The cytotoxicity production was markedly decreased with addition of ZnCl2, indicating, based on this model, that nitroxoline is not a zinc chelator.

[4] Cathepsin B degrades extra-cellular membrane proteins in tumor cells, allowing them to proliferate more freely, and metastasize throughout the body.

In fact, it was recently shown that a balance exists between the potency and the kinetics of a molecule, reflected in the molecular weight, which must be optimized in order to create the best drug for inhibition of a target enzyme.

In 2018, nitroxoline was identified via a clinical metagenomic next-generation sequencing analysis as a compound that could be repurposed as an amoebicidal agent against Balamuthia mandrillaris which causes the fatal disease granulomatous amoebic encephalitis (GAE).

[9][10] The man had been given the recommended drug therapy of pentamidine, sulfadiazine, azithromycin, fluconazole, flucytosine, and miltefosine but progressed negatively.