Pentosan inhibits angiogenesis in vitro and suppresses prostate tumor growth in vivo.

Pentosan polysulfate (PPS) is a highly negatively charged polysaccharide which has activity against multiple tumor types in the preclinical setting. We demonstrate here that Pentosan inhibits the growth of the anaplastic Dunning R3327 rat prostate adenocarcinoma MAT-LyLu when treatment was started when the tumor was not palpable but has little effect against established tumors. This inhibition may be mediated by the effect of Pentosan on endothelial cells. Pentosan, in combination with hydrocortisone, inhibits endothelial cell motility and tubule formation in vitro and inhibits capillary formation in the chicken chorioallantoic membrane (CAM) assay. These data suggest that Pentosan may be a potent inhibitor of tumor-associated angiogenesis and may be an effective agent for the prevention and/or suppression of prostate cancer growth.