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Cerebral ischemia is one of the major causes of death and disability worldwide. Currently, existing approved therapies are based on reperfusion and there is an unmet need to search for drugs with neuroprotective effects. The present study aims to investigate the neuroprotective mechanisms of nitroxoline, a nitro derivative of 8-Hydroxyquinoline, against cerebral ischemia using integrated network pharmacology and molecular docking approaches. Critical analytical tools used were SwissTarget, PharmMapper, BindingDB, DisGeNet, Cytoscape, GeneMANIA, ShinyGo, Metascape, GeneCodis, and Schrodinger GLIDE. Thirty-six overlapping drug and disease targets were identified and used for further analysis. Gene Ontology results showed that nitroxoline enriched the genes involved in biological processes of oxidative stress and apoptotic cell death that are highly implicated in hypoxic injury. KEGG enrichment analysis showed nitroxoline influenced a total of 159 biological pathways, out of which, top pathways involved in cerebral ischemia included longevity regulating pathway, VEGF signaling, EGFR tyrosine kinase inhibitor resistance, IL-17 and HIF-1 pathways, FoxO signaling, and AGE-RAGE pathway. Protein–protein interaction analysis using string database showed PARP1, EGFR, PTEN, BRD4, RAC1, NOS2, MTOR, MAPK3, BCL2, MAPK1, APP, METAP2, MAPK14, SIRT1, PRKAA1, and MCL1 as highly interactive proteins involved in pathogenesis of ischemic stroke regulated by nitroxoline. The highly interactive protein targets were validated by molecular docking studies and molecular dynamic simulations. Amongst all these targets, nitroxoline showed the highest binding affinity towards BRD4 followed by PARP1 and PTEN. Nitroxoline, through network pharmacology analysis, showed a role in regulating proteins, biological processes, and pathways crucial in cerebral ischemia. The current study thus provides a preliminary insight that nitroxoline might be used as a neuroprotectant against cerebral ischemia via modulating the epigenetic reader BRD4 and transcription factors such as RELA, NF-κβ1, and SP1. However, further in-vitro and preclinical studies need to be performed for concrete evidence.

In this work, an azo dye ligand of 2,6-dichloroaniline with nitroxoline ( CPAQ ), and its Zn(II), Cu(II), Cd(II), Ni(II) and Co(II) complexes have been synthesized. The structures of the synthesized compounds have been elucidated applying analytical and spectral tools. According to these results, all complexes proved to have a tetrahedral structure, except Ni(II) complex, which has an octahedral geometry. Analytical results also inferred the formation of Co(II) and Ni(II) complexes in the molar ratio 1M:1L and the remaining complexes in 1M:2L molar ratio. For further insight into the complexes’ geometry, bond lengths, bond angles, and electronic characteristics with respect to the organic ligand were assigned in addition to DFT calculations. HOMO and LOMO calculations show the Co(II) complex is more reactive. The interactions of the target compounds with the Mus musculus ADA enzyme structure (PDB ID: 1a4m) were estimated by applying molecular docking studies. The inhibitory effect of the synthesized compounds on adenosine deaminase enzyme (ADA) activity was tested in-vitro, showing the Co(II) to be the most active.

A significant amount of data about the different pharmacological activities of the established antimicrobial compound nitroxoline (8-hydroxy-5-nitroquinoline) is available in the scientific literature. On the other hand, its regioisomer 8-hydroxy-6-nitroquinoline was never characterised biochemically and the same also applies to their 1,2,3,4-tetrahydroquinoline analogues. Herein, we determined the influence of pyridine ring saturation and the position of the nitro group on various biochemical characteristics of compounds, such as metal-chelating properties, inhibition of methionine aminopeptidases (MetAPs) from and human MetAP2, as well as antibacterial activities on , , and . In addition, inhibition of endopeptidase and exopeptidase activities of cathepsin B was determined, together with the ability of new nitroxo-line analogues to reduce intracellular collagen IV degradation. Substantially different biological activities were observed for the 6-nitro regioisomer of nitroxoline, as well as for both of their partially saturated counterparts.

Repurposing of currently used drugs for new indications benefits from known experience with those agents. Rational repurposing can be achieved when newly uncovered molecular activities are leveraged against diseases that utilize those mechanisms. Nitroxoline is an antibiotic with metal-chelating activity used to treat urinary tract infections. This small molecule also inhibits the function of bromodomain and extraterminal (BET) proteins that regulate oncogene expression in cancer. Lymphoproliferation driven by the Epstein–Barr virus (EBV) depends on these same proteins. We therefore tested the efficacy of nitroxoline against cell culture and small animal models of EBV-associated lymphoproliferation. Nitroxoline indeed reduces cell and tumor growth. Nitroxoline also acts faster than the prototype BET inhibitor JQ1. We suggest that this rational repurposing may hold translational promise.

Pancreatic cancer (PC) is one of the deadliest carcinomas and in most cases, which are diagnosed with locally advanced or metastatic disease, current therapeutic options are highly unsatisfactory. Based on the anti-proliferative effects shown by nitroxoline, an old urinary antibacterial agent, we explored a large library of newly synthesised derivatives to unravel the importance of the OH moiety and pyridine ring of the parent compound. The new derivatives showed a valuable anti-proliferative effect and some displayed a greater effect as compared to nitroxoline against three pancreatic cancer cell lines with different genetic profiles. In particular, in silico pharmacokinetic data, clonogenicity assays and selectivity indexes of the most promising compounds showed several advantages for such derivatives, as compared to nitroxoline. Moreover, some of these novel compounds had stronger effects on cell viability and/or clonogenic capacity in PC cells as compared to erlotinib, a targeted agent approved for PC treatment.

