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Csergeová L, Krbušek D, Janoštiak R. CIP/KIP and INK4 families as hostages of oncogenic signaling. Cell Div 2024; 19:11. [PMID: 38561743 PMCID: PMC10985988 DOI: 10.1186/s13008-024-00115-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 03/25/2024] [Indexed: 04/04/2024] Open
Abstract
CIP/KIP and INK4 families of Cyclin-dependent kinase inhibitors (CKIs) are well-established cell cycle regulatory proteins whose canonical function is binding to Cyclin-CDK complexes and altering their function. Initial experiments showed that these proteins negatively regulate cell cycle progression and thus are tumor suppressors in the context of molecular oncology. However, expanded research into the functions of these proteins showed that most of them have non-canonical functions, both cell cycle-dependent and independent, and can even act as tumor enhancers depending on their posttranslational modifications, subcellular localization, and cell state context. This review aims to provide an overview of canonical as well as non-canonical functions of CIP/KIP and INK4 families of CKIs, discuss the potential avenues to promote their tumor suppressor functions instead of tumor enhancing ones, and how they could be utilized to design improved treatment regimens for cancer patients.
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Affiliation(s)
- Lucia Csergeová
- BIOCEV-First Faculty of Medicine, Charles University, Prague, Czechia
| | - David Krbušek
- BIOCEV-First Faculty of Medicine, Charles University, Prague, Czechia
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2
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Yin BK, Wang ZQ. Beyond HAT Adaptor: TRRAP Liaisons with Sp1-Mediated Transcription. Int J Mol Sci 2021; 22:12445. [PMID: 34830324 PMCID: PMC8625110 DOI: 10.3390/ijms222212445] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 11/09/2021] [Accepted: 11/15/2021] [Indexed: 12/19/2022] Open
Abstract
The members of the phosphatidylinositol 3-kinase-related kinase (PIKK) family play vital roles in multiple biological processes, including DNA damage response, metabolism, cell growth, mRNA decay, and transcription. TRRAP, as the only member lacking the enzymatic activity in this family, is an adaptor protein for several histone acetyltransferase (HAT) complexes and a scaffold protein for multiple transcription factors. TRRAP has been demonstrated to regulate various cellular functions in cell cycle progression, cell stemness maintenance and differentiation, as well as neural homeostasis. TRRAP is known to be an important orchestrator of many molecular machineries in gene transcription by modulating the activity of some key transcription factors, including E2F1, c-Myc, p53, and recently, Sp1. This review summarizes the biological and biochemical studies on the action mode of TRRAP together with the transcription factors, focusing on how TRRAP-HAT mediates the transactivation of Sp1-governing biological processes, including neurodegeneration.
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Affiliation(s)
- Bo-Kun Yin
- Leibniz Institute on Aging-Fritz Lipmann Institute (FLI), 07745 Jena, Germany;
| | - Zhao-Qi Wang
- Leibniz Institute on Aging-Fritz Lipmann Institute (FLI), 07745 Jena, Germany;
- Faculty of Biological Sciences, Friedrich Schiller University Jena, 07743 Jena, Germany
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3
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Kang DW, Hwang WC, Noh YN, Park KS, Min DS. Phospholipase D1 inhibition sensitizes glioblastoma to temozolomide and suppresses its tumorigenicity. J Pathol 2020; 252:304-316. [PMID: 32725633 PMCID: PMC7693208 DOI: 10.1002/path.5519] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 06/12/2020] [Accepted: 07/24/2020] [Indexed: 12/15/2022]
Abstract
Resistance of glioblastoma to the chemotherapeutic compound temozolomide is associated with the presence of glioblastoma stem cells in glioblastoma and is a key obstacle for the poor prognosis of glioblastoma. Here, we show that phospholipase D1 is elevated in CD44High glioblastoma stem cells and in glioblastoma, especially recurring glioblastoma. Phospholipase D1 elevation positively correlated with the level of CD44 and poor prognosis in glioblastoma patients. Temozolomide significantly upregulated the expression of phospholipase D1 in the low and moderate CD44 populations of glioblastoma stem cells, but not in the CD44High population in which phospholipase D1 is highly expressed. Phospholipase D1 conferred resistance to temozolomide in CD44High glioblastoma stem cells and increased their self‐renewal capacity and maintenance. Phospholipase D1 expression significantly correlated with levels of temozolomide resistance factors, which were suppressed by microRNA‐320a and ‐4496 induced by phospholipase D1 inhibition. Genetic and pharmacological targeting of phospholipase D1 attenuated glioblastoma stem cell‐derived intracranial tumors of glioblastoma using the microRNAs, and improved survival. Treatment solely with temozolomide produced no benefits on the glioblastoma, whereas in combination, phospholipase D1 inhibition sensitized glioblastoma stem cells to temozolomide and reduced glioblastoma tumorigenesis. Together, these findings indicate that phospholipase D1 inhibition might overcome resistance to temozolomide and represents a potential treatment strategy for glioblastoma. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.
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Affiliation(s)
- Dong Woo Kang
- Department of Molecular Biology, College of Natural Science, Pusan National University, Busan, Republic of Korea
| | - Won Chan Hwang
- Department of Molecular Biology, College of Natural Science, Pusan National University, Busan, Republic of Korea.,College of Pharmacy, Yonsei University, Incheon, Republic of Korea
| | - Yu Na Noh
- Asan Institute for Life Science, Asan Medical Center, Seoul, Republic of Korea
| | - Kang Seo Park
- Asan Institute for Life Science, Asan Medical Center, Seoul, Republic of Korea.,Department of Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Do Sik Min
- College of Pharmacy, Yonsei University, Incheon, Republic of Korea
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Bucha S, Mukhopadhyay D, Bhattacharyya NP. E2F1 activates MFN2 expression by binding to the promoter and decreases mitochondrial fission and mitophagy in HeLa cells. FEBS J 2019; 286:4525-4541. [DOI: 10.1111/febs.14980] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 07/01/2019] [Accepted: 07/02/2019] [Indexed: 12/19/2022]
Affiliation(s)
- Sudha Bucha
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics HBNI Kolkata India
| | - Debashis Mukhopadhyay
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics HBNI Kolkata India
| | - Nitai Pada Bhattacharyya
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics HBNI Kolkata India
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Gasri-Plotnitsky L, Ovadia A, Shamalov K, Nizri-Megnaji T, Meir S, Zurer I, Cohen CJ, Ginsberg D. A novel lncRNA, GASL1, inhibits cell proliferation and restricts E2F1 activity. Oncotarget 2017; 8:23775-23786. [PMID: 28423601 PMCID: PMC5410343 DOI: 10.18632/oncotarget.15864] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 02/10/2017] [Indexed: 01/23/2023] Open
Abstract
The human genome encodes thousands of unique long non-coding RNAs (lncRNAs), many of which are emerging as critical regulators of cell fate. However, their functions as well as their transcriptional regulation are only partially understood. The E2F1 transcription factor induces both proliferation and apoptosis, and is a critical downstream target of the tumor suppressor, RB. Here, we provide evidence that a novel lncRNA named GASL1 is transcriptionally regulated by E2F1; GASL1 levels are elevated upon activation of exogenous E2F1 or endogenous E2Fs. Inhibition of GASL1 expression induced cell cycle progression, and in particular, G1 exit. Moreover, GASL1 silencing enhanced cell proliferation, while, conversely, its ectopic expression inhibited proliferation. Knockdown of GASL1 also enhanced E2F1-induced apoptosis, suggesting the existence of an E2F/GASL1 negative feedback loop. In agreement with this notion, silencing of GASL1 led to increased levels of phosphorylated pRB and loss of Rb impaired the effect of GASL1 silencing on G1 exit. Importantly, xenograft experiments demonstrated that GASL1 deletion enhances tumor growth. Moreover, low levels of GASL1 are associated with decreased survival of liver cancer patients. Taken together, our data identify GASL1 as a novel lncRNA regulator of cell cycle progression and cell proliferation with a potential role in cancer.
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Affiliation(s)
- Lital Gasri-Plotnitsky
- The Mina and Everard Goodman Faculty of Life Science, Bar Ilan University, Ramat Gan 52900, Israel
| | - Aviv Ovadia
- The Mina and Everard Goodman Faculty of Life Science, Bar Ilan University, Ramat Gan 52900, Israel
| | - Katerina Shamalov
- The Mina and Everard Goodman Faculty of Life Science, Bar Ilan University, Ramat Gan 52900, Israel
| | - Tali Nizri-Megnaji
- The Mina and Everard Goodman Faculty of Life Science, Bar Ilan University, Ramat Gan 52900, Israel
| | - Shimrit Meir
- The Mina and Everard Goodman Faculty of Life Science, Bar Ilan University, Ramat Gan 52900, Israel
| | - Irit Zurer
- The Mina and Everard Goodman Faculty of Life Science, Bar Ilan University, Ramat Gan 52900, Israel
| | - Cyrille J Cohen
- The Mina and Everard Goodman Faculty of Life Science, Bar Ilan University, Ramat Gan 52900, Israel
| | - Doron Ginsberg
- The Mina and Everard Goodman Faculty of Life Science, Bar Ilan University, Ramat Gan 52900, Israel
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p53-related protein kinase confers poor prognosis and represents a novel therapeutic target in multiple myeloma. Blood 2017; 129:1308-1319. [PMID: 28082445 DOI: 10.1182/blood-2016-09-738500] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 12/28/2016] [Indexed: 12/26/2022] Open
Abstract
p53-related protein kinase (TP53RK, also known as PRPK) is an upstream kinase that phosphorylates (serine residue Ser15) and mediates p53 activity. Here we show that TP53RK confers poor prognosis in multiple myeloma (MM) patients, and, conversely, that TP53RK knockdown inhibits p53 phosphorylation and triggers MM cell apoptosis, associated with downregulation of c-Myc and E2F-1-mediated upregulation of pro-apoptotic Bim. We further demonstrate that TP53RK downregulation also triggers growth inhibition in p53-deficient and p53-mutant MM cell lines and identify novel downstream targets of TP53RK including ribonucleotide reductase-1, telomerase reverse transcriptase, and cyclin-dependent kinase inhibitor 2C. Our previous studies showed that immunomodulatory drugs (IMiDs) downregulate p21 and trigger apoptosis in wild-type-p53 MM.1S cells, Importantly, we demonstrate by pull-down, nuclear magnetic resonance spectroscopy, differential scanning fluorimetry, and isothermal titration calorimetry that IMiDs bind and inhibit TP53RK, with biologic sequelae similar to TP53RK knockdown. Our studies therefore demonstrate that either genetic or pharmacological inhibition of TP53RK triggers MM cell apoptosis via both p53-Myc axis-dependent and axis-independent pathways, validating TP53RK as a novel therapeutic target in patients with poor-prognosis MM.
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Acevedo-Luna N, Mariño-Ramírez L, Halbert A, Hansen U, Landsman D, Spouge JL. Most of the tight positional conservation of transcription factor binding sites near the transcription start site reflects their co-localization within regulatory modules. BMC Bioinformatics 2016; 17:479. [PMID: 27871221 PMCID: PMC5117513 DOI: 10.1186/s12859-016-1354-5] [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: 05/31/2016] [Accepted: 11/11/2016] [Indexed: 11/24/2022] Open
Abstract
Background Transcription factors (TFs) form complexes that bind regulatory modules (RMs) within DNA, to control specific sets of genes. Some transcription factor binding sites (TFBSs) near the transcription start site (TSS) display tight positional preferences relative to the TSS. Furthermore, near the TSS, RMs can co-localize TFBSs with each other and the TSS. The proportion of TFBS positional preferences due to TFBS co-localization within RMs is unknown, however. ChIP experiments confirm co-localization of some TFBSs genome-wide, including near the TSS, but they typically examine only a few TFs at a time, using non-physiological conditions that can vary from lab to lab. In contrast, sequence analysis can examine many TFs uniformly and methodically, broadly surveying the co-localization of TFBSs with tight positional preferences relative to the TSS. Results Our statistics found 43 significant sets of human motifs in the JASPAR TF Database with positional preferences relative to the TSS, with 38 preferences tight (±5 bp). Each set of motifs corresponded to a gene group of 135 to 3304 genes, with 42/43 (98%) gene groups independently validated by DAVID, a gene ontology database, with FDR < 0.05. Motifs corresponding to two TFBSs in a RM should co-occur more than by chance alone, enriching the intersection of the gene groups corresponding to the two TFs. Thus, a gene-group intersection systematically enriched beyond chance alone provides evidence that the two TFs participate in an RM. Of the 903 = 43*42/2 intersections of the 43 significant gene groups, we found 768/903 (85%) pairs of gene groups with significantly enriched intersections, with 564/768 (73%) intersections independently validated by DAVID with FDR < 0.05. A user-friendly web site at http://go.usa.gov/3kjsH permits biologists to explore the interaction network of our TFBSs to identify candidate subunit RMs. Conclusions Gene duplication and convergent evolution within a genome provide obvious biological mechanisms for replicating an RM near the TSS that binds a particular TF subunit. Of all intersections of our 43 significant gene groups, 85% were significantly enriched, with 73% of the significant enrichments independently validated by gene ontology. The co-localization of TFBSs within RMs therefore likely explains much of the tight TFBS positional preferences near the TSS. Electronic supplementary material The online version of this article (doi:10.1186/s12859-016-1354-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Natalia Acevedo-Luna
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, 50011, USA
| | - Leonardo Mariño-Ramírez
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, 20894, USA
| | - Armand Halbert
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, 20894, USA
| | - Ulla Hansen
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA, 02215, USA
| | - David Landsman
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, 20894, USA
| | - John L Spouge
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, 20894, USA.
