1
|
Xiong Y, Luo J, Hong ZY, Zhu WZ, Hu A, Song BL. Hyperactivation of SREBP induces pannexin-1-dependent lytic cell death. J Lipid Res 2024; 65:100579. [PMID: 38880128 DOI: 10.1016/j.jlr.2024.100579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 06/06/2024] [Accepted: 06/09/2024] [Indexed: 06/18/2024] Open
Abstract
Sterol-regulatory element binding proteins (SREBPs) are a conserved transcription factor family governing lipid metabolism. When cellular cholesterol level is low, SREBP2 is transported from the endoplasmic reticulum to the Golgi apparatus where it undergoes proteolytic activation to generate a soluble N-terminal fragment, which drives the expression of lipid biosynthetic genes. Malfunctional SREBP activation is associated with various metabolic abnormalities. In this study, we find that overexpression of the active nuclear form SREBP2 (nSREBP2) causes caspase-dependent lytic cell death in various types of cells. These cells display typical pyroptotic and necrotic signatures, including plasma membrane ballooning and release of cellular contents. However, this phenotype is independent of the gasdermin family proteins or mixed lineage kinase domain-like (MLKL). Transcriptomic analysis identifies that nSREBP2 induces expression of p73, which further activates caspases. Through whole-genome CRISPR-Cas9 screening, we find that Pannexin-1 (PANX1) acts downstream of caspases to promote membrane rupture. Caspase-3 or 7 cleaves PANX1 at the C-terminal tail and increases permeability. Inhibition of the pore-forming activity of PANX1 alleviates lytic cell death. PANX1 can mediate gasdermins and MLKL-independent cell lysis during TNF-induced or chemotherapeutic reagents (doxorubicin or cisplatin)-induced cell death. Together, this study uncovers a noncanonical function of SREBPs as a potentiator of programmed cell death and suggests that PANX1 can directly promote lytic cell death independent of gasdermins and MLKL.
Collapse
Affiliation(s)
- Yanni Xiong
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Taikang Center for Life and Medical Sciences, Taikang Medical School, Wuhan University, Wuhan, China
| | - Jie Luo
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Taikang Center for Life and Medical Sciences, Taikang Medical School, Wuhan University, Wuhan, China
| | - Zi-Yun Hong
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Taikang Center for Life and Medical Sciences, Taikang Medical School, Wuhan University, Wuhan, China
| | - Wen-Zhuo Zhu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Taikang Center for Life and Medical Sciences, Taikang Medical School, Wuhan University, Wuhan, China
| | - Ao Hu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Taikang Center for Life and Medical Sciences, Taikang Medical School, Wuhan University, Wuhan, China
| | - Bao-Liang Song
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Taikang Center for Life and Medical Sciences, Taikang Medical School, Wuhan University, Wuhan, China.
| |
Collapse
|
2
|
Li K, Huang Z, Liu C, Xu Y, Chen W, Shi L, Li C, Zhou F, Zhou F. Transcriptomic analysis of human pulmonary microvascular endothelial cells treated with LPS. Cell Signal 2023; 111:110870. [PMID: 37633475 DOI: 10.1016/j.cellsig.2023.110870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 08/08/2023] [Accepted: 08/23/2023] [Indexed: 08/28/2023]
Abstract
Acute respiratory distress syndrome (ARDS) has a rapid onset and progression, which lead to the severity and complexity of the primary disease and significantly increase the fatality rate of patients. Transcriptomics provides some ideas for clarifying the mechanism of ARDS, exploring prevention and treatment targets, and searching for related specific markers. In this study, RNA-Seq technology was used to observe the gene expression of human pulmonary microvascular endothelial cells (PMVECs) induced by LPS, and to excavate the key genes and signaling pathways in ARDS process. A total of 2300 up-regulated genes were detected, and a corresponding 1696 down-regulated genes were screened. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, and protein-protein interaction (PPI) were also used for functional annotation of key genes. TFDP1 was identified as a cell cycle-dependent differentially expressed gene, and its reduced expression was verified in LPS-treated PMVECs and lung tissues of CLP-induced mice. In addition, the inhibition of TFDP1 on inflammation and apoptosis, and the promotion of proliferation were confirmed. The decreased expression of E2F1, Rb, CDK1 and the activation of MAPK signaling pathway were substantiated in the in vivo and in vitro models of ARDS. Moreover, SREBF1 has been demonstrated to be involved in cell cycle arrest in PMVECs by inhibiting CDK1. Our study shows that transcriptomics combined with basic research can broaden the investigation of ARDS mechanisms and may provide a basis for future mechanistic innovations.
Collapse
Affiliation(s)
- Kaili Li
- Department of Emergency, The First Affiliated Hospital of Chongqing Medical University, 400016 Chongqing, China.
| | - Zuotian Huang
- Department of Hepatobiliary Pancreatic Tumor Center, Chongqing University Cancer Hospital, 400030 Chongqing Municipality, China
| | - Chang Liu
- Department of Critical Care Medicine, the First Affiliated Hospital of Chongqing Medical University, 400016 Chongqing, China.
| | - Yuanyuan Xu
- Department of Critical Care Medicine, the First Affiliated Hospital of Chongqing Medical University, 400016 Chongqing, China
| | - Wei Chen
- Department of Critical Care Medicine, the First Affiliated Hospital of Chongqing Medical University, 400016 Chongqing, China
| | - Lu Shi
- Department of Critical Care Medicine, the First Affiliated Hospital of Chongqing Medical University, 400016 Chongqing, China
| | - Can Li
- Department of Critical Care Medicine, the First Affiliated Hospital of Chongqing Medical University, 400016 Chongqing, China
| | - Fawei Zhou
- Department of Critical Care Medicine, the First Affiliated Hospital of Chongqing Medical University, 400016 Chongqing, China
| | - Fachun Zhou
- Department of Emergency, The First Affiliated Hospital of Chongqing Medical University, 400016 Chongqing, China; Department of Critical Care Medicine, the First Affiliated Hospital of Chongqing Medical University, 400016 Chongqing, China.
| |
Collapse
|
3
|
Araki M, Nakagawa Y, Saito H, Yamada Y, Han SI, Mizunoe Y, Ohno H, Miyamoto T, Sekiya M, Matsuzaka T, Sone H, Shimano H. Hepatocyte- or macrophage-specific SREBP-1a deficiency in mice exacerbates methionine- and choline-deficient diet-induced nonalcoholic fatty liver disease. Am J Physiol Gastrointest Liver Physiol 2022; 323:G627-G639. [PMID: 36283088 DOI: 10.1152/ajpgi.00090.2022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Sterol regulatory element-binding proteins (SREBPs) are master transcription factors for lipid synthesis, and SREBP-1 is important for fatty acid and triglyceride synthesis. SREBP-1 has two isoforms, SREBP-1a and SREBP-1c, which are splicing variants transcribed from the Srebf1 gene. Although SREBP-1a exhibits stronger transcriptional activity than SREBP-1c, hepatic SREBP-1c is considered more physiologically important. We generated SREBP-1a flox mice using the CRISPR/Cas9 system and hepatocyte- and macrophage-specific SREBP-1a knockout (KO) mice (LKO, liver-knockout; and mΦKO, macrophage-knockout). There were no significant differences among all the mouse genotypes upon feeding with a normal diet. However, feeding with a methionine- and choline-deficient (MCD) diet resulted in exacerbated liver injury in both KO mice. In LKO mice, fatty liver was unexpectedly exacerbated, leading to macrophage infiltration and inflammation. In contrast, in mΦKO mice, the fatty liver state was similar to that in flox mice, but the polarity of the macrophages in the liver was transformed into a proinflammatory M1 subtype, resulting in the exacerbation of inflammation. Taken together, we found that SREBP-1a does not contribute to hepatic lipogenesis, but in either hepatocytes or macrophages distinctly controls the onset of pathological conditions in MCD diet-induced hepatitis.NEW & NOTEWORTHY Hepatocyte- and macrophage-specific SREBP-1a knockout mice were generated for the first time. This study reveals that SREBP-1a does not contribute to hepatic lipogenesis, but in either hepatocytes or macrophages distinctly controls the onset of pathological conditions in methionine- and choline-deficient diet-induced hepatitis.
