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Hancock WD, Lei X, Clines GA, Tusing YG, Nozell SE, Ramanadham S. Ca 2+-independent phospholipase A 2β-derived PGE 2 contributes to osteogenesis. Prostaglandins Other Lipid Mediat 2022; 158:106605. [PMID: 34923151 PMCID: PMC8753754 DOI: 10.1016/j.prostaglandins.2021.106605] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 12/13/2021] [Accepted: 12/14/2021] [Indexed: 02/03/2023]
Abstract
Bone modeling can be modulated by lipid signals such as arachidonic acid (AA) and its cyclooxygenase 2 (COX2) metabolite, prostaglandin E2 (PGE2), which are recognized mediators of optimal bone formation. Hydrolysis of AA from membrane glycerophospholipids is catalyzed by phospholipases A2 (PLA2s). We reported that mice deficient in the Ca2+- independent PLA2beta (iPLA2β), encoded by Pla2g6, exhibit a low bone phenotype, but the cause for this remains to be identified. Here, we examined the mechanistic and molecular roles of iPLA2β in bone formation using bone marrow stromal cells and calvarial osteoblasts from WT and iPLA2β-deficient mice, and the MC3T3-E1 osteoblast precursor cell line. Our data reveal that transcription of osteogenic factors (Bmp2, Alpl, and Runx2) and osteogenesis are decreased with iPLA2β-deficiency. These outcomes are corroborated and recapitulated in WT cells treated with a selective inhibitor of iPLA2 β (10 μM S-BEL), and rescued in iPLA2β-deficient cells by additions of 10 μM PGE2. Further, under osteogenic conditions we find that PGE2 production is through iPLA2β activity and that this leads to induction of Runx2 and iPLA2β transcription. These findings reveal a strong link between osteogenesis and iPLA2β-derived lipids and raise the intriguing possibility that iPLA2β-derived PGE2 participates in osteogenesis and in the regulation of Runx2 and also iPLA2β.
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Affiliation(s)
- William D Hancock
- Department of Biochemistry and Molecular Biology Virginia Commonwealth University, Richmond, VA, USA
| | - Xiaoyong Lei
- Department of Cell, Developmental, and Integrative Biology, USA; Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Gregory A Clines
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Ying G Tusing
- Department of Cell, Developmental, and Integrative Biology, USA; Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Susan E Nozell
- Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Sasanka Ramanadham
- Department of Cell, Developmental, and Integrative Biology, USA; Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL, USA.
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2
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Wielgos ME, Zhang Z, Rajbhandari R, Cooper TS, Zeng L, Forero A, Esteva FJ, Osborne CK, Schiff R, LoBuglio AF, Nozell SE, Yang ES. Trastuzumab-Resistant HER2 + Breast Cancer Cells Retain Sensitivity to Poly (ADP-Ribose) Polymerase (PARP) Inhibition. Mol Cancer Ther 2018; 17:921-930. [PMID: 29592880 DOI: 10.1158/1535-7163.mct-17-0302] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 08/29/2017] [Accepted: 02/23/2018] [Indexed: 01/24/2023]
Abstract
HER2-targeted therapies, such as trastuzumab, have increased the survival rates of HER2+ breast cancer patients. However, despite these therapies, many tumors eventually develop resistance to these therapies. Our lab previously reported an unexpected sensitivity of HER2+ breast cancer cells to poly (ADP-ribose) polymerase inhibitors (PARPi), agents that target homologous recombination (HR)-deficient tumors, independent of a DNA repair deficiency. In this study, we investigated whether HER2+ trastuzumab-resistant (TR) breast cancer cells were susceptible to PARPi and the mechanism behind PARPi induced cytotoxicity. We demonstrate that the PARPi ABT-888 (veliparib) decreased cell survival in vitro and tumor growth in vivo of HER2+ TR breast cancer cells. PARP-1 siRNA confirmed that cytotoxicity was due, in part, to PARP-1 inhibition. Furthermore, PARP-1 silencing had variable effects on the expression of several NF-κB-regulated genes. In particular, silencing PARP-1 inhibited NF-κB activity and reduced p65 binding at the IL8 promoter, which resulted in a decrease in IL8 mRNA and protein expression. Our results provide insight in the potential mechanism by which PARPi induces cytotoxicity in HER2+ breast cancer cells and support the testing of PARPi in patients with HER2+ breast cancer resistant to trastuzumab. Mol Cancer Ther; 17(5); 921-30. ©2018 AACR.
