201
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Yang Y, Kong W, Xia Z, Xiao L, Wang S. Regulation mechanism of PDK1 on macrophage metabolism and function. Cell Biochem Funct 2016; 34:546-553. [DOI: 10.1002/cbf.3235] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 09/11/2016] [Accepted: 10/11/2016] [Indexed: 01/21/2023]
Affiliation(s)
- Yueqin Yang
- Exercise Intervention and Health Promotion Hubei Province Synergy Innovation Center; Wuhan Sports University; Wuhan Hubei China
| | - Weiwei Kong
- Graduate School; Wuhan Sports University; Wuhan Hubei China
| | - Zhi Xia
- Exercise Physiology and Biochemical Laboratory, College of Physical Education; Jinggangshan University; Ji'an Jiangxi China
| | - Lin Xiao
- School of Physical Education and Health Science; Zhaoqing University; Zhaoqing Guangdong China
| | - Song Wang
- Exercise Intervention and Health Promotion Hubei Province Synergy Innovation Center; Wuhan Sports University; Wuhan Hubei China
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202
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Tong J, Zhang H, Sun D, Wang Y, Yang C, Liu Y. Over-expression of PTEN on proliferation and apoptosis in canine mammary tumors cells. Anim Cells Syst (Seoul) 2016. [DOI: 10.1080/19768354.2016.1256833] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
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203
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Decoding the Interactions Regulating the Active State Mechanics of Eukaryotic Protein Kinases. PLoS Biol 2016; 14:e2000127. [PMID: 27902690 PMCID: PMC5130182 DOI: 10.1371/journal.pbio.2000127] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Accepted: 10/24/2016] [Indexed: 02/07/2023] Open
Abstract
Eukaryotic protein kinases regulate most cellular functions by phosphorylating targeted protein substrates through a highly conserved catalytic core. In the active state, the catalytic core oscillates between open, intermediate, and closed conformations. Currently, the intramolecular interactions that regulate the active state mechanics are not well understood. Here, using cAMP-dependent protein kinase as a representative model coupled with biochemical, biophysical, and computational techniques, we define a set of highly conserved electrostatic and hydrophobic interactions working harmoniously to regulate these mechanics. These include the previously identified salt bridge between a lysine from the β3-strand and a glutamate from the αC-helix as well as an electrostatic interaction between the phosphorylated activation loop and αC-helix and an ensemble of hydrophobic residues of the Regulatory spine and Shell. Moreover, for over three decades it was thought that the highly conserved β3-lysine was essential for phosphoryl transfer, but our findings show that the β3-lysine is not required for phosphoryl transfer but is essential for the active state mechanics. Eukaryotic protein kinases (EPKs) regulate over a third of the human proteome by transferring the γ-phosphate from adenosine triphosphate (ATP) to a protein substrate in a process known as protein phosphorylation. Biochemical and biophysical studies have shown that EPKs undergo multiconformational rearrangements in which the catalytic core is oscillating between open, intermediate, and closed conformations when active. Presently, the intramolecular interactions that regulate this dynamic process are not well understood. In this paper, we show how a set of conserved electrostatic and hydrophobic interactions harmoniously regulate the active state mechanics. The electrostatic interactions involve the highly conserved salt bridge between the lysine from subdomain-II and glutamate from subdomain-III as well as an interaction between the activation loop and αC-helix. The hydrophobic interactions include the nonlinear motifs known as the Regulatory spine and Shell that traverse both lobes of the catalytic core. Furthermore, our findings show that the highly conserved “catalytic lysine” is not directly required for phosphoryl transfer but rather serves as a hub that aligns and positions the dynamic core elements required for catalysis.
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204
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Sun C, Sun Y, Jiang D, Bao G, Zhu X, Xu D, Wang Y, Cui Z. PDK1 promotes the inflammatory progress of fibroblast-like synoviocytes by phosphorylating RSK2. Cell Immunol 2016; 315:27-33. [PMID: 28314444 DOI: 10.1016/j.cellimm.2016.10.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 10/12/2016] [Accepted: 10/30/2016] [Indexed: 12/12/2022]
Abstract
This study investigated the role of PDK1 in inflammatory response which is initiated by TNF-α and analyzed the association between PDK1 and RSK2. TNF-α were added into MH7A cells to induce inflammation condition. Through overexpressing or suppressing PDK1 in MH7A cells, the role of PDK1 in cell invasiveness and inflammatory factors was determined. Levels of MMPs protein and inflammatory cytokines were assessed with PDK1 siRNA and TNF-α treatment. Inhibition of RSK2 was used to investigate the function of RSK2 on PDK1-induced inflammation. The phosphorylation of RSK2 was detected when PDK1 was inhibited. Luciferase reporter assay was performed to detect the transcriptional activity of NF-κB. We found highly expressed PDK1 could promote cell invasion and secretion of IL-1β and IL-6 in MH7A cells. Inhibition of RSK2 reduced the PDK1-induced cell invasion and cytokines secretion in MH7A cells. In response to TNF-α, PDK1 could phosphorylate RSK2 and activated RSK2, then promoting the activation of NF-κB. This may be a possible therapeutic option of rheumatoid arthritis.
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Affiliation(s)
- Chi Sun
- Department of Orthopedics, Affiliated Hospital of Nantong University, Nantong, Nantong 226001, People's Republic of China
| | - Yu Sun
- Department of Spine Surgery, the Second Affiliated Hospital of Nantong University, Nantong 226001, People's Republic of China
| | - Dingjun Jiang
- Department of Orthopedics, Affiliated Hospital of Nantong University, Nantong, Nantong 226001, People's Republic of China
| | - Guofeng Bao
- Department of Spine Surgery, the Second Affiliated Hospital of Nantong University, Nantong 226001, People's Republic of China
| | - Xinhui Zhu
- Department of Spine Surgery, the Second Affiliated Hospital of Nantong University, Nantong 226001, People's Republic of China
| | - Dawei Xu
- Department of Spine Surgery, the Second Affiliated Hospital of Nantong University, Nantong 226001, People's Republic of China
| | - Youhua Wang
- Department of Orthopedics, Affiliated Hospital of Nantong University, Nantong, Nantong 226001, People's Republic of China.
| | - Zhiming Cui
- Department of Spine Surgery, the Second Affiliated Hospital of Nantong University, Nantong 226001, People's Republic of China.
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205
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Quantitative assessment of kinase selectivity based the water-ring network in protein binding sites using molecular dynamics simulations. J Mol Liq 2016. [DOI: 10.1016/j.molliq.2016.06.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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206
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Budzko L, Marcinkowska-Swojak M, Jackowiak P, Kozlowski P, Figlerowicz M. Copy number variation of genes involved in the hepatitis C virus-human interactome. Sci Rep 2016; 6:31340. [PMID: 27510840 PMCID: PMC4980658 DOI: 10.1038/srep31340] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 07/18/2016] [Indexed: 02/06/2023] Open
Abstract
Copy number variation (CNV) is a newly discovered form of intra-species genetic polymorphism that is defined as deletions or duplications of genome segments ranging from 1 kbp to several Mbp. CNV accounts for the majority of the genetic variation observed in humans (CNV regions cover more than 10% of the human genome); therefore, it may significantly influence both the phenotype and susceptibility to various diseases. Unfortunately, the impact of CNV on a number of diseases, including hepatitis C virus (HCV) infection, remains largely unexplored. Here, we analyzed 421 human genes encoding proteins that have been shown to interact with HCV proteins or genomic RNA (proteins from the HCV-human interactome). We found that 19 of the 421 candidate genes are located in putative CNV regions. For all of these genes, copy numbers were determined for European, Asiatic and African populations using the multiplex ligation-dependent amplification (MLPA) method. As a result, we identified 4 genes, IGLL1, MLLT4, PDPK1, PPP1R13L, for which the CN-genotype ranged from 1 to 6. All of these genes are involved in host-virus interaction; thus, their polymorphism has a potential impact on the development of HCV infection and/or therapy outcome.
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Affiliation(s)
- Lucyna Budzko
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | | | - Paulina Jackowiak
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
- Institute of Chemical Technology and Engineering, Poznan University of Technology, Poznan, Poland
| | - Piotr Kozlowski
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
- Institute of Chemical Technology and Engineering, Poznan University of Technology, Poznan, Poland
| | - Marek Figlerowicz
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
- Institute of Computing Science, Poznan University of Technology, Poznan, Poland
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207
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Wei H, Li Y, Han S, Liu S, Zhang N, Zhao L, Li S, Li J. cPKCγ-Modulated Autophagy in Neurons Alleviates Ischemic Injury in Brain of Mice with Ischemic Stroke Through Akt-mTOR Pathway. Transl Stroke Res 2016; 7:497-511. [PMID: 27510769 DOI: 10.1007/s12975-016-0484-4] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 07/13/2016] [Accepted: 07/14/2016] [Indexed: 12/21/2022]
Abstract
We have reported that neuron-specific conventional protein kinase C (cPKC)γ is involved in the development of cerebral hypoxic preconditioning (HPC) and the neuroprotection against ischemic injuries, but its molecular mechanism is unclear. In this study, the adult and postnatal 24 h C57BL/6J wild-type (cPKCγ+/+) and cPKCγ knockout (cPKCγ-/-) mice were respectively used to establish the models of middle cerebral artery occlusion (MCAO)-induced ischemic stroke in vivo and oxygen-glucose deprivation (OGD)-treated primarily cultured cortical neurons as cell ischemia in vitro. The results showed that cPKCγ knockout could increase the infarct volume and neuronal cell loss in the peri-infarct region, and enhance the neurological deficits, the impaired coordination, and the reduced muscle strength of mice following 1 h MCAO/1-7 days reperfusion. Meanwhile, cPKCγ knockout significantly increased the conversion of LC3-I to LC3-II and beclin-1 protein expression, and resulted in more reductions in P-Akt, P-mTOR, and P-S6 phosphorylation levels in the peri-infarct region of mice with ischemic stroke. The autophagy inhibitor BafA1 could enhance or reduce neuronal cell loss in the peri-infarct region of cPKCγ+/+ and cPKCγ-/- mice after ischemic stroke. In addition, cPKCγ knockout and restoration could aggravate or alleviate OGD-induced neuronal ischemic injury in vitro through Akt-mTOR pathway-mediated autophagy. These results suggested that cPKCγ-modulated neuron-specific autophagy improves the neurological outcome of mice following ischemic stroke through the Akt-mTOR pathway, providing a potential therapeutic target for ischemic stroke.
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Affiliation(s)
- Haiping Wei
- Department of Neurobiology and Center of Stroke, Beijing Institute for Brain Disorders, Capital Medical University, #10 You An Men Wai Xi Tou Tiao, Beijing, 100069, People's Republic of China
| | - Yun Li
- Department of Neurobiology and Center of Stroke, Beijing Institute for Brain Disorders, Capital Medical University, #10 You An Men Wai Xi Tou Tiao, Beijing, 100069, People's Republic of China
| | - Song Han
- Department of Neurobiology and Center of Stroke, Beijing Institute for Brain Disorders, Capital Medical University, #10 You An Men Wai Xi Tou Tiao, Beijing, 100069, People's Republic of China
| | - Shuiqiao Liu
- Department of Neurobiology and Center of Stroke, Beijing Institute for Brain Disorders, Capital Medical University, #10 You An Men Wai Xi Tou Tiao, Beijing, 100069, People's Republic of China
| | - Nan Zhang
- Department of Neurobiology and Center of Stroke, Beijing Institute for Brain Disorders, Capital Medical University, #10 You An Men Wai Xi Tou Tiao, Beijing, 100069, People's Republic of China
| | - Li Zhao
- Department of Neurobiology and Center of Stroke, Beijing Institute for Brain Disorders, Capital Medical University, #10 You An Men Wai Xi Tou Tiao, Beijing, 100069, People's Republic of China
| | - Shujuan Li
- Department of Neurology, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, 100020, People's Republic of China.
| | - Junfa Li
- Department of Neurobiology and Center of Stroke, Beijing Institute for Brain Disorders, Capital Medical University, #10 You An Men Wai Xi Tou Tiao, Beijing, 100069, People's Republic of China.
