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Gong GQ, Bilanges B, Allsop B, Masson GR, Roberton V, Askwith T, Oxenford S, Madsen RR, Conduit SE, Bellini D, Fitzek M, Collier M, Najam O, He Z, Wahab B, McLaughlin SH, Chan AWE, Feierberg I, Madin A, Morelli D, Bhamra A, Vinciauskaite V, Anderson KE, Surinova S, Pinotsis N, Lopez-Guadamillas E, Wilcox M, Hooper A, Patel C, Whitehead MA, Bunney TD, Stephens LR, Hawkins PT, Katan M, Yellon DM, Davidson SM, Smith DM, Phillips JB, Angell R, Williams RL, Vanhaesebroeck B. A small-molecule PI3Kα activator for cardioprotection and neuroregeneration. Nature 2023; 618:159-168. [PMID: 37225977 PMCID: PMC7614683 DOI: 10.1038/s41586-023-05972-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 03/17/2023] [Indexed: 05/26/2023]
Abstract
Harnessing the potential beneficial effects of kinase signalling through the generation of direct kinase activators remains an underexplored area of drug development1-5. This also applies to the PI3K signalling pathway, which has been extensively targeted by inhibitors for conditions with PI3K overactivation, such as cancer and immune dysregulation. Here we report the discovery of UCL-TRO-1938 (referred to as 1938 hereon), a small-molecule activator of the PI3Kα isoform, a crucial effector of growth factor signalling. 1938 allosterically activates PI3Kα through a distinct mechanism by enhancing multiple steps of the PI3Kα catalytic cycle and causes both local and global conformational changes in the PI3Kα structure. This compound is selective for PI3Kα over other PI3K isoforms and multiple protein and lipid kinases. It transiently activates PI3K signalling in all rodent and human cells tested, resulting in cellular responses such as proliferation and neurite outgrowth. In rodent models, acute treatment with 1938 provides cardioprotection from ischaemia-reperfusion injury and, after local administration, enhances nerve regeneration following nerve crush. This study identifies a chemical tool to directly probe the PI3Kα signalling pathway and a new approach to modulate PI3K activity, widening the therapeutic potential of targeting these enzymes through short-term activation for tissue protection and regeneration. Our findings illustrate the potential of activating kinases for therapeutic benefit, a currently largely untapped area of drug development.
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Affiliation(s)
- Grace Q Gong
- Cell Signalling, Cancer Institute, University College London, London, UK
| | - Benoit Bilanges
- Cell Signalling, Cancer Institute, University College London, London, UK
| | - Ben Allsop
- Drug Discovery Group, Translational Research Office, University College London, London, UK
| | - Glenn R Masson
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
- Division of Cellular Medicine, School of Medicine, University of Dundee, Dundee, UK
| | - Victoria Roberton
- UCL Centre for Nerve Engineering, UCL School of Pharmacy, University College London, London, UK
| | - Trevor Askwith
- Drug Discovery Group, Translational Research Office, University College London, London, UK
| | - Sally Oxenford
- Drug Discovery Group, Translational Research Office, University College London, London, UK
| | - Ralitsa R Madsen
- Cell Signalling, Cancer Institute, University College London, London, UK
| | - Sarah E Conduit
- Cell Signalling, Cancer Institute, University College London, London, UK
| | - Dom Bellini
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Martina Fitzek
- Hit Discovery, Discovery Sciences, R&D, AstraZeneca, Alderley Park, Macclesfield, UK
| | - Matt Collier
- Hit Discovery, Discovery Sciences, R&D, AstraZeneca, Alderley Park, Macclesfield, UK
| | - Osman Najam
- The Hatter Cardiovascular Institute, University College London, London, UK
| | - Zhenhe He
- The Hatter Cardiovascular Institute, University College London, London, UK
| | - Ben Wahab
- Medicines Discovery Institute, School of Biosciences, Cardiff University, Cardiff, UK
| | | | - A W Edith Chan
- Wolfson Institute for Biomedical Research, University College London, London, UK
| | | | - Andrew Madin
- Hit Discovery, Discovery Sciences, R&D, AstraZeneca, Cambridge, UK
| | - Daniele Morelli
- Cell Signalling, Cancer Institute, University College London, London, UK
| | - Amandeep Bhamra
- Proteomics Research Translational Technology Platform, Cancer Institute, University College London, London, UK
| | - Vanesa Vinciauskaite
- Division of Cellular Medicine, School of Medicine, University of Dundee, Dundee, UK
| | | | - Silvia Surinova
- Proteomics Research Translational Technology Platform, Cancer Institute, University College London, London, UK
| | - Nikos Pinotsis
- Institute of Structural and Molecular Biology, Birkbeck College, London, UK
| | | | - Matthew Wilcox
- UCL Centre for Nerve Engineering, UCL School of Pharmacy, University College London, London, UK
| | - Alice Hooper
- Drug Discovery Group, Translational Research Office, University College London, London, UK
| | - Chandni Patel
- Drug Discovery Group, Translational Research Office, University College London, London, UK
| | - Maria A Whitehead
- Cell Signalling, Cancer Institute, University College London, London, UK
| | - Tom D Bunney
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, UK
| | | | | | - Matilda Katan
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, UK
| | - Derek M Yellon
- The Hatter Cardiovascular Institute, University College London, London, UK
| | - Sean M Davidson
- The Hatter Cardiovascular Institute, University College London, London, UK
| | - David M Smith
- Emerging Innovations, Discovery Sciences, R&D, AstraZeneca, Cambridge, UK
| | - James B Phillips
- UCL Centre for Nerve Engineering, UCL School of Pharmacy, University College London, London, UK
| | - Richard Angell
- Drug Discovery Group, Translational Research Office, University College London, London, UK
- Medicines Discovery Institute, School of Biosciences, Cardiff University, Cardiff, UK
| | - Roger L Williams
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
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Alliouachene S, Kieswich JE, Bilanges B, McCafferty K, Thiemermann C, Vanhaesebroeck B, Yaqoob MM. Uninephrectomy and class II PI3K-C2β inactivation synergistically protect against obesity, insulin resistance and liver steatosis in mice. Am J Transplant 2021; 21:2688-2697. [PMID: 33370494 DOI: 10.1111/ajt.16470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 12/21/2020] [Accepted: 12/21/2020] [Indexed: 01/25/2023]
Abstract
Uninephrectomy (UNx) in living kidney donors for transplantation is now routine clinical practice. While chronic kidney disease, due to bilateral kidney dysfunction, is associated with insulin resistance, liver steatosis, and type 2 diabetes, the metabolic impact of UNx remains unclear. To better understand the crosstalk between the kidney and insulin target tissues, we studied the metabolic consequences of UNx and the potential involvement of class II PI3K-C2β, the inactivation of which has been reported to result in insulin sensitization. Mice underwent UNx or sham operation followed by either normal chow or high-fat diet (HFD). Seventeen weeks post-UNx, mice showed improved glucose tolerance, insulin sensitivity, and decreased HFD-induced liver steatosis. This was associated with an enhanced serum FGF21 and insulin-stimulated Akt signaling in the liver and muscle of both lean and obese mice. Remarkably, the combination of UNx and PI3K-C2β inactivation protected against HFD-induced obesity and further potentiated the metabolic improvement observed in WT UNx mice correlating with a synergistic increase in metabolic tissues of (1) insulin-stimulated Akt signaling (2) FGFR1 and βKlotho expression. We demonstrated a potential beneficial effect of kidney donation and more effectively with PI3K-C2β inactivation to protect against metabolic disorders through a mutual insulin/FGF21 sensitization.
