Epidermal Growth Factor Receptor Gene Expression Research Articles

Clinical Significance of Insulin-Like Growth Factor Type 1 Receptor and Epidermal Growth Factor Receptor in Patients with Advanced Gastric Cancer

Objective: To better understand the clinical implications of insulin-like growth factor type 1 receptor (IGF-1R), epidermal growth factor receptor (EGFR) and HER2 expressions in gastric cancer (GC). Methods: The study group comprised 86 patients who received first-line chemotherapy for advanced GC at the National Cancer Center Hospital. Using laser-captured microdissection and a real-time RT-PCR assay, we quantitatively evaluated mRNA levels of IGF-1R, EGFR and HER2 in paraffin-embedded cancer specimens of surgically removed primary tumors. Results: In univariate analysis of the study group as a whole, patients with low expression of both IGF-1R and EGFR (n = 13) had a significantly longer overall survival than the other patients (n = 51; median, 24.6 vs. 12.8 months; log-rank p = 0.013). Multivariate survival analysis demonstrated that high EGFR expression [hazard ratio, HR: 2.94 (95% confidence interval, CI: 1.40–6.17), p = 0.004] and poor performance status [HR: 1.96 (95% CI: 1.12–3.42), p = 0.018] were significant predictors of poor survival. In patients given first-line S-1 monotherapy (n = 29), low IGF-1R (p = 0.002) and low EGFR (p = 0.035) gene expression correlated with a better response, without a significant prolongation of survival. Conclusion: Our data warrant further investigations on the strategy of co-targeting IGF-1R and EGFR in GC.

Epidermal growth factor receptor (EGFR) expression in prostatic adenocarcinoma after hormonal therapy: A fluorescence in situ hybridization and immunohistochemical analysis

The progression of normal prostatic epithelium to androgen-dependent cancer and, eventually, hormone-refractory prostate cancer is a complex process involving many different growth regulatory signals. Activation of epidermal growth factor receptor (EGFR) has been implicated in prostate cancer cell growth. This study was undertaken to investigate both amplification of EGFR gene by fluorescence in situ hybridization (FISH) and over-expression of EGFR by immunohistochemical staining in prostate tissue from 71 patients treated by hormonal therapy. EGFR gene amplification was present in 1 of 71 tumors, and polysomy of chromosome 7 was present in 24 of 71 tumors. Immunohistochemically, EGFR expression was demonstrable in 57 of 71 tumors. Membranous immunostaining for EGFR was observed in >75% of tumor cells in 11% of cases, in 51-75% of tumor cells in 20% of cases, in 26-50% of tumor cells in 21% of cases, in 11-25% of tumor cells in 21% of cases, and in 1-10% of tumor cells in 7% of cases. No immunostaining for EGFR was seen in 20% of cases. There was no correlation between EGFR protein expression and gene amplification. There was also no correlation between EGFR expression and clinicopathological characteristics or clinical outcome. We found that EGFR gene expression was detectable in 35% of this large series of hormone-treated prostate cancer, and that EGFR protein is frequently expressed in tissue from these patients. EGFR over-expression may serve as a reasonable target for therapeutic intervention in this otherwise difficult to treat subset of prostate cancer.

Biotinylation and methylation of histones play a role in regulation of genes associated with hydrogen peroxide induced oxidative stress

The expression of approximately 10,000 genes changed in response to oxidative stress by H2O2 in Caco‐2 cells. Three genes, epidermal growth factor receptor (EGFR), the oncogene homolog KRAS, and guanidinoacetate N‐methyltransferase (GAMT), which showed the highest fold‐change in their expressions, were chosen to evaluate whether chromatin remodeling events play a role in stress‐dependent gene regulation. Relative enrichment of two epigenetic markers, biotinylation of lysine 12 in histone H4 (K12BioH4) and dimethylation of lysine 9 in histone H3 (K9Me2H3) in the promoter regions of the above genes was quantified by ChIP assays. Increased expression of EGFR and KRAS in stressed cells was associated with decreased relative abundance of K9Me2H3, whereas decreased expression of GMAT was associated with increased relative abundance of K9Me2H3 in promoter regions. The relative abundance K12BioH4 decreased in promoter regions of all three genes in stressed cells regardless of their observed expression changes, probably due to low expression of holocarboxylase synthetase (HCS), the mediator of biotinylation. These results suggest that epigenetic events may play a role in the expression of EGFR, KRAS and GMAT genes in oxidatively stressed cells. Support: Univ. of Nebraska ARD, Hatch Act, and NIH DK063945 and ES015206, USDA 2006‐35200‐17138, and NSF EPSCoR EPS‐0701892.

