Core Circadian Clock Genes Regulate Leukemia Stem Cells in AML.

Leukemia stem cells (LSCs) have the capacity to self-renew and propagate disease upon serial transplantation in animal models, and elimination of this cell population is required for curative therapies. Here, we describe a series of pooled, in vivo RNAi screens to identify essential transcription factors (TFs) in a murine model of acute myeloid leukemia (AML) with genetically and phenotypically defined LSCs. These screens reveal the heterodimeric, circadian rhythm TFs Clock and Bmal1 as genes required for the growth of AML cells in vitro and in vivo. Disruption of canonical circadian pathway components produces anti-leukemic effects, including impaired proliferation, enhanced myeloid differentiation, and depletion of LSCs. We find that both normal and malignant hematopoietic cells harbor an intact clock with robust circadian oscillations, and genetic knockout models reveal a leukemia-specific dependence on the pathway. Our findings establish a role for the core circadian clock genes in AML.

PanDrugs2: prioritizing cancer therapies using integrated individual multi-omics data.

Genomics studies routinely confront researchers with long lists of tumor alterations detected in patients. Such lists are difficult to interpret since only a minority of the alterations are relevant biomarkers for diagnosis and for designing therapeutic strategies. PanDrugs is a methodology that facilitates the interpretation of tumor molecular alterations and guides the selection of personalized treatments. To do so, PanDrugs scores gene actionability and drug feasibility to provide a prioritized evidence-based list of drugs. Here, we introduce PanDrugs2, a major upgrade of PanDrugs that, in addition to somatic variant analysis, supports a new integrated multi-omics analysis which simultaneously combines somatic and germline variants, copy number variation and gene expression data. Moreover, PanDrugs2 now considers cancer genetic dependencies to extend tumor vulnerabilities providing therapeutic options for untargetable genes. Importantly, a novel intuitive report to support clinical decision-making is generated. PanDrugs database has been updated, integrating 23 primary sources that support >74K drug-gene associations obtained from 4642 genes and 14 659 unique compounds. The database has also been reimplemented to allow semi-automatic updates to facilitate maintenance and release of future versions. PanDrugs2 does not require login and is freely available at https://www.pandrugs.org/.

IL-1 mediates microbiome-induced inflammaging of hematopoietic stem cells in mice.

Aging is associated with impaired hematopoietic and immune function caused in part by decreased fitness in the hematopoietic stem cell (HSC) population and an increased myeloid differentiation bias. The reasons for this aging-associated HSC impairment are incompletely understood. Here we demonstrate that older specific pathogen free (SPF) wild-type (WT) mice in contrast to young SPF mice produce more interleukin-1a and interleukin-1b (IL-1a/b) in steady-state bone marrow (BM), with most of the IL-1a/b being derived from myeloid BM cells. Furthermore, blood from steady-state older SPF WT mice contains higher levels of microbe-associated molecular patterns, specifically TLR4 and TLR8 ligands. In addition, BM myeloid cells from older mice produce more IL-1b in vitro, and older mice show higher and more durable IL-1a/b responses upon stimulation with lipopolysaccharide in vivo. To test whether HSC aging is driven by IL-1a/b, we evaluated HSCs from IL-1 receptor 1 (IL-1R1) knockout (KO) mice. Indeed, older HSCs from IL-1R1KO mice show significantly mitigated aging-associated inflammatory signatures. Moreover, HSCs from older IL-1R1KO and from germ-free mice maintain unbiased lymphomyeloid hematopoietic differentiation upon transplantation, thus resembling this functionality of young HSCs. Importantly, in vivo antibiotic suppression of microbiota or pharmacologic blockade of IL-1 signaling in older WT mice was similarly sufficient to reverse myeloid-biased output of their HSC populations. Collectively, our data define the microbiome/IL-1/IL-1R1 axis as a key, self-sustaining and also therapeutically partially reversible driver of HSC inflammaging.

Whole-genome CRISPR screening identifies N-glycosylation as a genetic and therapeutic vulnerability in CALR-mutant MPNs.

