Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UMLS:C0596263 (carcinogenesis)
64,820 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Adiponectin is a peptide hormone secreted exclusively by adipocytes, and obesity is an established risk factor for breast cancer. We have, thus, evaluated the associations of anthropometric measures of adiposity and adiponectin with the development of breast cancer in a case-control study. Questionnaire information, anthropometric measures, and blood samples were taken before treatment from 244 incident cases with breast cancer, including 141 premenopausal and 103 postmenopausal cases, and 244 controls admitted for health examination at the Tri-Service General Hospital, Taipei between 2004 and 2005. Plasma levels of adiponectin were measured by RIA. The relationship between anthropometric measures of adiposity and breast cancer risk was modified by menopausal status, with a significant increase in risk observed in postmenopausal but not premenopausal women. Moreover, a fairly robust inverse association of adiponectin with the risk was observed only in postmenopausal women (adjusted odds ratio (OR), 0.55; 95% confidence interval (CI), 0.23-0.97), but not in premenopausal women. Additionally, the plasma adiponectin levels tended to be inversely associated with estrogen receptor (ER)-positive (adjusted OR, 0.53; 95% CI, 0.27-0.98) but not ER-negative breast tumors. Furthermore, the associations of adiponectin with breast cancer risk overall and by menopausal and ER status remained after adjustment for obesity indices. These results suggest that adiponectin may have an independent role in breast carcinogenesis, particularly in the postmenopausal and ER-positive breast cancer risk.
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PMID:Anthropometric measures, plasma adiponectin, and breast cancer risk. 1791 97

Adipocytokines are a group of adipocyte-secreted proteins that have significant effects on the metabolism of lipids and carbohydrates, as well as numerous other processes. A number of recent studies have indicated that some adipocytokines may significantly influence the proliferation of malignant cells in vitro, whereas it remains unclear whether they have similar roles in vivo. In this study, we determined serum levels of adipocytokines in mice with azoxymethane (AOM)- and dextran sulfate sodium (DSS)-induced colon carcinogenesis. Five-week-old ICR mice were given a single intraperitoneal injection of AOM followed by 1% DSS in drinking water for 7 days. Nobiletin (NOB), a citrus flavonoid, was given in the diet (100 p.p.m) for 17 weeks. Thereafter, the incidence and number of colon tumors and serum concentration of adipocytokines were determined at the end of week 20. The serum leptin level in AOM/DSS-treated mice was six times higher than that in untreated mice, whereas there were no significant differences in the levels of triglycerides, adiponectin and interleukin-6. Feeding with NOB abolished colonic malignancy and notably decreased the serum leptin level by 75%. Further, NOB suppressed the leptin-dependent, but not independent, proliferation of HT-29 colon cancer cells and decreased leptin secretion through inactivation of mitogen-activated protein kinase/extracellular signaling-regulated protein kinase, but not that of adiponectin in differentiated 3T3-L1 mouse adipocytes in a dose-dependent manner. Taken together, our results suggest that higher levels of leptin in serum promote colon carcinogenesis in mice, whereas NOB has chemopreventive effects against colon carcinogenesis, partly through regulation of leptin levels.
Carcinogenesis 2008 May
PMID:Suppressive effects of nobiletin on hyperleptinemia and colitis-related colon carcinogenesis in male ICR mice. 1837 60

