ADAPTOR PROTEIN RUK/CIN85 IS INVOLVED IN THE GLUCOSE METABOLISM REPROGRAMMING IN BREAST CANCER CELLS

Aim. This study aimed to investigate the changes in glucose metabolism in mouse 4T1 breast adenocarcinoma cells with different levels of Ruk/CIN85 expression. Methods. We used 4T1 cells with stable overexpression (subline RukUp) or knockdown (subline RukDown) of Ruk/CIN85, as well as corresponding vector control sublines Mock and Scr. Cells were cultured in the complete RPMI-1640 medium under standard conditions. mRNA expression levels were estimated by RT2-PCR, enzymes activities were measured by spectrophotometric and/or fluorometric assays. Results. Analysis of mRNA expression of glucose metabolism-related genes in RukUp and RukDown cells revealed that glycolysis genes are preferentially overexpressed in RukUp cells, and downregulated in RukDown cells. Thus, RukUp cells were characterized by significantly overexpressed Slc2a1, Gck, Aldoa, and Ldha, while in RukDown cells these genes were either down regulated or not changed. However, the expression of TCA (tricarboxylic acid) cycle enzyme Mdh2 increased dramatically (by 7,8 times) in RukDown cells. In detail, we observed statistically significant changes in the activity of all studied enzymes in RukUp cells (increase by 1,5-1,9 times for glycolysis enzymes and G6PD, and decrease by 1,33-1,69 times for TCA enzymes). However, in RukDown cells we did not find any significant changes in glycolysis enzymes activities, but activities of mitochondrial IDH3 and MDH2 were elevated by 1,65 and 1,59 times, respectively. Conclusions. The results obtained indicate that adaptor protein Ruk/CIN85 is involved in the metabolic reprogramming during breast cancer progression. High level of Ruk/CIN85 expression is associated with potentiation of the Warburg effect.