Effect of two selenium sources on hepatocarcinogenesis and several angiogenic cytokines in diethylnitrosamine-induced hepatocarcinoma rats

Effect of selenium on the dysfunction of rat salivary glands induced by 131I and expression of insulin-like growth factors and aquaporins

OBJECTIVES

To investigate the effects of selenium on functional and histopathological changes and mRNA expression levels of insulin-like growth factors 1 and 2 (IGF-1 and -2) and aquaporins 4 and 5 (AQP-4 and -5) in 131I-induced damaged rat parotid glands.

METHODS

Rats were divided into three groups: iodotherapy-with-selenium, iodotherapy-only, and control. Rats in the iodotherapy-with-selenium group were intragastrically administered 131I on the first day and selenomethionine through drinking water. Rats in the iodotherapy-only group were only administered 131I. Changes in parotid gland function were evaluated using the functional parameters of salivary gland dynamics imaging pre-experiment and on days 7, 30, and 90 post-treatment. Immunofluorescence and quantitative real-time PCR analyses detected IGF-1, IGF-2, AQP-4, and AQP-5 expression levels in tissues.

RESULTS

The gland-to background ratio at a maximum count (G/BGmax), Tmax/Tmin, and Smax values were significantly impacted over time in the iodotherapy-with-selenium group; on day 30, the G/BGmax value was significantly higher than that in the iodotherapy-only group. Histopathological analysis revealed that on days 30 and 90, the iodotherapy-with-selenium group displayed greater parotid gland repair than the iodotherapy-only group. In the iodotherapy-with-selenium group, fluorescence intensity and mRNA levels of AQP-5 increased with the selenium supplementation period, reaching significantly higher levels on days 30 and 90 than in the iodotherapy-only group. Whereas the fluorescence intensity and mRNA levels of IGF-1 in the iodotherapy-with-selenium group were significantly higher on day 7 than on day 30 in the iodotherapy-only group.

CONCLUSION

Selenium may repair 131I-induced tissue and functional damage in rat salivary glands by upregulating AQP-5 and IGF-1 expression.

Glutathione and Selenium Supplementation Attenuates Liver Injury in Diethylnitrosamine-Induced Hepatocarcinogenic Mice by Enhancing Glutathione-Related Antioxidant Capacities

Excess oxidative stress and inadequate antioxidant capacities are critical features in the development of hepatocellular carcinoma. This study aimed to determine whether supplementation with glutathione (GSH) and/or selenium (Se), as antioxidants, attenuates diethylnitrosamine (DEN)-induced hepatocarcinogenesis in mice. C57BL/6J male mice were randomly assigned to control, DEN, DEN + GSH, DEN + Se, and DEN + GSH + Se groups for 20 weeks. Daily supplementation with GSH and/or Se commenced in the first experimental week and continued throughout the study. DEN was administered in weeks 2-9 and 16-19 of the experimental period. DEN administration induced significant pathological alterations of hepatic foci, evidenced by elevated levels of liver function, accompanied by high malondialdehyde (MDA) levels; low GSH levels; and glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione S-transferase (GST) activities. Supplementation with GSH and Se significantly ameliorated liver pathological changes, reducing liver function and MDA levels while increasing GSH levels and GPx, GR, and GST activities. Notably, combined supplementation with GSH and Se more effectively increased the GSH/glutathione disulfide ratio and GPx activity than individual supplementation. Supplementation with GSH and Se attenuated liver injury in DEN-induced hepatocarcinogenic mice by enhancing GSH and its related antioxidant capacities, thereby mitigating oxidative damage.