Involvement of EGFR in the response of squamous cell carcinoma of the head and neck cell lines to gefitinib

Epidermal growth factor receptor (EGFR) gene mutations are associated with the sensitivity of non-small cell lung carcinomas (NSCLCs) to gefitinib, but such findings have not been reported in squamous cell carcinomas of the head and heck (SCCHNs). Accordingly, we determined whether EGFR gene expression and mutations correlate with the in vitro efficacy of gefitinib in SCCHN cell lines. EGFR status was analyzed in 16 different SCCHN cell lines by polymerase chain reaction (PCR) and direct sequencing for activating mutations, by real-time quantitative RT-PCR, and by Western blot analysis for RNA and protein expression. Using direct sequencing of PCR products from exons 18-23 of 9 SCCHN cell lines, we found a heterozygous EGFR mutation (EGFRmut) with a 2607Gright curved arrow A transition in exon 20 (G/A genotype). The 9 different cell lines that showed this mutation also showed higher sensitivity (lower IC50 values) to gefitinib than cell lines with wild-type EGFR (EGFRwt: G/G genotype) (p=0.016). EGFR protein levels correlated robustly (r=0.76) and significantly (p=0.0007) with EGFR mRNA levels and with IC50 values for gefitinib (r=0.65, p=0.0067). EGFR mRNA correlated with IC50 values (r=0.67, p=0.0046). Our conclusion was that the heterozygous and synonymous transition of the EGFR gene and low EGFR expression levels of mRNA and protein in SCCHN may be reliable predictors of high sensitivity in SCCHN patients to gefitinib.

Leptin stimulates the proliferation of human oesophageal adenocarcinoma cells via HB-EGF and TGFα mediated transactivation of the epidermal growth factor receptor

Obesity increases the risk of developing oesophageal adenocarcinoma (OAC) as well as several other cancers. Leptin is secreted by adipocytes and serum leptin levels rise with body mass index. Leptin stimulates proliferation and inhibits apoptosis in OAC cells but the mechanisms are not fully elucidated, Transactivation of the epidermal growth factor receptor (EGFR) is an important signalling mechanism for G-protein-coupled receptors, but the relationship with leptin-type receptors has not been examined and the authors hypothesise that leptin-induced proliferation involves EGFR signalling. This study examines the effect of leptin on EGFR signalling in cultured cell lines. Leptin stimulated proliferation in four OAC lines expressing leptin receptors (OE33, OE19, BIC-1 and FLO) and this was abolished by specific EGFR inhibitors (PD153035 and AG1478). Leptin-induced proliferation was inhibited by neutralising antibodies to transforming growth factor-α (TGFα and HB-EGF) but not by anti-amphiregulin. Leptin significantly increased gene expression of HB-EGF and TGFα as measured by a quantitative real-time polymerase chain reaction (PCR) method but did not alter amphiregulin and EGFR gene expression. Leptin increased extracellular release of HB-EGF and TGFα and this was blocked by matrix metalloproteinase (MMP) inhibitors. The MMP inhibitors also abolished leptin-induced proliferation as well as leptin-induced EGFR tyrosine phosphorylation, but did not affect proliferation or EGFR activation induced by TGFα. The authors conclude that leptin stimulates OAC proliferation via increased gene expression of HB-EGF and TGFα, MMP-mediated extracellular release of HB-EGF and TGFα and subsequent activation of EGFR.

