Dataset Information

Immunopeptidomics guided identification of neoantigens in non-small cell lung cancer

ABSTRACT: Discovery of tumour specific peptides (neoantigens) generating target specific personalised T cell therapies is difficult because of the complex relationship between genetic mutations and neoantigen presentation. Studies predicting neoantigens have a 5% success rate, and direct observations of neoantigens are even rarer. We have developed a mass spectrometry proteomics guided approach to identify neoantigens in non-small cell lung cancer (NSCLC). We hypothesised that by characterising the observable peptides presented by HLA molecules (the immunopeptidome) we might better predict which mutations lead to neoantigens. From a cohort of 24 NSCLC patients, we performed a detailed analysis of 3 adenocarcinoma and 3 squamous cell carcinoma samples. Our workflow identified neoantigens generating functional T cell responses in 5 out of 6 patients, with one directly observed neoantigen, and an overall response rate of 20% of predicted neoantigens.

INSTRUMENT(S):

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Lung

DISEASE(S): Lung Cancer

SUBMITTER: Alistair Bailey

LAB HEAD: Paul J Skipp

PROVIDER: PXD028990 | Pride | 2026-07-03

REPOSITORIES: Pride

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Dataset's files

Source:

			Action	DRS
	A133_TL1202_TP00_T-DNA-mutanome-2020-12-16.fasta	Fasta
	A134_TL1230_TP00_T-DNA-mutanome-2020-12-16.fasta	Fasta
	A136_TL1269_TP00_T-DNA-mutanome-2020-12-16.fasta	Fasta
	A137_TL1272_TP00_T-DNA-mutanome-2020-12-16.fasta	Fasta
	A139_TL1299_TP00_T-DNA-mutanome-2020-12-16.fasta	Fasta

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Immunopeptidomics-guided identification of functional neoantigens in non-small cell lung cancer.

Nicholas Ben B Bailey Alistair A McCann Katy J KJ Wood Oliver O Currall Eve E Johnson Peter P Elliott Tim T Ottensmeier Christian C Skipp Paul P

NPJ precision oncology 20260610

Non-small cell lung cancer (NSCLC) has poor survival even with modern checkpoint inhibitor therapies. Personalised vaccines based on short peptide neoantigens containing tumour mutations are an attractive precision medicine strategy, but identifying therapeutically relevant neoantigens remains challenging, with existing methods yielding positive responses in only 6% of candidates tested. We developed an immunopeptidomics approach to improve neoantigen identification in 24 NSCLC patients (15 aden ...[more]

PMID: 42270771

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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. Using genomics and transcriptopmics data, tumor-specific antigens were identified by a bioinformatics approach. Additionally, immunopeptidomics was performed by immunoprecipitation of human MHC class I molecule followed by immunopeptides enrichment and LC-MS/MS analysis. Two immunopeptidomics screens were performed. In the first immunopeptidomics screen, patient-derived tumors were analyzed to uncover neoepitopes specific for the patient. In the second, screen, patient-derived EBV-immortilized B cell lines overexpressing the selected neoepitopes were analyzed to verify that the predicted neoepitopes can bind to the HLA haplotypes of the patients. For anti-tumor vaccination, 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. Results. In the first immunopeptidomics screen, one neoepitopes derived was identified from the tumor of one patient. In the second immunopeptidomics screen, several predicted neoepitopes were confirmed to be presented on the HLA haplotypes of the patients by analyzing the patient-derived EBV-immortilized B cell lines. Additionally, 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 but excluding exhausted cell states. Three of six vaccinated patients experienced disease relapse. Conclusion. Neo-mDC vaccination is safe and feasible. Vaccination induces large populations of neoantigen-specific T-cell responses containing long lasting memory and effector cells in early-stage NSCLC patients, suggesting clinical potential.

Project description:Background: Patient derived organoids (PDOs) can be established from colorectal cancers as in vitro models to interrogate cancer biology and its clinical relevance. We applied mass spectrometry (MS) immunopeptidomics to investigate neoantigen presentation and whether this can be augmented through interferon gamma (IFN) or MEK-inhibitors. Methods: Four PDOs from chemotherapy refractory and one from a treatment naïve CRC were expanded to replicates with 100 million cells each, and HLA class I and class II peptide ligands were analysed by MS. Results: We identified an average of 9,936 unique peptides per PDO which compares favourably against published immunopeptidomics studies, suggesting high sensitivity. Loss of heterozygosity of the HLA locus was associated with low peptide diversity in one PDO. Peptides from genes without detectable expression by RNA-sequencing were rarely identified by MS. Only 3 out of 612 non-silent mutations encoded for neoantigens that were detected by MS. Treatment of four PDOs with IFN upregulated HLA class I expression and qualitatively changed the immunopeptidome, with increased presentation of IFN-inducible genes. HLA class II presented peptides increased on average 16-fold with IFN treatment. MEK-inhibitor treatment showed no consistent effect on class I or II HLA expression or the peptidome. Importantly, no additional HLA class I or II presented neoantigens became detectable with any treatment. Conclusions: Only 3 out of 612 non-synonymous mutations encoded for neoantigens that were detectable by MS. Although MS has sensitivity limits and biases, and likely underestimated the true neoantigen burden, this established a lower bound of the percentage of non-silent mutations that encode for presented neoantigens, which may be as low as 0.5%. This could be a reason for the poor responses of non-hypermutated CRCs to immune checkpoint inhibitors. MEK-inhibitors recently failed to improve checkpoint-inhibitor efficacy in CRC and the observed lack of HLA upregulation or improved peptide presentation may explain this.

Project description:All nucleated mammalian cells express major histocompatibility complex (MHC) proteins that present peptides on cell surfaces for immune surveillance. These MHC-presented peptides (pMHC) can convey non-self antigens derived from pathogens or mutations to amount T-cell responses. Alterations in tumor-specific antigens – particularly mutation-bearing peptides (neoantigens) presented by MHC — can serve as potent substrates for anti-tumor immune responses. Here we employed an integrated genomic and proteomic antigen discovery strategy aimed at measuring interferon gamma (IFN-γ) induced alterations to antigen presentation, using a lymphoma cell line. IFN-γ treatment resulted in a set of differentially expressed proteins (2 % of all quantified proteins) including components of antigen presentation machinery or interferon signaling pathways. In addition, several proteasome subunits were found to be modulated, consistent with previous reports of immunoproteasome induction by IFN-γ exposure. This finding suggests that a modest proteomic response to IFN-γ could create larger alteration to cells antigen repertoires. Accordingly, by surveying immunopeptides, distinct peptide repertoires were exclusively observed in the IFN-γ induced samples. Furthermore, an additional set of presented peptides distinguished control and the IFN-γ samples by their altered relative abundances including neoantigens. Accordingly, we developed a classification system to distinguish peptides which are differentially presented due to altered expression from novel peptides resulting from changes in antigen processing. Taken together, these data demonstrate that IFN-γ can re-shape antigen repertoires by identity and by abundance. Extending this approach to models with greater clinical relevance should help develop strategies by which immunopeptide repertoires are intentionally reshaped to improve endogenous or vaccine-induced anti-tumor immune responses and potentially anti-viral immune responses.