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Yang S, Golkaram M, Oh S, Oh Y, Cho Y, Yoe J, Ju S, Lalli MA, Park SY, Lee Y, Jang J. ETV4 is a mechanical transducer linking cell crowding dynamics to lineage specification. Nat Cell Biol 2024; 26:903-916. [PMID: 38702503 PMCID: PMC11178500 DOI: 10.1038/s41556-024-01415-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 04/03/2024] [Indexed: 05/06/2024]
Abstract
Dynamic changes in mechanical microenvironments, such as cell crowding, regulate lineage fates as well as cell proliferation. Although regulatory mechanisms for contact inhibition of proliferation have been extensively studied, it remains unclear how cell crowding induces lineage specification. Here we found that a well-known oncogene, ETS variant transcription factor 4 (ETV4), serves as a molecular transducer that links mechanical microenvironments and gene expression. In a growing epithelium of human embryonic stem cells, cell crowding dynamics is translated into ETV4 expression, serving as a pre-pattern for future lineage fates. A switch-like ETV4 inactivation by cell crowding derepresses the potential for neuroectoderm differentiation in human embryonic stem cell epithelia. Mechanistically, cell crowding inactivates the integrin-actomyosin pathway and blocks the endocytosis of fibroblast growth factor receptors (FGFRs). The disrupted FGFR endocytosis induces a marked decrease in ETV4 protein stability through ERK inactivation. Mathematical modelling demonstrates that the dynamics of cell density in a growing human embryonic stem cell epithelium precisely determines the spatiotemporal ETV4 expression pattern and, consequently, the timing and geometry of lineage development. Our findings suggest that cell crowding dynamics in a stem cell epithelium drives spatiotemporal lineage specification using ETV4 as a key mechanical transducer.
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Affiliation(s)
- Seungbok Yang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Mahdi Golkaram
- Department of Mechanical Engineering, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - Seyoun Oh
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Yujeong Oh
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Yoonjae Cho
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Jeehyun Yoe
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Sungeun Ju
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Matthew A Lalli
- Seaver Autism Center for Research and Treatment at Mount Sinai, New York, NY, USA
| | - Seung-Yeol Park
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Yoontae Lee
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Jiwon Jang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea.
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2
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Lin WH, Cooper LM, Anastasiadis PZ. Cadherins and catenins in cancer: connecting cancer pathways and tumor microenvironment. Front Cell Dev Biol 2023; 11:1137013. [PMID: 37255594 PMCID: PMC10225604 DOI: 10.3389/fcell.2023.1137013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 05/03/2023] [Indexed: 06/01/2023] Open
Abstract
Cadherin-catenin complexes are integral components of the adherens junctions crucial for cell-cell adhesion and tissue homeostasis. Dysregulation of these complexes is linked to cancer development via alteration of cell-autonomous oncogenic signaling pathways and extrinsic tumor microenvironment. Advances in multiomics have uncovered key signaling events in multiple cancer types, creating a need for a better understanding of the crosstalk between cadherin-catenin complexes and oncogenic pathways. In this review, we focus on the biological functions of classical cadherins and associated catenins, describe how their dysregulation influences major cancer pathways, and discuss feedback regulation mechanisms between cadherin complexes and cellular signaling. We discuss evidence of cross regulation in the following contexts: Hippo-Yap/Taz and receptor tyrosine kinase signaling, key pathways involved in cell proliferation and growth; Wnt, Notch, and hedgehog signaling, key developmental pathways involved in human cancer; as well as TGFβ and the epithelial-to-mesenchymal transition program, an important process for cancer cell plasticity. Moreover, we briefly explore the role of cadherins and catenins in mechanotransduction and the immune tumor microenvironment.
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Effect of serum starvation and contact inhibition on dermal fibroblast cell cycle synchronization in two species of wild felids and domestic cat. ANNALS OF ANIMAL SCIENCE 2022. [DOI: 10.2478/aoas-2022-0042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
Cell cycle synchronization of donor cells is an important step in mammalian somatic cell nuclear transfer (SCNT). This study was designed to compare the efficiency of serum starvation (Ss) and contact inhibition (cI) on cell cycle synchronization of jaguarundi, manul, and domestic cat skin fibroblasts, in the production of G0/G1 cells suitable for SCNT in felids. Ss was performed after the growing (G) cells reached 40–50% (G50+Ss), 60–70% (G70+Ss) and full confluency (Fc), i.e. in association with cI (cI+Ss). Frozen-thawed cells were cultured to the given state of confluency (d0; controls), and subjected to Ss or cI for 1, 3, and 5 days (d). In manul, the effect of Ss on arresting fibroblasts in the G0/G1 phase was noted after just 1d of culture at G70 confluence, while G50+Ss and cI+Ss were effective after 5d of treatment. In jaguarundi, 1–5d of G50+Ss and 5d of G70+Ss increased the percentage of G0/G1 cells versus d0 (P<0.01), with 5d of G70+Ss producing more (P<0.05) quiescent cells than after the same period of G50+Ss, cI+Ss and cI. In the domestic cat, Ss was efficient only after 3 and 5d of G50+Ss. In all species, cI alone failed to increase the proportion of G0/G1 cells compared to d0, however in the domestic cat, 5d of cI was more efficient than the same period of G50+Ss. In jaguarundi, >93% of cells were already in G0/G1 phase at d0 of Fc, suggesting that culture to Fc could be also a valuable method for fibroblast cell cycle synchronization in this species. In contrast to cI, prolonged Ss generated cell loss and could induce apoptosis and/or necrosis. In conclusion, Ss was the more efficient method for skin fibroblast cell cycle synchronization at the G0/G1 phase in manul, jaguarundi and the domestic cat. The response of cells to the treatments was species-specific, depending on cell confluence and duration of culture. This research may find application in preparing donor karyoplasts for SCNT in felids.
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Hirashima T. Mechanical Feedback Control for Multicellular Tissue Size Maintenance: A Minireview. Front Cell Dev Biol 2022; 9:820391. [PMID: 35096843 PMCID: PMC8795865 DOI: 10.3389/fcell.2021.820391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 12/27/2021] [Indexed: 11/13/2022] Open
Abstract
All living tissues and organs have their respective sizes, critical to various biological functions, such as development, growth, and homeostasis. As tissues and organs generally converge to a certain size, intrinsic regulatory mechanisms may be involved in the maintenance of size regulation. In recent years, important findings regarding size regulation have been obtained from diverse disciplines at the molecular and cellular levels. Here, I briefly review the size regulation of biological tissues from the perspective of control systems. This minireview focuses on how feedback systems engage in tissue size maintenance through the mechanical interactions of constituent cell collectives through intracellular signaling. I introduce a general framework of a feedback control system for tissue size regulation, followed by two examples: maintenance of epithelial tissue volume and epithelial tube diameter. The examples deliver the idea of how cellular mechano-response works for maintaining tissue size.
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Affiliation(s)
- Tsuyoshi Hirashima
- The Hakubi Center, Kyoto University, Kyoto, Japan
- Laboratory of Bioimaging and Cell Signaling, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
- Japan Science and Technology Agency, PRESTO, Kawaguchi, Japan
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5
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Bukkuri A, Adler FR. Viewing Cancer Through the Lens of Corruption: Using Behavioral Ecology to Understand Cancer. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.678533] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
All biological systems depend on signals for coordination: signals which pass information among agents that run the gamut from cells to organisms. However, their very importance makes signals vulnerable to subversion. How can a receiver know whether a signal is honest or deceptive? In other words, are signals necessarily a reliable indicator of agent quality or need? By drawing parallels to ecological phenomena ranging from begging by nestlings to social insects, we investigate the role of signal degradation in cancer. We thus think of cancer as a form of corruption, in which cells command huge resource investment through relatively cheap signals, just as relatively small bribes can leverage large profits. We discuss various mechanisms which prevent deceptive signaling in the natural world and within tissues. We show how cancers evolve ways to escape these controls and relate these back to evasion mechanisms in ecology. We next introduce two related concepts, co-option and collusion, and show how they play critical roles in ecology and cancer. Drawing on public policy, we propose new approaches to view treatment based on taxation, changing the incentive structure, and the recognition of corrupted signaling networks.
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Jafari Nivlouei S, Soltani M, Carvalho J, Travasso R, Salimpour MR, Shirani E. Multiscale modeling of tumor growth and angiogenesis: Evaluation of tumor-targeted therapy. PLoS Comput Biol 2021; 17:e1009081. [PMID: 34161319 PMCID: PMC8259971 DOI: 10.1371/journal.pcbi.1009081] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 07/06/2021] [Accepted: 05/14/2021] [Indexed: 12/12/2022] Open
Abstract
The dynamics of tumor growth and associated events cover multiple time and spatial scales, generally including extracellular, cellular and intracellular modifications. The main goal of this study is to model the biological and physical behavior of tumor evolution in presence of normal healthy tissue, considering a variety of events involved in the process. These include hyper and hypoactivation of signaling pathways during tumor growth, vessels' growth, intratumoral vascularization and competition of cancer cells with healthy host tissue. The work addresses two distinctive phases in tumor development-the avascular and vascular phases-and in each stage two cases are considered-with and without normal healthy cells. The tumor growth rate increases considerably as closed vessel loops (anastomoses) form around the tumor cells resulting from tumor induced vascularization. When taking into account the host tissue around the tumor, the results show that competition between normal cells and cancer cells leads to the formation of a hypoxic tumor core within a relatively short period of time. Moreover, a dense intratumoral vascular network is formed throughout the entire lesion as a sign of a high malignancy grade, which is consistent with reported experimental data for several types of solid carcinomas. In comparison with other mathematical models of tumor development, in this work we introduce a multiscale simulation that models the cellular interactions and cell behavior as a consequence of the activation of oncogenes and deactivation of gene signaling pathways within each cell. Simulating a therapy that blocks relevant signaling pathways results in the prevention of further tumor growth and leads to an expressive decrease in its size (82% in the simulation).
