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Karasu ME, Jahnke L, Joseph BJ, Amerzhanova Y, Mironov A, Shu X, Schröder MS, Gvozdenovic A, Sala I, Zavolan M, Jonas S, Corn JE. CCAR1 promotes DNA repair via alternative splicing. Mol Cell 2024; 84:2634-2647.e9. [PMID: 38964321 DOI: 10.1016/j.molcel.2024.06.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 04/29/2024] [Accepted: 06/12/2024] [Indexed: 07/06/2024]
Abstract
DNA repair is directly performed by hundreds of core factors and indirectly regulated by thousands of others. We massively expanded a CRISPR inhibition and Cas9-editing screening system to discover factors indirectly modulating homology-directed repair (HDR) in the context of ∼18,000 individual gene knockdowns. We focused on CCAR1, a poorly understood gene that we found the depletion of reduced both HDR and interstrand crosslink repair, phenocopying the loss of the Fanconi anemia pathway. CCAR1 loss abrogated FANCA protein without substantial reduction in the level of its mRNA or that of other FA genes. We instead found that CCAR1 prevents inclusion of a poison exon in FANCA. Transcriptomic analysis revealed that the CCAR1 splicing modulatory activity is not limited to FANCA, and it instead regulates widespread changes in alternative splicing that would damage coding sequences in mouse and human cells. CCAR1 therefore has an unanticipated function as a splicing fidelity factor.
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Affiliation(s)
- Mehmet E Karasu
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology Zurich (ETH Zurich), Zurich 8093, Switzerland
| | - Leonard Jahnke
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology Zurich (ETH Zurich), Zurich 8093, Switzerland
| | - Brian J Joseph
- Department of Pathology and Cell Biology, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
| | - Yerkezhan Amerzhanova
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology Zurich (ETH Zurich), Zurich 8093, Switzerland
| | - Aleksei Mironov
- Computational and Systems Biology, Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - Xuan Shu
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology Zurich (ETH Zurich), Zurich 8093, Switzerland
| | - Markus S Schröder
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology Zurich (ETH Zurich), Zurich 8093, Switzerland
| | - Ana Gvozdenovic
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology Zurich (ETH Zurich), Zurich 8093, Switzerland
| | - Irene Sala
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology Zurich (ETH Zurich), Zurich 8093, Switzerland
| | - Mihaela Zavolan
- Computational and Systems Biology, Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - Stefanie Jonas
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology Zurich (ETH Zurich), Zurich 8093, Switzerland
| | - Jacob E Corn
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology Zurich (ETH Zurich), Zurich 8093, Switzerland.
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2
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He W, Demas DM, Shajahan-Haq AN, Baumann WT. Modeling breast cancer proliferation, drug synergies, and alternating therapies. iScience 2023; 26:106714. [PMID: 37234088 PMCID: PMC10206440 DOI: 10.1016/j.isci.2023.106714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 02/12/2023] [Accepted: 04/18/2023] [Indexed: 05/27/2023] Open
Abstract
Estrogen receptor positive (ER+) breast cancer is responsive to a number of targeted therapies used clinically. Unfortunately, the continuous application of targeted therapy often results in resistance, driving the consideration of combination and alternating therapies. Toward this end, we developed a mathematical model that can simulate various mono, combination, and alternating therapies for ER + breast cancer cells at different doses over long time scales. The model is used to look for optimal drug combinations and predicts a significant synergism between Cdk4/6 inhibitors in combination with the anti-estrogen fulvestrant, which may help explain the clinical success of adding Cdk4/6 inhibitors to anti-estrogen therapy. Furthermore, the model is used to optimize an alternating treatment protocol so it works as well as monotherapy while using less total drug dose.
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Affiliation(s)
- Wei He
- Program in Genetics, Bioinformatics, and Computational Biology, VT BIOTRANS, Virginia Tech, Blacksburg, VA 24061, USA
| | - Diane M. Demas
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA
| | - Ayesha N. Shajahan-Haq
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA
| | - William T. Baumann
- Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA 24061, USA
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3
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Zhang Y, Zhan K, Hu Z, Zhao G. SV40T/E6E7-Induced Proliferation Is Involved in the Activity of E2F3 in Bovine Mammary Epithelial Cells. Animals (Basel) 2022; 12:ani12141790. [PMID: 35883337 PMCID: PMC9312334 DOI: 10.3390/ani12141790] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 06/27/2022] [Accepted: 07/07/2022] [Indexed: 01/11/2023] Open
Abstract
Simple Summary A previous study demonstrated that SV40T does not require E2F1, E2F2, and E2F3 activators to induce proliferation in mouse embryo fibroblasts (MEFs). Our results showed that, at an early stage, primary bovine mammary epithelial cells (BMECs) lacking the E2F1 expression have the capacity to proliferate and show E2F2 and E2F3 slight protein levels. At a late stage, primary BMECs deficient for E2F3 completely abolish any proliferative ability and exhibit a severe cell senescence signal, although the E2F2 can be expressed at a late stage of primary BMECs. Compared with the late stage of primary BMECs, the BMECs immortalized by SV40T and E6E7 restored the protein level of E2F3. In conclusion, this study revealed a molecular mechanism where E2F3 controls the BMECs’ proliferation and senescence. Abstract The E2F family of transcription factor is divided into activators and repressors that control cell proliferation. Bovine mammary epithelial cells (BMECs) can be immortalized using human papillomavirus 16 E6E7 (HPV16 E6E7) and simian vacuolating virus 40 large T antigen (SV40T). In addition, SV40T does not require E2F1, E2F2, and E2F3 activators to induce proliferation in mouse embryo fibroblasts (MEFs). However, we report that E2F3 activator is required to induce the proliferation of BMECs. Our results showed that, at an early stage, primary BMECs lacking the E2F1 expression have the capacity to proliferate and show E2F2 and E2F3 slight protein levels. At a late stage, primary BMECs deficient for E2F3 completely abolish any proliferative ability and exhibit a severe cell senescence signal, although the E2F2 can be expressed at a late stage of primary BMECs. Compared with the late stage of primary BMECs, the BMECs immortalized by SV40T and E6E7 restored the protein level of E2F3 and enhanced the CDK4, CDK6, cyclin D3, and CDK2 protein level, leading to proliferating robustly. Surprisingly, it was found that p53, p21Cip1, and p27Kip1 were upregulated in SV40T and E6E7-immortalized BMECs, relatively to primary BMECs. Notably, Cdc2 was almost expressed in primary BMECs. However, Cdc2 was elevated in BMECs immortalized by SV40T and E6E7. In conclusion, this study revealed a molecular mechanism where E2F3 controls the BMECs’ proliferation and senescence.
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Affiliation(s)
- Yihui Zhang
- Experimental Farm of Yangzhou University, Yangzhou University, Yangzhou 225009, China; (Y.Z.); (K.Z.); (Z.H.)
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Kang Zhan
- Experimental Farm of Yangzhou University, Yangzhou University, Yangzhou 225009, China; (Y.Z.); (K.Z.); (Z.H.)
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Zixuan Hu
- Experimental Farm of Yangzhou University, Yangzhou University, Yangzhou 225009, China; (Y.Z.); (K.Z.); (Z.H.)
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Guoqi Zhao
- Experimental Farm of Yangzhou University, Yangzhou University, Yangzhou 225009, China; (Y.Z.); (K.Z.); (Z.H.)
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
- Correspondence: ; Tel.: +86-18852720422
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4
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Lee SH, Rodriguez LR, Majumdar R, De Marval PLM, Rodriguez-Puebla ML. CDK4 has the ability to regulate Aurora B and Cenpp expression in mouse keratinocytes. Oncol Lett 2021; 22:732. [PMID: 34429772 PMCID: PMC8371965 DOI: 10.3892/ol.2021.12993] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 07/16/2021] [Indexed: 11/29/2022] Open
Abstract
Cyclin-dependent kinase 4 (CDK4) is a critical molecule that regulates key aspects of cell proliferation through phosphorylation of the retinoblastoma (Rb) family of proteins. In the last few years, it has been suggested that CDK4 plays alternative roles in cell proliferation and tumorigenesis. The main aim of the present study was to define a novel CDK4 function as a transcriptional regulator of genes involved in chromosome segregation, contributing to the G2/M phase transition. Herein, chromatin-immunoprecipitation reverse transcription-quantitative PCR assays were performed to demonstrate that CDK4 could occupy the promoter region of genes associated with chromosomal segregation, such as Aurora-B (Aurkb) and Centromere Protein P (CENP-P). Moreover, gain- and loss-of-function experiments showed that CDK4 participated in the transcriptional regulation of Aurkb and CENP-P. The finding that Aurkb may have a crucial role in chromosome bi-orientation and the spindle assembly checkpoint, and that CENP-P could be required for proper kinetochore function suggests that dysregulation of CDK4 expression induces chromosomal instability and, in some cases, cancer development.
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Affiliation(s)
- Sung Hyun Lee
- Department of Molecular Biomedical Sciences, Center for Human Health and The Environment, North Carolina State University, Raleigh, NC 27607, USA
| | - Liliana R.L. Rodriguez
- Department of Clinical Analysis, General Acute Hospital, Parmenio Piñeiro, Buenos Aires 1406, Argentina
| | - Rima Majumdar
- Department of Molecular Biomedical Sciences, Center for Human Health and The Environment, North Carolina State University, Raleigh, NC 27607, USA
| | | | - Marcelo L. Rodriguez-Puebla
- Department of Molecular Biomedical Sciences, Center for Human Health and The Environment, North Carolina State University, Raleigh, NC 27607, USA
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5
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Todorovic Z, Milovanovic J, Arsenijevic D, Vukovic N, Vukic M, Arsenijevic A, Djurdjevic P, Milovanovic M, Arsenijevic N. Shikonin Derivatives from Onsoma visianii Decrease Expression of Phosphorylated STAT3 in Leukemia Cells and Exert Antitumor Activity. Nutrients 2021; 13:nu13041147. [PMID: 33807148 PMCID: PMC8065735 DOI: 10.3390/nu13041147] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 03/21/2021] [Accepted: 03/24/2021] [Indexed: 12/11/2022] Open
Abstract
Antitumor effects of shikonins on chronic lymphocytic leukemia (CLL) and B-cell prolymphocytic leukemia (B-PLL) are mostly unexplored. The antitumor activity of shikonins, isolated from Onosma visianii Clem (Boraginaceae), in BCL1, mouse CLL cells and JVM-13, human B-PLL cells was explored in this study. The cytotoxicity of shikonin derivatives was measured by an MTT test. Cell death, proliferation, cell cycle, and expression of molecules that control these processes were analyzed by flow cytometry. Expression of STAT3-regulated genes was analyzed by real-time q-RT-PCR (Quantitative Real-Time Polymerase Chain Reaction). The antitumor effects of shikonin derivatives in vivo were analyzed, using flow cytometry, by detection of leukemia cells in the peripheral blood and spleens of mice intravenously injected with BCL1 cells. The two most potent derivatives, isobutyrylshikonin (IBS) and α-methylbutyrylshikonin (MBS), induced cell cycle disturbances and apoptosis, inhibited proliferation, and decreased expression of phospho-STAT3 and downstream-regulated molecules in BCL1 and JVM-13 cells. IBS and MBS decreased the percentage of leukemia cells in vivo. The link between the decrease in phosphorylated STAT3 by MBS and IBS and BCL1 cell death was confirmed by detection of enhanced cell death after addition of AG490, an inhibitor of Jak2 kinase. It seems that IBS and MBS, by decreasing STAT3 phosphorylation, trigger apoptosis, inhibit cell proliferation, and attenuate leukemia cell stemness.
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Affiliation(s)
- Zeljko Todorovic
- Department of Internal Medicine, Faculty of Medical Sciences, University of Kragujevac, 34000 Kragujevac, Serbia; (Z.T.); (P.D.)
| | - Jelena Milovanovic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, 34000 Kragujevac, Serbia; (J.M.); (D.A.); (A.A.); (N.A.)
- Department of Histology and Embriology, Faculty of Medical Sciences, University of Kragujevac, 34000 Kragujevac, Serbia
| | - Dragana Arsenijevic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, 34000 Kragujevac, Serbia; (J.M.); (D.A.); (A.A.); (N.A.)
