Hepatocellular carcinoma caused by iron overload: a possible mechanism of direct hepatocarcinogenicity

Iron, Oxidative Stress, and Metabolic Dysfunction-Associated Steatotic Liver Disease

Excess free iron is a substrate for the formation of reactive oxygen species (ROS), thereby augmenting oxidative stress. Oxidative stress is a well-established cause of organ damage in the liver, the main site of iron storage. Ferroptosis, an iron-dependent mechanism of regulated cell death, has recently been gaining attention in the development of organ damage and the progression of liver disease. We therefore summarize the main mechanisms of iron metabolism, its close connection to oxidative stress and ferroptosis, and its particular relevance to disease mechanisms in metabolic-dysfunction-associated fatty liver disease and potential targets for therapy from a clinical perspective.

Hepatocellular carcinoma with lung metastasis showing hemochromatosis in an Egyptian fruit bat (Rousettus aegyptiacus)

After an Egyptian fruit bat (Rousettus aegyptiacus) in a zoo became emaciated and died, a necropsy revealed multiple nodules on the liver and lung surfaces. Microscopy revealed that the liver nodules consisted of neoplastic hepatocytes and showed metastasis in the lung lobes. Most of the neoplastic cells in the liver and lung showed positive labeling for HepPar-1, cytokeratin 19, glypican-3, and Ki-67. Hepatocellular degeneration and necrosis were diffuse in the liver parenchyma. Berlin blue staining revealed large amounts of iron in normal and neoplastic cells. Based on these pieces of evidence, this case was diagnosed as hepatocellular carcinoma with hemochromatosis. This is believed to be the first report of hepatocellular carcinoma in an Egyptian fruit bat that has been immunophenotypically examined in detail by pathological examination.

Transferrin Receptor is Associated with Sensitivity to Ferroptosis Inducers in Hepatocellular Carcinoma

PURPOSE

Transferrin receptor (TFR), a membrane protein that has a critical role in the transport of iron into cells, is known to be a ferroptosis-related marker. Although TFR is reported to be abundantly expressed in tumor cells, its relationship with ferroptosis inducers in hepatocellular carcinoma (HCC) remains unclear.

METHODS

The authors performed immunohistochemical staining of TFR and divided 350 HCC patients into two groups according to its expression. They analyzed the association between TFR expression and prognosis or clinicopathologic factors. In addition, the regulation of malignant activity and its effect on the efficacy of ferroptosis inducers were investigated in vitro.

RESULTS

For this study, 350 patients were divided into TFR-positive (n =180, 51.4%) and TFR-negative (n = 170, 48.6%) groups. The TFR-positive group had more hepatitis B surface antigen (HBs-Ag) (p = 0.0230), higher α-fetoprotein (AFP) levels (p = 0.0023), higher des-gamma-carboxyprothrombin (DCP) levels (p = 0.0327), a larger tumor size (p = 0.0090), greater proportions of Barcelona Clinic Liver Cancer (BCLC) stage B or C (p = 0.0005), poor differentiation (p < 0.0001), and microscopic intrahepatic metastasis (p = 0.0066). In the multivariate analyses, TFR expression was an independent prognostic factor in disease-free survival (p = 0.0315). In vitro, TFRC knockdown decreased cell motility. In addition, TFRC knockdown abolished artesunate (AS)-, lenvatinib-, and sorafenib-induced ferroptosis in HCC cell lines. The study demonstrated that simultaneous treatment of AS with multi-kinase inhibitor augmented the ferroptosis-inducing effects of AS in HCC cell lines.

CONCLUSION

TFR expression is a poor prognostic factor in HCC, but its expression increases sensitivity to ferroptosis-inducing agents.

Iron as a therapeutic target in chronic liver disease

It was clearly realized more than 50 years ago that iron deposition in the liver may be a critical factor in the development and progression of liver disease. The recent clarification of ferroptosis as a specific form of regulated hepatocyte death different from apoptosis and the description of ferritinophagy as a specific variation of autophagy prompted detailed investigations on the association of iron and the liver. In this review, we will present a brief discussion of iron absorption and handling by the liver with emphasis on the role of liver macrophages and the significance of the iron regulators hepcidin, transferrin, and ferritin in iron homeostasis. The regulation of ferroptosis by endogenous and exogenous mod-ulators will be examined. Furthermore, the involvement of iron and ferroptosis in various liver diseases including alcoholic and non-alcoholic liver disease, chronic hepatitis B and C, liver fibrosis, and hepatocellular carcinoma (HCC) will be analyzed. Finally, experimental and clinical results following interventions to reduce iron deposition and the promising manipulation of ferroptosis will be presented. Most liver diseases will be benefited by ferroptosis inhibition using exogenous inhibitors with the notable exception of HCC, where induction of ferroptosis is the desired effect. Current evidence mostly stems from in vitro and in vivo experimental studies and the need for well-designed future clinical trials is warranted.

Iron and liver cancer: an inseparable connection

Iron is an essential element for all organisms. Iron-containing proteins play critical roles in cellular functions. The biological importance of iron is largely attributable to its chemical properties as a transitional metal. However, an excess of 'free' reactive iron damages the macromolecular components of cells and cellular DNA through the production of harmful free radicals. On the contrary, most of the body's excess iron is stored in the liver. Not only hereditary haemochromatosis but also some liver diseases with mild-to-moderate hepatic iron accumulation, such as chronic hepatitis C, alcoholic liver disease and nonalcoholic steatohepatitis, are associated with a high risk for liver cancer development. These findings have attracted attention to the causative and promotive roles of iron in the development of liver cancer. In the last decade, accumulating evidence regarding molecules regulating iron metabolism or iron-related cell death programmes such as ferroptosis has shed light on the relationship between hepatic iron accumulation and hepatocarcinogenesis. In this review, we briefly present the current molecular understanding of iron regulation in the liver. Next, we describe the mechanisms underlying dysregulated iron metabolism depending on the aetiology of liver diseases. Finally, we discuss the causative and promotive roles of iron in cancer development.

Iron-Induced Hepatocarcinogenesis—Preventive Effects of Nutrients

The liver is a primary organ that stores body iron, and plays a central role in the regulation of iron homeostasis. Hepatic iron overload (HIO) is a prevalent feature among patients with chronic liver diseases (CLDs), including alcoholic/nonalcoholic liver diseases and hepatitis C. HIO is suggested to promote the progression toward hepatocellular carcinoma because of the pro-oxidant nature of iron. Iron metabolism is tightly regulated by various factors, such as hepcidin and ferroportin, in healthy individuals to protect the liver from such deteriorative effects. However, their intrinsic expressions or functions are frequently compromised in patients with HIO. Thus, various nutrients have been reported to regulate hepatic iron metabolism and protect the liver from iron-induced damage. These nutrients are beneficial in HIO-associated CLD treatment and eventually prevent iron-mediated hepatocarcinogenesis. This mini-review aimed to discuss the mechanisms and hepatocarcinogenic risk of HIO in patients with CLDs. Moreover, nutrients that hold the potential to prevent iron-induced hepatocarcinogenesis are summarized.

