Effects of smoking and tumor process on the contents of key proteins of apoptosis and activity of antioxidant enzymes in blood

The effects of smoking on the contents of the apoptosis markers Bcl-2 and p53 proteins in blood plasma; the activity of the antioxidant (AO) enzymes Cu,Zn superoxide dismutase (SOD), glutathione peroxidase (GP), glutathione reductase (GR), glutathione S-transferase (GST), and catalase; and the content of malondialdehyde (MDA) in erythrocytes from healthy donors and cancer patients were studied. Two groups of donors were revealed among healthy smokers: one with high SOD and GP activities and high Bcl-2 protein levels and the other with lower Bcl-2 levels compared with those found in nonsmokers. In the group of cancer patients (both smokers and nonsmokers), significantly increased p53 protein levels and increased activity of GST were found. A negative correlation between MDA and GST in the group of smoking healthy donors and a positive correlation between MDA and p53 in cancer patients were found. The results suggest a relationship between the components of enzymatic defence and lipid peroxidation and the content of apoptosis regulator proteins in healthy smokers and cancer patients.