Extracellular cysteine/cystine redox regulates the p44/p42 MAPK pathway by metalloproteinase-dependent epidermal growth factor receptor signaling

2005 ◽  
Vol 289 (1) ◽  
pp. G70-G78 ◽  
Author(s):  
Yvonne S. Nkabyo ◽  
Young-Mi Go ◽  
Thomas R. Ziegler ◽  
Dean P. Jones
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Redox State ◽  
Mapk Pathway ◽  
Growth Factor Receptor ◽  
Mitogen Activated Protein Kinase ◽  
Growth Factor Signaling ◽  
Epidermal Growth ◽  
Mapk Inhibitors

Previous research shows that stimulation of proliferation of colon carcinoma (Caco-2) cells by a more reduced extracellular cysteine/cystine (Cys/CySS) redox state occurs with no apparent effect on intracellular glutathione and that this stimulation is lost on addition of epidermal growth factor. The purpose of the present study was to determine whether a more reduced extracellular Cys/CySS redox state activates the mitogenic p44/p42 mitogen-activated protein kinase (MAPK) pathway and whether this is signaled through the epidermal growth factor receptor (EGFR). Caco-2 cells were exposed to a range of physiological extracellular redox conditions from −150 to 0 mV. In the absence of added growth factors, the most reduced (−150 mV) redox state induced an 80% increase in EGFR phosphorylation, and this was followed by a marked increase in phosphorylation of p44/p42 MAPK. Inhibitors of EGFR (AG1478) and p44/p42 MAPK (U0126) phosphorylation blocked redox-dependent p44/p42 phosphorylation, indicating that signaling occurred by EGFR. These effects were inhibited by pretreatment with a nonpermeant alkylating agent, showing that signaling involved thiols accessible to the extracellular space. The EGFR ligand TGF-α was increased in culture medium at more reduced redox states. Redox-dependent phosphorylation of EGFR was completely prevented by a metalloproteinase inhibitor (GM6001), and an antibody to TGF-α partially inhibited the phosphorylation of p44/p42 MAPK by redox. Thus the data show that a redox-dependent activation of metalloproteinase can stimulate the mitogenic p44/p42 MAPK pathway by a TGF-α-dependent mechanism. Because Cys availability and Cys/CySS redox are dependent on nutrition, disease, and environmental exposures, the results suggest that cell proliferation could be influenced physiologically by Cys-dependent redox effects on growth factor signaling pathways.

scholarly journals Multiple mechanisms collectively regulate clathrin-mediated endocytosis of the epidermal growth factor receptor

2010 ◽  
Vol 189 (5) ◽  
pp. 871-883 ◽  
Author(s):  
Lai Kuan Goh ◽  
Fangtian Huang ◽  
Woong Kim ◽  
Steven Gygi ◽  
Alexander Sorkin
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Protein Kinase ◽  
Epidermal Growth Factor ◽  
Growth Factor Receptor ◽  
Adaptor Protein ◽  
Kinase Domain ◽  
Mitogen Activated Protein Kinase ◽  
Epidermal Growth ◽  
Egfr Mutant

Endocytosis of the epidermal growth factor receptor (EGFR) is important for the regulation of EGFR signaling. However, EGFR endocytosis mechanisms are poorly understood, which precludes development of approaches to specifically inhibit EGFR endocytosis and analyze its impact on signaling. Using a combination of receptor mutagenesis and RNA interference, we demonstrate that clathrin-dependent internalization of activated EGFR is regulated by four mechanisms, which function in a redundant and cooperative fashion. These mechanisms involve ubiquitination of the receptor kinase domain, the clathrin adaptor complex AP-2, the Grb2 adaptor protein, and three C-terminal lysine residues (K1155, K1158, and K1164), which are acetylated, a novel posttranslational modification for the EGFR. Based on these findings, the first internalization-defective EGFR mutant with functional kinase and normal tyrosine phosphorylation was generated. Analysis of the signaling kinetics of this mutant revealed that EGFR internalization is required for the sustained activation of protein kinase B/AKT but not for the activation of mitogen-activated protein kinase.

scholarly journals Epidermal Growth Factor Signaling and Mitogenesis inPlcg1 Null Mouse Embryonic Fibroblasts

