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Coelho BP, Fernandes CFDL, Boccacino JM, Souza MCDS, Melo-Escobar MI, Alves RN, Prado MB, Iglesia RP, Cangiano G, Mazzaro GLR, Lopes MH. Multifaceted WNT Signaling at the Crossroads Between Epithelial-Mesenchymal Transition and Autophagy in Glioblastoma. Front Oncol 2020; 10:597743. [PMID: 33312955 PMCID: PMC7706883 DOI: 10.3389/fonc.2020.597743] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [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: 08/21/2020] [Accepted: 10/19/2020] [Indexed: 12/17/2022] Open
Abstract
Tumor cells can employ epithelial-mesenchymal transition (EMT) or autophagy in reaction to microenvironmental stress. Importantly, EMT and autophagy negatively regulate each other, are able to interconvert, and both have been shown to contribute to drug-resistance in glioblastoma (GBM). EMT has been considered one of the mechanisms that confer invasive properties to GBM cells. Autophagy, on the other hand, may show dual roles as either a GBM-promoter or GBM-suppressor, depending on microenvironmental cues. The Wingless (WNT) signaling pathway regulates a plethora of developmental and biological processes such as cellular proliferation, adhesion and motility. As such, GBM demonstrates deregulation of WNT signaling in favor of tumor initiation, proliferation and invasion. In EMT, WNT signaling promotes induction and stabilization of different EMT activators. WNT activity also represses autophagy, while nutrient deprivation induces β-catenin degradation via autophagic machinery. Due to the importance of the WNT pathway to GBM, and the role of WNT signaling in EMT and autophagy, in this review we highlight the effects of the WNT signaling in the regulation of both processes in GBM, and discuss how the crosstalk between EMT and autophagy may ultimately affect tumor biology.
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Affiliation(s)
- Bárbara Paranhos Coelho
- Laboratory of Neurobiology and Stem Cells, Institute of Biomedical Sciences, Department of Cell and Developmental Biology, University of São Paulo, São Paulo, Brazil
| | - Camila Felix de Lima Fernandes
- Laboratory of Neurobiology and Stem Cells, Institute of Biomedical Sciences, Department of Cell and Developmental Biology, University of São Paulo, São Paulo, Brazil
| | - Jacqueline Marcia Boccacino
- Laboratory of Neurobiology and Stem Cells, Institute of Biomedical Sciences, Department of Cell and Developmental Biology, University of São Paulo, São Paulo, Brazil
| | - Maria Clara da Silva Souza
- Laboratory of Neurobiology and Stem Cells, Institute of Biomedical Sciences, Department of Cell and Developmental Biology, University of São Paulo, São Paulo, Brazil
| | - Maria Isabel Melo-Escobar
- Laboratory of Neurobiology and Stem Cells, Institute of Biomedical Sciences, Department of Cell and Developmental Biology, University of São Paulo, São Paulo, Brazil
| | - Rodrigo Nunes Alves
- Laboratory of Neurobiology and Stem Cells, Institute of Biomedical Sciences, Department of Cell and Developmental Biology, University of São Paulo, São Paulo, Brazil
| | - Mariana Brandão Prado
- Laboratory of Neurobiology and Stem Cells, Institute of Biomedical Sciences, Department of Cell and Developmental Biology, University of São Paulo, São Paulo, Brazil
| | - Rebeca Piatniczka Iglesia
- Laboratory of Neurobiology and Stem Cells, Institute of Biomedical Sciences, Department of Cell and Developmental Biology, University of São Paulo, São Paulo, Brazil
| | - Giovanni Cangiano
- Laboratory of Neurobiology and Stem Cells, Institute of Biomedical Sciences, Department of Cell and Developmental Biology, University of São Paulo, São Paulo, Brazil
| | - Giulia La Rocca Mazzaro
- Laboratory of Neurobiology and Stem Cells, Institute of Biomedical Sciences, Department of Cell and Developmental Biology, University of São Paulo, São Paulo, Brazil
| | - Marilene Hohmuth Lopes
- Laboratory of Neurobiology and Stem Cells, Institute of Biomedical Sciences, Department of Cell and Developmental Biology, University of São Paulo, São Paulo, Brazil
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Abstract
The members of the BCL-2 associated athanogene (BAG) family participate in the regulation of a variety of interrelated physiological processes, such as autophagy, apoptosis, and protein homeostasis. Under normal circumstances, the six BAG members described in mammals (BAG1-6) principally assist the 70 kDa heat-shock protein (HSP70) in protein folding; however, their role as oncogenes is becoming increasingly evident. Deregulation of the BAG multigene family has been associated with cell transformation, tumor recurrence, and drug resistance. In addition to BAG overexpression, BAG members are also involved in many oncogenic protein-protein interactions (PPIs). As such, either the inhibition of overloading BAGs or of specific BAG-client protein interactions could have paramount therapeutic value. In this review, we will examine the role of each BAG family member in different malignancies, focusing on their modular structure, which enables interaction with a variety of proteins to exert their pro-tumorigenic role. Lastly, critical remarks on the unmet needs for proposing effective BAG inhibitors will be pointed out.
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Affiliation(s)
- Elena Mariotto
- Department of Woman's and Child's Health, University of Padova, Via Giustiniani 2, 35127 Padova, Italy; Fondazione Istituto di Ricerca Pediatrica Città della Speranza, Corso Stati Uniti 4, 35128 Padova, Italy.
