Bisphosphonate Inhibitors of Mammalian Glycolytic Aldolase

The
glycolytic enzyme aldolase is an emerging drug target in diseases
such as cancer and protozoan infections which are dependent on a hyperglycolytic
phenotype to synthesize adenosine 5′-triphosphate and metabolic
precursors for biomass production. To date, structural information
for the enzyme in complex with phosphate-derived inhibitors has been
lacking. Thus, we determined the crystal structure of mammalian aldolase
in complex with naphthalene 2,6-bisphosphate (1) that
served as a template for the design of bisphosphonate-based inhibitors,
namely, 2-phosphate-naphthalene 6-bisphosphonate (2),
2-naphthol 6-bisphosphonate (3), and 1-phosphate-benzene
4-bisphosphonate (4). All inhibitors targeted the active
site, and the most promising lead, 2, exhibited slow-binding
inhibition with an overall inhibition constant of ∼38 nM. Compound 2 inhibited proliferation of HeLa cancer cells, whereas HEK293
cells expressing a normal phenotype were not inhibited. The crystal
structures delineated the essential features of high-affinity phosphate-derived
inhibitors and provide a template for the development of inhibitors
with prophylaxis potential.