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Sizer RE, Butterfield SP, Hancocks LA, Gato De Sousa L, White RJ. Selective Occupation by E2F and RB of Loci Expressed by RNA Polymerase III. Cancers (Basel) 2024; 16:481. [PMID: 38339234 PMCID: PMC10854548 DOI: 10.3390/cancers16030481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/15/2024] [Accepted: 01/15/2024] [Indexed: 02/12/2024] Open
Abstract
In all cases tested, TFIIIB is responsible for recruiting pol III to its genetic templates. In mammalian cells, RB binds TFIIIB and prevents its interactions with both promoter DNA and pol III, thereby suppressing transcription. As TFIIIB is not recruited to its target genes when bound by RB, the mechanism predicts that pol III-dependent templates will not be occupied by RB; this contrasts with the situation at most genes controlled by RB, where it can be tethered by promoter-bound sequence-specific DNA-binding factors such as E2F. Contrary to this prediction, however, ChIP-seq data reveal the presence of RB in multiple cell types and the related protein p130 at many loci that rely on pol III for their expression, including RMRP, RN7SL, and a variety of tRNA genes. The sets of genes targeted varies according to cell type and growth state. In such cases, recruitment of RB and p130 can be explained by binding of E2F1, E2F4 and/or E2F5. Genes transcribed by pol III had not previously been identified as common targets of E2F family members. The data provide evidence that E2F may allow for the selective regulation of specific non-coding RNAs by RB, in addition to its influence on overall pol III output through its interaction with TFIIIB.
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Affiliation(s)
| | | | | | | | - Robert J. White
- Department of Biology, University of York, York YO10 5DD, UK; (R.E.S.)
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2
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Abbas H, Derkaoui DK, Jeammet L, Adicéam E, Tiollier J, Sicard H, Braun T, Poyet JL. Apoptosis Inhibitor 5: A Multifaceted Regulator of Cell Fate. Biomolecules 2024; 14:136. [PMID: 38275765 PMCID: PMC10813780 DOI: 10.3390/biom14010136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/17/2024] [Accepted: 01/19/2024] [Indexed: 01/27/2024] Open
Abstract
Apoptosis, or programmed cell death, is a fundamental process that maintains tissue homeostasis, eliminates damaged or infected cells, and plays a crucial role in various biological phenomena. The deregulation of apoptosis is involved in many human diseases, including cancer. One of the emerging players in the intricate regulatory network of apoptosis is apoptosis inhibitor 5 (API5), also called AAC-11 (anti-apoptosis clone 11) or FIF (fibroblast growth factor-2 interacting factor). While it may not have yet the same level of notoriety as some other cancer-associated proteins, API5 has garnered increasing attention in the cancer field in recent years, as elevated API5 levels are often associated with aggressive tumor behavior, resistance to therapy, and poor patient prognosis. This review aims to shed light on the multifaceted functions and regulatory mechanisms of API5 in cell fate decisions as well as its interest as therapeutic target in cancer.
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Affiliation(s)
- Hafsia Abbas
- Université Oran 1, Ahmed Ben Bella, Oran 31000, Algeria; (H.A.); (D.K.D.)
| | | | - Louise Jeammet
- Jalon Therapeutics, 75010 Paris, France; (L.J.); (J.T.); (H.S.)
| | - Emilie Adicéam
- Jalon Therapeutics, 75010 Paris, France; (L.J.); (J.T.); (H.S.)
| | - Jérôme Tiollier
- Jalon Therapeutics, 75010 Paris, France; (L.J.); (J.T.); (H.S.)
| | - Hélène Sicard
- Jalon Therapeutics, 75010 Paris, France; (L.J.); (J.T.); (H.S.)
| | - Thorsten Braun
- Laboratoire de Transfert des Leucémies, EA3518, Institut de Recherche Saint Louis, Hôpital Saint Louis, Université de Paris, 75010 Paris, France;
- AP-HP, Service d’Hématologie Clinique, Hôpital Avicenne, Université Paris XIII, 93000 Bobigny, France
- OPALE Carnot Institute, The Organization for Partnerships in Leukemia, Hôpital Saint-Louis, 75010 Paris, France
| | - Jean-Luc Poyet
- INSERM UMRS976, Institut de Recherche Saint Louis, Hôpital Saint Louis, 75010 Paris, France
- Université Paris Cité, 75015 Paris, France
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CCAAT/Enhancer-Binding Protein ε 27 Antagonism of GATA-1 Transcriptional Activity in the Eosinophil Is Mediated by a Unique N-Terminal Repression Domain, Is Independent of Sumoylation and Does Not Require DNA Binding. Int J Mol Sci 2021; 22:ijms222312689. [PMID: 34884493 PMCID: PMC8657826 DOI: 10.3390/ijms222312689] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 11/18/2021] [Accepted: 11/19/2021] [Indexed: 11/16/2022] Open
Abstract
CCAAT/enhancer binding protein epsilon (C/EBPε) is required for eosinophil differentiation, lineage-specific gene transcription, and expression of C/EBPε32 and shorter 27kD and 14kD isoforms is developmentally regulated during this process. We previously defined the 27kD isoform (C/EBPε27) as an antagonist of GATA-1 transactivation of the eosinophil's major basic protein-1 (MBP1) P2-promoter, showing C/EBPε27 and GATA-1 physically interact. In the current study, we used a Tat-C/EBPε27 fusion protein for cell/nuclear transduction of an eosinophil myelocyte cell line to demonstrate that C/EBPε27 is a potent repressor of MBP1 transcription. We performed structure-function analyses of C/EBPε27 mapping its repressor domains, comparing it to C/EBPε32 and C/EBPε14, using GATA-1 co-transactivation of the MBP1-P2 promoter. Results show C/EBPε27 repression of GATA-1 is mediated by its unique 68aa N-terminus combined with previously identified RDI domain. This repressor activity does not require, but is enhanced by, DNA binding via the basic region of C/EBPε27 but independent of sumoylation of the RDI core "VKEEP" sumoylation site. These findings identify the N-terminus of C/EBPε27 as the minimum repressor domain required for antagonism of GATA-1 in the eosinophil. C/EBPε27 repression of GATA-1 occurs via a combination of both C/EBPε27-GATA-1 protein-protein interaction and C/EBPε27 binding to a C/EBP site in the MBP1 promoter. The C/EBPε27 isoform may serve to titrate and/or turn off eosinophil granule protein genes like MBP1 during eosinophil differentiation, as these genes are ultimately silenced in the mature cell. Understanding the functionality of C/EBPε27 in eosinophil development may prove promising in developing therapeutics that reduce eosinophil proliferation in allergic diseases.
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Hanaki S, Habara M, Masaki T, Maeda K, Sato Y, Nakanishi M, Shimada M. PP1 regulatory subunit NIPP1 regulates transcription of E2F1 target genes following DNA damage. Cancer Sci 2021; 112:2739-2752. [PMID: 33939241 PMCID: PMC8253265 DOI: 10.1111/cas.14924] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 04/14/2021] [Accepted: 04/14/2021] [Indexed: 12/21/2022] Open
Abstract
DNA damage induces transcriptional repression of E2F1 target genes and a reduction in histone H3‐Thr11 phosphorylation (H3‐pThr11) at E2F1 target gene promoters. Dephosphorylation of H3‐pThr11 is partly mediated by Chk1 kinase and protein phosphatase 1γ (PP1γ) phosphatase. Here, we isolated NIPP1 as a regulator of PP1γ‐mediated H3‐pThr11 by surveying nearly 200 PP1 interactor proteins. We found that NIPP1 inhibits PP1γ‐mediated dephosphorylation of H3‐pThr11 both in vivo and in vitro. By generating NIPP1‐depleted cells, we showed that NIPP1 is required for cell proliferation and the expression of E2F1 target genes. Upon DNA damage, activated protein kinase A (PKA) phosphorylated the NIPP1‐Ser199 residue, adjacent to the PP1 binding motif (RVxF), and triggered the dissociation of NIPP1 from PP1γ, leading to the activation of PP1γ. Furthermore, the inhibition of PKA activity led to the activation of E2F target genes. Statistical analysis confirmed that the expression of NIPP1 was positively correlated with E2F target genes. Taken together, these findings demonstrate that the PP1 regulatory subunit NIPP1 modulates E2F1 target genes by linking PKA and PP1γ during DNA damage.
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Affiliation(s)
- Shunsuke Hanaki
- Department of Biochemistry, Joint Faculty of Veterinary Science, Yamaguchi University, Yamaguchi, Japan
| | - Makoto Habara
- Department of Biochemistry, Joint Faculty of Veterinary Science, Yamaguchi University, Yamaguchi, Japan
| | - Takahiro Masaki
- Department of Biochemistry, Joint Faculty of Veterinary Science, Yamaguchi University, Yamaguchi, Japan
| | - Keisuke Maeda
- Department of Biochemistry, Joint Faculty of Veterinary Science, Yamaguchi University, Yamaguchi, Japan
| | - Yuki Sato
- Department of Biochemistry, Joint Faculty of Veterinary Science, Yamaguchi University, Yamaguchi, Japan
| | - Makoto Nakanishi
- Division of Cancer Biology, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Midori Shimada
- Department of Biochemistry, Joint Faculty of Veterinary Science, Yamaguchi University, Yamaguchi, Japan
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Arizmendi-Izazaga A, Navarro-Tito N, Jiménez-Wences H, Mendoza-Catalán MA, Martínez-Carrillo DN, Zacapala-Gómez AE, Olea-Flores M, Dircio-Maldonado R, Torres-Rojas FI, Soto-Flores DG, Illades-Aguiar B, Ortiz-Ortiz J. Metabolic Reprogramming in Cancer: Role of HPV 16 Variants. Pathogens 2021; 10:pathogens10030347. [PMID: 33809480 PMCID: PMC7999907 DOI: 10.3390/pathogens10030347] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/13/2021] [Accepted: 03/14/2021] [Indexed: 12/12/2022] Open
Abstract
Metabolic reprogramming is considered one of the hallmarks in cancer and is characterized by increased glycolysis and lactate production, even in the presence of oxygen, which leads the cancer cells to a process called “aerobic glycolysis” or “Warburg effect”. The E6 and E7 oncoproteins of human papillomavirus 16 (HPV 16) favor the Warburg effect through their interaction with a molecule that regulates cellular metabolism, such as p53, retinoblastoma protein (pRb), c-Myc, and hypoxia inducible factor 1α (HIF-1α). Besides, the impact of the E6 and E7 variants of HPV 16 on metabolic reprogramming through proteins such as HIF-1α may be related to their oncogenicity by favoring cellular metabolism modifications to satisfy the energy demands necessary for viral persistence and cancer development. This review will discuss the role of HPV 16 E6 and E7 variants in metabolic reprogramming and their contribution to developing and preserving the malignant phenotype of cancers associated with HPV 16 infection.
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Affiliation(s)
- Adán Arizmendi-Izazaga
- Laboratorio de Biomedicina Molecular, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas S/N, Ciudad Universitaria, Colonia La Haciendita, Chilpancingo C.P. 39090, Guerrero, Mexico; (A.A.-I.); (M.A.M.-C.); (A.E.Z.-G.); (F.I.T.-R.); (D.G.S.-F.); (B.I.-A.)
| | - Napoleón Navarro-Tito
- Laboratorio de Biología Celular del Cáncer, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas S/N, Ciudad Universitaria, Colonia La Haciendita, Chilpancingo C.P. 39090, Guerrero, Mexico; (N.N.-T.); (M.O.-F.)
| | - Hilda Jiménez-Wences
- Laboratorio de Investigación en Biomoléculas, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas S/N, Ciudad Universitaria, Colonia La Haciendita, Chilpancingo C.P. 39090, Guerrero, Mexico; (H.J.-W.); (D.N.M.-C.)
- Laboratorio de Investigación Clínica, Facultad de Ciencias, Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas S/N, Ciudad Universitaria, Colonia La Haciendita, Chilpancingo C.P. 39090, Guerrero, Mexico;
| | - Miguel A. Mendoza-Catalán
- Laboratorio de Biomedicina Molecular, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas S/N, Ciudad Universitaria, Colonia La Haciendita, Chilpancingo C.P. 39090, Guerrero, Mexico; (A.A.-I.); (M.A.M.-C.); (A.E.Z.-G.); (F.I.T.-R.); (D.G.S.-F.); (B.I.-A.)
- Laboratorio de Investigación en Biomoléculas, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas S/N, Ciudad Universitaria, Colonia La Haciendita, Chilpancingo C.P. 39090, Guerrero, Mexico; (H.J.-W.); (D.N.M.-C.)
| | - Dinorah N. Martínez-Carrillo
- Laboratorio de Investigación en Biomoléculas, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas S/N, Ciudad Universitaria, Colonia La Haciendita, Chilpancingo C.P. 39090, Guerrero, Mexico; (H.J.-W.); (D.N.M.-C.)