| | - Giampietro Viola
- Department of Woman's and Child's Health, University of Padova, Via Giustiniani 2, 35127 Padova, Italy; Fondazione Istituto di Ricerca Pediatrica Città della Speranza, Corso Stati Uniti 4, 35128 Padova, Italy
| | - Carlo Zanon
- Fondazione Istituto di Ricerca Pediatrica Città della Speranza, Corso Stati Uniti 4, 35128 Padova, Italy
| | - Sanja Aveic
- Neuroblastoma Laboratory, Fondazione Istituto di Ricerca Pediatrica Città della Speranza, Corso Stati Uniti 4, 35128 Padova, Italy
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Huang W, Liu Z, Zhou G, Tian A, Sun N. Magnetic gold nanoparticle-mediated small interference RNA silencing Bag-1 gene for colon cancer therapy. Oncol Rep 2015; 35:978-84. [PMID: 26717967 DOI: 10.3892/or.2015.4453] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 10/19/2015] [Indexed: 11/06/2022] Open
Abstract
Bcl-2-associated athanogene 1 (Bag-1) is a positive regulator of Bcl-2 which is an anti-apoptotic gene. Bag-1 was very slightly expressed in normal tissues, but often highly expressed in many tumor tissues, particularly in colon cancer, which can promote metastasis, poor prognosis and anti-apoptotic function of colon cancer. We prepared and evaluated magnetic gold nanoparticle/Bag-1 siRNA recombinant plasmid complex, a gene therapy system, which can transfect cells efficiently, for both therapeutic effect and safety in vitro mainly by electrophoretic mobility shift assays, flow cytometric analyses, cell viability assays, western blot analyses and RT-PCR (real-time) assays. Magnetic gold nanoparticle/Bag-1 siRNA recombinant plasmid complex was successfully transfected into LoVo colon cancer cells and the exogenous gene was expressed in the cells. Flow cytometric results showed apoptosis rate was significantly increased. In MTT assays, magnetic gold nanoparticles revealed lower cytotoxicity than Lipofectamine 2000 transfection reagents (P<0.05). Both in western blot analyses and RT-PCR assays, magnetic gold nanoparticle/Bag-1 siRNA recombinant plasmid complex transfected cells demonstrated expression of Bag-1 mRNA (P<0.05) and protein (P<0.05) was decreased. In further study, c-myc and β-catenin which are main molecules of Wnt/β‑catenin pathway were decreased when Bag-1 were silenced in nanoparticle plasmid complex transfected LoVo cells. These results suggest that magnetic gold nanoparticle mediated siRNA silencing Bag-1 is an effective gene therapy method for colon cancer.
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Affiliation(s)
- Wenbai Huang
- Department of General Surgery, Qilu Hospital of Shandong University, Jinan, Shandong 200012, P.R. China
| | - Zhan'ao Liu
- Department of General Surgery, Qilu Hospital of Shandong University, Jinan, Shandong 200012, P.R. China
| | - Guanzhou Zhou
- Department of General Surgery, Qilu Hospital of Shandong University, Jinan, Shandong 200012, P.R. China
| | - Ailing Tian
- Department of General Surgery, Qilu Hospital of Shandong University, Jinan, Shandong 200012, P.R. China
| | - Nianfeng Sun
- Department of General Surgery, Qilu Hospital of Shandong University, Jinan, Shandong 200012, P.R. China
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Beyeler S, Joly S, Fries M, Obermair FJ, Burn F, Mehmood R, Tabatabai G, Raineteau O. Targeting the bHLH transcriptional networks by mutated E proteins in experimental glioma. Stem Cells 2015; 32:2583-95. [PMID: 24965159 DOI: 10.1002/stem.1776] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [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: 12/10/2013] [Revised: 05/06/2014] [Accepted: 05/19/2013] [Indexed: 01/15/2023]
Abstract
Glioblastomas (GB) are aggressive primary brain tumors. Helix-loop-helix (HLH, ID proteins) and basic HLH (bHLH, e.g., Olig2) proteins are transcription factors that regulate stem cell proliferation and differentiation throughout development and into adulthood. Their convergence on many oncogenic signaling pathways combined with the observation that their overexpression in GB correlates with poor clinical outcome identifies these transcription factors as promising therapeutic targets. Important dimerization partners of HLH/bHLH proteins are E proteins that are necessary for nuclear translocation and DNA binding. Here, we overexpressed a wild type or a dominant negative form of E47 (dnE47) that lacks its nuclear localization signal thus preventing nuclear translocation of bHLH proteins in long-term glioma cell lines and in glioma-initiating cell lines and analyzed the effects in vitro and in vivo. While overexpression of E47 was sufficient to induce apoptosis in absence of bHLH proteins, dnE47 was necessary to prevent nuclear translocation of Olig2 and to achieve similar proapoptotic responses. Transcriptional analyses revealed downregulation of the antiapoptotic gene BCL2L1 and the proproliferative gene CDC25A as underlying mechanisms. Overexpression of dnE47 in glioma-initiating cell lines with high HLH and bHLH protein levels reduced sphere formation capacities and expression levels of Nestin, BCL2L1, and CDC25A. Finally, the in vivo induction of dnE47 expression in established xenografts prolonged survival. In conclusion, our data introduce a novel approach to jointly neutralize HLH and bHLH transcriptional networks activities, and identify these transcription factors as potential targets in glioma.
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Affiliation(s)
- Sarah Beyeler
- Brain Research Institute, University of Zurich/Swiss Federal Institute of Technology Zurich, Zurich, Switzerland
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Huang B, Zhou H, Lang X, Liu Z, Xiong F, Wang S. Expression of BAG-1 is closely related to cell differentiation and TNM stage in esophageal cancer and its downregulation inhibits the proliferation and invasion of human esophageal carcinoma cells. Oncol Rep 2014; 32:1441-6. [PMID: 25069471 DOI: 10.3892/or.2014.3356] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 06/13/2014] [Indexed: 11/05/2022] Open
Abstract
The aim of the present study was to explore the correlation of BAG-1 with clinical characteristics of esophageal cancer and its effects on the proliferation, invasion and apoptosis of the esophageal carcinoma cell line Eca109. Therefore, the expression of BAG-1 was assessed in esophageal carcinoma tumor tissues and adjacent normal esophageal tissues. The siRNA vector of BAG-1 was constructed and transfected into the Eca109 cell line, and then fluorescence microscopy was used to evaluate the transfection efficiency. MTT and Transwell assays were used to study cell proliferation and invasive activity, and the apoptosis rate was assessed by flow cytometry. Western blotting was adopted to assess the silencing efficiency and expression of related gene bcl-2. The results revealed that BAG-1 expression was low in the adjacent normal esophageal tissues while expression was high in the esophageal carcinoma tissues. After Eca109 cells were transfected with BAG-1-siRNA, the proliferation and invasive capabilities of the cells were significantly decreased while the apoptosis rate was greatly enhanced (P<0.01). When the expression of BAG-1 in the Eca109 cells was downregulated, the expression of bcl-2 was significantly abated (P<0.05). In conclusion, BAG-1 is closely connected with the pathogenesis and development of esophageal carcinoma, which may act through affecting bcl-2.
