Enterolactone reduces telomerase activity and the level of its catalytic subunit in breast cancer cells

Objective: There is a positive correlation between higher serum phytoestrogen concentrations and lower risk of breast cancer. The activation of telomerase is crucial for the growth of cancer cells; therefore, the aim of this study was to examine the effects of enterolactone [ENL] and enterodiol [END] on this enzyme

Materials and Methods: In this experimental study, we performed the viability assay to determine the effects of different concentrations of ENL and END on cell viability, and the effective concentrations of these two compounds on cell growth. We used western blot analysis to evaluate human telomerase reverse transcriptase catalytic subunit [hTERT] expression and polymerase chain reaction [PCR]-ELISA based on the telomeric repeat amplification protocol [TRAP] assay for telomerase activity

Results: Both ENL and END, at 100 micro M concentrations, significantly [P<0.05] reduced cell viability. However, only the 100 micro M concentration of ENL significantly [P<0.05] decreased hTERT protein levels and telomerase activity. Lower concentrations of ENL did not have any significant effects on telomerase activity and hTERT protein levels

Conclusion: High concentration of ENL decreased the viability of MCF-7 breast cancer cells and inhibited the expression and activity of telomerase in these cells. Although END could reduce breast cancer cell viability, it did not have any effect on telomerase expression and activity

Inhibition of Nicotinamide Phosphoribosyltransferase Induces Apoptosis in Estrogen Receptor-Positive MCF-7 Breast Cancer Cells / 한국유방암학회지

PURPOSE: Tumor cells have increased turnover of nicotinamide adenine dinucleotide (NAD⁺), the main coenzyme in processes including adenosine diphosphate-ribosylation, deacetylation, and calcium mobilization. NAD⁺ is predominantly synthesized in human cells via the salvage pathway, with the first component being nicotinamide. Nicotinamide phosphoribosyltransferase (NAMPT) is the key enzyme in this pathway, and its chemical inhibition by FK866 has elicited antitumor effects in several preclinical models of solid and hematologic cancers. However, its efficacy in estrogen receptor (ER)-positive and human epidermal growth factor receptor 2-positive breast cancer cells has not been previously investigated. In this study, we aimed to deplete the NAD⁺ content of MCF-7 cells, a model cell line for ER-positive breast cancer, by inhibiting NAMPT in order to evaluate downstream effects on p53 and its acetylation, p21 and Bcl-2-associated X protein (BAX) expression, and finally, apoptosis in MCF-7 breast cancer cells. METHODS: MCF-7 cells were cultured and treated with FK866. NAD⁺ levels in cells were determined colorimetrically. Levels of p53 and its acetylated form were determined by Western blotting. Expression of p21 and BAX was determined by real-time polymerase chain reaction. Finally, levels of apoptosis were assessed by flow cytometry using markers for annexin V and propidium iodide. RESULTS: FK866 treatment was able to increase p53 levels and acetylation, upregulate BAX and p21 expression, and induce apoptosis in MCF-7 cells. Addition of exogenous NAD⁺ to cells reversed these effects, suggesting that FK866 exerted its effects by depleting NAD⁺ levels. CONCLUSION: Results showed that FK866 could effectively inhibit NAD⁺ biosynthesis and induce programmed cell death in MCF-7 cells, suggesting that NAMPT inhibitors may be useful for the treatment of ER-positive breast cancers.

effects of maternal passive smoking on maternal milk lipid

Passive smoking was long overlooked by those in the medical and legal professions as being harmful to one's health, but in recent years the negative effect of passive smoking has come to the fore in the media and laws have been changed so that less people are obliged to unwillingly suffer from passive smoking, particularly in the workplace and in indoor settings. To study the effects of environmental tobacco smoking exposure during the breast-feeding period on maternal milk lipids. This cohort study was conducted on 45 mothers environmental tobacco smoking exposure and 40 non-exposed post-partum mothers referred to the Shahid Ayat health center, Tehran, Iran. Socioeconomic conditions and the demographic characteristics of exposed and non-exposed groups were recorded. Milk samples were collected twice- at baseline [5-7 days after delivery] and four months after delivery. The samples were reserved at -20°C until assay. Milk lipids including cholesterol, triglyceride [TG], high density lipoprotein [HDL] and low density lipoprotein [LDL] were evaluated. Dietary intake assessment was performed by means of the 24-hour dietary recall questionnaire both times. Maternal occupation status and education levels were significantly different between the two groups. Lipids profiles of milk were significantly higher 5-7 days after delivery in the non-exposed group and four months after delivery. Dietary intake was not significantly different between the two groups. Maternal environmental tobacco smoking exposure affects milk lipids which are essential for infant growth

Lead concentration in breast milk of lactating women who were living in Tehran, Iran

It is obvious that lead intake is of concern not for its beneficial/essential effects on metabolism, but rather for its toxic actions, which can be especially damaging to children. The objective of this study was to analyze the concentration of lead in milk of mothers during prolonged lactation. Milk samples from 43 mothers were collected at 2 months postpartum. Lead was analyzed using atomic absorption spectrophotometer. The value of lead in human milk was 23.66 +/- 22.43 micro g/l. Lead concentration in human milk of mothers was higher than other countries and no significant relationship was found between levels of human milk lead and mother's education, age, parity, height and weight. The concentrations of lead in the milk samples were high, which makes a major public health hazard for the inhabitants, especially neonatal and children, of the industrial locations

