Vitamin E down-modulates iNOS and NADPH oxidase in c-Myc/TGF-alpha transgenic mouse model of liver cancer

Vitamins and fatty acids against chemotherapy-induced intestinal mucositis

Chemotherapy has allowed an increase in cancer survivorship, but it causes important adverse effects. Mucositis affecting the gastrointestinal tract is one of the main problems acutely caused by many antineoplastic drugs, such as 5-fluorouracil or methotrexate. Mucositis may cause pain, diarrhea, anorexia, weight loss, systemic infections and even death. This narrative review focuses on intestinal mucositis and the role that some nutraceuticals, namely vitamins (both lipid- and water-soluble) as well as fatty acids (FAs) and lipid-based products, can have in it. In preclinical (cell cultures, animal models) and/or human studies, vitamins A, D, E, B2, B9 and C, omega-3 long-chain FAs (eicosapentaenoic, docosahexaenoic, conjugated linoleic acid), short-chain FAs (mainly butyrate), medium-chain FAs (capric acid), and different lipid-based products (emu oil, extra-virgin olive oil, lipid replacement therapy), enriched in beneficial FAs and natural antioxidants, were shown to exert beneficial effects (both preventative and palliative) against chemotherapy-induced intestinal mucositis. Although the exact mechanisms of action involved in these effects are not yet well known, our review highlights the interest of investigating on diet and nutrition to implement scientifically robust strategies to improve protection of cancer patients against chemotherapy-induced adverse effects.

The altered metabolic pathways of diffuse large B-cell lymphoma not otherwise specified

Altered metabolic fingerprints of Diffuse large B-cell lymphoma, not otherwise specified (DLBCL NOS) may offer novel opportunities to identify new biomarkers and improve the understanding of its pathogenesis. This study aimed to investigate the modified metabolic pathways in extranodal, germinal center B-cell (GCB) and non-GCB DLBCL NOS from the head and neck. Formalin-fixed paraffin-embedded (FFPE) tissues from eleven DLBCL NOS classified according to Hans' algorithm using immunohistochemistry, and five normal lymphoid tissues (LT) were analyzed by high-performance liquid chromatography-mass spectrometry-based untargeted metabolomics. Partial Least Squares Discriminant Analysis showed that GCB and non-GCB DLBCL NOS have a distinct metabolomics profile, being the former more similar to normal lymphoid tissues. Metabolite pathway enrichment analysis indicated the following altered pathways: arachidonic acid, tyrosine, xenobiotics, vitamin E metabolism, and vitamin A. Our findings support that GCB and non-GCB DLBCL NOS has a distinct metabolomic profile, in which GCB possibly shares more metabolic similarities with LT than non-GCB DLBCL NOS.

Investigating Causal Associations of Diet-Derived Circulating Antioxidants with the Risk of Digestive System Cancers: A Mendelian Randomization Study

Molecular mechanisms and observational studies have found that diet-derived antioxidants are associated with digestive system cancers, whereas there is a lack of causal evidence from randomized clinical trials. In this study, we aimed to assess the causality of these associations through a Mendelian randomization (MR) study. Single nucleotide polymorphisms of diet-derived circulating antioxidants (i.e., α- and γ-tocopherol, ascorbate, retinol, β-carotene, lycopene, and urate), accessed by absolute levels and relative metabolite concentrations, were used as genetic instruments. Summary statistics for digestive system cancers were obtained from the UK Biobank and FinnGen studies. Two-sample MR analyses were performed in each of the two outcome databases, followed by a meta-analysis. The inverse-variance weighted MR was adopted as the primary analysis. Five additional MR methods (likelihood-based MR, MR-Egger, weighted median, penalized weighted median, and MR-PRESSO) and replicate MR analyses for outcomes from different sources were used as sensitivity analyses. Genetically determined antioxidants were not significantly associated with five digestive system cancers, after correcting for multiple tests. However, we found suggestive evidence that absolute ascorbate levels were negatively associated with colon cancer in UK Biobank-the odds ratio (OR) per unit increase in ascorbate was 0.774 (95% confidence interval [CI] 0.608-0.985, p = 0.037), which was consistent with the results in FinnGen, and the combined OR was 0.764 (95% CI 0.623-0.936, p = 0.010). Likewise, higher absolute retinol levels suggestively reduced the pancreatic cancer risk in FinnGen-the OR per 10% unit increase in ln-transformed retinol was 0.705 (95% CI 0.529-0.940, p = 0.017), which was consistent with the results in UK Biobank and the combined OR was 0.747 (95% CI, 0.584-0.955, p = 0.020). Sensitivity analyses verified the above suggestive evidence. Our findings suggest that higher levels of antioxidants are unlikely to be a causal protective factor for most digestive system cancers, except for the suggestive protective effects of ascorbate on colon cancer and of retinol on pancreatic cancer.

Hepatic Insulin Resistance in Hyperthyroid Rat Liver: Vitamin E Supplementation Highlights a Possible Role of ROS

Thyroid hormones are normally involved in glycaemic control, but their excess can lead to altered glucose metabolism and insulin resistance (IR). Since hyperthyroidism-linked increase in ROS results in tissue oxidative stress that is considered a hallmark of conditions leading to IR, it is conceivable a role of ROS in the onset of IR in hyperthyroidism. To verify this hypothesis, we evaluated the effects of vitamin E on thyroid hormone-induced oxidative damage, insulin resistance, and on gene expression of key molecules involved in IR in the rat liver. The factors involved in oxidative damage, namely the total content of ROS, the mitochondrial production of ROS, the activity of antioxidant enzymes, the in vitro susceptibility to oxidative stress, have been correlated to insulin resistance indices, such as insulin activation of hepatic Akt and plasma level of glucose, insulin and HOMA index. Our results indicate that increased levels of oxidative damage ROS content and production and susceptibility to oxidative damage, parallel increased fasting plasma level of glucose and insulin, reduced activation of Akt and increased activation of JNK. This last result suggests a role for JNK in the insulin resistance induced by hyperthyroidism. Furthermore, the variation of the genes Pparg, Ppara, Cd36 and Slc2a2 could explain, at least in part, the observed metabolic phenotypes.

Molecular relation between biological stress and carcinogenesis

This paper aims to overview different types of stress, including DNA replication stress, oxidative stress, and psychological stress. Understanding the processes that constitute a cellular response to varied types of stress lets us find differences in how normal cells and cancer cells react to the appearance of a particular kind of stressor. The revealed dissimilarities are the key for targeting new molecules and signaling pathways in anticancer treatment. For this reason, molecular mechanisms that underlay DNA replication stress, oxidative stress, and psychological stress have been studied and briefly presented to indicate biochemical points that make stressors contribute to cancer development. What is more, the viewpoint in which cancer constitutes the outcome and the cause of stress has been taken into consideration. In a described way, this paper draws attention to the problem of cancer-related post-traumatic stress disorder and proposes a novel, multidimensional oncological approach, connecting anticancer treatment with psychiatric support.

