Gene copy-number changes and chromosomal instability induced by aneuploidy confer resistance to chemotherapy

Mitotic errors lead to aneuploidy, a condition of karyotype imbalance, frequently found in cancer cells. Alterations in chromosome copy number induce a wide variety of cellular stresses, including genome instability. Here, we show that cancer cells might exploit aneuploidy-induced genome instability and the resulting gene copy-number changes to survive under conditions of selective pressure, such as chemotherapy. Resistance to chemotherapeutic drugs was dictated by the acquisition of recurrent karyotypes, indicating that gene dosage might play a role in driving chemoresistance. Thus, our study establishes a causal link between aneuploidy-driven changes in gene copy number and chemoresistance and might explain why some chemotherapies fail to succeed

Aneuploidy renders cancer cells vulnerable to mitotic checkpoint inhibition

Selective targeting of aneuploid cells is an attractive strategy for cancer treatment(1). Here, we mapped the aneuploidy landscapes of ~1,000 human cancer cell lines, and analyzed genetic and chemical perturbation screens(2–9) to reveal aneuploidy-associated cellular vulnerabilities. We identified and validated an increased sensitivity of aneuploid cancer cells to genetic perturbation of core components of the spindle assembly checkpoint (SAC), which ensures the proper segregation of chromosomes during mitosis(10). Surprisingly, we also found aneuploid cancer cells to be less sensitive to short-term exposures to multiple SAC inhibitors. Indeed, aneuploid cancer cells became increasingly more sensitive to SAC inhibition (SACi) over time. Aneuploid cells exhibited aberrant spindle geometry and dynamics, and kept dividing in the presence of SACi, resulting in accumulating mitotic defects, and in unstable and less fit karyotypes. Therefore, although aneuploid cancer cells could overcome SACi more readily than diploid cells, their long-term proliferation was jeopardized. We identified a specific mitotic kinesin, KIF18A, whose activity was perturbed in aneuploid cancer cells. Aneuploid cancer cells were particularly vulnerable to KIF18A depletion, and KIF18A overexpression restored their response to SACi. Our study reveals a novel, therapeutically-relevant, synthetic lethal interaction between aneuploidy and the SAC

rs5888 Variant of SCARB1 Gene Is a Possible Susceptibility Factor for Age-Related Macular Degeneration

Major genetic factors for age-related macular degeneration (AMD) have recently been identified as susceptibility risk factors, including variants in the CFH gene and the ARMS2 LOC387715/HTRA1locus. Our purpose was to perform a case-control study in two populations among individuals who did not carry risk variants for CFHY402H and LOC387715 A69S (ARMS2), called “study” individuals, in order to identify new genetic risk factors. Based on a candidate gene approach, we analyzed SNP rs5888 of the SCARB1 gene, coding for SRBI, which is involved in the lipid and lutein pathways. This study was conducted in a French series of 1241 AMD patients and 297 controls, and in a North American series of 1257 patients with advanced AMD and 1732 controls. Among these individuals, we identified 61 French patients, 77 French controls, 85 North American patients and 338 North American controls who did not carry the CFH nor ARMS2 polymorphisms. An association between AMD and the SCARB1 gene was seen among the study subjects. The genotypic distribution of the rs5888 polymorphism was significantly different between cases and controls in the French population (p<0.006). Heterozygosity at the rs5888 SNP increased risk of AMD compared to the CC genotypes in the French study population (odds ratio (OR) = 3.5, CI95%: 1.4–8.9, p<0.01) and after pooling the 2 populations (OR = 2.9, 95% CI: 1.6–5.3, p<0.002). Subgroup analysis in exudative forms of AMD revealed a pooled OR of 3.6 for individuals heterozygous for rs5888 (95% CI: 1.7–7.6, p<0.0015). These results suggest the possible contribution of SCARB1, a new genetic factor in AMD, and implicate a role for cholesterol and antioxidant micronutrient (lutein and vitamin E) metabolism in AMD

