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Zhang XH, Hsiang J, Rosen ST. Flavopiridol (Alvocidib), a Cyclin-dependent Kinases (CDKs) Inhibitor, Found Synergy Effects with Niclosamide in Cutaneous T-cell Lymphoma. JOURNAL OF CLINICAL HAEMATOLOGY 2021; 2:48-61. [PMID: 34223559 PMCID: PMC8248901 DOI: 10.33696/haematology.2.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Flavopiridol (FVP; Alvocidib), a CDKs inhibitor, is currently undergoing clinical trials for treatment of leukemia and other blood cancers. Our studies demonstrated that FVP also inhibited p38 kinases activities with IC50 (μM) for p38α: 1.34; p38 β: 1.82; p38γ: 0.65, and p38δ: 0.45. FVP showed potent cytotoxicity in cutaneous T-cell lymphoma (CTCL) Hut78 cells, with IC50 <100 nM. NMR analysis revealed that FVP bound to p38γ in the ATP binding pocket, causing allosteric perturbation from sites surrounding the ATP binding pocket. Kinomic profiling with the PamGene platform in both cell-based and cell-free analysis further revealed dosage of FVP significantly affects downstream pathways in treated CTCL cells, which suggested a need for development of synergistic drugs with FVP to prevent its clinically adverse effects. It led us discover niclosamide as a synergistic drug of FVP for our future in vivo study.
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Affiliation(s)
- Xu Hannah Zhang
- Department of Hematology and Hematopoietic Cell Transplantation, City of Hope, Beckman Research Institute, National Medical Center, Duarte, CA 91010, USA
| | - Jack Hsiang
- Department of Hematology and Hematopoietic Cell Transplantation, City of Hope, Beckman Research Institute, National Medical Center, Duarte, CA 91010, USA
| | - Steven T Rosen
- Department of Hematology and Hematopoietic Cell Transplantation, City of Hope, Beckman Research Institute, National Medical Center, Duarte, CA 91010, USA
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Kratimenos P, Goldstein EZ, Koutroulis I, Knoblach S, Jablonska B, Banerjee P, Malaeb SN, Bhattacharya S, Almira-Suarez MI, Gallo V, Delivoria-Papadopoulos M. Epidermal Growth Factor Receptor Inhibition Reverses Cellular and Transcriptomic Alterations Induced by Hypoxia in the Neonatal Piglet Brain. iScience 2020; 23:101766. [PMID: 33294779 PMCID: PMC7683340 DOI: 10.1016/j.isci.2020.101766] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 10/12/2020] [Accepted: 10/30/2020] [Indexed: 02/04/2023] Open
Abstract
Acute hypoxia (HX) causes extensive cellular damage in the developing human cerebral cortex. We found increased expression of activated-EGFR in affected cortical areas of neonates with HX and investigated its functional role in the piglet, which displays a highly evolved, gyrencephalic brain, with a human-like maturation pattern. In the piglet, HX-induced activation of EGFR and Ca2+/calmodulin kinase IV (CaMKIV) caused cell death and pathological alterations in neurons and glia. EGFR blockade inhibited CaMKIV activation, attenuated neuronal loss, increased oligodendrocyte proliferation, and reversed HX-induced astrogliosis. We performed for the first time high-throughput transcriptomic analysis of the piglet cortex to define molecular responses to HX and to uncover genes specifically involved in EGFR signaling in piglet and human brain injury. Our results indicate that specific molecular responses modulated by EGFR may be targeted as a therapeutic strategy for HX injury in the neonatal brain.
