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Feng L, Li M, Hu X, Li Y, Zhu L, Chen M, Wei Q, Xu W, Zhou Q, Wang W, Chen D, Wang X, Jin H. CK1δ stimulates ubiquitination-dependent proteasomal degradation of ATF4 to promote chemoresistance in gastric Cancer. Clin Transl Med 2021; 11:e587. [PMID: 34709767 PMCID: PMC8516343 DOI: 10.1002/ctm2.587] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 08/25/2021] [Accepted: 09/14/2021] [Indexed: 12/03/2022] Open
Abstract
Chemoresistance remains a major obstacle to successful cancer therapy, especially for advanced cancers. It used to be recognised as a stable outcome resulting from genetic changes. However, recent studies showed that chemoresistance can also be unstable and reversible with the involvement of non-genetic alterations. In the present study, we found that activating transcription factor 4 (ATF4) is downregulated in chemoresistant gastric cancer cells. The over-expression of ATF4 reversed chemoresistance by activating CHOP transcription to enhance drug-induced apoptosis, and vice versa. Moreover, casein kinase 1 delta (CK1δ) was identified as the kinase responsible for ATF4-S219 phosphorylation, which triggered βTrCP-mediated ATF4 polyubiquitination to promote its proteasomal degradation subsequently. Interestingly, drug withdrawal gradually restored chemosensitivity as well as ATF4 expression in chemoresistant cells, highlighting the dependence of dynamic drug resistance on ATF4 protein expression. In line with these findings, the inhibition of ATF4 protein degradation by CK1δ or proteasome inhibitors overcame chemoresistance both in vitro and in vivo. Taken together, these results indicate that CK1δ stimulates βTrCP-dependent ATF4 polyubiquitination and subsequent proteasomal degradation to promote chemoresistance in gastric cancer. Stabilisation of the ATF4 protein with bortezomib (BTZ), an anticancer drug that inhibits proteasomal degradation, might be a rational strategy to improve chemotherapeutic efficacy in gastric cancer.
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Affiliation(s)
- Lifeng Feng
- Laboratory of Cancer BiologyKey Lab of Biotherapy in ZhejiangCancer Center of Zhejiang UniversitySir Run Run Shaw HospitalMedical School of Zhejiang UniversityHangzhouChina
| | - Muchun Li
- Laboratory of Cancer BiologyKey Lab of Biotherapy in ZhejiangCancer Center of Zhejiang UniversitySir Run Run Shaw HospitalMedical School of Zhejiang UniversityHangzhouChina
| | - Xinyang Hu
- Laboratory of Cancer BiologyKey Lab of Biotherapy in ZhejiangCancer Center of Zhejiang UniversitySir Run Run Shaw HospitalMedical School of Zhejiang UniversityHangzhouChina
| | - Yiling Li
- Laboratory of Cancer BiologyKey Lab of Biotherapy in ZhejiangCancer Center of Zhejiang UniversitySir Run Run Shaw HospitalMedical School of Zhejiang UniversityHangzhouChina
| | - Liyuan Zhu
- Laboratory of Cancer BiologyKey Lab of Biotherapy in ZhejiangCancer Center of Zhejiang UniversitySir Run Run Shaw HospitalMedical School of Zhejiang UniversityHangzhouChina
| | - Miaoqin Chen
- Laboratory of Cancer BiologyKey Lab of Biotherapy in ZhejiangCancer Center of Zhejiang UniversitySir Run Run Shaw HospitalMedical School of Zhejiang UniversityHangzhouChina
| | - Qi Wei
- Laboratory of Cancer BiologyKey Lab of Biotherapy in ZhejiangCancer Center of Zhejiang UniversitySir Run Run Shaw HospitalMedical School of Zhejiang UniversityHangzhouChina
| | - Wenxia Xu
- Central LaboratoryAffiliated Jinhua HospitalMedical School of Zhejiang UniversityJinhuaZhejiangChina
| | - Qiyin Zhou
- Laboratory of Cancer BiologyKey Lab of Biotherapy in ZhejiangCancer Center of Zhejiang UniversitySir Run Run Shaw HospitalMedical School of Zhejiang UniversityHangzhouChina
| | - Weikai Wang
- Laboratory of Cancer BiologyKey Lab of Biotherapy in ZhejiangCancer Center of Zhejiang UniversitySir Run Run Shaw HospitalMedical School of Zhejiang UniversityHangzhouChina
| | - Dingwei Chen
- Department of General SurgerySir Run Run Shaw HospitalMedical School of Zhejiang UniversityHangzhouChina
| | - Xian Wang
- Department of Medical OncologySir Run Run Shaw HospitalMedical School of Zhejiang UniversityHangzhouChina
| | - Hongchuan Jin
- Laboratory of Cancer BiologyKey Lab of Biotherapy in ZhejiangCancer Center of Zhejiang UniversitySir Run Run Shaw HospitalMedical School of Zhejiang UniversityHangzhouChina
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Mdm2 phosphorylation by Akt regulates the p53 response to oxidative stress to promote cell proliferation and tumorigenesis. Proc Natl Acad Sci U S A 2021; 118:2003193118. [PMID: 33468664 DOI: 10.1073/pnas.2003193118] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
We have shown previously that phosphorylation of Mdm2 by ATM and c-Abl regulates Mdm2-p53 signaling and alters the effects of DNA damage in mice, including bone marrow failure and tumorigenesis induced by ionizing radiation. Here, we examine the physiological effects of Mdm2 phosphorylation by Akt, another DNA damage effector kinase. Surprisingly, Akt phosphorylation of Mdm2 does not alter the p53-mediated effects of ionizing radiation in cells or mice but regulates the p53 response to oxidative stress. Akt phosphorylation of Mdm2 serine residue 183 increases nuclear Mdm2 stability, decreases p53 levels, and prevents senescence in primary cells exposed to reactive oxidative species (ROS). Using multiple mouse models of ROS-induced cancer, we show that Mdm2 phosphorylation by Akt reduces senescence to promote KrasG12D-driven lung cancers and carcinogen-induced papilloma and hepatocellular carcinomas. Collectively, we document a unique physiologic role for Akt-Mdm2-p53 signaling in regulating cell growth and tumorigenesis in response to oxidative stress.
