Original ArticleDNA-PKcs, a novel functional target of acriflavine, mediates acriflavine's p53-dependent synergistic anti-tumor efficiency with melphalan

- Acriflavine directly binds to DNA-PKcs and inhibits its kinase activity particularly.
- Acriflavine enhances the DNA damage caused by melphalan and exerts synergistic efficacy with melphalan against cancer cells.
- The p53 status dictated the cell fate in response to the combination therapy.

Acriflavine (ACF), a known antibacterial drug, has recently been recognized as a suitable candidate for cancer chemotherapy. However, the molecular target of ACF is not fully understood, which limits its application in cancer therapy. In this study, we established a structure-specific probe-based pull-down approach to comprehensively profile the potential target of ACF, and we identified DNA dependent protein kinase catalytic subunit (DNA-PKcs) as the direct target of ACF. Since DNA-PKcs facilitates the repair process following DNA double-strand breaks, we further developed a drug combination strategy that combined ACF with the bifunctional alkylating agent melphalan, which exerted a p53-dependent synergistic efficacy against human cancer cells both in vitro and in vivo. With these findings, our study demonstrated that structure-specific probe-based pull-down approaches can be used to identify new functional target of drug, and provided novel opportunities for the development of ACF-based antitumor chemotherapies.