- Laboratorio de Investigación Clínica, Facultad de Ciencias, Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas S/N, Ciudad Universitaria, Colonia La Haciendita, Chilpancingo C.P. 39090, Guerrero, Mexico;
| | - Ana E. Zacapala-Gómez
- Laboratorio de Biomedicina Molecular, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas S/N, Ciudad Universitaria, Colonia La Haciendita, Chilpancingo C.P. 39090, Guerrero, Mexico; (A.A.-I.); (M.A.M.-C.); (A.E.Z.-G.); (F.I.T.-R.); (D.G.S.-F.); (B.I.-A.)
| | - Monserrat Olea-Flores
- Laboratorio de Biología Celular del Cáncer, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas S/N, Ciudad Universitaria, Colonia La Haciendita, Chilpancingo C.P. 39090, Guerrero, Mexico; (N.N.-T.); (M.O.-F.)
| | - Roberto Dircio-Maldonado
- Laboratorio de Investigación Clínica, Facultad de Ciencias, Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas S/N, Ciudad Universitaria, Colonia La Haciendita, Chilpancingo C.P. 39090, Guerrero, Mexico;
- Laboratorio de Diagnóstico e Investigación en Salud, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas S/N, Ciudad Universitaria, Colonia La Haciendita, Chilpancingo C.P. 39090, Guerrero, Mexico
| | - Francisco I. Torres-Rojas
- Laboratorio de Biomedicina Molecular, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas S/N, Ciudad Universitaria, Colonia La Haciendita, Chilpancingo C.P. 39090, Guerrero, Mexico; (A.A.-I.); (M.A.M.-C.); (A.E.Z.-G.); (F.I.T.-R.); (D.G.S.-F.); (B.I.-A.)
| | - Diana G. Soto-Flores
- Laboratorio de Biomedicina Molecular, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas S/N, Ciudad Universitaria, Colonia La Haciendita, Chilpancingo C.P. 39090, Guerrero, Mexico; (A.A.-I.); (M.A.M.-C.); (A.E.Z.-G.); (F.I.T.-R.); (D.G.S.-F.); (B.I.-A.)
| | - Berenice Illades-Aguiar
- Laboratorio de Biomedicina Molecular, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas S/N, Ciudad Universitaria, Colonia La Haciendita, Chilpancingo C.P. 39090, Guerrero, Mexico; (A.A.-I.); (M.A.M.-C.); (A.E.Z.-G.); (F.I.T.-R.); (D.G.S.-F.); (B.I.-A.)
- Laboratorio de Diagnóstico e Investigación en Salud, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas S/N, Ciudad Universitaria, Colonia La Haciendita, Chilpancingo C.P. 39090, Guerrero, Mexico
| | - Julio Ortiz-Ortiz
- Laboratorio de Biomedicina Molecular, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas S/N, Ciudad Universitaria, Colonia La Haciendita, Chilpancingo C.P. 39090, Guerrero, Mexico; (A.A.-I.); (M.A.M.-C.); (A.E.Z.-G.); (F.I.T.-R.); (D.G.S.-F.); (B.I.-A.)
- Laboratorio de Investigación en Biomoléculas, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas S/N, Ciudad Universitaria, Colonia La Haciendita, Chilpancingo C.P. 39090, Guerrero, Mexico; (H.J.-W.); (D.N.M.-C.)
- Correspondence: ; Tel.: +52-747-471-0901
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Ho NTT, Rahane CS, Pramanik S, Kim PS, Kutzner A, Heese K. FAM72, Glioblastoma Multiforme (GBM) and Beyond. Cancers (Basel) 2021; 13:cancers13051025. [PMID: 33804473 PMCID: PMC7957592 DOI: 10.3390/cancers13051025] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 02/18/2021] [Accepted: 02/22/2021] [Indexed: 12/15/2022] Open
Abstract
Simple Summary Glioblastoma multiforme (GBM) is a serious and aggressive cancer disease that has not allowed scientists to rest for decades. In this review, we consider the new gene pair |-SRGAP2–FAM72-| and discuss its role in the cell cycle and the possibility of defining new therapeutic approaches for the treatment of GBM and other cancers via this gene pair |-SRGAP2–FAM72-|. Abstract Neural stem cells (NSCs) offer great potential for regenerative medicine due to their excellent ability to differentiate into various specialized cell types of the brain. In the central nervous system (CNS), NSC renewal and differentiation are under strict control by the regulation of the pivotal SLIT-ROBO Rho GTPase activating protein 2 (SRGAP2)—Family with sequence similarity 72 (FAM72) master gene (i.e., |-SRGAP2–FAM72-|) via a divergent gene transcription activation mechanism. If the gene transcription control unit (i.e., the intergenic region of the two sub-gene units, SRGAP2 and FAM72) gets out of control, NSCs may transform into cancer stem cells and generate brain tumor cells responsible for brain cancer such as glioblastoma multiforme (GBM). Here, we discuss the surveillance of this |-SRGAP2–FAM72-| master gene and its role in GBM, and also in light of FAM72 for diagnosing various types of cancers outside of the CNS.
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Affiliation(s)
- Nguyen Thi Thanh Ho
- Graduate School of Biomedical Science and Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 133-791, Korea;
| | - Chinmay Satish Rahane
- Maharashtra Institute of Medical Education and Research, Talegaon Dabhade, Maharashtra 410507, India;
| | - Subrata Pramanik
- Institute of Biotechnology, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany;
| | - Pok-Son Kim
- Department of Mathematics, Kookmin University, 77 Jeongneung-ro, Seongbuk-gu, Seoul 136-702, Korea;
| | - Arne Kutzner
- Department of Information Systems, College of Computer Science, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 133-791, Korea;
| | - Klaus Heese
- Graduate School of Biomedical Science and Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 133-791, Korea;
- Correspondence:
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Zargar ZU, Kimidi MR, Tyagi S. Dynamic site-specific recruitment of RBP2 by pocket protein p130 modulates H3K4 methylation on E2F-responsive promoters. Nucleic Acids Res 2019; 46:174-188. [PMID: 29059406 PMCID: PMC5758877 DOI: 10.1093/nar/gkx961] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 10/07/2017] [Indexed: 02/01/2023] Open
Abstract
The Histone 3 lysine 4 methylation (H3K4me3) mark closely correlates with active transcription. E2F-responsive promoters display dynamic changes in H3K4 methylation during the course of cell cycle progression. However, how and when these marks are reset, is not known. Here we show that the retinoblastoma binding protein RBP2/KDM5A, capable of removing tri-methylation marks on H3K4, associates with the E2F4 transcription factor via the pocket protein-p130-in a cell-cycle-stage specific manner. The association of RBP2 with p130 is LxCxE motif dependent. RNAi experiments reveal that p130 recruits RBP2 to E2F-responsive promoters in early G1 phase to bring about H3K4 demethylation and gene repression. A point mutation in LxCxE motif of RBP2 renders it incapable of p130-interaction and hence, repression of E2F-regulated gene promoters. We also examine how RBP2 may be recruited to non-E2F responsive promoters. Our studies provide insight into how the chromatin landscape needs to be adjusted rapidly and periodically during cell-cycle progression, concomitantly with temporal transcription, to bring about expression/repression of specific gene sets.
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Affiliation(s)
- Zaffer Ullah Zargar
- Laboratory of Cell Cycle Regulation, Centre for DNA Fingerprinting and Diagnostics (CDFD), Nampally, Hyderabad 500001, India.,Graduate Studies, Manipal University, Manipal, India
| | - Mallikharjuna Rao Kimidi
- Laboratory of Cell Cycle Regulation, Centre for DNA Fingerprinting and Diagnostics (CDFD), Nampally, Hyderabad 500001, India
| | - Shweta Tyagi
- Laboratory of Cell Cycle Regulation, Centre for DNA Fingerprinting and Diagnostics (CDFD), Nampally, Hyderabad 500001, India
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Pagano C, di Martino O, Ruggiero G, Maria Guarino A, Mueller N, Siauciunaite R, Reischl M, Simon Foulkes N, Vallone D, Calabrò V. The tumor-associated YB-1 protein: new player in the circadian control of cell proliferation. Oncotarget 2018; 8:6193-6205. [PMID: 28008157 PMCID: PMC5351623 DOI: 10.18632/oncotarget.14051] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 12/12/2016] [Indexed: 12/12/2022] Open
Abstract
Correct spatial and temporal control of cell proliferation is of fundamental importance for tissue homeostasis. Its deregulation has been associated with several pathological conditions. In common with almost every aspect of plant and animal biology, cell proliferation is dominated by day-night rhythms generated by the circadian clock. However, our understanding of the crosstalk between the core clock and cell cycle control mechanisms remains incomplete. In this study, using zebrafish as a vertebrate model system, we show that the nuclear localization of the Y-box binding protein 1 (YB-1), a regulator of cyclin expression and a hallmark of certain cancers, is robustly regulated by the circadian clock. We implicate clock-controlled changes in YB-1 SUMOylation as one of the mechanisms regulating its periodic nuclear entry at the beginning of the light phase. Furthermore, we demonstrate that YB-1 nuclear protein is able to downregulate cyclin A2 mRNA expression in zebrafish via its direct interaction with the cyclin A2 promoter. Thus, by acting as a direct target of cyclic posttranslational regulatory mechanisms, YB-1 serves as one bridge between the circadian clock and its cell cycle control.
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Affiliation(s)
- Cristina Pagano
- Institute of Toxicology and Genetics (ITG) Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Orsola di Martino
- Department of Biology, University of Naples "Federico II", 80126 Naples, Italy
| | - Gennaro Ruggiero
- Institute of Toxicology and Genetics (ITG) Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | | | - Nathalie Mueller
- Institute of Toxicology and Genetics (ITG) Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Rima Siauciunaite
- Institute of Toxicology and Genetics (ITG) Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Markus Reischl
- Institute for Applied Computer Science (IAI) Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Nicholas Simon Foulkes
- Institute of Toxicology and Genetics (ITG) Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Daniela Vallone
- Institute of Toxicology and Genetics (ITG) Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Viola Calabrò
- Department of Biology, University of Naples "Federico II", 80126 Naples, Italy
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Chang WH, Thai P, Xu J, Yang DC, Wu R, Chen CH. Cigarette Smoke Regulates the Competitive Interactions between NRF2 and BACH1 for Heme Oxygenase-1 Induction. Int J Mol Sci 2017; 18:ijms18112386. [PMID: 29125538 PMCID: PMC5713355 DOI: 10.3390/ijms18112386] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 10/31/2017] [Accepted: 11/08/2017] [Indexed: 11/17/2022] Open
Abstract
Cigarette smoke has been shown to trigger aberrant signaling pathways and pathophysiological processes; however, the regulatory mechanisms underlying smoke-induced gene expression remain to be established. Herein, we observed that two smoke-responsive genes, HO-1 and CYP1A1, are robustly induced upon smoke by different mechanisms in human bronchial epithelia. CYP1A1 is mediated by aryl hydrocarbon receptor signaling, while induction of HO-1 is regulated by oxidative stress, and suppressed by N-acetylcysteine treatment. In light of a pivotal role of NRF2 and BACH1 in response to oxidative stress and regulation of HO-1, we examined if smoke-induced HO-1 expression is modulated through the NRF2/BACH1 axis. We demonstrated that smoke causes significant nuclear translocation of NRF2, but only a slight decrease in nuclear BACH1. Knockdown of NRF2 attenuated smoke-induced HO-1 expression while down-regulation of BACH1 had stimulatory effects on both basal and smoke-induced HO-1 with trivial influence on NRF2 nuclear translocation. Chromatin immunoprecipitation assays showed that smoke augments promoter-specific DNA binding of NRF2 but suppresses BACH1 binding to the HO-1 promoter ARE sites, two of which at −1.0 kb and −2.6 kb are newly identified. These results suggest that the regulation of NRF2 activator and BACH1 repressor binding to the ARE sites are critical for smoke-mediated HO-1 induction.
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Affiliation(s)
- Wen-Hsin Chang
- Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine and Center for Comparative Respiratory Biology and Medicine, University of California Davis, Davis, CA 95616, USA.
- Institute of Molecular Medicine, National Taiwan University College of Medicine, Taipei 10002, Taiwan.
| | - Philip Thai
- Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine and Center for Comparative Respiratory Biology and Medicine, University of California Davis, Davis, CA 95616, USA.
| | - Jihao Xu
- Division of Nephrology, Department of Internal Medicine, University of California Davis, Davis, CA 95616, USA.
| | - David C Yang
- Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine and Center for Comparative Respiratory Biology and Medicine, University of California Davis, Davis, CA 95616, USA.
