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Nathan Goodyear

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

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

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

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

Testosterone and glucose metabolism in men: current concepts and controversies - 0 views

joe.endocrinology-journals.org/...R37.full

Low T Testosterone metabolic syndrome MetS Diabetes men male glucose hormone hormones g

shared by Nathan Goodyear on 04 Feb 14 - No Cached
  • Around 50% of ageing, obese men presenting to the diabetes clinic have lowered testosterone levels relative to reference ranges based on healthy young men
  • The absence of high-level evidence in this area is illustrated by the Endocrine Society testosterone therapy in men with androgen deficiency clinical practice guidelines (Bhasin et al. 2010), which are appropriate for, but not specific to men with metabolic disorders. All 32 recommendations made in these guidelines are based on either very low or low quality evidence.
  • A key concept relates to making a distinction between replacement and pharmacological testosterone therapy
  • ...59 more annotations...
  • The presence of symptoms was more closely linked to increasing age than to testosterone levels
  • Findings similar to type 2 diabetes were reported for men with the metabolic syndrome, which were associated with reductions in total testosterone of −2.2 nmol/l (95% CI −2.41 to 1.94) and in free testosterone
  • low testosterone is more predictive of the metabolic syndrome in lean men
  • Cross-sectional studies uniformly show that 30–50% of men with type 2 diabetes have lowered circulating testosterone levels, relative to references based on healthy young men
  • In a recent cross-sectional study of 240 middle-aged men (mean age 54 years) with either type 2 diabetes, type 1 diabetes or without diabetes (Ng Tang Fui et al. 2013b), increasing BMI and age were dominant drivers of low total and free testosterone respectively.
  • both diabetes and the metabolic syndrome are associated with a modest reduction in testosterone, in magnitude comparable with the effect of 10 years of ageing
  • In a cross-sectional study of 490 men with type 2 diabetes, there was a strong independent association of low testosterone with anaemia
  • In men, low testosterone is a marker of poor health, and may improve our ability to predict risk
    • Nathan Goodyear
      Nathan Goodyear on 04 Feb 14
       
      probably the most important point made in this article
  • low testosterone identifies men with an adverse metabolic phenotype
  • Diabetic men with low testosterone are significantly more likely to be obese or insulin resistant
  • increased inflammation, evidenced by higher CRP levels
  • Bioavailable but not free testosterone was independently predictive of mortality
  • It remains possible that low testosterone is a consequence of insulin resistance, or simply a biomarker, co-existing because of in-common risk factors.
  • In prospective studies, reviewed in detail elsewhere (Grossmann et al. 2010) the inverse association of low testosterone with metabolic syndrome or diabetes is less consistent for free testosterone compared with total testosterone
  • In a study from the Framingham cohort, SHBG but not testosterone was prospectively and independently associated with incident metabolic syndrome
  • low SHBG (Ding et al. 2009) but not testosterone (Haring et al. 2013) with an increased risk of future diabetes
  • In cross-sectional studies of men with (Grossmann et al. 2008) and without (Bonnet et al. 2013) diabetes, SHBG but not testosterone was inversely associated with worse glycaemic control
  • SHBG may have biological actions beyond serving as a carrier protein for and regulator of circulating sex steroids
  • In men with diabetes, free testosterone, if measured by gold standard equilibrium dialysis (Dhindsa et al. 2004), is reduced
    • Nathan Goodyear
      Nathan Goodyear on 04 Feb 14
       
      expensive, laborious process filled with variables
  • Low free testosterone remains inversely associated with insulin resistance, independent of SHBG (Grossmann et al. 2008). This suggests that the low testosterone–dysglycaemia association is not solely a consequence of low SHBG.
  • Experimental evidence reviewed below suggests that visceral adipose tissue is an important intermediate (rather than a confounder) in the inverse association of testosterone with insulin resistance and metabolic disorders.
  • testosterone promotes the commitment of pluripotent stem cells into the myogenic lineage and inhibits their differentiation into adipocytes
  • testosterone regulates the metabolic functions of mature adipocytes (Xu et al. 1991, Marin et al. 1995) and myocytes (Pitteloud et al. 2005) in ways that reduce insulin resistance.
  • Pre-clinical evidence (reviewed in Rao et al. (2013)) suggests that at the cellular level, testosterone may improve glucose metabolism by modulating the expression of the glucose-transported Glut4 and the insulin receptor, as well as by regulating key enzymes involved in glycolysis.
  • More recently testosterone has been shown to protect murine pancreatic β cells against glucotoxicity-induced apoptosis
  • Interestingly, a reciprocal feedback also appears to exist, given that not only chronic (Cameron et al. 1990, Allan 2013) but also, as shown more recently (Iranmanesh et al. 2012, Caronia et al. 2013), acute hyperglycaemia can lower testosterone levels.
  • There is also evidence that testosterone regulates insulin sensitivity directly and acutely
  • In men with prostate cancer commencing androgen deprivation therapy, both total as well as, although not in all studies (Smith 2004), visceral fat mass increases (Hamilton et al. 2011) within 3 months
  • More prolonged (>12 months) androgen deprivation therapy has been associated with increased risk of diabetes in several large observational registry studies
  • Testosterone has also been shown to reduce the concentration of pro-inflammatory cytokines in some, but not all studies, reviewed recently in Kelly & Jones (2013). It is not know whether this effect is independent of testosterone-induced changes in body composition.
  • the observations discussed in this section suggest that it is the decrease in testosterone that causes insulin resistance and diabetes. One important caveat remains: the strongest evidence that low testosterone is the cause rather than consequence of insulin resistance comes from men with prostate cancer (Grossmann & Zajac 2011a) or biochemical castration, and from mice lacking the androgen receptor.
  • Several large prospective studies have shown that weight gain or development of type 2 diabetes is major drivers of the age-related decline in testosterone levels
  • there is increasing evidence that healthy ageing by itself is generally not associated with marked reductions in testosterone
  • Circulating testosterone, on an average 30%, is lower in obese compared with lean men
  • increased visceral fat is an important component in the association of low testosterone and insulin resistance
  • The vast majority of men with metabolic disorders have functional gonadal axis suppression with modest reductions in testosterone levels
  • obesity is a dominant risk factor
  • men with Klinefelter syndrome have an increased risk of metabolic disorders. Interestingly, greater body fat mass is already present before puberty
  • Only 5% of men with type 2 diabetes have elevated LH levels
  • inhibition of the gonadal axis predominantly takes place in the hypothalamus, especially with more severe obesity
  • Metabolic factors, such as leptin, insulin (via deficiency or resistance) and ghrelin are believed to act at the ventromedial and arcuate nuclei of the hypothalamus to inhibit gonadotropin-releasing hormone (GNRH) secretion from GNRH neurons situated in the preoptic area
  • kisspeptin has emerged as one of the most potent secretagogues of GNRH release
  • hypothesis that obesity-mediated inhibition of kisspeptin signalling contributes to the suppression of the HPT axis, infusion of a bioactive kisspeptin fragment has been recently shown to robustly increase LH pulsatility, LH levels and circulating testosterone in hypotestosteronaemic men with type 2 diabetes
  • A smaller study with a similar experimental design found that acute testosterone withdrawal reduced insulin sensitivity independent of body weight, whereas oestradiol withdrawal had no effects
  • suppression of the diabesity-associated HPT axis is functional, and may hence be reversible
  • Obesity and dysglycaemia and associated comorbidities such as obstructive sleep apnoea (Hoyos et al. 2012b) are important contributors to the suppression of the HPT axis
  • weight gain and development of diabetes accelerate the age-related decline in testosterone
  • Modifiable risk factors such as obesity and co-morbidities are more strongly associated with a decline in circulating testosterone levels than age alone
  • 55% of symptomatic androgen deficiency reverted to a normal testosterone or an asymptomatic state after 8-year follow-up, suggesting that androgen deficiency is not a stable state
  • Weight loss can reactivate the hypothalamic–pituitary–testicular axis
  • Leptin treatment resolves hypogonadism in leptin-deficient men
  • The hypothalamic–pituitary–testicular axis remains responsive to treatment with aromatase inhibitors or selective oestrogen receptor modulators in obese men
  • Kisspeptin treatment increases LH secretion, pulse frequency and circulating testosterone levels in hypotestosteronaemic men with type 2 diabetes
  • change in BMI was associated with the change in testosterone (Corona et al. 2013a,b).
  • weight loss can lead to genuine reactivation of the gonadal axis by reversal of obesity-associated hypothalamic suppression
  • There is pre-clinical and observational evidence that chronic hyperglycaemia can inhibit the HPT axis
  • in men who improved their glycaemic control over time, testosterone levels increased. By contrast, in those men in whom glycaemic control worsened, testosterone decreased
  • testosterone levels should be measured after successful weight loss to identify men with an insufficient rise in their testosterone levels. Such men may have HPT axis pathology unrelated to their obesity, which will require appropriate evaluation and management.
  • Nathan Goodyear on 04 Feb 14
     
