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Duan R, Liu Y, Xue H, Yang M, Cheng G. Cross-Sectional Association between Overall Diet Quality and Body Composition among Children and Adolescents in South China. J Acad Nutr Diet 2014. [DOI: 10.1016/j.jand.2014.06.344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Su XH, Duan R, Sun YY, Wen JF, Kang DG, Lee HS, Cho KW, Jin SN. Cardiovascular effects of ethanol extract of Rubus chingii Hu (Rosaceae) in rats: an in vivo and in vitro approach. JOURNAL OF PHYSIOLOGY AND PHARMACOLOGY : AN OFFICIAL JOURNAL OF THE POLISH PHYSIOLOGICAL SOCIETY 2014; 65:417-424. [PMID: 24930514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Accepted: 03/25/2014] [Indexed: 06/03/2023]
Abstract
Rubus chingii Hu (Rosaceae) is an important traditional Chinese medicine that has been used to improve function of the kidney and treat excessive polyuria. However, the effects of Rubus chingii on the cardiovascular system and its pharmacological mechanisms of action have not been studied. The aim of the present study was to evaluate the cardiovascular effects of ethanol extract of Rubus chingii (ERC) in rats. The changes in systolic blood pressure and heart rate of rats and vascular tone of aortic rings in in vitro were measured using pressure transducer and force transducer, respectively, connected to a multichannel recording system. ERC decreased systolic blood pressure and heart rate in a concentration-dependent manner. ERC induced vasorelaxation in a concentration-dependent manner. The ERC-induced vasorelaxation was not observed in the absence of the endothelium. The vasorelaxant effect of ERC was significantly attenuated by inhibition of endothelial NO synthase (eNOS), soluble guanylyl cyclase (sGC), or Ca(2+) entry from extracellular sources with L-NAME, ODQ, diltiazem, or extracellular Ca(2+) depletion, respectively. Similarly, an inhibition of Akt with wortmannin attenuated the ERC-induced vasorelaxation. Modulators of the store-operated Ca(2+) entry, thapsigargin, Gd(3+), and 2-aminoethyl diphenylborinate markedly attenuated the ERC-induced vasorelaxation. Furthermore, 4-aminopyridine an inhibitor of voltage-dependent K(+) (KV) channel, significantly attenuated the ERC-induced vasorelaxation. However, tetraethylammonium and glibenclamide, had no significant effect on the ERC-induced vasorelaxation. Indomethacin, atropine, and propranolol had no effects on the ERC-induced vasorelaxation. The present study demonstrates that ERC induces vasorelaxation via endothelium-dependent two-step signaling: an activation of the Ca(2+)-eNOS-NO signaling in the endothelial cells and then subsequent stimulation of the NO-sGC-cGMP-KV channel signaling in the vascular smooth muscle cells. The Akt-eNOS pathway is also suggested to be involved in this relaxation. Also, the findings suggest that the ERC-induced vasorelaxation is closely related to the hypotensive action of the agent.
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Luo S, Huang W, Chen C, Pan Q, Duan R, Wu L. A novel deletion to normal size in the sperm of a fragile X full mutation male. Clin Genet 2013; 86:295-7. [PMID: 24635531 DOI: 10.1111/cge.12287] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 09/21/2013] [Accepted: 09/23/2013] [Indexed: 11/30/2022]
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Khosropour CM, Duan R, Metsch LR, Feaster DJ, Golden MR. O02.4 Persistent/Recurrent Chlamydial Infection Among STD Clinic Patients Treated with CDC-Recommended Therapies. Sex Transm Infect 2013. [DOI: 10.1136/sextrans-2013-051184.0092] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Ke J, Duan R. Effects of flavonoids from semen cuscutae on the hippocampal-hypothalamic-pituitary-ovarian sex hormone receptors in female rats exposed to psychological stress. CLIN EXP OBSTET GYN 2013; 40:271-274. [PMID: 23971257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
OBJECTIVE To investigate the effects of flavonoids from semen cuscutae (FSCs) on the hippocampal-hypothalamic-pituitary-ovarian sex hormone receptors in female rats exposed to psychological stress and to explore the related mechanism. MATERIALS AND METHODS Flavonoids were obtained from semen cuscutae using solvent extraction and polyamide column chromatography. Sound, light, and electricity were combined into psychological stress for endocrine dysfunction model establishment in female rats. The effects of FSCs on estrogen receptor (ER) in the hippocampus, hypothalamus, and pituitaries, as well as on follicle-stimulating hormone receptor (FSHR) and luteinizing hormone receptor (LHR) in the ovaries of the psychologically stressed rats were quantitatively analyzed using immunohistochemistry and image analysis. RESULTS FSCs increased ER expression in the hippocampus, hypothalamus, and pituitaries, as well as LHR expression in the ovaries, but had no effect on FSHR expression in the ovaries. CONCLUSION FSCs are an effective medicine in the treatment of ovarian endocrine dysfunction in psychologically stressed rats.
