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Voigt B, Frazier K, Yazdi D, Gontarz P, Zhang B, Sepich DS, Solnica-Krezel L, Gray RS. A conserved regulation of cell expansion underlies notochord mechanics, spine morphogenesis, and endochondral bone lengthening. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.12.607640. [PMID: 39211248 PMCID: PMC11361061 DOI: 10.1101/2024.08.12.607640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Cell size is a key contributor to tissue morphogenesis 1 . As a notable example, growth plate hypertrophic chondrocytes use cellular biogenesis and disproportionate fluid uptake to expand 10-20 times in size to drive lengthening of endochondral bone 2,3 . Similarly, notochordal cells expand to one of the largest cell types in the developing embryo to drive axial extension 4-6 . In zebrafish, the notochord vacuolated cells undergo vacuole fusion to form a single large, fluid-filled vacuole that fills the cytoplasmic space and contributes to vacuolated cell expansion 7 . When this process goes awry, the notochord lacks sufficient hydrostatic pressure to support vertebral bone deposition resulting in adult spines with misshapen vertebral bones and scoliosis 8 . However, it remains unclear whether endochondral bone and the notochord share common genetic and cellular mechanisms for regulating cell and tissue expansion. Here, we demonstrate that the 5'-inositol phosphatase gene, inppl1a , regulates notochord expansion, spine morphogenesis, and endochondral bone lengthening in zebrafish. Furthermore, we show that inppl1a regulates notochord expansion independent of vacuole fusion, thereby genetically decoupling these processes. We demonstrate that inppl1a -dependent notochord expansion is essential to establish normal mechanical properties of the notochord to facilitate the development of a straight spine. Finally, we find that inppl1a is also important for endochondral bone lengthening in fish, as has been shown in the human INPPL1 -related endochondral bone disorder, Opsismodysplasia 9 . Overall, this work reveals a conserved mechanism of cell size regulation that influences disparate tissues critical for skeletal development and short-stature disorders.
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2
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Stadler KA, Ortiz-Joya LJ, Singh Sahrawat A, Buhlheller C, Gruber K, Pavkov-Keller T, O'Hagan TB, Guarné A, Pulido S, Marín-Villa M, Zangger K, Gubensäk N. Structural investigation of Trypanosoma cruzi Akt-like kinase as drug target against Chagas disease. Sci Rep 2024; 14:10039. [PMID: 38693166 PMCID: PMC11063076 DOI: 10.1038/s41598-024-59654-8] [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: 01/19/2024] [Accepted: 04/12/2024] [Indexed: 05/03/2024] Open
Abstract
According to the World Health Organization, Chagas disease (CD) is the most prevalent poverty-promoting neglected tropical disease. Alarmingly, climate change is accelerating the geographical spreading of CD causative parasite, Trypanosoma cruzi, which additionally increases infection rates. Still, CD treatment remains challenging due to a lack of safe and efficient drugs. In this work, we analyze the viability of T. cruzi Akt-like kinase (TcAkt) as drug target against CD including primary structural and functional information about a parasitic Akt protein. Nuclear Magnetic Resonance derived information in combination with Molecular Dynamics simulations offer detailed insights into structural properties of the pleckstrin homology (PH) domain of TcAkt and its binding to phosphatidylinositol phosphate ligands (PIP). Experimental data combined with Alpha Fold proposes a model for the mechanism of action of TcAkt involving a PIP-induced disruption of the intramolecular interface between the kinase and the PH domain resulting in an open conformation enabling TcAkt kinase activity. Further docking experiments reveal that TcAkt is recognized by human inhibitors PIT-1 and capivasertib, and TcAkt inhibition by UBMC-4 and UBMC-6 is achieved via binding to TcAkt kinase domain. Our in-depth structural analysis of TcAkt reveals potential sites for drug development against CD, located at activity essential regions.
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Affiliation(s)
- Karina A Stadler
- Institute of Chemistry/Organic and Bioorganic Chemistry, University of Graz, Graz, Austria
| | - Lesly J Ortiz-Joya
- Institute of Chemistry/Organic and Bioorganic Chemistry, University of Graz, Graz, Austria
- Programa de Estudio y Control de Enfermedades Tropicales (PECET), Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
- Department of Biochemistry, McGill University, Montreal, Canada
| | - Amit Singh Sahrawat
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- Innophore GmbH, Graz, Austria
| | | | - Karl Gruber
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- Innophore GmbH, Graz, Austria
- Field of Excellence BioHealth, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Tea Pavkov-Keller
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- Field of Excellence BioHealth, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | | | - Alba Guarné
- Department of Biochemistry, McGill University, Montreal, Canada
| | - Sergio Pulido
- Programa de Estudio y Control de Enfermedades Tropicales (PECET), Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
- LifeFactors ZF SAS, Rionegro, Colombia
| | - Marcel Marín-Villa
- Programa de Estudio y Control de Enfermedades Tropicales (PECET), Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
| | - Klaus Zangger
- Institute of Chemistry/Organic and Bioorganic Chemistry, University of Graz, Graz, Austria.
- Field of Excellence BioHealth, University of Graz, Graz, Austria.
- BioTechMed-Graz, Graz, Austria.
| | - Nina Gubensäk
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.
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3
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Rodgers SJ, Mitchell CA, Ooms LM. The mechanisms of class 1A PI3K and Wnt/β-catenin coupled signaling in breast cancer. Biochem Soc Trans 2023; 51:1459-1472. [PMID: 37471270 PMCID: PMC10586779 DOI: 10.1042/bst20220866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 06/08/2023] [Accepted: 07/05/2023] [Indexed: 07/22/2023]
Abstract
The class IA PI3K signaling pathway is activated by growth factor stimulation and regulates a signaling cascade that promotes diverse events including cell growth, proliferation, migration and metabolism. PI3K signaling is one of the most commonly hyperactivated pathways in breast cancer, leading to increased tumor growth and progression. PI3K hyperactivation occurs via a number of genetic and epigenetic mechanisms including mutation or amplification of PIK3CA, the gene encoding the p110α subunit of PI3Kα, as well as via dysregulation of the upstream growth factor receptors or downstream signaling effectors. Over the past decade, extensive efforts to develop therapeutics that suppress oncogenic PI3K signaling have been undertaken. Although FDA-approved PI3K inhibitors are now emerging, their clinical success remains limited due to adverse effects and negative feedback mechanisms which contribute to their reduced efficacy. There is an emerging body of evidence demonstrating crosstalk between the PI3K and Wnt/β-catenin pathways in breast cancer. However, PI3K exhibits opposing effects on Wnt/β-catenin signaling in distinct tumor subsets, whereby PI3K promotes Wnt/β-catenin activation in ER+ cancers, but paradoxically suppresses this pathway in ER- breast cancers. This review discusses the molecular mechanisms for PI3K-Wnt crosstalk in breast cancer, and how Wnt-targeted therapies have the potential to contribute to treatment regimens for breast cancers with PI3K dysregulation.
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Affiliation(s)
- Samuel J. Rodgers
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Christina A. Mitchell
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Lisa M. Ooms
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
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4
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Caligaris M, Sampaio-Marques B, Hatakeyama R, Pillet B, Ludovico P, De Virgilio C, Winderickx J, Nicastro R. The Yeast Protein Kinase Sch9 Functions as a Central Nutrient-Responsive Hub That Calibrates Metabolic and Stress-Related Responses. J Fungi (Basel) 2023; 9:787. [PMID: 37623558 PMCID: PMC10455444 DOI: 10.3390/jof9080787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 07/20/2023] [Accepted: 07/24/2023] [Indexed: 08/26/2023] Open
Abstract
Yeast cells are equipped with different nutrient signaling pathways that enable them to sense the availability of various nutrients and adjust metabolism and growth accordingly. These pathways are part of an intricate network since most of them are cross-regulated and subject to feedback regulation at different levels. In yeast, a central role is played by Sch9, a protein kinase that functions as a proximal effector of the conserved growth-regulatory TORC1 complex to mediate information on the availability of free amino acids. However, recent studies established that Sch9 is more than a TORC1-effector as its activity is tuned by several other kinases. This allows Sch9 to function as an integrator that aligns different input signals to achieve accuracy in metabolic responses and stress-related molecular adaptations. In this review, we highlight the latest findings on the structure and regulation of Sch9, as well as its role as a nutrient-responsive hub that impacts on growth and longevity of yeast cells. Given that most key players impinging on Sch9 are well-conserved, we also discuss how studies on Sch9 can be instrumental to further elucidate mechanisms underpinning healthy aging in mammalians.
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Affiliation(s)
- Marco Caligaris
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland; (M.C.); (B.P.); (C.D.V.)
| | - Belém Sampaio-Marques
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal; (B.S.-M.); (P.L.)
- ICVS/3B’s-PT Government Associate Laboratory, 4806-909 Guimarães, Portugal
| | - Riko Hatakeyama
- Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK;
| | - Benjamin Pillet
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland; (M.C.); (B.P.); (C.D.V.)
| | - Paula Ludovico
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal; (B.S.-M.); (P.L.)
- ICVS/3B’s-PT Government Associate Laboratory, 4806-909 Guimarães, Portugal
| | - Claudio De Virgilio
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland; (M.C.); (B.P.); (C.D.V.)
| | - Joris Winderickx
- Department of Biology, Functional Biology, KU Leuven, B-3001 Heverlee, Belgium;
| | - Raffaele Nicastro
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland; (M.C.); (B.P.); (C.D.V.)
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5
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Paccosi E, Balzerano A, Proietti-De-Santis L. Interfering with the Ubiquitin-Mediated Regulation of Akt as a Strategy for Cancer Treatment. Int J Mol Sci 2023; 24:ijms24032809. [PMID: 36769122 PMCID: PMC9917864 DOI: 10.3390/ijms24032809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/26/2023] [Accepted: 01/30/2023] [Indexed: 02/05/2023] Open
Abstract
The serine/threonine kinase Akt modulates the functions of numerous substrates, many of them being involved in cell proliferation and growth, metabolism, angiogenesis, resistance to hypoxia and migration. Akt is frequently deregulated in many types of human cancers, its overexpression or abnormal activation being associated with the increased proliferation and survival of cancer cells. A promising avenue for turning off the functionality of Akt is to either interfere with the K63-linked ubiquitination that is necessary for Akt membrane recruitment and activation or increase the K48-linked polyubiquitination that aims to target Akt to the proteasome for its degradation. Recent evidence indicates that targeting the ubiquitin proteasome system is effective for certain cancer treatments. In this review, the functions and roles of Akt in human cancer will be discussed, with a main focus on molecules and compounds that target various elements of the ubiquitination processes that regulate the activation and inactivation of Akt. Moreover, their possible and attractive implications for cancer therapy will be discussed.
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6
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Rodgers SJ, Jones EI, Arumugam S, Hamila SA, Danne J, Gurung R, Eramo MJ, Nanayakkara R, Ramm G, McGrath MJ, Mitchell CA. Endosome maturation links PI3Kα signaling to lysosome repopulation during basal autophagy. EMBO J 2022; 41:e110398. [PMID: 35968799 PMCID: PMC9531306 DOI: 10.15252/embj.2021110398] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 07/19/2022] [Accepted: 07/21/2022] [Indexed: 12/24/2022] Open
Abstract
Autophagy depends on the repopulation of lysosomes to degrade intracellular components and recycle nutrients. How cells co‐ordinate lysosome repopulation during basal autophagy, which occurs constitutively under nutrient‐rich conditions, is unknown. Here, we identify an endosome‐dependent phosphoinositide pathway that links PI3Kα signaling to lysosome repopulation during basal autophagy. We show that PI3Kα‐derived PI(3)P generated by INPP4B on late endosomes was required for basal but not starvation‐induced autophagic degradation. PI(3)P signals were maintained as late endosomes matured into endolysosomes, and served as the substrate for the 5‐kinase, PIKfyve, to generate PI(3,5)P2. The SNX‐BAR protein, SNX2, was recruited to endolysosomes by PI(3,5)P2 and promoted lysosome reformation. Inhibition of INPP4B/PIKfyve‐dependent lysosome reformation reduced autophagic clearance of protein aggregates during proteotoxic stress leading to increased cytotoxicity. Therefore under nutrient‐rich conditions, PI3Kα, INPP4B, and PIKfyve sequentially contribute to basal autophagic degradation and protection from proteotoxic stress via PI(3,5)P2‐dependent lysosome reformation from endolysosomes. These findings reveal that endosome maturation couples PI3Kα signaling to lysosome reformation during basal autophagy.
