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Li C, Zhao X, He Y, Li Z, Qian J, Zhang L, Ye Q, Qiu F, Lian P, Qian M, Zhang H. The functional role of inherited CDKN2A variants in childhood acute lymphoblastic leukemia. Pharmacogenet Genomics 2022; 32:43-50. [PMID: 34369425 PMCID: PMC8694244 DOI: 10.1097/fpc.0000000000000451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 07/13/2021] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Genetic alterations in CDKN2A tumor suppressor gene on chromosome 9p21 confer a predisposition to childhood acute lymphoblastic leukemia (ALL). Genome-wide association studies have identified missense variants in CDKN2A associated with the development of ALL. This study systematically evaluated the effects of CDKN2A coding variants on ALL risk. METHODS We genotyped the CDKN2A coding region in 308 childhood ALL cases enrolled in CCCG-ALL-2015 clinical trials by Sanger Sequencing. Cell growth assay, cell cycle assay, MTT-based cell toxicity assay, and western blot were performed to assess the CDKN2A coding variants on ALL predisposition. RESULTS We identified 10 novel exonic germline variants, including 6 missense mutations (p.A21V, p.G45A and p.V115L of p16INK4A; p.T31R, p.R90G, and p.R129L of p14ARF) and 1 nonsense mutation and 1 heterozygous termination codon mutation in exon 2 (p16INK4A p.S129X). Functional studies indicate that five novel variants resulted in reduced tumor suppressor activity of p16INK4A, and increased the susceptibility to the leukemic transformation of hematopoietic progenitor cells. Compared to other variants, p.H142R contributes higher sensitivity to CDK4/6 inhibitors. CONCLUSION These findings provide direct insight into the influence of inherited genetic variants at the CDKN2A coding region on the development of ALL and the precise clinical application of CDK4/6 inhibitors.
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Affiliation(s)
- Chunjie Li
- Department of Hematology/Oncology
- Institute of Pediatrics, Affiliated Guangzhou Women and Children’s Medical Center, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou
| | - Xinying Zhao
- Department of Hematology/Oncology
- Institute of Pediatrics, Affiliated Guangzhou Women and Children’s Medical Center, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou
| | | | - Ziping Li
- Department of Hematology/Oncology
- Institute of Pediatrics, Affiliated Guangzhou Women and Children’s Medical Center, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou
| | - Jiabi Qian
- Department of Hematology/Oncology
- Institute of Pediatrics, Affiliated Guangzhou Women and Children’s Medical Center, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou
| | - Li Zhang
- Department of Hematology/Oncology
| | - Qian Ye
- Department of Hematology/Oncology
| | - Fei Qiu
- Bioinspired Engineering and Biomechanics Center, Xi’an Jiaotong University, Xi’an, China
| | - Peng Lian
- Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Maoxiang Qian
- Institute of Pediatrics and Department of Hematology and Oncology, Children’s Hospital of Fudan University, National Children’s Medical Center, the Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Fudan University, Shanghai, China
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Kung CP, Weber JD. It’s Getting Complicated—A Fresh Look at p53-MDM2-ARF Triangle in Tumorigenesis and Cancer Therapy. Front Cell Dev Biol 2022; 10:818744. [PMID: 35155432 PMCID: PMC8833255 DOI: 10.3389/fcell.2022.818744] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 01/07/2022] [Indexed: 01/31/2023] Open
Abstract
Anti-tumorigenic mechanisms mediated by the tumor suppressor p53, upon oncogenic stresses, are our bodies’ greatest weapons to battle against cancer onset and development. Consequently, factors that possess significant p53-regulating activities have been subjects of serious interest from the cancer research community. Among them, MDM2 and ARF are considered the most influential p53 regulators due to their abilities to inhibit and activate p53 functions, respectively. MDM2 inhibits p53 by promoting ubiquitination and proteasome-mediated degradation of p53, while ARF activates p53 by physically interacting with MDM2 to block its access to p53. This conventional understanding of p53-MDM2-ARF functional triangle have guided the direction of p53 research, as well as the development of p53-based therapeutic strategies for the last 30 years. Our increasing knowledge of this triangle during this time, especially through identification of p53-independent functions of MDM2 and ARF, have uncovered many under-appreciated molecular mechanisms connecting these three proteins. Through recognizing both antagonizing and synergizing relationships among them, our consideration for harnessing these relationships to develop effective cancer therapies needs an update accordingly. In this review, we will re-visit the conventional wisdom regarding p53-MDM2-ARF tumor-regulating mechanisms, highlight impactful studies contributing to the modern look of their relationships, and summarize ongoing efforts to target this pathway for effective cancer treatments. A refreshed appreciation of p53-MDM2-ARF network can bring innovative approaches to develop new generations of genetically-informed and clinically-effective cancer therapies.
