Figure 6.

Overexpression of PKM2 accelerates tumor metastasis, COX-2 expression, and EMT in vivo. (A) Representative mouse from each treatment group demonstrating fluorescence signal at day 21 after tumor cell inoculation. Treated with celecoxib, mice showed less fluorescence of GFP in the lungs than in OE-PKM2 mice. (B) HE staining of the lungs of mouse models was performed. (C) Metastatic nodules in the lungs were counted under microscope and quantitatively analyzed. (D) IHC staining detected COX-2, MMP9, and N-cadherin expression in various groups of lung metastatic nodules in a mouse inoculated with PKM2-transduced PC-3 cell. Right: the bar graph shows the relative ratio of staining intensity of COX-2, MMP9, and N-cadherin diaminobenzidine (DAB) in each group. (E) EMT marker, MMP9, and Flag tag protein were detected by Western blotting in lung tissue. (F) Measurements of the levels of PGE2 in the serum of each group. (G) Schematic illustration for PKM2 promotes prostate cancer metastasis through regulating ERK1/2-COX-2 signaling. In prostate cancer, elevated expression of PKM2 interacts with ERK1/2 and contributes to the phosphorylation of ERK1/2, leading to the phosphorylation of subsequent downstream c-Jun and binding to the promoter of cox-2 gene. Upregulation of PGE2 by COX-2 promotes EMT, invasion, and migration of tumor cells. Data represent the mean ± SEM of three independent experiments and were analyzed by one-way ANOVA with multiple comparisons, followed by Dunnett’s post hoc test for significance versus control and presented as mean ± SD. *p < 0.05, **p < 0.01, ***p < 0.001.