1
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Ahmadi M, Morshedzadeh F, Ghaderian SMH, Mousavi P, Habibipour L, Peymani M, Abbaszadegan MR, Ghafouri-Fard S. Carcinogenic roles of MAFG-AS1 in human cancers. Clin Transl Oncol 2024; 26:52-68. [PMID: 37351806 DOI: 10.1007/s12094-023-03246-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Accepted: 06/02/2023] [Indexed: 06/24/2023]
Abstract
The MAF bZIP transcription factor G-antisense RNA 1 (MAFG-AS1) is located on chromosome 17. MAFG-AS1 was upregulated in 15 human cancers. MAFG-AS1 not only suppresses 16 miRNAs but also directly impacts 22 protein-coding genes' expression. Notably, abnormal MAFG-AS1 expression is connected to clinicopathological characteristics and a worse prognosis in a variety of cancers. Moreover, MAFG-AS1 takes its part in the tumorigenesis and progression of various human malignancies by suppressing apoptosis and promoting proliferation, migration, invasion, aerobic glycolysis, ferroptosis, angiogenesis, EMT, and metastasis. Besides, it can predict treatment effectiveness in ER + breast cancer, urothelial bladder carcinoma, and liver cancer by functioning as a trigger of resistance to tamoxifen, sorafenib, and cisplatin. This study systematically presents the functions of MAFG-AS1 in various cancers, as well as the findings of bioinformatics analyses of the MAFG-AS1, which should give clear advice for future research.
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Affiliation(s)
- Mohsen Ahmadi
- Department of Medical Genetics, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Firouzeh Morshedzadeh
- Department of Genetics, Faculty of Basic Sciences, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran
- Department of Medical Genetics and Molecular Medicine, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | - Pegah Mousavi
- Molecular Medicine Research Center, Hormozgan Health Institute, Hormozgan University of Medical Sciences, Bandar Abbas, Iran.
| | - Leila Habibipour
- Department of Biotechnology, Institute of Science and High Technology and Environmental Science, Graduate University of Advanced Technology, Kerman, Iran
| | - Maryam Peymani
- Department of Genetics, Faculty of Basic Sciences, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran
| | - Mohammad Reza Abbaszadegan
- Department of Medical Genetics and Molecular Medicine, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
- Medical Genetics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Soudeh Ghafouri-Fard
- Department of Medical Genetics, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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2
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Li P, Ma X, Gu X. LncRNA MAFG-AS1 is involved in human cancer progression. Eur J Med Res 2023; 28:497. [PMID: 37941063 PMCID: PMC10631199 DOI: 10.1186/s40001-023-01486-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 10/30/2023] [Indexed: 11/10/2023] Open
Abstract
Long noncoding RNAs (lncRNAs) refer to a type of non-protein-coding transcript of more than 200 nucleotides. LncRNAs play fundamental roles in disease development and progression, and lncRNAs are dysregulated in many pathophysiological processes. Thus, lncRNAs may have potential value in clinical applications. The lncRNA, MAF BZIP Transcription Factor G (MAFG)-AS1, is dysregulated in several cancer, including breast cancer, lung cancer, liver cancer, bladder cancer, colorectal cancer, gastric cancer, esophagus cancer, prostate cancer, pancreatic cancer, ovarian cancer, and glioma. Altered MAFG-AS1 levels are also associated with diverse clinical characteristics and patient outcomes. Mechanistically, MAFG-AS1 mediates a variety of cellular processes via the regulation of target gene expression. Therefore, the diagnostic, prognostic, and therapeutic aspects of MAFG-AS1 have been widely explored. In this review, we discuss the expression, major roles, and molecular mechanisms of MAFG-AS1, the relationship between MAFG-AS1 and clinical features of diseases, and the clinical applications of MAFG-AS1.
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Affiliation(s)
- Penghui Li
- Department of Oncology, The First Affiliated Hospital, College of Clinical Medicine, Henan University of Science and Technology, Luoyang, 471000, Henan, China
| | - Xiao Ma
- Zhejiang University School of Medicine, Hangzhou, 310000, Zhejiang, China
| | - Xinyu Gu
- Department of Oncology, The First Affiliated Hospital, College of Clinical Medicine, Henan University of Science and Technology, Luoyang, 471000, Henan, China.
