Clinical consequences of BRCA2 hypomorphism

Altres ajuts: Asociación Española contra el Cáncer (LABAE16020PORTT)Altres ajuts: Asociación Española contra el Cáncer (ERAPERMED2019-215)The tumor suppressor FANCD1/BRCA2 is crucial for DNA homologous recombination repair (HRR). BRCA2 biallelic pathogenic variants result in a severe form of Fanconi anemia (FA) syndrome, whereas monoallelic pathogenic variants cause mainly hereditary breast and ovarian cancer predisposition. For decades, the co-occurrence in trans with a clearly pathogenic variant led to assume that the other allele was benign. However, here we show a patient with biallelic BRCA2 (c.1813dup and c.7796 A > G) diagnosed at age 33 with FA after a hypertoxic reaction to chemotherapy during breast cancer treatment. After DNA damage, patient cells displayed intermediate chromosome fragility, reduced survival, cell cycle defects, and significantly decreased RAD51 foci formation. With a newly developed cell-based flow cytometric assay, we measured single BRCA2 allele contributions to HRR, and found that expression of the missense allele in a BRCA2 KO cellular background partially recovered HRR activity. Our data suggest that a hypomorphic BRCA2 allele retaining 37-54% of normal HRR function can prevent FA clinical phenotype, but not the early onset of breast cancer and severe hypersensitivity to chemotherapy

Association of circulating microRNAs with coronary artery disease and usefulness for reclassification of healthy individuals: the REGICOR Study

Risk prediction tools cannot identify most individuals at high coronary artery disease (CAD) risk. Oxidized low-density lipoproteins (oxLDLs) and microRNAs are actively involved in atherosclerosis. Our aim was to examine the association of CAD and oxLDLs-induced microRNAs, and to assess the microRNAs predictive capacity of future CAD events. Human endothelial and vascular smooth muscle cells were treated with oxidized/native low-density lipoproteins, and microRNA expression was analyzed. Differentially expressed and CAD-related miRNAs were examined in serum samples from (1) a case-control study with 476 myocardial infarction (MI) patients and 487 controls, and (2) a case-cohort study with 105 incident CAD cases and 455 randomly-selected cohort participants. MicroRNA expression was analyzed with custom OpenArray plates, log rank tests and Cox regression models. Twenty-one microRNAs, two previously undescribed (hsa-miR-193b-5p and hsa-miR-1229-5p), were up- or down-regulated upon cell treatment with oxLDLs. One of the 21, hsa-miR-122-5p, was also upregulated in MI cases (fold change = 4.85). Of the 28 CAD-related microRNAs tested, 11 were upregulated in MI cases -1 previously undescribed (hsa-miR-16-5p)-, and 1/11 was also associated with CAD incidence (adjusted hazard ratio = 0.55 (0.35-0.88)) and improved CAD risk reclassification, hsa-miR-143-3p. We identified 2 novel microRNAs modulated by oxLDLs in endothelial cells, 1 novel microRNA upregulated in AMI cases compared to controls, and one circulating microRNA that improved CAD risk classification.This work was supported by the Spain’s Ministry of Science and Innovation (Madrid, Spain), co-financed with European Union European Regional Development Funds –ERDF- (FIS-CP12/03287, FIS-14/00449, FIS-PI081327, INTRASALUD PI11/01801, PI15/00064, IJCI-2016-29393 to DdG-C, CIBERCV (CB16/11/00229, 00246, 00403), CIBERESP CB06/02/0029, CIBEROBN CB06/03/0028); the Spain’s ministry of Economy and Competiveness (Madrid, Spain) (BFU2016-75360-R); the BBVA Foundation (Bilbao, Spain) (PR-16-BIO-CAR-0041); the Health Departament of the Generalitat de Catalunya (Barcelona, Spain) through the Agència de Gestió d’Ajuts Universitaris de Recerca de Catalunya (AGAUR) (Barcelona, Spain) (2017SGR222), the Strategic Plan for research and health innovation (PERIS) (Barcelona, Spain) (SLT006/17/00234, SLT002/16/00145, SLT006/17/00029 to IRD); and by the Junta de Castilla y León (Valladolid, Spain) (VA114P17). CIBERs of Pathophysiology of Obesity and Nutrition (CIBEROBN), Cardiovascular Diseases (CIBERCV), and Epidemiology (CIBERESP) are initiatives of the Instituto de Salud Carlos III, Madrid, Spain