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.

The FDA-Approved Anthelmintic Pyrvinium Pamoate Inhibits Pancreatic Cancer Cells in Nutrient-Depleted Conditions by Targeting the Mitochondria.

Pancreatic ductal adenocarcinoma (PDAC) is a lethal aggressive cancer, in part due to elements of the microenvironment (hypoxia, hypoglycemia) that cause metabolic network alterations. The FDA-approved antihelminthic pyrvinium pamoate (PP) has previously been shown to cause PDAC cell death, although the mechanism has not been fully determined. We demonstrated that PP effectively inhibited PDAC cell viability with nanomolar IC50 values (9-93 nmol/L) against a panel of PDAC, patient-derived, and murine organoid cell lines. In vivo, we demonstrated that PP inhibited PDAC xenograft tumor growth with both intraperitoneal (IP; P < 0.0001) and oral administration (PO; P = 0.0023) of human-grade drug. Metabolomic and phosphoproteomic data identified that PP potently inhibited PDAC mitochondrial pathways including oxidative phosphorylation and fatty acid metabolism. As PP treatment reduced oxidative phosphorylation (P < 0.001), leading to an increase in glycolysis (P < 0.001), PP was 16.2-fold more effective in hypoglycemic conditions similar to those seen in PDAC tumors. RNA sequencing demonstrated that PP caused a decrease in mitochondrial RNA expression, an effect that was not observed with established mitochondrial inhibitors rotenone and oligomycin. Mechanistically, we determined that PP selectively bound mitochondrial G-quadruplexes and inhibited mitochondrial RNA transcription in a G-quadruplex-dependent manner. This subsequently led to a 90% reduction in mitochondrial encoded gene expression. We are preparing to evaluate the efficacy of PP in PDAC in an IRB-approved window-of-opportunity trial (IND:144822).

Pyrvinium pamoate attenuates non-alcoholic steatohepatitis: Insight on hedgehog/Gli and Wnt/ß-catenin signaling crosstalk.

Non-alcoholic steatohepatitis (NASH) is a devastating form of non-alcoholic fatty liver disease (NAFLD). Pyrvinium pamoate (PP) has been recently introduced as anti-adipogenic compound. We aimed to investigate the effects of PP on high fat diet (HFD)-induced NASH in rats and examine the underlying mechanisms. NASH was induced by exposing rats to HFD for 16 weeks and a single dose of streptozotocin (STZ) 35 mg/kg at the fifth week. At the tenth week, PP was given orally at a dose of 60 µg/kg, day after day for 6 weeks. HFD/STZ induced significant steatohepatitis and insulin resistance as was evident by the elevated transaminases activity, NAFLD activity score and HOMA-IR level. Also, HFD induced serum hyperlipidemia and hepatic lipid accumulation. In addition, HFD induced an imbalance in the oxidative status of the liver via upregulating lipid peroxides and mitochondrial oxidative stress markers (MnSOD, UCP-2), together with marked decrease in anti-oxidant glutathione level, glutathione peroxidase activity and expression of mitophagy related markers (PINK1, Parkin, ULK1) and increase in SQSTM1/p62 and LC3II/LC3I. Upregulation of inflammatory mediators (TNF-α, IL-6, IL-1ß) and apoptotic marker (caspase 3) were observed. Those events all together precipitated in initiation of liver fibrosis as confirmed by elevation of transforming growth factor-ß1 (TGF-ß1), alpha-smooth muscle actin (α-SMA) and liver collagen content. Co-treatment with PP protected against HFD-induced NASH and liver fibrosis via downregulating the expression of key factors in Hedgehog and Wnt/ ß-catenin signaling pathway. These findings imply that PP can attenuate the progression of NASH and its associated sequela of liver fibrosis.

Targeting the CK1α/CBX4 axis for metastasis in osteosarcoma.

