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1.
Eur J Radiol ; 167: 111027, 2023 Oct.
Article in English | MEDLINE | ID: mdl-37634441

ABSTRACT

PURPOSE: To validate MRI Analyzer Quality Control (MA-QC), a free and open-source online software designed to facilitate MR data acquisition quality control and PI-QUAL score calculation. MATERIAL AND METHODS: MA-QC is a web-based software, designed for analysing DICOM data related to MR acquisition parameters. The software allows automatic extraction of 18 technical criteria, and manual input of 12 visual criteria, to calculate the PI-QUAL score. We collected 100 prostate MRI datasets from four MR device manufacturers to test data compatibility, automatic sequence recognition, and robustness of technical criteria extraction from DICOM data. The main issue was to determine the spatial resolution in the phase and frequency directions, due to variable encoding of the DICOM datasets. RESULTS: Acquisition data could be extracted from all sample examinations (100%), with a median analysis speed of 15.2 ± 4.4 images per second and mean processing time of 96 [11-326] seconds per examination. MA-CQ automatically detected the optimal T2-w, DWI and DCE sequences in 71 out of 100 (71%) cases, and required manual selection of at least one sequence in 29 out of 100 (29%) cases to get the best parameters. Display of technical criteria for the 3 sequences was instantaneous. PI-QUAL score could be calculated in all cases. CONCLUSION: This software brings substantial help in the quality assessment of prostate MRI examinations, by providing fast extraction of series data and the 18 technical parameters of PI-QUAL. PI-QUAL scoring can be performed in less than two minutes, helping to focus on the visual criteria, allowing use of this software in the clinical workflow in the aim of improving overall image quality in prostate MR imaging.


Subject(s)
Prostate , Prostatic Neoplasms , Male , Humans , Prostate/diagnostic imaging , Prostatic Neoplasms/diagnostic imaging , Magnetic Resonance Imaging/methods , Software , Quality Control , Retrospective Studies
2.
Andrology ; 7(3): 281-287, 2019 05.
Article in English | MEDLINE | ID: mdl-30734539

ABSTRACT

BACKGROUND: The use of testicular over ejaculated spermatozoa for ICSI has been presented as an alternative to overcome infertility in men with poor semen parameters or high levels of sperm DNA fragmentation. OBJECTIVE: To evaluate the efficacy of testicular ICSI outcomes in couples with no previous live birth and recurrent ICSI failure using ejaculated spermatozoa by comparison to the outcomes of couples with similar history of recurrent ICSI using ejaculated spermatozoa only. MATERIALS AND METHODS: A total of 145 couples undergoing ejaculated or testicular ICSI cycles with no previous live births and with at least two previous failed ICSI cycles with ejaculated spermatozoa were evaluated retrospectively. ICSI was performed either with ejaculated (E-ICSI) or with testicular (T-ICSI) spermatozoa. Semen parameters and sperm DNA quality were assessed prior to the oocyte collection day. Primary outcomes included cumulative live birth and pregnancy rates. Secondary analysis included percentage of DNA fragmentation in ejaculated spermatozoa (SCSA® and TUNEL). RESULTS: Patients undergoing T-ICSI (n = 77) had a significantly higher clinical pregnancy rate/fresh embryo transfer (ET) (27.9%; 17/61) and cumulative live birth rate (23.4%; 15/64) compared to patients using E-ICSI (n = 68) (clinical pregnancy rate/fresh ET: 10%; 6/60 and cumulative live birth rate: 11.4%; 7/61). Further, T-ICSI yield significantly better cumulative live birth rates than E-ICSI for men with high TUNEL (≥36%) (T-ICSI: 20%; 3/15 vs. E-ICSI: 0%; 0/7, p < 0.025), high SCSA® (≥25%) scores (T-ICSI: 21.7%; 5/23 vs. E-ICSI: 9.1%; 1/11, p < 0.01), or abnormal semen parameters (T-ICSI: 28%; 7/25 vs. E-ICSI: 6.7%; 1/15, p < 0.01). CONCLUSIONS: The use of testicular spermatozoa for ICSI in non-azoospermic couples with no previous live births, recurrent ICSI failure, and high sperm DNA fragmentation yields significantly better live birth outcomes than a separate cohort of couples with similar history of ICSI failure entering a new ICSI cycle with ejaculated spermatozoa.


