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Inigo JR, Chandra D. The mitochondrial unfolded protein response (UPR mt): shielding against toxicity to mitochondria in cancer. J Hematol Oncol 2022; 15:98. [PMID: 35864539 PMCID: PMC9306209 DOI: 10.1186/s13045-022-01317-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 07/11/2022] [Indexed: 12/20/2022] Open
Abstract
Mitochondria are essential for tumor growth and progression. However, the heavy demand for mitochondrial activity in cancer leads to increased production of mitochondrial reactive oxygen species (mtROS), accumulation of mutations in mitochondrial DNA, and development of mitochondrial dysfunction. If left unchecked, excessive mtROS can damage and unfold proteins in the mitochondria to an extent that becomes lethal to the tumor. Cellular systems have evolved to combat mtROS and alleviate mitochondrial stress through a quality control mechanism called the mitochondrial unfolded protein response (UPRmt). The UPRmt system is composed of chaperones and proteases, which promote protein folding or eliminate mitochondrial proteins damaged by mtROS, respectively. UPRmt is conserved and activated in cancer in response to mitochondrial stress to maintain mitochondrial integrity and support tumor growth. In this review, we discuss how mitochondria become dysfunctional in cancer and highlight the tumor-promoting functions of key components of the UPRmt.
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Affiliation(s)
- Joseph R Inigo
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Elm and Carlton Streets, Buffalo, NY, 14263, USA
| | - Dhyan Chandra
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Elm and Carlton Streets, Buffalo, NY, 14263, USA.
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Tian JJ, Levy M, Zhang X, Sinnott R, Maddela R. Counteracting Health Risks by Modulating Homeostatic Signaling. Pharmacol Res 2022; 182:106281. [PMID: 35661711 DOI: 10.1016/j.phrs.2022.106281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 05/14/2022] [Accepted: 05/27/2022] [Indexed: 10/18/2022]
Abstract
Homeostasis was initially conceptualized by Bernard and Cannon around a century ago as a steady state of physiological parameters that vary within a certain range, such as blood pH, body temperature, and heart rate1,2. The underlying mechanisms that maintain homeostasis are explained by negative feedbacks that are executed by the neuronal, endocrine, and immune systems. At the cellular level, homeostasis, such as that of redox and energy steady state, also exists and is regulated by various cell signaling pathways. The induction of homeostatic mechanism is critical for human to adapt to various disruptive insults (stressors); while on the other hand, adaptation occurs at the expense of other physiological processes and thus runs the risk of collateral damages, particularly under conditions of chronic stress. Conceivably, anti-stress protection can be achieved by stressor-mimicking medicinals that elicit adaptive responses prior to an insult and thereby serve as health risk countermeasures; and in situations where maladaptation may occur, downregulating medicinals could be used to suppress the responses and prevent subsequent pathogenesis. Both strategies are preemptive interventions particularly suited for individuals who carry certain lifestyle, environmental, or genetic risk factors. In this article, we will define and characterize a new modality of prophylactic intervention that forestalls diseases via modulating homeostatic signaling. Moreover, we will provide evidence from the literature that support this concept and distinguish it from other homeostasis-related interventions such as adaptogen, hormesis, and xenohormesis.
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Affiliation(s)
- Junqiang J Tian
- USANA Health Science, Inc., 3838 Parkway Blvd, Salt Lake City, UT 84121, USA.
| | - Mark Levy
- USANA Health Science, Inc., 3838 Parkway Blvd, Salt Lake City, UT 84121, USA
| | - Xuekai Zhang
- Beijing University of Chinese Medicine, No. 11, Bei San Huan Dong Lu, Chaoyang District, Beijing100029, China; US Center for Chinese Medicine, 14801 Physicians lane, 171 A 2nd Floor, #281, Rockville MD 20850, USA
| | - Robert Sinnott
- USANA Health Science, Inc., 3838 Parkway Blvd, Salt Lake City, UT 84121, USA
| | - Rolando Maddela
- USANA Health Science, Inc., 3838 Parkway Blvd, Salt Lake City, UT 84121, USA
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Youssef YH, Makkeyah SM, Soliman AF, Meky NH. Influence of genetic variants in asparaginase pathway on the susceptibility to asparaginase-related toxicity and patients' outcome in childhood acute lymphoblastic leukemia. Cancer Chemother Pharmacol 2021; 88:313-321. [PMID: 33959786 DOI: 10.1007/s00280-021-04290-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 04/26/2021] [Indexed: 12/21/2022]
Abstract
BACKGROUND Asparaginase (ASNase) is a key component in the treatment protocols of childhood acute lymphoblastic leukemia (ALL). Asparagine synthetase (ASNS) and the basic region leucine zipper activating transcription factor 5 (ATF5) mediate the anti-leukemic effect of ASNase. Only a few reports studied the association between polymorphisms in these genes and treatment-related toxicity and response. Therefore, the current study aimed to investigate the association of ASNS and ATF5 polymorphisms with the susceptibility to ASNase-related toxicity and disease outcome in a population of childhood ALL Egyptian patients. METHODS In this study, 88 children with ALL were enrolled and genotyped for ASNS T629A and ATF5 C362T polymorphisms using allelic discrimination assay. RESULTS The studied polymorphisms did not associate with hypersensitivity or thrombosis, while the ATF5 C362T polymorphism was associated significantly with decreased ASNase-associated pancreatitis (AAP) risk under the dominant model. Patients carrying TT/CT genotypes of ATF5 C362T polymorphism had a significantly better overall survival (OS) and longer event-free survival (EFS) compared to patients with CC genotype. Multivariate analysis confirmed the independent prognostic value of the ATF5 C362T dominant model. CONCLUSION ATF5 362TT and CT genotypes were associated with decreased risk to develop AAP and better disease outcome demonstrating a low risk for events and superior survival.
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Affiliation(s)
- Yomna H Youssef
- Zoology Department, Faculty of Science, Ain Shams University, Cairo, Egypt
| | - Sara M Makkeyah
- Pediatrics Department, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Ahmed F Soliman
- Biochemistry Department, Faculty of Science, Ain Shams University, Cairo, Egypt.
| | - Nefissa H Meky
- Zoology Department, Faculty of Science, Ain Shams University, Cairo, Egypt
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Expression patterns of activating transcription factor 5 (atf5a and atf5b) in zebrafish. Gene Expr Patterns 2020; 37:119126. [PMID: 32663618 DOI: 10.1016/j.gep.2020.119126] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 07/07/2020] [Accepted: 07/07/2020] [Indexed: 11/20/2022]
Abstract
The Activating Transcription Factor 5 (ATF5) is a basic leucine-zipper (bZIP) transcription factor (TF) with proposed stress-protective, anti-apoptotic and oncogenic roles which were all established in cell systems. In whole animals, Atf5 function seems highly context dependent. Atf5 is strongly expressed in the rodent nose and mice knockout (KO) pups have defective olfactory sensory neurons (OSNs), smaller olfactory bulbs (OB), while adults are smell deficient. It was therefore proposed that Atf5 plays an important role in maturation and maintenance of OSNs. Atf5 expression was also described in murine liver and bones where it appears to promote differentiation of progenitor cells. By contrast in the rodent brain, Atf5 was first described as uniquely expressed in neuroprogenitors and thus, proposed to drive their proliferation and inhibit their differentiation. However, it was later also found in mature neurons stressing the need for additional work in whole animals. ATF5 is well conserved with two paralogs, atf5a and atf5b in zebrafish. Here, we present the expression patterns for both from 6 h (hpf) to 5day post-fertilization (dpf). We found early expression for both genes, and from 1dpf onwards overlapping expression patterns in the inner ear and the developing liver. In the brain, at 24hpf both atf5a and atf5b were expressed in the forebrain, midbrain, and hindbrain. However, from 2dpf and onwards we only detected atf5a expression namely in the olfactory bulbs, the mesencephalon, and the metencephalon. We further evidenced additional differential expression for atf5a in the sensory neurons of the olfactory organs, and for atf5b in the neuromasts, that form the superficial sensory organ called the lateral line (LL). Our results establish the basis for future functional analyses in this lower vertebrate.