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Islam S, Dutta P, Sahay O, Santra MK. β-TrCP1 facilitates cell cycle checkpoint activation, DNA repair, and cell survival through ablation of β-TrCP2 in response to genotoxic stress. J Biol Chem 2021; 296:100511. [PMID: 33676897 PMCID: PMC8093472 DOI: 10.1016/j.jbc.2021.100511] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 02/24/2021] [Accepted: 03/03/2021] [Indexed: 11/22/2022] Open
Abstract
F-box proteins β-TrCP1 and β-TrCP2 are paralogs present in the human genome. They control several cellular processes including cell cycle and DNA damage signaling. Moreover, it is reported that they facilitate DNA damage-induced accumulation of p53 by directing proteasomal degradation of MDM2, a protein that promotes p53 degradation. However, the individual roles of β-TrCP1 and β-TrCP2 in the genotoxic stress-induced activation of cell cycle checkpoints and DNA damage repair remain largely unknown. Here, using biochemical, molecular biology, flow cytometric, and immunofluorescence techniques, we show that β-TrCP1 and β-TrCP2 communicate during genotoxic stress. We found that expression levels of β-TrCP1 are significantly increased while levels of β-TrCP2 are markedly decreased upon induction of genotoxic stress. Further, our results revealed that DNA damage-induced activation of ATM kinase plays an important role in maintaining the reciprocal expression levels of β-TrCP1 and β-TrCP2 via the phosphorylation of β-TrCP1 at Ser158. Phosphorylated β-TrCP1 potently promotes the proteasomal degradation of β-TrCP2 and MDM2, resulting in the activation of p53. Additionally, β-TrCP1 impedes MDM2 accumulation via abrogation of its lysine 63-linked polyubiquitination by β-TrCP2. Thus, β-TrCP1 helps to arrest cells at the G2/M phase of the cell cycle and promotes DNA repair upon DNA damage through attenuation of β-TrCP2. Collectively, our findings elucidate an intriguing posttranslational regulatory mechanism of these two paralogs under genotoxic stress and revealed β-TrCP1 as a key player in maintaining the genome integrity through the attenuation of β-TrCP2 levels in response to genotoxic stress.
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Affiliation(s)
- Sehbanul Islam
- Molecular Oncology Laboratory, National Centre for Cell Science, Pune, Maharashtra, India; Department of Biotechnology, Savitribai Phule Pune University, Pune, Maharashtra, India
| | - Parul Dutta
- Molecular Oncology Laboratory, National Centre for Cell Science, Pune, Maharashtra, India; Department of Biotechnology, Savitribai Phule Pune University, Pune, Maharashtra, India
| | - Osheen Sahay
- Molecular Oncology Laboratory, National Centre for Cell Science, Pune, Maharashtra, India; Department of Biotechnology, Savitribai Phule Pune University, Pune, Maharashtra, India
| | - Manas Kumar Santra
- Molecular Oncology Laboratory, National Centre for Cell Science, Pune, Maharashtra, India.
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4
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Davis CK, Vemuganti R. DNA damage and repair following traumatic brain injury. Neurobiol Dis 2020; 147:105143. [PMID: 33127471 DOI: 10.1016/j.nbd.2020.105143] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 10/09/2020] [Accepted: 10/23/2020] [Indexed: 01/05/2023] Open
Abstract
Traumatic brain injury (TBI) is known to promote significant DNA damage irrespective of age, sex, and species. Chemical as well as structural DNA modification start within minutes and persist for days after TBI. Although several DNA repair pathways are induced following TBI, the simultaneous downregulation of some of the genes and proteins of these pathways leads to an aberrant overall DNA repair process. In many instances, DNA damages escape even the most robust repair mechanisms, especially when the repair process becomes overwhelmed or becomes inefficient by severe or repeated injuries. The persisting DNA damage and/or lack of DNA repair contributes to long-term functional deficits. In this review, we discuss the mechanisms of TBI-induced DNA damage and repair. We further discussed the putative experimental therapies that target the members of the DNA repair process for improved outcome following TBI.
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Affiliation(s)
- Charles K Davis
- Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA
| | - Raghu Vemuganti
- Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA; William S. Middleton VA Hospital, Madison, WI, USA.
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5
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SCF β-TrCP-mediated degradation of TOP2β promotes cancer cell survival in response to chemotherapeutic drugs targeting topoisomerase II. Oncogenesis 2020; 9:8. [PMID: 32015321 PMCID: PMC6997367 DOI: 10.1038/s41389-020-0196-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 12/10/2019] [Accepted: 01/10/2020] [Indexed: 12/17/2022] Open
Abstract
Topoisomerase II (TOP2)-targeting anticancer chemotherapeutic drugs, termed TOP2 poisons, are widely used and effective in the clinic by stabilizing TOP2-DNA covalent complexes to induce DNA double-strand breaks (DSBs) and ultimately, cause cell death. The stabilized TOP2-DNA complex is known to be degraded by proteasome, whereas the underlying mechanism for instant TOP2β degradation in response to TOP2 poisons and the subsequent biological consequence remain elusive. Here, we reported that TOP2 poison-induced TOP2β degradation is mediated by SCFβ-TrCP ubiquitin ligase. Specifically, DNA damage signal, triggered by teniposide (VM-26) treatment, activates ATM, cooperating with CK1 to phosphorylate TOP2β on Ser1134 and Ser1130, respectively, in a canonical degron motif to facilitate β-TrCP binding and subsequent degradation. Inactivation of ATM, CK1 or SCFβ-TrCP by small molecular inhibitors or genetic knockdown/knockout abrogates TOP2β degradation. Biologically, blockage of TOP2β degradation in combination with VM-26 treatment impairs DNA damage response and repair, leading to an accelerated cell death via apoptosis. Thus, it appears that TOP2β degradation is a cellular defensive mechanism to facilitate the exposure of DSBs to trigger DNA damage response and repair. Collectively, our findings reveal a new strategy to improve the efficacy of TOP2 poisons in combination with small-molecule inhibitors against TOP2β degradation.
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Pérez-Benavente B, Nasresfahani AF, Farràs R. Ubiquitin-Regulated Cell Proliferation and Cancer. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1233:3-28. [PMID: 32274751 DOI: 10.1007/978-3-030-38266-7_1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Ubiquitin ligases (E3) play a crucial role in the regulation of different cellular processes such as proliferation and differentiation via recognition, interaction, and ubiquitination of key cellular proteins in a spatial and temporal regulated manner. The type of ubiquitin chain formed determines the fate of the substrates. The ubiquitinated substrates can be degraded by the proteasome, display altered subcellular localization, or can suffer modifications on their interaction with functional protein complexes. Deregulation of E3 activities is frequently found in various human pathologies, including cancer. The illegitimated or accelerated degradation of oncosuppressive proteins or, inversely, the abnormally high accumulation of oncoproteins, contributes to cell proliferation and transformation. Anomalies in protein abundance may be related to mutations that alter the direct or indirect recognition of proteins by the E3 enzymes or alterations in the level of expression or activity of ubiquitin ligases. Through a few examples, we illustrate here the complexity and diversity of the molecular mechanisms related to protein ubiquitination involved in cell cycle regulation. We will discuss the role of ubiquitin-dependent degradation mediated by the proteasome, the role of non-proteolytic ubiquitination during cell cycle progression, and the consequences of this deregulation on cellular transformation. Finally, we will highlight the novel opportunities that arise from these studies for therapeutic intervention.
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Affiliation(s)
| | | | - Rosa Farràs
- Oncogenic Signaling Laboratory, Centro de Investigación Príncipe Felipe, Valencia, Spain.
