1
|
Transcription factor c-Myb: novel prognostic factor in osteosarcoma. Clin Exp Metastasis 2022; 39:375-390. [PMID: 34994868 DOI: 10.1007/s10585-021-10145-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 12/28/2021] [Indexed: 12/21/2022]
Abstract
The transcription factor c-Myb is an oncoprotein promoting cell proliferation and survival when aberrantly activated/expressed, thus contributing to malignant transformation. Overexpression of c-Myb has been found in leukemias, breast, colon and adenoid cystic carcinoma. Recent studies revealed its expression also in osteosarcoma cell lines and suggested its functional importance during bone development. However, the relevance of c-Myb in control of osteosarcoma progression remains unknown. A retrospective clinical study was carried out to assess a relationship between c-Myb expression in archival osteosarcoma tissues and prognosis in a cohort of high-grade osteosarcoma patients. In addition, MYB was depleted in metastatic osteosarcoma cell lines SAOS-2 LM5 and 143B and their growth, chemosensitivity, migration and metastatic activity were determined. Immunohistochemical analysis revealed that high c-Myb expression was significantly associated with poor overall survival in the cohort and metastatic progression in young patients. Increased level of c-Myb was detected in metastatic osteosarcoma cell lines and its depletion suppressed their growth, colony-forming capacity, migration and chemoresistance in vitro in a cell line-dependent manner. MYB knock-out resulted in reduced metastatic activity of both SAOS-2 LM5 and 143B cell lines in immunodeficient mice. Transcriptomic analysis revealed the c-Myb-driven functional programs enriched for genes involved in the regulation of cell growth, stress response, cell adhesion and cell differentiation/morphogenesis. Wnt signaling pathway was identified as c-Myb target in osteosarcoma cells. Taken together, we identified c-Myb as a negative prognostic factor in osteosarcoma and showed its involvement in the regulation of osteosarcoma cell growth, chemosensitivity, migration and metastatic activity.
Collapse
|
2
|
Gioacchino E, Koyunlar C, Zink J, de Looper H, de Jong M, Dobrzycki T, Mahony CB, Hoogenboezem R, Bosch D, van Strien PMH, van Royen ME, French PJ, Bindels E, Gussinklo KJ, Monteiro R, Touw IP, de Pater E. Essential role for Gata2 in modulating lineage output from hematopoietic stem cells in zebrafish. Blood Adv 2021; 5:2687-2700. [PMID: 34170285 PMCID: PMC8288679 DOI: 10.1182/bloodadvances.2020002993] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 02/22/2021] [Indexed: 01/22/2023] Open
Abstract
The differentiation of hematopoietic stem cells (HSCs) is tightly controlled to ensure a proper balance between myeloid and lymphoid cell output. GATA2 is a pivotal hematopoietic transcription factor required for generation and maintenance of HSCs. GATA2 is expressed throughout development, but because of early embryonic lethality in mice, its role during adult hematopoiesis is incompletely understood. Zebrafish contains 2 orthologs of GATA2: Gata2a and Gata2b, which are expressed in different cell types. We show that the mammalian functions of GATA2 are split between these orthologs. Gata2b-deficient zebrafish have a reduction in embryonic definitive hematopoietic stem and progenitor cell (HSPC) numbers, but are viable. This allows us to uniquely study the role of GATA2 in adult hematopoiesis. gata2b mutants have impaired myeloid lineage differentiation. Interestingly, this defect arises not in granulocyte-monocyte progenitors, but in HSPCs. Gata2b-deficient HSPCs showed impaired progression of the myeloid transcriptional program, concomitant with increased coexpression of lymphoid genes. This resulted in a decrease in myeloid-programmed progenitors and a relative increase in lymphoid-programmed progenitors. This shift in the lineage output could function as an escape mechanism to avoid a block in lineage differentiation. Our study helps to deconstruct the functions of GATA2 during hematopoiesis and shows that lineage differentiation flows toward a lymphoid lineage in the absence of Gata2b.
