BioMetals (v.31, #4)
A review of cardiovascular toxicity of TiO2, ZnO and Ag nanoparticles (NPs) by Yi Cao; Yu Gong; Wenzhen Liao; Yunfeng Luo; Chaohua Wu; Maolin Wang; Qianyu Yang (457-476).
To ensure the safe use of nanoparticles (NPs) in modern society, it is necessary and urgent to assess the potential toxicity of NPs. Cardiovascular system is required for the systemic distribution of NPs entering circulation. Therefore, the adverse cardiovascular effects of NPs have gained extensive research interests. Metal based NPs, such as TiO2, ZnO and Ag NPs, are among the most popular NPs found in commercially available products. They may also have potential applications in biomedicine, which could increase their contact with cardiovascular systems. This review aimed at providing an overview about the adverse cardiovascular effects of TiO2, ZnO and Ag NPs. We discussed about the bio-distribution of NPs following different exposure routes. We also discussed about the cardiovascular toxicity of TiO2, ZnO and Ag NPs as assessed by in vivo and in vitro models. The possible mechanisms and contribution of physicochemical properties of metal based NPs were also discussed.
Keywords: Nanoparticles (NPs); Bio-distribution; Cardiovascular toxicity; Oxidative stress; Inflammation
Hexavalent chromium, a lung carcinogen, confers resistance to thermal stress and interferes with heat shock protein expression in human bronchial epithelial cells by Patrícia L. Abreu; Teresa Cunha-Oliveira; Leonardo M. R. Ferreira; Ana M. Urbano (477-487).
Exposure to hexavalent chromium [Cr(VI)], a lung carcinogen, triggers several types of cellular stresses, namely oxidative, genotoxic and proteotoxic stresses. Given the evolutionary character of carcinogenesis, it is tempting to speculate that cells that survive the stresses produced by this carcinogen become more resistant to subsequent stresses, namely those encountered during neoplastic transformation. To test this hypothesis, we determined whether pre-incubation with Cr(VI) increased the resistance of human bronchial epithelial cells (BEAS-2B cells) to the antiproliferative action of acute thermal shock, used here as a model for stress. In line with the proposed hypothesis, it was observed that, at mildly cytotoxic concentrations, Cr(VI) attenuated the antiproliferative effects of both cold and heat shock. Mechanistically, Cr(VI) interfered with the expression of two components of the stress response pathway: heat shock proteins Hsp72 and Hsp90α. Specifically, Cr(VI) significantly depleted the mRNA levels of the former and the protein levels of the latter. Significantly, these two proteins are members of heat shock protein (Hsp) families (Hsp70 and Hsp90, respectively) that have been implicated in carcinogenesis. Thus, our results confirm and extend previous studies showing the capacity of Cr(VI) to interfere with the expression of stress response components.
Keywords: Hexavalent chromium; Lung carcinogen; Thermal shock; Stress response; Heat shock proteins
Genome-wide and comparative analysis of bHLH38, bHLH39, bHLH100 and bHLH101 genes in Arabidopsis, tomato, rice, soybean and maize: insights into iron (Fe) homeostasis by Fırat Kurt; Ertugrul Filiz (489-504).
Iron (Fe) is an essential element for plant life. Its deficiency impedes growth and development and excessive iron can cause the toxic effect via the Fenton reaction. Thus, plants have developed various mechanisms to acquire, distribute and utilize Fe for the maintenance of their iron homeostasis at cellular and systemic levels. A basic helix-loop-helix (bHLH) transcription factor family plays essential roles in many regulatory and development processes in plants. In this study, we aimed to understand the roles of bHLH38, bHLH39, bHLH100 and bHLH101 genes for Fe homeostasis in Arabidopsis, tomato, rice, soybean and maize species by using bioinformatics approaches. The gene/protein sequence analyses of these genes demonstrated that all bHLH proteins comprised helix-loop-helix DNA binding domain (PF00010) with varied exon numbers between 2 and 13. The phylogenetic analysis did not reveal a clear distinction between monocot and dicot plants. A total of 61 cis-elements were found in promotor sequences, including biotic and abiotic stress responsiveness, hormone responsiveness, and tissue specific expressions. The some structural divergences were identified in predicted 3D structures of bHLH proteins with different channels numbers. The co-expression network analysis demonstrated that bHLH39 and bHLH101 played more important roles in Fe regulation in Arabidopsis. The digital expression analysis showed various expression profiles of bHLH genes which were identified in developmental stages, anatomical parts, and perturbations. Particularly, bHLH39 and bHLH101 genes were found to be more active genes in Fe homeostasis. As a result, our findings can contribute to understanding of bHLH38, bHLH39, bHLH100 and bHLH101 genes in Fe homeostasis in plants.