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Affiliation(s)
- Bo Huang
- Department of Thoracic Surgery, The First Affiliated Hospital of Liaoning Medical University, Jinzhou, Liaoning 121000, P.R. China
| | - Hongli Zhou
- Department of Thoracic Surgery, The First Affiliated Hospital of Liaoning Medical University, Jinzhou, Liaoning 121000, P.R. China
| | - Xianping Lang
- Department of Thoracic Surgery, The First Affiliated Hospital of Liaoning Medical University, Jinzhou, Liaoning 121000, P.R. China
| | - Zhiliang Liu
- Department of Thoracic Surgery, The First Affiliated Hospital of Liaoning Medical University, Jinzhou, Liaoning 121000, P.R. China
| | - Fei Xiong
- Department of Thoracic Surgery, The First Affiliated Hospital of Liaoning Medical University, Jinzhou, Liaoning 121000, P.R. China
| | - Siwang Wang
- Department of Thoracic Surgery, The First Affiliated Hospital of Liaoning Medical University, Jinzhou, Liaoning 121000, P.R. China
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Gramatzki D, Herrmann C, Happold C, Becker KA, Gulbins E, Weller M, Tabatabai G. Glioma cell death induced by irradiation or alkylating agent chemotherapy is independent of the intrinsic ceramide pathway. PLoS One 2013; 8:e63527. [PMID: 23667632 PMCID: PMC3646759 DOI: 10.1371/journal.pone.0063527] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Accepted: 04/07/2013] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND/AIMS Resistance to genotoxic therapy is a characteristic feature of glioma cells. Acid sphingomyelinase (ASM) hydrolyzes sphingomyelin to ceramide and glucosylceramide synthase (GCS) catalyzes ceramide metabolism. Increased ceramide levels have been suggested to enhance chemotherapy-induced death of cancer cells. METHODS Microarray and clinical data for ASM and GCS in astrocytomas WHO grade II-IV were acquired from the Rembrandt database. Moreover, the glioblastoma database of the Cancer Genome Atlas network (TCGA) was used for survival data of glioblastoma patients. For in vitro studies, increases in ceramide levels were achieved either by ASM overexpression or by the GCS inhibitor DL-threo-1-phenyl-2-palmitoylamino-3-morpholino-1-propanol (PPMP) in human glioma cell lines. Combinations of alkylating chemotherapy or irradiation and ASM overexpression, PPMP or exogenous ceramide were applied in parental cells. The anti-glioma effects were investigated by assessing proliferation, metabolic activity, viability and clonogenicity. Finally, viability and clonogenicity were assessed in temozolomide (TMZ)-resistant cells upon treatment with PPMP, exogenous ceramide, alkylating chemotherapy, irradiation or their combinations. RESULTS Interrogations from the Rembrandt and TCGA database showed a better survival of glioblastoma patients with low expression of ASM or GCS. ASM overexpression or PPMP treatment alone led to ceramide accumulation but did not enhance the anti-glioma activity of alkylating chemotherapy or irradiation. PPMP or exogenous ceramide induced acute cytotoxicity in glioblastoma cells. Combined treatments with chemotherapy or irradiation led to additive, but not synergistic effects. Finally, no synergy was found when TMZ-resistant cells were treated with exogenous ceramide or PPMP alone or in combination with TMZ or irradiation. CONCLUSION Modulation of intrinsic glioma cell ceramide levels by ASM overexpression or GCS inhibition does not enhance the anti-glioma activity of alkylating chemotherapy or irradiation.
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Affiliation(s)
- Dorothee Gramatzki
- Laboratory of Molecular Neuro-Oncology, Department of Neurology, University Hospital Zurich, Zurich, Switzerland
| | - Caroline Herrmann
- Department of Preclinical Imaging and Radiopharmacy, University Hospital Tuebingen, Tuebingen, Germany
| | - Caroline Happold
- Laboratory of Molecular Neuro-Oncology, Department of Neurology, University Hospital Zurich, Zurich, Switzerland
| | - Katrin Anne Becker
- Department of Molecular Biology, University of Duisburg-Essen, Essen, Germany
| | - Erich Gulbins
- Department of Molecular Biology, University of Duisburg-Essen, Essen, Germany
| | - Michael Weller
- Laboratory of Molecular Neuro-Oncology, Department of Neurology, University Hospital Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Ghazaleh Tabatabai
- Laboratory of Molecular Neuro-Oncology, Department of Neurology, University Hospital Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
- * E-mail:
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Happold C, Roth P, Wick W, Schmidt N, Florea AM, Silginer M, Reifenberger G, Weller M. Distinct molecular mechanisms of acquired resistance to temozolomide in glioblastoma cells. J Neurochem 2012; 122:444-55. [DOI: 10.1111/j.1471-4159.2012.07781.x] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Hinitt CA, Benn TM, Threadgold S, Wood J, Williams AC, Hague A. BAG-1L promotes keratinocyte differentiation in organotypic culture models and changes in relative BAG-1 isoform abundance may lead to defective stratification. Exp Cell Res 2011; 317:2159-70. [PMID: 21723279 DOI: 10.1016/j.yexcr.2011.06.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 05/31/2011] [Accepted: 06/16/2011] [Indexed: 01/23/2023]
Abstract
In keratinocytes the human Bag-1 gene produces three different protein isoforms from a single messenger RNA, BAG-1L, BAG-1M and BAG-1S. In this study we questioned whether BAG-1L or the shorter isoforms would promote keratinocyte differentiation in organotypic cultures of HaCaT. HaCaT parental and vector cells showed stratification, but terminal differentiation was not complete. Cultures overexpressing BAG-1L isoform-specifically were of increased thickness, demonstrated pronounced expression of basal cytokeratin 5 and β1-integrin, suprabasal involucrin, cytokeratin 1 and plasma membrane-localised filaggrin, and a marked keratinized layer of cells at the surface. We were unable to overexpress BAG-1S and BAG-1M isoform-specifically. Overexpression of BAG-1M gave rise to organotypic cultures intermediate in differentiation to controls and those overexpressing BAG-1L. Cells overexpressing BAG-1S also exhibited elevated endogenous BAG-1. These produced slow growing cultures with high levels of basal cytokeratin 5, but little involucrin or cytokeratin 1. Suprabasal β1-integrin and Ki67 positive cells indicated defective stratification. The results suggest that BAG-1L potentiates epidermal differentiation, but disruption in the relative balance of isoforms towards overexpression of BAG-1S can lead to defective tissue patterning. Hence, a delicate balance of BAG-1 isoforms may be required to regulate normal epidermal stratification and differentiation, with important implications for aberrant differentiation in cancer.
