Serum selenium measurements in women with early-stage breast cancer with and without chemotherapy-induced ovarian failure

Higher Serum Selenoprotein P Level as a Novel Inductor of Metabolic Complications in Psoriasis

Selenoprotein P (SeP), a member of hepatokines, is involved in the development of various metabolic diseases closely related to psoriasis, but it has not been explored in that dermatosis so far. The study aimed to evaluate the clinical value of serum SeP concentrations in patients with psoriasis and its interplay between disease activity, metabolic or inflammatory parameters and systemic therapy. The study included thirty-three patients with flared plaque-type psoriasis and fifteen healthy volunteers. Blood samples were collected before and after three months of treatment with methotrexate or acitretin. Serum SeP levels were evaluated using the immune–enzymatic method. SeP concentration was significantly higher in patients with psoriasis than in the controls (p < 0.05). Further, in patients with severe psoriasis, SeP was significantly increased, compared with the healthy volunteers before treatment, and significantly decreased after (p < 0.05, p = 0.041, respectively). SeP positively correlated with C-reactive protein and platelets and negatively with red blood counts (p = 0.008, p = 0.013, p = 0.022, respectively). Therapy resulted in a significant decrease in SeP level. Selenoprotein P may be a novel indicator of inflammation and the metabolic complications development in psoriatics, especially with severe form or with concomitant obesity. Classic systemic therapy has a beneficial effect on reducing the risk of comorbidities by inhibiting SeP.

Absolute quantification of selenoproteins and selenometabolites in lung cancer human serum by column switching coupled to triple quadrupole inductively coupled plasma mass spectrometry

One of the most important causes of the high mortality rate and low life expectancy of lung cancer is the detection at advanced stages. Thus, there is an urgent need for early diagnosis and the search of new selective biomarkers. Selenium is an important constituent of selenoproteins and a powerful antioxidant able to protect against cancer. In this work, the absolute quantification of selenium in selenoproteins and the total content in selenometabolites has been performed for the first time in serum from lung cancer patients (LC) and healthy controls (HC). To this end, a method for the simultaneous speciation of selenoproteins using size exclusion chromatography (SEC) and affinity chromatography (AF) with detection by ICP-QQQ-MS, and quantification by isotopic dilution (IDA) (SEC-AF-HPLC-SUID-ICP-QQQ-MS) was developed to determine the selenium concentration in eGPx, SEPP1 and SeAlb, as well as total selenometabolites, to find alterations that may serve as biomarkers of this disease. In the same way, a method based on anion-exchange chromatography coupled to ICP-QQQ-MS was developed to quantify selenometabolites (SeCys2, SeMeSeCys, SeMet, selenite and selenate) in the same LC and HC serum samples. The results showed that the averaged concentrations of selenium in eGPx, SeAlb and selenite were significantly higher in LC patients (LC (eGPx: 21.24 ± 0.77 ng g^-1; SeAlb: 49.56 ± 3.16 ng g^-1 and Se(IV): 6.20 ± 1.22 ng g^-1) than in HC group (eGPx: 16.96 ± 0.53 ng g^-1; SeAlb: 38.33 ± 2.66 ng g^-1 and Se(IV): 3.56 ± 0.55 ng g^-1). In addition, the ratios between selenoproteins and selenometabolites have been calculated for the first to study their potential use as LC biomarkers. The rates eGPx/SEPP1, SEPP1/SeAlb, eGPx/Se(IV) and SEPP1/Se(IV) were significantly different between LC and HC groups.

A meta-analysis of zinc levels in breast cancer

BACKGROUND

Breast cancer is the most commonly occurring neoplasm in females, comprising 16% of all female cancers worldwide. Various studies indicate some discrepancies regarding zinc (Zn) levels in various samples of breast cancer patients.

OBJECTIVE

The present study evaluated by meta-analysed the published data for Zn levels analyzed in breast tissue, plasma, serum, and hair samples and its relationship with breast cancer.

METHODS

The present meta-analysis included 36 studies, all of which were published in the years between 1984 to 2017 and selected by searching the databases MEDLINE, EMBASE, Cochrane Library, PubMed, Scopus, and the ISI Web of Knowledge. The articles were analyzed, and I² statistics were used to examine heterogeneity. The objective analysis was performed on data from the 36 studies, with total 1699 study subjects and 2009 controls.

