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Ma W, Cao M, Bi S, Du L, Chen J, Wang H, Jiang Y, Wu Y, Liao Y, Kong S, Liu J. MAX deficiency impairs human endometrial decidualization through down-regulating OSR2 in women with recurrent spontaneous abortion. Cell Tissue Res 2022; 388:453-469. [PMID: 35146559 PMCID: PMC9035420 DOI: 10.1007/s00441-022-03579-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 01/10/2022] [Indexed: 12/31/2022]
Abstract
Human uterine stromal cell undergoes decidualization for pregnancy establishment and maintenance, which involved extensive proliferation and differentiation. Increasing studies have suggested that recurrent spontaneous abortion (RSA) may result from defective endometrial stromal decidualization. However, the critical molecular mechanisms underlying impaired decidualization during RSA are still elusive. By using our recently published single-cell RNA sequencing (scRNA-seq) atlas, we found that MYC-associated factor X (MAX) was significantly downregulated in the stromal cells derived from decidual tissues of women with RSA, followed by verification with immunohistochemistry (IHC) and quantitative real-time polymerase chain reaction (qRT-PCR). MAX knockdown significantly impairs human endometrial stromal cells (HESCs) proliferation as determined by MTS assay and Ki67 immunostaining, and decidualization determined by F-actin, and decidualization markers. RNA-seq together with chromatin immunoprecipitation sequencing (ChIP-seq) and cleavage under targets and release using nuclease sequencing (CUT&RUN-seq) analysis were applied to explore the molecular mechanisms of MAX in regulation of decidualization, followed by dual-luciferase reporter assay to verify that MAX targets to (odd-skipped related transcription factor 2) OSR2 directly. Reduced expression of OSR2 was also confirmed in decidual tissues in women with RSA by IHC and qRT-PCR. OSR2 knockdown also significantly impairs HESCs decidualization. OSR2-overexpression could at least partly rescue the downregulated insulin-like growth factor binding protein 1 (IGFBP1) expression level in response to MAX knockdown. Collectively, MAX deficiency observed in RSA stromal cells not only attenuates HESCs proliferation but also impairs HESCs decidualization by downregulating OSR2 expression at transcriptional level directly.
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Affiliation(s)
- Weixu Ma
- Department of Obstetrics and Gynecology, Center for Reproductive Medicine, Key Laboratory for Major Obstetric Diseases of Guangdong Province, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Key Laboratory for Reproductive Medicine of Guangdong Province, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Mingzhu Cao
- Department of Obstetrics and Gynecology, Center for Reproductive Medicine, Key Laboratory for Major Obstetric Diseases of Guangdong Province, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Key Laboratory for Reproductive Medicine of Guangdong Province, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Shilei Bi
- Department of Obstetrics and Gynecology, Key Laboratory for Major Obstetric Diseases of Guangdong Province, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, Guangzhou, China
- Guangdong Engineering and Technology Research Center of Maternal-Fetal Medicine, Guangzhou, China
- Guangdong-Hong Kong-Macao Greater Bay Area Higher Education Joint Laboratory of Maternal-Fetal Medicine, Guangzhou, China
| | - Lili Du
- Department of Obstetrics and Gynecology, Key Laboratory for Major Obstetric Diseases of Guangdong Province, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, Guangzhou, China
- Guangdong Engineering and Technology Research Center of Maternal-Fetal Medicine, Guangzhou, China
- Guangdong-Hong Kong-Macao Greater Bay Area Higher Education Joint Laboratory of Maternal-Fetal Medicine, Guangzhou, China
| | - Jingsi Chen
- Department of Obstetrics and Gynecology, Key Laboratory for Major Obstetric Diseases of Guangdong Province, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, Guangzhou, China
- Guangdong Engineering and Technology Research Center of Maternal-Fetal Medicine, Guangzhou, China
- Guangdong-Hong Kong-Macao Greater Bay Area Higher Education Joint Laboratory of Maternal-Fetal Medicine, Guangzhou, China
| | - Haibin Wang
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of Xiamen University, Xiamen University, Xiamen, China
- Fujian Provincial Key Laboratory of Reproductive Health Research, School of Medicine, Xiamen University, Xiamen, China
| | - Yufei Jiang
- Xiamen Key Laboratory of Reproduction and Genetics, Department of Reproductive Medicine, Women and Children's Hospital, School of Medicine, Xiamen University, Xiamen, China
| | - Yixuan Wu
- Department of Obstetrics and Gynecology, Center for Reproductive Medicine, Key Laboratory for Major Obstetric Diseases of Guangdong Province, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Key Laboratory for Reproductive Medicine of Guangdong Province, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Yixin Liao
- Department of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Shuangbo Kong
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of Xiamen University, Xiamen University, Xiamen, China.
- Fujian Provincial Key Laboratory of Reproductive Health Research, School of Medicine, Xiamen University, Xiamen, China.
| | - Jianqiao Liu
- Department of Obstetrics and Gynecology, Center for Reproductive Medicine, Key Laboratory for Major Obstetric Diseases of Guangdong Province, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
- Key Laboratory for Reproductive Medicine of Guangdong Province, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
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MXD3 Promotes Obesity and the Androgen Receptor Signaling Pathway in Gender-Disparity Hepatocarcinogenesis. Cells 2021; 10:cells10123434. [PMID: 34943942 PMCID: PMC8700344 DOI: 10.3390/cells10123434] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 12/02/2021] [Accepted: 12/04/2021] [Indexed: 12/26/2022] Open
Abstract
Obesity is closely linked to metabolic diseases, particularly non-alcoholic steatohepatitis (NASH) or non-alcoholic fatty liver disease (NAFLD), ultimately leading to hepatocellular carcinoma (HCC). However, the molecular mechanisms of NASH-associated HCC (NAHCC) remain elusive. To explore the impact of Max dimerization protein 3 (MXD3), a transcription factor that regulates several cellular functions in disorders associated with metabolic diseases, we conditionally expressed Mxd3 proteins using Tet-on mxd3 transgenic zebrafish (MXs) with doxycycline (MXs + Dox) or without doxycycline (MXs − Dox) treatment. Overexpression of global MXD3 (gMX) or hepatic Mxd3 (hMX) was associated with obesity-related NAFLD pathophysiology in gMX + Dox, and liver fibrosis and HCC in hMX + Dox. Oil Red O (ORO)-stained signals were seen in intravascular blood vessels and liver buds of larval gMX + Dox, indicating that Mxd3 functionally promotes lipogenesis. The gMX + Dox-treated young adults exhibited an increase in body weight and visceral fat accumulation. The hMX + Dox-treated young adults showed normal body characteristics but exhibited liver steatosis and NASH-like phenotypes. Subsequently, steatohepatitis, liver fibrosis, and NAHCC were found in 6-month-old gMX + Dox adults compared with gMX − Dox adults at the same stage. Overexpression of Mxd3 also enhanced AR expression accompanied by the increase of AR-signaling pathways resulting in hepatocarcinogenesis in males. Our results demonstrate that global actions of Mxd3 are central to the initiation of obesity in the gMX zebrafish through their effects on adipogenesis and that MXD3 could serve as a therapeutic target for obesity-associated liver diseases.
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Björk C, Subramanian N, Liu J, Acosta JR, Tavira B, Eriksson AB, Arner P, Laurencikiene J. An RNAi Screening of Clinically Relevant Transcription Factors Regulating Human Adipogenesis and Adipocyte Metabolism. Endocrinology 2021; 162:6272286. [PMID: 33963396 PMCID: PMC8197287 DOI: 10.1210/endocr/bqab096] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Indexed: 12/13/2022]
Abstract
CONTEXT Healthy hyperplasic (many but smaller fat cells) white adipose tissue (WAT) expansion is mediated by recruitment, proliferation and/or differentiation of new fat cells. This process (adipogenesis) is controlled by transcriptional programs that have been mostly identified in rodents. OBJECTIVE A systemic investigation of adipogenic human transcription factors (TFs) that are relevant for metabolic conditions has not been revealed previously. METHODS TFs regulated in WAT by obesity, adipose morphology, cancer cachexia, and insulin resistance were selected from microarrays. Their role in differentiation of human adipose tissue-derived stem cells (hASC) was investigated by RNA interference (RNAi) screen. Lipid accumulation, cell number, and lipolysis were measured for all screened factors (148 TFs). RNA (RNAseq), protein (Western blot) expression, insulin, and catecholamine responsiveness were examined in hASC following siRNA treatment of selected target TFs. RESULTS Analysis of TFs regulated by metabolic conditions in human WAT revealed that many of them belong to adipogenesis-regulating pathways. The RNAi screen identified 39 genes that affected fat cell differentiation in vitro, where 11 genes were novel. Of the latter JARID2 stood out as being necessary for formation of healthy fat cell metabolic phenotype by regulating expression of multiple fat cell phenotype-specific genes. CONCLUSION This comprehensive RNAi screening in hASC suggests that a large proportion of WAT TFs that are impacted by metabolic conditions might be important for hyperplastic adipose tissue expansion. The screen also identified JARID2 as a novel TF essential for the development of functional adipocytes.
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Affiliation(s)
- Christel Björk
- Lipid laboratory, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, SE-14186, Sweden
| | - Narmadha Subramanian
- Lipid laboratory, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, SE-14186, Sweden
| | - Jianping Liu
- Karolinska High Throughput Center, Department of Medical Biochemistry and Biophysics (MBB), Division of Functional Genomics, Karolinska Institutet, Stockholm SE-171 77, Sweden
| | - Juan Ramon Acosta
- Lipid laboratory, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, SE-14186, Sweden
| | - Beatriz Tavira
- Lipid laboratory, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, SE-14186, Sweden
| | - Anders B Eriksson
- Karolinska High Throughput Center, Department of Medical Biochemistry and Biophysics (MBB), Division of Functional Genomics, Karolinska Institutet, Stockholm SE-171 77, Sweden
| | - Peter Arner
- Lipid laboratory, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, SE-14186, Sweden
| | - Jurga Laurencikiene
- Lipid laboratory, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, SE-14186, Sweden
- Correspondence: Jurga Laurencikiene, PhD, Karolinska Institutet, Lipid laboratory, Dept. of Medicine Huddinge (MedH), NEO, Hälsovägen 9/Blickagången 16, 14183 Huddinge, Sweden.
