pH3 and pH2AX Genotoxicity

Our pH3 and pH2AX assay is designed to detect the potential of genotoxicity and aid the elucidation of the mechanisms involved. 

Cyprotex delivers consistent, high quality data with the flexibility to adopt protocols based on specific customer requirements. 


Assessment of genotoxicity using pH3 and pH2AX biomarkers:

  • High Content Screening uses automated fluorescence microscopy to measure indicators of cellular health and quantify biomarkers.
  • Clastogens and aneugens are key classes of genotoxic agents. Clastogens directly damage DNA, resulting in double-stranded DNA breaks. Aneugens produce numerical chromosome aberrations, formally known as aneuploidy (the result of "lagging" chromosomes).
  • Phospho-histone 3 (pH3) is a marker of mitosis and cell cycle arrest during the G2/M phase. Aneugens have been shown to increase levels of pH31. Phospho-histone 2AX (pH2AX) is a marker for double-stranded DNA breaks, indicating direct DNA damage caused by clastogens and some aneugens.
  • HepG2 cells were selected due to their wild type p53 expression, shown to be important for accurate genotoxicity prediction2.


HCS Genotoxicity: pH3 & pH2AX Assay Protocol


Data from the pH3 & pH2AX Assay


1) Khoury L et al. (2016) Complementarity of phosphorylated histones H2AX and H3 quantification in different cell lines for genotoxicity screening. Arch Toxicol 90; 1983-1995
2) Kumari R et al., (2014) p53 regulation upon genotoxic stress: intricacies and complexities. Mol Cell Oncol 1(3); DOI: 10.4161/23723548.2014.969653


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Benjamin Park

Benjamin Park

Associate Principal Scientist

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Cyprotex enables and enhances the prediction of human exposure, clinical efficacy and toxicological outcome of a drug or chemical. By combining quality data from robust in vitro methods with contemporary in silico technology, we add value, context and relevance to the ADME-Tox data supplied to our partners in the pharmaceutical or chemical industries.