Osteosarcoma, an aggressive malignant cancer, has a high lung metastasis rate and lacks therapeutic target. Here, we reported that chromobox homolog 4 (CBX4) was overexpressed in osteosarcoma cell lines and tissues. CBX4 promoted metastasis by transcriptionally up-regulating Runx2 via the recruitment of GCN5 to the Runx2 promoter. The phosphorylation of CBX4 at T437 by casein kinase 1α (CK1α) facilitated its ubiquitination at both K178 and K280 and subsequent degradation by CHIP, and this phosphorylation of CBX4 could be reduced by TNFα. Consistently, CK1α suppressed cell migration and invasion through inhibition of CBX4. There was a reverse correlation between CK1α and CBX4 in osteosarcoma tissues, and CK1α was a valuable marker to predict clinical outcomes in osteosarcoma patients with metastasis. Pyrvinium pamoate (PP) as a selective activator of CK1α could inhibit osteosarcoma metastasis via the CK1α/CBX4 axis. Our findings indicate that targeting the CK1α/CBX4 axis may benefit osteosarcoma patients with metastasis.

Identification of pyrvinium pamoate as an anti-tuberculosis agent in vitro and in vivo by SOSA approach amongst known drugs.

Tuberculosis (TB), caused by Mycobacterium tuberculosis (M.tb) bacteria, is a leading infectious cause of mortality worldwide. The emergence of drug-resistant M. tb has made control of TB more difficult. The selective optimization of side activities (SOSA) approach uses old drugs for new pharmacological targets. In the present study by using SOSA approach, we have successfully identified pyrvinium pamoate (PP) which is capable of inhibiting the growth of mycobacteria, including M. tb H37Rv, Mycobacterium smegmatis, Bacille Calmette-Guérin (BCG), M. tb H37Ra, and drug-resistant M. tb clinical isolates in vitro from 1280 known drugs library. The MIC99 of PP, the minimum inhibitory concentration that inhibits more than 99% of M. tb H37Rv and the drug-resistant M. tb clinical isolates, ranges from 1.55 to 4.8 µg/mL. Importantly, PP could reduce the bacterial colony-forming units (CFUs) in lung, spleen and liver tissues, and effectively inhibit inflammatory response in M. tb H37Rv, multidrug-resistant (MDR) M. tb and extensively drug-resistant (XDR) M.tb-infected mice. Our results clearly show that the PP has the potential application for treatment of TB.

Possible repurposing of pyrvinium pamoate for the treatment of mesothelioma: A pre-clinical assessment.

Malignant mesothelioma (MM) is a very aggressive asbestos-related cancer, whose incidence is increasing worldwide. Unfortunately, no effective therapies are currently available and the prognosis is extremely poor. Recently, the anti-helminthic drug pyrvinium pamoate has attracted a strong interest for its anti-cancer activity, which has been demonstrated in many cancer models. Considering the previously established inhibitory effect of pyrvinium pamoate on the Wnt/ß-catenin pathway and given the important role of this pathway in MM, we investigated the potential anti-tumor activity of this drug in MM cell lines. We observed that pyrvinium pamoate significantly impairs MM cell proliferation, cloning efficiency, migration, and tumor spheroid formation. At the molecular level, our data show that pyrvinium pamoate down-regulates the expression of ß-catenin and Wnt-regulates genes. Overall, our study suggests that the repurposing of pyrvinium pamoate for MM treatment could represent a new promising therapeutic approach.

The novel role of pyrvinium in cancer therapy.

Pyrvinium pamoate (PP) is a quinoline-derived cyanine dye which was officially approved by FDA for its anthelmintic properties and therapeutic function against animal-like protists such as Cryptosporidium parvum and Plasmodium falciparum in the 1950s. In the last 10 years, several studies have shown the novel activity of pyrvinium in tumor therapy. Some investigations have indicated that pyrvinium could delay or inhibit tumor cell proliferation in cancer models including colon, breast, lung and prostate cancer, and some hematological malignancies. In this review, we discuss multiple critical signaling pathways and mechanisms underlying the anticancer effects of PP. In details, pyrvinium acts through the following main mechanisms: (i) energy and autophagy depletion; and (ii) inhibition of Akt and Wnt-ß-catenin-dependent pathways. Interestingly, pyrvinium has also shown potent anti-cancer stem cell activity. The overwhelming insights into the mechanism of anticancer properties of PP can help establishing novel and future anti-tumor treatment strategies.

