Fig. 7

NEURL3 inhibits NPC metastasis in vivo. SUNE1 cells stably expressing HA-NEURL3 or its empty vector were subcutaneously injected into foot pads of mice to establish an inguinal lymph node metastasis model. (a) Representative images of the formed footpad tumors and inguinal lymph nodes. (b-c) Representative images of inguinal lymph nodes (b), and statistical analysis of the volume of lymph nodes (c) between the two groups. Data is shown as mean ± SD, and the p-value was determined by Student’s t-test (*p < 0.05). (d) H&E staining showing the infiltration of tumor cells into skin and muscle of footpad tumors (Scale bar, 100 μm). (e) The infiltration of cancer cells into inguinal lymph nodes as determined by a positive of pan-cytokeratin IHC staining (Scale bar, 2 mm or 20 μm). (f) Comparison of the positive ratios of the inguinal lymph node metastasis between the two groups. P-value was determined by Chi-square test (*p < 0.05). SUNE1 cells stably expressing HA-NEURL3 or its empty vector were inoculating into tail veins of mice to establish a lung metastatic colonization model. (g) Representative images of macroscopic metastatic nodules formed on the lung surfaces of mice in the two groups. (h-i) Representative images (h; Scale bars, 5 mm, 2 mm, and 20 μm) and statistical analysis (i) of metastatic nodules formed in the lungs of mice determined by H&E staining. Data is shown as mean ± SD, and the p-value was determined by Student’s t-test (*p < 0.05). (j) Proposed working model. NEURL3 promotes the degradation of Vimentin protein in a ubiquitin-proteasome pathway, inhibiting NPC metastasis (left). In NPC, promoter hypermethylation of NEURL3 causes its downregulation, enabling increased expression of Vimentin to promote NPC metastasis (right)