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1.

001-es BibID:BIBFORM006025
Első szerző:Balázs Margit (sejtbiológus, molekuláris genetikus)
Cím:Fluorescent tetradecanoylphorbol acetate : a novel probe of phorbol ester binding domains / Balázs, M., Szöllösi, J., Lee, W. C., Haugland, R. P., Guzikowski, A. P., Fulwyler, M. J., Damjanovich, S., Feuerstein, B. G., Pershadsingh, H. A.
Dátum:1991
Megjegyzések:Protein kinase C (PKC) has a prominent role in signal transduction of many bioactive substances. We synthesized the fluorescent derivative, phorbol-13-acetate-12-N-methyl-N-4-(N,N'-di(2-hydroxyethyl)amino)-7-n itr obenz-2-oxa-1,3-diazole-aminododecanoate (N-C12-Ac(13)) of 12-O-tetradecanoylphorbol-13-acetate (TPA) to monitor the location of phorbol ester binding sites and evaluate its potential use as a probe of PKC in viable cells. The excitation maximum wavelength of N-C12-Ac(13) is close to 488 nm, facilitating its use in argon-ion laser flow and imaging cytometry. When incubated with 100 nM N-C12-Ac(13) at 25 degrees C, P3HR-1 Burkitt lymphoma cells accumulated the dye rapidly, reaching maximum fluorescence within 25 min, 20-fold above autofluorescence. Addition of unlabeled TPA significantly decreased the fluorescence of N-C12-Ac(13) stained cells in a dose-dependent manner indicating specific displacement of the bound fluoroprobe. Competitive displacement of [3H]-phorbol-12,13-dibutyrate ([3H]-PBu2) from rat brain cytosol with N-C12-Ac(13) gave an apparent dissociation constant (Kd) of 11 nM. N-C12-Ac(13) possessed biological activity similar to TPA. Like TPA (final concentration 65 nM) N-C12-Ac(13), at a lower concentration (51 nM), induced expression of Epstein-Barr viral glycoprotein in P3HR-1 cells, differentiation of promyelocytic HL60 cells, and caused predicted changes in the mitotic cycle of histiocytic DD cells. Microspectrofluorometric images of single cells labeled with N-C12-Ac(13) showed bright fluorescence localized intracellularly and dim fluorescence in the nuclear region, consistent with dye binding mainly to cytoplasmic structures and/or organelles and being mostly excluded from the nucleus. Because of the high level of non-specific binding of N-C12-Ac(13), this probe is not ideal for visualizing PKC in intact cells, but would be a valuable fluoroprobe to investigate the kinetic properties of purified PKC. Also, knowledge gained from these studies allows us to predict structures of fluorescent phorbols likely to have less non-specific binding and, consequently, be potentially useful for monitoring PKC in viable cells.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
analysis
Animal
Antigens,Viral
Binding Sites
Brain Chemistry
Cell Cycle
chemical synthesis
Cytosol
Dyes
Female
Flow Cytometry
Fluorescence
Fluorescence Polarization
Fluorescent Dyes
Gene Expression
Herpesvirus 4,Human
Image Processing,Computer-Assisted
immunology
metabolism
Oxadiazoles
pharmacology
Phorbol Esters
Protein Kinase C
Rats
Rats,Inbred Strains
Signal Transduction
Support,Non-U.S.Gov't
Support,U.S.Gov't,P.H.S.
Tetradecanoylphorbol Acetate
Tumor Cells,Cultured
Megjelenés:Journal of Cellular Biochemistry. - 46 : 3 (1991), p. 266-276. -
További szerzők:Szöllősi János (1953-) (biofizikus) Lee, W. C. Haugland, R. P. Guzikowski, A. P. Fulwyler, Mack J. Damjanovich Sándor (1936-2017) (biofizikus) Feuerstein, Burt G. Pershadsingh, Harrihar A.
Internet cím:elektronikus változat
Borító:

2.