Rates of adenocarcinoma of the esophagus (EAC) and esophagogastric junction (EGJAC) have been rising rapidly in recent decades, in contrast to the declining rates of esophageal squamous cell carcinomas (ESCC). Obesity is a major risk factor for both EAC and EGJAC, but not ESCC, and there is speculation that obesity promotes adenocarcinoma development through endocrine and related pathways. We therefore compared the prevalence of 12 single nucleotide polymorphisms (SNPs) in nine candidate genes previously implicated in obesity pathways (LEP, LEPR, ADIPOQ, POMC, PPARalpha, PPARgamma, RXRgamma, GHRL, and INSIG2) in a large Australian case-control study comprising DNA samples from 260 EAC cases, 301 EGJAC cases, 213 ESCC cases, and 1,352 population controls. No SNPs were associated with EGJAC or ESCC. Although several SNPs seemed to be associated with EAC on crude analysis [ADIPOQ (rs1501299), LEP (5'-untranslated region), PPARgamma (H447H), and GHRL (M72L)], effect sizes were modest and none of the associations was significant after correcting for multiple comparisons. Further, we found no consistent evidence that any of the genotypes were associated with risk of EAC or EGJAC within strata of body mass index (<25.0 kg/m(2), 25.0-29.9 kg/m(2), >30 kg/m(2)). In conclusion, our data suggest that these SNPs do not play a major role in esophageal carcinogenesis.
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PMID:Single nucleotide polymorphisms in obesity-related genes and the risk of esophageal cancers. 1839 47

The only universally accepted risk factors for the development of pancreatic cancer are a positive family history or a history of smoking. Although the contribution of pancreatitis to pancreatic carcinogenesis has been debated for decades in the epidemiology literature, the actual mechanism is still unclear. With the rising epidemic of obesity, scientists have begun to focus on the contribution of chronic inflammatory state of morbidly obese patients in an effort to better understand the contribution of inflammation to the comorbidities of obesity. Notably, population studies are beginning to show that one of the most serious potential comorbidities of obesity is an increased lifetime risk of developing cancer. In this article, the current literature that exists supporting this Chronic Inflammatory Hypothesis as it pertains to obesity and pancreatic carcinogenesis is reviewed. To date, studies have focused on interleukin-6, a cytokine known to play a role in obesity, chronic pancreatitis and pancreatic cancer. The anti-inflammatory adipocytokine, adiponectin, has also shown promise as a key player in this mechanism and has recently been found to be more specific than standard tumor markers in differentiating pancreatic cancer from chronic pancreatitis. If the pathogenesis of pancreatic cancer is related to hormone levels associated with obesity, such as adipocytokines, and cytokines associated with chronic inflammation, this could potentially lead to the development of new pancreatic cancer tumor markers and ultimately new therapies and methods of prevention.
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PMID:Obesity, pancreatitis, and pancreatic cancer. 1856 97

Adiponectin is secreted by adipocytes and is a key hormone responsible for insulin sensitization. Recent studies have shown that plasma adiponectin is decreased in patients with breast, endometrial and gastric cancer. However, the effect of adiponectin on colorectal carcinogenesis is controversial. It is now well known that the adiponectin receptor exists in two isoforms, adiponectin receptor 1 (AdipoR1) and adiponectin receptor 2 (AdipoR2). We examined the expression of the adiponectin receptors on normal colon mucosa and colon cancer tissues in a human study using real-time RT-PCR, Western blotting and immunohistochemical staining. Adiponectin receptors, AdipoR1/AdipoR2, were expressed in normal colon epithelial and colon cancer cells. Furthermore, laser microdissection was performed to confirm our results. These results suggest that adiponectin may exert some effects on normal colon epithelium or colon cancer cells directly through adiponectin receptors. Further studies are required to elucidate the function of the AdipoRs activated by adiponectin and the downstream mechanisms of AdipoRs in colon cancer cells.
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PMID:Expression of adiponectin receptors, AdipoR1 and AdipoR2, in normal colon epithelium and colon cancer tissue. 1869 95

