TDZD-8 inhibits PKC and FLT3 in primary AML specimens. (A) Immunoblots for CD34⁺ AML and normal BM specimens to determine PKC phosphorylation. Actin is shown as a loading control. (B) Primary CD34⁺ AML and ALL specimens treated with TDZD-8 for 1 hour were processed to obtain membrane fractions. Immunoblots were performed to determine PKCα and PKCβ levels in the membrane. HSP70 is shown as a control. (C) Titration curve and IC₅₀ value for FLT3 kinase assay. (D) Overlays of flow cytometric analysis for phospho-FLT3 in primary AML specimens. Light gray solid line histograms represent untreated cells. Dotted line histograms represent TDZD-8–treated cells. Gray solid no line histogram represent controls. Cells were processed for analysis 30 minutes after the addition of drug. CD34⁺ (31% inhibition; left panel) and CD34⁺CD38⁻ (29.5% inhibition; right panel) populations.