In-vitro cytotoxic and genotoxic effects of arsenic trioxide on human leukemia (HL-60) cells using the MTT and alkaline single cell gel electrophoresis (Comet) assays

Toxic and essential metals: metabolic interactions with the gut microbiota and health implications

Human exposure to heavy metals, which encompasses both essential and toxic varieties, is widespread. The intestine functions as a critical organ for absorption and metabolism of heavy metals. Gut microbiota plays a crucial role in heavy metal absorption, metabolism, and related processes. Toxic heavy metals (THMs), such as arsenic (As), mercury (Hg), lead (Pb), and cadmium (Cd), can cause damage to multiple organs even at low levels of exposure, and it is crucial to emphasize their potential high toxicity. Nevertheless, certain essential trace elements, including iron (Fe), copper (Cu), and manganese (Mn), play vital roles in the biochemical and physiological functions of organisms at low concentrations but can exert toxic effects on the gut microbiota at higher levels. Some potentially essential micronutrients, such as chromium (Cr), silicon (Si), and nickel (Ni), which were considered to be intermediate in terms of their essentiality and toxicity, had different effects on the gut microbiota and their metabolites. Bidirectional relationships between heavy metals and gut microbiota have been found. Heavy metal exposure disrupts gut microbiota and influences its metabolism and physiological functions, potentially contributing to metabolic and other disorders. Furthermore, gut microbiota influences the absorption and metabolism of heavy metals by serving as a physical barrier against heavy metal absorption and modulating the pH, oxidative balance, and concentrations of detoxification enzymes or proteins involved in heavy metal metabolism. The interactions between heavy metals and gut microbiota might be positive or negative according to different valence states, concentrations, and forms of the same heavy metal. This paper reviews the metabolic interactions of 10 common heavy metals with the gut microbiota and their health implications. This collated information could provide novel insights into the disruption of the intestinal microbiota caused by heavy metals as a potential contributing factor to human diseases.

Chemical Analysis and Molecular Modelling of Cyclodextrin-Formulated Propofol and Its Sodium Salt to Improve Drug Solubility, Stability and Pharmacokinetics (Cytogenotoxicity)

Propofol is a widely used general anesthetic in clinical practice, but its use is limited by its water-insoluble nature and associated pharmacokinetic and pharmacodynamic limitations. Therefore, researchers have been searching for alternative formulations to lipid emulsion to address the remaining side effects. In this study, novel formulations for propofol and its sodium salt Na-propofolat were designed and tested using the amphiphilic cyclodextrin (CD) derivative hydroxypropyl-β-cyclodextrin (HPβCD). The study found that spectroscopic and calorimetric measurements suggested complex formation between propofol/Na-propofolate and HPβCD, which was confirmed by the absence of an evaporation peak and different glass transition temperatures. Moreover, the formulated compounds showed no cytotoxicity and genotoxicity compared to the reference. The molecular modeling simulations based on molecular docking predicted a higher affinity for propofol/HPβCD than for Na-propofolate/HPβCD, as the former complex was more stable. This finding was further confirmed by high-performance liquid chromatography. In conclusion, the CD-based formulations of propofol and its sodium salt may be a promising option and a plausible alternative to conventional lipid emulsions.

Cationic cellulose nanocrystals as sustainable green material for multi biological applications via ξ potential

The present study aims to disclose the activity of cationic cellulose nanocrystals (CNCs) as a promising multifunctional green nanomaterial with applications in biological aspects. The basic reason behind multifunctional behavior is zeta potential and size distribution of nano biopolymers; exhibit a remarkable physical and biological activity compared to normal molecules.The preliminary characterized studied using absorption spectral analysis showed strong absorption peak indicating that spectrum curves can be screen by UV spectra at wavelength range 200-400nm. Ultrastructural studies (SEM-EDS and TEM), manifest that CNCs are elliptical particles in shape. Also, TEM show CNCs are the ideal illustration of zero-dimensional (0-D) NPs, less than 5.1 nm in diameter with Cationic charge and similar results in size distribution by TEM. Nonetheless, developed as antioxidant activity IC₅₀ was 1467 ± 25.9 µg/mL, antimicrobial activity tested G^-ve strains, but not affected on tested G^+ve strains and tested fungi. Evaluating toxicity effect of cationic CNCs against human blood erythrocytes (RBCs) and Lymphocyte Proliferation and the end point evaluate by comet assay, which proven no cytotoxic effect. Also, a high dose 500 µg/mL of CNCs highly significant (p < 0.05) reduction in cell viability of Caco-2 cancer cells after 24 h. incubation time, whereas the IC₅₀ was 1884 ± 19.46 µg/mL. Moreover, genotoxic assay indicates Caco-2 cells cause apoptosis with no fragmentation in DNA. Undoubtedly, the obtained results brought about by the interaction of layers carrying opposing charges. Additionally, there is a balance between hydrophilic contact and electrostatic attraction. That emphasizes how the cationic CNCs have excellent potential for use as antioxidants, antimicrobials, and anticancer agents.

An Insight into the Impact of Serum Tellurium, Thallium, Osmium and Antimony on the Antioxidant/Redox Status of PCOS Patients: A Comprehensive Study

Humans exploit heavy metals for various industrial and economic reasons. Although some heavy metals are essential for normal physiology, others such as Tellurium (Te), Thallium (TI), antimony (Sb), and Osmium (Os) are highly toxic and can lead to Polycystic Ovarian Syndrome (PCOS), a common female factor of infertility. The current study was undertaken to determine levels of the heavy metals TI, Te, Sb and Os in serum of PCOS females (n = 50) compared to healthy non-PCOS controls (n = 56), and to relate such levels with Total Antioxidant Capacity (TAC), activity of key antioxidant enzymes, oxidative stress marker levels and redox status. PCOS serum samples demonstrated significantly higher levels of TI, Te, Sb and Os and diminished TAC compared to control (p < 0.001). Furthermore, there was significant inhibition of SOD, CAT and several glutathione-related enzyme activities in sera of PCOS patients with concurrent elevations in superoxide anions, hydrogen and lipid peroxides, and protein carbonyls, along with disrupted glutathione homeostasis compared to those of controls (p < 0.001 for all parameters). Additionally, a significant negative correlation was found between the elevated levels of heavy metals and TAC, indicative of the role of metal-induced oxidative stress as a prominent phenomenon associated with the pathophysiology of the underlying PCOS. Data obtained in the study suggest toxic metals as risk factors causing PCOS, and thus protective measures should be considered to minimize exposure to prevent such reproductive anomalies.

Microbiome enrichment from contaminated marine sediments unveils novel bacterial strains for petroleum hydrocarbon and heavy metal bioremediation

Petroleum hydrocarbons and heavy metals are some of the most widespread contaminants affecting marine ecosystems, urgently needing effective and sustainable remediation solutions. Microbial-based bioremediation is gaining increasing interest as an effective, economically and environmentally sustainable strategy. Here, we hypothesized that the heavily polluted coastal area facing the Sarno River mouth, which discharges >3 tons of polycyclic aromatic hydrocarbons (PAHs) and ∼15 tons of heavy metals (HMs) into the sea annually, hosts unique microbiomes including marine bacteria useful for PAHs and HMs bioremediation. We thus enriched the microbiome of marine sediments, contextually selecting for HM-resistant bacteria. The enriched mixed bacterial culture was subjected to whole-DNA sequencing, metagenome-assembled-genomes (MAGs) annotation, and further sub-culturing to obtain the major bacterial species as pure strains. We obtained two novel isolates corresponding to the two most abundant MAGs (Alcanivorax xenomutans strain-SRM1 and Halomonas alkaliantarctica strain-SRM2), and tested their ability to degrade PAHs and remove HMs. Both strains exhibited high PAHs degradation (60-100%) and HMs removal (21-100%) yield, and we described in detail >60 genes in their MAGs to unveil the possible genetic basis for such abilities. Most promising yields (∼100%) were obtained towards naphthalene, pyrene and lead. We propose these novel bacterial strains and related genetic repertoire to be further exploited for effective bioremediation of marine environments contaminated with both PAHs and HMs.