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Li Y, Min W, Li M, Han G, Dai D, Zhang L, Chen X, Wang X, Zhang Y, Yue Z, Liu J. Identification of hub genes and regulatory factors of glioblastoma multiforme subgroups by RNA-seq data analysis. Int J Mol Med 2016; 38:1170-8. [PMID: 27572852 PMCID: PMC5029949 DOI: 10.3892/ijmm.2016.2717] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 08/04/2016] [Indexed: 11/24/2022] Open
Abstract
Glioblastoma multiforme (GBM) is the most common malignant brain tumor. This study aimed to identify the hub genes and regulatory factors of GBM subgroups by RNA sequencing (RNA-seq) data analysis, in order to explore the possible mechanisms responsbile for the progression of GBM. The dataset RNASeqV2 was downloaded by TCGA-Assembler, containing 169 GBM and 5 normal samples. Gene expression was calculated by the reads per kilobase per million reads measurement, and nor malized with tag count comparison. Following subgroup classification by the non-negative matrix factorization, the differentially expressed genes (DEGs) were screened in 4 GBM subgroups using the method of significance analysis of microarrays. Functional enrichment analysis was performed by DAVID, and the protein-protein interaction (PPI) network was constructed based on the HPRD database. The subgroup-related microRNAs (miRNAs or miRs), transcription factors (TFs) and small molecule drugs were predicted with predefined criteria. A cohort of 19,515 DEGs between the GBM and control samples was screened, which were predominantly enriched in cell cycle- and immunoreaction-related pathways. In the PPI network, lymphocyte cytosolic protein 2 (LCP2), breast cancer 1 (BRCA1), specificity protein 1 (Sp1) and chromodomain-helicase-DNA-binding protein 3 (CHD3) were the hub nodes in subgroups 1–4, respectively. Paired box 5 (PAX5), adipocyte protein 2 (aP2), E2F transcription factor 1 (E2F1) and cAMP-response element-binding protein-1 (CREB1) were the specific TFs in subgroups 1–4, respectively. miR-147b, miR-770-5p, miR-220a and miR-1247 were the particular miRNAs in subgroups 1–4, respectively. Natalizumab was the predicted small molecule drug in subgroup 2. In conclusion, the molecular regulatory mechanisms of GBM pathogenesis were distinct in the different subgroups. Several crucial genes, TFs, miRNAs and small molecules in the different GBM subgroups were identified, which may be used as potential markers. However, further experimental validations may be required.
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Affiliation(s)
- Yanan Li
- Department of Neurosurgery, Changhai Hospital, The Second Military Medical University, Shanghai 200433, P.R. China
| | - Weijie Min
- Department of Neurosurgery, Changhai Hospital, The Second Military Medical University, Shanghai 200433, P.R. China
| | - Mengmeng Li
- Department of Rheumatology and Immunology, Shanghai Changzheng Hospital, The Second Military Medical University, Shanghai 200003, P.R. China
| | - Guosheng Han
- Department of Neurosurgery, Changhai Hospital, The Second Military Medical University, Shanghai 200433, P.R. China
| | - Dongwei Dai
- Department of Neurosurgery, Changhai Hospital, The Second Military Medical University, Shanghai 200433, P.R. China
| | - Lei Zhang
- Department of Neurosurgery, Changhai Hospital, The Second Military Medical University, Shanghai 200433, P.R. China
| | - Xin Chen
- Department of Neurosurgery, Changhai Hospital, The Second Military Medical University, Shanghai 200433, P.R. China
| | - Xinglai Wang
- Department of Neurosurgery, Changhai Hospital, The Second Military Medical University, Shanghai 200433, P.R. China
| | - Yuhui Zhang
- Department of Neurosurgery, Changhai Hospital, The Second Military Medical University, Shanghai 200433, P.R. China
| | - Zhijian Yue
- Department of Neurosurgery, Changhai Hospital, The Second Military Medical University, Shanghai 200433, P.R. China
| | - Jianmin Liu
- Department of Neurosurgery, Changhai Hospital, The Second Military Medical University, Shanghai 200433, P.R. China
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DNA methyltransferase 3A promotes cell proliferation by silencing CDK inhibitor p18INK4C in gastric carcinogenesis. Sci Rep 2015; 5:13781. [PMID: 26350239 PMCID: PMC4563369 DOI: 10.1038/srep13781] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 08/05/2015] [Indexed: 01/13/2023] Open
Abstract
Little is known about the roles of DNA methyltransferase 3A (DNMT3A) in gastric carcinogenesis. Here, we reported that the exogenous expression of DNMT3A promoted gastric cancer (GC) cell proliferation by accelerating the G1/S transition. Subsequently, p18INK4C was identified as a downstream target of DNMT3A. The elevated expression of DNMT3A suppressed p18INK4C at least at the transcriptional level. Depletion of p18INK4C expression in GC cells induced cell cycle progression, whereas its re-expression alleviated the effect of DNMT3A overexpression on G1/S transition. Furthermore, we found that DNMT3A modulated p18INK4C by directly binding to and silencing the p18INK4C gene via promoter hypermethylation. In clinical GC tissue specimens analyzed, the level of methylation of p18INK4C detected in tumor tissues was significantly higher than that in paired non-tumor tissues. Moreover, elevated level of DNMT3A expression was associated with the differentiation of GC tissues and was negatively correlated with the p18INK4C expression level. Taken together, our results found that DNMT3A contributes to the dysregulation of the cell cycle by repressing p18INK4C in a DNA methylation-dependent manner, suggesting that DNMT3A-p18INK4C axis involved in GC. These findings provide new insights into gastric carcinogenesis and a potential therapeutic target for GC that may be further investigated in the future.
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Landrieu I, Verger A, Baert JL, Rucktooa P, Cantrelle FX, Dewitte F, Ferreira E, Lens Z, Villeret V, Monté D. Characterization of ERM transactivation domain binding to the ACID/PTOV domain of the Mediator subunit MED25. Nucleic Acids Res 2015; 43:7110-21. [PMID: 26130716 PMCID: PMC4538835 DOI: 10.1093/nar/gkv650] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 05/28/2015] [Indexed: 01/12/2023] Open
Abstract
The N-terminal acidic transactivation domain (TAD) of ERM/ETV5 (ERM38–68), a PEA3 group member of Ets-related transcription factors, directly interacts with the ACID/PTOV domain of the Mediator complex subunit MED25. Molecular details of this interaction were investigated using nuclear magnetic resonance (NMR) spectroscopy. The TAD is disordered in solution but has a propensity to adopt local transient secondary structure. We show that it folds upon binding to MED25 and that the resulting ERM–MED25 complex displays characteristics of a fuzzy complex. Mutational analysis further reveals that two aromatic residues in the ERM TAD (F47 and W57) are involved in the binding to MED25 and participate in the ability of ERM TAD to activate transcription. Mutation of a key residue Q451 in the VP16 H1 binding pocket of MED25 affects the binding of ERM. Furthermore, competition experiments show that ERM and VP16 H1 share a common binding interface on MED25. NMR data confirms the occupancy of this binding pocket by ERM TAD. Based on these experimental data, a structural model of a functional interaction is proposed. This study provides mechanistic insights into the Mediator–transactivator interactions.
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Affiliation(s)
- Isabelle Landrieu
- CNRS UMR 8576, Université de Lille, Parc CNRS de la Haute Borne, 50 avenue de Halley, B.P. 70478, 59658 Villeneuve d'Ascq Cedex, France
| | - Alexis Verger
- CNRS UMR 8576, Université de Lille, Parc CNRS de la Haute Borne, 50 avenue de Halley, B.P. 70478, 59658 Villeneuve d'Ascq Cedex, France
| | - Jean-Luc Baert
- CNRS UMR 8576, Université de Lille, Parc CNRS de la Haute Borne, 50 avenue de Halley, B.P. 70478, 59658 Villeneuve d'Ascq Cedex, France
| | - Prakash Rucktooa
- CNRS UMR 8576, Université de Lille, Parc CNRS de la Haute Borne, 50 avenue de Halley, B.P. 70478, 59658 Villeneuve d'Ascq Cedex, France
| | - François-Xavier Cantrelle
- CNRS UMR 8576, Université de Lille, Parc CNRS de la Haute Borne, 50 avenue de Halley, B.P. 70478, 59658 Villeneuve d'Ascq Cedex, France
| | - Frédérique Dewitte
- CNRS UMR 8576, Université de Lille, Parc CNRS de la Haute Borne, 50 avenue de Halley, B.P. 70478, 59658 Villeneuve d'Ascq Cedex, France
| | - Elisabeth Ferreira
- CNRS UMR 8576, Université de Lille, Parc CNRS de la Haute Borne, 50 avenue de Halley, B.P. 70478, 59658 Villeneuve d'Ascq Cedex, France
| | - Zoé Lens
- CNRS UMR 8576, Université de Lille, Parc CNRS de la Haute Borne, 50 avenue de Halley, B.P. 70478, 59658 Villeneuve d'Ascq Cedex, France
| | - Vincent Villeret
- CNRS UMR 8576, Université de Lille, Parc CNRS de la Haute Borne, 50 avenue de Halley, B.P. 70478, 59658 Villeneuve d'Ascq Cedex, France
| | - Didier Monté
- CNRS UMR 8576, Université de Lille, Parc CNRS de la Haute Borne, 50 avenue de Halley, B.P. 70478, 59658 Villeneuve d'Ascq Cedex, France
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Julian LM, Blais A. Transcriptional control of stem cell fate by E2Fs and pocket proteins. Front Genet 2015; 6:161. [PMID: 25972892 PMCID: PMC4412126 DOI: 10.3389/fgene.2015.00161] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2014] [Accepted: 04/08/2015] [Indexed: 01/04/2023] Open
Abstract
E2F transcription factors and their regulatory partners, the pocket proteins (PPs), have emerged as essential regulators of stem cell fate control in a number of lineages. In mammals, this role extends from both pluripotent stem cells to those encompassing all embryonic germ layers, as well as extra-embryonic lineages. E2F/PP-mediated regulation of stem cell decisions is highly evolutionarily conserved, and is likely a pivotal biological mechanism underlying stem cell homeostasis. This has immense implications for organismal development, tissue maintenance, and regeneration. In this article, we discuss the roles of E2F factors and PPs in stem cell populations, focusing on mammalian systems. We discuss emerging findings that position the E2F and PP families as widespread and dynamic epigenetic regulators of cell fate decisions. Additionally, we focus on the ever expanding landscape of E2F/PP target genes, and explore the possibility that E2Fs are not simply regulators of general ‘multi-purpose’ cell fate genes but can execute tissue- and cell type-specific gene regulatory programs.
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Affiliation(s)
- Lisa M Julian
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON Canada
| | - Alexandre Blais
- Ottawa Institute of Systems Biology, Ottawa, ON Canada ; Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON Canada
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12
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Shi L, Li M, Lin Q, Qi X, Su B. Functional divergence of the brain-size regulating gene MCPH1 during primate evolution and the origin of humans. BMC Biol 2013; 11:62. [PMID: 23697381 PMCID: PMC3674976 DOI: 10.1186/1741-7007-11-62] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 05/09/2013] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND One of the key genes that regulate human brain size, MCPH1 has evolved under strong Darwinian positive selection during the evolution of primates. During this evolution, the divergence of MCPH1 protein sequences among primates may have caused functional changes that contribute to brain enlargement. RESULTS To test this hypothesis, we used co-immunoprecipitation and reporter gene assays to examine the activating and repressing effects of MCPH1 on a set of its down-stream genes and then compared the functional outcomes of a series of mutant MCPH1 proteins that carry mutations at the human- and great-ape-specific sites. The results demonstrate that the regulatory effects of human MCPH1 and rhesus macaque MCPH1 are different in three of eight down-stream genes tested (p73, cyclinE1 and p14ARF), suggesting a functional divergence of MCPH1 between human and non-human primates. Further analyses of the mutant MCPH1 proteins indicated that most of the human-specific mutations could change the regulatory effects on the down-stream genes. A similar result was also observed for one of the four great-ape-specific mutations. CONCLUSIONS Collectively, we propose that during primate evolution in general and human evolution in particular, the divergence of MCPH1 protein sequences under Darwinian positive selection led to functional modifications, providing a possible molecular mechanism of how MCPH1 contributed to brain enlargement during primate evolution and human origin.
