title: Sense and sensibility: the use of cell death biomarker assays in high-throughput anticancer drug screening and monitoring treatment responses.
abstract: Cell-based screening allows identification of biologically active compounds, for example, potential anticancer drugs. In this review, various screening assays are discussed in terms of what they measure and how this affects interpretation and relevance. High-throughput (HT) assays of viability based on the reduction of exogenous substrates do not always reflect viability or cell number levels. Membrane integrity assays can be used for HT quantification of cell death, but are non-specific as to the death mode. Several HT assays monitor end point apoptosis. Screening libraries at a single concentration (micromolar) can prevent detection of potent apoptosis inducers, as high concentrations may induce mainly necrosis. Using monolayer cultures limits the significance of cell-based screening as the properties of monolayer cells differ from tumours in vivo. Spheroid cultures are more physiological, but are impractical for screening by conventional methods. The authors have developed an assay quantifying accumulation of a caspase-cleaved protein specific for epithelial cells. It provides an integrated measure of apoptosis in two- and three-dimensional cultures and can be used as a blood biomarker assay for tumour apoptosis in vivo.
authors.affiliation: Dept. of Oncology-Pathology, Karolinska Institute, Cancer Center Karolinska, S-171 76 Stockholm, Sweden. Mimmi.Shoshan@onkpat.ki.se.
authors.forename: Maria C
authors.initials: MC
authors.lastname: Shoshan
authors.forename: Associate Professor Principal Investigator Aleksandra Mandic
authors.initials: AP
authors.lastname: Havelka
authors.forename: Frank
authors.initials: F
authors.lastname: Neumann
authors.forename: Stig
authors.initials: S
authors.lastname: Linder