洛伐他汀对MCF-7细胞pRb蛋白表达及增殖功能的影响

目的探讨洛伐他汀(Lovastatin)影响MCF7乳腺癌细胞增殖功能的可能机制。方法采用生长曲线,NBT还原实验,逆转录PCR检测RbmRNA和western blotting分析Rb蛋白表达等实验技术。结果不同剂量的Lovastatin均可抑制MCF7细胞增殖能力并促进细胞的分化;Lovastatin处理48h和72h后RbmRNA较未处理组细胞表达增强;处理48h后pRb蛋白表达随剂量的增加而逐渐减弱,而72h后各处理组pRb蛋白表达均明显低于未处理组,且同剂量组间处理72hpRb蛋白表达明显低于48h的处理组。结论Lovastatin可能通过作用于细胞周期进程中RbmRNA合成及其蛋白的表达,来促进MCF7乳腺癌细胞的分化。     

Antiestrogenic Effects of Motorcycle Exhaust Particulate in MCF-7 Human Breast Cancer Cells and Immature Female Rats

The emissions from 2- and 4-stroke motorcycles pollute the air of urban areas where motorcycle is a popular means of transportation. This study aimed to determine the endocrine-disrupting activity of motorcycle exhaust particulate (MEP) using MCF-7 human breast cancer cells and immature female Wistar rats treated with organic extracts of MEP. Treatments with 1, 10, and 50 g/ml MEP extract for 2 and 4 days produced dose-dependent inhibition of thymidine incorporation and cell growth, respectively, in untreated and 1 nM 17-estradiol (E₂)-treated cells. Treatments of MCF-7 cells with MEP extract replaced [³H]E₂ from the estrogen receptor in a time- and concentration-dependent manner. These antiestrogenic and receptor binding properties of MEP extract were blocked by cotreatment of the cells with 2 M -naphthoflavone, a cytochrome P450 inhibitor and aryl hydrocarbon receptor antagonist. E₂ metabolism and HPLC analysis showed that treatment of MCF-7 cells with 50 g/ml MEP extract for 24 h increased E₂ 2- and 4-hydroxylation in microsomes. The MEP-mediated increase in E₂ 2-hydroxylation was inhibited by the addition of 1 M -naphthoflavone to MCF-7 microsomes. Cotreatment of immature female rats with 10 g/kg E₂ and 10 mg/kg MEP extract intraperitoneally for 3 days decreased the E₂-induced uterine weights. MEP extract alone showed no effect on rat uterine weight. The endocrine-disrupting activity of MEP extract was further confirmed in parallel experiments using MCF-7 cells and immature female rats treated with benzo(a)pyrene, an MEP constituent compound. The present findings demonstrate that MEP extract is antiestrogenic in vitro and in vivo and cytochrome P450 induction is an underlying mechanism.     

Exposure to Endocrine-Disrupting Chemicals during Pregnancy and Weight at 7 Years of Age: A Multi-pollutant Approach

Background

Prenatal exposure to endocrine-disrupting chemicals (EDCs) may induce weight gain and obesity in children, but the obesogenic effects of mixtures have not been studied.

Objective

We evaluated the associations between pre- and perinatal biomarker concentrations of 27 EDCs and child weight status at 7 years of age.

Methods

In pregnant women enrolled in a Spanish birth cohort study between 2004 and 2006, we measured the concentrations of 10 phthalate metabolites, bisphenol A, cadmium, arsenic, and lead in two maternal pregnancy urine samples; 6 organochlorine compounds in maternal pregnancy serum; mercury in cord blood; and 6 polybrominated diphenyl ether congeners in colostrum. Among 470 children at 7 years, body mass index (BMI) z-scores were calculated, and overweight was defined as BMI > 85th percentile. We estimated associations with EDCs in single-pollutant models and applied principal-component analysis (PCA) on the 27 pollutant concentrations.

Results

In single-pollutant models, HCB (hexachlorobenzene), βHCH (β-hexachlorocyclohexane), and polychlorinated biphenyl (PCB) congeners 138 and 180 were associated with increased child BMI z-scores; and HCB, βHCH, PCB-138, and DDE (dichlorodiphenyldichloroethylene) with overweight risk. PCA generated four factors that accounted for 43.4% of the total variance. The organochlorine factor was positively associated with BMI z-scores and with overweight (adjusted RR, tertile 3 vs. 1: 2.59; 95% CI: 1.19, 5.63), and these associations were robust to adjustment for other EDCs. Exposure in the second tertile of the phthalate factor was inversely associated with overweight.

Conclusions

Prenatal exposure to organochlorines was positively associated with overweight at age 7 years in our study population. Other EDCs exposures did not confound this association.

