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EGFR Overexpression (egfr + overexpression)
Selected AbstractsNew mechanism of transforming growth factor-, signaling in hepatoma: Dramatic up-regulation of tumor initiating cells and epidermal growth factor receptor expressionHEPATOLOGY RESEARCH, Issue 5 2009Takeshi Nishimura Aim:, Transforming growth factor-, (TGF-,) has dual activity in tumor cells. We studied the effect of TGF-, on tumor-initiating cells (TICs), which are similar in self-renewal and differentiation features to normal adult stem cells. Methods:, We used side population (SP) cells that exclude DNA binding dye Hoechst 33342 to obtain TICs, studied the differences in the kinetics of the SP cell response to TGF-, treatment between hepatic tumor cell lines, and performed gene analysis. Results:, SP cells from all cell lines have higher proliferative ability compared to non-SP cells and they are drug resistant. TGF-, treatment increased the percentage of SP cells (%SP) and the survival rate; chemotherapeutic drug resistance developed only in K-251 SP cells. Gene analysis showed that TGF-, up-regulated epidermal growth factor receptor (EGFR) only in K-251 cells. There were no EGFR mutations in K-251, which had been reported in lung cancer. Knockdown of Smad4 using the small-interfering RNA technique in K-251 cells inhibited EGFR overexpression and significantly decreased the %SP. In contrast, the JNK inhibitor had little effect on EGFR expression or the %SP. Conclusion:, TGF-, treatment of K-251 cells causes tumor progression and the anti-cancer drug resistant phenotype by increasing SP. [source] Amplification of the epidermal growth factor receptor gene in glioblastoma: An analysis of the relationship between genotype and phenotype by CISH methodNEUROPATHOLOGY, Issue 2 2008Tomomi Miyanaga We examined epidermal growth factor receptor (EGFR) overexpression and EGFR gene amplification using immunohistochemistry (IHC) and chromogenic in situ hybridization (CISH) in 109 glioblastomas, including 98 primary glioblastomas and 11 secondary glioblastomas. EGFR overexpression and EGFR gene amplification were found in 33% and 24% of glioblastoma, respectively, and all of those cases were primary glioblastoma. Large ischemic necrosis was significantly more frequent in primary glioblastomas than in secondary glioblastomas (54% vs. 18%), but pseudopalisading necrosis was not (65% vs. 54%). EGFR gene amplification was detected significantly more frequently in cases with both types of necrosis. Although glioblastomas with EGFR gene amplification invariably exhibited EGFR overexpression at the level of the whole tumor, tumor cells with EGFR gene amplification did not always show EGFR overexpression at the level of individual tumor cells. Cases of "strong" EGFR overexpression on IHC could be regarded as having EGFR gene amplification, and cases without EGFR overexpression could not. Cases of "weak" EGFR overexpression should be tested with CISH to confirm the presence of EGFR gene amplification. We found that 54% of glioblastomas with EGFR gene amplification were composed of areas with and without EGFR gene amplification; however, there were no obvious differences in morphology between tumor cells with and without EGFR gene amplification. Although small cell architecture might be associated with EGFR gene amplification at the level of the whole tumor, it did not always suggest amplification of the EGFR gene at the level of individual tumor cells. In one case, it seemed to suggest that a clone with EGFR gene amplification may arise in pre-existing tumor tissue and extend into the surrounding area. In cases of overall EGFR amplification, CISH would be a useful tool to decide the tumor border in areas infiltrated by tumor cells. [source] Frequent overexpression of multiple ErbB receptors by head and neck squamous cell carcinoma contrasts with rare antibody immunity in patientsTHE JOURNAL OF PATHOLOGY, Issue 3 2004Roberto Bei Abstract In an effort to elucidate the role of ErbB receptors in human head and neck squamous cell carcinoma (HNSCC), expression abnormalities and subcellular localization of epidermal growth factor receptor (EGFR), ErbB2, ErbB3, and ErbB4 were investigated along with EGF and tenascin by immunohistochemistry in 38 carcinomas as compared to adjacent normal mucosa of 24 cases. Although tumour-specific overexpression affected each ErbB receptor (EGFR 47%, ErbB2 29%, ErbB3 21%, ErbB4 26%), EGFR abnormalities were most prevalent. The latter, and overexpression of more than two ErbB receptors in the same tumour, which always included EGFR, correlated with metastatic disease. ErbB products were specifically detected on the cell membrane and in the cytoplasm. In contrast, ErbB4 was uniquely localized to the nucleus in 7 carcinomas and a tumour-derived cell line, indicating a role for regulated intramembrane proteolysis resulting in nuclear ErbB4 translocation in HNSCC. Expression of prototype ligand EGF or low-affinity stromal activator tenascin correlated significantly with EGFR overexpression, implying chronic EGFR activation. Simultaneous overexpression of additional ErbB receptors in most of these cases suggested recurrent involvement of receptor heterodimers. In spite of frequent ErbB receptor alterations, autologous ErbB serum antibodies were rare, with only 1 of 38 tumour patients exhibiting an ErbB2-specific immune response. Based on upregulation of several known immunosuppressive molecules, scarcity of ErbB-specific antibodies is consistent with attenuation of natural tumour-specific immune responses in HNSCC. