Fig. 5: GSH biosynthesis limits formaldehyde toxicity.

a Resazurin-based viability assay in Wild type (WT) and ∆ADH5 Nalm6 cells in the presence of different concentrations of formaldehyde (FA) with or without 50 μmol L⁻¹ L-buthionine-sulfoximine (L-BSO) for five days (mean ± SEM, n = 6). µM refers to µmol L⁻¹. b Resazurin-based viability assay performed with WT, ∆ADH5, ∆GCLM and ∆ADH5 ∆GCLM (n = 7) HCT116 cells and with the complemented cell lines ∆GCLM/pGCLM (pGM) and ∆ADH5 ∆GCLM/pGCLM (pGM) (n = 6) in response to 0, 15, 30, 60, 90, 120, 150 and 180 μmol L⁻¹ FA (n = 6, mean ± SEM, two-way ANOVA, Tukey´s multiple comparison test, WT vs ∆GCLM: **P = 0.0038 (150 µmol L⁻¹ FA), **P = 0.0097 (180 µmol L⁻¹ FA); ****P < 0.0001). c Representative images of HCT116 3D-spheroid formation for WT, ∆ADH5, ∆GCLM, and ∆ADH5 ∆GCLM cells in the presence of FA at day 5 after seeding (scale bar 0.5 mm). d Representative images of the colony formation assay performed with WT, ∆ADH5, ∆GCLM, and ∆ADH5 ∆GCLM HCT116 cells in six-well plates in the presence of the indicated concentration of FA. e Quantification of the colony formation assay shown in (d) (n = 5, mean ± SEM, one-way ANOVA using a Tukey´s multiple comparison test, ***P = 0.0003).