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Schwab N, Grenier K, Hazrati LN. DNA repair deficiency and senescence in concussed professional athletes involved in contact sports. Acta Neuropathol Commun 2019; 7:182. [PMID: 31727161 PMCID: PMC6857343 DOI: 10.1186/s40478-019-0822-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 09/29/2019] [Indexed: 12/11/2022] Open
Abstract
Mild traumatic brain injury (mTBI) leads to diverse symptoms including mood disorders, cognitive decline, and behavioral changes. In some individuals, these symptoms become chronic and persist in the long-term and can confer an increased risk of neurodegenerative disease and dementia diagnosis later in life. Despite the severity of its consequences, the pathophysiological mechanism of mTBI remains unknown. In this post-mortem case series, we assessed DNA damage-induced cellular senescence pathways in 38 professional athletes with a history of repeated mTBI and ten controls with no mTBI history. We assessed clinical presentation, neuropathological changes, load of DNA damage, morphological markers of cellular senescence, and expression of genes involved in DNA damage signaling, DNA repair, and cellular senescence including the senescence-associated secretory phenotype (SASP). Twenty-eight brains with past history of repeated mTBI history had DNA damage within ependymal cells, astrocytes, and oligodendrocytes. DNA damage burden was increased in brains with proteinopathy compared to those without. Cases also showed hallmark features of cellular senescence in glial cells including astrocytic swelling, beading of glial cell processes, loss of H3K27Me3 (trimethylation at lysine 27 of histone H3) and lamin B1 expression, and increased expression of cellular senescence and SASP pathways. Neurons showed a spectrum of changes including loss of emerin nuclear membrane expression, loss of Brahma-related gene-1 (BRG1 or SMARCA4) expression, loss of myelin basic protein (MBP) axonal expression, and translocation of intranuclear tau to the cytoplasm. Expression of DNA repair proteins was decreased in mTBI brains. mTBI brains showed substantial evidence of DNA damage and cellular senescence. Decreased expression of DNA repair genes suggests inefficient DNA repair pathways in this cohort, conferring susceptibly to cellular senescence and subsequent brain dysfunction after mTBI. We therefore suggest that brains of contact-sports athletes are characterized by deficient DNA repair and DNA damage-induced cellular senescence and propose that this may affect neurons and be the driver of brain dysfunction in mTBI, predisposing the progression to neurodegenerative diseases. This study provides novel targets for diagnostic and prognostic biomarkers, and represents viable targets for future treatments.
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Affiliation(s)
- Nicole Schwab
- Department of Laboratory Medicine and Pathobiology, University of Toronto, 1 King's College Cir, Toronto, ON, M5S 1A8, Canada
- The Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1X8, Canada
- Canadian Concussion Centre, Toronto Western Hospital, Toronto, ON, Canada
| | - Karl Grenier
- Department of Laboratory Medicine and Pathobiology, University of Toronto, 1 King's College Cir, Toronto, ON, M5S 1A8, Canada
- The Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1X8, Canada
| | - Lili-Naz Hazrati
- Department of Laboratory Medicine and Pathobiology, University of Toronto, 1 King's College Cir, Toronto, ON, M5S 1A8, Canada.
- The Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1X8, Canada.
- Canadian Concussion Centre, Toronto Western Hospital, Toronto, ON, Canada.
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8
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Xu P, Ianes C, Gärtner F, Liu C, Burster T, Bakulev V, Rachidi N, Knippschild U, Bischof J. Structure, regulation, and (patho-)physiological functions of the stress-induced protein kinase CK1 delta (CSNK1D). Gene 2019; 715:144005. [PMID: 31376410 PMCID: PMC7939460 DOI: 10.1016/j.gene.2019.144005] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/19/2019] [Accepted: 07/23/2019] [Indexed: 12/11/2022]
Abstract
Members of the highly conserved pleiotropic CK1 family of serine/threonine-specific kinases are tightly regulated in the cell and play crucial regulatory roles in multiple cellular processes from protozoa to human. Since their dysregulation as well as mutations within their coding regions contribute to the development of various different pathologies, including cancer and neurodegenerative diseases, they have become interesting new drug targets within the last decade. However, to develop optimized CK1 isoform-specific therapeutics in personalized therapy concepts, a detailed knowledge of the regulation and functions of the different CK1 isoforms, their various splice variants and orthologs is mandatory. In this review we will focus on the stress-induced CK1 isoform delta (CK1δ), thereby addressing its regulation, physiological functions, the consequences of its deregulation for the development and progression of diseases, and its potential as therapeutic drug target.
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Affiliation(s)
- Pengfei Xu
- Department of General and Visceral Surgery, Surgery Center, Ulm University Hospital, Albert-Einstein-Allee 23, 89081 Ulm, Germany.
| | - Chiara Ianes
- Department of General and Visceral Surgery, Surgery Center, Ulm University Hospital, Albert-Einstein-Allee 23, 89081 Ulm, Germany.
| | - Fabian Gärtner
- Department of General and Visceral Surgery, Surgery Center, Ulm University Hospital, Albert-Einstein-Allee 23, 89081 Ulm, Germany.
| | - Congxing Liu
- Department of General and Visceral Surgery, Surgery Center, Ulm University Hospital, Albert-Einstein-Allee 23, 89081 Ulm, Germany.
| | - Timo Burster
- Department of Biology, School of Science and Technology, Nazarbayev University, 53 Kabanbay Batyr Ave, Nur-Sultan 020000, Kazakhstan.
| | - Vasiliy Bakulev
- Ural Federal University named after the first President of Russia B. N. Eltsin, Technology for Organic Synthesis Laboratory, 19 Mirastr., 620002 Ekaterinburg, Russia.
| | - Najma Rachidi
- Unité de Parasitologie Moléculaire et Signalisation, Department of Parasites and Insect Vectors, Institut Pasteur and INSERM U1201, 25-28 Rue du Dr Roux, 75015 Paris, France.
| | - Uwe Knippschild
- Department of General and Visceral Surgery, Surgery Center, Ulm University Hospital, Albert-Einstein-Allee 23, 89081 Ulm, Germany.
| | - Joachim Bischof
- Department of General and Visceral Surgery, Surgery Center, Ulm University Hospital, Albert-Einstein-Allee 23, 89081 Ulm, Germany.