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [source] Predominant Expression of Mutant EGFR (EGFRvIII) is Rare in Primary GlioblastomasBRAIN PATHOLOGY, Issue 2 2004Wojciech Biernat EGFR amplification is a frequent genetic alteration in primary (de novo) glioblastomas, and is often associated with structural alterations. Most common is variant III (EGFRvIII), which results from a non-random 801 bp in-frame deletion of exons 2 to 7 of the EGFR gene. We assessed amplification and overexpression of EGFRvIII and wild-type EGFR in 30 glioblastoma biopsies. Immunohistochemically, EGFR overexpression was observed in 20 (67%) of 30 glioblastomas. Eight (27%) cases also showed immunoreactivity to an EGFRvIII antibody. In 6 of these cases, the pattern of EGFR and EGFRvIII overexpression was compared in serial sections: In 4 cases, areas with immunoreactivity to EGFRvIII largely coincided with wild-type EGFR expression. In the other 2 cases, the areas immunoreactive to EGFRvIII were significantly less extensive than EGFR-positive areas. To assess whether EGFRvIII is predominantly amplified in tumors with concurrent wild-type EGFR amplification, we carried out real-time quantitative PCR using 2 sets of primers located in exon 2 and intron 15 of the EGFR gene. A>5-fold ratio of relative copy numbers between intron 15 (present both in wild-type EGFR and EGFRvIII) and exon 2 (present only in wild-type EGFR, but missing in EGFRvIII) suggested predominant amplification of EGFRvIII in only 3 (10%) of 30 glioblastomas. The observation that intratumoral wild-type EGFR overexpression is often more extensive and that predominant amplification of EGFRvIII is a rare event would limit the effectiveness of therapeutic approaches based on selective targeting of EGFRvIII. [source] Different expression patterns of KIT, EGFR, and HER-2 (c-erbB-2) oncoproteins between epithelial and mesenchymal components in uterine carcinosarcomaCANCER SCIENCE, Issue 11 2003Morio Sawada Uterine carcinosarcoma histologically comprises the components of epithelial and mesenchymal malignancies, and is known to be clinically highly aggressive. To reveal the significance of the expression of tyrosine-kinase-receptor-type oncoproteins in this tumor type, the incidence and distribution of the KIT, EGFR, and HER-2 (c-erbB-2) oncoproteins were immunohistochemically examined in 16 surgically resected cases. For 6 cases, the EGFR and HER-2 amplifications were also examined by fluorescence in situ hybridization (FISH). In the epithelial component, overexpressions of KIT, EGFR, and HER-2 were detected in 4 (25%), 5 (31%), and 9 (56%) cases, respectively, whereas these overexpressions in the mesenchymal component were detected in 6 (38%), 8 (50%), and 1 (6%) cases, respectively. KIT and EGFR were co-overexpressed in the mesenchymal component of 4 cases and in the epithelial component of 2 cases. However, HER-2 overexpression was mostly detected in the epithelial component only, and tended to occur independently of KIT and/or EGFR overexpression. By FISH, one of the 4 cases with HER-2 overexpression showed low-level gene amplification. In two cases with EGFR overexpression, the gain of EGFR alleles and/or polyploidization of chromosome 7 had occurred. The expression patterns of KIT, EGFR, and HER-2 differed between the epithelial and mesenchymal components, and the regulation of their expression appeared important in the acquisition of mesenchymal metaplasia in uterine carcinosarcoma. Structural and/or numerical alterations of chromosomes might be in part involved in EGFR and/or HER-2 overexpression in this tumor type. [source] Transient transfection of epidermal growth factor receptor gene into MCF7 breast ductal carcinoma cell lineCELL BIOCHEMISTRY AND FUNCTION, Issue 3 2005Majed S. Alokail Abstract Epidermal growth factor receptor (EGFR) is activated by autocrine growth factors in many types of tumours, including breast tumours. This receptor has been linked to a poor prognosis in breast cancer and may promote proliferation, migration, invasion, and cell survival as well as inhibition of apoptosis. Human breast ductal carcinoma MCF7 cells were transfected using FuGENEÔ 6 with 1,,g of pcDNA3-EGFR containing the full-length human EGFR promoter or 1,,g of the vectors alone (pcDNA3). The transfected cells were transferred into a 25-cm2 flask containing growth medium and G418. Confluent cultures were lysed, total protein levels measured and electrophoresed. The electrophoresed samples were transferred to nitrocellulose and incubated overnight at 4°C with either anti-EGFR or anti-phospho-ERK and immunoreactive bands were visualized using HRP-linked secondary antibody. We created a model system of EGFR overexpression in MCF7 clones with stably transfected pcDNA3/EGFR plasmid. These cells have been shown to promote substantial phosphorylation of both ERK1 and ERK2. The high level of EGFR and ERK1/2 phosphorylation was not seen in the pcDNA3 vector control cells or in non-transfected cells. In this article we describe successful transient transfection experiments on MCF7 cells using the FuGENEÔ 6 Transfection Reagent. The overexpression of EGFR could be a mediated stress response and a survival signal that involves ERK1 and ERK2 phosphorylation. Copyright © 2004 John Wiley & Sons, Ltd. [source] | ||||||||||