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Hamad HA, Enezei HH, Alrawas A, Zakuan NM, Abdullah NA, Cheah YK, Hashim NFM. Identification of Potential Chemical Substrates as Fuel for Hypoxic Tumors That May Be Linked to Invadopodium Formation in Hypoxia-Induced MDA-MB-231 Breast-Cancer Cell Line. Molecules 2020; 25:E3876. [PMID: 32858793 PMCID: PMC7503683 DOI: 10.3390/molecules25173876] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 07/17/2020] [Accepted: 07/23/2020] [Indexed: 12/24/2022] Open
Abstract
Hypoxia plays a significant role in solid tumors by the increased expression of hypoxia-inducible factor-1α (HIF-1α), which is known to promote cancer invasion and metastasis. Cancer-cell invasion dynamically begins with the degradation of the extracellular matrix (ECM) via invadopodia formation. The chemical substrates that are utilized by hypoxic cells as fuel to drive invadopodia formation are still not fully understood. Therefore, the aim of the study was to maintain MDA-MB-231 cells under hypoxia conditions to allow cells to form a large number of invadopodia as a model, followed by identifying their nutrient utilization. The results of the study revealed an increase in the number of cells forming invadopodia under hypoxia conditions. Moreover, Western blot analysis confirmed that essential proteins for hypoxia and invadopodia, including HIF-1α, vascular endothelial growth factor (VEGF), metallopeptidase-2 (MMP-2), and Rho guanine nucleotide exchange factor 7 (β-PIX), significantly increased under hypoxia. Interestingly, phenotype microarray showed that only 11 chemical substrates from 367 types of substrates were significantly metabolized in hypoxia compared to in normoxia. This is thought to be fuel for hypoxia to drive the invasion process. In conclusion, we found 11 chemical substrates that could have potential energy sources for hypoxia-induced invadopodia formation of these cells. This may in part be a target in the hypoxic tumor and invadopodia formation. Additionally, these findings can be used as potential carrier targets in cancer-drug discovery, such as the usage of dextrin.
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Affiliation(s)
- Hamad Ali Hamad
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43300, Malaysia; (H.A.H.); (A.A.); (N.A.A.); (Y.K.C.)
- Research and Training Unit, Anbar Cancer Centre, Anbar Health Directorate, Ramadi 31001, Iraq
| | - Hamid Hammad Enezei
- Department of Oral and Maxillofacial Surgery, Collage of Dentistry, Anbar University, Ramadi 31001, Iraq;
| | - Anmar Alrawas
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43300, Malaysia; (H.A.H.); (A.A.); (N.A.A.); (Y.K.C.)
| | - Noraina Muhamad Zakuan
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43300, Malaysia; (H.A.H.); (A.A.); (N.A.A.); (Y.K.C.)
| | - Nurul Akmaryanti Abdullah
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43300, Malaysia; (H.A.H.); (A.A.); (N.A.A.); (Y.K.C.)
| | - Yoke Kqueen Cheah
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43300, Malaysia; (H.A.H.); (A.A.); (N.A.A.); (Y.K.C.)
| | - Nur Fariesha Md Hashim
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43300, Malaysia; (H.A.H.); (A.A.); (N.A.A.); (Y.K.C.)
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2
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Wang CW, Purkayastha A, Jones KT, Thaker SK, Banerjee U. In vivo genetic dissection of tumor growth and the Warburg effect. eLife 2016; 5. [PMID: 27585295 PMCID: PMC5030086 DOI: 10.7554/elife.18126] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 08/31/2016] [Indexed: 12/18/2022] Open
Abstract
A well-characterized metabolic landmark for aggressive cancers is the reprogramming from oxidative phosphorylation to aerobic glycolysis, referred to as the Warburg effect. Models mimicking this process are often incomplete due to genetic complexities of tumors and cell lines containing unmapped collaborating mutations. In order to establish a system where individual components of oncogenic signals and metabolic pathways can be readily elucidated, we induced a glycolytic tumor in the Drosophila wing imaginal disc by activating the oncogene PDGF/VEGF-receptor (Pvr). This causes activation of multiple oncogenic pathways including Ras, PI3K/Akt, Raf/ERK, Src and JNK. Together this network of genes stabilizes Hifα (Sima) that in turn, transcriptionally up-regulates many genes encoding glycolytic enzymes. Collectively, this network of genes also causes inhibition of pyruvate dehydrogenase (PDH) activity resulting in diminished ox-phos levels. The high ROS produced during this process functions as a feedback signal to consolidate this metabolic reprogramming.
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Affiliation(s)
- Cheng-Wei Wang
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
| | - Arunima Purkayastha
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
| | - Kevin T Jones
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
| | - Shivani K Thaker
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
| | - Utpal Banerjee
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States.,Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, United States.,Molecular Biology Institute, University of California, Los Angeles, Los Angeles, United States.,Broad Stem Cell Research Center, University of California, Los Angeles, Los Angeles, United States
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3
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Wang L, González S, Dai W, Deng S, Lu L. Effect of Hypoxia-regulated Polo-like Kinase 3 (Plk3) on Human Limbal Stem Cell Differentiation. J Biol Chem 2016; 291:16519-29. [PMID: 27281822 DOI: 10.1074/jbc.m116.725747] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Indexed: 11/06/2022] Open
Abstract
Hypoxic conditions in the cornea affect epithelial function by activating Polo-like kinase 3 (Plk3) signaling and the c-Jun·AP-1 transcription complex, resulting in apoptosis of corneal epithelial cells. Hypoxic stress in the culture conditions also regulates limbal stem cell growth and fate. In this study, we demonstrate that there is a differential response of Plk3 in hypoxic stress-induced primary human limbal stem (HLS) and corneal epithelial (HCE) cells, resulting in different pathways of cell fate. We found that hypoxic stress induced HLS cell differentiation by down-regulating Plk3 activity at the transcription level, which was opposite to the effect of hypoxic stress on Plk3 activation to elicit HCE cell apoptosis, detected by DNA fragmentation and TUNEL assays. Hypoxic stress-induced increases in c-Jun phosphorylation/activation were not observed in HLS cells because Plk3 expression and activity were suppressed in hypoxia-induced HLS cells. Instead, hypoxic stress-induced HLS cell differentiation was monitored by cell cycle analysis and measured by the decrease and increase in p63 and keratin 12 expression, respectively. Hypoxic stress-induced Plk3 signaling to regulate c-Jun activity, resulting in limbal stem cell differentiation and center epithelial apoptosis, was also found in the corneas of wild-type and Plk3(-/-)-deficient mice. Our results, for the first time, reveal the differential effects of hypoxic stress on Plk3 activity in HLS and HCE cells. Instead of apoptosis, hypoxic stress suppresses Plk3 activity to protect limbal stem cells from death and to allow the process of HLS cell differentiation.