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Affiliation(s)
- Samira Alliouachene
- Centre for Translational Medicine and Therapeutics, William Harvey Research Institute, Queen Mary University of London, London, UK
| | - Julius E Kieswich
- Centre for Translational Medicine and Therapeutics, William Harvey Research Institute, Queen Mary University of London, London, UK
| | | | - Kieran McCafferty
- Centre for Translational Medicine and Therapeutics, William Harvey Research Institute, Queen Mary University of London, London, UK
| | - Christoph Thiemermann
- Centre for Translational Medicine and Therapeutics, William Harvey Research Institute, Queen Mary University of London, London, UK
| | | | - Muhammad M Yaqoob
- Centre for Translational Medicine and Therapeutics, William Harvey Research Institute, Queen Mary University of London, London, UK
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Abstract
PI3Ks are a family of lipid kinases that phosphorylate intracellular inositol lipids to regulate signalling and intracellular vesicular traffic. Mammals have eight isoforms of PI3K, divided into three classes. The class I PI3Ks generate 3-phosphoinositide lipids, which directly activate signal transduction pathways. In addition to being frequently genetically activated in cancer, similar mutations in class I PI3Ks have now also been found in a human non-malignant overgrowth syndrome and a primary immune disorder that predisposes to lymphoma. The class II and class III PI3Ks are regulators of membrane traffic along the endocytic route, in endosomal recycling and autophagy, with an often indirect effect on cell signalling. Here, we summarize current knowledge of the different PI3K classes and isoforms, focusing on recently uncovered biological functions and the mechanisms by which these kinases are activated. Deeper insight into the PI3K isoforms will undoubtedly continue to contribute to a better understanding of fundamental cell biological processes and, ultimately, of human disease.
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Affiliation(s)
- Benoit Bilanges
- UCL Cancer Institute, University College London, London, UK.
| | - York Posor
- UCL Cancer Institute, University College London, London, UK.
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4
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Vanhaesebroeck B, Bilanges B, Madsen RR, Dale KL, Lau E, Vladimirou E. Perspective: Potential Impact and Therapeutic Implications of Oncogenic PI3K Activation on Chromosomal Instability. Biomolecules 2019; 9:E331. [PMID: 31374965 PMCID: PMC6723836 DOI: 10.3390/biom9080331] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 07/30/2019] [Accepted: 07/31/2019] [Indexed: 01/01/2023] Open
Abstract
Genetic activation of the class I PI3K pathway is very common in cancer. This mostly results from oncogenic mutations in PIK3CA, the gene encoding the ubiquitously expressed PI3Kα catalytic subunit, or from inactivation of the PTEN tumour suppressor, a lipid phosphatase that opposes class I PI3K signalling. The clinical impact of PI3K inhibitors in solid tumours, aimed at dampening cancer-cell-intrinsic PI3K activity, has thus far been limited. Challenges include poor drug tolerance, incomplete pathway inhibition and pre-existing or inhibitor-induced resistance. The principle of pharmacologically targeting cancer-cell-intrinsic PI3K activity also assumes that all cancer-promoting effects of PI3K activation are reversible, which might not be the case. Emerging evidence suggests that genetic PI3K pathway activation can induce and/or allow cells to tolerate chromosomal instability, which-even if occurring in a low fraction of the cell population-might help to facilitate and/or drive tumour evolution. While it is clear that such genomic events cannot be reverted pharmacologically, a role for PI3K in the regulation of chromosomal instability could be exploited by using PI3K pathway inhibitors to prevent those genomic events from happening and/or reduce the pace at which they are occurring, thereby dampening cancer development or progression. Such an impact might be most effective in tumours with clonal PI3K activation and achievable at lower drug doses than the maximum-tolerated doses of PI3K inhibitors currently used in the clinic.
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Affiliation(s)
- Bart Vanhaesebroeck
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6BT, UK.
| | - Benoit Bilanges
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6BT, UK
| | - Ralitsa R Madsen
- Centre for Cardiovascular Sciences, Queens Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - Katie L Dale
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6BT, UK
| | - Evelyn Lau
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6BT, UK
| | - Elina Vladimirou
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6BT, UK.
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Bilanges B, Alliouachene S, Pearce W, Morelli D, Szabadkai G, Chung YL, Chicanne G, Valet C, Hill JM, Voshol PJ, Collinson L, Peddie C, Ali K, Ghazaly E, Rajeeve V, Trichas G, Srinivas S, Chaussade C, Salamon RS, Backer JM, Scudamore CL, Whitehead MA, Keaney EP, Murphy LO, Semple RK, Payrastre B, Tooze SA, Vanhaesebroeck B. Vps34 PI 3-kinase inactivation enhances insulin sensitivity through reprogramming of mitochondrial metabolism. Nat Commun 2017; 8:1804. [PMID: 29180704 PMCID: PMC5703854 DOI: 10.1038/s41467-017-01969-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 10/30/2017] [Indexed: 12/13/2022] Open
Abstract
Vps34 PI3K is thought to be the main producer of phosphatidylinositol-3-monophosphate, a lipid that controls intracellular vesicular trafficking. The organismal impact of systemic inhibition of Vps34 kinase activity is not completely understood. Here we show that heterozygous Vps34 kinase-dead mice are healthy and display a robustly enhanced insulin sensitivity and glucose tolerance, phenotypes mimicked by a selective Vps34 inhibitor in wild-type mice. The underlying mechanism of insulin sensitization is multifactorial and not through the canonical insulin/Akt pathway. Vps34 inhibition alters cellular energy metabolism, activating the AMPK pathway in liver and muscle. In liver, Vps34 inactivation mildly dampens autophagy, limiting substrate availability for mitochondrial respiration and reducing gluconeogenesis. In muscle, Vps34 inactivation triggers a metabolic switch from oxidative phosphorylation towards glycolysis and enhanced glucose uptake. Our study identifies Vps34 as a new drug target for insulin resistance in Type-2 diabetes, in which the unmet therapeutic need remains substantial.