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Affiliation(s)
- Sahar Jafari Nivlouei
- Department of Mechanical Engineering, Isfahan University of Technology, Isafahan, Iran
- CFisUC, Department of Physics, University of Coimbra, Coimbra, Portugal
| | - M. Soltani
- Department of Mechanical Engineering, K. N. Toosi University of Technology, Tehran, Iran
- Department of Electrical and Computer Engineering, University of Waterloo, Ontario, Canada
- Centre for Biotechnology and Bioengineering (CBB), University of Waterloo, Waterloo, Ontario, Canada
- Advanced Bioengineering Initiative Center, Computational Medicine Center, K. N. Toosi University of Technology, Tehran, Iran
- Cancer Biology Research Center, Cancer Institute of Iran, Tehran University of Medical Sciences, Tehran, Iran
| | - João Carvalho
- CFisUC, Department of Physics, University of Coimbra, Coimbra, Portugal
| | - Rui Travasso
- CFisUC, Department of Physics, University of Coimbra, Coimbra, Portugal
| | | | - Ebrahim Shirani
- Department of Mechanical Engineering, Isfahan University of Technology, Isafahan, Iran
- Department of Mechanical Engineering, Foolad Institute of Technology, Fooladshahr, Iran
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7
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Systematic Review and Meta-Analysis of In Vitro Anti-Human Cancer Experiments Investigating the Use of 5-Aminolevulinic Acid (5-ALA) for Photodynamic Therapy. Pharmaceuticals (Basel) 2021; 14:ph14030229. [PMID: 33800109 PMCID: PMC8000125 DOI: 10.3390/ph14030229] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 02/26/2021] [Accepted: 02/27/2021] [Indexed: 12/11/2022] Open
Abstract
5-Aminolevulinic acid (5-ALA) is an amino acid derivative and a precursor of protoporphyrin IX (PpIX). The photophysical feature of PpIX is clinically used in photodynamic diagnosis (PDD) and photodynamic therapy (PDT). These clinical applications are potentially based on in vitro cell culture experiments. Thus, conducting a systematic review and meta-analysis of in vitro 5-ALA PDT experiments is meaningful and may provide opportunities to consider future perspectives in this field. We conducted a systematic literature search in PubMed to summarize the in vitro 5-ALA PDT experiments and calculated the effectiveness of 5-ALA PDT for several cancer cell types. In total, 412 articles were identified, and 77 were extracted based on our inclusion criteria. The calculated effectiveness of 5-ALA PDT was statistically analyzed, which revealed a tendency of cancer-classification-dependent sensitivity to 5-ALA PDT, and stomach cancer was significantly more sensitive to 5-ALA PDT compared with cancers of different origins. Based on our analysis, we suggest a standardized in vitro experimental protocol for 5-ALA PDT.
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8
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Structural Insight on Functional Regulation of Human MINERVA Protein. Int J Mol Sci 2020; 21:ijms21218186. [PMID: 33142954 PMCID: PMC7663100 DOI: 10.3390/ijms21218186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 10/28/2020] [Accepted: 10/30/2020] [Indexed: 11/17/2022] Open
Abstract
MINERVA (melanoma invasion by ERK), also known as FAM129B, is a member of the FAM129 protein family, which is only present in vertebrates. MINERVA is involved in key signaling pathways regulating cell survival, proliferation and apoptosis and found upregulated in many types of cancer promoting invasion. However, the exact function of the protein remains elusive. X-ray crystallographic methods were implemented to determine the crystal structure of MINERVAΔC, lacking C-terminal flexible region. Trypsin digestion was required before crystallization to obtain diffraction-quality crystals. While the N-terminal pleckstrin homology (PH) domain exhibits the typical fold of PH domains, lipid binding assay indicates specific affinity towards phosphatidic acid and inositol 3-phosphate. A helix-rich domain that constitutes the rest of the molecule demonstrates a novel L-shaped fold that encompasses the PH domain. The overall structure of MINERVAΔC with binding assays and cell-based experiments suggest plasma membrane association of MINERVA and its function seem to be tightly regulated by various motifs within the C-terminal flexible region. Elucidation of MINERVAΔC structure presents a novel fold for an α-helix bundle domain that would provide a binding platform for interacting partners.
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Fukuma Y, Inui T, Imashiro C, Kurashina Y, Takemura K. Homogenization of initial cell distribution by secondary flow of medium improves cell culture efficiency. PLoS One 2020; 15:e0235827. [PMID: 32667933 PMCID: PMC7983807 DOI: 10.1371/journal.pone.0235827] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 06/23/2020] [Indexed: 11/30/2022] Open
Abstract
Homogenization of the initial cell distribution is essential for effective cell
development. However, there are few previous reports on efficient cell seeding
methods, even though the initial cell distribution has a large effect on cell
proliferation. Dense cell regions have an inverse impact on cell development,
known as contact inhibition. In this study, we developed a method to homogenize
the cell seeding density using secondary flow, or Ekman transportation, induced
by orbital movement of the culture dish. We developed an orbital shaker device
that can stir the medium in a 35-mm culture dish by shaking the dish along a
circular orbit with 2 mm of eccentricity. The distribution of cells in the
culture dish can be controlled by the rotational speed of the orbital shaker,
enabling dispersion of the initial cell distribution. The experimental results
indicated that the cell density became most homogeneous at 61 rpm. We further
evaluated the cell proliferation after homogenization of the initial cell
density at 61 rpm. The results revealed 36% higher proliferation for the stirred
samples compared with the non-stirred control samples. The present findings
indicate that homogenization of the initial cell density by Ekman transportation
contributes to the achievement of higher cell proliferation.
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Affiliation(s)
- Yuki Fukuma
- School of Science for Open and Environmental Systems, Graduate School of
Science and Technology, Keio University, Yokohama, Kanagawa,
Japan
| | - Takumi Inui
- School of Science for Open and Environmental Systems, Graduate School of
Science and Technology, Keio University, Yokohama, Kanagawa,
Japan
| | - Chikahiro Imashiro
- Department of Mechanical Engineering, Faculty of Science and Technology,
Keio University, Yokohama, Kanagawa, Japan
- Institute of Advanced Biomedical Engineering and Science, Tokyo Women’s
Medical University, Tokyo, Japan
| | - Yuta Kurashina
- Department of Materials Science and Engineering, School of Materials and
Chemical Technology, Tokyo institute of Technology, Yokohama, Kanagawa,
Japan
| | - Kenjiro Takemura
- Department of Mechanical Engineering, Faculty of Science and Technology,
Keio University, Yokohama, Kanagawa, Japan
- * E-mail:
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Haneke K, Schott J, Lindner D, Hollensen AK, Damgaard CK, Mongis C, Knop M, Palm W, Ruggieri A, Stoecklin G. CDK1 couples proliferation with protein synthesis. J Cell Biol 2020; 219:e201906147. [PMID: 32040547 PMCID: PMC7054999 DOI: 10.1083/jcb.201906147] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 11/20/2019] [Accepted: 01/08/2020] [Indexed: 12/26/2022] Open
Abstract
Cell proliferation exerts a high demand on protein synthesis, yet the mechanisms coupling the two processes are not fully understood. A kinase and phosphatase screen for activators of translation, based on the formation of stress granules in human cells, revealed cell cycle-associated kinases as major candidates. CDK1 was identified as a positive regulator of global translation, and cell synchronization experiments showed that this is an extramitotic function of CDK1. Different pathways including eIF2α, 4EBP, and S6K1 signaling contribute to controlling global translation downstream of CDK1. Moreover, Ribo-Seq analysis uncovered that CDK1 exerts a particularly strong effect on the translation of 5'TOP mRNAs, which includes mRNAs encoding ribosomal proteins and several translation factors. This effect requires the 5'TOP mRNA-binding protein LARP1, concurrent to our finding that LARP1 phosphorylation is strongly dependent on CDK1. Thus, CDK1 provides a direct means to couple cell proliferation with biosynthesis of the translation machinery and the rate of protein synthesis.
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Affiliation(s)
- Katharina Haneke
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Center for Molecular Biology of Heidelberg University, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Johanna Schott
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Center for Molecular Biology of Heidelberg University, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Doris Lindner
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Center for Molecular Biology of Heidelberg University, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Anne Kruse Hollensen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | | | - Cyril Mongis
- Center for Molecular Biology of Heidelberg University, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Michael Knop
- Center for Molecular Biology of Heidelberg University, DKFZ-ZMBH Alliance, Heidelberg, Germany
- Cell Morphogenesis and Signal Transduction, German Cancer Research Center, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Wilhelm Palm
- Cell Signaling and Metabolism, German Cancer Research Center, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Alessia Ruggieri
- Department of Infectious Diseases, Molecular Virology, Center for Integrative Infectious Diseases Research, University of Heidelberg, Heidelberg, Germany
| | - Georg Stoecklin
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Center for Molecular Biology of Heidelberg University, DKFZ-ZMBH Alliance, Heidelberg, Germany
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Grimes DR, Fletcher AG. Close Encounters of the Cell Kind: The Impact of Contact Inhibition on Tumour Growth and Cancer Models. Bull Math Biol 2020; 82:20. [PMID: 31970500 PMCID: PMC6976547 DOI: 10.1007/s11538-019-00677-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Accepted: 12/02/2019] [Indexed: 01/24/2023]
Abstract
Cancer is a complex phenomenon, and the sheer variation in behaviour across different types renders it difficult to ascertain underlying biological mechanisms. Experimental approaches frequently yield conflicting results for myriad reasons, and mathematical modelling of cancer is a vital tool to explore what we cannot readily measure, and ultimately improve treatment and prognosis. Like experiments, models are underpinned by certain biological assumptions, variation of which can lead to divergent predictions. An outstanding and important question concerns contact inhibition of proliferation (CIP), the observation that proliferation ceases when cells are spatially confined by their neighbours. CIP is a characteristic of many healthy adult tissues, but it remains unclear to which extent it holds in solid tumours, which exhibit regions of hyper-proliferation, and apparent breakdown of CIP. What precisely occurs in tumour tissue remains an open question, which mathematical modelling can help shed light on. In this perspective piece, we explore the implications of different hypotheses and available experimental evidence to elucidate the implications of these scenarios. We also outline how erroneous conclusions about the nature of tumour growth may be arrived at by looking selectively at biological data in isolation, and how this might be circumvented.
