A cell-based high-throughput screening method to directly examine transthyretin amyloid fibril formation at neutral pH.

Transthyretin (TTR) is a major amyloidogenic protein associated with hereditary (ATTRm) and nonhereditary (ATTRwt) intractable systemic transthyretin amyloidosis. The pathological mechanisms of ATTR-associated amyloid fibril formation are incompletely understood, and there is a need for identifying compounds that target ATTR. C-terminal TTR fragments are often present in amyloid-laden tissues of most patients with ATTR amyloidosis, and on the basis of in vitro studies, these fragments have been proposed to play important roles in amyloid formation. Here, we found that experimentally-formed aggregates of full-length TTR are cleaved into C-terminal fragments, which were also identified in patients' amyloid-laden tissues and in SH-SY5Y neuronal and U87MG glial cells. We observed that a 5-kDa C-terminal fragment of TTR, TTR81-127, is highly amyloidogenic in vitro, even at neutral pH. This fragment formed amyloid deposits and induced apoptosis and inflammatory gene expression also in cultured cells. Using the highly amyloidogenic TTR81-127 fragment, we developed a cell-based high-throughput screening method to discover compounds that disrupt TTR amyloid fibrils. Screening a library of 1280 off-patent drugs, we identified two candidate repositioning drugs, pyrvinium pamoate and apomorphine hydrochloride. Both drugs disrupted patient-derived TTR amyloid fibrils ex vivo, and pyrvinium pamoate also stabilized the tetrameric structure of TTR ex vivo in patient plasma. We conclude that our TTR81-127-based screening method is very useful for discovering therapeutic drugs that directly disrupt amyloid fibrils. We propose that repositioning pyrvinium pamoate and apomorphine hydrochloride as TTR amyloid-disrupting agents may enable evaluation of their clinical utility for managing ATTR amyloidosis.

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.

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.

Inhibitory effect of pyrvinium pamoate on uveal melanoma cells involves blocking of Wnt/ß-catenin pathway.

Uveal melanoma is the most common primary intraocular malignancy in adults. And there is an absence of targeted agents for patients with uveal melanoma. Pyrvinium pamoate is an old anthelminthic medicine approved by FDA for the treatment of enterobiasis in 1955, which recently re-attracts attention as an anti-cancer drug due to its inhibition of Wnt/ß-catenin pathway in some types of cancer. But the role of pyrvinium pamoate in uveal melanoma and the potential underlying mechanism remains unknown. In this study, we tested the anti-tumor effects of pyrvinium pamoate on four uveal melanoma cell lines (92.1, Mel270, Omm1, and Omm2.3) and evaluated the Wnt/ß-catenin signaling transduction, cell growth, cell death, cell migration, and invasion accordingly. The results revealed that pyrvinium pamoate treatment repressed the phosphorylation of GSK3ß at S9 which might be mediated by AKT, and decreased the protein levels of ß-catenin and its downstream targets (c-Myc, cyclin D1). Pyrvinium pamoate remarkably inhibited cell viability and colony formation ability. Treatment with pyrvinium pamoate induced intrinsic pathway-dependent apoptosis accompanied with a decline of anti-apoptotic XIAP and Survivin, and an overt increase of pro-apoptotic Bax. In addition, pyrvinium pamoate significantly inhibited the migration and invasion in vitro. Our studies suggest that pyrvinium pamoate may be a potential therapeutic agent for uveal melanoma.

Angiotensin II increases fibronectin and collagen I through the ß-catenin-dependent signaling in mouse collecting duct cells.

The contribution of angiotensin II (ANG II) to renal and tubular fibrosis has been widely reported. Recent studies have shown that collecting duct cells can undergo mesenchymal transition suggesting that collecting duct cells are involved in interstitial fibrosis. The Wnt/ß-catenin signaling pathway plays an essential role in development, organogenesis, and tissue homeostasis; however, the dysregulation of this pathway has been linked to fibrosis. In this study, we investigated whether AT1 receptor activation induces the expression of fibronectin and collagen I via the ß-catenin pathway in mouse collecting duct cell line M-1. ANG II (10(-7) M) treatment in M-1 cells increased mRNA, protein levels of fibronectin and collagen I, the ß-catenin target genes (cyclin D1 and c-myc), and the myofibroblast phenotype. These effects were prevented by candesartan, an AT1 receptor blocker. Inhibition of the ß-catenin degradation with pyrvinium pamoate (pyr; 10(-9) M) prevented the ANG II-induced expression of fibronectin, collagen I, and ß-catenin target genes. ANG II treatment promoted the accumulation of ß-catenin protein in a time-dependent manner. Because phosphorylation of glycogen synthase kinase-3ß (GSK-3ß) inhibits ß-catenin degradation, we further evaluated the effects of ANG II and ANG II plus pyr on p-ser9-GSK-3ß levels. ANG II-dependent upregulation of ß-catenin protein levels was correlated with GSK-3ß phosphorylation. These effects were prevented by pyr. Our data indicate that in M-1 collecting duct cells, the ß-catenin pathway mediates the stimulation of fibronectin and collagen I in response to AT1 receptor activation.

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.

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.

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.

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.

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.

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 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 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.

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.

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.

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.