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9
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SCF FBXO22 targets HDM2 for degradation and modulates breast cancer cell invasion and metastasis. Proc Natl Acad Sci U S A 2019; 116:11754-11763. [PMID: 31138683 DOI: 10.1073/pnas.1820990116] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Human homolog of mouse double minute 2 (HDM2) is an oncogene frequently overexpressed in cancers with poor prognosis, but mechanisms of controlling its abundance remain elusive. In an unbiased biochemical search, we discovered Skp1-Cullin 1-FBXO22-ROC1 (SCFFBXO22) as the most dominating HDM2 E3 ubiquitin ligase from human proteome. The results of protein decay rate analysis, ubiquitination, siRNA-mediated silencing, and coimmunoprecipitation experiments support a hypothesis that FBXO22 targets cellular HDM2 for ubiquitin-dependent degradation. In human breast cancer cells, FBXO22 knockdown (KD) increased cell invasiveness, which was driven by elevated levels of HDM2. Moreover, mouse 4T1 breast tumor model studies revealed that FBXO22 KD led to a significant increase of breast tumor cell metastasis to the lung. Finally, low FBXO22 expression is correlated with worse survival and high HDM2 expression in human breast cancer. Altogether, these findings suggest that SCFFBXO22 targets HDM2 for degradation and possesses inhibitory effects against breast cancer tumor cell invasion and metastasis.
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10
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Borg NA, Dixit VM. Ubiquitin in Cell-Cycle Regulation and Dysregulation in Cancer. ANNUAL REVIEW OF CANCER BIOLOGY-SERIES 2017. [DOI: 10.1146/annurev-cancerbio-040716-075607] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Uncontrolled cell proliferation and genomic instability are common features of cancer and can arise from, respectively, the loss of cell-cycle control and defective checkpoints. Ubiquitin-mediated proteolysis, ultimately executed by ubiquitin-ligating enzymes (E3s), plays a key part in cell-cycle regulation and is dominated by two multisubunit E3s, the anaphase-promoting complex (or cyclosome) (APC/C) and SKP1–cullin-1–F-box (SCF) complex. We highlight the role of APC/C and the SCF bound to F-box proteins, FBXW7, SKP2, and β-TrCP, in regulating the abundance of select fundamental proteins, primarily during the cell cycle, that are associated with human cancer. The clinical success of the first proteasome inhibitor, bortezomib, in treating multiple myeloma and mantle-cell lymphoma set the precedent for viewing the ubiquitin–proteasome system as a druggable target for cancer. Given that there are more E3s than kinases, selective, small-molecule E3 inhibitors have the potential of opening up another dimension in the therapeutic armamentarium for the treatment of cancer.
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Affiliation(s)
- Natalie A. Borg
- Cancer Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
| | - Vishva M. Dixit
- Department of Physiological Chemistry, Genentech Inc., South San Francisco, California 94080
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11
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Carr MI, Jones SN. Regulation of the Mdm2-p53 signaling axis in the DNA damage response and tumorigenesis. Transl Cancer Res 2016; 5:707-724. [PMID: 28690977 PMCID: PMC5501481 DOI: 10.21037/tcr.2016.11.75] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The p53 tumor suppressor acts as a guardian of the genome in mammalian cells undergoing DNA double strand breaks induced by a various forms of cell stress, including inappropriate growth signals or ionizing radiation. Following damage, p53 protein levels become greatly elevated in cells and p53 functions primarily as a transcription factor to regulate the expression a wide variety of genes that coordinate this DNA damage response. In cells undergoing high amounts of DNA damage, p53 can promote apoptosis, whereas in cells undergoing less damage, p53 promotes senescence or transient cell growth arrest and the expression of genes involved in DNA repair, depending upon the cell type and level of damage. Failure of the damaged cell to undergo growth arrest or apoptosis, or to respond to the DNA damage by other p53-coordinated mechanisms, can lead to inappropriate cell growth and tumorigenesis. In cells that have successfully responded to genetic damage, the amount of p53 present in the cell must return to basal levels in order for the cell to resume normal growth and function. Although regulation of p53 levels and function is coordinated by many proteins, it is now widely accepted that the master regulator of p53 is Mdm2. In this review, we discuss the role(s) of p53 in the DNA damage response and in tumor suppression, and how post-translational modification of Mdm2 regulates the Mdm2-p53 signaling axis to govern p53 activities in the cell.
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Affiliation(s)
- Michael I Carr
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Stephen N Jones
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
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12
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RNF12 promotes p53-dependent cell growth suppression and apoptosis by targeting MDM2 for destruction. Cancer Lett 2016; 375:133-141. [PMID: 26926424 DOI: 10.1016/j.canlet.2016.02.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 01/28/2016] [Accepted: 02/09/2016] [Indexed: 01/06/2023]
Abstract
The oncoprotein MDM2 is an E3 ubiquitin ligase that targets tumor suppressor p53 for ubiquitination and proteasomal degradation, restraining the potent activity of p53 and enabling cell survival and proliferation. Dysregulation of MDM2-p53 axis was frequently observed in human cancers. Originally, it is proposed that MDM2 degradation was mainly achieved by destructive self-ubiquitination. However, recent study suggests that MDM2 may be targeted for degradation by an external E3 ubiquitin ligase(s) under physiological levels. Here, we identified E3 ubiquitin ligase RNF12 as an MDM2-interacting protein through yeast two hybrid methods. We demonstrated that RNF12 targets MDM2 for ubiquitination and proteasomal-dependent degradation, which is independent of MDM2's self-ubiquitination activity. Accordingly, RNF12 elevates p53 protein level by abrogating MDM2-mediated p53 degradation and ubiquitination. Finally, we showed that RNF12 regulates cell growth suppression and DNA damage-induced apoptosis in a p53-dependent manner. Taken together, we establish RNF12 as a novel positive regulator of p53 pathway and an external E3 ubiquitin ligase for MDM2 destruction. These data shed light on the potential roles of RNF12 in MDM2-p53 axis and tumor suppression.
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13
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SCF(β-TRCP) promotes cell growth by targeting PR-Set7/Set8 for degradation. Nat Commun 2015; 6:10185. [PMID: 26666832 PMCID: PMC4682171 DOI: 10.1038/ncomms10185] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 11/12/2015] [Indexed: 12/21/2022] Open
Abstract
The Set8/PR-Set7/KMT5a methyltransferase plays critical roles in governing transcriptional regulation, cell cycle progression and tumorigenesis. Although CRL4(Cdt2) was reported to regulate Set8 stability, deleting the PIP motif only led to partial resistance to ultraviolet-induced degradation of Set8, indicating the existence of additional E3 ligase(s) controlling Set8 stability. Furthermore, it remains largely undefined how DNA damage-induced kinase cascades trigger the timely destruction of Set8 to govern tumorigenesis. Here, we report that SCF(β-TRCP) earmarks Set8 for ubiquitination and degradation in a casein kinase I-dependent manner, which is activated by DNA-damaging agents. Biologically, both CRL4(Cdt2) and SCF(β-TRCP)-mediated pathways contribute to ultraviolet-induced Set8 degradation to control cell cycle progression, governing the onset of DNA damage-induced checkpoints. Therefore, like many critical cell cycle regulators including p21 and Cdt1, we uncover a tight regulatory network to accurately control Set8 abundance. Our studies further suggest that aberrancies in this delicate degradation pathway might contribute to aberrant elevation of Set8 in human tumours.
