701
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Kong W, He L, Coppola M, Guo J, Esposito NN, Coppola D, Cheng JQ. MicroRNA-155 regulates cell survival, growth, and chemosensitivity by targeting FOXO3a in breast cancer. J Biol Chem 2010; 285:17869-79. [PMID: 20371610 DOI: 10.1074/jbc.m110.101055] [Citation(s) in RCA: 276] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Breast cancer is the second leading cause of cancer death in women. Despite improvement in treatment over the past few decades, there is an urgent need for development of targeted therapies. miR-155 (microRNA-155) is frequently up-regulated in breast cancer. In this study, we demonstrate the critical role of miR-155 in regulation of cell survival and chemosensitivity through down-regulation of FOXO3a in breast cancer. Ectopic expression of miR-155 induces cell survival and chemoresistance to multiple agents, whereas knockdown of miR-155 renders cells to apoptosis and enhances chemosensitivity. Further, we identified FOXO3a as a direct target of miR-155. Sustained overexpression of miR-155 resulted in repression of FOXO3a protein without changing mRNA levels, and knockdown of miR-155 increases FOXO3a. Introduction of FOXO3a cDNA lacking the 3'-untranslated region abrogates miR-155-induced cell survival and chemoresistance. Finally, inverse correlation between miR-155 and FOXO3a levels were observed in a panel of breast cancer cell lines and tumors. In conclusion, our study reveals a molecular link between miR-155 and FOXO3a and presents evidence that miR-155 is a critical therapeutic target in breast cancer.
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Affiliation(s)
- William Kong
- Department of Molecular Oncology, H Lee Moffitt Cancer Center, Tampa, Florida 33612, USA
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702
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Khatri S, Yepiskoposyan H, Gallo CA, Tandon P, Plas DR. FOXO3a regulates glycolysis via transcriptional control of tumor suppressor TSC1. J Biol Chem 2010; 285:15960-5. [PMID: 20371605 DOI: 10.1074/jbc.m110.121871] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Akt signal transduction induces coordinated increases in glycolysis and apoptosis resistance in a broad spectrum of cancers. Downstream of Akt, the FoxO transcription factors regulate apoptosis via Bim, but the contributions of FoxOs in regulating Akt-induced glycolysis are not well described. We find that FoxO3a knockdown is sufficient to induce apoptosis resistance in conjunction with elevated glycolysis. Glycolysis in FoxO3a-deficient cells was associated with increased S6K1 phosphorylation and was sensitive to rapamycin, an inhibitor of the mTORC1 pathway that has been linked to glycolysis regulation. We show that mTORC1-dependent glycolysis is increased in FoxO3a knockdown cells due to decreased expression of the TSC1 tumor suppressor that opposes mTORC1 activation. FoxO3a binds to and transactivates the TSC1 promoter, indicating a key role for FoxO3a in regulating TSC1 expression. Together, these data demonstrate that FoxO3a regulates glycolysis downstream of Akt through transcriptional control of Tsc1.
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Affiliation(s)
- Shikha Khatri
- Department of Cancer and Cell Biology, University of Cincinnati, Cincinnati, Ohio 45267, USA
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703
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Guarani V, Potente M. SIRT1 — a metabolic sensor that controls blood vessel growth. Curr Opin Pharmacol 2010; 10:139-45. [DOI: 10.1016/j.coph.2010.01.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Revised: 01/01/2010] [Accepted: 01/14/2010] [Indexed: 01/10/2023]
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704
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Abstract
The classical view of ovarian follicle development is that it is regulated by the hypothalamic-pituitary-ovarian axis, in which gonadotropin-releasing hormone (GnRH) controls the release of the gonadotropic hormones follicle-stimulating hormone (FSH) and luteinizing hormone (LH), and that ovarian steroids exert both negative and positive regulatory effects on GnRH secretion. More recent studies in mice and humans indicate that many other intra-ovarian signaling cascades affect follicular development and gonadotropin action in a stage- and context-specific manner. As we discuss here, mutant mouse models and clinical evidence indicate that some of the most powerful intra-ovarian regulators of follicular development include the TGF-beta/SMAD, WNT/FZD/beta-catenin, and RAS/ERK1/2 signaling pathways and the FOXO/FOXL2 transcription factors.
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Affiliation(s)
- JoAnne S. Richards
- Department of Molecular and Cellular Biology and
Department of Pathology, Baylor College of Medicine, Houston, Texas
| | - Stephanie A. Pangas
- Department of Molecular and Cellular Biology and
Department of Pathology, Baylor College of Medicine, Houston, Texas
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705
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Haigis MC, Sinclair DA. Mammalian sirtuins: biological insights and disease relevance. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2010; 5:253-95. [PMID: 20078221 DOI: 10.1146/annurev.pathol.4.110807.092250] [Citation(s) in RCA: 1569] [Impact Index Per Article: 112.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Aging is accompanied by a decline in the healthy function of multiple organ systems, leading to increased incidence and mortality from diseases such as type II diabetes mellitus, neurodegenerative diseases, cancer, and cardiovascular disease. Historically, researchers have focused on investigating individual pathways in isolated organs as a strategy to identify the root cause of a disease, with hopes of designing better drugs. Studies of aging in yeast led to the discovery of a family of conserved enzymes known as the sirtuins, which affect multiple pathways that increase the life span and the overall health of organisms. Since the discovery of the first known mammalian sirtuin, SIRT1, 10 years ago, there have been major advances in our understanding of the enzymology of sirtuins, their regulation, and their ability to broadly improve mammalian physiology and health span. This review summarizes and discusses the advances of the past decade and the challenges that will confront the field in the coming years.
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Affiliation(s)
- Marcia C Haigis
- Glenn Laboratories for the Molecular Biology of Aging, Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA.
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706
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WU Q, XI JF, LI YL, PEI XT. Progress of Differentiating Human Embryonic Stem Cells Into Endothelial Progenitor Cells and Potential Applications*. PROG BIOCHEM BIOPHYS 2010. [DOI: 10.3724/sp.j.1206.2009.00474] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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707
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Kornblau SM, Singh N, Qiu Y, Chen W, Zhang N, Coombes KR. Highly phosphorylated FOXO3A is an adverse prognostic factor in acute myeloid leukemia. Clin Cancer Res 2010; 16:1865-74. [PMID: 20215543 PMCID: PMC3385949 DOI: 10.1158/1078-0432.ccr-09-2551] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
PURPOSE The Forkhead transcription factors (FOXO) are tumor suppressor genes regulating differentiation, metabolism, and apoptosis that functionally interact with signal transduction pathways shown to be deregulated and prognostic in acute myelogenous leukemia (AML). This study evaluated the level of expression and the prognostic relevance of total and phosphorylated FOXO3A protein in AML. EXPERIMENTAL DESIGN We used reverse-phase protein array methods to measure the level of total and phosphoprotein expression of FOXO3A, in leukemia-enriched protein samples from 511 newly diagnosed AML patients. RESULTS The expression range was similar to normal CD34+ cells and similar in blood and marrow. Levels of total FOXO3A were higher at relapse compared with diagnosis. Levels of pFOXO3A or the ratio of phospho to total (PT) were not associated with karyotpe but were higher in patients with FLT3 mutations. Higher levels of pFOXO3A or PT-FOXO3A were associated with increased proliferation evidenced by strong correlation with higher WBC, percent marrow, and blood blasts and by correlation with higher levels of Cyclins B1, D1 and D3, pGSK3, pMTOR, and pStat5. Patients with High levels of pFOXO3A or PT-FOXO3A had higher rates of primary resistance and shorter remission durations, which combine to cause an inferior survival experience (P = 0.0002). This effect was independent of cytogenetics. PT-FOXO3A was a statistically significant independent predictor in multivariate analysis. CONCLUSIONS High levels of phosphorylation of FOXO3A is a therapeutically targetable, independent adverse prognostic factor in AML.
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MESH Headings
- Adolescent
- Adult
- Aged
- Antigens, CD34/metabolism
- Drug Resistance, Neoplasm
- Female
- Forkhead Box Protein O3
- Forkhead Transcription Factors/metabolism
- Humans
- Leukemia, Myeloid, Acute/metabolism
- Leukemia, Myeloid, Acute/pathology
- Leukemia, Myeloid, Acute/therapy
- Leukemia, Promyelocytic, Acute/metabolism
- Leukemia, Promyelocytic, Acute/pathology
- Leukemia, Promyelocytic, Acute/therapy
- Male
- Middle Aged
- Neoplasm Proteins/metabolism
- Phosphorylation
- Prognosis
- Protein Array Analysis
- Remission Induction
- Survival Rate
- Young Adult
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Affiliation(s)
- Steven M Kornblau
- Departments of Stem Cell Transplantation and Cellular Therapy and Bioinformatics and Computational Biology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030-4095, USA.
