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Stout AJ, Arnett MJ, Chai K, Guo T, Liao L, Mirliani AB, Rittenberg ML, Shub M, White EC, Yuen JSK, Zhang X, Kaplan DL. Immortalized Bovine Satellite Cells for Cultured Meat Applications. ACS Synth Biol 2023; 12:1567-1573. [PMID: 37146268 DOI: 10.1021/acssynbio.3c00216] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
For cultured meat to succeed at scale, muscle cells from food-relevant species must be expanded in vitro in a rapid and reliable manner to produce millions of metric tons of biomass annually. Toward this goal, genetically immortalized cells offer substantial benefits over primary cells, including rapid growth, escape from cellular senescence, and consistent starting cell populations for production. Here, we develop genetically immortalized bovine satellite cells (iBSCs) via constitutive expression of bovine Telomerase reverse transcriptase (TERT) and Cyclin-dependent kinase 4 (CDK4). These cells achieve over 120 doublings at the time of publication and maintain their capacity for myogenic differentiation. They therefore offer a valuable tool to the field, enabling further research and development to advance cultured meat.
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Affiliation(s)
- Andrew J Stout
- Tufts University Center for Cellular Agriculture, Tufts University, Medford, Massachusetts 02155, United States
| | - Miles J Arnett
- Tufts University Center for Cellular Agriculture, Tufts University, Medford, Massachusetts 02155, United States
| | - Kristin Chai
- Tufts University Center for Cellular Agriculture, Tufts University, Medford, Massachusetts 02155, United States
| | - Tina Guo
- Tufts University Center for Cellular Agriculture, Tufts University, Medford, Massachusetts 02155, United States
| | - Lishu Liao
- Tufts University Center for Cellular Agriculture, Tufts University, Medford, Massachusetts 02155, United States
| | - Addison B Mirliani
- Tufts University Center for Cellular Agriculture, Tufts University, Medford, Massachusetts 02155, United States
| | - Miriam L Rittenberg
- Tufts University Center for Cellular Agriculture, Tufts University, Medford, Massachusetts 02155, United States
- Biological Engineering Department, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, United States
| | - Michelle Shub
- Tufts University Center for Cellular Agriculture, Tufts University, Medford, Massachusetts 02155, United States
| | - Eugene C White
- Tufts Veterinary Field Service, Cummings School of Veterinary Medicine, Tufts University, North Grafton, Massachusetts 05136, United States
| | - John S K Yuen
- Tufts University Center for Cellular Agriculture, Tufts University, Medford, Massachusetts 02155, United States
| | - Xiaoli Zhang
- Tufts University Center for Cellular Agriculture, Tufts University, Medford, Massachusetts 02155, United States
| | - David L Kaplan
- Tufts University Center for Cellular Agriculture, Tufts University, Medford, Massachusetts 02155, United States
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2
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Butler E, Xu L, Rakheja D, Schwettmann B, Toubbeh S, Guo L, Kim J, Skapek SX, Zheng Y. Exon skipping in genes encoding lineage-defining myogenic transcription factors in rhabdomyosarcoma. Cold Spring Harb Mol Case Stud 2022; 8:mcs.a006190. [PMID: 35933111 PMCID: PMC9528969 DOI: 10.1101/mcs.a006190] [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: 01/05/2022] [Accepted: 07/25/2022] [Indexed: 11/24/2022] Open
Abstract
Rhabdomyosarcoma (RMS) is a childhood sarcoma composed of myoblast-like cells, which suggests a defect in terminal skeletal muscle differentiation. To explore potential defects in the differentiation program, we searched for mRNA splicing variants in genes encoding transcription factors driving skeletal muscle lineage commitment and differentiation. We studied two RMS cases and identified altered splicing resulting in "skipping" the second of three exons in MYOD1. RNA-Seq data from 42 tumors and additional RMS cell lines revealed exon 2 skipping in both MYOD1 and MYF5 but not in MYF6 or MYOG. Complementary molecular analysis of MYOD1 mRNA found evidence for exon skipping in 5 additional RMS cases. Functional studies showed that so-called MYODΔEx2 protein failed to robustly induce muscle-specific genes, and its ectopic expression conferred a selective advantage in cultured fibroblasts and an RMS xenograft. In summary, we present previously unrecognized exon skipping within MYOD1 and MYF5 in RMS, and we propose that alternative splicing can represent a mechanism to alter the function of these two transcription factors in RMS.
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Affiliation(s)
- Erin Butler
- University of Texas Southwestern Medical Center;
| | - Lin Xu
- University of Texas Southwestern Medical Center
| | | | | | | | - Lei Guo
- University of Texas Southwestern Medical Center
| | - Jiwoon Kim
- University of Texas Southwestern Medical Center
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3
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From cyclins to CDKIs: Cell cycle regulation of skeletal muscle stem cell quiescence and activation. Exp Cell Res 2022; 420:113275. [PMID: 35931143 DOI: 10.1016/j.yexcr.2022.113275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 06/12/2022] [Accepted: 07/03/2022] [Indexed: 11/22/2022]
Abstract
After extensive proliferation during development, the adult skeletal muscle cells remain outside the cell cycle, either as post-mitotic myofibers or as quiescent muscle stem cells (MuSCs). Despite its terminally differentiated state, adult skeletal muscle has a remarkable regeneration potential, driven by MuSCs. Upon injury, MuSC quiescence is reversed to support tissue growth and repair and it is re-established after the completion of muscle regeneration. The distinct cell cycle states and transitions observed in the different myogenic populations are orchestrated by elements of the cell cycle machinery. This consists of i) complexes of cyclins and Cyclin-Dependent Kinases (CDKs) that ensure cell cycle progression and ii) their negative regulators, the Cyclin-Dependent Kinase Inhibitors (CDKIs). In this review we discuss the roles of these factors in developmental and adult myogenesis, with a focus on CDKIs that have emerging roles in stem cell functions.
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4
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Morales-Alcala CC, Georgiou IC, Timmis AJ, Riobo-Del Galdo NA. Integral Membrane Protein 2A Is a Negative Regulator of Canonical and Non-Canonical Hedgehog Signalling. Cells 2021; 10:cells10082003. [PMID: 34440772 PMCID: PMC8394137 DOI: 10.3390/cells10082003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 07/27/2021] [Accepted: 08/04/2021] [Indexed: 11/16/2022] Open
Abstract
The Hedgehog (Hh) receptor PTCH1 and the integral membrane protein 2A (ITM2A) inhibit autophagy by reducing autolysosome formation. In this study, we demonstrate that ITM2A physically interacts with PTCH1; however, the two proteins inhibit autophagic flux independently, since silencing of ITM2A did not prevent the accumulation of LC3BII and p62 in PTCH1-overexpressing cells, suggesting that they provide alternative modes to limit autophagy. Knockdown of ITM2A potentiated PTCH1-induced autophagic flux blockade and increased PTCH1 expression, while ITM2A overexpression reduced PTCH1 protein levels, indicating that it is a negative regulator of PTCH1 non-canonical signalling. Our study also revealed that endogenous ITM2A is necessary for timely induction of myogenic differentiation markers in C2C12 cells since partial knockdown delays the timing of differentiation. We also found that basal autophagic flux decreases during myogenic differentiation at the same time that ITM2A expression increases. Given that canonical Hh signalling prevents myogenic differentiation, we investigated the effect of ITM2A on canonical Hh signalling using GLI-luciferase assays. Our findings demonstrate that ITM2A is a strong negative regulator of GLI transcriptional activity and of GLI1 stability. In summary, ITM2A negatively regulates canonical and non-canonical Hh signalling.
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Affiliation(s)
- Cintli C. Morales-Alcala
- Leeds Institute of Medical Research, University of Leeds, Leeds LS2 9JT, UK; (C.C.M.-A.); (I.C.G.)
| | - Ioanna Ch. Georgiou
- Leeds Institute of Medical Research, University of Leeds, Leeds LS2 9JT, UK; (C.C.M.-A.); (I.C.G.)
| | - Alex J. Timmis
- School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK;
| | - Natalia A. Riobo-Del Galdo
- Leeds Institute of Medical Research, University of Leeds, Leeds LS2 9JT, UK; (C.C.M.-A.); (I.C.G.)
- School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK;
- Correspondence: ; Tel.: +44-0113-34-39184
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5
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Cho DS, Doles JD. Skeletal Muscle Progenitor Cell Heterogeneity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1169:179-193. [PMID: 31487024 DOI: 10.1007/978-3-030-24108-7_9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Tissue-specific stem cells contribute to adult tissue maintenance, repair, and regeneration. In skeletal muscle, many different mononuclear cell types are capable of giving rise to differentiated muscle. Of these tissue stem-like cells, satellite cells (SCs) are the most studied muscle stem cell population and are widely considered the main cellular source driving muscle repair and regeneration in adult tissue. Within the satellite cell pool, many distinct subpopulations exist, each exhibiting differential abilities to exit quiescence, expand, differentiate, and self-renew. In this chapter, we discuss the different stem cell types that can give rise to skeletal muscle tissue and then focus on satellite cell heterogeneity during the process of myogenesis/muscle regeneration. Finally, we highlight emerging opportunities to better characterize muscle stem cell heterogeneity, which will ultimately deepen our appreciation of stem cells in muscle development, repair/regeneration, aging, and disease.
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Affiliation(s)
- Dong Seong Cho
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Jason D Doles
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA.
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6
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Mohan A, Asakura A. CDK inhibitors for muscle stem cell differentiation and self-renewal. ACTA ACUST UNITED AC 2017; 6:65-74. [PMID: 28713664 DOI: 10.7600/jpfsm.6.65] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Regeneration of muscle is undertaken by muscle stem cell populations named satellite cells which are normally quiescent or at the G0 phase of the cell cycle. However, upon signals from damaged muscle, satellite cells lose their quiescence, and enter the G1 cell cycle phase to expand the population of satellite cell progenies termed myogenic precursor cells (MPCs). Eventually, MPCs stop their cell cycle and undergo terminal differentiation to form skeletal muscle fibers. Some MPCs retract to quiescent satellite cells as a self-renewal process. Therefore, cell cycle regulation, consisting of satellite cell activation, proliferation, differentiation and self-renewal, is the key event of muscle regeneration. In this review, we summarize up-to-date progress on research about cell cycle regulation of myogenic progenitor cells and muscle stem cells during embryonic myogenesis and adult muscle regeneration, aging, exercise and muscle diseases including muscular dystrophy and muscle fiber atrophy, especially focusing on cyclin-dependent kinase inhibitors (CDKIs).
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Affiliation(s)
- Amrudha Mohan
- Stem Cell Institute, Paul and Sheila Wellstone Muscular Dystrophy Center, Department of Neurology, University of Minnesota Medical School, 2001 6th Street SE, MTRF 4-220, Minneapolis, MN 55455, USA
| | - Atsushi Asakura
- Stem Cell Institute, Paul and Sheila Wellstone Muscular Dystrophy Center, Department of Neurology, University of Minnesota Medical School, 2001 6th Street SE, MTRF 4-220, Minneapolis, MN 55455, USA
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7
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Liu H, Jiang F, Jia X, Lan J, Guo H, Li E, Yan A, Wang Y. Cycling hypoxia affects cell invasion and proliferation through direct regulation of claudin1 / claudin7 expression, and indirect regulation of P18 through claudin7. Oncotarget 2016; 8:10298-10311. [PMID: 28055967 PMCID: PMC5354660 DOI: 10.18632/oncotarget.14397] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 12/05/2016] [Indexed: 12/25/2022] Open
Abstract
Claudins (CLDNs), the major integral membrane proteins at tight junction, play critical roles in apical cell-to-cell adhesion, maintenance of epithelial polarity, and formation of impermeable barriers between epithelial cells.We investigated in this study the expression of CLDNs- Claudin1 (CLDN1) and Claudin7 (CLDN7), and their relation to tumor progression in nasopharyngeal cancer (NPC). CLDN7, rather than CLDN1, showed higher expression in both undifferentiated tumor tissue and the poorly differentiated CNE2 cells, compared with differentiated tissue and the highly differentiated CNE1 cells. Furthermore, knockdown of CLDN7 dramatically inhibited the metastasis and invasion of CNE2 cells suggesting that CLDN7 could act as a biomarker for NPC metastasis.Cycling hypoxia could induce significant changes in CLDN1 and CLDN7 expression in NPC cells. Genetics analysis demonstrated that CLDN1/CLDN7 were not only regulated directly by HIF1a but also affected each other through a feedback mechanism. CLDN7 acted as a bridge to promote HIF1a-induced P18 expression and cell differentiation. Taken together, our results provide evidence that adjusting the oxygenation time and cycles in NPC might be an effective method to prevent / delay the metastasis of poorly differentiated NPC cells.
