Egfr - Epidermal growth factor receptor
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Pubmed
Journal: APMIS : acta pathologica, microbiologica, et immunologica Scandinavica
March/4/2009
Abstract
This study aimed to determine whether epidermal growth factor receptor (EGFR), which has been reported to be frequently overexpressed in esophageal carcinoma cells, is actually activated in the cells. Paraffin-embedded specimens of 39 cases of esophageal carcinoma were analyzed immunohistochemically with anti-EGFR polyclonal antibody (alpha-EGFR Ab) and also an anti-phospho-EGFR-specific polyclonal antibody (alpha-p-EGFR(Tyr992) Ab) that specifically recognizes phosphorylated tyrosine 992 of EGFR. All of the 39 cases were found to express EGFR, but the expression levels were not significantly higher than those in basal cells of the normal esophageal epithelium. In 38 of the 39 cases, alpha-p-EGFR(Tyr992) immunoreactivity was evident. Interestingly, the positively stained carcinoma cells were not distributed diffusely, and strongly immunostained cells tended to be localized in areas of severe dysplasia and in microinvasive foci just adjacent to the main invasive carcinoma. However, the deeply invasive front never exhibited positive immunoreactivity. The present findings suggest that phosphorylation of EGFR( Tyr992) may play some specific functional role in esophageal carcinomas besides promotion of cell proliferation.
Pubmed
Journal: Stem cells (Dayton, Ohio)
February/27/2013
Abstract
Hair follicles (HFs) are equipped with stem cell niches that allow regeneration. Tumor necrosis factor-α converting enzyme (TACE), also known as A disintegrin and metalloproteinase 17, is a proteolytic enzyme that regulates a variety of cell surface molecules including TNF-α, via ectodomain shedding. We found TACE expression on mouse HFs and conditionally depleted it in cells that expressed sex-determining region Y-related high-mobility-group box 9 (SOX9) transcription factor, an HF stem cell transcription factor (Tace(flox/flox) -Sox9-Cre, hereafter, "Tace/Sox9"). Tace/Sox9 mice were born with brittle hair with prolonged anagen phase. They underwent diffuse, progressive, and ultimately whole-body hair loss by 20 weeks old. Tace/Sox9 HFs lacked CD34(+) bulge cells as demonstrated via immunofluorescence microscopy and flow cytometry. Real-time PCR revealed downregulation of transcription factors Sox9, Lhx2, and Gata3 and upregulation of Lef1. In vitro colony-forming capacity was abolished in Tace/Sox9 keratinocytes, and HFs exhibited increased proliferation in situ, collectively demonstrating that Tace/Sox9 mice failed to establish the bulge niche and to maintain "stemness" of HF stem cells. Epidermal growth factor receptor (EGFR) signaling was impaired in Tace/Sox9 keratinocytes, and mice depleted of Egfr in SOX9-expressing tissues exhibited hair phenotype nearly identical to Tace/Sox9 mice, demonstrating EGFR signaling as a pathway downstream of TACE in HF homeostasis. This study provides mechanistic implication for human TACE-deficiency and for hair abnormality caused by EGFR inhibitors.
Pubmed
Journal: Biophysical journal
October/31/2010
Abstract
Classical theory states that ligand binding induces the dimerization of ErbB proteins, leading to their activation. Although we and other investigators have shown the existence of preformed homoclusters of ErbB receptors and analyzed their composition, the stoichiometry of their heteroclusters has not been quantitatively described. Here, we report the development of the fluorescence resonance energy transfer (FRET)-sensitized acceptor bleaching (FSAB) technique to quantitate the ratio of ErbB1 and ErbB2 in their heteroclusters. In FSAB, photolabile acceptors within FRET distance from photostable donors are excited and photobleached by FRET, and the fraction of acceptors that are participating in FRET is determined. In quiescent SKBR-3 breast cancer cells, approximately 35% of ErbB1 and approximately 10% of ErbB2 have been found in heteroclusters. Epidermal growth factor (ligand of ErbB1) increased the fraction of ErbB2 heteroclustering with ErbB1, whereas the ratio of heteroclustered ErbB1 did not change significantly. The fractions of heteroclustered ErbB1 and ErbB2 were independent of their expression levels, indicating that the formation of these clusters is not driven by the law of mass action. In contrast, the FRET efficiency depended on the donor/acceptor ratio as expected. We present a model in which preformed receptor clusters are rearranged upon ligand stimulation, and report that the composition of these clusters can be quantitatively described by the FSAB technique.
