Pyrvinium Pamoate: An Anti Worm Drug with Important Anti Cancer Potential

Summary:

Pyrvinium Pamoate (PP) (a quinoline-derived cyanine dye) is an relatively non toxic anthelmintic drug, FDA-approved, sold over the counter in countries like Sweden, Norway, Denmark used to treat pinworms in humans and animals.

During the recent years this compound has been shown to effectively inhibit various cancer cells types such as brain, colon/colorectal, breast, prostate, etc. and patented as a treatment of cancers such as adrenocortical, hepatocellular, hepatoblastoma, malignant melanoma, ovarian, Wilm’s tumor, Barrett’s esophageal, glioma, bladder, breast, gastric, head & neck, lung cell, mesothelioma, and cervical cancers due to its potential to inhibit Wnt activity in the cells of cancers (Wnt pathway is an important signaling pathway specifically relevant when targeting cancer stem cells) (Ref.).

My specific interest in  Pyrvinium was triggered by a very recent (2015) article published in the well known journal Nature. This article presents research performed by scientists in Japan who developed a novel high throughput drug screening system to identify compounds with strong anti-tumor effect, in this case focused on lymphoma. Following the screening of 2613 known pharmacologically active substance and off-patent drugs, including most of well know chemotheraphies, tehy found out one element that was standing out in terms of anti cancer effectiveness. That was Pyrvinium Pamoate. (Ref.)
In the Supplemental Table 3 of this article you will find a list with the top drugs identified. Following this finding, the researchers have also tested the effect of Pyrvinium on the DLB1 xenograft and they concluded the following: “A single administration was enough for tumor disappearance (Fig. 3D), demonstrating the high anti-tumor activity of PP”

PP is an effective element against cancer stem cells (CSC) due to reason explain below, in the Mechanisms section.

PP was shown and patented as an agent to promote wound healing and repair (Ref.)

Mechanisms:

• inhibited glutathione supply from stromal cells to lymphoma cells (Ref.)
• inhibits WNT signaling via activation of casein kinase 1α (CK-1α – a key kinase that phosphorylates β-catenin for degradation) (Ref.)
• inhibition of cancer stem cells (via the down-regulation of EMT) due to inhibition of WNT signaling (EMT has been shown to be a downstream target of WNT) (Ref.)
• non-competitive androgen receptor inhibitor (Ref.)
• inhibitor of NADH-fumarate reductase system, a metabolic system in mitochondria (Ref.) Indeed data suggest that, contrary to the classical Warburg view,tumor cells in nutritionally-compromised microenvironments are dependent on mitochondrial function for energy metabolism and survival. These findings suggest that mitochondria may represent an “Achilles heel” for the survival of slowly-proliferating tumor cells and suggest strategies for the development of therapy to target these cell populations. (Ref.)
  • anti-cancer drug targeting mitochondrial respiration (Ref.)
• can sensitize tumor cells to radiation therapy (Ref.)
• Pyrvinium targets autophagy addiction to promote cancer cell death (Ref.)

Source:

As capsule, commercially available as antiworm over the counter medicine in Sweeden, Norway, Danemark under the name Vanquin, for example:

• https://www.komplettapotek.no/product/860366/mor-og-barn/smaabarnsplager/vanquin-tabletter-50mg#
• https://www.kronansapotek.se/kronans/sv/Alla-produkter/Vanquin-Vanquin-ta-50-mg-50-mg-32-styck/p/174755

In Germany under brand name MOLEVAC:

• https://www.medizinfuchs.de/preisvergleich/molevac-8-st-infectopharm-arzn.u.consilium-gmbh-pzn-683476.html

As solution, Pyrcon brand in Germany, over the counter (maybe this one can be nebulized? – I have to check the content):

• https://www.medizinfuchs.de/preisvergleich/pyrcon-25-ml-infectopharm-arzn.u.consilium-gmbh-pzn-4023245.html

As it can be seen, it is a very low cost drug. It may be found in other countries as well.

In powder form, it is available at western chemical suppliers but expensive http://www.sigmaaldrich.com/catalog/search?term=3546-41-6&interface=CAS%20No.&N=0&mode=partialmax&lang=en&region=NL&focus=product Alternatively, it is available at Chinese suppliers at a cost of about 3o0USD for 10g of substance which should be enough for applications other than oral administrations.
When ordering from chemical suppliers we need to ask for the following CAS number 3546-41-6.

