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Makinwa Y, Luo Y, Musich PR, Zou Y. Canonical and Noncanonical Functions of the BH3 Domain Protein Bid in Apoptosis, Oncogenesis, Cancer Therapeutics, and Aging. Cancers (Basel) 2024; 16:2199. [PMID: 38927905 PMCID: PMC11202167 DOI: 10.3390/cancers16122199] [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: 04/29/2024] [Revised: 06/05/2024] [Accepted: 06/09/2024] [Indexed: 06/28/2024] Open
Abstract
Effective cancer therapy with limited adverse effects is a major challenge in the medical field. This is especially complicated by the development of acquired chemoresistance. Understanding the mechanisms that underlie these processes remains a major effort in cancer research. In this review, we focus on the dual role that Bid protein plays in apoptotic cell death via the mitochondrial pathway, in oncogenesis and in cancer therapeutics. The BH3 domain in Bid and the anti-apoptotic mitochondrial proteins (Bcl-2, Bcl-XL, mitochondrial ATR) it associates with at the outer mitochondrial membrane provides us with a viable target in cancer therapy. We will discuss the roles of Bid, mitochondrial ATR, and other anti-apoptotic proteins in intrinsic apoptosis, exploring how their interaction sustains cellular viability despite the initiation of upstream death signals. The unexpected upregulation of this Bid protein in cancer cells can also be instrumental in explaining the mechanisms behind acquired chemoresistance. The stable protein associations at the mitochondria between tBid and anti-apoptotic mitochondrial ATR play a crucial role in maintaining the viability of cancer cells, suggesting a novel mechanism to induce cancer cell apoptosis by freeing tBid from the ATR associations at mitochondria.
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Affiliation(s)
- Yetunde Makinwa
- Department of Cell and Cancer Biology, University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA; (Y.M.); (Y.L.)
| | - Yibo Luo
- Department of Cell and Cancer Biology, University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA; (Y.M.); (Y.L.)
| | - Phillip R. Musich
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, USA;
| | - Yue Zou
- Department of Cell and Cancer Biology, University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA; (Y.M.); (Y.L.)
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2
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Akepogu J, Jakati S, Chaurasia S, Ramachandran C. Evidence for persistent UV-induced DNA damage and altered DNA damage response in xeroderma pigmentosa patient corneas. Exp Eye Res 2024; 243:109901. [PMID: 38641197 DOI: 10.1016/j.exer.2024.109901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 03/26/2024] [Accepted: 04/15/2024] [Indexed: 04/21/2024]
Abstract
Xeroderma pigmentosum (XP) is a rare genetic disorder characterized by injury to the ocular surface due to exposure to ultraviolet (UV) radiation. UV-induced damage in the cells leads to the formation of cyclobutane pyrimidine dimers (CPDs) and 6-4 pyrimidine-pyrimidone photoproducts that are repaired by the NER (Nucleotide Excision Repair) pathway. Mutations in the genes coding for NER proteins, as reported in XP patients, would lead to sub-optimal damage repair resulting in clinical signs varying from photo-keratitis to cancerous lesions on the ocular surface. Here, we aimed to provide evidence for the accumulation of DNA damage and activation of DNA repair pathway proteins in the corneal cells of patients with XP. Corneal buttons of patients who underwent penetrating keratoplasty were stained to quantify DNA damage and the presence of activated DNA damage response proteins (DDR) using specific antibodies. Positive staining for pH2A.X and thymidine dimers confirmed the presence of DNA damage in the corneal cells. Positive cells were found in both control corneas and XP samples however, unlike normal tissues, positive cells were found in all cell layers of XP samples indicating that these cells were sensitive to very low levels of UV. pH2A.X-positive cells were significantly more in XP corneas (p < 0.05) indicating the presence of double strand breaks in these tissues. A positive expression of phosphorylated-forms of DDR proteins was noted in XP corneas (unlike controls) such as ataxia telangiectasia mutated/Rad-3 related proteins (ATM/ATR), breast cancer-1 and checkpoint kinases-1 and -2. Nuclear localization of XPA was noted in XP samples which co-localized (calculated using Pearson's correlation) with pATM (0.9 ± 0.007) and pATR (0.6 ± 0.053). The increased presence of these in the nucleus confirms that unresolved DNA damage was accumulating in these cells thereby leading to prolonged activation of the damage response proteins. An increase in pp53 and TUNEL positive cells in the XP corneas indicated cell death likely driven by the p53 pathway. For comparison, cultured normal corneal epithelial cells were exposed to UV-radiation and stained for DDR proteins at 3, 6 and 24 h after irradiation to quantify the time taken by cells with intact DDR pathway to repair damage. These cells, when exposed to UV showed nuclear translocation of DDR proteins at 3 and 6 h which reduced significantly by 24 h confirming that the damaged DNA was being actively repaired leading to cell survival. The persistent presence of the DDR proteins in XP corneas indicates that damage is being actively recognized and DNA replication is stalled, thereby causing accumulation of damaged DNA leading to cell death, which would explain the cancer incidence and cell loss reported in these patients.
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Affiliation(s)
- Jacquelyn Akepogu
- Prof. Brien Holden Eye Research Centre, LV Prasad Eye Institute, Hyderabad, Telangana, India; Manipal Academy of Higher Education, Manipal, India
| | - Saumya Jakati
- Ophthalmic Pathology Laboratory, LV Prasad Eye Institute, Hyderabad, India
| | - Sunita Chaurasia
- The Cornea Institute, L V Prasad Eye Institute, Hyderabad, India
| | - Charanya Ramachandran
- Prof. Brien Holden Eye Research Centre, LV Prasad Eye Institute, Hyderabad, Telangana, India.
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3
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Biswas H, Makinwa Y, Zou Y. Novel Cellular Functions of ATR for Therapeutic Targeting: Embryogenesis to Tumorigenesis. Int J Mol Sci 2023; 24:11684. [PMID: 37511442 PMCID: PMC10380702 DOI: 10.3390/ijms241411684] [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: 07/07/2023] [Revised: 07/14/2023] [Accepted: 07/18/2023] [Indexed: 07/30/2023] Open
Abstract
The DNA damage response (DDR) is recognized as having an important role in cancer growth and treatment. ATR (ataxia telangiectasia mutated and Rad3-related) kinase, a major regulator of DDR, has shown significant therapeutic potential in cancer treatment. ATR inhibitors have shown anti-tumor effectiveness, not just as monotherapies but also in enhancing the effects of standard chemotherapy, radiation, and immunotherapy. The biological basis of ATR is examined in this review, as well as its functional significance in the development and therapy of cancer, and the justification for inhibiting this target as a therapeutic approach, including an assessment of the progress and status of previous decades' development of effective and selective ATR inhibitors. The current applications of these inhibitors in preclinical and clinical investigations as single medicines or in combination with chemotherapy, radiation, and immunotherapy are also fully reviewed. This review concludes with some insights into the many concerns highlighted or identified with ATR inhibitors in both the preclinical and clinical contexts, as well as potential remedies proposed.
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Affiliation(s)
| | | | - Yue Zou
- Department of Cell and Cancer Biology, College of Medicine and Life Sciences, University of Toledo, Toledo, OH 43614, USA; (H.B.); (Y.M.)
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4
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Krasikova YS, Lavrik OI, Rechkunova NI. The XPA Protein-Life under Precise Control. Cells 2022; 11:cells11233723. [PMID: 36496984 PMCID: PMC9739396 DOI: 10.3390/cells11233723] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 11/15/2022] [Accepted: 11/16/2022] [Indexed: 11/24/2022] Open
Abstract
Nucleotide excision repair (NER) is a central DNA repair pathway responsible for removing a wide variety of DNA-distorting lesions from the genome. The highly choreographed cascade of core NER reactions requires more than 30 polypeptides. The xeroderma pigmentosum group A (XPA) protein plays an essential role in the NER process. XPA interacts with almost all NER participants and organizes the correct NER repair complex. In the absence of XPA's scaffolding function, no repair process occurs. In this review, we briefly summarize our current knowledge about the XPA protein structure and analyze the formation of contact with its protein partners during NER complex assembling. We focus on different ways of regulation of the XPA protein's activity and expression and pay special attention to the network of post-translational modifications. We also discuss the data that is not in line with the currently accepted hypothesis about the functioning of the XPA protein.
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Affiliation(s)
- Yuliya S. Krasikova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Olga I. Lavrik
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
- Department of Natural Sciences, Novosibirsk State University, Novosibirsk 630090, Russia
| | - Nadejda I. Rechkunova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
- Correspondence:
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5
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Ahmed S, Alam W, Aschner M, Alsharif KF, Albrakati A, Saso L, Khan H. Natural products targeting the ATR-CHK1 signaling pathway in cancer therapy. Biomed Pharmacother 2022; 155:113797. [PMID: 36271573 PMCID: PMC9590097 DOI: 10.1016/j.biopha.2022.113797] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 09/29/2022] [Accepted: 10/02/2022] [Indexed: 11/19/2022] Open
Abstract
Cancer is one of the most severe medical conditions in the world, causing millions of deaths each year. Chemotherapy and radiotherapy are critical for treatment approaches, but both have numerous adverse health effects. Furthermore, the resistance of cancerous cells to anticancer medication leads to treatment failure. The rising burden of cancer requires novel efficacious treatment modalities. Natural remedies offer feasible alternative options against malignancy in contrast to available synthetic medication. Selective killing of cancer cells is privileged mainstream in cancer treatment, and targeted therapy represents the new tool with the potential to pursue this aim. The discovery of innovative therapies targeting essential components of DNA damage signaling and repair pathways such as ataxia telangiectasia mutated and Rad3 related Checkpoint kinase 1 (ATR-CHK1)has offered a possibility of significant therapeutic improvement in oncology. The activation and inhibition of this pathway account for chemopreventive and chemotherapeutic activity, respectively. Targeting this pathway can also aid to overcome the resistance of conventional chemo- or radiotherapy. This review enlightens the anticancer role of natural products by ATR-CHK1 activation and inhibition. Additionally, these compounds have been shown to have chemotherapeutic synergistic potential when used in combination with other anticancer drugs. Ideally, this review will trigger interest in natural products targeting ATR-CHK1 and their potential efficacy and safety as cancer lessening agents.
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Affiliation(s)
- Salman Ahmed
- Department of Pharmacognosy, Faculty of Pharmacy and Pharmaceutical Sciences, University of Karachi, Karachi 75270, Pakistan
| | - Waqas Alam
- Department of Pharmacy, Abdul Wali Khan University Mardan, Mardan 23200, Pakistan
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Forchheimer 209, 1300 Morris Park Avenue Bronx, NY 10461, USA
| | - Khalaf F Alsharif
- Department of Clinical Laboratory, College of Applied Medical Science, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia
| | - Ashraf Albrakati
- Department of Human Anatomy, College of Medicine, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia
| | - Luciano Saso
- Department of Physiology and Pharmacology "Vittorio Erspamer"Sapienza University, Rome 00185, Italy
| | - Haroon Khan
- Department of Pharmacy, Abdul Wali Khan University Mardan, Mardan 23200, Pakistan.