Pubmed
Journal: Tissue & cell
March/23/2017
Abstract
BACKGROUND
Skin stem cell populations reside in the adult hair follicle, sebaceous gland, dermis and epidermis. However, the origin of most of the stem cell populations found in the adult epidermis is still unknown. Far more unknown is the embryonic origin of other stem cells that populate the other layers of this tissue.
OBJECTIVE
The main objectives of the present study were to identify the precise anatomical localization of stem cells in mice during skin developing; and to determine the expression levels by using immuno- and gene expression analysis.
METHODS
In this comparative cross sectional study, six ages been chosen and divided into: embryonic days (E12.5, E14.5 and E19.5) and litter days (L7, L14 and L19). Skin were removed from the back side and processed to assess both immuno- and gene-expression of EGFR and Nestin surface antigen markers. Data of the different studied age groups was compared using the SPSS software.
RESULTS
EGFR was mainly expressed in the outer root sheath (ORS), in basal and, to a lesser extent, in suprabasal keratinocytes and tend to lie where the dermis comes closest to the skin surface, while Nestin expressed throughout the dermis in the early embryo, but it is subsequently restricted to the follicular connective tissue sheaths later in development and to hair follicles after birth. Immunoexpression analysis showed a strong EGFR expression in all group ages except E12.5 which recorded as moderate, while Nestin showed strong expression level for all embryonic stages, while in the litters it was moderate. The qRT-PCR results were consistent with those of the immunohistochemical study. The Pearson correlation analyze present a correlation between the cases of study with age (p≤0.01), which indicated to the effect of age to mice development.
CONCLUSIONS
EGFR and Nestin showed to have vital role during mice development, and considered to be suitable markers for the study of skin stem cells.
Pubmed
Journal: Cytogenetic and genome research
February/29/2016
Abstract
Lung cancer, especially non-small cell lung cancer (NSCLC), is the major cause of cancer death worldwide. Mutations in epidermal growth factor receptor (EGFR) and hepatocyte growth factor receptor (c-Met), both of which are receptor tyrosine kinases, have been identified in a considerable percentage of NSCLC patients. EGFR and c-Met share the same downstream pathways and cooperate not only in promoting metastasis but also in conferring resistance to tyrosine kinase inhibitor (TKI) therapies in NSCLC. MicroRNAs (miRNAs) are a family of small non-coding RNAs, usually 21-25 nucleotides long, and are critical in regulating gene expression. Abnormal miRNA expression has been implicated in the initiation and progression in many forms of cancers, including lung cancer. In this study, we found that miR-200a is downregulated in NSCLC cells, where it directly targets the 3'-UTR of both EGFR and c-Met mRNA. Overexpression of miR-200a in NSCLC cells significantly downregulates both EGFR and c-Met levels and severely inhibits cell migration and invasion. Moreover, in NSCLC cell lines that are resistant to gefitinib, a drug often used in TKI therapies to treat NSCLC, miR-200a expression is able to render the cells much more sensitive to the drug treatment.
Pubmed
Journal: Cell adhesion & migration
September/8/2010
Abstract
EGFR, a critical regulator of oncogenic signaling during cancer progression, is capable of integrating multireceptor signaling pathways that promote metastasis. EGFR is subject to regulatory cues from the extracellular matrix (ECM), of which hyaluronan (HA) is a major component. In mammary tumors, HA is deposited in the ECM where it functions in biomechanical support and modulates intracellular signaling. We utilized a 3D collagen system in which HA is either polymerized in collagen matrix or provided soluble in the media (sHA). Here we report that collagen-embedded HA (eHA) inhibits EGFR activation, filopodia formation and cell spreading on a collagen matrix. These findings demonstrate a novel role for eHA as a protective molecule when encountered in the collagen matrix during cancer progression.
Pubmed
Journal: The Journal of biological chemistry
January/6/1997
Abstract
brk (breast tumor kinase) shows homology to the src family of non-receptor protein-tyrosine kinases and is expressed in breast carcinomas. In order to investigate the role of brk in breast tumor development, we have examined the growth and transformation properties of human mammary epithelial cells engineered to overexpress Brk. Interestingly, like c-Src, overexpression of Brk leads to sensitization to EGF, and also results in a partially transformed phenotype. Further investigation of the latter activity was attempted by mutational analysis, targeting key residues known to affect tyrosine kinase activity in Src-like kinases. Mutation of amino acid residue Lys-219 to Met, by analogy to Src, abolished both kinase activity and transformation capacity. Mutation of amino acid residue Tyr-447 to Phe, however, resulted in a decrease in transforming potential without affecting kinase activity. These results suggest that while Src and Brk share some functional properties, they act differently during transformation. These differences are discussed in the context of the mechanisms underlying breast cancer development.