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Yoshino K, Motoyama S, Koyota S, Shibuya K, Usami S, Maruyama K, Saito H, Minamiya Y, Sugiyama T, Ogawa JI. IGFBP3 and BAG1 enhance radiation-induced apoptosis in squamous esophageal cancer cells. Biochem Biophys Res Commun 2010; 404:1070-5. [PMID: 21195059 DOI: 10.1016/j.bbrc.2010.12.115] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 12/22/2010] [Indexed: 10/18/2022]
Abstract
Identification of reliable markers of radiosensitivity and the key molecules that enhance the susceptibility of esophageal cancer cells to anticancer treatments would be highly desirable. To identify molecules that confer radiosensitivity to esophageal squamous carcinoma cells, we assessed the radiosensitivities of the TE-5, TE-9 and TE-12 cloneA1 cell lines. TE-12 cloneA1 cells showed significantly greater susceptibility to radiotherapy at 5 and 10Gy than either TE-5 or TE-9 cells. Consistent with that finding, 24h after irradiation (5Gy), TE-12 cloneA1 cells showed higher levels of caspase 3/7 activity than TE-5 or TE-9 cells. When we used DNA microarrays to compare the gene expression profiles of TE-5 and TE-12 cloneA1 cells, we found that the mRNA and protein expression of insulin-like growth factor binding protein 3 (IGFBP3) and Bcl-2-associated athanogene 1 (BAG1) was five or more times higher in TE-12 cloneA1 cells than TE-5 cells. Conversely, knocking down expression of IGFBP3 and BAG1 mRNA in TE-12 cloneA1 cells using small interfering RNA (siRNA) significantly reduced radiosensitivity. These data suggest that IGFBP3 and BAG1 may be key markers of radiosensitivity that enhance the susceptibility of squamous cell esophageal cancer to radiotherapy. IGFBP3 and BAG1 may thus be useful targets for improved and more individualized treatments for patients with esophageal squamous cell carcinoma.
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Affiliation(s)
- Kei Yoshino
- Department of Surgery, Akita University Graduate School of Medicine, Akita, Japan
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Hinitt CA, Wood J, Lee SS, Williams AC, Howarth JL, Glover CP, Uney JB, Hague A. BAG-1 enhances cell-cell adhesion, reduces proliferation and induces chaperone-independent suppression of hepatocyte growth factor-induced epidermal keratinocyte migration. Exp Cell Res 2010; 316:2042-60. [PMID: 20430025 DOI: 10.1016/j.yexcr.2010.04.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Revised: 03/31/2010] [Accepted: 04/19/2010] [Indexed: 11/20/2022]
Abstract
Cell motility is important in maintaining tissue homeostasis, facilitating epithelial wound repair and in tumour formation and progression. The aim of this study was to determine whether BAG-1 isoforms regulate epidermal cell migration in in vitro models of wound healing. In the human epidermal cell line HaCaT, endogenous BAG-1 is primarily nuclear and increases with confluence. Both transient and stable p36-Bag-1 overexpression resulted in increased cellular cohesion. Stable transfection of either of the three human BAG-1 isoforms p36-Bag-1 (BAG-1S), p46-Bag-1 (BAG-1M) and p50-Bag-1 (BAG-1L) inhibited growth and wound closure in serum-containing medium. However, in response to hepatocyte growth factor (HGF) in serum-free medium, BAG-1S/M reduced communal motility and colony scattering, but BAG-1L did not. In the presence of HGF, p36-Bag-1 transfectants retained proliferative response to HGF with no change in ERK1/2 activation. However, the cells retained E-cadherin localisation at cell-cell junctions and exhibited pronounced cortical actin. Point mutations in the BAG domain showed that BAG-1 inhibition of motility is independent of its function as a chaperone regulator. These findings are the first to suggest that BAG-1 plays a role in regulating cell-cell adhesion and suggest an important function in epidermal cohesion.
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Chamberlain WA, Prayson RA. Focal Cortical Dysplasia Type II (Malformations of Cortical Development) Aberrantly Expresses Apoptotic Proteins. Appl Immunohistochem Mol Morphol 2008; 16:471-6. [DOI: 10.1097/pai.0b013e31815d9ac7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Abstract
Bag-1 is an anti-apoptotic protein that exhibits altered expression in many malignancies, including oral squamous cell carcinoma. The bag-1 gene gives rise to different protein products with different subcellular localisations through alternative translational initiation sites. In oral squamous cell carcinoma, cytoplasmic expression has been associated with metastasis to regional lymph nodes and poor prognosis. In contrast, the longest Bag-1 isoform is nuclear and may regulate differentiation in oral epithelium. In this review, the functions of the three isoforms of Bag-1 expressed in oral epithelial cells are discussed in relation to their contribution to oral carcinogenesis.