Collapse
Affiliation(s)
| | - Cansu Koyunlar
- Department of Hematology, Erasmus MC, Rotterdam, The Netherlands
| | - Joke Zink
- Department of Hematology, Erasmus MC, Rotterdam, The Netherlands
| | - Hans de Looper
- Department of Hematology, Erasmus MC, Rotterdam, The Netherlands
- Cancer Genome Editing Center, Erasmus MC, Rotterdam, The Netherlands
| | - Madelon de Jong
- Department of Hematology, Erasmus MC, Rotterdam, The Netherlands
| | - Tomasz Dobrzycki
- Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - Christopher B. Mahony
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom; and
| | | | - Dennis Bosch
- Department of Hematology, Erasmus MC, Rotterdam, The Netherlands
| | | | - Martin E. van Royen
- Department of Pathology, Cancer Treatment Screening Facility, Erasmus MC Optical Imaging Centre, and
| | - Pim J. French
- Department of Neurology, Cancer Treatment Screening Facility, Erasmus MC, Rotterdam, The Netherlands
| | - Eric Bindels
- Department of Hematology, Erasmus MC, Rotterdam, The Netherlands
| | | | - Rui Monteiro
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom; and
| | - Ivo P. Touw
- Department of Hematology, Erasmus MC, Rotterdam, The Netherlands
| | - Emma de Pater
- Department of Hematology, Erasmus MC, Rotterdam, The Netherlands
- Cancer Genome Editing Center, Erasmus MC, Rotterdam, The Netherlands
| |
Collapse
|
3
|
Lungova V, Buchtova M, Janeckova E, Tucker AS, Knopfova L, Smarda J, Matalova E. Localization of c-MYB in differentiated cells during postnatal molar and alveolar bone development. Eur J Oral Sci 2012; 120:495-504. [DOI: 10.1111/j.1600-0722.2012.01004.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/01/2012] [Indexed: 12/12/2022]
Affiliation(s)
| | | | | | - Abigail S. Tucker
- Department of Craniofacial Development and Stem Cell Biology, and Department of Orthodontics; KCL; London; UK
| | - Lucia Knopfova
- Department of Experimental Biology; Faculty of Science; Masaryk University; Brno; Czech Republic
| | - Jan Smarda
- Department of Experimental Biology; Faculty of Science; Masaryk University; Brno; Czech Republic
| | | |
Collapse
|
4
|
Matalová E, Buchtová M, Tucker AS, Bender TP, Janečková E, Lungová V, Balková S, Smarda J. Expression and characterization of c-Myb in prenatal odontogenesis. Dev Growth Differ 2011; 53:793-803. [PMID: 21762405 DOI: 10.1111/j.1440-169x.2011.01287.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The transcription factor c-Myb is involved in the control of cell proliferation, survival and differentiation. As these processes accompany the morphogenesis of developing teeth, this work investigates the possible role of c-Myb during odontogenesis. Analysis of the expression of c-Myb in the monophyodont mouse was followed by similar analysis in a diphyodont species, the pig, which has a dentition more closely resembling that of the human. The distribution of c-Myb was correlated with the pattern of proliferation and apoptosis and the tooth phenotype of c-Myb mutant mice was also assessed. In the mouse, c-Myb expression was detected throughout prenatal development of the first molar tooth. Negative temporospatial correlation was found between c-Myb expression and apoptosis, while c-Myb expression positively correlated with proliferation. c-Myb-positive cells, however, were more abundant than the proliferating cell nuclear antigen positive cells, suggesting other roles of c-Myb in odontogenesis. In the minipig, in contrast to the mouse, there was an asymmetrical arrangement of c-Myb positive cells, with a higher presence on the labial side of the tooth germ and dental lamina. A cluster of negative cells was situated in the mesenchyme close to the tooth bud. At later stages, the number of positive cells decreased and these cells were situated in the upper part of the dental papilla in the areas of future cusp formation. The expression of c-Myb in both species was strong in the odontoblasts and ameloblasts at the stage of dentin and enamel production suggesting a possible novel role of c-Myb during tooth mineralization.
