CASCADE metastatic melanoma study
Ontology highlight
ABSTRACT:
PROVIDER: EGAS00001004950 | EGA |
REPOSITORIES: EGA
Similar Datasets
Project description:Intratumoral heterogeneity (ITH) arises from distinct subclonal expansion following genetic or epigenetic alterations, and profoundly influences how tumors response to their immune microenvironment. Tumor progression trees based on single-cell mutational profiles have made it possible to trace subclonal evolution; however, conventional tree-building methods can incorporate only a limited number of cells and mutations, restricting their application to larger single-cell data. To investigate the effect of ITH on the therapeutic response of melanoma, we have developed Trisicell (https://trisicell.rtfd.io), a computational toolkit for scalable inference of mutational ITH through assessment of single-cell genomic variant data. By applying Trisicell to genetically matched mouse melanoma datasets, we found that expressed mutations are sufficient to effectively drive subclonal evolution. On single-cell, full-length RNA sequencing data of mouse melanoma from preclinical immune checkpoint blockade (ICB) studies, the analysis showed that the subtree-seeding mutations in the trees identified distinct subclones associated with a specific developmental state and neural crest lineage markers. Using the tree to trace cell lineages, we found that neoantigens depleted by ICB were predominantly expressed in minor subclones, suggesting that post-treatment recurrence is driven by immunoediting. Moreover, these neoantigens were enriched with those derived from frameshift mutations and mutated nuclear genes. Importantly, recurrently mutated genes in ICB-responding human melanoma exhibited the same features. We next used Trisicell to analyze single-cell, full-length RNA data of brain metastases (BM) from melanoma patients treated with ICB, and discovered that relapsing BM from ICB-responding patients exhibited subclones that also expressed a higher fraction of frameshift mutations and were associated with elevated levels of infiltrated T cells. Notably, they also exhibited more mutated HLA genes and expressed high level of the novel immune checkpoint HLA-G, a putative local immunosuppressive mechanism. In summary, applying Trisicell to single-cell transcriptomic analyses allowed us to identify novel features of ICB-responding melanoma neoantigens and distinct mechanisms for adapting to immunotherapy at different sites. These results have important implications for both melanoma evolution and target identification for immunotherapies, including ICB and cancer vaccines. This is the first study to trace subclonal evolution of neoantigens at single-cell resolution, demonstrating that Trisicell and our datasets represent important resources for the field.
2024-10-25 | GSE215960 | GEO
Project description:Aneuploidy results in decreased cellular fitness in many different species and model systems. However, aneuploidy is commonly found in cancer cells and often correlates with aggressive growth and poor prognosis, suggesting that the impact of aneuploidy on cellular fitness is context dependent. The BRG1 (SMARCA4) subunit of the SWI/SNF chromatin remodelling complex is a tumour suppressor that is frequently lost in cancer cells. Here, we used a chromosomally stable cell line to test the effect of BRG1 loss on the evolution of aneuploidy. We find that BRG1 deletion leads to an initial loss of fitness in this cell line that improves over time. The improved fitness correlates with a gain of extra copies of chromosome 18. Notably, changes in pathways that are known to promote tolerance to aneuploidy are evident immediately upon loss of BRG1, providing an environment where karyotype changes associated with a fitness advantage can be explored. At least in some genetic backgrounds, therefore, loss of the SWI/SNF complex can contribute to tumourigenesis through tolerance of aneuploidy.
