Osteosarcoma is a major cause of cancer-related deaths in adolescents. While it thrives in a state of malnutrition, the mechanism of metabolic stress adaptation via metabolic reprogramming is unclear. Here, we found that the level of FAT10, a ubiquitin-like protein, was significantly higher in tumors than in adjacent normal tissues. Moreover, high FAT10 levels were closely related to increased malignancy and shorter survival time in osteosarcoma patients. Multivariate analysis also showed that FAT10 overexpression was an independent predictor of poor prognosis. Functional assays indicated that FAT10 promoted osteosarcoma cell proliferation by inducing glycolysis. In addition, FAT10 knockdown reduced the level of PFKFB3, a positive regulator of glycolysis in many cancers. A positive correlation was found between FAT10 and PFKFB3 levels in osteosarcoma tissues, further indicating that FAT10 induced an increase in glycolysis and that cell growth depended on PFKFB3. Interestingly, FAT10 regulated PFKFB3 expression by directly binding to EGFR and inhibiting its ubiquitination and degradation. These results shed light on the mechanisms responsible for osteosarcoma cell survival in the malnourished tumor microenvironment. Further, the results provide insights into the role of FAT10 in the adaptation of osteosarcoma cells to metabolic stress.
Keywords: EGFR; FAT10; Osteosarcoma; PFKFB3; glycolysis; growth.
AJCR Copyright © 2020.