Citrate oscillations during cell cycle are a targetable vulnerability in cancer cells

Abstract

Cell cycle progression is timely interconnected with oscillations in cellular metabolism. Here, we first describe how these metabolic oscillations allow cycling cells to meet the bioenergetic needs specifically for each phase of the cell cycle. In parallel, we highlight how the cytosolic level of citrate is dynamically regulated during these different phases, being low in G1 phase, increasing in S phase, peaking in G2/M, and decreasing in mitosis. Of note, in cancer cells, a dysregulation of such citrate oscillation can support cell cycle progression by promoting a deregulated Warburg effect (aerobic glycolysis), activating oncogenic signaling pathways (such as PI3K/AKT), and promoting acetyl-CoA production via alternative routes, such as overconsumption of acetate. Then, we review how administration of sodium citrate (at high doses) arrests the cell cycle in G0/G1 or G2/M, inhibits glycolysis and PI3K/AKT, induces apoptosis, and significantly reduces tumor growth in various in vivo models. Last, we reason on the possibility to implement citrate administration to reinforce the effectiveness of cell cycle inhibitors to better cure cancer.