Fig. 4

Exogenous 2HG enters cells, but is not metabolized at significant levels by 2HG dehydrogenase. a After treating HCT116 R132H/+ cells with U-¹³C 2HG for 24 h, we measured intracellular 2HG by mass spectrometry and found that 35 % was enriched. These data show that exogenous U-¹³C 2HG enters the cells. b An ELISA experiment confirmed that D-2HG dehydrogenase is present in HCT116 R132H/+ cells. c–e More sensitive targeted mass spectrometry methods were applied to measure low levels of isotopic enrichment in central carbon metabolites. f HCT116 parent cells were cultured in 3 mM D-2HG and compared to media preparations without cells as a control for spontaneous non-cellular degradation of 2HG. After 48 h, we found no statistically significant consumption of 2HG from the media (see Table 1). These data support that 2HG is not readily metabolized in HCT116 cells