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6
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Li S, Wang L, Wang Y, Zhang C, Hong Z, Han Z. The synthetic lethality of targeting cell cycle checkpoints and PARPs in cancer treatment. J Hematol Oncol 2022; 15:147. [PMID: 36253861 PMCID: PMC9578258 DOI: 10.1186/s13045-022-01360-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Accepted: 09/30/2022] [Indexed: 11/17/2022] Open
Abstract
Continuous cell division is a hallmark of cancer, and the underlying mechanism is tumor genomics instability. Cell cycle checkpoints are critical for enabling an orderly cell cycle and maintaining genome stability during cell division. Based on their distinct functions in cell cycle control, cell cycle checkpoints are classified into two groups: DNA damage checkpoints and DNA replication stress checkpoints. The DNA damage checkpoints (ATM-CHK2-p53) primarily monitor genetic errors and arrest cell cycle progression to facilitate DNA repair. Unfortunately, genes involved in DNA damage checkpoints are frequently mutated in human malignancies. In contrast, genes associated with DNA replication stress checkpoints (ATR-CHK1-WEE1) are rarely mutated in tumors, and cancer cells are highly dependent on these genes to prevent replication catastrophe and secure genome integrity. At present, poly (ADP-ribose) polymerase inhibitors (PARPi) operate through “synthetic lethality” mechanism with mutant DNA repair pathways genes in cancer cells. However, an increasing number of patients are acquiring PARP inhibitor resistance after prolonged treatment. Recent work suggests that a combination therapy of targeting cell cycle checkpoints and PARPs act synergistically to increase the number of DNA errors, compromise the DNA repair machinery, and disrupt the cell cycle, thereby increasing the death rate of cancer cells with DNA repair deficiency or PARP inhibitor resistance. We highlight a combinational strategy involving PARP inhibitors and inhibition of two major cell cycle checkpoint pathways, ATM-CHK2-TP53 and ATR-CHK1-WEE1. The biological functions, resistance mechanisms against PARP inhibitors, advances in preclinical research, and clinical trials are also reviewed.
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Affiliation(s)
- Shuangying Li
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China
| | - Liangliang Wang
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China
| | - Yuanyuan Wang
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China
| | - Changyi Zhang
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China
| | - Zhenya Hong
- Department of Hematology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China.
| | - Zhiqiang Han
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China.
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7
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Biswas H, Zhao SJ, Makinwa Y, Bassett JS, Musich PR, Liu JY, Zou Y. Prolyl Isomerization-Mediated Conformational Changes Define ATR Subcellular Compartment-Specific Functions. Front Cell Dev Biol 2022; 10:826576. [PMID: 35721505 PMCID: PMC9204103 DOI: 10.3389/fcell.2022.826576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 04/26/2022] [Indexed: 11/13/2022] Open
Abstract
ATR is a PI3K-like kinase protein, regulating checkpoint responses to DNA damage and replication stress. Apart from its checkpoint function in the nucleus, ATR actively engages in an antiapoptotic role at mitochondria following DNA damage. The different functions of ATR in the nucleus and cytoplasm are carried out by two prolyl isomeric forms of ATR: trans- and cis-ATR, respectively. The isomerization occurs at the Pin1 Ser428-Pro429 motif of ATR. Here, we investigated the structural basis of the subcellular location-specific functions of human ATR. Using a mass spectrometry-based footprinting approach, the surface accessibility of ATR lysine residues to sulfo-NHS-LC-biotin modification was monitored and compared between the cis- and the trans-isomers. We have identified two biotin-modified lysine residues, K459 and K469, within the BH3-like domain of cis-ATR that were not accessible in trans-ATR, indicating a conformational change around the BH3 domain between cis- and trans-ATR. The conformational alteration also involved the N-terminal domain and the middle HEAT domain. Moreover, experimental results from an array of complementary assays show that cis-ATR with the accessible BH3 domain was able to bind to tBid while trans-ATR could not. In addition, both cis- and trans-ATR can directly form homodimers via their C-terminal domains without ATRIP, while nuclear (trans-ATR) in the presence of ATRIP forms dimer-dimer complexes involving both N- and C-termini of ATR and ATRIP after UV. Structural characteristics around the Ser428-Pro429 motif and the BH3 domain region are also analyzed by molecular modeling and dynamics simulation. In support, cis conformation was found to be significantly more energetically favorable than trans at the Ser428-Pro429 bond in a 20-aa wild-type ATR peptide. Taken together, our results suggest that the isomerization-induced structural changes of ATR define both its subcellular location and compartment-specific functions and play an essential role in promoting cell survival and DNA damage responses.
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Affiliation(s)
- Himadri Biswas
- Department of Cancer Biology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - Shu-Jun Zhao
- Department of Medicine, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
- Department of Bioengineering, University of Toledo College of Engineering, Toledo, OH, United States
| | - Yetunde Makinwa
- Department of Cancer Biology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - James S. Bassett
- Department of Medicine, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - Phillip R. Musich
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
| | - Jing-Yuan Liu
- Department of Medicine, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
- Department of Bioengineering, University of Toledo College of Engineering, Toledo, OH, United States
| | - Yue Zou
- Department of Cancer Biology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
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8
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Li Z, Wang-Heaton H, Cartwright BM, Makinwa Y, Hilton BA, Musich PR, Shkriabai N, Kvaratskhelia M, Guan S, Chen Q, Yu X, Zou Y. ATR prevents Ca 2+ overload-induced necrotic cell death through phosphorylation-mediated inactivation of PARP1 without DNA damage signaling. FASEB J 2021; 35:e21373. [PMID: 33811702 PMCID: PMC8252533 DOI: 10.1096/fj.202001636rrr] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 12/10/2020] [Accepted: 12/31/2020] [Indexed: 12/19/2022]
Abstract
Hyperactivation of PARP1 is known to be a major cause of necrotic cell death by depleting NAD+/ATP pools during Ca2+ overload which is associated with many ischemic diseases. However, little is known about how PARP1 hyperactivity is regulated during calcium overload. In this study we show that ATR kinase, well known for its role in DNA damage responses, suppresses ionomycin, glutamate, or quinolinic acid‐induced necrotic death of cells including SH‐SY5Y neuronal cells. We found that the inhibition of necrosis requires the kinase activity of ATR. Specifically, ATR binds to and phosphorylates PARP1 at Ser179 after the ionophore treatments. This site‐specific phosphorylation inactivates PARP1, inhibiting ionophore‐induced necrosis. Strikingly, all of this occurs in the absence of detectable DNA damage and signaling up to 8 hours after ionophore treatment. Furthermore, little AIF was released from mitochondria/cytoplasm for nuclear import, supporting the necrotic type of cell death in the early period of the treatments. Our results reveal a novel ATR‐mediated anti‐necrotic mechanism in the cellular stress response to calcium influx without DNA damage signaling.
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Affiliation(s)
- Zhengke Li
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Hui Wang-Heaton
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Brian M Cartwright
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Yetunde Makinwa
- Department of Cancer Biology, University of Toledo College of Medicine, Toledo, OH, USA
| | - Benjamin A Hilton
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Phillip R Musich
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Nikolozi Shkriabai
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO, USA
| | - Mamuka Kvaratskhelia
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO, USA
| | - Shengheng Guan
- Department of Pharmaceutical Chemistry and Mass Spectrometry Facility, University of California, San Francisco, CA, USA
| | - Qian Chen
- Department of Cancer Genetics and Epigenetics, City of Hope, Duarte, CA, USA
| | - Xiaochun Yu
- Department of Cancer Genetics and Epigenetics, City of Hope, Duarte, CA, USA
| | - Yue Zou
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA.,Department of Cancer Biology, University of Toledo College of Medicine, Toledo, OH, USA
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9
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Gorecki L, Andrs M, Korabecny J. Clinical Candidates Targeting the ATR-CHK1-WEE1 Axis in Cancer. Cancers (Basel) 2021; 13:795. [PMID: 33672884 PMCID: PMC7918546 DOI: 10.3390/cancers13040795] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/10/2021] [Accepted: 02/11/2021] [Indexed: 02/07/2023] Open
Abstract
Selective killing of cancer cells while sparing healthy ones is the principle of the perfect cancer treatment and the primary aim of many oncologists, molecular biologists, and medicinal chemists. To achieve this goal, it is crucial to understand the molecular mechanisms that distinguish cancer cells from healthy ones. Accordingly, several clinical candidates that use particular mutations in cell-cycle progressions have been developed to kill cancer cells. As the majority of cancer cells have defects in G1 control, targeting the subsequent intra‑S or G2/M checkpoints has also been extensively pursued. This review focuses on clinical candidates that target the kinases involved in intra‑S and G2/M checkpoints, namely, ATR, CHK1, and WEE1 inhibitors. It provides insight into their current status and future perspectives for anticancer treatment. Overall, even though CHK1 inhibitors are still far from clinical establishment, promising accomplishments with ATR and WEE1 inhibitors in phase II trials present a positive outlook for patient survival.
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Affiliation(s)
- Lukas Gorecki
- Biomedical Research Center, University Hospital Hradec Kralove, Sokolska 581, 500 05 Hradec Kralove, Czech Republic; (L.G.); (M.A.)
| | - Martin Andrs
- Biomedical Research Center, University Hospital Hradec Kralove, Sokolska 581, 500 05 Hradec Kralove, Czech Republic; (L.G.); (M.A.)
- Laboratory of Cancer Cell Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Videnska 1083, 142 00 Prague, Czech Republic
| | - Jan Korabecny
- Biomedical Research Center, University Hospital Hradec Kralove, Sokolska 581, 500 05 Hradec Kralove, Czech Republic; (L.G.); (M.A.)
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10
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Magalhaes YT, Silva GET, Osaki JH, Rocha CRR, Forti FL. RHOAming Through the Nucleotide Excision Repair Pathway as a Mechanism of Cellular Response Against the Effects of UV Radiation. Front Cell Dev Biol 2020; 8:816. [PMID: 33015036 PMCID: PMC7509447 DOI: 10.3389/fcell.2020.00816] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 07/31/2020] [Indexed: 01/19/2023] Open
Abstract
Typical Rho GTPases include the enzymes RhoA, Rac1, and Cdc42 that act as molecular switches to regulate essential cellular processes in eukaryotic cells such as actomyosin dynamics, cell cycle, adhesion, death and differentiation. Recently, it has been shown that different conditions modulate the activity of these enzymes, but their functions still need to be better understood. Here we examine the interplay between RhoA and the NER (Nucleotide Excision Repair) pathway in human cells exposed to UVA, UVB or UVC radiation. The results show high levels and accumulation of UV-induced DNA lesions (strand breaks and cyclobutane pyrimidine dimers, CPDs) in different cells with RhoA loss of function (LoF), either by stable overexpression of negative dominant RhoA (RhoA-N19 mutant), by inhibition with C3 toxin or by transient silencing with siRNA. Cells under RhoA LoF showed reduced levels of γH2AX, p-Chk1 (Ser345) and p-p53 (Ser15) that reflected causally in their accumulation in G1/S phases, in low survival rates and in reduced cell proliferation, also in accordance with the energy of applied UV light. Even NER-deficient cells (XPA, XPC) or DNA translesion synthesis (TLS)-deficient cells (XPV) showed substantial hypersensitivity to UV effects when previously submitted to RhoA LoF. In contrast, analyses of apoptosis, necrosis, autophagy and senescence revealed that all cells displaying normal levels of active RhoA (RhoA-GTP) are more resistant to UV-promoted cell death. This work reaffirms the role of RhoA protein signaling in protecting cells from damage caused by UV radiation and demonstrates relevant communicating mechanisms between actin cytoskeleton and genomic stability.
