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1.
Folic acid supplementation enhances arsenic methylation: results from a folic acid and creatine supplementation randomized controlled trial in Bangladesh.
Bozack, AK, Hall, MN, Liu, X, Ilievski, V, Lomax-Luu, AM, Parvez, F, Siddique, AB, Shahriar, H, Uddin, MN, Islam, T, et al
The American journal of clinical nutrition. 2019;(2):380-391
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Abstract
BACKGROUND Arsenic exposure through drinking water persists in many regions. Inorganic As (InAs) is methylated to monomethyl-arsenical species (MMAs) and dimethyl-arsenical species (DMAs), facilitating urinary excretion. Arsenic methylation is dependent on one-carbon metabolism, which is influenced by nutritional factors such as folate and creatine. OBJECTIVE This study investigated the effects of folic acid (FA) and/or creatine supplementation on the proportion of As metabolites in urine. DESIGN In a 24-wk randomized, double-blinded, placebo-controlled trial, 622 participants were assigned to receive FA (400 or 800 μg per day), 3 g creatine per day, 400 μg FA + 3 g creatine per day, or placebo. The majority of participants were folate sufficient; all received As-removal water filters. From wk 12-24, half of the participants receiving FA received placebo. RESULTS Among groups receiving FA, the mean decrease in ln(%InAs) and %MMAs and increase in %DMAs exceeded those of the placebo group at wk 6 and 12 (P < 0.05). In the creatine group, the mean decrease in %MMAs exceeded that of the placebo group at wk 6 and 12 (P < 0.05); creatine supplementation did not affect change in %InAs or %DMAs. The decrease in %MMAs at wk 6 and 12 was larger in the 800 µg FA than in the 400 µg FA group (P = 0.034). There were no differences in treatment effects between the 400 µg FA and creatine + FA groups. Data suggest a rebound in As metabolite proportions after FA cessation; at wk 24, log(%InAs) and %DMAs were not significantly different than baseline levels among participants who discontinued FA supplementation. CONCLUSIONS The results of this study confirm that FA supplementation rapidly and significantly increases methylation of InAs to DMAs. Further research is needed to understand the strong cross-sectional associations between urinary creatinine and As methylation in previous studies. This trial was registered at https://clinicaltrials.gov as NCT01050556.
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Piezoresistivity of InAsP Nanowires: Role of Crystal Phases and Phosphorus Atoms in Strain-Induced Channel Conductances.
Kim, I, Kim, HS, Ryu, H
Molecules (Basel, Switzerland). 2019;(18)
Abstract
Strong piezoresistivity of InAsP nanowires is rationalized with atomistic simulations coupled to Density Functional Theory. With a focal interest in the case of the As(75%)-P(25%) alloy, the role of crystal phases and phosphorus atoms in strain-driven carrier conductance is discussed with a direct comparison to nanowires of a single crystal phase and a binary (InAs) alloy. Our analysis of electronic structures presents solid evidences that the strong electron conductance and its sensitivity to external tensile stress are due to the phosphorous atoms in a Wurtzite phase, and the effect of a Zincblende phase is not remarkable. With several solid connections to recent experimental studies, this work can serve as a sound framework for understanding of the unique piezoresistive characteristics of InAsP nanowires.
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[Research progress in mineral Chinese medicine realgar].
Song, LL, Han, DY, Lin, RC, Huang, JM, Guan, J
Zhongguo Zhong yao za zhi = Zhongguo zhongyao zazhi = China journal of Chinese materia medica. 2019;(3):433-440
Abstract
Realgar is a mineral traditional medicine with definite efficacy. The function of realgar is detoxicating, insecticiding, eliminating dampness and phlegm, etc. It is widely applied in clinical practice by compatibility medicines. However, the safety and scientificalness of clinical application are questioned because of the toxic effect caused by arsenic compounds. At present, there are still many problems in the research of realgar, which are mainly manifested in three areas: the expression of main components and effective substances are inconsistent; the anti-tumor mechanism is difficult to explain at the molecular level; the mechanism of compatibility is not clear. As a result, realgar and realgar-containing Chinese patent medicines are frequently prohibited from entering the international market, and the reputation of traditional Chinese medicine is also damaged. This paper would analyze the research status of realgar at home and abroad as well as its problems from its main components, effective substances, anti-tumor mechanism and compatibility mechanism. In view of these difficulties, quantum chemical calculation method is proposed to solve them, so as to make up for the shortcomings and limitations of experimental technology and experimental conditions, reduce the cost of realgar research and improve research efficiency. Moreover, it provides inspiration for research of other mineral medicine.