- Department of Pharmacy, Faculty of Medical Sciences, University of Kragujevac, 34000 Kragujevac, Serbia
| | - Nenad Vukovic
- Department of Chemistry, Faculty of Science, University of Kragujevac, 34000 Kragujevac, Serbia; (N.V.); (M.V.)
| | - Milena Vukic
- Department of Chemistry, Faculty of Science, University of Kragujevac, 34000 Kragujevac, Serbia; (N.V.); (M.V.)
| | - Aleksandar Arsenijevic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, 34000 Kragujevac, Serbia; (J.M.); (D.A.); (A.A.); (N.A.)
| | - Predrag Djurdjevic
- Department of Internal Medicine, Faculty of Medical Sciences, University of Kragujevac, 34000 Kragujevac, Serbia; (Z.T.); (P.D.)
| | - Marija Milovanovic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, 34000 Kragujevac, Serbia; (J.M.); (D.A.); (A.A.); (N.A.)
- Correspondence: ; Tel.: +381-34306800
| | - Nebojsa Arsenijevic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, 34000 Kragujevac, Serbia; (J.M.); (D.A.); (A.A.); (N.A.)
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6
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Patel S, Wilkinson CJ, Sviderskaya EV. Loss of Both CDKN2A and CDKN2B Allows for Centrosome Overduplication in Melanoma. J Invest Dermatol 2020; 140:1837-1846.e1. [PMID: 32067956 PMCID: PMC7435684 DOI: 10.1016/j.jid.2020.01.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 12/23/2019] [Accepted: 01/13/2020] [Indexed: 02/06/2023]
Abstract
Centrosomes duplicate only once in coordination with the DNA replication cycle and have an important role in segregating genetic material. In contrast, most cancer cells have centrosome aberrations, including supernumerary centrosomes, and this correlates with aneuploidy and genetic instability. The tumor suppressors p16 (CDKN2A) and p15 (CDKN2B) (encoded by the familial melanoma CDKN2 locus) inhibit CDK4/6 activity and have important roles in cellular senescence. p16 is also associated with suppressing centrosomal aberrations in breast cancer; however, the role of p15 in centrosome amplification is unknown. Here, we investigated the relationship between p15 and p16 expression, centrosome number abnormalities, and melanoma progression in cell lines derived from various stages of melanoma progression. We found that normal human melanocyte lines did not exhibit centrosome number abnormalities, whereas those from later stages of melanoma did. Additionally, under conditions of S-phase block, p15 and p16 status determined whether centrosome overduplication would occur. Indeed, removal of p15 from p16-negative cell lines derived from various stages of melanoma progression changed cells that previously would not overduplicate their centrosomes into cells that did. Although this study used cell lines in vitro, it suggests that, during clinical melanoma progression, sequential loss of p15 and p16 provides conditions for centrosome duplication to become deregulated with consequences for genome instability.
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Affiliation(s)
- Shyamal Patel
- Cell Biology Research Centre, Molecular and Clinical Sciences Research Institute, St. George's, University of London, Cranmer Terrace, London, United Kingdom
| | - Christopher J Wilkinson
- Centre for Biomedical Sciences, Department of Biological Sciences, School of Life Sciences and the Environment, Royal Holloway University of London, Egham, United Kingdom
| | - Elena V Sviderskaya
- Cell Biology Research Centre, Molecular and Clinical Sciences Research Institute, St. George's, University of London, Cranmer Terrace, London, United Kingdom.
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7
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Russo LC, Farias JO, Forti FL. DUSP3 maintains genomic stability and cell proliferation by modulating NER pathway and cell cycle regulatory proteins. Cell Cycle 2020; 19:1545-1561. [PMID: 32380926 DOI: 10.1080/15384101.2020.1762043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The DUSP3 phosphatase regulates cell cycle, proliferation, apoptosis and senescence of different cell types, lately shown as a mediator of DNA repair processes. This work evaluated the impact of DUSP3 loss of function (lof) on DNA repair-proficient fibroblasts (MRC-5), NER-deficient cell lines (XPA and XPC) and translesion DNA synthesis (TLS)-deficient cells (XPV), after UV-radiation stress. The levels of DNA strand breaks, CPDs and 6-4-PPs have accumulated over time in all cells under DUSP3 lof, with a significant increase in NER-deficient lines. The inefficient repair of these lesions increased sub-G1 population of XPA and XPC cells 24 hours after UV treatment, notably marked by DUSP3 lof, which is associated with a reduced cell population in G1, S and G2/M phases. It was also detected an increase in S and G2/M populations of XPV and MRC-5 cells after UV-radiation exposure, which was slightly attenuated by DUSP3 lof due to a discrete increase in sub-G1 cells. The cell cycle progression was accompanied by changes in the levels of the main Cyclins (A1, B1, D1 or E1), CDKs (1, 2, 4 or 6), and the p21 Cip1 inhibitor, in a DUSP3-dependent manner. DUSP3 lof affected the proliferation of MRC-5 and XPA cells, with marked worsening of the XP phenotype after UV radiation. This work highlights the roles of DUSP3 in DNA repair fitness and in the fine control of regulatory proteins of cell cycle, essential mechanisms to maintenance of genomic stability.
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Affiliation(s)
- Lilian Cristina Russo
- Laboratory of Signaling in Biomolecular Systems, Department of Biochemistry, Institute of Chemistry, University of Sao Paulo , São Paulo-SP, Brazil
| | - Jessica Oliveira Farias
- Laboratory of Signaling in Biomolecular Systems, Department of Biochemistry, Institute of Chemistry, University of Sao Paulo , São Paulo-SP, Brazil
| | - Fabio Luis Forti
- Laboratory of Signaling in Biomolecular Systems, Department of Biochemistry, Institute of Chemistry, University of Sao Paulo , São Paulo-SP, Brazil
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8
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Mitchell DC, Menon A, Garner AL. Cyclin-dependent kinase 4 inhibits the translational repressor 4E-BP1 to promote cap-dependent translation during mitosis-G1 transition. FEBS Lett 2019; 594:1307-1318. [PMID: 31853978 DOI: 10.1002/1873-3468.13721] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 12/02/2019] [Accepted: 12/04/2019] [Indexed: 01/18/2023]
Abstract
Phosphorylation of translational repressor eukaryotic translation initiation factor 4E (eIF4E)-binding protein 1 (4E-BP1) controls the initiation of cap-dependent translation, a type of protein synthesis that is frequently upregulated in human diseases such as cancer. Because of its critical cellular function, it is not surprising that multiple kinases can post-translationally modify 4E-BP1 to drive aberrant cap-dependent translation. We recently reported a site-selective chemoproteomic method for uncovering kinase-substrate interactions, and using this approach, we discovered the cyclin-dependent kinase (CDK)4 as a new 4E-BP1 kinase. Herein, we describe our extension of this work and reveal the role of CDK4 in modulating 4E-BP1 activity in the transition from mitosis to G1, thereby demonstrating a novel role for this kinase in cell cycle regulation.
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Affiliation(s)
- Dylan C Mitchell
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI, USA
| | - Arya Menon
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI, USA
| | - Amanda L Garner
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI, USA.,Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI, USA
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9
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Chao HX, Fakhreddin RI, Shimerov HK, Kedziora KM, Kumar RJ, Perez J, Limas JC, Grant GD, Cook JG, Gupta GP, Purvis JE. Evidence that the human cell cycle is a series of uncoupled, memoryless phases. Mol Syst Biol 2019; 15:e8604. [PMID: 30886052 PMCID: PMC6423720 DOI: 10.15252/msb.20188604] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 02/07/2019] [Accepted: 02/08/2019] [Indexed: 01/03/2023] Open
Abstract
The cell cycle is canonically described as a series of four consecutive phases: G1, S, G2, and M. In single cells, the duration of each phase varies, but the quantitative laws that govern phase durations are not well understood. Using time-lapse microscopy, we found that each phase duration follows an Erlang distribution and is statistically independent from other phases. We challenged this observation by perturbing phase durations through oncogene activation, inhibition of DNA synthesis, reduced temperature, and DNA damage. Despite large changes in durations in cell populations, phase durations remained uncoupled in individual cells. These results suggested that the independence of phase durations may arise from a large number of molecular factors that each exerts a minor influence on the rate of cell cycle progression. We tested this model by experimentally forcing phase coupling through inhibition of cyclin-dependent kinase 2 (CDK2) or overexpression of cyclin D. Our work provides an explanation for the historical observation that phase durations are both inherited and independent and suggests how cell cycle progression may be altered in disease states.
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Affiliation(s)
- Hui Xiao Chao
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Curriculum for Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Randy I Fakhreddin
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Hristo K Shimerov
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Katarzyna M Kedziora
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Rashmi J Kumar
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Joanna Perez
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Juanita C Limas
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Gavin D Grant
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Jeanette Gowen Cook
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Gaorav P Gupta
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Radiation Oncology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Jeremy E Purvis
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Curriculum for Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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10
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Li X, Lu J, Kan Q, Li X, Fan Q, Li Y, Huang R, Slipicevic A, Dong HP, Eide L, Wang J, Zhang H, Berge V, Goscinski MA, Kvalheim G, Nesland JM, Suo Z. Metabolic reprogramming is associated with flavopiridol resistance in prostate cancer DU145 cells. Sci Rep 2017; 7:5081. [PMID: 28698547 PMCID: PMC5506068 DOI: 10.1038/s41598-017-05086-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 05/24/2017] [Indexed: 01/19/2023] Open
Abstract
Flavopiridol (FP) is a pan-cyclin dependent kinase inhibitor, which shows strong efficacy in inducing cancer cell apoptosis. Although FP is potent against most cancer cells in vitro, unfortunately it proved less efficacious in clinical trials in various aggressive cancers. To date, the molecular mechanisms of the FP resistance are mostly unknown. Here, we report that a small fraction human prostate cancer DU145 cells can survive long-term FP treatment and emerge as FP-resistant cells (DU145FP). These DU145FP cells show accumulated mitochondrial lesions with stronger glycolytic features, and they proliferate in slow-cycling and behave highly migratory with strong anti-apoptotic potential. In addition, the cells are less sensitive to cisplatin and docetaxel-induced apoptotic pressure, and over-express multiple stem cell associated biomarkers. Our studies collectively uncover for the first time that FP-resistant prostate cancer cells show metabolic remodeling, and the metabolic plasticity might be required for the FP resistance-associated cancer cell stemness up-regulation.
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Affiliation(s)
- Xiaoran Li
- Department of Pathology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, 0379, Norway
- Department of Pathology, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, 0318, Norway
| | - Jie Lu
- Department of Epidemiology and Biostatistics, College of Public Health, Zhengzhou University, Zhengzhou, Henan, 450001, China
| | - Quancheng Kan
- Department of Clinical Pharmacology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, 450001, China
| | - Xiaoli Li
- Department of Oncology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, 450052, China
| | - Qiong Fan
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Oslo, 0316, Norway
| | - Yaqing Li
- Department of Oncology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, 450052, China
| | - Ruixia Huang
- Department of Radiation Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, 0379, Norway
| | - Ana Slipicevic
- Department of Pathology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, 0379, Norway
| | - Hiep Phuc Dong
- Department of Pathology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, 0379, Norway
| | - Lars Eide
- Department of Medical Biochemistry, University of Oslo and Oslo University Hospital, Oslo, 0372, Norway
| | - Junbai Wang
- Department of Pathology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, 0379, Norway
| | - Hongquan Zhang
- Laboratory of Molecular Cell Biology and Tumor Biology, Department of Anatomy, Histology and Embryology, Peking University Health Science Center, Beijing, 100191, China
| | - Viktor Berge
- Department of Urology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, 0379, Norway
| | - Mariusz Adam Goscinski
- Departments of Surgery, The Norwegian Radium Hospital, Oslo University Hospital, Institute for Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, 0379, Norway
| | - Gunnar Kvalheim
- Department of Cell Therapy, Cancer Institute, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, 0379, Norway
| | - Jahn M Nesland
- Department of Pathology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, 0379, Norway
- Department of Pathology, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, 0318, Norway
| | - Zhenhe Suo
- Department of Pathology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, 0379, Norway.