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208
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Lian S, Shao Y, Liu H, He J, Lu W, Zhang Y, Jiang Y, Zhu J. PDK1 induces JunB, EMT, cell migration and invasion in human gallbladder cancer. Oncotarget 2016. [PMID: 26318166 DOI: 10.18632/oncotarget.49314931] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The protein 3-phosphoinositide-dependent protein kinase 1 (PDK1) is upregulated in cancer. Here we showed that PDK1 stimulated cell proliferation, invasion and metastasis in gallbladder cancer (GBC), by inducing JunB and epithelial-mesenchymal transition. JunB levels were increased in GBC samples and positively correlated with PDK1 levels in tumors. High levels of JunB predicted poor overall survival in GBC patients. Thus, PDK1 functions as a tumor promoter in human GBC by upregulating JunB.
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Affiliation(s)
- Shixian Lian
- Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Yebo Shao
- Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Houbao Liu
- Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Junyi He
- Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Weiqi Lu
- Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Yong Zhang
- Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Ying Jiang
- Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Jun Zhu
- Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai 200032, China
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209
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PDK1 induces JunB, EMT, cell migration and invasion in human gallbladder cancer. Oncotarget 2016; 6:29076-86. [PMID: 26318166 PMCID: PMC4745712 DOI: 10.18632/oncotarget.4931] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 07/23/2015] [Indexed: 12/31/2022] Open
Abstract
The protein 3-phosphoinositide-dependent protein kinase 1 (PDK1) is upregulated in cancer. Here we showed that PDK1 stimulated cell proliferation, invasion and metastasis in gallbladder cancer (GBC), by inducing JunB and epithelial–mesenchymal transition. JunB levels were increased in GBC samples and positively correlated with PDK1 levels in tumors. High levels of JunB predicted poor overall survival in GBC patients. Thus, PDK1 functions as a tumor promoter in human GBC by upregulating JunB.
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210
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Bago R, Sommer E, Castel P, Crafter C, Bailey FP, Shpiro N, Baselga J, Cross D, Eyers PA, Alessi DR. The hVps34-SGK3 pathway alleviates sustained PI3K/Akt inhibition by stimulating mTORC1 and tumour growth. EMBO J 2016; 35:1902-22. [PMID: 27481935 PMCID: PMC5007552 DOI: 10.15252/embj.201693929] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 07/04/2016] [Indexed: 12/16/2022] Open
Abstract
We explore mechanisms that enable cancer cells to tolerate PI3K or Akt inhibitors. Prolonged treatment of breast cancer cells with PI3K or Akt inhibitors leads to increased expression and activation of a kinase termed SGK3 that is related to Akt. Under these conditions, SGK3 is controlled by hVps34 that generates PtdIns(3)P, which binds to the PX domain of SGK3 promoting phosphorylation and activation by its upstream PDK1 activator. Furthermore, under conditions of prolonged PI3K/Akt pathway inhibition, SGK3 substitutes for Akt by phosphorylating TSC2 to activate mTORC1. We characterise 14h, a compound that inhibits both SGK3 activity and activation in vivo, and show that a combination of Akt and SGK inhibitors induced marked regression of BT‐474 breast cancer cell‐derived tumours in a xenograft model. Finally, we present the kinome‐wide analysis of mRNA expression dynamics induced by PI3K/Akt inhibition. Our findings highlight the importance of the hVps34‐SGK3 pathway and suggest it represents a mechanism to counteract inhibition of PI3K/Akt signalling. The data support the potential of targeting both Akt and SGK as a cancer therapeutic.
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Affiliation(s)
- Ruzica Bago
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences University of Dundee, Dundee, UK
| | - Eeva Sommer
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences University of Dundee, Dundee, UK
| | - Pau Castel
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Claire Crafter
- Oncology iMED, AstraZeneca CRUK Cambridge Institute, Cambridge, UK
| | - Fiona P Bailey
- Department of Biochemistry, Institute of Integrative Biology University of Liverpool, Liverpool, UK
| | - Natalia Shpiro
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences University of Dundee, Dundee, UK
| | - José Baselga
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Darren Cross
- Oncology iMED, AstraZeneca CRUK Cambridge Institute, Cambridge, UK
| | - Patrick A Eyers
- Department of Biochemistry, Institute of Integrative Biology University of Liverpool, Liverpool, UK
| | - Dario R Alessi
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences University of Dundee, Dundee, UK
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211
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Nuñez I, Rodriguez Pino M, Wiley DJ, Das ME, Chen C, Goshima T, Kume K, Hirata D, Toda T, Verde F. Spatial control of translation repression and polarized growth by conserved NDR kinase Orb6 and RNA-binding protein Sts5. eLife 2016; 5. [PMID: 27474797 PMCID: PMC5011436 DOI: 10.7554/elife.14216] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 07/28/2016] [Indexed: 12/18/2022] Open
Abstract
RNA-binding proteins contribute to the formation of ribonucleoprotein (RNP) granules by phase transition, but regulatory mechanisms are not fully understood. Conserved fission yeast NDR (Nuclear Dbf2-Related) kinase Orb6 governs cell morphogenesis in part by spatially controlling Cdc42 GTPase. Here we describe a novel, independent function for Orb6 kinase in negatively regulating the recruitment of RNA-binding protein Sts5 into RNPs to promote polarized cell growth. We find that Orb6 kinase inhibits Sts5 recruitment into granules, its association with processing (P) bodies, and degradation of Sts5-bound mRNAs by promoting Sts5 interaction with 14-3-3 protein Rad24. Many Sts5-bound mRNAs encode essential factors for polarized cell growth, and Orb6 kinase spatially and temporally controls the extent of Sts5 granule formation. Disruption of this control system affects cell morphology and alters the pattern of polarized cell growth, revealing a role for Orb6 kinase in the spatial control of translational repression that enables normal cell morphogenesis.
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Affiliation(s)
- Illyce Nuñez
- Molecular and Cellular Pharmacology, University of Miami School of Medicine, Miami, United States
| | - Marbelys Rodriguez Pino
- Molecular and Cellular Pharmacology, University of Miami School of Medicine, Miami, United States
| | - David J Wiley
- Molecular and Cellular Pharmacology, University of Miami School of Medicine, Miami, United States
| | - Maitreyi E Das
- Department of Biochemistry and Cellular and Molecular Biology, The University of Tennessee, Knoxville, United States
| | - Chuan Chen
- Molecular and Cellular Pharmacology, University of Miami School of Medicine, Miami, United States
| | - Tetsuya Goshima
- National Research Institute of Brewing, Higashi-Hiroshima, Japan
| | - Kazunori Kume
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Japan
| | - Dai Hirata
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Japan
| | - Takashi Toda
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Japan.,The Francis Crick Institute, Lincoln's Inn Fields Laboratory, London, United Kingdom
| | - Fulvia Verde
- Molecular and Cellular Pharmacology, University of Miami School of Medicine, Miami, United States.,Marine Biological Laboratory, Woods Hole, United States
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212
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Wucherer-Plietker M, Merkul E, Müller TJ, Esdar C, Knöchel T, Heinrich T, Buchstaller HP, Greiner H, Dorsch D, Finsinger D, Calderini M, Bruge D, Grädler U. Discovery of novel 7-azaindoles as PDK1 inhibitors. Bioorg Med Chem Lett 2016; 26:3073-3080. [DOI: 10.1016/j.bmcl.2016.05.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 05/02/2016] [Accepted: 05/03/2016] [Indexed: 11/30/2022]
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213
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McManus S, Bisson M, Chamberland R, Roy M, Nazari S, Roux S. Autophagy and 3-Phosphoinositide-Dependent Kinase 1 (PDK1)-Related Kinome in Pagetic Osteoclasts. J Bone Miner Res 2016; 31:1334-43. [PMID: 26848537 DOI: 10.1002/jbmr.2806] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 01/24/2016] [Accepted: 02/03/2016] [Indexed: 01/30/2023]
Abstract
In Paget's disease of bone (PDB), a major contributory factor are osteoclasts (OCs) that are larger, more numerous, resistant to apoptosis, and hyperactive. The aim of this human in vitro study was to identify kinase cascades involved in the OC phenotype and to determine their impact on downstream processes. Basal phosphorylation levels of Akt and ERK were found to be elevated in PDB OCs. Given our previous findings that 3-phosphoinositide-dependent protein kinase 1 (PDK1) associates with the crucial adaptor p62 in OCs, we hypothesized that PDK1 may play an important role in OC-related kinome regulation. The increased phosphorylation of Akt and its substrate GSK3β observed in PDB OCs was reduced significantly upon PDK1 inhibition, as well as that of 4EBP1 and Raptor. This suggests a PDK1/Akt-dependent activation of mammalian target of rapamycin complex 1 (mTORC1) in PDB OCs. The resistance to apoptosis and the bone resorption were also overcome upon PDK1 inhibition. Studying autophagy by LC3B expression, we found a less inducible autophagy compared with control cells, which was reversed by PDK1 inhibition. In addition, PBD OCs exhibited higher LC3B-II/LC3B-I ratios and numbers of p62 and LC3B puncta per OC area, which did not further increase in the presence of lysosomal protease inhibitors, suggesting an accumulation of non-degradative autophagosomes. Together these results indicate a strong potential regulatory role for PDK1 in OC stimulatory pathways (Akt, ERK) and autophagy induction (via mTORC1), which may contribute to the OC phenotype in PDB. We also identified defects in late autophagosome maturation in these cells, the mechanism of which remains to be determined. © 2016 American Society for Bone and Mineral Research.
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Affiliation(s)
- Stephen McManus
- Division of Rheumatology, Faculty of Medicine, University of Sherbrooke, Sherbrooke, Canada
| | - Martine Bisson
- Division of Rheumatology, Faculty of Medicine, University of Sherbrooke, Sherbrooke, Canada
| | - Richard Chamberland
- Division of Rheumatology, Faculty of Medicine, University of Sherbrooke, Sherbrooke, Canada
| | - Michèle Roy
- Division of Rheumatology, Faculty of Medicine, University of Sherbrooke, Sherbrooke, Canada
| | - Shekeba Nazari
- Division of Rheumatology, Faculty of Medicine, University of Sherbrooke, Sherbrooke, Canada
| | - Sophie Roux
- Division of Rheumatology, Faculty of Medicine, University of Sherbrooke, Sherbrooke, Canada
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214
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Chen K, Lin G, Haelterman NA, Ho TSY, Li T, Li Z, Duraine L, Graham BH, Jaiswal M, Yamamoto S, Rasband MN, Bellen HJ. Loss of Frataxin induces iron toxicity, sphingolipid synthesis, and Pdk1/Mef2 activation, leading to neurodegeneration. eLife 2016; 5:e16043. [PMID: 27343351 PMCID: PMC4956409 DOI: 10.7554/elife.16043] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 06/24/2016] [Indexed: 12/22/2022] Open
Abstract
Mutations in Frataxin (FXN) cause Friedreich's ataxia (FRDA), a recessive neurodegenerative disorder. Previous studies have proposed that loss of FXN causes mitochondrial dysfunction, which triggers elevated reactive oxygen species (ROS) and leads to the demise of neurons. Here we describe a ROS independent mechanism that contributes to neurodegeneration in fly FXN mutants. We show that loss of frataxin homolog (fh) in Drosophila leads to iron toxicity, which in turn induces sphingolipid synthesis and ectopically activates 3-phosphoinositide dependent protein kinase-1 (Pdk1) and myocyte enhancer factor-2 (Mef2). Dampening iron toxicity, inhibiting sphingolipid synthesis by Myriocin, or reducing Pdk1 or Mef2 levels, all effectively suppress neurodegeneration in fh mutants. Moreover, increasing dihydrosphingosine activates Mef2 activity through PDK1 in mammalian neuronal cell line suggesting that the mechanisms are evolutionarily conserved. Our results indicate that an iron/sphingolipid/Pdk1/Mef2 pathway may play a role in FRDA.
