Project description:Treatment of late-stage melanoma patients with immune checkpoint blockade (ICB) is currently one of the most effective standard therapies. The response rates upon neoadjuvant ICB in stage III melanoma are higher as compared to stage IV disease. Given that successful ICB depends on systemic immune response, we hypothesized that systemic immune suppression might be a mechanism responsible for lower response rates in late-stage disease, and also potentially with disease recurrence in early-stage disease.
Project description:The inability of lymphocytes to infiltrate the tumor nest drastically limits immune checkpoint blockade (ICB) responsiveness. Analyzing the immune landscape of matched pre- and early on-treatment biopsies of melanoma patients undergoing ICB therapy, we observed a significant increase in cytotoxic NK cells in early on-treatment biopsies from non-responders. Spatial OMICs revealed that while NK cells colocalized with CD8 T cells within the tumor bed in responding lesions, they were excluded from the tumor parenchyma in non-responding lesions. Strikingly, depletion of NK cells using a NK1.1 antibody or the FDA-approved drug Daratumumab in a unique melanoma mouse model exhibiting an immune-excluded phenotype unleashed immune infiltration of the tumor core and tumor clearance upon ICB exposure. Mechanistically, we show that NK cells are actively recruited to immune-excluded areas upon ICB exposure via the chemokine receptor CX3CR1 to suppress tumor infiltration and antitumor function of CD8 T cells, possibly by promoting ferroptosis.
Project description:Immune checkpoint blockade (ICB) is the current first-line treatment for metastatic melanoma. However, ICB fails in many patients and has dangerous side effects. Rigosertib (RGS), a non-ATP-competitive small molecule RAS mimetic, has the potential to block oncogenic RAS-RAF-MEK-ERK and/or PI3K-AKT-mTOR signaling pathways. RGS treatment (300mg/kg) of melanoma tumor-bearing mice is well tolerated and results in ~50% inhibition of tumor growth as monotherapy and ~70% inhibition in combination with ICB. RGS-induced tumor inhibition depends on the induction of CD40 expression on melanoma cells, followed by immunogenic cell death, leading to an inflamed tumor microenvironment with enrichment of dendritic cells and activated CD8+ T cells. Highlights • RGS impairs melanoma tumor growth via direct killing and immunogenic cell death that promotes an inflamed tumor microenvironment. • RGS-induced tumor inhibition depends on the induction of CD40 expression on melanoma cells. • Combining RGS with αPD1+αCTLA4 improves tumor response. • Tumor CD40 levels are prognostic for therapeutic response to RGS and BRAF inhibitor. Significance: A high CD40 expression level correlates with CD80, ICOS-L, beneficial type I T cell responses, and better survival in melanoma patients (cBioPortal database). Tumor CD40 levels are prognostic for therapeutic response to RGS and BRAF inhibitor (DepMap and Oncomine databases), and RGS induces CD40 expression in melanoma tumor cells. Our preclinical data support the therapeutic use of RGS plus αPD1+αCTLA4 in RAS/RAF/MEK and/or PI3K pathway-activated melanoma tumors and point to the need for clinical trials to determine the clinical benefit of RGS plus ICB for metastatic melanoma patients who do not respond to ICB alone.
2021-06-15 | GSE149737 | GEO
Project description:Shotgun Metagenomics data for NCGS and IBS patients
Project description:In this comprehensive study, the authors have developed concise models integrating clinical, genomic and transcriptomic features to predict intrinsic resistance to anti-PD1 Immune Checkpoint Blockade (ICB) treatment in individual tumors. It's important to note that their validation was performed in smaller, independent cohorts, constrained by data availability. The authors have developed two Logistic Regression based models for Ipilimumab treated and Ipilimumab naive patients with metastatic melanoma. The main predictive features for the Ipilimumab treated patients are MHC-II HLA, LDH at treatment initiation and the presence of lymph node metastases (LN met), chosen using forward selection methodology. The main predictive features for the Ipilimumab naive patients are tumor heterogeneity, tumor ploidy and tumor purity, chosen using forward selection methodology.
Please note that in these models, the output ‘1’ means progressive disease (PD) and ‘0’ means non-PD. The original GitHub repository can be accessed at https://github.com/vanallenlab/schadendorf-pd1
Project description:Non-inflamed (cold) tumors such as leiomyosarcoma (LMS) do not benefit from immune checkpoint blockade (ICB) monotherapy. Combining ICB with angiogenesis-, or poly-ADP ribose polymerase (PARP) inhibitors may increase tumor immunogenicity by altering the immune cell composition of the tumor microenvironment (TME). The DAPPER phase II study evaluated the safety, immunologic, and clinical activity of ICB-based combinations in pre-treated LMS patients.