- Division of Nephrology, Department of Internal Medicine, University of California Davis, Davis, CA 95616, USA.
| | - Reen Wu
- Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine and Center for Comparative Respiratory Biology and Medicine, University of California Davis, Davis, CA 95616, USA.
| | - Ching-Hsien Chen
- Division of Nephrology, Department of Internal Medicine, University of California Davis, Davis, CA 95616, USA.
- Comprehensive Cancer Center, University of California Davis, Davis, CA 95616, USA.
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10
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Stelitano D, Peche LY, Dalla E, Monte M, Piazza S, Schneider C. GTSE1: a novel TEAD4-E2F1 target gene involved in cell protrusions formation in triple-negative breast cancer cell models. Oncotarget 2017; 8:67422-67438. [PMID: 28978043 PMCID: PMC5620183 DOI: 10.18632/oncotarget.18691] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 05/22/2017] [Indexed: 12/14/2022] Open
Abstract
GTSE1 over-expression has been reported as a potential marker for metastasis in various types of malignancies, including breast cancer. Despite this, the transcriptional regulation of this protein and the causes of its misregulation in tumors remain largely unknown. The aims of this work were to elucidate how GTSE1 is regulated at the transcriptional level and to clarify the mechanism underlying GTSE1-dependent cell functions in triple-negative breast cancer (TNBC). Here, we identified GTSE1 as a novel target gene of the TEAD4 transcription factor, highlighting a role for the YAP and TAZ coactivators in the transcriptional regulation of GTSE1. Moreover, we found that TEAD4 controls the formation of cell protrusions required for cell migration through GTSE1, unveiling a relevant effector role for this protein in the TEAD-dependent cellular functions and confirming TEAD4 role in promoting invasion and metastasis in breast cancer. Finally, we highlighted a role for the pRb-E2F1 pathway in the control of GTSE1 transcription and observed that treatment with drugs targeting the pRb-E2F1 or YAP/TAZ-TEAD pathways dramatically downregulated the expression levels of GTSE1 and of other genes involved in the formation of metastasis, suggesting their potential use in the treatment of TNBC.
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Affiliation(s)
- Debora Stelitano
- Laboratorio Nazionale del Consorzio Interuniversitario per le Biotecnologie (L.N.CIB), Trieste, Italy
| | - Leticia Yamila Peche
- Laboratorio Nazionale del Consorzio Interuniversitario per le Biotecnologie (L.N.CIB), Trieste, Italy
| | - Emiliano Dalla
- Laboratorio Nazionale del Consorzio Interuniversitario per le Biotecnologie (L.N.CIB), Trieste, Italy
| | - Martin Monte
- Laboratorio de Oncología Molecular, Departamento de Química Biológica and IQUIBICEN-UBA/CONICET, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Silvano Piazza
- Laboratorio Nazionale del Consorzio Interuniversitario per le Biotecnologie (L.N.CIB), Trieste, Italy.,Bioinformatics Core facility, Centre for Integrative Biology, University of Trento (CIBIO), Trento, Italy
| | - Claudio Schneider
- Laboratorio Nazionale del Consorzio Interuniversitario per le Biotecnologie (L.N.CIB), Trieste, Italy.,Dipartimento di Scienze Biomediche e Biologiche (DSMB), Università degli Studi di Udine, Udine, Italy
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11
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Genomic structure, expression pattern, and functional characterization of transcription factor E2F-2 from black tiger shrimp (Penaeus monodon). PLoS One 2017; 12:e0177420. [PMID: 28558060 PMCID: PMC5448752 DOI: 10.1371/journal.pone.0177420] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 04/26/2017] [Indexed: 01/10/2023] Open
Abstract
Transcription factor E2F-2 is a regulator of cell cycle. Researchers identified E2F-2 genes from yeasts to humans, but few reports investigated E2F-2 gene from black tiger shrimp. In the present study, we cloned E2F-2 gene from black tiger shrimp (Penaeus monodon). Full-length PmE2F-2 complementary DNA sequence measures 3,189 bp with an open reading frame of 1,371 bp. Complete PmE2F-2 genomic sequence (17,305 bp) of P. monodon contains nine exons, which are separated by eight introns. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis indicated that PmE2F-2 is highly expressed in hepatopancreas and ovaries of P. monodon. Highest PmE2F-2 expression levels were observed in stage III ovarian development of P. monodon. PmE2F-2 expression levels were significantly augmented in ovaries of P. monodon after 5-hydroxytryptamine injection and eyestalk ablation. RNA interference experiments were conducted to examine PmE2F-2, PmCDK2, and PmCyclin E expression profiles. PmE2F-2 was successfully knocked down in ovaries and hepatopancreas via double-stranded RNA (dsRNA)-E2F-2 injection. In the same organs, PmE2F-2 expression localization and level were investigated through in situ hybridization, which revealed consistent results with those of qRT-PCR. After dsRNA-E2F-2 injection, gonadosomatic index of shrimp was significantly lower than those following dsRNA-GFP and phosphate-buffered solution injections. Therefore, PmE2F-2 may be involved in ovarian maturation in P. monodon.
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12
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Jones RA, Robinson TJ, Liu JC, Shrestha M, Voisin V, Ju Y, Chung PED, Pellecchia G, Fell VL, Bae S, Muthuswamy L, Datti A, Egan SE, Jiang Z, Leone G, Bader GD, Schimmer A, Zacksenhaus E. RB1 deficiency in triple-negative breast cancer induces mitochondrial protein translation. J Clin Invest 2016; 126:3739-3757. [PMID: 27571409 DOI: 10.1172/jci81568] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 07/12/2016] [Indexed: 01/03/2023] Open
Abstract
Triple-negative breast cancer (TNBC) includes basal-like and claudin-low subtypes for which no specific treatment is currently available. Although the retinoblastoma tumor-suppressor gene (RB1) is frequently lost together with TP53 in TNBC, it is not directly targetable. There is thus great interest in identifying vulnerabilities downstream of RB1 that can be therapeutically exploited. Here, we determined that combined inactivation of murine Rb and p53 in diverse mammary epithelial cells induced claudin-low-like TNBC with Met, Birc2/3-Mmp13-Yap1, and Pvt1-Myc amplifications. Gene set enrichment analysis revealed that Rb/p53-deficient tumors showed elevated expression of the mitochondrial protein translation (MPT) gene pathway relative to tumors harboring p53 deletion alone. Accordingly, bioinformatic, functional, and biochemical analyses showed that RB1-E2F complexes bind to MPT gene promoters to regulate transcription and control MPT. Additionally, a screen of US Food and Drug Administration-approved (FDA-approved) drugs identified the MPT antagonist tigecycline (TIG) as a potent inhibitor of Rb/p53-deficient tumor cell proliferation. TIG preferentially suppressed RB1-deficient TNBC cell proliferation, targeted both the bulk and cancer stem cell fraction, and strongly attenuated xenograft growth. It also cooperated with sulfasalazine, an FDA-approved inhibitor of cystine xCT antiporter, in culture and xenograft assays. Our results suggest that RB1 deficiency promotes cancer cell proliferation in part by enhancing mitochondrial function and identify TIG as a clinically approved drug for RB1-deficient TNBC.
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13
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Mitxelena J, Apraiz A, Vallejo-Rodríguez J, Malumbres M, Zubiaga AM. E2F7 regulates transcription and maturation of multiple microRNAs to restrain cell proliferation. Nucleic Acids Res 2016; 44:5557-5570. [PMID: 26961310 PMCID: PMC4937299 DOI: 10.1093/nar/gkw146] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
E2F transcription factors (E2F1-8) are known to coordinately regulate the expression of a plethora of target genes, including those coding for microRNAs (miRNAs), to control cell cycle progression. Recent work has described the atypical E2F factor E2F7 as a transcriptional repressor of cell cycle-related protein-coding genes. However, the contribution of E2F7 to miRNA gene expression during the cell cycle has not been defined. We have performed a genome-wide RNA sequencing analysis to identify E2F7-regulated miRNAs and show that E2F7 plays as a major role in the negative regulation of a set of miRNAs that promote cellular proliferation. We provide mechanistic evidence for an interplay between E2F7 and the canonical E2F factors E2F1-3 in the regulation of multiple miRNAs. We show that miR-25, -26a, -27b, -92a and -7 expression is controlled at the transcriptional level by the antagonistic activity of E2F7 and E2F1-3. By contrast, let-7 miRNA expression is controlled indirectly through a novel E2F/c-MYC/LIN28B axis, whereby E2F7 and E2F1-3 modulate c-MYC and LIN28B levels to impact let-7 miRNA processing and maturation. Taken together, our data uncover a new regulatory network involving transcriptional and post-transcriptional mechanisms controlled by E2F7 to restrain cell cycle progression through repression of proliferation-promoting miRNAs.
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Affiliation(s)
- Jone Mitxelena
- Department of Genetics, Physical Anthropology and Animal Physiology, University of the Basque Country UPV/EHU, 48080 Bilbao, Spain
| | - Aintzane Apraiz
- Department of Cell Biology and Histology, University of the Basque Country UPV/EHU, 48080 Bilbao, Spain
| | - Jon Vallejo-Rodríguez
- Department of Genetics, Physical Anthropology and Animal Physiology, University of the Basque Country UPV/EHU, 48080 Bilbao, Spain
| | - Marcos Malumbres
- Cell Division and Cancer Group, Spanish National Cancer Research Centre (CNIO), 28029 Madrid, Spain
| | - Ana M Zubiaga
- Department of Genetics, Physical Anthropology and Animal Physiology, University of the Basque Country UPV/EHU, 48080 Bilbao, Spain
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14
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De Leonardis F, Monti L, Gualeni B, Tenni R, Forlino A, Rossi A. Altered signaling in the G1 phase deregulates chondrocyte growth in a mouse model with proteoglycan undersulfation. J Cell Biochem 2015; 115:1779-86. [PMID: 24820054 PMCID: PMC4262066 DOI: 10.1002/jcb.24844] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 05/09/2014] [Indexed: 12/15/2022]
Abstract
In several skeletal dysplasias defects in extracellular matrix molecules affect not only the structural and mechanical properties of cartilage, but also the complex network of signaling pathways involved in cell proliferation and differentiation. Sulfated proteoglycans, besides playing an important structural role in cartilage, are crucial in modulating the transport, diffusion, and interactions of growth factors with their specific targets, taking part in the regulation of signaling pathways involved in skeletal development and growth. In this work, we investigated by real time PCR and Western blots of the microdissected growth plate and by immunohistochemistry the molecular basis of reduced chondrocyte proliferation in the growth plate of the dtd mouse, a chondrodysplastic model with defective chondroitin sulfate proteoglycan sulfation of articular and growth plate cartilage. We detected activation of the Wnt pathway, leading to an increase in the non-phosphorylated form of nuclear β-catenin and subsequent up-regulation of cyclin D1 expression in the G1 phase of the cell cycle. β-Catenin was further stabilized by up-regulation of Smad3 expression through TGF-β pathway synergistic activation. We demonstrate that notwithstanding cyclin D1 expression increase, cell cycle progression is compromised in the G1 phase due to reduced phosphorylation of the pocket protein p130 leading to inhibition of transcription factors of the E2F family which are crucial for cell cycle progression and DNA replication. These data, together with altered Indian hedgehox signaling detected previously, explain at the molecular level the reduced chondrocyte proliferation rate of the dtd growth plate leading to reduced skeletal growth. J. Cell. Biochem. 115: 1779–1786, 2014.
