Figure 1

mIDH1-GL261 cells release 2HG in vitro and are tumorigenic. a RT-PCR analysis shows that IDH1 expression was significantly higher in mIDH1-GL261 compared to control cells. b Western blot analysis of IDH1-R132H expression in transfected GL261 cells after 15, 18 and 24 days of selection. Compared to empty (control cells), the levels of IDH1-R132H are significantly increased. Vinculin was used as housekeeping protein. c GL261 cells over-expressing IDH1-R132H selected for 24 days in the presence of G418 changed morphology compared to control cells. d Proliferation of pGL261 and mIDHI-GL261 as shown by WST proliferation assay performed at four different time points. e mIDH1-GL261 released 2HG in the cell supernatant as evaluated by LC-MS/MS. f mIDH1-GL261 when injected in vivo grew slower than control, however in the later stages the survival curves overlapped (n = 8 mice/group, p = 0.36). g, h, i MRI T2-weighted images confirmed the slower engraftment of mIDH1-GL261 glioma-bearing mice compared with controls at three different times. l RT-PCR performed on explanted gliomas shows that IDH1 overexpression was higher that controls at day 20 and begins to decrease 30 days after tumor implantation. m, n Representative IHC shows the expression of IDH1-R132H in gliomas from mIDH1-GL261 compared to control pGL261-gliomas where expression of IDH1 mutation was totally absent.