51
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Kawamura M, Umehara D, Odahara Y, Miyake A, Ngo MH, Ohsato Y, Hisasue M, Nakaya MA, Watanabe S, Nishigaki K. AKT capture by feline leukemia virus. Arch Virol 2016; 162:1031-1036. [PMID: 28005210 DOI: 10.1007/s00705-016-3192-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 12/01/2016] [Indexed: 10/20/2022]
Abstract
Oncogene-containing retroviruses are generated by recombination events between viral and cellular sequences, a phenomenon called "oncogene capture". The captured cellular genes, referred to as "v-onc" genes, then acquire new oncogenic properties. We report a novel feline leukemia virus (FeLV), designated "FeLV-AKT", that has captured feline c-AKT1 in feline lymphoma. FeLV-AKT contains a gag-AKT fusion gene that encodes the myristoylated Gag matrix protein and the kinase domain of feline c-AKT1, but not its pleckstrin homology domain. Therefore, it differs structurally from the v-Akt gene of murine retrovirus AKT8. AKT may be involved in the mechanisms underlying malignant diseases in cats.
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Affiliation(s)
- Maki Kawamura
- Laboratory of Molecular Immunology and Infectious Disease, The United Graduate School of Veterinary Science, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, 753-8515, Japan
| | - Daigo Umehara
- Laboratory of Molecular Immunology and Infectious Disease, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, 753-8515, Japan
| | - Yuka Odahara
- Laboratory of Molecular Immunology and Infectious Disease, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, 753-8515, Japan
| | - Ariko Miyake
- Laboratory of Molecular Immunology and Infectious Disease, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, 753-8515, Japan
| | - Minh Ha Ngo
- Laboratory of Molecular Immunology and Infectious Disease, The United Graduate School of Veterinary Science, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, 753-8515, Japan
| | | | - Masaharu Hisasue
- Laboratory of Internal Medicine 2, Veterinary Medicine, Azabu University, 1-17-71, Fuchinobe, Chuou-ku, Sagamihara, Kanagawa, 252-5201, Japan
| | - Masa-Aki Nakaya
- Department of Molecular Biology, Yokohama City University School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan
| | - Shinya Watanabe
- Laboratory of Molecular Immunology and Infectious Disease, The United Graduate School of Veterinary Science, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, 753-8515, Japan
| | - Kazuo Nishigaki
- Laboratory of Molecular Immunology and Infectious Disease, The United Graduate School of Veterinary Science, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, 753-8515, Japan. .,Laboratory of Molecular Immunology and Infectious Disease, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, 753-8515, Japan.
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52
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Zhang MS, Houtman JCD. Human Serum Albumin (HSA) Suppresses the Effects of Glycerol Monolaurate (GML) on Human T Cell Activation and Function. PLoS One 2016; 11:e0165083. [PMID: 27764189 PMCID: PMC5072635 DOI: 10.1371/journal.pone.0165083] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 10/05/2016] [Indexed: 01/30/2023] Open
Abstract
Glycerol monolaurate (GML) is a monoglyceride with well characterized anti-microbial properties. Because of these properties, GML is widely used in food, cosmetics, and personal care products and currently being tested as a therapeutic for menstrual associated toxic shock syndrome, superficial wound infections, and HIV transmission. Recently, we have described that GML potently suppresses select T cell receptor (TCR)-induced signaling events, leading to reduced human T cell effector functions. However, how soluble host factors present in the blood and at sites of infection affect GML-mediated human T cell suppression is unknown. In this study, we have characterized how human serum albumin (HSA) affects GML-induced inhibition of human T cells. We found that HSA and other serum albumins bind to 12 carbon acyl side chain of GML at low micromolar affinities and restores the TCR-induced formation of LAT, PLC-γ1, and AKT microclusters at the plasma membrane. Additionally, HSA reverses GML mediated inhibition of AKT phosphorylation and partially restores cytokine production in GML treated cells. Our data reveal that HSA, one of the most abundant proteins in the human serum and at sites of infections, potently reverses the suppression of human T cells by GML. This suggests that GML-driven human T cell suppression depends upon the local tissue environment, with albumin concentration being a major determinant of GML function.
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Affiliation(s)
- Michael S. Zhang
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, United States of America
| | - Jon C. D. Houtman
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, United States of America
- * E-mail:
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53
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Protein Kinases and Parkinson's Disease. Int J Mol Sci 2016; 17:ijms17091585. [PMID: 27657053 PMCID: PMC5037850 DOI: 10.3390/ijms17091585] [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: 05/30/2016] [Revised: 08/09/2016] [Accepted: 09/01/2016] [Indexed: 01/09/2023] Open
Abstract
Currently, the lack of new drug candidates for the treatment of major neurological disorders such as Parkinson’s disease has intensified the search for drugs that can be repurposed or repositioned for such treatment. Typically, the search focuses on drugs that have been approved and are used clinically for other indications. Kinase inhibitors represent a family of popular molecules for the treatment and prevention of various cancers, and have emerged as strong candidates for such repurposing because numerous serine/threonine and tyrosine kinases have been implicated in the pathobiology of Parkinson’s disease. This review focuses on various kinase-dependent pathways associated with the expression of Parkinson’s disease pathology, and evaluates how inhibitors of these pathways might play a major role as effective therapeutic molecules.
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54
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Kumar A, Abbas W, Colin L, Khan KA, Bouchat S, Varin A, Larbi A, Gatot JS, Kabeya K, Vanhulle C, Delacourt N, Pasquereau S, Coquard L, Borch A, König R, Clumeck N, De Wit S, Rohr O, Rouzioux C, Fulop T, Van Lint C, Herbein G. Tuning of AKT-pathway by Nef and its blockade by protease inhibitors results in limited recovery in latently HIV infected T-cell line. Sci Rep 2016; 6:24090. [PMID: 27076174 PMCID: PMC4831010 DOI: 10.1038/srep24090] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 03/18/2016] [Indexed: 12/14/2022] Open
Abstract
Akt signaling plays a central role in many biological processes, which are key players in human immunodeficiency virus 1 (HIV-1) pathogenesis. We found that Akt interacts with HIV-1 Nef protein. In primary T cells treated with exogenous Nef or acutely infected with Nef-expressing HIV-1 in vitro, Akt became phosphorylated on serine473 and threonine308. In vitro, Akt activation mediated by Nef in T-cells was blocked by HIV protease inhibitors (PI), but not by reverse transcriptase inhibitors (RTI). Ex vivo, we found that the Akt pathway is hyperactivated in peripheral blood lymphocytes (PBLs) from cART naïve HIV-1-infected patients. PBLs isolated from PI-treated patients, but not from RTI-treated patients, exhibited decreased Akt activation, T-cell proliferation and IL-2 production. We found that PI but not RTI can block HIV-1 reactivation in latently infected J-Lat lymphoid cells stimulated with various stimuli. Using luciferase measurement, we further confirmed that Nef-mediated reactivation of HIV-1 from latency in 1G5 cells was blocked by PI parallel to decreased Akt activation. Our results indicate that PI-mediated blockade of Akt activation could impact the HIV-1 reservoir and support the need to further assess the therapeutic use of HIV-1 PI in order to curtail latently infected cells in HIV-1-infected patients.
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Affiliation(s)
- Amit Kumar
- Department of Virology, Pathogens &Inflammation Laboratory, University of Franche-Comté and COMUE Bourgogne Franche-Comté University, UPRES EA4266, SFR FED 4234, CHRU Besançon, Besançon, France
| | - Wasim Abbas
- Department of Virology, Pathogens &Inflammation Laboratory, University of Franche-Comté and COMUE Bourgogne Franche-Comté University, UPRES EA4266, SFR FED 4234, CHRU Besançon, Besançon, France
| | - Laurence Colin
- Laboratory of Molecular Virology, Institut de Biologie et de Médecine Moléculaires (IBMM), Université Libre de Bruxelles (ULB), Gosselies, Belgium
| | - Kashif Aziz Khan
- Department of Virology, Pathogens &Inflammation Laboratory, University of Franche-Comté and COMUE Bourgogne Franche-Comté University, UPRES EA4266, SFR FED 4234, CHRU Besançon, Besançon, France
| | - Sophie Bouchat
- Laboratory of Molecular Virology, Institut de Biologie et de Médecine Moléculaires (IBMM), Université Libre de Bruxelles (ULB), Gosselies, Belgium
| | - Audrey Varin
- Department of Virology, Pathogens &Inflammation Laboratory, University of Franche-Comté and COMUE Bourgogne Franche-Comté University, UPRES EA4266, SFR FED 4234, CHRU Besançon, Besançon, France
| | - Anis Larbi
- Department of Medicine, University of Sherbrooke, Sherbrooke, Canada
| | - Jean-Stéphane Gatot
- Laboratory of Molecular Virology, Institut de Biologie et de Médecine Moléculaires (IBMM), Université Libre de Bruxelles (ULB), Gosselies, Belgium
| | - Kabamba Kabeya
- Department of Infectious Diseases, CHU St-Pierre, ULB, Bruxelles, Belgium
| | - Caroline Vanhulle
- Laboratory of Molecular Virology, Institut de Biologie et de Médecine Moléculaires (IBMM), Université Libre de Bruxelles (ULB), Gosselies, Belgium
| | - Nadège Delacourt
- Laboratory of Molecular Virology, Institut de Biologie et de Médecine Moléculaires (IBMM), Université Libre de Bruxelles (ULB), Gosselies, Belgium
| | - Sébastien Pasquereau
- Department of Virology, Pathogens &Inflammation Laboratory, University of Franche-Comté and COMUE Bourgogne Franche-Comté University, UPRES EA4266, SFR FED 4234, CHRU Besançon, Besançon, France
| | - Laurie Coquard
- Department of Virology, Pathogens &Inflammation Laboratory, University of Franche-Comté and COMUE Bourgogne Franche-Comté University, UPRES EA4266, SFR FED 4234, CHRU Besançon, Besançon, France
| | - Alexandra Borch
- Research Group "Host-Pathogen Interactions", Paul-Ehrlich-Institute, Langen, Germany
| | - Renate König
- Research Group "Host-Pathogen Interactions", Paul-Ehrlich-Institute, Langen, Germany.,Immunity and Pathogenesis Program, Sanford Burnham Prebys Medical Discovery Research Institute, La Jolla, CA; German Center for Infection Research (DZIF), Langen, Germany
| | - Nathan Clumeck
- Department of Infectious Diseases, CHU St-Pierre, ULB, Bruxelles, Belgium
| | - Stephane De Wit
- Department of Infectious Diseases, CHU St-Pierre, ULB, Bruxelles, Belgium
| | - Olivier Rohr
- Institut de Parasitologie et Pathologie Tropicale, University of Strasbourg, Strasbourg, France
| | - Christine Rouzioux
- Department of Virology, Paris University, EA7327 Paris Descartes, APHP Necker Hospital, Paris, France
| | - Tamas Fulop
- Department of Medicine, University of Sherbrooke, Sherbrooke, Canada
| | - Carine Van Lint
- Laboratory of Molecular Virology, Institut de Biologie et de Médecine Moléculaires (IBMM), Université Libre de Bruxelles (ULB), Gosselies, Belgium
| | - Georges Herbein
- Department of Virology, Pathogens &Inflammation Laboratory, University of Franche-Comté and COMUE Bourgogne Franche-Comté University, UPRES EA4266, SFR FED 4234, CHRU Besançon, Besançon, France
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55
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Yamaguchi K, Takanashi T, Nasu K, Tamai K, Mochizuki M, Satoh I, Ine S, Sasaki O, Satoh K, Tanaka N, Harigae H, Sugamura K. Xenotransplantation elicits salient tumorigenicity of adult T-cell leukemia-derived cells via aberrant AKT activation. Cancer Sci 2016; 107:638-43. [PMID: 26928911 PMCID: PMC4970830 DOI: 10.1111/cas.12921] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 02/13/2016] [Accepted: 02/23/2016] [Indexed: 12/16/2022] Open
Abstract
The transplantation of human cancer cells into immunodeficient NOD/SCID/IL‐2Rγcnull (NOG) mice often causes highly malignant cell populations like cancer stem cells to emerge. Here, by serial transplantation in NOG mice, we established two highly tumorigenic adult T‐cell leukemia‐derived cell lines, ST1‐N6 and TL‐Om1‐N8. When transplanted s.c., these cells formed tumors significantly earlier and from fewer initial cells than their parental lines ST1 and TL‐Om1. We found that protein kinase B (AKT) signaling was upregulated in ST1‐N6 and TL‐Om1‐N8 cells, and that this upregulation was due to the decreased expression of a negative regulator, INPP5D. Furthermore, the introduction of a constitutively active AKT mutant expression vector into ST1 cells augmented the tumorigenicity of the cells, whereas treatment with the AKT inhibitor MK‐2206 attenuated the progression of tumors induced by ST1‐N6 cells. Collectively, our results reveal that the AKT signaling pathway plays a critical role in the malignancy of adult T‐cell leukemia‐derived cells.
