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Maffucci T, Falasca M. Signalling Properties of Inositol Polyphosphates. Molecules 2020; 25:molecules25225281. [PMID: 33198256 PMCID: PMC7696153 DOI: 10.3390/molecules25225281] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 11/02/2020] [Accepted: 11/04/2020] [Indexed: 12/16/2022] Open
Abstract
Several studies have identified specific signalling functions for inositol polyphosphates (IPs) in different cell types and have led to the accumulation of new information regarding their cellular roles as well as new insights into their cellular production. These studies have revealed that interaction of IPs with several proteins is critical for stabilization of protein complexes and for modulation of enzymatic activity. This has not only revealed their importance in regulation of several cellular processes but it has also highlighted the possibility of new pharmacological interventions in multiple diseases, including cancer. In this review, we describe some of the intracellular roles of IPs and we discuss the pharmacological opportunities that modulation of IPs levels can provide.
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Affiliation(s)
- Tania Maffucci
- Centre for Cell Biology and Cutaneous Research, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, UK
- Correspondence: (T.M.); (M.F.); Tel.: +61-08-92669712 (M.F.)
| | - Marco Falasca
- School of Pharmacy and Biomedical Sciences, CHIRI, Curtin University, Perth 6102, Australia
- Correspondence: (T.M.); (M.F.); Tel.: +61-08-92669712 (M.F.)
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Maffucci T, Falasca M. Inositol Polyphosphate-Based Compounds as Inhibitors of Phosphoinositide 3-Kinase-Dependent Signaling. Int J Mol Sci 2020; 21:E7198. [PMID: 33003448 PMCID: PMC7582811 DOI: 10.3390/ijms21197198] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 09/21/2020] [Accepted: 09/21/2020] [Indexed: 02/07/2023] Open
Abstract
Signaling pathways regulated by the phosphoinositide 3-kinase (PI3K) enzymes have a well-established role in cancer development and progression. Over the past 30 years, the therapeutic potential of targeting this pathway has been well recognized, and this has led to the development of a multitude of drugs, some of which have progressed into clinical trials, with few of them currently approved for use in specific cancer settings. While many inhibitors compete with ATP, hence preventing the catalytic activity of the kinases directly, a deep understanding of the mechanisms of PI3K-dependent activation of its downstream effectors led to the development of additional strategies to prevent the initiation of this signaling pathway. This review summarizes previously published studies that led to the identification of inositol polyphosphates as promising parent molecules to design novel inhibitors of PI3K-dependent signals. We focus our attention on the inhibition of protein-membrane interactions mediated by binding of pleckstrin homology domains and phosphoinositides that we proposed 20 years ago as a novel therapeutic strategy.
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Affiliation(s)
- Tania Maffucci
- Centre for Cell Biology and Cutaneous Research, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, UK
| | - Marco Falasca
- Metabolic Signalling Group, School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute, Curtin University, Perth, WA 6102, Australia
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Ceccato L, Mansat M, Payrastre B, Gaits-Iacovoni F, Viaud J. Protein-Lipid Interaction by Fluorescence (PLIF) to Characterize and Screen for Inhibitors of Protein-Phosphoinositide Interactions. CURRENT PROTOCOLS IN PROTEIN SCIENCE 2017; 89:19.31.1-19.31.10. [PMID: 28762494 DOI: 10.1002/cpps.35] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Phosphoinositides are key signaling and regulatory phospholipids that mediate important pathophysiological processes. This is achieved through the interaction of their phosphorylated inositol head group with a wide range of protein domains. Therefore, being able to determine the phosphoinositide specificity for effector protein is essential to the understanding of its cellular function. This unit describes a novel method named Protein-Lipid Interaction by Fluorescence, or PLIF. PLIF is a fast, reliable and high throughput assay that allows determination of the phosphoinositide specificity of proteins, simultaneously providing relative affinities. In addition, PLIF is suitable for screening inhibitors of protein- phosphoinositide interaction, allowing identification of potential pharmacological compounds. © 2017 by John Wiley & Sons, Inc.