Metal Ion-Based Supramolecular Self-Assembly for Cancer Theranostics

Metal-ion-based self-assembly supramolecular theranostics exhibit excellent performance in biomedical applications owing to their potential superiorities for simultaneous precise diagnosis, targeted drug delivery, and monitoring the response to therapy in real-time. Specially, the rational designed systems could achieve specific in vivo self-assembly through complexation or ionic interaction to improve tissue-specific accumulation, penetration, and cell internalization, thereby reducing toxicities of drugs in diagnostics and therapy. Furthermore, such imaging traceable nanosystems could provide real-timely information of drug accumulation and therapeutic effects in a non-invasive and safe manner. Herein, the article highlights the recent prominent applications based on the metal ions self-assembly in cancer treatment. This strategy may open up new research directions to develop novel drug delivery systems for cancer theranostics.

Oxidative Stress and Redox Signaling in the Pathophysiology of Liver Diseases

The increased production of derivatives of molecular oxygen and nitrogen in the form of reactive oxygen species (ROS) and reactive nitrogen species (RNS) lead to molecular damage called oxidative stress. Under normal physiological conditions, the ROS generation is tightly regulated in different cells and cellular compartments. Any disturbance in the balance between the cellular generation of ROS and antioxidant balance leads to oxidative stress. In this article, we discuss the sources of ROS (endogenous and exogenous) and antioxidant mechanisms. We also focus on the pathophysiological significance of oxidative stress in various cell types of the liver. Oxidative stress is implicated in the development and progression of various liver diseases. We narrate the master regulators of ROS-mediated signaling and their contribution to liver diseases. Nonalcoholic fatty liver diseases (NAFLD) are influenced by a "multiple parallel-hit model" in which oxidative stress plays a central role. We highlight the recent findings on the role of oxidative stress in the spectrum of NAFLD, including fibrosis and liver cancer. Finally, we provide a brief overview of oxidative stress biomarkers and their therapeutic applications in various liver-related disorders. Overall, the article sheds light on the significance of oxidative stress in the pathophysiology of the liver. © 2022 American Physiological Society. Compr Physiol 12:3167-3192, 2022.

Hemojuvelin deficiency promotes liver mitochondrial dysfunction and predisposes mice to hepatocellular carcinoma

Hemojuvelin (HJV) enhances signaling to the iron hormone hepcidin and its deficiency causes iron overload, a risk factor for hepatocellular carcinoma (HCC). We utilized Hjv^−/− mice to dissect mechanisms for hepatocarcinogenesis. We show that suboptimal treatment with diethylnitrosamine (DEN) triggers HCC only in Hjv^−/− but not wt mice. Liver proteomics data were obtained by mass spectrometry. Hierarchical clustering analysis revealed that Hjv deficiency and DEN elicit similar liver proteomic responses, including induction of mitochondrial proteins. Dietary iron overload of wt mice does not recapitulate the liver proteomic phenotype of Hjv^−/− animals, which is only partially corrected by iron depletion. Consistent with these data, primary Hjv^−/− hepatocytes exhibit mitochondrial hyperactivity, while aged Hjv^−/− mice develop spontaneous HCC. Moreover, low expression of HJV or hepcidin (HAMP) mRNAs predicts poor prognosis in HCC patients. We conclude that Hjv has a hepatoprotective function and its deficiency in mice promotes mitochondrial dysfunction and hepatocarcinogenesis.

Hemojuvelin (HJV), a BMP co-receptor promoting hepcidin expression in the liver, has a hepatoprotective function and its deficiency in mice triggers mitochondrial dysfunction and hepatocarcinogenesis.

Lifestyle and Hepatocellular Carcinoma What Is the Evidence and Prevention Recommendations

Simple Summary

The increasing public health burden of Hepatocellular carcinoma (HCC) emphasizes the importance of defining important modifiable risk factors. In the following review, we will discuss the evidence for the relation of major lifestyle risk factors, mostly from large population-based studies. Generally, it is has been shown that healthy lifestyle habits, including minimizing obesity, eating a healthy diet, avoidance of smoking and alcohol, and increasing physical activity, have the potential to prevent HCC. Dietary composition is important beyond obesity. Consumption of n-3 polyunsaturated fatty acids, as well as fish and poultry, vegetables and fiber, are inversely associated with HCC, while red meat, saturated fat, cholesterol and sugar are related to increased risk. Data from multiple studies clearly show a beneficial effect for physical activity in reducing the risk of HCC. Smoking and alcohol can lead to liver fibrosis and liver cancer and jointly lead to an even greater risk.

Abstract

The increasing burden of hepatocellular carcinoma (HCC) emphasizes the unmet need for primary prevention. Lifestyle measures appear to be important modifiable risk factors for HCC regardless of its etiology. Lifestyle patterns, as a whole and each component separately, are related to HCC risk. Dietary composition is important beyond obesity. Consumption of n-3 polyunsaturated fatty acids, as well as fish and poultry, are inversely associated with HCC, while red meat, saturated fat, and cholesterol are related to increased risk. Sugar consumption is associated with HCC risk, while fiber and vegetable intake is protective. Data from multiple studies clearly show a beneficial effect for physical activity in reducing the risk of HCC. However, the duration, mode and intensity of physical activity needed are yet to be determined. There is evidence that smoking can lead to liver fibrosis and liver cancer and has a synergistic effect with alcohol drinking. On the other hand, an excessive amount of alcohol by itself has been associated with increased risk of HCC directly (carcinogenic effect) or indirectly (liver fibrosis and cirrhosis progression. Large-scale intervention studies testing the effect of comprehensive lifestyle interventions on HCC prevention among diverse cohorts of liver disease patients are greatly warranted.

Repurposing ICG enables MR/PA imaging signal amplification and iron depletion for iron-overload disorders

Precise and noninvasive theranostic methods to quantify and deplete focal iron are of crucial importance for iron-overload disorders. Here, we developed an indocyanine green (ICG)–based imaging platform to reveal Fe³⁺ in vitro and in vivo. The high sensitivity and specificity of ICG-Fe interaction facilitated MR images with a marked correlation between T₁ signal intensity ratio (T₁SIR) changes and Fe³⁺ concentration in rodent models and humans. On the basis of these findings, a rational design for coordination-driven self-assembly ICG-Lecithin (ICG/Leci) was proposed to determine Fe³⁺. The enhancement of photoacoustic signal at 890 nm with increasing Fe³⁺ concentration showed an over 600% higher linear slope than that of T₁SIR changes in animal models. ICG/Leci also promoted a 100% increase in iron depletion in the liver compared with deferoxamine. The high MR sensitivity and superior photoacoustic contrast, combined with enhanced iron depletion, demonstrate that ICG/Leci is a promising theranostic agent for simultaneous detection and treatment of iron-overload disorders.

Iron at the Interface of Hepatocellular Carcinoma

Cancer incidence and mortality are rapidly growing, with liver cancer being the sixth most diagnosed cancer worldwide and the third leading cause of cancer death in 2020. A number of risk factors have been identified that trigger the progression to hepatocellular carcinoma. In this review, we focus on iron as a potential risk factor for liver carcinogenesis. Molecules involved in the regulation of iron metabolism are often upregulated in cancer cells, in order to provide a supply of this essential trace element for all stages of tumor development, survival, proliferation, and metastasis. Thus, cellular and systemic iron levels must be tightly regulated to prevent or delay liver cancer progression. Disorders associated with dysregulated iron metabolism are characterized with increased susceptibility to hepatocellular carcinoma. This review discusses the association of iron with metabolic disorders such as hereditary hemochromatosis, non-alcoholic fatty liver disease, obesity, and type 2 diabetes, in the background of hepatocellular carcinoma.

