Search Results - EGA European Genome-Phenome Archive

Biallelic mutations in the ubiquitin ligase RFWD3 cause Fanconi anemia

The WD40-containing E3 ubiquitin ligase RFWD3 has been recently linked to the repair of DNA damage by Homologous Recombination (HR). Here we show that an RFWD3 mutation within the WD40 domain is connected to the genetic disease Fanconi anemia (FA). An individual revealed congenital abnormalities characteristic for FA. Cells from the patient, carrying the compound heterozygous mutations c.205_206dupCC and c.1916T>A in RFWD3, show increased sensitivity to DNA interstrand cross-linking agents in terms of increased chromosomal breakage, reduced survival and cell cycle arrest in G2 phase. The cellular phenotype is mirrored in genetically engineered human and avian cells by inactivation of RFWD3 or by introduction of the patient-derived missense mutation, and is rescued by expression of wildtype RFWD3 protein. HR is disrupted in RFWD3 mutant cells, caused by impaired relocation of mutant RFWD3 to chromatin and defective physical interaction with RPA. Rfwd3 knockout mice exhibit increased embryonic lethality, are sub-fertile, show ovarian and testicular atrophy and have a reduced life span in which they resemble other FA mouse models. Although mutation was detected in a single child with FA yet, we propose RFWD3 as a novel FA gene, FANCW, supported by cellular paradigm systems and an animal model.

Study EGAS00001002440

Hermansky-Pudlak syndrome type 1 causes impaired anti-microbial immunity through a pathogenic lipid metabolism-mTOR circuit

Mendelian diseases that present with immune-mediated disorders can provide insights into the molecular mechanisms that drive inflammation. Hermansky-Pudlak syndrome (HPS) types 1 and 4 are caused by defective vesicle trafficking involving the BLOC-3 complex. The presence of inflammatory complications such as Crohn’s disease-like inflammation and lung fibrosis in these patients remains enigmatic. Using mass cytometry we observe an augmented inflammatory monocyte compartment in HPS1 patient peripheral blood that may be associated with a TNF - and IL-1α-dominated cytokine dysregulation. HPS1 patient monocyte-derived macrophages express an inflammatory TNF-OSM mRNA gene signature and changes in lipid metabolism. Using stimulation experiments and lysosomal proteomics we show that defective lipid metabolism drives RAB32-dependent mTOR signaling, facilitated by the accumulation of mTOR on lysosomes. This pathogenic circuit translates into aberrant bacterial clearance, which can be rescued with mTORC1 inhibition. We reveal that a pathogenic lipid-mTOR signaling circuit acts as a metabolic checkpoint for defective anti-microbial activity. This mechanism may be relevant to the complex pathology of HPS1 patients featuring macrophage lipid accumulation, granuloma formation, defective anti-microbial activity and tissue inflammation. Lastly, this circuit may be present in a wider group of disorders with defective lipid metabolism and cholesterol accumulation.

Study EGAS00001005053

Interplay of somatic alterations and immune infiltration modulates response to PD-1 blockade in advanced clear cell RCC -- CA209-010

Immune checkpoint inhibitors targeting the PD-1 pathway have transformed the management of many advanced malignancies, including clear cell renal cell carcinoma (ccRCC), but the drivers and resistors of PD-1 response remain incompletely elucidated. Here, we analyzed 592 tumors collected from advanced ccRCC patients enrolled in prospective clinical trials of treatment with PD-1 blockade (or mTOR inhibition as control arm) by whole-exome and RNA-sequencing, integrated with immunofluorescence analysis, to define the somatic alteration landscape of late-stage ccRCC and to uncover the immunogenomic determinants of therapeutic response. While conventional genomic markers (tumor mutation burden, neoantigen load) and degree of CD8+ T cell infiltration were not associated with clinical response, we discovered numerous chromosomal alterations in advanced ccRCC associated with response or resistance to PD-1 blockade. These advanced tumors were highly CD8+ T cell infiltrated, with only 22% and 5% with an immune desert and immune excluded phenotype, respectively. Our analysis revealed that CD8+ infiltrated tumors are depleted of favorable PBRM1 mutations and are enriched for unfavorable chromosomal losses of 9p21.3 when compared to non-infiltrated tumors. These data demonstrate how the interplay of somatic alterations and immunophenotypes impacts therapeutic efficacy.

