scholarly journals In-frame deletion in the EGF receptor alters kinase inhibition by gefitinib

2006 ◽  
Vol 397 (3) ◽  
pp. 537-543 ◽  
Author(s):  
Kazuko Sakai ◽  
Hideyuki Yokote ◽  
Kimiko Murakami-Murofushi ◽  
Tomohide Tamura ◽  
Nagahiro Saijo ◽  
...  
Keyword(s):  
Kinetic Parameters ◽  
Deletion Mutant ◽  
Kinase Inhibitors ◽  
Egf Receptor ◽  
Growth Factor Receptor ◽  
Kinetic Studies ◽  
Wild Type ◽  
Lung Cancers ◽  
The Difference ◽  
Mutant Egfr

The existence of an in-frame deletion mutant correlates with the sensitivity of lung cancers to EGFR (epidermal growth factor receptor)-targeted tyrosine kinase inhibitors. We reported previously that the in-frame 15-bp deletional mutation (delE746–A750 type deletion) was constitutively active in cells. Kinetic parameters are important for characterizing an enzyme; however, it remains unclear whether the kinetic parameters of deletion mutant EGFR are similar to those of wild-type EGFR. We analysed autophosphorylation in response to ATP and inhibition of gefitinib for deletion mutant EGFR and wild-type EGFR. Kinetic studies, examining autophosphorylation, were carried out using EGFR fractions extracted from 293-pΔ15 and 293-pEGFR cells transfected with deletion mutant EGFR and wild-type EGFR respectively. We demonstrated the difference in activities between unstimulated wild-type (Km for ATP=4.0±0.3 μM) and mutant EGFR (Km for ATP=2.5±0.2 μM). There was no difference in Km values between EGF-stimulated wild-type EGFR (Km for ATP=1.9±0.1 μM) and deletion mutant EGFR (Km for ATP=2.2±0.2 μM). These results suggest that mutant EGFR is active without ligand stimulation. The Ki value for gefitinib of the deletion mutant EGFR was much lower than that of wild-type EGFR. These results suggest that the deletion mutant EGFR has a higher affinity for gefitinib than wild-type EGFR.

scholarly journals Emerging Molecular Dependencies of Mutant EGFR-Driven Non-Small Cell Lung Cancer

Cells ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3553
Author(s):  
Dylan A. Farnsworth ◽  
Yankuan T. Chen ◽  
Georgia de Rappard Yuswack ◽  
William W. Lockwood
Keyword(s):  
Molecular Mechanisms ◽  
Kinase Inhibitors ◽  
Growth Factor Receptor ◽  
Small Cell ◽  
Egfr Mutations ◽  
Small Cell Lung ◽  
Lung Cancers ◽  
Egfr Mutant ◽  
Successive Generations ◽  
Mutant Egfr

Epidermal growth factor receptor (EGFR) mutations are the molecular driver of a subset of non-small cell lung cancers (NSCLC); tumors that harbor these mutations are often dependent on sustained oncogene signaling for survival, a concept known as “oncogene addiction”. Inhibiting EGFR with tyrosine kinase inhibitors has improved clinical outcomes for patients; however, successive generations of inhibitors have failed to prevent the eventual emergence of resistance to targeted agents. Although these tumors have a well-established dependency on EGFR signaling, there remain questions about the underlying genetic mechanisms necessary for EGFR-driven oncogenesis and the factors that allow tumor cells to escape EGFR dependence. In this review, we highlight the latest findings on mutant EGFR dependencies, co-operative drivers, and molecular mechanisms that underlie sensitivity to EGFR inhibitors. Additionally, we offer perspective on how these discoveries may inform novel combination therapies tailored to EGFR mutant NSCLC.

scholarly journals KRASoncogene in lung cancer: focus on molecularly driven clinical trials

2016 ◽  
Vol 25 (139) ◽  
pp. 71-76 ◽  
Author(s):  
Emmanuelle Kempf ◽  
Benoît Rousseau ◽  
Benjamin Besse ◽  
Luis Paz-Ares
Keyword(s):  
Kinase Inhibitors ◽  
Mammalian Target Of Rapamycin ◽  
Growth Factor Receptor ◽  
Mitogen Activated Protein Kinase ◽  
Phase Iii ◽  
Phase Iii Trial ◽  
Lung Cancers ◽  
Molecular Abnormalities ◽  
Mitogen Activated Protein ◽  
Pathway Inhibition

