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Nathan Goodyear

Induction of metastasis, cancer stem cell phenotype, and oncogenic metabolism in cancer... - 0 views

www.ncbi.nlm.nih.gov/...PMC5282724

EMT TME metastasis cancer stem cells cancer MMP2 Notch MMP-9 MMP-2 radioresistance Hedgehog CSC MMP9 Snail HIF-1alpha tumor microenvironment epithelial to mesenchymal transition TGF-beta radiation

shared by Nathan Goodyear on 09 Feb 21 - No Cached
  • More than half of cancer patients are treated with IR at some point during their treatment
  • fractionation schedule is the delivery of 1.8–2.0 Gy per day, five days per week
  • Nuclear DNA is the primary target of IR; it causes DNA damage (genotoxic stress) by direct DNA ionization
  • ...121 more annotations...
  • IR also indirectly induces DNA damage by stimulating reactive oxygen species (ROS) production
  • IR is known to induce EMT in vitro
  • p53 is activated in response to IR-induced DNA damage
  • IR paradoxically also promotes tumour recurrence and metastasis
  • DNA double-strand breaks (DSBs)
  • cancer cells undergoing EMT acquire invasive and metastatic properties
  • changes in the tumour microenvironment (TME)
  • IR seems to induce EMT and CSC phenotypes by regulating cellular metabolism
  • EMT, stemness, and oncogenic metabolism are known to be associated with resistance to radiotherapy and chemotherapy
  • Hanahan and Weinberg proposed ten hallmarks of cancer that alter cell physiology to enhance malignant growth: 1) sustained proliferation, 2) evasion of growth suppression, 3) cell death resistance, 4) replicative immortality, 5) evasion of immune destruction, 6) tumour-promoting inflammation, 7) activation of invasion and metastasis, 8) induction of angiogenesis, 9) genome instability, and 10) alteration of metabolism
  • EMT is a developmental process that plays critical roles in embryogenesis, wound healing, and organ fibrosis
  • IR is known to induce stemness and metabolic alterations in cancer cells
  • transforming growth factor-β [TGF-β], epidermal growth factor [EGF]) and their associated signalling proteins (Wnt, Notch, Hedgehog, nuclear-factor kappa B [NF-κB], extracellular signal-regulated kinase [ERK], and phosphatidylinositol 3-kinase [PI3K]/Akt
  • activate EMT-inducing transcription factors, including Snail/Slug, ZEB1/δEF1, ZEB2/SIP1, Twist1/2, and E12/E47
  • Loss of E-cadherin is considered a hallmark of EMT
  • IR has been shown to induce EMT to enhance the motility and invasiveness of several cancer cells, including those of breast, lung, and liver cancer, and glioma cells
  • IR may increase metastasis in both the primary tumour site and in normal tissues under some circumstance
  • sublethal doses of IR have been shown to enhance the migratory and invasive behaviours of glioma cells
  • ROS are known to play an important role in IR-induced EMT
  • High levels of ROS trigger cell death by causing irreversible damage to cellular components such as proteins, nucleic acids, and lipids, whereas low levels of ROS have been shown to promote tumour progression—including tumour growth, invasion, and metastasis
  • hypoxia-inducible factor-1 (HIF-1) is involved in IR-induced EMT
  • Treatment with the N-acetylcysteine (NAC), a general ROS scavenger, prevents IR-induced EMT, adhesive affinity, and invasion of breast cancer cells
    • Nathan Goodyear
      Nathan Goodyear on 09 Feb 21
       
      NAC for all patients receiving radiation therapy
  • Snail has been shown to play a crucial role in IR-induced EMT, migration, and invasion
  • IR activates the p38 MAPK pathway, which contributes to the induction of Snail expression to promote EMT and invasion
  • NF-κB signalling that promotes cell migration
  • ROS promote EMT to allow cancer cells to avoid hostile environments
  • HIF-1 is a heterodimer composed of an oxygen-sensitive α subunit and a constitutively expressed β subunit.
  • Under normoxia, HIF-1α is rapidly degraded, whereas hypoxia induces stabilisation and accumulation of HIF-1α
  • levels of HIF-1α mRNA are enhanced by activation of the PI3K/Akt/mammalian target of rapamycin (mTOR)
  • IR is known to increase stabilisation and nuclear accumulation of HIF-1α, since hypoxia is a major condition for HIF-1 activation
  • IR induces vascular damage that causes hypoxia
  • ROS is implicated in IR-induced HIF-1 activation
  • IR causes the reoxygenation of hypoxic cancer cells to increase ROS production, which leads to the stabilisation and nuclear accumulation of HIF-1
  • IR increases glucose availability under reoxygenated conditions that promote HIF-1α translation by activating the Akt/mTOR pathway
  • The stabilised HIF-1α then translocates to the nucleus, dimerizes with HIF-1β, and increases gene expression— including the expression of essential EMT regulators such as Snail—to induce EMT, migration, and invasion
  • TGF-β signalling has been shown to play a crucial role in IR-induced EMT
  • AP-1 transcription factor is involved in IR-induced TGF-β1 expression
  • Wnt/β-catenin signalling is also implicated in IR-induced EMT
  • Notch signalling is known to be involved in IR-induced EMT
  • IR also increases Notch-1 expression [99]. Notch-1 is known to induce EMT by upregulating Snail
  • PAI-1 signalling is also implicated in IR-induced Akt activation that increases Snail levels to induce EMT
  • EGFR activation is known to be associated with IR-induced EMT, cell migration, and invasion by activating two downstream pathways: PI3K/Akt and Raf/MEK/ERK
  • ROS and RNS are also implicated in IR-induced EGFR activation
  • IR has also been shown to activate Hedgehog (Hh) signalling to induce EMT
  • IR has been shown to induce Akt activation through several signalling pathways (EGFR, C-X-C chemokine receptor type 4 [CXCR4]/C-X-C motif chemokine 12 [CXCL12], plasminogen activator inhibitor 1 [PAI-1]) and upstream regulators (Bmi1, PTEN) that promote EMT and invasion
  • CSCs possess a capacity for self-renewal, and they can persistently proliferate to initiate tumours upon serial transplantation, thus enabling them to maintain the whole tumour
  • Conventional cancer treatments kill most cancer cells, but CSCs survive due to their resistance to therapy, eventually leading to tumour relapse and metastasis
  • identification of CSCs, three types of markers are utilised: cell surface molecules, transcription factors, and signalling pathway molecules
  • CSCs express distinct and specific surface markers; commonly used ones are CD24, CD34, CD38, CD44, CD90, CD133, and ALDH
  • Transcription factors, including Oct4, Sox2, Nanog, c-Myc, and Klf4,
  • signalling pathways, including those of TGF-β, Wnt, Hedgehog, Notch, platelet-derived growth factor receptor (PDGFR), and JAK/STAT
  • microRNAs (miRNAs), including let-7, miR-22, miR-34a, miR-128, the miR-200 family, and miR-451
  • Non-CSCs can be reprogrammed to become CSCs by epigenetic and genetic changes
  • EMT-inducing transcription factors, such as Snail, ZEB1, and Twist1, are known to confer CSC properties
  • Signalling pathways involved in EMT, including those of TGF-β, Wnt, and Notch, have been shown to play important roles in inducing the CSC phenotype