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Affiliation(s)
- Fabio De Leonardis
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Pavia, Italy
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15
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Yeh HH, Tseng YF, Hsu YC, Lan SH, Wu SY, Raghavaraju G, Cheng DE, Lee YR, Chang TY, Chow NH, Hung WC, Liu HS. Ras induces experimental lung metastasis through up-regulation of RbAp46 to suppress RECK promoter activity. BMC Cancer 2015; 15:172. [PMID: 25885317 PMCID: PMC4377201 DOI: 10.1186/s12885-015-1155-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 03/02/2015] [Indexed: 12/30/2022] Open
Abstract
Background Mutant Ras plays multiple functions in tumorigenesis including tumor formation and metastasis. Reversion-inducing cysteine-rich protein with Kazal motifs (RECK), a metastasis inhibitor gene, suppresses matrix metalloproteinase (MMP) activity in the metastatic cascade. Clarifying the relationship between Ras and RECK and understanding the underlying molecular mechanism may lead to the development of better treatment for Ras-related tumors. Methods Suppression subtractive hybridization PCR (SSH PCR) was conducted to identify Ha-rasval12 up-regulated genes in bladder cancer cells. Stable cell lines of human breast cancer (MCF-7-ras) and mouse NIH3T3 fibroblasts (7–4) harboring the inducible Ha-rasval12 oncogene, which could be induced by isopropylthio-β-D-galactoside (IPTG), were used to clarify the relationship between Ras and the up-regulated genes. Chromatin immunoprecipitation (ChIP) assay, DNA affinity precipitation assay (DAPA) and RECK reporter gene assay were utilized to confirm the complex formation and binding with promoters. Results Retinoblastoma binding protein-7 (RbAp46) was identified and confirmed as a Ha-rasval12 up-regulated gene. RbAp46 could bind with histone deacetylase (HDAC1) and Sp1, followed by binding to RECK promoter at the Sp1 site resulting in repression of RECK expression. High expression of Ras protein accompanied with high RbAp46 and low RECK expression were detected in 75% (3/4) of the clinical bladder cancer tumor tissues compared to the adjacent normal parts. Ras induced RbAp46 expression increases invasion of the bladder cancer T24 cells and MMP-9 activity was increased, which was confirmed by specific lentiviral shRNAs inhibitors against Ras and RbAp46. Similarly, knockdown of RbAp46 expression in the stable NIH3T3 cells “7-4” by shRNA decreased Ras-related lung metastasis using a xenograft nude mice model. Conclusions We confirmed that RbAp46 is a Ha-rasval12 up-regulated gene and binds with HDAC1 and Sp1. Furthermore, RbAp46 binds to the RECK promoter at the Sp1 site via recruitment by Sp1. RECK is subsequently activated, leading to increased MMP9 activity, which may lead to increased metastasis in vivo. Our findings of Ras upregulation of RbAp46 may lead to revealing a novel mechanism of Ras-related tumor cell metastasis. Electronic supplementary material The online version of this article (doi:10.1186/s12885-015-1155-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hsuan-Heng Yeh
- Department of Microbiology and Immunology, National Cheng Kung University, Tainan, Taiwan. .,Institute of Basic Medical Sciences, National Cheng Kung University, Tainan, Taiwan.
| | - Yu-Fen Tseng
- Department of Microbiology and Immunology, National Cheng Kung University, Tainan, Taiwan.
| | - Yu-Chiao Hsu
- Department of Microbiology and Immunology, National Cheng Kung University, Tainan, Taiwan.
| | - Sheng-Hui Lan
- Department of Microbiology and Immunology, National Cheng Kung University, Tainan, Taiwan. .,Institute of Basic Medical Sciences, National Cheng Kung University, Tainan, Taiwan.
| | - Shan-Ying Wu
- Department of Microbiology and Immunology, National Cheng Kung University, Tainan, Taiwan. .,Institute of Basic Medical Sciences, National Cheng Kung University, Tainan, Taiwan.
| | - Giri Raghavaraju
- Department of Microbiology and Immunology, National Cheng Kung University, Tainan, Taiwan.
| | - Da-En Cheng
- Department of Microbiology and Immunology, National Cheng Kung University, Tainan, Taiwan.
| | - Ying-Ray Lee
- Department of Medical Research, Chiayi Christian Hospital, Chiayi, Taiwan.
| | - Tsuey-Yu Chang
- Department of Parasitology, National Cheng Kung University, Tainan, Taiwan.
| | - Nan-Haw Chow
- Department of Pathology, National Cheng Kung University, Tainan, Taiwan.
| | - Wen-Chun Hung
- Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan. .,National Institute of Cancer Research, National Health Research Institutes, Tainan, Taiwan.
| | - Hsiao-Sheng Liu
- Department of Microbiology and Immunology, National Cheng Kung University, Tainan, Taiwan. .,Institute of Basic Medical Sciences, National Cheng Kung University, Tainan, Taiwan. .,Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan.
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16
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E2F activators signal and maintain centrosome amplification in breast cancer cells. Mol Cell Biol 2014; 34:2581-99. [PMID: 24797070 DOI: 10.1128/mcb.01688-13] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Centrosomes ensure accurate chromosome segregation by directing spindle bipolarity. Loss of centrosome regulation results in centrosome amplification, multipolar mitosis and aneuploidy. Since centrosome amplification is common in premalignant lesions and breast tumors, it is proposed to play a central role in breast tumorigenesis, a hypothesis that remains to be tested. The coordination between the cell and centrosome cycles is of paramount importance to maintain normal centrosome numbers, and the E2Fs may be responsible for regulating these cycles. However, the role of E2F activators in centrosome amplification is unclear. Because E2Fs are deregulated in Her2(+) cells displaying centrosome amplification, we addressed whether they signal this abnormal process. Knockdown of E2F1 or E2F3 in Her2(+) cells decreased centrosome amplification without significantly affecting cell cycle progression, whereas the overexpression of E2F1, E2F2, or E2F3 increased centrosome amplification in MCF10A mammary epithelial cells. Our results revealed that E2Fs affect the expression of proteins, including Nek2 and Plk4, known to influence the cell/centrosome cycles and mitosis. Downregulation of E2F3 resulted in cell death and delays/blocks in cytokinesis, which was reversed by Nek2 overexpression. Nek2 overexpression enhanced centrosome amplification in Her2(+) breast cancer cells silenced for E2F3, revealing a role for the E2F activators in maintaining centrosome amplification in part through Nek2.
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17
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Toki H, Inoue M, Minowa O, Motegi H, Saiki Y, Wakana S, Masuya H, Gondo Y, Shiroishi T, Yao R, Noda T. Novel retinoblastoma mutation abrogating the interaction to E2F2/3, but not E2F1, led to selective suppression of thyroid tumors. Cancer Sci 2014; 105:1360-8. [PMID: 25088905 PMCID: PMC4462357 DOI: 10.1111/cas.12495] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 07/18/2014] [Accepted: 07/25/2014] [Indexed: 01/18/2023] Open
Abstract
Mutant mouse models are indispensable tools for clarifying gene functions and elucidating the pathogenic mechanisms of human diseases. Here, we describe novel cancer models bearing point mutations in the retinoblastoma gene (Rb1) generated by N-ethyl-N-nitrosourea mutagenesis. Two mutations in splice sites reduced Rb1 expression and led to a tumor spectrum and incidence similar to those observed in the conventional Rb1 knockout mice. The missense mutant, Rb1D326V/+, developed pituitary tumors, but thyroid tumors were completely suppressed. Immunohistochemical analyses of thyroid tissue revealed that E2F1, but not E2F2/3, was selectively inactivated, indicating that the mutant Rb protein (pRb) suppressed thyroid tumors by inactivating E2F1. Interestingly, Rb1D326V/+ mice developed pituitary tumors that originated from the intermediate lobe of the pituitary, despite selective inactivation of E2F1. Furthermore, in the anterior lobe of the pituitary, other E2F were also inactivated. These observations show that pRb mediates the inactivation of E2F function and its contribution to tumorigenesis is highly dependent on the cell type. Last, by using a reconstitution assay of synthesized proteins, we showed that the D326V missense pRb bound to E2F1 but failed to interact with E2F2/3. These results reveal the effect of the pRb N-terminal domain on E2F function and the impact of the protein on tumorigenesis. Thus, this mutant mouse model can be used to investigate human Rb family-bearing mutations at the N-terminal region.
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Affiliation(s)
- Hideaki Toki
- Team for Advanced Development and Evaluation of Human Disease Models, Riken BioResource Center, Tsukuba, Ibaraki, Japan
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18
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Li J, Gao JZ, Du JL, Huang ZX, Wei LX. Increased CDC20 expression is associated with development and progression of hepatocellular carcinoma. Int J Oncol 2014; 45:1547-55. [PMID: 25069850 DOI: 10.3892/ijo.2014.2559] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 04/22/2014] [Indexed: 11/05/2022] Open
Abstract
Cell division cycle 20 (CDC20) encodes a regulatory protein interacting with the anaphase-promoting complex/cyclosome (APC/C) in the cell cycle and plays important roles in tumorigenesis and progression of multiple tumors. The present study aimed to investigate the clinical significance of CDC20 in hepatocellular carcinoma (HCC) and the role of CDC20 in the progression of HCC. By bioinformatics analysis, CDC20 was found to be the major node in HCC molecular interaction networks. Quantitative PCR and western blot analyses were applied to examine CDC20 expression in 16 paired primary HCC tissues. Immunohistochemistry (IHC) was performed to examine CDC20 protein expression in 132 matched paraffin-embedded HCC tissues and to analyze the relationship between CDC20 staining and clinical characteristics. Small interfering RNA (siRNA) targeting CDC20 was synthesized and transfected into HepG2 cells to investigate the role of CDC20 in cell growth and the cell cycle. Results show that CDC20 expression was upregulated in HCC tissues compared to adjacent non-tumor liver tissues. In the 132 matched HCC tissues, high expression levels of CDC20 were detected in 68.18% HCC samples, and overexpression of CDC20 was positively correlated with gender (P=0.013), tumor differentiation (P=0.000), TNM stage (P=0.012), P53 and Ki-67 expression (P=0.023 and P=0.007, respectively). Cells transfected with CDC20 siRNA showed a decrease in cell proliferation and increase in the number of cells in G2/M-phase. In conclusion, increased expression of CDC20 was demonstrated to be associated with the development and progression of HCC, and may be regarded as a promising therapeutic target for HCC.
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Affiliation(s)
- Jia Li
- Department of Pathology, Chinese PLA General Hospital, Beijing 100853, P.R. China
| | - Jian-Zhi Gao
- Department of Pathology, Chinese PLA General Hospital, Beijing 100853, P.R. China
| | - Jing-Li Du
- Department of Pathology, Chinese PLA General Hospital, Beijing 100853, P.R. China
| | - Zhong-Xi Huang
- Cancer Institute, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Li-Xin Wei
- Department of Pathology, Chinese PLA General Hospital, Beijing 100853, P.R. China
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19
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Abstract
Mammalian DREAM is a conserved protein complex that functions in cellular quiescence. DREAM contains an E2F, a retinoblastoma (RB)-family protein, and the MuvB core (LIN9, LIN37, LIN52, LIN54, and RBBP4). In mammals, MuvB can alternatively bind to BMYB to form a complex that promotes mitotic gene expression. Because BMYB-MuvB is essential for proliferation, loss-of-function approaches to study MuvB have generated limited insight into DREAM function. Here, we report a gene-targeted mouse model that is uniquely deficient for DREAM complex assembly. We have targeted p107 (Rbl1) to prevent MuvB binding and combined it with deficiency for p130 (Rbl2). Our data demonstrate that cells from these mice preferentially assemble BMYB-MuvB complexes and fail to repress transcription. DREAM-deficient mice show defects in endochondral bone formation and die shortly after birth. Micro-computed tomography and histology demonstrate that in the absence of DREAM, chondrocytes fail to arrest proliferation. Since DREAM requires DYRK1A (dual-specificity tyrosine phosphorylation-regulated protein kinase 1A) phosphorylation of LIN52 for assembly, we utilized an embryonic bone culture system and pharmacologic inhibition of (DYRK) kinase to demonstrate a similar defect in endochondral bone growth. This reveals that assembly of mammalian DREAM is required to induce cell cycle exit in chondrocytes.
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20
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Lu Z, Bauzon F, Fu H, Cui J, Zhao H, Nakayama K, Nakayama KI, Zhu L. Skp2 suppresses apoptosis in Rb1-deficient tumours by limiting E2F1 activity. Nat Commun 2014; 5:3463. [PMID: 24632684 PMCID: PMC3982150 DOI: 10.1038/ncomms4463] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 02/18/2014] [Indexed: 02/07/2023] Open
Abstract
One mechanism of tumor suppression by pRb is repressing E2F1. Hence, E2f1 deletion diminishes tumorigenesis following Rb1 loss. However, E2F1 promotes both proliferation and apoptosis. It therefore remains unclear how de-repressed E2F1 promotes tumorigenesis. Another mechanism of pRb function is repressing Skp2 to elevate p27 to arrest proliferation. However, Skp2 deletion induced apoptosis, not proliferation arrest, in Rb1 deficient pituitary tumorigenesis. Here, we show that Rb1 deletion induces higher expression of E2F1 target genes in the absence of Skp2. E2F1 binds less cyclin A but more target promoters when Rb1 is deleted with Skp2 knockout or p27T187A knockin, suggesting that stabilized p27 prevents cyclin A from binding and inhibiting E2F1. In Rb1 deficient pituitary tumorigenesis, Skp2 deletion or p27T187A mutation converts E2F1’s role from proliferative to apoptotic. These findings delineate a pRb-Skp2-p27-cyclin A-E2F1 pathway that determines whether E2F1 is proliferative or apoptotic in Rb1 deficient tumorigenesis.