Collapse
Affiliation(s)
- Eva Matalová
- Institute of Animal Physiology and Genetics, v.v.i., Academy of Sciences of the Czech Republic.
| | | | | | | | | | | | | | | |
Collapse
|
5
|
Abstract
The transcription factor MYB has a key role as a regulator of stem and progenitor cells in the bone marrow, colonic crypts and a neurogenic region of the adult brain. It is in these compartments that a deficit in MYB activity leads to severe or lethal phenotypes. As was predicted from its leukaemogenicity in several animal species, MYB has now been identified as an oncogene that is involved in some human leukaemias. Moreover, recent evidence has strengthened the case that MYB is activated in colon and breast cancer: a block to MYB expression is overcome by mutation of the regulatory machinery in the former disease and by oestrogen receptor-alpha (ERalpha) in the latter.
Collapse
Affiliation(s)
- Robert G Ramsay
- Peter MacCallum Cancer Centre, St Andrew's Place, Melbourne, Victoria 3002, Australia
| | | |
Collapse
|
6
|
Kim SY, Yang YS, Hong KH, Jang KY, Chung MJ, Lee DY, Lee JC, Yi HK, Nam SY, Hwang PH. Adenovirus-mediated expression of dominant negative c-myb induces apoptosis in head and neck cancer cells and inhibits tumor growth in animal model. Oral Oncol 2007; 44:383-92. [PMID: 17690006 DOI: 10.1016/j.oraloncology.2007.05.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Revised: 05/04/2007] [Accepted: 05/06/2007] [Indexed: 12/24/2022]
Abstract
The recent demonstration of aberrant expression of the c-myb proto-oncogene in various cancers suggests that c-myb plays an important role in the development of cancer. On this basis, it has been proposed that ablation of c-myb function might be an effective approach for therapy of c-myb dependent malignancies. We previously used a dominant negative c-myb (DN-myb) construct to induce apoptosis in K562 cells. In this study, DN-myb was expressed in an adenovirus-mediated gene delivery system and introduced into head and neck squamous cell carcinoma cells (HNSCC) in vitro and in vivo to examine its tumor suppressive function and its potential in HNSCC gene therapy. Over expression of DN-myb in HNSCC cells inhibited in vitro cell proliferation, expression of growth factors such as IGF-I, -II, IGF-1R, and VEGF, inhibited Akt/PKB pathway activation, and enhanced induction of apoptosis. Similarly, in vivo administration of DN-myb retarded tumor-growth. Our results support a role for DN-myb in inducing apoptosis and tumor suppression, and, furthermore, suggest that DN-myb gene therapy might provide a powerful tool for treatment of c-myb dependent malignancies such as HNSCC.
Collapse
Affiliation(s)
- Sun Young Kim
- Department of Otolaryngology, Chonbuk National University Medical School, Jeonju, Republic of Korea
| | | | | | | | | | | | | | | | | | | |
Collapse
|
7
|
Kopecki Z, Luchetti MM, Adams DH, Strudwick X, Mantamadiotis T, Stoppacciaro A, Gabrielli A, Ramsay RG, Cowin AJ. Collagen loss and impaired wound healing is associated with c-Myb deficiency. J Pathol 2007; 211:351-61. [PMID: 17152050 DOI: 10.1002/path.2113] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Collagen type I serves as an abundant structural and signalling component of skin. It is also an established target gene of the transcription factor, c-Myb. When c-myb-/- embryos were examined it was observed that their skin was markedly thinner than normal. Importantly, immunohistochemical investigation showed complete absence of collagen type I. Although these homozygous knock-out embryos fail to develop beyond day 15, fibroblasts established from these embryos (mouse embryonic fibroblasts [MEFs]) show defective proliferative responses. Furthermore, in vitro scratch wound assays demonstrated that these c-myb-/- MEFs also exhibit slower closure than their wild-type counterparts. Embryonic lethality has meant that examination of the role of c-Myb in adult mouse skin has not been reported to date. However, in view of the abundance of collagen type I in normal skin, its role in skin integrity and the in vitro data showing proliferative and migration defects in c-myb-/- MEFs, we investigated the consequences of heterozygous c-myb loss in adult mice on the complex process of skin repair in response to injury. Our studies clearly demonstrate that heterozygous c-myb deficiency has a functional effect on wound repair, collagen type I levels and, in response to wounding, transforming growth factor-beta1 (an important collagen stimulating factor) induction expression is aberrantly high. Manipulation of c-Myb may therefore provide new therapeutic opportunities for improving wound repair while uncontrolled expression may underpin some fibrotic disorders.
