Altered lipid profile, oxidative status and hepatitis B virus interactions in human hepatocellular carcinoma

Insights into the Management of Chronic Hepatitis in Children-From Oxidative Stress to Antioxidant Therapy

Recent research has generated awareness of the existence of various pathophysiological pathways that contribute to the development of chronic diseases; thus, pro-oxidative factors have been accepted as significant contributors to the emergence of a wide range of diseases, from inflammatory to malignant. Redox homeostasis is especially crucial in liver pathology, as disturbances at this level have been linked to a variety of chronic diseases. Hepatitis is an umbrella term used to describe liver inflammation, which is the foundation of this disease regardless of its cause. Chronic hepatitis produces both oxidative stress generated by hepatocyte inflammation and viral inoculation. The majority of hepatitis in children is caused by a virus, and current studies reveal that 60-80% of cases become chronic, with many young patients still at risk of advancing liver damage. This review intends to emphasize the relevance of understanding these pathological redox pathways, as well as the need to update therapeutic strategies in chronic liver pathology, considering the beneficial effects of antioxidants.

The Role of Glutathione in Selected Viral Diseases

During inflammatory processes, immunocompetent cells are exposed to substantial amounts of free radicals and toxic compounds. Glutathione is a cysteine-containing tripeptide that is an important and ubiquitous antioxidant molecule produced in human organs. The intracellular content of GSH regulates the detoxifying capacity of cells, as well as the inflammatory and immune response. GSH is particularly important in the liver, where it serves as the major non-protein thiol involved in cellular antioxidant defense. There are numerous causes of hepatitis. The inflammation of the liver can be caused by a variety of infectious viruses. The relationship between oxidative stress and the hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), and hepatitis E virus (HEV) infection is not fully known. The aim of this study was to examine the relationship between hepatotropic viruses and glutathione status, including reduced glutathione (GSH) and oxidized glutathione (GSSG), as well as antioxidant enzymes, e.g., glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione-S-transferase (GST) in liver diseases.

Plasma Lipidomics Analysis Reveals the Potential Role of Lysophosphatidylcholines in Abdominal Aortic Aneurysm Progression and Formation

Abdominal aortic aneurysm (AAA) is hallmarked by irreversible dilation of the infrarenal aorta. Lipid deposition in the aortic wall and the potential importance of a lipid disorder in AAA etiology highlight the need to explore lipid variation during AAA development. This study aimed to systematically characterize the lipidomics associated with AAA size and progression. Plasma lipids from 106 subjects (36 non-AAA controls and 70 AAA patients) were comprehensively analyzed using untargeted lipidomics. An AAA animal model was established by embedding angiotensin-II pump in ApoE^-/- mice for four weeks and blood was collected at 0, 2 and 4 weeks for lipidomic analysis. Using a false-discovery rate (FDR) < 0.05, a group of lysophosphatidylcholines (lysoPCs) were specifically decreased in AAA patients and mice. LysoPCs were principally lower in the AAA patients with larger diameter (diameter > 50 mm) than those with a smaller size (30 mm < diameter < 50 mm), and levels of lysoPCs were also found to be decreased with modelling time and aneurysm formation in AAA mice. Correlation matrices between lipids and clinical characteristics identified that the positive correlation between lysoPCs and HDL-c was reduced and negative correlations between lysoPCs and CAD rate, lysoPCs and hsCRP were converted to positive correlations in AAA compared to control. Weakened positive correlations between plasma lysoPCs and circulating HDL-c in AAA suggested that HDL-lysoPCs may elicit instinctive physiological effects in AAA. This study provides evidence that reduced lysoPCs essentially underlie the pathogenesis of AAA and that lysoPCs are promising biomarkers for AAA development.

The altered lipidome of hepatocellular carcinoma

Alterations in metabolic pathways are a hallmark of cancer. A deeper understanding of the contribution of different metabolites to carcinogenesis is thus vitally important to elucidate mechanisms of tumor initiation and progression to inform therapeutic strategies. Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death worldwide and its altered metabolic landscape is beginning to unfold with the advancement of technologies. In particular, characterization of the lipidome of human HCCs has accelerated, and together with biochemical analyses, are revealing recurrent patterns of alterations in glycerophospholipid, sphingolipid, cholesterol and bile acid metabolism. These widespread alterations encompass a myriad of lipid species with numerous roles affecting multiple hallmarks of cancer, including aberrant growth signaling, metastasis, evasion of cell death and immunosuppression. In this review, we summarize the current trends and findings of the altered lipidomic landscape of HCC and discuss their potential biological significance for hepatocarcinogenesis.

Optimized Systematic Review Tool: Application to Candidate Biomarkers for the Diagnosis of Hepatocellular Carcinoma

This review aims to develop an appropriate review tool for systematically collating metabolites that are dysregulated in disease and applies the method to identify novel diagnostic biomarkers for hepatocellular carcinoma (HCC). Studies that analyzed metabolites in blood or urine samples where HCC was compared with comparison groups (healthy, precirrhotic liver disease, cirrhosis) were eligible. Tumor tissue was included to help differentiate primary and secondary biomarkers. Searches were conducted on Medline and EMBASE. A bespoke "risk of bias" tool for metabolomic studies was developed adjusting for analytic quality. Discriminant metabolites for each sample type were ranked using a weighted score accounting for the direction and extent of change and the risk of bias of the reporting publication. A total of 84 eligible studies were included in the review (54 blood, 9 urine, and 15 tissue), with six studying multiple sample types. High-ranking metabolites, based on their weighted score, comprised energy metabolites, bile acids, acylcarnitines, and lysophosphocholines. This new review tool addresses an unmet need for incorporating quality of study design and analysis to overcome the gaps in standardization of reporting of metabolomic data. Validation studies, standardized study designs, and publications meeting minimal reporting standards are crucial for advancing the field beyond exploratory studies.

