Recent studies have revealed that copper is an important cofactor for several angiogenic agents. We examined the antiangiogenic effect against hepatocellular carcinoma (HCC) of the copper chelator trientine, especially focusing on the relationship between copper and interleukin-8 (IL-8), a potent angiogenic factor produced by hepatoma cells. HuH-7 hepatoma cells were transplanted into nude mice and the growth of xenograft tumors was compared to and without administration of trientine. Using the resected tumor, microvessel density, apoptotic potential and proliferative activity were analyzed histologically and IL-8 mRNA was semiquantified by RT-PCR. In addition, HuH-7 cells were cultured in control medium, medium supplemented with copper, medium supplemented with trientine and medium supplemented with both copper and trientine. Human IL-8 levels were measured in the supernatants by ELISA. Using the extracts from cultured cells, IL-8 mRNA was semiquantified by RT-PCR. Trientine suppressed the growth of xenograft tumors significantly. Histologically, apoptotic potential was increased significantly and microvessel density, decreased. The production of IL-8 from the tumor was suppressed by trientine. In vitro, IL-8 production by HuH-7 cells in copper-containing medium was significantly greater than that in copper-free medium, and this effect was weakened when trientine was added. However, no significant change was apparent when trientine was added to the medium alone. In conclusion, the chelating effect of trientine prevented copper from functioning as a cofactor in angiogenesis, which resulted in reduced IL-8 production from HuH-7 cells.
Copyright 2002 Wiley-Liss, Inc.