ABSTRACT
Genomic analyses of cutaneous melanoma (CM) have yielded biological and therapeutic insights, but understanding of non-ultraviolet (UV)-derived CMs remains limited. Deeper analysis of acral lentiginous melanoma (ALM), a rare sun-shielded melanoma subtype associated with worse survival than CM, is needed to delineate non-UV oncogenic mechanisms. We thus performed comprehensive genomic and transcriptomic analysis of 34 ALM patients. Unlike CM, somatic alterations were dominated by structural variation and absence of UV-derived mutation signatures. Only 38% of patients demonstrated driver BRAF/NRAS/NF1 mutations. In contrast with CM, we observed PAK1 copy gains in 15% of patients, and somatic TERT translocations, copy gains, and missense and promoter mutations, or germline events, in 41% of patients. We further show that in vitro TERT inhibition has cytotoxic effects on primary ALM cells. These findings provide insight into the role of TERT in ALM tumorigenesis and reveal preliminary evidence that TERT inhibition represents a potential therapeutic strategy in ALM.
Subject(s)
Chromosome Aberrations , Melanoma/genetics , Mutation , Skin Neoplasms/genetics , Telomerase/genetics , Adult , Aged , Aged, 80 and over , Cells, Cultured , Female , GTP Phosphohydrolases/genetics , Genes, Neurofibromatosis 1 , Humans , Male , Melanoma/pathology , Membrane Proteins/genetics , Middle Aged , Proto-Oncogene Proteins B-raf/genetics , Skin Neoplasms/pathology , Telomerase/metabolism , Transcriptome , p21-Activated Kinases/geneticsABSTRACT
Malignant melanoma (MM) exhibits a high propensity for central nervous system dissemination with ~50% of metastatic MM patients developing brain metastases (BM). Targeted therapies and immune checkpoint inhibitors have improved overall survival for MM patients with BM. However, responses are usually of short duration and new agents that effectively penetrate the blood brain barrier (BBB) are needed. Here, we report a MM patient with BM who experienced an exceptional response to E6201, an ATP-competitive MEK1 inhibitor, on a Phase 1 study, with ongoing near-complete response and overall survival extending beyond 8 years. Whole exome and transcriptome sequencing revealed a high mutational burden tumor (22 mutations/Megabase) with homozygous BRAF V600E mutation. Correlative preclinical studies demonstrated broad activity for E6201 across BRAF V600E mutant melanoma cell lines and effective BBB penetration in vivo. Together, these results suggest that E6201 may represent a potential new treatment option for BRAF-mutant MM patients with BM.
Subject(s)
Antineoplastic Agents/therapeutic use , Brain Neoplasms/drug therapy , Lactones/therapeutic use , Melanoma/drug therapy , Protein Kinase Inhibitors/therapeutic use , Proto-Oncogene Proteins B-raf/genetics , Skin Neoplasms/drug therapy , Aged, 80 and over , Animals , Antineoplastic Agents/blood , Antineoplastic Agents/pharmacokinetics , Brain/metabolism , Brain Neoplasms/genetics , Brain Neoplasms/metabolism , Brain Neoplasms/secondary , Cell Line, Tumor , Female , Gene Expression Profiling , Humans , Lactones/blood , Lactones/pharmacokinetics , Male , Melanoma/genetics , Melanoma/metabolism , Melanoma/pathology , Mice, Knockout , Mutation , Protein Kinase Inhibitors/blood , Protein Kinase Inhibitors/pharmacokinetics , Skin Neoplasms/genetics , Skin Neoplasms/metabolism , Skin Neoplasms/pathology , Treatment Outcome , Exome SequencingABSTRACT
BACKGROUND: Circular RNAs (circRNAs) are a novel class of endogenous, non-coding RNAs that form covalently closed continuous loops and that are both highly conserved and abundant in the mammalian brain. A role for circRNAs in sponging microRNAs (miRNAs) has been proposed, but the circRNA-miRNA-mRNA interaction networks in human brain cells have not been defined. Therefore, we identified circRNAs in RNA sequencing data previously generated from astrocytes microdissected from the posterior cingulate (PC) of Alzheimer's disease (AD) patients (N = 10) and healthy elderly controls (N = 10) using four circRNA prediction algorithms - CIRI, CIRCexplorer, find_circ and KNIFE. RESULTS: Overall, utilizing these four tools, we identified a union of 4438 unique circRNAs across all samples, of which 70.3% were derived from exonic regions. Notably, the widely reported CDR1as circRNA was detected in all samples across both groups by find_circ. Given the putative miRNA regulatory function of circRNAs, we identified potential miRNA targets of circRNAs, and further, delineated circRNA-miRNA-mRNA networks using in silico methods. Pathway analysis of the genes regulated by these miRNAs identified significantly enriched immune response pathways, which is consistent with the known function of astrocytes as immune sensors in the brain. CONCLUSIONS: In this study, we performed circRNA detection on cell-specific transcriptomic data and identified potential circRNA-miRNA-mRNA regulatory networks in PC astrocytes. Given the known function of astrocytes in cerebral innate immunity and our identification of significantly enriched immune response pathways, the circRNAs we identified may be associated with such key functions. While we did not detect recurrent differentially expressed circRNAs in the context of healthy controls or AD, we report for the first time circRNAs and their potential regulatory impact in a cell-specific and region-specific manner in aged subjects. These predicted regulatory network and pathway analyses may help provide new insights into transcriptional regulation in the brain.
