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Zhang R, Jin J, Shi J, Hou Y. INGs are potential drug targets for cancer. J Cancer Res Clin Oncol 2017; 143:189-197. [PMID: 27544390 DOI: 10.1007/s00432-016-2219-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 08/09/2016] [Indexed: 12/11/2022]
Abstract
PURPOSE The inhibitor of growth (ING) family consists of ING1, ING2, ING3, ING4 and ING5, which function as the type II tumor suppressors. INGs regulate cell proliferation, senescence, apoptosis, differentiation, angiogenesis, DNA repair, metastasis, and invasion by multiple pathways. In addition, INGs increase cancer cell sensitivity for chemotherapy and radiotherapy, while clinical observations show that INGs are frequently lost in some types of cancers. The aim of the study was to summarize the recent progress regarding INGs regulating tumor progression. METHODS The literatures of INGs regulating tumor progression were searched and assayed. RESULTS The regulating signaling pathways of ING1, ING2, ING3 or ING4 on tumor progression were shown. The mechanisms of INGs on tumor suppression were also assayed. CONCLUSIONS This review better summarized the signaling mechanism of INGs on tumor suppression, which provides a candidate therapy strategy for cancers.
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Affiliation(s)
- Runyun Zhang
- Department of Oncology, Affiliated Wujin People's Hospital, Jiangsu University, Changzhou, 212017, People's Republic of China
- Institute of Life Sciences, Jiangsu University, Zhenjiang, 212013, People's Republic of China
| | - Jianhua Jin
- Department of Oncology, Affiliated Wujin People's Hospital, Jiangsu University, Changzhou, 212017, People's Republic of China
| | - Juanjuan Shi
- Institute of Life Sciences, Jiangsu University, Zhenjiang, 212013, People's Republic of China.
| | - Yongzhong Hou
- Department of Oncology, Affiliated Wujin People's Hospital, Jiangsu University, Changzhou, 212017, People's Republic of China.
- Institute of Life Sciences, Jiangsu University, Zhenjiang, 212013, People's Republic of China.
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LincRNA-p21 acts as a mediator of ING1b-induced apoptosis. Cell Death Dis 2015; 6:e1668. [PMID: 25741593 PMCID: PMC4385912 DOI: 10.1038/cddis.2015.15] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 01/02/2015] [Accepted: 01/07/2015] [Indexed: 02/08/2023]
Abstract
ING1b is a tumor suppressor that affects transcription, cell cycle control and apoptosis. ING1b is deregulated in disease, and its activity is closely linked to that of p53. In addition to regulating protein-coding genes, we found that ING1b also influences the expression of large intergenic non-coding RNAs (lincRNAs). In particular, lincRNA-p21 was significantly induced after DNA-damage stress or by ING1b overexpression. Furthermore, lincRNA-p21 expression in response to DNA damage was significantly attenuated in cells lacking ING1b. LincRNA-p21 is also a target of p53 and can trigger apoptosis in mouse cell models. We found that this function of lincRNA-p21 is conserved in human cell models. Moreover, ING1b and p53 could function independently to influence lincRNA-p21 expression. However, their effects become more additive under conditions of stress. In particular, ING1b regulates lincRNA-p21 levels by binding to its promoter and is required for induction of lincRNA-p21 by p53. The ability of ING1b to cause apoptosis is also impaired in the absence of lincRNA-p21. Surprisingly, deletion of the ING1b plant homeodomain, which allows it to bind histones and regulate chromatin structure, did not alter regulation of lincRNA-p21. Our findings suggest that ING1b induces lincRNA-p21 expression independently of histone 3 lysine 4 trimethylation mark recognition and that lincRNA-p21 functions downstream of ING1b. Thus, regulation at the level of lincRNA-p21 may represent the point at which ING1b and p53 pathways converge to induce apoptosis under specific stress conditions.