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3
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Modi R, McKee N, Zhang N, Alwali A, Nelson S, Lohar A, Ostafe R, Zhang DD, Parkinson EI. Stapled Peptides as Direct Inhibitors of Nrf2-sMAF Transcription Factors. J Med Chem 2023; 66:6184-6192. [PMID: 37097833 PMCID: PMC10184664 DOI: 10.1021/acs.jmedchem.2c02037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Indexed: 04/26/2023]
Abstract
Nuclear factor erythroid-related 2-factor 2 (Nrf2) is a transcription factor traditionally thought of as a cellular protector. However, in many cancers, Nrf2 is constitutively activated and correlated with therapeutic resistance. Nrf2 heterodimerizes with small musculoaponeurotic fibrosarcoma Maf (sMAF) transcription factors, allowing binding to the antioxidant responsive element (ARE) and induction of transcription of Nrf2 target genes. While transcription factors are historically challenging to target, stapled peptides have shown great promise for inhibiting these protein-protein interactions. Herein, we describe the first direct cell-permeable inhibitor of Nrf2/sMAF heterodimerization. N1S is a stapled peptide designed based on AlphaFold predictions of the interactions between Nrf2 and sMAF MafG. A cell-based reporter assay combined with in vitro biophysical assays demonstrates that N1S directly inhibits Nrf2/MafG heterodimerization. N1S treatment decreases the transcription of Nrf2-dependent genes and sensitizes Nrf2-dependent cancer cells to cisplatin. Overall, N1S is a promising lead for the sensitization of Nrf2-addicted cancers.
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Affiliation(s)
- Ramya Modi
- Department
of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Nick McKee
- Department
of Pharmacology and Toxicology, University
of Arizona, Tucson, Arizona 85721, United States
| | - Ning Zhang
- Department
of Pharmacology and Toxicology, University
of Arizona, Tucson, Arizona 85721, United States
| | - Amir Alwali
- Department
of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Samantha Nelson
- Department
of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907, United States
| | - Aditi Lohar
- Department
of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Raluca Ostafe
- Molecular
Evolution Protein Engineering and Production, Purdue University, West Lafayette, Indiana 47907, United States
| | - Donna D. Zhang
- Department
of Pharmacology and Toxicology, University
of Arizona, Tucson, Arizona 85721, United States
| | - Elizabeth I. Parkinson
- Department
of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
- Department
of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907, United States
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4
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Fu Y, Wen J, Li X, Gong M, Guo Z, Wang G. LncRNA MAFG-AS1 Upregulates Polo-Like Kinase-1 by Sponging miR-505 to Promote Gastric Adenocarcinoma Cell Proliferation. Crit Rev Eukaryot Gene Expr 2021; 31:27-32. [PMID: 34591387 DOI: 10.1615/critreveukaryotgeneexpr.2021038813] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Gastric cancer is a commonly diagnosed, often fatal malignancy and requires novel anticancer therapies and preventative approaches. This study described the involvement of MAFG-AS1, a lncRNA with important functions in cancer biology, in gastric adenocarcinoma (GA). Thirty-six male and forty-two female GA patients with an average age of 51.9 ± 5.7 years in the range of 35 to 68 years were enrolled. Paired gastric cancer (GC) and non-tumor tissues were collected from each patient. MAFG-AS1 expression was determined. RNA interaction prediction, dual luciferase reporter assay, RT-qPCR assay, Western blot, and CCK-8 assay were conducted. The results indicated that MAFG-AS1 was highly expressed in GA and closely correlated with poor survival. MAFG-AS1 interacted with miR-505, but MAFG-AS1 and miR-505 overexpression showed no significant effects on each other's expression. In addition, MAFG-AS1 increased the expression of PLK1, a miR-505 target. MAFG-AS1 and PLK1 overexpression increased GC cell proliferation rate. MiR-505 overexpression reduced the effects of MAFG-AS1 and PLK1 overexpression on cell proliferation. Therefore, MAFG-AS1 might upregulate PLK1 by sponging miR-505 to promote GA cell proliferation.
