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Konstantinidou M, Visser EJ, Vandenboorn E, Chen S, Jaishankar P, Overmans M, Dutta S, Neitz RJ, Renslo AR, Ottmann C, Brunsveld L, Arkin MR. Structure-Based Optimization of Covalent, Small-Molecule Stabilizers of the 14-3-3σ/ERα Protein-Protein Interaction from Nonselective Fragments. J Am Chem Soc 2023; 145:20328-20343. [PMID: 37676236 PMCID: PMC10515640 DOI: 10.1021/jacs.3c05161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Indexed: 09/08/2023]
Abstract
The stabilization of protein-protein interactions (PPIs) has emerged as a promising strategy in chemical biology and drug discovery. The identification of suitable starting points for stabilizing native PPIs and their subsequent elaboration into selective and potent molecular glues lacks structure-guided optimization strategies. We have previously identified a disulfide fragment that stabilized the hub protein 14-3-3σ bound to several of its clients, including ERα and C-RAF. Here, we show the structure-based optimization of the nonselective fragment toward selective and highly potent small-molecule stabilizers of the 14-3-3σ/ERα complex. The more elaborated molecular glues, for example, show no stabilization of 14-3-3σ/C-RAF up to 150 μM compound. Orthogonal biophysical assays, including mass spectrometry and fluorescence anisotropy, were used to establish structure-activity relationships. The binding modes of 37 compounds were elucidated with X-ray crystallography, which further assisted the concomitant structure-guided optimization. By targeting specific amino acids in the 14-3-3σ/ERα interface and locking the conformation with a spirocycle, the optimized covalent stabilizer 181 achieved potency, cooperativity, and selectivity similar to the natural product Fusicoccin-A. This case study showcases the value of addressing the structure, kinetics, and cooperativity for molecular glue development.
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Affiliation(s)
- Markella Konstantinidou
- Department
of Pharmaceutical Chemistry and Small Molecule Discovery Center (SMDC), University of California, San Francisco, California 94143, United States
| | - Emira J. Visser
- Laboratory
of Chemical Biology, Department of Biomedical Engineering and Institute
for Complex Molecular Systems (ICMS), Eindhoven
University of Technology, 5600 MB Eindhoven, The Netherlands
| | - Edmee Vandenboorn
- Laboratory
of Chemical Biology, Department of Biomedical Engineering and Institute
for Complex Molecular Systems (ICMS), Eindhoven
University of Technology, 5600 MB Eindhoven, The Netherlands
| | - Sheng Chen
- Department
of Pharmaceutical Chemistry and Small Molecule Discovery Center (SMDC), University of California, San Francisco, California 94143, United States
| | - Priyadarshini Jaishankar
- Department
of Pharmaceutical Chemistry and Small Molecule Discovery Center (SMDC), University of California, San Francisco, California 94143, United States
| | - Maurits Overmans
- Laboratory
of Chemical Biology, Department of Biomedical Engineering and Institute
for Complex Molecular Systems (ICMS), Eindhoven
University of Technology, 5600 MB Eindhoven, The Netherlands
| | - Shubhankar Dutta
- Department
of Pharmaceutical Chemistry and Small Molecule Discovery Center (SMDC), University of California, San Francisco, California 94143, United States
| | - R. Jeffrey Neitz
- Department
of Pharmaceutical Chemistry and Small Molecule Discovery Center (SMDC), University of California, San Francisco, California 94143, United States
| | - Adam R. Renslo
- Department
of Pharmaceutical Chemistry and Small Molecule Discovery Center (SMDC), University of California, San Francisco, California 94143, United States
| | - Christian Ottmann
- Laboratory
of Chemical Biology, Department of Biomedical Engineering and Institute
for Complex Molecular Systems (ICMS), Eindhoven
University of Technology, 5600 MB Eindhoven, The Netherlands
| | - Luc Brunsveld
- Laboratory
of Chemical Biology, Department of Biomedical Engineering and Institute
for Complex Molecular Systems (ICMS), Eindhoven
University of Technology, 5600 MB Eindhoven, The Netherlands
| | - Michelle R. Arkin
- Department
of Pharmaceutical Chemistry and Small Molecule Discovery Center (SMDC), University of California, San Francisco, California 94143, United States
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Accumulation of Fat Not Responsible for Femoral Head Necrosis, Revealed by Single-Cell RNA Sequencing: A Preliminary Study. Biomolecules 2023; 13:biom13010171. [PMID: 36671556 PMCID: PMC9856115 DOI: 10.3390/biom13010171] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 01/09/2023] [Accepted: 01/10/2023] [Indexed: 01/18/2023] Open
Abstract
The etiology of osteonecrosis of the femoral head (ONFH) is not yet fully understood. However, ONFH is a common disease with high morbidity, and approximately one-third of cases are caused by glucocorticoids. We performed single-cell RNA sequencing of bone marrow to explore the effect of glucocorticoid on ONFH. Bone marrow samples of the proximal femur were extracted from four participants during total hip arthroplasty, including two participants diagnosed with ONFH for systemic lupus erythematosus (SLE) treated with glucocorticoids (the case group) and two participants with femoral neck fracture (the control group). Unbiased transcriptome-wide single-cell RNA sequencing analysis and computational analyses were performed. Seventeen molecularly defined cell types were identified in the studied samples, including significantly dysregulated neutrophils and B cells in the case group. Additionally, fatty acid synthesis and aerobic oxidation were repressed, while fatty acid beta-oxidation was enhanced. Our results also preliminarily clarified the roles of the inflammatory response, substance metabolism, vascular injury, angiogenesis, cell proliferation, apoptosis, and dysregulated coagulation and fibrinolysis in glucocorticoid-induced ONFH. Notably, we list the pathways that were markedly altered in glucocorticoid-induced ONFH with SLE compared with femoral head fracture, as well as their common genes, which are potential early therapeutic targets. Our results provide new insights into the mechanism of glucocorticoid-induced ONFH and present potential clues for effective and functional manipulation of human glucocorticoid-induced ONFH, which could improve patient outcomes.
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Kim HJ, Seo BG, Seo EC, Lee KM, Hwangbo C. Checkpoint Kinase 1 (CHK1) Functions as Both a Diagnostic Marker and a Regulator of Epithelial-to-Mesenchymal Transition (EMT) in Triple-Negative Breast Cancer. Curr Issues Mol Biol 2022; 44:5848-5865. [PMID: 36547059 PMCID: PMC9777496 DOI: 10.3390/cimb44120398] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/17/2022] [Accepted: 11/19/2022] [Indexed: 11/25/2022] Open
Abstract
Triple-negative breast cancer (TNBC) is more difficult to treat and has a higher mortality rate than other subtypes. Although hormone receptor-targeted therapy is an effective treatment to increase survival rate in breast cancer patients, it is not suitable for TNBC patients. To address the issues, differentially expressed genes (DEGs) in TNBC patients from the Gene Expression Omnibus (GEO) database were analyzed. A total of 170 genes were obtained from three Genomic Spatial Events (GSEs) using the intersection of each GSE dataset and 61 DEGs were identified after validation with the gene enrichment analysis. We combined this with the degree scores from the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and protein-protein interaction (PPI) network, of which 7 genes were correlated with survival rate. Finally, a proteomics database revealed that only the CHK1 protein level was differently expressed in basal-like compared with other subtypes. We demonstrated that CHK1 expression was higher in TNBC cell lines compared with non-TNBC cell lines, and CHK1 promotes epithelial to mesenchymal transition (EMT) as well as migration and invasion ability. Our study provides new insight into the TNBC subnetwork that may be useful in the prognosis and treatment of TNBC patients.
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Affiliation(s)
- Hyo-Jin Kim
- Division of Life Science, College of Natural Sciences, Gyeongsang National University, Jinju 52828, Republic of Korea
- Division of Applied Life Science (BK21 Four), PMBBRC and Research Institute of Life Sciences, Geongsang National University, Jinju 52828, Republic of Korea
- Correspondence: (H.-J.K.); (C.H.)
| | - Bo-Gyeong Seo
- Division of Life Science, College of Natural Sciences, Gyeongsang National University, Jinju 52828, Republic of Korea
- Division of Applied Life Science (BK21 Four), PMBBRC and Research Institute of Life Sciences, Geongsang National University, Jinju 52828, Republic of Korea
| | - Eun-Chan Seo
- Division of Life Science, College of Natural Sciences, Gyeongsang National University, Jinju 52828, Republic of Korea
- Division of Applied Life Science (BK21 Four), PMBBRC and Research Institute of Life Sciences, Geongsang National University, Jinju 52828, Republic of Korea
| | - Kwang-Min Lee
- Division of Life Science, College of Natural Sciences, Gyeongsang National University, Jinju 52828, Republic of Korea
- Division of Applied Life Science (BK21 Four), PMBBRC and Research Institute of Life Sciences, Geongsang National University, Jinju 52828, Republic of Korea
| | - Cheol Hwangbo
- Division of Life Science, College of Natural Sciences, Gyeongsang National University, Jinju 52828, Republic of Korea
- Division of Applied Life Science (BK21 Four), PMBBRC and Research Institute of Life Sciences, Geongsang National University, Jinju 52828, Republic of Korea
- Correspondence: (H.-J.K.); (C.H.)
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Brown DW, Beatty PH, Lewis JD. Molecular Targeting of the Most Functionally Complex Gene in Precision Oncology: p53. Cancers (Basel) 2022; 14:5176. [PMID: 36358595 PMCID: PMC9654076 DOI: 10.3390/cancers14215176] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 10/16/2022] [Accepted: 10/20/2022] [Indexed: 09/29/2023] Open
Abstract
While chemotherapy is a key treatment strategy for many solid tumors, it is rarely curative, and most tumor cells eventually become resistant. Because of this, there is an unmet need to develop systemic treatments that capitalize on the unique mutational landscape of each patient's tumor. The most frequently mutated protein in cancer, p53, has a role in nearly all cancer subtypes and tumorigenesis stages and therefore is one of the most promising molecular targets for cancer treatment. Unfortunately, drugs targeting p53 have seen little clinical success despite promising preclinical data. Most of these drug compounds target specific aspects of p53 inactivation, such as through inhibiting negative regulation by the mouse double minute (MDM) family of proteins. These treatment strategies fail to address cancer cells' adaptation mechanisms and ignore the impact that p53 loss has on the entire p53 network. However, recent gene therapy successes show that targeting the p53 network and cellular dysfunction caused by p53 inactivation is now possible and may soon translate into successful clinical responses. In this review, we discuss p53 signaling complexities in cancer that have hindered the development and use of p53-targeted drugs. We also describe several current therapeutics reporting promising preclinical and clinical results.
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Affiliation(s)
- Douglas W. Brown
- Department of Oncology, University of Alberta, Edmonton, AB T6G 2E1, Canada
- Entos Pharmaceuticals, Unit 4550, 10230 Jasper Avenue, Edmonton, AB T5J 4P6, Canada
| | - Perrin H. Beatty
- Entos Pharmaceuticals, Unit 4550, 10230 Jasper Avenue, Edmonton, AB T5J 4P6, Canada
| | - John D. Lewis
- Department of Oncology, University of Alberta, Edmonton, AB T6G 2E1, Canada
- Entos Pharmaceuticals, Unit 4550, 10230 Jasper Avenue, Edmonton, AB T5J 4P6, Canada
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Srdanović S, Wolter M, Trinh CH, Ottmann C, Warriner SL, Wilson AJ. Understanding the interaction of 14-3-3 proteins with hDMX and hDM2: a structural and biophysical study. FEBS J 2022; 289:5341-5358. [PMID: 35286747 PMCID: PMC9541495 DOI: 10.1111/febs.16433] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 02/11/2022] [Accepted: 03/11/2022] [Indexed: 01/06/2023]
Abstract
p53 plays a critical role in regulating diverse biological processes: DNA repair, cell cycle arrest, apoptosis and senescence. The p53 pathway has therefore served as the focus of multiple drug-discovery efforts. p53 is negatively regulated by hDMX and hDM2; prior studies have identified 14-3-3 proteins as hDMX and hDM2 client proteins. 14-3-3 proteins are adaptor proteins that modulate localization, degradation and interactions of their targets in response to phosphorylation. Thus, 14-3-3 proteins may indirectly modulate the interaction between hDMX or hDM2 and p53 and represent potential targets for modulation of the p53 pathway. In this manuscript, we report on the biophysical and structural characterization of peptide/protein interactions that are representative of the interaction between 14-3-3 and hDMX or hDM2. The data establish that proximal phosphosites spaced ~20-25 residues apart in both hDMX and hDM2 co-operate to facilitate high-affinity 14-3-3 binding and provide structural insight that can be utilized in future stabilizer/inhibitor discovery efforts.
