CHARACTERIZATION OF THE HUMAN HEPATOCELLULAR CARCINOMA (HEPG2) CELL LINE AS AN IN VITRO MODEL FOR CADMIUM TOXICITY STUDIES

Evaluation of the Potential Cytoprotective Effect of Melatonin in Comparison with Vitamin E and Trolox against Cd2+-Induced Toxicity in SH-SY5Y, HCT 116, and HepG2 Cell Lines

Cadmium (Cd) toxicity poses a significant threat to cellular health, leading to oxidative stress and cell damage. Antioxidant agents, particularly those of natural origin, have been studied as a potential alternative for mitigating heavy metal toxicity. This study aimed to evaluate the cytoprotective effects of the antioxidant melatonin (MLT) in comparison with Vitamin E (VitE) and Trolox against Cd2+-induced cellular toxicity. The MTT assay was employed to assess cell viability in neuronal SH-SY5Y, colorectal HCT 116, and hepatic HepG2 cell lines. The results showed that all three antioxidants offered some level of protection against Cd toxicity, with Vitamin E proving to be the most effective. MLT also demonstrated a substantial cytoprotective effect, especially at the highest Cd concentration of 30 µM. These findings suggest that MLT, alongside Vit E and Trolox, could be valuable in mitigating the detrimental effects of Cd exposure by reducing the oxidative stress in these cellular models.

A systematic review of progress on hepatocellular carcinoma research over the past 30 years: a machine-learning-based bibliometric analysis

Introduction

Research on hepatocellular carcinoma (HCC) has grown significantly, and researchers cannot access the vast amount of literature. This study aimed to explore the research progress in studying HCC over the past 30 years using a machine learning-based bibliometric analysis and to suggest future research directions.

Methods

Comprehensive research was conducted between 1991 and 2020 in the public version of the PubMed database using the MeSH term "hepatocellular carcinoma." The complete records of the collected results were downloaded in Extensible Markup Language format, and the metadata of each publication, such as the publication year, the type of research, the corresponding author's country, the title, the abstract, and the MeSH terms, were analyzed. We adopted a latent Dirichlet allocation topic modeling method on the Python platform to analyze the research topics of the scientific publications.

Results

In the last 30 years, there has been significant and constant growth in the annual publications about HCC (annual percentage growth rate: 7.34%). Overall, 62,856 articles related to HCC from the past 30 years were searched and finally included in this study. Among the diagnosis-related terms, "Liver Cirrhosis" was the most studied. However, in the 2010s, "Biomarkers, Tumor" began to outpace "Liver Cirrhosis." Regarding the treatment-related MeSH terms, "Hepatectomy" was the most studied; however, recent studies related to "Antineoplastic Agents" showed a tendency to supersede hepatectomy. Regarding basic research, the study of "Cell Lines, Tumors,'' appeared after 2000 and has been the most studied among these terms.

Conclusion

This was the first machine learning-based bibliometric study to analyze more than 60,000 publications about HCC over the past 30 years. Despite significant efforts in analyzing the literature on basic research, its connection with the clinical field is still lacking. Therefore, more efforts are needed to convert and apply basic research results to clinical treatment. Additionally, it was found that microRNAs have potential as diagnostic and therapeutic targets for HCC.

Molecular Characterization of Thymus capitellatus Extracts and Their Antioxidant, Neuroprotective and Anti-Proliferative Activities

Thymus capitellatus Hoffmanns & Link is an endemic species of the Iberian Peninsula listed as near-threatened, due to its restricted geographical distribution, occurring mainly in Portugal's mainland. In this work, we detail for the first time T. capitellatus extracts' phytochemical composition, as well as an evaluation of bioactivities to point out potential health benefits. Aqueous decoction (AD) and hydroethanolic (HE) extracts were obtained, both rich in flavonoids. However, quercetin-(?)-O-hexoside was identified as the main compound in T. capitellatus HE extract, while the phenolic acid rosmarinic acid was the main component of AD extracts. In addition, HE extract presents significant amounts of salvianolic acids and of the terpenoids oleanolic and ursolic acid. Both extracts showed antioxidant activity, evaluated by their capacity to scavenge ABTS and superoxide radicals, as well as an ability to prevent lipid peroxidation. AD extracts were also effective in scavenging hydroxyl and nitric oxide radicals. As potential functional foods, T. capitellatus extracts presented neuroprotective and anti-diabetic activity, in addition to time- and dose-dependent anti-proliferative activity against Caco-2 (colorectal adenocarcinoma) and HepG2 (hepatic carcinoma) cells. HE extract presented higher cytotoxicity than AD extract, and HepG2 cells were more resistant than Caco-2 cells. After 24 h exposure to HE extract, the IC50 values were 330 μg/mL and 447 μg/mL for Caco-2 and HepG2 cells, respectively. T. capitellatus has potential as a functional food or as a source of bioactive molecules. These results also highlight the need to preserve species with as yet unknown molecular compositions and potential medicinal applications.

Zinc oxide/graphene oxide nanocomposites efficiently inhibited cadmium-induced hepatotoxicity via releasing Zn ions and up-regulating MRP1 expression

Environmental cadmium (Cd) pollution has been verified to associated with various hepatic diseases, as Cd has been classified as one of the TOP 20 Hazardous Substances and liver is the main target of Cd poisoning. However, to design efficient hepatic antidotes with excellent detoxification capacity and reveal their underlying mechanism(s) are still challenges in Cd detoxification. Herein, ZnO/GO nanocomposites with favorable biocompatibility was uncovered their advanced function against Cd-elicited liver damage at the in situ level in vivo by 9.4 T magnetic resonance imaging (MRI). To explore the cellular detoxification mechanism, ZnO/GO nanocomposites was found to effectively inhibit the cyto- and geno-toxicity of Cd with the maximum antagonistic efficiency to be approximately 90%. Mechanistically, ZnO/GO nanocomposites competitively inhibited the cellular Cd uptake through releasing Zn ions, and significantly promoted Cd excretion via targeting the efflux pump of multidrug resistance associated protein1 (MRP1), which was confirmed by mass spectra and immunohistochemical analysis in kidney, a main excretion organ of Cd. Our data provided a novel approach against Cd-elicited hepatotoxic responses by constructed ZnO/GO nanocomposites both in vitro and in vivo, which may have promising application in prevention and detoxification for Cd poisoning.

Are In Vitro Cytotoxicity Assessments of Environmental Samples Useful for Characterizing the Risk of Exposure to Multiple Contaminants at the Workplace? A Systematic Review

In some occupational environments risk characterization is challenging or impossible to achieve due to the presence of multiple pollutants and contaminants. Thus, in vitro testing using the most relevant cell lines will provide information concerning health effects due to the co-exposure to multiple stressors. The aim of this review article is to identify studies where the cytotoxicity assessment was performed in environmental samples, as well as to describe the main outputs and challenges regarding risk characterization and management. This study is based on a study of the available information/data on cytotoxicity assessment performed on environmental samples following the PRISMA methodology. Different cell lines were used depending on the environment assessed and exposure routes implicated. The A549 alveolar epithelial cell line was applied in four studies for occupational exposure in the waste sorting industry and for outdoor environments; lymphocytes were used in two studies for occupational and outdoor environments; swine kidney cells were used in three studies performed in the waste industry and hepatocellular/Hep G2 in one study in the waste industry. Cytotoxicity assessments in environmental samples should have a more prominent role due to their contribution for identifying and better understanding the associations between co-exposure to environmental contaminants and adverse human health effects as a prioritization for risk management.

