A dual-action niclosamide-based prodrug that targets cancer stem cells and inhibits TNBC metastasis

Chemotherapy typically destroys the tumor mass but rarely eradicates the cancer stem cells (CSCs) that can drive metastatic recurrence. A key current challenge is finding ways to eradicate CSCs and suppress their characteristics. Here, we report a prodrug, Nic-A, created by combining a carbonic anhydrase IX (CAIX) inhibitor, acetazolamide, with a signal transducer and transcriptional activator 3 (STAT3) inhibitor, niclosamide. Nic-A was designed to target triple-negative breast cancer (TNBC) CSCs and was found to inhibit both proliferating TNBC cells and CSCs via STAT3 dysregulation and suppression of CSC-like properties. Its use leads to a decrease in aldehyde dehydrogenase 1 activity, CD44high/CD24low stem-like subpopulations, and tumor spheroid-forming ability. TNBC xenograft tumors treated with Nic-A exhibited decreased angiogenesis and tumor growth, as well as decreased Ki-67 expression and increased apoptosis. In addition, distant metastases were suppressed in TNBC allografts derived from a CSC-enriched population. This study thus highlights a potential strategy for addressing CSC-based cancer recurrence.

Niclosamide causes lysosome-dependent cell death in endometrial cancer cells and tumors

Endometrial cancer is the most common female cancer showing continuous rise in its incidence and mortality rate. Despite the extensive research efforts in cancer therapeutics, still there is a lack of effective treatment options and the outcome is poor for patients with advanced and recurrent endometrial cancers. In this study, we aimed to evaluate the efficacy of niclosamide (NIC) against endometrial cancer. NIC is an FDA-approved anti-helminthic drug, which has been recently extensively studied as a potent anti-cancerous agent in several cancers. The anti-cancerous activity of NIC was analyzed in-vitro (ANC3A, Hec1B, and Ishikawa endometrial cancer cell lines) by cell viability-, soft agar-, invasion- and migration- assay. The action mechanism of NIC was demonstrated by western blot analysis and immune-fluorescence imaging and validated by specific inhibitors. The in-vivo efficacy of NIC was studied in the Ishikawa xenograft animal model. NIC effectively suppressed the viability (IC50<1 μM), colony formation ability, migration, and invasion of all endometrial cancer cells tested. We demonstrated that NIC inhibited AKT/mTOR signaling pathway and induced apoptosis and autophagy in endometrial cancer cells. Further study demonstrated that although NIC induced autophagosome formation, it inhibits autolysosome formation. In addition, we observed that NIC induced BAX co-localization with lysosome and inhibited Cathepsin B maturation from pro-cathepsin B, thereby inducing the lysosomal membrane permeability and release of hydrolytic enzymes from the lysosome to cytosol, which eventually contributed cell death. NIC also inhibited tumor weight and volume in the Ishikawa xenograft animal model without having any evidence of toxicity. Due to its potent anti-cancerous activity and safety profile, NIC seems to be a promising agent for human endometrial cancer therapeutics.

Niclosamide modulates cyclosporin A-induced hepatotoxicity in a mouse model: PPAR-γ and Wnt/β-catenin crosstalk

OBJECTIVES

The aim of this study was to evaluate whether: 1) Wnt/β-catenin signaling is involved in cyclosporin A (CsA)-induced hepatotoxicity, and 2) knockdown of this pathway by niclosamide (NCL) attenuate CsA-induced hepatotoxicity.

METHODS

The experiment was accomplished in 21 days. Adult male mice were randomly distributed into five groups: control group, CsA (25 mg/kg/day) group, CsA + NCL (2.5 mg/kg/day) group, CsA + NCL (5 mg/kg/day) group, and NCL (5 mg/kg/day) group.

RESULTS

NCL showed marked hepatoprotection by significantly decreasing liver enzymes activities and ameliorating the histopathological alterations induced by CsA. Besides, NCL alleviated oxidative stress and inflammation. NCL-treated groups (2.5 and 5 mg/kg) displayed rise in the expression of hepatic peroxisome proliferator-activated receptor-γ (PPAR-γ) by 2.1- and 2.5-fold, respectively. Notably, NCL (2.5 and 5 mg/kg) significantly inhibited Wnt/β-catenin signaling, evidenced by a marked decrease in the hepatic expression of Wnt3a by 54 % and 50 %, frizzled-7 receptor by 50 % and 50 %, β-catenin by 22 % and 49 %, and c-myc by 50 % and 50 %, respectively.

CONCLUSIONS

NCL can be regarded as a potential agent to mitigate CsA-induced hepatotoxicity.