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Affiliation(s)
- Hong Liu
- 1 Department of Otolaryngology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, China
| | - Feifei Jiang
- 1 Department of Otolaryngology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, China
| | - Xinshan Jia
- 2 Department of Pathology, China Medical University, Shenyang, Liaoning 110001, China
| | - Jing Lan
- 3 Department of Dermatology, China Medical University, Shenyang, Liaoning 110001, China
| | - Hao Guo
- 3 Department of Dermatology, China Medical University, Shenyang, Liaoning 110001, China
| | - Erran Li
- 4 Institute of Respiratory Disease, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, China
| | - Aihui Yan
- 1 Department of Otolaryngology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, China
| | - Yan Wang
- 1 Department of Otolaryngology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, China
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8
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Nomanbhoy TK, Sharma G, Brown H, Wu J, Aban A, Vogeti S, Alemayehu S, Sykes M, Rosenblum JS, Kozarich JW. Chemoproteomic Evaluation of Target Engagement by the Cyclin-Dependent Kinase 4 and 6 Inhibitor Palbociclib Correlates with Cancer Cell Response. Biochemistry 2016; 55:5434-41. [PMID: 27571378 DOI: 10.1021/acs.biochem.6b00629] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Palbociclib is a cyclin-dependent kinase (CDK) 4/CDK6 inhibitor approved for breast cancer that is estrogen receptor (ER)-positive and human epidermal growth factor receptor 2 (HER2)-negative. We profiled palbociclib in cells either sensitive or resistant to the drug using an ATP/ADP probe-based chemoproteomics platform. Palbociclib only engaged CDK4 or CDK6 in sensitive cells. In resistant cells, no inhibition of CDK4 or CDK6 was observed, although the off-target profiles were similar in both cell types. Prolonged incubation of sensitive cells with the compound (24 h) resulted in the downregulation of additional kinases, including kinases critical for cell cycle progression. This downregulation is consistent with cell cycle arrest caused by palbociclib treatment. Both the direct and indirect targets were also observed in a human tumor xenograft study using the COLO-205 cell line in which phosphorylation of the retinoblastoma protein was tracked as the pharmacodyanamic marker. Together, these results suggest that this probe-based approach could be an important strategy toward predicting patient responsiveness to palbociclib.
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Affiliation(s)
- Tyzoon K Nomanbhoy
- ActivX Biosciences , 11025 N. Torrey Pines Road, Suite 120, La Jolla, California 92037, United States
| | - Geeta Sharma
- Agilux Laboratories , Three Biotech, One Innovation Drive, Worcester, Massachusetts 01605, United States
| | - Heidi Brown
- ActivX Biosciences , 11025 N. Torrey Pines Road, Suite 120, La Jolla, California 92037, United States
| | - Jiangyue Wu
- ActivX Biosciences , 11025 N. Torrey Pines Road, Suite 120, La Jolla, California 92037, United States
| | - Arwin Aban
- ActivX Biosciences , 11025 N. Torrey Pines Road, Suite 120, La Jolla, California 92037, United States
| | - Subha Vogeti
- Agilux Laboratories , Three Biotech, One Innovation Drive, Worcester, Massachusetts 01605, United States
| | - Senait Alemayehu
- ActivX Biosciences , 11025 N. Torrey Pines Road, Suite 120, La Jolla, California 92037, United States
| | - Maria Sykes
- ActivX Biosciences , 11025 N. Torrey Pines Road, Suite 120, La Jolla, California 92037, United States
| | - Jonathan S Rosenblum
- ActivX Biosciences , 11025 N. Torrey Pines Road, Suite 120, La Jolla, California 92037, United States
| | - John W Kozarich
- ActivX Biosciences , 11025 N. Torrey Pines Road, Suite 120, La Jolla, California 92037, United States
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9
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Messina S, Bitto A, Vita GL, Aguennouz M, Irrera N, Licata N, Sframeli M, Bruschetta D, Minutoli L, Altavilla D, Vita G, Squadrito F. Modulation of neuronal nitric oxide synthase and apoptosis by the isoflavone genistein in Mdx mice. Biofactors 2015; 41:324-9. [PMID: 26332024 DOI: 10.1002/biof.1226] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 07/13/2015] [Accepted: 07/23/2015] [Indexed: 11/08/2022]
Abstract
Dystrophin lack in DMD causes neuronal nitric oxide synthase (nNOS) membrane delocalization which in turn promotes functional muscle ischemia, and exacerbates muscle injury. Apoptosis and the exhaustion of muscle regenerative capacity are implicated in Duchenne muscular dystrophy (DMD) pathogenesis and therefore are relevant therapeutic targets. Genistein has been reported to have pro-proliferative effects, promoting G1/S cell phase transition through the induction of cyclin D1, and anti-apoptotic properties. We previously showed that genistein could reduce muscle necrosis and enhance regeneration with an augmented number of myogenin-positive satellite cells and myonuclei, ameliorating muscle function in mdx mice. In this study we evaluated the underlying mechanisms of genistein effect on muscle specimens of mdx and wild type mice treated for five weeks with genistein (2 mg/kg/i.p. daily) or vehicle. Western blot analysis show that genistein increased cyclin D1 and nNOS expression; and showed an antiapoptotic effect, modulating the expression of BAX and Bcl-2. Our results suggest that this isoflavone might enhance the regenerative spurt in mdx mice muscle restoring nNOS, promoting G1/S phase transition in muscle cell, and inhibiting apoptosis. Further studies with longer time treatment or using different experimental approaches are needed to better investigate the underlying mechanisms of such results.
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Affiliation(s)
- Sonia Messina
- Department of Neurosciences, University of Messina, Messina, Italy
- Centro Clinico Nemo Sud, Messina, Italy
| | - Alessandra Bitto
- Department of Clinical and Experimental Medicine, Section of Pharmacology, University of Messina, Messina, Italy
| | - Gian Luca Vita
- Department of Neurosciences, University of Messina, Messina, Italy
- Centro Clinico Nemo Sud, Messina, Italy
| | | | - Natasha Irrera
- Department of Clinical and Experimental Medicine, Section of Pharmacology, University of Messina, Messina, Italy
| | - Norma Licata
- Department of Neurosciences, University of Messina, Messina, Italy
| | | | - Daniele Bruschetta
- Department of Biomorphology and Biotechnologies, University of Messina, Messina, Italy
| | - Letteria Minutoli
- Department of Clinical and Experimental Medicine, Section of Pharmacology, University of Messina, Messina, Italy
| | - Domenica Altavilla
- Department of Paediatric, Gynaecological, Microbiological and Biomedical Sciences, University of Messina, Messina, Italy
| | - Giuseppe Vita
- Department of Neurosciences, University of Messina, Messina, Italy
- Centro Clinico Nemo Sud, Messina, Italy
| | - Francesco Squadrito
- Department of Clinical and Experimental Medicine, Section of Pharmacology, University of Messina, Messina, Italy
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10
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Yuasa K, Aoki N, Hijikata T. JAZF1 promotes proliferation of C2C12 cells, but retards their myogenic differentiation through transcriptional repression of MEF2C and MRF4-Implications for the role of Jazf1 variants in oncogenesis and type 2 diabetes. Exp Cell Res 2015; 336:287-97. [PMID: 26101156 DOI: 10.1016/j.yexcr.2015.06.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 06/09/2015] [Accepted: 06/15/2015] [Indexed: 11/16/2022]
Abstract
Single-nucleotide polymorphisms associated with type 2 diabetes (T2D) have been identified in Jazf1, which is also involved in the oncogenesis of endometrial stromal tumors. To understand how Jazf1 variants confer a risk of tumorigenesis and T2D, we explored the functional roles of JAZF1 and searched for JAZF1 target genes in myogenic C2C12 cells. Consistent with an increase of Jazf1 transcripts during myoblast proliferation and their decrease during myogenic differentiation in regenerating skeletal muscle, JAZF1 overexpression promoted cell proliferation, whereas it retarded myogenic differentiation. Examination of myogenic genes revealed that JAZF1 overexpression transcriptionally repressed MEF2C and MRF4 and their downstream genes. AMP deaminase1 (AMPD1) was identified as a candidate for JAZF1 target by gene array analysis. However, promoter assays of Ampd1 demonstrated that mutation of the putative binding site for the TR4/JAZF1 complex did not alleviate the repressive effects of JAZF1 on promoter activity. Instead, JAZF1-mediated repression of Ampd1 occurred through the MEF2-binding site and E-box within the Ampd1 proximal regulatory elements. Consistently, MEF2C and MRF4 expression enhanced Ampd1 promoter activity. AMPD1 overexpression and JAZF1 downregulation impaired AMPK phosphorylation, while JAZF1 overexpression also reduced it. Collectively, these results suggest that aberrant JAZF1 expression contributes to the oncogenesis and T2D pathogenesis.
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Affiliation(s)
- Katsutoshi Yuasa
- Department of Anatomy and Cell Biology, Research Institute of Pharmaceutical Science, Faculty of Pharmacy, Musashino University, Nishitokyo, Tokyo 202-8585, Japan
| | - Natsumi Aoki
- Department of Anatomy and Cell Biology, Research Institute of Pharmaceutical Science, Faculty of Pharmacy, Musashino University, Nishitokyo, Tokyo 202-8585, Japan
| | - Takao Hijikata
- Department of Anatomy and Cell Biology, Research Institute of Pharmaceutical Science, Faculty of Pharmacy, Musashino University, Nishitokyo, Tokyo 202-8585, Japan.
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11
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Irazoqui AP, Heim NB, Boland RL, Buitrago CG. 1α,25 dihydroxi-vitamin D₃ modulates CDK4 and CDK6 expression and localization. Biochem Biophys Res Commun 2015; 459:137-42. [PMID: 25721671 DOI: 10.1016/j.bbrc.2015.02.083] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 02/14/2015] [Indexed: 12/18/2022]
Abstract
We recently reported that the vitamin D receptor (VDR) and p38 MAPK participate in pro-differentiation events triggered by 1α,25(OH)₂-vitamin D₃ [1,25D] in skeletal muscle cells. Specifically, our studies demonstrated that 1,25D promotes G0/G1 arrest of cells inducing cyclin D3 and cyclin dependent kinases inhibitors (CKIs) p21(Waf1/Cip1) and p27(Kip1) expression in a VDR and p38 MAPK dependent manner. In this work we present data indicating that cyclin-dependent kinases (CDKs) 4 and 6 also play a role in the mechanism by which 1,25D stimulates myogenesis. To investigate VDR involvement in hormone regulation of CDKs 4 and 6, we significantly reduced its expression by the use of a shRNA against mouse VDR, generating the skeletal muscle cell line C2C12-VDR. Investigation of changes in cellular cycle regulating proteins by immunoblotting showed that the VDR is involved in the 1,25D -induced CDKs 4 and 6 protein levels at 6 h of hormone treatment. CDK4 levels remains high during S phase peak and G0/G1 arrest while CDK6 expression decreases at 12 h and increases again al 24 h. The up-regulation of CDKs 4 and 6 by 1,25D (6 h) was abolished in C2C12 cells pre-treated with the ERK1/2 inhibitor, UO126. Moreover, CDKs 4 and 6 expression induced by the hormone nor was detected when α and β isoforms of p38 MAPK were inhibited by compound SB203580. Confocal images show that there is not co-localization between VDR and CDKs at 6 h of hormone treatment, however CDK4 and VDR co-localizates in nucleus after 12 h of 1,25D exposure. Of relevance, at this time 1,25D promotes CDK6 localization in a peri-nuclear ring. Our data demonstrate that the VDR, ERK1/2 and p38 MAPK are involved in the control of CDKs 4 and 6 by 1,25D in skeletal muscle cells sustaining the operation of a VDR and MAPKs -dependent mechanism in hormone modulation of myogenesis.