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708
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Zanella F, Renner O, García B, Callejas S, Dopazo A, Peregrina S, Carnero A, Link W. Human TRIB2 is a repressor of FOXO that contributes to the malignant phenotype of melanoma cells. Oncogene 2010; 29:2973-82. [PMID: 20208562 DOI: 10.1038/onc.2010.58] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
FOXO transcription factors are evolutionarily conserved proteins that orchestrate gene expression programs known to control a variety of cellular processes such as cell cycle, apoptosis, DNA repair and protection from oxidative stress. As the abrogation of FOXO function is a key feature of many tumor cells, regulation of FOXO factors is receiving increasing attention in cancer research. In order to discover genes involved in the regulation of FOXO activity, we performed a large-scale RNA-mediated interference (RNAi) screen using cell-based reporter systems that monitor transcriptional activity and subcellular localization of FOXO. We identified genes previously implicated in phosphoinositide 3-kinase/Akt signaling events, which are known to be important for FOXO function. In addition, we discovered a previously unrecognized FOXO-repressor function of TRIB2, the mammalian homolog of the Drosophila gene tribbles. A cancer-profiling array revealed specific overexpression of TRIB2 in malignant melanoma, but not in other types of skin cancer. We provide experimental evidence that TRIB2 transcript levels correlate with the degree of cytoplasmic localization of FOXO3a. Moreover, we show that TRIB2 is important in the maintenance of the oncogenic properties of melanoma cells, as its silencing reduces cell proliferation, colony formation and wound healing. Tumor growth was also substantially reduced upon RNAi-mediated TRIB2 knockdown in an in vivo melanoma xenograft model. Our studies suggest that TRIB2 provides the melanoma cells with growth and survival advantages through the abrogation of FOXO function. Altogether, our results show the potential of large-scale cell-based RNAi screens to identify promising diagnostic markers and therapeutic targets.
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Affiliation(s)
- F Zanella
- Experimental Therapeutics Program, Centro Nacional de Investigaciones Oncologicas (CNIO), Madrid 28029, Spain
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709
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Abstract
Maintaining stem cell quiescence is intimately connected to preserving long-term self-renewal potential. In this issue of Cell Stem Cell,Paik et al. (2009) and Renault et al. (2009) demonstrate a role for FoxO transcription factors in regulating neural stem cell proliferation and in maintaining stem and progenitor cell homeostasis.
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Affiliation(s)
- Edmund Chen
- Translational Medicine Branch, National Heart Lung and Blood Institute, NIH, Bethesda, MD 20892, USA
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710
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Paik JH, Ding Z, Narurkar R, Ramkissoon S, Muller F, Kamoun WS, Chae SS, Zheng H, Ying H, Mahoney J, Hiller D, Jiang S, Protopopov A, Wong WH, Chin L, Ligon KL, DePinho RA. FoxOs cooperatively regulate diverse pathways governing neural stem cell homeostasis. Cell Stem Cell 2010; 5:540-53. [PMID: 19896444 DOI: 10.1016/j.stem.2009.09.013] [Citation(s) in RCA: 352] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Revised: 07/01/2009] [Accepted: 09/28/2009] [Indexed: 10/20/2022]
Abstract
The PI3K-AKT-FoxO pathway is integral to lifespan regulation in lower organisms and essential for the stability of long-lived cells in mammals. Here, we report the impact of combined FoxO1, 3, and 4 deficiencies on mammalian brain physiology with a particular emphasis on the study of the neural stem/progenitor cell (NSC) pool. We show that the FoxO family plays a prominent role in NSC proliferation and renewal. FoxO-deficient mice show initial increased brain size and proliferation of neural progenitor cells during early postnatal life, followed by precocious significant decline in the NSC pool and accompanying neurogenesis in adult brains. Mechanistically, integrated transcriptomic, promoter, and functional analyses of FoxO-deficient NSC cultures identified direct gene targets with known links to the regulation of human brain size and the control of cellular proliferation, differentiation, and oxidative defense. Thus, the FoxO family coordinately regulates diverse genes and pathways to govern key aspects of NSC homeostasis in the mammalian brain.
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Affiliation(s)
- Ji-hye Paik
- Department of Medical Oncology, Belfer Institute for Applied Cancer Science, Harvard Medical School, Boston, MA 02115, USA
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711
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Renault VM, Rafalski VA, Morgan AA, Salih DAM, Brett JO, Webb AE, Villeda SA, Thekkat PU, Guillerey C, Denko NC, Palmer TD, Butte AJ, Brunet A. FoxO3 regulates neural stem cell homeostasis. Cell Stem Cell 2010; 5:527-39. [PMID: 19896443 DOI: 10.1016/j.stem.2009.09.014] [Citation(s) in RCA: 438] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2008] [Revised: 06/26/2009] [Accepted: 09/28/2009] [Indexed: 02/08/2023]
Abstract
In the nervous system, neural stem cells (NSCs) are necessary for the generation of new neurons and for cognitive function. Here we show that FoxO3, a member of a transcription factor family known to extend lifespan in invertebrates, regulates the NSC pool. We find that adult FoxO3(-/-) mice have fewer NSCs in vivo than wild-type counterparts. NSCs isolated from adult FoxO3(-/-) mice have decreased self-renewal and an impaired ability to generate different neural lineages. Identification of the FoxO3-dependent gene expression profile in NSCs suggests that FoxO3 regulates the NSC pool by inducing a program of genes that preserves quiescence, prevents premature differentiation, and controls oxygen metabolism. The ability of FoxO3 to prevent the premature depletion of NSCs might have important implications for counteracting brain aging in long-lived species.
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712
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Latré de Laté P, Pépin A, Assaf-Vandecasteele H, Espinasse C, Nicolas V, Asselin-Labat ML, Bertoglio J, Pallardy M, Biola-Vidamment A. Glucocorticoid-induced leucine zipper (GILZ) promotes the nuclear exclusion of FOXO3 in a Crm1-dependent manner. J Biol Chem 2010; 285:5594-605. [PMID: 20018851 PMCID: PMC2820786 DOI: 10.1074/jbc.m109.068346] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Revised: 12/03/2009] [Indexed: 12/14/2022] Open
Abstract
GILZ (glucocorticoid-induced leucine zipper) is an ubiquitous protein whose expression is induced by glucocorticoids in lymphoid cells. We previously showed that GILZ expression is rapidly induced upon interleukin 2 deprivation in T-cells, protecting cells from apoptosis induced by forkhead box subgroup O3 (FOXO3). The aim of this work is to elucidate the molecular mechanism of FOXO factor inhibition by GILZ. We show in the myeloid cell line HL-60 and the lymphoid CTLL-2 T-cell line that GILZ down-regulates the expression of p27(KIP1) and Bim, two FOXO targets involved in cell cycle regulation and apoptosis, respectively. GILZ inhibits FOXO1, FOXO3, and FOXO4 transcriptional activities measured with natural or synthetic FOXO-responsive promoters in HL-60 cells. This inhibitory effect is independent of protein kinase B and IkappaB kinase phosphorylation sites. GILZ does not hinder FOXO3 DNA-binding activity and does not physically interact with FOXO3. However, using fluorescence microscopy, we observe that GILZ expression provokes a Crm-1-dependent nuclear exclusion of FOXO3 leading to its relocalization to the cytoplasm. Moreover, GILZ exclusive cytoplasmic localization is a prerequisite for FOXO3 inhibition and relocalization. We propose that GILZ is a general inhibitor of FOXO factors acting through an original mechanism by preventing them from reaching target genes within the nucleus.
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Affiliation(s)
- Perle Latré de Laté
- From the Université Paris Sud, INSERM UMR-S 749, Faculté de Pharmacie, and INSERM, Université Paris-Sud 11, 92296 Châtenay-Malabry, France and
| | - Aurélie Pépin
- From the Université Paris Sud, INSERM UMR-S 749, Faculté de Pharmacie, and INSERM, Université Paris-Sud 11, 92296 Châtenay-Malabry, France and
| | - Hind Assaf-Vandecasteele
- From the Université Paris Sud, INSERM UMR-S 749, Faculté de Pharmacie, and INSERM, Université Paris-Sud 11, 92296 Châtenay-Malabry, France and
| | - Christophe Espinasse
- From the Université Paris Sud, INSERM UMR-S 749, Faculté de Pharmacie, and INSERM, Université Paris-Sud 11, 92296 Châtenay-Malabry, France and
| | - Valérie Nicolas
- the Plate-Forme Imagerie Cellulaire, IFR141-ITFM, Université Paris-Sud 11, 92296 Châtenay-Malabry, France
| | - Marie-Liesse Asselin-Labat
- From the Université Paris Sud, INSERM UMR-S 749, Faculté de Pharmacie, and INSERM, Université Paris-Sud 11, 92296 Châtenay-Malabry, France and
| | - Jacques Bertoglio
- From the Université Paris Sud, INSERM UMR-S 749, Faculté de Pharmacie, and INSERM, Université Paris-Sud 11, 92296 Châtenay-Malabry, France and
| | - Marc Pallardy
- From the Université Paris Sud, INSERM UMR-S 749, Faculté de Pharmacie, and INSERM, Université Paris-Sud 11, 92296 Châtenay-Malabry, France and
| | - Armelle Biola-Vidamment
- From the Université Paris Sud, INSERM UMR-S 749, Faculté de Pharmacie, and INSERM, Université Paris-Sud 11, 92296 Châtenay-Malabry, France and
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713
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Kaneda H, Arao T, Tanaka K, Tamura D, Aomatsu K, Kudo K, Sakai K, De Velasco MA, Matsumoto K, Fujita Y, Yamada Y, Tsurutani J, Okamoto I, Nakagawa K, Nishio K. FOXQ1 is overexpressed in colorectal cancer and enhances tumorigenicity and tumor growth. Cancer Res 2010; 70:2053-63. [PMID: 20145154 DOI: 10.1158/0008-5472.can-09-2161] [Citation(s) in RCA: 143] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Forkhead box Q1 (FOXQ1) is a member of the forkhead transcription factor family, and it has recently been proposed to participate in gastric acid secretion and mucin gene expression in mice. However, the role of FOXQ1 in humans and especially in cancer cells remains unknown. We found that FOXQ1 mRNA is overexpressed in clinical specimens of colorectal cancer (CRC; 28-fold/colonic mucosa). A microarray analysis revealed that the knockdown of FOXQ1 using small interfering RNA resulted in a decrease in p21(CIP1/WAF1) expression, and a reporter assay and a chromatin immunoprecipitation assay showed that p21 was one of the target genes of FOXQ1. Stable FOXQ1-overexpressing cells (H1299/FOXQ1) exhibited elevated levels of p21 expression and inhibition of apoptosis induced by doxorubicin or camptothecin. Although cellular proliferation was decreased in H1299/FOXQ1 cells in vitro, H1299/FOXQ1 cells significantly increased tumorigenicity [enhanced green fluorescent protein (EGFP): 2/15, FOXQ1: 7/15] and enhanced tumor growth (437 +/- 301 versus 1735 +/- 769 mm3, P < 0.001) in vivo. Meanwhile, stable p21 knockdown of H1299/FOXQ1 cells increased tumor growth, suggesting that FOXQ1 promotes tumor growth independent of p21. Microarray analysis of H1299/EGFP and H1299/FOXQ1 revealed that FOXQ1 overexpression upregulated several genes that have positive roles for tumor growth, including VEGFA, WNT3A, RSPO2, and BCL11A. CD31 and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining of the tumor specimens showed that FOXQ1 overexpression mediated the angiogenic and antiapoptotic effect in vivo. In conclusion, FOXQ1 is overexpressed in CRC and enhances tumorigenicity and tumor growth presumably through its angiogenic and antiapoptotic effects. Our findings show that FOXQ1 is a new member of the cancer-related FOX family.
