Development of New Therapeutic Combinations for Ovarian Cancer Using Genetically Defined, Syngeneic Organoid Platform

The paucity of genetically informed, immune-competent tumor models impedes evaluation of conventional, targeted, and immune therapies. By engineering mouse fallopian tube (FT) organoids using lentiviral gene transduction and/or CRISPR/Cas9 mutagenesis, we generated multiple high grade serous ovarian carcinoma (HGSOC) models exhibiting combinations of mutations seen in patients. Detailed analysis of homologous recombination (HR)-proficient (Tp53-/-;Ccne1OE;Akt2OE ;KrasOE), HR-deficient (Tp53-/-;Brca1-/-;MycOE ) and unclassified (Tp53-/-;Pten-/-;Nf1-/-) examples revealed differences in in vitro properties and tumorigenicity/metastasis. Tumorigenic organoids had differential sensitivity to HGSOC chemotherapeutics and evoked distinct immune microenvironments. These findings enabled development of a chemotherapy/immunotherapy regimen that yielded durable, T-cell dependent responses in Tp53-/-;Ccne1OE;Akt2OE;Kras HGSOC; by contrast, Tp53-/-;Pten-/-;Nf1-/- tumors failed to respond. Genotype-informed, syngeneic organoid models could provide an improved platform for rapid evaluation of tumor biology and therapeutics. Overall design: mRNA profiles of 4 independent tumors derived from organoid injection of Tp53-/-;Ccne1OE;Akt2OE;KrasOE, Tp53-/-;Pten-/-;Nf1-/- and Tp53-/-;Brca1-/-;MycOE, respectively.