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We report a medium‐throughput drug‐screening platform (METPlatform) based on organotypic cultures that allows to evaluate inhibitors against metastases growing in situ . By applying this approach to the unmet clinical need of brain metastasis, we identified several vulnerabilities. Among them, a blood–brain barrier permeable HSP90 inhibitor showed high potency against mouse and human brain metastases at clinically relevant stages of the disease, including a novel model of local relapse after neurosurgery. Furthermore, in situ proteomic analysis applied to metastases treated with the chaperone inhibitor uncovered a novel molecular program in brain metastasis, which includes biomarkers of poor prognosis and actionable mechanisms of resistance. Our work validates METPlatform as a potent resource for metastasis research integrating drug‐screening and unbiased omic approaches that is compatible with human samples. Thus, this clinically relevant strategy is aimed to personalize the management of metastatic disease in the brain and elsewhere. Synopsis A novel drug‐screening platform compatible with patient‐derived samples identifies effective therapies to prevent brain metastasis. METPlatform is a novel drug‐screening strategy to identify vulnerabilities of metastasis while colonizing organs ex vivo . METPlatform identified hits that were confirmed in vivo as effective against brain metastasis. METPlatform allows to dissect the molecular mechanisms downstream of target inhibition using omic approaches. METPlatform has a potential value as a patient \"avatar\". Graphical Abstract A novel drug‐screening platform compatible with patient‐derived samples identifies effective therapies to prevent brain metastasis.

Werner syndrome (WS) is an inherited disorder characterized by premature onset of aging, genomic instability, and increased cancer incidence. The disease is caused by loss of function mutations of the WRN gene, a RecQ family member with both helicase and exonuclease activities. However, despite its putative tumorsuppressor function, little is known about the contribution of WRN to human sporadic malignancies. Here, we report that WRN function is abrogated in human cancer cells by transcriptional silencing associated with CpG island-promoter hypermethylation. We also show that, at the biochemical and cellular levels, the epigenetic inactivation of WRN leads to the loss of WRN-associated exonuclease activity and increased chromosomal instability and apoptosis induced by topoisomerase inhibitors. The described phenotype is reversed by the use of a DNA-demethylating agent or by the reintroduction of WRN into cancer cells displaying methylationdependent silencing of WRN. Furthermore, the restoration of WRN expression induces tumor-suppressor-like features, such as reduced colony formation density and inhibition of tumor growth in nude mouse xenograft models. Screening a large collection of human primary tumors (n = 630) from different cell types revealed that WRN CpG island hypermethylation was a common event in epithelial and mesenchymal tumorigenesis. Most importantly, WRN hypermethylation in colorectal tumors was a predictor of good clinical response to the camptothecin analogue irinotecan, a topoisomerase inhibitor commonly used in the clinical setting for the treatment of this tumor type. These findings highlight the importance of WRN epigenetic inactivation in human cancer, leading to enhanced chromosomal instability and hypersensitivity to chemotherapeutic drugs.

The purpose of this study is to analyze the effect of two genetic polymorphisms, ACTN3 R577X, and ACE I/D, on physical condition in a sample of active older women after a two-year training period. The sample was composed of 300 healthy women over the age of 60 who underwent a two-year training program. Adapted tests from the Senior Fitness Test were used. The genotyping of the polymorphisms was obtained from the participants’ DNA via buccal swabs. The analysis of the ACE polymorphism did not reveal differences between genotypes. The analysis of the R577X polymorphism showed a favorable effect for the ACTN3 XX genotype in tests for leg strength (p: 0.001) after training, compared to the other genotypes, and also in the analysis of the combined effect of the polymorphism (ACE II + ACTN3 RX/XX). The intragroup effect revealed an improvement in arm strength for carriers of the X allele after 24 months of training (p < 0.05). The endurance values significantly worsened in all study groups. Conclusions: The R577X polymorphism of ACTN3 may have an important role in capacities related to muscle strength, providing a beneficial effect for carriers of the X allele.

