G(M3) has some important roles in cell-to-cell interaction and has proved to have an optimal concentration for fibronectin mediated cell adhesion. G(M3) content in murine bladder tumor (MBT-2) assessed by thin-layer chromatography was similar to human invasive bladder tumor. From glycolipid composition also, MBT-2 is considered as an appropriate model for human invasive bladder tumor. Anti-tumor effect of locally administered G(M3) On MBT-2 tumor was investigated. MBT-2 cells were injected subcutaneously into the right hind limb of CH3/HeSlc female mice on day 1. Tumor bearing mice were randomly placed on day 8 into G(M3) treatment, G(D3) treament, sialic acid treament and control groups. G(M3) was administered between tumor and fascia at 10 mu g in 0.1 ml, 1 mu g in 0.1 ml from day 8 to day 20 every other day, 7 times in total. Control group was given 0.1 mi of saline. G(D3) group was given 12.5 mu g of G(D3), and sialic acid group 2.5 mu g of sialic acid. The relative growth rates of control group, G(M3) 1 mu g group, G(M3) 10 mu g group on day 22 were 139+/-74, 56+/-39, 22+/-14, respectively, and statistically significant among these three groups (Mann-Whitney's U test p<0.01). There were no significant difference between control and G(D3) or sialic acid group. All of the 15 control mice had muscle invasion, however, of the 19 G(M3) 10 mu g administered mice, only 4 had muscle invasion. The incidence of muscle invasion between these 2 groups was statistically significant in chi(2) test (p<0.001). Locally administered G(M3) inhibited both invasion and growth of MBT-2 tumor. This mechanism could be explained by an important role of G(M3) in cell adhesion mediated by integrin and fibronectin interaction. These results may be applied to antiadhesion therapy of human invasive bladder tumor.

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