Study EGAS00001004291

A Protein Neddylation Inhibitor MLN4924 Suppresses Patient-Derived Glioblastoma Cells via Inhibition of ERK and AKT Signaling

Glioblastoma is a highly aggressive and lethal brain tumor, with limited treatment options. Abnormal activation of the neddylation pathway is observed in glioblastoma, and the NEDD8-activating enzyme (NAE) inhibitor, MLN4924 was previously shown to be effective in glioblastoma cell line models. However, its effect has not been tested in patient-derived glioblastoma stem cells. Immunohistochemistry and public data were analyzed to determine whether NEDD8 pathway proteins are important in glioblastoma development and patient survival. The effects of MLN4924 were evaluated in 4 glioblastoma cell lines and 15 patient-derived glioblastoma stem cells using high content analysis. Immunoblot analysis assessed the NEDD8 pathway proteins and biomarkers. Whole transcriptome analysis identified pathways associated with MLN4924 sensitivity. NAE1 and UBA3 levels increased in glioblastoma patients; high NEDD8 levels were associated with poor clinical outcomes. Glioblastoma cell lines and patient-derived stem cells were highly susceptible to MLN4924, while normal human astrocytes were resistant. Genomic analyses indicated that MLN4924 sensitive cells exhibited enrichment of ERK and AKT signaling. We verified that MLN4924 inhibits ERK and AKT phosphorylation in MLN4924 sensitive cells. Our findings suggest that patient-derived glioblastoma stem cells in the context of ERK and AKT activation are sensitive and highly regulated by neddylation inhibition.

Study EGAS00001004018

Hypoxia acts as an environmental cue for the human TRM differentiation program

Tissue-resident memory T-cells (TRM) provide frontline defense against infectious diseases and contribute to anti-tumor immunity; however, aside from the necessity of TGF-β, knowledge regarding TRM-inductive cues remains incomplete, particularly for human cells. Oxygen tension is an environmental cue that distinguishes peripheral tissues from the circulation and here, we demonstrate that differentiation of human CD8+ T-cells in the presence of hypoxia and TGF-β1 led to the development of a TRM phenotype, characterized by a greater than five-fold increase in CD69+CD103+ cells expressing human TRM hallmarks and enrichment for endogenous human TRM gene signatures, including increased adhesion molecule expression and decreased expression of genes involved in recirculation. Hypoxia and TGF-β1 synergized to produce a significantly larger population of TRM phenotype cells than either condition alone, and comparison of these cells from the individual and combination conditions revealed distinct phenotypic and transcriptional profiles, indicating a programming response to milieu rather than a mere expansion. Our findings identify a previously unreported cue for the TRM differentiation program and can enable facile generation of human TRM phenotype cells in vitro for basic studies and translational applications such as adoptive cellular therapy.

Study EGAS00001005286

To determine the mutational impact of the in vitro culture, clonal human adult and pluripotent stem cell lines were subjected to a second clonal step after 3 months of culture. These subclones were whole genome sequenced to identify all the mutations that accumulated during the 3 month culture period.

Genetic changes acquired during culture pose a potential risk for the successful application of stem cells. To assess the risk of in vitro expansion on mutation accumulation we have performed whole genome sequencing of clonally expanded human induced pluripotent stem cells (iPS cells) and adult stem cells (ASCs) to identify all mutations that accumulated over a fixed culture period. We find that ASCs acquire more single nucleotide variants (SNVs) and indels per population doubling than the iPS cells. When compared with ASCs, iPS cells are more vulnerable to mutations in genes and promoters. Mutational analysis revealed a clear in vitro induced mutational signature that is irrespective of stem cell type. This in vitro signature is characterized by C to G transversions that are probably caused by oxidative stress. Additionally, we observed stem cell specific mutational signatures and differences in transcriptional strand bias, indicating differential activity of DNA repair mechanisms between stem cell types in culture. In conclusion, in vitro culture induces mutation accumulation in iPS cells and ASCs. Culture under low-oxygen tension may help to reduce the number of culture-induced mutations.

