Abstract 4654: The primary study of the correlation between mRNA expression and protein phosphorylation of epidermal growth factor receptor EGFR in colorectal and breast cancer cell lines

Abstract

Abstract The EGFR family is a group of receptor tyrosine kinases that mediates cell proliferation, migration, and differentiation. Activation of EGFR signaling is triggered by ligand-binding induced receptor dimerization. The dimerization activates the intracellular kinase domains of the receptor, resulting in autophosphorylation of C-terminal tail and the initiation of downstream signaling. EGFR overexpression is correlated with more aggressive clinical indications in multiple types of cancer, including colon, breast, lung, and head and neck carcinoma. Clinical studies show that EGFR-directed therapeutic approaches improved better outcomes of metastatic lung, colorectal, and head and neck cancers. Predictive biomarkers are being developed to deliver personalized therapies. Therefore, it is important to determine the protein as well as molecular biomarker expression for selecting targeted therapies. Here we present a panel cancer cell lines to examine EGFR expressions at a molecular biomarker level (mRNA) as well as a protein level of phosphorylated EGFR(pS1060). Colon cancer cell lines HT29, HCT116, SW620, as well as the breast cancer cell line SKBR3, were cultured and processed onto formalin-fixed paraffin-embedded (FFPE) CellMax pellets. Expression levels of EGFR mRNA in the FFPE slides were examined with RNAScope technology to visualize single RNA molecules per cell by using probes specifically against EGFR. Expression of phosphorylated EGFR was examined by the phosphospecific EGFR (pS1070) antibodies by using immunohistochemistry (IHC). EGFR mRNA expression was detected in HT29 and HCT 116 cells showing strong punctuated signals in the cytoplasm. However, no EGFR mRNA signals were detected in SW620 cells. Breast cancer cell line SKBR3 showed abundant EGFR mRNA expression. Phosphorylated EGFR were found in the cell HT29, HCT 116 and SKBR3 cells with membrane staining pattern. No phosphorylated EGFR was observed in SW620 cells using Immunochemistry staining. Together, our results demonstrated that the EGFR mRNA expression is correlated to the phosphorylation of EGFR in these cancer cell lines. We concluded that the EGFR mRNA probes, phosphorylated EGFR antibodies, and/or the cell lines can be served as the control-references for clinical biomarker screening. Citation Format: Hongwei Wang, Catherine Ma, Yuan Zhou. The primary study of the correlation between mRNA expression and protein phosphorylation of epidermal growth factor receptor EGFR in colorectal and breast cancer cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4654. doi:10.1158/1538-7445.AM2017-4654