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Affiliation(s)
- Kuchuan Chen
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Guang Lin
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Nele A Haelterman
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Tammy Szu-Yu Ho
- Department of Neuroscience, Baylor College of Medicine, Houston, United States
| | - Tongchao Li
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Zhihong Li
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Lita Duraine
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States
| | - Brett H Graham
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Manish Jaiswal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States
| | - Shinya Yamamoto
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, United States
| | - Matthew N Rasband
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
- Department of Neuroscience, Baylor College of Medicine, Houston, United States
| | - Hugo J Bellen
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
- Department of Neuroscience, Baylor College of Medicine, Houston, United States
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, United States
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Zhu H, Wang X, Pan H, Dai Y, Li N, Wang L, Yang H, Gong F. The Mechanism by Which Safflower Yellow Decreases Body Fat Mass and Improves Insulin Sensitivity in HFD-Induced Obese Mice. Front Pharmacol 2016; 7:127. [PMID: 27242533 PMCID: PMC4876777 DOI: 10.3389/fphar.2016.00127] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 05/05/2016] [Indexed: 12/22/2022] Open
Abstract
Objectives: Safflower yellow (SY) is the main effective ingredient of Carthamus tinctorius L. It has been reported that SY plays an important role in anti-inflammation, anti-platelet aggregation, and inhibiting thrombus formation. In present study, we try to investigate the effects of SY on body weight, body fat mass, insulin sensitivity in high fat diet (HFD)-induced obese mice. Methods: HFD-induced obese male ICR mice were intraperitoneally injected with SY (120 mg kg−1) daily. Eight weeks later, intraperitoneal insulin tolerance test (IPITT), and intraperitoneal glucose tolerance test (IPGTT) were performed, and body weight, body fat mass, serum insulin levels were measured. The expression of glucose and lipid metabolic related genes in white adipose tissue (WAT) were determined by RT-qPCR and western blot technologies. Results: The administration obese mice with SY significantly reduced the body fat mass of HFD-induced obese mice (P < 0.05). IPITT test showed that the insulin sensitivity of SY treated obese mice were evidently improved. The mRNA levels of insulin signaling pathway related genes including insulin receptor substrate 1(IRS1), PKB protein kinase (AKT), glycogen synthase kinase 3β (GSK3β) and forkhead box protein O1(FOXO1) in mesenteric WAT of SY treated mice were significantly increased to 1.9- , 2.8- , 3.3- , and 5.9-folds of that in HFD-induced control obese mice, respectively (P < 0.05). The protein levels of AKT and GSK3β were also significantly increased to 3.0 and 5.2-folds of that in HFD-induced control obese mice, respectively (P < 0.05). Meanwhile, both the mRNA and protein levels of peroxisome proliferator-activated receptorgamma coactivator 1α (PGC1α) in inguinal subcutaneous WAT of SY group were notably increased to 2.5 and 3.0-folds of that in HFD-induced control obese mice (P < 0.05). Conclusions: SY significantly reduce the body fat mass, fasting blood glucose and increase insulin sensitivity of HFD-induced obese mice. The possible mechanism is to promote the browning of subcutaneous WAT and activate the IRS1/AKT/GSK3β pathway in visceral WAT. Our study provides an important experimental evidence for developing SY as a potential anti-obesity and anti-diabetic drug.
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Affiliation(s)
- Huijuan Zhu
- Key Laboratory of Endocrinology of National Health and Family Planning Commission, Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Science Beijing, China
| | - Xiangqing Wang
- Key Laboratory of Endocrinology of National Health and Family Planning Commission, Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Science Beijing, China
| | - Hui Pan
- Key Laboratory of Endocrinology of National Health and Family Planning Commission, Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Science Beijing, China
| | - Yufei Dai
- Key Laboratory of Endocrinology of National Health and Family Planning Commission, Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Science Beijing, China
| | - Naishi Li
- Key Laboratory of Endocrinology of National Health and Family Planning Commission, Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Science Beijing, China
| | - Linjie Wang
- Key Laboratory of Endocrinology of National Health and Family Planning Commission, Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Science Beijing, China
| | - Hongbo Yang
- Key Laboratory of Endocrinology of National Health and Family Planning Commission, Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Science Beijing, China
| | - Fengying Gong
- Key Laboratory of Endocrinology of National Health and Family Planning Commission, Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Science Beijing, China
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Pauta M, Rotllan N, Fernández-Hernando A, Langhi C, Ribera J, Lu M, Boix L, Bruix J, Jimenez W, Suárez Y, Ford DA, Baldán A, Birnbaum MJ, Morales-Ruiz M, Fernández-Hernando C. Akt-mediated foxo1 inhibition is required for liver regeneration. Hepatology 2016; 63:1660-74. [PMID: 26473496 PMCID: PMC5177729 DOI: 10.1002/hep.28286] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 09/18/2015] [Accepted: 10/13/2015] [Indexed: 12/24/2022]
Abstract
UNLABELLED Understanding the hepatic regenerative process has clinical interest as the effectiveness of many treatments for chronic liver diseases is conditioned by efficient liver regeneration. Experimental evidence points to the need for a temporal coordination between cytokines, growth factors, and metabolic signaling pathways to enable successful liver regeneration. One intracellular mediator that acts as a signal integration node for these processes is the serine-threonine kinase Akt/protein kinase B (Akt). To investigate the contribution of Akt during hepatic regeneration, we performed partial hepatectomy in mice lacking Akt1, Akt2, or both isoforms. We found that absence of Akt1 or Akt2 does not influence liver regeneration after partial hepatectomy. However, hepatic-specific Akt1 and Akt2 null mice show impaired liver regeneration and increased mortality. The major abnormal cellular events observed in total Akt-deficient livers were a marked reduction in cell proliferation, cell hypertrophy, glycogenesis, and lipid droplet formation. Most importantly, liver-specific deletion of FoxO1, a transcription factor regulated by Akt, rescued the hepatic regenerative capability in Akt1-deficient and Akt2-deficient mice and normalized the cellular events associated with liver regeneration. CONCLUSION The Akt-FoxO1 signaling pathway plays an essential role during liver regeneration.
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Affiliation(s)
- Montse Pauta
- Department of Biochemistry and Molecular Genetics, Hospital Clinic of Barcelona, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Centro de Investigaciones Biomédicas en Red en Enfermedades Hepáticas y Digestivas (CIBERehd), Barcelona, Spain,Departments of Medicine and Cell Biology, Leon H. Charney Division of Cardiology, New York University School of Medicine, New York, New York, USA
| | - Noemi Rotllan
- Departments of Medicine and Cell Biology, Leon H. Charney Division of Cardiology, New York University School of Medicine, New York, New York, USA,Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, Connecticut, USA,Integrative Cell Signaling and Neurobiology of Metabolism Program, Section of Comparative Medicine and Department of Pathology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Ana Fernández-Hernando
- Departments of Medicine and Cell Biology, Leon H. Charney Division of Cardiology, New York University School of Medicine, New York, New York, USA
| | - Cedric Langhi
- Edward A. Doisy Department of Biochemistry & Molecular Biology, and Center for Cardiovascular Research, Saint Louis University, Saint Louis, Missuri, USA
| | - Jordi Ribera
- Department of Biochemistry and Molecular Genetics, Hospital Clinic of Barcelona, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Centro de Investigaciones Biomédicas en Red en Enfermedades Hepáticas y Digestivas (CIBERehd), Barcelona, Spain
| | - Mingjian Lu
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Loreto Boix
- Barcelona Clinic Liver Cancer (BCLC) Group, Liver Unit, Hospital Clínic of Barcelona, University of Barcelona, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), CIBERehd, Barcelona, Spain
| | - Jordi Bruix
- Barcelona Clinic Liver Cancer (BCLC) Group, Liver Unit, Hospital Clínic of Barcelona, University of Barcelona, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), CIBERehd, Barcelona, Spain
| | - Wladimiro Jimenez
- Department of Biochemistry and Molecular Genetics, Hospital Clinic of Barcelona, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Centro de Investigaciones Biomédicas en Red en Enfermedades Hepáticas y Digestivas (CIBERehd), Barcelona, Spain,Department of Physiological Sciences I, University of Barcelona, Barcelona, Spain
| | - Yajaira Suárez
- Departments of Medicine and Cell Biology, Leon H. Charney Division of Cardiology, New York University School of Medicine, New York, New York, USA,Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, Connecticut, USA,Integrative Cell Signaling and Neurobiology of Metabolism Program, Section of Comparative Medicine and Department of Pathology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - David A. Ford
- Edward A. Doisy Department of Biochemistry & Molecular Biology, and Center for Cardiovascular Research, Saint Louis University, Saint Louis, Missuri, USA
| | - Angel Baldán
- Edward A. Doisy Department of Biochemistry & Molecular Biology, and Center for Cardiovascular Research, Saint Louis University, Saint Louis, Missuri, USA
| | - Morris J. Birnbaum
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Manuel Morales-Ruiz
- Department of Biochemistry and Molecular Genetics, Hospital Clinic of Barcelona, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Centro de Investigaciones Biomédicas en Red en Enfermedades Hepáticas y Digestivas (CIBERehd), Barcelona, Spain,Department of Physiological Sciences I, University of Barcelona, Barcelona, Spain,Corresponding authors: Manuel Morales-Ruiz, Ph.D., Department of Biochemistry and Molecular Genetics, Hospital Clinic of Barcelona, 170 Villarroel St, Barcelona, 08036, Spain, Tel: 011-34-932275466; Fax: 011-34-932275697; ., Carlos Fernandez-Hernando, Ph.D., Vascular Biology and Therapeutics Program, Yale University School of Medicine, 10 Amistad Street, New Haven, CT06520, Tel: 2037374615; Fax: 2037372290;
| | - Carlos Fernández-Hernando
- Departments of Medicine and Cell Biology, Leon H. Charney Division of Cardiology, New York University School of Medicine, New York, New York, USA,Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, Connecticut, USA,Integrative Cell Signaling and Neurobiology of Metabolism Program, Section of Comparative Medicine and Department of Pathology, Yale University School of Medicine, New Haven, Connecticut, USA,Corresponding authors: Manuel Morales-Ruiz, Ph.D., Department of Biochemistry and Molecular Genetics, Hospital Clinic of Barcelona, 170 Villarroel St, Barcelona, 08036, Spain, Tel: 011-34-932275466; Fax: 011-34-932275697; ., Carlos Fernandez-Hernando, Ph.D., Vascular Biology and Therapeutics Program, Yale University School of Medicine, 10 Amistad Street, New Haven, CT06520, Tel: 2037374615; Fax: 2037372290;
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Park H, Lee S, Shrestha P, Kim J, Park JA, Ko Y, Ban YH, Park DY, Ha SJ, Koh GY, Hong VS, Mochizuki N, Kim YM, Lee W, Kwon YG. AMIGO2, a novel membrane anchor of PDK1, controls cell survival and angiogenesis via Akt activation. J Cell Biol 2016; 211:619-37. [PMID: 26553931 PMCID: PMC4639856 DOI: 10.1083/jcb.201503113] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
AMIGO2 is a novel scaffold protein that regulates PDK1 membrane localization and Akt activation in endothelial cells, and inhibition of the interaction between PDK1–AMIGO2 results in impaired neovascularization, pathological angiogenesis, and tumor angiogenesis. The phosphoinositide 3-kinase–Akt signaling pathway is essential to many biological processes, including cell proliferation, survival, metabolism, and angiogenesis, under pathophysiological conditions. Although 3-phosphoinositide–dependent kinase 1 (PDK1) is a primary activator of Akt at the plasma membrane, the optimal activation mechanism remains unclear. We report that adhesion molecule with IgG-like domain 2 (AMIGO2) is a novel scaffold protein that regulates PDK1 membrane localization and Akt activation. Loss of AMIGO2 in endothelial cells (ECs) led to apoptosis and inhibition of angiogenesis with Akt inactivation. Amino acid residues 465–474 in AMIGO2 directly bind to the PDK1 pleckstrin homology domain. A synthetic peptide containing the AMIGO2 465–474 residues abrogated the AMIGO2–PDK1 interaction and Akt activation. Moreover, it effectively suppressed pathological angiogenesis in murine tumor and oxygen-induced retinopathy models. These results demonstrate that AMIGO2 is an important regulator of the PDK1–Akt pathway in ECs and suggest that interference of the PDK1–AMIGO2 interaction might be a novel pharmaceutical target for designing an Akt pathway inhibitor.