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Hatzmann FM, Ejaz A, Wiegers GJ, Mandl M, Brucker C, Lechner S, Rauchenwald T, Zwierzina M, Baumgarten S, Wagner S, Mattesich M, Waldegger P, Pierer G, Zwerschke W. Quiescence, Stemness and Adipogenic Differentiation Capacity in Human DLK1 -/CD34 +/CD24 + Adipose Stem/Progenitor Cells. Cells 2021; 10:cells10020214. [PMID: 33498986 PMCID: PMC7912596 DOI: 10.3390/cells10020214] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/13/2021] [Accepted: 01/16/2021] [Indexed: 12/26/2022] Open
Abstract
We explore the status of quiescence, stemness and adipogenic differentiation capacity in adipose stem/progenitor cells (ASCs) ex vivo, immediately after isolation from human subcutaneous white adipose tissue, by sorting the stromal vascular fraction into cell-surface DLK1+/CD34−, DLK1+/CD34dim and DLK1−/CD34+ cells. We demonstrate that DLK1−/CD34+ cells, the only population exhibiting proliferative and adipogenic capacity, express ex vivo the bonafide quiescence markers p21Cip1, p27Kip1 and p57Kip2 but neither proliferation markers nor the senescence marker p16Ink4a. The pluripotency markers NANOG, SOX2 and OCT4 are barely detectable in ex vivo ASCs while the somatic stemness factors, c-MYC and KLF4 and the early adipogenic factor C/EBPβ are highly expressed. Further sorting of ASCs into DLK1−/CD34+/CD24− and DLK1−/CD34+/CD24+ fractions shows that KLF4 and c-MYC are higher expressed in DLK1−/CD34+/CD24+ cells correlating with higher colony formation capacity and considerably lower adipogenic activity. Proliferation capacity is similar in both populations. Next, we show that ASCs routinely isolated by plastic-adherence are DLK1−/CD34+/CD24+. Intriguingly, CD24 knock-down in these cells reduces proliferation and adipogenesis. In conclusion, DLK1−/CD34+ ASCs in human sWAT exist in a quiescent state, express high levels of somatic stemness factors and the early adipogenic transcription factor C/EBPβ but senescence and pluripotency markers are barely detectable. Moreover, our data indicate that CD24 is necessary for adequate ASC proliferation and adipogenesis and that stemness is higher and adipogenic capacity lower in DLK1−/CD34+/CD24+ relative to DLK1−/CD34+/CD24− subpopulations.
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Affiliation(s)
- Florian M. Hatzmann
- Division of Cell Metabolism and Differentiation Research, Research Institute for Biomedical Aging Research, University of Innsbruck, Rennweg 10, A-6020 Innsbruck, Austria; (F.M.H.); (A.E.); (M.M.); (C.B.); (S.L.); (S.B.); (S.W.); (P.W.)
- Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80-82, A-6020 Innsbruck, Austria
| | - Asim Ejaz
- Division of Cell Metabolism and Differentiation Research, Research Institute for Biomedical Aging Research, University of Innsbruck, Rennweg 10, A-6020 Innsbruck, Austria; (F.M.H.); (A.E.); (M.M.); (C.B.); (S.L.); (S.B.); (S.W.); (P.W.)
- Department of Plastic Surgery, University of Pittsburgh Medical Center, 3550 Terrace Street, 6B Scaife Hall, Pittsburgh, PA 15261, USA
| | - G. Jan Wiegers
- Division of Developmental Immunology, Biocenter, Medical University of Innsbruck, Innrain 80-82, A-6020 Innsbruck, Austria;
| | - Markus Mandl
- Division of Cell Metabolism and Differentiation Research, Research Institute for Biomedical Aging Research, University of Innsbruck, Rennweg 10, A-6020 Innsbruck, Austria; (F.M.H.); (A.E.); (M.M.); (C.B.); (S.L.); (S.B.); (S.W.); (P.W.)
- Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80-82, A-6020 Innsbruck, Austria
| | - Camille Brucker
- Division of Cell Metabolism and Differentiation Research, Research Institute for Biomedical Aging Research, University of Innsbruck, Rennweg 10, A-6020 Innsbruck, Austria; (F.M.H.); (A.E.); (M.M.); (C.B.); (S.L.); (S.B.); (S.W.); (P.W.)
- Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80-82, A-6020 Innsbruck, Austria
| | - Stefan Lechner
- Division of Cell Metabolism and Differentiation Research, Research Institute for Biomedical Aging Research, University of Innsbruck, Rennweg 10, A-6020 Innsbruck, Austria; (F.M.H.); (A.E.); (M.M.); (C.B.); (S.L.); (S.B.); (S.W.); (P.W.)
| | - Tina Rauchenwald
- Department of Plastic, Reconstructive and Aesthetic Surgery, Medical University of Innsbruck, Anichstraße 35, A-6020 Innsbruck, Austria; (T.R.); (M.Z.); (M.M.); (G.P.)
| | - Marit Zwierzina
- Department of Plastic, Reconstructive and Aesthetic Surgery, Medical University of Innsbruck, Anichstraße 35, A-6020 Innsbruck, Austria; (T.R.); (M.Z.); (M.M.); (G.P.)
| | - Saphira Baumgarten
- Division of Cell Metabolism and Differentiation Research, Research Institute for Biomedical Aging Research, University of Innsbruck, Rennweg 10, A-6020 Innsbruck, Austria; (F.M.H.); (A.E.); (M.M.); (C.B.); (S.L.); (S.B.); (S.W.); (P.W.)
| | - Sonja Wagner
- Division of Cell Metabolism and Differentiation Research, Research Institute for Biomedical Aging Research, University of Innsbruck, Rennweg 10, A-6020 Innsbruck, Austria; (F.M.H.); (A.E.); (M.M.); (C.B.); (S.L.); (S.B.); (S.W.); (P.W.)
| | - Monika Mattesich
- Department of Plastic, Reconstructive and Aesthetic Surgery, Medical University of Innsbruck, Anichstraße 35, A-6020 Innsbruck, Austria; (T.R.); (M.Z.); (M.M.); (G.P.)
| | - Petra Waldegger
- Division of Cell Metabolism and Differentiation Research, Research Institute for Biomedical Aging Research, University of Innsbruck, Rennweg 10, A-6020 Innsbruck, Austria; (F.M.H.); (A.E.); (M.M.); (C.B.); (S.L.); (S.B.); (S.W.); (P.W.)
- Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80-82, A-6020 Innsbruck, Austria
| | - Gerhard Pierer
- Department of Plastic, Reconstructive and Aesthetic Surgery, Medical University of Innsbruck, Anichstraße 35, A-6020 Innsbruck, Austria; (T.R.); (M.Z.); (M.M.); (G.P.)
| | - Werner Zwerschke
- Division of Cell Metabolism and Differentiation Research, Research Institute for Biomedical Aging Research, University of Innsbruck, Rennweg 10, A-6020 Innsbruck, Austria; (F.M.H.); (A.E.); (M.M.); (C.B.); (S.L.); (S.B.); (S.W.); (P.W.)
- Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80-82, A-6020 Innsbruck, Austria
- Correspondence: ; Tel.: +43-512-507508-32; Fax: +43-512-507508-99
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Li Y, Schwalie PC, Bast-Habersbrunner A, Mocek S, Russeil J, Fromme T, Deplancke B, Klingenspor M. Systems-Genetics-Based Inference of a Core Regulatory Network Underlying White Fat Browning. Cell Rep 2020; 29:4099-4113.e5. [PMID: 31851936 DOI: 10.1016/j.celrep.2019.11.053] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 10/02/2019] [Accepted: 11/13/2019] [Indexed: 02/06/2023] Open
Abstract
Recruitment of brite/beige cells, known as browning of white adipose tissue (WAT), is an efficient way to turn an energy-storing organ into an energy-dissipating one and may therefore be of therapeutic value in combating obesity. However, a comprehensive understanding of the regulatory mechanisms mediating WAT browning is still lacking. Here, we exploit the large natural variation in WAT browning propensity between inbred mouse strains to gain an inclusive view of the core regulatory network coordinating this cellular process. Combining comparative transcriptomics, perturbation-based validations, and gene network analyses, we present a comprehensive gene regulatory network of inguinal WAT browning, revealing up to four distinct regulatory modules with key roles for uncovered transcriptional factors, while also providing deep insights into the genetic architecture of brite adipogenesis. The presented findings therefore greatly increase our understanding of the molecular drivers mediating the intriguing cellular heterogeneity and plasticity of adipose tissue.
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Affiliation(s)
- Yongguo Li
- Chair for Molecular Nutritional Medicine, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Gregor-Mendel-Str. 2, 85354 Freising, Germany; EKFZ-Else Kröner-Fresenius Center for Nutritional Medicine, Technical University of Munich, Gregor-Mendel-Str. 2, 85354 Freising, Germany
| | - Petra C Schwalie
- Institute of Bio-engineering, School of Life Sciences, EPFL and Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Andrea Bast-Habersbrunner
- Chair for Molecular Nutritional Medicine, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Gregor-Mendel-Str. 2, 85354 Freising, Germany; EKFZ-Else Kröner-Fresenius Center for Nutritional Medicine, Technical University of Munich, Gregor-Mendel-Str. 2, 85354 Freising, Germany
| | - Sabine Mocek
- Chair for Molecular Nutritional Medicine, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Gregor-Mendel-Str. 2, 85354 Freising, Germany; EKFZ-Else Kröner-Fresenius Center for Nutritional Medicine, Technical University of Munich, Gregor-Mendel-Str. 2, 85354 Freising, Germany
| | - Julie Russeil
- Institute of Bio-engineering, School of Life Sciences, EPFL and Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Tobias Fromme
- Chair for Molecular Nutritional Medicine, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Gregor-Mendel-Str. 2, 85354 Freising, Germany; EKFZ-Else Kröner-Fresenius Center for Nutritional Medicine, Technical University of Munich, Gregor-Mendel-Str. 2, 85354 Freising, Germany
| | - Bart Deplancke
- Institute of Bio-engineering, School of Life Sciences, EPFL and Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland.
| | - Martin Klingenspor
- Chair for Molecular Nutritional Medicine, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Gregor-Mendel-Str. 2, 85354 Freising, Germany; EKFZ-Else Kröner-Fresenius Center for Nutritional Medicine, Technical University of Munich, Gregor-Mendel-Str. 2, 85354 Freising, Germany.
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Gomez-Cambronero J. Lack of effective translational regulation of PLD expression and exosome biogenesis in triple-negative breast cancer cells. Cancer Metastasis Rev 2019; 37:491-507. [PMID: 30091053 DOI: 10.1007/s10555-018-9753-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer that is difficult to treat since cells lack the three receptors (ES, PR, or HER) that the most effective treatments target. We have used a well-established TNBC cell line (MDA-MB-231) from which we found evidence in support for a phospholipase D (PLD)-mediated tumor growth and metastasis: high levels of expression of PLD, as well as the absence of inhibitory miRs (such as miR-203) and 3'-mRNA PARN deadenylase activity in these cells. Such findings are not present in a luminal B cell line, MCF-7, and we propose a new miR•PARN•PLD node that is not uniform across breast cancer molecular subtypes and as such TNBC could be pharmacologically targeted differentially. We review the participation of PLD and phosphatidic acid (PA), its enzymatic product, as new "players" in breast cancer biology, with the aspects of regulation of the tumor microenvironment, macrophage polarization, regulation of PLD transcripts by specific miRs and deadenylases, and PLD-regulated exosome biogenesis. A new signaling miR•PARN•PLD node could serve as new biomarkers for TNBC abnormal signaling and metastatic disease staging, potentially before metastases are able to be visualized using conventional imaging.
