EGFR Overexpression Lysate

HEK293T cells in 10-cm dishes were transiently transfected with a non-lipid polymer transfection reagent specially designed and manufactured for large volume DNA transfection. Transfected cells were cultured for 48hrs before collection. The cells were lysed in modified RIPA buffer (25mM Tris-HCl pH7.6, 150mM NaCl, 1% NP-40, 1mM EDTA, 1xProteinase inhibitor cocktail mix, 1mM PMSF and 1mM Na3VO4, and then centrifuged to clarify the lysate. Protein concentration was measured by BCA protein assay kit.

Epidermal growth factor receptor (EGFR), also known as ErbB1 and HER1, is a type I glycoprotein that belongs the ErbB subfamily of receptor tyrosine kinases (RTKs), which includes ErbB2/HER2, ErbB3/HER3, and ErbB4/HER4 (1,2). EGFR plays an important role in epithelial cell development and homeostasis and as a driver of tumorigenesis in cancer (1,2). The human EGFR is protein 1210 amino acids (aa) in length with a theoretical molecular weight (MW) of 134 kDa (1). The protein consists of a short signal peptide, an extracellular domain (ECD) divided into four subdomains (I-IV), a transmembrane region, an intracellular juxtamembrane segment, a tyrosine kinase domain, and C-terminal tail (1-3). Within the ECD, human EGFR has 88-90% aa sequence identity with mouse and rat EGFR. EGFR has four known specific ligands: EGF, amphiregulin, epigen, and transforming growth factor alpha (TGF-alpha). EGFR ligands betacellulin, epiregulin, and herapin binding (HB)-EGF have dual specificity with ErbB4 (1,3). Ligand binding to the extracellular domain of EFGR leads to receptor homodimerization, or heterodimerization with other ErbB family members, and EGFR activation. This results in subsequent phosphorylation and activation of intracellular signaling pathways, such as MAPK and PI3K/Akt (2,3). EGFR signaling is essential for many cellular processes including proliferation, differentiation, migration, and apoptosis (1,3,5).

In addition to its role in normal development, EGFR mutations or overexpression is observed in many tumors, including breast cancer, non-small cell lung carcinoma (NSCLC), colon cancer, and more (3-6). Small molecule tyrosine kinase inhibitors (TKIs), like gefitinib, erlotinib, and afatinib, have shown great efficacy in treating patients with EGFR activating mutations, especially for NSCLC (4-6). However, most patients eventually develop acquired resistance to TKIs and thus combination and alternative therapies are in development (4-6). A third-generation TKI, osimertinib, is approved for NSCLC patients with resistance to first-line EGFR TKI treatment (6). Additionally, combination therapies of EGFR TKIs with monoclonal antibody immunotherapies, like anti-PD-L1, are being further investigated in clinical trials (6).

References

1. Roskoski R Jr. Small molecule inhibitors targeting the EGFR/ErbB family of protein-tyrosine kinases in human cancers. Pharmacol Res. 2019; 139:395-411. https://doi.org/10.1016/j.phrs.2018.11.014

2. Sigismund S, Avanzato D, Lanzetti L. Emerging functions of the EGFR in cancer. Mol Oncol. 2018; 12(1):3-20. https://doi.org/10.1002/1878-0261.12155

3. Normanno N, De Luca A, Bianco C, et al. Epidermal growth factor receptor (EGFR) signaling in cancer. Gene. 2006; 366(1):2-16. https://doi.org/10.1016/j.gene.2005.10.018

4. Liu Q, Yu S, Zhao W, Qin S, Chu Q, Wu K. EGFR-TKIs resistance via EGFR-independent signaling pathways. Mol Cancer. 2018; 17(1):53. https://doi.org/10.1186/s12943-018-0793-1

5. Harrison PT, Vyse S, Huang PH. Rare epidermal growth factor receptor (EGFR) mutations in non-small cell lung cancer. Semin Cancer Biol. 2020; 61:167-179. https://doi.org/10.1016/j.semcancer.2019.09.015

6. Wu SG, Shih JY. Management of acquired resistance to EGFR TKI-targeted therapy in advanced non-small cell lung cancer. Mol Cancer. 2018; 17(1):38. https://doi.org/10.1186/s12943-018-0777-1

This product is for research use only and is not approved for use in humans or in clinical diagnosis. Lysates are guaranteed for 6 months from date of receipt.

Array NBP2-04608

• EGFR Antibodies
• EGFR Antibody Pair
• EGFR Lysate
• EGFR Proteins
• EGFR ELISAs
• EGFR Proteins and Enzymes