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Expression of activating transcription factor 5 (ATF5) is mediated by microRNA-520b-3p under diverse cellular stress in cancer cells. PLoS One 2020; 15:e0225044. [PMID: 32603335 PMCID: PMC7326155 DOI: 10.1371/journal.pone.0225044] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 10/28/2019] [Indexed: 12/21/2022] Open
Abstract
Cellular stress response mechanisms normally function to enhance survival and allow for cells to return to homeostasis following an adverse event. Cancer cells often co-opt these same mechanisms as a means to evade apoptosis and mitigate a state of constant cellular stress. Activating transcription factor 5 (ATF5) is upregulated under diverse stress conditions and is overexpressed in a variety of cancers. It was demonstrated ATF5 is a survival factor in transformed, but not normal cells. However, the regulation of ATF5 is not fully understood. The purpose of the present study was to investigate miRNA regulation at the 3’ untranslated region (UTR) of ATF5, with the goal of demonstrating a reversal of the upregulation of ATF5 induced under diverse cellular stress in cancer cells. A multifactorial approach using in silico analysis was employed to identify miRNAs 433-3p, 520b-3p, and 129-5p as potential regulators of ATF5, based on their predicted binding sites over the span of the ATF5 3’ UTR. Luciferase reporter assay data validated all three miRNA candidates by demonstrating direct binding to the target ATF5 3’. However, functional studies revealed miR-520b-3p as the sole candidate able to reverse the upregulation of ATF5 protein under diverse cellular stress. Additionally, miR-520b-3p levels were inversely related to ATF5 mRNA under endoplasmic reticulum stress and amino acid deprivation. This is the first evidence that regulation at the 3’ UTR is involved in modulating ATF5 levels under cellular stress and suggests an important role for miRNA-520b-3p in the regulation of ATF5.
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O'Malley J, Kumar R, Inigo J, Yadava N, Chandra D. Mitochondrial Stress Response and Cancer. Trends Cancer 2020; 6:688-701. [PMID: 32451306 DOI: 10.1016/j.trecan.2020.04.009] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 04/16/2020] [Accepted: 04/22/2020] [Indexed: 12/20/2022]
Abstract
Cancer cells survive and adapt to many types of stress including hypoxia, nutrient deprivation, metabolic, and oxidative stress. These stresses are sensed by diverse cellular signaling processes, leading to either degradation of mitochondria or alleviation of mitochondrial stress. This review discusses signaling during sensing and mitigation of stress involving mitochondrial communication with the endoplasmic reticulum, and how retrograde signaling upregulates the mitochondrial stress response to maintain mitochondrial integrity. The importance of the mitochondrial unfolded protein response, an emerging pathway that alleviates cellular stress, will be elaborated with respect to cancer. Detailed understanding of cellular pathways will establish mitochondrial stress response as a key mechanism for cancer cell survival leading to cancer progression and resistance, and provide a potential therapeutic target in cancer.
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Affiliation(s)
- Jordan O'Malley
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Rahul Kumar
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Joseph Inigo
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Nagendra Yadava
- Department of Anesthesiology and Center for Shock, Trauma, and Anesthesiology Research, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Dhyan Chandra
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA.
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Häfliger P, Graff J, Rubin M, Stooss A, Dettmer MS, Altmann KH, Gertsch J, Charles RP. The LAT1 inhibitor JPH203 reduces growth of thyroid carcinoma in a fully immunocompetent mouse model. J Exp Clin Cancer Res 2018; 37:234. [PMID: 30241549 PMCID: PMC6150977 DOI: 10.1186/s13046-018-0907-z] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 09/11/2018] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND The L-type amino acid transporter 1 (LAT1/SLC7A5) transports essential amino acids across the plasma membrane. While LAT1 is overexpressed in a variety of human neoplasms, its expression and its role in thyroid cancer is currently unknown. Anaplastic thyroid carcinoma (ATC) is a highly aggressive malignancy for which no effective therapy exists. The purpose of this study was to explore whether the inhibition of LAT1 in ATC would affect tumor growth both in vitro and in vivo. METHODS LAT1 was pharmacologically blocked by JPH203 in human ATC and papillary thyroid cancer (PTC) cell lines. The effects on proliferation and mTORC1 activity were addressed in vitro. A genetically engineered mouse model of ATC was used to address the effect of blocking LAT1 on tumor growth in vivo. SLC7A5 transcription was measured in patient-derived ATC samples to address the clinical relevance of the findings. RESULTS LAT1 block by JPH203 reduced proliferation and mTORC1 signaling in human thyroid cancer cell lines. SLC7A5 transcription was upregulated in ATC tissues derived from a genetically engineered mouse model and in ATC samples recovered from patients. JPH203 treatment induced thyroid tumor growth arrest in vivo in a fully immunocompetent mouse model of thyroid cancer. Additionally, analysis of publicly available datasets of thyroid carcinomas revealed that high LAT1 expression is associated with potentially untreatable PTC presenting reduced NIS/SLC5A5 transcription and with ATC. CONCLUSIONS These preclinical results show that LAT1 inhibition is a novel therapeutic approach in the context of thyroid cancers, and more interestingly in untreatable thyroid cancers.
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Affiliation(s)
- Pascal Häfliger
- Institute of Biochemistry and Molecular Medicine, and Swiss National Center of Competence in Research (NCCR) TransCure, University of Bern, Bühlstrasse 28, CH-3012 Bern, Switzerland
- Present address: Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, USA
| | - Julien Graff
- Institute of Pharmaceutical Sciences, and Swiss National Center of Competence in Research (NCCR) TransCure, ETH Zürich, Vladimir-Prelog-Weg 4, CH-8093 Zürich, Switzerland
| | - Matthias Rubin
- Institute of Biochemistry and Molecular Medicine, and Swiss National Center of Competence in Research (NCCR) TransCure, University of Bern, Bühlstrasse 28, CH-3012 Bern, Switzerland
| | - Amandine Stooss
- Institute of Biochemistry and Molecular Medicine, and Swiss National Center of Competence in Research (NCCR) TransCure, University of Bern, Bühlstrasse 28, CH-3012 Bern, Switzerland
| | - Matthias S. Dettmer
- Institute of Pathology, University of Bern, Murtenstrasse 31, CH-3008 Bern, Switzerland
| | - Karl-Heinz Altmann
- Institute of Pharmaceutical Sciences, and Swiss National Center of Competence in Research (NCCR) TransCure, ETH Zürich, Vladimir-Prelog-Weg 4, CH-8093 Zürich, Switzerland
| | - Jürg Gertsch
- Institute of Biochemistry and Molecular Medicine, and Swiss National Center of Competence in Research (NCCR) TransCure, University of Bern, Bühlstrasse 28, CH-3012 Bern, Switzerland
| | - Roch-Philippe Charles
- Institute of Biochemistry and Molecular Medicine, and Swiss National Center of Competence in Research (NCCR) TransCure, University of Bern, Bühlstrasse 28, CH-3012 Bern, Switzerland
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Comparative Analysis of Immune Cells Reveals a Conserved Regulatory Lexicon. Cell Syst 2018; 6:381-394.e7. [PMID: 29454939 DOI: 10.1016/j.cels.2018.01.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 10/06/2017] [Accepted: 12/30/2017] [Indexed: 12/13/2022]
Abstract
Most well-characterized enhancers are deeply conserved. In contrast, genome-wide comparative studies of steady-state systems showed that only a small fraction of active enhancers are conserved. To better understand conservation of enhancer activity, we used a comparative genomics approach that integrates temporal expression and epigenetic profiles in an innate immune system. We found that gene expression programs diverge among mildly induced genes, while being highly conserved for strongly induced genes. The fraction of conserved enhancers varies greatly across gene expression programs, with induced genes and early-response genes, in particular, being regulated by a higher fraction of conserved enhancers. Clustering of conserved accessible DNA sequences within enhancers resulted in over 60 sequence motifs including motifs for known factors, as well as many with unknown function. We further show that the number of instances of these motifs is a strong predictor of the responsiveness of a gene to pathogen detection.