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Affiliation(s)
- Yunhui Fu
- Department of Gastroenterology, Pingxiang People's Hospital, Pingxiang City, Jiangxi Province, 337000, China
| | - Jianbo Wen
- Department of Gastroenterology, Pingxiang People's Hospital, Pingxiang City, Jiangxi Province, 337000, China
| | - Xing Li
- Department of Gastroenterology, Pingxiang People's Hospital, Pingxiang City, Jiangxi Province, 337000, China
| | - Ming Gong
- Department of Gastroenterology, Pingxiang People's Hospital, Pingxiang City, Jiangxi Province, 337000, China
| | - Zhaoyang Guo
- Department of Gastrointestinal Surgery, Pingxiang People's Hospital, Pingxiang City, Jiangxi Province, 337000, China
| | - Guiliang Wang
- Department of Gastroenterology, Pingxiang People's Hospital, Pingxiang City, Jiangxi Province, 337000, China
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5
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Kapetanaki MG, Gbotosho OT, Sharma D, Weidert F, Ofori-Acquah SF, Kato GJ. Free heme regulates placenta growth factor through NRF2-antioxidant response signaling. Free Radic Biol Med 2019; 143:300-308. [PMID: 31408727 PMCID: PMC6848791 DOI: 10.1016/j.freeradbiomed.2019.08.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 08/01/2019] [Accepted: 08/07/2019] [Indexed: 12/17/2022]
Abstract
Free heme activates erythroblasts to express and secrete Placenta Growth Factor (PlGF), an angiogenic peptide of the VEGF family. High circulating levels of PlGF have been associated in experimental animals and in patients with sickle cell disease with echocardiographic markers of pulmonary hypertension, a life-limiting complication associated with more intense hemolysis. We now show that the mechanism of heme regulation of PlGF requires the contribution of the key antioxidant response regulator NRF2. Mimicking the effect of heme, the NRF2 agonist sulforaphane stimulates the PlGF transcript level nearly 30-fold in cultured human erythroblastoid cells. Heme and sulforaphane also induce transcripts for NRF2 itself, its partners MAFF and MAFG, and its competitor BACH1. Furthermore, heme induction of the PlGF transcript is significantly diminished by the NRF2 inhibitor brusatol and by siRNA knockdown of the NRF2 and/or MAFG transcription factors. Chromatin immunoprecipitation experiments show that heme induces NRF2 to bind directly to the PlGF promoter region. In complementary in vivo experiments, mice injected with heme show a significant increase in their plasma PlGF protein as early as 3 h after treatment. Our results reveal an important mechanism of PlGF regulation, adding to the growing literature that supports the pivotal importance of the NRF2 axis in the pathobiology of sickle cell disease.
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Affiliation(s)
- Maria G Kapetanaki
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Pittsburgh Heart, Lung, Blood, and Vascular Medicine Institute, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Oluwabukola T Gbotosho
- Division of Hematology-Oncology, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Pittsburgh Heart, Lung, Blood, and Vascular Medicine Institute, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Deva Sharma
- Division of Hematology-Oncology, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Pittsburgh Heart, Lung, Blood, and Vascular Medicine Institute, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Frances Weidert
- Pittsburgh Heart, Lung, Blood, and Vascular Medicine Institute, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Solomon F Ofori-Acquah
- Division of Hematology-Oncology, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Pittsburgh Heart, Lung, Blood, and Vascular Medicine Institute, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Center for Translational and International Hematology, Department of Medicine, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Gregory J Kato
- Division of Hematology-Oncology, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Pittsburgh Heart, Lung, Blood, and Vascular Medicine Institute, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
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6
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Yang H, Liu T, Wang J, Li TW, Fan W, Peng H, Krishnan A, Gores GJ, Mato JM, Lu SC. Deregulated methionine adenosyltransferase α1, c-Myc, and Maf proteins together promote cholangiocarcinoma growth in mice and humans(‡). Hepatology 2016; 64:439-55. [PMID: 26969892 PMCID: PMC4956551 DOI: 10.1002/hep.28541] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 02/24/2016] [Accepted: 03/02/2016] [Indexed: 12/11/2022]
Abstract
UNLABELLED c-Myc induction drives cholestatic liver injury and cholangiocarcinoma (CCA) in mice, and induction of Maf proteins (MafG and c-Maf) contributes to cholestatic liver injury, whereas S-adenosylmethionine (SAMe) administration is protective. Here, we determined whether there is interplay between c-Myc, Maf proteins, and methionine adenosyltransferase α1 (MATα1), which is responsible for SAMe biosynthesis in the liver. We used bile duct ligation (BDL) and lithocholic acid (LCA) treatment in mice as chronic cholestasis models, a murine CCA model, human CCA cell lines KMCH and Huh-28, human liver cancer HepG2, and human CCA specimens to study gene and protein expression, protein-protein interactions, molecular mechanisms, and functional outcomes. We found that c-Myc, MATα1 (encoded by MAT1A), MafG, and c-Maf interact with one another directly. MAT1A expression fell in hepatocytes and bile duct epithelial cells during chronic cholestasis and in murine and human CCA. The opposite occurred with c-Myc, MafG, and c-Maf expression. MATα1 interacts mainly with Mnt in normal liver, but this switches to c-Maf, MafG, and c-Myc in cholestatic livers and CCA. Promoter regions of these genes have E-boxes that are bound by MATα1 and Mnt in normal liver and benign bile duct epithelial cells that switched to c-Myc, c-Maf, and MafG in cholestasis and CCA cells. E-box positively regulates c-Myc, MafG, and c-Maf, but it negatively regulates MAT1A. MATα1 represses, whereas c-Myc, MafG, and c-Maf enhance, E-box-driven promoter activity. Knocking down MAT1A or overexpressing MafG or c-Maf enhanced CCA growth and invasion in vivo. CONCLUSION There is a novel interplay between MATα1, c-Myc, and Maf proteins, and their deregulation during chronic cholestasis may facilitate CCA oncogenesis. (Hepatology 2016;64:439-455).
