In vitro activity: In vitro, Radotinib binds BCR-ABL1 and reduces phosphorylation of CrkL, a BCR-ABL1 target protein. Radotinib also effectively inhibits the proliferation of common mutant clones of BCR-ABL1, with the exception of T315I. In AML cells, radotinib significantly decreases the cell viability, promotes differentiation, and induces CD11b expression and apoptosis. In NB4, THP-1, and Kasumi-1 cells, radotinib also induces CD11b expression, and decreases the viability.

Kinase Assay: Radotinib (formerly also known as IY-5511) is a novel, potent, selective, orally bioavailable, and second-generation BCR-ABL1 tyrosine kinase inhibitor with IC50 of 34 nM.

Cell Assay: Cells (BMCs of AML and CML patients, NB4, HL60, KASUMI-1, and THP-1 cells) are seeded in 96-well plates at a density of 2×104 cells/ml with 100 μL of medium per well and then incubated with various concentrations of radotinib (0, 1, 10, and 100 μM) for 72 h at 37°C. The CellTiter 96 solution (20 μL) is added directly to each well and plates are incubated for 4 h in a humidified 5% CO2 atmosphere at 37°C. Absorbance is measured with a PowerWave XS2 Microplate Spectrophotometer at 490 nm and the results are expressed as percentage changes from the basal condition using four to five culture wells for each experimental treatment. In some experiments, HL60 cells are cultured with 100 nM ATRA and 1 μM dasatinib for 4 days, and 10 μM radotinib is added to each group according to the planned schedule

Haematologica. 2014 Jul;99(7):1191-6; PLoS One. 2015 Jun 12;10(6):e0129853.