Functional and metabolic targeting of natural killer cells to solid tumors.

Background: The unique ability of NK cells to target cancer cells without antigen specificity makes them an attractive prospect for immunotherapy of solid tumors. However, the complexity of the tumor microenvironment (TME), particularly its heterogeneity and associated immunosuppressive properties, enables solid tumor cells to escape NK cell immune-surveillance by impairing their infiltration and cytotoxic functions. As a result, NK cells that have been able to infiltrate solid tumors are dysfunctional, exhausted and metabolically and functionally impaired. Understanding the status of NK cells in solid tumors and the interplay between the tumor-promoting functions of the TME and the immunometabolic reprogramming events that NK cells endure as a result is essential to developing approaches to improve the clinical outcome of NK cell-based immunotherapies against solid tumors.

Conclusions: In this review, we address the current knowledge on the presence and immunometabolic roles of NK cells in solid tumors as well as the strategies developed to restore NK cell activities in these conditions, with the ultimate goal of enhancing persistence, trafficking, cytotoxicity and metabolic functions.