Applications of CometChip for Environmental Health Studies

Abstract

Environmental exposures have long been known to impact public health and safety. For example, exposures to airborne particulates, heavy metals in water, or certain industrial chemicals can contribute to aging and to risk of developing cancer and other diseases. Environmental factors can impact health in a variety of ways, but a key concern is DNA damage, which can lead to mutations that cause cancer. Cancer can take years to develop following chemical exposure; however, one way to predict carcinogenicity in a more practical time frame is by studying the chemical's ability to induce DNA damage. The comet assay (or single-cell gel electrophoresis assay) has been used successfully for genotoxicity testing. The comet assay allows for the detection of DNA strand breaks via analysis of DNA migration during electrophoresis. Previously, the Engelward laboratory, in collaboration with the Bhatia laboratory, developed the CometChip for measurements of DNA damage and repair. The CometChip is a highthroughput comet assay that improves user reproducibility and significantly shortens total assay time. Here, we describe how the high-throughput CometChip platform can be used to measure DNA damage in established cell lines, animal models, and human samples. We also discuss technical challenges associated with these studies and provide recommendations on how to achieve optimal results for researchers interested in adopting this assay.

Measuring DNA modifications with the comet assay: a compendium of protocols

“…Recently, the CometChip protocol has been modified to detect bulky adducts using NER inhibitors in BPDE-treated cells 74 , and it has also been applied in hepatocyte spheroids 88 . A list of CometChip applications can be found in a report by Chao and Engelward 89 .…”

Evaluation of an in vitro three-dimensional HepaRG spheroid model for genotoxicity testing using the high-throughput CometChip platform

“…The present study used 96-or 384-well ULA plates to develop 3D spheroids, since it is relatively easy to culture highly uniform spheroids in a high-throughput manner versus other methods (Ivanov et al, 2014). In addition, the 96-well CometChip platform, a recently developed high-throughput version of the comet assay, provides a rapid and sensitive method of measuring DNA damage with better reproducibility (Chao and Engelward, 2020). We envisioned that the integration of the two technologies may improve the throughput of 3D assays significantly.…”

A Modern Genotoxicity Testing Paradigm: Integration of the High-Throughput CometChip® and the TGx-DDI Transcriptomic Biomarker in Human HepaRG™ Cell Cultures

“…Higher-throughput, mechanism-based genotoxicity tests in human cell culture models can aid in the interpretation of these assays to determine potential human risk. More recent advances to modernize genetic toxicity assays have begun to address this need; for example, the in vitro MicroFlow R micronucleus assay (25)(26)(27)(28) and the in vitro CometChip R assay (29)(30)(31)(32)(33) are compatible with various human and rodent cell lines and are relatively higher-throughput methods to assess DNA damage.…”