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Affiliation(s)
- Samuel J Rodgers
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Emily I Jones
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Senthil Arumugam
- Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.,European Molecular Biological Laboratory Australia, Monash University, Clayton, VIC, Australia
| | - Sabryn A Hamila
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Jill Danne
- Monash Ramaciotti Centre for Cryo Electron Microscopy, A Node of Microscopy Australia, Monash University, Clayton, VIC, Australia
| | - Rajendra Gurung
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Matthew J Eramo
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Randini Nanayakkara
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.,Monash Ramaciotti Centre for Cryo Electron Microscopy, A Node of Microscopy Australia, Monash University, Clayton, VIC, Australia
| | - Georg Ramm
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.,Monash Ramaciotti Centre for Cryo Electron Microscopy, A Node of Microscopy Australia, Monash University, Clayton, VIC, Australia
| | - Meagan J McGrath
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Christina A Mitchell
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
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7
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Shen Y, Jing D, Zhao Z. The effect of AKT in extracellular matrix stiffness induced osteogenic differentiation of hBMSCs. Cell Signal 2022; 99:110404. [PMID: 35835331 DOI: 10.1016/j.cellsig.2022.110404] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Revised: 07/02/2022] [Accepted: 07/08/2022] [Indexed: 02/05/2023]
Abstract
Extracellular matrix (ECM) stiffness is an important biophysical factor in human bone marrow mesenchymal stem cells (hBMSCs) differentiation. Although there is evidence that Yes-associated protein (YAP) plays an important role in ECM elasticity induced osteogenesis, but the regulatory mechanism and signaling pathways have not been distinctly uncovered. In this study, hBMSCs were cultured on collagen-coated polydimethylsiloxane hydrogels with stiffness corresponding to Young's moduli of 0.5 kPa and 32 kPa, and gene chip analyses revealed the phosphoinositide 3-kinase (PI3K)-AKT pathway was highly correlated with ECM stiffness. Following western blots indicated that AKT phosphorylation was evidently affected in 5th-7th days after ECM stiffness stimulation, while PI3K showed little difference. The AKT activator SC79 and inhibitor MK2206 were utilized to modulate AKT phosphorylation. SC79 and MK2206 caused alteration in the mRNA expression and protein level of alkaline phosphatase (ALP), collagen type I alpha 1 (COL1A1) and runt related transcription factor 2 (RUNX2). On 32 kPa substrates, YAP enrichment in nucleus were significantly promoted by SC79 and remarkably decreased by MK2206. Besides, the ratio of YAP/p-YAP is upregulated by SC79 on both 32 kPa and 0.5 kPa substrates. In conclusion, these findings suggest that AKT is involved in the modulation of ECM stiffness induced osteogenesis, and AKT phosphorylation also influences the subcellular localization and activation of YAP.
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Affiliation(s)
- Yu Shen
- School of Basic Medical Sciences, Chengdu University, Chengdu 610106, China
| | - Dian Jing
- Department of Orthodontics, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, College of Stomatology, Shanghai Jiao Tong University, National Center for Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology, China.
| | - Zhihe Zhao
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China.
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8
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mTOR substrate phosphorylation in growth control. Cell 2022; 185:1814-1836. [PMID: 35580586 DOI: 10.1016/j.cell.2022.04.013] [Citation(s) in RCA: 145] [Impact Index Per Article: 72.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 04/05/2022] [Accepted: 04/07/2022] [Indexed: 12/20/2022]
Abstract
The target of rapamycin (TOR), discovered 30 years ago, is a highly conserved serine/threonine protein kinase that plays a central role in regulating cell growth and metabolism. It is activated by nutrients, growth factors, and cellular energy. TOR forms two structurally and functionally distinct complexes, TORC1 and TORC2. TOR signaling activates cell growth, defined as an increase in biomass, by stimulating anabolic metabolism while inhibiting catabolic processes. With emphasis on mammalian TOR (mTOR), we comprehensively reviewed the literature and identified all reported direct substrates. In the context of recent structural information, we discuss how mTORC1 and mTORC2, despite having a common catalytic subunit, phosphorylate distinct substrates. We conclude that the two complexes recruit different substrates to phosphorylate a common, minimal motif.
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9
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Karmakar S, Klauda JB. Modeling the Membrane Binding Mechanism of a Lipid Transport Protein Osh4 to Single Membranes. Biophys J 2022; 121:1560-1575. [PMID: 35247338 PMCID: PMC9072576 DOI: 10.1016/j.bpj.2022.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 09/13/2021] [Accepted: 03/01/2022] [Indexed: 11/26/2022] Open
Abstract
All atom molecular dynamics simulations are utilized to unravel the binding mechanism of yeast oxysterol binding protein (Osh4) to model membranes with varying anionic lipid concentration using all-atom (AA) and the highly mobile membrane mimetic (HMMM) representations. For certain protein-lipid interactions, an improved force field description is used (CUFIX) to accurately describe lipid-protein electrostatic interactions. Our detailed computational studies have identified a single, β-crease orientated, membrane bound conformation of Osh4 for all anionic membranes. The penetration of the PHE-239 residue below the membrane phosphate plane is the characteristic signature of the membrane-bound state of Osh4. As the phenylalanine loop anchors itself deeply in the membrane; the other regions of the Osh4, namely, ALPS motif, ß6- ß7 loop, ß14- ß15 loop and ß16- ß17 loop, maximize their contact with the membrane. Furthermore, loose lipid packing and higher mobility of HMMM enables stronger association of ALPS motif with the membrane lipids through its hydrophobic surface and after the HMMM is converted to AA and equilibrated the binding is 2-3 times stronger compared to simulations started with the AA representation yielding the major importance of the ALPS motif to binding. Quantitative estimation of binding energy revealed that the phenylalanine loop plays a crucial role in stable membrane attachment of Osh4 and contributes significantly toward overall binding process. The CUFIX parameters provide a more balanced picture of hydrophobic and electrostatic interactions between the protein and the membrane which differs from our past work that showed salt bridges alone stabilized Osh4-membrane contact. Our study provides a comprehensive picture of the binding mechanism of Osh4 with model single membranes and thus, understanding of the initial interactions is important for elucidating the biological function of this protein to shuttle lipids between organelles.
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Affiliation(s)
| | - Jeffery B Klauda
- Department of Chemical and Biomolecular Engineering; Biophysics Graduate Program University of Maryland, College Park, MD 20742, USA.
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10
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The Landscape of PDK1 in Breast Cancer. Cancers (Basel) 2022; 14:cancers14030811. [PMID: 35159078 PMCID: PMC8834120 DOI: 10.3390/cancers14030811] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 12/31/2021] [Indexed: 02/04/2023] Open
Abstract
Given that 3-phosphoinositide-dependent kinase 1 (PDK1) plays a crucial role in the malignant biological behaviors of a wide range of cancers, we review the influence of PDK1 in breast cancer (BC). First, we describe the power of PDK1 in cellular behaviors and characterize the interaction networks of PDK1. Then, we establish the roles of PDK1 in carcinogenesis, growth and survival, metastasis, and chemoresistance in BC cells. More importantly, we sort the current preclinical or clinical trials of PDK1-targeted therapy in BC and find that, even though no selective PDK1 inhibitor is currently available for BC therapy, the combination trials of PDK1-targeted therapy and other agents have provided some benefit. Thus, there is increasing anticipation that PDK1-targeted therapy will have its space in future therapeutic approaches related to BC, and we hope the novel approaches of targeted therapy will be conducive to ameliorating the dismal prognosis of BC patients.
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11
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Salguero AL, Chen M, Balana AT, Chu N, Jiang H, Palanski BA, Bae H, Wright KM, Nathan S, Zhu H, Gabelli SB, Pratt MR, Cole PA. Multifaceted Regulation of Akt by Diverse C-Terminal Post-translational Modifications. ACS Chem Biol 2022; 17:68-76. [PMID: 34941261 DOI: 10.1021/acschembio.1c00632] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Akt is a Ser/Thr protein kinase that regulates cell growth and metabolism and is considered a therapeutic target for cancer. Regulation of Akt by membrane recruitment and post-translational modifications (PTMs) has been extensively studied. The most well-established mechanism for cellular Akt activation involves phosphorylation on its activation loop on Thr308 by PDK1 and on its C-terminal tail on Ser473 by mTORC2. In addition, dual phosphorylation on Ser477 and Thr479 has been shown to activate Akt. Other C-terminal tail PTMs have been identified, but their functional impacts have not been well-characterized. Here, we investigate the regulatory effects of phosphorylation of Tyr474 and O-GlcNAcylation of Ser473 on Akt. We use expressed protein ligation as a tool to produce semisynthetic Akt proteins containing phosphoTyr474 and O-GlcNAcSer473 to dissect the enzymatic functions of these PTMs. We find that O-GlcNAcylation at Ser473 and phosphorylation at Tyr474 can also partially increase Akt's kinase activity toward both peptide and protein substrates. Additionally, we performed kinase assays employing human protein microarrays to investigate global substrate specificity of Akt, comparing phosphorylated versus O-GlcNAcylated Ser473 forms. We observed a high similarity in the protein substrates phosphorylated by phosphoSer473 Akt and O-GlcNAcSer473 Akt. Two Akt substrates identified using microarrays, PPM1H, a protein phosphatase, and NEDD4L, an E3 ubiquitin ligase, were validated in solution-phase assays and cell transfection experiments.
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Affiliation(s)
- Antonieta L. Salguero
- Division of Genetics, Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts 02115, United States
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, United States
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, United States
| | - Maggie Chen
- Division of Genetics, Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts 02115, United States
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, United States
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Aaron T. Balana
- Department of Chemistry, University of Southern California, Los Angeles, California 90089 United States
| | - Nam Chu
- Department of Cancer Biology and Genetics, and the Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio 43210, United States
| | - Hanjie Jiang
- Division of Genetics, Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts 02115, United States
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, United States
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, United States
| | - Brad A. Palanski
- Division of Genetics, Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts 02115, United States
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Hwan Bae
- Division of Genetics, Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts 02115, United States
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Katharine M. Wright
- Department of Biophysics and Biophysical Chemistry, The Johns Hopkins School of Medicine, Baltimore, Maryland 21205, United States
| | - Sara Nathan
- Department of Biophysics and Biophysical Chemistry, The Johns Hopkins School of Medicine, Baltimore, Maryland 21205, United States
| | - Heng Zhu
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, United States
- The Center for High-Throughput Biology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Sandra B. Gabelli
- Department of Biophysics and Biophysical Chemistry, The Johns Hopkins School of Medicine, Baltimore, Maryland 21205, United States
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
- Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, United States
| | - Matthew R. Pratt
- Departments of Chemistry and Biological Sciences, University of Southern California, Los Angeles, California 90089 United States
| | - Philip A. Cole
- Division of Genetics, Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts 02115, United States
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, United States
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, United States
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12
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Dent P. Cell Signaling and Translational Developmental Therapeutics. COMPREHENSIVE PHARMACOLOGY 2022. [PMCID: PMC7538147 DOI: 10.1016/b978-0-12-820472-6.00002-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
The relationships between drug pharmacodynamics and subsequent changes in cellular signaling processes are complex. Many in vitro cell signaling studies often use drug concentrations above physiologically safe drug levels achievable in a patient's plasma. Drug companies develop agents to inhibit or modify the activities of specific target enzymes, often without a full consideration that their compounds have additional unknown targets. These two negative sequelae, when published together, become impediments against successful developmental therapeutics and translation because this data distorts our understanding of signaling mechanisms and reduces the probability of successfully translating drug-based concepts from the bench to the bedside. This article will discuss cellular signaling in isolation and as it relates to extant single and combined therapeutic drug interventions. This will lead to a hypothetical series standardized sequential approaches describing a rigorous concept to drug development and clinical translation.