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Affiliation(s)
- Heping Yang
- Division of Gastroenterology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- USC Research Center for Liver Diseases, Keck School of Medicine USC, Los Angeles, CA 90033, USA
| | - Ting Liu
- Division of Gastroenterology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- USC Research Center for Liver Diseases, Keck School of Medicine USC, Los Angeles, CA 90033, USA
- Department of Gastroenterology, Xiangya Hospital Central South University, Changsha, Hunan 410008, China
| | - Jiaohong Wang
- Division of Gastroenterology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- USC Research Center for Liver Diseases, Keck School of Medicine USC, Los Angeles, CA 90033, USA
| | - Tony W.H. Li
- Division of Gastroenterology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- USC Research Center for Liver Diseases, Keck School of Medicine USC, Los Angeles, CA 90033, USA
| | - Wei Fan
- Division of Gastroenterology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- USC Research Center for Liver Diseases, Keck School of Medicine USC, Los Angeles, CA 90033, USA
- Department of Geriatrics, Guangzhou First People’s Hospital, Guangzhou 510180, China
| | - Hui Peng
- Division of Gastroenterology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- USC Research Center for Liver Diseases, Keck School of Medicine USC, Los Angeles, CA 90033, USA
| | - Anuradha Krishnan
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN
| | - Gregory J. Gores
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN
| | - Jose M. Mato
- CIC bioGUNE, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (Ciberehd), Technology, Park of Bizkaia, 48160 Derio, Bizkaia, Spain
| | - Shelly C. Lu
- Division of Gastroenterology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- USC Research Center for Liver Diseases, Keck School of Medicine USC, Los Angeles, CA 90033, USA
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7
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Otsuki A, Suzuki M, Katsuoka F, Tsuchida K, Suda H, Morita M, Shimizu R, Yamamoto M. Unique cistrome defined as CsMBE is strictly required for Nrf2-sMaf heterodimer function in cytoprotection. Free Radic Biol Med 2016; 91:45-57. [PMID: 26677805 DOI: 10.1016/j.freeradbiomed.2015.12.005] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2015] [Revised: 12/01/2015] [Accepted: 12/06/2015] [Indexed: 12/30/2022]
Abstract
Nrf2-small Maf (sMaf) heterodimer is essential for the inducible expression of cytoprotective genes upon exposure to oxidative and xenobiotic stresses. While the Nrf2-sMaf heterodimer recognizes DNA sequences referred to as the antioxidant/electrophile responsive element (ARE/EpRE), we here define these DNA sequences collectively as CNC-sMaf binding element (CsMBE). In contrast, large and small Maf proteins are able to form homodimers that recognize the Maf recognition element (MARE). CsMBE and MARE share a conserved core sequence but they differ in the 5'-adjacent nucleotide neighboring the core. Because of the high similarity between the CsMBE and MARE sequences, it has been unclear how many target binding sites and target genes are shared by the Nrf2-sMaf heterodimers and Maf homodimers. To address this issue, we introduced a substitution mutation of alanine to tyrosine at position 502 in Nrf2, which rendered the DNA-binding domain structure of Nrf2 similar to Maf, and generated knock-in mice expressing the Nrf2(A502Y) mutant. Our chromatin immunoprecipitation-sequencing analyses showed that binding sites of Nrf2(A502Y)-sMaf were dramatically changed from CsMBE to MARE in vivo. Intriguingly, however, one-quarter of the Nrf2(A502Y)-sMaf binding sites also bound Nrf2-sMaf commonly and vice versa. RNA-sequencing analyses revealed that Nrf2(A502Y)-sMaf failed to induce expression of major cytoprotective genes upon stress stimulation, which increased the sensitivity of Nrf2(A502Y) mutant mice to acute acetaminophen toxicity. These results demonstrate that the unique cistrome defined as CsMBE is strictly required for the Nrf2-sMaf heterodimer function in cytoprotection and that the roles played by CsMBE differ sharply from those of MARE.