Salicylanilides and Their Anticancer Properties

Salicylanilides are pharmacologically active compounds with a wide spectrum of biological effects. Halogenated salicylanilides, which have been used for decades in human and veterinary medicine as anthelmintics, have recently emerged as candidates for drug repurposing in oncology. The most prominent example of salicylanilide anthelmintic, that is intensively studied for its potential anticancer properties, is niclosamide. Nevertheless, recent studies have discovered extensive anticancer potential in a number of other salicylanilides. This potential of their anticancer action is mediated most likely by diverse mechanisms of action such as uncoupling of oxidative phosphorylation, inhibition of protein tyrosine kinase epidermal growth factor receptor, modulation of different signaling pathways as Wnt/β-catenin, mTORC1, STAT3, NF-κB and Notch signaling pathways or induction of B-Raf V600E inhibition. Here we provide a comprehensive overview of the current knowledge about the proposed mechanisms of action of anticancer activity of salicylanilides based on preclinical in vitro and in vivo studies, or structural requirements for such an activity.

Niclosamide as a Promising Therapeutic Player in Human Cancer and Other Diseases

Niclosamide is an FDA-approved anthelmintic drug for the treatment of parasitic infections. However, over the past few years, increasing evidence has shown that niclosamide could treat diseases beyond parasitic diseases, which include metabolic diseases, immune system diseases, bacterial and viral infections, asthma, arterial constriction, myopia, and cancer. Therefore, we systematically reviewed the pharmacological activities and therapeutic prospects of niclosamide in human disease and cancer and summarized the related molecular mechanisms and signaling pathways, indicating that niclosamide is a promising therapeutic player in various human diseases, including cancer.

Niclosamide Modulates the Cellular and Humoral Immune Response in Balb/c Mice

BACKGROUND

Niclosamide, a STAT3 inhibitor, is widely under investigation due to its anti-cancer properties. STAT3 also exhibits an exciting role in the immune responses.

OBJECTIVE

This study aimed to evaluate the impact of niclosamide on immune response of mice.

METHODS

Niclosamide was administered to balb/c mice. To evaluate cell-mediated immune response, a contact-hypersensitivity (CHS) test, cyclophosphamide-induced neutropenic assay, and carbon clearance test were performed, whereas a humoral immune response was evaluated by hemagglutination assay (HA) and mice lethality test. The concentration of TGF-β1 was determined by enzyme-linked immunosorbent assay (ELISA) on murine peritoneal macrophages.

RESULTS

In the CHS test, niclosamide caused a decrease in skin thickness, significantly exhibiting a decrease in inflammation. A highly significant decrease in overall leukocyte count (lymphocytes and neutrophils) was observed before and after cyclophosphamide injection as compared with the control group. However, only a highly significant decrease in the neutrophil percentage was observed. Niclosamide has decreased the phagocytic process immensely compared with the control. In the HA titer, niclosamide was found to reduce the antibodies' titer compared with the negative control group. In the mice lethality test, the treatment groups have shown an increase in the percentage of mortality. TGF-β1 elevated in peritoneal macrophages when treated with niclosamide, in a dose-dependent manner.

CONCLUSION

Niclosamide exerts potent immunomodulatory effects by significantly suppressing cell-mediated and humoral immune responses and increasing the levels of TGF-β1 in mice. Niclosamide might be added as an adjuvant to immunosuppressive drugs for the treatment of autoimmune diseases.

Study on the Synergistic Molluscicidal Effect of Pedunsaponin A and Niclosamide

Niclosamide (NI) is the main molluscicide used to control Pomacea canaliculata (Lamarck) (Architaenioglossa: Ampullariidae). However, NI failed to inhibit snail climbing during the treatment process. In this study, we examined the effect of NI combined with pedunsaponin A at an ineffective concentration. The molluscicidal effect of Pedunsaponin A on NI was evidently synergistic after 48 h, and the synergism ratio (SR) was 1.82 after treatment for 72 h at 0.8 mg·L^-1. Examination of the climbing adhesion effect showed that a high concentration of Pedunsaponin A (0.4 mg·L^-1 and 0.8 mg·L^-1) combined with NI significantly inhibited the climbing of P. canaliculata. We further studied the synergism mechanism; the results of histopathological observation showed that the siphon appeared cavities, the muscle fibers of the ventricular were severely dissolved, and kidney tubule arrangement was distorted after NI adding Pedunsaponin A. In addition, the hemocyte survival rate and the content of hemocyanin decreased significantly. According to the results of our study, the synergism mechanism may hinder oxygen transport of P. canaliculata, influencing the supply of energy; the ability of immune defense and excretion and metabolic detoxification decreased, prolonging the action time of NI in the body.