Association of EGFR c.2073A>T polymorphism with decreased risk of diffusely infiltrating astrocytoma in a Brazilian case-control study

Epidermal growth factor receptor (EGFR) gene overexpression has been implicated in the development of many types of tumors, including glioblastomas, the most frequent diffusely infiltrating astrocytomas. However, little is known about the influence of the polymorphisms of EGFR on EGFR production and/or activity, possibly modulating the susceptibility to astrocytomas. This study aimed to examine the association of two EGFR promoter polymorphisms (c.-191C>A and c.-216G>T) and the c.2073A>T polymorphism located in exon 16 with susceptibility to astrocytomas, EGFR gene expression and survival in a case-control study of 193 astrocytoma patients and 200 cancer-free controls. We found that the variant TT genotype of the EGFR c.2073A>T polymorphism was associated with a significantly decreased risk of astrocytoma when compared with the AA genotype [sex- and age-adjusted odds ratio 0.51, 95% confidence interval 0.26-0.98]. No association of the two promoter EGFR polymorphisms (or combinations of these polymorphisms) and risk of astrocytomas, EGFR expression or survival was found. Our findings suggest that modulation of the EGFR c.2073A>T polymorphism could play a role in future therapeutic approaches to astrocytoma.

Molecular Predictors of EGFR-TKI Sensitivity in Advanced Non–small Cell Lung Cancer

The epidermal growth factor receptor (EGFR) is overexpressed in the majority of non-small cell lung cancers (NSCLC) and is a major target for new therapies. Specific EGFR tyrosine kinase inhibitors (TKIs) have been developed and used for the treatment of advanced NSCLC. The clinical response, however, varies dramatically among different patient cohorts. Females, East Asians, non-smokers, and patients with adenocarcinoma usually show higher response rates. Meanwhile, a number of biological factors are also associated with EGFR-TKIs responsiveness. In order to better understand the predictive value of these biomarkers and their significance in clinical application we prepared this brief review. Here we mainly focused on EGFR somatic mutations, MET amplification, K-ras mutations, EGFRvIII mutation, EGFR gene dosage and expression, HER2 gene dosage and expression, and Akt phosphorylation. We think EGFR somatic mutation probably is the most effective molecular predictor for EGFR-TKIs responsiveness and efficacy. Mutation screening test can provide the most direct and valuable guidance for clinicians to make decision on EGFR-TKIs therapy.

Relationship ofEGFRMutations, Expression, Amplification, and Polymorphisms to Epidermal Growth Factor Receptor Inhibitors in the NCI60 Cell Lines

The mechanism of sensitivity and resistance to epidermal growth factor receptor (EGFR) inhibitors is incompletely understood, particularly in cancers other than non-small-cell lung cancer (NSCLC). To understand the variable response to this class of drugs, we used the NCI60 cancer cell lines. We aimed to determine if there are interactions between EGFR expression, mutations, polymorphisms, and gene amplification, and whether these factors are associated with variability in response to EGFR inhibitors. The EGFRVIII and tyrosine kinase (TK) domain mutations were examined in the NCI60 cancer cell lines. Five polymorphisms, -216G/T, -191C/A, intron 1 (CA)n, R497K, and 2607A/G, were genotyped. EGFR amplification was also assessed with high-density single-nucleotide polymorphism chip and real-time PCR, respectively. The results were correlated with cytotoxicity data for erlotinib and other 11 EGFR inhibitors, as well as other publicly available data for these lines. All 12 inhibitors behaved similarly. No EGFRVIII but putative TK mutations in two cell lines were found. Both mutant cell lines were insensitive to all inhibitors. Meanwhile, response did not correlate with EGFR amplification but with EGFR gene expression, especially in the cell lines with relatively normal gene status. In addition, EGFR expression was associated with the -216G/T polymorphism but not with the intron 1 (CA)n polymorphism. A combination of -216G/T and R497K polymorphisms was weakly associated with drug response. These observations suggest that in addition to TK mutations, germ-line variability may also contribute to the pharmacodynamics of EGFR inhibitors, particularly when EGFR is genetically normal.

