Penicillamine as a potent protector against injurious effects of cigarette smoke in aerodigestive tract cancer.

摘要

BACKGROUND: Cigarette smoke (CS) is the major risk factor for aerodigestive tract cancers such as lung and oral cancers. METHODS: In in vitro models of lung and oral cancers, we found D-penicillamine (PenA) to be a most potent protector against CS, both in the absence and presence of saliva (a highly pro-oxidative condition). RESULTS: The survival rate of lung cancer cells and oral cancer cells was reduced by CS in the absence of saliva by 39-45% (p < 0.01) and by 55-60% (p < 0.01) in the presence of saliva. The addition of 5 mM PenA to cell medium prior to CS exposure limited cell loss to 22-25% only (p < 0.01). Similarly, the iron chelator desferal protected the cells only in the presence of saliva. PenA also protected against a CS-induced increase in carbonyls (oxidized proteins) and decrease in p53 levels (in the presence of saliva) and mitochondrial membrane potential (a hallmark of CS-induced apoptotic cell death). Malfunctioning p53 often characterizes carcinogenesis of CS-induced cancers. CONCLUSIONS: Redox-active iron and copper in pleural fluid and saliva, upon encounter with CS, may be responsible for this carcinogenesis, mediated via alteration of p53 function. Chelation of redox-active metals may be an efficient tool for prevention of CS-induced lung and oral cancers. The superiority of PenA results from its copper-chelating action as well as its antialdehyde and anti-inflammatory capabilities.