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Affiliation(s)
- David Robert Grimes
- School of Physical Sciences, Dublin City University, Glasnevin, Dublin 9, Ireland.
- Department of Oncology, University of Oxford, Old Road Campus, Oxford, OX3 7DQ, UK.
| | - Alexander G Fletcher
- School of Mathematics and Statistics, University of Sheffield, Sheffield, S3 7RH, UK
- Bateson Centre, University of Sheffield, Sheffield, S10 2TN, UK
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Chen H, Zhong J, Wang J, Huang R, Qiao X, Wang H, Tan Z. Enhanced growth and differentiation of myoblast cells grown on E-jet 3D printed platforms. Int J Nanomedicine 2019; 14:937-950. [PMID: 30787608 PMCID: PMC6366362 DOI: 10.2147/ijn.s193624] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Skeletal muscle tissue engineering often involves the prefabrication of muscle tissues in vitro by differentiation and maturation of muscle precursor cells on a platform which provides an environment that facilitates the myogenic differentiation of the seeded cells. METHODS Poly lactic-co-glycolic acid (PLGA) 3D printed scaffolds, which simulate the highly complex structure of extracellular matrix (ECM), were fabricated by E-jet 3D printing in this study. The scaffolds were used as platforms, providing environment that aids in growth, differentiation and other properties of C2C12 myoblast cells. RESULTS The C2C12 myoblast cells grown on the PLGA 3D printed platforms had enhanced cell adhesion and proliferation. Moreover, the platforms were able to induce myogenic differentiation of the myoblast cells by promoting the formation of myotubes and up-regulating the expressions of myogenic genes (MyHC and MyOG). CONCLUSION The fabricated 3D printed platforms have excellent biocompatibility, thereby can potentially be used as functional cell culture platforms in skeletal tissue engineering and regeneration.
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Affiliation(s)
- Haoxiang Chen
- College of Biology, Hunan University, Changsha, Hunan 410082, China,
| | - Juchang Zhong
- College of Biology, Hunan University, Changsha, Hunan 410082, China,
| | - Jian Wang
- College of Biology, Hunan University, Changsha, Hunan 410082, China,
| | - Ruiying Huang
- College of Biology, Hunan University, Changsha, Hunan 410082, China,
| | - Xiaoyin Qiao
- College of Biology, Hunan University, Changsha, Hunan 410082, China,
| | - Honghui Wang
- College of Biology, Hunan University, Changsha, Hunan 410082, China,
| | - Zhikai Tan
- College of Biology, Hunan University, Changsha, Hunan 410082, China,
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The Temporal Regulation of S Phase Proteins During G 1. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1042:335-369. [PMID: 29357066 DOI: 10.1007/978-981-10-6955-0_16] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Successful DNA replication requires intimate coordination with cell-cycle progression. Prior to DNA replication initiation in S phase, a series of essential preparatory events in G1 phase ensures timely, complete, and precise genome duplication. Among the essential molecular processes are regulated transcriptional upregulation of genes that encode replication proteins, appropriate post-transcriptional control of replication factor abundance and activity, and assembly of DNA-loaded protein complexes to license replication origins. In this chapter we describe these critical G1 events necessary for DNA replication and their regulation in the context of both cell-cycle entry and cell-cycle progression.
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Abstract
E-cadherin is a key component of the adherens junctions that are integral in cell adhesion and maintaining epithelial phenotype of cells. Homophilic E-cadherin binding between cells is important in mediating contact inhibition of proliferation when cells reach confluence. Loss of E-cadherin expression results in loss of contact inhibition and is associated with increased cell motility and advanced stages of cancer. In this review we discuss the role of E-cadherin and its downstream signaling in regulation of contact inhibition and the development and progression of cancer.
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15
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Kwasnik A, von Kriegsheim A, Irving A, Pennington SR. Potential mechanisms of calcium dependent regulation of the mammalian cell cycle revealed by comprehensive unbiased label-free nLC-MS/MS quantitative proteomics. J Proteomics 2018; 170:151-166. [DOI: 10.1016/j.jprot.2017.08.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 08/03/2017] [Accepted: 08/05/2017] [Indexed: 01/27/2023]
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Abstract
In dividing cells, long-lived proteins are continuously diluted by being partitioned into newly formed daughter cells. Conversely, short-lived proteins are cleared from a cell primarily by proteolysis rather than cell division. Thus, when a cell stops dividing, there is a natural tendency for long-lived proteins to accumulate relative to short-lived proteins. This effect is disruptive to cells and leads to the accumulation of aged and damaged proteins over time. Here, we analyzed the degradation of thousands of proteins in dividing and nondividing (quiescent) skin cells. Our results demonstrate that quiescent cells avoid the accumulation of long-lived proteins by enhancing their degradation through pathways involving the lysosome. This mechanism may be important for promotion of protein homeostasis in aged organisms. In dividing cells, cytoplasmic dilution is the dominant route of clearance for long-lived proteins whose inherent degradation is slower than the cellular growth rate. Thus, as cells transition from a dividing to a nondividing state, there is a propensity for long-lived proteins to become stabilized relative to short-lived proteins, leading to alterations in the abundance distribution of the proteome. However, it is not known if cells mount a compensatory response to counter this potentially deleterious proteostatic disruption. We used a proteomic approach to demonstrate that fibroblasts selectively increase degradation rates of long-lived proteins as they transition from a proliferating to a quiescent state. The selective degradation of long-lived proteins occurs by the concurrent activation of lysosomal biogenesis and up-regulation of macroautophagy. Through this mechanism, quiescent cells avoid the accumulation of aged long-lived proteins that would otherwise result from the absence of cytoplasmic dilution by cell division.
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Warne DJ, Baker RE, Simpson MJ. Optimal Quantification of Contact Inhibition in Cell Populations. Biophys J 2017; 113:1920-1924. [PMID: 29032961 PMCID: PMC5685786 DOI: 10.1016/j.bpj.2017.09.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 09/04/2017] [Accepted: 09/15/2017] [Indexed: 02/07/2023] Open
Abstract
Contact inhibition refers to a reduction in the rate of cell migration and/or cell proliferation in regions of high cell density. Under normal conditions, contact inhibition is associated with the proper functioning tissues, whereas abnormal regulation of contact inhibition is associated with pathological conditions, such as tumor spreading. Unfortunately, standard mathematical modeling practices mask the importance of parameters that control contact inhibition through scaling arguments. Furthermore, standard experimental protocols are insufficient to quantify the effects of contact inhibition because they focus on data describing early time, low-density dynamics only. Here we use the logistic growth equation as a caricature model of contact inhibition to make recommendations as to how to best mitigate these issues. Taking a Bayesian approach, we quantify the trade off between different features of experimental design and estimates of parameter uncertainty so that we can reformulate a standard cell proliferation assay to provide estimates of both the low-density intrinsic growth rate, λ, and the carrying capacity density, K, which is a measure of contact inhibition.
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Affiliation(s)
- David J Warne
- School of Mathematical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Ruth E Baker
- Mathematical Institute, University of Oxford, Oxford, United Kingdom
| | - Matthew J Simpson
- School of Mathematical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia.
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Chen QY, Costa M. A comprehensive review of metal-induced cellular transformation studies. Toxicol Appl Pharmacol 2017; 331:33-40. [DOI: 10.1016/j.taap.2017.05.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 04/30/2017] [Accepted: 05/05/2017] [Indexed: 01/07/2023]
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19
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Welle KA, Zhang T, Hryhorenko JR, Shen S, Qu J, Ghaemmaghami S. Time-resolved Analysis of Proteome Dynamics by Tandem Mass Tags and Stable Isotope Labeling in Cell Culture (TMT-SILAC) Hyperplexing. Mol Cell Proteomics 2016; 15:3551-3563. [PMID: 27765818 DOI: 10.1074/mcp.m116.063230] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 10/03/2016] [Indexed: 12/20/2022] Open
Abstract
Recent advances in mass spectrometry have enabled system-wide analyses of protein turnover. By globally quantifying the kinetics of protein clearance and synthesis, these methodologies can provide important insights into the regulation of the proteome under varying cellular and environmental conditions. To facilitate such analyses, we have employed a methodology that combines metabolic isotopic labeling (Stable Isotope Labeling in Cell Culture - SILAC) with isobaric tagging (Tandem Mass Tags - TMT) for analysis of multiplexed samples. The fractional labeling of multiple time-points can be measured in a single mass spectrometry run, providing temporally resolved measurements of protein turnover kinetics. To demonstrate the feasibility of the approach, we simultaneously measured the kinetics of protein clearance and accumulation for more than 3000 proteins in dividing and quiescent human fibroblasts and verified the accuracy of the measurements by comparison to established non-multiplexed approaches. The results indicate that upon reaching quiescence, fibroblasts compensate for lack of cellular growth by globally downregulating protein synthesis and upregulating protein degradation. The described methodology significantly reduces the cost and complexity of temporally-resolved dynamic proteomic experiments and improves the precision of proteome-wide turnover data.
