SRP174037 PRJNA510970 GSE124189 The mevalonate pathway is required for pyrimidine synthesis and survival of p53-deficient colon cancer cells in metabolically compromised environments In this study, we have investigated the effect of p53 deletion on the metabolic activity of colon cancer cells exposed to metabolic stress. In order to recreate the simultaneous reduction in oxygen and nutrient availability found in tumors, we cultured cancer cells as multicellular tumor spheroids. Under these conditions, p53 deficient cancer cells activate the expression of enzymes of the mevalonate pathway via the sterol regulatory element binding protein 2 (SREBP2). Moreover, inhibition of mevalonate pathway activity with statins selectively induced apoptosis in p53 deficient cancer cells exposed to metabolic stress. This effect was mediated by the requirement of p53 deficient cancer cells to synthesise ubiquinone (coenzyme Q10) to maintain TCA cycle activity, respiration and the production of pyrimidine nucleotides. Our study has revealed a novel link between isoprenoid synthesis by the mevalonate pathway and the electron transport function of ubiquinone, which is required for nucleotide biosynthesis. As a consequence, maintaining mevalonate pathway activity is essential for p53 deficient cancer cells to proliferate and survive under the metabolic constraints of the tumor microenvironment. Overall design: RNAseq experiments in HCT116 p53WT or -deficent cells analyzing gene expression changes in monolayer or 3D culture conditions and after treatment with simvastatin. GSE124189 pubmed 31744820