Study EGAS00001002955

The Molecular Landscape of Asian Breast Cancers Reveals Clinically Relevant Population-Specific Differences

Molecular profiles of breast cancer have contributed to an improved understanding of the disease, enabled development of molecular prognostic signatures to guide treatment decisions and unveiled new or more accurate therapeutic options for breast cancer patients. However, the extent to which differences in genetic, environmental and lifestyle factors influence molecular profiles in different populations remains poorly characterised, as relatively few large-scale molecular studies of breast tumours in non-Caucasian populations have hitherto been reported. Here, we present the molecular profiles of 560 Asian breast tumours and a comparative analysis of breast cancers arising in Asian and Caucasian women. Compared to the breast tumours in predominantly Caucasian women reported in TCGA and METABRIC, we show an increased prevalence of Her2-enriched molecular subtypes and higher prevalence of TP53 somatic mutations in ER+ Asian breast tumours. Using gene expression and immunohistochemistry, we observed elevated immune scores in Asian breast tumours, suggesting potential clinical response to immune checkpoint inhibitors. Whilst Her2-subtype and enriched immune score are associated with improved survival, presence of TP53 somatic mutations is associated with poorer survival in ER+ tumours. Taken together, these population differences unveil new opportunities to improve the understanding of this disease and lay the foundation for precision medicine in different populations.

Study EGAS00001004518

Hermansky-Pudlak syndrome type 1 causes impaired anti-microbial immunity through a pathogenic lipid metabolism-mTOR circuit - 10x Genomics scRNAseq

Mendelian diseases that present with immune-mediated disorders can provide insights into the molecular mechanisms that drive inflammation. Hermansky-Pudlak syndrome (HPS) types 1 and 4 are caused by defective vesicle trafficking involving the BLOC-3 complex. The presence of inflammatory complications such as Crohn’s disease-like inflammation and lung fibrosis in these patients remains enigmatic. Using mass cytometry we observe an augmented inflammatory monocyte compartment in HPS1 patient peripheral blood that may be associated with a TNF - and IL-1α-dominated cytokine dysregulation. HPS1 patient monocyte-derived macrophages express an inflammatory TNF-OSM mRNA gene signature and changes in lipid metabolism. Using stimulation experiments and lysosomal proteomics we show that defective lipid metabolism drives RAB32-dependent mTOR signaling, facilitated by the accumulation of mTOR on lysosomes. This pathogenic circuit translates into aberrant bacterial clearance, which can be rescued with mTORC1 inhibition. We reveal that a pathogenic lipid-mTOR signaling circuit acts as a metabolic checkpoint for defective anti-microbial activity. This mechanism may be relevant to the complex pathology of HPS1 patients featuring macrophage lipid accumulation, granuloma formation, defective anti-microbial activity and tissue inflammation. Lastly, this circuit may be present in a wider group of disorders with defective lipid metabolism and cholesterol accumulation.

Study EGAS00001005098

Variation and transmission of the human gut microbiota across generations - shotgun data

Although composition and functional potential of the human gut microbiota evolve over lifespan, kinship has been identified as a key covariate of microbial community diversification. To date, sharing of microbiota features within families has however mostly been assessed between parents and their direct offspring. Here, we investigate potential transmission and persistence of familial microbiome patterns and microbial genotypes in a family cohort (N=102) spanning three to five generations over the same female bloodline. We observe microbiome community composition to be associated with kinship, with seven (low-abundant) genera displaying familial distribution patterns. While kinship and current cohabitation emerged as closely entangled variables, our explorative analyses of microbial genotype distribution and transmission estimates point at the latter as a key covariate of strain dissemination. Highest potential transmission rates are estimated between sisters and mother-daughter pairs, decreasing with increasing daughter’s age, and being higher among cohabiting pairs than those living apart. Although rare, we do detect potential transmission events spanning three and four generations, primarily involving species of the genera Alistipes and Bacteroides. Overall, while our analyses confirm the existence of family-bound microbiome community profiles, transmission or co-acquisition of bacterial strains appears to be strongly linked to cohabitation.