Collapse
Affiliation(s)
- Masaya Araki
- Department of Endocrinology and Metabolism, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Yoshimi Nakagawa
- Department of Endocrinology and Metabolism, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.,Division of Complex Biosystem Research, Department of Research and Development, Institute of Natural Medicine, University of Toyama, Toyama, Japan.,Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Japan
| | - Hodaka Saito
- Division of Complex Biosystem Research, Department of Research and Development, Institute of Natural Medicine, University of Toyama, Toyama, Japan
| | - Yasunari Yamada
- Division of Complex Biosystem Research, Department of Research and Development, Institute of Natural Medicine, University of Toyama, Toyama, Japan
| | - Song-Iee Han
- Department of Endocrinology and Metabolism, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.,International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan
| | - Yuhei Mizunoe
- Department of Endocrinology and Metabolism, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Hiroshi Ohno
- Department of Endocrinology and Metabolism, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Takafumi Miyamoto
- Department of Endocrinology and Metabolism, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Motohiro Sekiya
- Department of Endocrinology and Metabolism, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Takashi Matsuzaka
- Department of Endocrinology and Metabolism, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.,Transborder Medical Research Center (TMRC), University of Tsukuba, Tsukuba, Japan
| | - Hirohito Sone
- Department of Hematology, Endocrinology and Metabolism, Faculty of Medicine, Niigata University, Niigata, Japan
| | - Hitoshi Shimano
- Department of Endocrinology and Metabolism, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.,Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Japan.,International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan.,Japan Agency for Medical Research and Development-Core Research for Evolutional Science and Technology (AMED-CREST), Tokyo, Japan
| |
Collapse
|
4
|
Zhao Q, Lin X, Wang G. Targeting SREBP-1-Mediated Lipogenesis as Potential Strategies for Cancer. Front Oncol 2022; 12:952371. [PMID: 35912181 PMCID: PMC9330218 DOI: 10.3389/fonc.2022.952371] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 06/22/2022] [Indexed: 11/13/2022] Open
Abstract
Sterol regulatory element binding protein-1 (SREBP-1), a transcription factor with a basic helix–loop–helix leucine zipper, has two isoforms, SREBP-1a and SREBP-1c, derived from the same gene for regulating the genes of lipogenesis, including acetyl-CoA carboxylase, fatty acid synthase, and stearoyl-CoA desaturase. Importantly, SREBP-1 participates in metabolic reprogramming of various cancers and has been a biomarker for the prognosis or drug efficacy for the patients with cancer. In this review, we first introduced the structure, activation, and key upstream signaling pathway of SREBP-1. Then, the potential targets and molecular mechanisms of SREBP-1-regulated lipogenesis in various types of cancer, such as colorectal, prostate, breast, and hepatocellular cancer, were summarized. We also discussed potential therapies targeting the SREBP-1-regulated pathway by small molecules, natural products, or the extracts of herbs against tumor progression. This review could provide new insights in understanding advanced findings about SREBP-1-mediated lipogenesis in cancer and its potential as a target for cancer therapeutics.
Collapse
Affiliation(s)
- Qiushi Zhao
- National Engineering Laboratory for AIDS Vaccine, Key Laboratory for Molecular Enzymology and Engineering, The Ministry of Education, School of Life Sciences, Jilin University, Changchun, China
| | - Xingyu Lin
- Department of Thoracic Surgery, The First Hospital of Jilin University, Changchun, China
- *Correspondence: Xingyu Lin, ; Guan Wang,
| | - Guan Wang
- National Engineering Laboratory for AIDS Vaccine, Key Laboratory for Molecular Enzymology and Engineering, The Ministry of Education, School of Life Sciences, Jilin University, Changchun, China
- *Correspondence: Xingyu Lin, ; Guan Wang,
| |
Collapse
|
5
|
Kanagasabai T, Li G, Shen TH, Gladoun N, Castillo-Martin M, Celada SI, Xie Y, Brown LK, Mark ZA, Ochieng J, Ballard BR, Cordon-Cardo C, Adunyah SE, Jin R, Matusik RJ, Chen Z. MicroRNA-21 deficiency suppresses prostate cancer progression through downregulation of the IRS1-SREBP-1 signaling pathway. Cancer Lett 2022; 525:46-54. [PMID: 34610416 DOI: 10.1016/j.canlet.2021.09.041] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/21/2021] [Accepted: 09/29/2021] [Indexed: 12/24/2022]
Abstract
Sterol regulatory element-binding protein 1 (SREBP-1), a master transcription factor in lipogenesis and lipid metabolism, is critical for disease progression and associated with poor outcomes in prostate cancer (PCa) patients. However, the mechanism of SREBP-1 regulation in PCa remains elusive. Here, we report that SREBP-1 is transcriptionally regulated by microRNA-21 (miR-21) in vitro in cultured cells and in vivo in mouse models. We observed aberrant upregulation of SREBP-1, fatty acid synthase (FASN) and acetyl-CoA carboxylase (ACC) in Pten/Trp53 double-null mouse embryonic fibroblasts (MEFs) and Pten/Trp53 double-null mutant mice. Strikingly, miR-21 loss significantly reduced cell proliferation and suppressed the prostate tumorigenesis of Pten/Trp53 mutant mice. Mechanistically, miR-21 inactivation decreased the levels of SREBP-1, FASN, and ACC in human PCa cells through downregulation of insulin receptor substrate 1 (IRS1)-mediated transcription and induction of cellular senescence. Conversely, miR-21 overexpression increased cell proliferation and migration; as well as the levels of IRS1, SREBP-1, FASN, and ACC in human PCa cells. Our findings reveal that miR-21 promotes PCa progression by activating the IRS1/SREBP-1 axis, and targeting miR-21/SREBP-1 signaling pathway can be a novel strategy for controlling PCa malignancy.
Collapse
Affiliation(s)
- Thanigaivelan Kanagasabai
- Department of Biochemistry, Cancer Biology, Neuroscience and Pharmacology, Meharry Medical College, Nashville, TN, 37208, USA
| | - Guoliang Li
- Department of Biochemistry, Cancer Biology, Neuroscience and Pharmacology, Meharry Medical College, Nashville, TN, 37208, USA
| | - Tian Huai Shen
- Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY, 10032, USA
| | - Nataliya Gladoun
- Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY, 10032, USA
| | - Mireia Castillo-Martin
- Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY, 10032, USA
| | - Sherly I Celada
- Department of Biological Sciences, Tennessee State University, Nashville, TN, 37209, USA
| | - Yingqiu Xie
- Department of Biochemistry, Cancer Biology, Neuroscience and Pharmacology, Meharry Medical College, Nashville, TN, 37208, USA
| | - Lakendria K Brown
- Department of Biochemistry, Cancer Biology, Neuroscience and Pharmacology, Meharry Medical College, Nashville, TN, 37208, USA
| | - Zaniya A Mark
- Department of Biochemistry, Cancer Biology, Neuroscience and Pharmacology, Meharry Medical College, Nashville, TN, 37208, USA
| | - Josiah Ochieng
- Department of Biochemistry, Cancer Biology, Neuroscience and Pharmacology, Meharry Medical College, Nashville, TN, 37208, USA
| | - Billy R Ballard
- Department of Pathology, Anatomy and Cell Biology, Meharry Medical College, Nashville, TN, 37208, USA
| | - Carlos Cordon-Cardo
- Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY, 10032, USA
| | - Samuel E Adunyah
- Department of Biochemistry, Cancer Biology, Neuroscience and Pharmacology, Meharry Medical College, Nashville, TN, 37208, USA
| | - Renjie Jin
- Department of Urology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Robert J Matusik
- Department of Urology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Zhenbang Chen
- Department of Biochemistry, Cancer Biology, Neuroscience and Pharmacology, Meharry Medical College, Nashville, TN, 37208, USA.
| |
Collapse
|
6
|
Lasunción MA, Martínez-Botas J, Martín-Sánchez C, Busto R, Gómez-Coronado D. Cell cycle dependence on the mevalonate pathway: Role of cholesterol and non-sterol isoprenoids. Biochem Pharmacol 2021; 196:114623. [PMID: 34052188 DOI: 10.1016/j.bcp.2021.114623] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/25/2021] [Accepted: 05/25/2021] [Indexed: 12/16/2022]
Abstract
The mevalonate pathway is responsible for the synthesis of isoprenoids, including sterols and other metabolites that are essential for diverse biological functions. Cholesterol, the main sterol in mammals, and non-sterol isoprenoids are in high demand by rapidly dividing cells. As evidence of its importance, many cell signaling pathways converge on the mevalonate pathway and these include those involved in proliferation, tumor-promotion, and tumor-suppression. As well as being a fundamental building block of cell membranes, cholesterol plays a key role in maintaining their lipid organization and biophysical properties, and it is crucial for the function of proteins located in the plasma membrane. Importantly, cholesterol and other mevalonate derivatives are essential for cell cycle progression, and their deficiency blocks different steps in the cycle. Furthermore, the accumulation of non-isoprenoid mevalonate derivatives can cause DNA replication stress. Identification of the mechanisms underlying the effects of cholesterol and other mevalonate derivatives on cell cycle progression may be useful in the search for new inhibitors, or the repurposing of preexisting cholesterol biosynthesis inhibitors to target cancer cell division. In this review, we discuss the dependence of cell division on an active mevalonate pathway and the role of different mevalonate derivatives in cell cycle progression.
