Mechanism of rhein inhibition of colorectal cancer through arginine metabolism based on protein chip / 药学学报

ABSTRACT

Rhein is an anthraquinone compound extracted from rhubarb, aloe vera, Polygonum multiflorum. In this study, we screened the potential targets of rhein through protein chip technology and investigated the underlying mechanism of its inhibition of colorectal cancer. Colony formation assay and scratch assay were used to examine the effect of rhein on the proliferation and migration abilities of HCT116 cell; KEGG and protein interaction analyses of rhein specific binding proteins by screening rhein binding proteins using protein chip; qRT-PCR and Western blot assays were used to determine the effect of rhein on the expression levels of BCL-2-associated X protein (BAX), B-cell lymphoma-2 (BCL-2) and argininosuccinate synthetase 1 (ASS1) in HCT116 cell. The antitumor effect of rhein was verified by azoxymethane combined with dextran sodium sulfate (AOM/DSS) induced colorectal cancer model. Experimental animal procedures were performed in accordance with animal welfare and the standards of the Laboratory Animal Ethics Committee of South China Agricultural University, with approval from the ethics committee. In vivo and in vitro results indicate that rhein specific binding proteins are mainly involved in amino acid anabolism, especially the arginine anabolic signaling pathway. Rhein inhibited the proliferation and migration of HCT116 cell in a concentration-dependent manner. Treated with rhein for 24 h significantly enhanced the expression of BAX and ASS1 in HCT116 cells, as well as the level of nitric oxide (NO) metabolism. In a mouse model of colorectal cancer, rhein significantly alleviated AOM/DSS induced weight loss and reduced fecal occult blood score. Meanwhile, rhein enhanced BAX and ASS1 expression in colon tumor tissue, as well as increased arginine and NO in serum. IHC and HE stain indicated that rhein alleviated Ki67 expression and macrophage infiltration in the colonic tissue of mice with AOM/DSS and delayed tumor formation. In conclusion, rhein can exert antitumor activity by regulating arginine and NO metabolism through ASS1.