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Affiliation(s)
- Ana P Irazoqui
- INBIOSUR-CONICET y Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, San Juan 670, 8000 Bahía Blanca, Argentina
| | - Nadia B Heim
- INBIOSUR-CONICET y Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, San Juan 670, 8000 Bahía Blanca, Argentina
| | - Ricardo L Boland
- INBIOSUR-CONICET y Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, San Juan 670, 8000 Bahía Blanca, Argentina
| | - Claudia G Buitrago
- INBIOSUR-CONICET y Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, San Juan 670, 8000 Bahía Blanca, Argentina.
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12
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Irazoqui AP, Boland RL, Buitrago CG. Actions of 1,25(OH)2-vitamin D3 on the cellular cycle depend on VDR and p38 MAPK in skeletal muscle cells. J Mol Endocrinol 2014; 53:331-43. [PMID: 25316911 DOI: 10.1530/jme-14-0102] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Previously, we have reported that 1,25(OH)2-vitamin D3 (1,25D) activates p38 MAPK (p38) in a vitamin D receptor (VDR)-dependent manner in proliferative C2C12 myoblast cells. It was also demonstrated that 1,25D promotes muscle cell proliferation and differentiation. However, we did not study these hormone actions in depth. In this study we have investigated whether the VDR and p38 participate in the signaling mechanism triggered by 1,25D. In C2C12 cells, the VDR was knocked down by a shRNA, and p38 was specifically inhibited using SB-203580. Results from cell cycle studies indicated that hormone stimulation prompts a peak of S-phase followed by an arrest in the G0/G1-phase, events which were dependent on VDR and p38. Moreover, 1,25D increases the expression of cyclin D3 and the cyclin-dependent kinase inhibitors, p21(Waf1/Cip1) and p27(Kip1), while cyclin D1 protein levels did not change during G0/G1 arrest. In all these events, p38 and VDR were required. At the same time, a 1,25D-dependent acute increase in myogenin expression was observed, indicating that the G0/G1 arrest of cells is a pro-differentiative event. Immunocytochemical assays revealed co-localization of VDR and cyclin D3, promoted by 1,25D in a p38-dependent manner. When cyclin D3 expression was silenced, VDR and myogenin levels were downregulated, indicating that cyclin D3 was required for 1,25D-induced VDR expression and the concomitant entrance into the differentiation process. In conclusion, the VDR and p38 are involved in control of the cellular cycle by 1,25D in skeletal muscle cells, providing key information on the mechanisms underlying hormone regulation of myogenesis.
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Affiliation(s)
- Ana P Irazoqui
- INBIOSUR - CONICETDepartamento de Biología, Bioquímica and Farmacia, Universidad Nacional del Sur, San Juan 670, 8000 Bahía Blanca, Argentina
| | - Ricardo L Boland
- INBIOSUR - CONICETDepartamento de Biología, Bioquímica and Farmacia, Universidad Nacional del Sur, San Juan 670, 8000 Bahía Blanca, Argentina
| | - Claudia G Buitrago
- INBIOSUR - CONICETDepartamento de Biología, Bioquímica and Farmacia, Universidad Nacional del Sur, San Juan 670, 8000 Bahía Blanca, Argentina
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13
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Rajabi HN, Takahashi C, Ewen ME. Retinoblastoma protein and MyoD function together to effect the repression of Fra-1 and in turn cyclin D1 during terminal cell cycle arrest associated with myogenesis. J Biol Chem 2014; 289:23417-27. [PMID: 25006242 DOI: 10.1074/jbc.m113.532572] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The acquisition of skeletal muscle-specific function and terminal cell cycle arrest represent two important features of the myogenic differentiation program. These cellular processes are distinct and can be separated genetically. The lineage-specific transcription factor MyoD and the retinoblastoma protein pRb participate in both of these cellular events. Whether and how MyoD and pRb work together to effect terminal cell cycle arrest is uncertain. To address this question, we focused on cyclin D1, whose stable repression is required for terminal cell cycle arrest and execution of myogenesis. MyoD and pRb are both required for the repression of cyclin D1; their actions, however, were found not to be direct. Rather, they operate to regulate the immediate early gene Fra-1, a critical player in mitogen-dependent induction of cyclin D1. Two conserved MyoD-binding sites were identified in an intronic enhancer of Fra-1 and shown to be required for the stable repression of Fra-1 and, in turn, cyclin D1. Localization of MyoD alone to the intronic enhancer of Fra-1 in the absence of pRb was not sufficient to elicit a block to Fra-1 induction; pRb was also recruited to the intronic enhancer in a MyoD-dependent manner. These observations suggest that MyoD and pRb work together cooperatively at the level of the intronic enhancer of Fra-1 during terminal cell cycle arrest. This work reveals a previously unappreciated link between a lineage-specific transcription factor, a tumor suppressor, and a proto-oncogene in the control of an important facet of myogenic differentiation.
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Affiliation(s)
- Hasan N Rajabi
- From the Dana-Farber Cancer Institute, Boston, Massachusetts 02215
| | - Chiaki Takahashi
- From the Dana-Farber Cancer Institute, Boston, Massachusetts 02215, the Cancer Research Institute of Kanazawa University, 13-1 Takara-machi, Kanazawa 920-0934, Japan, and
| | - Mark E Ewen
- From the Dana-Farber Cancer Institute, Boston, Massachusetts 02215, the Molecular Oncology Research Institute, Tufts Medical Center, Boston, Massachusetts 02111
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14
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Narasimha AM, Kaulich M, Shapiro GS, Choi YJ, Sicinski P, Dowdy SF. Cyclin D activates the Rb tumor suppressor by mono-phosphorylation. eLife 2014; 3. [PMID: 24876129 PMCID: PMC4076869 DOI: 10.7554/elife.02872] [Citation(s) in RCA: 289] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Accepted: 05/22/2014] [Indexed: 11/30/2022] Open
Abstract
The widely accepted model of G1 cell cycle progression proposes that cyclin D:Cdk4/6 inactivates the Rb tumor suppressor during early G1 phase by progressive multi-phosphorylation, termed hypo-phosphorylation, to release E2F transcription factors. However, this model remains unproven biochemically and the biologically active form(s) of Rb remains unknown. In this study, we find that Rb is exclusively mono-phosphorylated in early G1 phase by cyclin D:Cdk4/6. Mono-phosphorylated Rb is composed of 14 independent isoforms that are all targeted by the E1a oncoprotein, but show preferential E2F binding patterns. At the late G1 Restriction Point, cyclin E:Cdk2 inactivates Rb by quantum hyper-phosphorylation. Cells undergoing a DNA damage response activate cyclin D:Cdk4/6 to generate mono-phosphorylated Rb that regulates global transcription, whereas cells undergoing differentiation utilize un-phosphorylated Rb. These observations fundamentally change our understanding of G1 cell cycle progression and show that mono-phosphorylated Rb, generated by cyclin D:Cdk4/6, is the only Rb isoform in early G1 phase. DOI:http://dx.doi.org/10.7554/eLife.02872.001 Cells go through a tightly controlled, multi-step procedure before they divide. This cell division program—the cell cycle—is necessary for preventing unrestrained cellular growth, which may lead to cancer. Proteins called cyclins control the progression through each of the phases of the cell cycle, with different cyclins working during different phases. During the G1 phase of the cell cycle, cells grow in size and produce the proteins that are required to copy DNA. Once a cell passes a checkpoint called the 'restriction point' at the end of the G1 phase, it is committed to dividing. It is therefore particularly important to keep events during G1 phase in check. The Retinoblastoma tumor suppresor protein (Rb) is a key player in regulating the G1 phase. Rb sequesters transcription factors that are essential for the cell cycle to progress. Previously, it was thought that a complex called cyclin D added more and more phosphates to the Rb protein during the G1 phase. This process predicted a slow release of transcription factors, which attach to DNA and start the process of DNA replication. While many studies have presented data that is consistent with this model, direct biochemical evidence of these events is lacking. Narasimha, Kaulich, Shapiro et al. now present biochemical analyses of Rb proteins that show—completely unexpectedly—that the cyclin D complex adds just one phosphate group to Rb during the G1 phase, although this group can be added to one of fourteen different sites. The resulting 'mono-phosphorylated' Rb varieties can each sequester different transcription factors and stop them working. At the restriction point, many more phosphate groups are then rapidly added, and the Rb protein is inactivated by a different cyclin. This cyclin—called Cyclin E—then drives cells into the next phase of the cell cycle. Establishing how cyclin E is activated is a priority for future research. DOI:http://dx.doi.org/10.7554/eLife.02872.002
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Affiliation(s)
- Anil M Narasimha
- Department of Cellular and Molecular Medicine, University of California, San Diego School of Medicine, La Jolla, United States
| | - Manuel Kaulich
- Department of Cellular and Molecular Medicine, University of California, San Diego School of Medicine, La Jolla, United States
| | - Gary S Shapiro
- Department of Cellular and Molecular Medicine, University of California, San Diego School of Medicine, La Jolla, United States
| | - Yoon J Choi
- Department of Genetics, Harvard Medical School, Boston, United States
| | - Piotr Sicinski
- Department of Genetics, Harvard Medical School, Boston, United States
| | - Steven F Dowdy
- Department of Cellular and Molecular Medicine, University of California, San Diego School of Medicine, La Jolla, United States
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15
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p19Ink4d is a tumor suppressor and controls pituitary anterior lobe cell proliferation. Mol Cell Biol 2014; 34:2121-34. [PMID: 24687853 DOI: 10.1128/mcb.01363-13] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pituitary tumors develop in about one-quarter of the population, and most arise from the anterior lobe (AL). The pituitary gland is particularly sensitive to genetic alteration of genes involved in the cyclin-dependent kinase (CDK) inhibitor (CKI)-CDK-retinoblastoma protein (Rb) pathway. Mice heterozygous for the Rb mutation develop pituitary tumors, with about 20% arising from the AL. Perplexingly, none of the CKI-deficient mice reported thus far develop pituitary AL tumors. In this study, we show that deletion of p19(Ink4d) (p19), a CKI gene, in mice results in spontaneous development of tumors in multiple organs and tissues. Specifically, more than one-half of the mutant mice developed pituitary hyperplasia or tumors predominantly in the AL. Tumor development is associated with increased cell proliferation and enhanced activity of Cdk4 and Cdk6 and phosphorylation of Rb protein. Though Cdk4 is indispensable for postnatal pituitary cell proliferation, it is not required for the hyperproliferative pituitary phenotype caused by p19 loss. Loss of p19 phosphorylates Rb in Cdk4(-/-) pituitary AL cells and mouse embryonic fibroblasts (MEFs) and rescues their proliferation defects, at least partially, through the activation of Cdk6. These results provide the first genetic evidence that p19 is a tumor suppressor and the major CKI gene that controls pituitary AL cell proliferation.
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16
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Doherty JR, Nilsson LM, Kuliyev E, Zhu H, Matthew R, Cleveland JL, Mead PE, Roussel MF. Embryonic Expression and Function of the Xenopus Ink4d Cyclin D-Dependent Kinase Inhibitor. ACTA ACUST UNITED AC 2014; 3. [PMID: 25309971 PMCID: PMC4192657 DOI: 10.4172/2168-9296.1000133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Here we report the cloning and functional characterization of the cyclin D-dependent kinase 4 and 6 (Cdk4/6) inhibitory protein Cdkn2d/p19Ink4d of Xenopuslaevis (Xl-Ink4d). Xl-Ink4d is the only Ink4 family gene highly expressed during Xenopus development and its transcripts were detected maternally and during neurulation. The Xl-Ink4d protein has 63% identity to mouse and human Cdkn2d/p19Ink4d and its function as a negative regulator of cell cycle traverse is evolutionary conserved. Indeed, Xl-lnk4d can functionally substitute for mouse Cdkn2d in binding to mouse Cdk4 and inhibiting cyclin-D1-dependent CDK4 kinase activity. Further, enforced expression of Xl-lnk4d arrests mouse fibroblasts in the G1 phase of the cell cycle. These findings indicate that CDKN2d/p19Ink4d is conserved through vertebrate evolution and suggest Xl-lnk4d may contribute to the development of Xenopuslaevis.
