Novel selective inhibitors of macropinocytosis-dependent growth in pancreatic ductal carcinoma.

Macropinocytosis is a cellular process that enables cells to engulf extracellular material, such as nutrients, growth factors, and even whole cells. It is involved in several physiological functions as well as pathological conditions. In cancer cells, macropinocytosis plays a crucial role in promoting tumor growth and survival under nutrient-limited conditions. In particular KRAS mutations have been identified as main drivers of macropinocytosis in pancreatic, breast, and non-small cell lung cancers. We performed a high-content screening to identify inhibitors of macropinocytosis in pancreatic ductal adenocarcinoma (PDAC)-derived cells, aiming to prevent nutrient scavenging of PDAC tumors. The screening campaign was conducted in a well-known pancreatic KRAS-mutated cell line (MIAPaCa-2) cultured under nutrient deprivation and using FITC-dextran to precisely quantify macropinocytosis. We assembled a collection of 3584 small molecules, including drugs approved by the Food and Drug Administration (FDA), drug-like molecules against molecular targets, kinase-targeted compounds, and molecules designed to hamper protein-protein interactions. We identified 28 molecules that inhibited macropinocytosis, with potency ranging from 0.4 to 29.9 µM (EC50). A few of them interfered with other endocytic pathways, while 11 compounds did not and were therefore considered specific "bona fide" macropinocytosis inhibitors and further characterized. Four compounds (Ivermectin, Tyrphostin A9, LY2090314, and Pyrvinium Pamoate) selectively hampered nutrient scavenging in KRAS-mutated cancer cells. Their ability to impair albumin-dependent proliferation was replicated both in different 2D cell culture systems and 3D organotypic models. These findings provide a new set of compounds specifically targeting macropinocytosis, which could have therapeutic applications in cancer and infectious diseases.

RNA-binding protein HuR reprograms immune T cells and promotes oral squamous cell carcinoma.

Hu Antigen R, also known as ELAVL1 (HuR), is a key posttranscriptional regulator in eukaryotic cells. HuR overexpression promotes several malignancies, including head and neck squamous cell carcinoma (HNSCC). However, its immune dysfunction-associated tumorigenesis pathways remain unknown. We examined HuR's effects on oral malignancies and immune cell function in vitro and in vivo using oral carcinoma cells and transgenic HuR knockout (KO) mice. CRISPR/Cas9-mediated HuR deletion in mice syngeneic oral cancer cells eliminated colony formation and tumor development. HuR-KO tumors had a lower tumor volume, fewer CD4+CD25+FoxP3+ regulatory T cells, and more CD8+ T cells, suggesting that HuR may suppress the immune response during oral cancer progression. In contrast, HuR KO oral epithelial tissues are resistant to 4NQO-induced oral malignancies compared to control tumor-bearing mice. HuR KO mice showed fewer Tregs and greater IFN levels than WT tumor-bearing mice, suggesting anticancer activity. Finally, the HuR inhibitor pyrvinium pamoate lowers tumor burden by enhancing CD8+ infiltration at the expense of CD4+, suggesting anticancer benefits. Thus, HuR-dependent oral neoplasia relies on immunological dysfunction, suggesting that decreasing HuR may boost antitumor potential and offer a novel HNSCC therapy.

In Vitro and Ex Vivo Synergistic Effect of Pyrvinium Pamoate Combined with Miltefosine and Paromomycin against Leishmania.

One of the major drawbacks of current treatments for neglected tropical diseases is the low safety of the drugs used and the emergence of resistance. Leishmaniasis is a group of neglected diseases caused by protozoa of the trypanosomatidae family that lacks preventive vaccines and whose pharmacological treatments are scarce and unsafe. Combination therapy is a strategy that could solve the above-mentioned problems, due to the participation of several mechanisms of action and the reduction in the amount of drug necessary to obtain the therapeutic effect. In addition, this approach also increases the odds of finding an effective drug following the repurposing strategy. From the previous screening of two collections of repositioning drugs, we found that pyrvinium pamoate had a potent leishmanicidal effect. For this reason, we decided to combine it separately with two clinically used leishmanicidal drugs, miltefosine and paromomycin. These combinations were tested in axenic amastigotes of Leishmania infantum obtained from bone marrow cells and in intramacrophagic amastigotes obtained from primary cultures of splenic cells, both cell types coming from experimentally infected mice. Some of the combinations showed synergistic behavior, especially in the case of the combination of pyrvinium pamoate with paromomycin, and exhibited low cytotoxicity and good tolerability on intestinal murine organoids, which reveal the potential of these combinations for the treatment of leishmaniasis.

