Ovarian cancer (OC) is the 9th most common cancer and the 9th most common cause of cancer-related death in women, with an overall 5-year survival of approximately 40%. In 2018, 295,414 new cases of OC were documented worldwide, 184,799 of which resulted in death (1). High-grade serous ovarian carcinoma (HGSOC) is the most common and deadliest subtype of epithelial ovarian cancer (EOC), accounting for 70-80% of OC deaths (2). Originating from premalignant lesions in the epithelium of the fallopian tubes, HGSOC is known for its important genomic instability (3). Aside from universal TP53 mutation, HGSOC has numerous aberrations that vary among different tumours (4). To this day, some murine models with specific mutations have been developed, which serve as representatives of some particular tumours. ID8 cells, derived from mouse ovarian surface epithelial cells, have been used for the creation of these new cell lines (5). Previous work conducted in the lab consisted of targeting mutations characteristic of HGSOC by CRISPR/Cas9 knockout as a means of creating more representative models. These included tumour suppressor Trp53, known to induce growth arrest or apoptosis; Brca2, another tumour suppressor that maintains the genomes stability by regulating the homologous recombination (HR) pathway for double-strand DNA (d
sDNA) repair; and Nf1 gene, a negative regulator of the RAS signal transduction pathway (6) (uniprot.org). Mutation of the TP53 gene is found in the majority of HGSOC patients (7), whereas both BRCA2 and NF1 mutations are found in around 20% of patients (8)(9). Results showed that Trp53-/-;Brca2-/- double mutant mice have longer survival following treatment with both platinum and PARP inhibitor compared to Trp53-/-;Brca1-/- and Trp53-/- mutants, but that survival of mice bearing mutations in Trp53 and Nf1 genes is reduced after platinum treatment compared to Trp53-/- mice, along with higher intra-tumoural growth due to prolonged activation of the RAS/RAF/MAPK signalling pathway (6). Surprisingly, 50% of HGSOC patients harbouring BRCA2 mutation also present with a mutation in NF1 (8). Here we create a new murine ID8 Trp53-/-;Brca2-/-;Nf1-/- cell line to understand the consequences of Nf1 loss in ID8 Trp53-/-;Brca2-/- cells by CRISPR/Cas9 Nf1 knockout. We want to study the effect of the combined triple loss in cell doubling time in vitro, in the regulation of cell growth and survival pathways, and of response to platinum chemotherapy and PARP inhibition. We hypothesize that lack of Nf1 in ID8 Trp53-/-;Brca2-/- models will counteract to some extent the effect of Brca2 loss in cell growth and response to chemotherapy.