Accumulation of cholesterol, triglycerides and ceramides in hepatocellular carcinomas of diethylnitrosamine injected mice

BACKGROUND

Dysregulated lipid metabolism is critically involved in the development of hepatocellular carcinoma (HCC). The respective metabolic pathways affected in HCC can be identified using suitable experimental models. Mice injected with diethylnitrosamine (DEN) and fed a normal chow develop HCC. For the analysis of the pathophysiology of HCC in this model a comprehensive lipidomic analysis was performed.

METHODS

Lipids were measured in tumor and non-tumorous tissues by direct flow injection analysis. Proteins with a role in lipid metabolism were analysed by immunoblot. Mann-Whitney U-test or paired Student´s t-test were used for data analysis.

RESULTS

Intra-tumor lipid deposition is a characteristic of HCCs, and di- and triglycerides accumulated in the tumor tissues of the mice. Peroxisome proliferator-activated receptor gamma coactivator 1 alpha, lipoprotein lipase and hepatic lipase protein were low in the tumors whereas proteins involved in de novo lipogenesis were not changed. Higher rates of de novo lipogenesis cause a shift towards saturated acyl chains, which did not occur in the murine HCC model. Besides, LDL-receptor protein and cholesteryl ester levels were higher in the murine HCC tissues. Ceramides are cytotoxic lipids and are low in human HCCs. Notably, ceramide levels increased in the murine tumors, and the simultaneous decline of sphingomyelins suggests that sphingomyelinases were involved herein. DEN is well described to induce the tumor suppressor protein p53 in the liver, and p53 was additionally upregulated in the tumors.

CONCLUSIONS

Ceramides mediate the anti-cancer effects of different chemotherapeutic drugs and restoration of ceramide levels was effective against HCC. High ceramide levels in the tumors makes the DEN injected mice an unsuitable model to study therapies targeting ceramide metabolism. This model is useful for investigating how tumors evade the cytotoxic effects of ceramides.

Liver Lipids of Patients with Hepatitis B and C and Associated Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) still remains a difficult to cure malignancy. In recent years, the focus has shifted to lipid metabolism for the treatment of HCC. Very little is known about hepatitis B virus (HBV) and C virus (HCV)-related hepatic lipid disturbances in non-malignant and cancer tissues. The present study showed that triacylglycerol and cholesterol concentrations were similar in tumor adjacent HBV and HCV liver, and were not induced in the HCC tissues. Higher levels of free cholesterol, polyunsaturated phospholipids and diacylglycerol species were noted in non-tumorous HBV compared to HCV liver. Moreover, polyunsaturated phospholipids and diacylglycerols, and ceramides declined in tumors of HBV infected patients. All of these lipids remained unchanged in HCV-related HCC. In HCV tumors, polyunsaturated phosphatidylinositol levels were even induced. There were no associations of these lipid classes in non-tumor tissues with hepatic inflammation and fibrosis scores. Moreover, these lipids did not correlate with tumor grade or T-stage in HCC tissues. Lipid reprogramming of the three analysed HBV/HCV related tumors mostly resembled HBV-HCC. Indeed, lipid composition of non-tumorous HCV tissue, HCV tumors, HBV tumors and HBV/HCV tumors was highly similar. The tumor suppressor protein p53 regulates lipid metabolism. The p53 and p53S392 protein levels were induced in the tumors of HBV, HCV and double infected patients, and this was significant in HBV infection. Negative correlation of tumor p53 protein with free cholesterol indicates a role of p53 in cholesterol metabolism. In summary, the current study suggests that therapeutic strategies to target lipid metabolism in chronic viral hepatitis and associated cancers have to consider disease etiology.

Impact of 17β-HSD12, the 3-ketoacyl-CoA reductase of long-chain fatty acid synthesis, on breast cancer cell proliferation and migration

Metabolic reprogramming of tumor cells involves upregulation of fatty acid (FA) synthesis to support high bioenergetic demands and membrane synthesis. This has been shown for cytosolic synthesis of FAs with up to 16 carbon atoms. Synthesis of long-chain fatty acids (LCFAs), including ω-6 and ω-3 polyunsaturated FAs, takes place at the endoplasmic reticulum. Despite increasing evidence for an important role of LCFAs in cancer, the impact of their synthesis in cancer cell growth has scarcely been studied. Here, we demonstrated that silencing of 17β-hydroxysteroid dehydrogenase type 12 (17β-HSD12), essentially catalyzing the 3-ketoacyl-CoA reduction step in LCFA production, modulates proliferation and migration of breast cancer cells in a cell line-dependent manner. Increased proliferation and migration after 17β-HSD12 knockdown were partly mediated by metabolism of arachidonic acid towards COX2 and CYP1B1-derived eicosanoids. Decreased proliferation was rescued by increased glucose concentration and was preceded by reduced ATP production through oxidative phosphorylation and spare respiratory capacity. In addition, 17β-HSD12 silencing was accompanied by alterations in unfolded protein response, including a decrease in CHOP expression and increase in eIF2α activation and the folding chaperone ERp44. Our study highlights the significance of LCFA biosynthesis for tumor cell physiology and unveils unknown aspects of breast cancer cell heterogeneity.

