Yeast ORC sumoylation status fine-tunes origin licensing.

Sumoylation is emerging as a posttranslation modification important for regulating chromosome duplication and stability. The origin recognition complex (ORC) that directs DNA replication initiation by loading the MCM replicative helicase onto origins is sumoylated in both yeast and human cells. However, the biological consequences of ORC sumoylation are unclear. Here we report the effects of hypersumoylation and hyposumoylation of yeast ORC on ORC activity and origin function using multiple approaches. ORC hypersumoylation preferentially reduced the function of a subset of early origins, while Orc2 hyposumoylation had an opposing effect. Mechanistically, ORC hypersumoylation reduced MCM loading in vitro and diminished MCM chromatin association in vivo. Either hypersumoylation or hyposumoylation of ORC resulted in genome instability and the dependence of yeast on other genome maintenance factors, providing evidence that appropriate ORC sumoylation levels are important for cell fitness. Thus, yeast ORC sumoylation status must be properly controlled to achieve optimal origin function across the genome and genome stability.

Post-licensing Specification of Eukaryotic Replication Origins by Facilitated Mcm2-7 Sliding along DNA.

Eukaryotic genomes are replicated from many origin sites that are licensed by the loading of the replicative DNA helicase, Mcm2-7. How eukaryotic origin positions are specified remains elusive. Here we show that, contrary to the bacterial paradigm, eukaryotic replication origins are not irrevocably defined by selection of the helicase loading site, but can shift in position after helicase loading. Using purified proteins we show that DNA translocases, including RNA polymerase, can push budding yeast Mcm2-7 double hexamers along DNA. Displaced Mcm2-7 double hexamers support DNA replication initiation distal to the loading site in vitro. Similarly, in yeast cells that are defective for transcription termination, collisions with RNA polymerase induce a redistribution of Mcm2-7 complexes along the chromosomes, resulting in a corresponding shift in DNA replication initiation sites. These results reveal a eukaryotic origin specification mechanism that departs from the classical replicon model, helping eukaryotic cells to negotiate transcription-replication conflict.

Molecular mechanisms of tumour budding and its association with microenvironment in colorectal cancer.

Colorectal cancer (CRC) is the third most common cancer worldwide. Poor survival of CRC associated with the development of tumour metastasis led to the investigation of the potential biomarkers to predict outcomes in CRC patients. Tumour budding (TB) is a well-known independent prognostic marker for poor survival and disease metastasis. Therefore, it has been suggested that TB status is included in routine clinicopathological factors for risk assessment in CRC. In contrast with a vast majority of studies regarding the prognostic power of TB, there is no clear evidence pertaining to the underlying molecular mechanism driving this phenotype, or an understanding of TB relationship with the tumour microenvironment (TME). The aim of the present study is to present a comprehensive review of TB and tumour cell signalling pathways together with the cross-talk of immune cells that could drive TB formation in CRC.

Risk stratification for the detection of metachronous polyps after bowel screening polypectomy: clinical outcomes from the Integrated Technologies for Improved Polyp Surveillance (INCISE) study cohort.

BACKGROUND: After colorectal polypectomy, 20-50 per cent of patients develop metachronous polyps and some have increased colorectal cancer risk. British Society of Gastroenterology (BSG) 2020 guidelines recommend surveillance colonoscopy for high-risk patients based on index pathology. The aim of this study was to evaluate metachronous lesion outcome using BSG 2020 criteria. METHODS: A retrospective, multicentred study was conducted including patients who had polypectomy during screening colonoscopy (2009-2016) followed by surveillance. Demographics, index pathology, and BSG 2020 risk criteria were compared with regard to metachronous lesion pathology (non-advanced versus advanced lesions) and timing of detection (early versus late). Advanced lesions were defined as adenomas/serrated polyps greater than or equal to 10 mm, high-grade dysplasia, serrated polyps with dysplasia, or colorectal cancer, and late lesions those detected greater than 2 years after the index procedure. RESULTS: Of 3090 eligible patients, 2643 were included. Among these, retrospective BSG 2020 application would have excluded 51.5 per cent from surveillance. After a median of 36 months, the advanced polyp/colorectal cancer rate in BSG 2020 high-risk patients was 16.3 versus 13.0 per cent in low-risk patients. Older age (P = 0.008) correlated with advanced metachronous lesions. Male sex, greater than five polyps, and BSG 2020 high-risk criteria correlated with non-advanced and advanced lesions (P < 0.001). Older age (P < 0.001), villous features (P = 0.006), advanced index polyp (P = 0.020), and greater than five polyps (P < 0.001) correlated with early metachronous lesions. Male sex and BSG 2020 high-risk criteria correlated with early and late lesions (P < 0.001). On multivariable regression, increased polyp number (odds ratio (OR) 1.15 (95 per cent c.i. 1.07 to 1.25); P < 0.001) and villous features (OR 1.49 (95 per cent c.i. 1.05 to 2.10); P = 0.025) independently correlated with early advanced lesions. The rate of non-advanced and advanced metachronous polyps was higher in BSG 2020 high- versus low-risk patients (44.4 versus 35.4 per cent for non-advanced and 15.7 versus 11.8 per cent for advanced; P < 0.001), but the colorectal cancer rate was similar (0.6 versus 1.2 per cent). However, when examining only lesions detected greater than 2 years after the index colonoscopy in high- versus low-risk patients, no significant differences were observed (P = 0.140). CONCLUSION: BSG 2020 criteria correlated with metachronous polyps, but did not differentiate advanced and non-advanced lesions and were not predictive of late lesions.