Citation

Agay-Shay K, Martinez D, Valvi D, Garcia-Esteban R, Basagaña X, Robinson O, Casas M, Sunyer J, Vrijheid M. 2015. Exposure to endocrine-disrupting chemicals during pregnancy and weight at 7 years of age: a multi-pollutant approach. Environ Health Perspect 123:1030–1037; http://dx.doi.org/10.1289/ehp.1409049     

Estrogenic Effects of Cimicifuga racemosa (Black Cohosh) in Mice and on Estrogen Receptors in MCF-7 Cells

The estrogenic effects of Cimicifuga racemosa or Actacea racemosa (black cohosh, CR) extracts were tested in mice, and their effects on estrogen receptor (ER) levels in human breast cancer MCF-7 cells were also investigated. Four groups of weanling female Kunming mice were given 0 (control), 75, 150, or 300 mg/kg body weight CR extracts orally for 14 days. The estrus cycle and the weights of the uterus and ovary of mice, as well as serum estradiol (E(2)) were measured. The proliferation patterns of MCF-7 cells exposed to CR extracts or 17beta-estradiol were studied by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Subsequently, growth of MCF-7 cells in 0 (control) or 4.75 &mgr;g/L of CR extracts or 0.3 nmol/L of 17beta-estradiol groups were observed for 5 days. ER levels in MCF-7 cells were analyzed by indirect immunofluorescence assay using flow cytometry. The uterine weights of mice increased with the increase in dosage of CR extracts, and the estrus duration was significantly prolonged in the group receiving 300 mg/kg body weight (P <.05). However, CR extracts did not increase the serum E(2) concentration significantly. In the in vitro study, a dose-response relationship was demonstrated when cells were treated with low doses of CR extracts, and the optimal enhancement concentration of CR extracts was 4.75 &mgr;g/L on MCF-7 cells. The doubling times (T(D)) of cell growth in the CR extracts group and the 17beta-estradiol group were 32.1 and 31.7 hours, respectively, both shorter than that of the negative control group (T(D) = 35.3 hours). Additionally, 4.75 &mgr;g/L of CR extracts resulted in significantly increased ER levels compared with the control group (P <.01). In conclusion, CR extracts produced an estrogenic action. The effect of increasing ER levels by CR extracts may be one of the potential mechanisms of its phytotherapeutic effects for postmenopausal symptoms.     

某化纤厂接触不同浓度二硫化碳的工人血糖血脂检出水平

[目的]研究二硫化碳(CS2)暴露对作业工人血糖(glucose,GLU)、总胆固醇(total cholesterol,TCHO)和三酰甘油(triglyceride,TG)检出水平的影响,并提出职业健康监护行动水平的建议。[方法]收集某化纤厂2004—2011年间工作场所CS2浓度或作业工人个体接触CS2浓度的检测资料,对该化纤厂3 456名接触CS2的作业工人分别进行GLU、TCHO和TG水平的检查。[结果]该化纤厂作业工人接触CS2的8 h时间加权平均浓度为0.2~41.0 mg/m3,几何均数为2.38 mg/m3。其中1 758名作业工人接触CS2的浓度在0.2~2.5 mg/m3之间(A组);653名作业工人接触CS2的浓度在2.6~4.8 mg/m3之间(B组);1 045名作业工人接触CS2的浓度在5.1~41.0 mg/m3之间(C组)。男性C浓度组高TG检出率高于A、B两浓度组,差异有统计学意义(P<0.05);A、B浓度组之间差异无统计学意义(P>0.05)。男性高GLU、高TCHO检出率及女性高GLU、高TCHO和高TG检出率在不同浓度组中差异均无统计学意义(P>0.05)。各年龄段C浓度组高TG检出率高于A、B两浓度组;A、B浓度组间差异无统计学意义(P>0.05)。不同浓度组间高GLU和高TCHO检出率差异无统计学意义(P>0.05)。男性不同累积接触量组间高TG检出率差异有统计学意义(P<0.01);高GLU和高TCHO检出率差异无统计学意义(P>0.05)。女性不同累积接触量组间高GLU、高TCHO和高TG检出率差异无统计学意义(P>0.05)。[结论]男性作业工人接触CS2浓度>5 mg/m3或累积接触量>50 mg/(m3·年)时,可使高TG检出率明显升高。在对CS2作业工人进行职业健康监护时,宜执行CS2时间加权平均浓度为2.5 mg/m3(职业接触限值的1/2)的行动水平,并加强对累积接触量>50 mg/(m3·年)的作业工人的健康检查。     

Analysis of Selenium Levels in Osteosarcoma Patients and the Effects of Se-Methylselenocysteine on Osteosarcoma Cells In Vitro