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Affiliation(s)
- Ling Wang
- From the Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Torrance, California 90502
| | - Sheyla González
- the Department of Ophthalmology, Julie Stein Eye Institute, David Geffen School of Medicine, University of California, Los Angeles, California 91020, and
| | - Wei Dai
- the Department of Environmental Medicine, New York University School of Medicine, Tuxedo, New York 10987
| | - Sophie Deng
- the Department of Ophthalmology, Julie Stein Eye Institute, David Geffen School of Medicine, University of California, Los Angeles, California 91020, and
| | - Luo Lu
- From the Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Torrance, California 90502,
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4
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Laderoute KR, Calaoagan JM, Chao WR, Dinh D, Denko N, Duellman S, Kalra J, Liu X, Papandreou I, Sambucetti L, Boros LG. 5'-AMP-activated protein kinase (AMPK) supports the growth of aggressive experimental human breast cancer tumors. J Biol Chem 2014; 289:22850-22864. [PMID: 24993821 PMCID: PMC4132788 DOI: 10.1074/jbc.m114.576371] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 06/20/2014] [Indexed: 12/18/2022] Open
Abstract
Rapid tumor growth can establish metabolically stressed microenvironments that activate 5'-AMP-activated protein kinase (AMPK), a ubiquitous regulator of ATP homeostasis. Previously, we investigated the importance of AMPK for the growth of experimental tumors prepared from HRAS-transformed mouse embryo fibroblasts and for primary brain tumor development in a rat model of neurocarcinogenesis. Here, we used triple-negative human breast cancer cells in which AMPK activity had been knocked down to investigate the contribution of AMPK to experimental tumor growth and core glucose metabolism. We found that AMPK supports the growth of fast-growing orthotopic tumors prepared from MDA-MB-231 and DU4475 breast cancer cells but had no effect on the proliferation or survival of these cells in culture. We used in vitro and in vivo metabolic profiling with [(13)C]glucose tracers to investigate the contribution of AMPK to core glucose metabolism in MDA-MB-231 cells, which have a Warburg metabolic phenotype; these experiments indicated that AMPK supports tumor glucose metabolism in part through positive regulation of glycolysis and the nonoxidative pentose phosphate cycle. We also found that AMPK activity in the MDA-MB-231 tumors could systemically perturb glucose homeostasis in sensitive normal tissues (liver and pancreas). Overall, our findings suggest that the contribution of AMPK to the growth of aggressive experimental tumors has a critical microenvironmental component that involves specific regulation of core glucose metabolism.
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Affiliation(s)
- Keith R Laderoute
- Biosciences Division, SRI International, Menlo Park, California 94025,.
| | - Joy M Calaoagan
- Biosciences Division, SRI International, Menlo Park, California 94025
| | - Wan-Ru Chao
- Biosciences Division, SRI International, Menlo Park, California 94025
| | - Dominc Dinh
- Biosciences Division, SRI International, Menlo Park, California 94025
| | - Nicholas Denko
- Department of Radiation Oncology, The James Comprehensive Cancer Center, Ohio State University, Columbus, Ohio 43210
| | - Sarah Duellman
- Biosciences Division, SRI International, Menlo Park, California 94025
| | - Jessica Kalra
- Department of Biology, Langara College, Vancouver, British Columbia V5W 2Z6, Canada
| | - Xiaohe Liu
- Biosciences Division, SRI International, Menlo Park, California 94025
| | - Ioanna Papandreou
- Department of Radiation Oncology, The James Comprehensive Cancer Center, Ohio State University, Columbus, Ohio 43210
| | - Lidia Sambucetti
- Biosciences Division, SRI International, Menlo Park, California 94025
| | - Laszlo G Boros
- Department of Pediatrics, UCLA School of Medicine, Los Angeles, California 90509,; Los Angeles Biomedical Research Institute at the Harbor-UCLA Medical Center, Torrance, California 90502, and; SIDMAP, LLC, Los Angeles, California 90064
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5
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Li H, Lee J, He C, Zou MH, Xie Z. Suppression of the mTORC1/STAT3/Notch1 pathway by activated AMPK prevents hepatic insulin resistance induced by excess amino acids. Am J Physiol Endocrinol Metab 2014; 306:E197-209. [PMID: 24302004 PMCID: PMC3920006 DOI: 10.1152/ajpendo.00202.2013] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Nutrient overload is associated with the development of obesity, insulin resistance, and type 2 diabetes. However, the underlying mechanisms for developing insulin resistance in the presence of excess nutrients are incompletely understood. We investigated whether activation of AMP-activated protein kinase (AMPK) prevents the hepatic insulin resistance that is induced by the consumption of a high-protein diet (HPD) and the presence of excess amino acids. Exposure of HepG2 cells to excess amino acids reduced AMPK phosphorylation, upregulated Notch1 expression, and impaired the insulin-stimulated phosphorylation of Akt Ser(473) and insulin receptor substrate-1 (IRS-1) Tyr(612). Inhibition of Notch1 prevented amino acid-induced insulin resistance, which was accompanied by reduced expression of Rbp-Jk, hairy and enhancer of split-1, and forkhead box O1. Mechanistically, mTORC1 signaling was activated by excess amino acids, which then positively regulated Notch1 expression through the activation of the signal transducer and activator of transcription 3 (STAT3). Activation of AMPK by metformin inhibited mTORC1-STAT3 signaling, thereby preventing excess amino acid-impaired insulin signaling. Finally, HPD feeding suppressed AMPK activity, activated mTORC1/STAT3/Notch1 signaling, and induced insulin resistance. Chronic administration of either metformin or rapamycin inhibited the HPD-activated mTORC1/STAT3/Notch1 signaling pathway and prevented hepatic insulin resistance. We conclude that the upregulation of Notch1 expression by hyperactive mTORC1 signaling is an essential event in the development of hepatic insulin resistance in the presence of excess amino acids. Activation of AMPK prevents amino acid-induced insulin resistance through the suppression of the mTORC1/STAT3/Notch1 signaling pathway.
