GSK3 Inhibition Drives Maturation of NK Cells and Enhances Their Antitumor Activity

Abstract

Maturation of human natural killer cells (NK cells) as defined by accumulation of cell surface expression of CD57 is associated with increased cytotoxic character and TNF and IFN-γ production upon target cell recognition. Notably, multiple studies point to a unique role for CD57+ NK cells in cancer immunosurveillance, yet there is scant information about how they mature. In this study, we show that pharmacological inhibition of GSK3 kinase in peripheral blood NK cells expanded ex vivo with IL-15 greatly enhances CD57 upregulation and late-stage maturation. GSK3 inhibition elevated the expression of several transcription factors associated with late-stage NK cell maturation including T-BET, ZEB2 and BLIMP-1 without affecting viability or proliferation. When exposed to human cancer cells, NK cell expanded ex vivo in the presence of a GSK3 inhibitor exhibited significantly higher production of TNF and IFN-γ, elevated natural cytotoxicity, and increased antibody-dependent cellular cytotoxicity (ADCC). In an established mouse xenograft model of ovarian cancer, adoptive transfer of NK cells conditioned in the same way also displayed more robust and durable tumor control. Our findings show how GSK3 kinase inhibition can greatly enhance the mature character of NK cells most desired for effective cancer immunotherapy.

T‐bet and Eomes govern differentiation and function of mouse and human NK cells and ILC1

“…The GSK3 kinase may also control T-bet expression in NK cells. Indeed, pharmacological inhibition of GS3K induces an increase in T-bet, Zeb2, and Blimp1 expression in NK cells and greatly enhances their effector functions and anti-tumor potential [132]. A similar effect was observed in CD8 T cells upon combined blockade of CTLA-4, PD-1, and Lag-3 [133].…”

Natural Killer Cells in Cancer Immunotherapy

“…More attention should be devoted to developing products with defined functional characteristics. Focusing on the functional attributes of adaptive NK cells, Cichocki et al (2017) discovered that adding a small-molecule inhibitor of glycogen synthase kinase 3 to peripheral blood NK cells from a CMV-seropositive donor expanded ex vivo with IL-15 for one week resulted in an enriched population of adaptive CD57 + NKG2C ++ NK cells. This outcome was linked to the expression of several transcription factors associated with late-stage NK cell maturation, including T-BET, ZEB2, and BLIMP-1, without affecting cell viability or proliferation.…”

The CD56bright CD62L+ NKG2A+ immature cell subset is dominantly expanded in human cytokine-induced memory-like NK cells

“…These KIR + NKG2C + CD57 + highly cytotoxic and mature NK cells are selectively expanded from CMV+ donor NK cell. Mature, adaptive NK cells do not proliferate well, instead immature NK cells were maturated using a pharmacological inhibitor of GSK3β kinase (Cichocki et al, 2017). Otherwise, NKG2C + NK cells are selectively activated and expanded using human HLA-E expressing feeder cells (Liu et al, 2017).…”