Development and structure-activity relationship of tacrine derivatives as highly potent CDK2/9 inhibitors for the treatment of cancer

CDK2/9 are members of the CDKs family, which play key roles in the occurrence and development of many cancers by regulating cell cycle and transcriptional prolongation, respectively. To further optimize and discuss the structure-activity relationships (SARs), a series of tacrine-based compounds were designed and synthesized from the compound ZLWT-37, which was studied by our group previously but no detailed SARs study was conducted on CDK2/9. Among this series, compounds ZLMT-12 (35) exhibited the most potent antiproliferative activity (GI50 = 0.006 μM for HCT116) and superior CDK2/9 inhibitory properties (CDK2: IC50 = 0.011 μM, CDK9: IC50 = 0.002 μM). Meanwhile, ZLMT-12 showed a weak inhibitory effect on acetylcholinesterase (AChE, IC50 = 19.023 μM) and butyrylcholinesterase (BuChE, IC50 = 2.768 μM). In addition, ZLMT-12 can suppress colony formation and migration in HCT116 cells, as well as induce the apoptosis and arrest the cell cycle in the S phase and G2/M phase. In vivo investigations revealed that ZLMT-12 inhibits tumor growth in the HCT116 xenograft tumor model at a low dose of 10 mg/kg without causing hepatotoxicity. The acute toxicity test showed low toxicity with a median lethal dosage (LD50) of 104.417 mg/kg. These findings showed that ZLMT-12 might be used as a drug candidate by targeting CDK2/9.