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Affiliation(s)
- Lei Shi
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, 32 East Jiao-Chang Road, Kunming, Yunnan 650223, PR China
| | - Ming Li
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, 32 East Jiao-Chang Road, Kunming, Yunnan 650223, PR China
- University of the Chinese Academy of Sciences, No.19A Yuquan Road, Shijingshan District, Beijing, 100049, China
| | - Qiang Lin
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, 32 East Jiao-Chang Road, Kunming, Yunnan 650223, PR China
- University of the Chinese Academy of Sciences, No.19A Yuquan Road, Shijingshan District, Beijing, 100049, China
| | - Xuebin Qi
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, 32 East Jiao-Chang Road, Kunming, Yunnan 650223, PR China
| | - Bing Su
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, 32 East Jiao-Chang Road, Kunming, Yunnan 650223, PR China
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13
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Verger A, Baert JL, Verreman K, Dewitte F, Ferreira E, Lens Z, de Launoit Y, Villeret V, Monté D. The Mediator complex subunit MED25 is targeted by the N-terminal transactivation domain of the PEA3 group members. Nucleic Acids Res 2013; 41:4847-59. [PMID: 23531547 PMCID: PMC3643604 DOI: 10.1093/nar/gkt199] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
PEA3, ERM and ER81 belong to the PEA3 subfamily of Ets transcription factors and play important roles in a number of tissue-specific processes. Transcriptional activation by PEA3 subfamily factors requires their characteristic amino-terminal acidic transactivation domain (TAD). However, the cellular targets of this domain remain largely unknown. Using ERM as a prototype, we show that the minimal N-terminal TAD activates transcription by contacting the activator interacting domain (ACID)/Prostate tumor overexpressed protein 1 (PTOV) domain of the Mediator complex subunit MED25. We further show that depletion of MED25 disrupts the association of ERM with the Mediator in vitro. Small interfering RNA-mediated knockdown of MED25 as well as the overexpression of MED25-ACID and MED25-VWA domains efficiently inhibit the transcriptional activity of ERM. Moreover, mutations of amino acid residues that prevent binding of MED25 to ERM strongly reduce transactivation by ERM. Finally we show that siRNA depletion of MED25 diminishes PEA3-driven expression of MMP-1 and Mediator recruitment. In conclusion, this study identifies the PEA3 group members as the first human transcriptional factors that interact with the MED25 ACID/PTOV domain and establishes MED25 as a crucial transducer of their transactivation potential.
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Affiliation(s)
- Alexis Verger
- IRI USR 3078 CNRS, Parc CNRS de la Haute Borne, 50 avenue de Halley, B.P. 70478, 59658 Villeneuve d'Ascq Cedex, France
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14
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Feldstein O, Ben-Hamo R, Bashari D, Efroni S, Ginsberg D. RBM38 is a direct transcriptional target of E2F1 that limits E2F1-induced proliferation. Mol Cancer Res 2012; 10:1169-77. [PMID: 22798430 DOI: 10.1158/1541-7786.mcr-12-0331] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The E2F family of transcription factors plays a pivotal role in the regulation of cell proliferation in higher eukaryotes and is a critical downstream target of the tumor suppressor pRB. The pRB/E2F pathway is defective in most human tumors, resulting in deregulated E2F activity that induces uncontrolled cell proliferation, a hallmark of tumor cells. The RNA-binding protein RBM38, also named RNPC1, induces cell-cycle arrest in G(1), at least in part, via binding to and stabilizing the mRNA of the cyclin-dependent kinase inhibitor p21. RBM38 levels are altered in human cancer. Generally, RBM38 is overexpressed in various tumors; however, RBM38 mRNA levels are reduced in some breast tumors due to increased methylation of its promoter region. We show here that expression of RBM38 is regulated by E2F1. Specifically, RBM38 mRNA and protein levels are elevated upon activation of either exogenous E2F1 or endogenous E2Fs. Moreover, endogenous E2F1 binds the human RBM38 promoter and E2F1 knockdown reduces RBM38 levels. Our data raise the possibility that E2F1 together with E2F1-regulated RBM38 constitute a negative feedback loop that modulates E2F1 activity. In support of this, inhibition of RBM38 expression increases E2F1-mediated cell-cycle progression. Moreover, in human ovarian cancer, high correlation between expression of E2F1 and RBM38 is associated with increased survival. Overall, our data identify RBM38 as novel transcriptional target of E2F1 that restricts E2F1-induced proliferation. Furthermore, this negative feedback loop seems to restrict tumor aggressiveness, thereby promoting survival of patients with cancer.
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Affiliation(s)
- Orit Feldstein
- The Mina and Everard Goodman Faculty of Life Science, Bar Ilan University, Ramat Gan 52900, Israel.
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15
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Potula HHSK, Morel L. Genetic variation at a Yin-Yang 1 response site regulates the transcription of cyclin-dependent kinase inhibitor p18INK4C transcript in lupus-prone mice. THE JOURNAL OF IMMUNOLOGY 2012; 188:4992-5002. [PMID: 22504641 DOI: 10.4049/jimmunol.1101992] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We have previously shown that a novel -74 C-to-T mutation in the promoter of the cyclin-dependent kinase inhibitor p18(Ink4c) (p18) gene was associated with a reduced p18 expression in B cells from mice carrying the Sle2c1 lupus susceptibility locus. To determine the function of the -74 C/T single nucleotide polymorphism, we have characterized the proximal promoter of the mouse p18 gene. Functional analysis of the 5' flanking region by sequential deletions revealed crucial elements between -300 and +1, confirming the in silico prediction that the -74 T allele created a novel Yin-Yang 1 (YY-1) binding site adjacent to an existing one common to both alleles. Moreover, we found that YY-1, E2F1, and Sp-1 can synergistically enhance the activity of the p18 promoter. Mutational inactivation revealed that YY-1 binding regulates the p18 activity in an allele-dependent fashion. EMSAs with splenic B cell extracts directly demonstrated that YY-1 binds to the p18 promoter with differences between the C and the T alleles. We also determined in vivo by chromatin immunoprecipitation that the T allele resulted in increased YY-1 and decreased Nrf-2 binding to the p18 promoter as compared with the C allele in B cells. Thus, YY-1 is a direct regulator of p18 gene expression in an allele-dependent fashion that is consistent with the lupus-associated T allele, inducing a lower p18 transcriptional activity by increasing YY-1 binding. These results establish the p18 -74 C/T mutation as the leading causal variant for the B1a cell expansion that characterizes the NZB and NZM2410 lupus-prone strains.
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Affiliation(s)
- Hari-Hara S K Potula
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida, Gainesville, FL 32610, USA
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16
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The coactivator activator CoAA regulates PEA3 group member transcriptional activity. Biochem J 2011; 439:469-77. [PMID: 21736557 DOI: 10.1042/bj20110728] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The PEA3 (polyoma enhancer activator 3) group members [ERM (ETS-related molecule), ER81 (ETS-related 81) and PEA3] of the Ets transcription factor family are involved in migration and dissemination processes during organogenesis and cancer development. In the present study, we report that the hnRNP (heterogeneous nuclear ribonucleoprotein)-like protein CoAA (Coactivator activator) interacts with the PEA3 group members and modulates their transcriptional activity. We also demonstrate that the CoAA YQ domain, containing tyrosine/glutamine-rich hexapeptide repeats, is necessary for the interaction, whereas the two N-terminal RRMs (RNA recognition motifs) of CoAA are required to enhance transcriptional activity. Finally, we show that CoAA is involved in the migration-enhancing action of PEA3 on MCF7 human cancer cells, suggesting that CoAA might be an important regulator of PEA3 group member activity during metastasis.
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17
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Gagrica S, Brookes S, Anderton E, Rowe J, Peters G. Contrasting behavior of the p18INK4c and p16INK4a tumor suppressors in both replicative and oncogene-induced senescence. Cancer Res 2011; 72:165-75. [PMID: 22080569 DOI: 10.1158/0008-5472.can-11-2552] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The cyclin-dependent kinase (CDK) inhibitors, p18(INK4c) and p16(INK4a), both have the credentials of tumor suppressors in human cancers and mouse models. For p16(INK4a), the underlying rationale is its role in senescence, but the selective force for inactivation of p18(INK4c) in incipient cancer cells is less clear. Here, we show that in human fibroblasts undergoing replicative or oncogene-induced senescence, there is a marked decline in the levels of p18(INK4c) protein and RNA, which mirrors the accumulation of p16(INK4a). Downregulation of INK4c is not dependent on p16(INK4a), and RAS can promote the loss of INK4c without cell-cycle arrest. Downregulation of p18(INK4c) correlates with reduced expression of menin and E2F1 but is unaffected by acute cell-cycle arrest or inactivation of the retinoblastoma protein (pRb). Collectively, our data question the idea that p18(INK4c) acts as a backup for loss of p16(INK4a) and suggest that the apparent activation of p18(INK4c) in some settings represents delayed senescence rather than increased expression. We propose that the contrasting behavior of the two very similar INK4 proteins could reflect their respective roles in senescence versus differentiation.
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Affiliation(s)
- Sladjana Gagrica
- Molecular Oncology Laboratory, CRUK London Research Institute, London, United Kingdom
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18
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Carcagno AL, Marazita MC, Ogara MF, Ceruti JM, Sonzogni SV, Scassa ME, Giono LE, Cánepa ET. E2F1-mediated upregulation of p19INK4d determines its periodic expression during cell cycle and regulates cellular proliferation. PLoS One 2011; 6:e21938. [PMID: 21765927 PMCID: PMC3135596 DOI: 10.1371/journal.pone.0021938] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2011] [Accepted: 06/10/2011] [Indexed: 11/19/2022] Open
Abstract
Background A central aspect of development and disease is the control of cell proliferation through regulation of the mitotic cycle. Cell cycle progression and directionality requires an appropriate balance of positive and negative regulators whose expression must fluctuate in a coordinated manner. p19INK4d, a member of the INK4 family of CDK inhibitors, has a unique feature that distinguishes it from the remaining INK4 and makes it a likely candidate for contributing to the directionality of the cell cycle. p19INK4d mRNA and protein levels accumulate periodically during the cell cycle under normal conditions, a feature reminiscent of cyclins. Methodology/Principal Findings In this paper, we demonstrate that p19INK4d is transcriptionally regulated by E2F1 through two response elements present in the p19INK4d promoter. Ablation of this regulation reduced p19 levels and restricted its expression during the cell cycle, reflecting the contribution of a transcriptional effect of E2F1 on p19 periodicity. The induction of p19INK4d is delayed during the cell cycle compared to that of cyclin E, temporally separating the induction of these proliferative and antiproliferative target genes. Specific inhibition of the E2F1-p19INK4d pathway using triplex-forming oligonucleotides that block E2F1 binding on p19 promoter, stimulated cell proliferation and increased the fraction of cells in S phase. Conclusions/Significance The results described here support a model of normal cell cycle progression in which, following phosphorylation of pRb, free E2F induces cyclin E, among other target genes. Once cyclinE/CDK2 takes over as the cell cycle driving kinase activity, the induction of p19 mediated by E2F1 leads to inhibition of the CDK4,6-containing complexes, bringing the G1 phase to an end. This regulatory mechanism constitutes a new negative feedback loop that terminates the G1 phase proliferative signal, contributing to the proper coordination of the cell cycle and provides an additional mechanism to limit E2F activity.
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Affiliation(s)
- Abel L. Carcagno
- Laboratorio de Biología Molecular, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
| | - Mariela C. Marazita
- Laboratorio de Biología Molecular, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
| | - María F. Ogara
- Laboratorio de Biología Molecular, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
| | - Julieta M. Ceruti
- Laboratorio de Biología Molecular, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
| | - Silvina V. Sonzogni
- Laboratorio de Biología Molecular, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
| | - María E. Scassa
- Laboratorio de Biología Molecular, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
| | - Luciana E. Giono
- Laboratorio de Biología Molecular, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
| | - Eduardo T. Cánepa
- Laboratorio de Biología Molecular, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
- * E-mail:
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19
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Suzuki DE, Ariza CB, Porcionatto MA, Okamoto OK. Upregulation of E2F1 in cerebellar neuroprogenitor cells and cell cycle arrest during postnatal brain development. In Vitro Cell Dev Biol Anim 2011; 47:492-9. [PMID: 21614651 DOI: 10.1007/s11626-011-9426-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Accepted: 05/11/2011] [Indexed: 12/18/2022]
Abstract
In the developing cerebellum, proliferation of granular neuroprogenitor (GNP) cells lasts until the early postnatal stages when terminal maturation of the cerebellar cortex occurs. GNPs are considered cell targets for neoplastic transformation, and disturbances in cerebellar GNP cell proliferation may contribute to the development of pediatric medulloblastoma. At the molecular level, proliferation of GNPs is regulated through an orchestrated action of the SHH, NOTCH, and WNT pathways, but the underlying mechanisms still need to be dissected. Here, we report that expression of the E2F1 transcription factor in rat GNPs is inversely correlated with cell proliferation rate during postnatal development, as opposed to its traditional SHH-dependent induction of cell cycle. Proliferation of GNPs peaked at postnatal day 3 (P3), with a subsequent continuing decrease in proliferation rates occurring until P12. Such gradual decline in proliferating neuroprogenitors paralleled the extent of cerebellum maturation confirmed by histological analysis with cresyl violet staining and temporal expression profiling of SHH, NOTCH2, and WNT4 genes. A time course analysis of E2F1 expression in GNPs revealed significantly increased levels at P12, correlating with decreased cell proliferation. Expression of the cell cycle inhibitor p18 ( Ink4c ), a target of E2F1, was also significantly higher at P12. Conversely, increased E2F1 expression did not correlate with either SMAC/DIABLO and BCL2 expression profiles or apoptosis of cerebellar cells. Altogether, these results suggest that E2F1 may also be involved in the inhibition of GNP proliferation during rat postnatal development despite its conventional mitogenic effects.
