scholarly journals The activating transcription factor 2: an influencer of cancer progression

Mutagenesis ◽  
2019 ◽  
Vol 34 (5-6) ◽  
pp. 375-389 ◽  
Author(s):  
Kerstin Huebner ◽  
Jan Procházka ◽  
Ana C Monteiro ◽  
Vijayalakshmi Mahadevan ◽  
Regine Schneider-Stock
Keyword(s):  
Pancreatic Cancer ◽  
Transcription Factor ◽  
3D Structure ◽  
Genetic Alterations ◽  
Tumour Suppressor Genes ◽  
Subcellular Localisation ◽  
Dependent Manner ◽  
Continuous Increase ◽  
Mesenchymal Transition ◽  
Activating Transcription Factor

Abstract In contrast to the continuous increase in survival rates for many cancer entities, colorectal cancer (CRC) and pancreatic cancer are predicted to be ranked among the top 3 cancer-related deaths in the European Union by 2025. Especially, fighting metastasis still constitutes an obstacle to be overcome in CRC and pancreatic cancer. As described by Fearon and Vogelstein, the development of CRC is based on sequential mutations leading to the activation of proto-oncogenes and the inactivation of tumour suppressor genes. In pancreatic cancer, genetic alterations also attribute to tumour development and progression. Recent findings have identified new potentially important transcription factors in CRC, among those the activating transcription factor 2 (ATF2). ATF2 is a basic leucine zipper protein and is involved in physiological and developmental processes, as well as in tumorigenesis. The mutation burden of ATF2 in CRC and pancreatic cancer is rather negligible; however, previous studies in other tumours indicated that ATF2 expression level and subcellular localisation impact tumour progression and patient prognosis. In a tissue- and stimulus-dependent manner, ATF2 is activated by upstream kinases, dimerises and induces target gene expression. Dependent on its dimerisation partner, ATF2 homodimers or heterodimers bind to cAMP-response elements or activator protein 1 consensus motifs. Pioneering work has been performed in melanoma in which the dual role of ATF2 is best understood. Even though there is increasing interest in ATF2 recently, only little is known about its involvement in CRC and pancreatic cancer. In this review, we summarise the current understanding of the underestimated ‘cancer gene chameleon’ ATF2 in apoptosis, epithelial-to-mesenchymal transition and microRNA regulation and highlight its functions in CRC and pancreatic cancer. We further provide a novel ATF2 3D structure with key phosphorylation sites and an updated overview of all so-far available mouse models to study ATF2 in vivo.

Abstract 16440: Cu Transporter ATP7A Protects Against Fibrosis Through Limiting Endothelial to Mesenchymal Transition

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Seock-Won Youn ◽  
Sudhahar Varadarajan ◽  
Archita Das ◽  
Ronald D McKinney ◽  
Tohru Fukai ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Inflammatory Diseases ◽  
Shape Change ◽  
Atherosclerotic Lesion ◽  
Transport Proteins ◽  
Dependent Manner ◽  
Mesenchymal Transition ◽  
Endothelial To Mesenchymal Transition

