Repurposing Niclosamide to Modulate Renal RNA-Binding Protein HuR for the Treatment of Diabetic Nephropathy in db/db Mice.

Hu antigen R (HuR) plays a key role in regulating genes critical to the pathogenesis of diabetic nephropathy (DN). This study investigates the therapeutic potential of niclosamide (NCS) as an HuR inhibitor in DN. Uninephrectomized mice were assigned to four groups: normal control; untreated db/db mice terminated at 14 and 22 weeks, respectively; and db/db mice treated with NCS (20 mg/kg daily via i.p.) from weeks 18 to 22. Increased HuR expression was observed in diabetic kidneys from db/db mice, which was mitigated by NCS treatment. Untreated db/db mice exhibited obesity, progressive hyperglycemia, albuminuria, kidney hypertrophy and glomerular mesangial matrix expansion, increased renal production of fibronectin and a-smooth muscle actin, and decreased glomerular WT-1+-podocytes and nephrin expression. NCS treatment did not affect mouse body weight, but reduced blood glucose and HbA1c levels and halted the DN progression observed in untreated db/db mice. Renal production of inflammatory and oxidative stress markers (NF-κBp65, TNF-a, MCP-1) and urine MDA levels increased during disease progression in db/db mice but were halted by NCS treatment. Additionally, the Wnt1-signaling-pathway downstream factor, Wisp1, was identified as a key downstream mediator of HuR-dependent action and found to be markedly increased in db/db mouse kidneys, which was normalized by NCS treatment. These findings suggest that inhibition of HuR with NCS is therapeutic for DN by improving hyperglycemia, renal inflammation, and oxidative stress. The reduction in renal Wisp1 expression also contributes to its renoprotective effects. This study supports the potential of repurposing HuR inhibitors as a novel therapy for DN.

Albumin-Based Microneedles for Spatiotemporal Delivery of Temozolomide and Niclosamide to Resistant Glioblastoma.

Glioblastoma (GBM) is the most common and aggressive malignant brain tumor. Standard therapy includes maximal surgical resection, radiotherapy, and adjuvant temozolomide (TMZ) administration. However, the rapid development of TMZ resistance and the impermeability of the blood-brain barrier (BBB) significantly hinder the therapeutic efficacy. Herein, we developed spatiotemporally controlled microneedle patches (BMNs) loaded with TMZ and niclosamide (NIC) to overcome GBM resistance. We found that hyaluronic acid (HA) increased the viscosity of bovine serum albumin (BSA) and evidenced that concentrations of BSA/HA exert an impact degradation rates exposure to high-temperature treatment, showing that the higher BSA/HA concentrations result in slower drug release. To optimize drug release rates and ensure synergistic antitumor effects, a 15% BSA/HA solution constituting the bottoms of BMNs was chosen to load TMZ, showing sustained drug release for over 28 days, guaranteeing long-term DNA damage in TMZ-resistant cells (U251-TR). Needle tips made from 10% BSA/HA solution loaded with NIC released the drug within 14 days, enhancing TMZ's efficacy by inhibiting the activity of O6-methylguanine-DNA methyltransferase (MGMT). BMNs exhibit superior mechanical properties, bypass the BBB, and gradually release the drug into the tumor periphery, thus significantly inhibiting tumor proliferation and expanding median survival in mice. The on-demand delivery of BMNs patches shows a strong translational potential for clinical applications, particularly in synergistic GBM treatment.

Anthelmintic activity and pathophysiological effect of anthelmintic drugs against carcinogenic liver fluke, Opisthorchis viverrini.