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Affiliation(s)
- Joanne R Doherty
- Department of Pathology, St. Jude Children's Research Hospital, TN, USA
| | - Lisa M Nilsson
- Department of Biochemistry St. Jude Children's Research Hospital, TN, USA
| | - Emin Kuliyev
- Department of Tumor Cell Biology, St. Jude Children's Research Hospital, TN, USA
| | - Haiqing Zhu
- Department of Cancer Biology, The Scripps Research Institute, Scripps Florida, FL, USA
| | - Rose Matthew
- Sahlgrenska Cancer Center, University of Gothenburg, Gothenburg, Sweden
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17
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Irazoqui AP, Boland RL, Buitrago CG. WITHDRAWN: VDR involvement in 1a,25-dihydroxyvitamin D3-action on cellular cycle in C2C12 skeletal muscle cells. J Steroid Biochem Mol Biol 2013:S0960-0760(13)00214-8. [PMID: 24184698 DOI: 10.1016/j.jsbmb.2013.10.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 10/18/2013] [Accepted: 10/23/2013] [Indexed: 11/30/2022]
Abstract
This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.
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Affiliation(s)
- Ana P Irazoqui
- Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, 8000 Bahía Blanca, Argentina
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18
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Al-Tahan A, Sarkis O, Harajly M, Baghdadi OK, Zibara K, Boulos F, Dighe D, Kregel S, Bazarbachi A, El-Sabban M, Skapek SX, Saab R. Retinoic acid fails to induce cell cycle arrest with myogenic differentiation in rhabdomyosarcoma. Pediatr Blood Cancer 2012; 58:877-84. [PMID: 21755593 DOI: 10.1002/pbc.23246] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Accepted: 05/26/2011] [Indexed: 12/16/2022]
Abstract
BACKGROUND Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children. Current treatment strategies do not cure most children with recurrent or high-risk disease, underlying the need for novel therapeutic approaches. Retinoic acid has been shown to induce differentiation in a variety of cells including skeletal myoblasts and neuroblasts. In the setting of minimal residual disease, retinoic acid improves survival in neuroblastoma, another poorly differentiated childhood tumor. Whether such an approach is useful for rhabdomyosarcoma has not yet been investigated. Several in vitro studies have demonstrated an appreciable effect of retinoic acid on human RMS cellular proliferation and differentiation. PROCEDURE We assessed the efficacy of ATRA on rhabdomyosarcoma, in vitro and in vivo, using cell lines and xenografts. RESULTS ATRA slowed RMS cell proliferation, and promoted a more differentiated myogenic phenotype in both alveolar and embryonal RMS cell lines. Treatment of cultured murine myoblasts with retinoids increased Myogenin expression, but did not induce cell cycle arrest. Despite the favorable in vitro effects, ATRA failed to delay relapse of minimal residual disease using human RMS xenografts in immuno-suppressed NOD-SCID (NSG) mice. Interestingly, tumors that recurred after ATRA treatment showed evidence of enhanced muscle differentiation. CONCLUSION Our results indicate that ATRA could increase the expression of some genes associated with muscle differentiation in rhabdomyosarcoma cells, but there was no benefit of single-agent therapy in an MRD model, likely because cell cycle arrest was uncoupled from the pro-differentiation effects of retinoids.
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Affiliation(s)
- Alaa Al-Tahan
- Department of Pediatrics, American University of Beirut, Beirut, Lebanon
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19
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Mancinelli R, Pietrangelo T, Burnstock G, Fanò G, Fulle S. Transcriptional profile of GTP-mediated differentiation of C2C12 skeletal muscle cells. Purinergic Signal 2011; 8:207-21. [PMID: 22127439 DOI: 10.1007/s11302-011-9266-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Accepted: 10/03/2011] [Indexed: 02/01/2023] Open
Abstract
Several purine receptors have been localised on skeletal muscle membranes. Previous data support the hypothesis that extracellular guanosine 5'-triphosphate (GTP) is an important regulatory factor in the development and function of muscle tissue. We have previously described specific extracellular binding sites for GTP on the plasma membrane of mouse skeletal muscle (C2C12) cells. Extracellular GTP induces an increase in intracellular Ca(2+) concentrations that results in membrane hyperpolarisation through Ca(2+)-activated K(+) channels, as has been demonstrated by patch-clamp experiments. This GTP-evoked increase in intracellular Ca(2+) is due to release of Ca(2+) from intracellular inositol-1,4,5-trisphosphate-sensitive stores. This enhances the expression of the myosin heavy chain in these C2C12 myoblasts and commits them to fuse into multinucleated myotubes, probably via a phosphoinositide-3-kinase-dependent signal-transduction mechanism. To define the signalling of extracellular GTP as an enhancer or modulator of myogenesis, we investigated whether the gene-expression profile of differentiated C2C12 cells (4 and 24 h in culture) is affected by extracellular GTP. To investigate the nuclear activity and target genes modulated by GTP, transcriptional profile analysis and real-time PCR were used. We demonstrate that in the early stages of differentiation, GTP up-regulates genes involved in different pathways associated with myogenic processes, including cytoskeleton structure, the respiratory chain, myogenesis, chromatin reorganisation, cell adhesion, and the Jak/Stat pathway, and down-regulates the mitogen-activated protein kinase pathway. GTP also increases the expression of three genes involved in myogenesis, Pp3ca, Gsk3b, and Pax7. Our data suggests that in the myogenic C2C12 cell line, extracellular GTP acts as a differentiative factor in the induction and sustaining of myogenesis.
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Affiliation(s)
- Rosa Mancinelli
- Department of Neuroscience and Imaging, University G. d'Annunzio Chieti-Pescara, Chieti, Italy.
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20
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Gagrica S, Brookes S, Anderton E, Rowe J, Peters G. Contrasting behavior of the p18INK4c and p16INK4a tumor suppressors in both replicative and oncogene-induced senescence. Cancer Res 2011; 72:165-75. [PMID: 22080569 DOI: 10.1158/0008-5472.can-11-2552] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The cyclin-dependent kinase (CDK) inhibitors, p18(INK4c) and p16(INK4a), both have the credentials of tumor suppressors in human cancers and mouse models. For p16(INK4a), the underlying rationale is its role in senescence, but the selective force for inactivation of p18(INK4c) in incipient cancer cells is less clear. Here, we show that in human fibroblasts undergoing replicative or oncogene-induced senescence, there is a marked decline in the levels of p18(INK4c) protein and RNA, which mirrors the accumulation of p16(INK4a). Downregulation of INK4c is not dependent on p16(INK4a), and RAS can promote the loss of INK4c without cell-cycle arrest. Downregulation of p18(INK4c) correlates with reduced expression of menin and E2F1 but is unaffected by acute cell-cycle arrest or inactivation of the retinoblastoma protein (pRb). Collectively, our data question the idea that p18(INK4c) acts as a backup for loss of p16(INK4a) and suggest that the apparent activation of p18(INK4c) in some settings represents delayed senescence rather than increased expression. We propose that the contrasting behavior of the two very similar INK4 proteins could reflect their respective roles in senescence versus differentiation.
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Affiliation(s)
- Sladjana Gagrica
- Molecular Oncology Laboratory, CRUK London Research Institute, London, United Kingdom
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21
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Broxmeyer HE, Franklin DS, Cooper S, Hangoc G, Mantel C. Cyclin dependent kinase inhibitors differentially modulate synergistic cytokine responsiveness of hematopoietic progenitor cells. Stem Cells Dev 2011; 21:1597-603. [PMID: 21936707 DOI: 10.1089/scd.2011.0476] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Cyclin dependent kinase inhibitors (CDKIs) influence proliferation of hematopoietic progenitor cells (HPCs), but little is known of how they influence proliferative responsiveness of HPCs to colony stimulating factors (CSFs), alone and in combination with other hematopoietically active factors, such as the potent co-stimulating cytokine stem cell factor (SCF), or inhibition by myelosuppressive chemokines. Using mice with deletions in p18(INK4c), p21(CIP1/WAF1), or p27(KIP1) genes, and in mice with double gene deletions for either p18/p21 or p18/p27, we determined effects of absence of these CDKIs and their interactions on functional HPC numbers in vivo, and HPC proliferative responsiveness in vitro. There is a decrease in bone marrow HPC proliferation in p18(-/-) mice commensurate with decreased numbers of HPC, suggesting a positive role for p18 on HPC in vivo, similar to that for p21. These positive effects of p18 dominate negative effects of p27 gene deletion. Moreover, the CDKIs differentially regulate responsiveness of granulocyte macrophage (GM) progenitors to synergistic cell proliferation in response to GM-CSF plus SCF, which is considered important for normal hematopoiesis. Responsiveness of HPCs to inhibition by myelosuppressive chemokines is directly related to the capacity of HPCs to respond to synergistic stimulation, and their cell cycle status. P18(INK4c) gene deletion rescued the loss of chemokine suppression of synergistic proliferation due to deletion of p21(CIP1/WAF1). These findings underscore the complex interplay of cell cycle regulators in HPC, and demonstrate that loss of one can sometimes be compensated by loss of another CDKI in both, a pro- or anti-proliferative context.
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Affiliation(s)
- Hal E Broxmeyer
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana 46202-5181, USA.
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22
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The myogenic kinome: protein kinases critical to mammalian skeletal myogenesis. Skelet Muscle 2011; 1:29. [PMID: 21902831 PMCID: PMC3180440 DOI: 10.1186/2044-5040-1-29] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Accepted: 09/08/2011] [Indexed: 12/13/2022] Open
Abstract
Myogenesis is a complex and tightly regulated process, the end result of which is the formation of a multinucleated myofibre with contractile capability. Typically, this process is described as being regulated by a coordinated transcriptional hierarchy. However, like any cellular process, myogenesis is also controlled by members of the protein kinase family, which transmit and execute signals initiated by promyogenic stimuli. In this review, we describe the various kinases involved in mammalian skeletal myogenesis: which step of myogenesis a particular kinase regulates, how it is activated (if known) and what its downstream effects are. We present a scheme of protein kinase activity, similar to that which exists for the myogenic transcription factors, to better clarify the complex signalling that underlies muscle development.
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23
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Saab R, Spunt SL, Skapek SX. Myogenesis and rhabdomyosarcoma the Jekyll and Hyde of skeletal muscle. Curr Top Dev Biol 2011; 94:197-234. [PMID: 21295688 DOI: 10.1016/b978-0-12-380916-2.00007-3] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Rhabdomyosarcoma, a neoplasm composed of skeletal myoblast-like cells, represents the most common soft tissue sarcoma in children. The application of intensive chemotherapeutics and refined surgical and radiation therapy approaches have improved survival for children with localized disease over the past 3 decades; however, these approaches have not improved the dismal outcome for children with metastatic and recurrent rhabdomyosarcoma. Elegant studies have defined the molecular mechanisms driving skeletal muscle lineage commitment and differentiation, and the machinery that couples differentiation with irreversible cell proliferation arrest. Further, detailed molecular analyses indicate that rhabdomyosarcoma cells have lost the capacity to fully differentiate when challenged to do so in experimental models. We review the intersection of normal skeletal muscle developmental biology and the molecular genetic defects in rhabdomyosarcoma with the underlying premise that understanding how the differentiation process has gone awry will lead to new treatment strategies aimed at promoting myogenic differentiation and concomitant cell cycle arrest.
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Affiliation(s)
- Raya Saab
- Children's Cancer Center of Lebanon, Department of Pediatrics, American University of Beirut, Beirut, Lebanon
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24
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Kulkarni MV, Franklin DS. N-Myc is a downstream target of RET signaling and is required for transcriptional regulation of p18(Ink4c) by the transforming mutant RET(C634R). Mol Oncol 2010; 5:24-35. [PMID: 21112821 DOI: 10.1016/j.molonc.2010.10.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Revised: 10/11/2010] [Accepted: 10/12/2010] [Indexed: 12/17/2022] Open
Abstract
Inherited activating mutations in RET predispose humans to Multiple Endocrine Neoplasia type-2 (MEN2). The MEN2A-specific mutation RET(C634R), RET2A, has been shown to simultaneously downregulate the CDKIs p18 and p27, and upregulate cyclin D1. Importantly, the loss of p18 is necessary and sufficient for RET2A-mediated hyperproliferation. The loss of N-Myc in mice results in embryonic lethality due to a lack of neuronal progenitor cells that fail to proliferate, correlate with accumulation of p18 and p27. Therefore, N-Myc may regulate expression of both CDKIs. Also, N-Myc is expressed predominantly in neuroendocrine cells that give rise to the primary cell types affected in MEN2A. Together these studies suggest that N-Myc is a downstream target of RET2A signaling that prevents accumulation of p18 and/or p27. We report that MAPK activation by RET2A leads to a transient induction of N-Myc mRNA and protein levels, and that N-Myc induction is required to maintain low p18 and p27 levels. Induced N-Myc levels correlate with increased binding of N-Myc to an initiator consensus binding site in the p18 promoter, and this binding is essential for RET2A-mediated transcriptional regulation of p18. Finally, loss of N-Myc induction prevents RET2A-mediated hyperproliferation. Our results demonstrate for the first time that N-Myc is a downstream target of RET2A signaling, and propose that induction of N-Myc by RET2A is a key step leading to lower p18 levels during MEN2A tumorigenesis.
