YN1 is a potent inhibitor of PFKFB3 (6-Phosphfructo-2-kinase/fructose-2,6-bisphosphatase: IC50 = 670 nM). PFKFB3 is over expressed in many cancers, and catalyzes the production of fructose-2,6-bisphosphate, which can potentiate PFK1 activity, enhancing glycolysis in tumor cells. YN1 inhibits glycolysis and proliferation in HeLa cells.