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Breast cancer immunopeptidomes contain numerous shared tumor antigens.

ABSTRACT: Hormone receptor-positive breast cancer (HR+) is immunologically cold and has not benefited from advances in immunotherapy. In contrast, subsets of triple-negative breast cancer (TNBC) display high leukocytic infiltration and respond to checkpoint blockade. CD8+ T cells, the main effectors of anticancer responses, recognize MHC I-associated peptides (MAPs). Our work aimed to characterize the repertoire of MAPs presented by HR+ and TNBC tumors. Using mass spectrometry, we identified 57,094 unique MAPs in 26 primary breast cancer samples. MAP source genes highly overlapped between both subtypes. We identified 25 tumor-specific antigens (TSAs) mainly deriving from aberrantly expressed regions. TSAs were most frequently identified in TNBC samples and were more shared among The Cancer Genome Atlas (TCGA) database TNBC than HR+ samples. In the TNBC cohort, the predicted number of TSAs positively correlated with leukocytic infiltration and overall survival, supporting their immunogenicity in vivo. We detected 49 tumor-associated antigens (TAAs), some of which derived from cancer-associated fibroblasts. Functional expansion of specific T cell assays confirmed the in vitro immunogenicity of several TSAs and TAAs. Our study identified attractive targets for cancer immunotherapy in both breast cancer subtypes. The higher prevalence of TSAs in TNBC tumors provides a rationale for their responsiveness to checkpoint blockade.

SUBMITTER: Kina E

PROVIDER: S-EPMC10760959 | biostudies-literature | 2024 Jan

REPOSITORIES: biostudies-literature

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Breast cancer immunopeptidomes contain numerous shared tumor antigens.

Kina Eralda E Laverdure Jean-Philippe JP Durette Chantal C Lanoix Joël J Courcelles Mathieu M Zhao Qingchuan Q Apavaloaei Anca A Larouche Jean-David JD Hardy Marie-Pierre MP Vincent Krystel K Gendron Patrick P Hesnard Leslie L Thériault Catherine C Ruiz Cuevas Maria Virginia MV Ehx Grégory G Thibault Pierre P Perreault Claude C

The Journal of clinical investigation 20240102 1

Hormone receptor-positive breast cancer (HR+) is immunologically cold and has not benefited from advances in immunotherapy. In contrast, subsets of triple-negative breast cancer (TNBC) display high leukocytic infiltration and respond to checkpoint blockade. CD8+ T cells, the main effectors of anticancer responses, recognize MHC I-associated peptides (MAPs). Our work aimed to characterize the repertoire of MAPs presented by HR+ and TNBC tumors. Using mass spectrometry, we identified 57,094 unique ...[more]

PMID: 37906288

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Project description:Copy number variant (CNV) analysis was performed on renal cell carcinoma (RCC) specimens (chromophobe, clear cell, oncocytoma, papillary type 1, papillary type 2) using high resolution arrays (1.85 million probes). RCC samples exhibited diverse genomic changes within and across tumor types ranging from 106 CNV segments in a clear cell specimen to 2238 CNV segments in a papillary type 2 specimen. Despite the genomic heterogeneity, distinct CNV segments were common within each of 4 tumor classifications: chromophobe (7 segments), clear cell (3 segments), oncocytoma (9 segments), and papillary type 2 (2 segments). Shared segments ranged from a 6.1 Kb deletion among oncocytomas to a 208.3 Kb deletion common to chromophobes. Among common tumor type-specific variations, chromophobe, clear cell and oncocytomas comprised exclusively non-coding DNA. No CNV regions were common to papillary type 1 specimens although there were 12 amplifications and 12 deletions in 5 of 6 samples. Three microRNAs and 12 mRNA genes had M-bM-^IM-% 98% of their coding region contained within CNV regions including multiple gene families (chromophobe: amylase 1A, 1B, 1C; oncocytoma: general transcription factor 2H2, 2B, 2C, 2D). Gene deletions involved in histone modification and chromatin remodeling affected individual subtypes (clear cell: SFMBT, SETD2; papillary type 2: BAZ1A) as well as the collective RCC group (KDM4C). The genomic amplifications/deletions identified in each renal tumor type represent potential diagnostic and/or prognostic biomarkers. Tissue samples were obtained from the University of Pittsburgh Health Sciences Tissue Bank (HSTB) using an honest broker system and according to IRB approved protocol #970480. Samples were acquired as surgical specimens, flash-frozen in a 1.8 ml cryotube (NalgeNunc, Inc., Rochester, NY) followed by immediate storage at -80C. Each tumor sample (n=27) was classified into one of 5 renal cancer subtypes (chromophobe: n=5, clear cell: n=5, oncocytoma: n=5, papillary type 1: n=6, papillary type 2: n=6) by consensus evaluation of correlative hematoxylin and eosin stained slides performed independently by 3 anatomical pathologists. The three pathologists also confirmed the absence of pathological features in adjacent normal renal samples (n=9) and this normal reference group was expanded by inclusion of 14 normal thyroid samples and 8 normal lung specimens. DNA from each of these specimens was analyzed using genotyping microarrays (SNP 6.0, Affymetrix, Sunnyvale, CA).