Project description:Unleashing the immune anti-tumor response through immune checkpoint blockade (ICB) has been successful in treating many solid-tumor malignancies, including metastatic melanoma. When successful, the ICB response can be potent; however, half of patients fail to respond. ICB responsiveness is impacted by the harsh solid tumor microenvironment (TME), which is characterized by metabolic stress. The TME impacts tumor antigenicity, with ICB-responsive melanomas exhibiting increased major histocompatibility complex class I (MHC-I) expression. Further investigation of tumor immunogenicity in the context of the TME may improve cellular therapies. Here, we define and characterize an epigenetic mechanism regulating melanoma antigen presentation driven by prolonged metabolic stress. Murine and human melanoma cell lines were cultured under prolonged metabolic stress, forcing cells to adapt to the absence of glucose. Melanoma cells adapted to the absence of glucose have IFN-gamma-independent increases in MHC-I and an increased sensitivity to T cell-mediated killing. Proteomic analysis revealed dysregulation of histone epigenetic modifiers under prolonged metabolic stress, specifically loss of histone methyltransferase EZH2 (Enhancer of Zeste Homolog 2). EZH2 directly silences gene transcription via catalyzing H3K27me3. Following metabolic adaptation, ChIP-sequencing and ChIP-PCR revealed H3K27me3 loss at genes specific to MHC-I antigen presentation. Prolonged metabolic stress in melanoma cells blunt EZH2 levels and H3K27me3 levels at promoters of genes regulating MHC-I presentation, resulting in elevated MHC-I antigenicity and increased CD8+ T cell killing. This demonstrates potential for EZH2 abundance and mutational status as a prognostic indicators of ICB-responsiveness in metastatic melanoma and supports EZH2 inhibition as adjuvant for immunotherapies
Project description:Immune checkpoint blockade (ICB) has demonstrated efficacy in patients with melanoma, but many exhibit poor responses. Using single cell RNA sequencing of melanoma patient-derived circulating tumor cells (CTCs) and functional characterization using mouse melanoma models, we show that the KEAP1/NRF2 pathway modulates sensitivity to ICB, independently of tumorigenesis. The NRF2 negative regulator, KEAP1, shows intrinsic variation in expression, leading to tumor heterogeneity and subclonal resistance.
Project description:Immune checkpoint blockade (ICB) has demonstrated efficacy in patients with melanoma, but many exhibit poor responses. Using single cell RNA sequencing of melanoma patient-derived circulating tumor cells (CTCs) and functional characterization using mouse melanoma models, we show that the KEAP1/NRF2 pathway modulates sensitivity to ICB, independently of tumorigenesis. The NRF2 negative regulator, KEAP1, shows intrinsic variation in expression, leading to tumor heterogeneity and subclonal resistance.
Project description:Intratumoral heterogeneity (ITH) arises from distinct subclonal expansion following genetic or epigenetic alterations, and profoundly influences how tumors response to their immune microenvironment. Tumor progression trees based on single-cell mutational profiles have made it possible to trace subclonal evolution; however, conventional tree-building methods can incorporate only a limited number of cells and mutations, restricting their application to larger single-cell data. To investigate the effect of ITH on the therapeutic response of melanoma, we have developed Trisicell (https://trisicell.rtfd.io), a computational toolkit for scalable inference of mutational ITH through assessment of single-cell genomic variant data. By applying Trisicell to genetically matched mouse melanoma datasets, we found that expressed mutations are sufficient to effectively drive subclonal evolution. On single-cell, full-length RNA sequencing data of mouse melanoma from preclinical immune checkpoint blockade (ICB) studies, the analysis showed that the subtree-seeding mutations in the trees identified distinct subclones associated with a specific developmental state and neural crest lineage markers. Using the tree to trace cell lineages, we found that neoantigens depleted by ICB were predominantly expressed in minor subclones, suggesting that post-treatment recurrence is driven by immunoediting. Moreover, these neoantigens were enriched with those derived from frameshift mutations and mutated nuclear genes. Importantly, recurrently mutated genes in ICB-responding human melanoma exhibited the same features. We next used Trisicell to analyze single-cell, full-length RNA data of brain metastases (BM) from melanoma patients treated with ICB, and discovered that relapsing BM from ICB-responding patients exhibited subclones that also expressed a higher fraction of frameshift mutations and were associated with elevated levels of infiltrated T cells. Notably, they also exhibited more mutated HLA genes and expressed high level of the novel immune checkpoint HLA-G, a putative local immunosuppressive mechanism. In summary, applying Trisicell to single-cell transcriptomic analyses allowed us to identify novel features of ICB-responding melanoma neoantigens and distinct mechanisms for adapting to immunotherapy at different sites. These results have important implications for both melanoma evolution and target identification for immunotherapies, including ICB and cancer vaccines. This is the first study to trace subclonal evolution of neoantigens at single-cell resolution, demonstrating that Trisicell and our datasets represent important resources for the field.