Vynnytska-Myronovska B. Influence of arginine starvation on human cancer cell viability under monolayer and spheroid growth conditions

Object of the research: human cancer cell response to amino acid arginine depletion in vitro. The aim of the work: to compare the effect of arginine starvation on human malignant cells under monolayer and spheroid culture conditions and to investigate the anti-cancer properties of the novel combinational approach based on the co-application of arginine natural analogue canavanine and arginine-degrading enzyme arginase in vitro. Methods: approaches of cellular and molecular biology, biochemical, mathematical statistics. It was shown that arginine metabolic gene expression profile did not influence the level of sensitivity of cancer cells to arginine deprivation. It was revealed that all tested human cancer cell lines were auxotrophic for arginine. It was established that the reason of tumor cell death upon arginine starvation resided in caspase-dependent apoptosis induction. The analysis of human malignant cell sensitivity to arginine depletion in three-dimensional culture revealed that tumor spheroids were more resistant to arginine starvation, in comparison with appropriate monolayers. It was shown for the first time that both in monolayer and spheroid cultures low doses of canavanine applied in combination with arginine-degrading enzyme, arginase, were more toxic for human cancer cells, when compared with pseudonormal ones. We are first to show the radiosensitizing potential of the combination of arginase and canavanine. Area of use: cellular biology, molecular biology, radiology.