Collapse
Affiliation(s)
- Miguel A Lasunción
- Servicio de Bioquímica-Investigación, Hospital Universitario Ramón y Cajal, IRyCIS, Madrid, Spain; CIBER de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), Spain.
| | - Javier Martínez-Botas
- Servicio de Bioquímica-Investigación, Hospital Universitario Ramón y Cajal, IRyCIS, Madrid, Spain; CIBER de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), Spain
| | - Covadonga Martín-Sánchez
- Servicio de Bioquímica-Investigación, Hospital Universitario Ramón y Cajal, IRyCIS, Madrid, Spain
| | - Rebeca Busto
- Servicio de Bioquímica-Investigación, Hospital Universitario Ramón y Cajal, IRyCIS, Madrid, Spain; CIBER de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), Spain
| | - Diego Gómez-Coronado
- Servicio de Bioquímica-Investigación, Hospital Universitario Ramón y Cajal, IRyCIS, Madrid, Spain; CIBER de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), Spain.
| |
Collapse
|
7
|
Bandyopadhayaya S, Akimov MG, Verma R, Sharma A, Sharma D, Kundu GC, Gretskaya NM, Bezuglov VV, Mandal CC. N-arachidonoyl dopamine inhibits epithelial-mesenchymal transition of breast cancer cells through ERK signaling and decreasing the cellular cholesterol. J Biochem Mol Toxicol 2021; 35:e22693. [PMID: 33393692 DOI: 10.1002/jbt.22693] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 11/04/2020] [Accepted: 12/11/2020] [Indexed: 01/02/2023]
Abstract
N-acyl dopamines (NADAs) are bioactive lipids of the endovanilloid family with known cytotoxicity for the cancer cells; however, the available data on the participation of the endovanilloids in epithelial-mesenchymal transition (EMT) and cancer stemness are controversial. This study unveils the inhibitory role of N-arachidonoyl dopamine (AA-DA), a typical representative of the NADA family, in breast cancer cell migration, EMT, and stemness. AA-DA treatment also led to a decrease in cholesterol biosynthesis gene expressions, and addition of exogenous cholesterol reverted these AA-DA-mediated inhibitory effects. Notably, AA-DA treatment inhibited the key regulatory gene of the cholesterol biosynthesis pathway, sterol regulatory element-binding protein 1 (SREBP1), with concurrent repression of the endoplasmic reticulum kinase 1/2 (ERK1/2) pathway. Furthermore, U0126, an ERK inhibitor, inhibited SREBP1 and decreased cellular cholesterol level, unwinding the molecular mechanism behind AA-DA-mediated anticancer activity. Thus, we, for the first time, revealed that AA-DA counteracts breast cancer EMT via inhibition of ERK signaling and cholesterol content.
Collapse
Affiliation(s)
- Shreetama Bandyopadhayaya
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Ajmer, Rajasthan, India
| | - Mikhail G Akimov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, RAS, Moscow, Russia
| | - Ranjeet Verma
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Ajmer, Rajasthan, India
| | - Ankit Sharma
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Ajmer, Rajasthan, India
| | - Divya Sharma
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Ajmer, Rajasthan, India
| | - Gopal C Kundu
- School of Biotechnology, Institute of Eminence, KIIT Deemed to be University, Bhubaneswar, India
| | - Natalia M Gretskaya
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, RAS, Moscow, Russia
| | - Vladimir V Bezuglov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, RAS, Moscow, Russia
| | - Chandi C Mandal
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Ajmer, Rajasthan, India
| |
Collapse
|
8
|
Jiang T, Zhang G, Lou Z. Role of the Sterol Regulatory Element Binding Protein Pathway in Tumorigenesis. Front Oncol 2020; 10:1788. [PMID: 33014877 PMCID: PMC7506081 DOI: 10.3389/fonc.2020.01788] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Accepted: 08/11/2020] [Indexed: 12/15/2022] Open
Abstract
Metabolic changes are a major feature of tumors, including various metabolic forms, such as energy, lipid, and amino acid metabolism. Sterol regulatory element binding proteins (SREBPs) are important modules in regulating lipid metabolism and play an essential role in metabolic diseases. In the previous decades, the regulatory range of SREBPs has been markedly expanded. It was found that SREBPs also played a critical role in tumor development. SREBPs are involved in energy supply, lipid supply, immune environment and inflammatory environment shaping in tumor cells, and as a protective umbrella to support the malignant proliferation of tumor cells. Natural medicine and traditional Chinese medicine, as an important part of drug therapy, demonstrates the multifaceted effects of SREBPs regulation. This review summarizes the core processes in the involvement of SREBPs in tumors and provides a comprehensive understanding of the pathways through which natural drugs target the SREBP pathway and regulate tumor progression.
Collapse
Affiliation(s)
- Tao Jiang
- School of Basic Medical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Guangji Zhang
- School of Basic Medical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Zhaohuan Lou
- College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| |
Collapse
|
9
|
Li Z, Zhao J, Muhammad N, Wang D, Mao Q, Xia H. Establishment of a HEK293 cell line by CRISPR/Cas9-mediated luciferase knock-in to study transcriptional regulation of the human SREBP1 gene. Biotechnol Lett 2018; 40:1495-1506. [PMID: 30232659 DOI: 10.1007/s10529-018-2608-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Accepted: 09/17/2018] [Indexed: 12/27/2022]
Abstract
OBJECTIVES To establish a HEK293 cell line with a luciferase knock-in reporter controlled by the endogenous SREBP1 promoter for investigating transcriptional regulation of the SREBP1 gene. RESULTS PCR confirmed the site-specific integration of a single copy of the exogenous luciferase gene into one allele of the genome and a 14 bp deletion of the targeted sequence in the other. Luciferase activity was directly correlated with the promoter activity of the endogenous SREBP1 gene in the HEK293-SREBP1-T2A-luciferase-KI cell line cell line. CONCLUSIONS We successfully generated a novel luciferase knock-in reporter system, which will be very useful for studying transcriptional regulation of the SREBP1 gene and for screening drugs or chemical molecules that regulate SREBP1 gene expression.
Collapse
Affiliation(s)
- Zihang Li
- Laboratory of Gene Therapy, Department of Biochemistry, College of Life Sciences, Shaanxi Normal University, 199 South Chang'an Road, Xi'an, 710062, Shaanxi, People's Republic of China
| | - Junli Zhao
- Laboratory of Gene Therapy, Department of Biochemistry, College of Life Sciences, Shaanxi Normal University, 199 South Chang'an Road, Xi'an, 710062, Shaanxi, People's Republic of China
| | - Niaz Muhammad
- Laboratory of Gene Therapy, Department of Biochemistry, College of Life Sciences, Shaanxi Normal University, 199 South Chang'an Road, Xi'an, 710062, Shaanxi, People's Republic of China
| | - Dongyang Wang
- Laboratory of Gene Therapy, Department of Biochemistry, College of Life Sciences, Shaanxi Normal University, 199 South Chang'an Road, Xi'an, 710062, Shaanxi, People's Republic of China
| | - Qinwen Mao
- Department of Pathology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Avenue, Ward 3-140, Chicago, IL, 60611, USA
| | - Haibin Xia
- Laboratory of Gene Therapy, Department of Biochemistry, College of Life Sciences, Shaanxi Normal University, 199 South Chang'an Road, Xi'an, 710062, Shaanxi, People's Republic of China.
| |
Collapse
|
10
|
Zeng Y, Xiao D, He H, He J, Pan H, Yang W, Chen Y, He J. SERINC2-knockdown inhibits proliferation, migration and invasion in lung adenocarcinoma. Oncol Lett 2018; 16:5916-5922. [PMID: 30405754 PMCID: PMC6202524 DOI: 10.3892/ol.2018.9403] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 07/16/2018] [Indexed: 12/24/2022] Open
Abstract
Serine incorporator 2 (SERINC2) is a member of the SERINC family of transmembrane proteins that incorporate serine into membrane lipids during synthesis. In the present study, the biological function of SERINC2 in lung adenocarcinoma cells was investigated. The data from a previous study and the publicly available Oncomine database were analysed regarding the expression levels of SERINC2 mRNA in lung adenocarcinoma. A lentiviral-based short hairpin RNA (shRNA) was used to suppress SERINC2 expression in lung cancer cells. The effect of SERINC2 expression on lung cancer proliferation was determined using cell counting kit-8 and colony formation assays. The influence on invasion and migration was examined in vitro using Transwell and wound-healing assays, respectively. Phosphorylated protein kinase B (p-AKT) expression levels were assessed by immunoblotting. According to a previous study and Oncomine, expression levels of SERINC2 mRNA are significantly upregulated in tumour tissues compared with those in healthy tissues in patients with lung adenocarcinoma. SERINC2-knockdown by lentiviral-based shRNA inhibited the proliferation, migration and invasion of the H1650 and A549 cells. In addition, p-AKT expression levels were significantly decreased following SERINC2-knockdown. In conclusion, SERINC2-knockdown suppresses lung adenocarcinoma proliferation, migration and invasion through a mechanism that may be associated with phosphatidylinositol 3-kinase/AKT signalling. Based on these findings, SERINC2 serves an important role in the progression of lung adenocarcinoma.
