Design, synthesis and in vitro biological evaluation of 2-aminopyridine derivatives as novel PI3Kδ inhibitors for hematological cancer

Phosphoinositide-3-kinase (PI3K) involves in regulation of proliferation, cell cycle, and apoptosis, and is overexpressed in most of human malignant tumors. Therefore, the development of PI3K inhibitors has attracted great interest in tumor treatment. In this study, we designed and synthesized a series of 2-aminopyridine derivatives via a bioisosterism strategy. Among them, compound MR3278 showed superior PI3Kδ inhibitory activity (IC₅₀ = 30 nM), as well as higher inhibitory activity to most of AML cells (e.g., MOLM-16 and Mv-4-11 cells with IC₅₀ values of 2.6 μM and 3.7 μM, respectively) than Idelalisib. Further cell studies indicated that MR3278 could induce G2/M phase arrests and cell apoptosis of Mv-4-11 cells via PI3K dependent pathway in a dose dependent manner. In addition, in silico physicochemical and ADMET evaluation revealed its drug-like properties with satisfactory toxicity profiles. These results indicate that MR3278 can be identified as a promising new lead compound to the current PI3Kδ inhibitor and is worthy of further profiling.