Current Trends on the Involvement of Zinc, Copper, and Selenium in the Process of Hepatocarcinogenesis

Numerous nutritional factors increase the risk of hepatocellular carcinoma (HCC) development. The dysregulation of zinc, copper, and selenium homeostasis is associated with the occurrence of HCC. The impairment of the homeostasis of these essential trace elements results in oxidative stress, DNA damage, cell cycle progression, and angiogenesis, finally leading to hepatocarcinogenesis. These essential trace elements can affect the microenvironment in HCC. The carrier proteins for zinc and copper and selenium-containing enzymes play important roles in the prevention or progression of HCC. These trace elements enhance or alleviate the chemosensitivity of anticancer agents in patients with HCC. The zinc, copper, or selenium may affect the homeostasis of other trace elements with each other. Novel types of cell death including ferropotosis and cupropotosis are also associated with hepatocarcinogenesis. Therapeutic strategies for HCC that target these carrier proteins for zinc and copper or selenium-containing enzymes have been developed in in vitro and in vivo studies. The use of zinc-, copper- or selenium-nanoparticles has been considered as novel therapeutic agents for HCC. These results indicate that zinc, copper, and selenium may become promising therapeutic targets in patients with HCC. The clinical application of these agents is an urgent unmet requirement. This review article highlights the correlation between the dysregulation of the homeostasis of these essential trace elements and the development of HCC and summarizes the current trends on the roles of these essential trace elements in the pathogenesis of hepatocarcinogenesis.

Long-term effect of sodium selenite on the integrity and permeability of on-chip microvasculature

Development of the robust and functionally stable three-dimensional (3D) microvasculature remains challenging. One often-overlooked factor is the presence of potential anti-angiogenic agents in culture media. Sodium selenite, an antioxidant commonly used in serum-free media, demonstrates strong anti-angiogenic properties and has been proposed as an anticancer drug. However, its long-term effects on in vitro microvascular systems at the concentrations used in culture media have not been studied. In this study, we used a five-channel microfluidic device to investigate the concentration and temporal effects of sodium selenite on the morphology and functionality of on-chip preformed microvasculature. We found that high concentrations (∼3.0 μM) had adverse effects on microvasculature perfusion, permeability, and overall integrity within the first few days. Moreover, even at low concentrations (∼3.0 nM), a long-term culture effect was observed, resulting in an increase in vascular permeability without any noticeable changes in morphology. A further analysis suggested that vessel leakage may be due to vascular endothelial growth factor dysregulation, disruption of intracellular junctions, or both. This study provides important insight into the adverse effects caused by the routinely present sodium selenite on 3D microvasculature in long-term studies for its application in disease modeling and drug screening.

The modulatory effect of bee honey against diethyl nitrosamine and carbon tetrachloride instigated hepatocellular carcinoma in Wistar rats

Hepatocellular carcinoma (HCC) is a serious threat to human health that has attracted substantial interest. The purpose of this study was to investigate the modulatory effect of bee honey against induced HCC by diethylnitrosamine/carbon tetrachloride (DEN/CCl4) in rats. HCC was induced by a single intraperitoneal dose of DEN (200 mg/kg B.W). Two weeks later, CCl4 (1 ml/kg) was intraperitoneally injected (three times a week). Bee honey was administered orally at 2 g/rat before and after the induction of HCC. The results showed that bee honey administration significantly increased body weight, decreased liver weight, and relative liver weight compared to those in the HCC-induced group. Moreover, a significant decrease in serum alpha-fetoprotein (AFP) as well as AST, ALT, GGT, ALP activities were observed in bee honey administration rats compared with those in HCC-induced group. Also, the hepatic MDA was significantly decreased; in addition, SOD, CAT, and GPx activities were significantly increased in groups treated with bee honey compared with those in the HCC group. The hepatic histopathology alterations caused by DEN/CCl4 injection were ameliorated by bee honey treatment. Likewise, the mRNA expression levels of tumor necrosis factor-alpha (TNF-α), transforming growth factor (TGF-β1), intracellular adhesion molecule-1 (ICAM-1), vascular cellular adhesion molecule-1 (VCAM-1), glypican (GP-3), thioredoxin (TRX), and glutaredoxin (GRX) were downregulated, and caspase-3 was upregulated by bee honey treatment compared with untreated HCC-induced group. In conclusion, bee honey has remarkable beneficial effects against HCC induced in rats through its antioxidant, anti-inflammatory, antifibrotic, and antimetastatic effects.

PRACTICAL APPLICATIONS

The current study confirmed that honey has the potential to act as an antimetastatic factor. Bee honey supplementation either before or after combined injection of DEN/CCl4 exhibited inhibitory and ameliorative effects against DEN/CCl4-induced HCC through its antioxidant, antiproliferative, anti-metastatic, antifibrotic, and apoptosis properties. To our knowledge, this is the first study to describe the molecular mechanisms underlying honey's effects against DEN/CCl4-induced HCC in rats.