Human liver fluke, Opisthorchis viverrini poses a significant risk for development of cholangiocarcinoma (CCA) in Thailand, primarily attributed to consumption of undercooked cyprinoid fishes. The current use of anthelmintic drug treatment such as praziquantel (PZQ), as the main therapeutic agent against O. viverrini. There is a need to explore the efficacy of alternative anthelmintic drugs for O. viverrini treatment. This study aimed to assess the efficacy of anthelmintic drugs, which are commonly use in endemic areas of Southeast Asian countries; PZQ, albendazole (AL), niclosamide (NI), and mebendazole (ME) at concentrations of 600, 400, 500, and 500 mg/ml. The study included a negative and positive control group treated with roswell park memorial institute (RPMI) and PZQ. Reactive oxygen species (ROS) levels, indicative of oxidative stress, were quantified using 2',7'-dichlorofluorescein diacetate staining. Morphological changes were observed using scanning electron microscopy. Furthermore, motility assessments were conducted at various time points (0, 5, 30 minutes, 1, 3, 6, 12, and 24 hours), calculating relative motility (RM) and survival index (SI). The results revealed a significant increase of ROS levels with the intensity and corrected total worm fluorescence (CTWF) mostly observed in order of PZQ, followed by NI, ME, and AL, respectively. Morphological damage was presented the tegumental swelling, papillae changes, and disruption of microvilli (Mv), particularly in the group treated with the most effective anthelmintics PZQ, NI, ME, and AL, while negative control group did not exhibit such alterations. Also, the most efficacy for suppressing the motility of adult worms were displayed in PZQ treatment group, followed by NI, ME, and AL, respectively. Overall, first novel findings suggest that apart from NI, ME, and AL demonstrate potential as alternative therapeutic options for O. viverrini infection. Furthermore, animal model is needed to investigate the efficacy of NI, ME, and AL compare with standard treatment.

Pharmacological investigation of new niclosamide-based isatin hybrids as antiproliferative, antioxidant, and apoptosis inducers.

A group of Niclosamide-linked isatin hybrids (Xo, X1, and X2) was created and examined using IR, 1HNMR, 13C NMR, and mass spectrometry. These hybrids' cytotoxicity, antioxidant, cell cycle analysis, and apoptosis-inducing capabilities were identified. Using the SRB assay, their cytotoxicity against the human HCT-116, MCF-7, and HEPG-2 cancer cell lines, as well as VERO (African Green Monkey Kidney), was evaluated. Compound X1 was the most effective compound. In HCT-116 cells, compound X1 produced cell cycle arrest in the G1 phase, promoted cell death, and induced apoptosis through mitochondrial membrane potential breakdown in comparison to niclosamide and the control. Niclosamide and compound X1 reduced reactive oxygen species generation and modulated the gene expression of BAX, Bcl-2, Bcl-xL, and PAR-4 in comparison to the control. Docking modeling indicated their probable binding modalities with the XIAP BIR2 domain, which selectively binds caspase-3/7, and highlighted their structural drivers of activity for further optimization investigations. Computational in silico modeling of the new hybrids revealed that they presented acceptable physicochemical values as well as drug-like characteristics, which may introduce them as drug-like candidates. The study proved that compound X1 might be a novel candidate for the development of anticancer agents as it presents antiproliferative activity mediated by apoptosis.

Repurposing of niclosamide, an anthelmintic, by targeting ERK/MAPK signaling pathway in the experimental paradigm of autism spectrum disorders.

AIM: The current study explores niclosamide's neuroprotective potential in an animal model of autism spectrum disorder (ASD) and goes further to understand how the ERK/MAPK signaling pathway is thought to contribute to this activity. METHODS: In order to create an autism-like phenotype in rats, 4 µl of 1 M PPA was infused intracerebroventricularly. The oral treatment with niclosamide (50 and 100 mg/kg) and risperidone (1 mg/kg) (used as standard) was given from 3rd to 30th day. Between the 14th and 28th day, behavioral assessments were made for sociability, stereotypy, anxiety, depression, novelty preference, repetitive behavior, and perseverative behavior. The animals were euthanized on the 29th day, and oxidative stress markers were assessed in the brain homogenate. The levels of neuroinflammatory cytokines such as TNF-α, IL-6, NF-κB, IFN-γ and glutamate were estimated using ELISA kits. To assess the involvement of the ERK/MAPK signaling pathway, levels of Nrf2 and ERK2 were also measured. KEY FINDINGS: Niclosamide therapy significantly restored behavioral, biochemical, neurological, and molecular impairments. Hence, niclosamide could be a potential neurotherapeutic candidate for further studies for use in ASD.