Reversal of cancer gene expression correlates with drug efficacy and reveals therapeutic targets.

The decreasing cost of genomic technologies has enabled the molecular characterization of large-scale clinical disease samples and of molecular changes upon drug treatment in various disease models. Exploring methods to relate diseases to potentially efficacious drugs through various molecular features is critically important in the discovery of new therapeutics. Here we show that the potency of a drug to reverse cancer-associated gene expression changes positively correlates with that drug's efficacy in preclinical models of breast, liver and colon cancers. Using a systems-based approach, we predict four compounds showing high potency to reverse gene expression in liver cancer and validate that all four compounds are effective in five liver cancer cell lines. The in vivo efficacy of pyrvinium pamoate is further confirmed in a subcutaneous xenograft model. In conclusion, this systems-based approach may be complementary to the traditional target-based approach in connecting diseases to potentially efficacious drugs.

Computational drugs repositioning identifies inhibitors of oncogenic PI3K/AKT/P70S6K-dependent pathways among FDA-approved compounds.

The discovery of inhibitors for oncogenic signalling pathways remains a key focus in modern oncology, based on personalized and targeted therapeutics. Computational drug repurposing via the analysis of FDA-approved drug network is becoming a very effective approach to identify therapeutic opportunities in cancer and other human diseases. Given that gene expression signatures can be associated with specific oncogenic mutations, we tested whether a "reverse" oncogene-specific signature might assist in the computational repositioning of inhibitors of oncogenic pathways. As a proof of principle, we focused on oncogenic PI3K-dependent signalling, a molecular pathway frequently driving cancer progression as well as raising resistance to anticancer-targeted therapies. We show that implementation of "reverse" oncogenic PI3K-dependent transcriptional signatures combined with interrogation of drug networks identified inhibitors of PI3K-dependent signalling among FDA-approved compounds. This led to repositioning of Niclosamide (Niclo) and Pyrvinium Pamoate (PP), two anthelmintic drugs, as inhibitors of oncogenic PI3K-dependent signalling. Niclo inhibited phosphorylation of P70S6K, while PP inhibited phosphorylation of AKT and P70S6K, which are downstream targets of PI3K. Anthelmintics inhibited oncogenic PI3K-dependent gene expression and showed a cytostatic effect in vitro and in mouse mammary gland. Lastly, PP inhibited the growth of breast cancer cells harbouring PI3K mutations. Our data indicate that drug repositioning by network analysis of oncogene-specific transcriptional signatures is an efficient strategy for identifying oncogenic pathway inhibitors among FDA-approved compounds. We propose that PP and Niclo should be further investigated as potential therapeutics for the treatment of tumors or diseases carrying the constitutive activation of the PI3K/P70S6K signalling axis.

Inhibiting cytoplasmic accumulation of HuR synergizes genotoxic agents in urothelial carcinoma of the bladder.

HuR, an RNA-binding protein, post-transcriptionally regulates nearly 4% of encoding proteins implicated in cell survival. Here we show that HuR is required for the efficacy of chemotherapies in urothelial carcinoma of the bladder. We identify pyrvinium pamoate, an FDA-approved anthelminthic drug, as a novel HuR inhibitor that dose-dependently inhibited cytoplasmic accumulation of HuR. Combining pyrvinium pamoate with chemotherapeutic agents (e.g. cisplatin, doxorubicin, vincristine and oxaliplatin) not only led to enhanced cytotoxicity in bladder cancer cells but also synergistically suppressed the growth of patient-derived bladder tumor xenografts in mice (P < 0.001). Mechanistically, pyrvinium pamoate promoted nuclear import of HuR by activating the AMP-activated kinase/importin α1 cascade and blocked HuR nucleo-cytoplasmic translocation by inhibiting the checkpoint kinase1/cyclin-dependent kinase 1 pathway. Notably, pyrvinium pamoate-additive treatment increased DNA double-strand breaks as indicated by elevated γH2AX expression, suggesting an involvement of DNA damage response. We further found that pyrvinium pamoate dramatically downregulated several key DNA repair genes in genotoxically-stressed cells, including DNA ligase IV and BRCA2, leading to unbearable genomic instability and cell death. Collectively, our findings are the first to characterize a clinical HuR inhibitor and provide a novel therapeutically tractable strategy by targeting cytoplasmic translocation of HuR for treatment of urothelial carcinoma of the bladder.

