Cancer Management and Research (Oct 2021)
Targeted Inhibition of HK-II Reversed the Warburg Effect to Improve the Radiosensitivity of Laryngeal Carcinoma
Abstract
Xiao-Hong Chen,1 Ding-Li Yu,2 Jiang-Tao Zhong,2 Shui-Hong Zhou,2 Jun Fan,3 Zhong-Jie Lu4 1Department of Otolaryngology, The Second Hospital of Jiaxing (The Second Affiliated Hospital, Jiaxing University), Jiaxing City, Zhejiang Province, 314000, People’s Republic of China; 2Department of Otolaryngology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, 310003, People’s Republic of China; 3State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, 310003, People’s Republic of China; 4Department of Radiotherapy, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, 310003, People’s Republic of ChinaCorrespondence: Shui-Hong ZhouDepartment of Otolaryngology, The First Affiliated Hospital, College of Medicine, Zhejiang University, 79 Qingchun Road, Hangzhou, 310003, People’s Republic of ChinaTel +86-571-87236894Fax +86-571-87236895Email [email protected]: Hexokinase-II (HK-II) is the key enzyme in the first rate-limiting step of glycolysis that catalyzes the conversion of glucose to glucose-6-phosphate. Here, we examined the association between HK-II expression and radioresistance in laryngeal carcinoma and whether the inhibition of HK-II expression can enhance the radiosensitivity of these tumors.Methods: The effects of HK-II small interfering RNA (siRNA) on the radiosensitivity of Tu212 cells were examined in vitro and in vivo in a mouse model. Cells were irradiated using a 6-MV linear accelerator. The cell viability, cell survival, proliferation, apoptosis, and cell cycle of Tu212 cells were evaluated using trypan blue staining, colony formation assays, CCK-8 assays, and flow cytometry, respectively. Oxygen consumption, lactic acid production, glucose consumption, and the ATP level of Tu212 cells were also examined. The expression of glycolytic and regulatory enzymes involved in the tricarboxylic acid cycle was assessed using Western blotting.Results: The HK-II siRNA and X-ray combination treatment led to a significantly greater reduction of cell viability, inhibition of cell survival and proliferation, increased apoptosis, and increased G2 phase arrest compared to either treatment alone (all, P< 0.01). HK-II siRNA increased the oxygen consumption rate of cells, significantly inhibited lactic acid production and glucose consumption, and significantly suppressed the upregulation of HK-II, pyruvate kinase M2 (PKM2), pyruvate dehydrogenase (PDH), phosphofructokinase platelet (PFKP), lactate dehydrogenase (LD), and citrate synthase (CS) (all, P< 0.01).Conclusion: The inhibition of HK-II by siRNA enhances the radiosensitivity of laryngeal carcinoma Tu212 cells by inhibiting glycolysis and partially inhibiting oxidative phosphorylation.Keywords: laryngeal carcinoma, hexokinase-II, siRNA, radiosensitivity, Warburg effect
