A comparative study of selenium concentration and glutathione peroxidase activity in normal and breast cancer patients

Antioxidative, Anti-Inflammatory, Anti-Obesogenic, and Antidiabetic Properties of Tea Polyphenols-The Positive Impact of Regular Tea Consumption as an Element of Prophylaxis and Pharmacotherapy Support in Endometrial Cancer

Endometrial cancer (EC) is second only to cervical carcinoma among the most commonly diagnosed malignant tumours of the female reproductive system. The available literature provides evidence for the involvement of 32 genes in the hereditary incidence of EC. The physiological markers of EC and coexisting diet-dependent maladies include antioxidative system disorders but also progressing inflammation; hence, the main forms of prophylaxis and pharmacotherapy ought to include a diet rich in substances aiding the organism’s response to this type of disorder, with a particular focus on ones suitable for lifelong consumption. Tea polyphenols satisfy those requirements due to their proven antioxidative, anti-inflammatory, anti-obesogenic, and antidiabetic properties. Practitioners ought to consider promoting tea consumption among individuals genetically predisposed for EC, particularly given its low cost, accessibility, confirmed health benefits, and above all, suitability for long-term consumption regardless of the patient’s age. The aim of this paper is to analyse the potential usability of tea as an element of prophylaxis and pharmacotherapy support in EC patients. The analysis is based on information available from worldwide literature published in the last 15 years.

Relationship Between Selenium in Human Tissues and Breast Cancer: a Meta-analysis Based on Case-Control Studies

Breast cancer is a common malignant tumor in women, and the anti-cancer effect of selenium (Se) is recognized. This meta-analysis was designed to determine the relationship between selenium levels in human tissue and breast cancer risk. Literatures published before August 2020 were systematically screened through PubMed, Web of Science, Scopus, and Elsevier. The related publication quality was evaluated by the Newcastle-Ottawa scale. We used random effect models for calculation and conducted sensitivity analysis and evaluation of publication bias. We identified 18 case-control studies, including 3374 women diagnosed with breast cancer and 3582 healthy controls. The results showed that the difference between the case group and the control group was - 0.53 μg/l [95%CI - 0.72 to - 0.34] (P < 0.001). Subgroup analysis showed a serum difference of - 1.14 μg/l [95%CI - 1.70 to - 0.58] (P < 0.001). The value of plasma was - 0.21 μg/l [95% CI - 0.37 to - 0.04] (P = 0.014). The value of toenail was - 0.21 μg/l [95% CI - 0.38 to - 0.03] (P = 0.021). In contrast, selenium levels in hair were not significantly associated with breast cancer risk. In the case-control studies, it was observed that selenium level in human tissues was negatively correlated with the risk of breast cancer, which may improve the understanding of the effects of selenium on human health.

Molecular mechanisms, immune cell infiltration, and potential drugs for prostate cancer

BACKGROUND

The molecular mechanisms involved in the prostate cancer and their relationship with immune cell infiltration are not fully understood. The prostate cancer patients undergoing standard androgen deprivation therapy eventually develop castration resistant prostate cancer (CRPC) for which there is no effective treatment currently available, and the hub genes involved in this process remain unclear.

OBJECTIVE

To study prostate cancer systematically and comprehensively.

METHODS

Differentially expressed genes (DEGs) of prostate cancer were screened in The Cancer Genome Atlas (TCGA) database. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed. Connectivity Map (Cmap) software was applied to discover potential treatment drugs. A protein-protein interaction (PPI) analysis was performed to obtained the hub genes, and the relationship between hub genes and immune cell infiltration was investigated. Next, RNAseq data of hormone-sensitive prostate cancer samples and CRPC samples obtained from TCGA database was further analyzed to identify DEGs. Finally, a PPI analysis was performed to obtain the hub genes.

