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1.
Rheumatol Int ; 42(3): 485-492, 2022 03.
Article in English | MEDLINE | ID: mdl-33782747

ABSTRACT

Diffuse alveolar hemorrhage (DAH) is a rare but potentially life-threatening emergency that has both immune and non-immune etiologies. The objective of this investigation was to compare the risk factors and outcomes of immune and non-immune causes of DAH at a tertiary-care academic center. This was a retrospective observational study conducted at a University center. We reviewed all chest radiographs spanning 12 years (2007-2019) at our institute with the words "diffuse alveolar hemorrhage" in the body of their report, and ascertained cases of DAH through a detailed chart review. We used Chi-squared test to determine the differences in risk factors and outcomes between immune versus non-immune causes of DAH. We performed logistic regressions to assess whether baseline demographics and clinical features influence four critical outcomes: death, shock, renal failure, and severe anemia requiring transfusions. Over the 12-year period, there were 88 patients with DAH, 55 with non-immune and 33 with immune etiologies. Among immune causes of DAH, granulomatosis with polyangiitis (GPA) (10.2%), microscopic polyangiitis (MPA) (9%) and systemic lupus erythematosus (SLE) (9%) were most common. Among non-immune causes of DAH, coagulopathy (6.8%), decompensated heart failure (4.5%) and infection (3.4%) were most common. Patients with non-immune causes of DAH were 45.8% more likely to die and 20.7% less likely to experience sustained remission (p = 0.001). Patient with immune causes of DAH were 21% more likely to have extra-pulmonary findings and 23.7% more likely to have received hemodialysis (HD). The presence of extra-pulmonary findings was statistically significantly correlated with the number of blood products received, the need for HD and non-statistically significantly correlated with likelihood of death. Patients with immune causes of DAH were 71.5% more likely to receive multimodal therapy including corticosteroids. Immune-mediated DAH is associated with a better prognosis than non-immune DAH, despite its greater association with extra-pulmonary findings and requirement for hemodialysis.


Subject(s)
Granulomatosis with Polyangiitis/complications , Heart Failure/complications , Hemorrhage/etiology , Lupus Erythematosus, Systemic/complications , Adult , Aged , Female , Hemorrhage/diagnostic imaging , Humans , Male , Middle Aged , Retrospective Studies , Risk Factors
2.
Epidemiol Infect ; 145(9): 1898-1909, 2017 07.
Article in English | MEDLINE | ID: mdl-28367767

ABSTRACT

An outbreak of influenza A(H1N1)pdm09 was detected during the ongoing community-based surveillance of influenza-like illness (ILI). Among reported 119 influenza A(H1N1)pdm09 cases (59 cases in the year 2012 and 60 cases in 2015) in summer months, common clinical features were fever (100%), cough (90·7%), sore throat (85·7%), nasal discharge (48·7%), headache (55·5%), fatigue (18·5%), breathlessness (3·4%), and ear discharge (1·7%). Rise in ILI cases were negatively correlated with the seasonal factors such as relative humidity (Karl Pearson's correlation coefficient, i.e. r = -0·71 in the year 2012 and r = -0·44 in the year 2015), while rise in ILI cases were positively correlated with the temperature difference (r = 0·44 in the year 2012 and r = 0·77 in the year 2015). The effective reproduction number R, was estimated to be 1·30 in 2012 and 1·64 in 2015. The study highlights the rise in unusual influenza activity in summer month with high attack rate of ILI among children aged ⩽9 years. Children in this age group may need special attention for influenza vaccination. Influenza A(H1N1)pdm09 outbreak was confirmed in inter-seasonal months during the surveillance of ILI in Pune, India, 2012-2015.