Safety and Warnings:

Tablets should be swallowed whole to avoid staining of teeth. This drug will color the stool a bright red which is not harmful to the patient. The compound is a strong red dye so it will color anything – so be aware of that but not afraid since is not harmful (Ref.).

Dose & Application:

Oral administration:

Typically, this drug is administrated orally. However, its bio-availability seems to be very low (Ref.). This to me means that even if it is able to kill most of the cancers, it may also not reach most of them at high enough dose!?

Yet, taken orally maybe very relevant to all forms of cancers that can easily be reached in that way, i.e. gastric, colon, colorectal, blader and possibly hepatocellular.

The typical dose suggested for human usage is 5mg/kg/day (which results in an intestinal drug concentration of ~100μM (Ref.) while 1 μM has been shown to induced strong cell death in lymphoma (Ref.)). That means 250mg/day for a 50kg person. The maximum dose suggested for daily administration is 350mg/day regardless of the weight. I have to further investigate how much we can go beyond this dose and still be safe (remember that for e.g. Mebendazole the daily suggested dose is 200mg but clinics administrated to humans >1000mg/day and found that to be safe – In addition I do not see why there would be a safety issue at higher doses since it is anyway not well absorbed).

The capsules are usually of 50mg and the 5mg/kg/day (i.e. 5 capsules for a 50kg person) is administrated all at once, one time only. As an anti worm medicine this may be repeated after 2 to 4 weeks (Ref.). As an anti cancer treatment however, I expect this would need to be administrated more often. I have no reference here and my guess is that we may need to take it every day during a week or every other day during two weeks and repeat after e.g. two weeks.

Other ways to administrate:

Topically: For those cancers accessible via topical application we may mix Pyrvinuim powder (crushed capsule? or bought as a powder) with DMSO since it seems to be soluble in DMSO (solubility is >10mg/ml – Ref). Topical administration may even deliver Pyrvinium in to the blood and as a result access other loccations.

IV or Injection: Ultimately, I should also be able to prepare it in an IV form given that it is soluble in DMSO and Ethanol. With that any location can be reached. However, in this case I would still need to clarify what are the safe blood concentration.

Synergies:

There are several publications indicating that the best anti cancer effect of Pyrvinium seems to take place during glucose starvation. (Ref1, Ref2).

Indeed, here is another study stating the same in a different way:”VCD blocked GRP78 expression only when glycolysis was impaired (due to hypoglycemia or the presence of the glycolysis inhibitor 2-deoxyglucose) … the possibility that other purported GRP78 inhibitors (arctigenin, biguanides, deoxyverrucosidin, efrapeptin, JBIR, piericidin, prunustatin, pyrvinium, rottlerin, valinomycin, versipelostatin) might act in a similar GRP78-independent fashion” (Ref.)

2-DG: “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.” http://www.nature.com/cddis/journal/v4/n5/full/cddis2013142a.html

Chemotherapy: “However, the combination of pyrvinium and Doxorubicin demonstrated significantly enhanced efficacy in vivo, supporting a mechanistic treatment concept based on tumor hypoglycemia and UPR.”  http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0003951

Other References:

Discovery of a drug targeting microenvironmental support for lymphoma cells by screening using patient-derived xenograft cells. http://www.ncbi.nlm.nih.gov/pubmed/26278963 http://www.nature.com/articles/srep13054

Cell lines have been used for drug discovery as useful models of cancers; however, they do not recapitulate cancers faithfully, especially in the points of rapid growth rate and microenvironment independency. Consequently, the majority of conventional anti-cancer drugs are less sensitive to slow growing cells and do not target microenvironmental support, although most primary cancer cells grow slower than cell lines and depend on microenvironmental support. Here, we developed a novel high throughput drug screening system using patient-derived xenograft (PDX) cells of lymphoma that maintained primary cancer cell phenotype more than cell lines. The library containing 2613 known pharmacologically active substance and off-patent drugs were screened by this system. We could find many compounds showing higher cytotoxicity than conventional anti-tumor drugs. Especially, pyruvinium pamoate showed the highest activity and its strong anti-tumor effect was confirmed also in vivo. We extensively investigated its mechanism of action and found that it inhibited glutathione supply from stromal cells to lymphoma cells, implying the importance of the stromal protection from oxidative stress for lymphoma cell survival and a new therapeutic strategy for lymphoma. Our system introduces a primary cancer cell phenotype into cell-based phenotype screening and sheds new light on anti-cancer drug development.

