scholarly journals Predominant binding of Theiler's viruses to a 34-kilodalton receptor protein on susceptible cell lines.

1991 ◽  
Vol 65 (10) ◽  
pp. 5244-5249 ◽  
Author(s):  
D R Kilpatrick ◽  
H L Lipton
Keyword(s):  
Cell Lines ◽  
Receptor Protein ◽  
Susceptible Cell ◽  
Theiler's Viruses

scholarly journals Expression Changes and Impact of the Extracellular Matrix on Etoposide Resistant Human Retinoblastoma Cell Lines

2020 ◽  
Vol 21 (12) ◽  
pp. 4322 ◽  
Author(s):  
Jacqueline Reinhard ◽  
Natalie Wagner ◽  
Miriam M. Krämer ◽  
Marvin Jarocki ◽  
Stephanie C. Joachim ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Mrna Expression ◽  
Cell Lines ◽  
Cluster Formation ◽  
Collagen Iv ◽  
Tissue Inhibitor Of Metalloproteinase ◽  
Receptor Protein ◽  
Tenascin C ◽  
Chemotherapy Drugs ◽  
Protein Levels

Retinoblastoma (RB) represents the most common malignant childhood eye tumor worldwide. Several studies indicate that the extracellular matrix (ECM) plays a crucial role in tumor growth and metastasis. Moreover, recent studies indicate that the ECM composition might influence the development of resistance to chemotherapy drugs. The objective of this study was to evaluate possible expression differences in the ECM compartment of the parental human cell lines WERI-RB1 (retinoblastoma 1) and Y79 and their Etoposide resistant subclones via polymerase chain reaction (PCR). Western blot analyses were performed to analyze protein levels. To explore the influence of ECM molecules on RB cell proliferation, death, and cluster formation, WERI-RB1 and resistant WERI-ETOR cells were cultivated on Fibronectin, Laminin, Tenascin-C, and Collagen IV and analyzed via time-lapse video microscopy as well as immunocytochemistry. We revealed a significantly reduced mRNA expression of the proteoglycans Brevican, Neurocan, and Versican in resistant WERI-ETOR compared to sensitive WERI-RB1 cells. Also, for the glycoproteins α1-Laminin, Fibronectin, Tenascin-C, and Tenascin-R as well as Collagen IV, reduced expression levels were observed in WERI-ETOR. Furthermore, a downregulation was detected for the matrix metalloproteinases MMP2, MMP7, MMP9, the tissue-inhibitor of metalloproteinase TIMP2, the Integrin receptor subunits ITGA4, ITGA5 and ITGB1, and all receptor protein tyrosine phosphatase β/ζ isoforms. Downregulation of Brevican, Collagen IV, Tenascin-R, MMP2, TIMP2, and ITGA5 was also verified in Etoposide resistant Y79 cells compared to sensitive ones. Protein levels of Tenascin-C and MMP-2 were comparable in both WERI cell lines. Interestingly, Fibronectin displayed an apoptosis-inducing effect on WERI-RB1 cells, whereas an anti-apoptotic influence was observed for Tenascin-C. Conversely, proliferation of WERI-ETOR cells was enhanced on Tenascin-C, while an anti-proliferative effect was observed on Fibronectin. In WERI-ETOR, cluster formation was decreased on the substrates Collagen IV, Fibronectin, and Tenascin-C. Collectively, we noted a different ECM mRNA expression and behavior of Etoposide resistant compared to sensitive RB cells. These findings may indicate a key role of ECM components in chemotherapy resistance formation of RB.

Identification of the soluble granulocyte-macrophage colony stimulating factor receptor protein in vivo

Blood ◽  
2000 ◽  
Vol 95 (2) ◽  
pp. 461-469 ◽  
Author(s):  
Farzana Sayani ◽  
Felix A. Montero-Julian ◽  
Valerie Ranchin ◽  
Jay M. Prevost ◽  
Sophie Flavetta ◽  
...  
Keyword(s):  
Cell Lines ◽  
State Level ◽  
Leukemic Cell ◽  
Protein Product ◽  
Receptor Protein ◽  
Soluble Form ◽  
Human Neutrophils ◽  
Gm Csf ◽  
Leukemic Cell Lines