Keywords: Iron homeostasis; Bioinformatics; Co-expression network; bHLH
Copper complex derived from S-benzyldithiocarbazate and 3-acetylcoumarin induced apoptosis in breast cancer cell by Jhi Biau Foo; May Lee Low; Ji Hui Lim; Yan Zhi Lor; Rusyidah Zainol Abidin; Vilasini Eh Dam; Napsiah Abdul Rahman; Chaw Yee Beh; Lee Chin Chan; Chee Wun How; Yin Sim Tor; Latifah Saiful Yazan (505-515).
Copper complexes have been widely studied for the anti-tumour application as cancer cells are reported to take up greater amounts of copper than normal cells. Preliminary study revealed that the newly synthesised copper complex [Cu(SBCM)2] displayed marked anti-proliferative towards triple-negative MDA-MB-231 breast cancer cells. Therefore, Cu(SBCM)2 has great potential to be developed as an agent for the management of breast cancer. The present study was carried out to investigate the mode of cell death induced by Cu(SBCM)2 towards MDA-MB-231 breast cancer cells. The inhibitory and morphological changes of MDA-MB-231 cells treated with Cu(SBCM)2 was determined by using MTT assay and inverted light microscope, respectively. The safety profile of Cu(SBCM)2 was also evaluated towards human dermal fibroblast (HDF) normal cells. Confirmation of apoptosis and cell cycle arrest were determined by flow cytometry analysis. The expression of p53, Bax, Bcl-2 and MMP2 protein were detected with western blot analysis. Cu(SBCM)2 significantly inhibited the growth of MDA-MB-231 cells in a dose-dependent manner with GI50 18.7 ± 3.06 µM. Indeed, Cu(SBCM)2 was less toxic towards HDF normal cells with GI50 31.8 ± 4.0 µM. Morphological study revealed that Cu(SBCM)2-treated MDA-MB-231 cells experienced cellular shrinkage, membrane blebbing, chromatin condensation and formation of apoptotic bodies, suggesting that Cu(SBCM)2 induced apoptosis in the cells, which was confirmed by Annexin-V/PI flow cytometry analysis. It was also found that Cu(SBCM)2 induced G2/M phase cell cycle arrest towards MDA-MB-231 cells. The induction of apoptosis and cell cycle arrest in the present study is possibly due to the down-regulation of the mutant p53 and MMP2 protein. In conclusion, Cu(SBCM)2 can be developed as a targeted therapy for the treatment of triple-negative breast cancer.
Keywords: Copper(II) Schiff-base; Breast cancer; Apoptosis; Cell cycle arrest; p53
The cluster [Re6Se8I6]3− penetrates biological membranes: drug-like properties for CNS tumor treatment and diagnosis by Lisbell D. Estrada; Elizabeth Duran; Matias Cisterna; Cesar Echeverria; Zhiping Zheng; Vincenzo Borgna; Nicolas Arancibia-Miranda; Rodrigo Ramírez-Tagle (517-525).
