The effects of angelica sinensis polysaccharide on tumor growth and iron metabolism by regulating hepcidin in tumor-bearing mice

Abstract

Background/Aims: Iron plays a fundamental role in cell biology and its concentration must be precisely regulated. It is well documented that excess iron burden contributes to the occurrence and progression of cancer. Hepcidin secreted by liver plays an essential role in orchestrating iron metabolism. In the present study, we aimed to investigate the ability of angelica sinensis polysaccharide (ASP) to decrease iron burden in tumor-bearing mice and the mechanism of ASP regulation hepcidin expression. Methods: Western blot, RT-PCR, immunohistochemistry (IHC), and enzyme-linked immunosorbent assay (ELISA) were used to detect the regulation of hepcidin and related cytokines by ASP. The role of ASP in tumor proliferation was investigated using in vivo assays. Iron depositions and iron concentrations in organs were determined by hematoxylin-eosin (H&E) staining and atomic absorption spectrophotometer. Results: We found that ASP could inhibit tumor growth in mice xenografted with 4T1 and H22 cancer cells. In vivo experiments also showed that ASP could potently regulate hepcidin expression in liver and serum and decrease iron burden in liver, spleen and grafted tumors in mouse model. Treatment with ASP in hepatic cell lines reproduced comparable results in decreasing hepcidin as in mouse liver. Furthermore, we found that ASP markedly suppressed the expression of interleukin-6 (IL-6), JAK2, p-STAT3, and p-SMAD1/5/8 in liver, suggesting that JAK/STAT and BMP-SMAD pathways were involved in the regulation of hepcidin expression by ASP. We also found down-regulation of iron-related cytokines in ASP treated mice. Conclusion: The present study provides new evidence that ASP decreases hepcidin expression, which can reduce iron burden and inhibit tumor proliferation. These findings might aid ASP developed as a potential candidate for cancer treatment in patients with iron overload.