Pubmed
Journal: Development (Cambridge, England)
January/22/1997
Abstract
The induction of different cell fates along the dorsoventral axis of the Drosophila embryo requires a graded activity of the EGF receptor tyrosine kinase (DER). Here we have identified primary and secondary target genes of DER, which mediate the determination of discrete ventral cell fates. High levels of DER activation in the ventralmost cells trigger expression of the transcription factors encoded by ventral nervous system defective (vnd) and pointed P1 (pntPl). Concomitant with the induction of pntP1, high levels of DER activity lead to inactivation of the Yan protein, a transcriptional repressor of Pointed-target genes. These two antagonizing transcription factors subsequently control the expression of secondary target genes such as otd, argos and tartan. The simultaneous effects of the DER pathway on pntP1 induction and Yan inactivation may contribute to the definition of the border of the ventralmost cell fates.
Pubmed
Journal: PloS one
July/2/2015
Abstract
Anti-EGFR therapy is commonly used to treat colorectal cancer (CRC), although only a subset of patients benefit from the treatment. While KRAS mutation predicts non-responsiveness, positive predictive markers are not in clinical practice. We previously showed that immunohistochemistry (IHC)-guided EGFR gene copy number (GCN) analysis may identify CRC patients benefiting from anti-EGFR treatment. Here we tested the predictive value of such analysis in chemorefractory metastatic CRC, elucidated EGFR GCN heterogeneity within the tumors, and evaluated the association between EGFR GCN, KRAS status, and anti-EGFR antibody response in CRC cell lines. The chemorefractory patient cohort consisted of 54 KRAS wild-type (WT) metastatic CRC patients. EGFR GCN status was analyzed by silver in situ hybridization using a cut-off value of 4.0 EGFR gene copies/cell. KRAS-WT and KRAS mutant CRC cell lines with different EGFR GCN were used in in vitro studies. The chemorefractory CRC tumors with EGFR GCN increase (≥4.0) responded better to anti-EGFR therapy than EGFR GCN (<4.0) tumors (clinical benefit, P = 0.0004; PFS, HR = 0.23, 95% CI 0.12-0.46). EGFR GCN counted using EGFR IHC guidance was significantly higher than the value from randomly selected areas verifying intratumoral EGFR GCN heterogeneity. In CRC cell lines, EGFR GCN correlated with EGFR expression. Best anti-EGFR response was seen with KRAS-WT, EGFR GCN = 4 cells and poorest response with KRAS-WT, EGFR GCN = 2 cells. Anti-EGFR response was associated with AKT and ERK1/2 phosphorylation, which was effectively inhibited only in cells with KRAS-WT and increased EGFR GCN. In conclusion, IHC-guided EGFR GCN is a promising predictor of anti-EGFR treatment efficacy in chemorefractory CRC.
Pubmed
Journal: Current biology : CB
March/8/2010
Abstract
BACKGROUND
The epidermal growth factor (EGF) stimulates rapid tyrosine phosphorylation of the EGF receptor (EGFR). This event precedes signaling from both the plasma membrane and from endosomes, and it is essential for recruitment of a ubiquitin ligase, CBL, that sorts activated receptors to endosomes and degradation. Because hyperphosphorylation of EGFR is involved in oncogenic pathways, we performed an unbiased screen of small interfering RNA (siRNA) oligonucleotides targeting all human tyrosine phosphatases.
RESULTS
We report the identification of PTPRK and PTPRJ (density-enhanced phosphatase-1 [DEP-1]) as EGFR-targeting phosphatases. DEP-1 is a tumor suppressor that dephosphorylates and thereby stabilizes EGFR by hampering its ability to associate with the CBL-GRB2 ubiquitin ligase complex. DEP-1 silencing enhanced tyrosine phosphorylation of endosomal EGFRs and, accordingly, increased cell proliferation. In line with functional interactions, EGFR and DEP-1 form physical associations, and EGFR phosphorylates a substrate-trapping mutant of DEP-1. Interestingly, the interactions of DEP-1 and EGFR are followed by physical segregation: whereas EGFR undergoes endocytosis, DEP-1 remains confined to the cell surface.
