Influence of oxygen availability on expression of glutaminolysis genes in human colon cancer cells

Abstract

Abstract Introduction Glutaminolysis, beside glycolysis, is a key metabolic pathway of a cancer cell that provides energy and substrates for the synthesis of nucleic acids, proteins, and lipids. The pathway is mediated by both mitochondrial and cytosolic enzymes. Neither expression of glutaminolysis enzymes in colon cancer cells nor the influence of various oxygen concentrations on their expression has been studied so far. Objectives The aim of the study was to determine and compare the mRNA expression of enzymes involved in glutaminolysis at various oxygen levels in human primary (SW480) and metastatic (SW620) colon cancer cells cultured in 1% O2 (hypoxia), 10% O2 (tissue normoxia), 21% O2 (atmospheric normoxia). Methods Cell viability was determined by Trypan Blue exclusion (TB) and Thiazolyl Blue Tetrazolium Bromide (MTT). The expression of HIF1α, GLUT1, GLS1, AST1, AST2, ACL, PC and GC1, GC2 at mRNA levelwas determined by RT-qPCR. Results. Correlation between increasing oxygen concentration and cell count was not observed. In both cell lines the number of viable cells was the lowest at 10% oxygen. The enzyme profile and expression of proteins involved in glutaminolysis varied depending on oxygen pressure and type of cell lines. In summary, our findings suggest differences in metabolic adaptation to oxygen availability in vivo between primary and metastatic colon cancer cells.