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Affiliation(s)
- Che-Pei Kung
- ICCE Institute, St. Louis, MO, United States
- Division of Molecular Oncology, Department of Medicine, St. Louis, MO, United States
- *Correspondence: Che-Pei Kung, ; Jason D. Weber,
| | - Jason D. Weber
- ICCE Institute, St. Louis, MO, United States
- Division of Molecular Oncology, Department of Medicine, St. Louis, MO, United States
- Alvin J. Siteman Cancer Center, Washington University School of Medicine, St. Louis, MO, United States
- *Correspondence: Che-Pei Kung, ; Jason D. Weber,
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Dawes JC, Uren AG. Forward and Reverse Genetics of B Cell Malignancies: From Insertional Mutagenesis to CRISPR-Cas. Front Immunol 2021; 12:670280. [PMID: 34484175 PMCID: PMC8414522 DOI: 10.3389/fimmu.2021.670280] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 07/09/2021] [Indexed: 12/21/2022] Open
Abstract
Cancer genome sequencing has identified dozens of mutations with a putative role in lymphomagenesis and leukemogenesis. Validation of driver mutations responsible for B cell neoplasms is complicated by the volume of mutations worthy of investigation and by the complex ways that multiple mutations arising from different stages of B cell development can cooperate. Forward and reverse genetic strategies in mice can provide complementary validation of human driver genes and in some cases comparative genomics of these models with human tumors has directed the identification of new drivers in human malignancies. We review a collection of forward genetic screens performed using insertional mutagenesis, chemical mutagenesis and exome sequencing and discuss how the high coverage of subclonal mutations in insertional mutagenesis screens can identify cooperating mutations at rates not possible using human tumor genomes. We also compare a set of independently conducted screens from Pax5 mutant mice that converge upon a common set of mutations observed in human acute lymphoblastic leukemia (ALL). We also discuss reverse genetic models and screens that use CRISPR-Cas, ORFs and shRNAs to provide high throughput in vivo proof of oncogenic function, with an emphasis on models using adoptive transfer of ex vivo cultured cells. Finally, we summarize mouse models that offer temporal regulation of candidate genes in an in vivo setting to demonstrate the potential of their encoded proteins as therapeutic targets.
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Affiliation(s)
- Joanna C Dawes
- Medical Research Council, London Institute of Medical Sciences, London, United Kingdom.,Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Anthony G Uren
- Medical Research Council, London Institute of Medical Sciences, London, United Kingdom.,Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London, United Kingdom
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Wu TT, Liu T, Li X, Chen YJ, Chen TJ, Zhu XY, Chen JL, Li Q, Liu Y, Feng Y, Wu YC. TET2-mediated Cdkn2A DNA hydroxymethylation in midbrain dopaminergic neuron injury of Parkinson's disease. Hum Mol Genet 2021; 29:1239-1252. [PMID: 32037456 DOI: 10.1093/hmg/ddaa022] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 01/03/2020] [Accepted: 02/03/2020] [Indexed: 12/31/2022] Open
Abstract
It has been reported that abnormal epigenetic modification is associated with the occurrence of Parkinson's disease (PD). Here, we found that a ten-eleven translocation 2 (TET2), a staff of the DNA hydroxylases family, was increased in dopaminergic neurons in vitro and in vivo. Genome-wide mapping of DNA 5-hydroxymethylcytosine (5-hmC)-sequencing has revealed an aberrant epigenome 5-hmC landscape in 1-methyl-4-phenylpyridinium iodide (MPP+)-induced SH-SY5Y cells. The TET family of DNA hydroxylases could reverse DNA methylation by oxidization of 5-methylcytosine (5-mC) to 5-hmC. However, the relationship between modification of DNA hydroxymethylation and the pathogenesis of PD is not clear. According to the results of 5-hmC-sequencing studies, 5-hmC was associated with gene-rich regions in the genomes related to cell cycle, especially gene-cyclin-dependent kinase inhibitor 2A (Cdkn2A). Downregulation of TET2 expression could significantly rescue MPP+-stimulated SH-SY5Y cell damage and cell cycle arrest. Meanwhile, knockdown of Tet2 expression in the substantia nigra pars compacta of MPTP-induced PD mice resulted in attenuated MPTP-induced motor deficits and dopaminergic neuronal injury via p16 suppression. In this study, we demonstrated a critical function of TET2 in PD development via the CDKN2A activity-dependent epigenetic pathway, suggesting a potential new strategy for epigenetic therapy.
