Evaluation of the effectiveness of the combined effect of ionizing radiation of different quality and doxorubicin on HeLa cells

Currently, experimental and medical radiology is faced with the need to solve an acute problem – the search for new promising methods of treating tumor diseases. In this regard, it seems relevant both from the point of view of practical application in medicine and from the point of view of fundamental knowledge to conduct a study to find new combinations of the action of ionizing radiation with different LET with anticancer drugs of DNA-directed action on human tumor cells. The aim of the work is to evaluate the effects of the combined action of C-12 ions and gamma radiation together with doxorubicin on the ability of Hela cells to form colonies. The cells were irradiated with C-12 ions on a U-70 synchrotron at doses of 1, 2, 4 Gy in an aqueous phantom with an average energy of 450 MeV/nucleon. The average LET of radiation at the initial site was 11 keV/µm, at a peak of 120-140 keV/µm. The irradiation was also carried out at the “GUR-120” gamma radiation facility (source of ionizing radiation Co-60, E=1.25 MeV). The dose rate is 0.9 Gy/min. Radiation doses: 1, 2, 4, 6 Gy. An antitumor antibiotic of the anthracycline series doxorubicin at a concentration of 0.004 mg/ml was selected as a chemical agent. Based on these survival curves, the coefficient of interaction was calculated. When combined with gamma radiation in the studied dose range with doxorubicin, an antagonistic effect is observed (k=0.44+/-0.07). The synergistic nature of the interaction was observed under the action of C-12 ions (k=1.40+/-0.04). The obtained results of the combined action of the agents used may have important practical and theoretical significance for understanding the mechanism of combined exposure to ionizing radiation of different quality and the chemotherapy drug doxorubicin.