The endocannabinoid system (ECS) consists of two receptors (CB(1) and CB(2)), several endogenous ligands (primarily anandamide and 2-AG), and over a dozen ligand-metabolizing enzymes. The ECS has deep phylogenetic roots and regulates many aspects of embryological development and homeostasis, including neuroprotection and neural plasticity, immunity and inflammation, apoptosis and carcinogenesis, pain and emotional memory, and the focus of this review: hunger, feeding, and metabolism. The ECS controls energy balance and lipid metabolism centrally (in the hypothalamus and mesolimbic pathways) and peripherally (in adipocytes and pancreatic islet cells), acting through numerous anorexigenic and orexigenic pathways (e.g., ghrelin, leptin, orexin, adiponectin, endogenous opioids, and corticotropin-releasing hormone). Obesity leads to excessive endocannabinoid production by adipocytes, which drives CB(1) in a feed-forward dysfunction. Phylogenetic research suggests the genes for endocannabinoid enzymes, especially DAGLalpha and NAPE-PLD, may harbor mildly deleterious alleles that express disease-related phenotypes. Several CB(1) inverse agonists have been developed for the treatment of obesity, including rimonabant, taranabant, and surinabant. These drugs are efficacious at reducing food intake as well as abdominal adiposity and cardiometabolic risk factors. However, given the myriad beneficial roles of the ECS, it should be no surprise that systemic CB(1) blockade induces various adverse effects. Alternatives to systemic blockade include CB(1) partial agonists, pleiotropic drugs, peripherally restricted antagonists, allosteric antagonists, and endocannabinoid ligand modulation. The ECS offers several discrete targets for the management of obesity and its associated cardiometabolic sequelae.
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PMID:Critical role of the endocannabinoid system in the regulation of food intake and energy metabolism, with phylogenetic, developmental, and pathophysiological implications. 1878 18

The association between obesity and the risk of colorectal cancer (CRC) cannot be easily evaluated because CRC itself is associated with a gradual loss of bodyweight. Aberrant crypt foci (ACF) can be classified as dysplastic ACF or non-dysplastic ACF by magnifying colonoscopy, and dysplastic ACF are thought to be a biomarker of CRC. Ninety-four participants who underwent colonoscopy at Yokohama City University Hospital, Japan, were enrolled in the current study. We detected 557 ACF, including 67 dysplastic ACF (12.0%). Univariate regression analysis was conducted to determine correlations between the number of dysplastic ACF and various potential risk factors, including patient age, waist circumference, body mass index, visceral fat area (VFA), and plasma adiponectin level. The results of multiple regression analysis revealed that the number of dysplastic ACF correlated with age (correlation coefficient r=0.212, P=0.0383) and plasma adiponectin level (r=-0.201, P=0.0371), even after adjustments for sex, waist circumference, body mass index, and VFA. Our univariate correlation analysis data showed a significant correlation with the number of dysplastic ACF with VFA (r=0.238, P=0.0209), no correlation with subcutaneous fat area, and an inverse correlation with the plasma level of adiponectin (r=-0.258, P=0.0118). Thus, our results suggest that aging and visceral fat accumulation could correlate moderately with colorectal carcinogenesis. The novelty of our study lies in the finding that visceral fat accumulation and a low plasma adiponectin level may promote colorectal carcinogenesis; therefore, these obesity-related parameters may serve as novel targets for CRC prevention.
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PMID:Association of visceral fat accumulation and plasma adiponectin with rectal dysplastic aberrant crypt foci in a clinical population. 1901 60

Adiposity and adipocyte-derived cytokines have been implicated in prostate carcinogenesis. However, the relationship of adipokine gene variants with prostate cancer risk has not been thoroughly investigated. We therefore examined common variants of the IL6, LEP, LEPR, TNF and ADIPOQ genes in relation to prostate cancer in a case-control study nested within a large cohort of Finnish men. The study sample consisted of 1,053 cases of prostate cancer, diagnosed over an average 11 years of follow up, and 1,053 controls matched to the cases on age, intervention group and date of baseline blood draw. Logistic regression was used to model the relative odds of prostate cancer. We also examined genotypes in relation to serum insulin, IGF-1 and IGF-1:IGFBP-3 among 196 controls. Variant alleles at three loci (-14858A>G, -13973A>C, -13736C>A) in a potential regulatory region of the LEP gene conferred a statistically significant 20% reduced risk of prostate cancer. For example, at the -14858A>G locus, heterozygotes and homozygotes for the A allele had an odds ratio (OR) of prostate cancer of 0.76 [95% confidence interval (CI) 0.62, 0.93] and 0.79 (95% CI 0.60, 1.04), respectively. At 13288G>A, relative to the GG genotype, the AA genotype was associated with a suggestive increased risk of prostate cancer (OR = 1.29; 95% CI 0.99,1.67; p(trend) = 0.05). Polymorphisms in the IL6, LEPR, TNF and ADIPOQ genes were not associated with prostate cancer. Allelic variants in the LEP gene are related to prostate cancer risk, supporting a role for leptin in prostate carcinogenesis.
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PMID:Adipokine genes and prostate cancer risk. 1903 56

