Nonviral Genome Engineering of Natural Killer Cells for Enhanced Cancer Immunotherapy

Abstract

Despite their late discovery within the lymphocyte lineage, NK cells have exhibited distinctive features that distinguish them as crucial players alongside their B and T cell counterparts. Notably, their absence of major histocompatibility (MHC) molecules positions them ideally for off-the-shelf allogeneic therapy, both for a remarkedly shorter diagnosis-to-treatment timeframe and a lower manufacturing cost. Furthermore, clinical observations indicate that NK cells induce less graft-versus-host disease (GvHD), cytokine release syndrome, and neurotoxicity compared to T cells. Early allogeneic NK cell therapy trials underscored a near-perfect safety profile of NK cell-based therapies; however, the limited number of patients exhibiting partial or complete responses suggested suboptimal anti-tumor efficacy of unmodified NK cells. This observation has spurred researchers to explore genetic modifications of NK cells to fully unleash their therapeutic potentials. Initially thought to be intransigence to genetic modification, NK cell engineering in the early days has benefitted from the advancements of using viral vectors due to their superior engineering efficiencies, despite the inherent limitations such as restricted cargo capacity and the risk of viral mutagenesis. However, with CRISPR-based technologies made available over the past decade, significant strides have been made to enabled scientists to pivot towards non-viral methods for engineering NK cells. In summary, the evolution of NK cell therapies from their discovery to their current state highlights a trajectory of innovation aimed at optimizing their therapeutic efficacy and safety in clinical applications. Here, we summarized common non-viral strategies that are currently available for NK cell engineering in the first chapter. Moving forward into the second chapter, we applied those non-viral strategies with a special focus on using CRISPR-based base editing technology for gene mutations and disruptions and transposon systems for chimeric antigen receptor (CAR) integrations. In the last chapter, we shed lights on additional ongoing projects with novel non-viral NK engineering strategies. In the future, we will be focusing on fine tuning engineered CAR-NK cell for a better safety profile and further its application in solid tumors with improved homing strategies and exploring the use of modified CD16a in combination with monoclonal antibodies as an alternate for CAR-NK therapy.