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Affiliation(s)
- Kazunori Yamaguchi
- Division of Molecular and Cellular Oncology, Miyagi Cancer Center Research Institute, Natori, Japan.,Department of Cancer Science, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Tomoka Takanashi
- Division of Molecular and Cellular Oncology, Miyagi Cancer Center Research Institute, Natori, Japan
| | - Kentaro Nasu
- Division of Molecular and Cellular Oncology, Miyagi Cancer Center Research Institute, Natori, Japan.,Department of Hematology and Rheumatology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Keiichi Tamai
- Department of Cancer Science, Tohoku University Graduate School of Medicine, Sendai, Japan.,Division of Cancer Biology and Therapeutics, Miyagi Cancer Center Research Institute, Natori, Japan
| | - Mai Mochizuki
- Division of Molecular and Cellular Oncology, Miyagi Cancer Center Research Institute, Natori, Japan.,Department of Cancer Science, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Ikuro Satoh
- Department of Cancer Science, Tohoku University Graduate School of Medicine, Sendai, Japan.,Department of Pathology, Miyagi Cancer Center, Natori, Japan
| | - Shoji Ine
- Division of Hematology, Miyagi Cancer Center, Natori, Japan
| | - Osamu Sasaki
- Division of Hematology, Miyagi Cancer Center, Natori, Japan
| | - Kennichi Satoh
- Department of Cancer Science, Tohoku University Graduate School of Medicine, Sendai, Japan.,Division of Cancer Stem Cells, Miyagi Cancer Center Research Institute, Natori, Japan
| | - Nobuyuki Tanaka
- Department of Cancer Science, Tohoku University Graduate School of Medicine, Sendai, Japan.,Division of Cancer Biology and Therapeutics, Miyagi Cancer Center Research Institute, Natori, Japan
| | - Hideo Harigae
- Department of Hematology and Rheumatology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Kazuo Sugamura
- Division of Molecular and Cellular Oncology, Miyagi Cancer Center Research Institute, Natori, Japan
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56
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A Cross-Species Study of PI3K Protein-Protein Interactions Reveals the Direct Interaction of P85 and SHP2. Sci Rep 2016; 6:20471. [PMID: 26839216 PMCID: PMC4738311 DOI: 10.1038/srep20471] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 01/05/2016] [Indexed: 12/14/2022] Open
Abstract
Using a series of immunoprecipitation (IP) – tandem mass spectrometry (LC-MS/MS) experiments and reciprocal BLAST, we conducted a fly-human cross-species comparison of the phosphoinositide-3-kinase (PI3K) interactome in a drosophila S2R+ cell line and several NSCLC and human multiple myeloma cell lines to identify conserved interacting proteins to PI3K, a critical signaling regulator of the AKT pathway. Using H929 human cancer cells and drosophila S2R+ cells, our data revealed an unexpected direct binding of Corkscrew, the drosophila ortholog of the non-receptor protein tyrosine phosphatase type II (SHP2) to the Pi3k21B (p60) regulatory subunit of PI3K (p50/p85 human ortholog) but no association with Pi3k92e, the human ortholog of the p110 catalytic subunit. The p85-SHP2 association was validated in human cell lines, and formed a ternary regulatory complex with GRB2-associated-binding protein 2 (GAB2). Validation experiments with knockdown of GAB2 and Far-Western blots proved the direct interaction of SHP2 with p85, independent of adaptor proteins and transfected FLAG-p85 provided evidence that SHP2 binding on p85 occurred on the SH2 domains. A disruption of the SHP2-p85 complex took place after insulin/IGF1 stimulation or imatinib treatment, suggesting that the direct SHP2-p85 interaction was both independent of AKT activation and positively regulates the ERK signaling pathway.
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57
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Hu S, Wang D, Zhang J, Du M, Cheng Y, Liu Y, Zhang N, Wang D, Wu Y. Mitochondria Related Pathway Is Essential for Polysaccharides Purified from Sparassis crispa Mediated Neuro-Protection against Glutamate-Induced Toxicity in Differentiated PC12 Cells. Int J Mol Sci 2016; 17:ijms17020133. [PMID: 26821016 PMCID: PMC4783876 DOI: 10.3390/ijms17020133] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 12/31/2015] [Accepted: 01/12/2016] [Indexed: 12/19/2022] Open
Abstract
The present study aims to explore the neuro-protective effects of purified Sparassis crispa polysaccharides against l-glutamic acid (l-Glu)-induced differentiated PC12 (DPC12) cell damages and its underlying mechanisms. The Sparassis crispa water extract was purified by a DEAE-52 cellulose anion exchange column and a Sepharose G-100 column. A fraction with a molecular weight of 75 kDa and a diameter of 88.9 nm, entitled SCWEA, was obtained. SCWEA was identified with a triple helix with (1→3)-linked Rha in the backbone, and (1→2) linkages and (1→6) linkages in the side bone. Our results indicated that the pre-treatment of DPC12 cells with SCWEA prior to l-Glu exposure effectively reversed the reduction on cell viability (by 3-(4,5-cimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay) and reduced l-Glu-induced apoptosis (by Hoechst staining). SCWEA decreased the accumulation of intracellular reactive oxygen species, blocked Ca2+ influx and prevented depolarization of the mitochondrial membrane potential in DPC12 cells. Furthermore, SCWEA normalized expression of anti-apoptotic proteins in l-Glu-explored DPC12 cells. These results suggested that SCWEA protects against l-Glu-induced neuronal apoptosis in DPC12 cells and may be a promising candidate for treatment against neurodegenerative disease.
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Affiliation(s)
- Shuang Hu
- School of Life Sciences, Jilin University, Changchun 130012, China.
| | - Di Wang
- School of Life Sciences, Jilin University, Changchun 130012, China.
| | - Junrong Zhang
- School of Life Sciences, Jilin University, Changchun 130012, China.
| | - Mengyan Du
- School of Life Sciences, Jilin University, Changchun 130012, China.
| | - Yingkun Cheng
- School of Life Sciences, Jilin University, Changchun 130012, China.
| | - Yan Liu
- School of Life Sciences, Jilin University, Changchun 130012, China.
| | - Ning Zhang
- School of Life Sciences, Jilin University, Changchun 130012, China.
| | - Di Wang
- School of Life Sciences, Jilin University, Changchun 130012, China.
| | - Yi Wu
- School of Pharmaceutical Science, Jilin University, Changchun 130021, China.
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58
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Kaushik D, Vashistha V, Isharwal S, Sediqe SA, Lin MF. Histone deacetylase inhibitors in castration-resistant prostate cancer: molecular mechanism of action and recent clinical trials. Ther Adv Urol 2015; 7:388-95. [PMID: 26622323 DOI: 10.1177/1756287215597637] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Historically, androgen-deprivation therapy has been the cornerstone for treatment of metastatic prostate cancer. Unfortunately, nearly majority patients with prostate cancer transition to the refractory state of castration-resistant prostate cancer (CRPC). Newer therapeutic agents are needed for treating these CRPC patients that are unresponsive to androgen deprivation and/or chemotherapy. The histone deacetylase (HDAC) family of enzymes limits the expression of genomic regions by improving binding between histones and the DNA backbone. Modulating the role of HDAC enzymes can alter the cell's regulation of proto-oncogenes and tumor suppressor genes, thereby regulating potential neoplastic proliferation. As a result, histone deacetylase inhibitors (HDACi) are now being evaluated for CRPC or chemotherapy-resistant prostate cancer due to their effects on the expression of the androgen receptor gene. In this paper, we review the molecular mechanism and functional target molecules of different HDACi as applicable to CRPC as well as describe recent and current clinical trials involving HDACi in prostate cancer. To date, four HDAC classes comprising 18 isoenzymes have been identified. Recent clinical trials of vorinostat, romidepsin, and panobinostat have provided cautious optimism towards improved outcomes using these novel therapeutic agents for CPRC patients. Nevertheless, no phase III trial has been conducted to cement one of these drugs as an adjunct to androgen-deprivation therapy. Consequently, further investigation is necessary to delineate the benefits and drawbacks of these medications.
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Affiliation(s)
- Dharam Kaushik
- Department of Urology, University of Texas Health Science Center and Cancer Therapy and Research Center, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA
| | - Vishal Vashistha
- Department of Internal Medicine, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Sudhir Isharwal
- Section of Urology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Soud A Sediqe
- Department of Internal Medicine, MetroHealth Medical Center, Cleveland, OH, USA
| | - Ming-Fong Lin
- Section of Urology, and Department of Biochemistry, University of Nebraska Medical Center, Omaha, NE, USA
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59
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Smith SM, Carew NT, Milcarek C. RNA polymerases in plasma cells trav-ELL2 the beat of a different drum. World J Immunol 2015; 5:99-112. [DOI: 10.5411/wji.v5.i3.99] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 08/19/2015] [Accepted: 11/17/2015] [Indexed: 02/05/2023] Open
Abstract
There is a major transformation in gene expression between mature B cells (including follicular, marginal zone, and germinal center cells) and antibody secreting cells (ASCs), i.e., ASCs, (including plasma blasts, splenic plasma cells, and long-lived bone marrow plasma cells). This significant change-over occurs to accommodate the massive amount of secretory-specific immunoglobulin that ASCs make and the export processes itself. It is well known that there is an up-regulation of a small number of ASC-specific transcription factors Prdm1 (B-lymphocyte-induced maturation protein 1), interferon regulatory factor 4, and Xbp1, and the reciprocal down-regulation of Pax5, Bcl6 and Bach2, which maintain the B cell program. Less well appreciated are the major alterations in transcription elongation and RNA processing occurring between B cells and ASCs. The three ELL family members ELL1, 2 and 3 have different protein sequences and potentially distinct cellular roles in transcription elongation. ELL1 is involved in DNA repair and small RNAs while ELL3 was previously described as either testis or stem-cell specific. After B cell stimulation to ASCs, ELL3 levels fall precipitously while ELL1 falls off slightly. ELL2 is induced at least 10-fold in ASCs relative to B cells. All of these changes cause the RNA Polymerase II in ASCs to acquire different properties, leading to differences in RNA processing and histone modifications.
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60
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Caruso M, Zhang X, Ma D, Yang Z, Qi Y, Yi Z. Novel Endogenous, Insulin-Stimulated Akt2 Protein Interaction Partners in L6 Myoblasts. PLoS One 2015; 10:e0140255. [PMID: 26465754 PMCID: PMC4605787 DOI: 10.1371/journal.pone.0140255] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 09/23/2015] [Indexed: 12/28/2022] Open
Abstract
Insulin resistance and Type 2 diabetes are marked by an aberrant response in the insulin signaling network. The phosphoinositide-dependent serine/threonine kinase, Akt2, plays a key role in insulin signaling and glucose uptake, most notably within skeletal muscle. Protein-protein interaction regulates the functional consequence of Akt2 and in turn, Akt2's role in glucose uptake. However, only few insulin-responsive Akt2 interaction partners have been identified in skeletal muscle cells. In the present work, rat L6 myoblasts, a widely used insulin sensitive skeletal muscle cell line, were used to examine endogenous, insulin-stimulated Akt2 protein interaction partners. Akt2 co-immunoprecipitation was coupled with 1D-SDS-PAGE and fractions were analyzed by HPLC-ESI-MS/MS to reveal Akt2 protein-protein interactions. The pull-down assay displayed specificity for the Akt2 isoform; Akt1 and Akt3 unique peptides were not detected. A total of 49 were detected with a significantly increased (47) or decreased (2) association with Akt2 following insulin administration (n = 4; p<0.05). Multiple pathways were identified for the novel Akt2 interaction partners, such as the EIF2 and ubiquitination pathways. These data suggest that multiple new endogenous proteins may associate with Akt2 under basal as well as insulin-stimulated conditions, providing further insight into the insulin signaling network. Data are available via ProteomeXchange with identifier PXD002557.
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Affiliation(s)
- Michael Caruso
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy/Health Sciences, Wayne State University, Detroit, MI, United States of America
| | - Xiangmin Zhang
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy/Health Sciences, Wayne State University, Detroit, MI, United States of America
| | - Danjun Ma
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy/Health Sciences, Wayne State University, Detroit, MI, United States of America
| | - Zhao Yang
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy/Health Sciences, Wayne State University, Detroit, MI, United States of America
| | - Yue Qi
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy/Health Sciences, Wayne State University, Detroit, MI, United States of America
| | - Zhengping Yi
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy/Health Sciences, Wayne State University, Detroit, MI, United States of America
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61
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Chen XL, Serrano D, Mayhue M, Hoebe K, Ilangumaran S, Ramanathan S. GIMAP5 Deficiency Is Associated with Increased AKT Activity in T Lymphocytes. PLoS One 2015; 10:e0139019. [PMID: 26440416 PMCID: PMC4595448 DOI: 10.1371/journal.pone.0139019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 09/07/2015] [Indexed: 01/05/2023] Open
Abstract
Long-term survival of T lymphocytes in quiescent state is essential to maintain their cell numbers in secondary lymphoid organs. In mice and in rats, the loss of functional GTPase of the immune associated nucleotide binding protein 5 (GIMAP5) causes peripheral T lymphopenia due to spontaneous death of T cells. The underlying mechanism responsible for the disruption of quiescence in Gimap5 deficient T cells remains largely unknown. In this study, we show that loss of functional Gimap5 results in increased basal activation of mammalian target of rapamycin (mTOR), independent of protein phosphatase 2A (PP2A) or AMP-activated protein kinase (AMPK). Our results suggest that the constitutive activation of the phosphoinositide 3-kinase (PI3K) pathway may be one of the consequences of the absence of functional GIMAP5.