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Defining the minimal peptide sequence of the ING1b tumour suppressor capable of efficiently inducing apoptosis. Cell Death Discov 2015; 1:15048. [PMID: 27551477 PMCID: PMC4979497 DOI: 10.1038/cddiscovery.2015.48] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 09/08/2015] [Indexed: 02/07/2023] Open
Abstract
The ING1b protein is a type-II tumour suppressor and stoichiometric member of the Sin3 histone deacetylase (HDAC) protein complex in which it acts to target HDAC activity to regulate chromatin structure. Altering ING1 levels by ectopic expression of ING1b in cancer cells promotes apoptosis, whereas altering levels by knockout in normal murine fibroblasts alters sensitivity to doxorubicin-induced apoptosis. We have identified a minimal region of ING1b capable of inducing levels of apoptosis in targeted cells as effectively as full-length ING1b, using transient overexpression of ING1b fragments followed by the Annexin V assay. We observed high levels of apoptosis in 14 of 14 cancer cell lines tested. Infecting triple-negative tumorigenic MDA-MB-468 breast cancer, U2OS or Saos-2 cells at multiplicities of infection (MOIs) ranging from 10 to 20 rapidly triggered apoptosis in ~80% of infected cells within 48 h. This was not due to the effects of virus, as infection at the same MOI with a control adenovirus expressing GFP was not effective in inducing apoptosis. When used at low MOIs, the ING1b fragment showed a cell-killing efficacy that was higher than native, full-length ING1b. Using a doxycycline-regulated inducible p53 expression system demonstrated that apoptosis induced by the ING1b fragment was p53 independent. Given the growing importance of combination therapies, we evaluated whether there was synergism between the ING1b fragment and HDAC inhibitors. Combination treatments with TSA, LBH 589 and SAHA reduced cancer cell survival by 3.9–4.7-fold as compared with single-drug treatment, and resulted in ~90% reduction in cell survival. Normalized isobologram analysis confirmed strong synergism between the ING1b fragment and drugs tested. These findings provide support for using ING1b-derived therapeutics as adjuvant treatments in combination with existing epigenetic therapies.
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Novello C, Pazzaglia L, Conti A, Quattrini I, Pollino S, Perego P, Picci P, Benassi MS. p53-dependent activation of microRNA-34a in response to etoposide-induced DNA damage in osteosarcoma cell lines not impaired by dominant negative p53 expression. PLoS One 2014; 9:e114757. [PMID: 25490093 PMCID: PMC4260944 DOI: 10.1371/journal.pone.0114757] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 11/13/2014] [Indexed: 11/29/2022] Open
Abstract
Osteosarcoma (OS) is the most common primary malignant bone tumor and prevalently occurs in the second decade of life. Etoposide, a chemotherapeutic agent used in combined treatments of recurrent human OS, belongs to the topoisomerase inhibitor family and causes DNA breakage. In this study we evaluated the cascade of events determined by etoposide-induced DNA damage in OS cell lines with different p53 status focusing on methylation status and expression of miR-34a that modulate tumor cell growth and cell cycle progression. Wild-type p53 U2-OS cells and U2-OS cells expressing dominant-negative form of p53 (U2- OS175) were more sensitive to etoposide than p53-deficient MG63 and Saos-2 cells, showing increased levels of unmethylated miR-34a, reduced expression of CDK4 and cell cycle arrest in G1 phase. In contrast, MG63 and Saos-2 cell lines presented aberrant methylation of miR-34a promoter gene with no miR-34a induction after etoposide treatment, underlining the close connection between p53 expression and miR-34a methylation status. Consistently, in p53siRNA transfected U2-OS cells we observed loss of miR-34a induction after etoposide exposure associated with a partial gain of gene methylation and cell cycle progress towards G2/M phase. Our results suggest that the open and unmethylated conformation of the miR-34a gene may be regulated by p53 able to bind the gene promoter. In conclusion, cell response to etoposide-induced DNA damage was not compromised in cells with dominant-negative p53 expression.