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Affiliation(s)
- Hiroyasu Kaneda
- Department of Genome Biology, Kinki University School of Medicine, Osaka-Sayama, Osaka, Japan
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714
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Le Lay J, Kaestner KH. The Fox genes in the liver: from organogenesis to functional integration. Physiol Rev 2010; 90:1-22. [PMID: 20086072 DOI: 10.1152/physrev.00018.2009] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Formation and function of the liver are highly controlled, essential processes. Multiple signaling pathways and transcriptional regulatory networks cooperate in this complex system. The evolutionarily conserved FOX, for Forkhead bOX, class of transcriptional regulators is critical to many aspects of liver development and function. The FOX proteins are small, mostly monomeric DNA binding factors containing the so-called winged helix DNA binding motif that distinguishes them from other classes of transcription factors. We discuss the biochemical and genetic roles of Foxa, Foxl1, Foxm1, and Foxo, as these have been shown to regulate many processes throughout the life of the organ, controlling both formation and function of the liver.
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Affiliation(s)
- John Le Lay
- Department of Genetics and Institute for Diabetes, Obesity, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6145, USA
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715
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Rached MT, Kode A, Xu L, Yoshikawa Y, Paik JH, Depinho RA, Kousteni S. FoxO1 is a positive regulator of bone formation by favoring protein synthesis and resistance to oxidative stress in osteoblasts. Cell Metab 2010; 11:147-60. [PMID: 20142102 PMCID: PMC2820405 DOI: 10.1016/j.cmet.2010.01.001] [Citation(s) in RCA: 233] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Revised: 10/23/2009] [Accepted: 01/06/2010] [Indexed: 12/13/2022]
Abstract
Osteoporosis, a disease of low bone mass, is associated with decreased osteoblast numbers and increased levels of oxidative stress within osteoblasts. Since transcription factors of the FoxO family confer stress resistance, we investigated their potential impact on skeletal integrity. Here we employ cell-specific deletion and molecular analyses to show that, among the three FoxO proteins, only FoxO1 is required for proliferation and redox balance in osteoblasts and thereby controls bone formation. FoxO1 regulation of osteoblast proliferation occurs through its interaction with ATF4, a transcription factor regulating amino acid import, as well as through its regulation of a stress-dependent pathway influencing p53 signaling. Accordingly, decreasing oxidative stress levels or increasing protein intake normalizes bone formation and bone mass in mice lacking FoxO1 specifically in osteoblasts. These results identify FoxO1 as a crucial regulator of osteoblast physiology and provide a direct mechanistic link between oxidative stress and the regulation of bone remodeling.
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Affiliation(s)
- Marie-Therese Rached
- Department of Medicine, Division of Endocrinology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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716
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Ambrogini E, Almeida M, Martin-Millan M, Paik JH, Depinho RA, Han L, Goellner J, Weinstein RS, Jilka RL, O'Brien CA, Manolagas SC. FoxO-mediated defense against oxidative stress in osteoblasts is indispensable for skeletal homeostasis in mice. Cell Metab 2010; 11:136-46. [PMID: 20142101 PMCID: PMC2819984 DOI: 10.1016/j.cmet.2009.12.009] [Citation(s) in RCA: 216] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2009] [Revised: 09/17/2009] [Accepted: 12/18/2009] [Indexed: 01/10/2023]
Abstract
Aging increases oxidative stress and osteoblast apoptosis and decreases bone mass, whereas forkhead box O (FoxO) transcription factors defend against oxidative stress by activating genes involved in free radical scavenging and apoptosis. Conditional deletion of FoxO1, FoxO3, and FoxO4 in 3-month-old mice resulted in an increase in oxidative stress in bone and osteoblast apoptosis and a decrease in the number of osteoblasts, the rate of bone formation, and bone mass at cancellous and cortical sites. The effect of the deletion on osteoblast apoptosis was cell autonomous and resulted from oxidative stress. Conversely, overexpression of a FoxO3 transgene in mature osteoblasts decreased oxidative stress and osteoblast apoptosis and increased osteoblast number, bone formation rate, and vertebral bone mass. We conclude that FoxO-dependent oxidative defense provides a mechanism to handle the oxygen free radicals constantly generated by the aerobic metabolism of osteoblasts and is thereby indispensable for bone mass homeostasis.
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Affiliation(s)
- Elena Ambrogini
- Division of Endocrinology and Metabolism, Center for Osteoporosis and Metabolic Bone Diseases, University of Arkansas for Medical Sciences and the Central Arkansas Veterans Healthcare System, Little Rock, AR 72205, USA
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717
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Czymai T, Viemann D, Sticht C, Molema G, Goebeler M, Schmidt M. FOXO3 modulates endothelial gene expression and function by classical and alternative mechanisms. J Biol Chem 2010; 285:10163-78. [PMID: 20123982 DOI: 10.1074/jbc.m109.056663] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
FOXO transcription factors represent targets of the phosphatidylinositol 3-kinase/protein kinase B survival pathway controlling important biological processes, such as cell cycle progression, apoptosis, vascular remodeling, stress responses, and metabolism. Recent studies suggested the existence of alternative mechanisms of FOXO-dependent gene expression beyond classical binding to a FOXO-responsive DNA-binding element (FRE). Here we analyzed the relative contribution of those mechanisms to vascular function by comparing the transcriptional and cellular responses to conditional activation of FOXO3 and a corresponding FRE-binding mutant in human primary endothelial cells. We demonstrate that FOXO3 controls expression of vascular remodeling genes in an FRE-dependent manner. In contrast, FOXO3-induced cell cycle arrest and apoptosis occurs independently of FRE binding, albeit FRE-dependent gene expression augments the proapoptotic response. These findings are supported by bioinformatical analysis, which revealed a statistical overrepresentation of cell cycle regulators and apoptosis-related genes in the group of co-regulated genes. Molecular analysis of FOXO3-induced endothelial apoptosis excluded modulators of the extrinsic death receptor pathway and demonstrated important roles for the BCL-2 family members BIM and NOXA in this process. Although NOXA essentially contributed to FRE-dependent apoptosis, BIM was effectively induced in the absence of FRE-binding, and small interfering RNA-mediated BIM depletion could rescue apoptosis induced by both FOXO3 mutants. These data suggest BIM as a critical cell type-specific mediator of FOXO3-induced endothelial apoptosis, whereas NOXA functions as an amplifying factor. Our study provides the first comprehensive analysis of alternatively regulated FOXO3 targets in relevant primary cells and underscores the importance of such genes for endothelial function and integrity.
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Affiliation(s)
- Tobias Czymai
- Department of Dermatology, University Medical Center Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany
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718
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Hydrogen peroxide stress stimulates phosphorylation of FoxO1 in rat aortic endothelial cells. Acta Pharmacol Sin 2010; 31:160-4. [PMID: 20139898 DOI: 10.1038/aps.2009.201] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
AIM To examine whether the phosphorylation of the O subfamily of forkhead transcription factors (FoxO) is involved in response to oxidative stress in rat aortic endothelial cells (RAECs). METHODS RAECs were treated with H(2)0(2) and phosphorylation status of proteins were evaluated by Western blot analysis. The subcellular localization of FoxO1 was determined by nuclear and cytosolic fractionation followed by Western blot analysis as well as immunocytochemistry. The transcriptional activity of FoxO1 in H(2)0(2) stress was assessed by luciferase reporter assay. Expression of FoxO1 target gene was determined by real-time PCR analysis. RESULTS H(2)0(2) stress stimulated phosphorylation of FoxO1 at Thr24 and Ser256 in a concentration and time dependent manner in RAECs. Pretreatment of RAECs with PI-3K inhibitors abolished the activation of Akt and prevented the phosphorylation of FoxO1. Akt-mediated phosphorylation promoted nuclear exclusion of FoxO1. An IRS-driven luciferase activity transactivated by exogenous FoxO1 was modestly suppressed by hydrogen peroxide stress. The expression of Bim, a target gene of FoxO factors, was negatively regulated by Akt-mediated phosphorylation in response to hydrogen peroxide stimulation. CONCLUSION Our data demonstrate that phosphorylation of FoxO1 by PI-3K/Akt signaling is implicated in response to oxidative stress in vascular endothelial cells.
