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Wei L, Deng C, Zhang B, Wang G, Meng Y, Qin H. SP4 Facilitates Esophageal Squamous Cell Carcinoma Progression by Activating PHF14 Transcription and Wnt/Β-Catenin Signaling. Mol Cancer Res 2024; 22:55-69. [PMID: 37768180 PMCID: PMC10758695 DOI: 10.1158/1541-7786.mcr-22-0835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 06/13/2023] [Accepted: 09/25/2023] [Indexed: 09/29/2023]
Abstract
Specificity protein 4 transcription factor (SP4), a member of the Sp/Krüppel-like family (KLF), could bind to GT and GC box promoters, and plays an essential role in transcriptional activating. Despite SP4 having been detected to be highly expressed in a variety of human tumors, its biological effect and underlying molecular mechanism in esophageal squamous cell carcinoma (ESCC) remains unclear. Our research discovered that high SP4 expression is detected in primary ESCC specimens and cell lines and is strongly associated with the ESCC tumor grade and poor prognosis. In vitro, knockdown of SP4 suppressed cell proliferation and cell-cycle progression and promoted apoptosis, whereas overexpression of SP4 did the opposite. In vivo, inhibiting SP4 expression in ESCC cells suppresses tumor growth. Subsequently, we demonstrated that SP4 acts as the transcriptional upstream of PHF14, which binds to PHF14 promoter region, thus promoting PHF14 transcription. PHF14 was also significantly expressed in patient tissues and various ESCC cell lines and its expression promoted cell proliferation and inhibited apoptosis. Moreover, knockdown of SP4 inhibited the Wnt/β-catenin signaling pathway, whereas overexpression of PHF14 eliminated the effects of SP4 knockdown in ESCC cells. These results demonstrate that SP4 activates the Wnt/β-catenin signaling pathway by driving PHF14 transcription, thereby promoting ESCC progression, which indicates that SP4 might act as a prospective prognostic indicator or therapeutic target for patients with ESCC. IMPLICATIONS This study identified SP4/PH14 axis as a new mechanism to promote the progression of ESCC, which may serve as a novel therapeutic target for patients with ESCC.
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Affiliation(s)
- Li Wei
- Department of Surgery and Anesthesia, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province, China
| | - Chaowei Deng
- Department of Cell Biology and Genetics/Institute of Genetics and Developmental Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China
| | - Bo Zhang
- Department of Peripheral Vascular Disease, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province, China
| | - Guanghui Wang
- Department of General Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province, China
| | - Yan Meng
- Department of Peripheral Vascular Disease, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province, China
| | - Hao Qin
- Department of Peripheral Vascular Disease, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province, China
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The role of Sp3 transcription factor in syntaxin 1A gene silencing. GENE REPORTS 2022. [DOI: 10.1016/j.genrep.2022.101628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Pan LX, Li M, Zhao FY, Cheng FP, Wang ZL. Amsp3 may act upstream of Amdnmt3 in female caste differentiation in the honeybee (Apis mellifera). INSECT MOLECULAR BIOLOGY 2021; 30:532-540. [PMID: 34219310 DOI: 10.1111/imb.12723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 05/31/2021] [Accepted: 06/17/2021] [Indexed: 06/13/2023]
Abstract
In honey bees, the process of producing two female castes, including queens and workers, is nutritionally controlled by differential feeding royal jelly to newly emerged larvae. Although they have almost identical genetic blueprints, these castes show striking differences in their morphologies, longevities and reproductive capabilities. DNA methyltransferase 3 (Amdnmt3) gene is involved in the regulatory network for honeybee caste differentiation. Due to the role of two zinc fingers containing transcription factors, SP1 and SP3 in controlling mammalian Dnmts, this study aimed to determine a similar interaction of SPs with Amdnmt3 in the honeybee. We confirmed that the promoter region of Amdnmt3 contained multiple predicted SP1/SP3 binding sites and then investigated the role of AmSP3 in queen-worker differentiation network. We observed that the expression level of Amsp3 was significantly higher in worker larvae than that in queen larvae at 48 h, 84 h and 120 h. Knockdown of Amsp3 expression by RNAi in worker larvae significantly reduced the expression level of Amdnmt3 and caused morphological changes in adult bees towards a queen-like phenotype. However, the expression levels of Amsp3 and Amdnmt3 were repressed by juvenile hormone (JH). Our results suggest that AmSP3 is an important part of the queen-worker differentiation network and supports the role of Amdnmt3 in determining the phenotypic outcome of developing larvae.
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Affiliation(s)
- L-X Pan
- Honeybee Research Institute, Jiangxi Agricultural University, Nanchang, Jiangxi, 330045, China
- Jiangxi Province Key Laboratory of Honeybee Biology and Beekeeping, Jiangxi Agricultural University, Nanchang, Jiangxi, 330045, China
| | - M Li
- Honeybee Research Institute, Jiangxi Agricultural University, Nanchang, Jiangxi, 330045, China
- Jiangxi Province Key Laboratory of Honeybee Biology and Beekeeping, Jiangxi Agricultural University, Nanchang, Jiangxi, 330045, China
| | - F-Y Zhao
- Honeybee Research Institute, Jiangxi Agricultural University, Nanchang, Jiangxi, 330045, China
- Jiangxi Province Key Laboratory of Honeybee Biology and Beekeeping, Jiangxi Agricultural University, Nanchang, Jiangxi, 330045, China
| | - F-P Cheng
- Honeybee Research Institute, Jiangxi Agricultural University, Nanchang, Jiangxi, 330045, China
- Jiangxi Province Key Laboratory of Honeybee Biology and Beekeeping, Jiangxi Agricultural University, Nanchang, Jiangxi, 330045, China
| | - Z-L Wang
- Honeybee Research Institute, Jiangxi Agricultural University, Nanchang, Jiangxi, 330045, China
- Jiangxi Province Key Laboratory of Honeybee Biology and Beekeeping, Jiangxi Agricultural University, Nanchang, Jiangxi, 330045, China
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Li B, Xia Y, Lv J, Wang W, Xuan Z, Chen C, Jiang T, Fang L, Wang L, Li Z, He Z, Li Q, Xie L, Qiu S, Zhang L, Zhang D, Xu H, Xu Z. miR-151a-3p-rich small extracellular vesicles derived from gastric cancer accelerate liver metastasis via initiating a hepatic stemness-enhancing niche. Oncogene 2021; 40:6180-6194. [PMID: 34535770 DOI: 10.1038/s41388-021-02011-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 08/18/2021] [Accepted: 09/06/2021] [Indexed: 12/24/2022]
Abstract
Liver metastasis (LM) severely affects gastric cancer (GC) patients' prognosis. Small extracellular vesicles (sEVs) play key roles in intercellular communication. Specific sEV-miRNAs from several types of cancer were found to induce a premetastatic niche in target organs before tumor cell arrive. However, whether the primary GC affects hepatic microenvironment or the role of sEV-miRNAs in GC-LM is yet unclear. We report that GC-derived sEVs are primarily absorbed by Kupffer cells (KCs). sEV-miR-151a-3p is highly expressed in GC-LM patients' plasma and presents poor prognosis. Treating mice with sEVs-enriched in miR-151a-3p promotes GC-LM, whereas has no influence on the proliferation of GC cells in situ. Mechanistically, sEV-miR-151a-3p inhibits SP3 in KCs. Simultaneously, sEV-miR-151a-3p targets YTHDF3 to decrease the transcriptional inhibitory activity of SP3 by reducing SUMO1 translation in a N6-methyladenosine-dependent manner. These factors contribute to TGF-β1 transactivation in KCs, subsequently activating the SMAD2/3 pathway and enhancing the stem cell-like properties of incoming GC cells. Furthermore, sEV-miR-151a-3p induces miR-151a-3p transcription in KCs to form a positive feedback loop. In summary, our results reveal a previously unidentified regulatory axis initiated by sEV-miR-151a-3p that establishes a hepatic stemness-permissive niche to support GC-LM. sEV-miR-151a-3p could be a promising diagnostic biomarker and preventive treatment candidate for GC-LM.
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Affiliation(s)
- Bowen Li
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu Province, China
| | - Yiwen Xia
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu Province, China
| | - Jialun Lv
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu Province, China
| | - Weizhi Wang
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu Province, China
| | - Zhe Xuan
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu Province, China
| | - Cen Chen
- Department of Respiratory and Critical Care Medicine, Jinling Hospital, the First School of Clinical Medicine, Southern Medical University, Nanjing, 210002, Jiangsu Province, China
| | - Tianlu Jiang
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu Province, China
| | - Lang Fang
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu Province, China
| | - Linjun Wang
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu Province, China
| | - Zheng Li
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu Province, China
| | - Zhongyuan He
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu Province, China
| | - Qingya Li
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu Province, China
| | - Li Xie
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu Province, China
| | - Shengkui Qiu
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu Province, China.,Department of General Surgery, the Second Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu Province, China
| | - Lu Zhang
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu Province, China
| | - Diancai Zhang
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu Province, China
| | - Hao Xu
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu Province, China
| | - Zekuan Xu
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu Province, China. .,Jiangsu Key Lab of Cancer Biomarkers, Prevention and Treatment, Collaborative Innovation Center for Cancer Personalized Medicine, Nanjing Medical University, Nanjing, 211166, Jiangsu Province, China.
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Lee J, Jung E, Gestoso K, Heur M. ZEB1 Mediates Fibrosis in Corneal Endothelial Mesenchymal Transition Through SP1 and SP3. Invest Ophthalmol Vis Sci 2020; 61:41. [PMID: 32721022 PMCID: PMC7425726 DOI: 10.1167/iovs.61.8.41] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 06/21/2020] [Indexed: 11/24/2022] Open
Abstract
Purpose ZEB1 is induced during endothelial-mesenchymal transition (EnMT) in the cornea. Induction of SP1 and SP3 by ZEB1 along with identification of putative SP1 and SP3 binding sites in promoters of EnMT-associated gene lead us to investigate their roles in retrocorneal membrane formation in the corneal endothelium. Methods Expressions of SP1, SP3, and EnMT associated genes were analyzed by immunoblotting and semiquantitative reverse transcription polymerase chain reaction. Accell SMARTpool siRNAs targeting ZEB1, SP1, and SP3 were used for gene knockdown. SP1 and SP3 binding to promoters of EnMT associated genes was investigated by chromatin immunoprecipitation assay. Corneal endothelium in mice was surgically injured in vivo under direct visualization. Results Transient Fibroblast Growth Factor 2 stimulation increased the expression of both SP1 and SP3 in the human corneal endothelium ex vivo. ZEB1 siRNA knockdown inhibited FGF2-induced SP1 mRNA and protein but not the expression of SP3. FGF2-induced expression of EnMT-related genes, such as fibronectin, vimentin, and type I collagen, was reduced by both SP1 and SP3 siRNA knockdown, with inhibition of SP1 having a greater inhibitory effect than SP3. Additionally, although SP1 and SP3 proteins were found to bind together, SP1 and SP3 could bind to the same promoter binding sites of EnMT-related genes in the absence of the other. Moreover, siRNA knockdown of Zeb1 inhibited injury-dependent RCM formation in mouse corneal endothelium in vivo. Conclusions Zeb1, through SP1 and SP3, plays a central role in mesenchymal transition induced fibrosis in the corneal endothelium and suggests that Zeb1 could be targeted to inhibit anterior segment fibrosis.
