Effects of laminin glycopeptides on metastasis-related behaviors of cancer cells

Our previous reports have shown that lamininglycopeptides (LN-GPs), the total glycopeptides prepared from laminin (LN), can prevent the experimental lung metastasis and liver metastasis of mouse cancer cells. In order to explore the anti-metastatic mechanism of LNGPs, we studied the effects of LN-GPs on metastasisrelated behaviors of cancer cells in vitro. LN-GPs did not affect cell survival. However, LN-GPs inhibited cell attachment and spreading Of 5180 cells on LN- and Matrigelsubstrate in dose-dependent and time-dependent manners. Moreover, inhibition of cen attachment and spreading on Matrigel substrates were much greater on Matrigel substrate than on LN substrate. In the presence of LN-GPs, 5180 cells on LN substrate changed from a flattened polygonal shape to a round one, the migration of 5180 cells on LN substrate decreased, and the number of a highly invasive human pulmonary giant caxcinoma PG cells invading Matrigel filter in a Boyden chamber was reduced. LN-GPs thus have multiple inhibitory effects on cancer motastasisrelated behaviors.

The cellular and molecular mechanism of laminin glycopeptides on anti -metastasis

To further study the anti metastasis mechanism of laminin glycopeptides on carcinoma cell proliferation, apoptosis and the secretion of matrix metalloproteinases Methods Human hepatocellular carcinoma cells in serum free medium were incubated on laminin coated substrate with or without laminin glycopeptides at a final concentration of 50?μg/ml The total number of surviving cells after incubating for the indicated time was assayed by MTT assay DNA synthesis of the incubated cells was detected by 3H TdR incorporation Cell cycle was analysed by FACS The mitotic index of Giemsa stained cells was assessed Cell apoptosis was detected by both FACS and an acridine orange staining method Matrix metalloproteinase secretion was analysed by gelatin zymography Results The total number of surviving cells incubated on laminin in the absence of laminin glycopeptides was significantly larger than that in the presence of laminin glycopeptides Laminin promoted 3H TdR incorporation of carcinoma cells, decreased the percentage of cells in G1 phase and increased the percentage of cells in S phase In contrast, laminin glycopeptides could inhibit the effect of laminin as shown by 3H TdR incorporation and cell cycle analysis The percentage of cells in G2+M phase and the mitotic index among various groups showed no significant difference Matrix metalloproteinases secretion from cells treated by laminin glycopeptides was much less compared to that without the treatment by laminin glycopeptides Conclusion Laminin may stimulate cell proliferation, while laminin glycopeptides could significantly inhibit the effect of laminin by inhibiting DNA synthesis and arresting the carcinoma cell cycle from G1 to S phase These effects may inhibit not only tumor growth of the primary carcinoma, but also the establishment of metastases at ectopic tissues Laminin glycopeptides could also inhibit the secretion of matrix metalloproteinases from carcinoma cells and this may contribute to their decreased invasive and metastatic phenotype This study further revealed the cellular and molecular mechanism of laminin glycopeptides on anti metastasis