Hydroxysafflor yellow A inhibits angiogenesis of hepatocellular carcinoma via blocking ERK/MAPK and NF-κB signaling pathway in H22 tumor-bearing mice

Abstract Hydroxysafflor yellow A (HSYA), a flavonoid derived and isolated from traditional Chinese medicine Carthamus tinctorius L., possesses anti-tumor activity. However, its effects on hepatocellular carcinoma (HCC) have not been investigated. The proliferation and metastasis of HCC are dependent on angiogenesis, which also strongly links with several signal transduction pathways associated with cell proliferation and apoptosis. This study aimed to explore the effect of HSYA on vasculogenesis and to determine its molecular mechanism by investigating the expression of ERK/MAPK (p-c-Raf, c-Raf, p-ERK1/2, ERK1/2) and NF-κB (p65, IκB and p-IκB) signaling pathway in H22 tumor-bearing mice. The results showed that HSYA could considerably suppress tumor growth by inhibiting secretion of angiogenesis factors (vascular endothelial growth factor A, basic fibroblast growth factor) and vascular endothelial growth factor receptor1. At the moleculcould block ERK1/2 phosphorylation and then restrain the activation of NF-κB and its nuclear translocation by down-regulating the expression of p65 in the nucleus, up-regulating p65 level in the cytoplasm, inhibiting IκB phosphorylation and cytoplasmic degradation of IκB-α. Finally, we demonstrate that HSYA could suppress mRNA expression levels of cell proliferation-related genes (cyclinD1, c-myc, c-Fos) compared with negative control group. And best of all, HSYA could improve spleen/thymus indexes, which was evaluated as the marker of protective effect on the immune system. Our findings support HSYA as a promising candidate for the prevention and treatment of HCC.