Colorectal anticancer activities of polymethoxylated 3-naphthyl-5-phenylpyrazoline-carbothioamides.

To develop potent chemotherapeutic agents for treating colorectal cancers, polymethoxylated 3-naphthyl-5-phenylpyrazoline-carbothioamide derivatives were designed. Twenty-two novel derivatives were synthesized and their cytotoxicities were measured using a clonogenic long-term survival assay. Of these derivatives, 3-(1-hydroxynaphthalen-2-yl)-N-(3-methoxyphenyl)-5-(4-methoxyphenyl)-pyrazoline-1-carbothioamide (NPC 15) exhibited the best half-maximal cell growth inhibitory concentrations (196.35nM). To explain its cytotoxicity, further biological experiments were performed. Treatment with NPC 15 inhibited cell cycle progression and triggered apoptosis through the caspase-mediated pathway. Its inhibitory effects on several kinases participating in the cell cycle were investigated using an in vitro kinase assay. Its half-maximal inhibitory concentrations for aurora kinases A and B were 105.03μM and 8.53μM, respectively. Further analysis showed that NPC 15 decreased phosphorylation of aurora kinases A, B, and C and phosphorylation of histone H3, a substrate of aurora kinases A and B. Its molecular binding mode for aurora kinase B was elucidated using in silico docking. In summary, polymethoxylated 3-naphthyl-5-phenylpyrazoline-carbothioamides could be potent chemotherapeutic agents.