Fig. 7

CircECE1 positively regulates glucose metabolism in a xenograft model. a. 143B cells stably expressing CircECE1 WT, MUT, or empty vector were subcutaneously injected into nude mice. Nude mice were respectively injected with an equal amount of 5 × 10⁶ stable control cells or cells transfected with CircECE1 WT or MUT subcutaneously. After 30 days, tumors were dissected and photographed. b. Tumor weight was calculated on the day mice were euthanized. Data represent the mean ± SEM (n = 6 each group). c. Tumor volumes (ab2/2) were recorded every six days beginning on the day after mice were injected with the stable OS cells. Data represent the mean ± SEM (n = 6 each group). d. Western blotting was used to assess protein expression levels. Expression of the rate-limiting enzymes GLUT1, GLUT4, MCT4, PDK1, and PDK4 was decreased in tumors formed by CircECE1 overexpression in osteosarcoma cells. e. RT-qPCR revealed that the mRNA levels of the rate-limiting enzymes GLUT1, GLUT4, MCT4, PDK1, and PDK4 were decreased in tumors formed by CircECE1 overexpression in osteosarcoma cells. f. H&E staining and immunohistochemistry (IHC) revealed the structure of OS in mice and the relative protein levels of GLUT1, GLUT4, MCT4, PDK1, and PDK4 in tumors of different groups. Scale bars = 100 μm. g. Lung metastasis in mice injected with various stable 143B cells in the tail vein was detected using an in vivo bioluminescence imaging system. Representative images and a histogram are shown (n = 9 each group). h. Fish revealed the expression level of CircECE1 and Immunohistochemistry (IHC) revealed the relative protein levels of GLUT1, GLUT4, MCT4, PDK1, and PDK4 in chondroma and osteosarcoma. Scale bars = 100 μm. I. Schematic illustration of the CircECE1/c-Myc/TXNIP axis