1
|
Li H, Wen X, Ren Y, Fan Z, Zhang J, He G, Fu L. Targeting PI3K family with small-molecule inhibitors in cancer therapy: current clinical status and future directions. Mol Cancer 2024; 23:164. [PMID: 39127670 DOI: 10.1186/s12943-024-02072-1] [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: 06/15/2024] [Accepted: 07/25/2024] [Indexed: 08/12/2024] Open
Abstract
The Phosphatidylinositol-3-kinase (PI3K) family is well-known to comprise three classes of intracellular enzymes. Class I PI3Ks primarily function in signaling by responding to cell surface receptor stimulation, while class II and III are more involved in membrane transport. Under normal physiological conditions, the PI3K signaling network orchestrates cell growth, division, migration and survival. Aberrant activation of the PI3K signaling pathway disrupts cellular activity and metabolism, often marking the onset of cancer. Currently, the Food and Drug Administration (FDA) has approved the clinical use of five class I PI3K inhibitors. These small-molecule inhibitors, which exhibit varying selectivity for different class I PI3K family members, are primarily used in the treatment of breast cancer and hematologic malignancies. Therefore, the development of novel class I PI3K inhibitors has been a prominent research focus in the field of oncology, aiming to enhance potential therapeutic selectivity and effectiveness. In this review, we summarize the specific structures of PI3Ks and their functional roles in cancer progression. Additionally, we critically evaluate small molecule inhibitors that target class I PI3K, with a particular focus on their clinical applications in cancer treatment. Moreover, we aim to analyze therapeutic approaches for different types of cancers marked by aberrant PI3K activation and to identify potential molecular targets amenable to intervention with small-molecule inhibitors. Ultimately, we propose future directions for the development of therapeutic strategies that optimize cancer treatment outcomes by modulating the PI3K family.
Collapse
Affiliation(s)
- Hongyao Li
- Institute of Precision Drug Innovation and Cancer Center, the Second Hospital of Dalian Medical University, Dalian, 116023, China
- Sichuan Engineering Research Center for Biomimetic Synthesis of Natural Drugs, School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, China
- Department of Dermatology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Sichuan University, Chengdu, 610041, China
| | - Xiang Wen
- Department of Dermatology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Sichuan University, Chengdu, 610041, China
| | - Yueting Ren
- Department of Dermatology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Sichuan University, Chengdu, 610041, China
- Department of Brain Science, Faculty of Medicine, Imperial College, London, SW72AZ, UK
| | - Zhichao Fan
- Institute of Precision Drug Innovation and Cancer Center, the Second Hospital of Dalian Medical University, Dalian, 116023, China
- Sichuan Engineering Research Center for Biomimetic Synthesis of Natural Drugs, School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, China
- Department of Dermatology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Sichuan University, Chengdu, 610041, China
| | - Jin Zhang
- School of Pharmaceutical Sciences of Medical School, Shenzhen University, Shenzhen, 518000, China.
| | - Gu He
- Department of Dermatology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Sichuan University, Chengdu, 610041, China.
| | - Leilei Fu
- Institute of Precision Drug Innovation and Cancer Center, the Second Hospital of Dalian Medical University, Dalian, 116023, China.
- Sichuan Engineering Research Center for Biomimetic Synthesis of Natural Drugs, School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, China.
| |
Collapse
|
2
|
Bastos IM, Rebelo S, Silva VLM. A comprehensive review on phosphatidylinositol-3-kinase (PI3K) and its inhibitors bearing pyrazole or indazole core for cancer therapy. Chem Biol Interact 2024; 398:111073. [PMID: 38823538 DOI: 10.1016/j.cbi.2024.111073] [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: 04/29/2024] [Accepted: 05/27/2024] [Indexed: 06/03/2024]
Abstract
Cancer is a complex and multifaceted group of diseases with a high mortality rate characterized by uncontrolled proliferation of abnormal cells. Dysregulation of normal signalling pathways in cancer contributes to the different hallmarks of this disease. The signalling pathway of which phosphatidylinositol 3-kinase (PI3K) is a part is not an exception. In fact, dysregulated activation of PI3K signalling pathways can result in unbridled cellular proliferation and enhanced cell survival, thereby fostering the onset and advancement of cancer. Therefore, there is substantial interest in developing targeted therapies specifically aimed at inhibiting the PI3K enzyme and its associated pathways. Also, the therapeutic interest on pyrazoles and indazoles has been growing due to their various medicinal properties, namely, anticancer activity. Derivatives of these compounds have been studied as PI3K inhibitors, and they showed promising results. There are already some PI3K inhibitors approved by Food and Drug Administration (FDA), such as Idelalisib (Zydelig®) and Alpelisib (Piqray®). In this context, this review aims to address the importance of PI3K in cellular processes and its role in cancer. Additionally, it aims to report a comprehensive literature review of PI3K inhibitors, containing the pyrazole and indazole scaffolds, published in the last fifteen years, focusing on structure-activity relationship aspects, thus providing important insights for the design of novel and more effective PI3K inhibitors.
Collapse
Affiliation(s)
- Inês M Bastos
- LAQV-REQUIMTE and Department of Chemistry, University of Aveiro, 3810-193, Aveiro, Portugal
| | - Sandra Rebelo
- Institute of Biomedicine-iBiMED, Department of Medical Sciences, University of Aveiro, 3810-193, Aveiro, Portugal
| | - Vera L M Silva
- LAQV-REQUIMTE and Department of Chemistry, University of Aveiro, 3810-193, Aveiro, Portugal.
| |
Collapse
|
3
|
Kücükdisli M, Bel-Abed H, Cirillo D, Lo WT, Efrém NL, Horatscheck A, Perepelittchenko L, Prokofeva P, Ehret TAL, Radetzki S, Neuenschwander M, Specker E, Médard G, Müller S, Wilhelm S, Kuster B, von Kries JP, Haucke V, Nazaré M. Structural Basis for Highly Selective Class II Alpha Phosphoinositide-3-Kinase Inhibition. J Med Chem 2023; 66:14278-14302. [PMID: 37819647 DOI: 10.1021/acs.jmedchem.3c01319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/13/2023]
Abstract
Class II phosphoinositide-3-kinases (PI3Ks) play central roles in cell signaling, division, migration, and survival. Despite evidence that all PI3K class II isoforms serve unique cellular functions, the lack of isoform-selective inhibitors severely hampers the systematic investigation of their potential relevance as pharmacological targets. Here, we report the structural evaluation and molecular determinants for selective PI3K-C2α inhibition by a structure-activity relationship study based on a pteridinone scaffold, leading to the discovery of selective PI3K-C2α inhibitors called PITCOINs. Cocrystal structures and docking experiments supported the rationalization of the structural determinants essential for inhibitor activity and high selectivity. Profiling of PITCOINs in a panel of more than 118 diverse kinases showed no off-target kinase inhibition. Notably, by addressing a selectivity pocket, PITCOIN4 showed nanomolar inhibition of PI3K-C2α and >100-fold selectivity in a general kinase panel. Our study paves the way for the development of novel therapies for diseases related to PI3K-C2α function.
Collapse
Affiliation(s)
- Murat Kücükdisli
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Campus Berlin-Buch, 13125 Berlin, Germany
| | - Hassen Bel-Abed
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Campus Berlin-Buch, 13125 Berlin, Germany
| | - Davide Cirillo
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Campus Berlin-Buch, 13125 Berlin, Germany
| | - Wen-Ting Lo
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Campus Berlin-Buch, 13125 Berlin, Germany
| | - Nina-Louisa Efrém
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Campus Berlin-Buch, 13125 Berlin, Germany
| | - André Horatscheck
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Campus Berlin-Buch, 13125 Berlin, Germany
| | - Liudmila Perepelittchenko
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Campus Berlin-Buch, 13125 Berlin, Germany
| | - Polina Prokofeva
- Chair of Proteomics and Bioanalytics, Technical University of Munich, 85354 Freising, Germany
| | - Theresa A L Ehret
- Institute of Pharmaceutical Chemistry, Johann Wolfgang Goethe University, Max-von-Laue-Str. 9, 60438 Frankfurt am Main, Germany
- Buchmann Institute for Molecular Life Sciences and Structural Genomics Consortium (SGC), Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany
| | - Silke Radetzki
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Campus Berlin-Buch, 13125 Berlin, Germany
| | - Martin Neuenschwander
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Campus Berlin-Buch, 13125 Berlin, Germany
| | - Edgar Specker
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Campus Berlin-Buch, 13125 Berlin, Germany
| | - Guillaume Médard
- Chair of Proteomics and Bioanalytics, Technical University of Munich, 85354 Freising, Germany
| | - Susanne Müller
- Institute of Pharmaceutical Chemistry, Johann Wolfgang Goethe University, Max-von-Laue-Str. 9, 60438 Frankfurt am Main, Germany
- Buchmann Institute for Molecular Life Sciences and Structural Genomics Consortium (SGC), Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany
| | - Stephanie Wilhelm
- Chair of Proteomics and Bioanalytics, Technical University of Munich, 85354 Freising, Germany
| | - Bernhard Kuster
- Chair of Proteomics and Bioanalytics, Technical University of Munich, 85354 Freising, Germany
| | - Jens Peter von Kries
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Campus Berlin-Buch, 13125 Berlin, Germany
| | - Volker Haucke
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Campus Berlin-Buch, 13125 Berlin, Germany
| | - Marc Nazaré
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Campus Berlin-Buch, 13125 Berlin, Germany
| |
Collapse
|
4
|
Safaroghli-Azar A, Sanaei MJ, Pourbagheri-Sigaroodi A, Bashash D. Phosphoinositide 3-kinase (PI3K) classes: From cell signaling to endocytic recycling and autophagy. Eur J Pharmacol 2023:175827. [PMID: 37269974 DOI: 10.1016/j.ejphar.2023.175827] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 05/19/2023] [Accepted: 05/31/2023] [Indexed: 06/05/2023]
Abstract
Lipid signaling is defined as any biological signaling action in which a lipid messenger binds to a protein target, converting its effects to specific cellular responses. In this complex biological pathway, the family of phosphoinositide 3-kinase (PI3K) represents a pivotal role and affects many aspects of cellular biology from cell survival, proliferation, and migration to endocytosis, intracellular trafficking, metabolism, and autophagy. While yeasts have a single isoform of phosphoinositide 3-kinase (PI3K), mammals possess eight PI3K types divided into three classes. The class I PI3Ks have set the stage to widen research interest in the field of cancer biology. The aberrant activation of class I PI3Ks has been identified in 30-50% of human tumors, and activating mutations in PIK3CA is one of the most frequent oncogenes in human cancer. In addition to indirect participation in cell signaling, class II and III PI3Ks primarily regulate vesicle trafficking. Class III PI3Ks are also responsible for autophagosome formation and autophagy flux. The current review aims to discuss the original data obtained from international research laboratories on the latest discoveries regarding PI3Ks-mediated cell biological processes. Also, we unravel the mechanisms by which pools of the same phosphoinositides (PIs) derived from different PI3K types act differently.
