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Duewell BR, Wilson NE, Bailey GM, Peabody SE, Hansen SD. Molecular dissection of PI3Kβ synergistic activation by receptor tyrosine kinases, GβGγ, and Rho-family GTPases. eLife 2024; 12:RP88991. [PMID: 38713746 PMCID: PMC11076043 DOI: 10.7554/elife.88991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/09/2024] Open
Abstract
Phosphoinositide 3-kinase (PI3K) beta (PI3Kβ) is functionally unique in the ability to integrate signals derived from receptor tyrosine kinases (RTKs), G-protein coupled receptors, and Rho-family GTPases. The mechanism by which PI3Kβ prioritizes interactions with various membrane-tethered signaling inputs, however, remains unclear. Previous experiments did not determine whether interactions with membrane-tethered proteins primarily control PI3Kβ localization versus directly modulate lipid kinase activity. To address this gap in our knowledge, we established an assay to directly visualize how three distinct protein interactions regulate PI3Kβ when presented to the kinase in a biologically relevant configuration on supported lipid bilayers. Using single molecule Total Internal Reflection Fluorescence (TIRF) Microscopy, we determined the mechanism controlling PI3Kβ membrane localization, prioritization of signaling inputs, and lipid kinase activation. We find that auto-inhibited PI3Kβ prioritizes interactions with RTK-derived tyrosine phosphorylated (pY) peptides before engaging either GβGγ or Rac1(GTP). Although pY peptides strongly localize PI3Kβ to membranes, stimulation of lipid kinase activity is modest. In the presence of either pY/GβGγ or pY/Rac1(GTP), PI3Kβ activity is dramatically enhanced beyond what can be explained by simply increasing membrane localization. Instead, PI3Kβ is synergistically activated by pY/GβGγ and pY/Rac1 (GTP) through a mechanism consistent with allosteric regulation.
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Affiliation(s)
- Benjamin R Duewell
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of OregonEugeneUnited States
| | - Naomi E Wilson
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of OregonEugeneUnited States
| | - Gabriela M Bailey
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of OregonEugeneUnited States
| | - Sarah E Peabody
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of OregonEugeneUnited States
| | - Scott D Hansen
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of OregonEugeneUnited States
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2
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Peña KA, Savransky S, Lewis B. Endosomal signaling via cAMP in parathyroid hormone (PTH) type 1 receptor biology. Mol Cell Endocrinol 2024; 581:112107. [PMID: 37981188 DOI: 10.1016/j.mce.2023.112107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 10/25/2023] [Accepted: 11/06/2023] [Indexed: 11/21/2023]
Abstract
Compartmentalization of GPCR signaling is an emerging topic that highlights the physiological relevance of spatial bias in signaling. The parathyroid hormone (PTH) type 1 receptor (PTH1R) was the first GPCR described to signal via heterotrimeric G-protein and cAMP from endosomes after β-arrestin mediated internalization, challenging the canonical GPCR signaling model which established that signaling is terminated by receptor internalization. More than a decade later, many other GPCRs have been shown to signal from endosomes via cAMP, and recent studies have proposed that location of cAMP generation impacts physiological outcomes of GPCR signaling. Here, we review the extensive literature regarding PTH1R endosomal signaling via cAMP, the mechanisms that regulate endosomal generation of cAMP, and the implications of spatial bias in PTH1R physiological functions.
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Affiliation(s)
- Karina A Peña
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
| | - Sofya Savransky
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Graduate Program in Molecular Pharmacology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Breanna Lewis
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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3
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Duewell BR, Wilson NE, Bailey GM, Peabody SE, Hansen SD. Molecular dissection of PI3Kβ synergistic activation by receptor tyrosine kinases, GβGγ, and Rho-family GTPases. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.01.538969. [PMID: 37205345 PMCID: PMC10187233 DOI: 10.1101/2023.05.01.538969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The class 1A phosphoinositide 3-kinase (PI3K) beta (PI3Kβ) is functionally unique in the ability to integrate signals derived from receptor tyrosine kinases (RTKs), heterotrimeric guanine nucleotide-binding protein (G-protein)-coupled receptors (GPCRs), and Rho-family GTPases. The mechanism by which PI3Kβ prioritizes interactions with various membrane tethered signaling inputs, however, remains unclear. Previous experiments have not been able to elucidate whether interactions with membrane-tethered proteins primarily control PI3Kβ localization versus directly modulate lipid kinase activity. To address this gap in our understanding of PI3Kβ regulation, we established an assay to directly visualize and decipher how three distinct protein interactions regulate PI3Kβ when presented to the kinase in a biologically relevant configuration on supported lipid bilayers. Using single molecule Total Internal Reflection Fluorescence (TIRF) Microscopy, we determined the mechanism controlling membrane localization of PI3Kβ, prioritization of signaling inputs, and lipid kinase activation. We find that auto-inhibited PI3Kβ prioritizes interactions with RTK-derived tyrosine phosphorylated (pY) peptides before engaging either GβGγ or Rac1(GTP). Although pY peptides strongly localize PI3Kβ to membranes, stimulation of lipid kinase activity is modest. In the presence of either pY/GβGγ or pY/Rac1(GTP), PI3Kβ activity is dramatically enhanced beyond what can be explained by simply increasing the strength of membrane localization. Instead, PI3Kβ is synergistically activated by pY/GβGγ and pY/Rac1(GTP) through a mechanism consistent with allosteric regulation.
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4
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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.
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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.
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5
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Li J, Xiao Y, Yu H, Jin X, Fan S, Liu W. Mutual connected IL-6, EGFR and LIN28/Let7-related mechanisms modulate PD-L1 and IGF upregulation in HNSCC using immunotherapy. Front Oncol 2023; 13:1140133. [PMID: 37124491 PMCID: PMC10130400 DOI: 10.3389/fonc.2023.1140133] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 03/28/2023] [Indexed: 05/02/2023] Open
Abstract
The development of techniques and immunotherapies are widely applied in cancer treatment such as checkpoint inhibitors, adoptive cell therapy, and cancer vaccines apart from radiation therapy, surgery, and chemotherapy give enduring anti-tumor effects. Minority people utilize single-agent immunotherapy, and most people adopt multiple-agent immunotherapy. The difficulties are resolved by including the biomarkers to choose the non-responders' and responders' potentials. The possibility of the potential complications and side effects are examined to improve cancer therapy effects. The Head and Neck Squamous Cell Carcinoma (HNSCC) is analyzed with the help of programmed cell death ligand 1 (PD-L1) and Insulin-like growth factor (IGF). But how IGF and PD-L1 upregulation depends on IL-6, EGFR, and LIN28/Let7-related mechanisms are poorly understood. Briefly, IL-6 stimulates gene expressions of IGF-1/2, and IL-6 cross-activates IGF-1R signaling, NF-κB, and STAT3. NF-κB, up-regulating PD-L1 expressions. IL-6/JAK1 primes PD-L1 for STT3-mediated PD-L1 glycosylation, stabilizes PD-L1 and trafficks it to the cell surface. Moreover, ΔNp63 is predominantly overexpressed over TAp63 in HNSCC, elevates circulating IGF-1 levels by repressing IGFBP3, and activates insulin receptor substrate 1 (IRS1).TP63 and SOX2 form a complex with CCAT1 to promote EGFR expression. EGFR activation through EGF binding extends STAT3 activation, and EGFR and its downstream signaling prolong PD-L1 mRNA half-life. PLC-γ1 binding to a cytoplasmic motif of elevated PD-L1 improves EGF-induced activation of inositol 1,4,5-tri-phosphate (IP3), and diacylglycerol (DAG) subsequently elevates RAC1-GTP. RAC1-GTP was convincingly demonstrated to induce the autocrine production and action of IL-6/IL-6R, forming a feedback loop for IGF and PD-L1 upregulation. Furthermore, the LIN28-Let7 axis mediates the NF-κB-IL-6-STAT3 amplification loop, activated LIN28-Let7 axis up-regulates RAS, AKT, IL-6, IGF-1/2, IGF-1R, Myc, and PD-L1, plays pivotal roles in IGF-1R activation and Myc, NF-κB, STAT3 concomitant activation. Therefore, based on a detailed mechanisms review, our article firstly reveals that IL-6, EGFR, and LIN28/Let7-related mechanisms mediate PD-L1 and IGF upregulation in HNSCC, which comprehensively influences immunity, inflammation, metabolism, and metastasis in the tumor microenvironment, and might be fundamental for overcoming therapy resistance.
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Affiliation(s)
- Junjun Li
- Department of Pathology, Hunan Cancer Hospital, The Affiliated Cancer Hospital of The Xiangya School of Medicine, Central South University, Changsha, China
| | - Yazhou Xiao
- Department of Pathology, Hunan Cancer Hospital, The Affiliated Cancer Hospital of The Xiangya School of Medicine, Central South University, Changsha, China
| | - Huayue Yu
- Department of Pathology, Hunan Cancer Hospital, The Affiliated Cancer Hospital of The Xiangya School of Medicine, Central South University, Changsha, China
| | - Xia Jin
- Department of Pathology, Hunan Cancer Hospital, The Affiliated Cancer Hospital of The Xiangya School of Medicine, Central South University, Changsha, China
| | - Songqing Fan
- Department of Pathology, Hunan Cancer Hospital, The Affiliated Cancer Hospital of The Xiangya School of Medicine, Central South University, Changsha, China
- Department of Pathology, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Wei Liu
- Department of Pathology, Hunan Cancer Hospital, The Affiliated Cancer Hospital of The Xiangya School of Medicine, Central South University, Changsha, China
- Department of Pathology, The Second Xiangya Hospital, Central South University, Changsha, China
- *Correspondence: Wei Liu,
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6
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Peña KA. Endosomal parathyroid hormone receptor signaling. Am J Physiol Cell Physiol 2022; 323:C783-C790. [PMID: 35912987 PMCID: PMC9467467 DOI: 10.1152/ajpcell.00452.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 07/20/2022] [Accepted: 07/25/2022] [Indexed: 11/22/2022]
Abstract
The canonical model for G protein-coupled receptors (GPCRs) activation assumes that stimulation of heterotrimeric G protein signaling upon ligand binding occurs solely at the cell surface and that duration of the stimulation is transient to prevent overstimulation. In this model, GPCR signaling is turned-off by receptor phosphorylation via GPCR kinases (GRKs) and subsequent recruitment of β-arrestins, resulting in receptor internalization into endosomes. Internalized receptors can then recycle back to the cell surface or be trafficked to lysosomes for degradation. However, over the last decade, this model has been extended by discovering that some internalized GPCRs continue to signal via G proteins from endosomes. This is the case for the parathyroid hormone (PTH) type 1 receptor (PTHR), which engages on sustained cAMP signaling from endosomes upon PTH stimulation. Accumulative evidence shows that the location of signaling has an impact on the physiological effects of GPCR signaling. This mini-review discusses recent insights into the mechanisms of PTHR endosomal signaling and its physiological impact.