- Department of Pathology, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, 0318, Norway.
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11
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Wei J, Huang Q, Bai F, Lin J, Nie J, Lu S, Lu C, Huang R, Lu Z, Lin X. Didymin induces apoptosis through mitochondrial dysfunction and up-regulation of RKIP in human hepatoma cells. Chem Biol Interact 2017; 261:118-126. [DOI: 10.1016/j.cbi.2016.11.026] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 11/06/2016] [Accepted: 11/24/2016] [Indexed: 12/27/2022]
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12
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Rakshit N, Yang S, Zhou W, Xu Y, Deng C, Yang J, Yu H, Wei W. Adenovirus-mediated co-expression of ING4 and PTEN cooperatively enhances their antitumor activity in human hepatocellular carcinoma cells. Acta Biochim Biophys Sin (Shanghai) 2016; 48:704-13. [PMID: 27421660 DOI: 10.1093/abbs/gmw062] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 05/24/2016] [Indexed: 11/13/2022] Open
Abstract
Both inhibitor of growth 4 (ING4) and phosphatase and tensin homolog deleted on chromosome 10 (PTEN) are well known as tumor suppressors that are closely related to tumor occurrence and progression. It was reported that ING4 and PTEN showed synergistic antitumor activities in nasopharyngeal carcinoma cells. The two tumor suppressors demonstrated synergistic effect on growth inhibition and apoptosis activation. In this study, we investigated their therapeutic potential in hepatocellular carcinoma (HCC) cells. Recombinant adenoviruses co-expressing ING4 and PTEN (Ad-ING4-PTEN) were constructed, and the antitumor effect on SMMC-7721 and HepG2 HCC cells was evaluated. Ad-ING4-PTEN cooperatively inhibited cell growth, stimulated apoptosis, and suppressed invasion in both HCC cells, and regulated cell cycle in SMMC-7721. Further studies showed that the combination of ING4 and PTEN by Ad-ING4-PTEN cooperatively enhanced the alteration of the expression of cell cycle-related proteins (p53, p21, and cyclin D1) and apoptotic factors (Bad, Bcl-2, Bcl-XL, and Bax), which are involved in the regulation of cell cycle and the activation of apoptotic pathways, leading to the synergistic antitumor effect. These results indicate that the combination of ING4 and PTEN may provide an effective therapeutic strategy for HCC.
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Affiliation(s)
- Nargis Rakshit
- Department of Cell Biology, School of Medicine, Soochow University, Suzhou 215123, China
| | - Sijun Yang
- School of Life Science, Shangrao Normal University, Shangrao 334001, China
| | - Wei Zhou
- Department of Cell Biology, School of Medicine, Soochow University, Suzhou 215123, China
| | - Yi Xu
- Department of Cell Biology, School of Medicine, Soochow University, Suzhou 215123, China
| | - Chenghui Deng
- Department of Cell Biology, School of Medicine, Soochow University, Suzhou 215123, China
| | - Jiecheng Yang
- Department of Cell Biology, School of Medicine, Soochow University, Suzhou 215123, China
| | - Huijun Yu
- Department of Cell Biology, School of Medicine, Soochow University, Suzhou 215123, China
| | - Wenxiang Wei
- Department of Cell Biology, School of Medicine, Soochow University, Suzhou 215123, China
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13
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Brookes S, Gagrica S, Sanij E, Rowe J, Gregory FJ, Hara E, Peters G. Evidence for a CDK4-dependent checkpoint in a conditional model of cellular senescence. Cell Cycle 2016; 14:1164-73. [PMID: 25695870 PMCID: PMC4613988 DOI: 10.1080/15384101.2015.1010866] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Cellular senescence, the stable cell cycle arrest elicited by various forms of stress, is an important facet of tumor suppression. Although much is known about the key players in the implementation of senescence, including the pRb and p53 axes and the cyclin dependent kinase inhibitors p16INK4a and p21CIP1, many details remain unresolved. In studying conditional senescence in human fibroblasts that express a temperature sensitive SV40 large T-antigen (T-Ag), we uncovered an unexpected role for CDK4. At the permissive temperature, where pRb and p53 are functionally compromised by T-Ag, cyclin D-CDK4 complexes are disrupted by the high p16INK4a levels and reduced expression of p21CIP1. In cells arrested at the non-permissive temperature, p21CIP1 promotes reassembly of cyclin D-CDK4 yet pRb is in a hypo-phosphorylated state, consistent with cell cycle arrest. In exploring whether the reassembled cyclin D-CDK4-p21 complexes are functional, we found that shRNA-mediated knockdown or chemical inhibition of CDK4 prevented the increase in cell size associated with the senescent phenotype by allowing the cells to arrest in G1 rather than G2/M. The data point to a role for CDK4 kinase activity in a G2 checkpoint that contributes to senescence.
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Key Words
- BrdU, bromodeoxyuridine
- CDK, cyclin dependent kinase
- CDK4
- FACS, fluorescence actvated cell sorting
- HFs, human fibroblasts
- PI, propidium iodide
- SA-βgal, senescence-associated β-galactosidase activity
- SV40 T-antigen
- SV40, simian virus 40
- TERT, telomerase reverse transcriptase
- human fibroblasts
- p16INK4a
- p21CIP1
- p53
- pRb, retinoblastoma protein
- retinoblastoma protein
- senescence
- shRNA, short-hairpin RNA
- ts, temperature sensitive
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Affiliation(s)
- Sharon Brookes
- a Cancer Research-UK London Research Institute ; London , UK
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14
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Megiorni F, McDowell HP, Camero S, Mannarino O, Ceccarelli S, Paiano M, Losty PD, Pizer B, Shukla R, Pizzuti A, Clerico A, Dominici C. Crizotinib-induced antitumour activity in human alveolar rhabdomyosarcoma cells is not solely dependent on ALK and MET inhibition. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2015; 34:112. [PMID: 26445453 PMCID: PMC4596370 DOI: 10.1186/s13046-015-0228-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 09/29/2015] [Indexed: 12/30/2022]
Abstract
Background Rhabdomyosarcoma (RMS) is the most commonly diagnosed malignant soft tissue tumour in children and adolescents. Aberrant expression of Anaplastic Lymphoma Kinase (ALK) and MET gene has been implicated in the malignant progression of RMS, especially in the alveolar subtype. This observation suggests that crizotinib (PF-02341066), a kinase inhibitor against ALK and MET, may have a therapeutic role in RMS, although its antitumour activity in this malignancy has not yet been studied. Methods RH4 and RH30 alveolar RMS (ARMS) cell lines were treated with crizotinib and then assessed by using proliferation, viability, migration and colony formation assays. Multiple approaches, including flow cytometry, immunofluorescence, western blotting and siRNA-based knock-down, were used in order to investigate possible molecular mechanisms linked to crizotinib activity. Results In vitro treatment with crizotinib inhibited ALK and MET proteins, as well as Insulin-like Growth Factor 1 Receptor (IGF1R), with a concomitant robust dephosphorylation of AKT and ERK, two downstream kinases involved in RMS cell proliferation and survival. Exposure to crizotinib impaired cell growth, and accumulation at G2/M phase was attributed to an altered expression and activation of checkpoint regulators, such as Cyclin B1 and Cdc2. Crizotinib was able to induce apoptosis and autophagy in a dose-dependent manner, as shown by caspase-3 activation/PARP proteolytic cleavage down-regulation and by LC3 activation/p62 down-regulation, respectively. The accumulation of reactive oxygen species (ROS) seemed to contribute to crizotinib effects in RH4 and RH30 cells. Moreover, crizotinib-treated RH4 and RH30 cells exhibited a decreased migratory/invasive capacity and clonogenic potential. Conclusions These results provide a further insight into the molecular mechanisms affected by crizotinib in ARMS cells inferring that it could be a useful therapeutic tool in ARMS cancer treatment. Electronic supplementary material The online version of this article (doi:10.1186/s13046-015-0228-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Francesca Megiorni
- Department of Paediatrics and Infantile Neuropsychiatry, Sapienza University, Viale Regina Elena 324, 00161, Rome, Italy.
| | - Heather P McDowell
- Department of Paediatrics and Infantile Neuropsychiatry, Sapienza University, Viale Regina Elena 324, 00161, Rome, Italy. .,Department of Oncology, Alder Hey Children's NHS Foundation Trust, Eaton Road, L12 2AP, Liverpool, UK.
| | - Simona Camero
- Department of Paediatrics and Infantile Neuropsychiatry, Sapienza University, Viale Regina Elena 324, 00161, Rome, Italy.
| | - Olga Mannarino
- Department of Paediatrics and Infantile Neuropsychiatry, Sapienza University, Viale Regina Elena 324, 00161, Rome, Italy.
| | - Simona Ceccarelli
- Department of Experimental Medicine, Sapienza University of Rome, Viale Regina Elena 324, 00161, Rome, Italy.
| | - Milena Paiano
- Department of Paediatrics and Infantile Neuropsychiatry, Sapienza University, Viale Regina Elena 324, 00161, Rome, Italy.
| | - Paul D Losty
- Department of Paediatric Surgery, Alder Hey Children's NHS Foundation Trust; Academic Paediatric Surgery Unit, University of Liverpool, Eaton Road, L12 2AP, Liverpool, UK.
| | - Barry Pizer
- Department of Oncology, Alder Hey Children's NHS Foundation Trust, Eaton Road, L12 2AP, Liverpool, UK.
| | - Rajeev Shukla
- Department of Perinatal and Paediatric Pathology, Alder Hey Children's NHS Foundation Trust, Eaton Road, L12 2AP, Liverpool, UK.
| | - Antonio Pizzuti
- Department of Experimental Medicine, Sapienza University of Rome, Viale Regina Elena 324, 00161, Rome, Italy.
| | - Anna Clerico
- Department of Paediatrics and Infantile Neuropsychiatry, Sapienza University, Viale Regina Elena 324, 00161, Rome, Italy.
| | - Carlo Dominici
- Department of Paediatrics and Infantile Neuropsychiatry, Sapienza University, Viale Regina Elena 324, 00161, Rome, Italy.
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15
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Li Y, Zhang H, Zhu X, Feng D, Zhang D, Zhuo B, Zheng J. Oncolytic adenovirus-mediated short hairpin RNA targeting MYCN gene induces apoptosis by upregulating RKIP in neuroblastoma. Tumour Biol 2015; 36:6037-43. [PMID: 25736927 DOI: 10.1007/s13277-015-3280-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 02/18/2015] [Indexed: 10/23/2022] Open
Abstract
The amplification of MYCN is a typical characteristic of aggressive neuroblastomas, whereas acquired mutations of p53 lead to refractory and relapsed cases. We had previously examined the applicability of the replication-competent oncolytic adenovirus, ZD55-shMYCN, to deliver a short hairpin RNA targeting MYCN gene for p53-null and MYCN-amplified neuroblastoma cell line LA1-55N. Our data have shown that ZD55-shMYCN has an additive tumor growth inhibitory response through shRNA-mediated MYCN knockdown and ZD55-mediated cancer cell lysis. In this regard, ZD55-shMYCN can downregulate MYCN and perform anticancer effects, thereby acquiring significance in the administration of MYCN-amplified and p53-null neuroblastomas. Hence, we further investigated the anticancer properties of ZD55-shMYCN in neuroblastomas. Our data showed that ZD55-shMYCN induced G2/M arrest via decreasing the levels of cyclin D1 and cyclin B1 irrespective of p53 status. ZD55-shMYCN effectively induced apoptosis in neuroblastomas through activation of caspase-3 and enhancing PARP cleavage. Furthermore, ZD55-shMYCN could downregulate phosphoinositide 3-kinase and pAkt and upregulate RKIP levels. Similarly, pro-apoptosis was revealed by the histopathologic examination of paraffin-embedded section of resected tumors of mice xenograft. In vitro and in vivo studies, we elucidate the apoptosis properties and mechanisms of action of ZD55-shMYCN, which provide a promising approach for further clinical development.
