关键词： 结直肠肿瘤/病理学   ATF3   CyclinD1   Maspin   免疫组织化学  

摘要： 目的:检测转录激活因子3(ATF3)及其靶基因Cyclin D1与Maspin在结直肠癌组织芯片中的表达,探讨ATF3表达在结直肠癌发生、发展中的意义。方法:构建含结直肠癌及癌旁相对正常肠黏膜的组织芯片,应用免疫组织化学检测ATF3、Cyclin D1及Maspin的表达情况。结果:ATF3、Cyclin D1与Maspin在结直肠癌中阳性表达率分别为70.3%、51.4%和59.5%,明显高于癌旁正常组织的21.6%、2.7%和13.5%,差异有统计学意义,χ2值分别为35.252、44.411和33.689,P值均为0.000;ATF3与结直肠癌患者的性别、年龄、肿瘤部位、肿瘤大小及肿瘤分化程度无关,而与浸润程度和淋巴结有无转移有关,浆膜层表达(83.3%)高于肌层(38.9%),有淋巴结转移(92.3%)高于无淋巴结转移(45.7%),χ2值分别为13.290和17.110,P值均为0.000;Cyclin D1与结直肠癌患者的性别、年龄、肿瘤部位及肿瘤大小无关,而与病理学分级、浸润程度和淋巴结有无转移有关,低分化组织表达(71.4%)高于高中分化组织(39.1%),浆膜层表达(61.1%)高于肌层(28.8%),有淋巴结转移(69.2%)高于无淋巴结转移(31.4%),χ2值分别为7.268、6.019和10.550,P值分别为0.007、0.014和0.001;Maspin与结直肠癌患者的性别、年龄、肿瘤部位、肿瘤大小、肿瘤分化程度、浸润深度及有无淋巴结转移均无关,P值均>0.05。ATF3、Cyclin D1与Maspin在结直肠癌中均高表达,ATF3与Cyc-lin D1在结直肠癌中表达呈正相关(r=0.362,P=0.000),与Maspin表达无明显相关(r=0.075,P=0.513)。结论:ATF3表达与结直肠癌的发生密切相关,ATF3可能通过调控Cyclin D1表达而促进结直肠癌的发生发展及侵袭转移。

摘要： MicroRNA-494 mediates apoptosis and necrosis in several types of cells, but its renal target and potential role in AKI are unknown. Here, we found that microRNA-494 binds to the 3'UTR of activating transcription factor 3 (ATF3) and decreases its transcription. In mice, overexpression of microRNA-494 significantly attenuated the level of ATF3 and induced inflammatory mediators, such as IL-6, monocyte chemotactic protein-1, and P-selectin, after renal ischemia/reperfusion, exacerbating apoptosis and further decreasing renal function. Activation of NF-kappa B mediated this proinflammatory response. In this ischemia/reperfusion model, urinary levels of microRNA-494 increased significantly before the rise in serum creatinine. In humans, urinary microRNA-494 levels were 60-fold higher in patients with AKI than normal controls. In conclusion, upregulation of microRNA-494 contributes to inflammatory or adhesion molecule-induced kidney injury after ischemia/reperfusion by inhibiting expression of ATF3. Furthermore, microRNA-494 may be a specific and noninvasive biomarker for AKI.

关键词： HDAC   bZIP   JDP2   ATF3   Histone acetylation   Repressor  

摘要： JDP2, is a basic leucine zipper (bZIP) protein displaying a high degree of homology with the stress inducible transcription factor, ATF3. Both proteins bind to cAMP and TPA response elements and repress transcription by multiple mechanisms. Histone deacetylases (HDACs) play a key role in gene inactivation by deacetylating lysine residues on histones. Here we describe the association of JDP2 and ATF3 with HDACs 1, 2-6 and 10. Association of HDAC3 and HDAC6 with JDP2 and ATF3 occurs via direct protein-protein interactions. Only part of the N-terminal bZIP motif of JDP2 and ATF3 basic domain is necessary and sufficient for the interaction with HDACs in a manner that is independent of coiled-coil dimerization. Class I HDACs associate with the bZIP repressors via the DAC conserved domain whereas the Class IIb HDAC6 associates through its C-terminal unique binder of ubiquitin Zn finger domain. Both JDP2 and ATF3 are known to bind and repress the ATF3 promoter. MEF cells treated with histone deacetylase inhibitor, trichostatin A (TSA) display enhanced ATF3 transcription. ATF3 enhanced transcription is significantly reduced in MEF cells lacking both ATF3 and JDP2. Collectively, we propose that the recruitment of multiple HDAC members to JDP2 and ATF3 is part of their transcription repression mechanism. (C) 2012 Elsevier B.V. All rights reserved.