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Hernández IH, Torres-Peraza J, Santos-Galindo M, Ramos-Morón E, Fernández-Fernández MR, Pérez-Álvarez MJ, Miranda-Vizuete A, Lucas JJ. The neuroprotective transcription factor ATF5 is decreased and sequestered into polyglutamine inclusions in Huntington's disease. Acta Neuropathol 2017; 134:839-850. [PMID: 28861715 DOI: 10.1007/s00401-017-1770-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 08/03/2017] [Accepted: 08/21/2017] [Indexed: 02/07/2023]
Abstract
Activating transcription factor-5 (ATF5) is a stress-response transcription factor induced upon different cell stressors like fasting, amino-acid limitation, cadmium or arsenite. ATF5 is also induced, and promotes transcription of anti-apoptotic target genes like MCL1, during the unfolded protein response (UPR) triggered by endoplasmic reticulum stress. In the brain, high ATF5 levels are found in gliomas and also in neural progenitor cells, which need to decrease their ATF5 levels for differentiation into mature neurons or glia. This initially led to believe that ATF5 is not expressed in adult neurons. More recently, we reported basal neuronal ATF5 expression in adult mouse brain and its neuroprotective induction during UPR in a mouse model of status epilepticus. Here we aimed to explore whether ATF5 is also expressed by neurons in human brain both in basal conditions and in Huntington's disease (HD), where UPR has been described to be partially impaired due to defective ATF6 processing. Apart from confirming that ATF5 is present in human adult neurons, here we report accumulation of ATF5 within the characteristic polyglutamine-containing neuronal nuclear inclusions in brains of HD patients and mice. This correlates with decreased levels of soluble ATF5 and of its antiapoptotic target MCL1. We then confirmed the deleterious effect of ATF5 deficiency in a Caenorhabditis elegans model of polyglutamine-induced toxicity. Finally, ATF5 overexpression attenuated polyglutamine-induced apoptosis in a cell model of HD. These results reflect that decreased ATF5 in HD-probably secondary to sequestration into inclusions-renders neurons more vulnerable to mutant huntingtin-induced apoptosis and that ATF5-increasing interventions might have therapeutic potential for HD.
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Affiliation(s)
- Ivó H Hernández
- Centro de Biología Molecular Severo Ochoa (CBMSO) CSIC/UAM, Madrid, Spain
- Networking Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - Jesús Torres-Peraza
- Centro de Biología Molecular Severo Ochoa (CBMSO) CSIC/UAM, Madrid, Spain
- Networking Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
- Gerència d'Atenció Primària del Servei de Salut de les Illes Balears (IB-SALUT), Palma, Spain
| | - María Santos-Galindo
- Centro de Biología Molecular Severo Ochoa (CBMSO) CSIC/UAM, Madrid, Spain
- Networking Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Eloísa Ramos-Morón
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
| | - M Rosario Fernández-Fernández
- Centro de Biología Molecular Severo Ochoa (CBMSO) CSIC/UAM, Madrid, Spain
- Networking Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - María J Pérez-Álvarez
- Centro de Biología Molecular Severo Ochoa (CBMSO) CSIC/UAM, Madrid, Spain
- Networking Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - Antonio Miranda-Vizuete
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
| | - José J Lucas
- Centro de Biología Molecular Severo Ochoa (CBMSO) CSIC/UAM, Madrid, Spain.
- Networking Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain.
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Yokouchi Y, Imaoka M, Niino N, Kiyosawa N, Kai K. Comprehensive Evaluation of (+)-Usnic Acid–induced Cardiotoxicity in Rats by Sequential Cross-omics Analysis. Toxicol Pathol 2017; 45:481-492. [DOI: 10.1177/0192623317707074] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Two-week administration of (+)-usnic acid (UA) induces mitochondrial swelling of cardiomyocytes, and toxicogenomic analysis of the heart revealed upregulation of oxidative stress, amino acid limitation, and endoplasmic reticulum stress–related genes in rats. To analyze the pathogenesis, UA was orally administrated to rats for 1, 4, 7, and 14 days, and sequential histopathological, genomic, and metabolomic analyses were performed on the heart, liver, and plasma. As a result, mitochondrial swelling of cardiomyocytes was observed on day 15 preceded by genomic upregulation on days 5 and 8. Of the focused gene groups, amino acid limitation–related genes represented by Mthfd2 showed numerically higher values or upregulation from day 5, which was sustained through the experimental period. On the contrary, oxidative stress–related genes were upregulated temporally on day 5. In metabolomic analysis, amino acids such as taurocholate and their metabolites fluctuated in concert with the upregulation of amino acid limitation–related genes in the heart, liver, and plasma. Moreover, accumulations of bile acids were manifested in all the tested tissues, while no histopathological change was seen in the liver. Increased bile acids might have an indirect effect on the myocardium; however, more detailed analysis is required. In conclusion, amino acid limitation was suggested as the pivotal toxic trigger of UA-induced cardiotoxicity.
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Affiliation(s)
- Y. Yokouchi
- Translational Medicine and Clinical Pharmacology Department, R&D Division, Daiichi Sankyo Co., Ltd., Tokyo, Japan
| | - M. Imaoka
- Medicinal Safety Research Laboratories, R&D Division, Daiichi Sankyo Co., Ltd., Tokyo, Japan
| | - N. Niino
- Medicinal Safety Research Laboratories, R&D Division, Daiichi Sankyo Co., Ltd., Tokyo, Japan
| | - N. Kiyosawa
- Translational Medicine and Clinical Pharmacology Department, R&D Division, Daiichi Sankyo Co., Ltd., Tokyo, Japan
| | - K. Kai
- Medicinal Safety Research Laboratories, R&D Division, Daiichi Sankyo Co., Ltd., Tokyo, Japan
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Fiorese CJ, Haynes CM. Integrating the UPR mt into the mitochondrial maintenance network. Crit Rev Biochem Mol Biol 2017; 52:304-313. [PMID: 28276702 DOI: 10.1080/10409238.2017.1291577] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Mitochondrial function is central to many different processes in the cell, from oxidative phosphorylation to the synthesis of iron-sulfur clusters. Therefore, mitochondrial dysfunction underlies a diverse array of diseases, from neurodegenerative diseases to cancer. Stress can be communicated to the cytosol and nucleus from the mitochondria through many different signals, and in response the cell can effect everything from transcriptional to post-transcriptional responses to protect the mitochondrial network. How these responses are coordinated have only recently begun to be understood. In this review, we explore how the cell maintains mitochondrial function, focusing on the mitochondrial unfolded protein response (UPRmt), a transcriptional response that can activate a wide array of programs to repair and restore mitochondrial function.
