Increased epidermal growth factor receptor gene expression by gamma-interferon in a human breast carcinoma cell line

The interferons are a group of naturally occurring proteins that inhibit the growth of tumours in vivo and many transformed cell lines in vitro. The mechanisms of action of interferon, however, remain unclear. The IFN induced inhibition of growth of many epithelial cancer cell lines is associated with changes in Epidermal Growth Factor Receptor (EGFR) binding or expression. Therefore, we examined the effect of IFN treatment on the expression of EGFR in a human breast carcinoma cell line, MDA 468. We have found the IFN-gamma inhibited, in a dose dependent fashion, the growth of MDA 468 cells. IFN decreased cell surface binding of 125I-EGF to EGFR by changing receptor number rather than affinity. However, total cellular receptor protein, as measured by immunoprecipitation with monoclonal antibodies, was increased in IFN-treated cells. The half-life of the metabolically labelled receptor was unchanged by treatment with IFN. Increased amounts of EGFR mRNA were observed in MDA 468 cells treated with IFN-gamma for 3 days. The levels of mRNA increased with time in culture, reaching a peak of four times control values after 5 days of treatment. This effect was observable with as little as 10 U ml-1 of IFN-gamma. Treatment of the cells with Actinomycin D to inhibit new RNA synthesis suggested that the stability of EGFR mRNA was not enhanced in IFN-gamma treated cells. The increase in receptor mRNA induced by IFN was not inhibited by cycloheximide. These data suggest IFN-gamma can increase expression of EGFR mRNA and protein in MDA 468 cells. Increased expression of EGFR mRNA and protein by IFN-gamma is associated with inhibition of cell growth.     

Modulation of epidermal growth factor receptor gene expression by transforming growth factor-beta in a human breast carcinoma cell line

Modulation of epidermal growth factor (EGF) receptor expression determines cellular responsiveness to EGF and might play an important role in growth inhibition. We have investigated the actions of EGF and/or transforming growth factor type beta (TGF beta) on EGF receptor gene expression in MDA-468 human breast carcinoma cell line, which responds to EGF and/or TGF beta with growth inhibition. Using the cDNA clone pE7, which encodes 2.4 kilobases of the human EGF receptor mRNA, as a hybridization probe, we have found that exposure of MDA-468 cells to EGF results in elevated levels of EGF receptor mRNA. This increase in mRNA accumulation showed time and dose dependence. Addition of TGF beta enhances the accumulation of EGF receptor mRNA induced by EGF. Under this condition, stimulation could be detected after 1 h exposure to TGF beta with a maximum at 6-8 h. A concentration of 10 pM TGF beta gave detectable stimulation with maximal stimulation occurring at 300 pM in the presence of EGF (50 ng/ml). In contrast, TGF beta alone had no significant effect on EGF receptor mRNA accumulation. In the presence of cycloheximide, the EGF receptor mRNA was super-induced in response to EGF. Treatment of the cells with TGF beta enhances the EGF-dependent superinduction of EGF receptor mRNA produced by cycloheximide, suggesting that the stimulatory action of TGF beta does not depend on continuous protein synthesis. The results described here are consistent with the hypothesis that the growth inhibitory action of TGF beta in MDA-468 cells may be mediated, at least in part, by modulation of EGF receptor gene expression.     

Amplification and overexpression of the epidermal growth factor receptor gene in human renal-cell carcinoma

We examined 22 cases of renal-cell carcinoma (RCC) for structural alterations of the epidermal growth factor receptor (EGFR) gene and found gene amplification in one case of high-stage-high-grade RCC. Dot blot analysis of the total RNA from tumorous and normal kidney tissues revealed overexpression of the EGFR gene in 12 of 20 (60%) cases of RCC. The highest expression was observed in the gene-amplified case. No correlation was observed between the level of EGFR mRNA and tumor stage or grade. Northern blot analysis revealed normal 10- and 5.6-kb EGFR mRNA bands in RCC. Our data indicate that gene amplification of the EGFR gene is one of the molecular mechanisms of its overexpression in a subset of RCCs.     

Amplification of epidermal growth factor receptor gene in renal cell carcinoma

Expression of epidermal growth factor receptor (EGFR) may be of prognostic value in renal cell cancer (RCC). Gene amplification of EGFR was investigated in a cohort of 315 patients with advanced RCC from a previously reported randomised study. Using fluorescent in situ hybridisation, only 2 patients (0.6%) had gene amplification; therefore gene amplification is of no prognostic value in RCC.     

