Preventing Surgery-Induced NK Cell Dysfunction Using Anti-TGF-β Immunotherapeutics

Natural Killer (NK) cell cytotoxicity and interferon-gamma (IFN gamma) production are profoundly suppressed postoperatively. This dysfunction is associated with increased morbidity and cancer recurrence. NK activity depends on the integration of activating and inhibitory signals, which may be modulated by transforming growth factor-beta (TGF-beta). We hypothesized that impaired postoperative NK cell IFN gamma production is due to altered signaling pathways caused by postoperative TGF-beta. NK cell receptor expression, downstream phosphorylated targets, and IFN gamma production were assessed using peripheral blood mononuclear cells (PBMCs) from patients undergoing cancer surgery. Healthy NK cells were incubated in the presence of healthy/baseline/postoperative day (POD) 1 plasma and in the presence/absence of a TGF-beta-blocking monoclonal antibody (mAb) or the small molecule inhibitor (smi) SB525334. Single-cell RNA sequencing (scRNA-seq) was performed on PBMCs from six patients with colorectal cancer having surgery at baseline/on POD1. Intracellular IFN gamma, activating receptors (CD132, CD212, NKG2D, DNAM-1), and downstream target (STAT5, STAT4, p38 MAPK, S6) phosphorylation were significantly reduced on POD1. Furthermore, this dysfunction was phenocopied in healthy NK cells through incubation with rTGF-beta 1 or POD1 plasma and was prevented by the addition of anti-TGF-beta immunotherapeutics (anti-TGF-beta mAb or TGF-beta R smi). Targeted gene analysis revealed significant decreases in S6 and FKBP12, an increase in Shp-2, and a reduction in NK metabolism-associated transcripts on POD1. pSmad2/3 was increased and pS6 was reduced in response to rTGF-beta 1 on POD1, changes that were prevented by anti-TGF-beta immunotherapeutics. Together, these results suggest that both canonical and mTOR pathways downstream of TGF-beta mediate phenotypic changes that result in postoperative NK cell dysfunction.