Redox-sensitive signaling pathways in renal cell carcinoma

Renal cell carcinoma (RCC) is one of the most lethal urological cancers, highly resistant to chemo and radiotherapy. Obesity and smoking are the best-known risk factors of RCC, both related to oxidative stress presence, suggesting a significant role in RCC development and maintenance. Surgical resection is the treatment of choice for localized RCC; however, this neoplasia is hardly diagnosable at its initial stages, occurring commonly in late phases and even when metastasis is already present. Systemic therapies are the option against RCC in these more advanced stages, such as cytokine therapy or a combination of tyrosine kinase inhibitors with immunotherapies; nevertheless, these strategies are still insufficient. A field poorly analyzed in this neoplasia is the status of cell signaling pathways sensible to the redox state, which have been associated with the development and maintenance of RCC. This review focuses on alterations reported in the following redox-sensitive molecules and signaling pathways in RCC: mitogen-activated protein kinases, protein kinase B (AKT)/tuberous sclerosis complex 2/mammalian target of rapamycin C1, AKT/glycogen synthase kinase 3/β-catenin, nuclear factor κB/inhibitor of κB/epidermal growth factor receptor, and protein kinase Cζ/cut-like homeodomain protein/factor inhibiting hypoxia-inducible factor (HIF)/HIF as potential targets for redox therapy.

Role of vitamin E in the treatment of non-alcoholic steatohepatitis

Non-alcoholic steatohepatitis (NASH), a severe form of non-alcoholic fatty liver disease (NAFLD), can progress to cirrhosis, hepatocellular carcinoma (HCC), and hepatic failure/liver transplantation. Indeed, NASH will soon be the leading cause of HCC and liver transplantation. Lifestyle intervention represents the cornerstone of NASH treatment, but it is difficult to sustain. However, no pharmacotherapies for NASH have been approved. Oxidative stress has been implicated as one of the key factors in the pathogenesis of NASH. Systematic reviews with meta-analyses have confirmed that vitamin E reduces transaminase activities and may resolve NASH histopathology without improving hepatic fibrosis. However, vitamin E is not recommended for the treatment of NASH in diabetes, NAFLD without liver biopsy, NASH cirrhosis, or cryptogenic cirrhosis. Nevertheless, vitamin E supplementation may improve clinical outcomes in patients with NASH and bridging fibrosis or cirrhosis. Further studies are warranted to confirm such effects of vitamin E and that it would reduce overall mortality/morbidity without increasing the incidence of cardiovascular events. Future clinical trials of the use of vitamin E in combination with other anti-fibrotic agents may demonstrate an additive or synergistic therapeutic effect. Vitamin E is the first-line pharmacotherapy for NASH, according to the consensus of global academic societies.

Vitamins and non-alcoholic fatty liver disease: A Molecular Insight⋆

The incidence of non-alcoholic fatty liver disease (NAFLD) is rising rapidly across the globe. NAFLD pathogenesis is largely driven by an imbalance in hepatic energy metabolism and at present, there is no approved drug for its treatment. The liver plays a crucial role in micronutrient metabolism and deregulation of this micronutrient metabolism may contribute to the pathogenesis of NAFLD. Vitamins regulate several enzymatic processes in the liver, and derangement in vitamin metabolism is believed to play a critical role in NAFLD progression. The anti-oxidant activities of vitamin C and E have been attributed to mitigate hepatocyte injury, and alterations in the serum levels of vitamin D, vitamin B12 and folate have shown a strong correlation with NAFLD severity. This review aims to highlight the role of these vitamins, which represent promising therapeutic targets for the management of NAFLD.

Remodeling of Mitochondrial Plasticity: The Key Switch from NAFLD/NASH to HCC

Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver and the third-leading cause of cancer-related mortality. Currently, the global burden of nonalcoholic fatty liver disease (NAFLD) has dramatically overcome both viral and alcohol hepatitis, thus becoming the main cause of HCC incidence. NAFLD pathogenesis is severely influenced by lifestyle and genetic predisposition. Mitochondria are highly dynamic organelles that may adapt in response to environment, genetics and epigenetics in the liver ("mitochondrial plasticity"). Mounting evidence highlights that mitochondrial dysfunction due to loss of mitochondrial flexibility may arise before overt NAFLD, and from the early stages of liver injury. Mitochondrial failure promotes not only hepatocellular damage, but also release signals (mito-DAMPs), which trigger inflammation and fibrosis, generating an adverse microenvironment in which several hepatocytes select anti-apoptotic programs and mutations that may allow survival and proliferation. Furthermore, one of the key events in malignant hepatocytes is represented by the remodeling of glucidic-lipidic metabolism combined with the reprogramming of mitochondrial functions, optimized to deal with energy demand. In sum, this review will discuss how mitochondrial defects may be translated into causative explanations of NAFLD-driven HCC, emphasizing future directions for research and for the development of potential preventive or curative strategies.

Vitamin E and 5-amino salicylic acid ameliorates acrylamide-induced peripheral neuropathy by inhibiting caspase-3 and inducible nitric oxide synthase immunoexpression

Acrylamide is a fundamental cause of accidental toxicity in humans. This study aimed to investigate the neuroprotective effect of vitamin E (Vit. E), 5-amino salicylic acid (5-ASA), and their combination against acrylamide-induced sciatic nerve toxicity. For this purpose, 25 male Wister rats were divided into 5 groups: control, acrylamide, acrylamide + Vit. E, acrylamide + 5-ASA, and acrylamide + Vit. E + 5-ASA. Food intake and body weight were assessed after 7 days. Furthermore, the gait score was also evaluated for each rat. The sciatic nerve was dissected, fixed, and processed for routine light and electron microscopic examination. Haematoxylin and eosin, osmium tetroxide for myelin sheath, and toluidine blue for semithin section were used. In addition, immunohistochemistry for caspase-3 and inducible nitric oxide synthase (iNOS) were performed. The results showed reduced food intake and body weight in acrylamide rats. Abnormal gait score was also recorded in acrylamide rats with significant improvement in Vit. E, and Vit. E + 5-ASA groups. Histologically, Vit. E and 5-ASA provided potential protection against decreased sciatic nerve axon density, disrupted myelination, and the alteration in the immunohistochemistry induced by acrylamide. Vit. E and its combination with 5-ASA provided more evident protection compared to 5-ASA alone. 5-ASA significantly decreased apoptotic cell death (caspase-3 immunoexpression) while Vit. E failed. Both Vit. E and 5-ASA significantly decreased iNOS immunoexpression in the sciatic nerve, where 5-ASA was superior to Vit. E. These findings concluded that both Vit. E and 5-ASA protect against acrylamide-induced peripheral neuropathy through downregulation of both caspase-3 and iNOS immunoexpression.

Human Papillomavirus-related Cancers and Mitochondria

Although it has been established that persistent infection with high risk human papillomavirus (HR-HPV) is the main cause in the development of cervical cancer, the HR-HPV infection is also related with the cause of a significant fraction of other human malignancies from the mucosal squamous epithelial such as anus, vagina, vulva, penis and oropharynx. HR-HPV infection induces cell proliferation, cell death evasion and genomic instability resulting in cell transformation, due to HPV proteins, which target and modify the function of differents cell molecules and organelles, such as mitochondria. Mitochondria are essential in the production of the cellular energy by oxidative phosphorylation (OXPHOS), in the metabolism of nucleotides, aminoacids (aa), and fatty acids, even in the regulation of cell death processes such as apoptosis or mitophagy. Thus, mitochondria have a significant role in the HPV-related cancer development. This review focuses on the role of HPV and mitochondria in HPV-related cancer development, and treatments associated to mitochondrial apoptosis.

