Cyclin-dependent kinase 9 (CDK9) plays a pivotal role in regulating transcriptional elongation, and has emerged as a promising target in cancer therapy. However, our previous research has demonstrated that CDK9 inhibitors induce abnormal upregulation of H3K27me3 in diffuse large B-cell lymphorma (DLBCL) cell lines, impairing the inhibitory effect on tumor cells proliferatioin. Interestingly, EZH2 inhibitors can reverse the upregulation of H3K27me3, leading to synergistic antitumor effects.

Based on this observation, we designed and synthesized a series of dual inhibitors targeting both CDK9 and EZH2 through fusion based strategies to achieve enhanced antitumor activity.

Among the compounds developed, the potent CDK9/EZH2 dual inhibitor D16 exhibited impressive and balanced inhibitory properties of both targets, with IC50 values of 67 nM for CDK9 and 84 nM for EZH2. Notably, compound D16 induced greater DNA damage and exhibited stronger inhibitory effects on DLBCL proliferation compared to the single-target inhibitor SNS-032 or C24. In addition, D16 showed potent anti-proliferative activities in various solid tumor cell lines, which may provide an innovative strategy for the treatment of cancer.

All these findings highlight the potential of dual CDK9/EZH2 inhibitors as a novel approach for cancer therapy.