Obesity, particularly visceral adiposity, is an established risk factor for colorectal cancer (CRC) and this is thought to result, at least in part, from insulin resistance and chronic hyperinsulinemia that may be mediated by adipokines. Serum levels of adiponectin, the most abundant protein secreted from adipocytes, are decreased in obesity and are inversely associated with insulin resistance and hyperinsulinemia. The objective of this study was to determine whether elevated circulating adiponectin plays a role in colon carcinogenesis using adiponectin transgenic (AdTg) mice that have 2-3-fold elevated circulating adiponectin but similar body weights as wildtype (WT) littermates used as controls. Eight-week old male and female AdTg and WT mice were treated with 4 weekly injections of the colon-specific carcinogen azoxymethane (AOM). One week following the last dose of AOM, all mice were placed on a high-fat diet and killed 24 weeks later, at 36 weeks of age, for the analysis of colon tumors. Glucose tolerance tests (GTT) were performed by injecting 2g/kg dextrose or 1.25-1.5 g/kg dextrose into all 12-week and 32-35-week-old mice respectively, and measuring blood from the tail vein 15, 30, 60 and 120 min following glucose administration. There were no significant differences in colon tumor incidence, number or size between AdTg and WT mice of either sex. AdTg mice of both sexes displayed resistance to diet-induced decreases in insulin sensitivity. Our results show that constitutively elevated levels of circulating adiponectin in AdTg mice do not confer protection against the development of colon tumors.
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PMID:Elevated circulating adiponectin and elevated insulin sensitivity in adiponectin transgenic mice are not associated with reduced susceptibility to colon carcinogenesis. 1954 61

In 2005, a Japanese epidemiological study showed that increase in plasma glucose levels is a risk factor for gastric cancer. However, no animal model has hitherto shown any association between diabetes mellitus and neoplasia in the stomach. Diabetic (db/db) mice have obese and diabetic phenotypes, including hyperglycemia, because of disruption of the leptin receptor. In the present study, effects of hyperglycemia and/or hyperinsulinemia on the development of proliferative lesions were therefore examined in db/db mice given N-methyl-N-nitrosourea (MNU). A total of 120 mice were assigned to four groups: Group A, 40 db/db mice with MNU; Group B, 40 + /db mice with MNU; Group C, 30 misty (wild-type) mice with MNU; Group D, 10 db/db mice without MNU. MNU was given at 60 ppm in drinking water for 20 weeks. Subgroups of animals were sacrificed at weeks 21 and 30 and blood samples were collected to measure glucose, insulin, leptin, and adiponectin concentrations. The removed stomachs were fixed in formalin, and embedded in paraffin for histological examination and immunohistochemistry. At week 30 in Groups A, B, C and D, hyperplasia was observed in 100, 79, 57, and 0%, and dysplasia in 91, 43, 71, and 0%, respectively. Adenocarcinomas and pepsinogen-altered pyloric glands (PAPG), putative preneoplastic lesions, were observed only in Group A, at an incidence of 45%. The serum levels of insulin and leptin were also elevated in Group A. Gastric carcinogenesis by MNU was enhanced in db/db mice, possibly in association with hyperinsulinemia and hyperleptinemia.
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PMID:Gastric carcinogenesis by N-Methyl-N-nitrosourea is enhanced in db/db diabetic mice. 1943 3


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