Subject(s)
Alzheimer Disease/genetics , Astrocytes/metabolism , Gene Regulatory Networks , Genetic Markers , Gyrus Cinguli/metabolism , RNA/genetics , Aged , Alzheimer Disease/pathology , Astrocytes/cytology , Case-Control Studies , Cells, Cultured , Female , Gyrus Cinguli/cytology , High-Throughput Nucleotide Sequencing , Humans , Male , MicroRNAs/genetics , RNA, Circular , RNA, Messenger/geneticsABSTRACT
BACKGROUND: Joubert syndrome (JS) is a recessive ciliopathy characterised by a distinctive brain malformation 'the molar tooth sign'. Mutations in >27 genes cause JS, and mutations in 12 of these genes also cause Meckel-Gruber syndrome (MKS). The goals of this work are to describe the clinical features of MKS1-related JS and determine whether disease causing MKS1 mutations affect cellular phenotypes such as cilium number, length and protein content as potential mechanisms underlying JS. METHODS: We measured cilium number, length and protein content (ARL13B and INPP5E) by immunofluorescence in fibroblasts from individuals with MKS1-related JS and in a three-dimensional (3D) spheroid rescue assay to test the effects of disease-related MKS1 mutations. RESULTS: We report MKS1 mutations (eight of them previously unreported) in nine individuals with JS. A minority of the individuals with MKS1-related JS have MKS features. In contrast to the truncating mutations associated with MKS, all of the individuals with MKS1-related JS carry ≥ 1 non-truncating mutation. Fibroblasts from individuals with MKS1-related JS make normal or fewer cilia than control fibroblasts, their cilia are more variable in length than controls, and show decreased ciliary ARL13B and INPP5E. Additionally, MKS1 mutant alleles have similar effects in 3D spheroids. CONCLUSIONS: MKS1 functions in the transition zone at the base of the cilium to regulate ciliary INPP5E content, through an ARL13B-dependent mechanism. Mutations in INPP5E also cause JS, so our findings in patient fibroblasts support the notion that loss of INPP5E function, due to either mutation or mislocalisation, is a key mechanism underlying JS, downstream of MKS1 and ARL13B.
Subject(s)
Abnormalities, Multiple/genetics , Abnormalities, Multiple/metabolism , Cerebellum/abnormalities , Cilia/genetics , Cilia/metabolism , Eye Abnormalities/genetics , Eye Abnormalities/metabolism , Kidney Diseases, Cystic/genetics , Kidney Diseases, Cystic/metabolism , Phosphoric Monoester Hydrolases/metabolism , Proteins/genetics , Proteins/metabolism , Retina/abnormalities , ADP-Ribosylation Factors/metabolism , Abnormalities, Multiple/diagnosis , Animals , Brain/pathology , Cells, Cultured , Cerebellum/metabolism , Cilia/pathology , Exons , Eye Abnormalities/diagnosis , Fibroblasts/metabolism , Fibroblasts/pathology , Gene Expression Regulation , Humans , Kidney Diseases, Cystic/diagnosis , Magnetic Resonance Imaging , Mice , Models, Biological , Mutation , Protein Binding , Protein Transport , Retina/metabolism , Tomography, X-Ray ComputedABSTRACT
Advanced cholangiocarcinoma continues to harbor a difficult prognosis and therapeutic options have been limited. During the course of a clinical trial of whole genomic sequencing seeking druggable targets, we examined six patients with advanced cholangiocarcinoma. Integrated genome-wide and whole transcriptome sequence analyses were performed on tumors from six patients with advanced, sporadic intrahepatic cholangiocarcinoma (SIC) to identify potential therapeutically actionable events. Among the somatic events captured in our analysis, we uncovered two novel therapeutically relevant genomic contexts that when acted upon, resulted in preliminary evidence of anti-tumor activity. Genome-wide structural analysis of sequence data revealed recurrent translocation events involving the FGFR2 locus in three of six assessed patients. These observations and supporting evidence triggered the use of FGFR inhibitors in these patients. In one example, preliminary anti-tumor activity of pazopanib (in vitro FGFR2 IC50≈350 nM) was noted in a patient with an FGFR2-TACC3 fusion. After progression on pazopanib, the same patient also had stable disease on ponatinib, a pan-FGFR inhibitor (in vitro, FGFR2 IC50≈8 nM). In an independent non-FGFR2 translocation patient, exome and transcriptome analysis revealed an allele specific somatic nonsense mutation (E384X) in ERRFI1, a direct negative regulator of EGFR activation. Rapid and robust disease regression was noted in this ERRFI1 inactivated tumor when treated with erlotinib, an EGFR kinase inhibitor. FGFR2 fusions and ERRFI mutations may represent novel targets in sporadic intrahepatic cholangiocarcinoma and trials should be characterized in larger cohorts of patients with these aberrations.