On the basis of the finding of alternatively spliced mRNAs, the -subunit of the receptor for GM-CSF is thought to exist in both a membrane spanning (tmGMR) and a soluble form (solGMR). However, only limited data has been available to support that the solGMR protein product exists in vivo. We hypothesized that hematopoietic cells bearing tmGMR would have the potential to also produce solGMR. To test this hypothesis we examined media conditioned by candidate cells using functional, biochemical, and immunologic means. Three human leukemic cell lines that express tmGMR (HL60, U937, THP1) were shown to secrete GM-CSF binding activity and a solGMR-specific band by Western blot, whereas a tmGMR-negative cell line (K562) did not. By the same analyses, leukapheresis products collected for autologous and allogeneic stem cell transplants and media conditioned by freshly isolated human neutrophils also contained solGMR. The solGMR protein in vivo displayed the same dissociation constant (Kd = 2-5 nmol) as that of recombinant solGMR. A human solGMR ELISA was developed that confirmed the presence of solGMR in supernatant conditioned by the tmGMR-positive leukemic cell lines, hematopoietic progenitor cells, and neutrophils. Furthermore, the ELISA demonstrated a steady state level of solGMR in normal human plasma (36 ± 17 pmol) and provided data suggesting that plasma solGMR levels can be elevated in acute myeloid leukemias.

1,25-Dihydroxyvitamin D3 receptor RNA: expression in hematopoietic cells

Blood ◽  
1991 ◽  
Vol 77 (6) ◽  
pp. 1238-1247 ◽  
Author(s):  
M Kizaki ◽  
AW Norman ◽  
JE Bishop ◽  
CW Lin ◽  
A Karmakar ◽  
...  
Keyword(s):  
T Lymphocytes ◽  
Cell Lines ◽  
Hematopoietic Cells ◽  
Constitutive Expression ◽  
Peripheral Blood Lymphocytes ◽  
Leukemic Cells ◽  
Receptor Protein ◽  
Dihydroxyvitamin D3 ◽  
1,25 Dihydroxyvitamin D3 ◽  
Normal Individuals

Abstract 1,25-Dihydroxyvitamin D3 [1,25(OH)2D3] induces differentiation and inhibits proliferation of myeloid leukemic cells from various lines and patients; these effects are probably mediated through the 1,25(OH)2D3 receptor. Little is known of expression of 1,25(OH)2D3 receptor RNA in hematopoietic cells. We examined the expression and modulation of expression of 1,25(OH)2D3 receptor RNA in various proliferating and nonproliferating hematopoietic cells. Constitutive expression of 1,25(OH)2D3 receptor RNA was detected in various kinds of hematopoietic cells, including macrophages and activated T lymphocytes, as well as in cell lines KG-1 (myeloblasts), HL-60 (promyelocytes), ML-3 (myelomonoblasts), U937, THP-1 (monoblasts), K562 (erythroblasts), and S-LB1 (HTLV-1-transfected T lymphocytes). Receptor transcripts were 4.6 kilobases (kb), and no variant sizes were observed. All cell lines examined in this group also expressed 1,25(OH)2D3 receptors. Most B lymphocyte lines expressed negligible levels of 1,25(OH)2D3 receptor RNA and protein; however; analysis of a lymphoid/myeloid somatic hybrid suggested that suppression of expression of 1,25(OH)2D3 receptor RNA in B lymphocytes may be a dominant characteristic. HL-60 cells were cultured with 10(-7) mol/L 1,25(OH)2D3 for 24 to 72 hours, and levels of expression of 1,25(OH)2D3 receptor and its RNA were examined. Levels of RNA coding for the receptor were not modulated by exposure to high levels of ligand. Levels of occupied 1,25(OH)2D3 receptor protein increased in these HL-60 cells; but the total number of 1,25(OH)2D3 receptors decreased about 50% at 24 hours and returned toward normal at 72 hours. Steady-state levels of 1,25(OH)2D3 receptor RNA were not affected by terminal differentiation of HL-60 toward either granulocytes or macrophages. Nondividing macrophages from normal individuals also expressed 1,25(OH)2D3 receptor RNA. In contrast, nondividing peripheral blood lymphocytes from normal individuals did not express 1,25(OH)2D3 receptor RNA; with stimulation of proliferation of these cells, accumulation of 1,25(OH)2D3 receptor RNA increased markedly. Half-life (t1/2) of 1,25(OH)2D3 receptor RNA in T lymphocytes was short (1 hour) as determined by measuring decay of the message after addition of actinomycin D. Consistent with this short t1/2, accumulation of 1,25(OH)2D3 receptor RNA increased in cells as their protein synthesis was inhibited. Further studies are required to understand the physiologic role of 1,25(OH)2D3 receptors in myeloid cells and proliferating T lymphocytes.