Collapse
Affiliation(s)
- Z Kopecki
- Child Health Research Institute, North Adelaide, South Australia and School of Pharmacy and Medical Sciences, University of South Australia, Australia
| | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Affiliation(s)
- Robert G Ramsay
- Differentiation and Transcription Group, Trescowthick Laboratories, Peter MacCallum Cancer Institute, Victoria, and the University of Melbourne, Department of Pathology, Parkville, Australia.
| |
Collapse
|
9
|
Afroze T, Yang LL, Wang C, Gros R, Kalair W, Hoque AN, Mungrue IN, Zhu Z, Husain M. Calcineurin-independent regulation of plasma membrane Ca2+ ATPase-4 in the vascular smooth muscle cell cycle. Am J Physiol Cell Physiol 2003; 285:C88-95. [PMID: 12660151 DOI: 10.1152/ajpcell.00518.2002] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Calcineurin mediates repression of plasma membrane Ca2+-ATPase-4 (PMCA4) expression in neurons, whereas c-Myb is known to repress PMCA1 expression in vascular smooth muscle cells (VSMC). Here, we describe a novel mouse VSMC line (MOVAS) in which 45Ca efflux rates decreased 50%, fura 2-AM-based intracellular Ca2+ concentrations ([Ca2+]i) increased twofold, and real-time RT-PCR and Western blot revealed a approximately 40% decrease in PMCA4 expression levels from G0 to G1/S in the cell cycle, where PMCA4 constituted approximately 20% of total PMCA protein. Although calcineurin activity increased fivefold as MOVAS progressed from G0 to G1/S, inhibition of this increase with either BAPTA or retroviral transduction with peptide inhibitors of calcineurin (CAIN), or its downstream target nuclear factor of activated T cells (NFAT) (VIVIT), had no effect on the repression of PMCA4 mRNA expression at G1/S. By contrast, Ca2+-independent activity of the calmodulin-dependent protein kinase-II (CaMK-II) increased eightfold as MOVAS progressed from G0 to G1/S, and treatment with an inhibitor of CaMK-II (KN-93) or transduction of a c-Myb-neutralizing antibody significantly alleviated the G1/S-associated repression of PMCA4. These data show that G1/S-specific PMCA4 repression in proliferating VSMC is brought about by c-Myb and CaMK-II and that calcineurin may regulate cell cycle-associated [Ca2+]i through alternate targets.
Collapse
Affiliation(s)
- Talat Afroze
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada M5G-2C4
| | | | | | | | | | | | | | | | | |
Collapse
|
10
|
You XM, Mungrue IN, Kalair W, Afroze T, Ravi B, Sadi AM, Gros R, Husain M. Conditional expression of a dominant-negative c-Myb in vascular smooth muscle cells inhibits arterial remodeling after injury. Circ Res 2003; 92:314-21. [PMID: 12595344 DOI: 10.1161/01.res.0000056758.73215.5a] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Inhibiting activity of the c-Myb transcription factor attenuates G1 to S phase cell cycle transitions in vascular smooth muscle cells (SMCs) in vitro. To determine the effects of arterial SMC-specific expression of a dominant-negative c-Myb molecule (Myb-Engrailed) on vascular remodeling in vivo, we performed carotid artery wire-denudation in 2 independent lines of binary transgenic mice with SM22alpha promoter-defined Doxycycline-suppressible expression of Myb-Engrailed. Adult mice with arterial SMC-specific expression of Myb-Engrailed were overtly normal in appearance and did not display any changes in cardiovascular structure or physiology. However, bromodeoxyuridine-defined arterial SMC proliferation, neointima formation, medial hyperplasia, and arterial remodeling were markedly decreased in mice expressing arterial SMC-restricted Myb-Engrailed after arterial injury. These data suggest that c-Myb activity in arterial SMCs is not essential for arterial structure or function during development, but is involved in the proliferation of arterial SMCs as occurs in vascular pathology, and that the expression of a dominant-negative c-Myb can dramatically reduce adverse arterial remodeling in an in vivo model of restenosis. As such, this model represents a novel tissue-specific strategy for the potential gene therapy of diseases characterized by arterial SMC proliferation.
