Oncogenic PIK3CA induces centrosome amplification and tolerance to genome doubling
journal contributionposted on 2021-08-17, 11:27 authored by Inma M Berenjeno, Roberto Piñeiro, Sandra D Castillo, Wayne Pearce, Nicholas McGranahan, Sally M Dewhurst, Valerie Meniel, Nicolai J Birkbak, Evelyn Lau, Laurent Sansregret, Daniele Morelli, Nnennaya Kanu, Shankar Srinivas, Mariona Graupera, Victoria ER Parker, Karen G Montgomery, Larissa S Moniz, Cheryl L Scudamore, Wayne A Phillips, Robert K Semple, Alan Clarke, Charles Swanton, Bart Vanhaesebroeck
Mutations in PIK3CA are very frequent in cancer and lead to sustained PI3K pathway activation. The impact of acute expression of mutant PIK3CA during early stages of malignancy is unknown. Using a mouse model to activate the Pik3ca H1047R hotspot mutation in the heterozygous state from its endogenous locus, we here report that mutant Pik3ca induces centrosome amplification in cultured cells (through a pathway involving AKT, ROCK and CDK2/Cyclin E-nucleophosmin) and in mouse tissues, and increased in vitro cellular tolerance to spontaneous genome doubling. We also present evidence that the majority of PIK3CA H1047R mutations in the TCGA breast cancer cohort precede genome doubling. These previously unappreciated roles of PIK3CA mutation show that PI3K signalling can contribute to the generation of irreversible genomic changes in cancer. While this can limit the impact of PI3K-targeted therapies, these findings also open the opportunity for therapeutic approaches aimed at limiting tumour heterogeneity and evolution.