scholarly journals Autophosphorylation of Orphan Receptor ERBB2 Can Be Induced by Extracellular Treatment with Mildly Alkaline Media

2019 ◽  
Vol 20 (6) ◽  
pp. 1515 ◽  
Author(s):  
Oxana Serova ◽  
Natalia Chachina ◽  
Elena Gantsova ◽  
Nadezhda Popova ◽  
Alexander Petrenko ◽  
...  
Keyword(s):  
Receptor Tyrosine Kinase ◽  
Growth Factor Receptor ◽  
Receptor Activation ◽  
Orphan Receptor ◽  
Alkaline Media ◽  
Erbb2 Receptor ◽  
Independent Mechanism ◽  
Epidermal Growth ◽  
A431 Cell Line ◽  
Dose Dependent

ErbB2 is an oncogene receptor tyrosine kinase linked to breast cancer. It is a member of the epidermal growth factor receptor (EGFR) minifamily. ErbB2 is currently viewed as an orphan receptor since, by itself, it does not bind EGF-like ligands and can be activated only when overexpressed in malignant cells or complexed with ErbB3, another member of the EGFR minifamily. Here, we report that ErbB2 can be activated by extracellular application of mildly alkaline (pH 8–9) media to ErbB2-transfected cells. We also show that the activation of the ErbB2 receptor by alkali is dose-dependent and buffer-independent. The endogenous ErbB2 receptor of A431 cell line can also undergo alkali-dependent autophosphorylation. Thus, we describe a novel ligand-independent mechanism of ErbB2 receptor activation.

scholarly journals Molecular Mechanism of HER2 Rapid Internalization and Redirected Trafficking Induced by Anti-HER2 Biparatopic Antibody

Antibodies ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 49
Author(s):  
Jackie Cheng ◽  
Meina Liang ◽  
Miguel F. Carvalho ◽  
Natalie Tigue ◽  
Raffaella Faggioni ◽  
...  
Keyword(s):  
Molecular Mechanism ◽  
Receptor Tyrosine Kinase ◽  
Rational Design ◽  
Human Cancer ◽  
Growth Factor Receptor ◽  
Fluorescent Imaging ◽  
Endocytic Pathway ◽  
Erbb2 Receptor ◽  
Epidermal Growth ◽  
Kinetics Of

Amplification and overexpression of HER2 (human epidermal growth factor receptor 2), an ErbB2 receptor tyrosine kinase, have been implicated in human cancer and metastasis. A bispecific tetravalent anti-HER2 antibody (anti-HER2-Bs), targeting two non-overlapping epitopes on HER2 in domain IV (trastuzumab) and domain II (39S), has been reported to induce rapid internalization and efficient degradation of HER2 receptors. In this study, we investigated the molecular mechanism of this antibody-induced rapid HER2 internalization and intracellular trafficking. Using quantitative fluorescent imaging, we compared the internalization kinetics of anti-HER2-Bs and its parental arm antibodies, alone or in combinations and under various internalization-promoting conditions. The results demonstrated that concurrent engagement of both epitopes was necessary for rapid anti-HER2-Bs internalization. Cellular uptake of anti-HER2-Bs and parental arm antibodies occurred via clathrin-dependent endocytosis; however, inside the cells antibodies directed different trafficking pathways. Trastuzumab dissociated from HER2 in 2 h, enabling the receptor to recycle, whereas anti-HER2-Bs stayed associated with the receptor throughout the entire endocytic pathway, promoting receptor ubiquitination, trafficking to the lysosomes, and efficient degradation. Consistent with routing HER2 to degradation, anti-HER2-Bs significantly reduced HER2 shedding and altered its exosomal export. Collectively, these results enable a better understanding of the mechanism of action of anti-Her2-Bs and can guide the rational design of anti-HER2 therapeutics as well as other bispecific molecules.

Successful retreatment with erlotinib after erlotinib-related interstitial lung disease

2021 ◽  
pp. 030089162110200
Author(s):  
Haci M. Turk ◽  
Mustafa Adli ◽  
Melih Simsek ◽  
Altay Aliyev ◽  
Mehmet Besiroglu
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Interstitial Lung Disease ◽  
Epidermal Growth Factor ◽  
Tyrosine Kinase ◽  
Lung Disease ◽  
Receptor Tyrosine Kinase ◽  
Kinase Inhibitors ◽  
Growth Factor Receptor ◽  
Epidermal Growth

Background: Epidermal growth factor receptor tyrosine kinase inhibitors are effectively being used in the treatment of non-small cell lung cancer. Although most of their adverse effects are mild to moderate, they occasionally can cause life-threatening interstitial lung disease. We aimed to present a case of lung adenocarcinoma successfully re-treated with erlotinib after recovery with effective treatment of erlotinib-induced interstitial lung disease. Case description: A 54-year-old nonsmoking woman was diagnosed with metastatic adenocarcinoma of the lung. After progression with first-line chemotherapy, erlotinib 150 mg daily was initiated. On the 45th day of erlotinib treatment, interstitial lung disease occurred and erlotinib was discontinued. Clinical improvement was achieved with dexamethasone treatment and erlotinib was re-initiated. Ten weeks after re-initiation of erlotinib, 100 mg daily partial response was observed. Conclusions: Incidence of interstitial lung disease is higher in men, smokers, and patients with pulmonary fibrosis. Interstitial lung disease radiologically causes ground-glass opacity and consolidation. The physician should quickly evaluate new respiratory symptoms in patients treated with epidermal growth factor receptor tyrosine kinase inhibitors, discontinue the epidermal growth factor receptor tyrosine kinase inhibitor treatment, and initiate corticosteroids if clinical diagnosis is interstitial lung disease.

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