Project description:BackgroundCertain phosphorylated peptides are differentially presented by major histocompatibility complex (MHC) molecules on cancer cells characterized by aberrant phosphorylation. Phosphopeptides presented in complex with the human leukocyte antigen HLA-A*02:01 provide a stability advantage over their non-phosphorylated counterparts. This stability is thought to contribute to enhanced immunogenicity. Whether tumor-associated phosphopeptides presented by other common alleles exhibit immunogenicity and structural characteristics similar to those presented by A*02:01 is unclear. Therefore, we determined the identity, structural features, and immunogenicity of phosphopeptides presented by the prevalent alleles HLA-A*03:01, HLA-A*11:01, HLA-C*07:01, and HLA-C*07:02.MethodsWe isolated peptide-MHC complexes by immunoprecipitation from 11 healthy and neoplastic tissue samples using mass spectrometry, and then combined the resulting data with public immunopeptidomics data sets to assemble a curated set of phosphopeptides presented by 96 samples spanning 20 distinct healthy and neoplastic tissue types. We determined the biochemical features of selected phosphopeptides by in vitro binding assays and in silico docking, and their immunogenicity by analyzing healthy donor T cells for phosphopeptide-specific multimer binding and cytokine production.ResultsWe identified a subset of phosphopeptides presented by HLA-A*03:01, A*11:01, C*07:01 and C*07:02 on multiple tumor types, particularly lymphomas and leukemias, but not healthy tissues. These phosphopeptides are products of genes essential to lymphoma and leukemia survival. The presented phosphopeptides generally exhibited similar or worse binding to A*03:01 than their non-phosphorylated counterparts. HLA-C*07:01 generally presented phosphopeptides but not their unmodified counterparts. Phosphopeptide binding to HLA-C*07:01 was dependent on B-pocket interactions that were absent in HLA-C*07:02. While HLA-A*02:01 and HLA-A*11:01 phosphopeptide-specific T cells could be readily detected in an autologous setting even when the non-phosphorylated peptide was co-presented, HLA-A*03:01 or HLA-C*07:01 phosphopeptides were repeatedly non-immunogenic, requiring use of allogeneic T cells to induce phosphopeptide-specific T cells.ConclusionsPhosphopeptides presented by multiple alleles that are differentially expressed on tumors constitute tumor-specific antigens that could be targeted for cancer immunotherapy, but the immunogenicity of such phosphopeptides is not a general feature. In particular, phosphopeptides presented by HLA-A*02:01 and A*11:01 exhibit consistent immunogenicity, while phosphopeptides presented by HLA-A*03:01 and C*07:01, although appropriately presented, are not immunogenic. Thus, to address an expanded patient population, phosphopeptide-targeted immunotherapies should be wary of allele-specific differences.

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Breast cancer immunopeptidomes contain numerous shared tumor antigens.

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Breast cancer immunopeptidomes contain numerous shared tumor antigens.

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