title: Induction of DNA damage responses by adozelesin is S phase-specific and dependent on active replication forks.
abstract: Adozelesin is an alkylating minor groove DNA binder that is capable of rapidly inhibiting DNA replication in treated cells through a trans-acting mechanism and preferentially arrests cells in S phase. It has been shown previously that in cells treated with adozelesin, replication protein A (RPA) activity is deficient, and the middle subunit of RPA is hyperphosphorylated. The adozelesin-induced RPA hyperphosphorylation can be blocked by the replicative DNA polymerase inhibitor, aphidicolin, suggesting that adozelesin-triggered cellular DNA damage responses require active DNA replication forks. These data imply that cellular DNA damage responses to adozelesin treatment are preferentially induced in S phase. Here, we show that RPA hyperphosphorylation, RPA intranuclear focalization, and gamma-H2AX intranuclear focalization induced by adozelesin treatment are all dependent on DNA replication fork progression, and focalization is only induced in S phase cells. These findings are similar to those seen with the S phase-specific DNA-damaging agent, camptothecin. Conversely, all three DNA damage responses are independent of either S phase or replication fork progression when induced by treatment with the DNA strand scission agent, C-1027. Furthermore, we demonstrate that adozelesin-induced RPA and gamma-H2AX intranuclear foci appear to colocalize within the nuclei of S phase cells.
authors.affiliation: Departments of Microbiology and Biochemistry and the Witebsky Center for Microbial Pathogenesis and Immunology, University at Buffalo, SUNY, School of Medicine and Biomedical Sciences, Buffalo, New York 14214, USA.
authors.forename: Jen-Sing
authors.initials: JS
authors.lastname: Liu
authors.forename: Shu-Ru
authors.initials: SR
authors.lastname: Kuo
authors.forename: Terry A
authors.initials: TA
authors.lastname: Beerman
authors.forename: Thomas
authors.initials: T
authors.lastname: Melendy
mesh_terms: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents / Q000633:toxicity; D000903:Antibiotics, Antineoplastic / Q000633:toxicity; D018906:Antineoplastic Agents, Alkylating / Q000633:toxicity*; D016590:Aphidicolin / Q000494:pharmacology; D001572:Benzofurans; D002166:Camptothecin / Q000633:toxicity*; D003509:Cyclohexanecarboxylic Acids / Q000633:toxicity*; D053138:Cyclohexenes; D004249:DNA Damage; D004261:DNA Replication / Q000187:drug effects*; D000080890:Duocarmycins; D053281:Enediynes; D006367:HeLa Cells; D006801:Humans; D007211:Indoles; D016196:S Phase / Q000187:drug effects
chemical_list: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D000903:Antibiotics, Antineoplastic; D018906:Antineoplastic Agents, Alkylating; D001572:Benzofurans; D003509:Cyclohexanecarboxylic Acids; D053138:Cyclohexenes; D000080890:Duocarmycins; D053281:Enediynes; D007211:Indoles; C058024:C 1027; D016590:Aphidicolin; C060090:adozelesin; D002166:Camptothecin