Expression of epithelial to mesenchymal transition markers in lung cancer cell lines

Abstract

Epithelial-mesenchymal transition (EMT) is the reversible transformation of epithelial cells into mesenchymal cells, during which the cells lose their epithelial characteristics and acquire invasive and migratory abilities. This process is observed in various types of cancer, including lung cancer. Lung cancer is among the most extensively researched type due to the poor prognosis for patients, as it is often already at a metastatic stage at the time of diagnosis. The main aim of this study was to utilise TGF-β as a potent EMT inducer to investigate the EMT process in 2 lung cancer cell lines, H1975 and A549. This was achieved by examining cellular viability and gene expression of the cancer cell lines following TGF-β treatment at various doses (1.25, 2.5, 5, 10, 20 ng/ml) and time points (24 and 48 hours). The genes chosen included 2 epithelial markers (EpCAM, CDH1) and 4 mesenchymal markers (VIM, FN1, ZEB1, SNAIL1). The methods used included cell culturing, viability assays to determine the optimal seeding concentration, the optimal FBS concentration, and the optimal TGF-β concentration. RNA was then extracted from the drug-treated and untreated cells, followed by cDNA synthesis, and qPCR. The viability assays revealed differences in response to TGF-β between the cell lines: the viability of H1975 cells decreases over time, whereas A549 cells demonstrate enhanced viability under higher doses and prolonged exposure. The gene expression results aligned with EMT progression as TGF-β dosage increased, exhibiting downregulation of epithelial markers, such as CDH1, and upregulation of mesenchymal markers, such as SNAIL1. This study illustrated variability in gene expression between cell lines, emphasising their distinct phenotypic characteristics. Early SNAIL1 upregulation (24 hours) post-TGF-β treatment supports ongoing research, which suggests SNAIL1-targeted therapy as a potential mechanism for early clinical intervention in lung cancer treatment.