Background: Endothelial to mesenchymal transition (EndMT) is induced by inflammation and contributes to fibrosis; however, underlying mechanism is poorly understood. Cu plays an important role in physiological processes and pathophysiologies associated with inflammatory diseases. Since excess Cu is toxic, bioavailability of Cu is tightly controlled by Cu exporter ATP7A, which obtains Cu via Cu chaperone, Atox1, and exclude Cu. We reported that Atox1 also functions as a Cu dependent transcription factor. However, role of Cu transport proteins in EndMT is entirely unknown.[[Unable to Display Character: 
]] Results: Here we show that TNFα stimulation for 24hr in HUVEC significantly decreased ATP7A protein (80%) and increased intracellular Cu and Atox1 in nucleus, which was associated with shape change forming EndMT. ATP7A depletion with shRNA in EC significantly reduced EC markers (VE-cadherin and VEGFR2) and increased mesenchymal markers (αSMA, Calponin, SM22α, Collagen I/II). ATP7A siRNA also increased intracellular Cu and nuclear Atox1. These ATP7A knockdown-induced phenotype changes were inhibited by Cu chelators BCS and TTM. Mechanistically, microarray and qPCR based screening revealed that ATP7A knockdown in EC significantly increased miR21 (2.5 fold) and miR125b (1.5 fold) which induce EndMT in a Cu-dependent manner. Of note, promoters of both miR21 and miR125b have Cu dependent transcription factor Atox1 binding sites. Consistent with this, overexpression of Atox1 increased miR21 and miR125b expression as well as promoted EndMT. In vivo, ATP7A mutant (ATP7Amut) mice with reduced Cu export function showed impaired blood flow recovery and reduced arteriogenesis while increased αSMA+ cells and fibrosis in capillary network after ischemic injury. Moreover, ATP7Amut mice crossed with ApoE-/- mice with high fat diet (HFD) induced robust fibrosis and enhanced atherosclerotic lesion vs ApoE-/-/HFD mice.[[Unable to Display Character: 
]] Conclusions: ATP7A protects against fibrosis by preventing EndMT via nuclear Atox1-mediated upregulation of miR21 and miR125b which induce EndMT, in Cu dependent manner. These findings provide the foundation for novel protective role of Cu transport proteins against EndMT- and fibrosis-mediated cardiovascular diseases.

scholarly journals Concomitant Nrf2- and ATF4-activation by Carnosic Acid Cooperatively Induces Expression of Cytoprotective Genes

2019 ◽  
Vol 20 (7) ◽  
pp. 1706 ◽  
Author(s):  
Junsei Mimura ◽  
Atsushi Inose-Maruyama ◽  
Shusuke Taniuchi ◽  
Kunio Kosaka ◽  
Hidemi Yoshida ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Carnosic Acid ◽  
Related Factor ◽  
Dependent Manner ◽  
Independent Manner ◽  
Antioxidant Genes ◽  
Activating Transcription Factor 4 ◽  
Activating Transcription Factor ◽  
Rosmarinus Officinalis L ◽  
Ngf Gene

: Carnosic acid (CA) is a phytochemical found in some dietary herbs, such as Rosmarinus officinalis L., and possesses antioxidative and anti-microbial properties. We previously demonstrated that CA functions as an activator of nuclear factor, erythroid 2 (NF-E2)-related factor 2 (Nrf2), an oxidative stress-responsive transcription factor in human and rodent cells. CA enhances the expression of nerve growth factor (NGF) and antioxidant genes, such as HO-1 in an Nrf2-dependent manner in U373MG human astrocytoma cells. However, CA also induces NGF gene expression in an Nrf2-independent manner, since 50 μM of CA administration showed striking NGF gene induction compared with the classical Nrf2 inducer tert-butylhydroquinone (tBHQ) in U373MG cells. By comparative transcriptome analysis, we found that CA activates activating transcription factor 4 (ATF4) in addition to Nrf2 at high doses. CA activated ATF4 in phospho-eIF2α- and heme-regulated inhibitor kinase (HRI)-dependent manners, indicating that CA activates ATF4 through the integrated stress response (ISR) pathway. Furthermore, CA activated Nrf2 and ATF4 cooperatively enhanced the expression of NGF and many antioxidant genes while acting independently to certain client genes. Taken together, these results represent a novel mechanism of CA-mediated gene regulation evoked by Nrf2 and ATF4 cooperation.