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Affiliation(s)
- Monica E Wielgos
- Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Zhuo Zhang
- Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Rajani Rajbhandari
- Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Tiffiny S Cooper
- Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Ling Zeng
- Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Andres Forero
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Francisco J Esteva
- Breast Medical Oncology Program, NYU Cancer Institute, New York, New York
| | - C Kent Osborne
- Lester and Sue Smith Breast Cancer, Baylor College of Medicine, Houston, Texas
- Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas
- Department of Medicine, Baylor College of Medicine, Houston, Texas
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas
| | - Rachel Schiff
- Lester and Sue Smith Breast Cancer, Baylor College of Medicine, Houston, Texas
- Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas
- Department of Medicine, Baylor College of Medicine, Houston, Texas
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas
| | - Albert F LoBuglio
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Susan E Nozell
- Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, Alabama
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Eddy S Yang
- Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, Alabama.
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, Alabama
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3
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Meares GP, Rajbhandari R, Gerigk M, Tien CL, Chang C, Fehling SC, Rowse A, Mulhern KC, Nair S, Gray GK, Berbari NF, Bredel M, Benveniste EN, Nozell SE. MicroRNA-31 is required for astrocyte specification. Glia 2018; 66:987-998. [PMID: 29380422 DOI: 10.1002/glia.23296] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 10/30/2017] [Accepted: 01/08/2018] [Indexed: 12/21/2022]
Abstract
Previously, we determined microRNA-31 (miR-31) is a noncoding tumor suppressive gene frequently deleted in glioblastoma (GBM); miR-31 suppresses tumor growth, in part, by limiting the activity of NF-κB. Herein, we expand our previous studies by characterizing the role of miR-31 during neural precursor cell (NPC) to astrocyte differentiation. We demonstrate that miR-31 expression and activity is suppressed in NPCs by stem cell factors such as Lin28, c-Myc, SOX2 and Oct4. However, during astrocytogenesis, miR-31 is induced by STAT3 and SMAD1/5/8, which mediate astrocyte differentiation. We determined miR-31 is required for terminal astrocyte differentiation, and that the loss of miR-31 impairs this process and/or prevents astrocyte maturation. We demonstrate that miR-31 promotes astrocyte development, in part, by reducing the levels of Lin28, a stem cell factor implicated in NPC renewal. These data suggest that miR-31 deletions may disrupt astrocyte development and/or homeostasis.
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Affiliation(s)
- Gordon P Meares
- Departments of Microbiology, Immunology and Cell Biology, West Virginia University, Morgantown, West Virginia, 26506
| | - Rajani Rajbhandari
- Departments of Radiation Oncology, University of Alabama at Birmingham, Birmingham, Alabama, 35294
| | - Magda Gerigk
- Departments of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, 35294
| | - Chih-Liang Tien
- Departments of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, 35294
| | - Chenbei Chang
- Departments of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, 35294
| | - Samuel C Fehling
- Departments of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, 35294
| | - Amber Rowse
- Departments of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, 35294
| | - Kayln C Mulhern
- Departments of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, 35294
| | - Sindhu Nair
- Departments of Radiation Oncology, University of Alabama at Birmingham, Birmingham, Alabama, 35294
| | - G Kenneth Gray
- Departments of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, 35294
| | - Nicolas F Berbari
- Departments of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana, 46202
| | - Markus Bredel
- Departments of Radiation Oncology, University of Alabama at Birmingham, Birmingham, Alabama, 35294
| | - Etty N Benveniste
- Departments of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, 35294
| | - Susan E Nozell
- Departments of Radiation Oncology, University of Alabama at Birmingham, Birmingham, Alabama, 35294
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4
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Lai YJ, Tsai JC, Tseng YT, Wu MS, Liu WS, Lam HI, Yu JH, Nozell SE, Benveniste EN. Small G protein Rac GTPases regulate the maintenance of glioblastoma stem-like cells in vitro and in vivo. Oncotarget 2017; 8:18031-18049. [PMID: 28160553 PMCID: PMC5392305 DOI: 10.18632/oncotarget.14949] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 01/03/2017] [Indexed: 12/31/2022] Open
Abstract
