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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
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  • 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

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
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  • 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

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

Oncotarget | NADH autofluorescence, a new metabolic biomarker for cancer stem cells: Id... - 0 views

www.oncotarget.com/index.php

vitamin C IV vitamin C cancer cancer stem cells milk thistle silymarin ascorbic acid bee propolis CAPE glycolytic inhibitor natural

shared by Nathan Goodyear on 08 Dec 17 - No Cached
  • Vitamin C was ~10 times more potent than 2-DG for the targeting of CSCs
  • Cancer stem-like cells (CSCs) are thought to be the root cause of chemotherapy-resistance and radio-resistance
  • ultimately leading to treatment failure in patients with advanced disease [1-3]. They have been directly implicated mechanistically in tumor recurrence and metastasis, resulting in poor patient survival
  • ...26 more annotations...
  • mitochondrial biogenesis may be a key driver of the CSC phenotype
  • Our results indicate that increased mitochondrial oxidative stress and high NADH levels are both key characteristics of the CSC metabolic phenotype
  • high levels of NAD(P)H auto-fluorescence are known to be a surrogate marker for mitochondrial “power”, high OXPHOS capacity and increased ATP production
  • CSCs may be strictly dependent on NAD(P)H to maintain their enhanced mitochondrial function
  • an intact NAD+ salvage pathway is strictly required for mammosphere formation, supporting our results using NAD(P)H auto-fluorescence, which enriched CSC activity by more than 5-fold.
  • Since glycolysis is especially critical for maintaining the TCA cycle, OXPHOS and overall mitochondrial function, we next assessed the effects of known glycolytic inhibitors
  • we show that two other natural products that function as effective glycolysis inhibitors, also inhibited mammosphere formation. More specifically, vitamin C (ascorbic acid), which induces oxidative stress and inhibits the activity of GAPDH (a key glycolytic enzyme) [17], also inhibited mammosphere formation, with an IC-50 of 1 mM (Figure 7B). Therefore, vitamin C was ~10 times more potent than 2-DG at targeting CSC propagation
  • silibinin (the major active constituent of silymarin, an extract of milk thistle seeds) [18], which specifically functions as an inhibitor of glucose uptake, blocked mammosphere formation, with an IC-50 between 200 and 400 µM
  • caffeic acid phenyl ester (CAPE), a key component of honey-bee propolis, has potent anti-cancer properties
  • Propolis has a strong history of medicinal use, dating back more than 2,000 years
  • Because of it aromatic ring structure (Figure 8), we speculated that CAPE might function as a potent inhibitor of oxidative mitochondrial metabolism
  • CAPE quantitatively inhibits the mitochondrial oxygen consumption rate (OCR) and, in turn, induces the onset of aerobic glycolysis (ECAR)
  • CAPE shows a clear selectivity for targeting CSCs and adherent cancer cells, relative to normal fibroblasts.
  • CAPE functions as a “natural” mitochondrial OXPHOS inhibitor, that preferentially targets the CSC sub-population. This could explain CAPE’s known anti-cancer properties
  • Our data directly shows that a small fraction of the total cell population, characterized by increased PGC1α activity, high mitochondrial ROS/H2O2 and high NADH levels, has the ability to survive and grow under anchorage-independent conditions, driving mammosphere formation
  • We highlight the utility of certain natural products, such as Silibinin, Vitamin C and CAPE, that could be used to therapeutically target CSCs. Silibinin is the major active component of silymarin, which is an extract prepared from milk thistle seeds.
  • high NADH is a property that is conserved between normal and cancerous stem cells
  • Previous studies have also shown that when non-CSCs and CSCs are both fed mitochondrial fuels (such as L-lactate or ketone bodies), that CSCs quantitatively produce more NADH in response to this stimulus
  • CSCs may be strictly dependent on NADH to maintain their enhanced mitochondrial function
  • The Noble Prize winner, Linus Pauling, was among the first to describe and clinically test the efficacy of Vitamin C, as a relatively non-toxic anti-cancer agent
  • Vitamin C has two mechanisms of action. First, it is a potent pro-oxidant, that actively depletes the reduced glutathione pool, leading to cellular oxidative stress and apoptosis in cancer cells. Moreover, it also behaves as an inhibitor of glycolysis, by targeting the activity of GAPDH, a key glycolytic enzyme.
  • Here, we show that Vitamin C can also be used to target the CSC population, as it is an inhibitor of energy metabolism that feeds into the mitochondrial TCA cycle and OXPHOS
  • Vitamin C may prove to be promising agent for new clinical trials, aimed at testing its ability to reduce CSC activity in cancer patients, as an add-on to more conventional therapies, to prevent tumor recurrence, further disease progression and metastasis
  • Interestingly, a breast cancer based clinical study has already shown that the use of Vitamin C, concurrent with or within 6 months of chemotherapy, significantly reduces both tumor recurrence and patient mortality
  • CAPE quantitatively reduces mitochondrial oxygen consumption (OCR), while inducing a reactive increase in glycolysis (ECAR). As such, it potently inhibits mammosphere formation with an IC-50 of ~2.5 µM. Similarly, it also significantly inhibits cell migration
  • we also demonstrate that 7 different inhibitors of key energetic pathways can be used to effectively block CSC propagation, including three natural products (silibinin, ascorbic acid and CAPE). Future studies will be necessary to test their potential for clinical benefit in cancer patients.
  • Nathan Goodyear on 08 Dec 17
     