Subject(s)
Climate , Disease Outbreaks , Influenza A Virus, H1N1 Subtype/physiology , Influenza, Human/epidemiology , Influenza, Human/virology , Oseltamivir/pharmacology , Adolescent , Adult , Aged , Aged, 80 and over , Antiviral Agents/pharmacology , Child , Child, Preschool , Female , Hemagglutinins, Viral/genetics , Humans , India/epidemiology , Infant , Infant, Newborn , Influenza A Virus, H1N1 Subtype/classification , Influenza A Virus, H1N1 Subtype/immunology , Male , Middle Aged , Phylogeny , RNA, Viral/analysis , Seasons , Sequence Analysis, RNA , Young Adult
4.
Nat Genet ; 22(4): 394-9, 1999 Aug.
Article in English | MEDLINE | ID: mdl-10431247

ABSTRACT

LIM domains are required for both inhibitory effects on LIM homeodomain transcription factors and synergistic transcriptional activation events. The inhibitory actions of the LIM domain can often be overcome by the LIM co-regulator known as CLIM2, LDB1 and NLI (referred to hereafter as CLIM2; refs 2-4). The association of the CLIM cofactors with LIM domains does not, however, improve the DNA-binding ability of LIM homeodomain proteins, suggesting the action of a LIM-associated inhibitor factor. Here we present evidence that LIM domains are capable of binding a novel RING-H2 zinc-finger protein, Rlim (for RING finger LIM domain-binding protein), which acts as a negative co-regulator via the recruitment of the Sin3A/histone deacetylase corepressor complex. A corepressor function of RLIM is also suggested by in vivo studies of chick wing development. Overexpression of the gene Rnf12, encoding Rlim, results in phenotypes similar to those observed after inhibition of the LIM homeodomain factor LHX2, which is required for the formation of distal structures along the proximodistal axis, or by overexpression of dominant-negative CLIM1. We conclude that Rlim is a novel corepressor that recruits histone deacetylase-containing complexes to the LIM domain.


Subject(s)
Histone Deacetylases/metabolism , Homeodomain Proteins/antagonists & inhibitors , Repressor Proteins/physiology , Transcription Factors/antagonists & inhibitors , Amino Acid Sequence , Animals , COS Cells , Chick Embryo , Extremities/anatomy & histology , Extremities/embryology , Gene Expression Regulation, Developmental , Mice , Molecular Sequence Data , Repressor Proteins/analysis , Sequence Homology, Amino Acid , Time Factors , Tissue Distribution , Transfection , Ubiquitin-Protein Ligases
5.
J Family Med Prim Care ; 10(11): 4017-4022, 2021 Nov.
Article in English | MEDLINE | ID: mdl-35136761

ABSTRACT

BACKGROUND AND AIM: To evaluate and compare the efficacy of external cold and a vibrating device in reducing the pain and anxiety amidst children receiving maxillary infiltration anaesthesia over conventional methods. METHOD: A sum of thirty subjects aged between 5 and 10 years who had undergone dental procedures requiring maxillary infiltration were enrolled in the current split-mouth randomised control study. The control intervention constitutes infiltration of 1.8 mL of 2% lignocaine in addition to 1:100,000 adrenaline (Lox, Neon Laboratories Mumbai, India) whereas, the experimental group used external cold and a vibrating device (Buzzy®, MMJ Labs, Atlanta, GA, USA) in annexation to the control protocol. Simultaneous to LA administration, pulse rate was employed as an objective measure and the subjective measure was recorded using RMS Pictorial Scale (RMS-PS) for the child's discomfort. To document the child's pain as anticipated by the dentist the revised face, limbs, arms, cry and consolability (FLACC-R) scale was employed. RESULT: Lower pain sensation and anxiety was recorded in the experimental group using Buzzy when compared to control. CONCLUSION: External cold in adjacent with vibrations might be efficient in lowering pain as well as anxiety in children experiencing infiltration dental anaesthesia though further research work is requisite with a larger sample size.