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Affiliation(s)
- Jemma Wood
- Department of Oral and Dental Science, University of Bristol, Lower Maudlin Street, Bristol, BS1 2LY, UK
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Abstract
BACKGROUND Differences in tumor behavior, ranging from indolent to aggressive, create a need for novel prognostic biomarkers. BAG-1 is a co-chaperone that regulates the activity of Hsp70, Bcl-2, Raf-1, growth factor, and steroid receptors (e.g., the Androgen Receptor). METHODS Using immunohistochemical method, we explored BAG-1 expression in prostate cancers and its association with clinicopathological parameters. RESULTS BAG-1 immunostaining was elevated in prostate cancer compared to normal prostatic epithelium. Higher nuclear BAG-1 in hormone-refractory (n = 34) compared to localized untreated tumors (n = 58) (P < 0.0001) suggested that upregulation of the nuclear isoform may contribute to disease progression. In 64 early-stage patients (T2N0M0) treated with external-beam irradiation, cytosolic BAG-1 correlated with higher pretreatment levels of serum Prostate specific antigen (P = 0.04) and shorter time to disease progression (P = 0.00004). CONCLUSIONS Increased cytosolic and nuclear BAG-1 expression may denote more aggressive variants of prostate cancer.
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Affiliation(s)
- Maryla Krajewska
- Burnham Institute for Medical Research, La Jolla, California, USA
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Batistatou A, Kyzas PA, Goussia A, Arkoumani E, Voulgaris S, Polyzoidis K, Agnantis NJ, Stefanou D. Estrogen receptor beta (ERbeta) protein expression correlates with BAG-1 and prognosis in brain glial tumours. J Neurooncol 2005; 77:17-23. [PMID: 16292491 DOI: 10.1007/s11060-005-9005-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2005] [Indexed: 02/06/2023]
Abstract
Estrogen receptor beta (ERbeta) is an important mediator of estrogen function in a variety of tissues. Its expression declines in breast, ovarian, prostatic and colon carcinomas as well as in astrocytic tumours. BAG-1 is a multifunctional protein with an important role in neoplasia and is possibly regulated by estrogen receptors. One of the direct targets of BAG-1 is HSP70. The purpose of this study was to analyse the expression pattern of these proteins in two distinct types of glial neoplasms, to investigate their possible correlation and probe their impact on prognosis. ERbeta, BAG-1 and HSP70 protein expression was monitored immunohistochemically in 66 cases of astrocytomas and 20 oligodendrogliomas. In astrocytic tumours low ERbeta expression correlated significantly with high grade (P < 0.001), higher expression of cytoplasmic BAG-1 (P < 0.001) and worse survival (log rank P = 0.02). Multivariate analysis revealed that ERbeta expression had a prognostic value for overall survival in these patients (Cox P = 0.03), which was not dependent on grade. There was also statistically significant association of BAG-1 nuclear expression with HSP70 cytoplasmic expression. Our results strengthen the hypothesis that ERbeta, BAG-1 and HSP70 play an important role in the pathogenesis and progression of glial neoplasms. Moreover, ERbeta expression in astrocytic tumors might be an important prognostic factor for survival.
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Affiliation(s)
- Anna Batistatou
- Department of Pathology, University of Ioannina, Medical School, 451 10, Ioannina, Greece.
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Liman J, Ganesan S, Dohm CP, Krajewski S, Reed JC, Bähr M, Wouters FS, Kermer P. Interaction of BAG1 and Hsp70 mediates neuroprotectivity and increases chaperone activity. Mol Cell Biol 2005; 25:3715-25. [PMID: 15831476 PMCID: PMC1084317 DOI: 10.1128/mcb.25.9.3715-3725.2005] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [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: 11/20/2022] Open
Abstract
It was recently shown that Bcl-2-associated athanogene 1 (BAG1) is a potent neuroprotectant as well as a marker of neuronal differentiation. Since there appears to exist an equilibrium within the cell between BAG1 binding to heat shock protein 70 (Hsp70) and BAG1 binding to Raf-1 kinase, we hypothesized that changing BAG1 binding characteristics might significantly alter BAG1 function. To this end, we compared rat CSM14.1 cells and human SHSY-5Y cells stably overexpressing full-length BAG1 or a deletion mutant (BAGDeltaC) no longer capable of binding to Hsp70. Using a novel yellow fluorescent protein-based foldase biosensor, we demonstrated an upregulation of chaperone in situ activity in cells overexpressing full-length BAG1 but not in cells overexpressing BAGDeltaC compared to wild-type cells. Interestingly, in contrast to the nuclear and cytosolic localizations of full-length BAG1, BAGDeltaC was expressed exclusively in the cytosol. Furthermore, cells expressing BAGDeltaC were no longer protected against cell death. However, they still showed accelerated neuronal differentiation. Together, these results suggest that BAG1-induced activation of Hsp70 is important for neuroprotectivity, while BAG1-dependent modulation of neuronal differentiation in vitro is not.