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Affiliation(s)
- Julian Gomez-Cambronero
- Department of Biochemistry and Molecular Biology, Wright State University School of Medicine, 3640 Colonel Glenn Highway, Dayton, OH, 45435, USA.
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7
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Li S, Xue T, He F, Liu Z, Ouyang S, Cao D, Wu J. A time-resolved proteomic analysis of transcription factors regulating adipogenesis of human adipose derived stem cells. Biochem Biophys Res Commun 2019; 511:855-861. [PMID: 30850164 DOI: 10.1016/j.bbrc.2019.02.134] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 02/25/2019] [Indexed: 12/30/2022]
Abstract
Adipogenesis is one of the key processes during obesity development. Better understanding of this process could advance our knowledge on obesity and its treatment. Transcription factors (TFs) are master regulators during adipogenesis, however, a system-wide analysis of TFs dynamic proteome during adipogenesis is lacking. Here, we profiled 472 TFs and systematically elucidated their roles during the first 7 days of adipogenesis of human adipose-derived stem cells (hADSCs) on proteome scale. We identified two main and four sub-phases during adipogenesis. The commitment phase (0 h-8 h) mainly mediated stem cell proliferation, differentiation and chromatin remodeling, in which proteins of SWI/SNF family are the key centroid nodes. The determination phase (1D-7D) predominately regulated fat cell differentiation and response to lipid and oxygen, which could be associated with terminal differentiation of adipocyte and responsible for maturation. PPARγ, CREB1 and MYC are the centroid nodes of this phase. Remarkably, we identified and verified three TFs (BATF3, MAFF and MXD4) as novel regulators of adipogenesis, whose over-expression could inhibit adipogenesis of hADSCs in vitro. Overall, our study provided a valuable TFs resource to understand the complex process of adipogenesis.
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Affiliation(s)
- Sen Li
- Department of Biochemistry & Immunology, Capital Institute of Pediatrics-Peking University Teaching Hospital, NO. 2, Yabao Road, Chaoyang District, Beijing, 100020, China.
| | - Ting Xue
- Omicsolution Co, Ltd, Shanghai, 201101, China.
| | - Feng He
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, NO. 2, Yabao Road, Chaoyang District, Beijing, 100020, China.
| | - Zhuo Liu
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, NO. 2, Yabao Road, Chaoyang District, Beijing, 100020, China.
| | - Shengrong Ouyang
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, NO. 2, Yabao Road, Chaoyang District, Beijing, 100020, China.
| | - Dingding Cao
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, NO. 2, Yabao Road, Chaoyang District, Beijing, 100020, China.
| | - Jianxin Wu
- Department of Biochemistry & Immunology, Capital Institute of Pediatrics-Peking University Teaching Hospital, NO. 2, Yabao Road, Chaoyang District, Beijing, 100020, China; Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, NO. 2, Yabao Road, Chaoyang District, Beijing, 100020, China.
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8
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Marquez MP, Alencastro F, Madrigal A, Jimenez JL, Blanco G, Gureghian A, Keagy L, Lee C, Liu R, Tan L, Deignan K, Armstrong B, Zhao Y. The Role of Cellular Proliferation in Adipogenic Differentiation of Human Adipose Tissue-Derived Mesenchymal Stem Cells. Stem Cells Dev 2017; 26:1578-1595. [PMID: 28874101 DOI: 10.1089/scd.2017.0071] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Mitotic clonal expansion has been suggested as a prerequisite for adipogenesis in murine preadipocytes, but the precise role of cell proliferation during human adipogenesis is unclear. Using adipose tissue-derived human mesenchymal stem cells as an in vitro cell model for adipogenic study, a group of cell cycle regulators, including Cdk1 and CCND1, were found to be downregulated as early as 24 h after adipogenic initiation and consistently, cell proliferation activity was restricted to the first 48 h of adipogenic induction. Cell proliferation was either further inhibited using siRNAs targeting cell cycle genes or enhanced by supplementing exogenous growth factor, basic fibroblast growth factor (bFGF), at specific time intervals during adipogenesis. Expression knockdown of Cdk1 at the initiation of adipogenic induction resulted in significantly increased adipocytes, even though total number of cells was significantly reduced compared to siControl-treated cells. bFGF stimulated proliferation throughout adipogenic differentiation, but exerted differential effect on adipogenic outcome at different phases, promoting adipogenesis during mitotic phase (first 48 h), but significantly inhibiting adipogenesis during adipogenic commitment phase (days 3-6). Our results demonstrate that cellular proliferation is counteractive to adipogenic commitment in human adipogenesis. However, cellular proliferation stimulation can be beneficial for adipogenesis during the mitotic phase by increasing the population of cells capable of committing to adipocytes before adipogenic commitment.
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Affiliation(s)
- Maribel P Marquez
- 1 Biological Sciences Department, California State Polytechnic University at Pomona , Pomona, California
| | - Frances Alencastro
- 1 Biological Sciences Department, California State Polytechnic University at Pomona , Pomona, California
| | - Alma Madrigal
- 1 Biological Sciences Department, California State Polytechnic University at Pomona , Pomona, California
| | - Jossue Loya Jimenez
- 1 Biological Sciences Department, California State Polytechnic University at Pomona , Pomona, California
| | - Giselle Blanco
- 1 Biological Sciences Department, California State Polytechnic University at Pomona , Pomona, California
| | - Alex Gureghian
- 1 Biological Sciences Department, California State Polytechnic University at Pomona , Pomona, California
| | - Laura Keagy
- 1 Biological Sciences Department, California State Polytechnic University at Pomona , Pomona, California
| | - Cecilia Lee
- 1 Biological Sciences Department, California State Polytechnic University at Pomona , Pomona, California
| | - Robert Liu
- 1 Biological Sciences Department, California State Polytechnic University at Pomona , Pomona, California
| | - Lun Tan
- 1 Biological Sciences Department, California State Polytechnic University at Pomona , Pomona, California
| | - Kristen Deignan
- 1 Biological Sciences Department, California State Polytechnic University at Pomona , Pomona, California
| | | | - Yuanxiang Zhao
- 1 Biological Sciences Department, California State Polytechnic University at Pomona , Pomona, California
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9
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Kim D, Hong A, Park HI, Shin WH, Yoo L, Jeon SJ, Chung KC. Deubiquitinating enzyme USP22 positively regulates c-Myc stability and tumorigenic activity in mammalian and breast cancer cells. J Cell Physiol 2017; 232:3664-3676. [PMID: 28160502 DOI: 10.1002/jcp.25841] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 02/03/2017] [Accepted: 02/03/2017] [Indexed: 12/22/2022]
Abstract
The proto-oncogene c-Myc has a pivotal function in growth control, differentiation, and apoptosis and is frequently affected in human cancer, including breast cancer. Ubiquitin-specific protease 22 (USP22), a member of the USP family of deubiquitinating enzymes (DUBs), mediates deubiquitination of target proteins, including histone H2B and H2A, telomeric repeat binding factor 1, and cyclin B1. USP22 is also a component of the mammalian SAGA transcriptional co-activating complex. In this study, we explored the functional role of USP22 in modulating c-Myc stability and its physiological relevance in breast cancer progression. We found that USP22 promotes deubiquitination of c-Myc in several breast cancer cell lines, resulting in increased levels of c-Myc. Consistent with this, USP22 knockdown reduces c-Myc levels. Furthermore, overexpression of USP22 stimulates breast cancer cell growth and colony formation, and increases c-Myc tumorigenic activity. In conclusion, the present study reveals that USP22 in breast cancer cell lines increases c-Myc stability through c-Myc deubiquitination, which is closely correlated with breast cancer progression.
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Affiliation(s)
- Dongyeon Kim
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Ahyoung Hong
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Hye In Park
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Woo Hyun Shin
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Lang Yoo
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Seo Jeong Jeon
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Kwang Chul Chung
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
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10
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Cardiac mesenchymal progenitors differentiate into adipocytes via Klf4 and c-Myc. Cell Death Dis 2016; 7:e2190. [PMID: 27077806 PMCID: PMC4855651 DOI: 10.1038/cddis.2016.31] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 01/19/2016] [Accepted: 01/20/2016] [Indexed: 12/20/2022]
Abstract
Direct reprogramming of differentiated cells to pluripotent stem cells has great potential to improve our understanding of developmental biology and disorders such as cancers, and has implications for regenerative medicine. In general, the effects of transcription factors (TFs) that are transduced into cells can be influenced by pre-existing transcriptional networks and epigenetic modifications. However, previous work has identified four key TFs, Oct4, Sox2, Klf4 and c-Myc, which can reprogram various differentiated cells to generate induced pluripotent stem cells. Here, we show that in the heart, the transduction of cardiac mesenchymal progenitors (CMPs) with Klf4 and c-Myc (KM) was sufficient to drive the differentiation of these cells into adipocytes without the use of adipogenic stimulation cocktail, that is, insulin, 3-isobutyl-1-methylxanthine (IBMX) and dexamethasone. KM-transduced CMPs exhibited a gradually increased expression of adipogenic-related genes, such as C/Ebpα, Pparγ and Fabp4, activation of the peroxisome proliferator-activated receptor (PPAR) signaling pathway, inactivation of the cell cycle-related pathway and formation of cytoplasmic lipid droplets within 10 days. In contrast, NIH3T3 fibroblasts, 3T3-L1 preadipocytes, and bone marrow-derived mesenchymal stem cells transduced with KM did not differentiate into adipocytes. Both in vitro and in vivo cardiac ischemia reperfusion injury models demonstrated that the expression of KM genes sharply increased following a reperfusion insult. These results suggest that ectopic adipose tissue formation in the heart following myocardial infarction results from CMPs that express KM following a stress response.
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11
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XIE YUXIN, XIE KEQI, GOU QIHENG, CHEN NIANYONG. IκB kinase α functions as a tumor suppressor in epithelial-derived tumors through an NF-κB-independent pathway (Review). Oncol Rep 2015; 34:2225-32. [DOI: 10.3892/or.2015.4229] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 07/06/2015] [Indexed: 11/06/2022] Open
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12
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Reverse engineering the neuroblastoma regulatory network uncovers MAX as one of the master regulators of tumor progression. PLoS One 2013; 8:e82457. [PMID: 24349289 PMCID: PMC3857773 DOI: 10.1371/journal.pone.0082457] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 10/23/2013] [Indexed: 12/17/2022] Open
Abstract
Neuroblastoma is the most common extracranial tumor and a major cause of infant cancer mortality worldwide. Despite its importance, little is known about its molecular mechanisms. A striking feature of this tumor is its clinical heterogeneity. Possible outcomes range from aggressive invasion to other tissues, causing patient death, to spontaneous disease regression or differentiation into benign ganglioneuromas. Several efforts have been made in order to find tumor progression markers. In this work, we have reconstructed the neuroblastoma regulatory network using an information-theoretic approach in order to find genes involved in tumor progression and that could be used as outcome predictors or as therapeutic targets. We have queried the reconstructed neuroblastoma regulatory network using an aggressive neuroblastoma metastasis gene signature in order to find its master regulators (MRs). MRs expression profiles were then investigated in other neuroblastoma datasets so as to detect possible clinical significance. Our analysis pointed MAX as one of the MRs of neuroblastoma progression. We have found that higher MAX expression correlated with favorable patient outcomes. We have also found that MAX expression and protein levels were increased during neuroblastoma SH-SY5Y cells differentiation. We propose that MAX is involved in neuroblastoma progression, possibly increasing cell differentiation by means of regulating the availability of MYC:MAX heterodimers. This mechanism is consistent with the results found in our SH-SY5Y differentiation protocol, suggesting that MAX has a more central role in these cells differentiation than previously reported. Overexpression of MAX has been identified as anti-tumorigenic in other works, but, to our knowledge, this is the first time that the link between the expression of this gene and malignancy was verified under physiological conditions.
