Competency of different cell models to predict human hepatotoxic drugs.
The liver is the most important target for drug-induced toxicity. This vulnerability results from functional liver features and its role in the metabolic elimination of most drugs. Drug-induced liver injury is a significant leading cause of acute, chronic liver disease and an important safety issue when developing new drugs.This review describes the advantages and limitations of hepatic cell-based models for early safety risk assessment during drug development. These models include hepatocytes cultured as monolayer, collagen-sandwich; emerging complex 3D configuration; liver-derived cell lines; stem cell-derived hepatocytes.In vitro toxicity assays performed in hepatocytes or hepatoma cell …
Human Upcyte Hepatocytes: Characterization of the Hepatic Phenotype and Evaluation for Acute and Long-Term Hepatotoxicity Routine Testing
The capacity of human hepatic cell-based models to predict hepatotoxicity depends on the functional performance of cells. The major limitations of human hepatocytes include the scarce availability and rapid loss of the hepatic phenotype. Hepatoma cells are readily available and easy to handle, but are metabolically poor compared with hepatocytes. Recently developed human upcyte hepatocytes offer the advantage of combining many features of primary hepatocytes with the unlimited availability of hepatoma cells. We analyzed the phenotype of upcyte hepatocytes comparatively with HepG2 cells and adult primary human hepatocytes to characterize their functional features as a differentiated hepatic …
High-content imaging technology for the evaluation of drug-induced steatosis using a multiparametric cell-based assay.
In the present study, we developed a cell-based protocol for the identification of drugs able to induce steatosis. The assay measures multiple markers of toxicity in a 96-well plate format using high-content screening (HCS) technology. After treating HepG2 cells with increasing concentrations of the tested compounds, toxicity parameters were analyzed using fluorescent probes: BODIPY493/503 (lipid content), 2',7'-dihydrodichlorofluorescein diacetate (reactive oxygen species [ROS] generation), tetramethyl rhodamine methyl ester (mitochondrial membrane potential), propidium iodide (cell viability), and Hoechst 33342 (nuclei staining). A total of 16 drugs previously reported to induce liver ste…
Assessment of the cytotoxic potential of an aqueous-ethanolic extract from Thalassia testudinum angiosperm marine grown in the Caribbean Sea
Abstract Objectives Reported antioxidant, anti-inflammatory and neuroprotective properties for one aqueous-ethanolic extract from Thalassia testudinum which grows in the Caribbean Sea compelled us to explore about extract cytotoxic effects. Methods Cell viability was assayed on tumour (HepG2, PC12, Caco-2 and 4T1) and non-tumour (VERO, 3T3, CHO, MCDK and BHK2) cell lines. The extract effects upon primary cultures of rat and human hepatocytes and human lymphocytes were assayed. Key findings The extract exhibited cytotoxicity against cancer cells compared to normal cells, and the IC50 values were 102 μg/ml for HepG2, 135 μg/ml for PC12, 165 μg/ml for Caco-2 and 129 μg/ml for 4T1 cells after 4…
Multiparametric evaluation of the cytoprotective effect of the Mangifera indica L. stem bark extract and mangiferin in HepG2 cells.
Abstract Objective Mango (Mangifera indica L.) stem bark extract (MSBE) is a natural product with biological properties and mangiferin is the major component. This paper reported the evaluation of the protective effects of MSBE and mangiferin against the toxicity induced in HepG2 cells by tert-butyl hydroperoxide or amiodarone. Method Nuclear morphology, cell viability, intracellular calcium concentration and reactive oxygen species (ROS) production were measured by using a high-content screening multiparametric assay. Key findings MSBE and mangiferin produced no toxicity below 500 mg/ml doses. A marked recovery in cell viability, which was reduced by the toxicants, was observed in cells pr…
Improved in vivo efficacy of clinical-grade cryopreserved human hepatocytes in mice with acute liver failure.
