There is intense interest in developing novel approaches to enhance immune-mediated cancer therapies with cells such as Natural Killer (NK) cells. Previously, a particle-based method was developed for in vitro expansion of highly cytotoxic human NK cells (PM21-NK cells). Here, we tested two approaches to further enhance the antitumor activity of PM21-NK cells. First, we tested the hypothesis that oncolytic Parainfluenza virus 5 (P/V virus) would combine with PM21-NK cells for enhanced killing of lung cancer cells in vitro. Flow cytometry, luminescence and real-time imaging-based methods were used to assay PM21-NK cell-mediated killing of P/V virus-infected lung cancer cells in 2-dimensional (2D) and 3-dimensional (3D) spheroid cultures. In 2D cultures, lung cancer cells were efficiently infected by the P/V virus and PM21-NK cell killing activity was enhanced against P/V virus-infected cancer cells compared to non-infected cells. By contrast, P/V virus infection of 3D lung cancer cell spheroids was restricted to only the outer-most layer of cells. Nevertheless, PM21-NK cells showed enhanced killing in both infected and non-infected spheroid cells. Antibody neutralization assays showed enhanced NK cell killing was due to both type I and III interferon signaling in lung cancer target cells, which increased their killing by PM21-NK cells. In a second approach to enhance NK cell anti-tumor activity, we designed a novel chimeric protein (NA-Fc) which positions an IgG Fc domain on the plasma membrane, mimicking the orientation of IgG bound to the cell surface. Real time viability assays revealed that stable expression or lentiviral delivery of NA-Fc to A549 and H1299 lung, SKOV3 ovarian and A375 melanoma cancer cells increased their killing in vitro by PM21-NK cells, and this depended on CD16-Fc interactions. Our results lay the foundation for further development of oncolytic viruses and/or novel Fc-based molecules to deliver signals for enhanced NK cell mediated anti-cancer therapies.
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Doctor of Philosophy (Ph.D.)
College of Medicine
Burnett School of Biomedical Sciences
Length of Campus-only Access
Doctoral Dissertation (Campus-only Access)
Varudkar, Namita, "Virus Mediated Delivery of Signals to Enhance NK Cell Mediated Killing of Tumor Cells" (2022). Electronic Theses and Dissertations, 2020-. 1492.
Restricted to the UCF community until 11-15-2027; it will then be open access.