1
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Clausse V, Fang Y, Tao D, Tagad HD, Sun H, Wang Y, Karavadhi S, Lane K, Shi ZD, Vasalatiy O, LeClair CA, Eells R, Shen M, Patnaik S, Appella E, Coussens NP, Hall MD, Appella DH. Discovery of Novel Small-Molecule Scaffolds for the Inhibition and Activation of WIP1 Phosphatase from a RapidFire Mass Spectrometry High-Throughput Screen. ACS Pharmacol Transl Sci 2022; 5:993-1006. [PMID: 36268125 PMCID: PMC9578142 DOI: 10.1021/acsptsci.2c00147] [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: 07/18/2022] [Indexed: 11/28/2022]
Abstract
Wild-type P53-induced phosphatase 1 (WIP1), also known as PPM1D or PP2Cδ, is a serine/threonine protein phosphatase induced by P53 after genotoxic stress. WIP1 inhibition has been proposed as a therapeutic strategy for P53 wild-type cancers in which it is overexpressed, but this approach would be ineffective in P53-negative cancers. Furthermore, there are several cancers with mutated P53 where WIP1 acts as a tumor suppressor. Therefore, activating WIP1 phosphatase might also be a therapeutic strategy, depending on the P53 status. To date, no specific, potent WIP1 inhibitors with appropriate pharmacokinetic properties have been reported, nor have WIP1-specific activators. Here, we report the discovery of new WIP1 modulators from a high-throughput screen (HTS) using previously described orthogonal biochemical assays suitable for identifying both inhibitors and activators. The primary HTS was performed against a library of 102 277 compounds at a single concentration using a RapidFire mass spectrometry assay. Hits were further evaluated over a range of 11 concentrations with both the RapidFire MS assay and an orthogonal fluorescence-based assay. Further biophysical, biochemical, and cell-based studies of confirmed hits revealed a WIP1 activator and two inhibitors, one competitive and one uncompetitive. These new scaffolds are prime candidates for optimization which might enable inhibitors with improved pharmacokinetics and a first-in-class WIP1 activator.
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Affiliation(s)
- Victor Clausse
- Synthetic
Bioactive Molecules Section, Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Yuhong Fang
- National
Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850, United States
| | - Dingyin Tao
- National
Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850, United States
| | - Harichandra D. Tagad
- Laboratory
of Cell Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Hongmao Sun
- National
Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850, United States
| | - Yuhong Wang
- National
Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850, United States
| | - Surendra Karavadhi
- National
Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850, United States
| | - Kelly Lane
- Chemistry
and Synthesis Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Rockville, Maryland 20850, United States
| | - Zhen-Dan Shi
- Chemistry
and Synthesis Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Rockville, Maryland 20850, United States
| | - Olga Vasalatiy
- Chemistry
and Synthesis Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Rockville, Maryland 20850, United States
| | - Christopher A. LeClair
- National
Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850, United States
| | - Rebecca Eells
- Reaction
Biology Corporation, 1 Great Valley Parkway, Suite 2, Malvern, Pennsylvania 19355, United States
| | - Min Shen
- National
Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850, United States
| | - Samarjit Patnaik
- National
Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850, United States
| | - Ettore Appella
- Laboratory
of Cell Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Nathan P. Coussens
- Molecular
Pharmacology Laboratories, Applied and Developmental Research Directorate, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
| | - Matthew D. Hall
- National
Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850, United States
| | - Daniel H. Appella
- Synthetic
Bioactive Molecules Section, Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, Bethesda, Maryland 20892, United States
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2
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Allosteric inhibition of PPM1D serine/threonine phosphatase via an altered conformational state. Nat Commun 2022; 13:3778. [PMID: 35773251 PMCID: PMC9246869 DOI: 10.1038/s41467-022-30463-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 05/02/2022] [Indexed: 02/02/2023] Open
Abstract
PPM1D encodes a serine/threonine phosphatase that regulates numerous pathways including the DNA damage response and p53. Activating mutations and amplification of PPM1D are found across numerous cancer types. GSK2830371 is a potent and selective allosteric inhibitor of PPM1D, but its mechanism of binding and inhibition of catalytic activity are unknown. Here we use computational, biochemical and functional genetic studies to elucidate the molecular basis of GSK2830371 activity. These data confirm that GSK2830371 binds an allosteric site of PPM1D with high affinity. By further incorporating data from hydrogen deuterium exchange mass spectrometry and sedimentation velocity analytical ultracentrifugation, we demonstrate that PPM1D exists in an equilibrium between two conformations that are defined by the movement of the flap domain, which is required for substrate recognition. A hinge region was identified that is critical for switching between the two conformations and was directly implicated in the high-affinity binding of GSK2830371 to PPM1D. We propose that the two conformations represent active and inactive forms of the protein reflected by the position of the flap, and that binding of GSK2830371 shifts the equilibrium to the inactive form. Finally, we found that C-terminal truncating mutations proximal to residue 400 result in destabilization of the protein via loss of a stabilizing N- and C-terminal interaction, consistent with the observation from human genetic data that nearly all PPM1D mutations in cancer are truncating and occur distal to residue 400. Taken together, our findings elucidate the mechanism by which binding of a small molecule to an allosteric site of PPM1D inhibits its activity and provides insights into the biology of PPM1D.
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3
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He W, Zhang Y, Cao Z, Ye Z, Lu X, Fan J, Peng W, Li Z. Wild-Type p53-Induced Phosphatase 1 Plays a Positive Role in Hematopoiesis in the Mouse Embryonic Head. Front Cell Dev Biol 2021; 9:732527. [PMID: 34604235 PMCID: PMC8484912 DOI: 10.3389/fcell.2021.732527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 08/18/2021] [Indexed: 12/02/2022] Open
Abstract
The first adult repopulating hematopoietic stem cells (HSCs) are found in the aorta-gonad-mesonephros (AGM) region, which are produced from hemogenic endothelial cells. Embryonic head is the other site for HSC development. Wild-type p53-induced phosphatase 1 (Wip1) is a type-2Cδ family serine/threonine phosphatase involved in various cellular processes such as lymphoid development and differentiation of adult HSCs. Most recently, we have shown that Wip1 modulates the pre-HSC maturation in the AGM region. However, it is not clear whether Wip1 regulates hematopoiesis in the embryonic head. Here we reported that disruption of Wip1 resulted in a decrease of hematopoietic progenitor cell number in the embryonic head. In vivo transplantation assays showed a reduction of HSC function after Wip1 ablation. We established that Wip1 deletion reduced the frequency and cell number of microglia in the embryonic head. Further observations revealed that Wip1 absence enhanced the gene expression of microglia-derived pro-inflammatory factors. Thus, it is likely that Wip1 functions as a positive regulator in HSC development by regulating the function of microglia in the embryonic head.
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Affiliation(s)
- Wenyan He
- China National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Ying Zhang
- Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Zhan Cao
- Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Zehua Ye
- Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Xun Lu
- Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Junwan Fan
- China National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Wei Peng
- Department of Stomatology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Zhuan Li
- Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
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4
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Ye L, Song Z, Li C. Landscape and flux quantify the stochastic transition dynamics for p53 cell fate decision. J Chem Phys 2021; 154:025101. [PMID: 33445890 DOI: 10.1063/5.0030558] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The p53 transcription factor is a key mediator in cellular responses to various stress signals including DNA repair, cell cycle arrest, and apoptosis. In this work, we employ landscape and flux theory to investigate underlying mechanisms of p53-regulated cell fate decisions. Based on a p53 regulatory network, we quantified the potential landscape and probabilistic flux for the p53 system. The landscape topography unifies and quantifies three cell fate states, including the limit cycle oscillations (representing cell cycle arrest), high p53 state (characterizing apoptosis), and low p53 state (characterizing the normal proliferative state). Landscape and flux results provide a quantitative explanation for the biphasic dynamics of the p53 system. In the oscillatory phase (first phase), the landscape attracts the system into the ring valley and flux drives the system cyclically moving, leading to cell cycle arrest. In the fate decision-making phase (second phase), the ring valley shape of the landscape provides an efficient way for cells to return to the normal proliferative state once DNA damage is repaired. If the damage is unrepairable with larger flux, the system may cross the barrier between two states and switch to the apoptotic state with a high p53 level. By landscape-flux decomposition, we revealed a trade-off between stability (guaranteed by landscape) and function (driven by flux) in cellular systems. Cells need to keep a balance between appropriate speed to repair DNA damage and appropriate stability to survive. This is further supported by flux landscape analysis showing that flux may provide the dynamical origin of phase transition in a non-equilibrium system by changing landscape topography.
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Affiliation(s)
- Leijun Ye
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
| | - Zhuoqing Song
- Shanghai Center for Mathematical Sciences, Fudan University, Shanghai, China
| | - Chunhe Li
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
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5
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Phosphatase magnesium-dependent 1 δ (PPM1D), serine/threonine protein phosphatase and novel pharmacological target in cancer. Biochem Pharmacol 2020; 184:114362. [PMID: 33309518 DOI: 10.1016/j.bcp.2020.114362] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 12/04/2020] [Accepted: 12/07/2020] [Indexed: 12/20/2022]
Abstract
Aberrations in DNA damage response genes are recognized mediators of tumorigenesis and resistance to chemo- and radiotherapy. While protein phosphatase magnesium-dependent 1 δ (PPM1D), located on the long arm of chromosome 17 at 17q22-23, is a key regulator of cellular responses to DNA damage, amplification, overexpression, or mutation of this gene is important in a wide range of pathologic processes. In this review, we describe the physiologic function of PPM1D, as well as its role in diverse processes, including fertility, development, stemness, immunity, tumorigenesis, and treatment responsiveness. We highlight both the advances and limitations of current approaches to targeting malignant processes mediated by pathogenic alterations in PPM1D with the goal of providing rationale for continued research and development of clinically viable treatment approaches for PPM1D-associated diseases.
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6
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Shi L, Tian Q, Feng C, Zhang P, Zhao Y. The biological function and the regulatory roles of wild-type p53-induced phosphatase 1 in immune system. Int Rev Immunol 2020; 39:280-291. [PMID: 32696682 DOI: 10.1080/08830185.2020.1795153] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Wild-type p53-induced phosphatase 1 (WIP1) belongs to the protein phosphatase 2C (PP2C) family and is a mammalian serine/threonine specific protein phosphatase to dephosphorylate numerous signaling molecules. Mammalian WIP1 regulates a wide array of targeting molecules and plays key regulatory roles in many cell processes such as DNA damage and repair, cell proliferation, differentiation, apoptosis, and senescence. WIP1 promotes the formation and development of tumors as an oncogene and a negative regulator of p53. It is also involved in the regulation of aging, neurological diseases and immune diseases. Recent studies demonstrated the critical roles of WIP1 in the differentiation and function of immune cells including T cells, neutrophils and macrophages. In the present manuscript, we briefly summarized the expression patterns, biological function and the target molecules and signal pathways of WIP1 and mainly discussed the latest advances on the regulatory effects of WIP1 in the immune system. WIP1 may be a potential target molecule to treat cancers and immune diseases such as allergic asthma.