RESULTS

Significant statistical differences overall were observed, based on a random effects model (SMD (95 % CI), -0.78[-1.40, -0.16], P = 0.014). Data from 19 of these studies indicated significant statistical differences between cancerous patients and controls with regard to serum and plasma Zn concentration (SMD [(95 %CI): -1.61(-2.43, -0.79)]. There was a significant statistical difference between the breast tissue and hair as regards Zn status (SMD (95%CI): 2.32(1.42, 3.21)) and (SMD (95v%CI): -1.80(-3.41, -0.20), respectively. Zn concentration levels typically decreased in blood and hair samples of patients with breast cancer, whereas it was elevated in tumor tissues.

CONCLUSIONS

There is a significant relationship between lowered serum Zn concentrations and risk of breast cancer onset or recurrences in women, but because of high heterogeneity, we recommend other primary studies.

Insights into cancer and neurodegenerative diseases through selenoproteins and the connection with gut microbiota - current analytical methodologies

Introduction: Selenium plays many key roles in health especially in connection with cancer and neurodegenerative diseases. However, it needs to be appreciated that the essentiality/toxicity of selenium depends on both, a narrow range of concentration and the chemical specie involved. In this context, selenoproteins are essential biomolecules against these disorders, mainly due to its antioxidant action. To this end, analytical methodologies may allow identifying and quantifying individual selenospecies in human biofluids and tissues. Areas covered: This review focus on the role of selenoproteins in medicine, with special emphasis in cancer and neurodegenerative diseases, considering the possible link with gut microbiota. In particular, this article reviews the analytical techniques and procedures recently developed for the absolute quantification of selenoproteins and selenometabolites in human biofluids and tissues. Expert commentary: The beneficial role of selenium in human health has been extensively studied and reviewed. However, several challenges remain unsolved as discussed in this article: (i) speciation of selenium (especially selenoproteins) in cancer and neurodegenerative disease patients; (ii) supplementation of selenium in humans using functional foods and nutraceuticals; (iii) the link between selenium and selenoproteins expression and the gut microbiota and (iv) analytical methods and pitfalls for the absolute quantification of selenoproteins and selenometabolites.

Selenium status parameters in patients with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age. To date, no systematic study of interactions between selenium status parameters (SSPs: serum selenium concentration, plasma glutathione peroxidase, GPX3, plasma selenoprotein P, SELENOP), sex hormones, thyroid function parameters, and other laboratory parameters in patients with PCOS has been undertaken. Therefore we aimed to compare such parameters in women with PCOS and in the control groups, and to investigate the multidimensional interactions between various parameters in PCOS patients and in controls. The subjects were diagnosed either with PCOS (n=28, 25.4±5.2 y) or with PCOS+Hashimoto disease (n=13, 27.3±5.6 y). Female patients having normal menses were recruited into the first control group (n=70, 26.8±7.3 y) or to the second control group comprising women only with Hashimoto disease (n=10, 26.2±6.9 y). No apparent differences in SSPs between control subjects and patients with PCOS, also complicated with Hashimoto disease, were identified, though such differences were noticeable for total testosterone (tT), sex hormone binding globulin, free androgen index, dehydroepiandrosterone sulfate (DHEAS), and insulin profile. The correlation between tT and DHEAS was found the strongest. The other group of mutually highly and positively correlated parameters consisted of GPX3, follicle stimulating hormone, free triiodothyronine and free thyroxine. All the latter parameters correlated negatively with vitamin D3. SSPs took part in interactions with thyroid hormones, sex hormones and some other parameters, but only for GPX3 such interactions were statistically significant. The significance of these findings remains open for further investigation, particularly in patients with PCOS and/or Hashimoto disease.

Serum total oxidant/antioxidant status and trace element levels in breast cancer patients

BACKGROUND

Oxidative stress and trace elements have been implicated in the development of breast cancer. However, how they contribute to the pathogenesis of the disease and the relationship between them remain unclear. In addition, most previous studies detecting one or a few oxidant/antioxidant markers failed to consider the overall oxidant/antioxidant status of the subjects. This study was designed to address this and to investigate the association between oxidative status and trace elements in the pathogenesis of breast cancer.

METHODS

Fifty-six patients with breast carcinoma at different clinical stages, 32 patients with benign breast tumor, and 20 healthy subjects (controls) were recruited into this study. Their serum total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), and levels of Cu, Zn, Fe, Se, Mg, and Mn were measured.

RESULTS

Levels of TAS, TOS, OSI, and trace elements significantly differed between the study groups. Among subgroups of patients with different clinical stages of breast cancer, the levels of all the trace elements except Zn were similar, whereas TAS, TOS, and OSI levels were all significantly different. There were significant correlations between oxidative stress parameters and levels of trace elements in patients with breast carcinoma but not in patients with benign breast tumor or in the healthy controls.

