Design, synthesis, biological evaluation and molecular modeling of novel 1H-pyrazolo[3,4-d]pyrimidine derivatives as BRAF and VEGFR-2 dual inhibitors.

Aiming to explore novel BRAF and VEGFR-2 dual inhibitors, a series of 1H-pyrazolo[3,4-d]pyrimidine derivatives were designed, synthesized and biologically evaluated in this study. Most of the synthesized 1H-pyrazolo[3,4-d]pyrimidine compounds displayed moderate to high potent activity in both enzymatic and cellular proliferation assays. Among these compounds, 9e, 9g, 9m and 9u showed remarkably high inhibitory activities against both BRAF and VEGFR-2 kinase comparable to positive control Sorafenib. Particularly, compound 9u also showed potent anti-proliferative activity against BRAF-expressing A375 (IC = 1.74 μM) and H-29 (IC = 6.92 μM) as well as VEGFR-2-expressing HUVEC (IC = 5.89 μM), which was also comparable to Sorafenib. Furthermore, kinase selectivity profile showed that 9u had almost poor or no significant inhibitory activity against wild-type BRAF and 15 other tested protein kinases. Flow cytometric analysis showed that compound 9u mainly arrested the A375 and HUVEC cell lines in the G/G stage with a concentration-dependent effect. In addition, the molecular docking and molecular dynamics simulations suggested that 9u adopted a similar binding pattern with Sorafenib at the ATP-binding sites of BRAF and VEGFR-2. Taken together, these results indicated that compound 9u may serve as novel lead compound in research on more effective BRAF and VEGFR-2 dual inhibitors.