Role of lipids in pathophysiology, diagnosis and therapy of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is an aggressive and widespread cancer. Patients with liver cirrhosis of different aetiologies are at a risk to develop HCC. It is important to know that in approximately 20% of cases primary liver tumors arise in a non-cirrhotic liver. Lipid metabolism is variable in patients with chronic liver diseases, and lipid metabolites involved therein do play a role in the development of HCC. Of note, lipid composition of carcinogenic tissues differs from non-affected liver tissues. High cholesterol and low ceramide levels in the tumors protect the cells from oxidative stress and apoptosis, and do also promote cell proliferation. So far, detailed characterization of the mechanisms by which lipids enable the development of HCC has received little attention. Evaluation of the complex roles of lipids in HCC is needed to better understand the pathophysiology of HCC, the later being of paramount importance for the development of urgently needed therapeutic interventions. Disturbed hepatic lipid homeostasis has systemic consequences and lipid species may emerge as promising biomarkers for early diagnosis of HCC. The challenge is to distinguish lipids specifically related to HCC from changes simply related to the underlying liver disease. This review article discusses aberrant lipid metabolism in patients with HCC.

A prognostic fingerprint in liver transplantation for hepatocellular carcinoma based on plasma metabolomics profiling

INTRODUCTION

Tumor recurrence is a major cause of post-transplant mortality in liver transplantation for hepatocellular carcinoma (HCC). This study aimed to explore an effective noninvasive approach to accurately predict post-transplant tumor recurrence.

MATERIALS AND METHODS

Metabolomics profiling was performed on pre-operative plasma from 122 HCC patients undergoing liver transplantation, 52 healthy controls (HC) and 25 liver cirrhosis (LC) patients.

RESULTS

Five prognostic metabolites were identified by univariate analysis (P < 0.01), including phosphatidylcholine (PC) (16:0/P-18:1), PC(18:2/OH-16:0), PC(o-16:0/20:4), nutriacholic acid and 2-oxo-4-methylthiobutanoic acid. In the HCC group, PC(o-16:0/20:4), nutriacholic acid and 2-oxo-4-methylthiobutanoic acid were decreased, while PC(18:2/OH-16:0) was elevated compared with the LC group (e < 0.05). PC(16:0/P-18:1) was associated with tumor size, vascular invasion, and neutrophil-lymphocyte ratio (NLR; P < 0.05). Moreover, PC(18:2/OH-16:0) was also related to tumor number and NLR (P < 0.05). Multivariate cox regression showed that PC(16:0/P-18:1), PC(18:2/OH-16:0), nutriacholic acid and alpha-fetoprotein (AFP) were independent risk factors for tumor recurrence (P < 0.01). A prognostic fingerprint was established as a nomogram, which divided the patients into low risk (n = 45), moderate risk (n = 48) and highrisk groups (n = 29) with discriminated prognosis (P < 0.001). In patients fulfilling the Hangzhou criteria, the fingerprint/nomogram could also successfully stratify the patients into two groups with different recurrence risk (P < 0.05).

CONCLUSIONS

The established pre-operative plasma fingerprint/nomogram is efficient in the prediction of recurrence risk, which could facilitate candidate selection in liver transplantation for HCC.

Metabolomic Characterization of Human Model of Liver Rejection Identifies Aberrancies Linked to Cyclooxygenase (COX) and Nitric Oxide Synthase (NOS)

BACKGROUND Acute liver rejection (ALR), a significant complication of liver transplantation, burdens patients, healthcare payers, and the healthcare providers due to an increase in morbidity, cost, and resources. Despite clinical resolution, ALR is associated with an increased risk of graft loss. A unique protocol of delayed immunosuppression used in our institute provided a model to characterize metabolomic profiles in human ALR. MATERIAL AND METHODS Twenty liver allograft biopsies obtained 48 hours after liver transplantation in the absence of immunosuppression were studied. Hepatic metabolites were quantitated in these biopsies by liquid chromatography and mass spectroscopy (LC/MS). Metabolite profiles were compared among: 1) biopsies with reperfusion injury but no histological evidence of rejection (n=7), 2) biopsies with histological evidence of moderate or severe rejection (n=5), and 3) biopsies with histological evidence of mild rejection (n=8). RESULTS There were 133 metabolites consistently detected by LC/MS and these were prioritized using variable importance to projection (VIP) analysis, comparing moderate or severe rejection vs. no rejection or mild rejection using partial least squares discriminant statistical analysis (PLS-DA). Twenty metabolites were identified as progressively different. Further PLS-DA using these metabolites identified 3 metabolites (linoleic acid, γ-linolenic acid, and citrulline) which are associated with either cyclooxygenase or nitric oxide synthase functionality. CONCLUSIONS Hepatic metabolic aberrancies associated with cyclooxygenase and nitric oxide synthase function occur contemporaneous with ALR. Additional studies are required to better characterize the role of these metabolic pathways to enhance utility of the metabolomics approach in diagnosis and outcomes of ALR.

Phospholipid profiles and hepatocellular carcinoma risk and prognosis in cirrhotic patients

Background

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide. Phospholipids are now well-recognised players in tumour progression. Their metabolic tissue alterations can be associated with plasmatic modifications. The aim of this study was to evaluate the potential of the plasma phospholipid profile as a risk and prognostic biomarker in HCC.

Methods

Ninety cirrhotic patients with (cases) or without HCC (controls) were studied after matching for inclusion centre, age, gender, virus infection, cirrhosis duration and Child-Pugh grade. High-performance liquid chromatography coupled with tandem-mass spectrometry was used to quantify the main species of seven categories of phospholipids in plasma.

Results

Elevated concentrations of phosphatidylcholine (PC) 16:0/16:1 (p=0.0180), PC 16:0/16:0 (p=0.0327), PC 16:0/18:1 (p=0.0264) and sphingomyelin (SM) 18:2/24:1 (p=0.0379) and low concentrations of lysophosphatidylcholine 20:4 (0.0093) and plasmalogen-phosphatidylethanolamine (pPE) 16:0/20:4 (p=0.0463), pPE 18:0/20:4 (p=0.0077), pPE 18:0/20:5 (p=0.0163), pPE 18:0/20:3 (p=0.0463) discriminated HCC patients from cirrhotic controls. Two ceramide species were associated with increased HCC risk of death while lysophospholipids, a polyunsaturated phosphatidylinositol, some PC and SM species were associated with low risk of death in HCC patients in 1 and/or 3 years.