The structure of PP is shown in Fig. 3A. PP was originally approved as an anthelminthic. Recently, it attracted particular attention as an anti-tumor drug since it was revealed to have cytotoxicity against various cancer cell lines. We first confirmed the lymphoma cell-specific cytotoxicity of PP. In the co-culture of DLB1 cells with BLS4, 1 μM PP induced strong cell death, specifically of lymphoma cells (Fig. 3B). GI50 at 48 h of PP for DLB1 cells co-cultured with BLS4 was 0.137 μM, while even 1 μM PP did not significantly affect the viability of BLS4 and GI50 was not determined (Fig. 3C). Next, we examined the effect of PP on the DLB1 xenograft. PP is an anthelminthic for intestinal parasites and administered orally in humans. But its bioavailability is very poor and its systemic absorption hardly occurs in human15. In addition, after the intraperitoneal administration of PP at the maximum tolerated dose (5 mg/kg), the maximum serum level of PP was 99.3 nM at 15 minutes after the injection16, indicating that the blood concentration of PP could not reach to the level expected to be effective for lymphoma by intraperitoneal administration; therefore, we administered PP locally. PP 20 mg/kg was administered directly to the subcutaneous tumors of DLB1 cells and BLS4. A single administration was enough for tumor disappearance (Fig. 3D), demonstrating the high anti-tumor activity of PP in vivo. Furthermore, PP also induced strong growth suppression of the subcutaneous tumor of DLB2 cells, another lymphoma PDX cells, indicating the possible wide range effectiveness of PP for lymphoma cells

Pyrvinium Targets the Unfolded Protein Response to Hypoglycemia and Its Anti-Tumor Activity Is Enhanced by Combination Therapy http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2597738/

We identified pyrvinium pamoate, an old anthelminthic medicine, which preferentially inhibits anchorage-independent growth of cancer cells over anchorage-dependent growth (∼10 fold). It was also reported by others to have anti-tumor activity in vivo and selective toxicity against cancer cells under glucose starvation in vitro, but with unknown mechanism. Here, we provide evidence that pyrvinium suppresses the transcriptional activation of GRP78 and GRP94 induced by glucose deprivation or 2-deoxyglucose (2DG, a glycolysis inhibitor), but not by tunicamycin or A23187. Other UPR pathways induced by glucose starvation, e.g. XBP-1, ATF4, were also found suppressed by pyrvinium. Constitutive expression of GRP78 via transgene partially protected cells from pyrvinium induced cell death under glucose starvation, suggesting that suppression of the UPR is involved in pyrvinium mediated cytotoxicity under glucose starvation. Xenograft experiments showed rather marginal overall anti-tumor activity for pyrvinium as a monotherapy. However, the combination of pyrvinium and Doxorubicin demonstrated significantly enhanced efficacy in vivo, supporting a mechanistic treatment concept based on tumor hypoglycemia and UPR.

Pyrvinium Wound Treatment Methods and Devices http://www.google.com/patents/US20120318262

Pyrvinium targets autophagy addiction to promote cancer cell death http://www.nature.com/cddis/journal/v4/n5/full/cddis2013142a.html

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.

Pyrvinium Targets the Unfolded Protein Response to Hypoglycemia and Its Anti-Tumor Activity Is Enhanced by Combination Therapy http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0003951

