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Manna S, Kirtana R, Roy A, Baral T, Patra SK. Mechanisms of hedgehog, calcium and retinoic acid signalling pathway inhibitors: Plausible modes of action along the MLL-EZH2-p53 axis in cellular growth control. Arch Biochem Biophys 2023; 742:109600. [PMID: 37142078 DOI: 10.1016/j.abb.2023.109600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 04/04/2023] [Accepted: 04/05/2023] [Indexed: 05/06/2023]
Abstract
Understanding the molecular mechanism(s) of small compounds in cellular growth control are essential for using those against the disease(s). Oral cancers exhibit a very high mortality rate due to higher metastatic potential. Aberrant EGFR, RAR, HH signalling, enhanced [Ca2+] and oxidative stress are some of the important characteristics of oral cancer. So, we target these for our study. Herein, we tested the effect of fendiline hydrochloride (FH) as an LTCC Ca2+-channel inhibitor, erismodegib (a SMO inhibitor of HH-signalling) and all-trans retinoic acid (RA) inducer of RAR signalling that causes cellular differentiation. OCT4 activating compound (OAC1) counters differentiation and induces stemness properties. Cytosine β-D arabinofuranoside (Cyto-BDA), a DNA replication inhibitor was used to reduce high proliferative capacity. Treatment of FaDu cells with OAC1, Cyto-BDA and FH increase G0/G1 population by 3%, 20% and 7% respectively, and lead to reduction of cyclin D1, CDK4/6 levels. Erismodegib arrests the cells in S-phase with reduced cyclin-E1&A1 levels, whereas RA-treatment causes G2/M phase arrest with reduced cyclin-B1. There was a decrease in the expression of EGFR and mesenchymal markers, Snail/Slug/Vim/Zeb/Twist, and increased E-cadherin expression in all the drug treatments, indicating a reduction in proliferative signal and EMT. Enhanced MLL2 (Mll4) and reduced EZH2 expression associated overexpression of p53 and p21 were traced out. We conclude that these drugs impact expression of epigenetic modifiers by modulating signalling pathways and the epigenetic modifiers then controls the expression of cell cycle control genes, including p53 and p21.
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Affiliation(s)
- Soumen Manna
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, Odisha, 769008, India
| | - R Kirtana
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, Odisha, 769008, India
| | - Ankan Roy
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, Odisha, 769008, India
| | - Tirthankar Baral
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, Odisha, 769008, India
| | - Samir Kumar Patra
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, Odisha, 769008, India.
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Rowton M, Perez-Cervantes C, Hur S, Jacobs-Li J, Lu E, Deng N, Guzzetta A, Hoffmann AD, Stocker M, Steimle JD, Lazarevic S, Oubaha S, Yang XH, Kim C, Yu S, Eckart H, Koska M, Hanson E, Chan SSK, Garry DJ, Kyba M, Basu A, Ikegami K, Pott S, Moskowitz IP. Hedgehog signaling activates a mammalian heterochronic gene regulatory network controlling differentiation timing across lineages. Dev Cell 2022; 57:2181-2203.e9. [PMID: 36108627 PMCID: PMC10506397 DOI: 10.1016/j.devcel.2022.08.009] [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: 01/14/2022] [Revised: 06/24/2022] [Accepted: 08/22/2022] [Indexed: 11/18/2022]
Abstract
Many developmental signaling pathways have been implicated in lineage-specific differentiation; however, mechanisms that explicitly control differentiation timing remain poorly defined in mammals. We report that murine Hedgehog signaling is a heterochronic pathway that determines the timing of progenitor differentiation. Hedgehog activity was necessary to prevent premature differentiation of second heart field (SHF) cardiac progenitors in mouse embryos, and the Hedgehog transcription factor GLI1 was sufficient to delay differentiation of cardiac progenitors in vitro. GLI1 directly activated a de novo progenitor-specific network in vitro, akin to that of SHF progenitors in vivo, which prevented the onset of the cardiac differentiation program. A Hedgehog signaling-dependent active-to-repressive GLI transition functioned as a differentiation timer, restricting the progenitor network to the SHF. GLI1 expression was associated with progenitor status across germ layers, and it delayed the differentiation of neural progenitors in vitro, suggesting a broad role for Hedgehog signaling as a heterochronic pathway.
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Affiliation(s)
- Megan Rowton
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Carlos Perez-Cervantes
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Suzy Hur
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Jessica Jacobs-Li
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Emery Lu
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Nikita Deng
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Alexander Guzzetta
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Andrew D Hoffmann
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Matthew Stocker
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Jeffrey D Steimle
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Sonja Lazarevic
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Sophie Oubaha
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Xinan H Yang
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Chul Kim
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Shuhan Yu
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Heather Eckart
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Mervenaz Koska
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Erika Hanson
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Sunny S K Chan
- Lillehei Heart Institute, University of Minnesota, Minneapolis, MN 55455, USA; Department of Pediatrics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Daniel J Garry
- Lillehei Heart Institute, University of Minnesota, Minneapolis, MN 55455, USA; Department of Pediatrics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Michael Kyba
- Lillehei Heart Institute, University of Minnesota, Minneapolis, MN 55455, USA; Department of Pediatrics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Anindita Basu
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Kohta Ikegami
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Sebastian Pott
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Ivan P Moskowitz
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA.
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3
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Carrillo C, Ravi V, Tiwari S, Chernoff EA, Belecky-Adams TL. TAK1 inhibition increases proliferation and differentiation of chick retinal cells. Front Cell Dev Biol 2022; 10:698233. [PMID: 36176271 PMCID: PMC9513612 DOI: 10.3389/fcell.2022.698233] [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: 04/21/2021] [Accepted: 08/24/2022] [Indexed: 12/15/2022] Open
Abstract
The factors necessary for the differentiation of cell types within the retina are incompletely understood. The transforming growth factor beta (TGF-β) superfamily, including TGF-β1 and 2, the bone morphogenetic proteins, and the activins have all been implicated in differentiation; however, the mechanisms by which these factors affect differentiation are only partially understood. The studies herein focus on a potential role for transforming growth factor β-activated kinase 1 (TAK1), a hub kinase that lies at the intersection of multiple signaling pathways, in the differentiation of cell types within the chick retina. Previous studies have focused predominantly on the role this kinase plays in the inflammation process and axonal growth. TAK1 is downstream of multiple signaling pathways that are critical to development of the central nervous system, including transforming growth factor β (TGFβ), bone morphogenetic proteins (BMPs), and activins. The present study indicates that activated TAK1 is found throughout the developing retina; however, it is localized at higher levels in dividing and differentiating cells. Further, ex ovo retinal studies using TAK1 inhibitor 5Z-7-oxozeaenol increased both progenitor and differentiating cell populations, accompanied by a substantial increase in proliferation and a smaller increase in cell death. These results indicate a unique role for TAK1 in differentiating and proliferating retinal cells.
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Affiliation(s)
| | | | | | | | - Teri L. Belecky-Adams
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
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4
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Li LX, Li X. Epigenetically Mediated Ciliogenesis and Cell Cycle Regulation, and Their Translational Potential. Cells 2021; 10:cells10071662. [PMID: 34359832 PMCID: PMC8307023 DOI: 10.3390/cells10071662] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/24/2021] [Accepted: 06/29/2021] [Indexed: 12/13/2022] Open
Abstract
Primary cilia biogenesis has been closely associated with cell cycle progression. Cilia assemble when cells exit the cell cycle and enter a quiescent stage at the post-mitosis phase, and disassemble before cells re-enter a new cell cycle. Studies have focused on how the cell cycle coordinates with the cilia assembly/disassembly process, and whether and how cilia biogenesis affects the cell cycle. Appropriate regulation of the functions and/or expressions of ciliary and cell-cycle-associated proteins is pivotal to maintaining bodily homeostasis. Epigenetic mechanisms, including DNA methylation and histone/chromatin modifications, are involved in the regulation of cell cycle progression and cilia biogenesis. In this review, first, we discuss how epigenetic mechanisms regulate cell cycle progression and cilia biogenesis through the regulation of DNA methylation and chromatin structures, to either promote or repress the transcription of genes associated with those processes and the modification of cytoskeleton network, including microtubule and actin. Next, we discuss the crosstalk between the cell cycle and ciliogenesis, and the involvement of epigenetic regulators in this process. In addition, we discuss cilia-dependent signaling pathways in cell cycle regulation. Understanding the mechanisms of how epigenetic regulators contribute to abnormal cell cycle regulation and ciliogenesis defects would lead to developing therapeutic strategies for the treatment of a wide variety of diseases, such as cancers, polycystic kidney disease (PKD), and other ciliopathy-associated disorders.
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Affiliation(s)
- Linda Xiaoyan Li
- Department of Internal Medicine, Mayo Clinic, Rochester, MN 55905, USA;
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
| | - Xiaogang Li
- Department of Internal Medicine, Mayo Clinic, Rochester, MN 55905, USA;
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Correspondence: ; Tel.: +1-507-266-0110
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5
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Massah S, Foo J, Li N, Truong S, Nouri M, Xie L, Prins GS, Buttyan R. Gli activation by the estrogen receptor in breast cancer cells: Regulation of cancer cell growth by Gli3. Mol Cell Endocrinol 2021; 522:111136. [PMID: 33347954 DOI: 10.1016/j.mce.2020.111136] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 12/11/2020] [Accepted: 12/14/2020] [Indexed: 12/24/2022]
Abstract
BACKGROUND Gli is an oncogenic transcription factor family thought to be involved in breast cancer (BrCa) cell growth. Gli activity is regulated by a post-translational proteolytic process that is suppressed by Hedgehog signaling. In prostate cancer cells, however, Gli activation is mediated by an interaction of active androgen receptor proteins with Gli3 that stabilizes Gli3 in its un-proteolyzed form. Here we show that the estrogen receptor (ER), ERα, also binds Gli3 and activates Gli in BrCa cells. Moreover, we show that ER + BrCa cells are dependent on Gli3 for cancer cell growth. METHODS Transfection with Gli-luciferase reporter was used to report Gli activity in 293FT or BrCa cells (MCF7, T47D, MDA-MB-453) with or without steroid ligands. Co-immunoprecipitation and proximity ligation were used to show association of Gli3 with ERα. Gli3 stability was determined by western blots of BrCa cell extracts. ERα knockdown or destabilization (by fulvestrant) was used to assess how loss of ERα affects estradiol-induced Gli reporter activity, formation of intranuclear ERα-Gli3 complexes and Gli3 stability. Expression of Gli1 and/or other endogenous Gli-target genes in BrCa cells were measured by qPCR in the presence or absence of estradiol. Gli3 knockdown was assessed for effects on BrCa cell growth using the Cyquant assay. RESULTS ERα co-transfection increased Gli reporter activity in 293FT cells that was further increased by estradiol. Gli3 co-precipitated in ERα immunoprecipitates. Acute (2 h) estradiol increased Gli reporter activity and the formation of intranuclear ERα-Gli3 complexes in ER + BrCa cells but more chronic estradiol (48 h) reduced ERα-Gli complexes commensurate with reduced ERα levels. Gli3 stability and endogenous activity was only increased by more chronic estradiol treatment. Fulvestrant or ERα knockdown suppressed E2-induction of Gli activity, intranuclear ERα-Gli3 complexes and stabilization of Gli3. Gli3 knockdown significantly reduced the growth of BrCa cells. CONCLUSIONS ERα interacts with Gli3 in BrCa cells and estradiol treatment leads to Gli3 stabilization and increased expression of Gli-target genes. Furthermore, we found tthat Gli3 is necessary for BrCa cell growth. These results support the idea that the ERα-Gli interaction and Gli3 may be novel targets for effective control of BrCa growth.
