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Nathan Goodyear

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

  • 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
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  • 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
       
      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
       
      And now the receipts
  • MMPs degrade ECM that facilitates angiogenesis, tumour cell invasion, and metastasis
    • Nathan Goodyear
       
      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
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    Important review article.
Nathan Goodyear

How is the Immune System Suppressed by Cancer - 1 views

  • nitric oxide (NO) released by tumor cells
  • Excellent work by Prof de Groot of Essen, indicated by adding exogenous xanthine oxidase ( XO) in hepatoma cells, hydrogen peroxide was produced to destroy the hepatoma cells
  • NO from eNOS in cancer cells can travel through membranes and over long distances in the body
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  • NO also is co linked to VEGF which in turn increases the antiapoptotic gene bcl-2
  • The other important influence of NO is in its inhibition of the proapoptoic caspases cascade. This in turn protects the cells from intracellular preprogrammed death.
  • nitric oxide in immune suppression in relation to oxygen radicals is its inhibitory effect on the binding of leukocytes (PMN) at the endothelial surface
  • Inhibition of inducible Nitric Oxide Synthase (iNOS)
  • NO from the tumor cells actually suppresses the iNOS, and in addition it reduces oxygen radicals to stop the formation of peroxynitrite in these cells. But NO is not the only inhibitor of iNOS in cancer.
  • Spermine and spermidine, from the rate limiting enzyme for DNA synthases, ODC, also inhibit iNOS
  • tolerance in the immune system that decreases the immune response to antigens on the tumors
  • Freund’s adjuvant
  • increase in kinases in these cells which phosphorylate serine, and tyrosine
  • responsible for activation of many growth factors and enzymes
  • phosphorylated amino acids suppress iNOS activity
  • Hexokinase II
  • Prostaglandin E2, released from tumor cells is also an inhibitor of iNOS, as well as suppressing the immune system
  • Th-1 subset of T-cells. These cells are responsible for anti-viral and anti-cancer activities, via their cytokine production including Interleukin-2, (IL-2), and Interleukin-12 which stimulates T-killer cell replication and further activation and release of tumor fighting cytokines.
    • Nathan Goodyear
       
      Th1 cells stimulate NK and other tumor fighting macrophages via IL-2 and IL-12; In contrast, Th2, which is stimulated in allergies and parasitic infections, produce IL-4 and IL-10.  IL-4 and IL-10 inhibit TH-1 activation and the histamine released from mast cell degranulation upregulates T suppressor cells to further immune suppression.
  • Th-2 subset of lymphocytes, on the other hand are activated in allergies and parasitic infections to release Interleukin-4 and Interleukin-10
  • These have respectively inhibitory effects on iNOS and lymphocyte Th-1 activation
  • Mast cells contain histamine which when released increases the T suppressor cells, to lower the immune system and also acts directly on many tumor Histamine receptors to stimulate tumor growth
  • Tumor cells release IL-10, and this is thought to be one of the important areas of Th-1 suppression in cancer patients
  • IL-10 is also increased in cancer causing viral diseases such as HIV, HBV, HCV, and EBV
  • IL-10 is also a central regulator of cyclooxygenase-2 expression and prostaglandin production in tumor cells stimulating their angiogenesis and NO production
  • nitric oxide in tumor cells even prevents the activation of caspases responsible for apoptosis
    • Nathan Goodyear
       
      NO produced by cancer cells inhibits proapoptotic pathways such as the caspases.
  • early stages of carcinogenesis, which we call tumor promotion, one needs a strong immune system, and fewer oxygen radicals to prevent mutations but still enough to destroy the tumor cells should they develop
  • later stages of cancer development, the oxygen radicals are decreased around the tumors and in the tumor cells themselves, and the entire cancer fighting Th-1 cell replication and movement are suppressed. The results are a decrease in direct toxicity and apoptosis, which is prevented by NO, a suppression of the macrophage and leukocyte toxicity and finally, a suppression of the T-cell induced tumor toxicity
  • cGMP is increased by NO
  • NO in cancer is its ability to increase platelet-tumor cell aggregates, which enhances metastases
  • the greater the malignancies and the greater the metastatic potential of these tumors
  • The greater the NO production in many types of tumors,
  • gynecological
  • elevated lactic acid which neutralizes the toxicity and activity of Lymphocyte immune response and mobility
  • The lactic acid is also feeding fungi around tumors and that leads to elevated histamine which increases T-suppressor cells.  Histamine alone stimulates many tumor cells.
    • Nathan Goodyear
       
