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Lytras A, Detillieux K, Cattini PA. Identification of functional CCAAT/enhancer-binding protein and Ets protein binding sites in the human chorionic somatomammotropin enhancer sequences. J Mol Endocrinol 2011; 47:179-93. [PMID: 21737519 DOI: 10.1530/jme-11-0025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The human chorionic somatomammotropin (CS) A and B genes (listed as CSH1 and CSH2 in the HUGO database) are highly expressed in placenta. A 241 bp potent enhancer, nucleotides (nts) 1-241, located at the 3' end of the CS-B gene (CS-Benh) stimulates promoter activity specifically in placental trophoblast cells in vitro. Strong activity is exerted by a 23 bp element within the CS-Benh (nts 117-139), shown to interact with transcription enhancer factor (TEF) members of the transcription enhancer activator (TEA) DNA-binding domain-containing family. An identical TEF element is present in the homologous (97.5%) CS-Aenh; however, a few nucleotide differences suppress its activity. Previously, we identified regulatory sequences distinct from the TEF element within an 80 bp modulatory domain (nts 1-80) in the CS-Benh. Using structural and functional assays we now show that CCAAT/enhancer-binding protein (C/EBP) binding sites exist in the 80 bp modulatory domains of both enhancers, and an Elk-1 binding site exists in the modulatory domain of the CS-Aenh. C/EBPα or C/EBPβ strongly repressed CSp.CAT activity but stimulated CSp.CAT.CS-Benh activity. In contrast, the equivalent CS-A enhancer sequences were unable to relieve promoter repression. Elk-1 overexpression also resulted in differential effects on the CS-Aenh versus CS-Benh. Finally, we provide evidence for the association of C/EBPβ with the CS-A and CS-B genes in human placental chromatin, including differential involvement of C/EBPβ with the CS-Aenh versus the CS-Benh, and therefore consistent with the notion that these are regions of regulatory significance in vivo. We conclude that members of the C/EBP and Ets families can differentially modulate CS-Benh and CS-Aenh activity.
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Affiliation(s)
- Aristides Lytras
- Department of Physiology, University of Manitoba, Room 444, 745 Bannatyne Avenue, Winnipeg, Manitoba, Canada.
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Koslowski M, Türeci O, Biesterfeld S, Seitz G, Huber C, Sahin U. Selective activation of trophoblast-specific PLAC1 in breast cancer by CCAAT/enhancer-binding protein beta (C/EBPbeta) isoform 2. J Biol Chem 2009; 284:28607-15. [PMID: 19652226 DOI: 10.1074/jbc.m109.031120] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The trophoblast-specific gene PLAC1 (placenta-specific 1) is ectopically expressed in a wide range of human malignancies, most frequently in breast cancer, and is essentially involved in cancer cell proliferation, migration, and invasion. Here we show that basal activity of the PLAC1 promoter is selectively controlled by ubiquitous transcription factor SP1 and isoform 2 of CCAAT/enhancer-binding protein beta that we found to be selectively expressed in placental tissue and cancer cells. Binding of both factors to their respective elements within the PLAC1 promoter was essential to attain full promoter activity. Estrogen receptor alpha (ERalpha) signaling further augmented transcription and translation of PLAC1 and most likely accounts for the positive correlation between PLAC1 expression levels and the ERalpha status we observed in primary breast cancer specimens. DNA affinity precipitation and chromatin immunoprecipitation assays revealed that transactivation of the PLAC1 promoter by ligand-activated ERalpha is based on a nonclassical pathway independent of estrogen-response elements, by tethering of ERalpha to DNA-bound CCAAT/enhancer-binding protein beta-2, and SP1. Our findings provide first insight into a novel and hitherto unknown regulatory mechanism governing selective activation of trophoblast-specific gene expression in breast cancer.