CONCLUSIONS
EGFR and DEP-1 physically interact at the cell surface and maintain bidirectional enzyme-substrate interactions, which are relevant to their respective oncogenic and tumor-suppressive functions. These observations highlight the emerging roles of vesicular trafficking in malignant processes.
Pubmed
Journal: Oncotarget
July/21/2016
Abstract
The efficient gene transfection, cellular uptake and targeted delivery in vivo are key issues for non-viral gene delivery vectors in cancer therapy. To solve these issues, we designed a new targeted gene delivery system based on epidermal growth factor receptor (EGFR) targeting strategy. An anti-EGFR monoclonal antibody h-R3 was introduced to dendriplexes of PAMAM and DNA via electrostatic interactions to form self-assembled h-R3-PAMAM-DNA complexes (h-R3-dendriplexes). Dendriplexes h-R3-dendriplexes represented excellent DNA encapsulation ability and formed unique nanostructures. Compared to dendriplexes, h-R3-dendriplexes presented lower cytotoxicity, higher gene transfection efficiency, excellent endosome escape ability and high nuclear accumulation in the EGFR-overexpressing HepG2 cells. Both ex vivo fluorescence imaging and confocal results of frozen section revealed that h-R3-dendriplexes showed higher targeted delivery and much better gene expression in the tumors than dendriplexes at the same N/P ratio, and h-R3-dendriplexes had accumulation primarily in the tumor and kidney. Moreover, h-R3-dendriplexes for p53 delivery indicated efficient cell growth inhibition and potentiated paclitaxel-induced cell death. These results indicate that the h-R3-dendriplexes represent a great potential to be used as efficient targeted gene delivery carriers in EGFR-overexpressing tumor cells.
Pubmed
Journal: Oncogene
April/19/1998
Abstract
Betacellulin (BTC) is a member of the EGF ligand family that directly binds to both EGFR and HER4 and induces the growth of certain epithelial cell types. Fusion proteins composed of the terminal 48 or 50 amino acids of mature betacellulin and a binding defective form of Pseudomonas exotoxin (BTC-TX48 and BTC-TX50, respectively), have been produced. BTC-TX50 induced tyrosine phosphorylation of both EGFR and HER4, whereas BTC-TX48 induced phosphorylation of HER4 but to a much lesser extent EGFR, indicating that the presence of two additional amino acid residues, Arg62 and Lys63, contribute to full kinase activity. BTC-TX50 was up to 300-fold more active at inhibiting protein synthesis than BTC-TX48 on cell lines expressing EGFR, most likely due to the >tenfold higher affinity of BTC-TX50. MDA-MB-453 breast carcinoma cells which express HER4 but not EGFR, were not sensitive to either BTC-TX form. These data indicate that despite the ability of BTC-TX to bind and phosphorylate HER4, it was only cytotoxic to cells expressing EGFR. The inability of BTC-TX to kill cells was likely due to its failure to internalize through HER4.
Pubmed
Journal: Cellular microbiology
September/25/2011
Abstract
Neisseria gonorrhoeae, the causative agent of the sexually transmitted infection gonorrhoea, adheres to and invades into genital epithelial cells. Here, we investigate host components that are used by the bacteria for their entry into epithelial cells. We found that gonococcal microcolony formation on the surface of HEC-1-B cells disrupted the polarized, basolateral distribution of both epidermal growth factor receptor (EGFR) and ErbB2, a related family member, and induced their accumulation under the microcolonies at the apical membrane. Gonococcal infection increased EGFR and ErbB2 phosphorylation. The EGFR kinase inhibitor, AG1478, reduced gonococcal invasion by 80%, but had no effect on adherence or the recruitment of EGFR and ErbB2 to the microcolonies. Gonococcal inoculation upregulated the mRNA levels of several ligands of EGFR. Prevention of EGFR ligand shedding by blocking matrix metalloproteinase activation reduced gonococcal invasion without altering their adherence, while the addition of the EGFR ligand, HB-EGF, was able to restore invasion to 66% of control levels. These data indicate that N. gonorrhoeae modulates the activity and cellular distribution of host EGFR, facilitating their invasion. EGFR activation does not appear to be due to direct gonococcal binding to EGFR, but instead by its transactivation by gonococcal induced increases in EGFR ligands.