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Affiliation(s)
- Hyojin Park
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
| | - Sungwoon Lee
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
| | - Pravesh Shrestha
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
| | - Jihye Kim
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
| | - Jeong Ae Park
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
| | - Yeongrim Ko
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
| | - Young Ho Ban
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
| | - Dae-Young Park
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Sang-Jun Ha
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
| | - Gou Young Koh
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Victor Sukbong Hong
- College of Natural Sciences, Keimyung University, Daegu 42601, Republic of Korea
| | - Naoki Mochizuki
- Department of Cell Biology, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka 565-8565, Japan
| | - Young-Myeong Kim
- Vascular System Research Center, Kangwon National University, Chuncheon, Kangwon 24341, Republic of Korea
| | - Weontae Lee
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
| | - Young-Guen Kwon
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
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218
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14-3-3 Proteins regulate Akt Thr308 phosphorylation in intestinal epithelial cells. Cell Death Differ 2016; 23:1060-72. [PMID: 26846144 DOI: 10.1038/cdd.2015.163] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 11/14/2015] [Accepted: 11/24/2015] [Indexed: 12/11/2022] Open
Abstract
Akt activation has been associated with proliferation, differentiation, survival and death of epithelial cells. Phosphorylation of Thr308 of Akt by phosphoinositide-dependent kinase 1 (PDK1) is critical for optimal stimulation of its kinase activity. However, the mechanism(s) regulating this process remain elusive. Here, we report that 14-3-3 proteins control Akt Thr308 phosphorylation during intestinal inflammation. Mechanistically, we found that IFNγ and TNFα treatment induce degradation of the PDK1 inhibitor, 14-3-3η, in intestinal epithelial cells. This mechanism requires association of 14-3-3ζ with raptor in a process that triggers autophagy and leads to 14-3-3η degradation. Notably, inhibition of 14-3-3 function by the chemical inhibitor BV02 induces uncontrolled Akt activation, nuclear Akt accumulation and ultimately intestinal epithelial cell death. Our results suggest that 14-3-3 proteins control Akt activation and regulate its biological functions, thereby providing a new mechanistic link between cell survival and apoptosis of intestinal epithelial cells during inflammation.
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219
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Teixeira V, Costa V. Unraveling the role of the Target of Rapamycin signaling in sphingolipid metabolism. Prog Lipid Res 2015; 61:109-33. [PMID: 26703187 DOI: 10.1016/j.plipres.2015.11.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 11/04/2015] [Accepted: 11/09/2015] [Indexed: 02/06/2023]
Abstract
Sphingolipids are important bioactive molecules that regulate basic aspects of cellular metabolism and physiology, including cell growth, adhesion, migration, senescence, apoptosis, endocytosis, and autophagy in yeast and higher eukaryotes. Since they have the ability to modulate the activation of several proteins and signaling pathways, variations in the relative levels of different sphingolipid species result in important changes in overall cellular functions and fate. Sphingolipid metabolism and their route of synthesis are highly conserved from yeast to mammalian cells. Studies using the budding yeast Saccharomyces cerevisiae have served in many ways to foster our understanding of sphingolipid dynamics and their role in the regulation of cellular processes. In the past decade, studies in S. cerevisiae have unraveled a functional association between the Target of Rapamycin (TOR) pathway and sphingolipids, showing that both TOR Complex 1 (TORC1) and TOR Complex 2 (TORC2) branches control temporal and spatial aspects of sphingolipid metabolism in response to physiological and environmental cues. In this review, we report recent findings in this emerging and exciting link between the TOR pathway and sphingolipids and implications in human health and disease.
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Affiliation(s)
- Vitor Teixeira
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal; IBMC, Instituto de Biologia Molecular e Celular, Porto, Portugal; ICBAS, Instituto de Ciências Biomédicas Abel Salazar, Departamento de Biologia Molecular, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Vítor Costa
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal; IBMC, Instituto de Biologia Molecular e Celular, Porto, Portugal; ICBAS, Instituto de Ciências Biomédicas Abel Salazar, Departamento de Biologia Molecular, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
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220
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Abstract
The heart is adapted to utilize all classes of substrates to meet the high-energy demand, and it tightly regulates its substrate utilization in response to environmental changes. Although fatty acids are known as the predominant fuel for the adult heart at resting stage, the heart switches its substrate preference toward glucose during stress conditions such as ischemia and pathological hypertrophy. Notably, increasing evidence suggests that the loss of metabolic flexibility associated with increased reliance on glucose utilization contribute to the development of cardiac dysfunction. The changes in glucose metabolism in hypertrophied hearts include altered glucose transport and increased glycolysis. Despite the role of glucose as an energy source, changes in other nonenergy producing pathways related to glucose metabolism, such as hexosamine biosynthetic pathway and pentose phosphate pathway, are also observed in the diseased hearts. This article summarizes the current knowledge regarding the regulation of glucose transporter expression and translocation in the heart during physiological and pathological conditions. It also discusses the signaling mechanisms governing glucose uptake in cardiomyocytes, as well as the changes of cardiac glucose metabolism under disease conditions.
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Affiliation(s)
- Dan Shao
- Mitochondria and Metabolism Center, University of Washington, Seattle, Washington, USA
| | - Rong Tian
- Mitochondria and Metabolism Center, University of Washington, Seattle, Washington, USA
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221
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Carnagarin R, Dharmarajan AM, Dass CR. Molecular aspects of glucose homeostasis in skeletal muscle--A focus on the molecular mechanisms of insulin resistance. Mol Cell Endocrinol 2015; 417:52-62. [PMID: 26362689 DOI: 10.1016/j.mce.2015.09.004] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Accepted: 09/02/2015] [Indexed: 01/14/2023]
Abstract
Among all the varied actions of insulin, regulation of glucose homeostasis is the most critical and intensively studied. With the availability of glucose from nutrient metabolism, insulin action in muscle results in increased glucose disposal via uptake from the circulation and storage of excess, thereby maintaining euglycemia. This major action of insulin is executed by redistribution of the glucose transporter protein, GLUT4 from intracellular storage sites to the plasma membrane and storage of glucose in the form of glycogen which also involves modulation of actin dynamics that govern trafficking of all the signal proteins of insulin signal transduction. The cellular mechanisms responsible for these trafficking events and the defects associated with insulin resistance are largely enigmatic, and this review provides a consolidated overview of the various molecular mechanisms involved in insulin-dependent glucose homeostasis in skeletal muscle, as insulin resistance at this major peripheral site impacts whole body glucose homeostasis.
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Affiliation(s)
- Revathy Carnagarin
- Curtin Biosciences Research Precinct, Bentley 6102, Australia; School of Pharmacy, Curtin University, Bentley 6102, Australia
| | - Arun M Dharmarajan
- Curtin Biosciences Research Precinct, Bentley 6102, Australia; School of Biomedical Science, Curtin University, Bentley 6102, Australia
| | - Crispin R Dass
- Curtin Biosciences Research Precinct, Bentley 6102, Australia; School of Pharmacy, Curtin University, Bentley 6102, Australia.
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222
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PDK1: A signaling hub for cell migration and tumor invasion. Biochim Biophys Acta Rev Cancer 2015; 1856:178-88. [DOI: 10.1016/j.bbcan.2015.07.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 07/28/2015] [Indexed: 01/22/2023]
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223
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Dong X, Tang S, Zhang W, Gao W, Chen Y. GPR39 activates proliferation and differentiation of porcine intramuscular preadipocytes through targeting the PI3K/AKT cell signaling pathway. J Recept Signal Transduct Res 2015; 36:130-8. [PMID: 26524639 DOI: 10.3109/10799893.2015.1056308] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND The orphan G protein-coupled receptor (GPR) 39 was originally identified as the receptor of obestatin. In this study, the effects and mechanisms of GPR39 on cell proliferation and differentiation were investigated in cultured porcine intramuscular preadipocytes. METHODS Morphology of preadipocytes and accumulated lipid droplets within cells were identified by an inverted microscope. After transfected with constructed pCMV-GPR39 plasmid, cell proliferation was measured by using methyl thiazolyl tetrazolium method, mRNA expression of GPR39, CCAAT/enhancer binding protein-α (C/EBPα), peroxisome proliferator-activated receptor-γ (PPARγ), Caspase-9 and adipocyte determination and differentiation factor-1 (ADD1) was determined by RNA preparation and reverse transcription polymerase chain reaction, protein expression of phosphoinositide-3 kinase (PI3K), 3-phosphoinositide-dependent protein kinase 1, phosphorylated glycogen synthase kinase 3 (pGSK3), total Akt and phosphorylated Akt (pAkt) was analyzed by Western blot. RESULTS It found that GPR39 mRNA and protein were expressed in porcine intramuscular preadipocytes and its expression was significantly up-regulated after treatment with Zn(2+) whose function is found to be mediated by GPR39. Furthermore, over-expression of GPR39 further promoted the optical density value of cells, enhanced mRNA expression of PPARγ, C/EBPα and ADD1, and inhibited mRNA expression of Caspase-9. Protein expression of pGSK3 and pAkt was also increased by GPR39 stimulation. In addition, GPR39-induced proliferation and differentiation of porcine intramuscular preadipocytes was partially blocked by the Akt inhibitor (PDTC) and the PI3K inhibitor (LY294002). CONCLUSION It indicated that GPR39 was a transducer of Zn(2+), and enhanced proliferation and differentiation of porcine intramuscular preadipocytes through activation of the PI3K/Akt signaling pathway.
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Affiliation(s)
- Xiaoying Dong
- a College of Yingdong Agricultural Science and Engineering, Shaoguan University , Shaoguan , P.R. China
| | - Shengqiu Tang
- a College of Yingdong Agricultural Science and Engineering, Shaoguan University , Shaoguan , P.R. China
| | - Wei Zhang
- b Hubei Key Laboratory of Animal Embryo and Molecular Breeding, Hubei Academy of Agricultural Science , Wuhan , P.R. China
| | - Weihua Gao
- c College of Animal Science, Yangtze Univeisity , Jingzhou , P.R. China , and
| | - Yanfei Chen
- d College of Yingdong Life Science, Shaoguan University , Shaoguan , P.R. China
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224
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Noh J, Wende AR, Olsen CD, Kim B, Bevins J, Zhu Y, Zhang QJ, Riehle C, Abel ED. Phosphoinositide dependent protein kinase 1 is required for exercise-induced cardiac hypertrophy but not the associated mitochondrial adaptations. J Mol Cell Cardiol 2015; 89:297-305. [PMID: 26476238 DOI: 10.1016/j.yjmcc.2015.10.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 09/28/2015] [Accepted: 10/12/2015] [Indexed: 01/17/2023]
Abstract
Phosphoinositide-dependent protein kinase-1 (PDPK1) is an important mediator of phosphatidylinositol 3-kinase (PI3K) signaling. We previously reported that PI3K but not Akt signaling mediates the increase in mitochondrial oxidative capacity following physiological cardiac hypertrophy. To determine if PDPK1 regulates these metabolic adaptations we examined mice with cardiomyocyte-specific heterozygous knockout of PDPK1 (cPDPK1(+/-)) after 5 wk. exercise swim training. Akt phosphorylation at Thr308 increased by 43% in wildtype (WT) mice but not in cPDPK1(+/-) mice following exercise training. Ventricular contractile function was not different between WT and cPDPK1(+/-) mice at baseline. In addition, exercise did not influence ventricular function in WT or cPDPK1(+/-) mice. Heart weight normalized to tibia length ratios increased by 13.8% in WT mice (6.2±0.2 vs. 7.1±0.2, P=0.001), but not in cPDPK1(+/-) (6.2±0.3 vs. 6.5±0.2, P=0.20) mice after swim training. Diastolic LV dimension increased in WT mice (3.7±0.1 vs. 4.0±0.1 mm, P=0.01) but not in cPDPK1(+/-) (3.8±0.1 vs. 3.7±0.1 mm, P=0.56) following swim training. Maximal mitochondrial oxygen consumption (VADP, nmol/min/mg) using palmitoyl carnitine as a substrate was significantly increased in mice of all genotypes following swim training (WT: 13.6±0.6 vs.16.1±0.9, P=0.04; cPDPK1(+/-): 12.4±0.6 vs.15.9±1.2, P=0.04). These findings suggest that PDPK1 is required for exercise-induced cardiac hypertrophy but does not contribute to exercise-induced increases in mitochondrial function.
