The FDA-Approved Drug Pyrvinium Selectively Targets ER(+) Breast Cancer Cells with High INPP4B Expression

The majority of breast cancers are estrogen receptor-positive (ER⁺), and endocrine therapies that suppress ER signaling are the standard-of-care treatment for this subset. However, up to half of all ER⁺ cancers eventually relapse, highlighting a need for improved clinical therapies. The phosphoinositide phosphatase, INPP4B, is overexpressed in almost half of all ER⁺ breast cancers, and promotes Wnt/β-catenin signaling, cell proliferation and tumor growth. Here, using cell viability assays, we report that INPP4B overexpression does not affect the sensitivity of ER⁺ breast cancer cells to standard-of-care treatments including the anti-estrogen 4-hydroxytamoxifen (4-OHT) or the PI3Kα inhibitor alpelisib. Examination of four small molecule Wnt inhibitors revealed that ER⁺ breast cancer cells with INPP4B overexpression were more sensitive to the FDA-approved drug pyrvinium and a 4-OHT-pyrvinium combination treatment. Using 3D culture models, we demonstrated that pyrvinium selectively reduced the size of INPP4B-overexpressing ER⁺ breast cancer spheroids in the presence and absence of 4-OHT. These findings suggest that repurposing pyrvinium as a Wnt inhibitor may be an effective therapeutic strategy for human ER⁺ breast cancers with high INPP4B levels.

Pyrvinium Pamoate: Past, Present, and Future as an Anti-Cancer Drug

Pyrvinium, a lipophilic cation belonging to the cyanine dye family, has been used in the clinic as a safe and effective anthelminthic for over 70 years. Its structure, similar to some polyaminopyrimidines and mitochondrial-targeting peptoids, has been linked with mitochondrial localization and targeting. Over the past two decades, increasing evidence has emerged showing pyrvinium to be a strong anti-cancer molecule in various human cancers in vitro and in vivo. This efficacy against cancers has been attributed to diverse mechanisms of action, with the weight of evidence supporting the inhibition of mitochondrial function, the WNT pathway, and cancer stem cell renewal. Despite the overwhelming evidence demonstrating the efficacy of pyrvinium for the treatment of human cancers, pyrvinium has not yet been repurposed for the treatment of cancers. This review provides an in-depth analysis of the history of pyrvinium as a therapeutic, the rationale and data supporting its use as an anticancer agent, and the challenges associated with repurposing pyrvinium as an anti-cancer agent.

Pyrvinium doubles against WNT-driven cancer

The WNT-β-catenin signaling pathway has a major role in regulating cell proliferation and differentiation. Aberrant activation of the pathway contributes to various human cancer types. Because casein kinase CK1α-initiated phosphorylation of β-catenin is a key first step to restrain WNT signaling, effective restoration of CK1α activity represents an innovative strategy to combat WNT-driven cancer. A recent study in JBC reveals the anthelmintic pyrvinium directly binds to CK1α as an activator and also stabilizes CK1α protein, doubling against WNT-driven cancer activity.

Niclosamide and Pyrvinium Are Both Potential Therapeutics for Osteosarcoma, Inhibiting Wnt-Axin2-Snail Cascade

Simple Summary

Epithelial–mesenchymal transition (EMT) regulated by Wnt signaling is known as a key mechanism of cancer progression. Although evidence has suggested that the oncogenic Wnt signaling pathway and EMT program are important in the progression of osteosarcoma, there is no known therapeutic drug targeting EMT for osteosarcoma. We investigated whether Axin2, an important EMT target, could be a suitable molecular target and biomarker for osteosarcoma. Furthermore, we showed that both niclosamide and pyrvinium target Axin2, and effectively induce EMT reversion in osteosarcoma cell lines. Our findings suggest an effective biomarker and potential EMT therapeutics for osteosarcoma patients.

Abstract

Osteosarcoma, the most common primary bone malignancy, is typically related to growth spurts during adolescence. Prognosis is very poor for patients with metastatic or recurrent osteosarcoma, with survival rates of only 20–30%. Epithelial–mesenchymal transition (EMT) is a cellular mechanism that contributes to the invasion and metastasis of cancer cells, and Wnt signaling activates the EMT program by stabilizing Snail and β-catenin in tandem. Although the Wnt/Snail axis is known to play significant roles in the progression of osteosarcoma, and the anthelmintic agents, niclosamide and pyrvinium, have been studied as inhibitors of the Wnt pathway, their therapeutic effects and regulatory mechanisms in osteosarcoma remain unidentified. In this study, we show that both niclosamide and pyrvinium target Axin2, resulting in the suppression of EMT by the inhibition of the Wnt/Snail axis in osteosarcoma cells. Axin2 and Snail are abundant in patient samples and cell lines of osteosarcoma. The treatment of niclosamide and pyrvinium inhibits the migration of osteosarcoma cells at nanomolar concentrations. These results suggest that Axin2 and Snail are candidate therapeutic targets in osteosarcoma, and that anthelminthic agents, niclosamide and pyrvinium, may be effective for osteosarcoma patients.

