Effect of n-acetylcysteine on apoptosis of P19 cancer cells during hypoxia

Introduction. Hypoxia in tumor growth contributes to mitochondrial dysfunction and exacerbates oxidative stress in the immortalized cell. The objective of the study was to investigate the molecular mechanisms of the effects of N-acetylcysteine on redox regulation of tumor cell apoptosis under hypoxia. Material and Methods. P19 cells (mouse teratocarcinoma) cultured under hypoxia served as the material for the study. The redox status was modulated with N-acetylcysteine in the final concentration of 5 mM. The level of reactive oxygen species, concentration of calcium ions, transmembrane potential and the number of CD95-, CD120-and Annexin V-positive cells were determined by flow cytometry. The concentration of glutathione system components as well as the levels of protein SH groups and protein carbonyl derivatives were measured by spectrophotometry. Results. The use of N-acetylcysteine under hypoxic conditions was accompanied by the increased total glutathione concentration and protein SH groups levels, decreased levels of Са2+ ions, protein-bound glutathione and protein carbonyl derivatives, as well as the production of reactive oxygen species and more appropriate functioning of P19 cells mitochondria. N-acetylcysteine contributed to the development of additional resistance of P19 cells to apoptosis under hypoxia. Conclusion. The alteration in the state of the glutathione system under hypoxia influences the changes in tumor cell metabolism on the whole and promotes formation of additional mechanisms to escape apoptosis.