OA257] Influence of nonionizing millimeter electromagnetic radiation on tumor and healthy DNA

Abstract

Purpose The present study was undertaken to investigate whether millimeter range electromagnetic nonionizing radiation (NIR) of selective frequencies can suppress tumor cells growth in vivowithout cytostatic agents. Methods The course of influence of NIR started 3 days before transplantation in order to raise activity of the animals immune system. On the fourth day animals were injected by sarcoma-37 and daily exposure was continued during 15 days. For study of the effect of irradiation on the secondary structure of DNA, in the experiments DNA isolated from the liver of healthy mice (hDNA) as well as from the tumor sarcoma 37 (tDNA) was used. Results After 15 sessions of exposure without cytostatics, at animals of the irradiated 0,5 h was observed an inhibition of tumor growth by 33.5% compared with a control group and a sharp suppression of the level of DNA methylation in 2.1 times. The tDNA has the high level of methylation (4.7 mol%), which after 0.5 h daily exposure becomes (2.2 mol%) close to the corresponding value for hDNA (1.9 mol%). Differential melting curves (DMC) of tDNA are shifted relatively DMC of the hDNA to lower temperatures, and in the DMC of tDNA the additional peaks are appeared. The obtained results are correlated with the spectrophotometric data. Under the influence of millimeter NIR the values of temperature and interval of melting of tDNA are changed and approach to the corresponding values of hDNA. Conclusions Hypermethylation of tumor DNA may cause a selective sensitivity of malignant cells toward the influence of the NIR which allows an expressed antitumor effect. It is possible, that 30 min daily exposure leads to the activation of specific molecular mechanisms of cells, resulting in a decrease of undesirable structural changes in the tumor DNA and inhibition of tumor growth. Presented preliminary results have demonstrated the promising application of millimeter NIR for clinical oncology in the treatment of malignancies without damaging other tissues and antitumoral drugs and without harmful ionizing radiotheraphy.