A novel therapeutic strategy for hepatocellular carcinoma: Immunomodulatory mechanisms of selenium and/or selenoproteins on a shift towards anti-cancer

Selenium (Se) is an essential trace chemical element that is widely distributed worldwide. Se exerts its immunomodulatory and nutritional activities in the human body in the form of selenoproteins. Se has increasingly appeared as a potential trace element associated with many human diseases, including hepatocellular carcinoma (HCC). Recently, increasing evidence has suggested that Se and selenoproteins exert their immunomodulatory effects on HCC by regulating the molecules of oxidative stress, inflammation, immune response, cell proliferation and growth, angiogenesis, signaling pathways, apoptosis, and other processes in vitro cell studies and in vivo animal studies. Se concentrations are generally low in tissues of patients with HCC, such as blood, serum, scalp hair, and toenail. However, Se concentrations were higher in HCC patient tissues after Se supplementation than before supplementation. This review summarizes the significant relationship between Se and HCC, and details the role of Se as a novel immunomodulatory or immunotherapeutic approach against HCC.

Food Sources of Selenium and Its Relationship with Chronic Diseases

Selenium (Se) is an essential micronutrient for mammals, and its deficiency seriously threatens human health. A series of biofortification strategies have been developed to produce Se-enriched foods for combating Se deficiency. Although there have been some inconsistent results, extensive evidence has suggested that Se supplementation is beneficial for preventing and treating several chronic diseases. Understanding the association between Se and chronic diseases is essential for guiding clinical practice, developing effective public health policies, and ultimately counteracting health issues associated with Se deficiency. The current review will discuss the food sources of Se, biofortification strategies, metabolism and biological activities, clinical disorders and dietary reference intakes, as well as the relationship between Se and health outcomes, especially cardiovascular disease, diabetes, chronic inflammation, cancer, and fertility. Additionally, some concepts were proposed, there is a non-linear U-shaped dose-responsive relationship between Se status and health effects: subjects with a low baseline Se status can benefit from Se supplementation, while Se supplementation in populations with an adequate or high status may potentially increase the risk of some diseases. In addition, at supra-nutritional levels, methylated Se compounds exerted more promising cancer chemo-preventive efficacy in preclinical trials.

Inhibitory and ameliorative effect of heliomycin derived from actinomycete on induced hepatocellular carcinoma in rats

The hepatoprotective activity of heliomycin obtained from the culture broth of actinomycete AB5 against diethylnitrosamine (DEN)-induced hepatic cancer in Wistar rats was estimated. Heliomycin exhibited a significant decrease in the levels of alanine transaminase (ALT), aspartate transaminase (AST), and alkaline phosphatase (ALP) compared to the positive control. For instance, the heliomycin group after 20 weeks showed a significant decline in ALT, AST, and ALP values (70.75 ± 5.12, 140.25 ± 11.75, and 163.25 ± 18.66, respectively) compared to the positive control group (170.00 ± 9.55, 252.75 ± 12.33, and 278.00 ± 21.32, respectively). Additionally, the isolated compound showed a highly significant decrease in serum alpha-fetoprotein (AFP) levels. After 8, 16, and 20 weeks, the mean values of AFP in the heliomycin group revealed a highly significant decrease (33.62 ± 2.46, 30.00 ± 4.05, and 28.50 ± 2.64, respectively) compared to the positive control group (49.45 ± 3.03, 81.90 ± 6.70, and 90.75 ± 5.12, respectively). The histopathological investigation of liver sections supported the results of biochemical analysis. It was demonstrated that heliomycin showed histological improvement of hepatocytes and marked increase of nuclear pyknotic with clear cytoplasm, which is a sign of improving the apoptotic pathway of malignant cells. It also displayed marked fibrosis at most of the malignant cells and the development of some regenerative nodules. Heliomycin showed moderate immunoreactivity with alpha-fetoprotein (AFP), and proliferation cell nuclear antigen (PCNA) compared to the positive control group. To the best of our knowledge, this is the first study to report the anticancer activity of heliomycin against hepatocellular carcinoma in vivo.