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14
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Li J, Kurokawa M. Regulation of MDM2 Stability After DNA Damage. J Cell Physiol 2015; 230:2318-27. [PMID: 25808808 DOI: 10.1002/jcp.24994] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 03/20/2015] [Indexed: 12/13/2022]
Abstract
Cells in our body are constantly exposed to various stresses and threats to their genomic integrity. The tumor suppressor protein p53 plays a critical role in successful defense against these threats by inducing apoptotic cell death or cell cycle arrest. In unstressed conditions, p53 levels and activity must be kept low to prevent lethal activation of apoptotic and senescence pathways. However, upon DNA damage or other stressors, p53 is released from its inhibitory state to induce an array of apoptosis and cell cycle genes. Conversely, inactivation of p53 could promote unrestrained tumor proliferation and failure to appropriately undergo apoptotic cell death, which could, in turn, lead to carcinogenesis. The ubiquitin E3 ligase MDM2 is the most critical inhibitor of p53 that determines the cellular response to various p53-activating agents, including DNA damage. MDM2 activity is controlled by post-translational modifications, especially phosphorylation. However, accumulating evidence suggests that MDM2 is also regulated at the level of protein stability, which is controlled by the ubiquitin-proteasome pathway. Here, we discuss how MDM2 can be regulated in response to DNA damage with particular focus on the regulation of MDM2 protein stability.
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Affiliation(s)
- Jiaqi Li
- Pharmacology and Toxicology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire
| | - Manabu Kurokawa
- Pharmacology and Toxicology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire.,Norris Cotton Cancer Center, Lebanon, New Hampshire
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15
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Gan W, Dai X, Lunardi A, Li Z, Inuzuka H, Liu P, Varmeh S, Zhang J, Cheng L, Sun Y, Asara JM, Beck AH, Huang J, Pandolfi PP, Wei W. SPOP Promotes Ubiquitination and Degradation of the ERG Oncoprotein to Suppress Prostate Cancer Progression. Mol Cell 2015; 59:917-30. [PMID: 26344095 DOI: 10.1016/j.molcel.2015.07.026] [Citation(s) in RCA: 158] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 06/18/2015] [Accepted: 07/24/2015] [Indexed: 11/29/2022]
Abstract
The ERG gene is fused to TMPRSS2 in approximately 50% of prostate cancers (PrCa), resulting in its overexpression. However, whether this is the sole mechanism underlying ERG elevation in PrCa is currently unclear. Here we report that ERG ubiquitination and degradation are governed by the Cullin 3-based ubiquitin ligase SPOP and that deficiency in this pathway leads to aberrant elevation of the ERG oncoprotein. Specifically, we find that truncated ERG (ΔERG), encoded by the ERG fusion gene, is stabilized by evading SPOP-mediated destruction, whereas prostate cancer-associated SPOP mutants are also deficient in promoting ERG ubiquitination. Furthermore, we show that the SPOP/ERG interaction is modulated by CKI-mediated phosphorylation. Importantly, we demonstrate that DNA damage drugs, topoisomerase inhibitors, can trigger CKI activation to restore the SPOP/ΔERG interaction and its consequent degradation. Therefore, SPOP functions as a tumor suppressor to negatively regulate the stability of the ERG oncoprotein in prostate cancer.
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Affiliation(s)
- Wenjian Gan
- Department of Pathology, Cancer Research Institute, Beth Israel Deaconess Cancer Center, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Xiangpeng Dai
- Department of Pathology, Cancer Research Institute, Beth Israel Deaconess Cancer Center, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Andrea Lunardi
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Zhen Li
- Department of Pathology and Urology, Jonson Comprehensive Cancer Center and Broad Center of Regenerative Medicine and Stem Cell Research, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | - Hiroyuki Inuzuka
- Department of Pathology, Cancer Research Institute, Beth Israel Deaconess Cancer Center, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Pengda Liu
- Department of Pathology, Cancer Research Institute, Beth Israel Deaconess Cancer Center, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Shoreh Varmeh
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jinfang Zhang
- Department of Pathology, Cancer Research Institute, Beth Israel Deaconess Cancer Center, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Liang Cheng
- Department of Pathology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Yin Sun
- Department of Pathology and Urology, Jonson Comprehensive Cancer Center and Broad Center of Regenerative Medicine and Stem Cell Research, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | - John M Asara
- Division of Signal Transduction, Beth Israel Deaconess Medical Center and Department of Medicine, Harvard Medical School, Boston, MA 02215, USA
| | - Andrew H Beck
- Department of Pathology, Cancer Research Institute, Beth Israel Deaconess Cancer Center, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Jiaoti Huang
- Department of Pathology and Urology, Jonson Comprehensive Cancer Center and Broad Center of Regenerative Medicine and Stem Cell Research, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | - Pier Paolo Pandolfi
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
| | - Wenyi Wei
- Department of Pathology, Cancer Research Institute, Beth Israel Deaconess Cancer Center, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
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16
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Malonia SK, Dutta P, Santra MK, Green MR. F-box protein FBXO31 directs degradation of MDM2 to facilitate p53-mediated growth arrest following genotoxic stress. Proc Natl Acad Sci U S A 2015; 112:8632-7. [PMID: 26124108 PMCID: PMC4507212 DOI: 10.1073/pnas.1510929112] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The tumor suppressor p53 plays a critical role in maintaining genomic stability. In response to genotoxic stress, p53 levels increase and induce cell-cycle arrest, senescence, or apoptosis, thereby preventing replication of damaged DNA. In unstressed cells, p53 is maintained at a low level. The major negative regulator of p53 is MDM2, an E3 ubiquitin ligase that directly interacts with p53 and promotes its polyubiquitination, leading to the subsequent destruction of p53 by the 26S proteasome. Following DNA damage, MDM2 is degraded rapidly, resulting in increased p53 stability. Because of the important role of MDM2 in modulating p53 function, it is critical to understand how MDM2 levels are regulated. Here we show that the F-box protein FBXO31, a candidate tumor suppressor encoded in 16q24.3 for which there is loss of heterozygosity in various solid tumors, is responsible for promoting MDM2 degradation. Following genotoxic stress, FBXO31 is phosphorylated by the DNA damage serine/threonine kinase ATM, resulting in increased levels of FBXO31. FBXO31 then interacts with and directs the degradation of MDM2, which is dependent on phosphorylation of MDM2 by ATM. FBXO31-mediated loss of MDM2 leads to elevated levels of p53, resulting in growth arrest. In cells depleted of FBXO31, MDM2 is not degraded and p53 levels do not increase following genotoxic stress. Thus, FBXO31 is essential for the classic robust increase in p53 levels following DNA damage.
