A protein disulfide-thiol interchange activity of HeLa plasma membranes inhibited by the antitumor sulfonylurea N-(4-methylphenylsulfonyl)-N'-(4-chlorophenyl) urea (LY181984)
Plasma membrane vesicles isolated from HeLa cells grown in suspension culture contain a protein disulfide-thiol interchange (protein disulfide-like) activity. The activity was estimated from the restoration of activity to inactive (scrambled) pancreatic RNAase. RNAase activity was measured either by hydrolysis of cCMP or by a decrease in acid precipitable yeast RNA. The ability of plasma membrane vesicles to restore activity to inactive (scrambled) pancreatic ribonuclease was inhibited by the antitumor sulfonylurea N-(4-methylphenylsulfonyl)-N'-(4-chlorophenyl)urea (LY181984). The activity correlated with that of a cyanide-resistant NADH oxidase also associated with the plasma membrane vesicles that exhibited a similar pattern of drug response. The activity was stimulated by reduced glutathione and inhibited by oxidized glutathione but did not depend on either for activity. The antitumor sulfonylurea-inhibited activity was greatest in the presence of reduced glutathione and least in the presence of oxidized glutathione. The antitumor sulfonylurea-inhibited activity was unaffected by a monoclonal antibody to protein disulfide isomerase. Also the antitumor sulfonylurea-inhibited activity was unaffected by peptide antisera to the consensus active site sequence of protein disulfide isomerase. Thus the antitumor sulfonylurea-inhibited activity appeared to reside with a novel cell surface protein capable of oxidation of both NADH and protein thiols and of carrying out a protein disulfide isomerase-like protein disulfide-thiol interchange activity in the absence of NADH or other external reductants.
Morré
D J
DJ
Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA.
Jacobs
E
E
Sweeting
M
M
de Cabo
R
R
Morré
D M
DM
D000970:Antineoplastic Agents / Q000494:pharmacology*; D002462:Cell Membrane / Q000201:enzymology*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006367:HeLa Cells; D006801:Humans; D007535:Isomerases / Q000037:antagonists & inhibitors*; D009097:Multienzyme Complexes / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D019704:Protein Disulfide-Isomerases; D013453:Sulfonylurea Compounds / Q000494:pharmacology*
D000970:Antineoplastic Agents; D004791:Enzyme Inhibitors; D009097:Multienzyme Complexes; D013453:Sulfonylurea Compounds; C062821:LY 181984; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases; D007535:Isomerases; D019704:Protein Disulfide-Isomerases