Effects of different concentrations of nitric oxide on liver cancer cell line HepG2 and peripheral blood mononuclear cells in indirect co-culture system

Objective To study the effects of different concentrations of nitric oxide (NO) on liver cancer cell line HepG2 and peripheral blood mononuclear cells (PBMC). Methods Different rates of PBMC/HepG2 and drugs were arranged to regulate the concentrations of NO. Activity changes of the two kinds of cells were measured in cells cultured alone and co-cultured, which were compared with control group. Results The activity of PBMCs in co-cultured system was harmed only when the concentration of NO was more than 120 μmol/L, however, the activity of HepG2 cells in co-cultured system was suppressed when the concentration of NO was less than that of control group or was more than 241 μmol/L; moreover, the activity of co-cultured HepG2 cells was higher than that of HepG2 cells cultured alone in different concentrations of NO. In co-cultured system, with the increase of PBMC/HepG2 ratio, the concentration of NO was decreased, but the activity of HepG2 cells was increased. Conclusions The results have shown that HepG2 cells are damaged by high or low concentration of NO, and PBMC are only damaged by high concentration of NO, however, the low concentration of NO has few influences on PBMC. Moreover, the indirect contact of PBMC can promote the growth of the HepG2 cells. Key words: Liver neoplasms; Co-culture; Nitric oxide; Immunotherapy