Selenium concentration, dietary intake and risk of hepatocellular carcinoma - A systematic review with meta-analysis

Aim: this study was performed to investigate the association between selenium concentrations, dietary intake, and the risk of hepatocellular carcinoma (HCC). Methods: we identified eligible studies in PubMed and EMBASE databases, in addition to the reference lists of original studies and review articles on this topic, up to 1 Feb 2019. A summary of standardized mean differences (SMD) with 95% confidence intervals (CI) was calculated using a random-effects model. Heterogeneity between studies was assessed using Cochran Q and I2 statistics. Results: finally, a meta-analysis showed that dietary intake of selenium and tissue selenium concentration were not associated with HCC risk (dietary SMD = -0.11, 95% CI: -0.26 to 0.03; tissue SMD = -0.12, 95% CI: -0.56 to 0.33). However, samples from toenail, whole blood, and serum all showed an inverse association with HCC risk (toenail SMD = -0.53, 95% CI: -0.72 to -0.35; whole blood SMD = -2.21, 95% CI: -2.67 to -1.76; tissue SMD = -1.26, 95% CI: -1.71 to -0.81). Dose-response data from few studies showed that an extra increase in serum selenium was dramatically related with a lower risk of HCC (adjusted p-trend < 0.05). This study showed that selenium concentration in toenail, whole blood and serum was inversely associated with HCC risk. Conclusion: increased concentration in serum selenium was related to a lower risk of HCC. However, these results based on dietary intake and tissue samples, which included few studies, did not reach statistical significance.

Protective effects of selenium and nano-selenium on bisphenol-induced reproductive toxicity in male rats

Bisphenol A (BPA) is a widespread compound associated with the manufacture of many consumer products. The BPA-induced reproductive toxicity was reported to be mainly attributed to oxidative stress. However, the role of antioxidants usage to decrease the injurious effects of BPA, on male reproductive functions, remains to unveil. The present research is established to evaluate the role of selenium (Se) and its nano form (NSe) as protective agents to alleviate BPA-induced testicular toxicity. Ninety mature albino male rats were assigned into six equal groups: negative control; orally BPA 150 mg/kg; Se 3 mg/kg; NSe 2 mg/kg; both BPA 150 mg/kg and Se 3 mg/kg; and BPA 150 mg/kg + NSe 2 mg/kg. The experiment lasted for 70 consecutive days, and then serum was collected for estimation of prostatic acid phosphatase. Testicular tissues were subjected to measurement of antioxidant status, lipid peroxidation, DNA damage, and expression of some apoptotic genes. Our results reported that BPA-induced marked testicular damage evidenced by significant elevations in serum prostatic acid phosphatase activity, malondialdehyde levels, a decrease in testicular catalase activity and reduced glutathione level. Moreover, marked DNA internucleosomal fragmentation pattern as well as upregulation of cyclooxygenase-2 and estrogen receptor-2 NSe genes were detected. Coadministration of Se and NSe attenuated the reproductive toxicity induced by BPA via improvement of the antioxidant activity, genetic changes, and restoration of testicular tissue nearly as control one. These results indicated that both Se and NSe forms could be used as reproductive protective agents against the detrimental effect induced by BPA. However, the NSe surpassed the selenium in modulating the DNA laddering, and the studied gene expression levels, and offered a potent reproductive protection.

Evaluation of selenium nanoparticles and doxorubicin effect against hepatocellular carcinoma rat model cytogenetic toxicity and DNA damage

The present study aimed to demonstrate the potent role of nanoselenium and Doxorubicin in retrogression of genotoxicity induced in hepatocellular carcinoma rat model by studying chromosomal aberration, micronuclei formation, DNA fragmentation as well as comet assay. Male rats hepatocellular carcinoma model were treated with Se-Nanoparticles, Doxurobicin (DOX) and the combination of both. The results revealed the protective effect of nanoselenium, Doxorubicin and their combination on bone marrow cytogenetic toxicity by decreasing chromosomal aberrations and micronuclei formation as well as their effects on rat's liver by decreasing DNA damage. Nevertheless, the treatment with nanoselenium either alone or in combination with Doxorubicin was more effective than treatment with doxorubicin alone.