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Affiliation(s)
- Lu Shi
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Qianchuan Tian
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Chang Feng
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Peng Zhang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yong Zhao
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China.,Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China
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7
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Metal-dependent Ser/Thr protein phosphatase PPM family: Evolution, structures, diseases and inhibitors. Pharmacol Ther 2020; 215:107622. [PMID: 32650009 DOI: 10.1016/j.pharmthera.2020.107622] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 06/29/2020] [Indexed: 02/06/2023]
Abstract
Protein phosphatases and kinases control multiple cellular events including proliferation, differentiation, and stress responses through regulating reversible protein phosphorylation, the most important post-translational modification. Members of metal-dependent protein phosphatase (PPM) family, also known as PP2C phosphatases, are Ser/Thr phosphatases that bind manganese/magnesium ions (Mn2+/Mg2+) in their active center and function as single subunit enzymes. In mammals, there are 20 isoforms of PPM phosphatases: PPM1A, PPM1B, PPM1D, PPM1E, PPM1F, PPM1G, PPM1H, PPM1J, PPM1K, PPM1L, PPM1M, PPM1N, ILKAP, PDP1, PDP2, PHLPP1, PHLPP2, PP2D1, PPTC7, and TAB1, whereas there are only 8 in yeast. Phylogenetic analysis of the DNA sequences of vertebrate PPM isoforms revealed that they can be divided into 12 different classes: PPM1A/PPM1B/PPM1N, PPM1D, PPM1E/PPM1F, PPM1G, PPM1H/PPM1J/PPM1M, PPM1K, PPM1L, ILKAP, PDP1/PDP2, PP2D1/PHLPP1/PHLPP2, TAB1, and PPTC7. PPM-family members have a conserved catalytic core region, which contains the metal-chelating residues. The different isoforms also have isoform specific regions within their catalytic core domain and terminal domains, and these regions may be involved in substrate recognition and/or functional regulation of the phosphatases. The twenty mammalian PPM phosphatases are involved in regulating diverse cellular functions, such as cell cycle control, cell differentiation, immune responses, and cell metabolism. Mutation, overexpression, or deletion of the PPM phosphatase gene results in abnormal cellular responses, which lead to various human diseases. This review focuses on the structures and biological functions of the PPM-phosphatase family and their associated diseases. The development of specific inhibitors against the PPM phosphatase family as a therapeutic strategy will also be discussed.
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8
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Deng W, Li J, Dorrah K, Jimenez-Tapia D, Arriaga B, Hao Q, Cao W, Gao Z, Vadgama J, Wu Y. The role of PPM1D in cancer and advances in studies of its inhibitors. Biomed Pharmacother 2020; 125:109956. [PMID: 32006900 DOI: 10.1016/j.biopha.2020.109956] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 01/08/2020] [Accepted: 01/23/2020] [Indexed: 12/16/2022] Open
Abstract
A greater understanding of factors causing cancer initiation, progression and evolution is of paramount importance. Among them, the serine/threonine phosphatase PPM1D, also referred to as wild-type p53-induced phosphatase 1 (Wip1) or protein phosphatase 2C delta (PP2Cδ), is emerging as an important oncoprotein due to its negative regulation on a number of crucial cancer suppressor pathways. Initially identified as a p53-regulated gene, PPM1D has been afterwards found amplified and more recently mutated in many human cancers such as breast cancer. The latest progress in this field further reveals that selective inhibition of PPM1D to delay tumor onset or reduce tumor burden represents a promising anti-cancer strategy. Here, we review the advances in the studies of the PPM1D activity and its relevance to various cancers, and recent progress in development of PPM1D inhibitors and discuss their potential application in cancer therapy. Consecutive research on PPM1D and its relationship with cancer is essential, as it ultimately contributes to the etiology and treatment of cancer.
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Affiliation(s)
- Wenhong Deng
- Department of General Surgery, Renmin Hospital of Wuhan University, Wuhan, 430060, China; Division of Cancer Research and Training, Department of Internal Medicine, Charles Drew University of Medicine and Science, David Geffen UCLA School of Medicine and UCLA Jonsson Comprehensive Cancer Center, Los Angeles, CA, USA
| | - Jieqing Li
- Division of Cancer Research and Training, Department of Internal Medicine, Charles Drew University of Medicine and Science, David Geffen UCLA School of Medicine and UCLA Jonsson Comprehensive Cancer Center, Los Angeles, CA, USA
| | - Kimberly Dorrah
- Division of Cancer Research and Training, Department of Internal Medicine, Charles Drew University of Medicine and Science, David Geffen UCLA School of Medicine and UCLA Jonsson Comprehensive Cancer Center, Los Angeles, CA, USA
| | - Denise Jimenez-Tapia
- Division of Cancer Research and Training, Department of Internal Medicine, Charles Drew University of Medicine and Science, David Geffen UCLA School of Medicine and UCLA Jonsson Comprehensive Cancer Center, Los Angeles, CA, USA
| | - Brando Arriaga
- Division of Cancer Research and Training, Department of Internal Medicine, Charles Drew University of Medicine and Science, David Geffen UCLA School of Medicine and UCLA Jonsson Comprehensive Cancer Center, Los Angeles, CA, USA
| | - Qiongyu Hao
- Division of Cancer Research and Training, Department of Internal Medicine, Charles Drew University of Medicine and Science, David Geffen UCLA School of Medicine and UCLA Jonsson Comprehensive Cancer Center, Los Angeles, CA, USA
| | - Wei Cao
- Division of Cancer Research and Training, Department of Internal Medicine, Charles Drew University of Medicine and Science, David Geffen UCLA School of Medicine and UCLA Jonsson Comprehensive Cancer Center, Los Angeles, CA, USA
| | - Zhaoxia Gao
- Department of General Surgery, 5th Hospital of Wuhan, Wuhan, 430050, China; Department of Surgery, Johns Hopkins Hospital Bayview Campus, Baltimore, MD, USA
| | - Jay Vadgama
- Division of Cancer Research and Training, Department of Internal Medicine, Charles Drew University of Medicine and Science, David Geffen UCLA School of Medicine and UCLA Jonsson Comprehensive Cancer Center, Los Angeles, CA, USA.
| | - Yong Wu
- Division of Cancer Research and Training, Department of Internal Medicine, Charles Drew University of Medicine and Science, David Geffen UCLA School of Medicine and UCLA Jonsson Comprehensive Cancer Center, Los Angeles, CA, USA.
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Li Q, Hao Q, Cao W, Li J, Wu K, Elshimali Y, Zhu D, Chen QH, Chen G, Pollack JR, Vadgama J, Wu Y. PP2Cδ inhibits p300-mediated p53 acetylation via ATM/BRCA1 pathway to impede DNA damage response in breast cancer. SCIENCE ADVANCES 2019; 5:eaaw8417. [PMID: 31663018 PMCID: PMC6795508 DOI: 10.1126/sciadv.aaw8417] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 09/19/2019] [Indexed: 06/10/2023]
Abstract
Although nuclear type 2C protein phosphatase (PP2Cδ) has been demonstrated to be pro-oncogenic with an important role in tumorigenesis, the underlying mechanisms that link aberrant PP2Cδ levels with cancer development remain elusive. Here, we found that aberrant PP2Cδ activity decreases p53 acetylation and its transcriptional activity and suppresses doxorubicin-induced cell apoptosis. Mechanistically, we show that BRCA1 facilitates p300-mediated p53 acetylation by complexing with these two proteins and that S1423/1524 phosphorylation is indispensable for this regulatory process. PP2Cδ, via dephosphorylation of ATM, suppresses DNA damage-induced BRCA1 phosphorylation, leading to inhibition of p300-mediated p53 acetylation. Furthermore, PP2Cδ levels correlate with histological grade and are inversely associated with BRCA1 phosphorylation and p53 acetylation in breast cancer specimens. C23, our newly developed PP2Cδ inhibitor, promotes the anticancer effect of doxorubicin in MCF-7 xenograft-bearing nude mice. Together, our data indicate that PP2Cδ impairs p53 acetylation and DNA damage response by compromising BRCA1 function.
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Affiliation(s)
- Qun Li
- Department of Oncology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
- Department of Oncology, Shanghai Cancer Center and Shanghai Medical College, Fudan University, Shanghai 200032, China
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Qiongyu Hao
- Division of Cancer Research and Training, Department of Internal Medicine, Charles Drew University of Medicine and Science, David Geffen UCLA School of Medicine and UCLA Jonsson Comprehensive Cancer Center, Los Angeles, CA 90059, USA
| | - Wei Cao
- Division of Cancer Research and Training, Department of Internal Medicine, Charles Drew University of Medicine and Science, David Geffen UCLA School of Medicine and UCLA Jonsson Comprehensive Cancer Center, Los Angeles, CA 90059, USA
| | - Jieqing Li
- Division of Cancer Research and Training, Department of Internal Medicine, Charles Drew University of Medicine and Science, David Geffen UCLA School of Medicine and UCLA Jonsson Comprehensive Cancer Center, Los Angeles, CA 90059, USA
| | - Ke Wu
- Division of Cancer Research and Training, Department of Internal Medicine, Charles Drew University of Medicine and Science, David Geffen UCLA School of Medicine and UCLA Jonsson Comprehensive Cancer Center, Los Angeles, CA 90059, USA
| | - Yahya Elshimali
- Division of Cancer Research and Training, Department of Internal Medicine, Charles Drew University of Medicine and Science, David Geffen UCLA School of Medicine and UCLA Jonsson Comprehensive Cancer Center, Los Angeles, CA 90059, USA
| | - Donghui Zhu
- University of North Texas, Denton, TX 76203, USA
| | - Qiao-Hong Chen
- Department of Chemistry, California State University, Fresno, 2555 E. San Ramon Avenue, M/S SB70, Fresno, CA 93740, USA
| | - Guanglin Chen
- Department of Chemistry, California State University, Fresno, 2555 E. San Ramon Avenue, M/S SB70, Fresno, CA 93740, USA
| | - Jonathan R. Pollack
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jay Vadgama
- Division of Cancer Research and Training, Department of Internal Medicine, Charles Drew University of Medicine and Science, David Geffen UCLA School of Medicine and UCLA Jonsson Comprehensive Cancer Center, Los Angeles, CA 90059, USA
| | - Yong Wu
- Division of Cancer Research and Training, Department of Internal Medicine, Charles Drew University of Medicine and Science, David Geffen UCLA School of Medicine and UCLA Jonsson Comprehensive Cancer Center, Los Angeles, CA 90059, USA
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10
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Clausse V, Tao D, Debnath S, Fang Y, Tagad HD, Wang Y, Sun H, LeClair CA, Mazur SJ, Lane K, Shi ZD, Vasalatiy O, Eells R, Baker LK, Henderson MJ, Webb MR, Shen M, Hall MD, Appella E, Appella DH, Coussens NP. Physiologically relevant orthogonal assays for the discovery of small-molecule modulators of WIP1 phosphatase in high-throughput screens. J Biol Chem 2019; 294:17654-17668. [PMID: 31481464 PMCID: PMC6873202 DOI: 10.1074/jbc.ra119.010201] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/30/2019] [Indexed: 01/07/2023] Open
Abstract
WT P53-Induced Phosphatase 1 (WIP1) is a member of the magnesium-dependent serine/threonine protein phosphatase (PPM) family and is induced by P53 in response to DNA damage. In several human cancers, the WIP1 protein is overexpressed, which is generally associated with a worse prognosis. Although WIP1 is an attractive therapeutic target, no potent, selective, and bioactive small-molecule modulator with favorable pharmacokinetics has been reported. Phosphatase enzymes are among the most challenging targets for small molecules because of the difficulty of achieving both modulator selectivity and bioavailability. Another major obstacle has been the availability of robust and physiologically relevant phosphatase assays that are suitable for high-throughput screening. Here, we describe orthogonal biochemical WIP1 activity assays that utilize phosphopeptides from native WIP1 substrates. We optimized an MS assay to quantify the enzymatically dephosphorylated peptide reaction product in a 384-well format. Additionally, a red-shifted fluorescence assay was optimized in a 1,536-well format to enable real-time WIP1 activity measurements through the detection of the orthogonal reaction product, Pi. We validated these two optimized assays by quantitative high-throughput screening against the National Center for Advancing Translational Sciences (NCATS) Pharmaceutical Collection and used secondary assays to confirm and evaluate inhibitors identified in the primary screen. Five inhibitors were further tested with an orthogonal WIP1 activity assay and surface plasmon resonance binding studies. Our results validate the application of miniaturized physiologically relevant and orthogonal WIP1 activity assays to discover small-molecule modulators from high-throughput screens.