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Affiliation(s)
- Mandar V Kulkarni
- Department of Biological Sciences, Purdue University, 915 W. State Street West Lafayette, IN 47907, USA.
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25
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Yen YP, Tsai KS, Chen YW, Huang CF, Yang RS, Liu SH. Arsenic inhibits myogenic differentiation and muscle regeneration. ENVIRONMENTAL HEALTH PERSPECTIVES 2010; 118:949-56. [PMID: 20299303 PMCID: PMC2920914 DOI: 10.1289/ehp.0901525] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Accepted: 03/18/2010] [Indexed: 05/08/2023]
Abstract
BACKGROUND The incidence of low birth weights is increased in offspring of women who are exposed to high concentrations of arsenic in drinking water compared with other women. We hypothesized that effects of arsenic on birth weight may be related to effects on myogenic differentiation. OBJECTIVE We investigated the effects of arsenic trioxide (As2O3) on the myogenic differentiation of myoblasts in vitro and muscle regeneration in vivo. METHODS C2C12 myoblasts and primary mouse and human myoblasts were cultured in differentiation media with or without As2O3 (0.1-0.5 microM) for 4 days. Myogenic differentiation was assessed by myogenin and myosin heavy chain expression and multinucleated myotube formation in vitro; skeletal muscle regeneration was tested using an in vivo mouse model with experimental glycerol myopathy. RESULTS A submicromolar concentration of As2O3 dose-dependently inhibited myogenic differentiation without apparent effects on cell viability. As2O3 significantly and dose-dependently decreased phosphorylation of Akt and p70s6k proteins during myogenic differentiation. As2O3-induced inhibition in myotube formation and muscle-specific protein expression was reversed by transfection with the constitutively active form of Akt. Sections of soleus muscles stained with hematoxylin and eosin showed typical changes of injury and regeneration after local glycerol injection in mice. Regeneration of glycerol-injured soleus muscles, myogenin expression, and Akt phosphorylation were suppressed in muscles isolated from As2O3-treated mice compared with untreated mice. CONCLUSION Our results suggest that As2O3 inhibits myogenic differentiation by inhibiting Akt-regulated signaling.
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Affiliation(s)
| | - Keh-Sung Tsai
- Department of Laboratory Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ya-Wen Chen
- Department of Physiology and
- Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan
| | - Chun-Fa Huang
- Graduate Institute of Chinese Medical Science, School of Chinese Medicine, China Medical University, Taichung, Taiwan
| | | | - Shing-Hwa Liu
- Institute of Toxicology and
- Department of Urology, College of Medicine and Hospital, National Taiwan University, Taipei, Taiwan
- Address correspondence to S.H. Liu, Institute of Toxicology, College of Medicine, National Taiwan University, No. 1, Section 1, Jen-Ai Rd., Taipei, 10051, Taiwan. Telephone: 886-2-23123456, ext. 88605. Fax: 886-2-23410217. E-mail:
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26
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Li L, Zhang G, Zhang Y, Tan J, Huang H, Huang B, Lu J. Sodium butyrate-induced upregulation of p18( INK4C ) gene affects K562 cell G (0)/G (1) arrest and differentiation. Mol Cell Biochem 2008; 319:9-15. [PMID: 18642058 DOI: 10.1007/s11010-008-9870-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Accepted: 07/03/2008] [Indexed: 01/06/2023]
Abstract
Histone deacetylase inhibitor sodium butyrate (NaBu) can induce G(0)/G(1) arrest and erythroid differentiation in K562 cells, but the molecular mechanisms underlying this process are unclear. Here we show that both p18( INK4C ) mRNA and protein levels were upregulated during K562 cell erythroid differentiation induced by NaBu. Moreover, the NaBu activation of p18( INK4C ) was dependent on the integrity of Sp1 clusters in the promoter. NaBu caused hyperacetylation of histones H3 and H4 on endogenous p18( INK4C ) promoter and enhanced binding of transcription factor Sp1 in vivo. Also, overexpression of p18( INK4C ) in K562 cells resulted in G(0)/G(1) arrest and partial erythroid differentiation. Our results suggested that NaBu-mediated p18( INK4C ) regulation played a role in cell cycle arrest and erythroid differentiation in K562 cells.
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Affiliation(s)
- Lin Li
- Institute of Genetics and Cytology, Northeast Normal University, Changchun, China
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Buchold GM, Magyar PL, O'Brien DA. Mice lacking cyclin-dependent kinase inhibitor p19Ink4d show strain-specific effects on male reproduction. Mol Reprod Dev 2007; 74:1008-20. [PMID: 17393423 DOI: 10.1002/mrd.20715] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
p19(Ink4d) is a member of the INK4 family of cyclin-dependent kinase inhibitors, which are important negative regulators of the G1-phase cyclin-dependent kinases CDK4 and CDK6. On a mixed C57BL/6 x 129P2/OlaHsd background, mice deficient for p19(Ink4d) exhibited defects in male reproductive function including testicular atrophy, alteration in serum follicle stimulating hormone, qualitative increase in germ cell apoptosis, and delayed kinetics of meiotic prophase markers (Zindy et al., 2001. Mol Cell Biol 21:3244-3255; Zindy et al., 2000. Mol Cell Biol 20:372-378). In this study, a quantitative assessment of these aspects of reproductive capacity demonstrated relatively mild deficits in p19(Ink4d-/-) males compared to controls. These effects did not dramatically worsen in older males although some seminiferous tubule defects were observed. Following marker-assisted backcrossing into the C57BL/6 background, p19(Ink4d-/-) males did not display defects in testis weights, sperm numbers, serum FSH, germ cell apoptosis, or kinetics of selected meiotic prophase markers. These studies indicate that a reduction in Ink4 family function by the loss of p19(Ink4d) is sufficient to induce mild reproductive defects in male mice with a mixed genetic background, but not in the C57BL/6 genetic background.
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Affiliation(s)
- Gregory M Buchold
- Curriculum in Genetics and Molecular Biology, The University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
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28
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Buchold GM, Magyar PL, Arumugam R, Lee MM, O'Brien DA. p19Ink4d and p18Ink4c cyclin-dependent kinase inhibitors in the male reproductive axis. Mol Reprod Dev 2007; 74:997-1007. [PMID: 17342741 DOI: 10.1002/mrd.20716] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The loss of the cyclin-dependent kinase inhibitors (CKIs) p18(Ink4c) and p19(Ink4d) leads to male reproductive defects (Franklin et al., 1998. Genes Dev 12: 2899-2911; Zindy et al., 2000. Mol Cell Biol 20: 372-378; Zindy et al., 2001. Mol Cell Biol 21: 3244-3255). In order to assess whether these inhibitors directly or indirectly affect male germ cell differentiation, we examined the expression of p18(Ink4c) and p19(Ink4d) in spermatogenic and supporting cells in the testis and in pituitary gonadotropes. Both p18(Ink4c) and p19(Ink4d) are most abundant in the testis after 18 days of age and are expressed in purified populations of spermatogenic and testicular somatic cells. Different p18(Ink4c) mRNAs are expressed in isolated spermatogenic and Leydig cells. Spermatogenic cells also express a novel p19(Ink4d) transcript that is distinct from the smaller transcript expressed in Sertoli cells, Leydig cells and in other tissues. Immunohistochemistry detected significant levels of p19(Ink4d) in preleptotene spermatocytes, pachytene spermatocytes, condensing spermatids, and Sertoli cells. Immunoprecipitation-Western analysis detected both CKI proteins in isolated pachytene spermatocytes and round spermatids. CDK4/6-CKI complexes were detected in germ cells by co-immunoprecipitation, although the composition differed by cell type. p19(Ink4d) was also identified in FSH+ gonadotrophs, suggesting that this CKI may be independently required in the pituitary. Possible cell autonomous and paracrine mechanisms for the spermatogenic defects in mice lacking p18(Ink4c) or p19(Ink4d) are supported by expression of these CKIs in spermatogenic cells and in somatic cells of the testis and pituitary.
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Affiliation(s)
- Gregory M Buchold
- Curriculum in Genetics and Molecular Biology, The University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
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29
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Joshi PP, Kulkarni MV, Yu BK, Smith KR, Norton DL, van Veelen W, Höppener JWM, Franklin DS. Simultaneous downregulation of CDK inhibitors p18(Ink4c) and p27(Kip1) is required for MEN2A-RET-mediated mitogenesis. Oncogene 2006; 26:554-70. [PMID: 16953232 DOI: 10.1038/sj.onc.1209811] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Multiple endocrine neoplasia type 2A (MEN2A) is predisposed by mutations in the RET proto-oncogene. Low expression of the cyclin-dependent kinase inhibitor (CDKI) p27(Kip1) is present in thyroid tumors, and recent evidence demonstrates p27 downregulation by the active RET mutant, RET/PTC1, found in papillary thyroid carcinoma. This implicates decreased p27 activity as an important event during thyroid tumorigenesis. However, p27(-/-) mice develop MEN-like tumors only in combination with loss of another CDKI, p18(Ink4c). This suggests that p18 and p27 functionally collaborate in suppression of tumorigenesis, that loss of both is critical in the development of MEN tumors and that both p18 and p27 are regulated by RET. We report that induction of the constitutively active MEN2A-specific RET mutant, RET2A(C634R), correlates with reduced p18/p27, and elevated cyclin D protein levels, leading to increased CDK activity, increased pRb phosphorylation and proliferation under growth arrest conditions. Mechanistically, RET2A represses p18/p27 mRNA levels while elevating cyclin D1 mRNA levels. RET2A expression also correlates with decreased p27 protein stability. RET2A-mediated regulation of p18 and p27, but not of cyclins D1 and D2, requires functional mitogen-activated protein kinase signaling. Additionally, RET2A-dependent p18 repression is required and sufficient to increase cell proliferation. Perhaps most significantly, MEN2A adrenal tumors also display these changes in cell cycle expression profile, demonstrating the biological relevance of our cell culture studies. Our results demonstrate for the first time that RET2A regulates p18, and suggest that loss of not only p27 but also of p18 expression is a key step in MEN tumorigenesis.
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Affiliation(s)
- P P Joshi
- Department of Biological Sciences, Purdue Cancer Center, Purdue University, West Lafayette, IN, USA
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30
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Zacharek SJ, Xiong Y, Shumway SD. Negative regulation of TSC1-TSC2 by mammalian D-type cyclins. Cancer Res 2006; 65:11354-60. [PMID: 16357142 DOI: 10.1158/0008-5472.can-05-2236] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The metazoan cell cycle is driven by the timely and composite activities of cyclin-dependent kinases (CDKs). Among these, cyclin D- and cyclin E-dependent kinases phosphorylate the pRb family proteins during G(1) phase of the cell cycle and thereby advance cells beyond the restriction point. Increasing evidence suggests that cyclin D-dependent kinases might affect events other than Rb pathway-mediated entry into S phase, such as accumulation of cell mass. However, little is known about cyclin D activity toward Rb-independent pathway(s) or non-pRb substrates. In this article, we show that the tumor suppressor TSC2 is a cyclin D binding protein. Coexpression of cyclin D1-CDK4/6 in cultured cells leads to increased phosphorylation and decreased detection of both TSC2 and TSC1, and promotes the phosphorylation of the mTOR substrates, 4E-BP1 and S6K1, two key effectors of cell growth that are negatively regulated by the TSC1-TSC2 complex. At the cellular level, ectopic expression of cyclin D1 restores the cell size decrease caused by TSC1-TSC2 expression. Intriguingly, down-regulation of TSC proteins was also observed by the expression of a mutant cyclin D1 that is unable to bind to CDK4/6, or by the coexpression of cyclin D1 with either an INK4 inhibitor or with catalytically inactive CDK6, indicating that cyclin D may regulate TSC1-TSC2 independently of CDK4/6. Together, these observations suggest that mammalian D-type cyclins participate in cell growth control through negative regulation of TSC1-TSC2 function.