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Affiliation(s)
- Sonja Srdanović
- Astbury Centre for Structural Molecular BiologyUniversity of LeedsUK,School of ChemistryUniversity of LeedsUK
| | - Madita Wolter
- Laboratory of Chemical BiologyDepartment of Biomedical EngineeringTechnische Universiteit EindhovenThe Netherlands,Institute for Complex Molecular SystemsTechnische Universiteit EindhovenThe Netherlands
| | - Chi H. Trinh
- Astbury Centre for Structural Molecular BiologyUniversity of LeedsUK,School of Molecular and Cellular BiologyUniversity of LeedsUK
| | - Christian Ottmann
- Laboratory of Chemical BiologyDepartment of Biomedical EngineeringTechnische Universiteit EindhovenThe Netherlands,Institute for Complex Molecular SystemsTechnische Universiteit EindhovenThe Netherlands
| | - Stuart L. Warriner
- Astbury Centre for Structural Molecular BiologyUniversity of LeedsUK,School of ChemistryUniversity of LeedsUK
| | - Andrew J. Wilson
- Astbury Centre for Structural Molecular BiologyUniversity of LeedsUK,School of ChemistryUniversity of LeedsUK
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Sanford JD, Yang J, Han J, Tollini LA, Jin A, Zhang Y. MDMX is essential for the regulation of p53 protein levels in the absence of a functional MDM2 C-terminal tail. BMC Mol Cell Biol 2021; 22:46. [PMID: 34551723 PMCID: PMC8459461 DOI: 10.1186/s12860-021-00385-3] [Citation(s) in RCA: 2] [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: 01/27/2021] [Accepted: 08/20/2021] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND MDM2 is an E3 ubiquitin ligase that is able to ubiquitinate p53, targeting it for proteasomal degradation. Its homologue MDMX does not have innate E3 activity, but is able to dimerize with MDM2. Although mouse models have demonstrated both MDM2 and MDMX are individually essential for p53 regulation, the significance of MDM2-MDMX heterodimerization is only partially understood and sometimes controversial. MDM2C462A mice, where the C462A mutation abolishes MDM2 E3 ligase activity as well as its ability to dimerize with MDMX, die during embryogenesis. In contrast, the MDM2Y487A mice, where the Y487A mutation at MDM2 C-terminus significantly reduces its E3 ligase activity without disrupting MDM2-MDMX binding, survive normally even though p53 is expressed to high levels. This indicates that the MDM2-MDMX heterodimerization plays a critical role in the regulation of p53. However, it remains unclear whether MDMX is essential for the regulation of p53 protein levels in the context of an endogenous MDM2 C-terminal tail mutation. RESULTS Here, we studied the significance of MDM2-MDMX binding in an MDM2 E3 ligase deficient context using the MDM2Y487A mouse embryonic fibroblast (MEF) cells. Surprisingly, down-regulation of MDMX in MDM2Y487A MEFs resulted in a significant increase of p53 protein levels. Conversely, ectopic overexpression of MDMX reduced p53 protein levels in MDM2Y487A MEFs. Mutations of the RING domain of MDMX prevented MDMX-MDM2 binding, and ablated MDMX-mediated suppression of p53 protein expression. Additionally, DNA damage treatment and nuclear sequestration of MDMX inhibited MDMX activity to suppress p53 protein expression. CONCLUSIONS These results suggest that MDMX plays a key role in suppressing p53 protein expression in the absence of normal MDM2 E3 ligase activity. We found that the ability of MDMX to suppress p53 levels requires MDM2 binding and its cytoplasmic localization, and this ability is abrogated by DNA damage. Hence, MDMX is essential for the regulation of p53 protein levels in the context of an MDM2 C-terminal mutation that disrupts its E3 ligase activity but not MDMX binding. Our study is the first to examine the role of MDMX in the regulation of p53 in the context of endogenous MDM2 C-terminal mutant MEF cells.
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Affiliation(s)
- Jack D Sanford
- Department of Radiation Oncology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27514, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27514, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27514, USA
| | - Jing Yang
- Department of Radiation Oncology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27514, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27514, USA
- Jiangsu Province Key Laboratory of Immunity and Metabolism and Department of Pathogenic Biology and Immunology, Xuzhou Medical University, Xuzhou, 221002, Jiangsu, China
| | - Jing Han
- Department of Radiation Oncology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27514, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27514, USA
- Jiangsu Province Key Laboratory of Immunity and Metabolism and Department of Pathogenic Biology and Immunology, Xuzhou Medical University, Xuzhou, 221002, Jiangsu, China
| | - Laura A Tollini
- Department of Radiation Oncology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27514, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27514, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27514, USA
| | - Aiwen Jin
- Department of Radiation Oncology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27514, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27514, USA
| | - Yanping Zhang
- Department of Radiation Oncology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27514, USA.
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27514, USA.
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27514, USA.
- Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27514, USA.
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Role of Dietary Antioxidants in p53-Mediated Cancer Chemoprevention and Tumor Suppression. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:9924328. [PMID: 34257824 PMCID: PMC8257365 DOI: 10.1155/2021/9924328] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 05/31/2021] [Indexed: 02/07/2023]
Abstract
Cancer arises through a complex interplay between genetic, behavioral, metabolic, and environmental factors that combined trigger cellular changes that over time promote malignancy. In terms of cancer prevention, behavioral interventions such as diet can promote genetic programs that may facilitate tumor suppression; and one of the key tumor suppressors responsible for initiating such programs is p53. The p53 protein is activated by various cellular events such as DNA damage, hypoxia, heat shock, and overexpression of oncogenes. Due to its role in cell fate decisions after DNA damage, regulatory pathways controlled by p53 help to maintain genome stability and thus “guard the genome” against mutations that cause cancer. Dietary intake of flavonoids, a C15 group of polyphenols, is known to inhibit cancer progression and assist DNA repair through p53-mediated mechanisms in human cells via their antioxidant activities. For example, quercetin arrests human cervical cancer cell growth by blocking the G2/M phase cell cycle and inducing mitochondrial apoptosis through a p53-dependent mechanism. Other polyphenols such as resveratrol upregulate p53 expression in several cancer cell lines by promoting p53 stability, which in colon cancer cells results in the activation of p53-mediated apoptosis. Finally, among vitamins, folic acid seems to play an important role in the chemoprevention of gastric carcinogenesis by enhancing gastric epithelial apoptosis in patients with premalignant lesions by significantly increased expression of p53. In this review, we discuss the role of these and other dietary antioxidants in p53-mediated cell signaling in relation to cancer chemoprevention and tumor suppression in normal and cancer cells.
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Jia P, Manuel AM, Fernandes BS, Dai Y, Zhao Z. Distinct effect of prenatal and postnatal brain expression across 20 brain disorders and anthropometric social traits: a systematic study of spatiotemporal modularity. Brief Bioinform 2021; 22:6291943. [PMID: 34086851 DOI: 10.1093/bib/bbab214] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/30/2021] [Accepted: 05/15/2021] [Indexed: 02/06/2023] Open
Abstract
Different spatiotemporal abnormalities have been implicated in different neuropsychiatric disorders and anthropometric social traits, yet an investigation in the temporal network modularity with brain tissue transcriptomics has been lacking. We developed a supervised network approach to investigate the genome-wide association study (GWAS) results in the spatial and temporal contexts and demonstrated it in 20 brain disorders and anthropometric social traits. BrainSpan transcriptome profiles were used to discover significant modules enriched with trait susceptibility genes in a developmental stage-stratified manner. We investigated whether, and in which developmental stages, GWAS-implicated genes are coordinately expressed in brain transcriptome. We identified significant network modules for each disorder and trait at different developmental stages, providing a systematic view of network modularity at specific developmental stages for a myriad of brain disorders and traits. Specifically, we observed a strong pattern of the fetal origin for most psychiatric disorders and traits [such as schizophrenia (SCZ), bipolar disorder, obsessive-compulsive disorder and neuroticism], whereas increased co-expression activities of genes were more strongly associated with neurological diseases [such as Alzheimer's disease (AD) and amyotrophic lateral sclerosis] and anthropometric traits (such as college completion, education and subjective well-being) in postnatal brains. Further analyses revealed enriched cell types and functional features that were supported and corroborated prior knowledge in specific brain disorders, such as clathrin-mediated endocytosis in AD, myelin sheath in multiple sclerosis and regulation of synaptic plasticity in both college completion and education. Our study provides a landscape view of the spatiotemporal features in a myriad of brain-related disorders and traits.
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Affiliation(s)
- Peilin Jia
- Center for Precision Health, School of Biomedical Informatics, the University of Texas Health Science Center at Houston, 7000 Fannin St. Suite 600, Houston, TX 77030, USA
| | - Astrid M Manuel
- Center for Precision Health, School of Biomedical Informatics, the University of Texas Health Science Center at Houston, 7000 Fannin St. Suite 600, Houston, TX 77030, USA
| | - Brisa S Fernandes
- Center for Precision Health, School of Biomedical Informatics, the University of Texas Health Science Center at Houston, 7000 Fannin St. Suite 600, Houston, TX 77030, USA
| | - Yulin Dai
- Center for Precision Health, School of Biomedical Informatics, the University of Texas Health Science Center at Houston, 7000 Fannin St. Suite 600, Houston, TX 77030, USA
| | - Zhongming Zhao
- Center for Precision Health, School of Biomedical Informatics, the University of Texas Health Science Center at Houston, 7000 Fannin St. Suite 600, Houston, TX 77030, USA
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Falcicchio M, Ward JA, Macip S, Doveston RG. Regulation of p53 by the 14-3-3 protein interaction network: new opportunities for drug discovery in cancer. Cell Death Discov 2020; 6:126. [PMID: 33298896 PMCID: PMC7669891 DOI: 10.1038/s41420-020-00362-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 10/02/2020] [Accepted: 10/23/2020] [Indexed: 01/17/2023] Open
Abstract
Most cancers evolve to disable the p53 pathway, a key tumour suppressor mechanism that prevents transformation and malignant cell growth. However, only ~50% exhibit inactivating mutations of p53, while in the rest its activity is suppressed by changes in the proteins that modulate the pathway. Therefore, restoring p53 activity in cells in which it is still wild type is a highly attractive therapeutic strategy that could be effective in many different cancer types. To this end, drugs can be used to stabilise p53 levels by modulating its regulatory pathways. However, despite the emergence of promising strategies, drug development has stalled in clinical trials. The need for alternative approaches has shifted the spotlight to the 14-3-3 family of proteins, which strongly influence p53 stability and transcriptional activity through direct and indirect interactions. Here, we present the first detailed review of how 14-3-3 proteins regulate p53, with special emphasis on the mechanisms involved in their binding to different members of the pathway. This information will be important to design new compounds that can reactivate p53 in cancer cells by influencing protein-protein interactions. The intricate relationship between the 14-3-3 isoforms and the p53 pathway suggests that many potential drug targets for p53 reactivation could be identified and exploited to design novel antineoplastic therapies with a wide range of applications.
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Affiliation(s)
- Marta Falcicchio
- Leicester Institute for Structural and Chemical Biology, University of Leicester, University Road, Leicester, LE1 7RH, UK
- School of Chemistry, University of Leicester, University Road, Leicester, LE1 7RH, UK
| | - Jake A Ward
- Leicester Institute for Structural and Chemical Biology, University of Leicester, University Road, Leicester, LE1 7RH, UK
- Mechanisms of Cancer and Ageing Lab, Department of Molecular and Cell Biology, University of Leicester, University Road, Leicester, LE1 7RH, UK
| | - Salvador Macip
- Mechanisms of Cancer and Ageing Lab, Department of Molecular and Cell Biology, University of Leicester, University Road, Leicester, LE1 7RH, UK.
- FoodLab, Faculty of Health Sciences, Universitat Oberta de Catalunya, Barcelona, Spain.
| | - Richard G Doveston
- Leicester Institute for Structural and Chemical Biology, University of Leicester, University Road, Leicester, LE1 7RH, UK.
- School of Chemistry, University of Leicester, University Road, Leicester, LE1 7RH, UK.
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10
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Abstract
14-3-3 proteins are mostly expressed in the brain and are closely involved in numerous brain functions and various brain disorders. Among the isotypes of the 14-3-3 proteins, 14-3-3γ is mainly expressed in neurons and is highly produced during brain development, which could indicate that it has a significance in neural development. Furthermore, the distinctive levels of temporally and locally regulated 14-3-3γ expression in various brain disorders suggest that it could play a substantial role in brain plasticity of the diseased states. In this review, we introduce the various brain disorders reported to be involved with 14-3-3γ, and summarize the changes of 14-3-3γ expression in each brain disease. We also discuss the potential of 14-3-3γ for treatment and the importance of research on specific 14-3-3 isotypes for an effective therapeutic approach.