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Affiliation(s)
- Christopher J Fiorese
- a Department of Molecular Cell and Cancer Biology , University of Massachusetts Medical School , Worcester , MA , USA.,b BCMB Allied Program , Weill Cornell Medical College , New York , NY , USA
| | - Cole M Haynes
- a Department of Molecular Cell and Cancer Biology , University of Massachusetts Medical School , Worcester , MA , USA.,b BCMB Allied Program , Weill Cornell Medical College , New York , NY , USA
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12
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Vicari L, La Rosa C, Forte S, Calabrese G, Colarossi C, Aiello E, Salluzzo S, Memeo L. Differential expression of two activating transcription factor 5 isoforms in papillary thyroid carcinoma. Onco Targets Ther 2016; 9:6225-6231. [PMID: 27785070 PMCID: PMC5067000 DOI: 10.2147/ott.s113194] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Activating transcription factor 5 (ATF5) is a member of the activating transcription/cAMP response element-binding protein family of basic leucine zipper proteins that plays an important role in cell survival, differentiation, proliferation, and apoptosis. The ATF5 gene generates two transcripts: ATF5 isoform 1 and ATF5 isoform 2. A number of studies indicate that ATF5 could be an attractive target for therapeutic intervention in several tumor types; however, so far, the role of ATF5 has not been investigated in papillary thyroid carcinoma (PTC). METHODS Quantitative real-time reverse transcription polymerase chain reaction and immuno-histochemical staining were used to study ATF5 mRNA and protein expression in PTC. RESULTS We report here that ATF5 is expressed more in PTC tissue than in normal thyroid tissue. Furthermore, this is the first study that describes the presence of both ATF5 isoforms in PTC. CONCLUSION These findings could provide potential applications in PTC cancer treatment.
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Affiliation(s)
| | - Cristina La Rosa
- Department of Experimental Oncology, Istituto Oncologico del Mediterraneo, Viagrande CT, Italy
- Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Roma, Italy
| | | | | | - Cristina Colarossi
- Department of Experimental Oncology, Istituto Oncologico del Mediterraneo, Viagrande CT, Italy
| | - Eleonora Aiello
- Department of Experimental Oncology, Istituto Oncologico del Mediterraneo, Viagrande CT, Italy
| | - Salvatore Salluzzo
- Department of Experimental Oncology, Istituto Oncologico del Mediterraneo, Viagrande CT, Italy
| | - Lorenzo Memeo
- IOM Ricerca srl, Viagrande CT, Italy
- Department of Experimental Oncology, Istituto Oncologico del Mediterraneo, Viagrande CT, Italy
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13
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Rondón-Lagos M, Rangel N, Di Cantogno LV, Annaratone L, Castellano I, Russo R, Manetta T, Marchiò C, Sapino A. Effect of low doses of estradiol and tamoxifen on breast cancer cell karyotypes. Endocr Relat Cancer 2016; 23:635-50. [PMID: 27357940 PMCID: PMC5064758 DOI: 10.1530/erc-16-0078] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 06/29/2016] [Indexed: 12/21/2022]
Abstract
Evidence supports a role of 17&-estradiol (E2) in carcinogenesis and the large majority of breast carcinomas are dependent on estrogen. The anti-estrogen tamoxifen (TAM) is widely used for both treatment and prevention of breast cancer; however, it is also carcinogenic in human uterus and rat liver, highlighting the profound complexity of its actions. The nature of E2- or TAM-induced chromosomal damage has been explored using relatively high concentrations of these agents, and only some numerical aberrations and chromosomal breaks have been analyzed. This study aimed to determine the effects of low doses of E2 and TAM (10(&8 )mol L(&1) and 10(&6 )mol L(&1) respectively) on karyotypes of MCF7, T47D, BT474, and SKBR3 breast cancer cells by comparing the results of conventional karyotyping and multi-FISH painting with cell proliferation. Estrogen receptor (ER)-positive (+) cells showed an increase in cell proliferation after E2 treatment (MCF7, T47D, and BT474) and a decrease after TAM treatment (MCF7 and T47D), whereas in ER& cells (SKBR3), no alterations in cell proliferation were observed, except for a small increase at 96 h. Karyotypes of both ER+ and ER& breast cancer cells increased in complexity after treatments with E2 and TAM leading to specific chromosomal abnormalities, some of which were consistent throughout the treatment duration. This genotoxic effect was higher in HER2+ cells. The ER&/HER2+ SKBR3 cells were found to be sensitive to TAM, exhibiting an increase in chromosomal aberrations. These in vitro results provide insights into the potential role of low doses of E2 and TAM in inducing chromosomal rearrangements in breast cancer cells.
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Affiliation(s)
| | - Nelson Rangel
- Department of Medical SciencesUniversity of Turin, Turin, Italy Natural and Mathematical Sciences FacultyUniversidad del Rosario, Bogotá, Colombia
| | | | | | | | - Rosalia Russo
- Department of Medical SciencesUniversity of Turin, Turin, Italy
| | - Tilde Manetta
- Department of Public Health and PediatricsUniversity of Turin, Turin, Italy
| | | | - Anna Sapino
- Department of Medical SciencesUniversity of Turin, Turin, Italy Candiolo Cancer InstituteFPO-IRCCS, Candiolo, Italy
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Bellato HM, Hajj GNM. Translational control by eIF2α in neurons: Beyond the stress response. Cytoskeleton (Hoboken) 2016; 73:551-565. [PMID: 26994324 DOI: 10.1002/cm.21294] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 03/14/2016] [Accepted: 03/14/2016] [Indexed: 12/21/2022]
Abstract
The translation of mRNAs is a tightly controlled process that responds to multiple signaling pathways. In neurons, this control is also exerted locally due to the differential necessity of proteins in axons and dendrites. The phosphorylation of the alpha subunit of the translation initiation factor 2 (eIF2α) is one of the mechanisms of translational control. The phosphorylation of eIF2α has classically been viewed as a stress response, halting translation initiation. However, in the nervous system this type of regulation has been related to other mechanisms besides stress response, such as behavior, memory consolidation and nervous system development. Additionally, neurodegenerative diseases have a major stress component, thus eIF2α phosphorylation plays a preeminent role and its modulation is currently viewed as a new opportunity for therapeutic interventions. This review consolidates current information regarding eIF2α phosphorylation in neurons and its impact in neurodegenerative diseases. © 2016 Wiley Periodicals, Inc.