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Affiliation(s)
- JeongGoo Lee
- USC Roski Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States
| | - Eric Jung
- USC Roski Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States
| | | | - Martin Heur
- USC Roski Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States
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Manu KA, Cao PHA, Chai TF, Casey PJ, Wang M. p21cip1/waf1 Coordinate Autophagy, Proliferation and Apoptosis in Response to Metabolic Stress. Cancers (Basel) 2019; 11:cancers11081112. [PMID: 31382612 PMCID: PMC6721591 DOI: 10.3390/cancers11081112] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 07/25/2019] [Accepted: 07/30/2019] [Indexed: 12/12/2022] Open
Abstract
Cancer cells possess metabolic properties that are different from benign cells. These unique characteristics have become attractive targets that are being actively investigated for cancer therapy. p21cip1/waf1, also known as Cyclin-Dependent Kinase inhibitor 1A, is encoded by the CDKN1A gene. It is a major p53 target gene involved in cell cycle progression that has been extensively evaluated. To date, p21 has been reported to regulate various cell functions, both dependent and independent of p53. Besides regulating the cell cycle, p21 also modulates apoptosis, induces senescence, and maintains cellular quiescence in response to various stimuli. p21 transcription is induced in response to stresses, including those from oxidative and chemotherapeutic treatment. A recent study has shown that in response to metabolic stresses such as nutrient and energy depletion, p21 expression is induced to regulate various cell functions. Despite the biological significance, the mechanism of p21 regulation in cancer adaptation to metabolic stress is underexplored and thus represents an exciting field. This review focuses on the recent development of p21 regulation in response to metabolic stress and its impact in inducing cell cycle arrest and death in cancer cells.
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Affiliation(s)
- Kanjoormana Aryan Manu
- Program in Cancer and Stem Cell Biology, Duke-NUS Graduate Medical School, Singapore 169857, Singapore
| | - Pham Hong Anh Cao
- Program in Cancer and Stem Cell Biology, Duke-NUS Graduate Medical School, Singapore 169857, Singapore
| | - Tin Fan Chai
- Program in Cancer and Stem Cell Biology, Duke-NUS Graduate Medical School, Singapore 169857, Singapore
| | - Patrick J Casey
- Program in Cancer and Stem Cell Biology, Duke-NUS Graduate Medical School, Singapore 169857, Singapore
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Mei Wang
- Program in Cancer and Stem Cell Biology, Duke-NUS Graduate Medical School, Singapore 169857, Singapore.
- Department of Biochemistry, National University of Singapore, Singapore 117596, Singapore.
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A CRISPR/Cas9 Functional Screen Identifies Rare Tumor Suppressors. Sci Rep 2016; 6:38968. [PMID: 27982060 PMCID: PMC5159885 DOI: 10.1038/srep38968] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 11/15/2016] [Indexed: 11/08/2022] Open
Abstract
An enormous amount of tumor sequencing data has been generated through large scale sequencing efforts. The functional consequences of the majority of mutations identified by such projects remain an open, unexplored question. This problem is particularly complicated in the case of rare mutations where frequency of occurrence alone or prediction of functional consequences are insufficient to distinguish driver from passenger or bystander mutations. We combine genome editing technology with a powerful mouse cancer model to uncover previously unsuspected rare oncogenic mutations in Burkitt's lymphoma. We identify two candidate tumor suppressors whose loss cooperate with MYC over-expression to accelerate lymphomagenesis. Our results highlight the utility of in vivo CRISPR/Cas9 screens combined with powerful mouse models to identify and validate rare oncogenic modifier events from tumor mutational data.
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Hedrick E, Cheng Y, Jin UH, Kim K, Safe S. Specificity protein (Sp) transcription factors Sp1, Sp3 and Sp4 are non-oncogene addiction genes in cancer cells. Oncotarget 2016; 7:22245-56. [PMID: 26967243 PMCID: PMC5008359 DOI: 10.18632/oncotarget.7925] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 02/23/2016] [Indexed: 12/31/2022] Open
Abstract
Specificity protein (Sp) transcription factor (TF) Sp1 is overexpressed in multiple tumors and is a negative prognostic factor for patient survival. Sp1 and also Sp3 and Sp4 are highly expressed in cancer cells and in this study, we have used results of RNA interference (RNAi) to show that the three TFs individually play a role in the growth, survival and migration/invasion of breast, kidney, pancreatic, lung and colon cancer cell lines. Moreover, tumor growth in athymic nude mice bearing L3.6pL pancreatic cancer cells as xenografts were significantly decreased in cells depleted for Sp1, Sp3 and Sp4 (combined) or Sp1 alone. Ingenuity Pathway Analysis (IPA) of changes in gene expression in Panc1 pancreatic cancer cells after individual knockdown of Sp1, Sp3 and Sp4 demonstrates that these TFs regulate genes and pathways that correlated with the functional responses observed after knockdown but also some genes and pathways that inversely correlated with the functional responses. However, causal IPA analysis which integrates all pathway-dependent changes in all genes strongly predicted that Sp1-, Sp3- and Sp4-regulated genes were associated with the pro-oncogenic activity. These functional and genomic results coupled with overexpression of Sp transcription factors in tumor vs. non-tumor tissues and decreased Sp1 expression with age indicate that Sp1, Sp3 and Sp4 are non-oncogene addiction (NOA) genes and are attractive drug targets for individual and combined cancer chemotherapies.
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Affiliation(s)
- Erik Hedrick
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX 77843, USA
| | - Yating Cheng
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX 77843, USA
| | - Un-Ho Jin
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX 77843, USA
| | - Kyounghyun Kim
- Environmental Health, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Stephen Safe
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX 77843, USA
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KIM YOUNGRANG, KANG TAEKWON, TO PHUONGKIM, NGUYEN NGUYENTHIXUAN, CHO YOUNGSEOK, JUNG CHAEYONG, KIM MINSOO. HOXB13-mediated suppression of p21WAF1/CIP1 regulates JNK/c-Jun signaling in prostate cancer cells. Oncol Rep 2016; 35:2011-6. [DOI: 10.3892/or.2016.4563] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 10/30/2015] [Indexed: 11/06/2022] Open
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Vizcaíno C, Mansilla S, Portugal J. Sp1 transcription factor: A long-standing target in cancer chemotherapy. Pharmacol Ther 2015; 152:111-24. [PMID: 25960131 DOI: 10.1016/j.pharmthera.2015.05.008] [Citation(s) in RCA: 250] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 05/04/2015] [Indexed: 11/25/2022]
Abstract
Sp1 (specificity protein 1) is a well-known member of a family of transcription factors that also includes Sp2, Sp3 and Sp4, which are implicated in an ample variety of essential biological processes and have been proven important in cell growth, differentiation, apoptosis and carcinogenesis. Sp1 activates the transcription of many cellular genes that contain putative CG-rich Sp-binding sites in their promoters. Sp1 and Sp3 proteins bind to similar, if not the same, DNA tracts and compete for binding, thus they can enhance or repress gene expression. Evidences exist that the Sp-family of proteins regulates the expression of genes that play pivotal roles in cell proliferation and metastasis of various tumors. In patients with a variety of cancers, high levels of Sp1 protein are considered a negative prognostic factor. A plethora of compounds can interfere with the trans-activating activities of Sp1 and other Sp proteins on gene expression. Several pathways are involved in the down-regulation of Sp proteins by compounds with different mechanisms of action, which include not only the direct interference with the binding of Sp proteins to their putative DNA binding sites, but also promoting the degradation of Sp protein factors. Down-regulation of Sp transcription factors and Sp1-regulated genes is drug-dependent and it is determined by the cell context. The acknowledgment that several of those compounds are safe enough might accelerate their introduction into clinical usage in patients with tumors that over-express Sp1.
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Affiliation(s)
- Carolina Vizcaíno
- Instituto de Biología Molecular de Barcelona, CSIC, Parc Científic de Barcelona, E-08028 Barcelona, Spain
| | - Sylvia Mansilla
- Instituto de Biología Molecular de Barcelona, CSIC, Parc Científic de Barcelona, E-08028 Barcelona, Spain
| | - José Portugal
- Instituto de Biología Molecular de Barcelona, CSIC, Parc Científic de Barcelona, E-08028 Barcelona, Spain.
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Cartilage tissue engineering: molecular control of chondrocyte differentiation for proper cartilage matrix reconstruction. Biochim Biophys Acta Gen Subj 2014; 1840:2414-40. [PMID: 24608030 DOI: 10.1016/j.bbagen.2014.02.030] [Citation(s) in RCA: 164] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2013] [Revised: 02/06/2014] [Accepted: 02/26/2014] [Indexed: 12/18/2022]
Abstract
BACKGROUND Articular cartilage defects are a veritable therapeutic problem because therapeutic options are very scarce. Due to the poor self-regeneration capacity of cartilage, minor cartilage defects often lead to osteoarthritis. Several surgical strategies have been developed to repair damaged cartilage. Autologous chondrocyte implantation (ACI) gives encouraging results, but this cell-based therapy involves a step of chondrocyte expansion in a monolayer, which results in the loss in the differentiated phenotype. Thus, despite improvement in the quality of life for patients, reconstructed cartilage is in fact fibrocartilage. Successful ACI, according to the particular physiology of chondrocytes in vitro, requires active and phenotypically stabilized chondrocytes. SCOPE OF REVIEW This review describes the unique physiology of cartilage, with the factors involved in its formation, stabilization and degradation. Then, we focus on some of the most recent advances in cell therapy and tissue engineering that open up interesting perspectives for maintaining or obtaining the chondrogenic character of cells in order to treat cartilage lesions. MAJOR CONCLUSIONS Current research involves the use of chondrocytes or progenitor stem cells, associated with "smart" biomaterials and growth factors. Other influential factors, such as cell sources, oxygen pressure and mechanical strain are considered, as are recent developments in gene therapy to control the chondrocyte differentiation/dedifferentiation process. GENERAL SIGNIFICANCE This review provides new information on the mechanisms regulating the state of differentiation of chondrocytes and the chondrogenesis of mesenchymal stem cells that will lead to the development of new restorative cell therapy approaches in humans. This article is part of a Special Issue entitled Matrix-mediated cell behaviour and properties.