Glioblastoma is the most common and aggressive malignant brain tumor in adults. The existence of glioblastoma stem cells (GSCs) or stem-like cells (stemloids) may account for its invasiveness and high recurrence. Rac proteins belong to the Rho small GTPase subfamily which regulates cell movement, proliferation, and survival. To investigate whether Rac proteins can serve as therapeutic targets for glioblastoma, especially for GSCs or stemloids, we examined the potential roles of Rac1, Rac2 and Rac3 on the properties of tumorspheres derived from glioblastoma cell lines. Tumorspheres are thought to be glioblastoma stem-like cells. We showed that Rac proteins promote the STAT3 and ERK activation and enhance cell proliferation and colony formation of glioblastoma stem-like cells. Knockdown of Rac proteins reduces the expression of GSC markers, such as CD133 and Sox2. The in vivo effects of Rac proteins in glioblastoma were further studied in zebrafish and in the mouse xenotransplantation model. Knocking-down Rac proteins abolished the angiogenesis effect induced by the injected tumorspheres in zebrafish model. In the CD133+-U373-tumorsphere xenotransplanted mouse model, suppression of Rac proteins decreased the incidence of tumor formation and inhibited the tumor growth. Moreover, knockdown of Rac proteins reduced the sphere forming efficiency of cells derived from these tumors. In conclusion, not only Rac1 but also Rac2 and 3 are important for glioblastoma tumorigenesis and can serve as the potential therapeutic targets against glioblastoma and its stem-like cells.
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Affiliation(s)
- Yun-Ju Lai
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Jui-Cheng Tsai
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Ying-Ting Tseng
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Meng-Shih Wu
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Wen-Shan Liu
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Hoi-Ian Lam
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Jei-Hwa Yu
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, AL, USA
| | - Susan E Nozell
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, AL, USA
| | - Etty N Benveniste
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, AL, USA
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5
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Rajbhandari R, McFarland BC, Patel A, Gerigk M, Gray GK, Fehling SC, Bredel M, Berbari NF, Kim H, Marks MP, Meares GP, Sinha T, Chuang J, Benveniste EN, Nozell SE. Loss of tumor suppressive microRNA-31 enhances TRADD/NF-κB signaling in glioblastoma. Oncotarget 2016; 6:17805-16. [PMID: 26164206 PMCID: PMC4627347 DOI: 10.18632/oncotarget.4596] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 06/17/2015] [Indexed: 01/09/2023] Open
Abstract
Glioblastomas (GBMs) are deadly tumors of the central nervous system. Most GBM exhibit homozygous deletions of the CDKN2A and CDKN2B tumor suppressors at 9p21.3, although loss of CDKN2A/B alone is insufficient to drive gliomagenesis. MIR31HG, which encodes microRNA-31 (miR-31), is a novel non-coding tumor suppressor positioned adjacent to CDKN2A/B at 9p21.3. We have determined that miR-31 expression is compromised in >72% of all GBM, and for patients, this predicts significantly shortened survival times independent of CDKN2A/B status. We show that miR-31 inhibits NF-κB signaling by targeting TRADD, its upstream activator. Moreover, upon reintroduction, miR-31 significantly reduces tumor burden and lengthens survival times in animal models. As such, our work identifies loss of miR-31 as a novel non-coding tumor-driving event in GBM.
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Affiliation(s)
- Rajani Rajbhandari
- Departments of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Braden C McFarland
- Departments of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Ashish Patel
- Departments of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Magda Gerigk
- Departments of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - G Kenneth Gray
- Departments of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Samuel C Fehling
- Departments of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Markus Bredel
- Radiation Oncology at the University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Nicolas F Berbari
- Departments of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Hyunsoo Kim
- Jackson Laboratory for Genomic Medicine, Farmington, Connecticut, USA
| | - Margaret P Marks
- Departments of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Gordon P Meares
- Departments of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Tanvi Sinha
- Departments of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Jeffrey Chuang
- Jackson Laboratory for Genomic Medicine, Farmington, Connecticut, USA
| | - Etty N Benveniste
- Departments of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Susan E Nozell
- Departments of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
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6
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Abstract
Since we last addressed the roles of NF-κB and JAK/STAT3 signaling in glioblastoma (GBM) 5 years ago, tremendous strides have been made in the understanding of these two pathways in glioma biology. Contributing to prosurvival mechanisms, cancer stem cell maintenance and treatment resistance, both NF-κB and STAT3 have been characterized as major drivers of GBM. In this review, we address general improvements in the molecular understanding of GBM, the structure of NF-κB and STAT3 signaling, the ways in which these pathways contribute to GBM and advances in preclinical and clinical targeting of these two signaling cascades.
