Gene expression analysis of SJG6 CONTROL and NICD

Mutational landscape of Oral Squamous Cell Carcinoma (OSCC) is predominated by frequent inactivating mutations in EGF- like ligand binding domain of NOTCH1. However role of NOTCH1 signalling in tumorigenesis is highly context and cell type dependent. In this study, we investigated phenotypic effect of NOTCH1 mutations in primary line derived from OSCC biopsy. Based on gain-of-function assays in NOTCH1 mutant line we demonstrated regulation of cell behaviour and morphology, by NOTCH1 intracellular domain (NICD) leading to changes in cell proliferation, migration, clonal growth and differentiation. Importantly, overexpression of NICD results in upregulation of ETV7/TEL2 which negatively regulates SERPINE1 expression and confers malignant cells with less aggressive phenotype. Further knockdown of SERPINE1 expression simulated the phenotypes observed upon rescue of NICD. In accord with our cell-based model we observed strong correlation between NOTCH1, ETV7 and SERPINE1 expression in OSCC primary tumours indicating similar deregulated mechanisms during oral carcinogenesis. Overall this study suggests a tumour suppressive role of NOTCH1 in OSCC and highlights possible mechanisms leading to changes in cell behaviour and morphology in absence of NICD potentially by regulating TEL2 and SERPINE1 expression. A lentiviral system was used to restore active domain of NOTCH1 (NICD) in the SJG6 line carrying a truncating mutation (here-on referred to as SJG6 + NICD). Gene Expression Profiling of SJG6 CONTROL and SJG6 NICD was performed to delineate candidate gene/s clusters deregulated in response to NICD expression. Affymetrix one-color experiment,Organism: Human ,Affymetrix Human Gene 1.0 ST Array , Labeling kit: Affymetrix GeneChip Kit