12-O-tetradecanoylphorbol-13-acetate may both potentiate and decrease the generation of apoptosis by the antileukemic agent arsenic trioxide in human promonocytic cells. Regulation by extracellular signal-regulated protein kinases and glutathione.
Arsenic trioxide (As(2)O(3)) caused apoptosis in U-937 human promonocytic cells. This effect was potentiated by the simultaneous addition of the glutathione (GSH) synthesis inhibitor DL-buthionine-(R,S)-sulfoximine or the protein kinase C activators 12-O-tetradecanoylphorbol-13-acetate (TPA) and bryostatin 1. In addition TPA decreased the intracellular GSH content, caused ERK activation, and potentiated the As(2)O(3)-provoked activation of p38 and JNK. The addition of N-acetyl-L-cysteine, the PKC inhibitor GF109203X, and the MEK/ERK inhibitors PD98059 and U0126 attenuated both apoptosis induction and GSH decrease, whereas the p38 inhibitor SB203580 and the JNK inhibitor SP600125 were ineffective. TPA also potentiated ERK activation and GSH depletion when added simultaneously to cadmium chloride (CdCl(2)) and doxorubicin. However, TPA only enhanced apoptosis in the case of CdCl(2), which is a GSH-sensitive agent, whereas it reduced the toxicity of doxorubicin and other DNA-specific drugs. Finally, preincubation for 14-24 h with TPA did not potentiate but, instead, attenuated the As(2)O(3)- and CdCl(2)-provoked apoptosis. The same result was obtained by preincubation with bryostatin 1 and other differentiation inducers. It is concluded that TPA increases the apoptotic action of As(2)O(3), an effect mediated by ERK activation and GSH depletion. However, the increase in apoptosis is only effective in non-differentiated cells.
Fernández
Carlos
C
Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain.
Ramos
Adrián M
AM
Sancho
Patricia
P
Amrán
Donna
D
de Blas
Elena
E
Aller
Patricio
P
D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis; D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000378:metabolism / Q000494:pharmacology*; D019328:Buthionine Sulfoximine / Q000494:pharmacology; D019256:Cadmium Chloride / Q000494:pharmacology; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004317:Doxorubicin / Q000494:pharmacology; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009000:Monocytes / Q000378:metabolism*; D010087:Oxides / Q000378:metabolism / Q000494:pharmacology*; D011493:Protein Kinase C / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000031:analogs & derivatives* / Q000494:pharmacology*; D013997:Time Factors; D020298:U937 Cells; D048051:p38 Mitogen-Activated Protein Kinases
D000903:Antibiotics, Antineoplastic; D000964:Antimetabolites, Antineoplastic; D000970:Antineoplastic Agents; D001152:Arsenicals; D004791:Enzyme Inhibitors; D010087:Oxides; D019328:Buthionine Sulfoximine; C020922:4-O-methyl-12-O-tetradecanoylphorbol 13-acetate; D004317:Doxorubicin; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; D005978:Glutathione; D019256:Cadmium Chloride; D013755:Tetradecanoylphorbol Acetate; D000077237:Arsenic Trioxide