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719
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Oxidative stress: Biomarkers and novel therapeutic pathways. Exp Gerontol 2010; 45:217-34. [PMID: 20064603 DOI: 10.1016/j.exger.2010.01.004] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2009] [Revised: 12/28/2009] [Accepted: 01/07/2010] [Indexed: 01/12/2023]
Abstract
Oxidative stress significantly impacts multiple cellular pathways that can lead to the initiation and progression of varied disorders throughout the body. It therefore becomes imperative to elucidate the components and function of novel therapeutic strategies against oxidative stress to further clinical diagnosis and care. In particular, both the growth factor and cytokine erythropoietin (EPO) and members of the mammalian forkhead transcription factors of the O class (FoxOs) may offer the greatest promise for new treatment regimens since these agents and the cellular pathways they oversee cover a range of critical functions that directly influence progenitor cell development, cell survival and degeneration, metabolism, immune function, and cancer cell invasion. Furthermore, both EPO and FoxOs function not only as therapeutic targets, but also as biomarkers of disease onset and progression, since their cellular pathways are closely linked and overlap with several unique signal transduction pathways. However, biological outcome with EPO and FoxOs may sometimes be both unexpected and undesirable that can raise caution for these agents and warrant further investigations. Here we present the exciting as well as complicated role EPO and FoxOs possess to uncover the benefits as well as the risks of these agents for cell biology and clinical care in processes that range from stem cell development to uncontrolled cellular proliferation.
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720
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Abstract
Self-renewal is the process by which stem cells divide to make more stem cells, perpetuating the stem cell pool throughout life. Self-renewal is division with maintenance of the undifferentiated state. This requires cell cycle control and often maintenance of multipotency or pluripotency, depending on the stem cell. Self-renewal programs involve networks that balance proto-oncogenes (promoting self-renewal), gate-keeping tumor suppressors (limiting self-renewal), and care-taking tumor suppressors (maintaining genomic integrity). These cell-intrinsic mechanisms are regulated by cell-extrinsic signals from the niche, the microenvironment that maintains stem cells and regulates their function in tissues. In response to changing tissue demands, stem cells undergo changes in cell cycle status and developmental potential over time, requiring different self-renewal programs at different stages of life. Reduced stem cell function and tissue regenerative capacity during aging are caused by changes in self-renewal programs that augment tumor suppression. Cancer arises from mutations that inappropriately activate self-renewal programs.
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Affiliation(s)
- Shenghui He
- Howard Hughes Medical Institute, Life Sciences Institute, Department of Internal Medicine, Center for Stem Cell Biology, University of Michigan, Ann Arbor, Michigan 48109-2216, USA
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721
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Abstract
Infertility adversely affects many couples worldwide. Conversely, the exponential increase in world population threatens our planet and its resources. Therefore, a greater understanding of the fundamental cellular and molecular events that control the size of the primordial follicle pool and follicular development is of utmost importance to develop improved in vitro fertilization as well as to design novel approaches to regulate fertility. In this review we attempt to highlight some new advances in basic research of the mammalian ovary that have occurred in recent years focusing primarily on mouse models that have contributed to our understanding of ovarian follicle formation, development, and ovulation. We hope that these new insights into ovarian function will trigger more research and translation to clinically relevant problems.
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722
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Reiter CEN, Kim JA, Quon MJ. Green tea polyphenol epigallocatechin gallate reduces endothelin-1 expression and secretion in vascular endothelial cells: roles for AMP-activated protein kinase, Akt, and FOXO1. Endocrinology 2010; 151:103-14. [PMID: 19887561 PMCID: PMC2803145 DOI: 10.1210/en.2009-0997] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Epigallocatechin gallate (EGCG), a green tea polyphenol, promotes vasodilation by phosphatidylinositol 3-kinase-dependent activation of Akt and endothelial nitric oxide synthase to stimulate production of nitric oxide. Reduction in endothelin-1 (ET-1) synthesis may also increase bioavailability of nitric oxide. We hypothesized that the phosphatidylinositol 3-kinase-dependent transcription factor FOXO1 may mediate effects of EGCG to regulate expression of ET-1 in endothelial cells. EGCG treatment (10 microm, 8 h) of human aortic endothelial cells reduced expression of ET-1 mRNA, protein, and ET-1 secretion. We identified a putative FOXO binding domain in the human ET-1 promoter 51 bp upstream from the transcription start site. Trans-activation of a human ET-1 (hET-1) promoter luciferase reporter was enhanced by coexpression of a constitutively nuclear FOXO1 mutant, whereas expression of a mutant FOXO1 with disrupted DNA binding domain did not trans-activate the hET-1 promoter. Disrupting the hET-1 putative FOXO binding domain by site-directed mutagenesis ablated promoter activity in response to overexpression of wild-type FOXO1. EGCG stimulated time-dependent phosphorylation of Akt (S(473)), FOXO1 (at Akt phosphorylation site T(24)), and AMP-activated protein kinase alpha (AMPK alpha) (T(172)). EGCG-induced nuclear exclusion of FOXO1, FOXO1 binding to the hET-1 promoter, and reduction of ET-1 expression was partially inhibited by the AMPK inhibitor Compound C. Basal ET-1 protein expression was enhanced by short interfering RNA knock-down of Akt and reduced by short interfering RNA knock-down of FOXO1 or adenovirus-mediated expression of dominant-negative Foxo1. We conclude that EGCG decreases ET-1 expression and secretion from endothelial cells, in part, via Akt- and AMPK-stimulated FOXO1 regulation of the ET-1 promoter. These findings may be relevant to beneficial cardiovascular actions of green tea.
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Affiliation(s)
- Chad E N Reiter
- Diabetes Unit, National Center for Complementary and Alternative Medicine, National Institutes of Health, 9 Memorial Drive, Bethesda, Maryland 20892-0920, USA
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723
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Blake DC, Mikse OR, Freeman WM, Herzog CR. FOXO3a elicits a pro-apoptotic transcription program and cellular response to human lung carcinogen nicotine-derived nitrosaminoketone (NNK). Lung Cancer 2010; 67:37-47. [DOI: 10.1016/j.lungcan.2009.03.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Revised: 03/12/2009] [Accepted: 03/13/2009] [Indexed: 10/20/2022]
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724
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Samarin J, Wessel J, Cicha I, Kroening S, Warnecke C, Goppelt-Struebe M. FoxO proteins mediate hypoxic induction of connective tissue growth factor in endothelial cells. J Biol Chem 2009; 285:4328-36. [PMID: 20018872 DOI: 10.1074/jbc.m109.049650] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Hypoxia, a driving force in neovascularization, promotes alterations in gene expression mediated by hypoxia-inducible factor (HIF)-1alpha. Connective tissue growth factor (CTGF, CCN2) is a modulator of endothelial cell growth and migration, but its regulation by hypoxia is poorly understood. Therefore, we analyzed signaling pathways involved in the regulation of CTGF by hypoxia in endothelial cells. Exposure to low oxygen tension or treatment with the hypoxia-mimetic dimethyloxalyl glycine (DMOG) stabilized HIF-1alpha and up-regulated CTGF in human umbilical vein endothelial cells and in a murine microvascular endothelial cell line. Induction of CTGF correlated with a HIF-dependent increase in protein and mRNA levels, and nuclear accumulation of the transcription factor FoxO3a. By contrast, gene expression and cellular localization of FoxO1 were not significantly altered by hypoxia. Expression of CTGF was strongly reduced by siRNA silencing of FoxO1 or FoxO3a. Furthermore, nuclear exclusion of FoxO1/3a transcription factors by inhibition of serine/threonine protein phosphatases by okadaic acid inhibited CTGF expression, providing evidence for both FoxO proteins as regulators of CTGF expression. The DMOG-stimulated induction of CTGF was further increased when endothelial cells were co-incubated with transforming growth factor-beta, an activator of Smad signaling. Activation of RhoA-Rho kinase signaling by the microtubule-disrupting drug combretastatin A4 also enhanced the DMOG-induced CTGF expression, thus placing CTGF induction by hypoxia in a network of interacting signaling pathways. Our findings provide evidence that FoxO1, hypoxia-stimulated expression of FoxO3a and its nuclear accumulation are required for the induction of CTGF by hypoxia in endothelial cells.