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Affiliation(s)
- Ting-Ting Wu
- Department of Neurology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, P.R. China
| | - Te Liu
- Shanghai Geriatric Institute of Chinese Medicine, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200031, P.R. China
| | - Xuan Li
- Department of Neurology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, P.R. China
| | - Ya-Jing Chen
- Department of Neurology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, P.R. China
| | - Tian-Jiao Chen
- Department of Neurology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, P.R. China
| | - Xiao-Ying Zhu
- Department of Neurology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, P.R. China
| | - Jiu-Lin Chen
- Shanghai Geriatric Institute of Chinese Medicine, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200031, P.R. China
| | - Qing Li
- The State Key Laboratory of Medical Neurobiology, The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai 200032, P.R. China
| | - Ye Liu
- Department of Neurology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, P.R. China
| | - Ya Feng
- Department of Neurology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, P.R. China
| | - Yun-Cheng Wu
- Department of Neurology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, P.R. China
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Lahalle A, Lacroix M, De Blasio C, Cissé MY, Linares LK, Le Cam L. The p53 Pathway and Metabolism: The Tree That Hides the Forest. Cancers (Basel) 2021; 13:cancers13010133. [PMID: 33406607 PMCID: PMC7796211 DOI: 10.3390/cancers13010133] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 12/28/2020] [Accepted: 12/28/2020] [Indexed: 12/18/2022] Open
Abstract
Simple Summary The p53 pathway is a major tumor suppressor pathway that prevents the propagation of abnormal cells by regulating DNA repair, cell cycle progression, cell death, or senescence. The multiple cellular processes regulated by p53 were more recently extended to the control of metabolism, and many studies support the notion that perturbations of p53-associated metabolic activities are linked to cancer development. Converging lines of evidence support the notion that, in addition to p53, other key components of this molecular cascade are also important regulators of metabolism. Here, we illustrate the underestimated complexity of the metabolic network controlled by the p53 pathway and show how its perturbation contributes to human diseases including cancer, aging, and metabolic diseases. Abstract The p53 pathway is functionally inactivated in most, if not all, human cancers. The p53 protein is a central effector of numerous stress-related molecular cascades. p53 controls a safeguard mechanism that prevents accumulation of abnormal cells and their transformation by regulating DNA repair, cell cycle progression, cell death, or senescence. The multiple cellular processes regulated by p53 were more recently extended to the control of metabolism and many studies support the notion that perturbations of p53-associated metabolic activities are linked to cancer development, as well as to other pathophysiological conditions including aging, type II diabetes, and liver disease. Although much less documented than p53 metabolic activities, converging lines of evidence indicate that other key components of this tumor suppressor pathway are also involved in cellular metabolism through p53-dependent as well as p53-independent mechanisms. Thus, at least from a metabolic standpoint, the p53 pathway must be considered as a non-linear pathway, but the complex metabolic network controlled by these p53 regulators and the mechanisms by which their activities are coordinated with p53 metabolic functions remain poorly understood. In this review, we highlight some of the metabolic pathways controlled by several central components of the p53 pathway and their role in tissue homeostasis, metabolic diseases, and cancer.
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Affiliation(s)
- Airelle Lahalle
- Université de Montpellier, F-34090 Montpellier, France; (A.L.); (M.L.); (C.D.B.); (L.K.L.)
- IRCM, Institut de Recherche en Cancérologie de Montpellier, F-34298 Montpellier, France
- ICM, Institut Régional du Cancer de Montpellier, F-34298 Montpellier, France
- INSERM, Institut National de la Santé et de la Recherche Médicale, U1194, F-24298 Montpellier, France
- Equipe Labellisée Ligue Contre le Cancer, F-75013 Paris, France
| | - Matthieu Lacroix
- Université de Montpellier, F-34090 Montpellier, France; (A.L.); (M.L.); (C.D.B.); (L.K.L.)
