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Updated: Jun 21, 2026
High Content Screening Analysis to Evaluate the Toxicological Effects of Harmful and Potentially Harmful Constituents (HPHC)
Published on: May 10, 2016
Analysis of 75 marketed pharmaceuticals using the GADD45a-GFP 'GreenScreen HC' genotoxicity assay
Paul W Hastwell1, Thomas W Webster, Matthew Tate
1Genetic Toxicology, GlaxoSmithKline plc, Hertfordshire SG12 0DP, UK. paul.w.hastwell@gsk.com
Abstract:
The GADD45a-GFP (GreenScreen HC) reporter assay detects genotoxic damage in the human lymphoblastoid TK6 cell line and gives positive results for all classes of genotoxin, including mutagens, aneugens and clastogens. In this study, a collection of 75 marketed pharmaceuticals were tested in the assay. Compounds in the collection represent a broad range of chemical structures, pharmacologies and therapeutic indications, including neoplasia and viral infection where positive genotoxicity results are often associated with the pharmacological activity. Based on the results of this study, two main conclusions can be drawn: (i) the GreenScreen HC is more predictive of in vivo genotoxicity (88%) and genotoxic carcinogenicity (93%) data than the any of the other regulatory in vitro genotoxicity assay and (ii) no compounds were uniquely positive in the GADD45a-GFP assay. This analysis therefore provides additional evidence to support the use of the GADD45a-GFP assay as an effective tool either in early genotoxic liability identification or non-clinical safety assessment of candidate pharmaceuticals during development.
Insights
The GreenScreen HC assay effectively identifies genotoxic pharmaceuticals, showing high prediction rates for in vivo genotoxicity and carcinogenicity. This reporter assay is a valuable tool for early safety assessments in drug development.
Area of Science:
- Toxicology
- Pharmacology
- Molecular Biology
Background:
- Genotoxicity testing is crucial for pharmaceutical safety assessment.
- Existing in vitro assays have limitations in predicting in vivo outcomes.
- The GADD45a-GFP (GreenScreen HC) reporter assay detects DNA damage.
Purpose of the Study:
- To evaluate the predictive accuracy of the GreenScreen HC assay for genotoxicity and genotoxic carcinogenicity.
- To assess the performance of the GreenScreen HC assay using a diverse set of marketed pharmaceuticals.
Main Methods:
- A collection of 75 marketed pharmaceuticals was tested using the GADD45a-GFP (GreenScreen HC) reporter assay.
- The assay detects genotoxic damage in the human lymphoblastoid TK6 cell line.
- Results were compared against existing in vivo genotoxicity and genotoxic carcinogenicity data.
Main Results:
- The GreenScreen HC assay demonstrated high predictive accuracy: 88% for in vivo genotoxicity and 93% for genotoxic carcinogenicity.
- The assay detected all classes of genotoxins, including mutagens, aneugens, and clastogens.
- No compounds tested were found to be uniquely positive in the GreenScreen HC assay compared to other regulatory assays.
Conclusions:
- The GreenScreen HC assay is a highly predictive tool for genotoxicity and genotoxic carcinogenicity.
- It outperforms other regulatory in vitro genotoxicity assays in predicting in vivo outcomes.
- The assay is suitable for early genotoxic liability identification and non-clinical safety assessment of pharmaceuticals.