Determination of Perflourooctanoic Acid Toxicity in a Human Hepatocarcinoma Cell Line

BACKGROUND

Perfluorooctanoic acid (PFOA) is used in different industrial and commercial products. Research shows the presence of PFOA in home dusts, tap and surface water, and in biological samples. The International Agency for Research on Cancer (IARC) has classified PFOA as a possible carcinogen for humans. The liver is thought to be a target organ of PFOA accumulation and toxicity.

OBJECTIVE

Some studies have found toxic effects on the liver and related mechanisms; however, more studies are needed to better understand PFOA - induced hepatotoxicity.

METHODS

In the present study, a human hepatocarcinoma cell line was exposed to PFOA for 24 hours and cell viability, apoptosis, the oxidative system and immune response were evaluated.

RESULTS

While apoptosis was the main cell death pathway at low concentration (86.5%), the necrotic cell fraction increased with higher concentrations (46.7%). Significant changes in the reactive oxygen species (5.3-folds) glutathione (GSH) (1.7-folds) and catalase (CAT) (1.4-folds) levels were observed, as well as changes to interleukin-6 (≤1.8-fold) and interleukin-8 levels (35-40%).

CONCLUSIONS

In light of the data, PFOA is potentially hepatotoxic through the investigated pathways. The results represent a background for future in vivo mechanistic studies.

COMPETING INTERESTS

The authors declare no competing financial interests.

Urea-functionalized organoselenium compounds as promising anti-HepG2 and apoptosis-inducing agents

Hepatocellular carcinoma is a highly aggressive and difficult-to-treat type of cancer. Incorporating urea functionality into the backbone of organoselenium compounds is expected to develop promising chemotherapeutic leads against liver cancer. Methods: Urea-functionalized organoselenium compounds were synthesized in good yields, and their cytotoxicity was evaluated against HepG2 cells. Results: 1,1'-(Diselanediylbis(4,1-phenylene))bis(3-phenylurea) (14) exhibited efficient anti-HepG2 activity in sub-micromolar concentrations, with no toxicity to normal human skin fibroblasts. The molecular mechanisms of the diselenide-based urea 14 were evaluated using colony formation, wound healing, 3D spheroid invasion assays, cell cycle analysis and apoptosis induction. Its redox properties were also assessed by using different bioassays. Conclusion: Our study revealed promising anticancer, antimigratory and anti-invasiveness properties of 1,1'-(diselanediylbis(4,1-phenylene))bis(3-phenylurea) (14) against HepG2.

Underlying mechanisms of cytotoxicity in HepG2 hepatocarcinoma cells exposed to arsenic, cadmium and mercury individually and in combination

BACKGROUND

Toxicity data regarding combinational exposure of humans to arsenic, cadmium and mercury is scarce. Although hepatotoxicity has been reported, limited information is available on their mechanistic underpinnings. The cytotoxic mechanisms of these metals were determined in HepG2 hepatocarcinoma cell lines after individual and combinational exposure.

METHODS

HepG2 cells were exposed to heavy metals (sodium arsenite, cadmium chloride, and mercury chloride) individually or in combination for 24 h, after which cell density, mitochondrial membrane potential (ΔΨm), reactive oxygen species (ROS), reduced glutathione (GSH), adenosine triphosphate (ATP) and caspase-3/7 activity was assessed.

RESULTS AND DISCUSSION

Cadmium (IC₅₀ = 0.43 mg/L) and the combination (0.45 mg/L, arsenic reference) were most cytotoxic, followed by arsenic (6.71 mg/L) and mercury (28.23 mg/L). Depolarisation of the ΔΨm and reductions in ROS, GSH and ATP levels occurred. Arsenic, cadmium and the combination increased caspase-3/7 activity, while mercury reduced it.

CONCLUSION

The combination produced a greater, albeit mechanistically similar, cytotoxicity compared to individual metals. Cytotoxicity was dependent on altered mitochondrial integrity, redox-status, and bioenergetics. Although the combination's cytotoxicity was associated with caspase-3/7 activity, this was not true for mercury. Heavy metal interactions should be assessed to elucidate molecular underpinnings of cytotoxicity.

Genotoxicity response of Vicia faba seedlings to cadmium in soils as characterized by direct soil exposure and micronucleus test

To overcome the drawbacks of the Vicia faba root tip micronucleus test in soil using the solution extract method, we conducted a potting experiment by direct soil exposure. Cadmium was spiked into 3 typical soils (brown soil, red soil, and black soil) to simulate environmental concentrations (0.625, 1.25, 2.5, 5, and 10 mg kg^-1). Multiple Vicia faba tissues (primary root tips, secondary root tips, and leaf tips) were sampled, and mitotic index (MI), chromosome aberration frequency (CA), and micronucleus frequency (MN) were used as endpoints after a seedling period of 5 days. The results showed a response between Cd concentrations and multiple sampling tissues of Vicia faba, and the secondary root tips responded to Cd stress the most, followed by primary root tips and leaf tips. Soil physicochemical properties (e.g., pH, total phosphorus, total organic carbon, etc.) influenced the genotoxicity of Cd, and pH was the dominant factor, which resulted in the genetic toxicity response of Cd in soils in the order: red soil > brown soil > black soil. The lowest observable effect concentration (LOEC) of Cd was 1.25 mg kg^-1 for both brown soil and red soil and 2.5 mg kg^-1 for black soil. In view of this, we suggested that soil properties should be considered in evaluating genotoxicity risk of Cd in soil, especially with soil pH range, and the secondary root tips should be taken as suitable test tissues in the MN test due to its more sensible response feature to Cd stress in soil.

Ginkgo biloba L. Leaf Extract Protects HepG2 Cells Against Paraquat-Induced Oxidative DNA Damage

Ginkgo biloba L. leaf extracts and herbal infusions are used worldwide due to the health benefits that are attributed to its use, including anti-neoplastic, anti-aging, neuro-protection, antioxidant and others. The aim of this study was to evaluate the effect of an aqueous Ginkgo biloba extract on HepG2 cell viability, genotoxicity and DNA protection against paraquat-induced oxidative damage. Exposure to paraquat (PQ), over 24 h incubation at 1.0 and 1.5 µM, did not significantly reduce cell viability but induced concentration and time-dependent oxidative DNA damage. Ginkgo biloba leaf extract produced dose-dependent cytotoxicity (IC₅₀ = 540.8 ± 40.5 µg/mL at 24 h exposure), and short incubations (1 h) produced basal and oxidative DNA damage (>750 and 1500 µg/mL, respectively). However, lower concentrations (e.g., 75 µg/mL) of Ginkgo biloba leaf extract were not cytotoxic and reduced basal DNA damage, indicating a protective effect at incubations up to 4 h. On the other hand, longer incubations (24 h) induced oxidative DNA damage. Co-incubation of HepG2 cells for 4 h, with G. biloba leaf extract (75 µg/mL) and PQ (1.0 or 1.5 µM) significantly reduced PQ-induced oxidative DNA damage. In conclusion, the consumption of Ginkgo biloba leaf extract for long periods at high doses/concentrations is potentially toxic; however, low doses protect the cells against basal oxidative damage and against environmentally derived toxicants that induce oxidative DNA damage.