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Affiliation(s)
- Laurie Ceccato
- INSERM U1048 and Université Toulouse 3, Toulouse, France
| | - Mélanie Mansat
- INSERM U1048 and Université Toulouse 3, Toulouse, France
| | - Bernard Payrastre
- INSERM U1048 and Université Toulouse 3, Toulouse, France.,CHU (Centre Hospitalier Universitaire) de Toulouse, Laboratoire d'Hématologie, France
| | | | - Julien Viaud
- INSERM U1048 and Université Toulouse 3, Toulouse, France
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A Small Molecule Inhibitor of PDK1/PLCγ1 Interaction Blocks Breast and Melanoma Cancer Cell Invasion. Sci Rep 2016; 6:26142. [PMID: 27199173 PMCID: PMC4873738 DOI: 10.1038/srep26142] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 04/21/2016] [Indexed: 12/02/2022] Open
Abstract
Strong evidence suggests that phospholipase Cγ1 (PLCγ1) is a suitable target to counteract tumourigenesis and metastasis dissemination. We recently identified a novel signalling pathway required for PLCγ1 activation which involves formation of a protein complex with 3-phosphoinositide-dependent protein kinase 1 (PDK1). In an effort to define novel strategies to inhibit PLCγ1-dependent signals we tested here whether a newly identified and highly specific PDK1 inhibitor, 2-O-benzyl-myo-inositol 1,3,4,5,6-pentakisphosphate (2-O-Bn-InsP5), could affect PDK1/PLCγ1 interaction and impair PLCγ1-dependent cellular functions in cancer cells. Here, we demonstrate that 2-O-Bn-InsP5 interacts specifically with the pleckstrin homology domain of PDK1 and impairs formation of a PDK1/PLCγ1 complex. 2-O-Bn-InsP5 is able to inhibit the epidermal growth factor-induced PLCγ1 phosphorylation and activity, ultimately resulting in impaired cancer cell migration and invasion. Importantly, we report that 2-O-Bn-InsP5 inhibits cancer cell dissemination in zebrafish xenotransplants. This work demonstrates that the PDK1/PLCγ1 complex is a potential therapeutic target to prevent metastasis and it identifies 2-O-Bn-InsP5 as a leading compound for development of anti-metastatic drugs.
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Ceccato L, Chicanne G, Nahoum V, Pons V, Payrastre B, Gaits-Iacovoni F, Viaud J. PLIF: A rapid, accurate method to detect and quantitatively assess protein-lipid interactions. Sci Signal 2016; 9:rs2. [PMID: 27025878 DOI: 10.1126/scisignal.aad4337] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Phosphoinositides are a type of cellular phospholipid that regulate signaling in a wide range of cellular and physiological processes through the interaction between their phosphorylated inositol head group and specific domains in various cytosolic proteins. These lipids also influence the activity of transmembrane proteins. Aberrant phosphoinositide signaling is associated with numerous diseases, including cancer, obesity, and diabetes. Thus, identifying phosphoinositide-binding partners and the aspects that define their specificity can direct drug development. However, current methods are costly, time-consuming, or technically challenging and inaccessible to many laboratories. We developed a method called PLIF (for "protein-lipid interaction by fluorescence") that uses fluorescently labeled liposomes and tethered, tagged proteins or peptides to enable fast and reliable determination of protein domain specificity for given phosphoinositides in a membrane environment. We validated PLIF against previously known phosphoinositide-binding partners for various proteins and obtained relative affinity profiles. Moreover, PLIF analysis of the sorting nexin (SNX) family revealed not only that SNXs bound most strongly to phosphatidylinositol 3-phosphate (PtdIns3P or PI3P), which is known from analysis with other methods, but also that they interacted with other phosphoinositides, which had not previously been detected using other techniques. Different phosphoinositide partners, even those with relatively weak binding affinity, could account for the diverse functions of SNXs in vesicular trafficking and protein sorting. Because PLIF is sensitive, semiquantitative, and performed in a high-throughput manner, it may be used to screen for highly specific protein-lipid interaction inhibitors.