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Affiliation(s)
- Eunsil Cho
- School of Biosystem and Biomedical Science, College of Health Science, Korea University, Seoul 02708, Korea
| | - Jae-Yong Park
- School of Biosystem and Biomedical Science, College of Health Science, Korea University, Seoul 02708, Korea
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11
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Norouzi S, Yazdian Robati R, Ghandadi M, Abnous K, Behravan J, Mosaffa F. Comparative proteomics study of proteins involved in induction of higher rates of cell death in mitoxantrone-resistant breast cancer cells MCF-7/MX exposed to TNF-α. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2020; 23:663-672. [PMID: 32742605 PMCID: PMC7374993 DOI: 10.22038/ijbms.2020.40029.9486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Objective(s): Resistance to medications is one of the main complications in chemotherapy of cancer. It has been shown that some multidrug resistant cancer cells indicate more sensitivity against cytotoxic effects of TNF-α compared to their parental cells. Our previous findings indicated vulnerability of the mitoxantrone-resistant breast cancer cells MCF-7/MX to cell death induced by TNF-α compared to the parent cells MCF-7. In this study, we performed a comparative proteomics analysis for identification of proteins involved in induction of higher susceptibility of MCF-7/MX cells to cytotoxic effect of TNF-α. Materials and Methods: Intensity of protein spots in 2D gel electrophoresis profiles of MCF-7 and MCF-7/MX cells were compared with Image Master Platinum 6.0 software. Selected differential protein-spots were identified with MALDI-TOF/TOF mass spectrometry and database searching. Pathway analyses of identified proteins were performed using PANTHER, KEGG PATHWAY, Gene MANIA and STRING databases. Western blot was performed for confirmation of the proteomics results. Results: Our results indicated that 48 hr exposure to TNF-α induced 87% death in MCF-7/MX cells compared to 19% death in MCF-7 cells. Forty landmarks per 2D gel electrophoresis were matched by Image Master Software. Six proteins were identified with mass spectrometry. Western blot showed that 14-3-3γ and p53 proteins were expressed higher in MCF-7/MX cells treated with TNF-α compared to MCF-7 cells treated with TNF-α. Conclusion: Our results showed that 14-3-3 γ, prohibitin, peroxiredoxin 2 and P53 proteins which were expressed differentially in MCF-7/MX cells treated with TNF-α may involve in the induction of higher rates of cell death in these cells compared to TNF-α-treated MCF-7 cells.
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Affiliation(s)
- Saeed Norouzi
- Department of Pharmaceutical Biotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Rezvan Yazdian Robati
- Molecular and Cell Biology Research Center, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - Morteza Ghandadi
- Pharmaceutical Sciences Research Center, Mazandaran University of Medical Sciences, Sari, Iran.,Department of Pharmacognosy and Pharmaceutical Biotechnology, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
| | - Khalil Abnous
- Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Javad Behravan
- School of Pharmacy, University of Waterloo, Waterloo, Ontario, Canada.,Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Fatemeh Mosaffa
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran.,Department of Pharmaceutical Biotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
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12
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Haupt S, Mejía-Hernández JO, Vijayakumaran R, Keam SP, Haupt Y. The long and the short of it: the MDM4 tail so far. J Mol Cell Biol 2020; 11:231-244. [PMID: 30689920 PMCID: PMC6478121 DOI: 10.1093/jmcb/mjz007] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 12/16/2018] [Accepted: 01/21/2019] [Indexed: 12/27/2022] Open
Abstract
The mouse double minute 4 (MDM4) is emerging from the shadow of its more famous relative MDM2 and is starting to steal the limelight, largely due to its therapeutic possibilities. MDM4 is a vital regulator of the tumor suppressor p53. It restricts p53 transcriptional activity and also, at least in development, facilitates MDM2's E3 ligase activity toward p53. These functions of MDM4 are critical for normal cell function and a proper response to stress. Their importance for proper cell maintenance and proliferation identifies them as a risk for deregulation associated with the uncontrolled growth of cancer. MDM4 tails are vital for its function, where its N-terminus transactivation domain engages p53 and its C-terminus RING domain binds to MDM2. In this review, we highlight recently identified cellular functions of MDM4 and survey emerging therapies directed to correcting its dysregulation in disease.
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Affiliation(s)
- Sue Haupt
- Tumor Suppression Laboratory, Peter MacCallum Cancer Centre, 305 Grattan Street, Melbourne, Victoria, Australia.,Department of Clinical Pathology, The University of Melbourne, Parkville, Victoria, Australia
| | | | - Reshma Vijayakumaran
- Tumor Suppression Laboratory, Peter MacCallum Cancer Centre, 305 Grattan Street, Melbourne, Victoria, Australia
| | - Simon P Keam
- Tumor Suppression Laboratory, Peter MacCallum Cancer Centre, 305 Grattan Street, Melbourne, Victoria, Australia
| | - Ygal Haupt
- Tumor Suppression Laboratory, Peter MacCallum Cancer Centre, 305 Grattan Street, Melbourne, Victoria, Australia.,Department of Clinical Pathology, The University of Melbourne, Parkville, Victoria, Australia.,Department of Biochemistry and Molecular Biology, Monash University, Clayton Campus, Victoria, Australia.,Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, Victoria, Australia
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13
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Dobbelstein M, Levine AJ. Mdm2: Open questions. Cancer Sci 2020; 111:2203-2211. [PMID: 32335977 PMCID: PMC7385351 DOI: 10.1111/cas.14433] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 04/16/2020] [Accepted: 04/18/2020] [Indexed: 12/16/2022] Open
Abstract
The Mdm2 oncoprotein and its association with p53 were discovered 30 years ago, and a cornucopia of activities and regulatory pathways have been associated with it. In this review, we will raise questions about Mdm2 and its cousin Mdm4 that we consider worth pursuing in future research, reaching from molecular structures and intracellular activities all the way to development, evolution, and cancer therapy. We anticipate that such research will not only close a few gaps in our knowledge but could add new dimensions to our current view. This compilation of questions contributes to the preparation for the 10th Mdm2 Workshop in Tokyo.
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Affiliation(s)
- Matthias Dobbelstein
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, Göttingen, Germany
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14
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Xia Y, Wang L, Ma X, Li X. Investigation on the Genomic Characterization of Uterine Sarcoma for rAd- p53 Combined with Chemotherapy Treatment. Hum Gene Ther 2020; 31:881-890. [PMID: 32013587 DOI: 10.1089/hum.2019.305] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The aim is to investigate the genomic characterization of uterine sarcoma for rAd-p53 (Gendicine®) combined with chemotherapy treatment. We recently published an article on 12 cases of uterine sarcomas, which were treated with rAd-p53 combined with chemotherapy. We found that rAd-p53 combined with chemotherapy is effective for various uterine sarcomas. Pretreatment pathological specimens of four uterine sarcoma patients were collected from the above recent clinical research and numbered 1-4A/B. Tumor samples were subjected to targeted sequencing by using a 416 genes panel. We profiled the mutation spectrum and tumor mutation burden in the tumors, identified mutated genes, and explored their gene function. We also verified the p53 protein expression using immunohistochemistry. We identified a total of 30 mutated genes that were found from the next-generation sequencing test results. The average number of mutated genes was up to seven in the five samples. TP53 gene was mutated in two of the four patients, No. 1 and No. 4B. They are c.C833G (p.P278R) missense mutation and a point mutation (C141*) that result in a premature stop codon. We did not find a mutated TP53 gene in the other two cases, but we identified mutated genes, including CREBBP, LYN, CDKN2A, and JAK2, which were located upstream of the TP53 gene; they may have an impact on TP53. We also identified 11 additional genes which are involved in p53-related signaling pathways or have interaction with p53. Compared to solid tumor mutational burden (TMB) distribution, none of their TMB was ranking in the top 25%. Mutant p53 protein expression was positive in two specimens. Our results demonstrated that the TP53 signaling pathway plays an important role in uterine sarcoma tumorigenesis. TP53 and the upstream genes such as CREBBP, LYN, CDKN2A, and JAK2 may be involved in the genomic characterization for rAd-p53 (Gendicine) combined with chemotherapy in uterine sarcoma. Besides, the average amount of mutated genes from every patient is large.
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Affiliation(s)
- Yu Xia
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Lei Wang
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Xiaolin Ma
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Xiuqin Li
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, China
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15
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Yao L, Yu F, Xu Y, Wang Y, Zuo Y, Wang C, Ye L. DNA damage response manages cell cycle restriction of senile multipotent mesenchymal stromal cells. Mol Biol Rep 2019; 47:809-818. [PMID: 31664596 DOI: 10.1007/s11033-019-05150-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 10/18/2019] [Indexed: 02/05/2023]
Abstract
Multipotent mesenchymal stromal cells (MMSCs) are promising to treat a variety of traumatic and degenerative diseases. However, in vitro-passage aging induces cell cycle arrest and a series of genetic and biological changes, which greatly limits ex vivo cell number expansion and further clinical application of MMSCs. In most cases, DNA damage and DNA damage response (DDR) act as the main cause and executor of cellular senescence respectively. Mechanistically, DNA damage signals induce cell cycle arrest and DNA damage repair via DDR. If the DNA damage is indelible, MMSCs would entry into a permanent cell cycle arrest. It should be noted that apart from DDR signaling, certain proliferation or metabolism pathways are also occupied in DNA damage related cell cycle arrest. New findings of these aspects will also be summarized in this study. In summary, we aim to provide a comprehensive review of DDR associated cell cycle regulation and other major molecular signaling in the senescence of MMSCs. Above knowledge could contribute to improve the limited capacity of in vitro expansion of MMSCs, and then promote their clinical applications.
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Affiliation(s)
- Lin Yao
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Fanyuan Yu
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yining Xu
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yitian Wang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yanqin Zuo
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Chenglin Wang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Ling Ye
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China. .,Department of Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
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16
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Reed KM, Mendoza KM, Coulombe RA. Altered Gene Response to Aflatoxin B 1 in the Spleens of Susceptible and Resistant Turkeys. Toxins (Basel) 2019; 11:toxins11050242. [PMID: 31035349 PMCID: PMC6562755 DOI: 10.3390/toxins11050242] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 04/22/2019] [Accepted: 04/27/2019] [Indexed: 12/21/2022] Open
Abstract
Susceptibility and/or resistance to aflatoxin B1 (AFB1) is a threshold trait governed principally by glutathione S transferase (GST)-mediated detoxification. In poultry, domesticated turkeys are highly sensitive to AFB1, most likely due to dysfunction in hepatic GSTs. In contrast, wild turkeys are comparatively resistant to aflatoxicosis due to the presence of functional hepatic GSTAs and other possible physiological and immunological interactions. The underlying genetic basis for the disparate GST function in turkeys is unknown as are the broader molecular interactions that control the systemic response. This study quantifies the effects of dietary AFB1 on gene expression in the turkey spleen, specifically contrasting genetically distinct domesticated (DT, susceptible) and Eastern wild (EW, resistant) birds. Male turkey poults were subjected to a short-term AFB1 treatment protocol with feed supplemented with 320 ppb AFB1 beginning on day 15 of age and continuing for 14 days. Spleen tissues were harvested and subjected to deep RNA sequencing and transcriptome analysis. Analysis of differential gene expression found the effects of AFB1 treatment on the spleen transcriptomes considerably more prominent in the DT birds compared to EW. However, expression of the differentially expressed genes (DEGs) was directionally biased, with the majority showing higher expression in EW (i.e., down-regulation in DT). Significantly altered pathways included FXR/RXR and LXR/RXR activation, coagulation system, prothrombin activation, acute phase response, and atherosclerosis signaling. Differential extra-hepatic expression of acute phase protein genes was confirmed by quantitative real time PCR (qRT-PCR) in the original experiment and additional turkey lines. Results demonstrate that wild turkeys possess a capacity to more effectively respond to AFB1 exposure.
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Affiliation(s)
- Kent M Reed
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN 55108, USA.
| | - Kristelle M Mendoza
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN 55108, USA.
| | - Roger A Coulombe
- Department of Animal, Dairy and Veterinary Sciences, College of Agriculture, Utah State University, Logan, UT 84322, USA.
