrooke , Québec , Canada
| | - Dominique Lévesque
- a Department of Anatomy and Cell Biology , Université de Sherbrooke , 3201 Jean-Mignaul, Sherbrooke , Québec , Canada
| | - Simon Blais-Brochu
- a Department of Anatomy and Cell Biology , Université de Sherbrooke , 3201 Jean-Mignaul, Sherbrooke , Québec , Canada
| | - Dominique Jean
- a Department of Anatomy and Cell Biology , Université de Sherbrooke , 3201 Jean-Mignaul, Sherbrooke , Québec , Canada
| | - François-Michel Boisvert
- a Department of Anatomy and Cell Biology , Université de Sherbrooke , 3201 Jean-Mignaul, Sherbrooke , Québec , Canada
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16
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Austin CA, Lee KC, Swan RL, Khazeem MM, Manville CM, Cridland P, Treumann A, Porter A, Morris NJ, Cowell IG. TOP2B: The First Thirty Years. Int J Mol Sci 2018; 19:ijms19092765. [PMID: 30223465 PMCID: PMC6163646 DOI: 10.3390/ijms19092765] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 09/07/2018] [Accepted: 09/11/2018] [Indexed: 12/19/2022] Open
Abstract
Type II DNA topoisomerases (EC 5.99.1.3) are enzymes that catalyse topological changes in DNA in an ATP dependent manner. Strand passage reactions involve passing one double stranded DNA duplex (transported helix) through a transient enzyme-bridged break in another (gated helix). This activity is required for a range of cellular processes including transcription. Vertebrates have two isoforms: topoisomerase IIα and β. Topoisomerase IIβ was first reported in 1987. Here we review the research on DNA topoisomerase IIβ over the 30 years since its discovery.
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Affiliation(s)
- Caroline A Austin
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
| | - Ka C Lee
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
| | - Rebecca L Swan
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
| | - Mushtaq M Khazeem
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
| | - Catriona M Manville
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
| | - Peter Cridland
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
| | - Achim Treumann
- NUPPA, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
| | - Andrew Porter
- NUPPA, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
| | - Nick J Morris
- School of Biomedical Sciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
| | - Ian G Cowell
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
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17
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Liu N, Niu S, Cao XR, Cheng JQ, Gao SY, Yu XJ, Wang HD, Dong CS, He XY. Let-7b regulates alpaca hair growth by downregulating ectodysplasin A. Mol Med Rep 2018; 17:4688-4694. [PMID: 29344666 DOI: 10.3892/mmr.2018.8442] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Accepted: 08/24/2017] [Indexed: 11/06/2022] Open
Abstract
Hypohidrotic ectodermal dysplasia (HED), also known as anhidrotic ectodermal dysplasia, is characterized by the clinical manifestations of less sweat or no sweat, sparse or no hair, tooth agenesis and/or abnormal tooth morphology. The characteristics of alpaca ear hair differ from the back hair. The ectodysplasin A (EDA) signaling pathway has a regulatory effect on skin development and hair growth. The aim of the present study was to study the effects of EDA on alpaca hair growth by examining the mRNA and protein expression levels of EDA in alpaca ear and back skin by reverse transcription‑quantitative polymerase chain reaction and western blot analysis, respectively. Results indicated that EDA expression was higher in the ear skin compared with the back skin. The expression levels of let‑7b in the skin of healthy alpacas varies; the difference between let‑7b expression levels of the ear and back have been reported to be >2‑fold, suggesting a role for let‑7b in the development of adult alpaca skin and hair follicles. A dual‑luciferase reporter vector was constructed to verify the targeting relationship between microRNA let‑7b and EDA, and the results revealed that EDA was a target gene of let‑7b. Alpaca skin fibroblasts were transfected with a let‑7b eukaryotic expression vector to investigate the regulatory relationship between let‑7b and EDA. The expression of EDA was decreased in the transfected group; immunocytochemical results demonstrated that the EDA protein was abundantly expressed in the fibroblast cytoplasm. EDA protein expression was weaker in the transfected cells than in the untransfected cells. These results suggested that EDA may serve a role in alpaca hair growth and is probably a target gene of let‑7b; let‑7b downregulated EDA mRNA and protein expressions, which suggested that let‑7b may regulate alpaca hair growth. These conclusions suggested that let‑7b may be associated with HED.