Collapse
MESH Headings
- Animals
- Bromodeoxyuridine
- Carotid Stenosis/pathology
- Carotid Stenosis/prevention & control
- Cell Division/genetics
- Disease Models, Animal
- Gene Expression/drug effects
- Genes, Dominant
- Homeodomain Proteins/genetics
- Mice
- Mice, Transgenic
- Microfilament Proteins/genetics
- Muscle Proteins/genetics
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Promoter Regions, Genetic
- Proto-Oncogene Proteins c-myb/biosynthesis
- Proto-Oncogene Proteins c-myb/genetics
- Proto-Oncogene Proteins c-myb/pharmacology
- Tetracycline/pharmacology
- Transcription Factors
- Tunica Intima/drug effects
- Tunica Intima/metabolism
- Tunica Intima/pathology
Collapse
Affiliation(s)
- Xiao-Mang You
- Division of Cellular and Molecular Biology, The Toronto General Hospital Research Institute, Ontario, Canada
| | | | | | | | | | | | | | | |
Collapse
|
11
|
Luchetti MM, Paroncini P, Majlingovà P, Frampton J, Mucenski M, Baroni SS, Sambo P, Golay J, Introna M, Gabrielli A. Characterization of the c-Myb-responsive region and regulation of the human type I collagen alpha 2 chain gene by c-Myb. J Biol Chem 2003; 278:1533-41. [PMID: 12424255 DOI: 10.1074/jbc.m204392200] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have characterized the role of c-Myb and B-Myb in the regulation of human type I collagen alpha2 chain gene expression in fibroblastic cells. We have identified four Myb-binding sites (MBSs) in the promoter. Transactivation assays on wild type and mutant promoter-reporter constructs demonstrated that c-Myb, but not B-Myb, can transactivate the human type I collagen alpha 2 chain gene promoter via the MBS-containing region. Electrophoretic mobility shift assay experiments showed that c-Myb specifically binds to each of the four MBS; however, the mutagenesis of site MBS-4 completely inhibited transactivation by c-Myb, at least in the full-length promoter. In agreement with these results, c-myb(-/-) mouse embryo fibroblasts (MEFs) showed a selective lack of expression of type I collagen alpha 2 chain gene but maintained the expression of fibronectin and type III collagen. Furthermore, transforming growth factor-beta induced type I collagen alpha 2 chain gene expression in c-myb(-/-) MEFs, implying that the transforming growth factor-beta signaling pathway is maintained and that the absence of COL1A2 gene expression in c-myb(-/-) MEFs is a direct consequence of the lack of c-Myb. The demonstration of the importance of c-Myb in the regulation of the type I collagen alpha 2 chain gene suggests that uncontrolled expression of c-Myb could be an underlying mechanism in the pathogenesis of several fibrotic disorders.
Collapse
Affiliation(s)
- Michele M Luchetti
- Laboratorio di Medicina Molecolare, Istituto di Clinica Medica, Ematologia ed Immunologia Clinica, Università di Ancona, 60020 Ancona, Italy.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Masuoka HC, Townes TM. Targeted disruption of the activating transcription factor 4 gene results in severe fetal anemia in mice. Blood 2002; 99:736-45. [PMID: 11806972 DOI: 10.1182/blood.v99.3.736] [Citation(s) in RCA: 174] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Activating transcription factor (ATF) 4 is a ubiquitous basic leucine-zipper transcription factor that is a member of the ATF/cyclic adenosine monophosphate responsive element-binding (CREB) protein family. To determine the in vivo function of ATF4, the ATF4 gene in murine embryonic stem cells was deleted and homozygous mutant mice were generated. ATF4 null fetuses were severely anemic because of an impairment in fetal-liver definitive hematopoiesis; the hematocrit in 15.5-day mutant fetuses was 0.15, whereas that in controls was 0.35. The fetal livers in homozygous ATF4 mutants were pale and hypoplastic. In vitro culture of fetal-liver cells showed fewer hematopoietic progenitors per embryo and a dramatic decrease in the size of progenitor colonies. Culture of primary murine embryonic fibroblasts showed a proliferative defect. These results suggest that ATF4 is critical, in a cell-autonomous manner, for normal cellular proliferation, especially for the high-level proliferation required during fetal-liver hematopoiesis.
