ToxReporter Cell Lines for Early, Mechanistic Drug Safety Screening
Would you like to be able to screen multiple discovery compounds for toxicity in a mechanistic way, using a simple cell-based assay? The ToxReporter cell lines allow direct measurement of induction of ten pathways linked to specific toxicological responses (e.g. oxidative stress, DNA damage, xenobiotic response) via a simple ELISA on the cell culture medium. Additionally, metabolite-mediated toxicity can be detected via transient expression of multiple human CYP450s in the cell lines.
The ToxReporter cell lines are freely available to license. For customers who have a limited number of compounds to screen or wish to perform an initial evaluation study, the cell lines can be accessed on a fee-for-service basis.
ToxReporter cell line technology
All cellular responses – both beneficial and toxic – are controlled by a complex network of signalling cascades. Effects of chemicals on these pathways can be measured in cells by developing reporter systems, where the promoter of a gene activated by one of these pathways is linked to a reporter biomarker.
In collaboration with Millipore Inc., CXR has developed a panel of novel in vitro reporter systems using a soluble reporter protein as the biomarker (Fig I). This panel can detect responses such as:
The reporter cell lines can therefore be used to generate mechanistic information on the properties of a compound or series of compounds. In particular, the cell lines can be used to:
The easily-measured biomarker is attached to a gene promoter region in such a way that, when there is a change in expression of that particular gene, this is reflected by an increase or decrease in levels of the marker. The biomarker can be detected in the culture medium using commercially-available ELISA assays (Fig II). Ten cell lines containing promoters associated with oncogenic / cytoprotective / toxic response pathways have been developed (see below).
Fig II
What if toxicity is not mediated by the parent compound, but by toxic metabolites? Critically, CXR can add human-specific metabolism to the cell lines: multiple human CYP450s enzymes can be expressed via transient transfection with an adenoviral construct.
Reporter Cell Line Advantages
Easy & simple measurement | · Directly from cell culture medium – no preparation of sample needed · Simple ELISA assay to measure soluble reporter protein (widely available commercial kits) |
Accuracy | · Little to no constitutive expression of soluble reporter protein, high induced expression · Production/induction of soluble reporter protein reflects test item effects |
Multiple mechanistic models available | · 10 validated reporter lines currently available to enable the identification of mechanisms of action and toxicity · Complementary screens possible. For example, using the ARE line to screen for induction of antioxidant pathways and the p21 line to screen for DNA damage gives mechanistic information as to whether your compound is a protective anti-oxidant or an electrophile |
Time-dependent response | · Flexible measurement system enabling multiple timepoint sampling · Reflects time-dependent effects of test item |
Flexibility to measure Up or Down-regulation | · Up-regulation – simple incubation with test item · Down-regulation – co-incubation with known inducers of stress response |
Reactive metabolite detection | · Assay cell lines can be transfected with a choice of human cytochrome P450s to evaluate metabolites · Comparison with control, P450 free cells can demonstrate reactive metabolite effect |
Available Reporter Cell Lines
Biological Process | Promoter/Enhancer | Cell Line | |
Oxidative Stress, Antioxidant Response | Antioxidant Response Element (ARE) | Tox_ARE Reporter Cell Line | • Cellular response to electrophilic compounds, xenobiotics and antioxidants |
Hmox1 | Tox_Hmox1 Reporter Cell Line | • Cellular response to oxidative stress |
Inflammation & Immunity | NFkB | Tox_NFkB Reporter Cell line | • Immune responses, inflammation, cell growth, apoptosis, tumorigenesis |
Cell Cycle Control, DNA Damage, Apoptosis | TPA Response Element (AP-1) | Tox_AP-1 Reporter Cell line | • Proliferation, survival, differentiation and transformation |
p53 | Tox_p53 Reporter Cell Line | • Cell cycle control, DNA damage and apoptosis |
Cyclin-dependent kinase inhibitor-1A p21-waf1 | Tox_p21 Reporter Cell line | • DNA damage, cell cycle control |
Angiogenesis, Hypoxia | Hypoxia Response Element | Tox_HRE Reporter Cell Line | • Angiogenesis, glucose metabolism, cell proliferation/survival and invasion/metastasis |
Toxic and other stress responses | Xenobiotic Response Element | Tox_XRE Reporter Cell Line | • Response to particular classes of toxic and carcinogenic compounds |
Heat Shock Protein 70 | Tox_HSP70 Reporter Cell line | • General cellular response to stress, toxic response to e.g. heavy metals |
Cell Growth & Differentiation | Glucocorticoid Response Element | Tox_GRE Reporter Cell line | • Cell growth & differentiation |
Considerable technical expertise and experimental know-how has identified the optimal:
- Cell line for each promoter
- Promoter sequence
- Promoter repeat number
The above lines cover the major pathways of cytoprotection and cellular stress, and have been created as a result of collaborations with Millipore Inc. These lines are available for sub-licensing or fee-for-service work.
If you would like further information on these cell lines, fee-for-service prices or licensing terms, please contact CXR at info@cxrbiosciences.com or phone +44 (0) 1382 432 163.
Download ToxReporter Cell Line Flyer
AREc32 cell line.
AREc32 cell line. A luciferase reporter cell line for compounds that induce oxidative stress (e.g. potential skin sensitisers), and compounds with cytoprotective properties.
Toxicity reporter mice.
In vivo models for the rapid assessment of potential mechanisms of toxicity. The promoters of genes activated in response to toxic agents have been linked to proprietary reporters, to provide rapid
in vivo methods for the assessment of candidate compounds.
Fig I 
