Selective recognition of c-myc promoter G-quadruplex and down-regulation of oncogene c-myc transcription in human cancer cells by 3,8a-disubstituted indolizinone

C-myc promoter G-quadruplex is a very important target for developing anti-cancer drugs. However, highly selective recognition of DNA c-myc G-quadruplex with parallel configuration is also a very challenging problem. Here, we showed a new type of N-containing alkaloid, 3,8a-disubstituted indolizinone, which adopted a distorted configuration. 6-Methyl-3-(naphthalen-2-yl)-8a-(4methylpyridin- 2-yl)-indolizinone could selectively recognize DNA c-myc G-quadruplex leading to an obvious fluorescence enhancement by 11-fold, and meanwhile the G-quadruplex can be stabilized up to 90 degrees C. Further, it could down-regulate the transcription of oncogene c-myc in both human non-small cell line (A549) and human laryngeal epithelial cell line (Hep-2).