LDK is active against malignant lymphoblasts. IC₅₀ values (μM) of indicated treatments by MTT assay after 48-hour incubation are shown in parentheses. (A) Among 5 hit compounds without general cell cycle effects, only Lenaldekar (LDK) had low micromolar activity against human Jurkat T-ALL (IC₅₀ = 0.8μM). (B) LDK chemical structure (1H-indole-3-carbaldehyde quinolin-8-yl-hydrazone). (C) Trypan blue exclusion assay for LDK-treated Jurkat cells. (D) LDK dose-response for 5 human T-ALL lines. (E) LDK dose-response for PBTCs (stimulated with IL-2 30 U/mL), PB B cells (stimulated with IL-10 100 ng/mL), and PB monocytes from healthy human donors, compared with Jurkat. (F) Dose-response for LDK compared with AKT Inhibitor IV for Jurkat, PBTCs, and PB B cells. (G) LDK dose-response for 4 human B-ALL lines. (H) Jurkat T-ALL response to LDK in comparison to glioblastoma (U138), melanoma (Lox), and colon cancer (SW480). (A-H) n ≥ 3, error bars = SEM.