Meta-analysis of the correlation between selenium and incidence of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common cancer type. There is a correlation between selenium (Se) deficiency and the incidence of HCC. To clarify the effects of Se level on the risk of HCC patients, a meta-analysis was performed. A total of 9 articles published between 1994 and 2016 worldwide were selected through searching PubMed, EMBASE, web of science, Cochrane Library, Springer Link, Chinese National Knowledge Infrastructure (CNKI), and Chinese Biology Medicine (CBM), and the information were analyzed using a meta-analysis method. Heterogeneity was assessed by using the I² index. Publication bias was evaluated by Begg's Test analysis. Pooled analysis indicated that patients with HCC had lower Se levels than the healthy controls [standardized mean difference (SMD)= −1.08, 95% confidence intercal (CI) = (−0.136, −0.08), P < 0.001]. Further subgroup analysis showed this effect to be independent of the study design, race or sample collection. In conclusion, this meta-analysis suggested an inverse correlation between Se level and the risk of HCC in humans patients.

Administration of Selenium Decreases Lipid Peroxidation and Increases Vascular Endothelial Growth Factor in Streptozotocin Induced Diabetes Mellitus

Objective

The imbalance in oxidant/antioxidant status plays a pivotal role in diabetes mellitus (DM). Selenium is a integral component of the antioxidant enzyme glutathione peroxidase. Se treatment induces angiogenesis and improves endothelial function through increased expression of vascular endothelial growth factor (VEGF). The aim of this study is to investigate the effect of selenium on oxidative stress, VEGF, and endothelin 1 (ET1) in a DM rat model.

Materials and Methods

We performed an experimental animal study with 64 adult male Wistar-Albino rats. Rats were divided into the following groups (n=8): control (C)7, C21, C+sodium selenite (Se)7, and C+Se21 (control rats), and DM7, DM21, DM+Se7, and DM+Se21 (diabetic rats). Diabetes was induced by 2-deoxy-2-(3-methyl-3-nitrosoureido)- D-glucopyranose [streptozotocin (STZ)]. Three weeks after STZ, DM+Se7 rats received intraperitoneal (i.p.) injections of 0.4 mg/kg Se for 7 days. The DM+Se21 rats received these injections for 21 days. The same dose/duration of Se was administered to the C+Se7 and C+Se21 groups. The remaining rats (C7, C21, DM7, DM21) received physi- ologic saline injections for 7 or 21 days. Ferric reducing antioxidant power (FRAP), malon- dialdehyde (MDA), advanced oxidation protein products (AOPP), and endothelial function markers (VEGF and ET1) in plasma samples were measured.

Results

Diabetic rats (DM7 and DM21) had significantly increased plasma FRAP (P=0.002, P=0.001), AOPP (P=0.024, P=0.01), MDA (P=0.004, P=0.001), and ET1 (P=0.028, P=0.003) levels compared with C7 and C21 control rats. VEGF (P=0.02, P=0.01) significantly decreased in DM7 and DM21 diabetic rats compared with their controls (C7, C21). Se administration reversed the increased MDA and decreased VEGF levels, and lowered plasma glucose levels in the DM+Se7 and DM+Se21 diabetic groups compared with diabetic rats (DM7, DM21). We observed positive correlations between FRAP-AOPP (r=0.460), FRAP-ET1 (r=0.510), AOPP-MDA (r=0.270), and AOPP-ET1 (r=0.407), and a negative correlation between MDA-VEGF (r=-0.314).

Conclusion

We observed accentuated oxidative stress and impaired endothelial function in diabetes. Se treatment reduced lipid peroxidation and hyperglycemia. Se probably improved endothelial dysfunction in diabetic rats because of the increased VEGF levels.

