RNF8 ubiquitylation of XRN2 facilitates R-loop resolution and restrains genomic instability in BRCA1 mutant cells

Breast cancer linked with BRCA1/2 mutations commonly recur and resist current therapies, including PARP inhibitors. Given the lack of effective targeted therapies for BRCA1-mutant cancers, we sought to identify novel targets to selectively kill these cancers. Here, we report that loss of RNF8 significantly protects Brca1-mutant mice against mammary tumorigenesis. RNF8 deficiency in human BRCA1-mutant breast cancer cells was found to promote R-loop accumulation and replication fork instability, leading to increased DNA damage, senescence, and synthetic lethality. Mechanistically, RNF8 interacts with XRN2, which is crucial for transcription termination and R-loop resolution. We report that RNF8 ubiquitylates XRN2 to facilitate its recruitment to R-loop-prone genomic loci and that RNF8 deficiency in BRCA1-mutant breast cancer cells decreases XRN2 occupancy at R-loop-prone sites, thereby promoting R-loop accumulation, transcription-replication collisions, excessive genomic instability, and cancer cell death. Collectively, our work identifies a synthetic lethal interaction between RNF8 and BRCA1, which is mediated by a pathological accumulation of R-loops

Causes of varicose vein recurrence: Late results of a randomized controlled trial of stripping the long saphenous vein

BackgroundThe purpose of this study was to investigate the long-term outcomes following stripping of the long saphenous vein during primary varicose vein surgery and to identify factors which may predict recurrence and the need for reoperation.MethodsThe original study was designed as a randomized trial of 100 patients (133 legs) who underwent saphenofemoral ligation with or without long saphenous vein stripping. After invitation 11 years later, 51 patients (74 legs) underwent clinical review and duplex imaging and completed an Aberdeen Varicose Vein Symptom Severity Score (AVVSSS). The hospital notes of the original cohort of patients were used to compile cumulative data and assess predictive factors.ResultsA cumulative total of 83 legs had developed clinically recurrent varicose veins by 11 years (62%). There was no statistically significant difference between the ligation-only and the stripping groups. Reoperation was required for 20 of 69 legs that underwent ligation alone compared with 7 of 64 legs that had additional long saphenous vein stripping (relative risk [RR], 2.65; 95% confidence interval, 1.20 to 5.84; P = .012). By life table analysis, freedom from reoperation at 11 years was 70% after ligation, compared with 86% after stripping (P = .01). The presence of neovascularization (RR, 2.88; P = .15) , an incompetent superficial vessel in the thigh (RR, 3.24; P = .03) or an incompetent saphenofemoral junction on duplex imaging at 2 years postoperatively (RR, 4.89; P = .0001) increased the risk of a patient's developing clinically recurrent veins. Patients with visible recurrent varicose veins had a significantly worse AVVSSS (P = .001).ConclusionStripping the long saphenous vein is recommended as part of routine varicose vein surgery as it reduced the risk of reoperation by 60% after 11 years, although it did not reduce the rate of visible recurrent veins

Consumers’ and health providers’ views and perceptions of partnering to improve health services design, delivery and evaluation: a co‐produced qualitative evidence synthesis