Integrative analysis reveals therapeutic potential of pyrvinium pamoate in Merkel cell carcinoma.

Merkel Cell Carcinoma (MCC) is a highly aggressive neuroendocrine cutaneous malignancy arising from either ultraviolet-induced mutagenesis or Merkel cell polyomavirus (MCPyV) integration. It is the only known neuroendocrine tumor (NET) with a virus etiology. Despite extensive research, our understanding of the molecular mechanisms driving the transition from normal cells to MCC remains limited. To address this knowledge gap, we assessed the impact of inducible MCPyV T antigens into normal human fibroblasts by performing RNA sequencing. Our findings suggested that the WNT signaling pathway plays a critical role in the development of MCC. To test this model, we bioinformatically evaluated various perturbagens for their ability to reverse the MCC gene expression signature and identified pyrvinium pamoate, an FDA-approved anthelminthic drug known for its anti-tumor potential in multiple cancers. Leveraging transcriptomic, network, and molecular analyses, we found that pyrvinium effectively targets multiple MCC vulnerabilities. Specifically, pyrvinium not only reverses the neuroendocrine features of MCC by modulating canonical and non-canonical WNT signaling pathways but also inhibits cancer cell growth by activating the p53-mediated apoptosis pathway, disrupting mitochondrial function, and inducing endoplasmic reticulum (ER) stress. Pyrvinium also effectively inhibits tumor growth in an MCC mouse xenograft model. These findings offer new avenues for the development of therapeutic strategies for neuroendocrine cancer and highlight the utility of pyrvinium as a potential treatment for MCC.

A Mouse Model for the Rapid and Binomial Assessment of Putative WNT/ß-Catenin Signalling Inhibitors.

Specific signalling thresholds of the WNT/ß-catenin pathway affect embryogenesis and tissue homeostasis in the adult, with mutations in this pathway frequently occurring in cancer. Excessive WNT/ß-catenin activity inhibits murine anterior development associated with embryonic lethality and accounts for the driver event in 80% of human colorectal cancers. Uncontrolled WNT/ß-catenin signalling arises primarily from impairment mutation in the tumour suppressor gene APC that otherwise prevents prolonged stabilisation of ß-catenin. Surprisingly, no inhibitor compounds for WNT/ß-catenin signalling have reached clinical use in part owing to the lack of specific in vivo assays that discriminate between on-target activities and dose-limiting toxicities. Here, we present a simple in vivo assay with a binary outcome whereby the administration of candidate compounds to pregnant and phenotypically normal Apcflox/flox mice can rescue in utero death of Apcmin/flox mutant conceptus without subsequent post-mortem assessment of WNT/ß-catenin signalling. Indeed, the phenotypic plasticity of born Apcmin/flox conceptus enables future refinement of our assay to potentially enable dosage finding and cross-compound comparisons. Thus, we show for the first time the suitability of endogenous WNT/ß-catenin signalling during embryonic development to provide an unambiguous and sensitive mammalian in vivo model to assess the efficacy and bioavailability of potential WNT/ß-catenin antagonists.

Metabolic modulation of mitochondrial mass during CD4+ T cell activation.

