Effects of JAI-51 on a panel of glioblastoma cell lines. U118, U138, U373, LN229 cells were cultured for 24 h before the addition of JAI-51 (1 to 10 μM). Cells were used for either cell proliferation tests using MTT at the indicated times (A) or for cell cycle analysis at 24 h (B). (A) After 24 h induction time with 10 μM JAI-51, the decrease in proliferation was statistically significant for all the cell lines tested compared to the untreated cells (P < 0.05 treated versus control), and after 48 h induction time, this decrease in proliferation was also significant with 5 μM JAI-51 for all the cell lines tested (P < 0.05 treated versus control). The results are expressed as the mean ± SD from 3 different experiments. Mitotic index (M.I.) (C, left panel) was determined at 24 h on slide after Papanicolaou staining, and apoptosis (C, right panel) was determined at 48 h using the Annexin V-FITC/PI method (* P < 0.05 treated versus control). (D) Photomicrographs of control LN229 and GL26 cells and cells treated with 10 μM JAI-51 for 24 h (LN229+JAI-51, GL26+JAI-51). Treated LN229 and GL26 cells displayed polylobated nuclei and most of the mitotic figures showed numerous abnormalities (complex spindle with several poles). (Magnification × 600).