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Affiliation(s)
- Victor Clausse
- Synthetic Bioactive Molecules Section, Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | - Dingyin Tao
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850
| | - Subrata Debnath
- Laboratory of Cell Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Yuhong Fang
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850
| | - Harichandra D Tagad
- Laboratory of Cell Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Yuhong Wang
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850
| | - Hongmao Sun
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850
| | - Christopher A LeClair
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850
| | - Sharlyn J Mazur
- Laboratory of Cell Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Kelly Lane
- Imaging Probe Development Center, NHLBI, National Institutes of Health, Rockville, Maryland 20850
| | - Zhen-Dan Shi
- Imaging Probe Development Center, NHLBI, National Institutes of Health, Rockville, Maryland 20850
| | - Olga Vasalatiy
- Imaging Probe Development Center, NHLBI, National Institutes of Health, Rockville, Maryland 20850
| | - Rebecca Eells
- Reaction Biology Corporation, 1 Great Valley Parkway, Suite 2, Malvern, Pennsylvania 19355
| | - Lynn K Baker
- Reaction Biology Corporation, 1 Great Valley Parkway, Suite 2, Malvern, Pennsylvania 19355
| | - Mark J Henderson
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850
| | - Martin R Webb
- Francis Crick Institute, 1 Midland Road, London NW1 AT, United Kingdom
| | - Min Shen
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850
| | - Matthew D Hall
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850
| | - Ettore Appella
- Laboratory of Cell Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Daniel H Appella
- Synthetic Bioactive Molecules Section, Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | - Nathan P Coussens
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850
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11
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Rodríguez A, Naveja JJ, Torres L, García de Teresa B, Juárez-Figueroa U, Ayala-Zambrano C, Azpeitia E, Mendoza L, Frías S. WIP1 Contributes to the Adaptation of Fanconi Anemia Cells to DNA Damage as Determined by the Regulatory Network of the Fanconi Anemia and Checkpoint Recovery Pathways. Front Genet 2019; 10:411. [PMID: 31130988 PMCID: PMC6509935 DOI: 10.3389/fgene.2019.00411] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 04/15/2019] [Indexed: 02/01/2023] Open
Abstract
DNA damage adaptation (DDA) allows the division of cells with unrepaired DNA damage. DNA repair deficient cells might take advantage of DDA to survive. The Fanconi anemia (FA) pathway repairs DNA interstrand crosslinks (ICLs), and deficiencies in this pathway cause a fraction of breast and ovarian cancers as well as FA, a chromosome instability syndrome characterized by bone marrow failure and cancer predisposition. FA cells are hypersensitive to ICLs; however, DDA might promote their survival. We present the FA-CHKREC Boolean Network Model, which explores how FA cells might use DDA. The model integrates the FA pathway with the G2 checkpoint and the checkpoint recovery (CHKREC) processes. The G2 checkpoint mediates cell-cycle arrest (CCA) and the CHKREC activates cell-cycle progression (CCP) after resolution of DNA damage. Analysis of the FA-CHKREC network indicates that CHKREC drives DDA in FA cells, ignoring the presence of unrepaired DNA damage and allowing their division. Experimental inhibition of WIP1, a CHKREC component, in FA lymphoblast and cancer cell lines prevented division of FA cells, in agreement with the prediction of the model.
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Affiliation(s)
- Alfredo Rodríguez
- Laboratorio de Citogenética, Departamento de Investigación en Genética Humana, Instituto Nacional de Pediatría, Mexico City, Mexico
| | - J Jesús Naveja
- PECEM, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Leda Torres
- Laboratorio de Citogenética, Departamento de Investigación en Genética Humana, Instituto Nacional de Pediatría, Mexico City, Mexico
| | - Benilde García de Teresa
- Laboratorio de Citogenética, Departamento de Investigación en Genética Humana, Instituto Nacional de Pediatría, Mexico City, Mexico
| | - Ulises Juárez-Figueroa
- Laboratorio de Citogenética, Departamento de Investigación en Genética Humana, Instituto Nacional de Pediatría, Mexico City, Mexico.,Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Cecilia Ayala-Zambrano
- Laboratorio de Citogenética, Departamento de Investigación en Genética Humana, Instituto Nacional de Pediatría, Mexico City, Mexico
| | - Eugenio Azpeitia
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Luis Mendoza
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Sara Frías
- Laboratorio de Citogenética, Departamento de Investigación en Genética Humana, Instituto Nacional de Pediatría, Mexico City, Mexico.,Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
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12
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Tagad HD, Debnath S, Clausse V, Saha M, Mazur SJ, Appella E, Appella DH. Chemical Features Important for Activity in a Class of Inhibitors Targeting the Wip1 Flap Subdomain. ChemMedChem 2018; 13:894-901. [PMID: 29476592 PMCID: PMC8022280 DOI: 10.1002/cmdc.201700779] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Indexed: 12/12/2022]
Abstract
The wild-type p53 induced phosphatase 1, Wip1 (PP2Cδ), is a protein phosphatase 2C (PP2C) family serine/threonine phosphatase that negatively regulates the function of the tumor suppressor p53 and several of its positive regulators such as ATM, Chk1, Chk2, Mdm2, and p38 MAPK. Wip1 dephosphorylates and inactivates its protein targets, which are critical for cellular stress responses. Additionally, Wip1 is frequently amplified and overexpressed in several human cancer types. Because of its negative role in regulating the function of tumor suppressor proteins, Wip1 has been identified as a potential therapeutic target in various types of cancers. Based on a recently reported Wip1 inhibitor (G-1), we performed an extensive structure-activity relationship (SAR) analysis. This led us to interesting findings in SAR trends and to the discovery of new chemical analogues with good specificity and bioavailability.
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Affiliation(s)
- Harichandra D Tagad
- Laboratory of Cell Biology, National Cancer Institute, US National Institutes of Health, Bethesda, MD, 20892, USA
| | - Subrata Debnath
- Laboratory of Cell Biology, National Cancer Institute, US National Institutes of Health, Bethesda, MD, 20892, USA
| | - Victor Clausse
- Synthetic Bioactive Molecules Section, LBC, NIDDK, US National Institutes of Health, 8 Center Drive, Room 404, Bethesda, MD, 20892, USA
| | - Mrinmoy Saha
- Synthetic Bioactive Molecules Section, LBC, NIDDK, US National Institutes of Health, 8 Center Drive, Room 404, Bethesda, MD, 20892, USA
| | - Sharlyn J Mazur
- Laboratory of Cell Biology, National Cancer Institute, US National Institutes of Health, Bethesda, MD, 20892, USA
| | - Ettore Appella
- Laboratory of Cell Biology, National Cancer Institute, US National Institutes of Health, Bethesda, MD, 20892, USA
| | - Daniel H Appella
- Synthetic Bioactive Molecules Section, LBC, NIDDK, US National Institutes of Health, 8 Center Drive, Room 404, Bethesda, MD, 20892, USA
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13
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Demirkıran G, Kalaycı Demir G, Güzeliş C. Revealing determinants of two-phase dynamics of P53 network under gamma irradiation based on a reduced 2D relaxation oscillator model. IET Syst Biol 2018; 12:26-38. [PMID: 29337287 PMCID: PMC8687238 DOI: 10.1049/iet-syb.2017.0041] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 10/17/2017] [Accepted: 10/25/2017] [Indexed: 01/03/2023] Open
Abstract
This study proposes a two-dimensional (2D) oscillator model of p53 network, which is derived via reducing the multidimensional two-phase dynamics model into a model of ataxia telangiectasia mutated (ATM) and Wip1 variables, and studies the impact of p53-regulators on cell fate decision. First, the authors identify a 6D core oscillator module, then reduce this module into a 2D oscillator model while preserving the qualitative behaviours. The introduced 2D model is shown to be an excitable relaxation oscillator. This oscillator provides a mechanism that leads diverse modes underpinning cell fate, each corresponding to a cell state. To investigate the effects of p53 inhibitors and the intrinsic time delay of Wip1 on the characteristics of oscillations, they introduce also a delay differential equation version of the 2D oscillator. They observe that the suppression of p53 inhibitors decreases the amplitudes of p53 oscillation, though the suppression increases the sustained level of p53. They identify Wip1 and P53DINP1 as possible targets for cancer therapies considering their impact on the oscillator, supported by biological findings. They model some mutations as critical changes of the phase space characteristics. Possible cancer therapeutic strategies are then proposed for preventing these mutations' effects using the phase space approach.
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Affiliation(s)
- Gökhan Demirkıran
- The Graduate School of Natural and Applied Sciences, Dokuz Eylül University, Buca, İzmir 35160, Turkey.
| | - Güleser Kalaycı Demir
- Department of Electrical and Electronics Engineering, Dokuz Eylül University, Buca, İzmir 35160, Turkey
| | - Cüneyt Güzeliş
- Department of Electrical-Electronics Engineering, Yaşar University, Bornova, İzmir 35100, Turkey
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14
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Pecháčková S, Burdová K, Macurek L. WIP1 phosphatase as pharmacological target in cancer therapy. J Mol Med (Berl) 2017; 95:589-599. [PMID: 28439615 PMCID: PMC5442293 DOI: 10.1007/s00109-017-1536-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 04/13/2017] [Accepted: 04/19/2017] [Indexed: 12/31/2022]
Abstract
DNA damage response (DDR) pathway protects cells from genome instability and prevents cancer development. Tumor suppressor p53 is a key molecule that interconnects DDR, cell cycle checkpoints, and cell fate decisions in the presence of genotoxic stress. Inactivating mutations in TP53 and other genes implicated in DDR potentiate cancer development and also influence the sensitivity of cancer cells to treatment. Protein phosphatase 2C delta (referred to as WIP1) is a negative regulator of DDR and has been proposed as potential pharmaceutical target. Until recently, exploitation of WIP1 inhibition for suppression of cancer cell growth was compromised by the lack of selective small-molecule inhibitors effective at cellular and organismal levels. Here, we review recent advances in development of WIP1 inhibitors and discuss their potential use in cancer treatment.
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Affiliation(s)
- Soňa Pecháčková
- Department of Cancer Cell Biology, Institute of Molecular Genetics of the ASCR, CZ-14220, Prague, Czech Republic
| | - Kamila Burdová
- Department of Cancer Cell Biology, Institute of Molecular Genetics of the ASCR, CZ-14220, Prague, Czech Republic
| | - Libor Macurek
- Department of Cancer Cell Biology, Institute of Molecular Genetics of the ASCR, CZ-14220, Prague, Czech Republic.
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15
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Oghabi Bakhshaiesh T, Majidzadeh-A K, Esmaeili R. Wip1: A candidate phosphatase for cancer diagnosis and treatment. DNA Repair (Amst) 2017; 54:63-66. [PMID: 28385459 DOI: 10.1016/j.dnarep.2017.03.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 03/17/2017] [Accepted: 03/18/2017] [Indexed: 12/28/2022]
Abstract
The critical regulatory mechanisms in numerous cellular pathways including cell survival and DNA damage response mostly depend on phosphorylation and dephosphorylation of proteins. The serine/threonine phosphatase wild-type p53-induced phosphatase 1 (Wip1) is a growth-promoting phosphatase and its numerous downstream targets are important tumor suppressors. Here, we review the Wip1 activity and its relevance to cancer as an oncoprotein. Consecutive investigations about Wip1 and its relation to cancer is critical, as these studies ultimately contribute to the etiology of cancer. A number of innovative studies have recently investigated the importance of Wip1 as a new candidate for cancer diagnosis and prognosis. Accordingly, we discuss the present challenges of using Wip1 as a target for cancer treatment.