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Raman spectra of thiolated arsenicals with biological importance.
Yang, M, Sun, Y, Zhang, X, McCord, B, McGoron, AJ, Mebel, A, Cai, Y
Talanta. 2018;:520-530
Abstract
Surface enhanced Raman scattering (SERS) has great potential as an alternative tool for arsenic speciation in biological matrices. SERS measurements have advantages over other techniques due to its ability to maintain the integrity of arsenic species and its minimal requirements for sample preparation. Up to now, very few Raman spectra of arsenic compounds have been reported. This is particularly true for thiolated arsenicals, which have recently been found to be widely present in humans. The lack of data for Raman spectra in arsenic speciation hampers the development of new tools using SERS. Herein, we report the results of a study combining the analysis of experimental Raman spectra with that obtained from density functional calculations for some important arsenic metabolites. The results were obtained with a hybrid functional B3LYP approach using different basis sets to calculate Raman spectra of the selected arsenicals. By comparing experimental and calculated spectra of dimethylarsinic acid (DMAV), the basis set 6-311++G** was found to provide computational efficiency and precision in vibrational frequency prediction. The Raman frequencies for the rest of organoarsenicals were studied using this basis set, including monomethylarsonous acid (MMAIII), dimethylarsinous acid (DMAIII), dimethylmonothioarinic acid (DMMTAV), dimethyldithioarsinic acid (DMDTAV), S-(Dimethylarsenic) cysteine (DMAIII(Cys)) and dimethylarsinous glutathione (DMAIIIGS). The results were compared with fingerprint Raman frequencies from As─O, As─C, and As─S obtained under different chemical environments. These fingerprint vibrational frequencies should prove useful in future measurements of different species of arsenic using SERS.
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Urinary Arsenic in Human Samples from Areas Characterized by Natural or Anthropogenic Pollution in Italy.
Minichilli, F, Bianchi, F, Ronchi, AM, Gorini, F, Bustaffa, E
International journal of environmental research and public health. 2018;(2)
Abstract
Arsenic is ubiquitous and has a potentially adverse impact on human health. We compared the distribution of concentrations of urinary inorganic arsenic plus methylated forms (uc(iAs+MMA+DMA)) in four Italian areas with other international studies, and we assessed the relationship between uc(iAs+MMA+DMA) and various exposure factors. We conducted a human biomonitoring study on 271 subjects (132 men) aged 20-44, randomly sampled and stratified by area, gender, and age. Data on environmental and occupational exposure and dietary habits were collected through a questionnaire. Arsenic was speciated using chromatographic separation and inductively coupled mass spectrometry. Associations between uc(iAs+MMA+DMA) and exposure factors were evaluated using the geometric mean ratio (GMR) with a 90% confidence interval by stepwise multiple regression analysis. The 95th percentile value of uc(iAs+MMA+DMA) for the whole sample (86.28 µg/L) was higher than other national studies worldwide. A statistical significant correlation was found between uc(iAs+MMA+DMA) and occupational exposure (GMR: 2.68 [1.79-4.00]), GSTT gene (GMR: 0.68 [0.52-0.80]), consumption of tap water (GMR: 1.35 [1.02-1.77]), seafood (GMR: 1.44 [1.11-1.88]), whole milk (GMR: 1.34 [1.04-1.73]), and fruit/vegetables (GMR: 1.37 [1.03-1.82]). This study demonstrated the utility of uc(iAs+MMA+DMA) as a biomarker to assess environmental exposure. In a public health context, this information could be used to support remedial action, to prevent individuals from being further exposed to environmental arsenic sources.
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Double-Sided Personality: Effects of Arsenic Trioxide on Inflammation.