Mitochondrial biogenesis initiates within hours of T cell receptor (TCR) engagement and is critical for T cell activation, function, and survival; yet, how metabolic programs support mitochondrial biogenesis during TCR signaling is not fully understood. Here, we performed a multiplexed metabolic chemical screen in CD4+ T lymphocytes to identify modulators of metabolism that impact mitochondrial mass during early T cell activation. Treatment of T cells with pyrvinium pamoate early during their activation blocks an increase in mitochondrial mass and results in reduced proliferation, skewed CD4+ T cell differentiation, and reduced cytokine production. Furthermore, administration of pyrvinium pamoate at the time of induction of experimental autoimmune encephalomyelitis, an experimental model of multiple sclerosis in mice, prevented the onset of clinical disease. Thus, modulation of mitochondrial biogenesis may provide a therapeutic strategy for modulating T cell immune responses.

Synergistic effect of pyrvinium pamoate and posaconazole against Cryptococcus neoformans in vitro and in vivo.

Background: Cryptococcosis is a global invasive mycosis with high rates of morbidity and mortality, especially in AIDS patients. Its treatment remains challenging because of the limited antifungals and their unavoidable toxicity, and as such more efforts need to focus on the development of novel effective drugs. Previous studies have indicated that pyrvinium pamoate (PP) has individual and synergistic fungistatic effect. In this study, the effects of PP alone and in combination with azoles [fluconazole (FLU), itraconazole (ITR), voriconazole (VOR), posaconazole (POS)] or amphotericin B (AmB) were evaluated against Cryptococcus neoformans both in vitro and in vivo. Methods: A total of 20 C. neoformans strains collected from cryptococcal pneumonia and cryptococcal meningitis were studied. The effects of PP alone, PP-azoles and PP-AmB interactions against C. neoformans were evaluated via the microdilution chequerboard technique, adapted from broth microdilution method according to the CLSI M27-A4. The in vivo antifungal activity of PP alone and in combination with azoles and AmB against C. neoformans infections was evaluated by Galleria mellonella survival assay. Results: The in vitro results revealed that PP individually was ineffective against C. neoformans (MIC>16 µg/ml). Nevertheless, the synergistic effects of PP with ITR, VOR, POS, FLU or AmB was observed in 13 (65.0%, FICI 0.188-0.365), 3 (15.0%, FICI 0.245-0.301), 19 (95.0%, FICI 0.188-0.375), 7 (35.0%, FICI 0.188-0.375), and 12(60.0%, FICI 0.281-0.375) strains of C. neoformans, respectively. There was no antagonism. The survival rates of larvae treated with PP (3.33%) showed almost no antifungal effective, but the larvae survival rates improved when PP combined with AmB (35% vs. 23.33%), FLU (40% vs. 25%), ITR (48.33% vs. 33.33%), VOR (48.33% vs. 53.33%) and POS (56.67% vs. 36.67%) comparison with AmB or azoles alone, and statistical significance was observed when PP combined with POS versus POS alone (P = 0.04). Conclusions: In summary, the preliminary results indicated the potential of PP in reduction the MICs of azoles and AmB, also itself against C. neoformans; the combination of PP with AMB, FLU, ITR, VOR and POS improve the survival rates of C. neoformans infection larvae, compared with they are alone. The in vitro and in vivo data show that PP could enhance the activity of POS against C. neoformans. This study contributes with data of PP in combination with classical drugs of choice for cryptococcosis treatment.

Pyrvinium pamoate potentiates levofloxacin against levofloxacin-resistant Staphylococcus aureus.

Background: Drug repurposing is a viable approach to expediting the tedious conventional drug discovery process, given rapidly increasing bacterial resistance. In this context, we have repurposed pyrvinium pamoate (PP) for its antibacterial activity against Staphylococcus aureus. Methods: US FDA-approved non-antibiotics were screened against clinically relevant bacterial pathogens to identify antibacterials. The hits were further evaluated utilizing a variety of preclinical parameters, following which in vivo efficacy was estimated in isolation and in combination in a murine neutropenic thigh infection model. Result: The screening identified PP exhibiting potent activity against S. aureus along with concentration-dependent killing. PP also showed a post-antibiotic effect of >22 h and significantly eradicated preformed S. aureus biofilms and intracellular S. aureus at 1× and 5× MIC, respectively. PP synergized with levofloxacin both in vitro and in vivo, resulting in ∼1.5 and ∼0.5 log10 CFU/g reduction against susceptible and resistant S. aureus infections, respectively, as compared with untreated control. Conclusion: Pyrvinium potentiates levofloxacin against levofloxacin-resistant S. aureus.