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Affiliation(s)
- Junghyun Noh
- Program in Molecular Medicine and Division of Endocrinology, Metabolism and Diabetes, University of Utah School of Medicine, Salt Lake City, UT 84112, USA; Division of Endocrinology and Metabolism, College of Medicine, Inje University, Goyang, South Korea
| | - Adam R Wende
- Program in Molecular Medicine and Division of Endocrinology, Metabolism and Diabetes, University of Utah School of Medicine, Salt Lake City, UT 84112, USA; Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Curtis D Olsen
- Program in Molecular Medicine and Division of Endocrinology, Metabolism and Diabetes, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Bumjun Kim
- Program in Molecular Medicine and Division of Endocrinology, Metabolism and Diabetes, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Jack Bevins
- Program in Molecular Medicine and Division of Endocrinology, Metabolism and Diabetes, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Yi Zhu
- Program in Molecular Medicine and Division of Endocrinology, Metabolism and Diabetes, University of Utah School of Medicine, Salt Lake City, UT 84112, USA; Touchstone Diabetes Center, University of Texas Southwestern, Dallas, TX 75390, USA
| | - Quan-Jiang Zhang
- Program in Molecular Medicine and Division of Endocrinology, Metabolism and Diabetes, University of Utah School of Medicine, Salt Lake City, UT 84112, USA; Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Christian Riehle
- Program in Molecular Medicine and Division of Endocrinology, Metabolism and Diabetes, University of Utah School of Medicine, Salt Lake City, UT 84112, USA; Hannover Medical School, Department of Cardiology and Angiology, Carl-Neuberg-Str., 130625 Hannover, Germany
| | - E Dale Abel
- Program in Molecular Medicine and Division of Endocrinology, Metabolism and Diabetes, University of Utah School of Medicine, Salt Lake City, UT 84112, USA; Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.
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225
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Affiliation(s)
- Shawn M. Ferguson
- Department of Cell Biology and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University, New Haven, CT 06510, USA
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226
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Wheeler DB, Zoncu R, Root DE, Sabatini DM, Sawyers CL. Identification of an oncogenic RAB protein. Science 2015; 350:211-7. [PMID: 26338797 PMCID: PMC4600465 DOI: 10.1126/science.aaa4903] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Accepted: 08/24/2015] [Indexed: 12/16/2022]
Abstract
In a short hairpin RNA screen for genes that affect AKT phosphorylation, we identified the RAB35 small guanosine triphosphatase (GTPase)-a protein previously implicated in endomembrane trafficking-as a regulator of the phosphatidylinositol 3'-OH kinase (PI3K) pathway. Depletion of RAB35 suppresses AKT phosphorylation in response to growth factors, whereas expression of a dominant active GTPase-deficient mutant of RAB35 constitutively activates the PI3K/AKT pathway. RAB35 functions downstream of growth factor receptors and upstream of PDK1 and mTORC2 and copurifies with PI3K in immunoprecipitation assays. Two somatic RAB35 mutations found in human tumors generate alleles that constitutively activate PI3K/AKT signaling, suppress apoptosis, and transform cells in a PI3K-dependent manner. Furthermore, oncogenic RAB35 is sufficient to drive platelet-derived growth factor receptor α to LAMP2-positive endomembranes in the absence of ligand, suggesting that there may be latent oncogenic potential in dysregulated endomembrane trafficking.
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Affiliation(s)
- Douglas B Wheeler
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center (MSKCC), New York, NY 10065, USA. Weill Cornell/Rockefeller University/Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY 10021, USA. Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Roberto Zoncu
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - David E Root
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - David M Sabatini
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA. Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA. Department of Biology, Massachusetts Institute of Technology (MIT), Cambridge, MA 02142, USA. David H. Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA 02142, USA. Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA.
| | - Charles L Sawyers
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center (MSKCC), New York, NY 10065, USA. Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA.
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227
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Conservation of gene and tissue networks regulating insulin signalling in flies and vertebrates. Biochem Soc Trans 2015; 43:1057-62. [DOI: 10.1042/bst20150078] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Fruit flies have emerged as a powerful tool to investigate metabolism. Not only are gene structures and gene networks that control metabolism conserved through evolution, but the interactions among organs to store and process metabolites have strong similarities between flies and humans. Accordingly, the Drosophila system has the potential to address human disorders associated with metabolic dysfunction including obesity, type 2 diabetes and lipotoxicity.
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228
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Qi L, Toyoda H, Xu DQ, Zhou Y, Sakurai N, Amano K, Kihira K, Hori H, Azuma E, Komada Y. PDK1-mTOR signaling pathway inhibitors reduce cell proliferation in MK2206 resistant neuroblastoma cells. Cancer Cell Int 2015; 15:91. [PMID: 26421002 PMCID: PMC4587771 DOI: 10.1186/s12935-015-0239-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 09/04/2015] [Indexed: 02/08/2023] Open
Abstract
Purpose AKT plays a pivotal role in the signal transduction of cancer cells. MK2206, an AKT inhibitor, has been shown to be an effective anti-cancer drug to a variety of cancer cell lines. However, some cancer cells acquire resistance to MK2206 and new strategies to suppress these cell lines remain to be developed. Experimental design Acquired MK-2206-resistant neuroblastoma (NB) cell sublines were induced by stepwise escalation of MK-2206 exposure (4–12 weeks). MTT assay was used to validate cell proliferation. Flow cytometry was performed for cell cycle analysis. Western blot assay was used for cell signaling study. Results MK2206 (5–10 µmol) significantly suppressed cell growth of MK2206 non-resistant NB cells (LAN-1, KP-N-SIFA, NB-19 and SK-N-DZ), but is less efficient in inhibiting that of resistant sublines, even after 2-week MK2206-free incubation. MK2206 acted in mTOR-S6K dependent and independent methods. MK-2206 resistant sublines (LAN-1-MK, KP-N-SIFA-MK, and SK-N-DZ-MK) showed lower IC50 of GSK2334470 (PDK1 inhibitor). The cell growth of all sublines was prohibited by AZD8805 (mTOR inhibitor), with IC50 of AZD8805 3–10 times lower than MK2206 non-resistant cells. The signaling profiles of these resistant sublines were characterized by elevated PDK1-mTOR-S6K activity, accompanying by low phosphorylation of AKT compared with non-resistant counterparts. GSK2334470 and AZD8055 effectively inhibited phosphorylation of PDK1 and mTOR, respectively, and induced higher G0–G1 ratio in LAN-1-MK than that in LAN-1 as well. PDK1 and mTOR inhibitors effected on phosphorylation of GSK3β in some of resistant sublines. Conclusion NB cells can acquire MK2206 resistance after exposure for 4–12 weeks. Resistant cells feature reliance on PDK1-mTOR-S6K pathway and are more sensitive to PDK1 and mTOR inhibitors than the non-resistant counterparts. Thus, suppression of PDK1-mTOR-S6K signaling pathway is an effective way to overcome the MK2206 resistance, and this may be a promising strategy for targeted therapy.
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Affiliation(s)
- Lei Qi
- Department of Pediatrics and Developmental Science, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507 Japan ; Department of Pediatrics, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, 1665 Kong Jiang Road, Shanghai, 200092 China
| | - Hidemi Toyoda
- Department of Pediatrics and Developmental Science, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507 Japan
| | - Dong-Qing Xu
- Department of Pediatrics and Developmental Science, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507 Japan ; Department of Pediatrics, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, 1665 Kong Jiang Road, Shanghai, 200092 China
| | - Ye Zhou
- Department of Child Health Nursing, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507 Japan
| | - Naoto Sakurai
- Department of Pediatrics and Developmental Science, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507 Japan
| | - Keishirou Amano
- Department of Pediatrics and Developmental Science, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507 Japan
| | - Kentaro Kihira
- Department of Pediatrics and Developmental Science, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507 Japan
| | - Hiroki Hori
- Department of Pediatrics and Developmental Science, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507 Japan
| | - Eiichi Azuma
- Department of Pediatrics and Developmental Science, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507 Japan
| | - Yoshihiro Komada
- Department of Pediatrics and Developmental Science, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507 Japan
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229
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Xi JC, Zang HY, Guo LX, Xue HB, Liu XD, Bai YB, Ma YZ. The PI3K/AKT cell signaling pathway is involved in regulation of osteoporosis. J Recept Signal Transduct Res 2015; 35:640-5. [PMID: 26390889 DOI: 10.3109/10799893.2015.1041647] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Osteoporosis is a systemic skeletal disease with the high incidence, serious complications, financial burden, and heavily decrease in living quality. METHODS Proliferation of osteoblast was tested by 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) method, alkaline phosphatase (ALP) activity of osteoblasts was tested by ALP REAGENT, Calcium level was determined by a colorimetric assay, mRNA expression of phosphoinositide-3 kinase (PI3K), 3-phosphoinositide-dependent protein kinase 1 (PDK1), Akt, Caspase-3, Caspase-7, Caspase-9, osteocalcin (OCN), Osterix and Runx2 of osteoblasts was tested by RNA preparation and quantitative reverse transcription polymerase chain reaction (RT-PCR), and protein expression of phospho-PI3K, phospho-PDK1 and phospho-Akt was measured by Western Blot analysis. RESULTS In osteoporosis model rats, it found that mRNA expression of PI3K, PDK1 and Akt showed no changes while protein expression of phospho-PI3K, phospho-PDK1 and phospho-Akt in bone tissue was decreased dramatically. To further characterize the molecular mechanisms that regulate osteoporosis, we examined the contribution of the PI3K/Akt cell signaling pathway in cultured osteoblasts. It suggested that, the blockade of PI3K activation by LY294002, a specific inhibitor of the PI3K/Akt signaling pathway in osteoblasts, heavily inhibited cell proliferation, ALP activity, calcium accumulation, and mRNA expression of OCN, Osterix and Runx2. However, mRNA expression of Caspase-3 and Caspase-9 was promoted accordingly. CONCLUSION The in vivo and in vitro studies indicated that the PI3K/Akt cell signaling pathway is involved in the inhibition of osteoporosis through promoting osteoblast proliferation, differentiation and bone formation.
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Affiliation(s)
- Jian-Cheng Xi
- a Orthopaedic Department , 309 Hospital of People's Liberation Army , Beijing , China and
| | - Hai-Yu Zang
- b Outpatient Department , Command College of Land Force of People's Liberation Army , Shijiazhuang City , China
| | - Li-Xin Guo
- a Orthopaedic Department , 309 Hospital of People's Liberation Army , Beijing , China and
| | - Hai-Bin Xue
- a Orthopaedic Department , 309 Hospital of People's Liberation Army , Beijing , China and
| | - Xiang-Dong Liu
- a Orthopaedic Department , 309 Hospital of People's Liberation Army , Beijing , China and
| | - Yi-Bing Bai
- a Orthopaedic Department , 309 Hospital of People's Liberation Army , Beijing , China and
| | - Yuan-Zheng Ma
- a Orthopaedic Department , 309 Hospital of People's Liberation Army , Beijing , China and
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230
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Zhou X, Cordon-Barris L, Zurashvili T, Bayascas JR. Fine-tuning the intensity of the PKB/Akt signal enables diverse physiological responses. Cell Cycle 2015; 13:3164-8. [PMID: 25485494 DOI: 10.4161/15384101.2014.962954] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The PI3K/PDK1/PKB signaling pathway plays essential roles in regulating neuronal survival, differentiation and plasticity in response to neurotrophic factors, neurotransmitters and ion channels. Both PDK1 and PKB can interact at the plasma membrane with a phosphoinositide synthesized by PI3K, the second messenger PtdIns(3,4,5)P3, enabling PDK1 to phosphorylate and activate PKB. In the PDK1 K465E knock-in mice expressing a mutant form of PDK1 incapable of phosphoinositide binding, activation of PKB was markedly affected, but not totally abolished. It has been recently proposed that in the absence of PtdIns(3,4,5)P3 binding, PDK1 can still moderately activate PKB due to a docking site-mediated interaction of these 2 kinases. A recent report has uncovered that in the PDK1 K465E mice neurons, a PKB signal threshold was sufficient to support neuronal survival responses, whereas neuritogenesis, neuronal polarization and axon outgrowth were severely impaired. We propose here that the low-efficiency mechanism of PKB activation observed in the PDK1 K465E mice might represent the ancestral mechanism responsible for the essential functions of this pathway, while the phosphoinositide-dependent activation should be considered an evolutionary innovation that enabled the acquisition of novel functions.