Clinical hepatocyte transplantation short-term efficacy has been demonstrated; however, some major limitations, mainly due to the shortage of organs, the lack of quality of isolated cells and the low cell engraftment after transplantation, should be solved for increasing its efficacy in clinical applications. Cellular stress during isolation causes an unpredictable loss of attachment ability of the cells, which can be aggravated by cryopreservation and thawing. In this work, we focused on the use of a Good Manufacturing Practice (GMP) solution compared with the standard cryopreservation medium, the University of Wisconsin medium, for the purpose of improving the functional quality of cells …
Metabolic activation and drug-induced liver injury:in vitroapproaches for the safety risk assessment of new drugs
Drug-induced liver injury (DILI) is a significant leading cause of hepatic dysfunction, drug failure during clinical trials and post-market withdrawal of approved drugs. Many cases of DILI are unexpected reactions of an idiosyncratic nature that occur in a small group of susceptible individuals. Intensive research efforts have been made to understand better the idiosyncratic DILI and to identify potential risk factors. Metabolic bioactivation of drugs to form reactive metabolites is considered an initiation mechanism for idiosyncratic DILI. Reactive species may interact irreversibly with cell macromolecules (covalent binding, oxidative damage), and alter their structure and activity. This r…
Foxa1 reduces lipid accumulation in human hepatocytes and is down-regulated in nonalcoholic fatty liver.
Triglyceride accumulation in nonalcoholic fatty liver (NAFL) results from unbalanced lipid metabolism which, in the liver, is controlled by several transcription factors. The Foxa subfamily of winged helix/forkhead box (Fox) transcription factors comprises three members which play important roles in controlling both metabolism and homeostasis through the regulation of multiple target genes in the liver, pancreas and adipose tissue. In the mouse liver, Foxa2 is repressed by insulin and mediates fasting responses. Unlike Foxa2 however, the role of Foxa1 in the liver has not yet been investigated in detail. In this study, we evaluate the role of Foxa1 in two human liver cell models, primary cu…
New microRNA Biomarkers for Drug-Induced Steatosis and Their Potential to Predict the Contribution of Drugs to Non-alcoholic Fatty Liver Disease
Background and Aims: Drug-induced steatosis is a major reason for drug failure in clinical trials and post-marketing withdrawal; and therefore, predictive biomarkers are essential. These could be particularly relevant in non-alcoholic fatty liver disease (NAFLD), where most patients show features of the metabolic syndrome and are prescribed with combined chronic therapies, which can contribute to fatty liver. However, specific biomarkers to assess the contribution of drugs to NAFLD are lacking. We aimed to find microRNAs (miRNAs) responsive to steatotic drugs and to investigate if they could become circulating biomarkers for drug induced steatosis. Methods: Human HepG2 cells were treated wi…
A Multi-Parametric Fluorescent Assay for the Screening and Mechanistic Study of Drug-Induced Steatosis in Liver Cells in Culture.
Human hepatic cells have been used for drug safety risk evaluations throughout early development phases. They provide rapid, cost-effective early feedback to identify drug candidates with potential hepatotoxicity. This unit presents a cell-based assay to evaluate the risk of liver damage associated with steatogenic drugs. Detailed protocols for cell exposure to test compounds and for the assessment of steatosis-related cell parameters (intracellular lipid content, reactive oxygen species production, mitochondrial impairment, and cell death) are provided. A few representative results that illustrate the utility of this procedure for the screening of drug-induced steatosis are shown. © 2017 b…
Development of multiparametric cell-based protocol to assess and classify hepatotoxicity potential of drugs
General Cytotoxicity Assessment by Means of the MTT Assay
Cytotoxicity assays were among the first in vitro bioassay methods used to predict toxicity of substances to various tissues. In vitro cytotoxicity testing provides a crucial means for safety assessment and screening, and for ranking compounds. The choice of using a particular cytotoxicity assay technology may be influenced by specific research goals. As such, four main classes of assays are used to monitor the response of cultured cells after treatment with potential toxicants. These methods measure viability, cell membrane integrity, cell proliferation, and metabolic activity. In this chapter, we focus on the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide tetrazolium reducti…
Customised in vitro model to detect human metabolism-dependent idiosyncratic drug-induced liver injury
Drug-induced liver injury (DILI) has a considerable impact on human health and is a major challenge in drug safety assessments. DILI is a frequent cause of liver injury and a leading reason for post-approval drug regulatory actions. Considerable variations in the expression levels of both cytochrome P450 (CYP) and conjugating enzymes have been described in humans, which could be responsible for increased susceptibility to DILI in some individuals. We herein explored the feasibility of the combined use of HepG2 cells co-transduced with multiple adenoviruses that encode drug-metabolising enzymes, and a high-content screening assay to evaluate metabolism-dependent drug toxicity and to identify…
Mechanism-based selection of compounds for the development of innovative in vitro approaches to hepatotoxicity studies in the LIINTOP project.