Toxicological and Nutraceutical Screening Assays of Some Artificial Sweeteners

Artificial sweeteners are food additives worldwide used instead of fructose or glucose in many diet beverages. Furthermore, diet beverages intake has been increasing every year. Thus, some food agencies should regulate it based on toxicological studies. Debates and controversial results are demonstrated, and authority can revise its decision on the basis of new data reporting toxicological effects since cyclamate has been forbidden in some countries. Therefore, the aim of this study was to report new data about the toxicity of acesulfame-k, aspartame, and cyclamate, which are useful for authority agencies, determining the toxic potential and nutraceutical capabilities of these compounds. The toxicity, antitoxicity, genotoxicity, antigenotoxicity, and life expectancy assays were carried out in Drosophila as an in vivo model. In addition, in vitro HL-60 line cell was used to evaluate the chemopreventive activity determining the cytotoxic effect and the capability of producing DNA damage due to internucleosomal fragmentation or DNA strand breaks. Furthermore, the methylated status of these cancer cells treated with the tested compounds was assayed as a cancer therapy. Our results demonstrated that all tested compounds were neither toxic nor genotoxic, whereas these compounds resulted in antigenotoxic and cytotoxic substances, except for cyclamate. Aspartame showed antitoxic effects in Drosophila. All tested compounds decreased the quality of life of this in vivo organism model. Acesulfame-k, aspartame, and cyclamate induced DNA damage in the HL-60 cell line in the comet assay, and acesulfame-k generally increased the methylation status. In conclusion, all tested artificial sweeteners were safe compounds at assayed concentrations since toxicity and genotoxicity were not significantly induced in flies. Moreover, Aspartame and Cyclamate showed protective activity against a genotoxin in Drosophila Regarding nutraceutical potential, acesulfame-k and aspartame could be demonstrated to be chemopreventive due to the cytotoxicity activity shown by these compounds. According to DNA fragmentation and comet assays, a necrotic way could be the main mechanism of death cells induced by acesulfame-k and aspartame. Finally, Acesulfame-K hypermethylated repetitive elements, which are hypomethylated in cancer cells resulting in a benefit to humans.

Phytoremediation technology and food security impacts of heavy metal contaminated soils: A review of literature

Heavy metal accumulation in soil and water is one of major problems caused by inorganic contaminants. Their presence in agricultural soils in high quantities have impacted the food security significantly and, by extension, the human health. Amongst various physico-chemical methods available for remediation of heavy-metals-polluted-sites, phytoremediation approaches have been found to be safe and environment friendly. This review gathered scattered information on heavy metal phytoremediation studies published in both review and research articles. It described the impact of heavy metals on food security and comprehensively discussed the application of different phytoremediation approaches for treatment of heavy metal-polluted soils, the basic principles underlining them, their strengths and weaknesses. Our findings indicated that, while hundreds of hyper-accumulator plants are being reported yearly, only few describe limitations inherent in them, such as low growth rate, low biomass production, and low metal tolerance. Hence, this review also gave a detailed overview of research gaps in phytotechnology and advocates consideration of the 'omics' studies; genomics, proteomics, metabolomics and likes in selecting and enhancing potential plants for phytoremediation. For a sustainable large-scale phytoremediation application, we established a multi-technology repair strategy via the combination of different methods like application of biological composts, plant-growth promoting microorganisms, and phytohormones for stimulation of the plant-growth during phytoremediation. We also gave comprehensive insights to proper disposal of plants used for phytoremediation, this subject is often not well considered/planned while deciding the application of plants for removal of heavy metals from polluted environments.

Protective effect of hawthorn vitexin on the ethanol-injured DNA of BRL-3A hepatocytes

ABSTRACT

Vitexin is a natural active ingredient in hawthorn leaves, which has a wide range of anti-tumor effects. This study was conducted to assess the protective effect of hawthorn vitexin on the ethanol-injured DNA of hepatocytes in vitro and to explore its mechanism. The effect of different concentrations of hawthorn vitexin on ethanol-injured hepatocytes was detected via the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method to study the protective effect of hawthorn vitexin on ethanol-injured DNA damage in hepatocytes. Single-cell gel electrophoresis was used to observe the effect of hawthorn vitexin on ethanol-induced DNA damage in hepatocytes, and the Olive tail moment was measured. Cell physiological and biochemical indexes, such as superoxide dismutase activity, malonaldehyde content, and glutathione peroxidase activity, were detected with kits. The mRNA expression of the superoxide dismutase gene was measured via real-time quantitative polymerase chain reaction. It was showed that 0.2, 0.4, and 0.8 mg mL-1 hawthorn vitexin could significantly repair hepatocyte growth and ethanol-induced DNA damage. This effect was closely related to the improvement in superoxide dismutase, malonaldehyde, and glutathione peroxidase. Hawthorn vitexin could be used to repair ethanol-injured hepatocytes through antioxidation effects, and showed potential for the treatment of liver injury.

Antioxidant status in relation to heavy metals induced oxidative stress in patients with polycystic ovarian syndrome (PCOS)

Polycystic ovary syndrome (PCOS) is a global health concern for women of reproductive age, as 6.5% of women worldwide are affected by this syndrome. PCOS is marked by hyperandrogenism, anovulation, menstrual abnormalities, and polycystic ovaries. Metals such as arsenic, cadmium, lead and mercury are considered to be systemic toxicants/human carcinogens and seem to have devastating effects on humans, even at minimal exposures. One of the probable aetiological factors for PCOS has been identified as oxidative stress. In view of the probable associations among oxidative stress, metal toxicity and PCOS, the present study examined the role of heavy metals in the generation of oxidative stress among females. This prospective study included 106 women (56 women diagnosed with PCOS and 50 women who were not diagnosed with PCOS as control women). There were no significant differences in the sociodemographic characteristics between the two groups except for the irregularity of menses and the presence of acne. The serum As, Cd, Pb, and Hg levels increased and the serum glutathione (GSH) and superoxide dismutase (SOD) levels diminished significantly in the PCOS group compared to the control group at P < 0.001. The SOD levels were negatively correlated with the As and Pb levels at P < 0.05. Additionally, the PCOS group exhibited a strong negative correlation between the GSH and As levels (P < 0.01), GSH and Pb levels (P < 0.05) and GSH and Hg levels (P < 0.01). Furthermore, the As levels were positively correlated with increased levels of Cd, Pb and Hg among PCOS women. Significant positive correlations were observed between Pb and Cd and between Cd and Hg at P < 0.001. The outcome of the study provides clear insight into the role of metal-induced oxidative stress, which plays a vital role in the pathophysiology underlying PCOS and suggests the use of these markers as prognostic tools to reduce the consequences of high-risk exposure to these metals among females.

Removal of Heavy Metal Ions from Wastewaters: An Application of Sodium Trithiocarbonate and Wastewater Toxicity Assessment

The synthesis and application of sodium trithiocarbonate (Na2CS3) for the treatment of real galvanic wastewater in order to remove heavy metals (Cu, Cd and Zn) was investigated. A Central Composite Design/Response Surface Methodology (CCD/RSM) was employed to optimize the removal of heavy metals from industrial wastewater. Adequacy of approximated data was verified using Analysis of Variance (ANOVA). The calculated coefficients of determination (R2 and R2adj) were 0.9119 and 0.8532, respectively. Application of Na2CS3 conjugated with CCD/RSM allowed Cu, Cd and Zn levels to be decreased and, as a consequence, ∑Cu,Cd,Zn decreased by 99.80%, 97.78%, 99.78%, and 99.69%, respectively, by using Na2CS3 at 533 mg/L and pH 9.7, within 23 min. Implementation of conventional metal precipitation reagents (NaOH, Ca(OH)2 and CaO) at pH 11 within 23 min only decreased ∑Cu,Cd,Zn by 90.84%, 93.97% and 93.71%, respectively. Rotifer Brachionus plicatilis was used to conduct the assessment of wastewater toxicity. Following the application of Na2CS3, after 60 min the mortality of B. plicatilis was reduced from 90% to 25%. Engagement of Na2CS3 under optimal conditions caused the precipitation of heavy metals from the polluted wastewater and significantly decreased wastewater toxicity. In summary, Na2CS3 can be used as an effective heavy metal precipitating agent, especially for Cu, Cd and Zn.

Degradation of Hydrocarbons and Heavy Metal Reduction by Marine Bacteria in Highly Contaminated Sediments

Investigations on the ability of bacteria to enhance removal of hydrocarbons and reduce heavy metal toxicity in sediments are necessary to design more effective bioremediation strategies. In this study, five bacterial strains, Halomonas sp. SZN1, Alcanivorax sp. SZN2, Pseudoalteromonas sp. SZN3, Epibacterium sp. SZN4, and Virgibacillus sp. SZN7, were isolated from polluted sediments from an abandoned industrial site in the Gulf of Naples, Mediterranean Sea, and tested for their bioremediation efficiency on sediment samples collected from the same site. These bacteria were added as consortia or as individual cultures into polluted sediments to assess biodegradation efficiency of polycyclic aromatic hydrocarbons and heavy metal immobilisation capacity. Our results indicate that these bacteria were able to remove polycyclic aromatic hydrocarbons, with a removal rate up to ca. 80% for dibenzo-anthracene. In addition, these bacteria reduced arsenic, lead, and cadmium mobility by promoting their partitioning into less mobile and bioavailable fractions. Microbial consortia generally showed higher performance toward pollutants as compared with pure isolates, suggesting potential synergistic interactions able to enhance bioremediation capacity. Overall, our findings suggest that highly polluted sediments select for bacteria efficient at reducing the toxicity of hazardous compounds, paving the way for scaled-up bioremediation trials.

Arsenic hampered embryonic development: An in vivo study using local Bangladeshi Danio rerio model

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Exposure to arsenic results delayed and deformed embryonic development.