Birth outcomes after exposure to mebendazole and pyrvinium during pregnancy - A Danish nationwide cohort study.

Mebendazole and pyrvinium are anthelmintics used to treat infections with pinworms, a common infection in children. Other indications for treatment with mebendazole are infections with soil-transmitted helminths. These infections are rare in Denmark, but affect more than 1.5 billion people worldwide. Limited safety data of anthelmintics during pregnancy exists and the purpose of this study was to investigate the association between exposure to mebendazole or pyrvinium during pregnancy and the adverse pregnancy outcomes: congenital malformations, stillbirths, neonatal mortality and small for gestational age. The Danish Fertility Database was used to identify all births in Denmark from 1997 to 2007. Maternal exposure to anthelmintics was identified through The Danish Prescription Registry. Of 713667 births, 2567 mothers redeemed a prescription for mebendazole; 1588 for pyrvinium. Logistic regression analysis adjusted for potential confounders. We found no association between exposure to mebendazole and major congenital malformations (OR = 0.7 (CI 95% 0.5-1.1)) or other negative birth outcomes and we found no association between exposure to pyrvinium and major congenital malformations (OR = 0.8 (CI 95% 0.4-1.5)) or other negative birth outcomes. No increased risk was found of having negative birth outcomes after exposure at any trimester during pregnancy.

Pyrvinium selectively targets blast phase-chronic myeloid leukemia through inhibition of mitochondrial respiration.

The use of BCR-ABL1 tyrosine kinase inhibitors (TKI) has led to excellent clinical responses in patients with chronic phase chronic myeloid leukemia (CML). However these inhibitors have been less effective as single agents in the terminal blast phase (BP). We show that pyrvinium, a FDA-approved anthelminthic drug, selectively targets BP-CML CD34+ progenitor cells. Pyrvinium is effective in inducing apoptosis, inhibiting colony formation and self-renewal capacity of CD34+ cells from TKI-resistant BP-CML patients, while cord blood CD34+ are largely unaffected. The effects of pyrvinium are further enhanced upon combination with dasatinib, a second generation BCR-ABL1 TKI. In a CML xenograft model pyrvinium significantly inhibits tumor growth as a single agent, with complete inhibition in combination with dasatinib. While pyrvinium has been shown to inhibit the Wnt/ß-catenin signalling pathway via activation of casein kinase 1α , we find its activity in CML is not dependent on this pathway. Instead, we show that pyrvinium localizes to mitochondria and induces apoptosis by inhibiting mitochondrial respiration. Our study suggests that pyrvinium is a useful addition to the treatment armamentarium for BP-CML and that targeting mitochondrial respiration may be a potential therapeutic strategy in aggressive leukemia.

The impact of pyrvinium pamoate on colon cancer cell viability.

PURPOSE: The in vitro and in vivo effects of pyrvinium pamoate (PP), a newly identified WNT signaling inhibitor, were evaluated against colon cancer cell lines and primary colon cancer samples. EXPERIMENTAL DESIGN: Antiproliferative activity of PP and its effects on protein and RNA levels of WNT targets were evaluated on adenomatous polyposis coli (APC (mut)) and ß-catenin(mut) cell lines, one WNT(wt) colon cancer cell line, as well as six primary colon cancer samples with mutant APC in vitro. In addition, the effect of PP on the growth of liver metastasis was examined. RESULTS: PP blocked colon cancer cell growth in vitro in a dose-dependent manner with great differences in the inhibitory concentration (IC(50)), ranging from 0.6 × 10(-6) to 65 × 10(-6) mol/L for colon cancer cells with mutations in WNT signaling. In addition, PP demonstrated a cytotoxic effect on primary colon cancer samples. A combined cytotoxic effect of PP with 5-fluorouracil (5-FU) was observed for two cell lines. PP decreased messenger RNA (mRNA) and protein levels of known WNT target genes as c-MYC and thereby led to the induction of p21. PP inhibited the migration of HCT116 colon cancer cells in vitro and decreased tumor growth in vivo after intraportal injection of HCT116 cells in nude mice. CONCLUSIONS: PP displays promising anticancer activity against a broad panel of human colon cancer cell lines, as well as primary colon cancer samples. However, our findings do not demonstrate a predominant cytotoxic effect of PP on colon cancer cells with mutations in WNT signaling.