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Affiliation(s)
- Karina A Peña
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
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7
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Luo Y, Gou H, Chen X, Li L, Wang X, Xu Y. Lactate inhibits osteogenic differentiation of human periodontal ligament stem cells via autophagy through the MCT1-mTOR signaling pathway. Bone 2022; 162:116444. [PMID: 35589065 DOI: 10.1016/j.bone.2022.116444] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Revised: 05/11/2022] [Accepted: 05/11/2022] [Indexed: 11/02/2022]
Abstract
BACKGROUND Periodontal ligament stem cells (PDLSCs) play a crucial role in periodontal bone regeneration. Lactate used to be considered a waste product of glucose metabolism. In recent years, a few pieces of evidence revealed its roles in regulating the osteogenic differentiation of stem cells, but the standpoints were controversial. This study aims to investigate the effects and the mechanisms of lactate on the osteogenic differentiation of human periodontal ligament stem cells (hPDLSCs). METHODS The hPDLSCs were treated with different concentrations of lactic acid and lactate to differentiate the effects of the acidic PH and ion lactate. Proliferation and cytotoxicity were measured by Cell Counting Kit-8 (CCK8) assay and Live/Dead assay. The osteogenic differentiation of hPDLSCs was analyzed by alizarin red staining, alkaline phosphatase (ALP) staining, and then osteogenic proteins and genes were measured by western blot and reverse transcription-quantitative PCR (qRT-PCR). To investigate the potential signaling pathways, MCT1 inhibitor, G-protein inhibitors, and rapamycin were used, and then autophagy-related proteins and osteogenic proteins were measured by western blot. RESULTS The inhibition of lactic acid on the osteogenic differentiation of hPDLSCs was more significant than lactate at the same concentration. Lactate inhibited the expression of ALP which can be rescued by Gα inhibitor. Alizarin red staining, the protein expression levels of osteocalcin (OCN), osteoprotegerin (OPN), osterix (OSX), and beclin1, LC3-II/LC3-I were decreased by lactate and partly rescued by MCT1 inhibitor. Rapamycin restored the protein expression levels of beclin1, LC3-II/LC3-I and OCN, OPN, OSX under the high lactate conditions. CONCLUSIONS Lactate inhibits the expression of ALP via Gα subunit signaling, and inhibits mineralized nodules formation and the expression of osteogenic-related proteins via reducing autophagy through the MCT1-mTOR signaling pathway.
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Affiliation(s)
- Ying Luo
- Jiangsu Province Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, People's Republic of China; Department of Periodontics, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, People's Republic of China; Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, Nanjing, People's Republic of China
| | - Huiqing Gou
- Jiangsu Province Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, People's Republic of China; Department of Periodontics, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, People's Republic of China; Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, Nanjing, People's Republic of China
| | - Xu Chen
- Jiangsu Province Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, People's Republic of China; Department of Periodontics, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, People's Republic of China; Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, Nanjing, People's Republic of China
| | - Lu Li
- Jiangsu Province Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, People's Republic of China; Department of Periodontics, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, People's Republic of China; Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, Nanjing, People's Republic of China
| | - Xiaoqian Wang
- Jiangsu Province Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, People's Republic of China; Department of Periodontics, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, People's Republic of China; Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, Nanjing, People's Republic of China
| | - Yan Xu
- Jiangsu Province Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, People's Republic of China; Department of Periodontics, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, People's Republic of China; Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, Nanjing, People's Republic of China.
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8
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The efficacy of PI3Kγ and EGFR inhibitors on the suppression of the characteristics of cancer stem cells. Sci Rep 2022; 12:347. [PMID: 35013447 PMCID: PMC8748513 DOI: 10.1038/s41598-021-04265-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Accepted: 12/15/2021] [Indexed: 12/11/2022] Open
Abstract
Cancer stem cells (CSCs) are capable of continuous proliferation, self-renewal and are proposed to play significant roles in oncogenesis, tumor growth, metastasis and cancer recurrence. We have established a model of CSCs that was originally developed from mouse induced pluripotent stem cells (miPSCs) by proposing miPSCs to the conditioned medium (CM) of cancer derived cells, which is a mimic of carcinoma microenvironment. Further research found that not only PI3K-Akt but also EGFR signaling pathway was activated during converting miPSCs into CSCs. In this study, we tried to observe both of PI3Kγ inhibitor Eganelisib and EGFR inhibitor Gefitinib antitumor effects on the models of CSCs derived from miPSCs (miPS-CSC) in vitro and in vivo. As the results, targeting these two pathways exhibited significant inhibition of cell proliferation, self-renewal, migration and invasion abilities in vitro. Both Eganelisib and Gefitinib showed antitumor effects in vivo while Eganelisib displayed more significant therapeutic efficacy and less side effects than Gefitinib on all miPS-CSC models. Thus, these data suggest that the inhibitiors of PI3K and EGFR, especially PI3Kγ, might be a promising therapeutic strategy against CSCs defeating cancer in the near future.
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9
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PI3K and AKT at the Interface of Signaling and Metabolism. Curr Top Microbiol Immunol 2022; 436:311-336. [DOI: 10.1007/978-3-031-06566-8_13] [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]
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10
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Class I PI3K Biology. Curr Top Microbiol Immunol 2022; 436:3-49. [DOI: 10.1007/978-3-031-06566-8_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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11
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Schrottmaier WC, Mussbacher M, Salzmann M, Kral-Pointner JB, Assinger A. PI3K Isoform Signalling in Platelets. Curr Top Microbiol Immunol 2022; 436:255-285. [PMID: 36243848 DOI: 10.1007/978-3-031-06566-8_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Platelets are unique anucleated blood cells that constantly patrol the vasculature to seal and prevent injuries in a process termed haemostasis. Thereby they rapidly adhere to the subendothelial matrix and recruit further platelets, resulting in platelet aggregates. Apart from their central role in haemostasis, they also kept some of their features inherited by their evolutionary ancestor-the haemocyte, which was also involved in immune defences. Together with leukocytes, platelets fight pathogenic invaders and guide many immune processes. In addition, they rely on several signalling pathways which are also relevant to immune cells. Among these, one of the central signalling hubs is the PI3K pathway. Signalling processes in platelets are unique as they lack a nucleus and therefore transcriptional regulation is absent. As a result, PI3K subclasses fulfil distinct roles in platelets compared to other cells. In contrast to leukocytes, the central PI3K subclass in platelet signalling is PI3K class Iβ, which underlines the uniqueness of this cell type and opens new ways for potential platelet-specific pharmacologic inhibition. An overview of platelet function and signalling with emphasis on PI3K subclasses and their respective inhibitors is given in this chapter.
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Affiliation(s)
- Waltraud C Schrottmaier
- Department of Vascular Biology and Thrombosis Research, Centre of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Marion Mussbacher
- Department of Pharmacology and Toxicology, University of Graz, Graz, Austria
- Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, USA
| | - Manuel Salzmann
- Division of Cardiology, Department of Internal Medicine II, Medical University of Vienna, Vienna, Austria
| | - Julia B Kral-Pointner
- Division of Cardiology, Department of Internal Medicine II, Medical University of Vienna, Vienna, Austria
- Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria
| | - Alice Assinger
- Department of Vascular Biology and Thrombosis Research, Centre of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria.
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Organismal roles for the PI3Kα and β isoforms: their specificity, redundancy or cooperation is context-dependent. Biochem J 2021; 478:1199-1225. [DOI: 10.1042/bcj20210004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/16/2021] [Accepted: 02/22/2021] [Indexed: 02/07/2023]
Abstract
PI3Ks are important lipid kinases that produce phosphoinositides phosphorylated in position 3 of the inositol ring. There are three classes of PI3Ks: class I PI3Ks produce PIP3 at plasma membrane level. Although D. melanogaster and C. elegans have only one form of class I PI3K, vertebrates have four class I PI3Ks called isoforms despite being encoded by four different genes. Hence, duplication of these genes coincides with the acquisition of coordinated multi-organ development. Of the class I PI3Ks, PI3Kα and PI3Kβ, encoded by PIK3CA and PIK3CB, are ubiquitously expressed. They present similar putative protein domains and share PI(4,5)P2 lipid substrate specificity. Fifteen years after publication of their first isoform-selective pharmacological inhibitors and genetically engineered mouse models (GEMMs) that mimic their complete and specific pharmacological inhibition, we review the knowledge gathered in relation to the redundant and selective roles of PI3Kα and PI3Kβ. Recent data suggest that, further to their redundancy, they cooperate for the integration of organ-specific and context-specific signal cues, to orchestrate organ development, physiology, and disease. This knowledge reinforces the importance of isoform-selective inhibitors in clinical settings.
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13
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Akbari Dilmaghani N, Safaroghli-Azar A, Pourbagheri-Sigaroodi A, Bashash D. The PI3K/Akt/mTORC signaling axis in head and neck squamous cell carcinoma: Possibilities for therapeutic interventions either as single agents or in combination with conventional therapies. IUBMB Life 2021; 73:618-642. [PMID: 33476088 DOI: 10.1002/iub.2446] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 12/24/2020] [Indexed: 01/08/2023]
Abstract
The latest advances in the sequencing methods in head and neck squamous cell carcinoma (HNSCC) tissues have revolutionized our understanding of the disease by taking off the veil from the most frequent genetic alterations in the components of the oncogenic pathways. Among all the identified alterations, aberrancies in the genes attributed to the phosphoinositide 3-kinases (PI3K) axis have attracted special attention as they were altered in more than 90% of the tissues isolated from HNSCC patients. In fact, the association between these aberrancies and the increased risk of cancer metastasis suggested this axis as an "Achilles Heel" of HNSCC, which may be therapeutically targeted. The results of the clinical trials investigating the therapeutic potential of the inhibitors targeting the components of the PI3K axis in the treatment of HNSCC patients, either alone or in a combined-modal strategy, opened a new chapter in the treatment strategy of this malignancy. The present study aimed to review the importance of the PI3K axis in the pathogenesis of HNSCC and also provide a piece of information about the breakthroughs and challenges of PI3K inhibitors in the therapeutic strategies of the disease.
