Journal: bioRxiv
Article Title: Riboflavin drives nucleotide biosynthesis and iron-sulfur metabolism to promote acute myeloid leukemia
doi: 10.1101/2025.06.26.661633
Figure Lengend Snippet: A . Volcano plot of relative fold change (log 2 ) in metabolite abundance in NB4 cells upon RFK deletion versus Rosa control at day 9 ranked by significance. The dotted line denotes P < 0.05. Blue circles, starch/sucrose/nucleotide sugar metabolism; green circles, nucleotide metabolism; yellow circles, phosphatidylethanolamine/phosphatidylcholine metabolism. B . Dot plot of genetic co-dependency of genes with RFK ranked by Pearson correlation. Data from DepMap 24Q2. Blue shading denotes nucleotide metabolism-associated genes. C . Heatmap of nucleotide metabolites in RFK deleted NB4 cells versus Rosa controls cultured in RPMI for 7 days. Relative log 2 of metabolite abundances shown. Data representative of n =4 biological replicates per condition. D . Western immunoblot for DHODH in NB4 and MV4-11 cells upon genetic KO of RFK for 9 days (left) or 4 and 7 days of exogenous riboflavin starvation (right). β-Actin served as the loading control. Blot membrane was stripped and re-probed for other proteins of interest, and data from the same gel, including loading control, are also used in Figure S5A. E . Schema of CRISPR screen using metabolic library in NB4 cells cultured in Plasmax complete or riboflavin depleted medium. F . Dot plot of genes ranked by relative log 2 enrichment or depletion in Plasmax complete versus riboflavin depleted culture medium as measured by sgRNA abundance. Genes whose abundance increased conferred resistance to riboflavin depletion. Red denotes genes associated with purine biosynthesis. G . Cell number of NB4 cells at day 6 post culture in Plasmax complete or lacking riboflavin and treated with vehicle (water), or cocktails of purine (A+G, adenosine + guanosine) or pyrimidine (C+T, cytidine + thymidine) nucleosides. Cell number normalized to Complete + Vehicle. Data representative of n =3 biological replicates. H . Cell number of MV4-11 cells at day 8 post induction of Rosa or RFK sgRNAs, treated with vehicle (water), or cocktails of purine (A+G, adenosine + guanosine) or pyrimidine (C+T, cytidine + thymidine) nucleosides in Plasmax medium for 4 days. Cell number normalized to sgRosa + Vehicle. Data representative of n =3 biological replicates. I . Western immunoblot for γH2A.X in MV4-11 cells at day 8 post induction of Rosa or RFK sgRNAs, treated with vehicle (water), or cocktails of purine (A+G, adenosine + guanosine) or pyrimidine (C+T, cytidine + thymidine) nucleosides in Plasmax medium for 4 days. Short exposure (top) and long exposure (bottom). Vinculin served as the loading control. J . Dot plot of the correlation between RFK dependency and metabolite abundance in the DepMap 24Q2 dataset ranked by significance. Each circle denotes an individual metabolite. Dotted line denotes P < 0.05. Data are presented as the mean ± SD. ** P < 0.01, *** P < 0.001 and **** P < 0.0001 by ordinary two-way ANOVA with Bonferroni’s multiple comparisons test (G, H).
Article Snippet: D.E.R. generated the metabolic CRISPR screen library at the Broad Institute Genomic Perturbation Platform (GPP) and provided critical technical and conceptual expertise.
Techniques: Control, Starch, Cell Culture, Western Blot, Membrane, CRISPR