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Affiliation(s)
- Panagiotis Kratimenos
- Center for Neuroscience Research, Children's National Research Institute, Children's National Hospital, George Washington University School of Medicine and Health Sciences, 111 Michigan Avenue, NW, Washington, DC 20010 P 202-476-5922, USA
- Department of Pediatrics, Division of Neonatology, Children's National Hospital and George Washington University School of Medicine and Health Sciences, 111 Michigan Avenue, NW, Washington, DC 20010 P 202-602-4889, USA
- Corresponding author
| | - Evan Z. Goldstein
- Center for Neuroscience Research, Children's National Research Institute, Children's National Hospital, George Washington University School of Medicine and Health Sciences, 111 Michigan Avenue, NW, Washington, DC 20010 P 202-476-5922, USA
| | - Ioannis Koutroulis
- Department of Pediatrics, Division of Emergency Medicine, Children's National Hospital and George Washington University School of Medicine and Health Sciences, Washington, DC, USA
- Research Center for Genetic Medicine, Children's National Research Institute, Washington, DC, USA
- Department of Genomics and Precision Medicine, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Susan Knoblach
- Research Center for Genetic Medicine, Children's National Research Institute, Washington, DC, USA
- Department of Genomics and Precision Medicine, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Beata Jablonska
- Center for Neuroscience Research, Children's National Research Institute, Children's National Hospital, George Washington University School of Medicine and Health Sciences, 111 Michigan Avenue, NW, Washington, DC 20010 P 202-476-5922, USA
| | - Payal Banerjee
- Research Center for Genetic Medicine, Children's National Research Institute, Washington, DC, USA
| | - Shadi N. Malaeb
- Department of Pediatrics, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Surajit Bhattacharya
- Research Center for Genetic Medicine, Children's National Research Institute, Washington, DC, USA
| | - M. Isabel Almira-Suarez
- Department of Pathology, Children's National Hospital and George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Vittorio Gallo
- Center for Neuroscience Research, Children's National Research Institute, Children's National Hospital, George Washington University School of Medicine and Health Sciences, 111 Michigan Avenue, NW, Washington, DC 20010 P 202-476-5922, USA
- Corresponding author
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Farina AR, Cappabianca L, Sebastiano M, Zelli V, Guadagni S, Mackay AR. Hypoxia-induced alternative splicing: the 11th Hallmark of Cancer. J Exp Clin Cancer Res 2020; 39:110. [PMID: 32536347 PMCID: PMC7294618 DOI: 10.1186/s13046-020-01616-9] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 06/03/2020] [Indexed: 12/16/2022] Open
Abstract
Hypoxia-induced alternative splicing is a potent driving force in tumour pathogenesis and progression. In this review, we update currents concepts of hypoxia-induced alternative splicing and how it influences tumour biology. Following brief descriptions of tumour-associated hypoxia and the pre-mRNA splicing process, we review the many ways hypoxia regulates alternative splicing and how hypoxia-induced alternative splicing impacts each individual hallmark of cancer. Hypoxia-induced alternative splicing integrates chemical and cellular tumour microenvironments, underpins continuous adaptation of the tumour cellular microenvironment responsible for metastatic progression and plays clear roles in oncogene activation and autonomous tumour growth, tumor suppressor inactivation, tumour cell immortalization, angiogenesis, tumour cell evasion of programmed cell death and the anti-tumour immune response, a tumour-promoting inflammatory response, adaptive metabolic re-programming, epithelial to mesenchymal transition, invasion and genetic instability, all of which combine to promote metastatic disease. The impressive number of hypoxia-induced alternative spliced protein isoforms that characterize tumour progression, classifies hypoxia-induced alternative splicing as the 11th hallmark of cancer, and offers a fertile source of potential diagnostic/prognostic markers and therapeutic targets.
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Affiliation(s)
- Antonietta Rosella Farina
- Department of Applied Clinical and Biotechnological Sciences, University of L’Aquila, 67100 L’Aquila, Italy
| | - Lucia Cappabianca
- Department of Applied Clinical and Biotechnological Sciences, University of L’Aquila, 67100 L’Aquila, Italy
| | - Michela Sebastiano
- Department of Applied Clinical and Biotechnological Sciences, University of L’Aquila, 67100 L’Aquila, Italy
| | - Veronica Zelli
- Department of Applied Clinical and Biotechnological Sciences, University of L’Aquila, 67100 L’Aquila, Italy
| | - Stefano Guadagni
- Department of Applied Clinical and Biotechnological Sciences, University of L’Aquila, 67100 L’Aquila, Italy
| | - Andrew Reay Mackay
- Department of Applied Clinical and Biotechnological Sciences, University of L’Aquila, 67100 L’Aquila, Italy
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4
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The multifunctional role of phospho-calmodulin in pathophysiological processes. Biochem J 2018; 475:4011-4023. [PMID: 30578290 PMCID: PMC6305829 DOI: 10.1042/bcj20180755] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 11/23/2018] [Accepted: 11/30/2018] [Indexed: 02/06/2023]
Abstract
Calmodulin (CaM) is a versatile Ca2+-sensor/transducer protein that modulates hundreds of enzymes, channels, transport systems, transcription factors, adaptors and other structural proteins, controlling in this manner multiple cellular functions. In addition to its capacity to regulate target proteins in a Ca2+-dependent and Ca2+-independent manner, the posttranslational phosphorylation of CaM by diverse Ser/Thr- and Tyr-protein kinases has been recognized as an important additional manner to regulate this protein by fine-tuning its functionality. In this review, we shall cover developments done in recent years in which phospho-CaM has been implicated in signalling pathways that are relevant for the onset and progression of diverse pathophysiological processes. These include diverse systems playing a major role in carcinogenesis and tumour development, prion-induced encephalopathies and brain hypoxia, melatonin-regulated neuroendocrine disorders, hypertension, and heavy metal-induced cell toxicity.