Study EGAS00001005649

Variation and transmission of the human gut microbiota across generations - 16S data

Although composition and functional potential of the human gut microbiota evolve over lifespan, kinship has been identified as a key covariate of microbial community diversification. To date, sharing of microbiota features within families has however mostly been assessed between parents and their direct offspring. Here, we investigate potential transmission and persistence of familial microbiome patterns and microbial genotypes in a family cohort (N=102) spanning three to five generations over the same female bloodline. We observe microbiome community composition to be associated with kinship, with seven (low-abundant) genera displaying familial distribution patterns. While kinship and current cohabitation emerged as closely entangled variables, our explorative analyses of microbial genotype distribution and transmission estimates point at the latter as a key covariate of strain dissemination. Highest potential transmission rates are estimated between sisters and mother-daughter pairs, decreasing with increasing daughter’s age, and being higher among cohabiting pairs than those living apart. Although rare, we do detect potential transmission events spanning three and four generations, primarily involving species of the genera Alistipes and Bacteroides. Overall, while our analyses confirm the existence of family-bound microbiome community profiles, transmission or co-acquisition of bacterial strains appears to be strongly linked to cohabitation.

Study EGAS00001005651

A recessive PRDM13 mutation results in congenital hypogonadotropic hypogonadism and cerebellar hypoplasia

The PRDM13 (PR Domain containing 13) putative chromatin modifier and transcriptional regulator functions downstream of the transcription factor PTF1A, which controls GABAergic fate in the spinal cord and neurogenesis in the hypothalamus. Here, we report a novel, recessive syndrome associated with PRDM13 mutation. Patients exhibited intellectual disability, ataxia with cerebellar hypoplasia, scoliosis and delayed puberty with congenital hypogonadotropic hypogonadism (CHH). Expression studies revealed Prdm13/PRDM13 transcripts in the developing hypothalamus and cerebellum in mouse and human. An analysis of hypothalamus and cerebellum development in mice homozygous for a Prdm13 mutant allele revealed a significant reduction in the number of Kisspeptin (Kiss1) neurons in the hypothalamus and PAX2+ progenitors emerging from the cerebellar ventricular zone. The latter was accompanied by ectopic expression of the glutamatergic lineage marker TLX3. Prdm13-deficient mice displayed cerebellar hypoplasia, normal gonadal structure, but delayed pubertal onset. Together, these findings identify PRDM13 as a critical regulator of GABAergic cell fate in the cerebellum and of hypothalamic kisspeptin neuron development, providing a mechanistic explanation for the co-occurrence of CHH and cerebellar hypoplasia in this syndrome. To our knowledge, this is the first evidence linking disrupted PRDM13-mediated regulation of Kiss1 neurons to CHH in humans.

Study EGAS00001005878

Sclerosing epithelioid fibrosarcoma case report

Sclerosing epithelioid fibrosarcoma (SEF) is a rare and aggressive soft tissue sarcomathought to originate in fibroblasts of the tissues surrounding tendons, ligaments and muscles. Minimally responsive to conventional cytotoxic chemotherapies, greater than 50% of SEF patients experience relapse and/or metastatic disease. SEF is most commonly discovered in middle-aged and elderly adults, but also rarely in children. A common gene fusion occurring between the EWSR1 and CREB3L1 genes has been observed in 80-90% of SEF cases. We describe here the youngest SEF patient reported to date (a 3-year-old Caucasian male) who presented with numerous bony and lung metastases. Additionally, we perform a comprehensive literature review of all SEF-related articles published since the disease was first characterized. The patient described in this report experienced persistent disease progression despite being heavily treated with multiple surgeries, radiation, numerous chemotherapies and targeted therapeutics. Primary tumor, metastatic and relapse sites were sequenced by whole genome, whole exome, and deep transcriptome next generation sequencing with comparison to a patient-matched normal blood sample. Consistent across all sequencing analyses was the disease-defining EWSR1-CREB3L1 fusion as a single feature consensus. We provide an analysis of our genomic findings and a discussion as to potential therapeutic strategies for SEF.

Study EGAS00001005215

Comprehensive Genomic Characterization of Refractory Multiple Myeloma Reveals a Complex Mutational and Structural Landscape Associated with Drug Resistance (H067)

