TRIB2 supports a high glycolytic phenotype in melanoma cells

Background Metabolic adaptation is a crucial driver of melanoma progression and therapy resistance. The pseudokinase Tribbles homolog 2 (TRIB2) is highly expressed in melanoma and is associated with poor outcomes and treatment resistance. However, its specific role in the metabolic profile of melanoma cells remained unexplored. This study aimed to investigate the impact of TRIB2 on cellular metabolism, and its role in metabolic adaptation in melanoma. Materials and methods The study used UACC-62 human melanoma cells with high endogenous TRIB2 expression and isogenic TRIB2-knockout (KO) clones generated via CRISPR-Cas9. Cell proliferation was assessed using trypan blue exclusion assays under treatment with metabolic drugs including 2-deoxyglucose (2-DG), and dichloroacetate (DCA). Metabolic phenotypes were evaluated by measuring glucose consumption, lactate production, and real-time analysis of glycolytic flux (ECAR) and mitochondrial respiration (OCR) using a Seahorse bioanalyzer. Reactive oxygen species (ROS) levels were measured by dihydroethidium (DHE) fluorescence. Gene expression was analyzed by qPCR, and protein levels were determined by western blot. Citrate synthase activity was measured enzymatically. Results TRIB2-KO cells exhibited significantly reduced basal proliferation compared with wild-type (WT) cells. KO cells were also more sensitive to the glycolytic inhibitor 2-DG. Conversely, WT cells were more susceptible to DCA treatment. Metabolic analyses confirmed that TRIB2-KO cells had lower glucose consumption, lactate production, and glycolytic capacity than WT cells. Mitochondrial respiratory function and the protein levels of key respiratory complexes were unchanged. Despite the reduction in glycolytic activity, TRIB2 depletion did not increase mitochondrial respiratory capacity and was associated with elevated basal intracellular superoxide levels. Among the molecular alterations identified, PDK4 was consistently reduced at both the mRNA and protein levels, whereas citrate synthase activity was significantly decreased despite preserved protein abundance, indicating selective alterations in mitochondrial carbon metabolism. Conclusions TRIB2 expression promotes a glycolytic phenotype and contributes to metabolic adaptation in melanoma. Loss of TRIB2 does not induce a metabolic shift towards oxidative phosphorylation but instead results in broader metabolic rewiring characterized by reduced glycolysis together with selective alterations in mitochondrial carbon metabolism. These findings identify the TRIB2–PDK4 axis as a previously unrecognized component of metabolic regulation in melanoma and provide a rationale for further investigating its therapeutic potential.