Ozone Induced Cell Death in HeLa cell Culture Mediated through Stimulation of TNF- Alpha

Abstract

Ozone has been in used as a therapeutic agent for the treatment of infective and inflammatory diseases, including cancer. The relationship of ozone with cancer and mechanism underlying the therapeutic effect of ozone on cancer remain unclear. This is first attempt to study the effect of ozone on cancer cells and how ozone induced cell death is mediated by activation of tumor necrosis factor (TNF)-? by using in vitro cell culture method. In the present study, HeLa cell cultures were subjected to ozone treatment at different dosages (10, 20, 30 & 40 ?g/ml). HeLa cells exhibited an increasing cell death with increase in ozone doses studied. A substantial enhancement of cell death was observed after 18 hours of ozone treatment onwards. Treatment with 30 and 40 ?g/ml of ozone showed an elevated sensitivity to growth inhibition compared to the treatments 10 and 20?g/ml. Additionally cell detachment and cell floating were also faster and higher in ozone treatment with 30 and 40?g/ml. Tumor necrosis factor alpha (TNF-?), is a multifunctional cytokine playing a key role in apoptosis and cell survival as well as in inflammation and immunity. Hence we also studied the release of TNF-? in response to various dosages of ozone-treatments by using ELISA technique. We found that TNF-?, secretion was found to be enhanced with increase in cell death and at dose 40?g/ml ozone treatment, cell death was highest and TNF-? secretion was also highest. Our study suggests that ozone induced cell death in HeLa cell lines is mediated through the activation of TNF-? pathway and the role of ozone in inducing apoptosis cannot be ruled out.