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001-es BibID:BIBFORM004864
035-os BibID:(scopus)26444452209 (wos)000232299300016
Első szerző:Friedländer Elza (biofizikus)
Cím:Signal transduction of erbB receptors in trastuzumab (Herceptin) sensitive and resistant cell lines : local stimulation using magnetic microspheres as assessed by quantitative digital microscopy / Friedlander, E., Arndt-Jovin, D. J., Nagy, P., Jovin, T. M., Szollosi, J., Vereb, G.
Dátum:2005
ISSN:1552-4922
Megjegyzések:ErbB2 (HER-2), a member of the epidermal growth factor (EGF) receptor family, is a class I transmembrane receptor tyrosine kinase. Although erbB2 has no known physiologic ligand, it can form complexes with other members of the family and undergo transactivation of its very potent kinase activity, thereby initiating downstream signaling and cell proliferation. ErbB2 is a frequent pathologic marker in ductal invasive breast carcinomas and is targeted by using a specific humanized monoclonal antibody, trastuzumab (Herceptin). The antibody is effective in only 20% to 50% of erbB2-positive tumors, and this resistance, as yet poorly understood, constitutes a major therapeutic challenge. METHODS: Magnetic microspheres coated with ligands or antibodies are widely used for separation of proteins and cells and allow localized, high intensity, and precisely timed stimulation of cells. We used EGF- and trastuzumab-covered paramagnetic microspheres, quantitative confocal laser scanning microscopy, and digital image processing to investigate the (trans)activation of and local signal propagation from erbB1 and erbB2 on trastuzumab sensitive and resistant carcinoma cell lines expressing these receptors at high levels. RESULTS: On A431 cells expressing high levels of endogenous erbB1 and transfected erbB2-mYFP (A4-erbB2-mYFP F4 cell line), EGF-coupled-microspheres activated erbB1 and transactivated erbB2-mYFP. In two other cell lines with comparable erbB2 expression but lower levels of erbB1, EGF microspheres transactivated erbB2 less efficiently. Trastuzumab in solution activated erbB2 on A4-erbB2-mYFP and the trastuzumab sensitive SKBR-3 cells, but only negligibly on the resistant JIMT-1 cells that showed a 10 times higher K(d) for the antibody. Nevertheless, pronounced erbB2 activation and tyrosine phosphorylation could be detected after stimulation with trastuzumab-coupled microspheres in all cell lines, although transactivation of erbB1 was negligible. Receptor phosphorylation was restricted to the immediate proximity of the microspheres, i.e., receptor clusters external to these locations remained inactive. CONCLUSION: ErbB1 ligand and erbB2 specific antibody attached to magnetic microspheres are efficient tools in assessing erbB activation, localized signal propagation, and erbB heterodimer formation. Trastuzumab coupled to microspheres is more efficient at accessing erbB2 and activating it than trastuzumab in solution
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Animals
Antibodies
Antibodies,Monoclonal
Biophysics
Carcinoma
Cell Line
Cell Line,Tumor
Cell Proliferation
Cells
chemistry
drug effects
Drug Resistance,Neoplasm
Epidermal Growth Factor
genetics
Humans
Hungary
Ligands
Magnetics
metabolism
methods
Microscopy
Microspheres
pharmacology
Phosphorylation
Proteins
Receptor,erbB-2
Research
Signal Transduction
Solubility
Support
Trans-Activation (Genetics)
Megjelenés:Cytometry. Part A. - 67 : 2 (2005), p. 161-171. -
További szerzők:Arndt-Jovin, Donna J. Nagy Péter (1971-) (biofizikus) Jovin, Thomas M. Szöllősi János (1953-) (biofizikus) Vereb György (1965-) (biofizikus, orvos)
Internet cím:elektronikus változat
DOI
Borító:

2.