      The warburg effect in cancer cells results in the increase in local lactic acid production which suppresses lymphocyte activity and toxicity as well as stimulates histamine production with further stimulates tumor cell growth.
  • T-regulatory cells (formerly,T suppressor cells) down regulate the activity of Natural killer cells
  • last but not least, the Lactic acid from tumor cells and acidic diets shifts the lymphocyte activity to reduce its efficacy against cancer cells and pathogens in addition to altering the bacteria of the intestinal tract.
  • intestinal tract bacteria in cancer cells release sterols that suppress the immune system and down regulate anticancer activity from lymphocytes.
  • In addition to the lactic acid, adenosine is also released from tumors. Through IL-10, adenosine and other molecules secreted by regulatory T cells, the CD8+ cells can be inactivated to an anergic state
  • Adenosine up regulates the PD1 receptor in T-1 Lymphocytes and inhibits their activity
  • Adenosine is a purine nucleoside found within the interstitial fluid of solid tumors at concentrations that are able to inhibit cell-mediated immune responses to tumor cells
  • Adenosine appears to up-regulate the PD1 receptor in T-1 Lymphocytes and inhibits the immune system further
  • Mast cells with their release of histamine lower the immune system and also stimulate tumor growth and activate the metalloproteinases involved in angiogenesis and metastases
  • COX 2 inhibitors or all trans-retinoic acid
  • Cimetidine, an antihistamine has been actually shown to increase in apoptosis in MDSC via a separate mechanism than the antihistamine effect
    • Nathan Goodyear
       
      cimetidine is an H2 blocker
  • interleukin-8 (IL-8), a chemokine related to invasion and angiogenesis
  • In vitro analyses revealed a striking induction of IL-8 expression in CAFs and LFs by tumor necrosis factor-alpha (TNF-alpha)
  • these data raise the possibility that the majority of CAFs in CLM originate from resident LFs. TNF-alpha-induced up-regulation of IL-8 via nuclear factor-kappaB in CAFs is an inflammatory pathway, potentially permissive for cancer invasion that may represent a novel therapeutic target
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    Great review of the immunosuppression in cancer driven by the likes of NO.
Nathan Goodyear

Role of IL-2 in cancer immunotherapy: OncoImmunology: Vol 5, No 6 - 1 views

  • IL-2 is one of the key cytokines with pleiotropic effects on the immune system
  • IL-2 as “T-cell growth factor”
  • approved for the treatment of metastatic renal cell carcinoma (1992) and later for metastatic melanoma (1998) by FDA
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  • It is produced predominately by antigen-simulated CD4+ T cells, while it can also be produced by CD8+ cells, natural killer (NK) cells, and activated dendritic cells (DC)
  • IL-2 is an important factor for the maintenance of CD4+ regulatory T cells
  • plays a critical role in the differentiation of CD4+ T cells into a variety of subsets
  • It can promote CD8+ T-cell and NK cell cytotoxicity activity, and modulate T-cell differentiation programs in response to antigen, promoting naive CD4+ T-cell differentiation into T helper-1 (Th1) and T helper-2 (Th2) cells while inhibiting T helper-17 (Th17) differentiation
  • Of note, Tregs, which act to dampen the immune response, constitutively express high levels of α chain
  • IL-2Rα is unique to IL-2 and is expressed by a number of immune cells including T regulatory cells (Treg), activated CD4+ and CD8+T cells, B cells, mature DCs, endothelial cells
  • some investigators evaluated the efficacy of regimens containing low-dose IL-2
  • IL-2 can promote the activation and cell growth of T and NK cells
  • Unfortunately, not all of patients would benefit from targeted therapy and nearly all patients who initially respond to targeted inhibitors inevitably develop acquired resistance to the treatment
  • IL-2 also stimulates T-regulatory cells that constitutively express CTLA-4 and can suppress immune reactions. Hence, IL-2 might enhance antitumor reactivity in the presence of CTLA-4 blockade
  • both HD and low-dose IL-2 therapy preferentially induce the expansion of CD4+CD25+Foxp3+ Treg and the Treg level remains elevated after each cycle of HD IL-2 therapy
  • Due to rapid elimination and metabolism via the kidney, IL-2 has a short serum half-life of several minutes
  • HD IL-2-induced severe toxicities including vascular leak syndrome (VLS), pulmonary edema, hypotension, and heart toxicities
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    Great historical and functional role of IL-2 in the fight against cancer.
Nathan Goodyear