6.
Mol Cell Biol ; 14(6): 4280-5, 1994 Jun.
Article in English | MEDLINE | ID: mdl-8196664

ABSTRACT

The type II receptors for the polypeptide growth factors transforming growth factor beta (TGF-beta) and activin belong to a new family of predicted serine/threonine protein kinases. In Xenopus embryos, the biological effects of activin and TGF-beta 1 are strikingly different; activin induces a full range of mesodermal cell types in the animal cap assay, while TGF-beta 1 has no effects, presumably because of the lack of functional TGF-beta receptors. In order to assess the biological activities of exogenously added TGF-beta 1, RNA encoding the TGF-beta type II receptor was introduced into Xenopus embryos. In animal caps from these embryos, TGF-beta 1 and activin show similar potencies for induction of mesoderm-specific mRNAs, and both elicit the same types of mesodermal tissues. In addition, the response of animal caps to TGF-beta 1, as well as to activin, is blocked by a dominant inhibitory ras mutant, p21(Asn-17)Ha-ras. These results indicate that the activin and TGF-beta type II receptors can couple to similar signalling pathways and that the biological specificities of these growth factors lie in their different ligand-binding domains and in different competences of the responding cells.


Subject(s)
Embryo, Nonmammalian/physiology , Inhibins/pharmacology , Mesoderm/physiology , Receptors, Growth Factor/physiology , Receptors, Transforming Growth Factor beta/physiology , Transforming Growth Factor beta/pharmacology , Xenopus laevis/embryology , Activin Receptors , Activins , Animals , Embryo, Nonmammalian/cytology , Mesoderm/cytology , Mesoderm/drug effects , Protein Serine-Threonine Kinases/metabolism , Proto-Oncogene Proteins p21(ras)/metabolism , Receptors, Growth Factor/biosynthesis , Receptors, Transforming Growth Factor beta/biosynthesis , Signal Transduction
7.
Proc Inst Mech Eng H ; 221(2): 153-60, 2007 Feb.
Article in English | MEDLINE | ID: mdl-17385569

ABSTRACT

Surfactants influence functions of proteins in cell signalling. Because molecular mechanisms of surfactants are poorly understood, the cationic surfactant effect on three metabolically important enzymes--L-glutamate dehydrogenase, L-lactate dehydrogenase, and L-malate dehydrogenase--were investigated at a physiologically relevant pH range (6.5-7.4). How a cationic, a non-ionic, and an anionic surfactant could differentially influence these enzymes, and how these surfactants could influence the interfacial mass transport of these enzymes across a polycarbonate membrane in a separation cell were also investigated. Provided the charge density was the same, cationic surfactants affected enzymatic activities similarly, regardless of their molecular masses. Hence, a cationic surfactant behaved similarly to a hydrophilic anionic surfactant; however, the cationic surfactant also enhanced enzymatic activity at pH 6.5 and a moderately high concentration (150 ppm). The hydrophilic surfactant enhanced enzymatic activity and the hydrophobic surfactant depressed enzymatic activity. Addition of 0.1 ppm of the hydrophilic anionic surfactant decreased the amount of enzyme permeation through the membrane, but 0.1 ppm of the non-ionic surfactant had no effect, whereas 0.1 ppm of the hydrophobic surfactant increased enzyme permeation. These results have physiological and signalling implications in nanobiotechnology.


Subject(s)
Models, Chemical , Oxidoreductases/chemistry , Surface-Active Agents/chemistry , Cations , Computer Simulation , Enzyme Activation , Enzyme Stability
8.
Cancer Res ; 61(24): 8851-8, 2001 Dec 15.
Article in English | MEDLINE | ID: mdl-11751408

ABSTRACT

It has been shown that serum levels of interleukin (IL)-6 are elevated in patients with various types of cancer. However, the exact source of IL-6 in these patients and its role in tumor progression remain unclear. Here we demonstrate that the autocrine production of IL-6 by tumor cells promotes resistance of the cells to chemotherapy, a novel function of IL-6 in cancer biology. Breast cancer cells that are sensitive to drug treatment do not express IL-6, whereas high levels of IL-6 are produced by multidrug-resistant breast cancer cells. Expression of the IL-6 gene in drug-sensitive breast cancer cells increases their resistance to drug treatment by activating the CCAAT enhancer-binding protein family of transcription factors and inducing mdr1 gene expression. Thus, the autocrine production of IL-6 by tumor cells is an important factor in determining the susceptibility or resistance of these cells to drug treatment. Because tumors from some breast cancer patients contain IL-6-producing cells, it is possible that IL-6 could potentially be used as a prognostic factor for chemotherapy resistance.