Ophthalmology

PURPOSE: To investigate systemic and ocular determinants of peripapillary retinal nerve fiber layer thickness (pRNFLT) in the European population. DESIGN: Cross-sectional meta-analysis. PARTICIPANTS: A total of 16 084 European adults from 8 cohort studies (mean age range, 56.9+/-12.3-82.1+/-4.2 years) of the European Eye Epidemiology (E3) consortium. METHODS: We examined associations with pRNFLT measured by spectral-domain OCT in each study using multivariable linear regression and pooled results using random effects meta-analysis. MAIN OUTCOME MEASURES: Determinants of pRNFLT. RESULTS: Mean pRNFLT ranged from 86.8+/-21.4 mum in the Rotterdam Study I to 104.7+/-12.5 mum in the Rotterdam Study III. We found the following factors to be associated with reduced pRNFLT: Older age (beta = -0.38 mum/year; 95% confidence interval [CI], -0.57 to -0.18), higher intraocular pressure (IOP) (beta = -0.36 mum/mmHg; 95% CI, -0.56 to -0.15), visual impairment (beta = -5.50 mum; 95% CI, -9.37 to -1.64), and history of systemic hypertension (beta = -0.54 mum; 95% CI, -1.01 to -0.07) and stroke (beta = -1.94 mum; 95% CI, -3.17 to -0.72). A suggestive, albeit nonsignificant, association was observed for dementia (beta = -3.11 mum; 95% CI, -6.22 to 0.01). Higher pRNFLT was associated with more hyperopic spherical equivalent (beta = 1.39 mum/diopter; 95% CI, 1.19-1.59) and smoking (beta = 1.53 mum; 95% CI, 1.00-2.06 for current smokers compared with never-smokers). CONCLUSIONS: In addition to previously described determinants such as age and refraction, we found that systemic vascular and neurovascular diseases were associated with reduced pRNFLT. These may be of clinical relevance, especially in glaucoma monitoring of patients with newly occurring vascular comorbidities

Prevalence of Age-Related Macular Degeneration in Europe: The Past and the Future

Purpose Age-related macular degeneration (AMD) is a frequent, complex disorder in elderly of European ancestry. Risk profiles and treatment options have changed considerably over the years, which may have affected disease prevalence and outcome. We determined the prevalence of early and late AMD in Europe from 1990 to 2013 using the European Eye Epidemiology (E3) consortium, and made projections for the future. Design Meta-analysis of prevalence data. Participants A total of 42 080 individuals 40 years of age and older participating in 14 population-based cohorts from 10 countries in Europe. Methods AMD was diagnosed based on fundus photographs using the Rotterdam Classification. Prevalence of early and late AMD was calculated using random-effects meta-analysis stratified for age, birth cohort, gender, geographic region, and time period of the study. Best-corrected visual acuity (BCVA) was compared between late AMD subtypes; geographic atrophy (GA) and choroidal neovascularization (CNV). Main Outcome Measures Prevalence of early and late AMD, BCVA, and number of AMD cases. Results Prevalence of early AMD increased from 3.5% (95% confidence interval [CI] 2.1%–5.0%) in those aged 55–59 years to 17.6% (95%

Dépose des ancrages radiculaires : méthodologie

Lors d’un délabrement coronaire important, la réalisation d’une coiffe prothétique permettra de rétablir l’esthétique et la fonction perdues de la dent dépulpée. Un ancrage radiculaire assurera la rétention de cette reconstitution coronaire.<br>De nos jours, le retraitement endodontique est un acte de plus en plus courant dans le quotidien d’un praticien. En cas de maladie périapicale récidivante, les deux alternatives thérapeutiques sont le traitement orthograde non chirurgical et le traitement chirurgical, bien que le retraitement conservateur soit le plus sollicité. Quelle que soit l’option choisie, cette décision sera prise de manière réfléchie, après avoir informé le patient.<br>L’objectif sera de décrire les différentes méthodes de dépose des ancrages radiculaires, des techniques anciennes jusqu’aux plus récentes. Les protocoles se baseront essentiellement sur la vibration ultrasonore et la traction forcée. En outre, nous expliquerons les avantages, les inconvénients et les complications pouvant survenir à la suite de ce geste clinique

Rare variants in CFI, C3 and C9 are associated with high risk of advanced age-related macular degeneration

To define the role of rare variants in advanced age-related macular degeneration (AMD) risk, we sequenced the exons of 681 genes within AMD-associated loci and pathways in 2,493 cases and controls. We first tested each gene for increased or decreased burden of rare variants in cases compared to controls. We found that 7.8% of AMD cases compared to 2.3% of controls are carriers of rare missense CFI variants (OR=3.6, p=2×10(−8)). There was a predominance of dysfunctional variants in cases compared to controls. We then tested individual variants for association to disease. We observed significant association with rare missense alleles outside CFI. Genotyping in 5,115 independent samples confirmed associations to AMD with a K155Q allele in C3 (replication p=3.5×10(−5), OR=2.8; joint p=5.2×10(−9), OR=3.8) and a P167S allele in C9 (replication p=2.4×10(−5), OR=2.2; joint p=6.5×10(−7), OR=2.2). Finally, we show that the 155Q allele in C3 results in resistance to proteolytic inactivation by CFH and CFI. These results implicate loss of C3 protein regulation and excessive alternative complement activation in AMD pathogenesis, thus informing both the direction of effect and mechanistic underpinnings of this disorder

Mucormycosis in intensive care unit: surgery is a major prognostic factor in patients with hematological malignancy