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Arsenic exposure increased the mortality rate of embryos.

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Arsenic exposure may increase miscarriage or abortion rate in the pregnant mother.

Zebrafish (Danio rerio) has appeared as a valuable and popular model species to study the developmental and toxicological impact of environmental pollutants. To get insights on the toxicological effect of arsenic on early embryonic development, a controlled breeding of local Bangladeshi zebrafish followed by comprehensive microscopic analysis was conducted to study the embryonic development after exposure to different concentrations of arsenic ranges from 4−120 h post-fertilization. Zebrafish embryos exposed to 2 mM of arsenic displayed distinguishable developmental delay compared to control. At three days post-fertilization, a distinct phenotype appears in arsenic-treated embryos, which can be characterized by dechorionated embryos, larger egg mass, pericardial edema, abnormal heart rate, and abnormal head development. Remarkably, the death rate of the arsenic-treated embryos was significantly higher compared to control. Collectively, these findings indicate that exposure to arsenic may result in abnormal embryonic development. These results suggest for proper management of the pregnant mother in the arsenic-exposed area, and may also explain the incidence of increased miscarriage/abortion rate in arsenic water drinking pregnant mother.

Comparative Gene Expression Profiling of Tobacco-Associated HPV-Positive versus Negative Oral Squamous Carcinoma Cell Lines

Background: HPV-positive oral squamous cell carcinomas (OSCCs) are specific biological and clinical entities, characterized by a more favorable prognosis compared to HPV-negative OSCCs and occurring generally in non-smoking and non-drinking younger individuals. However, poor information is available on the molecular and the clinical behavior of HPV-positive oral cancers occurring in smoking/drinking subjects. Thus, this study was designed to compare, at molecular level, two OSCC cell lines, both derived from drinking and smoking individuals and differing for presence/absence of HPV infection. Methods: HPV-negative UPCI-SCC-131 and HPV16-positive UPCI-SCC-154 cell lines were compared by whole genome gene expression profiling and subsequently studied for activation of Wnt/βCatenin signaling pathway by the expression of several Wnt-target genes, βCatenin intracellular localization, stem cell features and miRNA let-7e. Gene expression data were validated in head and neck squamous cell carcinoma (HNSCC) public datasets. Results: Gene expression analysis identified Wnt/βCatenin pathway as the unique signaling pathway more active in HPV-negative compared to HPV-positive OSCC cells and this observation was confirmed upon evaluation of several Wnt-target genes (i.e., Cyclin D1, Cdh1, Cdkn2a, Cd44, Axin2, c-Myc and Tcf1). Interestingly, HPV-negative OSCC cells showed higher levels of total βCatenin and its active form, increase of its nuclear accumulation and more prominent stem cell traits. Furthermore, miRNA let-7e was identified as potential upstream regulator responsible for the downregulation of Wnt/βCatenin signaling cascade since its silencing in UPCI-SCC-154 cell resulted in upregulation of Wnt-target genes. Finally, the analysis of two independent gene expression public datasets of human HNSCC cell lines and tumors confirmed that Wnt/βCatenin pathway is more active in HPV-negative compared to HPV-positive tumors derived from individuals with smoking habit. Conclusions: These data suggest that lack of HPV infection is associated with more prominent activation of Wnt/βCatenin signaling pathway and gain of stem-like traits in tobacco-related OSCCs.

Non-canonical Hedgehog Signaling Pathway in Cancer: Activation of GLI Transcription Factors Beyond Smoothened

The Hedgehog-GLI (HH-GLI) pathway is a highly conserved signaling that plays a critical role in controlling cell specification, cell–cell interaction and tissue patterning during embryonic development. Canonical activation of HH-GLI signaling occurs through binding of HH ligands to the twelve-pass transmembrane receptor Patched 1 (PTCH1), which derepresses the seven-pass transmembrane G protein-coupled receptor Smoothened (SMO). Thus, active SMO initiates a complex intracellular cascade that leads to the activation of the three GLI transcription factors, the final effectors of the HH-GLI pathway. Aberrant activation of this signaling has been implicated in a wide variety of tumors, such as those of the brain, skin, breast, gastrointestinal, lung, pancreas, prostate and ovary. In several of these cases, activation of HH-GLI signaling is mediated by overproduction of HH ligands (e.g., prostate cancer), loss-of-function mutations in PTCH1 or gain-of-function mutations in SMO, which occur in the majority of basal cell carcinoma (BCC), SHH-subtype medulloblastoma and rhabdomyosarcoma. Besides the classical canonical ligand-PTCH1-SMO route, mounting evidence points toward additional, non-canonical ways of GLI activation in cancer. By non-canonical we refer to all those mechanisms of activation of the GLI transcription factors occurring independently of SMO. Often, in a given cancer type canonical and non-canonical activation of HH-GLI signaling co-exist, and in some cancer types, more than one mechanism of non-canonical activation may occur. Tumors harboring non-canonical HH-GLI signaling are less sensitive to SMO inhibition, posing a threat for therapeutic efficacy of these antagonists. Here we will review the most recent findings on the involvement of alternative signaling pathways in inducing GLI activity in cancer and stem cells. We will also discuss the rationale of targeting these oncogenic pathways in combination with HH-GLI inhibitors as a promising anti-cancer therapies.

An Overview on Arsenic Trioxide-Induced Cardiotoxicity

Arsenic trioxide (ATO) is among the first-line chemotherapeutic drugs used in oncological practice. It has shown substantial efficacy in treating patients with relapsed or refractory acute promyelocytic leukaemia. The clinical use of ATO is hampered due to cardiotoxicity and hence many patients are precluded from receiving this highly effective treatment. An alternative to this would be to use any drug that can ameliorate the cardiotoxic effects and allow exploiting the full therapeutic potential of ATO, with considerable impact on cancer therapy. Generation of reactive oxygen species is involved in a wide range of human diseases, including cancer, cardiovascular, pulmonary and neurological disorders. Hence, agents with the ability to protect against these reactive species may be therapeutically useful. The present review focuses on the beneficial as well as harmful effects of arsenic and ATO, the mechanisms underlying ATO toxicity and the possible ways that can be adopted to circumvent ATO-induced toxicity.

Substantial Evidences Indicate That Inorganic Arsenic Is a Genotoxic Carcinogen: a Review

Arsenic is one of the most toxic environmental toxicants. More than 150 million people worldwide are exposed to arsenic through ground water contamination. It is an exclusive human carcinogen. Although the hallmarks of arsenic toxicity are skin lesions and skin cancers, arsenic can also induce cancers in the lung, liver, kidney, urinary bladder, and other internal organs. Arsenic is a non-mutagenic compound but can induce significant cytogenetic damage as measured by chromosomal aberrations, sister chromatid exchanges, and micronuclei formation in human systems. These genotoxic end points are extensively used to predict genotoxic potentials of different environmental chemicals, drugs, pesticides, and insecticides. These cytogenetic end points are also used for evaluating cancer risk. Here, by critically reviewing and analyzing the existing literature, we conclude that inorganic arsenic is a genotoxic carcinogen.

VERNONIA AMYGDALINA DELILE EXHIBITS A POTENTIAL FOR THE TREATMENT OF ACUTE PROMYELOCYTIC LEUKEMIA

The World Health Organization (WHO) has been on front line to encourage developing countries to identify medicinal plants that are safe and easily available to patients. Traditional medicine represents the first-treatment choice for the healthcare of approximately 80% of people living in developing countries. Also, its use in the United States has increased by 38% during within the last decade of the 20^th century alone. Therefore, the aim of the present study was to explore the efficacy of a medicinal plant, Vernonia amygdalina Delile (VAD), as a new targeted therapy for the management of acute promyelocytic leukemia (APL), using HL-60 cells as a test model. To address our specific aim, HL-60 promyelocytic leukemia cells were treated with VAD. Live and dead cells were determined by acridine orange and propidium iodide (AO/PI) dye using the Cellometer Vision. The extent of DNA damage was evaluated by the comet assay. Cell apoptosis was evaluated by flow cytometry assessment. Data obtained from the AO/PI assay indicated that VAD significantly reduced the number of live cells in a dose-dependent manner, showing a gradual increase in the loss of viability in VAD-treated cells. We observed a significant increase in DNA damage in VAD-treated cells compared to the control group. Flow cytometry data demonstrated that VAD induced apoptosis in treated cells compared to the control cells. These results suggest that induction of cell death, DNA damage, and cell apoptosis are involved in the therapeutic efficacy of VAD. Because VAD exerts anticancer activity in vitro, it would be interesting to perform clinical trials to confirm its effectiveness as an anticancer agent towards the treatment of APL patients.