Protein expression of S100A2 reveals it association with patient prognosis and immune infiltration profile in colorectal cancer.

PURPOSE: Colorectal cancer (CRC) is the third most diagnosed cancer worldwide. Despite a well-established knowledge of tumour development, biomarkers to predict patient outcomes are still required. S100 calcium-binding protein A2 (S100A2) has been purposed as a potential marker in many types of cancer, however, the prognostic value of S100A2 in CRC is rarely reported. MATERIAL AND METHODS: In this study, immunohistochemistry (IHC) was performed to identify the prognostic role of S100A2 protein expression in the tumour core of the tissue microarrays (TMAs) in colorectal cancer patients (n=787). Bulk RNA transcriptomic data was used to identify significant genes compared between low and high cytoplasmic S100A2 groups. Multiplex immunofluorescence (mIF) was performed to further study and confirm the immune infiltration in tumours with low and high cytoplasmic S100A2. RESULTS: Low cytoplasmic protein expression of S100A2 in the tumour core was associated with poor survival (HR 0.539, 95%CI 0.394-0.737, P<0.001) and other adverse tumour phenotypes. RNA transcriptomic analysis showed a gene significantly associated with the low cytoplasmic S100A2 group (AKT3, TAGLN, MYLK, FGD6 and ETFDH), which correlated with tumour development and progression. GSEA analysis identifies the enriched anti-tumour and immune activity group of genes in high cytoplasmic S100A2. Additionally, mIF staining showed that high CD3+FOXP3+ and CD163+ inversely associated with low cytoplasmic S100A2 (P<0.001, P=0.009 respectively). CONCLUSION: Our finding demonstrates a prognostic value of S100A2 together with the correlation with immune infiltration in CRC.

Novel Methods of Risk Stratifying Patients for Metachronous, Pre-Malignant Colorectal Polyps: A Systematic Review.

INTRODUCTION: Despite conventional measures of future polyp risk (histology, dysplasia, size, number), surveillance places a burden on patients and colonoscopy services. We aimed to review novel risk stratification techniques. METHODS: A systematic literature review was performed for studies using genomics, transcriptomics, IHC or microbiome as markers of metachronous polyp risk. RESULTS: 4165 papers underwent title, 303 abstract and 215 full paper review. 25 papers were included. 49 mutations/ SNPs/ haplotypes in 23 genes/ chromosomal regions (KRAS, APC, EGFR, COX1/2, IL23R, DRD2, CYP2C9/24A1/7A1, UGT1A6, ODC, ALOX12/15, PGDH, SRC, IGSF5, KCNS3, EPHB1/ KY, FAM188b, 3p24.1, 9q33.2, 13q33.2) correlated with metachronous adenoma / advanced adenoma risk. Expression levels of 6 proteins correlated with metachronous adenoma (p53, ß-catenin, COX2, Adnab-9, ALDH1A1) or sessile serrated polyp (ANXA10) risk. CONCLUSION: Although genomic and IHC markers correlated with metachronous polyp risk, it seems likely that a panel of novel markers will be required to refine this risk.

Mental Capacity Act (Northern Ireland) 2016.

Mental health legislation in Northern Ireland has always been separate from legislation in the rest of the UK; the Mental Health (Northern Ireland) Order (MHO) had been in place since 1986. In common with other jurisdictions, this legislation utilises the presence of mental disorder and risk as criteria for detention and involuntary treatment. The MHO has been replaced by the Mental Capacity Act (Northern Ireland) 2016 (MCA), an example of 'fusion' legislation in which impairment of decision-making capacity and best interests are the only criteria to be used when making decisions across health and social care. In this paper, we outline the development of the MCA to date, and discuss its potential to improve mental healthcare by placing the treatment of mental illness within the same legislative framework as physical illnesses.

A double-blind, placebo-controlled trial of sertraline for depressive symptoms in patients with stable, chronic schizophrenia.

There have been no studies specifically examining the efficacy of selective serotonin reuptake inhibitor antidepressants for the symptoms of depression in schizophrenia. This study aimed to determine the efficacy and safety of sertraline as a treatment for depressive symptoms in patients with stable, chronic schizophrenia. The Beck Depression Inventory (BDI) was used as the principal outcome measure and other measures of depressive symptoms as secondary outcome measures. Twenty-six patients were entered into a double-blind, placebo-controlled, 8-week trial of sertraline and were included in the intent-to-treat (ITT) analysis (13 in each group). Eight patients in the sertraline group and 12 in the placebo group completed at least four weeks in the study and were considered to have had adequate treatment. On the ITT analysis, the mean score on the BDI fell 14.5% for the sertraline group and 5.6% for the placebo group (p > 0.05); the mean score on the Hamilton Depression Rating Scale (HDRS) fell 16.99% for the sertraline group and 8.3% for the placebo group (p > 0.05). When the analysis was repeated for those who had received adequate treatment, the mean BDI score fell by 28% for the sertraline group and 6% for the placebo group (p = 0.1); the mean HDRS score fell 31% for the sertraline group and 8.6% for the placebo group (p = 0.02). On the Clinical Global Impression-Improvement Scale, 10 of the 13 patients on sertraline improved against four of the 13 in the placebo group (p = 0.05). Sertraline-treated patients showed a significant improvement on the anxiety/ depression subscale of the BPRS on ITT analysis (F = 10.1, p = 0.004). There was no significant effect on negative or positive symptoms. Sertraline was well tolerated. The results suggest that sertraline is useful as a treatment for depressive symptoms in schizophrenia.