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Affiliation(s)
- Shabnam Massah
- The Vancouver Prostate Centre, Canada; The Department of Urologic Sciences, University of British Columbia, Canada
| | - Jane Foo
- The Vancouver Prostate Centre, Canada; Interdisciplinary Oncology, University of British Columbia, Canada
| | - Na Li
- The Vancouver Prostate Centre, Canada
| | | | | | - Lishi Xie
- The Department of Urology, University of Illinois at Chicago, Canada
| | - Gail S Prins
- The Department of Urology, University of Illinois at Chicago, Canada
| | - Ralph Buttyan
- The Vancouver Prostate Centre, Canada; The Department of Urologic Sciences, University of British Columbia, Canada.
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6
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Cameron MC, Lee E, Hibler BP, Barker CA, Mori S, Cordova M, Nehal KS, Rossi AM. Basal cell carcinoma: Epidemiology; pathophysiology; clinical and histological subtypes; and disease associations. J Am Acad Dermatol 2019; 80:303-317. [PMID: 29782900 DOI: 10.1016/j.jaad.2018.03.060] [Citation(s) in RCA: 237] [Impact Index Per Article: 47.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 03/19/2018] [Accepted: 03/21/2018] [Indexed: 12/17/2022]
Abstract
As the most common human cancer worldwide and continuing to increase in incidence, basal cell carcinoma is associated with significant morbidity and cost. Continued advances in research have refined both our insight and approach to this seemingly ubiquitous disease. This 2-part continuing medical education article will provide a comprehensive and contemporary review of basal cell carcinoma. The first article in this series describes our current understanding of this disease regarding epidemiology, cost, clinical and histopathologic presentations, carcinogenesis, natural history, and disease associations.
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Affiliation(s)
- Michael C Cameron
- Dermatology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Erica Lee
- Dermatology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Brian P Hibler
- Dermatology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Christopher A Barker
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Shoko Mori
- Dermatology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Miguel Cordova
- Dermatology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Kishwer S Nehal
- Dermatology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Anthony M Rossi
- Dermatology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York.
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7
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Downregulation of the Sonic Hedgehog/Gli pathway transcriptional target Neogenin-1 is associated with basal cell carcinoma aggressiveness. Oncotarget 2017; 8:84006-84018. [PMID: 29137400 PMCID: PMC5663572 DOI: 10.18632/oncotarget.21061] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 09/03/2017] [Indexed: 12/24/2022] Open
Abstract
Basal Cell Carcinoma (BCC) is one of the most diagnosed cancers worldwide. It develops due to an unrestrained Sonic Hedgehog (SHH) signaling activity in basal cells of the skin. Certain subtypes of BCC are more aggressive than others, although the molecular basis of this phenomenon remains unknown. We have previously reported that Neogenin-1 (NEO1) is a downstream target gene of the SHH/GLI pathway in neural tissue. Given that SHH participates in epidermal homeostasis, here we analyzed the epidermal expression of NEO1 in order to identify whether it plays a role in adult epidermis or BCC. We describe the mRNA and protein expression profile of NEO1 and its ligands (Netrin-1 and RGMA) in human and mouse control epidermis and in a broad range of human BCCs. We identify in human BCC a significant positive correlation in the levels of NEO1 receptor, NTN-1 and RGMA ligands with respect to GLI1, the main target gene of the canonical SHH pathway. Moreover, we show via cyclopamine inhibition of the SHH/GLI pathway of ex vivo cultures that NEO1 likely functions as a downstream target of SHH/GLI signaling in the skin. We also show how Neo1 expression decreases throughout BCC progression in the K14-Cre:Ptch1lox/lox mouse model and that aggressive subtypes of human BCC exhibit lower levels of NEO1 than non-aggressive BCC samples. Taken together, these data suggest that NEO1 is a SHH/GLI target in epidermis. We propose that NEO1 may be important in tumor onset and is then down-regulated in advanced BCC or aggressive subtypes.
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8
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Phua SC, Chiba S, Suzuki M, Su E, Roberson EC, Pusapati GV, Schurmans S, Setou M, Rohatgi R, Reiter JF, Ikegami K, Inoue T. Dynamic Remodeling of Membrane Composition Drives Cell Cycle through Primary Cilia Excision. Cell 2017; 168:264-279.e15. [PMID: 28086093 DOI: 10.1016/j.cell.2016.12.032] [Citation(s) in RCA: 224] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 10/27/2016] [Accepted: 12/21/2016] [Indexed: 12/16/2022]
Abstract
The life cycle of a primary cilium begins in quiescence and ends prior to mitosis. In quiescent cells, the primary cilium insulates itself from contiguous dynamic membrane processes on the cell surface to function as a stable signaling apparatus. Here, we demonstrate that basal restriction of ciliary structure dynamics is established by the cilia-enriched phosphoinositide 5-phosphatase, Inpp5e. Growth induction displaces ciliary Inpp5e and accumulates phosphatidylinositol 4,5-bisphosphate in distal cilia. This change triggers otherwise-forbidden actin polymerization in primary cilia, which excises cilia tips in a process we call cilia decapitation. While cilia disassembly is traditionally thought to occur solely through resorption, we show that an acute loss of IFT-B through cilia decapitation precedes resorption. Finally, we propose that cilia decapitation induces mitogenic signaling and constitutes a molecular link between the cilia life cycle and cell-division cycle. This newly defined ciliary mechanism may find significance in cell proliferation control during normal development and cancer.
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Affiliation(s)
- Siew Cheng Phua
- Department of Cell Biology and Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Shuhei Chiba
- Laboratory of Biological Science, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
| | - Masako Suzuki
- Advanced Research Facilities and Services, Preeminent Medical Photonics Education and Research Center, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan
| | - Emily Su
- Department of Cell Biology and Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Elle C Roberson
- Department of Biochemistry and Biophysics and Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Ganesh V Pusapati
- Departments of Medicine and Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | | | - Mitsutoshi Setou
- Department of Cellular and Molecular Anatomy and International Mass Imaging Center, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan
| | - Rajat Rohatgi
- Departments of Medicine and Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jeremy F Reiter
- Department of Biochemistry and Biophysics and Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Koji Ikegami
- Department of Cellular and Molecular Anatomy and International Mass Imaging Center, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan.
| | - Takanari Inoue
- Department of Cell Biology and Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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9
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Ermilov AN, Kumari A, Li L, Joiner AM, Grachtchouk MA, Allen BL, Dlugosz AA, Mistretta CM. Maintenance of Taste Organs Is Strictly Dependent on Epithelial Hedgehog/GLI Signaling. PLoS Genet 2016; 12:e1006442. [PMID: 27893742 PMCID: PMC5125561 DOI: 10.1371/journal.pgen.1006442] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 10/21/2016] [Indexed: 12/12/2022] Open
Abstract
For homeostasis, lingual taste papilla organs require regulation of epithelial cell survival and renewal, with sustained innervation and stromal interactions. To investigate a role for Hedgehog/GLI signaling in adult taste organs we used a panel of conditional mouse models to manipulate GLI activity within epithelial cells of the fungiform and circumvallate papillae. Hedgehog signaling suppression rapidly led to taste bud loss, papilla disruption, and decreased proliferation in domains of papilla epithelium that contribute to taste cells. Hedgehog responding cells were eliminated from the epithelium but retained in the papilla stromal core. Despite papilla disruption and loss of taste buds that are a major source of Hedgehog ligand, innervation to taste papillae was maintained, and not misdirected, even after prolonged GLI blockade. Further, vimentin-positive fibroblasts remained in the papilla core. However, retained innervation and stromal cells were not sufficient to maintain taste bud cells in the context of compromised epithelial Hedgehog signaling. Importantly taste organ disruption after GLI blockade was reversible in papillae that retained some taste bud cell remnants where reactivation of Hedgehog signaling led to regeneration of papilla epithelium and taste buds. Therefore, taste bud progenitors were either retained during epithelial GLI blockade or readily repopulated during recovery, and were poised to regenerate taste buds once Hedgehog signaling was restored, with innervation and papilla connective tissue elements in place. Our data argue that Hedgehog signaling is essential for adult tongue tissue maintenance and that taste papilla epithelial cells represent the key targets for physiologic Hedgehog-dependent regulation of taste organ homeostasis. Because disruption of GLI transcriptional activity in taste papilla epithelium is sufficient to drive taste organ loss, similar to pharmacologic Hedgehog pathway inhibition, the findings suggest that taste alterations in cancer patients using systemic Hedgehog pathway inhibitors result principally from interruption of signaling activity in taste papillae.
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Affiliation(s)
- Alexandre N Ermilov
- Department of Dermatology, Medical School, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Archana Kumari
- Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Libo Li
- Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Ariell M Joiner
- Department of Cell and Developmental Biology, Medical School, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Marina A Grachtchouk
- Department of Dermatology, Medical School, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Benjamin L Allen
- Department of Cell and Developmental Biology, Medical School, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Andrzej A Dlugosz
- Department of Dermatology, Medical School, University of Michigan, Ann Arbor, Michigan, United States of America.,Department of Cell and Developmental Biology, Medical School, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Charlotte M Mistretta
- Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, Michigan, United States of America
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10
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McInerney-Leo AM, Harris JE, Gattas M, Peach EE, Sinnott S, Dudding-Byth T, Rajagopalan S, Barnett CP, Anderson LK, Wheeler L, Brown MA, Leo PJ, Wicking C, Duncan EL. Fryns Syndrome Associated with Recessive Mutations in PIGN in two Separate Families. Hum Mutat 2016; 37:695-702. [PMID: 27038415 DOI: 10.1002/humu.22994] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 03/17/2016] [Indexed: 01/08/2023]
Abstract
Fryns syndrome is an autosomal recessive condition characterized by congenital diaphragmatic hernia (CDH), dysmorphic facial features, distal digital hypoplasia, and other associated malformations, and is the most common syndromic form of CDH. No gene has been associated with this condition. Whole-exome sequence data from two siblings and three unrelated individuals with Fryns syndrome were filtered for rare, good quality, coding mutations fitting a recessive inheritance model. Compound heterozygous mutations in PIGN were identified in the siblings, with appropriate parental segregation: a novel STOP mutation (c.1966C>T: p.Glu656X) and a rare (minor allele frequency <0.001) donor splice site mutation (c.1674+1G>C) causing skipping of exon 18 and utilization of a cryptic acceptor site in exon 19. A further novel homozygous STOP mutation in PIGN (c.694A>T: p.Lys232X) was detected in one unrelated case. All three variants affected highly conserved bases. The two remaining cases were negative for PIGN mutations. Mutations in PIGN have been reported in cases with multiple congenital anomalies, including one case with syndromic CDH. Fryns syndrome can be caused by recessive mutations in PIGN. Whether PIGN affects other syndromic and non-syndromic forms of CDH warrants investigation.
