关键词： AMPK   AM251   cannabinoid antagonist   JNK   ATF3  

摘要： AM251, a cannabinoid antagonist, has various biological activities. In this study, we found that AM251 suppressed the viability of hepatoma HepG2 cells and also increased phosphorylation of JNK (c-jun N-terminal kinase) and ATF3 (activating transcription factor 3). In addition, AM251 phosphorylated AMPK (AMP-activated protein kinase) in a time and dose-dependent manner. Inhibition of AMPK blocked AM251-induced JNK/ATF3 phosphorylation. Expression of AMPK or treatment with AICAR (5-aminoimidazole-4-carboxy-amide-1-D-ribofuranoside), an AMPK activator, activated the JNK/ATF3 pathways. Together, these results suggest that AM251 may have anti-tumor effects in hepatoma through activation of the AMPK-JNK-ATF3 signal pathway. (c) 2008 Published by Elsevier Inc.

关键词： MMP   ADC   gene   enos   ATF3  

摘要： Objective In this study we will investigate the effect and possible mechanism of agmatine on MMP *** We established a transfection of human ADC gene into the murine bEnd.3 cells(bEnd.3-ADC)by the retroviral packaging cell line *** bEnd.3-ADC cells were maintained in the hypoxia chamber for 6 hours,then returned to a normoxic incubator with glucose for 16 *** performed RT-PCR and western blot analysis against MMP-2,MMP-9,eNOS and ATF3,and measured the production of NO using Griess *** determine the possible mechanism of agmatine on MMP expression we used inhibitory *** The expression of MMP was decreased by agmatine administered exogenously and endogenously,while eNOS was *** showed L-NAME(NOS inhibitor)altered the suppression of MMP-9 by exogenously administered *** seems that MMP-9 suppression by exogenously administrated agmatine is mediated,at least in part,via *** also found that ATF3 was increased significantly in ADC overexpression cells,but it was attenuated by NOS ***,we found the suppression of MMP by agmatine was attenuated in cells transfected with ATF3 *** Our study suggested that endogenously administered agmatine suppress the MMP-2 and MMP-9 expression via eNOS-ATF3-MMPs pathway.

摘要： Introduction ATF3, gène œstrogéno-dépendant exprimé durant le développement génital, est considéré comme un gène candidat de l’hypospadias du fait de son expression anormalement élevée dans le prepuce d’hypospades, et du fait de son implication dans l’arrêt du cycle cellulaire qui pourrait interférer avec la croissance urétrale. Le but de cette étude est de préciser l’implication d’ATF3 dans l’hypospadias en réalisant son séquençage chez des patients hypospades et en étudiant son expression dans le tubercule génital de fœtus humains. Matériel et méthode Le séquençage des exons codants et des sites d’épissage d’ATF3 a été réalisé chez 41 garçons porteurs d’hypospadias de sévérité variable et chez 30 contrôles. L’expression d’ATF3 dans le tubercule génital de fœtus humains avec et sans hypospadias a été étudiée par immunohistochimie. Résultats - La mutation missense (Leu23Met) a été identifiée chez un garcon porteur d’un hypospadias antérieur. Cette acide aminé, habituellement hautement conservé à travers les espèces, pourrait avoir un rôle fonctionnel significatif. - Trois mutations (C53070T, C53632A, Ins53943A) ont été identifiées dans ou à proximité de l’exon 6. Cette région importante comprend une zone d’épissage alternatif à l’origine de la fomre ATF3Δ zip. Cette forme alternative est impliquée dans la régulation de la fonction d’ATF3. Ces mutations pourraient donc être altérer sa formation et ainsi la régulation de l’action d’ATF3. Les phénotypes associés à ces mutations étaient des hypospadias périnéal, pénoscrotal et antérieur. Aucune mutation n’a été identifiée chez les contrôles. - ATF3 n’est pas exprimé dans l’urètre du fœtus normal. Il est par contre exprimé de façon aberrante dans la plaque urétrale chez le fœtus hypospade, en particulier au niveau de l’orifice urétral ectopique. Conclusion Nous rapportons les premières mutations du gène ATF3 chez des patients porteurs d’hypospadias. Ces résultats, associés à une expression aberrante d’ATF3 dans l’urètre

关键词： Recombinant proteins  

摘要： ATF3 stimulated promoter activity of EphA1 by 3.4-fold in ATF3-dependent angiogenesis in vitro. Although tyrosine kinase activation of EphA1 was dispensable, binding of EphA1 to fibronectin through its type I repeat played an essential role in the angiogenesis. Recombinant proteins containing fibronectin 10th to 12th type I repeat (I10-12) but not I 12 could inhibit the angiogenesis in vitro by competitively targeting EphA1 with the full-length fibronectin. However, I 12 acquired a higher affinity toward EphA2 with K-d 18 nM and inhibited vascular endothelial growth factor-dependent angiogenic invasion in a Matrigel plug assay.