Pubmed
Journal: Developmental biology
June/24/1996
Abstract
In Drosophila, neural precursor genes are expressed in neural progenitor cells as the neuroblasts and sense organ mother cells. These genes are thought to control the fate and/or behavior of neural progenitor cells once their fate decision has been made. We have isolated and characterized a novel neural precursor gene, inscuteable, whose expression is coincident with sites of cell shape changes or cell and tissue movement in the embryo, e.g., neuroblasts, trachea, Malphigian tubules, and in pupal wing epithelia. The Inscuteable protein is localized to the apical submembranous surface of neuroblasts and other cell types and shows certain features common to a family of putative cytoskeletal associated proteins. The inscuteable mutant phenotype, together with these other observations, suggests a possible role for the protein in cytoskeleton organization.
Pubmed
Journal: Developmental cell
December/4/2001
Abstract
Eyes absent (eya) encodes a member of a network of nuclear transcription factors that promotes eye development in both vertebrates and invertebrates. Despite extensive studies, the molecular mechanisms whereby cell-cell signaling pathways coordinate the function of this retinal determination gene network remain unknown. Here, we report that Drosophila Eya function is positively regulated by mitogen-activated protein kinase (MAPK)-mediated phosphorylation and that this regulation extends to developmental contexts independent of eye determination. In vivo genetic analyses, together with in vitro kinase assay results, demonstrate that Eya is a substrate for extracellular signal-regulated kinase, the MAPK acting downstream in the receptor tyrosine kinase (RTK) signaling pathway. Thus, phosphorylation of Eya appears to provide a direct regulatory link between the RTK/Ras/MAPK signaling cascade and the retinal determination gene network.
Pubmed
Journal: Cancer science
December/16/2008
Abstract
Anti-epidermal growth factor receptor (EGFR) monoclonal antibody, cetuximab, is a promising targeted drug for EGFR-expressing tumors. Glioblastomas frequently overexpress EGFR including not only the wild type but also a deletion mutant form called 'variant III (vIII)', which lacks exon 2-7, does not bind to ligands, and is constitutively activated. In this study, we investigated the antitumor activity of cetuximab against malignant glioma cells overexpressing EGFRvIII. For this purpose, we transfected human malignant glioma cell lines with the retroviral vector containing cDNA for EGFRvIII, and analyzed the mode of cetuximab-induced action on the EGFRvIII in the cells. Immunoprecipitation and immunofluorescence revealed binding of cetuximab to EGFRvIII. Notably, immunoblotting analyses showed that cetuximab treatment resulted in reduced expression levels of the EGFRvIII. However, cetuximab alone did not exhibit a growth-inhibitory effect against the EGFRvIII-expressing cells. On the other hand, an assay for antibody-dependent cell-mediated cytotoxicity (ADCC) demonstrated cetuximab-induced cytolysis in the presence of human peripheral blood mononuclear cells in a dose-dependent manner. These results suggest that deletion mutant EGFRvIII can be a target of cetuximab and that ADCC activity substantially contributes to the antitumor efficacy of cetuximab against the EGFRvIII-expressing glioma cells. Thus, cetuximab could be a promising therapy in malignant gliomas that express EGFRvIII.
Pubmed
Journal: Cancer science
May/15/2012
Abstract
The R521K polymorphism of epidermal growth factor receptor has attenuated affinity in ligand binding and proto-oncogene induction, which may affect the efficacy of cetuximab. We analyzed the effect of this polymorphism on the outcome of 112 patients with KRAS wild-type metastatic colorectal carcinoma treated with first-line cetuximab plus FOLFOX-4. The associations of this polymorphism with vascular endothelial growth factor (VEGF) expression and clinicopathologic characteristics were also examined. The results showed that the frequencies of the G/G, G/A, and A/A genotypes were 32.1% (n = 36), 42.9% (n = 48), and 25.0% (n = 28), respectively. A marked decrease in VEGF expression levels (66.7% vs 28.9%, P < 0.01) was observed in patients with 521A allele variants (Arg/Lys or Lys/Lys), which were associated with a decreased tumor size (55.6% vs 31.6%, P = 0.02), good histological differentiation (63.9% vs 85.5%, P = 0.01), decreased lymphovascular invasion (69.4% vs 39.5%, P < 0.01), and a higher response rate to cetuximab plus FOLFOX treatment (55.6% vs 78.9%, P = 0.01). In addition, this polymorphism was associated with a longer progression-free period (P = 0.001) and overall survival (P = 0.001). By multivariate analysis, this polymorphism was also identified as an independent prognostic factor. These data suggest that the R521K polymorphism of epidermal growth factor receptor, by reducing its activation and a consequential downregulation of its target genes, including VEGF, could be a key determinant of an increased response to cetuximab-based chemotherapy and a longer survival for KRAS wild-type colorectal carcinoma patients.
