Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “eGFR”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 343 records · Page 19Linked to original sources
PubMed2005

In vivo and in vitro antitumor activity of oxaliplatin in combination with cetuximab in human colorectal tumor cell lines expressing different level of EGFR.

This study aimed to assess the effect of cetuximab (C225, Erbitux, a chimeric anti-epidermal growth factor receptor (EGFR) monoclonal antibody) in combination with oxaliplatin in vitro and in vivo on four colon cancer cell lines (HCT-8; HT-29, SW620, HCT-116) expressing different levels of EGFR. In vitro, cetuximab combined with oxaliplatin significantly decreased the IC50 values of oxaliplatin in HCT-8 (EGF-R moderate) and HT-29 (EGF-R weak) cell lines, while SW620 (EGF-R negative) and HCT-116 (EGFR strong) cell lines remained unresponsive. This combination was synergistic in HCT-8 and HT-29 cell lines while cetuximab induced no major modification of the IC50 of oxaliplatin in HCT-116 or SW620 cell lines. We then determined the effect of cetuximab on the EGF-induced EGFR phosphorylation and we highlight a correlation between the basal level of phospho-EGFR and the response to the combination. In vivo, the combination of cetuximab plus oxaliplatin significantly inhibited tumor growth of HCT-8 and HT-29 (tumor delay or Td = 21.6+/-2.9 and 18.0+/-2.9 days respectively, synergistic effect) compared to either oxaliplatin (Td=12.6+/-2.3 and 14.4+/-3.2 days respectively) or cetuximab (Td=13.4+/-2.9 and 14.5+/-2.4 days, respectively) alone in xenograft models. The combination had no effect on HCT-116 and SW-620 cell lines. The observed responses are strictly dependent on the cell type, and are not correlated with the level of EGFR expression but related to the basal level of phospho-EGFR. This study provides promising preclinical results for a possible clinical investigation of the combination of oxaliplatin plus cetuximab in chemorefractory colorectal tumors.

Animals↗
PubMed2006

Mutation profile of EGFR gene detected by denaturing high-performance liquid chromatography in Japanese lung cancer patients.

PURPOSE: EGFR mutations in lung cancer increase sensitivity to an EGFR tyrosine kinase inhibitor, gefitinib. Mutation analysis of EGFR is essential for prediction of gefitinib response and avoidance of the coincidental severe side effects for the unresponsive population. The purpose of the present study is to apply DHPLC as a screening system of detection of EGFR mutations for large scaled population. METHODS: EGFR mutations were detected by both DHPLC procedure and direct sequencing using lung cancer tissue samples obtained from 97 patients (81 surgical specimens and 16 pleural effusions of non-resectable lung cancer patients). RESULTS: DHPLC analysis detected EGFR mutations in 5 h as opposed to 18 h by direct sequencing for ten samples, and it costs eightfold more expensive by direct sequencing than DHPLC. In addition, DHPLC analysis was sixfold more sensitive than sequencing analysis for detection of the point mutation of exon 21, L858R. Using this system, EGFR mutations in exons 18, 19 and 21 were found in 34 of 97 patients (36%). Thirteen of the 15 patients with exon 21 mutations (87%) were female non-smokers, who were diagnosed with adenocarcinomas with the feature of BAC. Eight of the 18 patients with exon 19 mutations (44%) were 7 male and 1 female current or former smokers, and BAC feature was observed in 61% (8/18). CONCLUSION: DHPLC analysis for screening followed by sequencing analysis appears to be more sensitive and accurate, as well as easier and faster. In addition, these results suggest different mutagenesis and carcinogenesis pathways for mutations.

Base Sequence↗
PubMed2006

Indole-3-carbinol-induced death in cancer cells involves EGFR downregulation and is exacerbated in a 3D environment.