Therapeutic role of a synthesized calcium phosphate nanocomposite material on hepatocarcinogenesis in rats

Nanotechnology research is booming worldwide, and the general belief is that medical and biological applications will form the greatest sector of expansion over the next decade. With this in mind, this study was designed to evaluate the therapeutic effects of a synthesized tricalcium phosphate nanocomposite material (nano-TCP) on hepatocarcinoma in a rat model, as initiated with diethylnitrosamine (DEN) and promoted with phenobarbital (PB). Hepatocarcinoma was induced with intraperitoneal injections of DEN (50 mg·(kg body mass)(-1)) 3 times a week for 2 weeks. Three weeks after the last dose of DEN, the rats received PB (0.05 %, w/v) in their drinking water for a further 6 weeks. Nano-TCP (100 mg·(kg body mass)(-1)) was administered intraperitoneally 3 times per week to rats with HCC. At the end of the experimental period, liver samples were collected from all animals for biochemical and histopathological analysis. The degree of DNA fragmentation was analyzed, in addition to immune status, by measuring the levels of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), and interleukin-2 (IL-2). The activities of the most important free-radical scavengers of the antioxidant defense system as well as malondialdehyde (MDA) content and liver enzymes were measured. The levels of hepatic heat shock protein-70 (HSP-70), caspase-3, and metalloproteinase-9 were also measured as markers for inflammation and apoptosis. Histopathological examination of liver tissue was performed. The results revealed the potent efficacy of nano-TCP in repairing the fragmented DNA and ameliorating most of the investigated parameters by significant elevation in the levels of hepatic alanine aminotransferase (ALT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) activities. On the other hand, there was a significant decrease in hepatic gamma-glutamyl transpeptidase (γ-GT), MDA, IL-2, IFN-γ, TNF-α, matrix metalloproteinase-9 (MMP-9), HSP-70, and caspase-3 levels upon treatment. The findings form histopathological examination of the liver tissues agreed with the biochemical results and confirmed the difference between the control and treatment groups. In conclusion, nano-TCP succeeded in treating hepatocarcinoma efficiently, and presents a new hope for patients to get safe, fast, and effective treatment.

Protective Effects of Selenium, Vitamin E, and Purple Carrot Anthocyanins on D-Galactose-Induced Oxidative Damage in Blood, Liver, Heart and Kidney Rats

The present study was performed to investigate the protective effects of selenium (Se), vitamin E (Vit E) and anthocyanins from purple carrots and their combination against the oxidative stress induced by D-galactose in rats. A total of 80 male rats were equally divided into 11 groups, one of which acted as control (I) just receiving intraperitoneal injections of physiological saline. The remaining ten groups (II-XI) were intraperitoneally injected with D-galactose at a dose of 400 mg kg(-1) body weight (BW) per day for 42 consecutive days. Rats in groups III-XI were treated with antioxidants via gavage per day as follows: group III: Se-methylselenocysteine (SeMSC), IV: Se as sodium selenite (Na2SeO3), V: Se-enriched yeast (SeY), VI: Vit E as α-tocopherol acetate, VII: anthocyanin from purple carrots (APC), VIII: APC + Vit E, IX: SeMSC + APC+ Vit E, X: Na2SeO3 + APC + Vit E, XI: SeY + Ant + Vit E. The results showed that the rats treated with antioxidants (III-XI) showed significant decreases in the levels of malondialdehyde (MDA) and carbonyl protein (PCO) compared with the D-galactose-treated group (II) in the heart, liver, kidneys, and blood. Moreover, there were significant increases in the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), glutathione (GSH) concentration, and total antioxidant capacity (T-AOC) in the heart, liver, kidneys, and blood of antioxidant-treated animals (III-XI) than those in control group (I). In addition, the combined treatments of two or three antioxidants showed greater antioxidant activities than those of individual treatments, suggesting the synergistic antioxidant effects of Se, Vit E, and APC. In conclusion, all the antioxidants exhibited protective effects against D-galactose-induced oxidative damage in rats, and these antioxidants showed a synergistic effect.

