ARE-Nrf2 Luciferase Test Method (OECD TG 442D)

With the development of reliable in chemico/in vitro assays, manufacturers and formulators are now able to determine whether or not a substance is a skin sensitizing agent without the need for animal testing. Each of the available assays recapitulates some element of the adverse outcome pathway (AOP) associated with a skin sensitization response in humans. Using an integrated testing strategy that incorporates these approaches for identifying skin sensitization hazard risk (as outlined by the Globally Harmonized System of Classification and Labelling of Chemicals) ensures regulatory compliance as well as consumer safety and satisfaction.

Overview of ARE-Nrf2 Luciferase Test Method

The ARE-Nrf2 Luciferase Test is an in vitro test method that models the second key event in the skin sensitization adverse outcome pathway. When the skin is repeatedly exposed to a skin sensitizer, a sensitizing substance may cause skin cells (i.e., keratinocytes) to activate a protective gene pathway linked to skin sensitization. The more robust the keratinocyte response, the greater the sensitization potential of the substance.

The ARE-Nrf2 Luciferase Test measures the activation of this protective gene pathway—the antioxidant/electrophile response element (ARE) pathway—using luminescence-based detection. This assay uses a modified keratinocyte line that contains a luciferase gene under the transcriptional control of a constitutive promoter fused with the ARE element. When exposed to a sensitizer, endogenous Nrf2-dependent genes are activated. Luciferase-driven luminescence is well-documented to be dependent on Nrf2 expression. A Luminometer is used to quantify luciferase output in response to test materials. The ARE-Nrf2 Test classifies materials as positive for skin sensitization capacity if they induce a statistically significant luminescent signal that exceeds a defined threshold.

The ARE-Nrf2 Luciferase Test is suitable for testing multi-constituent substances and mixtures and is more likely to predict low to moderate skin sensitization potential as opposed to high skin sensitization potential. This assay also should be used in conjunction with additional assays to confidently determine a substance’s safety and skin sensitization potential.

Our Capabilities

CPT^SM is a state-of-the-art testing facility, including laboratories that specialize in Analytical, Clinical, and In-Vitro Toxicology testing. Our entire testing facility is at your disposal for evaluating skin sensitization potential.

In our highly experienced and specialized departments, we test a wide range of articles including pharmaceuticals, raw materials, cosmetic and personal care products. Our experts offer our clients guidance on the best testing strategies to ensure consumer safety and satisfaction as well as regulatory compliance.