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Affiliation(s)
| | - Keivan Majidzadeh-A
- Genetics Department, Breast Cancer Research Center, Motamed Cancer Institute, ACECR, Tehran, Iran
| | - Rezvan Esmaeili
- Genetics Department, Breast Cancer Research Center, Motamed Cancer Institute, ACECR, Tehran, Iran.
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16
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Wamsley JJ, Issaeva N, An H, Lu X, Donehower LA, Yarbrough WG. LZAP is a novel Wip1 binding partner and positive regulator of its phosphatase activity in vitro. Cell Cycle 2016; 16:213-223. [PMID: 28027003 DOI: 10.1080/15384101.2016.1261767] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The phosphatase Wip1 attenuates the DNA damage response (DDR) by removing phosphorylation marks from a number of DDR proteins (p53, MDM2, Chk1/2, p38). Wip1 also dephosphorylates and inactivates RelA. Notably, LZAP, a putative tumor suppressor, has been linked to dephosphorylation of several of these substrates, including RelA, p38, Chk1, and Chk2. LZAP has no known catalytic activity or functional motifs, suggesting that it exerts its effects through interaction with other proteins. Here we show that LZAP binds Wip1 and stimulates its phosphatase activity. LZAP had been previously shown to bind many Wip1 substrates (RelA, p38, Chk1/2), and our results show that LZAP also binds the previously identified Wip1 substrate, MDM2. This work identifies 2 novel Wip1 substrates, ERK1 and HuR, and demonstrates that HuR is a binding partner of LZAP. Pleasingly, LZAP potentiated Wip1 catalytic activity toward each substrate tested, regardless of whether full-length substrates or phosphopeptides were utilized. Since this effect was observed on ERK1, which does not bind LZAP, as well as for each of 7 peptides tested, we hypothesize that LZAP binding to the substrate is not required for this effect and that LZAP directly binds Wip1 to augment its phosphatase activity.
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Affiliation(s)
- J Jacob Wamsley
- a Department of Surgery, Division of Otolaryngology , Yale University , New Haven , CT , USA
| | - Natalia Issaeva
- a Department of Surgery, Division of Otolaryngology , Yale University , New Haven , CT , USA.,b Yale Cancer Center, Yale University , New Haven , CT , USA
| | - Hanbing An
- c Department of Surgery , Vanderbilt University , Nashville , TN , USA
| | - Xinyuan Lu
- d Department of Medicine , University of California San Francisco , San Francisco , CA , USA
| | - Lawrence A Donehower
- e Department of Molecular Virology and Microbiology , Baylor College of Medicine , Houston , TX , USA
| | - Wendell G Yarbrough
- a Department of Surgery, Division of Otolaryngology , Yale University , New Haven , CT , USA.,b Yale Cancer Center, Yale University , New Haven , CT , USA.,f Department of Pathology , Yale University , New Haven , CT , USA
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17
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Chen Z, Wang L, Yao D, Yang T, Cao WM, Dou J, Pang JC, Guan S, Zhang H, Yu Y, Zhao Y, Wang Y, Xu X, Shi Y, Patel R, Zhang H, Vasudevan SA, Liu S, Yang J, Nuchtern JG. Wip1 inhibitor GSK2830371 inhibits neuroblastoma growth by inducing Chk2/p53-mediated apoptosis. Sci Rep 2016; 6:38011. [PMID: 27991505 PMCID: PMC5171816 DOI: 10.1038/srep38011] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 11/03/2016] [Indexed: 02/06/2023] Open
Abstract
Neuroblastoma (NB) is the most common extracranial tumor in children. Unlike in most adult tumors, tumor suppressor protein 53 (p53) mutations occur with a relatively low frequency in NB and the downstream function of p53 is intact in NB cell lines. Wip1 is a negative regulator of p53 and hindrance of Wip1 activity by novel inhibitor GSK2830371 is a potential strategy to activate p53’s tumor suppressing function in NB. Yet, the in vivo efficacy and the possible mechanisms of GSK2830371 in NB have not yet been elucidated. Here we report that novel Wip1 inhibitor GSK2830371 induced Chk2/p53-mediated apoptosis in NB cells in a p53-dependent manner. In addition, GSK2830371 suppressed the colony-formation potential of p53 wild-type NB cell lines. Furthermore, GSK2830371 enhanced doxorubicin- (Dox) and etoposide- (VP-16) induced cytotoxicity in a subset of NB cell lines, including the chemoresistant LA-N-6 cell line. More importantly, GSK2830371 significantly inhibited tumor growth in an orthotopic xenograft NB mouse model by inducing Chk2/p53-mediated apoptosis in vivo. Taken together, this study suggests that GSK2830371 induces Chk2/p53-mediated apoptosis both in vitro and in vivo in a p53 dependent manner.
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Affiliation(s)
- Zhenghu Chen
- Department of Ophthalmology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, P. R. China.,Texas Children's Cancer Center, Department of Pediatrics, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Long Wang
- Department of Pathology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA.,Department of Acupuncture, First Affiliated Hospital, Heilongjiang University of Chinese Medicine, Harbin, Heilongjiang 150040, China
| | - Dayong Yao
- Department of Pathology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA.,Department of Urology, First Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang 150001, China
| | - Tianshu Yang
- Department of Ophthalmology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, P. R. China
| | - Wen-Ming Cao
- Department of Pathology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA.,Department of Medical Oncology, Zhejiang Cancer Hospital, Hangzhou, Zhejiang 310022, China
| | - Jun Dou
- Department of Pathology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA.,Xinjiang Key Laboratory of Plant Resources and Natural Products Chemistry, Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Urumqi, Xinjiang 830011, China
| | - Jonathan C Pang
- Texas Children's Cancer Center, Department of Pediatrics, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Shan Guan
- Texas Children's Cancer Center, Department of Pediatrics, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Huiyuan Zhang
- Texas Children's Cancer Center, Department of Pediatrics, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Yang Yu
- Texas Children's Cancer Center, Department of Pediatrics, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Yanling Zhao
- Texas Children's Cancer Center, Department of Pediatrics, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Yongfeng Wang
- Texas Children's Cancer Center, Department of Pediatrics, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Xin Xu
- Texas Children's Cancer Center, Department of Pediatrics, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Yan Shi
- Division of Pediatric Surgery, Michael E. DeBakey Department of Pediatric Surgery, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Roma Patel
- Division of Pediatric Surgery, Michael E. DeBakey Department of Pediatric Surgery, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Hong Zhang
- Department of Pathology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Sanjeev A Vasudevan
- Division of Pediatric Surgery, Michael E. DeBakey Department of Pediatric Surgery, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Shangfeng Liu
- Department of Ophthalmology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, P. R. China.,Department of Stomatology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Jianhua Yang
- Texas Children's Cancer Center, Department of Pediatrics, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Jed G Nuchtern
- Texas Children's Cancer Center, Department of Pediatrics, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas 77030, USA.,Division of Pediatric Surgery, Michael E. DeBakey Department of Pediatric Surgery, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas 77030, USA
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18
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Hat B, Kochańczyk M, Bogdał MN, Lipniacki T. Feedbacks, Bifurcations, and Cell Fate Decision-Making in the p53 System. PLoS Comput Biol 2016; 12:e1004787. [PMID: 26928575 PMCID: PMC4771203 DOI: 10.1371/journal.pcbi.1004787] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 02/03/2016] [Indexed: 01/07/2023] Open
Abstract
The p53 transcription factor is a regulator of key cellular processes including DNA repair, cell cycle arrest, and apoptosis. In this theoretical study, we investigate how the complex circuitry of the p53 network allows for stochastic yet unambiguous cell fate decision-making. The proposed Markov chain model consists of the regulatory core and two subordinated bistable modules responsible for cell cycle arrest and apoptosis. The regulatory core is controlled by two negative feedback loops (regulated by Mdm2 and Wip1) responsible for oscillations, and two antagonistic positive feedback loops (regulated by phosphatases Wip1 and PTEN) responsible for bistability. By means of bifurcation analysis of the deterministic approximation we capture the recurrent solutions (i.e., steady states and limit cycles) that delineate temporal responses of the stochastic system. Direct switching from the limit-cycle oscillations to the “apoptotic” steady state is enabled by the existence of a subcritical Neimark—Sacker bifurcation in which the limit cycle loses its stability by merging with an unstable invariant torus. Our analysis provides an explanation why cancer cell lines known to have vastly diverse expression levels of Wip1 and PTEN exhibit a broad spectrum of responses to DNA damage: from a fast transition to a high level of p53 killer (a p53 phosphoform which promotes commitment to apoptosis) in cells characterized by high PTEN and low Wip1 levels to long-lasting p53 level oscillations in cells having PTEN promoter methylated (as in, e.g., MCF-7 cell line). Cancers are diseases of signaling networks. Transcription factor p53 is a pivotal node of a network that integrates a variety of stress signals and governs critical processes of DNA repair, cell cycle arrest, and apoptosis. Somewhat paradoxically, despite the fact that carcinogenesis is prevalently caused by p53 network malfunction, most of our knowledge about p53 signaling is based on cancer or immortalized cell lines. In this paper, we construct a mathematical model of intact p53 network to understand dynamics of non-cancerous cells and then dynamics of cancerous cells by introducing perturbations to the regulatory system. Cell fate decisions are enabled by the presence of interlinked feedback loops which give rise to a rich repertoire of behaviors. We explain and analyze by means of numerical simulations how the dynamical structure of the regulatory system allows for generating unambiguous single-cell fate decisions, also in the case when the cell population splits into an apoptotic and a surviving subpopulation. Perturbation analysis provides an explanation why cancer cell lines known to have vastly diverse expression levels of p53 regulators can exhibit a broad spectrum of responses to DNA damage.
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Affiliation(s)
- Beata Hat
- Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland
| | - Marek Kochańczyk
- Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland
| | - Marta N. Bogdał
- Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland
| | - Tomasz Lipniacki
- Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland
- Department of Statistics, Rice University, Houston, Texas, United States of America
- * E-mail:
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19
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Jeong HC, Gil NY, Lee HS, Cho SJ, Kim K, Chun KH, Cho H, Cha HJ. Timely Degradation of Wip1 Phosphatase by APC/C Activator Protein Cdh1 is Necessary for Normal Mitotic Progression. J Cell Biochem 2015; 116:1602-12. [DOI: 10.1002/jcb.25114] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 01/23/2015] [Indexed: 12/16/2022]
Affiliation(s)
- Ho-Chang Jeong
- College of Natural Sciences; Department of Life Sciences; Sogang University; Seoul Korea
| | - Na-Yeon Gil
- College of Natural Sciences; Department of Life Sciences; Sogang University; Seoul Korea
| | - Ho-Soo Lee
- Department of Biochemistry; Ajou University School of Medicine; Suwon Korea
- Genomic Instability Research Center; Ajou University School of Medicine; Suwon Korea
| | - Seung-Ju Cho
- College of Natural Sciences; Department of Life Sciences; Sogang University; Seoul Korea
| | - Kyungtae Kim
- National Cancer Center; Goyang-si; Gyeonggi-do Korea
| | - Kwang-Hoon Chun
- Gachon Institute of Pharmaceutical Sciences; College of Pharmacy; Gachon University; Incheon Korea
| | - Hyeseong Cho
- Department of Biochemistry; Ajou University School of Medicine; Suwon Korea
- Genomic Instability Research Center; Ajou University School of Medicine; Suwon Korea
| | - Hyuk-Jin Cha
- College of Natural Sciences; Department of Life Sciences; Sogang University; Seoul Korea
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20
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Wang H, Zhang X, Teng L, Legerski RJ. DNA damage checkpoint recovery and cancer development. Exp Cell Res 2015; 334:350-8. [PMID: 25842165 DOI: 10.1016/j.yexcr.2015.03.011] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 03/12/2015] [Accepted: 03/14/2015] [Indexed: 12/21/2022]
Abstract
Cell cycle checkpoints were initially presumed to function as a regulator of cell cycle machinery in response to different genotoxic stresses, and later found to play an important role in the process of tumorigenesis by acting as a guard against DNA over-replication. As a counterpart of checkpoint activation, the checkpoint recovery machinery is working in opposition, aiming to reverse the checkpoint activation and resume the normal cell cycle. The DNA damage response (DDR) and oncogene induced senescence (OIS) are frequently found in precancerous lesions, and believed to constitute a barrier to tumorigenesis, however, the DDR and OIS have been observed to be diminished in advanced cancers of most tissue origins. These findings suggest that when progressing from pre-neoplastic lesions to cancer, DNA damage checkpoint barriers are overridden. How the DDR checkpoint is bypassed in this process remains largely unknown. Activated cytokine and growth factor-signaling pathways were very recently shown to suppress the DDR and to promote uncontrolled cell proliferation in the context of oncovirus infection. In recent decades, data from cell line and tumor models showed that a group of checkpoint recovery proteins function in promoting tumor progression; data from patient samples also showed overexpression of checkpoint recovery proteins in human cancer tissues and a correlation with patients׳ poor prognosis. In this review, the known cell cycle checkpoint recovery proteins and their roles in DNA damage checkpoint recovery are reviewed, as well as their implications in cancer development. This review also provides insight into the mechanism by which the DDR suppresses oncogene-driven tumorigenesis and tumor progression.