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Su SM, Zeng XB, Li LF, Duan R, Bai LY, Li AG, Wang J, Jiang S. Arsenate reduction and methylation in the cells of Trichoderma asperellum SM-12F1, Penicillium janthinellum SM-12F4, and Fusarium oxysporum CZ-8F1 investigated with X-ray absorption near edge structure. JOURNAL OF HAZARDOUS MATERIALS 2012; 243:364-7. [PMID: 23122191 DOI: 10.1016/j.jhazmat.2012.09.061] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 09/12/2012] [Accepted: 09/26/2012] [Indexed: 05/26/2023]
Abstract
Synchrotron radiation-based X-ray absorption near edge structure (XANES) was introduced to directly analysis chemical species of arsenic (As) in the cells of Trichoderma asperellum SM-12F1, Penicillium janthinellum SM-12F4, and Fusarium oxysporum CZ-8F1 capable of As accumulation and volatilisation. After exposure to As(V) of 500 mg L(-1) for 15 days, a total of 60.5% and 65.3% of the accumulated As in the cells of T. asperellum SM-12F1 and P. janthinellum SM-12F4, respectively, was As(III), followed by 31.3% and 32.4% DMA (dimethylarsinic acid), 8.3% and 2.3% MMA (monomethylarsonic acid), respectively. However, for F. oxysporum CZ-8F1, 54.5% of the accumulated As was As(III), followed by 37.8% MMA and 7.7% As(V). The reduction and methylation of As(V) formed As(III), MMA, and DMA as the primacy products, and the reduction of As(V) might be more easily processed than the methylation. These results will help to understanding the mechanisms of As detoxification and its future application in bioremediation.
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Zheng KYZ, Choi RCY, Cheung AWH, Guo AJY, Bi CWC, Zhu KY, Fu Q, Du Y, Zhang WL, Zhan JYX, Duan R, Lau DTW, Dong TTX, Tsim KWK. Flavonoids from Radix Astragali induce the expression of erythropoietin in cultured cells: a signaling mediated via the accumulation of hypoxia-inducible factor-1α. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:1697-1704. [PMID: 21309574 DOI: 10.1021/jf104018u] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Radix Astragali (RA) is commonly used as a health food supplement to reinforce the body vital energy. Flavonoids, including formononetin, ononin, calycosin, and calycosin-7-O-β-d-glucoside, are considered to be the major active ingredients within RA. Here, we provided different lines of evidence that the RA flavonoids stimulated the expression of erythropoietin (EPO), the central regulator of red blood cell mass, in cultured human embryonic kidney fibroblasts (HEK293T). A plasmid containing hypoxia response element (HRE), a critical regulator for EPO transcription, was tagged upstream of a firefly luciferase gene, namely, pHRE-Luc, which was being transfected into fibroblasts. The application of RA flavonoids onto the transfected cells induced the transcriptional activity of HRE. To account for the transcriptional activation after the treatment of flavonoids, the expression of hypoxia-inducible factor-1α (HIF-1α) was markedly increased: The increase was in both mRNA and protein levels. In addition, the degradation of HIF-1α was reduced under the effect of flavonoids. The regulation of HIF-1α therefore could account for the activation of EPO expression mediated by the RA flavonoids. The current results therefore reveal the function of this herb in enhancing hematopoietic functions.
