Background: Phagocytes, such as macrophages and neutrophils, play an important role in host defense and migrate toward a focus of infection accompanied by inflammation. This phagocytes’ directional migration is altered by various kinds of cytokines and reactive oxygen species (ROS), however, the mechanism how the cells are influenced by the cytokines and ROS is unknown. Here we report the relationship between phagocytes’ chemotaxis and ROS.
Methods: Human myeloid leukemia PLB985 (WT PLB) cells and their mutant (X-CGD PLB) cells that defect the superoxide producing enzyme NADPH oxidase subunit gp91phox (NOX2) were used. After differentiation with 0.65% dimethylformamide (DMF), the maturation of the cells was evaluated by checking the expression of NADPH oxidase subunits expression and the chemotaxis of the cells towards fMLP was compared by utilizing TAXIScan method. In addition, as a representative of non-immune cells, BxPC3 cells (pancreatic cancer cells) were also used for chemotaxis assay with hydrogen peroxide.
Results: Both WT PLB and X-CGD PLB cells were differentiated to mature cells with 0.65% DMF and the expression of NADPH oxidase subunits was increased, however, mature X-CGD PLB cells showed more activation in chemotaxis than WT PLB cells. In non-immune BxPC3 cells, hydrogen peroxide suppressed the chemotaxis towards serum in a dose dependent manner.
Discussion: The data above indicate that ROS suppress the chemotaxis, both in myeloid cells and cancer cells. The mechanism that ROS inhibits phagocytes chemotaxis in detail is still unknown and needs to be elucidated.