Figure 1.

Proliferation of ponatinib-resistant chronic myeloid leukemia cells in the absence of BCR-ABL kinase activity. KCL22 (wild-type BCR-ABL), KCL22^T315I, and KCL22^Pon-Res cells were cultured with or without (Untr) increasing concentrations of ponatinib and 150 nM dasatinib. Proliferation was measured by cell counting using a glass hemocytometer following 24, 48, and 72 hours of drug treatment, and IC50 values were calculated using GraphPad Prism software (A). To assess for BCR-ABL activity, the levels of phosphorylation of CRKL were measured by immunoblot following four hours of drug treatment at varying concentrations of ponatinib and 150 nM dasatinib (B). Error bars = SD. Two independent experiments were performed in triplicate. Untr = untreated.