Cutting Edge: IL-12 Induces CD4+CD25− T Cell Activation in the Presence of T ... - 0 views

  • Whereas IL-12 instigates Th1 immune responses, CD4+CD25+ regulatory T cells (Treg)3 actively restrain them
  • Following engagement of their TCR, Treg suppress the proliferation of conventional CD4+CD25− T responder cells in vitro
  • Furthermore, they inhibit the development of CD4+ T cell responses against alloantigens, tumor, microbial, and self-Ags in vivo.
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  • Treg act to prevent spontaneous autoimmunity and to limit collateral damage to healthy tissues during adaptive immunity. However, these cells also have the potential to sabotage protective antimicrobial responses
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    Great T cell activiation review: Il-2 stimulates NK cells primarily release from TH1 cells and T cytotoxic lymphocytes are under the control of IL-12 released primarily from dendritic cells.  Inflammatory cytokines in the presence of Treg to stimulate CD4+CD25- T cell activation.
Nathan Goodyear

The Complex Role of Estrogens in Inflammation - 0 views

  • These studies suggest inflammation-dependent up-regulation of ERβ relative to ERα.
  • up-regulation of ERβ relative to ERα under hypoxic conditions, which might lead to a preponderance of signaling through ERβ pathways
  • it seems that E2 at periovulatory to pregnancy levels inhibited proinflammatory cytokines from PBMCs
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  • it is clear that E2 can stimulate antibody production by B cells, probably by inhibiting T cell suppression of B cells
  • In cycling women, the largest quantities of Ig were detected before ovulation
  • In contrast, E2 at high concentrations leads to a suppression of B-lymphocyte lineage precursors
  • E2 at periovulatory to pregnancy serum levels is able to stimulate antibody secretion under healthy conditions but also in autoimmune diseases, whereas similar serum levels of E2 lead to a suppression of bone marrow B cell lineage precursors
  • In chronic inflammatory disorders, where B cells play a decisive role, E2 would promote the disease when autoaggressive B cells are already present, whereas chronically elevated E2 would inhibit initiation of an autoimmune disease when no such B cells are available. This might be a good reason why particularly B cell-dependent diseases such as SLE, mixed connective tissue disease (Sharp syndrome), IgA nephropathy, dermatitis herpetiformis, gluten sensitive enteropathy, myasthenia gravis, and thyroiditis appear in women in the reproductive years, predominantly, in the third or fourth decades of life
  • Th17 cells are thought to be the main responsible cells for chronic inflammatory tissue destruction in autoimmune diseases
  • IFN-γ, IL-12, and TNF were allocated to Th1 reactions
  • IL-4, IL-5, and IL-10 to Th2 responses
  • antiinflammatory T regulatory cells producing TGF-β and proinflammatory T helper type 17 cells (Th17) producing IL-17
  • no direct effects of estrogens on Th17 cells or IL-17 secretion have been described until now.
  • So-called Th17 cells producing IL-17 are the main T cells responsible for chronic inflammation.
  • Because IFN-γ has been allocated a Th17-inhibiting role (Fig. 1⇑), its increase by E2 at pregnancy doses and the E2-mediated inhibition of TNF must be viewed as a favorable effect in chronic inflammation
  • in humans and mice, E2 at periovulatory to pregnancy levels stimulates IL-4, IL-10, and IFN-γ but inhibits TNF from CD4+ T cells
  • In humans and mice, E3 and E2, respectively, at pregnancy levels inhibit T cell-dependent delayed type hypersensitivity
  • increased IL-4, IL-10, and IFN-γ in the presence of low TNF support an antiaggressive immune response
  • secretion of IL-1β is increased at periovulatory/proestrus to early pregnancy levels, whereas IL-1 secretion is inhibited at high pregnancy levels
  • The dichotomous effect of E2 on IL-1β and TNF at high and low concentrations is most probably due to inhibition of NF-κB at high concentrations
  • experiments with mouse and rat macroglial and microglial cells demonstrate that E2 at proestrus to pregnancy levels exerts neuroprotective effects by increasing TGF-β and by inhibiting iNOS and NO release, and reducing expression of proinflammatory cytokines and prostaglandin E2 production.
  • E2 at periovulatory to pregnancy levels inhibits NF-κB activation, which must be viewed as an antiinflammatory signal
  • It was shown that E2 concentrations equal to or above 10−10 m are necessary to inhibit NF-κB activation
  • important proinflammatory cytokines are typically inhibited at periovulatory (proestrus) to pregnancy levels of E2, which is evident for IL-6, IL-8, and TNF
  • low E2 concentrations were demonstrated to have no or even stimulatory effects
  • This renders a woman in the postmenopausal phase to a more proinflammatory situation
  • most in vitro studies demonstrated a stimulatory effect of E2 on secretion of IL-4, IL-10, and TGF-β typically at periovulatory to pregnancy levels
  • E2 at periovulatory to pregnancy levels has an ameliorating effect on chronic inflammatory diseases as long as B cell-dependent immunity or an overshooting fibrotic tissue repair process do not play a crucial pathogenic role. However, when the B cell plays an important role, E2 might even stimulate the disease process as substantiated by flare-ups in SLE during pregnancy
    • Nathan Goodyear
       
