Inhibition of lymphangiogenesis‐related properties of murine lymphatic endothelial cells and lymph node metastasis of lung cancer by the matrix metalloproteinase inhibitor MMI270

Based on a previous report on the effect of a matrix metalloproteinase (MMP) inhibitory compound, MMI270, in regulating tumor‐induced angiogenesis, as well as recent findings concerning functional correlations among tumor metastasis, angiogenesis and lymphangiogenesis, we investigated the anti‐metastatic efficacy of MMI270 in a murine model of lymph node metastasis of lung cancer, and analyzed whether this inhibitor could also regulate lymphangiogenesis‐related properties of murine lymphatic endothelial cells (LECs) and invasive properties of Lewis lung cancer (LLC) cells. The observation that MMI270 led to a significant decrease in the weight of tumor‐metastasized lymph nodes of mice led us to test its anti‐lymphangiogenic and anti‐invasive effects in vitro. Murine LECs were characterized by an in vitro tube formation assay, by semi‐quantitative RT‐PCR assay to examine the expression of mRNAs for flt‐4, Flk‐1, Tie‐1, Tie‐2, CD54/ICAM1, vWF, MMPs and uPA, and by western blotting to confirm the protein expression of flt‐4 and CD31/PECAM. This is the first report on the expression of MMP‐2, MMP‐9 and MT1‐MMP in murine LECs, as well as on the inhibition of their enzymatic activity, and of the invasive ability and tube‐forming property of LECs by an MMP inhibitor. Furthermore, MMI270 was shown to strongly inhibit the activity of MMP‐2 and ‐9 produced by LLC cells and the invasion of these cells through Matrigel. In summary, the present results indicate that MMI270, apart from its anti‐tumor angio‐genic application, might be useful as an anti‐metastatic drug, on the basis of its downregulatation of both the lymphangiogenesis‐related properties of LECs and the invasive properties of LLC cells in vitro. (Cancer Sci 2004; 95: 25–31)