The form of selenium appears to be important for preventing cancer in humans. Here, we evaluated selenium levels in the serum and bone tissue samples from osteosarcoma patients using atomic absorption spectrometry. The in vitro effects of Se-methylselenocysteine (Se-MSC) on growth, cell cycle status, and apoptosis of osteosarcoma cells were assessed using the WST-1 assay, Hoechst 33342/propidium iodide staining, and flow cytometry, respectively. In osteosarcoma cases, the mean serum selenium levels in osteosarcoma tissue and normal bone were 0.08 mg/kg and 0.03 mg/kg, respectively (P < 0.05). Serum selenium levels in osteosarcoma and non-osteosarcoma cases were 0.09 mg/L and 0.08 mg/L, respectively (P > 0.05). Se-MSC-treated MG63 cells showed altered cellular morphology, decreased viability in a time- and dose-dependent manner, and an increase in the sub-G₁ cell population. Se-MSC also downregulated Bcl-2 expression and upregulated Bax. Se-MSC inhibited the proliferation of the drug-resistant osteosarcoma cell line Saos-2/MTX300 and enhanced the inhibitory effect of pirarubicin on MG63 cells. Our data demonstrate that selenium levels are significantly higher in osteosarcoma tissue than normal bone tissue in osteosarcoma patients. The results also support the anticancer effects of Se-MSC in osteosarcoma. Further development of Se-MSC as an ancillary chemotherapy agent in osteosarcoma is warranted.     

UGT2B7基因多态性与联苯胺职业暴露工人尿脱落细胞巴氏分级结果的关系

[目的]研究UGT2B7基因多态性与联苯胺职业暴露工人尿脱落细胞巴氏分级(PG)结果之间的关系。[方法]选取上海市染料化工行业职业性联苯胺接触队列中2003年接受膀胱癌医学监护的成员248人为对象,应用聚合酶链反应.限制性片段长度多态性(PCR-RFLP)检测UGT2B7基因型;用巴氏分级法对尿脱落细胞进行分级。[结果]PG>Ⅱ组和PG≤Ⅱ组的UGT2BT*1/*1(CC)基因型携带者的比率分别为54.9%和48.0%(P>0.05)。两组人群UGT2B7各基因型的分布频率也未见显著性差异(P>0.05)。[结论]UGT2B7基因多态性形态对联苯胺暴露工人PG升高的风险可能没有影响。     

银杏黄酮类对实验性染铅大鼠血铅、GSH及SOD水平的影响

铅对婴幼儿及儿童的危害远远高于成人，其主要表现在脑发育期低水平接触铅导致中枢神经系统不可逆能障碍。 近年来，铅的氧化性损伤机理引起了人们的关注，据报导铅可破坏机体氧化抗氧化平衡，导致自由基产生增加；抑制抗氧化性非酶和酶系统的活性，导致机体氧化性损伤。文献报道银杏黄酮类具有强的抗氧化功能，本实验旨在观察银杏黄酮类化合物对染铅大鼠的血铅、SOD和GSH水平的影响，为防治铅中毒提供实验依据。     

Human Cell Line Toxicity of Binary and Ternary Chemical Mixtures in Comparison to Individual Toxic Effects of Their Components

Contaminated site projects involve health risk assessment procedures that must consider potential interactive effects of present contaminants. In order to establish a quick and reliable method that accounts for smaller than additive, additive, or greater than additive toxic effects, this study compared the cytotoxicity of 34 binary and ternary chemical mixtures of four structurally different chemicals to HeLa cells. Further, five blind samples of these mixtures or their components were tested to determine the ability to identify unknown mixtures. The colorimetric MTS in vitro cytotoxicity assay was used to detect cytotoxic effects after the cells were exposed for 1 h to serial dilutions of the mixtures. Experimental cytotoxicity data were compared and set against data predicted by a mathematical algorithm. They mainly showed additive effects of the components in mixture but also identified smaller than additive and greater than additive effects. A subjective classification scheme allowed evaluation of the toxicity of the blind samples in comparison to results from the study on binary and ternary mixtures tested before. This scheme focused on quantitative cytotoxicity data as well as on the slope of the concentration-effect curves and demonstrated the use of the MTS assay for human health risk assessments in the context of contaminated sites. Received: 15 October 1997/Accepted: 22 February 1998     

Cardiovascular Depression in Rats Exposed to Inhaled Particulate Matter and Ozone: Effects of Diet-Induced Metabolic Syndrome

