We have demonstrated anti-proliferation and anti-metastasis effects of both interferon-alpha and a histone deacetylase inhibitor, sodium butyrate, on human liver cancer cell lines. In this study, invasive ability of human liver cancer cell lines through the matrix-coated membrane was examined and inhibitory effect of interferon-alpha and sodium butyrate was investigated. Among six human liver cancer cell lines, HLE and HLF showed high invasive ability using the Matrigel invasion assay. This invasion ability was significantly inhibited by pretreatment of the cells with 1000 IU/ml of interferon-alpha or 2 mM of sodium butyrate. Gelatin zymography and the matrix metalloproteinase-2 and -9 activity assay showed that these two cell lines produce active- and pro-matrix metalloproteinase-2 and -9, and their activity was significantly reduced by pretreatment with both agents. Real-time quantitative reverse transcription-polymerase chain reaction showed decrease in matrix metalloproteinase-1 mRNA levels by pretreatment with both agents, but mRNA levels of tissue inhibitor of matrix metalloproteinase-1 and -2 were differently modulated by interferon-alpha and sodium butyrate. These results suggest that interferon-alpha and sodium butyrate reduce a chance of invasion and metastasis of human liver cancer cells by inhibiting matrix metalloproteinase activity, although its inhibitor is differently regulated.