Symmetric and dissymmetric carbohydrate-phenyl ditriazole derivatives as DNA G-quadruplex ligands: Synthesis, biophysical studies and antiproliferative activity

Here we present a novel G4-binding family of compounds based on a central core of phenyl ditriazole (PDTZ) modified with carbohydrates and phenyl pyrrolidinyl side-chains. Their synthesis was achieved using controlled click chemistry conditions to obtain both, symmetric and dissymmetric carb-PDTZ derivatives without any intermediate protecting steps through an optimized methodology. Binding of the new carb-PDTZ to a variety of G-quadruplex motifs was examined using different biophysical techniques. The symmetric carb-PDTZ derivatives were not able to stabilize G4, but the dissymmetric ones (containing one sugar and one phenyl pyrrolidinyl side-chain) did. Interestingly, the dissymmetric carb-PDTZ derivatives showed much higher G4 vs duplex DNA selectivity than the control compound PDTZ 1, which contains two phenyl pyrrodilinyl side-chains and no carbohydrates. Their potential antitumoral activity was also investigated by in vitro cytotoxicity measurements on different cancerous cell lines. All carb-PDTZ derivatives showed higher IC₅₀ values than the control PDTZ 1, probably due to the lack of compound stability of some derivatives and to lower cellular uptake.