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Affiliation(s)
- Akihito Otsuki
- Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Mikiko Suzuki
- Center for Radioisotope Sciences, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan.
| | - Fumiki Katsuoka
- Tohoku Medical Megabank Organization, Tohoku University, Sendai 980-8573, Japan
| | - Kouhei Tsuchida
- Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Hiromi Suda
- Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Masanobu Morita
- Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Ritsuko Shimizu
- Department of Molecular Hematology, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Masayuki Yamamoto
- Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan; Tohoku Medical Megabank Organization, Tohoku University, Sendai 980-8573, Japan.
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8
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Abstract
An MAFG-containing corepressor complex induces CIMP in BRAF(V600E)-positive colorectal cancer.
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9
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Fang M, Ou J, Hutchinson L, Green MR. The BRAF oncoprotein functions through the transcriptional repressor MAFG to mediate the CpG Island Methylator phenotype. Mol Cell 2014; 55:904-915. [PMID: 25219500 PMCID: PMC4170521 DOI: 10.1016/j.molcel.2014.08.010] [Citation(s) in RCA: 157] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 07/14/2014] [Accepted: 08/06/2014] [Indexed: 12/16/2022]
Abstract
Most colorectal cancers (CRCs) containing activated BRAF (BRAF[V600E]) have a CpG island methylator phenotype (CIMP) characterized by aberrant hypermethylation of many genes, including the mismatch repair gene MLH1. MLH1 silencing results in microsatellite instability and a hypermutable phenotype. Through an RNAi screen, here we identify the transcriptional repressor MAFG as the pivotal factor required for MLH1 silencing and CIMP in CRCs containing BRAF(V600E). In BRAF-positive human CRC cell lines and tumors, MAFG is bound at the promoters of MLH1 and other CIMP genes, and recruits a corepressor complex that includes its heterodimeric partner BACH1, the chromatin remodeling factor CHD8, and the DNA methyltransferase DNMT3B, resulting in hypermethylation and transcriptional silencing. BRAF(V600E) increases BRAF/MEK/ERK signaling resulting in phosphorylation and elevated levels of MAFG, which drives DNA binding. Analysis of transcriptionally silenced CIMP genes in KRAS-positive CRCs indicates that different oncoproteins direct the assembly of distinct repressor complexes on common promoters.
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Affiliation(s)
- Minggang Fang
- Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA; Programs in Gene Function and Expression and Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Jianhong Ou
- Programs in Gene Function and Expression and Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Lloyd Hutchinson
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Michael R Green
- Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA; Programs in Gene Function and Expression and Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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10
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Tomasi ML, Ryoo M, Yang H, Iglesias Ara A, Ko KS, Lu SC. Molecular mechanisms of lipopolysaccharide-mediated inhibition of glutathione synthesis in mice. Free Radic Biol Med 2014; 68:148-58. [PMID: 24296246 PMCID: PMC3943979 DOI: 10.1016/j.freeradbiomed.2013.11.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2013] [Accepted: 11/20/2013] [Indexed: 12/12/2022]
Abstract
Endotoxemia correlates with the degree of liver failure and may participate in worsening of liver diseases. Lipopolysaccharide (LPS; synonymous with endotoxin) treatment in mice lowered the hepatic glutathione (GSH) level, which in turn is a variable that determines susceptibility to LPS-induced injury. We previously showed that LPS treatment in mice lowered hepatic expression of the rate-limiting enzyme in GSH synthesis, glutamate-cysteine ligase (GCL). The aim of our current work was to determine the molecular mechanism(s) responsible for these changes. Studies were done using RAW cells (murine macrophages), in vivo LPS-treated mice, and mouse hepatocytes. We found that LPS treatment lowered GCL catalytic and modifier (Gclc and Gclm) subunit expression at the transcriptional level, which was unrelated to alterations in nitric oxide production or induction of NF-κB/p65 subunit. The key mechanism was a decrease in sumoylation of nuclear factor-erythroid 2-related factor 2 (Nrf2) and MafG, which is required for their heterodimerization and subsequent binding and trans-activation of the antioxidant-response element (ARE) present in the promoter region of these genes that is essential for their expression. LPS treatment lowered markedly the expression of ubiquitin-conjugating enzyme 9 (Ubc9), which is required for sumoylation. Similar findings also occurred in liver after in vivo LPS treatment and in LPS-treated mouse hepatocytes. Overexpression of Ubc9 protected against LPS-mediated inhibition of Gclc and Gclm expression in RAW cells and hepatocytes. In conclusion, LPS-mediated lowering of GCL expression in hepatocytes and macrophages is due to lowering of sumoylation of Nrf2 and MafG, leading to reduced heterodimerization, binding, and trans-activation of ARE.