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Affiliation(s)
- Xi-Lin Chen
- Immunology Division, Department of Pediatrics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, J1H 5N4, Québec, Canada
| | - Daniel Serrano
- Immunology Division, Department of Pediatrics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, J1H 5N4, Québec, Canada
| | - Marian Mayhue
- Immunology Division, Department of Pediatrics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, J1H 5N4, Québec, Canada
| | - Kasper Hoebe
- Department of Pediatrics, Division of Cellular and Molecular Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, United States of America
| | - Subburaj Ilangumaran
- Immunology Division, Department of Pediatrics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, J1H 5N4, Québec, Canada
- Centre de Recherche Clinique, Université de Sherbrooke, Sherbrooke, J1H 5N4, Québec, Canada
| | - Sheela Ramanathan
- Immunology Division, Department of Pediatrics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, J1H 5N4, Québec, Canada
- Centre de Recherche Clinique, Université de Sherbrooke, Sherbrooke, J1H 5N4, Québec, Canada
- * E-mail:
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Chang RCA, Shi L, Huang CCY, Kim AJ, Ko ML, Zhou B, Ko GYP. High-Fat Diet-Induced Retinal Dysfunction. Invest Ophthalmol Vis Sci 2015; 56:2367-80. [PMID: 25788653 DOI: 10.1167/iovs.14-16143] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
PURPOSE The purpose of this study was to investigate the impact of obesity-induced prediabetes/early diabetes on the retina to provide new evidence on the pathogenesis of type 2 diabetes-associated diabetic retinopathy (DR). METHODS A high-fat diet (HFD)-induced obesity mouse model (male C57BL/6J) was used in this study. At the end of the 12-week HFD feeding regimen, mice were evaluated for glucose and insulin tolerance, and retinal light responses were recorded by electroretinogram (ERG). Western immunoblot and immunohistochemical staining were used to determine changes in elements regulating calcium homeostasis between HFD and control retinas, as well as unstained human retinal sections from DR patients and age-appropriate controls. RESULTS Compared to the control, the scotopic and photopic ERGs from HFD mice were decreased. There were significant decreases in molecules related to cell signaling, calcium homeostasis, and glucose metabolism from HFD retinas, including phosphorylated protein kinase B (pAKT), glucose transporter 4, L-type voltage-gated calcium channel (L-VGCC), and plasma membrane calcium ATPase (PMCA). Similar changes for pAKT, PMCA, and L-VGCC were also observed in human retinal sections from DR patients. CONCLUSIONS Obesity-induced hyperglycemic and prediabetic/early diabetic conditions caused detrimental impacts on retinal light sensitivities and health. The decrease of the ERG components in early diabetes reflects the decreased neuronal activity of retinal light responses, which may be caused by a decrease in neuronal calcium signaling. Since PI3K-AKT is important in regulating calcium homeostasis and neural survival, maintaining proper PI3K-AKT signaling in early diabetes or at the prediabetic stage might be a new strategy for DR prevention.
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Affiliation(s)
- Richard Cheng-An Chang
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States
| | - Liheng Shi
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States
| | - Cathy Chia-Yu Huang
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States
| | - Andy Jeesu Kim
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States
| | - Michael L Ko
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States
| | - Beiyan Zhou
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States
| | - Gladys Y-P Ko
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States 3Texas A&M Institute of Neuroscience, Texas A&M University, College Station, Texas, Unite
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63
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Akt kinase C-terminal modifications control activation loop dephosphorylation and enhance insulin response. Biochem J 2015. [PMID: 26201515 DOI: 10.1042/bj20150325] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The Akt protein kinase, also known as protein kinase B, plays key roles in insulin receptor signalling and regulates cell growth, survival and metabolism. Recently, we described a mechanism to enhance Akt phosphorylation that restricts access of cellular phosphatases to the Akt activation loop (Thr(308) in Akt1 or protein kinase B isoform alpha) in an ATP-dependent manner. In the present paper, we describe a distinct mechanism to control Thr(308) dephosphorylation and thus Akt deactivation that depends on intramolecular interactions of Akt C-terminal sequences with its kinase domain. Modifications of amino acids surrounding the Akt1 C-terminal mTORC2 (mammalian target of rapamycin complex 2) phosphorylation site (Ser(473)) increased phosphatase resistance of the phosphorylated activation loop (pThr(308)) and amplified Akt phosphorylation. Furthermore, the phosphatase-resistant Akt was refractory to ceramide-dependent dephosphorylation and amplified insulin-dependent Thr(308) phosphorylation in a regulated fashion. Collectively, these results suggest that the Akt C-terminal hydrophobic groove is a target for the development of agents that enhance Akt phosphorylation by insulin.
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PI3K-C2γ is a Rab5 effector selectively controlling endosomal Akt2 activation downstream of insulin signalling. Nat Commun 2015; 6:7400. [PMID: 26100075 PMCID: PMC4479417 DOI: 10.1038/ncomms8400] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 05/06/2015] [Indexed: 01/09/2023] Open
Abstract
In the liver, insulin-mediated activation of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway is at the core of metabolic control. Multiple PI3K and Akt isoenzymes are found in hepatocytes and whether isoform-selective interplays exist is currently unclear. Here we report that insulin signalling triggers the association of the liver-specific class II PI3K isoform γ (PI3K-C2γ) with Rab5-GTP, and its recruitment to Rab5-positive early endosomes. In these vesicles, PI3K-C2γ produces a phosphatidylinositol-3,4-bisphosphate pool specifically required for delayed and sustained endosomal Akt2 stimulation. Accordingly, loss of PI3K-C2γ does not affect insulin-dependent Akt1 activation as well as S6K and FoxO1-3 phosphorylation, but selectively reduces Akt2 activation, which specifically inhibits glycogen synthase activity. As a consequence, PI3K-C2γ-deficient mice display severely reduced liver accumulation of glycogen and develop hyperlipidemia, adiposity as well as insulin resistance with age or after consumption of a high-fat diet. Our data indicate PI3K-C2γ supports an isoenzyme-specific forking of insulin-mediated signal transduction to an endosomal pool of Akt2, required for glucose homeostasis. The kinase PI3K is crucial for insulin signalling in the liver but the roles of individual PI3K isoforms are largely unclear. Using mice that lack class II PI3K isoform γ (PI3K-C2γ), the authors here show that PI3K-C2γ selectively activates endosomal Akt2 by regulating the localized production of PIP2.
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65
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Abstract
Phosphoinositide 3-kinases (PI3Ks) are central regulators of cellular responses to extracellular stimuli, and are involved in growth, proliferation, migration, and metabolism. The Class I PI3Ks are activated by Receptor Tyrosine Kinases (RTKs) or G Protein-Coupled Receptors (GPCRs), and their signaling is commonly deregulated in disease conditions. Among the class I PI3Ks, the p110β isoform is unique in being activated by both RTKs and GPCRs, and its ability to bind Rho-GTPases and Rab5. Recent studies have characterized these p110β interacting partners, defining the binding mechanisms and regulation, and thus provide insight into the function of this kinase in physiology and disease. This review summarizes the developments in p110β research, focusing on the interacting partners and their role in p110β-mediated signaling.
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Affiliation(s)
- Hashem A Dbouk
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390
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66
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Xue G, Zippelius A, Wicki A, Mandala M, Tang F, Massi D, Hemmings BA. Integrated Akt/PKB Signaling in Immunomodulation and Its Potential Role in Cancer Immunotherapy. J Natl Cancer Inst 2015; 107:djv171. [DOI: 10.1093/jnci/djv171] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 05/22/2015] [Indexed: 12/17/2022] Open
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67
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Wiese KE, Haikala HM, von Eyss B, Wolf E, Esnault C, Rosenwald A, Treisman R, Klefström J, Eilers M. Repression of SRF target genes is critical for Myc-dependent apoptosis of epithelial cells. EMBO J 2015; 34:1554-71. [PMID: 25896507 PMCID: PMC4474530 DOI: 10.15252/embj.201490467] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 03/28/2015] [Accepted: 03/30/2015] [Indexed: 12/22/2022] Open
Abstract
Oncogenic levels of Myc expression sensitize cells to multiple apoptotic stimuli, and this protects long-lived organisms from cancer development. How cells discriminate physiological from supraphysiological levels of Myc is largely unknown. Here, we show that induction of apoptosis by Myc in breast epithelial cells requires association of Myc with Miz1. Gene expression and ChIP-Sequencing experiments show that high levels of Myc invade target sites that lack consensus E-boxes in a complex with Miz1 and repress transcription. Myc/Miz1-repressed genes encode proteins involved in cell adhesion and migration and include several integrins. Promoters of repressed genes are enriched for binding sites of the serum-response factor (SRF). Restoring SRF activity antagonizes Myc repression of SRF target genes, attenuates Myc-induced apoptosis, and reverts a Myc-dependent decrease in Akt phosphorylation and activity, a well-characterized suppressor of Myc-induced apoptosis. We propose that high levels of Myc engage Miz1 in repressive DNA binding complexes and suppress an SRF-dependent transcriptional program that supports survival of epithelial cells.
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Affiliation(s)
- Katrin E Wiese
- Biocenter Theodor Boveri Institute University of Würzburg, Würzburg, Germany
| | - Heidi M Haikala
- Faculty of Medicine, Cancer Cell Circuitry Laboratory, Translational Cancer Biology Research Program and Institute of Biomedicine Biomedicum Helsinki University of Helsinki, Helsinki, Finland
| | - Björn von Eyss
- Biocenter Theodor Boveri Institute University of Würzburg, Würzburg, Germany
| | - Elmar Wolf
- Biocenter Theodor Boveri Institute University of Würzburg, Würzburg, Germany
| | - Cyril Esnault
- Cancer Research UK London Research Institute Lincoln's Inn Fields Laboratories Transcription Laboratory, London, UK
| | - Andreas Rosenwald
- Institute of Pathology University of Würzburg, Würzburg, Germany Comprehensive Cancer Center Mainfranken University of Würzburg, Würzburg, Germany
| | - Richard Treisman
- Cancer Research UK London Research Institute Lincoln's Inn Fields Laboratories Transcription Laboratory, London, UK
| | - Juha Klefström
- Faculty of Medicine, Cancer Cell Circuitry Laboratory, Translational Cancer Biology Research Program and Institute of Biomedicine Biomedicum Helsinki University of Helsinki, Helsinki, Finland
| | - Martin Eilers
- Biocenter Theodor Boveri Institute University of Würzburg, Würzburg, Germany Comprehensive Cancer Center Mainfranken University of Würzburg, Würzburg, Germany
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68
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pGlcNAc Nanofiber Treatment of Cutaneous Wounds Stimulate Increased Tensile Strength and Reduced Scarring via Activation of Akt1. PLoS One 2015; 10:e0127876. [PMID: 25955155 PMCID: PMC4425470 DOI: 10.1371/journal.pone.0127876] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 04/21/2015] [Indexed: 11/30/2022] Open
Abstract
Treatment of cutaneous wounds with poly-N-acetyl-glucosamine containing nanofibers (pGlcNAc), a novel polysaccharide material derived from a marine diatom, results in increased wound closure, antibacterial activities and innate immune responses. We have shown that Akt1 plays a central role in the regulation of these activities. Here, we show that pGlcNAc treatment of cutaneous wounds results in a smaller scar that has increased tensile strength and elasticity. pGlcNAc treated wounds exhibit decreased collagen content, increased collagen organization and decreased myofibroblast content. A fibrin gel assay was used to assess the regulation of fibroblast alignment in vitro. In this assay, fibrin lattice is formed with two pins that provide focal points upon which the gel can exert force as the cells align from pole to pole. pGlcNAc stimulation of embedded fibroblasts results in cellular alignment as compared to untreated controls, by a process that is Akt1 dependent. We show that Akt1 is required in vivo for the pGlcNAc-induced increased tensile strength and elasticity. Taken together, our findings suggest that pGlcNAc nanofibers stimulate an Akt1 dependent pathway that results in the proper alignment of fibroblasts, decreased scarring, and increased tensile strength during cutaneous wound healing.