Treatment of drug-resistant bacterial infections urgently requires novel antibiotic combinations that can help in reducing the dose of antibiotic required as well as decreasing the emergence of resistance. In this context, pyrvinium pamoate is active as an antibacterial against clinically drug-resistant Staphylococcus aureus and combines well with levofloxacin against levofloxacin-resistant S. aureus. Given the paucity of available treatments for multidrug-resistant S. aureus, this is a very welcome new addition to the antibiotic arsenal.

Pyrvinium Pamoate and Structural Analogs Are Early Macrofilaricide Leads.

Onchocerciasis and lymphatic filariasis are neglected tropical diseases caused by infection with filarial worms. Annual or biannual mass drug administration with microfilaricidal drugs that kill the microfilarial stages of the parasites has helped reduce infection rates and thus prevent transmission of both infections. However, success depends on high population coverage that is maintained for the duration of the adult worm's lifespan. Given that these filarial worms can live up to 14 years in their human hosts, a macrofilaricidal drug would vastly accelerate elimination efforts. Here, we have evaluated the repurposed drug pyrvinium pamoate as well as newly synthesized analogs of pyrvinium for their efficacy against filarial worms in vitro and in vivo. We found that pyrvinium pamoate, tetrahydropyrvinium and one of the analogs were highly potent in inhibiting worms in in vitro whole-worm screening assays, and that all three compounds reduced female worm fecundity and inhibited embryogenesis in the Brugia pahangi-gerbil in vivo model of infection.

Pyrvinium pamoate ameliorates cyclosporin A- induced hepatotoxicity via the modulation of Wnt/ß-catenin signaling and upregulation of PPAR-γ.

BACKGROUND: Cyclosporin A (CsA) is an immunosuppressive agent that can be used to treat autoimmune diseases. Despite its hepatotoxicity, CsA is a backbone in organ transplantation. Pyrvinium pamoate (PP) is an inhibitor of Wnt signaling approved by the U.S. Food and Drug Administration for its anthelmintic properties. AIM: The goal of this investigation was to determine whether PP could protect against CsA-induced hepatotoxicity. METHOD: Five groups of 50 albino male mice were selected and divided into five groups; group 1 was the control, groups 2 to 4 were subjected to daily CsA (25 mg/kg, i.p), in which groups 3 and 4 were treated with graded dose of PP (0.25, 0.5 mg/kg), and group 5 was treated with PP (0.5 mg/ kg) for 21 days. The mice were sacrificed under anesthesia, and their livers were removed for histological and biochemical assessment. RESULTS: CsA was found to cause a striking increase in liver enzymes, total bilirubin, and malondialdehyde levels while significantly decreasing the levels of albumin, glutathione, and antioxidant enzymes in the treated groups. The tissue levels of tumor necrosis factor-α, interleukin-1ß, and NFКB were also significantly higher with CsA treatment. Moreover, CsA triggered a notable increase in the levels of apoptotic marker P53. CsA activated the Wnt/ß-catenin pathway by increasing WNT3a expression, frizzled receptor-7, ß-catenin, and c-myc. On the other hand, the levels of PPAR-γ decreased significantly with CsA. CsA-induced alterations in the previously stated parameters were greatly reduced by PP, indicating its antioxidant, anti-inflammatory, and antiapoptotic properties. CONCLUSIONS: PP may be considered as a promising agent to prevent CsA hepatotoxicity.

Cancer as an infectious disease: A different treatment alternative using a combination of tigecycline and pyrvinium pamoate - An example of breast cancer.

