Figure 6.

XAF1 expression correlated with TMZ induced apoptosis in vivo. Mouse GBM xenografts were set up by injecting 4 × 10⁶ GBM wild type control (WT) or XAF1 silenced (XAF1-KD) cells on the left and right flank, respectively, of the same mice. Three weeks later, mice were treated with either 50 mg/kg of TMZ orally or vehicle control daily for 7 days. Mice were then injected with 50 μ L NIR-FLIVO747 via the lateral tail vein, 4 hours later, mice were imaged using the PerkinElmer FMT2500 to compare tumor cell apoptosis on both sides. (a) For each mouse, left flank: wild type cells, right flank: XAF1 silenced (XAF1-KD) cells. (b) Average fluorochrome concentration in the tumor area on both sides. Error bar represent the mean ± SD; n = 5, with significance *p < 0.05 by Student’s t-test. (c) Tumor growth curves of U251/T98G control and XAF1 silenced (XAF1-KD) tumors. (d) Mice were sacrificed and tumor tissue on both sides was isolated, cut and fixed in 10% neutral formalin. Cleaved Caspase-3 immunohistochemistry was performed as described in the Material and Methods section. From left to right: U251 wild type (U251 WT), U251 XAF1 silenced (XAF1-KD), T98G wild type (T98G WT) and T98G XAF1 silenced (XAF1-KD) tumors. 5 mice were included in this study and similar results were observed in each animal.