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Priya A, Johar K, Wong-Riley MTT. Specificity protein 4 functionally regulates the transcription of NMDA receptor subunits GluN1, GluN2A, and GluN2B. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:2745-2756. [PMID: 23871830 DOI: 10.1016/j.bbamcr.2013.07.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 07/03/2013] [Accepted: 07/08/2013] [Indexed: 10/26/2022]
Abstract
N-Methyl-d-aspartate (NMDA) receptors are major glutamatergic receptors involved in most excitatory neurotransmission in the brain. The transcriptional regulation of NMDA receptors is not fully understood. Previously, we found that the GluN1 and GluN2B subunits of the NMDA receptor are regulated by nuclear respiratory factors 1 and 2 (NRF-1 and NRF-2). NRF-1 and NRF-2 also regulate all 13 subunits of cytochrome c oxidase (COX), a critical energy-generating enzyme, thereby coupling neuronal activity and energy metabolism at the transcriptional level. Specificity protein (Sp) is a family of transcription factors that bind to GC-rich regions, with Sp1, Sp3, and Sp4 all binding to the same cis- motifs. Sp1 and Sp3 are ubiquitously expressed, whereas Sp4 expression is restricted to neurons and testicular cells. Recently, we found that the Sp1 factor regulates all subunits of COX. The goal of the present study was to test our hypothesis that the Sp factors also regulate specific subunits of NMDA receptors, and that they function with NRF-1 and NRF-2 via one of three mechanisms: complementary, concurrent and parallel, or a combination of complementary and concurrent/parallel. By means of multiple approaches we found that Sp4 functionally regulated GluN1, GluN2A, and GluN2B, but not GluN2C. On the other hand, Sp1 and Sp3 did not regulate these subunits as previously thought. Our data suggest that Sp4 operates in a complementary and concurrent/parallel manner with NRF-1 and NRF-2 to mediate the tight coupling between energy metabolism and neuronal activity at the molecular level.
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Affiliation(s)
- Anusha Priya
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Kaid Johar
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Margaret T T Wong-Riley
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.
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A network of transcription factors operates during early tooth morphogenesis. Mol Cell Biol 2013; 33:3099-112. [PMID: 23754753 DOI: 10.1128/mcb.00524-13] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Improving the knowledge of disease-causing genes is a unique challenge in human health. Although it is known that genes causing similar diseases tend to lie close to one another in a network of protein-protein or functional interactions, the identification of these protein-protein networks is difficult to unravel. Here, we show that Msx1, Snail, Lhx6, Lhx8, Sp3, and Lef1 interact in vitro and in vivo, revealing the existence of a novel context-specific protein network. These proteins are all expressed in the neural crest-derived dental mesenchyme and cause tooth agenesis disorder when mutated in mouse and/or human. We also identified an in vivo direct target for Msx1 function, the cyclin D-dependent kinase (CDK) inhibitor p19(ink4d), whose transcription is differentially modulated by the protein network. Considering the important role of p19(ink4d) as a cell cycle regulator, these results provide evidence for the first time of the unique plasticity of the Msx1-dependent network of proteins in conferring differential transcriptional output and in controlling the cell cycle through the regulation of a cyclin D-dependent kinase inhibitor. Collectively, these data reveal a novel protein network operating in the neural crest-derived dental mesenchyme that is relevant for many other areas of developmental and evolutionary biology.
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Carver BJ, Plosa EJ, Stinnett AM, Blackwell TS, Prince LS. Interactions between NF-κB and SP3 connect inflammatory signaling with reduced FGF-10 expression. J Biol Chem 2013; 288:15318-25. [PMID: 23558680 DOI: 10.1074/jbc.m112.447318] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Inflammation inhibits normal lung morphogenesis in preterm infants. Soluble inflammatory mediators present in the lungs of patients developing bronchopulmonary dysplasia disrupt expression of multiple genes critical for development. However, the mechanisms linking innate immune signaling and developmental programs are not clear. NF-κB activation inhibits expression of the critical morphogen FGF-10. Here, we show that interactions between the RELA subunit of NF-κB and SP3 suppress SP1-mediated FGF-10 expression. SP3 co-expression reduced SP1-mediated Fgf-10 promoter activity, suggesting antagonistic interactions between SP1 and SP3. Chromatin immunoprecipitation of LPS-treated primary mouse fetal lung mesenchymal cells detected increased interactions between SP3, RELA, and the Fgf-10 promoter. Expression of a constitutively active IκB kinase β mutant not only decreased Fgf-10 promoter activity but also increased RELA-SP3 nuclear interactions. Expression of a dominant-negative IκB, which blocks NF-κB nuclear translocation, prevented inhibition of FGF-10 by SP3. The inhibitory functions of SP3 required sequences located in the N-terminal region of the protein. These data suggested that inhibition of FGF-10 by inflammatory signaling involves the NF-κB-dependent interactions between RELA, SP3, and the Fgf-10 promoter. NF-κB activation may therefore lead to reduced gene expression by recruiting inhibitory factors to specific gene promoters following exposure to inflammatory stimuli.
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Affiliation(s)
- Billy J Carver
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
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15
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Kasaai B, Gaumond MH, Moffatt P. Regulation of the bone-restricted IFITM-like (Bril) gene transcription by Sp and Gli family members and CpG methylation. J Biol Chem 2013; 288:13278-94. [PMID: 23530031 DOI: 10.1074/jbc.m113.457010] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND BRIL is a bone-specific membrane protein that is involved in osteogenesis imperfecta type V. RESULTS Bril transcription is activated by Sp1, Sp3, OSX, and GLI2 and by CpG demethylation. CONCLUSION Regulation of Bril involves trans-acting factors integrating at conserved promoter elements and epigenetic modifications. SIGNIFICANCE Identification of the mechanisms governing Bril transcription is important to understand its role in skeletal biology. Bril encodes a small membrane protein present in osteoblasts. In humans, a single recurrent mutation in the 5'-UTR of BRIL causes osteogenesis imperfecta type V. The exact function of BRIL and the mechanism by which it contributes to disease are still unknown. The goal of the current study was to characterize the mechanisms governing Bril transcription in humans, rats, and mice. In the three species, as detected by luciferase reporter assays in UMR106 cells, we found that most of the base-line regulatory activity was localized within ∼250 bp upstream of the coding ATG. Co-transfection experiments indicated that Sp1 and Sp3 were potent inducers of the promoter activity, through the binding of several GC-rich boxes. Osterix was a weak activator but acted cooperatively with Sp1 and GLI2 to synergistically induce the BRIL promoter. GLI2, a mediator of hedgehog signaling pathway, was also a potent activator of BRIL through a single GLI binding site. Correspondingly, agonists of the hedgehog pathway (purmorphamine and Indian hedgehog) in MC3T3 osteoblasts led to increased BRIL levels. The BRIL promoter activity was also found to be negatively modulated through two different mechanisms. First, the ZFP354C zinc finger protein repressed basal and Sp1-induced activity. Second, CpG methylation of the promoter region correlated with an inactive state and prevented Sp1 activation. The data provide the very first analyses of the cis- and trans-acting factors regulating Bril transcription. They revealed key roles for the Sp members and GLI2 that possibly cooperate to activate Bril when the promoter becomes demethylated.
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Affiliation(s)
- Bahar Kasaai
- Shriners Hospital for Children, Montreal, Quebec H3G 1A6, Canada
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16
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Noratto GD, Jutooru I, Safe S, Angel-Morales G, Mertens-Talcott SU. The drug resistance suppression induced by curcuminoids in colon cancer SW-480 cells is mediated by reactive oxygen species-induced disruption of the microRNA-27a-ZBTB10-Sp axis. Mol Nutr Food Res 2013; 57:1638-48. [PMID: 23471840 DOI: 10.1002/mnfr.201200609] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 01/05/2013] [Accepted: 01/08/2013] [Indexed: 12/14/2022]
Abstract
SCOPE Mechanisms involving the curcuminoids effects in decreasing the prooncogenic specificity protein (Sp) transcription factors, and Sp-regulated genes in SW-480 colon cancer cells and how the multidrug resistance protein (MDR1) inhibition is mediated by Sp suppression. METHODS AND RESULTS HT-29 and SW-480 colon cancer and normal CCD-18Co colon fibroblast cells were treated with curcuminoids previously analyzed by HPLC. Gene and protein expression regulation were assessed by RT-PCR, transfections with expression constructs, and Western blots. Curcuminoids (2.5-10 μg/mL) suppressed preferentially the growth of SW-480 and HT-29 compared to CCD-18Co cells and enhanced the anticancer activity of the chemotherapeutic drug 5-fluorouracil due to the suppression of MDR1. Additionally, Sp1, Sp3, and Sp4 and Sp-regulated genes were downregulated by curcuminoids in SW-480 and this was accompanied by suppression of microRNA-27a (miR-27a) and induction of ZBTB10, an mRNA target of miR-27a and a transcriptional repressor of Sp expression. This mechanism was mediated by the induction of ROS. RNA-interference and transfection with ZBTB10-expression plasmid demonstrated that MDR1 was regulated by Sp1 and Sp3 and the disruption of the miR-27a-ZBTB10-Sp axis. CONCLUSION Colon cancer treatment with curcuminoids will enhance the therapeutic effects of drugs in patients who have developed drug resistance.
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17
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Gromnicova R, Romero I, Male D. Transcriptional control of the multi-drug transporter ABCB1 by transcription factor Sp3 in different human tissues. PLoS One 2012; 7:e48189. [PMID: 23133566 PMCID: PMC3485001 DOI: 10.1371/journal.pone.0048189] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 09/24/2012] [Indexed: 11/13/2022] Open
Abstract
The ATP-binding cassette (ABC) transporter ABCB1, encoded by the multidrug resistance gene MDR1, is expressed on brain microvascular endothelium and several types of epithelium, but not on endothelia outside the CNS. It is an essential component of the blood-brain barrier. The aim of this study was to identify cell-specific controls on the transcription of MDR1 in human brain endothelium. Reporter assays identified a region of 500 bp around the transcription start site that was optimally active in brain endothelium. Chromatin immunoprecipitation identified Sp3 and TFIID associated with this region and EMSA (electrophoretic mobility shift assays) confirmed that Sp3 binds preferentially to an Sp-target site (GC-box) on the MDR1 promoter in brain endothelium. This result contrasts with findings in other cell types and with the colon carcinoma line Caco-2, in which Sp1 preferentially associates with the MDR1 promoter. Differences in MDR1 transcriptional control between brain endothelium and Caco-2 could not be explained by the relative abundance of Sp1:Sp3 nor by the ratio of Sp3 variants, because activating variants of Sp3 were present in both cell types. However differential binding of other transcription factors was also detected in two additional upstream regions of the MDR1 promoter. Identification of cell-specific controls on the transcription of MDR1 indicates that it may be possible to modulate multi-drug resistance on tumours, while leaving the blood brain barrier intact.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- Blood-Brain Barrier
- Caco-2 Cells
- Cell Line, Tumor
- Cell Separation
- Endothelial Cells/cytology
- Endothelium, Vascular/cytology
- Flow Cytometry
- Gene Expression Regulation
- Humans
- Immunohistochemistry/methods
- Microscopy, Fluorescence/methods
- Promoter Regions, Genetic
- Protein Binding
- Sp3 Transcription Factor/metabolism
- Transcription Factor TFIID/metabolism
- Transcription, Genetic
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Affiliation(s)
- Radka Gromnicova
- Department of Life, Health and Chemical Sciences, The Open University, Milton Keynes, Bucks, United Kingdom
| | - Ignacio Romero
- Department of Life, Health and Chemical Sciences, The Open University, Milton Keynes, Bucks, United Kingdom
| | - David Male
- Department of Life, Health and Chemical Sciences, The Open University, Milton Keynes, Bucks, United Kingdom
- * E-mail:
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18
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Lu HP, Li J, Mo WJ, Feng ZB. RNAi-mediated down-regulation of Sp3 gene expression inhibits proliferation of HepG2 cells. Shijie Huaren Xiaohua Zazhi 2012; 20:2595-2600. [DOI: 10.11569/wcjd.v20.i27.2595] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the effect of RNA interference (RNAi)-mediated gene silencing of specificity protein 3 (Sp3) on the proliferation of human hepatocellular carcinoma HepG2 cells.