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Affiliation(s)
- Yuan Li
- Department of Pediatric Surgery, Xuzhou Children's Hospital, 18 Suti North Road, Xuzhou, 221006, Jiangsu, China,
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16
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De Luca G, Ferretti R, Bruschi M, Mezzaroma E, Caruso M. Cyclin D3 critically regulates the balance between self-renewal and differentiation in skeletal muscle stem cells. Stem Cells 2014; 31:2478-91. [PMID: 23897741 PMCID: PMC3963451 DOI: 10.1002/stem.1487] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Revised: 05/26/2013] [Accepted: 06/21/2013] [Indexed: 12/28/2022]
Abstract
Satellite cells are mitotically quiescent myogenic stem cells resident beneath the basal lamina surrounding adult muscle myofibers. In response to injury, multiple extrinsic signals drive the entry of satellite cells into the cell cycle and then to proliferation, differentiation, and self-renewal of their downstream progeny. Because satellite cells must endure for a lifetime, their cell cycle activity must be carefully controlled to coordinate proliferative expansion and self-renewal with the onset of the differentiation program. In this study, we find that cyclin D3, a member of the family of mitogen-activated D-type cyclins, is critically required for proper developmental progression of myogenic progenitors. Using a cyclin D3-knockout mouse we determined that cyclin D3 deficiency leads to reduced myofiber size and impaired establishment of the satellite cell population within the adult muscle. Cyclin D3-null myogenic progenitors, studied ex vivo on isolated myofibers and in vitro, displayed impaired cell cycle progression, increased differentiation potential, and reduced self-renewal capability. Similarly, silencing of cyclin D3 in C2 myoblasts caused anticipated exit from the cell cycle and precocious onset of terminal differentiation. After induced muscle damage, cyclin D3-null myogenic progenitors exhibited proliferation deficits, a precocious ability to form newly generated myofibers and a reduced capability to repopulate the satellite cell niche at later stages of the regeneration process. These results indicate that cyclin D3 plays a cell-autonomous and nonredundant function in regulating the dynamic balance between proliferation, differentiation, and self-renewal that normally establishes an appropriate pool size of adult satellite cells.
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Affiliation(s)
- Giulia De Luca
- National Research Council, Institute of Cell Biology and Neurobiology, Fondazione Santa Lucia, Roma, Italy
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17
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Lou X, Zhang J, Liu S, Xu N, Liao DJ. The other side of the coin: the tumor-suppressive aspect of oncogenes and the oncogenic aspect of tumor-suppressive genes, such as those along the CCND-CDK4/6-RB axis. Cell Cycle 2014; 13:1677-93. [PMID: 24799665 DOI: 10.4161/cc.29082] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Although cancer-regulatory genes are dichotomized to oncogenes and tumor-suppressor gene s, in reality they can be oncogenic in one situation but tumor-suppressive in another. This dual-function nature, which sometimes hampers our understanding of tumor biology, has several manifestations: (1) Most canonically defined genes have multiple mRNAs, regulatory RNAs, protein isoforms, and posttranslational modifications; (2) Genes may interact at different levels, such as by forming chimeric RNAs or by forming different protein complexes; (3) Increased levels of tumor-suppressive genes in normal cells drive proliferation of cancer progenitor cells in the same organ or tissue by imposing compensatory proliferation pressure, which presents the dual-function nature as a cell-cell interaction. All these manifestations of dual functions can find examples in the genes along the CCND-CDK4/6-RB axis. The dual-function nature also underlies the heterogeneity of cancer cells. Gene-targeting chemotherapies, including that targets CDK4, are effective to some cancer cells but in the meantime may promote growth or progression of some others in the same patient. Redefining "gene" by considering each mRNA, regulatory RNA, protein isoform, and posttranslational modification from the same genomic locus as a "gene" may help in better understanding tumor biology and better selecting targets for different sub-populations of cancer cells in individual patients for personalized therapy.
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Affiliation(s)
- Xiaomin Lou
- CAS Key Laboratory of Genome Sciences and Information; Beijing Institute of Genomics; Chinese Academy of Sciences; Beijing, PR China
| | - Ju Zhang
- CAS Key Laboratory of Genome Sciences and Information; Beijing Institute of Genomics; Chinese Academy of Sciences; Beijing, PR China
| | - Siqi Liu
- CAS Key Laboratory of Genome Sciences and Information; Beijing Institute of Genomics; Chinese Academy of Sciences; Beijing, PR China
| | - Ningzhi Xu
- Laboratory of Cell and Molecular Biology; Cancer Institute; Chinese Academy of Medical Science; Beijing, PR China
| | - D Joshua Liao
- Hormel Institute; University of Minnesota; Austin, MN USA
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18
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Jadhav KS, Dungan CM, Williamson DL. Metformin limits ceramide-induced senescence in C2C12 myoblasts. Mech Ageing Dev 2013; 134:548-59. [PMID: 24269881 DOI: 10.1016/j.mad.2013.11.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 10/26/2013] [Accepted: 11/11/2013] [Indexed: 12/14/2022]
Abstract
UNLABELLED High lipid and ceramide concentrations are hallmarks of obese and/or insulin resistant skeletal muscle, yet little is known about its role on cell cycle and senescence. The purpose of this study was to examine the role of ceramide on muscle senescence, and whether metformin limited this response. METHODS Low passage, proliferating C2C12 myoblasts were treated with a control, 50μM C2-ceramide (8h), and/or 2mM metformin, then examined for insulin sensitivity, cell senescence, cell proliferation, cell cycle, protein expression of cell cycle regulators. RESULTS Ceramide treatment caused a dephosphorylation (p<0.05) of Akt and 4E-BP1, regardless of the presence of insulin. The ceramide treated myoblasts displayed higher β-galactosidase staining (p<0.05), reduced BrDu incorporation and total number of cells (p<0.05), and an increased proportion of cells in G2-phase (p<0.05) versus control cultures. Ceramide treatment also upregulated (p<0.05) p53 and p21 protein expression, that was reversed by either pifithrin-α or shRNA for p53. Metformin limited (p<0.05) ceramide's effects on insulin signaling, senescence, and cell cycle regulation. CONCLUSIONS High ceramide concentrations reduced myoblast proliferation that was associated with aberrant cell cycle regulation and a senescent phenotype, which could provide an understanding of skeletal muscle cell adaptation during conditions of high intramuscular lipid deposition and/or obesity.
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Affiliation(s)
- Kavita S Jadhav
- Department of Exercise and Nutrition Sciences, University at Buffalo SUNY, Buffalo, NY 14214, USA
| | - Cory M Dungan
- Department of Exercise and Nutrition Sciences, University at Buffalo SUNY, Buffalo, NY 14214, USA
| | - David L Williamson
- Department of Exercise and Nutrition Sciences, University at Buffalo SUNY, Buffalo, NY 14214, USA.
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19
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Sun Y, Lou X, Yang M, Yuan C, Ma L, Xie BK, Wu JM, Yang W, Shen SX, Xu N, Liao DJ. Cyclin-dependent kinase 4 may be expressed as multiple proteins and have functions that are independent of binding to CCND and RB and occur at the S and G 2/M phases of the cell cycle. Cell Cycle 2013; 12:3512-25. [PMID: 24091631 DOI: 10.4161/cc.26510] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Cyclin-dependent kinase 4 (CDK4) is known to be a 33 kD protein that drives G 1 phase progression of the cell cycle by binding to a CCND protein to phosphorylate RB proteins. Using different CDK4 antibodies in western blot, we detected 2 groups of proteins around 40 and 33 kD, respectively, in human and mouse cells; each group often appeared as a duplet or triplet of bands. Some CDK4 shRNAs could decrease the 33 kD wild-type (wt) CDK4 but increase some 40 kD proteins, whereas some other shRNAs had the opposite effects. Liquid chromatography-mass spectrometry/mass spectrometry analysis confirmed the existence of CDK4 isoforms smaller than 33 kD but failed to identify CDK4 at 40 kD. We cloned one CDK4 mRNA variant that lacks exon 2 and encodes a 26 kD protein without the first 74 amino acids of the wt CDK4, thus lacking the ATP binding sequence and the PISTVRE domain required for binding to CCND. Co-IP assay confirmed that this ΔE2 protein lost CCND1- and RB1-binding ability. Moreover, we found, surprisingly, that the wt CDK4 and the ΔE2 could inhibit G 1-S progression, accelerate S-G 2/M progression, and enhance or delay apoptosis in a cell line-specific manner in a situation where the cells were treated with a CDK4 inhibitor or the cells were serum-starved and then replenished. Hence, CDK4 seems to be expressed as multiple proteins that react differently to different CDK4 antibodies, respond differently to different shRNAs, and, in some situations, have previously unrecognized functions at the S-G 2/M phases of the cell cycle via mechanisms independent of binding to CCND and RB.
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Affiliation(s)
- Yuan Sun
- Hormel Institute; The University of Minnesota; Austin, MN USA
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20
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Pavey S, Spoerri L, Haass NK, Gabrielli B. DNA repair and cell cycle checkpoint defects as drivers and therapeutic targets in melanoma. Pigment Cell Melanoma Res 2013; 26:805-16. [PMID: 23837768 DOI: 10.1111/pcmr.12136] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 07/05/2013] [Indexed: 01/07/2023]
Abstract
The ultraviolet radiation (UVR) component of sunlight is the major environmental risk factor for melanoma, producing DNA lesions that can be mutagenic if not repaired. The high level of mutations in melanomas that have the signature of UVR-induced damage indicates that the normal mechanisms that detect and repair this damage must be defective in this system. With the exception of melanoma-prone heritable syndromes which have mutations of repair genes, there is little evidence for somatic mutation of known repair genes. Cell cycle checkpoint controls are tightly associated with repair mechanisms, arresting cells to allow for repair before continuing through the cell cycle. Checkpoint signaling components also regulate the repair mechanisms. Defects in checkpoint mechanisms have been identified in melanomas and are likely to be responsible for increased mutation load in melanoma. Loss of the checkpoint responses may also provide an opportunity to target melanomas using a synthetic lethal approach to identify and inhibit mechanisms that compensate for the defective checkpoints.
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Affiliation(s)
- Sandra Pavey
- The University of Queensland Diamantina Institute, Translational Research Institute, Brisbane, Qld, Australia
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21
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He X, Dong Y, Wu CW, Zhao Z, Ng SSM, Chan FKL, Sung JJY, Yu J. MicroRNA-218 inhibits cell cycle progression and promotes apoptosis in colon cancer by downregulating BMI1 polycomb ring finger oncogene. Mol Med 2013; 18:1491-8. [PMID: 23255074 DOI: 10.2119/molmed.2012.00304] [Citation(s) in RCA: 126] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2012] [Accepted: 12/11/2012] [Indexed: 01/12/2023] Open
Abstract
Deregulated miRNAs participate in colorectal carcinogenesis. In this study, miR-218 was found to be downregulated in human colorectal cancer (CRC) by miRNA profile assay. miR-218 was silenced or downregulated in all five colon cancer cells (Caco2, HT29, SW620, HCT116 and LoVo) relative to normal colon tissues. miR-218 expression was significantly lower in 46 CRC tumor tissues compared with their adjacent normal tissues (P < 0.001). Potential target genes of miR-218 were predicted and BMI1 polycomb ring finger oncogene (BMI-1), a polycomb ring finger oncogene, was identified as one of the potential targets. Upregulation of BMI-1 was detected in CRC tumors compared with adjacent normal tissues (P < 0.001) and in all five colon cancer cell lines. Transfection of miR-218 in colon cancer cell lines (HCT116, HT29) significantly reduced luciferase activity of the wild-type construct of BMI-1 3' untranslated region (3'UTR) (P < 0.001), whereas this effect was not seen in the construct with mutant BMI-1 3'UTR, indicating a direct and specific interaction of miR-218 with BMI-1. Ectopic expression of miR-218 in HCT116 and HT29 cells suppressed BMI-1 mRNA and protein expression. In addition, miR-218 suppressed protein expression of BMI-1 downstream targets of cyclin-dependent kinase 4, a cell cycle regulator, while upregulating protein expression of p53. We further revealed that miR-218 induced apoptosis (P < 0.01), inhibited cell proliferation (P < 0.05) and promoted cell cycle arrest in the G2 phase (P < 0.01). In conclusion, miR-218 plays a pivotal role in CRC development through inhibiting cell proliferation and cycle progression and promoting apoptosis by downregulating BMI-1.
