Project description:Systemic pan-tumor analyses may reveal the significance of common features implicated in cancer immunogenicity and patient survival. Here, we provide a comprehensive multi-omics data set for 32 patients across 25 tumor types for proteogenomic-based discovery of neoantigens. By using an optimized computational approach, we discover a large number of tumor-specific and tumor-associated antigens. To create a pipeline for the identification of neoantigens in our cohort, we combine DNA and RNA sequencing with MS-based immunopeptidomics of tumor specimens, followed by the assessment of their immunogenicity and an in-depth validation process. We detect a broad variety of non-canonical HLA-binding peptides in the majority of patients demonstrating partially immunogenicity. Our validation process allows for the selection of 32 potential neoantigen candidates. The majority of neoantigen candidates originates from variants identified in the RNA data set, illustrating the relevance of RNA as a still understudied source of cancer antigens. This study underlines the importance of RNA-centered variant detection for the identification of shared biomarkers and potentially relevant neoantigen candidates.
Project description:Neoantigen discovery in pediatric brain tumors is hampered by their low mutational burden and scant tissue availability. We developed a low-input proteogenomic approach combining tumor DNA/RNA sequencing and mass spectrometry proteomics to identify tumor-restricted (neoantigen) peptides arising from multiple genomic aberrations to generate a highly target-specific, autologous, personalized T cell immunotherapy. Our data indicate that novel splice junctions are the primary source of neoantigens in medulloblastoma, a common pediatric brain tumor. Proteogenomically identified tumor-specific peptides are immunogenic and generate MHC II-based T cell responses. Moreover, polyclonal and polyfunctional T cells specific for tumor-specific peptides effectively eliminated tumor cells in vitro. Targeting novel tumor-specific antigens obviates the issue of central immune tolerance while potentially providing a safety margin favoring combination with other immune-activating therapies. These findings demonstrate the proteogenomic discovery of immunogenic tumor-specific peptides and lay the groundwork for personalized targeted T cell therapies for children with brain tumors.
Project description:MC38 colorectal tumor cell lines from two different sources display substantial differences in transcriptome, mutanome and neoantigen expression
Project description:Cell therapy with tumor-infiltrating lymphocytes (TIL) has yielded durable responses for multiple cancer types, but the causes of therapeutic resistance remain largely unknown. Here multi-dimensional analysis was performed on time serial tumor and blood in a lung cancer TIL therapy trial. Using T-cell receptor sequencing on both functionally expanded T cells and neoantigen-loaded tetramer-sorted T cells, we identified neoantigen specific TCRs. We then mapped clones into individual transcriptomes and found that neoantigen-reactive clonotypes expressed a dysfunctional program and lacked stem-like features among patients who lacked clinical benefit. Tracking neoantigen-reactive clonotypes over time, decay of antigen-reactive peripheral T-cell clonotypes was associated with the emergence of progressive disease. Further, subclonal neoantigens previously targeted by infused T cells were subsequently absent within tumors at progression, suggesting potential adaptive resistance. Our findings suggest that targeting clonal antigens and circumventing dysfunctional states may be important for conferring clinical responses to TIL therapy.
Project description:It has been hypothesized that neoantigen-specific T cells play a major role in effective cancer immunotherapy, including neoantigen vaccines, immune checkpoint blockade (ICB) therapy, and adoptive T cell therapy using tumor-infiltrating lymphocytes (TILs). The major source of neoantigens are mutated proteins derived from non-synonymous mutations found in tumor genomic DNA. It’s highly conceivable that non-synonymous mutations found in tumor mitochondrial DNA (mtDNA) can also generate neoantigens that can be recognized by T-cell receptors (TCRs). This project contains two types of single-cell data. One is single-cell CITEseq (5' mRNA plus antibody feature barcode plus TCR) seqeuncing to identify antigen-specific TCRs. The other is single-cell ATAC-seq to detect chromatin accessiblities and mtDNA.
Project description:Background. Dendritic cell (DC)-based neoantigen vaccination holds potential as a safe and effective adjuvant therapy for patients with early-stage, resectable NSCLC, a tumor type typically characterized by high mutational loads. DCs have the unique ability to elicit robust antitumoral T-cell responses, while neoantigens are ideal targets to elicit high-affinity T cell responses with exquisite tumor specificity. Here, we present the results of a phase I clinical trial in which a novel DC vaccine targeting neoantigens was evaluated in six patients with early stage, resected NSCLC. Methods. Tumor samples were subjected to a comprehensive neoantigen identification approach encompassing genomics, transcriptomics and immunopeptidomics. Patients underwent leukapheresis for the manufacturing of monocyte-derived DCs loaded with neoantigens (Neo-mDCs) according to a four-day protocol. Neo-mDCs were injected intravenously following an intrapatient dose escalation scheme. Primary endpoint of the trial was safety. Secondary endpoints were feasibility, immunogenicity, and relapse-free survival. As a quality control, dendritic cells transfected with the mRNA-encoded neoantigen were analyzed by shotgun proteomics to validate expression of the mRNA-encoded neoantigen. Results. The vaccine was demonstrated to be feasible and safe. T cell responses were observed in 5 of 6 vaccinated patients and were dominated by CD8+ T cells, which could be detected ex vivo at high frequencies >1.5 years after the last dose. Furthermore, single cell analysis indicated that the CD8+ T cell responsive population was polyclonal and exhibited the near entire spectrum of T cell differentiation states, including a naïve-like state associated with long lasting memory. Additionally, mRNA-encoded neoantigen were detected by shotgun proteomics in four patients out of the six patients that were tested.
2024-03-17 | PXD044799 | Pride
Project description:Opportunity of NGS-STR for tumor source identification