In vitro Models and On-Chip Systems: Biomaterial Interaction Studies With Tissues Generated Using Lung Epithelial and Liver Metabolic Cell Lines

In vitro models are very important in medicine and biology, because they provide an insight into cells' and microorganisms' behavior. Since these cells and microorganisms are isolated from their natural environment, these models may not completely or precisely predict the effects on the entire organism. Improvement in this area is secured by organ-on-a-chip development. The organ-on-a-chip assumes cells cultured in a microfluidic chip. The chip simulates bioactivities, mechanics and physiological behavior of organs or organ systems, generating artificial organs in that way. There are several cell lines used so far for each tested artificial organ. For lungs, mostly used cell lines are 16HBE, A549, Calu-3, NHBE, while mostly used cell lines for liver are HepG2, Hep 3B, TPH1, etc. In this paper, state of the art for lung and liver organ-on-a-chip is presented, together with the established in vitro testing on lung and liver cell lines, with the emphasis on Calu-3 (for lung cell lines) and Hep-G2 (for liver cell lines). Primary focus in this review is to discuss different researches on the topics of lung and liver cell line models, approaches in determining fate and transport, cell partitioning, cell growth and division, as well as cell dynamics, meaning toxicity and effects. The review is finalized with current research gaps and problems, stating potential future developments in the field.

Gender Differences in the Hepatotoxicity and Toxicokinetics of Emodin: The Potential Mechanisms Mediated by UGT2B7 and MRP2

Emodin is a main anthraquinone compound which exists in Chinese traditional medicines including Polygonum multiflorum and Rhubarb. It is documented to have obvious liver and kidney toxicity. This study aims to (a) estimate gender differences of the hepatotoxicity and toxicokinetics in rats after oral administration of emodin (60 and 150 mg/kg/d) for a consecutive 28 days and (b) clarify relative mechanisms caused by glucuronidation and disposition. Hepatotoxicity was significantly higher in female rats than that in male rats, as evidenced by histopathological and biochemical tests. Similarly, the toxicokinetic profiles of emodin have time and gender differences, which could cause time and gender differences in hepatotoxicity. The metabolic and transcriptomics data of 55 human liver and 36 human kidney samples demonstrated that UDP-glucuronosyltransferase 2B7 (UGT2B7) was the predominant enzyme for emodin glucuronidation. A genome-wide association study (GWAS) identified that rs11726899 located within ∼50 kb of the transcript of UGT2B could significantly affect emodin metabolism. Knockdown of UGT2B7 in HepG2 cells significantly decreased emodin glucuronidation and increased cytotoxicity of emodin. The gene expression and protein levels of UGT2B7 were decreased, but those of the multidrug-resistant-protein 2 (MRP2) were increased in HepG2 cells after being treated with 50 μM emodin for 48 h. Long-term use of emodin could decrease the intrinsic clearance (CL_int, decreased by 18.5%-35.4%) values of zidovidue (UGT2B7 substrate) glucuronide in both male and female liver microsomes from rats administrated with emodin for 28 days, thus causing the accumulation of emodin. However, higher self-induced MRP2 expression and lower hepatotoxicity were observed in emodin-treated male rats compared to that in female rats. Therefore, gender differences in the hepatotoxicity and toxicokinetics of emodin are potentially mediated by the coupling of UGT2B7 and MRP2 in vivo.

Impaired Cell Viability and Functionality of Hepatocytes After Incubation With Septic Plasma-Results of a Second Prospective Biosensor Study

Liver dysfunction (LD) and liver failure are associated with poor outcome in critically ill patients. In patients with severe sepsis or septic shock, LD occurred in nearly 19% of patients. An early diagnosis of LD at time of initial damage of the liver can lead to a better prognosis of these patients because an early start of therapy is possible. We performed a second prospective study with septic patients to test a new cell-based cytotoxicity device (biosensor) to evaluate clinical relevance for early diagnosis of LD and prognostic capacity. In the clinical study, 99 intensive care unit patients were included in two groups. From the patients of the septic group (n = 51, SG), and the control (non-septic) group [n = 49, control group (CG)] were drawn 20 ml blood at inclusion, after 3, and 7 days for testing with the biosensor. Patients’ data were recorded for hospital survival, organ function, and demographic data, illness severity [acute physiology and chronic health evaluation (APACHE) II-, sepsis-related organ failure assessment (SOFA) scores], cytokines, circulating-free deoxyribonucleic acid/neutrophil-derived extracellular traps (cf-DNA/NETs), microbiological results, and pre-morbidity. For the developed cytotoxicity test, the human liver cell line HepG2/C3A was used. Patients’ plasma was incubated in a microtiter plate assay with the test cells and after 6 days incubation the viability (trypan blue staining, XTT-test) and functionality (synthesis of albumin, cytochrome 1A2 activity) was analyzed. An impairment of viability and functionality of test cells was only seen in the SG compared with the CG. The plasma of non-survivors in the SG led to a more pronounced impairment of test cells than the plasma of survivors at inclusion. In addition, the levels of cf-DNA/NETs were significantly higher in the SG at inclusion, after 3, and after 7 days compared with the CG. The SG showed an in-hospital mortality of 24% and the values of bilirubin, APACHE II-, and SOFA scores were markedly higher at inclusion than in the CG. Hepatotoxicity of septic plasma was already detected with the liver cell-based biosensor at inclusion and also in the course of disease. The biosensor may be a tool for early diagnosis of LD in septic patients and may have prognostic relevance.

Anticancer activity study of A3 adenosine receptor agonists

AIMS

A₃ adenosine receptor (A₃AR) signalling activation seems to mediate anticancer effect, and it has been targeted for drug development. The identification of potent and selective A₃AR agonists could be crucial for cancer drug development.

MATERIALS AND METHODS

In the present study was determined the in vitro activity of known 1-3 and newly 4-6 synthesized compounds with high A₃AR affinity and selectivity (K_i in the low nanomolar range) in binding studies. Effect of known and novel A₃AR agonists on human prostate cancer (PC3), hepatocellular carcinoma (Hep G2), and epithelial colorectal carcinoma (Caco-2) cells were analysed by cytotoxicity assay, dose and time dependent inhibitor assay, migration, apoptosis, autophagy and reactive oxygen species (ROS) assays.