Collapse
Affiliation(s)
- Ava Safaroghli-Azar
- Department of Hematology and Blood Banking, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad-Javad Sanaei
- Department of Hematology and Blood Banking, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Atieh Pourbagheri-Sigaroodi
- Department of Hematology and Blood Banking, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Davood Bashash
- Department of Hematology and Blood Banking, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| |
Collapse
|
5
|
An Overview of Class II Phosphoinositide 3-Kinases. Curr Top Microbiol Immunol 2022; 436:51-68. [DOI: 10.1007/978-3-031-06566-8_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
6
|
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]
|
7
|
Mancia A, Abelli L, Fossi MC, Panti C. Skin distress associated with xenobiotics exposure: An epigenetic study in the Mediterranean fin whale (Balaenoptera physalus). Mar Genomics 2020; 57:100822. [PMID: 33069632 DOI: 10.1016/j.margen.2020.100822] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 09/14/2020] [Accepted: 10/05/2020] [Indexed: 12/21/2022]
Abstract
The phenotypic plasticity of many organisms is mediated in part by epigenetics, the heritable changes in gene activity that occur without any alterations to DNA sequence. A major mechanism in epigenetics is the DNA methylation (DNAm). Hypo- and hyper-methylation are generalized responses to control gene expression however recent studies have demonstrated that classes of contaminants could mark specific DNAm signatures, that could usefully signal prior environmental exposure. We collected skin and blubber from 6 free-ranging fin whale (Balaenoptera physalus) individuals sampled as a part of a previous published study in the northern Mediterranean Sea. Genomic DNA extracted from the skin of the fin whales and levels of contaminants measured in the blubber of the same individuals were used for DNAm profiling through reduced representation bisulfite sequencing (RRBS). We tested the hypothesis that differences in the methylation patterns could be related to environmental exposure to contaminants and load in the whale tissues. The aims of this study were to determine the DNAm profiles of the methylation contexts (CpGs and non-CpGs) of differently contaminated groups using the RRBS, and to identify potential contaminant exposure related genes. Amount and proportion of methylcytosines in CpG and non-CpG regions (CHH and CHG) was very similar across the 6 samples. The proportion of methylcytosines sites in CpG was n = 32,682, the highest among all the sequence contexts (n = 3216 in CHH; n = 1743 in CHG). The majority of the methylcytosine occurred in the intron regions, followed by exon and promoter regions in CpG, CHH and CHG. Gene Ontology results indicated that DNAm affected genes that take place in cell differentiation and function in cutaneous, vascular and nervous systems. The identification of cellular response pathways allows a better understanding of the organism biological reaction to a specific environmental challenge and the development of sensitive tools based on the predictive responses. Eco-epigenetics analyses have an extraordinary potential to address growing issues on pollution biomonitoring, ecotoxicity assessment, conservation and management planning.
Collapse
Affiliation(s)
- Annalaura Mancia
- Department of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy.
| | - Luigi Abelli
- Department of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy
| | - Maria Cristina Fossi
- Department of Physical Sciences, Earth and Environment, University of Siena, 53100 Siena, Italy
| | - Cristina Panti
- Department of Physical Sciences, Earth and Environment, University of Siena, 53100 Siena, Italy
| |
Collapse
|
8
|
p110δ PI3K as a therapeutic target of solid tumours. Clin Sci (Lond) 2020; 134:1377-1397. [DOI: 10.1042/cs20190772] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 05/21/2020] [Accepted: 06/01/2020] [Indexed: 12/12/2022]
Abstract
AbstractFrom the time of first characterization of PI3K as a heterodimer made up of a p110 catalytic subunit and a regulatory subunit, a wealth of evidence have placed the class IA PI3Ks at the forefront of drug development for the treatment of various diseases including cancer. The p110α isoform was quickly brought at the centre of attention in the field of cancer research by the discovery of cancer-specific gain-of-function mutations in PIK3CA gene in a range of human solid tumours. In contrast, p110δ PI3K was placed into the spotlight of immunity, inflammation and haematologic malignancies because of the preferential expression of this isoform in leucocytes and the rare mutations in PIK3CD gene. The last decade, however, several studies have provided evidence showing that the correlation between the PIK3CA mutations and the response to PI3K inhibition is less clear than originally considered, whereas concurrently an unexpected role of p110δ PI3K in solid tumours has being emerging. While PIK3CD is mostly non-mutated in cancer, the expression levels of p110δ protein seem to act as an intrinsic cancer-causing driver in various solid tumours including breast, prostate, colorectal and liver cancer, Merkel-Cell carcinoma, glioblastoma and neurobalstoma. Furthermore, p110δ selective inhibitors are being studied as potential single agent treatments or as combination partners in attempt to improve cancer immunotherapy, with both strategies to shown great promise for the treatment of several solid tumours. In this review, we discuss the evidence implicating the p110δ PI3K in human solid tumours, their impact on the current state of the field and the potential of using p110δ-selective inhibitors as monotherapy or combined therapy in different cancer contexts.
Collapse
|
9
|
Arafeh R, Samuels Y. PIK3CA in cancer: The past 30 years. Semin Cancer Biol 2019; 59:36-49. [DOI: 10.1016/j.semcancer.2019.02.002] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 01/08/2019] [Accepted: 02/07/2019] [Indexed: 02/07/2023]
|
10
|
Gulluni F, De Santis MC, Margaria JP, Martini M, Hirsch E. Class II PI3K Functions in Cell Biology and Disease. Trends Cell Biol 2019; 29:339-359. [DOI: 10.1016/j.tcb.2019.01.001] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 12/21/2018] [Accepted: 01/02/2019] [Indexed: 12/12/2022]
|
11
|
Margaria JP, Ratto E, Gozzelino L, Li H, Hirsch E. Class II PI3Ks at the Intersection between Signal Transduction and Membrane Trafficking. Biomolecules 2019; 9:E104. [PMID: 30884740 PMCID: PMC6468456 DOI: 10.3390/biom9030104] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 03/01/2019] [Accepted: 03/11/2019] [Indexed: 12/11/2022] Open
Abstract
Phosphorylation of inositol phospholipids by the family of phosphoinositide 3-kinases (PI3Ks) is crucial in controlling membrane lipid composition and regulating a wide range of intracellular processes, which include signal transduction and vesicular trafficking. In spite of the extensive knowledge on class I PI3Ks, recent advances in the study of the three class II PI3Ks (PIK3C2A, PIK3C2B and PIK3C2G) reveal their distinct and non-overlapping cellular roles and localizations. By finely tuning membrane lipid composition in time and space among different cellular compartments, this class of enzymes controls many cellular processes, such as proliferation, survival and migration. This review focuses on the recent developments regarding the coordination of membrane trafficking and intracellular signaling of class II PI3Ks through the confined phosphorylation of inositol phospholipids.
Collapse
Affiliation(s)
- Jean Piero Margaria
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Turin, 10126 Turin, Italy.
| | - Edoardo Ratto
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Turin, 10126 Turin, Italy.
| | - Luca Gozzelino
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Turin, 10126 Turin, Italy.
| | - Huayi Li
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Turin, 10126 Turin, Italy.
| | - Emilio Hirsch
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Turin, 10126 Turin, Italy.
| |
Collapse
|
12
|
Steklov M, Pandolfi S, Baietti MF, Batiuk A, Carai P, Najm P, Zhang M, Jang H, Renzi F, Cai Y, Abbasi Asbagh L, Pastor T, De Troyer M, Simicek M, Radaelli E, Brems H, Legius E, Tavernier J, Gevaert K, Impens F, Messiaen L, Nussinov R, Heymans S, Eyckerman S, Sablina AA. Mutations in LZTR1 drive human disease by dysregulating RAS ubiquitination. Science 2018; 362:1177-1182. [PMID: 30442762 PMCID: PMC8058620 DOI: 10.1126/science.aap7607] [Citation(s) in RCA: 122] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 05/31/2018] [Accepted: 10/30/2018] [Indexed: 12/15/2022]
Abstract
The leucine zipper-like transcriptional regulator 1 (LZTR1) protein, an adaptor for cullin 3 (CUL3) ubiquitin ligase complex, is implicated in human disease, yet its mechanism of action remains unknown. We found that Lztr1 haploinsufficiency in mice recapitulates Noonan syndrome phenotypes, whereas LZTR1 loss in Schwann cells drives dedifferentiation and proliferation. By trapping LZTR1 complexes from intact mammalian cells, we identified the guanosine triphosphatase RAS as a substrate for the LZTR1-CUL3 complex. Ubiquitome analysis showed that loss of Lztr1 abrogated Ras ubiquitination at lysine-170. LZTR1-mediated ubiquitination inhibited RAS signaling by attenuating its association with the membrane. Disease-associated LZTR1 mutations disrupted either LZTR1-CUL3 complex formation or its interaction with RAS proteins. RAS regulation by LZTR1-mediated ubiquitination provides an explanation for the role of LZTR1 in human disease.
Collapse
Affiliation(s)
- M Steklov
- VIB-KU Leuven Center for Cancer Biology, VIB, 3000 Leuven, Belgium
- Department of Oncology, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - S Pandolfi
- VIB-KU Leuven Center for Cancer Biology, VIB, 3000 Leuven, Belgium
- Department of Oncology, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - M F Baietti
- VIB-KU Leuven Center for Cancer Biology, VIB, 3000 Leuven, Belgium
- Department of Oncology, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - A Batiuk
- VIB-KU Leuven Center for Cancer Biology, VIB, 3000 Leuven, Belgium
- Department of Oncology, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - P Carai
- Department of Cardiovascular Sciences, Centre for Molecular and Vascular Biology, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - P Najm
- VIB-KU Leuven Center for Cancer Biology, VIB, 3000 Leuven, Belgium
- Department of Oncology, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - M Zhang
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, USA
| | - H Jang
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, USA
| | - F Renzi
- VIB-KU Leuven Center for Cancer Biology, VIB, 3000 Leuven, Belgium
- Department of Oncology, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Y Cai
- VIB-KU Leuven Center for Cancer Biology, VIB, 3000 Leuven, Belgium
- Department of Oncology, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - L Abbasi Asbagh
- VIB-KU Leuven Center for Cancer Biology, VIB, 3000 Leuven, Belgium
- Department of Oncology, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - T Pastor
- VIB-KU Leuven Center for Cancer Biology, VIB, 3000 Leuven, Belgium
- Department of Oncology, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - M De Troyer
- VIB-KU Leuven Center for Cancer Biology, VIB, 3000 Leuven, Belgium
- Department of Oncology, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - M Simicek
- VIB-KU Leuven Center for Cancer Biology, VIB, 3000 Leuven, Belgium
- Department of Oncology, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - E Radaelli
- Department of Human Genetics, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - H Brems
- Department of Human Genetics, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - E Legius
- Department of Human Genetics, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - J Tavernier
- VIB Medical Biotechnology Center, Albert Baertsoenkaai 3, 9000 Ghent, Belgium
- Department of Biochemistry, Ghent University, Albert Baertsoenkaai 3, 9000 Ghent, Belgium
| | - K Gevaert
- VIB Medical Biotechnology Center, Albert Baertsoenkaai 3, 9000 Ghent, Belgium
- Department of Biochemistry, Ghent University, Albert Baertsoenkaai 3, 9000 Ghent, Belgium
| | - F Impens
- VIB Proteomics Core, Albert Baertsoenkaai 3, 9000 Ghent, Belgium
| | - L Messiaen
- Department of Human Genetics, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
- Department of Genetics, University of Alabama, Birmingham, AL 35294, USA
| | - R Nussinov
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, USA
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - S Heymans
- Department of Cardiovascular Sciences, Centre for Molecular and Vascular Biology, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
- Department of Cardiology, CARIM School for Cardiovascular Diseases Faculty of Health, Medicine and Life Sciences, Maastricht University, Netherlands
- The Netherlands Heart Institute, Nl-HI, Utrecht, Netherlands
| | - S Eyckerman
- VIB Medical Biotechnology Center, Albert Baertsoenkaai 3, 9000 Ghent, Belgium
- Department of Biochemistry, Ghent University, Albert Baertsoenkaai 3, 9000 Ghent, Belgium
| | - A A Sablina
- VIB-KU Leuven Center for Cancer Biology, VIB, 3000 Leuven, Belgium.
