Chloroxine inhibits pancreatic cancer progression through targeted antagonization of the PI3K/AKT/mTOR signaling pathway / La cloroxina inhibe la progresión del cáncer de páncreas mediante la antagonización dirigida de la vía de señalización PI3K/AKT/mTOR

Background: Patients with pancreatic cancer have a dismal prognosis due to tumor cell infiltration and metastasis. Many reports have documented that EMT and PI3K–AKT–mTOR axis control pancreatic cancer cell infiltration and metastasis. Chloroxine is an artificially synthesized antibacterial compound that demonstrated anti-pancreatic cancer effects in our previous drug-screening trial. We have explored the impact of chloroxine on pancreatic cancer growth, infiltration, migration, and apoptosis. Methods: The proliferation of pancreatic cancer cell lines (PCCs) treated with chloroxine was assessed through real-time cell analysis (RTCA), colony formation assay, CCK-8 assay, as well as immunofluorescence. Chloroxine effects on the infiltrative and migratory capacities of PCCs were assessed via Transwell invasion and scratch experiments. To assess the contents of EMT- and apoptosis-associated proteins in tumor cells, we adopted Western immunoblotting as well as immunofluorescence assays, and flow cytometry to determine chloroxine effects on PCCs apoptosis. The in vivo chloroxine antineoplastic effects were explored in nude mice xenografts. Results: Chloroxine repressed pancreatic cancer cell growth, migration, and infiltration in vitro, as well as in vivo, and stimulated apoptosis of the PCCs. Chloroxine appeared to inhibit PCC growth by Ki67 downregulation; this targeted and inhibited aberrant stimulation of the PI3K–AKT–mTOR signaling cascade, triggered apoptosis in PCC via mitochondria-dependent apoptosis, and modulated the EMT to inhibit PCC infiltration and migration. Conclusions: Chloroxine targeted and inhibited the PI3K–AKT–mTOR cascade to repress PCCs growth, migration, as well as invasion, and triggered cellular apoptosis. Therefore, chloroxine may constitute a potential antineoplastic drug for the treatment of pancreatic cancer.(AU)

A simple, sensitive and reliable LC-MS/MS method for the determination of 7-bromo-5-chloroquinolin-8-ol (CLBQ14), a potent and selective inhibitor of methionine aminopeptidases: Application to pharmacokinetic studies.

CLBQ14 is an 8-hydroxyquinoline analogue that inhibits methionine aminopeptidase (MetAP), an enzyme responsible for the post-translational modification of several proteins and polypeptides. MetAP has been validated as druggable target for some infectious diseases, and its inhibitors have been investigated as potential therapeutic agents. In this study, we developed and validated a liquid chromatography tandem-mass spectrometry (LC-MS/MS) method for the quantification of CLBQ14 in solution, and in rat plasma and urine. This method was applied to the pharmacokinetic evaluation of CLBQ14 in adult male Sprague Dawley (SD) rats. Chromatographic separation was achieved using an ultra-high-performance liquid chromatography (UHPLC) system equipped with Waters XTerra MS C18 column (3.5 µm, 125 Å, 2.1 × 50 mm) using 0.1% formic acid in acetonitrile/water gradient system as mobile phase. Chromatographic analysis was performed with a 4000 QTRAP® mass spectrometer using MRM in positive mode for CLBQ14 transition [M + H]+m/z 257.919 → m/z 151.005, and IS (clioquinol) transition [M + H]+m/z 305.783 → m/z 178.917. CLBQ14 was extracted from plasma and urine samples by protein precipitation. The retention times for CLBQ14 and IS were 1.31 and 1.40 min respectively. The standard curves were linear for CLBQ14 concentration ranging from 1 to 1000 ng/mL. The intra-day and inter-day accuracy and precision were found to be within 15% of the nominal concentration. Extraction recoveries were >96.3% and 96.6% from rat plasma and urine respectively, and there was no significant matrix effect from the biological matrices. CLBQ14 is stable in samples subjected to expected storage, preparation, and handling conditions. Pharmacokinetic studies revealed that CLBQ14 has a bi-exponential disposition in SD rats, is extensively distributed with a long plasma half-life and is eliminated primarily by liver metabolism.