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Affiliation(s)
- Daniela E Suzuki
- Disciplina de Neurologia Experimental, Departamento de Neurologia/Neurocirurgia, Federal University of São Paulo, São Paulo, Brazil
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20
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Xu Z, Potula HHSK, Vallurupalli A, Perry D, Baker H, Croker BP, Dozmorov I, Morel L. Cyclin-dependent kinase inhibitor Cdkn2c regulates B cell homeostasis and function in the NZM2410-derived murine lupus susceptibility locus Sle2c1. THE JOURNAL OF IMMUNOLOGY 2011; 186:6673-82. [PMID: 21543644 DOI: 10.4049/jimmunol.1002544] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Sle2c1 is an NZM2410- and NZB-derived lupus susceptibility locus that induces an expansion of the B1a cell compartment. B1a cells have a repertoire enriched for autoreactivity, and an expansion of this B cell subset occurs in several mouse models of lupus. A combination of genetic mapping and candidate gene analysis presents Cdkn2c, a gene encoding for cyclin-dependent kinase inhibitor p18(INK4c) (p18), as the top candidate gene for inducing the Slec2c1-associated expansion of B1a cells. A novel single nucleotide polymorphism in the NZB allele of the Cdkn2c promoter is associated with a significantly reduced Cdkn2c expression in the splenic B cells and peritoneal cavity B1a cells from Sle2c1-carrying mice, which leads to a defective G1 cell cycle arrest in splenic B cells and increased proliferation of peritoneal cavity B1a cells. As the cell cycle is differentially regulated in B1a and B2 cells, these results suggest that Cdkn2c plays a critical role in B1a cell self-renewal and that its impaired expression leads to an accumulation of these cells with high autoreactive potential.
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Affiliation(s)
- Zhiwei Xu
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida, Gainesville, FL 32610, USA
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21
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Wang X, Meyers C, Guo M, Zheng ZM. Upregulation of p18Ink4c expression by oncogenic HPV E6 via p53-miR-34a pathway. Int J Cancer 2011; 129:1362-72. [PMID: 21128241 DOI: 10.1002/ijc.25800] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2010] [Accepted: 11/04/2010] [Indexed: 01/04/2023]
Abstract
Binding of p53 to miR-34a promoter activates the expression of tumor-suppressive miR-34a. Oncogenic human papillomavirus (HPV) infection downregulates miR-34a expression through viral E6 degradation of p53. In our report, we found that miR-34a specifically targets p18Ink4c, a CDK4 and CDK6 inhibitor induced by E2F transactivation. HPV18(+) HeLa cells with ectopic miR-34a expression or by E6 siRNA knockdown-induced expression of endogenous miR-34a exhibited a substantial reduction of p18Ink4c in a dose-dependent manner, but had no effect on p16Ink4a, another member of CDK4/6 inhibitor family. In contrast, de novo infection by oncogenic HPVs of human keratinocyte-derived raft tissues increased p18Ink4c expression. Suppression of endogenous miR-34a in cell lines with a miR-34a inhibitor also increased p18Ink4c. We found that miR-34a suppresses the expression of p18Ink4c by binding to a specific seed match in the 5' UTR of p18Ink4c. Further investigation found remarkable increase of p18Ink4c in cervical precancer lesions and cervical cancer. Immunohistochemical staining of cervical tissue arrays showed increased expression of p18Ink4c in 68% of cervical cancer, 8.3% of chronic cervical inflammation and 4.8% of normal cervix. Although p18Ink4c inhibits cell proliferation in general and regulates E2F1 expression in HCT116 cells, it appears not to function as a tumor suppressor in cervical cancer cells lacking an intact G1 checkpoint because of viral E7 degradation of pRB. In summary, our study demonstrates an intimate connection among oncogenic HPV E6, p53, miR-34a and p18Ink4c and identifies p18Ink4c as a possible biomarker for cervical cancer.
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Affiliation(s)
- Xiaohong Wang
- Tumor Virus RNA Biology Section, HIV and AIDS Malignancy Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
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22
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Kulkarni MV, Franklin DS. N-Myc is a downstream target of RET signaling and is required for transcriptional regulation of p18(Ink4c) by the transforming mutant RET(C634R). Mol Oncol 2010; 5:24-35. [PMID: 21112821 DOI: 10.1016/j.molonc.2010.10.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Revised: 10/11/2010] [Accepted: 10/12/2010] [Indexed: 12/17/2022] Open
Abstract
Inherited activating mutations in RET predispose humans to Multiple Endocrine Neoplasia type-2 (MEN2). The MEN2A-specific mutation RET(C634R), RET2A, has been shown to simultaneously downregulate the CDKIs p18 and p27, and upregulate cyclin D1. Importantly, the loss of p18 is necessary and sufficient for RET2A-mediated hyperproliferation. The loss of N-Myc in mice results in embryonic lethality due to a lack of neuronal progenitor cells that fail to proliferate, correlate with accumulation of p18 and p27. Therefore, N-Myc may regulate expression of both CDKIs. Also, N-Myc is expressed predominantly in neuroendocrine cells that give rise to the primary cell types affected in MEN2A. Together these studies suggest that N-Myc is a downstream target of RET2A signaling that prevents accumulation of p18 and/or p27. We report that MAPK activation by RET2A leads to a transient induction of N-Myc mRNA and protein levels, and that N-Myc induction is required to maintain low p18 and p27 levels. Induced N-Myc levels correlate with increased binding of N-Myc to an initiator consensus binding site in the p18 promoter, and this binding is essential for RET2A-mediated transcriptional regulation of p18. Finally, loss of N-Myc induction prevents RET2A-mediated hyperproliferation. Our results demonstrate for the first time that N-Myc is a downstream target of RET2A signaling, and propose that induction of N-Myc by RET2A is a key step leading to lower p18 levels during MEN2A tumorigenesis.
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Affiliation(s)
- Mandar V Kulkarni
- Department of Biological Sciences, Purdue University, 915 W. State Street West Lafayette, IN 47907, USA.
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23
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Liu Y, Chu A, Chakroun I, Islam U, Blais A. Cooperation between myogenic regulatory factors and SIX family transcription factors is important for myoblast differentiation. Nucleic Acids Res 2010; 38:6857-71. [PMID: 20601407 PMCID: PMC2978361 DOI: 10.1093/nar/gkq585] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Precise regulation of gene expression is crucial to myogenesis and is thought to require the cooperation of various transcription factors. On the basis of a bioinformatic analysis of gene regulatory sequences, we hypothesized that myogenic regulatory factors (MRFs), key regulators of skeletal myogenesis, cooperate with members of the SIX family of transcription factors, known to play important roles during embryonic skeletal myogenesis. To this day little is known regarding the exact molecular mechanism by which SIX factors regulate muscle development. We have conducted a functional genomic study of the role played by SIX1 and SIX4 during the differentiation of skeletal myoblasts, a model of adult muscle regeneration. We report that SIX factors cooperate with the members of the MRF family to activate gene expression during myogenic differentiation, and that their function is essential to this process. Our findings also support a model where SIX factors function not only ‘upstream’ of the MRFs during embryogenesis, but also ‘in parallel’ to them during myoblast differentiation. We have identified new essential nodes that depend on SIX factor function, in the myogenesis regulatory network, and have uncovered a novel way by which MRF function is modulated during differentiation.
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Affiliation(s)
- Yubing Liu
- Ottawa Institute of Systems Biology and Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Faculty of Medicine, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada
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24
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Wang J, Wang Y, Wong C. Oestrogen-related receptor alpha inverse agonist XCT-790 arrests A549 lung cancer cell population growth by inducing mitochondrial reactive oxygen species production. Cell Prolif 2010; 43:103-13. [PMID: 20447055 PMCID: PMC6495589 DOI: 10.1111/j.1365-2184.2009.00659.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Accepted: 05/15/2009] [Indexed: 01/03/2023] Open
Abstract
OBJECTIVE Although oestrogen-related receptor alpha (ERRalpha) is primarily thought to regulate energy homeostasis, it also serves as a prognostic marker for cancer. The aim of this study was to investigate any connection between ERRalpha activity and cell population growth. MATERIALS AND METHODS XCT-790, an ERRa specific inverse agonist, was employed to suppress ERRa activity in human non-small cell lung cancer cells (NSCLC) A549. Gene expressions were detected using quantitative real-time PCR and Western blot analysis. Mitochondrial mass, membrane potential and reactive oxygen species (ROS) production were measured by staining with Mitotracker green, JC-1 and CM-H(2)DCFDA dyes respectively. Rate of progression through the tricarboxylic acid (TCA) cycle was analysed by measuring activities of citrate synthase and succinate dehydrogenase. Cell cycle analysis was performed by using flow cytometry. RESULTS We found that XCT-790 treatment reduced mitochondrial mass but enhanced mitochondrial ROS production by increasing rate through the TCA cycle, elevating mitochondrial membrane potential (DeltaPsi(m)) and down-regulating expression of superoxide dismutase. It was further demonstrated that XCT-790-induced ROS modulated p53 and Rb signalling pathways and suppressed cell replication. CONCLUSIONS ERRalpha affects cell cycle mechanisms through modulating mitochondrial mass and function. Dysregulation of this essential pathway leads to elevation in mitochondrial ROS production, which in turn modulates activities of tumour suppressors, resulting in cell cycle arrest.
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Affiliation(s)
- J. Wang
- Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Y. Wang
- Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - C. Wong
- Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
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25
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Deniaud E, Baguet J, Chalard R, Blanquier B, Brinza L, Meunier J, Michallet MC, Laugraud A, Ah-Soon C, Wierinckx A, Castellazzi M, Lachuer J, Gautier C, Marvel J, Leverrier Y. Overexpression of transcription factor Sp1 leads to gene expression perturbations and cell cycle inhibition. PLoS One 2009; 4:e7035. [PMID: 19753117 PMCID: PMC2737146 DOI: 10.1371/journal.pone.0007035] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Accepted: 07/13/2009] [Indexed: 11/18/2022] Open
Abstract
Background The ubiquitous transcription factor Sp1 regulates the expression of a vast number of genes involved in many cellular functions ranging from differentiation to proliferation and apoptosis. Sp1 expression levels show a dramatic increase during transformation and this could play a critical role for tumour development or maintenance. Although Sp1 deregulation might be beneficial for tumour cells, its overexpression induces apoptosis of untransformed cells. Here we further characterised the functional and transcriptional responses of untransformed cells following Sp1 overexpression. Methodology and Principal Findings We made use of wild-type and DNA-binding-deficient Sp1 to demonstrate that the induction of apoptosis by Sp1 is dependent on its capacity to bind DNA. Genome-wide expression profiling identified genes involved in cancer, cell death and cell cycle as being enriched among differentially expressed genes following Sp1 overexpression. In silico search to determine the presence of Sp1 binding sites in the promoter region of modulated genes was conducted. Genes that contained Sp1 binding sites in their promoters were enriched among down-regulated genes. The endogenous sp1 gene is one of the most down-regulated suggesting a negative feedback loop induced by overexpressed Sp1. In contrast, genes containing Sp1 binding sites in their promoters were not enriched among up-regulated genes. These results suggest that the transcriptional response involves both direct Sp1-driven transcription and indirect mechanisms. Finally, we show that Sp1 overexpression led to a modified expression of G1/S transition regulatory genes such as the down-regulation of cyclin D2 and the up-regulation of cyclin G2 and cdkn2c/p18 expression. The biological significance of these modifications was confirmed by showing that the cells accumulated in the G1 phase of the cell cycle before the onset of apoptosis. Conclusion This study shows that the binding to DNA of overexpressed Sp1 induces an inhibition of cell cycle progression that precedes apoptosis and a transcriptional response targeting genes containing Sp1 binding sites in their promoter or not suggesting both direct Sp1-driven transcription and indirect mechanisms.