Cytoskeletal Proteins in Cancer and Intracellular Stress: A Therapeutic Perspective

Cytoskeletal proteins, which consist of different sub-families of proteins including microtubules, actin and intermediate filaments, are essential for survival and cellular processes in both normal as well as cancer cells. However, in cancer cells, these mechanisms can be altered to promote tumour development and progression, whereby the functions of cytoskeletal proteins are co-opted to facilitate increased migrative and invasive capabilities, proliferation, as well as resistance to cellular and environmental stresses. Herein, we discuss the cytoskeletal responses to important intracellular stresses (such as mitochondrial, endoplasmic reticulum and oxidative stresses), and delineate the consequences of these responses, including effects on oncogenic signalling. In addition, we elaborate how the cytoskeleton and its associated molecules present themselves as therapeutic targets. The potential and limitations of targeting new classes of cytoskeletal proteins are also explored, in the context of developing novel strategies that impact cancer progression.

Mitochondrial Dysfunction in the Transition from NASH to HCC

The liver constantly adapts to meet energy requirements of the whole body. Despite its remarkable adaptative capacity, prolonged exposure of liver cells to harmful environmental cues (such as diets rich in fat, sugar, and cholesterol) results in the development of chronic liver diseases (including non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH)) that can progress to hepatocellular carcinoma (HCC). The pathogenesis of these diseases is extremely complex, multifactorial, and poorly understood. Emerging evidence suggests that mitochondrial dysfunction or maladaptation contributes to detrimental effects on hepatocyte bioenergetics, reactive oxygen species (ROS) homeostasis, endoplasmic reticulum (ER) stress, inflammation, and cell death leading to NASH and HCC. The present review highlights the potential contribution of altered mitochondria function to NASH-related HCC and discusses how agents targeting this organelle could provide interesting treatment strategies for these diseases.

Therapeutic effect of Vitamin E in preventing bone loss: An evidence-based review

The present review explored the anti-inflammatory and immunomodulatory properties of vitamin E, which has protective action against osteoporosis. A systematic review of the literature was conducted to identify the published bone studies on vitamin E. The studies included inflammatory or immunology-related parameters. Medline and Scopus databases were searched for relevant studies published from 2005 till 2015. Research articles published in English and confined to the effect of vitamin E on bone were included. It is pertinent to mention that these studies took into consideration inflammatory or immunology parameters including interleukin (IL)-1, IL-6, receptor activator of nuclear factor kappa-B ligand (RANKL), inducible nitric oxide synthases (iNOS), serum amyloid A (SAA), e-selection and high-sensitivity C-reactive protein (hs-CRP). An extended literature search yielded 127 potentially relevant articles with seven articles meeting the inclusion and exclusion criteria. Another recent article was added with the total number accounting to eight. All these included literature comprised five animal studies, one in-vitro study and two human studies. These studies demonstrated that vitamin E, especially tocotrienol, was able to alleviate IL-1, IL-6, RANKL, iNOS and hs-CRP levels in relation to bone metabolism. In conclusion, vitamin E exerts its anti-osteoporotic actions via its anti-inflammatory and immunomodulatory effects.

Prognostic relevance of miR-137 and its liver microenvironment regulatory target gene AFM in hepatocellular carcinoma

MiR-137 has been identified as potential hepatocellular carcinoma (HCC) prognostic biomarkers. Highly relevant HCC prognostic biomarkers may be derived from combinations of miR-137 with its target genes involved in the regulation of liver microenvironment. This study aimed at the discovery of such a combination with improved HCC prognosis performance than miR-137 or its target gene alone in a significantly higher number of HCC patients than previous studies. Analysis of the differentially expressed micro RNAs (miRNAs) between cancer and noncancer tissues reconfirmed miR-137 to be among the most relevant prognostic miRNAs and the data of 375 HCC patients and 50 normal cases were from the Cancer Genome Atlas (TCGA) data sets. Target genes were identified by the established search methods and Kaplan-Meier survival analysis of HCC patients was used to evaluate the overall survival (OS) and recurrence-free survival (RFS). Cox proportional hazards regression indicated that the miR-137 and its target gene AFM combination is an independent prognostic factor for the OS and RFS in HCC. In vitro experiments validated that miR-137 could bind to 3'-untranslated region of the AFM and promote the invasion and metastasis of HCC cell lines. The expressions of miR-137 and its liver microenvironment regulatory target gene AFM in combination significantly correlated with HCC progression in a higher number of patients than in previous studies, which suggested their potential as prognostic biomarkers for HCC.

The Role of Vitamin E in the Treatment of NAFLD

There has been a growing interest in the role of vitamin E supplementation in the treatment and/or prevention of nonalcoholic fatty liver (NAFLD). We performed a systematic review of the medical literature from inception through 15 June 2018 by utilizing PubMed and searching for key terms such as NAFLD, vitamin E, alpha-tocopherol, and nonalcoholic steatohepatitis (NASH). Data from studies and medical literature focusing on the role of vitamin E therapy in patients with NAFLD and nonalcoholic steatohepatitis (NASH) were reviewed. Most studies assessing the impact of vitamin E in NAFLD were designed to evaluate patients with NASH with documented biochemical and histological abnormalities. These studies demonstrated improvement in biochemical profiles, with a decline in or normalization of liver enzymes. Furthermore, histological assessment showed favorable outcomes in lobular inflammation and hepatic steatosis following treatment with vitamin E. Current guidelines regarding the use of vitamin E in the setting of NAFLD recommend that vitamin E-based treatment be restricted to biopsy-proven nondiabetic patients with NASH only. However, some concerns have been raised regarding the use of vitamin E in patients with NASH due to its adverse effects profile and lack of significant improvement in hepatic fibrosis. In conclusion, the antioxidant, anti-inflammatory, and anti-apoptotic properties of vitamin E accompanied by ease-of-use and exceptional tolerability have made vitamin E a pragmatic therapeutic choice in non-diabetic patients with histologic evidence of NASH. Future clinical trials with study design to assess vitamin E in combination with other anti-fibrotic agents may yield an additive or synergistic therapeutic effect.

Beneficial and Paradoxical Roles of Anti-Oxidative Nutritional Support for Non-Alcoholic Fatty Liver Disease

Oxidative stress is being recognized as a key factor in the progression of chronic liver disease (CLD), especially non-alcoholic fatty liver disease (NAFLD). Many NAFLD treatment guidelines recommend the use of antioxidants, especially vitamin E. Many prospective studies have described the beneficial effects of such agents for the clinical course of NAFLD. However, as these studies are usually short-term evaluations, lasting only a few years, whether or not antioxidants continue to exert favorable long-term effects, including in cases of concomitant hepatocellular carcinoma, remains unclear. Antioxidants are generally believed to be beneficial for human health and are often commercially available as health-food products. Patients with lifestyle-related diseases often use such products to try to be healthier without practicing lifestyle intervention. However, under some experimental NAFLD conditions, antioxidants have been shown to encourage the progression of hepatocellular carcinoma, as oxidative stress is toxic for cancer cells, just as for normal cells. In this review, we will highlight the paradoxical effects of antioxidants against NAFLD and related hepatocellular carcinoma.