Conclusion

This study identified phospholipid profiles related to HCC risk in liver cirrhotic patients and showed for the first time the potential of some phospholipids in predicting HCC patient mortality.

Propyl gallate inhibits hepatocellular carcinoma cell growth through the induction of ROS and the activation of autophagy

The poor prognosis of hepatocellular carcinoma (HCC) has been attributed to a high frequency of tumor metastasis and recurrence even after successful surgical resection. With less than 30% of patients benefiting from curative treatment, alternative treatment regimens for patients with advanced HCC are needed. Propyl gallate (PG), a synthetic antioxidant used in preserving food and medicinal preparations, has been shown to induce cancer cell death, but the anticancer effects of PG in HCC are unclear. In the present study, we demonstrated that PG inhibited HCC cell proliferation in vitro and in zebrafish models in vivo in a dose- and time-dependent manner. PG also induced cell apoptosis and increased the number of necrotic cells in a time- and dose-dependent manner as determined using a high-content analysis system. We found that PG also increased the intracellular levels of superoxide and reactive oxidative stress as well as the formation of autophagosomes and lysosomes. Regarding the molecular mechanism, PG did not alter the levels of autophagy-related 5 (ATG5), ATG5/12 or Beclin-1 but increased the rate of the LC3-I to LC3-II conversion, suggesting autophagy induction. PG exposure increased the levels of the pro-apoptotic proteins cleaved caspase-3, cleaved PARP, Bax, and Bad and a decreased level of the anti-apoptotic protein Bcl-2. In conclusion, we demonstrate that PG inhibits HCC cell proliferation through enhanced ROS production and autophagy activation. Finally, PG-treated cells induced cell apoptosis and may be a new candidate for HCC therapy.

Comparison of hepatic and serum lipid signatures in hepatocellular carcinoma patients leads to the discovery of diagnostic and prognostic biomarkers

We compared hepatic and serum lipid changes in hepatocellular carcinoma (HCC) patients to have a better understanding of the molecular pathogenesis of this disease and discovery novel lipid biomarkers. Hepatic and serum lipid profiling was conducted in paired liver and serum samples from 50 HCC patients and 24 healthy controls. A total of 20 hepatic and 40 serum lipid signatures were identified, yet there was hardly any significant correlation between them. The results indicated that triglycerides and phosphatidylcholines contributed significantly to altered hepatic lipids, whereas triglycerides and phosphatidylethanolamine-based plasmalogens (PEp) contributed most to altered serum lipids. In serum, PEp (36:4) and (40:6) showed a fair capability to discriminate HCC patients from healthy controls, and were significantly associated with HCC tumor grades (p < 0.05), and thus were identified as potential diagnostic and prognostic biomarkers of HCC. These findings were confirmed by a validation study conducted in an independent cohort consisting of 18 HCC, 20 cirrhosis patients, and 20 healthy controls. This study suggests that hepatic and serum lipid signatures of HCC have to be considered as mostly independent, and the results imply potential roles of PEp species, particularly PEp (36:4) and (40:6), as serum biomarkers for HCC diagnosis and progression.

Changes of Oxidative Stress, Glutathione, and Its Dependent Antioxidant Enzyme Activities in Patients with Hepatocellular Carcinoma before and after Tumor Resection

The changes in and relationship between oxidative stress and the glutathione (GSH) antioxidant system in the plasma and tissues of patients with hepatocellular carcinoma (HCC) before and after tumor resection have not been clearly determined. We investigated the changes in oxidative stress, GSH status and its dependent antioxidant enzyme activities in HCC patients before and after tumor resection, and to determine the association of oxidative stress with GSH and its dependent antioxidant enzyme activities in plasma and tissues. This study employed a cross-sectional design. Forty-four men and 16 women with HCC were recruited. Fasting blood was drawn on the day before the tumor resection and one month after the tumor resection. HCC tissue and adjacent normal liver tissue were obtained at the time of surgical resection. Patients had significantly increased plasma malondialdehyde (MDA) and oxidized-low density lipoprotein levels but decreased GSH and oxidized GSH levels before tumor resection compared with the corresponding post-resection values. GSH and trolox equivalent antioxidant capacity (TEAC) levels and activities of GSH peroxidase were significantly increased while MDA level was significantly lower in HCC tissue when compared with the adjacent normal tissue. The pre-resection plasma MDA level was significantly correlated with pre-resection plasma GSH concentration, and MDA level in HCC and adjacent normal tissues. Pre-resection plasma GSH concentration was significantly correlated with GSH and TEAC level in HCC tissue. HCC patients had increased oxidative stress, decreased GSH, and lower dependent antioxidant capacities before tumor resection. However, hepatocellular tumor had increased GSH and TEAC levels as well as GSH peroxidase activities which might protect itself against increased oxidative stress.

Hepatitis B and its Relationship With Oxidative Stress

CONTEXT

Despite the great breakthroughs we have witnessed in the last 50 years in the prevention, diagnosis, and treatment of hepatitis B, we are still far from eradicating or even curing the disease. Achieving further progress in controlling this disease will not be possible without discovering the exact pathogenesis behind it. One prime suspect in the pathogenesis of various diseases is oxidative stress. This review will exclusively explore hepatitis B in the context of oxidative stress to obtain a more comprehensive clinical perspective on its pathogenesis and eventual medical therapy.