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Affiliation(s)
- Yuli T Magalhaes
- Biomolecular Systems Signaling Laboratory, Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | - Gisele E T Silva
- Biomolecular Systems Signaling Laboratory, Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | - Juliana H Osaki
- Biomolecular Systems Signaling Laboratory, Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | - Clarissa R R Rocha
- DNA Repair Laboratory, Department of Microbiology, Biomedical Sciences Institute, University of São Paulo, São Paulo, Brazil
| | - Fabio L Forti
- Biomolecular Systems Signaling Laboratory, Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
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11
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Sarkar S, Gaddameedhi S. Solar ultraviolet-induced DNA damage response: Melanocytes story in transformation to environmental melanomagenesis. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2020; 61:736-751. [PMID: 32281145 PMCID: PMC9675355 DOI: 10.1002/em.22370] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 03/13/2020] [Accepted: 03/27/2020] [Indexed: 05/14/2023]
Abstract
Exposure to sunlight is both beneficial, as it heats the planet to a comfortable temperature, and potentially harmful, since sunlight contains ultraviolet radiation (UVR), which is deemed detrimental for living organisms. Earth's ozone layer plays a vital role in blocking most of the extremely dangerous UVC; however, low frequency/energy UVR (i.e., UVB and UVA) seeps through in minute amount and reaches the Earth's surface. Both UVB and UVA are physiologically responsible for a plethora of skin ailments, including skin cancers. The UVR is readily absorbed by the genomic DNA of skin cells, causing DNA bond distortion and UV-induced DNA damage. As a defense mechanism, the DNA damage response (DDR) signaling in skin cells activates nucleotide excision repair (NER), which is responsible for the removal of UVR-induced DNA photolesions and helps maintain the genomic integrity of the cells. Failure of proper NER function leads to mutagenesis and development of skin cancers. One of the deadliest form of skin cancers is melanoma which originates upon the genetic transformation of melanocytes, melanin producing skin cells. NER is a well-studied DNA repair system in the whole skin, as a tissue, but not much is known about it in melanocytes. Therefore, this review encapsulates NER in melanocytes, with a specific focus on its functional regulators and their cross talks due to skin heterogeneity and divulging the potential knowledge gap in the field.
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Affiliation(s)
- Soumyadeep Sarkar
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA
| | - Shobhan Gaddameedhi
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA
- Sleep and Performance Research Center, Washington State University, Spokane, WA
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12
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XPA: DNA Repair Protein of Significant Clinical Importance. Int J Mol Sci 2020; 21:ijms21062182. [PMID: 32235701 PMCID: PMC7139726 DOI: 10.3390/ijms21062182] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 03/18/2020] [Accepted: 03/18/2020] [Indexed: 02/08/2023] Open
Abstract
The nucleotide excision repair (NER) pathway is activated in response to a broad spectrum of DNA lesions, including bulky lesions induced by platinum-based chemotherapeutic agents. Expression levels of NER factors and resistance to chemotherapy has been examined with some suggestion that NER plays a role in tumour resistance; however, there is a great degree of variability in these studies. Nevertheless, recent clinical studies have suggested Xeroderma Pigmentosum group A (XPA) protein, a key regulator of the NER pathway that is essential for the repair of DNA damage induced by platinum-based chemotherapeutics, as a potential prognostic and predictive biomarker for response to treatment. XPA functions in damage verification step in NER, as well as a molecular scaffold to assemble other NER core factors around the DNA damage site, mediated by protein–protein interactions. In this review, we focus on the interacting partners and mechanisms of regulation of the XPA protein. We summarize clinical oncology data related to this DNA repair factor, particularly its relationship with treatment outcome, and examine the potential of XPA as a target for small molecule inhibitors.
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13
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Targeting ATR as Cancer Therapy: A new era for synthetic lethality and synergistic combinations? Pharmacol Ther 2020; 207:107450. [DOI: 10.1016/j.pharmthera.2019.107450] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 11/22/2019] [Indexed: 12/22/2022]
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14
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Polynuclear ruthenium organometallic compounds induce DNA damage in human cells identified by the nucleotide excision repair factor XPC. Biosci Rep 2019; 39:BSR20190378. [PMID: 31227614 PMCID: PMC6629949 DOI: 10.1042/bsr20190378] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 06/14/2019] [Accepted: 06/19/2019] [Indexed: 12/13/2022] Open
Abstract
Ruthenium organometallic compounds represent an attractive avenue in developing alternatives to platinum-based chemotherapeutic agents. While evidence has been presented indicating ruthenium-based compounds interact with isolated DNA in vitro, it is unclear what effect these compounds exert in cells. Moreover, the antibiotic efficacy of polynuclear ruthenium organometallic compounds remains uncertain. In the present study, we report that exposure to polynuclear ruthenium organometallic compounds induces recruitment of damaged DNA sensing protein Xeroderma pigmentosum Group C into chromatin-immobilized foci. Additionally, we observed one of the tested polynuclear ruthenium organometallic compounds displayed increased cytotoxicity against human cells deficient in nucleotide excision repair (NER). Taken together, these results suggest that polynuclear ruthenium organometallic compounds induce DNA damage in cells, and that cellular resistance to these compounds may be influenced by the NER DNA repair phenotype of the cells.
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15
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Jarrett SG, Carter KM, Bautista RM, He D, Wang C, D'Orazio JA. Sirtuin 1-mediated deacetylation of XPA DNA repair protein enhances its interaction with ATR protein and promotes cAMP-induced DNA repair of UV damage. J Biol Chem 2018; 293:19025-19037. [PMID: 30327428 DOI: 10.1074/jbc.ra118.003940] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 10/12/2018] [Indexed: 12/31/2022] Open
Abstract
Blunted melanocortin 1 receptor (MC1R) signaling promotes melanocyte genomic instability in part by attenuating cAMP-mediated DNA repair responses, particularly nucleotide excision repair (NER), which recognizes and clears mutagenic photodamage. cAMP-enhanced NER is mediated by interactions between the ataxia telangiectasia-mutated and Rad3-related (ATR) and xeroderma pigmentosum complementation group A (XPA) proteins. We now report a critical role for sirtuin 1 (SIRT1) in regulating ATR-mediated phosphorylation of XPA. SIRT1 deacetylates XPA at residues Lys-63, Lys-67, and Lys-215 to promote interactions with ATR. Mutant XPA containing acetylation mimetics at residues Lys-63, Lys-67, and Lys-215 exhibit blunted UV-dependent ATR-XPA interactions even in the presence of cAMP signals. ATR-mediated phosphorylation of XPA on Ser-196 enhances cAMP-mediated optimization of NER and is promoted by SIRT1-mediated deacetylation of XPA on Lys-63, Lys-67, and Lys-215. Interference with ATR-mediated XPA phosphorylation at Ser-196 by persistent acetylation of XPA at Lys-63, Lys-67, and Lys-215 delays repair of UV-induced DNA damage and attenuates cAMP-enhanced NER. Our study identifies a regulatory ATR-SIRT1-XPA axis in cAMP-mediated regulation melanocyte genomic stability, involving SIRT1-mediated deacetylation (Lys-63, Lys-67, and Lys-215) and ATR-dependent phosphorylation (Ser-196) post-translational modifications of the core NER factor XPA.
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Affiliation(s)
- Stuart G Jarrett
- From the Markey Cancer Center and .,the Departments of Toxicology and Cancer Biology
| | | | | | - Daheng He
- From the Markey Cancer Center and.,Biostatistics and Bioinformatics, and
| | - Chi Wang
- From the Markey Cancer Center and.,Biostatistics and Bioinformatics, and
| | - John A D'Orazio
- From the Markey Cancer Center and .,the Departments of Toxicology and Cancer Biology.,Pediatrics, University of Kentucky College of Medicine, Lexington, Kentucky 40536
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16
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Targeting DNA repair with aphidicolin sensitizes primary chronic lymphocytic leukemia cells to purine analogs. Oncotarget 2018; 7:38367-38379. [PMID: 27223263 PMCID: PMC5122396 DOI: 10.18632/oncotarget.9525] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 05/04/2016] [Indexed: 11/25/2022] Open
Abstract
Purine analogs are among the most effective chemotherapeutic drugs for the treatment of chronic lymphocytic leukemia (CLL). However, chemoresistance and toxicity limit their clinical use. Here, we report that the DNA polymerase inhibitor aphidicolin, which displayed negligible cytotoxicity as a single agent in primary CLL cells, markedly synergizes with fludarabine and cladribine via enhanced apoptosis. Importantly, synergy was recorded regardless of CLL prognostic markers. At the molecular level, aphidicolin enhanced purine analog-induced phosphorylation of p53 and accumulation of γH2AX, consistent with increase in DNA damage. In addition, aphidicolin delayed γH2AX disappearance that arises after removal of purine analogs, suggesting that aphidicolin causes an increase in DNA damage by impeding DNA damage repair. Similarly, aphidicolin inhibited UV-induced DNA repair known to occur primarily through the nucleotide excision repair (NER) pathway. Finally, we showed that fludarabine induced nuclear import of XPA, an indispensable factor for NER, and that XPA silencing sensitized cell lines to undergo apoptosis in response to fludarabine. Together, our data indicate that aphidicolin potentiates the cytotoxicity of purine analogs by inhibiting a DNA repair pathway that involves DNA polymerases, most likely NER, and provide a rationale for manipulating it to therapeutic advantage.
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17
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Musich PR, Li Z, Shell SM, Zou Y. Reprint of: XPA is primarily cytoplasmic but is transported into the nucleus upon UV damage in a cell cycle dependent manner. DNA Repair (Amst) 2018; 62:28-29. [PMID: 29402654 DOI: 10.1016/j.dnarep.2018.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 10/11/2017] [Indexed: 10/18/2022]
Affiliation(s)
- Phillip R Musich
- Department of Biomedical Sciences, J.H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614-1708, USA.
| | - Zhengke Li
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope, 1500 East Duarte Road, Duarte, CA 91010-3000, USA
| | - Steven M Shell
- Department of Natural Sciences, The University of Virginia's College at Wise, 1 College Avenue, Wise, VA 24293, USA
| | - Yue Zou
- Department of Biomedical Sciences, J.H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614-1708, USA
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18
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XPA is primarily cytoplasmic but is transported into the nucleus upon UV damage in a cell cycle dependent manner. DNA Repair (Amst) 2017; 60:50-51. [DOI: 10.1016/j.dnarep.2017.10.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 10/11/2017] [Indexed: 12/24/2022]
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19
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Echinacoside Alleviates UVB Irradiation-Mediated Skin Damage via Inhibition of Oxidative Stress, DNA Damage, and Apoptosis. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:6851464. [PMID: 29213352 PMCID: PMC5682084 DOI: 10.1155/2017/6851464] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 08/30/2017] [Indexed: 12/20/2022]
Abstract
Ultraviolet B (UVB) irradiation has been known to cause skin damage, which is associated with oxidative stress, DNA damage, and apoptosis. Echinacoside is a phenylethanoid glycoside isolated from Herba Cistanches, which exhibits strong antioxidant activity. In this study, we evaluate the photoprotective effect of echinacoside on UVB-induced skin damage and explore the potential molecular mechanism. BALB/c mice and HaCaT cells were treated with echinacoside before UVB exposure. Histopathological examination was used to evaluate the skin damage. Cell viability, lactate dehydrogenase (LDH) levels, antioxidant enzyme activities, reactive oxygen species (ROS) generation, DNA damage, and apoptosis were measured as well. Western blot was used to measure the expression of related proteins. The results revealed that pretreatment of echinacoside ameliorated the skin injury; attenuated oxidative stress, DNA damage, and apoptosis caused by UVB exposure; and normalized the protein levels of ATR, p53, PIAS3, hnRNP K, PARP, and XPA. To summarize, echinacoside is beneficial in the prevention of UVB-induced DNA damage and apoptosis of the skin in vivo and in vitro.
