Expression of epithelial-to-mesenchymal transition markers in breast and colorectal cancer cell lines

Abstract

Epithelial-to-mesenchymal transition (EMT) is the main process which causes tumour metastasis and involves a series of cellular biochemical and morphological changes. These cellular changes are coupled with a shift in biomarker expression which are potential metastatic indicators. Transforming growth factor β (TGF-β) is known to have various pleiotropic effects on cancer cells, some of which could lead to increased tumour aggressivity. Histone modifications are also known to play significant roles in the activation or suppression of tumorigenic properties. In this study, the effects of TGFβ1 and a histone deacetylase inhibitor (HDACi), valproic acid (VPA), on cellular proliferation of breast cancer (BC) and colorectal cancer (CRC) cell lines was investigated using wound healing assays. TGF-β1 and VPA were found to suppress proliferation of SW480 cells. VPA was also found to suppress cellular proliferation of MCF7 cells, but increased proliferation of DLD1 cells. The effects of one of the major isoforms of TGF-β, TGF-β1, on EMT gene expression of treated SW480, DLD1, MDAMB-436 and BT-20 cells was analysed via a hybridisation-based multiplexing RNA quantification assay. An increase in the FN1 gene expression coding for fibronectin (FN), a mesenchymal marker, was observed in MDA-MB-436 and BT-20 cells and, to a lesser extent, in SW480 cells. These findings identified the EMT-inducing effects of TGF-β1, providing opportunities for further research to assess clinical implications. This study is part of a larger research project in which the expression of eight different EMT markers together with four house-keeping genes will be analysed in a total of eight BC and CRC cell lines, which have been treated with TGF-β1 and VPA and prepared for measurement and data collection as part of this study.