Application of Biological Modifiers to a Multiplexed, Human Cell-Based DNA Damage Assay Provides Mechanistic...

Area of Science:

• Toxicology and Pharmacology
• Molecular Biology
• Genetics and Genomics

Background:

• Established In Vitro MicroFlow and MultiFlow assays provide genotoxic mode of action (MoA) information.
• There is a need to move beyond MoA assessments to understand specific clastogenic mechanisms and molecular targets.
• Biological response modifiers can potentially elicit specific biomarker responses to reveal mechanistic insights.

Purpose of the Study:

• To test the hypothesis that perturbation signatures from biological response modifiers can reveal clastogenic mechanisms and molecular targets.
• To investigate the utility of combining In Vitro MicroFlow and MultiFlow assays with biological response modifiers for enhanced genotoxicity assessment.
• To explore the grouping of clastogens based on similar genotoxic mechanisms using biomarker response profiles.

Main Methods:

• Exposure of TK6 cells to 20 known clastogens in the presence and absence of four biological response modifiers (PARP inhibitor, CHK1 inhibitor, DNA-PK inhibitor, ROS scavengers).
• Flow cytometric analysis of multiple biomarkers including micronuclei, γH2AX, p-H3, p53 activation, and nuclei counts.
• Data processing using PROAST benchmark dose (BMD) software and unsupervised hierarchical clustering of biomarker potency metrics.

Main Results:

• Biomarker response profiles were generated for clastogen exposures with and without biological response modifiers.
• Unsupervised hierarchical clustering successfully grouped clastogens with similar genotoxic mechanisms based on collective biomarker potency.
• The study demonstrated the feasibility of using biological response modifiers to refine mechanistic insights into genotoxicity.

Conclusions:

• The combination of In Vitro MicroFlow and MultiFlow assays with biological response modifiers provides valuable mechanistic insights into chemical-induced genotoxicity.
• Perturbation signatures generated by biological response modifiers can help elucidate specific clastogenic mechanisms and identify molecular targets.
• This approach represents a significant advancement in understanding the complex pathways of DNA damage induced by chemicals.