- IRCM, Institut de Recherche en Cancérologie de Montpellier, F-34298 Montpellier, France
- ICM, Institut Régional du Cancer de Montpellier, F-34298 Montpellier, France
- INSERM, Institut National de la Santé et de la Recherche Médicale, U1194, F-24298 Montpellier, France
- Equipe Labellisée Ligue Contre le Cancer, F-75013 Paris, France
| | - Carlo De Blasio
- Université de Montpellier, F-34090 Montpellier, France; (A.L.); (M.L.); (C.D.B.); (L.K.L.)
- IRCM, Institut de Recherche en Cancérologie de Montpellier, F-34298 Montpellier, France
- ICM, Institut Régional du Cancer de Montpellier, F-34298 Montpellier, France
- INSERM, Institut National de la Santé et de la Recherche Médicale, U1194, F-24298 Montpellier, France
- Equipe Labellisée Ligue Contre le Cancer, F-75013 Paris, France
| | - Madi Y. Cissé
- Department of Molecular Metabolism, Harvard, T.H Chan School of Public Health, Boston, MA 02115, USA;
| | - Laetitia K. Linares
- Université de Montpellier, F-34090 Montpellier, France; (A.L.); (M.L.); (C.D.B.); (L.K.L.)
- IRCM, Institut de Recherche en Cancérologie de Montpellier, F-34298 Montpellier, France
- ICM, Institut Régional du Cancer de Montpellier, F-34298 Montpellier, France
- INSERM, Institut National de la Santé et de la Recherche Médicale, U1194, F-24298 Montpellier, France
| | - Laurent Le Cam
- Université de Montpellier, F-34090 Montpellier, France; (A.L.); (M.L.); (C.D.B.); (L.K.L.)
- IRCM, Institut de Recherche en Cancérologie de Montpellier, F-34298 Montpellier, France
- ICM, Institut Régional du Cancer de Montpellier, F-34298 Montpellier, France
- INSERM, Institut National de la Santé et de la Recherche Médicale, U1194, F-24298 Montpellier, France
- Equipe Labellisée Ligue Contre le Cancer, F-75013 Paris, France
- Correspondence:
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Koss B, Shields BD, Taylor EM, Storey AJ, Byrum SD, Gies AJ, Washam CL, Choudhury SR, Hyun Ahn J, Uryu H, Williams JB, Krager KJ, Chiang TC, Mackintosh SG, Edmondson RD, Aykin-Burns N, Gajewski TF, Wang GG, Tackett AJ. Epigenetic Control of Cdkn2a.Arf Protects Tumor-Infiltrating Lymphocytes from Metabolic Exhaustion. Cancer Res 2020; 80:4707-4719. [PMID: 33004350 PMCID: PMC7642172 DOI: 10.1158/0008-5472.can-20-0524] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 06/04/2020] [Accepted: 08/28/2020] [Indexed: 01/06/2023]
Abstract
T-cell exhaustion in cancer is linked to poor clinical outcomes, where evidence suggests T-cell metabolic changes precede functional exhaustion. Direct competition between tumor-infiltrating lymphocytes (TIL) and cancer cells for metabolic resources often renders T cells dysfunctional. Environmental stress produces epigenome remodeling events within TIL resulting from loss of the histone methyltransferase EZH2. Here, we report an epigenetic mechanism contributing to the development of metabolic exhaustion in TIL. A multiomics approach revealed a Cdkn2a.Arf-mediated, p53-independent mechanism by which EZH2 inhibition leads to mitochondrial dysfunction and the resultant exhaustion. Reprogramming T cells to express a gain-of-function EZH2 mutant resulted in an enhanced ability of T cells to inhibit tumor growth in vitro and in vivo. Our data suggest that manipulation of T-cell EZH2 within the context of cellular therapies may yield lymphocytes that are able to withstand harsh tumor metabolic environments and collateral pharmacologic insults. SIGNIFICANCE: These findings demonstrate that manipulation of T-cell EZH2 in cellular therapies may yield cellular products able to withstand solid tumor metabolic-deficient environments. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/21/4707/F1.large.jpg.