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Affiliation(s)
- Benoit Bilanges
- UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK.
| | - Samira Alliouachene
- UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK
| | - Wayne Pearce
- UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK
| | - Daniele Morelli
- UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK
| | - Gyorgy Szabadkai
- Department of Cell and Developmental Biology, Consortium for Mitochondrial Research, University College London, Gower Street, London, WC1E 6BT, UK
- Department of Biomedical Sciences, University of Padua, Padua, 58/B via Ugo, Bassi, 35121, Italy
| | - Yuen-Li Chung
- Cancer Research UK Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research London, 123 Old Brompton Road, London, SW7 3RP, UK
| | - Gaëtan Chicanne
- Inserm/UPS UMR 1048, Institut des Maladies Métaboliques et Cardiovasculaires, 1 Avenue Jean Poulhès BP 84225, 31432, Toulouse Cedex 4, France
| | - Colin Valet
- Inserm/UPS UMR 1048, Institut des Maladies Métaboliques et Cardiovasculaires, 1 Avenue Jean Poulhès BP 84225, 31432, Toulouse Cedex 4, France
| | - Julia M Hill
- Department of Cell and Developmental Biology, Consortium for Mitochondrial Research, University College London, Gower Street, London, WC1E 6BT, UK
| | - Peter J Voshol
- Metabolic Research Laboratories, MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science, Level 4, Box 289, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
| | - Lucy Collinson
- The Francis Crick Institute, Lincoln's Inn Fields Laboratories, 44 Lincoln's Inn Fields, London, WC2A 3LY, UK
| | - Christopher Peddie
- The Francis Crick Institute, Lincoln's Inn Fields Laboratories, 44 Lincoln's Inn Fields, London, WC2A 3LY, UK
| | - Khaled Ali
- UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK
| | - Essam Ghazaly
- Centre of Haemato-Oncology, Barts Cancer Institute, Queen Mary University of London, London, EC1M 6BQ, UK
| | - Vinothini Rajeeve
- Centre of Haemato-Oncology, Barts Cancer Institute, Queen Mary University of London, London, EC1M 6BQ, UK
| | - Georgios Trichas
- Department of Physiology Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, UK
| | - Shankar Srinivas
- Department of Physiology Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, UK
| | - Claire Chaussade
- UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK
| | - Rachel S Salamon
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, 10461, NY, USA
| | - Jonathan M Backer
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, 10461, NY, USA
| | - Cheryl L Scudamore
- Mary Lyon Centre, MRC Harwell, Harwell Science and Innovation Campus, Harwell, OX11 0RD, UK
| | - Maria A Whitehead
- UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK
| | - Erin P Keaney
- Novartis Institutes for BioMedical Research, 181 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Leon O Murphy
- Novartis Institutes for BioMedical Research, 181 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Robert K Semple
- Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
| | - Bernard Payrastre
- Inserm/UPS UMR 1048, Institut des Maladies Métaboliques et Cardiovasculaires, 1 Avenue Jean Poulhès BP 84225, 31432, Toulouse Cedex 4, France
| | - Sharon A Tooze
- The Francis Crick Institute, Lincoln's Inn Fields Laboratories, 44 Lincoln's Inn Fields, London, WC2A 3LY, UK
| | - Bart Vanhaesebroeck
- UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK.
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Varrault A, Dantec C, Le Digarcher A, Chotard L, Bilanges B, Parrinello H, Dubois E, Rialle S, Severac D, Bouschet T, Journot L. Identification of Plagl1/Zac1 binding sites and target genes establishes its role in the regulation of extracellular matrix genes and the imprinted gene network. Nucleic Acids Res 2017; 45:10466-10480. [PMID: 28985358 PMCID: PMC5737700 DOI: 10.1093/nar/gkx672] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Revised: 06/29/2017] [Accepted: 07/20/2017] [Indexed: 01/05/2023] Open
Abstract
PLAGL1/ZAC1 undergoes parental genomic imprinting, is paternally expressed, and is a member of the imprinted gene network (IGN). It encodes a zinc finger transcription factor with anti-proliferative activity and is a candidate tumor suppressor gene on 6q24 whose expression is frequently lost in various neoplasms. Conversely, gain of PLAGL1 function is responsible for transient neonatal diabetes mellitus, a rare genetic disease that results from defective pancreas development. In the present work, we showed that Plagl1 up-regulation was not associated with DNA damage-induced cell cycle arrest. It was rather associated with physiological cell cycle exit that occurred with contact inhibition, growth factor withdrawal, or cell differentiation. To gain insights into Plagl1 mechanism of action, we identified Plagl1 target genes by combining chromatin immunoprecipitation and genome-wide transcriptomics in transfected cell lines. Plagl1-elicited gene regulation correlated with multiple binding to the proximal promoter region through a GC-rich motif. Plagl1 target genes included numerous genes involved in signaling, cell adhesion, and extracellular matrix composition, including collagens. Plagl1 targets also included 22% of the 409 genes that make up the IGN. Altogether, this work identified Plagl1 as a transcription factor that coordinated the regulation of a subset of IGN genes and controlled extracellular matrix composition.
