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Sayadi M, Rostami S, Nadali F, Fathabad ME, Riazi-Rad F, Sayadi K, Ajdary S. miR-192 overexpression effect on DHFR and TYMS in acute lymphoblastic leukemia. GENE REPORTS 2020. [DOI: 10.1016/j.genrep.2020.100887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Chang WN, Chi WY, Kao TT, Tsai JN, Liu W, Liang SS, Chiu CC, Chen BH, Fu TF. The Transgenic Zebrafish Display Fluorescence Reflecting the Expressional Dynamics of Dihydrofolate Reductase. Zebrafish 2017; 14:223-235. [DOI: 10.1089/zeb.2016.1381] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Wen-Ni Chang
- The Institute of Basic Medical Science, National Cheng Kung University, Tainan, Taiwan
| | - Wan-Yu Chi
- The Institute of Basic Medical Science, National Cheng Kung University, Tainan, Taiwan
| | - Tseng-Ting Kao
- The Institute of Basic Medical Science, National Cheng Kung University, Tainan, Taiwan
| | - Jen-Ning Tsai
- Department of Medical Laboratory and Biotechnology, Chung Shan Medical University, Taichung, Taiwan
- Department of Clinical Laboratory, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - Wangta Liu
- Department of Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Shih-Shin Liang
- Department of Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan
- The Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Chien-Chih Chiu
- Department of Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Bing-Hung Chen
- Department of Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan
- The Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
- Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - Tzu-Fun Fu
- The Institute of Basic Medical Science, National Cheng Kung University, Tainan, Taiwan
- The Department of Medical Laboratory Science and Biotechnology, National Cheng Kung University, Tainan, Taiwan
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Oleaga C, Ciudad CJ, Izquierdo-Pulido M, Noé V. Cocoa flavanol metabolites activate HNF-3β, Sp1, and NFY-mediated transcription of apolipoprotein AI in human cells. Mol Nutr Food Res 2013; 57:986-95. [PMID: 23293065 DOI: 10.1002/mnfr.201200507] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 10/23/2012] [Accepted: 11/04/2012] [Indexed: 12/28/2022]
Abstract
SCOPE To identify the mechanisms by which cocoa induces HDL levels and since apolipoprotein AI (ApoAI) is the major protein in HDLs, we analyzed, upon incubation with cocoa metabolites, ApoAI mRNA levels, its transcriptional regulation, and the levels of the transcription factors involved in this process. METHODS AND RESULTS Epicatechin and cocoa metabolites caused an increase in ApoAI expression in HepG2 cells. Electrophoretic mobility shift assays revealed the involvement of Sites A and B of the ApoAI promoter in the induction of ApoAI mRNA upon incubation with cocoa metabolites. Using supershift assays, we demonstrated the binding of HNF-3β, HNF-4, ER-α, and RXR-α to Site A and the binding of HNF-3β, NFY, and Sp1 to Site B. Luciferase assays performed with a construct containing Site B confirmed its role in the upregulation of ApoAI by cocoa metabolites. Incubation with 3-methyl-epicatechin led to an increase in HNF-3β mRNA, HNF-3β, ER-α, Sp1, and NFY protein levels and the activation of ApoAI transcription mediated by NFY, Sp1, and ER-α. CONCLUSION The activation of ApoAI transcription through Site B by cocoa flavanol metabolites is mainly mediated by an increase in HNF-3β, with a significant contribution of Sp1 and NFY, as a mechanism for the protective role of these compounds in cardiovascular diseases.
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Affiliation(s)
- Carlota Oleaga
- Department of Biochemistry and Molecular Biology, School of Pharmacy, University of Barcelona, Barcelona, Spain
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Sugimoto H, Banchio C, Vance DE. Transcriptional regulation of phosphatidylcholine biosynthesis. Prog Lipid Res 2008; 47:204-20. [PMID: 18295604 DOI: 10.1016/j.plipres.2008.01.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Phosphatidylcholine biosynthesis in animal cells is primarily regulated by the rapid translocation of CTP:phosphocholine cytidylyltransferase alpha between a soluble form that is inactive and a membrane-associated form that is activated. Until less than 10 years ago there was no information on the transcriptional regulation of phosphatidylcholine biosynthesis. Research has identified the transcription factors Sp1, Rb, TEF4, Ets-1 and E2F as enhancing the expression of the cytidylyltransferase and Net as a factor that represses cytidylyltransferase expression. Key transcription factors involved in cholesterol or fatty acid metabolism (SREBPs, LXRs, PPARs) do not have a major role in transcriptional regulation of the cytidylyltransferase. Rather than being linked to cholesterol or energy metabolism, regulation of the cytidylyltransferase is linked to the cell cycle, cell growth and differentiation. Transcriptional regulation of phospholipid biosynthesis is more elegantly understood in yeast and involves responses to inositol, choline and zinc in the culture medium.