Collapse
Affiliation(s)
- Yuan Zeng
- Department of Thoracic Surgery, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120, P.R. China.,State Key Laboratory of Respiratory Diseases and National Clinical Research Center for Respiratory Disease and Guangzhou Institute of Respiratory Diseases, Guangzhou, Guangdong 510000, P.R. China
| | - Dakai Xiao
- Department of Thoracic Surgery, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120, P.R. China.,State Key Laboratory of Respiratory Diseases and National Clinical Research Center for Respiratory Disease and Guangzhou Institute of Respiratory Diseases, Guangzhou, Guangdong 510000, P.R. China
| | - Huiming He
- Department of Thoracic Surgery, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120, P.R. China.,State Key Laboratory of Respiratory Diseases and National Clinical Research Center for Respiratory Disease and Guangzhou Institute of Respiratory Diseases, Guangzhou, Guangdong 510000, P.R. China
| | - Jiaxi He
- Department of Thoracic Surgery, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120, P.R. China.,State Key Laboratory of Respiratory Diseases and National Clinical Research Center for Respiratory Disease and Guangzhou Institute of Respiratory Diseases, Guangzhou, Guangdong 510000, P.R. China
| | - Hui Pan
- Department of Thoracic Surgery, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120, P.R. China.,State Key Laboratory of Respiratory Diseases and National Clinical Research Center for Respiratory Disease and Guangzhou Institute of Respiratory Diseases, Guangzhou, Guangdong 510000, P.R. China
| | - Wei Yang
- Department of Cardiothoracic Surgery, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330008, P.R. China
| | - Yaoqi Chen
- Department of Thoracic Surgery, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120, P.R. China.,State Key Laboratory of Respiratory Diseases and National Clinical Research Center for Respiratory Disease and Guangzhou Institute of Respiratory Diseases, Guangzhou, Guangdong 510000, P.R. China
| | - Jianxing He
- Department of Thoracic Surgery, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510120, P.R. China.,State Key Laboratory of Respiratory Diseases and National Clinical Research Center for Respiratory Disease and Guangzhou Institute of Respiratory Diseases, Guangzhou, Guangdong 510000, P.R. China
| |
Collapse
|
11
|
Abstract
Cellular lipid metabolism and homeostasis are controlled by sterol regulatory-element binding proteins (SREBPs). In addition to performing canonical functions in the transcriptional regulation of genes involved in the biosynthesis and uptake of lipids, genome-wide system analyses have revealed that these versatile transcription factors act as important nodes of convergence and divergence within biological signalling networks. Thus, they are involved in myriad physiological and pathophysiological processes, highlighting the importance of lipid metabolism in biology. Changes in cell metabolism and growth are reciprocally linked through SREBPs. Anabolic and growth signalling pathways branch off and connect to multiple steps of SREBP activation and form complex regulatory networks. In addition, SREBPs are implicated in numerous pathogenic processes such as endoplasmic reticulum stress, inflammation, autophagy and apoptosis, and in this way, they contribute to obesity, dyslipidaemia, diabetes mellitus, nonalcoholic fatty liver disease, nonalcoholic steatohepatitis, chronic kidney disease, neurodegenerative diseases and cancers. This Review aims to provide a comprehensive understanding of the role of SREBPs in physiology and pathophysiology at the cell, organ and organism levels.
Collapse
Affiliation(s)
- Hitoshi Shimano
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
- Life Science Center, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba 305-8577, Japan
- AMED-CREST, Japan Agency for Medical Research and Development, Chiyoda-ku, Tokyo 100-0004, Japan
| | - Ryuichiro Sato
- AMED-CREST, Japan Agency for Medical Research and Development, Chiyoda-ku, Tokyo 100-0004, Japan
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan
| |
Collapse
|
12
|
Engelking LJ, Cantoria MJ, Xu Y, Liang G. Developmental and extrahepatic physiological functions of SREBP pathway genes in mice. Semin Cell Dev Biol 2017; 81:98-109. [PMID: 28736205 DOI: 10.1016/j.semcdb.2017.07.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 07/07/2017] [Indexed: 12/17/2022]
Abstract
Sterol regulatory element-binding proteins (SREBPs), master transcriptional regulators of cholesterol and fatty acid synthesis, have been found to contribute to a diverse array of cellular processes. In this review, we focus on genetically engineered mice in which the activities of six components of the SREBP gene pathway, namely SREBP-1, SREBP-2, Scap, Insig-1, Insig-2, or Site-1 protease have been altered through gene knockout or transgenic approaches. In addition to the expected impacts on lipid metabolism, manipulation of these genes in mice is found to affect a wide array of developmental and physiologic processes ranging from interferon signaling in macrophages to synaptic transmission in the brain. The findings reviewed herein provide a blueprint to guide future studies defining the complex interactions between lipid biology and the physiologic processes of many distinct organ systems.
Collapse
Affiliation(s)
- Luke J Engelking
- Departments of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Mary Jo Cantoria
- Departments of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Yanchao Xu
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Guosheng Liang
- Departments of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| |
Collapse
|
13
|
Zhang C, Liu J, Huang G, Zhao Y, Yue X, Wu H, Li J, Zhu J, Shen Z, Haffty BG, Hu W, Feng Z. Cullin3-KLHL25 ubiquitin ligase targets ACLY for degradation to inhibit lipid synthesis and tumor progression. Genes Dev 2017; 30:1956-70. [PMID: 27664236 PMCID: PMC5066239 DOI: 10.1101/gad.283283.116] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 08/16/2016] [Indexed: 12/27/2022]
Abstract
ATP-citrate lyase (ACLY), a key enzyme for lipid synthesis, is frequently overexpressed or activated in cancer to promote lipid synthesis and tumor progression. Zhang et al. show that Cullin3 (CUL3), a core protein of the CUL3–RING ubiquitin ligase complex, interacts with ACLY through its adaptor protein, KLHL25, to ubiquitinate and degrade ACLY in cells. Through negative regulation of ACLY, CUL3 inhibits lipid synthesis, cell proliferation, and tumor growth in lung cancer cells. Increased lipid synthesis is a key characteristic of many cancers that is critical for cancer progression. ATP-citrate lyase (ACLY), a key enzyme for lipid synthesis, is frequently overexpressed or activated in cancer to promote lipid synthesis and tumor progression. Cullin3 (CUL3), a core protein for the CUL3–RING ubiquitin ligase complex, has been reported to be a tumor suppressor and frequently down-regulated in lung cancer. Here, we found that CUL3 interacts with ACLY through its adaptor protein, KLHL25 (Kelch-like family member 25), to ubiquitinate and degrade ACLY in cells. Through negative regulation of ACLY, CUL3 inhibits lipid synthesis, cell proliferation, and xenograft tumor growth of lung cancer cells. Furthermore, ACLY inhibitor SB-204990 greatly abolishes the promoting effect of CUL3 down-regulation on lipid synthesis, cell proliferation, and tumor growth. Importantly, low CUL3 expression is associated with high ACLY expression and poor prognosis in human lung cancer. In summary, our results identify CUL3–KLHL25 ubiquitin ligase as a novel negative regulator for ACLY and lipid synthesis and demonstrate that decreased CUL3 expression is an important mechanism for increased ACLY expression and lipid synthesis in lung cancer. These results also reveal that negative regulation of ACLY and lipid synthesis is a novel and critical mechanism for CUL3 in tumor suppression.