In vitro synergistic antiviral activity of repurposed drugs against enterovirus 71.

Enteroviruses cause viral diseases that are harmful to children. Hand, foot, and mouth disease (HFMD) with neurological complications is mainly caused by enterovirus 71 (EV71). Despite its clinical importance, there is no effective antiviral drug against EV71. However, several repurposed drugs have been shown to have antiviral activity against related viruses. Treatments with single drugs and two-drug combinations were performed in vitro to assess anti-EV71 activity. Three repurposed drug candidates with broad-spectrum antiviral activity were found to demonstrate potent anti-EV71 activity: prochlorperazine, niclosamide, and itraconazole. To improve antiviral activity, combinations of two drugs were tested. Niclosamide and itraconazole showed synergistic antiviral activity in Vero cells, whereas combinations of niclosamide-prochlorperazine and itraconazole-prochlorperazine showed only additive effects. Furthermore, the combination of itraconazole and prochlorperazine showed an additive effect in neuroblastoma cells. Itraconazole and prochlorperazine exert their antiviral activities by inhibiting Akt phosphorylation. Repurposing of drugs can provide a treatment solution for HFMD, and our data suggest that combining these drugs can enhance that efficacy.

Biomineralization-Tuned Nanounits Reprogram the Signal Transducer and Activator of Transcription 3 Signaling for Ferroptosis-Immunotherapy in Cancer Stem Cells.

Cancer stem cells (CSCs) are promising targets for improving anticancer treatment outcomes while eliminating recurrence, but their treatment remains a major challenge. Here, we report a nanointegrative strategy to realize CSC-targeted ferroptosis-immunotherapy through spatiotemporally controlled reprogramming of STAT3-regulated signaling circuits. Specifically, STAT3 inhibitor niclosamide (Ni) and an experimental ferroptosis drug (1S, 3R)-RSL3 (RSL3) are integrated into hyaluronic acid-modified amorphous calcium phosphate (ACP) nanounits through biomineralization (CaP-PEG-HA@Ni/RSL3), which could be recognized by CD44-overexpressing CSCs and released in a synchronized manner. Ni inhibits the CSC-intrinsic STAT3-PD-L1 axis to stimulate adaptive immunity and enhance interferon gamma (IFNγ) secretion by CD8+ T cells to downregulate SLC7A11 and SLC3A2 for blocking glutathione biosynthesis. Meanwhile, Ni-dependent STAT3 inhibition also upregulates ACSL4 through downstream signaling and IFNγ feedback. These effects cooperate with RSL3-mediated GPX4 deactivation to induce pronounced ferroptosis. Furthermore, CaP-PEG-HA@Ni/RSL3 also impairs the immunosuppressive M2-like tumor-associated macrophages, while Ca2+ ions released from degraded ACP could chelate with lipid peroxides in ferroptotic CSCs to avoid CD8+ T-cell inhibition, thus boosting the effector function of activated CD8+ T cells. This study offers a cooperative ferroptosis-immunotherapeutic approach for the treatment of refractory cancer.

Human infections by Hymenolepis diminuta in Europe: a case report and literature review.