    The future of cancer therapy is cancer stem cells.  Study finds that Vitamin C, silymarin, and bee propolis blocks mitochondrial energy pathways in cancer stem cells.  Vitamin C is a known glycolytic inhbitor. Vitamin C was found to inhibit glycolysis via GAPDH targeting to inhibit the energy pathways of the mitochondria in CSCs.  The authors propse that Vitamin C can be used as add on therapies for conventional therapies to specifically attack the CSCs and their contribution to recrurence, treatment resistance, and metastasis potential all in addition to the ability of vitamin C to reduce the side effects of chemotherapy.
Nathan Goodyear

Metabolic management of brain cancer - 0 views

www.sciencedirect.com/...S0005272810006857

brain cancer

shared by Nathan Goodyear on 17 Jun 13 - No Cached
  • Glutamine is a major metabolic fuel for both brain tumor cells and tumor-associated macrophages (TAMs)
  • the malignant phenotype of brain tumor cells that survive radiotherapy is often greater than that of the cells from the original tumor.
  • Conventional chemotherapy has faired little better than radiation therapy for the long-term management of malignant brain cancer
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  • most conventional radiation and brain cancer chemotherapies can enhance glioma energy metabolism and invasive properties, which would contribute to tumor recurrence and reduced patient survival [34].
  • We contend that all cancer regardless of tissue or cellular origin is a disease of abnormal energy metabolism
  • complex disease phenotypes can be managed through self-organizing networks that display system wide dynamics involving oxidative and non-oxidative (substrate level) phosphorylation
  • As long as brain tumors are provided a physiological environment conducive for their energy needs they will survive; when this environment is restricted or abruptly changed they will either grow slower, growth arrest, or perish [8] and [19]
  • New information also suggests that ketones are toxic to some human tumor cells and that ketones and ketogenic diets might restrict availability of glutamine to tumor cells [68], [69] and [70].
  • The success in dealing with environmental stress and disease is therefore dependent on the integrated action of all cells in the organism
  • Tumor cells survive in hypoxic environments not because they have inherited genes making them more fit or adaptable than normal cells, but because they have damaged mitochondria and have thus acquired the ability to derive energy largely through substrate level phosphorylation
  • Cancer cells survive and multiply only in physiological environments that provide fuels (mostly glucose and glutamine) subserving their requirement for substrate level phosphorylation
  • Integrity of the inner mitochondrial membrane is necessary for ketone body metabolism since β-hydroxybutyrate dehydrogenase, which catalyzes the first step in the metabolism of β-OHB to acetoacetate, interacts with cardiolipin and other phospholipids in the inner membrane
  • the mitochondria of many gliomas and most tumors for that matter are dysfunctional
  • Cardiolipin is essential for efficient oxidative energy production and mitochondrial function
  • Any genetic or environmental alteration in the content or composition of cardiolipin will compromise energy production through oxidative phosphorylation
  • The Crabtree effect involves the inhibition of respiration by high levels of glucose
  • the Warburg effect involves elevated glycolysis from impaired oxidative phosphorylation
  • the Crabtree effect can be reversible, the Warburg effect is largely irreversible because its origin is with permanently damaged mitochondria
  • The continued production of lactic acid in the presence of oxygen is the metabolic hallmark of most cancers and is referred to as aerobic glycolysis or the Warburg effect
  • We recently described how the retrograde signaling system could induce changes in oncogenes and tumor suppressor genes to facilitate tumor cell survival following mitochondrial damage [48].
  • In addition to glycolysis, glutamine can also increase ATP production under hypoxic conditions through substrate level phosphorylation in the TCA cycle after its metabolism to α-ketoglutarate
  • mitochondrial lipid abnormalities, which alter electron transport activities, can account in large part for the Warburg effect
  • targeting both glucose and glutamine metabolism could be effective for managing most cancers including brain cancer
  • The bulk of experimental evidence indicates that mitochondria are dysfunctional in tumors and incapable of generating sufficient ATP through oxidative phosphorylation
  • Cardiolipin defects in tumor cells are also associated with reduced activities of several enzymes of the mitochondrial electron transport chain making it unlikely that tumor cells with cardiolipin abnormalities can generate adequate energy through oxidative phosphorylation
  • The Crabtree effect involves the inhibition of respiration by high levels of glucose
  • Warburg effect involves elevated glycolysis from impaired oxidative phosphorylation
  • TCA cycle substrate level phosphorylation could therefore become another source of ATP production in tumor cells with impairments in oxidative phosphorylation
  • Caloric restriction, which lowers glucose and elevates ketone bodies [63] and [64], improves mitochondrial respiratory function and glutathione redox state in normal cells
  • DR naturally inhibits glycolysis and tumor growth by lowering circulating glucose levels, while at the same time, enhancing the health and vitality of normal cells and tissues through ketone body metabolism
  • DR is anti-angiogenic
  • DR also reduces angiogenesis in prostate and breast cancer
  • We suggest that apoptosis resistance arises largely from enhanced substrate level phosphorylation of tumor cells and to the genes associated with elevated glycolysis and glutaminolysis, e.g., c-Myc, Hif-1a, etc, which inhibit apoptosis
  • Modern medicine has not looked favorably on diet therapies for managing complex diseases especially when well-established procedures for acceptable clinical practice are available, regardless of how ineffective these procedures might be in managing the disease
  • More than 60 years of clinical research indicates that such approaches are largely ineffective in extending survival or improving quality of life
  • The process is rooted in the well-established scientific principle that tumor cells are largely dependent on substrate level phosphorylation for their survival and growth
  • Glucose and glutamine drive substrate level phosphorylation
  • targeting the glycolytically active tumor cells that produce pro-cachexia molecules, restricted diet therapies can potentially reduce tumor cachexia
  • It is important to recognize, however, that “more is not better” with respect to the ketogenic diet
  • Blood glucose ranges between 3.0 and 3.5 mM (55–65 mg/dl) and β-OHB ranges between 4 and 7 mM should be effective for tumor management
  • Nathan Goodyear on 17 Jun 13
     