Transcriptional regulation of endothelial-to-mesenchymal transition in cardiac fibrosis: role of myocardin-related transcription factor A and activating transcription factor 3

2017 ◽  
Vol 95 (10) ◽  
pp. 1263-1270 ◽  
Author(s):  
Vibhuti Sharma ◽  
Nilambra Dogra ◽  
Uma Nahar Saikia ◽  
Madhu Khullar
Keyword(s):  
Endothelial Cells ◽  
Transcription Factor ◽  
Cardiac Fibrosis ◽  
Activating Transcription Factor 3 ◽  
Mesenchymal Transition ◽  
Related Transcription Factor ◽  
Endothelial To Mesenchymal Transition ◽  
Activating Transcription Factor ◽  
Transcription Factor 3

The etiology of cardiac fibrogenesis is quite diverse, but a common feature is the presence of activated fibroblasts. Experimental evidence suggests that a subset of cardiac fibroblasts is derived via transition of vascular endothelial cells into fibroblasts by endothelial-to-mesenchymal transition (EndMT). During EndMT, endothelial cells lose their endothelial characteristics and acquire a mesenchymal phenotype. Molecular mechanisms and the transcriptional mediators controlling EndMT in heart during development or disease remain relatively undefined. Myocardin-related transcription factor A facilitates the transcription of cytoskeletal genes by serum response factor during fibrosis; therefore, its specific role in cardiac EndMT might be of importance. Activation of activating transcription factor 3 (ATF-3) during cardiac EndMT is speculative, since ATF-3 responds to a transforming growth factor β (TGF-β) stimulus and controls the expression of the primary epithelial-to-mesenchymal transition markers Snail, Slug, and Twist. Although the role of TGF-β in EndMT-mediated cardiac fibrosis has been established, targeting of the TGF-β ligand has not proven to be a viable anti-fibrotic strategy owing to the broad functional importance of this ligand. Thus, targeting of downstream transcriptional mediators may be a useful therapeutic approach in attenuating cardiac fibrosis. Here, we discuss some of the transcription factors that may regulate EndMT-mediated cardiac fibrosis and their involvement in type 2 diabetes.

scholarly journals Up-Regulated ATF4 Expression Increases Cell Sensitivity to Apoptosis in Response to Radiation

2017 ◽  
Vol 41 (2) ◽  
pp. 784-794 ◽  
Author(s):  
Ying Zong ◽  
Shijie Feng ◽  
Jinwei Cheng ◽  
Chenlin Yu ◽  
Guocai Lu
Keyword(s):  
Cell Proliferation ◽  
Transcription Factor ◽  
Cell Apoptosis ◽  
Hek293 Cells ◽  
Cell Counting ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Over Expression ◽  
Radiation Induced ◽  
Activating Transcription Factor

Background/Aims: Activating transcription factor 4 (ATF4) is a member of the activating transcription factor family which regulates the expression of genes involved in amino acid metabolism, redox homeostasis and ER stress responses. ATF4 is also over-expressed in human solid tumors, although its effect on responsiveness to radiation is largely unexplored. Methods: Real-time PCR was used to detect ATF4 mRNA levels in cells treated with different doses of 60Coγ radiation. Cell viability was assayed using a cell counting kit. The cell cycle was analyzed using flow cytometry, and cell apoptosis was assayed using Annexin V-PI double labeling. Small interfering RNA (siRNA) against ATF4 was transfected into ECV304 cells using Lipofectamine 2000. An ATF4 over-expression plasmid (p-ATF4-CGN) was transfected into HEK293 cells that endogenously expressed low levels of ATF4. The levels of intracellular reactive oxygen species (ROS) were measured using CM-H2DCFDA as a probe. Results: ATF4 mRNA and protein expression levels were higher after radiation and increased in a dose- and time-dependent manner in AHH1 lymphoblast cells (P < 0.05). An increase in ATF4 levels was also observed after radiation in primary murine spleen cells, human endothelial ECV304 cells, human liver LO2 cells, breast cancer MCF7 cells, and human hepatocellular carcinoma HEPG2 cells. No change was observed in human embryonic kidney 293 (HEK293) cells. Over-expressing ATF4 in HEK293 cells inhibited cell proliferation, increased cell apoptosis and significantly increased the proportion of cells in G1 phase. Conversely, when ATF4 expression was knocked down using siRNA in ECV304 cells, it protected the cells from radiation-induced apoptosis. These findings suggest that ATF4 may play a role in radiation-induced cell killing by inhibiting cell proliferation and promoting cell apoptosis. Conclusions: In this study, we found that radiation up-regulated the expression of ATF4. We used ATF4 knockdown and over-expression systems to show that ATF4 may play a role in radiation-induced cellular apoptosis.