Subject(s)
Bile Duct Neoplasms/drug therapy , Cholangiocarcinoma/drug therapy , ErbB Receptors/metabolism , Receptor, Fibroblast Growth Factor, Type 2/genetics , Signal Transduction/genetics , Bile Duct Neoplasms/genetics , Bile Duct Neoplasms/pathology , Bile Ducts, Intrahepatic/pathology , Cell Line, Tumor , Cholangiocarcinoma/genetics , Cholangiocarcinoma/pathology , ErbB Receptors/antagonists & inhibitors , ErbB Receptors/genetics , Erlotinib Hydrochloride , Genome, Human , Humans , Imidazoles/administration & dosage , Indazoles , Molecular Targeted Therapy , Mutation , Prognosis , Protein Kinase Inhibitors , Pyridazines/administration & dosage , Pyrimidines/administration & dosage , Quinazolines/administration & dosage , Receptor, Fibroblast Growth Factor, Type 2/antagonists & inhibitors , Receptor, Fibroblast Growth Factor, Type 2/metabolism , Sulfonamides/administration & dosage , TranscriptomeABSTRACT
Joubert syndrome related disorders (JSRDs) have broad but variable phenotypic overlap with other ciliopathies. The molecular etiology of this overlap is unclear but probably arises from disrupting common functional module components within primary cilia. To identify additional module elements associated with JSRDs, we performed homozygosity mapping followed by next-generation sequencing (NGS) and uncovered mutations in TMEM237 (previously known as ALS2CR4). We show that loss of the mammalian TMEM237, which localizes to the ciliary transition zone (TZ), results in defective ciliogenesis and deregulation of Wnt signaling. Furthermore, disruption of Danio rerio (zebrafish) tmem237 expression produces gastrulation defects consistent with ciliary dysfunction, and Caenorhabditis elegans jbts-14 genetically interacts with nphp-4, encoding another TZ protein, to control basal body-TZ anchoring to the membrane and ciliogenesis. Both mammalian and C. elegans TMEM237/JBTS-14 require RPGRIP1L/MKS5 for proper TZ localization, and we demonstrate additional functional interactions between C. elegans JBTS-14 and MKS-2/TMEM216, MKSR-1/B9D1, and MKSR-2/B9D2. Collectively, our findings integrate TMEM237/JBTS-14 in a complex interaction network of TZ-associated proteins and reveal a growing contribution of a TZ functional module to the spectrum of ciliopathy phenotypes.
Subject(s)
Cerebellar Diseases/genetics , Cilia/genetics , Eye Abnormalities/genetics , Kidney Diseases, Cystic/genetics , Membrane Proteins/genetics , Mutation , Abnormalities, Multiple , Adult , Animals , Bardet-Biedl Syndrome/genetics , Caenorhabditis elegans/genetics , Caenorhabditis elegans/ultrastructure , Case-Control Studies , Cell Line , Cerebellum/abnormalities , Child , Child, Preschool , Chromosome Mapping , Cilia/metabolism , Female , Gene Expression , Gene Knockdown Techniques , Gene Knockout Techniques , Genetic Association Studies , Haplotypes , Humans , Infant , Infant, Newborn , Male , Membrane Proteins/metabolism , Mice , Microscopy, Electron, Transmission , Multiprotein Complexes/metabolism , Polymorphism, Single Nucleotide , Retina/abnormalities , Sequence Analysis, DNA , Wnt Proteins/metabolism , Wnt Signaling Pathway , Zebrafish/embryology , Zebrafish/geneticsABSTRACT
A genomic understanding of the oncogenic processes and individual variability of human cancer has steadily fueled improvement in patient outcomes over the past 20 years. Mutations within tumour tissues are routinely assessed through clinical genomic diagnostic assays by academic and commercial laboratories to facilitate diagnosis, prognosis and effective treatment stratification. The application of genomics has unveiled a wealth of mutation-based biomarkers in canine cancers, suggesting that the transformative principles that have revolutionized human cancer medicine can be brought to bear in veterinary oncology. To advance clinical genomics and genomics-guided medicine in canine oncology, we have developed and validated a canine cancer next-generation sequencing gene panel for the identification of multiple mutation types in clinical specimens. With this panel, we examined the genomic landscapes of 828 tumours from 813 dogs, spanning 53 cancer types. We identified 7856 alterations, encompassing copy number variants, single nucleotide variants, indels and internal tandem duplications. Additionally, we evaluated the clinical utility of these alterations by incorporating a biomarker framework from comprehensive curation of primary canine literature and inferences from human cancer genomic biomarker literature and clinical diagnostics. Remarkably, nearly 90% of the cases exhibited mutations with diagnostic, prognostic or therapeutic implications. Our work represents a thorough assessment of genomic landscapes in a large cohort of canine cancers, the first of its kind for its comprehensive inclusion of multiple mutation types and structured annotation of biomarkers, demonstrating the clinical potential of leveraging mutation-based biomarkers in veterinary oncology.
