Sulfonamide Bioisosteres of Niclosamide Enhance Antibacterial Activity of Colistin and Bacitracin.

Multicomponent therapy combining antibiotics with enhancer molecules known as adjuvants is an emerging strategy to combat antimicrobial resistance. Niclosamide is a clinically relevant anthelmintic drug with potential to be repurposed for its inherent antibacterial activity against Gram-positive bacteria and its ability to potentiate the antibacterial activity of colistin against susceptible and resistant Gram-negative bacteria. Herein, sulfonamide analogs of niclosamide were prepared and found to enhance colistin activity against Gram-negative bacteria. The ability of niclosamide and the new sulfonamide analogs to synergize with bacitracin against vancomycin-resistant Enterococcus faecium was also discovered.

Discovery of N-substituted sulfamoylbenzamide derivatives as novel inhibitors of STAT3 signaling pathway based on Niclosamide.

Signal transducer and activator of transcription 3 (STAT3) has been confirmed as an attractive therapeutic target for cancer therapy. Herein, we designed and synthesized a series of N-substituted Sulfamoylbenzamide STAT3 inhibitors based on small-molecule STAT3 inhibitor Niclosamide. Compound B12, the best active compound of this series, was identified as an inhibitor of IL-6/STAT3 signaling with an IC50 of 0.61-1.11 µM in MDA-MB-231, HCT-116 and SW480 tumor cell lines with STAT3 overexpression, by inhibiting the phosphorylation of STAT3 of Tyr705 residue and the expression of STAT3 downstream genes, inducing apoptosis and inhibiting the migration of cancer cells. Furthermore, in vivo study revealed that compound B12 suppressed the MDA-MB-231 xenograft tumor growth in nude mice at the dose of 30 mg/kg (i.g.), which has better antitumor activity than the positive control Niclosamide. More importantly, B12 is an orally bioavailable anticancer agent as a promising candidate for further development.

Discovery of niclosamide and its O-alkylamino-tethered derivatives as potent antibacterial agents against carbapenemase-producing and/or colistin resistant Enterobacteriaceae isolates.

Carbapenemase-producing Enterobacteriaceae (CPE) represents the most worrisome evolution of the antibiotic resistance crisis, which is almost resistant to most of available antibiotics. This situation is getting even worse particularly due to the recent emergence of colistin resistance. Herein, niclosamide, an FDA-approved traditional drug, and its novel O-alkylamino-tethered derivatives were discovered as new and potent antibacterial agents against carbapenemase-producing and/or colistin resistant Enterobacteriaceae isolates. Among these molecules, compound 10 (HJC0431) with 4-aminobutyl moiety showed the broad antibacterial activities, effective against 6 strains. In vitro checkerboard and time-kill course studies demonstrated the synergistic effects of the screened compounds with colistin against the corresponding strains with various degrees.

Formulation and evaluation of cyclodextrin complexes for improved anticancer activity of repurposed drug: Niclosamide.

Niclosamide, previously used as an anthelmintic drug is currently being repurposed for its anticancer activity. Niclosamide is a brick like biopharmaceutical classification system (BCS) class II drug with poor aqueous solubility and dissolution consequently leading to low bioavailability. By considering the physicochemical properties and geometry of niclosamide, inclusion complex with cyclodextrin was prepared by freeze drying method and characterized using FT-IR, DSC, PXRD, and 1HNMR. In silico molecular modeling study was performed to study the possible interactions between niclosamide and cyclodextrin. The anticancer activity of niclosamide formulation was evaluated through in vitro cell cytotoxicity study using various cancer cell lines. The potential of niclosamide complex for improvement of the bioavailability was evaluated in male BALB/c mice. In vitro cytotoxicity studies indicated significantly higher cytotoxicity at lower concentrations and the pharmacokinetic studies showed significant improvement in Cmax and Tmax of niclosamide from cyclodextrin complex in comparison to pure niclosamide alone.

Identification of novel triazole inhibitors of Wnt/ß-catenin signaling based on the Niclosamide chemotype.

Dysregulation of the Wnt signaling pathway is an underlying mechanism in multiple diseases, particularly in cancer. Until recently, identifying agents that target this pathway has been difficult and as a result, no approved drugs exist that specifically target this pathway. We reported previously that the anthelmintic drug Niclosamide inhibits the Wnt/ß-catenin signaling pathway and suppresses colorectal cancer cell growth in vitro and in vivo. In an effort to build on this finding, we sought to discover new Wnt/ß-catenin inhibitors that expanded the chemotype structural diversity. Here, we asked a specific SAR question unresolved in previous SAR studies of Niclosamide's inhibition of Wnt/ß-catenin signaling to identify a new structural class of Wnt/ß-catenin signaling inhibitors based on a triazole motif. Similar to Niclosamide, we found that the new triazole derivatives internalized Frizzled-1 GFP receptors, inhibited Wnt/ß-catenin signaling in the TOPflash assay and reduced Wnt/ß-catenin target gene levels in CRC cells harboring mutations in the Wnt pathway. Moreover, in pilot SAR studies, we found the Wnt/ß-catenin SAR trends in the anilide region were generally similar between the two chemical classes of inhibitors. Overall, these studies demonstrate the ability to use the SAR of the Niclosamide salicylanilide chemical class to expand the structural diversity of Wnt/ß-catenin inhibitors.

Synthesis and orally macrofilaricidal evaluation of niclosamide lymphotropic prodrugs.

The development of new macrofilaricidal drugs is described following a strategy for the promotion of the lymphatic transport of anthelminthic drugs by-passing the liver. The selected compound was niclosamide (CAS 50-65-7) which is very effective in vitro against infective larvae but has no significant antifilarial activity when orally administered at 200 mumol/kg. To estimate the interest of such an approach, the synthesis of 5 prodrugs was achieved in a first stage. The intrinsic antifilarial activity and the delayed effect of these compounds were evaluated in vitro. Then, in vivo tests were performed with Molinema dessetae infective larvae to select the best ligands. The prodrug V 1,3-dihexadecanamido-2-[4-chloro(2- chloro-4-nitroanilinocarbonyl)phenyloxy-carbonylpropanoyl oxy]propane (having a diamide function) was responsible for an in vitro delayed effect and an orally in vivo activity (200 mumol/kg when administered in a single dose). The biological improvement of this easily micellizable prodrug which is stable to intestinal enzymes in respect to Niclosamide confirms such a strategy.