      SLE, mixed connective tissue disease (Sharp syndrome), IgA nephropathy, dermatitis herpetiformis, gluten sensitive enteropathy, myasthenia gravis, and thyroiditis
  • Short-term administration of E2 at pregnancy levels was shown to induce an inflammatory response specific to the lateral prostate of the castrated male rat
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    great review of the complex interaction between Estrogens and inflammation.  Reference here is in females.
Nathan Goodyear

Exposure to Bisphenol A Prenatally or in Adulthood Promotes TH2 Cytokine Production Ass... - 0 views

  • BPA promotes the development of TH2 cells in adulthood and both TH1 and TH2 cells in prenatal stages by reducing the number of regulatory T cells.
  • Bisphenol A (BPA), an estrogenic endocrine-disrupting chemical (EDC
  • BPA is one of the most widespread EDCs.
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  • BPA antagonizes the actions of thyroid hormone
  • Prenatal exposure to BPA has been shown to alter a variety of reproductive endocrine parameters, such as testosterone and luteinizing hormone levels
  • arly onset of sexual maturation of female mice
  • imbalanced T-helper (TH)1/TH2 immune responses have been demonstrated on exposure to BPA
  • indicating that BPA exerted its effects by reducing the number of Treg cells.
  • Exposure to BPA by subcutaneous injection in adulthood significantly promoted antigen-stimulated production of IL-4, IL-10, and IL-13 in TH2-skewed
  • BPA can leak from the placenta and accumulate in the fetus
  • We showed that prenatal exposure to BPA increased the production of a TH1 cytokine, IFN-γ, and a TH2 cytokine, IL-4, after the offspring developed, suggesting that prenatal exposure to BPA can induce persistent immunologic effects lasting into adulthood.
  • These results are consistent with a previous report that fetal exposure to BPA augmented TH1 and TH2 immune responses
  • our results clearly demonstrate that the production of TH2 cytokines is promoted by BPA in adult mice and in offspring during developmental exposure.
  • The decrease of Treg cells would predispose to immune dysfunction in aged individuals, explaining their higher risk of immune-mediated diseases, cancer, and infections.
  • BPA might cause these diseases. Thus, avoiding exposure to or promoting the excretion of BPA and other EDCs would help in preventing diseases and adverse health effects.
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    BPA as endocrine disruptor and as immune disruptor
Nathan Goodyear