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Affiliation(s)
- Haiyong Wang
- First affiliated hospital, Zhejiang University, School of medicine, Cancer Center, 79 Qingchun Road, Hangzhou 310003, China
| | - Xiaoshan Zhang
- Department of Genetics, University of Texas M.D. Anderson Cancer Center, Department of Genetics Unit 1010, 1515 Holcombe Blvd. Houston, TX 77030 USA
| | - Lisong Teng
- First affiliated hospital, Zhejiang University, School of medicine, Cancer Center, 79 Qingchun Road, Hangzhou 310003, China.
| | - Randy J Legerski
- Department of Genetics, University of Texas M.D. Anderson Cancer Center, Department of Genetics Unit 1010, 1515 Holcombe Blvd. Houston, TX 77030 USA.
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21
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Richter M, Dayaram T, Gilmartin AG, Ganji G, Pemmasani SK, Van Der Key H, Shohet JM, Donehower LA, Kumar R. WIP1 phosphatase as a potential therapeutic target in neuroblastoma. PLoS One 2015; 10:e0115635. [PMID: 25658463 PMCID: PMC4319922 DOI: 10.1371/journal.pone.0115635] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 11/25/2014] [Indexed: 12/15/2022] Open
Abstract
The wild-type p53-induced phosphatase 1 (WIP1) is a serine/threonine phosphatase that negatively regulates multiple proteins involved in DNA damage response including p53, CHK2, Histone H2AX, and ATM, and it has been shown to be overexpressed or amplified in human cancers including breast and ovarian cancers. We examined WIP1 mRNA levels across multiple tumor types and found the highest levels in breast cancer, leukemia, medulloblastoma and neuroblastoma. Neuroblastoma is an exclusively TP53 wild type tumor at diagnosis and inhibition of p53 is required for tumorigenesis. Neuroblastomas in particular have previously been shown to have 17q amplification, harboring the WIP1 (PPM1D) gene and associated with poor clinical outcome. We therefore sought to determine whether inhibiting WIP1 with a selective antagonist, GSK2830371, can attenuate neuroblastoma cell growth through reactivation of p53 mediated tumor suppression. Neuroblastoma cell lines with wild-type TP53 alleles were highly sensitive to GSK2830371 treatment, while cell lines with mutant TP53 were resistant to GSK2830371. The majority of tested neuroblastoma cell lines with copy number gains of the PPM1D locus were also TP53 wild-type and sensitive to GSK2830371A; in contrast cell lines with no copy gain of PPM1D were mixed in their sensitivity to WIP1 inhibition, with the primary determinant being TP53 mutational status. Since WIP1 is involved in the cellular response to DNA damage and drugs used in neuroblastoma treatment induce apoptosis through DNA damage, we sought to determine whether GSK2830371 could act synergistically with standard of care chemotherapeutics. Treatment of wild-type TP53 neuroblastoma cell lines with both GSK2830371 and either doxorubicin or carboplatin resulted in enhanced cell death, mediated through caspase 3/7 induction, as compared to either agent alone. Our data suggests that WIP1 inhibition represents a novel therapeutic approach to neuroblastoma that could be integrated with current chemotherapeutic approaches.
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Affiliation(s)
- Mark Richter
- Oncology R&D, GlaxoSmithKline, 1250 S. Collegeville Road, Collegeville, Pennsylvania, United States of America
| | - Tajhal Dayaram
- Department of Molecular Virology and Microbiology and Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Aidan G. Gilmartin
- Oncology R&D, GlaxoSmithKline, 1250 S. Collegeville Road, Collegeville, Pennsylvania, United States of America
| | - Gopinath Ganji
- Oncology R&D, GlaxoSmithKline, 1250 S. Collegeville Road, Collegeville, Pennsylvania, United States of America
| | | | - Harjeet Van Der Key
- Platform Technology & Science, GlaxoSmithKline, 1250 S. Collegeville Road, Collegeville, Pennsylvania, United States of America
| | - Jason M. Shohet
- Texas Children’s Cancer Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Lawrence A. Donehower
- Department of Molecular Virology and Microbiology and Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail: (LAD); (RK)
| | - Rakesh Kumar
- Oncology R&D, GlaxoSmithKline, 1250 S. Collegeville Road, Collegeville, Pennsylvania, United States of America
- * E-mail: (LAD); (RK)
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22
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WIP1 regulates the proliferation and invasion of nasopharyngeal carcinoma in vitro. Tumour Biol 2014; 35:7651-7. [PMID: 24801909 DOI: 10.1007/s13277-014-2034-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 04/28/2014] [Indexed: 01/07/2023] Open
Abstract
Wild-type p53-induced phosphatase (WIP1) is overexpressed and functionally altered in multiple human malignancies. The present study investigated its abnormal expression and dysfunctions in nasopharyngeal carcinoma (NPC) in vitro. Here, analysis of WIP1 mRNA and protein in human NPC tissues revealed that both WIP1 messenger RNA (mRNA) and protein were elevated and were correlated with NPC clinical stage and metastasis in patients. In vitro experiments further showed that WIP1 inhibition led to a decrease in the proliferative ability of NPC CNE-2 and 5-8F cells accompanied by cell cycle arrest and increased apoptosis. In addition, WIP1 knockdown inhibited the invasiveness of CNE-2 and 5-8F cells and was associated with the down-regulation of the expression of matrix metallopeptidase 9 (MMP-9) mRNA and protein. Taken together, our data demonstrate that WIP1 regulates the proliferation and invasiveness of NPC cells in vitro, and this may be correlated with its modulation of MMP-9 expression, cell cycle progression and apoptosis. WIP1 functioned as a potential therapeutic target in NPC management.
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23
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Off-target response of a Wip1 chemical inhibitor in skin keratinocytes. J Dermatol Sci 2014; 73:125-34. [DOI: 10.1016/j.jdermsci.2013.09.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 07/15/2013] [Accepted: 09/05/2013] [Indexed: 01/05/2023]
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Liu MT, Nagre NN, Ryan K. Structurally diverse low molecular weight activators of the mammalian pre-mRNA 3' cleavage reaction. Bioorg Med Chem 2014; 22:834-41. [PMID: 24373842 PMCID: PMC4018835 DOI: 10.1016/j.bmc.2013.12.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 11/23/2013] [Accepted: 12/03/2013] [Indexed: 11/15/2022]
Abstract
The 3' end formation of mammalian pre-mRNA contributes to gene expression regulation by setting the downstream boundary of the 3' untranslated region, which in many genes carries regulatory sequences. A large number of protein cleavage factors participate in this pre-mRNA processing step, but chemical tools to manipulate this process are lacking. Guided by a hypothesis that a PPM1 family phosphatase negatively regulates the 3' cleavage reaction, we have found a variety of new small molecule activators of the in vitro reconstituted pre-mRNA 3' cleavage reaction. New activators include a cyclic peptide PPM1D inhibitor, a dipeptide with modifications common to histone tails, abscisic acid and an improved l-arginine β-naphthylamide analog. The minimal concentration required for in vitro cleavage has been improved from 200μM to the 200nM-100μM range. These compounds provide unexpected leads in the search for small molecule tools able to affect pre-mRNA 3' end formation.
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Affiliation(s)
- Min Ting Liu
- Department of Chemistry, The City College of New York, The City University of New York, New York, NY 10031, USA
| | - Nagaraja N Nagre
- Department of Chemistry, The City College of New York, The City University of New York, New York, NY 10031, USA
| | - Kevin Ryan
- Department of Chemistry, The City College of New York, The City University of New York, New York, NY 10031, USA.
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25
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Zhang M, Yogesha SD, Mayfield JE, Gill GN, Zhang Y. Viewing serine/threonine protein phosphatases through the eyes of drug designers. FEBS J 2013; 280:4739-60. [PMID: 23937612 DOI: 10.1111/febs.12481] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 07/03/2013] [Accepted: 08/02/2013] [Indexed: 01/04/2023]
Abstract
Protein phosphatases, as the counterpart to protein kinases, are essential for homeostatic balance of cell signaling. Small chemical compounds that modulate the specific activity of phosphatases can be powerful tools to elucidate the biological functions of these enzymes. More importantly, many phosphatases are central players in the development of pathological pathways where inactivation can reverse or delay the onset of human diseases. Therefore, potent inhibitors for such phosphatases can be of great therapeutic benefit. In contrast to the seemingly identical enzymatic mechanism and structural characterization of eukaryotic protein kinases, protein phosphatases evolved from diverse ancestors, resulting in different domain architectures, reaction mechanisms and active site properties. In this review, we discuss for each family of serine/threonine protein phosphatases their involvement in biological processes and corresponding strategies for small chemical intervention. Recent advances in modern drug discovery technologies have markedly facilitated the identification of selective inhibitors for some members of the phosphatase family. Furthermore, the rapid growth in knowledge about structure-activity relationships related to possible new drug targets has aided the discovery of natural product inhibitors for the phosphatase family. This review summarizes the current state of investigation of the small molecules that regulate the function of serine/threonine phosphatases, the challenges presented and also strategies to overcome these obstacles.
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Affiliation(s)
- Mengmeng Zhang
- Department of Chemistry and Biochemistry, University of Texas at Austin, TX, USA
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26
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Dayaram T, Lemoine FJ, Donehower LA, Marriott SJ. Activation of WIP1 phosphatase by HTLV-1 Tax mitigates the cellular response to DNA damage. PLoS One 2013; 8:e55989. [PMID: 23405243 PMCID: PMC3566092 DOI: 10.1371/journal.pone.0055989] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 01/08/2013] [Indexed: 12/21/2022] Open
Abstract
Genomic instability stemming from dysregulation of cell cycle checkpoints and DNA damage response (DDR) is a common feature of many cancers. The cancer adult T cell leukemia (ATL) can occur in individuals infected with human T cell leukemia virus type 1 (HTLV-1), and ATL cells contain extensive chromosomal abnormalities, suggesting that they have defects in the recognition or repair of DNA damage. Since Tax is the transforming protein encoded by HTLV-1, we asked whether Tax can affect cell cycle checkpoints and the DDR. Using a combination of flow cytometry and DNA repair assays we showed that Tax-expressing cells exit G1 phase and initiate DNA replication prematurely following damage. Reduced phosphorylation of H2AX (γH2AX) and RPA2, phosphoproteins that are essential to properly initiate the DDR, was also observed in Tax-expressing cells. To determine the cause of decreased DDR protein phosphorylation in Tax-expressing cells, we examined the cellular phosphatase, WIP1, which is known to dephosphorylate γH2AX. We found that Tax can interact with Wip1 in vivo and in vitro, and that Tax-expressing cells display elevated levels of Wip1 mRNA. In vitro phosphatase assays showed that Tax can enhance Wip1 activity on a γH2AX peptide target by 2-fold. Thus, loss of γH2AX in vivo could be due, in part, to increased expression and activity of WIP1 in the presence of Tax. siRNA knockdown of WIP1 in Tax-expressing cells rescued γH2AX in response to damage, confirming the role of WIP1 in the DDR. These studies demonstrate that Tax can disengage the G1/S checkpoint by enhancing WIP1 activity, resulting in reduced DDR. Premature G1 exit of Tax-expressing cells in the presence of DNA lesions creates an environment that tolerates incorporation of random mutations into the host genome.
