Application of a new approach methodology (NAM)-based strategy for genotoxicity assessment of data-poor compounds

Copyright © 2023 His Majesty the King in Right of Canada..

The conventional battery for genotoxicity testing is not well suited to assessing the large number of chemicals needing evaluation. Traditional in vitro tests lack throughput, provide little mechanistic information, and have poor specificity in predicting in vivo genotoxicity. New Approach Methodologies (NAMs) aim to accelerate the pace of hazard assessment and reduce reliance on in vivo tests that are time-consuming and resource-intensive. As such, high-throughput transcriptomic and flow cytometry-based assays have been developed for modernized in vitro genotoxicity assessment. This includes: the TGx-DDI transcriptomic biomarker (i.e., 64-gene expression signature to identify DNA damage-inducing (DDI) substances), the MicroFlow® assay (i.e., a flow cytometry-based micronucleus (MN) test), and the MultiFlow® assay (i.e., a multiplexed flow cytometry-based reporter assay that yields mode of action (MoA) information). The objective of this study was to investigate the utility of the TGx-DDI transcriptomic biomarker, multiplexed with the MicroFlow® and MultiFlow® assays, as an integrated NAM-based testing strategy for screening data-poor compounds prioritized by Health Canada's New Substances Assessment and Control Bureau. Human lymphoblastoid TK6 cells were exposed to 3 control and 10 data-poor substances, using a 6-point concentration range. Gene expression profiling was conducted using the targeted TempO-Seq™ assay, and the TGx-DDI classifier was applied to the dataset. Classifications were compared with those based on the MicroFlow® and MultiFlow® assays. Benchmark Concentration (BMC) modeling was used for potency ranking. The results of the integrated hazard calls indicate that five of the data-poor compounds were genotoxic in vitro, causing DNA damage via a clastogenic MoA, and one via a pan-genotoxic MoA. Two compounds were likely irrelevant positives in the MN test; two are considered possibly genotoxic causing DNA damage via an ambiguous MoA. BMC modeling revealed nearly identical potency rankings for each assay. This ranking was maintained when all endpoint BMCs were converted into a single score using the Toxicological Prioritization (ToxPi) approach. Overall, this study contributes to the establishment of a modernized approach for effective genotoxicity assessment and chemical prioritization for further regulatory scrutiny. We conclude that the integration of TGx-DDI, MicroFlow®, and MultiFlow® endpoints is an effective NAM-based strategy for genotoxicity assessment of data-poor compounds.

Medienart:

E-Artikel

Erscheinungsjahr:

2023

Erschienen:

2023

Enthalten in:

Zur Gesamtaufnahme - volume:5

Enthalten in:

Frontiers in toxicology - 5(2023) vom: 01., Seite 1098432

Sprache:

Englisch

Beteiligte Personen:

Fortin, Anne-Marie V [VerfasserIn]
Long, Alexandra S [VerfasserIn]
Williams, Andrew [VerfasserIn]
Meier, Matthew J [VerfasserIn]
Cox, Julie [VerfasserIn]
Pinsonnault, Claire [VerfasserIn]
Yauk, Carole L [VerfasserIn]
White, Paul A [VerfasserIn]

Links:

Volltext

Themen:

Data-poor compounds
Genetic toxicology
Human health risk assessment
Journal Article
Microflow
Multiflow
New approach methodologies (NAM)
TGx-DDI transcriptomic biomarker
Toxicogenomics (TGx)

Anmerkungen:

Date Revised 10.02.2023

published: Electronic-eCollection

Citation Status PubMed-not-MEDLINE

doi:

10.3389/ftox.2023.1098432

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM352661917