Outcome of patients with multiple myeloma (MM) refractory to immunomodulatory agents (IMiDs) and proteasome inhibitors (PIs) is still very poor. To elucidate the genetic landscape of relapsed/refractory MM (RRMM) we performed whole genome and transcriptome sequencing of 39 heavily pretreated RRMM patients with at least double refractoriness revealing complex structural changes and a high mutational load (H067/K08K). We found a median of 67 structural variants and 116 nonsynonymous exonic mutations per patient. Assessment of oncogenic drivers showed NRAS, BRAF, TP53, KRAS, SLC4A7, FAM46C, DIS3, RB1, KMT2C, MLLT4, EWSR1, HCFC2, and COPS3 as significantly mutated. We found multiple genomic regions with bi-allelic events affecting known tumor suppressor genes, most frequently TP53, RB1, and TRAF3. Supervised analysis of mutational signatures showed a major contribution of Cosmic signature 6 associated with deficiency in DNA mismatch repair and the ‘BRCAness’ signature which coincided with mutations in genes known to confer PARP inhibitor sensitivity. Recurrently mutated gene networks included genes with relevance for PI and IMiD activity, the latter including in particular members of the Cereblon and the COP9 signalosome complex. In conclusion, this comprehensive genomic characterization revealed a complex mutational and structural landscape in RRMM and highlights potential implications for therapeutic strategies.

Study EGAS00001004363

tFL with a PMBL GE signature

We investigated the clinicopathologic features of 5 follicular lymphomas (FL) that transformed to morphologic diffuse large B-cell lymphomas (DLBCL) and had a primary mediastinal large B-cell lymphoma (PMBL)-like gene expression profile. None of the transformed FL (tFL) arose in the mediastinum, all cases tested had a germinal center B-cell immunophenotype, 20% were CD30+, 60% CD23+, 80% MAL+, 20% CD200+, and 0% CD273/PDL2+. Whole exome sequencing detected alterations in genes associated with both FL/DLBCL (CREBBP, KMT2C, KMT2D, ARID1A, HIST1 members, and TNFRSF14) and PMBL (JAK-STAT pathway genes, B2M, and CD58). Copy number (CN) analysis detected gains/amplification of REL in 60% and STAT6 in 40%, gains of chromosome 16, including IL4R, in 40%, and both deletions and gains of 11q in 20%. This cohort, although limited in size, supports a subset of tFL that has blended features between FL/DLBCL and PMBL. Despite having some features that are less common in DLBCL (MAL and CD23 expression, JAK-STAT activation), these cases lack the most characteristic CN alteration seen in PMBL (9p24.1 gain/amplification). This cohort expands the biologic heterogeneity of tFL, illustrating a subset with blended FL/DLBCL and PMBL features, with potential treatment implications that include the use of novel PMBL-targeted therapies.

Study EGAS00001005870

The malaria-protective human glycophorin structural variant DUP4 shows somatic mosaicism and association with hemoglobin levels

Glycophorin A and glycophorin B are red blood cell surface proteins that are both receptors for the parasite Plasmodium falciparum, which is the principal cause of malaria in sub-Saharan Africa. DUP4 is a complex structural genomic variant that carries extra copies of a glycophorin A - glycophorin B fusion gene, and has a dramatic effect on malaria risk by reducing the risk of severe malaria by up to 40% Using fiber-FISH and Illumina sequencing, we validate the structural arrangement of the glycophorin locus in the DUP4 variant, and reveal somatic variation in copy number of the glycophorin A- glycophorin B fusion gene. By developing a simple, specific, PCR-based assay for DUP4 we show the DUP4 variant reaches a frequency of 13% in a malaria-endemic village in south-eastern Tanzania. We genotype a substantial proportion of that village and demonstrate an association of DUP4 genotype with hemoglobin levels, a phenotype related to malaria, using a family-based association test. Taken together, we show that DUP4 is a complex structural variant that may be susceptible to somatic variation, and show that it is associated with a malarial-related phenotype in a non-hospitalizedlongitudinally-followed population.

Study EGAS00001003239

CRISPR/Cas9-mediated genome editing of Schistosoma mansoni acetylcholinesterase

Here we report successful gene knock-in (KI) in the eggs of Schistosoma mansoni by combining CRISPR/Cas9 with single-stranded oligodeoxynucleotides (ssODNs). We targeted the acetylcholinesterase (AChE) gene of S. mansoni using two synthetic guide RNAs (gRNAs), X5 and X7, respectively. Liver eggs of S. mansoni were exposed to CRISPR-vector containing X5 or X7 by electroporation. Simultaneously, eggs were transfected with a ssODN donor encoding a stop codon in all six frames. Next generation sequencing analysis revealed that CRISPR/Cas9-mediated editing in S. mansoni eggs resulted in Homology-Directed Repair (HDR) when template DNA ssODN provided. Furthermore, soluble egg antigen (SEA) from AChE-modified eggs exhibited markedly reduced AChE activity compared with controls, indicative that programmed Cas9 cleavage mutated the AChE gene. Following injection of modified schistosome eggs into the tail veins of mice, a significant decrease in granuloma size in the lungs of these animals. Notably, an enhanced Th2 response induced by eggs in lung, and splenocytes small intestine-draining mesenteric lymph node cells was also generated in mice injected with X5-KI eggs in different methods. These findings further demonstrate the power and utility of CRISPR/Cas9-based genome editing for undertaking functional genomics studies in schistosomes.