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20
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The melanocortin signaling cAMP axis accelerates repair and reduces mutagenesis of platinum-induced DNA damage. Sci Rep 2017; 7:11708. [PMID: 28916831 PMCID: PMC5601928 DOI: 10.1038/s41598-017-12056-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 09/01/2017] [Indexed: 12/22/2022] Open
Abstract
Using primary melanocytes and HEK293 cells, we found that cAMP signaling accelerates repair of bi- and mono-functional platinum-induced DNA damage. Elevating cAMP signaling either by the agonistic MC1R ligand melanocyte stimulating hormone (MSH) or by pharmacologic cAMP induction by forskolin enhanced clearance of intrastrand cisplatin-adducts in melanocytes or MC1R-transfected HEK293 cells. MC1R antagonists human beta-defensin 3 and agouti signaling protein blocked MSH- but not forskolin-mediated enhancement of platinum-induced DNA damage. cAMP-enhanced repair of cisplatin-induced DNA damage was dependent on PKA-mediated phosphorylation of ATR on S435 which promoted ATR’s interaction with the key NER factor xeroderma pigmentosum A (XPA) and facilitated recruitment of an XPA-ATR-pS435 complex to sites of cisplatin DNA damage. Moreover, we developed an oligonucleotide retrieval immunoprecipitation (ORiP) assay using a novel platinated-DNA substrate to establish kinetics of ATR-pS435 and XPA’s associations with cisplatin-damaged DNA. Expression of a non-phosphorylatable ATR-S435A construct or deletion of A kinase-anchoring protein 12 (AKAP12) impeded platinum adduct clearance and prevented cAMP-mediated enhancement of ATR and XPA’s associations with cisplatin-damaged DNA, indicating that ATR phosphorylation at S435 is necessary for cAMP-enhanced repair of platinum-induced damage and protection against cisplatin-induced mutagenesis. These data implicate cAMP signaling as a critical regulator of genomic stability against platinum-induced mutagenesis.
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21
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Manandhar M, Lowery MG, Boulware KS, Lin KH, Lu Y, Wood RD. Transcriptional consequences of XPA disruption in human cell lines. DNA Repair (Amst) 2017; 57:76-90. [PMID: 28704716 PMCID: PMC5731452 DOI: 10.1016/j.dnarep.2017.06.028] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 06/26/2017] [Accepted: 06/27/2017] [Indexed: 11/25/2022]
Abstract
Nucleotide excision repair (NER) in mammalian cells requires the xeroderma pigmentosum group A protein (XPA) as a core factor. Remarkably, XPA and other NER proteins have been detected by chromatin immunoprecipitation at some active promoters, and NER deficiency is reported to influence the activated transcription of selected genes. However, the global influence of XPA on transcription in human cells has not been determined. We analyzed the human transcriptome by RNA sequencing (RNA-Seq). We first confirmed that XPA is confined to the cell nucleus even in the absence of external DNA damage, in contrast to previous reports that XPA is normally resident in the cytoplasm and is imported following DNA damage. We then analyzed four genetically matched human cell line pairs deficient or proficient in XPA. Of the ∼14,000 genes transcribed in each cell line, 325 genes (2%) had a significant XPA-dependent directional change in gene expression that was common to all four pairs (with a false discovery rate of 0.05). These genes were enriched in pathways for the maintenance of mitochondria. Only 27 common genes were different by more than 1.5-fold. The most significant hits were AKR1C1 and AKR1C2, involved in steroid hormone metabolism. AKR1C2 protein was lower in all of the immortalized XPA-deficient cells. Retinoic acid treatment led to modest XPA-dependent activation of some genes with transcription-related functions. We conclude that XPA status does not globally influence human gene transcription. However, XPA significantly influences expression of a small subset of genes important for mitochondrial functions and steroid hormone metabolism. The results may help explain defects in neurological function and sterility in individuals with xeroderma pigmentosum.
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Affiliation(s)
- Mandira Manandhar
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, P.O. Box 389, Smithville, TX, 78957, USA; MD Anderson Cancer Center UT Health Graduate School of Biomedical Sciences, TX, USA
| | - Megan G Lowery
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, P.O. Box 389, Smithville, TX, 78957, USA
| | - Karen S Boulware
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, P.O. Box 389, Smithville, TX, 78957, USA
| | - Kevin H Lin
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, P.O. Box 389, Smithville, TX, 78957, USA
| | - Yue Lu
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, P.O. Box 389, Smithville, TX, 78957, USA
| | - Richard D Wood
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, P.O. Box 389, Smithville, TX, 78957, USA; MD Anderson Cancer Center UT Health Graduate School of Biomedical Sciences, TX, USA.
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22
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Hilton BA, Liu J, Cartwright BM, Liu Y, Breitman M, Wang Y, Jones R, Tang H, Rusinol A, Musich PR, Zou Y. Progerin sequestration of PCNA promotes replication fork collapse and mislocalization of XPA in laminopathy-related progeroid syndromes. FASEB J 2017; 31:3882-3893. [PMID: 28515154 DOI: 10.1096/fj.201700014r] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2017] [Accepted: 04/24/2017] [Indexed: 02/06/2023]
Abstract
Hutchinson-Gilford progeria syndrome (HGPS) is a rare genetic disorder that is caused by a point mutation in the LMNA gene, resulting in production of a truncated farnesylated-prelamin A protein (progerin). We previously reported that XPA mislocalized to the progerin-induced DNA double-strand break (DSB) sites, blocking DSB repair, which led to DSB accumulation, DNA damage responses, and early replication arrest in HGPS. In this study, the XPA mislocalization to DSBs occurred at stalled or collapsed replication forks, concurrent with a significant loss of PCNA at the forks, whereas PCNA efficiently bound to progerin. This PCNA sequestration likely exposed ds-ssDNA junctions at replication forks for XPA binding. Depletion of XPA or progerin each significantly restored PCNA at replication forks. Our results suggest that although PCNA is much more competitive than XPA in binding replication forks, PCNA sequestration by progerin may shift the equilibrium to favor XPA binding. Furthermore, we demonstrated that progerin-induced apoptosis could be rescued by XPA, suggesting that XPA-replication fork binding may prevent apoptosis in HGPS cells. Our results propose a mechanism for progerin-induced genome instability and accelerated replicative senescence in HGPS.-Hilton, B. A., Liu, J., Cartwright, B. M., Liu, Y., Breitman, M., Wang, Y., Jones, R., Tang, H., Rusinol, A., Musich, P. R., Zou, Y. Progerin sequestration of PCNA promotes replication fork collapse and mislocalization of XPA in laminopathy-related progeroid syndromes.
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Affiliation(s)
- Benjamin A Hilton
- Department of Biomedical Sciences, J. H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA
| | - Ji Liu
- Department of Biochemistry and Molecular Biology, West China Center of Medical Sciences, Sichuan University, Chengdu, China
| | - Brian M Cartwright
- Department of Biomedical Sciences, J. H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA
| | - Yiyong Liu
- Department of Biomedical Sciences, J. H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA
| | - Maya Breitman
- Department of Biomedical Sciences, J. H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA
| | - Youjie Wang
- Ministry of Education (MOE) Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Rowdy Jones
- Department of Biomedical Sciences, J. H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA
| | - Hui Tang
- Department of Biomedical Sciences, J. H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA
| | - Antonio Rusinol
- Department of Biomedical Sciences, J. H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA
| | - Phillip R Musich
- Department of Biomedical Sciences, J. H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA
| | - Yue Zou
- Department of Biomedical Sciences, J. H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA;
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23
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Targeting the ATR-CHK1 Axis in Cancer Therapy. Cancers (Basel) 2017; 9:cancers9050041. [PMID: 28448462 PMCID: PMC5447951 DOI: 10.3390/cancers9050041] [Citation(s) in RCA: 141] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 04/23/2017] [Accepted: 04/25/2017] [Indexed: 12/14/2022] Open
Abstract
Targeting the DNA damage response (DDR) is a new therapeutic approach in cancer that shows great promise for tumour selectivity. Key components of the DDR are the ataxia telangiectasia mutated and Rad3 related (ATR) and checkpoint kinase 1 (CHK1) kinases. This review article describes the role of ATR and its major downstream target, CHK1, in the DDR and why cancer cells are particularly reliant on the ATR-CHK1 pathway, providing the rationale for targeting these kinases, and validation of this hypothesis by genetic manipulation. The recent development of specific inhibitors and preclinical data using these inhibitors not only as chemosensitisers and radiosensitisers but also as single agents to exploit specific pathologies of tumour cells is described. These potent and specific inhibitors have now entered clinical trial and early results are presented.
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24
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Dietary proanthocyanidins prevent ultraviolet radiation-induced non-melanoma skin cancer through enhanced repair of damaged DNA-dependent activation of immune sensitivity. Semin Cancer Biol 2017; 46:138-145. [PMID: 28412456 DOI: 10.1016/j.semcancer.2017.04.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 03/22/2017] [Accepted: 04/10/2017] [Indexed: 12/31/2022]
Abstract
Numerous plant products have been used to prevent and manage a wide variety of diseases for centuries. These products are now considered as promising options for the development of more effective and less toxic alternatives to the systems of medicine developed primarily in developed countries in the modern era. Grape seed proanthocyanidins (GSPs) are of great interest due to their anti-carcinogenic effects that have been demonstrated using various tumor models including ultraviolet (UV) radiation-induced non-melanoma skin cancer. In a pre-clinical mouse model supplementation of a control diet (AIN76A) with GSPs at concentrations of 0.2% and 0.5% (w/w) significantly inhibits the growth and multiplicity of UVB radiation-induced skin tumors. In this review, we summarize the evidence that this inhibition of UVB-induced skin tumor development by dietary GSPs is mediated by a multiplicity of coordinated effects including: (i) Promotion of the repair of damaged DNA by nuclear excision repair mechanisms, and (ii) DNA repair-dependent stimulation of the immune system following the functional activation of dendritic cells and effector T cells. Dietary GSPs hold promise for the development of an effective alternative strategy for the prevention of excessive solar UVB radiation exposure-induced skin diseases including the risk of non-melanoma skin cancer in humans.