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Affiliation(s)
- Zhonglei Lu
- Department of Developmental and Molecular Biology and Ophthalmology and Visual Sciences and Medicine, The Albert Einstein Comprehensive Cancer Center and Liver Research Center, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Frederick Bauzon
- Department of Developmental and Molecular Biology and Ophthalmology and Visual Sciences and Medicine, The Albert Einstein Comprehensive Cancer Center and Liver Research Center, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Hao Fu
- Department of Developmental and Molecular Biology and Ophthalmology and Visual Sciences and Medicine, The Albert Einstein Comprehensive Cancer Center and Liver Research Center, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Jinhua Cui
- Department of Developmental and Molecular Biology and Ophthalmology and Visual Sciences and Medicine, The Albert Einstein Comprehensive Cancer Center and Liver Research Center, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Hongling Zhao
- Department of Developmental and Molecular Biology and Ophthalmology and Visual Sciences and Medicine, The Albert Einstein Comprehensive Cancer Center and Liver Research Center, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Keiko Nakayama
- Division of Cell Proliferation, ART, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Keiich I Nakayama
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Liang Zhu
- Department of Developmental and Molecular Biology and Ophthalmology and Visual Sciences and Medicine, The Albert Einstein Comprehensive Cancer Center and Liver Research Center, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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E2F1 coregulates cell cycle genes and chromatin components during the transition of oligodendrocyte progenitors from proliferation to differentiation. J Neurosci 2014; 34:1481-93. [PMID: 24453336 DOI: 10.1523/jneurosci.2840-13.2014] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Cell cycle exit is an obligatory step for the differentiation of oligodendrocyte progenitor cells (OPCs) into myelinating cells. A key regulator of the transition from proliferation to quiescence is the E2F/Rb pathway, whose activity is highly regulated in physiological conditions and deregulated in tumors. In this paper we report a lineage-specific decline of nuclear E2F1 during differentiation of rodent OPC into oligodendrocytes (OLs) in developing white matter tracts and in cultured cells. Using chromatin immunoprecipitation (ChIP) and deep-sequencing in mouse and rat OPCs, we identified cell cycle genes (i.e., Cdc2) and chromatin components (i.e., Hmgn1, Hmgn2), including those modulating DNA methylation (i.e., Uhrf1), as E2F1 targets. Binding of E2F1 to chromatin on the gene targets was validated and their expression assessed in developing white matter tracts and cultured OPCs. Increased expression of E2F1 gene targets was also detected in mouse gliomas (that were induced by retroviral transformation of OPCs) compared with normal brain. Together, these data identify E2F1 as a key transcription factor modulating the expression of chromatin components in OPC during the transition from proliferation to differentiation.
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p53-dependent gene repression through p21 is mediated by recruitment of E2F4 repression complexes. Oncogene 2013; 33:3959-69. [PMID: 24096481 PMCID: PMC4067464 DOI: 10.1038/onc.2013.378] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 07/03/2013] [Accepted: 07/12/2013] [Indexed: 02/06/2023]
Abstract
The p53 tumor suppressor protein is a major sensor of cellular stresses, and upon stabilization, activates or represses many genes that control cell fate decisions. While the mechanism of p53-mediated transactivation is well established, several mechanisms have been proposed for p53-mediated repression. Here, we demonstrate that the cyclin-dependent kinase inhibitor p21 is both necessary and sufficient for the downregulation of known p53-repression targets, including survivin, CDC25C, and CDC25B in response to p53 induction. These same targets are similarly repressed in response to p16 overexpression, implicating the involvement of the shared downstream retinoblastoma (RB)-E2F pathway. We further show that in response to either p53 or p21 induction, E2F4 complexes are specifically recruited onto the promoters of these p53-repression targets. Moreover, abrogation of E2F4 recruitment via the inactivation of RB pocket proteins, but not by RB loss of function alone, prevents the repression of these genes. Finally, our results indicate that E2F4 promoter occupancy is globally associated with p53-repression targets, but not with p53 activation targets, implicating E2F4 complexes as effectors of p21-dependent p53-mediated repression.
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23
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Garcia-Jove Navarro M, Basset C, Arcondéguy T, Touriol C, Perez G, Prats H, Lacazette E. Api5 contributes to E2F1 control of the G1/S cell cycle phase transition. PLoS One 2013; 8:e71443. [PMID: 23940755 PMCID: PMC3737092 DOI: 10.1371/journal.pone.0071443] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2011] [Accepted: 07/05/2013] [Indexed: 02/02/2023] Open
Abstract
Background The E2f transcription factor family has a pivotal role in controlling the cell fate in general, and in particular cancer development, by regulating the expression of several genes required for S phase entry and progression through the cell cycle. It has become clear that the transcriptional activation of at least one member of the family, E2F1, can also induce apoptosis. An appropriate balance of positive and negative regulators appears to be necessary to modulate E2F1 transcriptional activity, and thus cell fate. Methodology/Principal Findings In this report, we show that Api5, already known as a regulator of E2F1 induced-apoptosis, is required for the E2F1 transcriptional activation of G1/S transition genes, and consequently, for cell cycle progression and cell proliferation. Api5 appears to be a cell cycle regulated protein. Removal of Api5 reduces cyclin E, cyclin A, cyclin D1 and Cdk2 levels, causing G1 cell cycle arrest and cell cycle delay. Luciferase assays established that Api5 directly regulates the expression of several G1/S genes under E2F1 control. Using protein/protein and protein/DNA immunoprecipitation studies, we demonstrate that Api5, even if not physically interacting with E2F1, contributes positively to E2F1 transcriptional activity by increasing E2F1 binding to its target promoters, through an indirect mechanism. Conclusion/Significance The results described here support the pivotal role of cell cycle related proteins, that like E2F1, may act as tumor suppressors or as proto-oncogenes during cancer development, depending on the behavior of their positive and negative regulators. According to our findings, Api5 contributes to E2F1 transcriptional activation of cell cycle-associated genes by facilitating E2F1 recruitment onto its target promoters and thus E2F1 target gene transcription.
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Affiliation(s)
| | - Céline Basset
- INSERM UMR 1037, Cancer Research Center of Toulouse (CRCT), Cancer Department, Toulouse, France
| | - Tania Arcondéguy
- INSERM UMR 1037, Cancer Research Center of Toulouse (CRCT), Cancer Department, Toulouse, France
| | - Christian Touriol
- INSERM UMR 1037, Cancer Research Center of Toulouse (CRCT), Cancer Department, Toulouse, France
| | - Guillaume Perez
- INSERM UMR 1037, Cancer Research Center of Toulouse (CRCT), Cancer Department, Toulouse, France
| | - Hervé Prats
- INSERM UMR 1037, Cancer Research Center of Toulouse (CRCT), Cancer Department, Toulouse, France
| | - Eric Lacazette
- INSERM UMR 1037, Cancer Research Center of Toulouse (CRCT), Cancer Department, Toulouse, France
- * E-mail:
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24
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Abstract
The cell cycle ensures genome maintenance by coordinating the processes of DNA replication and chromosome segregation. Of particular importance is the irreversible transition from the G1 phase of the cell cycle to S phase. This transition marks the switch from preparing chromosomes for replication ("origin licensing") to active DNA synthesis ("origin firing"). Ubiquitin-mediated proteolysis is essential for restricting DNA replication to only once per cell cycle and is the major mechanism regulating the G1 to S phase transition. Although some changes in protein levels are attributable to regulated mRNA abundance, protein degradation elicits very rapid changes in protein abundance and is critical for the sharp and irreversible transition from one cell cycle stage to the next. Not surprisingly, regulation of the G1-to-S phase transition is perturbed in most cancer cells, and deregulation of key molecular events in G1 and S phase drives not only cell proliferation but also genome instability. In this review we focus on the mechanisms by which E3 ubiquitin ligases control the irreversible transition from G1 to S phase in mammalian cells.
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Affiliation(s)
- Lindsay F Rizzardi
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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25
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Overexpression of Cdk6 and Ccnd1 in chondrocytes inhibited chondrocyte maturation and caused p53-dependent apoptosis without enhancing proliferation. Oncogene 2013; 33:1862-71. [PMID: 23624920 DOI: 10.1038/onc.2013.130] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 02/21/2013] [Accepted: 03/04/2013] [Indexed: 12/21/2022]
Abstract
Cell proliferation and differentiation are closely coupled. However, we previously showed that overexpression of cyclin-dependent kinase (Cdk6) blocks chondrocyte differentiation without affecting cell-cycle progression in vitro. To investigate whether Cdk6 inhibits chondrocyte differentiation in vivo, we generated chondrocyte-specific Cdk6 transgenic mice using Col2a1 promoter. Unexpectedly, differentiation and cell-cycle progression of chondrocytes in the Cdk6 transgenic mice were similar to those in wild-type mice. Then, we generated chondrocyte-specific Ccnd1 transgenic mice and Cdk6/Ccnd1 double transgenic mice to investigate the possibility that Cdk6 inhibits chondrocyte differentiation through E2f activation. Bromodeoxyuridine (BrdU)-positive chondrocytes and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive chondrocytes were increased in number, and chondrocyte maturation was inhibited only in Cdk6/Ccnd1 transgenic mice (K6(H)/D1(H) mice), which showed dwarfism. Retinoblastoma protein (pRb) was highly phosphorylated but p107 was upregulated, and the expression of E2f target genes was dysregulated as shown by upregulation of Cdc6 but downregulation of cyclin E, dihydrofolate reductase (dhfr), Cdc25a and B-Myb in chondrocytes of K6(H)/D1(H) mice. Similarly, overexpression of Cdk6/Ccnd1 in a chondrogenic cell line ATDC5 highly phosphorylated pRb, upregulated p107, induced apoptosis, upregulated Cdc6 and downregulated cyclin E, dhfr and B-Myb and p107 small interfering RNA reversed the expression of downregulated genes. Further, introduction of kinase-negative Cdk6 and cyclin D1 abolished all effects by Cdk6/cyclin D1 in ATDC5 cells, indicating the requirement of the kinase activity on these effects. p53 deletion partially restored the size of the skeleton and almost completely rescued chondrocyte apoptosis, but failed to enhance chondrocyte proliferation in K6(H)/D1(H) mice. These findings indicated that Cdk6/Ccnd1 overexpression inhibited chondrocyte maturation and enhanced G1/S cell-cycle transition by phosphorylating pRb, but the chondrocytes failed to accomplish the cell cycle, and underwent p53-dependent apoptosis probably due to the dysregulation of E2f target genes. Our findings also indicated that p53 deletion in addition to the inactivation of Rb was not sufficient to accelerate chondrocyte proliferation, suggesting the resistance of chondrocytes to sarcomagenesis.
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26
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Control of glutamine metabolism by the tumor suppressor Rb. Oncogene 2013; 33:556-66. [PMID: 23353822 PMCID: PMC3918885 DOI: 10.1038/onc.2012.635] [Citation(s) in RCA: 155] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 11/16/2012] [Accepted: 11/30/2012] [Indexed: 12/15/2022]
Abstract
Retinoblastoma (Rb) protein is a tumor suppressor that is dysregulated in a majority of human cancers. Rb functions to inhibit cell cycle progression in part by directly disabling the E2F family of cell cycle-promoting transcription factors. Because the de novo synthesis of multiple glutamine-derived anabolic precursors is required for cell cycle progression, we hypothesized that Rb also may directly regulate proteins involved in glutamine metabolism. We examined glutamine metabolism in mouse embryonic fibroblasts (MEFs) isolated from mice that have triple knock-outs (TKO) of all three Rb family members (Rb-1, Rbl1, and Rbl2) and found that loss of global Rb function caused a marked increase in 13C-glutamine uptake and incorporation into glutamate and TCA cycle intermediates in part via upregulated expression of the glutamine transporter ASCT2 and the activity of glutaminase 1 (GLS1). The Rb-controlled transcription factor E2F-3 altered glutamine uptake by direct regulation of ASCT2 mRNA and protein expression, and E2F-3 was observed to associate with the ASCT2 promoter. We next examined the functional consequences of the observed increase in glutamine uptake and utilization and found that glutamine exposure potently increased oxygen consumption whereas glutamine deprivation selectively decreased ATP concentration in the Rb TKO MEFs but not the WT MEFs. In addition, TKO MEFs exhibited elevated production of glutathione from exogenous glutamine, and had increased expression of gamma-glutamylcysteine ligase relative to WT MEFs. Importantly, this metabolic shift towards glutamine utilization was required for the proliferation of Rb TKO MEFs but not for the proliferation of the WT MEFs. Last, addition of the TCA cycle intermediate α-ketoglutarate to the Rb TKO MEFs reversed the inhibitory effects of glutamine deprivation on ATP, GSH levels, and viability. Taken together, these studies demonstrate that the Rb/E2F cascade directly regulates a major energetic and anabolic pathway that is required for neoplastic growth.
