6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 4 is essential for p53-null cancer cells

The bifunctional enzyme 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase-4 (PFKFB4) controls metabolic flux through allosteric regulation of glycolysis. Here we show that p53 regulates the expression of PFKFB4 and that p53-deficient cancer cells are highly dependent on the function of this enzyme. We found that p53 down-regulates PFKFB4 expression by binding to its promoter and mediating transcriptional repression via histone deacetylases. Depletion of PFKFB4 from p53 deficient cancer cells increased levels of the allosteric regulator fructose 2,6-bisphophate, leading to increased glycolytic activity but decreased routing of metabolites through the oxidative arm of the pentose phosphate pathway. PFKFB4 was also required to support the synthesis and regeneration of nicotinamide adenine dinucleotide phosphate (NADPH) in p53 deficient cancer cells. Moreover, depletion of PFKFB4 attenuated cellular biosynthetic activity and resulted in the accumulation of reactive oxygen species and cell death in the absence of p53. Finally, silencing of PFKFB4 induced apoptosis in p53 deficient cancer cells in vivo and interfered with tumour growth. These results demonstrate that PFKFB4 is essential to support anabolic metabolism in p53-deficient cancer cells and suggest that inhibition of PFKFB4 could be an effective strategy for cancer treatment. Overall design: Gene expression changes in HCT116 p53+/+ and p53-/- xenograft tumours after PFKFB4 silencing

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Ros S, Flöter J, Kaymak I, Da Costa C, Houddane A, Dubuis S, Griffiths B, Mitter R, Walz S, Blake S, Behrens A, Brindle KM, Zamboni N, Rider MH, Schulze A