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Affiliation(s)
- Emmanuelle Deniaud
- Inserm, U851, Lyon, France
- Université Lyon1, IFR128, Lyon, France
- Université de Lyon, Lyon, France
| | - Joël Baguet
- Inserm, U851, Lyon, France
- Université Lyon1, IFR128, Lyon, France
- Université de Lyon, Lyon, France
| | - Roxane Chalard
- Inserm, U851, Lyon, France
- Université Lyon1, IFR128, Lyon, France
- Université de Lyon, Lyon, France
| | - Bariza Blanquier
- Université Lyon1, IFR128, Lyon, France
- Université de Lyon, Lyon, France
| | - Lilia Brinza
- Inserm, U851, Lyon, France
- Université Lyon1, IFR128, Lyon, France
- Université de Lyon, Lyon, France
| | - Julien Meunier
- Inserm, U851, Lyon, France
- Université Lyon1, IFR128, Lyon, France
- Université de Lyon, Lyon, France
| | - Marie-Cécile Michallet
- Inserm, U851, Lyon, France
- Université Lyon1, IFR128, Lyon, France
- Université de Lyon, Lyon, France
| | | | | | | | - Marc Castellazzi
- Université Lyon1, IFR128, Lyon, France
- Université de Lyon, Lyon, France
- Inserm, U758, Ecole Normale Supérieure de Lyon, Lyon, France
| | | | | | - Jacqueline Marvel
- Inserm, U851, Lyon, France
- Université Lyon1, IFR128, Lyon, France
- Université de Lyon, Lyon, France
- * E-mail: (JM); (YL)
| | - Yann Leverrier
- Inserm, U851, Lyon, France
- Université Lyon1, IFR128, Lyon, France
- Université de Lyon, Lyon, France
- * E-mail: (JM); (YL)
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Tallack MR, Keys JR, Humbert PO, Perkins AC. EKLF/KLF1 controls cell cycle entry via direct regulation of E2f2. J Biol Chem 2009; 284:20966-74. [PMID: 19457859 DOI: 10.1074/jbc.m109.006346] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Differentiation of erythroid cells requires precise control over the cell cycle to regulate the balance between cell proliferation and differentiation. The zinc finger transcription factor, erythroid Krüppel-like factor (EKLF/KLF1), is essential for proper erythroid cell differentiation and regulates many erythroid genes. Here we show that loss of EKLF leads to aberrant entry into S-phase of the cell cycle during both primitive and definitive erythropoiesis. This cell cycle defect was associated with a significant reduction in the expression levels of E2f2 and E2f4, key factors necessary for the induction of S-phase gene expression and erythropoiesis. We found and validated novel intronic enhancers in both the E2f2 and E2f4 genes, which contain conserved CACC, GATA, and E-BOX elements. The E2f2 enhancer was occupied by EKLF in vivo. Furthermore, we were able to partially restore cell cycle dynamics in EKLF(-/-) fetal liver upon additional genetic depletion of Rb, establishing a genetic causal link between reduced E2f2 and the EKLF cell cycle defect. Finally, we propose direct regulation of the E2f2 enhancer is a generic mechanism by which many KLFs regulate proliferation and differentiation.
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Affiliation(s)
- Michael R Tallack
- Division of Molecular Genetics and Development, Institute for Molecular Bioscience, University of Queensland, Brisbane, 4072, Australia
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27
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Hossain MG, Iwata T, Mizusawa N, Qian ZR, Shima SWN, Okutsu T, Yamada S, Sano T, Yoshimoto K. Expression of p18(INK4C) is down-regulated in human pituitary adenomas. Endocr Pathol 2009; 20:114-21. [PMID: 19401813 DOI: 10.1007/s12022-009-9076-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cyclin-dependent kinase inhibitors represented by the INK4 family comprising p16(INK4A), p15(INK4B), p18(INK4C), and p19(INK4D) are regulators of the cell cycle shown to be aberrant in many types of cancer. Mice lacking p18(Ink4c) exhibit a series of phenotypes including the development of widespread organomegaly and pituitary adenomas. The objective of our study is to examine the role of p18(INK4C) in the pathogenesis of human pituitary tumors. The protein and mRNA levels of p18(INK4C) were examined by immunohistochemistry and real-time reverse transcription-polymerase chain reaction, respectively. The methylation status of the p18(INK4C) gene promoter and somatic mutations of the p18(INK4C) gene were also investigated. p18(INK4C) protein expression was lost or significantly reduced in 64% of pituitary adenomas compared with levels in normal pituitary glands. p18(INK4C) mRNA levels were low in all ACTH adenomas and non-functioning (NF)-FSH and in 42%, 70% and 66% of GH, PRL, and subtype 3 adenomas, respectively. p18(INK4C) mRNA levels were significantly associated with p18(INK4C) protein levels. Neither methylated promoters in pituitary adenomas, except in one NF-FSH adenoma, nor somatic mutations of the p18(INK4C) gene in any pituitary adenomas were detected. The down-regulation of p18(INK4C) expression may contribute to the tumorigenesis of pituitary adenomas.
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Affiliation(s)
- M Golam Hossain
- Department of Medical Pharmacology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan
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28
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Solomon DA, Kim JS, Jean W, Waldman T. Conspirators in a capital crime: co-deletion of p18INK4c and p16INK4a/p14ARF/p15INK4b in glioblastoma multiforme. Cancer Res 2008; 68:8657-60. [PMID: 18974105 PMCID: PMC2828676 DOI: 10.1158/0008-5472.can-08-2084] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Glioblastoma multiforme (GBM) is one of the most dreaded cancer diagnoses due to its poor prognosis and the limited treatment options. Homozygous deletion of the p16(INK4a)/p14(ARF)/p15(INK4b) locus is among the most common genetic alterations in GBM. Two recent studies have shown that deletion and mutation of another INK4 family member, p18(INK4c), also drives the pathogenesis of GBM. This minireview will discuss the known roles for p18(INK4c) in the initiation and progression of cancer and suggest opportunities for future studies.
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Affiliation(s)
- David A. Solomon
- Tumor Biology Training Program, Georgetown University School of Medicine, Washington, District of Columbia, Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University School of Medicine, Washington, District of Columbia
| | - Jung-Sik Kim
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University School of Medicine, Washington, District of Columbia
| | - Walter Jean
- Department of Neurosurgery, Georgetown University School of Medicine, Washington, District of Columbia
| | - Todd Waldman
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University School of Medicine, Washington, District of Columbia
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29
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Racek T, Buhlmann S, Rüst F, Knoll S, Alla V, Pützer BM. Transcriptional repression of the prosurvival endoplasmic reticulum chaperone GRP78/BIP by E2F1. J Biol Chem 2008; 283:34305-14. [PMID: 18840615 DOI: 10.1074/jbc.m803925200] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The endoplasmic reticulum chaperone GRP78/BIP plays a central role in the prosurvival machinery, and its enhanced expression has been implicated in drug resistance, carcinogenesis, and metastasis. E2F1, as part of an antitumor safeguard mechanism, promotes apoptosis regardless of functional p53. Using cells that are defective in p53, we show that E2F1 represses GRP78/BIP at the transcriptional level, and this requires its DNA binding domain. Analysis of human GRP78/BIP promoter reporter constructs revealed that the region between -371 and -109 of the proximal promoter contains major E2F1-responsive elements. Toward understanding the underlying mechanism of this regulation, we performed chromatin immunoprecipitation and gel shift assays, demonstrating that E2F1 directly binds to GC-rich regions in the distal GC-box and endoplasmic reticulum stress response element -126 by interfering with the binding of positive regulatory proteins Sp1 and TFII-I of the ER stress response element-binding factor complex. We further show that TFII-I, which is required for optimal stress induction of GRP78/BIP, is suppressed by E2F1 on the protein level. Finally, our studies suggest a molecular link between the inhibition of GRP78/BIP and E2F1-mediated chemosensitization of tumor cells, underscoring its relevance for cancer treatment. Together, the data provide a new mechanism for the incompletely understood tumor suppressor function of E2F1.
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Affiliation(s)
- Tomás Racek
- Department of Vectorology and Experimental Gene Therapy, Biomedical Research Center, University of Rostock, 18055 Rostock, Germany
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30
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Li L, Zhang G, Zhang Y, Tan J, Huang H, Huang B, Lu J. Sodium butyrate-induced upregulation of p18( INK4C ) gene affects K562 cell G (0)/G (1) arrest and differentiation. Mol Cell Biochem 2008; 319:9-15. [PMID: 18642058 DOI: 10.1007/s11010-008-9870-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Accepted: 07/03/2008] [Indexed: 01/06/2023]
Abstract
Histone deacetylase inhibitor sodium butyrate (NaBu) can induce G(0)/G(1) arrest and erythroid differentiation in K562 cells, but the molecular mechanisms underlying this process are unclear. Here we show that both p18( INK4C ) mRNA and protein levels were upregulated during K562 cell erythroid differentiation induced by NaBu. Moreover, the NaBu activation of p18( INK4C ) was dependent on the integrity of Sp1 clusters in the promoter. NaBu caused hyperacetylation of histones H3 and H4 on endogenous p18( INK4C ) promoter and enhanced binding of transcription factor Sp1 in vivo. Also, overexpression of p18( INK4C ) in K562 cells resulted in G(0)/G(1) arrest and partial erythroid differentiation. Our results suggested that NaBu-mediated p18( INK4C ) regulation played a role in cell cycle arrest and erythroid differentiation in K562 cells.
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Affiliation(s)
- Lin Li
- Institute of Genetics and Cytology, Northeast Normal University, Changchun, China
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31
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Wiedemeyer R, Brennan C, Heffernan TP, Xiao Y, Mahoney J, Protopopov A, Zheng H, Bignell G, Furnari F, Cavenee WK, Hahn WC, Ichimura K, Collins VP, Chu GC, Stratton MR, Ligon KL, Futreal PA, Chin L. Feedback circuit among INK4 tumor suppressors constrains human glioblastoma development. Cancer Cell 2008; 13:355-64. [PMID: 18394558 PMCID: PMC2292238 DOI: 10.1016/j.ccr.2008.02.010] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2007] [Revised: 12/18/2007] [Accepted: 02/12/2008] [Indexed: 11/11/2022]
Abstract
We have developed a nonheuristic genome topography scan (GTS) algorithm to characterize the patterns of genomic alterations in human glioblastoma (GBM), identifying frequent p18(INK4C) and p16(INK4A) codeletion. Functional reconstitution of p18(INK4C) in GBM cells null for both p16(INK4A) and p18(INK4C) resulted in impaired cell-cycle progression and tumorigenic potential. Conversely, RNAi-mediated depletion of p18(INK4C) in p16(INK4A)-deficient primary astrocytes or established GBM cells enhanced tumorigenicity in vitro and in vivo. Furthermore, acute suppression of p16(INK4A) in primary astrocytes induced a concomitant increase in p18(INK4C). Together, these findings uncover a feedback regulatory circuit in the astrocytic lineage and demonstrate a bona fide tumor suppressor role for p18(INK4C) in human GBM wherein it functions cooperatively with other INK4 family members to constrain inappropriate proliferation.
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Affiliation(s)
- Ruprecht Wiedemeyer
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA
| | - Cameron Brennan
- Department of Neurosurgery, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
- Department of Neurosurgery, Weill-Cornell Medical College, New York, NY 10065, USA
- Corresponding author
| | - Timothy P. Heffernan
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA
| | - Yonghong Xiao
- Center for Applied Cancer Science, Belfer Institute for Innovative Cancer Science, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - John Mahoney
- Center for Applied Cancer Science, Belfer Institute for Innovative Cancer Science, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Alexei Protopopov
- Center for Applied Cancer Science, Belfer Institute for Innovative Cancer Science, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Hongwu Zheng
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA
| | - Graham Bignell
- Cancer Genome Project, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Frank Furnari
- Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA 92093, USA
| | - Webster K. Cavenee
- Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA 92093, USA
| | - William C. Hahn
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA
- Center for Cancer Genome Discovery, Dana-Farber Cancer Institute, Boston, MA 02115, USA
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Koichi Ichimura
- Department of Pathology, University of Cambridge, Cambridge CB2 1QP, UK
| | - V. Peter Collins
- Department of Pathology, University of Cambridge, Cambridge CB2 1QP, UK
| | - Gerald C. Chu
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA
- Center for Applied Cancer Science, Belfer Institute for Innovative Cancer Science, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Michael R. Stratton
- Cancer Genome Project, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
- Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK
| | - Keith L. Ligon
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA
- Center for Molecular Oncologic Pathology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
- Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - P. Andrew Futreal
- Cancer Genome Project, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Lynda Chin
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA
- Center for Applied Cancer Science, Belfer Institute for Innovative Cancer Science, Dana-Farber Cancer Institute, Boston, MA 02115, USA
- Department of Dermatology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
- Corresponding author
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32
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Maenz B, Hekerman P, Vela EM, Galceran J, Becker W. Characterization of the human DYRK1A promoter and its regulation by the transcription factor E2F1. BMC Mol Biol 2008; 9:30. [PMID: 18366763 PMCID: PMC2292204 DOI: 10.1186/1471-2199-9-30] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2007] [Accepted: 03/26/2008] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Overexpression of the human DYRK1A gene due to the presence of a third gene copy in trisomy 21 is thought to play a role in the pathogenesis of Down syndrome. The observation of gene dosage effects in transgenic mouse models implies that subtle changes in expression levels can affect the correct function of the DYRK1A gene product. We have therefore characterized the promoter of the human DYRK1A gene in order to study its transcriptional regulation. RESULTS Transcription start sites of the human DYRK1A gene are distributed over 800 bp within a region previously identified as an unmethylated CpG island. We have identified a new alternative noncoding 5'-exon of the DYRK1A gene which is located 772 bp upstream of the previously described transcription start site. Transcription of the two splicing variants is controlled by non-overlapping promoter regions that can independently drive reporter gene expression. We found no evidence of cell- or tissue-specific promoter usage, but the two promoter regions differed in their activity and their regulation. The sequence upstream of exon 1A (promoter region A) induced about 10-fold higher reporter gene activity than the sequence upstream of exon 1B (promoter region B). Overexpression of the transcription factor E2F1 increased DYRK1A mRNA levels in Saos2 and Phoenix cells and enhanced the activity of promoter region B three- to fourfold. CONCLUSION The identification of two alternatively spliced transcripts whose transcription is initiated from differentially regulated promoters regions indicates that the expression of the DYRK1A gene is subject to complex control mechanisms. The regulatory effect of E2F1 suggests that DYRK1A may play a role in cell cycle regulation or apoptosis.