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17
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Pennington KL, Chan TY, Torres MP, Andersen JL. The dynamic and stress-adaptive signaling hub of 14-3-3: emerging mechanisms of regulation and context-dependent protein-protein interactions. Oncogene 2018; 37:5587-5604. [PMID: 29915393 PMCID: PMC6193947 DOI: 10.1038/s41388-018-0348-3] [Citation(s) in RCA: 218] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 05/07/2018] [Accepted: 05/07/2018] [Indexed: 12/14/2022]
Abstract
14-3-3 proteins are a family of structurally similar phospho-binding proteins that regulate essentially every major cellular function. Decades of research on 14-3-3s have revealed a remarkable network of interacting proteins that demonstrate how 14-3-3s integrate and control multiple signaling pathways. In particular, these interactions place 14-3-3 at the center of the signaling hub that governs critical processes in cancer, including apoptosis, cell cycle progression, autophagy, glucose metabolism, and cell motility. Historically, the majority of 14-3-3 interactions have been identified and studied under nutrient-replete cell culture conditions, which has revealed important nutrient driven interactions. However, this underestimates the reach of 14-3-3s. Indeed, the loss of nutrients, growth factors, or changes in other environmental conditions (e.g., genotoxic stress) will not only lead to the loss of homeostatic 14-3-3 interactions, but also trigger new interactions, many of which are likely stress adaptive. This dynamic nature of the 14-3-3 interactome is beginning to come into focus as advancements in mass spectrometry are helping to probe deeper and identify context-dependent 14-3-3 interactions-providing a window into adaptive phosphorylation-driven cellular mechanisms that orchestrate the tumor cell's response to a variety of environmental conditions including hypoxia and chemotherapy. In this review, we discuss emerging 14-3-3 regulatory mechanisms with a focus on post-translational regulation of 14-3-3 and dynamic protein-protein interactions that illustrate 14-3-3's role as a stress-adaptive signaling hub in cancer.
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Affiliation(s)
- K L Pennington
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA
| | - T Y Chan
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA
| | - M P Torres
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - J L Andersen
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA.
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18
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Gerber KJ, Squires KE, Hepler JR. 14-3-3γ binds regulator of G protein signaling 14 (RGS14) at distinct sites to inhibit the RGS14:Gα i-AlF 4- signaling complex and RGS14 nuclear localization. J Biol Chem 2018; 293:14616-14631. [PMID: 30093406 DOI: 10.1074/jbc.ra118.002816] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 07/23/2018] [Indexed: 11/06/2022] Open
Abstract
Regulator of G protein signaling 14 (RGS14) is a multifunctional brain scaffolding protein that integrates G protein and Ras/ERK signaling pathways. It is also a nucleocytoplasmic shuttling protein. RGS14 binds active Gαi/o via its RGS domain, Raf and active H-Ras-GTP via its R1 Ras-binding domain (RBD), and inactive Gαi1/3 via its G protein regulatory (GPR) domain. RGS14 suppresses long-term potentiation (LTP) in the CA2 region of the hippocampus, thereby regulating hippocampally based learning and memory. The 14-3-3 family of proteins is necessary for hippocampal LTP and associative learning and memory. Here, we show direct interaction between RGS14 and 14-3-3γ at two distinct sties, one phosphorylation-independent and the other phosphorylation-dependent at Ser-218 that is markedly potentiated by signaling downstream of active H-Ras. Using bioluminescence resonance energy transfer (BRET), we show that the pSer-218-dependent RGS14/14-3-3γ interaction inhibits active Gαi1-AlF4- binding to the RGS domain of RGS14 but has no effect on active H-Ras and inactive Gαi1-GDP binding to RGS14. By contrast, the phosphorylation-independent binding of 14-3-3 has no effect on RGS14/Gαi interactions but, instead, inhibits (directly or indirectly) RGS14 nuclear import and nucleocytoplasmic shuttling. Together, our findings describe a novel mechanism of negative regulation of RGS14 functions, specifically interactions with active Gαi and nuclear import, while leaving the function of other RGS14 domains intact. Ongoing studies will further elucidate the physiological function of this interaction between RGS14 and 14-3-3γ, providing insight into the functions of both RGS14 and 14-3-3 in their roles in modulating synaptic plasticity in the hippocampus.
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Affiliation(s)
- Kyle J Gerber
- From the Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Katherine E Squires
- From the Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322
| | - John R Hepler
- From the Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322
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19
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Ma K, Shi W, Xu M, Liu J, Zhang F. Genome-Wide Identification and Characterization of Long Non-Coding RNA in Wheat Roots in Response to Ca 2+ Channel Blocker. FRONTIERS IN PLANT SCIENCE 2018; 9:244. [PMID: 29559983 PMCID: PMC5845709 DOI: 10.3389/fpls.2018.00244] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 02/12/2018] [Indexed: 05/12/2023]
Abstract
It remains unclear whether plant lncRNAs are responsive to Ca2+-channel blocking. When using the Ca2+-channel blocker, LaCl3, to treat germinated wheat seeds for 24 h, we found that both root length and mitosis were inhibited in the LaCl3-treated groups. The effect of the Ca2+-channel blocker was verified in three ways: a [Ca2+]cyt decrease detected using Fluo-3/AM staining, a decrease in the Ca content measured using inductively coupled plasma mass spectrometry, and an inhibition of Ca2+ influx detected using Non-invasive Micro-test Technology. Genome-wide high throughput RNA-seq and bioinformatical methods were used to identify lncRNAs, and found 177 differentially expressed lncRNAs that might be in responsive to Ca2+-channel blocking. Among these, 108 were up-regulated and 69 were down-regulated. The validity of identified lncRNAs data from RNA-seq was verified using qPCR. GO and KEGG analysis indicated that a number of lncRNAs might be involved in diverse biological processes upon Ca2+-channel blocking. Further GO analysis showed that 23 lncRNAs might play roles as transcription factor (TF); Moreover, eight lncRNAs might participate in cell cycle regulation, and their relative expressions were detected using qPCR. This study also provides diverse data on wheat lncRNAs that can deepen our understanding of the function and regulatory mechanism of Ca2+-channel blocking in plants.
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Affiliation(s)
- Keshi Ma
- College of Life Sciences, Capital Normal University, Beijing, China
- College of Life Science and Agronomy, Zhoukou Normal University, Zhoukou, China
| | - Wenshuo Shi
- College of Life Sciences, Capital Normal University, Beijing, China
| | - Mengyue Xu
- College of Life Sciences, Capital Normal University, Beijing, China
| | - Jiaxi Liu
- College of Life Sciences, Capital Normal University, Beijing, China
- *Correspondence: Jiaxi Liu
| | - Feixiong Zhang
- College of Life Sciences, Capital Normal University, Beijing, China
- Feixiong Zhang
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20
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Hauck PM, Wolf ER, Olivos DJ, McAtarsney CP, Mayo LD. The fate of murine double minute X (MdmX) is dictated by distinct signaling pathways through murine double minute 2 (Mdm2). Oncotarget 2017; 8:104455-104466. [PMID: 29262653 PMCID: PMC5732819 DOI: 10.18632/oncotarget.22320] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 10/05/2017] [Indexed: 01/17/2023] Open
Abstract
Mouse double minute 2 (Mdm2) and MdmX dimerize in response to low levels of genotoxic stress to function in a ubiquitinating complex, which signals for destabilization of p53. Under growth conditions, Mdm2 functions as a neddylating ligase, but the importance and extent of MdmX involvement in this process are largely unknown. Here we show that when Mdm2 functions as a neddylating enzyme, MdmX is stabilized. Furthermore, we demonstrate that under growth conditions, MdmX enhances the neddylation activity of Mdm2 on p53 and is a substrate for neddylation itself. Importantly, MdmX knockdown in MCF-7 breast cancer cells resulted in diminished neddylated p53, suggesting that MdmX is important for Mdm2-mediated neddylation. Supporting this finding, the lack of MdmX in transient assays or in p53/MdmX-/- MEFs results in decreased or altered neddylation of p53 respectively; therefore, MdmX is a critical component of the Mdm2-mediated neddylating complex. c-Src is the upstream activator of this Mdm2-MdmX neddylating pathway and loss of Src signaling leads to the destabilization of MdmX that is dependent on the RING (Really Interesting New Gene) domain of MdmX. Treatment with a small molecule inhibitor of neddylation, MLN4924, results in the activation of Ataxia Telangiectasia Mutated (ATM). ATM phosphorylates Mdm2, converting Mdm2 to a ubiquitinating enzyme which leads to the destabilization of MdmX. These data show how distinct signaling pathways engage neddylating or ubiquitinating activities and impact the Mdm2-MdmX axis.
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Affiliation(s)
- Paula M Hauck
- Department of Pediatrics, Herman B Wells Center for Pediatrics Research, Indianapolis, Indiana, 46202, United States of America
| | - Eric R Wolf
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, 46202, United States of America
| | - David J Olivos
- Department of Pediatrics, Herman B Wells Center for Pediatrics Research, Indianapolis, Indiana, 46202, United States of America
| | - Ciaran P McAtarsney
- Department of Pediatrics, Herman B Wells Center for Pediatrics Research, Indianapolis, Indiana, 46202, United States of America
| | - Lindsey D Mayo
- Department of Pediatrics, Herman B Wells Center for Pediatrics Research, Indianapolis, Indiana, 46202, United States of America.,Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, 46202, United States of America.,Indiana University Simon Cancer Center, Indiana University School of Medicine, Indianapolis, Indiana, 46202, United States of America
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21
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Tan BX, Liew HP, Chua JS, Ghadessy FJ, Tan YS, Lane DP, Coffill CR. Anatomy of Mdm2 and Mdm4 in evolution. J Mol Cell Biol 2017; 9:3-15. [PMID: 28077607 PMCID: PMC6372010 DOI: 10.1093/jmcb/mjx002] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 01/10/2017] [Indexed: 01/09/2023] Open
Abstract
Mouse double minute (Mdm) genes span an evolutionary timeframe from the ancient eukaryotic placozoa Trichoplax adhaerens to Homo sapiens, implying a significant and possibly conserved cellular role throughout history. Maintenance of DNA integrity and response to DNA damage involve many key regulatory pathways, including precise control over the tumour suppressor protein p53. In most vertebrates, degradation of p53 through proteasomal targeting is primarily mediated by heterodimers of Mdm2 and the Mdm2-related protein Mdm4 (also known as MdmX). Both Mdm2 and Mdm4 have p53-binding regions, acidic domains, zinc fingers, and C-terminal RING domains that are conserved throughout evolution. Vertebrates typically have both Mdm2 and Mdm4 genes, while analyses of sequenced genomes of invertebrate species have identified single Mdm genes, suggesting that a duplication event occurred prior to emergence of jawless vertebrates about 550–440 million years ago. The functional relationship between Mdm and p53 in T. adhaerens, an organism that has existed for 1 billion years, implies that these two proteins have evolved together to maintain a conserved and regulated function.
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Affiliation(s)
- Ban Xiong Tan
- p53 Laboratory, Agency for Science, Technology and Research (A*STAR), 8A Biomedical Grove, Immunos #06-06, Singapore138648, Singapore
| | - Hoe Peng Liew
- p53 Laboratory, Agency for Science, Technology and Research (A*STAR), 8A Biomedical Grove, Immunos #06-06, Singapore138648, Singapore
| | - Joy S Chua
- p53 Laboratory, Agency for Science, Technology and Research (A*STAR), 8A Biomedical Grove, Immunos #06-06, Singapore138648, Singapore
| | - Farid J Ghadessy
- p53 Laboratory, Agency for Science, Technology and Research (A*STAR), 8A Biomedical Grove, Immunos #06-06, Singapore138648, Singapore
| | - Yaw Sing Tan
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), 30 Biopolis St, #07-01,Singapore138671, Singapore
| | - David P Lane
- p53 Laboratory, Agency for Science, Technology and Research (A*STAR), 8A Biomedical Grove, Immunos #06-06, Singapore138648, Singapore
| | - Cynthia R Coffill
- p53 Laboratory, Agency for Science, Technology and Research (A*STAR), 8A Biomedical Grove, Immunos #06-06, Singapore138648, Singapore
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22
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Yu Q, Wu W, Tian X, Jia F, Xu L, Dai R, Li X. Comparative proteomics to reveal muscle-specific beef color stability of Holstein cattle during post-mortem storage. Food Chem 2017; 229:769-778. [DOI: 10.1016/j.foodchem.2017.03.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 02/20/2017] [Accepted: 03/01/2017] [Indexed: 12/11/2022]
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23
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Chen Y, Wang YG, Li Y, Sun XX, Dai MS. Otub1 stabilizes MDMX and promotes its proapoptotic function at the mitochondria. Oncotarget 2017; 8:11053-11062. [PMID: 28035068 PMCID: PMC5355245 DOI: 10.18632/oncotarget.14278] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 12/20/2016] [Indexed: 11/25/2022] Open
Abstract
Otub1 regulates p53 stability and activity via non-canonical inhibition of UbcH5, the MDM2 cognate ubiquitin-conjugating enzyme (E2). However, whether Otub1 regulates MDMX stability and activity is not clear. Here we report that Otub1 also suppresses MDM2-mediated MDMX ubiquitination in cells and in vitro, independently of its deubiquitinating enzyme activity. Consequently, overexpression of Otub1 markedly stabilized MDMX and increased its levels, whereas knockdown of Otub1 reduced the levels of MDMX. Interestingly, MDMX induced by Otub1 can localize to mitochondria in addition to the cytosol, enhance p53 phosphorylation at S46 (p53S46P) and promote mitochondria-mediated apoptotic pathway. Knockdown of MDMX reduced Otub1-induced p53S46P, which was shown to be critical for p53's mitochondrial function and apoptotic activity. Furthermore, Otub1 promotes UV-irradiation-induced p53S46P and apoptosis, which can be significantly inhibited by MDMX depletion. Together, these results suggest that Otub1 stabilizes MDMX and promotes p53S46P and mitochondria-mediated apoptosis, providing an alternative mechanism of Otub1's role in apoptosis.