    Dr Seyfriend presents his metabolic approach to the treatment of brain cancer.
Nathan Goodyear

Oncotarget | Vitamin C and Doxycycline: A synthetic lethal combination therapy targetin... - 0 views

www.impactjournals.com/...index.php

cancer doxycycline IV vitamin C vitamin C

shared by Nathan Goodyear on 14 Jun 17 - No Cached
  • These eight distinct cancer types included: DCIS, breast (ER(+) and ER(-)), ovarian, prostate, lung, and pancreatic carcinomas, as well as melanoma and glioblastoma. Doxycycline was also effective in halting the propagation of primary cultures of CSCs from breast cancer patients, with advanced metastatic disease (isolated from ascites fluid and/or pleural effusions)
  • Doxycycline behaves as a strong radio-sensitizer, successfully overcoming radio-resistance in breast CSCs
  • cancer cells can indeed escape the effects of Doxycycline, by reverting to a purely glycolytic phenotype. Fortunately, the metabolic inflexibility conferred by this escape mechanism allows Doxycycline-resistant (DoxyR) CSCs to be more effectively targeted with many other metabolic inhibitors, including Vitamin C, which functionally blocks aerobic glycolysis
  • ...36 more annotations...
  • Vitamin C inhibits GAPDH (a glycolytic enzyme) and depletes the cellular pool of glutathione, resulting in high ROS production and oxidative stress
  • DoxyR CSCs are between 4- to 10-fold more susceptible to the effects of Vitamin C
  • Doxycycline and Vitamin C may represent a new synthetic lethal drug combination for eradicating CSCs, by ultimately targeting both mitochondrial and glycolytic metabolism
  • inhibiting their propagation in the range of 100 to 250 µM
  • metabolic flexibility in cancer cells allows them to escape therapeutic eradication, leading to chemo- and radio-resistance
  • used doxycycline to pharmacologically induce metabolic inflexibility in CSCs, by chronically inhibiting mitochondrial biogenesis
  • This treatment resulted in a purely glycolytic population of surviving cancer cells
  • DoxyR cells are mainly glycolytic
  • MCF7 cells survive and develop Doxycycline-resistance, by adopting a purely glycolytic phenotype
  • Cancer stem cells (CSCs) are thought to be the “root cause” of tumor recurrence, distant metastasis and therapy-resistance
  • the conserved evolutionary similarities between aerobic bacteria and mitochondria, certain classes of antibiotics inhibit mitochondrial protein translation, as an off-target side-effect
  • Vitamin C was more potent than 2-DG; it inhibited DoxyR CSC propagation by > 90% at 250 µM and 100% at 500 µM
  • IC-50
  • DoxyR CSCs are between 4- to 10-fold more sensitive to Vitamin C than control MCF7 CSCs
  • Berberine, which is a naturally occurring antibiotic that also behaves as an OXPHOS inhibitor
  • treatment with Berberine effectively inhibited the propagation of the DoxyR CSCs by > 50% at 1 µM and > 80% at 10 µM.
  • Doxycycline, a clinically approved antibiotic, induces metabolic stress in cancer cells. This allows the remaining cancer cells to be synchronized towards a purely glycolytic phenotype, driving a form of metabolic inflexibility
  • Doxycycline-driven aerobic glycolysis
  • new synthetic lethal strategy for eradicating CSCs, by employing i) Doxycycline (to target mitochondria) and ii) Vitamin C (to target glycolysis)