    Article discusses the expanding evidence of low T and Metabolic syndrome.
Nathan Goodyear

PLOS ONE: Increased Risk of Non-Fatal Myocardial Infarction Following Testosterone Ther... - 0 views

www.plosone.org/...10.1371%2Fjournal.pone.0085805

Testosterone therapy cardiovascular disease men male hormones

shared by Nathan Goodyear on 30 Jan 14 - No Cached
  • For all TT prescription subjects combined, the post/pre prescription rate ratio for MI (RR)was 1.36
  • In men aged 65 years and older the RR was 2.19 (1.27, 3.77), while in men under age 65 years the RR was 1.17
  • increasing RR with increasing age.
  • ...20 more annotations...
  • The RRs were 0.95 (0.54, 1.67) under 55 years
  • 1.35 (0.77, 2.38) at 55–59
  • 1.29 (0.71, 2.35) at 60–64,
  • 1.35 (0.44, 4.18) at 65–69, 1.62
  • 3.43 (1.54, 7.66) at 75 years and older
  • The adjusted post/pre RR for PDE5I across all ages was 1.08
  • For TT prescription, in men under age 65 years, the RR was 2.90 (1.49, 5.62) for those with a history of heart disease and 0.90 (0.61, 1.34) for those without
  • In men aged 65 year and older, the RR was 2.16 (0.92, 5.10) for those with a history of heart disease and 2.21 (1.09, 4.45) for those without.
  • Among men aged 65 years and older, we observed a two-fold increase in the risk of MI in the 90 days after filling an initial TT prescription
  • Among younger men with a history of heart disease, we observed a two to three-fold increased risk of MI in the 90 days following an initial TT prescription and no excess risk in younger men without such a history
  • Among older men, the two-fold increased risk was associated with TT prescription regardless of cardiovascular disease history
  • our own findings appear consistent with a higher frequency of thrombotic events following TT prescription among men with more extensive coronary vascular disease.
  • Our findings are consistent with a recent meta-analysis of placebo-controlled randomized trials of testosterone therapy lasting 12 or more weeks among mainly older men, which reported that testosterone therapy increased the risk of adverse cardiovascular-related events (OR = 1.54, 95%CI:1.09, 2.18), as well as serious adverse cardiovascular-related events (OR = 1.61, 95%CI:1.01, 2.56) which included myocardial infarction along with other conditions
  • This association appeared unrelated to average baseline testosterone level (p = 0.70) but varied by source of funding (p = 0.03), with a stronger summary effect in a meta-analysis of studies not funded by the pharmaceutical industry (OR = 2.06, 95%CI:1.34, 3.17) compared with studies funded by the pharmaceutical industry
    • Nathan Goodyear
      Nathan Goodyear on 30 Jan 14
       
      This supports prior analysis that studies done by pharmaceutical corps will be more favorable to their product(s) than those independently funded.  This is called bias.
  • the evidence supports an association between testosterone therapy and risk of serious, adverse cardiovascular-related events–including non-fatal myocardial infarction–in men
  • there is some evidence that low endogenous testosterone levels may also be positively associated with cardiovascular events
  • effects of endogenous and exogenous testosterone may differ. Exogenous testosterone (TT) is associated with physiologic changes that predispose to clotting and thrombotic disorders including increased blood pressure [18], polycythemia [19], reductions in HDL cholesterol [18], [20], and hyperviscosity of the blood and platelet aggregation. [20]–[23]; TT also increases circulating estrogens [24], [25] which may play a role in the observed excess of adverse cardiovascular-related events, given that estrogen therapy has been associated with this excess in both men and women
  • did not include information on the serologic or diagnostic indications for treatment.
  • no association between PDE5I prescriptions and the risk of MI
  • Recently TT has been increasing extraordinarily rapidly, including among younger men and among those without hormone measurement
  • Nathan Goodyear on 30 Jan 14
     
    New cohort study finds increased risk of Testosterone in men > 65 and those : these are based in marketing-based medicine not evidence based medicine.
Nathan Goodyear

