Figure 3.

Arginine reprogramming in glioma cells. In glioma cells, ASS1 expression was downregulated while CAT-1 and arginase were upregulated. The upregulated arginase is mainly arginase II located in the mitochondria. The use of ADI-PEG20 and HuArgI(CO)-PEG5000 to break down Circulating arginine results in a significant decrease in arginine concentration in the extracellular environment. Among the downstream metabolites of arginine, polyamines can promote tumor proliferation and metastasis, low concentrations of NO promote tumor proliferation and angiogenesis, and high concentrations of NO cause DNA damage. NO, nitric oxide; NOS, nitric oxide synthase; ARG, arginase; ODC, ornithine decarboxylase; OTC, ornithine transcarbamylase. ASS1,, argininosuccinate synthase; ASL, argininosuccinate lyase.;ADI-PEG20, pegylated arginine deaminase; HuArgI(CO)-PEG5000 ,Pegylated recombinant human arginase I.