We identified pyrvinium pamoate, an old anthelminthic medicine, which preferentially inhibits anchorage-independent growth of cancer cells over anchorage-dependent growth (∼10 fold). It was also reported by others to have anti-tumor activity in vivo and selective toxicity against cancer cells under glucose starvation in vitro, but with unknown mechanism. Here, we provide evidence that pyrvinium suppresses the transcriptional activation of GRP78 and GRP94 induced by glucose deprivation or 2-deoxyglucose (2DG, a glycolysis inhibitor), but not by tunicamycin or A23187. Other UPR pathways induced by glucose starvation, e.g. XBP-1, ATF4, were also found suppressed by pyrvinium. Constitutive expression of GRP78 via transgene partially protected cells from pyrvinium induced cell death under glucose starvation, suggesting that suppression of the UPR is involved in pyrvinium mediated cytotoxicity under glucose starvation. Xenograft experiments showed rather marginal overall anti-tumor activity for pyrvinium as a monotherapy. However, the combination of pyrvinium and Doxorubicin demonstrated significantly enhanced efficacy in vivo, supporting a mechanistic treatment concept based on tumor hypoglycemia and UPR.

Pyrvinium For The Treatment of Cancer http://www.google.com/patents/US20090099062

The present invention concerns a pyrvinium compound or an analog thereof for the treatment of cancers. This compound inhibits Wnt activity in the cells of cancers such as adrenocortical, hepatocellular, hepatoblastoma, malignant melanoma, ovarian, Wilm’s tumor, Barrett’s esophageal, glioma, bladder, breast, gastric, head & neck, lung cell, mesothelioma, and cervical cancers. The present invention also provides a method for assaying for compounds that alter Wnt pathway activity. Also provided are methods for treating Wnt-related non-cancer disease states.

Repositioning of Verrucosidin, a purported inhibitor of chaperone protein GRP78, as an inhibitor of mitochondrial electron transport chain complex I http://www.ncbi.nlm.nih.gov/pubmed/23755268

Verrucosidin (VCD) belongs to a group of fungal metabolites that were identified in screening programs to detect molecules that preferentially killcancer cells under glucose-deprived conditions. Its mode of action was proposed to involve inhibition of increased GRP78 (glucose regulated protein 78) expression during hypoglycemia. Because GRP78 plays an important role in tumorigenesis, inhibitors such as VCD might harbor cancertherapeutic potential. We therefore sought to characterize VCD’s anticancer activity in vitro. Triple-negative breast cancer cell lines MDA-MB-231 and MDA-MB-468 were treated with VCD under different conditions known to trigger increased expression of GRP78, and a variety of cellular processes were analyzed. We show that VCD was highly cytotoxic only under hypoglycemic conditions, but not in the presence of normal glucose levels, and VCD blocked GRP78 expression only when glycolysis was impaired (due to hypoglycemia or the presence of the glycolysis inhibitor 2-deoxyglucose), but not when GRP78 was induced by other means (hypoxia, thapsigargin, tunicamycin). However, VCD’s strictly hypoglycemia-specific toxicity was not due to the inhibition of GRP78. Rather, VCD blocked mitochondrial energy production via inhibition of complex I of the electron transport chain. As a result, cellular ATP levels were quickly depleted under hypoglycemic conditions, and common cellular functions, including general protein synthesis, deteriorated and resulted in cell death. Altogether, our study identifies mitochondria as the primary target of VCD. The possibility that other purported GRP78 inhibitors (arctigenin, biguanides, deoxyverrucosidin, efrapeptin, JBIR, piericidin, prunustatin, pyrvinium, rottlerin, valinomycin, versipelostatin) might act in a similar GRP78-independent fashion will be discussed.

Histone acetylation-mediated regulation of the Hippo pathway http://www.ncbi.nlm.nih.gov/pubmed/23671600

WNT pathway inhibitor pyrvinium pamoate inhibits the self-renewal and metastasis of breast cancer stem cells http://www.ncbi.nlm.nih.gov/pubmed/26781188

