Development of a fluorescence-based cellular apoptosis reporter

Methods Appl Fluoresc. 2018 Oct 24;7(1):015001. doi: 10.1088/2050-6120/aae6f8.

Abstract

Evasion of apoptosis is a hallmark of human cancer, and a desired endpoint of many anticancer agents is the induction of cell death. With the heterogeneity of cancer becoming increasingly apparent, to understand drug mechanisms of action and identify combination therapies in cell populations, the development of tools to assess drug effects at the single cell level is a necessity for future preclinical drug development. Herein we describe the development of pCasFSwitch, a genetically encoded reporter construct designed to identify cells undergoing caspase-3 mediated apoptosis, by a translocation of a GFP signal from the cell membrane into the nucleus. Anticipated cellular distribution was demonstrated by use of confocal microscopy and cleavage by caspase-3 was shown to be required for the translocation of the GFP signal seen in apoptotic cells. Quantification of apoptosis using the construct revealed similar levels to that obtained with a commercially available apoptosis imaging agent (22.6% versus 20.3%). Moreover, we demonstrated its capacity for use in a high-throughput setting making it a powerful tool for drug development pipelines.

MeSH terms

  • Animals
  • Apoptosis / physiology*
  • Base Sequence
  • Caspase 3 / metabolism*
  • Cell Line, Tumor
  • Cell Membrane / metabolism
  • Cell Nucleus / metabolism
  • Fluorescence
  • Genes, Reporter / genetics*
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism*
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Mice
  • Microscopy, Confocal / methods
  • Microscopy, Fluorescence / methods
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism*
  • Single-Cell Analysis / methods

Substances

  • Membrane Proteins
  • Nuclear Proteins
  • Recombinant Fusion Proteins
  • Green Fluorescent Proteins
  • Casp3 protein, mouse
  • Caspase 3