EVIDENCE ACQUISITION

We systematically searched PubMed, Google Scholar, Web of Science, EMBASE, and Scopus using an extensive list of keywords in the following three categories: 1) Hepatitis B and oxidation 2) Hepatitis B and antioxidant system 3) Effects of approved anti-hepatitis B drugs on redox status. All relevant articles were obtained and reviewed carefully after the exclusion criteria were deployed.

RESULTS

There is great evidence indicating extensive oxidative stress occurs in hepatitis B. This oxidative stress takes place on multiple levels, including lipid peroxidation, DNA oxidation, protein oxidation, and reactive oxygen and nitrogen species production. However, there are also conflicting results with regard to antioxidant therapy and antioxidant status in hepatitis B, some of which may be explained by the concept of "compensatory gaps." Nevertheless, further studies are indicated to reach a more thorough judgment.

CONCLUSIONS

Despite the presence of vast oxidative stress in hepatitis B, antioxidant therapy is not always effective as a treatment strategy, especially considering that antioxidants can act as "double-edged swords" or antioxidants; if not used at the right time or place or in the right combination, these substances can easily become pro-oxidants. Therefore, several studies will be needed to determine suitable antioxidant therapies. We propose the "2-step Combined Antioxidant Adjuvant Therapy for hepatitis B (2CAAT Hep B)" as a new strategy for antioxidant adjuvant therapy. We also suggest developing an international platform and database for antioxidant adjuvant therapy in hepatitis B (IPAATH and IDAATH) to canalize this field of research in a standardized direction, especially when complexity is a problem.

Ceramide and polyunsaturated phospholipids are strongly reduced in human hepatocellular carcinoma

Lipid composition affects membrane function, cell proliferation and cell death and is changed in cancer tissues. Hepatocellular carcinoma (HCC) is an aggressive cancer and this study aimed at a comprehensive characterization of hepatic and serum lipids in human HCC. Cholesteryl ester were higher in tumorous tissues (TT) compared to adjacent non-tumorous tissues (NT). Free cholesterol exerting cytotoxic effects was not changed. Phosphatidylethanolamine, -serine (PS) and -inositol but not phosphatidylcholine (PC) and lysophosphatidylcholine (LPC) were reduced in HCC tissues. Saturated species mostly increased and polyunsaturated species were diminished in all of these phospholipids. Ceramide (Cer) was markedly reduced in HCC tissues and higher levels of sphingomyelin suggest impaired sphingomyelinase activity as one of the underlying mechanisms. Importantly, ceramide in NT increased in HCC stage T3. Ceramide released from hepatocytes attracts immune cells and a positive association of the macrophage specific receptor CD163 with NT ceramide was identified. HCC associated lipid changes did not differ in patients suffering from type 2 diabetes. Protein levels of p53 were induced in TT and negatively correlated with Cer d18:1/16:0 and PS 36:1. Of the lipid species changed in HCC tissues only TT Cer d18:1/16:0, Cer d18:1/24:1, PC 38:6 and LPC 22:6 correlated with the respective serum levels. Our study demonstrates a considerably altered hepatic lipidome in HCC tissues. Ceramide was markedly reduced in HCC tissues, and therefore, raising ceramide levels specifically in the tumor represents a reasonable therapeutic approach for the treatment of this malignancy.

Differential modulation of the lipid metabolism as a model for cellular resistance to fumonisin B1-induced cytotoxic effects in vitro

Differential sensitivity of primary hepatocytes and Chang cells to the cancer promoter fumonisin B1 (FB1)-induced cytotoxic effects were investigated in relation to changes in membrane lipid distribution. In contrast to primary hepatocytes, Chang cells were resistant to FB1-induced cytotoxic effects. This was associated with a high cholesterol (Chol) and sphingomyelin (SM) and low phosphatidylcholine (PC) content, resulting in a significant (P<0.05) decrease in phosphatidylethanolamine (PE)/PC ratio, increased Chol/total phosphoglyceride (TPG) ratios and low total polyunsaturated fatty acids (PUFA) content in PC and PE, suggesting a more rigid membrane structure. High levels of C18:1 and reduced polyunsaturated fatty acid (PUFA) levels are likely to provide selective resistance to FB1-induced oxidative stress. FB1-associated lipid changes included decreases in SM and Chol, increases in sphinganine (Sa) and PE with the increases in key saturated, monounsaturated, and PUFAs in PE as key role players in the differential responses to FB1-induced cell growth responses in cells.

Dichlorodiphenyldichloroethylene exposure reduces r-GCS via suppressed Nrf2 in HepG2 cells

p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE), the major isomer of persistent 1,1-Bis(4-chlorophenyl)-2,2,2-trichloroethane metabolite, is highly associated with the risk of liver cancer. γ-glutamyl-cysteine synthetase (γ-GCS), which is the rate-limiting enzyme of glutathione (GSH) biosynthesis and an important scavenger of reactive oxygen species (ROS), is considered as a potential therapeutic target for many cancers. However, the association between the body burden of p,p'-DDE and γ-GCS has not been fully established. Here, we indicated that low doses of p,p'-DDE exposure promoted the proliferation and decreased γ-GCS activity of HepG2 cells in a dose- and time-dependent manner. In addition, p,p'-DDE elevated ROS content and attenuated glutathione peroxidase activity. This was accompanied with inhibitions of NF-E2-related factor 2 (Nrf2) at the mRNA and protein levels. ROS inhibitor supplement could significantly reverse these effects. Moreover, the addition of the proteasome inhibitor, MG132, strongly reversed the p,p'-DDE-reduced Nrf2 expression and γ-GCS activity. Consistently, GSH content was in line with the alteration of γ-GCS. Collectively, the results indicate that p,p'-DDE treatment downregulates γ-GCS activity in HepG2 cells by inducing ROS-mediated Nrf2 loss.