Indole-3-carbinol (I3C) is a promising anticancer dietary compound, which inhibits breast cancer in animal models. The objective of the current study was to characterize I3C-induced cell death in a panel of human breast tumorigenic cells (MCF7, MDA-MB-468, MDA-MB-231 and HBL100) in comparison with normal fibroblasts. Since epithelial cells are protected from cell death by a three-dimensional environment, 3D cell culture (collagen I gel and spheroids) was employed to investigate susceptibility to I3C. Cell viability in the presence of 256 microM I3C, a concentration close to the physiologically achievable range, was in the order fibroblasts = HBL100>MDA-MB-231>MCF7>MDA-MB-468 in monolayer culture. However, 3D culture conditions increased the susceptibility of MCF7 and MDA-MB-468 cancer cells towards I3C. I3C induced cell death in breast cancer MCF7, MDA-MB-468 and MDA-MB-231 cells via the mitochondrial apoptotic pathway. I3C significantly reduced levels of epidermal growth factor receptor (EGFR) in MDA-MB-468 after 6 h and in MDA-MB-231 and HBL100 cells after 30 h. Downregulation of EGFR in MDA-MB468 and MDA-MB-231 cells using an EGFR inhibitor resulted in apoptosis. EGFR modulation using EGF or an EGFR inhibitor markedly influenced viability and response to I3C in MDA-MB-468 cells in 3D conditions. EGFR expression was modulated by 3D conditions. Therefore, I3C-induced EGFR reduction in these cells is likely to be responsible for I3C-induced apoptosis.

Adenosine Triphosphate↗
PubMed1994

Induction of tumour cell lysis by a bispecific antibody recognising epidermal growth factor receptor (EGFR) and CD3.

A bispecific antibody construct (bAb) recognising CD3 and epidermal growth factor receptor (EGFR) was studied in vitro. Human peripheral blood lymphocytes (PBL), pre-activated with monoclonal antibody OKT-3 or with irradiated tumour cells, were armed with the bAb construct and targeted to autologous and allogeneic tumour target cells in culture. bAb EGFR x CD3 promoted significant cytolysis even at a concentration of 1 ng/ml. The specificity of target cell lysis was provided by the EGFR specificity of the bAb, as tumour cells negative for EGFR were not lysed. However, not only EGFR-positive tumour cells but also EGFR-positive normal cells were killed. Human renal cancer cell lines and the normal autologous kidney cell cultures expressing the same level of EGFR molecules were lysed to a similar extent. These results may contribute toward the planning of future clinical trials with such bAb.

Antibodies, Bispecific↗
PubMed2006

The complexity of targeting EGFR signalling in cancer: from expression to turnover.

The epidermal growth factor receptor (ErbB1 or EGFR) has been found to be altered in a variety of human cancers. A number of agents targeting these receptors, including specific antibodies directed against the ligand-binding domain of the receptor and small molecules that inhibit kinase activity are either in clinical trials or are already approved for clinical treatment. However, identifying patients that are likely to respond to such treatments has been challenging. As a consequence, it still remains important to identify additional alterations of the tumor cell that contribute to the response to EGFR-targeted agents. While EGFR-mediated signalling pathways have been well established, there is still a rather limited understanding of how intracellular protein-protein interactions, ubiquitination, endocytosis and subsequent degradation of EGFR contribute to the determination of sensitivity to EGFR targeting agents and are emerging areas of investigation. This review primarily focuses on the basic signal transduction pathways mediated through activated membrane bound and/or endosomal EGFR and emphasizes the need to co-target additional proteins that function either upstream or downstream of EGFR to improve cancer therapy.

Animals↗
PubMed2006

EGFR intragenic loss and gene amplification in astrocytic gliomas.

We have studied EGFR gene amplification and allelic status of chromosome 7 in 68 tumors consisting of 34 WHO grade IV glioblastomas (26 primary and 8 secondary), 14 WHO grade III anaplastic astrocytomas, and 20 WHO grade II astrocytomas, by polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP), quantitative PCR, and microsatellite analysis. EGFR gene amplification was present in 27 of these tumors (40%), and we identified allelic losses at 7p11 approximately p14 in 38 of the 68 cases (56%), including 17 tumors displaying loss for EGFR intragenic markers. The positive correlation (P < 0.05, chi(2)) between tumors with EGFR intragenic loss and EGFR gene amplification, frequently displaying the EGFR vIII form, suggests that EGFR gene rearrangement leading to intragenic loss is a molecular event that participates in the amplification process of this gene.

Astrocytoma↗
PubMed2006

Mutational status of the epidermal growth factor receptor (EGFR) gene in thymomas and thymic carcinomas.