KEY FINDINGS

Results show that the anticancer effect is not due to A₃AR activation alone. In fact, the more active and selective agonist versus A₃AR, compound 1, results inactive on cancer cells such as compounds 2-4. Moreover, results show that the novel compound 5, at micromolar concentration range (IC₅₀ = 28.0 μM), inhibits the growth of PC3, Hep G2, and Caco-2 cells and their migration in time- and dose- dependent manner. The mechanism involved in cell death is attributable to apoptosis. At the same time compound 5 promotes autophagy, which induce apoptosis producing autophagic cell death. Further investigation revealed that compound 5 elevates the level of ROS in all cancer cells tested, suggesting the involvement of ROS in cell death.

SIGNIFICANCE

These results show that the new compound 5 exerts inhibitory effect on cancer cells through differential effect and may serve as a potential anticancer agent.

Analysis of molecular mechanisms of 5-fluorouracil-induced steatosis and inflammation in vitro and in mice

Chemotherapy-associated steatohepatitis is attracting increasing attention because it heralds an increased risk of morbidity and mortality in patients undergoing surgery because of liver metastases. The aim of this study was to develop in vitro and in vivo models to analyze the pathogenesis of 5-fluorouracil (5-FU)-induced steatohepatitis.

Therefore, primary human hepatocytes and HepG2 hepatoma cells were incubated with 5-FU at non-toxic concentrations up to 24 h. Furthermore, hepatic tissue of C57BL/6N mice was analyzed 24 h after application of a single 5-FU dose (200 mg/kg body weight). In vitro, incubation with 5-FU induced a significant increase of hepatocellular triglyceride levels. This was paralleled by an impairment of mitochondrial function and a dose- and time-dependently increased expression of fatty acid acyl-CoA oxidase 1 (ACOX1), which catalyzes the initial step for peroxisomal β-oxidation. The latter is known to generate reactive oxygen species, and consequently, expression of the antioxidant enzyme heme oxygenase 1 (HMOX1) was significantly upregulated in 5-FU-treated cells, indicative for oxidative stress. Furthermore, 5-FU significantly induced c-Jun N-terminal kinase (JNK) activation and the expression of pro-inflammatory genes IL-8 and ICAM-1. Also in vivo, 5-FU significantly induced hepatic ACOX1 and HMOX1 expression as well as JNK-activation, pro-inflammatory gene expression and immune cell infiltration. In summary, we identified molecular mechanisms by which 5-FU induces hepatocellular lipid accumulation and inflammation. Our newly developed models can be used to gain further insight into the pathogenesis of 5-FU-induced steatohepatitis and to develop therapeutic strategies to inhibit its development and progression.

Rocuronium is more hepatotoxic than succinylcholine in vitro

BACKGROUND

The development of liver failure is a major problem in critically ill patients. The hepatotoxicity of many drugs, as one important reason for liver failure, is poorly screened for in human models. Rocuronium and succinylcholine are neuromuscular blocking agents used for tracheal intubation and for rapid-sequence induction.

OBJECTIVE

We used an in-vitro test with a permanent cell line and compared rocuronium and succinylcholine for hepatotoxicity.

DESIGN

In-vitro study.

SETTING

A basic science laboratory, University Hospital Rostock, Germany.

MATERIAL/(PATIENTS)

The basic test compound is the permanent human liver cell line HepG2/C3A. In a standardised microtitre plate assay the toxicity of different concentrations of rocuronium, succinylcholine and plasma control was tested.

INTERVENTIONS

After two incubation periods of 3 days, the viability of cells (XTT test, lactate dehydrogenase release and trypan blue staining), micro-albumin synthesis and the cytochrome 1A2 activity (metabolism of ethoxyresorufin) were measured.

MAIN OUTCOME MEASURES

Differences between rocuronium and succinylcholine were assessed using the Kruskal-Wallis one-way test and two-tailed Mann-Whitney U test.

RESULTS

Rocuronium, but not succinylcholine, led to a significant dose-dependent decrease of viability, albumin synthesis and cytochrome 1A2 activity of test cells.

CONCLUSION

An in-vitro test with a cell line showed hepatotoxicity of rocuronium that was dose-dependent. Further studies are needed to investigate the underlying mechanisms of the effects of rocuronium on hepatic cellular integrity.

TRIAL REGISTRATION

Not suitable.

Epilobium angustifolium L.: A medicinal plant with therapeutic properties

Epilobium angustifolium L. is a medicinal plant belonging to the Onagraceae family, which includes more than 200 different species from all over the world. Traditional medicinal applications include treatment of prostate, gastrointestinal, menstrual disorders and recently it has been used for its analgesic and anti-inflammatory activity. In this investigation E. angustifolium was collected in Ternopil region of Ukraine. The obtained data demonstrated that E. angustifolium herb extract, rich in polyphenolic compounds such as flavonoids and tannins, display high antioxidant properties. In addition the potential anticancer activity has been investigated in vitro on human hepatocellular carcinoma cells (HepG2). Furthermore the cytotoxic and genotoxic effects of E. angustifolium have been investigated respectively by MTT and Comet assay. Results showed that at low concentration, up to 25 μg/mL, the cytotoxic effect was not observed. Increasing concentration from 50 to 75 μg/mL reduced significantly cell viability and induced an important DNA damage in hepatocellular carcinoma. These promising data were also confirmed with mitochondrial potential test. It is possible to conclude that E. angustifolium has beneficial properties in low concentration, in term of antioxidant activity, and it could be a potential antitumoral natural product if it will be used at high concentration

Impact of Environmental Pollutant Cadmium on the Establishment of a Cancer Stem Cell Population in Breast and Hepatic Cancer

Cadmium, a heavy metal pollutant, causes cancer. The existence of cancer stem cells (CSCs) in tumors is widely considered to be the reason for the recurrence and treatment failure of cancer. Increasing evidence has confirmed that under certain conditions non-CSCs could be converted into CSCs. The impact of cadmium on the development of CSC lineage in the bulk tumor cell population is not yet studied. The aim of this study was to evaluate the effect of cadmium on the conversion of non-CSCs to CSCs and the identification of CSCs based on the concurrent monitoring of multiple CSC markers. High-content monitoring of molecular markers was performed using quantum dot (QD) nanoprobes and an acousto-optical tunable filter (AOTF)-based imaging device. Cadmium treatment significantly increased the CSC population in MCF-7 and HepG2 cell lines. The cadmium-induced CSCs were identified by a concurrent analysis of stem-cell markers, namely, CD44, CD24, CD133, and ALDH1. Moreover, increased m-RNA expression of CD44, ALDH1, and CD133 and protein expression of p-Ras, p-Raf-1, p-MEK-1, and p-ERK-1 were observed in the cadmium-treated MCF-7 and HepG2 cells. This study demonstrates that cadmium induces the gene expression of CSC markers in the breast and liver cancer cell lineage and promotes the conversion of non-CSCs to CSCs.