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Affiliation(s)
- Xinqi He
- Institute of Digestive Disease and Department of Medicine and Therapeutics, Li Ka Shing Institute of Health Sciences, Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
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22
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Singhal J, Nagaprashantha LD, Vatsyayan R, Ashutosh, Awasthi S, Singhal SS. Didymin induces apoptosis by inhibiting N-Myc and upregulating RKIP in neuroblastoma. Cancer Prev Res (Phila) 2011; 5:473-83. [PMID: 22174364 DOI: 10.1158/1940-6207.capr-11-0318] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Neuroblastomas arise from the neural crest cells and represent the most common solid tumors outside the nervous system in children. The amplification of N-Myc plays a primary role in the pathogenesis of neuroblastomas, whereas acquired mutations of p53 lead to refractory and relapsed cases of neuroblastomas. In this regard, dietary compounds which can target N-Myc and exert anticancer effects independent of p53 status acquire significance in the management of neuroblastomas. Hence, we investigated the anticancer properties of the flavonoid didymin in neuroblastomas. Didymin effectively inhibited proliferation and induced apoptosis irrespective of p53 status in neuroblastomas. Didymin downregulated phosphoinositide 3-kinase, pAkt, Akt, vimentin, and upregulated RKIP levels. Didymin induced G(2)/M arrest along with decreasing the levels of cyclin D1, CDK4, and cyclin B1. Importantly, didymin inhibited N-Myc as confirmed at protein, mRNA, and transcriptional level by promoter-reporter assays. High-performance liquid chromatography analysis of didymin-treated (2 mg/kg b.w.) mice serum revealed effective oral absorption with free didymin concentration of 2.1 μmol/L. Further in vivo mice xenograft studies revealed that didymin-treated (2 mg/kg b.w.) animals had significant reductions in tumors size compared with controls. Didymin strongly inhibited the proliferation (Ki67) and angiogenesis (CD31) markers, as well as N-Myc expression, as revealed by the histopathologic examination of paraffin-embedded section of resected tumors. Collectively, our in vitro and in vivo studies elucidated the anticancer properties and mechanisms of action of a novel, orally active, and palatable flavonoid didymin, which makes it a potential new approach for neuroblastoma therapy (NANT) to target pediatric neuroblastomas.
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Affiliation(s)
- Jyotsana Singhal
- Department of Diabetes and Metabolic Disease Research, National Medical Center, Beckman Research Institute, City of Hope, Duarte, CA 91010, USA
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23
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Giles N, Pavey S, Pinder A, Gabrielli B. Multiple melanoma susceptibility factors function in an ultraviolet radiation response pathway in skin. Br J Dermatol 2011; 166:362-71. [DOI: 10.1111/j.1365-2133.2011.10635.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Anti-cancer effects of novel flavonoid vicenin-2 as a single agent and in synergistic combination with docetaxel in prostate cancer. Biochem Pharmacol 2011; 82:1100-9. [PMID: 21803027 DOI: 10.1016/j.bcp.2011.07.078] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Revised: 07/14/2011] [Accepted: 07/15/2011] [Indexed: 12/20/2022]
Abstract
The present study was conducted to determine the efficacy of novel flavonoid vicenin-2 (VCN-2), an active constituent of the medicinal herb Ocimum Sanctum Linn or Tulsi, as a single agent and in combination with docetaxel (DTL) in carcinoma of prostate (CaP). VCN-2 effectively induced anti-proliferative, anti-angiogenic and pro-apoptotic effect in CaP cells (PC-3, DU-145 and LNCaP) irrespective of their androgen responsiveness or p53 status. VCN-2 inhibited EGFR/Akt/mTOR/p70S6K pathway along with decreasing c-Myc, cyclin D1, cyclin B1, CDK4, PCNA and hTERT in vitro. VCN-2 reached a level of 2.6±0.3μmol/l in serum after oral administration in mice which reflected that VCN-2 is orally absorbed. The i.v. administration of docetaxel (DTL), current drug of choice in androgen-independent CaP, is associated with dose-limiting toxicities like febrile neutropenia which has lead to characterization of alternate routes of administration and potential combinatorial regimens. In this regard, VCN-2 in combination with DTL synergistically inhibited the growth of prostate tumors in vivo with a greater decrease in the levels of AR, pIGF1R, pAkt, PCNA, cyclin D1, Ki67, CD31, and increase in E-cadherin. VCN-2 has been investigated for radioprotection and anti-inflammatory properties. This is the first study on the anti-cancer effects of VCN-2. In conclusion, our investigations collectively provide strong evidence that VCN-2 is effective against CaP progression along with indicating that VCN-2 and DTL co-administration is more effective than either of the single agents in androgen-independent prostate cancer.
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Nagaprashantha LD, Vatsyayan R, Singhal J, Lelsani P, Prokai L, Awasthi S, Singhal SS. 2'-hydroxyflavanone inhibits proliferation, tumor vascularization and promotes normal differentiation in VHL-mutant renal cell carcinoma. Carcinogenesis 2011; 32:568-75. [PMID: 21304051 DOI: 10.1093/carcin/bgr021] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Renal cell carcinoma (RCC) is one of the top ten cancers prevalent in USA. Loss-of-function mutations in the von Hippel-Lindau (VHL) gene constitute an established risk factor contributing to 75% of total reported cases of RCC. Loss-of-VHL leads to a highly vascularized phenotype of renal tumors. Intake of citrus fruits has been proven to reduce the risk of RCC in multicenter international studies. Hence, we studied the effect of 2'-hydroxyflavanone (2HF), an active anticancer compound from oranges, in RCC. Our in vitro investigations revealed that 2HF suppresses VHL-mutant RCC to a significantly greater extent than VHL-wild-type RCC by inhibiting epidermal growth factor receptor signaling, which is increased due to VHL mutations in RCC. Our results also revealed for the first time, that 2HF inhibits glutathione S-transferase pi activity. 2HF reduced cyclin B1 and CDK4 levels and induced G2/M phase arrest in VHL-mutant RCC. Importantly, 2HF inhibited the angiogenesis in VHL-mutant RCC by decreasing vascular endothelial growth factor expression. Our in vivo studies in mice xenografts confirmed our in vitro results as evident by decreased levels of proliferation marker, Ki67 and angiogenic marker, CD31, in 2HF-treated mice xenografts of VHL-mutant RCC. 2HF also increased the expression of E-cadherin in VHL-mutant RCC, which would be of significance in restoring normal epithelial phenotype. Collectively, our in vitro and in vivo results revealed the potent antiproliferative, anti-angiogenic and prodifferentiation properties of 2HF in VHL-mutant RCC, sparing normal cells, which could have significant implications not only in the specific management of VHL-mutant RCC but also towards other VHL syndromes.
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26
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Qiu P, Dong P, Guan H, Li S, Ho CT, Pan MH, McClements DJ, Xiao H. Inhibitory effects of 5-hydroxy polymethoxyflavones on colon cancer cells. Mol Nutr Food Res 2010; 54 Suppl 2:S244-52. [PMID: 20397199 DOI: 10.1002/mnfr.200900605] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Hydroxylated polymethoxyflavones (PMFs) are a class of novel flavonoid compounds mainly found in citrus plants. We studied the effects of three major 5-hydroxy PMFs, namely: 5-hydroxy-6,7,8,3',4'-pentamethoxyflavone, 5-hydroxy-3,6,7,8,3',4'-hexamethoxyflavone, and 5-hydroxy-6,7,8,4'-tetramethoxyflavone, on human colon cancer HCT116 and HT29 cells. Their effects were compared with those produced by their permethoxylated counterparts, namely: nobiletin, 3,5,6,7,8,3',4'-heptamethoxylflavone, and tangeretin. 5-Hydroxy PMFs showed much stronger inhibitory effects on the growth of the colon cancer cells in comparison with their permethoxylated counterparts, suggesting the pivotal role of hydroxyl group at 5-position in the enhanced inhibitory activity by 5-hydroxy PMFs. Flow cytometry analysis demonstrated that three 5-hydroxy PMFs produced different effects on the cell cycle and apoptosis, which may suggest that three 5-hydroxy PMFs act through different mechanisms. For example, 5-hydroxy-6,7,8,3',4'-pentamethoxyflavone caused cell cycle arrest at G2/M phase in HT29 cells, while 5-hydroxy-3,6,7,8,3',4'-hexamethoxyflavone led to significant G0/G1 phase arrest. In contrast, 5-hydroxy-6,7,8,4'-tetramethoxyflavone increased sub-G0/G1 cell population, which has been confirmed to be due to enhanced apoptosis. Our results further demonstrated that the inhibitory effects of 5-hydroxy PMFs were associated with their ability in modulating key signaling proteins related to cell proliferation and apoptosis, such as p21(Cip1/Waf1), CDK-2, CDK-4, phosphor-Rb, Mcl-1, caspases 3 and 8, and poly ADP ribose polymerase (PARP).
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Affiliation(s)
- Peiju Qiu
- Marine Drug and Food Institute, Ocean University of China, Qingdao Shandong, P R China
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27
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Maity B, Yang J, Huang J, Askeland RW, Bera S, Fisher RA. Regulator of G protein signaling 6 (RGS6) induces apoptosis via a mitochondrial-dependent pathway not involving its GTPase-activating protein activity. J Biol Chem 2010; 286:1409-19. [PMID: 21041304 DOI: 10.1074/jbc.m110.186700] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Regulator of G protein signaling 6 (RGS6) is a member of a family of proteins called RGS proteins, which function as GTPase-activating proteins (GAPs) for Gα subunits. Given the role of RGS6 as a G protein GAP, the link between G protein activation and cancer, and a reduction of cancer risk in humans expressing a RGS6 SNP leading to its increased translation, we hypothesized that RGS6 might function to inhibit growth of cancer cells. Here, we show a marked down-regulation of RGS6 in human mammary ductal epithelial cells that correlates with the progression of their transformation. RGS6 exhibited impressive antiproliferative actions in breast cancer cells, including inhibition of cell growth and colony formation and induction of cell cycle arrest and apoptosis by mechanisms independent of p53. RGS6 activated the intrinsic pathway of apoptosis involving regulation of Bax/Bcl-2, mitochondrial outer membrane permeabilization (MOMP), cytochrome c release, activation of caspases-3 and -9, and poly(ADP-ribose) polymerase cleavage. RGS6 promoted loss of mitochondrial membrane potential (ΔΨ(m)) and increases in reactive oxygen species (ROS). RGS6-induced caspase activation and loss of ΔΨ(m) was mediated by ROS, suggesting an amplification loop in which ROS provided a feed forward signal to induce MOMP, caspase activation, and cell death. Loss of RGS6 in mouse embryonic fibroblasts dramatically impaired doxorubicin-induced growth suppression and apoptosis. Surprisingly, RGS6-induced apoptosis in both breast cancer cells and mouse embryonic fibroblasts does not require its GAP activity toward G proteins. This work demonstrates a novel signaling action of RGS6 in cell death pathways and identifies it as a possible therapeutic target for treatment of breast cancer.
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Affiliation(s)
- Biswanath Maity
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242, USA
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Abou EL-Ela M, Nagui N, Mahgoub D, El-Eishi N, Fawzy M, El-Tawdy A, Abdel Hay R, Rashed L. Expression of cyclin D1 and p16 in psoriasis before and after phototherapy. Clin Exp Dermatol 2010; 35:781-5. [DOI: 10.1111/j.1365-2230.2009.03774.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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29
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Wu J, Zhang YC, Suo WH, Liu XB, Shen WW, Tian H, Fu GH. Induction of anion exchanger-1 translation and its opposite roles in the carcinogenesis of gastric cancer cells and differentiation of K562 cells. Oncogene 2010; 29:1987-96. [PMID: 20062076 DOI: 10.1038/onc.2009.481] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Anion exchanger-1 (AE1), an erythroid-specific membrane protein, mediates the Cl(-)/HCO(-)(3) exchange across the plasma membrane and regulates intracellular pH. We have found that AE1 was unexpectedly expressed in gastric cancer cells and participated in the tumorigenesis of the cancer. Here, we focus on the induction of AE1 expression and its role in gastric carcinogenesis as well as in the differentiation of K562 cells. The results show that expression of AE1 is not related to genetic mutation or the mRNA level, but rather, that it is modulated by miR-24. miR-24 decreases the expression of AE1 through binding to the 3'UTR of AE1 mRNA. Transfection of an miR-24 into gastric cancer cells reduced the elevation of the AE1 protein, which resulted in return of AE1-sequestrated p16 to the nucleus, thereby inhibiting proliferation of the cells. Furthermore, the miR-24 inhibitor cooperated with hemin to induce the expression of AE1 in K562 cells and differentiation of the cells, which is consistent with results obtained from the cells cultured at pH 7.6 or from forced stable expression of AE1. These findings establish a novel regulation of miR-24-related AE1 expression in gastric carcinogenesis and erythropoiesis.