Availability of evidence of benefits on overall survival and quality of life of cancer ... - 0 views

www.bmj.com/bmj.j4530

cancer cancer treatment survival quality of life

shared by Nathan Goodyear on 20 Dec 17 - No Cached
  • Although the goal of cancer treatment is to improve the quantity and quality of life,123 clinical trials designed to gain regulatory approval for new drugs often evaluate indirect or “surrogate” measures of drug efficacy. These endpoints show that an agent has biological activity, but they are not reliable surrogates for improved survival4567891011 or quality of life46111213
  • two recent systematic reviews suggest that the strength of association between surrogates in cancer clinical trials and life extension is generally low
  • Available data from the US show that only a small proportion of cancer treatments approved by the US Food and Drug Administration (FDA) unequivocally show benefits on survival or quality of life.30
  • ...16 more annotations...
  • We sought to systematically evaluate the evidence base for all new drugs and new indications for the treatment of solid tumours and haematological malignancies approved by the EMA in the five year period 2009-13
  • Three investigators (AP, EP, and EG) independently extracted data on and descriptively analysed the following trial features: characteristics of the participant population, study design (randomisation, crossover from experimental to control group, and blinding of investigators and participants), experimental and control groups, enrolment, primary and secondary endpoints, magnitude of benefit on survival and quality of life, and narrative interpretation of the findings
  • Only 18 of the 68 (26%) were supported by a pivotal study powered to evaluate overall survival as the primary outcome
  • From 2009 to 2013, the EMA approved use of 48 oncology drugs
  • Seventeen drugs were approved for treatment of haematological malignancies and 51 for treatment of solid tumours
  • Overall, 72 clinical trials supported the approval of 68 novel drug uses
  • Our scoring was limited to drugs for solid tumours
  • Among 68 cancer drug indications approved by the EMA in the period 2009-13, and with a median of 5.4 years’ follow-up, only 35 (51%) were associated with a significant improvement in survival (26/35) or quality of life (9/35) over existing treatment options, placebo, or as add on treatment
  • Only two of the 26 drugs shown to extend life also showed benefits on quality of life
  • 33 (49%) had not shown any improvement on survival or quality of life
  • This systematic evaluation of oncology drug approvals by the EMA in 2009-13 shows that most of the drugs (39/68, 57%) entered the market without evidence of improved survival or quality of life
  • At a minimum 3.3 years after market entry, there was still no conclusive evidence that 33 of these 39 cancer drugs either extended or improved life
  • What are potential reasons for the paucity of drug approvals with demonstrable survival advantages over existing treatments?
  • Firstly, only 18 (26%) indications for use in our cohort were supported by trials in which extension of life was the primary outcome
  • None of the pivotal studies supporting oncology drug approvals from 2009 to 2013 included quality of life as a primary outcome measure
  • Most new oncology drugs authorised by the EMA in 2009-13 came onto the market without clear evidence that they improved the quality or quantity of patients’ lives
  • Nathan Goodyear on 20 Dec 17
     
    New study from European Medicines Agency questions alot of the new cancer drugs brought to the market 2009-2013.  57% of the new drugs (39/68) were brought to the market without evidence of improved survival or quality of life.
Nathan Goodyear

Testosterone and Estradiol Regulate Free Insulin-Like Growth Factor I (IGF-I), IGF Bind... - 0 views

jcem.endojournals.org/...2941.full

IGF-1 testosterone Estradiol growth hormone hormones HGH GH IGFBP-1

shared by Nathan Goodyear on 12 Nov 12 - No Cached
  • Nathan Goodyear on 12 Nov 12
     
    testosterone and Estradiol effect IGF-1 levels.  This small study looked at 8 men and 8 postmenopausal women.  Findings:  low testosterone and high estradiol decrease IGF-1 availability.   Estradiol in postmenopausal women will result in a decrease in IGF-1 through an elevation of IGFBP-1.  In men, testosterone replacement stimulates increased HGH secretion and resultant IGF-1 secretion
Nathan Goodyear

Reevaluation of the protein requirement in young men with the indicator amino acid oxid... - 0 views

ajcn.nutrition.org/...995.long

protein macronutrients nutrition diet men

shared by Nathan Goodyear on 21 Jul 15 - No Cached
  • the mean and population-safe protein requirements were estimated to be 0.93 and 1.2 g · kg−1 · d
  • diet containing 0.90 g · kg−1 · d−1 was at or above physiologic protein requirements for sedentary men
  • The current EAR recommendation and RDA for protein are 0.66 and 0.80 g · kg−1 · d−1, respectively. We believe that these recommendations are tentative because no long-term studies have suggested that these values would maintain nitrogen balance along with lean body mass, muscle mass, serum protein concentrations, immunity, functional capacity etc
  • ...2 more annotations...
  • a series of long-term balance studies (67-69) showed that intake of the proposed safe allowance of 0.57 g (70) egg protein resulted in negative nitrogen balance, loss of lean body mass, and deteriorating serum protein and transferase values unless additional energy or nonessential nitrogen was supplied
  • The results of the present study suggest that the current EAR recommendations (0.66 g · kg−1 · d−1) and RDA (0.80 g · kg−1 · d−1) for protein are underestimated at 29% and 33%, respectively
  • Nathan Goodyear on 21 Jul 15
     
    study looked at protein requirements in 8 "healthy" men.  This study pointed to 1.2 g/kg/day as an appropriate daily dietary protein intake for healthy men.  This far exceeds levels per RDA.
Nathan Goodyear

In vivo loss-of-function screens identify KPNB1 as a new druggable oncogene in epitheli... - 0 views

www.pnas.org/E7301

Ivermectin cancer ovarian cancer oncogene oncogenes

shared by Nathan Goodyear on 20 Mar 18 - No Cached
  • we functionally validated a potent EOC oncogene, KPNB1, and showed its clinical relevance to human EOC
  • a well-established antiparasitic drug, ivermectin, has antitumor effects on EOC through its inhibition of KPNB1
  • EOC has high intertumor and intratumor heterogeneity at the molecular and epigenetic levels
  • ...22 more annotations...
  • the mortality rate of EOC has not been significantly changed for several decades
  • Sequencing revealed that almost all tumors (96%) had mutations in TP53, which serves as a major driver of this cancer
  • Low-prevalence but statistically significant mutations in nine other genes including NF1, BRCA1, BRCA2, RB1, and CDK12 were also identified, but the majority of genes were mutated at low frequency, making it difficult to distinguish between driver and passenger mutations
  • KPNB1 inhibition via any of three KPNB1 siRNAs or importazole treatment induced apoptosis in human EOC cell lines (Fig. 3 A–F and Fig. S4), and was accompanied by an increase in the expression levels of the proapoptotic proteins BAX and cleaved caspase-3
  • Stable overexpression of KPNB1 in SKOV3 and OVCAR3 (Fig. S6) significantly accelerated cell proliferation/survival (Fig. 5 A–C), confirming that KPNB1 functions as an oncogene in EOC
  • KPNB1 overexpression significantly decreased caspase-3/7 activity (Fig. 5D), in addition to the expression levels of cleaved caspase-3 and BAX proteins (Fig. 5E). KPNB1 overexpression also decreased p21 and p27 protein levels (Fig. 5E), as opposed to their increase by KPNB1 inhibition
  • KPNB1 functions as an antiapoptotic and proproliferative oncogene in EOC.
  • Patients with higher expression levels of KPNB1 showed earlier recurrence and worse prognosis than those with lower expression levels of KPNB1
  • KPNB1 acts as an oncogene in human EOC and represents a promising therapeutic target.
  • ivermectin treatment suppressed cell proliferation/viability in a dose-dependent manner (Fig. 7A), indicating that it exerts an antitumor effect on EOC
  • ivermectin also induced apoptosis
  • ivermectin increased the expression levels of BAX, and cleaved PARP, as well as p21 and p27
  • KPNB1 inhibition is responsible for the antitumor effect of ivermectin
  • we found that ivermectin synergistically reduced cell proliferation/viability in combination with paclitaxel in human EOC cells
  • Single treatment of ivermectin or paclitaxel reduced tumor growth in nude mice, but, notably, combination treatment of ivermectin and paclitaxel almost completely suppressed tumor growth
  • ERBB2, is amplified and overexpressed in many cancers, including breast (31), ovary (31), colon (32), bladder (33), non-small-cell lung (34), and gastric cancer (35), and is a poor prognostic factor in certain cancer types
  • KPNB1 was the second-highest-ranked gene identified in our screen
  • Increased KPNB1 protein levels have been reported in several cancers, including cervical cancer (42), hepatocellular carcinoma (43), and glioma (44), suggesting KPNB1’s oncogenic potential in these tumor types
  • our findings suggest that KPNB1 might serve as a master regulator of cell cycle by regulating several cell cycle-related proteins, including p21, p27, and APC/C family members
  • higher and/or more-frequent doses of ivermectin than currently approved for humans are well tolerated in humans
  • none of the mice in this study treated with the effective dosage of ivermectin for in vivo anticancer therapy showed severe adverse event
  • we found that the combination of ivermectin and paclitaxel produces a stronger antitumor effect on EOC cell lines than either drug alone
  • Nathan Goodyear on 20 Mar 18
     