001-es BibID:BIBFORM006026
Első szerző:Basu, Hirak S.
Cím:Effect of polyamine depletion on chromatin structure in U-87 MG human brain tumour cells / Basu, H. S., Sturkenboom, M. C., Delcros, J. G., Csokan, P. P., Szollosi, J., Feuerstein, B. G., Marton, L. J.
Dátum:1992
Megjegyzések:The chromatin structure of polyamine-depleted U-87 MG human brain tumour cells was studied by following the kinetics of digestion of cell nuclei by micrococcal nuclease and bovine pancreatic DNAase I. Cells growing in monolayers were treated with either alpha-difluoromethylornithine (DFMO), to deplete putrescine and spermidine, or N1,N14-bis(ethyl)homospermine (BE-4-4-4), to deplete putrescine, spermidine and spermine. BE-4-4-4 increased the initial rates of digestion and the magnitudes of limit digest by both enzymes; DFMO increased the limit digests without affecting initial digestion rates. Addition of 1 mM-putrescine 1 day after addition of DFMO reversed the effect of DFMO on limit digests. (Because polyamine uptake is low in cells treated with BE-4-4-4, and because putrescine does not reverse the growth-inhibitory effects of BE-4-4-4, reversal of the effects of BE-4-4-4 with putrescine was not attempted.) The increases in initial rates and limit digests did not result from changes in the lengths of nucleosomal or linker DNA, from blocks in cell-cycle progression, or from growth inhibition caused by DFMO or BE-4-4-4. Thus, because the limit digest is highest in cells with the lowest polyamine levels, it seems clear that the enhanced enzymic digestion of nuclei is caused by polyamine depletion and its possible effect on chromatin structure.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
analogs and derivatives
Brain Neoplasms
Cell Cycle
Cell Nucleus
Chromatin
Culture Media
Culture Media,Serum-Free
Deoxyribonuclease I
Dna
drug effects
Eflornithine
Enzymes
Human
Intracellular Fluid
Kinetics
metabolism
Micrococcal Nuclease
pathology
pharmacology
Polyamines
Putrescine
Spermidine
Spermine
Support,Non-U.S.Gov't
Support,U.S.Gov't,P.H.S.
Tumor Cells,Cultured
ultrastructure
Megjelenés:The Biochemical Journal. - 282 : Pt 3 (1992), p. 723-727. -
További szerzők:Sturkenboom, M. C. Delcros, J. G. Csokan, P. P. Szöllősi János (1953-) (biofizikus) Feuerstein, Burt G. Marton, Laurence J.
Internet cím:elektronikus változat
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3.

001-es BibID:BIBFORM006032
Első szerző:Delcros, J. G.
Cím:Differential effects of spermine and its analogues on the structures of polynucleotides complexed with ethidium bromide / Delcros J. G., Sturkenboom M. C., Basu, H. S., Shafer R. H., Szöllösi, J., Feuerstein, B. G., Marton, L. J.
Dátum:1993
Megjegyzések:The interactions of spermine and polyamine analogues with synthetic polynucleotides of various base sequences complexed with ethidium bromide (EB) were investigated using measurements of fluorescence intensity and steady-state fluorescence polarization. Spermine and polyamine analogues displaced some but not all of the EB bound to poly(dA-dT).poly(dA-dT) or poly(dG-dC).poly(dG-dC), suggesting that polyamines may stabilize these polynucleotides in a conformation with reduced affinity for EB. Modifications of the aliphatic backbone of spermine have pronounced effects on its ability to displace EB from poly(dA-dT).poly(dA-dT) but not from poly-(dG-dC).poly(dG-dC). Spermine and some but not all of the polyamine analogues caused fluorescence depolarization when they interacted with the complex of EB and poly(dA-dT).poly-(dA-dT). Neither spermine nor any of the analogues, however, induced fluorescence depolarization in the complex of EB with poly(dG-dC).poly(dG-dC) or poly(dA).poly(dT). This suggests that spermine and some spermine analogues induce structural changes specific to alternating A-T sequences.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
chemistry
Ethidium
Fluorescence
Fluorescence Polarization
Nucleic Acid Conformation
pharmacology
Poly dA-dT
Polyamines
Polydeoxyribonucleotides
Polynucleotides
Spectrometry,Fluorescence
Spermine
Support,Non-U.S.Gov't
Support,U.S.Gov't,P.H.S.
Megjelenés:The Biochemical Journal. - 291 : Pt 1 (1993), p. 269-274. -
További szerzők:Sturkenboom, M. C. Basu, Hirak S. Shafer, R. H. Szöllősi János (1953-) (biofizikus) Feuerstein, Burt G. Marton, Laurence J.
Internet cím:elektronikus változat
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4.