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5
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Kratimenos P, Koutroulis I, Agarwal B, Theocharis S, Delivoria-Papadopoulos M. Effect of Src Kinase inhibition on Cytochrome c, Smac/DIABLO and Apoptosis Inducing Factor (AIF) Following Cerebral Hypoxia-Ischemia in Newborn Piglets. Sci Rep 2017; 7:16664. [PMID: 29192254 PMCID: PMC5709433 DOI: 10.1038/s41598-017-16983-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 11/21/2017] [Indexed: 12/04/2022] Open
Abstract
We have previously shown that cerebral Hypoxia-ischemia (HI) results in activation of Src kinase in the newborn piglet brain. We investigated the regulatory mechanism by which the pre-apoptotic proteins translocate from mitochondria to the cytosol during HI through the Src kinase. Newborn piglets were divided into 3 groups (n = 5/group): normoxic (Nx), HI and HI pre-treated with Src kinase inhibitor PP2 (PP2 + HI). Brain tissue HI was verified by neuropathological analysis and by Adenosine Triphosphate (ATP) and Phosphocreatine (PCr) levels. We used western blots, immunohistochemistry, H&E and biochemical enzyme assays to determine the role of Src kinase on mitochondrial membrane apoptotic protein trafficking. HI resulted in decreased ATP and PCr levels, neuropathological changes and increased levels of cytochrome c, Smac/DIABLO and AIF in the cytosol while their levels were decreased in mitochondria compared to Nx. PP2 decreased the cytosolic levels of pre-apoptotic proteins, attenuated the neuropathological changes and apoptosis and decreased the HI-induced increased activity of caspase-3. Our data suggest that Src kinase may represent a potential target that could interrupt the enzymatic activation of the caspase dependent cell death pathway.
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Affiliation(s)
- Panagiotis Kratimenos
- Department of Pediatrics, Division of Neonatology, Children's National Medical Center, The George Washington University, School of Medicine and Health Sciences, Washington, DC, USA. .,Department of Pediatrics, Drexel University College of Medicine, Philadelphia, PA, USA.
| | - Ioannis Koutroulis
- Department of Pediatrics, Division of Emergency Medicine, Children's National Medical Center, The George Washington University, School of Medicine and Health Sciences, Washington, DC, USA
| | - Beamon Agarwal
- Department of Hematopathology, Montefiore Medical Center, Bronx, NY, USA
| | - Stamatios Theocharis
- First Department of Pathology, National and Kapodistrian University of Athens, School of Medicine, Athens, Greece
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6
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Zhou J, Du T, Li B, Rong Y, Verkhratsky A, Peng L. Crosstalk Between MAPK/ERK and PI3K/AKT Signal Pathways During Brain Ischemia/Reperfusion. ASN Neuro 2015; 7:7/5/1759091415602463. [PMID: 26442853 PMCID: PMC4601130 DOI: 10.1177/1759091415602463] [Citation(s) in RCA: 122] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The epidermal growth factor receptor (EGFR) is linked to the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) and Raf/mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK1/2) signaling pathways. During brain ischemia/reperfusion, EGFR could be transactivated, which stimulates these intracellular signaling cascades that either protect cells or potentiate cell injury. In the present study, we investigated the activation of EGFR, PI3K/AKT, and Raf/MAPK/ERK1/2 during ischemia or reperfusion of the brain using the middle cerebral artery occlusion model. We found that EGFR was phosphorylated and transactivated during both ischemia and reperfusion periods. During ischemia, the activity of PI3K/AKT pathway was significantly increased, as judged from the strong phosphorylation of AKT; this activation was suppressed by the inhibitors of EGFR and Zn-dependent metalloproteinase. Ischemia, however, did not induce ERK1/2 phosphorylation, which was dependent on reperfusion. Coimmunoprecipitation of Son of sevenless 1 (SOS1) with EGFR showed increased association between the receptor and SOS1 in ischemia, indicating the inhibitory node downstream of SOS1. The inhibitory phosphorylation site of Raf-1 at Ser259, but not its stimulatory phosphorylation site at Ser338, was phosphorylated during ischemia. Furthermore, ischemia prompted the interaction between Raf-1 and AKT, while both the inhibitors of PI3K and AKT not only abolished AKT phosphorylation but also restored ERK1/2 phosphorylation. All these findings suggest that Raf/MAPK/ERK1/2 signal pathway is inhibited by AKT via direct phosphorylation and inhibition at Raf-1 node during ischemia. During reperfusion, we observed a significant increase of ERK1/2 phosphorylation but no change in AKT phosphorylation. Inhibitors of reactive oxygen species and phosphatase and tensin homolog restored AKT phosphorylation but abolished ERK1/2 phosphorylation, suggesting that the reactive oxygen species-dependent increase in phosphatase and tensin homolog activity in reperfusion period relieves ERK1/2 from inhibition of AKT.
