EPIDERMAL GROWTH-FACTOR ELEVATES THE ACTIVITY LEVELS OF GLYCOLIPID SULFOTRANSFERASES IN RENAL-CELL-CARCINOMA CELLS

Accumulation of sulfoglycolipids associated with markedly elevated lev els of glycolipid-sulfotransferase activity was previously demonstrate d in human renal-cell-carcinoma cells. To elucidate the regulatory mec hanisms of sulfoglycolipid metabolism in renal-cell carcinoma, effects of various growth factors on the sulfotransferase-activity levels wer e investigated using a human renal-cell-carcinoma cell line, SMKT-R3. Exogenous epidermal growth factor (EGF) significantly increased the ac tivity levels of the sulfotransferases in a dose-dependent manner, but did not change that of arylsulfatase A, which hydrolyzes sulfoglycoli pids. Furthermore, metabolic labeling with S-35-sulfate revealed that the addition of EGF to the culture medium of the cells resulted in an increment of sulfoglycolipid synthesis. The expression of the EGF rece ptor on SMKT-R3 cells was demonstrated by affinity cross-linking with I-125-EGF. These observations suggest that EGF can regulate sulfotrans ferase-activity levels in renal-cell-carcinoma cells, and function as one of the regulatory factors of sulfoglycolipid synthesis in these ca rcinoma cells. (C) 1993 Wiley-Liss, Inc.