Evaluating In Vitro DNA Damage Using Comet Assay

J Vis Exp. 2017 Oct 11;(128):56450. doi: 10.3791/56450.


DNA damage is a common phenomenon for each cell during its lifespan, and is defined as an alteration of the chemical structure of genomic DNA. Cancer therapies, such as radio- and chemotherapy, introduce enormous amount of additional DNA damage, leading to cell cycle arrest and apoptosis to limit cancer progression. Quantitative assessment of DNA damage during experimental cancer therapy is a key step to justify the effectiveness of a genotoxic agent. In this study, we focus on a single cell electrophoresis assay, also known as the comet assay, which can quantify single and double-strand DNA breaks in vitro. The comet assay is a DNA damage quantification method that is efficient and easy to perform, and has low time/budget demands and high reproducibility. Here, we highlight the utility of the comet assay for a preclinical study by evaluating the genotoxic effect of olaparib/temozolomide combination therapy to U251 glioma cells.

Publication types

  • Video-Audio Media

MeSH terms

  • Comet Assay / methods*
  • DNA Damage / physiology*
  • Electrophoresis / methods*
  • Humans
  • Reproducibility of Results