VIPR1 and hepatocellular carcinoma: Moreover, the RNA-seq data indicated that VIP/VIPR1 signaling upregulates arginine anabolic enzymes expression and inhibits carbamoyl-phosphate synthetase 2, aspartate transcarbamylase, and dihydroorotase (CAD)-mediated pyrimidine biosynthesis, suggesting its involvement in metabolic regulation of HCC.