Subject(s)
Sperm Injections, Intracytoplasmic , Spermatozoa , Testis/cytology , Adult , DNA Fragmentation , Ejaculation , Female , Humans , Infertility, Male , Male , Pregnancy , Pregnancy Outcome , Retrospective Studies , Treatment Outcome
3.
Oncogene ; 35(6): 670, 2016 02 11.
Article in English | MEDLINE | ID: mdl-32667144

ABSTRACT

At the request of the University of Luxembourg and following an external investigation, the Editor and Publisher have agreed to retract this paper owing to unreliable data.

5.
Oncogene ; 34(17): 2261-71, 2015 Apr 23.
Article in English | MEDLINE | ID: mdl-24931170

ABSTRACT

The molecular basis for the resistance of tumor cells to cell-mediated cytotoxicity remains poorly understood and thus poses a major challenge for cancer immunotherapy. The present study was designed to determine whether the WNT1-inducible signaling pathway protein 2 (WISP2, also referred to as CCN5), a key regulator of tumor cell plasticity, interferes with tumor susceptibility to cytotoxic T-lymphocyte (CTL)-mediated lysis. We found that silencing WISP2 signaling in human breast adenocarcinoma MCF7 cells impairs CTL-mediated cell killing by a mechanism involving stem cell marker Kruppel-like factor-4 (KLF-4) induction and microRNA-7 (miR-7) downregulation. Inhibition of transforming growth factor beta (TGF-ß) signaling using the A83-01 inhibitor in MCF7-shWISP2 cells resulted in a significant reversal of the epithelial-to-mesenchymal-transitioned (EMT) phenotype, the expression of KLF-4 and a partial recovery of target susceptibility to CTLs. More importantly, we showed that silencing KLF-4 was accompanied by a reduction in MCF7-shWISP2 resistance to CTLs. Using human breast cancer tissues, we demonstrated the coexpression of KLF-4 with EMT markers and TGF-ß pathway signaling components. More importantly, we found that KLF-4 expression was accompanied by miR-7 inhibition, which is partly responsible for impairing CTL-mediated lysis. Thus, our data indicate that WISP2 has a role in regulating tumor cell susceptibility through EMT by inducing the TGF-ß signaling pathway, KLF-4 expression and miR-7 inhibition. These studies indicate for the first time that WISP2 acts as an activator of CTL-induced killing and suggests that the loss of its function promotes evasion of immunosurveillance and the ensuing progression of the tumor.


Subject(s)
Breast Neoplasms/immunology , CCN Intercellular Signaling Proteins/immunology , Gene Expression Regulation, Neoplastic/immunology , Immunity, Cellular , Kruppel-Like Transcription Factors/immunology , MicroRNAs/immunology , RNA, Neoplasm/immunology , Repressor Proteins/immunology , T-Lymphocytes/immunology , Breast Neoplasms/pathology , CCN Intercellular Signaling Proteins/genetics , Cell Line, Tumor , Female , Humans , Kruppel-Like Factor 4 , Kruppel-Like Transcription Factors/genetics , MicroRNAs/genetics , Neoplasm Proteins/genetics , Neoplasm Proteins/immunology , RNA, Neoplasm/genetics , Repressor Proteins/genetics , T-Lymphocytes/pathology , Wnt Signaling Pathway
6.
Oncogene ; 29(31): 4436-48, 2010 08 05.
Article in English | MEDLINE | ID: mdl-20543867

ABSTRACT

Epithelial to mesenchymal transition (EMT) is a key step toward metastasis. MCF7 breast cancer cells conditionally expressing the EMT master regulator SNAI1 were used to identify early expressed microRNAs (miRNAs) and their targets that may contribute to the EMT process. Potential targets of miRNAs were identified by matching lists of in silico predicted targets and of inversely expressed mRNAs. MiRNAs were ranked based on the number of predicted hits, highlighting miR-661, a miRNA with so far no reported role in EMT. MiR-661 was found required for efficient invasion of breast cancer cells by destabilizing two of its predicted mRNA targets, the cell-cell adhesion protein Nectin-1 and the lipid transferase StarD10, resulting, in turn, in the downregulation of epithelial markers. Reexpression of Nectin-1 or StarD10 lacking the 3'-untranslated region counteracted SNAI1-induced invasion. Importantly, analysis of public transcriptomic data from a cohort of 295 well-characterized breast tumor specimen revealed that expression of StarD10 is highly associated with markers of luminal subtypes whereas its loss negatively correlated with the EMT-related, basal-like subtype. Collectively, our non-a priori approach revealed a nonpredicted link between SNAI1-triggered EMT and the down-regulation of Nectin-1 and StarD10 through the up-regulation of miR-661, which may contribute to the invasion of breast cancer cells and poor disease outcome.