Comparison of estrogen receptor and epidermal growth factor receptor content of primary and involved nodes in human breast cancer

Estrogen receptors (ER) and epidermal growth factor receptors (EGFR) in the tumor cells of breast cancer tissues (primary tumors) and metastatic lymph nodes (involved nodes) were analyzed by immunocytochemical study in 19 patients; 12 were ER positive, and seven were ER negative. Microscopic study was used to determine the percentage of positive cells and the staining index. The percentage of EGFR-positive cells and the EGFR staining index were higher in the ER-negative primary tumors than ER-positive primary tumors. In ER-positive cases, both the number of ER-positive cells and ER content per cell was less in the involved nodes than in the primary tumors, whereas the number of EGFR-positive cells and EGFR content per cell was greater in affected nodes. On the other hand, in the ER-negative cases the number of EGFR-positive cells and EGFR content per cell remain almost unchanged between the primary tumors and involved nodes. The authors supposed a probability, in this study, that estrogen may exert inhibitory action on EGFR production through binding to ER.     

Expression of epidermal growth factor receptor mRNA and protein in primary breast carcinomas

The expression of epidermal growth factor receptor (EGFR) mRNA and protein has been determined in a group of breast carcinomas and compared to oestrogen and progesterone receptor (ER, PgR) status, as well as pathological features. In situ hybridization using a digoxigenin-labelled oligonucleotide probe was applied to formalin-fixed paraffin-embedded sections, and immunohistochemistry was used to determine EGFR protein.EGFR mRNA was detected in 66% of carcinomas with a third having labelling similar to normal breast tissue, 22% heterogeneous weak to strong labelling, and 11% strong labelling. EGFR protein was detected in 36% and these tumours had a strong correlation to lack of ER and high histological grade. The presence of EGFR protein was strongly correlated with more intense labelling for EGFR mRNA (p < 0.0001). This contrasted with normal breast in which both EGFR protein and mRNA were present with varying degrees in both tumours and a normal breast control. The ER-/PgR- carcinomas showed the full range of EGFR mRNA labelling. It is postulated that oestrogen or oestrogen regulated proteins are involved in regulation of EGFR mRNA and protein. In a proportion of tumours lacking steroid receptors regulation is lost, leading to EGFR overexpression.     

Immunohistochemical study of epidermal growth factor and epidermal growth factor receptor in gastric carcinoma

Immunohistochemical study for epidermal growth factor (EGF) and epidermal growth factor receptor (EGFR) was performed on 222 specimens of gastric carcinoma. The authors placed each carcinoma into one of the following three groups: group 1, neither EGF nor EGFR was stained (123 cases); group 2, either EGF or EGFR was stained (64 cases); and group 3, both EGF and EGFR were stained (35 cases). Compared with the carcinomas in groups 1 and 2, those in group 3 had significantly higher rates of infiltrative gross type, microscopically infiltrative type, poorly differentiated type, scirrhous type, and deep invading type. These results suggest that carcinomas in group 3 may have more proliferative and invasive activity and thus may have an autocrine mechanism, that is, the ability of cancer cells to produce and respond to their own growth factor.     

Expression of epidermal growth factor receptor and transforming growth factor alpha in human larynx carcinoma.

Altered expression of growth factors and growth factor receptors is frequently described in human tumors and human tumor cell lines. This further supports the hypothesis that oncogenesis is due to the subversion of mitogen-responsive pathways. The aim of this study was to investigate the expression of epidermal growth factor receptor (EGFR) and transforming growth factor alpha (TGF alpha) in 13 larynx carcinomas and 2 carcinomas of the oral cavity. We found receptor overexpression in 7 out of 15 tumors at mRNA and/or protein level but low expression in the majority of the normal adjacent tissues. TGF alpha was expressed only in 1 case, but no tyrosine kinase activity of the receptor was detected by antiphosphotyrosine antibody.     

结直肠癌组织EGFR基因表达及其与临床意义的研究

目的：通过对结直肠癌上皮生长因子受体（epidermal growth factor receptor,EGFR）基因的表达及其在体细胞突变的研究,探讨EGFR基因的表达与临床病理特征的关系。方法：收集解放军总医院病理科2004～2006年手术治疗的675例结直肠癌患者的临床及病理资料,采用免疫组织化学法检测结直肠癌组织中EGFR基因的表达并探讨其与患者临床病理特征的关系。在上述病例中随机选取25例,其中5例经免疫组织化学染色显示EGFR表达呈强阳性,提取这25例石蜡组织DNA,进行PCR扩增并测序从而分析在结直肠癌中EGFR基因的突变情况。结果：免疫组化结果显示EGFR基因的阳性率为21．33％（144／675）。EGFR基因的表达与结直肠癌的肿瘤直径（Χ^2=0．0204,P=0。8836）、肠壁浸润深度（Χ^2=1．1286,P=0．2881）、淋巴结转移情况（Χ^2=0．0708,P=0．7902）及肿瘤的病理分期（Χ^2=5．3691,P=0．1467）无关,但与肿瘤的分化程度（Χ^2=5．7793,P=0．0162）、腹腔及远处转移情况（Χ^2=4．3983,P=0．0360）密切相关。25例结直肠癌中有1例显示EGFR基因存在错义突变,有5例显示同义突变。结论：EGFR基因的表达与结直肠癌的分化程度及远处转移有关,可辅助判断患者的预后和转移情况以及指导临床治疗。EGFR基因在结直肠癌的突变可能为低频率事件。     