How regulatory T cells work - 0 views

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    T reg  cells are the primary regulators of the immune system signaling.
Nathan Goodyear

Gender and sex hormones in multiple sclerosis pathology and therapy - 0 views

  • It is now well recognized that the disease manifestation is reduced in pregnant women with relapsing-remitting MS
  • This occurs particularly during the third trimester when levels of estrogens (estradiol and estriol) and progesterone (see Table 2) are elevated up to about 20 times
  • This seems well correlated with a decrease in active white matter lesions detected by MRI
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  • This clinical improvement is however followed by temporary rebound exacerbations at post-partum, when the hormone levels decline
  • a shift from Th1 to Th2 immune response, expansion of suppressive regulatory T lymphocytes and decrease in the number of circulating CD16+ natural killer (NK)-cells
  • Th1 lymphocytes secrete proinflammatory cytokines (e.g. IL-2, IFNgamma, lymphotoxin) while Th2 cells secrete anti-inflammatory cytokines (e.g. IL-4, IL-5, IL-10), which favor humoral-mediated responses
  • Th2 cytokines are associated with down-regulation of Th1 cytokines and this Th2 shift is believed to provide protection from allograft rejection during pregnancy as well as from Th1-mediated autoimmune disease
  • it is worth noting that the levels of other hormones with anti-inflammatory activity (1,25-dihydroxy-vitamin D3, norepinephrine, cortisol) also increase by 2 to 4 times during late pregnancy
  • 1,25-dihydroxy vitamin D3 induces regulatory T-cell function important for development of self-tolerance
  • breast-feeding does not alter the relapse rate in women with MS
  • Leptin is a pleiotropic hormone produced primarily by adipocytes but also by T lymphocytes and neurons
  • Several lines of evidence indicate that leptin contributes to EAE/MS pathogenesis, influencing its onset and clinical severity, by acting as a proinflammatory cytokine which promotes regulatory T cell (Treg) anergy and hyporesponsiveness, resulting in increased Th1 (TNFalpha, INFgamma) and reduced Th2 (IL-4) cytokine production
  • circulating leptin levels are increased in relapsing-remitting MS patients (men and women analyzed together) while the CD4+CD25+Treg population decreases
  • As the leptin plasma concentrations are proportional to the amount of fat tissue, obese/overweight individuals produce higher levels of leptin
  • Nielsen et al found that estradiol and progesterone exert neuroprotection against glutamate neurotoxicity, while MPA antagonizes the neuroprotective effect of estradiol and exacerbated neuron death induced by glutamate excitotoxicity
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    very good review of the differences in MS and hormones between the sexes.
Nathan Goodyear

Special regulatory T-cell review: suppressors regulated but unsuppressed - 0 views

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    T regulator cell review
Nathan Goodyear

The psychoneuroendocrine-immunotherapy of cancer: Historical evolution and clinical res... - 0 views

  • It is known that immune system-induced destruction of cancer cells is mainly mediated by T cytotoxic lymphocytes (CD8+) and NK cells (CD16+), respectively, through an antigen-specific and an antigen nonspecific cytotoxicity
  • NK cells are mainly stimulated by IL-2 released by T helper-1 (TH1) lymphocytes (CD4+) while T cytotoxic lymphocytes (CD8+) are namely under a stimulatory control released by IL-12 produced by the dendritic cells
  • On the other hand, the anticancer immunity is inhibited by the activation of the macrophage system through the production of suppressive cytokines, such as IL-6 and T regulatory (T reg) lymphocytes (CD4+CD25+), which counteract the anticancer immunity by producing immunosuppressive cytokines inhibiting the secretion of both IL-2 and IL-12, including TGF-beta and IL-10, or by a direct cell-cell contact
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    to be read review of melatonin in cancer treatment.
Nathan Goodyear

IMAJ | The Israel Medical Association Journal | Volume 12, Number 3, March 2010 | Vitam... - 0 views

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    Vitamin D's positive impact in autoimmune disease likely is through Treg cells.  This study found a statistically significant increase in Tregs with vitamin D therapy.
Nathan Goodyear