Subject(s)
Dog Diseases , Neoplasms , Dogs , Humans , Animals , Dog Diseases/genetics , Neoplasms/genetics , Neoplasms/veterinary , Genomics , Mutation , Biomarkers, Tumor/geneticsABSTRACT
Multiple myeloma is a treatable, but currently incurable, hematological malignancy of plasma cells characterized by diverse and complex tumor genetics for which precision medicine approaches to treatment are lacking. The Multiple Myeloma Research Foundation's Relating Clinical Outcomes in Multiple Myeloma to Personal Assessment of Genetic Profile study ( NCT01454297 ) is a longitudinal, observational clinical study of newly diagnosed patients with multiple myeloma (n = 1,143) where tumor samples are characterized using whole-genome sequencing, whole-exome sequencing and RNA sequencing at diagnosis and progression, and clinical data are collected every 3 months. Analyses of the baseline cohort identified genes that are the target of recurrent gain-of-function and loss-of-function events. Consensus clustering identified 8 and 12 unique copy number and expression subtypes of myeloma, respectively, identifying high-risk genetic subtypes and elucidating many of the molecular underpinnings of these unique biological groups. Analysis of serial samples showed that 25.5% of patients transition to a high-risk expression subtype at progression. We observed robust expression of immunotherapy targets in this subtype, suggesting a potential therapeutic option.
Subject(s)
DNA Copy Number Variations , Multiple Myeloma , Humans , Multiple Myeloma/genetics , Gene Expression Regulation, Neoplastic , Exome Sequencing , Gene Expression Profiling , Female , Male , Whole Genome Sequencing , Longitudinal Studies , Disease Progression , Middle AgedABSTRACT
BACKGROUND: Joubert syndrome (JS) is a ciliopathy characterised by a distinctive brain malformation (the 'molar tooth sign'), developmental delay, abnormal eye movements and abnormal breathing pattern. Retinal dystrophy, cystic kidney disease, liver fibrosis and polydactyly are variably present, resulting in significant phenotypic heterogeneity and overlap with other ciliopathies. JS is also genetically heterogeneous, resulting from mutations in 13 genes. These factors render clinical/molecular diagnosis and management challenging. CC2D2A mutations are a relatively common cause of JS and also cause Meckel syndrome. The clinical consequences of CC2D2A mutations in patients with JS have been incompletely reported. METHODS: Subjects with JS from 209 families were evaluated to identify mutations in CC2D2A. Clinical and imaging features in subjects with CC2D2A mutations were compared with those in subjects without CC2D2A mutations and reports in the literature. RESULTS: 10 novel CC2D2A mutations in 20 subjects were identified; a summary is provided of all published CC2D2A mutations. Subjects with CC2D2A-related JS were more likely to have ventriculomegaly (p<0.0001) and seizures (p=0.024) than subjects without CC2D2A mutations. No mutation-specific genotype-phenotype correlations could be identified, but the findings confirm the observation that mutations that cause CC2D2A-related JS are predicted to be less deleterious than mutations that cause CC2D2A-related Meckel syndrome. Missense variants in the coiled-coil and C2 domains, as well as the C-terminal region, identify these regions as important for the biological mechanisms underlying JS. CONCLUSIONS: CC2D2A testing should be prioritised in patients with JS and ventriculomegaly and/or seizures. Patients with CC2D2A-related JS should be monitored for hydrocephalus and seizures.
