Fig 1: IMPDH inhibition causes DNA replication stress and DNA damage in PTEN-deficient T-ALL cells.(A) Immunoblots from indicated cells treated with mycophenolic acid (MPA, 1 μM) for indicated times.(B) Indicated cells were treated with MPA (1 μM, 24 hrs). Cell cycle distribution was quantified by flow cytometry for propidium iodide staining.(C) Indicated cells were treated with MPA (1 μM, 16 hrs) followed by flow cytometry for phosho-H2AXS139 immunostaining, graphed as percent of positive cells.(D, E) Immunoblots on indicated cells treated for 24 hrs with MPA (1 μM) with or without RMC-5552 (1 nM) or MK-2206 (2 μM).(F, G) RNA synthesis measured in indicated cells using the RNA Synthesis Assay kit (Abcam). Cells were treated for 3 hrs with vehicle or actinomycin D (Act. D) and then labeled for 1 hr with 5-ethynyl-uridine (EU), followed by quantification by flow cytometry.(H) Relative abundance of the indicated metabolites, measured by LC-MS/MS, in cells treated with MPA (1 μM, 6 hours), and graphed normalized to vehicle-treated cells.Graphical data are represented as mean ± SEM. *p < 0.05, **p < 0.005, ***p < 0.0005 by unpaired Welch’s t-test.(See also Figure S3).