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Affiliation(s)
- Maria Lauda Tomasi
- Division of Gastroenterology and Liver Diseases, USC Research Center for Liver Diseases, Los Angeles, CA 90033, USA; Southern California Research Center for Alcoholic Liver and Pancreatic Diseases and Cirrhosis, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Minjung Ryoo
- Division of Gastroenterology and Liver Diseases, USC Research Center for Liver Diseases, Los Angeles, CA 90033, USA; Southern California Research Center for Alcoholic Liver and Pancreatic Diseases and Cirrhosis, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Heping Yang
- Division of Gastroenterology and Liver Diseases, USC Research Center for Liver Diseases, Los Angeles, CA 90033, USA; Southern California Research Center for Alcoholic Liver and Pancreatic Diseases and Cirrhosis, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Ainhoa Iglesias Ara
- Division of Gastroenterology and Liver Diseases, USC Research Center for Liver Diseases, Los Angeles, CA 90033, USA; Department of Genetics, Faculty of Science and Technology, University of the Basque Country, Leioa, Bilbao, Spain
| | - Kwang Suk Ko
- Division of Gastroenterology and Liver Diseases, USC Research Center for Liver Diseases, Los Angeles, CA 90033, USA; Department of Nutritional Science and Food Management, College of Health Science, Ewha Women's University, Seoul, Korea
| | - Shelly C Lu
- Division of Gastroenterology and Liver Diseases, USC Research Center for Liver Diseases, Los Angeles, CA 90033, USA; Southern California Research Center for Alcoholic Liver and Pancreatic Diseases and Cirrhosis, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.
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Wu T, Wang XJ, Tian W, Jaramillo MC, Lau A, Zhang DD. Poly(ADP-ribose) polymerase-1 modulates Nrf2-dependent transcription. Free Radic Biol Med 2014; 67:69-80. [PMID: 24140708 PMCID: PMC3945083 DOI: 10.1016/j.freeradbiomed.2013.10.806] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 09/29/2013] [Accepted: 10/14/2013] [Indexed: 12/18/2022]
Abstract
The basic leucine zipper transcription factor Nrf2 has emerged as a master regulator of intracellular redox homeostasis by controlling the expression of a battery of redox-balancing antioxidants and phase II detoxification enzymes. Under oxidative stress conditions, Nrf2 is induced at the protein level through redox-sensitive modifications on critical cysteine residues in Keap1, a component of an E3 ubiquitin ligase complex that targets Nrf2 for proteasomal degradation. Poly(ADP-ribose) polymerase-1 (PARP-1) is historically known to function in DNA damage detection and repair; however, recently PARP-1 has been shown to play an important role in other biochemical activities, such as DNA methylation and imprinting, insulator activity, chromosome organization, and transcriptional regulation. The exact role of PARP-1 in transcription modulation and the underlying mechanisms remain poorly defined. In this study, we report that PARP-1 forms complexes with the antioxidant response element (ARE) within the promoter region of Nrf2 target genes and upregulates the transcriptional activity of Nrf2. Interestingly, PARP-1 neither physically interacts with Nrf2 nor promotes the expression of Nrf2. In addition, PARP-1 does not target Nrf2 for poly(ADP-ribosyl)ation. Instead, PARP-1 interacts directly with small Maf proteins and the ARE of Nrf2 target genes, which augments ARE-specific DNA-binding of Nrf2 and enhances the transcription of Nrf2 target genes. Collectively, these results suggest that PARP-1 serves as a transcriptional coactivator, upregulating the transcriptional activity of Nrf2 by enhancing the interaction among Nrf2, MafG, and the ARE.
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Affiliation(s)
- Tongde Wu
- Department of Pharmacology & Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ 85721, USA
| | - Xiao-Jun Wang
- Department of Pharmacology & Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ 85721, USA
| | - Wang Tian
- Department of Pharmacology & Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ 85721, USA
| | - Melba C Jaramillo
- Department of Pharmacology & Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ 85721, USA
| | - Alexandria Lau
- Department of Pharmacology & Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ 85721, USA
| | - Donna D Zhang
- Department of Pharmacology & Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ 85721, USA; Arizona Cancer Center, University of Arizona, Tucson, AZ 85724, USA.
