Scan Science and Technology
Contact Leading Edge Experts & Companies
The Experts below are selected from a list of 31395 Experts worldwide ranked by ideXlab platform
Tsonwin Hai – One of the best experts on this subject based on the ideXlab platform.
ATF3 deficiency promotes genome instability and spontaneous tumorigenesis in miceOncogene, 2017Co-Authors: Ziyan Wang, W. Deng, L. Lang, H. Yang, B. Jin, Ravindra Kolhe, Han-fei Ding, Junran Zhang, Tsonwin HaiAbstract:
Mice lacking genes involving in the DNA-damage response (DDR) are often tumor prone owing to genome instability caused by oncogenic challenges. Previous studies demonstrate that activating transcription factor 3 (ATF3), a common stress sensor, can activate the tumor suppressor p53 and regulate expression of p53 target genes upon DNA damage. However, whether ATF3 contributes to the maintenance of genome stability and tumor suppression remains unknown. Here we report that ATF3-deficient (ATF3-/-) mice developed spontaneous tumors, and died significantly earlier than wild-type (ATF3+/+) mice. Consistent with these results, ATF3-/- mouse embryonic fibroblasts (MEFs) had more aberrant chromosomes and micronuclei, and were genetically unstable. Whereas we demonstrated that ATF3 activated p53 and promoted its pro-apoptotic activity in mouse thymi and small intestines, the chromosomal instability caused by ATF3 deficiency was largely dependent on the regulation of p53 by ATF3. Interestingly, loss of ATF3 also promoted spontaneous tumorigenesis in Trp53+/- mice, but did not affect tumor formation in Trp53-/- mice. Our results thus provide the first genetic evidence linking ATF3 to the suppression of the early development of cancer, and underscore the importance of ATF3 in the maintenance of genome integrity.
Loss of ATF3 promotes Akt activation and prostate cancer development in a Pten knockout mouse model.Oncogene, 2014Co-Authors: Ziyan Wang, Tsonwin Hai, Han-fei Ding, Junran Zhang, Jaejik Kim, Chunhong YanAbstract:
Activating transcription factor 3 (ATF3) responds to diverse cellular stresses, and regulates oncogenic activities (for example, proliferation, survival and migration) through direct transcriptional regulation or protein-protein interactions. Although aberrant ATF3 expression is frequently found in human cancers, the role of ATF3 in tumorigenesis is poorly understood. Here, we demonstrate that ATF3 suppresses the development of prostate cancer induced by knockout of the tumor suppressor Pten in mouse prostates. Whereas the oncogenic stress elicited by Pten loss induced ATF3 expression in prostate epithelium, we found that ATF3 deficiency increased cell proliferation and promoted cell survival, leading to early onset of mouse prostatic intraepithelial neoplasia and the progression of prostate lesions to invasive adenocarcinoma. Importantly, the loss of ATF3 promoted activation of the oncogenic AKT signaling evidenced by high levels of phosphorylated AKT and S6 proteins in ATF3-null prostate lesions. In line with these in vivo results, knockdown of ATF3 expression in human prostate cancer cells by single guided RNA-mediated targeting activated AKT and increased matrix metalloproteinase-9 expression. Our results thus link ATF3 to the AKT signaling, and suggest that ATF3 is a tumor suppressor for the major subset of prostate cancers harboring dysfunctional Pten.
ATF3 is a novel regulator of mouse neutrophil migrationBlood, 2014Co-Authors: Nicholas D. Boespflug, Tsonwin Hai, Sachin Kumar, Jaclyn W. Mcalees, James D. Phelan, H. Leighton Grimes, Kasper Hoebe, Marie-dominique Filippi, Christopher L. KarpAbstract:
Expression of the activating transcription factor 3 (ATF3) gene is induced by Toll-like receptor (TLR) signaling. In turn, ATF3 protein inhibits the expression of various TLR-driven proinflammatory genes. Given its counter-regulatory role in diverse innate immune responses, we defined the effects of ATF3 on neutrophilic airway inflammation in mice. ATF3 deletion was associated with increased lipopolysaccharide (LPS)-driven airway epithelia production of CXCL1, but not CXCL2, findings concordant with a consensus ATF3-binding site identified solely in the Cxcl1 promoter. Unexpectedly, ATF3-deficient mice did not exhibit increased airway neutrophilia after LPS challenge. Bone marrow chimeras revealed a specific reduction in ATF3−/− neutrophil recruitment to wild-type lungs. In vitro, ATF3−/− neutrophils exhibited a profound chemotaxis defect. Global gene expression analysis identified ablated Tiam2 expression in ATF3−/− neutrophils. TIAM2 regulates cellular motility by activating Rac1-mediated focal adhesion disassembly. Notably, ATF3−/− and ATF3-sufficient TIAM2 knockdown neutrophils, both lacking TIAM2, exhibited increased focal complex area, along with excessive CD11b-mediated F-actin polymerization. Together, our data describe a dichotomous role for ATF3-mediated regulation of neutrophilic responses: inhibition of neutrophil chemokine production but promotion of neutrophil chemotaxis.