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Affiliation(s)
- Yingxiao Chen
- Department of Molecular and Medical Genetics, School of Medicine, and The OHSU Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | - Yue-Gang Wang
- Department of Molecular and Medical Genetics, School of Medicine, and The OHSU Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | - Yuhuang Li
- Department of Molecular and Medical Genetics, School of Medicine, and The OHSU Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | - Xiao-Xin Sun
- Department of Molecular and Medical Genetics, School of Medicine, and The OHSU Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | - Mu-Shui Dai
- Department of Molecular and Medical Genetics, School of Medicine, and The OHSU Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97239, USA
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24
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Wang H, Zhi H, Ma D, Li T. MiR-217 promoted the proliferation and invasion of glioblastoma by repressing YWHAG. Cytokine 2017; 92:93-102. [DOI: 10.1016/j.cyto.2016.12.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 12/07/2016] [Accepted: 12/21/2016] [Indexed: 12/11/2022]
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25
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Zhou X, Cao B, Lu H. Negative auto-regulators trap p53 in their web. J Mol Cell Biol 2017; 9:62-68. [PMID: 28069666 PMCID: PMC5907828 DOI: 10.1093/jmcb/mjx001] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 11/14/2016] [Accepted: 01/06/2017] [Indexed: 01/07/2023] Open
Abstract
The transcriptional factor p53 activates the expression of a myriad of target genes involving a complicated signalling network, resulting in various cellular outcomes, such as growth arrest, senescence, apoptosis, and metabolic changes, and leading to consequent suppression of tumour growth and progression. Because of the profoundly adverse effect of p53 on growth and proliferation of cancer cells, several feedback mechanisms have been employed by the cells to constrain p53 activity. Two major antagonists MDM2 and MDMX (the long forms) are transcriptionally induced by p53, but in return block p53 activity, forming a negative feedback circuit and rendering chemoresistance of several cancer cells. However, they are not alone, as cancer cells also employ other proteins encoded by p53 target genes to inhibit p53 activity at transcriptional, translational, and posttranslational levels. This essay is thus composed to review a recent progress in understanding the mechanisms for how cancer cells hijack the p53 autoregulation by these proteins for their growth advantage and to discuss the clinical implications of these autoregulatory loops.
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Affiliation(s)
- Xiang Zhou
- Fudan University Shanghai Cancer Center and the Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
| | - Bo Cao
- Department of Biochemistry & Molecular Biology and Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Hua Lu
- Department of Biochemistry & Molecular Biology and Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA
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26
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Zhang Y, Zeng SX, Hao Q, Lu H. Monitoring p53 by MDM2 and MDMX is required for endocrine pancreas development and function in a spatio-temporal manner. Dev Biol 2017; 423:34-45. [PMID: 28118981 DOI: 10.1016/j.ydbio.2017.01.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 01/19/2017] [Accepted: 01/20/2017] [Indexed: 02/06/2023]
Abstract
Although p53 is not essential for normal embryonic development, it plays a pivotal role in many biological and pathological processes, including cell fate determination-dependent and independent events and diseases. The expression and activity of p53 largely depend on its two biological inhibitors, MDM2 and MDMX, which have been shown to form a complex in order to tightly control p53 to an undetectable level during early stages of embryonic development. However, more delicate studies using conditional gene-modification mouse models show that MDM2 and MDMX may function separately or synergistically on p53 regulation during later stages of embryonic development and adulthood in a cell and tissue-specific manner. Here, we report the role of the MDM2/MDMX-p53 pathway in pancreatic islet morphogenesis and functional maintenance, using mouse lines with specific deletion of MDM2 or MDMX in pancreatic endocrine progenitor cells. Interestingly, deletion of MDM2 results in defects of embryonic endocrine pancreas development, followed by neonatal hyperglycemia and lethality, by inducing pancreatic progenitor cell apoptosis and inhibiting cell proliferation. However, unlike MDM2-knockout animals, mice lacking MDMX in endocrine progenitor cells develop normally. But, surprisingly, the survival rate of adult MDMX-knockout mice drastically declines compared to control mice, as blockage of neonatal development of endocrine pancreas by inhibition of cell proliferation and subsequent islet dysfunction and hyperglycemia eventually lead to type 1 diabetes-like disease with advanced diabetic nephropathy. As expected, both MDM2 and MDMX deletion-caused pancreatic defects are completely rescued by loss of p53, verifying the crucial role of the MDM2 and/or MDMX in regulating p53 in a spatio-temporal manner during the development, functional maintenance, and related disease progress of endocrine pancreas. Also, our study suggests a possible mouse model of advanced diabetic nephropathy, which is complementary to other established diabetic models and perhaps useful for the development of anti-diabetes therapies.
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Affiliation(s)
- Yiwei Zhang
- Department of Biochemistry & Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA; Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Shelya X Zeng
- Department of Biochemistry & Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA; Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Qian Hao
- Department of Biochemistry & Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Hua Lu
- Department of Biochemistry & Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA; Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA.
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27
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Xiong S, Pant V, Zhang Y, Aryal NK, You MJ, Kusewitt D, Lozano G. The p53 inhibitor Mdm4 cooperates with multiple genetic lesions in tumourigenesis. J Pathol 2017; 241:501-510. [PMID: 27925213 DOI: 10.1002/path.4854] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 10/19/2016] [Accepted: 11/14/2016] [Indexed: 12/12/2022]
Abstract
The p53 inhibitor Mdm4 is present at high levels in multiple human cancers. Overexpression of Mdm4 in mice drives the spontaneous development of mostly lymphomas and sarcomas. In this study, we explored the ability of Mdm4 to cooperate with lesions in tumour development. The Mdm4 transgene contributed to mammary tumour development in a BALB/cJ background. High levels of Mdm4 enhanced tumour development in a mutant p53R172H heterozygous background, and reduced the need to lose the wild-type p53 allele, as compared with mice heterozygous only for the p53R172H mutation. Additionally, high levels of Mdm4 cooperated with an oncogenic K-ras mutation to drive lung tumourigenesis in vivo. Finally, we examined p53-independent functions of Mdm4 by studying the contribution of Mdm4 to tumour development in the absence of p53. Whereas the overall survival times of p53-null mice with and without the Mdm4 transgene were similar, male mice with both alterations showed significantly shorter survival than p53-null male mice, and showed differences in tumour spectrum, demonstrating a p53-independent function of Mdm4 in tumourigenesis. Furthermore, p53-null mice with the highest level of Mdm4 tended to have multiple tumours. Thus, a detailed analysis of Mdm4 transgenic mice in various genetic backgrounds shows synergy in tumour development in vivo. Mdm4 may thus serve as a therapeutic target in cancers. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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Affiliation(s)
- Shunbin Xiong
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Vinod Pant
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Yun Zhang
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Neeraj K Aryal
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - M James You
- Department of Hematopathology, The University of Texas MD. Anderson Cancer Center, Houston, TX, USA
| | - Donna Kusewitt
- Department of Carcinogenesis, Science Park Research Division, MD Anderson Cancer Center, University of Texas, Smithville, TX, USA
| | - Guillermina Lozano
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
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28
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Abstract
The p53 tumor suppressor is highly regulated at the level of protein degradation and transcriptional activity. The key players of the pathway, p53, MDM2, and MDMX are present at multiple conformational states that are responsive to regulation by post-translational modifications and protein-protein interactions. The structures of major functional domains of these proteins have been determined, but the mechanisms of several intrinsically disordered regions remain unclear despite their critical roles in signaling and regulation. Recent studies suggest that these disordered regions function in part by dynamic intra molecular interactions with the structured domains to regulate p53 DNA binding, MDM2 ubiquitin E3 ligase activity, and MDMX-p53 binding. These findings provide new insight on how p53 is controlled by various stress signals, and suggest potential targets for the search of allosteric regulators of the p53 pathway.
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Affiliation(s)
- Jiandong Chen
- Molecular Oncology Department, H. Lee Moffitt Cancer Center, Tampa, FL, USA
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29
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de Polo A, Vivekanandan V, Little JB, Yuan ZM. MDMX under stress: the MDMX-MDM2 complex as stress signals hub. Transl Cancer Res 2016; 5:725-732. [PMID: 30319942 DOI: 10.21037/tcr.2016.12.18] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The tumor suppressor p53 plays a central role in safeguarding cellular homeostasis. Upon various types of stress signals such as DNA damage or oncogenic stress, p53 is promptly activated to prevent and repair damages that can threaten the genome stability. The two major negative regulators of p53 are MDM2 and MDMX, two homolog proteins that control p53 activity and turnover, hence keeping it in check during normal cell cycling. In the event of cellular stress, they have to be inhibited in order to relieve p53 from their suppression and allow its activation. As the essential upstream modulator of p53, the MDMX-MDM2 complex integrates multiple signaling pathways regulating p53 response to perturbations of cellular homeostasis. Given its predominantly cytoplasmic localization in normal conditions, we hypothesize that MDMX, rather than MDM2, is the first recipient of signaling cues directed towards the MDMX-MDM2 complex and aimed at modulating p53. In this review we give a synthetic overview of the phosphorylation sites of MDMX that are known to affect its degradation, ubiquitination, intracellular localization and interaction with MDM2 and p53, ultimately modulating the stability and activity of p53. The role of MDMX in response to the main types of cellular stress is also briefly discussed, along with the potential of the MDMX-MDM2 complex as therapeutic target to restore p53 activity.
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Affiliation(s)
- Anna de Polo
- John B. Little Center for Radiation Sciences, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Varunika Vivekanandan
- John B. Little Center for Radiation Sciences, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - John B Little
- John B. Little Center for Radiation Sciences, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Zhi-Min Yuan
- John B. Little Center for Radiation Sciences, Harvard T.H. Chan School of Public Health, Boston, MA, USA
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30
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Dzamba M, Ramani AK, Buczkowicz P, Jiang Y, Yu M, Hawkins C, Brudno M. Identification of complex genomic rearrangements in cancers using CouGaR. Genome Res 2016; 27:107-117. [PMID: 27986820 PMCID: PMC5204335 DOI: 10.1101/gr.211201.116] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 11/10/2016] [Indexed: 12/17/2022]
Abstract
The genomic alterations associated with cancers are numerous and varied, involving both isolated and large-scale complex genomic rearrangements (CGRs). Although the underlying mechanisms are not well understood, CGRs have been implicated in tumorigenesis. Here, we introduce CouGaR, a novel method for characterizing the genomic structure of amplified CGRs, leveraging both depth of coverage (DOC) and discordant pair-end mapping techniques. We applied our method to whole-genome sequencing (WGS) samples from The Cancer Genome Atlas and identify amplified CGRs in at least 5.2% (10+ copies) to 17.8% (6+ copies) of the samples. Furthermore, ∼95% of these amplified CGRs contain genes previously implicated in tumorigenesis, indicating the importance and widespread occurrence of CGRs in cancers. Additionally, CouGaR identified the occurrence of 'chromoplexy' in nearly 63% of all prostate cancer samples and 30% of all bladder cancer samples. To further validate the accuracy of our method, we experimentally tested 17 predicted fusions in two pediatric glioma samples and validated 15 of these (88%) with precise resolution of the breakpoints via qPCR experiments and Sanger sequencing, with nearly perfect copy count concordance. Additionally, to further help display and understand the structure of CGRs, we have implemented CouGaR-viz, a generic stand-alone tool for visualization of the copy count of regions, breakpoints, and relevant genes.
