Rationally repurposed nitroxoline inhibits preclinical models of Epstein-Barr virus-associated lymphoproliferation

A quality-by-design evaluated liquid chromatography method development and validation for the separation and quantification of nitroxoline and its impurities

A novel, isocratic, sensitive, stability-indicating high-performance liquid chromatography method was developed for the separation and quantification of related substances in nitroxoline (NTL). The chromatographic separation has been achieved on Inertsil ODS-3 V, (250 × 4.6 mm, 5 μm) at 240 nm using ethylenediamine tetraacetic acid buffer and methanol in the ratio of 60:40 v/v as mobile phase. The performance of the method has been checked as per the International Conference on Harmonization guidelines for specificity, linearity, accuracy, precision, and robustness. Regression analysis showed a correlation coefficient value greater than 0.99 for NTL and its three impurities. The detection limit of impurities was in the range of 0.01% (0.05 μg/mL)-0.22% (1.1 μg/mL) indicating the sensitivity of the newly developed method. The accuracy of the method was established based on the recovery obtained between 94.7% and 104.1% for all the impurities. The percentage relative standard deviation obtained for the repeatability was less than 4.0% at the specification level for all impurities. Forced degradation was performed to establish the stability-indicating nature of the method and to know about the degradation products, the quality of a drug substance changes with time under the influence of stress conditions. Thus, the proposed method was validated and found to be specific, sensitive, linear, accurate, precise, reproducible, and beneficial for routine usage.

Nitroxoline suppresses metastasis in bladder cancer via EGR1/circNDRG1/miR-520h/smad7/EMT signaling pathway

Bladder cancer is one of the most common and deadly cancer worldwide. Current chemotherapy has shown limited efficacy in improving outcomes for patients. Nitroxoline, an old and widely used oral antibiotic, which was known to treat for urinary tract infection for decades. Recent studies suggested that nitroxoline suppressed the tumor progression and metastasis, especially in bladder cancer. However, the underlying mechanism for anti-tumor activity of nitroxoline remains unclear.

Methods: CircRNA microarray was used to explore the nitroxoline-mediated circRNA expression profile of bladder cancer lines. Transwell and wound-healing assay were applied to evaluate the capacity of metastasis. ChIP assay was chosen to prove the binding of promotor and transcription factor. RNA-pulldown assay was performed to explore the sponge of circRNA and microRNA.

Results: We first identified the circNDRG1 (has_circ_0085656) as a novel candidate circRNA. Transwell and wound-healing assay demonstrated that circNDRG1 inhibited the metastasis of bladder cancer. ChIP assay showed that circNDRG1 was regulated by the transcription factor EGR1 by binding the promotor of host gene NDRG1. RNA-pulldown assay proved that circNDRG1 sponged miR-520h leading to the overexpression of smad7, which was a negative regulatory protein of EMT.

Conclusions: Our research revealed that nitroxoline may suppress metastasis in bladder cancer via EGR1/circNDRG1/miR-520h/smad7/EMT signaling pathway.

Chelation in Antibacterial Drugs: From Nitroxoline to Cefiderocol and Beyond

In the era of escalating antimicrobial resistance, the need for antibacterial drugs with novel or improved modes of action (MOAs) is a health concern of utmost importance. Adding or improving the chelating abilities of existing drugs or finding new, nature-inspired chelating agents seems to be one of the major ways to ensure progress. This review article provides insight into the modes of action of antibacterial agents, class by class, through the perspective of chelation. We covered a wide scope of antibacterials, from a century-old quintessential chelating agent nitroxoline, currently unearthed due to its newly discovered anticancer and antibiofilm activities, over the commonly used antibacterial classes, to new cephalosporin cefiderocol and a potential future class of tetramates. We show the impressive spectrum of roles that chelation plays in antibacterial MOAs. This, by itself, demonstrates the importance of understanding the fundamental chemistry behind such complex processes.