Subject(s)
Breast Neoplasms/pathology , Cell Adhesion Molecules/genetics , Cell Dedifferentiation/genetics , MicroRNAs/genetics , Phosphoproteins/genetics , Transcription Factors/physiology , Breast Neoplasms/genetics , Breast Neoplasms/metabolism , Cell Adhesion Molecules/metabolism , Cell Dedifferentiation/drug effects , Cell Dedifferentiation/physiology , Epithelial Cells/metabolism , Epithelial Cells/physiology , Female , Gene Expression/physiology , Gene Expression Profiling , Gene Expression Regulation, Neoplastic/drug effects , Gene Expression Regulation, Neoplastic/physiology , Humans , Mesenchymal Stem Cells/metabolism , Mesenchymal Stem Cells/physiology , MicroRNAs/metabolism , MicroRNAs/physiology , Nectins , Neoplasm Invasiveness , Oligonucleotide Array Sequence Analysis , Phosphoproteins/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism , RNA, Small Interfering/pharmacology , Snail Family Transcription Factors , Transcription Factors/genetics , Transcription Factors/metabolism , Tumor Cells, Cultured , Validation Studies as Topic
7.
East Mediterr Health J ; 15(1): 6-18, 2009.
Article in English | MEDLINE | ID: mdl-19469422

ABSTRACT

Four consecutive annual surveys of 1200 women each were conducted in Lebanon in connection with the National Breast Cancer Awareness campaigns (2002-05) to measure the prevalence of mammography utilization and the impact of these campaigns, and to highlight regional and demographic differences. The utilization of mammography in the previous 12 months was low and increased only slightly over 4 years (from 11% to 18%). In the 2005 campaign, it was twice as high (25%) in greater Beirut than in mostly rural areas, and among women aged 40-59 years (about 21%) compared with younger (12%) or older (11%) women. In each wave, repeat mammograms were less common than first time screening.


Subject(s)
Health Education/organization & administration , Mammography/statistics & numerical data , Patient Acceptance of Health Care/statistics & numerical data , Women , Adult , Age Factors , Breast Neoplasms/diagnosis , Breast Neoplasms/epidemiology , Chi-Square Distribution , Cross-Sectional Studies , Female , Health Care Surveys , Humans , Lebanon/epidemiology , Mass Screening/psychology , Mass Screening/statistics & numerical data , Middle Aged , Needs Assessment , Patient Acceptance of Health Care/psychology , Program Evaluation , Rural Population/statistics & numerical data , Socioeconomic Factors , Urban Population/statistics & numerical data , Women/education , Women/psychology
8.
(East. Mediterr. health j).
in English | WHO IRIS | ID: who-117602

ABSTRACT

Four consecutive annual surveys of 1200 women each were conducted in Lebanon in connection with the National Breast Cancer Awareness campaigns [2002-05] to measure the prevalence of mammography utilization and the impact of these campaigns, and to highlight regional and demographic differences. The utilization of mammography in the previous 12 months was low and increased only slightly over 4 years [from 11% to 18%]. In the 2005 campaign, it was twice as high [25%] in greater Beirut than in mostly rural areas, and among women aged 40-59 years [about 21%] compared with younger [12%] or older [11%] women. In each wave, repeat mammograms were less common than first time screening


Subject(s)
Breast Neoplasms , Awareness , Health Promotion , Early Detection of Cancer , Health Education , Health Services Research , Cross-Sectional Studies , Age Factors , Mammography
9.
J Biol Chem ; 275(23): 17344-8, 2000 Jun 09.
Article in English | MEDLINE | ID: mdl-10747961

ABSTRACT

Sodium butyrate is a multifunctional agent known to inhibit cell proliferation and to induce differentiation by modulating transcription. We have performed differential display analysis to identify transcriptional targets of sodium butyrate in Balb/c BP-A31 mouse fibroblasts. A novel butyrate-induced transcript B-ind1 has been cloned by this approach. The human homologue of this transcript contains an open reading frame that codes for a protein of 370 amino acids without known functional motifs. In transfected cells, the B-ind1 protein has been found to potentiate different effects of the small GTPase Rac1, such as c-Jun N-terminal kinase activation and transcriptional activity of nuclear factor kappaB (NF-kappaB). In addition, we have demonstrated that B-ind1 forms complexes with the constitutively activated Rac1 protein. To investigate the role of B-ind1 in Rac1 signaling, we have constructed several deletion mutants of B-ind1 and tested their ability to affect the activation of NF-kappaB by Rac1. Interestingly, the fragment encoding the median region of human B-ind1 acted as a dominant-negative variant to block Rac1-mediated NF-kappaB activity. These data define B-ind1 as a novel component of Rac1-signaling pathways leading to the modulation of gene expression.