Anti-inflammatory and antitumor action of hydrogen via reactive oxygen species

Hydrogen (H₂) has advantages that lead it to be used as a novel antioxidant in preventive and therapeutic applications. H₂ can permeate into biomembranes, cytosol, mitochondria and nuclei, and can be dissolved in water or saline to produce H₂ water or H₂-rich saline. H₂ selectively reduces oxidants of the detrimental reactive oxygen species (ROS), including hydroxyl radicals (·OH) and peroxynitrite (ONOO^-), which serve a causative role in the promotion of tumor cell proliferation, invasion and metastasis, but do not disturb metabolic oxidation-reduction reactions in cell signaling. Compared with traditional antioxidants, H₂ is a small molecule that can easily dissipate throughout the body and cells; thus, it may be a safe and effective antioxidant for inflammatory diseases and cancer, since ROS usually initiates tumor progression. Treatment with H₂ may involve correction of the oxidative/anti-oxidative imbalance and suppression of inflammatory mediators. Therefore the present review will discuss the anti-inflammatory and anti-tumorigenic action of H₂ via ROS.

Crosstalk Between Peroxisome Proliferator-Activated Receptor Gamma and the Canonical WNT/β-Catenin Pathway in Chronic Inflammation and Oxidative Stress During Carcinogenesis

Inflammation and oxidative stress are common and co-substantial pathological processes accompanying, promoting, and even initiating numerous cancers. The canonical WNT/β-catenin pathway and peroxisome proliferator-activated receptor gamma (PPARγ) generally work in opposition. If one of them is upregulated, the other one is downregulated and vice versa. WNT/β-catenin signaling is upregulated in inflammatory processes and oxidative stress and in many cancers, although there are some exceptions for cancers. The opposite is observed with PPARγ, which is generally downregulated during inflammation and oxidative stress and in many cancers. This helps to explain in part the opposite and unidirectional profile of the canonical WNT/β-catenin signaling and PPARγ in these three frequent and morbid processes that potentiate each other and create a vicious circle. Many intracellular pathways commonly involved downstream will help maintain and amplify inflammation, oxidative stress, and cancer. Thus, many WNT/β-catenin target genes such as c-Myc, cyclin D1, and HIF-1α are involved in the development of cancers. Nuclear factor-kappaB (NFκB) can activate many inflammatory factors such as TNF-α, TGF-β, interleukin-6 (IL-6), IL-8, MMP, vascular endothelial growth factor, COX2, Bcl2, and inducible nitric oxide synthase. These factors are often associated with cancerous processes and may even promote them. Reactive oxygen species (ROS), generated by cellular alterations, stimulate the production of inflammatory factors such as NFκB, signal transducer and activator transcription, activator protein-1, and HIF-α. NFκB inhibits glycogen synthase kinase-3β (GSK-3β) and therefore activates the canonical WNT pathway. ROS activates the phosphatidylinositol 3 kinase/protein kinase B (PI3K/Akt) signaling in many cancers. PI3K/Akt also inhibits GSK-3β. Many gene mutations of the canonical WNT/β-catenin pathway giving rise to cancers have been reported (CTNNB1, AXIN, APC). Conversely, a significant reduction in the expression of PPARγ has been observed in many cancers. Moreover, PPARγ agonists promote cell cycle arrest, cell differentiation, and apoptosis and reduce inflammation, angiogenesis, oxidative stress, cell proliferation, invasion, and cell migration. All these complex and opposing interactions between the canonical WNT/β-catenin pathway and PPARγ appear to be fairly common in inflammation, oxidative stress, and cancers.

Short-term vitamin E treatment impairs reactive oxygen species signaling required for adipose tissue expansion, resulting in fatty liver and insulin resistance in obese mice

Objectives

The use of antioxidant therapy in the treatment of oxidative stress-related diseases such as cardiovascular disease, diabetes or obesity remains controversial. Our aim is to demonstrate that antioxidant supplementation may promote negative effects if used before the establishment of oxidative stress due to a reduced ROS generation under physiological levels, in a mice model of obesity.

Methods

C57BL/6J mice were fed with a high-fat diet for 14 weeks, with (OE group) or without (O group) vitamin E supplementation.

Results

O mice developed a mild degree of obesity, which was not enough to induce metabolic alterations or oxidative stress. These animals exhibited a healthy expansion of retroperitoneal white adipose tissue (rpWAT) and the liver showed no signs of lipotoxicity. Interestingly, despite achieving a similar body weight, OE mice were insulin resistant. In the rpWAT they presented a reduced generation of ROS, even below physiological levels (C: 1651.0 ± 212.0; O: 3113 ± 284.7; OE: 917.6 ±104.4 RFU/mg protein. C vs OE p< 0.01). ROS decay may impair their action as second messengers, which could account for the reduced adipocyte differentiation, lipid transport and adipogenesis compared to the O group. Together, these processes limited the expansion of this fat pad and as a consequence, lipid flux shifted towards the liver, causing steatosis and hepatomegaly, which may contribute to the marked insulin resistance.

Conclusions

This study provides in vivo evidence for the role of ROS as second messengers in adipogenesis, lipid metabolism and insulin signaling. Reducing ROS generation below physiological levels when the oxidative process has not yet been established may be the cause of the controversial results obtained by antioxidant therapy.

Gene expression of NOX family members and their clinical significance in hepatocellular carcinoma

Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex-derived reactive oxygen species (ROS) promote chronic liver inflammation and remodeling that can drive hepatocellular carcinoma development. The role of NOX expression in hepatocellular carcinoma (HCC) has been partially investigated; however, the clinical relevance of collective or individual NOX family member expression for HCC survival remains unclear. Here, we obtained NOX mRNA expression data for 377 HCC samples and 21 normal liver controls from the TCGA data portal and performed Kaplan-Meier survival, gene ontology functional enrichment, and gene set enrichment analyses. Although most NOX genes exhibited little change, some were significantly induced in HCC compared to that in normal controls. In addition, HCC survival analyses indicated better overall survival in patients with high NOX4 and DUOX1 expression, whereas patients with high NOX1/2/5 expression showed poor prognoses. Gene-neighbour and gene set enrichment analyses revealed that NOX1/2/5 were strongly correlated with genes associated with cancer cell survival and metastasis, whereas increased NOX4 and DUOX1 expression was associated with genes that inhibit tumour progression. On the basis of these data, NOX family gene expression analysis could be a predictor of survival and identify putative therapeutic targets in HCC.

