Objective    To study the influence of microenvironment created by dissoluble cytokines derived from hepatocellular carcinoma cells (HCCs) on the expression of IL-12 of dendritic cells (DCs) at different differentiating stage.     Methods    The CD14

+

monocytes

isol

ated with immune magnetic beads from fresh peripheral blood of healthy human

were cultured in RPMI 1640/10% FBS supplemented with 100 ng/ml rhGM-CSF and 100 ng/ml rhIL-4 for 7 d to develop into immature DCs (imDCs). Maturation was induced by addition of 20 ng/ml rhTNF-α to imDCs for another 3 days’ culture. Acquired imDCs and mDCs were respectively co-cultured with human HCC Bel7402 cells for 48 h in Transwell chamber. The concentrations of IL-10

IL-12

TGF-β

1

and VEGF in culture supernatant were investigated by ELISA

imDCs and mDCs cultured alone served as control.     Results    After co-cultured with Bel7402 cells

IL-12 were decreased from (115.076±8.129) pg/ml to (17.599±1.757) pg/ml in imDCs

and from (258.346±3.609) pg/ml to (6.787±1.123) pg/ml in mDCs (P0.05

P0.01). However

TGF-β

1

concentrations in culture supernatant were increased from (133.172±3.053) pg/ml to (633.025±9.527) pg/ml in imDCs

and from (174.446±3.972) pg/ml to (486.806±10.515) pg/ml in mDCs (P0.05

P0.01). VEGF concentrations was from 0 pg/ml to (830.892±7.564) pg/ml and (858.169±5.419) pg/ml in imDCs and mDCs respectively (P0.01).     Conclusion    HCCs inhibits secretion of IL-12 from DCs

which may be one of the ways which HCCs impair the immune regulatory function of DCs. 