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13
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Shimada Y, Kuroyanagi J, Zhang B, Ariyoshi M, Umemoto N, Nishimura Y, Tanaka T. Downregulation of Max dimerization protein 3 is involved in decreased visceral adipose tissue by inhibiting adipocyte differentiation in zebrafish and mice. Int J Obes (Lond) 2013; 38:1053-60. [PMID: 24254064 DOI: 10.1038/ijo.2013.217] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 10/16/2013] [Accepted: 11/05/2013] [Indexed: 01/14/2023]
Abstract
BACKGROUND The diet-induced obesity model of zebrafish (DIO-zebrafish) share a common pathophysiological pathway with mammalian obesity. OBJECTIVES We aimed to investigate the role of Max dimerization protein 3 (MXD3) in visceral fat accumulation and adipocyte differentiation, by conducting knockdown experiments using zebrafish and mouse preadipocytes. METHODS To identify genes related to visceral adiposity, we conducted transcriptome analyses of human and zebrafish obese populations using the Gene Expression Omnibus and DNA microarray. We then intraperitoneally injected morpholino antisense oligonucleotides (MO-mxd3) to knockdown mxd3 gene expression in DIO-zebrafish and measured several parameters, which reflected human obesity and associated metabolic diseases. Finally, lentiviral Mxd3 shRNA knockdown in mouse 3T3-L1 preadipocytes was conducted. Quantitative PCR analyses of several differentiation markers were conducted during these gene knockdown experiments. RESULTS We found that MXD3 expression was increased in the obese population in humans and zebrafish. Intraperitoneal MO-mxd3 administration to DIO-zebrafish suppressed the increase in body weight, visceral fat accumulation and the size of mature adipocytes. Subsequently, dyslipidemia and liver steatosis were also ameliorated by MO-mxd3. In mouse adipocytes, Mxd3 expression was drastically increased in the early differentiation stage. Mxd3 shRNA inhibited preadipocyte proliferation and adipocyte maturation. Quantitative PCR analyses showed that the early differentiation marker, CCAAT/enhancer-binding protein delta (Cebpd) and late differentiation markers (CCAAT/enhancer-binding protein, alpha and peroxisome proliferator-activated receptor gamma) were downregulated by Mxd3 knockdown in 3T3-L1 cells and DIO-zebrafish. Subsequently, mature adipocyte markers (adiponectin and caveolin 1 for zebrafish, and fatty acid binding protein 4 and stearoyl-coenzyme A desaturase 1 for mouse adipocytes) were also decreased. CONCLUSION Mxd3 regulates preadipocyte proliferation and early adipocyte differentiation via Cebpd downregulation in vitro and in vivo. Integrated analysis of human and zebrafish transcriptomes allows identification of a novel therapeutic target against human obesity and further associated metabolic disease.
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Affiliation(s)
- Y Shimada
- 1] Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics, Mie University Graduate School of Medicine, Mie, Japan [2] Department of Systems Pharmacology, Mie University Graduate School of Medicine, Mie, Japan [3] Mie University Medical Zebrafish Research Center, Mie, Japan [4] Department of Bioinformatics, Mie University Life Science Research Center, Mie, Japan [5] Department of Omics Medicine, Mie University Industrial Technology Innovation, Mie, Japan
| | - J Kuroyanagi
- Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics, Mie University Graduate School of Medicine, Mie, Japan
| | - B Zhang
- Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics, Mie University Graduate School of Medicine, Mie, Japan
| | - M Ariyoshi
- 1] Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics, Mie University Graduate School of Medicine, Mie, Japan [2] Department of Systems Pharmacology, Mie University Graduate School of Medicine, Mie, Japan
| | - N Umemoto
- 1] Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics, Mie University Graduate School of Medicine, Mie, Japan [2] Department of Systems Pharmacology, Mie University Graduate School of Medicine, Mie, Japan
| | - Y Nishimura
- 1] Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics, Mie University Graduate School of Medicine, Mie, Japan [2] Department of Systems Pharmacology, Mie University Graduate School of Medicine, Mie, Japan [3] Mie University Medical Zebrafish Research Center, Mie, Japan [4] Department of Bioinformatics, Mie University Life Science Research Center, Mie, Japan [5] Department of Omics Medicine, Mie University Industrial Technology Innovation, Mie, Japan
| | - T Tanaka
- 1] Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics, Mie University Graduate School of Medicine, Mie, Japan [2] Department of Systems Pharmacology, Mie University Graduate School of Medicine, Mie, Japan [3] Mie University Medical Zebrafish Research Center, Mie, Japan [4] Department of Bioinformatics, Mie University Life Science Research Center, Mie, Japan [5] Department of Omics Medicine, Mie University Industrial Technology Innovation, Mie, Japan
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14
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Park E, Liu B, Xia X, Zhu F, Jami WB, Hu Y. Role of IKKα in skin squamous cell carcinomas. Future Oncol 2011; 7:123-34. [PMID: 21174543 DOI: 10.2217/fon.10.166] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) are two major types of skin cancer derived from keratinocytes. SCC is a more aggressive type of cancer than BCC in humans. One significant difference between SCC and BCC is that SCC development is generally associated with cell dedifferentiation and morphological changes. When SCC is converted to spindle cell carcinoma, the latest stage of cancer, the tumor cells change to a fibroblastic cell morphology (epithelial-to-mesenchymal transition) and lose their differentiation markers. Recently, several laboratories have reported altered IκB kinase α (IKKα) protein localization, downregulated IKKα, and IKKα gene deletions and mutations in human SCCs of the skin, lung, esophagus, and neck and head. In addition, IKKα reduction promotes chemical carcinogen- and ultraviolet B-induced skin carcinogenesis, and IKKα deletion in keratinocytes causes spontaneous skin SCCs, but not BCCs, in mice. Thus, IKKα emerges as a bona fide skin tumor suppressor. In this article, we will discuss the role of IKKα in skin SCC development.
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Affiliation(s)
- Eunmi Park
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA
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15
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Boros K, Lacaud G, Kouskoff V. The transcription factor Mxd4 controls the proliferation of the first blood precursors at the onset of hematopoietic development in vitro. Exp Hematol 2011; 39:1090-100. [PMID: 21782766 DOI: 10.1016/j.exphem.2011.07.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Revised: 07/11/2011] [Accepted: 07/14/2011] [Indexed: 11/20/2022]
Abstract
OBJECTIVE The balance between proliferation and differentiation during hematopoietic development in the embryo is a complex process, the detailed molecular mechanisms of which remain to be fully characterized. The transcription factor Mxd4, a member of the Myc-Max-Mad network, was identified in a global gene expression profiling screen as being tightly regulated at the onset of hematopoietic lineage specification upon in vitro differentiation of mouse embryonic stem cells. Our study investigated the Mxd4 expression pattern at the onset of hematopoiesis and the biological relevance of its sharp and transient downregulation. MATERIALS AND METHODS To study the expression pattern and role of Mxd4 at the onset of hematopoiesis, the in vitro differentiation of embryonic stem cells was used as a model system. Gain of function assays were performed using a doxycycline-inducible embryonic stem cell system. RESULTS We show here that Mxd4 expression is transiently downregulated at an early stage of commitment to the hematopoietic lineage. Enforced expression of Mxd4 at this period of differentiation results in a defect in hematopoietic progenitor development, with impaired development of both primitive and definitive blood lineages. This effect is due to a severe decrease in cell proliferation, with an increased frequency of cells in the G(0)/G(1) phase of the cell cycle, alongside a reduced frequency of cells in the S phase. CONCLUSIONS Together our results indicate that during embryonic hematopoietic differentiation Mxd4 is an important player in the regulation of blood progenitor proliferation, and suggest that downregulation of its expression might be required for a proliferative burst preceding lineage specification.
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Affiliation(s)
- Katalin Boros
- Cancer Research UK Stem Cell Hematopoiesis Group, Paterson Institute for Cancer Research, University of Manchester, UK
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16
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Lüscher B. MAD1 and its life as a MYC antagonist: an update. Eur J Cell Biol 2011; 91:506-14. [PMID: 21917351 DOI: 10.1016/j.ejcb.2011.07.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2011] [Revised: 07/21/2011] [Accepted: 07/25/2011] [Indexed: 12/16/2022] Open
Abstract
The MYC/MAX/MAD network is of central importance for controlling cell physiology. The network is compiled of transcriptional regulators that form different heterodimers, which can either activate or repress the expression of target genes. Thus these proteins function as a molecular switch to control gene expression. MAD1, a member of this network, acts as a transcriptional repressor. It interacts with MAX to form the OFF position of the switch, antagonizing MYC/MAX complexes that define the ON position. MAD1 regulates cell proliferation and apoptosis through a number of target genes. In addition recent evidence indicates that the expression and activity of MAD1 are regulated at multiple levels. Here the recent developments are summarized, in comparison to MYC, of our understanding how the expression of the MAD1 gene and protein are controlled and what the functional consequences and downstream effectors of MAD1 are, which relay its activity as a transcriptional regulator.
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Affiliation(s)
- Bernhard Lüscher
- Institute of Biochemistry and Molecular Biology, Medical School, RWTH Aachen University, 52057 Aachen, Germany.
