Genetically Defined, Syngeneic Organoid Platform for Developing Combination Therapies for Ovarian Cancer

Abstract

SUMMARYThe 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 mutational combinations seen in patients. Detailed analysis of homologous recombination (HR)-proficient (Tp53-/-;Ccne1OE;Akt2OE; KrasOE), HR-deficient (Tp53-/-;Brca1-/-;MycOE) and unclassified (Tp53-/-;Pten-/-;Nf1-/-) organoids revealed differences in in vitro properties and tumorigenicity. Tumorigenic organoids had variable 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.HIGHLIGHTSOrthotopic injection of genetically defined fallopian tube organoids yield HGSOC.Ovarian tumors with different genotypes evoke distinct immune microenvironmentsCombining Gemcitabine, anti-PD-L1, and anti-CTLA-4 result in complete responses in Tp53-/-;Ccne1OE;Akt2OE;KrasOE organoid-derived HGSOCTherapeutic response is tumor genotype-specific

Senescence induction dictates response to chemo- and immunotherapy in preclinical models of ovarian cancer

“…By incorporating MYC overexpression and Brca1 disruption into the platform, we substantially accelerate tumor onset and enable modeling of clinically important HR-deficient tumors. Collectively, these approaches provide a powerful orthogonal system to ovarian cancer models produced from tumor-derived cell or organoid lines (15)(16)(17)(18)(19)(66)(67)(68).…”

“…Consequently, it is impractical to develop animal cohorts of sufficient size and genotypic diversity for rapid and rigorous mechanistic and preclinical studies. Recently, both patient and murine HGSOC organoid models covering a range of genomic configurations have been developed, which enable perturbations in vitro or following orthotopic transplantation in vivo (15)(16)(17)(18)(19). However, these systems also have limitations: the human models cannot be studied in the presence of the intact immune system and the murine models that employ in vitro transformed cells do not undergo immunoediting and lack other microenvironmental factors that shape tumor development in vivo (20,21).…”

Cellular models of development of ovarian high‐grade serous carcinoma: A review of cell of origin and mechanisms of carcinogenesis

“…153,154 Considering the tissue microenvironment and cell-environment interactions, 3D organoid culture, co-culture and other new cultural technologies that more closely simulate the in vivo environment will provide possibilities for more realistic research. 27,155,156 Finally, genetic-engineered mouse models would provide the closest genocopy and phenocopy to mimic tumorigenesis, tumour-microenvironment and immune response to HGSC. [20][21][22]27,82,119,[157][158][159][160][161][162]…”

Harnessing preclinical models for the interrogation of ovarian cancer

“…This feature is favorable for cancer modeling and oncogene validation [143,144]. In the field of OC research, Zhang S et al modeled the initiation of HGSOC in mouse fallopian tube epithelial (FTE) organoids by lentivirus transduction and/ or CRISPR/Cas9 mutagenesis [145]. More recently, exponential interest has been fostered in PDO co-clinical trials.…”