Soybean Oil Is More Obesogenic and Diabetogenic than Coconut Oil and Fructose in Mouse: Potential Role for the Liver

The obesity epidemic in the U.S. has led to extensive research into potential contributing dietary factors, especially fat and fructose. Recently, increased consumption of soybean oil, which is rich in polyunsaturated fatty acids (PUFAs), has been proposed to play a causal role in the epidemic. Here, we designed a series of four isocaloric diets (HFD, SO-HFD, F-HFD, F-SO-HFD) to investigate the effects of saturated versus unsaturated fat, as well as fructose, on obesity and diabetes. C57/BL6 male mice fed a diet moderately high in fat from coconut oil and soybean oil (SO-HFD, 40% kcal total fat) showed statistically significant increases in weight gain, adiposity, diabetes, glucose intolerance and insulin resistance compared to mice on a diet consisting primarily of coconut oil (HFD). They also had fatty livers with hepatocyte ballooning and very large lipid droplets as well as shorter colonic crypt length. While the high fructose diet (F-HFD) did not cause as much obesity or diabetes as SO-HFD, it did cause rectal prolapse and a very fatty liver, but no balloon injury. The coconut oil diet (with or without fructose) increased spleen weight while fructose in the presence of soybean oil increased kidney weight. Metabolomics analysis of the liver showed an increased accumulation of PUFAs and their metabolites as well as γ-tocopherol, but a decrease in cholesterol in SO-HFD. Liver transcriptomics analysis revealed a global dysregulation of cytochrome P450 (Cyp) genes in SO-HFD versus HFD livers, most notably in the Cyp3a and Cyp2c families. Other genes involved in obesity (e.g., Cidec, Cd36), diabetes (Igfbp1), inflammation (Cd63), mitochondrial function (Pdk4) and cancer (H19) were also upregulated by the soybean oil diet. Taken together, our results indicate that in mice a diet high in soybean oil is more detrimental to metabolic health than a diet high in fructose or coconut oil.

Induction of an altered lipid phenotype by two cancer promoting treatments in rat liver

Changes in lipid metabolism have been associated with tumor promotion in rat liver. Similarities and differences of lipid parameters were investigated using the mycotoxin fumonisin B1 (FB1) and the 2-acetylaminofluorene/partial hepatectomy (AAF/PH) treatments as cancer promoters in rat liver. A typical lipid phenotype was observed, including increased membranal phosphatidylethanolamine (PE) and cholesterol content, increased levels of C16:0 and monounsaturated fatty acids in PE and phosphatidylcholine (PC), as well as a decrease in C18:0 and long-chained polyunsaturated fatty acids in the PC fraction. The observed lipid changes, which likely resulted in changes in membrane structure and fluidity, may represent a growth stimulus exerted by the cancer promoters that could provide initiated cells with a selective growth advantage. This study provided insight into complex lipid profiles induced by two different cancer promoting treatments and their potential role in the development of hepatocyte nodules, which can be used to identify targets for the development of chemopreventive strategies against cancer promotion in the liver.

Fixed dose combination therapy loperamide and niacin ameliorates diethylnitrosamine-induced liver carcinogenesis in albino Wistar rats

Hepatocellular carcinoma (HCC) is among the most lethal cancers (five-year survival rates under 11%), which makes it the third most frequent cause of cancer related deaths in men and sixth in women.

Dietary PUFA and cancer

The aim of the present paper is to give a brief overview on the role of dietary fat in carcinogenesis and as possible anticancer agents. Dietary fat is an essential nutrient and important source for the essential fatty acids (FA), linoleic and α-linolenic acids, which contribute to proper growth and development. However, dietary fat has been associated with the development of colorectal, breast, prostate, endometrial and ovarian cancers, with the type and quality of fat playing an underlying role. Tumour growth is the disruption of the homoeostatic balance regulating cell differentiation, proliferation and apoptosis and is associated with altered lipid metabolism. Animal cancer models and human cancer biopsy tissue demonstrate that a characteristic lipid profile is associated with the growth and development of neoplastic lesions. This entails alterations in membrane cholesterol, phospholipid and PUFA metabolism. Particularly, alterations in cell membrane FA metabolism involving the n-6 and n-3 PUFA, are associated with changes in membrane structure, function, cellular oxidative status, activity of enzymes and signalling pathways. These events are a driving force in sustaining the altered growth of cancerous lesions and provide unique targets for intervention/cancer modulation. Challenges in utilising FA in cancer modulation exist regarding intake and effect on cell structure and biochemical interactions within the cell in the prevention of cancer development. Therefore, utilising dietary PUFA in a specific n-6:n-3 ratio may be an important chemopreventive tool in altering the growth characteristics of cancer cells.

Serum lipid profiling of patients with chronic hepatitis B, cirrhosis, and hepatocellular carcinoma by ultra fast LC/IT-TOF MS

In this study, an ultra fast LC/IT-TOF MS (UFLC/IT-TOF MS)-based serum lipidomics method was employed to characterize the serum lipid profile of patients with chronic hepatitis B, cirrhosis, and hepatocellular carcinoma (HCC). After data collection and processing, 96 lipids including lysophosphatidylcholines, phosphatidylcholines, sphingomyelins, triacylglycerides, and cholesterol esters were identified and used for subsequent data analysis. Partial least squares-discriminant analysis revealed that patients with liver diseases had distinctly different serum lipid profile from that of healthy controls; while cirrhosis and HCC patients had a similar serum lipid profile, but different from that of hepatitis patients. The ANOVA analysis found 75 of the 96 identified lipids to be abnormally regulated, among which most of these lipids were downregulated in cirrhosis and HCC patients compared with those of healthy controls and hepatitis patients, while hepatitis patients induced several lipids downregulated and others upregulated compared with those of healthy controls, indicating the aberrant lipid metabolism in patients with liver diseases. This work demonstrated the utility of UFLC/IT-TOF MS-based serum lipidomics as a powerful tool to investigate the lipid metabolism of liver diseases.