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Affiliation(s)
- Nader Akbari Dilmaghani
- Hearing Disorders Research Center, Loghman Hakim Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Department of Otolaryngology, Head and Neck Surgery, Loghman Hakim Educational Hospital, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Ava Safaroghli-Azar
- 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
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14
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Lactate induces synapse-specific potentiation on CA3 pyramidal cells of rat hippocampus. PLoS One 2020; 15:e0242309. [PMID: 33180836 PMCID: PMC7660554 DOI: 10.1371/journal.pone.0242309] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 10/31/2020] [Indexed: 02/07/2023] Open
Abstract
Neuronal activity within the physiologic range stimulates lactate production that, via metabolic pathways or operating through an array of G-protein-coupled receptors, regulates intrinsic excitability and synaptic transmission. The recent discovery that lactate exerts a tight control of ion channels, neurotransmitter release, and synaptic plasticity-related intracellular signaling cascades opens up the possibility that lactate regulates synaptic potentiation at central synapses. Here, we demonstrate that extracellular lactate (1–2 mM) induces glutamatergic potentiation on the recurrent collateral synapses of hippocampal CA3 pyramidal cells. This potentiation is independent of lactate transport and further metabolism, but requires activation of NMDA receptors, postsynaptic calcium accumulation, and activation of a G-protein-coupled receptor sensitive to cholera toxin. Furthermore, perfusion of 3,5- dihydroxybenzoic acid, a lactate receptor agonist, mimics this form of synaptic potentiation. The transduction mechanism underlying this novel form of synaptic plasticity requires G-protein βγ subunits, inositol-1,4,5-trisphosphate 3-kinase, PKC, and CaMKII. Activation of these signaling cascades is compartmentalized in a synapse-specific manner since lactate does not induce potentiation at the mossy fiber synapses of CA3 pyramidal cells. Consistent with this synapse-specific potentiation, lactate increases the output discharge of CA3 neurons when recurrent collaterals are repeatedly activated during lactate perfusion. This study provides new insights into the cellular mechanisms by which lactate, acting via a membrane receptor, contributes to the memory formation process.
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15
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Zecchin D, Moore C, Michailidis F, Horswell S, Rana S, Howell M, Downward J. Combined targeting of G protein-coupled receptor and EGF receptor signaling overcomes resistance to PI3K pathway inhibitors in PTEN-null triple negative breast cancer. EMBO Mol Med 2020; 12:e11987. [PMID: 32672423 PMCID: PMC7411640 DOI: 10.15252/emmm.202011987] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 06/09/2020] [Accepted: 06/16/2020] [Indexed: 12/12/2022] Open
Abstract
Triple-negative breast cancer (TNBC) has poorer prognosis compared to other types of breast cancers due to the lack of effective therapies and markers for patient stratification. Loss of PTEN tumor suppressor gene expression is a frequent event in TNBC, resulting in over-activation of the PI 3-kinase (PI3K) pathway and sensitivity to its inhibition. However, PI3K pathway inhibitors show limited efficacy as monotherapies on these tumors. We report a whole-genome screen to identify targets whose inhibition enhanced the effects of different PI3K pathway inhibitors on PTEN-null TNBC. This identified a signaling network that relies on both the G protein-coupled receptor for thrombin (PAR1/F2R) and downstream G protein βγ subunits and also epidermal growth factor receptor (EGFR) for the activation of the PI3K isoform p110β and AKT. Compensation mechanisms involving these two branches of the pathway could bypass PI3K blockade, but combination targeting of both EGFR and PI3Kβ suppressed ribosomal protein S6 phosphorylation and exerted anti-tumor activity both in vitro and in vivo, suggesting a new potential therapeutic strategy for PTEN-null TNBC.
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Affiliation(s)
| | | | | | | | - Sareena Rana
- Oncogene BiologyFrancis Crick InstituteLondonUK
- Lung Cancer GroupInstitute of Cancer ResearchLondonUK
| | - Michael Howell
- High Throughput Screening LaboratoriesFrancis Crick InstituteLondonUK
| | - Julian Downward
- Oncogene BiologyFrancis Crick InstituteLondonUK
- Lung Cancer GroupInstitute of Cancer ResearchLondonUK
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16
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Rather Z, Banday JA, Chisti H. Spectroscopic, X‐ray Crystal, DFT and In Vitro Analysis of 3‐(2,4‐Dimethoxy‐3‐(3‐methylbut‐2‐en‐1‐yl)phenyl) Acrylic Acid. ChemistrySelect 2020. [DOI: 10.1002/slct.202001491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Zubaid‐ul‐khazir Rather
- Department of ChemistryNational Institute of Technology Srinagar Srinagar 190006, J & K India
| | - Javid A. Banday
- Department of ChemistryNational Institute of Technology Srinagar Srinagar 190006, J & K India
| | - Hamida‐Tun‐Nisa Chisti
- Department of ChemistryNational Institute of Technology Srinagar Srinagar 190006, J & K India
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17
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G q/11-dependent regulation of endosomal cAMP generation by parathyroid hormone class B GPCR. Proc Natl Acad Sci U S A 2020; 117:7455-7460. [PMID: 32184323 DOI: 10.1073/pnas.1918158117] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
cAMP production upon activation of Gs by G protein-coupled receptors has classically been considered to be plasma membrane-delimited, but a shift in this paradigm has occurred in recent years with the identification of several receptors that continue to signal from early endosomes after internalization. The molecular mechanisms regulating this aspect of signaling remain incompletely understood. Here, we investigated the role of Gq/11 activation by the parathyroid hormone (PTH) type 1 receptor (PTHR) in mediating endosomal cAMP responses. Inhibition of Gq/11 signaling by FR900359 markedly reduced the duration of PTH-induced cAMP production, and this effect was mimicked in cells lacking endogenous Gαq/11 We determined that modulation of cAMP generation by Gq/11 occurs at the level of the heterotrimeric G protein via liberation of cell surface Gβγ subunits, which, in turn, act in a phosphoinositide-3 kinase-dependent manner to promote the assembly of PTHR-βarrestin-Gβγ signaling complexes that mediate endosomal cAMP responses. These results unveil insights into the spatiotemporal regulation of Gs-dependent cAMP signaling.
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18
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Durrant TN, Hers I. PI3K inhibitors in thrombosis and cardiovascular disease. Clin Transl Med 2020; 9:8. [PMID: 32002690 PMCID: PMC6992830 DOI: 10.1186/s40169-020-0261-6] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 01/13/2020] [Indexed: 12/15/2022] Open
Abstract
Phosphoinositide 3-kinases (PI3Ks) are lipid kinases that regulate important intracellular signalling and vesicle trafficking events via the generation of 3-phosphoinositides. Comprising eight core isoforms across three classes, the PI3K family displays broad expression and function throughout mammalian tissues, and the (patho)physiological roles of these enzymes in the cardiovascular system present the PI3Ks as potential therapeutic targets in settings such as thrombosis, atherosclerosis and heart failure. This review will discuss the PI3K enzymes and their roles in cardiovascular physiology and disease, with a particular focus on platelet function and thrombosis. The current progress and future potential of targeting the PI3K enzymes for therapeutic benefit in cardiovascular disease will be considered, while the challenges of developing drugs against these master cellular regulators will be discussed.
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Affiliation(s)
- Tom N Durrant
- Department of Chemistry, University of Oxford, Oxford, OX1 3QZ, UK.
| | - Ingeborg Hers
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University Walk, Bristol, BS8 1TD, UK.
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19
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Smrcka AV, Fisher I. G-protein βγ subunits as multi-functional scaffolds and transducers in G-protein-coupled receptor signaling. Cell Mol Life Sci 2019; 76:4447-4459. [PMID: 31435698 PMCID: PMC6842434 DOI: 10.1007/s00018-019-03275-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 08/05/2019] [Accepted: 08/12/2019] [Indexed: 02/08/2023]
Abstract
G-protein βγ subunits are key participants in G-protein signaling. These subunits facilitate interactions between receptors and G proteins that are critical for the G protein activation cycle at the plasma membrane. In addition, they play roles in directly transducing signals to an ever expanding range of downstream targets, including integral membrane and cytosolic proteins. Emerging data indicate that Gβγ may play additional roles at intracellular compartments including endosomes, the Golgi apparatus, and the nucleus. Here, we discuss the molecular and structural basis for their ability to coordinate this wide range of cellular activities.
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Affiliation(s)
- Alan V Smrcka
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, 48104, USA.
| | - Isaac Fisher
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, 48104, USA
- Department of Pharmacology and Physiology, University of Rochester School of Medicine, Rochester, NY, 14629, USA
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20
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Rathinaswamy MK, Burke JE. Class I phosphoinositide 3-kinase (PI3K) regulatory subunits and their roles in signaling and disease. Adv Biol Regul 2019; 75:100657. [PMID: 31611073 DOI: 10.1016/j.jbior.2019.100657] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 09/23/2019] [Accepted: 09/25/2019] [Indexed: 02/06/2023]
Abstract
The Class I phosphoinositide 3-kinases (PI3Ks) are a group of heterodimeric lipid kinases that regulate crucial cellular processes including proliferation, survival, growth, and metabolism. The diversity in functions controlled by the various catalytic isoforms (p110α, p110β, p110δ, and p110γ) depends on their abilities to be activated by distinct stimuli such as receptor tyrosine kinases (RTKs), G-protein coupled receptors (GPCRs), and the Ras family of small G-proteins. A major factor determining the ability of each p110 enzyme to be activated is the presence of regulatory binding partners. Given the overwhelming evidence for the involvement of PI3Ks in diseases such as cancer, inflammation, immunodeficiency and diabetes, an understanding of how these regulatory proteins influence PI3K function is essential. This article highlights research deciphering the role of regulatory subunits in PI3K signaling and their involvement in human disease.
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Affiliation(s)
- Manoj K Rathinaswamy
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, V8W 2Y2, Canada
| | - John E Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, V8W 2Y2, Canada.
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21
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Bresnick AR, Backer JM. PI3Kβ-A Versatile Transducer for GPCR, RTK, and Small GTPase Signaling. Endocrinology 2019; 160:536-555. [PMID: 30601996 PMCID: PMC6375709 DOI: 10.1210/en.2018-00843] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 12/20/2018] [Indexed: 12/17/2022]
Abstract
The phosphoinositide 3-kinase (PI3K) family includes eight distinct catalytic subunits and seven regulatory subunits. Only two PI3Ks are directly regulated downstream from G protein-coupled receptors (GPCRs): the class I enzymes PI3Kβ and PI3Kγ. Both enzymes produce phosphatidylinositol 3,4,5-trisposphate in vivo and are regulated by both heterotrimeric G proteins and small GTPases from the Ras or Rho families. However, PI3Kβ is also regulated by direct interactions with receptor tyrosine kinases (RTKs) and their tyrosine phosphorylated substrates, and similar to the class II and III PI3Ks, it binds activated Rab5. The unusually complex regulation of PI3Kβ by small and trimeric G proteins and RTKs leads to a rich landscape of signaling responses at the cellular and organismic levels. This review focuses first on the regulation of PI3Kβ activity in vitro and in cells, and then summarizes the biology of PI3Kβ signaling in distinct tissues and in human disease.