The 6th European Framework Programme project LIINTOP was specifically raised to optimise and provide established protocols and experimental in vitro models for testing intestinal and liver absorption, metabolism and toxicity of molecules of pharmacological interest. It has been focused on some of the most promising existing liver and intestine in vitro models with the aim of further improving their performance and thus taking them to a pre-normative research stage. Regarding the specific area of the liver, a first basic approach was the optimisation of in vitro hepatic models and the development and optimisation of in vitro approaches for toxicity screening. New advanced technologies have b…
Stem-cell derived hepatocyte-like cells for the assessment of drug-induced liver injury.
Drug-induced liver injury is a major cause of drug discovery failure in clinical trials and a leading cause of liver disease. Current preclinical drug testing does not predict hepatotoxicity which highlights the importance of developing highly predictive cell-based models. The use of stem cell technology and differentiation into hepatocyte-like cells (HLCs) could provide a stable source of hepatocytes for multiple applications, including drug screening. HLCs derived from both embryonic and induced pluripotent stem cells have been used to accurately predict hepatotoxicity as well as to test individual-specific toxicity. Although there are still many limitations, mainly related to the lack of…
Induced pluripotent stem cells in liver disease
Abstract The development of suitable and reproducible liver cell models is fundamental for regenerative medicine, drug screening, and disease modeling. Human primary hepatocytes are the gold standard not only for hepatic cell therapy but also for preclinical toxicological screening or the study of liver disease; however, their limited availability, variability, and phenotypic instability hamper their use. Recent advances in stem cell technology have allowed the generation of induced pluripotent stem cells (iPSCs) from different somatic cell types and their differentiation into hepatocyte-like cells (HLCs), which can provide unlimited cell source for their use in hepatology studies. We revie…
A robust reprogramming strategy for generating hepatocyte-like cells usable in pharmaco-toxicological studies.
Abstract Background High-throughput pharmaco-toxicological testing frequently relies on the use of established liver-derived cell lines, such as HepG2 cells. However, these cells often display limited hepatic phenotype and features of neoplastic transformation that may bias the interpretation of the results. Alternate models based on primary cultures or differentiated pluripotent stem cells are costly to handle and difficult to implement in high-throughput screening platforms. Thus, cells without malignant traits, optimal differentiation pattern, producible in large and homogeneous amounts and with patient-specific phenotypes would be desirable. Methods We have designed and implemented a no…
Development of a Multiparametric Cell-based Protocol to Screen and Classify the Hepatotoxicity Potential of Drugs
Hepatotoxicity is a major reason for drug nonapprovals and withdrawals. The multiparametric analysis of xenobiotic toxicity at the single cells level using flow cytometry and cellular imaging-based approaches, such as high-content screening (HCS) technology, could play a key role in the detection of toxicity and the classification of compounds based on patterns of cellular injury. This study aimed to develop and validate a practical, reproducible, in vitro multiparametric cell-based protocol to assess those drugs that are potentially hepatotoxic to humans and to suggest their mechanisms of action. The assay was applied to HepG2 human cell line cultured in 96-well plates and exposed to 78 di…
Steatotic liver: a suitable source for the isolation of hepatic progenitor cells.