Chunhong Yan – One of the best experts on this subject based on the ideXlab platform.
The common stress responsive transcription factor ATF3 binds genomic sites enriched with p300 and H3K27ac for transcriptional regulationBMC Genomics, 2016Co-Authors: Jonathan Zhao, Xingyao Li, Mingxiong Guo, Jindan Yu, Chunhong YanAbstract:
BackgroundDysregulation of the common stress responsive transcription factor ATF3 has been causally linked to many important human diseases such as cancer, atherosclerosis, infections, and hypospadias. Although it is believed that the ATF3 transcription activity is central to its cellular functions, how ATF3 regulates gene expression remains largely unknown. Here, we employed ATF3 wild-type and knockout isogenic cell lines to carry out the first comprehensive analysis of global ATF3-binding profiles in the human genome under basal and stressed (DNA damage) conditions.ResultsAlthough expressed at a low basal level, ATF3 was found to bind a large number of genomic sites that are often associated with genes involved in cellular stress responses. Interestingly, ATF3 appears to bind a large portion of genomic sites distal to transcription start sites and enriched with p300 and H3K27ac. Global gene expression profiling analysis indicates that genes proximal to these genomic sites were often regulated by ATF3. While DNA damage elicited by camptothecin dramatically altered the ATF3 binding profile, most of the genes regulated by ATF3 upon DNA damage were pre-bound by ATF3 before the stress. Moreover, we demonstrated that ATF3 was co-localized with the major stress responder p53 at genomic sites, thereby collaborating with p53 to regulate p53 target gene expression upon DNA damage.ConclusionsThese results suggest that ATF3 likely bookmarks genomic sites and interacts with other transcription regulators to control gene expression.
the common stress responsive transcription factor ATF3 binds genomic sites enriched with p300 and h3k27ac for transcriptional regulationBMC Genomics, 2016Co-Authors: Jonathan C Zhao, Chunhong Yan, Mingxiong GuoAbstract:
Dysregulation of the common stress responsive transcription factor ATF3 has been causally linked to many important human diseases such as cancer, atherosclerosis, infections, and hypospadias. Although it is believed that the ATF3 transcription activity is central to its cellular functions, how ATF3 regulates gene expression remains largely unknown. Here, we employed ATF3 wild-type and knockout isogenic cell lines to carry out the first comprehensive analysis of global ATF3-binding profiles in the human genome under basal and stressed (DNA damage) conditions. Although expressed at a low basal level, ATF3 was found to bind a large number of genomic sites that are often associated with genes involved in cellular stress responses. Interestingly, ATF3 appears to bind a large portion of genomic sites distal to transcription start sites and enriched with p300 and H3K27ac. Global gene expression profiling analysis indicates that genes proximal to these genomic sites were often regulated by ATF3. While DNA damage elicited by camptothecin dramatically altered the ATF3 binding profile, most of the genes regulated by ATF3 upon DNA damage were pre-bound by ATF3 before the stress. Moreover, we demonstrated that ATF3 was co-localized with the major stress responder p53 at genomic sites, thereby collaborating with p53 to regulate p53 target gene expression upon DNA damage. These results suggest that ATF3 likely bookmarks genomic sites and interacts with other transcription regulators to control gene expression.
The Stress-responsive Gene ATF3 Mediates Dichotomous UV Responses by Regulating the Tip60 and p53 Proteins.Journal of Biological Chemistry, 2016Co-Authors: Hongmei Cui, Han-fei Ding, Junran Zhang, Chunhua Han, Qi-en Wang, Hongbo Wang, Chunhong YanAbstract:
The response to UV irradiation is important for a cell to maintain its genetic integrity when challenged by environmental genotoxins. An immediate early response to UV irradiation is the rapid induction of activating transcription factor 3 (ATF3) expression. Although emerging evidence has linked ATF3 to stress pathways regulated by the tumor suppressor p53 and the histone acetyltransferase Tip60, the role of ATF3 in the UV response remains largely unclear. Here, we report that ATF3 mediated dichotomous UV responses. Although UV irradiation enhanced the binding of ATF3 to Tip60, knockdown of ATF3 expression decreased Tip60 stability, thereby impairing Tip60 induction by UV irradiation. In line with the role of Tip60 in mediating UV-induced apoptosis, ATF3 promoted the death of p53-defective cells in response to UV irradiation. However, ATF3 could also activate p53 and promote p53-mediated DNA repair, mainly through altering histone modifications that could facilitate recruitment of DNA repair proteins (such as DDB2) to damaged DNA sites. As a result, ATF3 rather protected the p53 wild-type cells from UV-induced apoptosis. Our results thus indicate that ATF3 regulates cell fates upon UV irradiation in a p53-dependent manner.
Shigetaka Kitajima – One of the best experts on this subject based on the ideXlab platform.