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Affiliation(s)
- Anne R Bresnick
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York
| | - Jonathan M Backer
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York
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22
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Heitz SD, Hamelin DJ, Hoffmann RM, Greenberg N, Salloum G, Erami Z, Khalil BD, Shymanets A, Steidle EA, Gong GQ, Nürnberg B, Burke JE, Flanagan JU, Bresnick AR, Backer JM. A single discrete Rab5-binding site in phosphoinositide 3-kinase β is required for tumor cell invasion. J Biol Chem 2019; 294:4621-4633. [DOI: 10.1074/jbc.ra118.006032] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 01/15/2019] [Indexed: 11/06/2022] Open
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23
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24
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Farooq S, Banday JA, Hussain A, Nazir M, Qurishi MA, Hamid A, Koul S. Synthesis and Biological Evaluation of Novel Osthol Derivatives as Potent Cytotoxic Agents. Med Chem 2018; 15:138-149. [PMID: 30207222 DOI: 10.2174/1573406414666180911161047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Revised: 05/15/2018] [Accepted: 09/03/2018] [Indexed: 11/22/2022]
Abstract
BACKGROUND Natural product, osthol has been found to have important biological and pharmacological roles particularly having inhibitory effect on multiple types of cancer. OBJECTIVE The unmet needs in cancer therapeutics make its derivatization an important and exciting field of research. Keeping this in view, a whole new series of diverse analogues of osthol (1) were synthesized. METHOD All the newly synthesized compounds were made through modification in the lactone ring as well as in the side chain of the osthol molecule and were subjected to anti-proliferative screening through 3-(4,5-Dimethylthiazol-yl)-diphenyl tetrazoliumbromide (MTT) against four different human cancers of diverse origins viz. Colon (Colo-205), lung (A549), Leukemia (THP- 1) and breast (MCF-7) including SV40 transformed normal breast epithelial cell (fR-2). RESULTS Interestingly, among the tested molecules, most of the analogs displayed better antiproliferative activity than the parent Osthol 1. However, among all the tested analogs, compound 28 exhibited the best results against leukemia (THP1) cell line with IC50 of 5µM.Compound 28 induced potent apoptotic effects and G1 phase arrest in leukemia cancer cells (THP1). The population of apoptotic cells increased from 13.8% in negative control to 26.9% at 8μM concentration of 28. Compound 28 also induced a remarkable decrease in mitochondrial membrane potential (ΛΨm) leading to apoptosis of the cancer cells. CONCLUSION A novel series of molecules derived from natural product osthol were synthesized, wherein compound 28 was found to be most effective against leukemia and with 10 fold less toxicity against normal cells. The compound induced cancer inhibition mainly through apoptosis and thus has a potential in cancer therapeutics.
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Affiliation(s)
- Saleem Farooq
- Bioorganic Chemistry Division, CSIR-Indian Institute of Integrative Medicine, Canal Road Jammu-180001, J&K, India.,Department of Chemistry, Government Degree College for Boys, Baramulla, 193101, J&K, India
| | - Javid A Banday
- Department of Chemistry, National Institute of Technology, Hazratbal, Srinagar-190006, J&K, India
| | - Aashiq Hussain
- Cancer Pharmacology Division, CSIR-Indian Institute of Integrative Medicine, Canal Road Jammu -180001, J&K, India
| | - Momina Nazir
- Department of Chemistry, Cluster University of Srinagar, Government College for Women, M.A Road, Srinagar, 190001, J&K, India
| | - Mushtaq A Qurishi
- Islamic University of Science & Technology, Department of Chemistry, Awantipora, J&K, India
| | - Abid Hamid
- Cancer Pharmacology Division, CSIR-Indian Institute of Integrative Medicine, Canal Road Jammu -180001, J&K, India.,Academy of Scientific & Innovative Research (AcSIR), 110020, New Delhi, India
| | - Surrinder Koul
- Bioorganic Chemistry Division, CSIR-Indian Institute of Integrative Medicine, Canal Road Jammu-180001, J&K, India
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25
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Anquetil T, Payrastre B, Gratacap MP, Viaud J. The lipid products of phosphoinositide 3-kinase isoforms in cancer and thrombosis. Cancer Metastasis Rev 2018; 37:477-489. [DOI: 10.1007/s10555-018-9735-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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26
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Araki K, Miyoshi Y. Mechanism of resistance to endocrine therapy in breast cancer: the important role of PI3K/Akt/mTOR in estrogen receptor-positive, HER2-negative breast cancer. Breast Cancer 2017; 25:392-401. [PMID: 29086897 DOI: 10.1007/s12282-017-0812-x] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 10/26/2017] [Indexed: 12/18/2022]
Abstract
Endocrine therapy is a crucial treatment for estrogen receptor-positive (ER+) breast cancer, with proven clinical benefits. However, adaptive mechanisms emerge in the tumor, causing resistance to endocrine therapy. A better understanding of resistance mechanisms is needed to overcome this problem and to develop new, precise treatment strategies. Accumulating genetic and cancer biological studies demonstrate the importance of understanding the PI3K/Akt/mTOR and CDK4/6/RB pathways in ER+ HER2- breast cancer. PIK3CA (which encodes phosphatidylinositol-4, 5-bisphosphate 3-kinase catalytic subunit α) is frequently mutated in breast cancer, and 30% of advanced ER+ HER2- breast cancers have an activating PIK3CA mutation. AKT1 mutations (E17K) have been found in 1.4-8% of breast cancer patients. ER+ breast cancer patients preferentially demonstrate gain of CCND1 (cyclin D1; 58% in luminal B vs. 29% in luminal A) and CDK4 (25% in luminal B vs. 14% in luminal A) and loss of CDKN2A (p16) and CDKN2C (p18), which are negatively regulated with the cell cycle and are correlated with the CDK4/6/RB pathway. Abnormalities in PI3K/Akt/mTOR and CDK4/6/RB pathways due to genetic alterations result in deregulated kinase activity and malignant transformation. This review focuses on the recent reports of the essential role of PI3K/Akt/mTOR and CDK4/6/RB pathways in ER+ HER2- breast cancer.
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Affiliation(s)
- Kazuhiro Araki
- Division of Breast and Endocrine, Department of Surgery, Cancer Center, Hyogo College of Medicine, 1-1 Mukogawa, Nishinomiya, Hyogo, 663-8501, Japan.
| | - Yasuo Miyoshi
- Division of Breast and Endocrine, Department of Surgery, Cancer Center, Hyogo College of Medicine, 1-1 Mukogawa, Nishinomiya, Hyogo, 663-8501, Japan
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27
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Li X, Chen W, Li P, Wei J, Cheng Y, Liu P, Yan Q, Xu X, Cui Y, Gu Z, Simoncini T, Fu X. Follicular Stimulating Hormone Accelerates Atherogenesis by Increasing Endothelial VCAM-1 Expression. Theranostics 2017; 7:4671-4688. [PMID: 29187895 PMCID: PMC5706091 DOI: 10.7150/thno.21216] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Accepted: 09/08/2017] [Indexed: 01/02/2023] Open
Abstract
Rationale: Postmenopausal atherosclerosis (AS) has for decades been attributed to estrogen deficiency. Although the follicular stimulating hormone (FSH) levels rise sharply in parallel, the direct effect of FSH on AS has never been investigated. In this study, we explored the possible role of FSH in the development of AS. Methods: This was a prospective cohort study of 48 healthy premenopausal and 15 postmenopausal women. ApoE knockout mice were used as atherosclerosis model and human umbilical vascular endothelial cells (HUVECs) were cultured as cell model. Serum hormones and vascular cell adhesion molecule-1 (VCAM-1) levels were measured. Real-time PCR, histology for atherosclerotic lesions, immunofluorescence, luciferase assay, transfection experiments, flow chamber adhesion assay and western blot were performed. Results: In ApoE knockout mice, administration of FSH increased the atherosclerotic lesions and serum VCAM-1 concentration. Importantly, in blood samples of postmenopausal women, we detected significantly higher levels of FSH and VCAM-1 compared with those from premenopausal women, and there was a positive correlation between these two molecules. In cultured HUVECs, FSH receptor (FSHR) mRNA and protein expression were detected and FSH enhanced VCAM-1 expression. This effect was mediated by the activation of nuclear factor κB (NF-κB), which was sequentially enhanced by the activation of PI3K/Akt/mTOR cascade. FSH first enhanced GαS activity resulting in elevated cAMP level and PKA activity, which relayed the signals from FSHR to the PI3K/Akt/mTOR cascade. Furthermore, FSHR was detected in endothelial caveolae fraction and interacted with caveolin-1 and GαS. The disruption of caveolae or the silencing of caveolin-1 blocked FSH effects on signaling activation and VCAM-1 expression, suggesting the existence of a functional signaling module in membrane caveolae. Finally, FSH increased human monocyte adhesion to HUVECs which was reversed by the VCAM-1 neutralizing antibody. Conclusion: FSHR was located in the membrane caveolae of HUVECs and FSH promoted VCAM-1 expression via FSHR/GαS /cAMP/PKA and PI3K/Akt/mTOR/NF-κB pathway. This may contribute to the deleterious role of FSH in the development of AS in postmenopausal women.
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28
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Estevez B, Du X. New Concepts and Mechanisms of Platelet Activation Signaling. Physiology (Bethesda) 2017; 32:162-177. [PMID: 28228483 DOI: 10.1152/physiol.00020.2016] [Citation(s) in RCA: 190] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Upon blood vessel injury, platelets are exposed to adhesive proteins in the vascular wall and soluble agonists, which initiate platelet activation, leading to formation of hemostatic thrombi. Pathological activation of platelets can induce occlusive thrombosis, resulting in ischemic events such as heart attack and stroke, which are leading causes of death globally. Platelet activation requires intracellular signal transduction initiated by platelet receptors for adhesion proteins and soluble agonists. Whereas many platelet activation signaling pathways have been established for many years, significant recent progress reveals much more complex and sophisticated signaling and amplification networks. With the discovery of new receptor signaling pathways and regulatory networks, some of the long-standing concepts of platelet signaling have been challenged. This review provides an overview of the new developments and concepts in platelet activation signaling.
