ABSTRACT
A series of 4,5-di-substituted acridones have been designed and synthesized. Several compounds show high affinity for telomeric G-quadruplex DNA in classical and competition FRET assays, together with low duplex DNA affinity, although they do not show activity in a telomerase assay or evidence of telomere shortening. They have low toxicity against a panel of cancer cell lines and a normal human fibroblast line, and produce potent senescence-based long-term growth arrest in the MCF7 and A549 cancer cell lines.
Subject(s)
Acridines/chemistry , Antineoplastic Agents/chemical synthesis , G-Quadruplexes , Acridines/chemical synthesis , Acridines/toxicity , Acridones , Antineoplastic Agents/chemistry , Antineoplastic Agents/toxicity , Cell Line, Tumor , Drug Design , Drug Screening Assays, Antitumor , Humans , Ligands , Telomerase/metabolism , Telomere/metabolism , Transition TemperatureABSTRACT
Telomerase and telomere maintenance are emerging targets for the treatment of human cancers. We report here on the targeting of the telomere-telomerase complex with a series of small molecules based on an acridine platform. A series of 3,6-bisamidoacridines with extended 9-anilino sidechains were designed and synthesised as potential telomeric G-quadruplex DNA (G4) interacting compounds. G4-stabilisation was assessed using a high-throughput FRET (fluorescence resonance energy transfer) assay and telomerase inhibition quantified by a modified TRAP (telomerase repeat amplification protocol) method. Within the series, the compounds showed significant G4-stabilising ability (Delta T(m) values of 25-36 degrees C at 1 microM concentration) and telomerase inhibition in the nanomolar region ((tel)EC(50) values of 80-318 nM). Furthermore, a direct correlation between the FRET and TRAP assays was observed, supporting the use of the rapid screening FRET assay for early assessment of potential G4-stabilising telomerase inhibitors.
Subject(s)
Acridines/chemical synthesis , Acridines/pharmacology , Aniline Compounds/chemistry , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , Telomerase/antagonists & inhibitors , Acridines/chemistry , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/metabolism , Fluorescence Resonance Energy Transfer , Protein Binding , Telomerase/metabolismABSTRACT
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.
