N‑Myc downstream‑regulated gene 2 restrains glycolysis and glutaminolysis in clear cell renal cell carcinoma

Glycolysis and glutaminolysis are heavily involved in the metabolic reprogramming of cancer cells. The activation of oncogenes and inactivation of tumor suppressor genes has a marked effect on the cellular metabolic processes glycolysis and glutaminolysis. N-Myc downstream-regulated gene 2 (NDRG2) is a tumor suppressor gene that previous studies have demonstrated can inhibit the growth, proliferation and metastasis of clear cell renal cell carcinoma (ccRCC) cells. However, the function of NDRG2 in ccRCC metabolism remains unknown. In the present study, NDRG2 significantly inhibited the consumption of glucose and glutamine, as well as the production of lactate and glutamate in ccRCC. NDRG2 significantly suppressed the expression of glucose transporter 1, hexokinase 2, pyruvate kinase M2, lactate dehydrogenase A, glutamine transporter ASC amino acid transporter 2 and glutaminase 1 at the mRNA (by quantitative polymerase chain reaction) and protein level (by western blot analysis), all of which are key regulators and enzymes in glycolysis and glutaminolysis. Data from the present study also revealed that overexpression of NDRG2 suppressed cell proliferation in ccRCC in vitro and in vivo , demonstrated by colony formation assays, wound healing assay and nude mouse transplantation tumor experiment. The present findings demonstrate for the first time that NDRG2 acts as a key inhibitor of glycolysis and glutaminolysis in ccRCC and could be a promising target for the metabolic treatment of ccRCC.