Project description:Fusion genes arising from cancer-associated somatic mutations are a potential rich source for highly immunogenic neo-antigens. However, their exploitation as targets for personalized cancer immunotherapy is currently limited by the lack of computational tools allowing transcriptome-wide identification of unique fusion genes in an accurate and sensitive manner. Here, we present EasyFuse, a computational pipeline, to detect individual and cancer-specific fusion genes in next-generation-sequencing transcriptome data obtained from human cancer samples. Using machine learning, EasyFuse predicts personal fusion genes with high precision and sensitivity and outperforms previously described approaches as qualified by an unprecedented ground-truth dataset of >1500 verification experiments in relevant patient samples. By testing immunogenicity with autologous blood lymphocytes from cancer patients we detected pre-established CD4+ and CD8+ T cell responses for 10 of 21 (48%), and for 1 of 30 (3%) of identified fusion genes, respectively. In conclusion, we demonstrate accurate detection of cancer-specific fusion genes. The high frequency of T cell responses detected in cancer patients support the relevance of private fusion genes as neo-antigens for personalized immunotherapies, especially for tumors with low point mutation burdens.
Project description:Disruption of splicing patterns due to mutations of genes coding splicing factors in tumors represents a potential source of tumor neo-antigens, which would be both public (shared between patients) and tumor-specific (not expressed in normal tissues). In this study, we show that mutations of the splicing factor SF3B1 in uveal melanoma (UM) generate such immunogenic neo-antigens. Memory CD8+ T cells specific for these neo-antigens are preferentially found in 20% of UM patients bearing SF3B1 mutated tumors. Single cell analyses of neo-epitope specific T cells from the blood identified large clonal T cell expansions, with distinct effector transcription patterns. Some of these expanded TCRs are also present in the corresponding tumors. CD8+ T cell clones specific for the neo-epitopes specifically recognize and kill SF3B1-mutated tumor cells, supporting the use of this new family of neo-antigens as therapeutic targets.
Project description:Purpose: In this study, we show that mutations of the splicing factor SF3B1 in uveal melanoma (UM) generate immunogenic neo-antigens.
Project description:Purpose: In this study, we show that mutations of the splicing factor SF3B1 in uveal melanoma (UM) generate immunogenic neo-antigens.
Project description:Purpose: In this study, we show that mutations of the splicing factor SF3B1 in uveal melanoma (UM) generate immunogenic neo-antigens.
Project description:Purpose: In this study, we show that mutations of the splicing factor SF3B1 in uveal melanoma (UM) generate immunogenic neo-antigens.
Project description:Detection of immunogenic proteins remains an important task for life sciences as it nourishes the understanding of pathogenicity, illuminates new potential vaccine candidates and broadens the spectrum of biomarkers applicable in diagnostic tools. Traditionally, immunoscreenings of expression libraries via polyclonal sera on nitrocellulose membranes or screenings of whole proteome lysates in 2-D gel electrophoresis are performed. However, these methods feature some rather inconvenient disadvantages. Screening of expression libraries to expose novel antigens from bacteria often lead to an abundance of false positive signals owing to the high cross reactivity of polyclonal antibodies towards the proteins of the expression host. A method is presented that overcomes many disadvantages of the old procedures. We incorporated a fusion tag prior to our genes of interest and attached the expressed fusion proteins covalently on microarrays. This enhances the specific binding of the proteins compared to nitrocellulose. Thus, it helps to reduce the number of false positives significantly. It enables us to screen for immunogenic proteins in a shorter time, with more samples and statistical reliability. We validated our method by employing several known genes from Campylobacter jejuni NCTC 11168. Four of proteins that have previously been described as immunogenic have successfully been assessed immunogenic abilities with our method. One protein with no known immunogenic behaviour before suggested potential immunogenicity. The method presented offers a new approach for screening of bacterial expression libraries to illuminate novel proteins with immunogenic features. It could provide a powerful and attractive alternative to existing methods and help to detect and identify bacterial virulence factors, vaccine candidates and potential biomarkers. The overall study was done with five technical replicates. Ten proteins derived from Campylobacter jejuni were tested regarding their immunogenic potential. The ten proteins derived from Campylobacter jejuni were fusion proteins, i.e., N-terminal HaloTag fused to: Gene <--> Protein cjaA <--> putative amino-acid transporter periplasmic solute-binding protein hisJ <--> histidine-binding protein precursor pal <--> peptidoglycan associated lipoprotein flaC <--> flagellin flaA <--> flagellin peb1a <--> bifunctional adhesin/ABC transporter aspartate/glutamate-binding protein pyrC <--> dihydroorotase (EC:3.5.2.3) pseB <--> UDP-GlcNAc-specific C4,6 dehydratase/C5 epimerase gapA <--> glyceraldehyde 3-phosphate dehydrogenase (EC:1.2.1.12) argC <--> N-acetyl-gamma-glutamyl-phosphate reductase (EC:1.2.1.38)
Project description:ost characterized tumor antigens are ‘genomic’, i.e. encoded by canonical, non-canonical or somatically mutated genomic sequences. We investigate here the presentation and immunogenicity of tumor antigens derived from non-canonical mRNA splicing events between coding exons and transposable elements (TEs). Comparing non-small cell lung cancer (NSCLC), an immunogenic tumor type, and diverse non-tumor tissues, we identify several thousand splicing junctions between exons and diverse TE classes. A subset of these junctions is both tumor-specific and shared across patients. HLA-I peptidomic identifies peptides encoded by tumor-specific junctions in primary NSCLC samples and lung tumor cell lines. Recurrent junction-encoded peptides are immunogenic in vitro and CD8+ T cells specific for junction-encoded epitopes are present in tumors and tumor-draining lymph nodes from NSCLC patients. We conclude that non-canonical splicing junctions between exons and TEs represent a source of recurrent, immunogenic tumor-specific antigens in NSCLC cancer patients.
Project description:Efforts to precisely identify tumor human leukocyte antigen presented peptides (HLAp) capable of mediating T cell based tumor rejection still face important challenges. Recent reports suggest that non-canonical cancer HLAp could be immunogenic but their identification requires highly sensitive and accurate mass-spectrometry (MS)-based proteogenomics approaches. Here, we present a novel MS-based analytical pipeline that can precisely characterize the non-canonical HLAp repertoire, incorporating whole exome sequencing, bulk and single cell transcriptomics, ribosome profiling, and a combination of two MS/MS search tools. This approach results in the accurate identification of hundreds of shared and tumor-specific non-canonical HLAp. Albeit often at low levels and in distinct subpopulations of cells, numerous non-canonical HLAp are shared across tumors. This analytical platform holds great promise for the discovery of novel cancer antigens for cancer immunotherapy.