Tumorigenic cell lines are more susceptible to [Re6Se8I6]3− cluster-induced death than normal cells, becoming a novel candidate for cancer treatment. Still, the feasibility of using this type of molecules in human patients remains unclear and further pharmacokinetics analysis is needed. Using coupled plasma optical emission spectroscopy, we determined the Re-cluster tissue content in injected mice, as a biodistribution measurement. Our results show that the Re-cluster successfully reaches different tissues, accumulating mainly in heart and liver. In order to dissect the mechanism underlying cluster biodistribution, we used three different experimental approaches. First, we evaluate the degree of lipophilicity by determining the octanol/water partition coefficient. The cluster mostly remained in the octanol fraction, with a coefficient of 1.86 ± 0.02, which indicates it could potentially cross cell membranes. Then, we measured the biological membrane penetration through a parallel artificial membrane permeability assays (PAMPA) assay. The Re-cluster crosses the artificial membrane, with a coefficient of 122 nm/s that is considered highly permeable. To evaluate a potential application of the Re-cluster in central nervous system (CNS) tumors, we analyzed the cluster’s brain penetration by exposing cultured blood–brain-barrier (BBB) cells to increasing concentrations of the cluster. The Re-cluster effectively penetrates the BBB, reaching nearly 30% of the brain side after 24 h. Thus, our results indicate that the Re-cluster penetrates biological membranes reaching different target organs—most probably due to its lipophilic properties—becoming a promising anti-cancer drug with high potential for CNS cancer’s diagnosis and treatment.
Keywords: Cluster; Blood–brain barrier (BBB); Brain; Tumors; Cancer
Six indicator genes for zinc (Zn) homeostasis in freshwater teleost yellow catfish Pelteobagrus fulvidraco: molecular characterization, mRNA tissue expression and transcriptional changes to Zn exposure by Guang-Hui Chen; Zhi Luo; Chuan-Chuan Wei; Dan-Dan Li; Ya-Xiong Pan (527-537).
Excessive Zn in the aquatic environment can be toxic and causes dysfunction in Zn homeostasis for fish, which ultimately influences the function of various biological processes. Zn homeostasis is controlled by Zn transporters. This study cloned and characterized the full-length cDNA sequences of six Zn transport-relevant genes (ZnT1, ZnT5, ZnT7, ZIP4, ZIP5 and MTF-1) from yellow catfish Pelteobagrus fulvidraco. The six genes share similar domains to their corresponding members of mammals. Their mRNA amounts were widely existent across eight tissues (intestine, liver, brain, heart, gill, muscle, spleen and mesenteric fat), but relatively predominant in the liver and intestine. On day 28, Zn exposure tended to increase transcript levels of ZnT1, ZnT5 and MTF-1, decrease hepatic ZIP5 expression, but did not significantly affect the expression of ZnT7 and ZIP4. On day 56, Zn exposure tended to increase transcript levels of ZnT1 and MTF-1, down-regulate hepatic mRNA amounts of ZIP4 and ZIP5; among three Zn treatments, ZnT5 expression in the 0.5 mg Zn/L group and ZnT7 expression in the 0.25 mg Zn/L group were the highest. The mRNA abundances of these genes showed Zn concentration- and exposure time-dependent manners. For the first time, we characterized the full-length cDNA sequences of six Zn transport-relevant genes in fish, explored their tissue expression profiles and transcriptional responses to Zn exposure. Our study built good basis for further investigating their physiological functions of these genes and provided new insights into the regulatory mechanisms of Zn homeostasis in fish.
Keywords: Pelteobagrus fulvidraco ; Zn exposure; Zn transporter; Zn homeostasis
Binding of Cd(II), Pb(II), and Zn(II) to a type 1 metallothionein from maize (Zea mays) by Lian Duan; Jing-Jing Kong; Tong-Qing Wang; Yue Sun (539-550).