Anti/genotoxic, longevity inductive, cytotoxic, and clastogenic-related bioactivities of tomato and lycopene

The aim of this study was to evaluate some biological activities of tomato as well as lycopene and to consider a new nutraceutic value for this fruit regarding to the protection against genetic damage and as a chemopreventive agent. Genotoxicity, DNA-protection against hydrogen peroxide, and lifespan properties of tomato and lycopene were assessed through wing spot test and longevity assay using the Drosophila in vivo model. Additionally, chemopreventive activity was investigated through cytotoxicity, DNA-fragmentation comet and annexin V FITC/PI assays using HL60 in vitro model. Results showed that: (i) tomato and lycopene are not genotoxic and protect against H₂ O₂ -induced damage; (ii) with respect to the lifespan, tomato and lycopene are harmless at the lowest concentration; (iii) tomato is cytotoxic in a dose-dependent manner, but not lycopene; (iv) tomato and lycopene do not induce internucleosomal DNA-fragmentation although they induce significant clastogenic activity at low level in the leukemia cells. To sum up, tomato is a good candidate to be considered as a nutraceutical substance. Furthermore, synergistic action among other components within tomato matrix could be the cause of the health effects observed in this vegetable, which are not fully explained by lycopene. Environ. Mol. Mutagen. 59:427-437, 2018. © 2018 Wiley Periodicals, Inc.

Therapeutic Mechanisms of Vernonia amygdalina Delile in the Treatment of Prostate Cancer

Prostate cancer patients have been suffering from limited treatment options due to late diagnosis, poor drug tolerance, and multi-drug resistance to almost all the current drug treatments. Therefore, it is important to seek a new alternative therapeutic medicine that can effectively prevent the disease and even eradicate the progression and metastasis of prostate cancer. Vernonia amygdalina Delile (VAD) is a common edible vegetable in Cameroon that has been used as a traditional medicine for some human diseases. However, to the best of our knowledge, no previous reports have explored its therapeutic efficacy against human prostate cancer. The objective of the present study was to assess the anticancer activities of VAD methanolic extracts in the prevention and treatment of prostate cancer using human androgen-independent prostate cancer (PC-3) cells as a test model. To achieve our objective, PC-3 cells were treated with various doses of VAD for 48 h. Data generated from the trypan blue test and MTT assay demonstrated that VAD extracts exhibited significant growth-inhibitory effects on PC-3 cells. Collectively, we established for the first time the antiproliferative effects of VAD on PC-3 cells, with an IC50 value of about 196.6 µg/mL. Further experiments, including cell morphology, lipid peroxidation and comet assays, and apoptosis analysis showed that VAD caused growth-inhibitory effects on PC-3 cells through the induction of cell growth arrest, DNA damage, apoptosis, and necrosis in vitro and may provide protection from oxidative stress diseases as a result of its high antioxidant content. These results provide useful data on the anticancer activities of VAD for prostate cancer and demonstrate the novel possibilities of this medicinal plant for developing prostate cancer therapies.

Clinical effects of chemical exposures on mitochondrial function

Mitochondria are critical for the provision of ATP for cellular energy requirements. Tissue and organ functions are dependent on adequate ATP production, especially when energy demand is high. Mitochondria also play a role in a vast array of important biochemical pathways including apoptosis, generation and detoxification of reactive oxygen species, intracellular calcium regulation, steroid hormone and heme synthesis, and lipid metabolism. The complexity of mitochondrial structure and function facilitates its diverse roles but also enhances its vulnerability. Primary disorders of mitochondrial bioenergetics, or Primary Mitochondrial Diseases (PMD) are due to inherited genetic defects in the nuclear or mitochondrial genomes that result in defective oxidative phosphorylation capacity and cellular energy production. Secondary mitochondrial dysfunction is observed in a wide range of diseases such as Alzheimer's and Parkinson's disease. Several lines of evidence suggest that environmental exposures cause substantial mitochondrial dysfunction. Whereby literature from experimental and human studies on exposures associated with Alzheimer's and Parkinson's diseases exist, the significance of exposures as potential triggers in Primary Mitochondrial Disease (PMD) is an emerging clinical question that has not been systematically studied.

Cytotoxicity and genotoxicity effects of arsenic trioxide on SQ20B human laryngeal carcinoma cells

This study investigates the cytotoxicity and the genotoxicity induced by arsenic trioxide As₂O₃in human laryngeal SQ20B carcinoma cell line. SQ20B cells were exposed to graded concentrations of arsenic trioxide (2 and 5μM) for 48h. Comet assay and γ-H2AX foci formation were used for measuring DNA damages, flow cytometry was used to identify cell cycle alterations and apoptosis, while cell morphology was visualized using transmission electron microscopy. The results show a dose-dependent induction of DNA damages and double strand breaks, alterations in cell cycle and morphologic alterations of cells. These results prove that As₂O₃ is highly cytotoxic and genotoxic at the micromolar range ina human laryngeal carcinoma cell line.

Arsenic in the groundwater: Occurrence, toxicological activities, and remedies

Arsenic (As) contamination in groundwater has become a geo-environmental as well as a toxicological problem across the globe affecting more than 100-million people in nearly 21 countries with its associated disease "arsenicosis." Arsenic poisoning may lead to fatal skin and internal cancers. In present review, an attempt has been made to generate awareness among the readers about various sources of occurrence of arsenic, its geochemistry and speciation, mobilization, metabolism, genotoxicity, and toxicological exposure on humans. The article also emphasizes the possible remedies for combating the problem. The knowledge of these facts may help to work on some workable remedial measure.

Arsenic trioxide induces ROS activity and DNA damage, leading to G0/G1 extension in skin fibroblasts through the ATM-ATR-associated Chk pathway

Arsenic (As) toxicity is a global health problem, affecting millions of people. Exposure to arsenic, mostly via drinking water, has been associated with cancer of skin, lungs, and blood, in addition to several kinds of skin lesions. The present study focused on the effect of arsenic trioxide (As₂O₃) on normal skin fibroblast cells. Specifically, the effect of As₂O₃ on ROS generation and oxidative stress was investigated. Proteins involved in the DNA damage signaling pathway and cell cycle were also studied. As₂O₃ induced the generation of intracellular ROS. Immunohistochemistry analysis revealed a dose-dependent increase in the number of 8-OHdG-positive cells, an indication of oxidative stress. Cell cycle analysis by flow cytometry demonstrated that As₂O₃ caused a significant percentage of cells to accumulate in the G0/G1 phase with a concomitant reduction in the S phase. Increases in the activated forms of DNA damage signaling proteins, ATM and ATR, and their effector molecules, Chk2 and p53, were also observed. In addition, expression of oncogene p21 was also increased. The study shows that exposure of normal skin fibroblast cells to As₂O₃ could lead to cell cycle arrest through ATM/ATR and DNA damage signaling pathways. In conclusion, we report here that arsenic trioxide increases cellular oxidative stress leading to shift in cell cycle and leads to DNA damage through ATM/ATR and the CHK-dependent signaling pathway.

Therapeutic Potential of Arsenic Trioxide (ATO) in Treatment of Hepatocellular Carcinoma: Role of Oxidative Stress in ATO-Induced Apoptosis

Hepatocellular carcinoma (HCC), the dominant form of primary liver cancer, is the sixth most common cancer in the world with more than 700,000 people diagnosed annually. Arsenic trioxide (ATO) has been shown to be a potent anticancer agent in various carcinomas, proving particularly effective in the clinical treatment of relapsed and refractory acute promyelocytic leukemia. However, its bioactivity and molecular mechanisms against HCC has not been fully studied. Using human HCC (HepG2) cells as a test model, we studied the effects of ATO and examined the role of oxidative stress (OS) and apoptosis in cytotoxicity. OS biomarkers showed a significant increase (p< 0.05) of malondialdehyde concentrations, and a gradual decrease of antioxidant enzymes (GPx & CAT) activities with increasing ATO doses. Flow cytometry data showed a dose dependent increase in annex in V positive cells and caspase 3 activities. These results were confirmed by data of the DNA laddering assay showing a clear evidence of nucleosomal DNA fragmentation, as well as data from Western blotting showing a significant modulation of specific apoptotic related proteins, including the activation of p53 and p21 expression and the down-regulation of Bcl-2 expression in ATO-treated cells. Taken together, our research demonstrates that ATO has a potential therapeutic effect against HCC, and its cytotoxicity may be mediated via oxidative stress and activation of the mitochondrial or intrinsic pathway of apoptosis.