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Li W, Duan R, Kooy F, Sherman SL, Zhou W, Jin P. Germline mutation of microRNA-125a is associated with breast cancer. J Med Genet 2009; 46:358-60. [PMID: 19411564 DOI: 10.1136/jmg.2008.063123] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
MicroRNAs (miRNAs) are small non-coding RNAs that inhibit expression of specific target genes at the posttranscriptional level. MiRNAs are often found to be misregulated in human cancer, and they can act as either potent oncogenes or tumour suppressor genes. Here we show that a germline mutation in mature miR-125a is highly associated with breast cancer tumorigenesis, suggesting that miR-125a is likely to function as a tumour suppressor gene in human cancer.
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Erlanson-Albertsson C, Duan R, Rippe C, Berger K. Influence of diabetes on intestinal fat digestion. Exp Clin Endocrinol Diabetes 2009. [DOI: 10.1055/s-0029-1211874] [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: 10/20/2022]
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Jones JE, Wang L, Kropf PL, Duan R, Johnson DE. Src family kinase gene targets during myeloid differentiation: identification of the EGR-1 gene as a direct target. Leukemia 2009; 23:1933-5. [PMID: 19494839 DOI: 10.1038/leu.2009.118] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Baum MK, Rafie C, Sales S, Lai S, Duan R, Jayaweera DT, Page JB, Campa A. C-reactive protein: a poor marker of cardiovascular disease risk in HIV+ populations with a high prevalence of elevated serum transaminases. Int J STD AIDS 2008; 19:410-3. [PMID: 18595880 DOI: 10.1258/ijsa.2007.007207] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Blood lipids and high-sensitivity C-reactive protein (hsCRP) are used to assess cardiovascular disease (CVD) risk. We evaluated in a cross-sectional design the relationship of hsCRP to markers of liver function (aspartate and alanine transaminases [AST and ALT, respectively]), CVD risk factors and HIV-disease progression markers in 226 HIV-1 sero-positive drug users. hsCRP showed a significant inverse relationship with ALT and high-density lipoprotein, independent of age, gender, viral load, CD4 cell-count and antiretroviral (ARV) use, and was not significantly associated with HIV-disease progression markers. Serum markers of liver damage, AST and ALT, were associated with lower hsCRP, total cholesterol, low-density lipoproteins and triglycerides. Elevated liver enzymes (> or =40 IU/L) were predictive of hsCRP levels that are considered a low risk for CVD. In conclusion, hsCRP may not be a reliable marker of CVD risk in populations with HIV at-risk for elevated liver enzymes due to high hepatitis B virus/hepatitis C virus prevalence and ARV use.
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Duan R, van Dun JM, Remeijer L, Siemerink M, Mulder PGH, Norberg P, Osterhaus ADME, Verjans GMGM. Prevalence of herpes simplex virus type 1 glycoprotein G (gG) and gI genotypes in patients with herpetic keratitis. Br J Ophthalmol 2008; 92:1195-200. [PMID: 18617539 DOI: 10.1136/bjo.2007.136044] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIM Recent phylogenetic analyses on the herpes simplex virus type 1 (HSV-1) genes US4, encoding glycoprotein G (gG) and US7, encoding gI, of clinical HSV-1 isolates have led to the classification of HSV-1 into three genotypes, arbitrarily designated as A, B and C. The prevalence of the HSV-1 gG and gI genotypes and their potential disease association was determined in a large cohort of patients with herpetic keratitis (HK). METHODS Primary corneal HSV-1 isolates of 178 HK patients were genotyped by a PCR-based restriction fragment length polymorphism method targeting the viral genes US4 and US7. RESULTS Genotype B was more frequently expressed by the corneal HSV-1 isolates compared with genotypes A and C. Fifty-five of 178 corneal isolates (31%) had different genotypes in both loci. No clinically relevant associations were observed between the HSV-1 genotypes and disease outcome in the HK patients studied. CONCLUSIONS The data presented demonstrate a high frequency of recombinant corneal HSV-1 isolates and suggest that clinical outcome of HSV-1-induced keratitis is independent of a gG or gI genotype.