Study EGAS00001004455

Sex chromosome aneuploidies give rise to changes in the circular RNA profile

Purpose The landscape of circular RNAs (circRNAs), an important class of non-coding RNAs that regulate gene expression, has never been described in human disorders of sex chromosome aneuploidies. We profiled circRNAs in Turner syndrome females (45,X;TS) and Klinefelter syndrome males (47,XXY; KS) to investigate how circRNAs respond to a missing or an extra X chromosome. Methods Samples of blood, muscle and fat were collected from individuals with TS (n = 33) and KS (n = 22) and from male (n = 16) and female (n = 44) controls. CircRNAs were identified using a combination of circRNA identification pipelines (CIRI2, CIRCexplorer2 and circRNA_finder). Results Differential expression of circRNAs was observed throughout the genome in TS and KS, in all tissues. The host-genes from which several of these circRNAs were derived, were associated with known phenotypic traits. Furthermore, several differentially expressed circRNAs had the potential to capture micro RNAs that targeted protein-coding genes with altered expression in TS and KS. Conclusion Sex chromosome aneuploidies introduce pervasive changes in the circRNA transcriptome, demonstrating that the genomic changes in these syndromes are more complex than hitherto thought. CircRNAs may help explain some of the genomic and phenotypic traits observed in these syndromes.

Study EGAS00001006404

Stereotyped B-cell responses are linked to IgG constant region polymorphisms in multiple sclerosis

Clonally related B cells infiltrate the brain, meninges, and cerebrospinal fluid of multiple sclerosis (MS) patients, but the mechanisms driving the B-cell response and shaping the immunoglobulin repertoires remain unclear. Here, we used single-cell full-length RNA-seq and B-cell receptor reconstruction to simultaneously assess the phenotypes, isotypes, constant region polymorphisms, and the paired heavy- and light-chain repertoires in intrathecal B cells. We detected extensive clonal connections between the memory B cell and antibody-secreting cell compartments and observed clonally related cells of different isotypes, including IgM/IgG1, IgG1/IgA1, IgG1/IgG2, and IgM/IgA1. There was a strong dominance of the G1m1 allotype constant region polymorphisms in antibody-secreting cells, but not in memory B cells. Tightly linked to the G1m1 allotype, we found a preferential pairing of the immunoglobulin heavy-chain variable (IGHV)4 gene family with the κ variable (IGKV)1 gene family. The IGHV4-39 gene was most used and showed the highest frequency of pairing with IGKV1-5 and IGKV1(D)-33. These results link IgG constant region polymorphisms to stereotyped B-cell responses in MS and indicate that the intrathecal B-cell response in these patients could be directed against structurally similar epitopes.

Study EGAS00001005745

Regulatory T cell transcriptomic reprogramming characterizes adverse events by checkpoint inhibitors in solid tumors

Immune checkpoint inhibitors (ICI), which target immune regulatory pathways to unleash antitumor responses, have revolutionized cancer immunotherapy. Despite the remarkable success of ICI immunotherapy, a significant proportion of patients whose tumors respond to these treatments develop immune-related adverse events (irAEs) resembling autoimmune diseases. Although the clinical spectrum of irAEs is well characterized, their successful management remains empiric. This is in part because the pathogenic mechanisms involved in the break-down of peripheral tolerance and induction of irAEs remain elusive. Herein, we focused on regulatory T cells (Tregs) in individuals with irAEs because these cells are vital for maintenance of peripheral tolerance, appear expanded in the peripheral blood of individuals with cancer and abundantly express checkpoint molecules, hence representing direct targets of ICI immunotherapy. Our data demonstrate an intense transcriptomic reprogramming of CD4+CD25+CD127– Tregs in the blood of individuals with advanced metastatic melanoma who develop irAEs following ICI immunotherapy, with a characteristic inflammatory, apoptotic and metabolic signature. This inflammatory signature was shared by Tregs from individuals with different types of cancer developing irAEs and individuals with autoimmune diseases. Our findings propose an inflammatory Treg reprogramming as a feature of immunotherapy-induced irAEs, that may facilitate translational approaches aiming to induce robust antitumor immunity without disturbing peripheral tolerance.