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Umemura M, Tsunematsu K, Shimizu YI, Nakano H, Takahashi S, Higashiura Y, Okabe M, Takahashi Y. Activating transcription factor 5 is required for mouse olfactory bulb development via interneuron. Biosci Biotechnol Biochem 2015; 79:1082-9. [PMID: 25704077 DOI: 10.1080/09168451.2015.1012042] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Activating transcription factor 5 (ATF5) is a stress response transcription factor of the cAMP-responsive element-binding/ATF family. Earlier, we reported that ATF5 expression is up-regulated in response to stress, such as amino acid limitation or arsenite exposure. Although ATF5 is widely expressed in the brain and the olfactory epithelium, the role of ATF5 is not fully understood. Here, the olfactory bulbs (OBs) of ATF5-deficient mice are smaller than those of wild-type mice. Histological analysis reveals the disturbed laminar structure of the OB, showing the thinner olfactory nerve layer, and a reduced number of interneurons. This is mainly due to the reduced number of bromodeoxyuridine-positive proliferating cells in the subventricular zone, where the interneuron progenitors are formed and migrate to the OBs. Moreover, the olfaction-related aggressive behavior of ATF5-deficient mice is reduced compared to wild-type mice. Our data suggest that ATF5 plays a crucial role in mouse OB development via interneuron.
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Affiliation(s)
- Mariko Umemura
- a School of Life Sciences , Tokyo University of Pharmacy and Life Sciences , Hachioji , Japan
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16
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Stabilization of ATF5 by TAK1-Nemo-like kinase critically regulates the interleukin-1β-stimulated C/EBP signaling pathway. Mol Cell Biol 2014; 35:778-88. [PMID: 25512613 DOI: 10.1128/mcb.01228-14] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Interleukin-1β (IL-1β) is a key proinflammatory cytokine that initiates several signaling cascades, including those involving CCAAT/enhancer binding proteins (C/EBPs). The mechanism by which IL-1β propagates a signal that activates C/EBP has remained elusive. Nemo-like kinase (NLK) is a mitogen-activated protein kinase (MAPK)-like kinase associated with many pathways and phenotypes that are not yet well understood. Using a luciferase reporter screen, we found that IL-1β-induced C/EBP activation was positively regulated by NLK. Overexpression of NLK activated C/EBP and potentiated IL-1β-triggered C/EBP activation, whereas knockdown or knockout of NLK had the opposite effect. NLK interacted with activating transcription factor 5 (ATF5) and inhibited the proteasome-dependent degradation of ATF5 in a kinase-independent manner. Consistently, NLK deficiency resulted in decreased levels of ATF5. NLK cooperated with ATF5 to activate C/EBP, whereas NLK could not activate C/EBP upon knockdown of ATF5. Moreover, TAK1, a downstream effector of IL-1β that acts upstream of NLK, mimicked the ability of NLK to stabilize ATF5 and activate C/EBP. Thus, our findings reveal the TAK1-NLK pathway as a novel regulator of basal or IL-1β-triggered C/EBP activation though stabilization of ATF5.
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17
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Abe T, Kojima M, Akanuma S, Iwashita H, Yamazaki T, Okuyama R, Ichikawa K, Umemura M, Nakano H, Takahashi S, Takahashi Y. N-terminal hydrophobic amino acids of activating transcription factor 5 (ATF5) protein confer interleukin 1β (IL-1β)-induced stabilization. J Biol Chem 2013; 289:3888-900. [PMID: 24379400 DOI: 10.1074/jbc.m113.491217] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Activating transcription factor 5 (ATF5) is a stress-response transcription factor that responds to amino acid limitation and exposure to cadmium chloride (CdCl2) and sodium arsenite (NaAsO2). The N-terminal amino acids contribute to the destabilization of the ATF5 protein in steady-state conditions and serve as a stabilization domain in the stress response after CdCl2 or NaAsO2 exposure. In this study, we show that interleukin 1β (IL-1β), a proinflammatory cytokine, increases the expression of ATF5 protein in HepG2 hepatoma cells in part by stabilizing the ATF5 protein. The N-terminal domain rich in hydrophobic amino acids that is predicted to form a hydrophobic network was responsible for destabilization in steady-state conditions and served as an IL-1β response domain. Furthermore, IL-1β increased the translational efficiency of ATF5 mRNA via the 5' UTRα and phosphorylation of the eukaryotic translation initiation factor 2α (eIF2α). ATF5 knockdown in HepG2 cells up-regulated the IL-1β-induced expression of the serum amyloid A 1 (SAA1) and SAA2 genes. Our results show that the N-terminal hydrophobic amino acids play an important role in the regulation of ATF5 protein expression in IL-1β-mediated immune response and that ATF5 is a negative regulator for IL-1β-induced expression of SAA1 and SAA2 in HepG2 cells.
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Affiliation(s)
- Takanori Abe
- From the Laboratory of Environmental Molecular Physiology
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18
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Yokouchi Y, Imaoka M, Niino N, Kiyosawa N, Sayama A, Jindo T. (+)-Usnic Acid-induced Myocardial Toxicity in Rats. Toxicol Pathol 2013; 43:424-34. [DOI: 10.1177/0192623313504308] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
(+)-Usnic acid (UA) has been known to be a strong uncoupler, and mitochondrial and endoplasmic reticulum (ER)–related stresses are suggested to be involved in the mechanism of hepatotoxicity. However, it has not been clarified whether UA causes toxicity in other mitochondria-rich organs such as the heart. We elucidated whether UA induces cardiotoxicity and its mechanism. UA was orally administered to rats for 14 days, and laboratory and histopathological examinations were performed in conjunction with toxicogenomic analysis. As a result, there was no alteration in blood chemistry, whereas cytoplasmic rarefaction of myocardium was observed microscopically. This finding corresponded to the swollen mitochondria observed ultrastructurally. Immunohistochemically, expression of prohibitin, indicating mitochondrial imbalance, increased in the sarcoplasmic area. Toxicogenomic analysis highlighted the upregulation of gene groups consisting of oxidative stress, ER stress, and amino acid limitation. Interestingly, the number of upregulated genes was larger in the amino acid limitation-related gene group than that in other groups, implying that amino acid limitation might be one of the sources of oxidative stress, not only mitochondria and ER-originated stresses. In conclusion, the heart was manifested to be one of the target organs of UA. Mitochondrial imbalance with complex stresses may be involved in the toxic mechanism.
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Affiliation(s)
- Yusuke Yokouchi
- Medicinal Safety Research Laboratories, Daiichi-Sankyo Co., Ltd., Tokyo, Japan
| | - Masako Imaoka
- Medicinal Safety Research Laboratories, Daiichi-Sankyo Co., Ltd., Tokyo, Japan
| | - Noriyo Niino
- Medicinal Safety Research Laboratories, Daiichi-Sankyo Co., Ltd., Tokyo, Japan
| | - Naoki Kiyosawa
- Medicinal Safety Research Laboratories, Daiichi-Sankyo Co., Ltd., Tokyo, Japan
| | - Ayako Sayama
- Medicinal Safety Research Laboratories, Daiichi-Sankyo Co., Ltd., Tokyo, Japan
| | - Toshimasa Jindo
- Medicinal Safety Research Laboratories, Daiichi-Sankyo Co., Ltd., Tokyo, Japan
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19
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Hatano M, Umemura M, Kimura N, Yamazaki T, Takeda H, Nakano H, Takahashi S, Takahashi Y. The 5'-untranslated region regulates ATF5 mRNA stability via nonsense-mediated mRNA decay in response to environmental stress. FEBS J 2013; 280:4693-707. [PMID: 23876217 DOI: 10.1111/febs.12440] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 07/08/2013] [Accepted: 07/15/2013] [Indexed: 11/28/2022]
Abstract
We previously reported that activating transcription factor 5 (ATF5) mRNA increases in response to amino acid limitation, and that this increase is dependent on mRNA stabilization. The ATF5 gene allows transcription of mRNAs with two alternative 5'-UTRs, 5'-UTRα and 5'-UTRβ, derived from exon 1α and exon 1β. 5'-UTRα contains the upstream open reading frames uORF1 and uORF2. Phosphorylation of eukaryotic initiation factor 2α during the integrated stress response had been previously shown to lead to bypassing of uORF2 translation and production of ATF5 protein. Translation of uORF2 is expected to result in translational termination at a position 125 nucleotides upstream of the exon junction, and this fits the criterion of a nonsense-mediated decay target mRNA. We investigated the potential role of 5'-UTRα in the control of mRNA stabilization, and found that 5'-UTRα reduced the stability of ATF5 mRNA. 5'-UTRα-regulated destabilization of mRNA was suppressed by knockdown of the nonsense-mediated decay factors Upf1 and Upf2. Mutation of the downstream AUG (uAUG2) rendered mRNA refractory to Upf1 and Upf2 knockdown. Moreover, 5'-UTRα-regulated down-regulation was hindered by amino acid limitation and tunicamycin treatment, and stress-induced phosphorylation of eukaryotic initiation factor 2α was involved in stabilization of ATF5 mRNA. These studies show that ATF5 mRNA is a naturally occurring normal mRNA target of nonsense-mediated decay, and provide evidence for linkage between stress-regulated translational regulation and the mRNA decay pathway. This linkage constitutes a mechanism that regulates expression of stress response genes.