  • TGF-β1 not only increases EMT markers (Slug, Twist1, β-catenin, N-cadherin), but also upregulates CSC markers (Oct4, Sox2, Nanog, Klf4) in breast and lung cancer cells
  • some CSC subpopulations arise independently of EMT
  • IR has been shown to induce the CSC phenotype in many cancers, including breast, lung, and prostate cancers, as well as melanoma
  • Genotoxic stress due to IR or chemotherapy promotes a CSC-like phenotype by increasing ROS production
  • IR has been shown to induce reprogramming of differentiated cancer cells into CSCs
  • In prostate cancer patients, radiotherapy increases the CD44+ cell population that exhibit CSC properties
  • IR also induces the re-expression of stem cell regulators, such as Sox2, Oct4, Nanog, and Klf4, to promote stemness in cancer cells
  • EMT-inducing transcription factors and signalling pathways, including Snail, STAT3, Notch signalling, the PI3K/Akt pathway, and the MAPK cascade, have been shown to play important roles in IR-induced CSC properties
  • STAT3 directly binds to the Snail promoter and increases Snail transcription, which induces the EMT and CSC phenotypes, in cisplatin-selected resistant cells
  • Other oncogenic metabolic pathways, including glutamine metabolism, the pentose phosphate pathway (PPP), and synthesis of fatty acids and cholesterol, are also enhanced in many cancers
  • metabolic reprogramming
  • HIF-1α, p53, and c-Myc, are known to contribute to oncogenic metabolism
  • metabolic reprogramming
  • tumour cells exhibit high mitochondrial metabolism as well as aerobic glycolysis
  • occurring within the same tumour
  • CSCs can be highly glycolytic-dependent or oxidative phosphorylation (OXPHOS)-dependen
  • mitochondrial function is crucial for maintaining CSC functionality
  • cancer cells depend on mitochondrial metabolism and increase mitochondrial production of ROS that cause pseudo-hypoxia
  • HIF-1 then enhances glycolysis
  • CAFs have defective mitochondria that lead to the cells exhibiting the Warburg effect; the cells take up glucose, and then secrete lactate to 'feed' adjacent cancer cells
  • lactate transporter, monocarboxylate transporter (MCT)
  • nutrient microenvironment
  • Epithelial cancer cells express MCT1, while CAFs express MCT4. MCT4-positive, hypoxic CAFs secrete lactate by aerobic glycolysis, and MCT1-expressing epithelial cancer cells then uptake and use that lactate as a substrate for the tricarboxylic acid (TCA) cycle
  • MCT4-positive cancer cells depend on glycolysis and then efflux lactate, while MCT1-positive cells uptake lactate and rely on OXPHOS
  • metabolic heterogeneity induces a lactate shuttle between hypoxic/glycolytic cells and oxidative/aerobic tumour cells
  • bulk tumour cells exhibit a glycolytic phenotype, with increased conversion of glucose to lactate (and enhanced lactate efflux through MCT4), CSC subsets depend on oxidative phosphorylation; most of the glucose entering the cells is converted to pyruvate to fuel the TCA cycle and the electron transport chain (ETC), thereby increasing mitochondrial ROS production
  • the major fraction of glucose is directed into the pentose phosphate pathway, to produce redox power through the generation of NADPH and ROS scavengers
  • HIF-1α, p53, and c-Myc, are known to contribute to oncogenic metabolism
  • regulatory molecules involved in EMT and CSCs, including Snail, Dlx-2, HIF-1, STAT3, TGF-β, Wnt, and Akt, are implicated in the metabolic reprogramming of cancer cells
  • HIF-1 induces the expression of glycolytic enzymes, including the glucose transporter GLUT, hexokinase, lactate dehydrogenase (LDH), and MCT, resulting in the glycolytic switch
  • HIF-1 represses the expression of pyruvate dehydrogenase kinase (PDK), which inhibits pyruvate dehydrogenase (PDH), thereby inhibiting mitochondrial activity
  • STAT3 has been implicated in EMT-induced metabolic changes as well
  • TGF-β and Wnt play important roles in the metabolic alteration of cancer cells
  • Akt is also implicated in the glycolytic switch and in promoting cancer cell invasiveness
  • EMT, invasion, metastasis, and stemness
  • pyruvate kinase M2 (PKM2), LDH, and pyruvate carboxylase (PC), are implicated in the induction of the EMT and CSC phenotypes
  • decreased activity of PKM2 is known to promote an overall shift in metabolism to aerobic glycolysis
  • LDH catalyses the bidirectional conversion of lactate to pyruvate
  • High levels of LDHA are positively correlated with the expression of EMT and CSC markers
  • IR has been shown to induce metabolic changes in cancer cells
  • IR enhances glycolysis by upregulating GAPDH (a glycolysis enzyme), and it increases lactate production by activating LDHA, which converts pyruvate to lactate
  • IR enhances glycolysis by upregulating GAPDH (a glycolysis enzyme), and it increases lactate production by activating LDHA, which converts pyruvate to lactate
  • IR also elevates MCT1 expression that exports lactate into the extracellular environment, leading to acidification of the tumour microenvironment
  • IR increases intracellular glucose, glucose 6-phosphate, fructose, and products of pyruvate (lactate and alanine), suggesting a role for IR in the upregulation of cytosolic aerobic glycolysis
  • Lactate can activate latent TGF-
  • lactate stimulates cell migration and enhances secretion of hyaluronan from CAF that promote tumour metastasis
  • promote tumour survival, growth, invasion, and metastasis; enhance the stiffness of the ECM; contribute to angiogenesis; and induce inflammation by releasing several growth factors and cytokines (TGF-β, VEGF, hepatocyte growth factor [HGF], PDGF, and stromal cell-derived factor 1 [SDF1]), as well as MMP
  • tumours recruit the host tissue’s blood vessel network to perform four mechanisms: angiogenesis (formation of new vessels), vasculogenesis (de novo formation of blood vessels from endothelial precursor cells), co-option, and modification of existing vessels within tissues.
  • immunosuppressive cells such as tumour-associated macrophages (TAM), MDSCs, and regulatory T cells, and the immunosuppressive cytokines, TGF-β and interleukin-10 (IL-10)
  • immunosuppressive cells such as tumour-associated macrophages (TAM), MDSCs, and regulatory T cells, and the immunosuppressive cytokines, TGF-β and interleukin-10 (IL-10)
  • intrinsic immunogenicity or induce tolerance
  • cancer immunoediting’
  • three phases: 1) elimination, 2) equilibrium, and 3) escape.
  • The third phase, tumour escape, is mediated by antigen loss, immunosuppressive cells (TAM, MDSCs, and regulatory T cells), and immunosuppressive cytokines (TGF-β and IL-10).
  • IR can elicit various changes in the TME, such as CAF activity-mediated ECM remodelling and fibrosis, cycling hypoxia, and an inflammatory response
  • IR activates CAFs to promote the release of growth factors and ECM modulators, including TGF-β and MMP
  • TGF-β directly influences tumour cells and CAFs, promotes tumour immune escape, and activates HIF-1 signalling
    • Nathan Goodyear
      Nathan Goodyear on 09 Feb 21
       