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Affiliation(s)
- Hongliang Li
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
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6
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Lu J, Wang L, Dai W, Lu L. Effect of hypoxic stress-activated Polo-like kinase 3 on corneal epithelial wound healing. Invest Ophthalmol Vis Sci 2010; 51:5034-40. [PMID: 20505196 DOI: 10.1167/iovs.10-5501] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
PURPOSE Hypoxia/reoxygenation conditions can generate oxidative stresses resulting in the suppression of cell proliferation and the delay of corneal epithelial wound healing. The purpose of this study was to investigate the cellular mechanism involving the role of the stress-responsive Polo-like kinase 3 (Plk3) in hypoxic stress-induced delay of corneal epithelial wound healing. METHODS Plk3 activities were determined by immunochemistry and immunocomplex kinase assay approaches. Corneal epithelial wound healing was evaluated by a whole-eye organ culture model and by scratch-induced wound closure assay. Corneal epithelial layer was removed by using a corneal rust-ring-remover in wild-type and Plk3(-/-) mice. Wound healing was analyzed using a confocal imaging system. Cell growth was measured by MTT assays. RESULTS The effect of hypoxic stress on early stages of corneal epithelial wound healing was compared with other oxidative stresses, including UV, CoCl(2), and H(2)O(2) treatments. Hypoxic stress-induced delay of corneal epithelial wound healing was further evaluated in human corneal epithelial cells and in the corneas of wild-type and Plk3 knockout (Plk3(-/-)) mice. Hypoxic stress-induced Plk3 activation resulted in growth attenuation and delay of wound healing. Further evidence demonstrated that the increase in Plk3 activity in constitutively active Plk3-expressed cells significantly enhanced stress-induced delay of wound healing. In contrast, hypoxic stress-induced delay of wound healing was markedly diminished in the corneas of Plk3 deficient Plk3(-/-) mice. CONCLUSIONS These results provide for the first time important evidence that Plk3 plays a significant role in hypoxic stress-induced attenuation of cell growth and delay of corneal epithelial wound healing.
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Affiliation(s)
- Jiawei Lu
- Division of Molecular Medicine, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Torrance, California 90502, USA
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7
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Yu B, Miao ZH, Jiang Y, Li MH, Yang N, Li T, Ding J. c-Jun Protects Hypoxia-Inducible Factor-1α from Degradation via Its Oxygen-Dependent Degradation Domain in a Nontranscriptional Manner. Cancer Res 2009; 69:7704-12. [DOI: 10.1158/0008-5472.can-09-0808] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Although hypoxia-inducible factor-1α (HIF-1α) has long been intensively investigated as a drug target by interfering with its expression or transcriptional function, the regulatory mechanisms of HIF-1α remain to be further clarified. We report here that c-Jun associates with HIF-1α via its oxygen-dependent degradation domain, masks the sites for ubiquitination, and thus protects HIF-1α from proteasome-executing degradation. All of these together resulted in the stabilization and accumulation of HIF-1α, consequently promoting the transcription of its target gene and driving angiogenesis-related events. The stabilization of HIF-1α was dependent on the domains of c-Jun for DNA binding and heterodimerization but independent of the Ser63/73 phosphorylation that is critical for transcriptional function. These findings highlight a previously unrecognized nontranscriptional function of c-Jun on the one hand and a distinct regulatory mechanism of HIF-1α activity on the other, consequently offering profound mechanistic insights into multiple events simultaneously involving both c-Jun and HIF-1α in tumor progression. [Cancer Res 2009;69(19):7704–12]
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Affiliation(s)
- Bing Yu
- Division of Antitumor Pharmacology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, People's Republic of China
| | - Ze-Hong Miao
- Division of Antitumor Pharmacology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, People's Republic of China
| | - Yi Jiang
- Division of Antitumor Pharmacology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, People's Republic of China
| | - Mei-Hong Li
- Division of Antitumor Pharmacology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, People's Republic of China
| | - Na Yang
- Division of Antitumor Pharmacology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, People's Republic of China
| | - Ting Li
- Division of Antitumor Pharmacology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, People's Republic of China
| | - Jian Ding
- Division of Antitumor Pharmacology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, People's Republic of China
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8
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Garedew A, Kämmerer U, Singer D. Respiratory response of malignant and placental cells to changes in oxygen concentration. Respir Physiol Neurobiol 2008; 165:154-60. [PMID: 19041734 DOI: 10.1016/j.resp.2008.11.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Revised: 10/26/2008] [Accepted: 11/03/2008] [Indexed: 10/21/2022]
Abstract
Malignant cells and foetal tissues are exposed to low oxygen partial pressure (pO2) in situ due to the limited supply of oxygenated blood. Whether these cells have adapted to low pO2 or live under constant constraint is not clear. Herein, we compared the respiratory responses of different malignant cell types, maternal and foetal placental leucocytes, and benign cells by incubating them under a gradient of pO2, from saturation to hypoxia, in a high resolution respirometer. The malignant cells and foetal leucocytes showed higher rates of mitochondrial oxygen uptake compared to the benign cells and maternal leucocytes, respectively. On the other hand, the mitochondrial oxygen uptake rates of the hypoxia adapted cells declined faster than the other cell types during the onset of hypoxia, probably suggesting conformance of aerobic metabolism to the local oxygen concentration. The O2 consumption rate per million cells (JO2) of the malignant cells declined only when the O2 concentration ([O2]) decreased to values<or=10 microM. On the other hand, the JO2 of the benign cells declined with the decrease in [O2] from 200 to 40 microM and <or=10 microM. In the [O2] ranges outside these values the JO2 remained constant regardless of the decline of [O2] in the medium. The JO2 of foetal leucocytes and malignant cells responded to the change in [O2] in a similar manner, and may indicate comparable mechanisms of adaptation to hypoxia.