Background: Alternative and/or complementary sources of cells such as hepatic progenitor cells (HPC) are under investigation for hepatic cell therapy purposes. Steatotic livers are those most commonly rejected for clinical transplantation and are also unsuitable for good quality hepatocyte isolation. Aim: Taken together these two facts, our aim was to investigate whether they could represent a suitable source for the isolation of progenitor cells. Methods: Rats fed for 7 weeks with methionine–choline deficient diets showing proved steatotic signs (i.e. increase in hepatic lipids; macrovesicular steatosis) and steatotic and normal human liver samples were used to study the expression of HPC …
Application of high-content screening for the study of hepatotoxicity: Focus on food toxicology
Safety evaluation of thousands of chemicals that are directly added to or come in contact with food is needed. Due to the central role of the liver in intermediary and energy metabolism and in the biotransformation of foreign compounds, the hepatotoxicity assessment is essential. New approach methodologies have been proposed for the safety evaluation of compounds with the idea of rapidly gaining insight into effects on biochemical mechanisms and cellular processes and screening large number of compounds. In this sense, high-content screening (HCS) is the application of automated microscopy and image analysis for better understanding of complex biological functions and mechanisms of toxicity…
Advantageous use of HepaRG cells for the screening and mechanistic study of drug-induced steatosis
Only a few in vitro assays have been proposed to evaluate the steatotic potential of new drugs. The present study examines the utility of HepaRG cells as a cell-based assay system for screening drug-induced liver steatosis. A high-content screening assay was run to evaluate multiple toxicity-related cell parameters in HepaRG cells exposed to 28 compounds, including drugs reported to cause steatosis through different mechanisms and non-steatotic compounds. Lipid content was the most sensitive parameter for all the steatotic drugs, whereas no effects on lipid levels were produced by non-steatotic compounds. Apart from fat accumulation, increased ROS production and altered mitochondrial membra…
Culture and Functional Characterization of Human Hepatoma HepG2 Cells
Hepatoma cell lines are frequently used as in vitro alternatives to primary human hepatocytes. Cell lines are characterized by their unlimited life span, stable phenotype, high availability, and easy handling. However, their major limitation is the lower expression of some metabolic activities compared with hepatocytes. HepG2 is a human hepatoma that is most commonly used in drug metabolism and hepatotoxicity studies. HepG2 cells are nontumorigenic cells with high proliferation rates and an epithelial-like morphology that perform many differentiated hepatic functions. In this chapter, freezing, thawing, and subculturing procedures for HepG2 cells are described. We further provide protocols …
Neonatal Livers: A Source for the Isolation of Good-Performing Hepatocytes for Cell Transplantation
Hepatocyte transplantation is an alternative therapy to orthotopic liver transplantation for the treatment of liver diseases. However, the supply of hepatocytes is limited given the shortage of organs available to isolate good-functioning quality cells. Neonatal livers may be a potential source alternative to adult livers to obtain good-performing hepatic cells for hepatocyte transplantation, which has not yet been explored profoundly. High-yield preparations of viable hepatocytes were isolated from 1- to 23-day-old liver donors, cryopreserved, and banked. Cell integrity and functional quality assessment were performed after thawing. Neonatal hepatocytes showed better postthawing recovery …
Upgrading cytochrome P450 activity in HepG2 cells co-transfected with adenoviral vectors for drug hepatotoxicity assessment
In a number of adverse drug reactions leading to hepatotoxicity, drug metabolism is thought to be involved by the generation of reactive metabolites from non-toxic drugs. The use of hepatoma cell lines, such as HepG2 cell line, for the evaluation of drug-induced hepatotoxicity is hampered by their low cytochrome P450 expression which makes impossible the study of the toxicity produced by bioactivable compounds. Genetically manipulated cells constitute promising tools for hepatotoxicity applications. HepG2 cells were simultaneously transfected with recombinant adenoviruses encoding CYP1A2, CYP2C9 and CYP3A4 to confer them drug-metabolic competence. Upgraded cells (Adv-HepG2) were highly able…
Upgrading HepG2 cells with adenoviral vectors that encode drug-metabolizing enzymes: application for drug hepatotoxicity testing.
Drug attrition rates due to hepatotoxicity are an important safety issue considered in drug development. The HepG2 hepatoma cell line is currently being used for drug-induced hepatotoxicity evaluations, but its expression of drug-metabolizing enzymes is poor compared with hepatocytes. Different approaches have been proposed to upgrade HepG2 cells for more reliable drug-induced liver injury predictions. Areas covered: We describe the advantages and limitations of HepG2 cells transduced with adenoviral vectors that encode drug-metabolizing enzymes for safety risk assessments of bioactivable compounds. Adenoviral transduction facilitates efficient and controlled delivery of multiple drug-metab…
Modulation of biotransformation and elimination systems by BM-21, an aqueous ethanolic extract from Thalassia testudinum, and thalassiolin B on human hepatocytes
Abstract BM-21 is an extract obtained from Thalassia testudinum marine plant with pharmacological properties. The effects of BM-21 and thalassiolin B (TB), its main component, on enzyme and transport proteins involved in drug metabolism and excretion in human cultured hepatocytes were evaluated. Cells were exposed for 48 h to sub-cytotoxic concentrations of BM-21 or TB. Effects on P450 isoforms revealed significant reductions of CYP1A2, 3A4 and 2D6 activities (up to 56%, 66% and 44% inhibition, respectively) after exposition to BM-21, no changes on CYP2A6 and 2C9 activities. TB produced a concentration-dependent reduction of all P450 activities. In addition, a decrease in total UGT and UGT2…