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Affiliation(s)
- Jana Samarin
- Department of Nephrology and Hypertension, Medical College of Georgia, Augusta, Georgia 30912
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725
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Rached MT, Kode A, Silva BC, Jung DY, Gray S, Ong H, Paik JH, DePinho RA, Kim JK, Karsenty G, Kousteni S. FoxO1 expression in osteoblasts regulates glucose homeostasis through regulation of osteocalcin in mice. J Clin Invest 2009; 120:357-68. [PMID: 20038793 DOI: 10.1172/jci39901] [Citation(s) in RCA: 158] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Accepted: 10/14/2009] [Indexed: 12/13/2022] Open
Abstract
Osteoblasts have recently been found to play a role in regulating glucose metabolism through secretion of osteocalcin. It is unknown, however, how this osteoblast function is regulated transcriptionally. As FoxO1 is a forkhead family transcription factor known to regulate several key aspects of glucose homeostasis, we investigated whether its expression in osteoblasts may contribute to its metabolic functions. Here we show that mice lacking Foxo1 only in osteoblasts had increased pancreatic beta cell proliferation, insulin secretion, and insulin sensitivity. The ability of osteoblast-specific FoxO1 deficiency to affect metabolic homeostasis was due to increased osteocalcin expression and decreased expression of Esp, a gene that encodes a protein responsible for decreasing the bioactivity of osteocalcin. These results indicate that FoxO1 expression in osteoblasts contributes to FoxO1 control of glucose homeostasis and identify FoxO1 as a key modulator of the ability of the skeleton to function as an endocrine organ regulating glucose metabolism.
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Affiliation(s)
- Marie-Therese Rached
- Department of Medicine, Division of Endocrinology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
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726
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Abstract
Human cancers, including acute myeloid leukemia (AML), commonly display constitutive phosphoinositide 3-kinase (PI3K) AKT signaling. However, the exact role of AKT activation in leukemia and its effects on hematopoietic stem cells (HSCs) are poorly understood. Several members of the PI3K pathway, phosphatase and tensin homolog (Pten), the forkhead box, subgroup O (FOXO) transcription factors, and TSC1, have demonstrated functions in normal and leukemic stem cells but are rarely mutated in leukemia. We developed an activated allele of AKT1 that models increased signaling in normal and leukemic stem cells. In our murine bone marrow transplantation model using a myristoylated AKT1 (myr-AKT), recipients develop myeloproliferative disease, T-cell lymphoma, or AML. Analysis of the HSCs in myr-AKT mice reveals transient expansion and increased cycling, associated with impaired engraftment. myr-AKT-expressing bone marrow cells are unable to form cobblestones in long-term cocultures. Rapamycin, an inhibitor of the mammalian target of rapamycin (mTOR) rescues cobblestone formation in myr-AKT-expressing bone marrow cells and increases the survival of myr-AKT mice. This study demonstrates that enhanced AKT activation is an important mechanism of transformation in AML and that HSCs are highly sensitive to excess AKT/mTOR signaling.
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727
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Abstract
Nutrition is a key regulator of tissue growth. In animals, nutritional status is monitored and signaled at both the cellular and systemic levels. The main mediator of cellular nutrient sensing is the protein kinase TOR (target of rapamycin). TOR receives information from levels of cellular amino acids and energy, and it regulates the activity of processes involved in cell growth, such as protein synthesis and autophagy. Insulin-like signaling is the main mechanism of systemic nutrient sensing and mediates its growth-regulatory functions largely through the phosphatidylinositol 3-kinase (PI3K)/AKT protein kinase pathway. Other nutrition-regulated hormonal mechanisms contribute to growth control by modulating the activity of insulin-like signaling. The pathways mediating signals from systemic and cellular levels converge, allowing cells to combine information from both sources. Here we give an overview of the mechanisms that adjust animal tissue growth in response to nutrition and highlight some general features of the signaling pathways involved.
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728
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Srinivasan L, Sasaki Y, Calado DP, Zhang B, Paik JH, DePinho RA, Kutok JL, Kearney JF, Otipoby KL, Rajewsky K. PI3 kinase signals BCR-dependent mature B cell survival. Cell 2009; 139:573-86. [PMID: 19879843 DOI: 10.1016/j.cell.2009.08.041] [Citation(s) in RCA: 520] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2009] [Revised: 07/17/2009] [Accepted: 08/26/2009] [Indexed: 01/01/2023]
Abstract
Previous work has shown that mature B cells depend upon survival signals delivered to the cells by their antigen receptor (BCR). To identify the molecular nature of this survival signal, we have developed a genetic approach in which ablation of the BCR is combined with the activation of specific, BCR dependent signaling cascades in mature B cells in vivo. Using this system, we provide evidence that the survival of BCR deficient mature B cells can be rescued by a single signaling pathway downstream of the BCR, namely PI3K signaling, with the FOXO1 transcription factor playing a central role.
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Affiliation(s)
- Lakshmi Srinivasan
- Program of Cellular and Molecular Medicine, Children's Hospital, and Immune Disease Institute, Harvard Medical School, Boston, MA 02115, USA
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729
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Komorowsky C, Ocker M, Goppelt‐Struebe M. Differential regulation of connective tissue growth factor in renal cells by histone deacetylase inhibitors. J Cell Mol Med 2009. [DOI: 10.1111/j.1582-4934.2008.00674.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Affiliation(s)
| | - Matthias Ocker
- Department of Gastroenterology & Hepatology, University Hospital Erlangen, Erlangen, Germany
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730
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Adding more content to screening: reactivation of FOXO as a therapeutic strategy. Clin Transl Oncol 2009; 11:651-8. [DOI: 10.1007/s12094-009-0420-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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731
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Sugiura K, Su YQ, Li Q, Wigglesworth K, Matzuk MM, Eppig JJ. Fibroblast growth factors and epidermal growth factor cooperate with oocyte-derived members of the TGFbeta superfamily to regulate Spry2 mRNA levels in mouse cumulus cells. Biol Reprod 2009; 81:833-41. [PMID: 19553596 PMCID: PMC2770016 DOI: 10.1095/biolreprod.109.078485] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2009] [Revised: 05/20/2009] [Accepted: 06/14/2009] [Indexed: 11/01/2022] Open
Abstract
Mouse oocytes produce members of the transforming growth factor beta (TGFbeta) superfamily, including bone morphogenetic protein 15 (BMP15) and growth differentiation factor 9 (GDF9), as well as fibroblast growth factors (FGFs). These growth factors cooperate to regulate cumulus cell function. To identify potential mechanisms involved in these interactions, the ability of fully grown oocytes to regulate expression of BMP or FGF antagonists in cumulus cells was examined. Oocytes promoted cumulus cell expression of transcripts encoding antagonists to TGFbeta superfamily members, including Grem2, Htra1, Htra3, and Nog mRNAs. In contrast, oocytes suppressed cumulus cell expression of Spry2 mRNA, which encodes a regulator of receptor tyrosine kinase signals, such as FGF and epidermal growth factor (EGF) receptor signals. The regulation of Spry2 mRNA levels in cumulus cells was studied further as a model for analysis of potential mechanisms for cooperativity of FGF/EGF signaling with oocyte-derived members of the TGFbeta superfamily. Oocytes suppressed basal and FGF-stimulated Spry2 mRNA levels in cumulus cells but promoted EGF-stimulated levels. Furthermore, recombinant TGFbeta superfamily proteins, including BMP15 and GDF9, mimicked these effects of oocytes. Elevated expression of Spry2 mRNA in cumulus and mural granulosa cells correlated with human chorionic gonadotropin-induced expression of mRNAs encoding EGF-like peptides. Therefore, oocyte-derived members of the TGFbeta superfamily suppress FGF-stimulated Spry2 mRNA levels before the luteinizing hormone surge but promote Spry2 mRNA levels stimulated by EGF receptor-mediated signals after the surge.
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Affiliation(s)
- Koji Sugiura
- The Jackson Laboratory, Bar Harbor, Maine 04609, USA.
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732
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Finlay DK, Sinclair LV, Feijoo C, Waugh CM, Hagenbeek TJ, Spits H, Cantrell DA. Phosphoinositide-dependent kinase 1 controls migration and malignant transformation but not cell growth and proliferation in PTEN-null lymphocytes. ACTA ACUST UNITED AC 2009; 206:2441-54. [PMID: 19808258 PMCID: PMC2768858 DOI: 10.1084/jem.20090219] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In normal T cell progenitors, phosphoinositide-dependent kinase l (PDK1)–mediated phosphorylation and activation of protein kinase B (PKB) is essential for the phosphorylation and inactivation of Foxo family transcription factors, and also controls T cell growth and proliferation. The current study has characterized the role of PDK1 in the pathology caused by deletion of the tumor suppressor phosphatase and tensin homologue deleted on chromosome 10 (PTEN). PDK1 is shown to be essential for lymphomagenesis caused by deletion of PTEN in T cell progenitors. However, PTEN deletion bypasses the normal PDK1-controlled signaling pathways that determine thymocyte growth and proliferation. PDK1 does have important functions in PTEN-null thymocytes, notably to control the PKB–Foxo signaling axis and to direct the repertoire of adhesion and chemokine receptors expressed by PTEN-null T cells. The results thus provide two novel insights concerning pathological signaling caused by PTEN loss in lymphocytes. First, PTEN deletion bypasses the normal PDK1-controlled metabolic checkpoints that determine cell growth and proliferation. Second, PDK1 determines the cohort of chemokine and adhesion receptors expressed by PTEN-null cells, thereby controlling their migratory capacity.