Subject(s)
Butyrates/pharmacology , Fibroblasts/metabolism , Proteins/genetics , Proteins/metabolism , rac1 GTP-Binding Protein/metabolism , Animals , Cell Line , Cloning, Molecular , Fibroblasts/cytology , Fibroblasts/drug effects , Gene Expression Regulation , Humans , Hydro-Lyases , Intracellular Signaling Peptides and Proteins , JNK Mitogen-Activated Protein Kinases , Mice , Mice, Inbred BALB C , Mitogen-Activated Protein Kinases/metabolism , Molecular Sequence Data , NF-kappa B/metabolism , Recombinant Proteins/metabolism , Signal Transduction , Transcription, Genetic , Transfection
10.
Proc Natl Acad Sci U S A ; 96(20): 11217-22, 1999 Sep 28.
Article in English | MEDLINE | ID: mdl-10500157

ABSTRACT

Estrogens induce cell proliferation in target tissues by stimulating progression through the G(1) phase of the cell cycle. Induction of cyclin D1 expression is a critical feature of the mitogenic action of estrogen. We have determined a region between -96 and -29 in the cyclin D1 promoter that confers regulation by estrogens in the human mammary carcinoma cells MCF-7. This region encompasses a unique known transcription factor binding site with a sequence of a potential cAMP response element (CRE-D1). The induction is strictly hormone dependent and requires the DNA binding domain as well as both AF-1 and AF-2 domains of the estrogen receptor (ER) alpha. Destruction of the CRE-D1 motif caused complete loss of estrogen responsiveness. Both c-Jun and ATF-2 transactivated the cyclin D1 promoter in transient transfection experiments, and a clear additional increase was detected when ER was cotransfected with either c-Jun or with c-Jun and ATF-2 but not with ATF-2 alone. Furthermore, the expression of a dominant negative variant of c-Jun, TAM67, completely abolished the induction of the cyclin D1 promoter both in the absence and presence of ER. We show that ATF-2 homodimers and ATF-2/c-Jun heterodimers, but not c-Jun homodimers, were able to bind the CRE of the cyclin D1 promoter. To interpret these results, we propose a mechanism in which ATF-2/c-Jun heterodimers bind to the CRE-D1 element and mediate the activation of cyclin D1 promoter by the ER. This mechanism represents a pathway by which estrogens control the proliferation of target cells.


Subject(s)
Cyclic AMP/pharmacology , Cyclin D1/genetics , Estrogens/pharmacology , Promoter Regions, Genetic , Response Elements , Activating Transcription Factor 2 , Cyclic AMP Response Element-Binding Protein/metabolism , HeLa Cells , Humans , Proto-Oncogene Proteins c-jun/metabolism , Receptors, Estrogen/metabolism , Transcription Factors/metabolism
11.
Biochem J ; 336 ( Pt 3): 639-46, 1998 Dec 15.
Article in English | MEDLINE | ID: mdl-9841876

ABSTRACT

The action of oestrogen hormones is mediated through the oestrogen receptor (ER), a member of a large superfamily of nuclear receptors that function as ligand-activated transcription factors. Sequence-specific transcription factors, including the nuclear receptor superfamily, are thought to interact either directly or indirectly with general transcription factors to regulate transcription. Although numerous studies have focused on the identification of potential co-activators interacting with isolated trans-activation domains of ER, few have investigated the mechanisms by which ER transmits its signal to the basal transcription machinery. We show that ER does not stabilize the binding of the TATA-box binding protein (TBP) of the TFIID complex, or of TFIIB to the promoter, although a stable ER-TBP-TFIIB-promoter complex was detected, suggesting that ER, TBP and TFIIB might interact with each other to form a complex to the promoter. We also demonstrate that ER binds specifically to TFIIB, a key component of the preinitiation complex. Affinity chromatography with immobilized deletion mutants of ER maps a TFIIB interaction region that encompasses the DNA-binding domain. The addition of excess TFIIB to transcription reactions in vitro did not, however, affect the magnitude of transcriptional activation by ER. These results indicate that, in contrast with current models, ER does not activate transcription by increasing the rate of assembly of TFIIB into the transcription complex. An increased concentration of TFIIB was unable, by itself, to overcome the requirement for ER. By using an immobilized promoter-template assay employing nuclear extract from HeLa cells, recombinant human ER increased the stable association of subsequent components of the transcription machinery (TFIIE and TFIIF), in correlation with ER-induced transcription. Our results suggest that ER acts, in an early step, during or immediately after the formation of template-committed complexes containing TFIIB, favouring the recruitment of one or more components of the basic transcription machinery as well as co-activators.