- Department of Oncology, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| |
Collapse
|
13
|
Wang H, Lo WT, Vujičić Žagar A, Gulluni F, Lehmann M, Scapozza L, Haucke V, Vadas O. Autoregulation of Class II Alpha PI3K Activity by Its Lipid-Binding PX-C2 Domain Module. Mol Cell 2018; 71:343-351.e4. [DOI: 10.1016/j.molcel.2018.06.042] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 05/14/2018] [Accepted: 06/27/2018] [Indexed: 11/30/2022]
|
14
|
Kind M, Klukowska-Rötzler J, Berezowska S, Arcaro A, Charles RP. Questioning the role of selected somatic PIK3C2B mutations in squamous non-small cell lung cancer oncogenesis. PLoS One 2017; 12:e0187308. [PMID: 29088297 PMCID: PMC5663493 DOI: 10.1371/journal.pone.0187308] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2017] [Accepted: 10/17/2017] [Indexed: 12/11/2022] Open
Abstract
PI3K signaling is frequently dysregulated in NSCLC-SQCC. In contrast to well characterized components of the PI3K signaling network contributing to the formation of SQCC, potential oncogenic effects of alterations in PIK3C2B are poorly understood. Here, a large cohort (n = 362) of NSCLC-SQCC was selectively screened for four reported somatic mutations in PIK3C2B via Sanger sequencing. In addition, two mutations leading to an amino acid exchange in the kinase domain (C1181, H1208R) were examined on a functional level. None of the mutations were identified in the cohort while well characterized hotspot PIK3CA mutations were observed at the expected frequency. Ultimately, kinase domain mutations in PI3KC2β were found to have no altering effect on downstream signaling. A set of SQCC tumors sequenced by The Cancer Genome Atlas (TCGA) equally indicates a lack of oncogenic potential of the kinase domain mutations or PIK3C2B in general. Taken together, this study suggests that PIK3C2B might only have a minor role in SQCC oncogenesis.
Collapse
Affiliation(s)
- Marcus Kind
- University Children’s Hospital Bern, Freiburgstrasse 31, Bern, Switzerland
| | - Jolanta Klukowska-Rötzler
- University Children’s Hospital Bern, Freiburgstrasse 31, Bern, Switzerland
- Department of Emergency Medicine, University Hospital Bern, Freiburgstrasse 16c, Bern, Switzerland
| | - Sabina Berezowska
- Institute of Pathology, University of Bern, Murtenstrasse 31,Bern, Switzerland
| | - Alexandre Arcaro
- University Children’s Hospital Bern, Freiburgstrasse 31, Bern, Switzerland
| | - Roch-Philippe Charles
- Institute of Biochemistry and Molecular Medicine, and Swiss National Center of Competence in Research (NCCR) TransCure, University of Bern, Bühlstrasse 28, Bern, Switzerland
| |
Collapse
|
15
|
Lu L, Sha S, Wang K, Zhang YH, Liu YD, Ju GD, Wang B, Zhu HL. Discovery of Chromeno[4,3-c]pyrazol-4(2H)-one Containing Carbonyl or Oxime Derivatives as Potential, Selective Inhibitors PI3Kα. Chem Pharm Bull (Tokyo) 2016; 64:1576-1581. [PMID: 27581755 DOI: 10.1248/cpb.c16-00388] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A series of novel chromeno[4,3-c]pyrazol-4(2H)-one containing carbonyl or oxime derivatives (4a-n, 5a-n) have been synthesized and evaluated their biological activities as phosphatidyl inositol 3-kinase (PI3K) inhibitors. Out of them, compound 5l showed the most potent antiproliferative activities against HCT-116 with IC50 of 0.10 µM in vitro, and exhibited the most potent activity for PI3Kα with the value of 0.012 µM. Docking simulation of 5l into PI3Kα active site were performed to determine the probable binding model, and it indicated that compound 5l could be optimized as a potential inhibitor of PI3Kα in the further study.
Collapse
Affiliation(s)
- Liang Lu
- State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University
| | | | | | | | | | | | | | | |
Collapse
|
16
|
Yan X, Xia ZQ, Shen H, Traynor-Kaplan A. External Qi of Yan Xin Life Science Technology Can Revive or Suppress Enzyme Activity of Phosphatidylinositol 3-Kinase. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/027046702237270] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Phosphatidylinositol 3 kinase (PI 3-kinase) is an important enzyme that is involved in the regulation of a variety of biological processes such as apoptosis, cell division, and ion channel activity and can play a role in the pathological development of a number of diseases, including AIDS and cancer. The authors’ data indicate that external qi of Yan Xin Life Science Technology (YXLST) can modulate enzyme activity in two directions. Within a time window of 3 days of the initial emission of external qi of YXLST, PI 3-kinase activity was restored in an outdated enzyme sample that had lost activity, and PI 3-kinase activity was suppressed in a freshly purified sample relative to an untreated control sample so that its activity was nearly undetectable. The data presented are consistent with the hypothesis that external qi of YXLST can alter molecular events. The uniqueness of this and other observations mandates further study.
Collapse
Affiliation(s)
- Xin Yan
- Chongqing Institute of Traditional Chinese Medicine/New Medicine Science Research Institute
| | - Zhen-Qin Xia
- School of Medicine, University of California at San Diego
| | - Hua Shen
- New Medicine Science Research Institute
| | | |
Collapse
|
17
|
Novel roles for class II Phosphoinositide 3-Kinase C2β in signalling pathways involved in prostate cancer cell invasion. Sci Rep 2016; 6:23277. [PMID: 26983806 PMCID: PMC4794650 DOI: 10.1038/srep23277] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 03/03/2016] [Indexed: 12/14/2022] Open
Abstract
Phosphoinositide 3-kinases (PI3Ks) regulate several cellular functions such as proliferation, growth, survival and migration. The eight PI3K isoforms are grouped into three classes and the three enzymes belonging to the class II subfamily (PI3K-C2α, β and γ) are the least investigated amongst all PI3Ks. Interest on these isoforms has been recently fuelled by the identification of specific physiological roles for class II PI3Ks and by accumulating evidence indicating their involvement in human diseases. While it is now established that these isoforms can regulate distinct cellular functions compared to other PI3Ks, there is still a limited understanding of the signalling pathways that can be specifically regulated by class II PI3Ks. Here we show that PI3K-C2β regulates mitogen-activated protein kinase kinase (MEK1/2) and extracellular signal-regulated kinase (ERK1/2) activation in prostate cancer (PCa) cells. We further demonstrate that MEK/ERK and PI3K-C2β are required for PCa cell invasion but not proliferation. In addition we show that PI3K-C2β but not MEK/ERK regulates PCa cell migration as well as expression of the transcription factor Slug. These data identify novel signalling pathways specifically regulated by PI3K-C2β and they further identify this enzyme as a key regulator of PCa cell migration and invasion.
Collapse
|
18
|
Imbalanced insulin action in chronic over nutrition: Clinical harm, molecular mechanisms, and a way forward. Atherosclerosis 2016; 247:225-82. [PMID: 26967715 DOI: 10.1016/j.atherosclerosis.2016.02.004] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 12/31/2015] [Accepted: 02/02/2016] [Indexed: 02/08/2023]
Abstract
The growing worldwide prevalence of overnutrition and underexertion threatens the gains that we have made against atherosclerotic cardiovascular disease and other maladies. Chronic overnutrition causes the atherometabolic syndrome, which is a cluster of seemingly unrelated health problems characterized by increased abdominal girth and body-mass index, high fasting and postprandial concentrations of cholesterol- and triglyceride-rich apoB-lipoproteins (C-TRLs), low plasma HDL levels, impaired regulation of plasma glucose concentrations, hypertension, and a significant risk of developing overt type 2 diabetes mellitus (T2DM). In addition, individuals with this syndrome exhibit fatty liver, hypercoagulability, sympathetic overactivity, a gradually rising set-point for body adiposity, a substantially increased risk of atherosclerotic cardiovascular morbidity and mortality, and--crucially--hyperinsulinemia. Many lines of evidence indicate that each component of the atherometabolic syndrome arises, or is worsened by, pathway-selective insulin resistance and responsiveness (SEIRR). Individuals with SEIRR require compensatory hyperinsulinemia to control plasma glucose levels. The result is overdrive of those pathways that remain insulin-responsive, particularly ERK activation and hepatic de-novo lipogenesis (DNL), while carbohydrate regulation deteriorates. The effects are easily summarized: if hyperinsulinemia does something bad in a tissue or organ, that effect remains responsive in the atherometabolic syndrome and T2DM; and if hyperinsulinemia might do something good, that effect becomes resistant. It is a deadly imbalance in insulin action. From the standpoint of human health, it is the worst possible combination of effects. In this review, we discuss the origins of the atherometabolic syndrome in our historically unprecedented environment that only recently has become full of poorly satiating calories and incessant enticements to sit. Data are examined that indicate the magnitude of daily caloric imbalance that causes obesity. We also cover key aspects of healthy, balanced insulin action in liver, endothelium, brain, and elsewhere. Recent insights into the molecular basis and pathophysiologic harm from SEIRR in these organs are discussed. Importantly, a newly discovered oxide transport chain functions as the master regulator of the balance amongst different limbs of the insulin signaling cascade. This oxide transport chain--abbreviated 'NSAPP' after its five major proteins--fails to function properly during chronic overnutrition, resulting in this harmful pattern of SEIRR. We also review the origins of widespread, chronic overnutrition. Despite its apparent complexity, one factor stands out. A sophisticated junk food industry, aided by subsidies from willing governments, has devoted years of careful effort to promote overeating through the creation of a new class of food and drink that is low- or no-cost to the consumer, convenient, savory, calorically dense, yet weakly satiating. It is past time for the rest of us to overcome these foes of good health and solve this man-made epidemic.