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Affiliation(s)
- Barbara Maenz
- Institute of Pharmacology and Toxicology, Medical Faculty of the RWTH Aachen University, Wendlingweg 2, 52074 Aachen, Germany
| | - Paul Hekerman
- Institute of Pharmacology and Toxicology, Medical Faculty of the RWTH Aachen University, Wendlingweg 2, 52074 Aachen, Germany
| | - Eva M Vela
- Instituto de Neurociencias, CSIC – Universidad Miguel Hernandez, Campus de San Juan, 03550 San Juan (Alicante), Spain
| | - Juan Galceran
- Instituto de Neurociencias, CSIC – Universidad Miguel Hernandez, Campus de San Juan, 03550 San Juan (Alicante), Spain
| | - Walter Becker
- Institute of Pharmacology and Toxicology, Medical Faculty of the RWTH Aachen University, Wendlingweg 2, 52074 Aachen, Germany
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Wierstra I. Sp1: emerging roles--beyond constitutive activation of TATA-less housekeeping genes. Biochem Biophys Res Commun 2008; 372:1-13. [PMID: 18364237 DOI: 10.1016/j.bbrc.2008.03.074] [Citation(s) in RCA: 275] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2008] [Accepted: 03/17/2008] [Indexed: 01/21/2023]
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Gene expression reveals two distinct groups of anal carcinomas with clinical implications. Br J Cancer 2008; 98:1264-73. [PMID: 18349847 PMCID: PMC2359638 DOI: 10.1038/sj.bjc.6604285] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Human papillomavirus (HPV) is a major aetiological agent in anal carcinomas. We here present a study of global gene expression using microarray hybridisation in a collection of anal carcinoma biopsies. Quantitative PCR was used to verify expression of selected genes. All biopsies contained integrated DNA of human papillomavirus subtype 16 (HPV16) and expressed HPV16 E7 mRNA. No other subspecies of HPV were detected in these 13 biopsies as assessed by PCR amplification and DNA sequencing. Unsupervised cluster analysis, based on global mRNA expression, divided the tumour biopsies into two distinct groups. Cluster analysis based on a number of high-risk HPV and/or E2F-regulated genes reproduced this biopsy grouping, suggesting that integrated HPV16 substantially influenced global gene expression in approximately half the biopsies studied. The levels of HPV16 E7 mRNA were significantly different between the two groups, but with considerable overlap. Thus, influence on global gene expression could not be absolutely ascribed to the expression level of HPV16. To investigate whether this distinction in gene expression had prognostic impact, we studied protein expression in an independent cohort of 55 anal carcinomas not included in the microarray study of two differentially expressed candidate genes, minichromosome maintenance complex component 7 (MCM7) and cyclin-dependent kinase inhibitor 2A (CDKN2A or p16). HPV status was assessed by in situ hybridisation. There was a significant association between in situ staining for HPV E7 mRNA and immunostaining for CDKN2A (p16) and MCM7 protein. CDKN2A (p16) mRNA was found significantly differentially expressed between the two tumour groups. However, cluster analysis on genes directly regulated by CDKN2A (p16) could not reproduce this split of biopsies into two groups, suggesting that the transcriptional regulatory activity of CDKN2A in these biopsies is inhibited. Furthermore, protein expression of CDKN2A (p16) could not be associated with survival. MCM7 is directly regulated by E2F and induced by HPV, and its mRNA was found differentially expressed between the two tumour groups. High level of MCM7 protein was found to be associated with both improved relapse-free survival (RFS, P=0.02) and cancer-specific survival (CSS, P=0.03) in anal cancer patients treated with radiation with or without additional chemotherapy.
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Tallack MR, Keys JR, Perkins AC. Erythroid Kruppel-like Factor Regulates the G1 Cyclin Dependent Kinase Inhibitor p18INK4c. J Mol Biol 2007; 369:313-21. [PMID: 17442339 DOI: 10.1016/j.jmb.2007.02.109] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2007] [Revised: 02/25/2007] [Accepted: 02/28/2007] [Indexed: 12/18/2022]
Abstract
Erythroid Kruppel-like factor (EKLF, KLF1) is an essential erythroid cell specific C(2)H(2) zinc finger transcription factor that binds CACC box elements in promoters and distant regulatory elements to activate transcription. Forced expression of EKLF arrests cell division. The cyclin dependent kinase (Cdk) inhibitor p18(INK4c) was identified as a potential novel EKLF target gene from an expression profiling study. The p18(INK4c) protein functions as an inhibitor of Cdk4 and Cdk6 activity during early G1 phase of the cell cycle, thus acting as a physiological brake on cell division. We confirmed p18(INK4c) is downregulated in EKLF null mice by real-time PCR and Western blotting, and identified three closely associated and highly conserved EKLF binding sites (CCNCNCCCN) approximately 1 kb upstream of the p18(INK4c) transcriptional start site. We showed that EKLF binds to one of these elements by gel shift assay and demonstrated this site is capable of driving EKLF dependent transcription. We also determined by chromatin immunoprecipitation (ChIP) that this region of the p18(INK4c) promoter is bound by EKLF in erythroid cells. Thus, EKLF is a direct regulator of p18(INK4c) gene expression, and much of EKLF's role in driving erythroid cell differentiation may occur via p18(INK4c).
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Affiliation(s)
- Michael R Tallack
- Institute for Molecular Bioscience, University of Queensland, St Lucia, Queensland, 4072, Australia
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36
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Lu Z, Luo RZ, Peng H, Rosen DG, Atkinson EN, Warneke C, Huang M, Nishmoto A, Liu J, Liao WSL, Yu Y, Bast RC. Transcriptional and posttranscriptional down-regulation of the imprinted tumor suppressor gene ARHI (DRAS3) in ovarian cancer. Clin Cancer Res 2006; 12:2404-13. [PMID: 16638845 DOI: 10.1158/1078-0432.ccr-05-1036] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE ARHI expression is lost or markedly down-regulated in the majority of ovarian cancers. The mechanism by which ARHI is down-regulated in ovarian cancers is still not clear. Our previous reports indicated that ARHI promoter activity was reduced in ovarian cancer cells, due in part to the effects of negative regulatory transcription factor(s). EXPERIMENTAL DESIGN AND RESULTS We now show that E2F1 and E2F4, but not E2F2, E2F3, or E2F5, bind to the ARHI promoter and repress its activity in ovarian cancer cells. Consistent with this observation, immunochemical staining of cell lines and of 364 samples of ovarian cancer tissue show that the expression of E2F1 and E2F4 proteins is much higher in ovarian cancer cells than in normal ovarian epithelial cells, and that increased expression of E2Fs was negatively correlated with ARHI expression (P < 0.05). Mutation of the putative E2F binding site in the ARHI promoter reversed this inhibitory effect and significantly increased ARHI promoter activity. In addition to the effects of transcriptional regulation, ARHI mRNA also exhibited a significantly reduced half-life in ovarian cancer cells when compared with that in normal ovarian epithelial cells (P < 0.01), suggesting posttranscriptional regulation of ARHI expression. ARHI mRNA contains AU-rich elements (ARE) in the 3'-untranslated region. We have found that these AREs interact with HuR, an ARE-binding protein that stabilizes bound mRNAs, possibly contributing to the rapid turnover of ARHI mRNA. Finally, reduced HuR ARE binding activity was observed in ovarian cancer cells when compared with normal ovarian surface epithelium. CONCLUSIONS Taken together, our data suggest that ARHI expression is regulated at both the transcriptional and the posttranscriptional levels, contributing to the dramatic decrease in ARHI expression in ovarian cancers.
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Affiliation(s)
- Zhen Lu
- Department of Experimental Therapeutics, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, USA
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37
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Dib A, Peterson TR, Raducha-Grace L, Zingone A, Zhan F, Hanamura I, Barlogie B, Shaughnessy J, Kuehl WM. Paradoxical expression of INK4c in proliferative multiple myeloma tumors: bi-allelic deletion vs increased expression. Cell Div 2006; 1:23. [PMID: 17049078 PMCID: PMC1634742 DOI: 10.1186/1747-1028-1-23] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Accepted: 10/18/2006] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND A high proliferative capacity of tumor cells usually is associated with shortened patient survival. Disruption of the RB pathway, which is critically involved in regulating the G1 to S cell cycle transition, is a frequent target of oncogenic events that are thought to contribute to increased proliferation during tumor progression. Previously, we determined that p18INK4c, an essential gene for normal plasma cell differentiation, was bi-allelically deleted in five of sixteen multiple myeloma (MM) cell lines. The present study was undertaken to investigate a possible role of p18INK4c in increased proliferation of myeloma tumors as they progress. RESULTS Thirteen of 40 (33%) human myeloma cell lines do not express normal p18INK4c, with bi-allelic deletion of p18 in twelve, and expression of a mutated p18 fragment in one. Bi-allelic deletion of p18, which appears to be a late progression event, has a prevalence of about 2% in 261 multiple myeloma (MM) tumors, but the prevalence is 6 to 10% in the 50 tumors with a high expression-based proliferation index. Paradoxically, 24 of 40 (60%) MM cell lines, and 30 of 50 (60%) MM tumors with a high proliferation index express an increased level of p18 RNA compared to normal bone marrow plasma cells, whereas this occurs in only five of the 151 (3%) MM tumors with a low proliferation index. Tumor progression is often accompanied by increased p18 expression and an increased proliferation index. Retroviral-mediated expression of exogenous p18 results in marked growth inhibition in three MM cell lines that express little or no endogenous p18, but has no effect in another MM cell line that already expresses a high level of p18. CONCLUSION Paradoxically, although loss of p18 appears to contribute to increased proliferation of nearly 10% of MM tumors, most MM cell lines and proliferative MM tumors have increased expression of p18. Apart from a small fraction of cell lines and tumors that have inactivated the RB1 protein, it is not yet clear how other MM cell lines and tumors have become insensitive to the anti-proliferative effects of increased p18 expression.
