Cytoprotective Effects and Intranuclear Localization of Sulfur-Containing Derivative of Buckminsterfullerene.

Background: There is a growing interest in exploring the biological characteristics of nanoparticles and exploring their potential applications. However, there is still a lack of research into the potential genotoxicity of fullerene derivatives and their impact on gene expression in human cells. In this study, we investigated the effects of a water-soluble fullerene derivative, C60[C6H4SCH2COOK]5H (F1), on human embryonic lung fibroblasts (HELF).

Methods: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test was used to study the cytotoxicity of F1; reactive oxygen species (ROS) level was determined with 2,7-DCFH-DA; gene expression level was evaluated by reverse transcription polymerase chain reaction (RT-PCR); protein expression level was determined by flow cytofluorometry; fluorescence microscopy was used for visualization; Mann-Whitney statistical U-test was used for data processing. The differences were considered significant at p < 0.01.

Results: F1 at a concentration of 0.3 mg/mL causes a short-term (up to 1 hour) increase in the number of double-strand breaks and oxidative DNA damage in HELF. Within 1 to 24 hours, F1 penetrates through the cell and nuclear membrane of HELF and localizes in the nucleus. In this case, the response of cells to DNA damage is activated: the functional activity of DNA repair genes, antioxidant and anti-apoptotic genes is increased within 24 hours. Due to the processes of activation of cell division and inhibition of apoptosis, an increase in the population of HELF cells in the presence of the fullerene derivative F1 is observed. F1 has a stabilizing effect on cell nuclei under the action of 1 Gy radiation.

Conclusions: An increase in antioxidant protection, activation of repair genes, anti-apoptotic genes, progression of the cell cycle, and a decrease in the level of oxidative damage, and DNA breaks in cells indicates the cytoprotective properties of F1.