Development of a high-resolution melting method for screening R188h polymorphism in XRCC2 gene

The High Resolution Melting [HRM] method is a new scanning method for detecting unknown changes in DNA and its advantages have persuaded researchers to recruit it as a screening method. Here, we developed a HRM method to screen R188H SNP [rs3218536] of XRCC2 and compared the results with a well known PCR-RFLP technique. Genomic DNA samples from 350 healthy individuals were obtained. PCR-HRM analysis and PCR-RFLP method were performed simultaneously. Three different melting profiles corresponding to three different genotypes recognized by HRM analysis. The results of PCR-RFLP showed no discrepancy. We concluded that the HRM technique can be used as a screening method for rapid discrimination of R188H genotypes in XRCC2 gene.

Homocysteine induces heme oxygenase-1 expression via transcription factor Nrf2 activation in HepG2 cells

Background: elevated level of plasma homocysteine has been related to various diseases. Patients with hyperhomocysteinemia can develop hepatic steatosis and fibrosis. We hypothesized that oxidative stress induced by homocysteine might play an important role in pathogenesis of liver injury. Also, the cellular response designed to combat oxidative stress is primarily controlled by the transcription factor Nrf2, a principal inducer of anti-oxidant and phase II-related genes

Methods: hepG2 cells were treated with homocysteine in different time periods. Glutathione content was measured by flowcytometry. Using electrophoretic mobility shift assay [EMSA] and Western-blotting, anti-oxidant response element [ARE]-binding activity of Nrf2 for heme ocygenase-1 [HO-1] was demonstrated. Real time RT-PCR and Western-blotting were performed to evaluate whether homocysteine was able to induce mRNA and protein expression of HO-1

Results: the role of Nrf2 in cellular response to homocysteine is substantiated by the following observations in HepG2 cells exposed to homocysteine [i] Western-blotting revealed that Nrf2 is strongly stabilized and became detectable in nuclear extracts. [ii] EMSA demonstrated increased binding of Nrf2 to oligomers containing HO-1 promoter-specific ARE-binding site. [iii] Real time RT-PCR and Western-blotting revealed increased mRNA and protein expression of inducible gene HO-1 after treatment with Homocysteine

Conclusion: data presented in the current study provide direct evidence that the immediate cellular response to oxidative stress provoked by homocysteine is orchestrated mainly by the Nrf2-ARE pathway. Therefore, induction of Nrf2-ARE-dependent expression of HO-1 could be a therapeutic option for hepatic cells damage induced by homocysteine. Iran. Biomed. J. 17 [2]: 93-100, 2013

Zinc and copper concentrations in human milk and infant formulas

Available accurate data on the concentrations of copper [Cu] and zinc [Zn] in human milk throughout lactation and infant formulas is important both for formulating nutritional requirements for substances and to provide a base line for the understanding the physiology of their secretion. The objective of this study was to analyze the concentrations of zinc and copper in infant formulas and human milk during prolonged lactation. Levels of these metals were examined in relation to selected parameters such as age, weight, height, education and occupation of mothers. Thirty mothers referred to the selected clinics in Tehran entered the study. Human milk samples were collected at 2 months postpartum. Zinc and copper concentrations were determined by atomic absorption spectrophotometer. The mean values of Zn and Cu in human milk were 2.95 +/- 0.77mg/L and 0.36 +/- 0.11 mg/L. The mean values of Zn and Cu in infant formulas were 3.98 +/- 0.25 mg/L and 0.53 +/- 0.17mg/L. No significant relationship was found between levels of trace elements in human milk and evaluated parameters such as age, weight, height, education and occupation of mothers. The concentrations of zinc and copper in breast milk were lower than those reported in the literature

Effect of progesterone-only contraception on vitamin D in human milk

Nowadays progesterone contraceptives are being used by lactating women. In the last century elements effective in bone growth in infants, such as calcium, phosphorus and vitamin D have been evaluated. Vitamin D has been mentioned mainly in relation to rickets prevention in infants. This study was initiated in order to investigate the effect of Progestin-only contraceptives on breast milk vitamin D. In this cohort study 138 lactating women were assigned to either the hormonal [52 participants] or non-hormonal [86 participants] groups according to their chosen method of contraception. The characteristics and goals of the study were explained in detail and informed consent was obtained from all subjects before inclusion in the study. Research units started their method of contraception 45 [7] days postpartum and continued at least for 6 months afterward. 10 ml milk samples were obtained before the baby nursed at 6 mos postpartum, and kept at -20 °C until analysis. Vitamin D levels were measured with RIA method. Vitamin D levels were found to be 11.2 [7.2] nmol/L in the hormonal and 10.67 +/- 6.6 nmol/L in the non-hormonal groups, which was lower than other cultures. There was not a significant difference between the vitamin D levels of the two groups statistically [P>0.05]. According the results, the consumption of progesterone-only contraceptives had no effect on the vitamin D levels of mothers' milk, although with regard to low levels of vitamin D in the milk of lactating mothers, it is necessary to enrich foods with vitamin D and for mothers to use vitamin D supplements