Multidisciplinary, evidence-based guidelines for quality assurance in colorectal cancer screening and diagnosis have been developed by experts in a project coordinated by the International Agency for ...Research on Cancer. The full guideline document covers the entire process of population-based screening. It consists of 10 chapters and over 250 recommendations, graded according to the strength of the recommendation and the supporting evidence. The 450-page guidelines and the extensive evidence base have been published by the European Commission. The chapter on colonoscopic surveillance following adenoma removal includes 24 graded recommendations. The content of the chapter is presented here to promote international discussion and collaboration by making the principles and standards recommended in the new EU Guidelines known to a wider professional and scientific community. Following these recommendations has the potential to enhance the control of colorectal cancer through improvement in the quality and effectiveness of surveillance and other elements in the screening process, including multi-disciplinary diagnosis and management of the disease.
Hepatocellular carcinoma (HCC) growth relies on angiogenesis via vascular endothelial growth factor (VEGF) release. Hypoxia within tumour environment leads to intracellular stabilisation of hypoxia ...inducible factor 1 alpha (Hif1α) and signal transducer and activator of transcription (STAT3). Melatonin induces apoptosis in HCC, and shows anti-angiogenic features in several tumours. In this study, we used human HepG2 liver cancer cells as an in vitro model to investigate the anti-angiogenic effects of melatonin.
HepG2 cells were treated with melatonin under normoxic or CoCl2-induced hypoxia. Gene expression was analysed by RT-qPCR and western blot. Melatonin-induced anti-angiogenic activity was confirmed by in vivo human umbilical vein endothelial cells (HUVECs) tube formation assay. Secreted VEGF was measured by ELISA. Immunofluorescence was performed to analyse Hif1α cellular localisation. Physical interaction between Hif1α and its co-activators was analysed by immunoprecipitation and chromatin immunoprecipitation (ChIP).
Melatonin at a pharmacological concentration (1 mM) decreases cellular and secreted VEGF levels, and prevents HUVECs tube formation under hypoxia, associated with a reduction in Hif1α protein expression, nuclear localisation, and transcriptional activity. While hypoxia increases phospho-STAT3, Hif1α, and CBP/p300 recruitment as a transcriptional complex within the VEGF promoter, melatonin 1 mM decreases their physical interaction. Melatonin and the selective STAT3 inhibitor Stattic show a synergic effect on Hif1α, STAT3, and VEGF expression.
Melatonin exerts an anti-angiogenic activity in HepG2 cells by interfering with the transcriptional activation of VEGF, via Hif1α and STAT3. Our results provide evidence to consider this indole as a powerful anti-angiogenic agent for HCC treatment.
Population-based screening for early detection and treatment of colorectal cancer (CRC) and precursor lesions, using evidence-based methods, can be effective in populations with a significant burden ...of the disease provided the services are of high quality. Multidisciplinary, evidence-based guidelines for quality assurance in CRC screening and diagnosis have been developed by experts in a project co-financed by the European Union. The 450-page guidelines were published in book format by the European Commission in 2010. They include 10 chapters and over 250 recommendations, individually graded according to the strength of the recommendation and the supporting evidence. Adoption of the recommendations can improve and maintain the quality and effectiveness of an entire screening process, including identification and invitation of the target population, diagnosis and management of the disease and appropriate surveillance in people with detected lesions. To make the principles, recommendations and standards in the guidelines known to a wider professional and scientific community and to facilitate their use in the scientific literature, the original content is presented in journal format in an open-access Supplement of
Endoscopy.
The editors have prepared the present overview to inform readers of the comprehensive scope and content of the guidelines.