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Affiliation(s)
- Michael Koslowski
- Department of Internal Medicine III, Experimental and Translational Oncology, Johannes Gutenberg University, 55131 Mainz, Germany
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Aronow BJ, Richardson BD, Handwerger S. Microarray analysis of trophoblast differentiation: gene expression reprogramming in key gene function categories. Physiol Genomics 2001; 6:105-16. [PMID: 11459926 DOI: 10.1152/physiolgenomics.2001.6.2.105] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Placental development results from a highly dynamic differentiation program. We used DNA microarray analysis to characterize the process by which human cytotrophoblast cells differentiate into syncytiotrophoblast cells in a purified cell culture system. Of 6,918 genes analyzed, 141 genes were induced and 256 were downregulated by more than 2-fold. Dynamically regulated genes were divided by the K-means algorithm into 9 kinetic pattern groups, then by biologic classification into 6 overall functional categories: cell and tissue structural dynamics, cell cycle and apoptosis, intercellular communication, metabolism, regulation of gene expression, and expressed sequence tag (EST) and function unknown. Gene expression changes within key functional categories were tightly coupled to morphological changes. In several key gene function categories, such as cell and tissue structure, many gene members of the category were strongly activated while others were strongly repressed. These findings suggest that differentiation is augmented by "categorical reprogramming" in which the function of induced genes is enhanced by preventing the further synthesis of categorically related gene products.
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Affiliation(s)
- B J Aronow
- Departments of Endocrinology and Molecular and Developmental Biology, Children's Hospital Research Foundation, University of Cincinnati College of Medicine, Cincinnati, Ohio 45229-2029, USA
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Schmid B, Wong S, Mitchell BF. Transcriptional regulation of oxytocin receptor by interleukin-1beta and interleukin-6. Endocrinology 2001; 142:1380-5. [PMID: 11250916 DOI: 10.1210/endo.142.4.8107] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The up-regulation of oxytocin (OT) receptors in late pregnancy results principally from increased synthesis of messenger RNA. The 5'-flanking region of the human OT receptor gene contains several putative binding sites for nuclear factor-interleukin-6 (NF-IL6), also known as CAAT/enhancer binding protein-beta. This trans-acting factor modulates the expression of genes involved in acute inflammatory responses. Proinflammatory cytokines, such as IL-1beta or IL-6, have been implicated as mediators in both preterm and term labor, particularly in association with intrauterine infection. We hypothesized that IL-1beta and IL-6 induce OT receptor gene expression in human myometrial cells, and this is mediated by NF-IL6 and cognate response elements in the 5'-flanking region of the OT receptor gene. Contrary to the hypothesis, both IL-1beta and IL-6 treatment resulted in a significant decrease in OT receptor messenger RNA measured by ribonuclease protection analysis. Using electrophoretic mobility shift assay, we have shown that NF-IL6 is present at low levels that appear to be increased after treatment with either IL-1beta or IL-6. Using deletion analysis and functional transfection studies in HeLa cells, we demonstrated that the OT receptor gene promoter displays constitutive basal activity and is negatively regulated by both IL-1beta and IL-6. This suppressive ability of IL-1beta and IL-6 depends on the -1203/-722 region of the OT receptor promoter, which contains binding sites for NF-IL6, acute phase response element, and NF-kappaB. Our findings suggest a role for IL-1beta and IL-6 in the transcriptional regulation of the human OT receptor gene.
