Decreased expression of SERPINB1 correlates with tumor invasion and poor prognosis in hepatocellular carcinoma.

SERPINB1 (serine protease inhibitor, clade B, member1) is a member of the SERPINB family. Recent studies suggested that SERPINB1 may suppress the migration and invasion of lung and breast cancers. In this study, we investigated a possible involvement of SERPINB1 in the regulation of hepatocellular carcinoma metastasis (HCC). The expression of SERPINB1 was evaluated using western blot analysis in 8 paired fresh HCC specimens and immunohistochemistrical assay on 67 paraffin-embedded HCC slices. SERPINB1 was downregulated in HCC specimens and correlatively related with two clinicopathologic features of HCC, metastasis (P = 0.000) and vein invasion (P = 0.006). Univariate and multivariate survival analyses showed a lower level of SERPINB1 expression is associated with poor prognosis and clinical outcome (P = 0.001). In addition, small interfering RNA targeting SERPINB1 was used to knock down the expression of SERPINB1 in Huh7 and BEL-7404 cells. We showed that interference of SERPINB1 promoted migration and invasion of HCC cells, while cell proliferation was not affected. Finally, we observed an apparent increase in the level of active matrix metalloproteinase-2 (MMP2) after SERPINB1 knockdown, implying that SERPINB1 might participate in the regulation of HCC metastasis through modulating the activation of matrix metalloproteinases. Overall, our results suggested an inhibitory role of SERPINB1 in the migration and invasion of HCC, implying that SERPINB1 might be a potential prognostic indicator of HCC metastasis.