关键词： ATF3   Cell death   Pancreatic beta-cells   Stress-regulated signal transduction  

摘要： Currently there are 20 million people diagnosed with diabetes in the United States and the incidence is expected to increase by 42% over the next twenty years. Type 1, or insulin-dependent diabetes, is an autoimmune disorder characterized by infiltration of activated T-lymphocytes into the pancreas. Auto-reactive immune cells initiate β-cell destruction by several mechanisms including secretion of soluble factors (cytokines), direct cell-cell contact, and activation of osmotic lysis signals. Type 2, or insulin-independent diabetes, is characterized by insulin resistance in the peripheral tissues such as the liver, fat, and skeletal muscle. Phosphorylation of key substrates involved in the insulin signal transduction pathway by stress-activated protein kinases contributes to the insulin resistance and prevents the uptake of glucose from the blood. Recent reports suggest that type 2 diabetes is a slower progressing form of type 1 and that β-cell apoptosis contributes to the pathogenesis of both forms. Activating Transcription Factor 3 (ATF3) is a member of the ATF/CREB family of transcription factors which regulate gene expression through their ability to bind a common DNA sequence motif (TGACGTCA). Levels of endogenous ATF3 are extremely low in most tissues or cell types; however, ATF3 has been characterized as an immediate-early gene whose expression is up-regulated during the stress response. Prior to this work and during its undertaking several reports were published which describe the physiological outcomes of ATF3 expression during the stress response. These reports demonstrate a variety roles for ATF3 including protection from stress-induced apoptosis in neurons, promotion of apoptosis in endothelial cells, and enhancement of metastatic potential in colon cancer cells. In addition, transgenic mice which ectopically express ATF3 in endocrine precursor cells during development showed defects in pancreatic islet formation. Based on this information, we set out to

关键词： DRG neuron   axotomy   serpin   protease inhibitor   ATF3   plasminogen activator  

摘要： We have previously found that tissue type and urokinase type plasminogen activators (tPA and uPA) are induced in dorsal root ganglia (DRG) neurons after peripheral axotomy and that tPA plays crucial roles in generating neuropathic pain. Here we examined whether the plasminogen activator inhibitor-1 and -2 (PAI-1 and PAI-2) mRNA, endogenous inhibitors of tPA and uPA, are induced in the DRG following sciatic nerve transection. L4 and L5 DRG sections were examined using in situ hybridization histochemistry. The results showed that both PAI-1 and PAI-2 mRNA were up-regulated in DRG neurons within 1 day, and peaked at 1-3 days, after injury. Reduction of these mRNA was observed from 7 days after injury. The precise expression patterns of PAI-1 and PAI-2 mRNA at 3 days after axotomy revealed that PAI-1 mRNA was observed in predominantly small neurons, while much of the PAI-2 mRNA was expressed in large neurons. Double-labeling analysis of these mRNAs with activated transcription factor 3, known as an injury marker, revealed that most PAI-1 and PAI-2 mRNAs was induced in injured neurons. Co-expression of PAI-1, 2 with tPA and uPA in DRG neurons suggests that these inhibitors may act in an autocrine manner to modulate extracellular proteolytic activity after nerve injury. (c) 2005 IBRO. Published by Elsevier Ltd. All rights reserved.

摘要： Several agonists acting on G protein-coupled receptors (GPCR) enhance the mitogenic effect of epidermal growth factor (EGF) in rat hepatocytes, through mechanisms that have only partially been clarified. Results in various cells have led to the idea that a major mechanism for GPCR-mediated stimulation of cell growth is transactivation of receptor tyrosine kinases, particularly the EGF receptor (EGFR), leading to rapid phosphorylation of the EGFR and activation of downstream signaling pathways. In the present study cultured rat hepatocytes were exposed to various GPCR agonists, including vasopressin, angiotensin II (***), norepinephrine, or prostaglandin F-2alpha (PGF(2alpha)). None of these agents increased the phosphorylation of the EGFR or the docking protein Shc. Furthermore, we examined the effect of the GFCR agonists on the expression of two early response genes believed to be involved in growth activation. The GPCR agonists increased the mRNA expression of c-myc, and also of activating transcription factor 3 (ATF3)/liver regeneration factor-1 (LRF-1), which is a novel finding. Finally, the selective EGFR inhibitor AG1478 did not suppress the activation of extracellular signal-regulated kinase 112 (ERK1/2) or the induction of c-myc or ATF3/LRF-1 by the GPCR agonists, and did not prevent the comitogenic effects induced by these agents, while it blocked the effect of EGF on these responses. The results suggest that GPCR agonists induce expression of ATF3/LRF-1 and c-myc and exert comitogenic effects through mechanisms that do not require EGFR transactivation. (C) 2004 Wiley-Liss, Inc.