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Affiliation(s)
- Hiroyuki Sugimoto
- Department of Biochemistry, Dokkyo Medical University School of Medicine, Mibu 321-0293, Japan.
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Zhang J, Jia Z, Li Q, Wang L, Rashid A, Zhu Z, Evans DB, Vauthey JN, Xie K, Yao JC. Elevated expression of vascular endothelial growth factor correlates with increased angiogenesis and decreased progression-free survival among patients with low-grade neuroendocrine tumors. Cancer 2007; 109:1478-86. [PMID: 17340592 DOI: 10.1002/cncr.22554] [Citation(s) in RCA: 159] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND Vascular endothelial growth factor (VEGF) is a critical proangiogenic factor in solid tumors. However, its expression and role in human neuroendocrine tumor development and progression remains unclear. METHODS Using immunohistochemistry, VEGF and Sp1 expression patterns were investigated in 50 cases of human gastrointestinal neuroendocrine tumor having various clinicopathologic characteristics. RESULTS It was found that strong VEGF expression was detected in tumor cells, whereas no or very weak VEGF expression was detected in stromal cells surrounding or within the tumors. The levels of VEGF expression directly correlated with the expression levels of Sp1 and microvessel density. Strong, weak, and negative VEGF expression was observed in 32%, 54%, and 14% of cases, respectively. Compared with the group with negative VEGF expression, VEGF (weak/strong) expression was associated with metastasis (14% versus 58%; P = .03). The median progression-free survival (PFS) durations of patients with strong and weak VEGF expression were 29 months and 81 months, respectively. With a median follow-up duration of 50 months, the median PFS duration for the group with negative VEGF expression has not been reached. Compared with the log-rank test, VEGF expression was associated with poor PFS (P = .02). Using in vitro and in vivo models, human carcinoid cell lines were treated with bevacizumab, a monoclonal antibody targeting VEGF. Bevacizumab did not inhibit the growth of carcinoid cells in vitro but significantly reduced tumor angiogenesis and impaired tumor growth in animals. CONCLUSIONS The data suggest that overexpression of VEGF promotes the growth of human neuroendocrine tumors in part through up-regulation of angiogenesis.
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MESH Headings
- Angiogenesis Inhibitors/pharmacology
- Animals
- Antibodies, Monoclonal/pharmacology
- Antibodies, Monoclonal, Humanized
- Bevacizumab
- Biomarkers, Tumor/analysis
- Blotting, Western
- Carcinoma, Neuroendocrine/blood supply
- Carcinoma, Neuroendocrine/metabolism
- Carcinoma, Neuroendocrine/mortality
- Cell Line, Tumor
- Cell Proliferation/drug effects
- Disease-Free Survival
- Female
- Humans
- Immunohistochemistry
- Mice
- Mice, Nude
- Neovascularization, Pathologic/metabolism
- Prognosis
- Vascular Endothelial Growth Factor A/biosynthesis
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Affiliation(s)
- Jun Zhang
- Department of Gastrointestinal Medical Oncology, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA
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Banchio C, Lingrell S, Vance DE. Role of Histone Deacetylase in the Expression of CTP:Phosphocholine Cytidylyltransferase α. J Biol Chem 2006; 281:10010-5. [PMID: 16484221 DOI: 10.1074/jbc.m513503200] [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: 11/06/2022] Open
Abstract
Histone acetylation plays an important role in chromatin remodeling and gene expression. The molecular mechanisms involved in cell-specific expression of CTP:phosphocholine cytidylyltransferase alpha (CTalpha) are not fully understood. In this study, we investigated whether or not histone deacetylation is involved in repression of CTalpha expression in quiescent C3H10T1/2 mouse embryo fibroblasts. We have examined the contributions of the Sp1 and E2F binding sites in the repression of CTalpha gene expression. Immunoprecipitation experiments showed that histone deacetylase 1 (HDAC1) and HDAC activity are associated with Sp1 in serum-starved cells or during serum stimulation. However, HDAC1 association with E2F was only detected in serum-starved cells. By chromatin immunoprecipitation assays, we detected both direct and indirect association of HDAC1 with the CTalpha promoter. Treatment with the HDAC inhibitor trichostatin A induced CTalpha expression. Our data suggest that HDAC1 plays a critical role in CTalpha repression and that Sp1 and E2F may serve as key targets for HDAC1-mediated CTalpha repression in fibroblasts.