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Class I PI3K Biology. Curr Top Microbiol Immunol 2022; 436:3-49. [DOI: 10.1007/978-3-031-06566-8_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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14
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Rajpurohit T, Bhattacharya S. Moving Towards Dawn: KRas Signaling and Treatment in Pancreatic Ductal Adenocarcinoma. Curr Mol Pharmacol 2022; 15:904-928. [PMID: 35088684 DOI: 10.2174/1874467215666220128161647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 10/20/2021] [Accepted: 11/17/2021] [Indexed: 12/24/2022]
Abstract
"Pancreatic ductal adenocarcinoma (PDAC)" is robust, nearly clueless, and all-around deadly among all tumors. Below 10 %, the general 5-year endurance period has remained adamantly unaltered in the last 30 years, regardless of enormous clinical and therapeutic endeavors. The yearly number of deaths is more than the number of recently analyzed cases. Not a classic one, but "Carbohydrate Antigen CA19- 9" remains the prevailing tool for diagnosis. MicroRNAs and non-invasive techniques are now incorporated for the effective prognosis of PDAC than just CA19-9. Mutated "Rat sarcoma virus Ras" conformation "V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog KRas" is 95 % accountable for PDAC, and its active (GTP-bound) formation activates signaling cascade comprising "Rapidly accelerated fibrosarcoma Raf"/"Mitogen-activated protein kinase MEK"/ "Extracellular signal-regulated kinase ERK" with "Phosphoinositide 3-kinase PI3K"/ "protein kinase B Akt"/ "mammalian target of rapamycin mTOR" pathways. KRas has acquired the label of 'undruggable' since the crosstalk in the nexus of pathways compensates for Raf and PI3K signaling cascade blocking. It is arduous to totally regulate KRascoordinated PDAC with traditional medicaments like "gemcitabine GEM" plus nabpaclitaxel/ FOLFIRINOX. For long-haul accomplishments aiming at KRas, future endeavors should be directed to combinatorial methodologies to adequately block KRas pathways at different standpoints. Currently they are contributing to healing PDAC. In this review article, we outline the function of KRas in carcinogenesis in PDAC, its signaling cascade, former techniques utilized in hindering Kras, current and future possibilities for targeting Kras.
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Affiliation(s)
- Tarun Rajpurohit
- Department of Pharmaceutics, School of Pharmacy & Technology Management, SVKM'S NMIMS Deemed-to-be University, Shirpur, Maharashtra 425405, India
| | - Sankha Bhattacharya
- Department of Pharmaceutics, School of Pharmacy & Technology Management, SVKM'S NMIMS Deemed-to-be University, Shirpur, Maharashtra 425405, India
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15
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Chen M, Sun T, Zhong Y, Zhou X, Zhang J. A Highly Sensitive Fluorescent Akt Biosensor Reveals Lysosome-Selective Regulation of Lipid Second Messengers and Kinase Activity. ACS CENTRAL SCIENCE 2021; 7:2009-2020. [PMID: 34963894 PMCID: PMC8704034 DOI: 10.1021/acscentsci.1c00919] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Indexed: 06/14/2023]
Abstract
The serine/threonine protein kinase Akt regulates a wide range of cellular functions via phosphorylation of various substrates distributed throughout the cell, including at the plasma membrane and endomembrane compartments. Disruption of compartmentalized Akt signaling underlies the pathology of many diseases such as cancer and diabetes. However, the specific spatial organization of Akt activity and the underlying regulatory mechanisms, particularly the mechanism controlling its activity at the lysosome, are not clearly understood. We developed a highly sensitive excitation-ratiometric Akt activity reporter (ExRai-AktAR2), enabling the capture of minute changes in Akt activity dynamics at subcellular compartments. In conjunction with super-resolution expansion microscopy, we found that growth factor stimulation leads to increased colocalization of Akt with lysosomes and accumulation of lysosomal Akt activity. We further showed that 3-phosphoinositides (3-PIs) accumulate on the lysosomal surface, in a manner dependent on dynamin-mediated endocytosis. Importantly, lysosomal 3-PIs are needed for growth-factor-induced activities of Akt and mechanistic target of rapamycin complex 1 (mTORC1) on the lysosomal surface, as targeted depletion of 3-PIs has detrimental effects. Thus, 3-PIs, a class of critical lipid second messengers that are typically found in the plasma membrane, unexpectedly accumulate on the lysosomal membrane in response to growth factor stimulation, to direct the multifaceted kinase Akt to organize lysosome-specific signaling.
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Affiliation(s)
- Mingyuan Chen
- Department
of Bioengineering, University of California,
San Diego, 9500 Gilman
Drive, La Jolla, California 92093, United States
| | - Tengqian Sun
- Department
of Pharmacology, University of California,
San Diego, 9500 Gilman
Drive, La Jolla, California 92093, United States
| | - Yanghao Zhong
- Department
of Pharmacology, University of California,
San Diego, 9500 Gilman
Drive, La Jolla, California 92093, United States
- Biomedical
Sciences Graduate Program, University of
California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Xin Zhou
- Department
of Pharmacology, University of California,
San Diego, 9500 Gilman
Drive, La Jolla, California 92093, United States
| | - Jin Zhang
- Department
of Bioengineering, University of California,
San Diego, 9500 Gilman
Drive, La Jolla, California 92093, United States
- Department
of Pharmacology, University of California,
San Diego, 9500 Gilman
Drive, La Jolla, California 92093, United States
- Department
of Chemistry & Biochemistry, University
of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
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Targeting PI3K Pathway in Pancreatic Ductal Adenocarcinoma: Rationale and Progress. Cancers (Basel) 2021; 13:cancers13174434. [PMID: 34503244 PMCID: PMC8430624 DOI: 10.3390/cancers13174434] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/24/2021] [Accepted: 08/30/2021] [Indexed: 12/12/2022] Open
Abstract
Pancreatic ductal adenocarcinoma (PDAC) remains among the deadliest solid tumors that remain treatment-refractory and show a dismal prognosis. More than 90% of PDAC tumors harbor mutations in the K-Ras that exert a strong pro-tumorigenic effect by activating several downstream effector pathways, including phosphatidylinositol-3-kinase (PI3K)-Akt. The role of frequently activated PI3K/Akt pathway in promoting PDAC aggressiveness is well established. Therapeutic approaches targeting PI3K and downstream signaling components in different cellular compartments, including tumor, stromal and immune cells, have directly impacted the tumor burden in this cancer type. Our previous work has demonstrated that targeting the PI3K/Akt/mTOR pathway reduced tumor growth and improved survival in the genetic mouse model of PDAC. Here, we discuss the significance of targeting PI3K signaling and the biological impact of PI3K inhibition in modulating the tumor-stromal immune crosstalk within the microenvironment of pancreatic cancer. Furthermore, this review updates on the current challenges involving the therapeutic implications of targeting this pathway in PDAC.
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Hua H, Zhang H, Chen J, Wang J, Liu J, Jiang Y. Targeting Akt in cancer for precision therapy. J Hematol Oncol 2021; 14:128. [PMID: 34419139 PMCID: PMC8379749 DOI: 10.1186/s13045-021-01137-8] [Citation(s) in RCA: 120] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 08/03/2021] [Indexed: 02/08/2023] Open
Abstract
Biomarkers-guided precision therapeutics has revolutionized the clinical development and administration of molecular-targeted anticancer agents. Tailored precision cancer therapy exhibits better response rate compared to unselective treatment. Protein kinases have critical roles in cell signaling, metabolism, proliferation, survival and migration. Aberrant activation of protein kinases is critical for tumor growth and progression. Hence, protein kinases are key targets for molecular targeted cancer therapy. The serine/threonine kinase Akt is frequently activated in various types of cancer. Activation of Akt promotes tumor progression and drug resistance. Since the first Akt inhibitor was reported in 2000, many Akt inhibitors have been developed and evaluated in either early or late stage of clinical trials, which take advantage of liquid biopsy and genomic or molecular profiling to realize personalized cancer therapy. Two inhibitors, capivasertib and ipatasertib, are being tested in phase III clinical trials for cancer therapy. Here, we highlight recent progress of Akt signaling pathway, review the up-to-date data from clinical studies of Akt inhibitors and discuss the potential biomarkers that may help personalized treatment of cancer with Akt inhibitors. In addition, we also discuss how Akt may confer the vulnerability of cancer cells to some kinds of anticancer agents.
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Affiliation(s)
- Hui Hua
- State Key Laboratory of Biotherapy, Laboratory of Stem Cell Biology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Hongying Zhang
- State Key Laboratory of Biotherapy, Laboratory of Oncogene, Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Jingzhu Chen
- State Key Laboratory of Biotherapy, Laboratory of Oncogene, Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Jiao Wang
- School of Basic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Jieya Liu
- State Key Laboratory of Biotherapy, Laboratory of Oncogene, Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Yangfu Jiang
- State Key Laboratory of Biotherapy, Laboratory of Oncogene, Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China.
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Truebestein L, Hornegger H, Anrather D, Hartl M, Fleming KD, Stariha JTB, Pardon E, Steyaert J, Burke JE, Leonard TA. Structure of autoinhibited Akt1 reveals mechanism of PIP 3-mediated activation. Proc Natl Acad Sci U S A 2021; 118:e2101496118. [PMID: 34385319 PMCID: PMC8379990 DOI: 10.1073/pnas.2101496118] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The protein kinase Akt is one of the primary effectors of growth factor signaling in the cell. Akt responds specifically to the lipid second messengers phosphatidylinositol-3,4,5-trisphosphate [PI(3,4,5)P3] and phosphatidylinositol-3,4-bisphosphate [PI(3,4)P2] via its PH domain, leading to phosphorylation of its activation loop and the hydrophobic motif of its kinase domain, which are critical for activity. We have now determined the crystal structure of Akt1, revealing an autoinhibitory interface between the PH and kinase domains that is often mutated in cancer and overgrowth disorders. This interface persists even after stoichiometric phosphorylation, thereby restricting maximum Akt activity to PI(3,4,5)P3- or PI(3,4)P2-containing membranes. Our work helps to resolve the roles of lipids and phosphorylation in the activation of Akt and has wide implications for the spatiotemporal control of Akt and potentially lipid-activated kinase signaling in general.
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Affiliation(s)
- Linda Truebestein
- Department of Structural and Computational Biology, Max Perutz Labs, Vienna BioCenter, 1030 Vienna, Austria
- Department of Medical Biochemistry, Medical University of Vienna, 1090 Vienna, Austria
| | - Harald Hornegger
- Department of Structural and Computational Biology, Max Perutz Labs, Vienna BioCenter, 1030 Vienna, Austria
- Department of Medical Biochemistry, Medical University of Vienna, 1090 Vienna, Austria
| | - Dorothea Anrather
- Mass Spectrometry Core Facility, Max Perutz Labs, Vienna BioCenter, 1030 Vienna, Austria
| | - Markus Hartl
- Mass Spectrometry Core Facility, Max Perutz Labs, Vienna BioCenter, 1030 Vienna, Austria
| | - Kaelin D Fleming
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | - Jordan T B Stariha
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | - Els Pardon
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium
- VIB-VUB Center for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB), 1050 Brussels, Belgium
| | - Jan Steyaert
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium
- VIB-VUB Center for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB), 1050 Brussels, Belgium
| | - John E Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Thomas A Leonard
- Department of Structural and Computational Biology, Max Perutz Labs, Vienna BioCenter, 1030 Vienna, Austria;
- Department of Medical Biochemistry, Medical University of Vienna, 1090 Vienna, Austria
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Redefining the specificity of phosphoinositide-binding by human PH domain-containing proteins. Nat Commun 2021; 12:4339. [PMID: 34267198 PMCID: PMC8282632 DOI: 10.1038/s41467-021-24639-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 06/18/2021] [Indexed: 01/02/2023] Open
Abstract
Pleckstrin homology (PH) domains are presumed to bind phosphoinositides (PIPs), but specific interaction with and regulation by PIPs for most PH domain-containing proteins are unclear. Here we employ a single-molecule pulldown assay to study interactions of lipid vesicles with full-length proteins in mammalian whole cell lysates. Of 67 human PH domain-containing proteins initially examined, 36 (54%) are found to have affinity for PIPs with various specificity, the majority of which have not been reported before. Further investigation of ARHGEF3 reveals distinct structural requirements for its binding to PI(4,5)P2 and PI(3,5)P2, and functional relevance of its PI(4,5)P2 binding. We generate a recursive-learning algorithm based on the assay results to analyze the sequences of 242 human PH domains, predicting that 49% of them bind PIPs. Twenty predicted binders and 11 predicted non-binders are assayed, yielding results highly consistent with the prediction. Taken together, our findings reveal unexpected lipid-binding specificity of PH domain-containing proteins. Pleckstrin homology (PH) domains are presumed to bind phosphoinositides (PIPs) but only few specific interactions are known. Using TIRF microscopy based assays, functional studies and an experimentally validated prediction algorithm, the authors show that specific PIP binding is widespread among human PH domains.