The purpose of the present work is to underline the importance of obtaining a standardized procedure to ensure and evaluate both clinical and research usability of human tissue samples. The study, which was carried out by the Biospecimen Science Working Group of the Spanish Biobank Network, is based on a general overview of the current situation about quality assurance in human tissue biospecimens. It was conducted an exhaustive review of the analytical techniques used to evaluate the quality of human tissue samples over the past 30 years, as well as their reference values if they were published, and classified them according to the biomolecules evaluated: (i) DNA, (ii) RNA, and (iii) soluble or/and fixed proteins for immunochemistry. More than 130 publications released between 1989 and 2019 were analysed, most of them reporting results focused on the analysis of tumour and biopsy samples. A quality assessment proposal with an algorithm has been developed for both frozen tissue samples and formalin-fixed paraffin-embedded (FFPE) samples, according to the expected quality of sample based on the available pre-analytical information and the experience of the participants in the Working Group. The high heterogeneity of human tissue samples and the wide number of pre-analytic factors associated to quality of samples makes it very difficult to harmonize the quality criteria. However, the proposed method to assess human tissue sample integrity and antigenicity will not only help to evaluate whether stored human tissue samples fit for the purpose of biomarker development, but will also allow to perform further studies, such as assessing the impact of different pre-analytical factors on very well characterized samples or evaluating the readjustment of tissue sample collection, processing and storing procedures. By ensuring the quality of the samples used on research, the reproducibility of scientific results will be guaranteed.

The genetic basis of severe COVID-19 has been thoroughly studied, and many genetic risk factors shared between populations have been identified. However, reduced sample sizes from non-European groups have limited the discovery of population-specific common risk loci. In this second study nested in the SCOURGE consortium, we conducted a genome-wide association study (GWAS) for COVID-19 hospitalization in admixed Americans, comprising a total of 4702 hospitalized cases recruited by SCOURGE and seven other participating studies in the COVID-19 Host Genetic Initiative. We identified four genome-wide significant associations, two of which constitute novel loci and were first discovered in Latin American populations ( BAZ2B and DDIAS ). A trans-ethnic meta-analysis revealed another novel cross-population risk locus in CREBBP . Finally, we assessed the performance of a cross-ancestry polygenic risk score in the SCOURGE admixed American cohort. This study constitutes the largest GWAS for COVID-19 hospitalization in admixed Latin Americans conducted to date. This allowed to reveal novel risk loci and emphasize the need of considering the diversity of populations in genomic research.

BCL-6 somatic mutations have been described in normal and tumoral B lymphocytes, associated with germinal center transit. We analyzed mutations in the major mutation cluster of BCL-6 in a series of 45 large B-cell lymphomas (LBCLs) and 15 Burkitt's lymphomas, and their relation to the level of BCL-6 expression and clinical outcome. Mutations in LBCL cases revealed the existence of two distinct, short mutational hot spots, spanning positions 106 to 127 and 423 to 443, in which the mutation frequency was higher than expected ( P < 0.001). Mutations in the 423 to 443 subcluster were associated with an increased level of expression, although this was not the case with the 106 to 127 cluster. Additionally, LBCL cases characterized by the presence of mutations in the 423 to 443 cluster showed an increased overall survival ( P < 0.05) when compared with the nonmutated LBCL cases in these positions. Burkitt's lymphoma cases showed a slightly lower frequency of mutations with a nonclustered distribution and lacked any relationship with the level of expression or any clinical characteristic. Findings from LBCLs suggest that the 423 to 443 cluster includes a regulatory region that is of importance for BCL-6 expression. Deregulation of BCL-6 expression caused by these mutations could play an important role in lymphoma genesis or progression.