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27
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Raj N, Zhang L, Wei Y, Arnosti DN, Henry RW. Ubiquitination of retinoblastoma family protein 1 potentiates gene-specific repression function. J Biol Chem 2012; 287:41835-43. [PMID: 23086928 DOI: 10.1074/jbc.m112.422428] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The retinoblastoma (RB) tumor suppressor family functions as a regulatory node governing cell cycle progression, differentiation, and apoptosis. Post-translational modifications play a critical role in modulating RB activity, but additional levels of control, including protein turnover, are also essential for proper function. The Drosophila RB homolog Rbf1 is subjected to developmentally cued proteolysis mediated by an instability element (IE) present in the C terminus of this protein. Paradoxically, instability mediated by the IE is also linked to Rbf1 repression potency, suggesting that proteolytic machinery may also be directly involved in transcriptional repression. We show that the Rbf1 IE is an autonomous degron that stimulates both Rbf1 ubiquitination and repression potency. Importantly, Rbf1 IE function is promoter-specific, contributing to repression of cell cycle responsive genes but not to repression of cell signaling genes. The multifunctional IE domain thus provides Rbf1 flexibility for discrimination between target genes embedded in divergent cellular processes.
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Affiliation(s)
- Nitin Raj
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824-1319, USA
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28
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Whitfield TW, Wang J, Collins PJ, Partridge EC, Aldred SF, Trinklein ND, Myers RM, Weng Z. Functional analysis of transcription factor binding sites in human promoters. Genome Biol 2012; 13:R50. [PMID: 22951020 PMCID: PMC3491394 DOI: 10.1186/gb-2012-13-9-r50] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2011] [Revised: 04/19/2012] [Accepted: 06/18/2012] [Indexed: 12/19/2022] Open
Abstract
Background The binding of transcription factors to specific locations in the genome is integral to the orchestration of transcriptional regulation in cells. To characterize transcription factor binding site function on a large scale, we predicted and mutagenized 455 binding sites in human promoters. We carried out functional tests on these sites in four different immortalized human cell lines using transient transfections with a luciferase reporter assay, primarily for the transcription factors CTCF, GABP, GATA2, E2F, STAT, and YY1. Results In each cell line, between 36% and 49% of binding sites made a functional contribution to the promoter activity; the overall rate for observing function in any of the cell lines was 70%. Transcription factor binding resulted in transcriptional repression in more than a third of functional sites. When compared with predicted binding sites whose function was not experimentally verified, the functional binding sites had higher conservation and were located closer to transcriptional start sites (TSSs). Among functional sites, repressive sites tended to be located further from TSSs than were activating sites. Our data provide significant insight into the functional characteristics of YY1 binding sites, most notably the detection of distinct activating and repressing classes of YY1 binding sites. Repressing sites were located closer to, and often overlapped with, translational start sites and presented a distinctive variation on the canonical YY1 binding motif. Conclusions The genomic properties that we found to associate with functional TF binding sites on promoters -- conservation, TSS proximity, motifs and their variations -- point the way to improved accuracy in future TFBS predictions.
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Affiliation(s)
- Troy W Whitfield
- Program in Bioinformatics and Integrative Biology and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
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29
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Kastner S, Voss T, Keuerleber S, Glöckel C, Freissmuth M, Sommergruber W. Expression of G protein-coupled receptor 19 in human lung cancer cells is triggered by entry into S-phase and supports G(2)-M cell-cycle progression. Mol Cancer Res 2012; 10:1343-58. [PMID: 22912338 DOI: 10.1158/1541-7786.mcr-12-0139] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
It has long been known that G protein-coupled receptors (GPCR) are subject to illegitimate expression in tumor cells. Presumably, hijacking the normal physiologic functions of GPCRs contributes to all biologic capabilities acquired during tumorigenesis. Here, we searched for GPCRs that were expressed in lung cancer: the mRNA encoding orphan G protein-coupled receptor 19 (GPR19) was found frequently overexpressed in tissue samples obtained from patients with small cell lung cancer. Several observations indicate that overexpression of Gpr19 confers a specific advantage to lung cancer cells by accelerating transition through the cell-cycle. (i) Knockdown of Gpr19 mRNA by RNA interference reduced cell growth of human lung cancer cell lines. (ii) Cell-cycle progression through G(2)-M-phase was impaired in cells transfected with siRNAs directed against Gpr19 and this was associated with increased protein levels of cyclin B1 and phosphorylated histone H3. (iii) The expression levels of Gpr19 mRNA varied along the cell-cycle with a peak observed in S-phase. (iv) The putative control of Gpr19 expression by E2F transcription factors was verified by chromatin immunoprecipitation: antibodies directed against E2F-1 to -4 allowed for the recovery of the Gpr19 promoter. (v) Removal of E2F binding sites in the Gpr19 promoter diminished the expression of a luciferase reporter. (vi) E2f and Gpr19 expression correlated in lung cancer patient samples. To the best of knowledge, this is the first example of a GPCR showing cell-cycle-specific mRNA expression. Our data also validate GPR19 as a candidate target when overexpressed in lung cancer.
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Affiliation(s)
- Stefan Kastner
- Boehringer Ingelheim RCV GmbH & Co KG, Department of Lead Discovery, Dr. Boehringer-Gasse 5-11, 1121 Vienna, Austria
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30
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The retinoblastoma family of proteins and their regulatory functions in the mammalian cell division cycle. Cell Div 2012; 7:10. [PMID: 22417103 PMCID: PMC3325851 DOI: 10.1186/1747-1028-7-10] [Citation(s) in RCA: 188] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 03/14/2012] [Indexed: 12/15/2022] Open
Abstract
The retinoblastoma (RB) family of proteins are found in organisms as distantly related as humans, plants, and insects. These proteins play a key role in regulating advancement of the cell division cycle from the G1 to S-phases. This is achieved through negative regulation of two important positive regulators of cell cycle entry, E2F transcription factors and cyclin dependent kinases. In growth arrested cells transcriptional activity by E2Fs is repressed by RB proteins. Stimulation of cell cycle entry by growth factor signaling leads to activation of cyclin dependent kinases. They in turn phosphorylate and inactivate the RB family proteins, leading to E2F activation and additional cyclin dependent kinase activity. This propels the cell cycle irreversibly forward leading to DNA synthesis. This review will focus on the basic biochemistry and cell biology governing the regulation and activity of mammalian RB family proteins in cell cycle control.
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31
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Yeo HC, Beh TT, Quek JJL, Koh G, Chan KKK, Lee DY. Integrated transcriptome and binding sites analysis implicates E2F in the regulation of self-renewal in human pluripotent stem cells. PLoS One 2011; 6:e27231. [PMID: 22076139 PMCID: PMC3208628 DOI: 10.1371/journal.pone.0027231] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 10/12/2011] [Indexed: 11/18/2022] Open
Abstract
Rapid cellular growth and multiplication, limited replicative senescence, calibrated sensitivity to apoptosis, and a capacity to differentiate into almost any cell type are major properties that underline the self-renewal capabilities of human pluripotent stem cells (hPSCs). We developed an integrated bioinformatics pipeline to understand the gene regulation and functions involved in maintaining such self-renewal properties of hPSCs compared to matched fibroblasts. An initial genome-wide screening of transcription factor activity using in silico binding-site and gene expression microarray data newly identified E2F as one of major candidate factors, revealing their significant regulation of the transcriptome. This is underscored by an elevated level of its transcription factor activity and expression in all tested pluripotent stem cell lines. Subsequent analysis of functional gene groups demonstrated the importance of the TFs to self-renewal in the pluripotency-coupled context; E2F directly targets the global signaling (e.g. self-renewal associated WNT and FGF pathways) and metabolic network (e.g. energy generation pathways, molecular transports and fatty acid metabolism) to promote its canonical functions that are driving the self-renewal of hPSCs. In addition, we proposed a core self-renewal module of regulatory interplay between E2F and, WNT and FGF pathways in these cells. Thus, we conclude that E2F plays a significant role in influencing the self-renewal capabilities of hPSCs.
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Affiliation(s)
- Hock Chuan Yeo
- Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Thian Thian Beh
- Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Jovina Jia Ling Quek
- Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore, Singapore
| | - Geoffrey Koh
- Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Ken Kwok Keung Chan
- Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- * E-mail: (KKKC); (DYL)
| | - Dong-Yup Lee
- Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore, Singapore
- * E-mail: (KKKC); (DYL)
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32
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Yao X, Shan S, Zhang Y, Ying H. Recent progress in the study of brown adipose tissue. Cell Biosci 2011; 1:35. [PMID: 22035495 PMCID: PMC3219668 DOI: 10.1186/2045-3701-1-35] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Accepted: 10/28/2011] [Indexed: 01/11/2023] Open
Abstract
Brown adipose tissue in mammals plays a critical role in maintaining energy balance by thermogenesis, which means dissipating energy in the form of heat. It is held that in mammals, long-term surplus food intake results in energy storage in the form of triglyceride and may eventually lead to obesity. Stimulating energy-dissipating function of brown adipose tissue in human body may counteract fat accumulation. In order to utilize brown adipose tissue as a therapeutic target, the mechanisms underlying brown adipocyte differentiation and function should be better elucidated. Here we review the molecular mechanisms involved in brown adipose tissue development and thermogenesis, and share our thoughts on current challenges and possible future therapeutic approaches.
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Affiliation(s)
- Xuan Yao
- Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.
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33
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Abstract
The transcription factor B-Myb plays a critical role in regulating gene expression and is implicated in controlling carcinogenesis and cellular senescence. Transcription of the B-Myb gene is regulated by retinoblastoma proteins acting directly on the B-Myb promoter. Recently, we found that microRNAs also control the abundance of B-Myb mRNA during senescence, adding another level of complexity to B-Myb regulation. This review focuses on the importance of B-Myb in cancer and senescence, with an emphasis on the regulation of B-Myb expression and activity.
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Affiliation(s)
- Ivan Martinez
- Department of Genetics and Yale Comprehensive Cancer Center, Yale School of Medicine, New Haven, Connecticut 06520-8005, USA
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34
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Delgado I, Fresnedo O, Iglesias A, Rueda Y, Syn WK, Zubiaga AM, Ochoa B. A role for transcription factor E2F2 in hepatocyte proliferation and timely liver regeneration. Am J Physiol Gastrointest Liver Physiol 2011; 301:G20-31. [PMID: 21527726 DOI: 10.1152/ajpgi.00481.2010] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
E2F transcription factors are key regulators of the cell cycle although the relative contribution of each E2F member in regulating cellular proliferation is still poorly defined. Present evidence suggests that E2F2 may act both as a suppressor and promoter of proliferation, depending on the cellular context. We used a loss-of-function mutant mouse model to investigate the function of E2F2 in liver regeneration after partial hepatectomy, a paradigm of cell-cycle progression. Liver mass recovery and histology were examined over 9 days in 70% hepatectomized E2F2(-/-) and wild-type animals. Transcriptome analysis was performed in quiescent and 48-h regenerating liver samples. TIGR MultiExperiment Viewer was used for the statistical analysis of microarray data, significance was determined by Fischer, and P values were adjusted applying Benjamini-Hochberg multiple-testing correction. We show that E2F2 is required for adult hepatocyte proliferation and for timely liver regeneration, as disruption of the E2F2 gene in hepatocytes leads to a reduced rate of S-phase entry and to delayed liver regeneration. Transcriptome analysis followed by ontological classification of differentially expressed genes and gene-interaction network analysis indicated that the majority of genes involved in normal liver regeneration were related to biosynthetic and catabolic processes of all major biomolecules as well as cellular location and intracellular transport, confirming the complex nature of the regeneration process. Remarkably, transcripts of genes included in functional categories that are crucial for cell cycle, apoptosis and wound-healing response, and fibrosis were absent in the transcriptome of posthepatectomized E2F2(-/-) mice. Our results indicate that the transcriptional activity of E2F2 contributes to promote adult hepatocyte proliferation and liver regeneration.