METHODS: HepG2 cells were infected with a lentivirus expressing Sp3-siRNA, and the expression of Sp3 mRNA and protein was determined by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR), and Western blot and immunohistochemistry. Cell growth was evaluated by methyl thiazolyl tetrazolium (MTT) assay, and cell cycle progression was analyzed by flow cytometry.
RESULTS: Compared to control cells, the expression levels of Sp3 mRNA and protein were significantly lower in HepG2 cells transfected with the Sp3-siRNA (mRNA: 0.47 ± 0.05 vs 0.74 ± 0.08, 0.70 ± 0.16, F = 7.322, all P < 0.05; protein: 0.37 ± 0.08vs 0.83 ± 0.17, 0.66 ± 0.13, F = 8.442, all P < 0.05). MTT assay showed that the growth of cells transfected with the Sp3-siRNA was slower at 48 , 72 and 96 h (0.28 ± 0.18 vs 0.34 ± 0.19, 0.35 ± 0.07, F = 3.888; 0.57 ± 0.11 vs 0.84 ± 0.05, 0.74 ± 0.08, F = 12.721; 0.72 ± 18.1 vs 0.98 ± 0.05, 0.93 ± 0.9, F = 6.342, all P < 0.05). Flow cytometry analysis showed that the percentage of cells in G1 phase increased in cells transfected with the Sp3-siRNA.
CONCLUSION: Sp3 may play an important role in the growth of human hepatic cancer cells, and RNAi-induced Sp3 down-regulation could inhibit the growth of HepG2 cells in vitro.
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19
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Predictive value of Sp1/Sp3/FLIP signature for prostate cancer recurrence. PLoS One 2012; 7:e44917. [PMID: 23028678 PMCID: PMC3441693 DOI: 10.1371/journal.pone.0044917] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 08/09/2012] [Indexed: 01/20/2023] Open
Abstract
Prediction of prostate cancer prognosis is challenging and predictive biomarkers of recurrence remain elusive. Although prostate specific antigen (PSA) has high sensitivity (90%) at a PSA level of 4.0 ng/mL, its low specificity leads to many false positive results and considerable overtreatment of patients and its performance at lower ranges is poor. Given the histopathological and molecular heterogeneity of prostate cancer, we propose that a panel of markers will be a better tool than a single marker. We tested a panel of markers composed of the anti-apoptotic protein FLIP and its transcriptional regulators Sp1 and Sp3 using prostate tissues from 64 patients with recurrent and non-recurrent cancer who underwent radical prostatectomy as primary treatment for prostate cancer and were followed with PSA measurements for at least 5 years. Immunohistochemical staining for Sp1, Sp3, and FLIP was performed on these tissues and scored based on the proportion and intensity of staining. The predictive value of the FLIP/Sp1/Sp3 signature for clinical outcome (recurrence vs. non-recurrence) was explored with logistic regression, and combinations of FLIP/Sp1/Sp3 and Gleason score were analyzed with a stepwise (backward and forward) logistic model. The discrimination of the markers was identified by sensitivity-specificity analysis and the diagnostic value of FLIP/Sp1/Sp3 was determined using area under the curve (AUC) for receiver operator characteristic curves. The AUCs for FLIP, Sp1, Sp3, and Gleason score for predicting PSA failure and non-failure were 0.71, 0.66, 0.68, and 0.76, respectively. However, this increased to 0.93 when combined. Thus, the “biomarker signature” of FLIP/Sp1/Sp3 combined with Gleason score predicted disease recurrence and stratified patients who are likely to benefit from more aggressive treatment.
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20
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Farina AR, Cappabianca L, Ruggeri P, Di Ianni N, Ragone M, Merolle S, Sano K, Stracke ML, Horowitz JM, Gulino A, Mackay AR. Constitutive autotaxin transcription by Nmyc-amplified and non-amplified neuroblastoma cells is regulated by a novel AP-1 and SP-mediated mechanism and abrogated by curcumin. FEBS Lett 2012; 586:3681-91. [PMID: 22975311 DOI: 10.1016/j.febslet.2012.08.026] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 08/11/2012] [Accepted: 08/24/2012] [Indexed: 01/26/2023]
Abstract
The motility, angiogenesis and metastasis-stimulating factor Autotaxin (Atx), over expressed by human neuroblastomas (NB), is constitutively expressed by human Nmyc-amplified SK-N-BE and non-Nmyc-amplified SH-SY5Y NB cells. Here, we characterise a novel Atx transcriptional mechanism, utilised by both cell lines, that is restricted to the first 285bp of the Atx promoter and involves AP-1 and SP transcription factors, acting through a CRE/AP-1-like element at position -142 to -149 and a GAbox at position -227 to -235 relative to the Atx translational start site. This novel transcriptional mechanism can be inhibited by internally initiated SP-3 and the natural phenol curcumin.
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Affiliation(s)
- Antonietta R Farina
- Section of Molecular Pathology, Department of Experimental Medicine, University of L'Aquila, 67100 L'Aquila, Italy
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21
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Chadalapaka G, Jutooru I, Sreevalsan S, Pathi S, Kim K, Chen C, Crose L, Linardic C, Safe S. Inhibition of rhabdomyosarcoma cell and tumor growth by targeting specificity protein (Sp) transcription factors. Int J Cancer 2012; 132:795-806. [PMID: 22815231 DOI: 10.1002/ijc.27730] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 06/08/2012] [Indexed: 12/30/2022]
Abstract
Specificity protein (Sp) transcription factors Sp1, Sp3 and Sp4 are highly expressed in rhabdomyosarcoma (RMS) cells. In tissue arrays of RMS tumor cores from 71 patients, 80% of RMS patients expressed high levels of Sp1 protein, whereas low expression of Sp1 was detected in normal muscle tissue. The non-steroidal anti-inflammatory drug (NSAID) tolfenamic acid (TA) inhibited growth and migration of RD and RH30 RMS cell lines and also inhibited tumor growth in vivo using a mouse xenograft (RH30 cells) model. The effects of TA were accompanied by downregulation of Sp1, Sp3, Sp4 and Sp-regulated genes in RMS cells and tumors, and the role of Sp protein downregulation in mediating inhibition of RD and RH30 cell growth and migration was confirmed by individual and combined knockdown of Sp1, Sp3 and Sp4 proteins by RNA interference. TA treatment and Sp knockdown in RD and RH30 cells also showed that four genes that are emerging as individual drug targets for treating RMS, namely c-MET, insulin-like growth factor receptor (IGFR), PDGFRα and CXCR4, are also Sp-regulated genes. These results suggest that NSAIDs such as TA may have potential clinical efficacy in drug combinations for treating RMS patients.
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Affiliation(s)
- Gayathri Chadalapaka
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX 77843-4466, USA
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22
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BnRCH gene inhibits cell growth of Hela cells through increasing the G2 phase of cell cycle. Hum Cell 2011; 24:150-60. [PMID: 22038067 DOI: 10.1007/s13577-011-0036-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 10/04/2011] [Indexed: 10/15/2022]
Abstract
The ubiquitin-proteasome pathway (UPP) is an important protein degradation system universally existing in eukaryotic organisms from yeast to human. In this system, hundreds of E3 ubiquitin-protein ligases are most important because they provide the substrate specificity and control many cellular processes. UPP has been found to be relevant to cancer development. BnRCH, the protein product from a novel gene isolated from Brassica napus, also has E3 ubiquitin-protein ligase activity. In order to exploit its potential use, human cervical carcinoma cell Hela (Hela cells) was transiently and stably transfected with BnRCH. The experimental results demonstrated: (1) in Hela cells, BnRCH inhibited the cell growth of Hela cells and increased their sensitivity to the anti-cancer chemotherapeutic drug cisplatin; and (2) the growth inhibition effect of BnRCH in Hela cells was found due to G2 phase cell cycle arrest with the transcriptional up-regulation of p21 (waf1/cip1), rather than apoptosis. This research suggests BnRCH has potential use in cancer therapy.
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23
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Sen S, Bunda S, Shi J, Wang A, Mitts TF, Hinek A. Retinoblastoma protein modulates the inverse relationship between cellular proliferation and elastogenesis. J Biol Chem 2011; 286:36580-91. [PMID: 21880723 DOI: 10.1074/jbc.m111.269944] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mechanism that leads to the inverse relationship between heightened cellular proliferation and the cessation of elastic fibers production, observed during formation of the arterial occlusions and dermal scars, is not fully understood. Because the retinoblastoma protein (Rb), responsible for cell cycle initiation, has also been implicated in insulin-like growth factor-I-mediated signaling stimulating elastin gene activation, we explored whether differential phosphorylation of Rb by various cyclin·cyclin-dependent kinase complexes would be responsible for promoting either elastogenic or pro-proliferative signals. We first tested cultures of dermal fibroblasts derived from Costello syndrome patients, in which heightened proliferation driven by mutated oncogenic H-Ras coincides with inhibition of elastogenesis. We found that Costello syndrome fibroblasts display elevated level of Rb phosphorylation on serine 780 (Ser(P)-780-Rb) and that pharmacological inhibition of Ras with radicicol, Mek/Erk with PD98059, or cyclin-dependent kinase 4 with PD0332991 not only leads to down-regulation of Ser(P)-780-Rb levels but also enhances Rb phosphorylation on threonine-821 (Thr(P)-821-Rb), which coincides with the recovery of elastin production. Then we demonstrated that treatment of normal skin fibroblasts with the pro-proliferative PDGF BB also up-regulates Ser(P)-780-Rb levels, but treatment with the pro-elastogenic insulin-like growth factor-I activates cyclinE-cdk2 complex to phosphorylate Rb on Thr-821. Importantly, we have established that elevation of Thr(P)-821-Rb promotes Rb binding to the Sp1 transcription factor and that successive binding of the Rb-Sp1 complex to the retinoblastoma control element within the elastin gene promoter stimulates tropoelastin transcription. In summary, we provide novel insight into the role of Rb in mediating the inverse relationship between elastogenesis and cellular proliferation.
