Effect of processed and red meat on endogenous nitrosation and DNA damage

Haem in red meat (RM) stimulates the endogenous production of mutagenic nitroso compounds (NOC). Processed (nitrite-preserved red) meat additionally contains high concentrations of preformed NOC. In two studies, of a fresh RM versus a vegetarian (VEG) diet (six males and six females) and of a nitrite-preserved red meat (PM) versus a VEG diet (5 males and 11 females), we investigated whether processing of meat might increase colorectal cancer risk by stimulating nitrosation and DNA damage. Meat diets contained 420 g (males) or 366 g (females) meat/per day. Faecal homogenates from day 10 onwards were analysed for haem and NOC and associated supernatants for genotoxicity. Means are adjusted for differences in male to female ratios between studies. Faecal NOC concentrations on VEG diets were low (2.6 and 3.5 mmol/g) but significantly higher on meat diets (PM 175 ± 19 nmol/g versus RM 185 ± 22 nmol/g; P = 0.75). The RM diet resulted in a larger proportion of nitrosyl iron (RM 78% versus PM 54%; P < 0.0001) and less nitrosothiols (RM 12% versus PM 19%; P < 0.01) and other NOC (RM 10% versus PM 27%; P < 0.0001). There was no statistically significant difference in DNA breaks induced by faecal water (FW) following PM and RM diets (P = 0.80). However, PM resulted in higher levels of oxidized pyrimidines (P < 0.05). Surprisingly, VEG diets resulted in significantly more FW-induced DNA strand breaks than the meat diets (P < 0.05), which needs to be clarified in further studies. Meats cured with nitrite have the same effect as fresh RM on endogenous nitrosation but show increased FW-induced oxidative DNA damage

Vitamin D supplementation and breast cancer prevention : a systematic review and meta-analysis of randomized clinical trials

In recent years, the scientific evidence linking vitamin D status or supplementation to breast cancer has grown notably. To investigate the role of vitamin D supplementation on breast cancer incidence, we conducted a systematic review and meta-analysis of randomized controlled trials comparing vitamin D with placebo or no treatment. We used OVID to search MEDLINE (R), EMBASE and CENTRAL until April 2012. We screened the reference lists of included studies and used the “Related Article” feature in PubMed to identify additional articles. No language restrictions were applied. Two reviewers independently extracted data on methodological quality, participants, intervention, comparison and outcomes. Risk Ratios and 95% Confident Intervals for breast cancer were pooled using a random-effects model. Heterogeneity was assessed using the I2 test. In sensitivity analysis, we assessed the impact of vitamin D dosage and mode of administration on treatment effects. Only two randomized controlled trials fulfilled the pre-set inclusion criteria. The pooled analysis included 5372 postmenopausal women. Overall, Risk Ratios and 95% Confident Intervals were 1.11 and 0.74–1.68. We found no evidence of heterogeneity. Neither vitamin D dosage nor mode of administration significantly affected breast cancer risk. However, treatment efficacy was somewhat greater when vitamin D was administered at the highest dosage and in combination with calcium (Risk Ratio 0.58, 95% Confident Interval 0.23–1.47 and Risk Ratio 0.93, 95% Confident Interval 0.54–1.60, respectively). In conclusions, vitamin D use seems not to be associated with a reduced risk of breast cancer development in postmenopausal women. However, the available evidence is still limited and inadequate to draw firm conclusions. Study protocol code: FARM8L2B5L

A hepatoprotective Lindera obtusiloba extract suppresses growth and attenuates insulin like growth factor-1 receptor signaling and NF-kappaB activity in human liver cancer cell lines

<p>Abstract</p> <p>Background</p> <p>In traditional Chinese and Korean medicine, an aqueous extract derived from wood and bark of the Japanese spice bush <it>Lindera obtusiloba </it>(<it>L.obtusiloba</it>) is applied to treat inflammations and chronic liver diseases including hepatocellular carcinoma. We previously demonstrated anti-fibrotic effects of <it>L.obtusiloba </it>extract in hepatic stellate cells. Thus, we here consequently examine anti-neoplastic effects of <it>L.obtusiloba </it>extract on human hepatocellular carcinoma (HCC) cell lines and the signaling pathways involved.</p> <p>Methods</p> <p>Four human HCC cell lines representing diverse stages of differentiation were treated with <it>L.obtusiloba </it>extract, standardized according to its known suppressive effects on proliferation and TGF-β-expression. Beside measurement of proliferation, invasion and apoptosis, effects on signal transduction and NF-κB-activity were determined.</p> <p>Results</p> <p><it>L.obtusiloba </it>extract inhibited proliferation and induced apoptosis in all HCC cell lines and provoked a reduced basal and IGF-1-induced activation of the IGF-1R signaling cascade and a reduced transcriptional NF-κB-activity, particularly in the poorly differentiated SK-Hep1 cells. Pointing to anti-angiogenic effects, <it>L.obtusiloba </it>extract attenuated the basal and IGF-1-induced expression of hypoxia inducible factor-1α, vascular endothelial growth factor, peroxisome proliferator-activated receptor-γ, cyclooxygenase-2 and inducible nitric oxide synthase.</p> <p>Conclusions</p> <p>The traditional application of the extract is confirmed by our experimental data. Due to its potential to inhibit critical receptor tyrosine kinases involved in HCC progression via the IGF-1 signaling pathway and NF-κB, the standardized <it>L.obtusiloba </it>extract should be further analysed for its active compounds and explored as (complementary) treatment option for HCC.</p

