Figure 8.

SPOP degradation by AURKA promotes tumorigenesis, EMT and enzalutamide-resistance. (A) SPOP overexpression prevents tumor growth in vivo. Growth curves of tumor in nude mice inoculated with C4-2 and SPOP-C4-2 cells on right and left shoulders, respectively. The mean value ± SEM values were from three animals in each group. (B) Representative images of tumor bearing nude mice. Pictures were taken 32 days after injection. (C) Growth curves of tumor obtained from nude mouse injected with C4-2 and 3A-SPOP-C4-2 cells. (D) Representative image showing mouse with tumor. The pictures were taken 32 days following inoculation. (E) Expression of EMT markers in tumor tissues obtained from C4-2 and SPOP-C4-2 cells injected in mice. (F) Histogram shows expression levels of EMT markers in tumor isolated from C4-2 and SPOP-C4-2 injected mice. The data are presented as mean ± SEM values collected from three independent experiments. * p < 0.05 was analyzed using two-way ANOVA. (G) 3A-SPOP-expressing cells are more sensitive to enzalutamide (1 μM, treated for 48 h), compared to WT-SPOP-C4-2 cells. (H) Changes in SPOP levels with treatments of MLN8237 (1 μM, treated for 12 h), and enzalutamide (1 μM, treated for 12 h). (I) Quantification of protein levels as a function of drug treatment obtained from three independent experiments, * p < 0.05, ** p < 0.01. (J) Loss of cell viability with treatments of MLN8237 (1 μM, treated for 24 and 48 h), and enzalutamide (1 μM, treated for 24 and 48 h). Data obtained from three independent experiments, ** p < 0.01. (K) Schematic model depicting the consequences of AURKA-SPOP signaling in CRPC pathogenesis.