Study EGAS00001004694

Clinical genome sequencing uncovers potentially targetable truncations and fusions of MAP3K8 in spitzoid and other melanomas

Spitzoid melanoma is a specific morphologic variant of melanoma that most commonly affects children and adolescents and ranges on the spectrum of malignancy from low-grade to overtly malignant. These tumors are generally driven by fusions of ALK, RET, NTRK1/3, MET, ROS1 and BRAF. However, in approximately 50% of cases, no genetic driver has been established. Clinical whole genome and transcriptome sequencing (RNA-Seq) of a spitzoid tumor from an adolescent revealed a novel gene fusion of MAP3K8, encoding a serine−threonine kinase that activates MEK. The patient who had exhausted all other therapeutic options was treated with a MEK inhibitor and underwent a transient clinical response. We subsequently analyzed spitzoid tumors from 49 patients by RNA-Seq and found in-frame fusions or C-terminal truncations in 33% of cases. The fusion transcripts and truncated genes all contained MAP3K8 exons 1-8 but lacked the autoinhibitory final exon. Data mining of RNA-Seq from the Cancer Genome Atlas (TCGA) uncovered analogous MAP3K8 rearrangements in 1.5% of adult melanomas. Thus, MAP3K8 rearrangements - uncovered by comprehensive clinical sequencing of a single case - are the most common genetic event in spitzoid melanoma, are present in adult melanomas, and could be amenable to MEK inhibition.

Study EGAS00001003430

Androgen receptor blockade promotes response to BRAF/MEK-targeted therapy

We studied a group of melanoma patients treated with neoadjuvant BRAF/MEK-targeted therapy (NCT02231775, n=51), and observed significantly higher rates of major pathologic response (MPR= <10% viable tumor at resection) and improved recurrence-free survival (RFS) in females versus males (MPR-66% versus 14%, p=0.001; RFS-64% versus 32% at 2 years, p=0.021). Findings were validated in a several additional cohorts 2-4 patients with unresectable metastatic melanoma treated with BRAF and/or MEK-targeted therapy (n=664 patients in total), demonstrating improved progression-free survival (PFS) and overall survival (OS) in females versus males in several of these studies. Studies in pre-clinical models demonstrated significantly impaired anti-tumor activity in male versus female BRAF/MEK-treated mice (p=0.006), with significantly higher expression of androgen receptor (AR) in tumors of male and female BRAF/MEK-treated mice versus control (p=0.0006 and 0.0025). Pharmacologic inhibition of AR signaling improved responses to BRAF/MEK-targeted therapy in male and female mice (p=0.018 and p=0.003), whereas induction of AR signaling (via testosterone administration) was associated with significantly impaired response to BRAF/MEK-targeted therapy in males and females (p=0.021 and p<0.0001).

Study EGAS00001006196

WXS and RNA-seq for 22 patients treated with radiation + immunotherapy

Over 500 active clinical trials are investigating combination radiation (RT) and immune checkpoint blockade (ICB) as a cancer treatment; however, the majority of trials have found no positive interaction. We performed a comprehensive molecular analysis of a randomized phase I clinical trial of patients with non-small cell lung cancer (NSCLC) treated with concurrent or sequential ablative RT and ICB. Concurrent treatment was superior to sequential treatment in augmenting local and distant tumor responses and improving overall survival in a subset of patients with highly aneuploid tumors, but not in those with less aneuploid tumors. Our analysis suggested that concurrent treatment eliminated immunologically cold aneuploid tumors better than sequential treatment and improved patient outcomes. In addition, we report that RT alone decreased intratumoral cytotoxic effector T cell and adaptive immune gene expression signatures, in contrast to upregulation of key immune pathways after concurrent administration of RT and ICB. Our findings distinguish the differential genomic and transcriptomic effects of RT versus RT and ICB and challenge the prevailing paradigm that local ablative RT beneficially stimulates the immune response. We propose the use of tumor aneuploidy as a novel biomarker and therapeutic target in personalizing treatment approaches for patients with NSCLC treated with RT and ICB.