关键词： Gene Regulation   Gene Transcription   Histidine   Histone Deacetylase Inhibitors   Nutrition   ATF3   Asparagine Synthetase   Dietary Protein   Histone Demethylase   Nutrient Sensing  

摘要： Following amino acid deprivation, the amino acid response (AAR) induces transcription from specific genes through a collection of signaling mechanisms, including the GCN2-eIF2-ATF4 pathway. The present report documents that the histone demethylase JMJD3 is an activating transcription factor 4 (ATF4)-dependent target gene. The JMJD3 gene contains two AAR-induced promoter activities and chromatin immunoprecipitation (ChIP) analysis showed that the AAR leads to enhanced ATF4 recruitment to the C/EBP-ATF response element (CARE) upstream of Promoter-1. AAR-induced histone modifications across the JMJD3 gene locus occur upon ATF4 binding. Jmjd3 transcription is not induced in Atf4-knock-out cells, but the AAR-dependent activation was rescued by inhibition of histone deacetylation with trichostatin A (TSA). The TSA rescue of AAR activation in the absence of Atf4 also occurred for the Atf3 and C/EBP homology protein (Chop) genes, but not for the asparagine synthetase gene. ChIP analysis of the Jmjd3, Atf3, and Chop genes in Atf4 knock-out cells documented that activation of the AAR in the presence of TSA led to specific changes in acetylation of histone H4. The results suggest that a primary function of ATF4 is to recruit histone acetyltransferase activity to a sub-set of AAR target genes. Thus, absolute binding of ATF4 to these particular genes is not required and no ATF4 interaction with the general transcription machinery is necessary. The data are consistent with the hypothesis that ATF4 functions as a pioneer factor to alter chromatin structure and thus, enhance transcription in a gene-specific manner.

摘要： Biomarkers predicting metastatic capacity might assist the development of better therapeutic strategies for aggressive cancers such as lung cancer. In this study, we show that adenylate kinase-4 (AK4) is a progression-associated gene in human lung cancer that promotes metastasis. Analysis of published microarray data showed that AK4 was upregulated in lung adenocarcinoma compared with normal cells. High AK4 expression was associated with advanced stage, disease recurrence and poor prognosis. Loss of AK4 expression suppressed the invasive potential of lung cancer cell lines, whereas AK4 overexpression promoted invasion in vitro and in vivo. Mechanistically, the transcription factor ATF3 was identified as a pivotal regulatory target of AK4. Simultaneous reduction in AK4 and ATF3 expression abolished the inhibitory effects of ATF3 on invasion. ATF3 overexpression in AK4-overexpressing cells limits invasion activity. Furthermore, patients with high AK4 and low ATF3 expression showed unfavorable outcomes compared with patients with low AK4 and high ATF3 expression. Taken together, our findings indicated that AK4 promotes malignant progression and recurrence by promoting metastasis in an ATF3-dependent manner. Cancer Res;72(19);5119-29. (C)2012 AACR.

摘要： PS-341 (bortezomib), a proteasome inhibitor, has been approved for the treatment of multiple myeloma. Our previous work has shown that PS-341 induces death receptor 5 (DR5)-dependent apoptosis and enhances the TNF-related apoptosis-inducing ligand-induced apoptosis in human non-small cell lung cancer cells. However, the definite mechanism remains undefined. In the present study, we reveal that PKC delta and RSK2 mediate PS-341-induced DR5 upregulation, involving coactivation of endoplasmic reticulum (ER) stress. We discovered that PS-341 activated ER stress through elevating the expression of BiP, p-eIF2 alpha, IRE1 alpha, ATF4, ATF3, and CCAAT/enhancer-binding protein homologous protein (CHOP). Further study showed that DR5 upregulation was dependent on ATF4, ATF3, and CHOP expression. Silencing either one of the ATF4, ATF3, and CHOP expression decreased DR5 upregulation and subsequent apoptosis. We determined that ATF4 regulated ATF3 and CHOP expression. Thereafter, ATF3 and CHOP formed a complex and regulated DR5 expression. In addition, we discovered that the phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 and RSK2 were elevated after PS-341 treatment and inhibition of their phosphorylation using MAP-ERK kinase 1/2 inhibitor decreased the DR5 level, indicating that ERK/RSK2 signaling is involved in DR5 upregulation. Furthermore, we detected the cleavage of PKC delta, and the blockage of PKC delta expression cut down DR5 upregulation and apoptosis. Importantly, knockdown of PKC delta expression decreased the induction of ER stress and the phosphorylation of ERK1/2 and RSK2, suggesting that PKC delta regulates DR5 expression through ERK/RSK2 signaling and ATF4-CHOP/ATF3 axis. Collectively, we show that PS-341 induces PKC delta-dependent DR5 expression through activation of ERK/RSK2 and ER stress signaling pathway. Mol Cancer Ther;11(10);2174-82. (C) 2012 AACR.