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Affiliation(s)
- Brian Estevez
- Department of Pharmacology, University of Illinois at Chicago, Chicago, Illinois
| | - Xiaoping Du
- Department of Pharmacology, University of Illinois at Chicago, Chicago, Illinois
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29
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Yang X, Yang JA, Liu BH, Liao JM, Yuan FE, Tan YQ, Chen QX. TGX-221 inhibits proliferation and induces apoptosis in human glioblastoma cells. Oncol Rep 2017; 38:2836-2842. [PMID: 29048665 PMCID: PMC5780035 DOI: 10.3892/or.2017.5991] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 09/04/2017] [Indexed: 01/08/2023] Open
Abstract
Glioblastoma is the most common type of primary brain tumor in adults, with high mortality and morbidity rates. More effective therapeutic strategies are imperative. Previous studies have shown that the known p110-β-selective inhibitor TGX-221 blocks the activation of PKB/Akt in PTEN-deficient cells. We treated U87 and U251 glioblastoma cells with TGX-221 to determine the effect of TGX-221. We performed a Cell Counting Kit-8 (CCK-8) test, EDU staining and cell cycle distribution analysis and found that TGX-221 inhibited glioblastoma cell proliferation. Next, the effect of TGX-221 on cell apoptosis was investigated using flow cytometry. These results demonstrated that TGX-221 induced apoptosis in glioblastoma cells. Moreover, migration and invasion assays revealed that TGX-221 inhibited human glioblastoma cell migration and invasion. Collectively, our study revealed that TGX-221 could inhibit proliferation and induce apoptosis in glioblastoma cells.
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Affiliation(s)
- Xue Yang
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuchang, Wuhan, Hubei 430060, P.R. China
| | - Ji-An Yang
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuchang, Wuhan, Hubei 430060, P.R. China
| | - Bao-Hui Liu
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuchang, Wuhan, Hubei 430060, P.R. China
| | - Jian-Ming Liao
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuchang, Wuhan, Hubei 430060, P.R. China
| | - Fan-En Yuan
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuchang, Wuhan, Hubei 430060, P.R. China
| | - Yin-Qiu Tan
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuchang, Wuhan, Hubei 430060, P.R. China
| | - Qian-Xue Chen
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuchang, Wuhan, Hubei 430060, P.R. China
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30
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Law NC, White MF, Hunzicker-Dunn ME. G protein-coupled receptors (GPCRs) That Signal via Protein Kinase A (PKA) Cross-talk at Insulin Receptor Substrate 1 (IRS1) to Activate the phosphatidylinositol 3-kinase (PI3K)/AKT Pathway. J Biol Chem 2016; 291:27160-27169. [PMID: 27856640 DOI: 10.1074/jbc.m116.763235] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 11/14/2016] [Indexed: 12/11/2022] Open
Abstract
G protein-coupled receptors (GPCRs) activate PI3K/v-AKT thymoma viral oncoprotein (AKT) to regulate many cellular functions that promote cell survival, proliferation, and growth. However, the mechanism by which GPCRs activate PI3K/AKT remains poorly understood. We used ovarian preantral granulosa cells (GCs) to elucidate the mechanism by which the GPCR agonist FSH via PKA activates the PI3K/AKT cascade. Insulin-like growth factor 1 (IGF1) is secreted in an autocrine/paracrine manner by GCs and activates the IGF1 receptor (IGF1R) but, in the absence of FSH, fails to stimulate YXXM phosphorylation of IRS1 (insulin receptor substrate 1) required for PI3K/AKT activation. We show that PKA directly phosphorylates the protein phosphatase 1 (PP1) regulatory subunit myosin phosphatase targeting subunit 1 (MYPT1) to activate PP1 associated with the IGF1R-IRS1 complex. Activated PP1 is sufficient to dephosphorylate at least four IRS1 Ser residues, Ser318, Ser346, Ser612, and Ser789, and promotes IRS1 YXXM phosphorylation by the IGF1R to activate the PI3K/AKT cascade. Additional experiments indicate that this mechanism also occurs in breast cancer, thyroid, and preovulatory granulosa cells, suggesting that the PKA-dependent dephosphorylation of IRS1 Ser/Thr residues is a conserved mechanism by which GPCRs signal to activate the PI3K/AKT pathway downstream of the IGF1R.
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Affiliation(s)
- Nathan C Law
- From the School of Molecular Biosciences, Washington State University, Pullman, Washington 99164 and
| | - Morris F White
- the Division of Endocrinology, Dept. of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Mary E Hunzicker-Dunn
- From the School of Molecular Biosciences, Washington State University, Pullman, Washington 99164 and
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31
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Meng F, Wang F, Wang L, Wong SCC, Cho WCS, Chan LWC. MiR-30a-5p Overexpression May Overcome EGFR-Inhibitor Resistance through Regulating PI3K/AKT Signaling Pathway in Non-small Cell Lung Cancer Cell Lines. Front Genet 2016; 7:197. [PMID: 27895663 PMCID: PMC5108768 DOI: 10.3389/fgene.2016.00197] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 10/28/2016] [Indexed: 12/22/2022] Open
Abstract
Lung cancer is one of the most common deadly diseases worldwide, most of which is non-small cell lung cancer (NSCLC). The epidermal growth factor receptor (EGFR) mutant NSCLCs frequently respond to the EGFR tyrosine kinase inhibitors (EGFR-TKIs) treatment, such as Gefitinib and Erlotinib, but the development of acquired resistance limits the utility. Multiple resistance mechanisms have been explored, e.g., the activation of alternative tyrosine kinase receptors (TKRs) sharing similar downstream pathways to EGFR. MicroRNAs (miRNAs) are short, endogenous and non-coding RNA molecules, regulating the target gene expression. In this study, we explored the potential of miR-30a-5p in targeting the EGFR and insulin-like growth factor receptor-1 (IGF-1R) signaling pathways to overcome the drug resistance. IGF-1R is one of the tyrosine kinase receptors that share the same EGFR downstream molecules, including phosphatidylinositol 3 kinase (PI3K) and protein kinase B (AKT). In this work, an in vitro study was designed using EGFR inhibitor (Gefitinib), IGF-1R inhibitor (NVP-AEW541), and miRNA mimics in two Gefitinib-resistant NSCLC cell lines, H460 and H1975. We found that the combination of EGFR and IGF-1R inhibitors significantly decreased the phosphorylated AKT (p-AKT) expression levels compared to the control group in these two cell lines. Knockdown of phosphoinositide-3-kinase regulatory subunit 2 (PIK3R2) had the same effect with the dual inhibition of EGFR and IGF-1R to reduce the expression of p-AKT in the signaling pathway. Overexpression of miR-30a-5p significantly reduced the expression of the PI3K regulatory subunit (PIK3R2) to further induce cell apoptosis, and inhibit cell invasion and migration properties. Hence, miR-30a-5p may play vital roles in overcoming the acquired resistance to EGFR-TKIs, and provide useful information for establishing novel cancer treatment.
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Affiliation(s)
- Fei Meng
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University Hong Kong, China
| | - Fengfeng Wang
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University Hong Kong, China
| | - Lili Wang
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University Hong Kong, China
| | - S C Cesar Wong
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University Hong Kong, China
| | - William C S Cho
- Department of Clinical Oncology, Queen Elizabeth Hospital Hong Kong, China
| | - Lawrence W C Chan
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University Hong Kong, China
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32
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Singh P, Dar MS, Dar MJ. p110α and p110β isoforms of PI3K signaling: are they two sides of the same coin? FEBS Lett 2016; 590:3071-82. [PMID: 27552098 DOI: 10.1002/1873-3468.12377] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 08/20/2016] [Accepted: 08/22/2016] [Indexed: 12/30/2022]
Abstract
Class-1 phosphatidylinositol-3-kinases (PI3Ks) are activated by a variety of extracellular stimuli and have been implicated in a wide range of cellular processes. p110α and p110β are the two most studied isoforms of the class-1A PI3K signaling pathway. Although these two isoforms are ubiquitously expressed and play multiple redundant roles, they also have distinct functions within the cell. More recently, p110α and p110β isoforms have been shown to translocate into the nucleus and play a role in DNA replication and repair, and in cell cycle progression. In the following Review article, we discuss the overlapping and unique roles of p110α and p110β isoforms with a particular focus on their structure, expression analysis, subcellular localization, and signaling contributions in various cell types and model organisms.
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Affiliation(s)
- Paramjeet Singh
- Academy of Scientific and Innovative Research, New Delhi, India.,Cancer Pharmacology Division, CSIR-Indian Institute of Integrative Medicine, Jammu, India
| | - Mohd Saleem Dar
- Academy of Scientific and Innovative Research, New Delhi, India.,Cancer Pharmacology Division, CSIR-Indian Institute of Integrative Medicine, Jammu, India
| | - Mohd Jamal Dar
- Academy of Scientific and Innovative Research, New Delhi, India. .,Cancer Pharmacology Division, CSIR-Indian Institute of Integrative Medicine, Jammu, India.
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Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is a signalopathy of renal tubular epithelial cells caused by naturally occurring mutations in two distinct genes, polycystic kidney disease 1 (PKD1) and 2 (PKD2). Genetic variants in PKD1, which encodes the polycystin-1 (PC-1) protein, remain the predominant factor associated with the pathogenesis of nearly two-thirds of all patients diagnosed with PKD. Although the relationship between defective PC-1 with renal cystic disease initiation and progression remains to be fully elucidated, there are numerous clinical studies that have focused upon the control of effector systems involving heterotrimeric G protein regulation. A major regulator in the activation state of heterotrimeric G proteins are G protein-coupled receptors (GPCRs), which are defined by their seven transmembrane-spanning regions. PC-1 has been considered to function as an unconventional GPCR, but the mechanisms by which PC-1 controls signal processing, magnitude, or trafficking through heterotrimeric G proteins remains to be fully known. The diversity of heterotrimeric G protein signaling in PKD is further complicated by the presence of non-GPCR proteins in the membrane or cytoplasm that also modulate the functional state of heterotrimeric G proteins within the cell. Moreover, PC-1 abnormalities promote changes in hormonal systems that ultimately interact with distinct GPCRs in the kidney to potentially amplify or antagonize signaling output from PC-1. This review will focus upon the canonical and noncanonical signaling pathways that have been described in PKD with specific emphasis on which heterotrimeric G proteins are involved in the pathological reorganization of the tubular epithelial cell architecture to exacerbate renal cystogenic pathways.