The Role of Oxidative Stress in Koenimbine-Induced DNA Damage and Heat Shock Protein Modulation in HepG2 Cells

Background. Murraya koenigii (L.) Spreng, is a significant herb of traditional Ayurvedic system of medicine. Koenimbine, a carbazole alkaloid isolated from this plant holds antiproliferative and apoptotic effects. The aim of this study was to assess koenimbine-induced DNA damage and to clarify the role of free radicals in cell death mechanisms, using HepG2 cells. Methods. The level of cytotoxicity was assayed by MTT assay. To elucidate the role of glutathione (GSH), the intracellular GSH level was analyzed. The effect of koenimbine in the cell mitochondria was evaluated using mitochondrial membrane potential (MMP) changes. Single cell gel electrophoresis assay was used to examine the level of DNA damage. Heat shock proteins, Hsp 70 and Hsp 90 expressions were checked at mRNA and protein level. Ascorbic acid and catalase were used as control antioxidants. Results. It was observed that koenimbine considerably increased DNA damage in HepG2 cells at subcytotoxic concentrations. Koenimbine induced the increased levels of reactive oxygen species (ROS) and reduction of GSH level in HepG2 cells, together with time-dependent loss of MMP. In addition, results clearly showed that koenimbine encouraged cells to express Hsp 70 and Hsp 90 in a concentration-dependent manner up to a concentration of 100 µM and a time-dependent manner at 24-hour incubation both at transcriptional and translational levels. The antioxidant capacity of ascorbic acid was found to be not as prominent as to catalase throughout the study. Conclusion. Based on these data it can be concluded that koenimbine causes DNA strand breaks in HepG2 cells, probably through oxidative stress. Moreover, the oxidative stress induced was closely associated with MMP reduction and GSH depletion associated with HSP modulation at subcytotoxic concentration.

In Vivo and In Vitro Genotoxic and Epigenetic Effects of Two Types of Cola Beverages and Caffeine: A Multiassay Approach

The aim of this work was to assess the biological and food safety of two different beverages: Classic Coca Cola™ (CCC) and Caffeine-Free Coca Cola (CFCC). To this end, we determined the genotoxicological and biological effects of different doses of lyophilised CCC and CFCC and Caffeine (CAF), the main distinctive constituent. Their toxic/antitoxic, genotoxic/antigenotoxic, and chronic toxicity (lifespan assay) effects were determined in vivo using the Drosophila model. Their cytotoxic activities were determined using the HL-60 in vitro cancer model. In addition, clastogenic DNA toxicity was measured using internucleosomal fragmentation and SCGE assays. Their epigenetic effects were assessed on the HL-60 methylation status using some repetitive elements. The experimental results showed a slight chemopreventive effect of the two cola beverages against HL-60 leukaemia cells, probably mediated by nonapoptotic mechanisms. Finally, CCC and CAF induced a global genome hypomethylation evaluated in LINE-1 and Alu M1 repetitive elements. Overall, we demonstrated for the first time the safety of this famous beverage in in vivo and in vitro models.

Nickel-Refining Fumes Induced DNA Damage and Apoptosis of NIH/3T3 Cells via Oxidative Stress

Although there have been numerous studies examining the toxicity and carcinogenicity of nickel compounds in humans and animals, its molecular mechanisms of action are not fully elucidated. In our research, NIH/3T3 cells were exposed to nickel-refining fumes at the concentrations of 0, 6.25, 12.50, 25, 50 and 100 μg/mL for 24 h. Cell viability, cell apoptosis, reactive oxygen species (ROS) level, lactate dehydrogenase (LDH) assay, the level of glutathione (GSH), activities of superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA) level were detected. The exposure of NIH/3T3 cells to nickel-refining fumes significantly reduced cell viability and induced cell apoptotic death in a dose-dependent manner. Nickel-refining fumes significantly increased ROS levels and induced DNA damage. Nickel-refining fumes may induce the changes in the state of ROS, which may eventually initiate oxidative stress, DNA damage and apoptosis of NIH/3T3 cells.

Endoplasmic reticulum stress contributes to arsenic trioxide-induced intrinsic apoptosis in human umbilical and bone marrow mesenchymal stem cells

Arsenic trioxide is an old drug and has been used for a long time in traditional Chinese and Western medicines. However, the cancer treatment of arsenic trioxide has heart and vascular toxicity. The cytotoxic effects of arsenic trioxide and its molecular mechanism in human umbilical mesenchymal stem cells (HUMSC) and human bone marrow-derived mesenchymal stem cells (HMSC-bm) were investigated in this study. Our results showed that arsenic trioxide significantly reduced the viability of HUMSC and HMSC-bm in a concentration- and time-dependent manner. Arsenic trioxide is able to induce apoptotic cell death in HUMSC and HMSC-bm, as shown from the results of morphological examination, flow cytometric analyses, DAPI staining and comet assay. The appearance of arsenic trioxide also led to an increase of intracellular free calcium (Ca(2+) ) concentration and the disruption of mitochondrial membrane potential (ΔΨm). The caspase-9 and caspase-3 activities were time-dependently increased in arsenic trioxide-treated HUMSC and HMSC-bm. In addition, the proteomic analysis and DNA microarray were carried out to investigate the expression level changes of genes and proteins affected by arsenic trioxide treatment in HUMSC. Our results suggest that arsenic trioxide induces a prompt induction of ER stress and mitochondria-modulated apoptosis in HUMSC and HMSC-bm. A framework was proposed for the effect of arsenic trioxide cytotoxicity by targeting ER stress.

Cadmium Chloride Induces DNA Damage and Apoptosis of Human Liver Carcinoma Cells via Oxidative Stress

Cadmium is a heavy metal that has been shown to cause its toxicity in humans and animals. Many documented studies have shown that cadmium produces various genotoxic effects such as DNA damage and chromosomal aberrations. Ailments such as bone disease, renal damage, and several forms of cancer are attributed to overexposure to cadmium. Although there have been numerous studies examining the effects of cadmium in animal models and a few case studies involving communities where cadmium contamination has occurred, its molecular mechanisms of action are not fully elucidated. In this research, we hypothesized that oxidative stress plays a key role in cadmium chloride-induced toxicity, DNA damage, and apoptosis of human liver carcinoma (HepG₂) cells. To test our hypothesis, cell viability was determined by MTT assay. Lipid hydroperoxide content stress was estimated by lipid peroxidation assay. Genotoxic damage was tested by the means of alkaline single cell gel electrophoresis (Comet) assay. Cell apoptosis was measured by flow cytometry assessment (Annexin-V/PI assay). The result of MTT assay indicated that cadmium chloride induces toxicity to HepG₂ cells in a concentration-dependent manner, showing a 48 hr-LD50 of 3.6 µg/mL. Data generated from lipid peroxidation assay resulted in a significant (p < 0.05) increase of hydroperoxide production, specifically at the highest concentration tested. Data obtained from the Comet assay indicated that cadmium chloride causes DNA damage in HepG₂ cells in a concentration-dependent manner. A strong concentration-response relationship (p < 0.05) was recorded between annexin V positive cells and cadmium chloride exposure. In summary, these in vitro studies provide clear evidence that cadmium chloride induces oxidative stress, DNA damage, and programmed cell death in human liver carcinoma (HepG₂) cells.

Cadmium Chloride Induces DNA Damage and Apoptosis of Human Liver Carcinoma Cells via Oxidative Stress

Cadmium is a heavy metal that has been shown to cause its toxicity in humans and animals. Many documented studies have shown that cadmium produces various genotoxic effects such as DNA damage and chromosomal aberrations. Ailments such as bone disease, renal damage, and several forms of cancer are attributed to overexposure to cadmium. Although there have been numerous studies examining the effects of cadmium in animal models and a few case studies involving communities where cadmium contamination has occurred, its molecular mechanisms of action are not fully elucidated. In this research, we hypothesized that oxidative stress plays a key role in cadmium chloride-induced toxicity, DNA damage, and apoptosis of human liver carcinoma (HepG₂) cells. To test our hypothesis, cell viability was determined by MTT assay. Lipid hydroperoxide content stress was estimated by lipid peroxidation assay. Genotoxic damage was tested by the means of alkaline single cell gel electrophoresis (Comet) assay. Cell apoptosis was measured by flow cytometry assessment (Annexin-V/PI assay). The result of MTT assay indicated that cadmium chloride induces toxicity to HepG₂ cells in a concentration-dependent manner, showing a 48 hr-LD50 of 3.6 µg/mL. Data generated from lipid peroxidation assay resulted in a significant (p < 0.05) increase of hydroperoxide production, specifically at the highest concentration tested. Data obtained from the Comet assay indicated that cadmium chloride causes DNA damage in HepG₂ cells in a concentration-dependent manner. A strong concentration-response relationship (p < 0.05) was recorded between annexin V positive cells and cadmium chloride exposure. In summary, these in vitro studies provide clear evidence that cadmium chloride induces oxidative stress, DNA damage, and programmed cell death in human liver carcinoma (HepG₂) cells.