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69
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Mok KW, Chen H, Lee WM, Cheng CY. rpS6 regulates blood-testis barrier dynamics through Arp3-mediated actin microfilament organization in rat sertoli cells. An in vitro study. Endocrinology 2015; 156:1900-13. [PMID: 25714812 PMCID: PMC4398761 DOI: 10.1210/en.2014-1791] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In the seminiferous epithelium of rat testes, preleptotene spermatocytes residing in the basal compartment are transported across the blood-testis barrier (BTB) to enter the adluminal compartment at stage VIII of the epithelial cycle. This process involves redistribution of tight junction (TJ) proteins via reorganization of actin cytoskeleton in Sertoli cells that serves as attachment site for adhesion protein complexes. Ribosomal protein S6 (rpS6), a downstream molecule of mTORC1 (mammalian target of rapamycin complex 1), participates in this process via a yet-to-be defined mechanism. Here, we constructed an rpS6 quadruple phosphomimetic mutant by converting Ser residues at 235, 236, 240, and 244 to Glu via site-directed mutagenesis, making this mutant constitutively active. When this rpS6 mutant was overexpressed in Sertoli cells cultured in vitro with an established TJ barrier mimicking the BTB in vivo, it perturbed the TJ permeability by down-regulating and redistributing TJ proteins at the cell-cell interface. These changes are mediated by a reorganization of actin microfilaments, which was triggered by a redistribution of activated actin-related protein 3 (Arp3) as well as changes in Arp3-neuronal Wiskott-Aldrich Syndrome protein (N-WASP) interaction. This in turn induced reorganization of actin microfilaments, converting them from a "bundled" to an "unbundled/branched" configuration, concomitant with a reduced actin bundling activity, thereby destabilizing the TJ-barrier function. These changes were mediated by Akt (transforming oncogene of v-akt), because an Akt knockdown by RNA interference was able to mimic the phenotypes of rpS6 mutant overexpression at the Sertoli cell BTB. In summary, this study illustrates a mechanism by which mTORC1 signal complex regulates BTB function through rpS6 downstream by modulating actin organization via the Arp2/3 complex, which may be applicable to other tissue barriers.
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Affiliation(s)
- Ka-Wai Mok
- The Mary M. Wohlford Laboratory for Male Contraceptive Research (K.-W.M., H.C., C.Y.C.), Center for Biomedical Research, Population Council, New York, New York 10065; and School of Biological Sciences (W.M.L.), University of Hong Kong, Hong Kong, China
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Naguib A, Bencze G, Cho H, Zheng W, Tocilj A, Elkayam E, Faehnle CR, Jaber N, Pratt CP, Chen M, Zong WX, Marks MS, Joshua-Tor L, Pappin DJ, Trotman LC. PTEN functions by recruitment to cytoplasmic vesicles. Mol Cell 2015; 58:255-68. [PMID: 25866245 DOI: 10.1016/j.molcel.2015.03.011] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 01/18/2015] [Accepted: 03/05/2015] [Indexed: 12/21/2022]
Abstract
PTEN is proposed to function at the plasma membrane, where receptor tyrosine kinases are activated. However, the majority of PTEN is located throughout the cytoplasm. Here, we show that cytoplasmic PTEN is distributed along microtubules, tethered to vesicles via phosphatidylinositol 3-phosphate (PI(3)P), the signature lipid of endosomes. We demonstrate that the non-catalytic C2 domain of PTEN specifically binds PI(3)P through the CBR3 loop. Mutations render this loop incapable of PI(3)P binding and abrogate PTEN-mediated inhibition of PI 3-kinase/AKT signaling. This loss of function is rescued by fusion of the loop mutant PTEN to FYVE, the canonical PI(3)P binding domain, demonstrating the functional importance of targeting PTEN to endosomal membranes. Beyond revealing an upstream activation mechanism of PTEN, our data introduce the concept of PI 3-kinase signal activation on the vast plasma membrane that is contrasted by PTEN-mediated signal termination on the small, discrete surfaces of internalized vesicles.
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Affiliation(s)
- Adam Naguib
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Gyula Bencze
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Hyejin Cho
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Wu Zheng
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Ante Tocilj
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA; W. M. Keck Structural Biology Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Elad Elkayam
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA; W. M. Keck Structural Biology Laboratory, Cold Spring Harbor, NY 11724, USA; Howard Hughes Medical Institute, Cold Spring Harbor, NY 11724, USA
| | - Christopher R Faehnle
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA; W. M. Keck Structural Biology Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Nadia Jaber
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11794, USA
| | | | - Muhan Chen
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Wei-Xing Zong
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Michael S Marks
- Department of Pathology & Laboratory of Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Pathology & Laboratory of Medicine and Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Leemor Joshua-Tor
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA; W. M. Keck Structural Biology Laboratory, Cold Spring Harbor, NY 11724, USA; Howard Hughes Medical Institute, Cold Spring Harbor, NY 11724, USA
| | - Darryl J Pappin
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Lloyd C Trotman
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
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Bischoff A, Bayerlová M, Strotbek M, Schmid S, Beissbarth T, Olayioye MA. A global microRNA screen identifies regulators of the ErbB receptor signaling network. Cell Commun Signal 2015; 13:5. [PMID: 25630670 PMCID: PMC4314810 DOI: 10.1186/s12964-015-0084-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 01/12/2015] [Indexed: 01/07/2023] Open
Abstract
Background The growth factor heregulin (HRG) potently stimulates epithelial cell survival and proliferation through the binding of its cognate receptor ErbB3 (also known as HER3). ErbB3-dependent signal transmission relies on the dimerization partner ErbB2, a receptor tyrosine kinase that is frequently overexpressed and/or amplified in breast cancer cells. Substantial evidence suggests that deregulated ErbB3 expression also contributes to the transformed phenotype of breast cancer cells. Results By genome-wide screening, we identify 43 microRNAs (miRNAs) that specifically impact HRG-induced activation of the PI3K-Akt pathway. Bioinformatic analysis combined with experimental validation reveals a highly connected molecular miRNA-gene interaction network particularly for the negative screen hits. For selected miRNAs, namely miR-149, miR-148b, miR-326, and miR-520a-3p, we demonstrate the simultaneous downregulation of the ErbB3 receptor and multiple downstream signaling molecules, explaining their efficient dampening of HRG responses and ascribing to these miRNAs potential context-dependent tumor suppressive functions. Conclusions Given the contribution of HRG signaling and the PI3K-Akt pathway in particular to tumorigenesis, this study not only provides mechanistic insight into the function of miRNAs but also has implications for future clinical applications. Electronic supplementary material The online version of this article (doi:10.1186/s12964-015-0084-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | - Monilola A Olayioye
- Institute of Cell Biology and Immunology, University of Stuttgart, Allmandring 31, Stuttgart, 70569, Germany.
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Boland BB, Alarcón C, Ali A, Rhodes CJ. Monomethylated-adenines potentiate glucose-induced insulin production and secretion via inhibition of phosphodiesterase activity in rat pancreatic islets. Islets 2015; 7:e1073435. [PMID: 26404841 PMCID: PMC4878263 DOI: 10.1080/19382014.2015.1073435] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Monomethyladenines have effects on DNA repair, G-protein-coupled receptor antagonism and autophagy. In islet ß-cells, 3-methyladenine (3-MA) has been implicated in DNA-repair and autophagy, but its mechanism of action is unclear. Here, the effect of monomethylated adenines was examined in rat islets. 3-MA, N6-methyladenine (N6-MA) and 9-methyladenine (9-MA), but not 1- or 7-monomethylated adenines, specifically potentiated glucose-induced insulin secretion (3-4 fold; p ≤ 0.05) and proinsulin biosynthesis (∼2-fold; p ≤ 0.05). Using 3-MA as a 'model' monomethyladenine, it was found that 3-MA augmented [cAMP]i accumulation (2-3 fold; p ≤ 0.05) in islets within 5 minutes. The 3-, N6- and 9-MA also enhanced glucose-induced phosphorylation of the cAMP/protein kinase-A (PKA) substrate cAMP-response element binding protein (CREB). Treatment of islets with pertussis or cholera toxin indicated 3-MA mediated elevation of [cAMP]i was not mediated via G-protein-coupled receptors. Also, 3-MA did not compete with 9-cyclopentyladenine (9-CPA) for adenylate cyclase inhibition, but did for the pan-inhibitor of phosphodiesterase (PDE), 3-isobutyl-1-methylxanthine (IBMX). Competitive inhibition experiments with PDE-isoform specific inhibitors suggested 3-MA to have a preference for PDE4 in islet ß-cells, but this was likely reflective of PDE4 being the most abundant PDE isoform in ß-cells. In vitro enzyme assays indicated that 3-, N6- and 9-MA were capable of inhibiting most PDE isoforms found in ß-cells. Thus, in addition to known inhibition of phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3'K)/m Target of Rapamycin (mTOR) signaling, 3-MA also acts as a pan-phosphodiesterase inhibitor in pancreatic ß-cells to elevate [cAMP]i and then potentiate glucose-induced insulin secretion and production in parallel.
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Affiliation(s)
- Brandon B Boland
- The Kovler Diabetes Center; Department of Medicine; Section on Endocrinology, Diabetes & Metabolism; The University of Chicago; Chicago, IL USA
| | - Cristina Alarcón
- The Kovler Diabetes Center; Department of Medicine; Section on Endocrinology, Diabetes & Metabolism; The University of Chicago; Chicago, IL USA
| | - Almas Ali
- The Kovler Diabetes Center; Department of Medicine; Section on Endocrinology, Diabetes & Metabolism; The University of Chicago; Chicago, IL USA
| | - Christopher J Rhodes
- The Kovler Diabetes Center; Department of Medicine; Section on Endocrinology, Diabetes & Metabolism; The University of Chicago; Chicago, IL USA
- Correspondence to: Christopher J Rhodes PhD;
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Duan H, Qu L, Shou C. Activation of EGFR-PI3K-AKT signaling is required for Mycoplasma hyorhinis-promoted gastric cancer cell migration. Cancer Cell Int 2014; 14:135. [PMID: 25505372 PMCID: PMC4262230 DOI: 10.1186/s12935-014-0135-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 11/20/2014] [Indexed: 01/26/2023] Open
Abstract
Persistent infection of Mycoplasma hyorhinis (M. hyorhinis) was associated with gastric cancer cell migration and invasion, but the mechanisms were not well understood. Herein, we found that M. hyorhinis activated phosphoinositide 3-kinase (PI3K)-AKT signaling axis in gastric cancer cell lines. Epidermal growth factor receptor (EGFR) was upstream of PI3K-AKT signaling in the context of M. hyorhinis infection, because phosphorylation of AKT Serine 473 was almost completely attenuated by the EGFR inhibitor AG1478 or by EGFR knockdown. Phosphorylation of AKT S473 induced by M. hyorhinis infection was also abolished by PI3K inhibitor wortmannin. Furthermore, we found that p37, a membrane protein of M. hyorhinis, could also promote M. hyorhinis-induced PI3K-AKT signaling activation and cell migration. In addition, pre-treatment with AG1478 or wortmannin significantly inhibited cell migration induced by M. hyorhinis infection or p37 treatment. In conclusion, EGFR-PI3K-AKT signaling plays an important role in M. hyorhinis-promoted cell migration in gastric cancer cells, thus providing a clue to the pathogenesis of M. hyorhinis in gastric cancer.
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Affiliation(s)
- Hongying Duan
- Department of Biochemistry and Molecular Biology, Peking University Cancer Hospital & Institute, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), 52 Fucheng Road, Beijing, 100142 China
| | - Like Qu
- Department of Biochemistry and Molecular Biology, Peking University Cancer Hospital & Institute, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), 52 Fucheng Road, Beijing, 100142 China
| | - Chengchao Shou
- Department of Biochemistry and Molecular Biology, Peking University Cancer Hospital & Institute, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), 52 Fucheng Road, Beijing, 100142 China
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Zhang J, Chen T, Mao Q, Lin J, Jia J, Li S, Xiong W, Lin Y, Liu Z, Liu X, Zhao H, Wang G, Zheng D, Qiu S, Ge J. PDGFR-β-activated ACK1-AKT signaling promotes glioma tumorigenesis. Int J Cancer 2014; 136:1769-80. [PMID: 25257795 DOI: 10.1002/ijc.29234] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 09/04/2014] [Accepted: 09/10/2014] [Indexed: 12/15/2022]
Abstract
Aberrant PDGF-PDGFR signaling and its effects on downstream effectors have been implicated in glioma development. A crucial AKT regulator, ACK1 (TNK2) has been shown to be a downstream mediator of PDGF signaling; however, the exact underlying mechanisms in gliomas remain elusive. Here, we report that in glioma cells, PDGFR-β activation enhanced the interaction between ACK1 and AKT, resulting in AKT activation. PDGF treatment consistently promoted the formation of complexes containing PDGFR-β and ACK1. Mutational analysis suggested that Y635 of ACK1 is a PDGFR-β phosphorylation site and that the ACK1 Y635F mutant abrogated the sequential activation of AKT. Moreover, PDK1 interacted with ACK1 during PDGF stimulation, which is required for the binding of ACK1 to PDGFR-β. Further mutational analysis showed that T325 of ACK1 was crucial for the ACK1 and PDK1 interaction. ACK1 Y635F or T325A mutants abolished PDGFR-β-induced AKT activation, the subsequent nuclear translocation of β-catenin and the expression of cyclin D1. Glioma cell cycle progression, proliferation and tumorigenesis were accordingly blocked by ACK1 Y635F or T325A. In glioblastoma multiforme samples from 51 patients, increased ACK1 tyrosine phosphorylation correlated with upregulated PDGFR-β activity and AKT activation. Taken together, our data demonstrate that ACK1 plays a pivotal role in PDGF-PDGFR-induced AKT signaling in glioma tumorigenesis. This knowledge contributes to our understanding of glioma progression and may facilitate the identification of novel therapeutic targets for future glioma treatment.