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Affiliation(s)
- Chiara Novello
- Laboratory of Experimental Oncology, Rizzoli Orthopaedic Institute, Bologna, Italy
| | - Laura Pazzaglia
- Laboratory of Experimental Oncology, Rizzoli Orthopaedic Institute, Bologna, Italy
| | - Amalia Conti
- Laboratory of Experimental Oncology, Rizzoli Orthopaedic Institute, Bologna, Italy
| | - Irene Quattrini
- Laboratory of Experimental Oncology, Rizzoli Orthopaedic Institute, Bologna, Italy
| | - Serena Pollino
- Laboratory of Experimental Oncology, Rizzoli Orthopaedic Institute, Bologna, Italy
- Centre for Molecular and Translational Oncology & Department of Life Sciences- University of Parma, Parma, Italy
| | - Paola Perego
- Molecular Pharmacology Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Piero Picci
- Laboratory of Experimental Oncology, Rizzoli Orthopaedic Institute, Bologna, Italy
| | - Maria Serena Benassi
- Laboratory of Experimental Oncology, Rizzoli Orthopaedic Institute, Bologna, Italy
- * E-mail:
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5
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Keep-ING balance: tumor suppression by epigenetic regulation. FEBS Lett 2014; 588:2728-42. [PMID: 24632289 DOI: 10.1016/j.febslet.2014.03.011] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 03/06/2014] [Indexed: 12/26/2022]
Abstract
Cancer cells accumulate genetic and epigenetic changes that alter gene expression to drive tumorigenesis. Epigenetic silencing of tumor suppressor, cell cycle, differentiation and DNA repair genes contributes to neoplastic transformation. The ING (inhibitor of growth) proteins (ING1-ING5) have emerged as a versatile family of growth regulators, phospholipid effectors, histone mark sensors and core components of HDAC1/2 - and several HAT chromatin-modifying complexes. This review will describe the characteristic pathways by which ING family proteins differentially affect the Hallmarks of Cancer and highlight the various epigenetic mechanisms by which they regulate gene expression. Finally, we will discuss their potentials as biomarkers and therapeutic targets in epigenetic treatment strategies.
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Abstract
Since cancer is one of the leading causes of death worldwide, there is an urgent need to find better treatments. Currently, the use of chemotherapeutics remains the predominant option for cancer therapy. However, one of the major obstacles for successful cancer therapy using these chemotherapeutics is that patients often do not respond or eventually develop resistance after initial treatment. Therefore identification of genes involved in chemotherapeutic response is critical for predicting tumour response and treating drug-resistant cancer patients. A group of genes commonly lost or inactivated are tumour suppressor genes, which can promote the initiation and progression of cancer through regulation of various biological processes such as cell proliferation, cell death and cell migration/invasion. Recently, mounting evidence suggests that these tumour suppressor genes also play a very important role in the response of cancers to a variety of chemotherapeutic drugs. In the present review, we will provide a comprehensive overview on how major tumour suppressor genes [Rb (retinoblastoma), p53 family, cyclin-dependent kinase inhibitors, BRCA1 (breast-cancer susceptibility gene 1), PTEN (phosphatase and tensin homologue deleted on chromosome 10), Hippo pathway, etc.] are involved in chemotherapeutic drug response and discuss their applications in predicting the clinical outcome of chemotherapy for cancer patients. We also propose that tumour suppressor genes are critical chemotherapeutic targets for the successful treatment of drug-resistant cancer patients in future applications.
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Adenovirus-mediated expression of p33(ING1b) induces apoptosis and inhibits proliferation in gastric adenocarcinoma cells in vitro. Gastric Cancer 2012; 15:355-62. [PMID: 22237655 DOI: 10.1007/s10120-011-0123-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 11/26/2011] [Indexed: 02/07/2023]
Abstract
BACKGROUND Inhibitor of growth 1b (ING1b) is considered to be a class II tumor suppressor gene. Although reduced expression of p33(ING1b) has been reported in many human malignancies, including gastric cancers, the effect of p33(ING1b) on gastric cancer cells has yet to be investigated. METHODS Expression of p33(ING1b) in gastric adenocarcinoma tissues and their adjacent non-malignant gastric mucosa, as well as in gastric adenocarcinoma cell lines and normal gastric epithelial cells, was detected by using Western blotting. Recombinant adenoviruses were prepared to mediate the ectopic expression of p33(ING1b) (Ad-ING1b) and green fluorescent protein (GFP)(Ad-GFP) in the gastric adenocarcinoma cell lines, SGC-7901, MKN28, and MKN45 and the normal gastric epithelial cell line GES-1. Alterations in the proliferation and apoptosis of the cells after adenoviral infection were determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry, respectively, and cell cycle distribution was analyzed in a fluorescence-activated cell sorter. RESULTS Western blotting confirmed the reduced expression of p33(ING1b) in gastric adenocarcinoma tissues and gastric adenocarcinoma cell lines. The ectopic expression of p33(ING1b) mediated by Ad-ING1b resulted in decreased growth, increased apoptosis, and cell cycle arrest at the G1 phase in both benign and malignant gastric epithelial cells regardless of their p53 status. Addition of a p53 inhibitor, pifithrin-α, did not abolish the pro-apoptotic and cell cycle-arresting effects of p33(ING1b) in p53 wild-type cells. CONCLUSIONS Down-regulation of p33(ING1b) might play an important role in the development of gastric adenocarcinoma. Targeted local expression of p33(ING1b) may offer a promising alternative therapeutic measure for gastric cancer.