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Affiliation(s)
- Sunil K Malonia
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Parul Dutta
- National Centre for Cell Science, University of Pune Campus, Ganeshkhind, Pune, Maharashtra 411007, India
| | - Manas Kumar Santra
- National Centre for Cell Science, University of Pune Campus, Ganeshkhind, Pune, Maharashtra 411007, India;
| | - Michael R Green
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605; Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, MA 01605
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17
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Eskandari-Nasab E, Hashemi M, Amininia S, Ebrahimi M, Rezaei M, Hashemi SM. Effect of TP53 16-bp and β-TrCP 9-bp INS/DEL polymorphisms in relation to risk of breast cancer. Gene 2015; 568:181-5. [PMID: 26003292 DOI: 10.1016/j.gene.2015.05.048] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 05/17/2015] [Accepted: 05/18/2015] [Indexed: 11/17/2022]
Abstract
UNLABELLED P53 as a tumor suppressor and an apoptosis modulator, is the regulator of the cell cycle and apoptosis, and contributes to mammary gland development and breast cancer (BC) progression. BTRC gene (Homo sapiens beta-transducing repeat containing E3 ubiquitin protein ligase) encoded protein, β-TrCP, is a novel regulator of p53. The current study aimed to assess the possible effects of TP53 IVS3 16 bp (rs17878362) and β-TrCP 9 bp (rs16405) INS/DEL polymorphisms on BC risk in an Iranian population. A total of 439 women including 236 BC patients and 203 healthy women were recruited. The TP53 and β-TrCP INS/DEL polymorphisms were genotyped by allele-specific polymerase chain reaction method. Our data demonstrated that the TP53 16-bp INS/DEL variation was associated with an increased risk of BC in codominant (INS/INS vs. DEL/DEL OR=1.82; 95% CI=1.02-3.23; P=0.042) and dominant (Del/INS+INS/INS vs. DEL/DEL OR=1.48; 95% CI=1.03-2.21; P=0.044) models. Additionally, the variant allele (INS) of TP53 DEL/INS polymorphism with a relatively higher frequency in cases than in controls (35.6 vs. 27.8) was a risk factor for BC (OR=1.43; 95% CI=1.06-1.93; P=0.017). With respect to β-TrCP INS/DEL polymorphism, our study failed to find any difference in allele and genotype distribution between BC patients and controls in codominant, dominant and recessive tested inheritance models (P>0.05). Furthermore, no significant association among the β-TrCP and TP53 genotype distribution and clinical characteristics of BC patients were found (P>0.05). Our findings suggest that the TP53 16-bp INS/INS and DEL/INS+INS/INS genotypes as well as the INS allele could be genetic factors related to BC risk.
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Affiliation(s)
- Ebrahim Eskandari-Nasab
- Genetics of Non-Communicable Disease Research Center, Zahedan University of Medical Sciences, Zahedan, Iran; Department of Clinical Biochemistry, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Mohammad Hashemi
- Genetics of Non-Communicable Disease Research Center, Zahedan University of Medical Sciences, Zahedan, Iran; Department of Clinical Biochemistry, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran.
| | - Shadi Amininia
- Department of Clinical Biochemistry, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Mahboubeh Ebrahimi
- Department of Clinical Biochemistry, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Maryam Rezaei
- Department of Clinical Biochemistry, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Seyed Mehdi Hashemi
- Department of Internal Medicine, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran
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18
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Liu J, Wan L, Liu P, Inuzuka H, Liu J, Wang Z, Wei W. SCF(β-TRCP)-mediated degradation of NEDD4 inhibits tumorigenesis through modulating the PTEN/Akt signaling pathway. Oncotarget 2015; 5:1026-37. [PMID: 24657926 PMCID: PMC4011580 DOI: 10.18632/oncotarget.1675] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The HECT domain-containing ubiquitin E3 ligase NEDD4 is widely expressed in mammalian tissues and plays a crucial role in governing a wide spectrum of cellular processes including cell growth, tissue development and homeostasis. Recent reports have indicated that NEDD4 might facilitate tumorigenesis through targeted degradation of multiple tumor suppressor proteins including PTEN. However, the molecular mechanism by which NEDD4 stability is regulated has not been fully elucidated. Here we report that SCF(β-TRCP) governs NEDD4 protein stability by targeting it for ubiquitination and subsequent degradation in a Casein Kinase-I (CKI) phosphorylation-dependent manner. Specifically, depletion of β-TRCP, or inactivation of CKI, stabilized NEDD4, leading to down-regulation of its ubiquitin target PTEN and subsequent activation of the mTOR/Akt oncogenic pathway. Furthermore, we found that CKIδ-mediated phosphorylation of Ser347 and Ser348 on NEDD4 promoted its interaction with SCF(β-TRCP) for subsequent ubiquitination and degradation. As a result, compared to ectopic expression of wild-type NEDD4, introducing a non-degradable NEDD4 (S347A/S348A-NEDD4) promoted cancer cell growth and migration. Hence, our findings revealed the CKI/SCF(β-TRCP) signaling axis as the upstream negative regulator of NEDD4, and further suggested that enhancing NEDD4 degradation, presumably with CKI or SCF(β-TRCP) agonists, could be a promising strategy for treating human cancers.
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Affiliation(s)
- Jia Liu
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Life Science, FIST, Xi'an Jiaotong University, Xi'an, China
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19
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Cukras S, Morffy N, Ohn T, Kee Y. Inactivating UBE2M impacts the DNA damage response and genome integrity involving multiple cullin ligases. PLoS One 2014; 9:e101844. [PMID: 25025768 PMCID: PMC4099125 DOI: 10.1371/journal.pone.0101844] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 06/12/2014] [Indexed: 12/28/2022] Open
Abstract
Protein neddylation is involved in a wide variety of cellular processes. Here we show that the DNA damage response is perturbed in cells inactivated with an E2 Nedd8 conjugating enzyme UBE2M, measured by RAD51 foci formation kinetics and cell based DNA repair assays. UBE2M knockdown increases DNA breakages and cellular sensitivity to DNA damaging agents, further suggesting heightened genomic instability and defective DNA repair activity. Investigating the downstream Cullin targets of UBE2M revealed that silencing of Cullin 1, 2, and 4 ligases incurred significant DNA damage. In particular, UBE2M knockdown, or defective neddylation of Cullin 2, leads to a blockade in the G1 to S progression and is associated with delayed S-phase dependent DNA damage response. Cullin 4 inactivation leads to an aberrantly high DNA damage response that is associated with increased DNA breakages and sensitivity of cells to DNA damaging agents, suggesting a DNA repair defect is associated. siRNA interrogation of key Cullin substrates show that CDT1, p21, and Claspin are involved in elevated DNA damage in the UBE2M knockdown cells. Therefore, UBE2M is required to maintain genome integrity by activating multiple Cullin ligases throughout the cell cycle.