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Affiliation(s)
- Assegid Garedew
- Department of Obstetrics & Gynaecology, University of Würzburg, Germany.
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9
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Wang L, Gao J, Dai W, Lu L. Activation of Polo-like kinase 3 by hypoxic stresses. J Biol Chem 2008; 283:25928-35. [PMID: 18650425 DOI: 10.1074/jbc.m801326200] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Hypoxia/reoxygenation stress induces the activation of specific signaling proteins and activator protein 1 (AP-1) to regulate cell cycle regression and apoptosis. In the present study, we report that hypoxia/reoxygenation stress activates AP-1 by increasing c-Jun phosphorylation and DNA binding activity through activation of Polo-like-kinase 3 (Plk3) resulting in apoptosis. The specific effect of hypoxia/reoxygenation stress on Plk3 activation resulting in c-Jun phosphorylation was the opposite of UV irradiation-induced responses that are meanly independent on activation of the stress-induced JNK signaling pathway in human corneal epithelial (HCE) cells. The effect of hypoxia/reoxygenation stress-induced Plk3 activation on increased c-Jun phosphorylation and apoptosis was also mimicked by exposure of cells to CoCl(2). Hypoxia/reoxygenation activated Plk3 in HCE cells to directly phosphorylate c-Jun proteins at phosphorylation sites Ser-63 and Ser-73, and to increase DNA binding activity of c-Jun, detected by EMSA. Further evidence demonstrated that Plk3 and phospho-c-Jun were immunocolocalized in the nuclear compartment of hypoxia/reoxygenation stress-induced cells. Increased Plk3 activity by overexpression of wild-type and dominantly positive Plk3 enhanced the effect of hypoxia/reoxygenation on c-Jun phosphorylation and cell death. In contrast, knocking-down Plk3 mRNA suppressed hypoxia-induced c-Jun phosphorylation. Our results provide a new mechanism indicating that hypoxia/reoxygenation induces Plk3 activation instead of the JNK effect to directly phosphorylate and activate c-Jun, subsequently contributing to apoptosis in HCE cells.
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Affiliation(s)
- Ling Wang
- Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Torrance, California 90502, USA
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10
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Murphy BJ, Kimura T, Sato BG, Shi Y, Andrews GK. Metallothionein induction by hypoxia involves cooperative interactions between metal-responsive transcription factor-1 and hypoxia-inducible transcription factor-1alpha. Mol Cancer Res 2008; 6:483-90. [PMID: 18337454 DOI: 10.1158/1541-7786.mcr-07-0341] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Mammalian metallothionein (MT) genes are transcriptionally activated by the essential metal zinc as well as by environmental stresses, including toxic metal overload and redox fluctuations. In addition to playing a key role in zinc homeostasis, MT proteins can protect against metal- and oxidant-induced cellular damage, and may participate in other fundamental physiologic and pathologic processes such as cell survival, proliferation, and neoplasia. Previously, our group reported a requirement for metal-responsive transcription factor-1 (MTF-1) in hypoxia-induced transcription of mouse MT-I and human MT-IIA genes. Here, we provide evidence that the protumorigenic hypoxia-inducible transcription factor-1alpha (HIF-1alpha) is essential for induction of MT-1 by hypoxia, but not zinc. Chromatin immunoprecipitation assays revealed that MTF-1 and HIF-1alpha are both recruited to the mouse MT-I promoter in response to hypoxia, but not zinc. In the absence of HIF-1alpha, MTF-1 is recruited to the MT-I promoter but fails to activate MT-I gene expression in response to hypoxia. Thus, HIF-1alpha seems to function as a coactivator of MT-I gene transcription by interacting with MTF-1 during hypoxia. Coimmunoprecipitation studies suggest interaction between MTF-1 and HIF-1alpha, either directly or as mediated by other factors. It is proposed that association of these important transcription factors in a multiprotein complex represents a common strategy to control unique sets of hypoxia-inducible genes in both normal and diseased tissue.
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Affiliation(s)
- Brian J Murphy
- Biosciences Division, SRI International, Menlo Park, CA 94025, USA.
