Yes-associated protein 1 (YAP1) is a multifunctional protein that can interact with different transcription factors to activate gene expression. The role of YAP1 in tumorigenesis is unclear. We aimed ...to investigate the functional role of YAP1 in tumorigenesis of gastric cancer.
YAP1 expression in gastric adenocarcinoma was evaluated. The biological function was determined by proliferation assay, colony formation, cell invasion, and flow cytometric analysis through knocking down or ectopic expressing YAP1 in gastric cancer cell lines coupled with in vivo study. The possible downstream effectors of YAP1 were investigated by expression microarray.
YAP1 protein expression was upregulated in gastric cancer. Nuclear accumulation of YAP1 was associated with poor disease-specific survival (P = 0.021), especially in patients with early-stage diseases (P < 0.001). Knockdown YAP1 resulted in a significant reduction in proliferation, anchorage-dependent colony formation, cell invasion, and cell motility. Ectopic YAP1 expression promoted anchorage-independent colony formation, induced a more invasive phenotype, and accelerated cell growth both in vitro and in vivo. Microarray analysis highlighted the alteration of MAPK (mitogen-activated protein kinase) pathway by YAP1. We confirmed a constitutive activation of RAF/MEK/ERK (extracellular signal-regulated kinase) in YAP1-expressing MKN45 cells and further showed that YAP1 enhanced serum/epidermal growth factor-induced c-Fos expression in gastric cancer cells.
Our findings supported that YAP1 exhibits oncogenic property in gastric cancer. We provided the first evidence that YAP1 exerted the oncogenic function by enhancing the capacity to activate the early-response gene pathway. YAP1 could be a prognostic biomarker and potential therapeutic target for gastric cancer.
The rising incidence of inflammatory bowel disease in Asia supports the importance of environmental risk factors in disease aetiology. This prospective population-based case-control study in ...Asia-Pacific examined risk factors prior to patients developing IBD.
442 incident cases (186 Crohn's disease (CD); 256 UC; 374 Asians) diagnosed between 2011 and 2013 from eight countries in Asia and Australia and 940 controls (frequency-matched by sex, age and geographical location; 789 Asians) completed an environmental factor questionnaire at diagnosis. Unconditional logistic regression models were used to estimate adjusted ORs (aOR) and 95% CIs.
In multivariate model, being breast fed >12 months (aOR 0.10; 95% CI 0.04 to 0.30), antibiotic use (aOR 0.19; 0.07 to 0.52), having dogs (aOR 0.54; 0.35 to 0.83), daily tea consumption (aOR 0.62; 0.43 to 0.91) and daily physical activity (aOR 0.58; 0.35 to 0.96) decreased the odds for CD in Asians. In UC, being breast fed >12 months (aOR 0.16; 0.08 to 0.31), antibiotic use (aOR 0.48; 0.27 to 0.87), daily tea (aOR 0.63; 0.46 to 0.86) or coffee consumption (aOR 0.51; 0.36 to 0.72), presence of hot water tap (aOR 0.65; 0.46 to 0.91) and flush toilet in childhood (aOR 0.71; 0.51 to 0.98) were protective for UC development whereas ex-smoking (aOR 2.02; 1.22 to 3.35) increased the risk of UC.
This first population-based study of IBD risk factors in Asia-Pacific supports the importance of childhood immunological, hygiene and dietary factors in the development of IBD, suggesting that markers of altered intestinal microbiota may modulate risk of IBD later in life.
miR-18a is one of the most up-regulated miRNAs in colorectal cancers (CRC) based on miRNA profiling. In this study, we examined the functional significance of miR-18a in CRC.
Expression of miR-18a ...was investigated in 45 CRC patients. Potential target genes of miR-18a were predicted by in silico search and confirmed by luciferase activity assay and Western blot. DNA damage was measured by comet assay. Gene function was measured by cell viability, colony formation and apoptosis assays.