  • Doxycycline inhibits mitochondrial biogenesis and OXPHOS,
  • hibits glycolytic metabolism by targeting and inhibiting the enzyme GAPDH
  • CSCs act as the main promoter of tumor recurrence and patient relapse
  • a metabolic shift from oxidative to glycolytic metabolism represents an escape mechanism for breast cancer cells chronically-treated with a mitochondrial stressor like Doxycycline, as mitochondrial dys-function leads to a stronger dependence on glucose
  • Vitamin C has been demonstrated to selectively kill cancer cells in vitro and to inhibit tumor growth in experimental mouse models
  • many of these actions have been attributed to the ability of Vitamin C to act as a glycolysis inhibitor, by targeting GAPDH and depleting the NAD pool
  • here we show that DoxyR CSCs are more vulnerable to the inhibitory effects of Vitamin C, at 4- to 10-fold lower concentrations, between 100 to 250 μM
  • concurrent use of Vitamin C, with standard chemotherapy, reduces tumor recurrence and patient mortality
  • after oral administration, Vitamin C plasma levels reach concentrations of ~70-220 μM
  • intravenous administration results in 30- to 70- fold higher plasma concentrations of Vitamin C
  • pro-oxidant activity results from Vitamin C’s action on metal ions, which generates free radicals and hydrogen peroxide, and is associated with cell toxicity
  • it has been shown that high-dose Vitamin C is more cytotoxic to cancer cells than to normal cells
  • This selectivity appears to be due to the higher catalase content observed in normal cells (~10-100 fold greater), as compared to tumor cells. Hence, Vitamin C may be regarded as a safe agent that selectively targets cancer cells
  • the concurrent use of Doxycycline and Vitamin C, in the context of this infectious disease, appeared to be highly synergistic in patients
  • Goc et al., 2016, showed that Doxycycline is synergistic in vitro with certain phytochemicals and micronutrients, including Vitamin C, in the in vitro killing of the vegetative spirochete form of Borrelia spp., the causative agent underlying Lyme disease
  • Doxycycline, an FDA-approved antibiotic, behaves as an inhibitor of mitochondrial protein translation
  • CSCs successfully escape from the anti-mitochondrial effects of Doxycycline, by assuming a purely glycolytic phenotype. Therefore, DoxyR CSCs are then more susceptible to other metabolic perturbations, because of their metabolic inflexibility
  • Nathan Goodyear on 14 Jun 17
     
    Not especially new, but IV vitamin C + daily doxycycline found to kill cancer stem cells.
Nathan Goodyear

Estradiol-17β Upregulates Pyruvate Kinase M2 Expression to Coactivate Estroge... - 0 views

press.endocrine.org/...jc.2013-2639

Estradiol ER alpha ER-alpha women female hormone hormones aerobic glycolysis Warburg effect estrogen

shared by Nathan Goodyear on 07 Oct 14 - No Cached
  • Nathan Goodyear on 07 Oct 14
     
    This is an important study.  Study found that Estradiol increased the transcription of pyruvate kinase M (PKM2)production in endometrial stromal cells.  This increase in PKM2 shifted metabolism to a aerobic glycolysis pattern similar to the Warburg effect described in cancer.  Additionally, increased PKM2 via Estradiol increased ER alpha transcription and functioned as a ER alpha coactivator.
Nathan Goodyear