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Affiliation(s)
- Jan Liman
- Neurologische Klinik, Universität Göttingen, Cell Biophysics Group, European Neuroscience Institute Göttingen, Göttingen, Germany, The Burnham Institute, La Jolla, California
| | - Sundar Ganesan
- Neurologische Klinik, Universität Göttingen, Cell Biophysics Group, European Neuroscience Institute Göttingen, Göttingen, Germany, The Burnham Institute, La Jolla, California
| | - Christoph P. Dohm
- Neurologische Klinik, Universität Göttingen, Cell Biophysics Group, European Neuroscience Institute Göttingen, Göttingen, Germany, The Burnham Institute, La Jolla, California
| | - Stan Krajewski
- Neurologische Klinik, Universität Göttingen, Cell Biophysics Group, European Neuroscience Institute Göttingen, Göttingen, Germany, The Burnham Institute, La Jolla, California
| | - John C. Reed
- Neurologische Klinik, Universität Göttingen, Cell Biophysics Group, European Neuroscience Institute Göttingen, Göttingen, Germany, The Burnham Institute, La Jolla, California
| | - Mathias Bähr
- Neurologische Klinik, Universität Göttingen, Cell Biophysics Group, European Neuroscience Institute Göttingen, Göttingen, Germany, The Burnham Institute, La Jolla, California
| | - Fred S. Wouters
- Neurologische Klinik, Universität Göttingen, Cell Biophysics Group, European Neuroscience Institute Göttingen, Göttingen, Germany, The Burnham Institute, La Jolla, California
- Corresponding author. Mailing address for Fred S. Wouters: Cell Biophysics Group, European Neuroscience Institute Göttingen, Waldweg 33, 37075 Göttingen, Germany. Phone: 0049-551-3912368. Fax: 0049-551-3912346. E-mail:
| | - Pawel Kermer
- Neurologische Klinik, Universität Göttingen, Cell Biophysics Group, European Neuroscience Institute Göttingen, Göttingen, Germany, The Burnham Institute, La Jolla, California
- Corresponding author. Mailing address for Pawel Kermer: Neurologische Klinik, Universität Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany. Phone: 49-551-394927. Fax: 49-551-3914302. E-mail:
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16
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Townsend PA, Stephanou A, Packham G, Latchman DS. BAG-1: a multi-functional pro-survival molecule. Int J Biochem Cell Biol 2005; 37:251-9. [PMID: 15474970 DOI: 10.1016/j.biocel.2004.03.016] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [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: 01/15/2004] [Revised: 03/22/2004] [Accepted: 03/23/2004] [Indexed: 01/18/2023]
Abstract
BAG-1 is a multi-functional protein that exists as three functionally distinct and differentially localized isoforms which originate from a single mRNA and interact with a wide range of cellular targets. These include heat shock proteins, nuclear hormone receptors, signalling molecules, the anti-apoptotic BCL-2 protein and components of the ubiquitylation/proteasome machinery. Overexpression of BAG-1 isoforms has been demonstrated to regulate apoptosis, proliferation, transcription, metastasis and cell motility in a wide variety of cell systems. Since BAG-1 has a role in many biological pathways there is increasing evidence supporting the view that BAG-1 is an important molecule in disease, for example, potentially modulating both cell survival and response to nuclear hormones in breast cancer, and BAG-1 is a potential molecular target for therapeutic intervention.
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Affiliation(s)
- Paul A Townsend
- Medical Molecular Biology Unit, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK.
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17
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Noguchi T, Takeno S, Shibata T, Fumoto S, Uchida Y, Yokoyama S, Gabbert HE, Müller W. Nuclear BAG-1 expression is a biomarker of poor prognosis in esophageal squamous cell carcinoma. Dis Esophagus 2003; 16:107-11. [PMID: 12823208 DOI: 10.1046/j.1442-2050.2003.00307.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Apoptosis is one of the critical biological factors that correlate with the biological behavior of malignant tumors including cancer progression and clinical outcome. The present study was performed to clarify the clinical implications of BAG-1, a bcl-2 binding protein in esophageal squamous cell carcinoma (ESCC). Seventy-one cases with ESCC were investigated. Immunohistochemical study of BAG-1 was performed on resected specimens. The expression pattern of BAG-1 in nuclei and/or cytoplasm was analyzed and correlated with TNM classification, vessel invasion, survival period after surgery. BAG-1 expression in the nuclei was related to the depth of tumor invasion (P = 0.0381) but not to any other clinicopathologic parameters. The cytoplasmic staining pattern of BAG-1 exhibited no correlation with clinicopathologic parameters. Univariate analysis (P < 0.05), but not multivariate analysis, revealed significantly poor prognosis for ESCC cases exhibiting positive nucleic staining for BAG-1. Our data suggests that BAG-1 expression in the nuclei of ESCC plays an important role in tumor development and may be useful for predicting the prognosis after surgery.
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Affiliation(s)
- T Noguchi
- Department of Oncological Science (Surgery II), Oita Medical University, Oita, Japan
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18
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Abstract
BAG-1 is multifunctional protein which interacts with a wide range of cellular targets to regulate growth control pathways important for normal and malignant cells, including apoptosis, signaling, proliferation, transcription and cell motility. Of particular relevance to tumour cells, BAG-1 interacts with the anti-apoptotic BCL-2 protein, various nuclear hormone receptors and the 70 kDa heat shock proteins, Hsc70 and Hsp70. Interaction with chaperones may account for many of the pleiotropic effects associated with BAG-1 overexpression. Recent studies have shown that BAG-1 expression is frequently altered in malignant cells, and BAG-1 expression may have clinical value as a prognostic/predictive marker. This review summarises current understanding of molecular mechanisms of BAG-1 expression and function.
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Affiliation(s)
- Paul A Townsend
- Cancer Research UK Oncology Unit, Cancer Sciences Division, School of Medicine, University of Southampton, Southampton SO16 6YD, UK
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19
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Takahashi N, Yanagihara M, Ogawa Y, Yamanoha B, Andoh T. Down-regulation of Bcl-2-interacting protein BAG-1 confers resistance to anti-cancer drugs. Biochem Biophys Res Commun 2003; 301:798-803. [PMID: 12565851 DOI: 10.1016/s0006-291x(03)00020-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
BAG-1 was originally identified as a binding partner of anti-apoptotic factor Bcl-2 [Takayama et al., Cell 80 (1995) 279-284]. Exogenous expression of BAG-1 was reported to confer cells resistance to several stresses [Chen et al., Oncogene 21 (2002) 7050]. We have obtained human cervical cancer HeLa cells with down-regulated BAG-1 levels by using a highly specific and efficient RNA interference approach. Surprisingly, cells with down-regulated BAG-1 exhibited significantly lower sensitivity against several anti-cancer drugs than parental cells expressing normal levels of the protein. Furthermore, growth rate of the cells was reduced when BAG-1 was down-regulated. Activity of ERK pathway appeared to be decreased in BAG-1 down-regulated cells, as shown by the reduced phosphorylation of ERK1/2 proteins. Taken together resistance against anti-cancer drugs acquired by BAG-1 down-regulated cells may well be accounted for by the retardation of cell cycle progression, implicating the importance of BAG-1 in cell growth regulation.