ATF3 deficiency in chondrocytes alleviates osteoarthritis development.The Journal of Pathology, 2016Co-Authors: Takashi Iezaki, Shigetaka Kitajima, Makoto Inoue, Kakeru Ozaki, Kazuya Fukasawa, Takeshi Muneta, Shu Takeda, Hiroyuki Fujita, Yuki Onishi, Tetsuhiro HorieAbstract:
Activating transcription factor 3 (ATF3) has been implicated in the pathogenesis of various diseases, including cancer and inflammation, as well as in the regulation of cell proliferation and differentiation. However, the involvement of ATF3 in developmental skeletogenesis and joint disease has not been well studied to date. Here, we show that ATF3 is a critical mediator of osteoarthritis (OA) development through its expression in chondrocytes. ATF3 expression was markedly up-regulated in the OA cartilage of both mice and humans. Conditional deletion of ATF3 in chondrocytes did not result in skeletal abnormalities or affect the chondrogenesis, but alleviated the development of OA generated by surgically inducing knee joint instability in mice. Inflammatory cytokines significantly up-regulated ATF3 expression through the nuclear factor-kB (NF-kB) pathway, while cytokine-induced interleukin-6 (Il6) expression was repressed, in ATF3-deleted murine and human chondrocytes. Mechanistically, ATF3 deficiency decreased cytokine-induced Il6 transcription in chondrocytes through repressing NF-kB signalling by the attenuation of the phosphorylation status of IkB and p65. These findings suggest that ATF3 is implicated in the pathogenesis of OA through modulation of inflammatory cytokine expression in chondrocytes, and the feed-forward loop of inflammatory cytokines/NF-kB/ATF3 in chondrocytes may be a novel therapeutic target for the treatment for OA. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
role of activating transcription factor 3 ATF3 in endoplasmic reticulum er stress induced sensitization of p53 deficient human colon cancer cells to tumor necrosis factor tnf related apoptosis inducing ligand trail mediated apoptosis through up regulJournal of Biological Chemistry, 2014Co-Authors: Makoto Edagawa, Hiroto Goshima, Makoto Inoue, Junya Kawauchi, Manabu Hirata, Tatsuro Okamoto, Akira Murakami, Yoshihiko Maehara, Shigetaka KitajimaAbstract:
Death receptor 5 (DR5) is a death domain-containing transmembrane receptor that triggers cell death upon binding to its ligand, TNF-related apoptosis-inducing ligand (TRAIL), and a combination of TRAIL and agents that increase the expression of DR5 is expected to be a novel anticancer therapy. In this report, we demonstrate that the stress response gene ATF3 is required for endoplasmic reticulum stress-mediated DR5 induction upon zerumbone (ZER) and celecoxib (CCB) in human p53-deficient colorectal cancer cells. Both agents activated PERK-eIF2α kinases and induced the expression of activating transcription factor 4 (ATF4)-CCAAT enhancer-binding protein (C/EBP) homologous protein, which were remarkably suppressed by reactive oxygen species scavengers. In the absence of ATF3, the induction of DR5 mRNA and protein was abrogated significantly, and this was associated with reduced cell death by cotreatment of TRAIL with ZER or CCB. By contrast, exogenous expression of ATF3 caused a more rapid and elevated expression of DR5, resulting in enhanced sensitivity to apoptotic cell death by TRAIL/ZER or TRAIL/CCB. A reporter assay demonstrated that at least two ATF/cAMP response element motifs as well as C/EBP homologous protein motif at the proximal region of the human DR5 gene promoter were required for ZER-induced DR5 gene transcription. Taken together, our results provide novel insights into the role of ATF3 as an essential transcription factor for p53-independent DR5 induction upon both ZER and CCB treatment, and this may be a useful biomarker for TRAIL-based anticancer therapy.
role of ATF3 in synergistic cancer cell killing by a combination of hdac inhibitors and agonistic anti dr5 antibody through er stress in human colon cancer cellsBiochemical and Biophysical Research Communications, 2014Co-Authors: Jia Liu, Makoto Edagawa, Hiroto Goshima, Makoto Inoue, Hideo Yagita, Zhonghui Liu, Shigetaka KitajimaAbstract:
Histone deacetylase inhibitors (HDACIs) are promising agents for cancer therapy. However, the mechanism(s) responsible for the efficacy of HDACIs have not yet to be fully elucidated. Death receptor 5 (DR5) is a transmembrane receptor containing death domain that triggers cell death upon binding to TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) or agonistic anti-DR5 monoclonal antibody, and the combination of TRAIL/agonistic anti-DR5 monoclonal antibody and agents that increase the expression of DR5 is expected as a novel anticancer therapeutic strategy. Here we report that six different HDACIs activated endoplasmic reticulum (ER) stress sensor PERK and eIF2α and induced the ATF4/ATF3/CHOP pathway in p53-deficient human colon cancer cells. This resulted in an increased expression of DR5 on the cell surface and sensitized cells to apoptosis by agonistic anti-DR5 monoclonal antibody. Stress response gene ATF3 was required for efficient DR5 induction by HDACIs, and DR5 reporter assay showed that ATF3 play crucial role for the HDACIs-induced activation of DR5 gene transcription. These provide important mechanistic insight into how HDACIs exhibit pro-apoptotic activity in clinical anti-cancer treatments when they are used in combination with other therapeutic strategies.