Subject(s)
Cerebellar Diseases/genetics , Eye Abnormalities/genetics , Genetic Association Studies , Hydrocephalus/genetics , Kidney Diseases, Cystic/genetics , Proteins/genetics , Seizures/genetics , Abnormalities, Multiple , Adolescent , Adult , Alleles , Cerebellar Diseases/diagnosis , Cerebellar Diseases/epidemiology , Cerebellum/abnormalities , Child , Child, Preschool , Cytoskeletal Proteins , Eye Abnormalities/diagnosis , Eye Abnormalities/epidemiology , Genotype , Humans , Hydrocephalus/diagnosis , Infant , Kidney Diseases, Cystic/diagnosis , Kidney Diseases, Cystic/epidemiology , Magnetic Resonance Imaging , Neuroimaging , Phenotype , Prevalence , Retina/abnormalities , Young AdultABSTRACT
OBJECTIVE: To evaluate the diagnostic, prognostic, and therapeutic utility of a cancer genomic diagnostic assay (SearchLight DNA; Vidium Animal Health) for diagnostically ambiguous cancer cases. ANIMALS: 69 privately owned dogs with ambiguous cancer diagnoses and for which the genomic assay was performed. PROCEDURES: Genomic assay reports generated between September 28, 2020, and July 31, 2022, for dogs with malignancy or suspected malignancy were reviewed to determine the assay's clinical utility defined as providing diagnostic clarity, prognostic information, and/or therapeutic options. RESULTS: Genomic analysis provided diagnostic clarity in 37 of 69 cases (54%; group 1) and therapeutic and/or prognostic information in 22 of the remaining 32 cases (69%; group 2) for which the diagnosis remained elusive. Overall, the genomic assay was clinically useful in 86% (59/69) of cases. CLINICAL RELEVANCE: To our knowledge, this was the first study to evaluate the multifaceted clinical utility of a single cancer genomic test in veterinary medicine. Study findings supported the use of tumor genomic testing for dogs with cancer, particularly those that are diagnostically ambiguous and therefore inherently challenging to manage. This evidence-driven genomic assay provided diagnostic guidance, prognostic support, and therapeutic options for most patients with an unclear cancer diagnosis that would otherwise have an unsubstantiated clinical plan. Furthermore, 38% (26/69) of samples were easily obtained aspirates. Sample factors (sample type, percentage of tumor cells, and number of mutations) did not influence diagnostic yield. Our study demonstrated the value of genomic testing for the management of canine cancer.
Subject(s)
Dog Diseases , Neoplasms , Dogs , Animals , Neoplasms/diagnosis , Neoplasms/genetics , Neoplasms/therapy , Neoplasms/veterinary , Genomics , Dog Diseases/diagnosis , Dog Diseases/genetics , Dog Diseases/therapyABSTRACT
Joubert syndrome (JS) is an autosomal recessive ciliopathy characterized by hypotonia, ataxia, abnormal eye movements, and intellectual disability. The brain is malformed, with severe vermian hypoplasia, fourth ventriculomegaly, and "molar tooth" appearance of the cerebral and superior cerebellar peduncles visible as consistent features on neuroimaging. Neuropathological studies, though few, suggest that several other brain and spinal cord structures, such as the dorsal cervicomedullary junction, may also be affected in at least some patients. Genetically, JS is heterogeneous, with mutations in 13 genes accounting for approximately 50% of patients. Here, we compare neuropathologic findings in five subjects with JS, including four with defined mutations in OFD1 (2 siblings), RPGRIP1L, or TCTN2. Characteristic findings in all JS genotypes included vermian hypoplasia, fragmented dentate and spinal trigeminal nuclei, hypoplastic pontine and inferior olivary nuclei, and nondecussation of corticospinal tracts. Other common findings, seen in multiple genotypes but not all subjects, were dorsal cervicomedullary heterotopia, nondecussation of superior cerebellar peduncles, enlarged arcuate nuclei, hypoplastic reticular formation, hypoplastic medial lemnisci, and dorsal spinal cord disorganization. Thus, while JS exhibits significant neuropathologic as well as genetic heterogeneity, no genotype-phenotype correlations are apparent as yet. Our findings suggest that primary cilia are important for neural patterning, progenitor proliferation, cell migration, and axon guidance in the developing human brain and spinal cord.
