The growth of supportive tissue during the progression of solid
tumors is an absolute requirement for the nourishment of the
tumor. The blockade of this proliferative response of normal tissues to the growing
tumor should hence inhibit
tumor progression. We have shown earlier, that the
heparinoid pentosan polysulfate (PPS) can block
tumor growth and neoangiogenesis induced by Kaposi's FGF as well as by other
heparin-binding
growth factors (HBGFs). We now report on the effects of a bacterial
polysaccharide,
tecogalan, on
tumor xenografts of human
breast cancer cells.
Tecogalan inhibited FGF-dependent SW-13 cells in vitro very similarly to PPS.
Growth factor-independent MDA-MB 231 cells were used in animal studies to assess the in vivo potential of
tecogalan. Subcutaneous growth of
tumors was inhibited by once weekly i.v. administration of
tecogalan. PPS single weekly administration showed a similar effect. No gross side effects were observed. Based on our previous studies with these models, we conclude, that
tecogalan acts by blocking HBGFs released from
tumor cells. Interestingly, single weekly dosing of either PPS or
tecogalan appears to be strikingly more efficacious than spreading the dose over several administrations. These findings with a novel compound,
tecogalan, and a novel treatment regimen, PPS, suggests a different approach to planning of
therapies with these types of drugs.