PO-134 Cytogenetic and molecular characterisation of new high-grade serous ovarian cancer cell line OVPA8

Abstract

IntroductionBladder cancer (BC) is the ninth most common cancer worldwide. A quarter of all cases present as muscle invasive BC (MIBC). Treatment for this group has remained largely unchanged for the past 20 years limited mainly to cisplatin based therapy and radical cystectomy. Prognosis for these patients is poor, with 5 year survival <50% and identification of potential new therapeutic approaches is urgently needed. We have explored the possible role of extracellular matrix protein 1 (ECM1) overexpression in MIBC. ECM1 overexpression has been linked to carcinogenesis and progression to a more aggressive phenotype in a number of carcinomas, but its role in BC has not yet been examined. In a previous study, ECM1 was proposed to interact with and stabilise EGFR in a breast cancer cell line leading to increased resistance to ERBB targeting drugs. Despite repeated implication of EGFR in the progression of BC, EGFR targeting agents have so far had little success in the treatment of MIBC in part due to resistance. Improved understanding of the mechanisms of resistance to such agents is vital. The current study examined ECM1 overexpression and the relationship between ECM1 and EGFR in BC.Material and methodsECM1 expression was assessed at the mRNA and protein levels in 47 bladder tumour derived cell lines using qRT-PCR and western blot analysis. ECM1 knockdown cell lines were established using shRNA lentiviral transduction in a panel of cell lines which overexpress the protein. ECM1 knockdown cell lines were analysed for phenotypic effects. Phosphorylation of EGFR and downstream effectors was examined following recombinant ECM1 treatment. Publicly available microarray data was mined to assess the clinical significance of ECM1 expression in patients, relating high expression to tumour stage and overall survival.Results and discussionsECM1 knockdown had an inhibitory effect on wound-healing ability. Evidence suggests ECM1 initiates phosphorylation and thus activation of EGFR and downstream effectors in the pathway, however we have been unable to detect a direct interaction with EGFR as described in breast. Mining of publicly available data revealed a significant association between high ECM1 expression and reduced overall survival.ConclusionECM1 overexpression in MIBC appears to be associated with poorer prognosis in patients. While ECM1 has been shown to influence EGFR signalling, the mechanism of EGFR activation by ECM1 in BC may be different from that previously described in breast cancer.