Subject(s)
Abnormalities, Multiple/pathology , Brain/abnormalities , Cerebellar Diseases/pathology , Cilia/pathology , Eye Abnormalities/pathology , Kidney Diseases/pathology , Spinal Cord/abnormalities , Cell Movement , Cell Proliferation , Cerebellar Diseases/complications , Cerebellar Diseases/genetics , Eye Abnormalities/complications , Eye Abnormalities/genetics , Female , Fetus , Genotype , Humans , Intellectual Disability , Kidney Diseases/complications , Male , NeuroimagingABSTRACT
Although combination BRAF and MEK inhibitors are highly effective for the 40-50% of cutaneous metastatic melanomas harboring BRAFV600 mutations, targeted agents have been ineffective for BRAFV600wild-type (wt) metastatic melanomas. The SU2C Genomics-Enabled Medicine for Melanoma Trial utilized a Simon two-stage optimal design to assess whether comprehensive genomic profiling improves selection of molecular-based therapies for BRAFV600wt metastatic melanoma patients who had progressed on standard-of-care therapy, which may include immunotherapy. Of the response-evaluable patients, binimetinib was selected for 20 patients randomized to the genomics-enabled arm, and nine were treated on the alternate treatment arm. Response rates for 27 patients treated with targeted recommendations included one (4%) partial response, 18 (67%) with stable disease, and eight (30%) with progressive disease. Post-trial genomic and protein pathway activation mapping identified additional drug classes that may be considered for future studies. Our results highlight the complexity and heterogeneity of metastatic melanomas, as well as how the lack of response in this trial may be associated with limitations including monotherapy drug selection and the dearth of available single and combination molecularly-driven therapies to treat BRAFV600wt metastatic melanomas.
Subject(s)
Benzimidazoles/administration & dosage , Genomics , Melanoma , Proto-Oncogene Proteins B-raf , Skin Neoplasms , Adult , Aged , Female , Humans , Male , Melanoma/drug therapy , Melanoma/genetics , Melanoma/metabolism , Middle Aged , Neoplasm Metastasis , Pilot Projects , Prospective Studies , Proto-Oncogene Proteins B-raf/genetics , Proto-Oncogene Proteins B-raf/metabolism , Skin Neoplasms/drug therapy , Skin Neoplasms/genetics , Skin Neoplasms/metabolism , Melanoma, Cutaneous MalignantABSTRACT
Circular RNAs (circRNAs) are evolutionarily conserved RNA species that are formed when exons "back-splice" to each other. Current computational algorithms to detect these back-splicing junctions produce divergent results, and hence there is a need for a method to distinguish true-positive circRNAs. To this end, we developed Assembly based CircRNA Validator (ACValidator) for in silico verification of circRNAs. ACValidator extracts reads from a user-defined window on either side of a circRNA junction and assembles them to generate contigs. These contigs are aligned against the circRNA sequence to find contigs spanning the back-spliced junction. When evaluated on simulated datasets, ACValidator achieved over â¼80% sensitivity on datasets with an average of 10 circRNA-supporting reads and with read lengths of at least 100 bp. In experimental datasets, ACValidator produced higher verification percentages for samples treated with ribonuclease R compared to nontreated samples. Our workflow is applicable to non-polyA-selected RNAseq datasets and can also be used as a candidate selection strategy for prioritizing experimental validations. All workflow scripts are freely accessible on our GitHub page https://github.com/tgen/ACValidator along with detailed instructions to set up and run ACValidator.
ABSTRACT
Archival tumor samples represent a rich resource of annotated specimens for translational genomics research. However, standard variant calling approaches require a matched normal sample from the same individual, which is often not available in the retrospective setting, making it difficult to distinguish between true somatic variants and individual-specific germline variants. Archival sections often contain adjacent normal tissue, but this tissue can include infiltrating tumor cells. As existing comparative somatic variant callers are designed to exclude variants present in the normal sample, a novel approach is required to leverage adjacent normal tissue with infiltrating tumor cells for somatic variant calling. Here we present lumosVar 2.0, a software package designed to jointly analyze multiple samples from the same patient, built upon our previous single sample tumor only variant caller lumosVar 1.0. The approach assumes that the allelic fraction of somatic variants and germline variants follow different patterns as tumor content and copy number state change. lumosVar 2.0 estimates allele specific copy number and tumor sample fractions from the data, and uses a to model to determine expected allelic fractions for somatic and germline variants and to classify variants accordingly. To evaluate the utility of lumosVar 2.0 to jointly call somatic variants with tumor and adjacent normal samples, we used a glioblastoma dataset with matched high and low tumor content and germline whole exome sequencing data (for true somatic variants) available for each patient. Both sensitivity and positive predictive value were improved when analyzing the high tumor and low tumor samples jointly compared to analyzing the samples individually or in-silico pooling of the two samples. Finally, we applied this approach to a set of breast and prostate archival tumor samples for which tumor blocks containing adjacent normal tissue were available for sequencing. Joint analysis using lumosVar 2.0 detected several variants, including known cancer hotspot mutations that were not detected by standard somatic variant calling tools using the adjacent tissue as presumed normal reference. Together, these results demonstrate the utility of leveraging paired tissue samples to improve somatic variant calling when a constitutional sample is not available.
