Fig. 5: TH9619 and hypoxanthine causes 10-CHO-THF accumulation.
From: Formate overflow drives toxic folate trapping in MTHFD1 inhibited cancer cells
a,b, HCT116 (a) and SW620 (b) cells were grown as spheroid cultures in three dimensions. Proliferation was measured as spheroid area from day 0 to 5 on 1 µM TH9619 or vehicle, means ± s.d. (n = 3 for HCT116 and n = 2 for SW620). Representative pictures shown for both cell lines. Scale bars, 500 μm. c, In the folate trapping model, hypoxanthine is converted to IMP, GMP or AMP by purine salvage, causing feedback inhibition on de novo purine synthesis. Simultaneously, TH9619 inhibits MTHFD1(DC), which together blocks consumption of 10-CHO-THF, creating a folate trap and preventing thymidylate synthesis due to exhaustion of THF. d, 10-CHO-THF levels normalized to PCV in SW620 WT and MTHFD2−/− cells treated for 24 h with 1 μM TH9619 and 50 μM hypoxanthine (cultured in RPMI-dFBS), means ± s.d. (n = 3); one-way ANOVA with Tukey’s multiple comparisons test. e, LC–MS chromatograms for one representative experiment of d. RT, retention time.