Zhang, J, Zhang, Y, Wang, W, Li, C, Zhang, Z
Inflammation. 2018;(4):1128-1134
Abstract
In 1992, arsenic trioxide (As2O3, ATO) was demonstrated to be an effective therapeutic agent against acute promyelocytic leukemia (APL), rekindling attention to ATO applications in U.S. Food and Drug Administration clinical trials for the treatment of cancers, such as leukemia, lymphomas, and solid tumors. ATO is a potent chemotherapeutic drug that can also be used to treat other diseases, such as autoimmune diseases, because it affects multiple pathways including apoptosis induction, differentiation stimulation, and proliferation inhibition. As inflammation is a critical component of disease progression, ATO is a feasible treatment option based on its ability to protect against inflammation. However, ATO is also a well-known carcinogen because of its pro-inflammatory effect. This review will focus on the double-sided effects of ATO on inflammation as well as the relevant mechanisms underlying these effects, aiming to provide a rational understanding of how ATO effects the immune system. We especially aim to provide a comprehensive overview of our current knowledge of how ATO influences inflammation.
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Characteristics of fibrinolytic disorders in acute promyelocytic leukemia.
Wang, P, Zhang, Y, Yang, H, Hou, W, Jin, B, Hou, J, Li, H, Zhao, H, Zhou, J
Hematology (Amsterdam, Netherlands). 2018;(10):756-764
Abstract
OBJECTIVES Catastrophic hemorrhage remains the main cause of acute promyelocytic leukemia (APL) treatment failure. This study was aimed to study the pathogenesis of coagulopathy in patients with APL. METHODS Multiple procoagulant and profibrinolytic parameters in plasma and peripheral leukocytes from 24 patients with newly diagnosed APL accompanied by coagulopathy before and after arsenic trioxide (ATO) treatment were evaluated. RESULTS Prior to the treatment, the patients had elevated D-dimer and decreased fibrinogen levels. Plasma urokinase-type plasminogen activator receptor (uPAR) and plasmin-ɑ2 antiplasmin complexes (PAP) levels, plasmin (Pn) activity, and cell surface levels of urokinase-type plasminogen activator (uPA) and tissue-type plasminogen activator (tPA) were significantly higher; plasma plasminogen activator inhibitor-1 (PAI-1) levels and plasminogen (Pg) activity were significantly decreased; plasma plasminogen activator (PA) activity, uPA and tPA levels; and cell surface levels of uPAR and annexin II were not significantly different from levels in the control group. During ATO treatment, both patients' plasma PA activity and uPAR on leukocytes gradually increased, annexin II on leukocytes increased initially and decreased afterwards, and tPA and uPA on leukocytes remained consistently higher in the patients than in the controls. Other parameters gradually tended toward normal values. CONCLUSIONS In APL, activated coagulation system activated fibrinolytic system, and increased uPAR levels could contribute to the hyperfibrinolysis. Annexin II might not be involved in the coagulopathy.
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Regulation of ABCG2 by nuclear factor kappa B affects the sensitivity of human lung adenocarcinoma A549 cells to arsenic trioxide.
Jiang, X, Chen, C, Gu, S, Zhang, Z
Environmental toxicology and pharmacology. 2018;:141-150
Abstract
Arsenic trioxide (As2O3) is successfully used as an anticancer agent against acute promyelocytic leukemia and some solid tumors. However, the application of As2O3 is largely limited by its drug resistance in the treatment of non-small cell lung carcinoma (NSCLC). Therefore, it is an urgent task to enhance the sensitivity of lung cancer cells to As2O3. In this study, using human lung adenocarcinoma A549 cells as a cell culture model, we demonstrated that an adenosine triphosphate binding cassette (ABC) transporter, ABCG2, was significantly increased by As2O3 treatment, while other ABC transporters, ABCB1 and ABCC1 showed no remarkable change in the response to As2O3. After inhibition of ABCG2 by its specific inhibitor, the drug sensitivity of As2O3 to A549 cells was significantly enhanced, manifested by decreased cell viability and colony formation as well as the increased ROS production and cell apoptosis. To further understand the molecular mechanism underlying the elevation of ABCG2 expression in As2O3-treated cells, we detected the activation state of nuclear factor kappa B (NF-κB) pathway and its relationship with ABCG2 expression. Our results revealed that the increased expression of ABCG2 was regulated by NF-κB, and thus affecting the cell death of As2O3-treated A549 cells. These findings indicate that inhibition of NF-κB/ABCG2 pathway by specific inhibitors may be a new strategy for the improvement of As2O3 sensitivity in NSCLC treatment.