Pyrvinium Treatment Confers Hepatic Metabolic Benefits via β-Catenin Downregulation and AMPK Activation

Genetic evidence has indicated that β-catenin plays a vital role in glucose and lipid metabolism. Here, we investigated whether pyrvinium, an anthelmintic agent previously reported as a down-regulator of cellular β-catenin levels, conferred any metabolic advantages in treatment of metabolic disorders. Glucose production and lipid accumulation were analyzed to assess metabolic response to pyrvinium in hepatocytes. The expression of key proteins and genes were assessed by immunoblotting and RT-PCR. The in vivo efficacy of pyrvinium against metabolic disorders was evaluated in the mice fed with a high fat diet (HFD). We found that pyrvinium inhibited glucose production and reduced lipogenesis by decreasing the expression of key genes in hepatocytes, which were partially elicited by the downregulation of β-catenin through AXIN stabilization. Interestingly, the AMPK pathway also played a role in the action of pyrvinium, dependent on AXIN stabilization but independent of β-catenin downregulation. In HFD-fed mice, pyrvinium treatment led to improvement in glucose tolerance, fatty liver disorder, and serum cholesterol levels along with a reduced body weight gain. Our results show that small molecule stabilization of AXIN using pyrvinium may lead to improved glucose and lipid metabolism, via β-catenin downregulation and AMPK activation.

Synergistic Effect of Pyrvinium Pamoate and Azoles Against Aspergillus fumigatus in vitro and in vivo

The effects of pyrvinium pamoate alone and in combination with azoles [itraconazole (ITC), posaconazole (POS), and voriconazole (VRC)] were evaluated against Aspergillus fumigatus both in vitro and in vivo. A total of 18 clinical strains of A. fumigatus were studied, including azole-resistant isolates harboring the combination of punctual mutation and a tandem repeat sequence in the Cyp51A gene (AFR1 with TR34/L98H and AFR2 with TR46/Y121F/T289A). The in vitro results revealed that pyrvinium individually exhibited minimal inhibitory concentration (MIC) of 2 μg/ml against AFR1 but was ineffective against other tested strains (MIC > 32 μg/ml). Nevertheless, the synergistic effects of pyrvinium with ITC, VRC, or POS were observed in 15 [83.3%, fractional inhibitory concentration index (FICI) 0.125-0.375], 11 (61.1%, FICI 0.258-0.281), and 16 (88.9%, FICI 0.039-0.281) strains, respectively, demonstrating the potential of pyrvinium in reversion of ITC and POS resistance of both AFR1 (FICI 0.275, 0.281) and AFR2 (FICI 0.125, 0.039). The effective MIC ranges in synergistic combinations were 0.25-8 μg/ml for pyrvinium, 0.125-4 μg/ml for ITC, and 0.125 μg/ml for both VRC and POS, demonstrating 4- to 32-fold reduction in MICs of azoles and up to 64-fold reduction in MICs of pyrvinium, respectively. There was no antagonism. The effect of pyrvinium-azole combinations in vivo was evaluated by survival assay and fungal burden determination in the Galleria mellonella model infected with AF293, AFR1, and AFR2. Pyrvinium alone significantly prolonged the survival of larvae infected with AF293 (P < 0.01) and AFR1 (P < 0.0001) and significantly decreased the tissue fungal burden of larvae infected with AFR1 (P < 0.0001). Pyrvinium combined with azoles significantly improved larvae survival (P < 0.0001) and decreased larvae tissue fungal burden in all three isolates (P < 0.0001). Notably, despite AFR2 infection was resistant to VRC or pyrvinium alone, pyrvinium combined with VRC significantly prolonged survival of both AFR1 and AFR2 infected larvae (P < 0.0001). In summary, the preliminary results indicated that the combination with pyrvinium and azoles had the potential to overcome azole resistance issues of A. fumigatus and could be a promising option for anti-Aspergillus treatment.