Gene Expression Profiles as Markers of Aggressive Disease—EGFR as a Factor

We previously reported that 43 (58%) of 75 head and neck squamous cell carcinoma (HNSCC) tumors harbor increased epidermal growth factor receptor (EGFR) gene copy numbers as determined by fluorescent in situ hybridization. In this study, an increased EGFR copy number was associated with decreased progression-free survival and overall survival of HNSCC patients. However, activated EGFR protein levels are difficult to quantify by immunohistochemistry and are subject to dynamic regulation, specifically receptor downregulation on ligand binding. Therefore, we generated an activated EGFR gene expression signature in an in vitro HaCaT keratinocyte model system to further study genes involved in the EGFR signaling pathway in HNSCC. The results from this model system have suggested that the activated EGFR signature might reflect the activated state of the EGFR pathway in human HNSCC tumors and that it is associated with the increased EGFR gene copy number by fluorescent in situ hybridization. Furthermore, the activated EGFR signature has provided additional leads, because they are related to co-regulated molecular pathways and associated gene products on activation of EGFR. These could be exploited to refine and optimize combination therapies to be used in conjunction with available EGFR inhibitors in individual HNSCC patients.

Epidermal growth factor receptor (EGFR) mRNA expression levels are strongly correlated between primary colorectal cancer and corresponding liver metastases

4106 Background: As it has been well known that epidermal growth factor receptor (EGFR) is strongly related to a tumor proliferation and a metastasis, new EGFR-inhibitory small molecules, such as gefitinib and erlotinib, and EGFR antibodies have been developed recently. It is reported that the high expression levels of EGFR mRNA are associated with high response probability and longer progression-free survival in gefitinib-treated lung cancer patients. Thus, since liver metastases are the main cause of death for most of colorectal cancer (CRC) patients, it is reasonable to expect that measurement of EGFR gene expression levels in liver metastases would provide the best prediction of therapy benefit, but in most cases, only biopsies of the patient’s primary tumor are readily available for analysis. Our aim was to determine how EGFR gene expression levels in primary CRC were related to those in liver metastases. Methods: Thirty-one pairs of primary CRC and corresponding liver metastases were analyzed. (18 males and 13 females: Median age 66 (range 45–85)). Formalin-fixed, paraffin-embedded tumor specimens were dissected by using laser-captured microdissection. RNA was extracted and cDNA was prepared by reverse-transcription. Quantitation of target gene and internal reference gene was performed using real-time PCR (Taqman PCR). Results: No significant difference was seen between median mRNA expression levels of EGFR in primary cancer and those in corresponding liver metastases (Median value: 1.35 vs 1.24, p=0.99 , Wilcoxon signed rank test), although the median value of EGFR mRNA from normal liver tissue is significantly higher than those from normal colon mucosa (Median value: 5.06 vs 1.39, p<0.0001). When matched tissue sets were compared on an individual basis, there was a significant correlation for EGFR mRNA expression between primary cancer and corresponding liver metastases (rs=0.78, p<0.0001, Spearman rank correlation coefficient). Conclusions: A good prediction of EGFR mRNA levels in liver metastases can be obtained by measuring those of primary CRC. No significant financial relationships to disclose.

Amplifications of EGFR gene and protein expression of EGFR, Her-2/neu, c-kit, and androgen receptor in phyllodes tumor of the prostate

AbstractPhyllodes tumor of the prostate is a rare neoplasm with an unpredictable clinical behavior. It may undergo early recurrence with sarcomatous transformation or may even metastasize. Because targeted therapies have shown great success against several malignancies, there is hope that these same therapies may show similar promise in the treatment of other neoplasms. This study was undertaken to investigate both amplification of the epidermal growth factor receptor (EGFR) gene by fluorescence in situ hybridization and the overexpression of EGFR, Her-2/neu, CD117 (c-kit), and androgen receptor by immunohistochemical staining in a series of 11 phyllodes tumors of the prostate. In the stromal elements, EGFR gene amplification was present in four of 11 tumors and polysomy chromosome 7 was present in two of 11 tumors. No amplification was present in the epithelial components. Only one of 11 tumors had polysomy of chromosome 7 in the epithelial components. Immunohistochemically, in the stromal components, EGFR expression was demonstrable in four of 11 tumors and androgen receptor was demonstrated in six of 10 tumors. Neither Her-2/neu nor c-kit expression was seen in the stromal components of any of the 11 tumors. In the epithelial components, EGFR expression was present in all 11 tumors with strong staining in the basal cell layers and weak or no staining in luminal epithelium; androgen receptor expression was seen in seven of 10 tumors; Her-2/neu was weakly positive in four of 11 tumors; and c-kit expression was present focally and weakly in two of 11 cases with only 2–5% of cells staining. The highest staining intensity and the highest percentage of positively staining cells were seen with EGFR immunostaining in both the stromal and epithelial (mainly basal cells) components. Androgen receptor staining showed the next highest staining intensity and percentage of positive cells in both components. Her-2/neu and c-kit were only weakly or infrequently expressed in the epithelial components of prostatic phyllodes tumors. Our data indicate that EGFR and androgen receptor are frequently and strongly expressed in both epithelial and stromal components of prostatic phyllodes tumors. EGFR gene amplification is frequently present in prostatic phyllodes tumors and may account for one of the mechanisms leading to protein overexpression in some but not all cases. Anti-EGFR and/or antiandrogen agents may be potentially useful for management of patients with tumors expressing EGFR and/or androgen receptor.