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Affiliation(s)
- Jiannan Zhang
- Operation Room, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiaotong University, Shanghai, 200127, People's Republic of China
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75
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Mok KW, Mruk DD, Cheng CY. rpS6 regulates blood-testis barrier dynamics through Akt-mediated effects on MMP-9. J Cell Sci 2014; 127:4870-82. [PMID: 25217631 DOI: 10.1242/jcs.152231] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Mammalian target of rapamycin complex 1 (mTORC1) is an emerging regulator of blood-tissue barriers that utilizes ribosomal protein S6 (rpS6) as the downstream signaling molecule. To explore the role of rpS6 in blood-testis barrier (BTB) function, a constitutively active quadruple rpS6 phosphomimetic mutant was constructed in mammalian expression vector and overexpressed in Sertoli cells cultured in vitro that mimicked the BTB in vivo. Using this quadruple phosphomimetic mutant, phosphorylated (p)-rpS6 was shown to disrupt IGF-1/insulin signaling, thereby abolishing Akt phosphorylation, which led to an induction of MMP-9. This increase in MMP-9 secretion perturbed the Sertoli cell tight junction permeability barrier by proteolysis-mediated downregulation of tight junction proteins at the BTB. These findings were confirmed by the use of a specific MMP-9 inhibitor that blocked the disruption of the tight junction permeability barrier by the rpS6 mutant. Additionally, RNA interference (RNAi)-mediated Akt silencing was able to mimic the results of rpS6 mutant overexpression in Sertoli cells, further confirming this p-rpS6-Akt-MMP-9 signaling pathway. In conclusion, these data support a new concept of mTORC1-mediated BTB regulation, that is possibly also applicable to other blood-tissue barriers.
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Affiliation(s)
- Ka-Wai Mok
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Avenue, New York, NY 10065, USA
| | - Dolores D Mruk
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Avenue, New York, NY 10065, USA
| | - C Yan Cheng
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Avenue, New York, NY 10065, USA
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76
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Cariaga-Martínez AE, Cortés I, García E, Pérez-García V, Pajares MJ, Idoate MA, Redondo-Muñóz J, Antón IM, Carrera AC. Phosphoinositide 3-kinase p85beta regulates invadopodium formation. Biol Open 2014; 3:924-36. [PMID: 25217619 PMCID: PMC4197441 DOI: 10.1242/bio.20148185] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The acquisition of invasiveness is characteristic of tumor progression. Numerous genetic changes are associated with metastasis, but the mechanism by which a cell becomes invasive remains unclear. Expression of p85β, a regulatory subunit of phosphoinositide-3-kinase, markedly increases in advanced carcinoma, but its mode of action is unknown. We postulated that p85β might facilitate cell invasion. We show that p85β localized at cell adhesions in complex with focal adhesion kinase and enhanced stability and maturation of cell adhesions. In addition, p85β induced development at cell adhesions of an F-actin core that extended several microns into the cell z-axis resembling the skeleton of invadopodia. p85β lead to F-actin polymerization at cell adhesions by recruiting active Cdc42/Rac at these structures. In accordance with p85β function in invadopodium-like formation, p85β levels increased in metastatic melanoma and p85β depletion reduced invadopodium formation and invasion. These results show that p85β enhances invasion by inducing cell adhesion development into invadopodia-like structures explaining the metastatic potential of tumors with increased p85β levels.
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Affiliation(s)
- Ariel E Cariaga-Martínez
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Madrid E-28049, Spain
| | - Isabel Cortés
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Madrid E-28049, Spain
| | - Esther García
- Department of Molecular and Cell Biology, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Madrid E-28049, Spain
| | - Vicente Pérez-García
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Madrid E-28049, Spain
| | - María J Pajares
- Biomarkers Laboratory, Division of Oncology, Center for Applied Biomedical Research (CIMA), University of Navarra, Pamplona E-31008, Spain
| | - Miguel A Idoate
- Pathology Department, Hospital Clinic of Navarra, University of Navarra, Pamplona, E-31008, Spain
| | - Javier Redondo-Muñóz
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Madrid E-28049, Spain
| | - Inés M Antón
- Department of Molecular and Cell Biology, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Madrid E-28049, Spain
| | - Ana C Carrera
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Madrid E-28049, Spain
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Fucosylated Chondroitin Sulfate From Sea Cucumber Improves Glucose Metabolism and Activates Insulin Signaling in the Liver of Insulin-Resistant Mice. J Med Food 2014; 17:749-57. [DOI: 10.1089/jmf.2013.2924] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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Salamon RS, Backer JM. Phosphatidylinositol-3,4,5-trisphosphate: tool of choice for class I PI 3-kinases. Bioessays 2014; 35:602-11. [PMID: 23765576 DOI: 10.1002/bies.201200176] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Class I PI 3-kinases signal by producing the signaling lipid phosphatidylinositol(3,4,5) trisphosphate, which in turn acts by recruiting downstream effectors that contain specific lipid-binding domains. The class I PI 3-kinases comprise four distinct catalytic subunits linked to one of seven different regulatory subunits. All the class I PI 3-kinases produce the same signaling lipid, PIP3, and the different isoforms have overlapping expression patterns and are coupled to overlapping sets of upstream activators. Nonetheless, studies in cultured cells and in animals have demonstrated that the different isoforms are coupled to distinct ranges of downstream responses. This review focuses on the mechanisms by which the production of a common product, PIP3, can produce isoform-specific signaling by PI 3-kinases.
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Affiliation(s)
- Rachel Schnur Salamon
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
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79
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Role of receptor tyrosine kinases and their ligands in glioblastoma. Cells 2014; 3:199-235. [PMID: 24709958 PMCID: PMC4092852 DOI: 10.3390/cells3020199] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 03/12/2014] [Accepted: 03/21/2014] [Indexed: 01/04/2023] Open
Abstract
Glioblastoma multiforme is the most frequent, aggressive and fatal type of brain tumor. Glioblastomas are characterized by their infiltrating nature, high proliferation rate and resistance to chemotherapy and radiation. Recently, oncologic therapy experienced a rapid evolution towards “targeted therapy,” which is the employment of drugs directed against particular targets that play essential roles in proliferation, survival and invasiveness of cancer cells. A number of molecules involved in signal transduction pathways are used as molecular targets for the treatment of various tumors. In fact, inhibitors of these molecules have already entered the clinic or are undergoing clinical trials. Cellular receptors are clear examples of such targets and in the case of glioblastoma multiforme, some of these receptors and their ligands have become relevant. In this review, the importance of glioblastoma multiforme in signaling pathways initiated by extracellular tyrosine kinase receptors such as EGFR, PDGFR and IGF-1R will be discussed. We will describe their ligands, family members, structure, activation mechanism, downstream molecules, as well as the interaction among these pathways. Lastly, we will provide an up-to-date review of the current targeted therapies in cancer, in particular glioblastoma that employ inhibitors of these pathways and their benefits.
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80
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Lee JK, Chung HJ, Fischer L, Fischer J, Gonzalez FJ, Jeong H. Human placental lactogen induces CYP2E1 expression via PI 3-kinase pathway in female human hepatocytes. Drug Metab Dispos 2014; 42:492-9. [PMID: 24408518 PMCID: PMC3965907 DOI: 10.1124/dmd.113.055384] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 01/08/2014] [Indexed: 12/29/2022] Open
Abstract
The state of pregnancy is known to alter hepatic drug metabolism. Hormones that rise during pregnancy are potentially responsible for the changes. Here we report the effects of prolactin (PRL), placental lactogen (PL), and growth hormone variant (GH-v) on expression of major hepatic cytochromes P450 expression and a potential molecular mechanism underlying CYP2E1 induction by PL. In female human hepatocytes, PRL and GH-v showed either no effect or small and variable effects on mRNA expression of CYP1A2, 2A6, 2B6, 2C9, 2C19, 2D6, 2E1, 3A4, and 3A5. On the other hand, PL increased expression level of CYP2E1 mRNA with corresponding increases in CYP2E1 protein and activity levels. Results from hepatocytes and HepaRG cells indicate that PL does not affect the expression or activity of HNF1α, the known transcriptional activator of basal CYP2E1 expression. Furthermore, transient transfection studies and Western blot results showed that STAT signaling, the previously known mediator of PL actions in certain tissues, does not play a role in CYP2E1 induction by PL. A chemical inhibitor of PI3-kinase signaling significantly repressed the CYP2E1 induction by PL in human hepatocytes, suggesting involvement of PI3-kinase pathway in CYP2E1 regulation by PL. CYP2E1-humanized mice did not exhibit enhanced CYP2E1 expression during pregnancy, potentially because of interspecies differences in PL physiology. Taken together, these results indicate that PL induces CYP2E1 expression via PI3-kinase pathway in human hepatocytes.
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Affiliation(s)
- Jin Kyung Lee
- Department of Pharmacy Practice, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois (J.K.L., H.J.C., L.F., J.F., H.J.); College of Pharmacy, Gyeongsang National University, Jinju, South Korea (H.J.C.); Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (F.J.G.); and Department of Biopharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois (H.J.)
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81
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Zhao S, Fu J, Liu F, Rastogi R, Zhang J, Zhao Y. Small interfering RNA directed against CTMP reduces acute traumatic brain injury in a mouse model by activating Akt. Neurol Res 2014; 36:483-90. [PMID: 24670215 DOI: 10.1179/1743132814y.0000000353] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
OBJECTIVE Protein kinase B (PKB/Akt), which is phosphorylated and activated by upstream activators, exerts critical neuroprotective effects by phosphorylating downstream targets after traumatic brain injury (TBI). Studies on the regulation of Akt will be crucial for our understanding of neuronal survival. The goal of this study is to investigate the effects of carboxyl-terminal modulator protein (CTMP) on phosphorylation of Akt and neurological function in a mouse model of TBI. METHODS Traumatic brain injury in mice was performed by a controlled cortical impact device. The expression of Akt, phospho-Akt, and CTMP was examined in the injured cortices by immunohistochemistry and Western blot analysis. To determine the effects of CTMP, small interfering RNAs (siRNAs) directed against CTMP were injected in mice with TBI, and the expression of phosphorylated Akt and neurological function were evaluated. RESULTS Phospho-Akt significantly increased at 4 hours post-TBI in the nucleus (P < 0.01) and remained at high levels until 72 hours after TBI, as shown by Western blot analysis. In the cytosol, the expression of phospho-Akt reached its peak at 4 hours post-TBI, but decreased markedly at 24 hours and maintained below pre-TBI levels until 72 hours post-TBI. Interestingly, the expression of CTMP significantly increased 4 hours after TBI (P < 0.01) and sustained those levels until 72 hours without dramatic changes. Treatment with CTMP siRNA effectively augmented the phosphorylation of Akt and significantly improved the neurological functional recovery up to 28 days post-TBI. CONCLUSION We conclude that Akt is phosphorylated and translocated to nucleus after TBI to exert neuroprotective effects. However, CTMP is simultaneously triggered to inhibit the phosphorylation of Akt. Inhibition of CTMP by siRNA improves the recovery of neurological functions after TBI.