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Affiliation(s)
- Scott Cukras
- Department of Cell Biology, Microbiology, and Molecular Biology, College of Arts and Sciences, University of South Florida, Tampa, Florida, United States of America
| | - Nicholas Morffy
- Department of Cell Biology, Microbiology, and Molecular Biology, College of Arts and Sciences, University of South Florida, Tampa, Florida, United States of America
| | - Takbum Ohn
- Department of Cellular & Molecular Medicine, College of Medicine, Chosun University, Gwangju, Republic of Korea
| | - Younghoon Kee
- Department of Cell Biology, Microbiology, and Molecular Biology, College of Arts and Sciences, University of South Florida, Tampa, Florida, United States of America
- * E-mail:
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20
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Fang L, Choudhary S, Zhao Y, Edeh CB, Yang C, Boldogh I, Brasier AR. ATM regulates NF-κB-dependent immediate-early genes via RelA Ser 276 phosphorylation coupled to CDK9 promoter recruitment. Nucleic Acids Res 2014; 42:8416-32. [PMID: 24957606 PMCID: PMC4117761 DOI: 10.1093/nar/gku529] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Ataxia-telangiectasia mutated (ATM), a member of the phosphatidylinositol 3 kinase-like kinase family, is a master regulator of the double strand DNA break-repair pathway after genotoxic stress. Here, we found ATM serves as an essential regulator of TNF-induced NF-kB pathway. We observed that TNF exposure of cells rapidly induced DNA double strand breaks and activates ATM. TNF-induced ROS promote nuclear IKKγ association with ubiquitin and its complex formation with ATM for nuclear export. Activated cytoplasmic ATM is involved in the selective recruitment of the E3-ubiquitin ligase β-TrCP to phospho-IκBα proteosomal degradation. Importantly, ATM binds and activates the catalytic subunit of protein kinase A (PKAc), ribosmal S6 kinase that controls RelA Ser 276 phosphorylation. In ATM knockdown cells, TNF-induced RelA Ser 276 phosphorylation is significantly decreased. We further observed decreased binding and recruitment of the transcriptional elongation complex containing cyclin dependent kinase-9 (CDK9; a kinase necessary for triggering transcriptional elongation) to promoters of NF-κB-dependent immediate-early cytokine genes, in ATM knockdown cells. We conclude that ATM is a nuclear damage-response signal modulator of TNF-induced NF-κB activation that plays a key scaffolding role in IκBα degradation and RelA Ser 276 phosphorylation. Our study provides a mechanistic explanation of decreased innate immune response associated with A-T mutation.
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Affiliation(s)
- Ling Fang
- Department of Internal Medicine, University of Texas Medical Branch (UTMB), 301 University Blvd, Galveston, TX 77555 USA Department of Biochemistry and Molecular Biology, UTMB, Galveston, TX 77555, USA
| | - Sanjeev Choudhary
- Department of Internal Medicine, University of Texas Medical Branch (UTMB), 301 University Blvd, Galveston, TX 77555 USA Sealy Center for Molecular Medicine, UTMB, 301 University Blvd, Galveston, TX 77555, USA Institute for Translational Sciences, UTMB, 301 University Blvd, Galveston, TX 77555, USA
| | - Yingxin Zhao
- Department of Internal Medicine, University of Texas Medical Branch (UTMB), 301 University Blvd, Galveston, TX 77555 USA Sealy Center for Molecular Medicine, UTMB, 301 University Blvd, Galveston, TX 77555, USA Institute for Translational Sciences, UTMB, 301 University Blvd, Galveston, TX 77555, USA
| | - Chukwudi B Edeh
- Department of Internal Medicine, University of Texas Medical Branch (UTMB), 301 University Blvd, Galveston, TX 77555 USA
| | - Chunying Yang
- Department of Radiation Oncology, Houston Methodist Research Institute, Weill Cornell University, Houston, TX 77030, USA
| | - Istvan Boldogh
- Sealy Center for Molecular Medicine, UTMB, 301 University Blvd, Galveston, TX 77555, USA Department of Microbiology and Immunology, UTMB, 301 University Blvd, Galveston, TX 77555, USA
| | - Allan R Brasier
- Department of Internal Medicine, University of Texas Medical Branch (UTMB), 301 University Blvd, Galveston, TX 77555 USA Sealy Center for Molecular Medicine, UTMB, 301 University Blvd, Galveston, TX 77555, USA Institute for Translational Sciences, UTMB, 301 University Blvd, Galveston, TX 77555, USA
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21
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Zhu G, Fan Z, Ding M, Mu L, Liang J, Ding Y, Fu Y, Huang B, Wu W. DNA damage induces the accumulation of Tiam1 by blocking β-TrCP-dependent degradation. J Biol Chem 2014; 289:15482-94. [PMID: 24737324 DOI: 10.1074/jbc.m114.553388] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The Rac1/JNK cascade plays important roles in DNA damage-induced apoptosis. However, how this cascade is activated upon DNA damage remains to be fully understood. We show here that, in untreated cells, Tiam1, a Rac1-specific guanine nucleotide exchange factor, is phosphorylated by casein kinase 1 (CK1) at its C terminus, leading to Skp, Cullin, F-box-containing(β-TrCP) recognition, ubiquitination, and proteasome-mediated degradation. Upon DNA-damaging anticancer drug treatment, CK1/β-TrCP-mediated Tiam1 degradation is abolished, and the accumulated Tiam1 contributes to downstream activation of Rac1/JNK. Consistently, tumor cells overexpressing Tiam1 are hypersensitive to DNA-damaging drug treatment. In xenograft mice, Tiam1-high cells are more susceptible to doxorubicin treatment. Thus, our results uncover that inhibition of proteasome-mediated Tiam1 degradation is an upstream event leading to Rac1/JNK activation and cell apoptosis in response to DNA-damaging drug treatment.
