ATR signaling mediates an S-phase checkpoint after inhibition of poly(ADP-ribose) polymerase activity

• Published in: DNA repair Vol. 6; no. 6; pp. 742 - 750
• Main Authors: Horton, Julie K., Stefanick, Donna F., Kedar, Padmini S., Wilson, Samuel H.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.06.2007; Elsevier
• Subjects: 1-Naphthylamine - analogs & derivatives; 1-Naphthylamine - pharmacology; ATR; Bacteriology; Base excision repair; Biological and medical sciences; Cell Cycle; Cell cycle, cell proliferation; Cell Division; Cell physiology; Cell signaling; Chk1; Dose-Response Relationship, Drug; Enzyme Inhibitors - pharmacology; Fibroblasts - metabolism; Flow Cytometry; Fundamental and applied biological sciences. Psychology; G2 Phase; Growth, nutrition, cell differenciation; Humans; Methyl Methanesulfonate; Microbiology; Molecular and cellular biology; Molecular genetics; Mutagenesis. Repair; Naphthalimides - pharmacology; PARP inhibitor; PARP-1; Phosphorylation; Poly(ADP-ribose) Polymerase Inhibitors; Poly(ADP-ribose) Polymerases - metabolism; Quinolones - pharmacology; S Phase; Signal Transduction; Time Factors; γH2AX; γH2AX; PARP inhibitor; Cell cycle; Methyl methanesulfonate; Chk1; PARP-1; Base excision repair; Cell signaling; ATR; Excision; Enzyme; Transferases; Glycosyltransferases; NAD; DNA; S Phase; ADP-ribosyltransferase; PARP-1;PARP inhibitor;Base excision repair;Methyl methanesulfonate;Cell cycle;Cell signaling;Chkl;ATR;γH2Ax; Inhibition; Repair; Pentosyltransferases
• ISSN: 1568-7864; 1568-7856
• DOI: 10.1016/j.dnarep.2006.12.015

Human fibroblasts, capable of expressing a kinase-dead form of ATR (ATRkd), can be sensitized to the cytotoxic effects of methyl methanesulfonate (MMS) by the PARP inhibitor 4-amino-1,8-naphthalimide (4-AN). The combination of MMS + 4-AN results in accumulation of cells in S-phase of the cell cycle and activation of Chk1. Inhibition of ATR activity by expression of ATRkd suppresses the S-phase accumulation and partially reverses the Chk1 phosphorylation. The results confirm involvement of an ATR-mediated damage response pathway in the MMS + 4-AN-induced S-phase cell cycle checkpoint in human fibroblasts. Consistent with this hypothesis, the inhibitors caffeine and UCN-01 also abrogate the ATR- and Chk1-mediated delay in progression through S-phase. In the absence of ATR-mediated signaling, MMS + 4-AN exposure results in a G 2/M arrest, rather than an S-phase checkpoint. Thus, whereas ATR mediates the S-phase response, it is not critical for arrest of cells in G 2/M.