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82
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Agarwal E, Chaudhuri A, Leiphrakpam PD, Haferbier KL, Brattain MG, Chowdhury S. Akt inhibitor MK-2206 promotes anti-tumor activity and cell death by modulation of AIF and Ezrin in colorectal cancer. BMC Cancer 2014; 14:145. [PMID: 24581231 PMCID: PMC3941258 DOI: 10.1186/1471-2407-14-145] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 02/20/2014] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND There is extensive evidence for the role of aberrant cell survival signaling mechanisms in cancer progression and metastasis. Akt is a major component of cell survival-signaling mechanisms in several types of cancer. It has been shown that activated Akt stabilizes XIAP by S87 phosphorylation leading to survivin/XIAP complex formation, caspase inhibition and cytoprotection of cancer cells. We have reported that TGFβ/PKA/PP2A-mediated tumor suppressor signaling regulates Akt phosphorylation in association with the dissociation of survivin/XIAP complexes leading to inhibition of stress-dependent induction of cell survival. METHODS IGF1R-dependent colon cancer cells (GEO and CBS) were used for the study. Effects on cell proliferation and cell death were determined in the presence of MK-2206. Xenograft studies were performed to determine the effect of MK-2206 on tumor volume. The effect on various cell death markers such as XIAP, survivin, AIF, Ezrin, pEzrin was determined by western blot analysis. Graph pad 5.0 was used for statistical analysis. P < 0.05 was considered significant. RESULTS We characterized the mechanisms by which a novel Akt kinase inhibitor MK-2206 induced cell death in IGF1R-dependent colorectal cancer (CRC) cells with upregulated PI3K/Akt signaling in response to IGF1R activation. MK-2206 treatment generated a significant reduction in tumor growth in vivo and promoted cell death through two mechanisms. This is the first report demonstrating that Akt inactivation by MK-2206 leads to induction of and mitochondria-to-nuclear localization of the Apoptosis Inducing Factor (AIF), which is involved in caspase-independent cell death. We also observed that exposure to MK-2206 dephosphorylated Ezrin at the T567 site leading to the disruption of Akt-pEzrin-XIAP cell survival signaling. Ezrin phosphorylation at this site has been associated with malignant progression in solid tumors. CONCLUSION The identification of these 2 novel mechanisms leading to induction of cell death indicates MK-2206 might be a potential clinical candidate for therapeutic targeting of the subset of IGF1R-dependent cancers in CRC.
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Affiliation(s)
| | | | | | | | - Michael G Brattain
- Eppley Cancer Center, University of Nebraska Medical Center, 985950 Nebraska Medical Center, Omaha, Nebraska 68198-5950, USA.
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83
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Gálvez-Peralta M, Flatten KS, Loegering DA, Peterson KL, Schneider PA, Erlichman C, Kaufmann SH. Context-dependent antagonism between Akt inhibitors and topoisomerase poisons. Mol Pharmacol 2014; 85:723-34. [PMID: 24569089 DOI: 10.1124/mol.113.088674] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Signaling through the phosphatidylinositol-3 kinase (PI3K)/Akt pathway, which is aberrantly activated in >50% of carcinomas, inhibits apoptosis and contributes to drug resistance. Accordingly, several Akt inhibitors are currently undergoing preclinical or early clinical testing. To examine the effect of Akt inhibition on the activity of multiple widely used classes of antineoplastic agents, human cancer cell lines were treated with the Akt inhibitor A-443654 [(2S)-1-(1H-indol-3-yl)-3-[5-(3-methyl-2H-indazol-5-yl)pyridin-3-yl]oxypropan-2-amine; ATP-competitive] or MK-2206 (8-[4-(1-aminocyclobutyl)phenyl]-9-phenyl-2H-[1,2,4]triazolo[3,4-f][1,6]naphthyridin-3-one;dihydrochloride; allosteric inhibitor) or with small interfering RNA (siRNA) targeting phosphoinositide-dependent kinase 1 (PDK1) along with cisplatin, melphalan, camptothecin, or etoposide and assayed for colony formation. Surprisingly different results were observed when Akt inhibitors were combined with different drugs. Synergistic effects were observed in multiple cell lines independent of PI3K pathway status when A-443654 or MK-2206 was combined with the DNA cross-linking agents cisplatin or melphalan. In contrast, effects of the Akt inhibitors in combination with camptothecin or etoposide were more complicated. In HCT116 and DLD1 cells, which harbor activating PI3KCA mutations, A-443654 over a broad concentration range enhanced the effects of camptothecin or etoposide. In contrast, in cell lines lacking activating PI3KCA mutations, partial inhibition of Akt signaling synergized with camptothecin or etoposide, but higher A-443654 or MK-2206 concentrations (>80% inhibition of Akt signaling) or PDK1 siRNA antagonized the topoisomerase poisons by diminishing DNA synthesis, a process that contributes to effective DNA damage and killing by these agents. These results indicate that the effects of combining inhibitors of the PI3K/Akt pathway with certain classes of chemotherapeutic agents might be more complicated than previously recognized.
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Affiliation(s)
- Marina Gálvez-Peralta
- Divisions of Oncology Research (M.G.-P., K.S.F., D.A.L., K.L.P., P.A.S., S.H.K.) and Medical Oncology (C.E.), Department of Oncology and Department of Molecular Pharmacology & Experimental Therapeutics (S.H.K.), Mayo Clinic College of Medicine, Rochester, Minnesota
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84
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Everts B, Amiel E, Huang SCC, Smith AM, Chang CH, Lam WY, Redmann V, Freitas TC, Blagih J, van der Windt GJW, Artyomov MN, Jones RG, Pearce EL, Pearce EJ. TLR-driven early glycolytic reprogramming via the kinases TBK1-IKKɛ supports the anabolic demands of dendritic cell activation. Nat Immunol 2014; 15:323-32. [PMID: 24562310 DOI: 10.1038/ni.2833] [Citation(s) in RCA: 757] [Impact Index Per Article: 75.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Accepted: 01/24/2014] [Indexed: 12/14/2022]
Abstract
The ligation of Toll-like receptors (TLRs) leads to rapid activation of dendritic cells (DCs). However, the metabolic requirements that support this process remain poorly defined. We found that DC glycolytic flux increased within minutes of exposure to TLR agonists and that this served an essential role in supporting the de novo synthesis of fatty acids for the expansion of the endoplasmic reticulum and Golgi required for the production and secretion of proteins that are integral to DC activation. Signaling via the kinases TBK1, IKKɛ and Akt was essential for the TLR-induced increase in glycolysis by promoting the association of the glycolytic enzyme HK-II with mitochondria. In summary, we identified the rapid induction of glycolysis as an integral component of TLR signaling that is essential for the anabolic demands of the activation and function of DCs.
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Affiliation(s)
- Bart Everts
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Eyal Amiel
- Department of Medical Laboratory and Radiation Sciences, University of Vermont, Burlington, Vermont, USA
| | - Stanley Ching-Cheng Huang
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Amber M Smith
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Chih-Hao Chang
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Wing Y Lam
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Veronika Redmann
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
| | | | | | - Gerritje J W van der Windt
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Maxim N Artyomov
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Russell G Jones
- Department of Physiology, McGill University, Montreal, Quebec, Canada
| | - Erika L Pearce
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Edward J Pearce
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
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Phosphorylated AKT inhibits the apoptosis induced by DRAM-mediated mitophagy in hepatocellular carcinoma by preventing the translocation of DRAM to mitochondria. Cell Death Dis 2014; 5:e1078. [PMID: 24556693 PMCID: PMC3944266 DOI: 10.1038/cddis.2014.51] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 12/14/2013] [Accepted: 12/23/2013] [Indexed: 12/15/2022]
Abstract
Increasing autophagy is beneficial for curing hepatocellular carcinoma (HCC). Damage-regulated autophagy modulator (DRAM) was recently reported to induce apoptosis by mediating autophagy. However, the effects of DRAM-mediated autophagy on apoptosis in HCC cells remain unclear. In this study, normal hepatocytes (7702) and HCC cell lines (HepG2, Hep3B and Huh7) were starved for 48 h. Starvation induced apoptosis and autophagy in all cell lines. We determined that starvation also induced DRAM expression and DRAM-mediated autophagy in both normal hepatocytes and HCC cells. However, DRAM-mediated autophagy was involved in apoptosis in normal hepatocytes but not in HCC cells, suggesting that DRAM-mediated autophagy fails to induce apoptosis in hepatoma in response to starvation. Immunoblot and immunofluorescence assays demonstrated that DRAM translocated to mitochondria and induced mitophagy, which led to apoptosis in 7702 cells. In HCC cells, starvation also activated the phosphatidylinositol 3-kinase (PI3K)/AKT pathway, which blocks the translocation of DRAM to mitochondria through the binding of p-AKT to DRAM in the cytoplasm. Inactivation of the PI3K/AKT pathway rescued DRAM translocation to mitochondria; subsequently, mitochondrial DRAM induced apoptosis in HCC cells by mediating mitophagy. Our findings open new avenues for the investigation of the mechanisms of DRAM-mediated autophagy and suggest that promoting DRAM-mediated autophagy together with PI3K/AKT inhibition might be more effective for autophagy-based therapy in hepatoma.
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86
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Gross C, Bassell GJ. Neuron-specific regulation of class I PI3K catalytic subunits and their dysfunction in brain disorders. Front Mol Neurosci 2014; 7:12. [PMID: 24592210 PMCID: PMC3923137 DOI: 10.3389/fnmol.2014.00012] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 01/28/2014] [Indexed: 11/13/2022] Open
Abstract
The phosphoinositide 3-kinase (PI3K) complex plays important roles in virtually all cells of the body. The enzymatic activity of PI3K to phosphorylate phosphoinositides in the membrane is mediated by a group of catalytic and regulatory subunits. Among those, the class I catalytic subunits, p110α, p110β, p110γ, and p110δ, have recently drawn attention in the neuroscience field due to their specific dysregulation in diverse brain disorders. While in non-neuronal cells these catalytic subunits may have partially redundant functions, there is increasing evidence that in neurons their roles are more specialized, and confined to distinct receptor-dependent pathways. This review will summarize the emerging role of class I PI3K catalytic subunits in neurotransmitter-regulated neuronal signaling, and their dysfunction in a variety of neurological diseases, including fragile X syndrome, schizophrenia, and epilepsy. We will discuss recent literature describing the use of PI3K subunit-selective inhibitors to rescue brain disease-associated phenotypes in in vitro and animal models. These studies give rise to the exciting prospect that these drugs, originally designed for cancer treatment, may be repurposed as therapeutic drugs for brain disorders in the future.
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Affiliation(s)
- Christina Gross
- Department of Cell Biology, Emory University School of Medicine Atlanta, GA, USA ; Center for Translational Social Neuroscience, Emory University School of Medicine Atlanta, GA, USA
| | - Gary J Bassell
- Department of Cell Biology, Emory University School of Medicine Atlanta, GA, USA ; Center for Translational Social Neuroscience, Emory University School of Medicine Atlanta, GA, USA ; Department of Neurology, Emory University School of Medicine Atlanta, GA, USA
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87
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Iida M, Brand TM, Campbell DA, Starr MM, Luthar N, Traynor AM, Wheeler DL. Targeting AKT with the allosteric AKT inhibitor MK-2206 in non-small cell lung cancer cells with acquired resistance to cetuximab. Cancer Biol Ther 2014; 14:481-91. [PMID: 23760490 DOI: 10.4161/cbt.24342] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The epidermal growth factor receptor (EGFR) is a central regulator of tumor progression in human cancers. Cetuximab is an anti-EGFR monoclonal antibody that has been approved for use in oncology. Despite clinical success the majority of patients do not respond to cetuximab and those who initially respond frequently acquire resistance. To understand how tumor cells acquire resistance to cetuximab we developed a model of resistance using the non-small cell lung cancer line NCI-H226. We found that cetuximab-resistant (Ctx (R) ) clones manifested strong activation of EGFR, PI3K/AKT and MAPK. To investigate the role of AKT signaling in cetuximab resistance we analyzed the activation of the AKT pathway effector molecules using a human AKT phospho-antibody array. Strong activation was observed in Ctx (R) clones for several key AKT substrates including c-jun, GSK3β, eIF4E, rpS6, IKKα, IRS-1 and Raf1. Inhibition of AKT signaling by siAKT1/2 or by the allosteric AKT inhibitor MK-2206 resulted in robust inhibition of cell proliferation in all Ctx (R) clones. Moreover, the combinational treatment of cetuximab and MK-2206 resulted in further decreases in proliferation than either drug alone. This combinatorial treatment resulted in decreased activity of both AKT and MAPK thus highlighting the importance of simultaneous pathway inhibition to maximally affect the growth of Ctx (R) cells. Collectively, our findings demonstrate that AKT activation is an important pathway in acquired resistance to cetuximab and suggests that combinatorial therapy directed at both the AKT and EGFR/MAPK pathways may be beneficial in this setting.
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Affiliation(s)
- Mari Iida
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, Wisconsin Institute for Medical Research, Madison, WI, USA
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88
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Villani V, Milanesi A, Sedrakyan S, Da Sacco S, Angelow S, Conconi MT, Di Liddo R, De Filippo R, Perin L. Amniotic fluid stem cells prevent β-cell injury. Cytotherapy 2013; 16:41-55. [PMID: 24210784 DOI: 10.1016/j.jcyt.2013.08.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 08/19/2013] [Accepted: 08/25/2013] [Indexed: 01/02/2023]
Abstract
BACKGROUND AIMS The contribution of amniotic fluid stem cells (AFSC) to tissue protection and regeneration in models of acute and chronic kidney injuries and lung failure has been shown in recent years. In the present study, we used a chemically induced mouse model of type 1 diabetes to determine whether AFSC could play a role in modulating β-cell injury and restoring β-cell function. METHODS Streptozotocin-induced diabetic mice were given intracardial injection of AFSC; morphological and physiological parameters and gene expression profile for the insulin pathway were evaluated after cell transplantation. RESULTS AFSC injection resulted in protection from β-cell damage and increased β-cell regeneration in a subset of mice as indicated by glucose and insulin levels, increased islet mass and preservation of islet structure. Moreover, β-cell preservation/regeneration correlated with activation of the insulin receptor/Pi3K/Akt signaling pathway and vascular endothelial growth factor-A expression involved in maintaining β-cell mass and function. CONCLUSIONS Our results suggest a therapeutic role for AFSC in preserving and promoting endogenous β-cell functionality and proliferation. The protective role of AFSC is evident when stem cell transplantation is performed before severe hyperglycemia occurs, which suggests the importance of early intervention. The present study demonstrates the possible benefits of the application of a non-genetically engineered stem cell population derived from amniotic fluid for the treatment of type 1 diabetes mellitus and gives new insight on the mechanism by which the beneficial effect is achieved.