Trace Elements Status and Metallothioneins DNA Methylation Influence Human Hepatocellular Carcinoma Survival Rate

Background

Mechanisms underlying hepatocellular carcinoma (HCC) development are largely unknown. The role of trace elements and proteins regulating metal ions homeostasis, i.e. metallothioneins (MTs), recently gained an increased interest. Object of the study was to investigate the role of promoter DNA methylation in MTs transcriptional regulation and the possible prognostic significance of serum trace elements in HCC.

Methods

Forty-nine HCC patients were enrolled and clinically characterized. Cu, Se, and Zn contents were measured by Inductively Coupled Plasma Mass Spectrometry in the serum and, for a subset of 27 patients, in HCC and homologous non-neoplastic liver (N) tissues. MT1G and MT1H gene expression in hepatic tissues was assessed by Real-Time RT-PCR and the specific promoter DNA methylation by Bisulfite-Amplicon Sequencing.

Results

Patients with Cu serum concentration above the 80^th percentile had a significantly decreased survival rate (P < 0.001) with a marked increased hazard ratio for mortality (HR 6.88 with 95% CI 2.60-18.23, P < 0.001). Se and Zn levels were significantly lower in HCC as compared to N tissues (P < 0.0001). MT1G and MT1H gene expression was significantly down-regulated in HCC as compared to N tissues (P < 0.05). MTs promoter was hypermethylated in 9 out of the 19 HCC tissues showing MTs down-regulation and methylation levels of three specific CpGs paralleled to an increased mortality rate among the 23 patients analyzed (P = 0.015).

Conclusions

MT1G and MT1H act as potential tumor suppressor genes regulated through promoter DNA methylation and, together with serum Cu concentrations, be related to survival rate in HCC.

Association between IL28B Polymorphisms and Outcomes of Hepatitis B Virus Infection: A meta-analysis

BACKGROUND

Interleukin (IL) 28B polymorphisms encoding pro-inflammatory and anti-inflammatory cytokines trigger diverse clinical outcome of hepatitis virus infection. However, there is controversy concerning the association of IL28B polymorphisms with the outcome of hepatitis B virus (HBV) infection, with several studies obtaining inconsistent results. We performed a meta-analysis to evaluate the role of 3 single nucleotide polymorphisms (SNPs) rs12979860, rs12980275 and rs8099917 in the progression of HBV infection, overall and by ethnicity.

METHODS

Searched PubMed, Embase and Wiley Online Library electronic databases using 'interleukin 28B', 'IL 28B', 'IL 28B polymorphism', 'hepatitis B virus', 'HBV', and performed meta- analysis for rs12979860, rs12980275 and rs8099917 in Asian and Caucasian populations under the dominant recessive and allele model.

RESULTS

Eighteen studies were found in total and used for this meta-analysis, including 5587 cases and 4295 controls. The IL28B polymorphism rs12979860 had no association with HBV persistence (CC vs CT + TT: OR = 0.86, 95% CI = 0.76-1.00; TT vs CT + CC: OR = 1.14, 95% CI = 0.76-1.70; T vs C: OR = 1.03, 95% CI = 0.94-1.13). Similarly, neither rs12980275 nor rs8099917 had associations with HBV persistence (rs12980275 in AA vs AG + AA: OR = 1.15, 95% CI = 0.96-1.38; rs8099917 in TT vs GT + GG: OR = 1.15, 95% CI = 0.96-1.39). There was also no significant association of IL28B polymorphisms with persistent HBV infection in Asians or Chinese. There was no evidence of an association of rs12979860 with the HBV-related hepatocellular carcinoma susceptibility (T vs C: OR = 1.53, 95% CI = 0.96-2.43).

CONCLUSION

IL28B polymorphisms had no association with the outcome of HBV infection overall, nor in the Asians and the Chinese. These 3 SNPs might not be relevant to the development of HBV infection.

Hepatic copper and other trace mineral concentrations in dogs with hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is the most common primary liver tumor in dogs. Abnormalities in hepatic copper, iron, zinc, and selenium concentrations increase risk for HCC development in other species, but trace mineral concentrations have not been evaluated in dogs with HCC.

Objectives

To investigate hepatic trace mineral concentrations in dogs with HCC.

Animals

Archived liver specimens from 85 dogs with HCC and 85 control dogs.

Methods

Retrospective case‐control study. A histopathology database was searched to identify dogs with HCC (test population) and an age‐matched control population. Demographic information was retrieved, and H&E and rhodanine stained slides were reviewed for all cases. Copper, iron, zinc, and selenium concentrations were determined in noncancerous liver tissues (test and control population) and in HCC tissues (test population) using inductively coupled plasma mass spectrometry.

Results

Hepatic copper concentrations (non‐neoplastic hepatic tissue) were greater in test population dogs (median, IQR; 294.9 μg/g, 233.5‐475.9 μg/g) than in control dogs (202.8 μg/g, 135.0‐295.3 μg/g; P < .001). Hepatic zinc concentrations in test (132.1 μg/g,108.6‐163.2 μg/g) and control dogs (151.5 μg/g, 117.1‐184.5 μg/g) also were different (P = .03). Within test population dogs, all trace mineral concentrations were decreased in the HCC tissue as compared to the non‐neoplastic hepatic tissue (all P < .001).

Conclusions and Clinical Importance

Hepatic copper accumulation and other abnormalities in hepatic trace mineral concentrations could be involved in the pathogenesis of HCC in some dogs.

Effects of a moderate iron overload and its interaction with yacon flour, and/or phytate, in the diet on liver antioxidant enzymes and hepatocyte apoptosis in rats

The effect of moderate Fe overload in the diet and its interaction with phytate, and/or yacon flour (YF), recognized as an inhibitor, and facilitator, of Fe absorption, respectively, was evaluated in healthy rats. For this purpose the following parameters were analyzed: (1) apparent iron (Fe), copper (Cu) and zinc (Zn) absorption; (2) blood Fe; (3) blood lipids (cholesterol, tryacylglicerol); (4) blood AST and ALT; (5) liver histology (histopathology, hemosiderin depots, apoptosis index; (6) liver fatty acid incorporation; (7) liver antioxidant enzyme activity. Moderate Fe overload may cause change in some liver markers (hemosiderin depots, apoptosis index and GPx) and blood lipids (total cholesterol and VLDL) and the interaction with yacon flour, and phytate, in the Fe overloaded diets may exert a protective effect on these alterations.

Alcohol and hepatocellular carcinoma

Background

Alcohol is classified as a Group 1 carcinogen by the International Agency for Research on Cancer because it induces hepatocellular carcinoma (among other cancers) in humans. An excessive alcohol intake may result in fatty liver, acute/chronic hepatitis, and cirrhosis and eventually lead to hepatocellular carcinoma. It has been reported that alcohol abuse increases the relative risk of hepatocellular carcinoma by 3- to 10-fold.