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Affiliation(s)
- Brian Koss
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Bradley D Shields
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Erin M Taylor
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Aaron J Storey
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Stephanie D Byrum
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas
- Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas
- Arkansas Children's Research Institute, Little Rock, Arkansas
| | - Allen J Gies
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas
- Arkansas Children's Research Institute, Little Rock, Arkansas
| | - Charity L Washam
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas
- Arkansas Children's Research Institute, Little Rock, Arkansas
| | - Samrat Roy Choudhury
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Jeong Hyun Ahn
- Lineberger Comprehensive Cancer Center, Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina
| | - Hidetaka Uryu
- Lineberger Comprehensive Cancer Center, Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina
| | - Jason B Williams
- Department of Pathology, The University of Chicago, Chicago, Illinois
| | - Kimberly J Krager
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Tung-Chin Chiang
- Department of Environmental and Occupational Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Samuel G Mackintosh
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Rick D Edmondson
- Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Nukhet Aykin-Burns
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Thomas F Gajewski
- Department of Pathology, The University of Chicago, Chicago, Illinois
| | - Gang Greg Wang
- Lineberger Comprehensive Cancer Center, Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina
| | - Alan J Tackett
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas.
- Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas
- Arkansas Children's Research Institute, Little Rock, Arkansas
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Post-Translational Regulation of ARF: Perspective in Cancer. Biomolecules 2020; 10:biom10081143. [PMID: 32759846 PMCID: PMC7465197 DOI: 10.3390/biom10081143] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 07/25/2020] [Accepted: 07/29/2020] [Indexed: 02/07/2023] Open
Abstract
Tumorigenesis can be induced by various stresses that cause aberrant DNA mutations and unhindered cell proliferation. Under such conditions, normal cells autonomously induce defense mechanisms, thereby stimulating tumor suppressor activation. ARF, encoded by the CDKN2a locus, is one of the most frequently mutated or deleted tumor suppressors in human cancer. The safeguard roles of ARF in tumorigenesis are mainly mediated via the MDM2-p53 axis, which plays a prominent role in tumor suppression. Under normal conditions, low p53 expression is stringently regulated by its target gene, MDM2 E3 ligase, which induces p53 degradation in a ubiquitin-proteasome-dependent manner. Oncogenic signals induced by MYC, RAS, and E2Fs trap MDM2 in the inhibited state by inducing ARF expression as a safeguard measure, thereby activating the tumor-suppressive function of p53. In addition to the MDM2-p53 axis, ARF can also interact with diverse proteins and regulate various cellular functions, such as cellular senescence, apoptosis, and anoikis, in a p53-independent manner. As the evidence indicating ARF as a key tumor suppressor has been accumulated, there is growing evidence that ARF is sophisticatedly fine-tuned by the diverse factors through transcriptional and post-translational regulatory mechanisms. In this review, we mainly focused on how cancer cells employ transcriptional and post-translational regulatory mechanisms to manipulate ARF activities to circumvent the tumor-suppressive function of ARF. We further discussed the clinical implications of ARF in human cancer.
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Sexually dimorphic tumor suppression by small mitochondrial Arf. Oncotarget 2019; 10:1235-1237. [PMID: 30815226 PMCID: PMC6383814 DOI: 10.18632/oncotarget.26651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 01/21/2019] [Indexed: 12/03/2022] Open
Abstract
Internal translational initiation of the mRNA encoding the Arf tumor suppressor yields an N-terminally truncated small Arf protein (smArf) that lacks amino acid residues required for Mdm2 binding and p53 activation. Here, we report that female, but not male, mice engineered to produce only smArf in lieu of the full-length Arf protein retain residual, sexually dimorphic tumor suppressive activity.
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PKC Dependent p14ARF Phosphorylation on Threonine 8 Drives Cell Proliferation. Sci Rep 2018; 8:7056. [PMID: 29728595 PMCID: PMC5935756 DOI: 10.1038/s41598-018-25496-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 04/24/2018] [Indexed: 01/11/2023] Open
Abstract
ARF role as tumor suppressor has been challenged in the last years by several findings of different groups ultimately showing that its functions can be strictly context dependent. We previously showed that ARF loss in HeLa cells induces spreading defects, evident as rounded morphology of depleted cells, accompanied by a decrease of phosphorylated Focal Adhesion Kinase (FAK) protein levels and anoikis. These data, together with previous finding that a PKC dependent signalling pathway can lead to ARF stabilization, led us to the hypothesis that ARF functions in cell proliferation might be regulated by phosphorylation. In line with this, we show here that upon spreading ARF is induced through PKC activation. A constitutive-phosphorylated ARF mutant on the conserved threonine 8 (T8D) is able to mediate both cell spreading and FAK activation. Finally, ARF-T8D expression confers growth advantage to cells thus leading to the intriguing hypothesis that ARF phosphorylation could be a mechanism through which pro-proliferative or anti proliferative signals could be transduced inside the cells in both physiological and pathological conditions.
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