Effects of Adenosine and Lactate Coexistence on NK92 Cell

Aims: This study aims to investigate the impact of lactate and adenosine, present in the tumor microenvironment (TME), on the immune cell immunity.

Methodology: Five groups included Adenosine concentration screening groups, L-lactic acid and Sodium L-lactate concentration groups, Adenosine + L-lactic acid and Adenosine + sodium L-lactate concentration groups were chosen to evaluate the NK92 cell functions. The proliferation ability and morphological observations of NK92 cells were assessed using a hemocytometer. The CCK-8 assay measured the inhibition of NK92 cell activity in the treatment group, while the crystal violet method evaluated the effect of NK92 cells on the killing ability of A549 cells.

Results: A concentration of 50 μM adenosine served as a reference for high adenosine experimental concentrations, demonstrating a significant impact on NK92 immune cells within the TME. The functional entity "lactic acid" revealed independent effects of lactate [La-] and hydrogen ions [H+]. Lactate enhanced cell viability but reduced NK92 cytotoxicity. Conversely, lactic acid containing hydrogen ions caused a sharp decrease in cell viability and cytotoxicity to tumor cells.

Conclusion: Elevated adenosine concentration and acidification of the tumor microenvironment significantly inhibit the ability of NK cells to kill tumor cells.