关键词： ATF3   activating transcription factor 3   EC   (−)-epicatechin   ECG   (−)-epicatechin gallate   EGC   (−)-epigallocatechin   EGCG   (−)-epigallocatechin gallate   NAG-1   NSAID-activated gene-1   NSAIDs   non-steroidal anti-inflammatory drugs   PARP   poly(ADP-ribose) polymerase   TSP1   thrombospondin-1  

摘要： There is persuasive epidemiological and experimental evidence that dietary polyphenolic plant-derived compounds have anticancer activity. Many laboratories, including ours, have reported such an effect in cancers of the gastrointestinal tract, lung, skin, prostate and breast. The catechins are a group of polyphenols found in green tea, which is one of the most commonly consumed beverages in the world. While the preponderance of the data strongly indicates significant antitumorigenic benefits from the green tea catechins, the potential molecular mechanisms involved remain obscure. We found that green tea components induce apoptosis via a TGF-beta superfamily protein, NAG-1 (Non-steroidal anti-inflammatory drug Activated Gene). In this report, we show that ECG is the strongest NAG-1 inducer among the tested catechins and that treatment of HCT-116 cells results in an increasing G(1) sub-population, and cleavage of poly (ADP-ribose) polymerase ( PARP), consistent with apoptosis. In contrast, other catechins do not significantly induce NAG-1 expression, PARP cleavage or morphological changes at up to a 50-muM concentration. Furthermore, we provide evidence that ECG induces the ATF3 transcription factor, followed by NAG-1 induction at the transcriptional level in a p53-independent manner. The data generated by this study will help elucidate mechanisms of action for components in green tea and this information may lead to the design of more effective anticancer agents and informed clinical trials.

摘要： Hodgkin and Reed-Sternberg (HRS) cells display aberrant activity of several transcription factors, including nuclear factor kappa B (NF-kB) and members of the activator protein-1 (AP-1) family, that promote cytokine expression, cellular survival and proliferation. Using oligonucleotide microarrays, we set out to identify additional factors which are responsible for the malignant phenotype of HRS cells. Microarray analysis and subsequent Northern and Western blotting revealed that activating transcription factor 3 (ATF3), a member of the CREB/ATF family of transcription factors that is involved in the cellular response to stress signals, shows a strong constitutive expression in Hodgkin-derived cell lines. In contrast, ATF3 expression could not be detected in several Non-Hodgkin cell lines of distinct differentiation stages, ranging from pre-B cell lines to plasma B cell lines. To investigate the expression pattern of ATF3 in primary tumor cells, we performed immunohistochemistry on tissue microarrays. Immunohistochemistry confirmed a strong expression of ATF3 in primary HRS cells with a nuclear staining pattern. ATF3 expression was observed in almost all cases of classical Hodgkin lymphoma examined (69/71), whereas ATF3 expression was not detected in lymphocyte-predominant Hodgkin lymphoma. In addition, a significant number of anaplastic large cell lymphomas revealed a nuclear ATF3 staining pattern. In contrast, among all other B and T cell Non-Hodgkin lymphomas, ATF3 expression was observed only in rare cases (7/244), indicating that ATF3 expression is almost exclusively restricted to classical Hodgkin lymphoma and to a subset of anaplastic large cell lymphomas. To investigate the role of ATF3 for proliferation and survival of HRS cells, we generated vector-based siRNA constructs to downregulate ATF3 expression. Our vector system carries a puromycin-resistance gene thus allowing selection of siRNA expressing cells. Transfection of Hodgkin-derived cell lines with AT