BACKGROUND: Tigecycline is an antibiotic that well tolerated for treating complicated infections. It has received attention as an anti-cancer agent and expected to solve two major obstacles, sides effects that accompany chemotherapy and drug resistance, in the breast cancer treatment. However, previous studies reported that the levels in the blood are typically low of tigecycline, so higher doses are needed to treat cancer, that may increase the risk of side effects. To achieve better anti-cancer effects for tigecycline, we need to find a novel adjunct agent. METHODS: In this study, we used different concentration of pyrvinium pamoate combined with tigecycline to treat cell. And assess the effect of two drugs in inhibit cell proliferation, induce cell autophagy, or increase cell apoptosis to evaluate the consequent of combined therapy. RESULTS: We observed that after the combined therapy, the cell cycle arrest at G1/s phase, the level of p21 increased, but decreased the levels of CDK2. Others, two drugs via different mechanisms to inhibit cancer cell proliferation and with selective cytotoxic to different cell lines. That could enhance the effect of breast cancer treatment. CONCLUSION: Combining low dose of tigecycline use with pyrvinium pamoate is a novel approach for breast cancer treatment. Appropriate combined therapy in breast cancer is recommended to improve outcomes. Other problems like drug resistance occur in patients or the microbes surrounding breast tissues would confer susceptibility to cancers then influence the effectiveness of treatment, which could be improved through combined therapy.

Deciphering the Role of Pyrvinium Pamoate in the Generation of Integrated Stress Response and Modulation of Mitochondrial Function in Myeloid Leukemia Cells through Transcriptome Analysis.

Pyrvinium pamoate, a widely-used anthelmintic agent, reportedly exhibits significant anti-tumor effects in several cancers. However, the efficacy and mechanisms of pyrvinium against myeloid leukemia remain unclear. The growth inhibitory effects of pyrvinium were tested in human AML cell lines. Transcriptome analysis of Molm13 myeloid leukemia cells suggested that pyrvinium pamoate could trigger an unfolded protein response (UPR)-like pathway, including responses to extracellular stimulus [p-value = 2.78 × 10-6] and to endoplasmic reticulum stress [p-value = 8.67 × 10-7], as well as elicit metabolic reprogramming, including sulfur compound catabolic processes [p-value = 2.58 × 10-8], and responses to a redox state [p-value = 5.80 × 10-5]; on the other hand, it could elicit a pyrvinium blunted protein folding function, including protein folding [p-value = 2.10 × 10-8] and an ATP metabolic process [p-value = 3.95 × 10-4]. Subsequently, pyrvinium was verified to induce an integrated stress response (ISR), demonstrated by activation of the eIF2α-ATF4 pathway and inhibition of mTORC1 signaling, in a dose- and time-dependent manner. Additionally, pyrvinium could co-localize with mitochondria and then decrease the mitochondrial basal oxidative consumption rate, ultimately dysregulating the mitochondrial function. Similar effects were observed in cabozantinib-resistant Molm13-XR cell lines. Furthermore, pyrvinium treatment retarded Molm13 and Molm13-XR xenograft tumor growth. Thus, we concluded that pyrvinium exerts anti-tumor activity, at least, via the modulation of the mitochondrial function and by triggering ISR.

Lipidomic Analyses Uncover Apoptotic and Inhibitory Effects of Pyrvinium Pamoate on Cholangiocarcinoma Cells via Mitochondrial Membrane Potential Dysfunction.

Pyrvinium pamoate (PP), an FDA-approved anthelmintic drug, has been validated as a highly potent anti-cancer agent and patented recently as a potential chemotherapeutic drug for various cancers. The aims of this study were, therefore, to investigate the ability of PP in anti-proliferative activity and focused on the lipid profiles revealing the alteration of specific lipid species in the liver fluke Opisthorchis viverrini (Ov)-associated cholangiocarcinoma (CCA) cells. PP inhibited CCA cell viability through suppressing mitochondrial membrane potential (MMP) and ATP productions, leading to apoptotic cell death. Liquid chromatography-mass spectrometry combined with chemometrics was performed to investigate lipid alteration during PP-induced apoptosis. The lipidomic analyses showed the altered lipid signatures of CCA cell types including S-acetyldihydrolipoamide, methylselenopyruvate, and triglycerides that were increased in PP-treated CCA cells. In contrast, the levels of sphinganine and phosphatidylinositol were lower in the PP-treated group compared with its counterpart. The orthogonal partial-least squares regression analysis revealed that PP-induced MMP dysfunction, leading to remarkably reduced ATP level, was significantly associated with triglyceride (TG) accumulation observed in PP-treated CCA cells. Our findings indicate that PP could suppress the MMP function, which causes inhibition of CCA cell viability through lipid production, resulting in apoptotic induction in CCA cells. These findings provide an anti-cancer mechanism of PP under apoptotic induction ability that may serve as the alternative approach for CCA treatment.