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Affiliation(s)
- Igotz Delgado
- Departments of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country, Sarriena s/n, Leioa, Spain
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35
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Miller ES, Berman SD, Yuan TL, Lees JA. Disruption of calvarial ossification in E2f4 mutant embryos correlates with increased proliferation and progenitor cell populations. Cell Cycle 2011; 9:2620-8. [PMID: 20581455 DOI: 10.4161/cc.9.13.12108] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The E2F family of transcription factors, in association with pocket protein family members, are important for regulating genes required for cellular proliferation. The most abundant E2F, E2F4, is implicated in maintaining the G(0)/G(1) cell cycle state via transcriptional repression of genes that encode proteins required for S-phase progression. Here, we investigate E2F4's role in bone development using E2f4 germline mutant mice. We find that mutation of E2f4 impairs the formation of several bones that arise through intramembranous or endochondral ossification. The most severe defect occurred in the calvarial bones of the skull where we observed a striking delay in their ossification. In vivo and in vitro analyses established that E2F4 loss did not block the intrinsic differentiation potential of calvarial osteoblast progenitors. However, our data showed that E2f4 mutation elevated proliferation in the developing calvaria in vivo and it increased the endogenous pool of undifferentiated progenitor cells. These data suggest that E2F4 plays an important role in enabling osteoblast progenitors to exit the cell cycle and subsequently differentiate thereby contributing to the commitment of these cells to the bone lineage.
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Affiliation(s)
- Emily S Miller
- David H. Koch Institute for Integrative Cancer Research, MIT, Cambridge, MA, USA
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36
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Yang XP, Ghoreschi K, Steward-Tharp SM, Rodriguez-Canales J, Zhu J, Grainger JR, Hirahara K, Sun HW, Wei L, Vahedi G, Kanno Y, O’Shea JJ, Laurence A. Opposing regulation of the locus encoding IL-17 through direct, reciprocal actions of STAT3 and STAT5. Nat Immunol 2011; 12:247-54. [PMID: 21278738 PMCID: PMC3182404 DOI: 10.1038/ni.1995] [Citation(s) in RCA: 481] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Accepted: 01/11/2011] [Indexed: 12/12/2022]
Abstract
Interleukin 2 (IL-2), a cytokine linked to human autoimmune disease, limits IL-17 production. Here we found that deletion of the gene encoding the transcription factor STAT3 in T cells abrogated IL-17 production and attenuated autoimmunity associated with IL-2 deficiency. Whereas STAT3 induced IL-17 and the transcription factor RORγt and inhibited the transcription factor Foxp3, IL-2 inhibited IL-17 independently of Foxp3 and RORγt. STAT3 and STAT5 bound to multiple common sites across the locus encoding IL-17. The induction of STAT5 binding by IL-2 was associated with less binding of STAT3 at these sites and the inhibition of associated active epigenetic marks. 'Titration' of the relative activation of STAT3 and STAT5 modulated the specification of cells to the IL-17-producing helper T cell (T(H)17 cell) subset. Thus, the balance rather than the absolute magnitude of these signals determined the propensity of cells to make a key inflammatory cytokine.
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Affiliation(s)
- Xiang-Ping Yang
- Molecular Immunology and Inflammation Branch, National Institute of Arthritis, Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kamran Ghoreschi
- Molecular Immunology and Inflammation Branch, National Institute of Arthritis, Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Scott M. Steward-Tharp
- Molecular Immunology and Inflammation Branch, National Institute of Arthritis, Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jaime Rodriguez-Canales
- Laser Capture Microdissection Core Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jinfang Zhu
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - John R. Grainger
- Mucosal immunology section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kiyoshi Hirahara
- Molecular Immunology and Inflammation Branch, National Institute of Arthritis, Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Hong-Wei Sun
- Molecular Immunology and Inflammation Branch, National Institute of Arthritis, Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Lai Wei
- Clinical Immunology Section, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Golnaz Vahedi
- Molecular Immunology and Inflammation Branch, National Institute of Arthritis, Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yuka Kanno
- Molecular Immunology and Inflammation Branch, National Institute of Arthritis, Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - John J. O’Shea
- Molecular Immunology and Inflammation Branch, National Institute of Arthritis, Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Arian Laurence
- Molecular Immunology and Inflammation Branch, National Institute of Arthritis, Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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37
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Furrer M, Balbi M, Albarca-Aguilera M, Gallant M, Herr W, Gallant P. Drosophila Myc interacts with host cell factor (dHCF) to activate transcription and control growth. J Biol Chem 2010; 285:39623-36. [PMID: 20937797 PMCID: PMC3000943 DOI: 10.1074/jbc.m110.140467] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Revised: 09/08/2010] [Indexed: 01/14/2023] Open
Abstract
The Myc proto-oncoproteins are transcription factors that recognize numerous target genes through hexameric DNA sequences called E-boxes. The mechanism by which they then activate the expression of these targets is still under debate. Here, we use an RNAi screen in Drosophila S2 cells to identify Drosophila host cell factor (dHCF) as a novel co-factor for Myc that is functionally required for the activation of a Myc-dependent reporter construct. dHCF is also essential for the full activation of endogenous Myc target genes in S2 cells, and for the ability of Myc to promote growth in vivo. Myc and dHCF physically interact, and they colocalize on common target genes. Furthermore, down-regulation of dHCF-associated histone acetyltransferase and histone methyltransferase complexes in vivo interferes with the Myc biological activities. We therefore propose that dHCF recruits such chromatin-modifying complexes and thereby contributes to the expression of Myc targets and hence to the execution of Myc biological activities.
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Affiliation(s)
- Michael Furrer
- From the Zoologisches Institut, Universität Zürich, 8057 Zürich, Switzerland and
| | - Mirjam Balbi
- From the Zoologisches Institut, Universität Zürich, 8057 Zürich, Switzerland and
| | - Monica Albarca-Aguilera
- the Center for Integrative Genomics (CIG), University of Lausanne, 1015 Lausanne, Switzerland
| | - Maria Gallant
- From the Zoologisches Institut, Universität Zürich, 8057 Zürich, Switzerland and
| | - Winship Herr
- the Center for Integrative Genomics (CIG), University of Lausanne, 1015 Lausanne, Switzerland
| | - Peter Gallant
- From the Zoologisches Institut, Universität Zürich, 8057 Zürich, Switzerland and
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38
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Li W, Ni GX, Zhang P, Zhang ZX, Li W, Wu Q. Characterization of E2F3a function in HepG2 liver cancer cells. J Cell Biochem 2010; 111:1244-51. [DOI: 10.1002/jcb.22851] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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39
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Cyclin-dependent kinase 2 (CDK-2) expression in nonmelanocytic human cutaneous lesions. Appl Immunohistochem Mol Morphol 2010; 18:357-64. [PMID: 20216405 DOI: 10.1097/pai.0b013e3181d4069c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Lesions originating from different types of skin cells differ significantly with respect to their pathologic importance. The aim of this work was to examine as to what extent the differences in the origin are reflected in expression levels of CDK-2 and to investigate whether CDK-2 expression might be considered as potential marker useful for diagnostics and assessment of invasiveness of human nonmelanocytic lesions. We conducted comparative immunohistochemical studies of expression of cyclin-dependent kinase 2 (CDK-2) in 16 benign epithelial skin lesions, 11 precancerous lesions, 19 cases of basal cell carcinoma (first such study), 14 squamous cell carcinomas (SCCs), and 7 fibromas. Development of benign epithelial skin lesions was not associated with considerable increase of the CDK-2 expression. Increase of the CDK-2 level was observed in precancerous lesions, and the expression was strongest in SCCs. The level of CDK-2 may be related to invasiveness of skin cancers, as squamous cell carcinomas expressed the enzyme significantly stronger than basal cell carcinomas. Higher percentage fraction of CDK-2 positive cells observed in SCC compared with precancerous lesions may be useful for histopathologic diagnostics of this cancer. Moreover, strong immunohistochemical CDK-2 staining of the cancer cells present deep in dermis may facilitate their detection in histopathologic examinations.
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40
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Singh S, Johnson J, Chellappan S. Small molecule regulators of Rb-E2F pathway as modulators of transcription. BIOCHIMICA ET BIOPHYSICA ACTA 2010; 1799:788-94. [PMID: 20637913 PMCID: PMC2997897 DOI: 10.1016/j.bbagrm.2010.07.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 06/24/2010] [Accepted: 07/08/2010] [Indexed: 12/25/2022]
Abstract
The retinoblastoma tumor suppressor protein, Rb, plays a major role in the regulation of mammalian cell cycle progression. It has been shown that Rb function is essential for the proper modulation of G1/S transition and inactivation of Rb contributes to deregulated cell proliferation. Rb exerts its cell cycle regulatory functions mainly by targeting the E2F family of transcription factors and Rb has been shown to physically interact with E2Fs 1, 2 and 3, repressing their transcriptional activity. Multiple genes involved in DNA synthesis and cell cycle progression are regulated by E2Fs, and Rb prevents their expression by inhibiting E2F activity, inducing growth arrest. It has been established that inactivation of Rb by phosphorylation, mutation, or by the interaction of viral oncoproteins leads to a release of the repression of E2F activity, facilitating cell cycle progression. Rb-mediated repression of E2F activity involves the recruitment of a variety of transcriptional co-repressors and chromatin remodeling proteins, including histone deacetylases, DNA methyltransferases and Brg1/Brm chromatin remodeling proteins. Inactivation of Rb by sequential phosphorylation events during cell cycle progression leads to a dissociation of these co-repressors from Rb, facilitating transcription. It has been found that small molecules that prevent the phosphorylation of Rb prevent the dissociation of certain co-repressors from Rb, especially Brg1, leading to the maintenance of Rb-mediated transcriptional repression and cell cycle arrest. Such small molecules have anti-cancer activities and will also act as valuable probes to study chromatin remodeling and transcriptional regulation.
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Affiliation(s)
- Sandeep Singh
- Drug Discovery Program, H. Lee Moffitt Cancer Center and Research Institute, 12902 Magnolia Drive, Tampa, FL 33612
| | - Jackie Johnson
- Drug Discovery Program, H. Lee Moffitt Cancer Center and Research Institute, 12902 Magnolia Drive, Tampa, FL 33612
| | - Srikumar Chellappan
- Drug Discovery Program, H. Lee Moffitt Cancer Center and Research Institute, 12902 Magnolia Drive, Tampa, FL 33612
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41
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Delston RB, Matatall KA, Sun Y, Onken MD, Harbour JW. p38 phosphorylates Rb on Ser567 by a novel, cell cycle-independent mechanism that triggers Rb-Hdm2 interaction and apoptosis. Oncogene 2010; 30:588-99. [PMID: 20871633 PMCID: PMC3012146 DOI: 10.1038/onc.2010.442] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The retinoblastoma protein (Rb) inhibits both cell division and apoptosis, but the mechanism by which Rb alternatively regulates these divergent outcomes remains poorly understood. Cyclin dependent kinases (Cdks) promote cell division by phosphorylating and reversibly inactivating Rb by a hierarchical series of phosphorylation events and sequential conformational changes. The stress-regulated mitogen activated protein kinase (MAPK) p38 also phosphorylates Rb, but it does so in a cell cycle-independent manner that is associated with apoptosis rather than with cell division. Here, we show that p38 phosphorylates Rb by a novel mechanism that is distinct from that of Cdks. p38 bypasses the cell cycle-associated hierarchical phosphorylation and directly phosphorylates Rb on Ser567, which is not phosphorylated during the normal cell cycle. Phosphorylation by p38, but not Cdks, triggers an interaction between Rb and the human homologue of murine double minute 2 (Hdm2), leading to degradation of Rb, release of E2F1 and cell death. These findings provide a mechanistic explanation for how Rb regulates cell division and apoptosis through different kinases, and reveal how Hdm2 may functionally link the tumor suppressors Rb and p53.
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Affiliation(s)
- R B Delston
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St Louis, MO, USA
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42
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Chromatin loading of E2F-MLL complex by cancer-associated coregulator ANCCA via reading a specific histone mark. Mol Cell Biol 2010; 30:5260-72. [PMID: 20855524 DOI: 10.1128/mcb.00484-10] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Histone modifications are regarded as the carrier of epigenetic memory through cell divisions. How the marks facilitate cell cycle-dependent gene expression is poorly understood. The evolutionarily conserved AAA ATPase ANCCA (AAA nuclear coregulator cancer-associated protein)/ATAD2 was identified as a direct target of oncogene AIB1/ACTR/SRC-3 and a transcriptional coregulator for estrogen and androgen receptors and is strongly implicated in tumorigenesis. We report here that ANCCA directly interacts with E2F1 to E2F3 and that its N terminus interacts with both the N and C termini of E2F1. ANCCA preferentially associates via its bromodomain with H3 acetylated at lysine 14 (H3K14ac) and is required for key cell cycle gene expression and cancer cell proliferation. ANCCA associates with chromosomes at late mitosis, and its occupancy at E2F targets peaks at the G(1)-to-S transition. Strikingly, ANCCA is required for recruitment of specific E2Fs to their targets and chromatin assembly of the host cell factor 1 (HCF-1)-MLL histone methyltransferase complex. ANCCA depletion results in a marked decrease of the gene activation-linked H3K4me3 mark. Bromodomain mutations disable ANCCA function as an E2F coactivator and its ability to promote cancer cell proliferation, while ANCCA overexpression in tumors correlates with tumor growth. Together, these results suggest that ANCCA acts as a pioneer factor in E2F-dependent gene activation and that a novel mechanism involving ANCCA bromodomain may contribute to cancer cell proliferation.