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Affiliation(s)
- Laurie Ceccato
- INSERM, U1048 and Université Toulouse 3, I2MC, Avenue Jean Poulhès BP84225, 31432 Toulouse Cedex 04, France
| | - Gaëtan Chicanne
- INSERM, U1048 and Université Toulouse 3, I2MC, Avenue Jean Poulhès BP84225, 31432 Toulouse Cedex 04, France
| | - Virginie Nahoum
- CNRS, Institut de Pharmacologie et de Biologie Structurale (IPBS), 31000 Toulouse, France. Université de Toulouse, UPS (Université Paul Sabatier), IPBS, 31000 Toulouse, France
| | - Véronique Pons
- INSERM, U1048 and Université Toulouse 3, I2MC, Avenue Jean Poulhès BP84225, 31432 Toulouse Cedex 04, France
| | - Bernard Payrastre
- INSERM, U1048 and Université Toulouse 3, I2MC, Avenue Jean Poulhès BP84225, 31432 Toulouse Cedex 04, France. CHU (Centre Hospitalier Universitaire) de Toulouse, Laboratoire d'Hématologie, 31059 Toulouse Cedex 03, France
| | - Frédérique Gaits-Iacovoni
- INSERM, U1048 and Université Toulouse 3, I2MC, Avenue Jean Poulhès BP84225, 31432 Toulouse Cedex 04, France
| | - Julien Viaud
- INSERM, U1048 and Université Toulouse 3, I2MC, Avenue Jean Poulhès BP84225, 31432 Toulouse Cedex 04, France.
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Role of phosphatidylinositol 3,4,5-trisphosphate in cell signaling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 991:105-39. [PMID: 23775693 DOI: 10.1007/978-94-007-6331-9_7] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Many lipids present in cellular membranes are phosphorylated as part of signaling cascades and participate in the recruitment, localization, and activation of downstream protein effectors. Phosphatidylinositol (3,4,5)-trisphosphate (PtdIns(3,4,5)P3) is one of the most important second messengers and is capable of interacting with a variety of proteins through specific PtdIns(3,4,5)P3 binding domains. Localization and activation of these effector proteins controls a myriad of cellular functions including cell survival, proliferation, cytoskeletal rearrangement, and gene expression. Aberrations in the production and metabolism of PtdIns(3,4,5)P3 have been implicated in many human diseases including cancer, diabetes, inflammation, and heart disease. This chapter provides an overview of the role of PtdIns(3,4,5)P3 in cellular regulation and the implications of PtdIns(3,4,5)P3 dysregulation in human diseases. Additionally, recent attempts at targeting PtdIns(3,4,5)P3 signaling via small molecule inhibitors are summarized.
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Rosen SAJ, Gaffney PRJ, Spiess B, Gould IR. Understanding the relative affinity and specificity of the pleckstrin homology domain of protein kinase B for inositol phosphates. Phys Chem Chem Phys 2012; 14:929-36. [DOI: 10.1039/c1cp22240f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Song F, Zhang J, Zhao Y, Chen W, Li L, Xi Z. Synthesis and antitumor activity of inositol phosphotriester analogues. Org Biomol Chem 2012; 10:3642-54. [DOI: 10.1039/c2ob00031h] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Meuillet EJ. Novel inhibitors of AKT: assessment of a different approach targeting the pleckstrin homology domain. Curr Med Chem 2011; 18:2727-42. [PMID: 21649580 DOI: 10.2174/092986711796011292] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Accepted: 05/13/2011] [Indexed: 12/21/2022]
Abstract
Protein kinase B/AKT plays a central role in cancer. The serine/threonine kinase is overexpressed or constitutively active in many cancers and has been validated as a therapeutic target for cancer treatment. However, targeting the kinase activity has revealed itself to be a challenge due to non-selectivity of the compounds towards other kinases. This review summarizes other approaches scientists have developed to inhibit the activity and function of AKT. They consist in targeting the pleckstrin homology (PH) domain of AKT. Indeed, upon the generation of 3-phosphorylated phosphatidylinositol phosphates (PI3Ps) by PI3-kinase (PI3K), AKT translocates from the cytosol to the plasma membrane and binds to the PI3Ps via its PH domain. Thus, several analogs of PI3Ps (PI Analogs or PIAs), alkylphospholipids (APLs), such as edelfosine or inositol phophates (IPs) have been described that inhibit the binding of the PH domain to PI3Ps. Recent allostertic inhibitors and small molecules that do not bind the kinase domain but affect the kinase activity of AKT, presumably by interacting with the PH domain, have been also identified. Finally, several drug screening studies spawned novel chemical scaffolds that bind the PH domain of AKT. Together, these approaches have been more or less sucessfull in vitro and to some extent translated in preclinical studies. Several of these new AKT PH domain inhibitors exhibit promising anti-tumor activity in mouse models and some of them show synergy with ionizing radiation and chemotherapy. Early clinical trials have started and results will attest to the validity and efficacy of such approaches in the near future.
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Affiliation(s)
- E J Meuillet
- Department of Nutritional Sciences, The University of Arizona, Tucson, Arizona, USA.
