Investigating the role of CBX2 in models of triple negative breast cancer

Breast cancer accounts for around 11,500 deaths per year in the UK in women. There are several subtypes of breast cancer including triple negative breast cancer (TNBC) which is categorised by a lack of oestrogen, progesterone and human epidermal growth factor 2 (HER2) hormone receptor expression. The prognosis for patients with TNBC is poor as it is an aggressive subtype of the disease that currently lacks any targeted therapeutics and is therefore hard to treat. The identification of novel therapeutic targets for TNBC is therefore crucial.Epigenetics is the study of gene expression control via chemical modification of DNA and histone proteins. Recent studies have shown that altered histone modification is linked with cancer development. Epigenetic regulatory proteins may therefore be a source of novel therapeutic targets in cancer. CBX2 is an epigenetic reader protein and is part of the polycomb repressive complex 1 (PRC1). Expression of CBX2 is increased in TNBC compared to normal breast tissue indicating that it may play a role in the progression of this disease. This study aimed to investigate the function of CBX2 in TNBC by downregulating CBX2 expression in TNBC cell line models by RNA interference (RNAi) and analysing phenotypic and gene expression changes. We identified that CBX2 is present in an active phosphorylated form in TNBC cells and that cell proliferation decreased when CBX2 was knocked down. We identified that the expression of cell cycle regulatory genes such as Cyclin D1 (CCND1), CCND3, CCNA2 CDK1 and CDK4 decreased when CBX2 was knocked down and RNA-Seq analysis in TNBC cells following CBX2 knockdown showed that differentially expressed genes were associated with the cell cycle and multiple oncogenic signalling pathways. These results suggest that CBX2 may play a key role in TNBC development and may therefore be a potential future therapeutic target

Drivers and health implications of the dietary transition among Inuit in the Canadian Arctic : a scoping review

Objective: The current study undertook a systematic scoping review on the drivers and implications of dietary changes among Inuit in the Canadian Arctic. Design: A keyword search of peer-reviewed articles was performed using PubMed, Web of Science, CINAHL, Academic Search Premier, Circumpolar Health Bibliographic Database and High North Research Documents. Eligibility criteria included all full-text articles of any design reporting on research on food consumption, nutrient intake, dietary adequacy, dietary change, food security, nutrition-related chronic diseases or traditional food harvesting and consumption among Inuit populations residing in Canada. Articles reporting on in vivo and in vitro experiments or on health impacts of environmental contaminants were excluded. Results: A total of 162 studies were included. Studies indicated declining country food (CF) consumption in favour of market food (MF). Drivers of this transition include colonial processes, poverty and socio-economic factors, changing food preferences and knowledge, and climate change. Health implications of the dietary transition are complex. Micro-nutrient deficiencies and dietary inadequacy are serious concerns and likely exacerbated by increased consumption of non-nutrient dense MF. Food insecurity, overweight, obesity and related cardiometabolic health outcomes are growing public health concerns. Meanwhile, declining CF consumption is entangled with shifting culture and traditional knowledge, with potential implications for psychological, spiritual, social and cultural health and well-being. Conclusions: By exploring and synthesising published literature, this review provides insight into the complex factors influencing Inuit diet and health. Findings may be informative for future research, decision-making and intersectoral actions around risk assessment, food policy and innovative community programmes

Putting Food on The Table Project Toolkit

A toolkit to help community groups and members understand and address the food security needs of older adults in their community.https://source.sheridancollege.ca/centres_elder_food_toolkit/1000/thumbnail.jp

The Epigenetic Regulatory Protein CBX2 Promotes mTORC1 Signalling and Inhibits DREAM Complex Activity to Drive Breast Cancer Cell Growth

Chromobox 2 (CBX2) is a chromatin-binding component of polycomb repressive complex 1, which causes gene silencing. CBX2 expression is elevated in triple-negative breast cancer (TNBC), for which there are few therapeutic options. Here, we aimed to investigate the functional role of CBX2 in TNBC. CBX2 knockdown in TNBC models reduced cell numbers, which was rescued by ectopic expression of wild-type CBX2 but not a chromatin binding-deficient mutant. Blocking CBX2 chromatin interactions using the inhibitor SW2_152F also reduced cell growth, suggesting CBX2 chromatin binding is crucial for TNBC progression. RNA sequencing and gene set enrichment analysis of CBX2-depleted cells identified downregulation of oncogenic signalling pathways, including mTORC1 and E2F signalling. Subsequent analysis identified that CBX2 represses the expression of mTORC1 inhibitors and the tumour suppressor RBL2. RBL2 repression, in turn, inhibits DREAM complex activity. The DREAM complex inhibits E2F signalling, causing cell senescence; therefore, inhibition of the DREAM complex via CBX2 may be a key oncogenic driver. We observed similar effects in oestrogen receptor-positive breast cancer, and analysis of patient datasets suggested CBX2 inhibits RBL2 activity in other cancer types. Therapeutic inhibition of CBX2 could therefore repress mTORC1 activation and promote DREAM complex-mediated senescence in TNBC and could have similar effects in other cancer types