Collapse
Affiliation(s)
- Cen Zhang
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey 08903, USA
| | - Juan Liu
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey 08903, USA
| | - Grace Huang
- Nelson Institute of Environmental Medicine, New York University School of Medicine, New York University, Tuxedo, New Jersey 10987, USA
| | - Yuhan Zhao
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey 08903, USA
| | - Xuetian Yue
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey 08903, USA
| | - Hao Wu
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey 08903, USA
| | - Jun Li
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey 08903, USA
| | - Junlan Zhu
- Nelson Institute of Environmental Medicine, New York University School of Medicine, New York University, Tuxedo, New Jersey 10987, USA
| | - Zhiyuan Shen
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey 08903, USA
| | - Bruce G Haffty
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey 08903, USA
| | - Wenwei Hu
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey 08903, USA
| | - Zhaohui Feng
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, Rutgers University, The State University of New Jersey, New Brunswick, New Jersey 08903, USA; Department of Pharmacology, Rutgers University, The State University of New Jersey, Piscataway, New Jersey 08854, USA
| |
Collapse
|
14
|
The Combination of Blueberry Juice and Probiotics Ameliorate Non-Alcoholic Steatohepatitis (NASH) by Affecting SREBP-1c/PNPLA-3 Pathway via PPAR-α. Nutrients 2017; 9:nu9030198. [PMID: 28264426 PMCID: PMC5372861 DOI: 10.3390/nu9030198] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Revised: 02/14/2017] [Accepted: 02/21/2017] [Indexed: 12/19/2022] Open
Abstract
Nonalcoholic steatohepatitis (NASH) is liver inflammation and a major threat to public health. Several pharmaceutical agents have been used for NASH therapy but their high-rate side effects limit the use. Blueberry juice and probiotics (BP) have anti-inflammation and antibacterial properties, and may be potential candidates for NASH therapy. To understand the molecular mechanism, Sprague Dawley rats were used to create NASH models and received different treatments. Liver tissues were examined using HE (hematoxylin and eosin) and ORO (Oil Red O) stain, and serum biochemical indices were measured. The levels of peroxisome proliferators-activated receptor (PPAR)-α, sterol regulatory element binding protein-1c (SREBP-1c), Patatin-like phospholipase domain-containing protein 3 (PNPLA-3), inflammatory cytokines and apoptosis biomarkers in liver tissues were measured by qRT-PCR and Western blot. HE and ORO analysis indicated that the hepatocytes were seriously damaged with more and larger lipid droplets in NASH models while BP reduced the number and size of lipid droplets (p < 0.05). Meanwhile, BP increased the levels of SOD (superoxide dismutase), GSH (reduced glutathione) and HDL-C (high-density lipoprotein cholesterol), and reduced the levels of AST (aspartate aminotransferase), ALT (alanine aminotransferase), TG (triglycerides), LDL-C (low-density lipoprotein cholesterol) and MDA (malondialdehyde) in NASH models (p < 0.05). BP increased the level of PPAR-α (Peroxisome proliferator-activated receptor α), and reduced the levels of SREBP-1c (sterol regulatory element binding protein-1c) and PNPLA-3 (Patatin-like phospholipase domain-containing protein 3) (p < 0.05). BP reduced hepatic inflammation and apoptosis by affecting IL-6 (interleukin 6), TNF-α (Tumor necrosis factor α), caspase-3 and Bcl-2 in NASH models. Furthermore, PPAR-α inhibitor increased the level of SREBP-1c and PNPLA-3. Therefore, BP prevents NASH progression by affecting SREBP-1c/PNPLA-3 pathway via PPAR-α.
Collapse
|
15
|
Masri S. Metabolic demand of the hepatic cell cycle. Cell Cycle 2016; 15:3020-3021. [PMID: 27485093 DOI: 10.1080/15384101.2016.1216924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Affiliation(s)
- Selma Masri
- a Center for Epigenetics and Metabolism, Department of Biological Chemistry, University of California , Irvine, Irvine , CA , USA
| |
Collapse
|
16
|
Li Y, Jing C, Tang X, Chen Y, Han X, Zhu Y. LXR activation causes G1/S arrest through inhibiting SKP2 expression in MIN6 pancreatic beta cells. Endocrine 2016; 53:689-700. [PMID: 27071658 DOI: 10.1007/s12020-016-0915-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 03/02/2016] [Indexed: 11/24/2022]
Abstract
Liver X receptors (LXRs) are nuclear hormone receptors with central roles in lipid homeostasis. We previously showed that LXR activation induced aberrant lipid metabolism and G1 cell cycle arrest in pancreatic beta cells. In this study, we aimed to identify the molecular target of LXR causing G1 arrest. LXR activation was induced by its agonist, T0901317. A series of luciferase reporters of truncated Skp2 promoter were analyzed in MIN6 cells. mRNA and protein levels of SKP2 and P27 were detected. Flow cytometry assay was used to determine the cell cycle distribution. MTT assay was used to evaluate cell viability. LXR activation increased cell distribution in G1 phase and lipid accumulation. Since dominant-negative Srebp1c could clear the deposited lipid rather than recover the G1 arrest, we identified S-phase kinase-associated protein 2 (Skp2) as a potential target gene of LXR. In deed, LXR activation significantly inhibited Skp2 gene expression and protein amount. We also observed that the luciferase activity of Skp2 promoter was suppressed by T0901317 and the potential LXR regulatory site was narrowed down to a region of nt -289 to -38. Silencing Lxrα and Lxrβ rescued SKP2 protein level and recovered the cellular growth repressed by LXR activation. Moreover, SKP2 overabundance reduced P27 protein level by promoting its degradation, consequently overcame the G1 arrest caused by T0901317. Our findings demonstrate that transrepressing Skp2 expression by LXR activation resulted in defective SKP2-mediated P27 degradation and inhibitory cell growth in beta cells.
Collapse
Affiliation(s)
- Yating Li
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Department of Biochemistry and Molecular Biology, Nanjing Medical University, 140 Hanzhong Road, Nanjing, 210029, People's Republic of China
| | - Changwen Jing
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Department of Biochemistry and Molecular Biology, Nanjing Medical University, 140 Hanzhong Road, Nanjing, 210029, People's Republic of China
| | - Xinyi Tang
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Department of Biochemistry and Molecular Biology, Nanjing Medical University, 140 Hanzhong Road, Nanjing, 210029, People's Republic of China
| | - Yuanyuan Chen
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Department of Biochemistry and Molecular Biology, Nanjing Medical University, 140 Hanzhong Road, Nanjing, 210029, People's Republic of China
| | - Xiao Han
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Department of Biochemistry and Molecular Biology, Nanjing Medical University, 140 Hanzhong Road, Nanjing, 210029, People's Republic of China
| | - Yunxia Zhu
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Department of Biochemistry and Molecular Biology, Nanjing Medical University, 140 Hanzhong Road, Nanjing, 210029, People's Republic of China.
| |
Collapse
|
17
|
Bao J, Zhu L, Zhu Q, Su J, Liu M, Huang W. SREBP-1 is an independent prognostic marker and promotes invasion and migration in breast cancer. Oncol Lett 2016; 12:2409-2416. [PMID: 27703522 PMCID: PMC5038874 DOI: 10.3892/ol.2016.4988] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 06/29/2016] [Indexed: 12/21/2022] Open
Abstract
Re-programming of lipogenic signaling has been previously demonstrated to result in significant alterations in tumor cell pathology. Sterol regulatory element-binding protein 1 (SREBP-1) is a known transcription factor of lipogenic genes. Despite the fact that its functions in proliferation and apoptosis have been elucidated in recent studies, its role in tumor cell migration and invasion, particularly in breast cancer, remains unclear. In present study, the messenger RNA and protein expression levels of SREBP-1 in cancer tissues were observed to be overexpressed compared with those in matched para-cancerous tissues (P<0.01). SREBP-1 level was highly positively correlated with tumor differentiation (P<0.001), tumor-node-metastasis stage (P=0.044) and lymph node metastasis (P<0.001). High expression of SREBP-1 predicted poor prognosis in patients with breast cancer. Additionally, multivariate analysis revealed that SREBP-1 was an independent factor of 5-year overall and disease-specific survival in breast cancer patients (P<0.01). In vitro studies revealed that the suppression of SREBP-1 expression in both MDA-MB-231 and MCF7 cells significantly inhibited cell migration and invasion (P<0.01). The present data indicate that SREBP-1 plays a critical role in breast cancer migration and invasion, and may serve as a prognostic marker of this malignancy.