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Affiliation(s)
- Jing Zhou
- Laboratory of Metabolic Brain Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, Shenyang, P. R. China
| | - Ting Du
- Laboratory of Metabolic Brain Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, Shenyang, P. R. China
| | - Baoman Li
- Laboratory of Metabolic Brain Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, Shenyang, P. R. China
| | - Yan Rong
- Laboratory of Metabolic Brain Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, Shenyang, P. R. China
| | - Alexei Verkhratsky
- Faculty of Life Science, The University of Manchester, UK Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain University of Nizhny Novgorod, Russia
| | - Liang Peng
- Laboratory of Metabolic Brain Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, Shenyang, P. R. China
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7
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HDAC6 deacetylase activity is required for hypoxia-induced invadopodia formation and cell invasion. PLoS One 2013; 8:e55529. [PMID: 23405166 PMCID: PMC3566011 DOI: 10.1371/journal.pone.0055529] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Accepted: 12/27/2012] [Indexed: 02/06/2023] Open
Abstract
Despite significant progress in the cancer field, tumor cell invasion and metastasis remain a major clinical challenge. Cell invasion across tissue boundaries depends largely on extracellular matrix degradation, which can be initiated by formation of actin-rich cell structures specialized in matrix degradation called invadopodia. Although the hypoxic microenvironment within solid tumors has been increasingly recognized as an important driver of local invasion and metastasis, little is known about how hypoxia influences invadopodia biogenesis. Here, we show that histone deacetylase 6 (HDAC6), a cytoplasmic member of the histone deacetylase family, is a novel modulator of hypoxia-induced invadopodia formation. Hypoxia was found to enhance HDAC6 tubulin deacetylase activity through activation of the EGFR pathway. Activated HDAC6, in turn, triggered Smad3 phosphorylation resulting in nuclear accumulation. Inhibition of HDAC6 activity or knockdown of the protein inhibited both hypoxia-induced Smad3 activation and invadopodia formation. Our data provide evidence that hypoxia influences invadopodia formation in a biphasic manner, which involves the activation of HDAC6 deacetylase activity by EGFR, resulting in enhanced Smad phosphorylation and nuclear accumulation. The identification of HDAC6 as a key participant of hypoxia-induced cell invasion may have important therapeutic implications for the treatment of metastasis in cancer patients.
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Palmer LA, May WJ, deRonde K, Brown-Steinke K, Bates JN, Gaston B, Lewis SJ. Ventilatory responses during and following exposure to a hypoxic challenge in conscious mice deficient or null in S-nitrosoglutathione reductase. Respir Physiol Neurobiol 2012. [PMID: 23183419 DOI: 10.1016/j.resp.2012.11.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Exposure to a hypoxic challenge increases ventilation in wild-type (WT) mice that diminish during the challenge (roll-off) whereas return to room air causes an increase in ventilation (short-term facilitation, STF). Since plasma and tissue levels of ventilatory excitant S-nitrosothiols such as S-nitrosoglutathione (GSNO) increase during hypoxia, this study examined whether (1) the initial increase in ventilation is due to generation of GSNO, (2) roll-off is due to increased activity of the GSNO degrading enzyme, GSNO reductase (GSNOR), and (3) STF is limited by GSNOR activity. Initial ventilatory responses to hypoxic challenge (10% O(2), 90% N(2)) were similar in WT, GSNO+/- and GSNO-/- mice. These responses diminished markedly during hypoxic challenge in WT mice whereas there was minimal roll-off in GSNOR+/- and GSNOR-/- mice. Finally, STF was greater in GSNOR+/- and GSNOR-/- mice than in WT mice (especially females). This study suggests that GSNOR degradation of GSNO is a vital step in the expression of ventilatory roll-off and that GSNOR suppresses STF.