001-es BibID:BIBFORM006033
Első szerző:Feuerstein, Burt G.
Cím:alpha-Difluoromethylornithine alters calcium signaling in platelet-derived growth factor-stimulated A172 brain tumor cells in culture / Feuerstein, B. G., Szollosi, J., Basu, H. S., Marton, L. J.
Dátum:1992
Megjegyzések:alpha-Difluoromethylornithine (DFMO), an irreversible inhibitor of the polyamine biosynthetic enzyme ornithine decarboxylase, inhibits the growth of brain tumor cell lines and is undergoing clinical trials as a treatment for brain tumors. Platelet-derived growth factor (PDGF) is thought to regulate the growth and development of precursors of both normal and neoplastic astrocytic cells; calcium signaling is thought to play a role in the transduction of PDGF signals. Using laser fluorescence image cytometry, flow cytometry, and spectrofluorometry, we studied the effect of DFMO on the calcium signals induced by PDGF in A172 human glioblastoma cells. Four days of treatment with 5 mM DFMO substantially shortened PDGF-induced calcium signals. The effect was reversed more than 10 h but less than 24 h after putrescine treatment, even though polyamines were repleted 4 h after putrescine and spermidine were added. DFMO did not substantially affect intracellular calcium release or the timing of the opening and closing of plasma membrane calcium channels. These findings support the notion that calcium signaling may be a target for inhibitors of polyamine metabolism.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
analysis
Biogenic Polyamines
Brain Neoplasms
Calcium
Calcium Channels
Calcium Signaling
Cell Line
drug effects
Eflornithine
Flow Cytometry
Fluorescence
Glioblastoma
Human
Image Cytometry
Ion Channel Gating
metabolism
pathology
pharmacology
Platelet-Derived Growth Factor
Polyamines
Signal Transduction
Support, Non-U.S.Gov't
Support, U.S.Gov't,P.H.S.
Tumor Cells, Cultured
Megjelenés:Cancer Research. - 52 : 24 (1992), p. 6782-6789. -
További szerzők:Szöllősi János (1953-) (biofizikus) Basu, Hirak S. Marton, Laurence J.
Internet cím:elektronikus változat
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5.

001-es BibID:BIBFORM004634
035-os BibID:(scopus)0032101894 (wos)000073937700007
Első szerző:Nagy Péter (biofizikus)
Cím:EGF-induced redistribution of erbB2 on breast tumor cells : flow and image cytometric energy transfer measurements / Nagy, P., Bene, L., Balazs, M., Hyun, W. C., Lockett, S. J., Chiang, N. Y., Waldman, F., Feuerstein, B. G., Damjanovich, S., Szollosi, J.
Dátum:1998
Megjegyzések:erbB2, a member of the epidermal growth factor (EGF) receptor-type tyrosine kinase receptor family, is overexpressed in breast carcinomas with poor prognosis. We examined the cell surface association of this receptor with itself and with other cell surface proteins by the Forster-type fluorescence resonance energy transfer using whole antibodies and Fab fragments. We found that erbB2 molecules homoassociate in unstimulated SK-BR-3, BT474 and BT474-M (a metastatic version of the parent BT474 line) breast tumor cells, and that the interaction was enhanced by EGF treatment in suspensions of SK-BR-3 and BT474-M cells. BT474 cells (with low EGF receptor expression) and attached SK-BR-3 cells do not respond to EGF. Image microscopic energy transfer measurements found considerable pixel-by-pixel heterogeneity in the homoassociation state of erbB2. In accordance with the EGF-induced redistribution of erbB2, EGF receptor was found to be in close proximity to erbB2 in FRET measurements. By labeling different epitopes on erbB2 and the lipid bilayer, we were able to prepare an epitope map of erbB2 molecule. Our data suggest the existence of dynamic cell surface patterns of erbB2 and point to functions fulfilled by these molecular complexes.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
analysis
biosynthesis
Breast Neoplasms
Carcinoma
Cell Membrane
chemistry
drug effects
Energy Transfer
Epidermal Growth Factor
Female
Flow Cytometry
Fluorescence
Human
Hungary
metabolism
methods
Models
Molecular
pharmacology
Receptor
erbB-2
Receptors
Transferrin
Support
Non-U.S.Gov't
Tumor Cells,Cultured
Squamous Cell
ultrastructure
Megjelenés:Cytometry. - 32 : 2 (1998), p. 120-131. -
További szerzők:Bene László (1963-) (biofizikus) Balázs Margit (1952-) (sejtbiológus, molekuláris genetikus) Hyun, William C. Lockett, Steven J. Chiang, Nancy Y. Waldman, Frederick Feuerstein, Burt G. Damjanovich Sándor (1936-2017) (biofizikus) Szöllősi János (1953-) (biofizikus)
Internet cím:elektronikus változat
DOI
Borító:

6.

001-es BibID:BIBFORM006049
Első szerző:Pershadsingh, Harrihar A.
Cím:Effects of ciglitazone on blood pressure and intracellular calcium metabolism / Pershadsingh, H. A., Szollosi, J., Benson, S., Hyun, W. C., Feuerstein, B. G., Kurtz, T. W.
Dátum:1993
Megjegyzések:Ciglitazone is the prototype of the thiazolidinedione class of compounds currently being developed for the treatment of insulin resistance and non-insulin-dependent diabetes. The effects of thiazolidinediones on blood pressure and cell calcium metabolism are not well defined. In the obese Zucker rat, a widely studied model of insulin resistance associated with mild hypertension, we investigated the effects of ciglitazone on plasma insulin levels and mean arterial pressure. We also evaluated the effects of ciglitazone on the changes in cytosolic calcium induced by platelet-derived growth factor in A172 human glioblastoma cells and rat A10 vascular smooth muscle cells. Oral administration of ciglitazone, approximately 45 mg/kg per day for 4 weeks, induced significant reductions in plasma insulin levels (p < 0.001) and blood pressure (p < 0.05). Ciglitazone was also found to significantly attenuate the capacity of platelet-derived growth factor BB homodimer to induce sustained increases in intracellular free calcium. These findings suggest that thiazolidinediones may offer a novel pharmacological approach to the treatment of hypertension, and raise the possibility that these compounds may affect blood pressure not only by affecting insulin metabolism but also by modifying the cell calcium response to pressor agents, growth factors, or both.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Animal
blood
Blood Pressure
Calcium
drug effects
Female
Glioblastoma
Human
Insulin
Intracellular Membranes
metabolism
Obesity
pharmacology
Platelet-Derived Growth Factor
Rats
Rats,Zucker
Signal Transduction
Thiazoles
Tumor Cells,Cultured
Megjelenés:Hypertension. - 21 : 6 Pt 2 (1993), p. 1020-1023. -
További szerzők:Szöllősi János (1953-) (biofizikus) Benson, Steve Hyun, William C. Feuerstein, Burt G. Kurtz, Theodore W.
Internet cím:elektronikus változat
Borító:

7.