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Affiliation(s)
- Misko Dzamba
- Department of Computer Science, University of Toronto, Toronto, Ontario, M5S 3G4, Canada
| | - Arun K Ramani
- Centre for Computational Medicine, The Hospital for Sick Children, Toronto, Ontario, M5G 0A4, Canada
| | - Pawel Buczkowicz
- Division of Pathology, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, M5G 1E8, Canada.,Arthur and Sonia Labatt Brain Tumor Research Centre, The Hospital for Sick Children, Toronto, Ontario, M5G 0A4, Canada.,Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, M5G 1E8, Canada
| | - Yue Jiang
- Centre for Computational Medicine, The Hospital for Sick Children, Toronto, Ontario, M5G 0A4, Canada
| | - Man Yu
- Division of Pathology, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, M5G 1E8, Canada.,Arthur and Sonia Labatt Brain Tumor Research Centre, The Hospital for Sick Children, Toronto, Ontario, M5G 0A4, Canada.,Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, M5G 1E8, Canada
| | - Cynthia Hawkins
- Division of Pathology, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, M5G 1E8, Canada.,Arthur and Sonia Labatt Brain Tumor Research Centre, The Hospital for Sick Children, Toronto, Ontario, M5G 0A4, Canada.,Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, M5G 1E8, Canada
| | - Michael Brudno
- Department of Computer Science, University of Toronto, Toronto, Ontario, M5S 3G4, Canada.,Centre for Computational Medicine, The Hospital for Sick Children, Toronto, Ontario, M5G 0A4, Canada
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31
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Cao B, Wang K, Liao JM, Zhou X, Liao P, Zeng SX, He M, Chen L, He Y, Li W, Lu H. Inactivation of oncogenic cAMP-specific phosphodiesterase 4D by miR-139-5p in response to p53 activation. eLife 2016; 5. [PMID: 27383270 PMCID: PMC4959878 DOI: 10.7554/elife.15978] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 06/29/2016] [Indexed: 12/13/2022] Open
Abstract
Increasing evidence highlights the important roles of microRNAs in mediating p53’s tumor suppression functions. Here, we report miR-139-5p as another new p53 microRNA target. p53 induced the transcription of miR-139-5p, which in turn suppressed the protein levels of phosphodiesterase 4D (PDE4D), an oncogenic protein involved in multiple tumor promoting processes. Knockdown of p53 reversed these effects. Also, overexpression of miR-139-5p decreased PDE4D levels and increased cellular cAMP levels, leading to BIM-mediated cell growth arrest. Furthermore, our analysis of human colorectal tumor specimens revealed significant inverse correlation between the expression of miR-139-5p and that of PDE4D. Finally, overexpression of miR-139-5p suppressed the growth of xenograft tumors, accompanied by decrease in PDE4D and increase in BIM. These results demonstrate that p53 inactivates oncogenic PDE4D by inducing the expression of miR-139-5p. DOI:http://dx.doi.org/10.7554/eLife.15978.001 The human body is kept mostly free from tumors by the actions of so-called tumor suppressor genes. One such gene encodes a protein called p53, which prevents tumors from growing by regulating the activity of many other genes that either inhibit cell growth or cause cells to die. For example, p53 regulates genes that encode short molecules called microRNAs, which in turn suppress the activity of other target genes. Although a number of microRNAs have been reported as p53-regulated genes, there are still more to find. Discovering these genes would in turn help researchers to better understand exactly how p53 acts to suppress the growth of tumors, and to treat cancers caused by mutations in this tumor suppressor gene. Cao, Wang et al. now discover a new microRNA – called miR-139-5p – as one that is activated by p53 in human cells. Colon tumors produce much lower levels of this microRNA than normal tissues, while the cancer cells with a higher level of miR-139-5p grow slower than do the cancer cells with less miR-139-5p. Further experiments showed that this is because miR-139-5p can suppress the production of a protein called PDE4D, which is often highly expressed in human cancers. The suppression of PDE4D by this microRNA results in an increase in the levels of a protein that can cause cancer cells to die. Cao, Wang et al. suggest that miR-139-5p and PDE4D form part of a signaling pathway that plays an important role in suppressing the growth of colon cancer cells. Since microRNAs often have more than one target, future studies could explore if miR-139-5p regulates the production of other cancer-related proteins as well. DOI:http://dx.doi.org/10.7554/eLife.15978.002
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Affiliation(s)
- Bo Cao
- Department of Biochemistry and Molecular Biology, Tulane Cancer Center, Tulane University School of Medicine, New Orleans, United States
| | - Kebing Wang
- Laboratory of General Surgery, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Jun-Ming Liao
- Department of Biochemistry and Molecular Biology, Tulane Cancer Center, Tulane University School of Medicine, New Orleans, United States
| | - Xiang Zhou
- Department of Biochemistry and Molecular Biology, Tulane Cancer Center, Tulane University School of Medicine, New Orleans, United States
| | - Peng Liao
- Department of Biochemistry and Molecular Biology, Tulane Cancer Center, Tulane University School of Medicine, New Orleans, United States
| | - Shelya X Zeng
- Department of Biochemistry and Molecular Biology, Tulane Cancer Center, Tulane University School of Medicine, New Orleans, United States
| | - Meifang He
- Laboratory of General Surgery, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Lianzhou Chen
- Laboratory of General Surgery, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Yulong He
- Department of Gastrointestinal Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Wen Li
- Laboratory of General Surgery, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Hua Lu
- Department of Biochemistry and Molecular Biology, Tulane Cancer Center, Tulane University School of Medicine, New Orleans, United States
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32
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Liao JM, Cao B, Deng J, Zhou X, Strong M, Zeng S, Xiong J, Flemington E, Lu H. TFIIS.h, a new target of p53, regulates transcription efficiency of pro-apoptotic bax gene. Sci Rep 2016; 6:23542. [PMID: 27005522 PMCID: PMC4804275 DOI: 10.1038/srep23542] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 03/03/2016] [Indexed: 11/09/2022] Open
Abstract
Tumor suppressor p53 transcriptionally regulates hundreds of genes involved in various cellular functions. However, the detailed mechanisms underlying the selection of p53 targets in response to different stresses are still elusive. Here, we identify TFIIS.h, a transcription elongation factor, as a new transcriptional target of p53, and also show that it can enhance the efficiency of transcription elongation of apoptosis-associated bax gene, but not cell cycle-associated p21 (CDKN1A) gene. TFIIS.h is revealed as a p53 target through microarray analysis of RNAs extracted from cells treated with or without inauhzin (INZ), a p53 activator, and further confirmed by RT-q-PCR, western blot, luciferase reporter, and ChIP assays. Interestingly, knocking down TFIIS.h impairs, but overexpressing TFIIS.h promotes, induction of bax, but not other p53 targets including p21, by p53 activation. In addition, overexpression of TFIIS.h induces cell death in a bax- dependent fashion. These findings reveal a mechanism by which p53 utilizes TFIIS.h to selectively promote the transcriptional elongation of the bax gene, upsurging cell death in response to severe DNA damage.
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Affiliation(s)
- Jun-Ming Liao
- Department of Biochemistry &Molecular Biology and Cancer Center, Tulane University School of Medicine, 1430, Louisiana, LA 70112, USA
| | - Bo Cao
- Department of Biochemistry &Molecular Biology and Cancer Center, Tulane University School of Medicine, 1430, Louisiana, LA 70112, USA
| | - Jun Deng
- Department of Biochemistry &Molecular Biology and Cancer Center, Tulane University School of Medicine, 1430, Louisiana, LA 70112, USA.,Department of Oncology, The First Affiliated Hospital of Nanchang University, Nanchang 330006, PR China
| | - Xiang Zhou
- Department of Biochemistry &Molecular Biology and Cancer Center, Tulane University School of Medicine, 1430, Louisiana, LA 70112, USA
| | - Michael Strong
- Department of Pathology and Cancer Center, Tulane University School of Medicine, 1430, Louisiana, LA 70112, USA
| | - Shelya Zeng
- Department of Biochemistry &Molecular Biology and Cancer Center, Tulane University School of Medicine, 1430, Louisiana, LA 70112, USA
| | - Jianping Xiong
- Department of Oncology, The First Affiliated Hospital of Nanchang University, Nanchang 330006, PR China
| | - Erik Flemington
- Department of Pathology and Cancer Center, Tulane University School of Medicine, 1430, Louisiana, LA 70112, USA
| | - Hua Lu
- Department of Biochemistry &Molecular Biology and Cancer Center, Tulane University School of Medicine, 1430, Louisiana, LA 70112, USA
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33
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Abstract
p53 has been studied intensively as a major tumour suppressor that detects oncogenic events in cancer cells and eliminates them through senescence (a permanent non-proliferative state) or apoptosis. Consistent with this role, p53 activity is compromised in a high proportion of all cancer types, either through mutation of the TP53 gene (encoding p53) or changes in the status of p53 modulators. p53 has additional roles, which may overlap with its tumour-suppressive capacity, in processes including the DNA damage response, metabolism, aging, stem cell differentiation and fertility. Moreover, many mutant p53 proteins, termed 'gain-of-function' (GOF), acquire new activities that help drive cancer aggression. p53 is regulated mainly through protein turnover and operates within a negative-feedback loop with its transcriptional target, MDM2 (murine double minute 2), an E3 ubiquitin ligase which mediates the ubiquitylation and proteasomal degradation of p53. Induction of p53 is achieved largely through uncoupling the p53-MDM2 interaction, leading to elevated p53 levels. Various stress stimuli acting on p53 (such as hyperproliferation and DNA damage) use different, but overlapping, mechanisms to achieve this. Additionally, p53 activity is regulated through critical context-specific or fine-tuning events, mediated primarily through post-translational mechanisms, particularly multi-site phosphorylation and acetylation. In the present review, I broadly examine these events, highlighting their regulatory contributions, their ability to integrate signals from cellular events towards providing most appropriate response to stress conditions and their importance for tumour suppression. These are fascinating aspects of molecular oncology that hold the key to understanding the molecular pathology of cancer and the routes by which it may be tackled therapeutically.
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34
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Aghazadeh Y, Papadopoulos V. The role of the 14-3-3 protein family in health, disease, and drug development. Drug Discov Today 2015; 21:278-87. [PMID: 26456530 DOI: 10.1016/j.drudis.2015.09.012] [Citation(s) in RCA: 172] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2015] [Revised: 09/21/2015] [Accepted: 09/29/2015] [Indexed: 11/18/2022]
Abstract
14-3-3 proteins regulate intracellular signaling pathways, such as signal transduction, protein trafficking, cell cycle, and apoptosis. In addition to the ubiquitous roles of 14-3-3 isoforms, unique tissue-specific functions are also described for each isoform. Owing to their role in regulating cell cycle, protein trafficking, and steroidogenesis, 14-3-3 proteins are prevalent in human diseases, such as cancer, neurodegeneration, and reproductive disorders, and, therefore, serve as valuable drug targets. In this review, we summarize the role of 14-3-3 proteins in normal and disease states, with a focus on 14-3-3γ and ɛ. We also discuss drug compounds targeting 14-3-3 proteins and their potential therapeutic uses.
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Affiliation(s)
- Yasaman Aghazadeh
- The Research Institute of the McGill University Health Centre, Montreal, QC H4A 3J1, Canada; Department of Medicine, McGill University, Montreal, QC H3G 1A4, Canada
| | - Vassilios Papadopoulos
- The Research Institute of the McGill University Health Centre, Montreal, QC H4A 3J1, Canada; Department of Medicine, McGill University, Montreal, QC H3G 1A4, Canada; Department of Pharmacology and Therapeutics, McGill University, Montreal, QC H3G 1Y6, Canada; Department of Biochemistry, McGill University, Montreal, QC H3G 1Y6, Canada.
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35
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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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36
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Molecular Mechanisms of Relationship Between Blood Plasma Beta-globulins and Protein Markers of Renal and Bladder Cancer. BIONANOSCIENCE 2015. [DOI: 10.1007/s12668-015-0165-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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37
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Chen L, Zhang H, Sun J, Wong YH, Han Z, Au DWT, Bajic VB, Qian PY. Proteomic changes in brain tissues of marine medaka (Oryzias melastigma) after chronic exposure to two antifouling compounds: butenolide and 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2014; 157:47-56. [PMID: 25456219 DOI: 10.1016/j.aquatox.2014.09.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 09/21/2014] [Accepted: 09/23/2014] [Indexed: 06/04/2023]
Abstract
SeaNine 211 with active ingredient of 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT) has been used as a "green" antifouling agent worldwide but has raised serious biosafety concerns in coastal environments. DCOIT has the potential to disrupt the neurotransmission in nervous system, but the underlying mechanism has not been clarified. In the present study, we used TMT six-plex labeling coupled with two-dimensional LC-MS/MS analysis to investigate the protein expression profiles in brain tissues of the marine medaka (Oryzias melastigma) after a 28-day exposure to environmentally-realistic concentration of DCOIT at 2.55 μg/L (0.009 μM) or butenolide, one promising antifouling compound, at 2.31 μg/L (0.012 μM). DCOIT and butenolide induced differential expression of 26 and 18 proteins in male brains and of 27 and 23 proteins in female brains, respectively. Distinct mechanisms of toxicity were initiated by DCOIT and butenolide in males, whereas the protein expression profiles were largely similar in females treated by these two compounds. In males, DCOIT exposure mainly led to disruption of mitogen-activated protein kinase (MAPK) signaling pathway, while butenolide affected proteins related to the cytoskeletal disorganization that is considered as a general response to toxicant stress. Furthermore, a sex-dependent protein expression profile was also noted between male and female fish, as evident by the inverse changes in the expressions of common proteins (5 proteins for butenolide- and 2 proteins for DCOIT-exposed fish). Overall, this study provided insight into the molecular mechanisms underlying the toxicity of DCOIT and butenolide. The extremely low concentrations used in this study highlighted the ecological relevance, arguing for thorough assessments of their ecological risks before the commercialization of any new antifouling compound.