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Affiliation(s)
- Taketsugu Hama
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Frank Park
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee
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Xiang RF, Stack D, Huston SM, Li SS, Ogbomo H, Kyei SK, Mody CH. Ras-related C3 Botulinum Toxin Substrate (Rac) and Src Family Kinases (SFK) Are Proximal and Essential for Phosphatidylinositol 3-Kinase (PI3K) Activation in Natural Killer (NK) Cell-mediated Direct Cytotoxicity against Cryptococcus neoformans. J Biol Chem 2016; 291:6912-22. [PMID: 26867574 PMCID: PMC4807276 DOI: 10.1074/jbc.m115.681544] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 01/13/2016] [Indexed: 11/06/2022] Open
Abstract
The activity of Rac in leukocytes is essential for immunity. However, its role in NK cell-mediated anti-microbial signaling remains unclear. In this study, we investigated the role of Rac in NK cell mediated anti-cryptococcal killing. We found thatCryptococcus neoformansindependently activates both Rac and SFK pathways in NK cells, and unlike in tumor killing,Cryptococcusinitiated a novel Rac → PI3K → Erk cytotoxicity cascade. Remarkably, Rac was not required for conjugate formation, despite its essential role in NK cytotoxicity againstC. neoformans Taken together, our data show that, unlike observations with tumor cells, NK cells use a novel Rac cytotoxicity pathway in conjunction with SFK, to killC. neoformans.
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Affiliation(s)
- Richard F Xiang
- From the Departments of Microbiology, Immunology and Infectious Diseases and the Snyder Institute for Chronic Disease, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Danuta Stack
- From the Departments of Microbiology, Immunology and Infectious Diseases and the Snyder Institute for Chronic Disease, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Shaunna M Huston
- From the Departments of Microbiology, Immunology and Infectious Diseases and the Snyder Institute for Chronic Disease, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Shu Shun Li
- From the Departments of Microbiology, Immunology and Infectious Diseases and the Snyder Institute for Chronic Disease, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Henry Ogbomo
- From the Departments of Microbiology, Immunology and Infectious Diseases and the Snyder Institute for Chronic Disease, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Stephen K Kyei
- From the Departments of Microbiology, Immunology and Infectious Diseases and the Snyder Institute for Chronic Disease, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Christopher H Mody
- From the Departments of Microbiology, Immunology and Infectious Diseases and the Snyder Institute for Chronic Disease, University of Calgary, Calgary, Alberta T2N 4N1, Canada Internal Medicine and
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35
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Khalil BD, Hsueh C, Cao Y, Abi Saab WF, Wang Y, Condeelis JS, Bresnick AR, Backer JM. GPCR Signaling Mediates Tumor Metastasis via PI3Kβ. Cancer Res 2016; 76:2944-53. [PMID: 27013201 DOI: 10.1158/0008-5472.can-15-1675] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 02/23/2016] [Indexed: 12/16/2022]
Abstract
Inappropriate activation of PI3K signaling has been implicated strongly in human cancer. Although studies on the role of PI3K signaling in breast tumorigenesis and progression have focused most intensively on PI3Kα, a role for PI3Kβ has begun to emerge. The PI3Kβ isoform is unique among class IA PI3K enzymes in that it is activated by both receptor tyrosine kinases and G-protein-coupled receptors (GPCR). In previous work, we identified a mutation that specifically abolishes PI3Kβ binding to Gβγ (p110(526KK-DD)). Expression of this mutant in p110β-silenced breast cancer cells inhibits multiple steps of the metastatic cascade in vitro and in vivo and causes a cell autonomous defect in invadopodial matrix degradation. Our results identify a novel link between GPCRs and PI3Kβ in mediating metastasis, suggesting that disruption of this link might offer a novel therapeutic target to prevent the development of metastatic disease. Cancer Res; 76(10); 2944-53. ©2016 AACR.
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Affiliation(s)
- Bassem D Khalil
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York
| | - Christine Hsueh
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York
| | - Yanyan Cao
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York
| | - Widian F Abi Saab
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York
| | - Yarong Wang
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York
| | - John S Condeelis
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York
| | - Anne R Bresnick
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York.
| | - Jonathan M Backer
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York. Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York.
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36
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Leyme A, Marivin A, Garcia-Marcos M. GIV/Girdin (Gα-interacting, Vesicle-associated Protein/Girdin) Creates a Positive Feedback Loop That Potentiates Outside-in Integrin Signaling in Cancer Cells. J Biol Chem 2016; 291:8269-82. [PMID: 26887938 DOI: 10.1074/jbc.m115.691550] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Indexed: 11/06/2022] Open
Abstract
Activation of the tyrosine kinase focal adhesion kinase (FAK) upon cell stimulation by the extracellular matrix initiates integrin outside-in signaling. FAK is directly recruited to active integrins, which enhances its kinase activity and triggers downstream signaling like activation of PI3K. We recently described that Gα-interacting, vesicle-associated protein (GIV), a protein up-regulated in metastatic cancers, is also required for outside-in integrin signaling. More specifically, we found that GIV is a non-receptor guanine nucleotide exchange factor that activates trimeric G proteins in response to integrin stimulation to enhance PI3K signaling and tumor cell migration. In contrast, previous reports have established that GIV is involved in phosphotyrosine (Tyr(P))-based signaling in response to growth factor stimulation;i.e.GIV phosphorylation at Tyr-1764 and Tyr-1798 recruits and activates PI3K. Here we show that phosphorylation of GIV at Tyr-1764/Tyr-1798 is also required to enhance PI3K-Akt signaling and tumor cell migration in response to integrin stimulation, indicating that GIV functions in Tyr(P)-dependent integrin signaling. Unexpectedly, we found that activation of FAK, an upstream component of the integrin Tyr(P) signaling cascade, was diminished in GIV-depleted cells, suggesting that GIV is required to establish a positive feedback loop that enhances integrin-FAK signaling. Mechanistically, we demonstrate that this feedback activation of FAK depends on both guanine nucleotide exchange factor and Tyr(P) GIV signaling as well as on their convergence point, PI3K. Taken together, our results provide novel mechanistic insights into how GIV promotes proinvasive cancer cell behavior by working as a signal-amplifying platform at the crossroads of trimeric G protein and Tyr(P) signaling.
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Affiliation(s)
- Anthony Leyme
- From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Arthur Marivin
- From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Mikel Garcia-Marcos
- From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
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Barrows D, Schoenfeld SM, Hodakoski C, Silkov A, Honig B, Couvillon A, Shymanets A, Nürnberg B, Asara JM, Parsons R. p21-activated Kinases (PAKs) Mediate the Phosphorylation of PREX2 Protein to Initiate Feedback Inhibition of Rac1 GTPase. J Biol Chem 2015; 290:28915-31. [PMID: 26438819 DOI: 10.1074/jbc.m115.668244] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Indexed: 11/06/2022] Open
Abstract
Phosphatidylinositol 3,4,5-trisphosphate (PIP3)-dependent Rac exchanger 2 (PREX2) is a guanine nucleotide exchange factor (GEF) for the Ras-related C3 botulinum toxin substrate 1 (Rac1) GTPase, facilitating the exchange of GDP for GTP on Rac1. GTP-bound Rac1 then activates its downstream effectors, including p21-activated kinases (PAKs). PREX2 and Rac1 are frequently mutated in cancer and have key roles within the insulin-signaling pathway. Rac1 can be inactivated by multiple mechanisms; however, negative regulation by insulin is not well understood. Here, we show that in response to being activated after insulin stimulation, Rac1 initiates its own inactivation by decreasing PREX2 GEF activity. Following PREX2-mediated activation of Rac1 by the second messengers PIP3 or Gβγ, we found that PREX2 was phosphorylated through a PAK-dependent mechanism. PAK-mediated phosphorylation of PREX2 reduced GEF activity toward Rac1 by inhibiting PREX2 binding to PIP3 and Gβγ. Cell fractionation experiments also revealed that phosphorylation prevented PREX2 from localizing to the cellular membrane. Furthermore, the onset of insulin-induced phosphorylation of PREX2 was delayed compared with AKT. Altogether, we propose that second messengers activate the Rac1 signal, which sets in motion a cascade whereby PAKs phosphorylate and negatively regulate PREX2 to decrease Rac1 activation. This type of regulation would allow for transient activation of the PREX2-Rac1 signal and may be relevant in multiple physiological processes, including diseases such as diabetes and cancer when insulin signaling is chronically activated.
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Affiliation(s)
- Douglas Barrows
- From the Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029, the Department of Pharmacology, Columbia University, New York, New York 10032
| | - Sarah M Schoenfeld
- From the Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Cindy Hodakoski
- From the Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Antonina Silkov
- the Department of Biochemistry and Molecular Biophysics, Howard Hughes Medical Institute, Columbia University, New York, New York 10032
| | - Barry Honig
- the Department of Biochemistry and Molecular Biophysics, Howard Hughes Medical Institute, Columbia University, New York, New York 10032
| | | | - Aliaksei Shymanets
- the Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Pharmaceutical Research, University of Tübingen, 72074 Tübingen, Germany
| | - Bernd Nürnberg
- the Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Pharmaceutical Research, University of Tübingen, 72074 Tübingen, Germany
| | - John M Asara
- the Division of Signal Transduction, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02115, and the Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115
| | - Ramon Parsons
- From the Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029,
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38
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Abstract
Phosphoinositide 3-kinases (PI3Ks) are central regulators of cellular responses to extracellular stimuli, and are involved in growth, proliferation, migration, and metabolism. The Class I PI3Ks are activated by Receptor Tyrosine Kinases (RTKs) or G Protein-Coupled Receptors (GPCRs), and their signaling is commonly deregulated in disease conditions. Among the class I PI3Ks, the p110β isoform is unique in being activated by both RTKs and GPCRs, and its ability to bind Rho-GTPases and Rab5. Recent studies have characterized these p110β interacting partners, defining the binding mechanisms and regulation, and thus provide insight into the function of this kinase in physiology and disease. This review summarizes the developments in p110β research, focusing on the interacting partners and their role in p110β-mediated signaling.
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Affiliation(s)
- Hashem A Dbouk
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390
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39
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Ballou LM, Lin RZ, Cohen IS. Control of cardiac repolarization by phosphoinositide 3-kinase signaling to ion channels. Circ Res 2015; 116:127-37. [PMID: 25552692 DOI: 10.1161/circresaha.116.303975] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Upregulation of phosphoinositide 3-kinase (PI3K) signaling is a common alteration in human cancer, and numerous drugs that target this pathway have been developed for cancer treatment. However, recent studies have implicated inhibition of the PI3K signaling pathway as the cause of a drug-induced long-QT syndrome in which alterations in several ion currents contribute to arrhythmogenic drug activity. Surprisingly, some drugs that were thought to induce long-QT syndrome by direct block of the rapid delayed rectifier (IKr) also seem to inhibit PI3K signaling, an effect that may contribute to their arrhythmogenicity. The importance of PI3K in regulating cardiac repolarization is underscored by evidence that QT interval prolongation in diabetes mellitus also may result from changes in multiple currents because of decreased insulin activation of PI3K in the heart. How PI3K signaling regulates ion channels to control the cardiac action potential is poorly understood. Hence, this review summarizes what is known about the effect of PI3K and its downstream effectors, including Akt, on sodium, potassium, and calcium currents in cardiac myocytes. We also refer to some studies in noncardiac cells that provide insight into potential mechanisms of ion channel regulation by this signaling pathway in the heart. Drug development and safety could be improved with a better understanding of the mechanisms by which PI3K regulates cardiac ion channels and the extent to which PI3K inhibition contributes to arrhythmogenic susceptibility.