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Affiliation(s)
- Sima J Zacharek
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, 27599, USA
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31
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Hu J, Xiong Y. An evolutionarily conserved function of proliferating cell nuclear antigen for Cdt1 degradation by the Cul4-Ddb1 ubiquitin ligase in response to DNA damage. J Biol Chem 2006; 281:3753-6. [PMID: 16407242 DOI: 10.1074/jbc.c500464200] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The DNA replication licensing factor Cdt1 is degraded by the ubiquitin-proteasome pathway during S phase of the cell cycle, to ensure one round of DNA replication during each cell division and in response to DNA damage to halt DNA replication. Constitutive expression of Cdt1 causes DNA re-replication and is associated with the development of a subset of human non-small cell-lung carcinomas. In mammalian cells, DNA damage-induced Cdt1 degradation is catalyzed by the Cul4-Ddb1-Roc1 E3 ubiquitin ligase. We report here that overexpression of the proliferating cell nuclear antigen (PCNA) inhibitory domain from the CDK inhibitors p21 and p57, but not the CDK-cyclin inhibitory domain, blocked Cdt1 degradation in cultured mammalian cells after UV irradiation. In vivo soluble Cdt1 and PCNA co-elute by gel filtration and associate with each other physically. Silencing PCNA in cultured mammalian cells or repression of pcn1 expression in fission yeast blocked Cdt1 degradation in response to DNA damage. Unexpectedly, deletion of Ddb1 in fission yeast cells also accumulated Cdt1 in the absence of DNA damage. We suggest that the Cul4-Ddb1 ligase evolved to ubiquitinate Cdt1 during normal cell growth as well as in response to DNA damage and a separate E3 ligase, possibly SCF(Skp2), evolved to either share or take over the function of Cdt1 ubiquitination during normal cell growth and that PCNA is involved in mediating Cdt1 degradation by the Cul4-Ddb1 ligase in response to DNA damage.
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Affiliation(s)
- Jian Hu
- Department of Biochemistry and Biophysics, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, 27516-7295, USA
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32
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Ghanem L, Steinman R. A proapoptotic function of p21 in differentiating granulocytes. Leuk Res 2005; 29:1315-23. [PMID: 15893818 DOI: 10.1016/j.leukres.2005.03.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2005] [Revised: 03/25/2005] [Accepted: 03/29/2005] [Indexed: 11/19/2022]
Abstract
p21(waf 1/cip 1) (p21), best known for its ability to regulate the cell cycle, has been noted also to exert cell cycle-independent effects on apoptosis and differentiation. Inhibition of apoptosis by p21 has been reported in hematopoietic models, particularly in monocytes exposed to apoptogenic agents. The effect of p21 on survival has not hitherto been analyzed during the myeloblast to granulocyte transition. Using 32 Dc l3 murine myeloblasts, a cell line that proliferates in IL-3 and differentiates in G-CSF, we studied the effects of forced expression of p21 on cell survival. We hypothesized that exogenous p21 would suppress the modest levels of cell death associated with G-CSF-mediated differentiation of 32 Dc l3 cells. Contrary to expectations, we found that exogenous p21 enhanced apoptosis of cells removed from IL-3. The p21 overexpression led to decreased cell growth, caspase-3 activation and annexin positivity. These effects occurred only in the presence of G-CSF. These findings suggest that p21 is proapoptotic in granulopoiesis, and that this effect is masked by IL-3-mediated survival signals. Our results also indicate there are distinct and opposing effects of p21 on monocytic and granulocytic survival. Aberrantly high levels of p21 may contribute to disease processes involving excessive apoptosis of granulocyte precursors.
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Affiliation(s)
- Louis Ghanem
- University of Pittsburgh School of Medicine, Department of Medicine, Hillman Cancer Center, Lab 2.18, 5117 Center Avenue, Pittsburgh, PA 15213, USA
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33
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Lu G, Seta KA, Millhorn DE. Novel role for cyclin-dependent kinase 2 in neuregulin-induced acetylcholine receptor epsilon subunit expression in differentiated myotubes. J Biol Chem 2005; 280:21731-8. [PMID: 15824106 DOI: 10.1074/jbc.m412498200] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Cyclin-dependent kinases (CDKs) are a family of evolutionarily conserved serine/threonine kinases. CDK2 acts as a checkpoint for the G(1)/S transition in the cell cycle. Despite a down-regulation of CDK2 activity in postmitotic cells, many cell types, including muscle cells, maintain abundant levels of CDK2 protein. This led us to hypothesize that CDK2 may have a function in postmitotic cells. We show here for the first time that CDK2 can be activated by neuregulin (NRG) in differentiated C2C12 myotubes. In addition, this activity is required for expression of the acetylcholine receptor (AChR) epsilon subunit. The switch from the fetal AChRgamma subunit to the adult-type AChRepsilon is required for synapse maturation and the neuromuscular junction. Inhibition of CDK2 activity with either the specific CDK2 inhibitory peptide Tat-LFG or by RNA interference abolished neuregulin-induced AChRepsilon expression. Neuregulin-induced activation of CDK2 also depended on the ErbB receptor, MAPK, and PI3K, all of which have previously been shown to be required for AChRepsilon expression. Neuregulin regulated CDK2 activity through coordinating phosphorylation of CDK2 on Thr-160, accumulation of CDK2 in the nucleus, and down-regulation of the CDK2 inhibitory protein p27 in the nucleus. In addition, we also observed a novel mechanism of regulation of CDK2 activity by a low molecular weight variant of cyclin E in response to NRG. These findings establish CDK2 as an intermediate molecule that integrates NRG-activated signals from both the MAPK and PI3K pathways to AChRepsilon expression and reveal an undiscovered physiological role for CDK2 in postmitotic cells.
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Affiliation(s)
- Gang Lu
- Department of Genome Science, Genome Research Institute, University of Cincinnati, 2180 E. Galbraith Road, Cincinnati, OH 45237, USA
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34
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Kumar A, Murphy R, Robinson P, Wei L, Boriek AM. Cyclic mechanical strain inhibits skeletal myogenesis through activation of focal adhesion kinase, Rac-1 GTPase, and NF-kappaB transcription factor. FASEB J 2005; 18:1524-35. [PMID: 15466361 DOI: 10.1096/fj.04-2414com] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Myogenesis is a multistep developmental program that generates and regenerates skeletal muscles. Several extracellular factors have been identified that participate in the regulation of myogenesis. Although skeletal muscles are always subjected to mechanical stress in vivo, the role of mechanical forces in the regulation of myogenesis remains unknown. We have investigated the molecular mechanisms by which cyclic mechanical strain modulates myogenesis. Application of cyclic mechanical strain using the computer-controlled Flexcell Strain Unit increased the proliferation of C2C12 cells and inhibited their differentiation into myotubes. Cyclic strain increased the activity of cyclin-dependent kinase 2 (cdk2) and the cellular level of cyclin A, and inhibited the expression of myosin heavy chain and formation of myotubes in C2C12 cultures. The activity of nuclear factor-kappa B (NF-kappaB) transcription factor and the expression of NF-kappaB-regulated genes, cyclin D1 and IL-6, were augmented in response to mechanical strain. Cyclic strain also increased the activity of Rho GTPases, especially Rac-1. The inhibition of Rho GTPases activity, by overexpression of Rho GDP dissociation inhibitor (Rho-GDI), inhibited the strain-induced activation of NF-kappaB in C2C12 cells. Overexpression of either NF-kappaB inhibitory protein IkappaBalphaDeltaN (a degradation resistant mutant IkappaBalpha) or Rho-GDI blocked the strain-induced proliferation of C2C12 cells. Furthermore, overexpression of FRNK, a dominant negative mutant of focal adhesion kinase (FAK), inhibited the strain-induced proliferation of C2C12 cells. Our study demonstrates that cyclic mechanical strain inhibits myogenesis through the activation of FAK, Rac-1, and NF-kappaB.
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Affiliation(s)
- Ashok Kumar
- Department of Medicine, Pulmonary and Critical Care Section, Suite 520B, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
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35
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Damo LA, Snyder PW, Franklin DS. Tumorigenesis in p27/p53- and p18/p53-double null mice: functional collaboration between the pRb and p53 pathways. Mol Carcinog 2005; 42:109-20. [PMID: 15584024 DOI: 10.1002/mc.20068] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Mice lacking both p18(Ink4c) and p27(Kip1) develop a tumor spectrum similar to pRb(+/-) mice, and loss of p53 function accelerates tumorigenesis in pRb(+/-) mice. We hypothesized that codeletion of either p18 or p27 in conjunction with p53 deletion will also accelerate tumorigenesis. Mice lacking both p18 and p53 develop several tumors not reported in either single null genotype, including hepatocellular carcinoma, testicular choriocarcinoma, hemangiosarcoma, leiomyosarcoma, fibrosarcoma, and osteosarcoma. Mice lacking both p27 and p53 exhibit a decreased lifespan and develop unique tumors, including papillary carcinoma of the colon, hemangiosarcoma, and leiomyosarcoma. In both p18/p53 and p27/p53 double null genotypes, the incidence and spectra of tissues that develop lymphoma are also increased, as compared to the single null genotypes. The development of p27/p53 double null colon tumors correlates with secondary changes in cell-cycle protein expression and CDK (cyclin-dependent kinase) activity, perhaps contributing to the progression of colorectal cancer. We concluded that p18 and p27 can, not only functionally collaborate with one another, but also can independently collaborate with p53 to modulate the cell cycle and suppress tumorigenesis in a tissue-specific manner.
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Affiliation(s)
- Lorna A Damo
- Department of Biological Sciences, Purdue University, 201 South University Street, West Lafayette, IN 47097-1392, USA
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36
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Cabane C, Coldefy AS, Yeow K, Dérijard B. The p38 pathway regulates Akt both at the protein and transcriptional activation levels during myogenesis. Cell Signal 2005; 16:1405-15. [PMID: 15381256 DOI: 10.1016/j.cellsig.2004.05.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2004] [Revised: 04/27/2004] [Accepted: 05/12/2004] [Indexed: 10/26/2022]
Abstract
The molecular signalling pathways governing skeletal muscle differentiation remain unclear. Recent work has demonstrated that both the phosphatidylinositol 3-kinase (PI3K)/Akt and p38 pathways play important roles in myogenesis. Here, we describe the interactions between these pathways in C2C12 cells. Overall, our results suggest that Akt acts downstream of p38 in myogenic cell differentiation. Activating the p38 pathway results in the concurrent activation of Akt; conversely, activating Akt does not affect p38. We have analysed Akt messenger RNA and protein levels in a C2C12 cell line stably expressing a dominant negative (DN) form of the p38 activator MKK3. Compared to control cells, this cell line exhibits reduced levels of Akt messenger RNA and total protein. In addition, blocking the p38 pathway during differentiation inhibits Akt activation. Our results show for the first time that p38 can directly affect Akt at the transcriptional level as well as at the protein activation level during myogenic differentiation.
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Affiliation(s)
- Candice Cabane
- UMR CNRS 6548, Laboratoire de Physiologie Cellulaire et Moléculaire, Université de Nice-Sophia Antipolis, Faculté des Sciences, 28 Avenue Valrose, 06108 Nice, France.