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Affiliation(s)
- David K Finlay
- Division of Immunology and Cell Biology, University of Dundee, Dundee DD15EH, Scotland, UK
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733
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Maiese K, Hou J, Chong ZZ, Shang YC. Erythropoietin, forkhead proteins, and oxidative injury: biomarkers and biology. ScientificWorldJournal 2009; 9:1072-104. [PMID: 19802503 PMCID: PMC2762199 DOI: 10.1100/tsw.2009.121] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Oxidative stress significantly impacts multiple cellular pathways that can lead to the initiation and progression of varied disorders throughout the body. It therefore becomes imperative to elucidate the components and function of novel therapeutic strategies against oxidative stress to further clinical diagnosis and care. In particular, both the growth factor and cytokine erythropoietin (EPO), and members of the mammalian forkhead transcription factors of the O class (FoxOs), may offer the greatest promise for new treatment regimens, since these agents and the cellular pathways they oversee cover a range of critical functions that directly influence progenitor cell development, cell survival and degeneration, metabolism, immune function, and cancer cell invasion. Furthermore, both EPO and FoxOs function not only as therapeutic targets, but also as biomarkers of disease onset and progression, since their cellular pathways are closely linked and overlap with several unique signal transduction pathways. Yet, EPO and FoxOs may sometimes have unexpected and undesirable effects that can raise caution for these agents and warrant further investigations. Here we present the exciting as well as the complex role that EPO and FoxOs possess to uncover the benefits as well as the risks of these agents for cell biology and clinical care in processes that range from stem cell development to uncontrolled cellular proliferation.
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Affiliation(s)
- Kenneth Maiese
- Division of Cellular and Molecular Cerebral Ischemia, Wayne State University School of Medicine, Detroit, Michigan, USA.
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734
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Zhou W, Cao Q, Peng Y, Zhang QJ, Castrillon DH, DePinho RA, Liu ZP. FoxO4 inhibits NF-kappaB and protects mice against colonic injury and inflammation. Gastroenterology 2009; 137:1403-14. [PMID: 19560465 PMCID: PMC2764529 DOI: 10.1053/j.gastro.2009.06.049] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Revised: 05/22/2009] [Accepted: 06/11/2009] [Indexed: 01/09/2023]
Abstract
BACKGROUND & AIMS FoxO4 is a member of the forkhead box transcription factor O (FoxO) subfamily. FoxO proteins are involved in diverse biological processes. In this study, we examine the role of FoxO4 in intestinal mucosal immunity and inflammatory bowel disease (IBD). METHODS Foxo4-null mice were subjected to trinitrobenzene sulfonic acid (TNBS) treatment. Microarray analysis and quantitative reverse transcription polymerase chain reaction were used to identify the cytokine transcripts that were altered by Foxo4 deletion. The effects of Foxo4 deficiency on the intestinal epithelial permeability and levels of tight junction proteins were examined by permeable fluorescent dye and Western blot. The molecular and cellular mechanisms by which FoxO4 regulates the mucosal immunity were explored through immunologic and biochemical analyses. The expression level of FoxO4 in intestinal epithelial cells of patients with IBD was examined with immunohistochemistry. RESULTS Foxo4-null mice were more susceptible to TNBS injury-induced colitis. The chemokine CCL5 is significantly up-regulated in the colonic epithelial cells of Foxo4-null mice, with increased recruitment of CD4(+) intraepithelial T cells and up-regulation of cytokines interferon-gamma and tumor necrosis factor-alpha in the colon. Foxo4 deficiency also resulted in an increase in intestinal epithelial permeability and down-regulation of the tight junction proteins ZO-1 and claudin-1. Mechanistically, FoxO4 inhibited the transcriptional activity of nuclear factor-kappaB (NF-kappaB), and Foxo4 deficiency is associated with increased NF-kappaB activity in vivo. FoxO4 transcription is transiently repressed in response to TNBS treatment and in patients with IBD. CONCLUSION These results indicate that FoxO4 is an endogenous inhibitor of NF-kappaB and identify a novel function of FoxO4 in the regulation of NF-kappaB-mediated mucosal immunity.
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Affiliation(s)
- Wen Zhou
- Department of Internal Medicine and Molecular Biology, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas, TX 75390-9148, USA
| | - Qian Cao
- Department of Gastroenterology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, China
| | - Yan Peng
- Department of Internal Pathology, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas, TX 75390-9148, USA
| | - Qing-Jun Zhang
- Department of Internal Medicine and Molecular Biology, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas, TX 75390-9148, USA
| | - Diego H. Castrillon
- Department of Internal Pathology, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas, TX 75390-9148, USA
| | - Ronald A. DePinho
- Department of Medical Oncology and Center for Applied Cancer Science, Belfer Foundation Institute for Innovative Cancer Science, Dana-Farber Cancer Institute, and Departments of Medicine and Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Zhi-Ping Liu
- Department of Internal Medicine and Molecular Biology, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas, TX 75390-9148, USA,To whom correspondence should be addressed:, Ph: 214 648-1485, Fx: 214 648-1450, E-mail:
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735
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Tanaka J, Qiang L, Banks AS, Welch CL, Matsumoto M, Kitamura T, Ido-Kitamura Y, DePinho RA, Accili D. Foxo1 links hyperglycemia to LDL oxidation and endothelial nitric oxide synthase dysfunction in vascular endothelial cells. Diabetes 2009; 58:2344-54. [PMID: 19584310 PMCID: PMC2750207 DOI: 10.2337/db09-0167] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Atherosclerotic cardiovascular disease is the leading cause of death among people with diabetes. Generation of oxidized LDLs and reduced nitric oxide (NO) availability because of endothelial NO synthase (eNOS) dysfunction are critical events in atherosclerotic plaque formation. Biochemical mechanism leading from hyperglycemia to oxLDL formation and eNOS dysfunction is unknown. RESEARCH DESIGN AND METHODS We show that glucose, acting through oxidative stress, activates the transcription factor Foxo1 in vascular endothelial cells. RESULTS Foxo1 promotes inducible NOS (iNOS)-dependent NO-peroxynitrite generation, which leads in turn to LDL oxidation and eNOS dysfunction. We demonstrate that Foxo1 gain-of-function mimics the effects of hyperglycemia on this process, whereas conditional Foxo1 knockout in vascular endothelial cells prevents it. CONCLUSIONS The findings reveal a hitherto unsuspected role of the endothelial iNOS-NO-peroxynitrite pathway in lipid peroxidation and eNOS dysfunction and suggest that Foxo1 activation in response to hyperglycemia brings about proatherogenic changes in vascular endothelial cell function.
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Affiliation(s)
- Jun Tanaka
- Department of Medicine, College of Physicians and Surgeons of Columbia University, New York, New York
| | - Li Qiang
- Department of Medicine, College of Physicians and Surgeons of Columbia University, New York, New York
| | - Alexander S. Banks
- Department of Medicine, College of Physicians and Surgeons of Columbia University, New York, New York
| | - Carrie L. Welch
- Department of Medicine, College of Physicians and Surgeons of Columbia University, New York, New York
| | - Michihiro Matsumoto
- Department of Medicine, College of Physicians and Surgeons of Columbia University, New York, New York
| | - Tadahiro Kitamura
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan
| | - Yukari Ido-Kitamura
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan
| | - Ronald A. DePinho
- Center for Applied Cancer Science, Departments of Medical Oncology, Medicine and Genetics, and Belfer Institute for Innovative Cancer Science, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts
| | - Domenico Accili
- Department of Medicine, College of Physicians and Surgeons of Columbia University, New York, New York
- Corresponding author: Domenico Accili,
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736
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Abstract
A screen for increased longevity in Caenorhabditis elegans has identified a transcription factor that programs cells for resistance to oxidative stress, DNA repair and cell cycle control. The mammalian orthologs of this factor are referred to as 'Foxo' for 'Forkhead box', with the second 'o' in the name denoting a subfamily of four members related by sequence. This family of factors is regulated by growth factors, oxidative stress or nutrient deprivation. Thus, it might readily control the inflammatory conflagration associated with infection-driven lymphocyte proliferation. Surprisingly, the first insights into Foxo-mediated immune regulation have instead revealed direct control of highly specialized genes of the adaptive immune system.
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Affiliation(s)
- Stephen M Hedrick
- Section of Molecular Biology and Department of Cellular and Molecular Medicine, The University of California, San Diego, La Jolla, California, USA.
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737
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Plum L, Lin HV, Dutia R, Tanaka J, Aizawa KS, Matsumoto M, Kim AJ, Cawley NX, Paik JH, Loh YP, DePinho RA, Wardlaw SL, Accili D. The obesity susceptibility gene Cpe links FoxO1 signaling in hypothalamic pro-opiomelanocortin neurons with regulation of food intake. Nat Med 2009; 15:1195-201. [PMID: 19767734 PMCID: PMC2777744 DOI: 10.1038/nm.2026] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Accepted: 08/11/2009] [Indexed: 12/03/2022]
Abstract
Reduced food intake brings about an adaptive decrease in energy expenditure that contributes to the recidivism of obesity following weight loss. Insulin and leptin inhibit food intake through actions in the central nervous system that are partly mediated by FoxO1. We show that FoxO1 ablation in pro–opiomelanocortin (Pomc) neurons (Pomc–Foxo1−/−) reduces food intake without affecting energy expenditure. Analyses of hypothalamic neuropeptides in Pomc–Foxo1−/− mice reveal selective increases of α–Msh and COOH–cleaved β–endorphin, the products of Carboxypeptidase E (Cpe)–dependent processing of Pomc. We show that Cpe is decreased in diet–induced obesity, and that FoxO1 deletion offsets the decrease, protecting against weight gain. Moreover, moderate Cpe overexpression in the arcuate nucleus phenocopies features of the FoxO1 mutation. The dissociation of food intake from energy expenditure in Pomc–Foxo1−/− mice represents a model for therapeutic intervention in obesity, and raises the possibility of targeting Cpe to develop weight loss medications.
