Effects of structural modification on the DNA binding properties and photo-induced cleavage reactivity of propargylic sulfones conjugated with an anthraquinone structure.

Propargylic sulfones are known as pH-dependent DNA cleaving agents. We have designed a novel propargylic sulfone conjugated with an anthraquinone structure and evaluated its DNA binding and cleavage characteristics. The propargylic sulfone 3 showed high intercalating ability attributable to anthraquinone chromophore, leading to the efficient alkylation of DNA. The anthraquinone chromophore in 3 also acted as a photosensitizer, and photoirradiation of 3 with DNA induced one-electron oxidation, resulting in the further DNA cleavage. Evaluation of the effect of 3 against EMT6/KU cells revealed that 3 exhibited potent cytotoxicity, even without photoirradiation.