Gene regulation and small molecule therapeutics in non-small cell lung cancer

Abstract

Background: Lung cancer is one of the commonest cancers worldwide and the highest cause of cancer related mortality. Mutations in epidermal growth factor receptor (EGFR) affect the mTOR pathway, which is essential for protein translation and which is frequently dysregulated in non-small cell lung cancer (NSCLC). Aberrant EGFR signalling confers resistance to chemotherapy, making it difficult to treat. Several EGFR tyrosine kinase inhibitors (TKIs) are available but although these are initially effective, resistance is inevitable. Afatinib is a 2nd generation TKI indicated to treat EGFR mutant NSCLC but is subject to resistance by emergence of new mutations. Translationally controlled tumour protein (TCTP) is a protein which affects mTOR signalling. Inhibiting the mTOR pathway via EGFR using afatinib and via TCTP using an antisense oligonucleotide (ASO) simultaneously might be useful in treating EGFR mutant NSCLC. Aims: The aim of this project is to investigate a novel combinatory regimen of EGFR TKIs and TCTP ASO vs EGFR TKI or TCTP ASO monotherapy on EGFR mutant NSCLC models. Methods: HCC827 and H1975 cell lines were treated with afatinib and transfected with TCTP ASO alone or in combination and their effects were measured using viability assays and wound healing assays. Enzyme linked immunosorbent assay (ELISA) was employed to measure eIF4E protein, downstream of mTOR as an indication of afatinib effect. Real time quantitative polymerase chain reaction (RT-qPCR) was used to confirm knockdown of TPT1 gene by TCTP ASO. Results: Both afatinib and TCTP ASO were effective in reducing cell viability in both cell lines. Further, afatinib affected cell migration in both cell lines whereas TCTP ASO only had an effect on H1975 cell migration. Combinatory therapy with afatinib and TCTP ASO was more effective in reducing cell viability in both cell lines than afatinib or TCTP ASO monotherapy.