New insights into cytotoxicity induced by microcystin-LR, estradiol, and ractopamine with mathematical models: Individual and combined effects

Humans are most likely to be exposed to microcystins (MCs) combined with other water pollutants rather than to individual compounds through the consumption of contaminated drinking water or through recreational activities, such as swimming. However, the combined effects of MC-LR, estradiol (EST), and ractopamine (RAC) have not been extensively researched. The goal of this study was to investigate the combined effects of these compounds. For this purpose, cytotoxicity was evaluated in HepG2 cells treated with single or combined doses of MC-LR, EST, and RAC based on concentration addition (CA), independent action (IA), and Chou-Talalay's combination-index (CI) methods. Singly applied MC-LR and EST induced HepG2 cellular proliferation at low-concentration levels (1 × 10^-12-1 × 10^-9 M), and decreased viability at higher doses of exposure (1 × 10^-9-1 × 10^-6 M). Exposure to binary or ternary mixtures of MC-LR, EST, and RAC exhibited synergistic effects at high concentrations, irrespective of the models used. In contrast, antagonism was observed for the mixture of MC-LR and EST at relatively low concentrations. A synergistic effect on reactive oxygen species (ROS) generation was observed for the combined drugs at high concentrations. Additionally, the ratio of apoptotic cells was increased more by the combined drugs than the single drugs, consistent with the inhibition of cell viability. The ROS increase after treatment with the combined drugs may enhance cytotoxicity and subsequently lead to cell apoptosis. Given the interactions between MC-LR, EST, and RAC, government regulatory standards for MC-LR should consider the toxicological interactions between MC-LR and other environment pollutions.

Procalcitonin Impairs Liver Cell Viability and Function In Vitro: A Potential New Mechanism of Liver Dysfunction and Failure during Sepsis?

Purpose. Liver dysfunction and failure are severe complications of sepsis and result in poor outcome and increased mortality. The underlying pathologic mechanisms of hepatocyte dysfunction and necrosis during sepsis are only incompletely understood. Here, we investigated whether procalcitonin, a biomarker of sepsis, modulates liver cell function and viability. Materials and Methods. Employing a previously characterized and patented biosensor system evaluating hepatocyte toxicity in vitro, human hepatocellular carcinoma cells (HepG2/C3A) were exposed to 0.01-50 ng/mL procalcitonin for 2 × 72 h and evaluated for proliferation, necrosis, metabolic activity, cellular integrity, microalbumin synthesis, and detoxification capacity. Acetaminophen served as positive control. For further standardization, procalcitonin effects were confirmed in a cellular toxicology assay panel employing L929 fibroblasts. Data were analyzed using ANOVA/Tukey's test. Results. Already at concentrations as low as 0.25 ng/mL, procalcitonin induced HepG2/C3A necrosis (P < 0.05) and reduced metabolic activity, cellular integrity, synthesis, and detoxification capacity (all P < 0.001). Comparable effects were obtained employing L929 fibroblasts. Conclusion. We provide evidence for procalcitonin to directly impair function and viability of human hepatocytes and exert general cytotoxicity in vitro. Therapeutical targeting of procalcitonin could thus display a novel approach to reduce incidence of liver dysfunction and failure during sepsis and lower morbidity and mortality of septic patients.

In Vitro Protective Effects of Lycium barbarum Berries Cultivated in Umbria (Italy) on Human Hepatocellular Carcinoma Cells

Lycium barbarum is a famous plant in the traditional Chinese medicine. The plant is known to have health-promoting bioactive components. The properties of Lycium barbarum berries cultivated in Umbria (Italy) and their effect on human hepatocellular carcinoma cells (HepG2) have been investigated in this work. The obtained results demonstrated that the Lycium barbarum berries from Umbria region display high antioxidant properties evaluated by total phenolic content and ORAC method, on hydrophilic and lipophilic fractions. Moreover, on HepG2 cell line Lycium barbarum berries extract did not change cell viability analyzed by MTT and Trypan blue exclusion assay and did not induce genotoxic effect analyzed by comet assay. Furthermore, it was demonstrated, for the first time, that the berries extract showed a protective effect on DNA damage, expressed as antigenotoxic activity in vitro. Finally, Lycium barbarum berries extract was able to modulate the expression of genes involved in oxidative stress, proliferation, apoptosis, and cancer. In particular, downexpression of genes involved in tumor migration and invasion (CCL5), in increased risk of metastasis and antiapoptotic signal (DUSP1), and in carcinogenesis (GPx-3 and PTGS1), together with overexpression of tumor suppressor gene (MT3), suggested that Umbrian Lycium barbarum berries could play a protective role against hepatocellular carcinoma.

Encapsulation of Cardamom Essential Oil in Chitosan Nano-composites: In-vitro Efficacy on Antibiotic-Resistant Bacterial Pathogens and Cytotoxicity Studies

Natural antimicrobial agents, particularly essential oils present an excellent alternative to current antibiotics due to their potent and broad-spectrum antimicrobial potential, unique mechanisms of action and low tendency to induce resistance. However their potential as a viable therapeutic alternative is greatly compromised due to their hydrophobic and volatile nature. The objective of the current research was to explore the anti-pathogenic potential of essential oils in a bio-based nano-carrier system. Six different essential oils were tested on multidrug-resistant bacterial pathogens. However, cardamom oil was selected for nano-encapsulation because of most potent anti-microbial activity. Cardamom oil loaded chitosan nano-particles were prepared by ionic gelation method with an encapsulation efficiency of more than 90% and size was estimated to be 50–100 nm. The Zeta potential was more than +50 mV that indicate a stable nano-dispersion. Cytotoxicity analysis indicated non haemolytic and non-cytotoxic behaviour on human corneal epithelial cells and HepG2 cell lines. Cardamom oil loaded chitosan nano-particles were found to exhibit excellent anti-microbial potential against extended spectrum β lactamase producing Escherichia coli and methicillin resistant Staphylococcus aureus. Our results suggested safety and efficacy of cardamom oil loaded chitosan nano-particles for treating multidrug-resistant pathogens hence offer an effective alternative to current antibiotic therapy.

Genotoxic potential of selected cytostatic drugs in human and zebrafish cells

Due to their increasing use, the residues of anti-neoplastic drugs have become emerging pollutants in aquatic environments. Most of them directly or indirectly interfere with the cell's genome, which classifies them into a group of particularly dangerous compounds. The aim of the present study was to conduct a comparative in vitro toxicological characterisation of three commonly used cytostatics with different mechanisms of action (5-fluorouracil [5-FU], cisplatin [CDDP] and etoposide [ET]) towards zebrafish liver (ZFL) cell line, human hepatoma (HepG2) cells and human peripheral blood lymphocytes (HPBLs). Cytotoxicity was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and acridine orange/ethidium bromide staining. All three drugs induced time- and dose-dependent decreases in cell viability. The sensitivity of ZFL and HepG2 cells towards the cytotoxicity of 5-FU was comparable (half maximal inhibitory concentration (IC50) 5.3 to 10.4 μg/mL). ZFL cells were more sensitive towards ET- (IC50 0.4 μg/mL) and HepG2 towards CDDP- (IC50 1.4 μg/mL) induced cytotoxicity. Genotoxicity was determined by comet assay and cytokinesis block micronucleus (CBMN) assay. ZFL cells were the most sensitive, and HPBLs were the least sensitive. In ZFL cells, induction of DNA strand breaks was a more sensitive genotoxicity endpoint than micronuclei (MNi) induction; the lowest effective concentration (LOEC) for DNA strand break induction was 0.001 μg/mL for ET, 0.01 μg/mL for 5-FU and 0.1 μg/mL for CDDP. In HepG2 cells, MNi induction was a more sensitive genotoxicity endpoint. The LOEC values were 0.01 μg/mL for ET, 0.1 μg/mL for 5-FU and 1 μg/mL for CDDP. The higher sensitivity of ZFL cells to cytostatic drugs raises the question of the impact of such compounds in aquatic ecosystem. Since little is known on the effect of such drugs on aquatic organisms, our results demonstrate that ZFL cells provide a relevant and sensitive tool to screen genotoxic potential of environmental pollutant in the frame of hazard assessment.