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Affiliation(s)
- Valentina Villani
- Department of Urology, Children's Hospital Los Angeles, University of Southern California, Los Angeles, California
| | - Anna Milanesi
- Division of Endocrinology, VA Greater Los Angeles Healthcare System, University of California Los Angeles, Los Angeles, California
| | - Sargis Sedrakyan
- Department of Urology, Children's Hospital Los Angeles, University of Southern California, Los Angeles, California
| | - Stefano Da Sacco
- Department of Urology, Children's Hospital Los Angeles, University of Southern California, Los Angeles, California
| | - Susanne Angelow
- Department of Urology, Children's Hospital Los Angeles, University of Southern California, Los Angeles, California
| | | | - Rosa Di Liddo
- Department of Pharmaceutical Sciences, University of Padua, Padua, Italy
| | - Roger De Filippo
- Department of Urology, Children's Hospital Los Angeles, University of Southern California, Los Angeles, California
| | - Laura Perin
- Department of Urology, Children's Hospital Los Angeles, University of Southern California, Los Angeles, California.
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Srivastava N, Sudan R, Kerr WG. Role of inositol poly-phosphatases and their targets in T cell biology. Front Immunol 2013; 4:288. [PMID: 24069021 PMCID: PMC3779868 DOI: 10.3389/fimmu.2013.00288] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Accepted: 09/03/2013] [Indexed: 11/13/2022] Open
Abstract
T lymphocytes play a critical role in host defense in all anatomical sites including mucosal surfaces. This not only includes the effector arm of the immune system, but also regulation of immune responses in order to prevent autoimmunity. Genetic targeting of PI3K isoforms suggests that generation of PI(3,4,5)P3 by PI3K plays a critical role in promoting effector T cell responses. Consequently, the 5'- and 3'-inositol poly-phosphatases SHIP1, SHIP2, and phosphatase and tensin homolog capable of targeting PI(3,4,5)P3 are potential genetic determinants of T cell effector functions in vivo. In addition, the 5'-inositol poly-phosphatases SHIP1 and 2 can shunt PI(3,4,5)P3 to the rare but potent signaling phosphoinositide species PI(3,4)P2 and thus these SHIP1/2, and the INPP4A/B enzymes that deplete PI(3,4)P2 may have precise roles in T cell biology to amplify or inhibit effectors of PI3K signaling that are selectively recruited to and activated by PI(3,4)P2. Here we summarize recent genetic and chemical evidence that indicates the inositol poly-phosphatases have important roles in both the effector and regulatory functions of the T cell compartment. In addition, we will discuss future genetic studies that might be undertaken to further elaborate the role of these enzymes in T cell biology as well as potential pharmaceutical manipulation of these enzymes for therapeutic purposes in disease settings where T cell function is a key in vivo target.
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Affiliation(s)
- Neetu Srivastava
- Department of Microbiology and Immunology, SUNY Upstate Medical University , Syracuse, NY , USA
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Dual phosphorylation of Btk by Akt/protein kinase b provides docking for 14-3-3ζ, regulates shuttling, and attenuates both tonic and induced signaling in B cells. Mol Cell Biol 2013; 33:3214-26. [PMID: 23754751 DOI: 10.1128/mcb.00247-13] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bruton's tyrosine kinase (Btk) is crucial for B-lymphocyte activation and development. Mutations in the Btk gene cause X-linked agammaglobulinemia (XLA) in humans and X-linked immunodeficiency (Xid) in mice. Using tandem mass spectrometry, 14-3-3ζ was identified as a new binding partner and negative regulator of Btk in both B-cell lines and primary B lymphocytes. The activated serine/threonine kinase Akt/protein kinase B (PKB) phosphorylated Btk on two sites prior to 14-3-3ζ binding. The interaction sites were mapped to phosphoserine pS51 in the pleckstrin homology domain and phosphothreonine pT495 in the kinase domain. The double-alanine, S51A/T495A, replacement mutant failed to bind 14-3-3ζ, while phosphomimetic aspartate substitutions, S51D/T495D, caused enhanced interaction. The phosphatidylinositol 3-kinase (PI3-kinase) inhibitor LY294002 abrogated S51/T495 phosphorylation and binding. A newly characterized 14-3-3 inhibitor, BV02, reduced binding, as did the Btk inhibitor PCI-32765 (ibrutinib). Interestingly, in the presence of BV02, phosphorylation of Btk, phospholipase Cγ2, and NF-κB increased strongly, suggesting that 14-3-3 also regulates B-cell receptor (BCR)-mediated tonic signaling. Furthermore, downregulation of 14-3-3ζ elevated nuclear translocation of Btk. The loss-of-function mutant S51A/T495A showed reduced tyrosine phosphorylation and ubiquitination. Conversely, the gain-of-function mutant S51D/T495D exhibited intense tyrosine phosphorylation, associated with Btk ubiquitination and degradation, likely contributing to the termination of BCR signaling. Collectively, this suggests that Btk could become an important new candidate for the general study of 14-3-3-mediated regulation.
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McNamara CR, Ahuja R, Osafo-Addo AD, Barrows D, Kettenbach A, Skidan I, Teng X, Cuny GD, Gerber S, Degterev A. Akt Regulates TNFα synthesis downstream of RIP1 kinase activation during necroptosis. PLoS One 2013; 8:e56576. [PMID: 23469174 PMCID: PMC3585731 DOI: 10.1371/journal.pone.0056576] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 01/15/2013] [Indexed: 11/29/2022] Open
Abstract
Necroptosis is a regulated form of necrotic cell death that has been implicated in the pathogenesis of various diseases including intestinal inflammation and systemic inflammatory response syndrome (SIRS). In this work, we investigated the signaling mechanisms controlled by the necroptosis mediator receptor interacting protein-1 (RIP1) kinase. We show that Akt kinase activity is critical for necroptosis in L929 cells and plays a key role in TNFα production. During necroptosis, Akt is activated in a RIP1 dependent fashion through its phosphorylation on Thr308. In L929 cells, this activation requires independent signaling inputs from both growth factors and RIP1. Akt controls necroptosis through downstream targeting of mammalian Target of Rapamycin complex 1 (mTORC1). Akt activity, mediated in part through mTORC1, links RIP1 to JNK activation and autocrine production of TNFα. In other cell types, such as mouse lung fibroblasts and macrophages, Akt exhibited control over necroptosis-associated TNFα production without contributing to cell death. Overall, our results provide new insights into the mechanism of necroptosis and the role of Akt kinase in both cell death and inflammatory regulation.
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Affiliation(s)
- Colleen R. McNamara
- Graduate Program in Biochemistry, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, Massachussets, United States of America
| | - Ruchita Ahuja
- Department of Biochemistry, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, Massachussets, United States of America
| | - Awo D. Osafo-Addo
- Department of Biochemistry, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, Massachussets, United States of America
| | - Douglas Barrows
- Department of Biochemistry, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, Massachussets, United States of America
| | - Arminja Kettenbach
- Department of Genetics, Dartmouth Medical School, Lebanon, New Hampshire, United States of America
| | - Igor Skidan
- Department of Biochemistry, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, Massachussets, United States of America
| | - Xin Teng
- Laboratory for Drug Discovery in Neurodegeneration, Harvard NeuroDiscovery Center, Brigham and Women’s Hospital and Harvard Medical School, Cambridge, Massachussets, United States of America
| | - Gregory D. Cuny
- Laboratory for Drug Discovery in Neurodegeneration, Harvard NeuroDiscovery Center, Brigham and Women’s Hospital and Harvard Medical School, Cambridge, Massachussets, United States of America
| | - Scott Gerber
- Department of Genetics, Dartmouth Medical School, Lebanon, New Hampshire, United States of America
| | - Alexei Degterev
- Department of Biochemistry, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, Massachussets, United States of America
- * E-mail:
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92
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Riedel A, Mofolo B, Avota E, Schneider-Schaulies S, Meintjes A, Mulder N, Kneitz S. Accumulation of splice variants and transcripts in response to PI3K inhibition in T cells. PLoS One 2013; 8:e50695. [PMID: 23383294 PMCID: PMC3562341 DOI: 10.1371/journal.pone.0050695] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Accepted: 10/23/2012] [Indexed: 12/17/2022] Open
Abstract
Background Measles virus (MV) causes T cell suppression by interference with phosphatidylinositol-3-kinase (PI3K) activation. We previously found that this interference affected the activity of splice regulatory proteins and a T cell inhibitory protein isoform was produced from an alternatively spliced pre-mRNA. Hypothesis Differentially regulated and alternatively splice variant transcripts accumulating in response to PI3K abrogation in T cells potentially encode proteins involved in T cell silencing. Methods To test this hypothesis at the cellular level, we performed a Human Exon 1.0 ST Array on RNAs isolated from T cells stimulated only or stimulated after PI3K inhibition. We developed a simple algorithm based on a splicing index to detect genes that undergo alternative splicing (AS) or are differentially regulated (RG) upon T cell suppression. Results Applying our algorithm to the data, 9% of the genes were assigned as AS, while only 3% were attributed to RG. Though there are overlaps, AS and RG genes differed with regard to functional regulation, and were found to be enriched in different functional groups. AS genes targeted extracellular matrix (ECM)-receptor interaction and focal adhesion pathways, while RG genes were mainly enriched in cytokine-receptor interaction and Jak-STAT. When combined, AS/RG dependent alterations targeted pathways essential for T cell receptor signaling, cytoskeletal dynamics and cell cycle entry. Conclusions PI3K abrogation interferes with key T cell activation processes through both differential expression and alternative splicing, which together actively contribute to T cell suppression.
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Affiliation(s)
- Alice Riedel
- Institute for Virology and Immunobiology, University of Wuerzburg, Versbacher, Wuerzburg, Germany
| | - Boitumelo Mofolo
- Computational Biology Group, Department of Clinical Laboratory Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Faculty of Health Sciences, Cape Town, South Africa
| | - Elita Avota
- Institute for Virology and Immunobiology, University of Wuerzburg, Versbacher, Wuerzburg, Germany
| | | | - Ayton Meintjes
- Computational Biology Group, Department of Clinical Laboratory Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Faculty of Health Sciences, Cape Town, South Africa
| | - Nicola Mulder
- Computational Biology Group, Department of Clinical Laboratory Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Faculty of Health Sciences, Cape Town, South Africa
| | - Susanne Kneitz
- Department of Physiological Chemistry I, Biocenter, University of Wuerzburg, Wuerzburg, Germany
- * E-mail:
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Ju R, Simons M. Syndecan 4 regulation of PDK1-dependent Akt activation. Cell Signal 2013; 25:101-5. [PMID: 22975683 PMCID: PMC3508137 DOI: 10.1016/j.cellsig.2012.09.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Revised: 09/05/2012] [Accepted: 09/05/2012] [Indexed: 12/17/2022]
Abstract
The phosphatidylinositol 3 kinase (Pi3K)/Akt pathway is a major regulator of cell growth, proliferation, metabolism, survival, and angiogenesis. Despite extensive study, a thorough understanding of the modulation and regulation of this pathway has remained elusive. We have previously demonstrated that syndecan 4 (S4) regulates the intracellular localization of mTORC2, thus altering phosphorylation of Akt at serine473 (Ser473), one of two critical phosphorylation sites essential for the full activation of Akt [1]. Here we report that S4 also regulates the phosphorylation of Akt at threonine308 (Thr308), the second phosphorylation site required for the full Akt activation. A deletion of S4 resulted in lower levels of Thr308 phosphorylation both in vitro and in vivo. Furthermore, a deletion or knockdown of the S4 effector molecule PKCα led to a similar reduction in phosphorylation of Thr308 while overexpression of myristoylated PKCα rescued AktThr308 phosphorylation in endothelial cells lacking S4. Finally, PAK1/2 is also recruited to the rafts by the S4-PKCα complex and is required for AKT activation.
