Silencing of OGDHL promotes liver cancer metastasis by enhancing hypoxia inducible factor 1 α protein stability

Hepatocellular carcinoma (HCC) is one of the most common malignant diseases associated with a high rate of mortality. Frequent intrahepatic spread, extrahepatic metastasis, and tumor invasiveness are the main factors responsible for the poor prognosis of patients with HCC. Hypoxia-inducible factor 1 (HIF-1) has been verified to play a critical role in the metastasis of HCC. HIFs are also known to be modulated by small molecular metabolites, thus highlighting the need to understand the complexity of their cellular regulation in tumor metastasis. In this study, lower expression levels of oxoglutarate dehydrogenase-like (OGDHL) were strongly correlated with aggressive clinicopathologic characteristics, such as metastasis and invasion in three independent cohorts featuring a total of 281 postoperative HCC patients. The aberrant expression of OGDHL reduced cell invasiveness and migration in vitro and HCC metastasis in vivo, whereas the silencing of OGDHL promoted these processes in HCC cells. The pro-metastatic role of OGDHL downregulation is most likely attributed to its upregulation of HIF-1 alpha transactivation activity and the protein stabilization by promoting the accumulation of L-2-HG to prevent the activity of HIF-1 alpha prolyl hydroxylases, which subsequently causes an epithelial-mesenchymal transition process in HCC cells. These results demonstrate that OGDHL is a dominant factor that modulates the metastasis of HCC.