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20
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Live Cell Imaging and Optogenetics-Based Assays for GPCR Activity. Methods Mol Biol 2021. [PMID: 34085271 DOI: 10.1007/978-1-0716-1221-7_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
GPCRs are responsible for activation of numerous downstream effectors. Live cell imaging of these effectors therefore provides a real-time readout of GPCR activity and allows for better understanding of temporal dynamics of GPCR-mediated signaling. Opsins, or optically activatable GPCRs, allow for these signaling pathways to be activated in a spatiotemporally precise and reversible manner. Here, we describe optogenetic methods for activating Gi, Gq, and Gs signaling pathways. Additionally, we present assays for detecting activation of these pathways in real time through live cell imaging of Gβγ translocation, PIP3 increase, PIP2 hydrolysis, cAMP production, and cell migration. These assays can be utilized for GPCR-targeted drug development, as well as for studies of a wide range of GPCR-mediated physiological processes.
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21
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Nelson N, Razeto A, Gilardi A, Grättinger M, Kirchmair J, Jücker M. AKT1 and PTEN show the highest affinities among phosphoinositide binding proteins for the second messengers PtdIns(3,4,5)P 3 and PtdIns(3,4)P 2. Biochem Biophys Res Commun 2021; 568:110-115. [PMID: 34214875 DOI: 10.1016/j.bbrc.2021.06.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 06/04/2021] [Accepted: 06/07/2021] [Indexed: 12/15/2022]
Abstract
The phosphoinositides phosphatidylinositol-3,4,5-trisphosphate [PtdIns(3,4,5)P3] and phosphatidylinositol-3,4-bisphosphate [PtdIns(3,4)P2] function as second messengers and have been implicated in cancerogenesis. The signalling events downstream of PtdIns(3,4,5)P3 and PtdIns(3,4)P2 are mediated through a complex network of phosphoinositide binding effector proteins and phosphatases. In this study, we compared the phosphoinositide effector proteins AKT1, TAPP1, TAPP2, VAV1 and P-REX1 and the phosphoinositide phosphatases PTEN, SHIP1 and INPP4B for their binding affinities to PtdIns(3,4,5)P3 and/or PtdIns(3,4)P2 using Surface Plasmon Resonance. Our results demonstrate that all measured proteins except P-REX1 and VAV1 showed high affinity phosphoinositide binding with KD values in the nM to sub-nM range. Within the effector proteins, AKT1 showed the highest affinity for both PtdIns(3,4,5)P3 and PtdIns(3,4)P2. Of the phosphoinositide phosphatases PTEN displayed the highest affinity towards PtdIns(3,4,5)P3 and PtdIns(3,4)P2. The SHIP1 mutant E452K detected in carcinoma patients had a 100-fold increased affinity to PtdIns(3,4)P2 but not to PtdIns(3,4,5)P3 compared to SHIP1 WT. Distinct mutations in phosphoinositide binding proteins like the patient-derived SHIP1E452K mutant may be involved in the upregulation of PI(3,4)P2 -mediated signalling in tumor cells due to phosphoinositide trapping. Our results add further information to the complex hierarchy of phosphoinositide binding proteins helping to elucidate their functional role in cellular signal transduction.
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Affiliation(s)
- Nina Nelson
- Institute of Biochemistry and Signal Transduction, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Adelia Razeto
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Schnackenburgallee 114, 22525, Hamburg, Germany
| | - Alessia Gilardi
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Schnackenburgallee 114, 22525, Hamburg, Germany
| | - Mira Grättinger
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Schnackenburgallee 114, 22525, Hamburg, Germany
| | - Johannes Kirchmair
- Department of Pharmaceutical Sciences, Division of Pharmaceutical Chemistry, Althanstraße 14, 1090, Wien, Austria
| | - Manfred Jücker
- Institute of Biochemistry and Signal Transduction, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
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22
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INPP4B promotes PI3Kα-dependent late endosome formation and Wnt/β-catenin signaling in breast cancer. Nat Commun 2021; 12:3140. [PMID: 34035258 PMCID: PMC8149851 DOI: 10.1038/s41467-021-23241-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 04/16/2021] [Indexed: 01/17/2023] Open
Abstract
INPP4B suppresses PI3K/AKT signaling by converting PI(3,4)P2 to PI(3)P and INPP4B inactivation is common in triple-negative breast cancer. Paradoxically, INPP4B is also a reported oncogene in other cancers. How these opposing INPP4B roles relate to PI3K regulation is unclear. We report PIK3CA-mutant ER+ breast cancers exhibit increased INPP4B mRNA and protein expression and INPP4B increased the proliferation and tumor growth of PIK3CA-mutant ER+ breast cancer cells, despite suppression of AKT signaling. We used integrated proteomics, transcriptomics and imaging to demonstrate INPP4B localized to late endosomes via interaction with Rab7, which increased endosomal PI3Kα-dependent PI(3,4)P2 to PI(3)P conversion, late endosome/lysosome number and cargo trafficking, resulting in enhanced GSK3β lysosomal degradation and activation of Wnt/β-catenin signaling. Mechanistically, Wnt inhibition or depletion of the PI(3)P-effector, Hrs, reduced INPP4B-mediated cell proliferation and tumor growth. Therefore, INPP4B facilitates PI3Kα crosstalk with Wnt signaling in ER+ breast cancer via PI(3,4)P2 to PI(3)P conversion on late endosomes, suggesting these tumors may be targeted with combined PI3K and Wnt/β-catenin therapies.
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Weako J, Jang H, Keskin O, Nussinov R, Gursoy A. The structural basis of Akt PH domain interaction with calmodulin. Biophys J 2021; 120:1994-2008. [PMID: 33775637 PMCID: PMC8204387 DOI: 10.1016/j.bpj.2021.03.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 03/10/2021] [Accepted: 03/18/2021] [Indexed: 11/17/2022] Open
Abstract
Akt plays a key role in the Ras/PI3K/Akt/mTOR signaling pathway. In breast cancer, Akt translocation to the plasma membrane is enabled by the interaction of its pleckstrin homology domain (PHD) with calmodulin (CaM). At the membrane, the conformational change promoted by PIP3 releases CaM and facilitates Thr308 and Ser473 phosphorylation and activation. Here, using modeling and molecular dynamics simulations, we aim to figure out how CaM interacts with Akt's PHD at the atomic level. Our simulations show that CaM-PHD interaction is thermodynamically stable and involves a β-strand rather than an α-helix, in agreement with NMR data, and that electrostatic and hydrophobic interactions are critical. The PHD interacts with CaM lobes; however, multiple modes are possible. IP4, the polar head of PIP3, weakens the CaM-PHD interaction, implicating the release mechanism at the plasma membrane. Recently, we unraveled the mechanism of PI3Kα activation at the atomistic level and the structural basis for Ras role in the activation. Here, our atomistic structural data clarify the mechanism of how CaM interacts, delivers, and releases Akt-the next node in the Ras/PI3K pathway-at the plasma membrane.
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Affiliation(s)
- Jackson Weako
- Computational Science and Engineering Program, Koç University, Istanbul, Turkey
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland
| | - Ozlem Keskin
- Department of Chemical and Biological Engineering, Koç University, Istanbul, Turkey
| | - Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland; Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Attila Gursoy
- Department of Computer Engineering, Koç University, Istanbul, Turkey.
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Endosomal mTORC2 Is Required for Phosphoinositide-Dependent AKT Activation in Platelet-Derived Growth Factor-Stimulated Glioma Cells. Cancers (Basel) 2021; 13:cancers13102405. [PMID: 34065746 PMCID: PMC8157044 DOI: 10.3390/cancers13102405] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 11/17/2022] Open
Abstract
Simple Summary The full activation of AKT, which is necessary for cell physiological changes, is achieved through the phosphorylation of Thr308 and Ser473 in human AKT. Here, we have addressed how AKT activation at early endosomes occurs during growth factor stimulation and how mTORC2 is recruited into endosomes and associated with AKT. The explanation comes from the discovery of three important events: (1) the physical association of mSIN and Rictor, critical components for mTORC2 assembly and activity, with early endosomes; (2) the control of the recruitment of mSIN to endosomes by PtdIns(3,4)P2; and (3) the PtdIns(3,4)P2-mediated endosomal AKT activation through phosphorylation at Ser473 to control a subset of AKT substrates. Abstract The serine/threonine kinase AKT is a major effector during phosphatidylinositol 3-kinase (PI3K)-driven cell signal transduction in response to extracellular stimuli. AKT activation mechanisms have been extensively studied; however, the mechanism underlying target of rapamycin complex 2 (mTORC2) phosphorylation of AKT at Ser473 in the cellular endomembrane system remains to be elucidated. Here, we demonstrate that endocytosis is required for AKT activation through phosphorylation at Ser473 via mTORC2 using platelet-derived growth factor-stimulated U87MG glioma cells. mTORC2 components are localized to early endosomes during growth factor activation, and the association of mTORC2 with early endosomes is responsible for the local activation of AKT, which is critical for specific signal transduction through glycogen synthase kinase-3 beta and forkhead box O1/O3 phosphorylation. Furthermore, endosomal phosphoinositide, represented by PtdIns(3,4)P2, provides a binding platform for mTORC2 to phosphorylate AKT Ser473 in endosomes through mammalian Sty1/Spc1-interacting protein (mSIN), a pleckstrin homology domain-containing protein, and is dispensable for AKT phosphorylation at Thr308. This PtdIns(3,4)P2-mediated endosomal AKT activation provides a means to integrate PI3K activated by diverse stimuli to mTORC2 assembly. These early endosomal events induced by endocytosis, together with the previously identified AKT activation by PtdIns(3,4,5)P3, contribute to the strengthening of the transduction of AKT signaling through phosphoinositide.
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25
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Degan SE, Gelman IH. Emerging Roles for AKT Isoform Preference in Cancer Progression Pathways. Mol Cancer Res 2021; 19:1251-1257. [PMID: 33931488 DOI: 10.1158/1541-7786.mcr-20-1066] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 04/01/2021] [Accepted: 04/27/2021] [Indexed: 12/16/2022]
Abstract
The phosphoinositol-3 kinase (PI3K)-AKT pathway is one of the most mutated in human cancers, predominantly associated with the loss of the signaling antagonist, PTEN, and to lesser extents, with gain-of-function mutations in PIK3CA (encoding PI3K-p110α) and AKT1. In addition, most oncogenic driver pathways activate PI3K/AKT signaling. Nonetheless, drugs targeting PI3K or AKT have fared poorly against solid tumors in clinical trials as monotherapies, yet some have shown efficacy when combined with inhibitors of other oncogenic drivers, such as receptor tyrosine kinases or nuclear hormone receptors. There is growing evidence that AKT isoforms, AKT1, AKT2, and AKT3, have different, often distinct roles in either promoting or suppressing specific parameters of oncogenic progression, yet few if any isoform-preferred substrates have been characterized. This review will describe recent data showing that the differential activation of AKT isoforms is mediated by complex interplays between PTEN, PI3K isoforms and upstream tyrosine kinases, and that the efficacy of PI3K/AKT inhibitors will likely depend on the successful targeting of specific AKT isoforms and their preferred pathways.
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Affiliation(s)
- Seamus E Degan
- Department of Cancer Genetics & Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, New York
| | - Irwin H Gelman
- Department of Cancer Genetics & Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, New York.
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26
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Wright SCE, Vasilevski N, Serra V, Rodon J, Eichhorn PJA. Mechanisms of Resistance to PI3K Inhibitors in Cancer: Adaptive Responses, Drug Tolerance and Cellular Plasticity. Cancers (Basel) 2021; 13:cancers13071538. [PMID: 33810522 PMCID: PMC8037590 DOI: 10.3390/cancers13071538] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 03/11/2021] [Accepted: 03/15/2021] [Indexed: 12/24/2022] Open
Abstract
The phosphatidylinositol-3-kinase (PI3K) pathway plays a central role in the regulation of several signalling cascades which regulate biological processes such as cellular growth, survival, proliferation, motility and angiogenesis. The hyperactivation of this pathway is linked to tumour progression and is one of the most common events in human cancers. Additionally, aberrant activation of the PI3K pathway has been demonstrated to limit the effectiveness of a number of anti-tumour agents paving the way for the development and implementation of PI3K inhibitors in the clinic. However, the overall effectiveness of these compounds has been greatly limited by inadequate target engagement due to reactivation of the pathway by compensatory mechanisms. Herein, we review the common adaptive responses that lead to reactivation of the PI3K pathway, therapy resistance and potential strategies to overcome these mechanisms of resistance. Furthermore, we highlight the potential role in changes in cellular plasticity and PI3K inhibitor resistance.
