Toxicity of new monophenolic synthetic activator of Keap1/Nrf2/ARE redox-sensitive signaling system in vitro and in vivo

One of the promising areas of modern pharmacology is the development of «indirect antioxidants» capable of activating redox-sensitive signaling systems, primarily the Keap1/Nrf2/ARE system. Among its chemical inductors is the hydrophilic monosubstituted monophenol (3’-tert-butyl-4’-hydroxyphenyl)sodium propylthiosulfonate (TS-13) in development. The aim of the study was to investigate TS-13 antiproliferative activity against tumor cell line BT-474 in vitro and acute oral toxicity in mice in vivo. Material and methods. The relationship between TS-13 concentration and proliferative activity of human breast ductal carcinoma cell line BT-474 was determined using the MTT test, the IC50 was calculated and compared to the previously obtained for MCF-7 line; results were correlated with the functional properties of cells based on gene expression (in silico GSEA). In vivo acute toxicity was studied in 50 female C57Bl/6J mice, who received a TS-13 solution in distilled water at various doses by intragastric gavage. LD50 obtained experimentally and predicted in silico using the GUSAR web service were compared. Results and discussion. TS-13 inhibited the proliferation of BT-474 cells in a concentration-dependent manner (exponential approximation, IC50 = 59.5 μM) and was 2.2 times more toxic than for MCF-7 cells. This may be due to functional differences between the BT-474 and MCF-7 lines, as evidenced by the GSEA results. The LD50 value established in the in vivo experiment was 936 mg/kg body weight, the obtained value satisfactorily corresponds to the predicted in silico (561 mg/kg), although in reality the compound turned out to be somewhat less toxic than could be expected based on its structure. Conclusions. A study of the acute toxicity of the new water-soluble monophenol TC-13 allows the classification of it as slightly toxic (toxicity rating level 4) according to the Hodge – Sterner scale) or as moderately hazardous (hazard class 3) according to GOST 12.1.007-76.