001-es BibID:BIBFORM050093
Első szerző:Petrás Miklós (orvos)
Cím:Molecular interactions of ErbB1 (EGFR) and integrin-β1 in astrocytoma frozen sections predict clinical outcome and correlate with Akt-mediated in vitro radioresistance / Miklós Petrás, Tamás Lajtos, Elza Friedländer, Álmos Klekner, Éva Pintye, Burt G. Feuerstein, János Szöllősi, György Vereb
Dátum:2013
ISSN:1522-8517
Megjegyzések:INTRODUCTION: Treatment of astrocytoma is frequently hampered by radioresistance of the tumor. In addition to overexpression of ErbB1/EGFR, functional crosstalk between receptor tyrosine kinases and cell adhesion molecules may also contribute to therapy resistance. METHODS: Acceptor photobleaching FRET was implemented on frozen sections of clinical astrocytoma to check the role of ErbB1-integrin-beta1 interaction. U251 glioma subclones were obtained by introducing extra CHR7 material or the ErbB1 gene to test the relevance and mechanism of this interaction in vitro. RESULTS: Grade IV tumors showed higher ErbB1 and integrin-beta1 expression and greater ErbB1-integrin-beta1 heteroassociation than did grade II tumors. Of these, the extent of molecular association was a single determinant of tumor grade and prognosis in stepwise logistic regression. In vitro, integrin-beta1 was upregulated, and radiosensitivity was diminished by ectopic ErbB1 expression. Great excess of ErbB1 provided colony forming advantage over medium excess but did not yield better radiation resistance or faster proliferation and decreased to medium level over time, whereas integrin-beta1 levels remained elevated and defined the extent of radioresistance. Increased expression of ErbB1 and integrin-beta1 was paralleled by decreasing ErbB1 homoassociation and increasing ErbB1-integrin-beta1 heteroassociation. Microscopic two-sided FRET revealed that pixels with higher ErbB1-integrin-beta1 heteroassociation exhibited lowed ErbB1 homoassociation, indicating competition for association partners among these molecules. Boosted Akt phosphorylation response to EGF accompanied this shift toward heteroassociation, and the consequentially increased radioresistance could be reverted by inhibiting PI3K. CONCLUSION: The clinically relevant ErbB1-integrin-beta1 heteroassociation may be used as a target of both predictive diagnostics and molecular therapy
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Biophysics
Cell Adhesion
Cell Adhesion Molecules
cell biology
EGFR
ErbB1
EXPRESSION FRET
Glioma
Hungary
In Vitro
methods
molecular interaction
Phosphorylation
Photobleaching
Receptor
tyrosine kinase
Research
therapy
TUMORS
Tyrosine
Molekulatudomány
Doktori iskola
Megjelenés:Neuro-Oncology. - 15 : 8 (2013), p. 1027-1040. -
További szerzők:Lajtos Tamás Friedländer Elza (1980-) (biofizikus) Klekner Álmos (1970-) (idegsebész) Pintye Éva (1955-) (fizikus) Feuerstein, Burt G. Szöllősi János (1953-) (biofizikus) Vereb György (1965-) (biofizikus, orvos)
Pályázati támogatás:K75752
OTKA
NK101337
OTKA
F-049050
OTKA
ETT 523/2003
Egyéb
ETT 362-01/2009
Egyéb
TÁMOP-4.2.1/B-09/1/KONV-2010-0007
TÁMOP
TÁMOP-4.2.2/B-10/1-2010-0024
TÁMOP
TÁMOP-4.2.2/A-11/1/KONV-2012-0025
TÁMOP
Internet cím:Szerző által megadott URL
DOI
Intézményi repozitóriumban (DEA) tárolt változat
Borító:

8.

