Oxoglutarate dehydrogenase-like inhibits the progression of hepatocellular carcinoma by inducing DNA damage through non-canonical function

Abstract

Oxoglutarate dehydrogenase-like (OGDHL) is considered to be the isoenzyme of oxyglutarate dehydrogenase (OGDH) in the OGDH complex, which degrades glucose and glutamate. OGDHL was reported to reprogram glutamine metabolism to suppress HCC progression in an enzyme-activity-dependent manner. However, the potential subcellular localization and non-canonical function of OGDHL is poorly understood. We investigated the expression of OGDHL and its effect on HCC progression. By employing a variety of molecular biology techniques, we revealed the underlying mechanism of OGDHL-induced DNA damage in HCC cells in vitro and in vivo. AAV loaded with OGDHL exerts therapeutic effect on mouse HCC and prolongs survival time. OGDHL induces DNA damage in HCC cells in vitro and in vivo. We also observed that OGDHL possesses nuclear localization in HCC cells and OGDHL-induced DNA damage was independent of its enzymatic activity. Mechanistically, it was demonstrated that OGDHL binds to CDK4 in the nucleus to inhibit the phosphorylation of CDK4 by CAK, which in turn attenuates E2F1 signaling. Inhibition of E2F1 signaling downregulates pyrimidine and purine synthesis, thereby inducing DNA damage through dNTP depletion. We clarified the nuclear localization of OGDHL and its non-canonical function to induce DNA damage, which demonstrated that OGDHL may serve as a select potential therapeutic target for HCC.