The up-regulation of miR-18a was validated and confirmed in 45 primary CRC tumors compared with adjacent normal tissues (p<0.0001). Through in silico search, the 3'UTR of Ataxia telangiectasia mutated (ATM) contains a conserved miR-18a binding site. Expression of ATM was down-regulated in CRC tumors (p<0.0001) and inversely correlated with miR-18a expression (r = -0.4562, p<0.01). Over-expression of miR-18a in colon cancer cells significantly reduced the luciferase activity of the construct with wild-type ATM 3'UTR but not that with mutant ATM 3'UTR, inferring a direct interaction of miR-18a with ATM 3'UTR. This was further confirmed by the down-regulation of ATM protein by miR-18a. As ATM is a key enzyme in DNA damage repair, we evaluated the effect of miR-18a on DNA double-strand breaks. Ectopic expression of miR-18a significantly inhibited the repair of DNA damage induced by etoposide (p<0.001), leading to accumulation of DNA damage, increase in cell apoptosis and poor clonogenic survival.
miR-18a attenuates cellular repair of DNA double-strand breaks by directly suppressing ATM, a key enzyme in DNA damage repair.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background:
Little is known of the clinical outcome of patients with older-onset inflammatory bowel disease IBD. We performed a systematic review to determine phenotype and outcomes of older-onset ...IBD compared with younger-onset subjects.
Methods:
A systematic search of Embase and Medline up to June 2015 identified studies investigating phenotype and outcomes of older-onset diagnosed at age ≥ 50 years Crohn’s disease CD and ulcerative colitis UC subjects. Pooled analyses of disease phenotype, medication use, and disease-related surgery were calculated.
Results:
We analysed findings from 43 studies comprising 8274 older-onset and 34641 younger-onset IBD subjects. Compared with younger-onset patients, older-onset CD patients were more likely to have colonic disease (odds ratio OR 2.56, 95% confidence interval CI 1.88 – 3.48) and inflammatory behaviour OR 1.19, 95% CI 1.07 – 1.33, and less likely to have penetrating disease or perianal involvement. More older-onset UC patients had left-sided colitis OR 1.49, 95% CI 1.18 – 1.88. Although fewer older-onset IBD patients received immunomodulators CD: OR 0.44; UC: OR 0.60 or biologicals CD: OR 0.34; UC: OR 0.41, older-onset CD was similar in the need for surgery OR 0.70, 95% CI 0.40 – 1.22 whereas more older-onset UC patients underwent surgery OR 1.36, 95% CI 1.18 – 1.57.
Conclusions:
Elderly IBD patients present with less complicated disease, but have similar or higher rates of surgery than non-elderly patients. Whether this reflects a non-benign disease course, physicians’ reluctance to employ immunomodulators, or both, merits further study which is essential for improving the care of IBD in the elderly.
Background & Aims Stool samples from patients with colorectal cancer (CRC) have a higher abundance of Peptostreptococcus anaerobius than stool from individuals without CRC, based on metagenome ...sequencing. We investigated whether P anaerobius contributes to colon tumor formation in mice and its possible mechanisms of carcinogenesis. Methods We performed quantitative polymerase chain reaction analyses to measure P anaerobius in 112 stool samples and 255 colon biopsies from patients with CRC or advanced adenoma and from healthy individuals (controls) undergoing colonoscopy examination at hospitals in Hong Kong and Beijing. C57BL/6 mice were given broad-spectrum antibiotics, followed by a single dose of azoxymethane, to induce colon tumor formation. Three days later, mice were given P anaerobius or Esherichia coli MG1655 (control bacteria), via gavage, for 6 weeks. Some mice were also given the reduced nicotinamide adenine dinucleotide phosphate oxidase inhibitor apocynin. Intestine tissues were collected and analyzed histologically. The colon epithelial cell line NCM460 and colon cancer cell lines HT-29 and Caco-2 were exposed to P anaerobius or control bacteria; cells were analyzed by immunoblot, proliferation, and bacterial attachment analyses and compared in gene expression profiling studies. Gene expression was knocked down in these cell lines with small interfering RNAs. Results P anaerobius was significantly enriched in stool samples from patients with CRC and in biopsies from patients with colorectal adenoma or CRC compared with controls. Mice depleted of bacteria and exposed to azoxymethane and P anaerobius had a higher incidence of intestinal dysplasia (63%) compared with mice not given the bacteria (8.3%; P < .01). P anaerobius mainly colonized the colon compared with the rest of the intestine. Colon cells exposed to P anaerobius had significantly higher levels of proliferation than control cells. We found genes that regulate cholesterol biosynthesis, Toll-like receptor (TLR) signaling, and AMP-activated protein kinase signaling to be significantly up-regulated in cells exposed to P anaerobius . Total cholesterol levels were significantly increased in colon cell lines exposed to P anaerobius via activation of sterol regulatory element-binding protein 2. P anaerobius interacted with TLR2 and TLR4 to increase intracellular levels of reactive oxidative species, which promoted cholesterol synthesis and cell proliferation. Depletion of reactive oxidative species by knockdown of TLR2 or TLR4, or incubation of cells with an antioxidant, prevented P anaerobius from inducing cholesterol biosynthesis and proliferation. Conclusions Levels of P anaerobius are increased in human colon tumor tissues and adenomas compared with non-tumor tissues; this bacteria increases colon dysplasia in a mouse model of CRC. P anaerobius interacts with TLR2 and TLR4 on colon cells to increase levels of reactive oxidative species, which promotes cholesterol synthesis and cell proliferation.