Collapse
|
19
|
Kitatani K, Usui T, Sriraman SK, Toyoshima M, Ishibashi M, Shigeta S, Nagase S, Sakamoto M, Ogiso H, Okazaki T, Hannun YA, Torchilin VP, Yaegashi N. Ceramide limits phosphatidylinositol-3-kinase C2β-controlled cell motility in ovarian cancer: potential of ceramide as a metastasis-suppressor lipid. Oncogene 2015; 35:2801-12. [PMID: 26364609 PMCID: PMC4791218 DOI: 10.1038/onc.2015.330] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Revised: 06/19/2015] [Accepted: 07/17/2015] [Indexed: 12/15/2022]
Abstract
Targeting cell motility, which is required for dissemination and metastasis, has therapeutic potential for ovarian cancer metastasis, and regulatory mechanisms of cell motility need to be uncovered for developing novel therapeutics. Invasive ovarian cancer cells spontaneously formed protrusions, such as lamellipodia, which are required for generating locomotive force in cell motility. Short interfering RNA screening identified class II phosphatidylinositol 3-kinase C2β (PI3KC2β) as the predominant isoform of PI3K involved in lamellipodia formation of ovarian cancer cells. The bioactive sphingolipid ceramide has emerged as an antitumorigenic lipid, and treatment with short-chain C6-ceramide decreased the number of ovarian cancer cells with PI3KC2β-driven lamellipodia. Pharmacological analysis demonstrated that long-chain ceramide regenerated from C6-ceramide through the salvage/recycling pathway, at least in part, mediated the action of C6-ceramide. Mechanistically, ceramide was revealed to interact with the PIK-catalytic domain of PI3KC2β and affect its compartmentalization, thereby suppressing PI3KC2β activation and its driven cell motility. Ceramide treatment also suppressed cell motility promoted by epithelial growth factor, which is a prometastatic factor. To examine the role of ceramide in ovarian cancer metastasis, ceramide liposomes were employed and confirmed to suppress cell motility in vitro. Ceramide liposomes had an inhibitory effect on peritoneal metastasis in a murine xenograft model of human ovarian cancer. Metastasis of PI3KC2β knocked-down cells was insensitive to treatment with ceramide liposomes, suggesting specific involvement of ceramide interaction with PI3KC2β in metastasis suppression. Our study identified ceramide as a bioactive lipid that limits PI3KC2β-governed cell motility, and ceramide is proposed to serve as a metastasis-suppressor lipid in ovarian cancer. These findings could be translated into developing ceramide-based therapy for metastatic diseases.
Collapse
Affiliation(s)
- K Kitatani
- Tohoku Medical Megabank Organization, Tohoku University Graduate School of Medicine, Tohoku University, Sendai, Japan.,Department of Obstetrics and Gynecology, Tohoku University Graduate School of Medicine, Tohoku University, Sendai, Japan
| | - T Usui
- Tohoku Medical Megabank Organization, Tohoku University Graduate School of Medicine, Tohoku University, Sendai, Japan
| | - S K Sriraman
- Department of Pharmaceutical Sciences, Center for Pharmaceutical Biotechnology and Nanomedicine, Northeastern University, Boston, MA, USA
| | - M Toyoshima
- Department of Obstetrics and Gynecology, Tohoku University Graduate School of Medicine, Tohoku University, Sendai, Japan
| | - M Ishibashi
- Department of Obstetrics and Gynecology, Tohoku University Graduate School of Medicine, Tohoku University, Sendai, Japan
| | - S Shigeta
- Department of Obstetrics and Gynecology, Tohoku University Graduate School of Medicine, Tohoku University, Sendai, Japan
| | - S Nagase
- Department of Obstetrics and Gynecology, Yamagata University, Yamagata, Japan
| | - M Sakamoto
- Department of Obstetrics and Gynecology, Tohoku University Graduate School of Medicine, Tohoku University, Sendai, Japan
| | - H Ogiso
- Department of Life Science, Medical Research Institute, Kanazawa Medical University, Ishikawa, Japan
| | - T Okazaki
- Department of Life Science, Medical Research Institute, Kanazawa Medical University, Ishikawa, Japan.,Department of Medicine, Division of Hematology/Immunology, Kanazawa Medical University, Ishikawa, Japan
| | - Y A Hannun
- Stony Brook Cancer Center and Department of Medicine, Stony Brook University, Stony Brook, NY, USA
| | - V P Torchilin
- Department of Pharmaceutical Sciences, Center for Pharmaceutical Biotechnology and Nanomedicine, Northeastern University, Boston, MA, USA
| | - N Yaegashi
- Tohoku Medical Megabank Organization, Tohoku University Graduate School of Medicine, Tohoku University, Sendai, Japan.,Department of Obstetrics and Gynecology, Tohoku University Graduate School of Medicine, Tohoku University, Sendai, Japan
| |
Collapse
|
20
|
Yagi H, Conroy PJ, Leung EWW, Law RHP, Trapani JA, Voskoboinik I, Whisstock JC, Norton RS. Structural Basis for Ca2+-mediated Interaction of the Perforin C2 Domain with Lipid Membranes. J Biol Chem 2015; 290:25213-26. [PMID: 26306037 DOI: 10.1074/jbc.m115.668384] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Indexed: 11/06/2022] Open
Abstract
Natural killer cells and cytotoxic T-lymphocytes deploy perforin and granzymes to kill infected host cells. Perforin, secreted by immune cells, binds target membranes to form pores that deliver pro-apoptotic granzymes into the target cell. A crucial first step in this process is interaction of its C2 domain with target cell membranes, which is a calcium-dependent event. Some aspects of this process are understood, but many molecular details remain unclear. To address this, we investigated the mechanism of Ca(2+) and lipid binding to the C2 domain by NMR spectroscopy and x-ray crystallography. Calcium titrations, together with dodecylphosphocholine micelle experiments, confirmed that multiple Ca(2+) ions bind within the calcium-binding regions, activating perforin with respect to membrane binding. We have also determined the affinities of several of these binding sites and have shown that this interaction causes a significant structural rearrangement in CBR1. Thus, it is proposed that Ca(2+) binding at the weakest affinity site triggers changes in the C2 domain that facilitate its interaction with lipid membranes.
Collapse
Affiliation(s)
- Hiromasa Yagi
- From the Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052
| | - Paul J Conroy
- the Department of Biochemistry and Molecular Biology and ARC Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800
| | - Eleanor W W Leung
- From the Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052
| | - Ruby H P Law
- the Department of Biochemistry and Molecular Biology and ARC Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800
| | - Joseph A Trapani
- the Cancer Immunology Program, Peter MacCallum Cancer Centre, East Melbourne, Victoria 3002, and the Departments of Microbiology and Immunology and
| | - Ilia Voskoboinik
- the Cancer Immunology Program, Peter MacCallum Cancer Centre, East Melbourne, Victoria 3002, and the Departments of Microbiology and Immunology and Genetics and Pathology, University of Melbourne, Parkville, Victoria 3052, Australia
| | - James C Whisstock
- the Department of Biochemistry and Molecular Biology and ARC Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800,
| | - Raymond S Norton
- From the Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052,
| |
Collapse
|
21
|
New insight into the intracellular roles of class II phosphoinositide 3-kinases. Biochem Soc Trans 2015; 42:1378-82. [PMID: 25233418 DOI: 10.1042/bst20140140] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
In the last few years, an increased attention to class II isoforms of phosphoinositide 3-kinase (PI3K) has emerged, mainly fuelled by evidence suggesting a distinct non-redundant role for these enzymes compared with other PI3Ks. Despite this renewed interest, many questions remain on the specific functions regulated by these isoforms and their mechanism of activation and action. In the present review, we discuss results from recent studies that have provided some answers to these questions.
Collapse
|
22
|
Davis WJ, Lehmann PZ, Li W. Nuclear PI3K signaling in cell growth and tumorigenesis. Front Cell Dev Biol 2015; 3:24. [PMID: 25918701 PMCID: PMC4394695 DOI: 10.3389/fcell.2015.00024] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Accepted: 03/27/2015] [Indexed: 12/12/2022] Open
Abstract
The PI3K/Akt signaling pathway is a major driving force in a variety of cellular functions. Dysregulation of this pathway has been implicated in many human diseases including cancer. While the activity of the cytoplasmic PI3K/Akt pathway has been extensively studied, the functions of these molecules and their effector proteins within the nucleus are poorly understood. Harboring key cellular processes such as DNA replication and repair as well as nascent messenger RNA transcription, the nucleus provides a unique compartmental environment for protein–protein and protein–DNA/RNA interactions required for cell survival, growth, and proliferation. Here we summarize recent advances made toward elucidating the nuclear PI3K/Akt signaling cascade and its key components within the nucleus as they pertain to cell growth and tumorigenesis. This review covers the spatial and temporal localization of the major nuclear kinases having PI3K activities and the counteracting phosphatases as well as the role of nuclear PI3K/Akt signaling in mRNA processing and exportation, DNA replication and repair, ribosome biogenesis, cell survival, and tumorigenesis.
Collapse
Affiliation(s)
- William J Davis
- College of Medical Sciences, Washington State University Spokane, WA, USA
| | - Peter Z Lehmann
- College of Medical Sciences, Washington State University Spokane, WA, USA
| | - Weimin Li
- College of Medical Sciences, Washington State University Spokane, WA, USA
| |
Collapse
|
23
|
Nigorikawa K, Hazeki K, Guo Y, Hazeki O. Involvement of class II phosphoinositide 3-kinase α-isoform in antigen-induced degranulation in RBL-2H3 cells. PLoS One 2014; 9:e111698. [PMID: 25357130 PMCID: PMC4214793 DOI: 10.1371/journal.pone.0111698] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 10/07/2014] [Indexed: 12/13/2022] Open
Abstract
In this study, we present findings that suggest that PI3K-C2α, a member of the class II phosphoinositide 3-kinase (PI3K) subfamily, regulates the process of FcεRI-triggered degranulation. RBL-2H3 cells were transfected with shRNA targeting PI3K-C2α. The knockdown impaired the FcεRI-induced release of a lysosome enzyme, β-hexosaminidase, without affecting the intracellular Ca2+ mobilization. The release of mRFP-tagged neuropeptide-Y, a reporter for the regulated exocytosis, was also decreased in the PI3K-C2α-deficient cells. The release was increased significantly by the expression of the siRNA-resistant version of PI3K-C2α. In wild-type cells, FcεRI stimulation induced the formation of large vesicles, which were associated with CD63, a marker protein of secretory granules. On the vesicles, the existence of PI3K-C2α and PtdIns(3,4)P2 was observed. These results indicated that PI3K-C2α and its product PtdIns(3,4)P2 may play roles in the secretory process.