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17
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Hein N, Jiang K, Cornelissen C, Lüscher B. TGFβ1 enhances MAD1 expression and stimulates promoter-bound Pol II phosphorylation: basic functions of C/EBP, SP and SMAD3 transcription factors. BMC Mol Biol 2011; 12:9. [PMID: 21345218 PMCID: PMC3056803 DOI: 10.1186/1471-2199-12-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Accepted: 02/23/2011] [Indexed: 12/28/2022] Open
Abstract
Background The MAD1 protein, a member of the MYC/MAX/MAD network of transcriptional regulators, controls cell proliferation, differentiation and apoptosis. MAD1 functions as a transcriptional repressor, one direct target gene being the tumor suppressor PTEN. Repression of this gene is critical to mediate the anti-apoptotic function of MAD1. Under certain conditions it also antagonizes the functions of the oncoprotein MYC. Previous studies have demonstrated that MAD1 expression is controlled by different cytokines and growth factors. Moreover we have recently demonstrated that the MAD1 promoter is controlled by the cytokine granulocyte colony-stimulating factor (G-CSF) through the activation of STAT3, MAP kinases and C/EBP transcription factors. Results We observed that in addition to G-CSF, the cytokine transforming growth factor β (TGFβ1) rapidly induced the expression of MAD1 mRNA and protein in promyelocytic tumor cells. Moreover we found that C/EBP and SP transcription factors cooperated in regulating the expression of MAD1. This cooperativity was dependent on the respective binding sites in the proximal promoter, with the CCAAT boxes being bound by C/EBPα/β heterodimers. Both C/EBP and SP transcription factors bound constitutively to DNA without obvious changes in response to TGFβ1. In addition SMAD3 stimulated the MAD1 reporter, cooperated with C/EBPα and was bound to the core promoter region. Thus SMAD3 appears to be a potential link between TGFβ1 signaling and C/EBP regulated promoter activity. Moreover TGFβ1 stimulated the phosphorylation of polymerase II at serine 2 and its progression into the gene body, consistent with enhanced processivity. Conclusions Our findings suggest that C/EBP and SP factors provide a platform of transcription factors near the core promoter of the MAD1 gene that participate in mediating signal transduction events emanating from different cytokine receptors. SMAD3, a target of TGFβ1 signaling, appears to be functionally relevant. We suggest that a key event induced by TGFβ1 at the MAD1 promoter is the recruitment or activation of cofactors, possibly in complex with C/EBP, SP, and SMAD3 transcriptional regulators, that control polymerase activity.
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Affiliation(s)
- Nadine Hein
- Institute of Biochemistry and Molecular Biology, Medical School, RWTH Aachen University, 52057 Aachen, Germany
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18
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Abstract
Myc is the most frequently deregulated oncogene in human tumors. The protein belongs to the Myc/Max/Mxd network of transcriptional regulators important for cell growth, proliferation, differentiation, and apoptosis. The ratio between Mnt/Max and c-Myc/Max on the 5'-CACGTG-3' E-box sequence at shared target genes is of great importance for cell cycle progression and arrest. Serum stimulation of quiescent cells results in phosphorylation of Mnt and disruption of the critical Mnt-mSin3-HDAC1 interaction. This in turn leads to increased expression of the Myc/Mnt target gene cyclin D2. It is therefore possible that Myc function relies on its ability to overcome transcriptional repression by Mnt and that relief of Mnt-mediated transcriptional repression is of greater importance for regulation of target genes than the sole activation by Myc. In addition, Mnt has many features of a tumor suppressor and may thus be nonfunctional or inactivated in human tumors. In summary, accumulating evidence supports the model of Mnt as the key regulator of the network in vivo.
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Affiliation(s)
- Therese Wahlström
- Department of Microbiology, Tumor, and Cell Biology (MTC), Karolinska Institutet, SE-171 77 Stockholm, Sweden
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19
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Farfsing A, Engel F, Seiffert M, Hartmann E, Ott G, Rosenwald A, Stilgenbauer S, Döhner H, Boutros M, Lichter P, Pscherer A. Gene knockdown studies revealed CCDC50 as a candidate gene in mantle cell lymphoma and chronic lymphocytic leukemia. Leukemia 2009; 23:2018-26. [PMID: 19641524 DOI: 10.1038/leu.2009.144] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The two B-cell non-Hodgkin's lymphoma entities, chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL), show recurrent chromosomal gains of 3q25-q29, 12q13-q14 and 18q21-q22. The pathomechanisms affected by these aberrations are not understood. The aim of this study was to identify genes, located within these gained regions, which control cell death and cell survival of MCL and CLL cancer cells. Blood samples collected from 18 patients with CLL and 6 patients with MCL, as well as 6 cell lines representing both malignancies were analyzed by gene expression profiling. By a comparison of genomic DNA and gene expression, 72 candidate genes were identified. We performed a limited RNA interference screening with these candidates to identify genes affecting cell survival. CCDC50 (coiled coil domain containing protein 50), SERPINI2 and SMARCC2 mediated a reduction of cell viability in primary CLL cells as well as in cell lines. Gene knockdown and a nuclear factor kappa B (NFkappaB) reporter gene assay revealed that CCDC50 is required for survival in MCL and CLL cells and controls NFkappaB signaling.
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Affiliation(s)
- A Farfsing
- Division of Molecular Genetics, German Cancer Research Center (DKFZ), Heidelberg, Germany
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Kawamura K, Tachibana M, Sunanaga T. Cell proliferation dynamics of somatic and germline tissues during zooidal life span in the colonial tunicate Botryllus primigenus. Dev Dyn 2008; 237:1812-25. [PMID: 18570248 DOI: 10.1002/dvdy.21592] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Botryllus primigenus is a colonial tunicate in which three successive generations develop synchronously. To identify proliferation centers and possible adult stem cells during asexual reproduction, somatic and germline cells were labeled with 5-bromo-2'-deoxyuridine (BrdU). In the youngest generation, multipotent epithelial cells exhibited an average labeling index (LI) of 30% 24 hr after BrdU injection. In the middle generation, the LI of organ rudiments decreased gradually and reached zero by the beginning of the eldest generation. Exceptionally, cells of specialized tissues such as the pharyngeal inner longitudinal vessel and the posterior end of the endostyle continued DNA synthesis and mitosis even in the eldest generation. Proliferating somatic and germline cells of younger generations expressed a Botryllus myc homolog (BpMyc), but adult tissues did not. This result strongly suggests that in B. primigenus undifferentiated progenitor cells are discernible from possible adult stem cells by the presence or absence of BpMyc.
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Affiliation(s)
- Kazuo Kawamura
- Laboratory of Cellular and Molecular Biotechnology, Faculty of Science, Kochi University, Kochi, Japan.
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21
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Epstein-Barr virus nuclear antigen 3C interacts with and enhances the stability of the c-Myc oncoprotein. J Virol 2008; 82:4082-90. [PMID: 18256156 DOI: 10.1128/jvi.02500-07] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Epstein-Barr virus (EBV) was the first human DNA virus to be associated with cancer. Its oncogenic potential was further demonstrated by its ability to transform primary B lymphocytes in vitro. EBV nuclear antigen 3C (EBNA3C) is one of a small subset of latent antigens critical for the transformation of human primary B lymphocytes. Although EBNA3C has been shown to modulate several cellular functions, additional targets involved in cellular transformation remain to be explored. EBNA3C can recruit key components of the SCF(Skp2) ubiquitin ligase complex. In this report, we show that EBNA3C residues 130 to 190, previously shown to bind to the SCF(Skp2) complex, also can strongly associate with the c-Myc oncoprotein. Additionally, the interaction of EBNA3C with c-Myc was mapped to the region of c-Myc that includes the highly conserved Skp2 binding domain. Skp2 has been shown to regulate c-Myc stability and also has been shown to function as a coactivator of transcription for c-Myc target genes. We now show that the EBV latent oncoprotein EBNA3C can stabilize c-Myc and that the recruitment of both c-Myc and its cofactor Skp2 to c-Myc-dependent promoters can enhance c-Myc-dependent transcription. This same region of EBNA3C also recruits and modulates the activity of retinoblastoma and p27, both major regulators of the mammalian cell cycle. The inclusion of c-Myc in the group of cellular targets modulated by this domain further accentuates the importance of these critical residues of EBNA3C in bypassing the cell cycle checkpoints.
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Yun JS, Rust JM, Ishimaru T, Díaz E. A novel role of the Mad family member Mad3 in cerebellar granule neuron precursor proliferation. Mol Cell Biol 2007; 27:8178-89. [PMID: 17893326 PMCID: PMC2169189 DOI: 10.1128/mcb.00656-06] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
During development, Sonic hedgehog (Shh) regulates the proliferation of cerebellar granule neuron precursors (GNPs) in part via expression of Nmyc. We present evidence supporting a novel role for the Mad family member Mad3 in the Shh pathway to regulate Nmyc expression and GNP proliferation. Mad3 mRNA is transiently expressed in GNPs during proliferation. Cultured GNPs express Mad3 in response to Shh stimulation in a cyclopamine-dependent manner. Mad3 is necessary for Shh-dependent GNP proliferation as measured by bromodeoxyuridine incorporation and Nmyc expression. Furthermore, Mad3 overexpression, but not that of other Mad proteins, is sufficient to induce GNP proliferation in the absence of Shh. Structure-function analysis revealed that Max dimerization and recruitment of the mSin3 corepressor are required for Mad3-mediated GNP proliferation. Surprisingly, basic-domain-dependent DNA binding of Mad3 is not required, suggesting that Mad3 interacts with other DNA binding proteins to repress transcription. Interestingly, cerebellar tumors and pretumor cells derived from patched heterozygous mice express high levels of Mad3 compared with adjacent normal cerebellar tissue. Our studies support a novel role for Mad3 in cerebellar GNP proliferation and possibly tumorigenesis, and they challenge the current paradigm that Mad3 should antagonize Nmyc by competition for direct DNA binding via Max dimerization.
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Affiliation(s)
- Jun-Soo Yun
- Department of Pharmacology, UC Davis School of Medicine, Davis, CA 95616, USA
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Kim SJ, Lee KH, Lee YS, Mun EG, Kwon DY, Cha YS. Transcriptome analysis and promoter sequence studies on early adipogenesis in 3T3-L1 cells. Nutr Res Pract 2007; 1:19-28. [PMID: 20535381 PMCID: PMC2882572 DOI: 10.4162/nrp.2007.1.1.19] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2007] [Revised: 03/02/2007] [Accepted: 03/05/2007] [Indexed: 12/13/2022] Open
Abstract
To identify regulatory molecules which play key roles in the development of obesity, we investigated the transcriptional profiles in 3T3-L1 cells at early stage of differentiation and analyzed the promoter sequences of differentially regulated genes. One hundred and sixty-one (161) genes were found to have significant changes in expression at the 2nd day following treatment with differentiation cocktail. Among them, 86 transcripts were up-regulated and 75 transcripts were down-regulated. The 161 transcripts were classified into 10 categories according to their functional roles; cytoskeleton, cell adhesion, immune, defense response, metabolism, protein modification, protein metabolism, regulation of transcription, signal transduction and transporter. To identify transcription factors likely involved in regulating these differentially expressed genes, we analyzed the promoter sequences of up- or -down regulated genes for the presence of transcription factor binding sites (TFBSs). Based on coincidence of regulatory sites, we have identified candidate transcription factors (TFs), which include those previously known to be involved in adipogenesis (CREB, OCT-1 and c-Myc). Among them, c-Myc was also identified by our microarray data. Our approach to take advantage of the resource of the human genome sequences and the results from our microarray experiments should be validated by further studies of promoter occupancy and TF perturbation.
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Affiliation(s)
- Su-Jong Kim
- Department of Biochemistry, College of Medicine, Hanyang University, Seoul 133-791, Korea
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24
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Abstract
The small bHLHZip protein MAX functions at the center of a transcription factor network that governs many aspects of cell behavior, including cell proliferation and tumorigenesis. MAX serves as a cofactor for DNA binding by the various members of this network, which include the MYC family of oncoproteins and a group of putative MYC antagonists that include MNT, MXD1-4 (formerly MAD1, MXI1, MAD3 and MAD4) and MGA. The many heterodimerization partners of MAX raises questions concerning the dynamics of MAX interactions and the functional consequences of the switching of Max partners. Here we review the activities of MAX, its interaction partners, and recent results showing that tissues lacking the MAX-interacting protein MNT are predisposed to tumor formation.