British Journal of Cancer - Dichloroacetate inhibits aerobic glycolysis in multiple mye... - 0 views

www.nature.com/...bjc2013120a.html

DCA dichloroacetate cancer

shared by Nathan Goodyear on 19 Nov 14 - No Cached
  • Nathan Goodyear on 19 Nov 14
     
    Dichloroacetate (DCA) inhibits aerobic glycolysis via inhibition of Pyruvate Dehydrogenase kinase (PDK), which allows for the phosphorylation of Pyruvate Dehydrogenase and the formation of acetylCo-A.  This then feeds the krebs cycle.  Increased mitochondrial activity increases ROS and resultant apoptosis of cancer cells.
Nathan Goodyear

KoreaMed Synapse - 0 views

synapse.koreamed.org/ViewImage.php

Cancer aerobic glycolysis warburg effect HIF-1alpha HIF-1

shared by Nathan Goodyear on 14 Dec 18 - No Cached
  • Nathan Goodyear on 14 Dec 18
     
    Nice image that clearly depicts aerobic glycolysis and more, the effects of HIF-1alpha due to hypoxia.
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

Mitochondria and Cancer - 0 views

www.ncbi.nlm.nih.gov/...PMC4779192

cancer mitochondria

shared by Nathan Goodyear on 05 Oct 18 - No Cached
  • aerobic glycolysis
  • aerobic glycolysis
  • the “Warburg effect” is the basis for tumor imaging by FDG-PET
  • ...1 more annotation...
  • In most cancers, oncogenic driver mutations such as activation of K-ras, c-Myc and phosphatidylinositol-3 (PI3) kinase or loss of phosphatase and tensin homolog (Pten) and p53, not mutations that inactivate mitochondrial respiration complexes, promote glycolysis
  • Nathan Goodyear on 05 Oct 18
     
    great read on mitochondria and cancer.
Nathan Goodyear

Imp2 controls oxidative phosphorylation and is crucial for preserving glioblastoma canc... - 0 views

www.ncbi.nlm.nih.gov/...PMC3435496

cancer glioblastoma glioblastoma multiforme "brain cancer" CSC cancer stem cells oxidative phosphorylation

shared by Nathan Goodyear on 28 Nov 18 - No Cached
  • Nathan Goodyear on 28 Nov 18
     
    Glioblastoma's CSCs found to rely on oxidative phosphorylation metabolism and not aerobic glycolysis.
Nathan Goodyear