Collapse
Affiliation(s)
- Jisheng Bao
- Department of Geriatrics, Nanjing Medical University Affiliated Wuxi Second Hospital, Wuxi, Jiangsu 214002, P.R. China
| | - Liping Zhu
- Department of Internal Medicine, Nanjing Medical University Affiliated Wuxi Second Hospital, Wuxi, Jiangsu 214002, P.R. China
| | - Qi Zhu
- Department of Internal Medicine, Nanjing Medical University Affiliated Wuxi Second Hospital, Wuxi, Jiangsu 214002, P.R. China
| | - Jianhua Su
- Department of Geriatrics, Nanjing Medical University Affiliated Wuxi Second Hospital, Wuxi, Jiangsu 214002, P.R. China
| | - Menglan Liu
- Department of Geriatrics, Nanjing Medical University Affiliated Wuxi Second Hospital, Wuxi, Jiangsu 214002, P.R. China
| | - Wei Huang
- Department of Geriatrics, Nanjing Medical University Affiliated Wuxi Second Hospital, Wuxi, Jiangsu 214002, P.R. China
| |
Collapse
|
18
|
Fischer S, Mathias S, Schaz S, Emmerling VV, Buck T, Kleemann M, Hackl M, Grillari J, Aschrafi A, Handrick R, Otte K. Enhanced protein production by microRNA-30 family in CHO cells is mediated by the modulation of the ubiquitin pathway. J Biotechnol 2015; 212:32-43. [PMID: 26256096 DOI: 10.1016/j.jbiotec.2015.08.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 07/31/2015] [Accepted: 08/04/2015] [Indexed: 12/20/2022]
Abstract
Functional genomics represent a valuable approach to improve culture performance of Chinese hamster ovary (CHO) cell lines for biopharmaceutical manufacturing. Recent advances in applied microRNA (miRNAs) research suggest that these small non-coding RNAs are critical for the regulation of cell phenotypes in CHO cells. However, the notion that individual miRNAs usually control the expression of hundreds of different genes makes miRNA target identification highly complex. We have recently reported that the entire miR-30 family enhances recombinant protein production in CHO cells. To better understand the pro-productive effects of this miRNA family, we set out to identify their downstream target genes in CHO cells. Computational target prediction combined with a comprehensive functional validation enabled the discovery of a set of twenty putative target genes for all productivity enhancing miR-30 family members. We demonstrate that all miR-30 isoforms contribute to the regulation of the ubiquitin pathway in CHO cells by directly targeting the ubiquitin E3 ligase S-phase kinase-associated protein 2 (Skp2). Finally, we provide several lines of evidence that miR-30-mediated modulation of the ubiquitin pathway may enhance recombinant protein expression in CHO cells. In summary, this study supports the importance of non-coding RNAs, especially of miRNAs, in the context of cell line engineering.
Collapse
Affiliation(s)
- Simon Fischer
- Institute of Applied Biotechnology, University of Applied Sciences Biberach, Hubertus-Liebrecht-Strasse 35, 88400 Biberach, Germany; University of Ulm, Faculty of Medicine, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
| | - Sven Mathias
- Institute of Applied Biotechnology, University of Applied Sciences Biberach, Hubertus-Liebrecht-Strasse 35, 88400 Biberach, Germany; University of Ulm, Faculty of Natural Sciences, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
| | - Simone Schaz
- Institute of Applied Biotechnology, University of Applied Sciences Biberach, Hubertus-Liebrecht-Strasse 35, 88400 Biberach, Germany; University of Ulm, Faculty of Natural Sciences, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
| | - Verena Vanessa Emmerling
- University of Ulm, Faculty of Medicine, Albert-Einstein-Allee 11, 89081 Ulm, Germany; Rentschler Biotechnologie GmbH, Erwin-Rentschler-Straße 21, 88471 Laupheim, Germany.
| | - Theresa Buck
- Institute of Applied Biotechnology, University of Applied Sciences Biberach, Hubertus-Liebrecht-Strasse 35, 88400 Biberach, Germany.
| | - Michael Kleemann
- Institute of Applied Biotechnology, University of Applied Sciences Biberach, Hubertus-Liebrecht-Strasse 35, 88400 Biberach, Germany.
| | | | - Johannes Grillari
- Department of Biotechnology, BOKU University of Natural Resources and Life Sciences, Muthgasse 11, 1190 Vienna, Austria; Evercyte GmbH, Muthgasse 18, 1190 Vienna, Austria.
| | - Armaz Aschrafi
- Department of Neuroinformatics, Donders Institute for Brain Function, Cognition and Behaviour, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands.
| | - René Handrick
- Institute of Applied Biotechnology, University of Applied Sciences Biberach, Hubertus-Liebrecht-Strasse 35, 88400 Biberach, Germany.
| | - Kerstin Otte
- Institute of Applied Biotechnology, University of Applied Sciences Biberach, Hubertus-Liebrecht-Strasse 35, 88400 Biberach, Germany.
| |
Collapse
|
19
|
Guo D, Bell EH, Mischel P, Chakravarti A. Targeting SREBP-1-driven lipid metabolism to treat cancer. Curr Pharm Des 2015; 20:2619-26. [PMID: 23859617 DOI: 10.2174/13816128113199990486] [Citation(s) in RCA: 213] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 06/24/2013] [Indexed: 01/17/2023]
Abstract
Metabolic reprogramming is a hallmark of cancer. Oncogenic growth signaling regulates glucose, glutamine and lipid metabolism to meet the bioenergetics and biosynthetic demands of rapidly proliferating tumor cells. Emerging evidence indicates that sterol regulatory element-binding protein 1 (SREBP-1), a master transcription factor that controls lipid metabolism, is a critical link between oncogenic signaling and tumor metabolism. We recently demonstrated that SREBP-1 is required for the survival of mutant EGFR-containing glioblastoma, and that this pro-survival metabolic pathway is mediated, in part, by SREBP-1-dependent upregulation of the fatty acid synthesis and low density lipoprotein (LDL) receptor (LDLR). These results have identified EGFR/PI3K/Akt/SREBP-1 signaling pathway that promotes growth and survival in glioblastoma, and potentially other cancer types. Here, we summarize recent insights in the understanding of cancer lipid metabolism, and discuss the evidence linking SREBP-1 with PI3K/Akt signaling-controlled glycolysis and with Myc-regulated glutaminolysis to lipid metabolism. We also discuss the development of potential drugs targeting the SREBP-1- driven lipid metabolism as anti-cancer agents.
Collapse
Affiliation(s)
| | | | | | - Arnab Chakravarti
- Department of Radiation Oncology, Ohio State University Comprehensive Cancer Center and Arthur G. James Cancer Hospital, Columbus, OH 43210, USA.
| |
Collapse
|
20
|
SREBP-1 has a prognostic role and contributes to invasion and metastasis in human hepatocellular carcinoma. Int J Mol Sci 2014; 15:7124-38. [PMID: 24776759 PMCID: PMC4057663 DOI: 10.3390/ijms15057124] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Revised: 03/16/2014] [Accepted: 04/10/2014] [Indexed: 01/18/2023] Open
Abstract
Sterol regulatory element-binding protein 1 (SREBP-1) is a well-known nuclear transcription factor involved in lipid synthesis. Recent studies have focused on its functions in tumor cell proliferation and apoptosis, but its role in cell migration and invasion, especially in hepatocellular carcinoma (HCC), is still unclear. In this study, we found that the expression of SREBP-1 in HCC tissues was significantly higher than those in matched tumor-adjacent tissues (p < 0.05). SREBP-1 was expressed at significantly higher levels in patients with large tumor size, high histological grade and advanced tumor-node-metastasis (TNM) stage (p < 0.05). The positive expression of SREBP-1 correlated with a worse 3-year overall and disease-free survival of HCC patients (p < 0.05). Additionally, SREBP-1 was an independent factor for predicting both 3-year overall and disease-free survival of HCC patients (p < 0.05). In vitro studies revealed that downregulation of SREBP-1 inhibited cell proliferation and induced apoptosis in both HepG2 and MHCC97L cells (p < 0.05). Furthermore, wound healing and transwell assays showed that SREBP-1 knockdown prominently inhibited cell migration and invasion in both HepG2 and MHCC97L cells (p < 0.05). These results suggest that SREBP-1 may serve as a prognostic marker in HCC and may promote tumor progression by promoting cell growth and metastasis.
Collapse
|
21
|
Stable SREBP-1a knockdown decreases the cell proliferation rate in human preadipocyte cells without inducing senescence. Biochem Biophys Res Commun 2014; 447:51-6. [DOI: 10.1016/j.bbrc.2014.03.104] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 03/20/2014] [Indexed: 11/18/2022]
|
22
|
REN WEIHUA, YANG CHENYI, YANG XIANMEI, YU LONG. siRNA-mediated knockdown of hTDE2 retards cell cycle progression through transcriptional activation of p21. Oncol Rep 2014; 31:1314-22. [DOI: 10.3892/or.2014.2980] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 11/25/2013] [Indexed: 11/06/2022] Open
|
23
|
Post-lanosterol biosynthesis of cholesterol and cancer. Curr Opin Pharmacol 2012; 12:717-23. [DOI: 10.1016/j.coph.2012.07.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2012] [Revised: 06/29/2012] [Accepted: 07/03/2012] [Indexed: 12/13/2022]
|
24
|
Iwakiri Y. A role of miR-33 for cell cycle progression and cell proliferation. Cell Cycle 2012; 11:1057-8. [PMID: 22395363 DOI: 10.4161/cc.11.6.19744] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Affiliation(s)
- Yasuko Iwakiri
- Section of Digestive Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA.
