Project description:Immune checkpoint inhibitors (CPIs) have revolutionised cancer treatment, with previously untreatable disease now amenable to potential cure. Combination regimens of anti-CTLA-4 and anti-PD-1 show enhanced efficacy but are prone to off-target immune-mediated tissue injury, particularly at the barrier surfaces. CPI-induced colitis is a common and serious complication. A higher proportion of patients undergoing monotherapy anti-CTLA-4 treatment tend to develop colitis compared to monotherapy treated anti-PD-1 treated patients. This effect is enhanced when patients are treated with both drugs. To probe the impact of either anti-CTLA4 or anti-PD1 on intestinal homeostasis, mice were challenged with anti-CTLA-4 and anti-PD-1 immunotherapy in either monotherapy or together in combination. Manipulation of the intestinal microbiota has also been shown to be important in both this model, from previous data, and in patients. Colonic immune responses were then profiled using bulk RNA-sequencing.
Project description:Human fecal 16S rRNA gene sequencing data from patients treated with combined anti-CTLA-4 and anti-PD-1 immunotherapy for advanced melanoma.
Project description:This study concurrently examined the genome, transcriptome, methylome and immune cell infiltrates in baseline tumors from advanced cutaneous melanoma patients treated with anti-PD-1 +/- anti-CTLA-4 immune checkpoint immunotherapy. Illumina MethylationEPIC BeadChip array analysis of 43 melanoma tumors was carried out as part of the study. Higher PSMB8 methylation (and therefore lower PSMB8 expression) was associated with poor response to immunotherapy. There were higher amounts of CD8+ T cells, as estimated by methylCIBERSORT, in the tumor microenvironment of good responders. Although we observed a significant correlation between PD-L1 expression and methylation of the cg197224470 CpG site, there was no significant difference between PD-L1 methylation in good and poor responders.
Project description:<p>Blockade of T cell coinhibitory molecules such as CTLA-4 and PD-1, can activate T cell antitumor response. Although these immune checkpoint blockades (CTLA-4 blockade and PD-1 blockade) have shown durable response, response rate is modest. Therefore, there is a need to find stable biomarkers predictive of response to immune checkpoint blockades and to understand underlying resistance mechanisms. We collected longitudinal tumor biopsies from a cohort of metastatic melanoma patients treated with sequential immune checkpoint blockades and performed whole exome sequencing of this cohort. The comprehensive genomic characterization of tumors enabled identification of higher copy number loss burden as a resistance mechanism and clonal T cell repertoire as a predictive biomarker.</p>
Project description:Personalized peptide vaccination (PPV) is one of the attractive immunotherapy with high immune-boosting effects. However, as with most therapeutic agents, PPV does not elicit beneficial immune and/or clinical responses in all of the treated cancer patients. To identify prognostic biomarker for the selection of patients most likely to benefit from PPV, we conducted whole genome gene expression analysis of prevaccination peripheral blood mononuclear cells (PBMCs) of 112 castration-resistant prostate cancer (CRPC) patients.
Project description:<p>Immune checkpoint inhibitors are effective cancer treatments, but molecular determinants of clinical benefit are unknown. Ipilimumab and tremelimumab are antibodies against cytotoxic T-lymphocyte antigen 4 (CTLA-4). Anti-CTLA-4 treatment prolongs overall survival in patients with melanoma. CTLA-4 blockade activates T cells and enables them to destroy tumor cells.</p> <p>We obtained tumor tissue from patients with melanoma who were treated with ipilimumab or tremelimumab. Whole-exome sequencing was performed on tumors and matched blood samples. Somatic mutations and candidate neoantigens generated from these mutations were characterized. Neoantigen peptides were tested for the ability to activate lymphocytes from ipilimumab-treated patients.</p> <p>Malignant melanoma exomes from 64 patients treated with CTLA-4 blockade were characterized with the use of massively parallel sequencing. A discovery set consisted of 11 patients who derived a long-term clinical benefit and 14 patients who derived a minimal benefit or no benefit. Mutational load was associated with the degree of clinical benefit (P = 0.01) but alone was not sufficient to predict benefit. Using genomewide somatic neoepitope analysis and patient-specific HLA typing, we identified candidate tumor neoantigens for each patient. We elucidated a neo-antigen landscape that is specifically present in tumors with a strong response to CTLA-4 blockade. We validated this signature in a second set of 39 patients with melanoma who were treated with anti-CTLA-4 antibodies. Predicted neoantigens activated T cells from the patients treated with ipilimumab.</p>
Project description:The ability to modulate immune-inhibitory pathways using checkpoint blockade antibodies such as PD-1, PD-L1, and CTLA-4 represents a significant breakthrough in cancer therapy in recent years. This has driven interest in identifying small-molecule-immunotherapy combinations to increase the proportion of responses. Murine syngeneic models, which have a functional immune system, represent an essential tool for pre-clinical evaluation of new immunotherapies. However, immune response varies widely between models and the translational relevance of each model is not fully understood, making selection of an appropriate pre-clinical model for drug target validation challenging. Utilizing RNAseq transcriptomic profiling, we have characterised the changes in gene regulatory pathways and immune populations in CT26 mice after treatment with the combination of anti-PD-L1 and anti-CTLA-4 antibodies. At day 7 post tumor implant, the pathways analysis of differentially expressed genes indicated an enrichment for migration of leukocytes in response to inflammation and communication between innate and adaptive immune cells. Similarly, analysis of upstream regulators suggested that lipopolysaccharide, IL-1B, TNF, IFNG, and NFKB1A pathways associated with inflammation were activated. At day 14, pathways related T-helper cell signalling pathways were upregulated. In addition, upstream regulators of the lipopolysaccharide and IFNG pathway, as well STAT1 and IL21 pathway were enriched, indicative of innate and adaptive immune response to inflammation.
Project description:<p>Immune checkpoint therapies, including monoclonal antibodies to programmed cell death-1 (PD-1) and cytotoxic % lymphocyte associated protein-4 (CTLA-4), yield durable clinical responses across many tumor types, including metastatic melanoma, non-small cell lung cancer (NSCLC), and renal cell carcinoma (RCC). However, predictors of response to these therapies in RCC are still unknown. Genomic characterization of large clinical cohorts of patients treated with anti-CTLA-4 and anti-PD-1 agents in melanoma and NSCLC have suggested that high mutational burden, high neoantigen burden, and high expression of certain genes in pre-treatment tumors may be associated with patient response to these therapies. In this study, we sought to investigate genomic predictors of response to anti-PD1 therapy in metastatic RCC in two independent clinical cohorts using whole exome and whole transcriptome sequencing.</p>