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Affiliation(s)
- Aideen M McInerney-Leo
- The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, QLD, Australia.,Queensland University of Technology (QUT), Institute of Health and Biomedical Innovation (IHBI), Brisbane, QLD, Australia
| | - Jessica E Harris
- The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, QLD, Australia.,Queensland University of Technology (QUT), Institute of Health and Biomedical Innovation (IHBI), Brisbane, QLD, Australia
| | - Michael Gattas
- Brisbane Genetics, Wesley Medical Centre, Auchenflower, QLD, Australia
| | - Elizabeth E Peach
- Specialized Obstetric and Gynaecological Imaging, South Bank, QLD, Australia
| | - Stephen Sinnott
- Specialized Obstetric and Gynaecological Imaging, South Bank, QLD, Australia
| | - Tracy Dudding-Byth
- Hunter Genetics, NSW Genetics of Learning Disability (GOLD) Service and GrowUpWell Priority Research Centre, The University of Newcastle, NSW, Australia
| | - Sulekha Rajagopalan
- Department of Clinical Genetics, Liverpool Hospital, Liverpool BC, NSW, Australia
| | - Christopher P Barnett
- Paediatric and Reproductive Genetics Unit, Women's and Children's Hospital/SA Pathology, North Adelaide, South Australia.,School of Medicine, University of Adelaide, North Adelaide, SA, Australia
| | - Lisa K Anderson
- Queensland University of Technology (QUT), Institute of Health and Biomedical Innovation (IHBI), Brisbane, QLD, Australia
| | - Lawrie Wheeler
- The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, QLD, Australia.,Queensland University of Technology (QUT), Institute of Health and Biomedical Innovation (IHBI), Brisbane, QLD, Australia
| | - Matthew A Brown
- Queensland University of Technology (QUT), Institute of Health and Biomedical Innovation (IHBI), Brisbane, QLD, Australia
| | - Paul J Leo
- The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, QLD, Australia.,Queensland University of Technology (QUT), Institute of Health and Biomedical Innovation (IHBI), Brisbane, QLD, Australia
| | - Carol Wicking
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, Australia
| | - Emma L Duncan
- The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, QLD, Australia.,Queensland University of Technology (QUT), Institute of Health and Biomedical Innovation (IHBI), Brisbane, QLD, Australia.,School of Medicine, Faculty of Medicine and Biomedical Sciences, University of Queensland, Australia.,Department of Endocrinology, James Mayne Building, Royal Brisbane and Women's Hospital, Butterfield Street, Herston, QLD, Australia
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11
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Petrovic I, Milivojevic M, Popovic J, Schwirtlich M, Rankovic B, Stevanovic M. SOX18 Is a Novel Target Gene of Hedgehog Signaling in Cervical Carcinoma Cell Lines. PLoS One 2015; 10:e0143591. [PMID: 26588701 PMCID: PMC4654472 DOI: 10.1371/journal.pone.0143591] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 11/06/2015] [Indexed: 02/08/2023] Open
Abstract
Although there is much evidence showing functional relationship between Hedgehog pathway, in particular Sonic hedgehog, and SOX transcription factors during embryonic development, scarce data are available regarding their crosstalk in cancer cells. SOX18 protein plays an important role in promoting tumor angiogenesis and therefore emerged as a promising potential target in antiangiogenic tumor therapy. Recently it became evident that expression of SOX18 gene in tumors is not restricted to endothelium of accompanying blood and lymphatic vessels, but in tumor cells as well.In this paper we have identified human SOX18 gene as a novel target gene of Hedgehog signaling in cervical carcinoma cell lines. We have presented data showing that expression of SOX18 gene is regulated by GLI1 and GLI2 transcription factors, final effectors of Hedgehog signaling, and that modulation of Hedgehog signaling activity in considerably influence SOX18 expression. We consider important that Hedgehog pathway inhibitors reduced SOX18 expression, thus showing, for the first time, possibility for manipulationwith SOX18 gene expression. In addition, we analyzed the role of SOX18 in malignant potential of cervical carcinoma cell line, and showed that its overexpression has no influence on cells proliferation and viability, but substantially promotes migration and invasion of cells in vitro. Pro-migratory effect of SOX18 suggests its role in promoting malignant spreading, possibly in response to Hedgehog activation.
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Affiliation(s)
- Isidora Petrovic
- Laboratory for Human Molecular Genetics, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, P.O.BOX 23, 11000 Belgrade, Serbia
- * E-mail:
| | - Milena Milivojevic
- Laboratory for Human Molecular Genetics, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, P.O.BOX 23, 11000 Belgrade, Serbia
| | - Jelena Popovic
- Laboratory for Human Molecular Genetics, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, P.O.BOX 23, 11000 Belgrade, Serbia
| | - Marija Schwirtlich
- Laboratory for Human Molecular Genetics, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, P.O.BOX 23, 11000 Belgrade, Serbia
| | - Branislava Rankovic
- Laboratory for Human Molecular Genetics, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, P.O.BOX 23, 11000 Belgrade, Serbia
| | - Milena Stevanovic
- Laboratory for Human Molecular Genetics, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, P.O.BOX 23, 11000 Belgrade, Serbia
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12
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Activation of Sonic hedgehog signaling in neural progenitor cells promotes glioma development in the zebrafish optic pathway. Oncogenesis 2014; 3:e96. [PMID: 24686726 PMCID: PMC4038393 DOI: 10.1038/oncsis.2014.10] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 02/11/2014] [Accepted: 02/27/2014] [Indexed: 12/17/2022] Open
Abstract
Dysregulation of Sonic hedgehog (Shh) signaling has been implicated in glioma pathogenesis. Yet, the role of this pathway in gliomagenesis remains controversial because of the lack of relevant animal models. Using the cytokeratin 5 promoter, we ectopically expressed a constitutively active zebrafish Smoothened (Smoa1) in neural progenitor cells and analyzed tumorigenic capacity of activated Shh signaling in both transient and stable transgenic fish. Transient transgenic fish overexpressing Smoa1 developed retinal and brain tumors, suggesting smoa1 is oncogenic in the zebrafish central nervous system (CNS). We further established stable transgenic lines that simultaneously developed optic pathway glioma (OPG) and various retinal tumors. In one of these lines, up to 80% of F1 and F2 fish developed tumors within 1 year of age. Microarray analysis of tumor samples showed upregulated expression of genes involved in the cell cycle, cancer signaling and Shh downstream targets ptc1, gli1 and gli2a. Tumors also exhibited specific gene signatures characteristic of radial glia and progenitor cells as transcriptions of radial glia genes cyp19a1b, s100β, blbp, gfap and the stem/progenitor genes nestin and sox2 were significantly upregulated. Overexpression of GFAP, S100β, BLBP and Sox2 was confirmed by immunofluorescence. We also detected overexpression of Mdm2 throughout the optic pathway in fish with OPG, therefore implicating the Mdm2–Tp53 pathway in glioma pathogenesis. In conclusion, we demonstrate that activated Shh signaling initiates tumorigenesis in the zebrafish CNS and provide the first OPG model not associated with neurofibromatosis 1.
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13
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Gli1 inhibition suppressed cell growth and cell cycle progression and induced apoptosis as well as autophagy depending on ERK1/2 activity in human chondrosarcoma cells. Cell Death Dis 2014; 5:e979. [PMID: 24384722 PMCID: PMC4040663 DOI: 10.1038/cddis.2013.497] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 10/24/2013] [Accepted: 11/08/2013] [Indexed: 01/03/2023]
Abstract
The transcription factor glioma-associated oncogene 1 (Gli1) has been recognized as a very important nuclear executor at the distal end of the Hedgehog (Hh) signal pathway, which has crucial roles in regulating many developmental processes, such as pattern formation, differentiation, proliferation, and apoptosis. Overexpression of patched 1 protein and Gli1 or constitutively active Indian Hedgehog (IHh)-parathyroid hormone-related protein signal pathway may lead to musculoskeletal tumorigenesis. However, for chondrosarcoma few studies have paid close attention to the IHh-Gli1 signal transduction cascade and more work needs to be carried out to fully elucidate Gli1 protein functions. Here we show that the IHh signal pathway was activated in chondrosarcoma, and knocking down the expression of Gli1 attenuated the disturbed IHh signal pathway, which not only suppressed cell proliferation and promoted G2/M cell cycle arrest but also enhanced cell apoptosis by downregulating Bcl-2 and Bcl-xl expression. Furthermore, Gli1 downregulation, not cyclopamine, induced autophagy by regulating mTOR phosphorylation, and inhibition of autophagy prevented Gli1 small interfering RNA-mediated cell death. We also demonstrated that extracellular signal-regulated kinase 1/2 activity may mediate these antiproliferative events induced by Gli1 inhibition. These results indicate that Gli1 inhibition could ultimately provide a promising new approach for chondrosarcoma treatment.
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Abstract
Cancer, one of the leading causes of death worldwide is estimated to increase to approximately 13.1 million by 2030. This has amplified the research in oncology towards the exploration of novel targets. Recently there has been lots of interest regarding the hedgehog (Hh) pathway, which plays a significant role in the development of organs and tissues during embryonic and postnatal periods. In a normal person, the Hh signaling pathway is under inhibition and gets activated upon the binding of Hh ligand to a transmembrane receptor called Patched (PTCH1) thus allowing the transmembrane protein, smoothened (SMO) to transfer signals through various proteins. One of the newer drugs namely vismodegib involves the inhibition of Hh pathway and has shown promising results in the treatment of advanced basal-cell carcinoma as well as medulloblastoma. It has been granted approval by US Food and Drug Administration's (US FDA) priority review program on January 30, 2012 for the treatment of advanced basal-cell carcinoma. The drug is also being evaluated in malignancies like medulloblastoma, pancreatic cancer, multiple myeloma, chondrosarcoma and prostate cancer. Moreover various Hh inhibitors namely LDE 225, saridegib, BMS 833923, LEQ 506, PF- 04449913 and TAK-441 are also undergoing phase I and II trials for different neoplasms. Hence this review will describe briefly the Hh pathway and the novel drug vismodegib.