关键词： ATF3   transcriptional regulation   cancer cell dichotomy   cell motility   breast cancer   adaptive response  

摘要： Activating transcription factor 3 (ATF3) is a member of the ATF/cyclic AMP response element-binding family of transcription factors. We present evidence that ATF3 has a dichotomous role in cancer development. By both gain- and loss-of-function approaches, we found that ATF3 enhances apoptosis in the untransformed MCF10A mammary epithelial cells, but protects the aggressive MCF10CA1a cells and enhances its cell motility. Array analyses indicated that ATF3 upregulates the expression of several genes in the tumor necrosis factor pathway in the MCF10A cells but upregulates the expression of several genes implicated in tumor metastasis, including TWIST1, fibronectin (FN)-1, plasminogen activator inhibitor-1, urokinase-type plasminogen activator, caveolin-1 and Slug, in the MCF10CA1a cells. We present evidence that ATF3 binds to the endogenous promoters and regulates the transcription of the TWIST1, FN-1, Snail and Slug genes. Furthermore, conditioned medium experiments indicated that ATF3 has a paracrine/autocrine effect, consistent with its upregulation of genes encoding secreted factors. Finally, ATF3 gene copy number is > 2 in similar to 80% of the breast tumors examined (N = 48) and its protein level is elevated in similar to 50% of the tumors. These results provided a correlative argument that it is advantageous for the malignant cancer cells to express ATF3, consistent with its oncogenic roles suggested by the MCF10CA1a cell data.

关键词： 尿道下裂/病理学   尿激酶   基因表达  

摘要： 目的研究激活转录因子3(Activating transcription factor 3,ATF3)在尿道下裂包皮组织中的表达情况,探索ATF3与散发的单纯性尿道下裂之间的关系。方法采用免疫组织化学方法,在蛋白质水平检测ATF3蛋白在散发的单纯性尿道下裂患者和对照组之间的表达情况。采用RT-PCR的方法,在RNA水平检测ATF3mRNA在两组之间的表达差异。结果ATF3蛋白在散发的单纯性尿道下裂中的阳性表达率为90%(27/30),在对照组中为10%(2/20),两组比较,差异有统计学意义(P<0.05)。散发的单纯性尿道下裂患者ATF3mRNA的相对表达量为0.5375±0.0591,对照组相对表达量为0.4193±0.0678,两组比较,差异有统计学意义。从数据上看,重型组中ATF3mRNA相对表达量高于其它两组。结论正常人包皮组织中ATF3表达量很少,散发的单纯性尿道下裂患者包皮组织中ATF3的表达明显增多,提示ATF3和散发的单纯性尿道下裂关系密切。进一步研究尿道下裂中ATF3产生的分子基础和ATF3相关的信号转导通路,有可能揭示散发的单纯性尿道下裂的病因。

摘要： Purpose ATF3, an estrogen-responsive gene expressed during genital development, is a strong candidate gene in the development of hypospadias. It is indeed the most upregulated gene in hypospadiac skin and it is implicated in cell cycling suppression that may interfere with urethral cell growth. We thus investigated the sequence and the expression of ATF3 in hypospadias. Material and Methods Direct sequencing of coding exons and splicing sites of ATF3 was performed in 41 boys with hypospadias and 30 controls. ATF3 expression in the genital tubercle of fetuses with and without hypospadias was also studied by immunochemistry. Results -A missense mutation (Leu23Met) was identified in a boy with anterior hypospadias. This aminoacid is highly conserved through species and may be of functional interest. -3 mutations (C53616T, C54177A, Ins54489A) were found in or close to exon 6. This important exon includes splicing sites for an alternative transcript (ATF3ΔZip) implicated in the regulation of the function of ATF3. The phenotypes associated with these mutations were perineal, penoscrotal and anterior hypospadias. None of these mutations were present in controls. -Immunochemistry revealed that ATF3, which is undetectable around the urethra in normal fetus, is overexpressed in the urethral plate and subcutaneous tissue of hypospadiac specimen, especially around the ectopic orifice of urethra. Conclusions This first report of ATF3 mutations in hypospadias, coupled with its particular expression pattern in hypospadiac fetus, highlight the role of ATF3 in this frequent malformation. These results further support the importance of estrogen responsive genes in the development of hypospadias.