    Ivermectin found to be pro-apoptotic for the epithelial ovarian cancer oncogene, KPNB1 in in Vivo study.  This effective anti-parasitic drug inhibits the KPNB1 oncogene.
Nathan Goodyear

Testosterone deficiency syndrome and cardiovascular health: An assessment of beliefs, k... - 0 views

www.ncbi.nlm.nih.gov/...PMC3929476

low T Testosterone cardiovascular disease physicians men male hormone hormones

shared by Nathan Goodyear on 03 Mar 14 - No Cached
  • The vast majority (88%) did not screen cardiac patients for TDS.
  • Testosterone deficiency has a prevalence of 7% in the general population, rising to 20% in elderly males
  • Males with CAD have lower testosterone levels than those with normal coronary angiograms of the same age,5 suggesting that the prevalence of testosterone deficiency is much higher in the CAD population
  • ...14 more annotations...
  • Men with hypertension, another established risk factor for CAD, have lower testosterone compared to normotensive men
  • Recent meta-analyses showed that testosterone levels are generally lower among patients with metabolic syndrome, regardless of the various definitions of metabolic syndrome that are used
  • Testosterone (total and bioavailable) and sex-hormone binding globulin (SHBG) are inversely associated with the prevalence of metabolic syndrome in men between the ages of 40 and 80, and this association persists across racial and ethnic backgrounds
  • ower levels of testosterone and SHBG predict a higher incidence of metabolic syndrome.
  • Low testosterone levels have been related to increased insulin resistance and cardiovascular mortality,12 even in the absence of overt type 2 diabetes mellitus.
  • testosterone levels (total and bioavailable) in middle-aged men are inversely correlated with insulin resistance
  • The Massachusetts Male Aging Study (MMAS) demonstrated that low levels of testosterone and SHBG are independent risk factors for the development of type 2 diabetes,
  • Andropausal men (age 58 ± 7 years) have a higher maximal carotid artery intima-media thickness
  • There is an inverse linear correlation between body mass index (BMI) and wait-to-hip ratio with testosterone and insulin-like growth factor-1 levels.
  • Testosterone supplementation for 1 year in hypogonadal men has been shown to cause a significant improvement in body weight, BMI, waist size, lipid profile, and C-reactive protein levels
  • TRT for 3 months in hypogonadal men with type 2 diabetes significantly improved fasting insulin sensitivity, fasting blood glucose and glycated hemoglobin.
  • Testosterone replacement can improve angina symptoms and delay the onset of cardiac ischemia, likely through a coronary vasodilator mechanism
  • ADT is associated with an increased risk of cardiovascular events, including myocardial infarction and cardiovascular mortality.
  • ADT significantly increases fat mass, decreases lean body mass,29,30 increases fasting plasma insulin and decreases insulin sensitivity31 and increases serum cholesterol and triglyceride levels
  • Nathan Goodyear on 03 Mar 14
     
    Startling study on the knowledge of Testosterone and cardiovascular disease in general practitioners and cardiologists in Canada.  Eight-eight percent did not screen patients with cardiovascular disease for low Testosterone.  A whopping 67% of physicians did not know that low T was a risk factor for cardiovascular disease, yet 62% believed Testosterone would increase exercise tolerance. The lack of knowledge displayed by physicians today is staggering and is an indictment of the governing bodies.  This was a survey conducted in Canada so there are obvious limitations to the strength/conclusion of this study.
Nathan Goodyear

Natural Killer Cells in Pregnancy and Recurrent Pregnancy Loss: Endocrine and Immunolog... - 0 views

edrv.endojournals.org/...44.full

natural killer cells pregnancy loss recurrent immune system miscarriage NK

shared by Nathan Goodyear on 15 Apr 12 - No Cached
  • NK cells have been the cells most extensively studied, primarily because they constitute the predominant leukocyte population present in the endometrium at the time of implantation and in early pregnancy
  • parental chromosomal abnormalities, uterine anatomic anomalies, endometrial infections, endocrine etiologies (luteal phase defect, thyroid dysfunction, uncontrolled diabetes mellitus), antiphospholipid syndrome, inherited thrombophilias, and alloimmune causes
  • estrogen
  • ...28 more annotations...
  • progesterone
  • prolactin
  • In summary, in vivo animal experiments have shown an inhibitory role of estrogen on peripheral NK cell lytic activity, which is partly due to suppression of NK cell output by the bone marrow and partly due to suppression of individual NK cell cytotoxicity. However, in vitro studies so far have failed to show conclusively a direct effect of estrogen on NK cells.
  • At the progesterone concentrations believed to be present in the uterus [up to 10−5 m at the maternal-fetal interface (35)], studies consistently show inhibition of lymphocyte proliferation (33) and inhibition of NK cytolytic activity in vitro
  • The exact role of prolactin in NK cell regulation is unknown.
  • The overall effects of estrogen on NK cells are likely multifactorial, therefore, and depend on the type of cell affected as well as the kind of ER expressed by that cell.
  • It is known that progesterone can directly affect T cell differentiation in vitro, suppressing development of the Th1 pathway and enhancing differentiation along the Th2 pathway (44)
  • Th1 cells predominantly produce interferon-γ (IFN-γ), IL-2, and TNF-β and are involved in cell-mediated immunity. Th2 cells produce IL-4, IL-5, IL-6, IL-10, and IL-13 and stimulate humoral immunity
  • Furthermore, in response to progesterone, γδ T cells produce progesterone-induced blocking factor (PIBF) (54
  • A defining characteristic of NK cells is their ability to lyse target cells without prior sensitization and without restriction by HLA antigens.
  • NK cell function is mainly regulated by IL-2 and IFN-γ
  • IL-2 causes both NK cell proliferation and enhanced cytotoxicity. IFN-γ augments NK cytolytic activity, but does not cause NK proliferation. The two cytokines act synergistically to augment NK cytotoxicity (6).
  • The largest leukocyte population in the endometrium consists of NK cells named large granulated lymphocytes
  • there is a significant increase in the number of uNK cells throughout the secretory phase, which peaks in early pregnancy when uNK cells comprise about 75% of uterine leukocytes (62)
  • Second, uNK cell phenotype changes during the normal menstrual cycle and early pregnancy (68)
  • general proinflammatory effect of estrogen, causing an influx of macrophages and neutrophils, which is antagonized by progesterone through its receptor (70, 71).
  • The mechanism of such a progesterone-induced local immunosuppression is unclear.
  • progesterone plays an important role in proliferation and differentiation of uNK cells (32).
  • Through promotion of a uterine Th2 environment, progesterone could indirectly affect uNK cell function
  • The mechanism of this increase in uNK cell numbers has been addressed in both human and mouse models, and is likely the result of: 1) recruitment of peripheral NK cells to the uterus, and 2) proliferation of existing uNK cells
  • prolactin system plays an important role in implantation and the maintenance of pregnancy
  • the exact pathways of hormonal regulation of NK cells remain to be delineated.
  • The exact function of uNK cells has not yet been unequivocally determined
  • uNK cells express a different cytokine profile, compared with resting peripheral NK cells. mRNAs for granulocyte CSF, M-CSF, GM-CSF, TNF-α, IFN-γ, TGF-β, and leukemia inhibitory factor (LIF) have been found in decidual CD56+ cells
  • Their increased numbers in early pregnancy, their hormonal dependence, and their close proximity to the infiltrating trophoblast all suggest that they play an important role in the regulation of the maternal immune response to the fetal allograft and the control of trophoblast growth and invasion during human pregnancy
  • role of uNK cell-derived cytokines on trophoblast growth and differentiation (114, 115, 116, 117).
  • Th1 immunity to trophoblast is associated with RPL, whereas Th2 immunity is associated with a successful pregnancy
  • RPL is associated with Th1 immunity, for which NK cells are partly responsible.
  • Nathan Goodyear on 15 Apr 12
     
