Polyoxometalates – a new class of potent ecto-nucleoside triphosphate diphosphohydrolase (NTPDase) inhibitors

Polyoxotungstates were identified as potent inhibitors of NTPDases1, 2, and 3. The most potent compound was K₆H₂[TiW₁₁CoO₄₀], exhibiting K_i values of 0.140 µM (NTPDase1), 0.910 µM (NTPDase2), and 0.563 µM (NTPDase3). One of the compounds, (NH₄)₁₈[NaSb₉W₂₁O₈₆], was selective for NTPDases2 and 3 versus NTPDase1. NTPDase inhibition might contribute to the described biological effects of polyoxometalates, including their anti-cancer activity.