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Identification of hypoxia-induced metabolism-associated genes in canine tumors.

ABSTRACT: The energy metabolism of tumors is biased toward glycolysis called as the Warburg effect. The tumor microenvironment is known to be hypoxic, which leads to activating hypoxia-inducible factor 1α (HIF1α) in tumor cells. The high expression of HIF1α plays a functional role in the enhancement of glycolysis and is correlated to poor outcomes in human cancers. However, in dogs, the molecular mechanisms involved in hypoxic tumor cells remain to be elucidated. In the present study, we investigated upregulated genes in hypoxia by RNA-seq analysis, the expression of proteins related to glycolysis in hypoxia by western blotting (WB), and the expression of the monocarboxylate transporter4 (MCT4) in a total of 96 canine tumor tissue by immunohistochemical (IHC) staining. The glycolysis and HIF-1 signaling pathways were upregulated in hypoxic melanoma cells by RNA-seq and WB. In addition, the experiment using HIF1α knockout melanoma cells showed a marker of glycolysis MCT4 was regulated by HIF1α activation. Hypoxia induced high lactate secretion due to the enhancement of glycolysis in canine melanoma cells. IHC analysis revealed membrane-localization of MCT4 protein was observed in urothelial carcinoma and lung adenocarcinoma tissues. We concluded canine MCT4 protein has a role in lactic acid efflux from glycolytic cells and might be a novel marker of hypoxia and glycolysis in canine tumors. This data may also be important in finding a new therapeutic target for MCT4 in the future.

ORGANISM(S): Canis lupus familiaris

PROVIDER: GSE255845 | GEO | 2025/02/14

REPOSITORIES: GEO

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Project description:Published molecular profiling studies in patients with lymphoma suggested the influence of hypoxia inducible factor-1 alpha (HIF1α) targets in prognosis of DLBCL. Yet, the role of hypoxia in hematological malignancies remains unclear. We observed that activation of HIF1α resulted in global translation repression during hypoxic stress in DLBCL. Protein translation efficiency as measured using 35S-labeled methionine incorporation revealed a ≥50% reduction in translation upon activation of HIF1α. Importantly, translation was not completely inhibited and expression of clinically correlated hypoxia targets such as GLUT1, HK2, and CYT-C was found to be refractory to translational repression under hypoxia in DLBCL cells. Notably, hypoxic induction of these genes was not observed in normal primary B-cells. Translational repression was coupled with a decrease in mitochondrial function. Screening of primary DLBCL patient samples revealed that expression of HK2, which encodes for the enzyme hexokinase 2, was significantly correlated with DLBCL phenotype. Genetic knockdown studies demonstrated that HK2 is required for promoting growth of DLBCL under hypoxic stress. Altogether, our findings provide strong support for the direct contribution of HK2 in B-cell lymphoma development and suggest that HK2 is a key metabolic driver of the DLBCL phenotype.ne incorporation revealed a ≥50% reduction in translation upon activation of HIF1α. Importantly, translation was not completely blunted and expression of clinically correlated hypoxia targets such as GLUT1, HK2, and CYT-C was found to be refractory to translational repression under hypoxia in DLBCL cells. Notably, hypoxic induction of these genes was not observed in normal primary B-cells. Translational repression was coupled with decrease in mitochondrial function. Screening of DLBCL patient samples identified that expression of HK2, which encodes for the enzyme hexokinase 2, was significantly correlated with DLBCL phenotype. Genetic knockdown studies show that HK2 is required for promoting growth of DLBCL under hypoxic stress. Altogether, our findings provide more definitive proof of direct contribution of HK2 in development of B-cell lymphoma and suggest that HK2 is a key metabolic driver of DLBCL phenotype.

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Identification of hypoxia-induced metabolism-associated genes in canine tumors.

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