1998 ◽  
Vol 9 (4) ◽  
pp. 749-757 ◽  
Author(s):  
Qun-sheng Ji ◽  
Sandra Ermini ◽  
Josep Baulida ◽  
Feng-lei Sun ◽  
Graham Carpenter
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Growth Factor Receptor ◽  
Receptor Activation ◽  
Mitogen Activated Protein Kinase ◽  
Null Mouse ◽  
Growth Factor Signaling ◽  
Mitogen Activated Protein ◽  
Epidermal Growth ◽  
Early Mouse

Gene targeting techniques and early mouse embryos have been used to produce immortalized fibroblasts genetically deficient in phospholipase C (PLC)-γ1, a ubiquitous tyrosine kinase substrate.Plcg1 −/− embryos die at embryonic day 9; however, cells derived from these embryos proliferate as well as cells from Plcg1 +/+ embryos. The null cells do grow to a higher saturation density in serum-containing media, as their capacity to spread out is decreased compared with that of wild-type cells. In terms of epidermal growth factor receptor activation and internalization, or growth factor induction of mitogen-activated protein kinase, c-fos, or DNA synthesis in quiescent cells, PLcg1 −/− cells respond equivalently to PLcg1 +/+ cells. Also, null cells are able to migrate effectively in a wounded monolayer. Therefore, immortalized fibroblasts do not require PLC-γ1 for many responses to growth factors.

scholarly journals Revisiting Epidermal Growth Factor Receptor (EGFR) Amplification as a Target for Anti-EGFR Therapy: Analysis of Cell-Free Circulating Tumor DNA in Patients With Advanced Malignancies

2019 ◽  
pp. 1-14 ◽  
Author(s):  
Shumei Kato ◽  
Ryosuke Okamura ◽  
Manvita Mareboina ◽  
Suzanna Lee ◽  
Aaron Goodman ◽  
...  
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Checkpoint Inhibitors ◽  
Growth Factor Receptor ◽  
Egfr Inhibitors ◽  
Mitogen Activated Protein Kinase ◽  
Egfr Amplification ◽  
Epidermal Growth ◽  
Tumor Dna

Purpose To date, evidence for tissue epidermal growth factor receptor (EGFR) overexpression as a biomarker for anti-EGFR therapies has been weak. We investigated the genomic landscape of EGFR amplification in blood-derived cell-free tumor DNA (cfDNA) across diverse cancers and the role of anti-EGFR therapies in achieving response. Methods We assessed EGFR amplification status among 28,584 patients with malignancies evaluated by clinical-grade next-generation sequencing (NGS) of blood-derived cfDNA (54- to 73-gene panel). Furthermore, we curated the clinical characteristics of 1,434 patients at the University of California San Diego who had cfDNA testing by this NGS test. Results Overall, EGFR amplification was detected in cfDNA from 8.5% of patients (2,423 of 28,584), most commonly in colorectal (16.3% [458 of 2,807]), non–small-cell lung (9.0% [1,096 of 12,197]), and genitourinary cancers (8.1% [170 of 2,104]). Most patients had genomic coalterations (96.9% [95 of 98]), frequently involving genes affecting other tyrosine kinases (72.4% [71 of 98]), mitogen-activated protein kinase cascades (56.1% [55 of 98]), cell-cycle–associated signals (52.0% [51 of 98]), and the phosphoinositide 3-kinase pathway (35.7% [35 of 98]). EGFR amplification emerged in serial cfDNA after various anticancer therapies (n = 6), including checkpoint inhibitors (n = 4), suggesting a possible role for these amplifications in acquired resistance. Nine evaluable patients with EGFR amplification were treated with anti-EGFR–based regimens; five (55.6%) achieved partial responses, including three patients whose tissue NGS lacked EGFR amplification. Conclusion EGFR amplification was detected in cfDNA among 8.5% of 28,584 diverse cancers. Most patients had coexisting alterations. Responses were observed in five of nine patients who received EGFR inhibitors. Incorporating EGFR inhibitors into the treatment regimens of patients harboring EGFR amplification in cfDNA merits additional study.

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