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Affiliation(s)
- Tajhal Dayaram
- Interdepartmental Program in Cell and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Francene J. Lemoine
- Department of Biological Sciences, Northwestern State University of Louisiana, Natchitoches, Louisiana, United States of America
| | - Lawrence A. Donehower
- Interdepartmental Program in Cell and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Susan J. Marriott
- Interdepartmental Program in Cell and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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Ali AY, Farrand L, Kim JY, Byun S, Suh JY, Lee HJ, Tsang BK. Molecular determinants of ovarian cancer chemoresistance: new insights into an old conundrum. Ann N Y Acad Sci 2013; 1271:58-67. [PMID: 23050965 PMCID: PMC3499654 DOI: 10.1111/j.1749-6632.2012.06734.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Ovarian cancer is the most lethal gynecological malignancy. Cisplatin and its derivatives are first-line chemotherapeutics, and their resistance is a major hurdle in successful ovarian cancer treatment. Understanding the molecular dysregulation underlying chemoresistance is important for enhancing therapeutic outcome. Here, we review two established pathways in cancer chemoresistance. p53 is a major tumor suppressor regulating proliferation and apoptosis, and its mutation is a frequent event in human malignancies. The PI3K/Akt axis is a key oncogenic pathway regulating survival and tumorigenesis by controlling several tumor suppressors, including p53. The interplay between these pathways is well established, although the oncogenic phosphatase PPM1D adds a new layer to this intricate relationship and provides new insights into the processes determining cell fate. Inhibition of the PI3K/Akt pathway by functional food compounds as an adjunct to chemotherapeutics may tip the balance in favor of apoptosis rather than survival, enhancing therapeutic efficacy, and reducing side effects.
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Affiliation(s)
- Ahmed Y Ali
- Department of Cellular Medicine, University of Ottawa, Ottawa, Ontario, Canada
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28
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Doucette TA, Yang Y, Pedone C, Kim JYH, Dubuc A, Northcott PD, Taylor MD, Fults DW, Rao G. WIP1 enhances tumor formation in a sonic hedgehog-dependent model of medulloblastoma. Neurosurgery 2012; 70:1003-10; discussion 1010. [PMID: 22037313 DOI: 10.1227/neu.0b013e31823e5332] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND A significant number of medulloblastomas (MBs) originate from abnormal activation of the sonic hedgehog/patched (SHH/PTC) signaling pathway. Although p53 deficiency enhances tumor formation in mice, inactivation of the p53 gene is seen in a minority of MBs. Wild-type p53-induced phosphatase 1 (WIP1) downregulates p53 expression and has been shown to be overexpressed in MBs. OBJECTIVE We tested the hypothesis that overexpression of WIP1 enhances tumor formation in an SHH-dependent model of MB. METHODS We used the RCAS/Ntv-a system to study the effect of WIP1 in vitro and in vivo. We transfected A375-TVA cells with RCAS-WIP1 and then exposed these cells to cisplatin to determine the effect on p53 expression. We modeled ectopic WIP1 expression independently and in combination with SHH in the cerebella of newborn mice to assess the effect on tumor formation. Mice were observed for 12 weeks or until neurological symptoms developed. The brains were examined for tumor formation. RESULTS A375-TVA cells infected with RCAS-WIP1 demonstrated reduced p53 expression after exposure to cisplatin compared with controls. We detected tumors in 12 of 35 mice (34%) injected with RCAS-WIP1 and RCAS-SHH. Tumors were detected in 3 of 40 mice (8%) injected with RCAS-SHH alone. The difference in tumor formation rates was significant (χ(2) test, P = < .01). Tumors did not form in mice injected with RCAS-WIP1 alone. CONCLUSION We show that ectopic expression of WIP1 cooperates with SHH to enhance formation of MB, although it is insufficient to induce tumors independently. Our results verify the role of WIP1 in MB formation and provide a crucial link to the inactivation of p53 in MBs.
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Affiliation(s)
- Tiffany A Doucette
- Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
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29
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van der Weyden L, Adams DJ. Using mice to unveil the genetics of cancer resistance. Biochim Biophys Acta Rev Cancer 2012; 1826:312-30. [PMID: 22613679 DOI: 10.1016/j.bbcan.2012.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 05/10/2012] [Accepted: 05/13/2012] [Indexed: 11/28/2022]
Abstract
In the UK, four in ten people will develop some form of cancer during their lifetime, with an individual's relative risk depending on many factors, including age, lifestyle and genetic make-up. Much research has gone into identifying the genes that are mutated in tumorigenesis with the overwhelming majority of genetically-modified (GM) mice in cancer research showing accelerated tumorigenesis or recapitulating key aspects of the tumorigenic process. Yet if six out of ten people will not develop some form of cancer during their lifetime, together with the fact that some cancer patients experience spontaneous regression/remission, it suggests there are ways of 'resisting' cancer. Indeed, there are wildtype, spontaneously-arising mutants and GM mice that show some form of 'resistance' to cancer. Identification of mice with increased resistance to cancer is a novel aspect of cancer research that is important in terms of providing both chemopreventative and therapeutic options. In this review we describe the different mouse lines that display a 'cancer resistance' phenotype and discuss the molecular basis of their resistance.
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Affiliation(s)
- Louise van der Weyden
- Experimental Cancer Genetics, Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK.
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30
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Wip1 promotes RUNX2-dependent apoptosis in p53-negative tumors and protects normal tissues during treatment with anticancer agents. Proc Natl Acad Sci U S A 2011; 109:E68-75. [PMID: 22065775 DOI: 10.1073/pnas.1107017108] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The inactivation of the p53 tumor suppressor pathway in many cancers often increases their resistance to anticancer therapy. Here we show that a previously proposed strategy directed to Wip1 inhibition could be ineffective in tumors lacking p53. On the contrary, Wip1 overexpression sensitized these tumors to chemotherapeutic agents. This effect was mediated through interaction between Wip1 and RUNX2 that resulted, in response to anticancer treatment, in RUNX2-dependent transcriptional induction of the proapoptotic Bax protein. The potentiating effects of Wip1 overexpression on chemotherapeutic agents were directed only to tumor cells lacking p53. The overexpression of Wip1 in normal tissues provided protection from cisplatin-induced apoptosis through decreased strength of upstream signaling to p53. Thus, Wip1 phosphatase promotes apoptosis in p53-negative tumors and protects normal tissues during treatment with anticancer agents.
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31
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Yagi H, Chuman Y, Kozakai Y, Imagawa T, Takahashi Y, Yoshimura F, Tanino K, Sakaguchi K. A small molecule inhibitor of p53-inducible protein phosphatase PPM1D. Bioorg Med Chem Lett 2011; 22:729-32. [PMID: 22115592 DOI: 10.1016/j.bmcl.2011.10.084] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 10/05/2011] [Accepted: 10/07/2011] [Indexed: 12/29/2022]
Abstract
PPM1D is a p53-inducible Ser/Thr protein phosphatase. PPM1D gene amplification and overexpression have been reported in a variety of human tumors, including breast cancer and neuroblastoma. Because the phosphatase activity of PPM1D is essential for its oncogenic role, PPM1D inhibitors should be viable anti-cancer agents. In our current study, we showed that SPI-001 was a potent and specific PPM1D inhibitor. SPI-001 inhibited PPM1D phosphatase activity in PPM1D-overexpressing human breast cancer cells and increased phosphorylation of p53. Furthermore, SPI-001 suppressed cell proliferation by inducing apoptosis. Our present study suggested that SPI-001 was a potential lead compound in developing anti-cancer drugs.
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Affiliation(s)
- Hiroaki Yagi
- Laboratory of Biological Chemistry, Department of Chemistry, Faculty of Science, North 10, West 8, Kita-ku, Hokkaido University, Sapporo 060-0810, Japan
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Abstract
DNA-damaging therapies represent the most frequently used non-surgical anticancer strategies in the treatment of human tumors. These therapies can kill tumor cells, but at the same time they can be particularly damaging and mutagenic to healthy tissues. The efficacy of DNA-damaging treatments can be improved if tumor cell death is selectively enhanced, and the recent application of poly-(ADP-ribose) polymerase inhibitors in BRCA1/2-deficient tumors is a successful example of this. DNA damage is known to trigger cell-cycle arrest through activation of DNA-damage checkpoints. This arrest can be reversed once the damage has been repaired, but irreparable damage can promote apoptosis or senescence. Alternatively, cells can reenter the cell cycle before repair has been completed, giving rise to mutations. In this review we discuss the mechanisms involved in the activation and inactivation of DNA-damage checkpoints, and how the transition from arrest and cell-cycle re-entry is controlled. In addition, we discuss recent attempts to target the checkpoint in anticancer strategies.
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Darlington Y, Nguyen TA, Moon SH, Herron A, Rao P, Zhu C, Lu X, Donehower LA. Absence of Wip1 partially rescues Atm deficiency phenotypes in mice. Oncogene 2011; 31:1155-65. [PMID: 21765465 PMCID: PMC3197977 DOI: 10.1038/onc.2011.303] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Wild-type p53-induced phosphatase 1 (WIP1) is a serine/threonine phosphatase that dephosphorylates proteins in the ataxia telangiectasia mutated (ATM)-initiated DNA damage response pathway. WIP1 may have a homeostatic role in ATM signaling by returning the cell to a normal pre-stress state following completion of DNA repair. To better understand the effects of WIP1 on ATM signaling, we crossed Atm-deficient mice to Wip1-deficient mice and characterized phenotypes of the double knockout progeny. We hypothesized that the absence of Wip1 might rescue Atm deficiency phenotypes. Atm null mice, like ATM-deficient humans with the inherited syndrome ataxia telangiectasia, exhibit radiation sensitivity, fertility defects, and are T-cell lymphoma prone. Most double knockout mice were largely protected from lymphoma development and had a greatly extended lifespan compared with Atm null mice. Double knockout mice had increased p53 and H2AX phosphorylation and p21 expression compared with their Atm null counterparts, indicating enhanced p53 and DNA damage responses. Additionally, double knockout splenocytes displayed reduced chromosomal instability compared with Atm null mice. Finally, doubly null mice were partially rescued from gametogenesis defects observed in Atm null mice. These results indicate that inhibition of WIP1 may represent a useful strategy for cancer treatment in general and A-T patients in particular.