Aim and Methods

To clarify the known mechanisms of alcohol-related carcinogenesis, we searched Pubmed using the terms alcohol and immune mechanism, alcohol and cancer, and immune mechanism and cancer and summarized the articles as a qualitative review.

Results

From a clinical perspective, it is well known that alcohol interacts with other factors, such as smoking, viral hepatitis, and diabetes, leading to an increased risk of hepatocellular carcinoma. There are several possible mechanisms through which alcohol may induce liver carcinogenicity, including the mutagenic effects of acetaldehyde and the production of ROS due to the excessive hepatic deposition of iron. Furthermore, it has been reported that alcohol accelerates hepatitis C virus-induced liver tumorigenesis through TLR4 signaling. Despite intense investigations to elucidate the mechanisms, they remain poorly understood.

Conclusion

This review summarizes the recent findings of clinical and pathological studies that have investigated the carcinogenic effects of alcohol in the liver.

Ferritin level prospectively predicts hepatocarcinogenesis in patients with chronic hepatitis B virus infection

Previous studies have detected a higher level of ferritin in patients with hepatocellular carcinoma (HCC), but a potential causal association between serum ferritin level and hepatocarcinogenesis remains to be clarified. Using a well-established prospective cohort and longitudinally collected serial blood samples, the association between baseline ferritin levels and HCC risk were evaluated in 1,152 patients infected with hepatitis B virus (HBV), a major risk factor for HCC. The association was assessed by Cox proportional hazards regression model using univariate and multivariate analyses and longitudinal analysis. It was demonstrated that HBV patients who developed HCC had a significantly higher baseline ferritin level than those who remained cancer-free (188.00 vs. 108.00 ng/ml, P<0.0001). The patients with a high ferritin level (≥200 ng/ml) had 2.43-fold increased risk of HCC compared to those with lower ferritin levels [hazard ratio (HR), 2.43; 95% confidence interval, 1.63–3.63]. A significant trend of increasing HRs along with elevated ferritin levels was observed (P for trend <0.0001). The association was still significant after multivariate adjustment. Incorporating ferritin into the α-fetoprotein (AFP) model significantly improved the performance of HCC prediction (the area under the curve from 0.74 to 0.77, P=0.003). Longitudinal analysis showed that the average ferritin level in HBV patients who developed HCC was persistently higher than in those who were cancer-free during follow-up. HCC risk reached a peak at approximately the fifth year after baseline ferritin detection. Moreover, stratified analyses showed that the association was noted in both males and females, and was prominent in patients with a low AFP value. In short, serum ferritin level could independently predict the risk of HBV-related HCC and may have a complementary role in AFP-based HCC diagnosis. Future studies are warranted to validate these findings and test its clinical applicability in HCC prevention and management.

Hepatic iron overload in the portal tract predicts poor survival in hepatocellular carcinoma after curative resection

BACKGROUND & AIMS

Hepatic iron overload is associated with liver injury and hepatocarcinogenesis; however, it has not been evaluated in patients with hepatocellular carcinoma (HCC) in Asia. The aim of this study was to clarify the degree and distribution of intrahepatic iron deposition, and their effects on the survival of HCC patients.

METHODS

Intrahepatic iron deposition was examined using non-tumorous liver tissues from 204 HCC patients after curative resection, and they were scored by 2 semi-quantitative methods: simplified Scheuer's and modified Deugnier's methods. For the Scheuer's method, iron deposition in hepatocytes and Kupffer cells was separately evaluated, while for the modified Deugnier's method, hepatocyte iron score (HIS), sinusoidal iron score (SIS) and portal iron score (PIS) were systematically evaluated, and the corrected total iron score (cTIS) was calculated by multiplying the sum (TIS) of the HIS, SIS, and PIS by the coefficient.

RESULTS

The overall prevalence of hepatic iron was 40.7% with the simplified Scheuer's method and 45.1% with the modified Deugnier's method with a mean cTIS score of 2.46. During a median follow-up of 67 months, the cTIS was not associated with overall survival. However, a positive PIS was significantly associated with a lower 5-year overall survival rate (50.0%) compared with a negative PIS (73.7%, P = .006). In the multivariate analysis, a positive PIS was an independent factor for overall mortality (hazard ratio, 2.310; 95% confidence interval, 1.181-4.517).

CONCLUSIONS

Intrahepatic iron deposition was common, and iron overload in the portal tract indicated poor survival in curatively resected HCC patients.

A novel low molecular weight Enteromorpha polysaccharide-iron (III) complex and its effect on rats with iron deficiency anemia (IDA)

Iron deficiency anemia (IDA) is a common nutritional disease that affects normal erythropoiesis. Traditional iron supplements usually cause gastrointestinal irritation. In this study, a novel low-molecular-weight polysaccharide from Enteromorpha prolifera (LPE) was prepared by oxidation degradation, and LPE-iron (III) complex was synthesized and characterized. The molecular weight of LPE-iron (III) complex was 21.25kDa, and iron content was 25%. The therapeutic effects of LPE-iron (III) complex on IDA were investigated in rats. The hematological indices and organ coefficients of the rats were analyzed. Results showed a dose-dependent relationship, and a prior intragastric administration of LPE-iron (III) complex (2mg Fe/kg body weight) exhibited considerable effect when compared with the positive control. Therefore, LPE-iron (III) complex could be exploited as a new iron fortifier.

Roles of p53 in extrinsic factor-induced liver carcinogenesis

Liver cancer remains one of the most common human cancers with a high mortality rate. Therapies for hepatocellular carcinoma (HCC) remain ineffective, due to the heterogeneity of HCC with regard to both the etiology and mutation spectrum, as well as its chemotherapy resistant nature; thus surgical resection and liver transplantation remain the gold standard of patient care. The most common etiologies of HCC are extrinsic factors. Humans have multiple defense mechanisms against extrinsic factor-induced carcinogenesis, of which tumor suppressors play crucial roles in preventing normal cells from becoming cancerous. The tumor suppressor p53 is one of the most frequently mutated genes in liver cancer. p53 regulates expression of genes involved in cell cycle progression, cell death, and cellular metabolism to avert tumor development due to carcinogens. This review article mainly summarizes extrinsic factors that induce liver cancer and potentially have etiological association with p53, including aflatoxin B1, vinyl chloride, non-alcoholic fatty liver disease, iron overload, and infection of hepatitis viruses.