Subject(s)
Breast Neoplasms/drug therapy , Breast Neoplasms/metabolism , Drug Resistance, Multiple/physiology , Interleukin-6/biosynthesis , Transcription Factors , ATP Binding Cassette Transporter, Subfamily B, Member 1/biosynthesis , ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics , Breast Neoplasms/genetics , CCAAT-Enhancer-Binding Protein-beta/biosynthesis , CCAAT-Enhancer-Binding Protein-beta/genetics , CCAAT-Enhancer-Binding Protein-delta , CCAAT-Enhancer-Binding Proteins/biosynthesis , CCAAT-Enhancer-Binding Proteins/genetics , Cell Division/physiology , Gene Expression Regulation, Neoplastic , Genes, MDR , Humans , Tumor Cells, Cultured , Up-Regulation
10.
Biochim Biophys Acta ; 1027(1): 93-101, 1990 Aug 10.
Article in English | MEDLINE | ID: mdl-2397225

ABSTRACT

Lipid-protein interactions were studied using Torpedo californica acetylcholine receptor (AChR) as a model system by reconstituting purified AChR into dielaidoylphosphatidylcholine (DEPC, 18:1 trans-9,10) membranes. The structural and thermodynamic behavior of lipids in the vicinity of the protein were studied by differential scanning calorimetry and Fourier transform infrared spectroscopy. The effects of AChR on the thermodynamic parameters associated with lipid phase transitions were to reduce the enthalpy change, lower the transition temperature and reduce the cooperative behavior of the lipid molecules. A stoichiometry of approx. 95 lipids per AChR molecule was found by simulating the decrease in enthalpy in terms of a simple model in which a fixed number of lipid molecules are prevented from undergoing a cooperative phase transition. In parallel, the vibrational spectra of pure DEPC and AChR reconstituted in DEPC membranes at various lipid to protein ratios were examined. Profiles of the 3000-2800 cm-1 C-H stretching region and 1350-950 cm-1 characteristic of the headgroup region of the lipid exhibit little sensitivity to protein/lipid ratio reflecting weak interaction of AChR with DEPC. The lipid carbonyl on the other hand appear to be increasingly hydrogen bonded in the presence of AChR. The results provide new information about the size and physical state of the motionally restricted lipid environment that surrounds the acetylcholine receptor. The results are discussed in the context of lipid-mediated alterations in acetylcholine receptor function.


Subject(s)
Membrane Lipids/physiology , Receptors, Nicotinic/physiology , Animals , Calorimetry, Differential Scanning , Cell Membrane/physiology , Cell Membrane/ultrastructure , Fourier Analysis , In Vitro Techniques , Microscopy, Electron , Spectrophotometry, Infrared , Thermodynamics , Torpedo
11.
Biochim Biophys Acta ; 963(3): 509-14, 1988 Dec 16.
Article in English | MEDLINE | ID: mdl-2973813

ABSTRACT

Acyl-CoA ligase activities, solubilized from rat brain microsomes, were fractionated into three different peaks by hydroxyapatite chromatography. Based on physical and chemical properties, we suggested that peak A (pamitoyl-CoA ligase) and peak C (lignoceroyl-CoA ligase) were two different enzymes (A. Bhushan, R. P. Singh, and I. Singh (1986) Arch. Biochem. Biophys. 246, 374-380). We raised antibodies against purified liver microsomal palmitoyl-CoA ligase (EC 6.2.1.3) and examined the effect of this antibody on acyl-CoA ligase activities for palmitic, arachidonic and lignoceric acids in microsomal enzyme extract and different acyl-CoA ligase peaks from the hydroxyapatite column. In an enzyme activity assay system in microsomal extract, the antisera inhibited the palmitoyl-CoA ligase activity but had very little effect on the acyl-CoA ligase activities for arachidonic and lignoceric acids. This antisera inhibited the acyl-CoA ligase activities for these three fatty acids in peak A and had no effect on these activities in peak B or peak C. Western blot analysis demonstrated that antibody to liver microsomal palmitoyl-CoA ligase cross-reacted with only peak A (palmitoyl-CoA ligase), but not with peak B or peak C. This immunochemical study demonstrates that palmitoyl-CoA ligase does not share immunological determinants with acyl-CoA ligases in peaks B or C, thus demonstrating that palmitoyl-CoA ligase (peak A) is different from the arachidonoyl-CoA and lignoceroyl-CoA ligase activities in peaks B or C.