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Affiliation(s)
- Sarah Christine Elisabeth Wright
- Faculty of Health Sciences, Curtin Medical School, Curtin University, Bentley 6102, Australia;
- Curtin Health Innovation Research Institute and Faculty of Health Sciences, Curtin University, Bentley 6102, Australia
- Correspondence: (S.C.E.W.); (N.V.)
| | - Natali Vasilevski
- Faculty of Health Sciences, Curtin Medical School, Curtin University, Bentley 6102, Australia;
- Curtin Health Innovation Research Institute and Faculty of Health Sciences, Curtin University, Bentley 6102, Australia
- Correspondence: (S.C.E.W.); (N.V.)
| | - Violeta Serra
- Vall d’Hebron Institute of Oncology (VHIO), Vall d’Hebron University Hospital, 08035 Barcelona, Spain;
| | - Jordi Rodon
- MD Anderson Cancer Center, Investigational Cancer Therapeutics Department, Houston, TX 77030, USA;
| | - Pieter Johan Adam Eichhorn
- Faculty of Health Sciences, Curtin Medical School, Curtin University, Bentley 6102, Australia;
- Curtin Health Innovation Research Institute and Faculty of Health Sciences, Curtin University, Bentley 6102, Australia
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
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27
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Norris D, Yang P, Shin SY, Kearney AL, Kim HJ, Geddes T, Senior AM, Fazakerley DJ, Nguyen LK, James DE, Burchfield JG. Signaling Heterogeneity is Defined by Pathway Architecture and Intercellular Variability in Protein Expression. iScience 2021; 24:102118. [PMID: 33659881 PMCID: PMC7892930 DOI: 10.1016/j.isci.2021.102118] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 01/07/2021] [Accepted: 01/22/2021] [Indexed: 12/12/2022] Open
Abstract
Insulin's activation of PI3K/Akt signaling, stimulates glucose uptake by enhancing delivery of GLUT4 to the cell surface. Here we examined the origins of intercellular heterogeneity in insulin signaling. Akt activation alone accounted for ~25% of the variance in GLUT4, indicating that additional sources of variance exist. The Akt and GLUT4 responses were highly reproducible within the same cell, suggesting the variance is between cells (extrinsic) and not within cells (intrinsic). Generalized mechanistic models (supported by experimental observations) demonstrated that the correlation between the steady-state levels of two measured signaling processes decreases with increasing distance from each other and that intercellular variation in protein expression (as an example of extrinsic variance) is sufficient to account for the variance in and between Akt and GLUT4. Thus, the response of a population to insulin signaling is underpinned by considerable single-cell heterogeneity that is largely driven by variance in gene/protein expression between cells. Insulin signaling is heterogeneous between cells in the same population The temporal response of signaling components within a cell is highly reproducible Upstream responses (Akt) can only partially predict downstream response (GLUT4) Protein expression variance is a driver of intercellular signaling heterogeneity
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Affiliation(s)
- Dougall Norris
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Pengyi Yang
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Mathematics and Statistics, The University of Sydney, Sydney, NSW 2006, Australia.,Computational Systems Biology Group, Children's Medical Research Institute, Faculty of Medicine and Health, The University of Sydney, Westmead, NSW 2145, Australia
| | - Sung-Young Shin
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, VIC 3800, Australia.,Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - Alison L Kearney
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Hani Jieun Kim
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Mathematics and Statistics, The University of Sydney, Sydney, NSW 2006, Australia.,Computational Systems Biology Group, Children's Medical Research Institute, Faculty of Medicine and Health, The University of Sydney, Westmead, NSW 2145, Australia
| | - Thomas Geddes
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Mathematics and Statistics, The University of Sydney, Sydney, NSW 2006, Australia.,Computational Systems Biology Group, Children's Medical Research Institute, Faculty of Medicine and Health, The University of Sydney, Westmead, NSW 2145, Australia
| | - Alistair M Senior
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Daniel J Fazakerley
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia
| | - Lan K Nguyen
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, VIC 3800, Australia.,Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - David E James
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia.,Sydney Medical School, The University of Sydney, Sydney, NSW 2006, Australia
| | - James G Burchfield
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia.,School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
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28
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Smith SL, Pitt AR, Spickett CM. Approaches to Investigating the Protein Interactome of PTEN. J Proteome Res 2020; 20:60-77. [PMID: 33074689 DOI: 10.1021/acs.jproteome.0c00570] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The tumor suppressor phosphatase and tensin homologue (PTEN) is a redox-sensitive dual specificity phosphatase with an essential role in the negative regulation of the PI3K-AKT signaling pathway, affecting metabolic and cell survival processes. PTEN is commonly mutated in cancer, and dysregulation in the metabolism of PIP3 is implicated in other diseases such as diabetes. PTEN interactors are responsible for some functional roles of PTEN beyond the negative regulation of the PI3K pathway and are thus of great importance in cell biology. Both high-data content proteomics-based approaches and low-data content PPI approaches have been used to investigate the interactome of PTEN and elucidate further functions of PTEN. While low-data content approaches rely on co-immunoprecipitation and Western blotting, and as such require previously generated hypotheses, high-data content approaches such as affinity pull-down proteomic assays or the yeast 2-hybrid system are hypothesis generating. This review provides an overview of the PTEN interactome, including redox effects, and critically appraises the methods and results of high-data content investigations into the global interactome of PTEN. The biological significance of findings from recent studies is discussed and illustrates the breadth of cellular functions of PTEN that can be discovered by these approaches.
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Affiliation(s)
- Sarah L Smith
- School of Life and Health Sciences, Aston Triangle, Aston University, B4 7ET, Birmingham, U.K
| | - Andrew R Pitt
- School of Life and Health Sciences, Aston Triangle, Aston University, B4 7ET, Birmingham, U.K.,Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester, M1 7DN, U.K
| | - Corinne M Spickett
- School of Life and Health Sciences, Aston Triangle, Aston University, B4 7ET, Birmingham, U.K
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29
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Showalter L, Czerniecki BJ, Koski GK. Th1 cytokines in conjunction with pharmacological Akt inhibition potentiate apoptosis of breast cancer cells in vitro and suppress tumor growth in vivo. Oncotarget 2020; 11:2873-2888. [PMID: 32774769 PMCID: PMC7392628 DOI: 10.18632/oncotarget.27556] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 03/19/2020] [Indexed: 11/25/2022] Open
Abstract
Targeted drug approaches have been a major focus for developing new anticancer therapies. Although many such agents approved in the last 20 years have improved outcomes, almost all have underperformed expectations. The full potential of such agents may yet be obtained through novel combinations. Previously, we showed that anti-estrogen drugs combined with a dendritic cell-based anti-HER-2 vaccine known to induce strong Th1-polarized immunity dramatically improved clinical response rates in patients with HER-2pos/ERpos early breast cancer. Here, we show that the small molecule Akt antagonist MK-2206, when combined with the Th1 cytokines IFN-gamma and TNF-alpha, maximize indicators of apoptotic cell death in a panel of phenotypically-diverse human breast cancer lines. These findings were mirrored by other, structurally-unrelated Akt-targeting drugs that work through different mechanisms. Interestingly, we found that MK-2206, as well as the other Akt antagonist drugs, also had a tendency to suppress Th1 cytokine expression in stimulated human and murine lymphocytes, potentially complicating their use in conjunction with active immunotherapy. After verifying that MK-2206 plus IFN-gamma could show similar combined effects against breast cancer lines, even in the absence of TNF-alpha, we tested in a rodent HER-2pos breast cancer model either a HER-2-based DC vaccine, or recombinant IFN-gamma with or without MK-2206 administration. We found that for MK-2206, co-administration of recombinant IFN-gamma outperformed co-administration of DC vaccination for slowing tumor growth kinetics. These findings suggest a combined therapy approach for Akt-targeting drugs that incorporates recombinant Interferon-gamma and is potentially translatable to humans.
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Affiliation(s)
- Loral Showalter
- Department of Biological Sciences, University Esplanade, Kent State University, Kent, Ohio, USA
| | - Brian J Czerniecki
- Department of Breast Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA
| | - Gary K Koski
- Department of Biological Sciences, University Esplanade, Kent State University, Kent, Ohio, USA
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30
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Chen Y, Ohki R. p53-PHLDA3-Akt Network: The Key Regulators of Neuroendocrine Tumorigenesis. Int J Mol Sci 2020; 21:ijms21114098. [PMID: 32521808 PMCID: PMC7312810 DOI: 10.3390/ijms21114098] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/02/2020] [Accepted: 06/06/2020] [Indexed: 01/10/2023] Open
Abstract
p53 is a well-known tumor suppressor gene and one of the most extensively studied genes in cancer research. p53 functions largely as a transcription factor and can trigger a variety of antiproliferative programs via induction of its target genes. We identified PHLDA3 as a p53 target gene and found that its protein product is a suppressor of pancreatic neuroendocrine tumors (PanNETs) and a repressor of Akt function. PHLDA3 is frequently inactivated by loss of heterozygosity (LOH) and methylation in human PanNETs, and LOH at the PHLDA3 gene locus correlates with PanNET progression and poor prognosis. In addition, in PHLDA3-deficient mice, pancreatic islet cells proliferate abnormally and acquire resistance to apoptosis. In this article, we briefly review the roles of p53 and Akt in human neuroendocrine tumors (NETs) and describe the relationship between the p53-PHLDA3 and Akt pathways. We also discuss the role of PHLDA3 as a tumor suppressor in various NETs and speculate on the possibility that loss of PHLDA3 function may be a useful prognostic marker for NET patients indicating particular drug therapies. These results suggest that targeting the downstream PHLDA3-Akt pathway might provide new therapies to treat NETs.
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31
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Garrido CM, Henkels KM, Rehl KM, Liang H, Zhou Y, Gutterman JU, Cho KJ. Avicin G is a potent sphingomyelinase inhibitor and blocks oncogenic K- and H-Ras signaling. Sci Rep 2020; 10:9120. [PMID: 32499517 PMCID: PMC7272413 DOI: 10.1038/s41598-020-65882-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 05/05/2020] [Indexed: 12/23/2022] Open
Abstract
K-Ras must interact primarily with the plasma membrane (PM) for its biological activity. Therefore, disrupting K-Ras PM interaction is a tractable approach to block oncogenic K-Ras activity. Here, we found that avicin G, a family of natural plant-derived triterpenoid saponins from Acacia victoriae, mislocalizes K-Ras from the PM and disrupts PM spatial organization of oncogenic K-Ras and H-Ras by depleting phosphatidylserine (PtdSer) and cholesterol contents, respectively, at the inner PM leaflet. Avicin G also inhibits oncogenic K- and H-Ras signal output and the growth of K-Ras-addicted pancreatic and non-small cell lung cancer cells. We further identified that avicin G perturbs lysosomal activity, and disrupts cellular localization and activity of neutral and acid sphingomyelinases (SMases), resulting in elevated cellular sphingomyelin (SM) levels and altered SM distribution. Moreover, we show that neutral SMase inhibitors disrupt the PM localization of K-Ras and PtdSer and oncogenic K-Ras signaling. In sum, this study identifies avicin G as a new potent anti-Ras inhibitor, and suggests that neutral SMase can be a tractable target for developing anti-K-Ras therapeutics.
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Affiliation(s)
- Christian M Garrido
- Department of Biochemistry and Molecular Biology, School of Boonshoft Medical School, Wright State University, Dayton, OH, 45435, United States
| | - Karen M Henkels
- Department of Biochemistry and Molecular Biology, School of Boonshoft Medical School, Wright State University, Dayton, OH, 45435, United States
| | - Kristen M Rehl
- Department of Biochemistry and Molecular Biology, School of Boonshoft Medical School, Wright State University, Dayton, OH, 45435, United States
| | - Hong Liang
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, United States
| | - Yong Zhou
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, United States
| | - Jordan U Gutterman
- Department of Systems Biology, The University of Texas M. D. Anderson Cancer Center, Houston, TX, 77030, United States
| | - Kwang-Jin Cho
- Department of Biochemistry and Molecular Biology, School of Boonshoft Medical School, Wright State University, Dayton, OH, 45435, United States.