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Affiliation(s)
- Masaya Hatano
- Laboratory of Environmental Molecular Physiology, School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Japan
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20
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ATF5 polymorphisms influence ATF function and response to treatment in children with childhood acute lymphoblastic leukemia. Blood 2011; 118:5883-90. [PMID: 21972289 DOI: 10.1182/blood-2011-05-355560] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Asparaginase is a standard and critical component in the therapy of childhood acute lymphoblastic leukemia. Asparagine synthetase (ASNS) and the basic region leucine zipper activating transcription factor 5 (ATF5) and arginosuccinate synthase 1 (ASS1) have been shown to mediate the antileukemic effect of asparaginase and to display variable expression between leukemia cells that are resistant and sensitive to treatment. Fourteen polymorphisms in the regulatory and coding regions of these genes were investigated for an association with acute lymphoblastic leukemia outcome. Lower event-free survival (EFS) was associated with ATF5 T1562C, tandem-repeat ASNS polymorphism, derived haplotype, and ASS1 G1343T and G34T substitutions (P ≤ .03). Associations were limited to patients who received Escherichia coli asparaginase. Variations that sustained correction for multiple testing (ATF5 T1562C, P = .005; ASNS tandem-repeat and related haplotype, P ≤ .01) were subsequently analyzed in the replication cohort. The E coli-dependent association of the ATF5 T1562 allele with reduced EFS was confirmed (P = .01). A gene-reporter assay showed that the haplotype tagged by T1562 had higher promoter activity (P ≤ .01). The remaining regulatory polymorphisms also appeared to affect ATF5 function; 2 additional high-activity haplotypes were identified (P ≤ .02) and were further corroborated by quantitative mRNA analysis in lymphoblastoid cell lines. The ATF5-regulated increase in ASNS expression in response to more efficacious E coli-induced asparagine depletion may explain our observed results.
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21
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Li G, Xu Y, Guan D, Liu Z, Liu DX. HSP70 protein promotes survival of C6 and U87 glioma cells by inhibition of ATF5 degradation. J Biol Chem 2011; 286:20251-9. [PMID: 21521685 DOI: 10.1074/jbc.m110.211771] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Although both the heat shock protein 70 (HSP70) and the activating transcription factor 5 (ATF5) have been shown to promote cell survival of transformed cells but not survival of non-transformed cells, the relationship of the two molecules is unknown. Here we show that HSP70 and ATF5 are concomitantly up-regulated upon transient but down-regulated over prolonged cellular stress and apoptotic stimulation in the rat C6 glioma and human U87 glioma cells. HSP70 interacts strongly with the N-terminal activation domain of ATF5, which is expected to be rigid and uniquely structured under physiological conditions because of extraordinary high concentration (over 25%) of proline residues. Binding of HSP70 to ATF5 is an ATP-driven process and requires functional ATPase on the nucleotide binding domain of the HSP70 molecule. Overexpression of HSP70 dramatically stabilizes the ATF5 protein, which is otherwise subject to rapid degradation, facilitated by both proteasome-dependent and caspase-dependent processes, whereas HSP70 depletion leads to acceleration of ATF5 degradation and transcription repression of Bcl-2 and Egr-1, which are downstream targets of ATF5 in C6 and U87 glioma cells. Our data reveal an essential role for HSP70 in maintaining high levels of ATF5 expression in glioma cells and support the conclusion that ATF5 is an important substrate protein of HSP70 that mediates HSP70-promoted cell survival in glioma cells.
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Affiliation(s)
- Guangfu Li
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine, Hershey, Pennsylvania 17033, USA
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22
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Yamazaki T, Ohmi A, Kurumaya H, Kato K, Abe T, Yamamoto H, Nakanishi N, Okuyama R, Umemura M, Kaise T, Watanabe R, Okawa Y, Takahashi S, Takahashi Y. Regulation of the human CHOP gene promoter by the stress response transcription factor ATF5 via the AARE1 site in human hepatoma HepG2 cells. Life Sci 2010; 87:294-301. [PMID: 20654631 DOI: 10.1016/j.lfs.2010.07.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2009] [Revised: 06/27/2010] [Accepted: 07/01/2010] [Indexed: 01/28/2023]
Abstract
AIMS Activating transcription factor (ATF) 5 is a member of the cAMP response element-binding protein (CREB)/ATF family of transcription factors. We have shown that ATF5 is a stress response transcription factor that responds to amino acid limitation, arsenite exposure, or cadmium exposure. In this study we investigated whether ATF5 is involved in the regulation of CCAAT/enhancer-binding protein (C/EBP) homologous protein (CHOP) gene expression. MAIN METHODS We used a transient transfection system to express ATF5 and analyzed the regulation of CHOP gene promoter in human hepatoma, HepG2 cells. We also studied the effect of ATF5 knockdown on arsenite-induced CHOP protein expression and arsenite-induced cell death of HepG2 cells. KEY FINDINGS We showed that ATF5 activates the CHOP gene promoter in HepG2 cells. Both deletion analysis and point mutations of the promoter revealed that amino acid response element (AARE) 1 is responsible for ATF5-dependent promoter activation. Furthermore, the existence of either AARE1 or activating protein-1 (AP-1) site is sufficient for transcriptional activation of the CHOP gene promoter by arsenite exposure, although complete induction requires the existence of both elements. We also demonstrated that knockdown of ATF5 reduced arsenite-induced CHOP protein expression and arsenite-induced cell death of HepG2 cells. SIGNIFICANCE These results suggested that the CHOP gene is a potential target for ATF5, and that ATF5 raises the arsenite-induced CHOP gene expression level via the AARE1 site in HepG2 cells.
