Fig. 7: Overexpression of TRIM31 suppresses the tumorigenicity in nude mice models and correlation analysis of TRIM31 and p53 in breast cancer tissues.

a–d About 5 × 10⁶ of ZR-75-30 cells stably overexpressing TRIM31 and control were injected into both backs of mice. The images showed the excised tumors from TRIM31-overexpression ZR-75-30 cells and control cells (a). The growth curve (b), tumor volume (c), and tumor weight (d) of the TRIM31-overexpression group compared with the control group were statistically analyzed at 30 days after injection. e About 5 × 10⁶ of the ZR-75-30 cells stably overexpress TRIM31 or control were injected into nude mice by tail-vein injection. Representative pictures of HE staining of lung tissue (left), the arrows indicated the metastatic nodules on the surface of lung tissues. Bar length: 100 μm. The number of nodules on lung tissues was quantified at 45 days after tail–vein injection (right). f–i About 3 × 10⁶ of ZR-75-30 cells stably express HA-TRIM31, sh-p53, and control (Mock+sh-NC, TRIM31 + sh-NC, Mock + sh-p53, TRIM31 + sh-p53) were injected into mammary fat pads of 6-week old female nude mice. The images showed the tumors from these four groups (f). The growth curve (g), tumor volume (h), and tumor weight (i) of these four groups were statistically analyzed at 40 days after injection. j Representative pictures of HE staining of lung tissues (left), the arrows indicated the metastatic nodules on the surface of lung tissues. Bar length: 100 μm. The number of nodules on the lungs was quantified at 40 days after injection (right). k The expression of TRIM31 and p53 in eight paired breast cancer patient tissues were analyzed by western blot (up). Pearson correlation analysis was used to measure the correlation of TRIM31 and p53 (down). l Representative images of IHC staining of TRIM31 and p53 in normal and breast cancer tissues (up). Bar length: 100 μm. Correlations analysis of the expression of TRIM31 and p53 protein (down). m The model of the antitumor function of TRIM31 in breast cancer progression. In normal cells, the expression of TRIM31 was upregulated. On the one hand, TRIM31 can directly bind to p53 and induce the K63 ubiquitination of p53 to stabilize and activate the p53 signal, on the other hand, TRIM31 can suppress the K48-linked ubiquitination and proteasome degradation of p53 by disrupting the binding of MDM2 and p53. In breast cancer cells, the expression of TRIM31 was downregulated, the p53 was mainly controlled by MDM2 that mediate the K48 polyubiquitination of p53 for degradation.