The stress response of human proximal tubule cells to cadmium involves up-regulation of haemoxygenase 1 and metallothionein but not cytochrome P450 enzymes

Enzymes of the cytochrome P450 (CYP) super-family are implicated in cadmium (Cd) -induced nephrotoxicity, however, direct evidence is lacking. This study investigated the endogenous expression of various CYP proteins together with the stress-response proteins, heme oxygenase-1 (HO-1) and metallothionein (MT) in human kidney sections and in cadmium-exposed primary cultures of human proximal tubular epithelial cells (PTC). By immunohistochemistry, the CYP members 2B6, 4A11 and 4F2 were prominently expressed in the cortical proximal tubular cells and to a lesser extent in distal tubular cells. Low levels of CYPs 2E1 and 3A4 were also detected. In PTC, in the absence of Cd, CYP2E1, CYP3A4, CYP4F2 and MT were expressed, but HO-1, CYP2B6 and CYP4A11 were not detected. A range of cadmium concentrations (0-100μM) were utilized to induce stress conditions. MT protein was further induced by as little as 0.5μM cadmium, reaching a 6-fold induction at 20μM, whereas for HO-1, a 5μM cadmium concentration was required for initial induction and at 20μM cadmium reached a 15-fold induction. The expression of CYP2E1, CYP3A4, and CYP4F2 were not altered by any cadmium concentrations tested at 48h. Cadmium caused a reduction in cell viability at concentrations above 10μM. In conclusion although cultured PTC, do express CYP proteins, (CYP2E1, CYP3A4, and CYP4F2), Cd-induced cell stress as indicted by induction of HO-1 and MT does not alter expression of these CYP proteins at 48h.

Impact of Cadmium on Intracellular Zinc Levels in HepG2 Cells: Quantitative Evaluations and Molecular Effects

Cadmium is classified as a human carcinogen, and its disturbance in zinc homeostasis has been well established. However, its extent as well as molecular mechanisms involved in cadmium carcinogenesis has yet to be fully clarified. To this end, we used the zinc specific probe Zinquin to visualize and to quantitatively evaluate changes in the concentration of labile zinc, in an in vitro model of human hepatic cells (HepG2) exposed to cadmium. A very large increase (+93%) of intracellular labile zinc, displaced by cadmium from the zinc proteome, was measured when HepG2 were exposed to 10 µM cadmium for 24 hrs. Microarray expression profiling showed that in cells, featuring an increase of labile zinc after cadmium exposure, one of the top regulated genes is Snail1 (+3.6), which is included in the adherens junction pathway and linked to cancer. In the same pathway MET, TGF-βR, and two members of the Rho-family GTPase, Rac, and cdc42 all implicated in the loss of adherence features and acquisition of migratory and cancer properties were regulated, as well. The microRNAs analysis showed a downregulation of miR-34a and miR-200a, both implicated in the epithelial-mesenchymal transition. These microRNAs results support the role played by zinc in affecting gene expression at the posttranscriptional level.

Organoselenocyanates and symmetrical diselenides redox modulators: Design, synthesis and biological evaluation

Oxidative stress (OS) and disturbed intracellular redox balance have been predominantly observed in different types of cancer, including hepatocellular carcinoma (HCC). Agents which can stop OS multi-stressor events and modulate the intracellular redox state are becoming a major focus in HCC prevention. Among them, compounds with glutathione peroxidase (GPx)-like activity are of particularly concern. We herein report the synthesis of novel series of organoselenocyanates and symmetrical diselenide antioxidants, inspired by the natural redox enzyme, GPx and the synthetic organoselenium ebselen antioxidants. Their cytotoxic activity was evaluated against Hep G2 cells and their antimicrobial activities were evaluated against Candida albicans (C. albicans) fungus as well as against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), gram-negative and gram-positive bacteria, respectively. These compounds were also tested for their antioxidant activities using 2,2-diphenyl-1-picrylhydrazyl (DPPH), GPx-like activity and bleomycin dependent DNA damage assays and a basic structure-activity relationship was subsequently established. The physicochemical parameters and drug-likeness were computed employing the Molinspiration online property calculation toolkit and MolSoft software. Interestingly, some compounds proved to be more cytotoxic than ebselen and the known anticancer drug 5-Fu and in the same time they showed similar, sometime even more, antifungal activity than the reference antifungal drugs. Among these compounds, compound 16 was considered to be the most interesting with free radical-scavenging activity comparable to ascorbic acid and a GPx-like activity similar to ebselen. As most of these compounds comply with Lipinski's Rule of Five, they promise good bioavailability, which needs to be studied as part of future investigations.

Cadmium Impairs p53 Activity in HepG2 Cells

Cadmium and cadmium compounds are contaminants of the environment, food, and drinking water and are important constituents of cigarette smoke. Cd exposure has also been associated with airborne particulate CdO and with Cd-containing quantum dots in medical therapy. Adverse cadmium effects reported in the literature have stimulated during recent years an ongoing discussion to better elucidate cadmium outcomes at cell and molecular level. The present work is designed to gain an insight into the mechanism of p53 impairment at gene and protein level to understand Cd-induced resistance to apoptosis. We used a hepatoma cell line (HepG2) derived from liver, known to be metal responsive. At genotoxic cadmium concentrations no cell cycle arrest was observed. The p53 at gene and protein level was not regulated. Fluorescence images showed that p53 was correctly translocated into the nucleus but that the p21^Cip1/WAF-1, a downstream protein of p53 network involved in cell cycle regulation, was not activated at the highest cadmium concentrations used. The miRNAs analysis revealed an upregulation of mir-372, an miRNA able to affect p21^Cip1/WAF-1 expression and promote cell cycle progression and proliferation. The role of metallothioneins and possible conformational changes of p53 are discussed.

Cholinium-based ionic liquids with pharmaceutically active anions

Ionic liquids with cholinium-based active pharmaceutical ingredients (API-ILs) were preparedviaa simple and sustainable two-step anion exchange reaction. The resulting salts have improved upon the chemical, physical and biopharmaceutical properties of the parent APIs.