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Jafarnejad SM, Li G. Regulation of p53 by ING family members in suppression of tumor initiation and progression. Cancer Metastasis Rev 2012; 31:55-73. [PMID: 22095030 DOI: 10.1007/s10555-011-9329-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The INhibitor of Growth (ING) family is an evolutionarily conserved set of proteins, implicated in suppression of initiation and progression of cancers in various tissues. They promote cell cycle arrest, cellular senescence and apoptosis, participate in stress responses, regulate DNA replication and DNA damage responses, and inhibit cancer cell migration, invasion, and angiogenesis of the tumors. At the molecular level, ING proteins are believed to participate in chromatin remodeling and transcriptional regulation of their target genes. However, the best known function of ING proteins is their cooperation with p53 tumor suppressor protein in tumor suppression. All major isoforms of ING family members can promote the transactivition of p53 and the majority of them are shown to directly interact with p53. In addition, ING proteins are thought to interact with and modulate the function of auxiliary members of p53 pathway, such as MDM2, ARF , p300, and p21, indicating their widespread involvement in the regulation and function of this prominent tumor suppressor pathway. It seems that p53 pathway is the main mechanism by which ING proteins exert their functions. Nevertheless, regulation of other pathways which are not relevant to p53, yet important for tumorigenesis such as TGF-β and NF-κB, by ING proteins is also observed. This review summarizes the current understanding of the mutual interactions and cooperation between different members of ING family with p53 pathway and implications of this cooperation in the suppression of cancer initiation and progression.
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Affiliation(s)
- Seyed Mehdi Jafarnejad
- Department of Dermatology and Skin Science, University of British Columbia, Vancouver, BC, Canada
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9
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Mathema VB, Koh YS. Inhibitor of growth-4 mediates chromatin modification and has a suppressive effect on tumorigenesis and innate immunity. Tumour Biol 2011; 33:1-7. [PMID: 21971889 DOI: 10.1007/s13277-011-0249-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 09/23/2011] [Indexed: 10/17/2022] Open
Abstract
Inhibitor of growth-4 (ING4) is a member of the ING family and acts as a tumor suppressor protein. ING4 is a promising candidate for cancer research due to its anti-angiogenic function and its role in the inhibition of cell migration, cell cycle, and induction of apoptosis. Interaction of this protein with the histone acetyl transferase complex plays a vital role in the regulation of multiple nuclear factor kappa light chain enhancer of activated B cells response elements and thus in the regulation of innate immunity. Splice variants of ING4 have different binding affinities to target sites, which results in the enhancement of its functional diversity. ING4 is among the few known regulatory proteins that can directly interact with chromatin as well as with transcription factors. The influence of ING4 on tumor necrosis factor-α, keratinocyte chemoattractant, interleukin (IL)-6, IL-8, matrix metalloproteinases, cyclooxygenase-2, and IκBα expression clearly demonstrates its critical role in the regulation of inflammatory mediators. Its interaction with liprin α1 and p53 contribute to mitigate cell spreading and induce apoptosis of cancer cells. Multiple factors including breast cancer melanoma suppressor-1 are upstream regulators of ING4 and are frequently deactivated in tumor cells. In the present review, the different properties of ING4 are discussed, and its activities are correlated with different aspects of cell physiology. Special emphasis is placed on our current understanding of ING4 with respect to its influence on chromatin modification, tumorigenesis, and innate immunity.