IL-2: The First Effective Immunotherapy for Human Cancer | The Journal of Immunology - 0 views

  • IL-2 is a 15.5-kDa cytokine secreted predominately by Ag-simulated CD4+ T cells, but it can also be produced by CD8+ cells, NK cells, and activated dendritic cells
  • IL-2 is the predominant factor responsible for the maintenance of CD4+ regulatory T cells
  • A generalized capillary leak syndrome was induced by IL-2 in vivo that resulted in interstitial pulmonary infiltrates and substantial weight gain in patients
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  • The side effects were transient and returned to baseline following treatment
  • Tumors do not express IL-2 receptors and thus the antitumor activity was the result of IL-2 stimulation of immune cell
  • Patients with metastatic melanoma or metastatic renal cell cancer were uniquely responsive to high-dose IL-2 administration, and except for patients with advanced non-Hodgkin’s lymphomas (35) only rare responses were seen in patients with other tumor types
  • The underlying toxicity of IL-2 results from a capillary leak that leads to fluid extravasation into visceral organs that can compromise their function
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    Great review of the history of IL-2 in the treatment of cancer.  IL-2 stimulates the immune system to attack cancer.  Don't reinvent the wheel; use what is already present and available.
Nathan Goodyear

Restoration of regulatory and effector T cell balance and B cell homeostasis in systemi... - 0 views

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    Vitamin D support provides benefit in those with Lupus.  The proposed mechanism is through the balance of Treg cells and Th17 cells.  This imbalance plays a role in the etiology of autoimmune disease and those with autoimmune disease, such as in Lupus, frequently have low vitamin D levels.
Nathan Goodyear

The imbalance between regulatory and IL-17-se... [Clin Rheumatol. 2010] - PubMed - NCBI - 0 views

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    Balance of T reg cells and Th17 cells plays a role in active versus inactive Lupus.
Nathan Goodyear

Regulatory effects of estriol on T cell migra... [J Neuroimmunol. 2002] - PubMed - NCBI - 0 views

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    Pregnancy is a immunosuppressive state.  Estriol therapy mimics that through decrease in T cell migration and activation.  Estriol moved the Tcells to a Th2 dominance and also was found to inhibit NF-kappaB.  Estriol decreased TNF-alpa through IL-10 production.
Nathan Goodyear

PLOS ONE: Microbial Dysbiosis in Colorectal Cancer (CRC) Patients - 0 views

  • differences in the colon microbiota in individuals with colon cancer versus those with a normal colonoscopy
  • qPCR revealed significant elevation of the Bacteroides/Prevotella population in cancer patients that appeared to be linked with elevated IL17 producing cells in the mucosa of individuals with cancer.
  • Bacteroides genus populations and more specifically those of Bacteroides fragilis, have recently been shown to produce a metalloprotease in colon cancer patients, but not in controls [12] suggesting this species sub population might favor carcinogenesis
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  • It is noteworthy that among the many mechanisms that may mediate associations between microbiota and human health [21]–[22], pro-inflammatory and immune cell activation in colon mucosa are of great importance in relation to malignancy
  • B. fragilis has been shown to induce mucosal regulatory T-cell responses in the intestine involving TH17 cell recruitment in experimental models
  • the elevations of Bacteroides in the stool and/or IL17 immunoreactive cells in the normal mucosa appear to be promising sensitive markers
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    A relationship between dysbiosis and colon cancer appears to be present.  Particularly an increase in Bacteroidetes and Prevotella species were found in those with colon cancer versus those without.  An inflammatory up regulation of IL-17 appears to be involved.  Whether this is a cause or effect is yet to be determined, but the presence of elevated Bacteroidetes species with increased IL17 could be used as sensitive biomarkers.
Nathan Goodyear

Arthritis Research & Therapy | Abstract | Restoration of regulatory and effector T cell... - 0 views

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    Vitamin D supplementation in those individuals with SLE found to benefit these patients.   Vitamin D found to reduce TH1 and Th17 activity.  It also was found to decrease memory B cells and auto-antibodies.  Also of note is the level of vitamin D after therapy-only at 51.4 at 2 months and 41.5 at 6 months.
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