DNA Damage, Cell Cycle Arrest, and Apoptosis Induction Caused by Lead in Human Leukemia Cells

In recent years, the industrial use of lead has been significantly reduced from paints and ceramic products, caulking, and pipe solder. Despite this progress, lead exposure continues to be a significant public health concern. The main goal of this research was to determine the in vitro mechanisms of lead nitrate [Pb(NO₃)₂] to induce DNA damage, apoptosis, and cell cycle arrest in human leukemia (HL-60) cells. To reach our goal, HL-60 cells were treated with different concentrations of Pb(NO₃)₂ for 24 h. Live cells and necrotic death cells were measured by the propidium idiode (PI) assay using the cellometer vision. Cell apoptosis was measured by the flow cytometry and DNA laddering. Cell cycle analysis was evaluated by the flow cytometry. The result of the PI demonstrated a significant (p < 0.05) increase of necrotic cell death in Pb(NO₃)₂-treated cells, indicative of membrane rupture by Pb(NO₃)₂ compared to the control. Data generated from the comet assay indicated a concentration-dependent increase in DNA damage, showing a significant increase (p < 0.05) in comet tail-length and percentages of DNA cleavage. Data generated from the flow cytometry assessment indicated that Pb(NO₃)₂ exposure significantly (p < 0.05) increased the proportion of caspase-3 positive cells (apoptotic cells) compared to the control. The flow cytometry assessment also indicated Pb(NO₃)₂ exposure caused cell cycle arrest at the G₀/G₁ checkpoint. The result of DNA laddering assay showed presence of DNA smear in the agarose gel with little presence of DNA fragments in the treated cells compared to the control. In summary, Pb(NO₃)₂ inhibits HL-60 cells proliferation by not only inducing DNA damage and cell cycle arrest at the G₀/G₁ checkpoint but also triggering the apoptosis through caspase-3 activation and nucleosomal DNA fragmentation accompanied by secondary necrosis. We believe that our study provides a new insight into the mechanisms of Pb(NO₃)₂ exposure and its associated adverse health effects.

Evaluation of Arsenic Trioxide Potential for Lung Cancer Treatment: Assessment of Apoptotic Mechanisms and Oxidative Damage

Background

Lung cancer is one of the most lethal and common cancers in the world, causing up to 3 million deaths annually. The chemotherapeutic drugs that have been used in treating lung cancer include cisplatin-pemetrexed, cisplastin-gencitabinoe, carboplatin-paclitaxel and crizotinib. Arsenic trioxide (ATO) has been used in the treatment of acute promyelocytic leukemia. However, its effects on lung cancer are not known. We hypothesize that ATO may also have a bioactivity against lung cancer, and its mechanisms of action may involve apoptosis, DNA damage and changes in stress-related proteins in lung cancer cells.

Methods

To test the above stated hypothesis, lung carcinoma (A549) cells were used as the test model. The effects of ATO were examined by performing 6-diamidine-2 phenylindole (DAPI) nuclear staining for morphological characterization of apoptosis, flow cytometry analysis for early apoptosis, and western blot analysis for stress-related proteins (Hsp70 and cfos) and apoptotic protein expressions. Also, the single cell gel electrophoresis (Comet) assay was used to evaluate the genotoxic effect.

Results

ATO-induced apoptosis was evidenced by chromatin condensation and formation of apoptotic bodies as revealed by DAPI nuclear staining. Cell shrinkage and membrane blebbing were observed at 4 and 6 µg/ml of ATO. Data from the western blot analysis revealed a significant dose-dependent increase (p < 0.05) in the Hsp 70, caspase 3 and p53 protein expression, and a significant (p < 0.05) decrease in the cfos, and bcl-2 protein expression at 4 and 6 µg/ml of ATO. There was a slight decrease in cytochrome c protein expression at 4 and 6 µg/ ml of ATO. Comet assay data revealed significant dose-dependent increases in the percentages of DNA damage, Comet tail lengths, and Comet tail moment.

Conclusion

Taken together our results indicate that ATO is cytotoxic to lung cancer cells and its bioactivity is associated with oxidative damage, changes in cellular morphology, and apoptosis.

Gallic acid decreases hepatitis C virus expression through its antioxidant capacity

Gallic acid (GA) is a natural phenolic compound that possesses various biological effects, including antioxidant, anti-inflammatory, antibiotic, anticancer, antiviral and cardiovascular protection activities. In addition, numerous studies have reported that antioxidants possess antiviral activities. Hepatitis C virus (HCV) is one of the most important causes of chronic liver diseases worldwide, but until recently, only a small number of antiviral agents had been developed against HCV. Therefore, the present study investigated whether GA exhibits an anti-HCV activity. The effects of GA on HCV expression were examined using a subgenomic HCV replicon cell culture system that expressed HCV nonstructural proteins (NSs). In addition, GA cytotoxicity was evaluated at concentrations between 100-600 mg/ml using an MTT assay. Huh-7 replicon cells were incubated with 300 mg/ml GA for different times, and the HCV-RNA and protein levels were measured by reverse transcription-quantitative polymerase chain reaction and western blot analysis, respectively. Pyrrolidine dithiocarbamate (PDTC) was used as an antioxidant control and reactive oxygen species (ROS) production was measured during the exposure. The results indicated that GA did not produce a statistically significant cytotoxicity in parental and HCV replicon cells. Furthermore, GA downregulated the expression levels of NS5A-HCV protein (~55%) and HCV-RNA (~50%) in a time-dependent manner compared with the levels in untreated cells. Notably, GA treatment decreased ROS production at the early time points of exposure in cells expressing HCV proteins. Similar results were obtained upon PDTC exposure. These findings suggest that the antioxidant capacity of GA may be involved in the downregulation of HCV replication in hepatoma cells.

Preclinical Assessment of Low Doses of Cisplatin in the Management of Acute Promyelocytic Leukemia

Cis-diamminedichloroplatinum (II) (cisplatin) is the most widely used chemotherapeutic drug for various cancers, but its effectiveness is limited by tumor cell resistance and the severe side effects it causes. Since high level of cisplatin is cytotoxic to both cancer and normal cells, the goal of the present study was to explore the effectiveness of prolonged low doses of cisplatin in the management of leukemia. To achieve our goal, human leukemia (HL-60) cells were treated with different doses (1, 2, or 3 µM) of cisplatin for 24, 48, 72 and 96 hours. Cell viability was assessed by MTS assay. Both oxidative stress damage and genotoxicity were estimated by antioxidants, lipid peroxidation, and comet assays, respectively. Data obtained from the MTS assay demonstrated that cisplatin treatment decreased the number of viable tumor cells by direct cell killing or by simply decreasing the rate of cellular proliferation in a dose- and time-dependent fashion. The results of the lipid peroxidation showed a significant increase (p<0.05) of malondialdehyde levels with increasing cisplatin doses. Results obtained from super oxide dismutase and catalase assays showed a gradual increase in antioxidant enzyme activity in cisplatin-treated cells compared to control cells. Data generated from the Comet assay demonstrated a significant dose-dependent increase in genotoxicity with respect to DNA damage as a result of cisplatin treatment. Taken together, our research demonstrated that cisplatin-induced cytotoxicity in HL-60 cells is mediated at least in part via induction of oxidative stress and oxidative damage.

β-ESTRADIOL INDUCES CYTOTOXIC EFFECTS TO HUMAN T-LYMPHOMA (JURKAT) CELLS THROUGH OXIDATIVE STRESS

β-estradiol is the most potent estrogen of a group of endogenous estrogen steroids which includes estrone and estriol. This steroid hormone is the most potent natural estrogen, produced mainly by the ovary, placenta, and in smaller amounts by the adrenal cortex, and the male testes. Although β-estradiol protects the renal and cardiovascular systems, the mechanisms involved remain unclear. In this research, we performed the MTT [3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay to evaluate the effect of β-estradiol on human T-lymphoma (Jurkat) cells upon 24 and 48 hours, respectively. Lipid peroxidation assay was also performed to estimate the levels of malondialdehyde (MDA) production in β-estradiol-treated cells. The results of MTT assay demonstrated that low, physiological levels of β-estradiol induce cellular proliferation in Jurkat T-cells. At higher dose of exposure, β-estradiol decreases the viability of Jurkat T-cells compared to the control cells. Data generated from lipid peroxidation assay resulted in a significant increase (p < 0.05) in MDA production in β-estradiol treated sample. Upon 48 h of exposure, MDA concentrations in the sample [µM] (mean ±SE, n = 3) compared to untreated control were 4.9 ± 1.7, 8.1 ± 1,6 11.5 ± 2.2, 21.1 ± 2.3, 19.5 ± 1.4, and 21.5 ± 2.6 in 0, 1, 2, 4, 8, and 16 µM β-estradiol, respectively. In summary, findings from this study demonstrated that high dose of β-estradiol is cytotoxic to Jurkat T-cells. This cytotoxicity is found to be associated with oxidative stress.