Background: High ambient levels of ozone (O₃) and fine particulate matter (PM_2.5) are associated with cardiovascular morbidity and mortality, especially in people with preexisting cardiopulmonary diseases. Enhanced susceptibility to the toxicity of air pollutants may include individuals with metabolic syndrome (MetS).Objective: We tested the hypothesis that cardiovascular responses to O₃ and PM_2.5 will be enhanced in rats with diet-induced MetS.Methods: Male Sprague-Dawley rats were fed a high-fructose diet (HFrD) to induce MetS and then exposed to O₃, concentrated ambient PM_2.5, or the combination of O₃ plus PM_2.5 for 9 days. Data related to heart rate (HR), HR variability (HRV), and blood pressure (BP) were collected.Results: Consistent with MetS, HFrD rats were hypertensive and insulin resistant, and had elevated fasting levels of blood glucose and triglycerides. Decreases in HR and BP, which were found in all exposure groups, were greater and more persistent in HFrD rats compared with those fed a normal diet (ND). Coexposure to O₃ plus PM_2.5 induced acute drops in HR and BP in all rats, but only ND rats adapted after 2 days. HFrD rats had little exposure-related changes in HRV, whereas ND rats had increased HRV during O₃ exposure, modest decreases with PM_2.5, and dramatic decreases during O₃ plus PM_2.5 coexposures.Conclusions: Cardiovascular depression in O₃- and PM_2.5-exposed rats was enhanced and prolonged in rats with HFrD-induced MetS. These results in rodents suggest that people with MetS may be prone to similar exaggerated BP and HR responses to inhaled air pollutants.Citation: Wagner JG, Allen K, Yang HY, Nan B, Morishita M, Mukherjee B, Dvonch JT, Spino C, Fink GD, Rajagopalan S, Sun Q, Brook RD, Harkema JR. 2014. Cardiovascular depression in rats exposed to inhaled particulate matter and ozone: effects of diet-induced metabolic syndrome. Environ Health Perspect 122:27–33; http://dx.doi.org/10.1289/ehp.1307085     

Joint Toxicity of Similarly and Dissimilarly Acting Chemicals to <Emphasis Type="Italic">Daphnia magna</Emphasis> at Different Response Levels

The toxicity of two amines, nonylamine and decylamine, which have a narcotic effect on organisms, and ethylparathion (enzymatic inhibitor) on Daphnia magna has been studied when acting singly and in joint toxicity tests. This was done on the basis of an isobologram method where curves of constant response, i.e., isoboles are plotted vs. the concentrations of the two toxicants. The concentrations that immobilized 50, 10, and 0% of the test population in 48 h (IC50-48h, IC10-48h, and IC0-48h) were calculated. It is shown that nonylamine–decylamine mixtures follow a near concentration addition model of joint toxicity, while ethylparathion–decylamine mixtures follow a less than additive or near independent action model. The study was performed using three toxicity indices: additive index, sum of toxic units, and similarity parameter . An analysis of the similarity parameter is done to evaluate whether it has a constant value for IC50-48h, IC10-48h, and IC0-48h. The results suggest that it is quite probable that a constant value of can be used to characterize all response levels, as the isoboles corresponding to the average value of the similarity parameter fit within the 95% confidence intervals of toxicant concentrations at all response levels. The average value of is about 0.80 for the nonylamine–decylamine test and 0.30 for the ethylparathion–decylamine test.     

The Effects of Choline on Hepatic Lipid Metabolism,Mitochondrial Function and Antioxidative Status in Human Hepatic C3A Cells Exposed to Excessive Energy Substrates

Choline plays a lipotropic role in lipid metabolism as an essential nutrient. In this study, we investigated the effects of choline (5, 35 and 70 μM) on DNA methylation modifications, mRNA expression of the critical genes and their enzyme activities involved in hepatic lipid metabolism, mitochondrial membrane potential (Δψm) and glutathione peroxidase (GSH-Px) in C3A cells exposed to excessive energy substrates (lactate, 10 mM; octanoate, 2 mM and pyruvate, 1 mM; lactate, octanoate and pyruvate-supplemented medium (LOP)). Thirty five micromole or 70 μM choline alone, instead of a low dose (5 μM), reduced hepatocellular triglyceride (TG) accumulation, protected Δψm from decrement and increased GSH-Px activity in C3A cells. The increment of TG accumulation, reactive oxygen species (ROS) production and Δψm disruption were observed under LOP treatment in C3A cells after 72 h of culture, which were counteracted by concomitant treatment of choline (35 μM or 70 μM) partially via reversing the methylation status of the peroxisomal proliferator-activated receptor alpha (PPARα) gene promoter, upregulating PPARα, carnitine palmitoyl transferase-I (CPT-I) and downregulating fatty acid synthase (FAS) gene expression, as well as decreasing FAS activity and increasing CPT-I and GSH-Px activities. These findings provided a novel insight into the lipotropic role of choline as a vital methyl-donor in the intervention of chronic metabolic diseases.     

Arsenic Bioaccumulation and Biotransformation in Clams (Asaphis violascens) Exposed to Inorganic Arsenic: Effects of Species and Concentrations

Bulletin of Environmental Contamination and Toxicology - High arsenic (As) concentrations are found in marine clams, usually as less-toxic arsenobetaine (AsB). However, when clams were exposed to...