Phagocytic and chemiluminescent activity of blood neutrophils in patients with bladder cancer

BACKGROUND: Tumor microenvironment modulates (including with the help of metabolites) the functional activity of the neutrophils that contribute to the reprogramming of the antitumor activity into a protumor one. AIMS: To study the phagocytic and chemiluminescent activity of neutrophils in patients with bladder cancer (BC) under the influence of metabolites of the tumor microenvironment in vitro. MATERIALS AND METHODS: We examined 37 patients with superficial BC (T1,а,isN0M0) and considered 32 healthy individuals as a control group. Neutrophils isolated from their blood were incubated in vitro with lactate, ADP, and glutamate. Phagocytic activity was examined using flow cytometry, and the intensity of the respiratory burst of neutrophils was evaluated via chemiluminescent analysis. RESULTS: In patients with BC, the phagocytic index (PhI) values are reduced compared to the control sample (without in vitro metabolite exposure) and when exposed to glutamate, while the effect of lactate on cells causes an increase in the phagocytic number and PhI. Moreover, under the influence of lactate in vitro, the activity of spontaneous and zymosan-induced chemiluminescence of neutrophils decreases. ADP causes a decrease in spontaneous chemiluminescence only. Finally, under the influence of glutamate, the indicators of spontaneous and induced chemiluminescence decrease. CONCLUSIONS: Under the influence of lactate and ADP (products of tumor cells), the phagocytic activity of a population of immature neutrophils is stimulated, which leads to myeloid suppressor cells that inhibit antitumor immunity. Thus, metabolites of the tumor microenvironment modulate the activity of the respiratory burst of neutrophils in patients with BC.