      And now the receipts
  • MMPs degrade ECM that facilitates angiogenesis, tumour cell invasion, and metastasis
    • Nathan Goodyear
      Nathan Goodyear on 09 Feb 21
       
      Receipts and mechanisms
  • IR also promotes MMP-2/9 activation in cancer cells to promote EMT, invasion, and metastasis
  • IR-induced Snail increases MMP-2 expression to promote EMT
  • Radiotherapy has the paradoxical side-effect of increasing tumour aggressiveness
  • IR promotes ROS production in cancer cells, which may induce the activation of oncogenes and the inactivation of tumour suppressors, which further promote oncogenic metabolism
  • Metabolic alterations
  • oncogenic metabolism
  • elicit various changes in the TME
  • Although IR activates an antitumour immune response, this signalling is frequently suppressed by tumour escape mechanisms
  • Nathan Goodyear on 09 Feb 21
     
    Important review article.
Nathan Goodyear

Inflammatory cause of metabolic syndrome via brain stress and NF-κB - 0 views

www.ncbi.nlm.nih.gov/...PMC3314172

metabolic syndrome TLR cytokines hypothalamus brain neurology metabolic syndrome NF-kappaB DIO diet induced obesity over nutrition nutrition inflammation

shared by Nathan Goodyear on 09 Jul 13 - No Cached
  • Mechanistic studies further showed that such metabolic inflammation is related to the induction of various intracellular stresses such as mitochondrial oxidative stress, endoplasmic reticulum (ER) stress, and autophagy defect under prolonged nutritional excess
  • intracellular stress-inflammation process for metabolic syndrome has been established in the central nervous system (CNS) and particularly in the hypothalamus
  • the CNS and the comprised hypothalamus are known to govern various metabolic activities of the body including appetite control, energy expenditure, carbohydrate and lipid metabolism, and blood pressure homeostasis
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  • Reactive oxygen species (ROS) refer to a class of radical or non-radical oxygen-containing molecules that have high oxidative reactivity with lipids, proteins, and nucleic acids
  • a large measure of intracellular ROS comes from the leakage of mitochondrial electron transport chain (ETC)
  • Another major source of intracellular ROS is the intentional generation of superoxides by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase
  • there are other ROS-producing enzymes such as cyclooxygenases, lipoxygenases, xanthine oxidase, and cytochrome p450 enzymes, which are involved with specific metabolic processes
  • To counteract the toxic effects of molecular oxidation by ROS, cells are equipped with a battery of antioxidant enzymes such as superoxide dismutases, catalase, peroxiredoxins, sulfiredoxin, and aldehyde dehydrogenases
  • intracellular oxidative stress has been indicated to contribute to metabolic syndrome and related diseases, including T2D [72; 73], CVDs [74-76], neurodegenerative diseases [69; 77-80], and cancers
  • intracellular oxidative stress is highly associated with the development of neurodegenerative diseases [69] and brain aging
  • dietary obesity was found to induce NADPH oxidase-associated oxidative stress in rat brain
  • mitochondrial dysfunction in hypothalamic proopiomelanocortin (POMC) neurons causes central glucose sensing impairment
  • Endoplasmic reticulum (ER) is the cellular organelle responsible for protein synthesis, maturation, and trafficking to secretory pathways
  • unfolded protein response (UPR) machinery
  • ER stress has been associated to obesity, insulin resistance, T2D, CVDs, cancers, and neurodegenerative diseases
  • brain ER stress underlies neurodegenerative diseases
  • under environmental stress such as nutrient deprivation or hypoxia, autophagy is strongly induced to breakdown macromolecules into reusable amino acids and fatty acids for survival
  • intact autophagy function is required for the hypothalamus to properly control metabolic and energy homeostasis, while hypothalamic autophagy defect leads to the development of metabolic syndrome such as obesity and insulin resistance
  • prolonged oxidative stress or ER stress has been shown to impair autophagy function in disease milieu of cancer or aging
  • TLRs are an important class of membrane-bound pattern recognition receptors in classical innate immune defense
  • Most hypothalamic cell types including neurons and glia cells express TLRs
  • overnutrition constitutes an environmental stimulus that can activate TLR pathways to mediate the development of metabolic syndrome related disorders such as obesity, insulin resistance, T2D, and atherosclerotic CVDs
  • Isoforms TLR1, 2, 4, and 6 may be particularly pertinent to pathogenic signaling induced by lipid overnutrition
  • hypothalamic TLR4 and downstream inflammatory signaling are activated in response to central lipid excess via direct intra-brain lipid administration or HFD-feeding
  • overnutrition-induced metabolic derangements such as central leptin resistance, systemic insulin resistance, and weight gain
  • these evidences based on brain TLR signaling further support the notion that CNS is the primary site for overnutrition to cause the development of metabolic syndrome.
  • circulating cytokines can limitedly travel to the hypothalamus through the leaky blood-brain barrier around the mediobasal hypothalamus to activate hypothalamic cytokine receptors
  • significant evidences have been recently documented demonstrating the role of cytokine receptor pathways in the development of metabolic syndrome components
  • entral administration of TNF-α at low doses faithfully replicated the effects of central metabolic inflammation in enhancing eating, decreasing energy expenditure [158;159], and causing obesity-related hypertension
  • Resistin, an adipocyte-derived proinflammatory cytokine, has been found to promote hepatic insulin resistance through its central actions
  • both TLR pathways and cytokine receptor pathways are involved in central inflammatory mechanism of metabolic syndrome and related diseases.
  • In quiescent state, NF-κB resides in the cytoplasm in an inactive form due to inhibitory binding by IκBα protein
  • IKKβ activation via receptor-mediated pathway, leading to IκBα phosphorylation and degradation and subsequent release of NF-κB activity
  • Research in the past decade has found that activation of IKKβ/NF-κB proinflammatory pathway in metabolic tissues is a prominent feature of various metabolic disorders related to overnutrition
  • it happens in metabolic tissues, it is mainly associated with overnutrition-induced metabolic derangements, and most importantly, it is relatively low-grade and chronic
  • this paradigm of IKKβ/NF-κB-mediated metabolic inflammation has been identified in the CNS – particularly the comprised hypothalamus, which primarily accounts for to the development of overnutrition-induced metabolic syndrome and related disorders such as obesity, insulin resistance, T2D, and obesity-related hypertension
  • evidences have pointed to intracellular oxidative stress and mitochondrial dysfunction as upstream events that mediate hypothalamic NF-κB activation in a receptor-independent manner under overnutrition
  • In the context of metabolic syndrome, oxidative stress-related NF-κB activation in metabolic tissues or vascular systems has been implicated in a broad range of metabolic syndrome-related diseases, such as diabetes, atherosclerosis, cardiac infarct, stroke, cancer, and aging
  • intracellular oxidative stress seems to be a likely pathogenic link that bridges overnutrition with NF-κB activation leading to central metabolic dysregulation
  • overnutrition is an environmental inducer for intracellular oxidative stress regardless of tissues involved
  • excessive nutrients, when transported into cells, directly increase mitochondrial oxidative workload, which causes increased production of ROS by mitochondrial ETC
  • oxidative stress has been shown to activate NF-κB pathway in neurons or glial cells in several types of metabolic syndrome-related neural diseases, such as stroke [185], neurodegenerative diseases [186-188], and brain aging
  • central nutrient excess (e.g., glucose or lipids) has been shown to activate NF-κB in the hypothalamus [34-37] to account for overnutrition-induced central metabolic dysregulations
  • overnutrition can present the cell with a metabolic overload that exceeds the physiological adaptive range of UPR, resulting in the development of ER stress and systemic metabolic disorders
  • chronic ER stress in peripheral metabolic tissues such as adipocytes, liver, muscle, and pancreatic cells is a salient feature of overnutrition-related diseases
  • recent literature supports a model that brain ER stress and NF-κB activation reciprocally promote each other in the development of central metabolic dysregulations
  • when intracellular stresses remain unresolved, prolonged autophagy upregulation progresses into autophagy defect
  • autophagy defect can induce NF-κB-mediated inflammation in association with the development of cancer or inflammatory diseases (e.g., Crohn's disease)
  • The connection between autophagy defect and proinflammatory activation of NF-κB pathway can also be inferred in metabolic syndrome, since both autophagy defect [126-133;200] and NF-κB activation [20-33] are implicated in the development of overnutrition-related metabolic diseases
  • Both TLR pathway and cytokine receptor pathways are closely related to IKKβ/NF-κB signaling in the central pathogenesis of metabolic syndrome
  • Overnutrition, especially in the form of HFD feeding, was shown to activate TLR4 signaling and downstream IKKβ/NF-κB pathway
  • TLR4 activation leads to MyD88-dependent NF-κB activation in early phase and MyD88-indepdnent MAPK/JNK pathway in late phase
  • these studies point to NF-κB as an immediate signaling effector for TLR4 activation in central inflammatory response
  • TLR4 activation has been shown to induce intracellular ER stress to indirectly cause metabolic inflammation in the hypothalamus
  • central TLR4-NF-κB pathway may represent one of the early receptor-mediated events in overnutrition-induced central inflammation.
  • cytokines and their receptors are both upstream activating components and downstream transcriptional targets of NF-κB activation
  • central administration of TNF-α at low dose can mimic the effect of obesity-related inflammatory milieu to activate IKKβ/NF-κB proinflammatory pathways, furthering the development of overeating, energy expenditure decrease, and weight gain
  • the physiological effects of IKKβ/NF-κB activation seem to be cell type-dependent, i.e., IKKβ/NF-κB activation in hypothalamic agouti-related protein (AGRP) neurons primarily leads to the development of energy imbalance and obesity [34]; while in hypothalamic POMC neurons, it primarily results in the development of hypertension and glucose intolerance
  • the hypothalamus, is the central regulator of energy and body weight balance [
  • Nathan Goodyear on 09 Jul 13
     
    Great article chronicles the biochemistry of "over nutrition" and inflammation through NF-kappaB activation and its impact on the brain.
Nathan Goodyear

Mitochondrial Fission Induces Glycolytic Reprogramming in Cancer-Associated Myofibrobla... - 0 views

www.ncbi.nlm.nih.gov/...PMC3478457

warburg effect Cancer cancer associated fibroblasts CAFs reverse warburg effect lactate aerobic glycolysis mitochondria oxidative stress ROS H2O2

shared by Nathan Goodyear on 11 Nov 14 - No Cached
  • L-lactate functions as an onco-metabolite, stimulating mitochondrial biogenesis and OXPHOS in adjacent cancer cells, directly providing energy for tumor growth
  • Oxidative stress in stromal fibroblasts then induces their metabolic conversion into cancer-associated fibroblasts. Such oxidative stress drives the onset of autophagy, mitophagy, and aerobic glycolysis in fibroblasts, resulting in the local production of high-energy mitochondrial fuels (such as L-lactate, ketone bodies, and glutamine). These recycled nutrients are then transferred to cancer cells, where they are efficiently burned via oxidative mitochondrial metabolism (OXPHOS)
  • stromal L-lactate serves as a high-energy mitochondrial “fuel” for cancer cells. We have termed this new model of cancer metabolism “Two-Compartment Tumor Metabolism”, where two opposing metabolic compartments co-exist, side-by-side, with stromal glycolysis fueling OXPHOS in cancer cells
  • ...10 more annotations...
  • Two-Compartment Tumor Metabolism
  • Reverse Warburg Effect”, is that catabolic fibroblasts should promote tumor growth, without any increases in angiogenesis
  • when cancer cells use L-lactate as a mitochondrial fuel source, this metabolic phenotype is a predictor of lethal cancer metabolism
  • tumor microenvironment is intimately involved in tumor development and progression
  • mitochondrial dysregulation is likely the “root cause” of several human disease(s), and especially epithelial cancers
  • Both in vitro and in vivo studies have now provided convincing evidence that “activated” stromal fibroblasts, a.k.a., myofibroblasts, may play a critical role in initiating tumor recurrence, via paracrine interactions with adjacent tumor epithelial cells
  • A new hypothesis is that cancer is not a cell autonomous disease, but rather a disease of the tumor microenvironment
  • cancer cells behave as metabolic parasites, by inducing oxidative stress in adjacent normal fibroblasts
  • recent experimental evidence indicates that cancer-associated fibroblasts have a catabolic phenotype, and undergo autophagy and mitophagy, resulting in the onset of glycolytic metabolism, driving L-lactate production, and its release into the tumor microenvironment
  • oncogenic mutations in cancer cells lead to ROS production and the “secretion” of hydrogen peroxide species
  • Nathan Goodyear on 11 Nov 14
     
    A good discussion of what is proposed the Reverse Warburg effect.  A process by which the local environment dictates tumor progression.  The cancer cells release ROS primarily in the form of H2O2 and this leads to Cancer Associated Fibroblasts (CAFs) in the stroma.  The altered stromal environment increases ROS further and promotes ocogenic metabolites through the classic Warburg effect.  This high lactate production from the CAFs then is used by the cancer cells via classic oxidative phosphorylation.  Complex, beautiful and still an the understanding is a work in progress.   This study/article points to the importance of oxidative stress in some cancer development through CAFs.
Nathan Goodyear