Molecular classification of tumors with special reference to EGFR mutation in lung cancer

Unsupervised hierarchical clustering in expression profiling analyses allows molecular classification of tumors based on the similarity of genome-wide expression patterns. This new molecular-based classification shares the current pathological classification in part, although it also provides additional clues to identify cancers by their biological groups. Herein, we introduce a novel means of molecular classification of lung cancer. When examining the gene expression profiling analyses of lung cancers published so far, the molecular classification differs from the current classification schema, dividing lung cancers into two distinct branches that do not segregate SCLC and NSCLC, as might be expected. One of the branches includes adenocarcinoma alone, which is associated with a normal expression profile, while the other branch includes all four histological subtypes. We further examined the adenocarcinoma subset of the first branch. This subset of adenocarcinomas is characterized by frequent development in females and non-smokers, expression of thyroid transcription factor-1 and surfactant proteins, and specific involvement of epidermal growth factor receptor (EGFR) gene mutation. Furthermore, this subset is highly distinctive not only among lung cancers but also among carcinoma arising in other tissue sites, in terms of EGFR gene mutation and expression profiles. Although further studies are needed to clarify this adenocarcinoma subset, the distinction should be taken into consideration in lung cancer research and clinical strategies for treatment.

Gene Expression Levels of Epidermal Growth Factor Receptor, Survivin, and Vascular Endothelial Growth Factor as Molecular Markers of Lymph Node Involvement in Patients with Locally Advanced Rectal Cancer

Background Patients diagnosed with locally advanced rectal cancer usually receive surgical resection and adjuvant chemoradiation therapy. Lymph node involvement is an important clinical prognostic factor affecting recurrence and survival. Few studies have explored molecular markers associated with lymph node involvement of rectal cancer. Patients and Methods Tissue was obtained from 59 patients with locally advanced rectal cancer who were treated with adjuvant chemoradiation therapy. We assessed messenger RNA (mRNA) levels of genes involved in pathways of angiogenesis (vascular endothelial growth factor [ VEGF], cyclooxygenase-2), apoptosis (survivin), tumor growth and epidermal growth factor receptor ( EGFR), DNA repair ( ERCC1, Rad51), and the DNA synthesis in tumor tissue and tumor-adjacent normal tissue from paraffin-embedded samples using laser-capture microdissection methods. Results Twenty-four patients had no involvement of regional lymph nodes and 35 had lymph node metastases. In univariate analysis, patients with lymph node involvement had higher mRNA levels of VEGF and survivin in tumor tissue and EGFR in tumor-adjacent normal tissue compared with patients with no lymph node involvement ( P < 0.1; t test). Multivariate analysis using recursive partitioning showed that mRNA levels of EGFR, survivin, and Rad51 are primarily responsible for delineating node positive from node negative. Conclusion Gene expression of VEGF, survivin, and EGFR could be associated with lymph node involvement in patients with locally advanced rectal cancer. Further independent studies of those gene expression levels and lymph node involvement are warranted to better characterize the associations.