Roles of Copper in Hepatocarcinogenesis via the Activation of Hypoxia-Inducible Factor-1α

Hypoxia-inducible factor-1α (HIF-1α) is involved in the pathogenesis of hepatocellular carcinoma (HCC). However, the roles of trace elements in the activation of HIF-1α during hepatocarcinogenesis have been unclear. We investigated whether copper (Cu) and zinc (Zn) participated in the activation of HIF-1α in the process of hepatocarcinogenesis or not. Nine patients with chronic hepatitis (CH), five with liver cirrhosis (LC), 12 with HCC, and nine normal healthy controls were enrolled in this study. Their serum HIF-1α, Cu, and Zn levels were determined in the enrolled patients. Hepatic HIF-1α expression was evaluated, using an immunohistochemical procedure. The HCC patients had significantly higher serum HIF-1α levels than the CH patients (6.47 ± 1.57 vs. 5.09 ± 1.22 ng/ml, p = 0.0344). The serum Cu level in the HCC patients was also significantly higher than those in the CH and LC patients (137 ± 24 vs. 107 ± 15 μg/dl, 114 ± 24 μg/dl). Interestingly, a positive correlation was observed between serum HIF-1α and Cu levels in the enrolled patients (r = 0.425, p = 0.0137). In contrast, no significant differences in serum Zn levels were present between the HCC patients and the CH or LC patients. The serum HIF-1α was not positively correlated with the serum Zn level in the enrolled patients, either. Immunohistochemical analysis revealed that two of the five HCC patients had HIF-1α expression in the tumor tissues, whereas none of CH and LC had hepatic HIF-1α expression in the liver tissues. These data suggest that the activation of HIF-1α derived from a Cu accumulation in the liver may cause hepatocarcinogenesis.

The role of genetic factors in patients with hepatocellular carcinoma and iron overload - a prospective series of 234 patients

BACKGROUND & AIMS

Iron overload (IO) in HFE-related hereditary haemochromatosis is associated with increased risk of liver cancer. This study aimed to investigate the role of other genes involved in hereditary IO among patients with hepatocellular carcinoma (HCC).

METHODS

Patients with HCC diagnosed in our institution were included in this prospective study. Those with ferritin levels ≥300 μg/L (males) or ≥200 μg/L (females) and/or transferrin saturation ≥50% (males) or ≥45% (females) had liver iron concentration (LIC) evaluated by MRI. HFE C282Y and H63D mutations were screened. Genetic analyses of genes involved in hereditary IO (HFE, HJV/HFE2, HAMP, TFR2, SLC40A1, GNPAT) were performed in patients with increased LIC.

RESULTS

A total of 234 patients were included; 215 (92%) had common acquired risk factors of HCC (mainly alcoholism or chronic viral hepatitis). 119 patients had abnormal iron parameters. Twelve (5.1%) were C282Y homozygotes, three were compound C282Y/H63D heterozygotes. LIC was measured by MRI in 100 patients. Thirteen patients with a LIC>70 μmol/g were enrolled in further genetic analyses: two unrelated patients bore the HAMP:c.-153C>T mutation at the heterozygous state, which is associated with increased risk of IO and severe haemochromatosis. Specific haplotypes of SLC40A1 were also studied.

CONCLUSIONS

Additional genetic risk factors of IO were found in 18 patients (7.7%) among a large series of 234 HCC patients. Screening for IO and the associated at-risk genotypes in patients who have developed HCC, is useful for both determining etiologic diagnosis and enabling family screening and possibly primary prevention in relatives.

Deferasirox, an oral iron chelator, prevents hepatocarcinogenesis and adverse effects of sorafenib

Although sorafenib is expected to have a chemopreventive effect on hepatocellular carcinoma (HCC) recurrence, there are limitations to its use because of adverse effects, including effects on liver function. We have reported that the iron chelator, deferoxamine can prevent liver fibrosis and preneoplastic lesions. We investigated the influence of administering a new oral iron chelator, deferasirox (DFX), on the effects of sorafenib. We used the choline-deficient l-amino acid-defined (CDAA) diet-induced rat liver fibrosis and HCC model. We divided rats into four groups: CDAA diet only (control group), CDAA diet with sorafenib (sorafenib group), CDAA diet with DFX (DFX group), and CDAA diet with DFX and sorafenib (DFX + sorafenib group). Liver fibrosis and development of preneoplastic lesions were assessed. In addition, we assessed adverse effects such as changes in body and liver weight, skin damage (eruption, dryness, and hair loss), which is defined as hand-foot skin syndrome, in the sorafenib and DFX + sorafenib groups. The combination of DFX + sorafenib markedly prevented liver fibrosis and preneoplastic lesions better than the other treatments. Furthermore, the combination therapy significantly decreased adverse effects compared with the sorafenib group. In conclusion, the combination therapy with DFX and sorafenib may be a useful adjuvant therapy to prevent recurrence after curative treatment of HCC.

Ameliorating role of rutin on oxidative stress induced by iron overload in hepatic tissue of rats

Iron is an essential element that participates in several metabolic activities of cells; however, excess iron is a major cause of iron-induced oxidative stress and several human diseases. Natural flavonoids, as rutin, are well-known antioxidants and could be efficient protective agents. Therefore, the present study was undertaken to evaluate the protective influence of rutin supplementation to improve rat antioxidant systems against IOL-induced hepatic oxidative stress. Sixty male albino rats were randomly divided to three equal groups. The first group, the control, the second group, iron overload group, the third group was used as iron overload+rutin group. Rats received six doses of ferric hydroxide polymaltose (100 mg kg(-1) b.wt.) as one dose every two days, by intraperitoneal injections (IP) and administrated rutin (50 mg kg(-1) b.wt.) as one daily oral dose until the sacrificed day. Blood samples for serum separation and liver tissue specimens were collected three times, after three, four and five weeks from the onset of the experiment. Serum iron profiles total iron, Total Iron Binding Capacity (TIBC), Unsaturated Iron Binding Capacity (UIBC), transferrin (Tf) and Transferrin Saturation% (TS%)}, ferritin, albumin, total Protein, total cholesterol, triacylglycerols levels and aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities were determined. Moreover, total iron in the liver, L-malondialdehyde (L-MDA), glutathione (GSH), Nitric Oxide (NO) and Total Nucleic Acid (TNA) levels and glutathione peroxidase (GPx), catalase (CAT) and superoxide dismutase (SOD) activities were also determined. The obtained results revealed that, iron overload (IOL) resulted in significant increase in serum iron, TIBC, Tf, TS% and ferritin levels and AST and ALT activities and also increased liver iron, L-MDA and NO levels. Meanwhile, it decreased serum UIBC, total cholesterol, triacylglycerols, albumin, total protein and liver GSH, TNA levels and Gpx, CAT and SOD activities when compared with the control group. Rutin administration to iron-overloaded rats resulted in significant decrease in serum total iron, TIBC, Tf, TS%, ferritin levels and AST and ALT activities and liver total iron, L-MDA and NO levels with significant increases in serum UIBC, albumin, total protein and total cholesterol levels and in liver GSH, CAT and SOD activities compared with the IOL group. This study provides in vivo evidence that rutin administration can improve the antioxidant defense systems against IOL-induced hepatic oxidative stress in rats. This protective effect in liver of iron-loaded rats may be due to both antioxidant and metal chelation activities.