Pyrvinium pamoate can overcome artemisinin's resistance in anaplastic thyroid cancer.

BACKGROUND: Anaplastic thyroid carcinoma is a highly lethal subtype of thyroid cancer without effective therapies. Drug resistance in anaplastic thyroid carcinoma poses a significant problem. Although artemisinin exerts antitumor effects, but its efficacy in anaplastic thyroid carcinoma is unknown. METHODS: We used RNA sequencing to identify differentially expressed genes. Next, we determined the cause of ART resistance by testing the expression and activity of ß-catenin, and enhanced ART activity with a WNT signaling inhibitor. RESULTS: Artemisinin suppressed the growth of BHT-101 but not human thyroid anaplastic carcinoma (CAL-62) cells. The mechanism of artemisinin resistance in CAL-62 was associated with the aberrant activation of WNT signaling. Pyrvinium pamoate, an inhibitor of WNT signaling, was used to overcome ART resistance in CAL-62 cells. The combination of artemisinin and pyrvinium pamoate suppressed the growth of CAL-62 cells and induced the apoptosis. CONCLUSIONS: Our study is the first to prove the efficacy of ART as monotherapy or in combination with PP in the management of anaplastic thyroid cancer, and that the inhibition of WNT signaling may overcome ART resistance.

High-throughput drug screening reveals Pyrvinium pamoate as effective candidate against pediatric MLL-rearranged acute myeloid leukemia.

Pediatric MLL-rearranged acute myeloid leukemia (AML) has a generally unfavorable outcome, primarily due to relapse and drug resistance. To overcome these difficulties, new therapeutic agents are urgently needed. Yet, implementing novel drugs for clinical use is a time-consuming, laborious, costly and high-risk process. Therefore, we applied a drug-repositioning strategy by screening drug libraries, comprised of >4000 compounds that are mostly FDA-approved, in a high-throughput format on primary MLL-rearranged AML cells. Here we identified pyrvinium pamoate (pyrvinium) as a novel candidate drug effective against MLL-rearranged AML, eliminating all cell viability at <1000 nM. Additional screening of identified drug hits on non-leukemic bone marrow samples, resulted in a decrease in cell viability of ∼50% at 1000 nM pyrvinium, suggesting a therapeutic window for targeting leukemic cells specifically. Validation of pyrvinium on an extensive panel of AML cell lines and primary AML samples showed comparable viabilities as the drug screen data, with pyrvinium achieving IC50 values of <80 nM in these samples. Remarkably, pyrvinium also induced cell toxicity in primary MLL-AF10+ AML cells, an MLL-rearrangement associated with a poor outcome. While pyrvinium is able to inhibit the Wnt pathway in other diseases, this unlikely explains the efficacy we observed as ß-catenin was not expressed in the AML cells tested. Rather, we show that pyrvinium co-localized with the mitochondrial stain in cells, and hence may act by inhibiting mitochondrial respiration. Overall, this study shows that pyrvinium is highly effective against MLL-rearranged AML in vitro, and therefore represents a novel potential candidate for further studies in MLL-rearranged AML.

Pyrvinium pamoate induces in-vitro suppression of IL-6 and IL-8 produced by human endometriotic stromal cells.