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Affiliation(s)
- J Wu
- Department of Pathology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, PR China
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30
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Jin YS, Seong ES, Qu GZ, Han W, Yoon BS, Wang MH. Cloning and morphological properties of Nicgl;CYCD3;1 gene in genetic tumors from interspecific hybrid of N. langsdorffii and N. glauca. JOURNAL OF PLANT PHYSIOLOGY 2007; 165:317-23. [PMID: 17566604 DOI: 10.1016/j.jplph.2006.12.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2006] [Revised: 12/05/2006] [Accepted: 12/11/2006] [Indexed: 05/15/2023]
Abstract
Plant genetic tumors represent neoplastic growths, which arise spontaneously in hybrid plants without apparent external induction. To understand the molecular nature of unregulated cell proliferation, a cyclin D cDNA clone encoding a cyclin D of 1104bp was isolated from a genetic tumor and designated Nicgl;CYCD3;1 gene. DNA gel blot analysis suggested that there are two copies of Nicgl;CYCD3;1 in the genetic tumors. Northern analysis showed that this gene had the highest expression level in genetic tumor compared to Nicotiana glauca, N. langsdorffii and hybrid plants. Plant morphology of hybrid plant was an intermediate between N. glauca and N. langsdorffii and was altered in the genetic tumors. The cell cycle distribution in N. glauca was G0/G1, 90.59; S, 0.60; G2/M, 8.81; in N. langsdorffii it was G 0/G1, 86.22; S, 6.90; G2/M, 6.88; in hybrid plants it was G 0/G1, 96.40; S, 1.79; G2/M, 1.81; and in genetic tumors G 0/G1, 74.70; S, 2.35; G2/M, 22.94. These data provide new insights into the molecular mechanisms underlying genetic tumor formation from interspecific hybrid between N. langsdorffii and N. glauca.
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Affiliation(s)
- Ying Shan Jin
- School of Biotechnology, Kangwon National University, Chuncheon, Kangwon-do, 200-701, Republic of Korea
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31
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Pilkinton M, Sandoval R, Colamonici OR. Mammalian Mip/LIN-9 interacts with either the p107, p130/E2F4 repressor complex or B-Myb in a cell cycle-phase-dependent context distinct from the Drosophila dREAM complex. Oncogene 2007; 26:7535-43. [PMID: 17563750 DOI: 10.1038/sj.onc.1210562] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Mammalian Mip/LIN-9 is a cell cycle regulatory protein that is negatively regulated by CDK4/cyclin D. It has been demonstrated that Mip/LIN-9 collaborates with B-Myb during S and G(2)/M in the induction of cyclins A and B, and CDK1. The ortholog of Mip/LIN-9 in Drosophila, Mip130, is part of a large multisubunit protein complex that includes RBF, repressor E2Fs and Myb, in what was termed the dREAM complex. A similar complex, although lacking B-Myb, was also described in Caenorhabditis elegans. Here, we demonstrate that unlike Drosophila, Mip/LIN-9 has mutually exclusive and cell cycle-phase-specific interactions with the mammalian orthologs of the dREAM complex. In G(0)/early G(1), Mip/LIN-9 forms a complex with E2F4 and p107 or p130, while in late G(1)/S phase, it associates with B-Myb. The separation of Mip/LIN-9 from p107,p130/E2F4 is likely driven by phosphorylation of the pocket proteins by CDK4 since Mip/LIN-9 fails to interact with phosphorylated forms of p107,p130. Importantly, the repressor complex that Mip/LIN-9 forms with p107 takes functional precedence over the transcriptional activation linked to the Mip/LIN-9 and B-Myb interaction since expression of p107 blocks the activation of the cyclin B promoter triggered by B-Myb and Mip/LIN-9.
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Affiliation(s)
- M Pilkinton
- Department of Pharmacology, University of Illinois, Chicago, IL 60612, USA
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32
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Tagliati F, Zatelli MC, Bottoni A, Piccin D, Luchin A, Culler MD, Degli Uberti EC. Role of complex cyclin d1/cdk4 in somatostatin subtype 2 receptor-mediated inhibition of cell proliferation of a medullary thyroid carcinoma cell line in vitro. Endocrinology 2006; 147:3530-8. [PMID: 16601140 DOI: 10.1210/en.2005-1479] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Somatostatin (SRIH) inhibits cell proliferation by interacting with five distinct SRIH receptor subtypes (SSTRs) activating several pathways in many tissues. We previously demonstrated that SRIH, by activating Src homology-2-containing protein, inhibits cell proliferation of the human medullary thyroid carcinoma cell line, TT, which expresses all SSTRs. However, the effects of SRIH on cell cycle proteins have not been investigated so far. We therefore evaluated the effects of SRIH and a selective SSTR2 agonist on cell cycle protein expression, mainly focusing on cyclin D1 and its associated kinases. Our data show that SRIH and the selective SSTR2 agonist, BIM-23120, reduce cell proliferation and DNA synthesis as well as induce a delay of the cell cycle in G(2)/M phase. Moreover, treatment with both SRIH and BIM-23120 decreases cyclin D1 levels, with a parallel increase in phosphocyclin D1 levels, suggesting protein degradation. Moreover, our data show an increase in glycogen synthase kinase-3beta activity, which triggers phosphorylation-dependent cyclin D1 degradation. Indeed, we observed a reduction in cyclin D1 protein half-life under treatment with SRIH or the SSTR2 selective agonist. A reduction in cdk4 protein levels is also observed with a parallel reduction in Rb phosphorylation levels at Ser-780. Our data indicate that the subtype 2 receptor-mediated antiproliferative effect of SRIH on TT cell proliferation may be exerted through a decrease in cyclin D1 levels.
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Affiliation(s)
- Federico Tagliati
- Section of Endocrinology, Department of Biomedical Sciences and Advanced Therapies, University of Ferrara, Via Savonarola 9, 44100 Ferrara, Italy
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Abstract
Cyclins are the regulatory subunits of kinases that control progress through the cell cycle. This review focuses on cyclins that are targets for extracellular signaling and frequently deregulated during oncogenesis, particularly cyclin D1. Receptor tyrosine kinases and adhesion molecules act through various effector pathways to modulate cyclin D1 abundance at multiple levels including transcription, translation and protein stability. In contrast, cyclin E-Cdk2 activity appears to be more commonly regulated by means other than regulation of cyclin E abundance. The importance of these pathways during oncogenesis is illustrated by the dependence of oncogenes such as Ras and Neu/ErbB2 on cyclin D1. Thus, understanding the roles of cyclins in growth factor and adhesion signaling is important for understanding the biology of both normal and neoplastic cells.
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Affiliation(s)
- Elizabeth A Musgrove
- Cancer Research Program, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia.
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Burgess A, Wigan M, Giles N, Depinto W, Gillespie P, Stevens F, Gabrielli B. Inhibition of S/G2 phase CDK4 reduces mitotic fidelity. J Biol Chem 2006; 281:9987-95. [PMID: 16476733 DOI: 10.1074/jbc.m512714200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cyclin-dependent kinase 4 (CDK4)/cyclin D has a key role in regulating progression through late G(1) into S phase of the cell cycle. CDK4-cyclin D complexes then persist through the latter phases of the cell cycle, although little is known about their potential roles. We have developed small molecule inhibitors that are highly selective for CDK4 and have used these to define a role for CDK4-cyclin D in G(2) phase. The addition of the CDK4 inhibitor or small interfering RNA knockdown of cyclin D3, the cyclin D partner, delayed progression through G(2) phase and mitosis. The G(2) phase delay was independent of ATM/ATR and p38 MAPK but associated with elevated Wee1. The mitotic delay was because of failure of chromosomes to migrate to the metaphase plate. However, cells eventually exited mitosis, with a resultant increase in cells with multiple or micronuclei. Inhibiting CDK4 delayed the expression of the chromosomal passenger proteins survivin and borealin, although this was unlikely to account for the mitotic phenotype. These data provide evidence for a novel function for CDK4-cyclin D3 activity in S and G(2) phase that is critical for G(2)/M progression and the fidelity of mitosis.
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Affiliation(s)
- Andrew Burgess
- Cancer Biology Program, Centre for Immunology and Cancer Research, University of Queensland, Princess Alexandra Hospital, Brisbane, Queensland 4102, Australia
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35
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Tagliati F, Bottoni A, Bosetti A, Zatelli MC, degli Uberti EC. Utilization of luminescent technology to develop a kinase assay: Cdk4 as a model system. J Pharm Biomed Anal 2006; 39:811-4. [PMID: 15955655 DOI: 10.1016/j.jpba.2005.05.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2005] [Revised: 05/03/2005] [Accepted: 05/04/2005] [Indexed: 11/27/2022]
Abstract
Protocols to assess kinase activity generally include radioactive methods, fluorescent polarization technology and the use of specific antibodies. Here, a simple, effective, non radioactive method to measure kinase activity of immunoprecipitated proteins is described. Cdk4, a cell cycle dependent enzyme, was immunoprecipitated from whole cell extracts and used in kinase reactions. This system has been developed taking advantage of the kinase-Glo reagent (Promega), based on ATP depletion technology, but with a wider range of applications. The original aim of the commercial kit is the evaluation of kinase activity of highly purified enzymes, while this system enabled the evaluation of native kinases, retrieved by immunoprecipitation. This method was highly homogeneous and did not require any kind of separation or purification as well. Moreover, it was suitable for basic research and may be useful for low-medium throughput pharmaceutical screening of chemical libraries.
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Affiliation(s)
- Federico Tagliati
- Section of Endocrinology, Department of Biomedical Sciences and Advanced Therapies, University of Ferrara, Via Savonarola 9, 44100 Ferrara, Italy
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36
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Jian Y, Yan J, Wang H, Chen C, Sun M, Jiang J, Lu J, Yang Y, Gu J. Cyclin D3 interacts with vitamin D receptor and regulates its transcription activity. Biochem Biophys Res Commun 2005; 335:739-48. [PMID: 16105657 DOI: 10.1016/j.bbrc.2005.07.141] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2005] [Accepted: 07/23/2005] [Indexed: 11/26/2022]
Abstract
D-type cyclins are essential for the progression through the G1 phase of the cell cycle. Besides serving as cell cycle regulators, D-type cyclins were recently reported to have transcription regulation functions. Here, we report that cyclin D3 is a new interacting partner of vitamin D receptor (VDR), a member of the superfamily of nuclear receptors for steroid hormones, thyroid hormone, and the fat-soluble vitamins A and D. The interaction was confirmed with methods of yeast two-hybrid system, in vitro binding analysis and in vivo co-immunoprecipitation. Cyclin D3 interacted with VDR in a ligand-independent manner, but treatment of the ligand, 1,25-dihydroxyvitamin D3, strengthened the interaction. Confocal microscopy analysis showed that ligand-activated VDR led to an accumulation of cyclin D3 in the nuclear region. Cyclin D3 up-regulated transcriptional activity of VDR and this effect was counteracted by overexpression of CDK4 and CDK6. These findings provide us a new clue to understand the transcription regulation functions of D-type cyclins.