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Affiliation(s)
- Kevin A Welle
- From the ‡University of Rochester Mass Spectrometry Resource Laboratory, Rochester, NY
| | - Tian Zhang
- §Department of Biology, University of Rochester, Rochester, NY
| | - Jennifer R Hryhorenko
- From the ‡University of Rochester Mass Spectrometry Resource Laboratory, Rochester, NY
| | - Shichen Shen
- ¶Department of Pharmaceutical Sciences, University at Buffalo, Buffalo, NY
| | - Jun Qu
- ¶Department of Pharmaceutical Sciences, University at Buffalo, Buffalo, NY
| | - Sina Ghaemmaghami
- From the ‡University of Rochester Mass Spectrometry Resource Laboratory, Rochester, NY; .,§Department of Biology, University of Rochester, Rochester, NY
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Collective Cell Behaviour with Neighbour-Dependent Proliferation, Death and Directional Bias. Bull Math Biol 2016; 78:2277-2301. [DOI: 10.1007/s11538-016-0222-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 10/04/2016] [Indexed: 11/26/2022]
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Trosko JE, Chang CC. Potential Role of Intercellular Communication in the Rate-Limiting Step in Carcinogenesis. ACTA ACUST UNITED AC 2016. [DOI: 10.3109/10915818309140689] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In order to ascertain whether there might be a scientific basis for determining practical “thresholds” for “carcinogens,” the concepts of thresholds and carcinogens were examined in the context of some current ideas on cardnogenesis. The observation that cardnogenesis seems to involve the donal expansion of a pre-malignant cell through a series of pheno-typic changes was explained by the initiation/promotion model of cardnogenesis. Unrepaired DNA lesions, acting as substrates for mutations in dividing cells, were speculated to play a role in the initiation phase of cardnogenesis (and indirectly to the promotion phase if the lesions lead to significant cell killing, forcing “compensatory hyperplasia”). Inhibition of intercellular communication, either by cell removal, cell death, growth factors or chemical promoters, was speculated to allow the donal expansion of initiated cells to reach a “critical mass.” During that donal expansion of initiated cells, additional phenotypic changes were speculated to occur during cell replication by mutational and/or epigenetic events. Therefore, it was concluded, on the basis of this model, that conditions which prevented the inhibition of intercellular communication between normal cells and the initiated cell(s) contributed to the rate limiting step of cardnogenesis.Assuming the initiation and promotion model of cardnogenesis, the classical concepts of “thresholds” and “carcinogens” were viewed as grossly inadequate because they did not symbolically represent the known determinants of the complex carcinogenic process. Unless genetic, developmental stage, tissue, nutritional, stress, life style, as well as concurrent antagonists and/or synergists, factors are known, extrapolation about the potential carcinogenicity of a given chemical from molecular, in vitro or even in vivo experiments or epidemiological data would be extremely risky. It was concluded that, at this stage of our understanding of the mech-anism(s) of carcinogenesis, attempts to determine “thresholds” for “carcinogens” naively assume “carcinogens” are the single determinants for carcinogenesis, and that all chemicals which might influence the appearance of tumors act the same way.
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Affiliation(s)
- James E. Trosko
- Department of Pediatrics and Human Development Division of Human Genetics, Genetic Toxicology, Endocrinology and Oncology. Michigan State University
| | - Chia-cheng Chang
- Department of Pediatrics and Human Development Division of Human Genetics, Genetic Toxicology, Endocrinology and Oncology. Michigan State University
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22
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Occludin S471 Phosphorylation Contributes to Epithelial Monolayer Maturation. Mol Cell Biol 2016; 36:2051-66. [PMID: 27185880 DOI: 10.1128/mcb.00053-16] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 05/10/2016] [Indexed: 12/25/2022] Open
Abstract
Multiple organ systems require epithelial barriers for normal function, and barrier loss is a hallmark of diseases ranging from inflammation to epithelial cancers. However, the molecular processes regulating epithelial barrier maturation are not fully elucidated. After contact, epithelial cells undergo size-reductive proliferation and differentiate, creating a dense, highly ordered monolayer with high resistance barriers. We provide evidence that the tight junction protein occludin contributes to the regulation of epithelial cell maturation upon phosphorylation of S471 in its coiled-coil domain. Overexpression of a phosphoinhibitory occludin S471A mutant prevents size-reductive proliferation and subsequent tight junction maturation in a dominant manner. Inhibition of cell proliferation in cell-contacted but immature monolayers recapitulated this phenotype. A kinase screen identified G-protein-coupled receptor kinases (GRKs) targeting S471, and GRK inhibitors delayed epithelial packing and junction maturation. We conclude that occludin contributes to the regulation of size-reductive proliferation and epithelial cell maturation in a phosphorylation-dependent manner.
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23
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Fast calcium wave inhibits excessive apoptosis during epithelial wound healing. Cell Tissue Res 2016; 365:343-56. [PMID: 26987821 DOI: 10.1007/s00441-016-2388-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2015] [Accepted: 02/29/2016] [Indexed: 01/08/2023]
Abstract
Successful wound closure is mainly the result of two cellular processes: migration and proliferation. Apoptosis has also been suggested to play a role in the mechanisms of wound healing. The fast calcium wave (FCW), triggered immediately after a wound is produced, has been proposed to be involved in determining healing responses in epithelia. We have explored the effects of the reversible inhibition of FCW on the apoptotic and proliferative responses of healing bovine corneal endothelial (BCE) cells in culture. The most important findings of this study are that caspase-dependent apoptosis occurs during the healing process, that the amount of apoptosis has a linear dependence on the migrated distance, and that FCW inhibition greatly increases the apoptotic index. We have further been able to establish that FCW plays a role in the control of cell proliferation during BCE wound healing. These results indicate that one of the main roles of the wave is to inhibit an excessive apoptotic response of the healing migrating cells. This property might represent a basic mechanism to allow sufficient migration and proliferation of the healing cells to assure proper restitution of the injured tissue.
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Youssefi R, Tajik P, Movahedin M, Akbarinejad V. Enhancement in colonization of bovine spermatogonial stem cells following addition of knock-out serum replacement to culture medium. VETERINARY RESEARCH FORUM : AN INTERNATIONAL QUARTERLY JOURNAL 2016; 7:275-280. [PMID: 28144417 PMCID: PMC5251348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 09/07/2015] [Indexed: 11/24/2022]
Abstract
Enrichment of cell suspension with germ cells prior to injection into recipient seminiferous tubules is of importance in spermatogonial stem cells (SSCs) transplantation. Knock-out serum replacement (KSR) has been reported to enhance the proliferation of murine SSCs and human embryonic stem cells. The aim of the present study was to investigate the effect of KSR versus fetal bovine serum (FBS) and their interaction on colonization of bovine SSCs in vitro. When FBS (10%) was replaced with KSR (10%), a significant increase in the colonization of SSCs and the expression of Thy1, as marker for enrichment of SSCs, was observed. It was revealed that the lesser proliferative effect of FBS as well as the greater proliferative impact of KSR on SSCs colonization were not irreversible as cells having been cultured with FBS (10%) for three days with low colonization showed high rate of colonization in response to KSR (10%) and cells having been cultured with KSR (10%) with high colonization experienced low rate of colonization in response to FBS (10%). Further, it was shown that FBS did not contain factors inhibiting SSCs colonization and it simply lacked factors essential for SSCs proliferation because the combination of FBS (5%) and KSR (5%) resulted in even greater rate of colonization than did KSR (10%). In conclusion, the present study showed that addition of KSR to culture medium would significantly increase SSCs proliferation.
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Affiliation(s)
- Reza Youssefi
- Department of Theriogenology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - Parviz Tajik
- Department of Theriogenology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran,Correspondence: Parviz Tajik. DVM, DVSc ,Department of Theriogenology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran. E-mail:
| | - Mansoureh Movahedin
- Department of Anatomical Sciences, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Vahid Akbarinejad
- Young Researchers and Elites Club, Roudehen Branch, Islamic Azad University, Roudehen, Iran
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25
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Ma L, Liu X, Wang F, He X, Chen S, Li W. Different Donor Cell Culture Methods Can Influence the Developmental Ability of Cloned Sheep Embryos. PLoS One 2015; 10:e0135344. [PMID: 26291536 PMCID: PMC4546374 DOI: 10.1371/journal.pone.0135344] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 07/21/2015] [Indexed: 11/28/2022] Open
Abstract
It was proposed that arresting nuclear donor cells in G0/G1 phase facilitates the development of embryos that are derived from somatic cell nuclear transfer (SCNT). Full confluency or serum starvation is commonly used to arrest in vitro cultured somatic cells in G0/G1 phase. However, it is controversial as to whether these two methods have the same efficiency in arresting somatic cells in G0/G1 phase. Moreover, it is unclear whether the cloned embryos have comparable developmental ability after somatic cells are subjected to one of these methods and then used as nuclear donors in SCNT. In the present study, in vitro cultured sheep skin fibroblasts were divided into four groups: (1) cultured to 70–80% confluency (control group), (2) cultured to full confluency, (3) starved in low serum medium for 4 d, or (4) cultured to full confluency and then further starved for 4 d. Flow cytometry was used to assay the percentage of fibroblasts in G0/G1 phase, and cell counting was used to assay the viability of the fibroblasts. Then, real-time reverse transcription PCR was used to determine the levels of expression of several cell cycle-related genes. Subsequently, the four groups of fibroblasts were separately used as nuclear donors in SCNT, and the developmental ability and the quality of the cloned embryos were compared. The results showed that the percentage of fibroblasts in G0/G1 phase, the viability of fibroblasts, and the expression levels of cell cycle-related genes was different among the four groups of fibroblasts. Moreover, the quality of the cloned embryos was comparable after these four groups of fibroblasts were separately used as nuclear donors in SCNT. However, cloned embryos derived from fibroblasts that were cultured to full confluency combined with serum starvation had the highest developmental ability. The results of the present study indicate that there are synergistic effects of full confluency and serum starvation on arresting fibroblasts in G0/G1 phase, and the short-term treatment of nuclear donor cells with these two methods could improve the efficiency of SCNT.