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Affiliation(s)
- G Kenneth Gray
- Department of Cell, Developmental and Integrative Biology, 1900 University Blvd, THT 926A, University of Alabama at Birmingham, Birmingham, AL, 35294-0006, USA
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7
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McFarland BC, Gray GK, Nozell SE, Hong SW, Benveniste EN. Activation of the NF-κB pathway by the STAT3 inhibitor JSI-124 in human glioblastoma cells. Mol Cancer Res 2013; 11:494-505. [PMID: 23386688 DOI: 10.1158/1541-7786.mcr-12-0528] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Glioblastoma tumors are characterized by their invasiveness and resistance to therapies. The transcription factor signal transducer and activator of transcription 3 (STAT3) was recently identified as a master transcriptional regulator in the mesenchymal subtype of glioblastoma (GBM), which has generated an increased interest in targeting STAT3. We have evaluated more closely the mechanism of action of one particular STAT3 inhibitor, JSI-124 (cucurbitacin I). In this study, we confirmed that JSI-124 inhibits both constitutive and stimulus-induced Janus kinase 2 (JAK2) and STAT3 phosphorylation, and decreases cell proliferation while inducing apoptosis in cultured GBM cells. However, we discovered that before the inhibition of STAT3, JSI-124 activates the nuclear factor-κB (NF-κB) pathway, via NF-κB p65 phosphorylation and nuclear translocation. In addition, JSI-124 treatment induces the expression of IL-6, IL-8, and suppressor of cytokine signaling (SOCS3) mRNA, which leads to a corresponding increase in IL-6, IL-8, and SOCS3 protein expression. Moreover, the NF-κB-driven SOCS3 expression acts as a negative regulator of STAT3, abrogating any subsequent STAT3 activation and provides a mechanism of STAT3 inhibition after JSI-124 treatment. Chromatin immunoprecipitation analysis confirms that NF-κB p65 in addition to other activating cofactors are found at the promoters of IL-6, IL-8, and SOCS3 after JSI-124 treatment. Using pharmacological inhibition of NF-κB and inducible knockdown of NF-κB p65, we found that JSI-124-induced expression of IL-6, IL-8, and SOCS3 was significantly inhibited, showing an NF-κB-dependent mechanism. Our data indicate that although JSI-124 may show potential antitumor effects through inhibition of STAT3, other off-target proinflammatory pathways are activated, emphasizing that more careful and thorough preclinical investigations must be implemented to prevent potential harmful effects.
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Affiliation(s)
- Braden C McFarland
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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8
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Park KW, Nozell SE, Benveniste EN. Protective role of STAT3 in NMDA and glutamate-induced neuronal death: negative regulatory effect of SOCS3. PLoS One 2012; 7:e50874. [PMID: 23226414 PMCID: PMC3511325 DOI: 10.1371/journal.pone.0050874] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 10/25/2012] [Indexed: 12/20/2022] Open
Abstract
The present study investigates the involvement of the IL-6 family of cytokines, activation of the transcription factor Signal Transducer and Activator of Transcription-3 (STAT3), and the role of Suppressor Of Cytokine Signaling-3 (SOCS3) in regulating excitotoxic neuronal death in vitro. Biochemical evidence demonstrates that in primary cortical neurons and SH-SY5Y neuroblastoma cells, IL-6 cytokine family members, OSM and IL-6 plus the soluble IL-6R (IL-6/R), prevent NMDA and glutamate-induced neuronal toxicity. As well, OSM and IL-6/R induce tyrosine and serine phosphorylation of STAT3 in primary cortical neurons and SH-SY5Y cells. Studies using Pyridine 6 (P6), a pan-JAK inhibitor, demonstrate that the protective effect of OSM and IL-6/R on neuronal death is mediated by the JAK/STAT3 signaling pathway. In parallel to STAT3 phosphorylation, OSM and IL-6/R induce SOCS3 expression at the mRNA and protein level. P6 treatment inhibits SOCS3 expression, indicating that STAT3 is required for OSM and IL-6/R-induced SOCS3 expression. Lentiviral delivery of SOCS3, an inhibitor of STAT3 signaling, into primary neurons and SH-SY5Y cells inhibits OSM and IL-6/R-induced phosphorylation of STAT3, and also reverses the protective effect of OSM and IL-6/R on NMDA and glutamate-induced neurotoxicity in primary cortical neurons. In addition, treatment with IL-6 cytokines increases expression of the anti-apoptotic protein Bcl-xL and induces activation of the Akt signaling pathway, which are also negatively regulated by SOCS3 expression. Thus, IL-6/R and OSM-induced SOCS3 expression may be an important factor limiting the neuroprotective effects of activated STAT3 against NMDA and glutamate-induced neurotoxicity.