Acquisition of chemoresistance and metastatic phenotype are the major causes of breast cancer treatment failure and cancer-related mortality. Recently, a plethora of experimental and clinical studies points toward a central role of cancer stem cells (CSCs) in the chemoresistance and metastasis. In the present study, we demonstrated that pyrvinium pamoate (PP), an anthelmintic drug, inhibited proliferation of different subtypes of breast cancer cells (luminal: MCF-7, claudin-low: MDA-MB‑231, basal-like: MDA-MB‑468 and Her-2 enriched: SkBr-3) as a novel WNT pathway inhibitor. Additionally, PP was also shown to inhibit self-renewal of breast cancer stem cells (BCSCs) and decrease both CD44+CD24-/low and ALDH-positive BCSCs content in a panel of breast cancer cell lines. Besides, the metastatic potential and expression of EMT markers (such as N-cadherin, vimentin, Snail) were also found suppressed by PP. By using a xenograft model, we next tested the efficacy of PP on tumorigenicity of MDA-MB‑231, one of the most aggressive breast cancer cell lines, and we observed PP significantly delayed tumor growth in vivo. Moreover, in-depth analysis revealed that PP caused inhibition of WNT pathway activity and stemness regulator expression including NANOG, SOX2 and OCT4, which were inherently upregulated in the BCSCs as compared with the bulk of cells within the tumor. Collectively, our findings provide direct evidence for PP serving as a promising high-yield agent targeting BCSCs and cancer heterogeneity. Therefore, strategies combining PP with standard chemotherapy drugs which fail to eliminate the BCSCs hold promise to overcome BCSCs associated treatment resistance and achieve a better therapeutic outcome

Pyrvinium selectively induces apoptosis of lymphoma cells through impairing mitochondrial functions and JAK2/STAT5. http://www.ncbi.nlm.nih.gov/pubmed/26707639

Targeting mitochondrial respiration has emerged as an attractive therapeutic strategy in blood cancer due to their unique metabolic dependencies. In this study, we show that pyrvinium, a FDA-approved anthelmintic drug, selectively targets lymphoma T-cells though inhibition of mitochondrialfunctions and JAK2/STAT5. Pyrvinium induces apoptosis of malignant T-cell line Jurkat and primary T-cells from lymphoma patients while sparing T-cells from healthy donors. Increased level of active caspase-3 and decreased levels of Bcl-2 and Mcl-1 were also observed in Jurkat and lymphoma T-cells but not normal T-cells treated with pyrvinium. In addition, pyrvinium impairs mitochondrial functions by inhibit mitochondrial respiration, suppressing mitochondrial respiratory complex I activity, increasing ROS and decreasing ATP levels. However, the effects of pyrvinium were abolished in mitochondrial respiration-deficient Jurkat ρ(0) cells, confirming that pyrvinium acts on lymphoma T-cells via targeting mitochondrial respiration. We further show that lymphoma T-cells derived from patients depend more on mitochondrial respiration than normal T-cells, and this explains the selective toxicity of pyrvinium in lymphoma versus normal T-cells. Finally, we demonstrate that pyrvinium also suppresses JAK2/STAT5 signaling pathway in Jurkat cells. Our study suggests that pyrvinium is a useful addition to T-cell lymphoma treatment, and emphasizes the potential therapeutic value of the differences in the mitochondrial characteristics between malignant and normal T-cells in blood cancer.

Pyrvinium selectively targets blast phase-chronic myeloid leukemia through inhibition of mitochondrial respiration. http://www.ncbi.nlm.nih.gov/pubmed/26378050

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 inhibitstumor 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.

Pyrvinium Targets CD133 in Human Glioblastoma Brain Tumor-Initiating Cells. http://www.ncbi.nlm.nih.gov/pubmed/26152745

Clonal evolution of cancer may be regulated by determinants of stemness, specifically self-renewal, and current therapies have not considered how genetic perturbations or properties of stemness affect such functional processes. Glioblastoma-initiating cells (GICs), identified by expression of the cell surface marker CD133, are shown to be chemoradioresistant. In the current study, we sought to elucidate the functional role of CD133 in self-renewal and identify compounds that can specifically target this CD133(+) treatment-refractory population.

Using gain/loss-of-function studies for CD133 we assessed the in vitro self-renewal and in vivo tumor formation capabilities of patient-derived glioblastoma cells. We generated a CD133 signature combined with an in silico screen to find compounds that target GICs. Self-renewal and proliferation assays on CD133-sorted samples were performed to identify the preferential action of hit compounds. In vivo efficacy of the lead compound pyrvinium was assessed in intracranial GIC xenografts and survival studies. Lastly, microarray analysis was performed on pyrvinium-treated GICs to discover core signaling events involved.

We discovered pyrvinium, a small-molecule inhibitor of GIC self-renewal in vitro and in vivo, in part through inhibition of Wnt/β-catenin signaling and other essential stem cell regulatory pathways. We provide a therapeutically tractable strategy to target self-renewing, chemoradioresistant, and functionally important CD133(+) stem cells that drive glioblastoma relapse and mortality.