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Abstract
The phosphoinositide 3-kinase (PI3K) signaling pathway controls a wide variety of cellular processes including cell death and survival, cell migration, protein synthesis and metabolism. Aberrant PI3K-dependent signaling, mediated by Akt kinase, has been implicated in many human diseases including cancer, inflammation, cardiovascular disease and metabolic diseases, making this pathway a principle target for drug development. In this article we will summarize the PI3K signaling network and discuss current strategies for pathway inhibition. We will also explore the importance and emerging relevance of Akt-independent PI3K signaling pathways and discuss attempts being made to harness these pathways by inhibiting the binding of a product of PI3K, phosphatidylinositol-(3,4,5)-trisphosphate, to effector pleckstrin homology domains.
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Ahad AM, Zuohe S, Du-Cuny L, Moses SA, Zhou LL, Zhang S, Powis G, Meuillet EJ, Mash EA. Development of sulfonamide AKT PH domain inhibitors. Bioorg Med Chem 2011; 19:2046-54. [PMID: 21353784 DOI: 10.1016/j.bmc.2011.01.049] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 01/20/2011] [Accepted: 01/24/2011] [Indexed: 01/08/2023]
Abstract
Disruption of the phosphatidylinositol 3-kinase/AKT signaling pathway can lead to apoptosis in cancer cells. Previously we identified a lead sulfonamide that selectively bound to the pleckstrin homology (PH) domain of AKT and induced apoptosis when present at low micromolar concentrations. To examine the effects of structural modification, a set of sulfonamides related to the lead compound was designed, synthesized, and tested for binding to the expressed PH domain of AKT using a surface plasmon resonance-based competitive binding assay. Cellular activity was determined by means of an assay for pAKT production and a cell killing assay using BxPC-3 cells. The most active compounds in the set are lipophilic and possess an aliphatic chain of the proper length. Results were interpreted with the aid of computational modeling. This paper represents the first structure-activity relationship (SAR) study of a large family of AKT PH domain inhibitors. Information obtained will be used in the design of the next generation of inhibitors of AKT PH domain function.
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Affiliation(s)
- Ali Md Ahad
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721-0041, USA
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Falasca M, Chiozzotto D, Godage HY, Mazzoletti M, Riley AM, Previdi S, Potter BVL, Broggini M, Maffucci T. A novel inhibitor of the PI3K/Akt pathway based on the structure of inositol 1,3,4,5,6-pentakisphosphate. Br J Cancer 2010; 102:104-14. [PMID: 20051961 PMCID: PMC2813745 DOI: 10.1038/sj.bjc.6605408] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Owing to its role in cancer, the phosphoinositide 3-kinase (PI3K)/Akt pathway is an attractive target for therapeutic intervention. We previously reported that the inhibition of Akt by inositol 1,3,4,5,6-pentakisphosphate (InsP(5)) results in anti-tumour properties. To further develop this compound we modified its structure to obtain more potent inhibitors of the PI3K/Akt pathway. METHODS Cell proliferation/survival was determined by cell counting, sulphorhodamine or acridine orange/ethidium bromide assay; Akt activation was determined by western blot analysis. In vivo effect of compounds was tested on PC3 xenografts, whereas in vitro activity on kinases was determined by SelectScreen Kinase Profiling Service. RESULTS The derivative 2-O-benzyl-myo-inositol 1,3,4,5,6-pentakisphosphate (2-O-Bn-InsP(5)) is active towards cancer types resistant to InsP(5) in vitro and in vivo. 2-O-Bn-InsP(5) possesses higher pro-apoptotic activity than InsP(5) in sensitive cells and enhances the effect of anti-cancer compounds. 2-O-Bn-InsP(5) specifically inhibits 3-phosphoinositide-dependent protein kinase 1 (PDK1) in vitro (IC(50) in the low nanomolar range) and the PDK1-dependent phosphorylation of Akt in cell lines and excised tumours. It is interesting to note that 2-O-Bn-InsP(5) also inhibits the mammalian target of rapamycin (mTOR) in vitro. CONCLUSIONS InsP(5) and 2-O-Bn-InsP(5) may represent lead compounds to develop novel inhibitors of the PI3K/Akt pathway (including potential dual PDK1/mTOR inhibitors) and novel potential anti-cancer drugs.
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Affiliation(s)
- M Falasca
- Queen Mary University of London, Barts and The London School of Medicine and Dentistry, Blizard Institute of Cell and Molecular Science, Centre for Diabetes, Inositide Signalling Group, 4 Newark Street, London E1 2AT, UK.