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Affiliation(s)
- Selvarajan Sandhiya
- Division of Clinical Pharmacology, Jawaharlal Institute of Postgradute Medical Education and Research, Puducherry, India
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15
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Hedgehog signaling acts with the temporal cascade to promote neuroblast cell cycle exit. PLoS Biol 2013; 11:e1001494. [PMID: 23468593 PMCID: PMC3582610 DOI: 10.1371/journal.pbio.1001494] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Accepted: 01/14/2013] [Indexed: 11/19/2022] Open
Abstract
During the development of the Drosophila nervous system, the developmentally regulated Hedgehog pathway, together with a series of temporal transcription factors, schedules the end of neurogenesis. In Drosophila postembryonic neuroblasts, transition in gene expression programs of a cascade of transcription factors (also known as the temporal series) acts together with the asymmetric division machinery to generate diverse neurons with distinct identities and regulate the end of neuroblast proliferation. However, the underlying mechanism of how this “temporal series” acts during development remains unclear. Here, we show that Hh signaling in the postembryonic brain is temporally regulated; excess (earlier onset of) Hh signaling causes premature neuroblast cell cycle exit and under-proliferation, whereas loss of Hh signaling causes delayed cell cycle exit and excess proliferation. Moreover, the Hh pathway functions downstream of Castor but upstream of Grainyhead, two components of the temporal series, to schedule neuroblast cell cycle exit. Interestingly, hh is likely a target of Castor. Hence, Hh signaling provides a link between the temporal series and the asymmetric division machinery in scheduling the end of neurogenesis. In almost all metazoans, neurons are produced by a group of neural stem cells/progenitors in a precise temporal manner, which is important for generating a functional nervous system. In Drosophila, this “timing” mechanism is mainly governed by the sequential switching of transcription factors in neural stem cells called neuroblasts, such that neuronal fate is associated with its birth order. These temporal factors also coordinate the termination of neuroblast division towards the end of neurogenesis. In this study, we show that Hedgehog (Hh) signaling also regulates the division rate of neuroblasts during their proliferative phase at larval stage, as well as the cessation of proliferation at early pupal stage. Excessive Hh signaling causes premature neuroblast cell cycle exit and early termination of neurogenesis, while loss of Hh signaling results in prolonged proliferation of neuroblasts beyond its physiological window. We also find that Hh signaling acts in concert with the temporal transcription factors, and is itself regulated by these factors. We hypothesize that this mode of interaction (temporal transcription factors with developmentally regulated signals like Hh) during neurogenesis could be widely conserved in other organisms.
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16
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Itou J, Kawakami H, Quach T, Osterwalder M, Evans SM, Zeller R, Kawakami Y. Islet1 regulates establishment of the posterior hindlimb field upstream of the Hand2-Shh morphoregulatory gene network in mouse embryos. Development 2012; 139:1620-9. [PMID: 22438573 DOI: 10.1242/dev.073056] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
How divergent genetic systems regulate a common pathway during the development of two serial structures, forelimbs and hindlimbs, is not well understood. Specifically, HAND2 has been shown to regulate Shh directly to initiate its expression in the posterior margin of the limb mesenchyme. Although the Hand2-Shh morphoregulatory system operates in both the forelimb and hindlimb bud, a recent analysis suggested that its upstream regulation is different in the forelimb and hindlimb bud. A combination of all four Hox9 genes is required for Hand2 expression in the forelimb-forming region; however, it remains elusive what genetic system regulates the Hand2-Shh pathway in the hindlimb-forming region. By conditional inactivation of Islet1 in the hindlimb-forming region using the Hoxb6Cre transgene, we show that Islet1 is required for establishing the posterior hindlimb field, but not the forelimb field, upstream of the Hand2-Shh pathway. Inactivation of Islet1 caused the loss of posterior structures in the distal and proximal regions, specifically in the hindlimb. We found that Hand2 expression was downregulated in the hindlimb field and that Shh expression was severely impaired in the hindlimb bud. In the Hoxb6Cre; Islet1 mutant pelvis, the proximal element that is formed in a Shh-independent manner, displayed complementary defects in comparison with Pitx1(-/-) hindlimbs. This suggests that Islet1 and Pitx1 function in parallel during girdle development in hindlimbs, which is in contrast with the known requirement for Tbx5 in girdle development in forelimbs. Our studies have identified a role for Islet1 in hindlimb-specific development and have revealed Islet1 functions in two distinct processes: regulation upstream of the Hand2-Shh pathway and contributions to girdle development.
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Affiliation(s)
- Junji Itou
- Department of Genetics, Cell Biology and Development, University of Minnesota, 321 Church St. SE. Minneapolis, MN 55455, USA
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17
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Huang HY, Liu JT, Yan HY, Tsai HJ. Arl6ip1 Plays a Role in Proliferation during Zebrafish Retinogenesis. Cells Tissues Organs 2012; 196:161-74. [DOI: 10.1159/000331589] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/03/2011] [Indexed: 11/19/2022] Open
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18
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Steg A, Amm HM, Novak Z, Frost AR, Johnson MR. Gli3 mediates cell survival and sensitivity to cyclopamine in pancreatic cancer. Cancer Biol Ther 2010; 10:893-902. [PMID: 20814245 DOI: 10.4161/cbt.10.9.13252] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Activation of the hedgehog (HH) pathway plays a critical role in the development and continued growth of pancreatic adenocarcinoma (PAC). Cyclopamine, a HH pathway inhibitor, has been shown to suppress PAC cell proliferation in vitro and in vivo. However, the molecular basis of response to cyclopamine has not been fully elucidated nor have genes that predict sensitivity to this compound been identified. To better understand these features of HH pathway inhibition, we evaluated the biological and molecular effects of cyclopamine in vitro. The viability of 9 human PAC cell lines following cyclopamine exposure was determined using MTS assay. Proliferation and induction of apoptosis in treated cells were examined by bromo-deoxyuridine incorporation, caspase activation, and mitochondrial membrane potential. Gene expression before and after cyclopamine treatment was determined using Taqman real-time quantitative polymerase chain reaction (RTQ-PCR) and Taqman low-density array (TLDA). Among the cell lines examined, cyclopamine IC50 values ranged from 8.79 to >30 µM. Response to cyclopamine included reduced cell proliferation and induction of apoptosis with and without mitochondrial membrane depolarization. Regression analysis revealed that GLI3 expression significantly correlated with cyclopamine resistance (r = 0.80; p = 0.0102). Knockdown of GLI3 using siRNAs increased sensitivity to cyclopamine. In addition, GLI3 siRNAs decreased PAC cell viability and reduced expression of genes involved in HH signaling (Patched 1 and GLI1) and cell proliferation, similar to cyclopamine. These effects were not observed in PAC cells with undetectable GLI3 expression. These data suggest that Gli3 mediates cell survival and sensitivity to cyclopamine in pancreatic cancer.
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Affiliation(s)
- Adam Steg
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, Alabama, USA
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19
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The molecular genetics underlying basal cell carcinoma pathogenesis and links to targeted therapeutics. J Am Acad Dermatol 2010; 66:e167-78. [PMID: 20800318 DOI: 10.1016/j.jaad.2010.06.054] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 06/20/2010] [Accepted: 06/25/2010] [Indexed: 01/19/2023]
Abstract
Mutations in the sonic hedgehog signaling pathway play a key role in the development of basal cell carcinomas. Specifically, mutations in the PTCH1 (also known as PTCH or PTC1) and SMO genes cause tumor formation through constitutive activation of the pathway. Misregulation of the pathway has also been implicated in the nevoid basal cell carcinoma syndrome and other tumors. Understanding the function of the sonic hedgehog pathway has led to novel strategies for treatment. In this review we highlight the role of the pathway in the pathogenesis of basal cell carcinoma and review potential targeted therapies.
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20
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Seifert AW, Zheng Z, Ormerod BK, Cohn MJ. Sonic hedgehog controls growth of external genitalia by regulating cell cycle kinetics. Nat Commun 2010; 1:23. [PMID: 20975695 PMCID: PMC2964453 DOI: 10.1038/ncomms1020] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Accepted: 04/28/2010] [Indexed: 02/07/2023] Open
Abstract
The faithful positioning and growth of cells during
embryonic development is essential. In this study Seifert et al. demonstrate that
inactivation of Sonic Hedgehog during development of the genital tubercle results in a
prolonged G1 phase and a slower rate of growth. During embryonic development, cells are instructed which position to occupy, they interpret
these cues as differentiation programmes, and expand these patterns by growth. Sonic
hedgehog (Shh) specifies positional identity in many organs; however, its role in growth is
not well understood. In this study, we show that inactivation of Shh in external
genitalia extends the cell cycle from 8.5 to 14.4 h, and genital growth is reduced by ∼75%.
Transient Shh signalling establishes pattern in the genital tubercle; however,
transcriptional levels of G1 cell cycle regulators are reduced. Consequently, G1 length is
extended, leading to fewer progenitor cells entering S-phase. Cell cycle genes responded
similarly to Shh inactivation in genitalia and limbs, suggesting that Shh may regulate
growth by similar mechanisms in different organ systems. The finding that Shh regulates cell
number by controlling the length of specific cell cycle phases identifies a novel mechanism
by which Shh elaborates pattern during appendage development.
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Affiliation(s)
- Ashley W Seifert
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
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21
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Effect of betulinic acid on the regulation of Hiwi and cyclin B1 in human gastric adenocarcinoma AGS cells. Acta Pharmacol Sin 2010; 31:66-72. [PMID: 20037601 DOI: 10.1038/aps.2009.177] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
AIM To investigate the effect of betulinic acid (BA) on the proliferation, apoptosis and cell cycle of gastric adenocarcinoma cell AGS in vitro and the underlying mechanism. METHODS The effect of BA on the proliferation of AGS cells was measured by using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium (MTT) assay. Apoptosis was analyzed by using Annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) double-labeled flow cytometry (FCM) and Hoechst 33258 staining. The influence of BA on cell cycle of AGS cells was tested by PI staining. Both FCM and reverse transcription-PCR (RT-PCR) technologies were applied to detect the expression of Hiwi and Cyclin B1. RESULTS BA exhibited significant cell proliferation inhibition, as well as its potency of inducing apoptosis in AGS cells in vitro in a time- and dose-dependent manner. The IC(50) value for 24 h was 18.25 microg/mL (95% confidence interval: 15.16 to 27.31 microg/mL). Cells treated with BA showed increased cell population in G(2)/M phase, with decreased S phase population. The expression of Hiwi and Cyclin B1 was down-regulated in BA-treated AGS cells in a dose-dependent manner. CONCLUSION BA exerted potent effect on growth inhibition, G(2)/M cell cycle arrest and induction of apoptosis in AGS cells in vitro, possibly associated with the down-regulation of Hiwi and its downstream target Cyclin B1 expression. The potent antitumor capacity of BA suggested that it could be a promising new experimental anticancer agent in human gastric adenocarcinoma treatment.
