Despite great improvements in our understanding of ovarian cancer biology, this disease still ranks among the top five deadliest cancers in women. Mostly, it is due to (1) genetics of ovarian cancer varying enormously from patient to patient, which makes the treatment very challenging; and (2) the lack of shared among patients genomic mutations that are currently targetable. However, one genetic event, the mutation of p53 gene, is present in over 96% of ovarian cancer cases. Furthermore, mutation in p53 is frequently observed in ovarian cancer precursor lesions, suggesting that it is one of the first genomic alterations, which likely determine the fate of pre-cancerous cell. P53 is probably the most important anti-cancer gene (so called tumour suppressor) as it instructs cell to die or stop multiplying, when harmful DNA damage is detected. This cellular defence mechanism ensures survival of only healthy cells. Currently, there are no drugs specifically targeting mutant p53 and finding new inhibitors that can kill p53-mutant, but not p53-normal cells, would be critical for combating ovarian cancer without harming non-cancerous cells, which is often observed after chemotherapy. Also, this therapeutic strategy could be used to eliminate p53-mutated cells during early stages of disease development. There is a dire need to develop such a chemopreventive approach because symptoms of ovarian cancers often manifest themselves in the late stages, where survival prognosis is very low and the chance of recurrence is the highest. Since ovarian cancer lacks other genomic changes as frequent as p53 mutation, we propose to prioritize our research on identifying targetable vulnerabilities of p53-mutant ovarian cancer precursor cells and cancer cell lines to find new ways of fighting this deadly disease.
For this purpose, I have designed a screen utilizing genome editing technology to delete all human genes (almost 20,000) in normal fallopian tube epithelial cells, while making sure that only one gene is deleted per cell (AIM 1). Using DNA sequencing I will identify genes, which deletion cause cell death, since DNA of those cells will be reduced compared to DNA of cells that survive. Because this experiment will be performed in p53-normal versus mutant cells, I will be able to identify specifically what genes are necessary for survival of p53-mutant cells. Later, I will determine the mechanism, by which the deletion of these genes eliminate p53-mutant cells (AIM2). Also, I will treat precursor cells with commercially available pharmacological inhibitors specific for selected targets to evaluate their therapeutic potential. Cancer cell lines will be additionally treated with a combination of inhibitor and chemotherapeutic agent to identify putative synergistic effect in killing cancer cells. I will be mentored by the renowned specialists in ovarian cancer genetics, Dr. Simon Gayther, and functional genomics, Dr. Simon Knott, to ensure a success of this project.