Comet Assay for DNA Damage Assessment

A single-cell gel electrophoresis (comet assay) kit was employed for evaluating DNA damage (Trevigen, Inc.). Etoposide- or UV-treated or untreated MCF7 cells were resuspended in PBS and combined with molten low melting agarose at a ratio of 1:10 (v/v) and immediately pipetted 50 μl onto CometSlide. After cell lysis, samples were treated with NaOH solution (300 mM NaOH, 1mM EDTA) and applied to electrophoresis. Then the samples were stained with DAPI, and viewed by a fluorescence microscopy [50 (link)]. Images were analysed with an ImageJ software plugin Comet Assay from Microscopy Services Laboratory (https://www.med.unc.edu/microscopy) [57 (link)].