Metallothioneins (MTs) are a family of ubiquitous, low-molecular-mass, cysteine-rich proteins that play a significant role in maintaining intracellular metal homeostasis, eliminating metal toxification, and protecting cells against oxidative damages. Research activity on plant MTs, although known for 30 years, has only moderately increased in the past few years. In this study, a type 1 MT from maize (Zea mays) (ZmMT1) was successfully expressed in Escherichia coli strain BL21 (DE3). The UV absorption spectra recorded after the reconstitution of apo-ZmMT1 with different metals demonstrated that ZmMT1 can coordinate up to six Zn(II) ions, six Cd(II) ions, and even higher amounts of Pb(II). In addition, the general metal ion coordination abilities of ZmMT1 characterized by pH-dependent zinc-, lead- and cadmium-binding stability and by the competitive reaction with 5,5′-dithiobis-(2-nitrobenzoic acid) (DTNB) were evaluated. Results showed that the affinity of metal ions for the recombinant form of ZmMT1 can be arranged as follows: Cd(II) > Pb(II) > Zn(II). The observation revealed that chelating agents, such as ethylene diamine tetraacetic acid (EDTA) and ATP, accelerate the oxidation of ZmMT1 in the following order: EDTA ≫ l-histidine > ATP ≈ citrate. Meanwhile, commonly used buffers increase the reactivity of ZmMT1 with DTNB in the following order: PBS > Tris–HCl > HEPES.
Keywords: Metallothionein; Metal ions binding; pH stability; Oxidation rates
Effects of iron on the aggregation propensity of the N-terminal fibrillogenic polypeptide of human apolipoprotein A-I by Rita Del Giudice; Alessandra Pesce; Flora Cozzolino; Maria Monti; Annalisa Relini; Renata Piccoli; Angela Arciello; Daria Maria Monti (551-559).
Specific mutations in APOA1 gene lead to systemic, hereditary amyloidoses. In ApoA-I related amyloidosis involving the heart, amyloid deposits are mainly constituted by the 93-residue N-terminal region of the protein, here indicated as [1-93]ApoA-I. Oxidative stress is known to be an enhancing factor for protein aggregation. In healthy conditions, humans are able to counteract the formation and the effects of oxidative molecules. However, aging and atmospheric pollution increase the concentration of oxidative agents, such as metal ions. As the main effect of iron deregulation is proposed to be an increase in oxidative stress, we analysed the effects of iron on [1-93]ApoA-I aggregation. By using different biochemical approaches, we demonstrated that Fe(II) is able to reduce the formation of [1-93]ApoA-I fibrillar species, probably by stabilizing its monomeric form, whereas Fe(III) shows a positive effect on polypeptide fibrillogenesis. We hypothesize that, in healthy conditions, Fe(III) is reduced by the organism to Fe(II), thus inhibiting amyloid formation, whereas during ageing such protective mechanisms decline, thus exposing the organism to higher oxidative stress levels, which are also related to an increase in Fe(III). This alteration could contribute to the pathogenesis of amyloidosis.
Keywords: Protein aggregation; Conformational analysis; ApoA-I; Amyloidosis; Iron
Iron overload prevents oxidative damage to rat brain after chlorpromazine administration by Natacha E. Piloni; Andres A. Caro; Susana Puntarulo (561-570).
The hypothesis tested is that Fe administration leads to a response in rat brain modulating the effects of later oxidative challenges such as chlorpromazine (CPZ) administration. Either a single dose (acute Fe overload) or 6 doses every second day (sub-chronic Fe overload) of 500 or 50 mg Fe-dextran/kg, respectively, were injected intraperitoneally (ip) to rats. A single dose of 10 mg CPZ/kg was injected ip 8 h after Fe treatment. DNA integrity was evaluated by quantitative PCR, lipid radical (LR·) generation rate by electron paramagnetic resonance (EPR), and catalase (CAT) activity by UV spectrophotometry in isolated brains. The maximum increase in total Fe brain was detected after 6 or 2 h in the acute and sub-chronic Fe overload model, respectively. Mitochondrial and nuclear DNA integrity decreased after acute Fe overload at the time of maximal Fe content; the decrease in DNA integrity was lower after sub-chronic than after acute Fe overload. CPZ administration increased LR· generation rate in control rat brain after 1 and 2 h; however, CPZ administration after acute or sub-chronic Fe overload did not affect LR· generation rate. CPZ treatment did not affect CAT activity after 1–4 h neither in control rats nor in acute Fe-overloaded rats. However, CPZ administration to rats treated sub-chronically with Fe showed increased brain CAT activity after 2 or 4 h, as compared to control values. Fe supplementation prevented brain damage in both acute and sub-chronic models of Fe overload by selectively activating antioxidant pathways.