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32
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Du X, Zhang Y, Li X, Li Q, Wu C, Chen G, Guo X, Weng Y, Wang Z. PRL2 serves as a negative regulator in cell adaptation to oxidative stress. Cell Biosci 2019; 9:96. [PMID: 31798830 PMCID: PMC6884919 DOI: 10.1186/s13578-019-0358-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Accepted: 11/21/2019] [Indexed: 12/02/2022] Open
Abstract
High levels of ROS cause oxidative stress, which plays a critical role in cell death. As a ROS effector protein, PRL2 senses ROS and controls phagocyte bactericidal activity during infection. Here we report PRL2 regulates oxidative stress induced cell death. PRL2 senses oxidative stress via highly reactive cysteine residues at 46 and 101. The oxidation of PRL2 causes protein degradation and supports pro-survival PDK1/AKT signal which in turn to protect cells against oxidative stress. As a result, PRL2 levels have a high correlation with oxidative stress induced cell death. In vivo experiments showed PRL2 deficient cells survive better in inflammatory oxidative environment and resist to ionizing radiation. Our finding suggests PRL2 serves as a negative regulator in cell adaptation to oxidative stress. Therefore, PRL2 could be targeted to modulate cell viability in inflammation or irradiation associated therapy.
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Affiliation(s)
- Xinyue Du
- 1Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Rm 709 Bldg 5, 280 S. Chongqing Rd, Shanghai, 200025 People's Republic of China
| | - Yang Zhang
- 1Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Rm 709 Bldg 5, 280 S. Chongqing Rd, Shanghai, 200025 People's Republic of China
| | - Xiao Li
- 1Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Rm 709 Bldg 5, 280 S. Chongqing Rd, Shanghai, 200025 People's Republic of China
| | - Qi Li
- 1Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Rm 709 Bldg 5, 280 S. Chongqing Rd, Shanghai, 200025 People's Republic of China
| | - Chenyun Wu
- 1Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Rm 709 Bldg 5, 280 S. Chongqing Rd, Shanghai, 200025 People's Republic of China
| | - Guangjie Chen
- 1Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Rm 709 Bldg 5, 280 S. Chongqing Rd, Shanghai, 200025 People's Republic of China
| | - XiaoKui Guo
- 3Institute for Global Health, Shanghai Jiao Tong University School of Medicine-Chinese Center for Tropical Diseases Research, Shanghai, 200025 People's Republic of China
| | - Yongqiang Weng
- 2Department of General Surgery, Huadong Hospital, Shanghai Medical College, Fudan University, Shanghai, 200040 People's Republic of China
| | - Zhaojun Wang
- 1Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Rm 709 Bldg 5, 280 S. Chongqing Rd, Shanghai, 200025 People's Republic of China
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33
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Zhang Y, Zhang Q, Bao J, Huang J, Zhang H. Apiosporamide, A 4-hydroxy-2-pyridone Alkaloid, Induces Apoptosis Via PI3K/Akt Signaling Pathway In Osteosarcoma Cells. Onco Targets Ther 2019; 12:8611-8620. [PMID: 31695421 PMCID: PMC6814361 DOI: 10.2147/ott.s218692] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 09/20/2019] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Osteosarcoma (OS) is a common primary malignant bone tumour in children and young adults. Apiosporamide, a 4-hydroxy-2-pyridone alkaloid from a deep-sea-derived fungus, Arthrinium sp. UJNMF0008, showed anti-proliferative effects toward a panel of human cancer cell lines, and the molecular mechanism in MG63 cells was then investigated in the current work. METHODS Cell viability was determined with MTT method. Cell proliferation was detected using colony-formation assay. Screening electron microscope was used for morphology observation. Cell cycle and apoptosis was analysed via flow cytometry. Real-time PCR was conducted to evaluate the mRNA expression related with cell apoptosis. The expression levels of proteins related to capase-mediated apoptotic pathway and PI3K/Akt signalling pathway were detected by Western blotting. RESULTS Apiosporamide significantly decreased cell viability in cancer cells, and also exhibited excellent anti-proliferative effect. Apiosporamide caused cell cycle arrests at G0/G1 phase in MG63 cells. Moreover, apiosporamide induced apoptosis, activated caspase-3, caspase-8 and caspase-9, and regulated expression of Bax and Bcl-2 in MG63 cells. In addition, apiosporamide also attenuated PI3K/Akt signaling pathway. CONCLUSION Apiosporamide effectively suppressed MG63 cells proliferation by inducing apoptosis through PI3K/Akt and caspase-associated apoptotic pathway.
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Affiliation(s)
- Yuying Zhang
- Department of Biotechnology, School of Biological Science and Technology, University of Jinan, Jinan250022, People’s Republic of China
| | - Qianqian Zhang
- Department of Biotechnology, School of Biological Science and Technology, University of Jinan, Jinan250022, People’s Republic of China
| | - Jie Bao
- Department of Biotechnology, School of Biological Science and Technology, University of Jinan, Jinan250022, People’s Republic of China
| | - Jintian Huang
- Department of Orthopedics, Shandong Provincial Hospital Affiliated to Shandong University, Jinan250021, People’s Republic of China
| | - Hua Zhang
- Department of Biotechnology, School of Biological Science and Technology, University of Jinan, Jinan250022, People’s Republic of China
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Miller TE, Henkels KM, Huddleston M, Salisbury R, Hussain SM, Sasaki AT, Cho KJ. Depletion of phosphatidylinositol 4-phosphate at the Golgi translocates K-Ras to mitochondria. J Cell Sci 2019; 132:jcs.231886. [PMID: 31331963 DOI: 10.1242/jcs.231886] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 07/12/2019] [Indexed: 01/05/2023] Open
Abstract
Ras proteins are small GTPases localized to the plasma membrane (PM), which regulate cellular proliferation, apoptosis and differentiation. After a series of post-translational modifications, H-Ras and N-Ras traffic to the PM from the Golgi via the classical exocytic pathway, but the exact mechanism of K-Ras trafficking to the PM from the ER is not fully characterized. ATP5G1 (also known as ATP5MC1) is one of the three proteins that comprise subunit c of the F 0 complex of the mitochondrial ATP synthase. In this study, we show that overexpression of the mitochondrial targeting sequence of ATP5G1 perturbs glucose metabolism, inhibits oncogenic K-Ras signaling, and redistributes phosphatidylserine (PtdSer) to mitochondria and other endomembranes, resulting in K-Ras translocation to mitochondria. Also, it depletes phosphatidylinositol 4-phosphate (PI4P) at the Golgi. Glucose supplementation restores PtdSer and K-Ras PM localization and PI4P at the Golgi. We further show that inhibition of the Golgi-localized PI4-kinases (PI4Ks) translocates K-Ras, and PtdSer to mitochondria and endomembranes, respectively. We conclude that PI4P at the Golgi regulates the PM localization of PtdSer and K-Ras.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Taylor E Miller
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, OH 45435, USA
| | - Karen M Henkels
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, OH 45435, USA
| | - Mary Huddleston
- Human Signatures Branch, Human-Centered ISR Division, Airman Systems Directorate, 711 Human Performance Wing, Air Force Research Laboratory, Wright Patterson Air Force Base, OH 45433, USA
| | - Richard Salisbury
- Human Signatures Branch, Human-Centered ISR Division, Airman Systems Directorate, 711 Human Performance Wing, Air Force Research Laboratory, Wright Patterson Air Force Base, OH 45433, USA
| | - Saber M Hussain
- Human Signatures Branch, Human-Centered ISR Division, Airman Systems Directorate, 711 Human Performance Wing, Air Force Research Laboratory, Wright Patterson Air Force Base, OH 45433, USA
| | - Atsuo T Sasaki
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Kwang-Jin Cho
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, OH 45435, USA
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35
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Nakada-Tsukui K, Watanabe N, Maehama T, Nozaki T. Phosphatidylinositol Kinases and Phosphatases in Entamoeba histolytica. Front Cell Infect Microbiol 2019; 9:150. [PMID: 31245297 PMCID: PMC6563779 DOI: 10.3389/fcimb.2019.00150] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 04/23/2019] [Indexed: 12/11/2022] Open
Abstract
Phosphatidylinositol (PtdIns) metabolism is indispensable in eukaryotes. Phosphoinositides (PIs) are phosphorylated derivatives of PtdIns and consist of seven species generated by reversible phosphorylation of the inositol moieties at the positions 3, 4, and 5. Each of the seven PIs has a unique subcellular and membrane domain distribution. In the enteric protozoan parasite Entamoeba histolytica, it has been previously shown that the PIs phosphatidylinositol 3-phosphate (PtdIns3P), PtdIns(4,5)P2, and PtdIns(3,4,5)P3 are localized to phagosomes/phagocytic cups, plasma membrane, and phagocytic cups, respectively. The localization of these PIs in E. histolytica is similar to that in mammalian cells, suggesting that PIs have orthologous functions in E. histolytica. In contrast, the conservation of the enzymes that metabolize PIs in this organism has not been well-documented. In this review, we summarized the full repertoire of the PI kinases and PI phosphatases found in E. histolytica via a genome-wide survey of the current genomic information. E. histolytica appears to have 10 PI kinases and 23 PI phosphatases. It has a panel of evolutionarily conserved enzymes that generate all the seven PI species. However, class II PI 3-kinases, type II PI 4-kinases, type III PI 5-phosphatases, and PI 4P-specific phosphatases are not present. Additionally, regulatory subunits of class I PI 3-kinases and type III PI 4-kinases have not been identified. Instead, homologs of class I PI 3-kinases and PTEN, a PI 3-phosphatase, exist as multiple isoforms, which likely reflects that elaborate signaling cascades mediated by PtdIns(3,4,5)P3 are present in this organism. There are several enzymes that have the nuclear localization signal: one phosphatidylinositol phosphate (PIP) kinase, two PI 3-phosphatases, and one PI 5-phosphatase; this suggests that PI metabolism also has conserved roles related to nuclear functions in E. histolytica, as it does in model organisms.
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Affiliation(s)
- Kumiko Nakada-Tsukui
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Natsuki Watanabe
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan.,Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Tomohiko Maehama
- Division of Molecular and Cellular Biology, Graduate School of Medicine, Kobe University, Kobe, Japan
| | - Tomoyoshi Nozaki
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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36
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Lipid-dependent Akt-ivity: where, when, and how. Biochem Soc Trans 2019; 47:897-908. [PMID: 31147387 PMCID: PMC6599160 DOI: 10.1042/bst20190013] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 05/08/2019] [Accepted: 05/08/2019] [Indexed: 02/07/2023]
Abstract
Akt is an essential protein kinase activated downstream of phosphoinositide 3-kinase and frequently hyperactivated in cancer. Canonically, Akt is activated by phosphoinositide-dependent kinase 1 and mechanistic target of rapamycin complex 2, which phosphorylate it on two regulatory residues in its kinase domain upon targeting of Akt to the plasma membrane by PI(3,4,5)P3. Recent evidence, however, has shown that, in addition to phosphorylation, Akt activity is allosterically coupled to the engagement of PI(3,4,5)P3 or PI(3,4)P2 in cellular membranes. Furthermore, the active membrane-bound conformation of Akt is protected from dephosphorylation, and Akt inactivation by phosphatases is rate-limited by its dissociation. Thus, Akt activity is restricted to membranes containing either PI(3,4,5)P3 or PI(3,4)P2. While PI(3,4,5)P3 has long been associated with signaling at the plasma membrane, PI(3,4)P2 is gaining increasing traction as a signaling lipid and has been implicated in controlling Akt activity throughout the endomembrane system. This has clear implications for the phosphorylation of both freely diffusible substrates and those localized to discrete subcellular compartments.
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37
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Amable G, Martínez-León E, Picco ME, Di Siervi N, Davio C, Rozengurt E, Rey O. Metformin inhibits β-catenin phosphorylation on Ser-552 through an AMPK/PI3K/Akt pathway in colorectal cancer cells. Int J Biochem Cell Biol 2019; 112:88-94. [PMID: 31082618 DOI: 10.1016/j.biocel.2019.05.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 05/06/2019] [Accepted: 05/08/2019] [Indexed: 02/08/2023]
Abstract
Several epidemiologic studies have revealed strong inverse associations between metformin use and risk of colorectal cancer development. Nevertheless, the underlying mechanisms are still uncertain. The Wnt/β-catenin pathway, which plays a central role in intestinal homeostasis and sporadic colorectal cancer development, is regulated by phosphorylation cascades that are dependent and independent of Wnt. Here we report that a non-canonical Ser552 phosphorylation in β-catenin, which promotes its nuclear accumulation and transcriptional activity, is blocked by metformin via AMPK-mediated PI3K/Akt signaling inhibition.