KRASmutations are the most frequent molecular abnormalities found in one out of four nonsmall cell lung cancers (NSCLC). Their incidence increases in cases of adenocarcinoma, smokers and Caucasian patients. Their negative value in terms of prognosis and responsiveness to both standard chemotherapy and targeted therapies remains under debate. Many drugs have been developed specifically forKRAS-mutated NSCLC patients. Direct inhibition ofRASactivation failed to show any clinical efficacy. Inhibition of downstream targets of the mitogen-activated protein kinase (MEK) pathway is a promising strategy: phase II combinations of MEK 1/2 kinase inhibitors with chemotherapy doubled patients’ clinical outcomes. One phase III trial in such a setting is ongoing. Double inhibition of MEK and epidermal growth factor receptor proteins is currently being assessed in early-phase trials. The association with mammalian target of rapamycin pathway inhibition leads to non-manageable toxicity. Other strategies, such as inhibition of molecular heat-shock proteins 90 or focal adhesion kinase are currently assessed. Abemaciclib, a cyclin-dependent kinase 4/6 inhibitor, showed promising results in a phase I trial, with a 54% disease control rate. Results of an ongoing phase III trial are warranted. Immunotherapy might be the next relevant step inKRAS-mutated NSCLC management due to the high burden of associated mutations and neo-antigens.

scholarly journals Quick Evaluation of Kinase Inhibitors by Surface Plasmon Resonance Using Single-Site Specifically Biotinylated Kinases

2013 ◽  
Vol 19 (3) ◽  
pp. 453-461 ◽  
Author(s):  
Daisuke Kitagawa ◽  
Masaki Gouda ◽  
Yasuyuki Kirii
Keyword(s):  
Surface Plasmon Resonance ◽  
Kinetic Parameters ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Kinase Inhibitors ◽  
Growth Factor Receptor ◽  
Biochemical Properties ◽  
Dissociation Rate ◽  
Single Site ◽  
Dissociation Rate Constants

In evaluating kinase inhibitors, kinetic parameters such as association/dissociation rate constants are valuable information, as are equilibrium parameters KD and IC50 values. Surface plasmon resonance (SPR) is a powerful technique to investigate these parameters. However, results are often complicated because of impaired conformations by inappropriate conditions required for protein immobilization and/or heterogeneity of the orientation of immobilization. In addition, conventional SPR experiments are generally time-consuming. Here we introduce the use of single-site specifically biotinylated kinases combined with a multichannel SPR device to improve such problems. Kinetic parameters of four compounds—staurosporine, dasatinib, sunitinib, and lapatinib—against six kinases were determined by the ProteOn XPR36 system. The very slow off-rate of lapatinib from the epidermal growth factor receptor and dasatinib from Bruton’s tyrosine kinase and colony stimulating factor 1 receptor (CSF1R) were confirmed. Furthermore, IC50 values were determined by an activity-based assay. Evaluating both physicochemical and biochemical properties would help to understand the detailed character of the compound.

Clustered Genomic Alterations in Chromosome 7p Dictate Outcomes and Targeted Treatment Responses of Lung Adenocarcinoma With EGFR-Activating Mutations

2011 ◽  
Vol 29 (25) ◽  
pp. 3435-3442 ◽  
Author(s):  
Shinsheng Yuan ◽  
Sung-Liang Yu ◽  
Hsuan-Yu Chen ◽  
Yi-Chiung Hsu ◽  
Kang-Yi Su ◽  
...  
Keyword(s):  
Lung Adenocarcinoma ◽  
Kinase Inhibitors ◽  
Growth Factor Receptor ◽  
Disease Free Survival ◽  
Comparative Genomic ◽  
Wild Type ◽  
Free Survival ◽  
Activating Mutation ◽  
Disease Free ◽  
Egfr Tkis

Purpose Although epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have been proven more effective for patients with lung adenocarcinoma with EGFR-activating mutation rather than wild type, the former group still includes approximately 30% nonresponders. The molecular basis of this substantial response heterogeneity is unknown. Our purpose was to seek molecular aberrations contributing to disease progression at the genome-wide level and identify the prognostic signature unique to patients with EGFR-activating mutation. Patients and Methods We first investigated the molecular differences between tumors with EGFR-activating mutation and wild-type tumors by conducting high-density array comparative genomic hybridization on a collection of 138 adenocarcinoma tissues. We then used an independent group of 114 patients to validate the clinical relevance of copy-number alterations (CNAs) in predicting overall and disease-free survival. Finally, focusing on 23 patients with EGFR mutation receiving EGFR-TKI treatment, we investigated the association between CNAs and response to EGFR-TKIs. Results We identified chromosome regions with differential CNAs between tumors with EGFR-activating mutation and wild-type tumors and found the aberration sites to cluster highly on chromosome 7p. A cluster of six representative chromosome 7p genes predicted overall and disease-free survival for patients with EGFR-activating mutation but not for those with wild type. Importantly, simultaneous presence of more genes with increased CNAs in this cluster correlated with less favorable response to EGFR-TKIs in patients with EGFR-activating mutation. Conclusion Our results shed light on why responses to EGFR-TKIs are heterogeneous among patients with EGFR-activating mutation. They may lead to better patient management in this population.

