Aim: To investigate the effect of reactive oxygen species on the proliferation of lymphokine-activated killer (LAK) cells in patients with bladder cancer and their cytolysis to bladder tumor cells.
Methods: Sodium nitroprusside (SNP) was used as nitric oxide (NO) donor. The superoxide anion (O2-.) was generated in the complete medium (CM) supplemented with N-methylphenazonium methyl sulfate (PMS) 3-120 micromol/L and nicotinamide adenine dinucleotide (NADH) 18 - 600 micromol/L. The hydroxyl radical (.OH) was produced by adding ascorbic acid (AA) 0.5 - 400 micromol/L and ferrous sulfate (Fe2+) 0.05 - 40 micromol/L in CM. LAK cell proliferation and cytotoxicity were assayed in the presence of NO, .OH, or O2-. Bladder cancer cell lines BIU-87 and EJ were cultured as target cells and cytotoxicity of LAK cells were determined by MTT assay.
Results: The proliferation of LAK cells induced by interleukin-2 (IL-2) was inhibited by hydroxyl radical from 48 h to 96 h in a dose-dependent fashion and was inhibited to 34.5 % compared with control at 96 h in the concentration of ascorbic acid 400 micromol/L and ferrous sulfate 40 micromol/L. The inhibition induced by.OH can be overcome by certain concentrations of mannitol or editic acid. On the contrary, the proliferation of LAK cells induced by IL-2 was stimulated by certain concentrations of NO or O2-. The stimulation induced by O2-. can be overcome to control level by superoxide dismutase (SOD) 3 10(5) U/L. Exogenous O2-. resulted in an increase in cytotoxicity of LAK cells against BIU87 and EJ cells. However, the LAK cells cytotoxicity treated with hydroxyl radical or SOD showed no difference as compared with the control.
Conclusion: NO and O2-. enhanced the proliferation and activation and O2-. up-regulated antitumor cytotoxicity of LAK cells in patients with bladder cancer. The growth of LAK cells induced by IL-2 was down-regulated by hydroxyl radical. The effects of these reactive oxygen species on the proliferation of LAK cells induced by IL-2 were different.