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22
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Yakushiji N, Suzuki M, Satoh A, Ide H, Tamura K. Effects of activation of hedgehog signaling on patterning, growth, and differentiation in Xenopus froglet limb regeneration. Dev Dyn 2009; 238:1887-96. [PMID: 19544583 DOI: 10.1002/dvdy.22011] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Regenerating limbs of urodele amphibians and Xenopus tadpole are reconstructed along proximal-distal, anterior-posterior (AP), and dorsal-ventral axes. In contrast, a regenerated limb of the Xenopus froglet does not have digits, and only a simple cartilaginous structure referred to as a "spike" is formed. This suggests that repatterning along the AP axis is absent in the froglet blastema. Previous studies have shown that Shh and its target genes are not expressed in the froglet blastema. In this study, we activated Hedgehog signaling in the froglet blastema and found that target genes of Shh were inducible in the mesenchyme of limb blastema. Furthermore, we found that activation of the signaling had effects on blastema cell proliferation and chondrogenesis and resulted in the formation of multiple cartilaginous structures. These findings indicate that activation of signaling that is absent in the froglet blastema is effective for improvement of limb regeneration ability in the Xenopus froglet.
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Affiliation(s)
- Nayuta Yakushiji
- Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama Aoba-ku, Sendai, Japan
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23
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Wu SM, Choo ABH, Yap MGS, Chan KKK. Role of Sonic hedgehog signaling and the expression of its components in human embryonic stem cells. Stem Cell Res 2009; 4:38-49. [PMID: 19836325 DOI: 10.1016/j.scr.2009.09.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Revised: 09/07/2009] [Accepted: 09/08/2009] [Indexed: 02/08/2023] Open
Abstract
Human embryonic stem cells (hESC) are characterized by their ability to self-renew and differentiate into all cell types of the body, making them a valuable resource for regenerative medicine. Yet, the molecular mechanisms by which hESC retain their capacity for self-renewal and differentiation remain unclear. The Hedgehog signaling pathway plays a pivotal role in organogenesis and differentiation during development, and is also involved in the proliferation and cell-fate specification of neural stem cells and neural crest stem cells. As there has been no detailed study of the Sonic hedgehog (SHH) signaling pathway in hESC, this study examines the expression and functional role of SHH during hESC self-renewal and differentiation. Here, we show the gene and protein expression of key components of the SHH signaling pathway in hESC and differentiated embryoid bodies. Despite the presence of functioning pathway components, SHH plays a minimal role in maintaining pluripotency and regulating proliferation of undifferentiated hESC. However, during differentiation with retinoic acid, a GLI-responsive luciferase assay and target genes PTCH1 and GLI1 expression reveal that the SHH signaling pathway is highly activated. Besides, addition of exogenous SHH to hESC differentiated as embryoid bodies increases the expression of neuroectodermal markers Nestin, SOX1, MAP2, MSI1, and MSX1, suggesting that SHH signaling is important during hESC differentiation toward the neuroectodermal lineage. Our findings provide a new insight in understanding the SHH signaling in hESC and the further development of hESC differentiation for regenerative medicine.
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Affiliation(s)
- Selena Meiyun Wu
- Stem Cell Group, Bioprocessing Technology Institute, ASTAR (Agency for Science, Technology and Research), 20 Biopolis Way, No. 06-01 Centros, Singapore 138668, Singapore
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Hirose Y, Itoh T, Miyajima A. Hedgehog signal activation coordinates proliferation and differentiation of fetal liver progenitor cells. Exp Cell Res 2009; 315:2648-57. [PMID: 19559697 DOI: 10.1016/j.yexcr.2009.06.018] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Revised: 05/11/2009] [Accepted: 06/16/2009] [Indexed: 02/07/2023]
Abstract
Hedgehog (Hh) signaling plays crucial roles in development and homeostasis of various organs. In the adult liver, it regulates proliferation and/or viability of several types of cells, particularly under injured conditions, and is also implicated in stem/progenitor cell maintenance. However, the role of this signaling pathway during the normal developmental process of the liver remains elusive. Although Sonic hedgehog (Shh) is expressed in the ventral foregut endoderm from which the liver derives, the expression disappears at the onset of the liver bud formation, and its possible recurrence at the later stages has not been investigated. Here we analyzed the activation and functional relevance of Hh signaling during the mouse fetal liver development. At E11.5, Shh and an activation marker gene for Hh signaling, Gli1, were expressed in Dlk(+) hepatoblasts, the fetal liver progenitor cells, and the expression was rapidly decreased thereafter as the development proceeded. In the culture of Dlk(+) hepatoblasts isolated from the E11.5 liver, activation of Hh signaling stimulated their proliferation and this effect was cancelled by a chemical Hh signaling inhibitor, cyclopamine. In contrast, hepatocyte differentiation of Dlk(+) hepatoblasts in vitro as manifested by the marker gene expression and acquisition of ammonia clearance activity was significantly inhibited by forced activation of Hh signaling. Taken together, these results demonstrate the temporally restricted manner of Hh signal activation and its role in promoting the hepatoblast proliferation, and further suggest that the pathway needs to be shut off for the subsequent hepatic differentiation of hepatoblasts to proceed normally.
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Affiliation(s)
- Yoshikazu Hirose
- Laboratory of Cell Growth and Differentiation, Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan
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25
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Cobourne MT, Xavier GM, Depew M, Hagan L, Sealby J, Webster Z, Sharpe PT. Sonic hedgehog signalling inhibits palatogenesis and arrests tooth development in a mouse model of the nevoid basal cell carcinoma syndrome. Dev Biol 2009; 331:38-49. [PMID: 19394325 PMCID: PMC2696601 DOI: 10.1016/j.ydbio.2009.04.021] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Revised: 04/16/2009] [Accepted: 04/20/2009] [Indexed: 12/21/2022]
Abstract
Nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant or spontaneous disorder characterized by multiple cutaneous basal cell carcinomas, odontogenic keratocysts, skeletal anomalies and facial dysmorphology, including cleft lip and palate. Causative mutations for NBCCS occur in the PTCH1 gene on chromosome 9q22.3–q31, which encodes the principle receptor for the Hedgehog signalling pathway. We have investigated the molecular basis of craniofacial defects seen in NBCCS using a transgenic mouse model expressing Shh in basal epithelium under a Keratin-14 promoter. These mice have an absence of flat bones within the skull vault, hypertelorism, open-bite malocclusion, cleft palate and arrested tooth development. Significantly, increased Hedgehog signal transduction in these mice can influence cell fate within the craniofacial region. In medial edge epithelium of the palate, Shh activity prevents apoptosis and subsequent palatal shelf fusion. In contrast, high levels of Shh in odontogenic epithelium arrests tooth development at the bud stage, secondary to a lack of cell proliferation in this region. These findings illustrate the importance of appropriately regulated Hedgehog signalling during early craniofacial development and demonstrate that oro-facial clefting and hypodontia seen in NBCCS can occur as a direct consequence of increased Shh signal activity within embryonic epithelial tissues.
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Affiliation(s)
- Martyn T Cobourne
- Department of Craniofacial Development and Orthodontics, Dental Institute, King's College London, Floor 27, Guy's Hospital, London SE1 9RT, UK.
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26
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Abstract
Hematopoietic stem/progenitor cells (HSPCs) transplantation is hampered by the low number of stem cells per sample. To tackle this obstacle, several protocols for expansion of HSPCs in vitro are currently in development, such as the use of cytokine cocktails, coculture with mesenchymal stem cells as feeder cells, and cell culture in bioreactors. With the progress in the understanding of the molecular and cellular mechanisms regulating HSPCs maintenance and expansion, more recent approaches have involved transcription regulation, cell cycle regulation, telomerase regulation, and chromatin-modifying agents. The potential clinical application and safety issues relevant to the expanded HSPCs are also discussed in this review.
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Affiliation(s)
- Wu Hai-Jiang
- Department of Pathology, Hebei Medical University, Shijiazhuang, China
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Thomas NA, Koudijs M, van Eeden FJM, Joyner AL, Yelon D. Hedgehog signaling plays a cell-autonomous role in maximizing cardiac developmental potential. Development 2008; 135:3789-99. [PMID: 18842815 DOI: 10.1242/dev.024083] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Elucidation of the complete roster of signals required for myocardial specification is crucial to the future of cardiac regenerative medicine. Prior studies have implicated the Hedgehog (Hh) signaling pathway in the regulation of multiple aspects of heart development. However, our understanding of the contribution of Hh signaling to the initial specification of myocardial progenitor cells remains incomplete. Here, we show that Hh signaling promotes cardiomyocyte formation in zebrafish. Reduced Hh signaling creates a cardiomyocyte deficit, and increased Hh signaling creates a surplus. Through fate-mapping, we find that Hh signaling is required at early stages to ensure specification of the proper number of myocardial progenitors. Genetic inducible fate mapping in mouse indicates that myocardial progenitors respond directly to Hh signals, and transplantation experiments in zebrafish demonstrate that Hh signaling acts cell autonomously to promote the contribution of cells to the myocardium. Thus, Hh signaling plays an essential early role in defining the optimal number of cardiomyocytes, making it an attractive target for manipulation of multipotent progenitor cells.