Oct1 and Oct2 are transcription factors of the POU homeo-domain family that bind to the Ig gene octamer sites, regulating B-cell-specific genes. The function of these transcription factors is dependent on the activity of B-cell-restricted coactivators such as BOB.1/OBF.1. Independent studies of the expression of these proteins in non-Hodgkin's lymphoma have been restricted to single markers, and most lack data concerning immunohistochemical expression. Thus, we have investigated the expression of Oct1, Oct2, and BOB.1/OBF.1 in human reactive lymphoid tissue and in a series of 140 Hodgkin and non-Hodgkin's lymphomas. None of these proteins was found to be restricted to B cells, although only B cells expressed high levels of all three markers. Additionally, germinal center B cells showed stronger Oct2 and BOB.1/OBF.1 staining. Consequently, most B-cell lymphomas showed reactivity for all three antibodies. Oct2 expression was significantly higher in germinal center-derived lymphomas, although other B-cell lymphomas also displayed a high level of Oct2 expression. Although T-cell lymphomas and Hodgkin's lymphomas expressed some of these proteins, they commonly exhibited less reactivity than B-cell lymphomas. Despite not being entirely cell-specific, the strong nuclear expression of Oct2 and BOB.1/OBF.1 by germinal center- derived lymphomas makes these antibodies a potentially useful tool in lymphoma diagnosis.

Background: Extracellular vesicles (EVs) are of great interest given their involvement in multiple biological functions and in therapeutic use: biomarkers for diagnosis or monitoring of certain diseases, vectors for the transport and administration of certain drugs or as therapeutic agents per se. Most researchers working with EVs need controls/references for their studies. Nowadays, there is not any consensus regarding the type and number of controls to be studied. Methods: In order to know better the needs of EVs researchers in the field of controls, an online survey about the convenience for researchers of having controls for their studies was distributed, the responses being highly favourable. Results: A total of 40 answers were received from researchers focused on pathologies such as cancer, cardiovascular and infectious diseases. Most of these studies were focused on fields such as the identification of biomarkers, diagnosis or prognosis of diseases. An average of about 60 cases/study (range: 10-300) are included, the main source of obtaining VEs being plasma, cell culture media and urine. The method preferred for obtaining exosomes was ultracentrifugation, although there were already a variety of procedures for its isolation (ultrafiltration, commercial isolation kits). The number of controls used in each study, was also very variable: same number than cases, or 20% of the analysed cases, with a range between 10 and 100 controls per study. All EVs researchers would be interested in having a collection of controls because they considered it very useful and they all would be potential users, especially if this collection was aimed at adults and both sexes. Regarding the type of characterization in which the researchers would be interested, most of them opted for proteomics and transcriptomics and they considered the association of information regarding sample donors very useful. Summary/Conclusion: In light of these needs, we decided to propose the EXOSPORE, a coordinated action between Biobanks and other institutions to constitute a representative collection of EVs isolated from plasma and urine that can be used as controls in the field of biomedical research.

Absence of a reliable method for determining the level of c-myc expression has impeded the analysis of its biological and clinical relevance in tumors. We have standardized the conditions for a real-time reverse transcription polymerase chain reaction analysis for c-myc expression, including the selection of an endogenous reference (18S rRNA), the adequate number of measurements for each sample (2 cDNA in triplicate), and suitable controls for determining inter- and intrarun variability (standard curve and calibrator). Subsequently, in a series of 56 non-Hodgkin's lymphomas, we analyzed the expression of c-myc mRNA, using real-time reverse transcription polymerase chain reaction, and of other functionally related proteins (bcl-6, p27, cyclin D3, and p53). As expected, all eight Burkitt's lymphoma cases analyzed had high levels of c-myc mRNA expression compared with that observed in reactive lymphoid tissue. There was a wider range of expression in diffuse large B-cell lymphoma, with 30% (15 of 48) of cases overexpressing c-myc. This overexpression was largely independent of c-myc translocations (4 of 5), as demonstrated by fluorescence in situ hybridization. In this large B-cell lymphoma series, a high level of c-myc expression predicted lower survival probability, irrespectively of the International Prognostic Index risk group classification. A slightly increased frequency of p53 inactivation was observed in the cases with c-myc overexpression, which suggests a growth advantage in lymphomas with concurrent deregulation of c-myc and p53. In addition, a moderate increase in bcl-6 protein expression was observed in the c-myc–positive cases, suggesting the existence of a complex interrelationship between these two genes. These findings suggest that c-myc may play a relevant role in the pathogenesis of a subset of large B-cell lymphoma and suggest the existence of additional regulatory mechanisms of c-myc expression to c-myc rearrangements.