Nivedha Murali Shankar (Dresden/ DE), Paola Ortiz Montero (Dresden/ DE), Anastasia Kurzyukova (Dresden/ DE), Franziska Knopf (Dresden/ DE), Dr. Jiri Eitler (Dresden/ DE), Prof. Dr. Torsten Tonn (Dresden/ DE)
Background
NK cells are attractive effectors for adoptive immunotherapy of cancer. Results from first-in-human studies with chimeric antigen receptor (CAR)-engineered primary NK cells and NK-92 cells are encouraging in terms of efficacy and safety.
Methods
To further improve treatment strategies and to test the efficacy of CAR-NK cells in a personalized manner, high-throughput preclinical screening assays using patient-derived tumor samples are needed. Here, we established a flexible Danio rerio (zebrafish) larvae in vivo xenograft model and tested the efficacy of PD-L1-targeting CAR NK-92 cells (PD-L1.CAR NK-92) against the PD-L1-expressing breast cancer cell line MDA-MB-231. In addition, we used transgenic zebrafish models with labeled blood vessels to study CAR-NK migration in the vasculature.
Results
We have shown that MDA-MB-231 GFP cells injected into zebrafish larvae at 2 days post fertilization (dpf) are viable and migrate to peripheral parts of the zebrafish body, including the tail region. PD-L1.CAR NK-92 cells injected 2.5 hours later could also migrate to the zebrafish periphery and eliminate cancer cells throughout the body as early as 24 hours, in contrast to parental NK-92 or uninjected controls. Residual cancer cells were further eliminated at later time points, with 48 hours post-injection (hpi) being the best time point for analysis. Confocal live-cell imaging in vivo demonstrated intravascular migration and real-time interaction of PD-L1.CAR NK-92 with MDA-MB-231 cells, resulting in cytotoxicity.
Conclusion
Our data thus suggest that zebrafish larvae can be used for rapid assessment of CAR-NK cell potency in vivo to predict patient response to therapy.
Offenlegung Interessenkonflikt:
The authors declare that they have no competing interests.