We have previously reported that the expression of matrix metalloproteinase-9 (MMP-9), membrane type-1 matrix metalloproteinase (MT1-MMP) and β1 integrins in murine hepatocellular carcinoma (HCC) was associated with the occurrence of intrahepatic metastasis, which is considered to be a major modality in recurrence. Here we show that intravenous administration of synthetic RGD pseudo-peptide (FC-336) inhibited intrahepatic metastasis produced by orthotopic implantation of a fragment of murine HCC (CBO140C12) tumor as compared with control administration of vehicle (p<0.05), but did not affect the growth of the implanted tumor. To further analyze the anti-metastatic effect of FC-336, we investigated the effects of FC-336 on tumor growth, adhesion and invasion in vitro. FC-336 at non-cytotoxic concentration of less than 5 mg/ml effectively inhibited the adhesion and invasion of CBO140C12 cells (p<0.05). We also used zymography to examine the effect of FC-336 on the gelatinolysis of MMPs produced by CBO140C12 cells. FC-336 inhibited the degradation of the gelatin substrate by MMP-9 in a concentration-dependent manner. These results strongly suggest that intrahepatic metastasis of CBO140C12 tumors is partly due to the marked invasive and adhesive abilities of tumor cells mediated by expression of MMP-9 and integrin α3β1 (VLA-3), integrin α5β1 (VLA-5) on the tumor surface, respectively.

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