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Miranda MB, Duan R, Thomas SM, Grandis JR, Redner RL, Jones JE, Johnson DE. Gefitinib potentiates myeloid cell differentiation by ATRA. Leukemia 2008; 22:1624-7. [PMID: 18305561 DOI: 10.1038/leu.2008.28] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Yarilin D, Duan R, Huang YM, Xiao BG. Dendritic cells exposed in vitro to TGF-beta1 ameliorate experimental autoimmune myasthenia gravis. Clin Exp Immunol 2002; 127:214-9. [PMID: 11876742 PMCID: PMC1906332 DOI: 10.1046/j.1365-2249.2002.01748.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Experimental autoimmune myasthenia gravis (EAMG) is an animal model for human myasthenia gravis (MG), characterized by an autoaggressive T-cell-dependent antibody-mediated immune response directed against the acetylcholine receptor (AChR) of the neuromuscular junction. Dendritic cells (DC) are unique antigen-presenting cells which control T- and B-cell functions and induce immunity or tolerance. Here, we demonstrate that DC exposed to TGF-beta1 in vitro mediate protection against EAMG. Freshly prepared DC from spleen of healthy rats were exposed to TGF-beta1 in vitro for 48 h, and administered subcutaneously to Lewis rats (2 x 10(6)DC/rat) on day 5 post immunization with AChR in Freund's complete adjuvant. Control EAMG rats were injected in parallel with untreated DC (naive DC) or PBS. Lewis rats receiving TGF-beta1-exposed DC developed very mild symptoms of EAMG without loss of body weight compared with control EAMG rats receiving naive DC or PBS. This effect of TGF-beta1-exposed DC was associated with augmented spontaneous and AChR-induced proliferation, IFN-gamma and NO production, and decreased levels of anti-AChR antibody-secreting cells. Autologous DC exposed in vitro to TGF-beta1 could represent a new opportunity for DC-based immunotherapy of antibody-mediated autoimmune diseases.
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Wankell M, Kaesler S, Zhang YQ, Florence C, Werner S, Duan R. The activin binding proteins follistatin and follistatin-related protein are differentially regulated in vitro and during cutaneous wound repair. J Endocrinol 2001; 171:385-95. [PMID: 11739004 DOI: 10.1677/joe.0.1710385] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Follistatin is a secreted protein that binds activin in vitro and in vivo and thereby inhibits its biological functions. Recently, related human and murine genes, designated follistatin-related gene (FLRG), were identified, and their products were shown to bind activin with high affinity. In this study we further characterized the murine FLRG protein, and we analyzed its tissue-specific expression and regulation in comparison with those of follistatin. Transient expression of the mouse FLRG protein in COS-1 cells revealed that the FLRG cDNA encodes a secreted glycoprotein. FLRG mRNA was expressed at high levels in the lung, the testis, the uterus and, particularly, the skin. Immunohistochemistry revealed the presence of FLRG in the basement membrane between the dermis and the epidermis and around blood vessels. FLRG mRNA expression was induced in keratinocytes by keratinocyte growth factor, epidermal growth factor and transforming growth factor-beta 1, and in fibroblasts by platelet-derived growth factor and epidermal growth factor. The induction was more rapid, but weaker, than that of follistatin. Most interestingly, both follistatin and FLRG were expressed during the wound healing process, but their distribution within the wound was different. The different expression pattern of FLRG and follistatin and their differential regulation suggest different functions of these activin-binding proteins in vivo.
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Duan R, Liu TC, Li Y, Guo H, Yao LB. Signal transduction pathways involved in low intensity He-Ne laser-induced respiratory burst in bovine neutrophils: a potential mechanism of low intensity laser biostimulation. Lasers Surg Med 2001; 29:174-8. [PMID: 11553907 DOI: 10.1002/lsm.1106] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND AND OBJECTIVE Low intensity He-Ne laser irradiation has been reported to induce respiratory burst of neutrophils for a long time, but the mechanism remains obscure. We speculated that it is mediated by some signal transduction pathways. STUDY DESIGN/MATERIALS AND METHODS The protein tyrosine kinases (PTKs) inhibitor, genistein, the phospholipase C (PLC) inhibitor, U-73122, and the protein kinase C (PKC) inhibitor, calphostin C, were used to probe signal transduction pathways of respiratory burst of bovine neutrophils which were induced by He-Ne laser at a dose of 300 J/m(2), respectively. RESULTS The inhibitor of PTKs can completely inhibit the He-Ne laser-induced respiratory burst of neutrophils. PLC and PKC inhibitors can obviously reduce it, but not fully inhibit it. CONCLUSION These results suggest that PTKs play a key role in the He-Ne laser-induced respiratory burst of neutrophils and [PTK-PLC-PKC-NADPH oxidase] signal transduction pathways may be involved in this process.