Our study provides an integrated approach for the eradication of clonal populations responsible for cancer progression, and may apply to other aggressive and heterogeneous cancers. Clin Cancer Res; 21(23); 5324-37. ©2015 AACR.

Wnt blockers inhibit the proliferation of lung cancer stem cells. http://www.ncbi.nlm.nih.gov/pubmed/25960639

Previous study has confirmed that the occurrence of Wnt pathway activation is associated with risk of non-small-cell lung cancerrecurrence. However, whether the pharmacologic blocking of the Wnt signaling pathway could provide therapeutic possibility remains unknown. The aim of the present study was to evaluate the therapeutic functions of the Wnt signaling pathway inhibitor pyrvinium pamoate (PP) on lung cancer stem cells (LCSCs) in vitro.

Colony formation and sphere culture were performed to enrich LCSCs from three lung cancer cell lines: PC9, SPC-A1, and A549. After confirming stemness by immunofluorescence, PP was employed for cell viability assay by comparison with three other kinds of Wnt signaling inhibitor: salinomycin, ICG-001, and silibinin. The effect of PP on LCSCs was further verified by colony formation assay and gene expression analysis.

LCSCs were successfully generated by sphere culture from SPC-A1 and PC9 cells, but not A549 cells. Immunofluorescence assay showed that LCSCs could express pluripotent stem cell markers, including NANOG, Oct4, KLF5, and SOX2, and Wnt signaling pathway molecules β-catenin and MYC. Half-maximal inhibitory concentrations of PP on SPC-A1, PC9, and A549 were 10 nM, 0.44 nM, and 0.21 nM, respectively, which are much lower than those of salinomycin, ICG-001, and silibinin. Moreover, significantly decreased colony formation and downregulation of pluripotent stem cell signaling pathway were observed in lung cancer cells after treatment with PP.

Wnt signaling inhibitor PP can inhibit proliferation of LCSCs, and the Wnt signaling pathway could be considered a promising therapeutic or interventional target in lung adenocarcinoma.

Antibiotics that target mitochondria effectively eradicate cancer stem cells, across multiple tumor types: treating cancer like an infectious disease. http://www.ncbi.nlm.nih.gov/pubmed/25625193

Here, we propose a new strategy for the treatment of early cancerous lesions and advanced metastatic disease, via the selective targeting of cancerstem cells (CSCs), a.k.a., tumor-initiating cells (TICs). We searched for a global phenotypic characteristic that was highly conserved among cancerstem cells, across multiple tumor types, to provide a mutation-independent approach to cancer therapy. This would allow us to target cancer stem cells, effectively treating cancer as a single disease of “stemness”, independently of the tumor tissue type. Using this approach, we identified a conserved phenotypic weak point – a strict dependence on mitochondrial biogenesis for the clonal expansion and survival of cancer stem cells. Interestingly, several classes of FDA-approved antibiotics inhibit mitochondrial biogenesis as a known “side-effect”, which could be harnessed instead as a “therapeutic effect”. Based on this analysis, we now show that 4-to-5 different classes of FDA-approved drugs can be used to eradicate cancerstem cells, in 12 different cancer cell lines, across 8 different tumor types (breast, DCIS, ovarian, prostate, lung, pancreatic, melanoma, and glioblastoma (brain)). These five classes of mitochondrially-targeted antibiotics include: the erythromycins, the tetracyclines, the glycylcyclines, an anti-parasitic drug, and chloramphenicol. Functional data are presented for one antibiotic in each drug class: azithromycin, doxycycline, tigecycline,pyrvinium pamoate, as well as chloramphenicol, as proof-of-concept. Importantly, many of these drugs are non-toxic for normal cells, likely reducing the side effects of anti-cancer therapy. Thus, we now propose to treat cancer like an infectious disease, by repurposing FDA-approved antibiotics for anti-cancer therapy, across multiple tumor types. These drug classes should also be considered for prevention studies, specifically focused on the prevention of tumor recurrence and distant metastasis. Finally, recent clinical trials with doxycycline and azithromycin (intended to target cancer-associated infections, but not cancer cells) have already shown positive therapeutic effects in cancer patients, although their ability to eradicatecancer stem cells was not yet appreciated.