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Affiliation(s)
- Peter J Hurlin
- Shriners Hospitals for Children and Department of Cell and Developmental Biology, Oregon Health & Science University, Portland, OR 97201, USA.
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25
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Rottmann S, Lüscher B. The Mad side of the Max network: antagonizing the function of Myc and more. Curr Top Microbiol Immunol 2006; 302:63-122. [PMID: 16620026 DOI: 10.1007/3-540-32952-8_4] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
A significant body of evidence has been accumulated that demonstrates decisive roles of members of the Myc/Max/Mad network in the control of various aspects of cell behavior, including proliferation, differentiation, and apoptosis. The components of this network serve as transcriptional regulators. Mad family members, including Mad1, Mxi1, Mad3, Mad4, Mnt, and Mga, function in part as antagonists of Myc oncoproteins. At the molecular level this antagonism is reflected by the different cofactor/chromatin remodeling complexes that are recruited by Myc and Mad family members. One important function of the latter is their ability to repress gene transcription. In this review we summarize the current view of how this repression is achieved and what the consequences of Mad action are for cell behavior. In addition, we point out some of the many aspects that have not been clarified and thus leave us with a rather incomplete picture of the functions, both molecular and at the cellular level, of Mad family members.
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Affiliation(s)
- S Rottmann
- Abteilung Biochemie und Molekularbiologie, Institut für Biochemie, Klinikum der RWTH, Pauwelsstrasse 30, 52074 Aachen, Germany
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26
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Abstract
Deregulation of Myc expression is a common feature in cancer and leads to tumor formation in experimental model systems. There are several potential barriers that Myc must overcome in order to promote tumorigenesis, including its propensity to sensitize many cell types to apoptotic cell death. Myc activities appear also to be constrained and fine-tuned by a set of proteins that include the Mxd (formerly named Mad) family and the related protein Mnt. Like Myc-family proteins, Mxd and Mnt proteins use Max as a cofactor for DNA binding. But Mnt-Max and Mxd-Max complexes are transcriptional repressors and can antagonize the transcriptional activation function of Myc-Max. Studies examining the relationship between Myc, Mxd and Mnt proteins suggest that whereas Mnt plays a general role as a Myc antagonist, Mxd proteins have more specialized roles as Myc antagonist that is probably related to their more restricted expression patterns. The interplay between these proteins is postulated to fine-tune Myc activity for cell-cycle entry and exit, proliferation rate and apoptosis.
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Affiliation(s)
- C William Hooker
- Shriners Hospitals for Children and Department of Cell and Developmental Biology, Oregon Health and Science University, 3101 SW Sam Jackson Park Rd, Portland, OR 97239, USA
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27
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Klisch TJ, Souopgui J, Juergens K, Rust B, Pieler T, Henningfeld KA. Mxi1 is essential for neurogenesis in Xenopus and acts by bridging the pan-neural and proneural genes. Dev Biol 2006; 292:470-85. [PMID: 16457797 DOI: 10.1016/j.ydbio.2005.12.037] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2005] [Revised: 12/14/2005] [Accepted: 12/16/2005] [Indexed: 12/25/2022]
Abstract
We have isolated and characterized Xenopus Mxi1, a member of the Myc/Max/Mad family of bHLHZip transcription factors. Xmxi1 transcripts are present during gastrulation and early neurula stages, earlier and in broader domains as compared to the neuronal determination factor neurogenin (X-ngnr-1). Consistent with an early role in neurogenesis, Xmxi1 is positively regulated by Sox3, SoxD, and proneural genes, as well as negatively by the Notch pathway. Loss-of-function experiments demonstrate an essential role for Xmxi1 in the establishment of a mature neural state that can be activated by factors that induce neuronal differentiation, such as SoxD and X-ngnr-1. Overexpression of Xmxi1 in Xenopus embryos results in ectopic activation of Sox3, an early pan-neural marker of proliferating neural precursor cells. Within the neural plate, the neuronal differentiation marker N-tubulin and cell cycle control genes such as XPak3 and p27(Xic1) are inhibited, but the expression of early determination and differentiation markers, including X-ngnr-1 and X-MyT1, is not affected. Inhibition of neuronal differentiation by Xmxi1 is only transient, and, at early tailbud stages, both endogenous and ectopic neurogenesis are observed. While Xmxi1 enhances cell proliferation and apoptosis in the early Xenopus embryo, both activities appear not to be required for the function of Xmxi1 in primary neurogenesis.
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Affiliation(s)
- Tiemo J Klisch
- DFG-Center of Molecular Physiology of the Brain, Department of Developmental Biochemistry, University of Göttingen, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany
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28
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Sanders JA, Gruppuso PA. Coordinated regulation of c-Myc and Max in rat liver development. Am J Physiol Gastrointest Liver Physiol 2006; 290:G145-55. [PMID: 16150871 DOI: 10.1152/ajpgi.00545.2004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The processes of liver development and regeneration involve regulation of a key network of transcription factors, the c-myc/max/mad network. This network regulates the expression of genes involved in hepatocyte proliferation, growth, metabolism, and differentiation. In previous studies on the expression and localization of c-Myc in the fetal and adult liver, we made the unexpected observation that c-Myc content was similar in the two. However, c-Myc was localized predominantly to the nucleolus in the adult liver. On the basis of this finding, we went on to characterize the expression patterns of the other members of the network, max and mad, comparing their regulation during late fetal development with the proliferation of mature hepatocytes that is seen in liver regeneration. We found that Max content, rather than being constitutive, as predicted by other studies, was elevated in the fetal liver compared with the adult liver. Its content correlated with hepatocyte proliferation during the perinatal transition. In contrast, mad4 expression was decreased in the fetal liver compared with the adult liver. Nucleolar localization of c-Myc coincided with changes in Max content. To explore this relationship, we overexpressed Max in cultured adult hepatocytes. High levels of Max resulted in a shift in c-Myc localization from nucleolar to diffuse nuclear. In contrast, liver regeneration was associated with an increase in c-Myc content but no change in Max content. We conclude that the regulation of Max content during liver development and its potential role in determining c-Myc localization are means by which Max may control the biological activity of the c-Myc/Max/Mad network during liver development.
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Affiliation(s)
- Jennifer A Sanders
- Department of Pediatrics, Rhode Island Hospital and Brown University, Providence, RI 02903, USA
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29
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Hu J, Banerjee A, Goss DJ. Assembly of b/HLH/z proteins c-Myc, Max, and Mad1 with cognate DNA: importance of protein-protein and protein-DNA interactions. Biochemistry 2005; 44:11855-63. [PMID: 16128587 PMCID: PMC3225066 DOI: 10.1021/bi050206i] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Among the best characterized of the transcription factors are the b/HLH/z proteins: USF, Max, Myc, and Mad. These proteins bind to the DNA E-box, a six base pair sequence, CACGTG. Max and Myc form a heterodimer that has strong oncogenic potential but can also repress transcription, while Mad and Max form a heterodimer that acts as a transcription repressor. We have used fluorescence anisotropy to measure protein-protein and protein-DNA affinity. The specific binding between MLP DNA and Max (K = 2.2 +/- 0.5 nM) is about 10-fold higher affinity than LCR DNA and about 100-fold higher than for a nonspecific DNA. USF has a similar binding affinity as Max to MLP DNA (K = 15 +/- 10 nM), but Max binds more tightly to LCR and nonspecific DNA. A series of oligonucleotides designated E-box, half-E-box, and non-E-box were constructed to examine the effects of DNA sequence. The binding results indicate that for Max protein most of the binding energy can be attributed to individual elements with little cooperativity among the two halves of the E-box. Further studies measured the equilibria for the entire thermodynamic cycle of monomer-dimer-DNA interactions. Surprisingly, the affinity of the Max monomer-DNA for the second monomer was greatly reduced (K for the first monomer in the nanomolar range and for the second monomer in the micromolar range). Looked at from the perspective of the Max protein, the binding of DNA to Max significantly reduces the affinity of the Max protein for the second monomer, whether the second monomer is Myc, Mad, or Max. These data suggest the importance of protein-protein interactions in assembly of a transcription initiation complex.
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Affiliation(s)
| | | | - Dixie J. Goss
- To whom correspondence should be addressed: Department of Chemistry, Hunter College of CUNY 695 Park Ave, New York, NY 10021 Tel: 212-772-5383; Fax: 212-772-5332;
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30
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Loo LWM, Secombe J, Little JT, Carlos LS, Yost C, Cheng PF, Flynn EM, Edgar BA, Eisenman RN. The transcriptional repressor dMnt is a regulator of growth in Drosophila melanogaster. Mol Cell Biol 2005; 25:7078-91. [PMID: 16055719 PMCID: PMC1190258 DOI: 10.1128/mcb.25.16.7078-7091.2005] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The Myc-Max-Mad/Mnt network of transcription factors has been implicated in oncogenesis and the regulation of proliferation in vertebrate cells. The identification of Myc and Max homologs in Drosophila melanogaster has demonstrated a critical role for dMyc in cell growth control. In this report, we identify and characterize the third member of this network, dMnt, the sole fly homolog of the mammalian Mnt and Mad family of transcriptional repressors. dMnt possesses two regions characteristic of Mad and Mnt proteins: a basic helix-loop-helix-zipper domain, through which it dimerizes with dMax to form a sequence-specific DNA binding complex, and a Sin-interacting domain, which mediates interaction with the dSin3 corepressor. Using the upstream activation sequence/GAL4 system, we show that expression of dMnt results in an inhibition of cellular growth and proliferation. Furthermore, we have generated a dMnt null allele, which results in flies with larger cells, increased weight, and decreased life span compared to wild-type flies. Our results demonstrate that dMnt is a transcriptional repressor that regulates D. melanogaster body size.
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Affiliation(s)
- Lenora W M Loo
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109-1024, USA
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31
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Juergens K, Rust B, Pieler T, Henningfeld KA. Isolation and comparative expression analysis of the Myc-regulatory proteins Mad1, Mad3, and Mnt duringXenopus development. Dev Dyn 2005; 233:1554-9. [PMID: 15973701 DOI: 10.1002/dvdy.20470] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The Myc-Max-Mad network of transcription factors plays an essential role in many cellular processes such as proliferation, differentiation, and apoptosis. The Mad proteins heterodimerize with Max, function as transcriptional repressors, and are capable of antagonizing the transforming activity of Myc. We report on the isolation of Xmad1, Xmad3, and Xmnt, novel Xenopus genes belonging to the Mad family. We also describe their temporal and spatial expression patterns during Xenopus embryogenesis. Xmad1 expression is found primarily in cells that have undergone terminal differentiation including the notochord, floor plate, and cement gland. Xmad3 transcripts are expressed broadly throughout the central nervous system and the eye, starting at neurula stages. In contrast, Xmnt expression in the CNS was localized anteriorly and, in addition, is present in the migrating neural crest cells. This study demonstrates the Mads are expressed in specific and mostly nonoverlapping patterns, suggesting distinct roles during embryogenesis.