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Affiliation(s)
- Claudia Banchio
- Department of Biochemistry and Canadian Institutes of Health Research Group in Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta T6G 2S2, Canada.
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7
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Peñuelas S, Alemany C, Noé V, Ciudad CJ. The expression of retinoblastoma and Sp1 is increased by low concentrations of cyclin-dependent kinase inhibitors. ACTA ACUST UNITED AC 2003; 270:4809-22. [PMID: 14653808 DOI: 10.1046/j.1432-1033.2003.03874.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We examined the effect of suboptimal concentrations of cyclin-dependent kinase inhibitors, which do not interfere with cell proliferation, on retinoblastoma expression in hamster (Chinese hamster ovary K1) and human (K562 and HeLa) cells. To achieve this, we used the chemical inhibitors roscovitine and olomoucine (which inhibit CDK2 preferentially), UCN-01 (which also inhibits CDK4/6) and p21 (as an intrinsic inhibitor). All chemical inhibitors and overexpression of p21 strongly induced retinoblastoma protein expression. UCN-01-mediated retinoblastoma expression was caused by an increase in both the levels of retinoblastoma mRNA and the stability of the protein. The expression of the transcription factor Sp1, a retinoblastoma-interacting protein, was also enhanced by all the cyclin-dependent kinase inhibitors tested. However, Sp1 expression was caused by an increase in the levels of Sp1 mRNA without modification in the stability of the protein. By using luciferase experiments, the transcriptional activation of both retinoblastoma and Sp1 promoters by UCN-01 was confirmed. Bisindolylmaleimide I, at concentrations causing a similar or higher inhibition of protein kinase C than UCN-01, provoked a lower activation of retinoblastoma and Sp1 expression. Finally, the effects of cyclin-dependent kinase inhibitors on dihydrofolate reductase gene expression were evaluated. Treatment with UCN-01 increased cellular dihydrofolate reductase mRNA levels, and dihydrofolate reductase enzymatic activity was enhanced by UCN-01, roscovitine, olomoucine and p21, in transient transfection experiments. These results support a mechanism for the self-regulation of retinoblastoma expression, and point to the need to establish the appropriate dose of cyclin-dependent kinase inhibitors as antiproliferative agents in anticancer treatments.
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Affiliation(s)
- Silvia Peñuelas
- Department of Biochemistry and Molecular Biology, School of Pharmacy, University of Barcelona, Spain
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8
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Park KK, Rue SW, Lee IS, Kim HC, Lee IK, Ahn JD, Kim HS, Yu TS, Kwak JY, Heintz NH, Magae J, Chang YC. Modulation of Sp1-dependent transcription by a cis-acting E2F element in dhfr promoter. Biochem Biophys Res Commun 2003; 306:239-43. [PMID: 12788094 DOI: 10.1016/s0006-291x(03)00941-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The dihydrofolate reductase (dhfr) promoter contains cis-acting elements for Sp1 and E2F. Here we examined the cooperative regulation of dhfr gene transcription by Sp1 and E2F in human osteosarcoma cells, U2OS. Trichostatin A, an inhibitor of histone deacetylases, markedly stimulated dhfr promoter activity, a response that was enhanced by the deletion of an E2F element. In contrast, deletion of the dhfr Sp1 binding sites completely abolished promoter stimulation by trichostatin A. Cotransfection assays showed that activation of dhfr transcription by expression of E2F1/DP1 requires the reiterated Sp1 elements, whereas activation by Sp1 was enhanced by the deletion of the E2F element. Expression of HDAC1 with Sp1 suppressed promoter activity and suppression was not alleviated by coexpression of E2F1/DP1. These results suggest that HDAC1 acts through Sp1 to repress dhfr promoter activity, and that the E2F element modulates the activity of Sp1 at the dhfr promoter through a cis-acting mechanism.