Abstract
Colorectal cancer (CRC) is a complex disease that can be caused by a spectrum of genetic variants ranging from low to high penetrance changes, that interact with the environment to determine ...which individuals will develop the disease. In this study, we sequenced 20 early-onset CRC patients to discover novel genetic variants that could be linked to the prompt disease development. Eight genes,
CHAD
,
CHD1L
,
ERCC6
,
IGTB7
,
PTPN13
,
SPATA20
,
TDG
and
TGS1,
were selected and re-sequenced in a further 304 early onset CRC patients to search for rare, high-impact variants. Although we found a recurring truncating variant in the
TDG
gene shared by two independent patients, the results obtained did not help consolidate any of the candidates as promising CRC predisposing genes. However, we found that potential risk alleles in our extended list of candidate variants have a tendency to appear at higher numbers in younger cases. This supports the idea that CRC onset may be oligogenic in nature and may show molecular heterogeneity. Further, larger and robust studies are thus needed to unravel the genetics behind early-onset CRC development, coupled with novel functional analyses and omic approaches that may offer complementary insight.
Aim: Some retrospective studies have shown a lack of benefit of 5-fluorouracil (5-FU) adjuvant chemotherapy in patients with mismatch repair (MMR) deficient colorectal cancer. Our aim was to assess ...if this molecular marker can predict benefit from 5-FU adjuvant chemotherapy. A second objective was to determine if MMR status influences short term survival. Methods: We included 754 patients with a median follow up of 728.5 days (range 1–1097). A total of 260 patients with stage II or III tumours received 5-FU adjuvant chemotherapy, according to standard clinical criteria and irrespective of their MMR status. A tumour was considered MMR deficient when either BAT-26 showed instability or there was loss of MLH1 or MSH2 protein expression. Results: At the end of the follow up period, 206 patients died and 120 presented with tumour recurrence. Sixty six (8.8%) patients had MMR deficient tumours. There were no significant differences in overall survival (MMR competent 72.1%; MMR deficient 78.8%; p = 0.3) or disease free survival (MMR competent 61.3%; MMR deficient 72.3%; p = 0.08). In patients with stage II and III tumours, benefit from 5-FU adjuvant chemotherapy was restricted to patients with MMR competent tumours (overall survival: chemotherapy 87.1%; non-chemotherapy 73.5%; log rank, p = 0.00001). Patients with MMR deficient tumours did not benefit from adjuvant chemotherapy (overall survival: chemotherapy 89.5%; non-chemotherapy 82.4%; log rank, p = 0.4). Conclusions: Benefit from 5-FU adjuvant chemotherapy depends on the MMR status of tumours in patients with colorectal cancer. 5-FU adjuvant chemotherapy improves survival in patients with MMR competent tumours but this benefit from chemotherapy cannot be extended to patients with MMR deficient tumours.
Stage II colon cancer (CC) still remains a clinical challenge with patient stratification for adjuvant therapy (AT) largely relying on clinical parameters. Prognostic biomarkers are urgently needed ...for better stratification. Previously, we have shown that WNT target genes AXIN2, DKK1, APCDD1, ASCL2 and LGR5 are silenced by DNA methylation and could serve as prognostic markers in stage II CC patients using methylation-specific PCR. Here, we have extended our discovery cohort AMC90-AJCC-II (N=65) and methylation was analyzed by quantitative pyrosequencing. Subsequently, we validated the results in an independent EPICOLON1 CC cohort (N=79). Methylation of WNT target genes is negatively correlated to mRNA expression. A combination of AXIN2 and DKK1 methylation significantly predicted recurrences in univariate (area under the curve (AUC)=0.83, confidence interval (CI): 0.72-0.94, P<0.0001) analysis in stage II microsatellite stable (MSS) CC patients. This two marker combination showed an AUC of 0.80 (CI: 0.68-0.91, P<0.0001) in the EPICOLON1 validation cohort. Multivariate analysis in the Academic Medical Center (AMC) cohort revealed that both WNT target gene methylation and consensus molecular subtype 4 (CMS4) are significantly associated with poor recurrence-free survival (hazard ratio (HR)
: 3.84, 95% CI: 1.14-12.43; HR
: 3.73, 95% CI: 1.22-11.48). CMS4 subtype tumors with WNT target methylation showed worse prognosis. Combining WNT target gene methylation and CMS4 subtype lead to an AUC of 0.89 (0.791-0.982, P<0.0001) for recurrence prediction. Notably, we observed that methylation of DKK1 is high in BRAF mutant and CIMP (CpG island methylator phenotype)-positive cancers, whereas AXIN2 methylation appears to be associated with CMS4. Methylation of AXIN2 and DKK1 were found to be robust markers for recurrence prediction in stage II MSS CC patients. Further validation of these findings in a randomized and prospective manner could pave a way to identify poor prognosis patients of stage II CC for AT.