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Affiliation(s)
- LiBing Ma
- School of Mathematics, Physics and Biological Engineering, Inner Mongolia University of Science & Technology, Baotou, Inner Mongolia, China
- * E-mail:
| | - XiYu Liu
- School of Mathematics, Physics and Biological Engineering, Inner Mongolia University of Science & Technology, Baotou, Inner Mongolia, China
| | - FengMei Wang
- Baotou Light Industry Vocational Technical College, Baotou, Inner Mongolia, China
| | - XiaoYing He
- School of Mathematics, Physics and Biological Engineering, Inner Mongolia University of Science & Technology, Baotou, Inner Mongolia, China
| | - Shan Chen
- School of Mathematics, Physics and Biological Engineering, Inner Mongolia University of Science & Technology, Baotou, Inner Mongolia, China
| | - WenDa Li
- School of Mathematics, Physics and Biological Engineering, Inner Mongolia University of Science & Technology, Baotou, Inner Mongolia, China
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26
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Brown L, Wan H. Desmoglein 3: a help or a hindrance in cancer progression? Cancers (Basel) 2015; 7:266-86. [PMID: 25629808 PMCID: PMC4381258 DOI: 10.3390/cancers7010266] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 01/09/2015] [Accepted: 01/16/2015] [Indexed: 02/07/2023] Open
Abstract
Desmoglein 3 is one of seven desmosomal cadherins that mediate cell-cell adhesion in desmosomes. Desmosomes are the intercellular junctional complexes that anchor the intermediate filaments of adjacent cells and confer strong cell adhesion thus are essential in the maintenance of tissue architecture and structural integrity. Like adherens junctions, desmosomes function as tumour suppressors and are down regulated in the process of epithelial-mesenchymal transition and in tumour cell invasion and metastasis. However, recently several studies have shown that various desmosomal components, including desmoglein 3, are up-regulated in cancer with increased levels of expression correlating with the clinical stage of malignancy, implicating their potentiality to serve as a diagnostic and prognostic marker. Furthermore, in vitro studies have demonstrated that overexpression of desmoglein 3 in cancer cell lines activates several signal pathways that have an impact on cell morphology, adhesion and locomotion. These additional signalling roles of desmoglein 3 may not be associated to its adhesive function in desmosomes but rather function outside of the junctions, acting as a key regulator in the control of actin based cellular processes. This review will discuss recent advances which support the role of desmoglein 3 in cancer progression.
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Affiliation(s)
- Louise Brown
- Queen Mary University of London, Barts and the London School of Medicine and Dentistry, Center for Clinical and Diagnostic Oral Sciences, Institute of Dentistry, Blizard Building, London E1 2AT, UK.
| | - Hong Wan
- Queen Mary University of London, Barts and the London School of Medicine and Dentistry, Center for Clinical and Diagnostic Oral Sciences, Institute of Dentistry, Blizard Building, London E1 2AT, UK.
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27
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Schlüter DK, Ramis-Conde I, Chaplain MAJ. Multi-scale modelling of the dynamics of cell colonies: insights into cell-adhesion forces and cancer invasion from in silico simulations. J R Soc Interface 2014; 12:rsif.2014.1080. [PMID: 25519994 PMCID: PMC4305411 DOI: 10.1098/rsif.2014.1080] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Studying the biophysical interactions between cells is crucial to understanding how normal tissue develops, how it is structured and also when malfunctions occur. Traditional experiments try to infer events at the tissue level after observing the behaviour of and interactions between individual cells. This approach assumes that cells behave in the same biophysical manner in isolated experiments as they do within colonies and tissues. In this paper, we develop a multi-scale multi-compartment mathematical model that accounts for the principal biophysical interactions and adhesion pathways not only at a cell-cell level but also at the level of cell colonies (in contrast to the traditional approach). Our results suggest that adhesion/separation forces between cells may be lower in cell colonies than traditional isolated single-cell experiments infer. As a consequence, isolated single-cell experiments may be insufficient to deduce important biological processes such as single-cell invasion after detachment from a solid tumour. The simulations further show that kinetic rates and cell biophysical characteristics such as pressure-related cell-cycle arrest have a major influence on cell colony patterns and can allow for the development of protrusive cellular structures as seen in invasive cancer cell lines independent of expression levels of pro-invasion molecules.
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Affiliation(s)
| | - Ignacio Ramis-Conde
- Department of Mathematics, Faculty of Education, Universidad de Castilla la Mancha, Cuenca, Spain
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29
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Tanaka S, Nakao K, Sekimoto T, Oka M, Yoneda Y. Cell density-dependent nuclear accumulation of ELK3 is involved in suppression of PAI-1 expression. Cell Struct Funct 2013; 38:145-54. [PMID: 23708702 DOI: 10.1247/csf.13007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Cell-cell contact regulates the proliferation and differentiation of non-transformed cells, e.g., NIH/3T3 cells show growth arrest at high cell density. However, only a few reports described the dynamic behavior of transcription factors involved in this process. In this study, we showed that the mRNA levels of plasminogen activator inhibitor type 1 (PAI-1) decreased drastically at high cell density, and that ELK3, a member of the Ets transcription factor family, repressed PAI-1 expression. We also demonstrated that while ELK3 was distributed evenly throughout the cell at low cell density, it accumulated in the nucleus at high cell density, and that binding of DNA by ELK3 at the A domain facilitated its nuclear accumulation. Furthermore, we found that ETS1, a PAI-1 activator, occupied the ELK3-binding site within the PAI-1 promoter at low cell density, while it was released at high cell density. These results suggest that at high cell density, the switching of binding of transcription factors from ETS1 to ELK3 occurs at a specific binding site of the PAI-1 promoter, leading to the cell-density dependent suppression of PAI-1 expression.
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Affiliation(s)
- Shu Tanaka
- Department of Frontier Biosciences, Graduate School of Frontier Biosciences, Osaka University, Yamada-oka, Suita, Osaka, Japan
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30
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McClatchey AI, Yap AS. Contact inhibition (of proliferation) redux. Curr Opin Cell Biol 2012; 24:685-94. [DOI: 10.1016/j.ceb.2012.06.009] [Citation(s) in RCA: 147] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 06/14/2012] [Accepted: 06/28/2012] [Indexed: 11/15/2022]
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Thoreen CC, Chantranupong L, Keys HR, Wang T, Gray NS, Sabatini DM. A unifying model for mTORC1-mediated regulation of mRNA translation. Nature 2012; 485:109-13. [PMID: 22552098 PMCID: PMC3347774 DOI: 10.1038/nature11083] [Citation(s) in RCA: 1069] [Impact Index Per Article: 89.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 03/29/2012] [Indexed: 02/07/2023]
Abstract
The mTOR Complex 1 (mTORC1) kinase nucleates a pathway that promotes cell growth and proliferation and is the target of rapamycin, a drug with many clinical uses1. mTORC1 regulates mRNA translation, but the overall translational program is poorly defined and no unifying model exists to explain how mTORC1 differentially controls the translation of specific mRNAs. Here we use high-resolution transcriptome-scale ribosome profiling to monitor translation in cells acutely treated with the mTOR inhibitor Torin1, which, unlike rapamycin, fully inhibits mTORC12. These data reveal a surprisingly simple view of the mRNA features and mechanisms that confer mTORC1-dependent translation control. The subset of mRNAs that are specifically regulated by mTORC1 consists almost entirely of transcripts with established 5′ terminal oligopyrimidine (TOP) motifs, or, like Hsp90ab1 and Ybx1, with previously unrecognized TOP or related TOP-like motifs that we identified. We find no evidence to support proposals that mTORC1 preferentially regulates mRNAs with increased 5′ UTR length or complexity3. mTORC1 phosphorylates a myriad of translational regulators, but how it controls TOP mRNA translation is unknown4. Remarkably, loss of just the well-characterized mTORC1 substrates, the 4E-BP family of translational repressors, is sufficient to render TOP and TOP-like mRNA translation resistant to Torin1. The 4E-BPs inhibit translation initiation by interfering with the interaction between the cap-binding protein eIF4E and eIF4G1. Loss of this interaction diminishes the capacity of eIF4E to bind TOP and TOP-like mRNAs much more than other mRNAs, explaining why mTOR inhibition selectively suppresses their translation. Our results clarify the translational program controlled by mTORC1 and identify 4E-BPs and eIF4G1 as its master effectors.