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Affiliation(s)
- Kwan-Kyu Park
- Kidney Institute, Keimyung University School of Medicine, 700-712, Daegu, Republic of Korea
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Nicolás M, Noé V, Ciudad CJ. Transcriptional regulation of the human Sp1 gene promoter by the specificity protein (Sp) family members nuclear factor Y (NF-Y) and E2F. Biochem J 2003; 371:265-75. [PMID: 12513689 PMCID: PMC1223280 DOI: 10.1042/bj20021166] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2002] [Revised: 12/05/2002] [Accepted: 01/03/2003] [Indexed: 11/17/2022]
Abstract
We analysed in detail the minimal promoter of transcription factor Sp1, which extends 217 bp from the initiation of transcription. Within this sequence we identified putative binding sites for Sp1, nuclear factor Y (NF-Y), activator protein 2 ('AP-2'), CCAAT/enhancer-binding protein ('C/EBP') and E2F transcription factors. In one case, the boxes for Sp1 and NF-Y are overlapping. Gel-shift and supershift assays demonstrated specific binding of Sp1, Sp3 and NF-Y proteins. Transient transfections and luciferase assays revealed activation of the Sp1 minimal promoter upon overexpression of Sp1 itself, NF-Y and E2F. Whereas overexpression of NF-Y or E2F had an additive effect on Sp1 overexpression, the activation of Sp1 transcription due to Sp1 was counteracted by Sp3 overexpression. Mutagenesis analysis of the NFY/Sp1-overlapping box revealed that both factors compete for this box, and that when the NF-Y site of this overlapping box is specifically mutated there is an increase in Sp1 binding, thus increasing transcriptional activity. These results help to explain the complex regulation of the Sp1 gene, which depends on the relative amounts of Sp1, Sp3, E2F and NF-Y proteins in the cell.
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Affiliation(s)
- Marta Nicolás
- Department of Biochemistry and Molecular Biology, School of Pharmacy, University of Barcelona, E-08028 Barcelona, Spain
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Fung H, Bennett RA, Demple B. Key role of a downstream specificity protein 1 site in cell cycle-regulated transcription of the AP endonuclease gene APE1/APEX in NIH3T3 cells. J Biol Chem 2001; 276:42011-7. [PMID: 11555653 DOI: 10.1074/jbc.m106423200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Abasic (apurinic/apyrimidinic or AP) sites are a frequent type of DNA damage that threatens genetic stability. The predominant mammalian enzyme initiating repair of AP sites is the Ape1 AP endonuclease (also called Apex or Hap1), which also facilitates DNA binding by several transcription factors (Ref1 activity). We found that expression of the APE1 gene was coordinated with the cell cycle in murine NIH3T3 cells: APE1 mRNA levels rose after the G(1)-S transition and peaked approximately 4-fold higher in early to mid-S phase. The increased APE1 mRNA was the result of transcriptional activation rather than increased mRNA stability. Fusions of various APE1 promoter fragments to the chloramphenicol acetyltransferase CAT reporter gene indicated that APE1 expression depends on two transcription factor Sp1 binding sites within the promoter region. Mutation of these sites or of two CCAAT elements within the APE1 promoter, in conjunction with protein binding studies, demonstrated their specific roles. The Sp1 site upstream of the transcription start, together with an adjacent CCAAT element, establishes a protein-DNA complex required for basal transcription of APE1. The Sp1 site downstream of the transcription start was required for the response to cell growth. Because Ape1 is a dual function enzyme, its cell cycle-dependent expression might affect both DNA repair and the activity of various transcription factors as a function of the cell cycle.
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Affiliation(s)
- H Fung
- Department of Cancer Cell Biology, Harvard School of Public Health, Boston, Massachusetts 02115, USA
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11
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Black AR, Black JD, Azizkhan-Clifford J. Sp1 and krüppel-like factor family of transcription factors in cell growth regulation and cancer. J Cell Physiol 2001; 188:143-60. [PMID: 11424081 DOI: 10.1002/jcp.1111] [Citation(s) in RCA: 819] [Impact Index Per Article: 35.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The Sp/KLF family contains at least twenty identified members which include Sp1-4 and numerous krüppel-like factors. Members of the family bind with varying affinities to sequences designated as 'Sp1 sites' (e.g., GC-boxes, CACCC-boxes, and basic transcription elements). Family members have different transcriptional properties and can modulate each other's activity by a variety of mechanisms. Since cells can express multiple family members, Sp/KLF factors are likely to make up a transcriptional network through which gene expression can be fine-tuned. 'Sp1 site'-dependent transcription can be growth-regulated, and the activity, expression, and/or post-translational modification of multiple family members is altered with cell growth. Furthermore, Sp/KLF factors are involved in many growth-related signal transduction pathways and their overexpression can have positive or negative effects on proliferation. In addition to growth control, Sp/KLF factors have been implicated in apoptosis and angiogenesis; thus, the family is involved in several aspects of tumorigenesis. Consistent with a role in cancer, Sp/KLF factors interact with oncogenes and tumor suppressors, they can be oncogenic themselves, and altered expression of family members has been detected in tumors. Effects of changes in Sp/KLF factors are context-dependent and can appear contradictory. Since these factors act within a network, this diversity of effects may arise from differences in the expression profile of family members in various cells. Thus, it is likely that the properties of the overall network of Sp/KLF factors play a determining role in regulation of cell growth and tumor progression.