Subject(s)
Brain/enzymology , Coenzyme A Ligases/metabolism , Microsomes/enzymology , Repressor Proteins , Saccharomyces cerevisiae Proteins , Animals , Arachidonic Acid , Arachidonic Acids/metabolism , Brain/ultrastructure , Cross Reactions , Fatty Acids/metabolism , Immunohistochemistry , Rats , Solubility
12.
Technology (Singap World Sci) ; 3(1): 1-26, 2015 Mar.
Article in English | MEDLINE | ID: mdl-26167518

ABSTRACT

The liver performs many key functions, the most prominent of which is serving as the metabolic hub of the body. For this reason, the liver is the focal point of many investigations aimed at understanding an organism's toxicological response to endogenous and exogenous challenges. Because so many drug failures have involved direct liver toxicity or other organ toxicity from liver generated metabolites, the pharmaceutical industry has constantly sought superior, predictive in-vitro models that can more quickly and efficiently identify problematic drug candidates before they incur major development costs, and certainly before they are released to the public. In this broad review, we present a survey and critical comparison of in-vitro liver technologies along a broad spectrum, but focus on the current renewed push to develop "organs-on-a-chip". One prominent set of conclusions from this review is that while a large body of recent work has steered the field towards an ever more comprehensive understanding of what is needed, the field remains in great need of several key advances, including establishment of standard characterization methods, enhanced technologies that mimic the in-vivo cellular environment, and better computational approaches to bridge the gap between the in-vitro and in-vivo results.

14.
Immunol Res ; 24(3): 311-24, 2001.
Article in English | MEDLINE | ID: mdl-11817328

ABSTRACT

Hyper-IgM (HIM) syndrome is a rare immunodeficiency characterized by low or absent IgG, IgA, and IgE with normal or elevated levels of IgM. This disorder can be acquired or familial with either X-linked or autosomal patterns of inheritance. The X-linked form of the disease is a consequence of mutations in the CD40 ligand (CD40L) gene that encodes a protein expressed primarily on activated CD4+ T cells. The cognate interaction between CD40L on T cells and CD40 on antigen-stimulated B cells, macrophage, and dendritic cells is critical for the development of a comprehensive immune response. The non-X-linked form of HIM syndrome is heterogeneous and appears in some cases to be a consequence of mutations in the AlD gene which encodes a B cell specific protein required for class switch recombination, somatic mutation, and germinal center formation. However, mutations in other unidentified genes are clearly the basis of the disease in a subset of patients. In this article, we review the essential features of the X-linked and non-X-linked forms of HIM syndrome and discuss the critical role the CD40:CD40L receptor-ligand pair plays in the pathogenesis of these immune deficiencies.


Subject(s)
CD40 Antigens/metabolism , CD40 Ligand/metabolism , Hypergammaglobulinemia/genetics , Hypergammaglobulinemia/immunology , Immunoglobulin M/blood , Immunologic Deficiency Syndromes/genetics , Immunologic Deficiency Syndromes/immunology , Animals , B-Lymphocytes/immunology , CD40 Antigens/genetics , CD40 Ligand/genetics , Disease Models, Animal , Female , Genetic Linkage , Humans , Immunoglobulin Class Switching , Male , Mice , Mutation , Signal Transduction , Transcription, Genetic , X Chromosome
15.
Biochem Pharmacol ; 53(2): 199-206, 1997 Jan 24.
Article in English | MEDLINE | ID: mdl-9037252

