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 Ki 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.