Selectively Targeting Breast Cancer Stem Cells by 8-Quinolinol and Niclosamide

Cancer maintenance, metastatic dissemination and drug resistance are sustained by cancer stem cells (CSCs). Triple negative breast cancer (TNBC) is the breast cancer subtype with the highest number of CSCs and the poorest prognosis. Here, we aimed to identify potential drugs targeting CSCs to be further employed in combination with standard chemotherapy in TNBC treatment. The anti-CSC efficacy of up to 17 small drugs was tested in TNBC cell lines using cell viability assays on differentiated cancer cells and CSCs. Then, the effect of 2 selected drugs (8-quinolinol -8Q- and niclosamide -NCS-) in the cancer stemness features were evaluated using mammosphere growth, cell invasion, migration and anchorage-independent growth assays. Changes in the expression of stemness genes after 8Q or NCS treatment were also evaluated. Moreover, the potential synergism of 8Q and NCS with PTX on CSC proliferation and stemness-related signaling pathways was evaluated using TNBC cell lines, CSC-reporter sublines, and CSC-enriched mammospheres. Finally, the efficacy of NCS in combination with PTX was analyzed in vivo using an orthotopic mouse model of MDA-MB-231 cells. Among all tested drug candidates, 8Q and NCS showed remarkable specific anti-CSC activity in terms of CSC viability, migration, invasion and anchorage independent growth reduction in vitro. Moreover, specific 8Q/PTX and NCS/PTX ratios at which both drugs displayed a synergistic effect in different TNBC cell lines were identified. The sole use of PTX increased the relative presence of CSCs in TNBC cells, whereas the combination of 8Q and NCS counteracted this pro-CSC activity of PTX while significantly reducing cell viability. In vivo, the combination of NCS with PTX reduced tumor growth and limited the dissemination of the disease by reducing circulating tumor cells and the incidence of lung metastasis. The combination of 8Q and NCS with PTX at established ratios inhibits both the proliferation of differentiated cancer cells and the viability of CSCs, paving the way for more efficacious TNBC treatments.

Niclosamide Exposure at Environmentally Relevant Concentrations Efficaciously Inhibited the Growth and Disturbed the Liver-Gut Axis of Adult Male Zebrafish

In the current study, adult male zebrafish fed a normal diet (ND) or high-fat diet (HFD) were exposed to niclosamide (NIC) at environmentally relevant concentrations to reveal the accumulation and distribution in different tissues and evaluate the effects on liver-gut axis. Chemical analysis indicated that the liver bore a greater burden of NIC compared with the brain and gonads in adult zebrafish, and the HFD-fed fish bore greater burden in their liver and brain than those ND-fed fish. The indications from body weight, growth rate, body mass index, micro-CT images, biochemical and pathological changes confirmed that NIC can efficaciously curb weight gain and improve overloads of in plasma insulin and glucose in HFD-fed zebrafish. However, the potential effects on liver-gut axis in ND-fed zebrafish were also elucidated: NIC disturbed mitochondrial energy production, inhibited the glycemic and triacylglycerol biosynthesis but promoted triacylglycerol and free fatty acid catabolism, therefore reduced lipid accumulation in hepatocytes; NIC also impaired the physical barrier, evoked inflammatory and oxidative stress and led to microbiota dysbiosis in the intestine. There findings highlighted the necessity for evaluating its potential impacts on the health of wild animals as well as human beings upon long-term exposure.

Niclosamide-loaded nanoparticles disrupt Candida biofilms and protect mice from mucosal candidiasis

Candida albicans biofilms are a complex multilayer community of cells that are resistant to almost all classes of antifungal drugs. The bottommost layers of biofilms experience nutrient limitation where C. albicans cells are required to respire. We previously reported that a protein Ndu1 is essential for Candida mitochondrial respiration; loss of NDU1 causes inability of C. albicans to grow on alternative carbon sources and triggers early biofilm detachment. Here, we screened a repurposed library of FDA-approved small molecule inhibitors to identify those that prevent NDU1-associated functions. We identified an antihelminthic drug, Niclosamide (NCL), which not only prevented growth on acetate, C. albicans hyphenation and early biofilm growth, but also completely disengaged fully grown biofilms of drug-resistant C. albicans and Candida auris from their growth surface. To overcome the suboptimal solubility and permeability of NCL that is well known to affect its in vivo efficacy, we developed NCL-encapsulated Eudragit EPO (an FDA-approved polymer) nanoparticles (NCL-EPO-NPs) with high niclosamide loading, which also provided long-term stability. The developed NCL-EPO-NPs completely penetrated mature biofilms and attained anti-biofilm activity at low microgram concentrations. NCL-EPO-NPs induced ROS activity in C. albicans and drastically reduced oxygen consumption rate in the fungus, similar to that seen in an NDU1 mutant. NCL-EPO-NPs also significantly abrogated mucocutaneous candidiasis by fluconazole-resistant strains of C. albicans, in mice models of oropharyngeal and vulvovaginal candidiasis. To our knowledge, this is the first study that targets biofilm detachment as a target to get rid of drug-resistant Candida biofilms and uses NPs of an FDA-approved nontoxic drug to improve biofilm penetrability and microbial killing.

A Novel Gelatin-Based Sustained-Release Molluscicide for Control of the Invasive Agricultural Pest and Disease Vector Pomacea canaliculata

