title: Validation of a novel assay for checkpoint responses: characterization of camptothecin derivatives in Saccharomyces cerevisiae.
abstract: The evolutionary conservation of pathways preserving genetic stability supports the use of a lower eukaryote such as the yeast Saccharomyces cerevisiae in screening for novel anti-neoplastic agents. Yeast is already established as a model system to characterize the cellular effects of the topoisomerase inhibitor and anti-cancer agent camptothecin (CPT). Here, we demonstrate that a recently developed two-hybrid based plate assay that visualizes the DNA damage-induced homomeric complex formation of the yeast checkpoint protein Rad17 correctly predicts the biological activity of the tested camptothecin derivatives. The used criteria for biological activity include lethality, cell cycle arrest and Rad53p phosphorylation, an essential signaling event during checkpoint activation. Surprisingly, although responsive to camptothecin and not without influence on drug sensitivity, Rad17p appears to be dispensable for cell cycle arrest and for Rad53p phosphorylation following treatment with camptothecin. Such a role is only uncovered if double-strand break repair is compromised.
authors.affiliation: Department of Radiation Oncology and Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, USA.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.forename: Wolfram
authors.initials: W
authors.lastname: Siede
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D002166:Camptothecin / Q000494:pharmacology*; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism*; D004249:DNA Damage; D004271:DNA, Fungal / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins; D004789:Enzyme Activation; D017353:Gene Deletion; D009154:Mutation; D009687:Nuclear Proteins; D010766:Phosphorylation; D011237:Predictive Value of Tests; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D013329:Structure-Activity Relationship
chemical_list: D000970:Antineoplastic Agents; D018797:Cell Cycle Proteins; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; C501395:RAD17 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D002166:Camptothecin