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Kwong EK, Kim KM, Penalosa PJ, Chan JY. Characterization of Nrf1b, a novel isoform of the nuclear factor-erythroid-2 related transcription factor-1 that activates antioxidant response element-regulated genes. PLoS One 2012; 7:e48404. [PMID: 23144760 PMCID: PMC3483171 DOI: 10.1371/journal.pone.0048404] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 10/01/2012] [Indexed: 12/30/2022] Open
Abstract
Nuclear factor E2-related factor 1 (Nrf1) is a basic leucine zipper transcription factor that plays an important role in the activation of cytoprotective genes through the antioxidant response elements. The previously characterized long isoform of Nrf1 (Nrf1a) is targeted to the endoplasmic reticulum and accumulates in the nucleus in response to activating signals. Here we characterized a novel Nrf1 protein isoform (Nrf1b) generated through an alternative promoter and first exon that lacks the ER targeting domain of Nrf1a. The 5′-flanking region of Nrf1b directed high levels of luciferase reporter expression in cells. RT-PCR and Western blotting showed Nrf1b is widely expressed in various cell lines and mouse tissues. Immunoblot analysis of subcellular fractions and imaging of green fluorescence protein (GFP)-tagged Nrf1b demonstrate Nrf1b is constitutively localized to the nucleus. Nrf1b can activate GAL4-dependent transcription when fused to the heterologous GAL4 DNA-binding domain. Gel-shift and coimmunoprecipitation experiments demonstrate that Nrf1b forms a complex with MafG, and expression of Nrf1b activates the expression of antioxidant response element containing reporters and genes in cells. These results suggest Nrf1b is targeted to the nucleus where it activates ARE-driven genes and may play a role in modulating antioxidant response elements.
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Affiliation(s)
- Eric K. Kwong
- Department of Laboratory Medicine and Pathology, University of California Irvine, Irvine, California, United States of America
| | - Kyung-Mi Kim
- Department of Laboratory Medicine and Pathology, University of California Irvine, Irvine, California, United States of America
| | - Patrick J. Penalosa
- Department of Laboratory Medicine and Pathology, University of California Irvine, Irvine, California, United States of America
| | - Jefferson Y. Chan
- Department of Laboratory Medicine and Pathology, University of California Irvine, Irvine, California, United States of America
- * E-mail:
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Hirotsu Y, Katsuoka F, Funayama R, Nagashima T, Nishida Y, Nakayama K, Douglas Engel J, Yamamoto M. Nrf2-MafG heterodimers contribute globally to antioxidant and metabolic networks. Nucleic Acids Res 2012; 40:10228-39. [PMID: 22965115 PMCID: PMC3488259 DOI: 10.1093/nar/gks827] [Citation(s) in RCA: 295] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
NF-E2-related factor 2 (Nrf2) is a key transcription factor that is critical for cellular defense against oxidative and xenobiotic insults. Nrf2 heterodimerizes with small Maf (sMaf) proteins and binds to antioxidant response elements (AREs) to activate a battery of cytoprotective genes. However, it remains unclear to what extent the Nrf2–sMaf heterodimers contribute to ARE-dependent gene regulation on a genome-wide scale. We performed chromatin immunoprecipitation coupled with high-throughput sequencing and identified the binding sites of Nrf2 and MafG throughout the genome. Compared to sites occupied by Nrf2 alone, many sites co-occupied by Nrf2 and MafG exhibit high enrichment and are located in species-conserved genomic regions. The ARE motifs were significantly enriched among the recovered Nrf2–MafG-binding sites but not among the Nrf2-binding sites that did not display MafG binding. The majority of the Nrf2-regulated cytoprotective genes were found in the vicinity of Nrf2–MafG-binding sites. Additionally, sequences that regulate glucose metabolism and several amino acid transporters were identified as Nrf2–MafG target genes, suggesting diverse roles for the Nrf2–MafG heterodimer in stress response. These data clearly support the notion that Nrf2–sMaf heterodimers are complexes that regulate batteries of genes involved in various aspects of cytoprotective and metabolic functions through associated AREs.
