Figure 5

Pgp and BCRP positive primary AML samples are less sensitive to barasertib-hQPA induced pHH3 inhibition. A, Flow cytometric pHH3 expression in 37 primary AML samples pre-incubated with cytokine cocktail for 48 hours and then treated with 300 nM barasertib-hQPA for 60 minutes. Pgp expression was determined by modulation of R123 efflux and MRK-16 expression. ABCG2 message levels were measured using real-time PCR. B, Scatter plot demonstrating that Pgp positive primary samples are less sensitive to barasertib-hQPA induced pHH3 inhibition than Pgp negative samples (p = <0.001), Mann-Whitney. C, Scatter plot demonstrating that BCRP positive primary samples are less sensitive to barasertib-hQPA induced pHH3 inhibition than BCRP negative samples (p = <0.001), Mann-Whitney.