Ligand-independent and tissue-selective androgen receptor inhibition by pyrvinium.

Pyrvinium pamoate (PP) is a potent noncompetitive inhibitor of the androgen receptor (AR). Using a novel method of target identification, we demonstrate that AR is a direct target of PP in prostate cancer cells. We demonstrate that PP inhibits AR activity via the highly conserved DNA binding domain (DBD), the only AR inhibitor that functions via this domain. Furthermore, computational modeling predicts that pyrvinium binds at the interface of the DBD dimer and the minor groove of the AR response element. Because PP acts through the DBD, PP is able to inhibit the constitutive activity of AR splice variants, which are thought to contribute to the growth of castration resistant prostate cancer (CRPC). PP also inhibits androgen-independent AR activation by HER2 kinase. The antiandrogen activity of pyrvinium manifests in the ability to inhibit the in vivo growth of CRPC xenografts that express AR splice variants. Interestingly, PP was most potent in cells with endogenous AR expression derived from prostate or bone. PP was able to inhibit several other hormone nuclear receptors (NRs) but not structurally unrelated transcription factors. PP inhibition of other NRs was similarly cell-type selective. Using dual-energy X-ray absorptiometry, we demonstrate that the cell-type specificity of PP manifests in tissue-selective inhibition of AR activity in mice, as PP decreases prostate weight and bone mineral density but does not affect lean body mass. Our results suggest that the noncompetitive AR inhibitor pyrvinium has significant potential to treat CRPC, including cancers driven by ligand-independent AR signaling.

An anthelmintic drug, pyrvinium pamoate, thwarts fibrosis and ameliorates myocardial contractile dysfunction in a mouse model of myocardial infarction.

Metabolic adaptation to limited supplies of oxygen and nutrients plays a pivotal role in health and disease. Heart attack results from insufficient delivery of oxygen and nutrients to the heart, where cardiomyocytes die and cardiac fibroblasts proliferate--the latter causing scar formation, which impedes regeneration and impairs contractility of the heart. We postulated that cardiac fibroblasts survive metabolic stress by adapting their intracellular metabolism to low oxygen and nutrients, and impeding this metabolic adaptation would thwart their survival and facilitate the repair of scarred heart. Herein, we show that an anthelmintic drug, Pyrvinium pamoate, which has been previously shown to compromise cancer cell survival under glucose starvation condition, also disables cardiac fibroblast survival specifically under glucose deficient condition. Furthermore, Pyrvinium pamoate reduces scar formation and improves cardiac contractility in a mouse model of myocardial infarction. As Pyrvinium pamoate is an FDA-approved drug, our results suggest a therapeutic use of this or other related drugs to repair scarred heart and possibly other organs.

Pyrvinium targets autophagy addiction to promote cancer cell death.

Autophagy is a cellular catabolic process by which long-lived proteins and damaged organelles are degradated by lysosomes. Activation of autophagy is an important survival mechanism that protects cancer cells from various stresses, including anticancer agents. Recent studies indicate that pyrvinium pamoate, an FDA-approved antihelminthic drug, exhibits wide-ranging anticancer activity. Here we demonstrate that pyrvinium inhibits autophagy both in vitro and in vivo. We further demonstrate that the inhibition of autophagy is mammalian target of rapamycin independent but depends on the transcriptional inhibition of autophagy genes. Moreover, the combination of pyrvinium with autophagy stimuli improves its toxicity against cancer cells, and pretreatment of cells with 3-MA or siBeclin1 partially protects cells from pyrvinium-induced cell death under glucose starvation, suggesting that targeted autophagy addiction is involved in pyrvinium-mediated cytotoxicity. Finally, in vivo studies show that the combination therapy of pyrvinium with the anticancer and autophagy stimulus agent, 2-deoxy-D-glucose (2-DG), is significantly more effective in inhibiting tumor growth than pyrvinium or 2-DG alone. This study supports a novel cancer therapeutic strategy based on targeting autophagy addiction and implicates using pyrvinium as an autophagy inhibitor in combination with chemotherapeutic agents to improve their therapeutic efficacy.