We performed a review of published and gray literature of human Hymenolepis diminuta cases across Europe up to July 2022. Of all detectable publications and records, we further analyzed only those that contained demographic, clinical or epidemiological data regarding the infected subjects. Additionally, one case of hymenolepiasis in a 16-mo-old boy living in the urban part of Belgrade was included in the analysis. Published studies were based in 13/50 European countries and identified 104 laboratory-confirmed cases in total. Almost one-half (49%) of all cases originated from Mediterranean countries. Among symptomatic children, the infection most often manifested with diarrhea, abdominal pain, allergic reaction and behavioral changes. The diagnosis was made by the detection and identification of H. diminuta eggs or parts of strobila in stool samples, although cases of misdiagnosis were also reported. The parasite clearance was established with praziquantel or niclosamide, while the administration of albendazole or mebendazole led to unfavorable results. Future multicentric prospective studies focused on infection screening and the gathering of detailed sociodemographic and clinical data could provide an updated insight into the true distribution and characteristics of H. diminuta infection across Europe.

The Antifungal Potential of Niclosamide and Structurally Related Salicylanilides.

Human mycoses cover a diverse field of fungal diseases from skin disorders to systemic invasive infections and pose an increasing global health problem based on ineffective treatment options, the hampered development of new efficient drugs, and the emergence of resistant fungal strains. Niclosamide is currently applied for the treatment of worm infections. Its mechanisms of action, which include the suppression of mitochondrial oxidative phosphorylation (also known as mitochondrial uncoupling), among others, has led to a repurposing of this promising anthelmintic drug for the therapy of further human diseases such as cancer, diabetes, and microbial infections. Given the urgent need to develop new drugs against fungal infections, the considerable antifungal properties of niclosamide are highlighted in this review. Its chemical and pharmacological properties relevant for drug development are also briefly mentioned, and the described mitochondria-targeting mechanisms of action add to the current arsenal of approved antifungal drugs. In addition, the activities of further salicylanilide-based niclosamide analogs against fungal pathogens, including agents applied in veterinary medicine for many years, are described and discussed for their feasibility as new antifungals for humans. Preliminary structure-activity relationships are determined and discussed. Various salicylanilide derivatives with antifungal activities showed increased oral bioavailabilities when compared with niclosamide. The simple synthesis of salicylanilide-based drugs also vouchsafes a broad and cost-effective availability for poorer patient groups. Pertinent literature is covered until 2024.

Impact of Oncogenic Changes in p53 and KRAS on Macropinocytosis and Ferroptosis in Colon Cancer Cells and Anticancer Efficacy of Niclosamide with Differential Effects on These Two Processes.

Mutations in p53 and KRAS are seen in most cases of colon cancer. The impact of these mutations on signaling pathways related to cancer growth has been studied in depth, but relatively less is known on their effects on amino acid transporters in cancer cells. This represents a significant knowledge gap because amino acid nutrition in cancer cells profoundly influences macropinocytosis and ferroptosis, two processes with opposing effects on tumor growth. Here, we used isogenic colon cancer cell lines to investigate the effects of p53 deletion and KRAS activation on two amino acid transporters relevant to macropinocytosis (SLC38A5) and ferroptosis (SLC7A11). Our studies show that the predominant effect of p53 deletion is to induce SLC7A11 with the resultant potentiation of antioxidant machinery and protection of cancer cells from ferroptosis, whereas KRAS activation induces not only SLC7A11 but also SLC38A5, thus offering protection from ferroptosis as well as improving amino acid nutrition in cancer cells via accelerated macropinocytosis. Niclosamide, an FDA-approved anti-helminthic, blocks the functions of SLC7A11 and SLC38A5, thus inducing ferroptosis and suppressing macropinocytosis, with the resultant effective reversal of tumor-promoting actions of oncogenic changes in p53 and KRAS. These findings underscore the potential of this drug in colon cancer treatment.

Structural investigations on the mitochondrial uncouplers niclosamide and FCCP.