关键词： Transcription factors  

摘要： Nerve injury requires the expression of large ensembles of genes. The key molecular mechanism for this gene transcription regulation in injured neurons is poorly understood. Among many nerve injury-inducible genes, the gene encoding damage-induced neuronal endopeptidase (DINE) showed most marked expression response to various kinds of nerve injuries in central and peripheral nervous system neurons. This unique feature led us to examine the promoter region of the DINE gene and clarify both the injury-responsive element within the promoter and its related transcriptional machinery. This study showed that DINE promoter was activated by leukemia inhibitory factor and nerve growth factor withdrawal, which were pivotal for the up-regulation of DINE mRNA after nerve injury. The injury-inducible transcription factors such as activating transcription factor 3 (ATF3), c-Jun, and STAT3, which were located at the downstream of leukemia inhibitory factor and nerve growth factor withdrawal, seemed to be involved in the activation of the DINE promoter. Surprisingly, these transcription factors did not bind to the DINE promoter directly. Instead, the general transcription factor, Sp1, bound to a GC box within the promoter. ATF3, c-Jun, and STAT3 interacted with Sp1 and are associated with the GC box region of the DINE gene in injured neurons. These findings suggested that Sp1 recruit ATF3, c-Jun, and STAT3 to obtain the requisite synergistic effect. Of these transcription factors, ATF3 may be the most critical, because ATF3 is specifically expressed after nerve injury.

关键词： Fra1   ATF3   MAP kinases   DNA damage   apoptosis   cell cycle  

摘要： JNK and ERK MAP kinases regulate cellular responses to genotoxic stress in a cell type and cell context- dependent manner. However, the factors that determine and execute JNK- and ERK-controlled stress responses are only partly known. In this study, we investigate the roles of the AP-1 components ATF3 and Fra1 in JNK- and ERK-dependent cell cycle arrest and apoptosis. We show that the anti-cancer drug cisplatin or UV light activates both JNK and ERK in human glioblastoma cells lacking functional p53. Inhibition experiments of JNK or ERK activities revealed that the ERK pathway strongly promotes cisplatin- and UV-induced apoptosis in these glioblastoma cells. Furthermore, JNK but not ERK is required for ATF3 induction, and both ERK and JNK are necessary for post-transcriptional induction of Fra1 in response to cisplatin or UV. Knock-down of ATF3 and Fra1 results in increased and decreased cisplatin-induced apoptosis, respectively, indicating that ATF3 is an anti-apoptotic JNK effector and Fra1 is a pro- apoptotic ERK/JNK effector. Knock-down experiments also revealed that ATF3 and Fra1, respectively, enhance and reduce S-phase arrest through differential modulation of the Chk1-Cdk2 pathway. Thus, we identify novel reciprocal functions of ATF3 and Fra1 in JNK- and ERK-dependent DNA damage responses. (c) 2007 Elsevier B.V. All rights reserved.

摘要： OBJECTIVE-P-Cell failure is an essential component of all types of diabetes, and the insulin receptor substrate 2 (IRS2) branch of signaling plays a key role in beta-cell survival and function. We tested the hypothesis that activating transcription factor 3 (ATF3), a stress-inducible proapoptotic gene, downregulates the expression of IRS2 in beta-cells. RESEARCH DESIGN AND METHODS-We used both the gain- and loss-of-function approaches to test the effects of ATF3 on IRS2 gene expression. We also analyzed the binding of ATF3 to the IRS2 promoter by chromatin immunoprecipitation assay and the transcription of the IRS2 gene by polymerase II occupancy assay. Furthermore, we tested the ability of IRS2 to alleviate the proapoptotic effects of ATF3 in cultured beta-cells and in transgenic mice using the rat insulin promoter to drive the transgenes. RESULTS-Expression of ATF3 is sufficient to reduce IRS2 gene expression;in contrast, knockdown or knockout of ATF3 reduces the ability of stress signals to downregulate IRS2 expression. ATF3 binds to the IRS2 promoter in vivo, and the binding of ATF3 correlates with decreased IRS2 gene transcription. Functionally, expression of IRS2 protects beta-cells from ATF3-induced apoptosis. CONCLUSIONS-IRS2 is a target gene of ATF3, and its repression by ATF3 contributes, at least partly, to the apoptosis induced by ATF3. Because ATF3 is a stress-inducible gene, our work provides a direct link to explain how environmental stress factors can modulate IRS2 gene transcription.