Calreticulin (CALR) mutations are frequent, disease-initiating events in myeloproliferative neoplasms (MPNs). Although the biological mechanism by which CALR mutations cause MPNs has been elucidated, there currently are no clonally selective therapies for CALR-mutant MPNs. To identify unique genetic dependencies in CALR-mutant MPNs, we performed a whole-genome clustered regularly interspaced short palindromic repeats (CRISPR) knockout depletion screen in mutant CALR-transformed hematopoietic cells. We found that genes in the N-glycosylation pathway (among others) were differentially depleted in mutant CALR-transformed cells as compared with control cells. Using a focused pharmacological in vitro screen targeting unique vulnerabilities uncovered in the CRISPR screen, we found that chemical inhibition of N-glycosylation impaired the growth of mutant CALR-transformed cells, through a reduction in MPL cell surface expression. We treated Calr-mutant knockin mice with the N-glycosylation inhibitor 2-deoxy-glucose (2-DG) and found a preferential sensitivity of Calr-mutant cells to 2-DG as compared with wild-type cells and normalization of key MPNs disease features. To validate our findings in primary human cells, we performed megakaryocyte colony-forming unit (CFU-MK) assays. We found that N-glycosylation inhibition significantly reduced CFU-MK formation in patient-derived CALR-mutant bone marrow as compared with bone marrow derived from healthy donors. In aggregate, our findings advance the development of clonally selective treatments for CALR-mutant MPNs.

3D chromatin connectivity underlies replication origin efficiency in mouse embryonic stem cells.

In mammalian cells, chromosomal replication starts at thousands of origins at which replisomes are assembled. Replicative stress triggers additional initiation events from 'dormant' origins whose genomic distribution and regulation are not well understood. In this study, we have analyzed origin activity in mouse embryonic stem cells in the absence or presence of mild replicative stress induced by aphidicolin, a DNA polymerase inhibitor, or by deregulation of origin licensing factor CDC6. In both cases, we observe that the majority of stress-responsive origins are also active in a small fraction of the cell population in a normal S phase, and stress increases their frequency of activation. In a search for the molecular determinants of origin efficiency, we compared the genetic and epigenetic features of origins displaying different levels of activation, and integrated their genomic positions in three-dimensional chromatin interaction networks derived from high-depth Hi-C and promoter-capture Hi-C data. We report that origin efficiency is directly proportional to the proximity to transcriptional start sites and to the number of contacts established between origin-containing chromatin fragments, supporting the organization of origins in higher-level DNA replication factories.

bollito: a flexible pipeline for comprehensive single-cell RNA-seq analyses.

SUMMARY: bollito is an automated, flexible and parallelizable computational pipeline for the comprehensive analysis of single-cell RNA-seq data. Starting from FASTQ files or preprocessed expression matrices, bollito performs both basic and advanced tasks in single-cell analysis integrating >30 state-of-the-art tools. This includes quality control, read alignment, dimensionality reduction, clustering, cell-marker detection, differential expression, functional analysis, trajectory inference and RNA velocity. bollito is built using the Snakemake workflow management system, which easily connects each execution step and facilitates the reproducibility of results. bollito's modular design makes it easy to incorporate other packages into the pipeline enabling its expansion with new functionalities. AVAILABILITY AND IMPLEMENTATION: Source code is freely available at https://gitlab.com/bu_cnio/bollito under the MIT license. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

DREIMT: a drug repositioning database and prioritization tool for immunomodulation.

MOTIVATION: Drug immunomodulation modifies the response of the immune system and can be therapeutically exploited in pathologies such as cancer and autoimmune diseases. RESULTS: DREIMT is a new hypothesis-generation web tool, which performs drug prioritization analysis for immunomodulation. DREIMT provides significant immunomodulatory drugs targeting up to 70 immune cells subtypes through a curated database that integrates 4960 drug profiles and ∼2600 immune gene expression signatures. The tool also suggests potential immunomodulatory drugs targeting user-supplied gene expression signatures. Final output includes drug-signature association scores, FDRs and downloadable plots and results tables. AVAILABILITYAND IMPLEMENTATION: http://www.dreimt.org. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

A comprehensive database for integrated analysis of omics data in autoimmune diseases.

