Boron-containing conjugates of cholesterol were synthesized by the copper( i )-catalyzed 1,3-dipolar [3+2] cycloaddition reactions of cobalt and iron bis(dicarbollide) azide derivatives with alkynyl cholesterol. The antiproliferative activity (IC 50 ) of the conjugates was evaluated against a series of human cell lines by the MTT assay. All conjugates were shown to be nontoxic (IC 50 >200 µmol L −1 ) and to be applicable for the preparation of boron-containing liposomes as potential drugs for boron-neutron capture therapy (BNCT) of cancer.

A series of novel imidazole-containing ligands and their organotin complexes were synthesized and characterized by NMR, IR, MALDI and elemental analysis. Redox behavior was studied by cyclic voltammetry (CV). Antioxidant properties were estimated in model reactions of single-electron reduction (CUPRAC-test), scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and O2−. radical anion, enzymatic oxidation of linoleic acid by lipoxygenase and Fe3+-induced lipid peroxidation of rat liver homogenates. It was found that ligands and complexes both possess radical scavenging activity of prolonged action type. Compounds exhibited notable antioxidant activity in lipid peroxidation. Cytotoxicity was estimated in standard MTT-test on multiple cell lines. Compounds demonstrated high toxicity on colon carcinoma and breast cancer cells and based on obtained data, lead compound was proposed. Additional assays were carried out for the lead compound, including regular MTT-test on cancer cells possessing various resistant mechanisms and modified MTT-test on tumor tissue samples, obtained from patients as well as apoptosis and cell cycle studies. All organotin complexes were also studied for their influence on tubulin polymerization. It was demonstrated that obtained compounds demonstrate unorthodox activity, promoting microtubules assembly rate instead of inhibiting it. Significant influence of compound 5 on G2/M phase of cell cycle is in accordance with influence on tubulin polymerization and lets us to mark synthesized compounds as mitotic poisons. The results open up the scopes for the search of novel antitumor agents for treatment of advanced forms of cancer.

The search for new metal-containing antitumor agents is still carried out at present. Although platinum compounds are used in clinical practice, they show drawbacks such as high general toxicity and primary or acquired resistance. Ruthenium compounds showed the best potential among non-platinum antitumor agents, two of which—NAMI-A and KP1019 (КР1339)—are under clinical trials. In this work, we present the synthesis of full analogs of leader compound NAMI-A containing fragments of biologically active organic molecules, namely Lonidamine and Bexarotene. Electrochemical behavior of Ru(III) complexes has been studied and ease of reduction has been shown, which indicates the promise of their use as antitumor agents whose mechanism of action seems to be based on activation by metal atom reduction. The cytotoxicity of obtained complexes has been studied in vitro and IC50 values have been determined. Two compounds have been selected for further study.