title: A bioluminescent cytotoxicity assay for assessment of membrane integrity using a proteolytic biomarker.
abstract: Measurement of cell membrane integrity has been widely used to assess chemical cytotoxity. Several assays are available for determining cell membrane integrity including differential labeling techniques using neutral red and trypan blue dyes or fluorescent compounds such as propidium iodide. Other common methods for assessing cytotoxicity are enzymatic "release" assays which measure the extra-cellular activities of lactate dehydrogenase (LDH), adenylate kinase (AK), or glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in culture medium. However, all these assays suffer from several practical limitations, including multiple reagent additions, scalability, low sensitivity, poor linearity, or requisite washes and medium exchanges. We have developed a new cytotoxicity assay which measures the activity of released intracellular proteases as a result of cell membrane impairment. It allows for a homogenous, one-step addition assay with a luminescent readout. We have optimized and miniaturized this assay into a 1536-well format, and validated it by screening a library of known compounds from the National Toxicology Program (NTP) using HEK 293 and human renal mesangial cells by quantitative high-throughput screening (qHTS). Several known and novel membrane disrupters were identified from the library, which indicates that the assay is robust and suitable for large scale library screening. This cytotoxicity assay, combined with the qHTS platform, allowed us to quickly and efficiently evaluate compound toxicities related to cell membrane integrity.
authors.affiliation: NIH Chemical Genomics Center, National Institutes of Health, 9800 Medical Center Drive, MSC 3370, Bethesda, MD 20892-3370, USA.
authors.forename: Ming-Hsuang
authors.initials: MH
authors.lastname: Cho
authors.forename: Andrew
authors.initials: A
authors.lastname: Niles
authors.forename: Ruili
authors.initials: R
authors.lastname: Huang
authors.forename: James
authors.initials: J
authors.lastname: Inglese
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Austin
authors.forename: Terry
authors.initials: T
authors.lastname: Riss
authors.forename: Menghang
authors.initials: M
authors.lastname: Xia
mesh_terms: D002460:Cell Line; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000187:drug effects*; D006801:Humans; D007668:Kidney / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D049449:Luminescence; D008163:Luminescent Measurements / Q000379:methods*; D050527:Mesangial Cells / Q000187:drug effects / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism; D018675:Toxicity Tests; D015262:Xenobiotics / Q000633:toxicity*
chemical_list: D015262:Xenobiotics; D010447:Peptide Hydrolases