OBJECTIVETo investigate the role of CCL28 in hypoxia-induced cell migration of hepatocellular carcinoma (HCC).

METHODSResected liver tissues from 50 HCC patients were subjected to real-time (rt)-PCR analysis to evaluate the mRNA expression levels of the hypoxia-induced factor HIF-1a and the chemokine CCL28. Patient data on treatment and outcome were analyzed. The human HCC cell lines HepG2 and HCCLM3 were used to investigate effects of hypoxic conditions on HIF-1a and CCL28 expressions by rt-PCR, western blotting, and enzyme-linked immunoassay. The CCL28-mediated effects of hypoxic conditions on cell mobility and invasion were assessed by trans-well and matrigel assays, respectively, in HCCLM3 with CCL28 expression silenced by small-interfering (si)RNA transfection. Spearman's rank test was used to assess the correlation between CCL28 and effects on disease- and treatment-related factors.

RESULTSThe mRNA levels of CCL28 (0.025 +/- 0.075) were found to be strongly correlated with HIF-1a(0.065 +/- 0.098) in human clinical samples of HCC (r = 0.595, P less than 0.01), with higher expressions of both related to recurrence after surgery (P = 0.011 and 0.019, respectively). In vitro hypoxic conditions stimulated HIF-1a and CCL28 expression in a time-dependent manner in both HepG2 (HIF-1a: F = 873.5; CCL28: F = 151.6) and HCCLM3 (HIF-1a: F = 964.5; CCL28: F = 285.8) (all P less than 0.01). siRNA inhibition of CCL28 in HCCLM3 cells led to a significant reduction in hypoxia-induced invasion and migration (all P = 0.011).

CONCLUSIONChemokine CCL28 expression is up-regulated in human HCC and under in vitro hypoxic conditions, and may play an important role in hypoxia-induced HCC migration and invasion.