How We Read Oncologic FDG PET/CT | Cancer Imaging | Full Text - 0 views

cancerimagingjournal.biomedcentral.com/...s40644-016-0091-3

PET_CT PET scan CT cancer

shared by Nathan Goodyear on 20 Feb 18 - No Cached
  • In early PET literature focusing on analysis of solitary pulmonary nodules, some researchers defined malignancy based on a SUVmax threshold of greater than 2.5
  • We contend that SUV analysis has virtually no role in this setting.
  • tumours grow as spheres, whereas inflammatory processes are typically linear
  • ...35 more annotations...
  • Far more important than the SUVmax is the pattern rather than intensity of metabolic abnormality and the correlative CT findings
  • Descriptively, we define SUV < 5 as “low intensity”, 5–10 as “moderate”, 10–15 as “intense” and >15 as “very intense”
  • Evolving literature suggests that intensity of uptake is an independent prognostic factor and in some tumour subtypes superior to histopathologic characterisation.
  • aerobic glycolysis
  • Our practice of thresholding the grey and colour scale to liver as detailed above results in similar image intensity to a fixed upper SUV threshold of 8 to 10
  • The advantage of using the liver as a reference tissue is also aided by this organ having rather low variability in metabolic activity
  • When the liver is abnormal and cannot be used as a reference organ, we use the default SUV setting of an upper SUV threshold of 8
  • One of the most challenging aspects of oncologic FDG PET/CT review, however, is to recognise all the patterns of metabolic activity that are not malignant and which consequently confound interpretation
  • Many benign and inflammatory processes are also associated with high glycolytic activity
  • Future articles in the “How I Read” series will address the specific details of reading PET/CT in various cancers
  • The intensity of uptake in metastases usually parallels that in the primary site of disease
  • For example, discordant low-grade activity in an enlarged lymph node in the setting of intense uptake in the primary tumour suggests it is unlikely malignant and more likely inflammatory or reactive
  • By CT criteria the enlarged node is ‘pathologic’ but the discordantly low metabolic signature further characterises this is as non-malignant since such a node is not subject to partial volume effects and therefore the intensity of uptake should be similar to the primary site
  • The exception is when the lymph node is centrally necrotic as a small rim of viable tumour is subject to partial volume effects with expectant lower intensity of uptake; integrating the CT morphology is therefore critical to reaching an accurate interpretation
  • Small nodes that are visualised on PET are conversely much more likely to be metastatic as such nodes are subject to partial volume effects.
  • The exception to this rule is tumours with a propensity for tumour heterogeneity at different sites
  • The combination of FDG and a more specific tracer, which visualises the well-differentiated disease can be very useful to characterise this phenomenon
  • “metabolic signature”
  • For the majority of malignant processes, the intensity of metabolic abnormality correlates with degree of aggressiveness or proliferative rate.
  • a negative PET/CT study in a patient with biopsy proven malignancy would be considered false-negative
  • Warburg effect
  • There, however, are a significant minority of tumours that utilise substrates other glucose such as glutamine or fatty acids as a source of the carbon atoms required for growth and proliferation
  • This includes a subset of diffuse gastric adenocarcinomas, signet cell colonic adenocarcinomas and some sarcomas, particularly liposarcoma
  • There may be a role for other radiotracers such as fluorothymidine (FLT) or amino acid substrates in this setting.
  • Some tumours harbour mutations that result in defective aerobic mitochondrial energy metabolism, effectively simulating the Warburg effect
  • patients with hereditary paraganglioma and pheochromocytoma highlight this phenomenon
  • These have intense uptake on FDG PET/CT despite often having low proliferative rate.
  • Uterine fibroids, hepatic adenomas, fibroadenomas of the breast and desmoid tumours are benign or relatively benign lesions that can have quite high FDG-avidity.
  • Metabolic activity switches off rapidly following initiation of therapy
  • Common examples where patients have commenced active therapy but the referrer is requesting “staging” includes hormonal therapy (eg. tamoxifen) in breast cancer, oral capecitabine in colorectal cancer or high dose steroids in Hodgkin’s lymphoma
  • It is therefore critical to perform PET staging before commencement of anti-tumour therapy
  • The potential advantage of routine diagnostic CT is improved anatomic localisation and definition
  • Without intravenous contrast, additional identification of typical oncologic complications such as pulmonary embolism or venous thrombosis cannot be identified
  • If the study is performed as an “interim” restaging study after commencement of therapy but before completion, in order to reach a valid or clinically useful conclusion findings must be interpreted in the context of known changes that occur at a specific timing and type of therapy
  • The most well studied use of interim PET is in Hodgkin’s lymphoma where repeat PET after two cycles of ABVD-chemotherapy provides powerful prognostic information and may improve outcomes by enabling early change of management
  • Nathan Goodyear on 20 Feb 18
     
    good read on the PET/CT scan reading.  They mention that tumors are spheres and inflammation is linear, yet inflammation coexists with cancer; hard to simply delineate these on simple terms. I do agree aon the metabolic signature of the PET/CT scan
Nathan Goodyear

Hypoxia-inducible Factor 1 Activation by Aerobic Glycolysis Implicates the Warburg Effe... - 0 views

www.jbc.org/...23111.long

HIF-1alpha cancer Hypoxia-inducible Factor 1

shared by Nathan Goodyear on 17 Oct 13 - No Cached
  • HIF-1 activation is highly associated with cancer cell growth and survival, tumor development, tumor angiogenesis, and poor clinical prognosis
  • The adaptation of cancer cells to hypoxia is mediated via hypoxia-inducible Factor 1 (HIF-1),1 a key transcription factor that up-regulates a series of genes involved in glycolytic energy metabolism, angiogenesis, cell survival, and erythropoiesis. Included among these genes are vascular endothelial growth factor (VEGF), erythropoietin (EPO), glucose transporters (GLUT), and several glycolytic enzymes (12, 13).
  • Nathan Goodyear on 17 Oct 13
     
    good discussion of HIF-1alpha and cancer
Nathan Goodyear

Role of Oxidative Stress and the Microenvironment in Breast Cancer Development and Prog... - 0 views