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Connolly K, Cho YH, Duan R, Fikes J, Gregorio T, LaFleur DW, Okoye Z, Salcedo TW, Santiago G, Ullrich S, Wei P, Windle K, Wong E, Yao XT, Zhang YQ, Zheng G, Moore PA. In vivo inhibition of Fas ligand-mediated killing by TR6, a Fas ligand decoy receptor. J Pharmacol Exp Ther 2001; 298:25-33. [PMID: 11408521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023] Open
Abstract
TR6, a member of the tumor necrosis factor (TNF) receptor superfamily, has recently been shown to bind to Fas ligand (FasL) and inhibit FasL-mediated cell killing in vitro. In the current study, we demonstrate that TR6 can block the lethal activity of FasL in multiple in vitro systems, and extend this finding to an in vivo model of hepatitis. The binding of human TR6 to human FasL was verified with BIAcore chip technology. Human primary hepatocytes, HT-29 cells and Jurkat cells were assayed for viability to demonstrate TR6 inhibition of FasL-mediated cytotoxicity in vitro. Human TR6 was also shown to cross-react with membrane-bound mouse FasL, since the in vitro cytotoxic activity of L929 cells transfected with murine FasL was inhibited in the presence of human TR6. In vivo, FasL-induced acute, lethal, fulminant hepatic apoptosis resulting in death within 2 h of intravenous injection into Fas+ mice, but not Fas- MRL/lpr mice. Pretreatment of mice with TR6 blocked FasL-induced mortality, presumably by attenuating FasL-induced hepatic apoptosis. Thus, in both in vitro and in vivo systems, TR6 acts as a functional FasL decoy receptor and may be clinically useful in the treatment of hepatitis and other diseases associated with FasL-mediated tissue injury.
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Xie W, Duan R, Safe S. Activation of adenosine deaminase in MCF-7 cells through IGF-estrogen receptor alpha crosstalk. J Mol Endocrinol 2001; 26:217-28. [PMID: 11357058 DOI: 10.1677/jme.0.0260217] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Adenosine deaminase (ADA) regulates cellular levels of adenosine and deoxyadenosine, and 17beta-estradiol (E(2)) induces ADA mRNA in MCF-7 human breast cancer cells. IGF-I also induces ADA gene expression in these cells, and induction of this response through IGF activation of estrogen receptor alpha (ERalpha) was further investigated. IGF and other polypeptide growth factors induce reporter gene expression in MCF-7 cells cotransfected with ERalpha expression plasmid and pADA211, a construct containing the -211 to +11 region of the ADA gene promoter which is required for high basal and E(2)-inducible activity. Deletion analysis of this promoter demonstrates that IGF activates ERalpha/Sp1 interactions with multiple GC-rich sites in the promoter and this response is abrogated in cells transfected with ERalpha containing mutations at Ser(118) or Ser(163). IGF induces both MAPK (mitogen-activated protein kinase) and PI3-K (phosphatidylinositol-3-kinase) phosphorylation cascades in MCF-7 cells; however, using a series of inhibitors and dominant negative constructs, our results show that induction of ADA by IGF activation of ERalpha/Sp1 is dependent on the MAPK signaling pathway.