HO‑1 alleviates cholesterol‑induced oxidative stress through activation of Nrf2/ERK and inhibition of PI3K/AKT pathways in endothelial cells

Heme oxygenase‑1 (HO‑1), as an inducible and cytoprotective enzyme, has a protective effect against cellular oxidative stress. In the present study, cholesterol was used to induce lipid overload and increase reactive oxygen species (ROS), leading to oxidative stress in EA.hy926 cells. In the present study, western blotting and immunofluorescence analysis were used to detect the expression level of important molecules in the metabolism process of cholesterol. It was confirmed that cholesterol stimulation upregulated the expression of HO‑1 in a time‑dependent manner via the activation and translocation of nuclear factor erythroid 2‑related factor 2 (Nrf2), activation of the mitogen‑activated protein kinase (MAPK)/extracellular signal‑regulated kinase (ERK) signaling pathway and increasing intercellular Ca2+ ([Ca2+]i) concentration. The results showed that increasing the expression of HO‑1 decreased activation of the phosphoinositide 3‑kinase (PI3K)/AKT signaling pathway and inhibited the expression of c‑Myc. It was confirmed that cholesterol‑mediated oxidative damage in vascular endothelial cells induced an increase in the expression of HO‑1 via the activation of Nrf2 and the MAPK/ERK signaling pathway, and increasing the [Ca2+]i concentration. The overexpression of HO‑1 alleviated oxidative damage through inhibition of the PI3K/AKT signaling pathway and downregulation of the expression of c‑Myc.

Alleviation of 5-fluorouracil-induced intestinal mucositis in rats by vitamin E via targeting oxidative stress and inflammatory markers

BackgroundIntestinal mucositis is a major concern related with cancer therapy. It is well established that overproduction of reactive oxygen species and inflammatory mediators plays vital role in the pathogenesis of mucositis. The aim of the study was to investigate the modulatory effect of vitamin E (vit. E) on 5-fluorouracil (5-FU)-induced intestinal mucositis by targeting oxidative stress and inflammatory markers in rats. MethodsRats were randomly divided into four groups of six animals each. All four-group animals received normal standard diet and water throughout the experimental period which last up to 10 days. Rats were gavaged with vit. E (300 mg/kg b. wt.) daily for 10 days (day 1-10) and were given intraperitoneal injection of 5-FU (150 mg/kg b. wt.) or saline (control) on day 8 to induce mucositis. Results We found that vit. E supplementation ameliorated 5-FU-induced lipid peroxidation, myeloperoxidase activity, activation of nuclear factor κB, expression of cyclooxygenase-2, inducible nitric oxide synthase and mucin depletion. Vit. E administration also attenuated 5-FU-induced histological anomalies such as neutrophil infiltration, loss of cellular integrity, villus and crypt deformities. ConclusionsFindings of the study suggest that vit. E inhibits 5-FU-induced mucositis via modulation of oxidative stress, activation of redox sensitive transcription factor and its downstream targets.

Effect of vitamin E on oxidative stress level in blood, synovial fluid, and synovial tissue in severe knee osteoarthritis: a randomized controlled study

Background

This study was performed to evaluate the antioxidative and anti-inflammatory effects of vitamin E on oxidative stress in the plasma, synovial fluid, and synovial tissue of patients with knee osteoarthritis.

Methods

Seventy-two patients with late-stage knee osteoarthritis scheduled for total knee arthroplasty were randomized to take oral placebo (Group A) or 400 IU of vitamin E (Group B) once a day for 2 months before undergoing surgery. The blood levels of endpoints indicating oxidative stress or antioxidant capacity, Knee Society Score (KSS), Western Ontario and McMaster Universities Osteoarthritis Index score (WOMAC), and adverse effects were compared before and after the intervention between the two groups. At surgery, these redox endpoints and histological findings were compared between the synovial fluid and synovial tissue.

Results

In blood samples, the pre-intervention of oxidative stress and antioxidative capacity were not different between Group A and Group B. In post-intervention blood samples, the Malondialdehyde (Group A 1.34 ± 0.10, Group B 1.00 ± 0.09, p < 0.02), Alpha tocopherol (Group A 15.92 ± 1.08, Group B 24.65 ± 1.47, p < 0.01) and Trolox equivalent antioxidant capacity (Group A 4.22 ± 0.10, Group B 5.04 ± 0.10, 0 < 0.01) were significantly different between Group A and Group B. In synovial fluid samples, the Malondialdehyde (Group A 1.42 ± 0.12, Group B 1.06 ± 1.08, p 0.01), Alphatocopherol (Group A 4.51, Group B 7.03, p < 0.01), Trolox equivalent antioxidant capacity (Group A, 1.89 ± 0.06, Group B 2.19 ± 0.10) were significantly different between Group A and Group B. The pre-intervention WOMAC score and KSS score were not different between Group A and Group B. The post-intervention WOMAC score was significantly improved in all categories in Group B (Pain: Group A 27.26 ± 0.89, Group B 19.19 ± 1.43, p < 0.01; Stiffness: Group A 8.23 ± 0.79, Group B 5.45 ± 0.73, p 0.01; Function: Group A 94.77 ± 4.22, Group B 72.74 ± 6.55, p < 0.01). The post-intervention KSS score was significantly improved in all categories in Group B (Clinical: Group A 25.31 ± 14.33, Group B 33.52 ± 16.96, p < 0.01; Functional: Group A 41.43 ± 16.11, Group B 51.61 ± 19.60, p 0.02). Significantly fewer synovial tissue cells were stained with nitrotyrosine and hematoxylin–eosin in Group B than in Group A. There were no differences in adverse effects or surgical complications between the groups.

Conclusion

Vitamin E is an effective antioxidant that can improve clinical symptoms and reduce oxidative stress conditions in patients with late-stage knee osteoarthritis.

Trial registration

This research project had been approved for registration at Thai Clinical Trials Registry (TCTR) since 2016–08-28 11:26:32 (Retrospective registered). The TCTR identification number is TCTR20160828001.

Clinicopathological characteristics of non-B non-C hepatocellular carcinoma without past hepatitis B virus infection

AIM

Past hepatitis B virus (HBV) infection is considered a risk factor for hepatocarcinogenesis, but the clinicopathological characteristics of non-B non-C hepatocellular carcinoma (NBNC-HCC) excluding past HBV infection have not been investigated. This study aimed to clarify the clinicopathological features of strictly defined NBNC-HCC.

METHODS

Among HCC patients who underwent surgical resection at our affiliated hospitals in Nagano prefecture, Japan, between 1996 and 2012, 77 were negative for serum anti-HBV core/surface antibodies in addition to HBV surface antigen and anti-hepatitis C virus antibody without signs of autoimmune liver disease, Wilson disease, or hemochromatosis. These patients were divided into the alcohol intake-positive group (ethanol intake >20 g/day, n = 31), non-alcoholic fatty liver group (steatosis >5% and ethanol intake <20 g/day, n = 30), and cryptogenic group (no ethanol intake or steatosis, n = 16). Preoperative clinical parameters, tumor and background liver pathology, and prognosis were analyzed.