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43
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Golubev A. Random discrete competing events vs. dynamic bistable switches in cell proliferation in differentiation. J Theor Biol 2010; 267:341-54. [PMID: 20816686 DOI: 10.1016/j.jtbi.2010.08.032] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Revised: 08/27/2010] [Accepted: 08/27/2010] [Indexed: 12/25/2022]
Abstract
Several recent experiments related to fundamental aspects of cell behaviour, such as passing of the restriction point of cell cycle, which are generally interpreted in accordance with the dynamic paradigm implying the use of differential equations operating with the concentrations of cellular components and rate constants of their interactions, are shown in the present paper to be consistent with a simple model based on discrete competing stochastic events interpreted as assembly of alternative complexes of transcription factors at gene promoters. The model conforms to the transition probability model of cell cycle and to the stochastic approaches to cell differentiation and integrates them with the restriction point concept.
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Affiliation(s)
- A Golubev
- Research Institute for Experimental Medicine, Saint-Petersburg, Russia.
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44
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Chicas A, Wang X, Zhang C, McCurrach M, Zhao Z, Mert O, Dickins RA, Narita M, Zhang M, Lowe SW. Dissecting the unique role of the retinoblastoma tumor suppressor during cellular senescence. Cancer Cell 2010; 17:376-87. [PMID: 20385362 PMCID: PMC2889489 DOI: 10.1016/j.ccr.2010.01.023] [Citation(s) in RCA: 292] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Revised: 12/31/2009] [Accepted: 02/17/2010] [Indexed: 12/29/2022]
Abstract
The RB protein family (RB, p107, and p130) has overlapping and compensatory functions in cell-cycle control. However, cancer-associated mutations are almost exclusively found in RB, implying that RB has a nonredundant role in tumor suppression. We demonstrate that RB preferentially associates with E2F target genes involved in DNA replication and is uniquely required to repress these genes during senescence but not other growth states. Consequently, RB loss leads to inappropriate DNA synthesis following a senescence trigger and, together with disruption of a p21-mediated cell-cycle checkpoint, enables extensive proliferation and rampant genomic instability. Our results identify a nonredundant RB effector function that may contribute to tumor suppression and reveal how loss of RB and p53 cooperate to bypass senescence.
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Affiliation(s)
- Agustin Chicas
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Xiaowo Wang
- MOE Key Laboratory of Bioinformatics and Bioinformatics Div, TNLIST/Department of Automation, Tsinghua University, Beijing 100084, China
| | - Chaolin Zhang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Mila McCurrach
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Zhen Zhao
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Ozlem Mert
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Ross A. Dickins
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Masashi Narita
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Michael Zhang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Scott W. Lowe
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
- Howard Hughes Medical Institute, Cold Spring Harbor, NY 11724, USA
- To whom correspondence should be addressed, Contact information: Scott W. Lowe, Ph.D., Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor NY 11724, Phone: 516-367-8406,
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45
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Swiss VA, Casaccia P. Cell-context specific role of the E2F/Rb pathway in development and disease. Glia 2010; 58:377-90. [PMID: 19795505 DOI: 10.1002/glia.20933] [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]
Abstract
Development of the central nervous system (CNS) requires the generation of neuronal and glial cell subtypes in appropriate numbers, and this demands the careful coordination of cell-cycle exit, survival, and differentiation. The E2F/Rb pathway is critical for cell-cycle regulation and also modulates survival and differentiation of distinct cell types in the developing and adult CNS. In this review, we first present the specific temporal patterns of expression of the E2F and Rb family members during CNS development and then discuss the genetic ablation of single or multiple members of these two families. Overall, the available data suggest a time-dependent and cell-context specific role of E2F and Rb family members in the developing and adult CNS.
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Affiliation(s)
- Victoria A Swiss
- Department of Neuroscience and Genetics and Genomics, Mount Sinai School of Medicine, New York, New York 10029, USA
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46
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Sahin F, Sladek TL. E2F-1 has dual roles depending on the cell cycle. Int J Biol Sci 2010; 6:116-28. [PMID: 20224733 PMCID: PMC2836542 DOI: 10.7150/ijbs.6.116] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2009] [Accepted: 02/28/2010] [Indexed: 02/03/2023] Open
Abstract
The E2F family of transcription factors play a critical role in the control of cell proliferation. E2F-1 is the major cellular target of pRB and is regulated by pRB during cell proliferation. E2F-1-mediated activation and repression of target genes occurs in different settings. The role of E2F-1 and E2F-1/pRB complexes in regulation of different target genes, and in cycling versus quiescent cells, is unclear. In this study, effects of free E2F-1 (doesn't complex with pRb) and E2F-1/pRb complex, on E2F-1 target gene expression were compared in different cell growth conditions. Findings suggest that E2F-1 acts in different ways, not only depending on the target gene but also depending on different stages of the cell cycle. For example, E2F-1 acts as part of the repression complex with pRB in the expression of DHFR, b-myb, TK and cdc2 in asynchronously growing cells; on the other hand, E2F-1 acts as an activator in the expression of the same genes in cells that are re-entering the cycle.
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Affiliation(s)
- Fikret Sahin
- Department of Microbiology and Immunology, Finch University of Health Sciences/Chicago Medical School (now Rosalind Franklin University), 3333 Green Bay Road, North Chicago, Illinois 60064-3095, USA.
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47
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Jiménez-Lara AM, Aranda A, Gronemeyer H. Retinoic acid protects human breast cancer cells against etoposide-induced apoptosis by NF-kappaB-dependent but cIAP2-independent mechanisms. Mol Cancer 2010; 9:15. [PMID: 20102612 PMCID: PMC2825243 DOI: 10.1186/1476-4598-9-15] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Accepted: 01/26/2010] [Indexed: 11/10/2022] Open
Abstract
Background Retinoids, through their cognate nuclear receptors, exert potent effects on cell growth, differentiation and apoptosis, and have significant promise for cancer therapy and chemoprevention. These ligands can determine the ultimate fate of target cells by stimulating or repressing gene expression directly, or indirectly through crosstalking with other signal transducers. Results Using different breast cancer cell models, we show here that depending on the cellular context retinoids can signal either towards cell death or cell survival. Indeed, retinoids can induce the expression of pro-apoptotic (i.e. TRAIL, TNF-Related Apoptosis-Inducing Ligand, Apo2L/TNFSF10) and anti-apoptotic (i.e. cIAP2, inhibitor of apoptosis protein-2) genes. Promoter mapping, gel retardation and chromatin immunoprecipitation assays revealed that retinoids induce the expression of this gene mainly through crosstalk with NF-kappaB. Supporting this crosstalk, the activation of NF-kappaB by retinoids in T47D cells antagonizes the apoptosis triggered by the chemotherapeutic drugs etoposide, camptothecin or doxorubicin. Notably apoptosis induced by death ligands (i.e. TRAIL or antiFAS) is not antagonized by retinoids. That knockdown of cIAP2 expression by small interfering RNA does not alter the inhibition of etoposide-induced apoptosis by retinoids in T47D cells reveals that stimulation of cIAP2 expression is not the cause of their anti-apoptotic action. However, ectopic overexpression of a NF-kappaB repressor increases apoptosis by retinoids moderately and abrogates almost completely the retinoid-dependent inhibition of etoposide-induced apoptosis. Our data exclude cIAP2 and suggest that retinoids target other regulator(s) of the NF-kappaB signaling pathway to induce resistance to etoposide on certain breast cancer cells. Conclusions This study shows an important role for the NF-kappaB pathway in retinoic acid signaling and retinoic acid-mediated resistance to cancer therapy-mediated apoptosis in breast cancer cells, independently of cIAP2. Our data support the use of NF-kappaB pathway activation as a marker for screening that will help to develop novel retinoids, or retinoid-based combination therapies with improved efficacy.
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Affiliation(s)
- Ana M Jiménez-Lara
- Instituto de Investigaciones Biomédicas de Madrid Alberto Sols, CSIC/UAM, Madrid, Spain.
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48
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Müller GA, Engeland K. The central role of CDE/CHR promoter elements in the regulation of cell cycle-dependent gene transcription. FEBS J 2009; 277:877-93. [PMID: 20015071 DOI: 10.1111/j.1742-4658.2009.07508.x] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The cell cycle-dependent element (CDE) and the cell cycle genes homology region (CHR) control the transcription of genes with maximum expression in G(2) phase and in mitosis. Promoters of these genes are repressed by proteins binding to CDE/CHR elements in G(0) and G(1) phases. Relief from repression begins in S phase and continues into G(2) phase and mitosis. Generally, CDE sites are located four nucleotides upstream of CHR elements in TATA-less promoters of genes such as Cdc25C, Cdc2 and cyclin A. However, expression of some other genes, such as human cyclin B1 and cyclin B2, has been shown to be controlled only by a CHR lacking a functional CDE. To date, it is not fully understood which proteins bind to and control CDE/CHR-containing promoters. Recently, components of the DREAM complex were shown to be involved in CDE/CHR-dependent transcriptional regulation. In addition, the expression of genes regulated by CDE/CHR elements is mostly achieved through CCAAT-boxes, which bind heterotrimeric NF-Y proteins as well as the histone acetyltransferase p300. Importantly, many CDE/CHR promoters are downregulated by the tumor suppressor p53. In this review, we define criteria for CDE/CHR-regulated promoters and propose to distinguish two classes of CDE/CHR-regulated genes. The regulation through transcription factors potentially binding to the CDE/CHR is discussed, and recently discovered links to central pathways regulated by E2F, the pRB family and p53 are highlighted.
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Affiliation(s)
- Gerd A Müller
- Molecular Oncology, Department of Obstetrics and Gynecology, University of Leipzig, Germany
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49
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TAp63 induces senescence and suppresses tumorigenesis in vivo. Nat Cell Biol 2009; 11:1451-7. [PMID: 19898465 DOI: 10.1038/ncb1988] [Citation(s) in RCA: 194] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Accepted: 10/19/2009] [Indexed: 12/14/2022]
Abstract
p63 is distinct from its homologue p53 in that its role as a tumour suppressor is controversial, an issue complicated by the existence of two classes of p63 isoforms. Here we show that TAp63 isoforms are robust mediators of senescence that inhibit tumorigenesis in vivo. Whereas gain of TAp63 induces senescence, loss of p63 enhances sarcoma development in mice lacking p53. Using a new TAp63-specific conditional mouse model, we demonstrate that TAp63 isoforms are essential for Ras-induced senescence, and that TAp63 deficiency increases proliferation and enhances Ras-mediated oncogenesis in the context of p53 deficiency in vivo. TAp63 induces senescence independently of p53, p19(Arf) and p16(Ink4a), but requires p21(Waf/Cip1) and Rb. TAp63-mediated senescence overrides Ras-driven transformation of p53-deficient cells, preventing tumour initiation, and doxycycline-regulated expression of TAp63 activates p21(Waf/Cip1), induces senescence and inhibits progression of established tumours in vivo. Our findings demonstrate that TAp63 isoforms function as tumour suppressors by regulating senescence through p53-independent pathways. The ability of TAp63 to trigger senescence and halt tumorigenesis irrespective of p53 status identifies TAp63 as a potential target of anti-cancer therapy for human malignancies with compromised p53.
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50
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Abstract
Mutations of the retinoblastoma tumour suppressor gene (RB1) or components regulating the RB pathway have been identified in almost every human malignancy. The E2F transcription factors function in cell cycle control and are intimately regulated by RB. Studies of model organisms have revealed conserved functions for E2Fs during development, suggesting that the cancer-related proliferative roles of E2F family members represent a recent evolutionary adaptation. However, given that some human tumours have concurrent RB1 inactivation and E2F amplification and overexpression, we propose that there are alternative tumour-promoting activities for the E2F family, which are independent of cell cycle regulation.
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Affiliation(s)
- Hui-Zi Chen
- Human Cancer Genetics Program, Department of Molecular Virology, Immunology and Medical Genetics and Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210, USA
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