Subject(s)
DNA-Binding Proteins/metabolism , Peptide Chain Initiation, Translational , Receptors, Estrogen/metabolism , Transcription Factors/metabolism , Animals , Binding Sites , Blotting, Western , CHO Cells , Cattle , Cricetinae , Female , Humans , Promoter Regions, Genetic , Spodoptera , TATA-Box Binding Protein , Transcription Factor TFIIB , Transfection
12.
Biochemistry ; 37(17): 6023-32, 1998 Apr 28.
Article in English | MEDLINE | ID: mdl-9558340

ABSTRACT

We have designed a novel estrogen-responsive unit, overERE, which consists of two overlapping ERE separated by 5 bp (center-to-center). In gel retardation assays, this sequence forms a low-mobility complex that migrates like an estrogen receptor tetramer. The receptor-overERE complex was specific and was supershifted by anti-ER H222 antibodies. Dose response studies showed that the formation of the receptor tetramer-overERE complex was cooperative. Truncated receptors were used to assess the contribution of the receptor domains. Deletion of the E domain of the ER prevented the formation of an ER-tetramer complex, which reflects a novel function of this receptor domain. In transfection experiments, 17-beta-estradiol activated transcription from an overERE-containing promoter 4-6 times better than from an ERE-containing promoter. This synergistic effect was observed using either the natural hormone (17-beta-estradiol) or xenoestrogens (phenol red, chlordane). We conclude that two overlapping estrogen-responsive elements can elicit synergistic induction of transcription.


Subject(s)
Estrogens/pharmacology , Genes, Overlapping/physiology , Receptors, Estrogen/metabolism , Transcription, Genetic , Base Sequence , Breast Neoplasms , Carcinoma, Hepatocellular , Chlordan/pharmacology , Dimerization , Drug Synergism , Electrophoresis, Polyacrylamide Gel , Estrogen Antagonists/pharmacology , Estrogens/agonists , Gammaretrovirus/genetics , Genes, Overlapping/drug effects , Genetic Vectors/pharmacology , Humans , Molecular Sequence Data , Phenolsulfonphthalein/pharmacology , Protein Binding/drug effects , Protein Binding/genetics , Protein Structure, Tertiary , Receptors, Estrogen/chemistry , Receptors, Estrogen/genetics , Regulatory Sequences, Nucleic Acid/physiology , Transcription, Genetic/drug effects , Tumor Cells, Cultured , Xenobiotics/pharmacology
13.
Biochem Biophys Res Commun ; 229(1): 163-9, 1996 Dec 04.
Article in English | MEDLINE | ID: mdl-8954100

ABSTRACT

In the mouse fibroblasts BP-A31 as well as in the human epidermoid carcinoma cells KB-3-1, both cyclin D1 mRNA and protein contents decreased rapidly during incubation with sodium butyrate. The decrease of cyclin D1 mRNA was not prevented by cycloheximide indicating that protein synthesis is not required for the inhibition of the expression of cyclin D1 gene by sodium butyrate. The 973 bp region upstream of the human cyclin D1 gene conferred inhibition of the expression of an indicator gene in transiently transfected cells. An 11 base-pair segment situated within this region, with a strong homology to the butyrate-response consensus element identified in butyrate-inducible promoters, also caused an inhibition of transcription under these conditions, indicating that cyclin D1 expression is inhibited by butyrate at the transcriptional level.