ABSTRACT
Glioma is recognized to be a highly heterogeneous CNS malignancy, whose diverse cellular composition and cellular interactions have not been well characterized. To gain new clinical- and biological-insights into the genetically-bifurcated IDH1 mutant (mt) vs wildtype (wt) forms of glioma, we integrated data from protein, genomic and MR imaging from 20 treatment-naïve glioma cases and 16 recurrent GBM cases. Multiplexed immunofluorescence (MxIF) was used to generate single cell data for 43 protein markers representing all cancer hallmarks, Genomic sequencing (exome and RNA (normal and tumor) and magnetic resonance imaging (MRI) quantitative features (protocols were T1-post, FLAIR and ADC) from whole tumor, peritumoral edema and enhancing core vs equivalent normal region were also collected from patients. Based on MxIF analysis, 85,767 cells (glioma cases) and 56,304 cells (GBM cases) were used to generate cell-level data for 24 biomarkers. K-means clustering was used to generate 7 distinct groups of cells with divergent biomarker profiles and deconvolution was used to assign RNA data into three classes. Spatial and molecular heterogeneity metrics were generated for the cell data. All features were compared between IDH mt and IDHwt patients and were finally combined to provide a holistic/integrated comparison. Protein expression by hallmark was generally lower in the IDHmt vs wt patients. Molecular and spatial heterogeneity scores for angiogenesis and cell invasion also differed between IDHmt and wt gliomas irrespective of prior treatment and tumor grade; these differences also persisted in the MR imaging features of peritumoral edema and contrast enhancement volumes. A coherent picture of enhanced angiogenesis in IDHwt tumors was derived from multiple platforms (genomic, proteomic and imaging) and scales from individual proteins to cell clusters and heterogeneity, as well as bulk tumor RNA and imaging features. Longer overall survival for IDH1mt glioma patients may reflect mutation-driven alterations in cellular, molecular, and spatial heterogeneity which manifest in discernable radiological manifestations.
Subject(s)
Glioma/genetics , Isocitrate Dehydrogenase/genetics , Adult , Aged , Biomarkers, Tumor/genetics , Brain Neoplasms/pathology , Case-Control Studies , Female , Fluorescent Antibody Technique/methods , Genetic Heterogeneity , Humans , Isocitrate Dehydrogenase/metabolism , Magnetic Resonance Imaging/methods , Male , Middle Aged , Mutation , Neoplasm Grading , Proteomics , Sequence Analysis, RNA/methods , Single-Cell Analysis , Exome Sequencing/methodsABSTRACT
With the rapid evolution of genomics technologies over the past decade, whole genome sequencing (WGS) has become an increasingly accessible tool in biomedical research. WGS applications include analysis of genomic DNA from single individuals, multiple related family members, and tumor/normal samples from the same patient in the context of oncology. A number of different modalities are available for performing WGS; this chapter focuses on wet lab library construction procedures for complex short insert WGS libraries using the KAPA Hyper Prep Kit (Kapa Biosystems), and includes a discussion of appropriate quality control measures for sequencing on the Illumina HiSeq2000 platform. Additional modifications to the protocol for long insert WGS library construction, to assess structural alterations and copy number changes, are also described.
Subject(s)
Gene Library , Genome, Human , High-Throughput Nucleotide Sequencing/instrumentation , High-Throughput Nucleotide Sequencing/methods , Animals , HumansABSTRACT
Whole exome sequencing (WES) is a DNA sequencing strategy that provides a survey of base substitutions across coding genomic locations and other regions of interest. As the coding portion of the genome encompasses only 1-2% of the entire genome, this approach represents a more cost-effective strategy to detect DNA alterations that may alter protein function, compared to whole genome sequencing. Although the research community has and is currently delineating the functional implications of sequence changes in noncoding regions of the genome, WES is a currently available assay that provides valuable information for both discovery research and precision medicine applications. In this chapter, we present a WES library preparation protocol using the KAPA Hyper Prep Kit with Agilent SureSelect Human All Exon V5+UTR probes that demonstrates high DNA-to-library conversion efficiency for sequencing on the Illumina HiSeq platform.
