Functional mutation analysis of EGFR family genes and corresponding lymph node metastases in head and neck squamous cell carcinoma

Abstract

Tumors with certain mutations in the epidermal growth factor receptor (EGFR) family genes dramatically respond to EGFR inhibitors. Therefore, these mutations are important factors that influence disease progression and patient survival. We previously studied the mutation status of EGFR in patients with head and neck squamous cell carcinoma (HNSCC). However, the mutation status of lymph node metastases and the frequency of mutations in EGFR family genes have not been extensively studied. In this study, we sequenced the catalytic domains of the three other members of the EGFR family, HER2, HER3, and HER4 in 92 clinical samples of HNSCC. We identified a HER2 mutation (K716E) in one sample but no mutations were found in HER3 or HER4. Next to investigate the relationship between EGFR mutations and tumor metastasis, we compared the DNA sequences of the EGFR gene between the primary tumor and the lymph node metastasis in 31 clinical samples. Only one of the patients with an EGFR mutation in the primary HNSCC carried the same mutation (L858R) in the lymph node metastasis. Finally, we explored the tumorigenic potential of the EGFR mutations that we had previously identified and their sensitivity to two different EGFR tyrosine kinase inhibitors (CL-387785, OSI-420). Ba/F3 cells transformed with mutant EGFR genes were sensitive to treatment with lower concentrations of CL-387785 than of OSI-420. These results contribute to our understanding of the genetic basis of drug sensitivity and will help design drugs that specifically target different subtypes of HNSCC.

Autologous human nasal epithelial cell sheet using temperature-responsive culture insert for transplantation after middle ear surgery

“…Cytokeratin (CK), vimentin and cell–cell junction proteins ( β ‐catenin and laminin) were detected by western blotting with the corresponding mouse monoclonal antibodies (Novocastra Laboratories Ltd): anti‐pan‐cytokeratin, 1:200 dilution; anti‐vimentin, 1:200 dilution; anti‐ β ‐catenin, 1:200 dilution; or anti‐laminin, 1:50 dilution. For detection, transferred membranes were blocked by Blocking One solution, and primary and secondary antibodies were diluted in Can Get Signal immunoreaction enhancer solution (Toyobo Co. Ltd, Osaka, Japan), as previously described (Hama et al ., ). The bands were visualized using the ECL‐plus detection kit (GE Healthcare UK, Buckinghamshire, UK) and analysed by densitometry (ATTO, Tokyo, Japan) in order to calculate the expression level of pan‐cytokeratin, vimentin, β ‐catenin and laminin.…”

Targeting the Immune Microenvironment in the Treatment of Head and Neck Squamous Cell Carcinoma

“…The mechanisms of resistance to epidermal growth factor receptor (EGFR) inhibitors have been known for decades and they include nuclear localization of EGFR, activation of other ErbB family receptors, mutant forms of the receptor (EGFRvIII), or cross-talk with other signaling pathways (97, 98). However, issues of resistant mechanisms to immunotherapy have been gradually emphasized recently.…”

ERK2-dependent reactivation of Akt mediates the limited response of tumor cells with constitutive K-RAS activity to PI3K inhibition

“…The mutations in EGFR described for NSCLC, such as deletions in exon 19 and a point mutation in exon 21 (L858R), are rare or have not been observed in HNSCC. 12,13 However, the expression of EGFR variant III (EGFRvIII) has been demonstrated in approximately 40% of HNSCCs. 14 The EGFRvIII mutation was first identified in glioblastomas and results in constitutively active MAPK and PI3K/ Akt cascades.…”