Epithelial tumours of the thymus (thymoma, thymic carcinoma) are rare tumours of the anterior mediastinum. Current treatment options of advanced stage thymomas and thymic carcinomas include a multimodal therapy with radio- and chemotherapy as well as surgery. In recent years, new therapeutic targets such as EGFR (epidermal growth factor receptor), COX-2 and KIT have emerged as new potential therapeutic targets. So far, EGFR mutational status of different subtypes of epithelial tumours of the thymus has been analyzed only inappropriately. We have investigated 20 different subtypes of thymomas (type A, AB, and B3) and thymic carcinomas for mutations in exons 18, 19, 20, and 21 of the EGFR gene and performed immunohistochemistry for EGFR. Concerning immunohistochemistry, most of the cases (17/20) had a strong positive staining. Although sequence alterations were found in four samples, none of these alterations led to amino acid changes in the tyrosine kinase domain of EGFR comparable to those in non-small cell lung cancer. Thus EGFR-expression in thymic tumours does not rely on mutations in critical functional (activation) domains of the EGFR-gene. Experimental and therapeutic approaches have to consider this difference.

Aged↗
PubMed2004

Effects of the EGFR/HER2 kinase inhibitor GW572016 on EGFR- and HER2-overexpressing breast cancer cell line proliferation, radiosensitization, and resistance.

PURPOSE: Two members of the epidermal growth factor receptor family, EGFR and HER2, have been implicated in radioresistance in breast cancer and other malignancies. To gauge the potential clinical utility of targeting both EGFR and HER2 to control growth and radiosensitize human breast cancers, we examined the effect of a dual EGFR/HER2 inhibitor, GW572016, on the proliferation and radiation response of either EGFR- or HER2-overexpressing human breast cancer cell lines. METHODS AND MATERIALS: Primary human breast cancer cell lines that endogenously overexpress EGFR or HER2 and luminal mammary epithelial H16N2 cells stably transfected with HER2 were evaluated for the effect of GW572016 on inhibition of ligand-induced or constitutive receptor phosphorylation, proliferation, radiosensitization, and inhibition of downstream signaling. RESULTS: GW572016 inhibited constitutive and/or ligand-induced EGFR or HER2 tyrosine phosphorylation of all five cell lines, which correlated with the antiproliferative response in all but one cell line. GW572016 radiosensitized EGFR-overexpressing cell lines, but HER2-overexpressing cells were unable to form colonies after brief exposure to GW572016 even in the absence of radiation, and thus could not be evaluated for radiosensitization. One cell line was resistant to the antiproliferative and radiosensitizing effects of GW572016, despite receptor inhibition. Exploration of potential mechanisms of resistance in SUM185 cells revealed failure of GW572016 to inhibit downstream ERK and Akt activation, despite inhibition of HER2 phosphorylation. In contrast, sensitive HER2-overexpressing cell lines demonstrated inhibition of both ERK and Akt phosphorylation. CONCLUSION: GW572016 potently inhibits receptor phosphorylation in either EGFR- or HER2-overexpressing cell lines and has both antiproliferative and radiosensitizing effects. Resistance to GW572016 was not due to a lack of receptor inhibition, but rather with a lack of inhibition of ERK and Akt, suggesting that measurement of inhibition of crucial signaling pathways may better predict response than inhibition of receptor phosphorylation. The SUM185 cell line provides a valuable model for studying mechanisms of resistance of EGFR/HER2 inhibitor therapy.

Breast Neoplasms↗
PubMed2004

Combining EGFR inhibitors with radiation or chemotherapy: will preclinical studies predict clinical results?

PURPOSE: To highlight some of the preclinical data that examine the interaction of epidermal growth factor receptor (EGFR) inhibitors with radiotherapy and chemotherapy. METHODS AND MATERIALS: Recognition of the EGFR as an important regulator of tumor cell growth in the early 1980s stimulated the development of a series of molecules specifically designed to inhibit EGFR signaling as anticancer agents. Many of these agents have now matured and are in advanced clinical trial investigations, with tumor response rates on the order of 10-20% identified across a variety of human malignancies. Initially designed primarily as "cytostatic" agents, as opposed to "cytotoxic" agents, it is possible that the EGFR inhibitors will realize their optimal clinical impact when delivered in concert with conventional cytotoxic modalities such as radiotherapy and/or chemotherapy. RESULTS: Despite very strong in vitro and in vivo preclinical results, several major gaps remain in our knowledge regarding the EGFR inhibitor mechanisms of interaction with radiotherapy and chemotherapy, with considerable selection bias in the publication of preclinical data available to date. CONCLUSION: By acknowledging the limitations of the available preclinical data and by expanding our mechanistic understanding of EGFR inhibitor function in representative tumor model systems, we should enhance our capacity to predict the most rational and successful methods to combine EGFR inhibitors with cytotoxic modalities in future clinical trials.