scholarly journals The Cell-Specific Phenotype of the Polymorphic vacA Midregion Is Independent of the Appearance of the Cell Surface Receptor Protein Tyrosine Phosphatase β

2006 ◽  
Vol 74 (1) ◽  
pp. 49-55 ◽  
Author(s):  
David A. G. Skibinski ◽  
Christophe Genisset ◽  
Silvia Barone ◽  
John L. Telford
Keyword(s):  
Cell Surface ◽  
Cell Lines ◽  
Protein Tyrosine Phosphatase ◽  
Tyrosine Phosphatase ◽  
Cell Surface Receptor ◽  
Receptor Protein ◽  
Protein Tyrosine ◽  
Amino Acid Region ◽  
Receptor Protein Tyrosine Phosphatase ◽  
Surface Receptor

ABSTRACT There are two alleles, m1 and m2, of the midregion of the vacuolating cytotoxin gene (vacA) of Helicobacter pylori which code for toxins with different cell specificities. Here we describe the construction of five chimeric strains in which regions of vacA were exchanged between the two genotypes. By analyzing the toxicity of these strains for HeLa and RK13 cells we have confirmed that a 148-amino-acid region determines the phenotypic differences between the two forms of the protein and that this entire region is important for cytotoxicity. Furthermore, we have used our chimeric strains to investigate whether variations in the midregion of VacA have an effect on phorbol 12-myristate 13-acetate (PMA)-induced VacA sensitivity in HL-60 cells. The PMA-induced VacA sensitivity of HL-60 cells has been previously associated with the appearance of the cell surface receptor protein tyrosine phosphatase beta (RPTPβ). Our data indicate that both the m1 and m2 forms of VacA are able to utilize RPTPβ, and the cell-specific phenotype of the midregion is independent of the presence of RPTPβ. It appears that another as-yet-unidentified receptor exists in HL-60 cells that accounts for the m2 phenotype in this cell line. Also, by studying the effect of PMA on levels of RPTPβ in other cell lines and toxicity of VacA in these cell lines we have shown that RPTPβ does not play a major role in the vacuolation of HeLa cells.

scholarly journals Caveolin-1 Loss of Function Accelerates Glucose Transporter 4 and Insulin Receptor Degradation in 3T3-L1 Adipocytes

Endocrinology ◽  
2009 ◽  
Vol 150 (8) ◽  
pp. 3493-3502 ◽  
Author(s):  
Elena González-Muñoz ◽  
Carmen López-Iglesias ◽  
Maria Calvo ◽  
Manuel Palacín ◽  
Antonio Zorzano ◽  
...  
Keyword(s):  
Insulin Receptor ◽  
Cell Lines ◽  
Glucose Transporter ◽  
Lentiviral Vectors ◽  
Receptor Activation ◽  
Receptor Protein ◽  
Membrane Microdomains ◽  
Glucose Transporter 4 ◽  
Loss Of Function ◽  
Caveolin 1

Caveolae are a specialized type of lipid rafts that are stabilized by oligomers of caveolin protein. Caveolae are particularly enriched in adipocytes. Here we analyzed the effects of caveolin-1 knockdown and caveolae ablation on adipocyte function. To this end, we obtained several multiclonal mouse 3T3-L1 cell lines with a reduced expression of caveolin-1 (95% reduction) by a small interfering RNA approach using lentiviral vectors. Control cell lines were obtained by lentiviral infection with lentiviral vectors encoding appropriate scrambled RNAs. Caveolin-1 knockdown adipocytes showed a drastic reduction in the number of caveolae (95% decrease) and cholera toxin labeling was reorganized in dynamic plasma membrane microdomains. Caveolin-1 depletion caused a specific decrease in glucose transporter 4 (GLUT4) and insulin receptor protein levels. This reduction was not the result of a generalized defect in adipocyte differentiation or altered gene expression but was explained by faster degradation of these proteins. Caveolin-1 knockdown adipocytes showed reductions in insulin-stimulated glucose transport, insulin-triggered GLUT4 recruitment to the cell surface, and insulin receptor activation. In all, our data indicate that caveolin-1 loss of function reduces maximal insulin response through lowered stability and diminished expression of insulin receptors and GLUT4. We propose that caveolin-1/caveolae control insulin action in adipose cells.

scholarly journals Apoptosis induced by polyclonal antilymphocyte globulins in human B- cell lines