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11
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Laderoute KR, Amin K, Calaoagan JM, Knapp M, Le T, Orduna J, Foretz M, Viollet B. 5'-AMP-activated protein kinase (AMPK) is induced by low-oxygen and glucose deprivation conditions found in solid-tumor microenvironments. Mol Cell Biol 2006; 26:5336-47. [PMID: 16809770 PMCID: PMC1592699 DOI: 10.1128/mcb.00166-06] [Citation(s) in RCA: 352] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Low oxygen gradients (hypoxia and anoxia) are important determinants of pathological conditions under which the tissue blood supply is deficient or defective, such as in solid tumors. We have been investigating the relationship between the activation of hypoxia-inducible factor 1 (HIF-1), the primary transcriptional regulator of the mammalian response to hypoxia, and 5'-AMP-activated protein kinase (AMPK), another regulatory system important for controlling cellular energy metabolism. In the present study, we used mouse embryo fibroblasts nullizygous for HIF-1alpha or AMPK expression to show that AMPK is rapidly activated in vitro by both physiological and pathophysiological low-oxygen conditions, independently of HIF-1 activity. These findings imply that HIF-1 and AMPK are components of a concerted cellular response to maintain energy homeostasis in low-oxygen or ischemic-tissue microenvironments. Finally, we used transformed derivatives of wild-type and HIF-1alpha- or AMPKalpha-null mouse embryo fibroblasts to determine whether AMPK is activated in vivo. We obtained evidence that AMPK is activated in authentic hypoxic tumor microenvironments and that this activity overlaps with regions of hypoxia detected by a chemical probe. We also showed that AMPK is important for the growth of this tumor model.
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MESH Headings
- AMP-Activated Protein Kinases
- Acetyl-CoA Carboxylase/metabolism
- Adenosine Triphosphate/metabolism
- Animals
- Cells, Cultured
- Enzyme Activation
- Female
- Genes, ras
- Glucose/metabolism
- Hypoxia/enzymology
- Hypoxia-Inducible Factor 1, alpha Subunit/deficiency
- Hypoxia-Inducible Factor 1, alpha Subunit/genetics
- Hypoxia-Inducible Factor 1, alpha Subunit/metabolism
- Mice
- Mice, Inbred BALB C
- Mice, Knockout
- Mice, Nude
- Multienzyme Complexes/deficiency
- Multienzyme Complexes/genetics
- Multienzyme Complexes/metabolism
- Neoplasms, Experimental/enzymology
- Neoplasms, Experimental/genetics
- Neoplasms, Experimental/metabolism
- Phosphorylation
- Protein Serine-Threonine Kinases/deficiency
- Protein Serine-Threonine Kinases/genetics
- Protein Serine-Threonine Kinases/metabolism
- Transformation, Genetic
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Affiliation(s)
- Keith R Laderoute
- SRI International, Bldg. L, Rm. A258, 333 Ravenswood Ave., Menlo Park, CA 94025, USA.
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12
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Harpster MH, Bandyopadhyay S, Thomas DP, Ivanov PS, Keele JA, Pineguina N, Gao B, Amarendran V, Gomelsky M, McCormick RJ, Stayton MM. Earliest changes in the left ventricular transcriptome postmyocardial infarction. Mamm Genome 2006; 17:701-15. [PMID: 16845475 DOI: 10.1007/s00335-005-0120-1] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2005] [Accepted: 02/15/2006] [Indexed: 01/06/2023]
Abstract
We report a genome-wide survey of early responses of the mouse heart transcriptome to acute myocardial infarction (AMI). For three regions of the left ventricle (LV), namely, ischemic/infarcted tissue (IF), the surviving LV free wall (FW), and the interventricular septum (IVS), 36,899 transcripts were assayed at six time points from 15 min to 48 h post-AMI in both AMI and sham surgery mice. For each transcript, temporal expression patterns were systematically compared between AMI and sham groups, which identified 515 AMI-responsive genes in IF tissue, 35 in the FW, 7 in the IVS, with three genes induced in all three regions. Using the literature, we assigned functional annotations to all 519 nonredundant AMI-induced genes and present two testable models for central signaling pathways induced early post-AMI. First, the early induction of 15 genes involved in assembly and activation of the activator protein-1 (AP-1) family of transcription factors implicates AP-1 as a dominant regulator of earliest post-ischemic molecular events. Second, dramatic increases in transcripts for arginase 1 (ARG1), the enzymes of polyamine biosynthesis, and protein inhibitor of nitric oxide synthase (NOS) activity indicate that NO production may be regulated, in part, by inhibition of NOS and coordinate depletion of the NOS substrate, L: -arginine. ARG1: was the single-most highly induced transcript in the database (121-fold in IF region) and its induction in heart has not been previously reported.
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Affiliation(s)
- Mark H Harpster
- Department of Molecular Biology, University of Wyoming, Laramie, 82071, USA
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13
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Mense SM, Sengupta A, Zhou M, Lan C, Bentsman G, Volsky DJ, Zhang L. Gene expression profiling reveals the profound upregulation of hypoxia-responsive genes in primary human astrocytes. Physiol Genomics 2006; 25:435-49. [PMID: 16507782 DOI: 10.1152/physiolgenomics.00315.2005] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Oxygen is vital for the development and survival of mammals. In response to hypoxia, the brain initiates numerous adaptive responses at the organ level as well as at the molecular and cellular levels, including the alteration of gene expression. Astrocytes play critical roles in the proper functioning of the brain; thus the manner in which astrocytes respond to hypoxia is likely important in determining the outcome of brain hypoxia. Here, we used microarray gene expression profiling and data-analysis algorithms to identify and analyze hypoxia-responsive genes in primary human astrocytes. We also compared gene expression patterns in astrocytes with those in human HeLa cells and pulmonary artery endothelial cells (ECs). Remarkably, in astrocytes, five times as many genes were induced as suppressed, whereas in HeLa and pulmonary ECs, as many as or more genes were suppressed than induced. More genes encoding hypoxia-inducible functions, such as glycolytic enzymes and angiogenic growth factors, were strongly induced in astrocytes compared with HeLa cells. Furthermore, gene ontology and computational algorithms revealed that many target genes of the EGF and insulin signaling pathways and the transcriptional regulators Myc, Jun, and p53 were selectively altered by hypoxia in astrocytes. Indeed, Western blot analysis confirmed that two major signal transducers mediating insulin and EGF action, Akt and MEK1/2, were activated by hypoxia in astrocytes. These results provide a global view of the signaling and regulatory network mediating oxygen regulation in human astrocytes.