Significance of epidermal growth factor receptor expression in primary human endometrial cancer

Radioreceptorial assessment of EGFR expression was prospectively performed on 60 primary human endometrial tumors. Of these, 26 were EGFR-positive while 13 expressed high EGFR levels. High EGFR levels correlated well with poor histopatho-logical grading. No correlation with histopathological type, stage, myometrial invasion, lymph-node involvement or steroid hormone receptor status was observed. Disease-free survival rate was significantly shorter in the cases with high than in the cases with low EGFR levels. These results suggest a potential role of EGFR expression assessment in prognostic characterization of endometrial cancer patients. © 1994 Wiley-Liss, Inc.     

The epidermal growth factor receptor as a target for therapy in breast carcinoma

Summary The epidermal growth factor (EGF) receptor and its ligands have an important regulatory role in breast carcinoma. We have produced a series of monoclonal antibodies (MAbs) directed against the external portion of the EGF receptor. These MAbs prevent the binding of the ligands to the receptor, block ligand-induced activation of the receptor, and can inhibit the growth of breast cancer cells both in tissue culture and in human tumor xenografts in nude mice. We have also shown that anti-EGF receptor antibodies greatly enhance the antitumor effects of chemotherapeutic agents active in breast cancer. Phase I clinical trials with single doses of MAb conducted in patients with tumors over-expressing EGF receptors demonstrated favorable pharmacokinetics, good tumor imaging, and a lack of toxicity. A human:murine chimeric antibody has been produced with comparable affinity and antitumor activity that will enable us to administer repeated doses of MAb either alone or in combination with chemotherapy. Our pre-clinical data support the concept that the EGF receptor may be an optimal target for treatment with receptor blocking antibodies, either alone or in combination with chemotherapy.     

Progestin regulation of epidermal growth factor receptor in human mammary carcinoma cells

Epidermal growth factor (EGF) receptors are present in human breast cancer and probably mediate the effects of EGF and the autocrine effects of alpha-transforming growth factors, produced by breast cancer cells. Steroid hormones influence the growth of some human cancers, and both direct and indirect effects on cell proliferation have been proposed. One potential indirect effect of steroids would be to augment sensitivity to other endocrine and autocrine factors by up-regulation of their receptors. We therefore investigated the effects of various steroids on EGF receptor expression in T-47D, MCF-7, and BT 20 human mammary carcinoma cells in culture. Preincubation of T-47D cells for 24 h with a series of androgens, estrogens, glucocorticoids, and progestins resulted in a significant enhancement of specific 125I-EGF binding in the presence of progestins only. Increased binding of EGF was associated with neither a change in cell number nor changes in the specific binding of concanavalin A, insulin, or calcitonin but was accompanied by an increase in lactogenic receptor expression. When assayed at 20 degrees C, increased EGF binding was due to an increase in receptor number (33,380 +/- 7,410 sites/cell in control cultures; 67,460 +/- 20,330 sites/cell in cultures treated with 1 nM medroxyprogesterone acetate for 24 h; P less than 0.05) without a change in receptor affinity. Two- to 3-fold increases in receptor number were also apparent when binding was measured at 4 degrees C, indicating that the effect was due to an increase in expression of receptor at the cell surface rather than progestin effects on internalization and degradation. These data illustrate that the expression of EGF receptor in some breast cancer cells is regulated in part by mechanisms mediated via the progesterone receptor, since the effect was confined to progestins, potency among a series of progestins was correlated with their affinities for progesterone receptor, and sensitivity among the three cell lines studied was related to the presence and concentration of cellular progesterone receptor.     

Gefitinib and epidermal growth factor receptor gene mutation

Epidermal growth factor receptor (EGFR) gene mutations are frequent in lung cancer of Asian ethnicity, female gender, non-smokers,and of adenocarcinoma histology. About 80% of the patients with EGFR mutations respond to EGFR tyrosine kinase inhibitor (TKI) including gefitinib and erlotinib, while only 10% of those without EGFR mutations do so. Therefore, EGFR mutation is being recognized as one of the most reliable predictive factors in gefitinib treatment. Another important issue in clinical practice is fatal interstitial lung disease (ILD) in patients with gefitinib treatment, especially for Asian patients. A nested case-control study recently conducted in Japan identified some risk factors which cause ILD. About half of the acquired resistance to gefitinib that almost always occurs during the course of gefitinib administration is reportedly caused by secondary mutation at codon 79 0 (T 79 0 M). EGFR-TKIs are not universally effective for lung cancer,but these drugs are effective in patients who have particular characteristics. Therefore, patients who would benefit from gefitinib therapy should be included in clinical trials. Based on this concept, phaseIII clinical trials comparing gefitinib monotherapy with standard platinum-based chemotherapy in lung cancer patients with EGFR mutations are ongoing.