    dysregulated immune system plays role in recurrent miscarriage.  Specifically, this article discusses natural killer cells (NK).
Nathan Goodyear

Effect of resistance exercise on muscle steroidogenesis | Journal of Applied Physiology - 0 views

jap.physiology.org/...1754

resistance resistance training training exercise Testosterone male female hormone hormones muscle

shared by Nathan Goodyear on 03 Sep 14 - No Cached
  • skeletal muscle cell cultures incubated with DHEA produced testosterone in a DHEA dose-dependent manner
  • Muscle joins a growing list of tissues found to be capable of steroidogenesis
  • testosterone appears to have a role in the maintenance of muscle mass in women, although the importance of this role has not yet been fully established.
  • ...7 more annotations...
  • Circulating testosterone concentrations are generally elevated following a bout of resistance exercise in men (24, 31, 46, 52), whereas findings for the effect of resistance exercise on circulating testosterone in women are equivocal, with increases (10, 42) and no changes observed (22, 31)
  • swimming (51) and treadmill running (2) can significantly increase muscle testosterone concentrations in male and female rats
  • This upregulation of muscle testosterone in rats appears, at least in part, to be due to an increase in 3β-HSD and 17β-HSD type 1 expression
  • The primary finding in this study was that muscle steroidogenesis (i.e., testosterone production) in highly resistance-trained humans was not affected by an acute bout of heavy resistance exercise
  • A secondary finding was that the apparent molecular mass of 17β-HSD type 3 was increased following a single bout of heavy resistance exercise.
  • No differences were found for muscle testosterone or steroidogenic enzyme (17β-HSD type 3 and 3β-HSD types 1 and 2) concentrations between sexes or in response to resistance exercise
  • In conclusion, heavy resistance exercise did not induce changes in muscle steroidogenesis as measured by muscle concentrations of testosterone, 3β-HSD types 1 and 2, and 17β-HSD type 3 in highly resistance-trained young men and women.
  • Nathan Goodyear on 03 Sep 14
     
    Resistance exercise did not increase muscle concentrations of Testosterone in men or women.  The individuals in this study were actively training.  These were not sedentary individuals.
Nathan Goodyear