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Affiliation(s)
- Lianguo Chen
- Division of Life Science and Environmental Science Programs, Hong Kong University of Science and Technology, Hong Kong, China
| | - Huoming Zhang
- Biosciences Core Laboratory, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Jin Sun
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Yue-Him Wong
- Division of Life Science and Environmental Science Programs, Hong Kong University of Science and Technology, Hong Kong, China
| | - Zhuang Han
- Division of Life Science and Environmental Science Programs, Hong Kong University of Science and Technology, Hong Kong, China
| | - Doris W T Au
- State Key Laboratory in Marine Pollution, Department of Biology and Chemistry, City University of Hong Kong, Hong Kong, China
| | - Vladimir B Bajic
- Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Pei-Yuan Qian
- Division of Life Science and Environmental Science Programs, Hong Kong University of Science and Technology, Hong Kong, China.
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Yu C, Luo C, Qu B, Khudhair N, Gu X, Zang Y, Wang C, Zhang N, Li Q, Gao X. Molecular network including eIF1AX, RPS7, and 14-3-3γ regulates protein translation and cell proliferation in bovine mammary epithelial cells. Arch Biochem Biophys 2014; 564:142-55. [DOI: 10.1016/j.abb.2014.09.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2014] [Revised: 09/21/2014] [Accepted: 09/23/2014] [Indexed: 02/07/2023]
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Zhou X, Hao Q, Zhang Q, Liao JM, Ke JW, Liao P, Cao B, Lu H. Ribosomal proteins L11 and L5 activate TAp73 by overcoming MDM2 inhibition. Cell Death Differ 2014; 22:755-66. [PMID: 25301064 DOI: 10.1038/cdd.2014.167] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 09/09/2014] [Accepted: 09/10/2014] [Indexed: 01/08/2023] Open
Abstract
Over the past decade, a number of ribosomal proteins (RPs) have been found to have a role in activating the tumor suppressor p53 by directly binding to MDM2 and impeding its activity toward p53. Herein, we report that RPL5 and RPL11 can also enhance the transcriptional activity of a p53 homolog TAp73, but through a distinct mechanism. Interestingly, even though RPL5 and RPL11 were not shown to bind to p53, they were able to directly associate with the transactivation domain of TAp73 independently of MDM2 in response to RS. This association led to perturbation of the MDM2-TAp73 interaction, consequently preventing MDM2 from its association with TAp73 target gene promoters. Furthermore, ectopic expression of RPL5 or RPL11 markedly induced TAp73 transcriptional activity by antagonizing MDM2 suppression. Conversely, ablation of either of the RPs compromised TAp73 transcriptional activity, as evident by the reduction of p21 and Puma expression, in response to 5-fluorouracil (5-FU). Consistently, overexpression of RPL5 or RPL11 enhanced, but knockdown of either of them hampered, TAp73-mediated apoptosis. Intriguingly, simultaneous knockdown of TAp73 and either of the RPs was required for rescuing the 5-FU-triggered S-phase arrest of p53-null tumor cells. These results demonstrate a novel mechanism underlying the inhibition of tumor cell proliferation and growth by these two RPs via TAp73 activation.
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Affiliation(s)
- X Zhou
- Department of Biochemistry & Molecular Biology, Tulane Cancer Center; Tulane University School of Medicine; New Orleans, Louisiana, USA
| | - Q Hao
- Department of Biochemistry & Molecular Biology, Tulane Cancer Center; Tulane University School of Medicine; New Orleans, Louisiana, USA
| | - Q Zhang
- Department of Biochemistry & Molecular Biology, Tulane Cancer Center; Tulane University School of Medicine; New Orleans, Louisiana, USA
| | - J-M Liao
- Department of Biochemistry & Molecular Biology, Tulane Cancer Center; Tulane University School of Medicine; New Orleans, Louisiana, USA
| | - J-W Ke
- 1] Department of Biochemistry & Molecular Biology, Tulane Cancer Center; Tulane University School of Medicine; New Orleans, Louisiana, USA [2] Department of Laboratory Medicine; Jiangxi Children's Hospital, Nanchang, Jiangxi, China
| | - P Liao
- Department of Biochemistry & Molecular Biology, Tulane Cancer Center; Tulane University School of Medicine; New Orleans, Louisiana, USA
| | - B Cao
- Department of Biochemistry & Molecular Biology, Tulane Cancer Center; Tulane University School of Medicine; New Orleans, Louisiana, USA
| | - H Lu
- Department of Biochemistry & Molecular Biology, Tulane Cancer Center; Tulane University School of Medicine; New Orleans, Louisiana, USA
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Zhang Y, Zhang X, Lu H. Aberrant activation of p53 due to loss of MDM2 or MDMX causes early lens dysmorphogenesis. Dev Biol 2014; 396:19-30. [PMID: 25263199 DOI: 10.1016/j.ydbio.2014.09.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 09/10/2014] [Accepted: 09/17/2014] [Indexed: 12/28/2022]
Abstract
Although forming a heterodimer or heterooligomer is essential for MDM2 and MDMX to fully control p53 during early embryogenesis, deletion of either MDM2 or MDMX in specific tissues using the loxp-Cre system reveals phenotypic diversity during organ morphogenesis, which can be completely rescued by loss of p53, suggesting the spatiotemporal independence and specificity of the regulation of p53 by MDM2 and MDMX. In this study, we investigated the role of the MDM2-MDMX-p53 pathway in the developing lens that is a relatively independent region integrating cell proliferation, differentiation and apoptosis. Using the mice expressing Cre recombinase specifically in the lens epithelial cells (LECs) beginning at E9.5, we demonstrated that deletion of either MDM2 or MDMX induces apoptosis of LEC and reduces cell proliferation, resulting in lens developmental defect that finally progresses into aphakia. Specifically, the lens defect caused by MDM2 deletion was evident at E10, occurring earlier than that caused by MDMX deletion. These lens defects were completely rescued by loss of two alleles of p53, but not one allele of p53. These results demonstrate that both MDM2 and MDMX are required for monitoring p53 activity during lens development, and they may function independently or synergistically to control p53 and maintain normal lens morphogenesis.
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Affiliation(s)
- Yiwei Zhang
- Department of Biochemistry & Molecular Biology and Tulane Cancer Center, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA 70112, USA
| | - Xin Zhang
- Departments of Ophthalmology, Pathology & Cell Biology, Columbia University, 635 W. 165th Street, EI902A, New York, NY 10032, USA
| | - Hua Lu
- Department of Biochemistry & Molecular Biology and Tulane Cancer Center, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA 70112, USA.
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Aghazadeh Y, Ye X, Blonder J, Papadopoulos V. Protein modifications regulate the role of 14-3-3γ adaptor protein in cAMP-induced steroidogenesis in MA-10 Leydig cells. J Biol Chem 2014; 289:26542-26553. [PMID: 25086053 DOI: 10.1074/jbc.m114.569079] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The 14-3-3 protein family comprises adaptors and scaffolds that regulate intracellular signaling pathways. The 14-3-3γ isoform is a negative regulator of steroidogenesis that is hormonally induced and transiently functions at the initiation of steroidogenesis by delaying maximal steroidogenesis in MA-10 mouse tumor Leydig cells. Treatment of MA-10 cells with the cAMP analog 8-bromo-cAMP (8-Br-cAMP), which stimulates steroidogenesis, triggers the interaction of 14-3-3γ with the steroidogenic acute regulatory protein (STAR) in the cytosol, limiting STAR activity to basal levels. Over time, this interaction ceases, allowing for a 2-fold induction in STAR activity and maximal increase in the rate of steroid formation. The 14-3-3γ/STAR pattern of interaction was found to be opposite that of the 14-3-3γ homodimerization pattern. Phosphorylation and acetylation of 14-3-3γ showed similar patterns to homodimerization and STAR binding, respectively. 14-3-3γ Ser(58) phosphorylation and 14-3-3γ Lys(49) acetylation were blocked using trans-activator of HIV transcription factor 1 peptides coupled to 14-3-3γ sequences containing Ser(58) or Lys(49). Blocking either one of these modifications further induced 8-Br-cAMP-induced steroidogenesis while reducing lipid storage, suggesting that the stored cholesterol is used for steroid formation. Taken together, these results indicate that Ser(58) phosphorylation and Lys(49) acetylation of 14-3-3γ occur in a coordinated time-dependent manner to regulate 14-3-3γ homodimerization. 14-3-3γ Ser(58) phosphorylation is required for STAR interactions under control conditions, and 14-3-3γ Lys(49) acetylation is important for the cAMP-dependent induction of these interactions.
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Affiliation(s)
- Yasaman Aghazadeh
- Research Institute of the McGill University Health Centre and the Department of Medicine and McGill University, Montreal, Quebec H3G 1A4, Canada
| | - Xiaoying Ye
- Protein Characterization Laboratory, Cancer Research Technology Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, NCI, National Institutes of Health, Frederick, Maryland 21702
| | - Josip Blonder
- Protein Characterization Laboratory, Cancer Research Technology Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, NCI, National Institutes of Health, Frederick, Maryland 21702
| | - Vassilios Papadopoulos
- Research Institute of the McGill University Health Centre and the Department of Medicine and McGill University, Montreal, Quebec H3G 1A4, Canada; Departments of Pharmacology and Therapeutics and McGill University, Montreal, Quebec H3G 1A4, Canada; Departments of Biochemistry, McGill University, Montreal, Quebec H3G 1A4, Canada and.
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Sun XX, Dai MS. Deubiquitinating enzyme regulation of the p53 pathway: A lesson from Otub1. World J Biol Chem 2014; 5:75-84. [PMID: 24920999 PMCID: PMC4050119 DOI: 10.4331/wjbc.v5.i2.75] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Revised: 01/11/2014] [Accepted: 03/14/2014] [Indexed: 02/05/2023] Open
Abstract
Deubiquitination has emerged as an important mechanism of p53 regulation. A number of deubiquitinating enzymes (DUBs) from the ubiquitin-specific protease family have been shown to regulate the p53-MDM2-MDMX networks. We recently reported that Otub1, a DUB from the OTU-domain containing protease family, is a novel p53 regulator. Interestingly, Otub1 abrogates p53 ubiquitination and stabilizes and activates p53 in cells independently of its deubiquitinating enzyme activity. Instead, it does so by inhibiting the MDM2 cognate ubiquitin-conjugating enzyme (E2) UbcH5. Otub1 also regulates other biological signaling through this non-canonical mechanism, suppression of E2, including the inhibition of DNA-damage-induced chromatin ubiquitination. Thus, Otub1 evolves as a unique DUB that mainly suppresses E2 to regulate substrates. Here we review the current progress made towards the understanding of the complex regulation of the p53 tumor suppressor pathway by DUBs, the biological function of Otub1 including its positive regulation of p53, and the mechanistic insights into how Otub1 suppresses E2.
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Inauhzin sensitizes p53-dependent cytotoxicity and tumor suppression of chemotherapeutic agents. Neoplasia 2013; 15:523-34. [PMID: 23633924 DOI: 10.1593/neo.13142] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Revised: 02/15/2013] [Accepted: 02/15/2013] [Indexed: 12/20/2022] Open
Abstract
Toxicity and chemoresistance are two major issues to hamper the success of current standard tumor chemotherapy. Combined therapy of agents with different mechanisms of action is a feasible and effective means to minimize the side effects and avoid the resistance to chemotherapeutic drugs while improving the antitumor effects. As the most essential tumor suppressor, p53 or its pathway has been an attractive target to develop a new type of molecule-targeting anticancer therapy. Recently, we identified a small molecule, Inauhzin (INZ), which can specifically activate p53 by inducing its deacetylation. In this study, we tested if combination with INZ could sensitize tumor cells to the current chemotherapeutic drugs, cisplatin (CIS) and doxorubicin (DOX). We found that compared with any single treatment, combination of lower doses of INZ and CIS or DOX significantly promoted apoptosis and cell growth inhibition in human non-small lung cancer and colon cancer cell lines in a p53-dependent fashion. This cooperative effect between INZ and CIS on tumor suppression was also confirmed in a xenograft tumor model. Therefore, this study suggests that specifically targeting the p53 pathway could enhance the sensitivity of cancer cells to chemotherapeutic agents and markedly reduce the doses of the chemotherapy, possibly decreasing its adverse side effects.