Pomacea canaliculata, one of the 100 most destructive invasive species in the world, and it is an important intermediate host of Angiostrongylus cantonensis. The molluscicides in current use are an effective method for controlling snails. However, most molluscicides have no slow-release effect and are toxic to nontarget organisms. Thus, these molluscicides cannot be used on a large scale to effectively act on snails. In this study, gelatin, a safe and nontoxic substance, was combined with sustained-release molluscicide and was found to reduce the toxicity of niclosamide to nontarget organisms. We assessed the effects of gelatin and molluscicide in controlling P. canaliculata snails and eggs. The results demonstrated that the niclosamide retention time with 1.0% and 1.5% gelatin sustained-release agents reached 20 days. Additionally, the mortality rate of P. canaliculata and their eggs increased as the concentration of the niclosamide sustained-release agents increased. The adult mortality rate of P. canaliculata reached 50% after the snails were exposed to gelatin with 0.1 mg/L niclosamide for 48 h. The hatching rate of P. canaliculata was only 28.5% of the normal group after the treatment was applied. The sustained-release molluscicide at this concentration was less toxic to zebrafish, which means that this molluscicide can increase the safety of niclosamide to control P. canaliculata in aquatic environments. In this study, we explored the safety of using niclosamide sustained-release agents with gelatin against P. canaliculata. The results suggest that gelatin is an ideal sustained-release agent that can provide a foundation for subsequent improvements in control of P. canaliculata.

Niclosamide Is a Much More Potent Toxicant of Mitochondrial Respiration than TFM in the Invasive Sea Lamprey (Petromyzon marinus)

Invasive sea lampreys in the Laurentian Great Lakes are controlled by applying TFM (3-trifluoromethyl-4-nitrophenol) and niclosamide to streams infested with their larvae. Both agents uncouple oxidative phosphorylation in the mitochondria, but TFM specifically targets lampreys, which have a lower capacity to detoxify the lampricide. Niclosamide lacks specificity and is more potent than TFM. However, its greater potency is poorly understood. We tested the hypothesis that niclosamide is a stronger uncoupler of mitochondrial oxidative phosphorylation than TFM by measuring oxygen consumption rates in isolated liver mitochondria exposed to physiologically relevant concentrations of TFM, niclosamide, or their mixture (100 TFM:1 niclosamide) at environmentally relevant temperatures (7, 13, and 25 °C). Niclosamide increased State 4 respiration and decreased the respiratory control ratio (RCR) at much lower concentrations than TFM. Calculations of the relative EC₅₀ values, the amount of TFM or niclosamide required to decrease the RCR by 50%, indicated that niclosamide was 40-60 times more potent than TFM. Warmer temperature did not appear to decrease the sensitivity of mitochondria to niclosamide or TFM, as observed in the intact sea lamprey exposed to TFM in warmer waters. We conclude that the extreme sensitivity of mitochondria to niclosamide contributes to its greater in vivo toxicity in the whole animal.

[Molluscicidal effect of 25% wettable powder of pyriclobenzuron sulphate in hilly schistosomiasis-endemic regions]

OBJECTIVE

To evaluate the molluscicidal effect of 25% wettable powder of pyriclobenzuron sulphate (WPPS) against Oncomelania snails in hilly schistosomiasis-endemic regions and test its toxicity to fish.

METHODS

In October 2020, a snail-infested setting which had been cleared was selected in Nanjian County, Yunnan Province and divided into several blocks, and the natural snail mortality was estimated. 25% WPPS was prepared into solutions at concentrations of 1 and 2 g/L, and 25% wettable powder of niclosamide ethanolamine salt (WPNES) was prepared into solutions at a concentration of 2 g/L. The different concentrations of drugs were sprayed evenly, and the same amount of water was used as blank control. Snails were surveyed using the systematic sampling method 1, 3 and 7 days post-treatment, and snail survival was observed. A fish pond was selected in Nanjian County, and 2 kg 25% WPPS was evenly sprayed on the water surface to allow the effective concentration of 20 g/L. Fish mortality was estimated 8, 24, 48 and 72 h post-treatment.

RESULTS

One-day treatment with 1 and 2 g/L WPPS and 2 g/L WPNES resulted in 97.99%, 97.99% and 94.11% adjusted snail mortality rates (χ² = 3.509 and 3.509, both P values > 0.05), and the adjusted snail mortality was all 100% 3 d post-treatment with 1 and 2 g/L WPPS and 2 g/L WPNES, while 7-day treatment with 1 and 2 g/L WPPS and 2 g/L WPNES resulted in 91.75%, 86.57% and 57.76% adjusted snail mortality rates (χ² = 14.893 and 42.284, both P values < 0.05). Treatment with 2 g/L WPPS for 72 h resulted in a 0.67% cumulative mortality rate of fish.

CONCLUSIONS

25% WPPS is effective for snail control and highly safe for fish, which is feasible for use in hilly schistosomiasis-endemic regions.

The anthelmintic drug niclosamide induces GSK-β-mediated β-catenin degradation to potentiate gemcitabine activity, reduce immune evasion ability and suppress pancreatic cancer progression

