Harmine-based dual inhibitors targeting histone deacetylase (HDAC) and DNA as a promising strategy for cancer therapy

Overexpression of histone deacetylases (HDACs) are observed in different types of cancers, but histone deacetylase inhibitors (HDACIs) have not shown significant efficacy as monotherapy against solid tumors. Recently, studies demonstrated that it is promising to combine HDACIs with DNA damage agents to improve DNA damage level to gain better effect on treating solid tumor. Harmine has been demonstrated to cause DNA damage by intercalating DNA. Therefore, we designed a series of harmine-based inhibitors targeting HDAC and DNA with multi-target strategy, the most potential compound 27 could bind to DNA and cause DNA damage. Furthermore 27 caused cells apoptosis through p53 signaling pathway, and exhibited significant anti-proliferation effects against HCT-116 cells (IC50 = 1.41 μM). As a DNA damage agent, 27 displayed low toxicity in normal cells. Compound 27 was demonstrated as a dual inhibitor targeting HDAC (HDAC1 IC50 = 0.022 μM and HDAC6 IC50 = 0.45 μM) and DNA, and had the potential in the treatment of solid tumor.