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Affiliation(s)
- Sanjana Sen
- Cardiovascular Research, The Hospital for Sick Children, University of Toronto Toronto M5G 1X8, Canada
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24
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Karolczak-Bayatti M, Loughney AD, Robson SC, Europe-Finner GN. Epigenetic modulation of the protein kinase A RIIα (PRKAR2A) gene by histone deacetylases 1 and 2 in human smooth muscle cells. J Cell Mol Med 2011; 15:94-108. [PMID: 19818097 PMCID: PMC3822497 DOI: 10.1111/j.1582-4934.2009.00927.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Recently we reported that the expression of the protein kinase A (PKA) regulatory subunit RIIα is dynamically regulated in human smooth muscle cells of the uterus. We showed that expression levels of mRNA/protein were substantially increased during pregnancy and decreased upon labour, changes that were mirrored by particulate type II PKA activity. This implied an important role for RIIα in maintaining uterine quiescence during pregnancy. Consequently the purpose of the present study was to identify potential mechanisms by which expression of the RIIα gene was regulated in this tissue. We indicate here that the three SpI-III (GC) binding domains within the proximal promoter region of the human RIIα gene may play important roles in modulating expression of the gene in human myometrial cells. We show that all three GC binding domains are involved in binding Sp1, Sp3, histone deacetylase (HDACs) 1/2 and RbAp48 transcriptional complexes. The functional significance of these binding domains was further analysed employing in vitro luciferase reporter assays with full-length/truncated RIIα promoter constructs. Importantly we show that treatment of primary human myometrial cell cultures with the general class I/II HDAC inhibitor trichostatin A results in an increase in mRNA/protein levels. Moreover the increase in mRNA levels appeared to be preceded by an increase in aH3, PolIIa, Sp3 and HDAC 2 binding to the three SpI-III (GC) binding sites within the RIIα promoter. These results enable us to provide a model whereby RIIα expression is epigenetically regulated in human myometrial smooth muscle cells by histone deacetylase(s) activity within the GC-rich proximal promoter region of the gene.
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Affiliation(s)
- Magdalena Karolczak-Bayatti
- Institute of Cellular Medicine, Newcastle University, Faculty of Medical Sciences, Framlington Place, Newcastle upon Tyne, UK.
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25
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Landreville S, Vigneault F, Bergeron MA, Leclerc S, Gaudreault M, Morcos M, Mouriaux F, Salesse C, Guérin SL. Suppression of α5 gene expression is closely related to the tumorigenic properties of uveal melanoma cell lines. Pigment Cell Melanoma Res 2011; 24:643-55. [PMID: 21592318 DOI: 10.1111/j.1755-148x.2011.00869.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Cancer aggressiveness is related to the ability of cancer cells to escape the anchorage dependency toward the extracellular matrix, a process regulated by the integrin α5β1 and its ligand fibronectin. Here, we characterized the expression of the α5 gene in human uveal melanoma cell lines with distinct tumorigenic properties and investigated some of the mechanisms underlying the variations of their malignancy. Strong and weak expression of α5 was observed in cells with no (T108/T115) and high (T97/T98) tumorigenic properties, respectively. Expression and DNA binding of the transcription factors Sp1, activator protein 1 (AP-1) (both acting as activators), and nuclear factor I (NFI) (a strong repressor) to the α5 promoter were demonstrated in all cell lines. A reduced expression of AP-1 combined with a dramatic increase in NFI correlated with the suppression of α5 expression in T97 and T98 cells. Restoring α5 expression in T97 cells entirely abolished their tumorigenicity in immunodeficient mice. These uveal melanoma cell lines might therefore prove particularly useful as cellular models to investigate α5β1 function in the pathogenesis of invasive uveal melanoma.
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Affiliation(s)
- Solange Landreville
- Department of Ophthalmology & Visual Sciences, Washington University School of Medicine, St. Louis, MO, USA
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26
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Changes in gene expression induced by Sp1 knockdown differ from those caused by challenging Sp1 binding to gene promoters. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2011; 1809:327-36. [PMID: 21684359 DOI: 10.1016/j.bbagrm.2011.06.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Revised: 04/20/2011] [Accepted: 06/03/2011] [Indexed: 11/21/2022]
Abstract
C/G-rich DNA regions, which include those recognized by the Sp1 transcription factor in several gene promoters, also encompass potential binding sites for the DNA-intercalating anthracyclines doxorubicin and WP631. We explored the differences between changes in gene expression caused by the ability of these drugs to compete with Sp1 for binding to DNA and those produced by Sp1 knockdown. By quantitative RT-PCR of around 100 genes, most of them involved in control of cell cycle progression, we found that the treatment of human MDA-MB231 breast carcinoma cells with bis-anthracycline WP631 for 24 h produced a profile of gene down-regulation markedly different from the profile caused by doxorubicin treatment or by stable Sp1 knockdown. These observations are rationalized by considering a near-specific effect of WP631 on Sp1 interaction with several gene promoters, thus representing potential therapeutic targets for WP631, in contrast to a less specific effect of reducing the availability of Sp1 through RNA interference. Genes down-regulated upon each treatment were mapped to their molecular and biological functions, which documented the down-regulation, among other things, of genes involved in mRNA transcription regulation, granting us insights into the effects of challenging the transactivation of gene expression by Sp1.
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Jackson B, Brown SJ, Avilion AA, O'Shaughnessy RFL, Sully K, Akinduro O, Murphy M, Cleary ML, Byrne C. TALE homeodomain proteins regulate site-specific terminal differentiation, LCE genes and epidermal barrier. J Cell Sci 2011; 124:1681-90. [PMID: 21511732 DOI: 10.1242/jcs.077552] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The epidermal barrier varies over the body surface to accommodate regional environmental stresses. Regional skin barrier variation is produced by site-dependent epidermal differentiation from common keratinocyte precursors and often manifests as site-specific skin disease or irritation. There is strong evidence for body-site-dependent dermal programming of epidermal differentiation in which the epidermis responds by altering expression of key barrier proteins, but the underlying mechanisms have not been defined. The LCE multigene cluster encodes barrier proteins that are differentially expressed over the body surface, and perturbation of LCE cluster expression is linked to the common regional skin disease psoriasis. LCE subclusters comprise genes expressed variably in either external barrier-forming epithelia (e.g. skin) or in internal epithelia with less stringent barriers (e.g. tongue). We demonstrate here that a complex of TALE homeobox transcription factors PBX1, PBX2 and Pknox (homologues of Drosophila Extradenticle and Homothorax) preferentially regulate external rather than internal LCE gene expression, competitively binding with SP1 and SP3. Perturbation of TALE protein expression in stratified squamous epithelia in mice produces external but not internal barrier abnormalities. We conclude that epidermal barrier genes, such as the LCE multigene cluster, are regulated by TALE homeodomain transcription factors to produce regional epidermal barriers.
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Affiliation(s)
- Ben Jackson
- Centre for Cutaneous Research, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, UK
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Culver C, Melvin A, Mudie S, Rocha S. HIF-1α depletion results in SP1-mediated cell cycle disruption and alters the cellular response to chemotherapeutic drugs. Cell Cycle 2011; 10:1249-60. [PMID: 21412054 DOI: 10.4161/cc.10.8.15326] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Hypoxia inducible factor (HIF) is the major transcription factor involved in the regulation of the cellular response to hypoxia, or low oxygen tensions. Even though HIF-1 function is mostly studied following hypoxic stress, well oxygenated areas of several diseased tissues have detectable levels of this transcription factor. Therefore, it is surprising how little is known about the function of HIF in normoxia. This study seeks to fill this gap. Using transient HIF-1α knockdown, as well as, stable cell lines generated using short hairpin RNAs (shRNA), we have further characterized the role of HIF-1α in normoxia. Our data reveals that knockdown of HIF-1α results in a significant increase in cells in the G1 phase of the cell cycle. We find that HIF-1α depletion increases the protein and mRNA of both p21 and p27. p21 is induced via, at least in part, p53-independent but SP1-dependent mechanisms. Interestingly, HIF-1α knockdown also alters the cellular response to chemotherapeutic agents. These data have important implications in not only for the further understanding of HIF-1α, a major transcription factor, but also for the use of HIF-targeted and combination therapies in cancer treatment.
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Affiliation(s)
- Carolyn Culver
- College of Life Sciences, Wellcome Trust Centre for Gene Regulation and Expression, MSI/WTB/JBC Complex, University of Dundee, Dundee, Scotland, UK
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Tasseva G, Cole L, Vance JE. N-Myc and SP regulate phosphatidylserine synthase-1 expression in brain and glial cells. J Biol Chem 2010; 286:1061-73. [PMID: 21068393 DOI: 10.1074/jbc.m110.158709] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Phosphatidylserine (PS) is an essential constituent of biological membranes and plays critical roles in apoptosis and cell signaling. Because no information was available on transcriptional mechanisms that regulate PS biosynthesis in mammalian cells, we investigated the regulation of expression of the mouse PS synthase-1 (Pss1) gene. The Pss1 core promoter was characterized in vitro and in vivo through gel shift and chromatin immunoprecipitation assays. Transcription factor-binding sites, such as a GC-box cluster that binds Sp1/Sp3/Sp4 and N-Myc, and a degenerate E-box motif that interacts with Tal1 and E47, were identified. Pss1 transactivation was higher in brain of neonatal mice than in other tissues, consistent with brain being a major site of expression of Pss1 mRNA and PSS1 activity. Enzymatic assays revealed that PSS1 activity is enriched in primary cortical astrocytes compared with primary cortical neurons. Site-directed mutagenesis of binding sites within the Pss1 promoter demonstrated that Sp and N-Myc synergistically activate Pss1 expression in astrocytes. Chromatin immunoprecipitation indicated that Sp1, Sp3, and Sp4 interact with a common DNA binding site on the promoter. Reduction in levels of Sp1, Sp3, or N-Myc proteins by RNA interference decreased promoter activity. In addition, disruption of Sp/DNA binding with mithramycin significantly reduced Pss1 expression and PSS1 enzymatic activity, underscoring the essential contribution of Sp factors in regulating PSS1 activity. These studies provide the first analysis of mechanisms that regulate expression of a mammalian Pss gene in brain.