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Maffucci T, Piccolo E, Cumashi A, Iezzi M, Riley AM, Saiardi A, Godage HY, Rossi C, Broggini M, Iacobelli S, Potter BVL, Innocenti P, Falasca M. Inhibition of the phosphatidylinositol 3-kinase/Akt pathway by inositol pentakisphosphate results in antiangiogenic and antitumor effects. Cancer Res 2005; 65:8339-49. [PMID: 16166311 DOI: 10.1158/0008-5472.can-05-0121] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The purpose of this study was to investigate the antiangiogenic and in vivo properties of the recently identified phosphatidylinositol 3-kinase (PI3K)/Akt inhibitor Inositol(1,3,4,5,6) pentakisphosphate [Ins(1,3,4,5,6)P5]. Because activation of the PI3K/Akt pathway is a crucial step in some of the events leading to angiogenesis, the effect of Ins(1,3,4,5,6)P5 on basic fibroblast growth factor (FGF-2)-induced Akt phosphorylation, cell survival, motility, and tubulogenesis in vitro was tested in human umbilical vein endothelial cells (HUVEC). The effect of Ins(1,3,4,5,6)P5 on FGF-2-induced angiogenesis in vivo was evaluated using s.c. implanted Matrigel in mice. In addition, the effect of Ins(1,3,4,5,6)P5 on growth of ovarian carcinoma SKOV-3 xenograft was tested. Here, we show that FGF-2 induces Akt phosphorylation in HUVEC resulting in antiapoptotic effect in serum-deprived cells and increase in cellular motility. Ins(1,3,4,5,6)P5 blocks FGF-2-mediated Akt phosphorylation and inhibits both survival and migration in HUVEC. Moreover, Ins(1,3,4,5,6)P5 inhibits the FGF-2-mediated capillary tube formation of HUVEC plated on Matrigel and the FGF-2-induced angiogenic reaction in BALB/c mice. Finally, Ins(1,3,4,5,6)P5 blocks the s.c. growth of SKOV-3 xenografted in nude mice to the same extent than cisplatin and it completely inhibits Akt phosphorylation in vivo. These data definitively identify the Akt inhibitor Ins(1,3,4,5,6)P5 as a specific antiangiogenic and antitumor factor. Inappropriate activation of the PI3K/Akt pathway has been linked to the development of several diseases, including cancer, making this pathway an attractive target for therapeutic strategies. In this respect, Ins(1,3,4,5,6)P5, a water-soluble, natural compound with specific proapoptotic and antiangiogenic properties, might result in successful anticancer therapeutic strategies.
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Affiliation(s)
- Tania Maffucci
- Department of Medicine, The Sackler Institute, University College London, United Kingdom
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Piccolo E, Vignati S, Maffucci T, Innominato PF, Riley AM, Potter BVL, Pandolfi PP, Broggini M, Iacobelli S, Innocenti P, Falasca M. Inositol pentakisphosphate promotes apoptosis through the PI 3-K/Akt pathway. Oncogene 2004; 23:1754-65. [PMID: 14755253 DOI: 10.1038/sj.onc.1207296] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Phosphoinositide 3-kinase (PI 3-K) is implicated in a wide array of biological and pathophysiological responses, including tumorigenesis, invasion and metastasis, therefore specific inhibitors of the kinase may prove useful in cancer therapy. We propose that specific inositol polyphosphates have the potential to antagonize the activation of PI 3-K pathways by competing with the binding of PtdIns(3,4,5)P3 to pleckstrin homology (PH) domains. Here we show that Ins(1,3,4,5,6)P5 inhibits the serine phosphorylation and the kinase activity of Akt/PKB. As a consequence of this inhibition, Ins(1,3,4,5,6)P5 induces apoptosis in ovarian, lung and breast cancer cells. Overexpression of constitutively active Akt protects SKBR-3 cells from Ins(1,3,4,5,6)P5-induced apoptosis. Furthermore, Ins(1,3,4,5,6)P5 enhances the proapoptotic effect of cisplatin and etoposide in ovarian and lung cancer cells, respectively. These results support a role for Ins(1,3,4,5,6)P5 as a specific inhibitor of the PI 3-K/Akt signalling pathway, that may sensitize cancer cells to the action of commonly used anticancer drugs.