关键词： AFP   alpha-fetoprotein   AMACR   methyl-CoA racemase alpha   APC   adenomatous polyposis coli   ATF3   activating transcription factor 3   CCNA2   cyclin A2   CCNG1   cyclin G1   CDK   cyclin-dependent protein kinases   C-FOS   fos proto-oncogene   CHK1   checkpoint kinase-1   COX-2   cyclooxygenase-2   CRC   colorectal cancer   CYP2C9   cytochrome P450 2C9   CYP2C19   cytochrome P450 2C19   CYP2D6   cytochrome P450 2D6   CYP3A4   cytochrome P450 3A4   CYP27B1   cytochrome P450 27B1   MDM2   human mdm2-A   ODC1   ornithine decarboxylase 1   PKCB1   protein kinase C beta 1   PRDX1   peroxiredoxin 1   PTGS2   prostaglandin-endoperoxide synthase 2  

摘要： The evidence from epidemiological and experimental studies that vegetables reduce the risk of colorectal cancer is convincing. However, the involved genes and genetic pathways are not clear. The aim of this study was to identify genes that are modulated in vivo in colorectal mucosa by vegetables, and to investigate whether colon adenoma patients respond differently compared with healthy controls. Twenty female adenoma patients and eight healthy controls were randomly split into two groups of ten and four persons, respectively, receiving either a 50% decreased (=75 g/day) or doubled (=300 g/day) intake of vegetables for 2 weeks. In order to assess the effects on gene expression at the target level, colorectal biopsies were collected before and after the intervention. Total RNA was isolated from the biopsies to measure gene expression of 597 genes relevant for responses to xenobiotics by microarray technology, followed by confidence analyses to identify differentially expressed genes. Mainly genes related to cell cycle control and genes for oxidoreductase activities were over-represented in the list of modulated genes. Twenty genes were modulated, which are known to be related to (colon)carcinogenesis. Seven genes were similarly modulated in patients and controls, for example fos proto-oncogene and ornithine decarboxylase. Thirteen genes were modulated differently in patients compared with controls, including cyclooxygenase-2 and human mdm2-A in patients and cytochrome P45027B1, -2C19, -2D6, -2C9 and -3A4 in controls. Almost all the effects on modulating the expression of genes by altering vegetable intake can be mechanistically linked to cellular processes that explain either prevention of colorectal cancer risk by high vegetable intake or increased colorectal cancer risk by low vegetable intake. Furthermore, it seems that vegetables in patients affect genes involved in the late stage of colorectal cancer, whereas in controls genes involved in the initiation phase ar

关键词： Sciatic Nerve   Schwann Cell   Axonal Regeneration   Wallerian Degeneration   Injured Nerve  

摘要： Background: Many changes in gene expression occur in distal stumps of injured nerves but the transcriptional control of these events is poorly understood. We have examined the expression of the transcription factors ATF3 and c-Jun by non-neuronal cells during Wallerian degeneration following injury to sciatic nerves, dorsal roots and optic nerves of rats and mice, using immunohistochemistry and in situ hybridization. Results: Following sciatic nerve injury-transection or transection and reanastomosis-ATF3 was strongly upregulated by endoneurial, but not perineurial cells, of the distal stumps of the nerves by 1 day post operation (dpo) and remained strongly expressed in the endoneurium at 30 dpo when axonal regeneration was prevented. Most ATF3+ cells were immunoreactive for the Schwann cell marker, S100. When the nerve was transected and reanastomosed, allowing regeneration of axons, most ATF3 expression had been downregulated by 30 dpo. ATF3 expression was weaker in the proximal stumps of the injured nerves than in the distal stumps and present in fewer cells at all times after injury. ATF3 was upregulated by endoneurial cells in the distal stumps of injured neonatal rat sciatic nerves, but more weakly than in adult animals. ATF3 expression in transected sciatic nerves of mice was similar to that in rats. Following dorsal root injury in adult rats, ATF3 was upregulated in the part of the root between the lesion and the spinal cord (containing Schwann cells), beginning at 1 dpo, but not in the dorsal root entry zone or in the degenerating dorsal column of the spinal cord. Following optic nerve crush in adult rats, ATF3 was found in some cells at the injury site and small numbers of cells within the optic nerve displayed weak immunoreactivity. The pattern of expression of c-Jun in all types of nerve injury was similar to that of ATF3. Conclusion: These findings raise the possibility that ATF3/c-Jun heterodimers may play a role in regulating changes in gene expressio

