Abstract: Induction effects of two flavones (chrysin and baicalein) and two flavonols (galangin and kaempferol) on the differentiation of human esophageal squamous cell carcinoma cell line (KYSE-510) were studied in vitro in this paper. The possible structure-activity relationships of these compounds for the induction of differentiation of KYSE-510 cells were explored. The differentiation-specific morphological change of the cells was examined by using phase-contrast microscopy, the augmentation of differentiation marker (cytokeratin 8) was evaluated by confocal laser scanning microscopy, and differentiation marker and the expression of human telomerase reverse transcriptase were quantified by flow cytometry and real-time RT-PCR, respectively. Results revealed that OH at C3′ in the ring C of these compounds might enhance the differentiation-inducing activity, while OH at C6′ in the ring A or at C4′ in ring B might decrease the differentiation-inducing activity.

Key words: flavone, flavonol, human esophageal squamous carcinoma, differentiation