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Affiliation(s)
- Annie Varrault
- Institut de Génomique Fonctionnelle, IGF, CNRS, INSERM, Univ. Montpellier, F-34094 Montpellier, France
| | - Christelle Dantec
- Montpellier GenomiX, MGX, BioCampus Montpellier, CNRS, INSERM, Univ. Montpellier, F-34094 Montpellier, France
| | - Anne Le Digarcher
- Institut de Génomique Fonctionnelle, IGF, CNRS, INSERM, Univ. Montpellier, F-34094 Montpellier, France
| | - Laëtitia Chotard
- Institut de Génomique Fonctionnelle, IGF, CNRS, INSERM, Univ. Montpellier, F-34094 Montpellier, France
| | - Benoit Bilanges
- Institut de Génomique Fonctionnelle, IGF, CNRS, INSERM, Univ. Montpellier, F-34094 Montpellier, France
| | - Hugues Parrinello
- Montpellier GenomiX, MGX, BioCampus Montpellier, CNRS, INSERM, Univ. Montpellier, F-34094 Montpellier, France
| | - Emeric Dubois
- Montpellier GenomiX, MGX, BioCampus Montpellier, CNRS, INSERM, Univ. Montpellier, F-34094 Montpellier, France
| | - Stéphanie Rialle
- Montpellier GenomiX, MGX, BioCampus Montpellier, CNRS, INSERM, Univ. Montpellier, F-34094 Montpellier, France
| | - Dany Severac
- Montpellier GenomiX, MGX, BioCampus Montpellier, CNRS, INSERM, Univ. Montpellier, F-34094 Montpellier, France
| | - Tristan Bouschet
- Institut de Génomique Fonctionnelle, IGF, CNRS, INSERM, Univ. Montpellier, F-34094 Montpellier, France
| | - Laurent Journot
- Institut de Génomique Fonctionnelle, IGF, CNRS, INSERM, Univ. Montpellier, F-34094 Montpellier, France
- Montpellier GenomiX, MGX, BioCampus Montpellier, CNRS, INSERM, Univ. Montpellier, F-34094 Montpellier, France
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7
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Alliouachene S, Bilanges B, Chaussade C, Pearce W, Foukas LC, Scudamore CL, Moniz LS, Vanhaesebroeck B. Inactivation of class II PI3K-C2α induces leptin resistance, age-dependent insulin resistance and obesity in male mice. Diabetologia 2016; 59:1503-1512. [PMID: 27138914 PMCID: PMC4901096 DOI: 10.1007/s00125-016-3963-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 03/24/2016] [Indexed: 01/08/2023]
Abstract
AIMS/HYPOTHESIS While the class I phosphoinositide 3-kinases (PI3Ks) are well-documented positive regulators of metabolism, the involvement of class II PI3K isoforms (PI3K-C2α, -C2β and -C2γ) in metabolic regulation is just emerging. Organismal inactivation of PI3K-C2β increases insulin signalling and sensitivity, whereas PI3K-C2γ inactivation has a negative metabolic impact. In contrast, the role of PI3K-C2α in organismal metabolism remains unexplored. In this study, we investigated whether kinase inactivation of PI3K-C2α affects glucose metabolism in mice. METHODS We have generated and characterised a mouse line with a constitutive inactivating knock-in (KI) mutation in the kinase domain of the gene encoding PI3K-C2α (Pik3c2a). RESULTS While homozygosity for kinase-dead PI3K-C2α was embryonic lethal, heterozygous PI3K-C2α KI mice were viable and fertile, with no significant histopathological findings. However, male heterozygous mice showed early onset leptin resistance, with a defect in leptin signalling in the hypothalamus, correlating with a mild, age-dependent obesity, insulin resistance and glucose intolerance. Insulin signalling was unaffected in insulin target tissues of PI3K-C2α KI mice, in contrast to previous reports in which downregulation of PI3K-C2α in cell lines was shown to dampen insulin signalling. Interestingly, no metabolic phenotypes were detected in female PI3K-C2α KI mice at any age. CONCLUSIONS/INTERPRETATION Our data uncover a sex-dependent role for PI3K-C2α in the modulation of hypothalamic leptin action and systemic glucose homeostasis. ACCESS TO RESEARCH MATERIALS All reagents are available upon request.
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Affiliation(s)
- Samira Alliouachene
- UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK.
| | - Benoit Bilanges
- UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK.
| | - Claire Chaussade
- UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK
- Galderma R&D, Sophia Antipolis Cedex, France
| | - Wayne Pearce
- UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK
| | - Lazaros C Foukas
- Institute of Healthy Ageing and Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Cheryl L Scudamore
- Mary Lyon Centre, MRC Harwell, Harwell Science and Innovation Campus, Harwell, UK
| | - Larissa S Moniz
- UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK
| | - Bart Vanhaesebroeck
- UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK.
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8
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Alliouachene S, Bilanges B, Chicanne G, Anderson KE, Pearce W, Ali K, Valet C, Posor Y, Low PC, Chaussade C, Scudamore CL, Salamon RS, Backer JM, Stephens L, Hawkins PT, Payrastre B, Vanhaesebroeck B. Inactivation of the Class II PI3K-C2β Potentiates Insulin Signaling and Sensitivity. Cell Rep 2015; 13:1881-94. [PMID: 26655903 PMCID: PMC4675724 DOI: 10.1016/j.celrep.2015.10.052] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 08/25/2015] [Accepted: 10/15/2015] [Indexed: 11/24/2022] Open
Abstract
In contrast to the class I phosphoinositide 3-kinases (PI3Ks), the organismal roles of the kinase activity of the class II PI3Ks are less clear. Here, we report that class II PI3K-C2β kinase-dead mice are viable and healthy but display an unanticipated enhanced insulin sensitivity and glucose tolerance, as well as protection against high-fat-diet-induced liver steatosis. Despite having a broad tissue distribution, systemic PI3K-C2β inhibition selectively enhances insulin signaling only in metabolic tissues. In a primary hepatocyte model, basal PI3P lipid levels are reduced by 60% upon PI3K-C2β inhibition. This results in an expansion of the very early APPL1-positive endosomal compartment and altered insulin receptor trafficking, correlating with an amplification of insulin-induced, class I PI3K-dependent Akt signaling, without impacting MAPK activity. These data reveal PI3K-C2β as a critical regulator of endosomal trafficking, specifically in insulin signaling, and identify PI3K-C2β as a potential drug target for insulin sensitization.
