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

Objective To further study the anti-metastasis mechanism of laminin-glycope ptides on carcinoma cell proliferation, apoptosis and the secretion of matr ix metalloproteinases. Methods Human hepatocellular carcinoma cells in serum free medium were incu bated on laminin-coated substrate with or without laminin-glycopeptides at a final concentration of 50 mu g/ml. The total number of surviving cells af ter incubating for the indicated time was assayed by MTT assay. DNA synthes is of the incubated cells was detected by H-3-TdR incorporation. Cell cycle was analysed by FAGS. The mitotic index of Giemsa stained cells was assess ed. Cell apoptosis was detected by both FAGS and an acridine orange stainin g method. Matrix metalloproteinase secretion was analysed by gelatin zymogr aphy. Results The total number of surviving cells incubated on laminin in the abs ence of laminin-glycopeptides was significantly larger than that in the pre sence of laminin-glycopeptides. Laminin promoted (3) H-TdR incorporation of carcinoma cells, decreased the percentage of cells in G1 phase and increas ed the percentage of cells in S phase. In contrast, laminin-glycopeptides c ould inhibit the effect of laminin as shown by H-3-TdR incorporation and ce ll cycle analysis. The percentage of cells in G2 + M phase and the mitotic index among various groups showed no significant difference. Matrix metallo proteinases 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-glycopep tides could significantly inhibit the effect of laminin by inhibiting DNA s ynthesis and arresting the carcinoma cell cycle from G1 to S phase. These e ffects 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 carcinom a 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.