KX2-391 is a highly selective inhibitor of Src kinase with IC50 value of 20nM [1].
KX2-391 is a non-ATP competitive inhibitor of Src. It is the first inhibitor that targets Src kinase within the substrate binding site. KX2-391 inhibits Src catalyzed trans-phosphorylation of FAK, Shc, paxillin as well as Src kinase autophosphorylation. KX2-391 has no effects on PDGFR, EGFR, JAK1, JAK2 and Lck demonstrating it as a selective inhibitor. It is also found to be an inhibitor of tubulin polymerization through binding to the unique confirmation on heterodimeric tubulin. In cellular assays, KX2-391 shows growth inhibition in NIH3T3/c-Src527F cells and SYF/c-Src527F cells with GI50 values of 23nM and 39nM, respectively [1, 2].
Since Src acts as a regulator in cell proliferation survival, motility and invasiveness, KX2-391 is potent against a variety of solid tumors and many leukemia tumors. It is shown to inhibit primary tumor growth and to suppress metastasis [2].
References:
[1] Fallah-Tafti A, Foroumadi A, Tiwari R, et al. Thiazolyl N-benzyl-substituted acetamide derivatives: Synthesis, Src kinase inhibitory and anticancer activities. European journal of medicinal chemistry, 2011, 46(10): 4853-4858.
[2] Naing A, Cohen R, Dy G K, et al. A phase I trial of KX2-391, a novel non-ATP competitive substrate-pocket-directed SRC inhibitor, in patients with advanced malignancies. Investigational new drugs, 2013, 31(4): 967-973.