ABSTRACT

A human reduced folate carrier (hRFC) cDNA was transfected into transport-deficient K562 cells to circumvent complications that may result from carrier expression in a heterologous mammalian species. Relative to wild-type cells, hRFC transcript levels were increased 11- and 19-fold, respectively, in the K43-6 and K43-1 transfectants. Although photoaffinity labeling of hRFC protein revealed similar increases of 15- and 19-fold, respectively, only a 2-fold enhancement in methotrexate (Mtx) transport was observed. This suggests that only a small portion of the cDNA-encoded hRFC protein is actively engaged in membrane transport. Kinetic analysis of [3H]Mtx transport indicated that K43-6 cells exhibited a similar affinity (Kt) but an increased Vmax (1.7-fold) when compared with K562 cells. The restored transport was similar to that of wild-type cells in its capacity to be trans-stimulated by intracellular folates and in its sensitivity to competitive transport inhibitors (1843U89, bromosulfophthalein, folic acid, leucovorin, and ZD1694) and to irreversible inhibition by N-hydroxysuccinimide-methotrexate. Further, deglycosylated photoaffinity-labeled hRFC protein in both K562 and K43-6 cells migrated at approximately 65-70 kDa on SDS-gels, consistent with the molecular mass from the predicted amino acid sequence. These data further establish that the expression of hRFC, alone, is sufficient to confer transport properties typical of the "classical" hRFC. However, the discrepancy between the stoichiometry of carrier expression and transport activity implies that membrane translocation of bound substrate may be regulated by additional undefined mechanisms.


Subject(s)
Carrier Proteins/physiology , Membrane Proteins , Membrane Transport Proteins , Biological Transport , Carrier Proteins/genetics , Humans , Leukemia, Erythroblastic, Acute/metabolism , Methotrexate/pharmacokinetics , Reduced Folate Carrier Protein , Transfection , Tumor Cells, Cultured
16.
Biochem Pharmacol ; 51(4): 477-82, 1996 Feb 23.
Article in English | MEDLINE | ID: mdl-8619893

ABSTRACT

Collateral resistance to cisplatin and methotrexate has been reported in several cell lines. A murine leukemia cell line (L1210/DDP) selected for cisplatin resistance also has been shown to be highly resistant to methotrexate. Of the mechanisms proposed for methotrexate resistance, only changes in methotrexate transport into the cells were found in an earlier report. Methotrexate enters mammalian cells via an active transport system. In the present study, we demonstrated that the transport into the cell may be impaired in the resistant cells due to altered tyrosine phosphorylation of a membrane protein with a molecular mass of 66 kDa. This alteration was manifested by altered tyrosine phosphorylation of the 66 kDa protein and may be an underlying modification that renders the cells resistant to methotrexate. These results suggest involvement of tyrosine phosphorylation in folate transport and methotrexate resistant in L1210/DDP cells.


Subject(s)
Cisplatin/toxicity , Drug Resistance, Neoplasm , Leukemia L1210/metabolism , Membrane Proteins/metabolism , Methotrexate/toxicity , Phosphoproteins/metabolism , Phosphotyrosine/metabolism , Affinity Labels , Animals , Biological Transport, Active , Blotting, Western , Clone Cells , Electrophoresis, Polyacrylamide Gel , Membrane Proteins/isolation & purification , Methotrexate/metabolism , Mice , Molecular Weight , Phosphoproteins/isolation & purification , Tumor Cells, Cultured
17.
Int J Oncol ; 11(5): 1025-33, 1997 Nov.
Article in English | MEDLINE | ID: mdl-21528300

ABSTRACT

A major limitation of cancer chemotherapy is development of resistance. In this study, we analyzed KB-3-1 cells and adriamycin-selected multidrug resistant sublines KB-A1 and KB-A10 cells for mechanisms of resistance. KB-A10 cells are 10-fold more resistant than KB-A1 cells but have lower P-glycoprotein. Of the known mechanisms of multidrug resistance, topoisomerase II and lung-resistance-related protein were altered between the resistant cell lines. Glutathione-S-transferase activity and multidrug-resistance-related protein levels were higher in the resistant cell lines compared to the sensitive cells but were similar in KB-A1 and KB-A10 cells. Results indicate differential regulation of mechanisms of resistance with stepwise selection.