Effect of Different Selenium Supplementation Levels on Oxidative Stress, Cytokines, and Immunotoxicity in Chicken Thymus

This study assessed the effects of different selenium (Se) supplementation levels on oxidative stress, cytokines, and immunotoxicity in chicken thymus. A total of 180 laying hens (1 day old; Mianyang, China) were randomly divided into 4 groups (n = 45). The chickens were maintained either on a basic diet (control group) containing 0.2 mg/kg Se, a low-supplemented diet containing 5 mg/kg Se, a medium-supplemented diet containing 10 mg/kg Se, or a high-supplemented diet containing 15 mg/kg Se for 15, 30, and 45 days, respectively. Over the entire experimental period, serum and thymus samples were collected and used for the detection of the experimental index. The results indicated that the antioxidative enzyme activities and messenger RNA (mRNA) levels of antioxidative enzymes, IFN-γ and IL-2 in the thymus, and the content of IFN-γ and IL-2 in the serum of excessive-Se-treated chickens at all time points (except for the 5 mg/kg Se supplement group at 15 days) were significantly decreased (P < 0.05) compared to the corresponding control groups. Interestingly, a significantly increase (P < 0.05) in the content of IFN-γ was observed in the serum and thymus in the 5 mg/kg Se supplement group at 15 and 30 days compared to the corresponding control groups. In histopathological examination, the thymus tissue from excessive-Se-treated chickens revealed different degrees of cortex drop, incrassation of the medulla, and degeneration of the reticular cells. These results suggested that the excessive Se could result in a decrease in immunity, an increase in oxidative damage, and a series of clinical pathology changes, such as cortex drop, incrassation of the medulla, and degeneration of the reticular cells.

Prediagnostic selenium status and hepatobiliary cancer risk in the European Prospective Investigation into Cancer and Nutrition cohort

BACKGROUND

Selenium status is suboptimal in many Europeans and may be a risk factor for the development of various cancers, including those of the liver and biliary tract.

OBJECTIVE

We wished to examine whether selenium status in advance of cancer onset is associated with hepatobiliary cancers in the EPIC (European Prospective Investigation into Cancer and Nutrition) study.

DESIGN

We assessed prediagnostic selenium status by measuring serum concentrations of selenium and selenoprotein P (SePP; the major circulating selenium transfer protein) and examined the association with hepatocellular carcinoma (HCC; n = 121), gallbladder and biliary tract cancers (GBTCs; n = 100), and intrahepatic bile duct cancer (IHBC; n = 40) risk in a nested case-control design within the EPIC study. Selenium was measured by total reflection X-ray fluorescence, and SePP was determined by a colorimetric sandwich ELISA. Multivariable ORs and 95% CIs were calculated by using conditional logistic regression.

RESULTS

HCC and GBTC cases, but not IHBC cases, showed significantly lower circulating selenium and SePP concentrations than their matched controls. Higher circulating selenium was associated with a significantly lower HCC risk (OR per 20-μg/L increase: 0.41; 95% CI: 0.23, 0.72) but not with the risk of GBTC or IHBC. Similarly, higher SePP concentrations were associated with lowered HCC risk only in both the categorical and continuous analyses (HCC: P-trend ≤ 0.0001; OR per 1.5-mg/L increase: 0.37; 95% CI: 0.21, 0.63).

CONCLUSION

These findings from a large prospective cohort provide evidence that suboptimal selenium status in Europeans may be associated with an appreciably increased risk of HCC development.

Significance of Rumex vesicarius as anticancer remedy against hepatocellular carcinoma: a proposal-based on experimental animal studies

Rumex vesicarius is an edible herb distributed in Egypt and Saudi Arabia. The whole plant has significant value in folk medicine and it has been used to alleviate several diseases. Hepatocellular carcinoma (HCC), the major primary malignant tumor of the liver, is one of the most life-threatening human cancers. The goal of the current study was to explore the potent role of Rumex vesicarius extract against HCC induced in rats. Thirty adult male albino rats were divided into 3 groups: (I): Healthy animals received orally 0.9% normal saline and served as negative control group, (II): HCC group in which rats were orally administered N-nitrosodiethylamine NDEA, (III): HCC group treated orally with R. vesicarius extract in a dose of 400 mg/kg b.wt daily for two months. ALT and AST, ALP and γ-GT activities were estimated. CEA, AFP, AFU, GPC-3, Gp-73 and VEGF levels were quantified. Histopathological examination of liver tissue sections was also carried out. The results of the current study showed that the treatment of the HCC group with R. vesicarius extract reversed the significant increase in liver enzymes activity, CEA, AFP, AFU, glypican 3, golgi 73 and VEGF levels in serum as compared to HCC-untreated counterparts. In addition, the favorable impact of R. vesicarius treatment was evidenced by the marked improvement in the histopathological features of the liver of the treated group. In conclusion, the present experimental setting provided evidence for the significance of R. vesicarius as anticancer candidate with a promising anticancer potential against HCC. The powerful hepatoprotective properties, the potent antiangiogenic activity and the effective antiproliferative capacity are responsible for the anticancer effect of this plant.