Downregulation of Sprouty homolog 2 by microRNA-21 inhibits proliferation, metastasis and invasion, however promotes the apoptosis of multiple myeloma cells

The aim of the present study was to assess the effects of sprouty homolog 2 (SPRY2) gene regulation by miR-21 on the occurrence, development and tumor metastasis in multiple myeloma (MM). The miR-21 expression lentiviral vector (LV)-anti-miR-21 and a liposome transfection method were used to screen MM cell lines with stable silent SPRY2. Real-time quantitative polymerase chain reaction (PCR) and western blot analyses were used to detect SPRY2 expression and miR-21 protein expression levels. An MTT assay was used to assess cell proliferation. Flow cytometry was used for analysis of cell cycle. A scratch test/wound healing assay was used to detect the cell migration ability. A Transwell assay was used to detect the cell invasion ability. Real-time quantitative PCR and western blot analysis showed that in the MM cell lines with high endogenous miR-21 expression (RPMI8226 and KM3), SPRY2 expression was significantly lower. Conversely, in the U266 cell line with low endogenous miR-21 expression, SPRY2 expression was significantly higher, and the gray values of miR-21 and SPRY2 protein in the respective cell lines showed statistically significant differences (P<0.01). Following transfection of U266 cells, the expression of miR-21 in the U266/LV-anti-miR21 lentiviral multiplicity of infection (MOI) 20 group and -MOI 40 group decreased significantly compared with that in the untransfected U266 group (P<0.05). SPRY2 protein expression in U266 cells transfected with miR-21 mimics was significantly reduced compared with that in the non-transfected (untreated) group and the negative control-transfected group (P<0.01). An MTT assay showed that compared with the non-transfected and negative control groups, the cell growth rate as well as the proliferation rate were significantly decreased in the transfection group 48, 72 and 96 h after transfection (P<0.01). Flow cytometric analysis showed that 48 and 72 h after transfection of U266 cells with miR-21 mimics, the apoptotic rates were (24.7±1.97 and 38.6±1.56%) in the U266 group, (27.3±1.72 and 37.3±1.59%) in the siRNA group and (12.7±1.27 and 22.1±1.63%) in the U266/miR-21 group. Compared with the two control groups, the apoptotic rate in the U266/miR-21 group was significantly decreased and the G₀/G₁ phase cell population was significantly reduced (P<0.05). Scratch experiments showed that the cell migration ability was significantly reduced in the transfection group 24 and 48 h after transfection (P<0.05). A Transwell invasion assay confirmed that the number of U266 cells which migrated through a Matrigel-covered polyphosphate membrane significantly decreased in the transfection group 24 and 48 h after transfection. The cell-penetrating ability was also significantly decreased (P<0.05). In conclusion, the downregulation of SPRY2 gene expression mediated by miR-21 promotes the proliferation and invasion of MM cells in vitro, suggesting that miR-21 may be a novel potential molecular therapeutic target in the treatment of MM.

Heavy metal toxicity and the environment

Heavy metals are naturally occurring elements that have a high atomic weight and a density at least five times greater than that of water. Their multiple industrial, domestic, agricultural, medical, and technological applications have led to their wide distribution in the environment, raising concerns over their potential effects on human health and the environment. Their toxicity depends on several factors including the dose, route of exposure, and chemical species, as well as the age, gender, genetics, and nutritional status of exposed individuals. Because of their high degree of toxicity, arsenic, cadmium, chromium, lead, and mercury rank among the priority metals that are of public health significance. These metallic elements are considered systemic toxicants that are known to induce multiple organ damage, even at lower levels of exposure. They are also classified as human carcinogens (known or probable) according to the US Environmental Protection Agency and the International Agency for Research on Cancer. This review provides an analysis of their environmental occurrence, production and use, potential for human exposure, and molecular mechanisms of toxicity, genotoxicity, and carcinogenicity.

ATP-binding cassette transporter A1 (ABCA1) promotes arsenic tolerance in human cells by reducing cellular arsenic accumulation

Arsenic is a toxic element widely distributed in nature, such as water and soil. To survive this metalloid in the environment, nearly all organisms develop strategies to tolerate arsenic toxicity to some degree. Some arsenic-resistance genes have been identified in bacteria and yeast, but for mammals, especially humans, these genes are largely unknown. The aim of the present study was to identify these genes and benefit our intervention of arsenic resistance. We first established a human arsenic-resistant ECV-304 (AsRE) cell line and then used suppression subtractive hybridization and microarray analysis to identify arsenic-resistant genes in these cells. Of the significantly upregulated genes, three ATP-binding cassette (ABC) subfamily members, namely ABCA1, ABCE1 and ABCF1, were chosen for further study with RNA interference and overexpression analyses. The 3-(4,5-dimethyl-2 thiazoyl)-2,5-diphenyl-2H-tetrazolium bromide assay was used to determine the cell survival rate and the IC50 , whereas atomic fluorescence spectrophotometry was used to determine intracellular arsenic levels. We found that among the three ABC genes, only when ABCA1 gene expression was silenced did cells obviously lose their arsenic tolerance. The arsenic accumulation in ABCA1 deficiency AsRE cells was greater than that in wild type AsRE cells. Overexpression of ABCA1 in HeLa cells decreased arsenic accumulation in the cells and the cells were more resistant to As(III) than control cells transfected with empty vector. These results suggest a new functional role for ABCA1 in the development of arsenic resistance in human cells.

Enhancement of arsenic trioxide-mediated changes in human induced pluripotent stem cells (IPS)

Induced pluripotent stem cells (IPS) are an artificially derived type of pluripotent stem cell, showing many of the same characteristics as natural pluripotent stem cells. IPS are a hopeful therapeutic model; however there is a critical need to determine their response to environmental toxins. Effects of arsenic on cells have been studied extensively; however, its effect on IPS is yet to be elucidated. Arsenic trioxide (ATO) has been shown to inhibit cell proliferation, induce apoptosis and genotoxicity in many cells. Based on ATOs action in other cells, we hypothesize that it will induce alterations in morphology, inhibit cell viability and induce a genotoxic effect on IPS. Cells were treated for 24 hours with ATO (0-9 µg/mL). Cell morphology, viability and DNA damage were documented. Results indicated sufficient changes in morphology of cell colonies mainly in cell ability to maintain grouping and ability to remain adherent. Cell viability decreased in a dose dependent manner. There were significant increases in tail length and moment as well as destruction of intact DNA as concentration increased. Exposure to ATO resulted in a reproducible dose dependent sequence of events marked by changes in morphology, decrease of cell viability, and induction of genotoxicity in IPS.

Arsenic trioxide induces oxidative stress, DNA damage, and mitochondrial pathway of apoptosis in human leukemia (HL-60) cells

Background

Acute promyelocytic leukemia (APL) is a subtype of acute myeloid leukemia (AML), which accounts for approximately 10% of all acute myloid leukemia cases. It is a blood cancer that is formed by chromosomal mutation. Each year in the United States, APL affects about 1,500 patients of all age groups and causes approximately 1.2% of cancer deaths. Arsenic trioxide (ATO) has been used successfully for treatment of APL patients, and both induction and consolidated therapy have resulted in complete remission. Recently published studies from our laboratory have demonstrated that ATO pharmacology as an anti-leukemic drug is associated with cytotoxic and genotoxic effects in leukemia cells.

Methods

In the present study, we further investigated the detailed molecular mechanism of ATO-mediated intrinsic pathway of apoptosis; using HL-60 cells as a test model. Oxidative stress was assessed by spectrophotometric measurements of MDA and GSH levels while genotoxicity was determined by single cell gel electrophoresis (Comet assay). Apoptosis pathway was analyzed by Western blot analysis of Bax, Bcl2 and caspase 3 expression, as well as immunocytochemistry and confocal imaging of Bax and Cyt c translocation and mitochondrial membrane potential depolarization.

Results

ATO significantly (p < 0.05) induces oxidative stress, DNA damage, and caspase 3 activityin HL-60 cells in a dose-dependent manner. It also activated the intrinsic pathway of apoptosis by significantly modulating (p < 0.05) the expression and translocation of apoptotic molecules and decreasing the mitochondrial membrane potential in leukemia cells.

Conclusion

Taken together, our research demonstrated that ATO induces mitochondrial pathway of apoptosis in HL-60 cells. This apoptotic signaling is modulated via oxidative stress, DNA damage, and change in mitochondrial membrane potential, translocation and upregulation of apoptotic proteins leading programmed cell death.

Genotoxic and epigenetic mechanisms in arsenic carcinogenicity

Arsenic is a human carcinogen with weak mutagenic properties that induces tumors through mechanisms not yet completely understood. People worldwide are exposed to arsenic-contaminated drinking water, and epidemiological studies showed a high percentage of lung, bladder, liver, and kidney cancer in these populations. Several mechanisms by which arsenical compounds induce tumorigenesis were proposed including genotoxic damage and chromosomal abnormalities. Over the past decade, a growing body of evidence indicated that epigenetic modifications have a role in arsenic-inducing adverse effects on human health. The main epigenetic mechanisms are DNA methylation in gene promoter regions that regulate gene expression, histone tail modifications that regulate the accessibility of transcriptional machinery to genes, and microRNA activity (noncoding RNA able to modulate mRNA translation). The "double capacity" of arsenic to induce mutations and epimutations could be the main cause of arsenic-induced carcinogenesis. The aim of this review is to better clarify the mechanisms of the initiation and/or the promotion of arsenic-induced carcinogenesis in order to understand the best way to perform an early diagnosis and a prompt prevention that is the key point for protecting arsenic-exposed population. Studies on arsenic-exposed population should be designed in order to examine more comprehensively the presence and consequences of these genetic/epigenetic alterations.