The impact of pyrvinium pamoate on colon cancer cell viability. http://www.ncbi.nlm.nih.gov/pubmed/25060218

The in vitro and in vivo effects of pyrvinium pamoate (PP), a newly identified WNT signaling inhibitor, were evaluated against colon cancercell lines and primary colon cancer samples.

Antiproliferative activity of PP and its effects on protein and RNA levels of WNT targets were evaluated on adenomatous polyposis coli (APC (mut)) and β-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.

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.

PP displays promising anticancer activity against a broad panel of human colon cancer cell lines, as well as primary colon cancersamples. 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. http://www.ncbi.nlm.nih.gov/pubmed/24354286

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.

The antihelmintic drug pyrvinium pamoate targets aggressive breast cancer. http://www.ncbi.nlm.nih.gov/pubmed/24013655

WNT signaling plays a key role in the self-renewal of tumor initiation cells (TICs). In this study, we used pyrvinium pamoate (PP), an FDA-approved antihelmintic drug that inhibits WNT signaling, to test whether pharmacologic inhibition of WNT signaling can specifically target TICs of aggressive breast cancer cells. SUM-149, an inflammatory breast cancer cell line, and SUM-159, a metaplastic basal-type breast cancer cell line, were used in these studies. We found that PP inhibited primary and secondary mammosphere formation of cancer cells at nanomolar concentrations, at least 10 times less than the dose needed to have a toxic effect on cancer cells. A comparable mammosphere formation IC50 dose to that observed in cancercell lines was obtained using malignant pleural effusion samples from patients with IBC. A decrease in activity of the TIC surrogate aldehyde dehydrogenase was observed in PP-treated cells, and inhibition of WNT signaling by PP was associated with down-regulation of a panel of markers associated with epithelial-mesenchymal transition. In vivo, intratumoral injection was associated with tumor necrosis, and intraperitoneal injection into mice with tumor xenografts caused significant tumor growth delay and a trend toward decreased lung metastasis. In in vitro mammosphere-based and monolayer-based clonogenic assays, we found that PP radiosensitized cells in monolayer culture but not mammosphere culture. These findings suggest WNT signaling inhibition may be a feasible strategy for targeting aggressive breast cancer. Investigation and modification of the bioavailability and toxicity profile of systemic PP are warranted.

Targeting the Wnt pathway in synovial sarcoma models. http://www.ncbi.nlm.nih.gov/pubmed/23921231

Synovial sarcoma is an aggressive soft-tissue malignancy of children and young adults, with no effective systemic therapies. Its specific oncogene, SYT-SSX (SS18-SSX), drives sarcoma initiation and development. The exact mechanism of SYT-SSX oncogenic function remains unknown. In an SYT-SSX2 transgenic model, we show that a constitutive Wnt/β-catenin signal is aberrantly activated by SYT-SSX2, and inhibition of Wnt signaling through the genetic loss of β-catenin blocks synovial sarcoma tumor formation. In a combination of cell-based and synovial sarcoma tumor xenograft models, we show that inhibition of the Wnt cascade through coreceptor blockade and the use of small-molecule CK1α activators arrests synovial sarcoma tumor growth. We find that upregulation of the Wnt/β-catenin cascade by SYT-SSX2 correlates with its nuclear reprogramming function. These studies reveal the central role of Wnt/β-catenin signaling in SYT-SSX2-induced sarcoma genesis, and open new venues for the development of effective synovial sarcoma curative agents.

Synovial sarcoma is an aggressive soft-tissue cancer that afflicts children and young adults, and for which there is no effective treatment. The current studies provide critical insight into our understanding of the pathogenesis of SYT–SSX-dependent synovial sarcoma and pave the way for the development of effective therapeutic agents for the treatment of the disease in humans.