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Affiliation(s)
- Leona Plum
- Naomi Berrie Diabetes Center and Department of Medicine, Columbia University, New York, New York, USA
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738
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Georges AB, Benayoun BA, Caburet S, Veitia RA. Generic binding sites, generic DNA‐binding domains: where does specific promoter recognition come from? FASEB J 2009; 24:346-56. [DOI: 10.1096/fj.09-142117] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Adrien B. Georges
- Unité Mixte de Recherche 7592‐Centre National de la Recherche ScientifiqueInstitut Jacques MonodParisFrance
| | - Berenice A. Benayoun
- Unité Mixte de Recherche 7592‐Centre National de la Recherche ScientifiqueInstitut Jacques MonodParisFrance
| | - Sandrine Caburet
- Unité Mixte de Recherche 7592‐Centre National de la Recherche ScientifiqueInstitut Jacques MonodParisFrance
| | - Reiner A. Veitia
- Unité Mixte de Recherche 7592‐Centre National de la Recherche ScientifiqueInstitut Jacques MonodParisFrance
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739
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Matsukawa M, Sakamoto H, Kawasuji M, Furuyama T, Ogawa M. Different roles of Foxo1 and Foxo3 in the control of endothelial cell morphology. Genes Cells 2009; 14:1167-81. [PMID: 19747349 DOI: 10.1111/j.1365-2443.2009.01343.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Foxo1, a member of the Foxo subfamily of forkhead box transcription factors, is known to be essential for progression of normal vascular development in the mouse embryos. In the cultures of endothelial cells derived from embryonic stem cells, Foxo1-deficient endothelial cells exhibit an abnormal morphological response to vascular endothelial growth factor-A (VEGF-A), which is characterized by a lack of cell elongation, yet the molecular mechanisms governing endothelial cell morphology under angiogenic stimulation remain unknown. Here, we report that transforming growth actor-beta also induces endothelial cell elongation in collaboration with Foxo1 and VEGF-A. Furthermore, tetracycline-regulated induction of Foxo3, another member of the Foxo subfamily, into Foxo1-null endothelial cells failed to restore abnormal morphological response to VEGF-A at an early differentiation stage. In contrast, Foxo1 and Foxo3 exerted the same function at a late differentiation stage, i.e. enhancement of VEGF responsiveness and promotion of cell elongation. Our results provide evidence that endothelial cell morphology is regulated by several mechanisms in which Foxo1 and Foxo3 express distinct functional properties depending on differentiation stages.
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Affiliation(s)
- Mai Matsukawa
- Department of Cell Differentiation, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan
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740
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Qiong Z, Ruofan H, Xiaohua L, Xinli Z, Jingwei J, Zhaohui C. Role of dephosphorylation of FOXO1 on apoptosis induced by wortmannin for non-Hodgkin’s lymphoma cells. Mol Biol Rep 2009; 37:2397-402. [DOI: 10.1007/s11033-009-9748-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Accepted: 08/05/2009] [Indexed: 11/22/2022]
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741
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Shukla S, Shukla M, Maclennan GT, Fu P, Gupta S. Deregulation of FOXO3A during prostate cancer progression. Int J Oncol 2009; 34:1613-20. [PMID: 19424579 DOI: 10.3892/ijo_00000291] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Forkhead box transcription factor FOXO3A, an important regulator of cellular function, is thought to act as a tumor suppressor. We studied whether alterations in FOXO3A activity occur in prostate tumorigenesis. Our studies demonstrate that FOXO3A activity is negatively regulated by Akt/PKB through posttranslational modifications. In prostate cancer cells, Akt activation causes increased accumulation of FOXO3A and its binding chaperone protein 14-3-3 in the cytosol. Higher levels of FOXO3A in the cytosol correlated with phosphorylation at Ser253, which accounted for its nuclear exclusion. Dominant negative Akt approach in PC-3 cells increased FOXO3A accumulation in the nucleus, causing upregulation of the downstream target, MnSOD. Conversely, stable DU145-Akt over-expressing cells exhibited decreased FOXO3A levels in the nucleus. Similar findings were noted in prostate tumor specimens, in which marked cytoplasmic accumulation of FOXO3A and 14-3-3 in prostate tumors was observed with increasing Gleason grade, in contrast to exclusively nuclear accumulation in benign prostate cells. These findings correlate with decreased FOXO3A DNA binding activity along with down-modulation of FOXO3A transcriptional activity with increasing tumor grade. Our findings demonstrate that tumor associated alterations and redistribution of FOXO3A are frequent events in the etiology of prostate cancer.
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Affiliation(s)
- Sanjeev Shukla
- Department of Urology, Case Western Reserve University and University Hospitals Case Medical Center, Cleveland, OH 44106, USA
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742
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Lei H, Quelle FW. FOXO transcription factors enforce cell cycle checkpoints and promote survival of hematopoietic cells after DNA damage. Mol Cancer Res 2009; 7:1294-303. [PMID: 19671690 DOI: 10.1158/1541-7786.mcr-08-0531] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The PI3K/AKT signaling pathway contributes to cell cycle progression of cytokine-dependent hematopoietic cells under normal conditions, and it is absolutely required to override DNA damage-induced cell cycle arrest checkpoints in these cells. Phosphatidylinositol-3-kinase (PI3K)/AKT activity also correlates with Cdk2 activity in hematopoietic cells, suggesting that Cdk2 activation may be a relevant end point for this signaling pathway. However, mediators downstream of AKT in this pathway have not been defined. The forkhead transcription factor O (FOXO) family are negatively regulated by AKT-dependent phosphorylation and are known regulators of genes affecting cell cycle progression. We show that enhanced FOXO activity replicates the effect of PI3K inhibitors in enforcing G(1) and G(2) phase arrest after DNA damage. Conversely, knockdown of endogenous FOXO proteins increased Cdk2 activity and overrode DNA damage checkpoints in cells lacking PI3K activity. Moreover, loss of FOXO activity caused an increase in sensitivity to cisplatin-induced cell death, which was associated with failure to arrest cell cycle progression in the face of DNA damage caused by this chemotherapeutic agent. These cell cycle arrests were dependent on p27 expression when mediated by FOXO3a alone, but also involve p27-independent mechanisms when promoted by endogenous FOXO proteins. Together, these observations show that FOXO proteins enforce DNA damage-induced cell cycle arrest in hematopoietic cells. Inhibition of FOXO activity by cytokine-induced PI3K/AKT signaling is sufficient to override these DNA damage-induced cell cycle checkpoints, but may negatively impact hematopoietic cell viability.
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Affiliation(s)
- Hong Lei
- Department of Pharmacology, The University of Iowa, Carver College of Medicine, Iowa City, IA 52242, USA
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743
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Pouyet L, Carrier A. Mutant mouse models of oxidative stress. Transgenic Res 2009; 19:155-64. [PMID: 19662508 DOI: 10.1007/s11248-009-9308-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Accepted: 07/21/2009] [Indexed: 01/14/2023]
Abstract
Oxidative stress corresponds to an excess in reactive oxygen species (ROS) including free radicals which are highly reactive with cellular constituents. Thereby ROS induce damage to DNA, proteins and lipids, which are all involved in the etiology of numerous pathologies such as cancer. To prevent potential damage, a tight regulation of ROS level is achieved through numerous enzyme systems and small molecules such as glutathione and vitamin C. Mutant mouse models targeting antioxidant enzymes have confirmed their essential role in ROS level control, and have shown a limited redundancy of their activity. Additionally, a number of other mutant mouse models exhibit increased ROS levels, suggesting an antioxidant role for the corresponding targeted gene. This is the case for mice deficient for the transcription factors p53, JunD, FoxOs, and HIF-2alpha, which are involved in the modulation of antioxidant enzymes expression. Mice deficient either for the stress factor TP53INP1, which is a target of p53, or for ATM involved in DNA damage sensoring, also show a constitutive oxidative stress. Finally, the last reported case of mice with a permanent oxidative stress targets Bmi which is a transcriptional repressor of the polycomb family. Interestingly, most of these "oxidative stressed mice" either spontaneously develop cancers or are more susceptible than wild-type to tumor-induced protocols. Altogether, these models markedly reinforce the causal link between oxidative stress and cancer. In the future, they will be helpful tools for basic research aimed at unraveling the interplay between redox control actors as well as their relative importance. In addition, these oxidative stressed mouse models may be useful for applied research in particular in preclinical assays where redox status regulation is absolutely required.
