Phosphoenolpyruvate carboxykinase 1 reduces ¹⁸F-FDG uptake in clear cell renal cell carcinoma

Phosphoenolpyruvate carboxykinase (PCK1) plays an important role in gluconeogenesis. Suppressing gluconeogenesis is a component of glucose metabolism change in clear cell renal cell carcinoma (ccRCC). Fluorine 18 (¹⁸F) fluorodeoxyglucose (FDG) positron emission tomography and computed tomography (PET/ CT) is based on the abnormally high rate of glucose metabolism found in cancer cells and is widely used in management of many malignant tumors. However, the relationship between ¹⁸F-FDG uptake and PCK1 expression has not been investigated. Retrospective analysis was conducted on 62 patients with ccRCC who underwent ¹⁸F-FDG PET/CT. The relationship between maximum standardized uptake (SUV_max) and the expression of PCK1 was analyzed with immunohistochemical analysis. PCK1 knockdown and overexpression in ccRCC cells were used to examine the role of PCK1 in tumor metabolism, tumorigenesis, and its effect on the expression of hypoxia inducible factor-1α (HIF-1α). PCK1 inhibits ¹⁸F-FDG uptake and utilization via the HIF-1α pathway. SUV_max is higher in patients with higher-grade ccRCC than in those with lower-grade ccRCC; this result may be due to the lower PCK1 expression in the former. (author)