Subject(s)
Butyrates/pharmacology , Cyclins/genetics , Gene Expression/drug effects , Histone Deacetylase Inhibitors , Oncogene Proteins/genetics , Oncogenes/genetics , Animals , Butyric Acid , Cells, Cultured , Cyclin D1 , Cyclins/biosynthesis , Dose-Response Relationship, Drug , Humans , Mice , Oncogene Proteins/biosynthesis , Promoter Regions, Genetic/drug effects , RNA, Messenger/biosynthesis
14.
Kidney Int ; 49(4): 1071-8, 1996 Apr.
Article in English | MEDLINE | ID: mdl-8691727

ABSTRACT

IGF-I regulates renal growth and development. Insulin-like growth factor binding proteins (IGFBPs) are synthesized by the kidney and may modulate the local autocrine and/or paracrine actions of IGF-I. We have previously demonstrated that mesangial cells (MC) release IGF-I and IGF-binding activity; however, the specific IGFBPs produced by these cells and the factors involved in their regulation are unknown. We examined MC for expression of IGFBP-1 to -6 mRNAs and proteins. RNase protection assays using total RNA demonstrated that MC express all of the IGFBPs. [125I]IGF-I Western ligand blot of conditioned medium demonstrated that MC release IGFBPs of 24, 29, 32 kDa, and a doublet at 46 kDa, consistent with IGFBP-4, -5, -2 and -3, respectively. IGFBP species of 28 and 34 kDa were also detected. Since IGF-I and TGF-beta are implicated in glomerular hypertrophy and matrix expansion, we tested their effect on IGFBPs released by MC. IGF-I (100 ng/ml), TGF-beta (2 ng/ml) and forskolin (10(-5) M) differentially regulated the abundance of IGFBPs released in the conditioned medium in a time-dependent manner. IGF-I and TGF-beta were potent inducers of the release of IGFBP3 protein; however, TGF-beta, but not IGF-I, increased IGFBP3 mRNA levels. Recombinant IGFBP3 was tested for its effect on IGF-I-induced mitogenesis. IGFBP3 inhibited IGF-I-stimulated DNA synthesis in a dose-dependent manner with a peak effect observed at 50 nM IGFBP3. Although TGF-beta is a potent inhibitor of IGF-I-stimulated DNA synthesis, this effect is not mediated via IGFBPs. Expression of IGFBP-1 to -6 by MC suggests that these proteins may modulate IGF-I bioavailability in the glomerulus. IGF-I itself, TGF-beta and cAMP agonists may indirectly modulate the effects of IGF-I via the release of IGFBPs by MC.


Subject(s)
Glomerular Mesangium/cytology , Insulin-Like Growth Factor Binding Protein 3/chemistry , Insulin-Like Growth Factor Binding Protein 3/metabolism , Colforsin/pharmacology , Culture Media, Conditioned/pharmacology , DNA/biosynthesis , Gene Expression/drug effects , Glomerular Mesangium/chemistry , Humans , Insulin-Like Growth Factor Binding Protein 3/genetics , Insulin-Like Growth Factor I/pharmacology , Protein Binding/physiology , Recombinant Proteins/pharmacology , Transforming Growth Factor beta/pharmacology
15.
Biochem J ; 314 ( Pt 1): 205-13, 1996 Feb 15.
Article in English | MEDLINE | ID: mdl-8660284

ABSTRACT

The role of heat-shock protein 90 (hsp90) in the regulation of the oestrogen receptor (ER) function is less well understood than for other steroid-hormone receptors because hsp90 is not involved in the stabilization or induction of a high-affinity ligand-binding state of ER nor in the inhibition of receptor dimerization. Electrophoretic mobility-shift assays, using purified ER and hsp90, were employed to investigate directly the effect of hsp90 on the ability of ER to bind to the oestrogen-response element (ERE) from the vitellogenin A2 gene. Contrary to models in which hsp90 binds to and passively inactivates steroid-hormone receptors, our studies show that the binding of ER to ERE is inversely dependent on the relative concentration of hsp90. Exposure of purified ER-hsp90 complexes to ERE led to the dissociation of hsp90 and concomitant specific binding of ER to ERE. We demonstrate that the amount of ER-ERE complex decreased with increasing concentrations of hsp90. Furthermore hsp90 dissociated preformed high-affinity ER-ERE complexes. Kinetic dissociation experiments indicate the hsp90 acts in a dynamic and specific process rather than by simple trapping of ER owing to its inherent off-rate. The receptor released from the ERE-bound state by hsp90 was recovered associated with hsp90 and was able to rebind to ERE. These results indicate that hsp90 does not suppress ER function merely by steric hindrance. On the basis of these results and others, we propose that, in vivo, hsp90 may play a dual role in ER function: (i) at a physiological temperature, hsp90 stabilizes an active form of the receptor in accordance with its general molecular chaperone role; (ii) at elevated temperatures or under other environmental stress, the increased cellular concentration of hsp90 negatively interferes with ER-dependent transcription, in accordance with the inhibition of gene transcription attributed to hsp90 after heat shock.