Blood ◽  
1994 ◽  
Vol 83 (4) ◽  
pp. 1051-1059 ◽  
Author(s):  
N Bonnefoy-Berard ◽  
L Genestier ◽  
M Flacher ◽  
JP Rouault ◽  
G Lizard ◽  
...  
Keyword(s):  
B Cell ◽  
Cell Lines ◽  
Immunosuppressive Agents ◽  
Resistant Cell ◽  
Resistant Cell Line ◽  
Lymphoma Cell ◽  
Dna Breaks ◽  
Nuclear Condensation ◽  
Susceptible Cell ◽  
Barr Virus

Antilymphocyte and antithymocyte globulins (ALG) are currently used as immunosuppressive agents in clinical transplantation and for the treatment of severe aplastic anemia. ALG contain a mixture of antibodies that recognize T- and B-cell-specific antigens but mostly nonlineage-specific molecules. We reported previously that ALG could inhibit the proliferation of activated B cells and B cell lines (Bonnefoy-Berard et al, Blood 79:2164, 1992). We show here that ALG induce apoptosis of several human hematopoietic cell lines, as shown by nuclear condensation and fragmentation in fluorescence and electronic microscopy and by double-strand DNA breaks shown by DNA electrophoresis. Apoptosis was achieved without elevation of intracellular Ca2+ and requirement for mRNA and protein synthesis. Most of the B-cell lines tested (Epstein-Barr virus [EBV]-transformed lymphoblastoid cell lines, EBV-negative and groups I/III EBV-positive Burkitt's lymphoma cell lines, as well as other B-lymphoma cell lines) were susceptible to ALG-induced cytotoxicity. Myelomonocytic and T-cell lines were much less susceptible than B-cell lines. Susceptibility to ALG-induced cytotoxicity was not correlated with intracellular Bcl-2 level. Most cell lines that express high levels of Fas/Apo-1 antigen were susceptible to ALG. However, several lines of evidence support the conclusion that, in addition to Fas/Apo-1, other cell surface molecules can mediate ALG-induced apoptosis. The cytotoxic activity could be fully removed by adsorption on susceptible cell lines but not on a resistant cell line, indicating that it was mediated by antibodies specific for surface antigens expressed only on susceptible cell lines. Apoptosis was triggered by ALG F(ab')2 fragments as well as by intact ALG. This cytotoxic property of ALG may account for their antiproliferative effect and might contribute to some extent to the relatively lower risk of posttransplant lymphoproliferative disorders previously reported in ALG-treated patients.

scholarly journals Site-selective cAMP analogs at micromolar concentrations induce growth arrest and differentiation of acute promyelocytic, chronic myelocytic, and acute lymphocytic human leukemia cell lines

Blood ◽  
1988 ◽  
Vol 71 (1) ◽  
pp. 230-233 ◽  
Author(s):  
G Tortora ◽  
P Tagliaferri ◽  
T Clair ◽  
O Colamonici ◽  
LM Neckers ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Growth Inhibition ◽  
Cell Lines ◽  
Leukemia Cell ◽  
Leukemic Cells ◽  
Receptor Protein ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Transferase Activity ◽  
Human Leukemia ◽  
Monocytic Differentiation

Abstract Cyclic AMP (cAMP)-dependent protein kinase may play a role in the functional and morphological differentiation of leukemic cells. In this study, we showed that the cAMP analogs, potent activators of protein kinase recently shown to be selective for either site 1 or site 2 cAMP binding sites of protein kinase, demonstrate potent growth inhibition of acute promyelocytic, chronic myelocytic, and acute lymphocytic leukemic cell lines with no sign of toxicity. The growth inhibition accompanied monocytic differentiation in HL-60 cells and a loss of nuclear terminal deoxynucleotidyl transferase activity in Molt-4 leukemic cells. The growth inhibition also paralleled a decrease in c- myc protein and RI cAMP receptor protein. Thus, cAMP analogs selective for either site 1 or site 2 of the protein kinase appear to restore a coupling of proliferation and maturation in leukemic cells.