scholarly journals Molecular Events in Primary and Metastatic Colorectal Carcinoma: A Review

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Rani Kanthan ◽  
Jenna-Lynn Senger ◽  
Selliah Chandra Kanthan
Keyword(s):  
Colorectal Carcinoma ◽  
Epithelial Mesenchymal Transition ◽  
Cpg Island ◽  
Genetic Alterations ◽  
Tumour Suppressor Genes ◽  
Metastatic Colorectal Carcinoma ◽  
Cpg Island Methylator Phenotype ◽  
Mesenchymal Transition ◽  
Sequence Of Events ◽  
Molecular Events

Colorectal cancer (CRC) is a heterogeneous disease, developing through a multipathway sequence of events guided by clonal selections. Pathways included in the development of CRC may be broadly categorized into (a) genomic instability, including chromosomal instability (CIN), microsatellite instability (MSI), and CpG island methylator phenotype (CIMP), (b) genomic mutations including suppression of tumour suppressor genes and activation of tumour oncogenes, (c) microRNA, and (d) epigenetic changes. As cancer becomes more advanced, invasion and metastases are facilitated through the epithelial-mesenchymal transition (EMT), with additional genetic alterations. Despite ongoing identification of genetic and epigenetic markers and the understanding of alternative pathways involved in the development and progression of this disease, CRC remains the second highest cause of malignancy-related mortality in Canada. The molecular events that underlie the tumorigenesis of primary and metastatic colorectal carcinoma are detailed in this manuscript.

scholarly journals Parathyroid Hormone Increases Activating Transcription Factor 4 Expression and Activity in Osteoblasts: Requirement for Osteocalcin Gene Expression

Endocrinology ◽  
2008 ◽  
Vol 149 (4) ◽  
pp. 1960-1968 ◽  
Author(s):  
Shibing Yu ◽  
Renny T. Franceschi ◽  
Min Luo ◽  
Xiaoyan Zhang ◽  
Di Jiang ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Protein Kinase ◽  
Transcriptional Activity ◽  
De Novo ◽  
Dependent Manner ◽  
Specific Element ◽  
Activating Transcription Factor 4 ◽  
Activating Transcription Factor ◽  
Transcription Factor 4 ◽  
Expression And Activity

PTH is an important peptide hormone regulator of calcium homeostasis and osteoblast function. However, its mechanism of action in osteoblasts is poorly understood. Our previous study demonstrated that PTH activates mouse osteocalcin (Ocn) gene 2 promoter through the osteoblast-specific element 1 site, a recently identified activating transcription factor-4 (ATF4) -binding element. In the present study, we examined effects of PTH on ATF4 expression and activity as well as the requirement for ATF4 in the regulation of Ocn by PTH. Results show that PTH elevated levels of ATF4 mRNA and protein in a dose- and time-dependent manner. This PTH regulation requires transcriptional activity but not de novo protein synthesis. PTH also increased binding of nuclear extracts to osteoblast-specific element 1 DNA. PTH stimulated ATF4-dependent transcriptional activity mainly through protein kinase A with a lesser requirement for protein kinase C and MAPK/ERK pathways. Lastly, PTH stimulation of Ocn expression was lost by small interfering RNA down-regulation of ATF4 in MC-4 cells and Atf4−/− bone marrow stromal cells. Collectively, these studies for the first time demonstrate that PTH increases ATF4 expression and activity and that ATF4 is required for PTH induction of Ocn expression in osteoblasts.

