Introduction: High-grade serous carcinoma (HGSC)  is a heterogeneous tumor in which immune checkpoint blockade has shown little success; however the <15% of patients that respond demonstrate that HGSC can be sensitive to immune-mediated clearance. Recent findings emphasize that HGSC tumors with immune infiltration of natural killer (NK) cells showed improved overall survival making them an appealing target for immunotherapy. This study aims to evaluate the multifaceted abilities of NK cells while considering factors that can promote their recruitment and persistence in HGSC. 

Methods:  HGSC cell lines were selected for their unique expression of  NK cell ligands and mutation profiles (OVCAR-3, OVCAR-4, OVSAHO, OV4453, TOV1946). To assess NK cell infiltration and co-localization within HGSC, we are using an in vitro tumor model (T-SLICE) which promotes cell-driven biochemical gradients. Within T-SLICE, cell line spheroids are embedded atop a monolayer of uterine fibroblasts. To assess NK cell motility, we introduce NK cells isolated from healthy donors. Within, tumor cell viability, mitochondrial membrane potential, and proliferation are monitored in real time. Concurrently, donor NK cells are cocultured with cell lines and subjected to high-parameter flow cytometry for assessment of phenotypic changes in NK cell degranulation, activation, and ligand expression. 

Results: Together, preliminary data from spheroid and flow cytometry co-cultures show differences in NK cell motility and cytotoxicity as well as changes in receptor/ligand profiles in response to different HGSC cell lines.  T-SLICE experiments assessing NK cell migration are ongoing.

Conclusion: NK cell dynamics and activity differ as a function of their intrinsic setpoint and the features of HGSC. Investigating NK cell as an immunotherapy for HGSC should consider the impacts of a tumor’s biochemistry, which T-SLICE enables with continuous, real-time monitoring paired with high parameter flow cytometry.