Effects of different doses and duration of iron supplementation on curing iron deficiency anemia: an experimental study

Many controversies persist with respect to the dosage and therapeutic duration concerning iron deficiency anemia (IDA) treatment. To identify the most suitable cure, this study evaluated the effect of iron supplementation with different doses and for different time periods in rats with iron deficiency anemia. The rats were randomly divided into five groups [normal control (NC), low- iron diet control (LC), normal doses of iron group (NI), middle dose of iron group (MI), and high dose of iron group (HI)]. Each group was subdivided into two subgroups (2 and 4 weeks). The rats were maintained on low-iron diets and treated with oral iron dextran at different dosages. Finally, we investigated red blood cell parameters, iron absorption and metabolism, oxidative stress, and the antioxidant capacity. Our study indicated that through the administration of normal dose iron by gavage to IDA rats, the levels of the red blood cell parameters can be restored in only 2 weeks. In the HI group, iron absorption and transferrin receptor expressions were markedly reduced after 2 weeks. However, the iron content, ferritin and hepcidin expressions were notably increased, and the changes were more apparent after 4 weeks. With increasing doses of iron supplementation and durations of treatment, the liver malondialdehyde (MDA) content in the LC, MI, and HI groups was markedly increased, whereas the superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities were obviously reduced. This study demonstrated that the dose of iron treatment for IDA should be controlled in a safe range, and a reasonable duration is also critical for IDA therapeutics.

Association of hepcidin mRNA expression with hepatocyte iron accumulation and effects of antiviral therapy in chronic hepatitis C infection

BACKGROUND

Iron overload is frequently observed in patients with chronic hepatitis C (CHC) and is associated with the increased risk of liver fibrosis and carcinogenesis. Hepcidin is a regulator of iron homeostasis and a component of innate immunity. Based on experimental studies, iron overload might be a result of low hepcidin synthesis in CHC.

OBJECTIVES

The aim of this case-control study was to assess hepcidin mRNA expression in liver tissue of patients with CHC in terms of iron metabolism parameters, hemochromatosis (HFE) gene mutations, disease activity, and efficacy of antiviral treatment with pegylated interferon and ribavirin.

PATIENTS AND METHODS

A total of 31 patients with CHC, who were qualified for antiviral therapy, were compared with 19 patients with chronic hepatitis B (CHB). In both groups, liver function tests and serum iron parameters were assayed and hepcidin mRNA expression was measured in liver specimens using real time PCR with normalization to reference genes mRNA of stable expression.

RESULTS

Patients with CHC had lower hepcidin mRNA expression and more frequently iron deposits in hepatocytes than subjects with CHB did. In CHC group, hepcidin mRNA expression was positively correlated with alanine aminotransferase activity and serum iron concentration. Low expression of hepcidin had no correlation with tissue iron overload in those with CHC. In univariate analysis, HCV viral load and efficacy of antiviral treatment were not significantly associated with hepcidin mRNA expression.

CONCLUSIONS

Further studies on the role of hepcidin in pathogenesis of CHC are needed to assess the potency of its use in antiviral treatment.

Iron, oxidative stress and gestational diabetes

Both iron deficiency and hyperglycemia are highly prevalent globally for pregnant women. Iron supplementation is recommended during pregnancy to control iron deficiency. The purposes of the review are to assess the oxidative effects of iron supplementation and the potential relationship between iron nutrition and gestational diabetes. High doses of iron (~relative to 60 mg or more daily for adult humans) can induce lipid peroxidation in vitro and in animal studies. Pharmaceutical doses of iron supplements (e.g., 10× RDA or more for oral supplements or direct iron supplementation via injection or addition to the cell culture medium) for a short or long duration will induce DNA damage. Higher heme-iron intake or iron status measured by various biomarkers, especially serum ferritin, might contribute to greater risk of gestational diabetes, which may be mediated by iron oxidative stress though lipid oxidation and/or DNA damage. However, information is lacking about the effect of low dose iron supplementation (≤60 mg daily) on lipid peroxidation, DNA damage and gestational diabetes. Randomized trials of low-dose iron supplementation (≤60 mg daily) for pregnant women are warranted to test the relationship between iron oxidative stress and insulin resistance/gestational diabetes, especially for iron-replete women.

Novel aspects of the liver microenvironment in hepatocellular carcinoma pathogenesis and development

Hepatocellular carcinoma (HCC) is a prevalent primary liver cancer that is derived from hepatocytes and is characterised by high mortality rate and poor prognosis. While HCC is driven by cumulative changes in the hepatocyte genome, it is increasingly recognised that the liver microenvironment plays a pivotal role in HCC propensity, progression and treatment response. The microenvironmental stimuli that have been recognised as being involved in HCC pathogenesis are diverse and include intrahepatic cell subpopulations, such as immune and stellate cells, pathogens, such as hepatitis viruses, and non-cellular factors, such as abnormal extracellular matrix (ECM) and tissue hypoxia. Recently, a number of novel environmental influences have been shown to have an equally dramatic, but previously unrecognized, role in HCC progression. Novel aspects, including diet, gastrointestinal tract (GIT) microflora and circulating microvesicles, are now being recognized as increasingly important in HCC pathogenesis. This review will outline aspects of the HCC microenvironment, including the potential role of GIT microflora and microvesicles, in providing new insights into tumourigenesis and identifying potential novel targets in the treatment of HCC.

Hepatic iron overload and hepatocellular carcinoma

In recent years it has become increasingly evident that excess body iron may be complicated by the supervention of hepatocellular carcinoma (HCC). Hereditary hemochromatosis (HH) was the first condition in which hepatic iron overload was shown to predispose to the development of HCC. The inherited predisposition to excessive absorption of dietary iron in HH is almost always the result of homozygosity of the C282Y mutation of the HFE gene, which causes inappropriately low secretion of hepcidin. HCC develops in 8-10% of patients with HH and is responsible for approximately 45% of deaths in the HCC patients. Cirrhosis is almost always present when HCC is diagnosed. Dietary iron overload is a condition which occurs in rural-dwelling Black Africans in southern Africa as a result of the consumption, over time, of large volumes of alcohol home-brewed in iron containers and having, as a consequence, a high iron content. Iron loading of the liver results and may be complicated by malignant transformation of the liver (relative risk of approximately 10.0). Accompanying cirrhosis does occur but is less common than that in HH. The development of HCC as a consequence of increased dietary iron, and the fact that it may develop in the absence of cirrhosis, has been confirmed in an animal model. Drinking water with a high iron content might contribute to the high incidence of HCC in parts of Taiwan. The metabolic syndrome [obesity, insulin resistance type 2 (or diabetes mellitus type 2), non-alcoholic fatty liver or non-alcoholic steatohepatitis] has in recent years become a major public health problem in some resource-rich countries. A link between excess body iron and insulin resistance or the metabolic syndrome has become apparent. The metabolic syndrome may be complicated by the supervention of HCC, and recent evidence suggests that increased body iron may contribute to this complication.