001-es BibID:BIBFORM111996
Első szerző:Nagy Péter (biofizikus)
Cím:Novel single cell fluorescence approaches in the investigation of signaling at the cellular level / Péter Nagy, György Vereb, Janine N. Post, Elza Friedländer, János Szőllősi
Dátum:2005
ISSN:0932-2353
ISBN:9783540250647
Tárgyszavak:Orvostudományok Elméleti orvostudományok könyvfejezet
könyvrészlet
Megjelenés:Biophysical aspects of transmembrane signaling / szerk. Damjanovich Sándor. - p. 33-70. -
További szerzők:Vereb György (1965-) (biofizikus, orvos) Post, Janine N. Friedländer Elza (1980-) (biofizikus) Szöllősi János (1953-) (biofizikus)
Internet cím:Intézményi repozitóriumban (DEA) tárolt változat
Borító:

3.

001-es BibID:BIBFORM004879
Első szerző:Nagy Péter (biofizikus)
Cím:Decreased accessibility and lack of activation of ErbB2 in JIMT-1, a herceptin-resistant, MUC4-expressing breast cancer cell line / Nagy, P., Friedlander, E., Tanner, M., Kapanen, A. I., Carraway, K. L., Isola, J., Jovin, T. M.
Dátum:2005
ISSN:0008-5472
Megjegyzések:Overexpression of erbB2 in breast tumors is associated with poor prognosis and is a target of receptor-oriented cancer therapy. Trastuzumab (Herceptin), a monoclonal antibody against a membrane-proximal epitope in the extracellular region of erbB2, shows a therapeutic effect against a fraction of erbB2-amplified breast tumors. Unfortunately, resistance to Herceptin is common, and its cause is as yet unclear. Here we investigated the properties of erbB2 in a Herceptin-resistant cell line, JIMT-1, established from a breast cancer patient showing erbB2 gene amplification and primary resistance to Herceptin. The expression profile of erbB proteins, Herceptin-induced erbB2 internalization, and down-regulation in JIMT-1 were similar to those in Herceptin-sensitive lines. However, the mean number of Herceptin Mab binding sites in JIMT-1 was 1/5 that of the expressed erbB2 molecules, although 5% to 10% of the cells showed a approximately 10-fold higher Herceptin binding than the main population. Herceptin Fab and Mab 2C4, an antibody binding to an epitope in the ectodomain further removed from the membrane, bound more efficiently to JIMT-1 cells than Herceptin Mab, implying that erbB2 was partly masked. The expression of MUC4, a membrane-associated mucin that according to reports contributes to the masking of membrane proteins, was higher in JIMT-1 than in Herceptin-sensitive lines, and its level was inversely correlated with the Herceptin binding capacity of single cells. Knockdown of MUC4 expression by RNA interference increased the binding of Herceptin. Western blotting showed a low level of proteolytic processing, shedding, and tyrosine phosphorylation of erbB2 in JIMT-1. The latter finding may explain its Herceptin-resistant phenotype characterizing both the low and high Herceptin binding subpopulations. We conclude that masking of erbB2 in JIMT-1 leads to diminished Herceptin binding and isolation of erbB2 from its normal interaction and activation partners.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Antibodies
Antibodies,Monoclonal
Antineoplastic Agents
Binding Sites
biosynthesis
Breast Neoplasms
Cell Line
Cell Line,Tumor
Cells
chemistry
Down-Regulation
Drug Resistance,Neoplasm
drug therapy
Enzyme Activation
enzymology
Epitopes
Gene Amplification
Humans
immunology
Membrane Proteins
metabolism
Metalloproteases
Mucins
pharmacology
Phenotype
Phosphorylation
Proteins
Receptor,erbB-2
Research
Support
therapy
Tyrosine
Megjelenés:Cancer Research. - 65 : 2 (2005), p. 473-482. -
További szerzők:Friedländer Elza (1980-) (biofizikus) Tanner, Minna Kapanen, Anita I. Carraway, Kermit L. Isola, Jorma Jovin, Thomas M.
Internet cím:elektronikus változat
Borító:
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