Exposure to mebendazole and pyrvinium during pregnancy: a Danish nationwide cohort study.

PURPOSE: Families with children are frequently exposed to pinworm infection and treatment involves the whole family. Information on consequences of exposure during, pregnancy is limited. The aim of this study was to investigate the exposure to pyrvinium and mebendazole before, during, and after pregnancy in a Danish nationwide cohort. METHODS: From nationwide administrative registers, we identified 718,900 births in Denmark between January 1997 and December 2007 as well as maternal prescription data of anthelmintics and maternal characteristics. Redemption of a prescription for pyrvinium or mebendazole was used to identify exposure. RESULTS: 4715 women redeemed a prescription for pyrvinium or mebendazole during pregnancy; 1606 for pyrvinium, 2575 for mebendazole, and 534 for both drugs. Having >2 children compared to having no previous children was associated with exposure to pyrvinium (OR: 7.1, 95% CI: 5.8-8.7) and mebendazole (OR: 20.8, 95% CI: 17.3-24.9). CONCLUSION: 4715 pregnant women redeemed a prescription for either mebendazole or pyrvinium. We believe the exposure to be even higher since pyrvinium is also sold over-the-counter. Limited information on birth outcomes is available at present time, and considering the number of exposed pregnancies, we recommend that studies are to be undertaken to assess the safety of pyrvinium and mebendazole during pregnancy.

Pinworm and TNKS inhibitors, an eccentric duo to derail the oncogenic WNT pathway.

The WNT/ß-catenin pathway underlies many human cancers through mutations in the APC, ß-catenin, and Axin genes. Activation of WNT signalling can also occur due to the localization of glycogen synthase kinase 3ß(GSK3ß) to the multivesicular bodies, which prevents the degradation of ß-catenin. This leads to accumulation of ß-catenin within the cytoplasmic matrix and nucleus of cancer cells, which triggers the transactivation of genes involved in cell proliferation, including various oncogenes. Recent research into the mechanistic regulations of molecule homeostasis and identification of new small-targeted inhibitors has provided further insights into the WNT signalling pathway and its role in human cancers. Novel WNT inhibitors target unsuspected cellular enzymes, such as tankyrases, or casein kinase 1α/γ, which controls the destruction of ß-catenin and GSK3ß. These could lead to the identification of new biomarkers and WNT-targeted inhibitors for the treatment of cancer.

Efficacy of pyrvinium pamoate against Cryptosporidium parvum infection in vitro and in a neonatal mouse model.

No effective approved drug therapy exists for Cryptosporidium infection of immunocompromised patients. Here we investigated the nonabsorbed anthelmintic drug pyrvinium pamoate for inhibition of the growth of the intestinal protozoan parasite Cryptosporidium parvum. The concentration of pyrvinium that effected 50% growth inhibition in human enterocytic HCT-8 cells by a quantitative alkaline phosphatase immunoassay was 354 nM. For comparison, in the same assay, 50% growth inhibition was obtained with 711 microM paromomycin or 27 microM chloroquine. We used a neonatal mouse model to measure the anti-Cryptosporidium activity of pyrvinium pamoate in vivo. Beginning 3 days after infection, pyrvinium at 5 or 12.5 mg/kg of body weight/day was administered to the treatment group mice for 4 or 6 consecutive days. Nine days after infection, the mice were sacrificed, and drug efficacy was determined by comparing the numbers of oocysts in the fecal smears of treated versus untreated mice. The intensities of trophozoite infection in the ileocecal intestinal regions were also compared using hematoxylin-and-eosin-stained histological slides. We observed a >90% reduction in infection intensity in pyrvinium-treated mice relative to that in untreated controls, along with a substantial reduction in tissue pathology. Based on these results, pyrvinium pamoate is a potential drug candidate for the treatment of cryptosporidiosis in both immunocompetent and immunocompromised individuals.