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Affiliation(s)
- Samira Alliouachene
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, UK.
| | - Benoit Bilanges
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, UK
| | - Gaëtan Chicanne
- Inserm/UPS UMR 1048, Institut des Maladies Métaboliques et Cardiovasculaires, 1 Avenue Jean Poulhès BP 84225, 31432 Toulouse Cedex 4, France
| | - Karen E Anderson
- Inositide Laboratory, The Babraham Institute, Cambridge CB22 3AT, UK
| | - Wayne Pearce
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, UK
| | - Khaled Ali
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, UK
| | - Colin Valet
- Inserm/UPS UMR 1048, Institut des Maladies Métaboliques et Cardiovasculaires, 1 Avenue Jean Poulhès BP 84225, 31432 Toulouse Cedex 4, France
| | - York Posor
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, UK
| | - Pei Ching Low
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, UK
| | - Claire Chaussade
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, UK
| | - Cheryl L Scudamore
- Mary Lyon Centre, MRC Harwell, Harwell Science and Innovation Campus, Harwell OX11 0RD, UK
| | - Rachel S Salamon
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Jonathan M Backer
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Len Stephens
- Inositide Laboratory, The Babraham Institute, Cambridge CB22 3AT, UK
| | - Phill T Hawkins
- Inositide Laboratory, The Babraham Institute, Cambridge CB22 3AT, UK
| | - Bernard Payrastre
- Inserm/UPS UMR 1048, Institut des Maladies Métaboliques et Cardiovasculaires, 1 Avenue Jean Poulhès BP 84225, 31432 Toulouse Cedex 4, France
| | - Bart Vanhaesebroeck
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, UK.
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9
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Abstract
Class II/III PI3Ks (phosphoinositide 3-kinases) produce the PtdIns(3)P lipid that is involved in intracellular vesicular trafficking. In contrast with class I PI3Ks, the potential signalling roles of class II/III PI3Ks are poorly understood. In a recent article in the Biochemical Journal, Bago and co-workers report that Vps34 (vacuolar protein sorting 34), the only class III PI3K, controls the activity of SGK3 (serum- and glucocorticoid-regulated protein kinase 3). Like other AGC kinases, the SGKs (SGK1, SGK2 and SGK3) are activated by dual phosphorylation. Unlike its cousins SGK1 and SGK2, SGK3 contains a PtdIns(3)P-binding domain, providing an additional element of regulation. The study by Bago et al. characterizes and makes extensive use of a Novartis Vps34 inhibitor (VPS34-IN1) that inhibits this PI3K isoform with nanomolar potency, without affecting other lipid kinases or more than 300 protein kinases. The authors show that this compound very rapidly reduced PtdIns(3)P levels at the endosome with concomitant loss of SGK3 phosphorylation. Co-inhibition of class I PI3Ks led to a further reduction in SGK3 activity, indicating that class I PI3Ks may also regulate SGK3 activity through an additional, currently unknown, mechanism. It remains to be assessed whether the novel PI3K-protein kinase connection established by this study is subject to acute cellular stimulation or is part of a constitutive housekeeping function. VPS34-IN1 will provide a useful tool to decipher the kinase-dependent functions of Vps34, with acute changes in SGK3 phosphorylation and subcellular localization being new biomarkers of Vps34 activity.
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Affiliation(s)
- Benoit Bilanges
- *UCL Cancer Institute, Paul O'Gorman Building University College London, 72 Huntley Street, London WC1E 6BT, U.K
| | - Bart Vanhaesebroeck
- *UCL Cancer Institute, Paul O'Gorman Building University College London, 72 Huntley Street, London WC1E 6BT, U.K
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10
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Casado P, Bilanges B, Rajeeve V, Vanhaesebroeck B, Cutillas PR. Environmental stress affects the activity of metabolic and growth factor signaling networks and induces autophagy markers in MCF7 breast cancer cells. Mol Cell Proteomics 2014; 13:836-48. [PMID: 24425749 PMCID: PMC3945912 DOI: 10.1074/mcp.m113.034751] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Revised: 12/13/2013] [Indexed: 11/06/2022] Open
Abstract
Phosphoproteomic techniques are contributing to our understanding of how signaling pathways interact and regulate biological processes. This technology is also being used to characterize how signaling networks are remodeled during disease progression and to identify biomarkers of signaling pathway activity and of responses to cancer therapy. A potential caveat in these studies is that phosphorylation is a very dynamic modification that can substantially change during the course of an experiment or the retrieval and processing of cellular samples. Here, we investigated how exposure of cells to ambient conditions modulates phosphorylation and signaling pathway activity in the MCF7 breast cancer cell line. About 1.5% of 3,500 sites measured showed a significant change in phosphorylation extent upon exposure of cells to ambient conditions for 15 min. The effects of this perturbation in modifying phosphorylation patterns did not involve random changes due to stochastic activation of kinases and phosphatases. Instead, exposure of cells to ambient conditions elicited an environmental stress reaction that involved a coordinated response to a metabolic stress situation, which included: (1) the activation of AMPK; (2) the inhibition of PI3K, AKT, and ERK; (3) an increase in markers of protein synthesis inhibition at the level of translation elongation; and (4) an increase in autophagy markers. We also observed that maintaining cells in ice modified but did not completely abolish this metabolic stress response. In summary, exposure of cells to ambient conditions affects the activity of signaling networks previously implicated in metabolic and growth factor signaling. Mass spectrometry data have been deposited to the ProteomeXchange with identifier PXD000472.
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Affiliation(s)
- Pedro Casado
- From the ‡Analytical Signalling Group and
- ¶ Current affiliation: Integrative Cell Signaling and Proteomics Group, Centre for Haemato-Oncology, Barts Cancer Institute, Queen Mary University of London, Barts and the London School of Medicine and Dentistry
| | - Benoit Bilanges
- §Cell Signalling Group, Centre for Cell Signalling, Barts Cancer Institute, Queen Mary University of London, Barts and the London School of Medicine and Dentistry, London EC1B 6BQ, UK
| | - Vinothini Rajeeve
- From the ‡Analytical Signalling Group and
- ¶ Current affiliation: Integrative Cell Signaling and Proteomics Group, Centre for Haemato-Oncology, Barts Cancer Institute, Queen Mary University of London, Barts and the London School of Medicine and Dentistry
| | - Bart Vanhaesebroeck
- §Cell Signalling Group, Centre for Cell Signalling, Barts Cancer Institute, Queen Mary University of London, Barts and the London School of Medicine and Dentistry, London EC1B 6BQ, UK
| | - Pedro R. Cutillas
- From the ‡Analytical Signalling Group and
- ¶ Current affiliation: Integrative Cell Signaling and Proteomics Group, Centre for Haemato-Oncology, Barts Cancer Institute, Queen Mary University of London, Barts and the London School of Medicine and Dentistry
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11
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Foukas LC, Bilanges B, Bettedi L, Pearce W, Ali K, Sancho S, Withers DJ, Vanhaesebroeck B. Long-term p110α PI3K inactivation exerts a beneficial effect on metabolism. EMBO Mol Med 2013; 5:563-71. [PMID: 23483710 PMCID: PMC3628103 DOI: 10.1002/emmm.201201953] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 01/03/2013] [Accepted: 01/07/2013] [Indexed: 11/07/2022] Open
Abstract
The insulin/insulin-like growth factor-1 signalling (IIS) pathway regulates cellular and organismal metabolism and controls the rate of aging. Gain-of-function mutations in p110α, the principal mammalian IIS-responsive isoform of PI 3-kinase (PI3K), promote cancer. In contrast, loss-of-function mutations in p110α impair insulin signalling and cause insulin resistance, inducing a pre-diabetic state. It remains unknown if long-term p110α inactivation induces further metabolic deterioration over time, leading to overt unsustainable pathology. Surprisingly, we find that chronic p110α partial inactivation in mice protects from age-related reduction in insulin sensitivity, glucose tolerance and fat accumulation, and extends the lifespan of male mice. This beneficial effect of p110α inactivation derives in part from a suppressed down-regulation of insulin receptor substrate (IRS) protein levels induced by age-related hyperinsulinemia, and correlates with enhanced insulin-induced Akt signalling in aged p110α-deficient mice. This temporal metabolic plasticity upon p110α inactivation indicates that prolonged PI3K inhibition, as intended in human cancer treatment, might not negatively impact on organismal metabolism.