Determination of optimal toxic concentration and accumulation of cadmium in broiler chicks

Cadmium is considered one of the most toxic, non biodegradable heavy metal for the human and animals. The purpose of the present study was to investigate the changes in biochemical parameters of blood and accumulation of cadmium in various tissue caused by various levels of dietary cadmium chloride (CdCl₂) in broiler chicks. CdCl₂ was administered through drinking water to broiler chicks. In spectral analysis, CdCl₂ treatment caused a significant increase in Glutamate pyruvate transaminase (GPT), creatinine and uric acid levels in all treated groups. Intriguingly, the GPT, creatinine, and uric acid levels were significantly higher at 75 mg/kg as compared to the groups treated with high doses (100, 125 and 150 mg/kg) of CdCl₂. Atomic Absorption Spectrophotometer (AAS) was used for the determination of Cd accumulation in kidney, liver and Breast muscles. AAS analysis revealed that Cd accumulation is increased in breast muscles as compared to liver and kidney at higher doses of Cd than 75 mg/kg.

Thirdhand smoke causes DNA damage in human cells

Exposure to thirdhand smoke (THS) is a newly described health risk. Evidence supports its widespread presence in indoor environments. However, its genotoxic potential, a critical aspect in risk assessment, is virtually untested. An important characteristic of THS is its ability to undergo chemical transformations during aging periods, as demonstrated in a recent study showing that sorbed nicotine reacts with the indoor pollutant nitrous acid (HONO) to form tobacco-specific nitrosamines (TSNAs) such as 4-(methylnitrosamino)-4-(3-pyridyl)butanal (NNA) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). The goal of this study was to assess the genotoxicity of THS in human cell lines using two in vitro assays. THS was generated in laboratory systems that simulated short (acute)- and long (chronic)-term exposures. Analysis by liquid chromatography-tandem mass spectrometry quantified TSNAs and common tobacco alkaloids in extracts of THS that had sorbed onto cellulose substrates. Exposure of human HepG2 cells to either acute or chronic THS for 24h resulted in significant increases in DNA strand breaks in the alkaline Comet assay. Cell cultures exposed to NNA alone showed significantly higher levels of DNA damage in the same assay. NNA is absent in freshly emitted secondhand smoke, but it is the main TSNA formed in THS when nicotine reacts with HONO long after smoking takes place. The long amplicon-quantitative PCR assay quantified significantly higher levels of oxidative DNA damage in hypoxanthine phosphoribosyltransferase 1 (HPRT) and polymerase β (POLB) genes of cultured human cells exposed to chronic THS for 24h compared with untreated cells, suggesting that THS exposure is related to increased oxidative stress and could be an important contributing factor in THS-mediated toxicity. The findings of this study demonstrate for the first time that exposure to THS is genotoxic in human cell lines.

Two-photon fluorescent probe for cadmium imaging in cells

A novel two-photon excited fluorescent probe for cadmium (named as TPCd) was designed and synthesized utilizing a prodan (6-acetyl-2-methoxynaphthalene) derivative as the two-photon fluorophore and an o-phenylenediamine derivative as the Cd(2+) chelator, which possessed favorable photophysical properties and good water-solubility. The probe was designed with a photoinduced electron transfer (PET) mechanism and thus was weakly fluorescent itself. After binding with Cd(2+) which blocked the PET process, the fluorescence intensity of the probe was enhanced by up to 15-fold under one-photon excitation (OPE) and 27-fold under two-photon excitation (TPE), respectively. The two-photon action cross-section (Φδ) of the TPCd-Cd complex at 740 nm reached 109 GM compared to 3.6 GM for free TPCd, indicating the promising prospect of the probe in two-photon application. TPCd chelated Cd(2+) with 1 : 1 stoichiometry, and the apparent dissociation constant (K(d)) was 6.1 × 10(-5) M for the one-photon mode and 7.2 × 10(-5) M for the two-photon mode. The probe responded to Cd(2+) over a wide linear range from 0.1 to 30 μM with a detection limit of 0.04 μM. High selectivity of the probe towards Cd(2+) was acquired in Tris-HCl/sodium phosphate buffer. The probe was pH-independent in the biologically relevant pH range and non-toxic to living cells at reasonable concentration levels, warranting its in vivo applications. Through two-photon microscopy imaging, the probe was successfully applied to detect Cd(2+) uptake in living HepG2 cells.

Impaired cell functions of hepatocytes incubated with plasma of septic patients

OBJECTIVE AND DESIGN

The development of liver failure is a major problem in septic patients. In this prospective clinical experimental study the hepatotoxicity of plasma from septic and non-septic patients was tested.

METHODS AND SUBJECTS

The basic test components consist of human liver cells (HepG2/C3A) used in a standardized microtiter plate assay. After incubation with patient's plasma viability of cells (XTT-test), the cytochrome 1A2 activity and synthesis of micro albumin were measured. Subjects (28) enrolled comprise the septic shock group (SSG, n=10), the non-septic group (NSG, n=5) and the healthy volunteers group (HVG, n=13).

RESULTS

The 28-day mortality was 30% in the SSG. The APACHE II-, SOFA-, and SAPS-scores and the values of bilirubin and prothrombin time as INR were significantly higher in the SSG than in the NSG. The cytochrome 1A2 activity and the release of albumin were significantly reduced in HepG2/C3A cells incubated with plasma of the SSG (p<0.05). The cytochrome 1A2 activities were higher in survivors compared to non-survivors at the time point 0 and were increasing in survivors and decreasing in non-survivors within 54 h in the SSG. In the SSG there was a significant decrease in IL-10 and IL-8 between inclusion and 54 h. Values of IL-6, TNF alpha and IL-10 were significantly lower in the NSG compared with the values of the SSG at inclusion and after 54 h.

CONCLUSION

The plasma of patients with septic shock impaired cellular functions of HepG2/C3A cells.

MAPK activation is involved in cadmium-induced Hsp70 expression in HepG2 cells

Cadmium is one of the most toxic elements to which man can be exposed at work or in the environment. By far, the most salient toxicological property of Cd is its exceptionally long half-life in the human body. Once absorbed, Cd accumulates in the human body, particularly in the liver and other vital organs. The cellular actions of Cd are extensively documented, but the molecular mechanisms underlying these actions are still not resolved. It is known that Cd activates the activator protein-1 (AP-1), but no data about the pathway involved are reported for liver. The objective was to provide a greater insight into the effect of cadmium on mitogen-activated protein kinases (MAPK's) involved in signal transduction, its relationship with AP-1 activation, and heat shock protein (Hsp) 70 expression, in HepG2 cells. AP-1 activation as a result of 5 microM CdCl(2) exposure was increased 24.5-fold over control cells after 4 h treatment. To investigate the role of the extracellular signal-regulated protein kinases (ERK's), c-Jun N-terminal kinases (JNK's) and p38 kinases in cadmium-induced AP-1 activation, specific MAPKs inhibitors were used. AP-1 activation decreased by 74% with ERK inhibition, by 83% with p38 inhibition, while inhibition of JNK decreased by 70%. Only ERK and JNK participated in Hsp70 production, conferring cell protection against cadmium damage.