Anticancer mechanisms of cannabinoids - 0 views

www.ncbi.nlm.nih.gov/...PMC4791144

THC cannabinoids cancer

shared by Nathan Goodyear on 18 Sep 18 - No Cached
  • modulating key cell signalling pathways involved in the control of cancer cell proliferation and survival
  • cannabinoids inhibit angiogenesis and decrease metastasis in various tumour types in laboratory animals
  • Cannabis sativa L. (marijuana)
  • ...41 more annotations...
  • of the approximately 108 cannabinoids produced by C. sativa, Δ9-tetrahydrocannabinol (thc) is the most relevant because of its high potency and abundance in plant preparations
  • Tetrahydrocannabinol exerts a wide variety of biologic effects by mimicking endogenous substances—the endocannabinoids anandamide3 and 2-arachidonoylglycerol4,5—that engage specific cell-surface cannabinoid receptors
  • the cb2 receptor was initially described to be present in the immune system6, but was more recently shown to also be expressed in cells from other origins
  • transient receptor potential cation channel subfamily V, member 1
  • orphan G protein–coupled receptor 55
  • Most of the effects produced by cannabinoids in the nervous system and in non-neural tissues rely on cb1 receptor activation
  • two major cannabinoid-specific receptors—cb1 and cb2
  • cardiovascular tone, energy metabolism, immunity, and reproduction
  • cannabinoids are well known to exert palliative effects in cancer patients
  • best-established use is the inhibition of chemotherapy-induced nausea and vomiting
  • thc and other cannabinoids exhibit antitumour effects in a wide array of animal models of cancer
  • cannabinoid receptors and their endogenous ligands are both generally upregulated in tumour tissue compared with non-tumour tissue
  • cb2 promotes her2 (human epidermal growth factor receptor 2) pro-oncogenic signalling in breast cancer
  • pharmacologic activation of cannabinoid receptors decreases tumour growth
  • endocannabinoid signalling can also have a tumour-suppressive role
  • pharmacologic stimulation of cb receptors is, in most cases, antitumourigenic. Nonetheless, a few reports have proposed a tumour-promoting effect of cannabinoids
  • most prevalent effect is the induction of cancer cell death by apoptosis and the inhibition of cancer cell proliferation
  • impair tumour angiogenesis and block invasion and metastasis
  • thc and other cannabinoids induce the apoptotic death of glioma cells by cb1- and cb2-dependent stimulation
  • Autophagy is primarily a cytoprotective mechanism, although its activation can also lead to cell death
  • autophagy is important for cannabinoid antineoplastic activity
  • autophagy is upstream of apoptosis in the mechanism of cannabinoid-induced cell death
  • the effect of cannabinoids in hormone- dependent tumours might rely, at least in part, on the ability to interfere with the activation of growth factor receptors
  • glioma cells), pharmacologic blockade of either cb1 or cb2 prevents cannabinoid-induced cell death with similar efficacy
  • other types of cancer cells (pancreatic48, breast24, or hepatic43 carcinoma cells, for example), antagonists of cb2 but not of cb1 inhibit cannabinoid antitumour actions
  • thc promotes cancer cell death in a cb1- or cb2-dependent manner (or both) at lower concentrations
  • cannabidiol (cbd), a phytocannabinoid with a low affinity for cannabinoid receptors15, and other marijuana-derived cannabinoids57 have also been proposed to promote the apoptotic death of cancer cells acting independently of the cb1 and cb2 receptors
  • In cancer cells, cannabinoids block the activation of the vascular endothelial growth factor (vegf) pathway, an inducer of angiogenesi
  • In vascular endothelial cells, cannabinoid receptor activation inhibits proliferation and migration, and induces apoptosis
  • cb1 or cb2 receptor agonists (or both) reduce the formation of distant tumour masses in animal models of both induced and spontaneous metastasis, and inhibit adhesion, migration, and invasiveness of glioma64, breast65,66, lung67,68, and cervical68 cancer cells in culture
  • the ceramide/p8–regulated pathway plays a general role in the antitumour activity of cannabinoids targeting cb1 and cb2
  • cbd, by acting independently of the cb1 and cb2 receptors, produces a remarkable anti-tumour effect—including reduction of invasiveness and metastasis
  • cannabinoids can also enhance immune system–mediated tumour surveillance in some contexts
  • ability of thc to reduce inflammation75,76, an effect that might prevent certain types of cancer
  • recent observations suggest that the combined administration of cannabinoids with other anticancer drugs acts synergistically to reduce tumour growth
  • combined administration of gemcitabine (the benchmark agent for the treatment of pancreatic cancer) and various cannabinoid agonists synergistically reduced the viability of pancreatic cancer cells
  • Other reports indicated that anandamide and HU-210 might also enhance the anticancer activity of paclitaxel89 and 5-fluorouracil90 respectively
  • Combined administration of thc and cbd enhances the anticancer activity of thc and reduces the dose of thc needed to induce its tumour growth-inhibiting activity
  • Preclinical animal models have yielded data indicating that systemic (oral or intraperitoneal) administration of cannabinoids effectively decreases tumour growth
  • Combinations of cannabinoids with classical chemotherapeutic drugs such as the alkylating agent temozolomide (the benchmark agent for the management of glioblastoma80,84) have been shown to produce a strong anticancer action in animal models
  • pharmacologic inhibition of egfr, erk83, or akt enhances the cell-death-promoting action of thc in glioma cultures (unpublished observations by the authors), which suggests that targeting egfr and the akt and erk pathways could enhance the antitumour effect of cannabinoids
  • Nathan Goodyear on 18 Sep 18
     
    Good review of the anticancer effects of cananbinoids.
Nathan Goodyear

Oxidative Stress and Stress-Activated Signaling Pathways: A Unifying Hypothesis of Type... - 0 views

edrv.endojournals.org/...599.long

free radicals oxidative stress damage inflammation type II DM alpha lipoic acid alpha-lipoic-acid diabetes

shared by Nathan Goodyear on 02 Aug 12 - No Cached
  • In patients with diabetes, LA levels are reduced (48, 74, 103). LA has long been used for the treatment of diabetic neuropathy in Germany
  • evidence indicates that it increases insulin sensitivity in patients with type 2 diabetes
  • LA has been shown to 1) quench free radicals, 2) prevent singlet oxygen-induced DNA damage, 3) exhibit chelating activity, 4) reduce lipid peroxidation, 5) increase intracellular glutathione levels, and 6) prevent glycation of serum albumin (73, 74). LA is able to reduce oxidative stress-mediated NF-κB activation in vitro (74, 108, 109) and in patients with type 2 diabetes
  • ...2 more annotations...
  • Activation of NF-κB can also be blocked by several other thiol-containing antioxidants including N-acetyl-l-cysteine (NAC)
  • Other clinically available antioxidants reported to have antiinflammatory, antioncogenic, and/or antiatherogenic properties that have been shown to block the activation of NF-κB include resveratrol (115, 116), (-)-epicatechin-3-gallate (117), pycnogenol (118), silymarin (119), and curcumin (120)
  • Nathan Goodyear on 02 Aug 12
     
    Great read!  If you want to see how free radicals and oxidative stress contribute to inflammation and disease (DM in this case), read this article.
Nathan Goodyear

Testosterone and the Cardiovascular System: A Comprehensive Review of the Clinical Lite... - 0 views