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37
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Wadhwa R, Yaguchi T, Kaur K, Suyama E, Kawasaki H, Taira K, Kaul SC. Use of a Randomized Hybrid Ribozyme Library for Identification of Genes Involved in Muscle Differentiation. J Biol Chem 2004; 279:51622-9. [PMID: 15448151 DOI: 10.1074/jbc.m407428200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
We have employed the hybrid hammerhead ribozyme-based gene discovery system for identification of genes functionally involved in muscle differentiation using in vitro myoblast differentiation assay. The major muscle regulatory genes (MyoD1, Mylk, myosin, myogenin, and Myf5) were identified endorsing the validity of this method. Other gene targets included tumor suppressors and cell cycle regulators (p19ARF and p21WAF1), FGFR-4, fibronectin, Prkg2, Pdk4, fem, and six novel proteins. Functional involvement of three of the identified targets in myoblast differentiation was confirmed by their specific knockdown using ribozymes and siRNA. Besides demonstrating a simple and an effective method of isolation of gene functions involved in muscle differentiation, we report for the first time that overexpression of Fem, a member of the sex-determining family of proteins, caused accelerated myotube formation, and its targeting deferred myoblast differentiation. This functional gene screening is not only helpful in understanding the molecular pathways of muscle differentiation but also to design molecular strategies for myopathologic therapies.
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Affiliation(s)
- Renu Wadhwa
- Gene Function Research Center, National Institute of Advanced Industrial Science & Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562, Japan
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38
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Myers TK, Andreuzza SE, Franklin DS. p18INK4c and p27KIP1 are required for cell cycle arrest of differentiated myotubes. Exp Cell Res 2004; 300:365-78. [PMID: 15475001 DOI: 10.1016/j.yexcr.2004.07.024] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2003] [Revised: 07/13/2004] [Indexed: 10/26/2022]
Abstract
Myogenic differentiation is characterized by permanent and irreversible cell cycle withdrawal and increased resistance to apoptosis. These functions correlate with changes in expression and activity of several cyclin-dependent kinase inhibitors, including p18, p21, and p27. In this study, we examined the requirements for p18, p21, and p27 in initiating growth arrest in multinucleated myotubes under differentiation conditions and in maintaining terminal arrest upon restimulation of differentiated myotubes with mitogenic signals. Under differentiation conditions, only p27(-/-) or p18(-/-)p27(-/-) myotubes are capable of reentering the cell cycle and synthesizing DNA at a very low frequency. Escape from cell cycle arrest was significantly greater in p18(-/-)p27(-/-) myotubes than in p27(-/-) myotubes. Stimulation of differentiated cultures with a mitogen-rich growth medium enhances p18(-/-)p27(-/-) myotube proliferation to encompass approximately half of the nuclei. p18(-/-)p21(-/-) and p21(-/-)p27(-/-) myotubes remain terminally arrested. Nuclei within individual restimulated p18(-/-)p27(-/-) myotubes can be found in all phases of the cell cycle, and a myotube can be multiphasic without any obvious deleterious effects. Increasing the time of differentiation or serum stimulation of p18(-/-)p27(-/-) myotubes neither increases the proliferation index of the myotube nuclei, nor does it alter the percentage of nuclei in each of the cell cycle phases. During the first 24 h of serum stimulation, the p18(-/-)p27(-/-) myotube nuclei that escape G0 arrest will rearrest in either S or G2 phase, without either mitosis or endoreplication. Apoptosis is increased in restimulated p18(-/-)p27(-/-) myotube nuclei, but is not specific for any cell cycle phase. These results suggest a collaborative role for p18 and p27 in initiating and maintaining G0 arrest during myogenic differentiation. While p18 and p27 appear to be essential in initiating G0 arrest in a proportion of postmitotic myotube nuclei, there must be another cell cycle inhibitor protein that functions with p18 and p27 in maintaining terminal arrest. We propose that the combined rate-limiting expressions of p18, p27, and this other inhibitor determine whether the myotube nuclei will remain postmitotic, or reenter the cell cycle, and if the nuclei escape G0 arrest, in which phase of the cell cycle the nuclei will ultimately rearrest.
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Affiliation(s)
- Terri K Myers
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
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39
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Figliola R, Maione R. MyoD induces the expression of p57Kip2 in cells lacking p21Cip1/Waf1: overlapping and distinct functions of the two cdk inhibitors. J Cell Physiol 2004; 200:468-75. [PMID: 15254975 DOI: 10.1002/jcp.20044] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The myogenic factor MyoD induces the expression of the cdk inhibitor p21 to promote cell cycle withdrawal in differentiating myoblasts. Although the cdk inhibitor p57 is also highly expressed in skeletal muscle and is thought to redundantly control myogenesis, little is known about its regulation, that has been suggested to be independent of MyoD. Here we show, for the first time, that MyoD is capable to induce the expression of p57. Intriguingly, this ability is restricted to cells lacking p21, suggesting that the two cdk inhibitors may be expressed in different muscle cell lineages. We also suggest that the functions of p21 and p57 in myoblast cells are only in part redundant. In fact, while the two cdk inhibitors play a similar role in cells undergoing G1 arrest during MyoD-induced differentiation, p57 does not replace p21 in cells escaping G1 arrest and undergoing MyoD-induced apoptosis. This difference can be ascribed both to a different subcellular localization and to a differential ability of the two cdk inhibitors to interact with cell cycle regulators.
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Affiliation(s)
- Rocco Figliola
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biotecnologie Cellulari ed Ematologia, Sezione di Genetica Molecolare, Università di Roma La Sapienza, Viale Regina Elena, Roma, Italy
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40
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Morishita A, Masaki T, Yoshiji H, Nakai S, Ogi T, Miyauchi Y, Yoshida S, Funaki T, Uchida N, Kita Y, Funakoshi F, Usuki H, Okada S, Izuishi K, Watanabe S, Kurokohchi K, Kuriyama S. Reduced expression of cell cycle regulator p18(INK4C) in human hepatocellular carcinoma. Hepatology 2004; 40:677-86. [PMID: 15349907 DOI: 10.1002/hep.20337] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Cyclins, cyclin-dependent kinases (Cdks), and Cdk inhibitors (CdkIs) are frequently altered in human cancer. p18INK4C, a member of the INK4 family of CdkIs, is a potential tumor-suppressor gene product. However, the expression of p18INK4C in hepatocellular carcinoma (HCC) remains unknown. The aim of this study was to examine the expression of p18INK4C in various liver diseases including HCC and to assess its clinical significance in HCC. To that end, we examined the expression of p18INK4C by immunohistochemistry in various liver diseases, including 51 HCCs, and also studied the relationship between p18INK4C expression, the phosphorylation of retinoblastoma protein (pRb), and the activity level of Cdk4 and Cdk6. Immunohistochemical analysis revealed the frequent loss of p18INK4C expression in HCC, especially in poorly differentiated HCC. The loss of p18INK4C expression was shown to be associated with a poor prognosis compared with that associated with p18INK4C- positivity. Further, the kinase activity of Cdk4 was found to be higher in p18INK4C-negative HCCs than in p18INK4C- positive HCCs. However, the level of Cdk6 activity was similar in the 2 groups of HCCs. In p18INK4C- positive HCCs, p18INK4C dominantly interacted with Cdk4 rather than with Cdk6. pRb phosphorylated at serine(Ser) 780 was detected more frequently in p18INK4C - negative than in p18INK4C - positive HCCs. In conclusion, the loss of p18INK4C expression may play a role in the differentiation and development of HCC through the up-regulation of Cdk4 activity.
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Affiliation(s)
- Asahiro Morishita
- Third Department of Internal Medicine, Kagawa Medical University, Kagawa, Japan
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41
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LaRue KEA, Khalil M, Freyer JP. Microenvironmental regulation of proliferation in multicellular spheroids is mediated through differential expression of cyclin-dependent kinase inhibitors. Cancer Res 2004; 64:1621-31. [PMID: 14996720 DOI: 10.1158/0008-5472.can-2902-2] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Multicellular spheroids composed of transformed cells are known to mimic the growth characteristics of tumors and to develop gradients in proliferation with increasing size. This progressive accumulation of quiescent cells is presumably an active process that occurs in response to the microenvironmental stresses that develop within the three-dimensional structure, and, yet, little is known regarding either the signals that induce the cell cycle arrest or the molecular basis for the halt in proliferation. We have previously reported that regulation of cyclin-dependent kinase (CDK) inhibitors (CKIs) differs in monolayer versus spheroid cell culture. In this study, we have examined the expression of three CKIs in EMT6 mouse mammary carcinoma and MEL28 human melanoma spheroids, as a function both of spheroid size and of location within the spheroid. We report that expression of the CKIs p18(INK4c), p21(waf1/cip1), and p27(Kip1) all increase as the spheroid grows and develops a quiescent cell fraction. However, by examining protein expression in discrete regions of the spheroid, we have found that only p18(INK4c) and p27(Kip1) expression positively correlate with growth arrest, whereas p21(waf1/cip1) is expressed predominantly in proliferating cells. Further analysis indicated that, in the quiescent cells, p18(INK4c) is found in increasing association with CDK6, whereas p27(Kip1) associates predominantly with CDK2. In MEL28 cells, CDK2 activity is completely abrogated in the inner regions of the spheroid, whereas in EMT6 cells, CDK2 activity decreases in accordance with a decrease in expression. We also observed a decrease in all cell cycle regulatory proteins in the innermost spheroid fraction, including CDKs, CKIs, and cyclins. Induction of CKIs from separate families, as well as their association with distinct target CDKs, suggests that there may be multiple checkpoints activated to ensure cell cycle arrest in non-growth-conducive environments. Furthermore, because very similar observations were made in both a human melanoma cell line and a mouse mammary carcinoma cell line, our results indicate that these checkpoints, as well as the signal transduction pathways that activate them, are highly conserved.
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Affiliation(s)
- Karen E A LaRue
- Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
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42
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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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43
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Li MH, Ito D, Sanada M, Odani T, Hatori M, Iwase M, Nagumo M. Effect of 5-fluorouracil on G1 phase cell cycle regulation in oral cancer cell lines. Oral Oncol 2004; 40:63-70. [PMID: 14662417 DOI: 10.1016/s1368-8375(03)00136-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
5-fluorouracil (5-FU) has been widely used for chemotherapy of head and neck cancer, and is known to affect the cell cycle and induce apoptotic death of cancer cells. However, the molecular actions of 5-FU on the cell cycle regulatory mechanism have not been fully explained. Herein we analyzed the effects of 5-FU on the expression of G1/S-related cell cycle regulators in oral cancer cell lines. In vitro 5-FU treatment of oral cancer cells resulted in an increase in G1/S phase cells. p21 expression was augmented by 5-FU without any notable changes in p53 expression. A remarkable up-regulation of cyclin E and a concomitant down-regulation of cyclin D were observed after 24 h 5-FU treatment. Our results suggest that 5-FU-induced changes in cell cycle regulation of oral cancer cells might associate with an alteration of G1 cyclins expression. p21 was remarkably up-regulated, but it was speculated that its activity might be cancelled by an increased binding to CDK4.
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Affiliation(s)
- Ming-Heng Li
- Second Department of Oral and Maxillofacial Surgery, School of Dentistry, Showa University, Tokyo 145-8515, Japan.
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44
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Tomczak KK, Marinescu VD, Ramoni MF, Sanoudou D, Montanaro F, Han M, Kunkel LM, Kohane IS, Beggs AH. Expression profiling and identification of novel genes involved in myogenic differentiation. FASEB J 2003; 18:403-5. [PMID: 14688207 DOI: 10.1096/fj.03-0568fje] [Citation(s) in RCA: 149] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Skeletal muscle differentiation is a complex, highly coordinated process that relies on precise temporal gene expression patterns. To better understand this cascade of transcriptional events, we used expression profiling to analyze gene expression in a 12-day time course of differentiating C2C12 myoblasts. Cluster analysis specific for time-ordered microarray experiments classified 2895 genes and ESTs with variable expression levels between proliferating and differentiating cells into 22 clusters with distinct expression patterns during myogenesis. Expression patterns for several known and novel genes were independently confirmed by real-time quantitative RT-PCR and/or Western blotting and immunofluorescence. MyoD and MEF family members exhibited unique expression kinetics that were highly coordinated with cell-cycle withdrawal regulators. Among genes with peak expression levels during cell cycle withdrawal were Vcam1, Itgb3, Itga5, Vcl, as well as Ptger4, a gene not previously associated with the process of myogenesis. One interesting uncharacterized transcript that is highly induced during myogenesis encodes several immunoglobulin repeats with sequence similarity to titin, a large sarcomeric protein. These data sets identify many additional uncharacterized transcripts that may play important functions in muscle cell proliferation and differentiation and provide a baseline for comparison with C2C12 cells expressing various mutant genes involved in myopathic disorders.