Altered gut microbiota is implicated in development of colorectal cancer (CRC). Some intestinal bacteria have been reported to potentiate intestinal carcinogenesis by producing genotoxins, altering ...the immune response and intestinal microenvironment, and activating oncogenic signaling pathways. We investigated whether stool from patients with CRC could directly induce colorectal carcinogenesis in mice.
We obtained stored stool samples from participants in a metagenome study performed in Hong Kong. Conventional (male C57BL/6) mice were given azoxymethane to induce colon neoplasia after receiving a course of antibiotics in drinking water. Mice were gavaged twice weekly with stool from 5 patients with CRC or 5 healthy individuals (controls) for 5 weeks. Germ-free C57BL/6 mice were gavaged once with stool from 5 patients with CRC or 5 controls. We collected intestinal tissues from mice and performed histology, immunohistochemistry, expression microarray, quantitative polymerase chain reaction, immunoblot, and flow cytometry analyses. We performed 16S ribosomal RNA gene sequencing analysis of feces from mice.
Significantly higher proportions of conventional mice fed with stool from individuals with CRC than control stool developed high-grade dysplasia (P < .05) and macroscopic polyps (P < .01). We observed a higher proportion of proliferating (Ki-67-positive) cells in colons of germ-free mice fed with stool from patients with CRC vs those fed with stool from controls (P < .05). Feces from germ-free and conventional mice fed with stool from patients with CRC vs controls contained different microbial compositions, with lower richness in mice fed with stool from patients with CRC. Intestines collected from conventional and germ-free mice fed with stool from patients with CRC had increased expression of cytokines that modulate inflammation, including C-X-C motif chemokine receptor 1, C-X-C motif chemokine receptor 2, interleukin 17A (IL17A), IL22, and IL23A. Intestines from conventional and germ-free mice fed with stool from patients with CRC contained higher proportions of T-helper 1 (Th1) cells (2.25% vs 0.44%) and Th17 cells (2.08% vs 0.31%) (P < .05 for each) than mice fed with stool from controls. Real-time polymerase chain reaction arrays revealed up-regulation of genes involved in cell proliferation, stemness, apoptosis, angiogenesis, invasiveness, and metastasis in mice fed with stool from patients with CRC.
We fed stool samples from patients with CRC and heathy individuals to germ-free mice and conventional mice with azoxymethane. We found stool from patients with CRC to increase the numbers of polyps, levels of intestinal dysplasia and proliferation, markers of inflammation, and proportions of Th1 and Th17 cells in colon, compared with stool from individuals without CRC. This study provides evidence that the fecal microbiota from patients with CRC can promote tumorigenesis in germ-free mice and mice given a carcinogen.