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Affiliation(s)
- Xiangyu Zhou
- a Institut de Neurociències & Departament de Bioquímica i Biologia Molecular ; Universitat Autònoma de Barcelona ; Barcelona , Spain
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231
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Kriplani N, Hermida MA, Brown ER, Leslie NR. Class I PI 3-kinases: Function and evolution. Adv Biol Regul 2015; 59:53-64. [PMID: 26159297 DOI: 10.1016/j.jbior.2015.05.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 05/25/2015] [Indexed: 06/04/2023]
Abstract
In many human cell types, the class I phosphoinositide 3-kinases play key roles in the control of diverse cellular processes including growth, proliferation, survival and polarity. This is achieved through their activation by many cell surface receptors, leading to the synthesis of the phosphoinositide lipid signal, PIP3, which in turn influences the function of numerous direct PIP3-binding proteins. Here we review PI3K pathway biology and analyse the evolutionary distribution of its components and their functions. The broad phylogenetic distribution of class I PI3Ks in metazoa, amoebozoa and choannoflagellates, implies that these enzymes evolved in single celled organisms and were later co-opted into metazoan intercellular communication. A similar distribution is evident for the AKT and Cytohesin groups of downstream PIP3-binding proteins, with other effectors and pathway components appearing to evolve later. The genomic and functional phylogeny of regulatory systems such as the PI3K pathway provides a framework to improve our understanding of the mechanisms by which key cellular processes are controlled in humans.
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Affiliation(s)
- Nisha Kriplani
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot Watt University, Edinburgh, EH14 4AS, UK
| | - Miguel A Hermida
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot Watt University, Edinburgh, EH14 4AS, UK
| | - Euan R Brown
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot Watt University, Edinburgh, EH14 4AS, UK
| | - Nicholas R Leslie
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot Watt University, Edinburgh, EH14 4AS, UK.
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232
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Dibble CC, Cantley LC. Regulation of mTORC1 by PI3K signaling. Trends Cell Biol 2015; 25:545-55. [PMID: 26159692 DOI: 10.1016/j.tcb.2015.06.002] [Citation(s) in RCA: 573] [Impact Index Per Article: 63.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 06/08/2015] [Accepted: 06/08/2015] [Indexed: 11/29/2022]
Abstract
The class I phosphoinositide 3-kinase (PI3K)-mechanistic target of rapamycin (mTOR) complex 1 (mTORC1) signaling network directs cellular metabolism and growth. Activation of mTORC1 [composed of mTOR, regulatory-associated protein of mTOR (Raptor), mammalian lethal with SEC13 protein 8(mLST8), 40-kDa proline-rich Akt substrate (PRAS40), and DEP domain-containing mTOR-interacting protein (DEPTOR)] depends on the Ras-related GTPases (Rags) and Ras homolog enriched in brain (Rheb) GTPase and requires signals from amino acids, glucose, oxygen, energy (ATP), and growth factors (including cytokines and hormones such as insulin). Here we discuss the signal transduction mechanisms through which growth factor-responsive PI3K signaling activates mTORC1. We focus on how PI3K-dependent activation of Akt and spatial regulation of the tuberous sclerosis complex (TSC) complex (TSC complex) [composed of TSC1, TSC2, and Tre2-Bub2-Cdc16-1 domain family member 7 (TBC1D7)] switches on Rheb at the lysosome, where mTORC1 is activated. Integration of PI3K- and amino acid-dependent signals upstream of mTORC1 at the lysosome is detailed in a working model. A coherent understanding of the PI3K-mTORC1 network is imperative as its dysregulation has been implicated in diverse pathologies including cancer, diabetes, autism, and aging.
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Affiliation(s)
- Christian C Dibble
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Lewis C Cantley
- Meyer Cancer Center, Department of Medicine, Weill Cornell Medical College, New York, NY 10065, USA.
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233
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Lang UE, Ackermann TF, Wolfer D, Schubert F, Sohr R, Hörtnagl H, Lang F, Gallinat J. Phosphoinositide-Dependent Protein Kinase 1 (PDK1). ZEITSCHRIFT FUR PSYCHOLOGIE-JOURNAL OF PSYCHOLOGY 2015. [DOI: 10.1027/2151-2604/a000217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Abstract. Phosphatidylinositol-3-kinase (PI3K) signaling influences susceptibility to virus infections, anoxia, obstetric complications, and cancer; which are changed in patients with schizophrenia and their first degree relatives. Therefore PI3K signaling might have impact on the pathophysiology of schizophrenia. PI3K signaling crucially involves phosphoinositide-dependent protein kinase (PDK1). Increased anxiety behavior is observed in PDK1 hypomorphic mice. Here we show enhanced prevalence of schizophrenia in carriers of the PDK1 CC genotype in human beings. Moreover, decreased parietal P300 amplitude, which is a well-studied schizophrenic endophenotype, was observed in PDK1 CC carriers. Glutamate and glutamine concentrations are increased in the frontal lobe of PDK1 dysmorphic mice and human CC individuals. Our results demonstrate that the PDK1 CC genotype is associated with increased risk to develop schizophrenia, a typical endophenotype profile observed in the disease and modified neurotransmitter concentrations in brain regions associated with the disease.
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Affiliation(s)
- Undine E. Lang
- Department of Psychiatry and Psychotherapy, University of Basel, Switzerland
| | | | - David Wolfer
- Institute of Anatomy, University of Zurich and Department of Biology, ETH Zurich, Switzerland
| | | | - Reinhard Sohr
- Department of Pharmacology, Charité University Medicine Berlin, Germany
| | - Heide Hörtnagl
- Department of Pharmacology, University of Innsbruck, Austria
| | - Florian Lang
- Department of Physiology I, University of Tuebingen, Germany
| | - Juergen Gallinat
- Department of Psychiatry and Psychotherapy, University Hospital Hamburg, Germany
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234
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Yu M, Owens DM, Ghosh S, Farber DL. Conditional PDK1 Ablation Promotes Epidermal and T-Cell-Mediated Dysfunctions Leading to Inflammatory Skin Disease. J Invest Dermatol 2015; 135:2688-2696. [PMID: 26099023 PMCID: PMC4640961 DOI: 10.1038/jid.2015.232] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 05/19/2015] [Accepted: 06/01/2015] [Indexed: 01/13/2023]
Abstract
Phosphoinositide-dependent kinase-1 (PDK1) is a key signaling molecule downstream of the phosphatidylinositol 3-kinase pathway and is a master regulator of multiple kinases in cells of epithelial and hematopoietic lineages. The physiological role of PDK1 in regulating skin and immune homeostasis is not known. Here we developed a mouse model in which PDK1 is conditionally ablated in activated CD4 T cells, regulatory T cells, and mature keratinocytes through OX40-Cre recombinase expression. The resultant mice (PDK1-CKO) spontaneously developed severe dermatitis, skin fibrosis, and systemic T helper type 2 immunity, succumbing by 11 weeks of age. Through a series of T-cell transfers, bone marrow reconstitutions, and crossing to lymphocyte-deficient backgrounds, we demonstrate that ablation of PDK1 in keratinocytes is the major driver of disease pathogenesis. PDK1-deficient keratinocytes exhibit intrinsic defects in the expression of key structural proteins including cytokeratin-10 and loricrin, resulting in increased keratinocyte turnover, which in turn triggers inflammation, T-cell recruitment, and immune-mediated destruction. Our results reveal PDK1 as a central regulator of keratinocyte homeostasis that prevents skin immune infiltration and inflammation.
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Affiliation(s)
- Minjun Yu
- Columbia Center for Translational Immunology, Columbia University Medical Center, New York, New York, USA; Department of Medicine, Columbia University, New York, New York, USA
| | - David M Owens
- Department of Dermatology, Columbia University, New York, New York, USA; Department of Pathology and Cell Biology, Columbia University, New York, New York, USA
| | - Sankar Ghosh
- Department of Microbiology and Immunology, Columbia University, New York, New York, USA
| | - Donna L Farber
- Columbia Center for Translational Immunology, Columbia University Medical Center, New York, New York, USA; Department of Microbiology and Immunology, Columbia University, New York, New York, USA; Department of Surgery, Columbia University, New York, New York, USA.
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235
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Tashima T. The structural use of carbostyril in physiologically active substances. Bioorg Med Chem Lett 2015; 25:3415-9. [PMID: 26112444 DOI: 10.1016/j.bmcl.2015.06.027] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 06/04/2015] [Accepted: 06/06/2015] [Indexed: 11/16/2022]
Abstract
Carbostyril (2-quinolinone, 2-quinolone) is an important structural component frequently used in natural products and in physiologically active substances including drugs. It is a 2-ring condensed heterocyclic compound containing several positions that can be replaced by arbitrary substituent groups and is used as a chemical building block, scaffold, fragment, and pharmacophore in drug design or discovery. Since the number of compounds that can be designed using carbostyril is exceedingly large, the steric structures of carbostyril derivatives can be adjusted to the unique, spatially oriented shape of, for example, the active sites of pharmaceutical target molecules. Moreover, the internal amide of the carbostyril unit exhibits distinctive features because of the fixed cis form of the lactam amide group. Because carbostyril has been used as a component in drugs and other bioactive compounds over time, carbostyril derivatives may improve absorption, distribution, metabolism, excretion, and toxicity (ADMET). Therefore, carbostyril derivatives have enormous potential. In this review, the potential and advantages of the use of carbostyril and its related molecular skeletons, such as 3,4-dihydrocarbostyril, are discussed by focusing on the physiologically active substances in which they are incorporated.
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Affiliation(s)
- Toshihiko Tashima
- Nippon Pharmaceutical Chemicals Co., Ltd, 2-8-18 Chodo, Higashi-Osaka, Osaka 577-0056, Japan.
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236
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Xu Z, Liao B, Zhang R, Yao J, Shi R, Wang L. Expression of 3-phosphoinositide-dependent protein kinase 1 in colorectal cancer as a potential therapeutic target. Med Oncol 2015; 32:198. [PMID: 26055151 DOI: 10.1007/s12032-015-0645-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 05/21/2015] [Indexed: 01/05/2023]
Abstract
3-Phosphoinositide-dependent protein kinase 1 (PDK1) is centrally involved in cancer progression, including proliferation, apoptosis and invasion. However, its expression pattern and possible cellular functions in human colorectal cancer remain unclear. In the present study, we show that PDK1 expression is up-regulated at both mRNA and protein levels in colorectal cancer clinical specimens and cell lines. Transient knockdown of PDK1 suppresses cellular growth, induces cellular apoptosis and causes abnormal cell cycle distribution. Meanwhile, decreased PDK1 level is closely associated with reduced Akt/cyclin D1 activity. Activating AKT activity and reintroducing cyclin D1 expression significantly compromised the oncogenic activity induced by PDK1. Together, our findings elucidate a key role for PDK1 in colorectal cellular functions trigged by the Akt/cyclin D1 pathway, thus providing a novel insight of PDK1 in colorectal carcinogenesis.
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Affiliation(s)
- Zhenglei Xu
- Department of Gastroenterology, Shenzhen People's Hospital, Second Clinical Medical College of Jinan University, 1017#, North Dongmen Road, Shenzhen, 518000, Guangdong Province, People's Republic of China
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237
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Lim KM, An S, Lee OK, Lee MJ, Lee JP, Lee KS, Lee GT, Lee KK, Bae S. Analysis of changes in microRNA expression profiles in response to the troxerutin-mediated antioxidant effect in human dermal papilla cells. Mol Med Rep 2015; 12:2650-60. [PMID: 25955790 PMCID: PMC4464413 DOI: 10.3892/mmr.2015.3717] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Accepted: 03/26/2015] [Indexed: 01/08/2023] Open
Abstract
Dermal papilla (DP) cells function as important regulators of the hair growth cycle. The loss of these cells is a primary cause of diseases characterized by hair loss, including alopecia, and evidence has revealed significantly increased levels of reactive oxygen species (ROS) in hair tissue and DP cells in the balding population. In the present study, troxerutin, a flavonoid derivative of rutin, was demonstrated to have a protective effect against H2O2-mediated cellular damage in human DP (HDP) cells. Biochemical assays revealed that pretreatment with troxerutin exerted a protective effect against H2O2-induced loss of cell viability and H2O2 induced cell death. Further experiments confirmed that troxerutin inhibited the H2O2-induced production of ROS and upregulation of senescence-associated β-galactosidase activity. Using microRNA (miRNA) microarrays, the present study identified 24 miRNAs, which were differentially expressed in the troxerutin pretreated, H2O2-treated HDP cells. Subsequent prediction using bioinformatics analysis revealed that the altered miRNAs were functionally involved in several cell signaling pathways, including the mitogen-activated protein kinase and WNT pathways. Overall, these results indicated that ROS-mediated cellular damage was inhibited by troxerutin and suggested that the use of troxerutin may be an effective approach in the treatment of alopecia.