BACKGROUND: Autoimmune diseases are heterogeneous pathologies with difficult diagnosis and few therapeutic options. In the last decade, several omics studies have provided significant insights into the molecular mechanisms of these diseases. Nevertheless, data from different cohorts and pathologies are stored independently in public repositories and a unified resource is imperative to assist researchers in this field. RESULTS: Here, we present Autoimmune Diseases Explorer ( https://adex.genyo.es ), a database that integrates 82 curated transcriptomics and methylation studies covering 5609 samples for some of the most common autoimmune diseases. The database provides, in an easy-to-use environment, advanced data analysis and statistical methods for exploring omics datasets, including meta-analysis, differential expression or pathway analysis. CONCLUSIONS: This is the first omics database focused on autoimmune diseases. This resource incorporates homogeneously processed data to facilitate integrative analyses among studies.

Precision medicine needs pioneering clinical bioinformaticians.

Success in precision medicine depends on accessing high-quality genetic and molecular data from large, well-annotated patient cohorts that couple biological samples to comprehensive clinical data, which in conjunction can lead to effective therapies. From such a scenario emerges the need for a new professional profile, an expert bioinformatician with training in clinical areas who can make sense of multi-omics data to improve therapeutic interventions in patients, and the design of optimized basket trials. In this review, we first describe the main policies and international initiatives that focus on precision medicine. Secondly, we review the currently ongoing clinical trials in precision medicine, introducing the concept of 'precision bioinformatics', and we describe current pioneering bioinformatics efforts aimed at implementing tools and computational infrastructures for precision medicine in health institutions around the world. Thirdly, we discuss the challenges related to the clinical training of bioinformaticians, and the urgent need for computational specialists capable of assimilating medical terminologies and protocols to address real clinical questions. We also propose some skills required to carry out common tasks in clinical bioinformatics and some tips for emergent groups. Finally, we explore the future perspectives and the challenges faced by precision medicine bioinformatics.

Saa3 is a key mediator of the protumorigenic properties of cancer-associated fibroblasts in pancreatic tumors.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by the presence of abundant desmoplastic stroma primarily composed of cancer-associated fibroblasts (CAFs). It is generally accepted that CAFs stimulate tumor progression and might be implicated in drug resistance and immunosuppression. Here, we have compared the transcriptional profile of PDGFRα+ CAFs isolated from genetically engineered mouse PDAC tumors with that of normal pancreatic fibroblasts to identify genes potentially implicated in their protumorigenic properties. We report that the most differentially expressed gene, Saa3, a member of the serum amyloid A (SAA) apolipoprotein family, is a key mediator of the protumorigenic activity of PDGFRα+ CAFs. Whereas Saa3-competent CAFs stimulate the growth of tumor cells in an orthotopic model, Saa3-null CAFs inhibit tumor growth. Saa3 also plays a role in the cross talk between CAFs and tumor cells. Ablation of Saa3 in pancreatic tumor cells makes them insensitive to the inhibitory effect of Saa3-null CAFs. As a consequence, germline ablation of Saa3 does not prevent PDAC development in mice. The protumorigenic activity of Saa3 in CAFs is mediated by Mpp6, a member of the palmitoylated membrane protein subfamily of the peripheral membrane-associated guanylate kinases (MAGUK). Finally, we interrogated whether these observations could be translated to a human scenario. Indeed, SAA1, the ortholog of murine Saa3, is overexpressed in human CAFs. Moreover, high levels of SAA1 in the stromal component correlate with worse survival. These findings support the concept that selective inhibition of SAA1 in CAFs may provide potential therapeutic benefit to PDAC patients.

Inactivation of EMILIN-1 by Proteolysis and Secretion in Small Extracellular Vesicles Favors Melanoma Progression and Metastasis.

Several studies have demonstrated that melanoma-derived extracellular vesicles (EVs) are involved in lymph node metastasis; however, the molecular mechanisms involved are not completely defined. Here, we found that EMILIN-1 is proteolyzed and secreted in small EVs (sEVs) as a novel mechanism to reduce its intracellular levels favoring metastasis in mouse melanoma lymph node metastatic cells. Interestingly, we observed that EMILIN-1 has intrinsic tumor and metastasis suppressive-like properties reducing effective migration, cell viability, primary tumor growth, and metastasis. Overall, our analysis suggests that the inactivation of EMILIN-1 by proteolysis and secretion in sEVs reduce its intrinsic tumor suppressive activities in melanoma favoring tumor progression and metastasis.