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Affiliation(s)
- Lazaros C Foukas
- Institute of Healthy Ageing and Department of Genetics, Evolution and Environment, University College LondonDarwin Building, Gower Street, London, UK
| | - Benoit Bilanges
- Centre for Cell Signalling, Barts Cancer Institute, Queen Mary University of LondonCharterhouse Square, London, UK
| | - Lucia Bettedi
- Institute of Healthy Ageing and Department of Genetics, Evolution and Environment, University College LondonDarwin Building, Gower Street, London, UK
| | - Wayne Pearce
- Centre for Cell Signalling, Barts Cancer Institute, Queen Mary University of LondonCharterhouse Square, London, UK
| | - Khaled Ali
- Centre for Cell Signalling, Barts Cancer Institute, Queen Mary University of LondonCharterhouse Square, London, UK
| | - Sara Sancho
- Promed Laboratoire MédicalMarly, Switzerland
| | - Dominic J Withers
- Metabolic Signalling Group, Medical Research Council Clinical Sciences Centre, Imperial CollegeDu Cane Road, London, UK
| | - Bart Vanhaesebroeck
- Centre for Cell Signalling, Barts Cancer Institute, Queen Mary University of LondonCharterhouse Square, London, UK
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12
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Bilanges B, Argonza-Barrett R, Kolesnichenko M, Skinner C, Nair M, Chen M, Stokoe D. Tuberous sclerosis complex proteins 1 and 2 control serum-dependent translation in a TOP-dependent and -independent manner. Mol Cell Biol 2007; 27:5746-64. [PMID: 17562867 PMCID: PMC1952130 DOI: 10.1128/mcb.02136-06] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The tuberous sclerosis complex (TSC) proteins TSC1 and TSC2 regulate protein translation by inhibiting the serine/threonine kinase mTORC1 (for mammalian target of rapamycin complex 1). However, how TSC1 and TSC2 control overall protein synthesis and the translation of specific mRNAs in response to different mitogenic and nutritional stimuli is largely unknown. We show here that serum withdrawal inhibits mTORC1 signaling, causes disassembly of translation initiation complexes, and causes mRNA redistribution from polysomes to subpolysomes in wild-type mouse embryo fibroblasts (MEFs). In contrast, these responses are defective in Tsc1(-/-) or Tsc2(-/-) MEFs. Microarray analysis of polysome- and subpolysome-associated mRNAs uncovered specific mRNAs that are translationally regulated by serum, 90% of which are TSC1 and TSC2 dependent. Surprisingly, the mTORC1 inhibitor, rapamycin, abolished mTORC1 activity but only affected approximately 40% of the serum-regulated mRNAs. Serum-dependent signaling through mTORC1 and polysome redistribution of global and individual mRNAs were restored upon re-expression of TSC1 and TSC2. Serum-responsive mRNAs that are sensitive to inhibition by rapamycin are highly enriched for terminal oligopyrimidine and for very short 5' and 3' untranslated regions. These data demonstrate that the TSC1/TSC2 complex regulates protein translation through mainly mTORC1-dependent mechanisms and implicates a discrete profile of deregulated mRNA translation in tuberous sclerosis pathology.
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Affiliation(s)
- Benoit Bilanges
- Cancer Research Institute, University of California, San Francisco, California, USA
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13
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Abstract
Analysis of the recurrent genetic aberrations present in human tumors provides insight into how normal cells escape appropriate proliferation and survival cues. Commonly mutated genes encode proteins that monitor DNA damage (e.g., p53), proteins that regulate the cell cycle (such as Rb), and proteins that regulate signal transduction pathways (such as APC, PTEN and Ras). Analysis of the relevant targets and downstream events of these genes in normal and tumor cells will clearly highlight important pathways for tumorigenesis. However, more infrequent mutations are also informative in defining events critical for the process of tumorigenesis, and often delineate important pathways lying downstream of commonly mutated oncogenes and tumor suppressors. Together, these studies have led to the conclusion that deregulated protein synthesis plays an important role in human cancer. This review will discuss the evidence implicating mRNA translation as an important downstream consequence of signal transduction pathways initiated by mutated oncogenes and tumor suppressors, as well as additional genetic findings implicating the importance of global and specific translational control in human cancer. It will also discuss therapeutic strategies that take advantage of differences in translational regulation between normal and tumor cells.
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Affiliation(s)
- B Bilanges
- UCSF Cancer Research Institute, San Francisco, CA 94115, USA.
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14
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Abstract
PDK-1 is a protein kinase that is critical for the activation of many downstream protein kinases in the AGC superfamily, through phosphorylation of the activation loop site on these substrates. Cells lacking PDK-1 show decreased activity of these protein kinases, including protein kinase B (PKB) and p70S6K, whereas mTOR activity remains largely unaffected. Here we show, by assessing both association of cellular RNAs with polysomes and by metabolic labeling, that PDK-1-/- embryonic stem (ES) cells exhibit defects in mRNA translation. We identify which mRNAs are most dramatically translationally regulated in cells lacking PDK-1 expression by performing microarray analysis of total and polysomal RNA in these cells. In addition to the decreased translation of many RNAs, a smaller number of RNAs show increased association with polyribosomes in PDK-1-/- ES cells relative to PDK-1+/+ ES cells. We show that PKB activity is a critical downstream component of PDK-1 in mediating translation of cystatin C, RANKL, and Rab11a, whereas mTOR activity is less important for effective translation of these targets.
