The Antiepileptic Drug Levetiracetam Inhibits Carbonic Anhydrase: <i>In Vitro</i> and <i>In Silico</i> Studies on Catalytically Active Human Isoforms

Several antiepileptic drugs (AEDs) have been found to inhibit human carbonic anhydrases (hCAs), paving the way for repurposing AEDs for the treatment of various diseases, including cancer. Here, the hCAs inhibitory effects of levetiracetam, a highly prescribed AED that does not bear a common zinc-binding group, were investigated <i>in vitro</i> and <i>in silico</i>. Levetiracetam inhibited all tested hCAs, although with a specific profile compared to the reference acetazolamide, with remarkable efficacy against tumor-associated hCA IX and XII. Molecular docking and dynamics (MD) simulations emphasized H-bonding to the Zn(II)-coordinated water as a major anchor point for hCAs, as well as a persistent interaction within the catalytic site of hCA isoforms IX and XII compared to II, which correlates with experimental data. Our results may explain why levetiracetam is also clinically effective as an antitumor agent in patients developing epilepsy as a consequence of brain tumors.