Collapse
Affiliation(s)
- Kiyomi Nigorikawa
- Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan
- * E-mail:
| | - Kaoru Hazeki
- Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Ying Guo
- Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Osamu Hazeki
- Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan
| |
Collapse
|
24
|
Assessing the subcellular distribution of oncogenic phosphoinositide 3-kinase using microinjection into live cells. Biosci Rep 2014; 34:BSR20130133. [PMID: 27919038 PMCID: PMC3985441 DOI: 10.1042/bsr20130133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 02/18/2014] [Accepted: 03/04/2014] [Indexed: 02/07/2023] Open
Abstract
Oncogenic mutations in PIK3CA lead to an increase in intrinsic phosphoinositide kinase activity, but it is thought that increased access of PI3Kα (phosphoinositide 3-kinase α) to its PM (plasma membrane) localized substrate is also required for increased levels of downstream PIP3/Akt [phosphoinositide-3,4,5-trisphosphate/also called PKB (protein kinase B)] signalling. We have studied the subcellular localization of wild-type and the two most common oncogenic mutants of PI3Kα in cells maintained in growth media, and starved or stimulated cells using a novel method in which PI3Kα is pre-formed as a 1:1 p110α:p85α complex in vitro then introduced into live cells by microinjection. Oncogenic E545K and H1047R mutants did not constitutively interact with membrane lipids in vitro or in cells maintained in 10% (v/v) FBS. Following stimulation of RTKs (receptor tyrosine kinases), microinjected PI3Kα was recruited to the PM, but oncogenic forms of PI3Kα were not recruited to the PM to a greater extent and did not reside at the PM longer than the wild-type PI3Kα. Instead, the E545K mutant specifically bound activated Cdc42 in vitro and microinjection of E545K was associated with the formation of cellular protrusions, providing some preliminary evidence that changes in protein–protein interactions may play a role in the oncogenicity of the E545K mutant in addition to the well-known changes in lipid kinase activity. Oncogenic forms of PI3Kα (phosphoinositide 3-kinase α) microinjected into live cells are not recruited to the PM (plasma membrane) to a greater extent, and do not reside at the PM longer, than wild-type PI3Kα.
Collapse
|
25
|
Abstract
Phosphoinositide-3-kinase (PI3K) signaling has been implicated in a panoply of cellular responses including survival, proliferation, protein synthesis, migration, and vesicular trafficking. In addition, alterations in the enzymatic activity of PI3Ks have been involved in the pathogenesis of multiple diseases, ranging from cancer to chronic inflammation. The emerging interest in PI3K as a pharmacological target has prompted the development of several molecules with inhibitory activity. In this context, the quantification of the second messenger generated by PI3Ks, phosphoinositide-3-phosphate, offers an opportunity to directly test variations in the lipid kinase activity of PI3K in physiological as well as pathological conditions. Here, we will describe common methods to measure the lipid kinase activity of PI3K in vitro and new techniques to follow the production of phosphoinositide-3-phosphate in vivo. These methods are relevant to study the alterations of the PI3K systems at the interface between signaling and oncometabolism.
Collapse
|
26
|
Akinleye A, Avvaru P, Furqan M, Song Y, Liu D. Phosphatidylinositol 3-kinase (PI3K) inhibitors as cancer therapeutics. J Hematol Oncol 2013; 6:88. [PMID: 24261963 PMCID: PMC3843585 DOI: 10.1186/1756-8722-6-88] [Citation(s) in RCA: 171] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 11/12/2013] [Indexed: 02/08/2023] Open
Abstract
Phosphatidylinositol 3-kinases (PI3Ks) are lipid kinases that regulate diverse cellular processes including proliferation, adhesion, survival, and motility. Dysregulated PI3K pathway signaling occurs in one-third of human tumors. Aberrantly activated PI3K signaling also confers sensitivity and resistance to conventional therapies. PI3K has been recognized as an attractive molecular target for novel anti-cancer molecules. In the last few years, several classes of potent and selective small molecule PI3K inhibitors have been developed, and at least fifteen compounds have progressed into clinical trials as new anticancer drugs. Among these, idelalisib has advanced to phase III trials in patients with advanced indolent non-Hodgkin's lymphoma and mantle cell lymphoma. In this review, we summarized the major molecules of PI3K signaling pathway, and discussed the preclinical models and clinical trials of potent small-molecule PI3K inhibitors.
Collapse
Affiliation(s)
| | | | | | | | - Delong Liu
- Division of Hematology/Oncology, Department of Medicine, New York Medical College and Westchester Medical Center, Valhalla, NY 10595, USA.
| |
Collapse
|
27
|
PtdIns(4)P signalling and recognition systems. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 991:59-83. [PMID: 23775691 DOI: 10.1007/978-94-007-6331-9_5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The Golgi apparatus is a sorting platform that exchanges extensively with the endoplasmic reticulum (ER), endosomes (Es) and plasma membrane (PM) compartments. The last compartment of the Golgi, the trans-Golgi Network (TGN) is a large complex of highly deformed membranes from which vesicles depart to their targeted organelles but also are harbored from retrograde pathways. The phosphoinositide (PI) composition of the TGN is marked by an important contingent of phosphatidylinositol-4-phosphate (PtdIns(4)P). Although this PI is present throughout the Golgi, its proportion grows along the successive cisternae and peaks at the TGN. The levels of this phospholipid are controlled by a set of kinases and phosphatases that regulate its concentrations in the Golgi and maintain a dynamic gradient that determines the cellular localization of several interacting proteins. Though not exclusive to the Golgi, the synthesis of PtdIns(4)P in other membranes is relatively marginal and has unclear consequences. The significance of PtdIns(4)P within the TGN has been demonstrated for numerous cellular events such as vesicle formation, lipid metabolism, and membrane trafficking.
Collapse
|
28
|
Giudice FS, Squarize CH. The determinants of head and neck cancer: Unmasking the PI3K pathway mutations. ACTA ACUST UNITED AC 2013; Suppl 5. [PMID: 25126449 DOI: 10.4172/2157-2518.s5-003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Studies attempting to identify and understand the function of mutated genes and deregulated molecular pathways in cancer have been ongoing for many years. The PI3K-PTEN-mTOR signaling pathway is one of the most frequently deregulated pathways in cancer. PIK3CA mutations are found 11%-33% of head and neck cancer (HNC). The hotspot mutation sites for PIK3CA are E542K, E545K and H1047R/L. The PTEN somatic mutations are in 9-23% of HNC, and they frequently cluster in the phosphatase domain of PTEN protein. PTEN loss of heterozygosity (LOH) ranges from 41%-71% and loss of PTEN protein expression occurs in 31.2% of the HNC samples. PIK3CA and PTEN are key molecules in the PI3K-PTEN-mTOR signaling pathway. In this review, we provided a comprehensive overview of mutations in the PI3K-PTEN-mTOR molecular circuitry in HNC, including PI3K family members, TSC1/TSC2, PTEN, AKT, and mTORC1 and mTORC2 complexes. We discussed how these genetic alterations may affect protein structure and function. We also highlight the latest discoveries in protein kinase and tumor suppressor families, emphasizing how mutations in these families interfere with PI3K signaling. A better understanding of the mechanisms underlying cancer formation, progression and resistance to therapy will inform selection of novel genomic-based personalized therapies for head and neck cancer patients.
Collapse
Affiliation(s)
- Fernanda S Giudice
- Laboratory of Epithelial Biology, Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, Michigan, 48109-1078, USA ; International Research Center, A. C. Camargo Cancer Center, São Paulo, SP, Brazil
| | - Cristiane H Squarize
- Laboratory of Epithelial Biology, Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, Michigan, 48109-1078, USA
| |
Collapse
|
29
|
Layton MJ, Saad M, Church NL, Pearson RB, Mitchell CA, Phillips WA. Autophosphorylation of serine 608 in the p85 regulatory subunit of wild type or cancer-associated mutants of phosphoinositide 3-kinase does not affect its lipid kinase activity. BMC BIOCHEMISTRY 2012; 13:30. [PMID: 23270540 PMCID: PMC3546864 DOI: 10.1186/1471-2091-13-30] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2012] [Accepted: 12/22/2012] [Indexed: 02/08/2023]
Abstract
Background The α-isoform of the Type 1A Phosphoinositide 3-kinases (PI3Kα) has protein kinase activity as well as phosphoinositide lipid kinase activity. The best described substrate for its protein kinase activity is its regulatory subunit, p85α, which becomes phosphorylated on Serine 608. Phosphorylation of Serine 608 has been reported to down-regulate its lipid kinase activity. Results We have assessed whether oncogenic mutants of PI3Kα, which have up-regulated lipid kinase activity, have altered levels of Serine 608 phosphorylation compared to wild type PI3Kα, and whether differential phosphorylation of Serine 608 contributes to increased activity of oncogenic forms of PI3Kα with point mutations in the helical or the kinase domains. Despite markedly increased lipid kinase activity, protein kinase activity was not altered in oncogenic compared to wild type forms of PI3Kα. By manipulating levels of phosphorylation of Serine 608 in vitro, we found no evidence that the protein kinase activity of PI3Kα affects its phosphoinositide lipid kinase activity in either wild-type or oncogenic mutants of PI3Kα. Conclusions Phosphorylation of p85α S608 is not a significant regulator of wild-type or oncogenic PI3Kα lipid kinase activity.
Collapse
Affiliation(s)
- Meredith J Layton
- The Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | | | | | | | | | | |
Collapse
|
30
|
Wong KA, Russo A, Wang X, Chen YJ, Lavie A, O'Bryan JP. A new dimension to Ras function: a novel role for nucleotide-free Ras in Class II phosphatidylinositol 3-kinase beta (PI3KC2β) regulation. PLoS One 2012; 7:e45360. [PMID: 23028960 PMCID: PMC3441633 DOI: 10.1371/journal.pone.0045360] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 08/14/2012] [Indexed: 12/31/2022] Open
Abstract
The intersectin 1 (ITSN1) scaffold stimulates Ras activation on endocytic vesicles without activating classic Ras effectors. The identification of Class II phosphatidylinositol 3-kinase beta, PI3KC2β, as an ITSN1 target on vesicles and the presence of a Ras binding domain (RBD) in PI3KC2β suggests a role for Ras in PI3KC2β activation. Here, we demonstrate that nucleotide-free Ras negatively regulates PI3KC2β activity. PI3KC2β preferentially interacts in vivo with dominant-negative (DN) Ras, which possesses a low affinity for nucleotides. PI3KC2β interaction with DN Ras is disrupted by switch 1 domain mutations in Ras as well as RBD mutations in PI3KC2β. Using purified proteins, we demonstrate that the PI3KC2β-RBD directly binds nucleotide-free Ras in vitro and that this interaction is not disrupted by nucleotide addition. Finally, nucleotide-free Ras but not GTP-loaded Ras inhibits PI3KC2β lipid kinase activity in vitro. Our findings indicate that PI3KC2β interacts with and is regulated by nucleotide-free Ras. These data suggest a novel role for nucleotide-free Ras in cell signaling in which PI3KC2β stabilizes nucleotide-free Ras and that interaction of Ras and PI3KC2β mutually inhibit one another.