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Affiliation(s)
- B Schmid
- Perinatal Research Center, Department of Obstetrics and Gynecology, HMRC 220, University of Alberta, Edmonton, Alberta, Canada T6G 2S2
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Handwerger S, Freemark M. The roles of placental growth hormone and placental lactogen in the regulation of human fetal growth and development. J Pediatr Endocrinol Metab 2000; 13:343-56. [PMID: 10776988 DOI: 10.1515/jpem.2000.13.4.343] [Citation(s) in RCA: 209] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The human growth hormone (hGH)/human placental lactogen (hPL) gene family, which consists of two GH and three PL genes, is important in the regulation of maternal and fetal metabolism and the growth and development of the fetus. During pregnancy, pituitary GH (hGH-N) expression in the mother is suppressed; and hGH-V, a GH variant expressed by the placenta, becomes the predominant GH in the mother. hPL, which is the product of the hPL-A and hPL-B genes, is secreted into both the maternal and fetal circulations after the sixth week of pregnancy. hGH-V and hPL act in concert in the mother to stimulate insulin-like growth factor (IGF) production and modulate intermediary metabolism, resulting in an increase in the availability of glucose and amino acids to the fetus. In the fetus, hPL acts via lactogenic receptors and possibly a unique PL receptor to modulate embryonic development, regulate intermediary metabolism and stimulate the production of IGFs, insulin, adrenocortical hormones and pulmonary surfactant. hGH-N, which is expressed by the fetal pituitary, has little or no physiological actions in the fetus until late in pregnancy due to the lack of functional GH receptors on fetal tissues. hGH-V, which is also a potent somatogenic hormone, is not released into the fetus. Taken together, studies of the hGH/hPL gene family during pregnancy reveal a complex interaction of the hormones with one another and with other growth factors. Additional investigations are necessary to clarify the relative roles of the family members in the regulation of fetal growth and development and the factors that modulate the expression of the genes.
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Affiliation(s)
- S Handwerger
- Department of Pediatrics, University of Cincinnati College of Medicine and Children's Hospital Medical Center, Ohio, USA
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Kanda Y, Richards RG, Handwerger S. Apolipoprotein A-I stimulates human placental lactogen release by activation of MAP kinase. Mol Cell Endocrinol 1998; 143:125-31. [PMID: 9806357 DOI: 10.1016/s0303-7207(98)00125-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Apolipoprotein A-I (apo A-I) stimulates human placental lactogen (hPL) release via protein kinase C (PKC)-dependent pathways. Since PKC has been shown to activate the MAP kinase cascade in other cell types, we examined the effect of two inhibitors of the MAP kinase cascade on apo A-I-induced hPL secretion and the effect of apo A-I on MAP kinase activity in human trophoblast cells. Apigenin (10 microM) and PD98059 (100 microM) inhibited apo A-I-induced hPL release by 94 and 73%, respectively. Moreover, apo A-I activated MAP kinase in a time- and dose-dependent manner. Activation of PKC by phorbol myristate acetate (PMA) stimulated MAP kinase activity, and down-regulation of PKC completely prevented apo A-I-stimulation of MAP kinase activity. Taken together, these results strongly suggest that activation of MAP kinase is involved in the intracellular mechanism of apo A-I-induced hPL release.
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Affiliation(s)
- Y Kanda
- Division of Pediatric Endocrinology, The Children's Hospital Medical Center and the University of Cincinnati College of Medicine, OH 45229, USA
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Orwig KE, Wolfe MW, Cohick CB, Dai G, Peters TJ, Soares MJ. Trophoblast-specific regulation of endocrine-related genes. Placenta 1998. [DOI: 10.1016/s0143-4004(98)80007-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
Through the cloning of two transcription factors named NF-IL6 and STAT3/APRF, two types of IL-6 signal transduction pathways from the cell surface to the nucleus have been revealed. NF-IL6 is phosphorylated and activated by a Ras-dependent MAP kinase cascade, while STAT3/APRF is directly tyrosine-phosphorylated by JAK kinases that associate with the cytoplasmic portion of the receptor, and translocates to the nucleus and activates transcription (JAK-STAT pathway). STAT3 is also tyrosine phosphorylated in response to epidermal growth factor (EGF), granulocyte colony-stimulating factor (G-CSF), leptin and other IL-6-type cytokines including ciliary neurotrophic factor (CNTF), oncostatin M and leukemia inhibitory factor (LIF). Mice deficient in the genes for NF-IL6 and STAT3 were generated. NF-IL6 mice were highly susceptible to facultative intracellular bacteria owing to ineffective killing of the pathogens by the macrophages. Futhermore, the tumor cytotoxicity of macrophages from NF-IL6 KO mice was severely impaired. These results demonstrate a crucial role of NF-IL6 in macrophage bactericidal and tumoricidal activities. The target disruption of STAT3 resulted in embryonic lethality prior to gastrulation, demonstrating that STAT3 is essential for the early development of mouse embryos.
