GLYCOSAMINOGLYCANS ENHANCE HUMAN LEUKEMIC-CELL GROWTH IN-VITRO

We have previously shown that heparin and heparan sulfate stimulate th e growth of human erythroleukemia cells in vitro in the presence of se rum or plasma. To determine whether heparin and other glycosaminoglyca ns (GAGs) are involved in the growth of leukemia cells, effects of GAG s on the growth of three leukemia cell lines expressing different phen otypes, the HEL, HL60 and U937 cell lines were studied using both plas ma clot and serum-free agar systems. The cells were cultured with diff erent doses of six GAGs: hyaluronic acid, chondroitin sulfate, dermata n sulfate, keratan sulfate, heparin and heparan sulfate. It was found that, in serum-free agar system, no GAG was able to stimulate (HEL) ce ll growth. In contrast, when serum-containing culture systems were use d, all six GAGs promoted colony formation of HL60 and U937 cells. In a ddition, all GAGs, except keratan sulfate, stimulated the growth of HE L cells. The findings suggest that the GAGs may play an indirect role in enhancing leukemia cell proliferation by different mechanisms.