Hsa-miR-139-5p is a prognostic thyroid cancer marker involved in HNRNPF-mediated alternative splicing.

It is critical to identify biomarkers and functional networks associated with aggressive thyroid cancer to anticipate disease progression and facilitate personalized patient management. We performed miRNome sequencing of 46 thyroid tumors enriched with advanced disease patients with a median follow-up of 96 months. MiRNome profiles correlated with tumor-specific histopathological and molecular features, such as stromal cell infiltration and tumor driver mutation. Differential expression analysis revealed a consistent hsa-miR-139-5p downexpression in primary carcinomas from patients with recurrent/metastatic disease compared to disease-free patients, sustained in paired local metastases and validated in publicly available thyroid cancer series. Exogenous expression of hsa-miR-139-5p significantly reduced migration and proliferation of anaplastic thyroid cancer cells. Proteomic analysis indicated RICTOR, SMAD2/3 and HNRNPF as putative hsa-miR-139-5p targets in our cell system. Abundance of HNRNPF mRNA, encoding an alternative splicing factor involved in cryptic exon inclusion/exclusion, inversely correlated with hsa-miR-139-5p expression in human tumors. RNA sequencing analysis revealed 174 splicing events differentially regulated upon HNRNPF repression in our cell system, affecting genes involved in RTK/RAS/MAPK and PI3K/AKT/MTOR signaling cascades among others. These results point at the hsa-miR-139-5p/HNRNPF axis as a novel regulatory mechanism associated with the modulation of major thyroid cancer signaling pathways and tumor virulence.

vulcanSpot: a tool to prioritize therapeutic vulnerabilities in cancer.

MOTIVATION: Genetic alterations lead to tumor progression and cell survival but also uncover cancer-specific vulnerabilities on gene dependencies that can be therapeutically exploited. RESULTS: vulcanSpot is a novel computational approach implemented to expand the therapeutic options in cancer beyond known-driver genes unlocking alternative ways to target undruggable genes. The method integrates genome-wide information provided by massive screening experiments to detect genetic vulnerabilities associated to tumors. Then, vulcanSpot prioritizes drugs to target cancer-specific gene dependencies using a weighted scoring system based on well known drug-gene relationships and drug repositioning strategies. AVAILABILITY AND IMPLEMENTATION: http://www.vulcanspot.org. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

The use of PanDrugs to prioritize anticancer drug treatments in a case of T-ALL based on individual genomic data.

BACKGROUND: Acute T-cell lymphoblastic leukaemia (T-ALL) is an aggressive disorder derived from immature thymocytes. The variability observed in clinical responses on this type of tumours to treatments, the high toxicity of current protocols and the poor prognosis of patients with relapse or refractory make it urgent to find less toxic and more effective therapies in the context of a personalized medicine of precision. METHODS: Whole exome sequencing and RNAseq were performed on DNA and RNA respectively, extracted of a bone marrow sample from a patient diagnosed with tumour primary T-ALL and double negative thymocytes from thymus control samples. We used PanDrugs, a computational resource to propose pharmacological therapies based on our experimental results, including lists of variants and genes. We extend the possible therapeutic options for the patient by taking into account multiple genomic events potentially sensitive to a treatment, the context of the pathway and the pharmacological evidence already known by large-scale experiments. RESULTS: As a proof-of-principle we used next-generation-sequencing technologies (Whole Exome Sequencing and RNA-Sequencing) in a case of diagnosed Pro-T acute lymphoblastic leukaemia. We identified 689 disease-causing mutations involving 308 genes, as well as multiple fusion transcript variants, alternative splicing, and 6652 genes with at least one principal isoform significantly deregulated. Only 12 genes, with 27 pathogenic gene variants, were among the most frequently mutated ones in this type of lymphoproliferative disorder. Among them, 5 variants detected in CTCF, FBXW7, JAK1, NOTCH1 and WT1 genes have not yet been reported in T-ALL pathogenesis. CONCLUSIONS: Personalized genomic medicine is a therapeutic approach involving the use of an individual's information data to tailor drug therapy. Implementing bioinformatics platform PanDrugs enables us to propose a prioritized list of anticancer drugs as the best theoretical therapeutic candidates to treat this patient has been the goal of this article. Of note, most of the proposed drugs are not being yet considered in the clinical practice of this type of cancer opening up the approach of new treatment possibilities.