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25
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Lee JM, Park JM, Kang TH. Enhancement of UV-induced nucleotide excision repair activity upon forskolin treatment is cell growth-dependent. BMB Rep 2017; 49:566-571. [PMID: 27470212 PMCID: PMC5227299 DOI: 10.5483/bmbrep.2016.49.10.097] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Indexed: 11/20/2022] Open
Abstract
Forskolin (FSK), an adenylyl cyclase activator, has recently been shown to enhance nucleotide excision repair (NER) upon UV exposure. However, our study revealed that this effect was detected in human skin epithelial ARPE19 cells only in growing cells, but not in non-cycling cells. When the cells were grown at low density (70% confluence), FSK was capable of stimulating cAMP responsive element binding (CREB) phosphorylation, a marker for FSK-stimulated PKA activation, and resulted in a significant increase of NER activity compared to control treatment. However, cells grown under 100% confluent conditions showed neither FSK-induced CREB phosphorylation nor the resulting NER enhancement. These findings indicate that cellular growth is critical for FSK-induced NER enhancement and suggest that cellular growth conditions should be considered as a variable while evaluating a reagent’s pharmacotherapeutic efficacy. [BMB Reports 2016; 49(10): 566-571]
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Affiliation(s)
- Jeong-Min Lee
- Department of Biological Science, Dong-A University, Busan 49315, Korea
| | - Jeong-Min Park
- Department of Biological Science, Dong-A University, Busan 49315, Korea
| | - Tae-Hong Kang
- Department of Biological Science, Dong-A University, Busan 49315, Korea
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26
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Musich PR, Li Z, Zou Y. Xeroderma Pigmentosa Group A (XPA), Nucleotide Excision Repair and Regulation by ATR in Response to Ultraviolet Irradiation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 996:41-54. [PMID: 29124689 DOI: 10.1007/978-3-319-56017-5_4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The sensitivity of Xeroderma pigmentosa (XP) patients to sunlight has spurred the discovery and genetic and biochemical analysis of the eight XP gene products (XPA-XPG plus XPV) responsible for this disorder. These studies also have served to elucidate the nucleotide excision repair (NER) process, especially the critical role played by the XPA protein. More recent studies have shown that NER also involves numerous other proteins normally employed in DNA metabolism and cell cycle regulation. Central among these is ataxia telangiectasia and Rad3-related (ATR), a protein kinase involved in intracellular signaling in response to DNA damage, especially DNA damage-induced replicative stresses. This review summarizes recent findings on the interplay between ATR as a DNA damage signaling kinase and as a novel ligand for intrinsic cell death proteins to delay damage-induced apoptosis, and on ATR's regulation of XPA and the NER process for repair of UV-induced DNA adducts. ATR's regulatory role in the cytosolic-to-nuclear translocation of XPA will be discussed. In addition, recent findings elucidating a non-NER role for XPA in DNA metabolism and genome stabilization at ds-ssDNA junctions, as exemplified in prematurely aging progeroid cells, also will be reviewed.
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Affiliation(s)
- Phillip R Musich
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, 37614, USA
| | - Zhengke Li
- Department of Cancer Genetics and Epigenetics, City of Hope Comprehensive Cancer Center, 1500 E Duarte Rd, Duarte, CA, 91007, USA
| | - Yue Zou
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, 37614, USA.
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27
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Sugitani N, Sivley RM, Perry KE, Capra JA, Chazin WJ. XPA: A key scaffold for human nucleotide excision repair. DNA Repair (Amst) 2016; 44:123-135. [PMID: 27247238 DOI: 10.1016/j.dnarep.2016.05.018] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Nucleotide excision repair (NER) is essential for removing many types of DNA lesions from the genome, yet the mechanisms of NER in humans remain poorly understood. This review summarizes our current understanding of the structure, biochemistry, interaction partners, mechanisms, and disease-associated mutations of one of the critical NER proteins, XPA.
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Affiliation(s)
- Norie Sugitani
- Departments of Biochemistry, Biological Sciences, Biomedical Informatics, Chemistry, and Computer Science, and Vanderbilt Genetics Institute and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232-7917, United States
| | - Robert M Sivley
- Departments of Biochemistry, Biological Sciences, Biomedical Informatics, Chemistry, and Computer Science, and Vanderbilt Genetics Institute and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232-7917, United States
| | - Kelly E Perry
- Departments of Biochemistry, Biological Sciences, Biomedical Informatics, Chemistry, and Computer Science, and Vanderbilt Genetics Institute and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232-7917, United States
| | - John A Capra
- Departments of Biochemistry, Biological Sciences, Biomedical Informatics, Chemistry, and Computer Science, and Vanderbilt Genetics Institute and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232-7917, United States
| | - Walter J Chazin
- Departments of Biochemistry, Biological Sciences, Biomedical Informatics, Chemistry, and Computer Science, and Vanderbilt Genetics Institute and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232-7917, United States.
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28
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Guthrie OW. Localization and distribution of neurons that co-express xeroderma pigmentosum-A and epidermal growth factor receptor within Rosenthal's canal. Acta Histochem 2015; 117:688-95. [PMID: 26493720 DOI: 10.1016/j.acthis.2015.10.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 10/06/2015] [Accepted: 10/10/2015] [Indexed: 12/12/2022]
Abstract
Xeroderma pigmentosum-A (XPA) is a C4-type zinc-finger scaffolding protein that regulates the removal of bulky-helix distorting DNA damage products from the genome. Phosphorylation of serine residues within the XPA protein is associated with improved protection of genomic DNA and cell death resistance. Therefore, kinase signaling is one important mechanism for regulating the protective function of XPA. Previous experiments have shown that spiral ganglion neurons (SGNs) may mobilize XPA as a general stress response to chemical and physical ototoxicants. Therapeutic optimization of XPA via kinase signaling could serve as a means to improve DNA repair capacity within neurons following injury. The kinase signaling activity of the epidermal growth factor receptor (EGFR) has been shown in tumor cell lines to increase the repair of DNA damage products that are primarily repaired by XPA. Such observations suggest that EGFR may regulate the protective function of XPA. However, it is not known whether SGNs in particular or neurons in general could co-express XPA and EGFR. In the current study gene and protein expression of XPA and EGFR were determined from cochlear homogenates. Immunofluorescence assays were then employed to localize neurons expressing both EGFR and XPA within the ganglion. This work was then confirmed with double-immunohistochemistry. Rosenthal's canal served as the reference space in these experiments and design-based stereology was employed in first-order stereology quantification of immunoreactive neurons. The results confirmed that a population of SGNs that constitutively express XPA may also express the EGFR. These results provide the basis for future experiments designed to therapeutically manipulate the EGFR in order to regulate XPA activity and restore gene function in neurons following DNA damage.
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Karnitz LM, Zou L. Molecular Pathways: Targeting ATR in Cancer Therapy. Clin Cancer Res 2015; 21:4780-5. [PMID: 26362996 DOI: 10.1158/1078-0432.ccr-15-0479] [Citation(s) in RCA: 181] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 08/12/2015] [Indexed: 12/19/2022]
Abstract
The human ATR gene encodes a kinase that is activated by DNA damage and replication stress as a central transducer of a checkpoint signaling pathway. Once activated, ATR phosphorylates multiple substrates, including the kinase Chk1, to regulate cell-cycle progression, replication fork stability, and DNA repair. These events promote cell survival during replication stress and in cells with DNA damage. Accordingly, there has been the tantalizing possibility that ATR inhibitors would be therapeutically useful, especially if they were more effective in tumor versus normal cells. Indeed, multiple studies have demonstrated that alterations that promote tumorigenesis, such as defects in the ATM-p53 pathway, constitutive oncogene activation, and acquisition of the alternative lengthening of telomeres pathway, render tumor cells sensitive to ATR inhibitor monotherapy and/or increase the synergy between ATR inhibitors and genotoxic chemotherapies. Now, nearly two decades after the discovery of ATR, two highly selective and potent ATR inhibitors, AZD6738 and VX-970, are in early-phase clinical trials either as monotherapies or paired with a variety of genotoxic chemotherapies. These trials will generate important insights into the effects of ATR inhibition in humans and the potential role of inhibiting this kinase in the treatment of human malignancies.
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Affiliation(s)
- Larry M Karnitz
- Division of Oncology Research and Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota.
| | - Lee Zou
- Massachusetts General Hospital Cancer Center, Department of Pathology, Harvard Medical School, Boston, Massachusetts
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Spryszyńska S, Smok-Pieniążek A, Ferlińska M, Roszak J, Nocuń M, Stępnik M. The influence of ATM, ATR, DNA-PK inhibitors on the cytotoxic and genotoxic effects of dibenzo[def,p]chrysene on human hepatocellular cancer cell line HepG2. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2015; 791:12-24. [PMID: 26338538 DOI: 10.1016/j.mrgentox.2015.07.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 07/09/2015] [Accepted: 07/21/2015] [Indexed: 02/06/2023]
Abstract
The effect of inhibitors of phosphatidylinositol-3-kinase related kinases (PIKK): ataxia-telangiectasia mutated (ATM), ATM- and Rad3-related (ATR) and DNA-dependent protein kinase (DNA-PK) on the response of HepG2 human liver cancer cells to dibenzo[def,p]chrysene (DBC) was investigated. High cytotoxicity of DBC (IC50=0.1μM) was observed after 72h incubation. PIKK inhibitors: KU55933 (5μM), NU7026 (10μM) or caffeine (1 and 2mM) when used alone did not significantly influence the cytotoxicity. However, two combinations: KU55933/NU7026 and caffeine/NU7026 significantly increased HepG2 viability (by 25%) after treatment with DBC at 0.5μM. The cytoprotective effect was confirmed by cell cycle and apoptosis/necrosis analysis. DNA damage level after exposure to DBC assessed by comet assay (single strand breaks) showed a long persistence and significant decrease after incubation of the cells in the presence the inhibitors (the combination of KU55933+NU7026 showed the strongest effect). Weak induction of reactive oxygen species (ROS) by DBC (0.5μM) was observed. Although, KU55933 and NU7026 when used alone did not increase ROS levels in the cells, their combination induced the ROS increase and moderately enhanced ROS generation by DBC. We propose a mechanism how cells with damaged DNA after exposure to DBC and under the condition of PIKK inhibition, may be at higher risk of undergoing malignant transformation.
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Affiliation(s)
- Sylwia Spryszyńska
- Department of Toxicology and Carcinogenesis, Nofer Institute of Occupational Medicine, Łódź, Poland.
| | - Anna Smok-Pieniążek
- Department of Toxicology and Carcinogenesis, Nofer Institute of Occupational Medicine, Łódź, Poland.
| | - Magdalena Ferlińska
- Department of Toxicology and Carcinogenesis, Nofer Institute of Occupational Medicine, Łódź, Poland.
| | - Joanna Roszak
- Department of Toxicology and Carcinogenesis, Nofer Institute of Occupational Medicine, Łódź, Poland.
| | - Marek Nocuń
- Department of Toxicology and Carcinogenesis, Nofer Institute of Occupational Medicine, Łódź, Poland.
| | - Maciej Stępnik
- Department of Toxicology and Carcinogenesis, Nofer Institute of Occupational Medicine, Łódź, Poland.