Cancer cells metabolically "fertilize" the tumor microenvironment with hydrogen peroxid... - 0 views

www.ncbi.nlm.nih.gov/...PMC3180189

cancer reverse warburg effect warburg effect NF-kapppB HIF-1alpha Cav-1 H2O2

shared by Nathan Goodyear on 12 Nov 14 - No Cached
  • reducing oxidative stress with powerful antioxidants, is an important strategy for cancer prevention, as it would suppress one of the key early initiating steps where DNA damage and tumor-stroma metabolic-coupling begins. This would prevent cancer cells from acting as metabolic “parasites
  • Oxidative stress in cancer-associated fibroblasts triggers autophagy and mitophagy, resulting in compartmentalized cellular catabolism, loss of mitochondrial function, and the onset of aerobic glycolysis, in the tumor stroma. As such, cancer-associated fibroblasts produce high-energy nutrients (such as lactate and ketones) that fuel mitochondrial biogenesis and oxidative metabolism in cancer cells. We have termed this new energy-transfer mechanism the “reverse Warburg effect.
  • Then, oxidative stress, in cancer-associated fibroblasts, triggers the activation of two main transcription factors, NFκB and HIF-1α, leading to the onset of inflammation, autophagy, mitophagy and aerobic glycolysis in the tumor microenvironment
  • ...38 more annotations...
  • oxidative stress and ROS, produced in cancer-associated fibroblasts, has a “bystander effect” on adjacent cancer cells, leading to DNA damage, genomic instability and aneuploidy, which appears to be driving tumor-stroma co-evolution
  • tumor cells produce and secrete hydrogen peroxide, thereby “fertilizing” the tumor microenvironment and driving the “reverse Warburg effect.”
  • This type of stromal metabolism then produces high-energy nutrients (lactate, ketones and glutamine), as well as recycled chemical building blocks (nucleotides, amino acids, fatty acids), to literally “feed” cancer cells
  • loss of stromal caveolin (Cav-1) is sufficient to drive mitochondrial dysfunction with increased glucose uptake in fibroblasts, mimicking the glycolytic phenotype of cancer-associated fibroblasts.
  • oxidative stress initiated in tumor cells is transferred to cancer-associated fibroblasts.
  • Then, cancer-associated fibroblasts show quantitative reductions in mitochondrial activity and compensatory increases in glucose uptake, as well as high ROS production
  • These findings may explain the prognostic value of a loss of stromal Cav-1 as a marker of a “lethal” tumor microenvironment
  • aerobic glycolysis takes place in cancer-associated fibroblasts, rather than in tumor cells, as previously suspected.
  • our results may also explain the “field effect” in cancer biology,5 as hydrogen peroxide secreted by cancer cells, and the propagation of ROS production, from cancer cells to fibroblasts, would create an increasing “mutagenic field” of ROS production, due to the resulting DNA damage
  • Interruption of this process, by addition of catalase (an enzyme that detoxifies hydrogen peroxide) to the tissue culture media, blocks ROS activity in cancer cells and leads to apoptotic cell death in cancer cells
  • In this new paradigm, cancer cells induce oxidative stress in neighboring cancer-associated fibroblasts
  • cancer-associated fibroblasts have the largest increases in glucose uptake
  • cancer cells secrete hydrogen peroxide, which induces ROS production in cancer-associated fibroblasts
  • Then, oxidative stress in cancer-associated fibroblast leads to decreases in functional mitochondrial activity, and a corresponding increase in glucose uptake, to fuel aerobic glycolysis
  • cancer cells show significant increases in mitochondrial activity, and decreases in glucose uptake
  • fibroblasts and cancer cells in co-culture become metabolically coupled, resulting in the development of a “symbiotic” or “parasitic” relationship.
  • cancer-associated fibroblasts undergo aerobic glycolysis (producing lactate), while cancer cells use oxidative mitochondrial metabolism.
  • We have previously shown that oxidative stress in cancer-associated fibroblasts drives a loss of stromal Cav-1, due to its destruction via autophagy/lysosomal degradation
  • a loss of stromal Cav-1 is sufficient to induce further oxidative stress, DNA damage and autophagy, essentially mimicking pseudo-hypoxia and driving mitochondrial dysfunction
  • loss of stromal Cav-1 is a powerful biomarker for identifying breast cancer patients with early tumor recurrence, lymph-node metastasis, drug-resistance and poor clinical outcome
  • this type of metabolism (aerobic glycolysis and autophagy in the tumor stroma) is characteristic of a lethal tumor micro-environment, as it fuels anabolic growth in cancer cells, via the production of high-energy nutrients (such as lactate, ketones and glutamine) and other chemical building blocks
  • the upstream tumor-initiating event appears to be the secretion of hydrogen peroxide
  • one such enzymatically-active protein anti-oxidant that may be of therapeutic use is catalase, as it detoxifies hydrogen peroxide to water
  • numerous studies show that “catalase therapy” in pre-clinical animal models is indeed sufficient to almost completely block tumor recurrence and metastasis
  • by eliminating oxidative stress in cancer cells and the tumor microenvironment,55 we may be able to effectively cut off the tumor's fuel supply, by blocking stromal autophagy and aerobic glycolysis
  • breast cancer patients show systemic evidence of increased oxidative stress and a decreased anti-oxidant defense, which increases with aging and tumor progression.68–70 Chemotherapy and radiation therapy then promote further oxidative stress.69 Unfortunately, “sub-lethal” doses of oxidative stress during cancer therapy may contribute to tumor recurrence and metastasis, via the activation of myofibroblasts.
  • a loss of stromal Cav-1 is associated with the increased expression of gene profiles associated with normal aging, oxidative stress, DNA damage, HIF1/hypoxia, NFκB/inflammation, glycolysis and mitochondrial dysfunction
  • cancer-associated fibroblasts show the largest increases in glucose uptake, while cancer cells show corresponding decreases in glucose uptake, under identical co-culture conditions
  • Thus, increased PET glucose avidity may actually be a surrogate marker for a loss of stromal Cav-1 in human tumors, allowing the rapid detection of a lethal tumor microenvironment.
  • it appears that astrocytes are actually the cell type responsible for the glucose avidity.
  • In the brain, astrocytes are glycolytic and undergo aerobic glycolysis. Thus, astrocytes take up and metabolically process glucose to lactate.7
  • Then, lactate is secreted via a mono-carboxylate transporter, namely MCT4. As a consequence, neurons use lactate as their preferred energy substrate
  • both astrocytes and cancer-associated fibroblasts express MCT4 (which extrudes lactate) and MCT4 is upregulated by oxidative stress in stromal fibroblasts.34
  • In accordance with the idea that cancer-associated fibroblasts take up the bulk of glucose, PET glucose avidity is also now routinely used to measure the extent of fibrosis in a number of human diseases, including interstitial pulmonary fibrosis, postsurgical scars, keloids, arthritis and a variety of collagen-vascular diseases.
  • PET glucose avidity and elevated serum inflammatory markers both correlate with poor prognosis in breast cancers.
  • PET signal over-estimates the actual anatomical size of the tumor, consistent with the idea that PET glucose avidity is really measuring fibrosis and inflammation in the tumor microenvironment.
  • human breast and lung cancer patients can be positively identified by examining their exhaled breath for the presence of hydrogen peroxide.
  • tumor cell production of hydrogen peroxide drives NFκB-activation in adjacent normal cells in culture6 and during metastasis,103 directly implicating the use of antioxidants, NFκB-inhibitors and anti-inflammatory agents, in the treatment of aggressive human cancers.
  • Nathan Goodyear on 12 Nov 14
     
    Good description of the communication between cancer cells and fibroblasts.  This theory is termed the "reverse Warburg effect".
Nathan Goodyear

The anti-malarial drug artesunate causes cell cycle arrest and apoptosis of triple-nega... - 0 views

www.ncbi.nlm.nih.gov/...30660598

breast cancer cancer artesunate

shared by Nathan Goodyear on 01 Jul 19 - No Cached
  • Nathan Goodyear on 01 Jul 19
     
    ART inhibited breast cancer cell proliferation via a reactive oxygen species (ROS)-dependent G2/M arrest and ROS-independent G1 arrest. ART-treated MDA-MB-468 and SK-BR-3 cells also experienced apoptotic cell death, which was both ROS- and iron-dependent. ART-induced oxidative stress caused the loss of mitochondrial outer membrane integrity and damage to the cellular DNA of MDA-MB-468 and SK-BR-3 cells. Only abstract available...I will post full article once available.
Nathan Goodyear

Vitamin C inhibits granulocyte macrophage-colony-stimulating factor-induced signaling p... - 0 views

bloodjournal.hematologylibrary.org/...3205.full

ROS inflammation GM-CSF vitamin C vitamin C vitamins

shared by Nathan Goodyear on 10 Dec 12 - No Cached
  • Nathan Goodyear on 10 Dec 12
     
    vitamin C found to decrease inflammatory signaling.  In this study, they found a decrease in GM-CSF induction of  ROS due to vitamin C.  This was an in vitro study, but another flag in the claim that vitamin C reduces inflammation and ROS.
Nathan Goodyear

Severe oxidative damage in multiple sclerosis lesions coincides with enhanced antioxida... - 0 views

www.sciencedirect.com/...S0891584908005455

blood-brain barrier MS multiple sclerosis ROS reactive oxygen species antioxidants antioxidant SOD superoxide disumutase catalase

shared by Nathan Goodyear on 19 Mar 14 - No Cached
  • Nathan Goodyear on 19 Mar 14
     
    This article proposes that increased antioxidant enzymatic activity is an adaption to the increased ROS found in MS.  This increased ROS disrupts the blood-brain barrier.
Nathan Goodyear