RESULTS

Advanced fibrosis and steatosis were detected in 64% and 60% of all patients, respectively. Approximately 85% of the alcohol intake-positive patients had advanced fibrosis. Non-alcoholic fatty liver HCC subjects had the highest body mass index and prevalence of diabetes, but 30-40% had none to mild fibrosis. The cryptogenic group of HCC patients had the lowest incidence of accompanying hepatic inflammation/fibrosis but the largest tumor size. Recurrence/survival rates were comparable among the groups.

CONCLUSIONS

Liver fibrosis and steatosis are risk factors of HCC regardless of past HBV infection and ethanol consumption. The present results also indicate the possibility of hepatocarcinogenesis independent of hepatic steatosis, inflammation and fibrosis, ethanol intake, and past HBV infection.

Redox proteomics screening cellular factors associated with oxidative stress in hepatocarcinogenesis

Liver cancer is a major global health problem being the sixth most common cancer and the third cause of cancer-related death, with hepatocellular carcinoma (HCC) representing more than 90% of primary liver cancers. Mounting evidence suggests that, compared with their normal counterparts, many types of cancer cell have increased levels of ROS. Therefore, cancer cells need to combat high levels of ROS, especially at early stages of tumor development. Recent studies have revealed that ROS-mediated regulation of redox-sensitive proteins (redox sensors) is involved in the pathogenesis and/or progression of many human diseases, including cancer. Unraveling the altered functions of redox sensors and the underlying mechanisms in hepatocarcinogenesis is critical for the development of novel cancer therapeutics. For this reason, redox proteomics has been developed for the high-throughput screening of redox sensors, which will benefit the development of novel therapeutic strategies for the treatment of HCC. In this review, we will briefly introduce several novel redox proteomics techniques that are currently available to study various oxidative modifications in hepatocarcinogenesis and summarize the most important discoveries in the study of redox processes related to the development and progression of HCC.

Gamma-tocotrienol treatment increased peroxiredoxin-4 expression in HepG2 liver cancer cell line

Background

To determine the antiproliferative effect of gamma-tocotrienol (GTT) treatment on differential protein expression in HepG2 cells.

Methods

HepG2 cells were treated with 70 μM GTT for 48 hours and differentially expressed protein spots were determined by two-dimensional electrophoresis (2DE), identified by MALDI-TOF mass spectrometer (MS) and validated by quantitative real-time polymerase chain reaction (qRT-PCR).

Results

GTT treatment on HepG2 cells showed a total of five differentially expressed proteins when compared to their respective untreated cells where three proteins were down-regulated and two proteins were up-regulated. One of these upregulated proteins was identified as peroxiredoxin-4 (Prx4). Validation by qRT-PCR however showed decreased expression of Prx4 mRNA in HepG2 cells following GTT treatment.

Conclusions

GTT might directly influence the expression dynamics of peroxiredoxin-4 to control proliferation in liver cancer.

Oleuropein induces apoptosis via activation of caspases and suppression of phosphatidylinositol 3-kinase/protein kinase B pathway in HepG2 human hepatoma cell line

Oleuropein is a polyphenol, that is found in extra‑virgin olive oil. Previous studies have shown that oleuropein inhibits cell proliferation and induces apoptosis in breast cancer, colorectal cancer and thyroid cancer. The aim of the present study was to investigate the effects of oleuropein in hepatocellular carcinoma (HCC) cells. The results of Cell Counting Kit 8 and flow cytometric analysis indicated that oleuropein effectively inhibited cell viability and induced apoptosis in HepG2 human hepatoma cells in a dose‑dependent manner, through activation of the caspase pathway. Proapoptotic Bcl‑2 family members, BAX and Bcl‑2, were involved in oleuropein‑induced apoptosis. The phosphatidylinositol 3‑kinase/protein kinase B (PI3K/AKT) signaling pathway was also shown to be involved in this process. Oleuropein was demonstrated to suppress the expression of activated AKT. In addition, AKT overexpression promoted cell survival following treatment with oleuropein, while inhibition of AKT promoted cell death. Furthermore, the data demonstrated that oleuropein induces the production of reactive oxygen species (ROS) and that the function of oleuropein is, at least partially, ROS‑dependent. These results suggest that oleuropein may be a promising novel chemotherapeutic agent in hepatocellular carcinoma.

Oxidative stress and hepatic Nox proteins in chronic hepatitis C and hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common liver cancer and a leading cause of cancer-related mortality in the world. Hepatitis C virus (HCV) is a major etiologic agent of HCC. A majority of HCV infections lead to chronic infection that can progress to cirrhosis and, eventually, HCC and liver failure. A common pathogenic feature present in HCV infection, and other conditions leading to HCC, is oxidative stress. HCV directly increases superoxide and H2O2 formation in hepatocytes by elevating Nox protein expression and sensitizing mitochondria to reactive oxygen species generation while decreasing glutathione. Nitric oxide synthesis and hepatic iron are also elevated. Furthermore, activation of phagocytic NADPH oxidase (Nox) 2 of host immune cells is likely to exacerbate oxidative stress in HCV-infected patients. Key mechanisms of HCC include genome instability, epigenetic regulation, inflammation with chronic tissue injury and sustained cell proliferation, and modulation of cell growth and death. Oxidative stress, or Nox proteins, plays various roles in these mechanisms. Nox proteins also function in hepatic fibrosis, which commonly precedes HCC, and Nox4 elevation by HCV is mediated by transforming growth factor β. This review summarizes mechanisms of oncogenesis by HCV, highlighting the roles of oxidative stress and hepatic Nox enzymes in HCC.

Progression of liver oncogenesis in the double transgenic mice c-myc/TGF α is not enhanced by cyclooxygenase-2 expression

Cyclooxygenase-2 (COX-2) has been associated with cell growth regulation, tissue remodeling and carcinogenesis. Overexpression of COX-2 in hepatocytes constitutes an ideal condition to evaluate the role of prostaglandins (PGs) in liver pathogenesis. The effect of COX-2-dependent PGs in genetic hepatocarcinogenesis has been investigated in triple c-myc/transforming growth factor α (TGF-α) transgenic mice that express human COX-2 in hepatocytes on a B6CBAxCD1xB6DBA2 background. Analysis of the contribution of COX-2-dependent PGs to the development of hepatocarcinogenesis, evaluated in this model, suggested a minor role of COX-2-dependent prostaglandins to liver oncogenesis as indicated by liver histopathology, morphometric analysis and specific markers of tumor progression. This allows concluding that COX-2 is insufficient for modifying the hepatocarcinogenesis course mediated by c-myc/TGF-α.

Oxidative status interactome map: towards novel approaches in experiment planning, data analysis, diagnostics and therapy

Experimental evidence suggests an immense variety of processes associated with and aimed at producing reactive oxygen and/or nitrogen species. Clinical studies implicate an enormous range of pathologies associated with reactive oxygen/nitrogen species metabolism deregulation, particularly oxidative stress. Recent advances in biochemistry, proteomics and molecular biology/biophysics of cells suggest oxidative stress to be an endpoint of complex dysregulation events of conjugated pathways consolidated under the term, proposed here, "oxidative status". The oxidative status concept, in order to allow for novel diagnostic and therapeutic approaches, requires elaboration of a new logic system comprehending all the features, versatility and complexity of cellular pro- and antioxidative components of different nature. We have developed a curated and regularly updated interactive interactome map of human cellular-level oxidative status allowing for systematization of the related most up-to-date experimental data. A total of more than 600 papers were selected for the initial creation of the map. The map comprises more than 300 individual factors with respective interactions, all subdivided hierarchically for logical analysis purposes. The pilot application of the interactome map suggested several points for further development of oxidative status-based technologies.