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Affiliation(s)
- Keun W. Park
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Susan E. Nozell
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Etty N. Benveniste
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- * E-mail:
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9
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Gong K, Xing D, Li P, Aksut B, Ambalavanan N, Yang Q, Nozell SE, Oparil S, Chen YF. Hypoxia induces downregulation of PPAR-γ in isolated pulmonary arterial smooth muscle cells and in rat lung via transforming growth factor-β signaling. Am J Physiol Lung Cell Mol Physiol 2011; 301:L899-907. [PMID: 21926264 PMCID: PMC3233825 DOI: 10.1152/ajplung.00062.2011] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Accepted: 09/05/2011] [Indexed: 11/22/2022] Open
Abstract
Chronic hypoxia activates transforming growth factor-β (TGF-β) signaling and leads to pulmonary vascular remodeling. Pharmacological activation of peroxisome proliferator-activated receptor-γ (PPAR-γ) has been shown to prevent hypoxia-induced pulmonary hypertension and vascular remodeling in rodent models, suggesting a vasoprotective effect of PPAR-γ under chronic hypoxic stress. This study tested the hypothesis that there is a functional interaction between TGF-β/Smad signaling pathway and PPAR-γ in isolated pulmonary artery small muscle cells (PASMCs) under hypoxic stress. We observed that chronic hypoxia led to a dramatic decrease of PPAR-γ protein expression in whole lung homogenates (rat and mouse) and hypertrophied pulmonary arteries and isolated PASMCs. Using a transgenic model of mouse with inducible overexpression of a dominant-negative mutant of TGF-β receptor type II, we demonstrated that disruption of TGF-β pathway significantly attenuated chronic hypoxia-induced downregulation of PPAR-γ in lung. Similarly, in isolated rat PASMCs, antagonism of TGF-β signaling with either a neutralizing antibody to TGF-β or the selective TGF-β receptor type I inhibitor SB431542 effectively attenuated hypoxia-induced PPAR-γ downregulation. Furthermore, we have demonstrated that TGF-β1 treatment suppressed PPAR-γ expression in PASMCs under normoxia condition. Chromatin immunoprecipitation analysis showed that TGF-β1 treatment significantly increased binding of Smad2/3, Smad4, and the transcriptional corepressor histone deacetylase 1 to the PPAR-γ promoter in PASMCs. Conversely, treatment with the PPAR-γ agonist rosiglitazone attenuated TGF-β1-induced extracellular matrix molecule expression and growth factor in PASMCs. These data provide strong evidence that activation of TGF-β/Smad signaling, via transcriptional suppression of PPAR-γ expression, mediates chronic hypoxia-induced downregulation of PPAR-γ expression in lung.