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Affiliation(s)
- Yosuke Hirotsu
- Department of Medical Biochemistry, Department of Integrative Genomics, Tohoku Medical Megabank Organization, Division of Cell Proliferation, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan and Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109-220, USA
| | - Fumiki Katsuoka
- Department of Medical Biochemistry, Department of Integrative Genomics, Tohoku Medical Megabank Organization, Division of Cell Proliferation, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan and Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109-220, USA
- *To whom correspondence should be addressed. Tel: +81 22 717 8084; Fax: +81 22 717 8090;
| | - Ryo Funayama
- Department of Medical Biochemistry, Department of Integrative Genomics, Tohoku Medical Megabank Organization, Division of Cell Proliferation, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan and Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109-220, USA
| | - Takeshi Nagashima
- Department of Medical Biochemistry, Department of Integrative Genomics, Tohoku Medical Megabank Organization, Division of Cell Proliferation, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan and Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109-220, USA
| | - Yuichiro Nishida
- Department of Medical Biochemistry, Department of Integrative Genomics, Tohoku Medical Megabank Organization, Division of Cell Proliferation, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan and Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109-220, USA
| | - Keiko Nakayama
- Department of Medical Biochemistry, Department of Integrative Genomics, Tohoku Medical Megabank Organization, Division of Cell Proliferation, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan and Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109-220, USA
| | - James Douglas Engel
- Department of Medical Biochemistry, Department of Integrative Genomics, Tohoku Medical Megabank Organization, Division of Cell Proliferation, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan and Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109-220, USA
| | - Masayuki Yamamoto
- Department of Medical Biochemistry, Department of Integrative Genomics, Tohoku Medical Megabank Organization, Division of Cell Proliferation, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan and Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109-220, USA
- Correspondence may also be addressed to Fumiki Katsuoka. Tel: +81 22 717 8089; Fax: +81 22 717 8090;
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Yamamoto T, Kyo M, Kamiya T, Tanaka T, Engel JD, Motohashi H, Yamamoto M. Predictive base substitution rules that determine the binding and transcriptional specificity of Maf recognition elements. Genes Cells 2006; 11:575-91. [PMID: 16716189 DOI: 10.1111/j.1365-2443.2006.00965.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Small Maf transcription factors possess a basic region-leucine zipper motif through which they form homodimers or heterodimers with CNC and Bach proteins. Different combinations of small Maf and CNC/Bach protein dimers bind to cis-acting DNA elements, collectively referred to as Maf-recognition elements (MAREs), to either activate or repress transcription. As MAREs defined by function are often divergent from the consensus sequence, we speculated that sequence variations in the MAREs form the basis for selective Maf:Maf or Maf:CNC dimer binding. To test this hypothesis, we analyzed the binding of Maf-containing dimers to variant sequences of the MARE using bacterially expressed MafG and Nrf2 proteins and a surface plasmon resonance-microarray imaging technique. We found that base substitutions in the MAREs actually determined their binding preference for different dimers. In fact, we were able to categorize MAREs into five groups: MafG homodimer-orientd MAREs (Groups I and II), ambivalent MAREs (Group III), MafG:Nrf2 heterodimer-orientd MAREs (Group IV), and silent MAREs (Group V). This study thus manifests that a clear set of rules pertaining to the cis-acting element determine whether a given MARE preferentially associates with MafG homodimer or with MafG:Nrf2 heterodimer.
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Affiliation(s)
- Tae Yamamoto
- Graduate School of Comprehensive Human Sciences and Center for Tsukuba Advanced Research Alliance, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8577, Japan
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Motohashi H, Katsuoka F, Miyoshi C, Uchimura Y, Saitoh H, Francastel C, Engel JD, Yamamoto M. MafG sumoylation is required for active transcriptional repression. Mol Cell Biol 2006; 26:4652-63. [PMID: 16738329 PMCID: PMC1489127 DOI: 10.1128/mcb.02193-05] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A straightforward mechanism for eliciting transcriptional repression would be to simply block the DNA binding site for activators. Such passive repression is often mediated by transcription factors that lack an intrinsic repressor activity. MafG is a bidirectional regulator of transcription, a repressor in its homodimeric state but an activator when heterodimerized with p45. Here, we report that MafG is conjugated to SUMO-2/3 in vivo. To clarify the possible physiological role(s) for sumoylation in regulating MafG activity, we evaluated mutant and wild-type MafG in transgenic mice and cultured cells. Whereas sumoylation-deficient MafG activated p45-dependent transcription normally and did not affect heterodimer activity, repression by the sumoylation-deficient MafG mutant was severely compromised in vivo. Furthermore, the SUMO-dependent repression activity of MafG was sensitive to histone deacetylase inhibition. Thus, repression by MafG is not achieved through simple passive repression by competing for the activator binding site but requires sumoylation, which then mediates transcriptional repression through recruitment of a repressor complex containing histone deacetylase activity.
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Affiliation(s)
- Hozumi Motohashi
- Graduate School of Comprehensive Human Sciences and Center for Tsukuba Advanced Research Alliance, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8577, Japan.
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