www.ncbi.nlm.nih.gov/...PMC3950899

cancer oxidative stress warburg effect reverse warburg effect ROS

shared by Nathan Goodyear on 11 Nov 14 - No Cached
  • oxidative stress leads to HIF-1α accumulation
  • Oxidative stress generated by breast cancer cells activates HIF-1α and NFκB in fibroblasts, leading to autophagy and lysosomal degradation of Cav-1
  • increased levels of hydrogen peroxide in exhaled breath condensate from patients with localized breast malignancy, associated with increased clinical severity
  • ...18 more annotations...
  • Comparing mitochondrial metabolic activity revealed a difference between stroma and epithelial cells
  • Overexpression of NOX4 in normal breast epithelial cells results in cellular senescence, resistance to apoptosis, and tumorigenic transformation, as well as increased aggressiveness of breast cancer cells
  • metalloproteinases (MMP) such as MMP-2, MMP-3, and MMP-9 increase extracellular matrix turnover and are themselves activated by oxidative stress
  • Lowered expression of Cav-1 not only leads to myofibroblast conversion and inflammation but also seems to impact aerobic glycolysis, leading to secretion of high energy metabolites such as pyruvate and lactate that drive mitochondrial oxidative phosphorylation in cancer cells
  • Reverse Warburg Effect
  • secreted transforming growth factor β (TGFβ), insulin-like growth factor (IGF), platelet-derived growth factor (PDGF), fibroblast growth factor 2, and stromal-derived factor 1 (SDF1) are able to activate fibroblasts and increase cancer cell proliferation
  • oxidative stress has an important role in the initiation and preservation of breast cancer progression
  • cancer preventive role of healthy mitochondria
  • the cancer cells produce hydrogen peroxide and by driving the “Reverse Warburg Effect” initiate oxidative stress in fibroblasts. As a result of this process, fibroblasts exhibited reduced mitochondrial activity, increased glucose uptake, ROS, and metabolite production.
  • Oxidative stress results from an imbalance between unstable reactive species lacking one or more unpaired electrons (superoxide anion, hydrogen peroxide, hydroxyl radical, reactive nitrogen species) and antioxidants
  • cancer cells are able to induce drivers of oxidative stress, autophagy and mitophagy: HIF-1α and NFκB in surrounding stroma fibro-blasts
  • Studies show that loss of Cav-1 in adjacent breast cancer stroma fibroblasts can be prevented by treatment with N-acetyl cysteine, quercetin, or metformin
  • However, diets rich in antioxidants have fallen short in sufficiently preventing cancer
  • hydrogen peroxide is one of the main factors that can push fibroblasts and cancer cells into senescence
  • It is widely held that HIF-1α function is dependent upon its location within the tumor microenvironment. It acts as a tumor promoter in CAFs and as a tumor suppressor in cancer cells
  • It was reported that overexpression of recombinant (SOD2) (Trimmer et al., 2011) or injection of SOD, catalase, or their pegylated counterparts can block recurrence and metastasis in mice
  • obstructing oxidative stress in the tumor microenvironment can lead to mitophagy and promote breast cancer shutdown is a promising discovery for the development of future therapeutic interventions.
  • Recent studies show that in the breast cancer microenvironment, oxidative stress causes mitochondrial dysfunction
  • Nathan Goodyear on 11 Nov 14
     
    Really fascinating article on tumor signaling. The article points to a complex signaling between cancer cells and stromal fibroblasts that results in myofibroblast transformation that increases the microenvironment favorability of cancer. This article points to oxidative stress as the primary driving force.  
Nathan Goodyear

BMC Cancer | Full text | A lactate shuttle system between tumour and stromal cells is a... - 0 views

www.biomedcentral.com/...352

cancer prostate cancer CAFs cancer associated fibroblasts mono-carboxylate transporters

