Ataxia telangiectasia and Rad3 related kinase drives both the early and the late DNA damage response to the monofunctional antitumor alkylator S23906

Daniele G. Soares (1) , Aude Battistella (1) , Celine J. Rocca (1) , Renata Matuo (1, 2) , Joao Ap Henriques (2, 3) , Annette K. Larsen (1) , Alexandre E. Escargueil (1)

1 UMRS893 - Centre de Recherche Saint-Antoine
2 Departamento de Biofisica
3 Instituto de biotecnologia

Numerous anticancer agents and environmental mutagens target DNA. Although all such compounds interfere with the progression of the replication fork and inhibit DNA synthesis, there are marked differences in the DNA damage response pathways they trigger, and the relative impact of the proximal or the distal signal transducers on cell survival is mainly lesion-specific. Accordingly, checkpoint kinase inhibitors in current clinical development show synergistic activity with some DNA-targeting agents, but not with others. Here, we characterize the DNA damage response to the antitumor acronycine derivative S23906 that forms monofunctional adducts with guanine residues in the minor groove of DNA. S23906 exposure is accompanied by specific recruitment of RPA at replication sites and rapid Chk1 activation. In contrast, neither MRN (Mre11-Rad50-Nbs1) nor ATM (ataxia-telangiectasia mutated), contributes to the initial response to S23906. Interestingly, genetic attenuation of ATR (ATM and RAD3-related) activity inhibits not only the early phosphorylation of histone H2AX and Chk1, but interferes also with the late phosphorylation of Chk2. Moreover, loss of ATR function or pharmacological inhibition of the checkpoint kinases by AZD7762 is accompanied by abrogation of the S-phase arrest and increased sensitivity towards S23906. These findings identify ATR as a central coordinator of the DNA damage response to S23906 and provide a mechanistic rational for combinations of S23906 and similar agents with checkpoint abrogators.

Mots clés: Life Sciences

Daniele G. Soares, Aude Battistella, Celine J. Rocca, Renata Matuo, Joao Ap Henriques, et al.. Ataxia telangiectasia and Rad3 related kinase drives both the early and the late DNA damage response to the monofunctional antitumor alkylator S23906: S23906 is a potent inducer of replication stress. Biochemical Journal, 2011, 437 (1), pp.63-73. ⟨10.1042/BJ20101770⟩. ⟨hal-00600760⟩