jaha.ahajournals.org/...e000272.full

Testosterone men male cardiovascular disease low T

shared by Nathan Goodyear on 20 Nov 13 - No Cached
  • Low endogenous bioavailable testosterone levels have been shown to be associated with higher rates of all‐cause and cardiovascular‐related mortality.39,41,46–47 Patients suffering from CAD,13–18 CHF,137 T2DM,25–26 and obesity27–28
  • have all been shown to have lower levels of endogenous testosterone compared with those in healthy controls. In addition, the severity of CAD15,17,29–30 and CHF137 correlates with the degree of testosterone deficiency
  • In patients with CHF, testosterone replacement therapy has been shown to significantly improve exercise tolerance while having no effect on LVEF
  • ...66 more annotations...
  • testosterone therapy causes a shift in the skeletal muscle of CHF patients toward a higher concentration of type I muscle fibers
  • Testosterone replacement therapy has also been shown to improve the homeostatic model of insulin resistance and hemoglobin A1c in diabetics26,68–69 and to lower the BMI in obese patients.
  • Lower levels of endogenous testosterone have been associated with longer duration of the QTc interval
  • testosterone replacement has been shown to shorten the QTc interval
  • negative correlation has been demonstrated between endogenous testosterone levels and IMT of the carotid arteries, abdominal aorta, and thoracic aorta
  • These findings suggest that men with lower levels of endogenous testosterone may be at a higher risk of developing atherosclerosis.
  • Current guidelines from the Endocrine Society make no recommendations on whether patients with heart disease should be screened for hypogonadism and do not recommend supplementing patients with heart disease to improve survival.
  • The Massachusetts Male Aging Study also projects ≈481 000 new cases of hypogonadism annually in US men within the same age group
  • since 1993 prescriptions for testosterone, regardless of the formulation, have increased nearly 500%
  • Testosterone levels are lower in patients with chronic illnesses such as end‐stage renal disease, human immunodeficiency virus, chronic obstructive pulmonary disease, type 2 diabetes mellitus (T2DM), obesity, and several genetic conditions such as Klinefelter syndrome
  • A growing body of evidence suggests that men with lower levels of endogenous testosterone are more prone to develop CAD during their lifetimes
  • There are 2 major potential confounding factors that the older studies generally failed to account for. These factors are the subfraction of testosterone used to perform the analysis and the method used to account for subclinical CAD.
  • The biologically inactive form of testosterone is tightly bound to SHBG and is therefore unable to bind to androgen receptors
  • The biologically inactive fraction of testosterone comprises nearly 68% of the total testosterone in human serum
  • The biologically active subfraction of testosterone, also referred to as bioavailable testosterone, is either loosely bound to albumin or circulates freely in the blood, the latter referred to as free testosterone
  • It is estimated that ≈30% of total serum testosterone is bound to albumin, whereas the remaining 1% to 3% circulates as free testosterone
  • it can be argued that using the biologically active form of testosterone to evaluate the association with CAD will produce the most reliable results
  • English et al14 found statistically significant lower levels of bioavailable testosterone, free testosterone, and free androgen index in patients with catheterization‐proven CAD compared with controls with normal coronary arteries
  • patients with catheterization‐proven CAD had statistically significant lower levels of bioavailable testosterone
  • In conclusion, existing evidence suggests that men with CAD have lower levels of endogenous testosterone,13–18 and more specifically lower levels of bioavailable testosterone
  • low testosterone levels are associated with risk factors for CAD such as T2DM25–26 and obesity
  • In a meta‐analysis of these 7 population‐based studies, Araujo et al41 showed a trend toward increased cardiovascular mortality associated with lower levels of total testosterone, but statistical significance was not achieved (RR, 1.25
  • the authors showed that a decrease of 2.1 standard deviations in levels of total testosterone was associated with a 25% increase in the risk of cardiovascular mortality
  • the relative risk of all‐cause mortality in men with lower levels of total testosterone was calculated to be 1.35
  • higher risk of cardiovascular mortality is associated with lower levels of bioavailable testosterone
  • Existing evidence seems to suggest that lower levels of endogenous testosterone are associated with higher rates of all‐cause mortality and cardiovascular mortality
  • studies have shown that lower levels of endogenous bioavailable testosterone are associated with higher rates of all‐cause and cardiovascular mortality
  • It may be possible that using bioavailable testosterone to perform mortality analysis will yield more accurate results because it prevents the biologically inactive subfraction of testosterone from playing a potential confounding role in the analysis
  • The earliest published material on this matter dates to the late 1930s
  • the concept that testosterone replacement therapy improves angina has yet to be proven wrong
  • In more recent studies, 3 randomized, placebo‐controlled trials demonstrated that administration of testosterone improves myocardial ischemia in men with CAD
  • The improvement in myocardial ischemia was shown to occur in response to both acute and chronic testosterone therapy and seemed to be independent of whether an intravenous or transdermal formulation of testosterone was used.
  • testosterone had no effect on endothelial nitric oxide activity
  • There is growing evidence from in vivo animal models and in vitro models that testosterone induces coronary vasodilation by modulating the activity of ion channels, such as potassium and calcium channels, on the surface of vascular smooth muscle cells
  • Experimental studies suggest that the most likely mechanism of action for testosterone on vascular smooth muscle cells is via modulation of action of non‐ATP‐sensitive potassium ion channels, calcium‐activated potassium ion channels, voltage‐sensitive potassium ion channels, and finally L‐type calcium ion channels
  • Corona et al confirmed those results by demonstrating that not only total testosterone levels are lower among diabetics, but also the levels of free testosterone and SHBG are lower in diabetic patients
  • Laaksonen et al65 followed 702 Finnish men for 11 years and demonstrated that men in the lowest quartile of total testosterone, free testosterone, and SHBG were more likely to develop T2DM and metabolic syndrome.
  • Vikan et al followed 1454 Swedish men for 11 years and discovered that men in the highest quartile of total testosterone were significantly less likely to develop T2DM
  • authors demonstrated a statistically significant increase in the incidence of T2DM in subjects receiving gonadotropin‐releasing hormone antagonist therapy. In addition, a significant increase in the rate of myocardial infarction, stroke, sudden cardiac death, and development of cardiovascular disease was noted in patients receiving antiandrogen therapy.67
  • Several authors have demonstrated that the administration of testosterone in diabetic men improves the homeostatic model of insulin resistance, hemoglobin A1c, and fasting plasma glucose
  • Existing evidence strongly suggests that the levels of total and free testosterone are lower among diabetic patients compared with those in nondiabetics
  • insulin seems to be acting as a stimulant for the hypothalamus to secret gonadotropin‐releasing hormone, which consequently results in increased testosterone production. It can be argued that decreased stimulation of the hypothalamus in diabetics secondary to insulin deficiency could result in hypogonadotropic hypogonadism
  • BMI has been shown to be inversely associated with testosterone levels
  • This interaction may be a result of the promotion of lipolysis in abdominal adipose tissue by testosterone, which may in turn cause reduced abdominal adiposity. On the other hand, given that adipose tissue has a higher concentration of the enzyme aromatase, it could be that increased adipose tissue results in more testosterone being converted to estrogen, thereby causing hypogonadism. Third, increased abdominal obesity may cause reduced testosterone secretion by negatively affecting the hypothalamus‐pituitary‐testicular axis. Finally, testosterone may be the key factor in activating the enzyme 11‐hydroxysteroid dehydrogenase in adipose tissue, which transforms glucocorticoids into their inactive form.
  • increasing age may alter the association between testosterone and CRP. Another possible explanation for the association between testosterone level and CRP is central obesity and waist circumference
  • Bai et al have provided convincing evidence that testosterone might be able to shorten the QTc interval by augmenting the activity of slowly activating delayed rectifier potassium channels while simultaneously slowing the activity of L‐type calcium channels
  • consistent evidence that supplemental testosterone shortens the QTc interval.
  • Intima‐media thickness (IMT) of the carotid artery is considered a marker for preclinical atherosclerosis
  • Studies have shown that levels of endogenous testosterone are inversely associated with IMT of the carotid artery,126–128,32,129–130 as well as both the thoracic134 and the abdominal aorta
  • 1 study has demonstrated that lower levels of free testosterone are associated with accelerated progression of carotid artery IMT
  • another study has reported that decreased levels of total and bioavailable testosterone are associated with progression of atherosclerosis in the abdominal aorta
  • These findings suggest that normal physiologic testosterone levels may help to protect men from the development of atherosclerosis
  • Czesla et al successfully demonstrated that the muscle specimens that were exposed to metenolone had a significant shift in their composition toward type I muscle fibers
  • Type I muscle fibers, also known as slow‐twitch or oxidative fibers, are associated with enhanced strength and physical capability
  • It has been shown that those with advanced CHF have a higher percentage of type II muscle fibers, based on muscle biopsy
  • Studies have shown that men with CHF suffer from reduced levels of total and free testosterone.137 It has also been shown that reduced testosterone levels in men with CHF portends a poor prognosis and is associated with increased CHF mortality.138 Reduced testosterone has also been shown to correlate negatively with exercise capacity in CHF patients.
  • Testosterone replacement therapy has been shown to significantly improve exercise capacity, without affecting LVEF
  • the results of the 3 meta‐analyses seem to indicate that testosterone replacement therapy does not cause an increase in the rate of adverse cardiovascular events
  • Data from 3 meta‐analyses seem to contradict the commonly held belief that testosterone administration may increase the risk of developing prostate cancer
  • One meta‐analysis reported an increase in all prostate‐related adverse events with testosterone administration.146 However, when each prostate‐related event, including prostate cancer and a rise in PSA, was analyzed separately, no differences were observed between the testosterone group and the placebo group
  • the existing data from the 3 meta‐analyses seem to indicate that testosterone replacement therapy does not increase the risk of adverse cardiovascular events
  • the authors correctly point out the weaknesses of their study which include retrospective study design and lack of randomization, small sample size at extremes of follow‐up, lack of outcome validation by chart review and poor generalizability of the results given that only male veterans with CAD were included in this study
    • Nathan Goodyear
      Nathan Goodyear on 04 Dec 13
       