Epidermal Growth Factor Receptor and Epidermal Growth Factor Receptor Variant III Gene Expression in Metastatic Colorectal Cancer

The epidermal growth factor receptor (EGFR) variant type III (variously called EGFRvIII, de2-7 EGFR, or triangle upEGFR) has an in-frame deletion of the extracellular domain and is found in numerous types of human tumors. Because EGFRvIII has been reported to be tumor specific and has oncogenic potential, it is being investigated as a potential therapeutic target, but to our knowledge, there is only 1 previous report about EGFRvIII by immunohistochemistry in colorectal cancer. Our aim was to indicate the frequency of gene expressions of EGFRvIII and EGFR in metastatic colorectal cancer (mCRC). Forty-five patients with mCRC who received the chemotherapy for metastatic disease were analyzed for the EGFRvIII variant. Paraffin-embedded tumor tissues were dissected using laser-captured microdissection and analyzed for the EGFR and EGFRvIII messenger RNA expression using a quantitative real-time reverse-transcriptase polymerase chain reaction method. Gene expression values (relative messenger RNA levels) are expressed as ratios (differences from the cycle threshold values) between the target gene and internal reference gene (beta-actin). Twenty-five women and 20 men with a median age of 55 years (range, 25-76 years) were included in this study. We did not find any expression of EGFRvIII in these 45 patients except for control cell lines as U87.EGFRvIII. However, EGFR gene expression was found in 43 of 45 (95.6%) with a range of 0.38-2.83. Our results demonstrate that the expression of EGFRvIII is rare, but most colon cancer demonstrates EGFR gene expression. We conclude that EGFRvIII does not play an important role in mCRC.

ERCC1 and RRM1 but not EGFR gene expression is predictive of shorter survival in advanced non-small cell lung cancer (NSCLC)

10030 Background: Pivotal studies indicate a role of excision repair cross-complementation 1 (ERCC1) and ribonucleotide reductase M1 (RRM1) in conferring a differential sensitivity to cytotoxic chemotherapy and epidermal growth factor receptor (EGFR) has been recently deeply investigated in NSCLC. Methods: We retrospectively collected 70 formalin-fixed paraffin-embedded (FFPE) bronchoscopic/fine needle aspiration biopsies of NSCLC to investigate the expression levels of ERCC1, RRM1 and EGFR by Real-Time PCR (Lord R et al. Clin Cancer Research 2002, 8:2286–91). Results were correlated with survival using the Kaplan-Meier method. Results: Sixty-one (87%) specimens were successfully amplified. Median age was 62 years (range 26–75), male/ female ratio 44/17, stage III/IV 20/41; 43 patients received cisplatin-based chemotherapy; overall median survival (MS) was 13.3 months over a median follow-up time of 45 months. ERCC1 expression level ranged from 0.70 to 15.12, RRM1 0.60–17.82. By adopting cut-off values according to median expression levels, we found a strong correlation between ERCC1 and RRM1 mRNA levels (r=0.410; p&lt;0.001). MS in patients with low ERCC1 was significantly longer (16.9 vs 11.3 months, p&lt;0.006) as well as in patients with low RRM1 (13.9 vs 10.9 months, p&lt;0.03). Concomitant high expression levels of ERCC1 and RRM1 (n=26) are predictive of a worse outcome (13.9 vs 10.9 months, p&lt;0.05). Among patients treated with cisplatin-based regimens, low ERCC1 levels were also predictive of a significantly longer MS (23.0 vs 11.6 months, p&lt;0.002). A lower median ERCC1 level (3.2 vs 4.7) and a correlation with a better outcome were also observed in females vs males. No correlation between gene expression levels and histology was reported. No significant correlation between EGFR expression levels (range 0.5–85.8) and survival was found, even when different cut-off values were tested. Conclusions: This retrospective study further validates ERCC1 and RRM1 as good candidates genes to customize chemotherapy. Prospective studies based on the selection of patients according to genes expression levels are a research priority in early and advanced stages of NSCLC. [Table: see text]

The phyto-chemical (−)-epigallocatechin gallate suppresses gene expression of epidermal growth factor receptor in rat hepatic stellate cells in vitro by reducing the activity of Egr-1