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Affiliation(s)
- Carson C Thoreen
- Department of Cancer Biology, Dana Farber Cancer Institute, 250 Longwood Avenue, Boston, Massachusetts 02115, USA
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Molecular Pathogenesis of Vestibular Schwannomas: Insights for the Development of Novel Medical Therapies. Otolaryngol Pol 2012; 66:84-95. [DOI: 10.1016/s0030-6657(12)70754-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Accepted: 02/13/2012] [Indexed: 11/21/2022]
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Jacob A, Oblinger J, Bush ML, Brendel V, Santarelli G, Chaudhury AR, Kulp S, La Perle KMD, Chen CS, Chang LS, Welling DB. Preclinical validation of AR42, a novel histone deacetylase inhibitor, as treatment for vestibular schwannomas. Laryngoscope 2011; 122:174-89. [PMID: 22109824 DOI: 10.1002/lary.22392] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Revised: 09/07/2011] [Accepted: 09/14/2011] [Indexed: 01/17/2023]
Abstract
OBJECTIVES/HYPOTHESIS Recent studies indicate that vestibular schwannomas (VSs) rely on phosphatidylinositol 3-kinase/AKT activation to promote cell proliferation and survival; therefore, targeting AKT may provide new therapeutic options. We have previously shown that AR42, a novel histone deacetylase inhibitor, potently suppresses VS growth in vitro at doses correlating with AKT inactivation. The objectives of the current study were translational: 1) to examine the end biologic effects of AR42 on tumor growth in vivo, 2) to validate AKT as its in vivo molecular target, 3) to determine whether AR42 penetrates the blood-brain barrier (BBB), and 4) to study the pharmacotoxicity profile of AR42. STUDY DESIGN In vivo mouse studies. METHODS AR42 was dosed orally in murine schwannoma allografts and human VS xenografts. Magnetic resonance imaging was used to quantify changes in tumor volume, and intracellular molecular targets were analyzed using immunohistochemistry. BBB penetration was assayed, and both blood-chemistry measurements and histology studies were used to evaluate toxicity. RESULTS Growth of schwannoma implants was dramatically decreased by AR42 at doses correlating with AKT dephosphorylation, cell cycle arrest, and apoptosis. AR42 penetrated the BBB, and wild-type mice fed AR42 for 6 months behaved normally and gained weight appropriately. Blood-chemistry studies and organ histology performed after 3 and 6 months of AR42 treatment demonstrated no clinically significant abnormalities. CONCLUSIONS AR42 suppresses schwannoma growth at doses correlating with AKT pathway inhibition. This orally bioavailable drug penetrates the BBB, is well tolerated, and represents a novel candidate for translation to human VS clinical trials.
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Affiliation(s)
- Abraham Jacob
- Department of Surgery, Division of Otolaryngology, University of Arizona, Tucson, Arizona 85724, USA.
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Bush ML, Oblinger J, Brendel V, Santarelli G, Huang J, Akhmametyeva EM, Burns SS, Wheeler J, Davis J, Yates CW, Chaudhury AR, Kulp S, Chen CS, Chang LS, Welling DB, Jacob A. AR42, a novel histone deacetylase inhibitor, as a potential therapy for vestibular schwannomas and meningiomas. Neuro Oncol 2011; 13:983-99. [PMID: 21778190 DOI: 10.1093/neuonc/nor072] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Neurofibromatosis type 2 (NF2) is an autosomal-dominant disease that results in the formation of bilateral vestibular schwannomas (VSs) and multiple meningiomas. Treatment options for NF2-associated tumors are limited, and to date, no medical therapies are FDA approved. The ideal chemotherapeutic agent would inhibit both VS and meningiomas simultaneously. The objectives of this study are (1) to test the efficacy of AR42, a novel histone deacetylase inhibitor, to inhibit VS and meningioma growth and (2) to investigate this drug's mechanisms of action. Primary cultures of human VS and meningioma cells were established. Nf2-deficient mouse schwannoma and benign human meningioma Ben-Men-1 cells were also cultured. Cells were treated with AR42, and the drug's effects on proliferation and the cell cycle were analyzed using a methanethiosulfonate assay and flow cytometry, respectively. Human phospho-kinase arrays and Western blots were used to evaluate the effects of AR42 on intracellular signaling. The in vivo efficacy of AR42 was investigated using schwannoma xenografts. Tumor volumes were quantified using high-field, volumetric MRI, and molecular target analysis was performed using immunohistochemistry. AR42 inhibited the growth of primary human VS and Nf2-deficient mouse schwannoma cells with a half maximal inhibitory concentration (IC(50)) of 500 nM and 250-350 nM, respectively. AR42 also inhibited primary meningioma cells and the benign meningioma cell line, Ben-Men-1, with IC(50) values of 1.5 µM and 1.0 µM, respectively. AR42 treatment induced cell-cycle arrest at G(2) and apoptosis in both VS and meningioma cells. Also, AR42 exposure decreased phosphorylated Akt in schwannoma and meningioma cells. In vivo treatment with AR42 inhibited the growth of schwannoma xenografts, induced apoptosis, and decreased Akt activation. The potent growth inhibitory activity of AR42 in schwannoma and meningioma cells suggests that AR42 should be further evaluated as a potential treatment for NF2-associated tumors.
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Affiliation(s)
- Matthew L Bush
- Department of Otolaryngology–Head and Neck Surgery, The Ohio State University, Columbus, OH 43212, USA
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E-cadherin mediates contact inhibition of proliferation through Hippo signaling-pathway components. Proc Natl Acad Sci U S A 2011; 108:11930-5. [PMID: 21730131 DOI: 10.1073/pnas.1103345108] [Citation(s) in RCA: 513] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Contact inhibition of cell growth is essential for embryonic development and maintenance of tissue architecture in adult organisms, and the growth of tumors is characterized by a loss of contact inhibition of proliferation. The recently identified Hippo signaling pathway has been implicated in contact inhibition of proliferation as well as organ size control. The modulation of the phosphorylation and nuclear localization of Yes-associated protein (YAP) by the highly conserved kinase cascade of the Hippo signaling pathway has been intensively studied. However, cell-surface receptors regulating the Hippo signaling pathway in mammals are not well understood. In this study, we show that Hippo signaling pathway components are required for E-cadherin-dependent contact inhibition of proliferation. Knockdown of the Hippo signaling components or overexpression of YAP inhibits the decrease in cell proliferation caused by E-cadherin homophilic binding at the cell surface, independent of other cell-cell interactions. We also demonstrate that the E-cadherin/catenin complex functions as an upstream regulator of the Hippo signaling pathway in mammalian cells. Expression of E-cadherin in MDA-MB-231 cells restores the density-dependent regulation of YAP nuclear exclusion. Knockdown of β-catenin in densely cultured MCF10A cells, which mainly depletes E-cadherin-bound β-catenin, induces a decrease in the phosphorylation of S127 residue of YAP and its nuclear accumulation. Moreover, E-cadherin homophilic binding independent of other cell interactions is sufficient to control the subcellular localization of YAP. Therefore, Our results indicate that, in addition to its role in cell-cell adhesion, E-cadherin-mediated cell-cell contact directly regulates the Hippo signaling pathway to control cell proliferation.
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Noda N, Honma S, Ohmiya Y. Hes1 is required for contact inhibition of cell proliferation in 3T3-L1 preadipocytes. Genes Cells 2011; 16:704-13. [PMID: 21481105 DOI: 10.1111/j.1365-2443.2011.01518.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cell-cell contact causes the growth arrest of cells in culture, which is referred to as contact inhibition of cell proliferation. Notch signaling is involved in the growth arrest of cells represented by contact inhibition of cell proliferation. The Notch effector, Hes1 (Hairy and enhancer of split 1), promotes or inhibits cell proliferation by repressing the expression of cyclin-dependent kinase inhibitors. However, it is still unclear whether Hes1 is involved in the mechanisms responsible for contact inhibition of cell proliferation. Here, we examined the involvement of Hes1 in contact inhibition of cell proliferation using a γ-secretase inhibitor and a stable 3T3-L1 preadipocyte cell line expressing Hes1-shRNA as a model cell. The cell cycle was not arrested in Hes1-knockdown cells even after the cells reached confluence. Reduced Hes1 levels failed to repress the expression of E2F-1, a transcription factor required for the progression of the cell cycle. The expression of Myc, cyclin E1, and cyclin A2 in E2F-1 target genes was also higher in Hes1-knockdown cells compared with the negative control. These results suggest that Hes1 plays essential roles in contact inhibition of cell proliferation in 3T3-L1 cells by repressing E2F-1 expression.
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Affiliation(s)
- Natsumi Noda
- Department of Physiology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan
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Levine EM, Burleigh IG, Boone CW, Eagle H. An altered pattern of RNA synthesis in serially propagated human diploid cells. Proc Natl Acad Sci U S A 2010; 57:431-8. [PMID: 16591488 PMCID: PMC335524 DOI: 10.1073/pnas.57.2.431] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- E M Levine
- DEPARTMENT OF CELL BIOLOGY, ALBERT EINSTEIN COLLEGE OF MEDICINE, BRONX, NEW YORK
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Borek C, Sachs L. The difference in contact inhibition of cell replication between normal cells and cells transformed by different carcinogens. Proc Natl Acad Sci U S A 2010; 56:1705-11. [PMID: 16591408 PMCID: PMC220159 DOI: 10.1073/pnas.56.6.1705] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- C Borek
- SECTION OF GENETICS, WEIZMANN INSTITUTE OF SCIENCE, REHOVOTH, ISRAEL
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Sieff CA, Yang J, Merida-Long LB, Lodish HF. Pathogenesis of the erythroid failure in Diamond Blackfan anaemia. Br J Haematol 2009; 148:611-22. [PMID: 19958353 DOI: 10.1111/j.1365-2141.2009.07993.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Diamond Blackfan anaemia (DBA) is a severe congenital failure of erythropoiesis. Despite mutations in one of several ribosome protein genes, including RPS19, the cause of the erythroid specificity is still a mystery. We hypothesized that, because the chromatin of late erythroid cells becomes condensed and transcriptionally inactive prior to enucleation, the rapidly proliferating immature cells require very high ribosome synthetic rates. RNA biogenesis was measured in primary mouse fetal liver erythroid progenitor cells; during the first 24 h, cell number increased three to fourfold while, remarkably, RNA content increased sixfold, suggesting an accumulation of an excess of ribosomes during early erythropoiesis. Retrovirus infected siRNA RPS19 knockdown cells showed reduced proliferation but normal differentiation, and cell cycle analysis showed a G1/S phase delay. p53 protein was increased in the knockdown cells, and the mRNA level for p21, a transcriptional target of p53, was increased. Furthermore, we show that RPS19 knockdown decreased MYB protein, and Kit mRNA was reduced, as was the amount of cell surface KIT protein. Thus, in this small hairpin RNA murine model of DBA, RPS19 insufficient erythroid cells may proliferate poorly because of p53-mediated cell cycle arrest, and also because of decreased expression of the key erythroid signalling protein KIT.