Subject(s)
DNA/metabolism , HSP90 Heat-Shock Proteins/pharmacology , Receptors, Estrogen/metabolism , Regulatory Sequences, Nucleic Acid , Adaptor Protein Complex alpha Subunits , Adaptor Proteins, Vesicular Transport , Animals , Base Sequence , Binding Sites , Cattle , DNA Probes , DNA-Binding Proteins/metabolism , Female , HSP90 Heat-Shock Proteins/isolation & purification , HeLa Cells , Humans , Kinetics , Membrane Proteins/metabolism , Molecular Sequence Data , NFI Transcription Factors , Receptors, Cytoplasmic and Nuclear/metabolism , Receptors, Thyroid Hormone/metabolism , Transcription Factors/metabolism , Transcription, Genetic/genetics
16.
Blood ; 86(2): 598-606, 1995 Jul 15.
Article in English | MEDLINE | ID: mdl-7541671

ABSTRACT

The erythropoietin (Epo) receptor belongs to the cytokine receptor superfamily. Although the cytokine receptors do not possess a tyrosine kinase consensus sequence in the intracellular domain, rapid stimulation of a tyrosine kinase activity occurs after activation by the ligand. We and others have shown that Epo induces the tyrosine phosphorylation of its cognate receptor as well as phosphorylation of other proteins. In this report, we examined the role of the receptor tyrosine residues in signal transduction. Eight tyrosine residues are located within the intracellular domain of the murine Epo receptor. A single tyrosine residue is present in the region previously shown to be sufficient for proliferative signal transduction. This tyrosine (Tyr 343) was mutated to phenylalanine. Moreover, mutant receptors were also generated with either a tyrosine residue or a phenylalanine residue at position 343 and with a COOH terminal truncation that removed the 7 other tyrosine residues. Expression vectors carrying these mutated receptors were transfected into the interleukin-3-dependent murine cell line Ba/F3. Epo-induced growth was sustained efficiently by all these receptors, although receptors without any tyrosine residues conferred a significantly reduced mitogenic activity. Moreover, all receptors were able to mediate Epo-dependant accumulation of beta-globin mRNA. The mutated receptors all induced the tyrosine phosphorylation of several cellular proteins after Epo stimulation. However, the truncated receptors induced the phosphorylation of a reduced number of proteins, suggesting that phosphorylated tyrosines of the receptor could have a role in the recruitment either of a tyrosine kinase or of tyrosine kinase substrate proteins. The receptors were all able to mediate Epo-induced activation of phosphatidylinositol 3-kinase, although truncated receptors no longer bound phosphatidylinositol 3-kinase.


Subject(s)
Erythropoiesis/physiology , Erythropoietin/physiology , Protein Processing, Post-Translational , Protein-Tyrosine Kinases/physiology , Receptors, Erythropoietin/metabolism , Signal Transduction/physiology , Tyrosine/metabolism , Cell Differentiation/drug effects , Cell Line , Enzyme Activation/drug effects , Erythropoiesis/drug effects , Gene Expression Regulation/drug effects , Globins/biosynthesis , Globins/genetics , Hematopoietic Stem Cells/drug effects , Hematopoietic Stem Cells/metabolism , Interleukin-3/pharmacology , Mutagenesis, Site-Directed , Phosphatidylinositol 3-Kinases , Phosphorylation/drug effects , Phosphotransferases (Alcohol Group Acceptor)/metabolism , Phosphotyrosine , Protein Processing, Post-Translational/drug effects , Receptors, Erythropoietin/genetics , Recombinant Fusion Proteins/metabolism , Sequence Deletion , Signal Transduction/drug effects , Transfection , Tyrosine/analogs & derivatives
17.
Eur J Biochem ; 216(3): 821-8, 1993 Sep 15.
Article in English | MEDLINE | ID: mdl-8404901