Collapse
Affiliation(s)
- Howard C Masuoka
- Department of Biochemistry, University of Alabama at Birmingham, 720 20th St S, Birmingham, AL 35294, USA
| | | |
Collapse
|
13
|
Abstract
Syndecan-4, a member of the syndecan gene family of proteoglycans, is an important regulator of bFGF signaling. In particular, bFGF-dependent regulation of cell growth and migration has been linked to syndecan-4 cytoplasmic domain-mediated interactions. Screening of a yeast two-hybrid library with a cytoplasmic domain of rat syndecan-4 identified a novel binding partner, here termed synectin. Synectin is highly homologous to semaphorin F binding protein semcap1, glucose 1 transporter binding protein glut1cbp, and RGS-GAIP/neuropilin-1 binding protein GIPC. Overexpression of synectin in ECV304 cells in culture led to a dose-dependent inhibition of migration while not affecting cell adhesion or growth rate. We conclude that synectin is involved in syndecan-4-dependent interactions and may play a role in the assembly of syndecan-4 signaling complex.
Collapse
Affiliation(s)
- Y Gao
- Angiogenesis Research Center, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | | | | | | |
Collapse
|
14
|
Afroze T, Husain M. c-Myb-binding sites mediate G(1)/S-associated repression of the plasma membrane Ca(2+)-ATPase-1 promoter. J Biol Chem 2000; 275:9062-9. [PMID: 10722757 DOI: 10.1074/jbc.275.12.9062] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
We demonstrate that two Myb-binding sites of the mouse plasma membrane Ca(2+)-ATPase-1 (PMCA1) promoter are required for G(1)/S cell cycle stage-associated repression of PMCA1 promoter activity. Nuclear run-on experiments revealed G(1)/S-associated repression of PMCA1 transcription. Ribonuclease protection assays revealed two transcription initiation sites between two Myb-binding sites in the PMCA1 promoter. Gel shift assays showed that c-Myb can bind to wild-type but not point mutated Myb binding sequences of the PMCA1 promoter. Transient transfection assays using cell cycle-synchronized vascular smooth muscle cells (VSMC) and PMCA1 promoter-luciferase constructs showed a 2-fold decrease in reporter activity at G(1)/S as compared with G(0). Overexpression of wild-type c-Myb severely repressed PMCA1 promoter activity at both G(0) and G(1)/S while co-transfection of a dominant negative c-Myb, or a construct encoding an anti-c-Myb neutralizing antibody, completely abolished the repression seen at G(1)/S. Single nucleotide substitutions in the first, second, or both Myb-binding sites alleviated the G(1)/S-associated repression of PMCA1 promoter activity in transformed rat VSMC and primary mouse VSMC cultures. We conclude that c-Myb mediates G(1)/S-associated transcriptional repression of the PMCA1 Ca(2+) pump in rodent VSMC by direct binding to the PMCA1 promoter.
Collapse
Affiliation(s)
- T Afroze
- Centre for Cardiovascular Research, Toronto General Hospital, Toronto, Ontario, Canada
| | | |
Collapse
|
15
|
Li J, Post M, Volk R, Gao Y, Li M, Metais C, Sato K, Tsai J, Aird W, Rosenberg RD, Hampton TG, Sellke F, Carmeliet P, Simons M. PR39, a peptide regulator of angiogenesis. Nat Med 2000; 6:49-55. [PMID: 10613823 DOI: 10.1038/71527] [Citation(s) in RCA: 296] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Although tissue injury and inflammation are considered essential for the induction of angiogenesis, the molecular controls of this cascade are mostly unknown. Here we show that a macrophage-derived peptide, PR39, inhibited the ubiquitin-proteasome-dependent degradation of hypoxia-inducible factor-1alpha protein, resulting in accelerated formation of vascular structures in vitro and increased myocardial vasculature in mice. For the latter, coronary flow studies demonstrated that PR39-induced angiogenesis resulted in the production of functional blood vessels. These findings show that PR39 and related compounds can be used as potent inductors of angiogenesis, and that selective inhibition of hypoxia-inducible factor-1alpha degradation may underlie the mechanism of inflammation-induced angiogenesis.