Antineoplastic Agents↗
PubMed2026

Integrated multi-omic profiling enables recurrence risk stratification beyond pathological stage in resected EGFR-mutant lung adenocarcinoma.

BACKGROUND: Early-stage EGFR-mutant lung adenocarcinoma (LUAD) demonstrates heterogeneous outcomes after curative surgery, yet adjuvant treatment decisions are guided by pathological stage alone. Following the ADAURA trial, adjuvant osimertinib is the standard of care for resected stage IB-IIIA EGFR-mutant LUAD; however, real-world data demonstrate that up to 40% of patients remain disease-free at five years without adjuvant osimertinib, underscoring the need for improved risk stratification. PATIENTS AND METHODS: We performed integrated clinical, genomic and transcriptomic profiling of 400 patients with resected stage IA-IIIA EGFR-mutant LUAD. EGFR-mutant recurrence risk models integrating clinical, genomic and transcriptomic data were developed and validated across one internal and three external cohorts. RESULTS: Genomic instability, including TP53 co-mutations, copy number alterations and APOBEC-associated mutational signatures, increased with pathological stage. RBM10 co-mutations were enriched in tumours with L858R mutations and correlated with upregulation of WNT signalling and epithelial-mesenchymal transition. Transcriptomic features outperformed clinical or genomic variables alone in predicting recurrence risk, and a multi-omic model demonstrated superior and reproducible performance, achieving a median concordance index of 75.4% across four independent validation cohorts. The multi-omic model stratified recurrence risk within individual pathological stages, including stage I disease, and identified patients most likely to benefit from adjuvant EGFR TKI. CONCLUSIONS: These findings define the molecular heterogeneity of early-stage EGFR-mutant LUAD and support multi-omic risk stratification to inform adjuvant EGFR TKI decisions beyond pathological stage. Prospective validation in larger cohorts will be required to confirm these findings.

Journal Article↗
PubMed2006

Effects of different combinations of gefitinib and irinotecan in lung cancer cell lines expressing wild or deletional EGFR.

EGFR mutations are a major determinant of lung tumor response to gefitinib, an EGFR-specific tyrosine kinase inhibitor. Obtaining a response from lung tumors expressing wild-type EGFR is a major obstacle. The combination of gefitinib and cytotoxic drugs is one strategy against lung cancers expressing wild-type EGFR. The DNA topoisomerase inhibitor irinotecan sulfate (CPT-11) is active against lung cancer. We examined the sensitivity of lung cancers expressing wild- or mutant-type EGFR to the combination of gefitinib and CPT-11. The in vitro effect of gefitinib and SN-38 (the active metabolite of CPT-11) was examined in seven lung cancer cell lines using the dye formation assay with a combination index. When administered concurrently, gefitinib and SN-38 had a synergistic effect in five of the seven cell lines expressing wild-type EGFR, whereas the combination was antagonistic in PC-9 cells and a PC-9 subline resistant to gefitinib and expressing deletional mutant EGFR (PC-9/ZD). When administered sequentially, treatment with SN-38 followed by gefitinib had remarkable synergistic effects in the PC-9 and PC-9/ZD cells. In an in vivo tumor-bearing model, this combination had a schedule-dependent synergistic effect in the PC-9 and PC-9/ZD cells. An immunohistochemical analysis of the tumors in mice treated with CPT-11 and gefitinib demonstrated that the number of Ki-67 positive tumor cells induced by CPT-11 treatment was decreased when CPT-11 was administered in combination with gefitinib. In conclusion, the sequential combination of CPT-11 and gefitinib is considered to be active against lung cancer.

Adenocarcinoma↗
PubMed2006

High EGFR expression predicts poor prognosis in patients with squamous cell carcinoma of the oral cavity and oropharynx: a TMA-based immunohistochemical analysis.

This retrospective study was designed to investigate the prognostic significance of EGFR overexpression in human oral squamous cell carcinoma on a long-term follow-up. EGFR expression was examined immunohistochemically on a tissue microarray (TMA) of paraffin embedded tissue specimens from 109 patients who underwent surgical treatment for squamous cell carcinoma of the oral cavity and oropharynx in the period between 1980 and 1997. High EGFR expression was found in 80 (73.42%) of the tumour samples. Kaplan-Meier curves showed that EGFR overexpression was significantly related to decreased overall survival (p=0.05). Multivariate analysis showed that EGFR overexpression is an independent prognostic marker in these patients (p=0.02, RR 3.6). These results confirm that EGFR overexpression is an independent prognostic marker in patients with squamous cell carcinoma of the oral cavity and oropharynx. The EGFR antigen represents an attractive target for targeted therapies with monoclonal antibodies or specific tyrosine-kinase inhibitors in these patients.

