Systemic Essential Metal and Metalloid Levels in Patients with Benign Breast Disease and Breast Cancer.

The objective of the present study is evaluation of serum and hair levels of essential metals and metalloids in women with benign breast disease and breast cancer in order to define similar and distinct patterns that may mediate the link between these pathologies. A total of 310 adult women aged 20-80 years old were enrolled in the present study. Of those, 103 patients had benign (fibrocystic) breast disease, 107 patients had breast cancer (stage II), and 100 women were healthy and with absence of breast pathology. Trace metal and metalloid levels in hair and serum were evaluated by inductively coupled argon plasma mass-spectrometry (ICP-MS). The data demonstrate that breast cancer patients were characterized by significantly higher hair Cr and V levels, as well as reduced Cu and Mn content as compared to both benign breast disease patients and controls. In contrast, serum Cu levels in women with breast cancer exceeded those in the controls and benign breast disease cases. Patients with both benign and malignant breast tumors were characterized by lower serum Mn levels as compared to the control values. Serum Cu/Zn and especially Cu/Mn were found to be significantly increased in cancer patients. Significantly reduced hair and serum Se levels were noted only in women with fibrocystic disease. Based on the analysis of two biosamples, it is proposed that malignant breast tumor development is associated with the reduction of systemic Mn and Zn levels, and a concomitant elevation of Cu concentrations.

Alterations in serum amino acid profiles in children with attention deficit/hyperactivity disorder.

The objective of the present study was to evaluate the circulating serum amino acid levels in children with attention deficit/hyperactivity disorder (ADHD). A total of 71 children with untreated ADHD and 31 neurotypical controls aged 7-14 years old were examined. Serum amino acid levels were evaluated using high-performance liquid chromatography (HPLC) with UV-detection. Laboratory quality control was performed with reference materials of human plasma amino acid levels. The obtained data demonstrated that children with ADHD were characterized by 29, 10 and 20% lower serum histidine (His), glutamine (Gln) and proline (Pro) levels compared with neurotypical children, respectively. In contrast, circulating aspartate (Asp), glutamate (Glu) and hydroxyproline (Hypro) levels exceeded the respective control values by 7, 7 and 42%. Correspondingly, the Gln-to-Glu and Pro-to-Hypro ratios were 28% and 49%, respectively, lower in ADHD cases compared with the controls. Total Gln/Glu levels were also significantly lower in ADHD patients. No significant group differences were observed between the groups in the other amino acids analyzed, including phenylalanine. Multiple linear regression analysis revealed significant associations between circulating serum Gln, lysine (Lys) (both negative) and Glu (positive) levels with total ADHD Rating Scale-IV scores. The observed alterations in Pro/Hypro and Gln/Glu levels and ratios are likely associated with the coexisting connective tissue pathology and alterations in glutamatergic neurotransmission in ADHD, respectively. Altered circulating levels of His, Lys and Asp may also be implicated in ADHD pathogenesis. However, further in vivo and in vitro studies are required in order to investigate the detailed mechanisms linking amino acid metabolism with ADHD pathogenesis.

Serum levels of copper, iron, and manganese in women with pregnancy, miscarriage, and primary infertility.

BACKGROUND: Iron (Fe), copper (Cu), and manganese (Mn) play a significant role in female reproduction and fetal development. At the same time, high levels of metals may exert toxic effects. Correspondingly, both excess and deficiency of essential trace elements were shown to be associated with female infertility and adverse pregnancy outcome, although the existing data are rather contradictory. Therefore, the objective of the present study was to reveal the potential role of altered iron, copper, and manganese status in female reproductive health problems through assessment of serum metal levels in healthy non-pregnant and pregnant women, as well as patients with miscarriage and primary infertility. METHODS: A total of 150 healthy controls, 169 pregnant women (II trimester of pregnancy), 75 women with miscarriage, and 91 patients with primary infertility were enrolled. Serum metal levels were assessed using ICP-MS. RESULTS: Pregnant women are characterized by a significant increase in serum Cu an Mn levels by 40% (p < 0.001) and 16% (p = 0.043) as compared to the controls, respectively. Serum Cu levels in women with miscarriage and infertility were 30% and 35% lower than those in pregnant women (p < 0.001). No significant difference in serum iron levels were observed between the control and pregnant women. Women who had miscarriage were characterized by 13% (p = 0.042) higher serum Fe levels as compared to the pregnant ones. Multiple regression analysis demonstrated that serum copper levels was significantly associated both with pregnancy (ß = 0.436; p < 0.001) and reproductive health problems in women (ß = -0.272; p < 0.001). The latter was improved significant after adjustment for serum Fe and Mn levels, age, and BMI (ß = -0.431; p < 0.001). The model incorporating serum Cu, Fe, Mn, and anthropometric parameters accounted for 23% of variability in reproductive status (p < 0.001). CONCLUSIONS: It is proposed that the lack of pregnancy-associated increase in metal levels in miscarriage and infertility may be indicative of at least partial role of metal insufficiency in impaired pregnancy and reproductive function in general. However, detailed clinical studies as well as experimental investigations are required for assessment of the potential causes and mechanisms of the observed associations.