Whole exome sequencing identifies PLEC, EXO5 and DNAH7 as novel susceptibility genes in testicular cancer.

Testicular germ cell tumors (TGCTs) are a clinically and pathologically heterogeneous disease, and little is known of its genetic basis. Only low susceptibility risk loci have been identified for both sporadic and familial cases. Therefore, we tried to identify new susceptibility genes responsible for familial testicular cancer that may contribute to increasing our knowledge about the genetic basis of the disease. Nineteen Spanish families with at least two affected individuals with TGCT were selected. WES was performed on those individuals using an Illumina Hiseq2000 sequencing platform. Data were analyzed under a monogenic and polygenic model of inheritance, and candidate variants were evaluated in a case-control association study performed on 391 Spanish sporadic cases and 1,170 healthy Spanish controls. Results were replicated in a second series consisting of 101 TGCTs from the Cancer Genome Atlas (TGCA) and 27,000 controls from the Exome Aggregation Consortium (ExAC) database. Logistic regression was carried out to analyze the association strength (risk) of candidate variants obtained among cases and controls in different populations. Despite the sample size, we detected a significant earlier age of onset in familial TGCT (28y) than sporadic cases (33y), using a Mann-Whitney U test. We identified significant variants in the comparative study of TGCT cases (391) versus controls (almost 1,170), and three of them [PLEC (OR = 6.28, p = 6.42 × 10-23 ) (p.Arg2016Trp), EXO5 (OR = 3.37, p = 4.82 × 10-09 ) (p.Arg344AlafsTer10) and DNAH7 (OR = 1.64, p = 0.048)] were replicated as potential candidates that may contribute to explaining the genetic basis of TGCT.

Integrated genomic analysis illustrates the central role of JAK-STAT pathway activation in myeloproliferative neoplasm pathogenesis.

Genomic studies have identified somatic alterations in the majority of myeloproliferative neoplasms (MPN) patients, including JAK2 mutations in the majority of MPN patients and CALR mutations in JAK2-negative MPN patients. However, the role of JAK-STAT pathway activation in different MPNs, and in patients without JAK2 mutations, has not been definitively delineated. We used expression profiling, single nucleotide polymorphism arrays, and mutational profiling to investigate a well-characterized cohort of MPN patients. MPN patients with homozygous JAK2V617F mutations were characterized by a distinctive transcriptional profile. Notably, a transcriptional signature consistent with activated JAK2 signaling is seen in all MPN patients regardless of clinical phenotype or mutational status. In addition, the activated JAK2 signature was present in patients with somatic CALR mutations. Conversely, we identified a gene expression signature of CALR mutations; this signature was significantly enriched in JAK2-mutant MPN patients consistent with a shared mechanism of transformation by JAK2 and CALR mutations. We also identified a transcriptional signature of TET2 mutations in MPN patent samples. Our data indicate that MPN patients, regardless of diagnosis or JAK2 mutational status, are characterized by a distinct gene expression signature with upregulation of JAK-STAT target genes, demonstrating the central importance of the JAK-STAT pathway in MPN pathogenesis.

Bone progenitor dysfunction induces myelodysplasia and secondary leukaemia.

Mesenchymal cells contribute to the 'stroma' of most normal and malignant tissues, with specific mesenchymal cells participating in the regulatory niches of stem cells. By examining how mesenchymal osteolineage cells modulate haematopoiesis, here we show that deletion of Dicer1 specifically in mouse osteoprogenitors, but not in mature osteoblasts, disrupts the integrity of haematopoiesis. Myelodysplasia resulted and acute myelogenous leukaemia emerged that had acquired several genetic abnormalities while having intact Dicer1. Examining gene expression altered in osteoprogenitors as a result of Dicer1 deletion showed reduced expression of Sbds, the gene mutated in Schwachman-Bodian-Diamond syndrome-a human bone marrow failure and leukaemia pre-disposition condition. Deletion of Sbds in mouse osteoprogenitors induced bone marrow dysfunction with myelodysplasia. Therefore, perturbation of specific mesenchymal subsets of stromal cells can disorder differentiation, proliferation and apoptosis of heterologous cells, and disrupt tissue homeostasis. Furthermore, primary stromal dysfunction can result in secondary neoplastic disease, supporting the concept of niche-induced oncogenesis.