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Affiliation(s)
- Kathrin Juergens
- Department of Developmental Biochemistry, University of Goettingen, Goettingen, Germany
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32
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Hultquist A, Cetinkaya C, Wu S, Castell A, Erlandsson A, Larsson LG. Mad 1 Inhibits Cell Growth and Proliferation but Does Not Promote Differentiation or Overall Survival in Human U-937 Monoblasts. Mol Cancer Res 2004. [DOI: 10.1158/1541-7786.464.2.8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
The Mad family proteins are transcriptional repressors belonging to the basic region/helix-loop-helix/leucine zipper family. They share a common obligatory dimerization partner, Max, with the oncoprotein c-Myc and antagonize the function of Myc to activate transcription. The Myc/Max/Mad network has therefore been suggested to function as a molecular switch that regulates cell growth and differentiation by controlling a common set of genes. To study the biological consequences of Mad1 expression for hematopoietic cell growth and differentiation, we used the U-937 monocytic differentiation model to generate cells with inducible Mad1 expression using the reversed tetracycline-controlled transactivator system. The elevated expression of Mad1 in these cells resulted in increased Mad1/Max heterodimer formation correlating with reduced expression of the Myc/Mad target gene ODC. Mad1-expressing U-937 cells in suspension culture proliferated slower and exhibited an increased number of cells in the G1 phase of the cell cycle. Further, growth in semisolid medium was almost completely inhibited. Mad1-expression, however, neither enforced spontaneous differentiation nor enhanced differentiation induced by the phorbol ester 12-O-tetradecanoylphorbol-13-acetate, retinoic acid (RA), or vitamin D3 but rather led to delayed RA-stimulated differentiation. Mad1-expressing cells were further found to be reduced in cell size in all phases of the cells cycle and particularly in response to RA-induced differentiation. Unexpectedly, whereas Fas-induced apoptosis was slightly attenuated in Mad1-expressing U-937 cells, Mad1 sensitized the cells to tumor necrosis factor–α-induced apoptosis. These results suggest that Mad1 primarily regulates cell growth and proliferation in these cells, whereas its role in cellular differentiation and survival seems to be more complex.
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Affiliation(s)
- Anne Hultquist
- 1Department of Genetics and Pathology, University of Uppsala and
- 2Department of Plant Biology and Forest Genetics, Uppsala Genetic Center, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Cihan Cetinkaya
- 2Department of Plant Biology and Forest Genetics, Uppsala Genetic Center, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Siqin Wu
- 2Department of Plant Biology and Forest Genetics, Uppsala Genetic Center, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Alina Castell
- 2Department of Plant Biology and Forest Genetics, Uppsala Genetic Center, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Anna Erlandsson
- 1Department of Genetics and Pathology, University of Uppsala and
| | - Lars-Gunnar Larsson
- 1Department of Genetics and Pathology, University of Uppsala and
- 2Department of Plant Biology and Forest Genetics, Uppsala Genetic Center, Swedish University of Agricultural Sciences, Uppsala, Sweden
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33
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Jiang DJ, Yu HX, Hexige SY, Guo ZK, Wang X, Ma LJ, Chen Z, Zhao SY, Yu L. Human Liver Specific Transcriptional Factor TCP10L Binds to MAD4. BMB Rep 2004; 37:402-7. [PMID: 15469726 DOI: 10.5483/bmbrep.2004.37.4.402] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A human gene T-complex protein 10 like (TCP10L) was cloned in our lab. A previous study showed that it expressed specifically in the liver and testis. A transcription experiment revealed that TCP10L was a transcription factor with transcription inhibition activity. In this study, the human MAD4 was identified to interact with TCP10L by a yeast two-hybrid screen. This finding was confirmed by immunoprecipitation and subcellular localization experiments. As MAD4 is a member of the MAD family, which antagonizes the functions of MYC and promotes cell differentiation, the biological function of the interaction between TCP10L and MAD4 may be to maintain the differentiation state in liver cells. Also, we propose that the up-regulation of Myc is caused by the down-regulation of TCP10L in human hepatocarcinomas.
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Affiliation(s)
- Dao-Jun Jiang
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Science, Fudan University, Shanghai 200433, P.R. China
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34
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Fox EJ, Stubbs SA, Kyaw Tun J, Leek JP, Markham AF, Wright SC. PRELI (protein of relevant evolutionary and lymphoid interest) is located within an evolutionarily conserved gene cluster on chromosome 5q34-q35 and encodes a novel mitochondrial protein. Biochem J 2004; 378:817-25. [PMID: 14640972 PMCID: PMC1223999 DOI: 10.1042/bj20031504] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2003] [Revised: 11/13/2003] [Accepted: 11/26/2003] [Indexed: 11/17/2022]
Abstract
The characterization of mitochondrial proteins is important for the understanding of both normal cellular function and mitochondrial disease. In the present study we identify a novel mitochondrial protein, PRELI (protein of relevant evolutionary and lymphoid interest), that is encoded within the evolutionarily conserved MAD3/PRELI/RAB24 gene cluster located at chromosome 5q34-q35. Mouse Preli is expressed at high levels in all settings analysed; it is co-expressed with Rab24 from a strong bi-directional promoter, and is regulated independently from the S-phase-specific Mad3 gene located at its 3' end. PRELI contains a stand-alone 170 amino acid PRELI/MSF1p' motif at its N-terminus. This domain is found in a variety of proteins from diverse eukaryotes including yeast, Drosophila and mammals, but its function is unknown, and the subcellular location of higher eukaryotic PRELI/MSF1P' proteins has not been determined previously. We show here that PRELI is located in the mitochondria, and by using green-fluorescent-protein fusion proteins we identify a mitochondrial targeting signal at its N-terminus.
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Affiliation(s)
- Elizabeth J Fox
- School of Biochemistry and Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
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35
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Hurlin PJ, Dezfouli S. Functions of myc:max in the control of cell proliferation and tumorigenesis. INTERNATIONAL REVIEW OF CYTOLOGY 2004; 238:183-226. [PMID: 15364199 DOI: 10.1016/s0074-7696(04)38004-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Deregulation and elevated expression of members of the Myc family of bHLHZip transcription factors are observed in a high percentage of tumors. This close association with human cancers has led to a tremendous effort to define their biological and biochemical activities. Although Myc family proteins have the capacity to elicit a wide range of cell behaviors, their principal function appears to be to drive cells into the cell cycle and to keep them there. However, forced expression of Myc profoundly sensitizes normal cells to apoptosis. Therefore, tumor formation caused by deregulated Myc expression requires cooperating events that disrupt pathways that mediate apoptosis. Myc-dependent tumor formation may also be impeded by a set of related bHLHZip proteins with the demonstrated potential to act as Myc antagonists in cell culture experiments. In this review, we examine the complex activities of Myc family proteins and how their actions might be regulated in the context of a network of bHLHZip proteins.
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Affiliation(s)
- Peter J Hurlin
- Portland Shriners Hospitals for Children and Department of Cell and Developmental Biology Oregon Health Sciences University, Portland, Oregon 97201, USA
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36
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Siegel PM, Shu W, Massagué J. Mad upregulation and Id2 repression accompany transforming growth factor (TGF)-beta-mediated epithelial cell growth suppression. J Biol Chem 2003; 278:35444-50. [PMID: 12824180 DOI: 10.1074/jbc.m301413200] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The growth inhibitory cytokine TGF-beta enforces homeostasis of epithelia by activating processes such as cell cycle arrest and apoptosis. Id2 expression is often highest in proliferating epithelial cells and declines during differentiation. Recently, Id2 expression has been found to depend on Myc-Max transcriptional complexes. We observed that TGF-beta signaling inhibits Id2 expression in human and mouse epithelial cell lines from different tissue origins. Furthermore, the observed Id2 down-regulation by TGF-beta in mouse mammary epithelial cells occurs without a concurrent drop in c-Myc levels. However, sustained Id2 repression in these cells and in human keratinocytes coincides with induction of the Myc antagonistic repressors Mad2 and Mad4, decreased formation of Myc-Max heterodimers and the replacement of Myc-Max complexes with Mad-Max complexes on the Id2 promoter. These results argue that induction of Mad expression and Id2 down-regulation are important events during the TGF-beta cytostatic program in epithelial cells.
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Affiliation(s)
- Peter M Siegel
- Cell Biology Program and Howard Hughes Medical Institute, Memorial Sloan-Kettering Cancer Center, New York, New York 10021
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37
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Nikiforov MA, Popov N, Kotenko I, Henriksson M, Cole MD. The Mad and Myc basic domains are functionally equivalent. J Biol Chem 2003; 278:11094-9. [PMID: 12538578 DOI: 10.1074/jbc.m212298200] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Myc/Max/Mad family of transcription factors plays a fundamental role in the regulation of cell proliferation, oncogenic transformation, and cell differentiation. However, it remains unclear whether different heterodimers, such as Myc/Max and Mad/Max, recognize the same or different target genes in vivo. We show by chromatin immunoprecipitation that Myc target genes are also recognized by Mad1 in differentiated HL60 cells. We also substituted the complete basic region of Myc for the corresponding region of Mad. Wild-type c-Myc was then compared with c-Myc(Mad-BR) in oncogenic transformation, regulation of cell proliferation, induction of apoptosis, activation of chromosomal gene expression, and direct binding to chromosomal sites by chromatin immunoprecipitation. We find that the wild-type c-Myc and c-Myc/MadBR proteins have indistinguishable biological activity and target gene recognition in vivo. These data are consistent with a model in which Myc and Mad regulate a common set of target genes.
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Affiliation(s)
- Mikhail A Nikiforov
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA
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38
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Fox EJ, Wright SC. The transcriptional repressor gene Mad3 is a novel target for regulation by E2F1. Biochem J 2003; 370:307-13. [PMID: 12444919 PMCID: PMC1223166 DOI: 10.1042/bj20021583] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2002] [Revised: 11/19/2002] [Accepted: 11/21/2002] [Indexed: 01/28/2023]
Abstract
Mad family proteins are transcriptional repressors that antagonize the activity of the c- Myc proto-oncogene product. Mad3 is expressed specifically during the S-phase of the cell cycle in both proliferating and differentiating cells, suggesting that its biological function is probably linked to processes that occur during this period. To determine the mechanisms that regulate the cell-cycle-specific transcription of Mad3, we used reporter gene assays in stably transfected fibroblasts. We show that the activation of Mad3 at the G1-S boundary is mediated by a single E2F (E2 promoter binding factor)-binding site within the 5'-flanking region of the gene. Mutation of this element eliminated transcriptional activation at S-phase, suggesting that the positively acting E2F proteins play a role in Mad3 regulation. Using electrophoretic mobility-shift assays and chromatin immunoprecipitation, we show that E2F1 binds to the Mad3 5'-flanking region both in vitro and in vivo. We thus identify Mad3 as a novel transcriptional target of E2F1.