Comparative effects of meso-2,3-dimercaptosuccinic acid, monensin and salinomycin on the concentrations of cadmium and some essential elements in skeletal muscles of Cd-exposed mice.

Cadmium (Cd) is an environmental pollutant shown to induce multi organ dysfunction. In this study we present novel data about the effects of meso-2,3-dimercaptosuccinic acid (DMSA), monensin and salinomycin on the concentration of Cd in skeletal muscles of mice exposed to Cd (II) acetate treatment for 14 days. The impact of Cd and the chelating agents on the endogenous concentrations of calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), phosphorous (P), selenium (Se) and zinc (Zn) was also investigated. Subacute exposure of mice to Cd (II) acetate resulted in a significant accumulation of the toxic metal ion in the skeletal muscles compared to the untreated controls. Salinomycin most effectively mobilized Cd from the muscles compared to DMSA and monensin. The Cd exposure and the tested chelating agents did not significantly alter the endogenous concentrations of the selected essential elements in mouse muscles. The presented results confirmed that among the tested chelating agents salinomycin is superior as a potential antidote to Cd poisoning.

Hair concentration of essential trace elements in adult non-exposed Russian population.

Appropriate reference values of hair trace element content are required for correct interpretation of biomonitoring data. The primary objective of the current study was to estimate the reference values of selected essential trace elements in hair of adult Russian population. Involved in current investigation were 7256 occupationally non-exposed adults aged from 20 to 60 years and living in the European part of Russia. Occipital hair essential metal and metalloid (Co, Cr, Cu, Fe, Mn, Se, V, Zn) content was estimated using inductively coupled plasma mass spectrometry. The reference ranges were calculated in accordance with the International Union of Pure and Applied Chemistry (IUPAC) recommendations. Women were characterized by 55, 18, 58, and 7% higher values of hair Co, Cu, Mn, and Zn content as compared to the values observed in men. At the same time, hair Cr, Fe, Se, and V concentration in men significantly exceeded the respective female values by 65, 13, 20, and 56%. Consequently, the reference ranges of essential hair trace elements content should be separately calculated for both men and women. The obtained reference ranges for hair Co, Cr, Cu, Fe, Mn, Se, V, and Zn in men were 0.11-0.67, 0.007-0.045, 10.4-22.6, 11.1-40.5, 0.24-1.05, 0.089-0.480, 0.014-0.083, and 125.7-262.8 µg/g, respectively. The respective values estimated for women were 0.06-0.40, 0.011-0.085, 12.1-44.5, 8.9-25.6, 0.32-2.05, 0.094-0.504, 0.010-0.056, and 140.0-315.1 µg/g. The reference ranges for hair Co (0.07-0.50), Cr (0.009-0.073), Cu (11.8-29.2), Fe (9.6-31.5), Mn (0.29-1.76), Se (0.093-0.482), V (0.011-0.069), and Zn (134.7-301.9) content (µg/g) in the general cohort were also calculated.

Reference values of hair toxic trace elements content in occupationally non-exposed Russian population.

A total of 5908 occupationally non-exposed adults (4384 women and 1524 men) living in Moscow and Moscow region were involved in the current investigation. Hair Al, As, Be, Bi, Cd, Hg, Li, Ni, Pb, Sn, and Sr content was estimated by inductively-coupled plasma mass spectrometry using NexION 300D. Men are characterized by significantly higher hair Al, As, Cd, Hg, Li, and Pb content. At the same time, hair levels of Bi, Ni, Sn, and Sr were significantly higher in women. Consequently, the reference ranges were estimated for male, female, and general cohort as coverage intervals in accordance with IUPAC recommendations.

Oestrogen treatment enhances the sensitivity of hormone-resistant breast cancer cells to doxorubicin.

