title: Validity of bioluminescence measurements for noninvasive in vivo imaging of tumor load in small animals.
abstract: A relatively new strategy to longitudinally monitor tumor load in intact animals and the effects of therapy is noninvasive bioluminescence imaging (BLI). The validity of BLIf or quantitative assessment of tumor load in small animals is critically evaluated in the present review. Cancer cells are grafted in mice or rats after transfection with a luciferase gene--usually that of a firefly. To determine tumor load, animals receive the substrate agent luciferin intraperitoneally, which luciferase converts into oxyluciferin in an ATP-dependent manner Light emitted by oxyluciferin in viable cancer cells is captured noninvasively with a highly sensitive charge-coupled device (CCD) camera. Validation studies indicate that BLI is useful to determine tumor load in the course of time, with each animal serving as its own reference. BLI is rapid, easy to perform, and sensitive. It can detect tumor load shortly after inoculation, even when relatively few cancer cells (2500-10,000) are used. BLI is less suited for the determination of absolute tumor mass in an animal because of quenching of bioluminescence by tissue components and the exact location of tumors because its spatial resolution is limited. Nevertheless, BLI is a powerful tool for high-throughput longitudinal monitoring of tumor load in small animals and allows the implementation of more advanced orthotopic tumor models in therapy intervention studies with almost the same simplicity as when measuring traditional ectopic subcutaneous models in combination with calipers.
authors.affiliation: Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Clara P W
authors.initials: CP
authors.lastname: Klerk
authors.forename: Renée M
authors.initials: RM
authors.lastname: Overmeer
authors.forename: Tatjana M H
authors.initials: TM
authors.lastname: Niers
authors.forename: Henri H
authors.initials: HH
authors.lastname: Versteeg
authors.forename: Dick J
authors.initials: DJ
authors.lastname: Richel
authors.forename: Tessa
authors.initials: T
authors.lastname: Buckle
authors.forename: Cornelis J F
authors.initials: CJ
authors.lastname: Van Noorden
authors.forename: Olaf
authors.initials: O
authors.lastname: van Tellingen
mesh_terms: D000818:Animals; D002452:Cell Count / Q000295:instrumentation / Q000379:methods* / Q000639:trends / Q000662:veterinary*; D004195:Disease Models, Animal; D006801:Humans; D008163:Luminescent Measurements / Q000295:instrumentation / Q000379:methods* / Q000639:trends / Q000662:veterinary*; D009367:Neoplasm Staging / Q000295:instrumentation / Q000379:methods / Q000639:trends / Q000662:veterinary*; D009369:Neoplasms / Q000473:pathology* / Q000662:veterinary*