| |
Collapse
|
25
|
Cirera-Salinas D, Pauta M, Allen RM, Salerno AG, Ramírez CM, Chamorro-Jorganes A, Wanschel AC, Lasuncion MA, Morales-Ruiz M, Suarez Y, Baldan Á, Esplugues E, Fernández-Hernando C. Mir-33 regulates cell proliferation and cell cycle progression. Cell Cycle 2012; 11:922-33. [PMID: 22333591 DOI: 10.4161/cc.11.5.19421] [Citation(s) in RCA: 134] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Cholesterol metabolism is tightly regulated at the cellular level and is essential for cellular growth. microRNAs (miRNAs), a class of noncoding RNAs, have emerged as critical regulators of gene expression, acting predominantly at posttranscriptional level. Recent work from our group and others has shown that hsa-miR-33a and hsa-miR-33b, miRNAs located within intronic sequences of the Srebp genes, regulate cholesterol and fatty acid metabolism in concert with their host genes. Here, we show that hsa-miR-33 family members modulate the expression of genes involved in cell cycle regulation and cell proliferation. MiR-33 inhibits the expression of the cyclin-dependent kinase 6 (CDK6) and cyclin D1 (CCND1), thereby reducing cell proliferation and cell cycle progression. Overexpression of miR-33 induces a significant G 1 cell cycle arrest in Huh7 and A549 cell lines. Most importantly, inhibition of miR-33 expression using 2'fluoro/methoxyethyl-modified (2'F/MOE-modified) phosphorothioate backbone antisense oligonucleotides improves liver regeneration after partial hepatectomy (PH) in mice, suggesting an important role for miR-33 in regulating hepatocyte proliferation during liver regeneration. Altogether, these results suggest that Srebp/miR-33 locus may cooperate to regulate cell proliferation, cell cycle progression and may also be relevant to human liver regeneration.
Collapse
Affiliation(s)
- Daniel Cirera-Salinas
- Department of Medicine, Leon H. Charney Division of Cardiology and Cell Biology and Marc and Ruti Bell Vascular Biology and Disease Program, New York University School of Medicine, New York, NY, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Delgado-Coello B, Briones-Orta MA, Macías-Silva M, Mas-Oliva J. Cholesterol: recapitulation of its active role during liver regeneration. Liver Int 2011; 31:1271-84. [PMID: 21745289 DOI: 10.1111/j.1478-3231.2011.02542.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Liver regeneration is a compensatory hyperplasia produced by several stimuli that promotes proliferation in order to provide recovery of the liver mass and architecture. This process involves complex signalling cascades that receive feedback from autocrine and paracrine pathways, recognized by parenchymal as well as non-parenchymal cells. Nowadays the dynamic role of lipids in biological processes is widely recognized; however, a systematic analysis of their importance during liver regeneration is still missing. Therefore, in this review we address the role of lipids including the bioactive ones such as sphingolipids, but with special emphasis on cholesterol. Cholesterol is not only considered as a structural component but also as a relevant lipid involved in the control of the intermediate metabolism of different liver cell types such as hepatocytes, hepatic stellate cells and Kupffer cells. Cholesterol plays a significant role at the level of specific membrane domains, as well as modulating the expression of sterol-dependent proteins. Moreover, several enzymes related to the catabolism of cholesterol and whose activity is down regulated are related to the protection of liver tissue from toxicity during the process of regeneration. This review puts in perspective the necessity to study and understand the basic mechanisms involving lipids during the process of liver regeneration. On the other hand, the knowledge acquired in this area in the past years, can be considered invaluable in order to provide further insights into processes such as general organogenesis and several liver-related pathologies, including steatosis and fibrosis.
Collapse
Affiliation(s)
- Blanca Delgado-Coello
- Departamento de Bioquímica y Biología Estructural, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México, DF Mexico
| | | | | | | |
Collapse
|
27
|
Kumadaki S, Karasawa T, Matsuzaka T, Ema M, Nakagawa Y, Nakakuki M, Saito R, Yahagi N, Iwasaki H, Sone H, Takekoshi K, Yatoh S, Kobayashi K, Takahashi A, Suzuki H, Takahashi S, Yamada N, Shimano H. Inhibition of ubiquitin ligase F-box and WD repeat domain-containing 7α (Fbw7α) causes hepatosteatosis through Krüppel-like factor 5 (KLF5)/peroxisome proliferator-activated receptor γ2 (PPARγ2) pathway but not SREBP-1c protein in mice. J Biol Chem 2011; 286:40835-46. [PMID: 21911492 DOI: 10.1074/jbc.m111.235283] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
F-box and WD repeat domain-containing 7α (Fbw7α) is the substrate recognition component of a ubiquitin ligase that controls the degradation of factors involved in cellular growth, including c-Myc, cyclin E, and c-Jun. In addition, Fbw7α degrades the nuclear form of sterol regulatory element-binding protein (SREBP)-1a, a global regulator of lipid synthesis, particularly during mitosis in cultured cells. This study investigated the in vivo role of Fbw7α in hepatic lipid metabolism. siRNA knockdown of Fbw7α in mice caused marked hepatosteatosis with the accumulation of triglycerides. However, inhibition of Fbw7α did not change the level of nuclear SREBP-1 protein or the expression of genes involved in fatty acid synthesis and oxidation. In vivo experiments on the gain and loss of Fbw7α function indicated that Fbw7α regulated the expression of peroxisome proliferator-activated receptor (PPAR) γ2 and its target genes involved in fatty acid uptake and triglyceride synthesis. These genes included fatty acid transporter Cd36, diacylglycerol acyltransferase 1 (Dgat1), and fat-specific protein 27 (Cidec). The regulation of PPARγ2 by Fbw7α was mediated, at least in part, by the direct degradation of the Krüppel-like factor 5 (KLF5) protein, upstream of PPARγ2 expression. Hepatic Fbw7α contributes to normal fatty acid and triglyceride metabolism, functions that represent novel aspects of this cell growth regulator.
Collapse
Affiliation(s)
- Shin Kumadaki
- Department of Internal Medicine (Endocrinology and Metabolism), Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Dong P, Flores J, Pelton K, Solomon KR. Prohibitin is a cholesterol-sensitive regulator of cell cycle transit. J Cell Biochem 2011; 111:1367-74. [PMID: 20830747 DOI: 10.1002/jcb.22865] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cholesterol is essential in establishing most functional animal cell membranes; cells cannot grow or proliferate in the absence of sufficient cholesterol. Consequently, almost every cell, tissue, and animal tightly regulates cholesterol homeostasis, including complex mechanisms of synthesis, transport, uptake, and disposition of cholesterol molecules. We hypothesize that cellular recognition of cholesterol insufficiency causes cell cycle arrest in order to avoid a catastrophic failure in membrane synthesis. Here, we demonstrate using unbiased proteomics and standard biochemistry that cholesterol insufficiency causes upregulation of prohibitin, an inhibitor of cell cycle progression, through activation of a cholesterol-responsive promoter element. We also demonstrate that prohibitin protects cells from apoptosis caused by cholesterol insufficiency. This is the first study tying cholesterol homeostasis to a specific cell cycle regulator that inhibits apoptosis.
Collapse
Affiliation(s)
- Pei Dong
- Department of Orthopaedic Surgery, Children's Hospital Boston, 300 Longwood Avenue, Boston, Massachusetts 02115, USA
| | | | | | | |
Collapse
|
29
|
Lewis CA, Griffiths B, Santos CR, Pende M, Schulze A. Genetic ablation of S6-kinase does not prevent processing of SREBP1. ACTA ACUST UNITED AC 2010; 51:280-90. [PMID: 21093473 DOI: 10.1016/j.advenzreg.2010.09.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Accepted: 09/06/2010] [Indexed: 11/19/2022]
Abstract
The SREBP family of transcription factors regulates the expression of genes involved in fatty acid and cholesterol biosynthesis. The activation of SREBP transcription factors requires proteolytic cleavage of the inactive precursor and nuclear translocation of the mature form of the protein. It has been shown that nuclear accumulation of the mature form of SREBP1 is induced in response to activation of the serine/threonine kinase Akt, an important effector of the Ras/PI3-kinase signalling pathway. Activation of SREBP by Akt depends on the mammalian target of rapamycin complex 1 (mTORC1) but the exact mechanism of this activation remains unclear. We have investigated whether ablation of different signalling molecules downstream of mTORC1 affects expression of SREBP targets genes. We could show that inhibition of S6-kinases 1 and 2 expression using RNA interference did not block induction of expression of fatty acid synthase (FASN) or ATP-citrate lyase (ACLY) following activation of Akt in human retinal pigment epithelial cells. Furthermore, accumulation of mature SREBP1 was not inhibited after combined silencing of S6-kinases 1 and 2. Genetic ablation of both kinases also did not prevent the formation of mature SREBP1 in mouse embryonic fibroblasts. Taken together, these results suggest that S6-kinases 1 and 2 are dispensable for the induction of SREBP processing in the experimental systems used here.
