KS15 is an inhibitor of the interactions between cryptochromes (CRYs: CRY1 and CRY2) and the CLOCK:BMAL1 heterodimer. KS15 impairs the feedback actions of CRYs on E-box-dependent transcription (EC50=4.9 μM) by CLOCK:BMAL1 heterodimer, an indispensable transcriptional regulator of the mammalian circadian clock. Anti-proliferative activity[1][2].
Applications of KS15 at different concentrations from 1 μM to 10 μM restored the E-box-driven luciferase activities in a dose-dependent manner, indicating that KS15 evidently impairs the suppressive actions of CRYs on CLOCK:BMAL1-induced transcription. KS15 inhibits the interactions between CRYs and BMAL1, resulting in the enhanced transcriptional activity in the core loop of the molecular circadian clock[1].KS15 directly binds to the C-terminal region of cryptochromes (CRYs: CRY1 and CRY2) and enhances E-box-mediated transcription[2].KS15 decreases the speed of cell growth and increased the chemosensitivity of MCF-7 cells to Doxorubicin and Tamoxifen. KS15 exerts an anti-proliferative effect and increases sensitivity to anti-tumor drugs in a specific type of breast cancer[2].
[1]. Chun SK, et al. A synthetic cryptochrome inhibitor induces anti-proliferative effects and increases chemosensitivity in human breast cancer cells. Biochem Biophys Res Commun. 2015;467(2):441-446.
[2]. Jang J, et al. The cryptochrome inhibitor KS15 enhances E-box-mediated transcription by disrupting the feedback action of a circadian transcription-repressor complex. Life Sci. 2018;200:49-55.