001-es BibID:BIBFORM042489
Első szerző:Petrás Miklós (orvos)
Cím:Significance of Epidermal Growth Factor Receptor in the Radiation Resistance of Glioblastoma Tumors / Miklós Petrás, Tamás Lajtos, Éva Pintye, Burt G. Feuerstein, János Szöllősi, György Vereb
Dátum:2008
Megjegyzések:In the United States, a dramatically increased incidence and mortality of brain tumors have been observed over the past decades. Of the ~44 thousand new cases of primary malignant and benign brain tumors diagnosed per year, highgrade astrocytomas or multiform glioblastomas show particularly bad prognosis in spite of therapeutic developments. Current management of multiform glioblastoma includes the most extensive surgical resection possible, followed by adjuvant radio- and chemotherapy. However, treatment is frequently hampered by decreased radiosensitivity of the tumor. Recent studies revealed that subpopulations of glioblastoma cells show amplified checkpoint activation of the cell cycle upon ionizing radiation, which induces overactivation of DNA repair processes and leads to maintained proliferation rate as well as clinically observed radioresistance and recurrence of the tumor over time. In addition, overexpression of some transmembrane receptors has also been implicated in radioresistance. However, the role of the overexpressed proteins can only be interpreted reliably if their multi-faceted molecular interactions are properly characterized. Thus, based on recent evidence for the functional crosstalk between certain cell adhesion molecules andreceptor tyrosine kinases, we have examined the molecular interactions of the receptor tyrosine kinase EGFR and the cell adhesion molecule 1-integrin using flow cytometric and microscopic fluorescence resosnance energy transfer (FRET)measurements on two cellular model systems showing similar expression patterns to low and high grade astrocytomas. On the one hand, U251 glioblastoma clones established by introducing varying amounts of extra chromosome 7 into the cells, and on the other hand stable, high and low EGFR expressing transfenctant U251 NCI sublines were investigated. The results revealed that increased EGFR and 1-integrin expression levels correlate with stronger EGFR ? 1-integrin heteroassociation, while concurrently the EGFR homoassociation is decreased, suggesting that 1-integrins may dynamically modulate the homoassociation state of EGFR receptors. This functional relationship may play an important role in decreasing radiosensitivity and tumor progression, especially since the EGFR ? 1-integrin molecular interaction appears to promote radioresistance via the Akt pathway.
ISBN:978-0-7354-0611-7
Tárgyszavak:Orvostudományok Elméleti orvostudományok könyvfejezet
Megjelenés:Radiation Damage In Biomolecular Systems : Proceedings of the 5th International Conference (RADAM 2008) / ed. by Károly Tőkési, Béla Sulik. - p. 204-217. -
További szerzők:Lajtos Tamás Pintye Éva (1955-) (fizikus) Feuerstein, Burt G. Szöllősi János (1953-) (biofizikus) Vereb György (1965-) (biofizikus, orvos)
Internet cím:DOI
Intézményi repozitóriumban (DEA) tárolt változat
Borító:

9.

001-es BibID:BIBFORM006053
Első szerző:Szöllősi János (biofizikus)
Cím:Attachment of A172 human glioblastoma cells affects calcium signalling : a comparison of image cytometry, flow cytometry, and spectrofluorometry / Szollosi, J., Feuerstein, B. G., Hyun, W. C., Das, M. K., Marton, L. J.
Dátum:1991
Megjegyzések:The intracellular free calcium concentration ([Ca2+]i) of indo-1 loaded A172 human glioblastoma cells stimulated by platelet-derived growth factor (PDGF) was studied in cell suspensions by flow cytometry and spectrofluorometry and in confluent monolayers by laser image cytometry and spectrofluorometry. With all three techniques, the percentage of responsive cells, peak [Ca2+]i, and the duration of response were directly related, and the delay time was inversely related to PDGF dose. The maximum response occurred at a PDGF concentration of about 20 ng/ml. Basal and peak [Ca2+]i did not differ significantly from method to method even though different calibration procedures were used. Cells in suspension monitored by both spectrofluorometry and flow cytometry displayed significantly shorter calcium responses than attached cells. This did not appear to be a direct effect of trypsinization. Spectral analysis of indo-1 in cytoplasm, 40% glycerol, and aqueous solutions showed significant differences in the isosbestic point and quantum efficiency. Calibration of [Ca2+]i with spectrofluorometry is more accurate using the ratio of fluorescence intensities than the fluorescence intensities measured at either 405 or 485 nm.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
analysis
Calcium
Cell Separation
Chelating Agents
Comparative Study
Cytoplasm
drug therapy
Dyes
Flow Cytometry
Fluorescence
Fluorescent Dyes
Glioblastoma
Glioma
Glycerol
Human
Image Cytometry
Indoles
metabolism
pharmacology
Platelet-Derived Growth Factor
Spectrometry,Fluorescence
Support,Non-U.S.Gov't
Support,U.S.Gov't,P.H.S.
Tumor Cells,Cultured
Megjelenés:Cytometry. - 12 : 8 (1991), p. 707-716. -
További szerzők:Feuerstein, Burt G. Hyun, William C. Das, M. K. Marton, Laurence J.
Internet cím:elektronikus változat
Borító:

10.