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Affiliation(s)
- A R Black
- Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, New York 14263, USA.
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12
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Nicolás M, Noé V, Jensen KB, Ciudad CJ. Cloning and characterization of the 5'-flanking region of the human transcription factor Sp1 gene. J Biol Chem 2001; 276:22126-32. [PMID: 11294852 DOI: 10.1074/jbc.m010740200] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The 5'-flanking region of the human Sp1 gene was cloned and characterized. Sequence analysis of this region showed the absence of both CAAT and TATA boxes and an initiator element. The proximal promoter of the Sp1 gene is a GC-rich region that contains multiple GC boxes and Ap2 binding sites. The major transcription start site is located 63 base pairs upstream of the translation start site. Transfection experiments demonstrate that all the elements necessary to achieve significant basal transcription activity are located between positions -443 and -20 relative to the translational start. Sp1 and Sp3 proteins bind to the downstream GC box located in the proximal promoter of Sp1. Furthermore, we demonstrate that the Sp1 protein activates Sp1 transcription activity; thus the Sp1 gene is autoregulated.
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Affiliation(s)
- M Nicolás
- Department of Biochemistry and Molecular Biology, School of Pharmacy, University of Barcelona, 08028 Barcelona, Spain
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13
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Noé V, Alemany C, Nicolás M, Ciudad CJ. Sp1 involvement in the 4beta-phorbol 12-myristate 13-acetate (TPA)-mediated increase in resistance to methotrexate in Chinese hamster ovary cells. EUROPEAN JOURNAL OF BIOCHEMISTRY 2001; 268:3163-73. [PMID: 11389717 DOI: 10.1046/j.1432-1327.2001.02198.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
4beta-Phorbol 12-myristate 13-acetate (TPA) increases the number of colonies resistant to methotrexate (MTX), mainly by amplification of the dihydrofolate reductase (dhfr) locus. We showed previously that inhibition of protein kinase C (PKC) prevents this resistance. Here, we studied the molecular changes involved in the development of TPA-mediated MTX resistance in Chinese hamster ovary (CHO) cells. TPA incubation increased the expression and activity of DHFR. Because Sp1 controls the dhfr promoter, we determined the effect of TPA on the expression of Sp1 and its binding to DNA. TPA incubation increased Sp1 binding and the levels of Sp1 protein. The latter effect was due to an increase in Sp1 mRNA. Dephosphorylation of nuclear extracts from control or TPA-treated cells reduced the binding of Sp1. Stable transfectants of PKCalpha showed increased Sp1 binding, and when treated with MTX, developed a greater number of resistant colonies than control cells. Seventy-five percent of the isolated colonies showed increased copy number for the dhfr gene. Transient expression of PKCalpha increased DHFR activity. Over-expression of Sp1 increased resistance to MTX, and inhibition of Sp1 binding by mithramycin decreased this resistance. We conclude that one mechanism by which TPA enhances MTX resistance, mainly by gene amplification, is through an increase in Sp1 expression which leads to DHFR activation.