There has been renewed interest in using mitochondrial uncoupler compounds such as niclosamide and carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone (FCCP) for the treatment of obesity, hepatosteatosis and diseases where oxidative stress plays a role. However, both FCCP and niclosamide have undesirable effects that are not due to mitochondrial uncoupling, such as inhibition of mitochondrial oxygen consumption by FCCP and induction of DNA damage by niclosamide. Through structure-activity analysis, we identified FCCP analogues that do not inhibit mitochondrial oxygen consumption but still provided good, although less potent, uncoupling activity. We also characterized the functional role of the niclosamide 4'-nitro group, the phenolic hydroxy group and the anilide amino group in mediating uncoupling activity. Our structural investigations provide important information that will aid further drug development.

Niclosamide potentiates TMEM16A and induces vasoconstriction.

The TMEM16A calcium-activated chloride channel is a promising therapeutic target for various diseases. Niclosamide, an anthelmintic medication, has been considered a TMEM16A inhibitor for treating asthma and chronic obstructive pulmonary disease (COPD) but was recently found to possess broad-spectrum off-target effects. Here, we show that, under physiological Ca2+ (200-500 nM) and voltages, niclosamide acutely potentiates TMEM16A. Our computational and functional characterizations pinpoint a putative niclosamide binding site on the extracellular side of TMEM16A. Mutations in this site attenuate the potentiation. Moreover, niclosamide potentiates endogenous TMEM16A in vascular smooth muscle cells, triggers intracellular calcium increase, and constricts the murine mesenteric artery. Our findings advise caution when considering clinical applications of niclosamide as a TMEM16A inhibitor. The identification of the putative niclosamide binding site provides insights into the mechanism of TMEM16A pharmacological modulation and provides insights into developing specific TMEM16A modulators to treat human diseases.

Predicting lung exposure of intramuscular niclosamide as an antiviral agent: Power-law based pharmacokinetic modeling.

Niclosamide, a potent anthelmintic agent, has emerged as a candidate against COVID-19 in recent studies. Its formulation has been investigated extensively to address challenges related to systemic exposure. In this study, niclosamide was formulated as a long-acting intramuscular injection to achieve systemic exposure in the lungs for combating the virus. To establish the dose-exposure relationship, a hamster model was selected, given its utility in previous COVID-19 infection studies. Pharmacokinetic (PK) analysis was performed using NONMEM and PsN. Hamsters were administered doses of 55, 96, 128, and 240 mg/kg with each group comprising five animals. Two types of PK models were developed, linear models incorporating partition coefficients and power-law distributed models, to characterize the relationship between drug concentrations in the plasma and lungs of the hamsters. Numerical and visual diagnostics, including basic goodness-of-fit and visual predictive checks, were employed to assess the models. The power-law-based PK model not only demonstrated superior numerical performance compared with the linear model but also exhibited better agreement in visual diagnostic evaluations. This phenomenon was attributed to the nonlinear relationship between drug concentrations in the plasma and lungs, reflecting kinetic heterogeneity. Dose optimization, based on predicting lung exposure, was conducted iteratively across different drug doses, with the minimum effective dose estimated to be ~1115 mg/kg. The development of a power-law-based PK model proved successful and effectively captured the nonlinearities observed in this study. This method is expected to be applicable for investigating the drug disposition of specific formulations in the lungs.

Molluscicide screening and identification of novel targets against Pomacea canaliculata.

BACKGROUND: Owing to the nonavailability of any clear targets for molluscicides against Pomacea canaliculata, target-based screening strategy cannot be employed. In this study, the molluscicidal effects of typical pesticides on P. canaliculata were evaluated to obtain the molluscicide target. A series of arylpyrrole compounds were synthesized based on the discovered target, and their structure-activity relationships explored. A preliminary strategy for screening molluscicides based on specific targets was also developed. RESULTS: A laboratory colony of P. canaliculata was developed, which showed no difference in sensitivity to niclosamide compared with the wild group, while exhibiting a higher stability against pesticide response. Mitochondrial adenosine triphosphate (ATP) synthase inhibitors and mitochondrial membrane potential uncouplers were identified and validated as potential targets for molluscicide screening against P. canaliculata. A series of arylpyrrole compounds were designed and synthesized. The median lethal concentration of 4-bromo-2-(4-chlorophenyl)-5-(trifluoromethyl)-1H-pyrrole-3-carbonitrile (Compound 102) was 10-fold lower than that of niclosamide. CONCLUSION: New molluscicide targets were discovered and validated, and preliminary strategies were explored for pesticide screening based on these targets. Compound 102 exhibited a high molluscicidal activity and had a great potential value for exploring a molluscicide to control P. canaliculata. © 2024 Society of Chemical Industry.