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Affiliation(s)
- Amel Dib
- Genetics Branch, Center for Cancer Research, National Cancer Institute, Naval Hospital, Bldg 8, Rm 5101, Bethesda, MD20889-5105, USA
| | - Timothy R Peterson
- Genetics Branch, Center for Cancer Research, National Cancer Institute, Naval Hospital, Bldg 8, Rm 5101, Bethesda, MD20889-5105, USA
- Department of Biology, Masssachusetts Institutes of Technology, Whitehead Institute, 9 Cambridge Center, Rm 359, MA02142, USA
| | - Laura Raducha-Grace
- Genetics Branch, Center for Cancer Research, National Cancer Institute, Naval Hospital, Bldg 8, Rm 5101, Bethesda, MD20889-5105, USA
- University of Pittsburgh School of Medicine, M218 Scaife Hall, Pittsburgh, PA15261, USA
| | - Adriana Zingone
- Genetics Branch, Center for Cancer Research, National Cancer Institute, Naval Hospital, Bldg 8, Rm 5101, Bethesda, MD20889-5105, USA
| | - Fenghuang Zhan
- Myeloma Institute for Research and Therapy, University of Arkansas for Medical Sciences, 4301 Markham St., #816, Little Rock, AR72205-7199, USA
| | - Ichiro Hanamura
- Myeloma Institute for Research and Therapy, University of Arkansas for Medical Sciences, 4301 Markham St., #816, Little Rock, AR72205-7199, USA
- Department of Internal Medicine, Division of Hematology, Aichi Medical University, 21 Karimata, Yazako, Nagakute, Aichi-gun, Aichi 480-1195, Japan
| | - Bart Barlogie
- Myeloma Institute for Research and Therapy, University of Arkansas for Medical Sciences, 4301 Markham St., #816, Little Rock, AR72205-7199, USA
| | - John Shaughnessy
- Myeloma Institute for Research and Therapy, University of Arkansas for Medical Sciences, 4301 Markham St., #816, Little Rock, AR72205-7199, USA
| | - W Michael Kuehl
- Genetics Branch, Center for Cancer Research, National Cancer Institute, Naval Hospital, Bldg 8, Rm 5101, Bethesda, MD20889-5105, USA
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Kherrouche Z, Blais A, Ferreira E, De Launoit Y, Monté D. ASK-1 (apoptosis signal-regulating kinase 1) is a direct E2F target gene. Biochem J 2006; 396:547-56. [PMID: 16512785 PMCID: PMC1482812 DOI: 10.1042/bj20051981] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
In the present study, we show that E2Fs (E2 promoter-binding factors) regulate the expression of ASK-1 (apoptosis signal-regulating kinase 1), which encodes a mitogen-activated protein kinase kinase kinase, also known as MAP3K5. Its mRNA expression is cell-cycle-regulated in human T98G cells released from serum starvation. Moreover, overexpression and RNA interference experiments support the requirement of endogenous E2F/DP (E2F dimerization partner) activity for ASK-1 expression. Characterization of the human ASK-1 promoter demonstrates that the -95/+11 region is critical for E2F-mediated up-regulation. Chromatin immunoprecipitation assays show that E2F1-E2F4 are bound in vivo to the ASK-1 promoter in cycling cells, probably through a non-consensus E2F-binding site located 12 bp upstream of the transcription start site. Mutation of this site completely abolishes the ASK-1 promoter response to E2Fs as well as the E2F1 binding in electrophoretic mobility-shift experiments. Our results indicate that E2Fs modulate the expression of ASK-1 and suggest that some of the cellular functions of ASK-1 may be under the control of E2F transcription factors. Moreover, the up-regulation of ASK-1 may also favour the p53-independent E2F1 apoptotic activity.
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Affiliation(s)
- Zoulika Kherrouche
- *CNRS UMR 8161, Institut de Biologie de Lille, 1 rue Calmette, BP 447, 59021 Lille, France
| | - Alexandre Blais
- †New York University School of Medicine, Department of Pathology, Room MSB 504, 550 First Avenue, New York, NY 10016, U.S.A
| | - Elisabeth Ferreira
- *CNRS UMR 8161, Institut de Biologie de Lille, 1 rue Calmette, BP 447, 59021 Lille, France
| | - Yvan De Launoit
- *CNRS UMR 8161, Institut de Biologie de Lille, 1 rue Calmette, BP 447, 59021 Lille, France
| | - Didier Monté
- *CNRS UMR 8161, Institut de Biologie de Lille, 1 rue Calmette, BP 447, 59021 Lille, France
- To whom correspondence should be addressed (email )
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Lu Z, Luo RZ, Peng H, Huang M, Nishmoto A, Hunt KK, Helin K, Liao WSL, Yu Y. E2F-HDAC complexes negatively regulate the tumor suppressor gene ARHI in breast cancer. Oncogene 2006; 25:230-9. [PMID: 16158053 DOI: 10.1038/sj.onc.1209025] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
ARHI is a maternally imprinted tumor suppressor gene whose expression is markedly downregulated in breast cancer. Reactivation of ARHI expression in breast cancer cells is associated with increased histone H3 acetylation and decreased lysine 9 methylation of histone H3. An ARHI promoter segment that spanned bases -420 to +58 (designated the P2 region) exhibits significantly higher promoter activity in normal cells than in cancer cells. To better understand the molecular mechanisms contributing to this differential transcriptional activity, we sought to identify transcription factors that bind to the P2 region of the ARHI promoter and regulate its activity. Sequence analysis and oligonucleotide competition in electrophoretic mobility shift assays identified an A2 fragment containing an E2F-binding site. Using specific antibodies in supershift assays, we have shown that anti-E2F1 and 4 antibodies can supershift the A2-protein complexes, whereas anti-E2F2 and 6 antibodies cannot, demonstrating that the A2 fragment interacts with specific members of the E2F family proteins. When compared with normal breast epithelial cells, breast cancer cells have significantly elevated expression of E2F1, 4 and increased E2F DNA-binding activity. Moreover, chromatin immunoprecipitation experiments revealed that both E2F1 and 4 bind to the ARHI promoter in breast cancer cells in vivo. This binding was reduced when the cells were treated with the histone deacetylase (HDAC) inhibitor--trichostatin A (TSA). When SKBr3 cells were cotransfected with an ARHI/luciferase reporter and E2F-expression vectors, E2F1 and 4 reduced ARHI promoter activity 2-3-fold, and this reduction could be reversed by TSA treatment. The negative regulation by E2F-HDAC complexes could also be reduced by small interfering RNA of E2F1 and 4. While the retinoblastoma protein, pRB, alone had no effect on ARHI promoter activity, repression by E2F1, but not E2F4, was enhanced by the coexpression of pRB. Taken together, our results suggest that E2F1, 4 and their complexes with HDAC play an important role in downregulating the expression of the tumor suppressor gene ARHI in breast cancer cells.
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Affiliation(s)
- Z Lu
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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40
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Wei Y, Jiang J, Sun M, Chen X, Wang H, Gu J. ATF5 increases cisplatin-induced apoptosis through up-regulation of cyclin D3 transcription in HeLa cells. Biochem Biophys Res Commun 2005; 339:591-6. [PMID: 16300731 DOI: 10.1016/j.bbrc.2005.11.054] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2005] [Accepted: 11/10/2005] [Indexed: 10/25/2022]
Abstract
ATF5 transcription factor plays an essential role in hematopoietic and glioma cell survival and neuronal cell differentiation. Here, we report for the first time the pro-apoptosis role of ATF5 and identify Cyclin D3 as an ATF5-targeted apoptosis-related gene. The ectopic expression of ATF5 in HeLa cells could markedly increase cisplatin-induced apoptosis and the cleavage of Caspase-3, and induce Cyclin D3 mRNA expression via cooperation with E2F1 transcription factor. Moreover, the interference of Cyclin D3 expression by transfection with Cyclin D3 RNAi could protect cells from ATF5-mediated apoptosis induced by cisplatin, indicating the contribution of Cyclin D3 in ATF5-mediated apoptosis. Taken together, these results suggest that ATF5 increases cisplatin-induced apoptosis through up-regulation of Cyclin D3 transcription, which elicits survival signals in HeLa cells.
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Affiliation(s)
- Yuanyan Wei
- State Key Laboratory of Genetic Engineering and Gene Research Center, Shanghai Medical College of Fudan University, Shanghai 200032, People's Republic of China
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41
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Karnik SK, Hughes CM, Gu X, Rozenblatt-Rosen O, McLean GW, Xiong Y, Meyerson M, Kim SK. Menin regulates pancreatic islet growth by promoting histone methylation and expression of genes encoding p27Kip1 and p18INK4c. Proc Natl Acad Sci U S A 2005; 102:14659-64. [PMID: 16195383 PMCID: PMC1253549 DOI: 10.1073/pnas.0503484102] [Citation(s) in RCA: 286] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Menin, the product of the Men1 gene mutated in familial multiple endocrine neoplasia type 1 (MEN1), regulates transcription in differentiated cells. Menin associates with and modulates the histone methyltransferase activity of a nuclear protein complex to activate gene expression. However, menin-dependent histone methyltransferase activity in endocrine cells has not been demonstrated, and the mechanism of endocrine tumor suppression by menin remains unclear. Here, we show that menin-dependent histone methylation maintains the in vivo expression of cyclin-dependent kinase (CDK) inhibitors to prevent pancreatic islet tumors. In vivo expression of CDK inhibitors, including p27 and p18, and other cell cycle regulators is disrupted in mouse islet tumors lacking menin. Chromatin immunoprecipitation studies reveal that menin directly associates with regions of the p27 and p18 promoters and increases methylation of lysine 4 (Lys-4) in histone H3 associated with these promoters. Moreover, H3 Lys-4 methylation associated with p27 and p18 is reduced in islet tumors from Men1 mutant mice. Thus, H3 Lys-4 methylation is a crucial function of menin in islet tumor suppression. These studies suggest an epigenetic mechanism of tumor suppression: by promoting histone modifications, menin maintains transcription at multiple loci encoding cell cycle regulators essential for endocrine growth control.
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Affiliation(s)
- Satyajit K Karnik
- Departments of Developmental Biology and Medicine (Oncology Division), Stanford University School of Medicine, Stanford, CA 94305-5329
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Gizard F, Robillard R, Barbier O, Quatannens B, Faucompré A, Révillion F, Peyrat JP, Staels B, Hum DW. TReP-132 controls cell proliferation by regulating the expression of the cyclin-dependent kinase inhibitors p21WAF1/Cip1 and p27Kip1. Mol Cell Biol 2005; 25:4335-48. [PMID: 15899840 PMCID: PMC1140623 DOI: 10.1128/mcb.25.11.4335-4348.2005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The transcriptional regulating protein of 132 kDa (TReP-132) has been identified in steroidogenic tissues, where it acts as a coactivator of steroidogenic factor 1 (SF-1). We show here that TReP-132 plays a role in the control of cell proliferation. In human HeLa cells, TReP-132 knockdown by using small interfering RNA resulted in increased G(1)-->S cell cycle progression. The growth-inhibitory effects of TReP-132 was further shown to be mediated by induction of G(1) cyclin-dependent kinase inhibitors p21(WAF1) (p21) and p27(KIP1) (p27) expression levels. As a consequence, G(1) cyclin/cyclin-dependent kinase activities and pRB phosphorylation were markedly reduced, and cell cycle progression was blocked in the G(1) phase. The stimulatory effect of TReP-132 on p21 and p27 gene transcription involved interaction of TReP-132 with the transcription factor Sp1 at proximal Sp1-binding sites in their promoters. Moreover, in different breast tumor cell lines, endogenous TReP-132 expression was positively related with a lower proliferation rate. In addition, TReP-132 knockdown resulted in enhanced cell proliferation and lowered p21 and p27 mRNA levels in the steroid-responsive and nonresponsive T-47D and MDA-MB-231 cell lines, respectively. Finally, a statistic profiling of human breast tumor samples highlighted that expression of TReP-132 is correlated with p21 and p27 levels and is associated with lower tumor incidence and aggressiveness. Together, these results identify TReP-132 as a basal cell cycle regulatory protein acting, at least in part, by interacting with Sp1 to activate the p21 and p27 gene promoters.
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Affiliation(s)
- Florence Gizard
- Centre de Recherche en Endocrinologie Moléculaire et Oncologique, Université Laval, Québec G1V 4G2, Canada
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Berteaux N, Lottin S, Monté D, Pinte S, Quatannens B, Coll J, Hondermarck H, Curgy JJ, Dugimont T, Adriaenssens E. H19 mRNA-like noncoding RNA promotes breast cancer cell proliferation through positive control by E2F1. J Biol Chem 2005; 280:29625-36. [PMID: 15985428 DOI: 10.1074/jbc.m504033200] [Citation(s) in RCA: 283] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The imprinted H19 gene has riboregulatory functions. We show here that H19 transcription is up-regulated during the S-phase of growth-stimulated cells and that the H19 promoter is activated by E2F1 in breast cancer cells. H19 repression by pRb and E2F6 confirms the E2F1-dependent control of the H19 promoter. Consistently, we demonstrate by chromatin immunoprecipitation assays that endogenous E2F1 is recruited to the H19 promoter in vivo. The functionality of E2F promoter sites was further confirmed by gel shift and mutagenesis experiments, revealing that these sites are required for binding and promoter response to E2F1 exogenous expression and serum stimulation. Furthermore, we show that H19 overexpression confers a growth advantage on breast cancer cells released from growth arrest as well as in asynchronously growing cells. The H19 knockdown by small interfering RNA duplexes impedes S-phase entry in both wild-type and stably H19-transfected cells. Based on these findings, we conclude that the H19 RNA is actively linked to E2F1 to promote cell cycle progression of breast cancer cells. This clearly supports the H19 oncogenic function in breast tumor genesis.