Niclosamide, a cell-permeable salicylanilide, was approved by the Food and Drug Administration for its anthelmintic efficiency. A growing body of evidence in recent years suggests that niclosamide exhibits potential tumor-suppressive activity. However, the role and molecular mechanism of niclosamide in pancreatic cancer remain unclear. In this study, niclosamide inhibited proliferation of pancreatic cancer cells (PCCs), induced apoptosis via the mitochondrial-mediated pathway, and suppressed cell migration and invasion by antagonizing epithelial-to-mesenchymal transition. Also, niclosamide inhibited tumor growth and metastasis in pancreatic cancer xenograft mouse models. Mechanistically, niclosamide exerted these therapeutic effects via targeting β-catenin. Niclosamide did not reduce β-catenin mRNA expression in PCCs, but significantly downregulated its protein level. Moreover, niclosamide induced β-catenin phosphorylation and protein degradation. Interestingly, niclosamide also induced GSK-3β phosphorylation, which is involved in the ubiquitination degradation of β-catenin. Pharmacological activation of β-catenin by methyl vanillate and β-catenin overexpression abolished the inhibitory effects of niclosamide. Furthermore, niclosamide potentiated the antitumor effect of the chemotherapy drug gemcitabine and reduced the ability of cancer immune evasion by downregulating the expression levels of PD-L1, which is involved in T cell immunity. Thus, our study indicated that niclosamide induces GSK-β-mediated β-catenin degradation to potentiate gemcitabine activity, reduce immune evasion ability, and suppress pancreatic cancer progression. Niclosamide may be a potential therapeutic candidate for pancreatic cancer.

Niclosamide Ethanolamine Salt Alleviates Idiopathic Pulmonary Fibrosis by Modulating the PI3K-mTORC1 Pathway

Idiopathic pulmonary fibrosis (IPF) is an interstitial pneumonia characterized by chronic progressive fibrosis, ultimately leading to respiratory failure and early mortality. Although not fully explored, the major causative factors in IPF pathogenesis are dysregulated fibroblast proliferation and excessive accumulation of extracellular matrix (ECM) deposited by myofibroblasts differentiated from pulmonary fibroblasts. More signalling pathways, including the PI3K-Akt-mTOR and autophagy pathways, are involved in IPF pathogenesis. Niclosamide ethanolamine salt (NEN) is a highly effective multitarget small-molecule inhibitor reported in antitumor studies. Here, we reported that in an IPF animal model treated with NEN for 14 days, attractive relief of pulmonary function and hydroxyproline content were observed. To further explore, the therapeutic effect of NEN in IPF and pathological changes in bleomycin-challenged mouse lung sections were assessed. Additionally, the effects of NEN on abnormal proliferation and ECM production in IPF cell models established with TGF-β1-stimulated A549 cells or DHLF-IPF cells were studied. In nonclinical studies, NEN ameliorated lung function and histopathological changes in bleomycin-challenged mice, and the lung hydroxyproline content was significantly diminished with NEN treatment. In vitro, NEN inhibited PI3K-mTORC1 signalling and arrested the cell cycle to prevent uncontrolled fibroblast proliferation. Additionally, NEN inhibited TGF-β1-induced epithelial–mesenchymal transition (EMT) and ECM accumulation via the mTORC1-4EBP1 axis. Furthermore, NEN-activated noncanonical autophagy resensitized fibroblasts to apoptosis. The above findings demonstrated the potential antifibrotic effect of NEN mediated via modulation of the PI3K-mTORC1 and autophagy pathways. These data provide strong evidence for a therapeutic role for NEN in IPF.

[Molluscicidal effect of immersion with 50% wettable powder of niclosamide ethanolamine salt against Oncomelania hupensis on the soil surface and inside the soil layer in winter]

OBJECTIVE

To evaluate the molluscicidal effect of 50% wettable powder of niclosamide ethanolamine salt (WPNES) against Oncomelania hupensis on the soil surface and inside the soil layer by immersion method in winter.

METHODS

O. hupensis snails were placed on the soil surface and 2, 5 cm and 10 cm under the soil layer outdoors in winter, and then immersed in 50% WPNES at concentrations of 1 mg/L and 2 mg/L for 1, 3 d and 7 d, while dechlorinated water served as controls. Snail mortality was observed following immersion with 50% WPNES on the soil surface and inside the soil layer.

RESULTS

Following immersion with 50% WPNES at concentrations of 2 mg/L and 1 mg/L outdoors in winter, the 3-day corrected snail mortality rates were 98.0% and 76.0% on the soil surface, and the 7-day corrected snail mortality rate was both 100.0%. Following immersion with 50% WPNES at concentrations of 2 mg/L and 1 mg/L outdoors in winter, the 7-day corrected snail mortality rates were 95.5% and 85.6% 2 cm below the soil layer, 66.0% and 6.4% 5 cm below the soil layer. However, the 7-day snail mortality rate swere comparable between the 50% WPNES treatment group (at 2 mg/L and 1 mg/L) and controls 10 cm below the soil layer (both P > 0.05).

CONCLUSIONS

Immersion of 50% WPNES at a concentration of 2 mg/L for 7 days presents a high molluscicidal efficacy against O. hupensis on the soil surface and 5 cm within the soil layers in winter.

