Abstract A10: A mutagenesis screen identifies tumor suppressors and kinases as potential driver genes of ovarian cancer
Authors: Colvin Emily K. , Fuller Emily , Cheng Jizhou , Gill Anthony , Marsh Deborah J. , Howell Viive M. 
Published: August 2014

Background: The goal of this project is to increase our understanding of the molecular aetiology of ovarian cancer by utilizing Sleeping Beauty (SB) insertional mutagenesis.

Methods: Breeding colonies of the following genetically engineered mice were established and cross bred: homozygous floxed SB (STOCK Rosa26-LsL-D-SB11;T2/Onc2,TG6113), homozygous floxed Brca1 knock-out (C57BL/6.Brca1tm2Brn) and Tp53 mutant (C57BL/6-Trp53tm1Tyj/J). CRE recombinase packaged into an adenoviral vector (AdCreM2, MicroBix Biosystems Inc, CA) was surgically injected under the ovarian bursal membrane of mature female mice to delete Brca1 and activate SB mutagenesis in the ovarian surface epithelium. Mice were monitored and sacrificed at ethically defined endpoints or a maximum of 15 months post-surgery. Tumors were assessed for SB transposase activity by immunohistochemical staining. DNA was extracted from paraffin embedded sections of ovarian tumors and underwent high-throughput sequencing for T2/Onc2 insertion sites (Illumina, University of Iowa). Genes with insertion sites were interrogated against SEOC data from The Cancer Genome Atlas (TCGA) to identify genes also altered in the human malignancy. Functional annotation clustering was performed using DAVID (Database for Annotation, Visualization and Integrated Discovery, v6.7).

Results: Ovarian tumors were observed at low penetrance starting at 30 weeks post-surgery in SBflox/+Tp53mut/+ mice (6%, 3/48) and SBflox/+Brca1flox/flox p53mut/+ mice (8%, 4/50). No ovarian tumors were observed in SBflox/+Brca1flox/flox mice (n=38) or in SBflox/+Brca1flox/+ mice (n=26). Sequencing of the insertion sites identified a number of genes of which 67 were altered in 10 - 30% of cases in the TCGA SEOC dataset (N = 316). This gene-set was enriched for kinases (P = 0.003, False discovery rate (FDR) = 3%) including Fgfr2, Dyrk1a and Gsk3b, and small GTPase regulators (P = 0.01, FDR = 11%) including Smap2, Trio and Dock10. Other genes of interest included tumor suppressor genes Arid1b, Cdh4 and Wwox and the E3 ubiquitin ligase Ube3a. In the TCGA dataset, decreased progression free survival was associated with high expression of GSK3B, TRIO and UBE3A and low expression of WWOX.

Conclusions: This screen identified a number of novel potential driver genes of ovarian cancer. In addition genes previously associated with ovarian cancer were also identified, providing proof of principle for this approach. Investigation of these novel genes may lead to further insights into the pathogenesis of ovarian cancer.

This work was supported by Cancer Institute NSW, Cancer Council NSW and The Northern Translational Cancer Research Unit, NSW, Australia.

Citation Format: Emily K. Colvin, Emily Fuller, Jizhou Cheng, Anthony Gill, Deborah J. Marsh, Viive M. Howell. A mutagenesis screen identifies tumor suppressors and kinases as potential driver genes of ovarian cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr A10.