Non-alcoholic fatty liver disease contributes to hepatocarcinogenesis in non-cirrhotic liver: a clinical and pathological study

BACKGROUND AND AIM

Hepatocellular carcinoma (HCC) is a major complication of cirrhosis and has been increasing in incidence in recent years. Fatty liver disease is an increasingly common cause of chronic liver disease, and there have been several case reports of HCC in patients with non-cirrhotic fatty liver disease. However, there is limited data from systematic studies with histological confirmation of the presence of both the HCC and the non-cirrhotic fatty liver disease.

METHODS

We studied the occurrence of fatty liver disease and the associated demographic, clinical, and pathological characteristics of a large cohort of patients with HCC in non-cirrhotic livers. Patients with intrahepatic cholangiocarcinoma (CC) occurring in non-cirrhotic livers and diagnosed during the same time period were used as the comparison group.

RESULTS

Significant steatosis in the nontumor liver had a statistically significant association with HCC, being present in 54% (85/157) of HCC compared with 27% (32/120) of CC (P < 0.0001). Steatohepatitis was present in 15% (24/157) of HCC and 1% (2/120) of CC (P = 0.0014). Furthermore, HCC was more prevalent in cases with higher grades of steatosis. In addition, the recently described intratumoral steatohepatitic morphology of HCC (SH-HCC) was also associated with significant steatosis in nontumor liver, with significant steatosis being present in 89% with SH-HCC compared with 50% without SH-HCC (P = 0.0162). Finally, SH-HCC was increasingly more prevalent in patients with higher grades of nontumor steatosis.

CONCLUSIONS

Taken together, these findings suggest a strong association between fatty liver disease and HCC in non-cirrhotic livers.

A vitamin-E-fortified diet reduces oxidative stress, sympathetic nerve activity, and hypertension in the phenol-renal injury model in rats

Renal injury caused by the injection of phenol in the lower pole of one kidney increases sympathetic nervous system (SNS) activity and blood pressure (BP), and these effects are mediated by increased reactive oxygen species (ROS) in brain nuclei involved in the noradrenergic control of BP. This suggests that therapy with antioxidants might be beneficial in this model. In this study, we tested the hypothesis that a vitamin (Vit)-E-enriched diet might decrease oxidative stress in the brain and result in reduced SNS activity and BP in animals with phenol-renal injury. To this end, we examined the effects of a Vit-E-fortified diet vs. a control diet on BP, norepinephrine (NE) secretion from the posterior hypothalamic nuclei (PH), and the abundance of several components of Nicotinamide Adenine Dinucleotide Phosphate (NADPH) oxidase in the brain of rats with phenol-induced renal injury. A Vit-E-fortified diet mitigated the formation of ROS in the brain, and this was associated with reduced SNS activity and BP in rats with phenol-induced renal injury. In conclusion, antioxidants appear to be beneficial in the management of hypertension caused by renal injury and increased SNS activity.

The NADPH oxidase inhibitor VAS2870 impairs cell growth and enhances TGF-β-induced apoptosis of liver tumor cells

Liver tumor cells show several molecular alterations which favor pro-survival signaling. Among those, we have proposed the NADPH oxidase NOX1 as a prosurvival signal for liver tumor cells. On the one side, we have described that FaO rat hepatoma cells show NOX1-dependent partial resistance to apoptosis induced by Transforming Growth Factor beta (TGF-β). On the other side, we have shown that FaO cells, as well as different human hepatocellular carcinoma (HCC) cell lines, are able to proliferate in the absence of serum through the activation of a NOX1-dependent signaling pathway. The aim of this work was to analyze the effects of NADPH oxidase pharmacological inhibition in liver tumor cells using the inhibitor VAS2870. This compound inhibits dose-dependently autocrine increase of cell number in FaO rat hepatoma cells, and almost completely blocked ROS production and thymidine incorporation when used at 25μM. Such inhibitory effect on autocrine growth is coincident with lower mRNA levels of EGFR (Epidermal Growth Factor Receptor) and its ligand TGF-α (Transforming Growth Factor-alpha), and decreased phosphorylation of the EGFR itself and other downstream targets, such as SRC or AKT. Moreover, NADPH oxidase pharmacological inhibition also effectively attenuates serum-dependent growth and phosphorylation of AKT and ERK. Importantly, these inhibitory effects on either autocrine or serum-dependent cell growth are observed in several human HCC cell lines. Finally, we have observed that VAS2870 is also effective in enhancing apoptosis induced by a physiological stimulus, such as TGF-β. In summary, NADPH oxidase pharmacological inhibition could be considered a promising tool in the treatment of liver cancer.

The role of XPD in cell apoptosis and viability and its relationship with p53 and cdk2 in hepatoma cells

We investigated the role of XPD in cell apoptosis of hepatoma and its relationship with p53 during the regulation of hepatoma bio-behavior. RT-PCR and Western blot were used to detect the expression levels of XPD, p53, c-myc, and cdk2. The cell apoptosis and cell cycle were analyzed with flow cytometry. Compared with the control cells, XPD-transfected cells displayed a lower viability and higher apoptosis rate. A decreased expression of p53 gene was detected in XPD-transfected cells. In contrast, both c-myc and cdk2 showed increased expressions of mRNAs and proteins in the transfected cells. Our results indicate that XPD may play an important role in cell apoptosis of hepatoma by inducing an over-expression of p53, but suppressing expressions of c-myc and cdk2.

Oxidative stress, inflammation, and cancer: how are they linked?

Extensive research during the past 2 decades has revealed the mechanism by which continued oxidative stress can lead to chronic inflammation, which in turn could mediate most chronic diseases including cancer, diabetes, and cardiovascular, neurological, and pulmonary diseases. Oxidative stress can activate a variety of transcription factors including NF-κB, AP-1, p53, HIF-1α, PPAR-γ, β-catenin/Wnt, and Nrf2. Activation of these transcription factors can lead to the expression of over 500 different genes, including those for growth factors, inflammatory cytokines, chemokines, cell cycle regulatory molecules, and anti-inflammatory molecules. How oxidative stress activates inflammatory pathways leading to transformation of a normal cell to tumor cell, tumor cell survival, proliferation, chemoresistance, radioresistance, invasion, angiogenesis, and stem cell survival is the focus of this review. Overall, observations to date suggest that oxidative stress, chronic inflammation, and cancer are closely linked.

