Fig. 1

A–G. (A) Schematic overview of the enzymatic activity of MTH1 and the proposed mechanism of action of the MTH1 inhibitor TH1579. (B) Representative flow cytometric analysis of expression of CD3 and CD4 in human PMBCs and isolated CD4⁺ T cells, pre- and post-isolation (n = 10). (C) Representative histograms of CD25 surface marker staining on CD4⁺ T cells after 96 h ± CD3/CD28 stimulation (n = 4). (D) Cell proliferation of activated (CD3/CD28) human CD4⁺ T cells, in the abscense or presence of TH1579, was measured by intracellular fluorescent dye dilution (n = 4). (E) Representative flow cytometry dot plots of double stained Annexin V-FITC/Propidium iodine (PI) CD4⁺ T cells for control cells (vehicle), and cells treated with TH1579 (0.5 µM; n = 4). (F) Summary of CD4⁺ T cell apoptosis data (n = 4). (G) Representative images of May Grünwald-Giemsa stained cytospins (scale bar = 5 µm) of human CD4⁺ T cells after 96 h after CD3/CD28 stimulation in the abscense or presence of TH1579. (H) Virtual blot; quantification of MTH1 in human CD4⁺ T cells with or without CD3/CD28 stimulation for 96 h under reduced conditions using Jess automated capillary western blot. Total protein (TP) levels in each sample are presented in % as blue dots. (I) Total peak area of MTH1 detected in Jess, at 25 kDa ± 10%, after total protein normalization (n = 3). The results are displayed as mean ± SD. Statistical comparisons with tree or more groups were performed using one-way ANOVA with Dunnett’s post hoc test comparing the mean of each group to the group treated with 0.05% DMSO. Two-tailed unpaired t-test was used to compare two groups. (****P < 0.0001, ***P < 0.001, **P < 0.01, *P < 0.05)