18.
Cancer Chemother Pharmacol ; 37(4): 337-42, 1996.
Article in English | MEDLINE | ID: mdl-8548879

ABSTRACT

We report a murine leukemia cell variant (L1210/DDP), selected for cisplatin (DDP) resistance, to be cross-resistant to methotrexate (MTX). Cross-resistance of L1210 cells to DDP and MTX has been observed by others, and has also been recorded in P388 murine leukemia and SSC-25 human squamous carcinoma cells. We demonstrated that MTX resistance is not due to dihydrofolate reductase (DHFR) gene amplification, increased DHFR enzyme activity or decreased MTX binding to the target enzyme. Of the mechanisms commonly proposed for MTX resistance, only differences in transport were observed when comparing sensitive (L1210/0) and resistant (L1210/DDP) cells. Our results suggest that MTX resistance in L1210/DDP cells is due to altered methotrexate uptake.


Subject(s)
Antimetabolites, Antineoplastic/pharmacology , Antineoplastic Agents/pharmacology , Cisplatin/pharmacology , Leukemia L1210/physiopathology , Methotrexate/pharmacology , Animals , Blotting, Southern , Drug Resistance, Multiple , Drug Resistance, Neoplasm , Humans , Leukemia L1210/drug therapy , Leukemia L1210/enzymology , Mice , Peptide Synthases/metabolism , Tetrahydrofolate Dehydrogenase/metabolism , Time Factors , Tumor Cells, Cultured
19.
Neurosurgery ; 40(1): 141-51, 1997 Jan.
Article in English | MEDLINE | ID: mdl-8971836

ABSTRACT

OBJECTIVE: Glioblastoma multiforme is a malignant primary brain tumor associated with short patient survival despite aggressive treatment, in part because of its propensity to aggressively infiltrate into brain tissue. Glioblastoma multiforme is also unique because it is the only nonepithelial human tumor for which excessive activation of epidermal growth factor receptor (EGFR) has been consistently linked to tumor growth and patient survival, and EGFR activation promotes glioblastoma multiforme infiltration in vitro. METHODS: Cocultures of human glioblastoma spheroids (derived from three separate patients) and fetal rat brain aggregates were examined for infiltration using confocal microscopy, in the presence of 0 to 100 mumol/L genistein, a tyrosine kinase (TK) inhibitor, and 3 mumol/L tyrphostin A25, a specific EGFR-TK inhibitor. RESULTS: Infiltration (not attachment) was completely inhibited by genistein at 10 mumol/L, the IC20 for monolayer growth inhibition in two cell lines. Tyrphostin A25 at 3 mumol/L (the IC20 for monolayers) reduced invasion in a third cell line from 38.8 +/- 6.1% invasion-hour per hour (n = 5) to 2.9 +/- 1.2% invasion-hour per hour (n = 6) (P = 0.0002, two-tailed t test, 93% inhibition), and from 0.54 +/- 0.065% per hour (slope) to 0.028 +/- 0.018% per hour (P = 0.00001, 95% inhibition). Maximal percent invasion was reduced from 100 +/- 0 to 7.4 +/- 5.6% of the fetal rat brain aggregate. No change was detected in EGFR-associated tyrosine phosphorylation at those doses in monolayers by 32P immunolabeling, consistent with the known effects of low concentrations of TK inhibitors. An increase in expression of wild-type and truncated EGFR was demonstrated by Western blotting. Invasion was equally well inhibited by a monoclonal antibody to the high-affinity ligand binding domain of EGFR and not by antibody to an inactive domain. CONCLUSION: Our observations support the role of EGFR activation as a determinant by which glioblastoma invades normal brain tissue, and we show that invasion can be effectively inhibited at much lower concentrations of TK inhibitors than are necessary for growth suppression.