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Affiliation(s)
- Yuichi Tominaga
- Cancer Research Institute, University of California, San Francisco, San Francisco, California 94115
| | - Tanja Tamgüney
- Cancer Research Institute, University of California, San Francisco, San Francisco, California 94115
| | - Marina Kolesnichenko
- Cancer Research Institute, University of California, San Francisco, San Francisco, California 94115
| | - Benoit Bilanges
- Cancer Research Institute, University of California, San Francisco, San Francisco, California 94115
| | - David Stokoe
- Corresponding author. Mailing address: Cancer Research Institute, University of California, 2340 Sutter St. N319, San Francisco, CA 94115. Phone: (415) 502-2958. Fax: (415) 502-3179. E-mail:
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15
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Abstract
RNAi (RNA interference) and ASO (antisense oligonucleotide) technologies are the most commonly used approaches for silencing gene expression. However, the specificity of such powerful tools is an important factor to correctly interpret the biological consequences of gene silencing. In the present study, we examined the effects of acute loss of Ser/Thr kinase PDK1 (3-phosphoinositide-dependent kinase 1) expression using ASO and RNAi, and compared, for the first time, these two techniques using Affymetrix microarrays. We show that both ASO- and siRNA (small interfering RNA)-mediated knock-down of PDK1 expression strongly inhibited cell proliferation, although by different mechanisms, thereby questioning the specificity of these reagents. Using microarray analysis, we characterized the specificity of the ASO- and siRNA-mediated gene silencing of PDK1 by examining expression profiles 48 and 72 h following oligonucleotide transfection. At 48 h, a PDK1-dependent pattern of gene alterations was detectable, despite a large number of non-specific changes due to transfection of control nucleic acids. These non-specific alterations became more apparent at the 72 h time point, and obscured any PDK1-specific pattern. This study underscores the importance of defining appropriate control ASOs and siRNAs, using multiple oligonucleotides for each target and preferably short time points following transfection to avoid misinterpretation of the phenotype observed.
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Affiliation(s)
- Benoit Bilanges
- Cancer Research Institute, University of California, San Francisco, CA 94115, U.S.A
| | - David Stokoe
- Cancer Research Institute, University of California, San Francisco, CA 94115, U.S.A
- To whom correspondence should be addressed (email )
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16
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Brandts CH, Bilanges B, Hare G, McCormick F, Stokoe D. Phosphorylation-independent stabilization of p27kip1 by the phosphoinositide 3-kinase pathway in glioblastoma cells. J Biol Chem 2004; 280:2012-9. [PMID: 15542603 DOI: 10.1074/jbc.m408348200] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The PTEN tumor suppressor gene is a frequent target of somatic mutation, particularly in glioblastoma multiform and prostate cancer. The expression of PTEN in PTEN-mutant glioblastoma cells leads to a cell cycle arrest in G(0)/G(1) that is mediated at least partially by increased p27(kip1) levels. Here we show that p27(kip1) is not regulated by transcriptional control but that p27(kip1) protein shows increased stability after inhibition of the phosphoinositide (PI) 3-kinase pathway. Because p27(kip1) protein stability is known to be regulated by phosphorylation, we have examined modifications in the phosphorylation pattern after PI 3-kinase inhibition. Biochemical evidence suggests that p27(kip1) is phosphorylated on several serine residues, including Ser-10 and Ser-178, but that phosphorylation is unaltered by PI 3-kinase activity. This is further confirmed by the inducible expression of p27(kip1) phosphorylation site mutants, suggesting that p27(kip1) is destabilized in a phosphorylation-independent manner by the PI 3-kinase pathway at the G(1)/S transition.
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Affiliation(s)
- Christian H Brandts
- Cancer Research Institute, University of California, San Francisco, California 94115-0128, USA
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17
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Varrault A, Bilanges B, Mackay DJ, Basyuk E, Ahr B, Fernandez C, Robinson DO, Bockaert J, Journot L. Characterization of the methylation-sensitive promoter of the imprinted ZAC gene supports its role in transient neonatal diabetes mellitus. J Biol Chem 2001; 276:18653-6. [PMID: 11297535 DOI: 10.1074/jbc.c100095200] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
ZAC is a recently isolated zinc finger protein that induces apoptosis and cell cycle arrest. The corresponding gene is imprinted maternally through an unknown mechanism and maps to 6q24-q25, within the minimal interval harboring the gene responsible for transient neonatal diabetes mellitus (TNDM) and a tumor suppressor gene involved in breast cancer. Because of its functional properties, imprinting status, and expression pattern in mammary cell lines and tumors, ZAC is the best candidate so far for both disease conditions. In the present work, we delineated ZAC genomic organization and mapped its transcriptional start site. It is noteworthy that the ZAC promoter localized to the CpG island harboring the methylation imprint associated with TNDM and methylation of this promoter silenced its activity. These data indicate that the methylation mark may have a direct effect on the silencing of the ZAC imprinted allele. Our findings further strengthen the hypothesis that ZAC is the gene responsible for TNDM and suggest a novel mechanism for ZAC inactivation in breast tumors.
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Affiliation(s)
- A Varrault
- UPR 9023 CNRS-Centre CNRS-INSERM de Pharmacologie-Endocrinologie-141, rue de la Cardonille, 34094 Montpellier Cedex 05, France.