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Affiliation(s)
- V Noé
- Department of Biochemistry and Molecular Biology, School of Pharmacy, University of Barcelona, Spain
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Onishi T, Yamakawa K, Franco OE, Kawamura J, Watanabe M, Shiraishi T, Kitazawa S. Mitogen-activated protein kinase pathway is involved in alpha6 integrin gene expression in androgen-independent prostate cancer cells: role of proximal Sp1 consensus sequence. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1538:218-27. [PMID: 11336792 DOI: 10.1016/s0167-4889(01)00068-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Metastatic diseases of prostate cancer reveal high expression of alpha6 integrin and the activation of mitogen-activated protein kinases (MAP kinase). Therefore, the present study was conducted to examine whether MAP kinase pathway is involved in the alpha6 integrin gene expression in androgen-independent prostate cancer cell lines. alpha6 integrin mRNA expression, the alpha6 integrin promoter-induced luciferase activities and MAP kinase enzyme activities in androgen-independent LNCaP and PC-3 cell lines were higher than those in androgen-dependent LNCaP. Deletion and mutation analysis showed that Sp1 consensus sequence at -48 to -43 bp from the transcription start site was necessary for basal promoter activity. Binding of Sp1 to its consensus sequence in three cell lines was confirmed by electrophoretic mobility shift assays. Sp1 binding to its consensus sequence, as well as promoter activity and mRNA expression, were found to be inhibited by an inhibitor of MAP kinase kinase 1 and 2, U0126, in the androgen-independent cell lines. Our results indicate that the proximal Sp1 is necessary for basal promoter activity of the alpha6 integrin, suggesting that signal transduction from MAP kinases to activation of Sp1 might be involved in alpha6 integrin gene expression in androgen-independent prostate cancer cell lines.
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Affiliation(s)
- T Onishi
- Department of Urology, Mie University School of Medicine, Japan
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15
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Chang YC, Illenye S, Heintz NH. Cooperation of E2F-p130 and Sp1-pRb complexes in repression of the Chinese hamster dhfr gene. Mol Cell Biol 2001; 21:1121-31. [PMID: 11158299 PMCID: PMC99566 DOI: 10.1128/mcb.21.4.1121-1131.2001] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2000] [Accepted: 11/05/2000] [Indexed: 11/20/2022] Open
Abstract
In mammalian cells reiterated binding sites for Sp1 and two overlapping and inverted E2F sites at the transcription start site regulate the dhfr promoter during the cell growth cycle. Here we have examined the contributions of the dhfr Sp1 and E2F sites in the repression of dhfr gene expression. In serum-starved cells or during serum stimulation, the Chinese hamster dhfr gene was not derepressed by trichostatin A (TSA), an inhibitor of histone deacetylases (HDAC). Immunoprecipitation experiments showed that HDAC1 and hypophosphorylated retinoblastoma protein (pRb) are associated with Sp1 in serum-starved CHOC400 cells. In transfection experiments, reporter plasmids containing the reiterated dhfr Sp1 sites were stimulated 10-fold by TSA, while a promoter containing four dhfr E2F sites and a TATA box was responsive to E2F but was completely unaffected by TSA. HDAC1 did not coprecipitate with p130-E2F DNA binding complexes, the predominant E2F binding activity in cell extracts after serum starvation, suggesting that p130 imposes a TSA-insensitive state on the dhfr promoter. In support of this notion, recruitment of GAL4-p130 to a dihydrofolate reductase-GAL4 reporter rendered the promoter insensitive to TSA, while repression by GAL4-pRb was sensitive to TSA. Upon phosphorylation of pRb and p130 after serum stimulation, the Sp1-pRb and p130-E2F interactions were lost while the Sp1-HDAC1 interaction persisted into S phase. Together these studies suggest a dynamic model for the cooperation of pRb and p130 in repression of dhfr gene expression during withdrawal from the cell cycle. We propose that, during initial phases of cell cycle withdrawal, the binding of dephosphorylated pRb to Sp1-HDAC1 complexes and complexes of E2F-1 -to -3 with DP results in transient, HDAC-dependent suppression of dhfr transcription. Upon withdrawal of cells into G(0), recruitment of p130 to E2F-4-DP-1 complexes at the transcription start site results in a TSA-insensitive complex that cooperates with Sp1-HDAC-pRb complexes to stably repress dhfr promoter activity in quiescent cells.
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Affiliation(s)
- Y C Chang
- Department of Pathology, University of Vermont College of Medicine, Burlington, Vermont 05405, USA
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16
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Alemany C, Noe V, Ciudad CJ. Identification by RNA-based arbitrarily primed PCR of the involvement of cytochrome c oxidase in the development of resistance to methotrexate. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1495:319-26. [PMID: 10699469 DOI: 10.1016/s0167-4889(99)00159-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
RNA-based arbitrarily primed PCR (RAP-PCR) was used to identify sequences in CHO K1 cells that were differentially expressed upon methotrexate incubation during the development of resistance to this drug. Ten different RAP products were isolated, cloned and sequenced. Among these, we identified one sequence that showed 84% identity with the nucleotide sequence of rat cytochrome c oxidase subunit II, and 90% identity with the amino acid sequence of this protein. This RAP fragment was up-regulated in a dose- and time-dependent manner. The overexpression of cytochrome c oxidase subunit II mRNA as a result of methotrexate incubation was corroborated by quantitative RT-PCR and Northern blot analysis. Incubation of cells with sodium azide, a specific cytochrome c oxidase inhibitor, decreased the number of resistant colonies after methotrexate treatment. Thus, overexpression of cytochrome c oxidase is involved in the development of resistance to methotrexate. These results suggest that sodium azide may be used as a modulator in chemotherapy with methotrexate.