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Affiliation(s)
- Noriko Takahashi
- Department of Bioengineering, Faculty of Engineering, Soka University, Hachioji, Tokyo, Japan
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20
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Abstract
Macrophages play an important role in the regulation of malignant tumors. Although glioma contains abundance of macrophages, their role in apoptosis of glioma is not known. We stimulated macrophages with lipopolysaccharide and culture supernatants of activated macrophages were collected to treat glioma cells. The results showed that molecules released from activated macrophages significantly increased apoptosis of glioma via Fas/FasL and caspase-3 pathways. The level of soluble Fas did not appear to be involved in the mechanism responsible for apoptosis seen in this study, as its level was barely detected in both experimental and control groups. Two cytokines, TNFalpha and IFNgamma, were significantly elevated in the supernatant obtained from the activated macrophages. Considering an important role of these two molecules in the induction of apoptosis mediated by the Fas/FasL system, the present data suggested that TNFalpha and IFNgamma were the main molecules to trigger the cascade of apoptotic reactions in glioma cells. In conclusion, the present study indicates that molecules released from the activated macrophages provide significant signals to stimulate the expression of Fas/FasL and caspase-3, which function to induce apoptosis in glioma cells.
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Affiliation(s)
- George G Chen
- Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin.
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21
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Hague A, Packham G, Huntley S, Shefford K, Eveson JW. Deregulated Bag-1 protein expression in human oral squamous cell carcinomas and lymph node metastases. J Pathol 2002; 197:60-71. [PMID: 12081206 DOI: 10.1002/path.1076] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Bag-1 is an anti-apoptotic protein that promotes metastasis in some tumour cell types. To determine whether Bag-1 expression is altered in 64 oral squamous cell carcinomas, tumour samples were compared with 17 samples of normal oral epithelium. Normal oral epithelia had pronounced nuclear staining in the basal and maturation layers and weak cytoplasmic staining that was most pronounced in the basal and suprabasal layers. Oral squamous cell carcinomas demonstrated a tendency for reduced nuclear staining intensity (p=0.036). Cytoplasmic staining intensity was not significantly different between tumour and normal tissue. However, many tumours were observed to have less of a difference between nuclear staining intensity and cytoplasmic staining intensity than normal oral epithelium. Furthermore, in lymph node metastases, cytoplasmic Bag-1 staining was stronger in 8/13 cases than in corresponding primary tumours (p=0.021). Western blotting using nine oral primary carcinoma cell lines and four normal keratinocyte cultures showed that the isoforms Bag-1s, Bag-1M, and Bag-1L were expressed in normal and malignant oral epithelial cells. Bag-1L unique sequences were shown to adopt an exclusively nuclear, and predominantly nucleolar, localization by use of transiently transfected N-terminal Bag-1L-EGFP. However, levels of Bag-1L in carcinoma cells did not differ significantly from those of normal keratinocytes. Therefore the reduced nuclear staining observed in oral squamous cell carcinomas compared with normal epithelium may reflect changes in the localization of Bag-1 isoforms, rather than decreased expression of Bag-1L. Alterations in the relative proportions of Bag-1S, Bag-1M, and Bag-1L were detected in 6/9 oral carcinoma cell lines; 5/9 oral carcinoma cell lines had a significantly greater proportion of Bag-1M than normal keratinocytes and in another cell line, Bag-1L was significantly underrepresented. Overall, the results suggest that Bag-1 deregulation plays a role in oral carcinogenesis at two different stages: during primary carcinoma development and during lymph node metastasis.
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Affiliation(s)
- Angela Hague
- Department of Oral and Dental Science, University of Bristol, Bristol Dental Hospital and School, UK.
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22
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Kermer P, Krajewska M, Zapata JM, Takayama S, Mai J, Krajewski S, Reed JC. Bag1 is a regulator and marker of neuronal differentiation. Cell Death Differ 2002; 9:405-13. [PMID: 11965493 DOI: 10.1038/sj.cdd.4400972] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [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: 06/10/2001] [Accepted: 10/10/2001] [Indexed: 11/08/2022] Open
Abstract
Bag 1 acts as a co-chaperone for Hsp70/Hsc70. We report here that stable over-expression of Bag1 in immortalized neuronal CSM14.1 cells prevents death following serum deprivation. Bag1 over-expression slowed the proliferative rate of CSM14.1 cells, resulted in increased levels of phospo-MAP kinases and accelerated neuronal differentiation. Immunocytochemistry revealed mostly nuclear localization of Bag1 protein in these cells. However, during differentiation in vitro, Bag1 protein shifted from predominantly nuclear to mostly cytosolic in CSM14.1 cells. To explore in vivo parallels of these findings, we investigated Bag1 expression in the developing mouse nervous system using immunohistochemical methods. Early in brain development, Bag1 was found in nuclei of neuronal precursor cells, whereas cytosolic Bag1 staining was observed mainly after completion of neuronal precursor migration and differentiation. Taken together, these findings raise the possibility that the Bag1 protein is expressed early in neurogenesis in vivo and is capable of modulating neuronal cell survival and differentiation at least in part from a nuclear location.
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Affiliation(s)
- P Kermer
- The Burnham Institute, Program on Apoptosis and Cell Death Research, 10901 N. Torrey Pines Road, La Jolla, California, CA 92037, USA
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23
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Del Bufalo D, Trisciuoglio D, Biroccio A, Marcocci L, Buglioni S, Candiloro A, Scarsella M, Leonetti C, Zupi G. Bcl-2 overexpression decreases BCNU sensitivity of a human glioblastoma line through enhancement of catalase activity. J Cell Biochem 2001; 83:473-83. [PMID: 11596115 DOI: 10.1002/jcb.1245] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The aim of this study was to evaluate the role of bcl-2 in 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) sensitivity of the ADFS human glioblastoma cell line in vitro and in vivo. To this end, the ADFS line expressing a low level of the bcl-2 protein was transfected with a bcl-2 expression vector. We found that bcl-2 overexpressing clones were less sensitive to in vitro BCNU treatment than the control clone. Cell cycle analysis demonstrated that while BCNU induced a consistent block in S/G2-M phases of the cell cycle in the control clone, it did not affect the cell cycle phase distribution of the two bcl-2 transfectants. The different sensitivity to BCNU was unrelated to the ability of bcl-2 to inhibit apoptosis, while bcl-2 appeared to protect bcl-2 transfectants from BCNU toxicity through an increase of catalase activity. The ability of the catalase inhibitor, sodium azide, to increase the BCNU sensitivity of the bcl-2 transfectants to levels of the BCNU-treated control clone substantiated the role of the catalase activity. The effect of bcl-2 in reducing sensitivity to BCNU was also confirmed by in vivo experiments. Xenografts of bcl-2 overexpressing tumors were less sensitive to BCNU treatment than xenografts originating from control cells.