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Affiliation(s)
- Lisa M Ballou
- From the Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, NY (L.M.B., R.Z.L., I.S.C.); and the Medical Service, Northport VA Medical Center, NY (R.Z.L.)
| | - Richard Z Lin
- From the Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, NY (L.M.B., R.Z.L., I.S.C.); and the Medical Service, Northport VA Medical Center, NY (R.Z.L.).
| | - Ira S Cohen
- From the Department of Physiology and Biophysics and the Institute for Molecular Cardiology, Stony Brook University, NY (L.M.B., R.Z.L., I.S.C.); and the Medical Service, Northport VA Medical Center, NY (R.Z.L.).
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40
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Thorpe LM, Yuzugullu H, Zhao JJ. PI3K in cancer: divergent roles of isoforms, modes of activation and therapeutic targeting. Nat Rev Cancer 2015; 15:7-24. [PMID: 25533673 PMCID: PMC4384662 DOI: 10.1038/nrc3860] [Citation(s) in RCA: 964] [Impact Index Per Article: 107.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Phosphatidylinositol 3-kinases (PI3Ks) are crucial coordinators of intracellular signalling in response to extracellular stimuli. Hyperactivation of PI3K signalling cascades is one of the most common events in human cancers. In this Review, we discuss recent advances in our knowledge of the roles of specific PI3K isoforms in normal and oncogenic signalling, the different ways in which PI3K can be upregulated, and the current state and future potential of targeting this pathway in the clinic.
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Affiliation(s)
- Lauren M. Thorpe
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
- Program in Virology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Haluk Yuzugullu
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Jean J. Zhao
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
- Correspondence to J.J.Z. by
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41
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Pemberton JG, Stafford JL, Chang JP. Ligand-selective signal transduction by two endogenous GnRH isoforms involves biased activation of the class I PI3K catalytic subunits p110β, p110γ, and p110δ in pituitary gonadotropes and somatotropes. Endocrinology 2015; 156:218-30. [PMID: 25343277 DOI: 10.1210/en.2014-1640] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
In goldfish, 2 endogenous GnRH isoforms, GnRH2 and GnRH3, are released at the pituitary and directly stimulate LH and GH release using the same population of GnRH receptors (GnRHRs) but with GnRH-specific transduction mechanisms. Previously, we have shown that phosphoinositide 3-kinases (PI3Ks) mediate GnRH2- and GnRH3-stimulated LH and GH release. Among the 3 classes of PI3Ks, class I PI3Ks are the best characterized and consist of 4 110-kDa catalytic isoforms (p110α, p110β, p110γ, and p110δ). Importantly, p110β and p110γ, but not p110α or p110δ, can be directly activated by the Gβγ heterodimer of Gαβγ protein complexes. In the present study, we examined the expression of class I PI3K isoforms and the effects of selective inhibitors of p110α, p110β, p110γ, and p110δ catalytic activity on basal, as well as acute, GnRH2- and GnRH3-stimulated LH and GH release responses using primary cultures of dispersed goldfish pituitary cells in column perifusion. Results demonstrate that p110γ and p110δ are involved in the control of basal LH and GH release, whereas p110α and p110β only regulate basal LH secretion. However, p110β and p110γ both participated in GnRH3- and GnRH2-stimulated GH release, whereas p110β and p110γ mediated GnRH2- and GnRH3-induced LH release responses, respectively. GnRH2- and GnRH3-stimulated LH release, as well as GnRH3-elicited GH release, also required p110δ. These results constitute the first evidence for the differential involvement of class I PI3K catalytic subunits in GnRH actions, in general, and suggest that GnRH2 and GnRH3 binding to GnRHRs can bias the activation of class I PI3K signaling to mediate hormone release responses in 2 distinct pituitary cell types. The involvement of both class IA and IB PI3Ks implicates Gβγ subunits, as well as other known regulators of class I PI3Ks, as important components of GnRHR-mediated responses that could influence GnRH-selective signaling in other cell types.
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Affiliation(s)
- Joshua G Pemberton
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada, T6G 2E9
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Perino A, Beretta M, Kilić A, Ghigo A, Carnevale D, Repetto IE, Braccini L, Longo D, Liebig-Gonglach M, Zaglia T, Iacobucci R, Mongillo M, Wetzker R, Bauer M, Aime S, Vercelli A, Lembo G, Pfeifer A, Hirsch E. Combined inhibition of PI3Kβ and PI3Kγ reduces fat mass by enhancing α-MSH-dependent sympathetic drive. Sci Signal 2014; 7:ra110. [PMID: 25406378 DOI: 10.1126/scisignal.2005485] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Obesity is defined as an abnormal increase in white adipose tissue and has become a major medical burden worldwide. Signals from the brain control not only appetite but also energy expenditure, both of which contribute to body weight. We showed that genetic or pharmacological inhibition of two phosphatidylinositol 3-kinases (PI3Kβ and PI3Kγ) in mice reduced fat mass by promoting increased energy expenditure. This effect was accompanied by stimulation of lipolysis and the acquisition of the energy-burning characteristics of brown adipocytes by white adipocytes, a process referred to as "browning." The browning of the white adipocytes involved increased norepinephrine release from the sympathetic nervous system. We found that PI3Kβ and PI3Kγ together promoted a negative feedback loop downstream of the melanocortin 4 receptor in the central nervous system, which controls appetite and energy expenditure in the periphery. Analysis of mice with drug-induced sympathetic denervation suggested that these kinases controlled the sympathetic drive in the brain. Administration of inhibitors of both PI3Kβ and PI3Kγ to mice by intracerebroventricular delivery induced a 10% reduction in fat mass as quickly as 10 days. These results suggest that combined inhibition of PI3Kβ and PI3Kγ might represent a promising treatment for obesity.
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Affiliation(s)
- Alessia Perino
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy.
| | - Martina Beretta
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy. Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, D-07747 Jena, Germany
| | - Ana Kilić
- Institute of Pharmacology and Toxicology, University of Bonn, 53127 Bonn, Germany
| | - Alessandra Ghigo
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy
| | - Daniela Carnevale
- Department of Molecular Medicine, "Sapienza" University of Rome, 00161 Rome, Italy. Department of Angiocardioneurology and Translational Medicine, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Neuromed, 86077 Pozzilli (IS), Italy
| | - Ivan Enrico Repetto
- Neuroscience Institute Cavalieri Ottolenghi, Department of Neuroscience, University of Turin, 10043 Turin, Italy
| | - Laura Braccini
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy
| | - Dario Longo
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy
| | | | - Tania Zaglia
- Venetian Institute of Molecular Medicine, University of Padova, 35129 Padova, Italy
| | - Roberta Iacobucci
- Department of Angiocardioneurology and Translational Medicine, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Neuromed, 86077 Pozzilli (IS), Italy
| | - Marco Mongillo
- Department of Biomedical Sciences and Venetian Institute of Molecular Medicine, University of Padova, 35121 Padova, Italy
| | - Reinhard Wetzker
- Department of Molecular Cell Biology, Jena University Hospital, Friedrich Schiller University, 07745 Jena, Germany
| | - Michael Bauer
- Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, D-07747 Jena, Germany
| | - Silvio Aime
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy
| | - Alessandro Vercelli
- Neuroscience Institute Cavalieri Ottolenghi, Department of Neuroscience, University of Turin, 10043 Turin, Italy
| | - Giuseppe Lembo
- Department of Molecular Medicine, "Sapienza" University of Rome, 00161 Rome, Italy. Department of Angiocardioneurology and Translational Medicine, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Neuromed, 86077 Pozzilli (IS), Italy
| | - Alexander Pfeifer
- Institute of Pharmacology and Toxicology, University of Bonn, 53127 Bonn, Germany.
| | - Emilio Hirsch
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy.
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43
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Phosphoinositide 3-kinase β mediates microvascular endothelial repair of thrombotic microangiopathy. Blood 2014; 124:2142-9. [DOI: 10.1182/blood-2014-02-557975] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Key Points
Endothelial PI3Kβ is not required in the quiescent vasculature, but PI3Kβ loss confers sensitivity for thrombotic microangiopathy. PI3Kβ activity is required for endothelial angiogenic differentiation and microvascular repair.
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44
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Farooq S, Shakeel-u-Rehman, Hussain A, Hamid A, Qurishi MA, Koul S. Click chemistry inspired synthesis and bioevaluation of novel triazolyl derivatives of osthol as potent cytotoxic agents. Eur J Med Chem 2014; 84:545-54. [PMID: 25062005 DOI: 10.1016/j.ejmech.2014.07.069] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 07/17/2014] [Accepted: 07/19/2014] [Indexed: 11/30/2022]
Abstract
A new series of diverse triazoles linked through the hydroxyl group of lactone ring opened osthol (1) were synthesized using click chemistry approach. All the derivatives were subjected to 3-(4,5-Dimethylthiazol-yl)-diphenyl tetrazoliumbromide (MTT) cytotoxicity screening against a panel of seven different human cancer cell lines viz. colon (colo-205), colon (HCT-116), breast (T47D), lung (NCI-H322), lung (A549), prostate (PC-3) and Skin (A-431) to check their cytotoxic potential. Interestingly, among the tested molecules, most of the analogs displayed better cytotoxic activity than the parent osthol (1). Of the synthesized triazoles, compounds 8 showed the best activity with IC50 of 1.3, 4.9, 3.6, 41.0, 35.2, 26.4 and 7.2 μM against colon (Colo-205 and HCT-116), breast (T47D), lung (NCI-H322 and A549), prostate (PC-3) and Skin (A-431) cancer lines respectively. Compound 8 induced potent apoptotic effects in Colo-205 cells. The population of apoptotic cells increased from 11.4% in case of negative control to 24.1% at 25 μM of 8. Compound 8 also induced a remarkable decrease in mitochondrial membrane potential (ΛΨm) leading to apoptosis of cancer cells used. The present study resulted in identification of broad spectrum cytotoxic activity of analogs bearing electron withdrawing substituents, besides the enhanced selective activity of analogs with electron donating moieties.