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Affiliation(s)
- Colin A Sieff
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA.
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40
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Cell density-dependent inhibition of epidermal growth factor receptor signaling by p38alpha mitogen-activated protein kinase via Sprouty2 downregulation. Mol Cell Biol 2009; 29:3332-43. [PMID: 19364817 DOI: 10.1128/mcb.01955-08] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Contact inhibition is a fundamental process in multicellular organisms aimed at inhibiting proliferation at high cellular densities through poorly characterized intracellular signals, despite availability of growth factors. We have previously identified the protein kinase p38alpha as a novel regulator of contact inhibition, as p38alpha is activated upon cell-cell contacts and p38alpha-deficient cells are impaired in both confluence-induced proliferation arrest and p27(Kip1) accumulation. Here, we establish that p27(Kip1) plays a key role downstream of p38alpha to arrest proliferation at high cellular densities. Surprisingly, p38alpha does not directly regulate p27(Kip1) expression levels but leads indirectly to confluent upregulation of p27(Kip1) and cell cycle arrest via the inhibition of mitogenic signals originating from the epidermal growth factor receptor (EGFR). Hence, confluent activation of p38alpha uncouples cell proliferation from mitogenic stimulation by inducing EGFR degradation through downregulation of the EGFR-stabilizing protein Sprouty2 (Spry2). Accordingly, confluent p38alpha-deficient cells fail to downregulate Spry2, providing them in turn with sustained EGFR signaling that facilitates cell overgrowth and oncogenic transformation. Our results provide novel mechanistic insight into the role of p38alpha as a sensor of cell density, which induces confluent cell cycle arrest via the Spry2-EGFR-p27(Kip1) network.
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Abstract
This review explores possible mechanisms by which the neurofibromatosis type-2 tumour suppressor Merlin regulates contact-dependent inhibition of proliferation. Starting from an evolutionary perspective, the concurrent emergence of intercellular contacts and proliferation control in multicellular organisms is first considered. Following a brief survey of the molecular and subcellular milieus in which merlin performs its function, the importance of different cellular and biological contexts in defining the function of merlin is discussed. Finally, an integrated model for merlin and the Ezrin, Radixin, and Moesin (ERM) proteins functioning in the regulation of cellular interfaces is proposed.
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Pennington SR, Foster BJ, Hawley SR, Jenkins RE, Zolle O, White MRH, McNamee CJ, Sheterline P, Simpson AWM. Cell shape-dependent Control of Ca2+ influx and cell cycle progression in Swiss 3T3 fibroblasts. J Biol Chem 2007; 282:32112-20. [PMID: 17711856 DOI: 10.1074/jbc.m705067200] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The ability of adherent cells such as fibroblasts to enter the cell cycle and progress to S phase is strictly dependent on the extent to which individual cells can attach to and spread on a substratum. Here we have used microengineered adhesive islands of 22 and 45 mum diameter surrounded by a nonadhesive substratum of polyhydroxyl methacrylate to accurately control the extent to which individual Swiss 3T3 fibroblasts may spread. The effect of cell shape on mitogen-evoked Ca2+ signaling events that accompany entry into the cell cycle was investigated. In unrestricted cells, the mitogens bombesin and fetal calf serum evoked a typical biphasic change in the cytoplasmic free Ca2+ concentration. However, when the spreading of individual cells was restricted, such that progression to S phase was substantially reduced, both bombesin and fetal calf serum caused a rapid transient rise in the cytoplasmic free Ca2+ concentration but failed to elicit the normal sustained influx of Ca2+ that follows Ca2+ release. As expected, restricting cell spreading led to the loss of actin stress fibers and the formation of a ring of cortical actin. Restricting cell shape did not appear to influence mitogen-receptor interactions, nor did it influence the presence of focal adhesions. Because Ca2+ signaling is an essential component of mitogen responses, these findings implicate Ca2+ influx as a necessary component of cell shape-dependent control of the cell cycle.
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Affiliation(s)
- Stephen R Pennington
- Department of Human Anatomy and Cell Biology, School of Biomedical Sciences, University of Liverpool, Sherrington Buildings, Ashton Street, Liverpool L69 3GE, United Kingdom
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Rubin H. Central roles of Mg2+ and MgATP2- in the regulation of protein synthesis and cell proliferation: significance for neoplastic transformation. Adv Cancer Res 2005; 93:1-58. [PMID: 15797443 DOI: 10.1016/s0065-230x(05)93001-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Growth factors are polypeptides that combine with specific membrane receptors on animal cells to stimulate proliferation, but they also stimulate glucose transport, uridine phosphorylation, intermediary metabolism, protein synthesis, and other processes of the coordinate response. There are a variety of nonspecific surface action treatments which stimulate the same set of reactions as the growth factors do, of which protein synthesis is most directly related to the onset of DNA synthesis. Mg(2+) is required for a very wide range of cellular reactions, including all phosphoryl transfers, and its deprivation inhibits all components of the coordinate response that have so far been tested. Growth factors raise the level of free Mg(2+) closer to the optimum for the initiation of protein synthesis. The resulting increase in protein synthesis accelerates progression through G1 to the onset of DNA synthesis and mitosis. None of the other 3 major cellular cations are similarly involved in growth regulation, although internal pH may play an auxiliary role. Almost 10(5) externally bound divalent cations are displaced from membranes for every attached insulin molecule, implying a conformational membrane change that releases enough Mg(2+) from the internal surface of the plasma membrane to account for the increase in free cytosolic Mg(2+). It is proposed that mTOR, the central control point for protein synthesis of the PI 3-K kinase cascade stimulated by insulin, is regulated by MgATP(2-) which varies directly with cytosolic Mg(2+). Other elements of the coordinate response to growth factors such as the increased transport of glucose and phosphorylation of uridine are also dependent upon an increase of Mg(2+). Deprivation of Mg(2+) in neoplastically transformed cultures normalizes their appearance and growth behavior and raises their abnormally low Ca(2+) concentration. Tight packing of the transformed cells at very high saturation density confers the same normalizing effects, which are retained for a few days after subculture at low density. The results suggest that the activity of Mg(2+) within the cell is a central regulator of normal cell growth, and the loss of its membrane-mediated control can account for the neoplastic phenotype.
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Affiliation(s)
- Harry Rubin
- Department of Molecular and Cell Biology, Life Sciences Addition, University of California Berkeley, 94720-3200, USA
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45
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Abstract
The quantitative study of regulation of cell growth and proliferation began with the development of the technique for monolayer culture of vertebrate cells in the late 1960s. The basic parameters were defined in the early physiological studies, which continued through the next decade. These included specific and non-specific growth factors and the requirement for continuous exposure to such factors through most of the G1 period for progression to S. In the course of this work, the diversity of biochemical responses and the critical role of increased protein synthesis and accumulation for the onset of DNA synthesis were elucidated. In particular, a central role of free cytosolic Mg2+ in direct regulation of protein synthesis and in ancillary processes as a response to membrane perturbation was established. Eventually, the physiological era was superseded by the molecular era beginning in the 1980s. This work focussed on specific receptors for growth factors that entrained a protein kinase cascade, which terminated in a higher frequency of initiation of protein synthesis. However, the molecular studies virtually ignored the key results of the physiological era. Recent studies of the penultimate molecular steps in the regulatory pathway of protein synthesis, however, have supported a model of growth regulation involving membrane perturbation and MgATP2- concentration, results that integrate the findings of the physiological and molecular eras. The resulting relatively simple "membrane, magnesium mitosis" (MMM) model of proliferation control can explain the seeming paradox of the variety of specific and non-specific growth-enhancing treatments that are mediated by the plasma membrane and which bring about a shared, complex but coordinated growth response that drives cell proliferation.
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Affiliation(s)
- Harry Rubin
- Department of Molecular and Cell Biology, Life Sciences Addition, University of California, Berkeley, CA 94720-3200, USA.
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46
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Thomas EK, Nakamura M, Wienke D, Isacke CM, Pozzi A, Liang P. Endo180 binds to the C-terminal region of type I collagen. J Biol Chem 2005; 280:22596-605. [PMID: 15817460 DOI: 10.1074/jbc.m501155200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Type I collagen is a fibril-forming heterotrimer composed of two alpha1 and one alpha2 chains and plays a crucial role in cell-matrix adhesion and cell differentiation. Through a comprehensive differential display screening of oncogenic ras target genes, we have shown that the alpha1 chain of type I collagen (col1a1) is markedly down-regulated by the ras oncogene through the mitogen-activated protein kinase pathway. Although ras-transformed cells are no longer able to produce and secrete endogenous collagen, they can still adhere to exogenous collagen, suggesting that the cells express a collagen binding factor(s) on the cell surface. When the region of col1a1 encompassing the C-terminal glycine repeat and C-prodomain (amino acids 1000-1453) was affinity-labeled with human placental alkaline phosphatase, the secreted trimeric fusion protein could bind to the surface of Ras-transformed cells. Using biochemical purification followed by matrix-assisted laser desorption/ionization mass spectrometry analysis, we identified this collagen binding factor as Endo180 (uPARAP, CD280), a member of the mannose receptor family. Ectopic expression of Endo180 in CosE5 cells followed by in situ staining and quantitative binding assays confirmed that Endo180 indeed recognizes and binds to placental alkaline phosphatase. The interaction between Endo180 and the C-terminal region of type I collagen appears to play an important role in cell-matrix adhesion.