Collapse
Affiliation(s)
- Katy A. Wong
- Department of Pharmacology, University of Illinois College of Medicine, Chicago, Illinois, United States of America
| | - Angela Russo
- Department of Pharmacology, University of Illinois College of Medicine, Chicago, Illinois, United States of America
| | - Xuerong Wang
- Department of Pharmacology, University of Illinois College of Medicine, Chicago, Illinois, United States of America
| | - Yun-Ju Chen
- Department of Pharmacology, University of Illinois College of Medicine, Chicago, Illinois, United States of America
| | - Arnon Lavie
- Cancer Center, University of Illinois College of Medicine, Chicago, Illinois, United States of America
- Biochemistry and Molecular Genetics, University of Illinois College of Medicine, Chicago, Illinois, United States of America
| | - John P. O'Bryan
- Department of Pharmacology, University of Illinois College of Medicine, Chicago, Illinois, United States of America
- Cancer Center, University of Illinois College of Medicine, Chicago, Illinois, United States of America
- Center for Cardiovascular Research, University of Illinois College of Medicine, Chicago, Illinois, United States of America
| |
Collapse
|
31
|
Błajecka K, Marinov M, Leitner L, Uth K, Posern G, Arcaro A. Phosphoinositide 3-kinase C2β regulates RhoA and the actin cytoskeleton through an interaction with Dbl. PLoS One 2012; 7:e44945. [PMID: 22984590 PMCID: PMC3440356 DOI: 10.1371/journal.pone.0044945] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Accepted: 08/14/2012] [Indexed: 12/31/2022] Open
Abstract
The regulation of cell morphology is a dynamic process under the control of multiple protein complexes acting in a coordinated manner. Phosphoinositide 3-kinases (PI3K) and their lipid products are widely involved in cytoskeletal regulation by interacting with proteins regulating RhoGTPases. Class II PI3K isoforms have been implicated in the regulation of the actin cytoskeleton, although their exact role and mechanism of action remain to be established. In this report, we have identified Dbl, a Rho family guanine nucleotide exchange factor (RhoGEF) as an interaction partner of PI3KC2β. Dbl was co-immunoprecipitated with PI3KC2β in NIH3T3 cells and cancer cell lines. Over-expression of Class II phosphoinositide 3-kinase PI3KC2β in NIH3T3 fibroblasts led to increased stress fibres formation and cell spreading. Accordingly, we found high basal RhoA activity and increased serum response factor (SRF) activation downstream of RhoA upon serum stimulation. In contrast, the dominant-negative form of PI3KC2β strongly reduced cell spreading and stress fibres formation, as well as SRF response. Platelet-derived growth factor (PDGF) stimulation of wild-type PI3KC2β over-expressing NIH3T3 cells strongly increased Rac and c-Jun N-terminal kinase (JNK) activation, but failed to show similar effect in the cells with the dominant-negative enzyme. Interestingly, epidermal growth factor (EGF) and PDGF stimulation led to increased extracellular signal-regulated kinase (Erk) and Akt pathway activation in cells with elevated wild-type PI3KC2β expression. Furthermore, increased expression of PI3KC2β protected NIH3T3 from detachment-dependent death (anoikis) in a RhoA-dependent manner. Taken together, these findings suggest that PI3KC2β modulates the cell morphology and survival through a specific interaction with Dbl and the activation of RhoA.
Collapse
Affiliation(s)
- Karolina Błajecka
- Department of Clinical Research, University of Bern, Bern, Switzerland
| | - Marin Marinov
- Department of Oncology, University Children’s Hospital Zurich, Zurich, Switzerland
| | - Laura Leitner
- Department of Molecular Biology, AG Regulation of Gene Expression, Max-Planck-Institute of Biochemistry, Martinsried, Germany
| | - Kristin Uth
- Department of Clinical Research, University of Bern, Bern, Switzerland
| | - Guido Posern
- Department of Molecular Biology, AG Regulation of Gene Expression, Max-Planck-Institute of Biochemistry, Martinsried, Germany
| | - Alexandre Arcaro
- Department of Clinical Research, University of Bern, Bern, Switzerland
- * E-mail:
| |
Collapse
|
32
|
Braccini L, Ciraolo E, Martini M, Pirali T, Germena G, Rolfo K, Hirsch E. PI3K keeps the balance between metabolism and cancer. Adv Biol Regul 2012; 52:389-405. [PMID: 22884032 DOI: 10.1016/j.jbior.2012.04.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Accepted: 04/11/2012] [Indexed: 06/01/2023]
Abstract
Epidemiological studies have established a positive correlation between cancer and metabolic disorders, suggesting that aberrant cell metabolism is a common feature of nearly all tumors. To meet their demand of building block molecules, cancer cells switch to a heavily glucose-dependent metabolism. As insulin triggers glucose uptake, most tumors are or become insulin-dependent. However, the effects of insulin and of other similar growth factors are not only limited to metabolic control but also favor tumor growth by stimulating proliferation and survival. A key signaling event mediating these metabolic and proliferative responses is the activation of the phosphatidylinositol-3 kinases (PI3K) pathway. In this review, we will thus discuss the current concepts of tumor metabolism and the opportunity of PI3K-targeted therapies to exploit the "sweet tooth" of cancer cells.
Collapse
Affiliation(s)
- L Braccini
- Department of Genetics, Biology and Biochemistry, Molecular Biotechnology Center, University of Torino, Torino, Italy
| | | | | | | | | | | | | |
Collapse
|
33
|
Falasca M, Maffucci T. Regulation and cellular functions of class II phosphoinositide 3-kinases. Biochem J 2012; 443:587-601. [PMID: 22507127 DOI: 10.1042/bj20120008] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Class II isoforms of PI3K (phosphoinositide 3-kinase) are still the least investigated and characterized of all PI3Ks. In the last few years, an increased interest in these enzymes has improved our understanding of their cellular functions. However, several questions still remain unanswered on their mechanisms of activation, their specific downstream effectors and their contribution to physiological processes and pathological conditions. Emerging evidence suggests that distinct PI3Ks activate different signalling pathways, indicating that their functional roles are probably not redundant. In the present review, we discuss the recent advances in our understanding of mammalian class II PI3Ks and the evidence suggesting their involvement in human diseases.
Collapse
Affiliation(s)
- Marco Falasca
- Inositide Signalling Group, Centre for Diabetes, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, 4 Newark Street, London E1 2AT, UK.
| | | |
Collapse
|
34
|
Abstract
Over the past two decades, our understanding of phospoinositide 3-kinases (PI3Ks) has progressed from the identification of an enzymatic activity associated with growth factors, GPCRs and certain oncogene products to a disease target in cancer and inflammation, with PI3K inhibitors currently in clinical trials. Elucidation of PI3K-dependent networks led to the discovery of the phosphoinositide-binding PH, PX and FYVE domains as conduits of intracellular lipid signalling, the determination of the molecular function of the tumour suppressor PTEN and the identification of AKT and mTOR protein kinases as key regulators of cell growth. Here we look back at the main discoveries that shaped the PI3K field.
Collapse
|
35
|
Lu N, Shen Q, Mahoney TR, Neukomm LJ, Wang Y, Zhou Z. Two PI 3-kinases and one PI 3-phosphatase together establish the cyclic waves of phagosomal PtdIns(3)P critical for the degradation of apoptotic cells. PLoS Biol 2012; 10:e1001245. [PMID: 22272187 PMCID: PMC3260314 DOI: 10.1371/journal.pbio.1001245] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Accepted: 12/05/2011] [Indexed: 11/24/2022] Open
Abstract
Cyclic oscillations in the level of phosphatidylinositol 3-phosphate in phagosomes, regulated by two phosphoinositide kinases and one phosphatase, are critical for phagosome maturation and degradation of apoptotic cells. Phosphatidylinositol 3-phosphate (PtdIns(3)P) is a signaling molecule important for many membrane trafficking events, including phagosome maturation. The level of PtdIns(3)P on phagosomes oscillates in two waves during phagosome maturation. However, the physiological significance of such oscillation remains unknown. Currently, the Class III PI 3-kinase (PI3K) Vps34 is regarded as the only kinase that produces PtdIns(3)P in phagosomal membranes. We report here that, in the nematode C. elegans, the Class II PI3K PIKI-1 plays a novel and crucial role in producing phagosomal PtdIns(3)P. PIKI-1 is recruited to extending pseudopods and nascent phagosomes prior to the appearance of PtdIns(3)P in a manner dependent on the large GTPase dynamin (DYN-1). PIKI-1 and VPS-34 act in sequence to provide overlapping pools of PtdIns(3)P on phagosomes. Inactivating both piki-1 and vps-34 completely abolishes the production of phagosomal PtdIns(3)P and disables phagosomes from recruiting multiple essential maturation factors, resulting in a complete arrest of apoptotic-cell degradation. We have further identified MTM-1, a PI 3-phosphatase that antagonizes the activities of PIKI-1 and VPS-34 by down-regulating PtdIns(3)P on phagosomes. Remarkably, persistent appearance of phagosomal PtdIns(3)P, as a result of inactivating mtm-1, blocks phagosome maturation. Our findings demonstrate that the proper oscillation pattern of PtdIns(3)P on phagosomes, programmed by the coordinated activities of two PI3Ks and one PI 3-phosphatase, is critical for phagosome maturation. They further shed light on how the temporally controlled reversible phosphorylation of phosphoinositides regulates the progression of multi-step cellular events. During animal development and in adulthood many cells are programmed to die by an active process called apoptosis. These dead or dying apoptotic cells are swiftly taken up by scavenger cells into membrane-bound compartments—phagosomes—where they are subsequently degraded when other intracellular organelles containing digestive enzymes fuse with phagosomes—a process called phagosome maturation. Phagocytosis of apoptotic cells is important for tissue remodeling in development and to prevent harmful inflammatory and autoimmune responses. In nematode worms—a model organism in which to study apoptosis—phagosome maturation is accompanied by two waves of the signaling molecule phosphatidylinositol 3-phosphate (PtdIns(3)P) in this compartment: one that forms soon after the formation of the phagosome and lasts for 10–15 minutes, and a second, weaker one 10 minutes later that lasts until the apoptotic cell is fully digested. In this study, we investigated the mechanism that regulates the timing and length of these two waves. We found that they are established by the sequential and combined action of three enzymes: two phosphoinositide 3-kinases, which add a phosphate group to the 3′ site of PtdIns, and one phosphoinositide 3-phosphatase, which removes it. We showed that inactivation of both kinases depleted phagosomes of PtdIns(3)P and resulted in the arrest of phagosome maturation and degradation of apoptotic cells. In addition, the timely turnover of PtdIns(3)P catalyzed by the phosphatase was critical for the step-wise progress of phagosome maturation. Our findings suggest that reversible phosphorylation of phophoinositides, catalyzed by distinct sets of kinases and phosphatases, might be a general mechanism to drive multi-step intracellular membrane trafficking events.