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Affiliation(s)
- Takashi Yamazaki
- The Laboratory of Environmental Molecular Physiology, School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
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23
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Wei Y, Ge Y, Zhou F, Chen H, Cui C, Liu D, Yang Z, Wu G, Gu J, Jiang J. Identification and characterization of the promoter of human ATF5 gene. J Biochem 2010; 148:171-8. [DOI: 10.1093/jb/mvq047] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Abstract
Several decades of research have sought to characterize tumor cell metabolism in the hope that tumor-specific activities can be exploited to treat cancer. Having originated from Warburg's seminal observation of aerobic glycolysis in tumor cells, most of this attention has focused on glucose metabolism. However, since the 1950s cancer biologists have also recognized the importance of glutamine (Q) as a tumor nutrient. Glutamine contributes to essentially every core metabolic task of proliferating tumor cells: it participates in bioenergetics, supports cell defenses against oxidative stress and complements glucose metabolism in the production of macromolecules. The interest in glutamine metabolism has been heightened further by the recent findings that c-myc controls glutamine uptake and degradation, and that glutamine itself exerts influence over a number of signaling pathways that contribute to tumor growth. These observations are stimulating a renewed effort to understand the regulation of glutamine metabolism in tumors and to develop strategies to target glutamine metabolism in cancer. In this study we review the protean roles of glutamine in cancer, both in the direct support of tumor growth and in mediating some of the complex effects on whole-body metabolism that are characteristic of tumor progression.
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25
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Li G, Li W, Angelastro JM, Greene LA, Liu DX. Identification of a novel DNA binding site and a transcriptional target for activating transcription factor 5 in c6 glioma and mcf-7 breast cancer cells. Mol Cancer Res 2009; 7:933-43. [PMID: 19531563 DOI: 10.1158/1541-7786.mcr-08-0365] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Recent reports indicate that the activating transcription factor 5 (ATF5) is required for the survival of cancer cells but not for noncancer cells. However, the mechanisms by which ATF5 regulates genes and promotes cell survival are not clear. Using a cyclic amplification and selection of targets (CASTing) approach, we identified a novel ATF5 consensus DNA binding sequence. We show in C6 glioma and MCF-7 breast cancer cells that ATF5 occupies this sequence and that ATF5 activates reporter gene expression driven by this site. Conversely, reporter activity is diminished when ATF5 activity is blocked or when ATF5 expression is down-regulated by serum withdrawal. We further show that early growth response factor 1 (Egr-1), whose promoter contains two adjacent ATF5 consensus binding sites at a conserved promoter position in rat, mouse, and human, is targeted and regulated by ATF5 in C6 and MCF-7 cells. These data provide new insight on the mechanisms by which ATF5 promotes gene regulation and cancer-specific cell survival.
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Affiliation(s)
- Guangfu Li
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine, Hershey, 17033, USA
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26
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Shimizu YI, Morita M, Ohmi A, Aoyagi S, Ebihara H, Tonaki D, Horino Y, Iijima M, Hirose H, Takahashi S, Takahashi Y. Fasting induced up-regulation of activating transcription factor 5 in mouse liver. Life Sci 2009; 84:894-902. [DOI: 10.1016/j.lfs.2009.04.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2008] [Revised: 03/27/2009] [Accepted: 03/31/2009] [Indexed: 10/20/2022]
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Brasse-Lagnel C, Lavoinne A, Husson A. Control of mammalian gene expression by amino acids, especially glutamine. FEBS J 2009; 276:1826-44. [PMID: 19250320 DOI: 10.1111/j.1742-4658.2009.06920.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Molecular data rapidly accumulating on the regulation of gene expression by amino acids in mammalian cells highlight the large variety of mechanisms that are involved. Transcription factors, such as the basic-leucine zipper factors, activating transcription factors and CCAAT/enhancer-binding protein, as well as specific regulatory sequences, such as amino acid response element and nutrient-sensing response element, have been shown to mediate the inhibitory effect of some amino acids. Moreover, amino acids exert a wide range of effects via the activation of different signalling pathways and various transcription factors, and a number of cis elements distinct from amino acid response element/nutrient-sensing response element sequences were shown to respond to changes in amino acid concentration. Particular attention has been paid to the effects of glutamine, the most abundant amino acid, which at appropriate concentrations enhances a great number of cell functions via the activation of various transcription factors. The glutamine-responsive genes and the transcription factors involved correspond tightly to the specific effects of the amino acid in the inflammatory response, cell proliferation, differentiation and survival, and metabolic functions. Indeed, in addition to the major role played by nuclear factor-kappaB in the anti-inflammatory action of glutamine, the stimulatory role of activating protein-1 and the inhibitory role of C/EBP homology binding protein in growth-promotion, and the role of c-myc in cell survival, many other transcription factors are also involved in the action of glutamine to regulate apoptosis and intermediary metabolism in different cell types and tissues. The signalling pathways leading to the activation of transcription factors suggest that several kinases are involved, particularly mitogen-activated protein kinases. In most cases, however, the precise pathways from the entrance of the amino acid into the cell to the activation of gene transcription remain elusive.
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Affiliation(s)
- Carole Brasse-Lagnel
- Appareil Digestif, Environnement et Nutrition, EA 4311, Université de Rouen, France
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Cadmium interferes with the degradation of ATF5 via a post-ubiquitination step of the proteasome degradation pathway. Biochem Biophys Res Commun 2009; 380:673-8. [PMID: 19285020 DOI: 10.1016/j.bbrc.2009.01.158] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2009] [Accepted: 01/26/2009] [Indexed: 11/21/2022]
Abstract
ATF5 is a member of the CREB/ATF family of transcription factors. In the current study, using a transient transfection system to express FLAG epitope fusion proteins of ATF5, we have shown that CdCl(2) or NaAsO(3) increases the protein levels of ATF5 in cells, and that cadmium stabilizes the ATF5 protein. Proteasome inhibitors had a similar effect to cadmium on the cellular accumulation of ATF5. Proteasome inhibition led to an increase in ubiquitinated ATF5, while cadmium did not appear to reduce the extent of ATF5 ubiquitination. ATF5 contains a putative nuclear export signal within its N-terminus. We demonstrated that whereas deletion of N-terminal region resulted in a increase of ATF5 levels, this region does not appear to be involved in the ubiquitination of ATF5. These results indicate that ATF5 is targeted for degradation by the ubiquitin-proteasome pathway, and that cadmium slows the rate of ATF5 degradation via a post-ubiquitination mechanism.
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29
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Greene LA, Lee HY, Angelastro JM. The transcription factor ATF5: role in neurodevelopment and neural tumors. J Neurochem 2008; 108:11-22. [PMID: 19046351 DOI: 10.1111/j.1471-4159.2008.05749.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
We review recent findings regarding the properties of ATF5 and the major roles that this transcription factor plays in development of the nervous system and in survival of neural tumors. ATF5 is a widely expressed basic leucine zipper protein that has been subject to limited characterization. It is highly expressed in zones of neuroprogenitor cell proliferation. In vitro and in vivo studies indicate that it functions there to promote neuroprogenitor cell expansion and to suppress their differentiation into neurons or glia. ATF5 expression is down-regulated by trophic factors and this is required for their capacity to promote neuroprogenitor cell cycle exit and differentiation into either neurons, oligodendroglia or astrocytes. ATF5 is also highly expressed in a number of tumor types, including neural tumors such as neuroblastomas, medulloblastomas and glioblastomas. Examination of the role of ATF5 in glioblastoma cells indicates that interference with its expression or activity causes them to undergo apoptotic death. In contrast, normal astrocytes and neurons do not appear to require ATF5 for survival, indicating that it may be a selective target for treatment of glioblastomas and other neural neoplasias. Further studies are needed to identify the transcriptional targets of ATF5 and the mechanisms by which its expression is regulated in neuroprogenitors and tumors.