Nitro-Deficient Niclosamide Confers Reduced Genotoxicity and Retains Mitochondrial Uncoupling Activity for Cancer Therapy

Niclosamide is an oral anthelmintic drug, approved for use against tapeworm infections. Recent studies suggest however that niclosamide may have broader clinical applications in cancers, spurring increased interest in the functions and mechanisms of niclosamide. Previously, we reported that niclosamide targets a metabolic vulnerability in p53-deficient tumours, providing a basis for patient stratification and personalised treatment strategies. In the present study, we functionally characterised the contribution of the aniline 4'-NO2 group on niclosamide to its cellular activities. We demonstrated that niclosamide induces genome-wide DNA damage that is mechanistically uncoupled from its antitumour effects mediated through mitochondrial uncoupling. Elimination of the nitro group in ND-Nic analogue significantly reduced γH2AX signals and DNA breaks while preserving its antitumour mechanism mediated through a calcium signalling pathway and arachidonic acid metabolism. Lipidomics profiling further revealed that ND-Nic-treated cells retained a metabolite profile characteristic of niclosamide-treated cells. Notably, quantitative scoring of drug sensitivity suggests that elimination of its nitro group enhanced the target selectivity of niclosamide against p53 deficiency. Importantly, the results also raise concern that niclosamide may impose a pleiotropic genotoxic effect, which limits its clinical efficacy and warrants further investigation into alternative drug analogues that may ameliorate any potential unwanted side effects.

The ameliorative effect of niclosamide on bile duct ligation induced liver fibrosis via suppression of NOTCH and Wnt pathways

Liver fibrosis is the conjoint consequence of almost all chronic liver diseases. Cholestatic liver injury is a significant stimulus for fibrotic liver. This study was conducted to investigate the hepatoprotective effect of niclosamide as a NOTCH inhibitor and on the Wnt pathway against cholestatic liver fibrosis (CLF) which was experimentally induced by bile duct ligation (BDL). Rats were randomly divided into five main groups (6 per group): sham, BDL, BDL/niclosamide 5, BDL/niclosamide 10 and niclosamide 10 only group. Niclosamide was administered intraperitoneally (i.p.) for 4 weeks starting at the same day of surgery at doses 5 and 10 mg/kg. Liver function, cholestasis, oxidative stress, inflammation, liver fibrosis, NOTCH signaling pathway and Wnt pathway markers were assessed. Niclosamide (5 and 10 mg/kg) significantly reduced liver enzymes levels, oxidative stress, inflammation and phosphorylated signal transducer and activator of transcription3 (p-STAT3). Niclosamide (5 and 10 mg/kg) also significantly reduced NOTCH pathway (Jagged1, NOTCH2, NOTCH3, HES1, SOX9), Wnt pathway (Wnt5B, and Wnt10A), and fibrosis (transforming growth factor-beta1 (TGF-β1), alpha smooth muscle actin (α-SMA) and collagen deposition with more prominent effect of the higher dose 10 mg/kg. So, this study presents nicloamide as a promising antifibrotic agent in CLF through inhibition of NOTCH and Wnt pathways.

Strategies to target SARS-CoV-2 entry and infection using dual mechanisms of inhibition by acidification inhibitors

Many viruses utilize the host endo-lysosomal network for infection. Tracing the endocytic itinerary of SARS-CoV-2 can provide insights into viral trafficking and aid in designing new therapeutic strategies. Here, we demonstrate that the receptor binding domain (RBD) of SARS-CoV-2 spike protein is internalized via the pH-dependent CLIC/GEEC (CG) endocytic pathway in human gastric-adenocarcinoma (AGS) cells expressing undetectable levels of ACE2. Ectopic expression of ACE2 (AGS-ACE2) results in RBD traffic via both CG and clathrin-mediated endocytosis. Endosomal acidification inhibitors like BafilomycinA1 and NH4Cl, which inhibit the CG pathway, reduce the uptake of RBD and impede Spike-pseudoviral infection in both AGS and AGS-ACE2 cells. The inhibition by BafilomycinA1 was found to be distinct from Chloroquine which neither affects RBD uptake nor alters endosomal pH, yet attenuates Spike-pseudovirus entry. By screening a subset of FDA-approved inhibitors for functionality similar to BafilomycinA1, we identified Niclosamide as a SARS-CoV-2 entry inhibitor. Further validation using a clinical isolate of SARS-CoV-2 in AGS-ACE2 and Vero cells confirmed its antiviral effect. We propose that Niclosamide, and other drugs which neutralize endosomal pH as well as inhibit the endocytic uptake, could provide broader applicability in subverting infection of viruses entering host cells via a pH-dependent endocytic pathway.

Improved Endothelium-Dependent Relaxation of Thoracic Aorta in Niclosamide-Treated Diabetic Rats