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Affiliation(s)
- Laurent Pouyet
- INSERM U624, Case 915 Parc Scientifique de Luminy, 13288 Marseille Cedex 9, France
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744
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Jagani Z, Song K, Kutok JL, Dewar MR, Melet A, Santos T, Grassian A, Ghaffari S, Wu C, Yeckes-Rodin H, Rodin HY, Ren R, Miller K, Khosravi-Far R. Proteasome inhibition causes regression of leukemia and abrogates BCR-ABL-induced evasion of apoptosis in part through regulation of forkhead tumor suppressors. Cancer Res 2009; 69:6546-55. [PMID: 19654305 DOI: 10.1158/0008-5472.can-09-0605] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BCR-ABL plays an essential role in the pathogenesis of chronic myeloid leukemia (CML) and some cases of acute lymphocytic leukemia (ALL). Although ABL kinase inhibitors have shown great promise in the treatment of CML, the persistence of residual disease and the occurrence of resistance have prompted investigations into the molecular effectors of BCR-ABL. Here, we show that BCR-ABL stimulates the proteasome-dependent degradation of members of the forkhead family of tumor suppressors in vitro, in an in vivo animal model, and in samples from patients with BCR-ABL-positive CML or ALL. As several downstream mediators of BCR-ABL are regulated by the proteasome degradation pathway, we also show that inhibition of this pathway, using bortezomib, causes regression of CML-like disease. Bortezomib treatment led to inhibition of BCR-ABL-induced suppression of FoxO proteins and their proapoptotic targets, tumor necrosis factor-related apoptosis-inducing ligand and BIM, thereby providing novel insights into the molecular effects of proteasome inhibitor therapy. We additionally show sensitivity of imatinib-resistant BCR-ABL T315I cells to bortezomib. Our data delineate the involvement of FoxO proteins in BCR-ABL-induced evasion of apoptosis and provide evidence that bortezomib is a candidate therapeutic in the treatment of BCR-ABL-induced leukemia.
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Affiliation(s)
- Zainab Jagani
- Department of Pathology, Harvard Medical School and Beth Israel Deaconess Medical Center, Boston, Massachusetts 02215, USA
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745
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Redox-sensitive cysteines bridge p300/CBP-mediated acetylation and FoxO4 activity. Nat Chem Biol 2009; 5:664-72. [PMID: 19648934 DOI: 10.1038/nchembio.194] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Accepted: 05/12/2009] [Indexed: 12/14/2022]
Abstract
Cellular damage invoked by reactive oxygen species plays a key role in the pathobiology of cancer and aging. Forkhead box class O (FoxO) transcription factors are involved in various cellular processes including cell cycle regulation, apoptosis and resistance to reactive oxygen species, and studies in animal models have shown that these transcription factors are of vital importance in tumor suppression, stem cell maintenance and lifespan extension. Here we report that the activity of FoxO in human cells is directly regulated by the cellular redox state through a unique mechanism in signal transduction. We show that reactive oxygen species induce the formation of cysteine-thiol disulfide-dependent complexes of FoxO and the p300/CBP acetyltransferase, and that modulation of FoxO biological activity by p300/CBP-mediated acetylation is fully dependent on the formation of this redox-dependent complex. These findings directly link cellular redox status to the activity of the longevity protein FoxO.
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746
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Yang JY, Hung MC. A new fork for clinical application: targeting forkhead transcription factors in cancer. Clin Cancer Res 2009; 15:752-7. [PMID: 19188143 DOI: 10.1158/1078-0432.ccr-08-0124] [Citation(s) in RCA: 199] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Forkhead O transcription factors (FOXO) play a pivotal role in the regulation of a myriad of cellular functions including cell cycle arrest, cell death, and protection from stress stimuli. Activation of cell survival pathways such as phosphoinositide-3-kinase/AKT/IKK or RAS/mitogen-activated protein kinase are known to phosphorylate FOXOs at different sites which cause FOXOs nuclear exclusion and degradation, resulting in the suppression of FOXO's transcriptional activity. Perturbation of FOXO's function leads to deregulated cell proliferation and accumulation of DNA damage, resulting in diseases such as cancer. Emerging evidence shows that active FOXO proteins are crucial for keeping cells in check; and inactivation of FOXO proteins is associated with tumorigenesis, including breast cancer, prostate cancer, glioblastoma, rhabdomyosarcoma, and leukemia. Moreover, clinically used drugs like paclitaxel, imatinib, and doxorubicin have been shown to achieve their therapeutic effects through activation of FOXO3a and FOXO3a targets. In this review, we will focus the novel functions of FOXOs revealed in recent studies and further highlight FOXOs as new therapeutic targets in a broad spectrum of cancers.
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Affiliation(s)
- Jer-Yen Yang
- Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA
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747
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Maiese K, Chong ZZ, Shang YC, Hou J. A "FOXO" in sight: targeting Foxo proteins from conception to cancer. Med Res Rev 2009; 29:395-418. [PMID: 18985696 DOI: 10.1002/med.20139] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The successful treatment for multiple disease entities can rest heavily upon the ability to elucidate the intricate relationships that govern cellular proliferation, metabolism, survival, and inflammation. Here we discuss the therapeutic potential of the mammalian forkhead transcription factors predominantly in the O class, FoxO1, FoxO3, FoxO4, and FoxO6, which play a significant role during normal cellular function as well as during progressive disease. These transcription factors are integrated with several signal transduction pathways, such as Wnt proteins, that can regulate a broad array of cellular process that include stem cell proliferation, aging, and malignancy. FoxO transcription factors are attractive considerations for strategies directed against human cancer in light of their pro-apoptotic effects and ability to lead to cell cycle arrest. Yet, FoxO proteins can be associated with infertility, cellular degeneration, and unchecked cellular proliferation. As our knowledge continues to develop for this novel family of proteins, potential clinical applications for the FoxO family should heighten our ability to limit disease progression without clinical compromise.
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Affiliation(s)
- Kenneth Maiese
- Division of Cellular and Molecular Cerebral Ischemia, Department of Neurology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.
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748
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Guttilla IK, White BA. Coordinate regulation of FOXO1 by miR-27a, miR-96, and miR-182 in breast cancer cells. J Biol Chem 2009; 284:23204-16. [PMID: 19574223 DOI: 10.1074/jbc.m109.031427] [Citation(s) in RCA: 471] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The FOXO1 transcription factor orchestrates the regulation of genes involved in the apoptotic response, cell cycle checkpoints, and cellular metabolism. FOXO1 is a putative tumor suppressor, and the expression of this gene is dysregulated in some cancers, including prostate and endometrial cancers. However, the molecular mechanism resulting in aberrant expression of human FOXO1 in cancer cells is poorly understood. We show here that FOXO1 mRNA is down-regulated in breast tumor samples as compared with normal breast tissue. Silencing of the microRNA processing enzymes, Drosha and Dicer, led to an increase in FOXO1 expression. We also identified functional and specific microRNA target sites in the FOXO1 3'-untranslated region for miR-27a, miR-96, and miR-182, microRNAs that have previously been linked to oncogenic transformation. The three microRNAs, miR-27a, miR-96 and miR-182, were observed to be highly expressed in MCF-7 breast cancer cells, in which the level of FOXO1 protein is very low. Antisense inhibitors to each of these microRNAs led to a significant increase in endogenous FOXO1 expression and to a decrease in cell number in a manner that was blocked by FOXO1 siRNA. Overexpression of FOXO1 resulted in decreased cell viability because of inhibition of cell cycle traverse and induction of cell death. We have identified a novel mechanism of FOXO1 regulation, and targeting of FOXO1 by microRNAs may contribute to transformation or maintenance of an oncogenic state in breast cancer cells.
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Affiliation(s)
- Irene K Guttilla
- Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
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749
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FOXO3a promotes tumor cell invasion through the induction of matrix metalloproteinases. Mol Cell Biol 2009; 29:4906-17. [PMID: 19564415 DOI: 10.1128/mcb.00077-09] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The role of the Forkhead transcription factor FOXO3a in processes that promote tumor metastasis is poorly defined. Here, we show that depletion of FOXO3a from cancer cells leads to decreased tumor size specifically due to attenuated invasive migration. During tumor progression, an increase in tumor mass is concomitant with serum deprivation prior to tumor angiogenesis. We show that nuclear retention of FOXO3a due to serum starvation results in greatly increased cancer cell invasion. Exploration of the mechanism by which FOXO3a promotes invasive migration revealed that it induces the expression of matrix metalloproteinase 9 (MMP-9) and MMP-13, both of which have been causally linked to the invasion and progression of numerous human solid tumors. Our results link Forkhead transcription factors to a previously unexplored function in cancer progression by promoting extracellular matrix degradation, allowing tumors to invade neighboring tissues and ultimately metastasize to distant organs.
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750
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Abstract
An understanding of the mechanisms that govern pancreatic endocrine cell ontogeny may offer strategies for their somatic replacement in diabetic patients. During embryogenesis, transcription factor FoxO1 is expressed in pancreatic progenitor cells. Subsequently, it becomes restricted to beta cells and to a rare population of insulin-negative juxtaductal cells (FoxO1+ Ins(-)). It is unclear whether FoxO1+ Ins(-) cells give rise to endocrine cells. To address this question, we first evaluated FoxO1's role in pancreas development using gain- and loss-of-function alleles in mice. Premature FoxO1 activation in pancreatic progenitors promoted alpha-cell formation but curtailed exocrine development. Conversely, FoxO1 ablation in pancreatic progenitor cells, but not in committed endocrine progenitors or terminally differentiated beta cells, selectively increased juxtaductal beta cells. As these data indicate an involvement of FoxO1 in pancreatic lineage determination, FoxO1+ Ins(-) cells were clonally isolated and assayed for their capacity to undergo endocrine differentiation. Upon FoxO1 activation, FoxO1+ Ins(-) cultures converted into glucagon-producing cells. We conclude that FoxO1+ Ins(-) juxtaductal cells represent a hitherto-unrecognized pancreatic cell population with in vitro capability of endocrine differentiation.
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