Synthesis and evaluation of analogues of 10H-indolo[3,2-b]quinoline as G-quadruplex stabilising ligands and potential inhibitors of the enzyme telomerase.

We report here the synthesis and evaluation for telomerase-inhibitory and quadruplex DNA binding properties of several rationally-designed quindoline analogues, substituted at the 2- and 7- positions. The ability of these compounds to interact with and stabilise an intramolecular G-quadruplex DNA against increases in temperature was evaluated by a fluorescence-based (FRET) melting assay. The resulting T(m) values were found to correlate with their potency for telomerase inhibition, as measured in an in vitro telomerase TRAP assay. The interactions of a number of compounds with a quadruplex DNA molecular structure were simulated by molecular modelling methods. It is concluded that this class of compound represents a new chemical type suitable for further development as telomerase inhibitors.