Whole genome multiparametric screening to identify modulators of epithelial-mesenchymal transition

Metastasis accounts for the majority of treatment-refractory cancers and the poor prognosis of the disease. The phenotypic transition of non-motile epithelial tumour cells to a migratory and invasive mesenchymal phenotype (epithelial mesenchymal transition; EMT) enables the escape of cancer cells from the primary tumor into the circulation. Morphological change from cobblestone to elongated and spindle-shaped is a primary feature of cells that have undergone this process. This transition is also marked by upregulation of vimentin, an intermediate filament found in mesenchymal cells. The reverse process, mesenchymal to epithelial transition (MET), enables disseminated mesenchymal-like cells to subsequently establish macrometastasis at secondary sites. The work presented in this thesis aims to identify factors and elucidate pathways modulating EMT/MET, especially in the context of bladder cancer. To achieve this, a high content screening assay using genome wide siRNA, miRNA and kinase inhibitor libraries was conducted using the TSU-Pr1-B1 bladder cancer cell line. Harnessing the multiparametric ability of the high content platform, I have used morphological change and a vimentin promoter-reporter system (Vimentin/dsRed), parameters that are responsive to alterations in cellular epithelial/mesenchymal state, as the readouts to decipher the effects of a given siRNA/miRNA/kinase inhibitor. Data integration of validated hits with cancer-related expression profile databases and other EMT-related screens has identified several known regulators of EMT as well as molecules that have not been previously implicated in this process. These mediators provide new insights on the regulation of EMT/MET and provide key data to design further studies to enhance our understanding of cancer metastasis.