Identification of Pyrvinium, an Anthelmintic Drug, as a Novel Anti-Adipogenic Compound Based on the Gene Expression Microarray and Connectivity Map

Obesity is a serious health problem, while the current anti-obesity drugs are not very effective. The Connectivity Map (C-Map), an in-silico drug screening approach based on gene expression profiles, has recently been indicated as a promising strategy for drug repositioning. In this study, we performed mRNA expression profile analysis using microarray technology and identified 435 differentially expressed genes (DEG) during adipogenesis in both C3H10T1/2 and 3T3-L1 cells. Then, DEG signature was uploaded into C-Map, and using pattern-matching methods we discovered that pyrvinium, a classical anthelminthic, is a novel anti-adipogenic differentiation agent. Pyrvinium suppressed adipogenic differentiation in a dose-dependent manner, as evidenced by Oil Red O staining and the mRNA levels of adipogenic markers. Furthermore, we identified that the inhibitory effect of pyrvinium was resulted primarily from the early stage of adipogenesis. Molecular studies showed that pyrvinium downregulated the expression of key transcription factors C/EBPa and PPARγ. The mRNA levels of notch target genes Hes1 and Hey1 were obviously reduced after pyrvinium treatment. Taken together, this study identified many differentially expressed genes involved in adipogenesis and demonstrated for the first time that pyrvinium is a novel anti-adipogenic compound for obesity therapy. Meanwhile, we provided a new strategy to explore potential anti-obesity drugs.

Targeting Wnt Signaling through Small molecules in Governing Stem Cell Fate and Diseases

BACKGROUND

The conserved Wnt/β-catenin signaling pathway is responsible for multiple functions including regulation of stem cell pluripotency, cell migration, self-renewability and cell fate determination. This signaling pathway is of utmost importance, owing to its ability to fuel tissue repair and regeneration of stem cell activity in diverse organs. The human adult stem cells including hematopoietic cells, intestinal cells, mammary and mesenchymal cells rely on the manifold effects of Wnt pathway. The consequences of any dysfunction or manipulation in the Wnt genes or Wnt pathway components result in specific developmental defects and may even lead to cancer, as it is often implicated in stem cell control. It is absolutely essential to possess a comprehensive understanding of the inhibition and/ or stimulation of the Wnt signaling pathway which in turn is implicated in determining the fate of the stem cells.

RESULTS

In recent years, there has been considerable interest in the studies associated with the implementation of small molecule compounds in key areas of stem cell biology including regeneration differentiation, proliferation. In support of this statement, small molecules have unfolded as imperative tools to selectively activate and inhibit specific developmental signaling pathways involving the less complex mechanism of action. These compounds have been reported to modulate the core molecular mechanisms by which the stem cells regenerate and differentiate.

CONCLUSION

This review aims to provide an overview of the prevalent trends in the small molecules based regulation of stem cell fate via targeting the Wnt signaling pathway.

Targeting the eIF4E/β-catenin axis sensitizes cervical carcinoma squamous cells to chemotherapy

Chemotherapy has improved the clinical outcomes of cervical cancer patients. However, patients develop chemoresistance, whose underlying mechanisms are not well understood. In this study, we investigated the phosphorylation levels of eukaryotic translation initiation factor 4E (eIF4E) in cervical cancer cells subjected to chemotherapy. Results showed that chemotherapeutic drugs significantly increased eIF4E phosphorylation at S209 in HeLa and SiHa cells. Upregulation of phosphorylated eIF4E (p-eIF4E) levels has also been shown in cisplatin-resistant HeLa cells and has been observed to be a common response of cervical cancer patients undergoing chemotherapy. We further showed that chemotherapeutic drugs increase β-catenin activity and mRNA levels of Wnt/β-catenin target genes in cervical cancer cells but not in eIF4E-depleted cells, suggesting that chemotherapeutic drugs activate Wnt/β-catenin signaling in an eIF4E-dependent manner. Inhibiting eIF4E via siRNA knockdown or Wnt/β-catenin using the Wnt inhibitor pyrvinium effectively enhanced the anti-proliferative and pro-apoptotic effects of cisplatin in cervical cancer cells both in vitro and in vivo. Our findings demonstrate that eIF4E/β-catenin signaling plays a positive regulatory role in the resistance of cervical cancer cell to chemotherapy and thus highlight the therapeutic value of eIF4E or β-catenin inhibition in overcoming chemoresistance.

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/β-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.