Electron Therapy Attenuated Elevated Alanine Aminotransferase and Oxidative Stress Values in Type 2 Diabetes-Induced Nonalcoholic Steatohepatitis of Rats

Chronic oxidative stress plays a key role in the progression of nonalcoholic steatohepatitis (NASH). We examined the efficacy of antioxidative electron treatment on type 2 diabetes-induced NASH in a rat model. We established NASH model rats, induced by neonatal administration of streptozotocin and a high-fat diet, which exhibited pathologically high values of alanine aminotransferase (ALT), glucose, and malondialdehyde (MDA). The rats were exposed to electron discharge at very low energy for 4 weeks; this dose results in the reduction of Fe(3+) and glutathione disulfide in vitro. Serum ALT values were increased from baseline (8 weeks) to 125.0 ± 13 U/L at 10 weeks in the control group. In contrast, the values in the treated group did not show any increase at 10 weeks [87 ± 10 U/L (p = 0.0391)]. Hepatic MDA levels were also significantly decreased at 12 weeks (p < 0.05), but 8-hydroxy-2'-deoxyguanosine values were not statistically significant (p = 0.076). A gradual but steadily decreasing trend from initially high glucose levels was observed, though the values were not significant in 12-week-old animals (p = 0.074). However, the serum values of MDA, ALT, and glucose were well correlated. The progression of fibrosis as measured by increased serum levels of hyaluronic acid and histological examinations were not affected by the treatment in this model. Antioxidative electron treatment at very low energy attenuated the pathogenically elevated liver inflammation and oxidative stress, together with presumably impaired glucose metabolism in NASH rat model.

The association between frequency of vigorous physical activity and hepatobiliary cancers in the NIH-AARP Diet and Health Study

Despite a potential preventive effect of physical activity on hepatobiliary cancer, little information is available on the relation between the two. We studied the association between frequency of vigorous physical activity and hepatobiliary cancer among 507,897 participants of the NIH-AARP Diet and Health Study, aged 50-71 years at baseline in 1995/1996. During 10 years of follow-up, 628 incident cases of liver cancer and 317 cases of extrahepatic biliary tract cancer were registered. Physical activity levels were assigned according to the frequency of engagement in 20 min or more of vigorous physical activity per week: never/rarely (lowest level), less than once per week, 1-2 times per week, 3-4 times per week, 5 or more times per week (highest level). Using Cox regression, multivariate-adjusted relative risks (RR) comparing the highest with the lowest level of physical activity revealed a statistically significant decreased risk for liver cancer (RR = 0.64, 95% confidence interval (CI) = 0.49-0.84, p-trend <0.001), particularly hepatocellular carcinoma (RR = 0.56, 95% CI = 0.41-0.78, p-trend <0.001), independent of body mass index. By comparison, multivariate analyses indicated that physical activity was not statistically significantly associated with extrahepatic bile duct cancer (RR = 0.86, 95% CI = 0.45-1.65), ampulla of Vater cancer (RR = 0.66, 95% CI = 0.29-1.48), or gallbladder cancer (RR = 0.63, 95% CI = 0.33-1.21). These results suggest a potential preventive effect of physical activity on liver cancer but not extrahepatic biliary tract cancer, independent of body mass index.

Threshold dose of liver tumor promoting effect of β-naphthoflavone in rats

To determine the threshold dose of β-Naphthoflavone (BNF) that induces hepatocellular tumor promoting effects, reactive oxygen species (ROS) generation and thiobarbituric acid-reactive substance (TBARS) formation, and drug-metabolizing enzymes that protect against ROS generation, two-stage liver carcinogenesis model was used. Partial hepatectomized rats (n = 11 to 12) were fed diets containing 0, 0.03, 0.06, 0.125 or 0.25% BNF for 6 weeks after an intraperitoneal injection of N-diethylnitrosamine (DEN) to initiate hepatocarcinogenesis. Histopathologically, glutathione S-transferase placental form (GST-P)-positive foci significantly increased in rats given 0.25% BNF. No marked changes in ROS production and TBARS contents were observed between the BNF treated and DEN alone groups. Real-time RT-PCR showed that the expression of Cyp1a1, Cyp1a2, Cyp1b1 and Nqo1 significantly increased in the groups given 0.03% BNF or more, but Ugt1a6, Akr7a3 and Gstm1 significantly increased in the groups given 0.125% BNF or more. Gpx2 and Yc2 significantly increased in the groups given 0.06% BNF or more and 0.25% BNF, respectively. Inflammation-related genes such as Ccl2, Mmp12, Serpine1 and Cox-2 significantly increased in the 0.25% BNF group. In immunohistochemistry, the number of cyclooxygenase-2 (COX-2)-positive cells increased in rats given 0.25% BNF. These results suggest that 0.25% BNF is the threshold dose for liver tumor promotion, and the fact that inflammation-related genes and COX-2 protein increased in the 0.25% BNF group strongly suggests that inflammation is involved in the liver tumor promoting effect of BNF in rats.

Iron overload and toxicity: implications for anesthesiologists

Conditions leading to iron overload range from rare hereditary disorders to more common medical conditions associated with chronic blood transfusions. Iron overload has deleterious effects on various vital organs (eg, liver, heart, and endocrine glands). Serum ferritin (in conjunction with transferrin saturation) is the most widely used test to evaluate iron burden and to screen for iron overload. The management plan should be adjusted to account for iron overload and potential consequences of liver, heart, and other organ involvement.

Immune cells and hepatocytes express glycosylphosphatidylinositol-anchored ceruloplasmin at their cell surface

BACKGROUND

Ceruloplasmin is a positive acute-phase protein with both anti- and pro-oxidant activities, thus having still unclear physiological functions in inflammatory processes. Importantly, ceruloplasmin has been implicated in iron metabolism due to its ferroxidase activity, assisting ferroportin on cellular iron efflux. Ceruloplasmin can be expressed as a secreted or as a membrane glycosylphosphatidylinositol-anchored protein (GPI-ceruloplasmin), this latter one being reported as expressed mostly in the brain.

DESIGN AND METHODS

We studied the expression of both ceruloplasmin isoforms in human peripheral blood lymphocytes, monocytes, mouse macrophages and human hepatocarcinoma cell line HepG2, using immunofluorescence and immunoblotting techniques. Co-localization of ceruloplasmin and ferroportin was also investigated by immunofluorescence in mouse macrophages.

RESULTS

Ceruloplasmin was detected by immunoblotting and immunofluorescence in membrane and cytosol of all cell types. The cell surface ceruloplasmin was identified as the GPI-isoform and localized in lipid rafts from monocytes, macrophages and HepG2 cells. In macrophages, increased expression levels and co-localization of ferroportin and GPI-ceruloplasmin in cell surface lipid rafts were observed after iron treatment. Such iron upregulation of ceruloplasmin was not observed in HepG2.

CONCLUSIONS

Our results revealed an unexpected ubiquitous expression of the GPI-ceruloplasmin isoform in immune and hepatic cells. Different patterns of regulation of ceruloplasmin in these cells may reflect distinct physiologic functions of this oxidase. In macrophages, GPI-ceruloplasmin and ferroportin likely interact in lipid rafts to export iron from cells. Precise knowledge about ceruloplasmin isoforms expression and function in various cell types will help to clarify the role of ceruloplasmin in many diseases related to iron metabolism, inflammation and oxidative biology.

Immunochemical detection of oxidatively damaged DNA

Oxidatively damaged DNA is implicated in various diseases, including neurodegenerative disorders, cancer, diabetes, cardiovascular and inflammatory diseases as well as aging. Several methods have been developed to detect oxidatively damaged DNA. They include chromatographic techniques, the Comet assay, (32)P-postlabelling and immunochemical methods that use antibodies to detect oxidized lesions. In this review, we discuss the detection of 8-oxo-7,8-dihydro-29-deoxyguanosine (8-oxodG), the most abundant oxidized nucleoside. This lesion is frequently used as a marker of exposure to oxidants, including environmental pollutants, as well as a potential marker of disease progression. We concentrate on studies published between the years 2000 and 2011 that used enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry to detect 8-oxodG in humans, laboratory animals and in cell lines. Oxidative damage observed in these organisms resulted from disease, exposure to environmental pollutants or from in vitro treatment with various chemical and physical factors.

