REVERSING EFFECT OF ,5'6'-DIMETHYLENEDIOXYBIPHYNYL1-2,2'-DICARBOXYLATE (DDB) ON THE PHENOTYPES OF HUMAN HEPATOCARCINOMA CELLS LINE

When human Bel-7402 hepatocarcinoma cell line grew in a medium contain ing 10(-4) M dimethyl-4,4'-dimethoxy-5,6,5',6'- dimethylenedioxybiphyn yl-2,2'-dicarboxyl (DDB), the secretion of alpha-fetoprotein (AFP) was significantly lower than the control cells, whereas the albumin (ALB) secretion was markedly higher. The activity of gamma-glutamultranspep eidase (gamma-GT) in DDB-treated cells markedly decreased in compariso n with the control cells. On the contrary, the activity of tyrosine-al pha-ketoglutarate transaminase (TAT) was higher in DDB-treated cells t han in control cells. DDB (10(-4) M) could significantly increase the content of cAMP in Bel-7402 cells, and also enhance the expression of anti-oncogene p53. The results suggest that DDB has reversing effects on the phenotypes of the human Bel-7402 hepatocarcinoma cell line.