Keywords: Brain; Oxidative stress; Fe; Chlorpromazine; Antioxidant; Electron paramagnetic resonance
5-Nitroimidazole-derived Schiff bases and their copper(II) complexes exhibit potent antimicrobial activity against pathogenic anaerobic bacteria by Alexandre A. Oliveira; Ana P. A. Oliveira; Lucas L. Franco; Micael O. Ferencs; João F. G. Ferreira; Sofia M. P. S. Bachi; Nivaldo L. Speziali; Luiz M. Farias; Paula P. Magalhães; Heloisa Beraldo (571-584).
In the present work a family of novel secnidazole-derived Schiff base compounds and their copper(II) complexes were synthesized. The antimicrobial activities of the compounds were evaluated against clinically important anaerobic bacterial strains. The compounds exhibited in vitro antibacterial activity against Bacteroides fragilis, Bacteroides thetaiotaomicron, Bacteroides vulgatus, Bacteroides ovatus, Parabacteroides distasonis and Fusubacterium nucleatum pathogenic anaerobic bacteria. Upon coordination to copper(II) the antibacterial activity significantly increased in several cases. Some derivatives were even more active than the antimicrobial drugs secnidazole and metronidazole. Therefore, the compounds under study are suitable for in vivo evaluation and the microorganisms should be classified as susceptible to them. Electrochemical studies on the reduction of the nitro group revealed that the compounds show comparable reduction potentials, which are in the same range of the bio-reducible drugs secnidazole and benznidazole. The nitro group reduction potential is more favorable for the copper(II) complexes than for the starting ligands. Hence, the antimicrobial activities of the compounds under study might in part be related to intracellular bio-reduction activation. Considering the increasing resistance rates of anaerobic bacteria against a wide range of antimicrobial drugs, the present work constitutes an important contribution to the development of new antibacterial drug candidates.
Keywords: 5-Nitroimidazole; Copper(II) complexes; Schiff bases; Anaerobic bacteria; Antimicrobial activity; Bio-reduction
CatroxMP-II: a heme-modulated fibrinogenolytic metalloproteinase isolated from Crotalus atrox venom by Montamas Suntravat; Paul R. Langlais; Elda E. Sánchez; Vance G. Nielsen (585-593).
It has been recently demonstrated that the hemotoxic venom activity of several species of snakes can be inhibited by carbon monoxide (CO) or a metheme forming agent. These and other data suggest that the biometal, heme, may be attached to venom enzymes and may be modulated by CO. A novel fibrinogenolytic metalloproteinase, named CatroxMP-II, was isolated and purified from the venom of a Crotalus atrox viper, and subjected to proteolysis and mass spectroscopy. An ion similar to the predicted singly charged m/z of heme at 617.18 was identified. Lastly, CORM-2 (tricarbonyldichlororuthenium (II) dimer, a CO releasing molecule) inhibited the fibrinogenolytic effects of CatroxMP-II on coagulation kinetics in human plasma. In conclusion, we present the first example of a snake venom metalloproteinase that is heme-bound and CO-inhibited.
Keywords: Snake venom metalloproteinase; Heme; Mass spectrometry; Carbon monoxide; Thrombelastography
Expression of genes associated with inflammation and iron metabolism in 3T3-L1 cells induced with macrophages-conditioned medium, glucose and iron by L. Briones; M. Andrews; F. Pizarro; M. Arredondo-Olguín (595-604).
