Fig. 3. SLC19A2 expression is a determinant of growth at physiologically relevant thiamine concentrations.

(A) Log₂ fold change in abundance since initial pool, of DNA barcodes representing indicated cell lines in a competition assay, for cells grown in the absence of thiamine (−thiamine), relative to growth responses in the presence of 3 μM thiamine (+thiamine) (mean ± SD, n = 3 independent barcodes). Media were supplemented with 10% dialyzed FBS (dFBS), which contributes ~1 nM thiamine. (B) Low-thiamine cell competition responses were correlated with CCLE mRNA expression data of metabolic genes, and thiamine transporter 1 (SLC19A2), but not thiamine transporter 2 (SLC19A3), had one of the top-scoring Pearson’s correlation coefficients. TPM, transcripts per million. (C) Left: Gene scores for a CRISPR screen done with Jurkat cells in the presence (+thiamine) or absence (−thiamine) of 3 μM thiamine. Media were supplemented with 10% dialyzed FBS, which contributes ~1 nM thiamine. Most genes gave similar scores in the two conditions. Right: The top 10 genes differentially required in low thiamine are shown. (D) Log₂ fold change in the abundance of individual sgRNAs in our CRISPR screen, in the presence (+thiamine) or absence (−thiamine) of 3 μM thiamine, for SLC19A2 (top) and SLC19A3 (bottom). (E) Baseline mRNA levels by real-time quantitative polymerase chain reaction (RT-qPCR) of indicated genes for cell lines representing the following cancers: T-ALL (JURKAT), B-ALL (RCH-ACV, KOPN8, REH, and NALM6), diffuse large B cell lymphoma (SUDHL4), and Burkitt lymphoma (ST486). ND, not detected (mean ± SD, n = 3).