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Affiliation(s)
- Kinga K Tomczak
- Genetics Division, Children's Hospital, Boston, Massachusetts 02115, USA
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45
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Cao Y, Zhao Z, Gruszczynska-Biegala J, Zolkiewska A. Role of metalloprotease disintegrin ADAM12 in determination of quiescent reserve cells during myogenic differentiation in vitro. Mol Cell Biol 2003; 23:6725-38. [PMID: 12972593 PMCID: PMC193919 DOI: 10.1128/mcb.23.19.6725-6738.2003] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Skeletal myoblasts grown in vitro and induced to differentiate either form differentiated multinucleated myotubes or give rise to quiescent, undifferentiated "reserve cells" that share several characteristics with muscle satellite cells. The mechanism of determination of reserve cells is poorly understood. We find that the expression level of the metalloprotease disintegrin ADAM12 is much higher in proliferating C2C12 myoblasts and in reserve cells than in myotubes. Inhibition of ADAM12 expression in differentiating C2C12 cultures by small interfering RNA is accompanied by lower expression levels of both quiescence markers (retinoblastoma-related protein p130 and cell cycle inhibitor p27) and differentiation markers (myogenin and integrin alpha7A isoform). Overexpression of ADAM12 in C2C12 cells under conditions that promote cell cycle progression leads to upregulation of p130 and p27, cell cycle arrest, and downregulation of MyoD. Thus, enhanced expression of ADAM12 induces a quiescence-like phenotype and does not stimulate differentiation. We also show that the region extending from the disintegrin to the transmembrane domain of ADAM12 and containing cell adhesion activity as well as the cytoplasmic domain of ADAM12 are required for ADAM12-mediated cell cycle arrest, while the metalloprotease domain is not essential. Our results suggest that ADAM12-mediated adhesion and/or signaling may play a role in determination of the pool of reserve cells during myoblast differentiation.
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Affiliation(s)
- Yi Cao
- Department of Biochemistry, Kansas State University, Manhattan, Kansas 66506, USA
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46
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Ilyin GP, Glaise D, Gilot D, Baffet G, Guguen-Guillouzo C. Regulation and role of p21 and p27 cyclin-dependent kinase inhibitors during hepatocyte differentiation and growth. Am J Physiol Gastrointest Liver Physiol 2003; 285:G115-27. [PMID: 12646420 DOI: 10.1152/ajpgi.00309.2002] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Unlike a large number of cell types that undergo terminal differentiation associated with permanent withdrawal from the cell cycle, mature quiescent hepatocytes retain high proliferative potential. We report here a specific behavior of members of the Cip/Kip family of cyclin-dependent kinase (Cdk) inhibitors during development of the rat liver and proliferation of normal hepatocytes. Expression of p21, p27, and p57 transcripts and proteins was downregulated during the differentiation process to low or undetectable levels in adult liver. In contrast to p27, p21 protein increased in a mitogen-dependent manner in isolated hepatocytes and its expression pattern correlated with that of cyclin D1. In proliferating hepatocytes, p21 was predominantly associated with cyclin D1, these proteins were colocalized in the nucleus and p21-associated retinoblastoma protein (pRb) kinase activity increased in parallel with that of cyclin D1. Overexpression of p21 in mitogen-stimulated hepatocytes reduced DNA synthesis. In contrast, inhibition of p21 expression by antisense or small interfering RNAs oligonucleotides accelerated S phase entry. Finally, expression of p21 and cyclin D1, but not p27 proteins was regulated by MAPK kinase/extracellular signal-regulated kinase and phosphatidylinositol 3-kinase-ferric-reducing ability power/mammalian target of rapamycin signal transduction pathways. In conclusion, these results demonstrate a specific and differential regulation of p21 and p27 during hepatocyte differentiation and proliferation that may contribute to the control of quiescent differentiated hepatic cell proliferating activity.
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Affiliation(s)
- Gennady P Ilyin
- Institut National de la Santé et de la Recherche Médicale U522, Avenue de la Bataille Flandre/Dunkerque, Hôpital Pontchaillou, 35033 Rennes Cedex, France.
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47
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Luedde T, Rodriguez ME, Tacke F, Xiong Y, Brenner DA, Trautwein C. p18(INK4c) collaborates with other CDK-inhibitory proteins in the regenerating liver. Hepatology 2003; 37:833-41. [PMID: 12668976 DOI: 10.1053/jhep.2003.50136] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
p18(INK4c) belongs to the family of cyclin-dependent kinase inhibitory proteins that target the cyclin-dependent kinases and inhibit their catalytic activity. The role of p18(INK4c) for cell cycle progression in vivo is characterized poorly. Therefore, we studied the expression and physiologic relevance of p18 in quiescent and proliferating hepatocytes during liver regeneration. For our analysis we used single- (p18[INK4c], p27[KIP1], p21[CIP1/WAF1]), and double-mutant (p18/p21, p18/p27) mice. p18 expression was found in quiescent hepatocytes and a slight up-regulation was evident after partial hepatectomy (PH). p18 knockout animals showed normal cell cycle progression after PH. However, when p18/p21 and p18/p27 double-mutant mice were used, differences in cell cycle progression were evident compared with wild-type (wt) and single knockout animals. In p18/p21 knockout animals, the G1 phase was shortened as evidenced by an earlier onset of cyclin D and proliferating cell nuclear antigen (PCNA) expression and cyclin-dependent kinase (CDK) activation after PH. In contrast, in p18/p27 knockout animals, the G1 phase was unchanged, but the amount of proliferating hepatocytes (5-bromo-2'-deoxyuridine [BrdU] and PCNA positive) 48 hours after PH was elevated. In conclusion, our results suggest that p18 is involved in cell cycle progression after PH. Additionally we provide evidence that timing and strength of DNA synthesis in hepatocytes after PH is regulated tightly through the collaboration of different cell cycle inhibitors.
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Affiliation(s)
- Tom Luedde
- Department of Gastroenterology, Hepatology and Endocrinology, Medizinische Hochschule Hannover, Hannover, Germany
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48
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Cabane C, Englaro W, Yeow K, Ragno M, Dérijard B. Regulation of C2C12 myogenic terminal differentiation by MKK3/p38alpha pathway. Am J Physiol Cell Physiol 2003; 284:C658-66. [PMID: 12444016 DOI: 10.1152/ajpcell.00078.2002] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The signal transduction pathways connecting cell surface receptors to the activation of muscle-specific promoters and leading to myogenesis are still largely unknown. Recently, a contribution of the p38 mitogen-activated protein kinase (MAPK) pathway to this process was evoked through the use of pharmacological inhibitors. We used several mutants of the kinases composing this pathway to modulate the activity of the muscle-specific myosin light chain and myogenin promoters in C2C12 cells by transient transfections. In addition, we show for the first time, using a stable C2C12 cell line expressing a dominant-negative form of the p38 activator MAPK kinase (MKK)3, that a functional p38 MAPK pathway is indeed required for terminal muscle cell differentiation. The most obvious phenotype of this cell line, besides the inhibition of the activation of p38, is its inability to undergo terminal differentiation. This phenotype is accompanied by a drastic inhibition of cell cycle and myogenesis markers such as p21, p27, MyoD, and troponin T, as well as a profound disorganization of the cytoskeleton.
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MESH Headings
- Animals
- Cell Cycle Proteins/metabolism
- Cell Differentiation/drug effects
- Cell Differentiation/genetics
- Cells, Cultured
- Cyclin-Dependent Kinase Inhibitor p27
- MAP Kinase Kinase 3
- MAP Kinase Kinase Kinase 1
- Mice
- Mitogen-Activated Protein Kinase 14
- Mitogen-Activated Protein Kinase Kinases/drug effects
- Mitogen-Activated Protein Kinase Kinases/genetics
- Mitogen-Activated Protein Kinase Kinases/metabolism
- Mitogen-Activated Protein Kinases/drug effects
- Mitogen-Activated Protein Kinases/genetics
- Mitogen-Activated Protein Kinases/metabolism
- Muscle Fibers, Skeletal/cytology
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/enzymology
- Muscle Fibers, Skeletal/metabolism
- Muscle, Skeletal/cytology
- Muscle, Skeletal/embryology
- Muscle, Skeletal/enzymology
- MyoD Protein/antagonists & inhibitors
- MyoD Protein/metabolism
- Myoblasts, Skeletal/cytology
- Myoblasts, Skeletal/enzymology
- Myogenin/antagonists & inhibitors
- Myogenin/metabolism
- Myosin Heavy Chains/drug effects
- Myosin Heavy Chains/metabolism
- Myosin Light Chains/antagonists & inhibitors
- Myosin Light Chains/metabolism
- Protein Serine-Threonine Kinases/antagonists & inhibitors
- Protein Serine-Threonine Kinases/metabolism
- Protein-Tyrosine Kinases/drug effects
- Protein-Tyrosine Kinases/genetics
- Protein-Tyrosine Kinases/metabolism
- Tumor Suppressor Proteins/metabolism
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Affiliation(s)
- Candice Cabane
- Unité Mixte de Recherche Centre National de la Recherche Scientifique 6548, Laboratoire de Physiologie Cellulaire et Moléculaire, Faculté des Sciences, Université de Nice-Sophia Antipolis, France
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49
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Bai F, Pei XH, Godfrey VL, Xiong Y. Haploinsufficiency of p18(INK4c) sensitizes mice to carcinogen-induced tumorigenesis. Mol Cell Biol 2003; 23:1269-77. [PMID: 12556487 PMCID: PMC141153 DOI: 10.1128/mcb.23.4.1269-1277.2003] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2002] [Revised: 11/05/2002] [Accepted: 11/18/2002] [Indexed: 11/20/2022] Open
Abstract
The INK4 family of cyclin-dependent kinase (CDK) inhibitors negatively regulates cyclin D-dependent CDK4 and CDK6 and thereby retains the growth-suppressive function of Rb family proteins. Mutations in the CDK4 gene conferring INK4 resistance are associated with familial and sporadic melanoma in humans and result in a wide spectrum of tumors in mice. Whereas loss of function of other INK4 genes in mice leads to little or no tumor development, targeted deletion of p18(INK4c) causes spontaneous pituitary tumors and lymphoma late in life. Here we show that treatment of p18 null and heterozygous mice with a chemical carcinogen resulted in tumor development at an accelerated rate. The remaining wild-type allele of p18 was neither mutated nor silenced in tumors derived from heterozygotes. Hence, p18 is a haploinsufficient tumor suppressor in mice.
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Affiliation(s)
- Feng Bai
- Lineberger Comprehensive Cancer Center. Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7295, USA
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50
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Blais A, Monté D, Pouliot F, Labrie C. Regulation of the human cyclin-dependent kinase inhibitor p18INK4c by the transcription factors E2F1 and Sp1. J Biol Chem 2002; 277:31679-93. [PMID: 12077144 DOI: 10.1074/jbc.m204554200] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The p18(INK4c) cyclin-dependent kinase inhibitor is an important regulator of cell cycle progression and cellular differentiation. We and others found that overexpressed E2F proteins up-regulate p18 expression. To better understand this phenomenon, we performed a functional analysis of the human p18 promoter. Deletion studies revealed that the E2F-responsive elements of the promoter are located within 131 bp upstream of the transcription start site. This region contains putative Sp1- and E2F-binding sites. Mutational inactivation of these elements revealed that the Sp1 sites were important for the basal activity of the promoter but could also mediate the effects of E2F1 on the p18 promoter. Moreover, we found that E2F1 and Sp1 can synergistically enhance the activity of the proximal p18 promoter. Gel shift analyses using p18 promoter-derived probes led to the identification of several multiprotein complexes that were found to contain different combinations of E2F proteins and/or Sp1. Recombinant E2F1 was also capable of binding to the E2F-binding sites. Chromatin immunoprecipitation experiments demonstrated that E2F1 and E2F4 associate with the p18 promoter in unperturbed cells. Based on these findings, we conclude that E2F proteins and Sp1 play an important role in the control of p18 expression.
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Affiliation(s)
- Alexandre Blais
- Molecular Endocrinology and Oncology Research Center, Centre Hospitalier de l'Université Laval Research Center, Centre Hospitalier Universitaire de Quebec, Sainte-Foy, G1V 4G2 Quebec, Canada
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