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MESH Headings
- Animals
- Cell Hypoxia
- Cell Movement
- Cells, Cultured
- Down-Regulation
- Extracellular Matrix/metabolism
- Histone Deacetylase 1/metabolism
- Hypoxia/genetics
- Hypoxia/metabolism
- Lung/blood supply
- Lung/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Myocytes, Smooth Muscle/metabolism
- PPAR gamma/agonists
- PPAR gamma/genetics
- PPAR gamma/metabolism
- Protein Serine-Threonine Kinases/antagonists & inhibitors
- Protein Serine-Threonine Kinases/genetics
- Protein Serine-Threonine Kinases/metabolism
- Pulmonary Artery/metabolism
- Pulmonary Artery/pathology
- Rats
- Rats, Sprague-Dawley
- Receptor, Transforming Growth Factor-beta Type I
- Receptor, Transforming Growth Factor-beta Type II
- Receptors, Transforming Growth Factor beta/antagonists & inhibitors
- Receptors, Transforming Growth Factor beta/genetics
- Receptors, Transforming Growth Factor beta/metabolism
- Signal Transduction
- Smad Proteins/metabolism
- Transcription, Genetic
- Transforming Growth Factor beta/metabolism
- Transforming Growth Factor beta/pharmacology
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Affiliation(s)
- Kaizheng Gong
- Vascular Biology and Hypertension Program, Department of Medicine, University of Alabama at Birmingham, 35294, USA
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10
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McFarland BC, Ma JY, Langford CP, Gillespie GY, Yu H, Zheng Y, Nozell SE, Huszar D, Benveniste EN. Therapeutic potential of AZD1480 for the treatment of human glioblastoma. Mol Cancer Ther 2011; 10:2384-93. [PMID: 22027691 DOI: 10.1158/1535-7163.mct-11-0480] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Aberrant activation of the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway has been implicated in glioblastoma (GBM) progression. To develop a therapeutic strategy to inhibit STAT-3 signaling, we have evaluated the effects of AZD1480, a pharmacologic inhibitor of JAK1 and JAK2. In this study, the in vitro efficacy of AZD1480 was tested in human and murine glioma cell lines. AZD1480 treatment effectively blocks constitutive and stimulus-induced JAK1, JAK2, and STAT-3 phosphorylation in both human and murine glioma cells, and leads to a decrease in cell proliferation and induction of apoptosis. Furthermore, we used human xenograft GBM samples as models for the study of JAK/STAT-3 signaling in vivo, because human GBM samples propagated as xenografts in nude mice retain both the hallmark genetic alterations and the invasive phenotype seen in vivo. In these xenograft tumors, JAK2 and STAT-3 are constitutively active, but levels vary among tumors, which is consistent with the heterogeneity of GBMs. AZD1480 inhibits constitutive and stimulus-induced phosphorylation of JAK2 and STAT-3 in these GBM xenograft tumors in vitro, downstream gene expression, and inhibits cell proliferation. Furthermore, AZD1480 suppresses STAT-3 activation in the glioma-initiating cell population in GBM tumors. In vivo, AZD1480 inhibits the growth of subcutaneous tumors and increases survival of mice bearing intracranial GBM tumors by inhibiting STAT-3 activity, indicating that pharmacologic inhibition of the JAK/STAT-3 pathway by AZD1480 should be considered for study in the treatment of patients with GBM tumors.
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Affiliation(s)
- Braden C McFarland
- Department of Cell Biology, 1918 University Blvd., MCLM 313, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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Xing D, Gong K, Feng W, Nozell SE, Chen YF, Chatham JC, Oparil S. O-GlcNAc modification of NFκB p65 inhibits TNF-α-induced inflammatory mediator expression in rat aortic smooth muscle cells. PLoS One 2011; 6:e24021. [PMID: 21904602 PMCID: PMC3164132 DOI: 10.1371/journal.pone.0024021] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Accepted: 07/28/2011] [Indexed: 11/26/2022] Open
Abstract
Background We have shown that glucosamine (GlcN) or O-(2-acetamido-2-deoxy-D-glucopyranosylidene)amino-N-phenylcarbamate (PUGNAc) treatment augments O-linked-N-acetylglucosamine (O-GlcNAc) protein modification and attenuates inflammatory mediator expression, leukocyte infiltration and neointima formation in balloon injured rat carotid arteries and have identified the arterial smooth muscle cell (SMC) as the target cell in the injury response. NFκB signaling has been shown to mediate the expression of inflammatory genes and neointima formation in injured arteries. Phosphorylation of the p65 subunit of NFκB is required for the transcriptional activation of NFκB. This study tested the hypothesis that GlcN or PUGNAc treatment protects vascular SMCs against tumor necrosis factor (TNF)-α induced inflammatory stress by enhancing O-GlcNAcylation and inhibiting TNF-α induced phosphorylation of NFκB p65, thus inhibiting NFκB signaling. Methodology/Principal Findings Quiescent rat aortic SMCs were pretreated with GlcN (5 mM), PUGNAc (10−4 M) or vehicle and then stimulated with TNF-α (10 ng/ml). Both treatments inhibited TNF-α-induced expression of chemokines [cytokine-induced neutrophil chemoattractant (CINC)-2β and monocyte chemotactic protein (MCP)-1] and adhesion molecules [vascular cell adhesion molecule (VCAM)-1 and P-Selectin]. Both treatments inhibited TNF-α induced NFκB p65 activation and promoter activity, increased NFκB p65 O-GlcNAcylation and inhibited NFκB p65 phosphorylation at Serine 536, thus promoting IκBα binding to NFκB p65. Conclusions There is a reciprocal relationship between O-GlcNAcylation and phosphorylation of NFκB p65, such that increased NFκB p65 O-GlcNAc modification inhibits TNF-α-Induced expression of inflammatory mediators through inhibition of NFκB p65 signaling. These findings provide a mechanistic basis for our previous observations that GlcN and PUGNAc treatments inhibit inflammation and remodeling induced by acute endoluminal arterial injury.