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Affiliation(s)
- Vivek Bhakta Mathema
- Department of Microbiology and Immunology, School of Medicine, Jeju National University, 102 Jejudaehakno, Jeju 690-756, South Korea
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10
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Xu L, Liu JT, Liu N, Lu PP, Pang XM. Effects of Panax notoginseng saponins on proliferation and apoptosis of vascular smooth muscle cells. JOURNAL OF ETHNOPHARMACOLOGY 2011; 137:226-230. [PMID: 21619919 DOI: 10.1016/j.jep.2011.05.020] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Revised: 05/10/2011] [Accepted: 05/11/2011] [Indexed: 05/30/2023]
Abstract
AIM OF THE STUDY Atherosclerosis is a common cardiovascular disease, and linked with the development of many cardiovascular complications, such as myocardial ischemia and stroke. Although pathogenesis of atherosclerosis is not completely elucidated, increasing evidence has demonstrated that abnormal proliferation of vascular smooth muscle cells (VSMCs) plays an important role in formation of atherosclerosis. Previous studies showed that saponins from Panax notoginseng (PNS) possess anti-atherosclerotic properties. However, the mechanism of PNS against atherosclerosis is not well understood. Therefore, the present study observed the effects of PNS on proliferation and apoptosis of VSMCs. MATERIALS AND METHODS Rat VSMCs were cultured, and platelet-derived growth factor (PDGF) was used to stimulate cell proliferation. The viability of VSMCs was assessed with the MTT method. VSMCs apoptosis was detected by flow cytometry. Expressions of apoptosis related protein p53, Bax, caspase-3 and Bcl-2 were determined using Western blot. RESULTS Pretreatment of the cells with PNS (200, 400, 800 μg/mL) significantly inhibited proliferation of PDGF-stimulated VSMCs, and induced apoptosis of the proliferated VSMCs in a concentration-dependent way. Western blot analysis showed that PNS upregulated expressions of pro-apoptotic protein p53, Bax and caspase-3, downregulated expression of anti-apoptotic protein Bcl-2, and enlarged Bax/Bcl-2 ratio in the proliferated VSMCs induced by PDGF. CONCLUSIONS This study demonstrates that PNS both inhibits VSMCs proliferation and induces VSMCs apoptosis through upregulating p53, Bax, caspase-3 expressions and downregulating Bcl-2 expression, which constitute the pharmacological basis of its anti-atherosclerotic action.
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MESH Headings
- Animals
- Apoptosis/drug effects
- Blotting, Western
- Cardiovascular Agents/isolation & purification
- Cardiovascular Agents/pharmacology
- Caspase 3/metabolism
- Cell Proliferation/drug effects
- Cell Survival/drug effects
- Cells, Cultured
- Dose-Response Relationship, Drug
- Flow Cytometry
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Myocytes, Smooth Muscle/pathology
- Panax notoginseng/chemistry
- Plant Extracts/isolation & purification
- Plant Extracts/pharmacology
- Platelet-Derived Growth Factor/metabolism
- Proto-Oncogene Proteins c-bcl-2/metabolism
- Rats
- Rats, Sprague-Dawley
- Saponins/isolation & purification
- Saponins/pharmacology
- Time Factors
- Tumor Suppressor Protein p53/metabolism
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Affiliation(s)
- Li Xu
- Department of Pharmacology, Xi'an Jiaotong University School of Medicine, Xi'an 710061, China
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COLES ANDREWH, JONES STEPHENN. The ING gene family in the regulation of cell growth and tumorigenesis. J Cell Physiol 2009; 218:45-57. [PMID: 18780289 PMCID: PMC2872195 DOI: 10.1002/jcp.21583] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The five members of the inhibitor of growth (ING) gene family have garnered significant interest due to their putative roles as tumor suppressors. However, the precise role(s) of these ING proteins in regulating cell growth and tumorigenesis remains uncertain. Biochemical and molecular biological analysis has revealed that all ING members encode a PHD finger motif proposed to bind methylated histones and phosphoinosital, and all ING proteins have been found as components of large chromatin remodeling complexes that also include histone acetyl transferase (HAT) and histone deacetylase (HDAC) enzymes, suggesting a role for ING proteins in regulating gene transcription. Additionally, the results of forced overexpression studies performed in tissue culture have indicated that several of the ING proteins can interact with the p53 tumor suppressor protein and/or the nuclear factor-kappa B (NF-kappaB) protein complex. As these ING-associated proteins play well-established roles in numerous cell processes, including DNA repair, cell growth and survival, inflammation, and tumor suppression, several models have been proposed that ING proteins act as key regulators of cell growth not only through their ability to modify gene transcription but also through their ability to alter p53 and NF-kappaB activity. However, these models have yet to be substantiated by in vivo experimentation. This review summarizes what is currently known about the biological functions of the five ING genes based upon in vitro experiments and recent mouse modeling efforts, and will highlight the potential impact of INGs on the development of cancer.
