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Nathan Goodyear

Growth Inhibition of Ovarian Tumor-Initiating Cells by Niclosamide | Molecular Cancer T... - 0 views

  • Ovarian cancer is the most lethal gynecologic malignancy and the fifth-most cause of overall cancer death of women in developed countries
  • An increasingly accepted cancer stem cell hypothesis regards tumors as caricatures of normal organs, possessing a hierarchy of cell types, at various stages of aberrant differentiation, descended from precursor tumor-initiating cells (TIC) cells that are highly resistant to conventional cytotoxics
  • Significant changes of gene expression in 2,928 genes were identified after niclosamide treatment for different time periods
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  • uncoupling of mitochondrial oxidative phosphorylation is believed to be its anti-helminthic mechanism of action
  • we hypothesized that niclosamides antagonistic effects on OTICs could, in part, be due to its disruption of metabolism
  • niclosamide represses metabolic enzymes responsible for bioenergetics, biosynthesis, and redox regulation specifically in OTICs, presumably leading to mitochondrial intrinsic apoptosis pathways, loss of tumor stemness, and growth inhibition
  • niclosamide treatment resulted in a more than 20% increase in reactive oxygen species (ROS) in cultured OTICs
  • niclosamide, which has proved to be safe and effective for the past 2 decades against numerous parasites, inhibited OTIC growth both in vitro and in vivo
  • Our results showed that genes participating in protein complexes of oxidative phosphorylation were downregulated
  • Niclosamide is believed to inhibit mitochondrial oxidative phosphorylation
  • Niclosamide was reported to inactivate NF-κB, causing mitochondrial damage and the generation of ROS, leading to apoptosis of leukemic stem cells
  • niclosamide were identified in a screen for mTOR-signaling inhibitors
  • mTOR was reported to maintain stemness properties of HSCs by inhibiting mitochondrial biogenesis and ROS levels (39), implying that mTOR inhibitors (such as niclosamide) may interfere with mitochondria and various metabolic pathways in TICs via disruption of antioxidant responses
  • We observed Wnt hyperactivity in OTICs, in agreement with previous hypotheses of Wnt inhibitor effectiveness as an ovarian cancer therapy
  • niclosamide has now been independently identified in screens for Wnt inhibitors
  • downregulation of the Wnt/β-catenin target oncogenes survivin and c-Myc
  • ovarian carcinogenesis, the cell-to-cell signaling pathway Notch (8), were also suppressed by niclosamide (data not shown). These results agree with another recent niclosamide study in leukemia (49), and it has been widely hypothesized that disruption of Notch signaling may represent a highly effective therapy for ovarian and other solid tumors, via its essentiality to maintaining TIC stemness
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    Niclosamide, common anti-parasitic medication, inhibits cellular metabolism and increases ROS; both of which provide powerful anti-proliferative, anti-cancer treatment mechanism in TICs. Powerful target therapy for cancer stem cells. Also shown to inhibit Wnt stimulated oncogenes survivin and c-Myc, disrupts Notch signaling, inactivates NF-kappaBeta, and inhibits mTOR-signaling.  This has been found in in vitro and in vivo studies.
Nathan Goodyear

Niclosamide, an old antihelminthic agent, demonstrates antitumor activity by blocking m... - 0 views