Summary
Background
Histone deacetylases (HDACs) play a key role in signaling in many cell types. However, little is known about the participation of HDACs, particularly sirtuins (SIRTs), in platelet ...reactivity.
Objective
To investigate the role of HDACs in platelets, we examined the effects of SIRT inhibition on platelet function and protein acetylation in human platelets.
Methods
We used washed platelets obtained from healthy subjects. Cambinol (SIRT1 and SIRT2 inhibitor), AGK2 (specific SIRT2 inhibitor) and EX527 (specific SIRT1 inhibitor) were used as SIRT inhibitors. Platelets were stimulated with collagen, thrombin, or U46619, and platelet responses were determined according to optical aggregometry findings, dense granule release, and cytosolic calcium levels (Fura‐2AM fluorescence). Protein acetylation and phosphorylation were assessed by immunoblotting.
Results
SIRT inhibition remarkably reduced platelet responses (aggregation, granule release, and cytosolic calcium level; P < 0.05). SIRT2 was present in platelets at the level of mRNA and protein, and its specific inhibition reduced platelet responses. The acetylated protein pattern observed in resting platelets changed during platelet aggregation. Inhibition of SIRT2 increased the acetylation of Akt kinase, which in turn blocked agonist‐induced Akt phosphorylation and glycogen synthase kinase‐3β phosphorylation, which are markers of Akt activity. Finally, collagen‐induced aggregation provoked Akt acetylation.
Conclusions
Regulation of protein acetylation by SIRT2 plays a central role in platelet function. The effects of SIRT2 are mediated in part by the acetylation and inhibition of Akt. These results open a new avenue for research into the control of platelet function, and may help to identify new therapeutic targets.
Different types of hepatic tissue, including whole or split livers from organ donors or waste liver from therapeutic liver resections, are used to prepare human hepatocyte cultures. Characteristics ...of liver samples from different origins (gender, age, healthy/pathological status, xenobiotic treatment) as sources of human hepatocytes are key factors which notably determine viability and functionality of hepatocytes. The characterisation of the CYP system can be assessed in terms of activity (using specific substrates/inhibitors), protein (antibody analysis) and molecular biology-based mRNA amplification techniques (PCR technology and DNA microarrays). It could reasonably be considered that human hepatocytes reflect the heterogeneity of CYP expression in human liver and is a suitable model for drug metabolism studies. Several key issues need to be addressed at the early stages of drug development to better select drug candidates (metabolic profile and rate, identification of CYPs involved, drug-drug interactions due to enzyme induction/inhibition). The metabolic stability and metabolite profile of new chemicals can be easily investigated by incubating the drugs with fully competent metabolic models like hepatocyte suspensions or 24 h-cultured hepatocytes. CYP inhibitory effects are usually screened in recombinant CYP enzymes or microsomes, however, the actual concentration of substrate and inhibitor available to the CYP enzyme depends on processes missing in subcellular models (transport mechanisms, cytosolic enzymes, binding to intracellular proteins). Since intact cells more closely reflect the environment to which drugs are exposed in the liver, cultured hepatocytes constitute a more predictive model for drug-drug interactions. Screening of CYP inducers cannot be done in microsomes as it requires a cellular system fully capable of expressing CYP genes. Primary hepatocytes are still the unique in vitro model for global examination of inductive potential of drugs (monitored as increases in mRNA content or activity).
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