3-Aminobenzamide inhibits poly(ADP ribose) synthetase activity and induces phosphoenolpyruvate carboxykinase (GTP) in H4IIE hepatoma cells.
The purpose of this study was to determine whether changes in ADP-ribosylation affect expression of the gene encoding the gluconeogenic enzyme phosphoenolpyruvate carboxykinase (PEPCK) in H4IIE hepatoma cells. Treatment with 3-aminobenzamide, a specific inhibitor of poly(ADP ribose) synthetase, caused an 89% decrease of ADP-ribosylation in isolated nuclei, and resulted in a two- to threefold induction of immunoassayable PEPCK in cultured cells. In contrast, the structurally related compound p-aminobenzoic acid had no significant effect on either process. In vivo labeling of proteins with [35S]methionine, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography, showed that the induction of immunoreactive PEPCK by 3-aminobenzamide was due to a selective increase in the synthesis of the protein. The specific induction of PEPCK synthesis by 3-aminobenzamide was accounted for by a twofold increase of mRNAPEPCK which reached its maximal value 4 h after the addition of 3-aminobenzamide and returned to the basal level by 10 h. A possible role of ADP-ribosylation in cAMP or glucocorticoid induction of PEPCK was investigated in experiments in which H4IIE cells were treated with combinations of 3-aminobenzamide and either dexamethasone or a cAMP analog. In each case the effects on PEPCK induction were additive, indicating that glucocorticoids and cAMP induce PEPCK by pathways different from that used by 3-aminobenzamide.
Leverence
R R
RR
Department of Internal Medicine, VA Medical Center, Iowa City, Iowa 52242.
Beale
E G
EG
Granner
D K
DK
D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D001549:Benzamides / Q000494:pharmacology*; D006528:Carcinoma, Hepatocellular / Q000201:enzymology*; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004790:Enzyme Induction / Q000187:drug effects; D006801:Humans; D007163:Immunosorbent Techniques; D008113:Liver Neoplasms / Q000201:enzymology*; D008715:Methionine / Q000378:metabolism; D010729:Phosphoenolpyruvate Carboxykinase (GTP) / Q000096:biosynthesis* / Q000235:genetics; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D012333:RNA, Messenger / Q000096:biosynthesis; D013873:Thionucleotides / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D001549:Benzamides; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D012333:RNA, Messenger; D013873:Thionucleotides; D000246:Adenosine Diphosphate Ribose; C015929:8-((4-chlorophenyl)thio)cyclic-3',5'-AMP; D003907:Dexamethasone; C025160:3-aminobenzamide; D008715:Methionine; D000242:Cyclic AMP; D010729:Phosphoenolpyruvate Carboxykinase (GTP)