Low mercury concentrations cause oxidative stress and endothelial dysfunction in conduc... - 0 views

ajpheart.physiology.org/...H1033.long

Hg mercury hypertension NO ROS oxidative stress glutathione GHS cardiovascular disease heart

shared by Nathan Goodyear on 16 Sep 14 - No Cached
  • Nathan Goodyear on 16 Sep 14
     
    Hg induces vascular ROS through depletion of glutathione.  This study found that low dose, chronic Hg exposure induced ROS that resulted in vascular dysfunction i.e. hypertension.
Nathan Goodyear

Multiple Myeloma Tumor Cells are Selectively Killed by Pharmacologically-dosed Ascorbic... - 0 views

www.ebiomedicine.com/...fulltext

multiple myeloma vitamin C IV vitamin C smoldering myeloma cancer

shared by Nathan Goodyear on 25 Sep 17 - No Cached
  • Recent reports indicate that a certain ROS concentration is required for high-dose vitamin C to induce cytotoxicity in cancer cells.
  • The generation of ascorbyl- and H2O2 radicals by PAA increases ROS stress in cancer cells
  • In this study, we report that PAA is efficacious in killing MM cells in vitro and in vivo models, which generated levels of 20–40 mM ascorbate and 500 nM ascorbyl radicals after intraperitoneal administration of 4 g ascorbate per kilogram of body weight (Chen et al., 2008Chen et al., 2008), in xenograft MM mice
  • ...33 more annotations...
  • These data suggest that PAA may show a therapeutic advantage to blood cancers vs solid tumors because of the communication between tumor cells and blood plasma
  • These results strongly suggest that the mechanism of PAA killing of MM cells is indeed iron-dependent
  • These results suggest that PAA administration in SMM may be able to prevent progression to symtomatic MM
  • A recent study by Yun and colleagues demonstrated that vitamin C selectively kills KRAS and BRAF mutant colorectal cancer cells by targeting GAPDH, but spares normal cells
  • RAS family genes show the most frequent mutations in MM. KRAS, NRAS and BRAF are mutated in 22%, 20% and 7% of MM samples
  • the disease stage rather than the mutation of RAS and/or BRAF is the major predictive factor for PAA sensitivity in MM treatment
  • Other molecular mechanisms including ATP depletion and ATM-AMPK signaling have been reported to explain PAA-induced cell death
  • our pilot study also suggested that PAA could overcome drug resistance to bortezomib in MM cells
  • Our findings complement reported studies and further address the mechanism of action using clinical samples in which we observed that PAA killed tumor cells with high iron content, suggesting that iron might be the initiator of PAA cytotoxicity
  • combination of PAA with standard therapeutic drugs, such as melphalan, may significantly reduce the dose of melphalan needed
  • Combined treatment of reduced dose melphalan with PAA achieved a significantly longer progression-free survival than the same dose of melphalan alone.
  • These data also suggest that the bone marrow suppression induced by high-dose melphalan can be ameliorated by the combination of PAA with lower dose of melphalan because of the lack of toxicity of PAA on normal cells with low iron content.
  • if creatinine clearance is <30 mL/min, high dose ascorbic acid should be not administrated.
  • In MM preclinical and clinical studies, ascorbate was used as an adjunct drug and showed controversial results (Harvey et al., 2009, Perrone et al., 2009, Held et al., 2013, Sharma et al., 2012, Nakano et al., 2011, Takahashi, 2010, Sharma et al., 2009, Qazilbash et al., 2008). However, none of these tests used pharmacological doses of ascorbate and intravenous administration
  • Multiple myeloma (MM) is a plasma cell neoplasm.
  • Cameron and Pauling reported that high doses of vitamin C increased survival of patients with cancer
  • pharmacologically dosed ascorbic acid (PAA) 50–100 g (Chen et al., 2008, Padayatty et al., 2004, Hoffer et al., 2008, Padayatty et al., 2006, Welsh et al., 2013), administered intravenously, has potent anti-cancer activity and its role as anti-cancer therapy is being studied at the University of Iowa and in other centers
  • In the presence of catalytic metal ions like iron, PAA administered intravenously exerts pro-oxidant effects leading to the formation of highly reactive oxygen species (ROS), resulting in cell death
  • the labile iron pool (LIP) is significantly elevated in MM cells
  • The survival of CD138+ cells in vitro was significantly decreased following PAA treatment in all 9 MM
  • In contrast, no significant change of cell viability was observed in CD138− BM cells from the same patients
  • The same effect of PAA was also observed in the SMM patients
  • no response to PAA was detected in CD138+ cells from the 2 MGUS patients
  • the combination of melphalan plus PAA showed greater tumor burden reduction than each drug alone, suggesting a synergistic activity between these two drugs
  • Both catalase and NAC protect cells from oxidative damage
  • cells pretreated with NAC and catalase became resistant to PAA even at high doses
  • adding deferoxamine (DFO), an iron chelator, to OCI-MY5 cells before PAA treatment was also sufficient to prevent PAA-induced cellular death
  • iron is essential for PAA to achieve its anti-cancer activity
  • PAA induced early necrosis (Fig. 3Fig. 3A, 60 min) followed by late apoptosis
  • results further indicated that PAA induced mitochondria-mediated apoptosis
  • PAA by reacting with LIP and generating ROS induces mitochondria-mediated apoptosis in which AIF1 cleavage is important for cell death.
  • ROS and H2O2 are well known factors mediating PAA-induced cancer cell death
  • PAA was sensitive to all 9 MMs and 2 SMMs
  • Nathan Goodyear on 25 Sep 17
     
    animal study finds high-dose, pharmacologic vitamin C found to kill multiple myeloma cells via pro-oxidant effect found in similar studies in dealing with different cancers.
Nathan Goodyear

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

mct.aacrjournals.org/...1703.long

Niclosamide Tumor-initiation cells TIC ovarian cancer cancer CSC cancer stem cells

shared by Nathan Goodyear on 16 Apr 18 - No Cached
  • 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
  • ...14 more annotations...
  • 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
  • Nathan Goodyear on 16 Apr 18
     
    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

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

cancerres.aacrjournals.org/...2516

Niclosamide cancer leukemia NF-kappaB ROS TNF tumor necrosis factor

shared by Nathan Goodyear on 21 Mar 18 - No Cached
  • 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
  • ...8 more annotations...
  • 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
  • Nathan Goodyear on 21 Mar 18
     
    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

Effect of high dose intravenous ascorbic acid on the level of inflammation in patients ... - 0 views

www.riordanclinic.org/...MRI-v01n02-p26.pdf

RA rheumatoid arthritis rheumatoid arthritis IV vitamin C intravenous IV vitamin C ascorbic vitamin C inflammation autoimmune

shared by Nathan Goodyear on 10 Dec 12 - No Cached
  • Nathan Goodyear on 10 Dec 12
     
    This study, small pilot, showed that they were able to lower inflammation in those suffering from RA, through high dose vitamin C IV therapy. This study stopped at 25 gms. The vitamin C is a scavenger of ROS and ROS stimulates inflammation through NF-kappaB. This is how vitamin C can reduce inflammation.
Nathan Goodyear

HIF-1-mediated metabolic reprogramming reduces ROS levels and facilitates the metastati... - 0 views

www.ncbi.nlm.nih.gov/...PMC3899644

Cancer HIF-1alpha HIF-1 ROS reactive oxygen species reactive oxygenation species

shared by Nathan Goodyear on 12 Dec 18 - No Cached
  • Nathan Goodyear on 12 Dec 18
     
    HIF-1alpha and ROS relationship in cancer
Nathan Goodyear

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

www.ncbi.nlm.nih.gov/...PMC3777479

Niclosamide cancer NF-kappaB Wnt ROS mTOR

shared by Nathan Goodyear on 16 Apr 18 - No Cached
  • 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
  • ...13 more annotations...
  • 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
  • Nathan Goodyear on 16 Apr 18
     
    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

Press-pulse: a novel therapeutic strategy for the metabolic management of cancer | Nutr... - 0 views

nutritionandmetabolism.biomedcentral.com/...s12986-017-0178-2

ketogenic diet ketogenic press-pulse hyperbaric oxygen therapy HBOTnutrition diet cancer HBOT IVC IV vitamin C DCA dichloracetic acid cancer therapy cancer treatment alternative cancer treatment

