Project description:Purpose: Tumor-specific antigens (TSAs) represent ideal targets for cancer immunotherapy, but very few of them have been identified. Therefore, the goal of this study was to develop a novel approach, combining RNA-Sequencing and mass spectrometry, to enlarge the landscape of actionable TSAs in seven human primary samples, namely 4 B-ALL and 3 lung tumor biopsies. Methods: We performed RNA-Sequencing on each primary tumor sample (unreplicated) with the Illumina HiSeq2000. Using those RNA-Sequencing data to build a global cancer database for each sample, we performed a transcriptomic-informed mass spectrometry analysis of their MHC I-associated peptides to identify TSAs. Results: We identified a total of 30 TSAs, 90% of which derived from allegedly non-coding regions and would have been missed by standard approaches. Moreover, most of these TSAs derived from non-mutated yet cancer-restricted transcripts that can be shared by multiple tumors. Conclusions: In conclusion, the strategy reported herein is readily applicable to human tumors and should considerably enlarge the landscape of actionable TSAs.
Project description:Purpose: Tumor-specific antigens (TSAs) represent ideal targets for cancer immunotherapy, but very few of them have been identified. Therefore, the goal of this study was to develop a novel approach, combining RNA-Sequencing and mass spectrometry, to enlarge the landscape of actionable TSAs in two murine cell lines, namely EL4 and CT26 cells. Methods: We performed RNA-Sequencing on both tumor cell lines (unreplicated) as well as on the syngeneic mature medullary thymic epithelial cells (mTEChi, in triplicate), using either the Illumina HiSeq200 or the Illumina NextSeq 500. Using those RNA-Sequencing data to build a global cancer database for each tumor cell line, we performed a transcriptomic-informed mass spectrometry analysis of their MHC I-associated peptides to identify TSAs. Results: We identified a total of 21 TSAs, 90% of which derived from allegedly non-coding regions and would have been missed by standard approaches. Moreover, about 70% of these TSAs derived from non-mutated yet cancer-restricted transcripts (e.g., endogenous retroelements) that can be shared by multiple tumors. Conclusions: In conclusion, the strategy reported herein is readily applicable to human tumors and should considerably enlarge the landscape of actionable TSAs.
Project description:Purpose: Tumor-specific antigens (TSAs) represent ideal targets for cancer immunotherapy, but very few of them have been identified. Therefore, the goal of this study was to develop a novel approach, combining RNA-Sequencing and mass spectrometry, to enlarge the landscape of actionable TSAs in seven human primary samples, namely 4 B-ALL and 3 lung tumor biopsies. Methods: We performed RNA-Sequencing on each primary tumor sample (unreplicated) with the Illumina HiSeq200. Using those RNA-Sequencing data to build a global cancer database for each sample, we performed a transcriptomic-informed mass spectrometry analysis of their MHC I-associated peptides to identify TSAs. Results: We identified a total of 30 TSAs, 90% of which derived from allegedly non-coding regions and would have been missed by standard approaches. Moreover, most of these TSAs derived from non-mutated yet cancer-restricted transcripts that can be shared by multiple tumors. Conclusions: In conclusion, the strategy reported herein is readily applicable to human tumors and should considerably enlarge the landscape of actionable TSAs.
Project description:Colorectal cancer is the second leading cause of cancer death worldwide, and the incidence of this disease is expected to increase as global socioeconomic changes occur. Immune checkpoint inhibition therapy is effective in treating a minority of colorectal cancer tumors; however, microsatellite stable tumors do not respond well to this treatment. Emerging cancer immunotherapeutic strategies aim to activate a cytotoxic T cell response against tumor-specific antigens, presented exclusively at the cell surface of cancer cells. These antigens are rare and are most effectively identified with a mass spectrometry-based approach, which allows the direct sampling and sequencing of these peptides. While the few tumor-specific antigens identified to date derived from coding regions of the genome, recent findings indicate that a large proportion of tumor-specific antigens originate from allegedly noncoding regions. Here, we employed a novel proteogenomic approach to identify tumor antigens in a collection of colorectal cancer-derived cell lines and biopsy samples consisting of matched tumor and normal adjacent tissue. The generation of personalized cancer databases paired with mass spectrometry analyses permitted the identification of more than 30 000 unique MHC I-associated peptides. We identified 19 putative tumor-specific antigens in both microsatellite stable and unstable tumors, over two-thirds of which were derived from non-coding regions. Many of these peptides were derived from source genes known to be involved in colorectal cancer progression, suggesting that antigens from these genes could have therapeutic potential in a wide range of tumors. These findings could benefit the development of T cell-based vaccines, in which T cells are primed against these antigens to target and eradicate tumors. Such a vaccine could be used in tandem with existing immune checkpoint inhibition therapies, to bridge the gap in treatment efficacy across subtypes of colorectal cancer with varying prognoses.
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.