RESULTS

A total of 319 DEGs were identified between prostate cancer samples and normal adjacent samples from TCGA database using comparative analysis. The KEGG pathway analysis showed significant correlations with drug metabolism, metabolism of xenobiotics by cytochrome P450, and chemical carcinogenesis. AMACR, FOLH1 and NPY, three hub genes, were found to be upregulated. FOLH1 was positively correlated with CD8+ T cell infiltration. FOLH1, AMACR, and NPY were negatively correlated with CD4+ T cell infiltration. A total of 426 DEGs were identified from RNAseq data of hormone-sensitive prostate cancer samples and CRPC samples using further comparative analysis. KEGG pathway enrichment analysis showed significant correlations with arachidonic acid metabolism, PPAR signaling pathway, AMPK signaling pathway, and metabolic pathways. The top 10 hub genes in PPI network were screened out, including PPARG, SREBF1, SCD, HMGCR, FASN, PTGS2, HMGCS2, SREBF2, FDFT1, and INSIG1. Among them, SCD and FASN are expected to be the potential therapeutic targets for CRPC.

CONCLUSIONS

AMACR, FOLH1 and NPY may be effective therapeutic targets and specific diagnostic markers for prostate cancer. AMACR, FOLH1, and NPY are also closely associated with immune cell infiltration in prostate cancer. Moreover, aminoglutethimide and resveratrol were found to be the promising drugs for treating prostate cancer. The progression of hormone-sensitive prostate cancer to CRPC may be related to arachidonic acid metabolism, PPAR signaling pathway, AMPK signaling pathway, and other metabolic pathways. SCD and FASN are expected to be the potential therapeutic targets for CRPC.

Serum Trace Elements and Their Associations with Breast Cancer Subgroups in Korean Breast Cancer Patients

The relationships between serum levels of trace elements and breast cancer remain relatively unknown. In this study, we investigate serum levels of seven trace elements in Korean breast cancer patients compared to controls without breast cancer. Serum trace element levels were determined using inductively coupled plasma mass spectrometry in Korean breast cancer patients before initiation of breast cancer treatment. Korean females without breast cancer served as a control group. Trace element levels were measured in the discovery cohort (n = 287) and were validated in an independent cohort (n = 142). We further investigated possible associations between trace element levels and the presence of lymph node metastasis, distant metastasis, or triple-negative breast cancer among breast cancer patients in subgroup analyses. Serum manganese and molybdenum levels were significantly higher (p < 0.05) in breast cancer patients than in controls. Serum copper levels were significantly higher in breast cancer patients with distant metastasis, while selenium levels were significantly lower. Other trace elements were neither significantly different between breast cancer patients and controls nor between subgroups of breast cancer patients. Our study provides insights about the potential roles and impacts of trace elements through an assessment of the associations between trace elements and breast cancer.

Selenium and breast cancer risk: A prospective nested case-control study on serum selenium levels, smoking habits and overweight

Previous research has not been conclusive regarding the association between selenium (Se) and breast cancer. This study was conducted to clarify if there is an association between prediagnostic serum Se levels and breast cancer risk. A population based cohort, the Malmö Diet and Cancer Study, was used and linked with the Swedish cancer registry up to 31 December 2013. Our study included 1,186 women with breast cancer and an equal number of controls. Selenium levels were analysed from stored serum samples. The included individuals were divided into quartiles based on Se value and we compared breast cancer cases with controls using logistic regression yielding odds ratios (OR) with 95% confidence intervals. Serum Se was also analysed as a continuous variable regarding breast cancer risk. The analyses were adjusted for established risk factors and stratified on smoking status and body mass index (BMI). When comparing the highest Se quartile with the lowest, the adjusted OR for breast cancer was 0.98 (0.75-1.26). With selenium as a continuous variable the adjusted OR was 1.00 (1.00-1.01) per 10 ng/ml. When comparing the highest with the lowest Se quartile in women with BMI > 25 kg/m² the adjusted OR was 0.77 (0.53-1.14). We conclude that it is unlikely that prediagnostic serum selenium is overall associated with breast cancer risk and no modifying effect from BMI or smoking was seen.

Selenium and Breast Cancer Risk: Focus on Cellular and Molecular Mechanisms

Selenium (Se) is a micronutrient with promising breast cancer prevention and treatment potential. There is extensive preclinical evidence of Se mammary carcinogenesis inhibition. Evidence from epidemiological studies is, however, unclear and intervention studies are rare. Here, we examine Se chemoprotection, chemoprevention, and chemotherapy effects in breast cancer, focusing on associated cellular and molecular mechanisms. Se exerts its protective actions through multiple mechanisms that involve antioxidant activities, induction of apoptosis, and inhibition of DNA damage, cell proliferation, angiogenesis, and invasion. New aspects of Se actions in breast cancer have emerged such as the impact of genetic polymorphisms on Se metabolism and response, new functions of selenoproteins, epigenetic modulation of gene expression, and long-term influence of early-life exposure on disease risk. Opportunity exists to design interventional studies with Se for breast cancer prevention and treatment taking into consideration these key aspects.

