Glycosaminoglycans in 3'-methyl-4-dimethylaminoazobenzene-induced rat hepatic cancer

Abstract

The changes in glycosaminoglycans in livers of rats with 3'-methyl-4-dimethylaminoazobenzene-induced hepatic cancer were examined and compared with those in fetal liver. The incorporation of 35S into sulfated glycosaminoglycans in hepatic cancer tissue was also studied after i.p. injection of Na(2)35SO4. The major component of glycosaminoglycans in healthy adult rat liver was heparan sulfate (61.7%), with hyaluronic acid (21.1%), dermatan sulfate (13.1%), and chondroitin sulfate (4.0%) as minor components. The quantities of all of the examined glycosaminoglycans were higher in tumors than in normal liver, but chondroitin sulfate and hyaluronic acid were more prevalent in the tumors (about 51 and 7 times higher, respectively). As a result, the share of heparan sulfate was decreased (37.1%) in the tumors. The high content of chondroitin sulfate (about 30 times) and the decreased share of heparan sulfate (29.0%) were also observed in fetal liver. The incorporation of 35S into individual glycosaminoglycans varied markedly. Approximately 90% of the label in glycosaminoglycans of healthy liver was found in a heparan sulfate fraction 4 hr after injection. In hepatic cancer tissue, however, 35S incorporation into both chondroitin sulfate and dermatan sulfate fractions was increased about 6.5- and 5.6-fold, respectively, of those in healthy liver.