      The authors here present Total Testosterone as a "confounding" value
    • Nathan Goodyear
      Nathan Goodyear on 09 Dec 13
       
      This would be HSD-II
  • the studies that failed to find an association between testosterone and CRP used an older population group
  • low testosterone may influence the severity of CAD by adversely affecting the mediators of the inflammatory response such as high‐sensitivity C‐reactive protein, interleukin‐6, and tumor necrosis factor–α
  • Nathan Goodyear on 20 Nov 13
     
    Good review of Testosterone and CHD.  Low T is associated with increased all cause mortality and cardiovascular mortality, CAD, CHF, type II diabetes, obesity, increased IMT,  increased severity of CAD and CHF.  Testosterone replacement in men with low T has been shown to improve exercise tolerance in CHF, improve insulin resistance, improve HgbA1c and lower BMI in the obese.
Nathan Goodyear

Serum thymidine kinase 1 correlates to clinical stages and clinical reactions and monit... - 0 views

c.na2.content.force.com/...ervlet.EmailAttachmentDownload

thymidine kinase 1 TK-1 cancer

shared by Nathan Goodyear on 26 Jan 15 - No Cached
  • Nathan Goodyear on 26 Jan 15
     
    TK-1 to screen for cancer, as well as to follow therapy and recurrence.
Nathan Goodyear

Update on Programmed Death-1 and Programmed Death-Ligand 1 Inhibition in the Treatment ... - 0 views

www.ncbi.nlm.nih.gov/...PMC5382272

cancer PD-1 immunotherapy programmed death-1

shared by Nathan Goodyear on 20 Apr 18 - No Cached
  • Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), the first immune checkpoint receptor to be clinically targeted, is exclusively expressed on the surface of CD4+ and CD8+ T cells in lymphatic tissue and is involved in T-cell regulation, proliferation, and tolerance
  • programmed death-1 (PD-1) immune checkpoint inhibitor antibodies, which restores T-cell effector function and augments the host anti-tumor response by blocking the binding of either programmed death-ligand 1 (PD-L1) and/or PD-L2 to PD-1 receptors
  • lung cancer is the first and second cause of cancer mortality in men and women
  • ...1 more annotation...
  • Eighty-five percent of lung cancers are non-small-cell lung cancer (NSCLC)
  • Nathan Goodyear on 20 Apr 18
     
    To read update article on PD-1 and immunotherapy.
Nathan Goodyear

Development of PD-1/PD-L1 Pathway in Tumor Immune Microenvironment and Treatment for No... - 0 views

www.nature.com/...srep13110

PD-1 cancer check point inhibitors PD-L1 CLTA-4 immunotherapy

shared by Nathan Goodyear on 20 Apr 18 - No Cached
  • the lack of immunologic control is recognized as a hallmark of cancer currently
  • Programmed death-1 (PD-1) and its ligand PD-L1 play a key role in tumor immune escape and the formation of tumor microenvironment, closely related with tumor generation and development
  • Blockading the PD-1/PD-L1 pathway could reverse the tumor microenvironment and enhance the endogenous antitumor immune responses.
  • ...4 more annotations...
  • environmental factors, living habits, genetic mutations, dysfunction of the immune system and so on
  • special tumor immune microenvironment
  • cytotoxic T lymphocyte-associated antigen 4 (CLTA-4), Programmed death-1 (PD-1) and its ligands PD-L1 (B7H1) and PD-L2 (B7-DC)
  • CTLA-4 regulates T cell activity in the early stage predominantly, and PD-1 mainly limits the activity of T-cell in the tumor microenvironment at later stage of tumor growth
  • Nathan Goodyear on 20 Apr 18
     
    PD-1 to read.
Nathan Goodyear

http://annonc.oxfordjournals.org/content/12/11/1533.full.pdf#page=1&view=FitH - 0 views

annonc.oxfordjournals.org/...1533.full.pdf

cancer carbohydrates insulin breast cancer diet nutrition glycemic index glycemic load IGF-1 SHBG

shared by Nathan Goodyear on 09 Dec 14 - No Cached
  • Nathan Goodyear on 09 Dec 14
     
    Study finds link between higher glycemic index and glycemic load with increased breast cancer risk.   The proposed mechanisms are: hyperinsulinemia and its affinity for IGF-1 receptor resulting in a + growth signal.  Increased IGF-1 via the same mechanism. Insulin and IGF-1 have negative regulation effects on SHBG. This all makes sense as insulin receptors are highly expressed on cancer cells.
Nathan Goodyear

Nuclear TK1 expression is an independent prognostic factor for survival in pre-malignan... - 0 views

www.ncbi.nlm.nih.gov/...PMC3665464

TK-1 TK-1 cancer thymidine kinase 1 cancer biomarker

shared by Nathan Goodyear on 04 Mar 15 - No Cached
  • Thymidine kinase 1 (TK1) is a proliferation biomarker
  • Nuclear TK1 expression in early grade CIN predicts risk for progression to malignancy
  • Nuclear TK1 expression is also a prognostic factor for treatment outcome
  • ...9 more annotations...
  • TK1 LI was found to be a more reliable prognostic marker for 5-year survival than pathological stages, FIGO stages and Ki-67,
  • nuclear TK1 expression is a reliable prognostic factor in CIN patients, a group of cervical lesion patients that respond positively to treatment
  • nuclear TK1 expression is correlated with advanced stage of invasive cervical carcinomas
  • a low TK1 LI can help to identify with a better survival
  • low TK1 expression in the tumors in these patients might indicate that these tumors have a lower proliferation rate
  • TK1 is a key kinase in the one-step salvage pathway by which thymidine is introduced into DNA via the salvage pathway
  • TK1 participates in DNA synthesis and is therefore closely related to the S-phase of the cell cycle, and is correlated with proliferation
  • TK1 intensity (TK1 synthesis rate) increases from CIN grade I to CIN grade III, but does not further increase in invasive cervical carcinomas.
  • TK1 intensity seems to be a prognostic factor particularly when pre-malignant cervical lesions progress to malignancy
  • Nathan Goodyear on 04 Mar 15
     
    TK-1 is a proliferation biomarker of DNA repair. TK-1 is a nuclear biomarker of cancer prognosis, survival, recurrence and predicts risk of progression of pre-malignant disease.
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