Exploration of Janus Kinase (JAK) and Histone Deacetylase (HDAC) Bispecific Inhibitors Based on the Moiety of Fedratinib for Treatment of Both Hematologic Malignancies and Solid Cancers

The feedback activation of the Janus kinase (JAK)–STAT pathway leads to the fact that solid cancers are not sensitive to histone deacetylase (HDAC) inhibitors. Herein, a series of novel 2-amino-4-phenylaminopyrimidine JAK/HDAC dual-target inhibitors based on the moiety of fedratinib were designed and synthesized. Among them, 21 and 30 potently inhibited HDAC3/6 and JAK1/2 at nanomolar levels and exhibited splendid selectivity for the JAK2 against a panel of 76 kinases. 21 and 30 presented remarkable antiproliferative activity in both hematological malignancies and solid cancers, which was endorsed by JAK–STAT and HDAC pathway blockade and proapoptotic activity. On the basis of great plasma stability and oral bioavailability, 21 and 30 effectively suppressed the tumor growth of HEL and A549 xenograft models. Collectively, the above results validate that JAK/HDAC dual-target inhibitors provide valuable clues for targeted treatment of hematological malignancies and solid cancers.