Diabetes-induced endothelial dysfunction is critical for the development of diabetic cardiovascular complications. The aim of this study was to investigate the effect of niclosamide (Nic) on vascular endothelial dysfunction in streptozotocin (STZ)-induced diabetic rats. Male Sprague-Dawley rats were injected with a single intraperitoneal injection of STZ (75 mg/kg) to induce type 1 diabetes, and Nic (10 mg/kg) was intraperitoneally administered per day for 4 weeks. Endothelial function was evaluated as carbachol (CCh, an endothelium-dependent vasodilator)-evoked relaxation in the experiments performed on isolated thoracic aortas. The changes in the protein expressions of phosphorylated eNOS at serine 1177 (p-eNOSSer1177) and phosphorylated VASP at serine 239 (p-VASPSer239) of the rat aortas were analyzed by western blotting to determine whether NO/cGMP signaling is involved in the mechanism of Nic. STZ-injected rats had higher fasting blood glucose and less body weight compared to control rats (p < 0.05). Nic treatment did not affect blood glucose levels or body weights of the rats. CCh-induced endothelium-dependent relaxation of the aortic rings was significantly decreased in diabetic rats compared to control (Emax = 66.79 ± 7.41% and 90.28 ± 5.55%, respectively; p < 0.05). CCh-induced relaxation response was greater in Nic-treated diabetic rats compared to diabetic rats (Emax = 91.56 ± 1.20% and 66.79 ± 7.41%, respectively; p < 0.05). Phosphorylation of eNOS and VASP in aortic tissues was significantly reduced in diabetic rats, which were markedly increased by Nic treatment (p < 0.05). We demonstrated that Nic improved endothelial dysfunction possibly through the activation of NO/cGMP signaling without affecting hyperglycemia in diabetic rats. Our results suggesting that Nic has potential of repurposing for diabetic cardiovascular complications.

Quinacrine and Niclosamide Promote Neurite Growth in Midbrain Dopaminergic Neurons Through the Canonical BMP-Smad Pathway and Protect Against Neurotoxin and α-Synuclein-Induced Neurodegeneration

Parkinson's disease is a neurodegenerative disorder characterised by nigrostriatal dopaminergic degeneration, and intracellular α-synuclein aggregation. Current pharmacological treatments are solely symptomatic so there is a need to identify agents that can slow or stop dopaminergic degeneration. One proposed class of therapeutics are neurotrophic factors which promote the survival of nigrostriatal dopaminergic neurons. However, neurotrophic factors need to be delivered directly to the brain. An alternative approach may be to identify pharmacological agents which can reach the brain to stimulate neurotrophic factor expression and/or their signalling pathways in dopaminergic neurons. BMP2 is a neurotrophic factor that is expressed in the human substantia nigra; exogenous BMP2 administration protects against dopaminergic degeneration in in vitro models of PD. In this study, we investigated the neurotrophic potential of two FDA-approved drugs, quinacrine and niclosamide, that are modulators of BMP2 signalling. We report that quinacrine and niclosamide, like BMP2, significantly increased neurite length, as a readout of neurotrophic action, in SH-SY5Y cells and dopaminergic neurons in primary cultures of rat ventral mesencephalon. We also show that these effects of quinacrine and niclosamide require the activation of BMP-Smad signalling. Finally, we demonstrate that quinacrine and niclosamide are neuroprotective against degeneration induced by the neurotoxins, MPP+ and 6-OHDA, and by viral-mediated overexpression of α-synuclein in vitro. Collectively, this study identifies two drugs, that are safe for use in patients' to 'are approved for human use, that exert neurotrophic effects on dopaminergic neurons through modulation of BMP-Smad signalling. This rationalises the further study of drugs that target the BMP-Smad pathway as potential neuroprotective pharmacotherapy for Parkinson's disease.

SARS-CoV-2-mediated dysregulation of metabolism and autophagy uncovers host-targeting antivirals

Viruses manipulate cellular metabolism and macromolecule recycling processes like autophagy. Dysregulated metabolism might lead to excessive inflammatory and autoimmune responses as observed in severe and long COVID-19 patients. Here we show that SARS-CoV-2 modulates cellular metabolism and reduces autophagy. Accordingly, compound-driven induction of autophagy limits SARS-CoV-2 propagation. In detail, SARS-CoV-2-infected cells show accumulation of key metabolites, activation of autophagy inhibitors (AKT1, SKP2) and reduction of proteins responsible for autophagy initiation (AMPK, TSC2, ULK1), membrane nucleation, and phagophore formation (BECN1, VPS34, ATG14), as well as autophagosome-lysosome fusion (BECN1, ATG14 oligomers). Consequently, phagophore-incorporated autophagy markers LC3B-II and P62 accumulate, which we confirm in a hamster model and lung samples of COVID-19 patients. Single-nucleus and single-cell sequencing of patient-derived lung and mucosal samples show differential transcriptional regulation of autophagy and immune genes depending on cell type, disease duration, and SARS-CoV-2 replication levels. Targeting of autophagic pathways by exogenous administration of the polyamines spermidine and spermine, the selective AKT1 inhibitor MK-2206, and the BECN1-stabilizing anthelmintic drug niclosamide inhibit SARS-CoV-2 propagation in vitro with IC50 values of 136.7, 7.67, 0.11, and 0.13 μM, respectively. Autophagy-inducing compounds reduce SARS-CoV-2 propagation in primary human lung cells and intestinal organoids emphasizing their potential as treatment options against COVID-19.

[Effectiveness and cost analysis of two chemical molluscicides in hilly schistosomiasis-endemic regions]

OBJECTIVE

To investigate the effectiveness and cost of 50% and 80% wettable powder of niclosamide ethanolamine salt (NESWP) and 26% metaldehyde and niclosamide suspension concentrate (MNSC) in hilly schistosomiasis-endemic regions, so as to provide insights into the selection of chemical molluscicides in hilly regions.