International audienceBackgroundMucormycosis is an invasive fungal infection, with an increasing incidence especially in patients with hematological malignancies. Its prognosis is poor because of its high invasive power and its intrinsic low susceptibility to antifungal agents. We aimed to describe the epidemiology of mucormycosis in intensive care units (ICU) and evaluate the outcomes. We performed a retrospective multi-center study in 16 French ICUs between 2008 and 2017. We compared the patients who survived in ICU and the patients who did not to identify factors associated with ICU survival. Then, we focused on the subgroup of patients with hematological malignancies.ResultsMucormycosis was diagnosed in 74 patients during the study period. Among them, 60 patients (81%) were immunocompromised: 41 had hematological malignancies, 9 were solid organ transplant recipients, 31 received long-term steroids, 11 had diabetes, 24 had malnutrition. Only 21 patients survived to ICU stay (28.4%) with a median survival of 22 days (Q1–Q3 = 9–106) and a survival rate at day 28 and day 90, respectively, of 35.1% and 26.4%. Survivors were significantly younger (p = 0.001), with less frequently hematological malignancies (p = 0.02), and less malnutrition (p = 0.05). Median survival in patients with hematological malignancies (n = 41) was 15 days (Q1–Q3 = 5–23.5 days). In this subgroup, curative surgery was a major factor associated with survival in multivariate analysis (odds ratio = 0.71, [0.45–0.97], p < 0.001).ConclusionOverall prognosis of mucormycosis in ICU remains poor, especially in patients with hematological malignancies. In this subgroup of patients, a therapeutic strategy including curative surgery was the main factor associated with survival

Feeder-free culture of human pluripotent stem cells drives MDM4-mediated gain of chromosome 1q.

Culture-acquired variants in human pluripotent stem cells (hPSCs) hinder their applications in research and clinic. However, the mechanisms that underpin selection of variants remain unclear. Here, through analysis of comprehensive karyotyping datasets from over 23,000 hPSC cultures of more than 1,500 lines, we explored how culture conditions shape variant selection. Strikingly, we identified an association of chromosome 1q gains with feeder-free cultures and noted a rise in its prevalence in recent years, coinciding with increased usage of feeder-free regimens. Competition experiments of multiple isogenic lines with and without a chromosome 1q gain confirmed that 1q variants have an advantage in feeder-free (E8/vitronectin), but not feeder-based, culture. Mechanistically, we show that overexpression of MDM4, located on chromosome 1q, drives variants' advantage in E8/vitronectin by alleviating genome damage-induced apoptosis, which is lower in feeder-based conditions. Our study explains condition-dependent patterns of hPSC aberrations and offers insights into the mechanisms of variant selection

Increased High-Density Lipoprotein Levels Associated with Age-Related Macular Degeneration Evidence from the EYE-RISK and European Eye Epidemiology Consortia

Purpose: Genetic and epidemiologic studies have shown that lipid genes and high-density lipoproteins (HDLs) are implicated in age-related macular degeneration (AMD). We studied circulating lipid levels in relationship to AMD in a large European dataset. Design: Pooled analysis of cross-sectional data. Participants: Individuals (N = 30 953) aged 50 years or older participating in the European Eye Epidemiology (E3) consortium and 1530 individuals from the Rotterdam Study with lipid subfraction data. Methods: AMD features were graded on fundus photographs using the Rotterdam classification. Routine blood lipid measurements, genetics, medication, and potential confounders were extracted from the E3 database. In a subgroup of the Rotterdam Study, lipid subfractions were identified by the Nightingale biomarker platform. Random-intercepts mixed-effects models incorporating confounders and study site as a random effect were used to estimate associations. Main Outcome Measures: AMD features and stage; lipid measurements. Results: HDL was associated with an increased risk of AMD (odds ratio [OR], 1.21 per 1-mmol/l increase; 95% confidence interval [CI], 1.14-1.29), whereas triglycerides were associated with a decreased risk (OR, 0.94 per 1-mmol/l increase; 95% CI, 0.91-0.97). Both were associated with drusen size. Higher HDL raised the odds of larger drusen, whereas higher triglycerides decreases the odds. LDL cholesterol reached statistical significance only in the association with early AMD (P = 0.045). Regarding lipid subfractions, the concentration of extra-large HDL particles showed the most prominent association with AMD (OR, 1.24; 95% CI, 1.10-1.40). The cholesteryl ester transfer protein risk variant (rs17231506) for AMD was in line with increased HDL levels (P = 7.7 x 10(-7)), but lipase C risk variants (rs2043085, rs2070895) were associated in an opposite way (P = 1.0 x 10(-6) and P = 1.6 x 10(-4)). Conclusions: Our study suggested that HDL cholesterol is associated with increased risk of AMD and that triglycerides are negatively associated. Both show the strongest association with early AMD and drusen. Extra-large HDL subfractions seem to be drivers in the relationship with AMD, and variants in lipid genes play a more ambiguous role in this association. Whether systemic lipids directly influence AMD or represent lipid metabolism in the retina remains to be answered. (C) 2018 by the American Academy of Ophthalmolog