The effect of body weight on altered expression of nuclear receptors and cyclooxygenase-2 in human colorectal cancers

<p>Abstract</p> <p>Background</p> <p>Epidemiological studies on risk factors for colorectal cancer (CRC) have mainly focused on diet, and being overweight is now recognized to contribute significantly to CRC risk. Overweight and obesity are defined as an excess of adipose tissue mass and are associated with disorders in lipid metabolism. Peroxisome proliferator-activated receptors (PPARs) and retinoid-activated receptors (RARs and RXRs) are important modulators of lipid metabolism and cellular homeostasis. Alterations in expression and activity of these ligand-activated transcription factors might be involved in obesity-associated diseases, which include CRC. Cyclooxygenase-2 (COX-2) also plays a critical role in lipid metabolism and alterations in COX-2 expression have already been associated with unfavourable clinical outcomes in epithelial tumors. The objective of this study is to examine the hypothesis questioning the relationship between alterations in the expression of nuclear receptors and COX-2 and the weight status among male subjects with CRC.</p> <p>Method</p> <p>The mRNA expression of the different nuclear receptor subtypes and of COX-2 was measured in 20 resected samples of CRC and paired non-tumor tissues. The association between expression patterns and weight status defined as a body mass index (BMI) was statistically analyzed.</p> <p>Results</p> <p>No changes were observed in PPARγ mRNA expression while the expression of PPARδ, retinoid-activated receptors and COX-2 were significantly increased in cancer tissues compared to normal colon mucosa (<it>P </it>≤ 0.001). The weight status appeared to be an independent factor, although we detected an increased level of COX-2 expression in the normal mucosa from overweight patients (BMI ≥ 25) compared to subjects with healthy BMI (<it>P </it>= 0.002).</p> <p>Conclusion</p> <p>Our findings show that alterations in the pattern of nuclear receptor expression observed in CRC do not appear to be correlated with patient weight status. However, the analysis of COX-2 expression in normal colon mucosa from subjects with a high BMI suggests that COX-2 deregulation might be driven by excess weight during the colon carcinogenesis process.</p

An immunohistochemical perspective of PPARβ and one of its putative targets PDK1 in normal ovaries, benign and malignant ovarian tumours

Peroxisome proliferator-activated receptor β (PPARβ) is a member of the nuclear hormone receptor family and is a ligand-activated transcription factor with few known molecular targets including 3-phosphoinositide-dependent protein kinase 1(PDK1). In view of the association of PPARβ and PDK1 with cancer, we have examined the expression of PPARβ and PDK1 in normal ovaries and different histological grades of ovarian tumours. Normal ovaries, benign, borderline, grades 1, 2 and 3 ovarian tumours of serous, muciuous, endometrioid, clear cell and mixed subtypes were analysed by immunohistochemistry for PPARβ and PDK1 expression. All normal ovarian tissues, benign, borderline and grade 1 tumours showed PPARβ staining localised in the epithelium and stroma. Staining was predominantly nuclear, but some degree of cytoplasmic staining was also evident. Approximately 20% of grades 2 and 3 tumours lacked PPARβ staining, whereas the rest displayed some degree of nuclear and cytoplasmic staining of the scattered epithelium and stroma. The extent of epithelial and stromal PPARβ staining was significantly different among the normal and the histological grades of tumours (χ2=59.25, d.f.=25, P<0.001; χ2=64.48, d.f.=25, P<0.001). Significantly different staining of PPARβ was observed in the epithelium and stroma of benign and borderline tumours compared with grades 1, 2 and 3 tumours (χ2=11.28, d.f.=4, P<0.05; χ2=16.15, d.f.=4, P<0.005). In contrast, PDK1 immunostaining was absent in 9 out of 10 normal ovaries. Weak staining for PDK1 was observed in one normal ovary and 40% of benign ovarian tumours. All borderline and malignant ovarian tumours showed positive cytoplasmic and membrane PDK1 staining. Staining of PDK1 was confined to the epithelium and the blood vessels, and no apparent staining of the stroma was evident. Significantly different PDK1 staining was observed between the benign/borderline and malignant ovarian tumours (χ2=22.45, d.f.=5, P<0.001). In some borderline and high-grade tumours, staining of the reactive stroma was also evident. Our results suggest that unlike the colon, the endometrial, head and neck carcinomas, overexpression of PPARβ does not occur in ovarian tumours. However, overexpression of PDK1 was evident in borderline and low- to high-grade ovarian tumours and is consistent with its known role in tumorigenesis