Development and replication of objective measurements of social visual engagement to aid in early diagnosis and assessment of autism

IMPORTANCE: Autism spectrum disorder is a common and early-emerging neurodevelopmental condition. While 80% of parents report having had concerns for their child\u27s development before age 2 years, many children are not diagnosed until ages 4 to 5 years or later. OBJECTIVE: To develop an objective performance-based tool to aid in early diagnosis and assessment of autism in children younger than 3 years. DESIGN, SETTING, AND PARTICIPANTS: In 2 prospective, consecutively enrolled, broad-spectrum, double-blind studies, we developed an objective eye-tracking-based index test for children aged 16 to 30 months, compared its performance with best-practice reference standard diagnosis of autism (discovery study), and then replicated findings in an independent sample (replication study). Discovery and replication studies were conducted in specialty centers for autism diagnosis and treatment. Reference standard diagnoses were made using best-practice standardized protocols by specialists blind to eye-tracking results. Eye-tracking tests were administered by staff blind to clinical results. Children were enrolled from April 27, 2013, until September 26, 2017. Data were analyzed from March 28, 2018, to January 3, 2019. MAIN OUTCOMES AND MEASURES: Prespecified primary end points were the sensitivity and specificity of the eye-tracking-based index test compared with the reference standard. Prespecified secondary end points measured convergent validity between eye-tracking-based indices and reference standard assessments of social disability, verbal ability, and nonverbal ability. RESULTS: Data were collected from 1089 children: 719 children (mean [SD] age, 22.4 [3.6] months) in the discovery study, and 370 children (mean [SD] age, 25.4 [6.0] months) in the replication study. In discovery, 224 (31.2%) were female and 495 (68.8%) male; in replication, 120 (32.4%) were female and 250 (67.6%) male. Based on reference standard expert clinical diagnosis, there were 386 participants (53.7%) with nonautism diagnoses and 333 (46.3%) with autism diagnoses in discovery, and 184 participants (49.7%) with nonautism diagnoses and 186 (50.3%) with autism diagnoses in replication. In the discovery study, the area under the receiver operating characteristic curve was 0.90 (95% CI, 0.88-0.92), sensitivity was 81.9% (95% CI, 77.3%-85.7%), and specificity was 89.9% (95% CI, 86.4%-92.5%). In the replication study, the area under the receiver operating characteristic curve was 0.89 (95% CI, 0.86-0.93), sensitivity was 80.6% (95% CI, 74.1%-85.7%), and specificity was 82.3% (95% CI, 76.1%-87.2%). Eye-tracking test results correlated with expert clinical assessments of children\u27s individual levels of ability, explaining 68.6% (95% CI, 58.3%-78.6%), 63.4% (95% CI, 47.9%-79.2%), and 49.0% (95% CI, 33.8%-65.4%) of variance in reference standard assessments of social disability, verbal ability, and nonverbal cognitive ability, respectively. CONCLUSIONS AND RELEVANCE: In two diagnostic studies of children younger than 3 years, objective eye-tracking-based measurements of social visual engagement quantified diagnostic status as well as individual levels of social disability, verbal ability, and nonverbal ability in autism. These findings suggest that objective measurements of social visual engagement can be used to aid in autism diagnosis and assessment

Incomplete inhibition of phosphorylation of 4E-BP1 as a mechanism of primary resistance to ATP-competitive mTOR inhibitors

The mammalian target of rapamycin (mTOR) regulates cell growth by integrating nutrient and growth factor signaling and is strongly implicated in cancer. But mTOR is not an oncogene, and which tumors will be resistant or sensitive to new ATP-competitive mTOR inhibitors now in clinical trials remains unknown. We screened a panel of over 600 human cancer cell lines to identify markers of resistance and sensitivity to the mTOR inhibitor PP242. RAS and PIK3CA mutations were the most significant genetic markers for resistance and sensitivity to PP242, respectively; colon origin was the most significant marker for resistance based on tissue type. Among colon cancer cell lines, those with KRAS mutations were most resistant to PP242, while those without KRAS mutations most sensitive. Surprisingly, cell lines with co-mutation of PIK3CA and KRAS had intermediate sensitivity. Immunoblot analysis of the signaling targets downstream of mTOR revealed that the degree of cellular growth inhibition induced by PP242 was correlated with inhibition of phosphorylation of the translational repressor 4E-BP1, but not ribosomal protein S6. In a tumor growth inhibition trial of PP242 in patient-derived colon cancer xenografts, resistance to PP242 induced inhibition of 4E-BP1 phosphorylation and xenograft growth was again observed in KRAS mutant tumors without PIK3CA co-mutation, compared to KRAS WT controls. We show that, in the absence of PIK3CA co-mutation, KRAS mutations are associated with resistance to PP242 and that this is specifically linked to changes in the level of phosphorylation of 4E-BP1