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Alekseev S, Coin F. Orchestral maneuvers at the damaged sites in nucleotide excision repair. Cell Mol Life Sci 2015; 72:2177-86. [PMID: 25681868 PMCID: PMC11113351 DOI: 10.1007/s00018-015-1859-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 01/30/2015] [Accepted: 02/11/2015] [Indexed: 11/25/2022]
Abstract
To safeguard the genome from the accumulation of deleterious effects arising from DNA lesions, cells developed several DNA repair mechanisms that remove specific types of damage from the genome. Among them, Nucleotide Excision Repair (NER) is unique in its ability to remove a very broad spectrum of lesions, the most important of which include UV-induced damage, bulky chemical adducts and some forms of oxidative damage. Two sub-pathways exist in NER; Transcription-Coupled Repair (TC-NER) removes lesion localized exclusively in transcribed genes while Global Genome Repair (GG-NER) removes lesions elsewhere. In TC- or GG-NER, more than 30 proteins detect, open, incise and resynthesize DNA. Intriguingly, half of them are involved in the detection of DNA damage, implying that this is a crucial repair step requiring a high level of regulation. We review here the complex damage recognition step of GG-NER with a focus on post-translational modifications that help the comings and goings of several protein complexes on the same short damaged DNA locus.
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Affiliation(s)
- Sergey Alekseev
- Department of Functional Genomics and Cancer, IGBMC, Equipe Labellisée Ligue 2014, CNRS/INSERM/University of Strasbourg, BP 163, 67404 Illkirch Cedex, C. U. Strasbourg, France
| | - Frédéric Coin
- Department of Functional Genomics and Cancer, IGBMC, Equipe Labellisée Ligue 2014, CNRS/INSERM/University of Strasbourg, BP 163, 67404 Illkirch Cedex, C. U. Strasbourg, France
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Yan S, Sorrell M, Berman Z. Functional interplay between ATM/ATR-mediated DNA damage response and DNA repair pathways in oxidative stress. Cell Mol Life Sci 2014; 71:3951-67. [PMID: 24947324 DOI: 10.1007/s00018-014-1666-4] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 06/03/2014] [Accepted: 06/05/2014] [Indexed: 02/07/2023]
Abstract
To maintain genome stability, cells have evolved various DNA repair pathways to deal with oxidative DNA damage. DNA damage response (DDR) pathways, including ATM-Chk2 and ATR-Chk1 checkpoints, are also activated in oxidative stress to coordinate DNA repair, cell cycle progression, transcription, apoptosis, and senescence. Several studies demonstrate that DDR pathways can regulate DNA repair pathways. On the other hand, accumulating evidence suggests that DNA repair pathways may modulate DDR pathway activation as well. In this review, we summarize our current understanding of how various DNA repair and DDR pathways are activated in response to oxidative DNA damage primarily from studies in eukaryotes. In particular, we analyze the functional interplay between DNA repair and DDR pathways in oxidative stress. A better understanding of cellular response to oxidative stress may provide novel avenues of treating human diseases, such as cancer and neurodegenerative disorders.
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Affiliation(s)
- Shan Yan
- Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC, 28223, USA,
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Jarrett SG, Horrell EMW, Christian PA, Vanover JC, Boulanger MC, Zou Y, D'Orazio JA. RETRACTED: PKA-mediated phosphorylation of ATR promotes recruitment of XPA to UV-induced DNA damage. Mol Cell 2014; 54:999-1011. [PMID: 24950377 PMCID: PMC4076709 DOI: 10.1016/j.molcel.2014.05.030] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 03/28/2014] [Accepted: 05/17/2014] [Indexed: 12/21/2022]
Abstract
This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the authors. An investigation by the University of Kentucky (UK) recently determined that it contains fabricated and/or falsified data committed by the lead author on the paper. The results of the investigation can be viewed at https://ori.hhs.gov/content/case-summary-jarrett-stuart-g. UK identified that there were duplications and flips of panels in three figures (Figures 7D, 7E, and S3C), and original data could not be retrieved. In Figures 7D and 7E, there are inappropriate loading controls: reuse and relabeling between Figure 7D (no UV) and Figure 7E (+ UV). In Figure S3C, the loading controls for 6-4 PP (second row down) are the same as those for XPA (fourth row down), but are flipped. In both cases, the authors could not recover the original data, since primary data were stored only on a computer associated with a Storm PhosphorImager and were lost when that computer crashed. Thus, this is considered data fabrication, and the authors are retracting the paper. The authors apologize to the scientific community for any inconveniences or challenges resulting from the publication and retraction of this manuscript. Authors Stuart Jarrett and Jillian Vanover could not be reached. The remaining authors agree to the retraction.
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Affiliation(s)
- Stuart G Jarrett
- Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY 40536, USA
| | - Erin M Wolf Horrell
- Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY 40536, USA; Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, USA
| | - Perry A Christian
- Graduate Center for Toxicology, University of Kentucky College of Medicine, Lexington, KY 40536, USA
| | - Jillian C Vanover
- Department of Pharmacology and Nutrition Sciences, University of Kentucky College of Medicine, Lexington, KY 40536, USA
| | - Mary C Boulanger
- Department of Dietetics and Human Nutrition, University of Kentucky College of Medicine, Lexington, KY 40536, USA
| | - Yue Zou
- Department of Biochemistry and Molecular Biology, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, USA
| | - John A D'Orazio
- Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY 40536, USA; Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, USA; Graduate Center for Toxicology, University of Kentucky College of Medicine, Lexington, KY 40536, USA; Department of Pharmacology and Nutrition Sciences, University of Kentucky College of Medicine, Lexington, KY 40536, USA; Department of Dietetics and Human Nutrition, University of Kentucky College of Medicine, Lexington, KY 40536, USA; Department of Pediatrics, University of Kentucky College of Medicine, Lexington, KY 40536, USA.
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Park GB, Kim YS, Kim D, Kim S, Lee HK, Cho DH, Lee WJ, Hur DY. Melphalan-induced apoptosis of EBV-transformed B cells through upregulation of TAp73 and XAF1 and nuclear import of XPA. THE JOURNAL OF IMMUNOLOGY 2013; 191:6281-91. [PMID: 24249729 DOI: 10.4049/jimmunol.1203442] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Melphalan (Mel) is widely used to treat patients with hematologic cancer, including multiple myeloma, but its mechanism of action in EBV-transformed B cells is poorly described. In this study, we demonstrate a novel mechanism by which transcriptionally active p73 (TAp73) induces translocation of X-linked inhibitor of apoptosis protein-associated factor 1 (XAF1) and xeroderma pigmentosum group A (XPA) during apoptosis caused by Mel treatment. We observed that Mel induced significant generation of reactive oxygen species (ROS) and subsequent apoptosis, as well as an early phosphorylation of p38 MAPK that preceded expression of the mitochondria membrane potential disruption-related molecules and the cleavage of caspases. In particular, Mel led to upregulation of TAp73, XAF1, and Puma and induced XPA nuclear import and translocation of Bax into mitochondria. Mel-induced apoptosis was inhibited by pretreatment with the ROS scavenger 4-amino-2,4-pyrrolidine-dicarboxylic acid (APDC) and the p38 MAPK inhibitor SB203580. We supposed that ROS generation might be the first event in Mel-induced apoptosis, because APDC blocked the increase in ROS, p38 MAPK, and TAp73, but SB203580 did not block ROS generation. Moreover, Mel elicited activation of ATR, and APDC inhibited phosphorylation of ATR but not SB203580. APDC and SB203580 completely blocked XPA and Bax translocation. We conclude that Mel promotes TAp73-mediated XAF1 and Puma expression via ROS generation and ATR/p38 MAPK pathway activation, thereby triggering apoptosis. Our results provide evidence of a novel alternate regulatory mechanism of TAp73 and reveal that Mel may be a therapeutic drug for curing EBV-related malignancies.
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Affiliation(s)
- Ga Bin Park
- Department of Anatomy and Research Center for Tumor Immunology, Inje University College of Medicine, Busan 614-735, Republic of Korea
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Sirbu BM, Cortez D. DNA damage response: three levels of DNA repair regulation. Cold Spring Harb Perspect Biol 2013; 5:a012724. [PMID: 23813586 DOI: 10.1101/cshperspect.a012724] [Citation(s) in RCA: 174] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Genome integrity is challenged by DNA damage from both endogenous and environmental sources. This damage must be repaired to allow both RNA and DNA polymerases to accurately read and duplicate the information in the genome. Multiple repair enzymes scan the DNA for problems, remove the offending damage, and restore the DNA duplex. These repair mechanisms are regulated by DNA damage response kinases including DNA-PKcs, ATM, and ATR that are activated at DNA lesions. These kinases improve the efficiency of DNA repair by phosphorylating repair proteins to modify their activities, by initiating a complex series of changes in the local chromatin structure near the damage site, and by altering the overall cellular environment to make it more conducive to repair. In this review, we focus on these three levels of regulation to illustrate how the DNA damage kinases promote efficient repair to maintain genome integrity and prevent disease.
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Affiliation(s)
- Bianca M Sirbu
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37027, USA
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36
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UV-induced nuclear import of XPA is mediated by importin-α4 in an ATR-dependent manner. PLoS One 2013; 8:e68297. [PMID: 23861882 PMCID: PMC3704644 DOI: 10.1371/journal.pone.0068297] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Accepted: 05/28/2013] [Indexed: 12/29/2022] Open
Abstract
Xeroderma pigmentosum Group A (XPA) is a crucial factor in mammalian nucleotide excision repair (NER) and nuclear import of XPA from the cytoplasm for NER is regulated in cellular DNA damage responses in S-phase. In this study, experiments were carried out to determine the transport mechanisms that are responsible for the UV (ultraviolet)-induced nuclear import of XPA. We found that, in addition to the nuclear localization signal (NLS) of XPA, importin-α4 or/and importin-α7 are required for the XPA nuclear import. Further investigation indicated that, importin-α4 and importin-α7 directly interacted with XPA in cells. Interestingly, the binding of importin-α4 to XPA was dependent on UV-irradiation, while the binding of importin-α7 was not, suggesting a role for importin-α7 in nuclear translocation of XPA in the absence of DNA damage, perhaps with specificity to certain non-S-phases of the cell-cycle. Consistent with the previous report of a dependence of UV-induced XPA nuclear import on ataxia telangiectasia and Rad3-related protein (ATR) in S-phase, knockdown of ATR reduced the amount of XPA interacting with importin-α4. In contrast, the GTPase XPA binding protein 1 (XAB1), previously proposed to be required for XPA nuclear import, showed no effect on the nuclear import of XPA in our siRNA knockdown analysis. In conclusion, our results suggest that upon DNA damage transport adaptor importin-α4 imports XPA into the nucleus in an ATR-dependent manner, while XAB1 has no role in this process. In addition, these findings reveal a potential new therapeutic target for the sensitization of cancer cells to chemotherapy.