Adult↗
PubMed2005

Inhibition of radiation-induced EGFR nuclear import by C225 (Cetuximab) suppresses DNA-PK activity.

BACKGROUND AND PURPOSE: Inhibition of EGFR-function can induce radiosensitization in tumor cells. Purpose of our investigation was to identify the possible molecular mechanism of radiosensitization following treatment with anti-EGFR-antibody C225 (Cetuximab). MATERIALS AND METHODS: The effect of C225 on radiation response was determined in human cell lines of bronchial carcinoma (A549) and breast adenoma cells (MDA MB 231). The molecular effects of C225 on EGFR-function after irradiation were analyzed applying western blotting, immune-precipitation and kinase assays. Effects on DNA-repair were detected by quantification of gamma-H2AX positive foci 24h after irradiation. RESULTS: The EGFR specific antibody C225 induced radiosensitization in A549 and also in MDA MB 231 cells. Radiosensitization in A549 was associated with blockage of radiation-induced EGFR transport into the nucleus, and immobilized the complex of EGFR with DNA-dependent protein kinase (DNA-PK) in the cytoplasm. As a consequence radiation-induced DNA-PK activation was abolished, a process that is essential for DNA-repair after radiation exposure. Likewise C225 treatment increased the residual amount of gamma-H2AX-positive foci 24h after irradiation in A549 and in MDA MB 231 cells. CONCLUSIONS: Our results suggest that irradiation induced DNA-PK activation-essential for DNA repair-may be hampered specifically by use of the anti-EGFR-antibody C225. This process is associated with radiosensitization.

Antibodies, Monoclonal↗
PubMed2006

Galphaq expression activates EGFR and induces Akt mediated cardiomyocyte survival: dissociation from Galphaq mediated hypertrophy.

Our laboratory has previously shown that adenoviral-mediated overexpression of Galphaq in neonatal rat ventricular cardiomyocytes increases the phosphorylation of Akt, a well-established anti-apoptotic effector. As demonstrated here, Galphaq expression protects cardiomyocytes against apoptosis induced by treatment with 2-deoxyglucose (2DOG) and this protection is lost when Akt activation is prevented by treatment with LY294002 (an inhibitor of PI3K). Galphaq-induced Akt phosphorylation is not caused by increased Gbetagamma signaling and does not appear to involve PKC activation. Rather studies using the EGF receptor inhibitor AG1478 and the Src inhibitor PP2 implicate these tyrosine kinases in the pathway inducing Akt phosphorylation. EGFR phosphorylation is increased in cells expressing Galphaq and this effect is inhibited by PP2, placing Src upstream of EGFR phosphorylation. EGFR activation appears to be required for Galphaq-mediated protection since inhibition of Src or EGFR rendered cells susceptible to 2DOG-induced apoptosis. In contrast to the requirement for EGFR mediated Akt activation in cardioprotection, neither EGFR nor Akt activation are necessary for the hypertrophic increases in cell size or ANF content elicited by Galphaq overexpression. These data demonstrate that increased Galphaq activity can provide anti-apoptotic signals by eliciting EGFR phosphorylation and subsequent Akt activation, independent of the well-known ability of Galphaq signaling to elicit hypertrophy.

Animals↗
PubMed2001

EGFR tyrosine kinase inhibitor AG1478 inhibits cell proliferation and arrests cell cycle in nasopharyngeal carcinoma cells.

Nasopharyngeal carcinoma (NPC), which occurs with a high incidence in southern China and southeast Asia, is of epithelial origin with overexpression of EGF receptor. To study the effect of inhibition of EGFR signaling on nasopharyngeal carcinoma cell proliferation and cell cycle distribution, EGFR tyrosine kinase inhibitor AG1478 was employed to treat Nasopharyngeal Carcinoma CNE2 cells. The results showed that AG1478 inhibited proliferation of CNE2 cells. Immunoblot showed that AG1478 inhibited EGFR phosphorylation in CNE2 cells without reduced expression of EGFR protein. The activation of Akt and MAPK which are downstream molecules of EGFR signaling pathway, were also inhibited by AG1478. AG1478 induced cell cycle arrest in G1 phase, and the levels of protein p27 were significantly up-regulated. We concluded that inhibition of the EGFR signaling induced cell cycle arrest in G1 phase in CNE2 cells and p27 up-regulation was involved in this process. The EGFR kinase specific inhibitor is of potential to be developed into drugs for NPC treatment.