Collapse
Affiliation(s)
- Nan Lu
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Qian Shen
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Timothy R. Mahoney
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Lukas J. Neukomm
- Institute of Molecular Life Science, University of Zürich, Zürich, Switzerland
| | - Ying Wang
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Zheng Zhou
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
| |
Collapse
|
36
|
Abstract
Phosphoinositides (PIs) are minor components of cellular membranes that play critical regulatory roles in several intracellular functions. This chapter describes the main enzymes regulating the turnover of each of the seven PIs in mammalian cells and introduces to some of their intracellular functions and to some evidences of their involvement in human diseases. Due to the complex interrelation between the distinct PIs and the plethora of functions that they can regulate inside a cell, this chapter is not meant to be a comprehensive coverage of all aspects of PI signalling but rather an introduction to this complex signalling field. For more details of their regulation/functions and extensive description of their intracellular roles, more detailed reviews are suggested on each single topic.
Collapse
Affiliation(s)
- Tania Maffucci
- Centre for Diabetes, Blizard Institute, Inositide Signalling Group, Queen Mary University of London, Barts and The London School of Medicine and Dentistry, UK.
| |
Collapse
|
37
|
Multiple roles for the p85α isoform in the regulation and function of PI3K signalling and receptor trafficking. Biochem J 2011; 441:23-37. [DOI: 10.1042/bj20111164] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The p85α protein is best known as the regulatory subunit of class 1A PI3Ks (phosphoinositide 3-kinases) through its interaction, stabilization and repression of p110-PI3K catalytic subunits. PI3Ks play multiple roles in the regulation of cell survival, signalling, proliferation, migration and vesicle trafficking. The present review will focus on p85α, with special emphasis on its important roles in the regulation of PTEN (phosphatase and tensin homologue deleted on chromosome 10) and Rab5 functions. The phosphatidylinositol-3-phosphatase PTEN directly counteracts PI3K signalling through dephosphorylation of PI3K lipid products. Thus the balance of p85α–p110 and p85α–PTEN complexes determines the signalling output of the PI3K/PTEN pathway, and under conditions of reduced p85α levels, the p85α–PTEN complex is selectively reduced, promoting PI3K signalling. Rab5 GTPases are important during the endocytosis, intracellular trafficking and degradation of activated receptor complexes. The p85α protein helps switch off Rab5, and if defective in this p85α function, results in sustained activated receptor tyrosine kinase signalling and cell transformation through disrupted receptor trafficking. The central role for p85α in the regulation of PTEN and Rab5 has widened the scope of p85α functions to include integration of PI3K activation (p110-mediated), deactivation (PTEN-mediated) and receptor trafficking/signalling (Rab5-mediated) functions, all with key roles in maintaining cellular homoeostasis.
Collapse
|
38
|
Liu Z, Sun C, Zhang Y, Ji Z, Yang G. Phosphatidylinositol 3-Kinase-C2β Inhibits Cisplatin-Mediated Apoptosis via the Akt Pathway in Oesophageal Squamous Cell Carcinoma. J Int Med Res 2011; 39:1319-32. [PMID: 21986133 DOI: 10.1177/147323001103900419] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
A major problem in treating oesophageal squamous cell carcinoma (ESCC) with cisplatin is the development of drug resistance. In order to determine whether phosphatidylinositol 3-kinase (PI3K)-C2β (encoded by the PIK3C2B gene) reduced the sensitivity of ESCC to cisplatin, transfected Eca109 cells that overexpressed PIK3C2B were produced. Additionally, PI3K-C2β-siRNA was used to silence endogenous PI3K-C2β in EC9706 cisplatin-resistant cells. The relationship between PIK3C2B expression and clinicopathological characteristics was also investigated in samples from 61 patients. The overexpression of PIK3C2B in Eca109 cells significantly inhibited cisplatin-induced apoptosis and cleavage of caspase-3. Knockdown of PI3K-C2β enhanced cisplatin-induced apoptosis in EC9706 cells. PIK3C2B expression was associated with an increased level of phosphorylated Akt. Based on the tumour samples, expression of PIK3C2B was associated with tumour metastasis and in vitro assay suggested that it mediated cell migration. These results indicated that PI3K-C2β, via the Akt signalling pathway, might play a key role in cisplatin resistance and that targeting this pathway might be useful in treating cisplatin-resistant tumours.
Collapse
Affiliation(s)
- Z Liu
- Department of Oncology, Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - C Sun
- Department of Infectious Diseases, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Y Zhang
- Department of Pharmacology, College of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Z Ji
- Henan Academy of Medical and Pharmaceutical Science, Zhengzhou University, Zhengzhou, China
| | - G Yang
- Henan Academy of Medical and Pharmaceutical Science, Zhengzhou University, Zhengzhou, China
| |
Collapse
|
39
|
Requirement for class II phosphoinositide 3-kinase C2alpha in maintenance of glomerular structure and function. Mol Cell Biol 2010; 31:63-80. [PMID: 20974805 DOI: 10.1128/mcb.00468-10] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
An early lesion in many kidney diseases is damage to podocytes, which are critical components of the glomerular filtration barrier. A number of proteins are essential for podocyte filtration function, but the signaling events contributing to development of nephrotic syndrome are not well defined. Here we show that class II phosphoinositide 3-kinase C2α (PI3KC2α) is expressed in podocytes and plays a critical role in maintaining normal renal homeostasis. PI3KC2α-deficient mice developed chronic renal failure and exhibited a range of kidney lesions, including glomerular crescent formation and renal tubule defects in early disease, which progressed to diffuse mesangial sclerosis, with reduced podocytes, widespread effacement of foot processes, and modest proteinuria. These findings were associated with altered expression of nephrin, synaptopodin, WT-1, and desmin, indicating that PI3KC2α deficiency specifically impacts podocyte morphology and function. Deposition of glomerular IgA was observed in knockout mice; importantly, however, the development of severe glomerulonephropathy preceded IgA production, indicating that nephropathy was not directly IgA mediated. PI3KC2α deficiency did not affect immune responses, and bone marrow transplantation studies also indicated that the glomerulonephropathy was not the direct consequence of an immune-mediated disease. Thus, PI3KC2α is critical for maintenance of normal glomerular structure and function by supporting normal podocyte function.
Collapse
|
40
|
The α-isoform of class II phosphoinositide 3-kinase is necessary for the activation of ERK but not Akt/PKB. Mol Cell Biochem 2010; 346:95-101. [PMID: 20924651 DOI: 10.1007/s11010-010-0596-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Accepted: 09/18/2010] [Indexed: 01/02/2023]
Abstract
Phosphoinositide 3-kinases (PI3Ks) are key enzymes that activate intracellular signaling molecules when a number of different growth factors bind to cell surface receptors. PI3Ks are divided into three classes (I, II, III), and enzymes of each class have different tissue specificities and physiological functions. The α-isoform (PI3K-C2α) of class II PI3Ks is considered ubiquitous and preferentially activated by insulin. Our previous study showed that suppression of PI3K-C2α leads to apoptotic cell death. The aim of this study is to determine whether depletion of PI3K-C2α affects ERK or PKB/Akt activity following stimulation with serum and insulin growth factors in Chinese hamster ovary cells expressing human insulin receptors (CHO-IR) and human HepG2 liver cells. Different antisense oligonucleotides (ODNs), which were designed based on the sequence of the C2 domain of the human PI3K-C2α gene, were transfected into cells to inhibit PI3K-C2α expression. Insulin- or serum-induced stimulation of ERK was significantly suppressed by depletion of PI3K-C2α, whereas phosphorylation of IRS-1 and the stimulation of PKB/Akt by insulin were not affected. The number of apoptotic cells was also increased by depletion of PI3K-C2α protein levels. Taken together, our data indicate that PI3K-C2α may be a crucial factor in the stimulation of ERK activity in response to serum or insulin, whereas it is less important for the stimulation of PKB/Akt activity in response to insulin.
Collapse
|
41
|
Abstract
Phosphoinositide 3-kinases (PI3Ks) function early in intracellular signal transduction pathways and affect many biological functions. A further level of complexity derives from the existence of eight PI3K isoforms, which are divided into class I, class II and class III PI3Ks. PI3K signalling has been implicated in metabolic control, immunity, angiogenesis and cardiovascular homeostasis, and is one of the most frequently deregulated pathways in cancer. PI3K inhibitors have recently entered clinical trials in oncology. A better understanding of how the different PI3K isoforms are regulated and control signalling could uncover their roles in pathology and reveal in which disease contexts their blockade could be most beneficial.
Collapse
|
42
|
Leibiger B, Moede T, Uhles S, Barker CJ, Creveaux M, Domin J, Berggren PO, Leibiger IB. Insulin-feedback via PI3K-C2alpha activated PKBalpha/Akt1 is required for glucose-stimulated insulin secretion. FASEB J 2010; 24:1824-37. [PMID: 20061534 DOI: 10.1096/fj.09-148072] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Phosphatidylinositide 3-kinases (PI3Ks) play central roles in insulin signal transduction. While the contribution of class Ia PI3K members has been extensively studied, the role of class II members remains poorly understood. The diverse actions of class II PI3K-C2alpha have been attributed to its lipid product PI(3)P. By applying pharmacological inhibitors, transient overexpression and small-interfering RNA-based knockdown of PI3K and PKB/Akt isoforms, together with PI-lipid profiling and live-cell confocal and total internal reflection fluorescence microscopy, we now demonstrate that in response to insulin, PI3K-C2alpha generates PI(3,4)P(2), which allows the selective activation of PKBalpha/Akt1. Knockdown of PI3K-C2alpha expression and subsequent reduction of PKBalpha/Akt1 activity in the pancreatic beta-cell impaired glucose-stimulated insulin release, at least in part, due to reduced glucokinase expression and increased AS160 activity. Hence, our results identify signal transduction via PI3K-C2alpha as a novel pathway whereby insulin activates PKB/Akt and thus discloses PI3K-C2alpha as a potential drugable target in type 2 diabetes. The high degree of codistribution of PI3K-C2alpha and PKBalpha/Akt1 with insulin receptor B type, but not A type, in the same plasma membrane microdomains lends further support to the concept that selectivity in insulin signaling is achieved by the spatial segregation of signaling events.
Collapse
Affiliation(s)
- Barbara Leibiger
- Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | | | | | | | | | | | | | | |
Collapse
|
43
|
Vanhaesebroeck B, Vogt PK, Rommel C. PI3K: from the bench to the clinic and back. Curr Top Microbiol Immunol 2010; 347:1-19. [PMID: 20549473 DOI: 10.1007/82_2010_65] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
From humble beginnings over 25 years ago as a lipid kinase activity associated with certain oncoproteins, PI3K (phosphoinositide 3-kinase) has been catapulted to the forefront of drug development in cancer, immunity and thrombosis, with the first clinical trials of PI3K pathway inhibitors now in progress. Here, we give a brief overview of some key discoveries in the PI3K area and their impact, and include thoughts on the current state of the field, and where it could go from here.PI3K has become a very intense area of research, with over 2,000 publications on PI3K in PubMed for 2009 alone. The expectations for a therapeutic impact of intervention with PI3K activity are high, and progress in the clinical arena is being monitored by many. However, targeted therapies almost invariably encounter roadblocks, often exposing unresolved questions in the basic understanding of the target. PI3K will most likely be no exception. Below, we describe some of these early "surprises" and how these inform and shape basic science investigations.