The underlining mechanisms of dietary cholesterol and nonalcoholic steatohepatitis (NASH) in contributing to hepatocellular carcinoma (HCC) remain undefined. Here we demonstrated that ...high-fat-non-cholesterol-fed mice developed simple steatosis, whilst high-fat-high-cholesterol-fed mice developed NASH. Moreover, dietary cholesterol induced larger and more numerous NASH-HCCs than non-cholesterol-induced steatosis-HCCs in diethylnitrosamine-treated mice. NASH-HCCs displayed significantly more aberrant gene expression-enriched signaling pathways and more non-synonymous somatic mutations than steatosis-HCCs (335 ± 84/sample vs 43 ± 13/sample). Integrated genetic and expressional alterations in NASH-HCCs affected distinct genes pertinent to five pathways: calcium, insulin, cell adhesion, axon guidance and metabolism. Some of the novel aberrant gene expression, mutations and core oncogenic pathways identified in cholesterol-associated NASH-HCCs in mice were confirmed in human NASH-HCCs, which included metabolism-related genes (ALDH18A1, CAD, CHKA, POLD4, PSPH and SQLE) and recurrently mutated genes (RYR1, MTOR, SDK1, CACNA1H and RYR2). These findings add insights into the link of cholesterol to NASH and NASH-HCC and provide potential therapeutic targets.
Pancreatic cancer induces a substantial global burden. We examined its global incidence/mortality rates and their correlation with socioeconomic development (Human Development Index HDI and Gross ...Domestic Product GDP in 2000 as proxy measures). Data on age-standardized incidence/mortality rates in 2012 were retrieved from the GLOBOCAN database. Temporal patterns in 1998-2007 were assessed for 39 countries according to gender. The Average Annual Percent Change (AAPC) of the incidence/mortality trends was evaluated using joinpoint regression analysis. The age-standardized incidence ranged between 0.8-8.9/100,000. When compared among countries, Brazil (AAPC = 10.4, 95%C.I. = 0.8,21) and France (AAPC = 4.7, 95%C.I. = 3.6,5.9) reported the highest incidence rise in men. The greatest increase in women was reported in Thailand (AAPC = 7, 95%C.I. = 2.1,12.1) and Ecuador (AAPC = 4.3, 95%C.I. = 1.3,7.3). For mortality, the Philippines (APCC = 4.3, 95%C.I. = 2,6.6) and Croatia (AAPC = 2, 95% C.I. = 0,3.9) reported the biggest increase among men. The Philippines (AAPC = 5.8, 95% C.I. 4.5,7.2) and Slovakia (AAPC = 3.1, 95% C.I. 0.9,5.3) showed the most prominent rise among women. Its incidence was positively correlated with HDI (men: r = 0.66; women: r = 0.70) and GDP (men: r = 0.29; women: r = 0.28, all p < 0.05), and similarly for mortality (men: r = 0.67; women: r = 0.72 HDI; men: r = 0.23; women: r = 0.28 GDP). In summary, the incidence and mortality of pancreatic cancer were rising in many countries, requiring regular surveillance.
Aims Post-infectious irritable bowel syndrome (PI-IBS) is a subset of IBS which occurs after an episode of acute gastrointestinal infections. The mechanisms of PI-IBS are not fully understood. ...Currently, numerous animal models have been used in the study of PI-IBS. This article reviews the strengths and weaknesses of these models. Methods All relevant articles were identified by searching in Ovid SP from 1962, the year the term PI-IBS was coined, up to December 31, 2009. The types of model were categorized as either post-infectious or post-inflammatory, and the characteristics of each kind of model were listed. Results Based on our literature search, 268 articles were identified. Of those articles, 50 were included in this review. The existing PI-IBS models include infection with bacteria (e.g., Campylobacter jejuni, Salmonella enterica, and Campylobacter rodentium), and infection with parasites (e.g., Trichinella spiralis, Nippostrongylus brasiliensis, and Cryptosporidium parvum). The post-inflammatory IBS models are commonly induced with chemical agents, such as acetic acid, deoxycholic acid, dextran sulfate sodium, mustard oil, zymosan, and trinitrobenzene sulfonic acid (TNBS). TNBS is the most commonly used agent for post-inflammatory IBS models, but the experimental protocol varies. These models have one or more aspects similar to IBS patients. Conclusions Different methods have been used for the development of post-infectious or post-inflammatory IBS models. Each model has its weaknesses and strengths. More studies are needed to establish post-infection IBS models using more common pathogens. A standard protocol in developing TNBS-induced post-inflammatory IBS model is needed.
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