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Affiliation(s)
- Enza Piccolo
- Department of Medicine, The Sackler Institute, University College London, 5, University Street, London WC1E 6JJ, UK
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Hartel-Schenk S, Gratchev A, Hanski ML, Ogorek D, Trendelenburg G, Hummel M, Höpfner M, Scherübl H, Zeitz M, Hanski C. Novel adapter protein AP162 connects a sialyl-Le(x)-positive mucin with an apoptotic signal transduction pathway. Glycoconj J 2001; 18:915-23. [PMID: 12820725 DOI: 10.1023/a:1022256610674] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Glycoproteins modified with a sialyl-Le(x)-moiety are important sensors for extracellular signals regulating cellular recognition, adhesion and migration. The transduction pathways and signals mediated by these glycoproteins within the cell are largely unknown. In search of novel glycoproteins modified with sialyl-Le(x)-moiety, we screened a human colonic cDNA expression library with a rabbit antiserum produced against sialyl-Le(x)-positive mucins. The antiserum detected a new protein, named B2, which was cloned and characterised in detail. The analysis of the B2 gene revealed a 5.7 kb RNA transcript detectable in all investigated tissues and a complete coding sequence of 2778 bp. The B2 protein exhibited two putative PH (pleckstrin homology) domains and a leucine zipper motif but no homology to any known proteins. Monospecific antibodies against the B2-protein precipitated from the solubilised membrane fraction of the colon carcinoma cell line LS 174T a protein with an apparent Mr = 162 kDa and, additionally, a mucin-like glycoprotein with an apparent Mr = 220 kDa. Protein fractionation on a CsCl gradient, Western blots and sandwich ELISA showed that the 220 kDa mucin carries the sialyl-Le(x) moiety and is tightly bound to the 162 kDa protein. The expression of the recombinant B2-protein enhanced staurosporine-induced apoptosis in epithelial cancer cell lines. These data indicate that B2 is a novel, ubiquitously expressed protein with a putative adapter function. The protein has been named AP162 (adapter protein 162). In colon carcinoma cells B2-protein is tightly associated with a sialyl-Le(x)-positive mucin and has a potential for involvement in sialyl-Le(x)-mediated transduction of apoptotic signals.
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Affiliation(s)
- S Hartel-Schenk
- Department of Gastroenterology, University Clinic Benjamin Franklin Free University Berlin, 12200 Berlin, Hindenburgdamm 30, Germany
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16
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Abstract
Over the past ten years, our knowledge of the integral role that the phospho-inositide 3-kinases (PI3Ks) and their 3'-phosphorylated lipid products (3'-phosphorylated phosphoinositides; 3P-PIs) play in the mediation of signal transduction, cytoskeletal rearrangements and membrane trafficking has expanded considerably. They are now known to be involved in the regulation of cell growth, differentiation, mobility, proliferation and survival and hence they have become a potential target for the control of the growth and spread of cancer cells. More recently, the correlation of the multiplicity of isomers (both catalytic and regulatory) within the different classes of the PI3Ks with their functional relevance has become possible. This, combined with our further understanding of the protein recognition patterns for their different 3P-PIs and the newly-described pathways in the control of the levels of these by dephosphorylation, has provided new aspects and areas for interference in these multiple PI3K signalling pathways. However, in the search for effective, non-toxic, drugs for use in the treatment of cancers, these individual targets for PI3K inhibition need to be further correlated with the specific in vivo effects on cell survival, invasivity and metastatic potential. Here, the range of PI3K inhibition targets are discussed in the light of recent experimental findings, with a view to the exploitation of their specificities in new approaches to effective cancer treatments based on PI3K activity inhibition.
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Affiliation(s)
- C P Berrie
- Department of Cell Biology and Oncology, Istituto di Ricerche Farmacologiche Mario Negri, Consorzio Mrio Negri Sud, Santa Maria Imbaro, Chieti, Italy.
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Blum-Held C, Bernard P, Schlewer G, Spiess B. myo-Inositol 1,4,5,6-tetrakisphosphate and myo-inositol 3,4,5,6-tetrakisphosphate, two second messengers that may act as pH-dependent molecular switches. J Am Chem Soc 2001; 123:3399-400. [PMID: 11457089 DOI: 10.1021/ja015616i] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- C Blum-Held
- Laboratoire de Pharmacologie Moléculaire UMR 7081 du CNRS-ULP, Faculté de Pharmacie 74, Route du Rhin, B.P. 24, 67401 Illkirch Cedex, France
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