2022-03-23 | PXD014954 | Pride
Project description:Whole Genome Sequencing of the murine breast cancer cell line 4T1 and of the murine melanoma cell line B16-ova was carried out with the aim of identifying somatic mutations. We also ran deep Mass Spectrometry proteomics analysis on the same cell lines, aiming to determine which somatic mutations carry over to the protein expression level. Further, we tested these cancer specific protein epitopes (putative neoantigens) for immunogenicity using mouse models. Finally, the putative neoantigens that showed good immunogenic potential were used in tumor growth control experiments with mice engrafted with the two tumor cell lines. In these experiments we tested whether cancer vaccines based on individual neoantigen peptides (MHC-I) restricted the growth of the tumor compared to adequate controls. The overall aim of the project is to validate the ability of our multi-omics/bioinformatics pipeline to identify and deliver neoantigens that can be used to suppress tumor growth. File names Sample names P10859_101_S1_L001_R1_001_BHKWV3CCXY 4T1_S1_L001_R1_001_BHKWV3CCXY P10859_101_S1_L001_R2_001_BHKWV3CCXY 4T1_S1_L001_R2_001_BHKWV3CCXY P10859_101_S1_L002_R1_001_BHKWV3CCXY 4T1_S1_L002_R1_001_BHKWV3CCXY P10859_101_S1_L002_R2_001_BHKWV3CCXY 4T1_S1_L002_R2_001_BHKWV3CCXY P10859_102_S2_L003_R1_001_BHKWV3CCXY B16-OVA_S2_L003_R1_001_BHKWV3CCXY P10859_102_S2_L003_R2_001_BHKWV3CCXY B16-OVA_S2_L003_R2_001_BHKWV3CCXY P10859_102_S2_L004_R1_001_BHKWV3CCXY B16-OVA_S2_L004_R1_001_BHKWV3CCXY P10859_102_S2_L004_R2_001_BHKWV3CCXY B16-OVA_S2_L004_R2_001_BHKWV3CCXY
2024-01-31 | E-MTAB-13635 | biostudies-arrayexpress
Project description:RNA Sequencing of the murine breast cancer cell line 4T1 and of the murine melanoma cell line B16-ova was carried out with the aim of establishing the complete transcriptome of these cell lines. Because these are cancer cells and we expect a lot of aberrant splicing, we carried out de novo assembly (genome guided) of the transcripts. We also ran deep Mass Spectrometry proteomics analysis on the same cell lines, aiming to determine which aberrant transcripts carry over to the protein expression level. Further, we tested these cancer specific protein epitopes (putative neoantigens) for immunogenicity using mouse models. Finally, the putative neoantigens that showed good immunogenic potential were used in tumor growth control experiments with mice engrafted with the two tumor cell lines. In these experiments we tested whether cancer vaccines based on individual neoantigen peptides (MHC-I) restricted the growth of the tumor compared to adequate controls. The overall aim of the project is to validate the ability of our multi-omics/bioinformatics pipeline to identify and deliver neoantigens that can be used to suppress tumor growth.
2024-06-30 | E-MTAB-14130 | biostudies-arrayexpress
Project description:We delineate subclonal expansion in a mouse melanoma models in response to immunotherapy, highlighting the role of neoantigens
2019-11-10 | GSE139248 | GEO
Project description:Effective anti-cancer immunity is associated with the presence of T cells directed at potentially immunogenic tumor neoantigens arising from tumor-specific mutation. We confirmed the expression of reported MC38 neoantigens (Nature 515: 572, 2014). MC38 cells in our laboratory had the same point mutation at amino acid position 299 in Adpgk (ASMTN[R/M]ELM), but did not have a point mutation at amino acid position 42 in Reps1 (AQL[P/A]NDVVL). The allele frequency of mutated Adpgk (ASMTNMELM) was 30%.
2019-02-13 | GSE126280 | GEO
Project description:Alteration of normal ploidy (aneuploidy) is an important mechanism of evolution of species. It has been linked to a rapid response to stress and is regarded as a hallmark of cancer. While increased genomic instability of aneuploid cells can accelerate genetic diversification and facilitate adaptation, these cells also face the adverse effects of gene imbalance, resulting in fitness cost. Here, to understand the mechanisms through which cells respond to aneuploidy and develop tolerance leading to fitness restoration, we subjected disomic (i.e. with an extra chromosome copy) strains of yeast to long-term experimental evolution, forcing disomy maintenance with selection markers. We characterized mutations, karyotype alterations and gene expression changes throughout adaptive evolution, and analyzed them to dissect the associated molecular strategies. Cells with different extra chromosomes accumulated mutations at distinct rates, and endured a diverse array of adaptive events. Despite remarkable diversity of these events, cells tended to evolve towards normal ploidy through both chromosomal DNA loss and changes in gene expression. We identified genes commonly altered during the evolution of disomic strains, and genes recurrently mutated in multiple lines. Our analyses revealed protein translation, amino acid biosynthesis, transcription regulation, stress response, and nucleotide and protein degradation as key pathways for the adaptive response to aneuploidy and identified transcription factors that mediate this response. Together, these findings define cellular strategies that underlie tolerance to aneuploidy.
