Fig. 1

Establishment of PDX resistance. a) Dose response growth inhibition curves for PDX. Growth inhibition curve relative to untreated control of T-ALL cell lines CEM and MOLT4. Cells were treated with various concentration of PDX for 72 h and cell viability was measured using the XTT assay. Individual IC₅₀ values were determined from curve fitting. b) Induction of apoptosis by PDX. After 72 h of PDX treatment at the indicated concentration (CEM and CEM/P cells: 5 nM, MOLT4 and MOLT4/P cells: 10 nM), cells were stained with Annexin V-FITC and PI and analyzed by flow cytometry. The percentage of cells in each group within the gated areas is indicated; the upper right panel represents cells undergoing late apoptosis, and the lower right panel represents cells undergoing early apoptosis. c) PDX induced caspase activation. CEM and MOLT4 cells were treated with PDX (CEM and CEM/P cells: 5 nM, MOLT4 and MOLT4/P cells: 10 nM) for 48 h. Western blots analysis of caspase-3 and PARP cleavage were performed to characterize the apoptotic response. Beta-actin was used to normalized proteins contents and band intensity values are shown below the corresponding band. Results are representative of three independent experiments. PDX, pralatrexate. CEM/P, PDX-resistance CEM cell. MOLT4/P, PDX-resistance MOLT4 cell