Cyclin E-induced replicative stress drives p53-dependent whole-genome duplication

Whole-genome duplication (WGD) is a frequent event in cancer evolution and an important driver of aneuploidy. The role of the p53 tumor suppressor in WGD has been enigmatic: p53 can block the proliferation of tetraploid cells, acting as a barrier to WGD, but can also promote mitotic bypass, a key step in WGD via endoreduplication. In wild-type (WT) p53 tumors, WGD is frequently associated with activation of the E2F pathway, especially amplification of CCNE1, encoding cyclin E1. Here, we show that elevated cyclin E1 expression causes replicative stress, which activates ATR- and Chk1-dependent G2 phase arrest. p53, via its downstream target p21, together with Wee1, then inhibits mitotic cyclin-dependent kinase activity sufficiently to activate APC/CCdh1 and promote mitotic bypass. Cyclin E expression suppresses p53-dependent senescence after mitotic bypass, allowing cells to complete endoreduplication. Our results indicate that p53 can contribute to cancer evolution through the promotion of WGD. [Display omitted] •Replicative stress from elevated cyclin E drives p53-dependent mitotic bypass•p53, via p21, promotes mitotic bypass by inhibiting cyclin-dependent kinase•Elevated cyclin E drives p53+/+ G1-arrested cells to complete endoreduplication•Cyclin E can therefore drive WGD in p53-proficient cells DNA replication stress-induced whole-genome duplication (WGD) requires p53 function, in contrast to WGD induced by DNA damage; these findings provide mechanistic insight into cancer genome evolution in p53+/+ tumors.