Schumacher, T. J. | Search bioRxiv

bioRxiv2025

Nitroxoline-O-protected derivatives inhibit MetAP2 and activate ATF4 through mTORC1 to inhibit cancer cell growth

Reprogrammed cancer cell proliferation requires high levels of protein synthesis and concomitant folding and processing. N-terminal methionine amino peptidases (MetAP) are a class of enzymes that cleave the initiator methionine amino acids to allow for peptide maturation and co-translational processing. Specifically, based on its role in protein synthesis, MetAP2 has been found to be upregulated in cancer cells and has been explored as a potential anticancer target. Cellular perturbations that impinge on protein synthesis activate cellular stress pathways, including the integrated stress response and mTORC1. Nitroxoline, a MetAP2 inhibitor has been explored as an anticancer agent but is hampered by poor pharmacokinetic properties. Here, we synthesize a few O-substituted silyl and nonsilyl nitroxoline analogs to diversify the nitroxoline template to reduce metabolic vulnerability. In vitro MetAP2 and cancer cell proliferation inhibition assays demonstrate that synthesized analogs retain potency when compared to the parent nitroxoline. Mechanistically, we show that the lead candidate compound 3 and nitroxoline activate ATF4 mediated stress responses through non-canonical mTORC1. These results further implicate MetAP2 protein processing in mTORC1 nutrient sensing pathways and provide novel synthetic analogs of nitroxoline for potential cancer treatment.

cancer biology↗

bioRxiv2024

Repurposing mitochondrial-targeting anthelmintic agents with GLUT1 inhibitor BAY-876 for cancer therapy

Cancer cells alter their metabolic phenotypes with nutritional change. Single agent approaches targeting mitochondrial metabolism in cancer have failed due to either dose limiting off target toxicities, or lack of efficacy in vivo. To mitigate these clinical challenges, we investigated the potential utility of repurposing FDA approved mitochondrial targeting anthelmintic agents, niclosamide and pyrvinium pamoate, to be combined with GLUT1 inhibitor BAY-876 to enhance the inhibitory capacity of the major metabolic phenotypes exhibited by tumors. To test this, we used breast cancer cell lines MDA-MB-231 and 4T1 which exhibit differing basal metabolic rates of glycolysis and mitochondrial respiration, respectively. Here, we found that specific responses to mitochondrial and glycolysis targeting agents elicit responses that correlate with tested cell lines basal metabolic rates and fuel preference, highlighting the potential to cater metabolism targeting treatment regimens based on specific tumor nutrient handling. Inhibition of GLUT1 with BAY-876 potently inhibited glycolysis in both MDA-MB-231 and 4T1 cells, and niclosamide and pyrvinium pamoate perturbed mitochondrial respiration that resulted in potent compensatory glycolysis in the cell lines tested. In this regard, combination of BAY-876 with both mitochondrial targeting agents resulted in inhibition of compensatory glycolysis and subsequent metabolic crisis. These studies warrant further investigation into targeting tumor metabolism as a combination treatment regimen that can be tailored by basal and compensatory metabolic phenotypes.

cancer biology↗