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Affiliation(s)
- Saleem Farooq
- Bioorganic Chemistry Division, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu 180001, India.
| | - Shakeel-u-Rehman
- Bioorganic Chemistry Division, CSIR-Indian Institute of Integrative Medicine, Sanatnagar, Srinagar 190005, India
| | - Aashiq Hussain
- Cancer Pharmacology Division, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu 180001, India
| | - Abid Hamid
- Cancer Pharmacology Division, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu 180001, India
| | - Mushtaq A Qurishi
- Department of Chemistry, University of Kashmir, Srinagar 190006, India
| | - Surrinder Koul
- Bioorganic Chemistry Division, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu 180001, India.
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Molecular mechanisms of HPV induced carcinogenesis in head and neck. Oral Oncol 2014; 50:356-63. [DOI: 10.1016/j.oraloncology.2013.07.011] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 05/30/2013] [Accepted: 07/22/2013] [Indexed: 02/03/2023]
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Kang BH, Shim YJ, Tae YK, Song JA, Choi BK, Park IS, Min BH. Clusterin stimulates the chemotactic migration of macrophages through a pertussis toxin sensitive G-protein-coupled receptor and Gβγ-dependent pathways. Biochem Biophys Res Commun 2014; 445:645-50. [PMID: 24569077 DOI: 10.1016/j.bbrc.2014.02.071] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 02/15/2014] [Indexed: 10/25/2022]
Abstract
Clusterin induces the expression of various chemotactic cytokines including tumor necrosis factor-α (TNF-α) in macrophages and is involved in the cell migration. According to the results of this study, clusterin induced the directional migration (chemotaxis) of macrophages based on a checkerboard analysis. The chemotactic activity of clusterin was prevented by pretreatment with pertussis toxin (PTX), indicating that the Gαi/o-protein coupled receptor (GPCR) was involved in the chemotactic response of clusterin. Clusterin-stimulated chemotaxis was abrogated in a dose-dependent manner by pretreatment with gallein (a Gβγ inhibitor), indicating the involvement of Gβγ released from the GPCR. In addition, inhibitors of phospholipase C (PLC, U73122) and phosphoinositide 3-kinase (PI3K, LY294002), the key targets of Gβγ binding and activation, suppressed chemotactic migration by clusterin. The phosphorylation of Akt induced by clusterin was blocked by pretreatment with gallein or LY294002 but not with U73122, indicating that Gβγ released from the PTX-sensitive Gi protein complex activated PLC and PI3K/Akt signaling pathways separately. The activation of cellular MAP kinases was essential in that their inhibitors blocked clusterin-induced chemotaxis, and Gβγ was required for the activation of MAP kinases because gallein reduced their phosphorylations induced by clusterin. In addition, the inflammation-induced migration of macrophages was greatly reduced in clusterin-deficient mice based on a thioglycollate-induced peritonitis model system. These results suggest that clusterin stimulates the chemotactic migration of macrophages through a PTX-sensitive GPCR and Gβγ-dependent pathways and describe a novel role of clusterin as a chemoattractant of monocytes/macrophages, suggesting that clusterin may serve as a molecular bridge between inflammation and its remodeling of related tissue by recruiting immune cells.
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Affiliation(s)
- Byeong-Ho Kang
- Department of Pharmacology, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Young-Jun Shim
- Department of Pharmacology, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Yoo-Keung Tae
- Department of Pharmacology, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Jin-A Song
- Department of Pharmacology, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Byong-Kwan Choi
- Department of Internal Medicine, College of Medicine, Dongguk University Ilsan Hospital, Republic of Korea
| | - In-Sun Park
- Department of Anatomy, College of Medicine, Inha University, Republic of Korea
| | - Bon-Hong Min
- Department of Pharmacology, College of Medicine, Korea University, Seoul, Republic of Korea.
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Gross C, Bassell GJ. Neuron-specific regulation of class I PI3K catalytic subunits and their dysfunction in brain disorders. Front Mol Neurosci 2014; 7:12. [PMID: 24592210 PMCID: PMC3923137 DOI: 10.3389/fnmol.2014.00012] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 01/28/2014] [Indexed: 11/13/2022] Open
Abstract
The phosphoinositide 3-kinase (PI3K) complex plays important roles in virtually all cells of the body. The enzymatic activity of PI3K to phosphorylate phosphoinositides in the membrane is mediated by a group of catalytic and regulatory subunits. Among those, the class I catalytic subunits, p110α, p110β, p110γ, and p110δ, have recently drawn attention in the neuroscience field due to their specific dysregulation in diverse brain disorders. While in non-neuronal cells these catalytic subunits may have partially redundant functions, there is increasing evidence that in neurons their roles are more specialized, and confined to distinct receptor-dependent pathways. This review will summarize the emerging role of class I PI3K catalytic subunits in neurotransmitter-regulated neuronal signaling, and their dysfunction in a variety of neurological diseases, including fragile X syndrome, schizophrenia, and epilepsy. We will discuss recent literature describing the use of PI3K subunit-selective inhibitors to rescue brain disease-associated phenotypes in in vitro and animal models. These studies give rise to the exciting prospect that these drugs, originally designed for cancer treatment, may be repurposed as therapeutic drugs for brain disorders in the future.
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Affiliation(s)
- Christina Gross
- Department of Cell Biology, Emory University School of Medicine Atlanta, GA, USA ; Center for Translational Social Neuroscience, Emory University School of Medicine Atlanta, GA, USA
| | - Gary J Bassell
- Department of Cell Biology, Emory University School of Medicine Atlanta, GA, USA ; Center for Translational Social Neuroscience, Emory University School of Medicine Atlanta, GA, USA ; Department of Neurology, Emory University School of Medicine Atlanta, GA, USA
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Williams JW, Yau D, Sethakorn N, Kach J, Reed EB, Moore TV, Cannon J, Jin X, Xing H, Muslin AJ, Sperling AI, Dulin NO. RGS3 controls T lymphocyte migration in a model of Th2-mediated airway inflammation. Am J Physiol Lung Cell Mol Physiol 2013; 305:L693-701. [PMID: 24077945 DOI: 10.1152/ajplung.00214.2013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
T cell migration toward sites of antigen exposure is mediated by G protein signaling and is a key function in the development of immune responses. Regulators of G protein signaling (RGS) proteins modulate G protein signaling; however, their role in the regulation of adaptive immune responses has not been thoroughly explored. Herein we demonstrated abundant expression of the Gi/Gq-specific RGS3 in activated T cells, and that diminished RGS3 expression in a T cell thymoma increased cytokine-induced migration. To examine the role of endogenous RGS3 in vivo, mice deficient in the RGS domain (RGS3(ΔRGS)) were generated and tested in an experimental model of asthma. Compared with littermate controls, the inflammation in the RGS3(ΔRGS) mice was characterized by increased T cell numbers and the striking development of perivascular lymphoid structures. Surprisingly, while innate inflammatory cells were also increased in the lungs of RGS3(ΔRGS) mice, eosinophil numbers and Th2 cytokine production were equivalent to control mice. In contrast, T cell numbers in the draining lymph nodes (dLN) were reduced in the RGS3(ΔRGS), demonstrating a redistribution of T cells from the dLN to the lungs via increased RGS3(ΔRGS) T cell migration. Together these novel findings show a nonredundant role for endogenous RGS3 in controlling T cell migration in vitro and in an in vivo model of inflammation.
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Affiliation(s)
- Jesse W Williams
- Section of Pulmonary and Critical Care, Dept. of Medicine, The Univ. of Chicago, 5841 S. Maryland Ave., MC6076, Rm. M-648, Chicago, IL 60637.
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Shymanets A, Prajwal, Bucher K, Beer-Hammer S, Harteneck C, Nürnberg B. p87 and p101 subunits are distinct regulators determining class IB phosphoinositide 3-kinase (PI3K) specificity. J Biol Chem 2013; 288:31059-68. [PMID: 24014027 DOI: 10.1074/jbc.m113.508234] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Class IB phosphoinositide 3-kinase γ (PI3Kγ) comprises a single catalytic p110γ subunit, which binds to two non-catalytic subunits, p87 or p101, and controls a plethora of fundamental cellular responses. The non-catalytic subunits are assumed to be redundant adaptors for Gβγ enabling G-protein-coupled receptor-mediated regulation of PI3Kγ. Growing experimental data provide contradictory evidence. To elucidate the roles of the non-catalytic subunits in determining the specificity of PI3Kγ, we tested the impact of p87 and p101 in heterodimeric p87-p110γ and p101-p110γ complexes on the modulation of PI3Kγ activity in vitro and in living cells. RT-PCR, biochemical, and imaging data provide four lines of evidence: (i) specific expression patterns of p87 and p101, (ii) up-regulation of p101, providing the basis to consider p87 as a protein forming a constitutively and p101 as a protein forming an inducibly expressed PI3Kγ, (iii) differences in basal and stimulated enzymatic activities, and (iv) differences in complex stability, all indicating apparent diversity within class IB PI3Kγ. In conclusion, expression and activities of PI3Kγ are modified differently by p87 and p101 in vitro and in living cells, arguing for specific regulatory roles of the non-catalytic subunits in the differentiation of PI3Kγ signaling pathways.
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Affiliation(s)
- Aliaksei Shymanets
- From the Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics and Interfaculty Centre of Pharmacogenomics and Pharmaceutical Research, University of Tübingen, 72074 Tübingen, Germany
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Abstract
Phosphoinositides (PIs) make up only a small fraction of cellular phospholipids, yet they control almost all aspects of a cell's life and death. These lipids gained tremendous research interest as plasma membrane signaling molecules when discovered in the 1970s and 1980s. Research in the last 15 years has added a wide range of biological processes regulated by PIs, turning these lipids into one of the most universal signaling entities in eukaryotic cells. PIs control organelle biology by regulating vesicular trafficking, but they also modulate lipid distribution and metabolism via their close relationship with lipid transfer proteins. PIs regulate ion channels, pumps, and transporters and control both endocytic and exocytic processes. The nuclear phosphoinositides have grown from being an epiphenomenon to a research area of its own. As expected from such pleiotropic regulators, derangements of phosphoinositide metabolism are responsible for a number of human diseases ranging from rare genetic disorders to the most common ones such as cancer, obesity, and diabetes. Moreover, it is increasingly evident that a number of infectious agents hijack the PI regulatory systems of host cells for their intracellular movements, replication, and assembly. As a result, PI converting enzymes began to be noticed by pharmaceutical companies as potential therapeutic targets. This review is an attempt to give an overview of this enormous research field focusing on major developments in diverse areas of basic science linked to cellular physiology and disease.
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Affiliation(s)
- Tamas Balla
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
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