shared by Nathan Goodyear on 12 Nov 14 - No Cached
  • Under hypoxic conditions, tumour cells primarily use glycolysis for energy, producing lactate, which is expelled to the tumour microenvironment, allowing tumours to continue their glycolytic activity
  • Sonveaux et al. showed that lactate, which is generally considered a waste product, is preferred over glucose by oxidative tumour cells as their primary energy source
  • MCT4 is a low-affinity transporter, which is abundant in highly glycolytic muscle cells and is one of the many target genes of hypoxia-inducible factor 1 alpha (HIF-1α)
  • ...8 more annotations...
  • Other targets of HIF-1α include glucose transporter-1 (GLUT-1), the main transporter involved in glucose uptake [9,10]; lactate dehydrogenase V (LDHV), which is responsible for the conversion of pyruvate into lactate; pyruvate dehydrogenase kinase isozyme 1 (PDK1), which is responsible for the phosphorylation and consequent inactivation of pyruvate dehydrogenase (PDH); and carbonic anhydrase IX (CAIX), a hypoxia-related protein involved in pH regulation [11]. Alpha-methylacyl-CoA racemase (AMACR), pristanoyl-CoA oxidase (ACOX-3) and D-bifunctional protein (DBP), are also important fatty acid oxidation-related proteins in prostate cancer
  • the essential role played by the cross-talk between stroma and epithelium in carcinogenesis and prostate cancer progression has been increasingly recognised
  • strong membranous expression of MCT1 was consistently observed in cancer cells, suggesting a role for MCT1 in the transport of lactate into tumour cells from the acidic extracellular matrix, suggesting that lactate might be used as a fuel by oxidative cancer cells.
  • Our hypothesis is in agreement with those of Fiaschi et al.[17], who describe the metabolic reprogramming of CAFs towards the Warburg phenotype as a result of contact with prostate cancer cells
  • Using in vitro studies, they showed lactate production and efflux by de novo expressed MCT4 in CAFs and also demonstrated that, upon contact with CAFs, prostate cancer cells were reprogrammed towards aerobic metabolism, with an increase in lactate uptake via the lactate transporter MCT1.
  • pharmacological inhibition of MCT1-mediated lactate uptake dramatically affected PCa cell survival and tumour outgrowth
  • In this model, “energy transfer” or “metabolic coupling” between the tumour stroma and epithelial cancer cells fuels tumour growth and metastasis via oxidative mitochondrial metabolism in anabolic cancer cells
  • the concomitant expression of MCT1 in tumour cells and MCT4 in fibroblasts in the same tissue is clinically significant, and associated with poor prognosis.
  • Nathan Goodyear on 12 Nov 14
     
    Study confirms the importance of the crosstalk between cancer cells and CAFs via MCTs in prostate cancer.
Nathan Goodyear

http://www.tandfonline.com/doi/pdf/10.4161/cc.8.23.10238 - 0 views

www.tandfonline.com/...cc.8.23.10238

reverse warburg effect war warburg effect cancer mono-carboxylate transporters CAFs fibroblasts

shared by Nathan Goodyear on 11 Nov 14 - No Cached
  • Nathan Goodyear on 11 Nov 14
     
    Good biochemical review of the Reverse Warburg Effect.  In pdf format, so I can't highlight.
Nathan Goodyear

Long-term stabilization of stage 4 colon cancer using sodium dichloroacetate therapy - 1 views

www.ncbi.nlm.nih.gov/...PMC5067498

DCA dichloroacetate dichloracetic acid cancer colon cancer

shared by Nathan Goodyear on 18 Jan 18 - No Cached
  • inhibition of mitochondrial pyruvate dehydrogenase kinase
  • inhibition of aerobic glycolysis (the Warburg effect) and activation of mitochondrial potassium ion channels
  • angiogenesis blockade
  • ...5 more annotations...
  • changes in expression of HIF1-α
  • alteration of pH regulators V-ATPase and MCT1, and other cell survival regulators such as PUMA, GLUT1, Bcl2 and p53
  • DCA as a cancer stabilizing agent
  • A protocol of natural medications was developed to address the dose-limiting neurologic toxicity, in collaboration with a naturopathic physician (Andrews). The oral DCA regimen that was developed included three natural medications acetyl L-carnitine[29-31], R-alpha lipoic acid[32-34] and benfotiamine[35-37], for the primary purpose of neuropathy prevention
  • measurable benefits from DCA therapy in 60%-70% of cases
  • Nathan Goodyear on 18 Jan 18
     
    Good review of dichloracetate or DCA in antitumor activity.  DCA has been shown to have numerous anticancer properties.
Nathan Goodyear

Acidic extracellular microenvironment and cancer - 0 views

www.ncbi.nlm.nih.gov/...PMC3849184

acid tumor cancer cancer lactate "lactic acid"

shared by Nathan Goodyear on 16 Nov 18 - No Cached
hoangkimchi liked it
  • Nathan Goodyear on 16 Nov 18
     
    Cancer thrives in an acidic micro environment, which also limits penetration of the immune system and other therapies often used in the treatment of cancer.
Nathan Goodyear

Hexokinase 2 is a key mediator of aerobic glycolysis and promotes tumor growth in human... - 0 views

jem.rupress.org/313

Hexokinase "hexokinase 2" "hexokinase II" glioblastoma cancer

shared by Nathan Goodyear on 19 Jan 19 - No Cached
  • Nathan Goodyear on 19 Jan 19
     
    to be read: hexokinase II and glioblastoma
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