Hepatic stellate cells (HSC) are the major effectors in hepatic fibrogenesis. During liver injury, HSC become activated and proliferative. Platelet-derived growth factor (PDGF) and epidermal growth factor (EGF) are the potent mitogens for many cell types. We previously demonstrated that (−)-epigallocatechin gallate (EGCG), the major and active component in green tea extracts, inhibited HSC growth, including reducing cell proliferation, and inducing apoptosis. We have reported that EGCG interrupts PDGF signaling by reducing receptor tyrosine phosphorylation and gene expression of PDGF-β receptor. Additional experiments are necessary to elucidate the effect of EGCG on EGF signaling in activated HSC. The aims of this study are to evaluate the effect of EGCG on the expression of EGFR and to elucidate the underlying molecular mechanisms in activated HSC. We hypothesize that EGCG might interrupt EGF signaling by suppressing gene expression of EGF receptor (EGFR) in activated HSC, which, together with the interruption of PDGF signaling, might collectively result in the inhibition of HSC growth. The present report demonstrates that the phyto-chemical dose-dependently suppresses gene expression of EGFR in activated HSC in vitro. The Egr-1 binding site located in the egfr promoter is found to be cis-activating element in regulating the promoter activity of the gene. EGCG inhibits the trans-activation activity of Egr-1 in activated HSC by suppressing gene expression of the transcription factor. The interruption of the ERK signaling pathway by EGCG reduces the trans-activation activity of Egr-1 and the promoter activity of EGFR gene in HSC. Taken together, our results demonstrate that EGCG suppresses gene expression of EGFR in rat activated HSC in vitro mediated by reducing the trans-activation activity of Egr-1.

Upregulation of the Expression of Epidermal Growth Factor and Its Receptor in Gingiva Upon Cyclosporin A Treatment

To understand the roles of epidermal growth factor (EGF) and EGF receptor (EGF-R) in cyclosporin A (CsA)-induced gingival overgrowth, expression of EGF and EGF-R upon CsA treatment was examined in an oral epidermoid carcinoma cell line of humans (OECM-1) and in edentulous gingiva of rats. In vitro study: after CsA treatment, OECM-1 cells were harvested to evaluate their mRNA and protein expression of EGF and EGF-R with reverse transcriptase-polymerase chain reaction (RT-PCR), Western blot, and immunocytochemistry (ICC). In vivo study: 3 weeks after extraction of all maxillary molars, 20 male Sprague-Dawley rats were assigned to a CsA group (30 mg/kg, fed daily) and a control group. Five rats per group were sacrificed at weeks 1 and 4. Edentulous ridge specimens were obtained for evaluating their mRNAs and protein expression with RT-PCR, real-time RT-PCR, and immunohistochemistry (IHC). In both in vitro and in vivo experiments, the proliferating potential of epithelial cells was examined by the presence of proliferating cell nuclear antigen (PCNA). In vitro: dose-dependently increased mRNA expression of EGF and EGF-R in OECM-1 cells was noted after CsA treatment. Protein expressions of EGF and EGF-R were higher in OECM-1 with CsA treatment than without CsA. In vivo: higher mRNA and protein expressions of EGF and EGF-R were also observed in the gingival tissues of CsA-treated rats. In both in vitro and in vivo experiments, greater PCNA expression after CsA treatment was demonstrated. Higher expression of EGF and EGF-R upon CsA therapy was observed in OECM-1 epithelial cells of humans and in edentulous gingiva of rats. We suggest that CsA could upregulate gene and protein expression of EGF and EGF-R, and the upregulation may play a role in gingival overgrowth.

