Fig. 1.

CD38 deficiency reduces tumor volume and prolongs survival duration of glioma-bearing mice. WT and Cd38^−/− male mice were i.c. injected with 5 × 10³ GL261 cells, and mice brains were scanned by MRI at 17 and 21 days, as described in Materials and Methods. Images of representative WT (upper panel) and Cd38^−/− (lower panel) mice taken at 21 days post-injection are shown in (A) and are displayed from frontal (left) to rostral (right). Tumor volume (B) was calculated, and a repeated-measures ANOVA revealed a significant effect for the genotype (P = .001). Tumor volume was significantly smaller in Cd38^−/− mice at day 21 following injection compared with WT mice (*P = .00001, Fisher's least significant difference post-hoc test). Values are presented as the mean ± SEM (bars) (n = 18 WT and 16 Cd38^−/− mice, respectively). The survival duration of the mice (C) was monitored. A Kaplan–Meier survival analysis of WT and Cd38^−/− by a log-rank test revealed a significant difference between the survival durations of the 2 groups (P = .0003) (n = 18 WT and 16 Cd38^−/− mice, respectively). For the aggressive glioma condition, mice were i.c. injected with 1 × 10⁵ GL261 cells, and MRI was conducted at 10, 14, and 17 days post-injection. Images of representative WT (upper panel) and Cd38^−/− (lower panel) mice taken at 17 days post-injection are shown in (D) and are displayed from frontal (left) to rostral (right). Tumor volume (E) was calculated at 10, 14, and 17 days post-injection. A repeated-measures ANOVA revealed a significant effect for the genotype (P = .01). Tumor volume was significantly smaller in Cd38^−/− mice at day 17 following injection compared with WT mice (*P = .00002, Fisher's least significant difference post-hoc test). Results shown are from a single experiment, and values are presented as the mean ± SEM (bars) (n = 4 WT and 8 Cd38^−/− mice, respectively). (F) Comparison of the tumor volume at day 17 in WT and Cd38^−/− mice. Values in each experiment were normalized to the average tumor volume in WT mice. The results are expressed as the mean ± SEM (bars) of the normalized tumor volumes of all the mice examined in 5 independent experiments (n = 33 WT and 30 Cd38^−/− mice, respectively). The tumor volume was significantly smaller in Cd38^−/− mice (P = .002, Student's t test). The survival duration of the mice (G) was monitored as described in Materials and Methods. A Kaplan–Meier survival analysis of WT and Cd38^−/− by a log-rank test revealed a significant difference between the survival durations of the 2 groups (P = .03) (n = 20 and 17 for WT and Cd38^−/− mice, respectively).