Background Nitroxoline is an antibiotic widely used in several countries from 1960s known to act by chelating divalent metal ions such as Mg2+ and Mn2+. In a recent study, we analysed the effects of nitroxoline as a candidate for repurposing in pancreatic cancer cells (AsPC-1), showing that the drug has antitumor effects comparable to erlotinib, a drug approved for PC treatment.
Methods. In the present study, by exploiting a label-free shotgun proteomics approach, we analysed the effect of nitroxoline on the protein repertoire of AsPC-1 cells after 24 and 48 hours of treatment.
Results The label-free shotgun proteomics analysis resulted in the detection of 81 proteins consistently deregulated at both timepoints. Those protein were subjected to a few bioinformatic analyses including STRING and IPA. STRING analysis showed that many of the proteins are connected in a single network, with a highly significant protein-protein interaction enrichment (p-value < 10-16). The highest enriched pathways, as showed by IPA analysis, are related to some of the pathways known to be modulated by nitroxoline such as mTOR and sirtuins. Among the additional highest ranked pathways several were related to metabolism including Krebs cycle and aminoacid, lipid and carbohydrate metabolism. The level of expression of ATP1B3, β-catenin and TFR1 were confirmed by western blot. Our results suggest that Na/K-ATPase downregulation could to be linked to several antitumor actions of nitroxoline, including inhibition of the PI3K/AKT/GSK3β/β-catenin pathway, induction of oxidative stress and triggering of DNA damage response.
Conclusions With the present study we identified target pathways previously unknown to be affected by Nitroxoline.Our results indicate that Nitroxoline treatment impairs cell migration and invasion, increases intracellular ROS and activates oxidative DNA damage response, reduces cotranslational protein targeting to membrane and increases lactate production.