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Affiliation(s)
- Lisa A Palmer
- Pediatric Respiratory Medicine, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
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Lucien F, Brochu-Gaudreau K, Arsenault D, Harper K, Dubois CM. Hypoxia-induced invadopodia formation involves activation of NHE-1 by the p90 ribosomal S6 kinase (p90RSK). PLoS One 2011; 6:e28851. [PMID: 22216126 PMCID: PMC3246449 DOI: 10.1371/journal.pone.0028851] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 11/16/2011] [Indexed: 01/12/2023] Open
Abstract
The hypoxic and acidic microenvironments in tumors are strongly associated with malignant progression and metastasis, and have thus become a central issue in tumor physiology and cancer treatment. Despite this, the molecular links between acidic pH- and hypoxia-mediated cell invasion/metastasis remain mostly unresolved. One of the mechanisms that tumor cells use for tissue invasion is the generation of invadopodia, which are actin-rich invasive plasma membrane protrusions that degrade the extracellular matrix. Here, we show that hypoxia stimulates the formation of invadopodia as well as the invasive ability of cancer cells. Inhibition or shRNA-based depletion of the Na(+)/H(+) exchanger NHE-1, along with intracellular pH monitoring by live-cell imaging, revealed that invadopodia formation is associated with alterations in cellular pH homeostasis, an event that involves activation of the Na(+)/H(+) exchange rate by NHE-1. Further characterization indicates that hypoxia triggered the activation of the p90 ribosomal S6 kinase (p90 RSK), which resulted in invadopodia formation and site-specific phosphorylation and activation of NHE-1. This study reveals an unsuspected role of p90RSK in tumor cell invasion and establishes p90RS kinase as a link between hypoxia and the acidic microenvironment of tumors.
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Affiliation(s)
- Fabrice Lucien
- Immunology Division, Department of Pediatrics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Canada
| | - Karine Brochu-Gaudreau
- Immunology Division, Department of Pediatrics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Canada
| | - Dominique Arsenault
- Immunology Division, Department of Pediatrics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Canada
| | - Kelly Harper
- Immunology Division, Department of Pediatrics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Canada
| | - Claire M. Dubois
- Immunology Division, Department of Pediatrics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Canada
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Delivoria-Papadopoulos M, Ashraf QM, Mishra OP. Mechanism of CaM kinase IV activation during hypoxia in neuronal nuclei of the cerebral cortex of newborn piglets: the role of Src kinase. Neurochem Res 2011; 36:1512-9. [PMID: 21516343 DOI: 10.1007/s11064-011-0477-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/11/2011] [Indexed: 12/11/2022]
Abstract
The present study aims to investigate the mechanism of CaM kinase IV activation during hypoxia and tests the hypothesis that hypoxia-induced increased activity of CaM kinase IV is due to Src kinase mediated increased tyrosine phosphorylation of calmodulin and CaM kinase IV in neuronal nuclei of the cerebral cortex of newborn piglets. Piglets were divided into normoxic (Nx, n = 5), hypoxic (Hx, F(i)O(2) of 0.07 for 1 h, n = 5) and hypoxic-pretreated with Src kinase inhibitor PP2 (Hx-Srci, n = 5) groups. Src inhibitor was administered (1.0 mg/kg, I.V.) 30 min prior to hypoxia. Neuronal nuclei were isolated and purified, and tyrosine phosphorylation of calmodulin (Tyr(99)) and CaM kinase IV determined by Western blot using anti-phospho-(pTyr(99))-calmodulin, anti-pTyrosine and anti-CaM kinase IV antibodies. The activity of CaM kinase IV and its consequence the phosphorylation of CREB protein at Ser(133) were determined. Hypoxia resulted in increased tyrosine phosphorylation of calmodulin at Tyr(99), tyrosine phosphorylation of CaM kinase IV, activity of CaM kinase IV and phosphorylation of CREB protein at Ser(133). The data show that administration of Src kinase inhibitor PP2 prevented the hypoxia-induced increased tyrosine phosphorylation of calmodulin (Tyr(99)) and tyrosine phosphorylation of CaM.kinase IV as well as the activity of CaM kinase IV and CREB phosphorylation at Ser(133). We conclude that the mechanism of hypoxia-induced increased activation of CaM kinase IV is mediated by Src kinase-dependent tyrosine phosphorylation of the enzyme and its activator calmodulin. We propose that Tyr(99) phosphorylated calmodulin, as compared to non-phosphorylated, binds with a higher affinity at the calmodulin binding site (rich in basic amino acids) of CaM kinase IV leading to increased activation of CaM kinase IV. Similarly, tyrosine phosphorylated CaM kinase IV binds its substrate with a higher affinity and thus increased tyrosine phosphorylation leads to increased activation of CaM kinase IV resulting in increased CREB phosphorylation that triggers increased transcription of proapoptotic proteins that initiate hypoxic neuronal death.