Collapse
Affiliation(s)
- Caroline A Lewis
- Gene Expression Analysis Laboratory, Cancer Research UK London Research Institute, London, UK
| | | | | | | | | |
Collapse
|
30
|
Kim YM, Shin HT, Seo YH, Byun HO, Yoon SH, Lee IK, Hyun DH, Chung HY, Yoon G. Sterol regulatory element-binding protein (SREBP)-1-mediated lipogenesis is involved in cell senescence. J Biol Chem 2010; 285:29069-77. [PMID: 20615871 DOI: 10.1074/jbc.m110.120386] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Increased cell mass is one of the characteristics of senescent cells, but this event has not been clearly defined. When subcellular organellar mass was estimated with organelle-specific fluorescence dyes, we observed that most membranous organelles progressively increase in mass during cell senescence. This increase was accompanied by an increase in membrane lipids and augmented expression of lipogenic enzymes, such as fatty acid synthase (FAS), ATP citrate lyase, and acetyl-CoA carboxylase. The mature form of sterol regulatory element-binding protein (SREBP)-1 was also elevated. Increased expression of these lipogenic effectors was further observed in the liver tissues of aging Fischer 344 rats. Ectopic expression of mature form of SREBP-1 in both Chang cells and primary young human diploid fibroblasts was enough to induce senescence. Blocking lipogenesis with FAS inhibitors (cerulenin and C75) and via siRNA-mediated silencing of SREBP-1 and ATP citrate lyase significantly attenuated H(2)O(2)-induced senescence. Finally, old human diploid fibroblasts were effectively reversed to young-like cells by challenging with FAS inhibitors. Our results suggest that enhanced lipogenesis is not only a common event, but also critically involved in senescence via SREBP-1 induction, thereby contributing to the increase in organelle mass (as a part of cell mass), a novel indicator of senescence.
Collapse
Affiliation(s)
- You-Mie Kim
- Department of Biochemistry and Molecular Biology, School of Medicine, Ajou University, Suwon 443-721, Korea
| | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Moranova Z, Kawamoto S, Raclavsky V. HYPOXIA SENSING IN CRYPTOCOCCUS NEOFORMANS: BIOFILM-LIKE ADAPTATION FOR DORMANCY? Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2009; 153:189-93. [DOI: 10.5507/bp.2009.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
|
32
|
Genome-wide analysis of SREBP-1 binding in mouse liver chromatin reveals a preference for promoter proximal binding to a new motif. Proc Natl Acad Sci U S A 2009; 106:13765-9. [PMID: 19666523 DOI: 10.1073/pnas.0904246106] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Lipid homeostasis in vertebrates is regulated by 3 sterol regulatory element binding protein (SREBP) isoforms. Here, we identify targets of SREBP-1 in mammalian liver using chromatin immunoprecipitation-high-throughput DNA sequencing. Antisera to SREBP-1 were used with liver chromatin from mice fed a high-carbohydrate diet after a fast, which leads to superinduction of hepatic SREBP-1c expression. SREBP-1-DNA complexes were subjected to massive parallel DNA sequencing using the Illumina Genome Analyzer II, resulting in 5.7 million sequence reads. Mapping these reads to the mouse reference genome identified 426 peaks of SREBP-1 binding vs. a control antibody. These binding peaks show a striking enrichment in proximal promoter regions, with 52% located within 1 kb upstream of a transcription start site. A previously undescribed sequence motif (5'-ACTACANNTCCC-3') was present in 76% of the total peaks, and we show that it is a functional SREBP-1 response element. Our analysis also reveals that an Sp1 consensus site is present as a "coregulatory" motif in 50% of the SREBP-1 binding peaks, consistent with previous functional studies. SREBP-1 bound not only to many well-characterized SREBP-1 target genes but to several other previously unknown targets in lipid and carbohydrate metabolism as well as many putative target genes in other diverse biological pathways.
Collapse
|
33
|
Abstract
Sterol regulatory element-binding proteins (SREBPs) have been established as physiological regulators of lipid synthesis. The molecular mechanisms by which cellular sterol balance and nutritional states regulate SREBP activities are the current research focus of this field. Meanwhile, it has been shown that overnutrition or disturbed energy balance causes accumulation of tissue lipids, leading to metabolic disorders, often referred to as 'lipotoxicity'. In this overview, I discuss the pathological aspects of SREBPs, which contribute to lipotoxicity in a wide variety of organs, including hepatic insulin resistance in hepatosteatosis, impaired insulin secretion in pancreatic beta-cells, diabetic nephropathy, cardiac arrythmiasis, and obesity.
Collapse
Affiliation(s)
- Hitoshi Shimano
- Department of Internal Medicine (Endocrinoglogy and Metabolism), Graduate School of Comprehensive Human Sciences, University of Tsukuba, Japan.
| |
Collapse
|
34
|
Iwasaki Y, Iwasaki H, Yatoh S, Ishikawa M, Kato T, Matsuzaka T, Nakagawa Y, Yahagi N, Kobayashi K, Takahashi A, Suzuki H, Yamada N, Shimano H. Nuclear SREBP-1a causes loss of pancreatic beta-cells and impaired insulin secretion. Biochem Biophys Res Commun 2008; 378:545-50. [PMID: 19056350 DOI: 10.1016/j.bbrc.2008.11.105] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Accepted: 11/17/2008] [Indexed: 10/21/2022]
Abstract
Transgenic mice expressing nuclear sterol regulatory element-binding protein-1a under the control of the insulin promoter were generated to determine the role of SREBP-1a in pancreatic beta-cells. Only low expressors could be established, which exhibited mild hyperglycemia, impaired glucose tolerance, and reduced plasma insulin levels compared to C57BL/6 controls. The islets isolated from the transgenic mice were fewer and smaller, and had decreased insulin content and unaltered glucagon staining. Both glucose- and potassium-stimulated insulin secretions were decreased. The transgenic islets consistently expressed genes for fatty acids and cholesterol synthesis, resulting in accumulation of triglycerides but not cholesterol. PDX-1, BetaEpsilonTauAlpha2, MafA, and IRS-2 were suppressed, partially explaining the loss and dysfunction of beta-cell mass. The transgenic mice on a high fat/high sucrose diet still exhibited impaired insulin secretion and continuous beta-cell growth defect. Therefore, nuclear SREBP-1a, even at a low level, strongly disrupts beta-cell mass and function.
Collapse
Affiliation(s)
- Yuko Iwasaki
- Department of Internal Medicine (Endocrinology and Metabolism), Graduate School of Comprehensive Human Sciences, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Porstmann T, Santos CR, Griffiths B, Cully M, Wu M, Leevers S, Griffiths JR, Chung YL, Schulze A. SREBP activity is regulated by mTORC1 and contributes to Akt-dependent cell growth. Cell Metab 2008; 8:224-36. [PMID: 18762023 PMCID: PMC2593919 DOI: 10.1016/j.cmet.2008.07.007] [Citation(s) in RCA: 1003] [Impact Index Per Article: 62.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2007] [Revised: 05/12/2008] [Accepted: 07/25/2008] [Indexed: 11/19/2022]
Abstract
Cell growth (accumulation of mass) needs to be coordinated with metabolic processes that are required for the synthesis of macromolecules. The PI3-kinase/Akt signaling pathway induces cell growth via activation of complex 1 of the target of rapamycin (TORC1). Here we show that Akt-dependent lipogenesis requires mTORC1 activity. Furthermore, nuclear accumulation of the mature form of the sterol responsive element binding protein (SREBP1) and expression of SREBP target genes was blocked by the mTORC1 inhibitor rapamycin. We also show that silencing of SREBP blocks Akt-dependent lipogenesis and attenuates the increase in cell size in response to Akt activation in vitro. Silencing of dSREBP in flies caused a reduction in cell and organ size and blocked the induction of cell growth by dPI3K. Our results suggest that the PI3K/Akt/TOR pathway regulates protein and lipid biosynthesis in an orchestrated manner and that both processes are required for cell growth.
Collapse
Affiliation(s)
- Thomas Porstmann
- Gene Expression Analysis Laboratory, 44 Lincoln's Inn Fields, London WC2A 3PX, UK
| | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Fernández-Álvarez A, Tur G, López-Rodas G, Casado M. Reciprocal regulation of the human sterol regulatory element binding protein (SREBP)-1a promoter by Sp1 and EGR-1 transcription factors. FEBS Lett 2007; 582:177-84. [DOI: 10.1016/j.febslet.2007.11.083] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2007] [Revised: 11/22/2007] [Accepted: 11/28/2007] [Indexed: 11/25/2022]
|