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Affiliation(s)
- Natalie A Thomas
- Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA
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Prykhozhij SV, Neumann CJ. Distinct roles of Shh and Fgf signaling in regulating cell proliferation during zebrafish pectoral fin development. BMC DEVELOPMENTAL BIOLOGY 2008; 8:91. [PMID: 18811955 PMCID: PMC2562996 DOI: 10.1186/1471-213x-8-91] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2008] [Accepted: 09/23/2008] [Indexed: 11/13/2022]
Abstract
Background Cell proliferation in multicellular organisms must be coordinated with pattern formation. The major signaling pathways directing pattern formation in the vertebrate limb are well characterized, and we have therefore chosen this organ to examine the interaction between proliferation and patterning. Two important signals for limb development are members of the Hedgehog (Hh) and Fibroblast Growth Factor (Fgf) families of secreted signaling proteins. Sonic hedgehog (Shh) directs pattern formation along the anterior/posterior axis of the limb, whereas several Fgfs in combination direct pattern formation along the proximal/distal axis of the limb. Results We used the genetic and pharmacological amenability of the zebrafish model system to dissect the relative importance of Shh and Fgf signaling in regulating proliferation during development of the pectoral fin buds. In zebrafish mutants disrupting the shh gene, proliferation in the pectoral fin buds is initially normal, but later is strongly reduced. Correlating with this reduction, Fgf signaling is normal at early stages, but is later lost in shh mutants. Furthermore, pharmacological inhibition of Hh signaling for short periods has little effect on either Fgf signaling, or on expression of G1- and S-phase cell-cycle genes, whereas long periods of inhibition lead to the downregulation of both. In contrast, even short periods of pharmacological inhibition of Fgf signaling lead to strong disruption of proliferation in the fin buds, without affecting Shh signaling. To directly test the ability of Fgf signaling to regulate proliferation in the absence of Shh signaling, we implanted beads soaked with Fgf protein into shh mutant fin buds. We find that Fgf-soaked beads rescue proliferation in the pectoral find buds of shh mutants, indicating that Fgf signaling is sufficient to direct proliferation in zebrafish fin buds in the absence of Shh. Conclusion Previous studies have shown that both Shh and Fgf signaling are crucial for outgrowth of the vertebrate limb. The results presented here show that the role of Shh in this process is indirect, and is mediated by its effect on Fgf signaling. By contrast, the activity of the Fgf pathway affects proliferation directly and independently of its effect on Shh. These results show that Fgf signaling is of primary importance in directing outgrowth of the limb bud, and clarify the role of the Shh-Fgf feedback loop in regulating proliferation.
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Affiliation(s)
- Sergey V Prykhozhij
- Developmental Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, Heidelberg, Germany.
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29
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Bastida MF, Ros MA. How do we get a perfect complement of digits? Curr Opin Genet Dev 2008; 18:374-80. [PMID: 18672062 DOI: 10.1016/j.gde.2008.06.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2008] [Revised: 06/13/2008] [Accepted: 06/17/2008] [Indexed: 12/26/2022]
Abstract
A crucial issue in limb development is how a correct set of precisely shaped digits forms in the digital plate. This process relies on patterning across the anterior-posterior axis of the limb bud, which is under the control of Sonic hedgehog emanating from the zone of polarizing activity. Recently, Sonic hedgehog function in the limb bud has been shown to have a dual character controlling both growth and patterning of the digital field. This finding has prompted the proposal of new models of how these two functions are achieved, and this will be discussed in this review.
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Affiliation(s)
- Ma Félix Bastida
- Departamento de Anatomía y Biología Celular, Universidad de Cantabria, C/ Herrera Oria s/n, E-39011 Santander, Spain
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30
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Affiliation(s)
- Clifford J Tabin
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.
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31
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Francis-West P, Hill R. Uncoupling the Role of Sonic Hedgehog in Limb Development: Growth and Specification. Sci Signal 2008; 1:pe34. [DOI: 10.1126/scisignal.126pe34] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Philippa Francis-West
- Department of Craniofacial Development, King’s College London, Guy’s Tower, Floor 27, London Bridge, London SE1 9RT, UK
| | - Robert Hill
- Medical Research Council Human Genetics Unit, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
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Towers M, Mahood R, Yin Y, Tickle C. Integration of growth and specification in chick wing digit-patterning. Nature 2008; 452:882-6. [PMID: 18354396 DOI: 10.1038/nature06718] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Accepted: 01/15/2008] [Indexed: 11/09/2022]
Abstract
In the classical model of chick wing digit-patterning, the polarizing region--a group of cells at the posterior margin of the early bud--produces a morphogen gradient, now known to be based on Sonic hedgehog (Shh), that progressively specifies anteroposterior positional identities in the posterior digit-forming region. Here we add an integral growth component to this model by showing that Shh-dependent proliferation of prospective digit progenitor cells is essential for specifying the complete pattern of digits across the anteroposterior axis. Inhibiting Shh signalling in early wing buds reduced anteroposterior expansion, and posterior digits were lost because all prospective digit precursors formed anterior structures. Inhibiting proliferation also irreversibly reduced anteroposterior expansion, but instead anterior digits were lost because all prospective digit precursors formed posterior structures. When proliferation recovered in such wings, Shh transcription was maintained for longer than normal, suggesting that duration of Shh expression is controlled by a mechanism that measures proliferation. Rescue experiments confirmed that Shh-dependent proliferation controls digit number during a discrete time-window in which Shh-dependent specification normally occurs. Our findings that Shh signalling has dual functions that can be temporally uncoupled have implications for understanding congenital and evolutionary digit reductions.
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Affiliation(s)
- Matthew Towers
- Division of Cell and Developmental Biology, WTB/MSI Complex, University of Dundee, Dow Street, Dundee DD1 5EH, UK
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33
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Sequential and cooperative action of Fgfs and Shh in the zebrafish retina. Dev Biol 2008; 314:200-14. [DOI: 10.1016/j.ydbio.2007.11.034] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2007] [Revised: 11/19/2007] [Accepted: 11/27/2007] [Indexed: 11/23/2022]
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Hedgehog pathway expression in heterogeneous pancreatic adenocarcinoma: implications for the molecular analysis of clinically available biopsies. ACTA ACUST UNITED AC 2008; 16:229-37. [PMID: 18043287 DOI: 10.1097/pdm.0b013e31811edc7e] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Recent studies suggest that hedgehog (HH)-pathway signaling is required for the initiation and continued growth of pancreatic adenocarcinoma (PAC). Definitive gene expression analysis of PAC remains difficult, owing to the host desmoplastic stromal interaction and subsequent tumor heterogeneity. The primary goal of this study was to evaluate the effect of heterogeneity within a series (n=5) of matched clinical PAC biopsies [snap-frozen, formalin-fixed paraffin-embedded (FPE), endoscopic ultrasound-guided fine-needle aspirate (EUS-FNA)]. Differential expressions, specific to tumor cells, were evaluated by comparisons of uninvolved pancreas (n=9), EUS-FNA (n=14), and macrodissected (tumor-cell-enriched) biopsies (n=16). To determine whether treatment modulates gene expression, a unique (independent) set of synchronous EUS-FNA samples (n=4) was obtained before, and 2 weeks after, chemoradiation. mRNA levels were evaluated using real-time quantitative polymerase chain reaction formatted in a TaqMan low-density array, which was capable of simultaneously quantifying 46 independent genes in the HH pathway. Protein levels for Patched, Smoothened, and glioma-associated oncogene 1 (Gli-1) in FPE tissues were determined, using immunohistochemistry. A significant concordance (P<0.0001) was observed in the HH-pathway mRNA levels between matched surgically resected (both snap-frozen and FPE) and EUS-FNA biopsies. HH-pathway mRNA levels changed (increased) only after macrodissection, suggesting localization to tumor cells. Immunohistochemical staining for Patched, Smoothened, and Gli-1 confirmed the increased (P<0.001) levels of protein in the PAC cells, compared with cells from uninvolved pancreas. EUS-FNA biopsies that were obtained before and during chemoradiation demonstrated no significant changes in HH-pathway gene expression. Collectively, these studies demonstrate presence of HH-pathway expression in all the clinical PAC biopsies examined, suggesting that this is a significant tumor-associated target and offering the possibility that specific molecular profiling might be attempted from these heterogeneous tissues.
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35
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Bayly RD, Ngo M, Aglyamova GV, Agarwala S. Regulation of ventral midbrain patterning by Hedgehog signaling. Development 2007; 134:2115-24. [PMID: 17507412 DOI: 10.1242/dev.02850] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In the developing ventral midbrain, the signaling molecule sonic hedgehog(SHH) is sufficient to specify a striped pattern of cell fates (midbrain arcs). Here, we asked whether and precisely how hedgehog (HH) signaling might be necessary for ventral midbrain patterning. By blocking HH signaling by in ovo misexpression of Ptc1Δloop2,we show that HH signaling is necessary and can act directly at a distance to specify midbrain cell fates. Ventral midbrain progenitors extinguish their dependence upon HH in a spatiotemporally complex manner, completing cell-fate specification at the periphery by Hamburger and Hamilton stage 13. Thus,patterning at the lateral periphery of the ventral midbrain is accomplished early, when the midbrain is small and the HH signal needs to travel relatively short distances (approximately 30 cell diameters). Interestingly, single-cell injections demonstrate that patterning in the midbrain occurs within the context of cortex-like radial columns of cells that can share HH blockade and are cytoplasmically connected by gap junctions. HH blockade results in increased cell scatter, disrupting the spatial coherence of the midbrain arc pattern. Finally, HH signaling is required for the integrity and the signaling properties of the boundaries of the midbrain (e.g. the midbrain-hindbrain boundary, the dorsoventral boundary), its perturbations resulting in abnormal cell mixing across `leaky' borders.
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Affiliation(s)
- Roy D Bayly
- Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712-0248, USA
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36
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Russell MC, Cowan RG, Harman RM, Walker AL, Quirk SM. The hedgehog signaling pathway in the mouse ovary. Biol Reprod 2007; 77:226-36. [PMID: 17392501 DOI: 10.1095/biolreprod.106.053629] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The hedgehog (HH) signaling pathway plays an essential role in the Drosophila ovary, regulating cell proliferation and differentiation, but a role in the mammalian ovary has not been defined. Expression of components of the HH pathway in the mouse ovary and effects of altering HH signaling in vitro were determined. RT-PCR analyses show developmentally regulated expression of sonic (Shh), indian (Ihh) and desert (Dhh) HH in the ovary. Expression is detected in whole ovary, granulosa cells, and corpora lutea. The mRNAs for the two receptors, patched homolog 1 and 2 (Ptch1, Ptch2), and the signal transducer, smoothened (Smo), are also expressed. Immunohistochemistry using an antibody that detects all three HH ligands demonstrated HH protein primarily in granulosa cells of follicles from primary to antral stages of development. Follicles also stained for PTCH1 and SMO in both granulosa and theca cells. Treatment of cultured preantral follicles and granulosa cells with recombinant SHH increased growth and proliferation while treatment with the HH pathway inhibitor, cyclopamine, had no effect. Therefore, activation of HH signaling can increase cell proliferation and follicle growth but is not essential for these processes in vitro. Treatment of granulosa cells with SHH increased levels of mRNA for Gli1, a transcriptional target of HH signaling, while cyclopamine decreased expression. SHH had no effect on production of progesterone by cultured granulosa cells, while cyclopamine increased progesterone production. The results demonstrate a functional HH pathway in the follicle and identify granulosa cells as at least one of the potential targets of HH signaling.