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Duan R, Xie W, Burghardt RC, Safe S. Estrogen receptor-mediated activation of the serum response element in MCF-7 cells through MAPK-dependent phosphorylation of Elk-1. J Biol Chem 2001; 276:11590-8. [PMID: 11145955 DOI: 10.1074/jbc.m005492200] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
17beta-Estradiol (E2) induces c-fos protooncogene expression in MCF-7 human breast cancer cells, and deletion analysis of the c-fos promoter showed that the serum response element (SRE) at -325 to -296 was E2-responsive. The mechanism of ligand-activated estrogen receptor alpha (ERalpha)-dependent activation of gene expression through the SRE was determined by mutational analysis of the promoter, analysis of mitogen-activated protein kinase (MAPK) pathway activation by E2, and transforming growth factor alpha (TGF-alpha) as a positive control. In addition, ERalpha-negative MDA-MB-231 breast cancer and Chinese hamster ovary cells were used as reference cell lines. The results showed that transcriptional activation of the SRE by E2 was due to ERalpha activation of the MAPK pathway and increased binding of the serum response factor and Elk-1 to the SRE. Subsequent studies with dominant negative Elk-1, wild type, and variant GAL4-Elk-1 fusion proteins confirmed that phosphorylation of Elk-1 at serines 383 and 389 in the C-terminal region of Elk-1 is an important downstream target associated with activation of an SRE by E2. Both E2 (ERalpha-dependent) and growth factors (ERalpha-independent) activated the SRE in breast cancer cells via the Ras/MAPK pathway; however, in ER-negative CHO cells that do not express a receptor for TGF-alpha, only hormone-induced activation was observed in cells transfected with ERalpha.
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Porter W, Wang F, Duan R, Qin C, Castro-Rivera E, Kim K, Safe S. Transcriptional activation of heat shock protein 27 gene expression by 17beta-estradiol and modulation by antiestrogens and aryl hydrocarbon receptor agonists. J Mol Endocrinol 2001; 26:31-42. [PMID: 11174852 DOI: 10.1677/jme.0.0260031] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Heat shock protein 27 (Hsp 27) is expressed in mammary tumors and may play a role in tumor growth and response to anti-neoplastic drug therapy. 17beta-Estradiol (E2) induces Hsp 27 mRNA levels in MCF-7 human breast cancer cells, and we have investigated the comparative inhibitory mechanisms using the aryl hydrocarbon receptor (AhR) agonist, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and the direct-acting antiestrogen ICI 164,384. TCDD inhibited E2-induced Hsp 27 gene expression and analysis of the Hsp 27 gene promoter showed that the inhibitory response was associated with AhR interactions with a pentanucleotide motif at -3 to +2 in the promoter that corresponded to the core sequence of a dioxin responsive element. In contrast, ICI 164,384 induced Hsp 27 gene expression and reporter gene activity in MCF-7 cells and this represents one of the few examples of the estrogen receptor-alpha (ERalpha) agonist activity of the 'pure' antiestrogen ICI 164,384.
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Xie W, Duan R, Chen I, Samudio I, Safe S. Transcriptional activation of thymidylate synthase by 17beta-estradiol in MCF-7 human breast cancer cells. Endocrinology 2000; 141:2439-49. [PMID: 10875244 DOI: 10.1210/endo.141.7.7538] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Thymidylate synthase (TS) catalyzes methylation of deoxyuridine phosphate to give deoxythymidine phosphate, and 17beta-estradiol (E2) induces TS gene expression in MCF-7 human breast cancer cells. Analysis of the TS gene promoter showed that E2-responsiveness required the -229 to -140 promoter region containing a G-rich sequence and CACCC box. Subsequent mutational analysis of this region indicated that only the G-rich motif (-150 to -142) was required for E2 action. Results of gel mobility shift and in vitro DNA footprinting assays showed that both estrogen receptor alpha (ERalpha) and Sp1 proteins were required for hormone-induced trans-activation that involved ERalpha/Sp1 binding to the G-rich site in which only Sp1 protein bound DNA. Both proteins also interacted in Drosophila cells in functional assays, confirming the transcriptional activation of TS-involved ERalpha/Sp1, and this adds to the increasing number of genes that are activated through this pathway in breast cancer cells.