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Affiliation(s)
- Y Darlington
- Interdepartmental Graduate Program in Cell and Molecular Biology, Houston, Baylor College of Medicine, Houston, TX 77030, USA
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Sosa MS, Avivar-Valderas A, Bragado P, Wen HC, Aguirre-Ghiso JA. ERK1/2 and p38α/β signaling in tumor cell quiescence: opportunities to control dormant residual disease. Clin Cancer Res 2011; 17:5850-7. [PMID: 21673068 DOI: 10.1158/1078-0432.ccr-10-2574] [Citation(s) in RCA: 157] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Systemic minimal residual disease after primary tumor treatment can remain asymptomatic for decades. This is thought to be due to the presence of dormant disseminated tumor cells (DTC) or micrometastases in different organs. DTCs lodged in brain, lungs, livers, and/or bone are a major clinical problem because they are the founders of metastasis, which ultimately kill cancer patients. The problem is further aggravated by our lack of understanding of DTC biology. In consequence, there are almost no rational therapies to prevent dormant DTCs from surviving and expanding. Several cancers, including melanoma as well as breast, prostate, and colorectal carcinomas, undergo dormant periods before metastatic recurrences develop. Here we review our experience in studying the cross-talk between ERK1/2 and p38α/β signaling in models of early cancer progression, dissemination, and DTC dormancy. We also provide some potential translational and clinical applications of these findings and describe how some currently used therapies might be useful to control dormant disease. Finally, we draw caution on the use of p38 inhibitors currently in clinical trials for different diseases as these may accelerate metastasis development.
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Affiliation(s)
- Maria Soledad Sosa
- Department of Medicine, Division of Hematology and Oncology, Tisch Cancer Institute at Mount Sinai, New York, New York, USA
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35
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Hayashi R, Tanoue K, Durell SR, Chatterjee DK, Jenkins LMM, Appella DH, Appella E. Optimization of a cyclic peptide inhibitor of Ser/Thr phosphatase PPM1D (Wip1). Biochemistry 2011; 50:4537-49. [PMID: 21528848 DOI: 10.1021/bi101949t] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PPM1D (PP2Cδ or Wip1) was identified as a wild-type p53-induced Ser/Thr phosphatase that accumulates after DNA damage and classified into the PP2C family. It dephosphorylates and inactivates several proteins critical for cellular stress responses, including p38 MAPK, p53, and ATM. Furthermore, PPM1D is amplified and/or overexpressed in a number of human cancers. Thus, inhibition of its activity could constitute an important new strategy for therapeutic intervention to halt the progression of several different cancers. Previously, we reported the development of a cyclic thioether peptide with low micromolar inhibitory activity toward PPM1D. Here, we describe important improvements in the inhibitory activity of this class of cyclic peptides and also present a binding model based upon the results. We found that specific interaction of an aromatic ring at the X1 position and negative charge at the X5 and X6 positions significantly increased the inhibitory activity of the cyclic peptide, with the optimized molecule having a K(i) of 110 nM. To the best of our knowledge, this represents the highest inhibitory activity reported for an inhibitor of PPM1D. We further developed an inhibitor selective for PPM1D over PPM1A with a K(i) of 2.9 μM. Optimization of the cyclic peptide and mutagenesis experiments suggest that a highly basic loop unique to PPM1D is related to substrate specificity. We propose a new model for the catalytic site of PPM1D and inhibition by the cyclic peptides that will be useful both for the subsequent design of PPM1D inhibitors and for identification of new substrates.
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Affiliation(s)
- Ryo Hayashi
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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36
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Chuman Y, Iizuka K, Honda T, Onoue H, Shimohigashi Y, Sakaguchi K. Phosphatase assay for multi-phosphorylated substrates using phosphatase specific-motif antibody. J Biochem 2011; 150:319-25. [PMID: 21558087 DOI: 10.1093/jb/mvr056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Protein phosphorylation plays central roles in a wide variety of signal transduction pathways and most phosphorylated proteins contain multi-phosphorylated sites. PPM1 type Ser/Thr protein phosphatase family is known to show rigid substrate specificity unlike other Ser/Thr phosphatase PPP family including PP1, PP2A and PP2B. PPM1 type phosphatases are reported to play important roles in growth regulation and in cellular stress signalling. In this study, we developed a phosphatase assay of PPM1D using phosphatase motif-specific antibody. PPM1D is a member of PPM1 type Ser/Thr phosphatase and known to dephosphorylate Ser(P)-Gln sequence. The gene amplification and overexpression of PPM1D were reported in many human cancers. We generated the monoclonal antibody specific for the Ser(P)-Gln sequence, named 3G9-H11. The specificity of this method using ELISA enables the convenient measurement of the dephosphorylation level of only PPM1D target residues of substrate peptides with multiple phosphorylated sites in the presence of multiple phosphatases. In addition, the antibody was applicable to immunoblotting assay for PPM1D function analysis. These results suggested that this method should be very useful for the PPM1D phosphatase assay, including high-throughput analysis and screening of specific inhibitors as anti-cancer drugs. The method using phosphatase motif-specific antibody can be applied to other PPM1 phosphatase family.
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Affiliation(s)
- Yoshiro Chuman
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan
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Abrogation of Wip1 expression by RITA-activated p53 potentiates apoptosis induction via activation of ATM and inhibition of HdmX. Cell Death Differ 2011; 18:1736-45. [PMID: 21546907 DOI: 10.1038/cdd.2011.45] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Inactivation of the p53 tumour suppressor, either by mutation or by overexpression of its inhibitors Hdm2 and HdmX is the most frequent event in cancer. Reactivation of p53 by targeting Hdm2 and HdmX is therefore a promising strategy for therapy. However, Hdm2 inhibitors do not prevent inhibition of p53 by HdmX, which impedes p53-mediated apoptosis. Here, we show that p53 reactivation by the small molecule RITA leads to efficient HdmX degradation in tumour cell lines of different origin and in xenograft tumours in vivo. Notably, HdmX degradation occurs selectively in cancer cells, but not in non-transformed cells. We identified the inhibition of the wild-type p53-induced phosphatase 1 (Wip1) as the major mechanism important for full engagement of p53 activity accomplished by restoration of the ataxia telangiectasia mutated (ATM) kinase-signalling cascade, which leads to HdmX degradation. In contrast to previously reported transactivation of Wip1 by p53, we observed p53-dependent repression of Wip1 expression, which disrupts the negative feedback loop conferred by Wip1. Our study reveals that the depletion of both HdmX and Wip1 potentiates cell death due to sustained activation of p53. Thus, RITA is an example of a p53-reactivating drug that not only blocks Hdm2, but also inhibits two important negative regulators of p53 - HdmX and Wip1, leading to efficient elimination of tumour cells.
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Lambros MB, Natrajan R, Geyer FC, Lopez-Garcia MA, Dedes KJ, Savage K, Lacroix-Triki M, Jones RL, Lord CJ, Linardopoulos S, Ashworth A, Reis-Filho JS. PPM1D gene amplification and overexpression in breast cancer: a qRT-PCR and chromogenic in situ hybridization study. Mod Pathol 2010; 23:1334-45. [PMID: 20543821 DOI: 10.1038/modpathol.2010.121] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
PPM1D (protein phosphatase magnesium-dependent 1δ) maps to the 17q23.2 amplicon and is amplified in ∼8% of breast cancers. The PPM1D gene encodes a serine threonine phosphatase, which is involved in the regulation of several tumour suppressor pathways, including the p53 pathway. Along with others, we have recently shown that PPM1D is one of the drivers of the 17q23.2 amplicon and a promising therapeutic target. Here we investigate whether PPM1D is overexpressed when amplified in breast cancers and the correlations between PPM1D overexpression and amplification with clinicopathological features and survival of breast cancer patients from a cohort of 245 patients with invasive breast cancer treated with therapeutic surgery followed by adjuvant anthracycline-based chemotherapy. mRNA was extracted from representative sections of tumours containing >50% of tumour cells and subjected to TaqMan quantitative real-time PCR using primers for PPM1D and for two housekeeping genes. PPM1D overexpression was defined as the top quartile of expression levels. Chromogenic in situ hybridization with in-house-generated probes for PPM1D was performed. Amplification was defined as >50% of cancer cells with >5 signals per nucleus/large gene clusters. PPM1D overexpression and amplification were found in 25 and 6% of breast cancers, respectively. All cases harbouring PPM1D amplification displayed PPM1D overexpression. PPM1D overexpression was inversely correlated with expression of TOP2A, EGFR and cytokeratins 5/6 and 17. PPM1D amplification was significantly associated with HER2 overexpression, and HER2, TOP2A and CCND1 amplification. No association between PPM1D gene amplification and PPM1D mRNA overexpression with survival was observed. In conclusion, PPM1D is consistently overexpressed when amplified; however, PPM1D overexpression is more pervasive than gene amplification. PPM1D overexpression and amplification are associated with tumours displaying luminal or HER2 phenotypes. Co-amplification of PPM1D and HER2/TOP2A and CCND1 are not random events and may suggest the presence of a 'firestorm' genetic profile.
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Affiliation(s)
- Maryou B Lambros
- The Breakthrough Breast Cancer Research Centre, Institute of Cancer Research, London, UK
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Abstract
The cellular response to DNA damage is a crucial surveillance mechanism that maintains genomic integrity and prevents cancer progression. Previous studies identified multiple Ser/Thr protein kinases that have pivotal roles in the activation of this response. It is interesting that a growing body of evidence suggests that these kinases and their substrates are under tight modulation by numerous Ser/Thr phosphatases. In this study, we review recent reports that reveal new functions and regulation of these phosphatases. Similar to the kinases in this pathway, phosphatases may also be intimately involved in cancer progression and present valuable targets for cancer therapy.
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Bauer JA, Ye F, Marshall CB, Lehmann BD, Pendleton CS, Shyr Y, Arteaga CL, Pietenpol JA. RNA interference (RNAi) screening approach identifies agents that enhance paclitaxel activity in breast cancer cells. Breast Cancer Res 2010; 12:R41. [PMID: 20576088 PMCID: PMC2917036 DOI: 10.1186/bcr2595] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Revised: 06/04/2010] [Accepted: 06/24/2010] [Indexed: 12/31/2022] Open
Abstract
Introduction Paclitaxel is a widely used drug in the treatment of patients with locally advanced and metastatic breast cancer. However, only a small portion of patients have a complete response to paclitaxel-based chemotherapy, and many patients are resistant. Strategies that increase sensitivity and limit resistance to paclitaxel would be of clinical use, especially for patients with triple-negative breast cancer (TNBC). Methods We generated a gene set from overlay of the druggable genome and a collection of genomically deregulated gene transcripts in breast cancer. We used loss-of-function RNA interference (RNAi) to identify gene products in this set that, when targeted, increase paclitaxel sensitivity. Pharmacological agents that targeted the top scoring hits/genes from our RNAi screens were used in combination with paclitaxel, and the effects on the growth of various breast cancer cell lines were determined. Results RNAi screens performed herein were validated by identification of genes in pathways that, when previously targeted, enhanced paclitaxel sensitivity in the pre-clinical and clinical settings. When chemical inhibitors, CCT007093 and mithramycin, against two top hits in our screen, PPMID and SP1, respectively, were used in combination with paclitaxel, we observed synergistic growth inhibition in both 2D and 3D breast cancer cell cultures. The transforming growth factor beta (TGFβ) receptor inhibitor, LY2109761, that targets the signaling pathway of another top scoring hit, TGFβ1, was synergistic with paclitaxel when used in combination on select breast cancer cell lines grown in 3D culture. We also determined the relative paclitaxel sensitivity of 22 TNBC cell lines and identified 18 drug-sensitive and four drug-resistant cell lines. Of significance, we found that both CCT007093 and mithramycin, when used in combination with paclitaxel, resulted in synergistic inhibition of the four paclitaxel-resistant TNBC cell lines. Conclusions RNAi screening can identify druggable targets and novel drug combinations that can sensitize breast cancer cells to paclitaxel. This genomic-based approach can be applied to a multitude of tumor-derived cell lines and drug treatments to generate requisite pre-clinical data for new drug combination therapies to pursue in clinical investigations.
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Affiliation(s)
- Joshua A Bauer
- Department of Biochemistry, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, 2200 Pierce Avenue, Nashville, TN 37232, USA.