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Affiliation(s)
- Gastón Amable
- Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Argentina; Instituto de Inmunología, Genética y Metabolismo, Facultad de Farmacia y Bioquímica, Hospital de Clínicas "José de San Martín", Caba, 1120, Argentina
| | - Eduardo Martínez-León
- Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Argentina; Instituto de Inmunología, Genética y Metabolismo, Facultad de Farmacia y Bioquímica, Hospital de Clínicas "José de San Martín", Caba, 1120, Argentina
| | - María Elisa Picco
- Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Argentina; Instituto de Inmunología, Genética y Metabolismo, Facultad de Farmacia y Bioquímica, Hospital de Clínicas "José de San Martín", Caba, 1120, Argentina
| | - Nicolas Di Siervi
- Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Argentina; Instituto de Investigaciones Farmacológicas, Facultad de Farmacia y Bioquímica, Argentina
| | - Carlos Davio
- Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Argentina; Instituto de Investigaciones Farmacológicas, Facultad de Farmacia y Bioquímica, Argentina; Departamento de Farmacología, Caba, 1113, Argentina
| | - Enrique Rozengurt
- Unit of Signal Transduction and Gastrointestinal Cancer, Division of Digestive Diseases, Department of Medicine, CURE: Digestive Diseases Research Center, Molecular Biology Institute and Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California at Los Angeles, CA, 90095-1786, USA
| | - Osvaldo Rey
- Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Argentina; Instituto de Inmunología, Genética y Metabolismo, Facultad de Farmacia y Bioquímica, Hospital de Clínicas "José de San Martín", Caba, 1120, Argentina.
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38
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Abstract
In this issue of Molecular Cell, Liu et al. (2018) show that PI34P2 and PIP3, the lipid products of class I phosphoinositide 3-kinase (PI3K), display distinct spatiotemporal kinetics in cells that result in differential activation of the effectors AKT1, AKT2, and AKT3.
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Affiliation(s)
- Alex Toker
- Department of Pathology and Cancer Center, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA.
| | - Christian C Dibble
- Department of Pathology and Cancer Center, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA.
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39
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de la Cruz López KG, Toledo Guzmán ME, Sánchez EO, García Carrancá A. mTORC1 as a Regulator of Mitochondrial Functions and a Therapeutic Target in Cancer. Front Oncol 2019; 9:1373. [PMID: 31921637 PMCID: PMC6923780 DOI: 10.3389/fonc.2019.01373] [Citation(s) in RCA: 120] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Accepted: 11/21/2019] [Indexed: 02/05/2023] Open
Abstract
Continuous proliferation of tumor cells requires constant adaptations of energy metabolism to rapidly fuel cell growth and division. This energetic adaptation often comprises deregulated glucose uptake and lactate production in the presence of oxygen, a process known as the "Warburg effect." For many years it was thought that the Warburg effect was a result of mitochondrial damage, however, unlike this proposal tumor cell mitochondria maintain their functionality, and is essential for integrating a variety of signals and adapting the metabolic activity of the tumor cell. The mammalian/mechanistic target of rapamycin complex 1 (mTORC1) is a master regulator of numerous cellular processes implicated in proliferation, metabolism, and cell growth. mTORC1 controls cellular metabolism mainly by regulating the translation and transcription of metabolic genes, such as peroxisome proliferator activated receptor γ coactivator-1 α (PGC-1α), sterol regulatory element-binding protein 1/2 (SREBP1/2), and hypoxia inducible factor-1 α (HIF-1α). Interestingly it has been shown that mTORC1 regulates mitochondrial metabolism, thus representing an important regulator in mitochondrial function. Here we present an overview on the role of mTORC1 in the regulation of mitochondrial functions in cancer, considering new evidences showing that mTORC1 regulates the translation of nucleus-encoded mitochondrial mRNAs that result in an increased ATP mitochondrial production. Moreover, we discuss the relationship between mTORC1 and glutaminolysis, as well as mitochondrial metabolites. In addition, mitochondrial fission processes regulated by mTORC1 and its impact on cancer are discussed. Finally, we also review the therapeutic efficacy of mTORC1 inhibitors in cancer treatments, considering its use in combination with other drugs, with particular focus on cellular metabolism inhibitors, that could help improve their anti neoplastic effect and eliminate cancer cells in patients.
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Affiliation(s)
- Karen Griselda de la Cruz López
- Posgrado en Ciencias Biomédicas, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | | | | | - Alejandro García Carrancá
- Unidad de Investigación Biomédica en Cáncer, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México & Instituto Nacional de Cancerología, Secretaría de Salud, Mexico City, Mexico
- *Correspondence: Alejandro García Carrancá
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40
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Stratiievska A, Nelson S, Senning EN, Lautz JD, Smith SE, Gordon SE. Reciprocal regulation among TRPV1 channels and phosphoinositide 3-kinase in response to nerve growth factor. eLife 2018; 7:38869. [PMID: 30560783 PMCID: PMC6312403 DOI: 10.7554/elife.38869] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Accepted: 12/06/2018] [Indexed: 12/12/2022] Open
Abstract
Although it has been known for over a decade that the inflammatory mediator NGF sensitizes pain-receptor neurons through increased trafficking of TRPV1 channels to the plasma membrane, the mechanism by which this occurs remains mysterious. NGF activates phosphoinositide 3-kinase (PI3K), the enzyme that generates PI(3,4)P2 and PIP3, and PI3K activity is required for sensitization. One tantalizing hint came from the finding that the N-terminal region of TRPV1 interacts directly with PI3K. Using two-color total internal reflection fluorescence microscopy, we show that TRPV1 potentiates NGF-induced PI3K activity. A soluble TRPV1 fragment corresponding to the N-terminal Ankyrin repeats domain (ARD) was sufficient to produce this potentiation, indicating that allosteric regulation was involved. Further, other TRPV channels with conserved ARDs also potentiated NGF-induced PI3K activity. Our data demonstrate a novel reciprocal regulation of PI3K signaling by the ARD of TRPV channels.
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Affiliation(s)
| | - Sara Nelson
- Department of Physiology and Biophysics, University of Washington, Seattle, United States
| | - Eric N Senning
- Department of Physiology and Biophysics, University of Washington, Seattle, United States
| | - Jonathan D Lautz
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States
| | - Stephen Ep Smith
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States.,Department of Pediatrics and Graduate Program in Neuroscience, University of Washington, Seattle, United States
| | - Sharona E Gordon
- Department of Physiology and Biophysics, University of Washington, Seattle, United States
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41
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Class I Phosphoinositide 3-Kinase PIK3CA/p110α and PIK3CB/p110β Isoforms in Endometrial Cancer. Int J Mol Sci 2018; 19:ijms19123931. [PMID: 30544563 PMCID: PMC6321576 DOI: 10.3390/ijms19123931] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 11/26/2018] [Accepted: 12/03/2018] [Indexed: 12/24/2022] Open
Abstract
The phosphoinositide 3-kinase (PI3K) signalling pathway is highly dysregulated in cancer, leading to elevated PI3K signalling and altered cellular processes that contribute to tumour development. The pathway is normally orchestrated by class I PI3K enzymes and negatively regulated by the phosphatase and tensin homologue, PTEN. Endometrial carcinomas harbour frequent alterations in components of the pathway, including changes in gene copy number and mutations, in particular in the oncogene PIK3CA, the gene encoding the PI3K catalytic subunit p110α, and the tumour suppressor PTEN. PIK3CB, encoding the other ubiquitously expressed class I isoform p110β, is less frequently altered but the few mutations identified to date are oncogenic. This isoform has received more research interest in recent years, particularly since PTEN-deficient tumours were found to be reliant on p110β activity to sustain transformation. In this review, we describe the current understanding of the common and distinct biochemical properties of the p110α and p110β isoforms, summarise their mutations and highlight how they are targeted in clinical trials in endometrial cancer.
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42
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Kullmann L, Krahn MP. Redundant regulation of localization and protein stability of DmPar3. Cell Mol Life Sci 2018; 75:3269-3282. [PMID: 29523893 PMCID: PMC11105499 DOI: 10.1007/s00018-018-2792-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 03/03/2018] [Accepted: 03/07/2018] [Indexed: 11/25/2022]
Abstract
Apical-basal polarity is an important characteristic of epithelia and Drosophila neural stem cells. The conserved Par complex, which consists of the atypical protein kinase C and the scaffold proteins Baz and Par6, is a key player in the establishment of apical-basal cell polarity. Membrane recruitment of Baz has been reported to be accomplished by several mechanisms, which might function in redundancy, to ensure the correct localization of the complex. However, none of the described interactions was sufficient to displace the protein from the apical junctions. Here, we dissected the role of the oligomerization domain and the lipid-binding motif of Baz in vivo in the Drosophila embryo. We found that these domains function in redundancy to ensure the apical junctional localization of Baz: inactivation of only one domain is not sufficient to disrupt the function of Baz during apical-basal polarization of epithelial cells and neural stem cells. In contrast, mutation of both domains results in a strongly impaired protein stability and a phenotype characterized by embryonic lethality and an impaired apical-basal polarity in the embryonic epithelium and neural stem cells, resembling a baz-loss of function allele. Strikingly, the binding of Baz to the transmembrane proteins E-Cadherin, Echinoid, and Starry Night was not affected in this mutant protein. Our findings reveal a redundant function of the oligomerization and the lipid-binding domain, which is required for protein stability, correct subcellular localization, and apical-basal cell polarization.
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Affiliation(s)
- Lars Kullmann
- Molecular and Cellular Anatomy, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany
- Internal Medicine D, University Hospital of Münster, Domagkstr. 3a, 48149, Münster, Germany
| | - Michael P Krahn
- Molecular and Cellular Anatomy, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany.
- Internal Medicine D, University Hospital of Münster, Domagkstr. 3a, 48149, Münster, Germany.
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43
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Chu N, Salguero AL, Liu AZ, Chen Z, Dempsey DR, Ficarro SB, Alexander WM, Marto JA, Li Y, Amzel LM, Gabelli SB, Cole PA. Akt Kinase Activation Mechanisms Revealed Using Protein Semisynthesis. Cell 2018; 174:897-907.e14. [PMID: 30078705 DOI: 10.1016/j.cell.2018.07.003] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 05/15/2018] [Accepted: 07/03/2018] [Indexed: 11/30/2022]
Abstract
Akt is a critical protein kinase that drives cancer proliferation, modulates metabolism, and is activated by C-terminal phosphorylation. The current structural model for Akt activation by C-terminal phosphorylation has centered on intramolecular interactions between the C-terminal tail and the N lobe of the kinase domain. Here, we employ expressed protein ligation to produce site-specifically phosphorylated forms of purified Akt1 that are well suited for mechanistic analysis. Using biochemical, crystallographic, and cellular approaches, we determine that pSer473-Akt activation is driven by an intramolecular interaction between the C-tail and the pleckstrin homology (PH)-kinase domain linker that relieves PH domain-mediated Akt1 autoinhibition. Moreover, dual phosphorylation at Ser477/Thr479 activates Akt1 through a different allosteric mechanism via an apparent activation loop interaction that reduces autoinhibition by the PH domain and weakens PIP3 affinity. These results provide a new framework for understanding how Akt is controlled in cell signaling and suggest distinct functions for differentially modified Akt forms.
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Affiliation(s)
- Nam Chu
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Antonieta L Salguero
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Albert Z Liu
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Zan Chen
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Daniel R Dempsey
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Scott B Ficarro
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Department of Cancer Biology and Blais Proteomics Center, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - William M Alexander
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Department of Cancer Biology and Blais Proteomics Center, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Jarrod A Marto
- Department of Cancer Biology and Blais Proteomics Center, Dana-Farber Cancer Institute, Boston, MA 02115, USA; Department of Oncologic Pathology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Yana Li
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - L Mario Amzel
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; Department of Oncology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Sandra B Gabelli
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; Department of Oncology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
| | - Philip A Cole
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; Department of Oncology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
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44
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Murthy D, Attri KS, Singh PK. Phosphoinositide 3-Kinase Signaling Pathway in Pancreatic Ductal Adenocarcinoma Progression, Pathogenesis, and Therapeutics. Front Physiol 2018; 9:335. [PMID: 29670543 PMCID: PMC5893816 DOI: 10.3389/fphys.2018.00335] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 03/19/2018] [Indexed: 12/11/2022] Open
Abstract
Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy characterized by its sudden manifestation, rapid progression, poor prognosis, and limited therapeutic options. Genetic alterations in key signaling pathways found in early pancreatic lesions are pivotal for the development and progression of pancreatic intraepithelial neoplastic lesions into invasive carcinomas. More than 90% of PDAC tumors harbor driver mutations in K-Ras that activate various downstream effector-signaling pathways, including the phosphoinositide-3-kinase (PI3K) pathway. The PI3K pathway also responds to stimuli from various growth factor receptors present on the cancer cell surface that, in turn, modulate downstream signaling cascades. Thus, the inositide signaling acts as a central node in the complex cellular signaling networks to impact cancer cell growth, motility, metabolism, and survival. Also, recent publications highlight the importance of PI3K signaling in stromal cells, whereby PI3K signaling modifies the tumor microenvironment to dictate disease outcome. The high incidence of mutations in the PI3K signaling cascade, accompanied by activation of parallel signaling pathways, makes PI3K a promising candidate for drug therapy. In this review, we describe the role of PI3K signaling in pancreatic cancer development and progression. We also discuss the crosstalk between PI3K and other major cellular signaling cascades, and potential therapeutic opportunities for targeting pancreatic ductal adenocarcinoma.
