Loss of p53 suppresses replication-stress-induced DNA breakage in G1/S checkpoint deficient cells

Bente Benedict, Tanja van Harn, Marleen Dekker, Simone Hermsen, Asli Kucukosmanoglu, Wietske Pieters, Elly Delzenne-Goette, Josephine C. Dorsman, Eva Petermann, Floris Foijer, Hein te Riele

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In cancer cells, loss of G1/S control is often accompanied by p53 pathway inactivation, the latter usually rationalized as a necessity for suppressing cell cycle arrest and apoptosis. However, we found an unanticipated effect of p53 loss in mouse and human G1-checkpoint-deficient cells: reduction of DNA damage. We show that abrogation of the G1/S-checkpoint allowed cells to enter S-phase under growth-restricting conditions at the expense of severe replication stress manifesting as decelerated DNA replication, reduced origin firing and accumulation of DNA double-strand breaks. In this system, loss of p53 allowed mitogen-independent proliferation, not by suppressing apoptosis, but rather by restoring origin firing and reducing DNA breakage. Loss of G1/S control also caused DNA damage and activation of p53 in an in vivo retinoblastoma model. Moreover, in a teratoma model, loss of p53 reduced DNA breakage. Thus, loss of p53 may promote growth of incipient cancer cells by reducing replication-stress-induced DNA damage.
Original languageEnglish
Publication statusPublished - 2018

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