Invasiveness of Hepatocellular Carcinoma Cell Lines: Contribution of Membrane-Type 1 Matrix Metalloproteinase

Abstract

Intrahepatic metastasis is one of the malignant features of hepatocellular carcinoma (HCC). Matrix metalloproteoinases (MMPs) and urokinase-type plasminogen activator (u-PA)/plasmin, are known to be associated with the invasive properties of various types of tumor cells. In this study, we examined which proteinases play a role in the metastatic invasion of human HCC cell lines. JHH-5 and JHH-6 cells constitutively expressed mRNAs for both membrane-type 1 matrix metalloproteinase (MT1-MMP) and u-PA and invaded through reconstituted MATRIGEL in vitro, whereas JHH-7 cells expressed u-PA mRNA but not MT1-MMP and did not invade. However, hepatocyte growth factor (HGF) induced MT1-MMP expression on the surface of JHH-7 cells and markedly increased invasiveness of JHH-7 in a concentration-dependent manner. Moreover, cleavage activity for pro-MMP-2 was induced in HGF-treated JHH7 cells. MMP inhibitor, rather than serine proteinase inhibitor, potently inhibited HCC cell invasion. Intrahepatic injection of HCC cell lines into athymic nude mice caused visible intrahepatic metastases in vivo. Moreover, JHH-7 tumors showed expression of MT1-MMP mRNA, while in vitro cultured JHH-7 cells did not. These findings suggest that MTi-MMP plays an important role in the invasive properties of HCC cells, and that HGF modifies the invasive properties of noninvasive HCC cells.

Keywords

• hepatocellular carcinoma
• invasion
• intrahepatic metastasis
• MT1-MMP
• HGF