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Affiliation(s)
- S M Mense
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York 10032, USA
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14
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Liu H, Zheng F, Cao Q, Ren B, Zhu L, Striker G, Vlassara H. Amelioration of oxidant stress by the defensin lysozyme. Am J Physiol Endocrinol Metab 2006; 290:E824-32. [PMID: 16317028 DOI: 10.1152/ajpendo.00349.2005] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Reactive oxidant species (ROS), products of normal metabolism, cause oxidant injury if they accumulate in pathological amounts. Lysozyme (LZ) contains an 18-amino acid domain that binds agents such as advanced glycation end products (AGE) that generate ROS. We examined whether endogenous LZ affected physiological, or baseline, antioxidant balance and provided protection against both acute and chronic oxidant injury, using paraquat and H2O2 as agents of acute injury and AGE for chronic injury. Hen egg LZ-Tg mice had threefold higher serum LZ levels and decreased baseline AGE levels in serum and liver. These findings were linked to an enhanced baseline systemic GSH-to-GSSG ratio. Baseline levels of stress response genes p66(Shc) and c-Jun were also lower in liver tissue of LZ-Tg mice. Survival from severe oxidant injury induced by paraquat was twofold greater in LZ-Tg mice. In addition, LZ-Tg mice were resistant to chronic exogenous oxidant stress (OS) induced by AGE administration. Preincubation of hepatocytes (Hep G2) with LZ suppressed redox balance at baseline, as well as OS after added paraquat, AGE, or H2O2. LZ also ameliorated paraquat-enhanced cell apoptosis in a dose-dependent manner and suppressed AGE-induced p66(Shc) expression and c-Jun phosphorylation in Hep G2 cells. Thus LZ provides protection against acute and chronic oxidant injury by mechanisms involving suppression of ROS generation and of OS response genes.
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Affiliation(s)
- Huixian Liu
- Department of Geriatrics, Mount Sinai School of Medicine, One Gustave Levy Place, New York, NY 10029, USA
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15
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Koritzinsky M, Seigneuric R, Magagnin MG, van den Beucken T, Lambin P, Wouters BG. The hypoxic proteome is influenced by gene-specific changes in mRNA translation. Radiother Oncol 2006; 76:177-86. [PMID: 16098621 DOI: 10.1016/j.radonc.2005.06.036] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2005] [Revised: 05/24/2005] [Accepted: 06/21/2005] [Indexed: 10/25/2022]
Abstract
BACKGROUND AND PURPOSE Hypoxia causes a rapid reduction in mRNA translation efficiency. This inhibition does not affect all mRNA species to the same extent and can therefore contribute significantly to hypoxia-induced differential protein expression. Our aim in this study was to characterize changes in gene expression during acute hypoxia and evaluate the contribution of regulation via mRNA translation on these changes. For each gene, the contribution of changes in mRNA abundance versus mRNA translation was determined. MATERIALS AND METHODS DU145 prostate carcinoma cells were exposed to 4h of hypoxia (<0.02% O2). Efficiently translated mRNAs were isolated by sedimentation through a sucrose gradient. Affymetrix microarray technology was used to evaluate both the transcriptional and translational contribution to gene expression. Results were validated by quantitative PCR. RESULTS One hundred and twenty genes were more than 4-fold upregulated by hypoxia in the efficiently translated fraction of mRNA, in comparison to only 76 genes at the level of transcription. Of the 50 genes demonstrating the largest changes in translation, 11 were found to be more than 2-fold over represented in the translated fraction in comparison to their overall transcriptional level. The gene with the highest translational contribution to its induction was CITED-2, which is a negative regulator of HIF-1 transcriptional activity. CONCLUSIONS Gene-specific regulation of mRNA translation contributes significantly to differential gene expression during hypoxia.
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Affiliation(s)
- Marianne Koritzinsky
- Department of Radiation Oncology (MAASTRO Lab), Research Institute Growth and Development, Maastricht, The Netherlands
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16
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Murphy BJ, Sato BG, Dalton TP, Laderoute KR. The metal-responsive transcription factor-1 contributes to HIF-1 activation during hypoxic stress. Biochem Biophys Res Commun 2005; 337:860-7. [PMID: 16216223 DOI: 10.1016/j.bbrc.2005.09.124] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2005] [Accepted: 09/21/2005] [Indexed: 11/23/2022]
Abstract
Hypoxia-inducible factor-1 (HIF-1), the major transcriptional regulator of the mammalian cellular response to low oxygen (hypoxia), is embedded within a complex network of signaling pathways. We have been investigating the importance of another stress-responsive transcription factor, MTF-1, for the adaptation of cells to hypoxia. This article reports that MTF-1 plays a central role in hypoxic cells by contributing to HIF-1 activity. Loss of MTF-1 in transformed Mtf1 null mouse embryonic fibroblasts (MEFs) results in an attenuation of nuclear HIF-1alpha protein accumulation, HIF-1 transcriptional activity, and expression of an established HIF-1 target gene, glucose transporter-1 (Glut1). Mtf1 null (Mtf1 KO) MEFs also have constitutively higher levels of both glutathione (GSH) and the rate-limiting enzyme involved in GSH synthesis--glutamate cysteine ligase catalytic subunit--than wild type cells. The altered cellular redox state arising from increased GSH may perturb oxygen-sensing mechanisms in hypoxic Mtf1 KO cells and decrease the accumulation of HIF-1alpha protein. Together, these novel findings define a role for MTF-1 in the regulation of HIF-1 activity.
