Mitogen-activated protein kinase–interacting kinases (MNKs) play a key role in the occurrence and migration of tumors and have become promising targets for tumor therapy. Nevertheless, the development progress on the MNKs inhibitors against cancer was relatively slow. In this study, compound 4s (MNK1/2 half-maximal inhibitory concentration [IC 50 ] = 987/1048 nM), a promising MNKs inhibitor was discovered based on virtual screening. After the structural optimization of compound 4s , 18 novel thiophene [2,3-D] pyrimidine–thiazole derivatives were designed and prepared, and their inhibitory effect on MNKs was determined. Among which, compound 5l exhibited the best inhibitory activity on MNKs (MNK1/2 IC 50 = 23/62 nM) and relatively high selectivity among 125 kinases. Results from in vitro experiments indicated that compound 5l could significantly inhibit the in vitro proliferation (IC 50 = 0.8 ± 0.1 μM) and migration of breast cancer cells, which demonstrated that compound 5l is a promising MNK inhibitor to treat breast cancer and need further study.
Mitogen-activated protein kinase-interacting protein kinases (MNKs) and phosphorylate eukaryotic initiation factor 4E (p-eIF4E) play a critical role in regulating mRNA translation and protein synthesis associated with the development of cancer, metabolism, and inflammation. This study undertakes the modification of a 4-(3-(piperidin-4-yl)-1H-pyrazol-5-yl)pyridine structure, leading to the discovery of 4-(3-(piperidin-4-yl)-1H-pyrazol-5-yl)-1H-pyrrolo[2,3-b]pyridine (D25) as a potent and selective MNK inhibitor. D25 demonstrated inhibitory activity, with IC50 values of 120.6 nM for MNK1 and 134.7 nM for MNK2, showing exceptional selectivity. D25 inhibited the expression of pro-inflammation cytokines in RAW264.7 cells, such as inducible NO synthase, cyclooxygenase-2, and interleukin-6 (IL-6). In the lipopolysaccharide-induced sepsis mouse model, D25 significantly reduced p-eIF4E in spleen tissue and decreased the expression of tumor necrosis factor α, interleukin-1β, and IL-6, and it also reduced the production of reactive oxygen species, resulting in improved organ injury caused by inflammation. This suggests that D25 may provide a potential treatment for sepsis and sepsis-associated acute spleen injury.