Selenium and vitamin E for prostate cancer--justifications for the SELECT study

There are several studies that relate oxidative damage as possible mechanism for many cancers. Many studies have also shown that anti-oxidants like selenium and vitamin E decrease the risk for prostate cancer. The main objective of the Selenium and Vitamin E Cancer Prevention Trial (SELECT) study was to look for the benefits of selenium and vitamin E supplementation on prostate cancer. The study had a large sample size, stringent experimental conditions, very long duration, standardized laboratories for biochemical analyses and other factors that contribute to high external validity. The SELECT study failed to show any significant risk reduction for prostate cancers ascribable to selenium and vitamin E supplementations. Because of these conflicting results, many researchers argue about the methods used, supplementations administered (selenium and vitamin E) and indicators used for assessing levels of supplementations. We reviewed many epidemiological studies, clinical trials, and pre-clinical studies. With corroborative evidences we justify that SELECT study has a sound methodology and rationale. In lieu of the contrary results of the select study, researchers should focus on the probable mechanisms for these contrary findings and continue their search for newer and effective agents for prevention of prostate cancer.

Immunomodulatory effect of Stichopus japonicus acid mucopolysaccharide on experimental hepatocellular carcinoma in rats

Stichopus japonicus acid mucopolysaccharide (SJAMP) is an important biologically active compound that can be extracted from the body wall of the sea cucumber. The present study investigated the anti-tumor and immunomodulatory effects of SJAMP in an experimental hepatocellular carcinoma (HCC) model in rats. Three doses of SJAMP (17.5 mg/kg, 35 mg/kg, and 70 mg/kg administered 5 days/week via oral gavage) were given to rats with diethylnitrosamine (DEN)-induced HCC. SJAMP treatment significantly inhibited DEN-induced HCC by reducing both the number and mean volume of nodules, decreasing serum a-fetoprotein (AFP) levels and proliferating cell nuclear antigen (PCNA) expression in liver, and increasing p21 expression. Furthermore, SJAMP decreased the serum levels of ALT, AST, GGT and TNF-α and increased serum IL-2. SJAMP administration also improved indices of spleen and thymus function and improved both macrophage phagocytosis and NK cell-mediated tumoricidal activity. Moreover, CD3+ and CD4+ T lymphocyte levels recovered significantly and the CD4+/CD8+ T cell ratio normalized in a dose-dependent manner. In conclusion, SJAMP effectively inhibited the growth of HCC through the stimulation of immune organs and tissue proliferation, leading to the enhancement of cellular immunity pathways in rats.

Is selenium a potential treatment for cancer metastasis?

Selenium (Se) is an essential micronutrient that functions as a redox gatekeeper through its incorporation into proteins to alleviate oxidative stress in cells. Although the epidemiological data are somewhat controversial, the results of many studies suggest that inorganic and organic forms of Se negatively affect cancer progression, and that several selenoproteins, such as GPXs, also play important roles in tumor development. Recently, a few scientists have examined the relationship between Se and metastasis, a late event in cancer progression, and have evaluated the potential of Se as an anti-angiogenesis or anti-metastasis agent. In this review, we present the current knowledge about Se compounds and selenoproteins, and their effects on the development of metastasis, with an emphasis on cell migration, invasion, and angiogenesis. In the cancers of breast, prostate, colorectal, fibrosarcoma, melanoma, liver, lung, oral squamous cell carcinoma, and brain glioma, there is either clinical evidence linking selenoproteins, such as thioredoxin reductase-1 to lymph node metastasis; in vitro studies indicating that Se compounds and selenoproteins inhibited cell motility, migration, and invasion, and reduced angiogenic factors in some of these cancer cells; or animal studies showing that Se supplementation resulted in reduced microvessel density and metastasis. Together, these data support the notion that Se may be an anti-metastastatic element in addition to being a cancer preventative agent.