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Affiliation(s)
- Yongzhi Jian
- State Key Laboratory of Genetic Engineering and Gene Research Center, Shanghai Medical College of Fudan University, Shanghai 200032, PR China
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37
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Lange S, Viergutz T, Simkó M. Modifications in cell cycle kinetics and in expression of G1 phase-regulating proteins in human amniotic cells after exposure to electromagnetic fields and ionizing radiation. Cell Prolif 2004; 37:337-49. [PMID: 15377333 PMCID: PMC6496295 DOI: 10.1111/j.1365-2184.2004.00317.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Low-frequency electromagnetic fields are suspected of being involved in carcinogenesis, particularly in processes that could be related to cancer promotion. Because development of cancer is associated with deregulated cell growth and we previously observed a magnetic field-induced decrease in DNA synthesis [Lange et al. (2002) Alterations in the cell cycle and in the protein level of cyclin D1p, 21CIP1, and p16INK4a after exposure to 50 HZ. MF in human cells. Radiat. Environ. Biophys.41, 131], this study aims to document the influence of 50 Hz, 1 mT magnetic fields (MF), with or without initial gamma-ionizing radiation (IR), on the following cell proliferation-relevant parameters in human amniotic fluid cells (AFC): cell cycle distribution, expression of the G1 phase-regulating proteins Cdk4, cyclin D1, p21CIP1 and p16INK4a, and Cdk4 activity. While IR induced a G1 delay and a dose-dependent G2 arrest, no discernible changes in cell cycle kinetics were observed due to MF exposure. However, a significant decrease in the protein expression of cyclin D1 and an increase in p21CIP1- and p16INK4a-expression could be detected after exposure to MF alone. IR-exposure caused an augmentation of p21CIP1- and p16INK4a- levels as well, but did not alter cyclin D1 expression. A slight diminution of Cdk4 activity was noticed after MF exposure only, indicating that Cdk4 appears not to act as a mediator of MF- or IR-induced changes in the cell cycle of AFC cells. Co-exposure to MF/IR affected neither cell cycle distribution nor protein expression or kinase activity additionally or synergistically, and therefore MF seems not to modify the mutagenic potency of IR.
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Affiliation(s)
- S Lange
- Research Centre Rossendorf, Institute of Bioinorganic and Radiopharmaceutical Chemistry, Dresden, Germany
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38
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Liu W, Sun M, Jiang J, Shen X, Sun Q, Liu W, Shen H, Gu J. Cyclin D3 interacts with human activating transcription factor 5 and potentiates its transcription activity. Biochem Biophys Res Commun 2004; 321:954-60. [PMID: 15358120 DOI: 10.1016/j.bbrc.2004.07.053] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2004] [Indexed: 11/17/2022]
Abstract
The Cyclin D3 protein is a member of the D-type cyclins. Besides serving as cell cycle regulators, D-type cyclins have been reported to be able to interact with several transcription factors and modulate their transcriptional activations. Here we report that human activating transcription factor 5 (hATF5) is a new interacting partner of Cyclin D3. The interaction was confirmed by in vivo coimmunoprecipitation and in vitro binding analysis. Neither interaction between Cyclin D1 and hATF5 nor interaction between Cyclin D2 and hATF5 was observed. Confocal microscopy analysis showed that Cyclin D3 could colocalize with hATF5 in the nuclear region. Cyclin D3 could potentiate hATF5 transcriptional activity independently of its Cdk4 partner. But Cyclin D1 and Cyclin D2 had no effect on hATF5 transcriptional activity. These data provide a new clue to understand the new role of Cyclin D3 as a transcriptional regulator.
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Affiliation(s)
- Wenjin Liu
- State Key Laboratory of Genetic Engineering and Gene Research Center, Shanghai Medical College of Fudan University, Shanghai 200032, People's Republic of China
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39
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Faast R, White J, Cartwright P, Crocker L, Sarcevic B, Dalton S. Cdk6-cyclin D3 activity in murine ES cells is resistant to inhibition by p16(INK4a). Oncogene 2004; 23:491-502. [PMID: 14724578 DOI: 10.1038/sj.onc.1207133] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Through a screen aimed at identifying genes that are specifically upregulated in embryomic stem (ES) cells but not primitive ectoderm, we identified cyclin D3. This was surprising since cyclin D activity is generally believed to be inactive in ES cells even though retinoblastoma tumor suppressor protein (pRb) accumulates in a predominantly hyperphosphorylated state. Cdk6 is the major catalytic partner for cyclin D3 in ES cells and exhibits robust pRb kinase activity that is downregulated during the early stages of ES embryoid body differentiation. To investigate the basis underlying the insensitivity of ES cells to ectopic p16 expression, we show that Cdk6-cyclin D3 complexes are not subject to inhibition by p16, similar to Cdk-viral cyclin complexes. These observations show that specificity exists between Cdk4/6-cyclin D complexes and their ability to be targeted by p16. Our data suggest that Cdk6-cyclin D3 activity in other cell types, including tumors, may also be refractory to p16-mediated growth inhibition and raises the possibility of additional specificity within the INK4 family.
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Affiliation(s)
- Renate Faast
- Department of Molecular Biosciences, BresaGen Cell Therapy Program, Center for Molecular Genetics of Development, University of Adelaide, Adelaide, South Australia, Australia
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40
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Cao MY, Lee Y, Feng NP, Al-Qawasmeh RA, Viau S, Gu XP, Lau L, Jin H, Wang M, Vassilakos A, Wright JA, Young AH. NC381, a Novel Anticancer Agent, Arrests the Cell Cycle in G0-G1 and Inhibits Lung Tumor Cell Growth in Vitro and in Vivo. J Pharmacol Exp Ther 2003; 308:538-46. [PMID: 14610220 DOI: 10.1124/jpet.103.059618] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Although clotrimazole (CLT), an antifungal drug, inhibits tumor cell proliferation and angiogenesis, its clinical application is hampered by significant hepatotoxicity due to the presence of an imidazole moiety. In our attempts to develop CLT analogs that are devoid of imidazole and are as efficacious as CLT, one pharmacophore designated NC381 was generated and shown to inhibit tumor cell growth via a mechanism similar to that of CLT. In vitro, treatment of NCI-H460 nonsmall cell lung cancer (NSCLC) cells with NC381 inhibited growth in a time-dependent manner. Flow cytometric analysis demonstrated that the decrease in cell growth was associated with inhibition of cell cycle progression at the G(1)-S phase transition, resulting in G(0)-G(1) arrest. There was a concomitant inhibition of cyclin D1 expression and subsequent reduction in the formation of the cyclin D1-CDK4 complex. Consistent with a decrease in the cyclin D1-CDK4 complex, NC381 treatment resulted in significant inhibition of pRb phosphorylation. There also were changes in the activity of cell cycle-related proteins, including p16(Ink4) and p27(Kip1). Together, these results are consistent with a model in which NC381 arrests cell cycle progression via inhibition of the pathway that promotes exit from the G(1) phase of the cell cycle. Furthermore, the clinical applicability of NC381 was evaluated in an in vivo murine xenograft model of human NSCLC (NCI-H460). NC381 treatment resulted in significant inhibition of tumor growth. Given the poor prognosis and the limited treatment options available, the present results underscore the potential of NC381 in the treatment of human NSCLC.
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Affiliation(s)
- Ming-Yu Cao
- Lorus Therapeutics Inc., Toronto, ON, Canada, M9W 4Z7.
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41
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Abstract
Many cancers are the pathological consequence of environmentally initiated disruptions to cellular genetic control mechanisms. For most cancers the relevant environmental carcinogens have not been identified, but one major exception is cutaneous malignant melanoma, for which the primary environmental agent is solar ultraviolet (UV) radiation. Hence, melanomagenesis represents a potential model of detrimental gene-environment interaction. Although the underlying genetic basis of melanoma is currently being elucidated, fundamental questions concerning UV and the mechanisms by which it operates remain unanswered. Significant progress has recently been made in creating UV-responsive, genetically tractable mouse models of melanoma that accurately recapitulate human disease. These models are providing novel insights into how the genome and environment interact in vivo.
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Affiliation(s)
- Glenn Merlino
- Laboratory of Molecular Biology, National Cancer Institute, Building 37, Room 5002, Bethesda, MD 20892-4264, USA.
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42
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Miralem T, Avraham HK. Extracellular matrix enhances heregulin-dependent BRCA1 phosphorylation and suppresses BRCA1 expression through its C terminus. Mol Cell Biol 2003; 23:579-93. [PMID: 12509456 PMCID: PMC151527 DOI: 10.1128/mcb.23.2.579-593.2003] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Germ line mutations in the breast cancer susceptibility gene BRCA1 account for the increased risk of early onset of familial breast cancer, whereas overexpression of the ErbB family of receptor tyrosine kinases has been linked to the development of nonfamilial or sporadic breast cancer. To analyze whether there is a link between these two regulatory molecules, we studied the effects of ErbB-2 activation by heregulin (HRG) on BRCA1 function. It was previously demonstrated that HRG induced the phosphorylation of BRCA1, which was mediated by the phosphatidylinositol 3-kinase (PI3K)/Akt pathway. Since altered interaction between cells and the surrounding extracellular matrix (ECM) is a common feature in a variety of tumors and since ECM modulates intracellular signaling, we hypothesized that ECM may affect the expression and HRG-dependent phosphorylation of BRCA1. Following stimulation by HRG, a strong increase in [(3)H]thymidine incorporation was observed in human T47D breast cancer cells seeded on plastic (PL). When T47D cells were seeded on laminin (LAM) or Matrigel, HRG induced a significantly higher proliferation than it did in cells seeded on PL. T47D cells seeded on poly-L-lysine had an abrogated mitogenic response, indicating the involvement of integrins in this process. HRG treatment induced a transient phosphorylation of BRCA1 that was enhanced in T47D cells grown on LAM. LAM-enhanced BRCA1 phosphorylation was mediated through alpha(6) integrin upon HRG stimulation. Accordingly, T47D cells grown on LAM had the greatest increase in ErbB-2 activation, PI3K activity, and phosphorylation of Akt. A similar pattern of BRCA1 mRNA expression was observed when T47D cells were seeded on PL, LAM, or COL4. There was a significant decrease in the steady state of the BRCA1 mRNA level on both the LAM and COL4 matrices compared to that for cells seeded on PL. In addition, HRG stimulation caused a significant decrease in BRCA1 mRNA expression that was dependent on protein synthesis. Pretreatment with both the calpain inhibitor ALLN (N-acetyl-Leu-Leu-norleucinal) and the proteosome inhibitor lactacystin inhibited the HRG-induced down-regulation of BRCA1 mRNA expression. Likewise, there was a strong decrease in the protein level of BRCA1 in T47D cells 4 h after treatment with HRG compared to its level in control nontreated T47D cells. Pretreatment with the proteosome inhibitors ALLN, lactacystin, and PSI [N-benzyloxycarbonyl-Ile-Glu-(O-t-butyl)-Ala-leucinal] inhibited also the HRG-induced down-regulation of BRCA1 protein in breast cancer cells. Interestingly, BRCA1 mRNA expression in HCC-1937 breast cancer cells, which express C-terminally truncated BRCA1, was not affected by either LAM or CL4. No phosphorylation of BRCA1 from HCC-1937 cells was observed in response to HRG. While Cdk4 phosphorylated wild-type BRCA1 in response to HRG in T47D cells, Cdk4 failed to phosphorylate the truncated form of BRCA1 in HCC-1937 cells. Furthermore, overexpression of wild-type BRCA1 in HCC-1937 cells resulted in the phosphorylation of BRCA1 and decreased BRCA1 expression upon HRG stimulation while overexpression of truncated BRCA1 in T47D cells resulted in a lack of BRCA1 phosphorylation and restoration of BRCA1 expression. These findings suggest that ECM enhances HRG-dependent BRCA1 phosphorylation and that ECM and HRG down-regulate BRCA1 expression in breast cancer cells. Furthermore, ECM suppresses BRCA1 expression through the C terminus of BRCA1.