Endometriosis, a chronic inflammatory disease, is identified by the presence of endometrial tissue outside the uterus. The prevalence of this disease among reproductive-age women is almost 10-15%. High levels of IL-6 and IL-8 have been found in the peritoneal fluid (PF) of women with endometriosis and are involved in its pathogenesis. Isolated stromal cells from 12 ectopic and eutopic endometrial biopsies of women with ovarian endometrioma and also 12 endometrial biopsies of nonendometriotic controls were treated with 1.1 µM pyrvinium pamoate, a Wnt/ß-catenin signaling pathway inhibitor, for 72 hrs. Before treatment, mRNA gene expression and secretion of IL-6 and IL-8 were significantly higher in ectopic (EESCs) than eutopic (EuESCs) and control (CESCs) endometrial stromal cells. After treatment, mRNA gene expression and also secretion of IL-6 and IL-8 were significantly reduced. Our Findings showed that pyrvinium pamoate suppresses the mRNA gene expression and secretion of IL-6 and IL-8 in human endometriotic stromal cells. Additional investigations on this compound are required before clinical application.

Effect of the anti-parasitic compounds pyrvinium pamoate and artemisinin in enzymatic and culture assays: Data on the search for new anti-echinococcal drugs.

The dataset presented herein is related to a previous research article titled "Mitochondrial Complex III in Larval Stage of Echinococcus multilocularis as a Potential Chemotherapeutic Target and in vivo Efficacy of Atovaquone Against Primary Hydatid Cysts" [1]. In this report, data were collected by screening drugs for echinococcosis. We investigated the inhibitory activities of artemisinin and pyrvinium pamoate against the mitochondrial respiratory enzymes in E. multilocularis protoscoleces. Artemisinin did not inhibit mitochondrial complexes I, II, and III. However, pyrvinium pamoate inhibited complex I at 11 µM, although complexes II and III were not inhibited. In the culture assay, E. multilocularis protoscoleces were treated with atovaquone (ATV), rotenone, praziquantel, artemisinin, and pyrvinium pamoate at a final concentration of 50 µM in different culture media. The viability of protoscoleces was compared under aerobic and anaerobic conditions via culture experiments. The survival days of E. multilocularis protoscoleces were evaluated in the drug-treated group compared with those in the non-treated group. The results of these culture assays revealed that praziquantel and artemisinin did not eliminate the protoscoleces under both aerobic and anaerobic conditions. However, a stronger elimination ability was observed with the co-administration of praziquantel or artemisinin with ATV than with ATV alone under aerobic conditions. Pyrvinium pamoate completely killed protoscoleces at 5 and 7 days under aerobic and anaerobic conditions, respectively. Pyrvinium pamoate behaved identically to rotenone, the complex I inhibitor, in the culture treatment assay. The data serve as a reference for the development of novel anti-echinococcal drugs.

Repurposing FDA approved drugs inhibiting mitochondrial function for targeting glioma-stem like cells.

Glioblastoma Multiforme (GBM) tumors contain a small population of glioma stem-like cells (GSCs) among the various differentiated GBM cells (d-GCs). GSCs drive tumor recurrence, and resistance to Temozolomide (TMZ), the standard of care (SoC) for GBM chemotherapy. In order to investigate a potential link between GSC specific mitochondria function and SoC resistance, two patient-derived GSC lines were evaluated for differences in their mitochondrial metabolism. In both the lines, GSCs had significantly lower mitochondrial -content, and -function compared to d-GCs. In vitro, the standard mitochondrial-specific inhibitors oligomycin A, antimycin A, and rotenone selectively inhibited GSC proliferation to a greater extent than d-GCs and human primary astrocytes. These findings indicate that mitochondrial inhibition can be a potential GSC-targeted therapeutic strategy in GBM with minimal off-target toxicity. Mechanistically the standard mitochondrial inhibitors elicit their GSC-selective cytotoxic effects through the induction of apoptosis or autophagy pathways. We tested for GSC proliferation in the presence of 3 safe FDA-approved drugs--trifluoperazine, mitoxantrone, and pyrvinium pamoate, all of which are also known mitochondrial-targeting agents. The SoC GBM therapeutic TMZ did not trigger cytotoxicity in glioma stem cells, even at 100 µM concentration. By contrast, trifluoperazine, mitoxantrone, and pyrvinium pamoate exerted antiproliferative effects in GSCs about 30-50 fold more effectively than temozolomide. Thus, we hereby demonstrate that FDA-approved mitochondrial inhibitors induce GSC-selective cytotoxicity, and targeting mitochondrial function could present a potential therapeutic option for GBM treatment.