Pubmed
Journal: FEBS letters
November/26/2007
Abstract
Suppressor of T-cell receptor signalling 1 and 2 (Sts-1 and 2) negatively regulate the endocytosis of receptor tyrosine kinases. The UBA domain of Sts-2 and SH3-dependent Cbl-binding are required for this function. Sts-1 and -2 also possess a PGM domain, which was recently reported to exhibit tyrosine phosphatase activity. Here, we demonstrate that the PGM of Sts-1, but not of Sts-2, dephosphorylates the EGFR at multiple tyrosines thereby terminating its signalling and endocytosis. In contrast to Sts-2 the UBA of Sts-1 did not contribute significantly to receptor stabilization. Thus, although Sts-1 and Sts-2 are structurally highly homologous and both inhibit ligand-induced EGFR degradation, their mechanisms of action differ significantly. As a consequence, Sts-1-containing receptor complexes are inactive, whereas Sts-2-containing complexes are signalling competent.
Pubmed
Journal: Development (Cambridge, England)
October/13/1998
Abstract
The segmented portion of the Drosophila embryonic central nervous system develops from a bilaterally symmetrical, segmentally reiterated array of 30 unique neural stem cells, called neuroblasts. The first 15 neuroblasts form about 30-60 minutes after gastrulation in two sequential waves of neuroblast segregation and are arranged in three dorsoventral columns and four anteroposterior rows per hemisegment. Each neuroblast acquires a unique identity, based on gene expression and the unique and nearly invariant cell lineage it produces. Recent experiments indicate that the segmentation genes specify neuroblast identity along the AP axis. However, little is known as to the control of neuroblast identity along the DV axis. Here, I show that the Drosophila EGF receptor (encoded by the DER gene) promotes the formation, patterning and individual fate specification of early forming neuroblasts along the DV axis. Specifically, I use molecular markers that identify particular neuroectodermal domains, all neuroblasts or individual neuroblasts, to show that in DER mutant embryos (1) intermediate column neuroblasts do not form, (2) medial column neuroblasts often acquire identities inappropriate for their position, while (3) lateral neuroblasts develop normally. Furthermore, I show that active DER signaling occurs in the regions from which the medial and intermediate neuroblasts will later delaminate. In addition, I demonstrate that the concomitant loss of rhomboid and vein yield CNS phenotypes indistinguishable from DER mutant embryos, even though loss of either gene alone yields minor CNS phenotypes. These results demonstrate that DER plays a critical role during neuroblast formation, patterning and specification along the DV axis within the developing Drosophila embryonic CNS.
Authors
Pubmed
Journal: Biochimica et biophysica acta
September/13/2007
Abstract
ErbB receptors are important regulators of fetal organ development, including the fetal lung. They exhibit diversity in signaling potential, acting through homo- and heterodimers to cause different biological responses. We hypothesized that ErbB receptors show cell-specific and stimuli-specific activation, heterodimerization, and cellular localization patterns in fetal lung. We investigated this using immunoblotting, co-immunoprecipitation, and confocal microscopy in primary isolated E19 fetal rat lung fibroblasts and epithelial type II cells, stimulated with epidermal growth factor, transforming growth factor alpha, neuregulin 1beta, or treated with conditioned medium (CM) from the respective other cell type. Fetal type II cells expressed significantly more ErbB1, ErbB2, and ErbB3 protein than fibroblasts. ErbB4 was consistently identified by co-immunoprecipitation of all other ErbB receptors in both cell types independent of the treatments. Downregulation of ErbB4 in fibroblasts initiated cell-cell communication that stimulated surfactant phospholipid synthesis in type II cells. Confocal microscopy in type II cells revealed nuclear localization of all receptors, most prominently for ErbB4. Neuregulin treatment resulted in relocation to the extra-nuclear cytoplasmic region, which was distinct from fibroblast CM treatment which led to nuclear localization of ErbB4 and ErbB2, inducing co-localization of both receptors. We speculate that ErbB4 plays a prominent role in fetal lung mesenchyme-epithelial communication.