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Arsenic speciation in the phloem exudates of rice and its role in arsenic accumulation in rice grains.
Ye, W, Zhang, J, Fan, T, Lu, H, Chen, H, Li, X, Hua, R
Ecotoxicology and environmental safety. 2017;:87-91
Abstract
Arsenic (As) speciation in the phloem sap of rice plants and its role in As accumulation in rice grains remain largely uncharacterized. In the present study, we tested As chemical species in the phloem exudates of rice treated with arsenate [As(V)], arsenite [As(III)], monomethylarsonic acid [MMA(V)], or dimethylarsinic acid [DMA(V)]. As(V) was the main species (58%) in the phloem exudates of As(V)-exposed rice, whereas As(III) predominated (69%) in As(III)-exposed rice. A large proportion of As(V) (41-45%) was observed in the phloem exudates when rice was treated with methylated As species. High concentrations of phytochelatins were detected in the phloem exudates when the As(V) treatment level was increased. The role of phloem transport was analyzed by applying a ±stem-girdling treatment to the rice plants, limiting phloem transport to the grain in rice pulsed with As(III), As(V), MMA(V), or DMA(V). The findings of the present study indicate that organic As is more mobile than inorganic As during phloem transport. Phloem transport accounted for 54% of As(III), 56% of As(V), 100% of MMA(V), and 89% of DMA(V) transport to the grain. The total As concentration and As(III) percentage in rice phloem and grain were significantly affected by increasing the phosphate concentration in the medium.
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[miR-155/BACH1 Signaling Pathway in Human Lung Adenocarcinoma Cell Death Induced by Arsenic Trioxide].
Gu, SY, Chen, HY, Dai, HM, Li, XY, Zhang, ZZ
Sichuan da xue xue bao. Yi xue ban = Journal of Sichuan University. Medical science edition. 2017;(6):828-833
Abstract
OBJECTIVE To explore the changes of micro RNA 155 (miR-155),BTB and CNC homologous protein 1 (BACH1),quinone oxidoreductase 1 (NQO1) and heme-oxygenase-1 (HO-1) in the process of arsenic trioxide-induced cell death,and to clarify the relationship between miR-155 and BACH1,providing experimental basis for the sensitivity of arsenic trioxide (ATO) treatment. METHODS Human lung adenocarcinoma cell line A549 cells were treated with different concentrations of ATO. MTT assay and total antioxidant capacity detection kit were used to determine cell viability and total antioxidant capacity,respectively. BACH1,NQO1 and HO-1 protein expression were probed by Western blot and real-time fluorescence quantitative (qRT-PCR) was utilized to test the miR-155 level. A549 cells were transfected with miR-155 mimic and its negative control,then the expression level of miR-155 was detected by qRT-PCR,and these cells were treated with 20 μmol/L for 24 h followed by MTT and Western blot detection. RESULTS 10 μmol/L ATO significantly reduced the cell viability in A549 cells. 10 μmol/L and 20 μmol/L ATO treatment activated BACH1 expression and inhibited miR-155,NQO1 and HO-1 expression,leading to decreased total antioxidant capacity. Importantly,the cell death induced by 20 μmol/L ATO was significantly decreased in miR-155 mimic transfection cells in comparison with non-transfected cells and miR-155 mimic negative control transfected cells. Moreover,high expression of miR-155 reduced BACH1 activation and increased NQO1 and HO-1 expression in cells treated with 20 μmol/L ATO ( P<0.05). CONCLUSION Restraining total antioxidant capacity contributes to ATO induced cell death,the underlying mechanisms may be that ATO can activate BACH1 expression through inhibition of the miR-155 level,leading to subsequent inhibition of NQO1 and HO-1 expression. Taken together,these data suggest that miR-155 and BACH1 could be used as sensitivity targets for ATO treatment in lung cancer.