Subject(s)
Brain Neoplasms/pathology , Enzyme Inhibitors/pharmacology , ErbB Receptors/antagonists & inhibitors , Glioblastoma/pathology , Isoflavones/pharmacology , Nitriles/pharmacology , Protein-Tyrosine Kinases/antagonists & inhibitors , Tyrphostins , Animals , Brain/pathology , Cell Division/drug effects , Cell Movement/drug effects , Dose-Response Relationship, Drug , ErbB Receptors/physiology , Genistein , Humans , Microscopy, Confocal , Neoplasm Invasiveness , Protein-Tyrosine Kinases/physiology , Rats , Spheroids, Cellular/drug effects , Spheroids, Cellular/pathology
20.
Neurosurgery ; 44(3): 568-77; discussion 577-8, 1999 Mar.
Article in English | MEDLINE | ID: mdl-10069594

ABSTRACT

OBJECTIVE: Phospholipase C (PLC)-gamma is a cytosolic enzyme activated by several growth factor (GF) receptors (epidermal GF receptor [EGFR], platelet-derived GF receptor, and insulin-like GF 1 receptor), and its activation is associated with increased cell motility (but not cell proliferation) in nonglioma cell lines. Because up-regulated activation of EGFR has been consistently linked to poor patient survival in patients with glioblastoma multiforme (GBM) and because inhibition of EGFR activation by tyrosine kinase inhibitors prevents glioma infiltration in vitro, we hypothesized that inhibition of PLC-gamma activation would inhibit glioma cell invasiveness. METHODS: Our experimental model assesses tumor spheroid invasion of fetal rat brain spheroids by confocal microscopy. We treated U87 GBM spheroids, and those derived from a single patient, with the PLC inhibitor U73122. We also transfected rat C6 glioma cells with the PLCz complementary deoxyribonucleic acid coding for a dominant negative PLC-gamma1 src-homology-2/src-homology-3 peptide fragment, which blocks binding and activation of PLC-gamma1 by GF receptors. Two clones (C6F and C6E) were grown into spheroids and were tested for invasiveness in the spheroid model and for responsiveness to GFs in a standard in vitro motility assay. RESULTS: The infiltration rate of the patient GBM cell line overexpressing wild-type EGFR was reduced by 2 micromol/L U73122 from a slope (percent invasion/h) of 0.74+/-0.08 (with the inactive congener U73343) to 0.04+/-0.053 (P = 8 x 10(-7) by two-tailed t test, 92% reduction); the integral rate, another measure of invasion, was reduced from 49.7+/-13 percent-hours per hour to 13.6+/-12 (P = 0.002, 72% reduction). The U87 spheroid invasion rate was reduced by 0.5 micromol/L U73122 from 46.7+/-8.5 percent-hours per hour to 11.2+/-4.6 (P = 3 x 10(-5)); the slope decreased from 1.7+/-0.41 percent per hour to 0.35+/-0.14 (P = 0.0001). The C6F and C6E clones demonstrated attachment to and "surrounding" of the fetal rat brain aggregate but no true invasion by confocal or light microscopy. PLCz blocked the motility response to epidermal GF, platelet-derived GF, and insulin-like GF. There was a significant decrease in PLC-gamma1-associated tyrosine phosphorylation. CONCLUSION: These results support a key role for PLC-gamma activation as a common postreceptor pathway for GF-induced tumor infiltration and further identify PLC-gamma1 as a possible target for anti-invasive therapy for GBMs.


Subject(s)
Brain/embryology , Brain/enzymology , Cell Movement/physiology , Glioblastoma/metabolism , Growth Inhibitors/metabolism , Isoenzymes/metabolism , Receptors, Growth Factor/metabolism , Spheroids, Cellular/metabolism , Type C Phospholipases/metabolism , Animals , Disease Models, Animal , Neoplasm Invasiveness , Phospholipase C gamma , Rats , Rats, Sprague-Dawley , Tumor Cells, Cultured
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