Vitamin D3 potentiates the antitumorigenic effects of arsenic trioxide in human leukemia (HL-60) cells

Background

Arsenic trioxide (ATO) is a novel form of therapy that has been found to aid acute promyelocytic leukemia (APL) patients. Our laboratory has demonstrated that ATO-induced cytotoxicity in human leukemia (HL-60) cells is mediated by oxidative stress. Pro-oxidants have been known to play a role in free radical-mediated oxidative stress. Vitamin D₃, (Vit D₃) an active metabolite of vitamin D has been reported to inhibit the growth of number neoplasms such as prostate, breast, colorectal, leukemia, and skin cancers. The goal of the present research was to use (HL-60) cells as an in vitro test model to evaluate whether low doses of Vit D₃ potentiate the toxicity of ATO and whether this toxic action is mediated via apoptotic mechanisms.

Method

HL-60 cells were treated either with a pharmacologic dose of ATO alone and with several low doses of Vit D₃. Cell survival was determined by MTT assay. Cell apoptosis was measured both by flow cytometry assessment, and DNA laddering assay.

Results

MTT assay indicated that Vit D₃ co-treatment potentiates ATO toxicity in HL-60 cells in a dose dependent manner. A statistically significant and dose-dependent increase (p <0.05) was recorded in annexin V positive cells (apoptotic cells) with increasing doses of Vit D₃ in ATO-treated cells. This finding was confirmed by the result of DNA laddering assay showing clear evidence of nucleosomal DNA fragmentation in vitamin and ATO co-treated cells.

Conclusion

The present study indicates that Vit D₃ potentiates the antitumor effects of ATO. This potentiation is mediated at least in part, through induction of phosphatidylserine externalization and nucleosomal DNA fragmentation. These findings highlight the potential impact of Vit D₃ in promoting the pharmacological effect of ATO, suggesting a possible future role of Vit D₃/ATO combination therapy in patients with acute promyelocytic leukemia (APL).

D-Glucose-Induced Cytotoxic, Genotoxic, and Apoptotic Effects on Human Breast Adenocarcinoma (MCF-7) Cells

Introduction

Glucose is a simple sugar that plays an important role in energy production in biological systems. However, it has been linked to many long-term health problems including the risk of heart disease and stroke, erectile dysfunction in men and pregnancy complications in women, and damage to the kidneys, nerves, eye and vision. Also, the underlying mechanisms of diabetic complications are poorly understood.

Methods

In the present study, D-glucose-induced cytotoxic, genotoxic, and apoptotic effects were studied using MCF-7 cells as an in vitro test model. Cell viability was determined by MTT assay. Genotoxic damage was tested by the means of alkaline single cell gel electrophoresis (Comet) assay. Cell apoptosis was measured by flow cytometry assessment (Annexin-V/PI assay).

Results

The results of MTT assay indicated that D-glucose significantly reduces the viability of MCF-7 cells in a dose and time-dependent manner. Similar trend was obtained with the trypan blue exclusion test. Data obtained from the Comet assay indicated that D-glucose causes DNA damage in MCF-7 cells in a dose-dependent manner. The flow cytometry assessment (Annexin V FITC/PI) showed a strong dose-response relationship between D-glucose exposure and annexin V positive MCF-7 cells undergoing early apoptosis.

Conclusion

Taking together, these data provide clear evidence that D-glucose induces cytotoxic, genotoxic, and apoptotic effects on MCF-7 cells. This finding represents the basis for further studies addressing the pathophysiological mechanisms of action of glucose overdose.

Combination treatment with platycodin D and osthole inhibits cell proliferation and invasion in mammary carcinoma cell lines

In this study, two invasive mammary carcinoma cells (MDA-MB-231 and 4T1) were utilized to evaluate the inhibitory activities of platycodin D, osthole, and the two in combination. The anti-proliferative effect was tested using the MTT and BrdU assay, and the combination of 15μM osthole and 75μM platycodin D was used for subsequent analyses. The anti-invasive effect was evaluated by the transwell assay. The results showed that the combination treatment reduced both cell proliferation and invasion. Western blot and real-time PCR revealed that the platycodin D-osthole combination significantly decreased TβRII, Smad2, Smad3 and Smad4 gene or protein expressions, as well as effectively blocked TGF-β-induced phosphorylation of Smad2 and Smad3. Thus, this study demonstrates that the anti-cancer effects of the platycodin D-osthole combination in breast cancer cells involve proliferation inhibition and invasion blockade, both of which may be mediated by perturbations in the TGF-β/Smads pathway.

Arsenic trioxide-mediated oxidative stress and genotoxicity in human hepatocellular carcinoma cells

BACKGROUND

Arsenic is a ubiquitous environmental toxicant, and abnormalities of the skin, lung, kidney, and liver are the most common outcomes of long-term arsenic exposure. This study was designed to investigate the possible mechanisms of genotoxicity induced by arsenic trioxide in human hepatocellular carcinoma cells.

METHODS AND RESULTS

A mild cytotoxic response of arsenic trioxide was observed in human hepatocellular carcinoma cells, as evident by (3-(4,5-dimethyl thiazol-2-yl)-2, 5-diphenyl tetrazolium bromide) and lactate dehydrogenase assays after 24 and 48 hours of exposure. Arsenic trioxide elicited a significant (P < 0.01) reduction in glutathione (15.67% and 26.52%), with a concomitant increase in malondialdehyde level (67.80% and 72.25%; P < 0.01), superoxide dismutase (76.42% and 81.09%; P < 0.01), catalase (73.33% and 76.47%; P < 0.01), and reactive oxygen species generation (44.04% and 56.14%; P < 0.01) after 24 and 48 hours of exposure, respectively. Statistically significant (P < 0.01) induction of DNA damage was observed by the comet assay in cells exposed to arsenic trioxide. It was also observed that apoptosis occurred through activation of caspase-3 and phosphatidylserine externalization in human hepatocellular carcinoma cells exposed to arsenic trioxide.

CONCLUSION

The results demonstrate that arsenic trioxide induces apoptosis and genotoxicity in human hepatocellular carcinoma cells through reactive oxygen species and oxidative stress.

Arsenic-induced biochemical and genotoxic effects and distribution in tissues of Sprague-Dawley rats

Arsenic (As) is a well documented human carcinogen. However, its mechanisms of toxic action and carcinogenic potential in animals have not been conclusive. In this research, we investigated the biochemical and genotoxic effects of As and studied its distribution in selected tissues of Sprague-Dawley rats. Four groups of six male rats, each weighing approximately 60 ± 2 g, were injected intraperitoneally, once a day for 5 days with doses of 5, 10, 15, 20 mg/kg bw of arsenic trioxide. A control group was also made of 6 animals injected with distilled water. Following anaesthetization, blood was collected and enzyme analysis was performed by spectrophotometry following standard protocols. At the end of experimentation, the animals were sacrificed, and the lung, liver, brain and kidney were collected 24 h after the fifth day treatment. Chromosome and micronuclei preparation was obtained from bone marrow cells. Arsenic exposure significantly increased (p<0.05) the activities of plasma alanine aminotransferase-glutamate pyruvate transaminase (ALT/GPT), and aspartate aminotransferase-glutamate oxaloacetate transaminase (AST/GOT), as well as the number of structural chromosomal aberrations (SCA) and frequency of micronuclei (MN) in the bone marrow cells. In contrast, the mitotic index in these cells was significantly reduced (p<0.05). These findings indicate that aminotransferases are candidate biomarkers for arsenic-induced hepatotoxicity. Our results also demonstrate that As has a strong genotoxic potential, as measured by the bone marrow SCA and MN tests in Sprague-Dawley rats. Total arsenic concentrations in tissues were measured by inductively coupled plasma mass spectrometry (ICP-MS). A dynamic reaction cell (DRC) with hydrogen gas was used to eliminate the ArCl interference at mass 75, in the measurement of total As. Total As doses in tissues tended to correlate with specific exposure levels.

Heavy metal toxicity and the environment

Heavy metals are naturally occurring elements that have a high atomic weight and a density at least five times greater than that of water. Their multiple industrial, domestic, agricultural, medical, and technological applications have led to their wide distribution in the environment, raising concerns over their potential effects on human health and the environment. Their toxicity depends on several factors including the dose, route of exposure, and chemical species, as well as the age, gender, genetics, and nutritional status of exposed individuals. Because of their high degree of toxicity, arsenic, cadmium, chromium, lead, and mercury rank among the priority metals that are of public health significance. These metallic elements are considered systemic toxicants that are known to induce multiple organ damage, even at lower levels of exposure. They are also classified as human carcinogens (known or probable) according to the US Environmental Protection Agency and the International Agency for Research on Cancer. This review provides an analysis of their environmental occurrence, production and use, potential for human exposure, and molecular mechanisms of toxicity, genotoxicity, and carcinogenicity.