Regulation of metallothioneins and ZnT-1 transporter expression in human hepatoma cells HepG2 exposed to zinc and cadmium

Essential and non-essential metals can affect vital cellular processes, when over-accumulated within the cells. For this reason, cells have evolved multiple protein sensors, transporters, and other type of proteins to regulate and control free metal homeostasis. Among these, metallothioneins (MT) and ZnT-1 transporter play a key role in the regulation of free Zn concentrations. Herewith, MT expression in Zn (170microM) and Cd (0.1 and 10microM) exposed HepG2 cells is analyzed and compared. In addition, the modulation and localization of the membrane transporter ZnT-1 has been investigated. MT-I and MT-II were up-regulated in response to both Zn and Cd exposure and, as expected, Cd represented the most potent inducer. Namely, 0.1microM Cd was able to up-regulate MT-I, and -II in a way comparable to 170microM Zn. This is in agreement with MT general function of metal-chelating protein, acting with higher tolerance to essential metals than to non-essential ones. ZnT-1 protein, a plasma membrane specific Zn transporter, was up-regulated as well by both Zn and Cd, although in the same way. Immunofluorescence technique provided evidence that high levels of ZnT-1 measured by biochemical techniques, are related to an increased localization of the transporter at the plasma membrane.

Molecular cloning and characterization of an ATP-binding cassette (ABC) transmembrane transporter from the white shrimp Litopenaeusvannamei

ATP-binding cassette transmembrane transporters (ABC transporters) have a potential role in drug and xenobiotic resistance. Here, we report for the first time the cloning of an ABC transporter from white shrimp Litopenaeusvannamei (designated LvABCG), along with a study of its phylogenetic relationships, and measurements of its expression in different shrimp tissues exposed to cadmium and pH stress (acidic and alkaline conditions). Sequence analysis showed that LvABCG shares many similarities with the white/ABC transmembrane transporter, including two conserved regions: a highly conserved ATP-binding cassette (ABC) and transmembrane domain (TMD). Spatial analyses of transcript levels for ABCG in shrimp tissues, using reverse transcript PCR, revealed the highest transcript level in the hepatopancreas, less in the intestine and stomach, and none in the other tissues examined. The ABC transporter mRNA transcript in the hepatopancreas of L.vannamei was significantly up-regulated after 1.5 h and 24 h of exposure to alkaline and acidic conditions, respectively. LvABCG was also induced in intestine, but was downregulated in the stomach under the alkaline treatment. Upon exposure to cadmium (4.25 micromol L(-1) and 8.5 micromol L(-1)) for 48 h, the mRNA expression of LvABCG was up-regulated 4.79-fold (at 6 h) and 2.09-fold (at 12 h) in the hepatopancreas. LvABCG was also induced in the stomach after exposure to 4.25 micromol L(-1) cadmium, but downregulated in the stomach and intestine after exposure to 8.5 micromol L(-1) cadmium. These findings indicate that LvABCG might play an important role in the physiological changes related to metabolism and cell detoxification that occur when Pacific white shrimp are exposed to cadmium and pH stress.

The inhibition effect of 2,3,7,8-tetrachlorinated dibenzo-p-dioxin-induced aryl hydrocarbon receptor activation in human hepatoma cells with the treatment of cadmium chloride

Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), considered as endocrine disruptors, tend to accumulate in fatty tissues. Dioxin-responsive element chemical activated luciferase gene expression assay (DRE-luciferase assay) has been recognized as a semi-quantitative method for screening dioxins for its fast and low-cost as compared with HRGC/HRMS. However, some problems with the bioassay, including specificity, detection variation resulted from different cleanup strategies, and uncertainty of false-negative or false-positive results, remain to be overcome. Cadmium is a prevalent environmental contaminant around the world. This study was aimed to examine the effects of cadmium on the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced activation of aryl hydrocarbon receptor (AhR)-mediated gene expression in human hepatoma cells (Huh7-DRE-Luc cells and Huh7 cells). Ethoxyresorufin-O-deethylase (EROD) and DRE-luciferase assay were employed to determine the enzyme activity of cytochrome P450 1A1 (CYP1A1) and activation of AhR, respectively. The results showed that Cd(2+) levels significantly inhibited the induction of TCDD-induced CYP1A1 and DRE luciferase activation in hepatoma cells. The 50% inhibited concentrations (IC(50)) of CdCl(2) were 0.414 microM (95% confidence interval (C.I.): 0.230-0.602 microM) in Huh7-DRE-Luc cells and 23.2 microM (95% C.I.: 21.7-25.4 microM) in Huh7 cells. Accordingly, prevention of interference with non-dioxin-like compounds in a DRE-luciferase assay is of great importance in an extensive cleanup procedure.

2-Amino-14,16-dimethyloctadecan-3-ol: in vitro bioactivity and bio-production by the fungus Fusarium avenaceum

2-Amino-14,16-dimethyloctadecan-3-ol (2-AOD-3-ol) belongs to the class of sphingosine analogue toxins, which is a class of toxins that is known among several fungal genera and some lower marine animals. Many sphingosine analogues have been shown to inhibit ceramide synthase through structural similarities with the substrates of the enzyme. The adverse effects of some analogues, e.g. the fumonisins, are a result of ceramide synthase inhibition. The primary aim of this work was to generate basic knowledge on the toxicity of 2-AOD-3-ol in vitro. The human hepatocarcinoma cell line Hep G2 and horse erythrocytes were used in order to achieve this aim. The second aim of this work was to gain insight into the capabilities of the fungus Fusarium avenaceum, a common contaminant of grain in Scandinavia, to produce the toxin under laboratory conditions on different grain species, and in the field. The metabolite was found to be cytotoxic in several assays (lower µM-range) that measure general cytotoxicity (Alamar Blue" assay, Neutral Red uptake, LDH leakage), but did not inhibit ceramide synthase as measured by the increase of the sphinganine/sphingosine ratio. The cellular membrane was likewise not found to be a primary target of the molecule. Strains of F. avenaceum produced up to 6.3 mg/g of 2-AOD-3-ol on wheat grain under controlled conditions in the laboratory, while only low amounts (<56 µg/kg) could be found in field samples.

Modulation of different stress pathways after styrene and styrene-7,8-oxide exposure in HepG2 cell line and normal human hepatocytes

Styrene is one of the most important monomers produced worldwide. IARC classified styrene as a possible carcinogen to humans (group 2B). Styrene-7,8-oxide (SO) is the main reactive metabolite of styrene, and it is found to be genotoxic in several in vitro test systems. Styrene and styrene-7,8-oxide (SO) toxicity to HepG2 cells was investigated by evaluating end-points such as heat shock proteins (Hsps), metallothioneins (MT), apoptosis-related proteins, accumulation of styrene within the cells and expression of two isoforms of cytochrome P450. The potential activity of styrene and styrene-7,8-oxide in modulating gene expression was also investigated. The results showed induction of Hsp70, metallothioneins, BclX(S/L) and c-myc expression and a decrease in Bax expression in HepG2 after treatments, confirming that these compounds activated protective mechanisms. Moreover, up-regulation of TGFbeta2 and TGFbetaRIII in HepG2 cells was found after exposure to styrene, while in human primary hepatocytes these genes were down-regulated after both treatments. Finally, it was found that styrene and SO treatments did not induce CYP1A2 and CYP2E1 protein expression. In conclusion, both compounds caused toxic stress in HepG2 cells, with SO being more toxic; in the meantime, a different effect of the two compounds in HepG2 cells and primary human hepatocytes was observed regarding their activity in gene modulation.