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Affiliation(s)
- ANDREW H. COLES
- Department of Cell Biology, University of Massachusetts Medical School, Worcester, Massachusetts
| | - STEPHEN N. JONES
- Department of Cell Biology, University of Massachusetts Medical School, Worcester, Massachusetts
- Department of Cancer Biology, University of Massachusetts Medical School, Worcester, Massachusetts
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The Caenorhabditis elegans ing-3 gene regulates ionizing radiation-induced germ-cell apoptosis in a p53-associated pathway. Genetics 2008; 181:473-82. [PMID: 19015549 DOI: 10.1534/genetics.107.080515] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The inhibitor of growth (ING) family of type II tumor suppressors are encoded by five genes in mammals and by three genes in Caenorhabditis elegans. All ING proteins contain a highly conserved plant homeodomain (PHD) zinc finger. ING proteins are activated by stresses, including ionizing radiation, leading to the activation of p53. ING proteins in mammals and yeast have recently been shown to read the histone code in a methylation-sensitive manner to regulate gene expression. Here we identify and characterize ing-3, the C. elegans gene with the highest sequence identity to the human ING3 gene. ING-3 colocalizes with chromatin in embryos, the germline, and somatic cells. The ing-3 gene is part of an operon but is also transcribed from its own promoter. Both ing-3(RNAi) and ing-3 mutant strains demonstrate that the gene likely functions in concert with the C. elegans p53 homolog, cep-1, to induce germ-cell apoptosis in response to ionizing radiation. Somatically, the ing-3 mutant has a weak kinker uncoordinated (kinker Unc) phenotype, indicating a possible neuronal function.
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13
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Soliman MA, Riabowol K. After a decade of study-ING, a PHD for a versatile family of proteins. Trends Biochem Sci 2007; 32:509-19. [PMID: 17949986 DOI: 10.1016/j.tibs.2007.08.006] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2007] [Revised: 08/14/2007] [Accepted: 08/14/2007] [Indexed: 01/03/2023]
Abstract
The INhibitor of Growth (ING) family of type II tumour suppressors are encoded by five genes in mammals (ING1-ING5), most of which encode multiple isoforms via splicing, and all of which contain a highly conserved plant homeodomain (PHD) finger motif. Since their discovery approximately ten years ago, significant progress has been made in understanding their subcellular targeting, their relationship to p53, their activation by bioactive phospholipids, and their key role in reading the histone code via PHD fingers, with subsequent effects on histone acetylation and transcriptional regulation. In the past year, we have begun to understand how ING proteins integrate stress signals with interpretation and modification of the histone epigenetic code to function as tumour suppressors.
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Affiliation(s)
- Mohamed A Soliman
- Department of Biochemistry University of Calgary, 3330 Hospital Drive N.W., Calgary, Alberta T2N 4N1, Canada
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Dass CR, Ek ETH, Choong PFM. Human xenograft osteosarcoma models with spontaneous metastasis in mice: clinical relevance and applicability for drug testing. J Cancer Res Clin Oncol 2006; 133:193-8. [PMID: 17031670 DOI: 10.1007/s00432-006-0157-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2006] [Accepted: 08/28/2006] [Indexed: 10/24/2022]
Abstract
Osteosarcoma cells derived from patients have been isolated and subsequently cultured for the past 35 years. To date though, there have been no major breakthroughs in the development of a model for osteosarcoma that uses orthotopic implantation of human osteosarcoma cells and that closely emulates the clinical progression of this debilitating and fatal disease. Such a model is long overdue given the devastating demographics (second highest cause of cancer-related death in the paediatric age group) of the ailment and the lack of solid options for control, if not cure, for the disease, as it also is the most common primary tumour of bone. Only then can more robust R & D be undertaken in the search for efficacious anti-osteosarcoma agents. This review tackles this conundrum and lists the variety of models (that use human osteosarcoma cells) available and the types of studies performed with these.
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Affiliation(s)
- Crispin R Dass
- Department of Orthopaedics, University of Melbourne, St. Vincent's Hospital, Fitzroy, VIC 3065, Australia.
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