Enhanced expression of epidermal growth factor receptor gene in gastric mucosal cells by the serum derived from rats treated with electroacupuncture at stomach meridian acupoints

To investigate the effect of serum derived from rats treated with electroacupuncture at stomach meridian acupoints on the expression of epidermal growth factor receptor (EGFR) gene in gastric mucosal cells. The stress-induced gastric mucosal injury in rat model was established by water-immersion and restrained stress methods. 52 rats were randomly divided into: normal group (n = 8), model group (n = 8), model serum group (n = 12), stomach serum group (n = 12), and gallbladder serum group (n = 12). The gastric mucosal cells were separated by pronase-EDTA digestion method and incubated with serum. The EGFR gene expression in gastric mucosal cells was detected by reverse transcription-polymerase chain reaction (RT-PCR) method. Compared with normal group (0.6860 +/- 0.0594), the serum derived from rats of the stomach group (1.2272 +/- 0.0813, P = 0.00 < 0.01) and gallbladder group (0.9640 +/- 0.0387, P = 0.00 < 0.01) had a tendency to enhance the EGFR gene expression in gastric mucosal cells. Such tendency existed in the model group (0.7104 +/- 0.0457) but with no significant difference (P = 0.495 > 0.05) and in model serum group (0.8516 +/- 0.0409) with an extremely obvious difference (P = 0.001 < 0.01). Furthermore, the EGFR gene expression in stomach serum group was significantly higher than that in gallbladder serum group (P = 0.00 < 0.01). The present study shows that serum derived from rats treated with electroacupuncture at stomach meridian acupoints can distinctly increase the EGFR gene expression of gastric mucosal cells. Therefore, there is certain meridian specificity in the serum, which could provide a proof for the TCM theory "particular relation between meridian and internal organ".

Gene expression of epidermal growth factor and epidermal growth factor receptor in oral lichen planus

To explore the expression of epidermal growth factor (EGF), epidermal growth factor receptor (EGFR), c-fos and c-jun in oral lichen planus (OLP). The levels of gene expression of EGF, EGFR, c-fos and c-jun were detected with reverse transcription-polymerase chain reaction (RT-PCR) in 10 cases of erosive OLP, 12 cases of reticular OLP and 9 cases of normal oral mucosa. Protein contents and distribution of EGF, EGFR, C-fos and C-jun were examined with immunohistochemical technique in different tissues. The endogenous levels of EGFR mRNA and protein in erosive OLP were (55.9 +/- 23.1)% and (71.1 +/- 10.1)%, respectively, and significantly higher than those in reticular OLP and normal oral mucosa. The mRNA contents of c-fos and c-jun were significantly higher in erosive OLP than in normal oral mucosa. The positive cell rates of c-fos and c-jun protein in erosive OLP were 1.3 and 1.5 times of those in normal oral mucosa, respectively (P < 0.05). The probability of carcinomatous change of erosive OLP might be higher than that of reticular OLP, in which EGF and EGFR might play an important role.

Curcumin inhibits human colon cancer cell growth by suppressing gene expression of epidermal growth factor receptor through reducing the activity of the transcription factor Egr-1

High expression of epidermal growth factor receptor (EGFR) is found in a variety of solid tumors, including colorectal cancer. EGFR has been identified as a rational target for anticancer therapy. Curcumin, the yellow pigment of turmeric in curry, has received attention as a promising dietary supplement for cancer prevention and treatment. We recently reported that curcumin inhibited the growth of human colon cancer-derived Moser cells by suppressing gene expression of cyclinD1 and EGFR. The aim of the present study was to explore the molecular mechanisms underlying curcumin inhibition of gene expression of EGFR in colon cancer cells. The generality of the inhibitory effect of curcumin on gene expression of EGFR was verified in other human colon cancer-derived cell lines, including Caco-2 and HT-29 cells. Promoter deletion assays and site-directed mutageneses identified a binding site for the transcription factor early growth response-1 (Egr-1) in egfr promoter as a putative curcumin response element in regulating the promoter activity of the gene in Moser cells. Electrophoretic mobility shift assays demonstrated that curcumin significantly reduced the DNA-binding activity of the transcription factor Egr-1 to the curcumin response element. In addition, curcumin reduced the trans-activation activity of Egr-1 by suppressing egr-1 gene expression, which required interruption of the ERK signal pathway and reduction of the level of phosphorylation of Elk-1 and its activity. Taken together, our results demonstrated that curcumin inhibited human colon cancer cell growth by suppressing gene expression of EGFR through reducing the trans-activation activity of Egr-1. These results provided novel insights into the mechanisms of curcumin inhibition of colon cancer cell growth and potential therapeutic strategies for treatment of colon cancer.