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Affiliation(s)
- Tiho Miralem
- Division of Experimental Medicine, Beth Israel-Deaconess Medical Center, Harvard Institutes of Medicine, Boston, Massachusetts 02115, USA
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43
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Santana C, Ortega E, García-Carrancá A. Oncogenic H-ras induces cyclin B1 expression in a p53-independent manner. Mutat Res 2002; 508:49-58. [PMID: 12379461 DOI: 10.1016/s0027-5107(02)00172-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The role of p53 in controlling the G2 checkpoint, in part by repressing cyclin B1 transcription, has been well established. However, accumulating evidence indicate that p53-independent pathways may also play an important role. Ras proteins have been shown to regulate G1/S, but also G2/M transitions. Since cyclin B1/cdc2 complex is the key regulator controlling the G2/M checkpoint, we were interested in addressing if the H-ras oncogene could regulate cyclin B1 expression in a p53-independent manner. We observed an induction of cyclin B1 promoter activity in the presence of H-ras oncogene in SW480 cells, which contain null p53 alleles. In addition, HeLa cells known to express the HPV18 E6 oncogene that inactivates p53, exhibited increased levels of cyclin B1 mRNA and protein when transfected with the H-ras oncogene. Higher expression of cyclin B1 correlated with higher levels of cyclin B1/cdc2 complex and kinase activity that interestingly, showed no inhibition at G2/M after DNA damage. These data suggest that H-ras participates in pathways that regulate cyclin B1 expression and therefore controls the G2/M checkpoint in a p53-independent manner.
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Affiliation(s)
- Carla Santana
- Department of Molecular Biology and Biotechnology, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
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44
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Zhang S, Cai M, Zhang S, Xu S, Chen S, Chen X, Chen C, Gu J. Interaction of p58(PITSLRE), a G2/M-specific protein kinase, with cyclin D3. J Biol Chem 2002; 277:35314-22. [PMID: 12082095 DOI: 10.1074/jbc.m202179200] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The p58(PITSLRE) is a p34(cdc2)-related protein kinase that plays an important role in normal cell cycle progression. Elevated expression of p58(PITSLRE) in eukaryotic cells prevents them from undergoing normal cytokinesis and appears to delay them in late telophase. To investigate the molecular mechanism of p58(PITSLRE) action, we used the yeast two-hybrid system, screened a human fetal liver cDNA library, and identified cyclin D3 as an interacting partner of p58(PITSLRE). In vitro binding assay, in vivo coimmunoprecipitation, and immunofluorescence cell staining further confirmed the association of p58(PITSLRE) with cyclin D3. This binding was observed only in the G(2)/M phase but not in the G(1)/S phase of the cell cycle; meanwhile, no interaction between p110(PITSLRE) and cyclin D3 was observed in all the cell cycle. The overexpression of cyclin D3 in 7721 cells leads to an exclusively accumulation of p58(PITSLRE) in the nuclear region, affecting its cellular distribution. Histone H1 kinase activity of p58(PITSLRE) was greatly enhanced upon interaction with cyclin D3. Furthermore, kinase activity of p58(PITSLRE) was found to increase greatly in the presence of cyclin D3 using a specific substrate, beta-1,4-galactosyltransferase 1. These data provide a new clue to our understanding of the cellular function of p58(PITSLRE) and cyclin D3.
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Affiliation(s)
- Songwen Zhang
- Gene Research Center, Fudan University Medical Center (Former Shanghai Medical University), Shanghai, People's Republic of China 200032
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45
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Chazal M, Marionnet C, Michel L, Mollier K, Dazard JE, Della Valle V, Larsen CJ, Gras MP, Basset-Séguin N. P16(INK4A) is implicated in both the immediate and adaptative response of human keratinocytes to UVB irradiation. Oncogene 2002; 21:2652-61. [PMID: 11965538 DOI: 10.1038/sj.onc.1205349] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2001] [Revised: 01/14/2002] [Accepted: 01/18/2002] [Indexed: 11/09/2022]
Abstract
The p16(INK4A-ARF) locus plays a crucial role in the control of cellular proliferation via both the Rb and P53 pathways. We previously demonstrated that this locus is altered in human skin carcinomas. In the present study we have studied the expression of the p16(INK4A-ARF) locus following UVB irradiation of normal human keratinocytes both at the mRNA (RT-PCR) and at the protein (Western blotting) levels. Our data confirmed that P16(INK4A) protein is induced by UVB at low (30 mJ cm(2)) and high (100 mJ cm(2)) doses and is observed after a single or repeated exposure implying that this response is involved in both the immediate and adaptative response to UVB. The apparent absence of induction p16(INK4A) mRNA suggested that P16(INK4A) protein is upregulated at the post-transcriptional level. Analysis by flow cytometry and BrdU staining indicated that the highest protein level of P16(INK4A) in the cells was associated with a G(2) cell cycle arrest. Comparative analysis of P16(INK4A) and P53 showed that they were differentially modulated in keratinocytes according to the UVB dose and regimen. Low, acute or repeated UVB exposures led to accumulation of both P16(INK4A) and p53, whereas at high UVB doses, P53 and P53-dependent genes were not induced or even downregulated and only a slight but reproducible stabilization of P16(INK4A) protein was observed. In our conditions, P14(ARF) did not seem to participate in the UV response in these cells as P14(ARF) protein did not vary. These results infer that P16(INK4A) plays a role in cell cycle regulation of keratinocytes submitted to UVB irradiation. They also reinforce our previous demonstration of the importance of inactivation of this gene in UV-induced skin carcinogenesis.
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Affiliation(s)
- Marjorie Chazal
- INSERM U532, Institut de Recherche sur la Peau, Pavillon Bazin, Hôpital Saint Louis, 1 avenue C Vellefaux, Paris 75010, France
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46
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Pavey S, Russell T, Gabrielli B. G2 phase cell cycle arrest in human skin following UV irradiation. Oncogene 2001; 20:6103-10. [PMID: 11593418 DOI: 10.1038/sj.onc.1204707] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2001] [Revised: 05/31/2001] [Accepted: 06/08/2001] [Indexed: 11/09/2022]
Abstract
The contribution of the short wavelength ultraviolet (UV) component of sunlight to the aetiology of skin cancer has been widely acknowledged, although its direct contribution to tumour initiation or progression is still poorly understood. The loss of normal cell cycle controls, particularly checkpoint controls, are a common feature of cancer. UV radiation causes both G1 and G2 phase checkpoint arrest in vitro cultured cells. In this study we have investigated the cell cycle responses to suberythemal doses of UV on skin. We have utilized short-term whole organ skin cultures, and multi parameter immunohistochemical and biochemical analysis to demonstrate that basal and suprabasal layer melanocytes and keratinocytes undergo a G2 phase cell cycle arrest for up to 48 h following irradiation. The arrest is associated with increased p16 expression but no apparent p53 involvement. This type of organ culture provides a very useful model system, combining the ease of in vitro manipulation with the ability to perform detailed molecular analysis in a normal tissue environment.
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Affiliation(s)
- S Pavey
- Joint Experimental Oncology Program, Department of Pathology, University of Queensland, Herston Road, Brisbane, Queensland 4006, Australia
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47
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Fry DW, Bedford DC, Harvey PH, Fritsch A, Keller PR, Wu Z, Dobrusin E, Leopold WR, Fattaey A, Garrett MD. Cell cycle and biochemical effects of PD 0183812. A potent inhibitor of the cyclin D-dependent kinases CDK4 and CDK6. J Biol Chem 2001; 276:16617-23. [PMID: 11278443 DOI: 10.1074/jbc.m008867200] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Progression through the G1 phase of the cell cycle requires phosphorylation of the retinoblastoma gene product (pRb) by the cyclin D-dependent kinases CDK4 and CDK6, whose activity can specifically be blocked by the CDK inhibitor p16(INK4A). Misregulation of the pRb/cyclin D/p16(INK4A) pathway is one of the most common events in human cancer and has lead to the suggestion that inhibition of cyclin D-dependent kinase activity may have therapeutic value as an anticancer treatment. Through screening of a chemical library, we initially identified the [2,3-d]pyridopyrimidines as inhibitors of CDK4. Chemical modification resulted in the identification of PD 0183812 as a potent and highly selective inhibitor of both CDK4 and CDK6 kinase activity, which is competitive with ATP. Flow cytometry experiments showed that of the cell lines tested, only those expressing pRb demonstrated a G1 arrest when treated with PD 0183812. This arrest correlated in terms of incubation time and potency with a loss of pRb phosphorylation and a block in proliferation, which was reversible. These results suggest a potential use of this chemical class of compounds as therapeutic agents in the treatment of tumors with functional pRb, possessing cell cycle aberrations in other members of the pRb/cyclin D/p16(INK4A) pathway.
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Affiliation(s)
- D W Fry
- Department of Cancer Research, Pfizer Global Research and Development, Ann Arbor Laboratories, Ann Arbor, Michigan 48105, USA
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48
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Abstract
Exposure of human fibroblasts to doses of ionizing radiation sufficient to cause a permanent growth arrest repressed the expression of genes induced late during G(0)/G(1)-phase traverse, including both cyclin A and cyclin E. In addition, radiation prevented the cell cycle-dependent activation of cyclin D1-associated kinase activity and the subsequent phosphorylation of the RB tumor suppressor protein. Exposure to radiation did not alter the cellular levels of cyclin D1 protein, nor did it alter the formation of cyclin D1-CDK4 complexes. Surprisingly, the repression of cyclin D1-associated kinase activity in damaged mitogen-stimulated quiescent cells could not be accounted for by a relative increase in the association of CDKN1A (also known as p21(Cip1)) with cyclin D1 complexes, nor was cyclin D1 activity targeted by increased levels of CDKN1A in irradiated, logarithmically growing cultures under conditions where cyclin A activity was acutely repressed. Therefore, a radiation-induced permanent growth arrest is mediated by pathways that are distinct from those that cause cell cycle delay in damaged cells involving repression of cyclin-dependent kinase activity by CDKN1A.
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Affiliation(s)
- J Savell
- Molecular Oncology Program, H. Lee Moffitt Cancer Center and Research Institute, Department of Oncology, University of South Florida College of Medicine, 12902 Magnolia Drive, Tampa, FL 33612, USA
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49
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Goldstone S, Pavey S, Forrest A, Sinnamon J, Gabrielli B. Cdc25-dependent activation of cyclin A/cdk2 is blocked in G2 phase arrested cells independently of ATM/ATR. Oncogene 2001; 20:921-32. [PMID: 11314027 DOI: 10.1038/sj.onc.1204177] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2000] [Revised: 12/06/2000] [Accepted: 12/15/2000] [Indexed: 11/08/2022]
Abstract
Cyclin A/cdk2 is active during S and G2 phases of the cell cycle, but its regulation and function during G2 phase is poorly understood. In this study we have examined the regulation of cyclin A/cdk2 activity during normal G2 phase progression and in genotoxin-induced G2 arrest. We show that cyclin A/cdk2 is activated in early G2 phase by a cdc25 activity. In the G2 phase checkpoint arrest initiated in response to various forms of DNA damage, the cdc25-dependent activation of both cyclin A/cdk2 and cyclin B1/cdc2 is blocked. Ectopic expression of cdc25B, but not cdc25C, in G2 phase arrested cells efficiently activated both cyclin A/cdk2 and cyclin B1/cdc2. Finally, we demonstrate that the block in cyclin A/cdk2 activation in the G2 checkpoint arrest is independent of ATM/ATR. We speculate that the ATM/ATR-independent block in G2 phase cyclin A/cdk2 activation may act as a further layer of checkpoint control, and that blocking G2 phase cyclin A/cdk2 activation contributes to the G2 phase checkpoint arrest.
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Affiliation(s)
- S Goldstone
- Queensland Cancer Fund Research Unit, Queensland Institute of Medical Research, and Joint Experimental Oncology Program, Department of Pathology, University of Queensland, Brisbane, QLD, Australia
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50
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Abstract
Synchronization used to study cell cycle progression may change the characteristics of rapidly proliferating cells. By combining time-lapse, quantitative fluorescent microscopy and microinjection, we have established a method to analyze the cell cycle progression of individual cells without synchronization. This new approach revealed that rapidly growing NIH3T3 cells make a Ras-dependent commitment for completion of the next cell cycle while they are in G2 phase of the preceding cell cycle. Thus, Ras activity during G2 phase induces cyclin D1 expression. This expression continues through the next G1 phase even in the absence of Ras activity, and drives cells into S phase.
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Affiliation(s)
- M Hitomi
- Department of Molecular Biology, The Lerner Research Institute, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
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