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Affiliation(s)
- Dongqi Xing
- Vascular Biology and Hypertension Program, Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America.
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Zhao X, Laver T, DeVos A, Twitty G, DeVos M, Benveniste EN, Nozell SE. An NF-κB p65-cIAP2 link is necessary for mediating resistance to TNF-α induced cell death in gliomas. J Neurooncol 2011; 102:367-81. [PMID: 21279667 PMCID: PMC3736577 DOI: 10.1007/s11060-010-0346-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Accepted: 08/06/2010] [Indexed: 01/20/2023]
Abstract
Malignant gliomas are diffusively infiltrative and remain among the deadliest of all cancers. NF-κB is a transcription factor that mediates cell growth, migration and invasion, angiogenesis and resistance to apoptosis. Normally, the activity of NF-κB is tightly regulated by numerous mechanisms. However, in many cancers, NF-κB is constitutively activated and may function as a tumor promoter. Herein, we show that in gliomas, NF-κB is constitutively activated and the levels of cIAP2, Bcl-2, Bcl-xL and Survivin are elevated. These genes are regulated by NF-κB and can inhibit apoptosis. To understand the potential role of NF-κB p65 in suppressing apoptosis, we generated human glioma cell lines that inducibly express shRNA molecules specific for p65. We demonstrate that in the absence of p65, TNF-α induced cIAP2 expression is significantly reduced while the levels of Bcl-2, Bcl-xL and Survivin are not affected. These data suggest that of these genes, only cIAP2 is a direct target of p65, which was confirmed using RT-PCR and chromatin immunoprecipitation (ChIP) assays. By reducing the levels of p65 and/or cIAP2 levels, we demonstrate that the levels of RIP poly-ubiquitination are reduced, and that p65-deficient glioma cells are more sensitive to the cytotoxic effects of TNF-α. Specifically, in the presence of TNF-α glioma cells lacking p65 and/or cIAP2 showed cellular proliferation defects and underwent cell death. These data suggest that NF-κB and/or cIAP2 may be therapeutically relevant targets for the treatment of malignant gliomas.
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Affiliation(s)
| | | | - Annelies DeVos
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0005
| | - George Twitty
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0005
| | - Marijke DeVos
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0005
| | - Etty N. Benveniste
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0005
| | - Susan E. Nozell
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0005
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Oliva CR, Nozell SE, Diers A, McClugage SG, Sarkaria JN, Markert JM, Darley-Usmar VM, Bailey SM, Gillespie GY, Landar A, Griguer CE. Acquisition of temozolomide chemoresistance in gliomas leads to remodeling of mitochondrial electron transport chain. J Biol Chem 2010; 285:39759-67. [PMID: 20870728 DOI: 10.1074/jbc.m110.147504] [Citation(s) in RCA: 146] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Temozolomide (TMZ) is an oral alkylating agent used for the treatment of high-grade gliomas. Acquired chemoresistance is a severe limitation to this therapy with more than 90% of recurrent gliomas showing no response to a second cycle of chemotherapy. Efforts to better understand the underlying mechanisms of acquired chemoresistance to TMZ and potential strategies to overcome chemoresistance are, therefore, critically needed. TMZ methylates nuclear DNA and induces cell death; however, the impact on mitochondria DNA (mtDNA) and mitochondrial bioenergetics is not known. Herein, we tested the hypothesis that TMZ-mediated alterations in mtDNA and respiratory function contribute to TMZ-dependent acquired chemoresistance. Using an in vitro model of TMZ-mediated acquired chemoresistance, we report 1) a decrease in mtDNA copy number and the presence of large heteroplasmic mtDNA deletions in TMZ-resistant glioma cells, 2) remodeling of the entire electron transport chain with significant decreases of complexes I and V and increases of complexes II/III and IV, and 3) pharmacologic and genetic manipulation of cytochrome c oxidase, which restores sensitivity to TMZ-dependent apoptosis in resistant glioma cells. Importantly, human primary and recurrent pairs of glioblastoma multiforme (GBM) biopsies as well as primary and TMZ-resistant GBM xenograft lines exhibit similar remodeling of the ETC. Overall these results suggest that TMZ-dependent acquired chemoresistance may be due to a mitochondrial adaptive response to TMZ genotoxic stress with a major contribution from cytochrome c oxidase. Thus, abrogation of this adaptive response may reverse chemoresistance and restore sensitivity to TMZ, providing a strategy for improved therapeutic outcomes in GBM patients.