Study EGAS00001006212

MutWP1__CRUK_Grand_Challenge_Mutographs_of_Cancer__clear_cell_renal_cell_carcinoma___2

The Mutographs project aims to advance our understanding of the causes of cancer through studies of mutational signatures. Led by Mike Stratton, together with Paul Brennan, Ludmil Alexandrov, Allan Balmain, David Phillips and Peter Campbell, this large-scale international research endeavour was awarded a Cancer Research UK Grand Challenge. Different patterns of somatic mutation are generated by the different environmental, lifestyle and genetic factors that cause cancer, many of them are still unknown. Within Mutographs, the International Agency for Research on Cancer is coordinating the recruitment of 5000 individuals with cancer (colorectal, renal, pancreatic, oesophageal adenocarcinoma or oesophageal squamous cancers) across 5 continents to explore whether different mutational signatures explain marked variation in incidence. In brief, through an international network of collaborators around the world, biological materials are collected, along with demographic, histological, clinical and questionnaire data. Whole genome sequences of tumour-germline DNA pairs are generated at the Wellcome Trust Sanger Institute. Somatic mutational signatures are subsequently extracted by non-negative matrix factorisation methods and correlated with risk factors data. Through an enhanced understanding of cancer aetiology, Mutographs unprecedented effort is anticipated to outline modifiable risk factors, lead to new approaches to prevent cancer, and provide opportunities to empower early detection, refine high-risk groups and contribute to further therapeutic development.

Study EGAS00001003542

Whole genome sequencing delineates regulatory, structural, and cryptic splice variants in early onset cardiomyopathy

Cardiomyopathy (CMP) is a heritable disorder. Over 50% cases are gene-elusive on clinical gene panel testing. The contribution of variants in non-coding DNA elements that result in cryptic splicing and regulate gene expression has not been explored. We analyzed whole genome sequencing (WGS) data in a discovery cohort of 209 pediatric CMP patients and 1,953 independent replication genomes and exomes. We searched for protein-coding variants, and non-coding variants predicted to affect the function or expression of genes. Thirty-nine % cases harbored pathogenic coding variants in known CMP genes, and 5% harbored high-risk loss-of-function (LoF) variants in additional candidate CMP genes. Fifteen % harbored high-risk regulatory variants in promoters and enhancers of CMP genes (Odds ratio 2.25, p=6.70×10-7 versus controls). Genes involved in α-dystroglycan glycosylation (FKTN, DTNA) and desmosomal signaling (DSC2, DSG2) were most highly enriched for regulatory variants (Odds ratio 6.7-58.1). Functional effects were confirmed in patient myocardium and reporter assays in human cardiomyocytes, and in zebrafish CRISPR knockouts. We provide strong evidence for the genomic contribution of functionally active variants in new genes and in regulatory elements of known CMP genes to early-onset CMP.

Study EGAS00001004929

Single-cell RNA sequencing reveals the mesangial identity and species diversity of glomerular cell transcriptomes

Molecular characterization of the individual cell types in human kidney as well as model organisms are critical in defining organ function and understanding translational aspects of biomedical research. Previous studies have uncovered gene expression profiles of several kidney glomerular cell types, however, important cells, including mesangial (MCs) and glomerular parietal epithelial cells (PECs), were missing or incompletely described, and a systematic comparison between mouse and human kidney is lacking. To this end, we used Smart-seq2 to profile 4332 individual glomerulus-associated cells isolated from human living donor renal biopsies and mouse kidney. The analysis revealed genetic programs for all four glomerular cell types (podocytes, glomerular endothelial cells, MCs and PECs) as well as rare glomerulus-associated macula densa cells (MDCs). Importantly, we detected heterogeneity in glomerulus-associated Pdgfrb-expressing cells, including bona fide intraglomerular MCs with the functionally active phagocytic molecular machinery, as well as a unique mural cell type located in the central stalk region of the glomerulus tuft. Furthermore, we observed remarkable species differences in the individual gene expression profiles of defined glomerular cell types that highlight translational challenges in the field and provide a guide to design translational studies.

Study EGAS00001004943

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