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Affiliation(s)
- D Del Bufalo
- Experimental Chemotherapy Laboratory, Regina Elena Cancer Institute, Experimental Research Center, Rome, Italy.
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24
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Abstract
In order to elucidate the reason for conflicting results that have been published previously on galectin-3 expression in human gliomas, we used single labeling and double labeling immunohistochemistry experiments to identify cellular origin and extent of galectin-3 positivity in 53 glioma-samples (16 glioblastomas, 21 anaplastic astrocytomas, 16 low-grade astrocytomas). Galectin-3 positivity was observed in neoplastic astrocytes, macrophages/microglial cells. endothelial cells and some B- and T-lymphocytes. The quantitative analysis showed that the percentage of galectin-3 positive cells was significantly higher in the tumor parenchyma of glioblastomas than in anaplastic (p = 0.0371) and low-grade astrocytomas (p = 0.0042). Single labeling with anti-CD68 antibodies revealed a significant correlation between CD68 and galectin-3 immunoreactivity (p = 0.0092). Endothelial cells were labeled in all low-grade and anaplastic astrocytomas, but only in 10/16 glioblastomas (p = 0.0003). This detailed analysis demonstrates that galectin-3 positivity in human gliomas is considerably influenced by tumor-infiltrating macrophages. The differential expression on endothelial cells raises the question if galectin-3 plays a role in tumor angiogenesis of human gliomas.
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Affiliation(s)
- H M Strik
- Institute of Brain Research, Medical School, University of Tübingen, Germany.
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25
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Roth W, Wagenknecht B, Klumpp A, Naumann U, Hahne M, Tschopp J, Weller M. APRIL, a new member of the tumor necrosis factor family, modulates death ligand-induced apoptosis. Cell Death Differ 2001; 8:403-10. [PMID: 11550092 DOI: 10.1038/sj.cdd.4400827] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2000] [Revised: 11/20/2000] [Accepted: 12/07/2000] [Indexed: 01/15/2023] Open
Abstract
APRIL (a proliferation-inducing ligand) is a newly identified member of the tumor necrosis factor (TNF) family. Tumor growth-promoting as well as apoptosis-inducing effects of APRIL have been described. Here, we report that five of 12 human malignant glioma cell lines express APRIL. APRIL gene transfer experiments revealed that malignant glioma cells are refractory to growth-promoting activity of APRIL in vitro and in vivo. Interestingly, ectopic expression of APRIL confers minor protection from apoptotic cell death induced by the death ligands, CD95 ligand (CD95L) and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)/Apo2 ligand (Apo2L). This antiapoptotic activity is specific for death ligand/receptor-mediated apoptosis since APRIL does not protect glioma cells from the cytotoxicity of the drugs, teniposide, vincristine, lomustine or cisplatin. Ectopic expression of APRIL is associated with the upregulation of X-linked inhibitor of apoptosis protein (XIAP), providing a possible explanation for the antiapoptotic activity observed here. In contrast, APRIL does not regulate the expression levels of the antiapoptotic proteins FLICE-inhibitory protein (FLIP), Bcl-2 or Bcl-X(L). These findings suggest that APRIL is involved in the regulation of death ligand-induced apoptotic signaling in malignant glioma cells.
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Affiliation(s)
- W Roth
- Laboratory of Molecular Neuro-Oncology, Department of Neurology, University of Tübingen, Tübingen, Germany
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26
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Roth W, Wild-Bode C, Platten M, Grimmel C, Melkonyan HS, Dichgans J, Weller M. Secreted Frizzled-related proteins inhibit motility and promote growth of human malignant glioma cells. Oncogene 2000; 19:4210-20. [PMID: 10980594 DOI: 10.1038/sj.onc.1203783] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cellular resistance to multiple proapoptotic stimuli and invasion of surrounding brain tissue by migrating tumor cells are main obstacles to an effective therapy for human malignant glioma. Here, we report that the Wnt family of embryonic differentiation genes modulate growth of malignant glioma cells in vitro and in vivo and inhibit cellular migration in vitro. sFRPs (soluble Frizzled-related proteins) are soluble proteins that bind to Wnt and interfere with Wnt signaling. We find that sFRP-1 and sFRP-2 are produced by the majority of longterm and ex vivo malignant glioma cell lines. Glioma cells that ectopically express sFRPs exhibit increased clonogenicity and enhanced resistance to serum starvation. In contrast, sFRPs do not modulate glioma cell susceptibility to apoptosis induced by the cytotoxic cytokines, CD95 (Fas/APO-1) ligand (CD95L) or Apo2 ligand/tumor necrosis factor-related apoptosis-inducing ligand (Apo2L/TRAIL), or various cytotoxic drugs. sFRP-2 strongly promotes the growth of intracranial glioma xenografts in nude mice. In contrast, enhanced expression of sFRPs inhibits the motility of glioma cells in vitro. sFRP-mediated effects on glioma cells are accompanied by decreased expression and activity of matrix metalloproteinase-2 (MMP-2) and decreased tyrosine phosphorylation of beta-catenin. Thus, sFRPs promote survival under non-supportive conditions and inhibit the migration of glioma cells. We suggest that the regulation of these cellular processes involves expression of MMP-2 and tyrosine phosphorylation of beta-catenin. These data support a function for Wnt signaling and its modulation by sFRPs in the biology of human gliomas. Oncogene (2000) 19, 4210 - 4220
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Affiliation(s)
- W Roth
- Laboratory of Molecular Neuro-Oncology, Department of Neurology, University of Tübingen, School of Medicine, Hoppe-Seyler-Strasse 3, 72076 Tübingen, Germany
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