MicroRNA deep-sequencing reveals master regulators of follicular and papillary thyroid tumors.

MicroRNA deregulation could be a crucial event in thyroid carcinogenesis. However, current knowledge is based on studies that have used inherently biased methods. Thus, we aimed to define in an unbiased way a list of deregulated microRNAs in well-differentiated thyroid cancer in order to identify diagnostic and prognostic markers. We performed a microRNA deep-sequencing study using the largest well-differentiated thyroid tumor collection reported to date, comprising 127 molecularly characterized tumors with follicular or papillary patterns of growth and available clinical follow-up data, and 17 normal tissue samples. Furthermore, we integrated microRNA and gene expression data for the same tumors to propose targets for the novel molecules identified. Two main microRNA expression profiles were identified: one common for follicular-pattern tumors, and a second for papillary tumors. Follicular tumors showed a notable overexpression of several members of miR-515 family, and downregulation of the novel microRNA miR-1247. Among papillary tumors, top upregulated microRNAs were miR-146b and the miR-221~222 cluster, while miR-1179 was downregulated. BRAF-positive samples displayed extreme downregulation of miR-7 and -204. The identification of the predicted targets for the novel molecules gave insights into the proliferative potential of the transformed follicular cell. Finally, by integrating clinical follow-up information with microRNA expression, we propose a prediction model for disease relapse based on expression of two miRNAs (miR-192 and let-7a) and several other clinicopathological features. This comprehensive study complements the existing knowledge about deregulated microRNAs in the development of well-differentiated thyroid cancer and identifies novel markers associated with recurrence-free survival.

Niche-based screening identifies small-molecule inhibitors of leukemia stem cells.

Efforts to develop more effective therapies for acute leukemia may benefit from high-throughput screening systems that reflect the complex physiology of the disease, including leukemia stem cells (LSCs) and supportive interactions with the bone marrow microenvironment. The therapeutic targeting of LSCs is challenging because LSCs are highly similar to normal hematopoietic stem and progenitor cells (HSPCs) and are protected by stromal cells in vivo. We screened 14,718 compounds in a leukemia-stroma co-culture system for inhibition of cobblestone formation, a cellular behavior associated with stem-cell function. Among those compounds that inhibited malignant cells but spared HSPCs was the cholesterol-lowering drug lovastatin. Lovastatin showed anti-LSC activity in vitro and in an in vivo bone marrow transplantation model. Mechanistic studies demonstrated that the effect was on target, via inhibition of HMG-CoA reductase. These results illustrate the power of merging physiologically relevant models with high-throughput screening.

Distinct roles for long-term hematopoietic stem cells and erythroid precursor cells in a murine model of Jak2V617F-mediated polycythemia vera.

In the current model of the pathogenesis of polycythemia vera (PV), the JAK2V617F mutation arises in hematopoietic stem cells (HSCs) that maintain the disease, while erythroid precursor populations expand, resulting in excessive red blood cell production. We examined the role of these specific cell populations using a conditional Jak2V617F knockin murine model. We demonstrate that the most immature long-term (LT) HSCs are solely responsible for initiating and maintaining the disease in vivo and that Jak2V617F mutant LT-HSCs dominate hematopoiesis over time. When we induced Jak2V617F expression in erythropoietin receptor expressing precursor cells, the mice developed elevated hematocrit, expanded erythroid precursors, and suppressed erythropoietin levels. However, the disease phenotype was significantly attenuated compared with mice expressing Jak2V617F in LT-HSCs. In addition to developing a PV phenotype, all mice transplanted with Jak2V617F LT-HSCs underwent myelofibrotic transformation over time. These findings recapitulate the development of post-PV myelofibrosis in human myeloproliferative neoplasms. In aggregate, these results demonstrate the distinct roles of LT-HSCs and erythroid precursors in the pathogenesis of PV.