High Grade Serous Ovarian Carcinoma (HGSOC) is the most common and aggressive subtype of epithelial ovarian cancer and is associated with late stage presentation and poor survival. Development of a genetically engineered mouse model (GEMM) of HGSOC is essential for a deeper understanding of the disease, however is associated with significant time, expense and can be challenging to validate. Supplementing GEMM with 3D organoid culture is an attractive option for validation and the development of more robust models. Here, we present a GEMM targeting the hypothesised cell of origin in HGSOC, the PAX8 positive fallopian tube secretory epithelial cell (FTSEC).
This GEMM attempts to emulate alterations seen in the aggressive C5 molecular subtype of HGSOC by directing over-expression of MYCN and mutant P53 to the PAX8 positive FTSEC, regulated by doxycycline. Analysis of mRNA expression confirmed transgene activation. Dissection and 60 minute pronase digestion of fallopian tubes, followed by overnight seeding on a layer of matrigel to remove debris resulted in viable, healthy cells that were seeded on day 2 into multiple 15uL matrigel domes in a specialised media. Analysis of growth, morphology, and PAX8 expression (determined by immunohistochemistry of cytospun cells) on days 4, 8 and 12 demonstrated that transgenic cultures have a growth advantage compared to wild type cultures and are enriched for PAX8 positive cells. Propagation of organoids yields robust material for further genetic manipulation by CRISPR/CAS9 nucleofection.
We have generated an organoid model of transgenic FTSECs suitable for additional validation and manipulation enabling development of a robust transgenic model of HGSOC.