关键词： TRPV1   Pain   Capsaicin   Vanilloid   Nociception   Resiniferatoxin   ATF3   Dorsal root ganglion   MRS1477   Adelta fiber  

摘要： Background: The prevalence of long-term opiate use in treating chronic non-cancer pain is increasing, and prescription opioid abuse and dependence are a major public health concern. To explore alternatives to opioid-based analgesia, the present study investigates a novel allosteric pharmacological approach operating through the cation channel TRPV1. This channel is highly expressed in subpopulations of primary afferent unmyelinated C-and lightly-myelinated Ad-fibers that detect low and high rates of noxious heating, respectively, and it is also activated by vanilloid agonists and low pH. Sufficient doses of exogenous vanilloid agonists, such as capsaicin or resiniferatoxin, can inactivate/deactivate primary afferent endings due to calcium overload, and we hypothesized that positive allosteric modulation of agonist-activated TRPV1 could produce a selective, temporary inactivation of nociceptive nerve terminals in vivo. We previously identified MRS1477, a 1,4-dihydropyridine that potentiates vanilloid and pH activation of TRPV1 in vitro, but displays no detectable intrinsic agonist activity of its own. To study the in vivo effects of MRS1477, we injected the hind paws of rats with a non-deactivating dose of capsaicin, MRS1477, or the combination. An infrared diode laser was used to stimulate TRPV1-expressing nerve terminals and the latency and intensity of paw withdrawal responses were recorded. qRT-PCR and immunohistochemistry were performed on dorsal root ganglia to examine changes in gene expression and the cellular specificity of such changes following treatment. Results: Withdrawal responses of the capsaicin-only or MRS1477-only treated paws were not significantly different from the untreated, contralateral paws. However, rats treated with the combination of capsaicin and MRS1477 exhibited increased withdrawal latency and decreased response intensity consistent with agonist potentiation and inactivation or lesion of TRPV1-containing nerve terminals. The loss of n

关键词： ATF3   cerebral ischemia   inflammation   NF-kappa B   CREB  

摘要： Background and Purpose: Activating transcription factor 3 (ATF3) is a stress-induced transcription factor that has been shown to repress inflammatory gene expression in multiple cell types and diseases. This study was conducted to investigate the role of ATF3 in the pathological processes of cerebral ischemia and its influence on post-ischemic inflammation. Methods: Wild-type (WT) and ATF3 knockout (KO) mice were subjected to middle cerebral artery occlusion (45 min) followed by reperfusion. Infarct volume, brain edema, and neurological deficits were examined. Neural apoptosis, inflammatory gene expression, cellular inflammatory response and Matrix Metallo Proteinases 9 (MMP9) activity were assessed. Activity of the nuclear factor-kappa B (NF-kappa B) signaling pathway and cAMP-responsive element-binding protein (CREB) was studied. Results: Knockout of ATF3 significantly exacerbated the infarct volume and worsened neurological function after brain ischemia. Neural apoptosis, inflammatory gene expression and cellular inflammatory response were upregulated in ATF3 KO mice. The MMP9 mRNA expression and protein activity were increased in ATF3 KO mice. KO of ATF3 led to an elevation in the activity of the NF-kappa B signaling pathway and inhibition of CREB activity. Conclusions: Our study demonstrated that ATF3 was markedly induced by brain ischemia. ATF3 deficiency exacerbated the inflammatory response and brain injury after cerebral ischemia, potentially through further activation of the NF-kappa B signaling pathway. ATF3 is likely an important protective regulator in cerebral ischemic injury. (C) 2012 IBRO. Published by Elsevier Ltd. All rights reserved.