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Affiliation(s)
- Ning Liu
- Alpaca Bioengineering Laboratory, College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi 030801, P.R. China
| | - Shu Niu
- Alpaca Bioengineering Laboratory, College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi 030801, P.R. China
| | - Xiao-Rui Cao
- Alpaca Bioengineering Laboratory, College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi 030801, P.R. China
| | - Jia-Qi Cheng
- Alpaca Bioengineering Laboratory, College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi 030801, P.R. China
| | - Shu-Yuan Gao
- Alpaca Bioengineering Laboratory, College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi 030801, P.R. China
| | - Xiu-Ju Yu
- Alpaca Bioengineering Laboratory, College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi 030801, P.R. China
| | - Hai-Dong Wang
- Alpaca Bioengineering Laboratory, College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi 030801, P.R. China
| | - Chang-Sheng Dong
- Alpaca Bioengineering Laboratory, College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi 030801, P.R. China
| | - Xiao-Yan He
- Alpaca Bioengineering Laboratory, College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi 030801, P.R. China
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18
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Gendarme M, Baumann J, Ignashkova TI, Lindemann RK, Reiling JH. Image-based drug screen identifies HDAC inhibitors as novel Golgi disruptors synergizing with JQ1. Mol Biol Cell 2017; 28:3756-3772. [PMID: 29074567 PMCID: PMC5739293 DOI: 10.1091/mbc.e17-03-0176] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 10/17/2017] [Accepted: 10/17/2017] [Indexed: 12/12/2022] Open
Abstract
The Golgi apparatus is increasingly recognized as a major hub for cellular signaling and is involved in numerous pathologies, including neurodegenerative diseases and cancer. The study of Golgi stress-induced signaling pathways relies on the selectivity of the available tool compounds of which currently only a few are known. To discover novel Golgi-fragmenting agents, transcriptomic profiles of cells treated with brefeldin A, golgicide A, or monensin were generated and compared with a database of gene expression profiles from cells treated with other bioactive small molecules. In parallel, a phenotypic screen was performed for compounds that alter normal Golgi structure. Histone deacetylase (HDAC) inhibitors and DNA-damaging agents were identified as novel Golgi disruptors. Further analysis identified HDAC1/HDAC9 as well as BRD8 and DNA-PK as important regulators of Golgi breakdown mediated by HDAC inhibition. We provide evidence that combinatorial HDACi/(+)-JQ1 treatment spurs synergistic Golgi dispersal in several cancer cell lines, pinpointing a possible link between drug-induced toxicity and Golgi morphology alterations.
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Affiliation(s)
| | - Jan Baumann
- BioMed X Innovation Center, 69120 Heidelberg, Germany
| | | | - Ralph K Lindemann
- Translational Innovation Platform Oncology, Merck Biopharma, Merck KGaA, 64293 Darmstadt, Germany
| | - Jan H Reiling
- BioMed X Innovation Center, 69120 Heidelberg, Germany
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19
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Abstract
In this issue of Molecular Cell, Wei et al. (2017) report how a DNA translocase uses SUMO as a cue to save Top2 from ubiquitin-mediated degradation and to minimize DNA breaks, thus providing insights into the SUMO and ubiquitin interplay in genome maintenance.
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Affiliation(s)
- Nalini Dhingra
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Xiaolan Zhao
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
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20
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Wei Y, Diao LX, Lu S, Wang HT, Suo F, Dong MQ, Du LL. SUMO-Targeted DNA Translocase Rrp2 Protects the Genome from Top2-Induced DNA Damage. Mol Cell 2017; 66:581-596.e6. [PMID: 28552615 DOI: 10.1016/j.molcel.2017.04.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 03/27/2017] [Accepted: 04/24/2017] [Indexed: 02/07/2023]
Abstract
The action of DNA topoisomerase II (Top2) creates transient DNA breaks that are normally concealed inside Top2-DNA covalent complexes. Top2 poisons, including ubiquitously present natural compounds and clinically used anti-cancer drugs, trap Top2-DNA complexes. Here, we show that cells actively prevent Top2 degradation to avoid the exposure of concealed DNA breaks. A genome-wide screen revealed that fission yeast cells lacking Rrp2, an Snf2-family DNA translocase, are strongly sensitive to Top2 poisons. Loss of Rrp2 enhances SUMOylation-dependent ubiquitination and degradation of Top2, which in turn increases DNA damage at sites where Top2-DNA complexes are trapped. Rrp2 possesses SUMO-binding ability and prevents excessive Top2 degradation by competing against the SUMO-targeted ubiquitin ligase (STUbL) for SUMO chain binding and by displacing SUMOylated Top2 from DNA. The budding yeast homolog of Rrp2, Uls1, plays a similar role, indicating that this genome protection mechanism is widely employed, a finding with implications for cancer treatment.
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Affiliation(s)
- Yi Wei
- National Institute of Biological Sciences, Beijing 102206, China
| | - Li-Xue Diao
- National Institute of Biological Sciences, Beijing 102206, China
| | - Shan Lu
- National Institute of Biological Sciences, Beijing 102206, China
| | - Hai-Tao Wang
- National Institute of Biological Sciences, Beijing 102206, China
| | - Fang Suo
- National Institute of Biological Sciences, Beijing 102206, China
| | - Meng-Qiu Dong
- National Institute of Biological Sciences, Beijing 102206, China
| | - Li-Lin Du
- National Institute of Biological Sciences, Beijing 102206, China; Collaborative Innovation Center for Cancer Medicine, National Institute of Biological Sciences, Beijing 102206, China.
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