scholarly journals Enhanced dimerization drives ligand-independent activity of mutant epidermal growth factor receptor in lung cancer

2015 ◽  
Vol 26 (22) ◽  
pp. 4087-4099 ◽  
Author(s):  
Christopher C. Valley ◽  
Donna J. Arndt-Jovin ◽  
Narain Karedla ◽  
Mara P. Steinkamp ◽  
Alexey I. Chizhik ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Molecular Mechanisms ◽  
Critical Role ◽  
Resonance Energy Transfer ◽  
Growth Factor Receptor ◽  
Resonance Energy ◽  
Epidermal Growth

Mutations within the epidermal growth factor receptor (EGFR/erbB1/Her1) are often associated with tumorigenesis. In particular, a number of EGFR mutants that demonstrate ligand-independent signaling are common in non–small cell lung cancer (NSCLC), including kinase domain mutations L858R (also called L834R) and exon 19 deletions (e.g., ΔL747-P753insS), which collectively make up nearly 90% of mutations in NSCLC. The molecular mechanisms by which these mutations confer constitutive activity remain unresolved. Using multiple subdiffraction-limit imaging modalities, we reveal the altered receptor structure and interaction kinetics of NSCLC-associated EGFR mutants. We applied two-color single quantum dot tracking to quantify receptor dimerization kinetics on living cells and show that, in contrast to wild-type EGFR, mutants are capable of forming stable, ligand-independent dimers. Two-color superresolution localization microscopy confirmed ligand-independent aggregation of EGFR mutants. Live-cell Förster resonance energy transfer measurements revealed that the L858R kinase mutation alters ectodomain structure such that unliganded mutant EGFR adopts an extended, dimerization-competent conformation. Finally, mutation of the putative dimerization arm confirmed a critical role for ectodomain engagement in ligand-independent signaling. These data support a model in which dysregulated activity of NSCLC-associated kinase mutants is driven by coordinated interactions involving both the kinase and extracellular domains that lead to enhanced dimerization.

scholarly journals Ubiquitin ligase SMURF2 enhances epidermal growth factor receptor stability and tyrosine-kinase inhibitor resistance

2020 ◽  
Vol 295 (36) ◽  
pp. 12661-12673 ◽  
Author(s):  
Paramita Ray ◽  
Krishnan Raghunathan ◽  
Aarif Ahsan ◽  
Uday Sankar Allam ◽  
Shirish Shukla ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Tyrosine Kinase ◽  
Molecular Mechanisms ◽  
Growth Factor Receptor ◽  
Receptor Internalization ◽  
Egfr Mutations ◽  
Epidermal Growth

The discovery of activating epidermal growth factor receptor (EGFR) mutations spurred the use of EGFR tyrosine kinase inhibitors (TKIs), such as erlotinib, as the first-line treatment of lung cancers. We previously reported that differential degradation of TKI-sensitive (e.g. L858R) and resistant (T790M) EGFR mutants upon erlotinib treatment correlates with drug sensitivity. We also reported that SMAD ubiquitination regulatory factor 2 (SMURF2) ligase activity is important in stabilizing EGFR. However, the molecular mechanisms involved remain unclear. Here, using in vitro and in vivo ubiquitination assays, MS, and superresolution microscopy, we show SMURF2–EGFR functional interaction is important for EGFR stability and response to TKI. We demonstrate that L858R/T790M EGFR is preferentially stabilized by SMURF2-UBCH5 (an E3-E2)-mediated polyubiquitination. We identified four lysine residues as the sites of ubiquitination and showed that replacement of one of them with acetylation-mimicking glutamine increases the sensitivity of mutant EGFR to erlotinib-induced degradation. We show that SMURF2 extends membrane retention of EGF-bound EGFR, whereas SMURF2 knockdown increases receptor sorting to lysosomes. In lung cancer cell lines, SMURF2 overexpression increased EGFR levels, improving TKI tolerance, whereas SMURF2 knockdown decreased EGFR steady-state levels and sensitized lung cancer cells. Overall, we propose that SMURF2-mediated polyubiquitination of L858R/T790M EGFR competes with acetylation-mediated receptor internalization that correlates with enhanced receptor stability; therefore, disruption of the E3-E2 complex may be an attractive target to overcome TKI resistance.

Therapeutic Approaches for the Treatment of Epidermal Growth Factor Receptor Mutated Lung Cancer

2018 ◽  
Vol 18 (8) ◽  
pp. 773-791
Author(s):  
Dhaval Sanchala ◽  
Lokesh K. Bhatt ◽  
Kedar S. Prabhavalkar
Keyword(s):  
Lung Cancer ◽  
Clinical Trial ◽  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Growth Factor Receptor ◽  
Driver Mutations ◽  
Therapeutic Approaches ◽  
Epidermal Growth ◽  
Egfr Mutant

Lung cancer surfaces to be the predominant determinant of mortality worldwide constituting 13% and 19% of all new cancer cases and deaths related to cancer respectively. Molecular profiling has now become a regular trend in lung cancer to identify the driver mutations. Epidermal Growth Factor Receptor (EGFR) is the most regular driver mutation encountered in Non-Small Cell Lung Cancer (NSCLC). Targeted therapies are now available for the treatment of EGFR mutant NSCLC. EGFR mutation is more frequently expressed in adenocarcinoma than squamous cell carcinoma. This article presents a detailed molecular insight of the therapeutic approaches for the treatment of EGFR mutant lung cancer. The article delineates molecular mechanism of the drugs that are approved, the drugs that are in clinical trial and the drugs that have not entered a clinical trial but shows promising future in the treatment of EGFR mutant lung cancer. Furthermore, this article provides concise information on relevant combinational or monotherapy clinical trials that have been completed for various approaches.

Recent Advances on Epidermal Growth Factor Receptor as a Molecular Target for Breast Cancer Therapeutics

2020 ◽  
Vol 21 ◽  
Author(s):  
Swathi R. Shetty ◽  
Ragini Yeeravalli ◽  
Tanya Bera ◽  
Amitava Das
Keyword(s):  
Breast Cancer ◽  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Tyrosine Kinase ◽  
Critical Role ◽  
Growth Factor Receptor ◽  
Type I ◽  
Egfr Inhibition ◽  
Epidermal Growth

: Epidermal growth factor receptor (EGFR), a type-I transmembrane protein with intrinsic tyrosine kinase activity is activated by peptide growth factors such as EGF, epigen, amphiregulin, etc. EGFR plays a vital role in regulating cell growth, migration, and differentiation in various tissue-specific cancers. It has been reported to be overexpressed in lung, head, and neck, colon, brain, pancreatic, and breast cancer that trigger tumor progression and drug resistance. EGFR overexpression alters the signaling pathway and induces cell division, invasion, and cell survival. Our prior studies demonstrated that EGFR inhibition modulates chemosensitivity in breast cancer stem cells thereby serving as a potential drug target for breast cancer mitigation. Tyrosine kinase inhibitors (Lapatinib, Neratinib) and monoclonal antibodies (Trastuzumab) targeting EGFR have been developed and approved by the US FDA for clinical use against breast cancer. This review highlights the critical role of EGFR in breast cancer progression and enumerates the various approaches being undertaken to inhibit aggressive breast cancers by suppressing the downstream pathways. Further, the mechanisms of action of potential molecules at various stages of drug development as well as clinically approved drugs for breast cancer treatment are illustrated.

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