scholarly journals A Tale of Two Cbls: Interplay of c-Cbl and Cbl-b in Epidermal Growth Factor Receptor Downregulation

2008 ◽  
Vol 28 (9) ◽  
pp. 3020-3037 ◽  
Author(s):  
Steven Pennock ◽  
Zhixiang Wang
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Egf Receptor ◽  
Growth Factor Receptor ◽  
Wild Type ◽  
Receptor Downregulation ◽  
Epidermal Growth ◽  
Precise Role ◽  
Second Peak

ABSTRACT The precise role of Cbl in epidermal growth factor (EGF) receptor (EGFR) endocytosis and trafficking remains to be fully uncovered. Here, we showed that mutant EGFR1044, which was truncated after residue 1044, did not associate with c-Cbl and was not ubiquitinated initially in response to EGF but was internalized with kinetics similar to those of wild-type EGFR. This finding indicates that c-Cbl-mediated ubiquitination is not required for EGF-induced EGFR endocytosis. We also showed that the previously identified internalization-deficient mutant receptor EGFR1010LL/AA bound to c-Cbl and was fully ubiquitinated in response to EGF, which indicates that c-Cbl binding and ubiquitination are not sufficient for EGFR internalization. We next investigated EGFR trafficking following EGFR internalization. We found that c-Cbl disassociation from EGFR occurred well in advance of EGFR degradation and that this event was concurrent with the selective dephosphorylation of EGFR at Y1045. This finding suggests that once EGFR is ubiquitinated, continual Cbl association is not required for EGFR degradation. Because EGFR1044 is ubiquitinated and degraded similarly to wild-type EGFR, we examined the role of another prominent Cbl homologue, Cbl-b, and found that Cbl-b was associated with both EGFR and EGFR1044. Further study showed that Cbl-b bound to EGFR at two regions: one in the C-terminal direction from residue 1044 and one in the N-terminal direction from residue 958. Moreover, Cbl-b association with EGFR rose markedly following a decrease in c-Cbl association, corresponding to a second peak of EGFR ubiquitination occurring later in EGFR trafficking. Using RNA interference to knock down both c-Cbl and Cbl-b, we were able to abolish EGFR downregulation. This knockdown had no affect on the rate of EGF-induced EGFR internalization. We found that the two Cbls accounted for total receptor ubiquitination and that while c-Cbl and Cbl-b are each alone sufficient to effect EGFR degradation, both are involved in the physiological, EGF-mediated process of receptor downregulation. Furthermore, these data ultimately reveal a previously unacknowledged temporal interplay of two major Cbl homologues with the trafficking of EGFR.

scholarly journals Inhibition of the FGF/FGFR System Induces Apoptosis in Lung Cancer Cells via c-Myc Downregulation and Oxidative Stress

2020 ◽  
Vol 21 (24) ◽  
pp. 9376
Author(s):  
Arianna Giacomini ◽  
Sara Taranto ◽  
Sara Rezzola ◽  
Sara Matarazzo ◽  
Elisabetta Grillo ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Lung Cancer ◽  
Kinase Inhibitors ◽  
Lung Tumor ◽  
Growth Factor Receptor ◽  
Therapeutic Benefit ◽  
Dependent Lung ◽  
Lung Cancers ◽  
Molecular Features ◽  
Promising Therapeutic Approach

Lung cancer represents an extremely diffused neoplastic disorder with different histological/molecular features. Among the different lung tumors, non-small-cell lung cancer (NSCLC) is the most represented histotype, characterized by various molecular markers, including the expression/overexpression of the fibroblast growth factor receptor-1 (FGFR1). Thus, FGF/FGFR blockade by tyrosine kinase inhibitors (TKi) or FGF-ligand inhibitors may represent a promising therapeutic approach in lung cancers. In this study we demonstrate the potential therapeutic benefit of targeting the FGF/FGFR system in FGF-dependent lung tumor cells using FGF trapping (NSC12) or TKi (erdafitinib) approaches. The results show that inhibition of FGF/FGFR by NSC12 or erdafitinib induces apoptosis in FGF-dependent human squamous cell carcinoma NCI-H1581 and NCI-H520 cells. Induction of oxidative stress is the main mechanism responsible for the therapeutic/pro-apoptotic effect exerted by both NSC12 and erdafitinib, with apoptosis being abolished by antioxidant treatments. Finally, reduction of c-Myc protein levels appears to strictly determine the onset of oxidative stress and the therapeutic response to FGF/FGFR inhibition, indicating c-Myc as a key downstream effector of FGF/FGFR signaling in FGF-dependent lung cancers.

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