Nitric oxide impairs the 17beta-estradiol-induced apoptosis in human colon adenocarcinoma cells.
Nitric oxide (NO) and 17beta-estradiol (E2) are both important in gastrointestinal health and disease. NO contributes to gastrointestinal motility as well as to inflammation and carcinogenic processes. By contrast, E2 reduces the incidence of colon adenoma and carcinoma by about 30%. We report the genomic and non-genomic E2-estrogen receptor (ER) beta-induced effects in human colon adenocarcinoma. The effect of NO on ERbeta activities was also assessed. The E2-ERbeta-dependent gene transcription was inhibited by exogenous NO, whereas some non-genomic E2-dependent effects (e.g. p38/MAP kinase), important for the activation of the apoptotic cascade, were unaffected by NO. However, NO impaired the E2-induced pro-apoptotic cascade in human colon adenocarcinoma cells by inhibiting caspase-3. The effects of NO may reflect chemical modification(s) of Cys residues present in the DNA recognition domain of ERbeta as well as in the caspase-3 active site. On the whole, high NO concentrations suppressed the E2 protective effects in the gastrointestinal tract, suggesting that the caspase-dependent apoptotic cascade may become critical under conditions of high redox stress such as occur under specific activation of the immune system by chronic infections or pathogen challenge.
Marino
M
M
Department of Biology, University Roma Tre, Viale G Marconi 446, I-00146 Rome, Italy. m.marino@uniroma3.it
Galluzzo
P
P
Leone
S
S
Acconcia
F
F
Ascenzi
P
P
D000230:Adenocarcinoma / Q000235:genetics / Q000378:metabolism*; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism*; D003545:Cysteine / Q000187:drug effects / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D004958:Estradiol / Q000494:pharmacology; D047629:Estrogen Receptor beta / Q000819:agonists / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006801:Humans; D009569:Nitric Oxide / Q000633:toxicity*; D014158:Transcription, Genetic / Q000187:drug effects; D014407:Tumor Cells, Cultured
D061945:Caspase Inhibitors; D047629:Estrogen Receptor beta; D009569:Nitric Oxide; D004958:Estradiol; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; D003545:Cysteine