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Affiliation(s)
- S Akira
- Department of Biochemistry, Hyogo College of Medicine, Japan
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Stephanou A, Okosi A, Knight RA, Chowdrey HS, Latchman DS. C/EBP activates the human corticotropin-releasing hormone gene promoter. Mol Cell Endocrinol 1997; 134:41-50. [PMID: 9406848 DOI: 10.1016/s0303-7207(97)00170-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The purpose of these studies was to identify whether transcription factors, associated with cytokine signalling, affected promoter activity of the corticotropin releasing hormone (CRH) gene. Fragments of a 3.6 kb sequence of the human CRH gene promoter were amplified by PCR and ligated upstream of a CAT reporter. These constructs were transfected into a variety of cell lines, either alone or together, with transcription factor expression vectors. Basal activity of a 3070 bp CRH promoter fragment was only seen in neuronal and lymphoblastoid cell lines. Promoter activity was increased by the transcription factors C/EBPbeta (NF-IL6) and more strongly, by C/EBPdelta (NF-IL6beta). Increased CRH promoter activity following phorbol ester treatment was inhibited by a dominant negative NF-IL6 mutant, showing that the effects of phorbol ester were principally mediated by C/EBP. Moreover, the inverse changes in the expression of CRH in the hypothalamus and spleens of arthritic rats were paralleled by similar inverse changes in NF-IL6beta expression in these organs. These data show that some transcription factors associated with cytokine signalling can also activate the CRH promoter.
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Affiliation(s)
- A Stephanou
- Department of Molecular Pathology, University College London, UK
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Toda K, Akira S, Kishimoto T, Sasaki H, Hashimoto K, Yamamoto Y, Sagara Y, Shizuta Y. Identification of a transcriptional regulatory factor for human aromatase cytochrome P450 gene expression as nuclear factor interleukin-6 (NF-IL6), a member of the CCAAT/enhancer-binding protein family. EUROPEAN JOURNAL OF BIOCHEMISTRY 1995; 231:292-9. [PMID: 7635140 DOI: 10.1111/j.1432-1033.1995.tb20699.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Human aromatase cytochrome P450 catalyzes the ultimate reaction in the estrogen biosynthetic pathway by coupling with another enzyme, NADPH-cytochrome P450 reductase, in the endoplasmic reticulum. The expression of the gene encoding the enzyme (CYP19) is regulated, in part, by tissue-specific promoters through the use of alternative-splicing mechanisms. Recently, we have localized a transcriptional activating element at positions -2141 to -2115 relative to the major cap site of the gene, by transient expression analyses in human BeWo choriocarcinoma cells using the bacterial chloramphenicol acetytransferase reporter gene ligated with CYP19 promoter sequences which regulate expression in this tissue. Here, we report the isolation of a cDNA encoding a DNA-binding protein which binds specifically to the regulatory element. The deduced amino-acid sequence of the insert is identical to that corresponding to the DNA-binding domain and the dimerization domain of a transcription factor, nuclear factor interleukin-6 (NF-IL6), a member of the CCAAT/enhancer-binding protein (C/EBP) family. Studies using specific antibodies against members of the C/EBP family demonstrate that NF-IL6 is the major nuclear factor binding to the regulatory element in BeWo cells; nevertheless. C/EBP alpha also seems to be involved. Disruption of the NF-IL6-binding site within the regulatory element resulted in the disappearance of the transcriptional enhancing activity of the element, indicating that NF-IL6 is at least one of the nuclear factor(s) which enhances transcription through binding to the cis-acting element. These results indicate the intrinsic importance of NF-IL6 in the transcriptional regulation of CYP19 expression.
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Affiliation(s)
- K Toda
- Department of Medical Chemistry, Kochi Medical School, Japan
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