NADPH oxidase NOX1 controls autocrine growth of liver tumor cells through up-regulation of the epidermal growth factor receptor pathway

FaO rat hepatoma cells proliferate in the absence of serum through a mechanism that requires activation of the epidermal growth factor receptor (EGFR) pathway. The aim of this work was to analyze the molecular mechanisms that control EGFR activation in these and other liver tumor cells. Reactive oxygen species production is observed a short time after serum withdrawal in FaO cells, coincident with up-regulation of the NADPH oxidase NOX1. NOX1-targeted knockdown, the use of antioxidants, or pharmacological inhibition of NADPH oxidase attenuates autocrine growth, coincident with lower mRNA levels of EGFR and its ligand transforming growth factor-alpha (TGF-alpha) and a decrease in phosphorylation of EGFR. EGFR-targeted knockdown induces similar effects on cell growth and downstream signals to those observed in NOX1-depleted cells. Early NOX1 activation induces both a feedback-positive loop via an Src-ERK pathway that up-regulates its own levels, and a parallel signaling pathway through p38 MAPK and AKT resulting in EGFR and TGF-alpha up-regulation. Human hepatocellular carcinoma cell lines, but not non-tumoral hepatocytes, show autocrine growth upon serum withdrawal, which is also coincident with NOX1 up-regulation that mediates EGFR and TGF-alpha expression. The use of antioxidants, or pharmacological inhibition of NADPH oxidase, effectively attenuates autocrine growth in hepatocellular carcinoma cell lines. In summary, results presented in this study indicate that NOX1 might control autocrine cell growth of liver tumor cells through regulation of the EGFR pathway.

Vitamin E regulates adipocytokine expression in a rat model of dietary-induced obesity

The aim of this study was to determine the effect of the antioxidant vitamin E (VE) on adiponectin and leptin expression in obese rats. Thirty weaning male Sprague-Dawley rats were divided into three groups as follows: (1) a control group, fed with normal chow; (2) a diet-induced obesity group (DIO), fed with a high-fat diet and (3) an intervention group, fed with a high-fat diet supplemented with VE (350 mg/kg). After 10 weeks of being fed according to these group assignments, rats were weighed and euthanized. Blood and adipose tissues were then immediately collected; mRNA and protein levels of leptin and adiponectin were measured by realtime reverse transcription-polymerase chain reaction and Western blotting. Biomarkers of oxidative stress, including serum levels of 8-epi-prostaglandin-F(2)alpha (8-epi-PGF(2)alpha) and glutathione peroxidase activity, were also examined. Adiponectin and leptin levels were lower in the DIO group than in the control group. VE intervention increased the expression of both leptin and adiponectin (P values < 0.05). Association analysis showed that serum leptin levels correlated positively with body fat mass (r = 0.601, P < 0.05). Both serum leptin and adiponectin levels were associated with the presence of serum 8-epi-PGF2 alpha (leptin, r = 0.513, P < 0.05; adiponectin, r = -0.422, P < 0.05). Administration of VE decreases leptin and adiponectin expression in obese rats. This finding is consistent with the view that antioxidants can play an important role in the treatment of obesity-related diseases.

Effects of vitamin E and sodium selenate on impaired contractile activity by bacterial lipopolysaccharide in the rat vas deferens

We investigated whether bacterial lipopolysaccharide (LPS) treatment causes any hyporeactivity in rat vas deferens tissue and also whether vitamin E or sodium selenate has any restorative effect on this possible hyporesponsiveness. LPS treatment attenuated contractions to electrical field stimulation (EFS), phenylephrine, or ATP at the prostatic and epididymal ends. Treatment with the inducible nitric oxide synthase (iNOS) inhibitor aminoguanidine or vitamin E could prevent the impairment in contractile responses of both ends to EFS and phenylephrine but sodium selenate could restore these impaired contractions at only the epididymal end. LPS treatment also caused a similar significantly impairment on purinergic or adrenergic component of nerve-evoked contractions in the presence of prazosin or suramin, respectively, and vitamin E or sodium selenate could restored this impairment at both ends. On the other hand, both antioxidant agents failed to restore the impaired ATP-induced contractions in LPS-treated rats at both ends. In conclusion, LPS-treatment caused a hyporeactivity in the rat vas deferens. A possible increased oxidative activity in the vas deferens may be a major reason for the impairment of contractile responses. The restorative effects of vitamin E and/or sodium selenate on this hypocontractility may depend on their antioxidant properties or their inhibitory action on the iNOS.

Use of conventional and -omics based methods for health claims of dietary antioxidants: a critical overview

This article describes the principles and limitations of methods used to investigate reactive oxygen species (ROS) protective properties of dietary constituents and is aimed at providing a better understanding of the requirements for science based health claims of antioxidant (AO) effects of foods. A number of currently used biochemical measurements aimed of determining the total antioxidant capacity and oxidised lipids and proteins are carried out under unphysiological conditions and are prone to artefact formation. Probably the most reliable approaches are measurements of isoprostanes as a parameter of lipid peroxidation and determination of oxidative DNA damage. Also the design of the experimental models has a strong impact on the reliability of AO studies: the common strategy is the identification of AO by in vitro screening with cell lines. This approach is based on the assumption that protection towards ROS is due to scavenging, but recent findings indicate that activation of transcription factors which regulate genes involved in antioxidant defence plays a key role in the mode of action of AO. These processes are not adequately represented in cell lines. Another shortcoming of in vitro experiments is that AO are metabolised in vivo and that most cell lines are lacking enzymes which catalyse these reactions. Compounds with large molecular configurations (chlorophylls, anthocyans and polyphenolics) are potent AO in vitro, but weak or no effects were observed in animal/human studies with realistic doses as they are poorly absorbed. The development of -omics approaches will improve the scientific basis for health claims. The evaluation of results from microarray and proteomics studies shows that it is not possible to establish a general signature of alterations of transcription and protein patterns by AO. However, it was shown that alterations of gene expression and protein levels caused by experimentally induced oxidative stress and ROS related diseases can be normalised by dietary AO.

Interaction of major genes predisposing to hepatocellular carcinoma with genes encoding signal transduction pathways influences tumor phenotype and prognosis

Studies on rodents and humans demonstrate an inherited predisposition to hepatocellular carcinoma (HCC). Analysis of the molecular alterations involved in the acquisition of a phenotype resistant or susceptible to hepatocarcinogenesis showed a deregulation of G1 and S phases in HCC of genetically susceptible F344 rats and a G1-S block in lesions of resistant Brown norway (BN) rats. Unrestrained extracellular signal-regulated kinase (ERK) activity linked to proteasomal degradation of dual-specificity phosphatase 1 (DUSP1), a specific ERK inhibitor, by the CKS1-SKP2 ubiquitin ligase complex occurs in more aggressive HCC of F344 rats and humans. This mechanism is less active in HCC of BN rats and human HCC with better prognosis. Upregulation of iNos cross-talk with IKK/NF-κB and RAS/ERK pathways occurs in rodent liver lesions at higher levels in the most aggressive models represented by HCC of F344 rats and c-Myc-TGF-α transgenic mice. iNOS, IKK/NF-κB, and RAS/ERK upregulation is highest in human HCC with a poorer prognosis and positively correlates with tumor proliferation, genomic instability and microvascularization, and negatively with apoptosis. Thus, cell cycle regulation and the activity of signal transduction pathways seem to be modulated by HCC modifier genes, and differences in their efficiency influence the susceptibility to hepatocarcinogenesis and probably the prognosis of human HCC.