Synergistic effects of combined Wnt/KRAS inhibition in colorectal cancer cells. http://www.ncbi.nlm.nih.gov/pubmed/23227266

Activation of Wnt signalling due to inability to degrade β-catenin is found in >85% of colorectal cancers. Approximately half of colon cancers express a constitutively active KRAS protein. A significant fraction of patients show both abnormalities. We previously reported that simultaneous down-regulation of both β-catenin and KRAS was necessary to induce significant cell death and tumor growth inhibition of colorectal cancer cells. Although attractive, an RNAi-based therapeutic approach is still far from being employed in the clinical setting. Therefore, we sought to recapitulate our previous findings by the use of small-molecule inhibitors of β-catenin and KRAS. We show here that the β-catenin inhibitors PKF115-584 andpyrvinium pamoate block β-catenin-dependent transcriptional activity and synergize with the KRAS inhibitor S-trans, trans-farnesylthiosalicylic acid (FTS, salirasib) in colon cancer cells driven by Wnt and KRAS oncogenic signals, but not in cells carrying BRAF mutations. The combined use of these compounds was superior to the use of any drug alone in inducing cell growth arrest, cell death, MYC and survivin down-modulation, and inhibition of anchorage-independent growth. Expression analysis of selected cancer-relevant genes revealed down-regulation of CD44 as a common response to the combined treatments. These data provide a proof of principle for a combination therapeutic strategy in colorectal cancer.

Reprofiling a classical anthelmintic, pyrvinium pamoate, as an anti-cancer drug targeting mitochondrial respiration http://www.ncbi.nlm.nih.gov/pubmed/23061049

Pyrvinium pamoate (PP) is an FDA-approved classical anthelmintic, but is now attracting particular attention as an anti-cancer drug after recent findings of its potent cytotoxicity against various cancer cell lines only during glucose starvation, as well as its anti-tumor activity against hypovascularpancreatic cancer cells transplanted in mice. The molecular mechanisms by which PP promotes such preferential toxicity against cancer cells are currently under extensive investigation. PP suppressed the NADH-fumarate reductase system that mediates a reverse reaction of the mitochondrial electron-transport chain complex II in anaerobic organisms such as parasitic helminthes or mammalian cells under tumor microenvironment-mimicking hypoglycemic/hypoxic conditions, thereby inhibiting efficient ATP production. PP also inhibited the unfolded protein response induced by glucose starvation, thereby inhibiting the proliferation of pancreatic cancer cells. Even under normoglycemic/normoxic conditions, PP suppressed the mitochondrial electron-transport chain complex I and thereby STAT3, inhibiting the proliferation of myeloma/erythroleukemia cells. Here, we review accumulating knowledge on its working mechanisms and evaluate PP as a novel anti-cancer drug that targets mitochondrial respiration.

Repositioning approved drugs for the treatment of problematic cancers using a screening approach http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0171052#pone.0171052.ref043

Advances in treatment strategies together with an earlier diagnosis have considerably increased the average survival of cancer patients over the last four decades. Nevertheless, despite the growing number of new antineoplastic agents introduced each year, there is still no adequate therapy for problematic malignancies such as pancreatic, lung and stomach cancers. Consequently, it is important to ensure that existing drugs used to treat other types of cancers, and potentially other diseases, are not overlooked when searching for new chemotherapy regimens for these problematic cancer types. We describe a screening approach that identifies chemotherapeutics for the treatment of lung and pancreatic cancers, based on drugs already approved for other applications. Initially, the 1280 chemically and pharmacologically diverse compounds from the Prestwick Chemical Library® (PCL) were screened against A549 (lung cancer) and PANC-1 (pancreatic carcinoma) cells using the PrestoBlue fluorescent-based cell viability assay. More than 100 compounds from the PCL were identified as hits in one or both cell lines (80 of them, being drugs used to treat diseases other than cancer). Selected PCL hits were further evaluated in a dose-response manner. Promising candidates for repositioning emanating from this study include antiparasitics, cardiac glycosides, as well as the anticancer drugs vorinostat and topotecan.

Disclaimer:

This site is not designed to and does not provide medical advice, professional diagnosis, opinion, treatment or services to you or to any other individual. Through this site and linkages to other sites, I provide general information for educational purposes only. The information provided in this site, or through linkages to other sites, is not a substitute for medical or professional care, and you should not use the information in place of a visit, call consultation or the advice of your physician or other healthcare provider. I am not liable or responsible for any advice, course of treatment, diagnosis or any other information, services or product you obtain through this site. This is just my own personal opinion regarding what we have learned on this road.

Related Articles