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Wang F, Duan R, Chirgwin J, Safe SH. Transcriptional activation of cathepsin D gene expression by growth factors. J Mol Endocrinol 2000; 24:193-202. [PMID: 10750020 DOI: 10.1677/jme.0.0240193] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Insulin-like growth factor-I (IGF-I), transforming growth factor alpha (TGFalpha) and epidermal growth factor (EGF) induced cathepsin D gene expression and reporter gene activity in MCF-7 human breast cancer cells transiently transfected with a construct (pCD1) containing a -2576 to -124 cathepsin D gene promoter insert. In contrast, IGF-I, but not TGFalpha or EGF, induced reporter gene activity in cells cotransfected with wild-type estrogen receptor (ER) expression plasmid and a construct (pCD2) containing estrogen-responsive downstream elements from -208 to -101. Promoter deletion and mutational analysis experiments identified four GC-rich sites and an imperfect palindromic estrogen responsive element required for IGF-I activation of the ER (ligand-independent). Subsequent studies with the mitogen-activated protein kinase (MAPK) inhibitor, PD98059, and a serine(118(-ER mutant confirmed the role of the MAPK pathway for IGF-I activation of the ER in MCF-7 cells. Thus, growth factor activation of ER can mediate transactivation vs ER/Sp1 binding to GC-rich sites and represents a novel pathway for ligand-independent ER action. The divergent pathways for IGF-I and TGFalpha/EGF activation of the ER observed in MCF-7 cells contrast with previous data indicating that pathways for growth factor activation of the ER are dependent on the gene and/or gene promoter and on cell context.
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Duan R, Porter W, Samudio I, Vyhlidal C, Kladde M, Safe S. Transcriptional activation of c-fos protooncogene by 17beta-estradiol: mechanism of aryl hydrocarbon receptor-mediated inhibition. Mol Endocrinol 1999; 13:1511-21. [PMID: 10478842 DOI: 10.1210/mend.13.9.0338] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
17Beta-estradiol (E2) induced c-fos protooncogene mRNA levels in MCF-7 human breast cancer cells, and maximal induction was observed within 1 h after treatment. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) inhibited the E2-induced response within 2 h. The molecular mechanism of this response was further investigated using pFC2-CAT, a construct containing a -1400 to +41 sequence from the human c-fos protooncogene linked to a bacterial chloramphenicol acetyltransferase (CAT) reporter gene. In MCF-7 cells transiently transfected with pFC2-CAT, 10 nM E2 induced an 8.5-fold increase of CAT activity, and cotreatment with 10 nM TCDD decreased this response by more than 45%. Alpha-Naphthoflavone, an aryl hydrocarbon receptor (AhR) antagonist, blocked the inhibitory effects of TCDD; moreover, the inhibitory response was not observed in variant Ah-nonresponsive MCF-7 cells, suggesting that the AhR complex was required for estrogen receptor cross-talk. The E2-responsive sequence (-1220 to -1155) in the c-fos gene promoter contains two putative core pentanucleotide dioxin-responsive elements (DREs) at -1206 to -1202 and -1163 to -1159. In transient transfection assays using wild-type and core DRE mutant constructs, the downstream core DRE (at -1163 to -1159) was identified as a functional inhibitory DRE. The results of photo-induced cross-linking, gel mobility shift, and in vitro DNA footprinting assays showed that the AhR complex interacted with the core DRE that also overlapped the E2-responsive GC-rich site (-1168 to -1161), suggesting that the mechanism for AhR-mediated inhibitory effects may be due to quenching or masking at the Sp1-binding site.
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Duan R. Transcriptional Activation of c-fos Protooncogene by 17 -Estradiol: Mechanism of Aryl Hydrocarbon Receptor-Mediated Inhibition. Mol Endocrinol 1999. [DOI: 10.1210/me.13.9.1511] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Zhao L, Wei JH, Yan GD, Chen WJ, Duan R, Ren W. [Effect of extremely low frequency magnetic field on brain response to selective mental arithmetic under simulated weightlessness]. HANG TIAN YI XUE YU YI XUE GONG CHENG = SPACE MEDICINE & MEDICAL ENGINEERING 1999; 12:161-4. [PMID: 11766706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Objective. To study effects of extremely low frequency magnetic field (ELMF) on brain function state during weightlessness. Method. The brain event-related potentials (ERPs) during a selective mental arithmetic task were compared in 40 normal subjects (20-25 yrs) before and after ELMF (5 Hz) stimulation during simulated weightlessness (head down tilt -10 degrees, HDT). Result. The amplitude of slow positive potentials which were supposed to be related to the mental arithmetic activity decreased significantly especially in 100 min after HDT, but it did not decrease significantly after ELMF stimulation. Conclusion. ELMF stimulation may improve the brain function state during simulated weightlessness.
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