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Affiliation(s)
- Matthew C Russell
- Department of Animal Science, Cornell University, Ithaca, New York 14853, USA
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37
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Detmer K, Garner RE. Cell surface marker and cell cycle analysis, Hedgehog signaling, and flow cytometry. Methods Mol Biol 2007; 397:79-90. [PMID: 18025715 DOI: 10.1007/978-1-59745-516-9_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Detailed cytological analysis of cells undergoing differentiation often reveals clues to the regulation of multiple cell features. The Hedgehog (Hh) signaling cascade is a master regulator of cell fate during differentiation and is implicated in the development of some neoplasias. Hh signaling affects the expression of cell surface markers of differentiation. We have used the flow cytometer to evaluate the effect of blockage of the Hh signal on the expression of cell surface markers of erythroid differentiation in an in vitro system. In addition, the effect of Hh signaling on the distribution of cells in the phases of the cell cycle over the course of erythroid differentiation was assessed. Inhibition of the Hh signal retards progression of the erythroid developmental program. Included is a discussion of some of the basic parameters, limitations, and interpretations of flow cytometric analysis used for CD marker expression and cell cycle studies.
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38
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Locker M, Agathocleous M, Amato MA, Parain K, Harris WA, Perron M. Hedgehog signaling and the retina: insights into the mechanisms controlling the proliferative properties of neural precursors. Genes Dev 2006; 20:3036-48. [PMID: 17079690 PMCID: PMC1620016 DOI: 10.1101/gad.391106] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Hedgehog signaling has been linked to cell proliferation in a variety of systems; however, its effects on the cell cycle have not been closely studied. In the vertebrate retina, Hedgehog's effects are controversial, with some reports emphasizing increased proliferation and others pointing to a role in cell cycle exit. Here we demonstrate a novel role for Hedgehog signaling in speeding up the cell cycle in the developing retina by reducing the length of G1 and G2 phases. These fast cycling cells tend to exit the cell cycle early. Conversely, retinal progenitors with blocked Hedgehog signaling cycle more slowly, with longer G1 and G2 phases, and remain in the cell cycle longer. Hedgehog may modulate cell cycle kinetics through activation of the key cell cycle activators cyclin D1, cyclin A2, cyclin B1, and cdc25C. These findings support a role for Hedgehog in regulating the conversion from slow cycling stem cells to fast cycling transient amplifying progenitors that are closer to cell cycle exit.
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Affiliation(s)
- Morgane Locker
- Laboratoire Gènes, Développement et Neurogenèse, Université Paris XI, UMR Centre national de la Recherche Scientifique (CNRS) 8080, Orsay, France
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39
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Trowbridge JJ, Scott MP, Bhatia M. Hedgehog modulates cell cycle regulators in stem cells to control hematopoietic regeneration. Proc Natl Acad Sci U S A 2006; 103:14134-9. [PMID: 16968775 PMCID: PMC1599924 DOI: 10.1073/pnas.0604568103] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The signals that control the regenerative ability of hematopoietic stem cells (HSCs) in response to damage are unknown. Here, we demonstrate that downstream activation of the Hedgehog (Hh) signaling pathway induces cycling and expansion of primitive bone marrow hematopoietic cells under homeostatic conditions and during acute regeneration. However, this effect is at the expense of HSC function, because continued Hh activation during regeneration represses expression of specific cell cycle regulators, leading to HSC exhaustion. In vivo treatment with an inhibitor of the Hh pathway rescues these transcriptional and functional defects in HSCs. Our study establishes Hh signaling as a regulator of the HSC cell cycle machinery that balances hematopoietic homeostasis and regeneration in vivo.
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Affiliation(s)
- Jennifer J. Trowbridge
- *Department of Microbiology and Immunology, University of Western Ontario, 1151 Richmond Street, Suite 2, London, ON, Canada N6A 5B8
| | - Matthew P. Scott
- Departments of Biology, Genetics, and Bioengineering, Stanford University School of Medicine, Howard Hughes Medical Institute, Stanford, CA 94305-5439
| | - Mickie Bhatia
- *Department of Microbiology and Immunology, University of Western Ontario, 1151 Richmond Street, Suite 2, London, ON, Canada N6A 5B8
- McMaster Stem Cell and Cancer Research Institute, The Michael G. DeGroote School of Medicine, Hamilton, ON, Canada L9G 4L6; and
- Department of Biochemistry and Biomedical Sciences, McMaster University, 1200 Main Street West, Hamilton, ON, Canada L8N 3Z5
- To whom correspondence should be addressed. E-mail:
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Xu J, Srinivas BP, Tay SY, Mak A, Yu X, Lee SGP, Yang H, Govindarajan KR, Leong B, Bourque G, Mathavan S, Roy S. Genomewide expression profiling in the zebrafish embryo identifies target genes regulated by Hedgehog signaling during vertebrate development. Genetics 2006; 174:735-52. [PMID: 16888327 PMCID: PMC1602081 DOI: 10.1534/genetics.106.061523] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Hedgehog proteins play critical roles in organizing the embryonic development of animals, largely through modulation of target gene expression. Little is currently known, however, about the kinds and numbers of genes whose expression is controlled, directly or indirectly, by Hedgehog activity. Using techniques to globally repress or activate Hedgehog signaling in zebrafish embryos followed by microarray-based expression profiling, we have discovered a cohort of genes whose expression responds significantly to loss or gain of Hedgehog function. We have confirmed the Hedgehog responsiveness of a representative set of these genes with whole-mount in situ hybridization as well as real time PCR. In addition, we show that the consensus Gli-binding motif is enriched within the putative regulatory elements of a sizeable proportion of genes that showed positive regulation in our assay, indicating that their expression is directly induced by Hedgehog. Finally, we provide evidence that the Hedgehog-dependent spatially restricted transcription of one such gene, nkx2.9, is indeed mediated by Gli1 through a single Gli recognition site located within an evolutionarily conserved enhancer fragment. Taken together, this study represents the first comprehensive survey of target genes regulated by the Hedgehog pathway during vertebrate development. Our data also demonstrate for the first time the functionality of the Gli-binding motif in the control of Hedgehog signaling-induced gene expression in the zebrafish embryo.
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Affiliation(s)
- Jun Xu
- Institute of Molecular and Cell Biology, Singapore
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41
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Steg A, Wang W, Blanquicett C, Grunda JM, Eltoum IA, Wang K, Buchsbaum DJ, Vickers SM, Russo S, Diasio RB, Frost AR, LoBuglio AF, Grizzle WE, Johnson MR. Multiple gene expression analyses in paraffin-embedded tissues by TaqMan low-density array: Application to hedgehog and Wnt pathway analysis in ovarian endometrioid adenocarcinoma. J Mol Diagn 2006; 8:76-83. [PMID: 16436637 PMCID: PMC1867577 DOI: 10.2353/jmoldx.2006.040402] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Recent studies have shown the hedgehog and Wnt families of signaling proteins to be associated with tumor initiation, growth, and survival. However, these pathways remain unexplored in ovarian endometrioid adenocarcinoma (OEA). Here, we describe a novel TaqMan low-density array to examine the expression of 26 and 20 genes in the hedgehog and Wnt pathways, respectively, in six matched snap-frozen and formalin-fixed, paraffin-embedded (FPE) OEA specimens. Expression values were normalized to uninvolved ovarian epithelium. Gene expression in matched frozen and FPE tissues demonstrated significant concordance (r = 0.92, P < 0.0001). However, comparison of amplified and unamplified RNA from frozen OEA tissues revealed an altered molecular profile in amplified RNA. Amplification of RNA from FPE tissues was not successful. The expression of Desert hedgehog (DHH), Indian hedgehog (IHH), Hedge-hog interacting protein (HHIP), Wnt10B, Wnt9B, and Wnt inhibitory factor (WIF1) were tumor-specific with no detectable expression in normal ovarian epithelium. In addition, several genes were significantly (P < 0.025) down-regulated in OEA, including cyclin E2, Porcupine, c-Myc, and Axin 2 (4.8-, 3.6-, 2.9-, and 1.9-fold, respectively). TaqMan low-density array provides an effective multivariate technique for examining gene expression in RNA isolated from either snap-frozen or archival FPE tissues and can identify tumor-specific genes, possibly leading to novel treatments.
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Affiliation(s)
- Adam Steg
- Department of Clinical Pharmacology, University of Alabama at Birmingham, Birmingham, AL 34294-3300, USA
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Zhou JX, Jia LW, Liu WM, Miao CL, Liu S, Cao YJ, Duan EK. Role of sonic hedgehog in maintaining a pool of proliferating stem cells in the human fetal epidermis. Hum Reprod 2006; 21:1698-704. [PMID: 16571640 DOI: 10.1093/humrep/del086] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND The mammalian epidermis is maintained by the ongoing proliferation of a subpopulation of keratinocytes known as epidermal stem cells. Sonic hedgehog (Shh) can regulate morphogenesis of hair follicles and several types of skin cancer, but the effect of Shh on proliferation of human putative epidermal stem cells (HPESCs) is poorly understood. METHODS AND RESULTS We first found that Shh, its receptors Patched1 (Ptc1) as well as Smoothened (Smo) and its downstream transcription factor Gli-1 were expressed in the basal layer of human fetal epidermis and freshly sorted HPESCs. Next, treatment of HPESCs with media conditioned by Shh-N-expressing cells promoted cell proliferation, whereas inhibition of Shh by cyclopamine, a specific inhibitor of Shh signalling, had an opposite effect. Interestingly, the mitogenic effect of epidermal growth factor (EGF) on HPESCs was efficiently abolished by cyclopamine. Finally, bone morphogenetic protein 4 (BMP-4), a potential downstream effector of Shh signalling, increased HPESC proliferation in a concentration-dependent manner. CONCLUSIONS Shh is an important regulator of HPESC proliferation in the basal layer of human fetal epidermis and modulates the cell responsiveness to EGF, which will assist to unravel the mechanisms that regulate stem cell proliferation and neoplasia in the human epidermis.
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Affiliation(s)
- Jia-xi Zhou
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, People's Republic of China
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Jones C, Reifegerste R, Moses K. Characterization of Drosophila mini-me, a gene required for cell proliferation and survival. Genetics 2006; 173:793-808. [PMID: 16547096 PMCID: PMC1526529 DOI: 10.1534/genetics.106.056762] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In the developing Drosophila eye, the morphogenetic furrow is a developmental organizing center for patterning and cell proliferation. The furrow acts both to limit eye size and to coordinate the number of cells to the number of facets. Here we report the molecular and functional characterization of Drosophila mini-me (mnm), a potential regulator of cell proliferation and survival in the developing eye. We first identified mnm as a dominant modifier of hedgehog loss-of-function in the developing eye. We report that mnm encodes a conserved protein with zinc knuckle and RING finger domains. We show that mnm is dispensable for patterning of the eye disc, but required in the eye for normal cell proliferation and survival. We also show that mnm null mutant cells exhibit altered cell cycle profiles and contain excess nucleic acid. Moreover, mnm overexpression can induce cells to proliferate and incorporate BrdU. Thus, our data implicate mnm as a regulator of mitotic progression during the proliferative phase of eye development, possibly through the control of nucleic acid metabolism.