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Affiliation(s)
- Rong Ju
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
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95
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Oliveira-Prado R, Caldas IR, Teixeira-Carvalho A, Andrade MV, Fares RCG, Portugal LM, Gazzinelli A, Corrêa-Oliveira R, Cunha-Melo JR. Cytokine profile, proliferation and phosphorylation of ERK1/2 and Akt in circulating mononuclear cells from individuals during the chronic intestinal phase of Schistosomiasis mansoni infection. BMC Infect Dis 2012; 12:380. [PMID: 23270458 PMCID: PMC3549743 DOI: 10.1186/1471-2334-12-380] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Accepted: 11/19/2012] [Indexed: 12/26/2022] Open
Abstract
Background The immune response to Schistosoma mansoni is characterized by a granulomatous reaction around the parasite eggs that are trapped in the host liver, and this reaction modulates the immune response during the chronic phase of the disease. The typical peripheral blood mononuclear cell (PBMC) response of patients during the chronic intestinal phase of infection is characterized by a decreased response to an S. mansoni soluble egg antigen. To obtain a greater understanding of Schistosoma infections, this study investigated the effects of the soluble egg antigen (SEA) and soluble adult worm antigen (SWAP) of S. mansoni on cellular proliferation, cytokine production, and ERK1/2 and Akt phosphorylation in PBMCs from infected (XTO) and egg-negative (NI) individuals living in the same endemic area. Methods The activation status was evaluated by cell immunophenotypic staining (cytometry). The cell proliferation assay was by CFSE method. Cytokine detection assay (Th1 and Th2) was by Cytometric Bead and Array phosphorylation status was by ELISA. Results The XTO, NI and BD (blood donor) individuals from an area not endemic for schistosomiasis were compared. The CD4+ T lymphocyte proliferation rate was lower in the XTO group, but not the NI group, after SEA stimulation compared to the BD group. The CD8+ T cell proliferation rate was lower in the XTO group in the unstimulated cultures and after both SEA and SWAP stimulation compared to the BD group. Cytokine analysis after either SEA or SWAP stimulation showed a balanced cytokine pattern in the XTO and NI groups. ERK1/2 and Akt phosphorylation were only marginally detected in all groups; however, a decrease in ERK 1/2 phosphorylation was observed in the SWAP-stimulated XTO group compared to both the NI and BD groups. Conclusions The data indicate that SEA-stimulated CD4+ T cells from infected patients have a lower proliferation rate than the same cells from the NI group. Furthermore, we observed that SWAP stimulation influences ERK1/2 phosphorylation in the XTO group.
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Chen B, Liu J, Chang Q, Beezhold K, Lu Y, Chen F. JNK and STAT3 signaling pathways converge on Akt-mediated phosphorylation of EZH2 in bronchial epithelial cells induced by arsenic. Cell Cycle 2012; 12:112-21. [PMID: 23255093 DOI: 10.4161/cc.23030] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The molecular mechanisms by which arsenic (As ( 3+) ) causes human cancers remain to be fully elucidated. Enhancer of zeste homolog 2 (EZH2) is the catalytic subunit of polycomb-repressive complexes 2 (PRC2) that promotes trimethylation of lysine 27 of histone H3, leading to altered expression of tumor suppressors or oncogenes. In the present study, we determined the effect of As ( 3+) on EZH2 phosphorylation and the signaling pathways important for As ( 3+) -induced EZH2 phosphorylation in human bronchial epithelial cell line BEAS-2B. The involvement of kinases in As ( 3+) -induced EZH2 phosphorylation was validated by siRNA-based gene silencing. The data showed that As ( 3+) can induce phosphorylation of EZH2 at serine 21 in human bronchial epithelial cells and that the phosphorylation of EZH2 requires an As ( 3+) -activated signaling cascade from JNK and STAT3 to Akt. Transfection of the cells with siRNA specific for JNK1 revealed that JNK silencing reduced serine727 phosphorylation of STAT3, Akt activation and EZH2 phosphorylation, suggesting that JNK is the upstream kinase involved in As ( 3+) -induced EZH2 phosphorylation. Because As ( 3+) is capable of inducing miRNA-21 (miR-21), a STAT3-regulated miRNA that represses protein translation of PTEN or Spry2, we also tested the role of STAT3 and miR-21 in As ( 3+) -induced EZH2 phosphorylation. Ectopic overexpression of miR-21 promoted Akt activation and phosphorylation of EZH2, whereas inhibiting miR-21 by transfecting the cells with anti-miR-21 inhibited Akt activation and EZH2 phosphorylation. Taken together, these results demonstrate a contribution of the JNK, STAT3 and Akt signaling axis to As ( 3+) -induced EZH2 phosphorylation. Importantly, these findings may reveal new molecular mechanisms underlying As ( 3+) -induced carcinogenesis.
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Affiliation(s)
- Bailing Chen
- Department of Pharmaceutical Sciences, Wayne State University, Detroit, MI, USA
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Misra UK, Pizzo SV. Receptor-recognized α₂-macroglobulin binds to cell surface-associated GRP78 and activates mTORC1 and mTORC2 signaling in prostate cancer cells. PLoS One 2012; 7:e51735. [PMID: 23272152 PMCID: PMC3522726 DOI: 10.1371/journal.pone.0051735] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 11/05/2012] [Indexed: 02/02/2023] Open
Abstract
OBJECTIVE Tetrameric α(2)-macroglobulin (α(2)M), a plasma panproteinase inhibitor, is activated upon interaction with a proteinase, and undergoes a major conformational change exposing a receptor recognition site in each of its subunits. Activated α(2)M (α(2)M*) binds to cancer cell surface GRP78 and triggers proliferative and antiapoptotic signaling. We have studied the role of α(2)M* in the regulation of mTORC1 and TORC2 signaling in the growth of human prostate cancer cells. METHODS Employing immunoprecipitation techniques and Western blotting as well as kinase assays, activation of the mTORC1 and mTORC2 complexes, as well as down stream targets were studied. RNAi was also employed to silence expression of Raptor, Rictor, or GRP78 in parallel studies. RESULTS Stimulation of cells with α(2)M* promotes phosphorylation of mTOR, TSC2, S6-Kinase, 4EBP, Akt(T308), and Akt(S473) in a concentration and time-dependent manner. Rheb, Raptor, and Rictor also increased. α(2)M* treatment of cells elevated mTORC1 kinase activity as determined by kinase assays of mTOR or Raptor immunoprecipitates. mTORC1 activity was sensitive to LY294002 and rapamycin or transfection of cells with GRP78 dsRNA. Down regulation of Raptor expression by RNAi significantly reduced α(2)M*-induced S6-Kinase phosphorylation at T389 and kinase activity in Raptor immunoprecipitates. α(2)M*-treated cells demonstrate about a twofold increase in mTORC2 kinase activity as determined by kinase assay of Akt(S473) phosphorylation and levels of p-Akt(S473) in mTOR and Rictor immunoprecipitates. mTORC2 activity was sensitive to LY294002 and transfection of cells with GRP78 dsRNA, but insensitive to rapamycin. Down regulation of Rictor expression by RNAi significantly reduces α(2)M*-induced phosphorylation of Akt(S473) phosphorylation in Rictor immunoprecipitates. CONCLUSION Binding of α(2)M* to prostate cancer cell surface GRP78 upregulates mTORC1 and mTORC2 activation and promotes protein synthesis in the prostate cancer cells.
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Affiliation(s)
- Uma K. Misra
- Department of Pathology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Salvatore V. Pizzo
- Department of Pathology, Duke University Medical Center, Durham, North Carolina, United States of America
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Yang Y, Li XJ, Chen Z, Zhu XX, Wang J, Zhang LB, Qiang L, Ma YJ, Li ZY, Guo QL, You QD. Wogonin induced calreticulin/annexin A1 exposure dictates the immunogenicity of cancer cells in a PERK/AKT dependent manner. PLoS One 2012; 7:e50811. [PMID: 23251389 PMCID: PMC3520942 DOI: 10.1371/journal.pone.0050811] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Accepted: 10/29/2012] [Indexed: 12/22/2022] Open
Abstract
In response to ionizing irradiation and certain chemotherapeutic agents, dying tumor cells elicit a potent anticancer immune response. However, the potential effect of wogonin (5,7-dihydroxy-8-methoxyflavone) on cancer immunogenicity has not been studied. Here we demonstrated for the first time that wogonin elicits a potent antitumor immunity effect by inducing the translocation of calreticulin (CRT) and Annexin A1 to cell plasma membrane as well as the release of high-mobility group protein 1 (HMGB1) and ATP. Signal pathways involved in this process were studied. We found that wogonin-induced reactive oxygen species (ROS) production causes an endoplasmic reticulum (ER) stress response, including the phosphorylation of PERK (PKR-like endoplasmic reticulum kinase)/PKR (protein kinase R) and eIF2α (eukaryotic initiation factor 2α), which served as upstream signal for the activation of phosphoinositide 3-kinase (PI3K)/AKT, inducing calreticulin (CRT)/Annexin A1 cell membrane translocation. P22/CHP, a Ca2+-binding protein, was associated with CRT and was required for CRT translocation to cell membrane. The releases of HMGB1 and ATP from wogonin treated MFC cells, alone or together with other possible factors, activated dendritic cells and induced cytokine releases. In vivo study confirmed that immunization with wogonin-pretreated tumor cells vaccination significantly inhibited homoplastic grafted gastric tumor growth in mice and a possible inflammatory response was involved. In conclusion, the activation of PI3K pathway elicited by ER stress induced CRT/Annexin A1 translocation (“eat me” signal) and HMGB1 release, mediating wogonin-induced immunity of tumor cell vaccine. This indicated that wogonin is a novel effective candidate of immunotherapy against gastric tumor.
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Affiliation(s)
- Yong Yang
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, People's Republic of China
| | - Xian-Jing Li
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, People's Republic of China
| | - Zhen Chen
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, People's Republic of China
| | - Xuan-Xuan Zhu
- Department of Pharmacology, Jiangsu Provincial Hospital of Traditional Chinese Medicine, Nanjing, People's Republic of China
| | - Jing Wang
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, People's Republic of China
| | - Lin-bo Zhang
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, People's Republic of China
| | - Lei Qiang
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, People's Republic of China
| | - Yan-jun Ma
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, People's Republic of China
| | - Zhi-yu Li
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, People's Republic of China
| | - Qing-Long Guo
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, People's Republic of China
- * E-mail: (Q-LG); (Q-DY)
| | - Qi-Dong You
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, People's Republic of China
- * E-mail: (Q-LG); (Q-DY)
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Abstract
Natural killer (NK) cells have important functions in cancer immunosurveillance, BM allograft rejection, fighting infections, tissue homeostasis, and reproduction. NK cell-based therapies are promising treatments for blood cancers. Overcoming their currently limited efficacy requires a better understanding of the molecular mechanisms controlling NK cell development and dampening their effector functions. NK cells recognize the loss of self-antigens or up-regulation of stress-induced ligands on pathogen-infected or tumor cells through invariant NK cell receptors (NKRs), and then kill such stressed cells. Two second-messenger pathways downstream of NKRs are required for NK cell maturation and effector responses: PIP(3) generation by PI3K and generation of diacylglycerol and IP(3) by phospholipase-Cγ (PLCγ). In the present study, we identify a novel role for the phosphorylated IP(3) metabolite inositol (1,3,4,5)tetrakisphosphate (IP(4)) in NK cells. IP(4) promotes NK cell terminal differentiation and acquisition of a mature NKR repertoire. However, in mature NK cells, IP(4) limits NKR-induced IFNγ secretion, granule exocytosis, and target-cell killing, in part by inhibiting the PIP(3) effector-kinase Akt. This identifies IP(4) as an important novel regulator of NK cell development and function and expands our understanding of the therapeutically important mechanisms dampening NK cell responses. Our results further suggest that PI3K regulation by soluble IP(4) is a broadly important signaling paradigm.
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Disruption of PH-kinase domain interactions leads to oncogenic activation of AKT in human cancers. Proc Natl Acad Sci U S A 2012; 109:19368-73. [PMID: 23134728 DOI: 10.1073/pnas.1204384109] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The protein kinase v-akt murine thymoma viral oncogene homolog (AKT), a key regulator of cell survival and proliferation, is frequently hyperactivated in human cancers. Intramolecular pleckstrin homology (PH) domain-kinase domain (KD) interactions are important in maintaining AKT in an inactive state. AKT activation proceeds after a conformational change that dislodges the PH from the KD. To understand these autoinhibitory interactions, we generated mutations at the PH-KD interface and found that most of them lead to constitutive activation of AKT. Such mutations are likely another mechanism by which activation may occur in human cancers and other diseases. In support of this likelihood, we found somatic mutations in AKT1 at the PH-KD interface that have not been previously described in human cancers. Furthermore, we show that the AKT1 somatic mutants are constitutively active, leading to oncogenic signaling. Additionally, our studies show that the AKT1 mutants are not effectively inhibited by allosteric AKT inhibitors, consistent with the requirement for an intact PH-KD interface for allosteric inhibition. These results have important implications for therapeutic intervention in patients with AKT mutations at the PH-KD interface.
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