Structural revision of sulfated polysaccharide B-1 isolated from a marine Pseudomonas species and its cytotoxic activity against human cancer cell lines

The structure of a sulfated polysaccharide (B-1) isolated and purified from the culture filtrate of marine Pseudomonas sp. WAK-1 was revised to have a repeating unit as follows: -2)-beta-D-Ga1p(4SO(4)) (1-4) [beta-D-Glcp(1-6)] -beta-D-Galp(3SO(4)) (1-B-1 was evaluated for anticancer activity using a human cancer cell line panel coupled with a drug sensitivity database. The average B-1 concentration required for 50% growth inhibition against the panel of 39 cell lines was 63.2 mug/ml. Among the cancer cell lines tested, high sensitivities to B-1 were observed in central nervous system cancer and lung cancer cell lines. The COMPARE analysis revealed that the differential growth inhibition pattern of B-1 had no significant correlation with those of more than 200 standard compounds, most of which were anticancer drugs and different types of inhibitors. This lack of similarities in the cytotoxic patterns appears to reflect previously unrecognized biological properties of B-1. It was revealed that B-1 induced apoptosis in U937 cells, as shown by cell morphology and internucleosomal DNA fragmentation.