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Affiliation(s)
- Chonnettia Jones
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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Sjostrom SK, Finn G, Hahn WC, Rowitch DH, Kenney AM. The Cdk1 Complex Plays a Prime Role in Regulating N-Myc Phosphorylation and Turnover in Neural Precursors. Dev Cell 2005; 9:327-38. [PMID: 16139224 DOI: 10.1016/j.devcel.2005.07.014] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2005] [Revised: 04/23/2005] [Accepted: 07/28/2005] [Indexed: 12/23/2022]
Abstract
Myc family transcription factors are destabilized by phosphorylation of a conserved amino-terminal GSK-3beta motif. In proliferating cerebellar granule neuron precursors (CGNPs), Sonic hedgehog signaling induces N-myc expression, and N-myc protein is stabilized by insulin-like growth factor-mediated suppression of GSK-3beta. N-myc phosphorylation-mediated degradation is a prerequisite for CGNP growth arrest and differentiation. We investigated whether N-myc phosphorylation and turnover are thus linked to cell cycle exit in primary mouse CGNP cultures and the developing cerebellum. We report that phosphorylation-induced turnover of endogenous N-myc protein in CGNPs increases during mitosis, due to increased priming phosphorylation of N-myc for GSK-3beta. The priming phosphorylation requires the Cdk1 complex, whose cyclin subunits are indirect Sonic hedgehog targets. These findings provide a mechanism for promoting growth arrest in the final cycle of neural precursor proliferation competency, or for resetting the cell cycle in the G1 phase, by destabilizing N-myc in mitosis.
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Affiliation(s)
- Sarah K Sjostrom
- Department of Pediatric Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts 02115, USA
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Shkumatava A, Neumann CJ. Shh directs cell-cycle exit by activating p57Kip2 in the zebrafish retina. EMBO Rep 2005; 6:563-9. [PMID: 15891769 PMCID: PMC1369088 DOI: 10.1038/sj.embor.7400416] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2005] [Revised: 03/17/2005] [Accepted: 04/12/2005] [Indexed: 01/19/2023] Open
Abstract
The Hedgehog (Hh) family of signalling proteins control both differentiation and proliferation during animal development. Previous studies have shown that Hh signalling has a stimulatory effect on the cell cycle in several organs by controlling core cell-cycle components. Here, we show that Sonic hedgehog (Shh) signalling has the opposite effect in the zebrafish retina, where it leads to cell-cycle exit, and that this is mediated by transcriptional activation of the cyclin kinase inhibitor p57Kip2. The loss of p57Kip2 activity strongly resembles the Shh mutant eye phenotype, and overexpression of p57Kip2 rescues cell-cycle exit in Shh mutants, indicating that p57Kip2 is both necessary and sufficient to mediate Shh-induced cell-cycle exit in the retina. These findings raise the possibility that stimulation of cell-cycle exit through regulation of core cell-cycle components may be part of a general mechanism required for Hh-directed differentiation.
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Affiliation(s)
| | - Carl J. Neumann
- EMBL Heidelberg, Meyerhofstrasse 1, 69117 Heidelberg, Germany
- Tel: +49 6221 387 603; Fax: +49 6221 387 166; E-mail:
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Jaronczyk K, Carmichael J, Hobman T. Exploring the functions of RNA interference pathway proteins: some functions are more RISCy than others? Biochem J 2005; 387:561-71. [PMID: 15845026 PMCID: PMC1134985 DOI: 10.1042/bj20041822] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2004] [Revised: 12/23/2004] [Accepted: 02/22/2005] [Indexed: 01/21/2023]
Abstract
PPD (PAZ Piwi domain) proteins and the Dicer family have been the subjects of intense study over the last 6 years. These proteins have well-established roles in RNAi (RNA interference), a process that relies on siRNAs (small interfering RNAs) or miRNAs (microRNAs) to mediate specificity. The development of techniques for applying RNAi as a laboratory tool and a molecular therapeutic technique has rapidly outpaced our understanding of the biology of this process. However, over the last 2 years, great strides have been made towards elucidating how PPD proteins and Dicer regulate gene-silencing at the pre- and post-transcriptional levels. In addition, evidence is beginning to emerge that suggests that these proteins have additional siRNA-independent roles as cell-cycle regulators. In the present review, we summarize the well-known roles of these two classes of proteins in gene-silencing pathways, as well as explore the evidence for novel roles of PPD and Dicer proteins.
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Key Words
- dicer
- gene expression
- gene silencing
- paz piwi domain protein (ppd protein)
- rna-induced silencing complex (risc)
- rna interference (rnai)
- ds, double-stranded
- fxr, fragile x mental retardation protein
- gfp, green fluorescent protein
- mirna, microrna
- mirnp, mirna-containing ribonucleoprotein
- mvh, mammalian vasa homologue
- ppd, paz piwi domain
- risc, rna-induced silencing complex
- rits, rna-induced initiation of transcriptional gene silencing
- rnai, rna interference
- sirna, small interfering rna
- ss, single-stranded
- utr, untranslated region
- vig, vasa intronic gene protein
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Affiliation(s)
- Katarzyna Jaronczyk
- *Department of Cell Biology, University of Alberta, Edmonton, AB, Canada T6G 2H7
| | - Jon B. Carmichael
- *Department of Cell Biology, University of Alberta, Edmonton, AB, Canada T6G 2H7
| | - Tom C. Hobman
- *Department of Cell Biology, University of Alberta, Edmonton, AB, Canada T6G 2H7
- †Medical Microbiology and Immunology, University of Alberta, Edmonton, AB, Canada T6G 2H7
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Masai I, Yamaguchi M, Tonou-Fujimori N, Komori A, Okamoto H. The hedgehog-PKA pathway regulates two distinct steps of the differentiation of retinal ganglion cells: the cell-cycle exit of retinoblasts and their neuronal maturation. Development 2005; 132:1539-53. [PMID: 15728672 DOI: 10.1242/dev.01714] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In the developing zebrafish retina, neurogenesis is initiated in cells adjacent to the optic stalk and progresses to the entire neural retina. It has been reported that hedgehog (Hh) signalling mediates the progression of the differentiation of retinal ganglion cells (RGCs) in zebrafish. However, the progression of neurogenesis seems to be only mildly delayed by genetic or chemical blockade of the Hh signalling pathway. Here, we show that cAMP-dependent protein kinase (PKA) effectively inhibits the progression of retinal neurogenesis in zebrafish. Almost all retinal cells continue to proliferate when PKA is activated, suggesting that PKA inhibits the cell-cycle exit of retinoblasts. A cyclin-dependent kinase (cdk) inhibitor p27 inhibits the PKA-induced proliferation, suggesting that PKA functions upstream of cyclins and cdk inhibitors. Activation of the Wnt signalling pathway induces the hyperproliferation of retinal cells in zebrafish. The blockade of Wnt signalling inhibits the PKA-induced proliferation, but the activation of Wnt signalling promotes proliferation even in the absence of PKA activity. These observations suggest that PKA inhibits exit from the Wnt-mediated cell cycle rather than stimulates Wnt-mediated cell-cycle progression. PKA is an inhibitor of Hh signalling, and Hh signalling molecule morphants show severe defects in cell-cycle exit of retinoblasts. Together, these data suggest that Hh acts as a short-range signal to induce the cell-cycle exit of retinoblasts. The pulse inhibition of Hh signalling revealed that Hh signalling regulates at least two distinct steps of RGC differentiation: the cell-cycle exit of retinoblasts and RGC maturation. This dual requirement of Hh signalling in RGC differentiation implies that the regulation of a neurogenic wave is more complex in the zebrafish retina than in the Drosophila eye.
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Affiliation(s)
- Ichiro Masai
- Masai Initiative Research Unit, RIKEN (The Institute of Physical and Chemical Research, Hirosawa, Saitama, Japan.
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Reifenberger J. [Hereditary tumor syndromes. Cutaneous manifestations and molecular pathogenesis of Gorlin and Cowden syndromes]. Hautarzt 2004; 55:942-51. [PMID: 15349693 DOI: 10.1007/s00105-004-0800-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Several hereditary tumor syndromes are associated with characteristic skin lesions which may facilitate an early diagnosis. We summarize clinical features and recent progress in understanding the etiology and pathogenesis of two selected tumor syndromes, namely nevoid basal cell carcinoma syndrome (Gorlin syndrome) and Cowden syndrome. Both are autosomal dominantly inherited disorders. Nevoid basal cell carcinoma syndrome is characterized by the early onset of multiple basal cell carcinomas as as well as developmental defects and a predisposition for other benign and malignant tumors. The syndrome is caused by germline mutations in the PTCH tumor suppressor gene. Cowden syndrome is associated with pathognomonic mucocutaneous lesions, such as facial trichilemmomas, acral keratoses, and mucocutaneous papillomatosis. In addition, Cowden patients are predisposed to carcinomas of the thyroid, breast and endometrium. Cowden syndrome is caused by germline mutations in the PTEN tumor suppressor gene. Identification of the genes causing hereditary tumor syndromes as well as generation of genetically engineered mouse models have greatly advanced our understanding of the molecular pathogenesis of these diseases. Furthermore, novel pathogenesis-based pharmacological strategies are being developed that promise to improve prevention and therapy.
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Shah DK, Hager-Theodorides AL, Outram SV, Ross SE, Varas A, Crompton T. Reduced thymocyte development in sonic hedgehog knockout embryos. THE JOURNAL OF IMMUNOLOGY 2004; 172:2296-306. [PMID: 14764698 DOI: 10.4049/jimmunol.172.4.2296] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The Hedgehog family of secreted intercellular signaling molecules are regulators of patterning and organogenesis during animal development. In this study we provide genetic evidence that Sonic Hedgehog (Shh) has a role in the control of murine T cell development. Analysis of Shh(-/-) mouse embryos revealed that Shh regulates fetal thymus cellularity and thymocyte differentiation. Shh is necessary for expansion of CD4(-)CD8(-) double-negative (DN) thymocytes and for efficient transition from the earliest CD44(+)CD25(-) DN population to the subsequent CD44(+)CD25(+) DN population and from DN to CD4(+)CD8(+) double-positive cells.
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Affiliation(s)
- Divya K Shah
- Department of Biological Sciences, Imperial College London, London, United Kingdom
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