Mass spectrometry-based quantitative metabolomics revealed a distinct lipid profile in breast cancer patients

Breast cancer accounts for the largest number of newly diagnosed cases in female cancer patients. Although mammography is a powerful screening tool, about 20% of breast cancer cases cannot be detected by this method. New diagnostic biomarkers for breast cancer are necessary. Here, we used a mass spectrometry-based quantitative metabolomics method to analyze plasma samples from 55 breast cancer patients and 25 healthy controls. A number of 30 patients and 20 age-matched healthy controls were used as a training dataset to establish a diagnostic model and to identify potential biomarkers. The remaining samples were used as a validation dataset to evaluate the predictive accuracy for the established model. Distinct separation was obtained from an orthogonal partial least squares-discriminant analysis (OPLS-DA) model with good prediction accuracy. Based on this analysis, 39 differentiating metabolites were identified, including significantly lower levels of lysophosphatidylcholines and higher levels of sphingomyelins in the plasma samples obtained from breast cancer patients compared with healthy controls. Using logical regression, a diagnostic equation based on three metabolites (lysoPC a C16:0, PC ae C42:5 and PC aa C34:2) successfully differentiated breast cancer patients from healthy controls, with a sensitivity of 98.1% and a specificity of 96.0%.

Hepatocellular carcinoma patients with increased oxidative stress levels are prone to recurrence after curative treatment: a prospective case series study using the d-ROM test

PURPOSE

Oxidative stress plays an important role in liver carcinogenesis. To determine the impact of oxidative stress on the recurrence of stage I/II hepatocellular carcinoma (HCC) after curative treatment, we conducted a prospective case series analysis.

METHODS

This study included 45 consecutive patients with stage I/II HCC, who underwent curative treatment by surgical resection or radiofrequency ablation at Gifu Municipal Hospital from 2006 to 2007. In these 45 cases, recurrence-free survival was estimated using the Kaplan-Meier method. The factors contributing to HCC recurrence, including the serum levels of derivatives of reactive oxygen metabolites (d-ROM) as an index of oxidative stress, were subjected to univariate and multivariate analyses using the Cox proportional hazards model.

RESULTS

The serum levels of d-ROM (P = 0.0231), α-fetoprotein (AFP, P = 0.0274), and fasting plasma glucose (P = 0.0400) were significantly associated with HCC recurrence in the univariate analysis. Multivariate analysis showed that the serum levels of d-ROM (hazard ratio [HR] 1.0038, 95 % confidence interval [CI] 1.0002-1.0071, P = 0.0392) and AFP (HR 1.0002, 95 % CI 1.0000-1.0003, P = 0.0316) were independent predictors of HCC recurrence. Kaplan-Meier analysis showed that recurrence-free survival was low in patients with high serum d-ROM (≥570 Carr U, P = 0.0036) and serum AFP (≥40 ng/dL, P = 0.0185) levels.

CONCLUSIONS

The serum levels of d-ROM and AFP can be used for screening patients with a high risk for HCC recurrence. Patients who show increased levels of these factors require careful surveillance.

Lysophosphatidic acid aberrancies and hepatocellular carcinoma: studies in the MDR2 gene knockout mouse

Studies show that lysophosphatidic acid (LPA) reprogramming is associated with the development of hepatocellular carcinoma (HCC). This manuscript evaluates the MDR2(-/-) model of HCC as a tool to examine the role of LPA reprogramming in the initiation/progression of HCC and identify novel treatment targets. Hepatic tumors developed in MDR2(-/-) mice between 9-12 m and serum LPA levels were greater in MDR2(-/-) when compared to controls. Blocking LPA biosynthesis/signaling significantly reduced tumor burden. LPA biosynthesis/signaling plays an important role in murine MDR2(-/-) model and is potentially linked to regulation of TNFα or other cytokines that are relevant to high-risk patients.

Potential for statins in the chemoprevention and management of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a common, treatment-resistant malignancy with a complex molecular pathogenesis. Statins are a widely used class of cholesterol-lowering drugs with potential anticancer activity. We reviewed the evidence for a role of statins in primary and secondary chemoprevention of HCC and slowing the course of otherwise incurable primary or recurrent disease. A literature search (key words: Statins, hepatocellular carcinoma) conducted to this end, retrieved 119 references. Here we summarize the history, mechanism of action and cardiovascular use of statins and highlight that statins can affect several pathways implicated in the development of HCC. In vitro and animal studies provide strong evidence for a favorable effect of statins on HCC. However, evidence in humans is conflicting. We discuss in full detail the methodological strengths and pitfalls of published data including three cohort studies suggesting that the use of statins may protect from the development of HCC and of a single trial reporting increased survival in those with advanced HCC randomized to receive statins. A remarkably hepato-safe class of drugs acting on both hepatocyte and endothelial cells, statins also have potentially beneficial effects in lowering portal hypertension. In conclusion, there is strong experimental evidence that statins are beneficial in chemopreventing and slowing the growth of HCC. However, randomized controlled trials are necessary in order to investigate the role of statins in the chemoprevention of HCC and in slowing the course of otherwise incurable disease in humans.

Cellular and molecular mechanisms of hepatocellular carcinoma: an update

Hepatocellular carcinoma (HCC) is the most common primary malignant tumor that accounts for ~80 % of all liver cancer cases worldwide. It is a multifactorial disease caused by a variety of risk factors and often develops in the background of underlying cirrhosis. A number of cellular phenomena, such as tumor microenvironment, inflammation, oxidative stress, and hypoxia act in concert with various molecular events to facilitate tumor initiation, progression, and metastasis. The emergence of microRNAs and molecular-targeted therapies adds a new dimension in our efforts to combat this deadly disease. Intense research in this multitude of areas has led to significant progress in our understanding of cellular processes and molecular mechanisms that occur during multistage events that lead to hepatocarcinogenesis. In this review, we discuss the current knowledge of HCC, focusing mainly on advances that have occurred during the past 5 years and on the development of novel therapeutics for liver cancer.

