Biological Activity
R406 is a competitive Syk inhibitor for ATP binding with a Ki of 30 nM, potently inhibits Syk kinase activity in vitro with an IC50 of 41 nM, measured at an ATP concentration corresponding to its Km value.
In Vitro
R406 also exhibits antagonistic activity for adenosine A3 receptor with an IC50 estimated to be 93 nM[1]. In Ramos B lymphoma cells, B-cell receptor (BCR) crosslinking induces robust phosphorylation of B-cell linker protein (BLNK), which is ablated by addition of the Syk inhibitor R406. Additionally, R406 significantly reduces constitutive Syk signaling in EBV+ cell lines derived from patients with Post-transplant lymphoproliferative disorder (PTLD), termed SLCL. Therefore, R406 inhibits Syk activation[2].
In Vivo
Prophylactic treatment of mice with R406 administers 1 h before immune complex challenge reduces the cutaneous reverse passive Arthus reaction by approximately 72 and 86% at 1 and 5 mg/kg, respectively, compared with the vehicle control. The net optical density reading of extravasated dye extracted after treatment with R406 at 1 or 5 mg/kg R406 is reduced from 0.14 (vehicle) to 0.04 or 0.02, respectively (p<0.01)[1].
References & source
Published experimental findings depend on the model and assay conditions. They do not guarantee equivalent performance in every application. For laboratory research use only.