Iron deprivation suppresses hepatocellular carcinoma growth in experimental studies

PURPOSE

Hepatocellular carcinoma (HCC) is the third most common cause of cancer-related death, and iron overload is a significant risk factor in the development of HCC. In this study, we investigated the potential application of depriving iron by a novel iron chelator, thiosemicarbazone-24 (TSC24), in HCC treatment.

EXPERIMENTAL DESIGN

Two HCC cell lines and HFE knockout (HFE(-/-)) mice were used to determine iron chelation efficiency of TSC24. The anticancer effects of TSC24 on HCC were analyzed in vitro and in athymic xenograft mouse models.

RESULTS

Treatment with TSC24 significantly decreased the cellular iron concentration in hepatoma cells and the serum iron concentration in HFE(-/-) mice by blocking iron uptake and interfering with normal regulation of iron levels. Moreover, the viability of HCC cell lines was reduced by TSC24. Confirming the mechanism of the agent, this decrease in viability could be partially rescued by addition of exogenous iron. TSC24 also suppressed tumor growth in athymic mice bearing human HCC xenografts in a concentration-dependent manner, without apparent toxicity in parallel with a decrease in the serum iron level. Further studies revealed that TSC24 efficiently triggered cell-cycle arrest and apoptosis in Hep3B and HepG2 cell lines.

CONCLUSIONS

TSC24 is a potent iron chelator that suppresses human HCC tumor growth by disrupting iron homeostasis, reducing available iron, and triggering cell-cycle arrest and apoptosis, without apparent host toxicity at effective doses. Thus, TSC24 shows great potential for the treatment of HCC.

Hepatocellular carcinoma in African Blacks: Recent progress in etiology and pathogenesis

Occult hepatitis B virus (HBV) infection was shown to be present in 75% of Black Africans with hepatocellular carcinoma (HCC) in whom the tumor was hitherto not thought to be caused by chronic HBV infection. The association between chronic HBV infection and the development of the tumor is thus even closer than was originally thought. HBV viral load was found to be significantly higher in patients with HCC than in Black African controls. As in other populations, HBV e antigen-positive patients with hepatocellular carcinoma had significantly higher viral loads than patients negative for this antigen. The significance of this finding is discussed. The risk for HCC development with genotype A of HBV, the predominant genotype in African isolates, has not been investigated. Genotype A was shown to be 4.5 times more likely than other genotypes to cause HCC in Black Africans, and tumours occurred at a significantly younger age. Increasing numbers of patients with human immunodeficiency virus (HIV) and HBV co-infection are being reported to develop HCC. A preliminary case/control comparison supports the belief that HIV co-infection enhances the hepatocarcinogenic potential of HBV. A study from The Gambia provides the first evidence that dietary exposure to aflatoxin B(1) may cause cirrhosis and that this may play a contributory role in the pathogenesis of aflatoxin-induced HCC. An animal model has provided experimental support for the clinical evidence that dietary iron overload in the African is directly hepatocarcinogenic, in addition to causing the tumor indirectly through the development of cirrhosis.

Clinical consequences of iron overload from chronic red blood cell transfusions, its diagnosis, and its management by chelation therapy

Iron overload from chronic transfusion therapy can be extremely toxic. Excess transfusional iron is deposited in the liver, heart, and other organs as free iron, which can cause organ dysfunction and damage over time. Increased awareness of the risk of iron overload in patients requiring chronic transfusion therapy is needed, and such patients should be screened for hyperferritinemia. Those with serial serum ferritin levels exceeding 1000 ng/mL and a total infused red blood cell volume of 120 mL/kg of body weight or more should be treated with chelation therapy and then monitored to ensure that treatment adequately reduces iron levels.

Spontaneous hepatocellular carcinoma in captive prosimians

Spontaneous hepatocellular carcinoma has been reported as a relatively common neoplasm in prosimians; however, the cause is unknown. To investigate possible pathogenic mechanisms, the authors performed a review of all adult animals from a captive prosimian population that had postmortem examinations over the past 10 years. They performed a detailed histologic evaluation of all suspected proliferative liver lesions and diagnosed hepatocellular carcinoma in 14 of 145 lemurs (9.7%). Affected animals ranged between the ages of 6 and 40 years old. The tumors had an unusually aggressive growth pattern for animal species; metastasis to the lungs or mediastinum was evident in 7 of 14 animals. Thirty-one animals-9 with hepatocellular carcinomas and 22 age-matched controls without hepatic neoplasia-were tested to evaluate the relationship between hepatic iron stores (as well as other trace metals) and the presence of hepatocellular carcinoma. There was no difference between the hepatic iron, copper, or molybdenum in lemurs with hepatocellular carcinoma and those without, suggesting that iron is not a key element in the pathogenesis of liver tumor formation. Analysis of 22 serum samples from animals with and without liver tumors indicated no evidence of active infection with a hepadnavirus, the virus family that includes hepatitis B virus. Hepatitis C virus and aflatoxin B1 were considered as potential causes and ruled out owing to lack of associated histopathologic lesions. In conclusion, hepatocellular neoplasia is relatively common in captive prosimians, although previously suspected etiologies seem unlikely.

Modulation of Iron-Regulatory Genes in Human Hepatocellular Carcinoma and Its Physiological Consequences

Hepatocellular carcinoma (HCC) commonly develops in patients with underlying chronic liver disease. Additionally, the tumorous lesions of HCC patients are consistently characterized by the lack of iron accumulation even when arising in iron-loaded liver. However, the molecular mechanism leading to this observed phenomenon is currently poorly understood. In this study, all tumorous tissues from 24 HCC patients with chronic HBV infection were stained negative for iron when histologically assessed by Perls’ Prussian blue stain, whereas excess iron deposits were present in 17 of the 24 adjacent non-tumorous liver tissues. To elucidate the concerted regulation of iron homeostasis in these patients, we studied the gene expression profiling of 42 relevant iron-regulatory genes in the tumorous and adjacent non-tumorous liver tissues of these HCC patients along with 10 normal liver controls. Expression for most of the iron-regulatory genes, including hepcidin, transferrin receptor 2 (TfR2), transferrin (Tf), ceruloplasmin (Cp) and iron regulatory protein 1 (IRP1), were significantly down-regulated in the tumorous tissues of these patients compared to the adjacent non-tumorous liver tissues and normal liver controls. On the other hand, expression of hepcidin, TfR2, ferroportin 1 and DMT1 were significantly up-regulated in iron-loaded non-cirrhotic non-tumorous liver tissues as compared with normal liver controls. Hence, the reduction of hepcidin expression within the iron-depleted tumorous lesions likely reflects the physiological consequence of the obligate demand for iron in the rapidly growing neoplastic cells, whereas the up-regulation of hepcidin expression in the iron-loaded adjacent non-tumorous liver tissues is likely a physiological response.