Effects of intervention with sulindac and inulin/VSL#3 on mucosal and luminal factors in the pouch of patients with familial adenomatous polyposis

Contains fulltext : 97862.pdf (publisher's version ) (Open Access)BACKGROUND/AIM: In order to define future chemoprevention strategies for adenomas or carcinomas in the pouch of patients with familial adenomatous polyposis (FAP), a 4-weeks intervention with (1) sulindac, (2) inulin/VSL#3, and (3) sulindac/inulin/VSL#3 was performed on 17 patients with FAP in a single center intervention study. Primary endpoints were the risk parameters cell proliferation and glutathione S-transferase (GST) detoxification capacity in the pouch mucosa; secondary endpoints were the short chain fatty acid (SCFA) contents, pH, and cytotoxicity of fecal water. METHODS: Before the start and at the end of each 4-week intervention period, six biopsies of the pouch were taken and feces was collected during 24 h. Cell proliferation and GST enzyme activity was assessed in the biopsies and pH, SCFA contents, and cytotoxicity were assessed in the fecal water fraction. The three interventions (sulindac, inulin/VSL#3, sulindac/inulin/VSL#3) were compared with the Mann-Whitney U test. RESULTS: Cell proliferation was lower after sulindac or VSL#3/inulin, the combination treatment with sulindac/inulin/VSL#3 showed the opposite. GST enzyme activity was increased after sulindac or VSL#3/inulin, the combination treatment showed the opposite effect. However, no significance was reached in all these measures. Cytotoxicity, pH, and SCFA content of fecal water showed no differences at all among the three treatment groups. CONCLUSION: Our study revealed non-significant decreased cell proliferation and increased detoxification capacity after treatment with sulindac or VSL#3/inulin; however, combining both regimens did not show an additional effect

Pharmacological targeting of MTHFD2 suppresses acute myeloid leukemia by inducing thymidine depletion and replication stress

The folate metabolism enzyme MTHFD2 (methylenetetrahydrofolate dehydrogenase/cyclohydrolase) is consistently overexpressed in cancer but its roles are not fully characterized, and current candidate inhibitors have limited potency for clinical development. In the present study, we demonstrate a role for MTHFD2 in DNA replication and genomic stability in cancer cells, and perform a drug screen to identify potent and selective nanomolar MTHFD2 inhibitors; protein cocrystal structures demonstrated binding to the active site of MTHFD2 and target engagement. MTHFD2 inhibitors reduced replication fork speed and induced replication stress followed by S-phase arrest and apoptosis of acute myeloid leukemia cells in vitro and in vivo, with a therapeutic window spanning four orders of magnitude compared with nontumorigenic cells. Mechanistically, MTHFD2 inhibitors prevented thymidine production leading to misincorporation of uracil into DNA and replication stress. Overall, these results demonstrate a functional link between MTHFD2-dependent cancer metabolism and replication stress that can be exploited therapeutically with this new class of inhibitors

Toxicological aspects of bile acids and human fecal water on cultered human colon carcinoma cells