Collapse
|
44
|
Abstract
The PI3-K family is one of the most intensely pursued classes of drug targets. This chapter reviews some of the chemical and structural features that determine the selectivity of PI3-K inhibitors, by focusing on a few key compounds that have been instrumental in guiding our understanding of how to design drugs against this family.
Collapse
|
45
|
Epidermal growth factor stimulates translocation of the class II phosphoinositide 3-kinase PI3K-C2beta to the nucleus. Biochem J 2009; 422:53-60. [PMID: 19496756 DOI: 10.1042/bj20090654] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Although the class II phosphoinositide 3-kinase enzymes PI3K-C2alpha and PI3K-C2beta act acutely downstream of cell surface receptors they have also been localized to nuclei in mammalian cells. As with the class I PI3K enzymes, the relationship between the pools of enzyme present in cytoplasm and nuclei remains poorly understood. In this study we test the hypothesis that PI3K-C2beta translocates to nuclei in response to growth factor stimulation. Fractionating homogenates of quiescent cells revealed that less than 5% of total PI3K-C2beta resides in nuclei. Stimulation with epidermal growth factor sequentially increased levels of this enzyme, firstly in the cytosol and secondly in the nuclei. Using detergent-treated nuclei, we showed that PI3K-C2beta co-localized with lamin A/C in the nuclear matrix. This was confirmed biochemically, and a phosphoinositide kinase assay showed a statistically significant increase in nuclear PI3K-C2beta levels and lipid kinase activity following epidermal growth factor stimulation. C-terminal deletion and point mutations of PI3K-C2beta demonstrated that epidermal growth factor-driven translocation to the nucleus is dependent on a sequence of basic amino acid residues (KxKxK) that form a nuclear localization motif within the C-terminal C2 domain. Furthermore, when this sequence was expressed as an EGFP (enhanced green fluorescent protein) fusion protein, it translocated fluorescence into nuclei with an efficiency dependent upon copy number. These data demonstrate that epidermal growth factor stimulates the appearance of PI3K-C2beta in nuclei. Further, this effect is dependent on a nuclear localization signal present within the C-terminal C2 domain, indicating its bimodal function regulating phospholipid binding and shuttling PI3K-C2beta into the nucleus.
Collapse
|
46
|
Sasaki T, Takasuga S, Sasaki J, Kofuji S, Eguchi S, Yamazaki M, Suzuki A. Mammalian phosphoinositide kinases and phosphatases. Prog Lipid Res 2009; 48:307-43. [PMID: 19580826 DOI: 10.1016/j.plipres.2009.06.001] [Citation(s) in RCA: 190] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Phosphoinositides are lipids that are present in the cytoplasmic leaflet of a cell's plasma and internal membranes and play pivotal roles in the regulation of a wide variety of cellular processes. Phosphoinositides are molecularly diverse due to variable phosphorylation of the hydroxyl groups of their inositol rings. The rapid and reversible configuration of the seven known phosphoinositide species is controlled by a battery of phosphoinositide kinases and phosphoinositide phosphatases, which are thus critical for phosphoinositide isomer-specific localization and functions. Significantly, a given phosphoinositide generated by different isozymes of these phosphoinositide kinases and phosphatases can have different biological effects. In mammals, close to 50 genes encode the phosphoinositide kinases and phosphoinositide phosphatases that regulate phosphoinositide metabolism and thus allow cells to respond rapidly and effectively to ever-changing environmental cues. Understanding the distinct and overlapping functions of these phosphoinositide-metabolizing enzymes is important for our knowledge of both normal human physiology and the growing list of human diseases whose etiologies involve these proteins. This review summarizes the structural and biological properties of all the known mammalian phosphoinositide kinases and phosphoinositide phosphatases, as well as their associations with human disorders.
Collapse
Affiliation(s)
- Takehiko Sasaki
- Department of Pathology and Immunology, Akita University, Graduate School of Medicine, Akita 010-8543, Japan.
| | | | | | | | | | | | | |
Collapse
|
47
|
Braccini L, Ciraolo E, Morello F, Lu X, Hirsch E. PI3K signaling: a crossroads of metabolic regulation. Expert Rev Endocrinol Metab 2009; 4:349-357. [PMID: 30781275 DOI: 10.1586/eem.09.19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Insulin exerts a fundamental role in glucose metabolism. Several lines of evidence have established PI3Ks as crucial signaling crossroads of metabolic regulation. These kinases play a key role in glucose homeostasis through the generation of lipid secondary messengers upon membrane receptor activation, thus regulating liver gluconeogenesis and glycogen synthesis. While class IA Pl3Kα historically appeared as the major PI3K isoform involved in insulin-mediated glucose metabolism, emerging evidence has demonstrated the contribution of other PI3K isoforms. In this review, we focus on the prototypical insulin receptor-PI3K pathway and on the effects of its impairment on metabolism, insulin sensitivity and the molecular pathophysiology of diabetes mellitus.
Collapse
Affiliation(s)
- Laura Braccini
- a Molecular Biotechnology Center, Via Nizza 52, 10126 Turin, Italy.
| | - Elisa Ciraolo
- b Molecular Biotechnology Center, Via Nizza 52, 10126 Turin, Italy.
| | - Fulvio Morello
- c Molecular Biotechnology Center, Via Nizza 52, 10126 Turin, Italy.
| | - Xiaoyun Lu
- d Molecular Biotechnology Center, Via Nizza 52, 10126 Turin, Italy.
| | - Emilio Hirsch
- e Professor, Molecular Biotechnology Center, Via Nizza 52, 10126 Turin, Italy.
| |
Collapse
|
48
|
Vascular endothelial growth factor acts through novel, pregnancy-enhanced receptor signalling pathways to stimulate endothelial nitric oxide synthase activity in uterine artery endothelial cells. Biochem J 2009; 417:501-11. [PMID: 18816248 DOI: 10.1042/bj20081013] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
During pregnancy, VEGF (vascular endothelial growth factor) regulates in part endothelial angiogenesis and vasodilation. In the present study we examine the relative roles of VEGFRs (VEGF receptors) and associated signalling pathways mediating the effects of VEGF(165) on eNOS (endothelial nitric oxide synthase) activation. Despite equal expression levels of VEGFR-1 and VEGFR-2 in UAECs (uterine artery endothelial cells) from NP (non-pregnant) and P (pregnant) sheep, VEGF(165) activates eNOS at a greater level in P- compared with NP-UAEC, independently of Akt activation. The selective VEGFR-1 agonist PlGF (placental growth factor)-1 elicits only a modest activation of eNOS in P-UAECs compared with VEGF(165), whereas the VEGFR-2 kinase inhibitor blocks VEGF(165)-stimulated eNOS activation, suggesting VEGF(165) predominantly activates eNOS via VEGFR-2. Although VEGF(165) also activates ERK (extracellular-signal-regulated kinase)-1/2, this is not necessary for eNOS activation since U0126 blocks ERK-1/2 phosphorylation, but not eNOS activation, and the VEGFR-2 kinase inhibitor inhibits eNOS activation, but not ERK-1/2 phosphorylation. Furthermore, the inability of PlGF to activate ERK-1/2 and the ability of the VEGFR-2 selective agonist VEGF-E to activate ERK-1/2 and eNOS suggests again that both eNOS and ERK-1/2 activation occur predominantly via VEGFR-2. The lack of VEGF(165)-stimulated Akt phosphorylation is consistent with a lack of robust phosphorylation of Ser(1179)-eNOS. Although VEGF(165)-stimulated eNOS phosphorylation is observed at Ser(617) and Ser(635), pregnancy does not significantly alter this response. Our finding that VEGF(165) activation of eNOS is completely inhibited by wortmannin but not LY294002 implies a downstream kinase, possibly a wortmannin-selective PI3K (phosphoinositide 3-kinase), is acting between the VEGFR-2 and eNOS independently of Akt.
Collapse
|
49
|
Abstract
The regulation of phosphoinositide (PI) 3-kinase activities has been linked to many normal and disease-related processes, including cell survival, cell growth and proliferation, cell differentiation, cell motility, and intracellular vesicle trafficking. However, as the family of enzymes has now grown to include eight true members, in three functional classes, plus several related protein kinases that are also inhibited by the widely used PI 3-kinase selective inhibitors, wortmannin and LY294002, extended methodologies are required to identify which type of kinase is involved in a particular cellular process, or protein complex, under study. A robust in vitro PI 3-kinase assay, suitable for use with immunoprecipitates, or purified proteins, is described here together with a series of modifications of substrate and assay conditions that will aid researchers in the identification of the particular class and isoform of PI 3-kinase that is involved in a signaling process under investigation.
Collapse
Affiliation(s)
- Michael J Fry
- School of Biological Sciences, Division of Biomolecular Science, University of Reading, Whiteknights, Reading, Berkshire, UK.
| |
Collapse
|
50
|
Elis W, Triantafellow E, Wolters NM, Sian KR, Caponigro G, Borawski J, Gaither LA, Murphy LO, Finan PM, Mackeigan JP. Down-regulation of class II phosphoinositide 3-kinase alpha expression below a critical threshold induces apoptotic cell death. Mol Cancer Res 2008; 6:614-23. [PMID: 18403640 DOI: 10.1158/1541-7786.mcr-07-0262] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Members of the phosphoinositide 3-kinase (PI3K) family collectively control multiple cellular responses, including proliferation, growth, chemotaxis, and survival. These diverse effects can partly be attributed to the broad range of downstream effectors being regulated by the products of these lipid kinases, the 3'-phosphoinositides. However, an additional layer of complexity is introduced by the existence of multiple PI3K enzyme isoforms. Much has been learned over the last years on the roles of the classes I and III PI3K members in cellular signaling, but little is known about the isoform-specific tasks done by the class II PI3Ks (C2alpha, beta, and gamma). In this study, we used quantitative reverse transcription-PCR and RNA interference in mammalian cells to gain further insight into the function of these lesser studied PI3K enzymes. We find that PI3K-C2alpha, but not PI3K-C2beta, has an important role in controlling cell survival and by using a panel of RNA interference reagents, we were able to determine a critical threshold of PI3K-C2alpha mRNA levels, below which the apoptotic program is switched on, via the intrinsic cell death pathway. In addition, knockdown of PI3K-C2alpha to levels that by themselves do not induce apoptosis sensitize cells to the anticancer agent Taxol (paclitaxel). Lastly, we report that lowering the levels of PI3K-C2alpha in a number of cancer cell lines reduces their proliferation and cell viability, arguing that PI3K inhibitors targeting not only the class Ialpha isoform but also class IIalpha may contribute to an effective anticancer strategy.
Collapse
Affiliation(s)
- Winfried Elis
- Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|