American Association for Cancer Research
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Supplementary figures 2-4 from CRISPR/Cas9-Mediated Trp53 and Brca2 Knockout to Generate Improved Murine Models of Ovarian High-Grade Serous Carcinoma

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posted on 2023-03-31, 00:08 authored by Josephine Walton, Julianna Blagih, Darren Ennis, Elaine Leung, Suzanne Dowson, Malcolm Farquharson, Laura A. Tookman, Clare Orange, Dimitris Athineos, Susan Mason, David Stevenson, Karen Blyth, Douglas Strathdee, Frances R. Balkwill, Karen Vousden, Michelle Lockley, Iain A. McNeish

Figures S2-S4: Transcription of Cdkn1a in CRISPR control clones; Sanger sequencing of Brca2 exon 3; RAD51 focus formation following irradiation


University of Glasgow and Cancer Research UK



There is a need for transplantable murine models of ovarian high-grade serous carcinoma (HGSC) with regard to mutations in the human disease to assist investigations of the relationships between tumor genotype, chemotherapy response, and immune microenvironment. In addressing this need, we performed whole-exome sequencing of ID8, the most widely used transplantable model of ovarian cancer, covering 194,000 exomes at a mean depth of 400× with 90% exons sequenced >50×. We found no functional mutations in genes characteristic of HGSC (Trp53, Brca1, Brca2, Nf1, and Rb1), and p53 remained transcriptionally active. Homologous recombination in ID8 remained intact in functional assays. Further, we found no mutations typical of clear cell carcinoma (Arid1a, Pik3ca), low-grade serous carcinoma (Braf), endometrioid (Ctnnb1), or mucinous (Kras) carcinomas. Using CRISPR/Cas9 gene editing, we modeled HGSC by generating novel ID8 derivatives that harbored single (Trp53–/–) or double (Trp53–/–;Brca2–/–) suppressor gene deletions. In these mutants, loss of p53 alone was sufficient to increase the growth rate of orthotopic tumors with significant effects observed on the immune microenvironment. Specifically, p53 loss increased expression of the myeloid attractant CCL2 and promoted the infiltration of immunosuppressive myeloid cell populations into primary tumors and their ascites. In Trp53–/–;Brca2–/– mutant cells, we documented a relative increase in sensitivity to the PARP inhibitor rucaparib and slower orthotopic tumor growth compared with Trp53–/– cells, with an appearance of intratumoral tertiary lymphoid structures rich in CD3+ T cells. This work validates new CRISPR-generated models of HGSC to investigate its biology and promote mechanism-based therapeutics discovery. Cancer Res; 76(20); 6118–29. ©2016 AACR.