INVOLVEMENT OF RAS IN THE EXPRESSION OF GLYCOLIPID SULFOTRANSFERASE IN HUMAN RENAL-CANCER CELLS

Glycolipid sulfotransferase activity in a human renal cell carcinoma c ell line, SMKT-R3, is enhanced by epidermal growth factor (EGF); tyros ine kinase inhibitors suppress this enhancement, To investigate the in volvement of pas in the signal transduction pathway from the EGF recep tor to the expression of glycolipid sulfotransferase, we introduced v- H-ras into SMKT-R3 cells, In a quiescent state, the percent GTP bound to Ras in v-H-ras-expressing cells increased about 2.5-fold compared w ith control cells, suggesting that v-Ras introduced into the renal can cer cells is in an active form without EGF stimulation, Glycolipid sul fotransferase activity in v-H-ras-expressing cells was higher than in control cells, The sulfotransferase activity was affected neither by E GF nor by genistein, a tyrosine kinase inhibitor, in v-H-ras-expressin g cells, whereas it was enhanced by EGF and reduced by genistein in co ntrol cells, Our observations suggest that Ras mediates the regulation pathway of glycolipid sulfotransferase activity in SMKT-R3 cells. (C) 1997 Wiley-Liss, Inc.