CONCLUSIONS

Disturbed oxidative stress status and trace element levels may contribute to the pathogenesis of breast tumors. TAS, TOS, and OSI may be useful biomarkers for monitoring the clinical status of breast cancer.

Estrogen status alters tissue distribution and metabolism of selenium in female rats

A reported association between estrogen and selenium status may be important in the regulation of selenium metabolism. In this study, the effect of estrogen status on the metabolism of orally administered (75)Se-selenite and tissue selenium status was investigated. Female Sprague-Dawley rats were bilaterally ovariectomized at 7 weeks of age and implanted with either a placebo pellet (OVX) or pellet containing estradiol (OVX+E2), or were sham operated (Sham). At 12 weeks of age, 60 µCi of (75)Se as selenite was orally administered to OVX and OVX+E2 rats. Blood and organs were collected 1, 3, 6 and 24 h after dosing. Estrogen status was associated with time-dependent differences in distribution of (75)Se in plasma, red blood cell (RBC), liver, heart, kidney, spleen, brain and thymus and incorporation of (75)Se into plasma selenoprotein P (Sepp1) and glutathione peroxidase (GPx). Estrogen treatment also significantly increased selenium concentration and GPx activity in plasma, liver and brain, selenium concentration in RBC and hepatic Sepp1 and GPx1 messenger RNA. These results suggest that estrogen status affects tissue distribution of selenium by modulating Sepp1, as this protein plays a central role in selenium transport.

Discovery of candidate genes and pathways that may help explain fertility cycle stage dependent post-resection breast cancer outcome

Breast cancer relapse and death occur more often and sooner among young pre-menopausal women. Breast cancer resected during luteal phase cures about a quarter more women than if the operation is performed during follicular phase. We have identified candidate breast cancer gene signatures that may point to the potential mechanisms of cycle stage-dependent surgical cure. We performed whole murine genome microarrays on mammary tumors resected during pre-ovulatory (diestrus, follicular) and post-ovulatory (estrus, luteal) phases of the estrous cycle with known post-surgical cure or relapse (pulmonary metastasis) outcome. A set of genes whose expressions are differentially modulated by fertility cycle stage of tumor resection and also associate with prognosis were identified. These identified genes were validated by qRT-PCR. From two independent microarray studies, we identified 90 genes in mammary tumors whose expressions change significantly (up to 100-fold) across the estrous cycle, 69 genes that are associated with cure/relapse independent of cycle stage at resection, and 24 genes that change significantly (up to 12-fold) across the estrous cycle and also associate with the outcome. The mRNA expression patterns of these 24 identified genes were 100% validated by qRT-PCR in the same samples. We have identified candidate breast cancer genes and pathways that may point to the potential mechanisms by which the post-resection breast cancer outcome is influenced by the menstrual cycle phase of cancer resection. Since human breast cancer outcome is influenced by the menstrual cycle phase of breast cancer resection, we consider this study in a mouse breast cancer model to be a proof of principle that such signatures may well exist in human premenopausal breast cancer. It remains to be determined in human breast cancer whether woman to woman and/or tumor to tumor variability will mask cycle phase dependent and outcome predictive genomic signatures in human premenopausal breast cancer. The pathways identified by these studies are potential targets for the development of peri-surgical neoadjuvant therapies, which may delay or prevent relapse by preventing dormant micrometastatic tumor cells from escaping that dormant state post-operatively.

A distinct ERCC1 haplotype is associated with mRNA expression levels in prostate cancer patients

