HepaCAM Regulates Warburg Effect of Renal Cell Carcinoma via HIF-1α/NF-κB Signaling Pathway

Abstract

ObjectiveTo investigate how hepatocyte cell adhesion molecule (hepaCAM) regulates cancer energy metabolism through hypoxia-inducible factor (HIF-1α) in renal cell carcinoma (RCC). Materials and MethodsThe expression of hepaCAM and HIF-1α in RCC tissue samples was examined by immunohistochemistry. Glucose consumption and lactate production assays were used to detect metabolic activity in RCC cell lines. P65 and IκB kinase (IKKβ) mRNA and protein expression were detected using quantitative real-time polymerase chain reaction and western blotting, respectively. Nuclear translocation of P65 was observed by immunofluorescence staining after re-expressing hepaCAM. The luciferase reporter assay was applied to validate the transcriptional activity of HIF-1α. ResultsHIF-1α expression was elevated and hepaCAM suppressed in RCC compared with adjacent normal tissues. Furthermore, hepaCAM re-expression significantly decreased glycolytic metabolism in RCC cell lines, and reduced HIF-1α, IKKβ, and P65 expression. The expression of HIF-1α, GLUT1, LDHA, and PKM2 were further reduced with combined hepaCAM overexpression and treatment with the NF-κB inhibitor BAY11-7082, compared to hepaCAM overexpression alone. Additionally, hepaCAM decreased the transcriptional activity of HIF-1α and blocked P65 nuclear translocation by the NF-κB pathway. ConclusionOur data suggest that hepaCAM suppresses the Warburg effect via the HIF-1α/NF-κB pathway in RCC, which is a facilitating factor in hepaCAM-reduced tumorigenesis.