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Affiliation(s)
- Kyung Mi Lim
- Molecular‑Targeted Drug Research Center and Korea Institute for Skin and Clinical Sciences, Konkuk University, Seoul 143‑701, Republic of Korea
| | - Sungkwan An
- Molecular‑Targeted Drug Research Center and Korea Institute for Skin and Clinical Sciences, Konkuk University, Seoul 143‑701, Republic of Korea
| | - Ok-Kyu Lee
- Molecular‑Targeted Drug Research Center and Korea Institute for Skin and Clinical Sciences, Konkuk University, Seoul 143‑701, Republic of Korea
| | - Myung Joo Lee
- Molecular‑Targeted Drug Research Center and Korea Institute for Skin and Clinical Sciences, Konkuk University, Seoul 143‑701, Republic of Korea
| | - Jeong Pyo Lee
- Coreana Cosmetics Co., Ltd., Cheonan, Chungcheong 330‑882, Republic of Korea
| | - Kwang Sik Lee
- Coreana Cosmetics Co., Ltd., Cheonan, Chungcheong 330‑882, Republic of Korea
| | - Ghang Tai Lee
- Coreana Cosmetics Co., Ltd., Cheonan, Chungcheong 330‑882, Republic of Korea
| | - Kun Kook Lee
- Coreana Cosmetics Co., Ltd., Cheonan, Chungcheong 330‑882, Republic of Korea
| | - Seunghee Bae
- Molecular‑Targeted Drug Research Center and Korea Institute for Skin and Clinical Sciences, Konkuk University, Seoul 143‑701, Republic of Korea
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No YR, He P, Yoo BK, Yun CC. Regulation of NHE3 by lysophosphatidic acid is mediated by phosphorylation of NHE3 by RSK2. Am J Physiol Cell Physiol 2015; 309:C14-21. [PMID: 25855080 DOI: 10.1152/ajpcell.00067.2015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 04/07/2015] [Indexed: 01/29/2023]
Abstract
Na(+)/H(+) exchange by Na(+)/H(+) exchanger 3 (NHE3) is a major route of sodium absorption in the intestine and kidney. We have shown previously that lysophosphatidic acid (LPA), a small phospholipid produced ubiquitously by all types of cells, stimulates NHE3 via LPA5 receptor. Stimulation of NHE3 activity by LPA involves LPA5 transactivating EGF receptor (EGFR) in the apical membrane. EGFR activates proline-rich tyrosine kinase 2 (Pyk2) and ERK, both of which are necessary for NHE3 regulation. However, Pyk2 and ERK are regulated by EGFR via independent pathways and appear to converge on an unidentified intermediate that ultimately targets NHE3. The p90 ribosomal S6 kinase (RSK) family of Ser/Thr protein kinases is a known effector of EGFR and ERK. Hence, we hypothesized that RSK may be the convergent effector of Pyk2 and ERK although it is not known whether Pyk2 regulates RSK. In this study, we show that Pyk2 is necessary for the maintenance of phosphoinositide-dependent kinase 1 (PDK1) autophosphorylation, and knockdown of Pyk2 or PDK1 mitigated LPA-induced phosphorylation of RSK and stimulation of NHE3 activity. Additionally, we show that RSK2, but not RSK1, is responsible for NHE3 regulation. RSK2 interacts with NHE3 at the apical membrane domain, where it phosphorylates NHE3. Alteration of S663 of NHE3 ablated LPA-induced phosphorylation of NHE3 and stimulation of the transport activity. Our study identifies RSK2 as a new kinase that regulates NHE3 activity by direct phosphorylation.
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Affiliation(s)
- Yi Ran No
- Division of Digestive Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Peijian He
- Division of Digestive Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Byong Kwon Yoo
- Division of Digestive Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - C Chris Yun
- Division of Digestive Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia; Winship Cancer Institute, Emory University, Atlanta, Georgia
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239
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Abstract
In MCF-7 breast cancer cells epidermal growth factor (EGF) induces cell proliferation, whereas heregulin (HRG)/neuregulin (NRG) induces irreversible phenotypic changes accompanied by lipid accumulation. Although these changes in breast cancer cells resemble processes that take place in the tissue, there is no understanding of signalling mechanisms regulating it. To identify molecular mechanisms mediating this cell-fate decision process, we applied different perturbations to pathways activated by these growth factors. The results demonstrate that phosphoinositide 3 (PI3) kinase (PI3K) and mammalian target of rapamycin (mTOR) complex (mTORC)1 activation is necessary for lipid accumulation that can also be induced by insulin, whereas stimulation of the extracellular-signal-regulated kinase (ERK) pathway is surprisingly dispensable. Interestingly, insulin exposure, as short as 4 h, was sufficient for triggering the lipid accumulation, whereas much longer treatment with HRG was required for achieving similar cellular response. Further, activation patterns of ATP citrate lyase (ACLY), an enzyme playing a central role in linking glycolytic and lipogenic pathways, suggest that lipids accumulated within cells are produced de novo rather than absorbed from the environment. In the present study, we demonstrate that PI3K pathway regulates phenotypic changes in breast cancer cells, whereas signal intensity and duration is crucial for cell fate decisions and commitment. Our findings reveal that MCF-7 cell fate decisions are controlled by a network of positive and negative regulators of both signalling and metabolic pathways. Excessive production and accumulation of lipids is often observed in breast cancer tissue. In the current study, we investigate signalling mechanisms regulating this process using a model cell line.
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240
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Deletion of PDK1 causes cardiac sodium current reduction in mice. PLoS One 2015; 10:e0122436. [PMID: 25781322 PMCID: PMC4363661 DOI: 10.1371/journal.pone.0122436] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 02/14/2015] [Indexed: 01/01/2023] Open
Abstract
Background The AGC protein kinase family regulates multiple cellular functions. 3-phosphoinositide-dependent protein kinase-1 (PDK1) is involved in the pathogenesis of arrhythmia, and its downstream factor, Forkhead box O1 (Foxo1), negatively regulates the expression of the cardiac sodium channel, Nav1.5. Mice are known to die suddenly after PDK1 deletion within 11 weeks, but the underlying electrophysiological bases are unclear. Thus, the aim of this study was to investigate the potential mechanisms between PDK1 signaling pathway and cardiac sodium current. Methods and Results Using patch clamp and western blotting techniques, we investigated the role of the PDK1-Foxo1 pathway in PDK1 knockout mice and cultured cardiomyocytes. We found that PDK1 knockout mice undergo slower heart rate, prolonged QRS and QTc intervals and abnormal conduction within the first few weeks of birth. Furthermore, the peak sodium current is decreased by 33% in cells lacking PDK1. The phosphorylation of Akt (308T) and Foxo1 (24T) and the expression of Nav1.5 in the myocardium of PDK1-knockout mice are decreased, while the nuclear localization of Foxo1 is increased. The role of the PDK1-Foxo1 pathway in regulating Nav1.5 levels and sodium current density was verified using selective PDK1, Akt and Foxo1 inhibitors and isolated neonatal rat cardiomyocytes. Conclusion These results indicate that PDK1 participates in the dysregulation of electrophysiological basis by regulating the PDK1-Foxo1 pathway, which in turn regulates the expression of Nav1.5 and cardiac sodium channel function.
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241
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Scortegagna M, Lau E, Zhang T, Feng Y, Sereduk C, Yin H, De SK, Meeth K, Platt JT, Langdon CG, Halaban R, Pellecchia M, Davies MA, Brown K, Stern DF, Bosenberg M, Ronai ZA. PDK1 and SGK3 Contribute to the Growth of BRAF-Mutant Melanomas and Are Potential Therapeutic Targets. Cancer Res 2015; 75:1399-412. [PMID: 25712345 DOI: 10.1158/0008-5472.can-14-2785] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 01/20/2015] [Indexed: 01/24/2023]
Abstract
Melanoma development involves members of the AGC kinase family, including AKT, PKC, and, most recently, PDK1, as elucidated recently in studies of Braf::Pten mutant melanomas. Here, we report that PDK1 contributes functionally to skin pigmentation and to the development of melanomas harboring a wild-type PTEN genotype, which occurs in about 70% of human melanomas. The PDK1 substrate SGK3 was determined to be an important mediator of PDK1 activities in melanoma cells. Genetic or pharmacologic inhibition of PDK1 and SGK3 attenuated melanoma growth by inducing G1 phase cell-cycle arrest. In a synthetic lethal screen, pan-PI3K inhibition synergized with PDK1 inhibition to suppress melanoma growth, suggesting that focused blockade of PDK1/PI3K signaling might offer a new therapeutic modality for wild-type PTEN tumors. We also noted that responsiveness to PDK1 inhibition associated with decreased expression of pigmentation genes and increased expression of cytokines and inflammatory genes, suggesting a method to stratify patients with melanoma for PDK1-based therapies. Overall, our work highlights the potential significance of PDK1 as a therapeutic target to improve melanoma treatment.
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Affiliation(s)
- Marzia Scortegagna
- Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California
| | - Eric Lau
- Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California
| | - Tongwu Zhang
- Division of Cancer Epidemiology and Genetics, Laboratory of Translational Genomics, NCI, Bethesda, Maryland
| | - Yongmei Feng
- Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California
| | - Chris Sereduk
- Cancer and Cell Biology Division, The Translational Genomics Research Institute (TGen), Phoenix, Arizona
| | - Hongwei Yin
- Cancer and Cell Biology Division, The Translational Genomics Research Institute (TGen), Phoenix, Arizona
| | - Surya K De
- Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California
| | - Katrina Meeth
- Department of Dermatology, Yale University, School of Medicine, New Haven, Connecticut. Department of Pathology, Yale University, School of Medicine, New Haven, Connecticut
| | - James T Platt
- Department of Dermatology, Yale University, School of Medicine, New Haven, Connecticut. Department of Pathology, Yale University, School of Medicine, New Haven, Connecticut
| | - Casey G Langdon
- Department of Dermatology, Yale University, School of Medicine, New Haven, Connecticut. Department of Pathology, Yale University, School of Medicine, New Haven, Connecticut
| | - Ruth Halaban
- Department of Dermatology, Yale University, School of Medicine, New Haven, Connecticut
| | - Maurizio Pellecchia
- Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California
| | - Michael A Davies
- Melanoma Medical Oncology, MD Anderson Cancer Center, Houston, Texas
| | - Kevin Brown
- Division of Cancer Epidemiology and Genetics, Laboratory of Translational Genomics, NCI, Bethesda, Maryland
| | - David F Stern
- Department of Pathology, Yale University, School of Medicine, New Haven, Connecticut
| | - Marcus Bosenberg
- Department of Dermatology, Yale University, School of Medicine, New Haven, Connecticut. Department of Pathology, Yale University, School of Medicine, New Haven, Connecticut
| | - Ze'ev A Ronai
- Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California.
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242
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The SARS-coronavirus membrane protein induces apoptosis via interfering with PDK1-PKB/Akt signalling. Biochem J 2015; 464:439-47. [PMID: 25271362 DOI: 10.1042/bj20131461] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A number of viral gene products are capable of inducing apoptosis by interfering with various cellular signalling cascades. We previously reported the pro-apoptotic property of the SARS-CoV (severe acute respiratory syndrome coronavirus) M (membrane)-protein and a down-regulation of the phosphorylation level of the cell-survival protein PKB (protein kinase B)/Akt in cells expressing M-protein. We also showed that overexpression of PDK1 (3-phosphoinositide-dependent protein kinase 1), the immediate upstream kinase of PKB/Akt, suppressed M-induced apoptosis. This illustrates that M-protein perturbs the PDK1 and PKB/Akt cell survival signalling pathway. In the present study, we demonstrated that the C-terminus of M-protein interacts with the PH (pleckstrin homology) domain of PDK1. This interaction disrupted the association between PDK1 and PKB/Akt, and led to down-regulation of PKB/Akt activity. This subsequently reduced the level of the phosphorylated forkhead transcription factor FKHRL1 and ASK (apoptosis signal-regulating kinase), and led to the activation of caspases 8 and 9. Altogether, our data demonstrate that the SARS-CoV M-protein induces apoptosis through disrupting the interaction of PDK1 with PKB/Akt, and this causes the activation of apoptosis. Our work highlights that the SARS-CoV M protein is highly pro-apoptotic and is capable of simultaneously inducing apoptosis via initiating caspases 8 and 9. Preventing the interaction between M-protein and PDK1 is a plausible therapeutic approach to target the pro-apoptotic property of SARS-CoV.