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.

A randomized trial to assess the acceleration of viral clearance by the combination Favipiravir/Ivermectin/Niclosamide in mild-to-moderate COVID-19 adult patients (FINCOV).

BACKGROUND: The efficacy of the viral clearance and clinical outcomes of favipiravir (FPV) in outpatients being treated for coronavirus disease 2019 (COVID-19) is unclear. Ivermectin (IVM), niclosamide (NCL), and FPV demonstrated synergistic effects in vitro for exceed 78% inhibiting severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) replication. METHODS: A phase 2, open-label, 1:1, randomized, controlled trial was conducted on Thai patients with mild-to-moderate COVID-19 who received either combination FPV/IVM/NCL therapy or FPV alone to assess the rate of viral clearance among individuals with mild-to-moderate COVID-19. RESULTS: Sixty non-high-risk comorbid patients with mild-to-moderate COVID-19 were randomized; 30 received FPV/IVM/NCL, and 30 received FPV alone. Mixed-effects multiple linear regression analysis of the cycle threshold value from SARS-CoV-2 PCR demonstrated no statistically significant differences in viral clearance rates between the combined FPV/IVM/NCL therapy group and the FPV-alone group. World Health Organization Clinical Progression scores and symptomatic improvement did not differ between arms on days 3, 6, and 10, and no adverse events were reported. No patients required hospitalization, intensive care unit admission, or supplemental oxygen or died within 28 days. C-reactive protein on day 3 was lower in the FPV/IVM/NCL group. CONCLUSION: Viral clearance rates did not differ significantly between the FPV/IVM/NCL combination therapy and FPV-alone groups of individuals with mild-to-moderate COVID-19, although the combined regimen demonstrated a synergistic effect in vitro. No discernible clinical benefit was observed. Further research is required to explore the potential benefits of FVP beyond its antiviral effects. TRIAL REGISTRATION: TCTR20230403007, Registered 3 April 2023 - Retrospectively registered,https://trialsearch.who.int/Trial2.aspx?TrialID=TCTR20230403007.

Computational drug repositioning identifies niclosamide and tribromsalan as inhibitors of Mycobacterium tuberculosis and Mycobacterium abscessus.

Tuberculosis (TB) is still a major global health challenge, killing over 1.5 million people each year, and hence, there is a need to identify and develop novel treatments for Mycobacterium tuberculosis (M. tuberculosis). The prevalence of infections caused by nontuberculous mycobacteria (NTM) is also increasing and has overtaken TB cases in the United States and much of the developed world. Mycobacterium abscessus (M. abscessus) is one of the most frequently encountered NTM and is difficult to treat. We describe the use of drug-disease association using a semantic knowledge graph approach combined with machine learning models that has enabled the identification of several molecules for testing anti-mycobacterial activity. We established that niclosamide (M. tuberculosis IC90 2.95 µM; M. abscessus IC90 59.1 µM) and tribromsalan (M. tuberculosis IC90 76.92 µM; M. abscessus IC90 147.4 µM) inhibit M. tuberculosis and M. abscessus in vitro. To investigate the mode of action, we determined the transcriptional response of M. tuberculosis and M. abscessus to both compounds in axenic log phase, demonstrating a broad effect on gene expression that differed from known M. tuberculosis inhibitors. Both compounds elicited transcriptional responses indicative of respiratory pathway stress and the dysregulation of fatty acid metabolism.

