Nuances of PFKFB3 Signaling in Breast Cancer.

The enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3) is a critical engine that supports glucose catabolism. PFKFB3 produces the signaling molecule fructose-2,6-biphosphate (F2,6BP), which activates the second gatekeeper in glycolysis, 6-phosphofructo-1-kinase (PFK-1), and favors the Warburg phenotype. Transcriptional and post-transcriptional processes regulate the abundance and phosphorylation of PFKFB3 in cells, and its activation has been implicated in the progression of several types of cancer. PFKFB3 is important for sustaining glycolysis in the tumorigenesis environment even under unfavorable conditions, thereby promoting metabolic reprogramming, cell proliferation, DNA repair, and drug resistance. Despite its heterogeneous phenotype, breast cancer has unique characteristics that drive the constitutive and inducible expression of PFKFB3 in this opportunistic glycolytic shift. This enzyme is a point of convergence of multiple exogenous and endogenous growth-promoting and oncogenic signaling pathways, especially kinase cascades. The present review summarizes advances in in vitro and in vivo therapy studies that focus on PFKFB3 and the interplay between hormone receptor status and the underlying essential signal transduction system in breast cancer metabolic remodeling.