shared by Nathan Goodyear on 09 Jul 17 - No Cached
mamdouh_hfz liked it
  • A “press” disturbance was considered a chronic environmental stress on all organisms in an ecological community
  • “pulse” disturbances were considered acute events that disrupted biological communities to produce high mortality
  • Neoplasia involving dysregulated cell growth is the biological endpoint of the disease
  • ...84 more annotations...
  • Data from the American Cancer Society show that the rate of increase in cancer deaths/year (3.4%) was two-fold greater than the rate of increase in new cases/year (1.7%) from 2013 to 2017
  • cancer is predicted to overtake heart disease as the leading cause of death in Western societies
  • cancer can also be recognized as a metabolic disease.
  • glucose is first split into two molecules of pyruvate through the Embden–Meyerhof–Parnas glycolytic pathway in the cytosol
  • Aerobic fermentation, on the other hand, involves the production of lactic acid under normoxic conditions
  • persistent lactic acid production in the presence of adequate oxygen is indicative of abnormal respiration
  • Otto Warburg first proposed that all cancers arise from damage to cellular respiration
  • The Crabtree effect is an artifact of the in vitro environment and involves the glucose-induced suppression of respiration with a corresponding elevation of lactic acid production even under hyperoxic (pO2 = 120–160 mmHg) conditions associated with cell culture
  • the Warburg theory of insufficient aerobic respiration remains as the most credible explanation for the origin of tumor cells [2, 37, 51, 52, 53, 54, 55, 56, 57].
  • The main points of Warburg’s theory are; 1) insufficient respiration is the predisposing initiator of tumorigenesis and ultimately cancer, 2) energy through glycolysis gradually compensates for insufficient energy through respiration, 3) cancer cells continue to produce lactic acid in the presence of oxygen, and 4) respiratory insufficiency eventually becomes irreversible
  • Efraim Racker coined the term “Warburg effect”, which refers to the aerobic glycolysis that occurs in cancer cells
  • Warburg clearly demonstrated that aerobic fermentation (aerobic glycolysis) is an effect, and not the cause, of insufficient respiration
  • all tumor cells that have been examined to date contain abnormalities in the content or composition of cardiolipin
  • The evidence supporting Warburg’s original theory comes from a broad range of cancers and is now overwhelming
  • respiratory insufficiency, arising from any number mitochondrial defects, can contribute to the fermentation metabolism seen in tumor cells.
  • data from the nuclear and mitochondrial transfer experiments suggest that oncogene changes are effects, rather than causes, of tumorigenesis
  • Normal mitochondria can suppress tumorigenesis, whereas abnormal mitochondria can enhance tumorigenesis
  • In addition to glucose, cancer cells also rely heavily on glutamine for growth and survival
  • Glutamine is anapleurotic and can be rapidly metabolized to glutamate and then to α-ketoglutarate for entry into the TCA cycle
  • Glucose and glutamine act synergistically for driving rapid tumor cell growth
  • Glutamine metabolism can produce ATP from the TCA cycle under aerobic conditions
  • Amino acid fermentation can generate energy through TCA cycle substrate level phosphorylation under hypoxic conditions
  • Hif-1α stabilization enhances aerobic fermentation
  • targeting glucose and glutamine will deprive the microenvironment of fermentable fuels
  • Although Warburg’s hypothesis on the origin of cancer has created confusion and controversy [37, 38, 39, 40], his hypothesis has never been disproved
  • Warburg referred to the phenomenon of enhanced glycolysis in cancer cells as “aerobic fermentation” to highlight the abnormal production of lactic acid in the presence of oxygen
  • Emerging evidence indicates that macrophages, or their fusion hybridization with neoplastic stem cells, are the origin of metastatic cancer cells
  • Radiation therapy can enhance fusion hybridization that could increase risk for invasive and metastatic tumor cells
  • Kamphorst et al. in showing that pancreatic ductal adenocarcinoma cells could obtain glutamine under nutrient poor conditions through lysosomal digestion of extracellular proteins
  • It will therefore become necessary to also target lysosomal digestion, under reduced glucose and glutamine conditions, to effectively manage those invasive and metastatic cancers that express cannibalism and phagocytosis.
  • Previous studies in yeast and mammalian cells show that disruption of aerobic respiration can cause mutations (loss of heterozygosity, chromosome instability, and epigenetic modifications etc.) in the nuclear genome
  • The somatic mutations and genomic instability seen in tumor cells thus arise from a protracted reliance on fermentation energy metabolism and a disruption of redox balance through excess oxidative stress.
  • According to the mitochondrial metabolic theory of cancer, the large genomic heterogeneity seen in tumor cells arises as a consequence, rather than as a cause, of mitochondrial dysfunction
  • A therapeutic strategy targeting the metabolic abnormality common to most tumor cells should therefore be more effective in managing cancer than would a strategy targeting genetic mutations that vary widely between tumors of the same histological grade and even within the same tumor
  • Tumor cells are more fit than normal cells to survive in the hypoxic niche of the tumor microenvironment
  • Hypoxic adaptation of tumor cells allows for them to avoid apoptosis due to their metabolic reprograming following a gradual loss of respiratory function
  • The high rates of tumor cell glycolysis and glutaminolysis will also make them resistant to apoptosis, ROS, and chemotherapy drugs
  • Despite having high levels of ROS, glutamate-derived from glutamine contributes to glutathione production that can protect tumor cells from ROS
    • Nathan Goodyear
      Nathan Goodyear on 08 Feb 18
       
      reason to eliminate glutamine in cancer patients and even GSH with cancer patients
  • It is clear that adaptability to environmental stress is greater in normal cells than in tumor cells, as normal cells can transition from the metabolism of glucose to the metabolism of ketone bodies when glucose becomes limiting
  • Mitochondrial respiratory chain defects will prevent tumor cells from using ketone bodies for energy
  • glycolysis-dependent tumor cells are less adaptable to metabolic stress than are the normal cells. This vulnerability can be exploited for targeting tumor cell energy metabolism
  • In contrast to dietary energy reduction, radiation and toxic drugs can damage the microenvironment and transform normal cells into tumor cells while also creating tumor cells that become highly resistant to drugs and radiation
  • Drug-resistant tumor cells arise in large part from the damage to respiration in bystander pre-cancerous cells
  • Because energy generated through substrate level phosphorylation is greater in tumor cells than in normal cells, tumor cells are more dependent than normal cells on the availability of fermentable fuels (glucose and glutamine)
  • Ketone bodies and fats are non-fermentable fuels
  • Although some tumor cells might appear to oxidize ketone bodies by the presence of ketolytic enzymes [181], it is not clear if ketone bodies and fats can provide sufficient energy for cell viability in the absence of glucose and glutamine
  • Apoptosis under energy stress is greater in tumor cells than in normal cells
  • A calorie restricted ketogenic diet or dietary energy reduction creates chronic metabolic stress in the body
  • . This energy stress acts as a press disturbance
  • Drugs that target availability of glucose and glutamine would act as pulse disturbances
  • Hyperbaric oxygen therapy can also be considered another pulse disturbance
  • The KD can more effectively reduce glucose and elevate blood ketone bodies than can CR alone making the KD potentially more therapeutic against tumors than CR
  • Campbell showed that tumor growth in rats is greater under high protein (>20%) than under low protein content (<10%) in the diet
  • Protein amino acids can be metabolized to glucose through the Cori cycle
  • The fats in KDs used clinically also contain more medium chain triglycerides
  • Calorie restriction, fasting, and restricted KDs are anti-angiogenic, anti-inflammatory, and pro-apoptotic and thus can target and eliminate tumor cells through multiple mechanisms
  • Ketogenic diets can also spare muscle protein, enhance immunity, and delay cancer cachexia, which is a major problem in managing metastatic cancer
  • GKI values of 1.0 or below are considered therapeutic
  • The GKI can therefore serve as a biomarker to assess the therapeutic efficacy of various diets in a broad range of cancers.
  • It is important to remember that insulin drives glycolysis through stimulation of the pyruvate dehydrogenase complex
  • The water-soluble ketone bodies (D-β-hydroxybutyrate and acetoacetate) are produced largely in the liver from adipocyte-derived fatty acids and ketogenic dietary fat. Ketone bodies bypass glycolysis and directly enter the mitochondria for metabolism to acetyl-CoA
  • Due to mitochondrial defects, tumor cells cannot exploit the therapeutic benefits of burning ketone bodies as normal cells would
  • Therapeutic ketosis with racemic ketone esters can also make it feasible to safely sustain hypoglycemia for inducing metabolic stress on cancer cells
    • Nathan Goodyear
      Nathan Goodyear on 08 Feb 18
       
      Ketones are much more than energy adaptabilit, but actually are therapeutic.
  • ketone bodies can inhibit histone deacetylases (HDAC) [229]. HDAC inhibitors play a role in targeting the cancer epigenome
  • Therapeutic ketosis reduces circulating inflammatory markers, and ketones directly inhibit the NLRP3 inflammasome, an important pro-inflammatory pathway linked to carcinogenesis and an important target for cancer treatment response
  • Chronic psychological stress is known to promote tumorigenesis through elevations of blood glucose, glucocorticoids, catecholamines, and insulin-like growth factor (IGF-1)
  • In addition to calorie-restricted ketogenic diets, psychological stress management involving exercise, yoga, music etc. also act as press disturbances that can help reduce fatigue, depression, and anxiety in cancer patients and in animal models
  • Ketone supplementation has also been shown to reduce anxiety behavior in animal models
  • This physiological state also enhances the efficacy of chemotherapy and radiation therapy, while reducing the side effects
  • lower dosages of chemotherapeutic drugs can be used when administered together with calorie restriction or restricted ketogenic diets (KD-R)
  • Besides 2-DG, a range of other glycolysis inhibitors might also produce similar therapeutic effects when combined with the KD-R including 3-bromopyruvate, oxaloacetate, and lonidamine
    • Nathan Goodyear
      Nathan Goodyear on 08 Feb 18
       
      oxaloacetate is a glycolytic inhibitor, as is doxycycline, and IVC.
  • A synergistic interaction of the KD diet plus radiation was seen
  • It is important to recognize, however, that the radiotherapy used in glioma patients can damage the respiration of normal cells and increase availability of glutamine in the microenvironment, which can increase risk of tumor recurrence especially when used together with the steroid drug dexamethasone
  • Poff and colleagues demonstrated that hyperbaric oxygen therapy (HBOT) enhanced the ability of the KD to reduce tumor growth and metastasis
  • HBOT also increases oxidative stress and membrane lipid peroxidation of GBM cells in vitro
  • The effects of the KD and HBOT can be enhanced with administration of exogenous ketones, which further suppressed tumor growth and metastasis
  • Besides HBOT, intravenous vitamin C and dichloroacetate (DCA) can also be used with the KD to selectively increase oxidative stress in tumor cells
  • Recent evidence also shows that ketone supplementation may enhance or preserve overall physical and mental health
  • Some tumors use glucose as a prime fuel for growth, whereas other tumors use glutamine as a prime fuel [102, 186, 262, 263, 264]. Glutamine-dependent tumors are generally less detectable than glucose-dependent under FDG-PET imaging, but could be detected under glutamine-based PET imaging
  • GBM and use glutamine as a major fuel
  • Many of the current treatments used for cancer management are based on the view that cancer is a genetic disease
  • Emerging evidence indicates that cancer is a mitochondrial metabolic disease that depends on availability of fermentable fuels for tumor cell growth and survival
  • Glucose and glutamine are the most abundant fermentable fuels present in the circulation and in the tumor microenvironment
  • Low-carbohydrate, high fat-ketogenic diets coupled with glycolysis inhibitors will reduce metabolic flux through the glycolytic and pentose phosphate pathways needed for synthesis of ATP, lipids, glutathione, and nucleotides
  • Nathan Goodyear on 09 Jul 17
     