The synthesis of helical aromatic oligoamide foldamers derived from 8-amino-2-quinolinecarboxylic acid is described. The precursors are commercially available and products up to and including the octamer are obtained. The procedure covers the synthesis of the monomer, reduction of N-terminal nitro groups into amines, saponification of C-terminal methyl esters to form carboxylic acids, and coupling of amines and acids to form amides via acid chloride activation. Emphasis is given to how these reactions can be scaled up and how purification can be greatly simplified using recrystallization methods, thus providing considerable improvements over previously described procedures. As an illustration of the improvement, 8.4 g of an octamer can now reliably be prepared from a nitro-ester monomer in a matter of 8 (working) weeks without any chromatography.

Fork head box M1 (FoxM1) is an oncogenic transcription factor frequently elevated in numerous cancers, including cholangiocarcinoma (CCA). A growing body of evidence documents its diverse functions contributing to tumorigenesis and cancer progression. As such, discovery of agents that can target FoxM1 would be valuable for the treatment of CCA. The quinoline-based compounds, namely clioquinol (CQ) and nitroxoline (NQ), represent a new class of anticancer drug. However, their efficacy and underlying mechanisms have not been elucidated in CCA. In this study, anticancer activities and inhibitory effects of CQ and NQ on FoxM1 signaling were explored using CCA cells. The effects of CQ and NQ on cell viability and proliferation were evaluated using the colorimetric 3-(4,5-dimethylthiazol-2yl)-5-(3-carboxymethoxyphenyl)-(4-sulfophenyl)-2H-tetrazolium (MTS assay). Colony formation and cell migration affected by CQ and NQ were investigated using a clonogenic and a wound healing assay, respectively. To demonstrate the agents' effects on FoxM1 signaling, expression levels of the target genes were quantitatively determined using real-time polymerase chain reaction. CQ and NQ significantly inhibited cell survival of HuCCT1 and Huh28 in a dose- and a time-dependent fashion. Further investigations using the rapidly proliferating HuCCT1 cells revealed significant suppression of cell proliferation and colony formation induced by low doses of the compounds. Treatment of CQ and NQ repressed expression of cyclin D1 but enhanced expression of p21. Most importantly, upon CQ and NQ treatment, expression of oncogenic FoxM1 was markedly decreased concomitant with downregulation of various FoxM1's downstream targets including cdc25b, CENP-B, and survivin. In addition, the compounds distinctly impaired HuCCT1 migration as well as inhibited expression of matrix metalloproteinase (MMP)-2 and MMP-9. Collectively, this study reports for the first time the anticancer effects of CQ and NQ against CCA cells, and highlights new insights into the mechanism of actions of the quinoline-based compounds to disrupt FoxM1 signaling.

The proto‐oncogene MDM2 is a nuclear‐localized E3 ubiquitin ligase, which promotes tumor formation by targeting tumor suppressor proteins, such as p53, for proteasomal degradation. In this study, the anti‐infective drug nitroxoline (NXQ) was screened out to effectively inhibit cell survival of small‐cell lung cancer (SCLC) cells, and induce SCLC cell apoptosis by suppressing antiapoptotic proteins (such as Bcl‐2 and MCL1) and upregulating proapoptotic protein Bim. In the mechanistic study, NXQ was found to downregulate MDM2 expression by inducing its proteasomal degradation, and thus upregulated p53 expression, which was a substrate protein of MDM2. Moreover, overexpression of MDM2 decreased the cytotoxicity of NXQ on SCLC cells. These results demonstrated that NXQ displayed anti‐SCLC activity by suppressing MDM2 expression, which suggested that anti‐infective NXQ had potential for SCLC treatment by targeting the MDM2/p53 axis.

Aim: To design and synthesize a novel class of antitumor agents, featuring the 3-nitroquinoline framework. Methods: Based on the enzyme-binding features of Ekb1, introducing a nitro group at the 3-position of the quinoline core, a series of novel 3-nitroquinolines was designed and synthesized. The inhibition of epidermal growth factor receptor (EGFR) activity by these compounds was evaluated and analyzed by the sulforhodamine B assay for their inhibitory activities toward human epidermoid carcinoma (A431) cells and breast cancer (MDA-MB-468) cells, which are known to overexpress the EGFR kinase. Results: A series of novel 3-nitroquinoline derivatives were synthesized and evaluated for their antiproliferative effect against the EGFR-overexpressing tumor cell lines. Several compounds for concentration-response studies showed prominent inhibitory activities with IC 50 values in the micromolar or nanomolar range. The structure-activity relationship was discussed in terms of the inhibitory activity against the proliferation of 2 human carcinoma cell lines. Conclusion: This study was the first to identify new structural types of antiproliferative agents against the EGFR-overexpressing tumor cell lines by the incorporation of the nitro group at the 3-position of the quinoline core structure, providing promising new templates for the further development of anticancer agents.

Clioquinol and nitroxoline, two drugs with numerous pharmacological properties fallen into disuse for many decades. The first was considered dangerous due to contraindications and the second mainly because was taken as ineffective, despite its known antibacterial activity. In the last decades, the advances in pharmaceutical chemistry, molecular biology, toxicology and genetics allowed to better understand the cellular action of these compounds, some toxicological issues and/or activity scopes. Thus, a new opportunity for these drugs to be considered as potential antimicrobial agents has arisen. This review contemplates the trajectory of clioquinol and nitroxoline from their emergence to the present day, emphasizing the new studies that indicate the possibility of reintroduction for specific cases.