Hepatocellular carcinoma (HCC) is one of the most common causes of cancer death and is on the rise in the United States. Preventative strategies are highly important in reducing the incidence and death from HCC. HCC is a slow process that occurs in the setting of liver cell injury. Hepatocytes are triggered to replicate. Oxidative stress is induced resulting in oxidative damage to DNA. This setting gives way to mutation and other DNA aberrations that accumulate with time. Although many risk factors for HCC are known, the molecular pathogenesis of HCC is not well understood. In many chronic liver diseases that culminate in HCC, excess iron deposition is a common factor. Hepatic iron accumulation has been associated with genetic disorders including hereditary hemochromatosis, viral hepatitis including chronic hepatitis C virus, unusual dietary habits, and combinations of these conditions. Little is known about the effects of iron overload in the liver on regulatory pathways that could enable iron to serve as a cofactor in the process of hepatocarcinogenesis. We have generated a novel in vivo mouse model of chronic hepatic iron overload of liver using 3,5,5-trimethyl-hexanoyl ferrocene (TMHF) as an iron donor. Histological examination of livers from mice fed a TMHF diet for 9 weeks showed no signs of inflammation or necrosis. Hepatocytes underwent the expected physiological responses to iron in that ferritin levels were increased and transferrin receptor 1 levels were decreased. Iron overload, using TMHF as an iron donor, induced cyclin D1 expression, PCNA labeling index and hepatomegaly confirming similar findings in mice in which different iron donors were used to generate iron overload. Chronic iron loading also led to activation of 2-catenin and downregulation of hepatocyte membrane associated E-cadherin. We hypothesize that exposure of the liver to chronic insult of iron overload causes specific molecular and cellular changes that predispose the liver to progression to HCC. This hypothesis will be tested by different approaches in the four aims of this proposal which are: (1) to determine the effect of hepatic iron overload on the antioxidant defense system in liver, (2) to further evaluate the effects of iron overload on the cadherin-catenin complex and determine the effect of targeted alterations in E-cadherin on 2-catenin activation and cellular proliferation, (3) to determine whether hepatic iron overload can promote hepatocarcinogenesis, and (4) to evaluate the effects of chelation and antioxidant therapy alone and in combination on iron induced molecular and cellular changes in liver and on the ability of iron to function as a promoter in hepatocarcinogenesis. ? ? ?
| Moon, Mi Sun; Kang, Boo-Hyon; Krzeminski, Jacek et al. (2011) 3,5,5-trimethyl-hexanoyl-ferrocene diet protects mice from moderate transient acetaminophen-induced hepatotoxicity. Toxicol Sci 124:348-58 |
| Moon, Mi Sun; Richie, John P; Isom, Harriet C (2010) Iron potentiates acetaminophen-induced oxidative stress and mitochondrial dysfunction in cultured mouse hepatocytes. Toxicol Sci 118:119-27 |