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AMP-activated protein kinase induces p53 by phosphorylating MDMX and inhibiting its activity. Mol Cell Biol 2013; 34:148-57. [PMID: 24190973 DOI: 10.1128/mcb.00670-13] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
AMP-activated protein kinase (AMPK) has been shown to activate p53 in response to metabolic stress. However, the underlying mechanisms remain unclear. Here we show that metabolic stresses induce AMPK-mediated phosphorylation of human MDMX on Ser342 in vitro and in cells, leading to enhanced association between MDMX and 14-3-3. This markedly inhibits p53 ubiquitylation and significantly stabilizes and activates p53. By striking contrast, no phosphorylation of MDM2 by AMPK was noted. AMPK-mediated MDMX phosphorylation, MDMX-14-3-3 binding, and p53 activation were drastically reduced in mouse embryo fibroblasts harboring endogenous MDMX with S341A (mouse homologue of human serine 342), S367A, and S402A (mouse homologue of human serine 403) mutations. Moreover, deficiency of AMPK prevented MDMX-14-3-3 interaction and p53 activation. The activation of p53 through AMPK-mediated MDMX phosphorylation and inactivation was further confirmed by using cell and animal model systems with two AMPK activators, metformin and salicylate (the active form of aspirin). Together, the results unveil a mechanism by which metabolic stresses activate AMPK, which, in turn, phosphorylates and inactivates MDMX, resulting in p53 stabilization and activation.
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45
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Liao JM, Zhou X, Gatignol A, Lu H. Ribosomal proteins L5 and L11 co-operatively inactivate c-Myc via RNA-induced silencing complex. Oncogene 2013; 33:4916-23. [PMID: 24141778 PMCID: PMC4026346 DOI: 10.1038/onc.2013.430] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 08/27/2013] [Accepted: 09/13/2013] [Indexed: 01/22/2023]
Abstract
Oncogene MYC is highly expressed in many human cancers and functions as a global regulator of ribosome biogenesis. Previously, we reported that ribosomal protein (RP) L11 binds to c-Myc and inhibits its transcriptional activity in response to ribosomal stress. Here, we show that RPL5, co-operatively with RPL11, guides the RNA-induced silencing complex (RISC) to c-Myc mRNA and mediates the degradation of the mRNA, consequently leading to inhibition of c-Myc activity. Knocking down of RPL5 induced c-Myc expression at both mRNA and protein levels, whereas overexpression of RPL5 suppressed c-Myc expression and activity. Immunoprecipitation revealed that RPL5 binds to 3'UTR of c-Myc mRNA and two subunits of RISC, TRBP (HIV-1 TAR RNA-binding protein) and Ago2, mediating the targeting of c-Myc mRNA by miRNAs. Interestingly, RPL5 and RPL11 co-resided on c-Myc mRNA and suppressed c-Myc expression co-operatively. These findings uncover a mechanism by which these two RPs can co-operatively suppress c-Myc expression, allowing a tightly controlled ribosome biogenesis in cells.
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Affiliation(s)
- J-M Liao
- Department of Biochemistry and Molecular Biology and Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA, USA
| | - X Zhou
- Department of Biochemistry and Molecular Biology and Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA, USA
| | - A Gatignol
- Lady Davis Institute for Medical Research, McGill University AIDS Centre, Montréal, Québec, Canada
| | - H Lu
- Department of Biochemistry and Molecular Biology and Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA, USA
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Zhu Y, Regunath K, Jacq X, Prives C. Cisplatin causes cell death via TAB1 regulation of p53/MDM2/MDMX circuitry. Genes Dev 2013; 27:1739-51. [PMID: 23934659 PMCID: PMC3759692 DOI: 10.1101/gad.212258.112] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The interdependence of p53 and MDM2 is critical for proper cell survival and cell death. Zhu et al. find that TAB1, an activator of TAK1 and p38α, inhibits the E3 ligase activity of MDM2 toward p53 and its homolog, MDMX. Cisplatin-induced cell death is mitigated by TAB1 knockdown. TAB1 stabilizes MDMX and activates p38α to phosphorylate p53, allowing p53 target induction. TAB1 levels are relatively low in cisplatin-resistant clones of ovarian cells and in ovarian tumors, implicating TAB1 as a tumor suppressor. The interdependence of p53 and MDM2 is critical for proper cell survival and cell death and, when altered, can lead to tumorigenesis. Mitogen-activated protein kinase (MAPK) signaling pathways function in a wide variety of cellular processes, including cell growth, migration, differentiation, and death. Here we discovered that transforming growth factor β-activated kinase 1 (TAK1)-binding protein 1 (TAB1), an activator of TAK1 and of p38α, associates with and inhibits the E3 ligase activity of MDM2 toward p53 and its homolog, MDMX. Depletion of TAB1 inhibits MDM2 siRNA-mediated p53 accumulation and p21 induction, partially rescuing cell cycle arrest induced by MDM2 ablation. Interestingly, of several agents commonly used as DNA-damaging therapeutics, only cell death caused by cisplatin is mitigated by knockdown of TAB1. Two mechanisms are required for TAB1 to regulate apoptosis in cisplatin-treated cells. First, p38α is activated by TAB1 to phosphorylate p53 N-terminal sites, leading to selective induction of p53 targets such as NOXA. Second, MDMX is stabilized in a TAB1-dependent manner and is required for cell death after cisplatin treatment. Interestingly TAB1 levels are relatively low in cisplatin-resistant clones of ovarian cells and in ovarian patient's tumors compared with normal ovarian tissue. Together, our results indicate that TAB1 is a potential tumor suppressor that serves as a functional link between p53–MDM2 circuitry and a key MAPK signaling pathway.
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Affiliation(s)
- Yan Zhu
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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Noutsios GT, Silveyra P, Bhatti F, Floros J. Exon B of human surfactant protein A2 mRNA, alone or within its surrounding sequences, interacts with 14-3-3; role of cis-elements and secondary structure. Am J Physiol Lung Cell Mol Physiol 2013; 304:L722-35. [PMID: 23525782 PMCID: PMC3680765 DOI: 10.1152/ajplung.00324.2012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Accepted: 03/03/2013] [Indexed: 01/22/2023] Open
Abstract
Human surfactant protein A, an innate immunity molecule, is encoded by two genes: SFTPA1 (SP-A1) and SFTPA2 (SP-A2). The 5' untranslated (5'UTR) splice variant of SP-A2 (ABD), but not of SP-A1 (AD), contains exon B (eB), which is an enhancer for transcription and translation. We investigated whether eB contains cis-regulatory elements that bind trans-acting factors in a sequence-specific manner as well as the role of the eB mRNA secondary structure. Binding of cytoplasmic NCI-H441 proteins to wild-type eB, eB mutant, AD, and ABD 5'UTR mRNAs were studied by RNA electromobility shift assays (REMSAs). The bound proteins were identified by mass spectroscopy and specific antibodies (Abs). We found that 1) proteins bind eB mRNA in a sequence-specific manner, with two cis-elements identified within eB to be important; 2) eB secondary structure is necessary for binding; 3) mass spectroscopy and specific Abs in REMSAs identified 14-3-3 proteins to bind (directly or indirectly) eB and the natural SP-A2 (ABD) splice variant but not the SP-A1 (AD) splice variant; 4) other ribosomal and cytoskeletal proteins, and translation factors, are also present in the eB mRNA-protein complex; 5) knockdown of 14-3-3 β/α isoform resulted in a downregulation of SP-A2 expression. In conclusion, proteins including the 14-3-3 family bind two cis-elements within eB of hSP-A2 mRNA in a sequence- and secondary structure-specific manner. Differential regulation of SP-A1 and SP-A2 is mediated by the 14-3-3 protein family as well as by a number of other proteins that bind UTRs with or without eB mRNA.
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Affiliation(s)
- Georgios T Noutsios
- Center for Host Defense, Inflammation, and Lung Disease (CHILD) Research Department of Pediatrics, College of Medicine, The Pennsylvania State University, Hershey, PA 17033, USA
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Zhang Y, Hunter T. Roles of Chk1 in cell biology and cancer therapy. Int J Cancer 2013; 134:1013-23. [PMID: 23613359 DOI: 10.1002/ijc.28226] [Citation(s) in RCA: 300] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Accepted: 04/11/2013] [Indexed: 01/05/2023]
Abstract
The evolutionally conserved DNA damage response (DDR) and cell cycle checkpoints preserve genome integrity. Central to these genome surveillance pathways is a protein kinase, Chk1. DNA damage induces activation of Chk1, which then transduces the checkpoint signal and facilitates cell cycle arrest and DNA damage repair. Significant progress has been made recently toward our understanding of Chk1 regulation and its implications in cancer etiology and therapy. Specifically, a model that involves both spatiotemporal and conformational changes of proteins has been proposed for Chk1 activation. Further, emerging evidence suggests that Chk1 does not appear to be a tumor suppressor; instead, it promotes tumor growth and may contribute to anticancer therapy resistance. Recent data from our laboratory suggest that activating, but not inhibiting, Chk1 in the absence of chemotherapy might represent an innovative approach to suppress tumor growth. These findings suggest unique regulation of Chk1 in cell biology and cancer etiology, pointing to novel strategies for targeting Chk1 in cancer therapy.
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Affiliation(s)
- Youwei Zhang
- Department of Pharmacology, Case Comprehensive Cancer Center, School of Medicine, Case Western Reserve University, Cleveland, OH
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Liao JM, Zhang Y, Liao W, Zeng SX, Su X, Flores ER, Lu H. IκB kinase β (IKKβ) inhibits p63 isoform γ (TAp63γ) transcriptional activity. J Biol Chem 2013; 288:18184-93. [PMID: 23589370 DOI: 10.1074/jbc.m113.466540] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Previously, we reported that IκB kinase-β(IKKβ) phosphorylates and stabilizes TAp63γ. However, the effect of this phosphorylation on TAp63γ transcriptional activity remains unclear. In this study, we showed that overexpression of IKKβ, but not its kinase dead mutant and IKKα, can surprisingly inhibit TAp63γ transcriptional activity as measured by luciferase assays and real-time PCR analyses of p63 target genes. This inhibition was impaired by ACHP, an IKKβ inhibitor, and enhanced by TNFα that activates IKKβ. Consistently, IKKβ inhibited the binding between TAp63γ and p300, a co-activator of TAp63γ, and consequently counteracted the positive effect of p300 on TAp63γ transcriptional activity. Through phosphorylation site prediction and mass spectrometry, we identified that Ser-4 and Ser-12 of p63 are IKKβ-targeting residues. As expected, IKKβ fails to suppress the transcriptional activity of the S4A/S12A double mutant p63. These results indicate that IKKβ can suppress TAp63γ activity by interfering with the interaction between TAp63γ and p300.
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Affiliation(s)
- Jun-Ming Liao
- Department of Biochemistry and Molecular Biology and Tulane Cancer Center, Tulane University School of Medicine, New Orleans, Louisiana 70112, USA
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Takeda K, Takata T, Kawai Y, Ishigaki Y, Kajinami K. Chk1-mediated phosphorylation of receptor-associated late transducer at serine 250 increases its stability by stimulating its interaction with 14-3-3. Genes Cells 2013; 18:369-86. [PMID: 23432726 DOI: 10.1111/gtc.12043] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Accepted: 01/23/2013] [Indexed: 01/13/2023]
Abstract
Receptor-associated late transducer (RALT) acts as a negative feedback inhibitor of ErbB receptor signaling via physical interaction with ErbB. Although RALT contains a 14-3-3 binding motif (247-RSHSGP-252), little is known about the molecular basis and significance of binding to 14-3-3. Here, we report that 14-3-3 interacts with RALT in H9c2 and COS-7 cells in a Ser-250 phosphorylation-dependent manner. An in vitro kinase assay showed that RALT is a substrate for checkpoint kinase 1 (Chk1). Interaction between ectopically expressed RALT and endogenous 14-3-3 was partially suppressed by pretreatment with the Chk1 inhibitor, UCN-01. In addition, expression of constitutively active Chk1 (Chk11-365 ) resulted in increased phosphorylation of the RALT 14-3-3 binding motif and enhanced the interaction between RALT and 14-3-3θ. Furthermore, fluorescence microscopy revealed that rapid trafficking of RALT to endosome-like vesicle structures was decelerated by coexpression of Chk11-365 , whereas this coexpression had no significant impact on trafficking of the RALT S250A mutant. Finally, a cycloheximide chase assay indicated that coexpression of Chk11-365 decelerated the degradation of ectopically expressed RALT, but not that of the S250A mutant. Collectively, these results suggest that Chk1 plays a role in regulating RALT protein stability by facilitating the interaction between 14-3-3 and RALT.
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Affiliation(s)
- Kenji Takeda
- Department of Cardiology, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Ishikawa, 920-0293, Japan
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