2018-08-31 | GSE119272 | GEO
Project description:<p>The clinical picture of autonomic failure is dominated by disabling orthostatic hypotension. Recent developments in the understanding of the underlying pathophysiology of the discrete clinical forms of autonomic failure have revealed that participants with multiple system atrophy (MSA) are characterized by impairment of central autonomic pathways crucial for autonomic cardiovascular control, but have intact peripheral postganglionic noradrenergic fibers. Participants with MSA have peripheral residual sympathetic tone that is no longer modulated by central autonomic centers and is not under baroreflex control and, therefore, cannot be harnessed to improve their orthostatic hypotension. On the other hand, participants with pure autonomic failure (PAF) and with Parkinson' s disease (PD) are characterized by neurodegeneration and loss of peripheral noradrenergic fibers, as evidenced by low levels of plasma norepinephrine and absent cardiac uptake of labeled catechols. Pharmacological inhibition of the norepinephrine transporter (NET) is an example of an approach that can take advantage of the participants' own residual sympathetic tone. NET inhibition will increase synaptic norepinephrine that is tonically released in MSA participants by preventing its reuptake. This should result in an increase in blood pressure. </p> <p>This is a longitudinal study of 50 participants, age 18-80 years with neurogenic orthostatic hypotension associated with impaired reflexes. The purpose of this study is to determine if the magnitude of the pressor response to atomoxetine at study entry, will be useful as a biomarker to differentiate those participants that will ultimately be shown to have pre-ganglionic (central) lesions (MSA) with those shown to have post ganglionic (peripheral) lesions (PAF and PD). </p>
| phs001595 | dbGaP
Project description:Although closely related to plant evolution, polyploid sRNAs (small RNAs) were seldom studied with experiments, especially on genome-wide range. In this study, a rice twin-seeding (two seedlings from the same grain) line SARII-658 was employed to isolate autotriploids. Those autotriploids possess unique merits to study the two interesting topics: (i) natural polyploids; (ii) the autonomy of epigenetic variations (i.e. sRNAs) from genome doubling per se. sRNA libraries were prepared from those diploid-autotriploid twin-seedlings and then were sequenced to produce 13,308,226 short sequence reads in total. Out of the 35,429 miRNA genes and siRNA clusters, 1,547 (4.36%) changed their expression levels for two folds or above after genome doubling (thereinafter, referred those sRNAs as ploidy-sensitive). The expression-unregulated sRNAs (3.71%) were far more than the downregulated ones (0.64%), suggesting that the negative regulation of the coding gene by sRNA increase is more prevalent than the positive regulation during genome doubling. The expression of sRNAs were obviously increased and biased to accumulate toward centromeric and heterochromatic regions, suggesting that sRNAs should play a role in repressing transposition activity during genome doubling. Except transposition activity, the targets of those ploidy-sensitive sRNAs involved many kinds of gene function categories, suggesting an overall regulation of sRNAs to polyploid biological processes. Findings from this study will provide theoretical bases for elucidating epigenetic mechanism of plant and sRNA evolution via genome doubling. Examination of 2 different small RNA expression profilings in 2 ploidy plants.
2009-07-15 | E-GEOD-14462 | biostudies-arrayexpress
Project description:Melanomas accumulate a high burden of mutations that could potentially generate neoantigens, yet these tumors are still able to suppress the immune response in order to facilitate their continued growth. In this study, we identify subsets of human melanoma tumors that have partial loss of function mutations in ATR, a kinase that recognizes and repairs UV-induced DNA damage and is required for cellular proliferation. ATR mutant tumors exhibit both the accumulation of multiple mutations and the altered expression of inflammatory genes, resulting in decreased T-cell recruitment and increased recruitment of macrophages known to spur tumor invasion. Taken together, these studies identify a novel mechanism by which melanoma cells modulate the immune microenvironment to allow continued tumor growth.
2017-01-31 | GSE94264 | GEO