  • Accumulating evidence suggests that niclosamide targets multiple signaling pathways such as nuclear factor-kappaB (NF-kB), Wnt/β-catenin, and Notch, most of which are closely involved with cancer stem cell proliferation
  • The transcription factor NF-κB has been demonstrated to promote cancer growth, angiogenesis, escape from apoptosis, and tumorigenesis
  • NF-κB is sequestered in the cytosol of resting cells through binding the inhibitory subunit IκBα
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  • Niclosamide blocked TNFα-induced IκBα phosphorylation, translocation of p65, and the expression of NF-κB-regulated genes
  • Niclosamide also inhibited the DNA binding of NF-κB to the promoter of its target genes
  • niclosamide has two independent effects: NF-kB activation and ROS elevation
  • The Wnt signaling pathway plays fundamental roles in directing tissue patterning in embryonic development, in maintaining tissue homeostasis in differentiated tissue, and in tumorigenesis
  • niclosamide is a potent inhibitor of the Wnt/β-catenin pathway
  • The Notch signaling pathway plays important roles in a variety of cellular processes such as proliferation, differentiation, apoptosis, cell fate decisions, and maintenance of stem cells
  • niclosamide potently suppresses the luciferase activity of a CBF-1-dependent reporter gene in both a dose-dependent and a time-dependent manners in K562 leukemia cells
  • niclosamide treatment abrogated the epidermal growth factor (EGF)-stimulated dimerization and nuclear translocation and transcriptional activity of Stat3, and induced cell growth inhibition and apoptosis in several types of cancer cells (e.g. Du145, Hela, A549) that exhibit relatively higher levels of Stat3 constitutive activation
  • niclosamide can rapidly increase autophagosome formation
  • niclosamide induced autophagy and inhibited mammalian target of rapamycin complex 1 (mTORC1)
  • Niclosamide has low toxicity in mammals (oral median lethal dose in rats >5000 mg/kg
  • Niclosamide is active against cancer cells such as AML and colorectal cancer cells, not only as a monotherapy but also as part of combination therapy, in which it has been found to be synergistic with frontline chemotherapeutic agents (e.g., oxaliplatin, cytarabine, etoposide, and daunorubicin)
  • Because niclosamide targets multiple signaling pathways (e.g., NF-κB, Wnt/β-catenin, and Notch), most of which are closely involved with cancer stem cells, it holds promise in eradicating cancer stem cells
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    Review article: common anti-parasitic medication, niclosamide, provides anti-proliferative effect in cancer stem cells (CSC), via inhibition of NF-kappaBeta, Wnt/B-catenin, Notch, ROS, mTORC1, and STAT2 pathways.
Nathan Goodyear

Antineoplastic Mechanisms of Niclosamide in Acute Myelogenous Leukemia Stem C... - 0 views

  • Here, we report on niclosamide as an antileukemic agent with two independent antineoplastic mechanisms: NF-κB pathway inactivation and ROS generation
  • In this report, we validated the inhibitory action of niclosamide against tumor necrosis factor (TNF)–induced NF-κB activation in AML cells and identified its mechanism, together with generation of reactive oxygen species (ROS), as being responsible for induced apoptosis of AML cells
  • NF-κB plays a critical role in inflammation, antiapoptotic responses, and carcinogenesis
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  • pharmacologic inhibition of NF-κB was effective in killing AML cells
  • High NF-κB expression is found in primitive human AML blast cells
  • niclosamide inhibited the TNF-induced NF-κB reporter activity in a dose- and time-dependent manner
  • niclosamide inhibiting TNF-induced IKK phosphorylation (Fig. 2A), niclosamide may exert its inhibitory effect at the TAK1 step
  • Pretreatment with niclosamide completely blocked the time- and dose-dependent TNFα-induced alteration of the NF-κB–DNA complex
  • niclosamide inhibited constitutively active NF-κB binding to DNA in U266 cells
  • niclosamide completely abolished the TNFα-induced phosphorylation of IKKα/β and IκBα
  • Accordingly, the TNFα-induced degradation of IκBα was abrogated by niclosamide
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    Old anti-parasitic medication, niclosamide, found to have anti-leukemic acitivty through inactivation of NF-kappaB and increase in ROS production in in Vitro and in Vivo study.
Nathan Goodyear

Niclosamide Suppresses Cancer Cell Growth By Inducing Wnt Co-Receptor LRP6 De... - 0 views

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    Niclosamide, a common antilemintic/anti-parasitic medication, inhibits Wnt/Beta-catenin signaling involved in carcinogenesis and metastasis. the mechanism is through LRP6 degradation to provide antiproliferative and apoptosis activity.
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