Discovery of STAT3 and Histone Deacetylase (HDAC) Dual-Pathway Inhibitors for the Treatment of Solid Cancer.

Nowadays, simultaneous inhibition of multiple targets through drug combination is an important anticancer strategy owing to the complex mechanism behind tumorigenesis. Recent studies have demonstrated that the inhibition of histone deacetylases (HDACs) will lead to compensated activation of a notorious cancer-related drug target, signal transducer and activator of transcription 3 (STAT3), in breast cancer through a cascade, which probably limits the anti-proliferation effect of HDAC inhibitors in solid tumors. By incorporating the pharmacophore of the HDAC inhibitor SAHA (vorinostat) into the STAT3 inhibitor pterostilbene, a series of potent pterostilbene hydroxamic acid derivatives with dual-target inhibition activity were synthesized. An excellent hydroxamate derivate, compound 14, inhibited STAT3 (KD = 33 nM) and HDAC (IC50 = 23.15 nM) with robust potency in vitro. Compound 14 also showed potent anti-proliferation ability in vivo and in vitro. Our study provides the first STAT3 and HDAC dual-target inhibitor for further exploration.