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Affiliation(s)
- Claudia R Oliva
- Department of Surgery, Division of Neurosurgery, University of Alabama at Birmingham, Alabama 35294-0006, USA
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Abstract
Glioblastoma remains the most clinically challenging tumor of the CNS, as evidenced by the dismal change in overall survival over the past 50 years. However, recent advances in high-throughput screening techniques have given rise to a wealth of new information regarding the aberrant signaling pathways that drive the tumor phenotype. Two of these so-called 'oncopathways' are NF-kappaB and JAK/STAT. This review will describe the basic mechanisms of these pathways, explore the relevance of NF-kappaB and JAK/STAT signaling in glioblastoma, and look ahead to experimental compounds that will integrate our knowledge of these pathways into existing therapies.
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Affiliation(s)
- George P Atkinson
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, AL 35294-0005, USA
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Laver T, Nozell SE, Benveniste EN. IFN-β-Mediated Inhibition of IL-8 Expression Requires the ISGF3 Components Stat1, Stat2, and IRF-9. J Interferon Cytokine Res 2008; 28:13-23. [DOI: 10.1089/jir.2007.0062] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Travis Laver
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, AL 35294-0005
| | - Susan E. Nozell
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, AL 35294-0005
| | - Etty N. Benveniste
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, AL 35294-0005
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Ripps H, Peachey NS, Xu X, Nozell SE, Smith SB, Liou GI. The rhodopsin cycle is preserved in IRBP "knockout" mice despite abnormalities in retinal structure and function. Vis Neurosci 2000; 17:97-105. [PMID: 10750831 DOI: 10.1017/s095252380017110x] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In the vertebrate retina, vision is initiated and maintained by the photolysis and regeneration, respectively, of light-sensitive pigments in the disk membranes of the photoreceptor outer segments. This cyclical process depends on an exchange of retinoids between the photoreceptors and the retinal pigment epithelium (RPE). There is a great deal of indirect evidence that the transport of retinoids between these cellular compartments is mediated by the interphotoreceptor retinoid-binding protein (IRBP), a large glycoprotein synthesized in the photoreceptors and extruded into the interphotoreceptor matrix (IPM) that fills the subretinal space. Nevertheless, a number of in vitro experiments have demonstrated that an intermembranous transfer of retinoids can occur through an aqueous medium independent of any retinoid-binding protein. This led to the suggestion that IRBP may play the more passive role of an extracellular buffer, serving to prevent the degradation and potentially cytotoxic effects of free retinoids when large amounts are released into the IPM. We have studied the structural and functional properties of transgenic mice in which homologous recombination was used to delete the IRBP gene. Light- and electron-microscopic examination of the retinas of "knockout" (IRBP-/-) mice revealed a significant loss of photoreceptor nuclei, and profound changes in the structure and organization of the receptor outer segments. Consistent with these observations, electroretinographic recordings showed a marked reduction in response amplitude for both rod- and cone-mediated potentials. However, despite the histological and electrophysiological changes, there was no evidence of gross abnormalities in the visual cycle. After bleaching a significant fraction of the available rhodopsin, electroretinogram amplitude and rhodopsin density gradually increased toward their pre-bleach levels, and the rates of recovery were even more rapid than those seen in wild-type (IRBP+/+) mice.
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Affiliation(s)
- H Ripps
- Department of Ophthalmology and Visual Sciences, University of Illinois College of Medicine, Chicago, USA
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