    Cancer is a mitochondrial disease? So says the well published Dr Seyfried. Glucose and glutamine drive cancer growth.
Nathan Goodyear

Toxicity of the spike protein of COVID-19 is a redox shift phenomenon: A novel therapeu... - 0 views

www.sciencedirect.com/...S0891584923005014

COVID19 COVID-19 cancer inflammation SARS-CoV-2 spike proteins COVID spikeopathy

shared by Nathan Goodyear on 01 Sep 23 - No Cached
  • Redox shift is due to Warburg effect and mitochondrial impairment.
  • Redox shift is due to Warburg effect and mitochondrial impairment.
  • Redox shift is due to Warburg effect and mitochondrial impairment.
  • ...88 more annotations...
  • The cytokine storm is a consequence of mitochondrial dysfunction
  • The cytokine storm is a consequence of mitochondrial dysfunction
  • The cytokine storm is a consequence of mitochondrial dysfunction
  • The cytokine storm is a consequence of mitochondrial dysfunction
  • Lipoic acid, Methylene Blue and Chlorine dioxide relieve COVID-19 spike protein toxicity
  • Lipoic acid, Methylene Blue and Chlorine dioxide relieve COVID-19 spike protein toxicity
  • Lipoic acid, Methylene Blue and Chlorine dioxide relieve COVID-19 spike protein toxicity
  • Lipoic acid, Methylene Blue and Chlorine dioxide relieve COVID-19 spike protein toxicity
  • most diseases display a form of anabolism due to mitochondrial impairment
  • most diseases display a form of anabolism due to mitochondrial impairment
  • most diseases display a form of anabolism due to mitochondrial impairment
  • infection by Covid-19 follows a similar pattern
  • chronic inflammation
  • Long-term effects include redox shift and cellular anabolism as a result of the Warburg effect and mitochondrial dysfunction
  • Long-term effects include redox shift and cellular anabolism as a result of the Warburg effect and mitochondrial dysfunction
  • Long-term effects include redox shift and cellular anabolism as a result of the Warburg effect and mitochondrial dysfunction
  • Long-term effects include redox shift and cellular anabolism as a result of the Warburg effect and mitochondrial dysfunction
  • infection by Covid-19 follows a similar pattern
  • unrelenting anabolism leads to the cytokine storm,
  • unrelenting anabolism leads to the cytokine storm,
  • unrelenting anabolism leads to the cytokine storm,
  • chronic inflammation
  • chronic inflammation
  • infection by Covid-19 follows a similar pattern
  • Lipoic acid and Methylene Blue have been shown to enhance the mitochondrial activity, relieve the Warburg effect and increase catabolism
  • Lipoic acid and Methylene Blue have been shown to enhance the mitochondrial activity, relieve the Warburg effect and increase catabolism
  • Lipoic acid and Methylene Blue have been shown to enhance the mitochondrial activity, relieve the Warburg effect and increase catabolism
  • Methylene Blue, Chlorine dioxide and Lipoic acid may help reduce long-term Covid-19 effects by stimulating the catabolism
  • Methylene Blue, Chlorine dioxide and Lipoic acid may help reduce long-term Covid-19 effects by stimulating the catabolism
  • Methylene Blue, Chlorine dioxide and Lipoic acid may help reduce long-term Covid-19 effects by stimulating the catabolism
  • direct consequence of redox iMeBalance, itself a consequence of decreased energy yield by the mitochondria
  • direct consequence of redox iMeBalance, itself a consequence of decreased energy yield by the mitochondria
  • mitochondrial dysfunction and increased levels of lactate, which are important characteristics of metabolic shift and Warburg effect in many diseases
  • mitochondrial dysfunction and increased levels of lactate, which are important characteristics of metabolic shift and Warburg effect in many diseases
  • increased lactate dehydrogenase activity (LDH) was observed in COVID-19 patients
  • increased lactate dehydrogenase activity (LDH) was observed in COVID-19 patients
  • almost every disease presents an increased anabolism
  • almost every disease presents an increased anabolism
  • cell division is the most sophisticated way to release entropy
  • cell division is the most sophisticated way to release entropy
    • Nathan Goodyear
      Nathan Goodyear on 01 Sep 23
       
      Wow
    • Nathan Goodyear
      Nathan Goodyear on 01 Sep 23
       
      Wow
  • transition from catabolism to anabolism is driven by a redox shift
  • transition from catabolism to anabolism is driven by a redox shift
  • viral spike protein binds to ACE2 receptor of the host cell [22,23].
  • redox signaling plays an important role in regulating immune function and inflammation, and disruptions in this signaling can lead to excessive cytokine production and immune system activation
  • Aging is associated with a poor control of the redox balance
  • thiol/disulfide homeostasis
  • reduced extracellular environment in the elderly and the increased susceptibility to Covid-19 infection
  • reduced extracellular environment in the elderly and the increased susceptibility to Covid-19 infection
  • Redox signaling tightly modulates the inflammatory response and oxidative stress has been reported in acute Covid-19
  • People at high risk are the elderly, patients suffering from metabolic syndrome such as obesity, or those suffering from chronic diseases such as cancer or inflammation
  • COVID-19 patients with severe disease have higher levels of oxidative stress markers and lower antioxidant levels
  • oxidative stress can activate the NLRP3 inflammasome, which is a protein complex that plays a key role in the cytokine storm
  • inflammation leads to the formation of ROS and RNS, while redox iMeBalance results in cellular damage, which in turn triggers an inflammatory response
  • persistently elevated mtROS triggers endothelial dysfunction and inflammation, which results in a vicious loop involving ROS, inflammation, and mitochondrial dysfunction
  • Damaged mitochondria releasing ROS induce inflammation via the NLRP3 inflammasome
  • Damaged mitochondria releasing ROS induce inflammation via the NLRP3 inflammasome
  • reduced environment during the cytokine storm
  • IL-2 is highly up-regulated in Covid-19 patients [37], and IL-2 is known to significantly stimulate the generation of NO in patients
  • Nitric acid is also the key mediator of IL-2-induced hypotension and vascular leak syndrome
  • mitochondrial dysfunction has been linked to the pathogenesis of Covid-19
  • mitochondrial dysfunction triggered by SARS-CoV-2 leads to damage to the mitochondria
  • mitochondrial dysfunction triggered by SARS-CoV-2 leads to damage to the mitochondria
  • As catabolism is decreased, entropy is released through anabolism
  • Elevated levels of lactate, a characteristic of the Warburg effect, were also reported in the high-risk Covid-19
  • elevated levels of ventricular lactic acid consistent with oxidative stress
  • A decrease of ΔΨm is implicated in several inflammation-related diseases
  • decrease in ΔΨm in leucocytes from Covid-19 patients
  • vaccinated with RNA or DNA vaccines triggering the synthesis of the viral spike protein in human cells
  • viral reactivation in varicella-zoster virus [55] or hepatitis [56], coagulopathy and resulting stroke and myocarditis following both DNA-based vaccines [57] and RNA-based vaccines
  • Covid-19, mitochondrial impairment
  • characteristic of the Warburg effect is present in almost every disease and appears to be a central feature in most of the hallmarks of cancer
  • inflammation, mitochondrial dysfunction and increased lactate concentrations in the extracellular fluid
  • In Covid-19, like any inflammation, there is a metabolic rewiring where cells rely on glycolysis
  • As the mitochondria are impaired, the infected cell cannot catabolize efficiently. It will release lactic acid in the blood stream
    • Nathan Goodyear
      Nathan Goodyear on 01 Sep 23
       
      Mitochondrial impairment
  • Striking similarities are seen between cancer, Alzheimer's disease and Covid-19, all related to the Warburg effect
  • Cancer, inflammation, Alzheimer's, and Parkinson's diseases share a common peculiarity, the inability of the cell to export entropy outside the body in the harmless form of heat
    • Nathan Goodyear
      Nathan Goodyear on 01 Sep 23
       
