Introduction>

Cell cycle kinases have been recognized as potential anticancer targets, because loss of regulated cell cycle progression would lead to uncontrolled cell growth and development of cancer. Cdc7 kinase is involved in regulation of the cell cycle and plays important roles in DNA replication. Notably, inhibition of Cdc7 in cancer causes lethal S phase or M phase progression, whereas normal cells can survive, most likely through induction of cell cycle arrest at the DNA replication checkpoints. Therefore Cdc7 kinase has emerged as a promising therapeutic target for the treatment of cancers. Here we present a novel series of furanone derivatives with potent inhibitory effects on Cdc7 kinase.

<Methods>

To identify hit compounds that are insensitive or resistant to high ATP concentration, a high-throughput screening (HTS) was performed in the presence of 100 microM ATP which corresponds to 36-times higher than the Km value of ATP for Cdc7 kinase activity. To characterize inhibitors, ATP dependency and pre-incubation effects were examined. To determine the efficacy of Cdc7 inhibitors, phosphorylation of MCM2 protein in cells were analyzed by western blotting. Selected compounds were subjected to a kinase selectivity panel assay.

<Results>

Only a single hit compound was identified from the HTS, reflecting extremely low hit rate compared to that of other kinase targets in our past HTS. Subsequent hit to lead studies led to the identification of a novel furanone compound as a potential lead compound for further optimization study. Interestingly, these furanone derivatives showed slow-binding inhibition against Cdc7, and exhibited strong inhibitory activity for Cdc7 even in the presence of 1 mM ATP that was added after the pre-incubation of the kinase and compound. Notably this pre-incubation effect was not observed with other kinases tested. Detailed results using cancer cells will also be presented in this poster.

Citation Format: Takayuki Irie, Tokiko Asami, Ayako Sawa, Chika Taniyama, Yoko Funakoshi, Yuko Uno, Hisao Masai, Masaaki Sawa. Discovery of furanone derivatives as novel Cdc7 inhibitors with anti-tumor activity. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr A180.