Glutathione levels in human tumors

This review summarizes clinical studies in which glutathione was measured in tumor tissue from patients with brain, breast, gastrointestinal, gynecological, head and neck and lung cancer. Glutathione tends to be elevated in breast, ovarian, head and neck, and lung cancer and lower in brain and liver tumors compared to disease-free tissue. Cervical, colorectal, gastric, and esophageal cancers show both higher and lower levels of tumor glutathione. Some studies show an inverse relationship between patient survival and tumor glutathione. Based on this survey, we recommend approaches that may improve the clinical value of glutathione as a biomarker.

Preventive effect of Metformin against N-nitrosodiethylamine-initiated hepatocellular carcinoma in rats

Effect of Metformin in chemically induced hepatocarcinogenesis was assessed in Wistar rats. Intraperitoneal administration of chemical carcinogen diethyl nitrosamine (DENA) (200 mg/kg) in single dose elevated the levels of serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT), alkaline phosphatase (ALP), total cholesterol (TC), triglycerides (TG) and reduced high density lipoproteins (HDL), total proteins (TPR) and blood glucose level in tested animals. Histopathological examinations of the liver tissue showed marked carcinogenicity of the chemical carcinogen. Food and water intake, animal weights and serum albumin (ALB) were also assessed. The animals exposed to DENA showed a significant decrease in the body weights and, there were no significant alterations found in the total bilirubin (TBR) levels and gamma-glutamyltranspeptidase (GGTP), whereas the decreased levels of serum ALB were maintained by Metformin treatment. The elevated levels of serum SGOT, SGPT, ALP, AFP, TC and TG were restored by administration of Metformin in reduced dose (125 mg/kg) daily for 16 weeks p.o. Physiological and biochemical analysis showed the beneficial effects of Metformin in the animals exposed to DENA.

Disturbances in the glutathione/ophthalmate redox buffer system in the woodchuck model of hepatitis virus-induced hepatocellular carcinoma

Purpose. The incidence of liver tumors is rising in USA. The purpose of this study was to evaluate liver oxido-reductive status in the presence of chronic liver disease and hepatocellular carcinoma (HCC). Methods. Glutathione species and ophthalmate (OA) concentrations were measured by LC-MS in processed plasma and red blood cells (RBC) from infected Woodchuck with hepatitis virus (WHV). Blood samples were obtained from: (i) infected animals with tumors (WHV+/HCC+), (ii) infected animals without tumors (WHV+/HCC−) and (iii) healthy animals (WHC−/HCC−). Results. The concentration of reduced glutathione (GSH) and the ratio GSH/GSG were lower in plasma from WHV+/HCC+ animals when compared to WHV+/HCC− and WHV−/HCC− (P < 0.01). In contrast, the concentration of oxidized glutathione (GSSG) was found to be higher in plasma from WHV+/HCC+ animals when compared to WHV+/HCC− and WHV−/HCC− (P < 0.01). The Glutathione species and its ratio from the RBC compartment were similar among all groups. OA concentration in both plasma and RBC was significantly higher from WHV+/HCC+ when compared to WHV+/HCC− and WHV−/HCC− (P < 0.01). Conclusions. Disturbances of the glutathione redox buffer system and higher concentrations of OA were found in the WCV+/HCC+ animal model. The role of these compounds as biomarkers of early tumor development in patients with end stage liver disease remains to be determined.

Oxidative stress and antioxidants in hepatic pathogenesis

Long term hepatitis B virus (HBV) infection is a major risk factor in pathogenesis of chronic liver diseases, including hepatocellular carcinoma (HCC). The HBV encoded proteins, hepatitis B virus X protein and preS, appear to contribute importantly to the pathogenesis of HCC. Both are associated with oxidative stress, which can damage cellular molecules like lipids, proteins, and DNA during chronic infection. Chronic alcohol use is another important factor that contributes to oxidative stress in the liver. Previous studies reported that treatment with antioxidants, such as curcumin, silymarin, green tea, and vitamins C and E, can protect DNA from damage and regulate liver pathogenesis-related cascades by reducing reactive oxygen species. This review summarizes some of the relationships between oxidative stress and liver pathogenesis, focusing upon HBV and alcohol, and suggests antioxidant therapeutic approaches.

DNA double-strand breaks, potential targets for HBV integration

Hepatitis B virus (HBV)-induced hepatocellular carcinoma (HCC) is one of the most frequently occurring cancers. Hepadnaviral DNA integrations are considered to be essential agents which can promote the process of the hepatocarcinogenesis. More and more researches were designed to find the relationship of the two. In this study, we investigated whether HBV DNA integration occurred at sites of DNA double-strand breaks (DSBs), one of the most detrimental DNA damage. An 18-bp I-SceI homing endonuclease recognition site was introduced into the DNA of HepG2 cell line by stable DNA transfection, then cells were incubated in patients' serum with high HBV DNA copies and at the same time, DSBs were induced by transient expression of I-SceI after transfection of an I-SceI expression vector. By using nest PCR, the viral DNA was detected at the sites of the break. It appeared that integration occurred between part of HBVxgene and the I-SceI induced breaks. The results suggested that DSBs, as the DNA damages, may serve as potential targets for hepadnaviral DNA insertion and the integrants would lead to widespread host genome changes necessarily. It provided a new site to investigate the integration.