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Affiliation(s)
- Elizabeth J Fox
- School of Biochemistry and Molecular Biology, University of Leeds, Mount Preston Street, Leeds LS2 9JT, UK
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39
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Kime L, Wright SC. Mad4 is regulated by a transcriptional repressor complex that contains Miz-1 and c-Myc. Biochem J 2003; 370:291-8. [PMID: 12418961 PMCID: PMC1223147 DOI: 10.1042/bj20021679] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2002] [Accepted: 11/06/2002] [Indexed: 12/22/2022]
Abstract
Myc and Mad family proteins are central regulators of cellular proliferation and differentiation. We show that various Mad family genes have distinct patterns of expression during the chemically induced differentiation of mouse erythroleukaemia (MEL) cells, suggesting that they each serve a different function. Mad4 RNA is highly induced and persists in terminally differentiated cells, in agreement with observations in other systems. Using reporter gene assays in stably transfected MEL cells, we show that induction of Mad4 is mediated by a 49 nt core promoter region. We demonstrate that the initiator element is required for Mad4 activation, and show that induction is associated with the loss from the initiator of a complex that contains Miz-1 and c-Myc. Miz-1 activates the Mad4 promoter in transient transfection assays, and this effect is antagonized by c-Myc. We therefore identify Mad4 as a novel target of transcriptional repression by c-Myc. These data suggest that the expression of Mad4 in proliferating undifferentiated cells is suppressed by the binding of a c-Myc-Miz-1 repressor complex at the initiator, and that the activation of Mad4 during differentiation results, at least in part, from a decrease in c-Myc-mediated repression.
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Affiliation(s)
- Louise Kime
- School of Biochemistry and Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K
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40
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Cerni C, Skrzypek B, Popov N, Sasgary S, Schmidt G, Larsson LG, Lüscher B, Henriksson M. Repression of in vivo growth of Myc/Ras transformed tumor cells by Mad1. Oncogene 2002; 21:447-59. [PMID: 11821957 DOI: 10.1038/sj.onc.1205107] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2001] [Revised: 10/09/2001] [Accepted: 10/29/2001] [Indexed: 11/09/2022]
Abstract
The Myc/Max/Mad network of transcriptional regulatory proteins plays an essential role in cell proliferation, growth, apoptosis, and differentiation. Whereas Myc proteins affect cell cycle progression positively, Mad proteins are negative regulators of cell proliferation. It has been shown in several in vitro systems that Mad proteins antagonize c-Myc functions. In this report we describe the inhibition of tumor cell outgrowth in vivo by Mad1 expression. Transformed cell lines were generated by co-transfection of c-myc, c-H-ras, and a chimeric mad1ER construct into primary rat embryo cells (MRMad1ER cells). Activation of Mad1 by 4-Hydroxy-Tamoxifen (OHT) resulted in abrogation of telomerase activity, reduced cloning efficiency, and decreased proportion of cells in S phase. Injection of MRMad1ER cells into syngenic rats induced aggressively growing tumors after a short latency period. This tumor growth was inhibited by OHT-treatment of animals, with the extent of inhibition correlating with the amount of OHT injected. No effect of OHT on tumor growth was observed with similarly transformed Myc/Ras cell lines which did not express Mad1ER. These data demonstrate that Mad1 is able to suppress Myc/Ras-mediated transformation under in vivo conditions.
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MESH Headings
- Animals
- Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
- Blotting, Western
- Cell Cycle Proteins/metabolism
- Cell Division/drug effects
- Cell Division/genetics
- Cell Line, Transformed
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/metabolism
- Cell Transformation, Neoplastic/pathology
- Cells, Cultured
- Flow Cytometry
- Gene Expression Regulation, Neoplastic
- Genes, myc/genetics
- Genes, ras/genetics
- Male
- Nuclear Proteins
- Phosphoproteins/genetics
- Phosphoproteins/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats
- Rats, Inbred F344
- Repressor Proteins/genetics
- Repressor Proteins/metabolism
- Tamoxifen/analogs & derivatives
- Tamoxifen/pharmacology
- Telomerase/antagonists & inhibitors
- Telomerase/metabolism
- Transgenes/genetics
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Affiliation(s)
- Christa Cerni
- Institute of Cancer Research, University of Vienna, Borschkegasse 8a, A-1090 Wien, Austria.
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41
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Abstract
Members of the Myc family of transcription factors are key regulators of cell proliferation, and excessive levels of Myc lead to tumor formation. Mad family proteins are related to Myc, but they antagonize the oncogenic activity of Myc in cell-culture assays. Here, we examine current models of Mad function and the relationship between Mad and Myc in cell proliferation, differentiation and tumorigenesis.
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Affiliation(s)
- Z Q Zhou
- Shriners Hospitals for Children, Department of Cell and Developmental Biology, Oregon Health Sciences University, 3101 Sam Jackson Park Road, Portland, OR 97201, USA.
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42
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43
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Abstract
The retinoic acid receptor alpha gene is the target of chromosomal rearrangements in all cases of acute promyelocytic leukemia (APL). This recurrent involvement of RARalpha in the pathogenesis of APL is likely to reflect an important role played by this receptor during the differentiation of immature myeloid cells to neutrophils. RARalpha is a negative regulator of promyelocyte differentiation when not complexed with RA, and stimulates this differentiation when bound to RA. Since RARs are dispensable for the generation of mature neutrophils, their role thus appears to be to modulatory, rather than obligatory, for the control of neutrophil differentiation. In vitro, retinoic acid is also a potent inducer of neutrophil cell fate, suggesting that it might play a role in the commitment of pluripotent hematopoietic progenitors to the neutrophil lineage. Thus, the APL translocations target an important regulator of myeloid cell differentiation.
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Affiliation(s)
- P Kastner
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS-INSERM-ULP, 1 rue Laurent Fries, BP163, 67404 Illkirch Cedex, C.U. de Strasbourg, France
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44
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Fox EJ, Wright SC. S-phase-specific expression of the Mad3 gene in proliferating and differentiating cells. Biochem J 2001; 359:361-7. [PMID: 11583582 PMCID: PMC1222154 DOI: 10.1042/0264-6021:3590361] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The Myc/Max/Mad transcription factor network plays a central role in the control of cellular proliferation, differentiation and apoptosis. In order to elucidate the biological function of Mad3, we have analysed the precise temporal patterns of Mad3 mRNA expression during the cell cycle and differentiation in cultured cells. We show that Mad3 is induced at the G1/S transition in proliferating cells; expression persists throughout S-phase, and then declines as cells pass through G2 and mitosis. The expression pattern of Mad3 is coincident with that of Cdc2 throughout the cell cycle. In contrast, the expression of Mad3 during differentiation of cultured mouse erythroleukemia cells shows two transient peaks of induction. The first of these occurs at the onset of differentiation, and does not correlate with the S-phase of the cell cycle, whereas the second is coincident with the S-phase burst that precedes the terminal stages of differentiation. Our results therefore suggest that Mad3 serves a cell-cycle-related function in both proliferating and differentiating cells, and that it may also have a distinct role at various stages of differentiation.
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Affiliation(s)
- E J Fox
- School of Biochemistry and Molecular Biology, University of Leeds, Mount Preston Street, Leeds LS2 9JT, UK
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45
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Grandori C, Cowley SM, James LP, Eisenman RN. The Myc/Max/Mad network and the transcriptional control of cell behavior. Annu Rev Cell Dev Biol 2001; 16:653-99. [PMID: 11031250 DOI: 10.1146/annurev.cellbio.16.1.653] [Citation(s) in RCA: 978] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The Myc/Max/Mad network comprises a group of transcription factors whose distinct interactions result in gene-specific transcriptional activation or repression. A great deal of research indicates that the functions of the network play roles in cell proliferation, differentiation, and death. In this review we focus on the Myc and Mad protein families and attempt to relate their biological functions to their transcriptional activities and gene targets. Both Myc and Mad, as well as the more recently described Mnt and Mga proteins, form heterodimers with Max, permitting binding to specific DNA sequences. These DNA-bound heterodimers recruit coactivator or corepressor complexes that generate alterations in chromatin structure, which in turn modulate transcription. Initial identification of target genes suggests that the network regulates genes involved in the cell cycle, growth, life span, and morphology. Because Myc and Mad proteins are expressed in response to diverse signaling pathways, the network can be viewed as a functional module which acts to convert environmental signals into specific gene-regulatory programs.
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Affiliation(s)
- C Grandori
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109-1024, USA.
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46
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Stoneley M, Spencer JP, Wright SC. An internal ribosome entry segment in the 5' untranslated region of the mnt gene. Oncogene 2001; 20:893-7. [PMID: 11314024 DOI: 10.1038/sj.onc.1204157] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2000] [Revised: 12/05/2000] [Accepted: 12/07/2000] [Indexed: 11/08/2022]
Abstract
Mnt is a transcriptional repressor related to the Myc/Mad family of transcription factors. It is expressed in proliferating, resting and differentiating cells and is believed to antagonize the function of Myc. Here we have characterized the major transcription initiation site of the mnt gene. In doing so we noted a remarkable level of sequence conservation between the murine and human 5' untranslated regions. Our experiments revealed that this sequence contains an internal ribosome entry segment (IRES). In addition, we show that sequences at both the 5' and 3' end of the IRES are essential for its function. These findings indicate that mnt can be translated by internal initiation. Such a mechanism may allow efficient Mnt synthesis when cap-dependent translation initiation is reduced.
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Affiliation(s)
- M Stoneley
- School of Biochemistry and Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
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47
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Quéva C, McArthur GA, Iritani BM, Eisenman RN. Targeted deletion of the S-phase-specific Myc antagonist Mad3 sensitizes neuronal and lymphoid cells to radiation-induced apoptosis. Mol Cell Biol 2001; 21:703-12. [PMID: 11154258 PMCID: PMC86662 DOI: 10.1128/mcb.21.3.703-712.2001] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Mad family comprises four basic-helix-loop-helix/leucine zipper proteins, Mad1, Mxi1, Mad3, and Mad4, which heterodimerize with Max and function as transcriptional repressors. The balance between Myc-Max and Mad-Max complexes has been postulated to influence cell proliferation and differentiation. The expression patterns of Mad family genes are complex, but in general, the induction of most family members is linked to cell cycle exit and differentiation. The expression pattern of mad3 is unusual in that mad3 mRNA and protein were found to be restricted to proliferating cells prior to differentiation. We show here that during murine development mad3 is specifically expressed in the S phase of the cell cycle in neuronal progenitor cells that are committed to differentiation. To investigate mad3 function, we disrupted the mad3 gene by homologous recombination in mice. No defect in cell cycle exit and differentiation could be detected in mad3 homozygous mutant mice. However, upon gamma irradiation, increased cell death of thymocytes and neural progenitor cells was observed, implicating mad3 in the regulation of the cellular response to DNA damage.
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Affiliation(s)
- C Quéva
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109-1024, USA
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