The Association Between Serum Levels of Selenium, Copper, and Magnesium with Thyroid Cancer: a Meta-analysis

There are conflicting reports on the correlation between serum levels of selenium (Se), copper (Cu), and magnesium (Mg) with thyroid cancer. The purpose of the present study is to clarify the association between Se, Cu, and Mg levels with thyroid cancer using a meta-analysis approach. We searched articles indexed in PubMed published as of January 2015 that met our predefined criteria. Eight eligible articles involving 1291 subjects were identified. Overall, pooled analysis indicated that subjects with thyroid cancer had lower serum levels of Se and Mg, but higher levels of Cu than the healthy controls [Se: standardized mean difference (SMD) = -0.485, 95% confidence interval (95%CI) = (-0.878, -0.092), p = 0.016; Cu: SMD = 2.372, 95%CI = (0.945, 3.799), p = 0.001; Mg: SMD = -0.795, 95%CI = (-1.092, -0.498), p < 0.001]. Further subgroup analysis found lower serum levels of Se in thyroid cancer in Norway [SMD = -0.410, 95%CI = (-0.758, -0.062), p = 0.021] and Austria [SMD = -0.549, 95%CI = (-0.743, -0.355), p < 0.001], but not in Poland (SMD = -0.417, 95%CI = (-1.724, 0.891), p = 0.532]. Further subgroup analysis also found that patients with thyroid cancer had higher serum levels of Cu in China [SMD = 1.571, 95%CI = (1.121, 2.020), p < 0.001] and Turkey [SMD = 0.977, 95%CI = (0.521, 1.432), p < 0.001], but not in Poland [SMD = 3.471, 95%CI = (-0.056, 6.997], p = 0.054]. In conclusion, this meta-analysis supports a significant association between serum levels of Se, Cu, and Mg with thyroid cancer. However, the subgroup analysis found that there was significant effect modification of Se, Cu levels by ethnic, like China and Poland. Thus, this finding needs further confirmation by a trans-regional multicenter study to obtain better understanding of causal relationship between Se, Cu, and Mg with thyroid cancer of different human races or regions.

Potential Health Risk of Herbal Distillates and Decoctions Consumption in Shiraz, Iran

Concentration of 26 elements in 16 different herbal distillates and 5 herbal decoctions, were determined using inductively coupled plasma-mass spectrometry (ICP-MS). The elemental content of five raw herbal materials used for making decoctions and seven distilled and boiled residues were also evaluated by inductively coupled plasma optical emission spectrometry (ICP-OES). The results indicated that herbal products display a wide range of elemental concentrations. Compared with world health regulations, the concentrations of the elements in herbal distillates and decoctions did not exceed the recommended limits. The analysis of herbal extracts did not show a significant transfer of toxic elements during decoction preparation. Comparison of elemental content among fresh herbal material and herbal distillate and decoction of the same herb showed that, besides the elemental abundance of herbal organs, the ionic potential of elements also play an important role in elemental content of herbal products. Based on the results of the research, it seems that most health benefits attributed to herbal products (especially herbal distillates) are more related to their organic compounds rather than elemental composition. Calculated hazard quotient (HQ) and hazard index (HI) were used to evaluate the noncarcinogenic health risk from individual and combined metals via daily consumption of 100 ml of herbal distillates and 250 ml of herbal decoctions. Both HQs and HI through consumption of herbal distillates and herbal decoctions (except Valerian) were below 1. Apparently, daily consumption of herbal distillates and decoctions at the indicated doses poses no significant health risk to a normal adult.