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Affiliation(s)
- Guergana Tasseva
- Department of Medicine, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
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Yu DCW, Waby JS, Chirakkal H, Staton CA, Corfe BM. Butyrate suppresses expression of neuropilin I in colorectal cell lines through inhibition of Sp1 transactivation. Mol Cancer 2010; 9:276. [PMID: 20950431 PMCID: PMC2974727 DOI: 10.1186/1476-4598-9-276] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Accepted: 10/15/2010] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Neuropilin is a transmembrane receptor for vascular endothelial growth factor (VEGF) and is expressed in normal endothelial cells and upregulated in cancer cells. Neuropilin-1 (NRP-1) has been shown to promote tumour cell migration and survival in colon cancer in response to VEGF binding. The expression profiles of neuropilins, associated co-receptors and known ligands have been mapped in three colorectal cell lines: Caco-2, HCT116 & HT29. We have previously shown that butyrate, a naturally occurring histone deacetylase inhibitor (HDACi) produced by fermentation of fibre in the colon, causes apoptosis of colon cancer cell lines. RESULTS Here we demonstrate that butyrate down-regulates NRP-1 and VEGF at the mRNA and protein level in colorectal cancer cell lines. NRP-1 is a known transcriptional target of Sp1, whose activity is regulated by acetylation. NRP-1 down-regulation by butyrate was associated with decreased binding affinity of Sp1 for canonical Sp-binding sites in the NRP-1 promoter. siRNA-mediated knock-down of Sp1 implied that Sp1 may have strong DNA binding activity but weak transactivation potential. CONCLUSION The downregulation of the key apoptotic and angiogenesis regulator NRP-1 by butyrate suggests a novel contributory mechanism to the chemopreventive effect of dietary fibre.
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Affiliation(s)
- Danny C W Yu
- Department of Oncology, School of Medicine and Biomedical Sciences, University of Sheffield, Royal Hallamshire Hospital, Sheffield, S10 2JF, UK
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Zelko IN, Mueller MR, Folz RJ. CpG methylation attenuates Sp1 and Sp3 binding to the human extracellular superoxide dismutase promoter and regulates its cell-specific expression. Free Radic Biol Med 2010; 48:895-904. [PMID: 20079429 PMCID: PMC2838251 DOI: 10.1016/j.freeradbiomed.2010.01.007] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Revised: 11/09/2009] [Accepted: 01/05/2010] [Indexed: 01/01/2023]
Abstract
Extracellular superoxide dismutase (EC-SOD) plays an important role in maintaining normal redox homeostasis in the lung. It is expressed at very high levels in pulmonary fibroblasts, alveolar type II epithelial cells, and smooth muscle cells. The molecular mechanisms governing this cell-specific expression of EC-SOD are mostly unknown. In our previous studies we showed that EC-SOD cell-specific expression was not attributable to differential transcriptional regulation, suggesting that other, possibly epigenetic, mechanisms are involved in regulation of its expression. In this paper, we show high levels of promoter methylation in A549 cells and correspondingly low levels of methylation in MRC5 cells. Inhibition of DNA methyltransferase activity by 5-azacytidine in A549 cells reactivated EC-SOD transcription (2.75+/-0.16-fold, P<0.001), demonstrating the importance of methylation in the repression of EC-SOD expression. Furthermore, methylation of cytosines in the promoter markedly decreased Sp1/Sp3-driven promoter activity to 30.09+/-2.85% (P<0.001) compared to unmethylated promoter. This attenuation of transcription of the promoter/reporter construct was, at least in part, attributable to the binding of the methyl-binding protein MeCP2 in the insect cells. However, no binding of MeCP2 or MBD2 protein to the EC-SOD promoter was detected in mammalian cells in vivo. We also found marked differences in the chromatin organization of the EC-SOD promoter between these two cell lines, further supporting the important role epigenetic modifications play in the regulation of EC-SOD expression.
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Affiliation(s)
- Igor N Zelko
- Department of Medicine, University of Louisville, KY 40202, USA.
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Yin H, Nichols TD, Horowitz JM. Transcription of mouse Sp2 yields alternatively spliced and sub-genomic mRNAs in a tissue- and cell-type-specific fashion. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2010; 1799:520-31. [PMID: 20353838 DOI: 10.1016/j.bbagrm.2010.03.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Accepted: 03/22/2010] [Indexed: 01/02/2023]
Abstract
The Sp-family of transcription factors is comprised by nine members, Sp1-9, that share a highly conserved DNA-binding domain. Sp2 is a poorly characterized member of this transcription factor family that is widely expressed in murine and human cell lines yet exhibits little DNA-binding or trans-activation activity in these settings. As a prelude to the generation of a "knock-out" mouse strain, we isolated a mouse Sp2 cDNA and performed a detailed analysis of Sp2 transcription in embryonic and adult mouse tissues. We report that (1) the 5' untranslated region of Sp2 is subject to alternative splicing, (2) Sp2 transcription is regulated by at least two promoters that differ in their cell-type specificity, (3) one Sp2 promoter is highly active in nine mammalian cell lines and strains and is regulated by at least five discrete stimulatory and inhibitory elements, (4) a variety of sub-genomic messages are synthesized from the Sp2 locus in a tissue- and cell-type-specific fashion and these transcripts have the capacity to encode a novel partial-Sp2 protein, and (5) RNA in situ hybridization assays indicate that Sp2 is widely expressed during mouse embryogenesis, particularly in the embryonic brain, and robust Sp2 expression occurs in neurogenic regions of the post-natal and adult brain.
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Affiliation(s)
- Haifeng Yin
- Department of Molecular Biomedical Sciences and the Center for Comparative Medicine and Translational Research, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606, USA
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Singh AK, Battu A, Mohareer K, Hasnain SE, Ehtesham NZ. Transcription of human resistin gene involves an interaction of Sp1 with peroxisome proliferator-activating receptor gamma (PPARgamma). PLoS One 2010; 5:e9912. [PMID: 20360975 PMCID: PMC2848011 DOI: 10.1371/journal.pone.0009912] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Accepted: 02/26/2010] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Resistin is a cysteine rich protein, mainly expressed and secreted by circulating human mononuclear cells. While several factors responsible for transcription of mouse resistin gene have been identified, not much is known about the factors responsible for the differential expression of human resistin. METHODOLOGY/PRINCIPAL FINDING We show that the minimal promoter of human resistin lies within approximately 80 bp sequence upstream of the transcriptional start site (-240) whereas binding sites for cRel, CCAAT enhancer binding protein alpha (C/EBP-alpha), activating transcription factor 2 (ATF-2) and activator protein 1 (AP-1) transcription factors, important for induced expression, are present within sequences up to -619. Specificity Protein 1(Sp1) binding site (-276 to -295) is also present and an interaction of Sp1 with peroxisome proliferator activating receptor gamma (PPARgamma) is necessary for constitutive expression in U937 cells. Indeed co-immunoprecipitation assay demonstrated a direct physical interaction of Sp1 with PPARgamma in whole cell extracts of U937 cells. Phorbol myristate acetate (PMA) upregulated the expression of resistin mRNA in U937 cells by increasing the recruitment of Sp1, ATF-2 and PPARgamma on the resistin gene promoter. Furthermore, PMA stimulation of U937 cells resulted in the disruption of Sp1 and PPARgamma interaction. Chromatin immunoprecipitation (ChIP) assay confirmed the recruitment of transcription factors phospho ATF-2, Sp1, Sp3, PPARgamma, chromatin modifier histone deacetylase 1 (HDAC1) and the acetylated form of histone H3 but not cRel, C/EBP-alpha and phospho c-Jun during resistin gene transcription. CONCLUSION Our findings suggest a complex interplay of Sp1 and PPARgamma along with other transcription factors that drives the expression of resistin in human monocytic U937 cells.
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Affiliation(s)
| | - Aruna Battu
- National Institute of Nutrition, Indian Council for Medical Research, Hyderabad, India
| | | | - Seyed E. Hasnain
- University of Hyderabad, Hyderabad, India
- Institute of Life Sciences, University of Hyderabad, Hyderabad, India
- Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
| | - Nasreen Z. Ehtesham
- National Institute of Nutrition, Indian Council for Medical Research, Hyderabad, India
- Institute of Life Sciences, University of Hyderabad, Hyderabad, India
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Kilareski EM, Shah S, Nonnemacher MR, Wigdahl B. Regulation of HIV-1 transcription in cells of the monocyte-macrophage lineage. Retrovirology 2009; 6:118. [PMID: 20030845 PMCID: PMC2805609 DOI: 10.1186/1742-4690-6-118] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Accepted: 12/23/2009] [Indexed: 12/20/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) has been shown to replicate productively in cells of the monocyte-macrophage lineage, although replication occurs to a lesser extent than in infected T cells. As cells of the monocyte-macrophage lineage become differentiated and activated and subsequently travel to a variety of end organs, they become a source of infectious virus and secreted viral proteins and cellular products that likely initiate pathological consequences in a number of organ systems. During this process, alterations in a number of signaling pathways, including the level and functional properties of many cellular transcription factors, alter the course of HIV-1 long terminal repeat (LTR)-directed gene expression. This process ultimately results in events that contribute to the pathogenesis of HIV-1 infection. First, increased transcription leads to the upregulation of infectious virus production, and the increased production of viral proteins (gp120, Tat, Nef, and Vpr), which have additional activities as extracellular proteins. Increased viral production and the presence of toxic proteins lead to enhanced deregulation of cellular functions increasing the production of toxic cellular proteins and metabolites and the resulting organ-specific pathologic consequences such as neuroAIDS. This article reviews the structural and functional features of the cis-acting elements upstream and downstream of the transcriptional start site in the retroviral LTR. It also includes a discussion of the regulation of the retroviral LTR in the monocyte-macrophage lineage during virus infection of the bone marrow, the peripheral blood, the lymphoid tissues, and end organs such as the brain. The impact of genetic variation on LTR-directed transcription during the course of retrovirus disease is also reviewed.