      Entropy: lack of order or predictability; gradual decline into disorder.
  • MEB relieves the Warburg effect [87], improves memory [77], is active in the treatment of depressive episodes [79,80] and reduces the importance of ischemic strokes
  • MEB relieves the Warburg effect [87], improves memory [77], is active in the treatment of depressive episodes [79,80] and reduces the importance of ischemic strokes
  • MEB has been shown to inhibit SARS-Cov-2 replication in vitro
  • MEB has been shown to inhibit SARS-Cov-2 replication in vitro
  • It has been shown that Covid-19-patients treated with MEB, have a significant reduction in hospital stay duration and mortality
  • MeB is an acceptor-donor molecule
  • MeB + can take a pair of electrons (of H atoms) and MeBH can release this pair easily, so that MeB is partially recycled like a catalyst
  • MeB acts as an electron bridge between a donor (FADH2, FMNH, NADH) and an acceptor (complex IV of ETC or oxygen itself)
  • As a coenzyme of pyruvate dehydrogenase (PDH), alpha-lipoic acid (ALA) initiates the formation of acetyl-CoA to feed the TCA cycle
  • ALA enhances the catabolism of carbon. cycle and therefore may reduce the Warburg effect and consequently, lactate production
  • Methylene Blue plays a similar role after the TCA cycle, by carrying electrons to complex IV of the electron transport chain
  • Drugs such as lipoic acid and MeB, which target the metabolism, decrease the redox shift by increasing catabolism
Nathan Goodyear

High-Dose Vitamin C for Cancer Therapy - PMC - 0 views

www.ncbi.nlm.nih.gov/...PMC9231292

vitamin C cancer

shared by Nathan Goodyear on 27 Jul 22 - No Cached
  • diabetes [8], atherosclerosis [9], the common cold [10], cataracts [11], glaucoma [12], macular degeneration [13], stroke [14], heart disease [15], COVID-19 [16], and cancer.
  • 1–5% of the Vit-C inside the human cells
  • interaction between Fe(II) and H2O2 produces OH− through the Fenton reaction
  • ...35 more annotations...
  • metabolic activity, oxygen transport, and DNA synthesis
  • Iron is found in the human body in the form of haemoglobin in red blood cells and growing erythroid cells.
  • macrophages contain considerable quantities of iron
  • iron is taken up by the majority of cells in the form of a transferrin (Tf)-Fe(III) complex that binds to the cell surface receptor transferrin receptor 1 (TfR1)
  • excess iron is retained in the liver cells
  • the endosomal six transmembrane epithelial antigen of the prostate 3 (STEAP3) reduces Fe(III) (ferric ion) to Fe(II) (ferrous ion), which is subsequently transferred across the endosomal membrane by divalent metal transporter 1 (DMT1)
  • labile iron pool (LIP)
  • LIP is toxic to the cells owing to the production of massive amounts of ROS.
  • DHA is quickly converted to Vit-C within the cell, by interacting with reduced glutathione (GSH) [45,46,47]. NADPH then recycles the oxidized glutathione (glutathione disulfide (GSSG)) and converts it back into GSH
  • Fe(II) catalyzes the formation of OH• and OH− during the interaction between H2O2 and O2•− (Haber–Weiss reaction)
  • Ascorbate can efficiently reduce free iron, thus recycling the cellular Fe(II)/Fe(III) to produce more OH• from H2O2 than can be generated during the Fenton reaction, which ultimately leads to lipid, protein, and DNA oxidation
  • Vit-C-stimulated iron absorption
  • reduce cellular iron efflux
  • high-dose Vit-C may elevate cellular LIP concentrations
  • ascorbate enhanced cancer cell LIP specifically by generating H2O2
  • Vit-C produces H2O2 extracellularly, which in turn inhibits tumor cells immediately
  • tumor cells have a need for readily available Fe(II) to survive and proliferate.
  • Tf has been recognized to sequester most labile Fe(II) in vivo
  • Asc•− and H2O2 were generated in vivo upon i.v Vit-C administration of around 0.5 g/kg of body weight and that the generation was Vit-C-dose reliant
  • free irons, especially Fe(II), increase Vit-C autoxidation, leading to H2O2 production
  • iron metabolism is altered in malignancies
  • increase in the expression of various iron-intake pathways or the downregulation of iron exporter proteins and storage pathways
  • Fe(II) ion in breast cancer cells is almost double that in normal breast tissues
  • macrophages in the cancer microenvironment have been revealed to increase iron shedding
  • Advanced breast tumor patients had substantially greater Fe(II) levels in their blood than the control groups without the disease
  • increased the amount of LIP inside the cells through transferrin receptor (TfR)
  • Warburg effect, or metabolic reprogramming,
  • Warburg effect is aided by KRAS or BRAF mutations
  • Vit-C is supplied, it oxidizes to DHA, and then is readily transported by GLUT-1 in mutant cells of KRAS or BRAF competing with glucose [46]. DHA is quickly converted into ascorbate inside the cell by NADPH and GSH [46,107]. This decrease reduces the concentration of cytosolic antioxidants and raises the intracellular ROS amounts
  • increased ROS inactivates glyceraldehyde 3-phosphate dehydrogenase (GAPDH)
  • ROS activates poly (ADP-ribose) polymerase (PARP), which depletes NAD+ (a critical co-factor of GAPDH); thus, further reducing the GAPDH associated with a multifaceted metabolic rewiring
  • Hindering GAPDH can result in an “energy crisis”, due to the decrease in ATP production
  • high-dose Vit-C recruited metabolites and increased the enzymatic activity in the pentose phosphate pathway (PPP), blocked the tri-carboxylic acid (TCA) cycle, and increased oxygen uptake, disrupting the intracellular metabolic balance and resulting in irreversible cell death, due to an energy crisis
  • mega-dose Vit-C influences energy metabolism by producing tremendous amounts of H2O2
  • Due to its great volatility at neutral pH [76], bolus therapy with mega-dose DHA has only transitory effects on tumor cells, both in vitro and in vivo.
Nathan Goodyear

Homocysteine and Endothelial Dysfunction: A Link with Cardiovascular Disease - 0 views

jn.nutrition.org/...369.full.pdf+html

homocysteine CVD endothelial dysfunction cardiovascular disease ROS reactive oxygen species

shared by Nathan Goodyear on 25 Sep 12 - No Cached
  • Nathan Goodyear on 25 Sep 12
     
    No surprise that homocysteine is associated with vascular dysfunction, when elevated;  But the mechanism is elucidated here through ROS generation.
Nathan Goodyear

European Journal of Clinical Nutrition - C-reactive protein concentration and concentra... - 0 views

www.nature.com/...1601667a.html

IV vitamin C intravenous IV vitamin C antioxidants CRP ROS vitamins

shared by Nathan Goodyear on 10 Dec 12 - No Cached
  • Nathan Goodyear on 10 Dec 12
     
    This study shows that inflammation, CRP in this study, was inversely associated with low antioxidants ie. vitamin C.  This makes since as ROS are known to stimulate inflammation.  Vitamin C should be considered as a therapeutic option in those with inflammation.
Nathan Goodyear

American College of Cardiology Foundation | Journal of the American College of Cardiolo... - 0 views

content.onlinejacc.org/article.aspx

mitochondria oxidative stress heart failure heart

shared by Nathan Goodyear on 19 Mar 13 - No Cached
  • Although currently no drugs that specifically target mitochondrial biogenesis in HF are available, acceleration of this process through adenosine monophosphate–activated kinase (AMPK), endothelial nitric oxide synthase (eNOS), and other pathways may represent a promising therapeutic approach
  • Mitochondrial biogenesis can be enhanced therapeutically with the use of adenosine monophosphate kinase (AMPK) agonists, stimulants of nitric oxide/cyclic guanosine monophosphate (NO/cGMP) pathway (including phosphodiesteraes type 5 inhibitors), or resveratrol
  • metformin, a commonly used antidiabetic drug that activates AMPK signaling
  • ...10 more annotations...
  • Recent evidence suggests that the eNOS/NO/cGMP pathway is an important activator of mitochondrial biogenesis
  • BH4 (tetrahydrobiopterin) supplementation can prevent eNOS uncoupling and was found to reduce left ventricular hypertrophy
  • folic acid is known to replenish reduced BH4 and has been shown to protect the heart through increased eNOS activity
  • epidemiological studies reveal a reduced risk of cardiovascular disease in premenopausal, but not post-menopausal, women compared with men
  • Resveratrol, a polyphenol compound responsible for the cardioprotective properties of red wine, was recently identified as a potent stimulator of mitochondrial biogenesis
  • Both folate deficiency and inhibition of BH4 synthesis were associated with reduced mitochondrial number and function
  • post-menopausal women
    • Nathan Goodyear
      Nathan Goodyear on 19 Mar 13
       
      I would hypothesis that a change in the predominance of ER expression is one of ER beta to ER alpha: creating a more pro-inflammatory signal.
  • The majority of ROS in the heart appear to come from uncoupling of mitochondrial electron transport chain at the level of complexes I and III
  • Because the majority of ROS in HF comes from mitochondria, these organelles are the primary target of oxidative damage.
  • cardioprotective therapies such as angiotensin-converting enzyme inhibitors and ATII receptor blockers were shown to possess antioxidant properties, although it is not known whether they target mitochondrial ROS directly or indirectly
  • Nathan Goodyear on 19 Mar 13
     
    great review of mitochondrial biogenesis, oxidative stress and heart failure.  
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