Nanobiotechnology for health-care

Formation of reactive oxygen species as one of the triggers of antitumor action of nanocomplexes
Goltsev A.M., Bondarovych M.O., Babenko N.M., Gaevska Yu.O.,    Dubrava T.G., Ostankov M.V.
Cryopathophysiology and Immunology Department, Institute for Problems of Cryobiology & Cryomedicine of the National Academy of Sciences of Ukraine. Pereyaslavska Str, 23, Kharkiv-61016, Ukraine.
E-mail:cryopato@gmail.com.

Experimental study of the antitumor effects of nanocomplexes (NCs), consisting of nanoparticles of GdYVO4:Eu3+ and cholesterol, indicates the feasibility of their use in oncology practice. The mechanism of implementation of the antitumor effect of NCs may be associated with the formation of reactive oxygen species (ROS) with subsequent death of tumor cells, so the aim of the research was to study the pro-oxidant and antitumor properties of these NCs. The experiments were performed in Ehrlich ascites carcinoma (EAC) cells induced in BALB / c mice by intraperitoneal administration of 5x106 cells / mouse in 0.3 ml of saline. On day 7 of culturing in the peritoneal cavity of mice, EAC cells were removed with a syringe and in vitro treated with NCs at the rate of 100 μl of NCs solution per 900 μl of EAC cells 1x107 cells / ml at room temperature for 3 hours. The control was bone marrow (BM) cells, treated with NCs in a similar manner. ROS production was quantified by flow cytometry using the Fluorometric Intracellular ROS Kit (Sigma-Aldrich, USA), the level of metabolic activity of cells was found with the Cell growth determination kit MTT based (Sigma, USA), apoptotic and necrotic cells were numbered by FITC Annexin V Apoptosis Detection Kit I (BD, USA). The EAC cells before NCs treatment were found to have a basal level of ROS production at 12.16 ± 0.93%, which was twice higher than in BM cells. Treatment with NCs increased the number of ROS-positive cells in BM by 1.8 times and in EAC by more than 3 times compared to the corresponding basal levels of this index, which was a prerequisite for a deeper disorder of their functional state. Indeed, under the influence of NCs, the inhibition rate of metabolic activity of EAC cells by MTT test was almost 2 times greater than that of BM cells, that is a reflection of inhibition of NADP-H-dependent oxidoreductase enzymes of mitochondria. This led to a significant decrease (by 25%) in the number of living (An– / PI–) EAC cells, and their predominant death by necrosis. The results obtained can be taken into account when creating new strategies for cancer therapy.