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18
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Bilanges B, Varrault A, Mazumdar A, Pantaloni C, Hoffmann A, Bockaert J, Spengler D, Journot L. Alternative splicing of the imprinted candidate tumor suppressor gene ZAC regulates its antiproliferative and DNA binding activities. Oncogene 2001; 20:1246-53. [PMID: 11313869 DOI: 10.1038/sj.onc.1204237] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2000] [Revised: 11/17/2000] [Accepted: 01/05/2001] [Indexed: 11/09/2022]
Abstract
ZAC encodes a zinc finger protein with antiproliferative activity, is maternally imprinted and is a candidate for the tumor suppressor gene on 6q24. ZAC expression is frequently lost in breast and ovary tumor-derived cell lines and down-regulated in breast primary tumors. In this report, we describe ZACDelta2, an alternatively spliced variant of ZAC lacking the sequence encoding the two N-terminal zinc fingers. Messenger RNAs encoding ZAC or ZACDelta2 were equally abundant and both proteins were nuclear. ZACDelta2 displayed an improved transactivation activity and an enhanced affinity for a ZAC binding site, suggesting that the two N-terminal zinc fingers negatively regulated ZAC binding to its target DNA sequences. Both proteins were equally efficient in preventing colony formation, indicating similar overall antiproliferative activities. However, these activities resulted from a differential regulation of apoptosis vs cell cycle progression since ZACDelta2 was more efficient at induction of cell cycle arrest than ZAC, whereas it was the reverse for apoptosis induction. Hence, these data further underline that ZAC gene is critically controlled, both at the transcriptional level through imprinting and at the functional level through alternative splicing.
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Affiliation(s)
- B Bilanges
- Mécanismes Moléculaires des Communications Cellulaires, UPR 9023 CNRS, 141 rue de la Cardonille, F-34094 Montpellier Cedex 05, France
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19
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Bilanges B, Varrault A, Basyuk E, Rodriguez C, Mazumdar A, Pantaloni C, Bockaert J, Theillet C, Spengler D, Journot L. Loss of expression of the candidate tumor suppressor gene ZAC in breast cancer cell lines and primary tumors. Oncogene 1999; 18:3979-88. [PMID: 10435621 DOI: 10.1038/sj.onc.1202933] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Loss of chromosome 6q21-qter is the second most frequent loss of chromosomal material in sporadic breast neoplasms suggesting the presence of at least one tumor suppressor gene on 6q. We recently isolated a cDNA encoding a new zinc finger protein which we named ZAC according to its functional properties, namely induction of apoptosis and control of cell cycle progression. ZAC is expressed in normal mammary gland and maps to 6q24-q25, a recognized breast cancer hot spot on 6q. In the present report, we investigated the possible inactivation of ZAC in breast cancer cell lines and primary tumors. We detected no mutation in ZAC coding region in a panel of 45 breast tumors with allelic imbalance of 6q24-q25. However, a survey of eight breast cancer cell lines showed a deeply reduced (three cell lines) or complete loss of (five cell lines) ZAC expression. Treatment of three of these cell lines with the methylation-interfering agent 5-azacytidine induced ZAC re-expression. In addition, Northern blot and RNase protection assay analysis of ZAC expression in 23 unselected primary breast tumors showed a reduced expression in several samples. Together with its functional properties and chromosomal localization, these findings substantiate ZAC as a good candidate for the tumor suppressor gene on 6q24-q25.
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Affiliation(s)
- B Bilanges
- UPR 9023 CNRS, Mécanismes Moléculaires des Communications Cellulaires, CCIPE, Montpellier, France
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20
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Varrault A, Ciani E, Apiou F, Bilanges B, Hoffmann A, Pantaloni C, Bockaert J, Spengler D, Journot L. hZAC encodes a zinc finger protein with antiproliferative properties and maps to a chromosomal region frequently lost in cancer. Proc Natl Acad Sci U S A 1998; 95:8835-40. [PMID: 9671765 PMCID: PMC21163 DOI: 10.1073/pnas.95.15.8835] [Citation(s) in RCA: 126] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
We previously reported the identification of mZac, a novel mouse zinc finger protein that shared with p53 the ability to regulate concomitantly apoptosis and cell cycle progression. We describe here the isolation, chromosomal localization, and functional in vitro characterization of its human homolog. hZAC is a widely expressed zinc finger protein that reveals transactivation and DNA-binding activity. hZAC inhibits tumor cell growth through induction of apoptotic cell death and G1 arrest. Thus hZAC, like its mouse counterpart, displays antiproliferative properties through pathways known to be central to the activity of p53. We mapped hZAC on chromosome 6q24-q25, a region frequently deleted in many solid tumors. Indeed, allelic loss at 6q24-q25 has been shown in breast and ovary cancers, melanomas, astrocytomas, and renal cell carcinomas. Furthermore, Abdollahi et al. [Abdollahi, A., Godwin, A. K., Miller, P. D., Getts, L. A., Schultz, D. C., Tagushi, T., Testa, J. R. & Hamilton, T. C. (1997) Cancer Res. 57, 2029-2034] recently isolated ZAC through its loss of expression in a surface epithelial ovary tumor model and accordingly named it Lot for "lost on transformation." In view of these observations, the functional properties we report here provide further arguments to consider hZAC as a tumor suppressor gene candidate.
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Affiliation(s)
- A Varrault
- Centre National de la Recherche Scientifique, UPR 9023, 141 rue de la Cardonille, F-34094 Montpellier Cedex 5, France.
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21
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Pantaloni C, Brabet P, Bilanges B, Dumuis A, Houssami S, Spengler D, Bockaert J, Journot L. Alternative splicing in the N-terminal extracellular domain of the pituitary adenylate cyclase-activating polypeptide (PACAP) receptor modulates receptor selectivity and relative potencies of PACAP-27 and PACAP-38 in phospholipase C activation. J Biol Chem 1996; 271:22146-51. [PMID: 8703026 DOI: 10.1074/jbc.271.36.22146] [Citation(s) in RCA: 176] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP)-27 and PACAP-38 are neuropeptides of the vasoactive intestinal peptide/secretin/glucagon family. We previously described alternative splicing of the region encoding the third intracellular loop of the PACAP receptor generating six isoforms with differential signal transduction properties (Spengler, D., Waeber, C., Pantaloni, C., Holsboer, F., Bockaert, J., Seeburg, P. H., and Journot, L. (1993) Nature 365, 170-175). In addition, we demonstrated that the potencies of the two forms of PACAP are similar for adenylate cyclase stimulation, whereas PACAP-38 is more potent than PACAP-27 in phospholipase C activation. In the present work, we document the existence of a new splice variant of the PACAP receptor that was characterized by a 21-amino-acid deletion in the N-terminal extracellular domain. We demonstrate that this domain modulates receptor selectivity with respect to PACAP-27 and -38 binding and controls the relative potencies of the two agonists in phospholipase C stimulation.
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Affiliation(s)
- C Pantaloni
- CNRS-UPR 9023, Centre CNRS-INSERM de Pharmacologie-Endocrinologie, rue de la Cardonille, F-34094 Montpellier Cedex 05, France
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