title: Drugs with anti-oxidant properties can interfere with cell viability measurements by assays that rely on the reducing property of viable cells.
abstract: Cell viability assays such as Cell Titer Blue and Alamar Blue rely on the reducing property of viable cells to reduce the reagent dye to a product which gives a fluorescent signal. The current manufacture-recommended protocols do not take into account the possibility of the reagent substrate being reduced directly to the fluorescent product by drugs with an anti-oxidant property. After suspecting spurious results while determining the cytotoxic potential of a drug of interest (DOI) with known anti-oxidant property against a renal cell cancer (RCC) cell line, we aimed to establish that drugs with anti-oxidant property can indeed cause false-negative results with the current protocols of these assays by direct reduction of the reagent substrate. We also aimed to counter the same with a simple modification added to the protocol. Through our experiments, we conclusively demonstrate that drugs with anti-oxidant properties can indeed interfere with cell viability measurements by assays that rely on the reducing property of viable cells. A simple modification in the protocol, as elaborated in the manuscript, can prevent spurious results with these otherwise convenient assays.Laboratory Investigation advance online publication, 27 February 2017; doi:10.1038/labinvest.2017.18.
authors.affiliation: Division of Hematology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Niraj
authors.initials: N
authors.lastname: Shenoy
authors.affiliation: Division of Hematology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Mary
authors.initials: M
authors.lastname: Stenson
authors.affiliation: Division of Hematology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Joshua
authors.initials: J
authors.lastname: Lawson
authors.affiliation: Division of Hematology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Jithma
authors.initials: J
authors.lastname: Abeykoon
authors.affiliation: Division of Hematology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Mrinal
authors.initials: M
authors.lastname: Patnaik
authors.affiliation: Division of Hematology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Xiaosheng
authors.initials: X
authors.lastname: Wu
authors.affiliation: Division of Hematology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Witzig