Targeting PDHK1 by DCA to restore NK cell function in hepatocellular carcinoma

Pyruvate dehydrogenase complex is a crucial enzyme involved in the oxidation of glucose. It is regulated by pyruvate dehydrogenase kinase and pyruvate dehydrogenase phosphatase. Studies have demonstrated that pyruvate dehydrogenase kinase 1 (PDHK1), a key enzyme in glucose metabolism, behaves like oncogenes. It is highly expressed in tumors and is associated with poor patient prognosis. However, there is limited research on how PDHK1 affects immune cell function. We have established a model of natural killer (NK) cell exhaustion to investigate the impact of dichloroacetate (DCA) on NK cell function. The production of Granzyme B, IFN-γ, TNF-α, and CD107a by NK cells was explored by flow cytometry. The real-time live cell imaging system was used to monitor the ability of NK cells against tumor cells. The Seahorse analyzer was utilized to measure the oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) of NK cells. The mouse model was used to investigate the potential of combining DCA with adjuvant NK cell infusion. Our study demonstrated that the hepatocellular carcinoma (HCC) microenvironment mediated NK cellular exhaustion, high expression of PDHK1 and reduced cytokine secretion. We discovered that the PDHK1 inhibitor DCA enhances the activity and function of exhausted NK cells infiltrating the tumor microenvironment. Furthermore, in a subcutaneous HCC mouse model, DCA combined with NK cell treatment resulted in retarding cancer progression. This study indicates the potential of DCA in rescuing NK cell exhaustion and eliciting anti-tumor immunity.