scholarly journals The mitochondria mediate the induction of NOX1 gene expression by aldosterone in an ATF-1-dependent manner

2011 ◽  
Vol 16 (2) ◽  
Author(s):  
Yanping Fu ◽  
Gang Shi ◽  
Yong Wu ◽  
Yasuyuki Kawai ◽  
Qing Tian ◽  
...  
Keyword(s):  
Gene Expression ◽  
Heart Failure ◽  
Transcription Factor ◽  
Smooth Muscle ◽  
Complex I ◽  
Mitochondrial Respiratory Chain ◽  
Dependent Manner ◽  
Over Expression ◽  
Diphenylene Iodonium ◽  
Activating Transcription Factor

AbstractHigh aldosterone (Ald) levels can induce hypertrophy of vascular smooth muscle cells (VSMCs), which carries high risks of heart failure. A previous study showed that Ald induces hypertrophy of VSMCs by up-regulating NOX1, a catalytic subunit of NADPH oxidase that produces superoxides. However, the precise mechanism remains unknown. Diphenylene iodonium (DPI) is known as an inhibitor of complex I in the mitochondrial respiratory chain, and it was also found to almost completely suppress the induction of NOX1 mRNA and the phosphorylation of activating transcription factor (ATF-1) by PGF2α or PDGF in a rat VSMC cell line. In this study, we found that the Ald-induced phosphorylation of ATF-1 and NOX1 expression was significantly suppressed by DPI. Silencing of ATF-1 gene expression attenuated the induction of NOX1 mRNA expression, and over-expression of ATF-1 restored Ald-induced NOX1 expression. On the basis of this data, we show that the mitochondria mediate aldosterone-induced NOX1 gene expression in an ATF-1-dependent manner.

scholarly journals The BHLH transcription factor DEC1 plays an important role in the epithelial-mesenchymal transition of pancreatic cancer

2012 ◽  
Vol 41 (4) ◽  
pp. 1337-1346 ◽  
Author(s):  
YUNYAN WU ◽  
FUYUKI SATO ◽  
TOSHIYUKI YAMADA ◽  
UJJAL KUMAR BHAWAL ◽  
TAKESHI KAWAMOTO ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Transcription Factor ◽  
Epithelial Mesenchymal Transition ◽  
Bhlh Transcription Factor ◽  
Mesenchymal Transition

scholarly journals Epithelial Transcription Factor FOXA1 Regulates Prostate Cancer Immune Response

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A1017-A1017
Author(s):  
Lourdes T Brea ◽  
Xiaohai Wang ◽  
Jindan Yu
Keyword(s):  
Prostate Cancer ◽  
Immune Response ◽  
Transcription Factor ◽  
Inflammatory Response ◽  
Epithelial Mesenchymal Transition ◽  
Checkpoint Inhibitors ◽  
Macrophage Infiltration ◽  
Dependent Manner ◽  
Rna Seq ◽  
Mesenchymal Transition