Colorectal tumorigenesis involves activation of mutations in proto-oncogenes, such as ras and c-myc, as well as mutations that inactivate tumor suppressor genes including the APC and the p53 gene. These genetic events, in turn, lead to epigenetic changes in signal transduction pathways, which regulate processes such as cell proliferation, differentiation and apoptosis. There exists also a large body of evidence from animal carcinogenesis studies and human epidemiology that a high fat intake drastically affects tumor incidence in the colon. However, there has been little understanding of how the dietary factors and genetic/epigentic events interact. It is, generally believed that this interaction is at least in part mediated by events occurring in the lumen of the large bowel. Bile acids have been suggested to mediate the tumor promoter effect of a high fat diet. The mechanism of bile acid induced tumor promoter activity is poorly understood. The aim of this thesis was to understand more about bile acids cellular effects, in the context of their tumor promoter activity, and to study the mechanisms behind the observed effects. By using cultured human colonic cell lines, we showed that dihydroxy bile acids induced the transcription factor AP-1, while other luminal components like cholesterol and long-chain fatty acids were without effect. The bile acid, deoxycholic acid (DCA) induced cell proliferation at the same concentrations as it induced AP-1. Incubation of the extracellular fluid of feces (human fecal water), which is the stool water in contact with the epithelial cells in vivo, resulted in activation of AP-1 and induction of cell proliferation which varied between different samples. Our attention then moved to, COX-2, another early response gene which has been shown to play an important role in colon tumorigenesis. We showed that dihydroxy bile acids and human fecal waters induced COX-2 promoter activity. This resulted in an increase in COX-2 protein expression. Interestingly, the concentrations of DCA that induced highest COX- 2 expression were cytotoxic. This led us to further studies on cell death induced by bile acids. We showed that bile acids induced apoptosis in the colonic cells, in a dose and time dependent fashion. Many substances which induce apoptosis are DNA damaging agents, which led us to test if DCA induced DNA damage. We observed that shortly after exposure of cells to DCA, damage to DNA occurred. The result of this damage is activation of the apoptosis program, which results for most cells in death. However, the few cells surviving the induced apoptosis showed low levels of caspase-3 and increased activity of NF-kB and AP-1 driven reporters, as well as an increase in COX-2 promoter activity. Mapping the region of the COX-2 promoter responsible for the effect, showed that both CRE and NF-kb as well as to some extent C/EBP elements are needed for full activation of the COX-2 promoter by DCA. In a follow up study, we characterized further the genotoxic effect of bile acids, and observed dose-dependent increase of DNA damage from DCA and lithocholic acid at concentrations above 300 µM. Testing 35 human fecal water samples, showed that 30% had very high potential to induce damage in intact cells while 50% had no effect. Finally, in a human dietary intervention study, we shifted the diet of healthy volunteers from a dairy product rich to a dairy product free diet, and monitored cytotoxicity and genotoxicity of their fecal waters. The result showed that when participants went off dairy products, the cytotoxicity of their fecal waters increased significantly, while there was no change observed for the genotoxicity of fecal waters. In summary, our results have contributed to the understanding of the molecular mechanisms by which bile acids influence tumorigenesis in the colon

Interactive 360-degrees video : User experience, user interface and heads-up display for educational training scenarios in nursing education

This thesis explores the user experience, potential and design principles of a HUD-based user interface in combination with interactive 360-degrees videos in nursing education. A HUD-based 360-degrees video was designed around a previously recorded scenario in an emergency room and user tests were conducted on nurse educators, working nurses and a nurse student.  Data from the user tests were gathered both through observations and interviews. The results show that participants' experience was overall positive and that the technology is seen as a realistic, interesting and valuable way to educate nursing students. Although no definitive design principles could be established for interactive 360-degrees videos, the result suggests that focusing on key design principles for multimedia learning may provide a better user experience. These principles include managing extraneous, essential and generative processing.Detta examensarbete utforskar användarupplevelsen,potentialen och begränsningarna avett HUD-baserat användargränssnitt i kombination med interaktiva 360-graders videos inom sjuksköterskeutbildning. Detta gjordes genom att designa och utveckla en HUD-baserad 360-graders video och utföra användar tester på lärare inom sjuksköterskeutbildning, arbetande sjuksköterskor och en sjuksköterskestudent. Data från användartester samlades in genom observationer samt intervjuer. Resultatet visar att deltagarnas upplevelse överlag var positiv och tekniken ses som ett intressant och fördelaktigt sätt att undervisa sjuksköterskestudenter. Resultatet tyder också på att fokus på designprinciper inom multimedielärande kan bidra med en bättre användarupplevelse

Interactive 360-degrees video : User experience, user interface and heads-up display for educational training scenarios in nursing education

This thesis explores the user experience, potential and design principles of a HUD-based user interface in combination with interactive 360-degrees videos in nursing education. A HUD-based 360-degrees video was designed around a previously recorded scenario in an emergency room and user tests were conducted on nurse educators, working nurses and a nurse student.  Data from the user tests were gathered both through observations and interviews. The results show that participants' experience was overall positive and that the technology is seen as a realistic, interesting and valuable way to educate nursing students. Although no definitive design principles could be established for interactive 360-degrees videos, the result suggests that focusing on key design principles for multimedia learning may provide a better user experience. These principles include managing extraneous, essential and generative processing.Detta examensarbete utforskar användarupplevelsen,potentialen och begränsningarna avett HUD-baserat användargränssnitt i kombination med interaktiva 360-graders videos inom sjuksköterskeutbildning. Detta gjordes genom att designa och utveckla en HUD-baserad 360-graders video och utföra användar tester på lärare inom sjuksköterskeutbildning, arbetande sjuksköterskor och en sjuksköterskestudent. Data från användartester samlades in genom observationer samt intervjuer. Resultatet visar att deltagarnas upplevelse överlag var positiv och tekniken ses som ett intressant och fördelaktigt sätt att undervisa sjuksköterskestudenter. Resultatet tyder också på att fokus på designprinciper inom multimedielärande kan bidra med en bättre användarupplevelse