Figure 3.

MERTK inhibition has functional antitumor effects in ETP-ALL cell lines and T-ALL patient samples. (A) Loucy or PEER cells were plated in triplicate at 20,000 cells/well and cultured for 24 h; then, they were treated with vehicle (DMSO) or MRX-2843 at the indicated concentrations for an additional 48 h. After treatment, cells were stained with Presto Blue reagent, fluorescence was measured, and cell numbers were calculated relative to the DMSO control. IC₅₀ values were determined by nonlinear best-fit regression analysis. Mean values ± SEM were derived from three independent experiments. (B,C) Loucy (B) or PEER (C) cells were plated at 300,000 cells/well and cultured for 24 h, and then treated with vehicle or MRX-2843 at the indicated concentrations for an additional 48 h. After treatment, cells were stained with PO-PRO-1 iodide and propidium iodide dye uptake was assessed by flow cytometry. Mean values ± SEM were derived from 3–4 independent experiments (* p < 0.05, one-way ANOVA). (D–F) T-ALL patient samples were cultured with UNC2025, a close analogue of MRX-2843, and relative cell numbers were assessed using MTS reagent. (E) Patient samples obtained from patients aged 0–18 years. (F) Patient samples obtained from patients aged 15–39 years. Abbreviations: AYA—adolescent and young adult.