Obesity is characterized by a chronic inflammatory process, with an increased volume of total adipose tissue, especially visceral, which secretes pro-inflammatory cytokines such as TNF-α and IL-6. Hepcidin (Hpc), a main iron metabolism regulator, is synthetized by an IL-6 stimuli, among others, in liver and adipose tissue, favoring an association between the inflammatory process and iron metabolism. Still there are questions remain regarding the interaction of these factors. Our aim was to study the effect of a macrophage-conditioned medium (MCM) on adipocyte cells challenged with glucose and/or iron. We studied the mRNA relative abundance of genes related to inflammation in differentiated 3T3-L1 cells challenged with Fe (40 µM), glucose (20 mM) or Fe/glucose (40 µM/20 mM) with or without MCM for 24 h. We also measured the intracellular iron levels under these conditions. Our results showed that when adipocytes were challenged with MCM, glucose and/or Fe, the intracellular iron and mRNA levels of pro-inflammatory cytokines increased. These responses were higher when all the stimuli were combined with MCM from macrophages. Thus, we showed that combined high glucose/high Fe alone or with MCM may contribute to an increase on intracellular iron and inflammatory response in 3T3-L1 differentiated cells, by increased mRNA levels of IL-6, TNF-α, MCP-1, Hpc and reducing adiponectin levels, enhancing the inflammatory processes.
Keywords: Inflammation; Adipocytes; Iron; Macrophages; Conditioned medium
Gadopentatic acid affects in vitro proliferation and doxorubicin response in human breast adenocarcinoma cells by Abdel Rahman Abdel Fattah; Sarah Mishriki; Tobias Kammann; Rakesh P. Sahu; Fei Geng; Ishwar K. Puri (605-616).
Contrasting agents (CAs) that are administered to patients during magnetic resonance imaging to facilitate tumor identification are generally considered harmless. However, gadolinium (Gd) based contrast agents can be retained in the body, inflicting specific cell line cytotoxicity. We investigate the effect of Gadopentatic acid (Gd-DTPA) on human breast adenocarcinoma MCF-7 cells. These cells exhibit a toggle switch response: exposure to 0.1 and 1 mM concentrations of Gd-DTPA enhances proliferation, which is hindered at a higher 10 mM concentration. Proliferation is enhanced when cells transition to 3D morphologies in post confluent conditions. The proliferation dependence on the concentration of CA is absent for Hs 578T and MDA-MB-231 triple negative cell lines. MCF-7 cells reveal a double toggle switch related to the expression of VEGF, which goes through high–low–high downregulation when cells are exposed to 0.1, 1, and 10 mM Gd-DTPA, respectively. Finally, doxorubicin drug response is assessed, which also reveals a double toggle switch behavior, where drug cytotoxicity exhibits a nonlinear dependence on the CA concentration. A toggle switch in cell characteristics that are exposed to 1 mM of Gd-DTPA amplifies the importance of this threshold, affecting several cell behaviors if surpassed. This work emphasizes the important effects that CAs can have on cells, specifically Gd-DTPA on MCF-7 cells, and the implications for cell growth and drug response during clinical and synthetic biology procedures.
Keywords: Magnetic resonance imagining; Contrasting agents; Gadopentatic acid; Breast cancer; Paramagnetism
Metallothionein is elevated in liver and duodenum of Atp7b(−/−) mice by Chengcheng Christine Zhang; Martin Volkmann; Sabine Tuma; Wolfgang Stremmel; Uta Merle (617-625).