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Affiliation(s)
- Evelyn M Kilareski
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, 245 N 15th St, Philadelphia, Pennsylvania 19102, USA
- Center for Molecular Therapeutics and Resistance, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, 245 N 15th St, Philadelphia, Pennsylvania 19102, USA
- Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 19129, USA
| | - Sonia Shah
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, 245 N 15th St, Philadelphia, Pennsylvania 19102, USA
- Center for Molecular Therapeutics and Resistance, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, 245 N 15th St, Philadelphia, Pennsylvania 19102, USA
- Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 19129, USA
| | - Michael R Nonnemacher
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, 245 N 15th St, Philadelphia, Pennsylvania 19102, USA
- Center for Molecular Therapeutics and Resistance, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, 245 N 15th St, Philadelphia, Pennsylvania 19102, USA
- Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 19129, USA
| | - Brian Wigdahl
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, 245 N 15th St, Philadelphia, Pennsylvania 19102, USA
- Center for Molecular Therapeutics and Resistance, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, 245 N 15th St, Philadelphia, Pennsylvania 19102, USA
- Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 19129, USA
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A potent enhancer element in the 5′-UTR intron is crucial for transcriptional regulation of the human ubiquitin C gene. Gene 2009; 448:88-101. [DOI: 10.1016/j.gene.2009.08.013] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2009] [Revised: 08/26/2009] [Accepted: 08/28/2009] [Indexed: 02/01/2023]
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Jeckel KM, Limesand S, Anthony R. Specificity protein-1 and -3 trans-activate the ovine placental lactogen gene promoter. Mol Cell Endocrinol 2009; 307:118-24. [PMID: 19389461 PMCID: PMC2700009 DOI: 10.1016/j.mce.2009.04.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Revised: 04/10/2009] [Accepted: 04/15/2009] [Indexed: 12/17/2022]
Abstract
The proximal promoter (-383/+16) of the ovine placental lactogen (oPL) gene provides trophoblast-specific expression in vitro. Footprint 6 (FP6; -319/-349) lies within this region, and transfection of two-base pair mutations across FP6 into BeWo cells identified potential binding sites for CCAAT-enhancer binding protein (CEBP) and specificity proteins (Sp). Transfection of CEBP dominant negative or over-expression constructs did not impact transactivation of the proximal promoter. However, Sp1 and Sp3 over-expression constructs increased (p<or=0.05) transactivation. Additionally, Sp1 and Sp3 short-hairpin RNA constructs reduced (p<or=0.01) transactivation of the proximal promoter. In EMSA supershift assays, Sp1 and Sp3 antibodies were able to inhibit migration of the complexes formed with nuclear extracts from BeWo cells and ovine chorionic binucleate cells (oBNC). Furthermore, Southwestern analysis of oBNC nuclear extracts identified a nuclear protein corresponding with Sp3, identified by Western analysis. In conclusion, these results indicate that Sp1 and Sp3 are capable of interacting with FP6 of the oPL gene proximal promoter and function to enhance its transactivation.
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Affiliation(s)
| | | | - R.V. Anthony
- Corresponding Author: Russell V. Anthony, Ph.D. ARBL-Foothills Campus, 1683 Campus Delivery, Colorado State University, Fort Collins, CO 80523-1683, Telephone: (970) 491-2586, Facsimile: (970) 491-3557, e-mail:
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Transcriptional control of occludin expression in vascular endothelia: Regulation by Sp3 and YY1. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2009; 1789:175-84. [DOI: 10.1016/j.bbagrm.2009.01.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Transcription of the chicken Grin1 gene is regulated by the activity of SP3 and NRSF in undifferentiated cells and neurons. Biosci Rep 2008; 28:177-88. [PMID: 18557703 DOI: 10.1042/bsr20080058] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The NMDA (N-methyl-D-aspartate) receptors are important in the regulation of neuronal development, synaptic plasticity, learning and memory, and are involved in several brain pathologies. The NR1 subunit is essential for the assembly of functional receptors, as it forms the calcium-permeable ion channel and contains the obligatory co-agonist binding site. Previous studies have shown that NR1 gene (Grin1) expression is up-regulated during neuronal differentiation and its expression is widespread in the central nervous system. We have previously cloned the chicken Grin1 gene and 1.9 kb of the 5'-regulatory region. In the present study, we analysed the molecular mechanisms that regulate chicken Grin1 gene transcription in undifferentiated cells and neurons. By functional analysis of chicken Grin1-luciferase gene 5'-regulatory region constructs, we demonstrate that the basal promoter is delimited within 210 bp upstream from the main transcription initiation site. DNA-protein binding and functional assays revealed that the 5'-UTR (untranslated region) has one consensus NRSE (neuron-restrictive silencing element) that binds NRSF (neuron-restrictive silencing factor), and one SP (stimulating protein transcription factor) element that binds SP3, both repressing Grin1 gene transcription in undifferentiated P19 cells (embryonic terato-carcinoma cells) and PC12 cells (phaeochromocytoma cells). The promoter region lacks a consensus TATA box, but contains one GSG/SP (GSG-like box near a SP-consensus site) that binds SP3 and up-regulates gene transcription in embryonic chicken cortical neurons. Taken together, these results demonstrate a dual role of SP3 in regulating the expression of the Grin1 gene, by repressing transcription in the 5'-UTR in undifferentiated cells as well as acting as a transcription factor, increasing Grin1 gene transcription in neurons.
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Chen X, Yang J, Sung DY, Thompson W, Walker W, Thomas K. Molecular and functional characterization of the murine ldh2 promoter region: Sp-binding GC-box domains are the key cis-elements regulating ldh2 gene expression during spermatogenesis. Mol Cell Endocrinol 2008; 295:10-7. [PMID: 18790003 DOI: 10.1016/j.mce.2008.08.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2007] [Revised: 08/13/2008] [Accepted: 08/15/2008] [Indexed: 11/16/2022]
Abstract
The goal of the present study was to elucidate the specific transcriptional mechanisms that regulate ldh2 gene expression during the early stages of spermatogenesis. DNA sequence analysis of the 1.0-kb ldh2 promoter region directly upstream of the transcriptional start site indicated the presence of three SP-protein binding GC-box elements and the absence of TATA and CAAT boxes. Functional characterization studies of the mouse ldh2 promoter were performed in the SV40 transformed mouse spermatogonial cell line, GC-1 spg. Transfection/transient expression studies using full-length and truncated ldh2 promoter/luciferase reporter constructs revealed that all three of the SP-binding cis-regulatory GC-box elements are required for optimal ldh2 promoter activity. Additional site-directed mutagenesis studies indicated that the two most proximal GC-box sites play essential regulatory roles in mediating basal ldh2 promoter activity. These studies suggest that the expression of the ldh2 gene in spermatogonia and early spermatocytes are regulated by SP-mediated transcriptional mechanisms.
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Affiliation(s)
- Xing Chen
- Department of Anatomy and Neurobiology, Morehouse School of Medicine, Atlanta, GA 30310, United States
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Su HW, Wang SW, Ghishan FK, Kiela PR, Tang MJ. Cell confluency-induced Stat3 activation regulates NHE3 expression by recruiting Sp1 and Sp3 to the proximal NHE3 promoter region during epithelial dome formation. Am J Physiol Cell Physiol 2008; 296:C13-24. [PMID: 19064501 DOI: 10.1152/ajpcell.00263.2008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Activation of signal transducer and activator of transcription-3 (Stat3) during cell confluency is related to its regulatory roles in cell growth arrest- or survival-related physiological or developmental processes. We previously demonstrated that this signaling event triggers epithelial dome formation by transcriptional augmentation of sodium hydrogen exchanger-3 (NHE3) expression. However, the detailed molecular mechanism remained unclear. By using serial deletions, site-directed mutagenesis, and EMSA analysis, we now demonstrate Stat3 binding to an atypical Stat3-response element in the rat proximal NHE3 promoter, located adjacent to a cluster of Sp cis-elements (SpA/B/C), within -77/-36 nt of the gene. SpB (-58/-55 nt) site was more effective than SpA (-72/-69 nt) site for cooperative binding of Sp1/Sp3. Increasing cell density had no effect on Sp1/Sp3 expression but resulted in their increased binding to the SpA/B/C probe along with Stat3 and concurrently with enhanced nuclear pTyr705-Stat3 level. Immunoprecipitation performed with the nuclear extracts demonstrated physical interaction of Stat3 and Sp1/Sp3 triggered by cell confluency. Stat3 inhibition by overexpression of dominant-negative Stat3-D mutant in MDCK cells or by small interfering RNA-mediated knockdown in Caco-2 cells resulted in inhibition of the cell density-induced NHE3 expression, Sp1/Sp3 binding, and NHE3 promoter activity and in decreased dome formation. Thus, during confluency, ligand-independent Stat3 activation leads to its interaction with Sp1/Sp3, their recruitment to the SpA/B/C cluster in a Stat3 DNA-binding domain-dependent fashion, increased transcription, and expression of NHE3, to coordinate cell density-mediated epithelial dome formation.
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Affiliation(s)
- Hsiao-Wen Su
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, 1 Univ. Road, Tainan 70101, Taiwan
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Cellular transcription factors Sp1 and Sp3 suppress varicella-zoster virus origin-dependent DNA replication. J Virol 2008; 82:11723-33. [PMID: 18815296 DOI: 10.1128/jvi.01322-08] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The varicella-zoster virus (VZV) origin of DNA replication (oriS) contains a 46-bp AT-rich palindrome and three consensus binding sites for the VZV origin binding protein (OBP) encoded by VZV ORF51. All three OBP binding sites are upstream of the palindrome in contrast to the sequence of the herpes simplex virus oriS, which has required OBP binding sites upstream and downstream of the AT-rich region. We are investigating the roles that sequences downstream of the palindrome play in VZV oriS-dependent DNA replication. Computer analysis identified two GC boxes, GC box 1 and GC box 2, in the downstream region which were predicted to be binding sites for the cellular transcription factor Sp1. Electrophoretic mobility shift assay and supershift assays showed that two members of the Sp family (Sp1 and Sp3) stably bind to GC box 1, but not to GC box 2. A predicted binding site for the cellular factor Yin Yang 1 (YY1) that overlaps with GC box 2 was also identified. Supershift and mutational analyses confirmed the binding of YY1 to this site. Mutation of GC box 1 resulted in loss of Sp1 and Sp3 binding and an increase in origin-dependent replication efficiency in DpnI replication assays. In contrast, mutation of the YY1 site had a statistically insignificant effect. These results suggest a model where origin-dependent DNA replication and viral transcription are coupled by the binding of Sp1 and Sp3 to the downstream region of the VZV replication origin during lytic infection. They may also have implications regarding establishment or reactivation of viral latency.
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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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Abstract
In eukaryotes, gene expression is controlled by a relatively small number of regulators. Post-translational modifications dramatically increase the functional possibilities of those regulators. Modification of many transcription factors and cofactors by SUMO (small ubiquitin-related modifier) correlates, in most cases, with inhibition of transcription. Recent studies suggest a model whereby SUMO conjugation to transcription factors promotes the recruitment of co-repressors through direct protein-protein interaction with the SUMO protein. HDACs (histone deacetylases) are important, but not exclusive, effectors of SUMO-mediated repression. Sp3 (specificity protein 3), a zinc-finger DNA-binding domain transcription factor, has the ability to both activate and repress transcription in a context-dependent manner. SUMOylation regulates the dual nature of Sp3 function. Current data suggest that Sp3 represses transcription in a SUMO-dependent manner but independent of HDACs. Recent studies to identify additional co-repressors associated with SUMO and further investigate regulated activity of Sp3 are providing a deeper understanding of SUMO-dependent mechanisms of transcriptional regulation.
