tosylphenylalanyl-chloromethyl-ketone and 1-oleoyl-2-acetylglycerol

We have measured the levels of thioredoxin, thioredoxin reductase and glutaredoxin enzyme activity in mouse skin following topical application of the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA), a protein kinase C (PKC) activator and tumor promoter. The specific activity of thioredoxin and thioredoxin reductase in extracts from normal epidermis increased by 40 and 50%, respectively, after single or multiple application of TPA. Multiple applications (twice per week for 2 weeks) of TPA increased glutaredoxin activity by >300%. Induction of the proteins lasted several days. Other PKC activators, like 12-O-retinoylphorbol 13-acetate, mezerein, 1-oleoyl-2-acetylglycerol and the calcium ionophore A23187, also induced all the enzyme activities. Phorbol and 4-O-methyl-12-O-tetradecanoylphorbol-13-acetate, weak activators of PKC, selectively induced the thioredoxin system only and did not influence glutaredoxin activity. Multiple applications of TPA to tumor initiated (7,12-dimethyl[a]benzanthracene-treated) skin resulted in elevated levels of both the thioredoxin and glutaredoxin systems when examined 6 days after the last phorbol ester treatment. Induction of thioredoxin, thioredoxin reductase and glutaredoxin activities by TPA and calcium ionophores may play a general role in the epigenetic mechanism of tumor promotion via thiol redox control mechanisms.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Calcimycin; Calcium; Carcinogens; Cocarcinogenesis; Diglycerides; Diterpenes; Enzyme Activation; Enzyme Induction; Epidermis; Female; Fluocinolone Acetonide; Gene Expression Regulation; Glutaredoxins; Glutathione; Ionophores; Mice; Oxidation-Reduction; Oxidoreductases; Phorbol Esters; Protein Kinase C; Proteins; Skin Neoplasms; Terpenes; Tetradecanoylphorbol Acetate; Thioredoxin-Disulfide Reductase; Thioredoxins; Tosylphenylalanyl Chloromethyl Ketone; Tretinoin

In the presence of the protease inhibitors phenylmethyl-sulfonyl fluoride and N-tosyl-L-phenylalanine chloromethyl ketone, prostacyclin (PGI2) production by rat liver cells treated with epidermal growth factor, platelet-activating factor, 12-0-tetradecanoylphorbol-13-acetate (TPA), and TPA-type tumor promoters (teleocidin and aplysiatoxin) or 1-oleoyl-2-acetylglycerol is amplified. The PGI2 production stimulated by thapsigargin or exogenous arachidonic acid is not amplified. N-Tosyl-L-phenylalanine chloromethyl ketone also amplifies TPA's release of radioactivity from cells isotopically labeled with [3H]arachidonic acid. Indomethacin inhibits the amplification of PGI2 production but no the release of radioactivity. The presence of the protease inhibitors is not required for the amplification of PGI2 production. Prior incubation of the cells with these inhibitors, followed by their removal, still results in amplified PGI2 production by cells subsequently treated with TPA, 1-oleoyl-2-acetylglycerol, or platelet-activating factor but not that stimulated by exogenous arachidonic acid. While phenylmethyl-sulfonyl fluoride's amplification of PGI2 production by cells treated with TPA was blocked by prior incubation with TPA for 20 h, a similar block of amplification in EGF-treated cells was not observed.

Topics: Animals; Arachidonic Acid; Carcinogens; Cell Line; Diglycerides; Epoprostenol; Indomethacin; Liver; Lyngbya Toxins; Phenylmethylsulfonyl Fluoride; Protease Inhibitors; Rats; Serine Proteinase Inhibitors; Tetradecanoylphorbol Acetate; Tosylphenylalanyl Chloromethyl Ketone