EFFECT OF ADHESIVE LLC CELL PRETREATMENT BY OXAMATE ON THE SURVIVAL INDEXES AFTER TRANSITION TO DE-ADHESIVE GROWTH.

Background: The ability to metabolic reprogramming is a distinctive feature of metastatically active tumor cells. A classic example of metabolic reprogramming, characteristic of almost all malignant cells, is aerobic glycolysis. Therefore, inhibition of glycolysis in tumor cells is considered a promising strategy for antitumor therapy.

Aim: To generate Lewis lung carcinoma (LLC) cell subpopulation after pretreatment by a lactate dehydrogenase (LDH) inhibitor - oxamate in adhesive growth conditions, and then to study the metabolism of this subpopulation in the anchorage-independent growth conditions.

Materials and methods: LLC cells were cultured without oxamate or with 17 mM oxamate in the adhesive growth conditions with the following transition to the anchorage-independent growth conditions without oxamate. A distribution of LLC cells by cell cycle phases, apoptosis rate, levels of reactive oxygen species (ROS), E-cadherin, and vimentin were determined by flow cytometry. Glucose consumption and lactate production were determined by spectrophotometry.

Results: 48-h oxamate treatment in adhesive growth conditions resulted in a 30% decrease of the total number of LLC cells compared to the control. In 72 h after the transfer of both oxamate-treated and control cells into the anchorage-independent growth condition without oxamate, the number of viable cells pretreated with oxamate was reduced by 17% (p < 0.05) compared to the control cells. However, the distribution of cells by cell cycle phases did not differ. In cells pre-treated with oxamate, the rate of glucose consumption decreased by 20% (p < 0.05), ROS generation was reduced by 17%, vimentin expression decreased by 10% while the rate of lactate production was the same in oxamate-pretreated and control cells.

Conclusion: The cytostatic effect of oxamate demonstrated in adhesive growth conditions persisted for 72 h in the anchorage-independent growth conditions. The absence of differences in the cell cycle phase distribution and a decrease in the ROS generation may indicate the initial stage of overcoming the cytostatic effect of oxamate after 72 h of culturing LLC cells in anchorage- independent growth conditions.