Subject(s)
DNA, Neoplasm/genetics , Exome , Gene Library , High-Throughput Nucleotide Sequencing/methods , Neoplasms , Polymerase Chain Reaction/methods , Animals , DNA, Neoplasm/metabolism , Humans , Neoplasms/genetics , Neoplasms/metabolism , Neoplasms/pathologyABSTRACT
Chordoma is a rare, orphan cancer arising from embryonal precursors of bone. Surgery and radiotherapy (RT) provide excellent local control, often at the price of significant morbidity because of the structures involved and the need for relatively high doses of RT; however, recurrence remains high. Although our understanding of the genetic changes that occur in chordoma is evolving rapidly, this knowledge has yet to translate into treatments. We performed comprehensive DNA (paired tumor/normal whole-exome and shallow whole-genome) and RNA (tumor whole-transcriptome) next-generation sequencing analyses of archival sacral and clivus chordoma specimens. Incorporation of transcriptomic data enabled the identification of gene overexpression and expressed DNA alterations, thus providing additional support for potential therapeutic targets. In three patients, we identified alterations that may be amenable to off-label FDA-approved treatments for other tumor types. These alterations include FGFR1 overexpression (ponatinib, pazopanib) and copy-number duplication of CDK4 (palbociclib) and ERBB3 (gefitinib). In a third patient, germline DNA demonstrated predicted pathogenic changes in CHEK2 and ATM, which may have predisposed the patient to developing chordoma at a young age and may also be associated with potential sensitivity to PARP inhibitors because of homologous recombination repair deficiency. Last, in the fourth patient, a missense mutation in IGF1R was identified, suggesting potential activity for investigational anti-IGF1R strategies. Our findings demonstrate that chordoma patients present with aberrations in overlapping pathways. These results provide support for targeting the IGF1R/FGFR/EGFR and CDK4/6 pathways as treatment strategies for chordoma patients. This study underscores the value of comprehensive genomic and transcriptomic analysis in the development of rational, individualized treatment plans for chordoma.
Subject(s)
Chordoma/genetics , Chordoma/therapy , Gene Expression Profiling/methods , Adult , Aged , Ataxia Telangiectasia Mutated Proteins/genetics , Checkpoint Kinase 2/genetics , Checkpoint Kinase 2/metabolism , Cyclin-Dependent Kinase 4/genetics , DNA-Binding Proteins , Female , Gefitinib , Genomics/methods , Humans , Male , Middle Aged , Mutation , Nuclear Proteins/genetics , Piperazines , Poly(ADP-ribose) Polymerase Inhibitors/therapeutic use , Protein Kinase Inhibitors , Pyridines , Receptor, ErbB-3/genetics , Receptor, Fibroblast Growth Factor, Type 1/genetics , Skull Base Neoplasms , Transcription Factors/genetics , TranscriptomeABSTRACT
Coronary artery disease (CAD) is the leading cause of death in American women. Screening mammograms are recommended for women starting at age 40 for the early detection of breast cancer. An additional benefit of this routine screening tool may be to detect breast arterial calcifications (BAC) as a possible sign of CAD. The purpose of this study was to determine further the relationship between mammographically detected BAC and CAD. The medical records of 44 women who had undergone coronary artery bypass grafting at our institution over 5 years were reviewed. These mammograms were examined for evidence of BAC. For all women included in the study, 18 of 44 (41%) had evidence of BAC on screening mammogram. This was statistically significant (P < 0.0001) compared with the prevalence of BAC reported in the general population in previous studies. Most were also overweight (61.1%), had hypertension (88.8%), and hypercholesterolemia (55.5%). This is the first study to look at the direct correlation between patients with known CAD requiring revascularization and BAC. Perhaps women with BAC seen on screening mammography should undergo further workup for CAD, with the potential benefit of early intervention.
Subject(s)
Breast Diseases/diagnostic imaging , Calcinosis/diagnostic imaging , Coronary Disease/diagnostic imaging , Mammography , Aged , Aged, 80 and over , Breast Diseases/epidemiology , Calcinosis/epidemiology , Coronary Artery Bypass , Coronary Disease/epidemiology , Female , Humans , Middle Aged , Prevalence , Retrospective Studies , Risk FactorsABSTRACT
Large-scale multiplexed identification of somatic alterations in cancer has become feasible with next generation sequencing (NGS). However, calibration of NGS somatic analysis tools has been hampered by a lack of tumor/normal reference standards. We thus performed paired PCR-free whole genome sequencing of a matched metastatic melanoma cell line (COLO829) and normal across three lineages and across separate institutions, with independent library preparations, sequencing, and analysis. We generated mean mapped coverages of 99X for COLO829 and 103X for the paired normal across three institutions. Results were combined with previously generated data allowing for comparison to a fourth lineage on earlier NGS technology. Aggregate variant detection led to the identification of consensus variants, including key events that represent hallmark mutation types including amplified BRAF V600E, a CDK2NA small deletion, a 12 kb PTEN deletion, and a dinucleotide TERT promoter substitution. Overall, common events include >35,000 point mutations, 446 small insertion/deletions, and >6,000 genes affected by copy number changes. We present this reference to the community as an initial standard for enabling quantitative evaluation of somatic mutation pipelines across institutions.