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Affiliation(s)
- Maria Delivoria-Papadopoulos
- Department of Pediatrics, Drexel University College of Medicine and St. Christopher's Hospital for Children, 245 N 15th Street, New College Building, Room 7410, Mail Stop 1029, Philadelphia, PA 19102, USA.
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11
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Delivoria-Papadopoulos M, Ashraf QM, Mishra OP. Brain tissue energy dependence of CaM kinase IV cascade activation during hypoxia in the cerebral cortex of newborn piglets. Neurosci Lett 2011; 491:113-7. [PMID: 21236315 DOI: 10.1016/j.neulet.2011.01.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Revised: 12/29/2010] [Accepted: 01/06/2011] [Indexed: 10/18/2022]
Abstract
The present study aims to investigate the dependence of CaM kinase IV cascade activation during hypoxia and tests the hypothesis that hypoxia-induced tyrosine phosphorylation of CaM and CaM kinase IV, activation of CaM kinase IV and phosphorylation of CREB protein during hypoxia increases as a function of increase in cerebral tissue hypoxia as measured by decrease in tissue ATP and phosphocreatine (PCr). 3-5 days old newborn piglets were divided into normoxic (Nx, FiO₂ of 0.21 for 1h) and hypoxic (Hx, FiO₂ of 0.07 for 1h) groups. Cerebral tissue hypoxia was documented by determining the levels of high energy phosphates ATP and phosphocreatine (PCr). Cerebral cortical neuronal nuclei were isolated and purified, and tyrosine phosphorylation of calmodulin (Tyr⁹⁹), the activator of CaM kinase IV, and CaM kinase IV determined by Western blot using anti-phospho-(pTyr⁹⁹)-calmodulin, anti-pTyrosine and anti-CaM kinase IV antibodies. The activity of CaM kinase IV and its consequence the phosphorylation of CREB protein at Ser¹³³ were determined. The levels of ATP (μmole/g brain) ranged from 3.48 to 5.28 in Nx, and 0.41 to 2.26 in Hx. The levels of PCr (μmole/g brain) ranged from 2.46 to 3.91 in Nx and 0.72 to 1.20 in Hx. The pTyr⁹⁹ calmodulin (OD x mm²) ranged from 20.35 to 54.47.60 in Nx, and 84.52 to 181.42 in Hx (r²=0.5309 vs ATP and r²=0.6899 vs PCr). Expression of tyrosine phosphorylated CaM kinase IV ranged from 32.86 to 82.46 in Nx and 96.70 to 131.62 in Hx (r²=0.5132 vs ATP and r²=0.4335 vs PCr). The activity of CaM kinase IV (pmole/mg protein/min) ranged from 1263 to 3448 in Nx and 3767 to 6633 in Hx (r²=0.7113 vs ATP and r²=0.6182 vs PCr). The expression of p-CREB at Ser¹³³ ranged from 44.26 to 70.28 in Nx and 82.70 to 182.86 in Hx (r²=0.6621 vs ATP and r²=0.5485 vs PCr). The data show that hypoxia results in increased tyrosine phosphorylation of calmodulin (Tyr⁹⁹), increased tyrosine phosphorylation of CaM kinase IV, increased activity of CaM kinase IV and increased phosphorylation of CREB at Ser¹³³ as an inverse function of cerebral concentration of high energy phosphates, ATP and PCr. We conclude that the hypoxia-induced increased activation of CaM kinase IV cascade increases with the increase in the degree of cerebral tissue hypoxia as measured by cerebral tissue high energy phosphates in a curvilinear manner. The tyrosine kinases (Src kinase and EGFR kinase) mediated activation of CaM kinase IV cascade potentially results in increased CREB phosphorylation that triggers transcription of proapoptotic proteins during hypoxia.
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Affiliation(s)
- Maria Delivoria-Papadopoulos
- Department of Pediatrics, Drexel University College of Medicine and St. Christopher's, Hospital for Children, Philadelphia, PA 19102, USA.
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