In vitro and in vivo Study of Antifungal Effect of Pyrvinium Pamoate Alone and in Combination With Azoles Against Exophiala dermatitidis.

Infections of Exophiala dermatitidis are often chronic and recalcitrant. Combination therapies with novel compounds and azoles could be an effective solution. Previously, we have demonstrated that pyrvinium pamoate exerted antifungal activity alone and favorable synergy with azoles against planktonic E. dermatitidis. Herein, the underlying antifungal mode of action were investigated. Pyrvinium alone showed sessile MIC50 (SMIC50) of 8->16 µg/ml against E. dermatitidis biofilms. However, synergism of PP with itraconazole, voriconazole, and posaconazole were observed against 16 (88.9%), 9 (50%), and 13 (72.2%) strains of E. dermatitidis biofilms. In accordance with in vitro susceptibilities, pyrvinium alone at concentration of 2 µg/ml resulted in significant growth restriction of planktonic E. dermatitidis. Pyrvinium alone resulted in reduction of biofilm formation. Higher concentration of pyrvinium was associate with more progressive reduction of biofilm mass. The in vivo activity of pyrvinium alone and combined with azoles was evaluated using Galleria mellonella model. Pyrvinium alone significantly improved the survival rate of larvae (P < 0.0001). The combination of pyrvinium and voriconazole or posaconazole acted synergistically in vivo (P < 0.05). Fungal burden determination revealed significant reduction of numbers of colony forming unit (CFU) in larvae treated with pyrvinium-itraconazole and pyrvinium-posaconazole compared to itraconazole or posaconazole alone group, respectively. The effect of pyrvinium on apoptosis, expression of TOR and HSP90, and drug efflux reversal were evaluated by PI/Annexin V staining, Real-Time Quantitative PCR and Rhodamine 6G assay, respectively. Pyrvinium alone or combined with azoles significantly (P < 0.05) increased late apoptosis or necrosis of E. dermatitidis cells. Pyrvinium combined with posaconazole significantly decreased the expression of TOR and Hsp90 compared to posaconazole alone group (P < 0.05). Pyrvinium resulted in significant (P < 0.05) decrease of the efflux of Rhodamine 6G. These findings suggested pyrvinium could be a promising synergist with azoles. The underlying mechanisms could be explained by inducing apoptosis/necrosis, inhibition of drug efflux pumps, and signaling pathways related with stress response and growth control.

Effects of anthelmintics on the pinworm Blatticola blattae in laboratory-reared German cockroaches Blattella germanica.

The efficacy of pyrantel pamoate, pyrvinium pamoate, ivermectin, and piperazine citrate against pinworm in cockroach was evaluated. Laboratory-reared German cockroaches naturally infected with Blatticola blattae were treated with the anthelmintics and necropsied at 3 to 35 days after treatment. Ivermectin at over 5 ppm and piperazine citrate at over 2000 ppm killed all the treated cockroaches. Pinworms were still detected in cockroaches given lower concentration of the aforementioned drugs. Administration of pyrantel pamoate (100-1000 ppm) and pyrvinium pamoate (2000 ppm) did not kill the cockroaches, and no pinworms were detected at 3 and 17 days after treatment. Thus, pyrantel pamoate and pyrvinium pamoate were found to be effective for deworming B. blattae in the German cockroaches, without causing mortality for the host. Our results showed that anthelmintics selection is essential for eradication of pinworms in cockroaches because of the toxicity for the host such as ivermectin or piperazine citrate. This is the first report of piperazine citrate toxicity in cockroaches.