Journal: Journal for Immunotherapy of Cancer
Article Title: PD-L1 targeting high-affinity NK (t-haNK) cells induce direct antitumor effects and target suppressive MDSC populations
doi: 10.1136/jitc-2019-000450
Figure Lengend Snippet: PD-L1 silencing on MDA-MB-231 diminished the ability of PD-L1 t-haNK cells to target the tumor cells in vitro. PD-L1 null MDA-MB-231 was generated through the CRISPR/Cas9 system. PD-L1 knockout was confirmed via (A) flow cytometry, (B) western blot, and (C) immunofluorescence microscopy. Scale bar=75 µm (D). WT MDA-MB-231 and PD-L1 null MDA-MB-231 tumor cell lysis mediated by PD-L1 t-haNK cells was evaluated via 111 In-release assay at different E:T ratios. (E) WT MDA-MB-231 and PD-L1 null MDA-MB-231 tumor cell lysis mediated by PD-L1 t-haNK and haNK cells were evaluated via 111 In-release assay at 50:1 E:T ratio. Results for via 111 In-release assay shown are the means with SEM of triplicate measurement and representative of two independent experiments. (F) CFSE-labeled WT MDA-MB-231 and CellTrace Violet-labeled PD-L1 null MDA-MB-231 were cocultured together and added with irradiated PD-L1 t-haNK cells at different E:T:T ratios overnight before flow cytometric analysis of cell lysis. The FACS plots shown have been stratified to live cells and downsampled such that each plot has the same cell count in each E:T:T ratio. The numbers indicate the cell count for each population in the downsampled plots. Data are representative of two independent experiments for each cell line. Two-way analysis of variance with Sidak’s multiple comparison test was used for statistical analyses. **P<0.01, ***P=0.09, ****P < 0.0001. E:T, effector to target; PD-L1, programmed death-ligand 1; CFSE, carboxyfluoresceinsuccinimidyl ester; DAPI,4′,6-diamidino-2-phenylindole; ns, not significant; t-haNK, targeting high-affinity natural killer; WT, wild type.
Article Snippet: An ongoing phase I monotherapy study in patients with locally advanced or metastatic solid tumor malignancies (NantKwest sponsored) will evaluate the overall safety profile of PD-L1 t-haNK cells and will provide dosing and safety data required for subsequent clinical studies.
Techniques: In Vitro, Generated, CRISPR, Knock-Out, Flow Cytometry, Western Blot, Immunofluorescence, Microscopy, Lysis, Release Assay, Labeling, Irradiation, Cell Counting