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MESH Headings
- Alkaline Phosphatase/metabolism
- Animals
- Blotting, Northern
- Blotting, Western
- COS Cells
- Cell Adhesion
- Cell Differentiation
- Cell Line
- Cell Separation
- Collagen/metabolism
- Collagen/pharmacology
- Collagen Type I/chemistry
- Collagen Type I/metabolism
- Collagen Type I, alpha 1 Chain
- DNA, Complementary/metabolism
- Down-Regulation
- Drug Combinations
- Electrophoresis, Polyacrylamide Gel
- Enzyme Inhibitors/pharmacology
- Fibroblasts/metabolism
- Fibronectins/chemistry
- Flow Cytometry
- Gene Expression Profiling
- Glycine/chemistry
- Humans
- Laminin/pharmacology
- MAP Kinase Signaling System
- Models, Molecular
- Molecular Sequence Data
- Peptides/chemistry
- Phenotype
- Placenta/enzymology
- Protein Binding
- Protein Structure, Tertiary
- Proteoglycans/pharmacology
- RNA Interference
- RNA, Small Interfering/metabolism
- Rats
- Receptors, Mitogen/chemistry
- Receptors, Mitogen/metabolism
- Recombinant Fusion Proteins/chemistry
- Recombinant Fusion Proteins/metabolism
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Time Factors
- Transfection
- ras Proteins/metabolism
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Affiliation(s)
- Emily K Thomas
- Vanderbilt-Ingram Cancer Center, Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
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47
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Rappaport C. Review-progress in concept and practice of growing anchorage-dependent mammalian cells in three dimension. In Vitro Cell Dev Biol Anim 2003; 39:187-92. [PMID: 12880369 DOI: 10.1290/1543-706x(2003)039<0187:ricapo>2.0.co;2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2003] [Revised: 07/06/2003] [Accepted: 07/24/2003] [Indexed: 12/18/2022]
Abstract
Tissue culture has played a major role in the rapid advances made in medical science in the past 50 yr. The full potential of the technique, however, is limited by the fact that growth of cells is usually restricted to a monolayer accompanied by major decreases in many of their tissue-specific functions. This has been shown to be due, in large part, to the inadequate oxygenation of cells growing in tissue culture dishes. Studies that show that the high charge density and rigidity of the plastic and glass surfaces used for culture are also major factors limiting growth of cells to a monolayer, are reviewed. A new culture system has been developed in which cells are grown on substrata made using perfluorocarbons (PFCs) coated with collagen type 1 and other adhesive factors. Perfluorocarbons have a much higher solubility for oxygen than water and have been used as oxygen delivery systems to protect cells from hypoxia. These new PFC-based substrata can provide both the optimal level of oxygen cells need to maintain differentiated functions and the flexible and weaker type of adhesion that allows cells to round up, interact with each other, and when provided with adequate nutritional support, to grow in three dimension.
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Affiliation(s)
- Catherine Rappaport
- Department of Chemical and Fuels Engineering, University of Utah, Salt Lake City, Utah 84112-9203, USA.
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Sigoillot FD, Berkowski JA, Sigoillot SM, Kotsis DH, Guy HI. Cell cycle-dependent regulation of pyrimidine biosynthesis. J Biol Chem 2003; 278:3403-9. [PMID: 12438317 DOI: 10.1074/jbc.m211078200] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
De novo pyrimidine biosynthesis is activated in proliferating cells in response to an increased demand for nucleotides needed for DNA synthesis. The pyrimidine biosynthetic pathway in baby hamster kidney cells, synchronized by serum deprivation, was found to be up-regulated 1.9-fold during S phase and subsequently down-regulated as the cells progressed through the cycle. The nucleotide pools were depleted by serum starvation and were not replenished during the first round of cell division, suggesting that the rate of utilization of the newly synthesized nucleotides closely matched their rate of formation. The activation and subsequent down-regulation of the pathway can be attributed to altered allosteric regulation of the carbamoyl-phosphate synthetase activity of CAD (carbamoyl-phosphate synthetase-aspartate carbamoyltransferase-dihydroorotase), a multifunctional protein that initiates mammalian pyrimidine biosynthesis. As the culture approached S-phase there was an increased sensitivity to the allosteric activator, 5-phosphoribosyl-1-pyrophosphate, and a loss of UTP inhibition, changes that were reversed when cells emerged from S phase. The allosteric regulation of CAD is known to be modulated by MAP kinase (MAPK) and protein kinase A (PKA)-mediated phosphorylations as well as by autophosphorylation. CAD was found to be fully autophosphorylated in the synchronized cells, but the level remained invariant throughout the cycle. Although the MAPK activity increased early in G(1), the phosphorylation of the CAD MAPK site was delayed until just before the onset of S phase, probably due to antagonistic phosphorylation by PKA that persisted until late G(1). Once activated, pyrimidine biosynthesis remained elevated until rephosphorylation of CAD by PKA and dephosphorylation of the CAD MAPK site late in S phase. Thus, the cell cycle-dependent regulation of pyrimidine biosynthesis results from the sequential phosphorylation and dephosphorylation of CAD under the control of two important signaling cascades.
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Affiliation(s)
- Frederic D Sigoillot
- Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, Michigan 48201,USA
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49
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Sigoillot FD, Evans DR, Guy HI. Growth-dependent regulation of mammalian pyrimidine biosynthesis by the protein kinase A and MAPK signaling cascades. J Biol Chem 2002; 277:15745-51. [PMID: 11872754 DOI: 10.1074/jbc.m201112200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The carbamoyl phosphate synthetase domain of the multifunctional protein CAD catalyzes the initial, rate-limiting step in mammalian de novo pyrimidine biosynthesis. In addition to allosteric regulation by the inhibitor UTP and the activator PRPP, the carbamoyl phosphate synthetase activity is controlled by mitogen-activated protein kinase (MAPK)- and protein kinase A (PKA)-mediated phosphorylation. MAPK phosphorylation, both in vivo and in vitro, increases sensitivity to PRPP and decreases sensitivity to the inhibitor UTP, whereas PKA phosphorylation reduces the response to both allosteric effectors. To elucidate the factors responsible for growth state-dependent regulation of pyrimidine biosynthesis, the activity of the de novo pyrimidine pathway, the MAPK and PKA activities, the phosphorylation state, and the allosteric regulation of CAD were measured as a function of growth state. As cells entered the exponential growth phase, there was an 8-fold increase in pyrimidine biosynthesis that was accompanied by a 40-fold increase in MAPK activity and a 4-fold increase in CAD threonine phosphorylation. PRPP activation increased to 21-fold, and UTP became a modest activator. These changes were reversed when the cultures approach confluence and growth ceases. Moreover, CAD phosphoserine, a measure of PKA phosphorylation, increased 2-fold in confluent cells. These results are consistent with the activation of CAD by MAPK during periods of rapid growth and its down-regulation in confluent cells associated with decreased MAPK phosphorylation and a concomitant increase in PKA phosphorylation. A scheme is proposed that could account for growth-dependent regulation of pyrimidine biosynthesis based on the sequential action of MAPK and PKA on the carbamoyl phosphate synthetase activity of CAD.
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Affiliation(s)
- Frederic D Sigoillot
- Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA
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50
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Trosko JE, Chang CC. Mechanism of up-regulated gap junctional intercellular communication during chemoprevention and chemotherapy of cancer. Mutat Res 2001; 480-481:219-29. [PMID: 11506816 DOI: 10.1016/s0027-5107(01)00181-6] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
To develop a strategy for efficacious intervention in order to prevent or treat various cancers, one must understand the basic mechanism(s) by which various anticancer dietary factors prevent or reverse the tumor promotion or progression phases. Carcinogenesis is a multistage, multimechanism process, involving the irreversible alteration of a stem cell (the "initiation" phase), followed by the clonal proliferation of the initiated stem cell (the "promotion" phase), from which the acquisition of the invasive and metastatic phenotypes are generated (the "progression" phase). While intervention to prevent or treat cancer could occur at each step, the objective of this presentation will focus on the rate limiting step, the promotion phase.Gap junctional intercellular communication (GJIC) has been hypothesized to regulate growth control, differentiation and apoptosis. Most normal, contact-inhibited cells have functional GJIC, while most, if not all, tumor cells have dysfunctional homologous or heterologous GJIC. Cancer cells are characterized by the lack of growth control, by the inability to terminally differentiate and by resistance to apoptosis. Chemical tumor promoters (phorbol esters, DDT, phenobarbital, unsaturated fatty acids, saccharin, etc.) inhibit GJIC in a reversible fashion and at doses above particular chemical thresholds. Various oncogenes (e.g. ras, raf, neu, src, mos) down-regulate GJIC while several tumor suppressor genes can up-regulate GJIC. Antitumor promoters (retinoids, carotenoids, green tea components) and antioncogene drugs (i.e. lovastatin) can up-regulate GJIC. Transfection of gap junction genes ("connexins") into GJIC-deficient tumor cells can restore GJIC, growth control and reduce tumorigenicity. On the other hand, antisense gap junction genes can convert the phenotype of a non-tumorigenic cell to that of a tumorigenic one. Recently, a specific connexin knockout mouse was shown to have a higher frequency of spontaneous and induced liver cancers. Evidence from these studies clearly suggests that dietary factors can modulate GJIC by inducing various signal transducing systems. The modulation can either down-regulate GJIC and lead to tumor promotion or it can up-regulate GJIC and lead to suppression of the initiated cells. Multiple mechanisms of up- or down-regulation of GJIC exist, as well as multiple types of pre-malignant and malignant tumor cells that are unable able to have functional GJIC. GJIC can be down-regulated by mutations and by epigenetic means. Alteration of gene expression at the transcriptional, translational or post-translational levels would require specific dietary prevention or treatment of cancer. In conclusion, if dietary prevention or treatment of cancer is to occur, it must ameliorate the growth-stimulatory effects, above threshold levels, of chemicals, growth factors or hormones, that trigger various mitogenic/antiapoptotic signal transducing systems that block GJIC.
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Affiliation(s)
- J E Trosko
- Department of Pediatrics and Human Development, Institute of Environmental Toxicology, 246 National Food Safety Toxicology Center, Michigan State University, B-240 Life Sciences Bldg., East Lansing, MI 48824, USA.
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