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Affiliation(s)
- Nathalie Berteaux
- ERI-8 INSERM Signalisation des Facteurs de Croissance dans le Cancer du Sein, Protéomique Fonctionnelle, UPRES-EA 1033, IFR 118, Université des Sciences et Technologies de Lille (USTL), Villeneuve d'Ascq, France
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Kherrouche Z, De Launoit Y, Monte D. The NRF-1/alpha-PAL transcription factor regulates human E2F6 promoter activity. Biochem J 2005; 383:529-36. [PMID: 15257658 PMCID: PMC1133746 DOI: 10.1042/bj20040935] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
E2F6 is widely expressed in human tissues and cell lines. Recent studies have demonstrated its involvement in developmental patterning and in the regulation of various genes implicated in chromatin remodelling. Despite a growing number of studies, nothing is really known concerning the E2F6 expression regulation. To understand how cells control E2F6 expression, we analysed the activity of the previously cloned promoter region of the human E2F6 gene. DNase I footprinting, gel electrophoreticmobility shift, transient transfection and site-directed mutagenesis experiments allowed the identification of two functional NRF-1/alpha-PAL (nuclear respiratory factor-1/alpha-palindrome-binding protein)-binding sites within the human E2F6 core promoter region, which are conserved in the mouse and rat E2F6 promoter region. Moreover, ChIP (chromatin immunoprecipitation) analysis demonstrated that overexpressed NRF-1/alpha-PAL is associated in vivo with the E2F6 promoter. Furthermore, overexpression of full-length NRF-1/alpha-PAL enhanced E2F6 promoter activity, whereas expression of its dominant-negative form reduced the promoter activity. Our results indicate that NRF-1/alpha-PAL is implicated in the regulation of basal E2F6 gene expression.
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Affiliation(s)
- Zoulika Kherrouche
- *CNRS UMR 8117, Institut de Biologie de Lille, 1 rue Calmette, BP 447, 59021 Lille, France
| | - Yvan De Launoit
- *CNRS UMR 8117, Institut de Biologie de Lille, 1 rue Calmette, BP 447, 59021 Lille, France
- †Laboratoire de Virologie Moléculaire, Faculté de Médecine, Université Libre de Bruxelles, CP 614, 808 route de Lennik, 1070 Brussels, Belgium
| | - Didier Monte
- *CNRS UMR 8117, Institut de Biologie de Lille, 1 rue Calmette, BP 447, 59021 Lille, France
- To whom correspondence should be addressed (email )
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45
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Pei XH, Xiong Y. Biochemical and cellular mechanisms of mammalian CDK inhibitors: a few unresolved issues. Oncogene 2005; 24:2787-95. [PMID: 15838515 DOI: 10.1038/sj.onc.1208611] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
p21 and p16, first identified as two small molecular weight proteins in CDK and cyclin immunocomplexes, represent two distinct families constituting a total of seven CDK inhibitors in mammalian cells. The physiological functions of these genes are believed to be broadly involved in connecting various cellular pathways to cell cycle control. Extensive studies over the past 10 years have led to a fairly clear understanding of their biochemical and cellular mechanisms and have also left some unresolved and controversial issues.
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Affiliation(s)
- Xin-Hai Pei
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7295, USA
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46
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Seelan RS, Parthasarathy LK, Parthasarathy RN. E2F1 regulation of the human myo-inositol 1-phosphate synthase (ISYNA1) gene promoter. Arch Biochem Biophys 2004; 431:95-106. [PMID: 15464731 DOI: 10.1016/j.abb.2004.08.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2004] [Indexed: 01/23/2023]
Abstract
Human myo-inositol 1-phosphate synthase (IP synthase; E.C. 5.5.1.4), encoded by ISYNA1, catalyzes the de novo synthesis of inositol 1-phosphate from glucose 6-phosphate. It is a potential target for mood-stabilizing drugs such as lithium and valproate. But, very little is known about the regulation of human IP synthase. Here, we have characterized the minimal promoter of ISYNA1 and show that it is upregulated by E2F1. Upregulation occurs in a dose-dependent fashion and can be suppressed by ectopic expression of Rb. EMSA and antibody supershift analysis identified a functional E2F binding motif at -117. Complex formation at this site was competed by an excess of unlabeled Sp1 oligo consistent with the -117 E2F site overlapping an Sp1 motif. Because the -117 E2F motif is not a high-affinity binding site, we propose that the upregulation of ISYNA1 occurs through the cooperative interaction of several low-affinity E2F binding motifs present in the minimal promoter.
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Affiliation(s)
- Ratnam S Seelan
- Molecular Neuroscience and Bioinformatics Laboratories, Mental Health, Behavioral Science and Research Services, VA Medical Center (151), Louisville, KY 40206, USA
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47
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Hlaing M, Spitz P, Padmanabhan K, Cabezas B, Barker CS, Bernstein HS. E2F-1 Regulates the Expression of a Subset of Target Genes during Skeletal Myoblast Hypertrophy. J Biol Chem 2004; 279:43625-33. [PMID: 15304485 DOI: 10.1074/jbc.m408391200] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cellular hypertrophy, or growth without division, is an adaptive response to various physiological and pathological stimuli in postmitotic muscle. We demonstrated previously that angiotensin II stimulates hypertrophy in C2C12 myoblasts by transient activation of the cyclin-dependent kinase 4 complex, subsequent phosphorylation of retinoblastoma protein, release of histone deacetylase 1 from the retinoblastoma protein inhibitory complex, and partial activation of the transcription factor E2F-1. These observations led us to propose a model in which partial inactivation of the retinoblastoma protein complex leads to the derepression of a subset of E2F-1 targets necessary for cell growth without division during hypertrophy. We now present data that support this model and suggest the mechanism by which E2F-1 regulates hypertrophy. We examined expression profiles of angiotensin II-stimulated myoblasts and identified a subset of E2F-1 target genes that are specifically regulated during the hypertrophic response. We showed that the expression of E2F-1 targets involved in G1/S transit, DNA replication, and mitosis is not altered during the hypertrophic response, while the expression of E2F-1-regulated genes controlling early G1 progression, cytoskeletal organization, protein synthesis, mitochondrial function, and programmed cell death is up-regulated. Furthermore, we demonstrated that activation of cytochrome c oxidase genes occurs during the development of hypertrophy and that cytochrome c oxidase IV is a direct transcriptional target of E2F-1. These studies demonstrated that E2F-1 activity at specific promoters is dependent on physiological circumstances and that E2F-1 should be considered a potential target in the treatment of pathologic hypertrophy.
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Affiliation(s)
- Myint Hlaing
- Cardiovascular Research Institute, University of California, San Francisco 94143, USA
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48
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Tang S, Bhatia B, Zhou J, Maldonado CJ, Chandra D, Kim E, Fischer SM, Butler AP, Friedman SL, Tang DG. Evidence that Sp1 positively and Sp3 negatively regulate and androgen does not directly regulate functional tumor suppressor 15-lipoxygenase 2 (15-LOX2) gene expression in normal human prostate epithelial cells. Oncogene 2004; 23:6942-53. [PMID: 15247906 DOI: 10.1038/sj.onc.1207913] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In this project, we studied the gene regulation of 15-lipoxygenase 2 (15-LOX2), the most abundant arachidonate-metabolizing LOX in adult human prostate and a negative cell-cycle regulator in normal human prostate (NHP) epithelial cells. Through detailed in silico promoter examination and promoter deletion and activity analysis, we found that several Sp1 sites (i.e., three GC boxes and one CACCC box) in the proximal promoter region play a critical role in regulating 15-LOX2 expression in NHP cells. Several pieces of evidence further suggest that the Sp1 and Sp3 proteins play a physiologically important role in positively and negatively regulating the 15-LOX2 gene expression, respectively. First, mutations in the GC boxes affected the 15-LOX2 promoter activity. Second, both Sp1 and Sp3 proteins were detected in the protein complexes that bound the GC boxes revealed by electrophoretic mobility shift assay. Third, importantly, inhibition of Sp1 activity or overexpression of Sp3 both inhibited the endogenous 15-LOX2 mRNA expression. Since 15-LOX2 is normally expressed in the prostate luminal epithelial cells, we subsequently explored whether androgen/androgen receptor may directly regulate its gene expression. The results indicate that androgen does not directly regulate 15-LOX2 gene expression. Together, these observations provide insight on how 15-LOX2 gene expression may be regulated in NHP cells.
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Affiliation(s)
- Shaohua Tang
- Department of Carcinogenesis, Science Park-Research Division, The University of Texas MD Anderson Cancer Center, 1808 Park Rd. 1C, Smithville, TX 78957, USA
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49
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Sánchez-Aguilera A, Delgado J, Camacho FI, Sánchez-Beato M, Sánchez L, Montalbán C, Fresno MF, Martín C, Piris MA, García JF. Silencing of the p18INK4c gene by promoter hypermethylation in Reed-Sternberg cells in Hodgkin lymphomas. Blood 2004; 103:2351-7. [PMID: 14645011 DOI: 10.1182/blood-2003-07-2356] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
p18INK4c is a cyclin-dependent kinase (CDK) inhibitor that interferes with the Rb-kinase activity of CDK6/CDK4. Disruption of p18INK4c in mice impairs B-cell terminal differentiation and confers increased susceptibility to tumor development; however, alterations of p18INK4c in human tumors have rarely been described. We used a tissue-microarray approach to analyze p18INK4c expression in 316 Hodgkin lymphomas (HLs). Nearly half of the HL cases showed absence of p18INK4c protein expression by Reed-Sternberg (RS) cells, in contrast with the regular expression of p18INK4c in normal germinal center cells. To investigate the cause of p18INK4c repression in RS cells, the methylation status of the p18INK4c promoter was analyzed by methylation-specific polymerase chain reaction (PCR) and bisulfite sequencing. Hypermethylation of the p18INK4c promoter was detected in 2 of 4 HL-derived cell lines, but in none of 7 non-Hodgkin lymphoma (NHL)–derived cell lines. We also detected p18INK4c hypermethylation, associated with absence of protein expression, in 5 of 26 HL tumors. The correlation of p18INK4c immunostaining with the follow-up of the patients showed shorter overall survival in negative cases, independent of the International Prognostic Score. These findings suggest that p18INK4c may function as a tumor suppressor gene in HL, and its inactivation may contribute to the cell cycle deregulation and defective terminal differentiation characteristic of the RS cells.
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Affiliation(s)
- Abel Sánchez-Aguilera
- Lymphoma Group, Molecular Pathology Program, and the Immunohistochemistry and Histology Unit, Centro Nacional de Investigaciones Oncológicas, E-28029 Madrid, Spain
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50
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Mousli M, Hopfner R, Abbady AQ, Monté D, Jeanblanc M, Oudet P, Louis B, Bronner C. ICBP90 belongs to a new family of proteins with an expression that is deregulated in cancer cells. Br J Cancer 2003; 89:120-7. [PMID: 12838312 PMCID: PMC2394215 DOI: 10.1038/sj.bjc.6601068] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
ICBP90 (Inverted CCAAT box Binding Protein of 90 kDa) is a recently identified nuclear protein that binds to one of the inverted CCAAT boxes of the topoisomerase IIalpha (TopoIIalpha) gene promoter. Here, we show that ICBP90 shares structural homology with several other proteins, including Np95, the human and mouse NIRF, suggesting the emergence of a new family of nuclear proteins. Towards elucidating the functions of this family, we analysed the expression of ICBP90 in various cancer or noncancer cell lines and in normal or breast carcinoma tissues. We found that cancer cell lines express higher levels of ICBP90 and TopoIIalpha than noncancer cell lines. By using cell-cycle phase-blocking drugs, we show that in primary cultured human lung fibroblasts, ICBP90 expression peaks at late G1 and during G2/M phases. In contrast, cancer cell lines such as HeLa, Jurkat and A549 show constant ICBP90 expression throughout the entire cell cycle. The effect of overexpression of E2F-1 is more efficient on ICBP90 and TopoIIalpha expression in noncancer cells (IMR90, WI38) than in cancer cells (U2OS, SaOs). Together, these results show that ICBP90 expression is altered in cancer cell lines and is upregulated by E2F-1 overexpression with an efficiency depending on the cancer status of the cell line.
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Affiliation(s)
- M Mousli
- Inserm U392, Faculté de Pharmacie, 74 route du Rhin, B.P. 60024, 67401 Illkirch Cedex, France
| | - R Hopfner
- Inserm U392, Faculté de Pharmacie, 74 route du Rhin, B.P. 60024, 67401 Illkirch Cedex, France
- IGBMC, CNRS UMR 7104, Inserm U184, B.P. 163, 67404 Illkirch, Cedex, France
| | - A-Q Abbady
- Inserm U392, Faculté de Pharmacie, 74 route du Rhin, B.P. 60024, 67401 Illkirch Cedex, France
| | - D Monté
- Institut de Biologie de Lille, UMR 8117 CNRS/Institut Pasteur de Lille, 1 rue Calmette, 59021 Lille Cedex, France
| | - M Jeanblanc
- Inserm U392, Faculté de Pharmacie, 74 route du Rhin, B.P. 60024, 67401 Illkirch Cedex, France
| | - P Oudet
- IGBMC, CNRS UMR 7104, Inserm U184, B.P. 163, 67404 Illkirch, Cedex, France
| | - B Louis
- Centre de Pathologie, 18 rue Kempf, 67000 Strasbourg, France
| | - C Bronner
- Inserm U392, Faculté de Pharmacie, 74 route du Rhin, B.P. 60024, 67401 Illkirch Cedex, France
- Inserm U392, Faculté de Pharmacie, 74 route du Rhin, B.P. 60024, 67401 Illkirch Cedex, France. E-mail:
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