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Affiliation(s)
- Brian J Murphy
- Biosciences Division, SRI International, 333 Ravenswood Avenue, Menlo Park, CA 94025-3493, USA.
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17
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Haddad JJ, Harb HL. Cytokines and the regulation of hypoxia-inducible factor (HIF)-1alpha. Int Immunopharmacol 2005; 5:461-83. [PMID: 15683844 DOI: 10.1016/j.intimp.2004.11.009] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2004] [Revised: 09/27/2004] [Accepted: 11/11/2004] [Indexed: 01/25/2023]
Abstract
Hypoxia-inducible factor (HIF)--an oxygen sensor? The HIF-oxygen sensing association type of dogma is, unequivocally, well anchored. But this is only one face of, at least, a double-sided coin. Current concepts charge HIF of taking sides with a yet not well-founded identity--an immunologic sensor and/or regulator. Or, is it really a sensor, put it more correctly, a key player in sensing mechanisms? The evolving association between HIF and immunity emanates from an established linkage that bonds oxidative stress and inflammation--notably the 'biologic response modifiers', or cytokines. HIF is a redox(y)-sensitive transcription factor, and so are cytokines. Recently, cytokines emerged as major regulators of HIF, under physiologic conditions extending the realm of hypoxia. Alternatively, can HIF, like the so infamous inflammatory transcription factor NF-(kappa)B, prove itself as a key player in the regulation of cytokines and, subsequently, the inflammatory process. The targeting of HIF would be, at least theoretically, of therapeutic value, but does it make sense given its intricate role in hypoxia signaling? It is the theme of HIF being an immunologic sensor that will be explored therein--with special emphasis on the regulatory role of cytokines.
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Affiliation(s)
- John J Haddad
- Department of Biology and Biomedical Sciences [corrected] Faculty of Arts and Sciences, Lebanese International University [corrected] Beirut, Lebanon.
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18
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Zhu X, Smith MA, Perry G, Wang Y, Ross AP, Zhao HW, Lamanna JC, Drew KL. MAPKs are differentially modulated in arctic ground squirrels during hibernation. J Neurosci Res 2005; 80:862-8. [PMID: 15884016 DOI: 10.1002/jnr.20526] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Hibernating animals are very tolerant of trauma to the central nervous system such that dramatic fluctuations in cerebral blood flow occur during hibernation and arousal without apparent damage. Indeed, it was demonstrated that Arctic ground squirrels (AGS) experience acute and severe systemic hypoxia along with the dramatic fluctuation in cerebral blood flow when the animals are aroused from hibernation. While initial hypotheses concerned protective mechanisms in the hibernating state, recent evidence of sustained elevation of HIF1alpha in euthermic AGS from our laboratory suggests that a preparatory program of protective gene expression is chronically expressed in euthermic AGS. In this study we evaluated potential neuroprotective adaptations by examining the alteration of intracellular MAPK pathways that may be modulated by hypoperfusion/reperfusion in AGS during hibernation and arousal. We found that ERK and JNK are activated in both euthermic and aroused AGS compared to the hibernating group which positively correlated with HIF1alpha levels. The activation of ERK and JNK associated with HIF1alpha may play an important role in mediating neuroprotective adaptations that is essential for successful hibernation. Interestingly, p38 is activated in euthermic AGS but not in aroused AGS, which shows strong correlation with iNOS induction. Therefore, the attenuation of p38 activation and iNOS induction in hibernating and aroused animals may contribute to the attenuation of inflammation that plays important neuroprotective roles during hibernation. Taken together, the differential modulation of the MAPK pathways may be critical for neuroprotection of AGS necessary for fluctuations in oxygen and nutrient delivery during hibernation.
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Affiliation(s)
- Xiongwei Zhu
- Institute of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA.
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19
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Laderoute KR. The interaction between HIF-1 and AP-1 transcription factors in response to low oxygen. Semin Cell Dev Biol 2005; 16:502-13. [PMID: 16144688 DOI: 10.1016/j.semcdb.2005.03.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Hypoxia-inducible factor-1 (HIF-1) is a critical regulator of the transcriptional response to low oxygen conditions (hypoxia/anoxia) experienced by mammalian cells in both physiological and pathophysiological circumstances. As our understanding of the biology and biochemistry of HIF-1 has grown, it has become apparent that cells adapt to signals generated by low oxygen through a network of stress responsive transcription factors or complexes, which are influenced by HIF-1 activity. This review summarizes our current understanding of the interaction of HIF-1 with AP-1, a classic example of a family of pleiotropic transcription factors that impact on diverse cellular processes and phenotypes, including the adaptation to low oxygen stress. The review focuses on experimental studies involving cultured cells exposed to hypoxia/anoxia, and describes both established and possible interactions between HIF-1 and AP-1 at different levels of cellular organization.
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Affiliation(s)
- Keith R Laderoute
- Biosciences Division, SRI International, Bldg. L, Rm. A258, 333 Ravenswood Avenue, Menlo Park, CA 94025, USA.