Different mutations in the copper transporter gene Atp7b are identified as the primary cause of Wilson’s disease. These changes result in high copper concentrations especially in the liver and brain, and consequently lead to a dysfunction of these organs. The Atp7(−/−) mouse is an established animal model for Wilson’s disease and characterized by an abnormal copper accumulation, a low serum oxidase activity and an increased copper excretion in urine. Metallothionein (MT) proteins are low molecular weight metal-binding proteins and essential for the zinc homeostasis but also play a role for the regulation of other metals, e.g. copper. However the molecular mechanisms of MT in regard to Atp7b remain still elusive. In this study we investigate the expression of MT in the liver and duodenum of Atp7b(−/−) mice and wildtype mice. Hepatic and duodenal expression of MT was measured by real-time reverse transcription-polymerase chain reaction and post-translational expression was analyzed by immunoblot and immunofluorescence. Expression of MT in liver und duodenum was significantly higher in Atp7b(−/−) mice than in controls. Hepatic and duodenal copper, iron and zinc content were also studied. Compared to control hepatic copper and iron content was significantly higher while hepatic zinc content was significantly lower in Atp7b(−/−) mice. In the duodenum copper and zinc content of Atp7b(−/−) mice was significantly lower than in controls. Duodenal iron content was also lower in Atp7b(−/−) mice, but did not reach statistical significance. The results of our study suggest that metallothionein is elevated in the liver and duodenum of Atp7b(−/−) mice.
Keywords: Wilson’s disease; Atp7b; Metallothionein; Copper; Liver; Duodenum
The potential role of spherocrystals in the detoxification of essential trace metals following exposure to Cu and Zn in the fighting conch Strombus (Lobatus) pugilis by Jean-Marie Volland; Paco Bustamante; Dalila Aldana Aranda; Olivier Gros (627-637).
Crypt cells—one of the three cell types composing Strombidae digestive tubules—are characterized by the presence of numerous metal-containing phosphate granules termed spherocrystals. We explored the bioaccumulation and detoxification of metals in Strombidae by exposing wild fighting conch Strombus pugilis for 9 days to waterborne CuSO4 and ZnSO4. The total amount of Cu and Zn was determined in the digestive gland and in the rest of the body by Inductively Coupled Plasma (ICP) analyses. The digestive gland spherocrystal metal content was investigated based on the semi-quantitative energy dispersive X-ray (EDX) elemental analysis. ICP analyses of unexposed individuals revealed that 87.0 ± 5.9% of the Zn is contained in the digestive gland, where its concentration is 36 times higher than in the rest of the body. Regarding Cu, 25.8 ± 16.4% of the metal was located in the digestive gland of the control individuals, increasing to 61.5 ± 16.4% in exposed individuals. Both Cu and Zn concentrations in the digestive gland increased after exposures, pointing to a potential role of this organ in the detoxification of these metals. EDX analysis of spherocrystals revealed the presence of Ca, Cl, Fe, K, Mg, P, and Zn in unexposed individuals. No difference was found in the relative proportion of Zn in spherocrystals of exposed versus control individuals. Contrastingly, copper was never detected in the spherocrystals from controls and Zn-exposed individuals, but the relative proportion of Cu in spherocrystals of Cu-exposed individuals varied from 0.3 to 5.7%. Our results show the direct role of spherocrystals in Cu detoxification.
Keywords: Exposure; Mollusca; Phosphate granule; Trace metal; Ultrastructure
Bioinformatic analysis of the metal response element and zinc-dependent gene regulation via the metal response element-binding transcription factor 1 in Caco-2 cells by Michael Francis; Arthur Grider (639-646).
The purpose of this study was to determine the correlation between the position or number of metal regulatory elements (MREs) near gene transcriptional or translational start sites, and the strength of metal response element-binding transcription factor 1 (MTF-1) regulation. A secondary analysis was performed in silico on published results measuring the effects of Zn and MTF-1 on transcriptional regulation of genes (n = 120) in the Caco-2 cell line. MRE sequence variations throughout the human genome were sorted using a position weight matrix. Three null hypotheses (H0) were tested: (1) there is no correlation between the number of MREs and MTF-1 transcriptional strength, (2) there is no correlation between the distance of the MRE upstream from the transcriptional start site (TSS) and MTF-1 transcriptional strength, and (3) there is no correlation between the distance of the MRE downstream from the translational start site (TrSS) and MTF-1 transcriptional strength. Spearman correlation was used to test for significance (p < 0.05). From our results we rejected the first H0; we observed a significant correlation between the total number of MRE sequences − 7Kbp upstream from the TSS, within the 5′ untranslated region, and + 1Kbp downstream from the TrSS, versus the strength of MTF-1 regulation (r = 0.202; p = 0.027). The second and third H0 were accepted. These results expand our understanding of the role of the MRE in Zn-dependent gene regulation. The data indicate that Zn influences the transcriptional control of gene expression beyond maintaining intracellular Zn homeostasis.