The relationship between selenium levels and breast cancer: a systematic review and meta-analysis

Breast cancer is the most common cancer type. In several studies, hints have been provided that there is a correlation between selenium deficiency and the incidence of breast cancer. Findings of these published reports are, however, inconsistent. This study serves as a pioneering study aiming at combining the results of studies using a meta-analytic method. A total of 16 articles published between 1980 and 2012 worldwide were selected through searching PubMed, Scopus, and Google scholar databases, and the information were analyzed using a meta-analytic method [random effects model]. I (2) statistics were used to examine heterogeneity. The information was then analyzed by STATA version 12. In this study, due to the non-uniform methods used to measure selenium concentrations, selenium levels were measured in the various subgroups in both case and control groups. There were significant correlations between selenium concentration and breast cancer [P<0.05]. Hence, the mean risk differentiating criteria were estimated to be 0.63 [95% confidence interval [95% CI] 0.93 to 0.32] in serum and toenails. Subgroup analysis showed that the value in toenails was -0.07 [95% CI -0.16 to 0.03] and in serum -1.04 [95% CI 1.71 to -0.38]. In studies in which selenium concentrations were measured in serum, a significant correlation was observed between selenium concentration and breast cancer. In contrast, in studies in which selenium concentration was measured in toenails, the correlation was not significant. Therefore, the selenium concentration can be used as one predictor for breast cancer.

Relationship between intensity of night shift work and antioxidant status in blood of nurses

Purpose

Light-at-night exposure can disrupt the human circadian rhythm via clock gene expressions. The circadian rhythm influences antioxidant enzymes’ activity and cellular mRNA levels of these enzymes. The employees working based on a shift system adjust to the changes occurring both on the cell level and on the level of the whole organism. Therefore, a question should be answered whether shift work disturbs oxidant–antioxidant balance and/or generates oxidative stress.

Methods

A cross-sectional study was conducted among nurses selected from the Local Registry of the Chamber of Nurses and Midwives in Lodz: 359 nurses worked daily only and 349 working rotating night shifts. These two groups differed significantly in respect of age (p < 0.0001), menopausal status (p < 0.0001), and current smoking habit (p = 0.02). The average total work duration was significantly shorter (12.4 years) in nurses working currently rotating night shifts who worked significantly longer on night shifts than day-workers (26.6 years).

Results

We found statistically significant higher red blood cell glutathione peroxidase in nurses working on night shifts (21.0 ± 4.6 vs. 20.0 ± 5.0 U/g Hb, p < 0.009) after adjusting for age, oral contraceptive hormone use, smoking, and drinking alcohol during last 24 h. Statistically significant lower vitamin A and E levels were found in the premenopausal women working in rotating system (0.690 ± 0.238 vs. 0.786 ± 0.262 μg/ml, p < 0.0001 for vitamin A and 10.93 ± 4.15 vs. 12.78 ± 4.75 μg/ml, p < 0.0001 for vitamin E). The marker of lipid peroxidation (TBARS concentration) was significantly lower in the premenopausal nurses than postmenopausal ones working day shifts only (2.06 ± 0.76 vs. 2.21 ± 0.80 nmol/ml, p < 0.038). We observed that erythrocyte GSH-Px activity rose statistically significant in nurses working more night shifts per month (p < 0.01).

Conclusions

The results quoted above seem to support the existence of an association between light-at-night exposure and blood glutathione peroxidase activity in female shift workers. Nevertheless, in order to explain the mechanisms of this association, we need more studies.

Antioxidant activity of sulfur and selenium: a review of reactive oxygen species scavenging, glutathione peroxidase, and metal-binding antioxidant mechanisms

It is well known that oxidation caused by reactive oxygen species (ROS) is a major cause of cellular damage and death and has been implicated in cancer, neurodegenerative, and cardiovascular diseases. Small-molecule antioxidants containing sulfur and selenium can ameliorate oxidative damage, and cells employ multiple antioxidant mechanisms to prevent this cellular damage. However, current research has focused mainly on clinical, epidemiological, and in vivo studies with little emphasis on the antioxidant mechanisms responsible for observed sulfur and selenium antioxidant activities. In addition, the antioxidant properties of sulfur compounds are commonly compared to selenium antioxidant properties; however, sulfur and selenium antioxidant activities can be quite distinct, with each utilizing different antioxidant mechanisms to prevent oxidative cellular damage. In the present review, we discuss the antioxidant activities of sulfur and selenium compounds, focusing on several antioxidant mechanisms, including ROS scavenging, glutathione peroxidase, and metal-binding antioxidant mechanisms. Findings of several recent clinical, epidemiological, and in vivo studies highlight the need for future studies that specifically focus on the chemical mechanisms of sulfur and selenium antioxidant behavior.