Genetic Analysis of a Multifocal Glioblastoma Multiforme: A Suitable Tool to Gain New Aspects in Glioma Development

Neurosurgery ◽  
2003 ◽  
Vol 53 (6) ◽  
pp. 1377-1384 ◽  
Author(s):  
Dietmar Krex ◽  
Brigitte Mohr ◽  
Hella Appelt ◽  
Hans K. Schackert ◽  
Gabriele Schackert
Keyword(s):  
Glioblastoma Multiforme ◽  
Loss Of Heterozygosity ◽  
Cell Lines ◽  
Homozygous Deletion ◽  
Receptor Protein ◽  
Pten Gene ◽  
Balanced Translocation ◽  
In Vitro Proliferation ◽  
Suitable Tool

Abstract OBJECTIVE Multifocal glioblastomas constitute an increasingly diagnosed subgroup of glioblastoma multiforme, the most malignant primary brain tumor in adults. The molecular background of these lesions is unknown. However, the ability to study multiple lesions of one patient simultaneously could provide new aspects in glioma development. METHODS Short-term cell cultures were derived from three isolated glioblastoma lesions of one patient. Spectral karyotyping and interphase fluorescence in situ hybridization were used for cytogenetic analysis. Loss of heterozygosity was assessed in tumor tissues and cell lines for seven gene loci (p73, p21, p16, PTEN, p27, Rb, p53). In addition, sequence analysis of the PTEN and p53 loci was performed, epidermal growth factor receptor protein expression was assessed, and in vitro proliferation was assayed. RESULTS A balanced translocation [t(1;15)(p3?6;q2?5)] that has not been described previously in glioblastomas was identified in all cell lines. Primarily, the cell lines have a homozygous deletion of the p16 locus and inactivation of the PTEN gene by loss of heterozygosity and an identical mutation in common. Furthermore, the cell lines harbor a hemizygous (R175H) or two heterozygous (R175H, R213Q) mutations of the p53 gene or none at all. The occurrence of p53 mutations correlates with the size of the original tumors and in vitro proliferation. CONCLUSION The analysis of a multifocal glioma revealed three main aspects: 1) the combined cytogenetic and molecular analysis of this subgroup of glioblastoma multiforme is a suitable tool to gain new perspectives in glioma development, 2) the balanced translocation [t(1;15)(p3?6;q2?5)] might harbor a new genetic marker involved in glioma development, and 3) the pattern of p53 mutation suggests a role of p53 in the progression of malignancy, migration, and growth of this particular primary glioblastoma.

scholarly journals Building the case for the calcitonin receptor as a viable target for the treatment of glioblastoma

2020 ◽  
Vol 12 ◽  
pp. 175883592097811
Author(s):  
Pragya Gupta ◽  
Sebastian G. B. Furness ◽  
Lucas Bittencourt ◽  
David L. Hare ◽  
Peter J. Wookey
Keyword(s):  
Stem Cells ◽  
Cell Lines ◽  
Splice Variants ◽  
High Grade Glioma ◽  
Receptor Protein ◽  
Calcitonin Receptor ◽  
Direct Role ◽  
Malignant Glioma Cells ◽  
Satellite Stem Cells ◽  
Quiescent Stem Cells

Researchers are actively seeking novel targeted therapies for the brain tumour glioblastoma (GBM) as the mean survival is less than 15 months. Here we discuss the proposal that the calcitonin receptor (CT Receptor), expressed in 76–86% of patient biopsies, is expressed by both malignant glioma cells and putative glioma stem cells (GSCs), and therefore represents a potential therapeutic target. Forty-two per cent (42%) of high-grade glioma (HGG; representative of GSCs) cell lines express CT Receptor protein. CT Receptors are widely expressed throughout the life cycle of organisms and in some instances promote apoptosis. Which of the common isoforms of the CT Receptor are predominantly expressed is currently unknown, but a functional response to cell stress of the insert-positive isoform is hypothesised. A model for resistant malignancies is one in which chemotherapy plays a direct role in activating quiescent stem cells for replacement of the tumour tissue hierarchy. The putative role that the CT Receptor plays in maintenance of quiescent cancer stem cells is discussed in view of the activation of the Notch–CT Receptor–collagen V axis in quiescent muscle (satellite) stem cells. The pharmacological CT response profiles of four of the HGG cell lines were reported. Both CT responders and non-responders were sensitive to an immunotoxin based on an anti-CT Receptor antibody. The CALCR mRNA exhibits alternative splicing commonly associated with cancer cells, which could result in the atypical pharmacology exhibited by CT non-responders and an explanation of tumour suppression. Due to the inherent instability of CALCR mRNA, analysis of CT Receptor protein in patient samples will lead to improved data for the expression of CT Receptor in GBM and other cancers, and an understanding of the role and activity of the splice variants. This knowledge will aid the effective targeting of this receptor for treatment of GBM.

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