Recently, it was shown that the resistance of breast cancer cells to growth-stimulating oestrogen action may be accompanied with the paradoxical tumour sensitization to oestrogen apoptotic action. In the present paper, we studied the influence of oestrogens on the sensitivity of resistant breast tumours to cytostatic drugs, and to evaluate the role of NF-κB (nuclear factor κB) signalling in the regulation of the apoptotic response of the resistant cells. The experiments were carried out on the oestrogen-dependent MCF-7 breast cancer cells and resistant MCF-7/LS subline generated through long-term cultivation of the parental cells in the absence of oestrogen. The cell treatment with the combination of oestradiol and Dox (doxorubicin) was found to enhance the apoptotic action of Dox in MCF-7/LS cells but not in the parent cells. MCF-7/LS cells were characterized by the increased level of ROS (reactive oxygen species) and decreased NF-κB activity. Oestradiol in combination with Dox leads to significant NF-κB stimulation and its accumulation in the nucleus of MCF-7/LS cells. The knockdown of NF-κB with siRNA (small interfering RNA) increased the apoptotic response of the MCF-7/LS cells to both Dox and oestradiol demonstrating the important role of NF-κB in the protection of the MCF-7/LS cells against apoptosis. In general, the results obtained show that: (i) oestradiol enhances the apoptotic action of Dox in the resistant breast cancer cells; and (ii) suppression of NF-κB signalling amplifies the apoptotic response of the resistant cells to both oestrogen and Dox, demonstrating that NF-κB may serve as a potential target in the therapy of the resistant breast cancer.

The breast cancer cells response to chronic hypoxia involves the opposite regulation of NF-kB and estrogen receptor signaling.

The progression of cancer is associated with tumor's ability to outgrow the existing vasculature resulting in chronic hypoxic pressure, however the molecular mechanism of cancer cell response to chronic hypoxia is poorly understood. In this study we have analyzed the reorganization of estrogen receptor (ER) signaling in breast cancer cells under chronic hypoxia and examined the role of interrelations between ER and NF-kB signaling in cell adaptation to hypoxia. Using long-term culturing of MCF-7 breast cancer cells in hypoxia-mimetic conditions (cobalt chloride) we have established a hypoxia-tolerant subline characterized by HIF-1 hyperexpression that retained the tolerance to hypoxia even when the cells were returned to normoxic conditions. The hypoxia-tolerant cells were characterized by non-affected ER signaling, irreversible suppression of NF-kB activity, and increased sensitivity to cytokine-induced apoptosis. Estradiol treatment suppressed the NF-kB activity in both parent and hypoxia-tolerant MCF-7 cells. In contrast to MCF-7 cells, the exposure of estrogen-independent MCF-7/T2 subline to chronic hypoxia was not accompanied by noticeable changes in NF-kB activity or cell sensitivity to cytokines. Taken together, the results presented demonstrate the importance of interrelations between ER and NF-kB signaling in the response of estrogen-dependent breast cancer cells to chronic hypoxia.

Activation of mitogenic pathways and sensitization to estrogen-induced apoptosis: two independent characteristics of tamoxifen-resistant breast cancer cells?

Paradoxical induction of apoptosis by estrogen has been described previously for estrogen-deprived and antiestrogen-resistant breast cancer cells. In this study we analyzed the possible interrelations between cell sensitization to estrogen apoptotic action and cell ability to (anti)estrogen-independent growth. Using tamoxifen-resistant sublines derived from the parent MCF-7 breast cancer cells by long-term tamoxifen treatment we demonstrated that resistant cells are characterized by increased level of EGF receptor and unexpected increase of VEGF receptor 2 (Flk-1/KDR) and its specific ligand, VEGF-A. The importance of the VEGF signaling in the autocrine regulation of cell growth was indicated by the ability of VEGF inhibitor, soluble fragment of Flt-1/Fc chimera, to suppress the phosphorylation of MAP kinases as well as to inhibit the estrogen-independent growth of MCF-7 cells. Sensitization of tamoxifen-resistant cells to estrogen-induced apoptosis required the additional continuous cultivation in steroid-depleted medium and did not depend on the activity of both EGF and VEGF pathways. Finally, we showed that treatment of the cells with 17beta-estradiol (10(-9) M) resulted in a marked increase in p53 level both in the resistant cells undergoing apoptosis and in the parent MCF-7 cells insensitive to apoptotic estrogen action. These data provide an important support for the existence of a disbalance between pro- and anti-apoptotic machinery in the resistant breast cancer cells that forms independently of the acquired ability to estrogen-independent growth.