Reactivation of p53 cannot prevent MCT-1 tumorigenicity. (A) Different types of H1299 cancer cells (control, MCT-1, control + p53, MCT-1 + p53) were inoculated into the athymic nude mice. As indicated with CD31 immunostaining analysis, the vascular index (capillaries/field) was calculated by six randomly selected fields from each tumor biopsy. Tumor weights, hemoglobin amounts, and capillary densities were promoted in the MCT-1 and MCT-1 + p53 xenografts. (B) Immunohistology study of the tumors with CD31 Ab revealed a higher density of microvessels (indicated with arrows) in the MCT-1 and MCT-1 + p53 xenografts than those identified in the control and control + p53 xenografts. (C) Immunohistology data indicated the proteins (brownish) and H&E counterstaining (blue) in the tumors. The basal levels of MCT-1 protein expressed in control and control + p53 samples (a, c). MCT-1 proteins were intensively enhanced in the ectopic MCT-1 tumors (b), whereas the MCT-1 + p53 tumors reduced in MCT-1 concentration (d). The control and MCT-1 tumors were p53 null (e, f). Lower p53 levels were noticed in the MCT-1 + p53 tumors (h) than that of the control + p53 xenografts (g). Cop1, Pirh2 and MDM2 were all enriched in the MCT-1 tumors (j, n, l, p, r). MDM2 was also enriched in the control + p53 xenografts (s), but it was dramatically decreased in the MCT-1 + p53 xenografts (t). (D) The p53 protein was reduced by ectopic MCT-1 in the tumors (lanes 3 vs. 4). Similarly, intrinsic and ectopic MCT-1 quantities were all decreased by p53 restoration (lanes 2 vs. 4). MDM2 levels were promoted after MCT-1 increment (lanes 1 vs. 2) or p53 reactivation (lanes 1 vs. 3). But, MDM2 was comparatively reduced in the concomitant increase of p53 and MCT-1 (MCT-1 + p53) (lanes 3 vs. 4). (E) Consistent with the tumor results, H1299 cells expressing MCT-1 significantly improved MDM2 protein levels (lanes 1 vs. 2), but MDM2 was rather decreased in MCT-1 + p53 sample than control + p53 group. Pirh2 and Cop1 amounts were persistently enriched in the MCT-1 and MCT-1 + p53 backgrounds.