Figure 5. FTY720 sensitizes human NPC cells to radiation in nude mice xenografts.

(A) Twenty days after implantation, the mice were randomly divided into groups that received FTY720, radiation, or a combination of the two, as described in the Materials and Methods section. Tumor volumes were measured on the indicated days. The data points represented the mean tumor volumes ± SD. (B) A photograph of a representative xenograft is shown for each group. (C) Xenograft weights were measured at the time that the mice were sacrificed, and the mice in the combined treatment group showed the most significant reduction in tumor weight. (D) SPHK1 activity was measured in tissue extracts obtained from xenograft tumors. (E) Samples of xenograft tumors obtained from the four groups of mice were subjected to H&E and immunohistochemical staining for Ki-67, p-Akt and Caspase-3. (F) The necrosis grade and expression levels of the Ki-67, p-Akt and Caspase-3 proteins was calculated as necrosis grade and immunohistochemical staining scores. The error bars represent the standard error. *P < 0.05, **P < 0.01.