The mechanism of inhibition of metastasis by cartilage polysaccharide in breast-cancer cells.

As large amounts of porcine cartilage are discarded as waste in daily life, it is necessary to find new uses for them. We extracted polysaccharide from cartilage and performed in vitro and in vivo experiments in cancer cells. A mouse breast-cancer pulmonary metastasis model was set up, and we tried to determine the mechanism of the inhibition of metastasis by cartilage PS (polysaccharide). Effects on tumour size and the progression of metastasis indicated that cartilage PS can obviously inhibit metastasis in breast-cancer cells. The levels of LNR1 (laminin receptor 1), alphavbeta3 integrin and MMP-9 (matrix metalloproteinase-9) in mice treated or not with cartilage PS showed significant differences. Cartilage PS inhibited the growth of MCF-7 human breast adenocarcinoma cells, but had little effect on normal cells. Cartilage PS can inhibit the activity of the MMP-2 and the MMP-9 by decreasing the levels of LNR1 and alphavbeta3 integrin to inhibit metastasis further. In summary, we conclude that cartilage PS can act as a specific anti-metastatic agent in breast-cancer cells.