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Stielow B, Sapetschnig A, Krüger I, Kunert N, Brehm A, Boutros M, Suske G. Identification of SUMO-Dependent Chromatin-Associated Transcriptional Repression Components by a Genome-wide RNAi Screen. Mol Cell 2008; 29:742-54. [PMID: 18374648 DOI: 10.1016/j.molcel.2007.12.032] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2007] [Revised: 10/26/2007] [Accepted: 12/24/2007] [Indexed: 11/18/2022]
Affiliation(s)
- Bastian Stielow
- Institute of Molecular Biology and Tumor Research, Philipps-University of Marburg, Emil-Mannkopff-Strasse 2, D-35032 Marburg, Germany
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Chandran NS, Vunnava P, Wu Y, Kapatos G. Specificity proteins Sp1 and Sp3 interact with the rat GTP cyclohydrolase I proximal promoter to regulate transcription. J Neurochem 2008; 104:1233-48. [PMID: 18004997 PMCID: PMC2265209 DOI: 10.1111/j.1471-4159.2007.05054.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The role of the proximal promoter GC-box in regulating basal and cAMP-dependent GTP Cyclohydrolase I gene transcription was investigated using a variety of cell lines and techniques. These studies show that the GC-box is composed of a triad of cis-elements that in vitro bind specificity proteins Sp1 and Sp3. Sp1 and Sp3 were found associated with the native proximal promoter in PC12 cells but were not recruited to the promoter during cAMP-dependent transcription. Studies using Drosophila SL2 cells showed that Sp3 occupies two sites within the GC-box and enhances transcription when acting alone and synergistically when combined with nuclear factor-Y (NF-Y) and CCAAT/Enhancer-Binding Protein (C/EBP)beta, cognate binding proteins for the adjacent cAMP response element (CRE) and CCAAT-box cAMP response elements. In contrast, Sp1 bound only one site within the GC-box and did not enhance transcription unless combined with NF-Y and C/EBPbeta. Studies in SL2 cells also showed that Sp1 and Sp3 do not co-occupy the GC-box, and accordingly Sp1 competes for Sp3 binding to repress Sp3-dependent transcription. In PC12 cells, complete mutation of the GC-box reduced basal but not cAMP-dependent transcription, resulting in an overall increase in the cAMP response and demonstrating that formation of this enhanceosome does not require Sp1 or Sp3. Experiments in which the GC-box was replaced with a Gal4 element and the promoter challenged with Gal4 fusion proteins support this conclusion and a role for Sp3 in maintaining high levels of basal transcription in PC12 cells. Equivalent amounts of Sp1 and Sp3 were found associated with the native proximal promoter in PC12 and Rat2 cells, which differ 10-fold in basal transcription. Similar levels of methylation of CpG dinucleotides located within the GC-box were also observed in these two cells lines. These results suggest that Sp1 and Sp3 bound to the GC-box might help to preserve an open chromatin configuration at the proximal promoter in cells which constitutively express low levels of GTP Cyclohydrolase I.
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Affiliation(s)
- Nitya Sarath Chandran
- Cellular and Clinical Neurobiology Program, Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Prashanthi Vunnava
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, Michigan, USA
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Yanning Wu
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, Michigan, USA
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Gregory Kapatos
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, Michigan, USA
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, Michigan, USA
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Zelko IN, Mueller MR, Folz RJ. Transcription factors sp1 and sp3 regulate expression of human extracellular superoxide dismutase in lung fibroblasts. Am J Respir Cell Mol Biol 2008; 39:243-51. [PMID: 18314536 DOI: 10.1165/rcmb.2007-0378oc] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The molecular mechanisms that govern the transcription of human extracellular superoxide dismutase (EC-SOD), the major extracellular antioxidant enzyme, are largely unknown. To elucidate the mechanisms involved in human EC-SOD gene regulation and expression, we localized multiple transcription start sites to a finite region located 3.9 kb upstream of the ATG initiation codon. Within this segment, we subcloned a 2.7-kb fragment upstream of a luciferase reporter gene; the resulting construct exhibited strong in vivo promoter activity in two lung-derived cell lines. Deletion analysis of the EC-SOD 5'-flanking sequences identified a minimal 0.3-kb region that had strong basal promoter activity. Computer sequence analysis revealed a putative Sp1-like binding site within the EC-SOD proximal promoter region that lacked a TATA-box and showed a high frequency of GC nucleotides. Binding of Sp1 and Sp3 transcription factors to the EC-SOD promoter was confirmed by DNase I footprint analysis, electophoretic mobility shift assay, and competition and supershift assays. Cotransfection of the EC-SOD promoter-luciferase reporter constructs with plasmids encoding Sp1 and Sp3 into Sp-deficient insect SL2 cells showed strong activation of luciferase gene expression. The occupancy of the EC-SOD promoter by Sp1/Sp3 and RNA polymerase II in vivo was determined by chromatin immunoprecipitation assay and correlated well with levels of EC-SOD expression in lung epithelial cells (A549) and pulmonary fibroblasts (MRC5). Collectively, our results demonstrate the important role Sp1 and Sp3 plays in regulating the expression of human EC-SOD in the lung.
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Affiliation(s)
- Igor N Zelko
- Department of Medicine, University of Louisville, Louisville, Kentucky, USA
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47
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Whitten C, Swygert S, Butler SE, Finco TS. Transcription of the LAT gene is regulated by multiple binding sites for Sp1 and Sp3. Gene 2008; 413:58-66. [PMID: 18343609 DOI: 10.1016/j.gene.2008.01.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2007] [Revised: 01/29/2008] [Accepted: 01/31/2008] [Indexed: 11/18/2022]
Abstract
The LAT gene encodes an adaptor molecule that links receptor engagement to critical downstream signaling events. Previously, we identified the proximal promoter for the human LAT gene and found that it contains binding sites for members of the Ets and Runx transcription factor families. In the present study, we show that the promoter also contains 5 GC-rich elements that contribute to promoter activity and that are capable of binding the transcription factors Sp1 and Sp3. Overexpression of either Sp1 or full-length Sp3 was shown to augment LAT promoter activity, while siRNA-mediated knockdown of each transcription factor was demonstrated to have an inhibitory effect. We also discovered a cell-type specific DNase hypersensitive site that maps to the Sp1/Sp3 and adjacent Ets and Runx binding sites. Collectively, these results provide compelling data that implicates Sp1 and Sp3 in the transcriptional regulation of the human LAT gene.
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Affiliation(s)
- Caitlyn Whitten
- Agnes Scott College, Department of Biology, 141 E. College Ave., Decatur, GA 30030, USA
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48
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Pagès G. Sp3-mediated VEGF regulation is dependent on phosphorylation by extra-cellular signals regulated kinases (Erk). J Cell Physiol 2008; 213:454-63. [PMID: 17685427 DOI: 10.1002/jcp.21104] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We have previously demonstrated that phosphorylation by Erk of Sp1 was essential for its full activity in the context of the VEGF promoter. Here, we show that Sp3, which, as Sp1, belongs to the GC-rich binding transcription factor family, is also phosphorylated by Erk in vitro on serine 73. We have established cell lines in which expression of wild-type Sp3 or a serine 73 to alanine (S73A) mutant is controlled by tetracycline. One of these cells lines also express the Raf:ER chimera which permits stimulation of Erk by tamoxifen. Difference in electrophoretic mobility and antibody directed against the phosphorylated serine 73 demonstrate that it is phosphorylated in vivo. Wild-type Sp3 half-life is increased upon Erk activation but the S73 is poorly implicated in this mechanism suggesting that Erk-dependent Sp3 stability depends on other(s) domain(s) of the protein. Electro-mobility shift assays and utilization of Gal4/Sp3 chimeric proteins show that Erk does not alter Sp3 DNA binding capacity but enhances its transcriptional activity. The S73A mutant Sp3 posses a reduced activity in Erk-stimulated cells. In the inducible cell lines, expression of wild-type form of Sp3 increases VEGF production whereas the S73A form has a reduced potential reflecting its lower transcriptional activity. Altogether our results described a new link between constitutive Erk activity and the regulation of VEGF expression two common denominators implicated in tumor angiogenesis.
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Affiliation(s)
- Gilles Pagès
- Institute of Signalling, Developmental Biology and Cancer Research UMR CNRS 6543, University of Nice-Sophia Antipolis Equipe labellisée Ligue Nationale contre le Cancer, France.
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49
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Mansilla S, Portugal J. Sp1 transcription factor as a target for anthracyclines: effects on gene transcription. Biochimie 2008; 90:976-87. [PMID: 18226599 DOI: 10.1016/j.biochi.2007.12.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2007] [Accepted: 12/27/2007] [Indexed: 11/28/2022]
Abstract
The analysis of how anthracyclines interfere with DNA-protein complexes, and the evaluation of their effects on gene transcription, can promote the development of new more specific anti-tumour agents. Daunorubicin and the bisintercalating anthracycline WP631 (which binds more tightly to DNA) have been compared for their ability to inhibit Sp1-DNA interactions and gene transcription. WP631 is more efficient at inhibiting transcription initiation from promoters containing an Sp1-binding site, and it is a potent inhibitor of Sp1-activated transcription both in vitro and in human cell lines. The analysis of gene expression profiles using arrays, which include several genes containing Sp1-putative binding sites, suggests that changes in the transcriptome induce cell cycle arrest and drive a time-dependent response of cells to death stimuli through distinct pathways, which rely on the anthracycline used and its concentration.
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Affiliation(s)
- Sylvia Mansilla
- Instituto de Biologia Molecular de Barcelona, CSIC, Parc Cientific de Barcelona, Josep Samitier 1-5, E-08028 Barcelona, Spain
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50
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Baugé C, Beauchef G, Leclercq S, Kim SJ, Pujol JP, Galéra P, Boumédiene K. NFkappaB mediates IL-1beta-induced down-regulation of TbetaRII through the modulation of Sp3 expression. J Cell Mol Med 2007; 12:1754-66. [PMID: 18053089 PMCID: PMC3918091 DOI: 10.1111/j.1582-4934.2007.00173.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/29/2022] Open
Abstract
We previously showed that interleukin-1beta (IL-1beta) down-regulation of type II TGFbeta receptor (TbetaRII) involves NFkappaB pathway and requires de novo synthesis of a yet unknown protein. Here, we demonstrate that this effect is mediated through Sp1 site located at position -25 of human TbetaRII promoter. Inhibition of transcription factors binding (decoy oligonucleotides or mithramycin) abolished IL-1beta effect. EMSA and ChIP revealed that this treatment induced Sp3 binding to cis-sequence whereby IL-1beta exerts its transcriptional effects whereas it decreased that of Sp1. Moreover, although the cytokine did not modulate Sp1 expression, it increased that of Sp3 via NFkappaB pathway. Experiments of gain and loss of function clearly showed that Sp3 inhibited TbetaRII expression whereas its silencing abolished IL-1beta effect. In addition, both Sp1 and Sp3 were found to interact with NFkappaB, which therefore may indirectly interact with TbetaRII pro moter. Altogether, these data suggest that IL-1beta decreases TbetaRII expression by inducing Sp3 via NFkappaB and its binding on core promote at the expense of Sp1, which could explain the loss of cell responsiveness in certain conditions. These findings bring new insights in the knowledge of the interference between two antagonistic transduction pathways involved in multiple physiopathological processes.
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Affiliation(s)
- C Baugé
- Laboratory of Connective Tissue Biochemistry, University of Caen, Caen, France
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