Abstract: Background We have completed canine immunotherapy trials using overlapping but distinct methods to target natural killer (NK) cells in dogs with naturally occurring cancer. High-throughput single-cell (sc)RNASeq allows the profiling of individual cell subtypes to thoroughly examine transcriptomic changes in clinical samples.
Hypothesis/Objectives Our objective was to investigate changes in NK cell populations in response to immunotherapy treatment and compare gene expression profiles between dogs receiving two separate NK-targeting treatments.
Animals Samples were available for five dogs treated for cancer at UC Davis (UCD, n=1) and University of Wisconsin (UW, n=4) in IACUC-approved pilot trials.
Methods The UCD cohort underwent palliative radiotherapy (RT) in addition to allogeneic NK cell transfer. Dogs in the UW cohort received low-dose molecular targeted radionuclide therapy (MTRT) with intratumoral injection of IL-2 fusion cytokine. Single-cell (sc)RNASeq was performed on isolated PBMCs before, during, and following treatment.
Results During and following treatment with RT and allogeneic transfer, NK cells retained robust expression of NK activating and functional genes, including KLRD1, GZMB, KLRA1, and NCR3. Dogs receiving MTRT therapy had increased expression of activation markers, such as CD69 and KLRK1, in post-treatment NK cells compared to pretreatment. Notably, the MTRT therapy-specific NK gene activation signature was similar across patients receiving the same treatment.
Conclusions and clinical importance This scRNASeq analysis provides insight into the diverse mechanisms of NK activation and serves as a basis for investigating innovative therapeutic combinations to improve cancer treatment and survival in canine patients.
