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

Accumulation of sulfoglycolipids associated with markedly elevated activity levels of glycolipid sulfotransferases has previously been demonstrated in the human renal cell carcinoma cell Line, SMKT-R3. To elucidate the regulatory mechanisms of sulfoglycolipid synthesis in SMKT-R3 cells, the effects of various growth factors on the metabolic enzymes of sulfoglycolipids were investigated. Hepatocyte growth factor (HGF) significantly increased the activity levels of the sulfotransferases in a dose-dependent manner, but did not change that of arylsulfatase A, which hydrolyzes sulfoglycolipids. Scatchard analysis of I-125-HGP binding to SMKT-R3 cells indicated that the cells expressed high-affinity receptors for HGF with a K-d of 36 pM and 750 sites/cell. Furthermore, metabolic labeling with [S-35]sulfate revealed that the addition of HGF to the culture medium of the cells resulted in an increment of sulfoglycolipid synthesis. Therefore, these observations suggest that HGF can function as a regulatory factor in sulfoglycolipid synthesis through the modulation of the sulfotransferase activity levels in renal cell carcinoma cells. In addition, HGF stimulated the proliferation and motility of SMKT-R3 cells, suggesting that HGF has multiple biological activities in renal cell carcinoma cells.