Metabolic context regulates the competitive fitness of oncogenic PIK3CA mutant clones in the normal esophagus

Activating mutations in PIK3CA generate large clones in the aging human esophagus. Here we investigate the underlying cellular mechanisms regulating their expansion by lineage tracing. Expression of an activating heterozygous Pik3caH1047R mutation in single progenitor cells of the mouse esophagus tilts cell fate towards proliferation, generating mutant clones that outcompete their wild type neighbours. The mutation leads to increased aerobic glycolysis through the activation of Hif1α transcriptional targets. In vitro and in vivo interventions that level out differences in activation of the PI3K/HIF1α/aerobic glycolysis axis between wild type and Pik3caH1047R cells attenuate the competitive advantage of the mutants. In contrast, metabolic conditions that alter Insulin/PI3K signalling, such as type-1 diabetes or diet-induced insulin resistance, further increase Pik3caH1047R mutant competitiveness in mice. Consistently, the density of activating PIK3CA mutations in human esophagus is increased in overweight individuals. We conclude that the metabolic environment influences the mutational landscape of normal epithelia. Clinically feasible interventions that even out signalling imbalances between wild type and mutant cells may therefore limit the expansion of oncogenic mutants in normal tissues.

• 157 samples
• DAC: EGAC00001000000
• Technology: Illumina HiSeq 2500