Abstract
Cancer is one of the most serious diseases facing humanity; accordingly, it is urgent to find a cure that is rarely harmful to the patient as much as possible. It has been approved that arginine deiminase (ADI) can hydrolyze the plasma arginine to citrulline. This hydrolysis activity and reduction in the amount of intercellular arginine suppress lipopolysaccharide-induced nitric oxide synthesis. On the other hand, arginine depletion arrests the cell cycle at the G1 phase; therefore, ADI has been considered a powerful anticancer agent. The current study aimed to investigate the lethal effects of ADI purified from the Lactobacillus plantarum p5 strain on murine mammary adenocarcinoma and Vero cell lines. Anti-proliferative activity of ADI against murine mammary adenocarcinoma) AMN3) cell line was evaluated after different incubation times (3, 6, 24, 48, and 72 h) of exposure to 1 µg/mL of ADI, compared to Vero (non-cancer cell line) transformed cell line with same conditions. The autophagy process in cancer cells was recognized after three hours of incubation with ADI which was clearly observed in the AMN3 cell line under an inverted microscope. The first stages of the programmed cell death (apoptosis) pathway were only observed in AMN3 cells after 24 h of incubation with ADI, and this process continued with the time until they reached the last stages of apoptosis after 72 h of incubation. The results of the current study showed that the AMN3 cell line was auxotrophic for arginine because it could not produce it in the presence of enzyme which had a robust activity to kill these cancer cells; however, Vero non-cancer cell line survived in the presence of ADI because it had the ability to produce arginine.