Both genetic variants and messenger RNA (mRNA) expression of DNA repair and tumor suppressor genes have been investigated as molecular markers for therapy outcome. However, the phenotypic impact of genetic variants often remained unclear, thus the rationale of their use in risk prediction may be limited. We therefore analyzed genetic variants together with anthropometric and lifestyle factors to see how these affect mRNA levels of ERCC1 , MDM2 and TP53 in primary blood lymphocytes. mRNA expression was measured in 376 prostate cancer patients by quantitative real-time polymerase chain reaction after reverse transcription, and ERCC1 rs11615 T>C, ERCC1 rs3212986 C>A, MDM2 rs2279744 T>G and TP53 rs17878362 (p53PIN3) polymorphisms were determined. Considerable interindividual differences in mRNA expression were found (coefficients of variation: ERCC1 , 45%; MDM2 , 43% and TP53 , 35%). ERCC1 expression was positively correlated with plasma levels of β-carotene ( P  = 0.03) and negatively correlated with canthaxanthin ( P  = 0.02) and lutein ( P  = 0.02). Overall, the polymorphisms affected mRNA expression only weakly. Carriers of a distinct ERCC1 haplotype (CC) showed, however, significantly lower expression values than non-carriers ( P  = 0.001). Applying logistic regression, we found that CC haplotype carriers had a 1.69-fold increased odds ratio (95% confidence interval: 1.06–2.71) for reduced ERCC1 mRNA levels. This low ERCC1 expression might be associated with reduced DNA repair and better therapy response. In summary, the association we have found between ERCC1 genotype and mRNA expression supports recent clinical observations that genetic variation in ERCC1 can affect treatment outcome and prognosis. Our study further revealed a modulating effect by nutritional factors.

Enhanced tight junction function in human breast cancer cells by antioxidant, selenium and polyunsaturated lipid

Paracellular permeability (PCP) is governed by tight junctions (TJs) in epithelial cells, acting as cell-cell adhesion structures, the aberration of which is known to be linked to the dissociation and metastasis of breast cancer cells. This study hypothesized that the function of TJs in human breast cancer cells can be augmented by gamma linolenic acid (GLA), selenium (Se), and iodine (I) in the presence of 17-beta-estradiol, as these molecules are known to increase TJ functions in endothelial cells, using assays of trans-epithelial resistance (TER), PCP, immunofluorescence, and in vitro invasion and motility models. GLA, I, and Se individually increased TER of MDA-MB-231 and MCF-7 human breast cancer cells. The combination of all three agents also had a significant increase in TER. Addition of GLA/Se/I reduced PCP of both breast cancer cell lines. GLA/Se/I reversed the effect of 17-beta-estradiol (reduced TER, increased PCP). Immunofluorescence revealed that after treatment with Se/I/GLA over 24 h, there was increasing relocation to breast cancer cell-cell junctions of occludin and ZO-1 in MCF-7 cells. Moreover, treatment with GLA/Se/I, alone or in combination, significantly reduced in vitro invasion of MDA-MB-231 cells through an endothelial cell barrier (P < 0.0001) and reduced 17-beta-estradiol induced breast cancer cell motility (P < 0.0001). Our previous work has demonstrated that GLA, I, and Se alone, or in combination are able to strengthen the function of TJs in human endothelial cells; this has now proved to be true of human breast cancer cells. This combination also completely reversed the effect of 17-beta-estradiol in these cells.

The anti-inflammatory effects of selenium are mediated through 15-deoxy-Delta12,14-prostaglandin J2 in macrophages

Selenium is an essential micronutrient that suppresses the redox-sensitive transcription factor NF-kappaB-dependent pro-inflammatory gene expression. To understand the molecular mechanisms underlying the anti-inflammatory property of selenium, we examined the activity of a key kinase of the NF-kappaB cascade, IkappaB-kinase beta (IKKbeta) subunit, as a function of cellular selenium status in murine primary bone marrow-derived macrophages and RAW264.7 macrophage-like cell line. In vitro kinase assays revealed that selenium supplementation decreased the activity of IKKbeta in lipopolysaccharide (LPS)-treated macrophages. Stimulation by LPS of selenium-supplemented macrophages resulted in a time-dependent increase in 15-deoxy-Delta12,14-prostaglandin J2 (15d-PGJ2) formation, an endogenous inhibitor of IKKbeta activity. Further analysis revealed that inhibition of IKKbeta activity in selenium-supplemented cells correlated with the Michael addition product of 15d-PGJ2 with Cys-179 of IKKbeta, while the formation of such an adduct was significantly decreased in the selenium-deficient macrophages. In addition, anti-inflammatory activities of selenium were also mediated by the 15d-PGJ2-dependent activation of the peroxisome proliferator-activated nuclear receptor-gamma in macrophages. Experiments using specific cyclooxygenase (COX) inhibitors and genetic knockdown approaches indicated that COX-1, and not the COX-2 pathway, was responsible for the increased synthesis of 15d-PGJ2 in selenium-supplemented macrophages. Taken together, our results suggest that selenium supplementation increases the production of 15d-PGJ2 as an adaptive response to protect cells against oxidative stress-induced pro-inflammatory gene expression. More specifically, modification of protein thiols by 15d-PGJ2 represents a previously undescribed code for redox regulation of gene expression by selenium.