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Aim: To study the effect of Ferroplat (FrP) on the indexes of pro/antioxidant balance and energy metabolism in breast cancer cells of different malignancy degree and different sensitivity to drug therapy. Materials and Methods: The study was carried out on breast cancer cells of low (T47D, MCF-7) and high malignancy degree (MCF-7/DDP (cisplatin-resistant), MDA-MB-231, MDA-MB-468) using cell culture techniques, immunocytochemical, biochemical, biophysical methods, flow cytometry and polarography. Results: We established that the addition of FrP to the culture medium reduces the activity of glucose-6-phosphate dehydrogenase (G6PDH), superoxide dismutase (SOD) and the level of non-protein thiols by 32–41% (p < 0.05). At the same time, there was an increase of the total level of ROS and the rate of NO generation by inducible NO synthase by 1.7–2.5 times (p < 0.05). This testifies that FrP disturbs the antioxidant balance in cells, resulting in their death. Also, the use of FrP led to a decrease in the rate of oxygen absorption in MCF-7 and T47D cells by 26% and 25%, respectively (p < 0.05). In cells of high malignancy degree this index decreased by 38–40% under the influence of FrP. Incubation of MCF-7 and T47D cells with the indicated agent also reduced the content of phospholipid cardiolipin by 15–16% (p < 0.05), and in MDA-MB-231, MCF-7/DDP, MDA-MB-468 cells — by 29%, 30% and 32%, respectively. In addition, the effect of FrP caused a decrease in the levels of Mg2+ and lactate in MCF-7 and T47D cells by 21–29% and 14–24%, respectively, whereas in MDA-MB-231, MDA-MB-468, MCF-7/DDP cells — by 34–38% and 32–35%, respectively. In this case, the agent raised the level of glucose in the cells of low malignancy degree by 20–23% (p < 0.05), and in the cells of high malignancy degree and with the phenotype of drug resistance — by 31–36%. However, the nanocomposite did not affect the activity of lactate dehydrogenase in all studied breast cancer cells. Conclusion: The study has shown that FrP has an effect on the pro/antioxidant balance and energy metabolism of cancer cells. In addition, the denoted effect of FrP was more pronounced in the breast cancer cells with a high malignancy degree and the phenotype of drug resistance.

The transmembrane potential and genome stability of tumor cells under nanoferromagnetic action with different sizes of nanoparticles were studied in vivo. An evaluation of the genotoxic influence of nanoeferromagnetics on tumor cells and changes in their mitochondrial potential was carried out with the application of a micronuclei test and mitochondrial fluorescent probe JC 1. Nanoferromagnetics with nano particle diameters of 40 and 100 nm at a concentration of 3 mg/kg were not found to deminish the trasmem brane mitochondrial potential and the genome of tumor cells and increase the micronucleus frequency of tumor cells to only a small extent. Iron nanoparticles at a concentration of 6 mg/kg were noted to demon strate an antidromonous character of the changing mitochondrial potential and micronuclei frequency depending on their size. Iron nanoparticles with a smaller diameter were found to provoke an essential rise in the transmembrane potential of tumor cell metachondria on the background of a constant number of micro nuclei, and the opposite was true for those with a greater diameter. The data obtained can serve as an impor tant criterion for further studies in experimental oncology to create an optimal system for delivering antican cer preparations to tissue targets.