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37
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Guthrie OW, Xu H. Noise exposure potentiates the subcellular distribution of nucleotide excision repair proteins within spiral ganglion neurons. Hear Res 2012; 294:21-30. [DOI: 10.1016/j.heares.2012.09.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 09/05/2012] [Accepted: 09/06/2012] [Indexed: 01/08/2023]
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Lee TH, Park JM, Leem SH, Kang TH. Coordinated regulation of XPA stability by ATR and HERC2 during nucleotide excision repair. Oncogene 2012. [PMID: 23178497 DOI: 10.1038/onc.2012.539] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
ATR (ATM and Rad3-related) is an essential regulator of the nucleotide excision repair (NER) mechanism. For NER activation, ATR phosphorylates XPA, the rate-limiting factor in the NER pathway. However, the role of XPA phosphorylation at serine 196 by ATR has been elusive. Here we show that ATR-mediated XPA phosphorylation enhances XPA stability by inhibiting HERC2-mediated ubiquitination and subsequent degradation. We analyzed stabilization of XPA with substitutions of Ser 196 either to aspartate (S196D), a phosphomimetic mutation, or to alanine (S196A), a phosphodeficient mutation. Upon ultraviolet damage, ATR facilitated HERC2 dissociation from the XPA complex to induce XPA stabilization. However, this regulation was abrogated in S196A-complemented XPA-deficient cells due to persistent association of HERC2 with this XPA complex, resulting in enhanced ubiquitination of S196A. Conversely, the S196D substitution showed delayed degradation kinetics compared with the wild-type and less binding with HERC2, resulting in reduced ubiquitination of S196D. We also found that XPA phosphorylation enhanced the chromatin retention of XPA, the interaction with its binding partners following DNA damage. Taken together, our study presents a novel control mechanism in the NER pathway by regulating the steady-state level of XPA through posttranslational modifications by which ATR-mediated phosphorylation induces XPA stabilization by antagonizing HERC2-catalyzed XPA ubiquitination.
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Affiliation(s)
- T-H Lee
- Department of Biological Science, Dong-A University, Busan, Republic of Korea
| | - J-M Park
- Department of Biological Science, Dong-A University, Busan, Republic of Korea
| | - S-H Leem
- Department of Biological Science, Dong-A University, Busan, Republic of Korea
| | - T-H Kang
- Department of Biological Science, Dong-A University, Busan, Republic of Korea
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Bøe CA, Knutsen JHJ, Boye E, Grallert B. Hpz1 modulates the G1-S transition in fission yeast. PLoS One 2012; 7:e44539. [PMID: 22970243 PMCID: PMC3435320 DOI: 10.1371/journal.pone.0044539] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 08/03/2012] [Indexed: 11/29/2022] Open
Abstract
Here we characterize a novel protein in S. pombe. It has a high degree of homology with the Zn-finger domain of the human Poly(ADP-ribose) polymerase (PARP). Surprisingly, the gene for this protein is, in many fungi, fused with and in the same reading frame as that encoding Rad3, the homologue of the human ATR checkpoint protein. We name the protein Hpz1 (Homologue of PARP-type Zn-finger). Hpz1 does not possess PARP activity, but is important for resistance to ultraviolet light in the G1 phase and to treatment with hydroxyurea, a drug that arrests DNA replication forks in the S phase. However, we find no evidence of a checkpoint function of Hpz1. Furthermore, absence of Hpz1 results in an advancement of S-phase entry after a G1 arrest as well as earlier recovery from a hydroxyurea block. The hpz1 gene is expressed mainly in the G1 phase and Hpz1 is localized to the nucleus. We conclude that Hpz1 regulates the initiation of the S phase and may cooperate with Rad3 in this function.
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Affiliation(s)
- Cathrine A. Bøe
- Department of Cell Biology, Institute for Cancer Research, Oslo, Norway
- Institute for Molecular Biosciences, University of Oslo, Norway
| | - Jon Halvor J. Knutsen
- Department of Cell Biology, Institute for Cancer Research, Oslo, Norway
- Institute for Molecular Biosciences, University of Oslo, Norway
| | - Erik Boye
- Department of Cell Biology, Institute for Cancer Research, Oslo, Norway
- Institute for Molecular Biosciences, University of Oslo, Norway
| | - Beáta Grallert
- Department of Cell Biology, Institute for Cancer Research, Oslo, Norway
- Institute for Molecular Biosciences, University of Oslo, Norway
- * E-mail:
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Exposure to polycyclic aromatic hydrocarbons: bulky DNA adducts and cellular responses. EXPERIENTIA SUPPLEMENTUM (2012) 2012; 101:107-31. [PMID: 22945568 DOI: 10.1007/978-3-7643-8340-4_5] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Environmental and dietary carcinogens such as polycyclic aromatic hydrocarbons (PAHs) have been intensively studied for decades. Although the genotoxicity of these compounds is well characterized (i.e., formation of bulky PAH-DNA adducts), molecular details on the DNA damage response triggered by PAHs in cells and tissues remain to be clarified. The conversion of hazardous PAHs into carcinogenic intermediates depends on enzyme-catalyzed biotransformation. Certain cytochrome P450-dependent monooxygenases (CYPs) play a pivotal role in PAH metabolism. In particular, CYP1A1 and 1B1 catalyze oxidation of PAHs toward primary epoxide species that can further be converted into multiple follow-up products, both nonenzymatically and enzymatically. Distinct functions between these major CYP enzymes have only been appreciated since transgenic animal models had been derived. Electrophilic PAH metabolites are capable of forming stable DNA adducts or to promote depurination at damaged nucleotide sites. During the following DNA replication cycle, bulky PAH-DNA adducts may be converted into mutations, thereby affecting hot spot sites in regulatory important genes such as Ras, p53, and others. Depending on the degree of DNA distortion and cell cycle progression, PAH-DNA adducts trigger nucleotide excision repair (NER) and various DNA damage responses that might include TP53-dependent apoptosis in certain cell types. In fact, cellular responses to bulky PAH-DNA damage are complex because distinct signaling branches such as ATM/ATR, NER, TP53, but also MAP kinases, interact and cooperate to determine the overall outcome to cellular injuries initiated by PAH-DNA adducts. Further, PAHs and other xenobiotics can also confer DNA damage via an alternative route of metabolic activation, which leads to the generation of PAH semiquinone radicals and reactive oxygen species (ROS). One-electron oxidations mediated by peroxidases or other enzymes can result in PAH radical cations that mainly form unstable DNA adducts subjected to depurination. In addition, generation of ROS can also trigger multiple cellular signaling pathways not directly related to mutagenic or cytotoxic effects, including those mediated by NFκB, SAPK/JNK, and p38. In recent years, it became clear that PAHs may also be involved in inflammatory diseases, autoimmune disorders, or atherosclerosis. Further research is under way to better characterize the significance of such newly recognized systemic effects of PAHs and to reconsider risk assessment for human health.
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XPA-mediated regulation of global nucleotide excision repair by ATR Is p53-dependent and occurs primarily in S-phase. PLoS One 2011; 6:e28326. [PMID: 22174788 PMCID: PMC3236200 DOI: 10.1371/journal.pone.0028326] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Accepted: 11/05/2011] [Indexed: 12/30/2022] Open
Abstract
Cell cycle checkpoints play an important role in regulation of DNA repair pathways. However, how the regulation occurs throughout the cell cycle remains largely unknown. Here we demonstrate that nucleotide excision repair (NER) is regulated by the ATR/p53 checkpoint via modulation of XPA nuclear import and that this regulation occurs in a cell cycle-dependent manner. We show that depletion of p53 abrogated the UV-induced nuclear translocation of XPA, while silencing of Chk1 or MAPKAP Kinase-2 (MK2) had no effect. Inhibition of p53 transcriptional activities and silencing of p53-Ser15 phosphorylation also reduced the damage-induced XPA nuclear import. Furthermore, in G1-phase cells the majority of XPA remained in the cytoplasm even after UV treatment. By contrast, while most of the XPA in S-phase cells was initially located in the cytoplasm before DNA damage, UV irradiation stimulated bulk import of XPA into the nucleus. Interestingly, the majority of XPA molecules always were located in the nucleus in G2-phase cells no matter whether the DNA was damaged or not. Consistently, the UV-induced Ser15 phosphorylation of p53 occurred mainly in S-phase cells, and removal of cyclobutane pyrimidine dimers (CPDs) was much more efficient in S-phase cells than in G1-phase cells. Our results suggest that upon DNA damage in S phase, NER could be regulated by the ATR/p53-dependent checkpoint via modulation of the XPA nuclear import process. In contrast, the nuclear import of XPA in G(1) or G(2) phase appears to be largely independent of DNA damage and p53.
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Pascucci B, D'Errico M, Parlanti E, Giovannini S, Dogliotti E. Role of nucleotide excision repair proteins in oxidative DNA damage repair: an updating. BIOCHEMISTRY (MOSCOW) 2011; 76:4-15. [PMID: 21568835 DOI: 10.1134/s0006297911010032] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
DNA repair is a crucial factor in maintaining a low steady-state level of oxidative DNA damage. Base excision repair (BER) has an important role in preventing the deleterious effects of oxidative DNA damage, but recent evidence points to the involvement of several repair pathways in this process. Oxidative damage may arise from endogenous and exogenous sources and may target nuclear and mitochondrial DNA as well as RNA and proteins. The importance of preventing mutations associated with oxidative damage is shown by a direct association between defects in BER (i.e. MYH DNA glycosylase) and colorectal cancer, but it is becoming increasingly evident that damage by highly reactive oxygen species plays also central roles in aging and neurodegeneration. Mutations in genes of the nucleotide excision repair (NER) pathway are associated with diseases, such as xeroderma pigmentosum and Cockayne syndrome, that involve increased skin cancer and/or developmental and neurological symptoms. In this review we will provide an updating of the current evidence on the involvement of NER factors in the control of oxidative DNA damage and will attempt to address the issue of whether this unexpected role may unlock the difficult puzzle of the pathogenesis of these syndromes.
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Affiliation(s)
- B Pascucci
- Istituto di Cristallografia, Consiglio Nazionale delle Ricerche, Monterotondo Stazione, Rome, Italy.
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Rechkunova NI, Krasikova YS, Lavrik OI. Nucleotide excision repair: DNA damage recognition and preincision complex assembly. BIOCHEMISTRY (MOSCOW) 2011; 76:24-35. [PMID: 21568837 DOI: 10.1134/s0006297911010056] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Nucleotide excision repair (NER) is one of the major DNA repair pathways in eukaryotic cells counteracting genetic changes caused by DNA damage. NER removes a wide set of structurally diverse lesions such as pyrimidine dimers arising upon UV irradiation and bulky chemical adducts arising upon exposure to carcinogens or chemotherapeutic drugs. NER defects lead to severe diseases including some forms of cancer. In view of the broad substrate specificity of NER, it is of interest to understand how a certain set of proteins recognizes various DNA lesions in the context of a large excess of intact DNA. This review focuses on DNA damage recognition and following stages resulting in preincision complex assembly, the key and still most unclear steps of NER. The major models of primary damage recognition and preincision complex assembly are considered. The contribution of affinity labeling techniques in study of this process is discussed.
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Affiliation(s)
- N I Rechkunova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia.