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Affiliation(s)
- C Alemany
- Department of Biochemistry, Division IV, School of Pharmacy, University of Barcelona, Avda. Diagonal 643, E-08028, Barcelona, Spain
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Noé V, Ciudad CJ, Chasin LA. Effect of differential polyadenylation and cell growth phase on dihydrofolate reductase mRNA stability. J Biol Chem 1999; 274:27807-14. [PMID: 10488126 DOI: 10.1074/jbc.274.39.27807] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have constructed tetracycline-responsive dhfr minigenes and transferred them to a Chinese hamster ovary cell DHFR-deficient deletion mutant to obtained cells in which dhfr transcription can be repressed by tetracycline (tet-off). DHFR mRNA half-life measured after the repression of transcription by tetracycline in these transfectants is about 1.5 h, which is significantly shorter than previously reported. In addition, we observed that DHFR mRNA is less stable in serum-starved cells than in exponentially growing cells. Given that the dhfr gene contains multiple polyadenylation sites, we analyzed the role of polyadenylation site usage on the stability of the resultant mRNA molecules. We found that DHFR mRNA is more stable when a strong polyadenylation site is used. Finally, we have observed that the relative lengths of the poly(A) tails for the different DHFR mRNA species correlated with their relative stability in growing versus resting cells.
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Affiliation(s)
- V Noé
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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18
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Doetzlhofer A, Rotheneder H, Lagger G, Koranda M, Kurtev V, Brosch G, Wintersberger E, Seiser C. Histone deacetylase 1 can repress transcription by binding to Sp1. Mol Cell Biol 1999; 19:5504-11. [PMID: 10409740 PMCID: PMC84392 DOI: 10.1128/mcb.19.8.5504] [Citation(s) in RCA: 332] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The members of the Sp1 transcription factor family can act as both negative and positive regulators of gene expression. Here we show that Sp1 can be a target for histone deacetylase 1 (HDAC1)-mediated transcriptional repression. The histone deacetylase inhibitor trichostatin A activates the chromosomally integrated murine thymidine kinase promoter in an Sp1-dependent manner. Coimmunoprecipitation experiments with Swiss 3T3 fibroblasts and 293 cells demonstrate that Sp1 and HDAC1 can be part of the same complex. The interaction between Sp1 and HDAC1 is direct and requires the carboxy-terminal domain of Sp1. Previously we have shown that the C terminus of Sp1 is necessary for the interaction with the transcription factor E2F1 (J. Karlseder, H. Rotheneder, and E. Wintersberger, Mol. Cell. Biol. 16:1659-1667, 1996). Coexpression of E2F1 interferes with HDAC1 binding to Sp1 and abolishes Sp1-mediated transcriptional repression. Our results indicate that one component of Sp1-dependent gene regulation involves competition between the transcriptional repressor HDAC1 and the transactivating factor E2F1.
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Affiliation(s)
- A Doetzlhofer
- Institute of Molecular Biology, Vienna Biocenter, University of Vienna, Vienna, Austria
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Kumar AP, Butler AP. Enhanced Sp1 DNA-binding activity in murine keratinocyte cell lines and epidermal tumors. Cancer Lett 1999; 137:159-65. [PMID: 10374837 DOI: 10.1016/s0304-3835(98)00351-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Altered regulation of ornithine decarboxylase (ODC) is frequently observed in epidermal tumors. We have shown that the transcription factor Sp1 is one of the regulators of ODC expression and that Sp3 antagonizes this Sp1-mediated activation of ODC expression. These results led us to examine the levels and binding activity of Sp1 and Sp3 in nuclear extracts prepared from cultured murine keratinocytes, transformed keratinocyte cell lines and epidermal tumors. Here we show that the Sp1 DNA-binding activity is higher in established keratinocyte cell line extracts than in primary keratinocyte extracts. Sp1 message levels and Sp1 DNA-binding activity was found to be low in 20-week papillomas and high in squamous cell carcinomas. These results suggest that increased levels of Sp1 and enhanced Sp1 DNA binding activity are correlated with epidermal tumor progression. Based on these results, we propose that increased Sp1 DNA binding may augment the proliferative capacity of tumor cells through overexpression of Sp1-responsive genes, possibly including ODC.