Pubmed
Journal: Acta haematologica
June/1/2014
Pubmed
Journal: Endocrine
January/30/2006
Abstract
Although porcine uterus is known to contain active and inactive forms of epidermal growth factor receptor (EGF-R), the latter consist of the extracellular domain only; it is currently unknown whether different EGF-R isoforms are expressed in the porcine oviduct during estrous cycle. Therefore, we used two different monoclonal antibodies, one against the extracellular and the other against the cytoplasmic domain of the EGF-R, to investigate cycle-dependent and cell-type-specific expression of full-size and truncated receptor forms. At metestrus, the majority of epithelial cells of the oviduct were strongly immunopositive for both antibodies, indicating the presence of the full-size receptor. In diestrous and proestrous stages, we found a low level of cytoplasmic but no extracellular EGF-R staining in epithelial cells. While the staining intensity of cytoplasmic domain of the EGF-R was only faint or absent in muscular tissue and blood vessels throughout the estrous cycle, extracellular domain of the EGF-R exhibited a strong immunostaining of smooth muscle cells and vascular smooth muscle cells, especially in diestrous and proestrous stages. There was no significant difference between the oviductal ampulla and isthmus in either the intensity or the pattern of both cytoplasmic and extracellular EGF-R immunostaining. We conclude that the restricted presence of the functional full-size receptor to the epithelial layer indicates a specific role during early embryonic development, whereas truncated EGF-R forms may potentially regulate contractions and blood flow in the oviduct.
Pubmed
Journal: Nan fang yi ke da xue xue bao = Journal of Southern Medical University
May/19/2013
Abstract
OBJECTIVE
To evaluate the effect of epidermal growth factor receptor tyrosine kinase inhibitor, gefitinib, on the expression of α-smooth muscle actin (α-SMA) in mice with lung fibrosis induced by bleomycin.
METHODS
Thirty male BALB/c mice were randomly divided into control, bleomycin, and bleomycin plus gefitinib groups. The mice in the control group were subjected to intratracheal administration of normal saline, those in bleomycin group received bleomycin (3 mg/kg) intratracheally, and those in bleomycin plus gefitinib group received oral gefitinib (20 mg/kg administering) plus intratracheal bleomycin administration. All the mice were sacrificed 14 days after the treatments, and the left lung was examined pathologically with HE staining and Masson staining and also immunohistochemically for assay of the total EGFR, phosphorylated EGFR and α-SMA. The right lungs were sampled for RT-PCR to detect the mRNA levels of α-SMA.
RESULTS
Gefitinib administration lessened lung fibrosis induced by bleomycin and significantly reduced lung collagen accumulation. The phosphorylation of EGFR in the pulmonary mesenchymal cells and epithelial cells and the expression levels of α-SMA mRNA and protein were inhibited by gefitinib treatment in mice with intratracheal administration of bleomycin (P<0.05).
CONCLUSIONS
Gefitinib offers protection against lung fibrosis induced by bleomycin in mice probably by inhibiting the downstream signals of EGFR and by downregulating the expression of α-SMA.
Pubmed
Journal: Anticancer research
October/10/2018
Abstract
OBJECTIVE
Epidermal growth factor receptor (EGFR), mothers against decapentaplegic homolog 7 (SMAD7) and transforming growth factor betta (TGFB) are crucial for colorectal cancer (CRC) tumorigenesis. This study investigated whether polymorphisms in EGFR, SMAD7, and TGFB are associated with CRC risk in patients with Lynch syndrome.
METHODS
Genotyping was performed using Sequenom iPLEX MassArray. Association between genetic polymorphisms and CRC was assessed using a weighted Cox proportional hazard model.
RESULTS
Patients carrying the AA genotype of EGFR rs2227983 had a significantly higher CRC risk than those carrying the G allele (HR=2.55, 95% CI=1.25-5.17). The dominant model of SMAD7 rs12953717 (CT + TT genotypes) significantly increased CRC risk (HR=2.17, 95% CI=1.12-4.16) when compared to the wild-type CC genotype. Similarly, the GG genotype of TGFBR2 rs6785358 significantly increased the risk of CRC (HR=21.1, 95% CI=5.06-88.1) compared to the AA genotype.
CONCLUSIONS
EGFR, SMAD7, and TGFBR2 are associated with CRC risk in patients with Lynch syndrome.
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