Collapse
Affiliation(s)
- J Li
- Angiogenesis Research Center Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Volk R, Schwartz JJ, Li J, Rosenberg RD, Simons M. The role of syndecan cytoplasmic domain in basic fibroblast growth factor-dependent signal transduction. J Biol Chem 1999; 274:24417-24. [PMID: 10446222 DOI: 10.1074/jbc.274.34.24417] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
To determine the role played by syndecan-4 cytoplasmic domain in the mediation of basic fibroblast growth factor (bFGF) signaling, immortalized human cells (ECV) were used to generate cell lines expressing constructs encoding full-length sequences for syndecan-4 (S4), syndecan-1 (S1), glypican-1 (G1), or chimeric proteins consisting of the ectoplasmic domain of glypican-1 linked to the transmembrane/cytoplasmic domain of syndecan-4 (G1-S4c) and the ectoplasmic domain of syndecan-4 linked to the glypican-1 glycosylphosphatidylinositol (GPI) anchor sequence (S4-GPI). Vector-transduced cells (VC) were used as controls. Expression of all these proteoglycans (except for the vector control) significantly increased cell-associated heparan sulfate mass and the number of low affinity bFGF-binding sites. However, in low serum medium, the addition of bFGF stimulated growth and migration of cells expressing S4 and G1-S4c constructs but not G1, S1, S4-GPI, or VC cells. Similar results were obtained using Matrigel growth assays. Mutations of heparan sulfate attachment sites on S4 construct abolished syndecan-4-dependent augmentation of bFGF responses. We conclude that cytoplasmic tail of syndecan-4 plays an important role in bFGF-mediated signal transduction.
Collapse
Affiliation(s)
- R Volk
- Angiogenesis Research Center, Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA
| | | | | | | | | |
Collapse
|
17
|
Bein K, Ware JA, Simons M. Myb-dependent regulation of thrombospondin 2 expression. Role of mRNA stability. J Biol Chem 1998; 273:21423-9. [PMID: 9694906 DOI: 10.1074/jbc.273.33.21423] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The nuclear transcription factor c-Myb, which is highly expressed in hematopoietic cells, has been shown to be functional in NIH 3T3 cells: cells that do not possess detectable levels of c-Myb. To identify endogenous target genes of c-Myb in fibroblasts, RNA isolated from NIH 3T3 cells stably transfected with a full-length or a dominant negative c-myb construct (GREMyb and GREMEn, respectively) was subjected to differential display analysis. 5'-Rapid amplification of cDNA ends of a selected band, sequencing, and a nucleotide homology search led to the identification of thrombospondin 2 (TSP 2) as the gene product repressed in GREMyb and induced in GREMEn cells. The pattern of TSP 2 expression during the cell cycle was consistent with c-myb-dependent regulation. The possibility that the identified transcript was TSP 1, a homologous product known to be repressed by v-Src, c-Jun, and v-Myc, was ruled out by using a TSP 2-specific DNA probe and by showing a distinct pattern of regulation of TSP 1 and TSP 2 expression. Nuclear run-on and TSP 2 promoter-reporter (chloramphenicol acetyltransferase) assays showed similar transcriptional levels in GREMyb and NIH 3T3 cells. However, mRNA stability studies showed a much shorter TSP 2 mRNA half-life in GREMyb compared with wild type NIH 3T3 cells, suggesting that c-myb affects TSP 2 expression via a post-transcriptional mechanism. The implications of a protooncogene-mediated suppression of TSP expression are discussed.
Collapse
Affiliation(s)
- K Bein
- Angiogenesis Research Center, Cardiovascular Division, Department of Medicine Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA
| | | | | |
Collapse
|