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Affiliation(s)
- Divya Murthy
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, United States
| | - Kuldeep S Attri
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, United States
| | - Pankaj K Singh
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, United States.,Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, United States.,Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE, United States.,Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, United States
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45
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Clement E, Inuzuka H, Nihira NT, Wei W, Toker A. Skp2-dependent reactivation of AKT drives resistance to PI3K inhibitors. Sci Signal 2018. [PMID: 29535262 DOI: 10.1126/scisignal.aao3810] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The PI3K-AKT kinase signaling pathway is frequently deregulated in human cancers, particularly breast cancer, where amplification and somatic mutations of PIK3CA occur with high frequency in patients. Numerous small-molecule inhibitors targeting both PI3K and AKT are under clinical evaluation, but dose-limiting toxicities and the emergence of resistance limit therapeutic efficacy. Various resistance mechanisms to PI3K inhibitors have been identified, including de novo mutations, feedback activation of AKT, or cross-talk pathways. We found a previously unknown resistance mechanism to PI3K pathway inhibition that results in AKT rebound activation. In a subset of triple-negative breast cancer cell lines, treatment with a PI3K inhibitor or depletion of PIK3CA expression ultimately promoted AKT reactivation in a manner dependent on the E3 ubiquitin ligase Skp2, the kinases IGF-1R (insulin-like growth factor 1 receptor) and PDK-1 (phosphoinositide-dependent kinase-1), and the cell growth and metabolism-regulating complex mTORC2 (mechanistic target of rapamycin complex 2), but was independent of PI3K activity or PIP3 production. Resistance to PI3K inhibitors correlated with the increased abundance of Skp2, ubiquitylation of AKT, cell proliferation in culture, and xenograft tumor growth in mice. These findings reveal a ubiquitin signaling feedback mechanism by which PI3K inhibitor resistance may emerge in aggressive breast cancer cells.
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Affiliation(s)
- Emilie Clement
- Department of Pathology, Medicine and Cancer Center, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Hiroyuki Inuzuka
- Department of Pathology, Medicine and Cancer Center, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Naoe T Nihira
- Department of Pathology, Medicine and Cancer Center, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Wenyi Wei
- Department of Pathology, Medicine and Cancer Center, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Alex Toker
- Department of Pathology, Medicine and Cancer Center, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA. .,Ludwig Center at Harvard, Harvard Medical School, Boston, MA 02215, USA
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46
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Jin EJ, Ko HR, Hwang I, Kim BS, Choi JY, Park KW, Cho SW, Ahn JY. Akt regulates neurite growth by phosphorylation-dependent inhibition of radixin proteasomal degradation. Sci Rep 2018; 8:2557. [PMID: 29416050 PMCID: PMC5803261 DOI: 10.1038/s41598-018-20755-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 01/23/2018] [Indexed: 12/20/2022] Open
Abstract
Neurite growth is controlled by a complex molecular signaling network that regulates filamentous actin (F-actin) dynamics at the growth cone. The evolutionarily conserved ezrin, radixin, and moesin family of proteins tether F-actin to the cell membrane when phosphorylated at a conserved threonine residue and modulate neurite outgrowth. Here we show that Akt binds to and phosphorylates a threonine 573 residue on radixin. Akt-mediated phosphorylation protects radixin from ubiquitin-dependent proteasomal degradation, thereby enhancing radixin protein stability, which permits proper neurite outgrowth and growth cone formation. Conversely, the inhibition of Akt kinase or disruption of Akt-dependent phosphorylation reduces the binding affinity of radixin to F-actin as well as lowers radixin protein levels, resulting in decreased neurite outgrowth and growth cone formation. Our findings suggest that Akt signaling regulates neurite outgrowth by stabilizing radixin interactions with F-actin, thus facilitating local F-actin dynamics.
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Affiliation(s)
- Eun-Ju Jin
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, 16419, Korea.,Single Cell Network Research Center, Sungkyunkwan University School of Medicine, Suwon, 16419, Korea
| | - Hyo Rim Ko
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, 16419, Korea.,Single Cell Network Research Center, Sungkyunkwan University School of Medicine, Suwon, 16419, Korea
| | - Inwoo Hwang
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, 16419, Korea.,Single Cell Network Research Center, Sungkyunkwan University School of Medicine, Suwon, 16419, Korea
| | - Byeong-Seong Kim
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, 16419, Korea
| | - Jeong-Yun Choi
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, 16419, Korea
| | - Kye Won Park
- Department of Food Science and Biotechnology, College of Biotechnology and Bioengineering, Sungkyunkwan University, Suwon, 16419, Korea
| | - Sung-Woo Cho
- Department of Biochemistry and Molecular Biology, University of Ulsan College of Medicine, Seoul, 05505, Korea
| | - Jee-Yin Ahn
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, 16419, Korea. .,Single Cell Network Research Center, Sungkyunkwan University School of Medicine, Suwon, 16419, Korea. .,Samsung Medical Center, Seoul, 06351, Korea.
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47
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Gagliardi PA, Puliafito A, Primo L. PDK1: At the crossroad of cancer signaling pathways. Semin Cancer Biol 2018; 48:27-35. [DOI: 10.1016/j.semcancer.2017.04.014] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 03/28/2017] [Accepted: 04/26/2017] [Indexed: 12/28/2022]
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48
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Michaeli L, Gottfried I, Bykhovskaia M, Ashery U. Phosphatidylinositol (4, 5)-bisphosphate targets double C2 domain protein B to the plasma membrane. Traffic 2017; 18:825-839. [PMID: 28941037 DOI: 10.1111/tra.12528] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 09/18/2017] [Accepted: 09/18/2017] [Indexed: 01/05/2023]
Abstract
Double C2 domain protein B (DOC2B) is a high-affinity Ca2+ sensor that translocates from the cytosol to the plasma membrane (PM) and promotes vesicle priming and fusion. However, the molecular mechanism underlying its translocation and targeting to the PM in living cells is not completely understood. DOC2B interacts in vitro with the PM components phosphatidylserine, phosphatidylinositol (4, 5)-bisphosphate [PI(4, 5)P2 ] and target SNAREs (t-SNAREs). Here, we show that PI(4, 5)P2 hydrolysis at the PM of living cells abolishes DOC2B translocation, whereas manipulations of t-SNAREs and other phosphoinositides have no effect. Moreover, we were able to redirect DOC2B to intracellular membranes by synthesizing PI(4, 5)P2 in those membranes. Molecular dynamics simulations and mutagenesis in the calcium and PI(4, 5)P2 -binding sites strengthened our findings, demonstrating that both calcium and PI(4, 5)P2 are required for the DOC2B-PM association and revealing multiple PI(4, 5)P2 -C2B interactions. In addition, we show that DOC2B translocation to the PM is ATP-independent and occurs in a diffusion-like manner. Our data suggest that the Ca2+ -triggered translocation of DOC2B is diffusion-driven and aimed at PI(4, 5)P2 -containing membranes.
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Affiliation(s)
- Lirin Michaeli
- Department of Neurobiology, Faculty of Life Sciences, Tel-Aviv University, Tel Aviv, Israel
| | - Irit Gottfried
- Department of Neurobiology, Faculty of Life Sciences, Tel-Aviv University, Tel Aviv, Israel
| | | | - Uri Ashery
- Department of Neurobiology, Faculty of Life Sciences, Tel-Aviv University, Tel Aviv, Israel.,Sagol School of Neuroscience, Tel-Aviv University, Tel Aviv, Israel
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49
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Das F, Ghosh-Choudhury N, Kasinath BS, Choudhury GG. Tyrosines-740/751 of PDGFRβ contribute to the activation of Akt/Hif1α/TGFβ nexus to drive high glucose-induced glomerular mesangial cell hypertrophy. Cell Signal 2017; 42:44-53. [PMID: 28951244 DOI: 10.1016/j.cellsig.2017.09.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 09/22/2017] [Indexed: 01/24/2023]
Abstract
Glomerular mesangial cell hypertrophy contributes to the complications of diabetic nephropathy. The mechanism by which high glucose induces mesangial cell hypertrophy is poorly understood. Here we explored the role of the platelet-derived growth factor receptor-β (PDGFRβ) tyrosine kinase in driving the high glucose-induced mesangial cell hypertrophy. We show that high glucose stimulates the association of the PDGFRβ with PI 3 kinase leading to tyrosine phosphorylation of the latter. High glucose-induced Akt kinase activation was also dependent upon PDGFRβ and its tyrosine phosphorylation at 740/751 residues. Inhibition of PDGFRβ activity, its downregulation and expression of its phospho-deficient (Y740/751F) mutant inhibited mesangial cell hypertrophy by high glucose. Interestingly, expression of constitutively active Akt reversed this inhibition, indicating a role of Akt kinase downstream of PDGFRβ phosphorylation in this process. The transcription factor Hif1α is a target of Akt kinase. siRNAs against Hif1α inhibited the high glucose-induced mesangial cell hypertrophy. In contrast, increased expression of Hif1α induced hypertrophy similar to high glucose. We found that inhibition of PDGFRβ and expression of PDGFRβ Y740/751F mutant significantly inhibited the high glucose-induced expression of Hif1α. Importantly, expression of Hif1α countered the inhibition of mesangial cell hypertrophy induced by siPDGFRβ or PDGFRβ Y740/751F mutant. Finally, we show that high glucose-stimulated PDGFRβ tyrosine phosphorylation at 740/751 residues and the tyrosine kinase activity of the receptor regulate the transforming growth factor-β (TGFβ) expression by Hif1α. Thus we define the cell surface PDGFRβ as a major link between high glucose and its effectors Hif1α and TGFβ for induction of diabetic mesangial cell hypertrophy.
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Affiliation(s)
- Falguni Das
- Department of Medicine, UT Health at San Antonio, TX, United States
| | - Nandini Ghosh-Choudhury
- VA Biomedical Laboratory Research, South Texas Veterans Health Care System, San Antonio, TX, United States; Department of Pathology, UT Health at San Antonio, TX, United States
| | - Balakuntalam S Kasinath
- Department of Medicine, UT Health at San Antonio, TX, United States; VA Biomedical Laboratory Research, South Texas Veterans Health Care System, San Antonio, TX, United States
| | - Goutam Ghosh Choudhury
- Department of Medicine, UT Health at San Antonio, TX, United States; VA Biomedical Laboratory Research, South Texas Veterans Health Care System, San Antonio, TX, United States; Geriatric Research, Education and Clinical Research, South Texas Veterans Health Care System, San Antonio, TX, United States.
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AKT/PKB Signaling: Navigating the Network. Cell 2017; 169:381-405. [PMID: 28431241 DOI: 10.1016/j.cell.2017.04.001] [Citation(s) in RCA: 2341] [Impact Index Per Article: 334.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Revised: 03/29/2017] [Accepted: 03/31/2017] [Indexed: 12/14/2022]
Abstract
The Ser and Thr kinase AKT, also known as protein kinase B (PKB), was discovered 25 years ago and has been the focus of tens of thousands of studies in diverse fields of biology and medicine. There have been many advances in our knowledge of the upstream regulatory inputs into AKT, key multifunctional downstream signaling nodes (GSK3, FoxO, mTORC1), which greatly expand the functional repertoire of AKT, and the complex circuitry of this dynamically branching and looping signaling network that is ubiquitous to nearly every cell in our body. Mouse and human genetic studies have also revealed physiological roles for the AKT network in nearly every organ system. Our comprehension of AKT regulation and functions is particularly important given the consequences of AKT dysfunction in diverse pathological settings, including developmental and overgrowth syndromes, cancer, cardiovascular disease, insulin resistance and type 2 diabetes, inflammatory and autoimmune disorders, and neurological disorders. There has also been much progress in developing AKT-selective small molecule inhibitors. Improved understanding of the molecular wiring of the AKT signaling network continues to make an impact that cuts across most disciplines of the biomedical sciences.
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