ABSTRACT

Stimulation of sensitive cells with erythropoietin results in rapid induction of protein tyrosine phosphorylation. Other than tyrosine phosphorylation of one chain of the erythropoietin receptor, the identities of the remaining tyrosine-phosphorylated proteins are undefined. In this report, we demonstrate that the stimulation of the erythropoietin-sensitive human UT7 cells by erythropoietin rapidly resulted in the appearance of phosphatidylinositol 3-kinase activity in anti-phosphotyrosine immunoprecipitates. Erythropoietin action was rapid, detectable after as early as 1 min stimulation, transient, returning to control level after 30 min stimulation and was observed using the erythropoietin concentrations able to stimulate the cell proliferation. Anti-(phosphatidylinositol 3-kinase) antibodies specifically immunoprecipitated 125I-erythropoietin bound to its receptor, strongly suggesting that phosphatidylinositol 3-kinase associated with a protein complex containing the activated erythropoietin receptor. To confirm this result, phosphatidylinositol 3-kinase was immunoprecipitated from erythropoietin-stimulated cells using mild conditions followed by Western analysis using anti-phosphotyrosine antibodies. Five tyrosine phosphorylated proteins were revealed: the cloned chain of the erythropoietin receptor, the regulatory subunit of phosphatidylinositol 3-kinase and three unidentified proteins of 111, 97 and 64 kDa. None of these tyrosine phosphorylated proteins was detected in anti-(phosphatidylinositol 3-kinase) immunoprecipitates from unstimulated cells. Thus, our results show that phosphatidylinositol 3-kinase associates with a tyrosine-phosphorylated protein complex containing the activated erythropoietin receptor.


Subject(s)
Erythropoietin/pharmacology , Phosphotransferases (Alcohol Group Acceptor)/metabolism , Proteins/metabolism , Receptors, Erythropoietin/metabolism , Tyrosine/metabolism , Cell Line , Chromatography, High Pressure Liquid , Electrophoresis, Polyacrylamide Gel , Growth Substances/pharmacology , Humans , Phosphatidylinositol 3-Kinases , Phosphorylation , Precipitin Tests
18.
Biochem Biophys Res Commun ; 185(3): 944-52, 1992 Jun 30.
Article in English | MEDLINE | ID: mdl-1627146

ABSTRACT

DNA bending is increasingly proposed as an essential step for the establishment of the multiprotein complexes required for transcription initiation. Polyamines and metallic cations, known to promote DNA-bending, enhance the binding of purified estrogen receptor (ER) to the estrogen response element (ERE) of the Xenopus vitellogenin A2 gene. Using both circular permutation electrophoretic mobility and cyclization assays, we provide evidence that ER bends the DNA at the estrogen response element. The same bending occurs as a result of estrogen receptor protein binding independently of its conformational changes induced by hormone or anti-hormone. We suggest a role of the observed DNA bending in estrogen-regulated transcription.


Subject(s)
Calcium/pharmacology , DNA-Binding Proteins/metabolism , Genes, Regulator , Magnesium/pharmacology , Polyamines/pharmacology , Receptors, Estrogen/metabolism , Transcription, Genetic , Vitellogenins/genetics , Zinc/pharmacology , Animals , Base Sequence , Binding Sites , DNA/chemistry , DNA/drug effects , DNA/genetics , DNA Probes , Distamycins/pharmacology , Kinetics , Molecular Sequence Data , Mutagenesis, Insertional , Nucleic Acid Conformation/drug effects , Oligodeoxyribonucleotides , Oligonucleotide Probes , Plasmids , Polymerase Chain Reaction , Receptors, Estrogen/drug effects , Transcription, Genetic/drug effects , Xenopus
19.
J Chir (Paris) ; 129(5): 254-6, 1992 May.
Article in French | MEDLINE | ID: mdl-1429925

ABSTRACT

Eleven cases of sigmoid volvulus in patients aged 76 years in average, without visible signs of necrosis on endoscopy, are reported. All patients were treated within 6 to 48 hours by colic resection and immediate restoration of continuity with a mechanical anastomosis. Morbidity was low, including one case of evisceration and one of pneumonia, and there was no mortality after three months. Early resection seems to prevent the risks of necrosis and recurrence, and to have a good prognosis for survival.


Subject(s)
Intestinal Obstruction/surgery , Sigmoid Diseases/surgery , Aged , Aged, 80 and over , Anastomosis, Surgical , Catheterization , Emergencies , Female , Humans , Male , Postoperative Complications
20.
J Urol (Paris) ; 97(6): 287-90, 1991.
Article in French | MEDLINE | ID: mdl-1804879

ABSTRACT

The authors report the case of a 44 years old male patient, admitted for a left inguinal hernia. Multiple scrotal cysts were discovered and removed at surgery. Histological study showed an idiopathic calcinosis of the scrotum.


Subject(s)
Calcinosis/pathology , Genital Diseases, Male/pathology , Scrotum/pathology , Adult , Calcinosis/surgery , Genital Diseases, Male/surgery , Humans , Male , Scrotum/surgery
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