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Affiliation(s)
- Guixin Zhu
- From the Key Laboratory of Protein Science of Ministry of Education, School of Life Sciences, Tsinghua University, Beijing 100084, China, the Tsinghua-Peking Center for Life Sciences, Beijing 100084, China, and
| | - Zhongyun Fan
- From the Key Laboratory of Protein Science of Ministry of Education, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Miao Ding
- the School of Life Sciences, Peking University, Beijing 100871, China
| | - Libing Mu
- From the Key Laboratory of Protein Science of Ministry of Education, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Juan Liang
- From the Key Laboratory of Protein Science of Ministry of Education, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yajie Ding
- From the Key Laboratory of Protein Science of Ministry of Education, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yu Fu
- From the Key Laboratory of Protein Science of Ministry of Education, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Binlu Huang
- From the Key Laboratory of Protein Science of Ministry of Education, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Wei Wu
- From the Key Laboratory of Protein Science of Ministry of Education, School of Life Sciences, Tsinghua University, Beijing 100084, China,
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22
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Regulation of Mdm2 protein stability and the p53 response by NEDD4-1 E3 ligase. Oncogene 2014; 34:281-9. [PMID: 24413081 DOI: 10.1038/onc.2013.557] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 10/30/2013] [Accepted: 11/22/2013] [Indexed: 01/06/2023]
Abstract
Mdm2 is a critical negative regulator of the tumor suppressor protein p53. Mdm2 is an E3 ligase whose overexpression leads to functional inactivation of p53. Mdm2 protein stability is regulated by several mechanisms including RING (Really Interesting New Gene) domain-mediated autoubiquitination. Here we report biochemical identification of NEDD4-1 as an E3 ligase for Mdm2 that contributes to the regulation of Mdm2 protein stability in cells. NEDD4-1 was identified from Jurkat cytosolic fractions using an enzyme-dead Mdm2 mutant protein as a substrate for in vitro E3 ligase assays. We show that lysates from Nedd4-1 knockout (KO) mouse embryonic fibroblasts (MEFs) have significantly diminished E3 ligase activity toward Mdm2 compared with lysates from wild-type (WT) MEFs. Recombinant NEDD4-1 promotes Mdm2 ubiquitination in vitro in a concentration- and time-dependent manner. In cells, NEDD4-1 physically interacts with Mdm2 via the RING domain of Mdm2. Overexpression of NEDD4-1, but not an enzyme-dead NEDD4-1CS mutant, increases ubiquitination of Mdm2. NEDD4-1 catalyzes the formation of K63-type polyubiquitin chains on Mdm2 that are distinct from K48-type polyubiquitination chains mediated by the Mdm2/MdmX complex. Importantly, K63-type polyubiquitination by NEDD4-1 competes with K48-type polyubiquitination on Mdm2 in cells. As a result, NEDD4-1-mediated ubiquitination stabilizes Mdm2. NEDD4-1 knockdown reduces the t1/2 (half-life) of endogenous Mdm2 from 20 to 12 min in U2OS cells. Nedd4-1 KO MEFs manifest increased p53 levels and activity, a more robust DNA damage response and increased G1 arrest compared with WT MEFs. Similarly, NEDD4-1 knockdown in WT-p53-bearing cells increases basal p53 levels and activity in an Mdm2-dependent manner, causes stronger p53 responses to DNA damage and results in p53-dependent growth inhibition compared with corresponding NEDD4-1-proficient control cells. This study identifies NEDD4-1 as a novel component of the p53/Mdm2 regulatory feedback loop that controls p53 activity during stress responses.
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23
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Ma J, Zhang Q, Chen S, Fang B, Yang Q, Chen C, Miele L, Sarkar FH, Xia J, Wang Z. Mitochondrial dysfunction promotes breast cancer cell migration and invasion through HIF1α accumulation via increased production of reactive oxygen species. PLoS One 2013; 8:e69485. [PMID: 23922721 PMCID: PMC3726697 DOI: 10.1371/journal.pone.0069485] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 06/10/2013] [Indexed: 01/12/2023] Open
Abstract
Although mitochondrial dysfunction has been observed in various types of human cancer cells, the molecular mechanism underlying mitochondrial dysfunction mediated tumorigenesis remains largely elusive. To further explore the function of mitochondria and their involvement in the pathogenic mechanisms of cancer development, mitochondrial dysfunction clones of breast cancer cells were generated by rotenone treatment, a specific inhibitor of mitochondrial electron transport complex I. These clones were verified by mitochondrial respiratory defect measurement. Moreover, those clones exhibited increased reactive oxygen species (ROS), and showed higher migration and invasive behaviors compared with their parental cells. Furthermore, antioxidant N-acetyl cysteine, PEG-catalase, and mito-TEMPO effectively inhibited cell migration and invasion in these clones. Notably, ROS regulated malignant cellular behavior was in part mediated through upregulation of hypoxia-inducible factor-1 α and vascular endothelial growth factor. Our results suggest that mitochondrial dysfunction promotes cancer cell motility partly through HIF1α accumulation mediated via increased production of reactive oxygen species.
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Affiliation(s)
- Jia Ma
- Department of Biochemistry and Molecular Biology, Bengbu Medical College, Bengbu, Anhui, China
| | - Qing Zhang
- Department of Orthopedics, The Center Hospital of Bengbu, Anhui, China
| | - Sulian Chen
- Department of Biochemistry and Molecular Biology, Bengbu Medical College, Bengbu, Anhui, China
| | - Binbin Fang
- Research Center of Clinical Laboratory Science, Bengbu Medical College, Bengbu, Anhui, China
| | - Qingling Yang
- Department of Biochemistry and Molecular Biology, Bengbu Medical College, Bengbu, Anhui, China
| | - Changjie Chen
- Department of Biochemistry and Molecular Biology, Bengbu Medical College, Bengbu, Anhui, China
| | - Lucio Miele
- University of Mississippi Cancer Institute, Jackson, Mississippi, United States of America
| | - Fazlul H. Sarkar
- Department of Pathology and Oncology, Karmanos Cancer Institute, Wayne State University, Detroit, Michigan, United States of America
| | - Jun Xia
- Department of Biochemistry and Molecular Biology, Bengbu Medical College, Bengbu, Anhui, China
- * E-mail: (ZW); (JX)
| | - Zhiwei Wang
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
- Cyrus Tang Hematology Center, Jiangsu Institute of Hematology, First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
- * E-mail: (ZW); (JX)
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24
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Wang C, Xiao H, Ma J, Zhu Y, Yu J, Sun L, Sun H, Liu Y, Jin C, Huang H. The F-box protein β-TrCP promotes ubiquitination of TRF1 and regulates the ALT-associated PML bodies formation in U2OS cells. Biochem Biophys Res Commun 2013; 434:728-34. [DOI: 10.1016/j.bbrc.2013.03.096] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 03/26/2013] [Indexed: 10/26/2022]
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25
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Abstract
UHRF1 (ubiquitin-like, with PHD and RING finger domains 1) is a critical epigenetic player involved in the maintenance of DNA methylation patterns during DNA replication. Dysregulation of the UHRF1 level is implicated in cancer onset, metastasis, and tumor recurrence. Previous studies demonstrated that UHRF1 can be stabilized through USP7-mediated deubiquitylation, but the mechanism through which UHRF1 is ubiquitylated is still unknown. Here we show that proteasomal degradation of UHRF1 is mediated by the SCF(β-TrCP) E3 ligase. Through bioinformatic and mutagenesis studies, we identified a functional DSG degron in the UHRF1 N terminus that is necessary for UHRF1 stability regulation. We further show that UHRF1 physically interacts with β-TrCP1 in a manner dependent on phosphorylation of serine 108 (S108(UHRF1)) within the DSG degron. Furthermore, we demonstrate that S108(UHRF1) phosphorylation is catalyzed by casein kinase 1 delta (CK1δ) and is important for the recognition of UHRF1 by SCF(β-TrCP). Importantly, we demonstrate that UHRF1 degradation is accelerated in response to DNA damage, coincident with enhanced S108(UHRF1) phosphorylation. Taken together, our data identify SCF(β-TrCP) as a bona fide UHRF1 E3 ligase important for regulating UHRF1 steady-state levels both under normal conditions and in response to DNA damage.
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