Design and fabrication of electrochemical sensor based on NiO/Ni@C-Fe3O4/CeO2 for the determination of niclosamide.

In this study, we aimed to enhance and accelerate the electrochemical properties of a glassy carbon-based voltammetric sensor electrode. This was achieved through the modification of the electrode using a nanocomposite derived from a metal-organic framework, which was embedded onto a substrate consisting of metal oxide nanoparticles. The final product was an electrocatalyst denoted as NiO/Ni@C-Fe3O4/CeO2, tailored for the detection of the drug niclosamide. Several techniques, including FT-IR, XRD, XPS, FE-SEM, TEM, and EDS, were employed to characterize the structure and morphology of this newly formed electroactive catalyst. Subsequently, the efficiency of this electrocatalyst was evaluated using cyclic voltammetry and electrochemical impedance spectroscopy techniques. Differential pulse voltammetry was also utilized to achieve heightened sensitivity and selectivity. A comprehensive exploration of key factors such as the catalyst quantity, optimal instrumental parameters, scan rate influence, and pH effect was undertaken, revealing a well-regulated reaction process. Furthermore, the sensor's analytical performance parameters were determined. This included establishing the linear detection range for the target compound within a specified concentration interval of 2.92 nM to 4.97 µM. The detection limit of 0.91 nM, repeatability of 3.1%, and reproducibility of 4.8% of the sensor were calculated, leading to the observation of favorable stability characteristics. Conclusively, the developed electrochemical sensor was successfully employed for the quantification of niclosamide in urine samples and niclosamide tablets. This application highlighted not only the sensor's high selectivity but also the satisfactory and accurate outcomes obtained from these measurements.

Lipid-Based Self-Microemulsion of Niclosamide Achieved Enhanced Oral Delivery and Anti-Tumor Efficacy in Orthotopic Patient-Derived Xenograft of Hepatocellular Carcinoma in Mice.

Introduction: We previously identified niclosamide as a promising repurposed drug candidate for hepatocellular carcinoma (HCC) treatment. However, it is poorly water soluble, limiting its tissue bioavailability and clinical application. To overcome these challenges, we developed an orally bioavailable self-microemulsifying drug delivery system encapsulating niclosamide (Nic-SMEDDS). Methods: Nic-SMEDDS was synthesized and characterized for its physicochemical properties, in vivo pharmacokinetics and absorption mechanisms, and in vivo therapeutic efficacy in an orthotopic patient-derived xenograft (PDX)-HCC mouse model. Niclosamide ethanolamine salt (NEN), with superior water solubility, was used as a positive control. Results: Nic-SMEDDS (5.6% drug load) displayed favorable physicochemical properties and drug release profiles in vitro. In vivo, Nic-SMEDDS displayed prolonged retention time and plasma release profile compared to niclosamide or NEN. Oral administration of Nic-SMEDDS to non-tumor bearing mice improved niclosamide bioavailability and Cmax by 4.1- and 1.8-fold, respectively, compared to oral niclosamide. Cycloheximide pre-treatment blocked niclosamide absorption from orally administered Nic-SMEDDS, suggesting that its absorption was facilitated through the chylomicron pathway. Nic-SMEDDS (100 mg/kg, bid) showed greater anti-tumor efficacy compared to NEN (200 mg/kg, qd); this correlated with higher levels (p < 0.01) of niclosamide, increased caspase-3, and decreased Ki-67 in the harvested PDX tissues when Nic-SMEDDS was given. Biochemical analysis at the treatment end-point indicated that Nic-SMEDDS elevated lipid levels in treated mice. Conclusion: We successfully developed an orally bioavailable formulation of niclosamide, which significantly enhanced oral bioavailability and anti-tumor efficacy in an HCC PDX mouse model. Our data support its clinical translation for the treatment of solid tumors.