METHODS

In September 2020, a wasteland in Guanshanqiao Village, Yanrui Township, Yushan County of Jiangxi Province was selected as the experimental region, which was sectioned into five blocks and defined as four experimental groups (A₁, A₂, B, C) and a blank control group (D). 80% NESWP were given at doses of 1 g/m² and 1.5 g/m² in groups A₁ and A₂ using the spraying method, 50% NESWP was given at a dose of 2 g/m² in Group B using the spraying method, and 26% MNSC was at a dose of 4 g/m² in Group C using the spraying method, while no chemical treatment was given in Group D. Snail survey was performed using a systematic sampling method before chemical treatment and 1, 3, 7 d and 15 d post-treatment to examine the molluscicidal effect, and all molluscicidal costs were estimated to calculate the cost of chemical treatment per 1 m² and the cost of the reduction in the mean density of living snails per 1%.

RESULTS

The highest mortality of snails was 78.95% and the lowest density of living snails was 0.2388 snails/0.1 m² in the experimental groups within 7 d of chemical treatment, and the highest mortality of snails was 94.74% and the lowest density of living snails was 0.058 0 snails/0.1 m² 7 d post-treatment. There were no significant differences in the snail mortality among the A₁, A₂, B and C groups 1 (χ² = 2.250, P > 0.05), 3 (χ² = 1.779, P > 0.05) or 15 d post-treatment (χ² = 2.286, P > 0.05), while a significant difference was detected in the snail mortality among the four groups 7 d post-treatment (χ² = 7.990, P = 0.046). In addition, there were no significant differences in the snail mortality between A₁ and A₂ groups 1 (χ² = 0.724, P > 0.05), 3 (χ² = 0.584, P > 0.05), 7 (χ² = 0.400, P > 0.05) or 15 d post-treatment (χ² = 0.251, P > 0.05). The costs of chemical treatment per 1 m² were 0.58, 0.60, 0.64 Yuan and 0.73 Yuan in groups A₁, A₂, B and C, and the costs of the mean density of living snail per 1% reduction were 19.29, 20.44, 21.68 Yuan and 23.53 Yuan in groups A₁, A₂, B and C, respectively.

CONCLUSIONS

80% NESWP shows a high molluscicidal efficacy and low cost in hilly schistosomiasis-endemic regions.

AR-V7 in Metastatic Prostate Cancer: A Strategy beyond Redemption

Metastatic prostate cancer is the most common cancer in males and the fifth cause of cancer mortality worldwide. Despite the major progress in this field, leading to the approval of novel anti-androgens, the prognosis is still poor. A significant number of patients acquire an androgen receptor splice variant 7 (AR-V7), which is constitutively activated and lacks the ligand-binding domain (LBD) while maintaining the nuclear localization signal and DNA-binding domain (DBD). This conformational change, even in the absence of the ligand, allows its retention within the nucleus, where it acts as a transcription factor repressing crucial tumor suppressor genes. AR-V7 is an important oncogenic driver and plays a role as an early diagnostic and prognostic marker, as well as a therapeutic target for antagonists such as niclosamide and TAS3681. Anti-AR-V7 drugs have shown promise in recent clinical investigations on this subset of patients. This mini-review focuses on the relevance of AR-V7 in the clinical manifestations of castration-resistant prostate cancer (CRPC) and summarizes redemptive therapeutic strategies.

Efficacy of niclosamide on the intra-abdominal inflammatory environment in endometriosis

Endometriosis, a common gynecological disease, causes chronic pelvic pain and infertility in women of reproductive age. Due to the limited efficacy of current therapies, a critical need exists to develop new treatments for endometriosis. Inflammatory dysfunction, instigated by abnormal macrophage (MΦ) function, contributes to disease development and progression. However, the fundamental role of the heterogeneous population of peritoneal MΦ and their potential druggable functions is uncertain. Here we report that GATA6-expressing large peritoneal MΦ (LPM) were increased in the peritoneal cavity following lesion induction. This was associated with increased cytokine and chemokine secretion in the peritoneal fluid (PF), as well as MΦ infiltration, vascularization and innervation in endometriosis-like lesions (ELL). Niclosamide, an FDA-approved anti-helminthic drug, was effective in reducing LPM number, but not small peritoneal MΦ (SPM), in the PF. Niclosamide also inhibits aberrant inflammation in the PF, ELL, pelvic organs (uterus and vagina) and dorsal root ganglion (DRG), as well as MΦ infiltration, vascularization and innervation in the ELL. PF from ELL mice stimulated DRG outgrowth in vitro, whereas the PF from niclosamide-treated ELL mice lacked the strong stimulatory nerve growth response. These results suggest LPM induce aberrant inflammation in endometriosis promoting lesion progression and establishment of the inflammatory environment that sensitizes peripheral nociceptors in the lesions and other pelvic organs, leading to increased hyperalgesia. Our findings provide the rationale for targeting LPM and their functions with niclosamide and its efficacy in endometriosis as a new non-hormonal therapy to reduce aberrant inflammation which may ultimately diminish associated pain.