关键词： CGRP   lumbar   P2X3   rat   sciatic  

摘要： Activating transcription factor-3 (ATF3) is a member of the ATF/CREB transcription factor superfamily and is induced in dorsal root ganglion (DRG) cells after nerve injury In order to study the regulation of ATF3, we have examined the effect of nerve growth factor (NGF) and glial cell line-derived neurotrophic factor (GDNF) on ATF3 expression. In untreated rats, sciatic nerve transection induced ATF3 immunoreactivity in 82% of L4 DRG cells at 14 days after axotomy Intrathecal delivery of NGF or GDNF for 2 weeks commencing immediately after injury reduced the ATF3 expression to 35 and 23% of DRG cells, respectively Cell size analysis indicated that NGF had protected a population of mainly small- to medium-sized cells, but that the GDNF had protected a population of both small and large cells. This effect was confirmed by double labelling for P2X(3), CGRP and 200 kDa neurofilament, markers for small peptide-poor cells, peptide-rich cells and large cells, respectively Thus GDNF reduced the percentage of ATF3-immunoreactive P2X(3) cells from 70 to 4%, and the percentage of ATF3-immunoreactive neurofilament cells from 63 to 24%. NGF was less effective than GDNF in reducing ATF3 expression in these cell types, but reduced the percentage of ATF3-immunoreactive CGRP cells from 10% to < 1 %. These results show that ATF3 expression in specific populations of DRG cells can be modulated by exogenous supplementation of specific trophic factors, and suggest that ATF3 expression may normally be induced by the loss of target-derived NGF and GDNF.

关键词： ATF3   activating transcription factor 3   APC   adenomatous polyposis coli   Cox   cyclooxygenase   C/EBPβ   CCAAT/enhancer binding protein-β   FACS   fluorescence-activated cell sorting   NF-κB   nuclear factor-kappa B   FBS   fetal bovine serum   INSIG1   insulin induced gene 1   MSX1   Msh homeo box homolog 1   MAD2   mitotic arrest deficient-like 1   NAG-1   NSAID activated gene-1   NSAIDs   non-steroidal anti-inflammatory drugs   NRG-1   NSAID regulated gene-1   PGE2   prostaglandin E2   RT–PCR   reverse transcription–polymerase chain reaction   TBS-T   Tris-buffered saline Tween-20   VEGF   vascular endothelial growth factor  

摘要： Cox-1 and Cox-2 specific inhibitors exert chemo-preventative activity. However, the exact mechanisms for this activity remain unclear. Increasing evidence suggests that non-steroidal anti-inflammatory drugs regulate gene expression, which may be responsible, in part, for this activity. In this study, human colorectal carcinoma HCT-116 cells were treated with the Cox-1 specific inhibitor SC-560 and the Cox-2 specific inhibitor SC-58125 to evaluate their ability to induce apoptosis, inhibit cell proliferation, inhibit growth on soft agar and modulate gene expression. The Cox-1 specific inhibitor, SC-560 significantly induced apoptosis and inhibited the growth of HCT-116 cells on soft agar, an in vitro assay for tumorigenicity. SC-58125 moderately induced apoptosis and inhibited growth on soft agar at higher concentrations than were required for SC-560. Previously, we reported that the potent chemo-preventative drug sulindac sulfide altered the expression of eight genes including several transcription factors that may be linked to this drug's chemo-preventative activity. HCT-116 cells were treated with various concentrations of SC-560 or SC-58125 and changes in the expression of these eight genes were determined by real-time reverse transcription- polymerase chain reaction. SC-560 modulated mRNA expression of the eight genes studied. In contrast, SC-58125 required similar to5-10-fold higher concentrations to achieve similar degrees of gene modulation in six of eight genes. Changes in protein expression by SC-560 also occurred for five of these genes with antibodies available (NAG-1, ATF3, C/EBPbeta, MAD2 and MSX1). In conclusion, this is the first report to suggest that like sulindac sulfide, the Cox-1 specific inhibitor SC-560 appears to elicit chemo-preventative activity by altering gene expression, while the chemo-preventative effects of SC-58125 are complex and probably work through these and other mechanisms, such as the inhibition of Cox-2.