Abstract Background : While localized prostate cancer (PCa) can be mitigated by surgery and radiation, metastatic PCa remains a challenge to treat. Androgen deprivation therapies and androgen receptor (AR) pathway inhibitors are mainstay treatments for advanced PCa. Yet, resistance often develops leading to castration-resistant prostate cancer (CRPC). Forkhead Box A1 (FOXA1) is a pioneer transcription factor that plays pivotal roles in regulating AR activity and promoting epithelial differentiation. Studies have shown that FOXA1 is frequently downregulated in CRPC tumors. Congruently, FOXA1 loss is reported to induce aberrant AR signaling, epithelial-mesenchymal transition, and PCa de-differentiation. However, the role of FOXA1 in regulating PCa immune response, an area of much interest recently, has not been reported. CRPC has shown poor response to immune checkpoint inhibitors, due to its immunosuppressive nature. A better understanding of the tumor intrinsic mechanisms regulating PCa tumor immunity will inform the design of better targeted immunotherapeutic approaches. Methods: We performed RNA-seq, ChIP-seq, qPCR, western blot, and ELISA analyses to evaluate how FOXA1 regulates inflammatory response genes. We utilized an in vitro macrophage infiltration transwell assay, in which M2-like macrophages were added to the upper chamber and PCa cells were plated in the lower chamber, to examine how perturbations to PCa cells affect macrophage migration. Finally, we performed bioinformatic analyses of patient datasets to confirm the clinical relevance of FOXA1 repression of inflammatory genes in PCa. Results: Through integration of RNA-seq and ChIP-seq data, we uncovered a novel function of FOXA1 in suppressing inflammatory response pathways. In accordance, patient data analyses revealed that inflammatory response genes were upregulated in FOXA1-low PCa tumors. Mechanistically, we showed that FOXA1 proteins bound an intragenic enhancer of Hypoxia-inducible factor 1-alpha (HIF1A) gene to directly repress its expression, such that FOXA1 loss induced HIF1A upregulation. We further showed that Monocyte Chemoattractant Protein-1 (MCP-1/CCL2) became upregulated upon FOXA1 depletion in a HIF1A-dependent manner. This led to infiltration by immunosuppressive, tumor promoting M2-like macrophages. Inhibiting this HIF1A-CCL2 axis with a HIF1A inhibitor or CCL2 neutralizing antibody blocked macrophage infiltration. Future studies using immunocompetent mouse models are needed to confirm the effect of FOXA1 on macrophage infiltration in vivo and evaluate the preclinical potential of targeting the FOXA1-HIF1A-CCL2 axis in CRPC. Conclusion: This study proposes a novel role for FOXA1 loss in promoting macrophage infiltration via the HIF1A-CCL2 axis. Moreover, our findings suggest that targeting this axis may be a promising approach for the treatment of FOXA1-low CRPC tumors.

scholarly journals miR-9-5p Exerts a Dual Role in Cervical Cancer and Targets Transcription Factor TWIST1

Cells ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 65 ◽  
Author(s):  
Iris Babion ◽  
Annelieke Jaspers ◽  
Annina P. van Splunter ◽  
Iris A.E. van der Hoorn ◽  
Saskia M. Wilting ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Transcription Factor ◽  
Cell Lines ◽  
Epithelial To Mesenchymal Transition ◽  
Dual Role ◽  
Dependent Manner ◽  
Tissue Samples ◽  
Mesenchymal Transition ◽  
High Risk Hpv ◽  
Hrhpv Type

Squamous cell carcinoma (SCC) and adenocarcinoma (AC) represent the major cervical cancer histotypes. Both histotypes are caused by infection with high-risk HPV (hrHPV) and are associated with deregulated microRNA expression. Histotype-dependent expression has been observed for miR-9-5p, showing increased expression in SCC and low expression in AC. Here, we studied the regulation and functionality of miR-9-5p in cervical SCCs and ACs using cervical tissue samples and hrHPV-containing cell lines. Expression and methylation analysis of cervical tissues revealed that low levels of miR-9-5p in ACs are linked to methylation of its precursor genes, particularly miR-9-1. Stratification of tissue samples and hrHPV-containing cell lines suggested that miR-9-5p depends on both histotype and hrHPV type, with higher expression in SCCs and HPV16-positive cells. MiR-9-5p promoted cell viability and anchorage independence in cervical cancer cell lines SiHa (SCC, HPV16) and CaSki (metastasized SCC, HPV16), while it played a tumor suppressive role in HeLa (AC, HPV18). TWIST1, a transcription factor involved in epithelial-to-mesenchymal transition (EMT), was established as a novel miR-9-5p target. Our results show that miR-9-5p plays a dual role in cervical cancer in a histotype- and hrHPV type-dependent manner. MiR-9-5p mediated silencing of TWIST1 suggests two distinct mechanisms towards EMT in cervical cancer.

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