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Affiliation(s)
- Lloyd A Greene
- Department of Pathology and Cell Biology Columbia University College of Physicians and Surgeons, New York, New York 10032, USA.
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30
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Krige D, Needham LA, Bawden LJ, Flores N, Farmer H, Miles LEC, Stone E, Callaghan J, Chandler S, Clark VL, Kirwin-Jones P, Legris V, Owen J, Patel T, Wood S, Box G, Laber D, Odedra R, Wright A, Wood LM, Eccles SA, Bone EA, Ayscough A, Drummond AH. CHR-2797: an antiproliferative aminopeptidase inhibitor that leads to amino acid deprivation in human leukemic cells. Cancer Res 2008; 68:6669-79. [PMID: 18701491 DOI: 10.1158/0008-5472.can-07-6627] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
CHR-2797 is a novel metalloenzyme inhibitor that is converted into a pharmacologically active acid product (CHR-79888) inside cells. CHR-79888 is a potent inhibitor of a number of intracellular aminopeptidases, including leucine aminopeptidase. CHR-2797 exerts antiproliferative effects against a range of tumor cell lines in vitro and in vivo and shows selectivity for transformed over nontransformed cells. Its antiproliferative effects are at least 300 times more potent than the prototypical aminopeptidase inhibitor, bestatin. However, the mechanism by which inhibition of these enzymes leads to proliferative changes is not understood. Gene expression microarrays were used to profile changes in mRNA expression levels in the human promyelocytic leukemia cell line HL-60 treated with CHR-2797. This analysis showed that CHR-2797 treatment induced a transcriptional response indicative of amino acid depletion, the amino acid deprivation response, which involves up-regulation of amino acid synthetic genes, transporters, and tRNA synthetases. These changes were confirmed in other leukemic cell lines sensitive to the antiproliferative effects of CHR-2797. Furthermore, CHR-2797 treatment inhibited phosphorylation of mTOR substrates and reduced protein synthesis in HL-60 cells, both also indicative of amino acid depletion. Treatment with CHR-2797 led to an increase in the concentration of intracellular small peptides, the substrates of aminopeptidases. It is suggested that aminopeptidase inhibitors, such as CHR-2797 and bestatin, deplete sensitive tumor cells of amino acids by blocking protein recycling, and this generates an antiproliferative effect. CHR-2797 is orally bioavailable and currently undergoing phase II clinical investigation in the treatment of myeloid leukemia.
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Affiliation(s)
- David Krige
- Chroma Therapeutics Ltd., Abingdon, United Kingdom.
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Pascual M, Gómez-Lechón MJ, Castell JV, Jover R. ATF5 Is a Highly Abundant Liver-Enriched Transcription Factor that Cooperates with Constitutive Androstane Receptor in the Transactivation of CYP2B6: Implications in Hepatic Stress Responses. Drug Metab Dispos 2008; 36:1063-72. [DOI: 10.1124/dmd.107.019380] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Abstract
The DISC locus is located at the breakpoint of a balanced t(1;11) chromosomal translocation in a large and unique Scottish family. This translocation segregates in a highly statistically significant manner with a broad diagnosis of psychiatric illness, including schizophrenia, bipolar disorder and major depression, as well as with a narrow diagnosis of schizophrenia alone. Two novel genes were identified at this locus and due to the high prevalence of schizophrenia in this family, they were named Disrupted-in-Schizophrenia-1 (DISC1) and Disrupted-in-Schizophrenia-2 (DISC2). DISC1 encodes a novel multifunctional scaffold protein, whereas DISC2 is a putative noncoding RNA gene antisense to DISC1. A number of independent genetic linkage and association studies in diverse populations support the original linkage findings in the Scottish family and genetic evidence now implicates the DISC locus in susceptibility to schizophrenia, schizoaffective disorder, bipolar disorder and major depression as well as various cognitive traits. Despite this, with the exception of the t(1;11) translocation, robust evidence for a functional variant(s) is still lacking and genetic heterogeneity is likely. Of the two genes identified at this locus, DISC1 has been prioritized as the most probable candidate susceptibility gene for psychiatric illness, as its protein sequence is directly disrupted by the translocation. Much research has been undertaken in recent years to elucidate the biological functions of the DISC1 protein and to further our understanding of how it contributes to the pathogenesis of schizophrenia. These data are the main subject of this review; however, the potential involvement of DISC2 in the pathogenesis of psychiatric illness is also discussed. A detailed picture of DISC1 function is now emerging, which encompasses roles in neurodevelopment, cytoskeletal function and cAMP signalling, and several DISC1 interactors have also been defined as independent genetic susceptibility factors for psychiatric illness. DISC1 is a hub protein in a multidimensional risk pathway for major mental illness, and studies of this pathway are opening up opportunities for a better understanding of causality and possible mechanisms of intervention.
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Affiliation(s)
- J E Chubb
- Medical Genetics Section, The Centre for Molecular Medicine, Western General Hospital, The University of Edinburgh, Edinburgh, UK
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Watatani Y, Ichikawa K, Nakanishi N, Fujimoto M, Takeda H, Kimura N, Hirose H, Takahashi S, Takahashi Y. Stress-induced translation of ATF5 mRNA is regulated by the 5'-untranslated region. J Biol Chem 2007; 283:2543-53. [PMID: 18055463 DOI: 10.1074/jbc.m707781200] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Activating transcription factor (ATF) 5 is a transcription factor belonging to the ATF/cAMP-response element-binding protein gene family. We previously reported that ATF5 mRNA expression increased in response to amino acid limitation. The ATF5 gene allows transcription of mRNAs with at least two alternative 5'-untranslated regions (5'-UTRs), 5'-UTRalpha and 5'-UTRbeta, derived from exon1alpha and exon1beta. 5'-UTRalpha contains highly conserved sequences, in which the upstream open reading frames (uORFs) uORF1 and uORF2 are found in many species. This study was designed to investigate the potential role of 5'-UTRs in translational control. These 5'-UTRs differentially determined translation efficiency from mRNA. The presence of 5'-UTRalpha or 5'-UTRbeta represses translation from the downstream ATF5 ORF. Moreover, 5'-UTRalpha-regulated translational repression is released by amino acid limitation or NaAsO(2) exposure. This release was not seen for 5'-UTRbeta. Mutation of uAUG2 in the uORF2 of 5'-UTRalpha restored the basal expression and abolished the positive regulation by amino acid limitation or arsenite exposure. We demonstrated that phosphorylation of eukaryotic initiation factor 2alpha was required for amino acid limitation-induced translational regulation of ATF5. Furthermore, arsenite exposure activated the exogenously expressed heme-regulated inhibitor kinase and induced the phosphorylation of eukaryotic initiation factor 2alpha in nonerythroid cells. These results suggest that translation of ATF5 is regulated by the alternative 5'-UTR region of its mRNA, and ATF5 may play a role in protecting cells from amino acid limitation or arsenite-induced oxidative stress.
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Affiliation(s)
- Yujiro Watatani
- Laboratory of Environmental Molecular Physiology, School of Life Science, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, Japan
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Nishikawa T, Tomiya T, Ohtomo N, Inoue Y, Ikeda H, Tejima K, Watanabe N, Tanoue Y, Omata M, Fujiwara K. Stimulation by glutamine and proline of HGF production in hepatic stellate cells. Biochem Biophys Res Commun 2007; 363:978-82. [DOI: 10.1016/j.bbrc.2007.09.082] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2007] [Accepted: 09/20/2007] [Indexed: 12/15/2022]
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