G-Quadruplex-binding benzo[a]phenoxazines down-regulate c-KIT expression in human gastric carcinoma cells

Keith I. E. McLuckie, Z.A.E. Waller, Deborah A. Sanders, David Alves, Raphaël Rodriguez, Jyotirmayee Dash, Grahame J. McKenzie, Ashok R. Venkitaraman, Shankar Balasubramanian

Research output: Contribution to journalArticlepeer-review

142 Citations (Scopus)


There is considerable interest in the structure and function of G-quadruplex nucleic acid secondary structures, their cellular functions, and their potential as therapeutic targets. G-Quadruplex sequence motifs are prevalent in gene promoter regions and it has been hypothesized that G-quadruplex structure formation is associated with the transcriptional status of the downstream gene. Using a functional cell-based assay, we have identified two novel G-quadruplex ligands that reduce the transcription of a luciferase reporter driven from the G-quadruplex-containing c-KIT promoter. We have further shown that endogenous c-KIT expression in a human gastric carcinoma cell line is also reduced on treatment with these molecules. Biophysical analysis using surface plasmon resonance has shown that these molecules preferentially bind with high affinity to one of the two G-quadruplex sequences in the c-KIT promoter over double-stranded DNA. This work highlights the utility of cell-based reporter assays to identify new G-quadruplex binding molecules that modulate transcription and identifies benzo[a]phenoxazine derivatives as potential antitumor agents.
Original languageEnglish
Pages (from-to)2658-2663
Number of pages6
JournalJournal of the American Chemical Society
Issue number8
Publication statusPublished - 4 Feb 2011

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