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The role of XPC: implications in cancer and oxidative DNA damage. Mutat Res 2011; 728:107-17. [PMID: 21763452 DOI: 10.1016/j.mrrev.2011.07.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Revised: 06/30/2011] [Accepted: 07/01/2011] [Indexed: 01/14/2023]
Abstract
The accumulation of DNA damage is a slow but hazardous phenomenon that may lead to cell death, accelerated aging features and cancer. One of the most versatile and important defense mechanisms against the accumulation of DNA damage is nucleotide excision repair (NER), in which the Xeroderma pigmentosum group C (XPC) protein plays a prominent role. NER can be divided into global genome repair (GG-NER) and transcription coupled repair (TC-NER). XPC is a key factor in GG-NER where it functions in DNA damage recognition and after which the repair machinery is recruited to eliminate the DNA damage. Defective XPC functioning has been shown to result in a cancer prone phenotype, in human as well as in mice. Mutation accumulation in XPC deficient mice is accelerated and increased, resulting in an increased tumor incidence. More recently XPC has also been linked to functions outside of NER since XPC deficient mice show a divergent tumor spectrum compared to other NER deficient mouse models. Multiple in vivo and in vitro experiments indicate that XPC appears to be involved in the initiation of several DNA damage-induced cellular responses. XPC seems to function in the removal of oxidative DNA damage, redox homeostasis and cell cycle control. We hypothesize that this combination of increased oxidative DNA damage sensitivity, disturbed redox homeostasis together with inefficient cell cycle control mechanisms are causes of the observed increased cancer susceptibility in oxygen exposed tissues. Such a phenotype is absent in other NER-deficient mice, including Xpa.
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Novarina D, Amara F, Lazzaro F, Plevani P, Muzi-Falconi M. Mind the gap: keeping UV lesions in check. DNA Repair (Amst) 2011; 10:751-9. [PMID: 21602108 PMCID: PMC3171152 DOI: 10.1016/j.dnarep.2011.04.030] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Cells respond to genotoxic insults by triggering a DNA damage checkpoint surveillance mechanism and by activating repair pathways. Recent findings indicate that the two processes are more related than originally thought. Here we discuss the mechanisms involved in responding to UV-induced lesions in different phases of the cell cycle and summarize the most recent data in a model where Nucleotide Excision Repair (NER) and exonucleolytic activities act in sequence leading to checkpoint activation in non replicating cells. The critical trigger is likely represented by problematic intermediates that cannot be completely or efficiently repaired by NER. In S phase cells, on the other hand, the replicative polymerases, blocked by bulky UV lesions, re-initiate DNA synthesis downstream of the lesions, leaving behind a ssDNA tract. If these gaps are not rapidly refilled, checkpoint kinases will be activated.
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Affiliation(s)
- Daniele Novarina
- Dipartimento di Scienze Biomolecolari e Biotecnologie, Università degli Studi di Milano. Via Celoria 26, 20133 Milano, Italy
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Ha K, Fiskus W, Rao R, Balusu R, Venkannagari S, Nalabothula NR, Bhalla KN. Hsp90 inhibitor-mediated disruption of chaperone association of ATR with hsp90 sensitizes cancer cells to DNA damage. Mol Cancer Ther 2011; 10:1194-206. [PMID: 21566061 DOI: 10.1158/1535-7163.mct-11-0094] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Following DNA damage that results in stalled replication fork, activation of ATR-CHK1 signaling induces the DNA damage response (DDR) in transformed cells. In the present studies on human cervical and breast cancer cells, we determined the effects of hsp90 inhibition on the levels and accumulation of DNA damage/repair-associated proteins following exposure to γ-ionizing radiation (IR; 4 Gy). We show that hsp90 inhibition with 17-allylamino-demehoxygeldanamycin or the novel, nongeldanamycin analogue AUY922 (resorcinylic isoxazole amide; Novartis Pharma) dose-dependently reduced the levels of ATR and CHK1 without affecting ATM levels. AUY922-mediated depletion of ATR and CHK1 was associated with an increase in their polyubiquitylation and decreased binding to hsp90. Cotreatment with bortezomib partially restored AUY922-mediated depletion of ATR and CHK1 levels. Additionally, treatment with AUY922 reduced the accumulation of ATR, p53BP1, and CHK1 but not γ-H2AX to the sites of DNA damage. Following exposure to IR, AUY922 treatment abrogated IR-induced phospho (p)-ATR and p-CHK1 levels, but significantly enhanced γ-H2AX levels. AUY922 treatment also increased IR-induced accumulation of the cells in G(2)-M phase of the cell cycle, inhibited the repair of IR-induced DNA damage, and augmented IR-mediated loss of clonogenic survival. Short hairpin RNA-mediated depletion of ATR also inhibited IR-induced p-ATR and p-CHK1, but increased γ-H2AX levels, sensitizing cancer cells to IR-induced apoptosis and loss of clonogenic survival. These findings indicate that ATR is a bona fide hsp90 client protein and post-IR administration of AUY922, by inhibiting ATR-CHK1-mediated DDR, sensitizes cancer cells to IR.
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Affiliation(s)
- Kyungsoo Ha
- Medical College of Georgia, Augusta, Georgia, USA
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Li Z, Musich PR, Zou Y. Differential DNA damage responses in p53 proficient and deficient cells: cisplatin-induced nuclear import of XPA is independent of ATR checkpoint in p53-deficient lung cancer cells. INTERNATIONAL JOURNAL OF BIOCHEMISTRY AND MOLECULAR BIOLOGY 2011; 2:138-145. [PMID: 21643554 PMCID: PMC3107498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Accepted: 03/23/2011] [Indexed: 05/30/2023]
Abstract
Nucleotide excision repair (NER) and ataxia telangiectasia mutated (ATM)/ATR (ATM- and RAD3-related) DNA damage checkpoints are among the major pathways that affect the chemotherapeutic efficiency of the anticancer drug cisplatin. Xeroderma pigmentosum group A (XPA) protein plays a crucial role in NER including both global genome repair (GG-NER) and transcription-coupled repair (TC-NER) subpathways, and has been a potential target for improving cisplatin therapeutic effects. We report here that XPA translocates from the cytosol into the nucleus after DNA damage induced by UV irradiation and cisplatin, a mimetic of UV damage, in human cells with or without p53 deficiency. However, the damage-induced response of XPA nuclear import was significantly slower in p53-deficient cells than in p53-proficient cells. We also found that while XPA is imported into the nucleus upon cisplatin or UV damage in an ATR-dependent manner in p53-proficient A549 lung cancer cells, the ATR checkpoint pathway has no effect on the XPA nuclear import in p53-deficient H1299 lung cancer cells. Similarly, the XPA nuclear translocation is not regulated by ATM checkpoint or by p38MAPK/MK2 either. Our findings suggest that NER is independent on the major DNA damage checkpoint pathways in H1299 (p53(-/-)) cells and that DNA damage responses are mechanistically different between p53-proficient and p53-deficient cells. Our results also highlight the possibility of selectively targeting XPA nuclear import as a way to sensitize cisplatin anticancer activity, but targeting ATR/ATM-dependent checkpoints may not be helpful in killing p53-deficient cancer cells.
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Affiliation(s)
- Zhengke Li
- Department of Biochemistry and Molecular Biology East Tennessee State University, J.H Quillen College of Medicine, Johnson City, Tennessee 37614, USA
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Abstract
OBJECTIVE Human mutations in the DNA repair genes, Xeroderma pigmentosum (XP)-C and XPA result in hearing loss, which has fueled the hypothesis that there is a significant demand for these genes in protecting cochlear genetic material. Therefore, we quantified the level of XPC and XPA mRNA in the mammalian cochlea. DESIGN XPC and XPA mRNAs were purified from the cochlea of 15 Fischer344 rats and quantified using SYBR Green chemistry. Another 15 Fischer344 rats were sacrificed for immunolocalization of XPC and XPA polypeptides in the cochlea and kidney (control organ). RESULTS XP mRNA levels were up to 95% (XPA) and 69% (XPC) of the respective maximum expression capacity of each gene. In addition, these cochlear levels were up to sixfold (XPC) and threefold (XPA) greater than that of the kidney, which is known to exhibit XP-DNA repair activity that is greater than most organs of the body. Immunohistochemistry revealed that most kidney and cochlear cells were immunopositive. CONCLUSION These data suggest that under normal conditions the cochlea is experiencing persistent genomic stress that helps to explain the hypersensitivity of the cochlea to exogenous stressors (ototoxic xenobiotics and/or acoustic-overexposure) as well as provide a basis to interpret hearing loss among patients with XP.
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Vaid M, Sharma SD, Katiyar SK. Proanthocyanidins inhibit photocarcinogenesis through enhancement of DNA repair and xeroderma pigmentosum group A-dependent mechanism. Cancer Prev Res (Phila) 2010; 3:1621-9. [PMID: 20947490 DOI: 10.1158/1940-6207.capr-10-0137] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Dietary grape seed proanthocyanidins (GSP) inhibit photocarcinogenesis in mice; however, the molecular mechanisms underlying this effect have not been fully elucidated. As ultraviolet B (UVB)-induced DNA damage in the form of cyclobutane pyrimidine dimers (CPDs) has been implicated in skin cancer risk, we studied whether dietary GSPs enhance repair of UVB-induced DNA damage and, if so, what is the potential mechanism? Supplementation of GSPs (0.5%, w/w) with AIN76A control diet significantly reduced the levels of CPD(+) cells in UVB-exposed mouse skin; however, GSPs did not significantly reduce UVB-induced CPD(+) cells in the skin of interleukin-12p40 (IL-12) knockout (KO) mice, suggesting that IL-12 is required for the repair of CPDs by GSPs. Using IL-12 KO mice and their wild-type counterparts and standard photocarcinogenesis protocol, we found that supplementation of control diet with GSPs (0.5%, w/w) significantly reduced UVB-induced skin tumor development in wild-type mice, which was associated with the elevated mRNA levels of nucleotide excision repair genes, such as XPA, XPC, DDB2, and RPA1; however, this effect of GSPs was less pronounced in IL-12 KO mice. Cytostaining analysis revealed that GSPs repaired UV-induced CPD(+) cells in xeroderma pigmentosum complementation group A (XPA)-proficient fibroblasts from a healthy individual but did not repair in XPA-deficient fibroblasts from XPA patients. Furthermore, GSPs enhance nuclear translocation of XPA and enhanced its interactions with other DNA repair protein ERCC1. Together, our findings reveal that prevention of photocarcinogenesis by GSPs is mediated through enhanced DNA repair in epidermal cells by IL-12- and XPA-dependent mechanisms.
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Affiliation(s)
- Mudit Vaid
- Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Ljungman M. The DNA damage response--repair or despair? ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2010; 51:879-889. [PMID: 20818630 DOI: 10.1002/em.20597] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The term "the DNA damage response" (DDR) encompasses a sophisticated array of cellular initiatives set in motion as cells are exposed to DNA-damaging events. It has been known for over half a century that all organisms have the ability to restore genomic integrity through DNA repair. More recent discoveries of signal transduction pathways linking DNA damage to cell cycle arrest and apoptosis have greatly expanded our views of how cells and tissues limit mutagenesis and tumorigenesis. DNA repair not only plays a pivotal role in suppressing mutagenesis but also in the reversal of signals inducing the stress response. If repair is faulty or the cell is overwhelmed by damage, chances are that the cell will despair and be removed by apoptosis. This final fate is determined by intricate cellular dosimeters that are yet to be fully understood. Here, key findings leading to our current view of DDR are discussed as well as potential areas of importance for future studies.
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Affiliation(s)
- Mats Ljungman
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, University of Michigan Comprehensive Cancer Center, Ann Arbor, Michigan 48109, USA.
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