R428 is a selective Axl inhibitor with an IC50 of 14 nM, more than 50-fold sensitivity for Axl than Abl, Mer, Tyro3, InsR, EGFR, HER2, and PDGFR.
Axl receptor tyrosine kinase transduces signals from extracellular matrix into cytoplasma by binding to the vitamin K-dependent protein growth arrest-specific 6 (Gas6). It is involved in several cellular processes including growth, migration, aggregation and anti-inflammation.
R428 blocks the catalytic activity of Axl, at low nanomolar concentration. [1] Axl-dependent activities, including Akt phosphorylation, cell invasion, proinflammatory cytokine production are inhibited. R428 administration reduces the expression of the cytokine granulocyte macrophage colony-stimulating factor and the epithelial-mesenchymal transition transcriptional regulator Snail. It also inhibits angiogenesis, reduces metastatic tumor burden and extends survival in animal xenograft models. In addition, R428 synergizes with cisplatin to enhance suppression of liver micrometastasis.
R428 can be administrated orally.
References:
[1]Holland SJ, Pan A, Franci C, et al. R428, a selective small molecule inhibitor of Axl kinase, blocks tumor spread and prolong survival in models of metastatic breast cancer. Cancer Res 2010. 70(4): 1544-1554.