Background: Partnering with consumers in the planning, delivery and evaluation of health services is an essential component of person-centred care. There are many ways to partner with consumers to improve health services, including formal group partnerships (such as committees, boards or steering groups). However, consumers' and health providers' views and experiences of formal group partnerships remain unclear. In this qualitative evidence synthesis (QES), we focus specifically on formal group partnerships where health providers and consumers share decision-making about planning, delivering and/or evaluating health services. Formal group partnerships were selected because they are widely used throughout the world to improve person-centred care. For the purposes of this QES, the term 'consumer' refers to a person who is a patient, carer or community member who brings their perspective to health service partnerships. 'Health provider' refers to a person with a health policy, management, administrative or clinical role who participates in formal partnerships in an advisory or representative capacity. This QES was co-produced with a Stakeholder Panel of consumers and health providers. The QES was undertaken concurrently with a Cochrane intervention review entitled Effects of consumers and health providers working in partnership on health services planning, delivery and evaluation. Objectives: 1. To synthesise the views and experiences of consumers and health providers of formal partnership approaches that aimed to improve planning, delivery or evaluation of health services. 2. To identify best practice principles for formal partnership approaches in health services by understanding consumers' and health providers' views and experiences. Search methods: We searched MEDLINE, Embase, PsycINFO and CINAHL for studies published between January 2000 and October 2018. We also searched grey literature sources including websites of relevant research and policy organisations involved in promoting person-centred care. Selection criteria: We included qualitative studies that explored consumers' and health providers' perceptions and experiences of partnering in formal group formats to improve the planning, delivery or evaluation of health services. Data collection and analysis: Following completion of abstract and full-text screening, we used purposive sampling to select a sample of eligible studies that covered a range of pre-defined criteria, including rich data, range of countries and country income level, settings, participants, and types of partnership activities. A Framework Synthesis approach was used to synthesise the findings of the sample. We appraised the quality of each study using the CASP (Critical Appraisal Skill Program) tool. We assessed our confidence in the findings using the GRADE-CERQual (Confidence in the Evidence from Reviews of Qualitative research) approach. The Stakeholder Panel was involved in each stage of the review from development of the protocol to development of the best practice principles. Main results: We found 182 studies that were eligible for inclusion. From this group, we selected 33 studies to include in the final synthesis. These studies came from a wide range of countries including 28 from high-income countries and five from low- or middle-income countries (LMICs). Each of the studies included the experiences and views of consumers and/or health providers of partnering in formal group formats. The results were divided into the following categories. Contextual factors influencing partnerships: government policy, policy implementation processes and funding, as well as the organisational context of the health service, could facilitate or impede partnering (moderate level of confidence). Consumer recruitment: consumer recruitment occurred in different ways and consumers managed the recruitment process in a minority of studies only (high level of confidence). Recruiting a range of consumers who were reflective of the clinic's demographic population was considered desirable, particularly by health providers (high level of confidence). Some health providers perceived that individual consumers' experiences were not generalisable to the broader population whereas consumers perceived it could be problematic to aim to represent a broad range of community views (high level of confidence). Partnership dynamics and processes: positive interpersonal dynamics between health providers and consumers facilitated partnerships (high level of confidence). However, formal meeting formats and lack of clarity about the consumer role could constrain consumers’ involvement (high level of confidence). Health providers’ professional status, technical knowledge and use of jargon were intimidating for some consumers (high level of confidence) and consumers could feel their experiential knowledge was not valued (moderate level of confidence). Consumers could also become frustrated when health providers dominated the meeting agenda (moderate level of confidence) and when they experienced token involvement, such as a lack of decision-making power (high level of confidence). Perceived impacts on partnership participants: partnering could affect health provider and consumer participants in both positive and negative ways (high level of confidence). Perceived impacts on health service planning, delivery and evaluation: partnering was perceived to improve the person-centredness of health service culture (high level of confidence), improve the built environment of the health service (high level of confidence), improve health service design and delivery e.g. facilitate 'out of hours' services or treatment closer to home (high level of confidence), enhance community ownership of health services, particularly in LMICs (moderate level of confidence), and improve consumer involvement in strategic decision-making, under certain conditions (moderate level of confidence). There was limited evidence suggesting partnering may improve health service evaluation (very low level of confidence). Best practice principles for formal partnering to promote person-centred care were developed from these findings. The principles were developed collaboratively with the Stakeholder Panel and included leadership and health service culture; diversity; equity; mutual respect; shared vision and regular communication; shared agendas and decision-making; influence and sustainability. Authors' conclusions: Successful formal group partnerships with consumers require health providers to continually reflect and address power imbalances that may constrain consumers' participation. Such imbalances may be particularly acute in recruitment procedures, meeting structure and content and decision-making processes. Formal group partnerships were perceived to improve the physical environment of health services, the person-centredness of health service culture and health service design and delivery. Implementing the best practice principles may help to address power imbalances, strengthen formal partnering, improve the experiences of consumers and health providers and positively affect partnership outcomes.</p

Is technology acquisition enough to improve China's product quality? Evidence from firm-level panel data

As developing countries open themselves up to trade, many industrial firms in these countries are finding it difficult to compete internationally due to poor product quality and low product variety. Although China has been the largest producer of crude steel since 1996, China's steel firms have produced an overabundance of low-quality steel while domestic purchasers of steel have increasingly demanded higher quality steel products. Many have argued that for Chinese steel firms to improve product quality they must adopt more advanced technologies. Employing firm-level panel data of steel firms in China, we econometrically test the relative importance of two possible sets of factors affecting a firm's ability to utilize technology to improve product quality: technology acquisition factors and technology absorptive capacity factors. We find that technology complements such as in-house R&D and foreign knowledge must be combined with technology for Chinese firms to improve product quality.technological change, product quality, China,

CDK12 inhibition reduces abnormalities in cells from patients with myotonic dystrophy and in a mouse model

Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Myotonic dystrophy type 1 (DM1) is an RNA-based disease with no current treatment. It is caused by a transcribed CTG repeat expansion within the 3' untranslated region of the dystrophia myotonica protein kinase (DMPK) gene. Mutant repeat expansion transcripts remain in the nuclei of patients' cells, forming distinct microscopically detectable foci that contribute substantially to the pathophysiology of the condition. Here, we report small-molecule inhibitors that remove nuclear foci and have beneficial effects in the HSALR mouse model, reducing transgene expression, leading to improvements in myotonia, splicing, and centralized nuclei. Using chemoproteomics in combination with cell-based assays, we identify cyclin-dependent kinase 12 (CDK12) as a druggable target for this condition. CDK12 is a protein elevated in DM1 cell lines and patient muscle biopsies, and our results showed that its inhibition led to reduced expression of repeat expansion RNA. Some of the inhibitors identified in this study are currently the subject of clinical trials for other indications and provide valuable starting points for a drug development program in DM1

Bicaudal is a conserved substrate for Drosophila and mammalian caspases and is essential for cell survival

Members of the caspase family of cysteine proteases coordinate cell death through restricted proteolysis of diverse protein substrates and play a conserved role in apoptosis from nematodes to man. However, while numerous substrates for the mammalian cell death-associated caspases have now been described, few caspase substrates have been identified in other organisms. Here, we have utilized a proteomics-based approach to identify proteins that are cleaved by caspases during apoptosis in Drosophila D-Mel2 cells, a subline of the Schneider S2 cell line. This approach identified multiple novel substrates for the fly caspases and revealed that bicaudal/betaNAC is a conserved substrate for Drosophila and mammalian caspases. RNAi-mediated silencing of bicaudal expression in Drosophila D-Mel2 cells resulted in a block to proliferation, followed by spontaneous apoptosis. Similarly, silencing of expression of the mammalian bicaudal homologue, betaNAC, in HeLa, HEK293T, MCF-7 and MRC5 cells also resulted in spontaneous apoptosis. These data suggest that bicaudal/betaNAC is essential for cell survival and is a conserved target of caspases from flies to man