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20
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Yun Z, Lin Q, Giaccia AJ. Adaptive myogenesis under hypoxia. Mol Cell Biol 2005; 25:3040-55. [PMID: 15798192 PMCID: PMC1069592 DOI: 10.1128/mcb.25.8.3040-3055.2005] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2004] [Revised: 08/24/2004] [Accepted: 01/18/2005] [Indexed: 01/03/2023] Open
Abstract
Previous studies have indicated that myoblasts can differentiate and repair muscle injury after an ischemic insult. However, it is unclear how hypoxia or glucose deprivation in the ischemic microenvironment affects myoblast differentiation. We have found that myogenesis can adapt to hypoxic conditions. This adaptive mechanism is accompanied by initial inhibition of the myoD, E2A, and myogenin genes followed by resumption of their expression in an oxygen-dependent manner. The regulation of myoD transcription by hypoxia is correlated with transient deacetylation of histones associated with the myoD promoter. It is noteworthy that, unlike the differentiation of other cell types such as preadipocytes or chondroblasts, the effect of hypoxia on myogenesis is independent of HIF-1, a ubiquitous regulator of transcription under hypoxia. While myogenesis can also adapt to glucose deprivation, the combination of severe hypoxia and glucose deprivation found in an ischemic environment results in pronounced loss of myoblasts. Our studies indicate that the ischemic muscle can be repaired via the adaptive differentiation of myogenic precursors, which depends on the levels of oxygen and glucose in the ischemic microenvironment.
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MESH Headings
- Acetylation
- Adaptation, Physiological
- Animals
- Basic Helix-Loop-Helix Transcription Factors
- Cell Differentiation
- Cell Hypoxia
- Cell Line
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- DNA-Binding Proteins/physiology
- Down-Regulation
- Energy Metabolism/genetics
- Energy Metabolism/physiology
- Gene Expression Regulation, Developmental
- Glucose/metabolism
- Histones/metabolism
- Hypoxia-Inducible Factor 1
- Hypoxia-Inducible Factor 1, alpha Subunit
- Mice
- Muscle Development/genetics
- Muscle Development/physiology
- MyoD Protein/genetics
- MyoD Protein/metabolism
- Myoblasts/metabolism
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Myogenin/genetics
- Myogenin/metabolism
- Nuclear Proteins/genetics
- Nuclear Proteins/physiology
- Oxygen/metabolism
- Oxygen/pharmacology
- Promoter Regions, Genetic/drug effects
- Promoter Regions, Genetic/genetics
- RNA Stability
- RNA, Messenger/analysis
- RNA, Messenger/metabolism
- Sequence Deletion
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Transcription Factors/physiology
- Transcription, Genetic
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Affiliation(s)
- Zhong Yun
- Department of Radiation Oncology, Stanford University School of Medicine, 269 Campus Dr., CCSR-1250, Stanford, CA 94305, USA.
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21
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Abstract
Activation of an innate immune response is among the first lines of defense after tissue injury. Restoring blood flow to the site of injured tissue is often a necessary prerequisite for mounting an initial immune response to pathogens and for subsequent initiation of a successful repair of wounded tissue. The multiple links among pathogen recognition and suppression, increased angiogenesis, and tissue repair are the topics of this review, which examines of the roles of antimicrobial peptides, mammalian toll-like receptors (TLRs), inflammatory cytokines, and putative "danger" signals, among other signaling pathways, in triggering, sustaining, and then terminating an angiogenic response.
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Affiliation(s)
- Stefan Frantz
- Genzyme Corporation, Cambridge, Mass 01701-9322, USA
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22
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Comerford KM, Cummins EP, Taylor CT. c-Jun NH2-Terminal Kinase Activation Contributes to Hypoxia-Inducible Factor 1α–Dependent P-Glycoprotein Expression in Hypoxia. Cancer Res 2004; 64:9057-61. [PMID: 15604272 DOI: 10.1158/0008-5472.can-04-1919] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We previously have shown that hypoxia increases the expression of P-glycoprotein, which in turn increases tumor cell capacity to actively extrude chemotherapeutic agents and may contribute to tumor drug resistance. This event is mediated through the hypoxia-inducible factor (HIF-1). Here, we investigated the role of the stress-activated protein kinase c-Jun NH(2)-terminal kinase (JNK) in the signaling mechanisms underlying these events. Hypoxia activates JNK activity in vitro and in vivo. Overexpression of mitogen-activated protein kinase (MAPK) kinase kinase (MEKK-1), which preferentially activates JNK, mimics, in a nonadditive way, hypoxia-induced activity of the MDR1 promoter and expression of MDR1 mRNA and P-glycoprotein. Furthermore, the JNK inhibitor SP600125 selectively and specifically inhibits hypoxia- and MEKK-1-induced MDR1 promoter activity in a dose-dependent manner. JNK inhibition also reversed hypoxia- and MEKK-1-induced activity of an HIF-1-dependent reporter gene. MEKK-1-induced MDR1 expression depends on a functional HIF-1 binding site (hypoxia-responsive element). Hypoxia- but not cobalt chloride-dependent HIF-1-DNA binding and transcriptional activation was inhibited by SP600125, indicating that hypoxia-induced signaling to HIF-1 depends on JNK activation. Because it has been reported that reactive oxygen species are increased in hypoxia and related to JNK activation, we investigated their role in signaling this response. Whereas exogenous addition of H(2)O(2) was sufficient to activate JNK, reactive oxygen species scavengers were without effect on hypoxia-induced JNK or HIF-1 activation. Thus, hypoxia-elicited MDR1 expression, which depends on HIF-1 activation, depends at least in part on signaling via activation of JNK. Furthermore, these events are independent of the generation of reactive oxygen intermediates. Thus, JNK may represent a therapeutic target in the prevention of tumor resistance to chemotherapeutic treatment.
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Affiliation(s)
- Katrina M Comerford
- Department of Medicine and Therapeutics, The Conway Institute for Biomolecular and Biomedical Research and the Dublin Molecular Medicine Centre, University College, Dublin, Ireland
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