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Cha H, Lowe JM, Li H, Lee JS, Belova GI, Bulavin DV, Fornace AJ. Wip1 directly dephosphorylates gamma-H2AX and attenuates the DNA damage response. Cancer Res 2010; 70:4112-22. [PMID: 20460517 DOI: 10.1158/0008-5472.can-09-4244] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The integrity of DNA is constantly challenged throughout the life of a cell by both endogenous and exogenous stresses. A well-organized rapid damage response and proficient DNA repair, therefore, become critically important for maintaining genomic stability and cell survival. When DNA is damaged, the DNA damage response (DDR) can be initiated by alterations in chromosomal structure and histone modifications, such as the phosphorylation of the histone H2AX (the phosphorylated form is referred to as gamma-H2AX). gamma-H2AX plays a crucial role in recruiting DDR factors to damage sites for accurate DNA repair. On repair completion, gamma-H2AX must then be reverted to H2AX by dephosphorylation for attenuation of the DDR. Here, we report that the wild-type p53-induced phosphatase 1 (Wip1) phosphatase, which is often overexpressed in a variety of tumors, effectively dephosphorylates gamma-H2AX in vitro and in vivo. Ectopic expression of Wip1 significantly reduces the level of gamma-H2AX after ionizing as well as UV radiation. Forced premature dephosphorylation of gamma-H2AX by Wip1 disrupts recruitment of important DNA repair factors to damaged sites and delays DNA damage repair. Additionally, deletion of Wip1 enhances gamma-H2AX levels in cells undergoing constitutive oncogenic stress. Taken together, our studies show that Wip1 is an important mammalian phosphatase for gamma-H2AX and shows an additional mechanism for Wip1 in the tumor surveillance network.
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Affiliation(s)
- Hyukjin Cha
- Department of Biochemistry, Georgetown University, Washington, District of Columbia 20057-1468, USA.
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42
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Jain D, Patel N, Shelton M, Basu A, Roque R, Siede W. Enhancement of cisplatin sensitivity by NSC109268 in budding yeast and human cancer cells is associated with inhibition of S-phase progression. Cancer Chemother Pharmacol 2010; 66:945-52. [PMID: 20101404 DOI: 10.1007/s00280-010-1246-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Accepted: 01/09/2010] [Indexed: 01/26/2023]
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Macůrek L, Lindqvist A, Voets O, Kool J, Vos HR, Medema RH. Wip1 phosphatase is associated with chromatin and dephosphorylates γH2AX to promote checkpoint inhibition. Oncogene 2010; 29:2281-91. [DOI: 10.1038/onc.2009.501] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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44
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Song JY, Han HS, Sabapathy K, Lee BM, Yu E, Choi J. Expression of a homeostatic regulator, Wip1 (wild-type p53-induced phosphatase), is temporally induced by c-Jun and p53 in response to UV irradiation. J Biol Chem 2010; 285:9067-76. [PMID: 20093361 DOI: 10.1074/jbc.m109.070003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Wild-type p53-induced phosphatase (Wip1) is induced by p53 in response to stress, which results in the dephosphorylation of proteins (i.e. p38 MAPK, p53, and uracil DNA glycosylase) involved in DNA repair and cell cycle checkpoint pathways. p38 MAPK-p53 signaling is a unique way to induce Wip1 in response to stress. Here, we show that c-Jun directly binds to and activates the Wip1 promoter in response to UV irradiation. The binding of p53 to the promoter occurs earlier than that of c-Jun. In experiments, mutation of the p53 response element (p53RE) or c-Jun consensus sites reduced promoter activity in both non-stressed and stressed A549 cells. Overexpression of p53 significantly decreased Wip1 expression in HCT116 p53(+/+) cells but increased it in HCT116 p53(-/-) cells. Adenovirus-mediated p53 overexpression greatly decreased JNK activity. Up-regulation of Wip1 via the p38 MAPK-p53 and JNK-c-Jun pathways is specific, as demonstrated by our findings that p38 MAPK and JNK inhibitors affected the expression of the Wip1 protein, whereas an ERK inhibitor did not. c-Jun activation occurred much more quickly, and to a greater extent, in A549-E6 cells than in A549 cells, with delayed but fully induced Wip1 expression. These data indicate that Wip1 is activated via both the JNK-c-Jun and p38 MAPK-p53 signaling pathways and that temporal induction of Wip1 depends largely on the balance between c-Jun and p53, which compete for JNK binding. Moreover, our results suggest that JNK-c-Jun-mediated Wip1 induction could serve as a major signaling pathway in human tumors in response to frequent p53 mutation.
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Affiliation(s)
- Ji-young Song
- Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine, 388-1 Pungnap-2 dong, Songpa-gu, Seoul 138-736, Korea
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Lowe JM, Cha H, Yang Q, Fornace AJ. Nuclear factor-kappaB (NF-kappaB) is a novel positive transcriptional regulator of the oncogenic Wip1 phosphatase. J Biol Chem 2009; 285:5249-57. [PMID: 20007970 DOI: 10.1074/jbc.m109.034579] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The nuclear factor-kappaB (NF-kappaB) family of transcription factors plays a key role in inflammation and augments the initiation, promotion, and progression of cancer. NF-kappaB activation generally leads to transcriptional enhancement of genes important in cell survival and cell growth, which is exploited in cancer cells. In this study, we identify an additional oncogene, PPM1D, which encodes for Wip1, as a transcriptional target of NF-kappaB in breast cancer cells. Inhibition of NF-kappaB or activation of NF-kappaB resulted in decreased or increased Wip1 expression, respectively, at both the mRNA and protein levels. PPM1D promoter activity was positively regulated by NF-kappaB, and this regulation was dependent on the presence of the conserved kappaB site in the PPM1D promoter region. Chromatin immunoprecipitation analysis showed basal binding of the p65 NF-kappaB subunit to the PPM1D promoter region encompassing the kappaB site, which is enhanced after NF-kappaB activation by tumor necrosis factor-alpha. Finally, we show that Wip1 expression is induced in lipopolysaccharide-stimulated mouse splenic B-cells and is required for maximum proliferation. Taken together, these data suggest an additional mechanism by which NF-kappaB may promote tumorigenesis, support the selective use of NF-kappaB inhibitors as chemotherapeutic agents for the treatment of human cancers, and further define a function for Wip1 in inflammation.
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Affiliation(s)
- Julie M Lowe
- Department of Biochemistry and Molecular and Cellular Biology, Lombardi Comprehensive Center, Georgetown University, Washington, DC 20057, USA
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Le Guezennec X, Bulavin DV. WIP1 phosphatase at the crossroads of cancer and aging. Trends Biochem Sci 2009; 35:109-14. [PMID: 19879149 DOI: 10.1016/j.tibs.2009.09.005] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2009] [Revised: 09/10/2009] [Accepted: 09/10/2009] [Indexed: 01/07/2023]
Abstract
The PP2C family serine/threonine phosphatase WIP1 is characterized by distinctive oncogenic properties mediated by inhibitory functions on several tumor suppressor pathways, including ATM, CHK2, p38MAPK and p53. PPM1D, the gene encoding WIP1, is aberrantly amplified in different types of human primary cancers, and its deletion in mice results in a profound tumor-resistant phenotype. Numerous downstream targets of WIP1 have been identified, and genetic studies confirm that some play a part in tumorigenesis. Recent evidence highlights a new role for WIP1 in the regulation of a cell-autonomous decline in proliferation of certain self-renewing cell types, including pancreatic beta-cells, with advancing age. These emerging functions of WIP1 make it a potent therapeutic target against cancer and aging.
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Affiliation(s)
- Xavier Le Guezennec
- Institute of Molecular and Cell Biology, Cell Cycle Control and Tumorigenesis Group, 61 Biopolis Drive, Proteos, Singapore
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47
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Wip1, an oncogene targeting tumor suppressors expressed in intestinal stem cells. CURRENT COLORECTAL CANCER REPORTS 2009. [DOI: 10.1007/s11888-009-0027-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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McConnell JL, Wadzinski BE. Targeting protein serine/threonine phosphatases for drug development. Mol Pharmacol 2009; 75:1249-61. [PMID: 19299564 DOI: 10.1124/mol.108.053140] [Citation(s) in RCA: 127] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
With the recent clinical success of drugs targeting protein kinase activity, drug discovery efforts are focusing on the role of reversible protein phosphorylation in disease states. The activity of protein phosphatases, enzymes that oppose protein kinases, can also be manipulated to alter cellular signaling for therapeutic benefits. In this review, we present protein serine/threonine phosphatases as viable therapeutic targets, discussing past successes, current challenges, and future strategies for modulating phosphatase activity.
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Affiliation(s)
- Jamie L McConnell
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-6600, USA
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49
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Chuman Y, Kurihashi W, Mizukami Y, Nashimoto T, Yagi H, Sakaguchi K. PPM1D430, a novel alternative splicing variant of the human PPM1D, can dephosphorylate p53 and exhibits specific tissue expression. J Biochem 2008; 145:1-12. [PMID: 18845566 DOI: 10.1093/jb/mvn135] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
PPM1D is a PPM1 type protein phosphatase and is induced in response to DNA damage. PPM1D-deficient mice show defects in spermatogenesis and lymphoid cell functions but the mechanisms underlying these phenotypes remain unknown. In our current study, we identify and characterize an alternative splicing variant (denoted PPM1D430) of human PPM1D at both the mRNA and protein level. PPM1D430 comprises the common 420 residues of the known PPM1D protein (PPM1D605) and contains a stretch of PPM1D430-specific 10 amino acids. Semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed that PPM1D430 mRNA is also induced in response to the genotoxic stress in a p53-dependent manner. In vitro phosphatase analysis and PPM1D430-specific RNA interference analysis further indicated that PPM1D430 can dephosphorylate Ser15 of human p53 both in vitro and in vivo. On the other hand, expression profiling of this gene by RT-PCR analysis of a human tissue cDNA panel revealed that PPM1D430 is expressed exclusively in testes and in leucocytes whereas PPM1D605 is ubiquitous. In addition, PPM1D430 shows a different subcellular localization pattern and protein stability when compared with PPM1D605 under some conditions. Our current findings thus suggest that PPM1D430 may exert specific functions in immune response and/or spermatogenesis.
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Affiliation(s)
- Yoshiro Chuman
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan
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50
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Lu X, Nguyen TA, Moon SH, Darlington Y, Sommer M, Donehower LA. The type 2C phosphatase Wip1: an oncogenic regulator of tumor suppressor and DNA damage response pathways. Cancer Metastasis Rev 2008; 27:123-35. [PMID: 18265945 PMCID: PMC2362138 DOI: 10.1007/s10555-008-9127-x] [Citation(s) in RCA: 198] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The Wild-type p53-induced phosphatase 1, Wip1 (or PPM1D), is unusual in that it is a serine/threonine phosphatase with oncogenic activity. A member of the type 2C phosphatases (PP2Cδ), Wip1 has been shown to be amplified and overexpressed in multiple human cancer types, including breast and ovarian carcinomas. In rodent primary fibroblast transformation assays, Wip1 cooperates with known oncogenes to induce transformed foci. The recent identification of target proteins that are dephosphorylated by Wip1 has provided mechanistic insights into its oncogenic functions. Wip1 acts as a homeostatic regulator of the DNA damage response by dephosphorylating proteins that are substrates of both ATM and ATR, important DNA damage sensor kinases. Wip1 also suppresses the activity of multiple tumor suppressors, including p53, ATM, p16INK4a and ARF. We present evidence that the suppression of p53, p38 MAP kinase, and ATM/ATR signaling pathways by Wip1 are important components of its oncogenicity when it is amplified and overexpressed in human cancers.
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Affiliation(s)
- Xiongbin Lu
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA
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