Keywords: MTF-1; MRE; Zinc; Nutrigenomics; Transcription factor
Vanadium quercetin complex attenuates mammary cancer by regulating the P53, Akt/mTOR pathway and downregulates cellular proliferation correlated with increased apoptotic events by Souvik Roy; Sritama Banerjee; Tania Chakraborty (647-671).
Flavonoid metal ion complexes have been deliberated in recent years and are considered as a new class of medicinal agents with enhanced therapeutic activity and low toxicity. Our study deals with chemotherapeutic effects of vanadium, when coordinated with the flavonoid quercetin on a defined model of chemically induced rat mammary carcinogenesis in vivo and on human breast cancer cell line MCF-7 in vitro. The characterization of the complex was achieved through UV–Visible, IR, and Mass spectra and antioxidant activity was assessed by DPPH, FRAP and ABTS methods. In vitro studies established that the complex upregulated the expressions of p53, Caspase 3 and 9, whereas down regulating Akt, mTOR and VEGF expressions and also induced apoptosis and DNA fragmentation in a dose dependent manner. Acute and Sub-acute toxicity was performed to determine safe doses. 7,12-Dimethylbenz(α)anthracene (0.5 mg/100 g body weight) was used for induction of breast cancer in female Sprague–Dawley rats via single tail vein injection. The histopathological analysis after 24 weeks of carcinogenesis study depicted substantial repair of hyperplastic lesions. TUNEL assay showed an increase in apoptotic index (0.14 ± 0.03; 0.15 ± 0.01) in vanadium–quercetin treated groups as compared to the carcinogen control (0.02 ± 0.01) along with upregulation of Bcl-2 and downregulation of Bax and p53. Immunohistochemical analysis also exhibited decrease in cell proliferation in the vanadium–quercetin treated groups (11.3 ± 0.12; 11.8 ± 0.10). Thus, results from both in vivo and in vitro studies revealed that vanadium–quercetin complex could be a potential candidate for development of approved drug for breast cancer in the near future.
Keywords: Mammary carcinogenesis; Sprague–Dawley rats; 7,12-Dimethylbenz(α)anthracene; Immunohistochemistry; TUNEL assay; MCF-7
Correlation between Na/K ratio and electron densities in blood samples of breast cancer patients by Ömer Topdağı; Ozan Toker; Sezgin Bakırdere; Ertuğrul Osman Bursalıoğlu; Ersoy Öz; Önder Eyecioğlu; Mustafa Demir; Orhan İçelli (673-678).
The main purpose of this study was to investigate the relationship between the electron densities and Na/K ratio which has important role in breast cancer disease. Determinations of sodium and potassium concentrations in blood samples performed with inductive coupled plasma-atomic emission spectrometry. Electron density values of blood samples were determined via ZXCOM. Statistical analyses were performed for electron densities and Na/K ratio including Kolmogorov–Smirnov normality tests, Spearman’s rank correlation test and Mann–Whitney U test. It was found that the electron densities significantly differ between control and breast cancer groups. In addition, statistically significant positive correlation was found between the electron density and Na/K ratios in breast cancer group.
Keywords: Blood samples; Breast cancer; Na/K ratio; Electron density; ICP-AES
Correction to: Metallic ion content and damage to the DNA in oral mucosa cells of children with fixed orthodontic appliances by Esther Fernández-Miñano; Clara Ortiz; Ascensión Vicente; José L. Calvo Guirado; Antonio J. Ortiz (679-679).
Due to an unfortunate turn of events, the surname of the fourth author appeared incorrectly in the original publication and should have read Calvo Guirado.