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243
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Hossen MJ, Kim SC, Yang S, Kim HG, Jeong D, Yi YS, Sung NY, Lee JO, Kim JH, Cho JY. PDK1 disruptors and modulators: a patent review. Expert Opin Ther Pat 2015; 25:513-37. [PMID: 25684022 DOI: 10.1517/13543776.2015.1014801] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
INTRODUCTION 3-Phosphoinositide-dependent kinase 1 (PDK1) is a master regulator of the AGC protein kinase family and is a critical activator of multiple pro-survival and oncogenic protein kinases, for which it has garnered considerable interest as an oncology drug target. AREAS COVERED This manuscript reviews small molecule patent literature disclosures between October 2011 and September 2014 for both PDK1 activators and inhibitors and restates the selective patents published before September 2011. PDK1 modulators are organized according to pharmaceutical company and chemical structural class. EXPERT OPINION Many academic institutions and pharmaceutical companies continue to research into the development of small molecules that can function as PDK1 inhibitors or modulators. To date, >50 patent publications on PDK1 disruptors and modulators have been published since the protein was first discovered in 1998. Most of these molecules act as ATP mimetics, forming similar hydrogen bonding patterns to PDK1 as ATP and functioning as hydrophobic pharmacophores. To achieve selectivity in PDK1 inhibition, the discovery of binding pockets structurally distinctive from the ATP site is a challenging but promising strategy.
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Affiliation(s)
- Muhammad Jahangir Hossen
- Sungkyunkwan University, Department of Genetic Engineering , 300 Chuncheon-Dong, Suwon 440-746 , Korea +82 31 290 7868 ; +82 31 290 7870 ;
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244
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He J, Qi D, Wang DX, Deng W, Ye Y, Feng LH, Zhu T, Zhao Y, Zhang CR. Insulin upregulates the expression of epithelial sodium channel in vitro and in a mouse model of acute lung injury: Role of mTORC2/SGK1 pathway. Exp Cell Res 2015; 331:164-175. [DOI: 10.1016/j.yexcr.2014.09.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 09/03/2014] [Accepted: 09/18/2014] [Indexed: 01/04/2023]
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245
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Verma R, Marchese A. The endosomal sorting complex required for transport pathway mediates chemokine receptor CXCR4-promoted lysosomal degradation of the mammalian target of rapamycin antagonist DEPTOR. J Biol Chem 2015; 290:6810-24. [PMID: 25605718 DOI: 10.1074/jbc.m114.606699] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
G protein-coupled receptor (GPCR) signaling mediates many cellular functions, including cell survival, proliferation, and cell motility. Many of these processes are mediated by GPCR-promoted activation of Akt signaling by mammalian target of rapamycin complex 2 (mTORC2) and the phosphatidylinositol 3-kinase (PI3K)/phosphoinositide-dependent kinase 1 (PDK1) pathway. However, the molecular mechanisms by which GPCRs govern Akt activation by these kinases remain poorly understood. Here, we show that the endosomal sorting complex required for transport (ESCRT) pathway mediates Akt signaling promoted by the chemokine receptor CXCR4. Pharmacological inhibition of heterotrimeric G protein Gαi or PI3K signaling and siRNA targeting ESCRTs blocks CXCR4-promoted degradation of DEPTOR, an endogenous antagonist of mTORC2 activity. Depletion of ESCRTs by siRNA leads to increased levels of DEPTOR and attenuated CXCR4-promoted Akt activation and signaling, consistent with decreased mTORC2 activity. In addition, ESCRTs likely have a broad role in Akt signaling because ESCRT depletion also attenuates receptor tyrosine kinase-promoted Akt activation and signaling. Our data reveal a novel role for the ESCRT pathway in promoting intracellular signaling, which may begin to identify the signal transduction pathways that are important in the physiological roles of ESCRTs and Akt.
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Affiliation(s)
- Rita Verma
- From the Biochemistry and Molecular Biology Program, and
| | - Adriano Marchese
- From the Biochemistry and Molecular Biology Program, and Department of Molecular Pharmacology and Therapeutics, Health Sciences Division, Loyola University Chicago, Maywood, Illinois 60153
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246
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Abstract
Three theories of regeneration dominate neuroscience today, all purporting to explain why the adult central nervous system (CNS) cannot regenerate. One theory proposes that Nogo, a molecule expressed by myelin, prevents axonal growth. The second theory emphasizes the role of glial scars. The third theory proposes that chondroitin sulfate proteoglycans (CSPGs) prevent axon growth. Blockade of Nogo, CSPG, and their receptors indeed can stop axon growth in vitro and improve functional recovery in animal spinal cord injury (SCI) models. These therapies also increase sprouting of surviving axons and plasticity. However, many investigators have reported regenerating spinal tracts without eliminating Nogo, glial scar, or CSPG. For example, many motor and sensory axons grow spontaneously in contused spinal cords, crossing gliotic tissue and white matter surrounding the injury site. Sensory axons grow long distances in injured dorsal columns after peripheral nerve lesions. Cell transplants and treatments that increase cAMP and neurotrophins stimulate motor and sensory axons to cross glial scars and to grow long distances in white matter. Genetic studies deleting all members of the Nogo family and even the Nogo receptor do not always improve regeneration in mice. A recent study reported that suppressing the phosphatase and tensin homolog (PTEN) gene promotes prolific corticospinal tract regeneration. These findings cannot be explained by the current theories proposing that Nogo and glial scars prevent regeneration. Spinal axons clearly can and will grow through glial scars and Nogo-expressing tissue under some circumstances. The observation that deleting PTEN allows corticospinal tract regeneration indicates that the PTEN/AKT/mTOR pathway regulates axonal growth. Finally, many other factors stimulate spinal axonal growth, including conditioning lesions, cAMP, glycogen synthetase kinase inhibition, and neurotrophins. To explain these disparate regenerative phenomena, I propose that the spinal cord has evolved regenerative mechanisms that are normally suppressed by multiple extrinsic and intrinsic factors but can be activated by injury, mediated by the PTEN/AKT/mTOR, cAMP, and GSK3b pathways, to stimulate neural growth and proliferation.
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Affiliation(s)
- Wise Young
- W. M. Keck Center for Collaborative Neuroscience, Rutgers, State University of New Jersey, Piscataway, NJ, USA
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247
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O’Neill C, Li Y, Jin X. Survival Signalling in the Preimplantation Embryo. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 843:129-49. [DOI: 10.1007/978-1-4939-2480-6_5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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248
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Singh S, Srivastava P. Molecular Docking Studies of Myricetin and Its Analogues against Human PDK-1 Kinase as Candidate Drugs for Cancer. ACTA ACUST UNITED AC 2015. [DOI: 10.4236/cmb.2015.52004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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249
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di Blasio L, Gagliardi PA, Puliafito A, Sessa R, Seano G, Bussolino F, Primo L. PDK1 regulates focal adhesion disassembly through modulation of αvβ3 integrin endocytosis. J Cell Sci 2015; 128:863-77. [DOI: 10.1242/jcs.149294] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Non-amoeboid cell migration is characterised by dynamic competition among multiple protrusions to establish new adhesion sites at the cell's leading edge. However, the mechanisms that regulate the decision to disassemble or to grow nascent adhesions are not fully understood.
Here we show that in endothelial cells (EC) 3-phosphoinositide-dependent protein (PDK1) promotes focal adhesions (FA) turnover by controlling endocytosis of integrin αvβ3 in a PI3K-dependent manner. We demonstrate that PDK1 binds and phosphorylates integrin αvβ3. Down-regulation of PDK1 increases FA size and slows down their disassembly. This process requires both PDK1 kinase activity and PI3K activation but does not involve Akt. Moreover, PDK1 silencing stabilizes FA in membrane protrusions decreasing EC migration on vitronectin.
These results indicate that modulation of integrin endocytosis by PDK1 hampers EC adhesion and migration on extracellular matrix, thus unveiling a novel role for this kinase.
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250
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Wu CYC, Carpenter ES, Takeuchi KK, Halbrook CJ, Peverley LV, Bien H, Hall JC, DelGiorno KE, Pal D, Song Y, Shi C, Lin RZ, Crawford HC. PI3K regulation of RAC1 is required for KRAS-induced pancreatic tumorigenesis in mice. Gastroenterology 2014; 147:1405-16.e7. [PMID: 25311989 PMCID: PMC4252806 DOI: 10.1053/j.gastro.2014.08.032] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 08/20/2014] [Accepted: 08/21/2014] [Indexed: 12/28/2022]
Abstract
BACKGROUND & AIMS New drug targets are urgently needed for the treatment of patients with pancreatic ductal adenocarcinoma (PDA). Nearly all PDAs contain oncogenic mutations in the KRAS gene. Pharmacological inhibition of KRAS has been unsuccessful, leading to a focus on downstream effectors that are more easily targeted with small molecule inhibitors. We investigated the contributions of phosphoinositide 3-kinase (PI3K) to KRAS-initiated tumorigenesis. METHODS Tumorigenesis was measured in the Kras(G12D/+);Ptf1a(Cre/+) mouse model of PDA; these mice were crossed with mice with pancreas-specific disruption of genes encoding PI3K p110α (Pik3ca), p110β (Pik3cb), or RAC1 (Rac1). Pancreatitis was induced with 5 daily intraperitoneal injections of cerulein. Pancreata and primary acinar cells were isolated; acinar cells were incubated with an inhibitor of p110α (PIK75) followed by a broad-spectrum PI3K inhibitor (GDC0941). PDA cell lines (NB490 and MiaPaCa2) were incubated with PIK75 followed by GDC0941. Tissues and cells were analyzed by histology, immunohistochemistry, quantitative reverse-transcription polymerase chain reaction, and immunofluorescence analyses for factors involved in the PI3K signaling pathway. We also examined human pancreas tissue microarrays for levels of p110α and other PI3K pathway components. RESULTS Pancreas-specific disruption of Pik3ca or Rac1, but not Pik3cb, prevented the development of pancreatic tumors in Kras(G12D/+);Ptf1a(Cre/+) mice. Loss of transformation was independent of AKT regulation. Preneoplastic ductal metaplasia developed in mice lacking pancreatic p110α but regressed. Levels of activated and total RAC1 were higher in pancreatic tissues from Kras(G12D/+);Ptf1a(Cre/+) mice compared with controls. Loss of p110α reduced RAC1 activity and expression in these tissues. p110α was required for the up-regulation and activity of RAC guanine exchange factors during tumorigenesis. Levels of p110α and RAC1 were increased in human pancreatic intraepithelial neoplasias and PDAs compared with healthy pancreata. CONCLUSIONS KRAS signaling, via p110α to activate RAC1, is required for transformation in Kras(G12D/+);Ptf1a(Cre/+) mice.
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Affiliation(s)
- Chia-Yen C Wu
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York
| | - Eileen S Carpenter
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York
| | - Kenneth K Takeuchi
- Department of Cancer Biology, Mayo Clinic Florida, Jacksonville, Florida
| | - Christopher J Halbrook
- Department of Cancer Biology, Mayo Clinic Florida, Jacksonville, Florida; Department of Chemistry, Stony Brook University, Stony Brook, New York
| | - Louise V Peverley
- Department of Cancer Biology, Mayo Clinic Florida, Jacksonville, Florida
| | - Harold Bien
- Division of Hematology/Oncology, Stony Brook University, Stony Brook, New York
| | - Jason C Hall
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York; Department of Cancer Biology, Mayo Clinic Florida, Jacksonville, Florida
| | - Kathleen E DelGiorno
- Department of Cancer Biology, Mayo Clinic Florida, Jacksonville, Florida; Molecular Genetics and Microbiology Graduate Program, Stony Brook University, Stony Brook, New York
| | - Debjani Pal
- Molecular and Cellular Biology Graduate Program, Stony Brook University, Stony Brook, New York
| | - Yan Song
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York
| | - Chanjuan Shi
- Department of Pathology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Richard Z Lin
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York; Medical Service, Northport VA Medical Center, Northport, New York.
| | - Howard C Crawford
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York; Department of Cancer Biology, Mayo Clinic Florida, Jacksonville, Florida.
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