Cell Cycle↗
PubMed1993

Expression of epidermal growth factor (EGF) and epidermal growth factor receptor (EGFR) in gastric and colorectal carcinomas. An immunohistological study of 63 cases.

Immunohistochemical study for epidermal growth factor (EGF) and epidermal growth factor receptor (EGFR) was performed on paraffin-embedded tissue specimens from 39 colorectal and 24 gastric carcinomas. The carcinomas were placed in one of the following 3 groups: group 1, neither EGF nor EGFR was stained (11 gastric and 21 colorectal carcinomas); group 2, either EGF or EGFR was stained (4 gastric and 4 colorectal carcinomas); and group 3, both EGF and EGFR were stained (9 gastric and 14 colorectal carcinomas). Compared with the carcinomas in groups 1 and 2, those in group 3 had significantly higher rates of lymph node spread and serosal invasion of the gastrointestinal wall. In contrast, no significant differences were found between the EGF and/or EGFR expression and histological differentiation of carcinomas. These results suggest that gastrointestinal carcinomas expressing both EGF and EGFR display pathological features of more aggressive disease. Furthermore, the synchronous expression of EGF and EGFR indicates that these carcinomas may regulate their growth by an autocrine and/or paracrine mechanism.

Adenocarcinoma↗
PubMed2001

EGFR overexpression and radiation response in glioblastoma multiforme.

PURPOSE: Recent studies have suggested relative radioresistance in glioblastoma multiforme (GM) tumors in older patients, consistent with their shorter survival. Two common molecular genetic abnormalities in GM are age related: epidermal growth factor receptor (EGFR) overexpression in older patients and p53 mutations in younger patients. We tested whether these abnormalities correlated with clinical heterogeneity in GM response to radiation treatment. METHODS AND MATERIALS: Radiographically assessed radiation response (5-level scale) was correlated with EGFR immunoreactivity, p53 immunoreactivity, and p53 exon 5-8 mutation status in 170 GM patients treated using 2 prospective clinical protocols. Spearman rank correlation and proportional-odds ordinal regression were used for univariate and multivariate analysis. RESULTS: Positive EGFR immunoreactivity predicted poor radiographically assessed radiation response (p = 0.046). Thirty-three percent of tumors with no EGFR immunoreactivity had good radiation responses (>50% reduction in tumor size by CT or MRI), compared to 18% of tumors with intermediate EGFR staining and 9% of tumors with strong staining. There was no significant relationship between p53 immunoreactivity or mutation status and radiation response. Significant relationships were noted between EGFR score and older age and between p53 score or mutation status and younger age. CONCLUSION: The observed relative radioresistance of some GMs is associated with overexpression of EGFR.

Adolescent↗
PubMed2002

Interactions between the juxtamembrane domain of the EGFR and calmodulin measured by surface plasmon resonance.

One early response to epidermal growth factor receptor (EGFR) activation is an increase in intracellular calcium. We have used surface plasmon resonance (SPR) to study real-time interactions between the intracellular juxtamembrane (JM) region of EGFR and calmodulin. The EGFR-JM (Met(644)-Phe(688)) was expressed as a GST fusion protein and immobilised on a sensor chip surface. Calmodulin specifically interacts with EGFR-JM in a calcium-dependent manner with a high on and high off rate. Chemical modification of EGFR-JM by using arginine-selective phenylglyoxal or deletion of the basic segment Arg(645)-Arg(657) inhibits the interaction. Phosphorylation of EGFR-JM by protein kinase C (PKC) or glutamate substitution of Thr(654) inhibits the interaction, suggesting that PKC phosphorylation electrostatically interferes with calmodulin binding to basic arginine residues. Calmodulin binding was also inhibited by suramin. Our results suggest that EGFR-JM is essential for epidermal growth factor (EGF)-mediated calcium-calmodulin signalling and for signal integration between other signalling pathways.

Amino Acid Sequence↗