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Affiliation(s)
- A P Kumar
- Department of Carcinogenesis, The University of Texas M.D. Anderson Cancer Center, Smithville 78957, USA.
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Black AR, Jensen D, Lin SY, Azizkhan JC. Growth/cell cycle regulation of Sp1 phosphorylation. J Biol Chem 1999; 274:1207-15. [PMID: 9880488 DOI: 10.1074/jbc.274.3.1207] [Citation(s) in RCA: 143] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Sp1 sites can mediate growth/cell cycle induction of dihydrofolate reductase in late G1 (Jensen, D. E., Black, A. R. Swick, A. G., and Azizkhan, J. C. (1997) J. Cell. Biochem. 67, 24-31). To investigate mechanisms underlying this induction, effects of serum stimulation on regulation of Sp1 were examined. In Balb/c 3T3 cells, serum stimulation did not affect Sp1 synthesis or the relative binding of Sp1 family members to DNA; however, it did result in a rapid, approximately 2-fold increase in Sp1 levels and an approximately 3-fold increase in specific Sp1 phosphorylation in mid-G1. In normal human diploid fibroblasts, serum stimulation also increased Sp1 phosphorylation in mid-G1 but did not affect Sp1 levels. Therefore, Sp1 phosphorylation is regulated in a growth/cell cycle-dependent manner which correlates temporally with induction of dihydrofolate reductase transcription. Further studies revealed a kinase activity specifically associated with Sp1 in a growth-regulated manner. This activity is distinct from purified kinases previously shown to phosphorylate Sp1 in vitro and phosphorylates Sp1 between amino acids 612 and 678 in its C terminus, a region also phosphorylated in mid-G1 in vivo. Therefore, this study indicates that phosphorylation of the C terminus of Sp1 may play a role in the cell cycle regulation of its transcriptional activity.
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Affiliation(s)
- A R Black
- Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, New York 14263, USA
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21
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Vallian S, Chin KV, Chang KS. The promyelocytic leukemia protein interacts with Sp1 and inhibits its transactivation of the epidermal growth factor receptor promoter. Mol Cell Biol 1998; 18:7147-56. [PMID: 9819401 PMCID: PMC109296 DOI: 10.1128/mcb.18.12.7147] [Citation(s) in RCA: 102] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/1998] [Accepted: 08/19/1998] [Indexed: 11/20/2022] Open
Abstract
The promyelocytic leukemia protein (PML) is a nuclear phosphoprotein with growth- and transformation-suppressing ability. Having previously shown it to be a transcriptional repressor of the epidermal growth factor receptor (EGFR) gene promoter, we have now shown that PML's repression of EGFR transcription is caused by inhibition of EGFR's Sp1-dependent activity. On functional analysis, the repressive effect of PML was mapped to a 150-bp element (the sequences between -150 and -16, relative to the ATG initiation site) of the promoter. Transient transfection assays with Sp1-negative Drosophila melanogaster SL2 cells showed that the transcription of this region was regulated by Sp1 and that the Sp1-dependent activity of the promoter was suppressed by PML in a dose-dependent manner. Coimmunoprecipitation and mammalian two-hybrid assays demonstrated that PML and Sp1 were associated in vivo. In vitro binding by means of the glutathione S-transferase (GST) pull-down assay, using the full-length and truncated GST-Sp1 proteins and in vitro-translated PML, showed that PML and Sp1 directly interacted and that the C-terminal (DNA-binding) region of Sp1 and the coiled-coil (dimerization) domain of PML were essential for this interaction. Analysis of the effects of PML on Sp1 DNA binding by electrophoretic mobility shift assay (EMSA) showed that PML could specifically disrupt the binding of Sp1 to DNA. Furthermore, cotransfection of PML specifically repressed Sp1, but not the E2F1-mediated activity of the dihydrofolate reductase promoter. Together, these data suggest that the association of PML and Sp1 represents a novel mechanism for negative regulation of EGFR and other Sp1 target promoters.
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Affiliation(s)
- S Vallian
- Division of Laboratory Medicine, The University of Texas, Anderson Cancer Center, Houston, Texas 77030, USA
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