001-es BibID:BIBFORM006054
Első szerző:Szöllősi János (biofizikus)
Cím:Calcium channels in PDGF-stimulated A172 cells open after intracellular calcium release and are not voltage-dependent / Szollosi, J., Feuerstein, B. G., Vereb, G., Pershadsingh, H. A., Marton, L. J.
Dátum:1991
Megjegyzések:Using laser image cytometry and Indo-1 fluorescence, we investigated the intracellular free Ca2+ concentration ([Ca2+]i) of confluent A172 human glioblastoma cells stimulated by the BB homodimer of platelet-derived growth factor (PDGF-BB). The shape of the calcium transients and the delay time between stimulation and the beginning of the transient varied considerably. The percentage of responsive cells, the peak [Ca2+]i and the duration of the response were directly related to PDGF-BB dose, while the delay time was inversely related; the maximal response occurred at a PDGF-BB concentration of 20 ng/ml. Studies with EGTA and inorganic calcium-channel blockers (Ni2+, La3+) showed that the increase of [Ca2+]i resulted from initial release of intracellular stores and subsequent calcium influx across the plasma membrane. Opening of calcium channels in the plasma membrane, monitored directly by studying Mn2+ quenching of Indo-1 fluorescence, was stimulated by PDGF-BB and blocked by La3+; the opening occurred 55 +/- 10 s after the initial increase in [Ca2+]i. Therefore, in these tumor cells, intracellular release always occurs before channel opening in the plasma membrane. Depolarization of cells with high extracellular [K+] did not generally induce calcium transients but did decrease calcium influx. L-type calcium-channel blockers (verapamil, nifedipine, and diltiazem) had little or no effect on the calcium influx induced by PDGF-BB. These results indicate that PDGF-BB induces calcium influx by a mechanism independent of voltage-sensitive calcium channels in A172 human glioblastoma cells.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Calcium
Calcium Channel Blockers
Calcium Channels
Dyes
Egtazic Acid
Electrophysiology
Fluorescence
Fluorescent Dyes
Glioblastoma
Human
Image Cytometry
Image Processing,Computer-Assisted
Indoles
Lanthanum
metabolism
pharmacology
Platelet-Derived Growth Factor
Signal Transduction
Support,Non-U.S.Gov't
Support,U.S.Gov't,P.H.S.
Tumor Cells,Cultured
Verapamil
Megjelenés:Cell Calcium. - 12 : 7 (1991), p. 477-491. -
További szerzők:Feuerstein, Burt G. Vereb György (1965-) (biofizikus, orvos) Pershadsingh, Harrihar A. Marton, Laurence J.
Internet cím:elektronikus változat
Borító:

11.

001-es BibID:BIBFORM004934
Első szerző:Szöllősi János (biofizikus)
Cím:ERBB-2 (HER2/neu) gene copy number, p185HER-2 overexpression, and intratumor heterogeneity in human breast cancer / Szollosi, J., Balazs, M., Feuerstein, B. G., Benz, C. C., Waldman, F. M.
Dátum:1995
Megjegyzések:Amplification of the ERBB-2 (HER-2/neu) gene is accompanied by overexpression of its cell surface receptor product, p185HER-2. Heterogeneity has been observed for both the gene copy number and the level of overexpression of its protein product. To better understand their relationship, correlation between the level of cellular expression of p185HER-2 and ERBB-2 gene amplification was studied in four human breast cancer cell lines (BT-474, SK-BR-3, MDA-453, and MCF-7) and in a primary human breast tumor sample. The relative expression of p185HER-2 was measured by immunofluorescence by using flow and/or image cytometry while correlated DNA analysis was performed on the same cells by fluorescence in situ hybridization to determine ERBB-2 gene and chromosome 17 copy numbers. Marked heterogeneity was observed in both protein expression and ERBB-2 copy number. Despite this heterogeneity, and in accordance with previous studies, the average levels of p185HER-2 expression correlated well with average ERBB-2 gene copy numbers in the four lines examined (r = 0.99). When the relationship between copy number and protein expression was studied on a cell-by-cell basis, p185HER-2 expression correlated with both the absolute number of ERBB-2 gene copies/cell (r = 0.59-0.63) and chromosome 17 copy number (r = 0.45-0.61). It is of interest that there was weak or no correlation between p185HER-2 protein expression and the ERBB-2 copy number:chromosome 17 copy number ratio (r = 0.0-0.25). In more than one-half of cells expressing a high level of p185HER-2, the chromosome 17 copy number was high (two or three times the average copy number), whereas < 2% of an unselected population had a high chromosome 17 copy number. Bromodeoxyuridine incorporation indicated that the S-phase-labeling index was homogeneous across various p185HER-2-expressing subpopulations in the SK-BR-3 cell line. Analysis of the primary breast tumor sample showed results similar to the cell lines, supporting the strong possibility of a mechanistic link among p185HER-2 overexpression, ERBB-2 amplification, and high chromosome 17 copy number.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
analysis
biosynthesis
Breast Neoplasms
Cell Line
Chromosomes,Human,Pair 17
Dna
Female
Fluorescence
Gene Amplification
Gene Dosage
Genes,erbB-2
genetics
Human
Hybridization
Image Cytometry
Receptor,erbB-2
Support,Non-U.S.Gov't
Support,U.S.Gov't,P.H.S.
Tumor Cells,Cultured
Megjelenés:Cancer Research. - 55 : 22 (1995), p. 5400-5407. -
További szerzők:Balázs Margit (1952-) (sejtbiológus, molekuláris genetikus) Feuerstein, Burt G. Benz, Christopher C. Waldman, Frederick
Internet cím:elektronikus változat
Borító:

12.

001-es BibID:BIBFORM006077
Első szerző:Vereb György (biofizikus, orvos)
Cím:Depletion of intracellular calcium stores facilitates the influx of extracellular calcium in platelet derived growth factor stimulated A172 glioblastoma cells / Vereb, G., Jr., Szollosi, J., Matyus, L., Balazs, M., Hyun, W. C., Feuerstein, B. G.
Dátum:1996
Megjegyzések:Calcium signaling in non-excitable cells is the consequence of calcium release from intracellular stores, at times followed by entry of extracellular calcium through the plasma membrane. To study whether entry of calcium depends upon the level of saturation of intracellular stores, we measured calcium channel opening in the plasma membrane of single confluent A172 glioblastoma cells stimulated with platelet derived growth factor (PDGF) and/or bradykinin (BK). We monitored the entry of extracellular calcium by measuring manganese quenching of Indo-1 fluorescence. PDGF raised intracellular calcium concentration ([Ca2+]i) after a dose-dependent delay (tdel) and then opened calcium channels after a dose-independent delay (tch). At higher doses (> 3 nM), BK increased [Ca2+]i after a tdel approximately 0 s, and tch decreased inversely with both dose and peak [Ca2+]i. Experiments with thapsigargin (TG), BK, and PDGF indicated that BK and PDGF share intracellular Ca2+ pools that are sensitive to TG. When these stores were depleted by treatment with BK and intracellular BAPTA, tdel did not change, but tch fell to almost 0 s in PDGF stimulated cells, indicating that depletion of calcium stores affects calcium channel opening in the plasma membrane. Our data support the capacitative model for calcium channel opening and the steady-state model describing quantal Ca2+ release from intracellular stores.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
antagonists and inhibitors
Biophysics
Bradykinin
Ca(2+)-Transporting ATPase
Calcium
Calcium Channel Blockers
Calcium Channels
Calcium Signaling
Dose-Response Relationship,Drug
drug effects
Fluorescence
Glioblastoma
Human
Hungary
Lanthanum
Manganese
metabolism
Neuroglia
pharmacology
Platelet-Derived Growth Factor
Signal Transduction
Support, Non-U.S. Gov't
Support, U.S.Gov't, Non-P.H.S.
Support, U.S.Gov't, P.H.S.
Terpenes
Thapsigargin
Tumor Cells,Cultured
Megjelenés:Cytometry. - 24 : 1 (1996), p. 64-73. -
További szerzők:Szöllősi János (1953-) (biofizikus) Mátyus László (1956-) (biofizikus) Balázs Margit (1952-) (sejtbiológus, molekuláris genetikus) Hyun, William C. Feuerstein, Burt G.
Internet cím:Intézményi repozitóriumban (DEA) tárolt változa
Borító:
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