Editing the immunopeptidome of melanoma cells using a potent inhibitor of endoplasmic reticulum aminopeptidase 1 (ERAP1)

AbstractThe efficacy of cancer immunotherapy, including treatment with immune-checkpoint inhibitors, often is limited by ineffective presentation of antigenic peptides that elicit T-cell-mediated anti-tumor cytotoxic responses. Manipulation of antigen presentation pathways is an emerging approach for enhancing the immunogenicity of tumors in immunotherapy settings. ER aminopeptidase 1 (ERAP1) is an intracellular enzyme that trims peptides as part of the system that generates peptides for binding to MHC class I molecules (MHC-I). We hypothesized that pharmacological inhibition of ERAP1 in cells could regulate the cellular immunopeptidome. To test this hypothesis, we treated A375 melanoma cells with a recently developed potent ERAP1 inhibitor and analyzed the presented MHC-I peptide repertoire by isolating MHC-I, eluting bound peptides, and identifying them using capillary chromatography and tandem mass spectrometry (LC-MS/MS). Although the inhibitor did not reduce cell-surface MHC-I expression, it induced qualitative and quantitative changes in the presented peptidomes. Specifically, inhibitor treatment altered presentation of about half of the total 3204 identified peptides, including about one third of the peptides predicted to bind tightly to MHC-I. Inhibitor treatment altered the length distribution of eluted peptides without change in the basic binding motifs. Surprisingly, inhibitor treatment enhanced the average predicted MHC-I binding affinity, by reducing presentation...
Source: Cancer Immunology, Immunotherapy - Category: Cancer & Oncology Source Type: research

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ock PRAME or PReferentially expressed Antigen in Melanoma is a testis-selective cancer testis antigen (CTA) with restricted expression in somatic tissues and re-expression in various cancers. It is one of the most widely studied CTAs and has been associated with the outcome and risk of metastasis. Although little is known about its pathophysiological function, PRAME has gained interest as a candidate target for immunotherapy. This review provides an update on our knowledge on PRAME expression and function in healthy and malignant cells and the current immunotherapeutic strategies targeting PRAME with their specific cha...
Source: Cancers - Category: Cancer & Oncology Authors: Tags: Review Source Type: research
Publication date: Available online 11 July 2019Source: American Journal of Kidney DiseasesAuthor(s): Roman Shingarev, Ilya G. GlezermanImmunologic control of malignancy has long been recognized as an important determinant of disease progression. Recent advances in immunology have led to the focus on several mechanisms that can be targeted to achieve tumor suppression. In particular, checkpoint inhibition has evolved in less than a decade to become one of the most important strategies in cancer therapy, with a meaningful improvement in patient survival. Six agents have been approved for clinical use to date and many more ar...
Source: American Journal of Kidney Diseases - Category: Urology & Nephrology Source Type: research
ConclusionThis case illustrates that a fulminant response to combined checkpoint inhibition is possible after progression after anti-PD-1 monotherapy and a severe irAE.
Source: Journal for Immunotherapy of Cancer - Category: Cancer & Oncology Source Type: research
ConclusionClinicians prescribing ICIs should be aware that SOT recipients are at risk of transplant rejection as a result of T cell activation. Dd-cfDNA is a sensitive biomarker and should be further studied for early detection of transplant rejection. Immunological analysis of the kidney explant showed marked graft infiltration with alloreactive PD-1+ cytotoxic T cells that were saturated with nivolumab.
Source: Journal for Immunotherapy of Cancer - Category: Cancer & Oncology Source Type: research
ConclusionHigh TMB,>  50% decrease of cell-free DNA concentration, and undetectable ctDNA at first follow-up seem to be associated with response and overall survival under combined immunotherapy. The evaluation of ctDNA and cell-free DNA three weeks after treatment initiation may be suitable for early assessment of ef ficacy of immunotherapy.
Source: Journal for Immunotherapy of Cancer - Category: Cancer & Oncology Source Type: research
Metastatic melanoma treatment has dramatically changed in the last few years, having a breakthrough with the introduction of targeted agents and immunotherapy. PD-1/PD-L1 pathway is one of the physiologic mechanisms of peripheral immune tolerance, but it also represents a mechanism of tumor immune escape. PD-1/PD-L1 inhibitors represent new immune-checkpoint drugs currently used in metastatic melanoma treatment. Resistance to PD-1/PD-L1 axis blockade, which is the main cause of therapeutic failure during therapeutic use of these drugs, could be linked to several mechanism of immune escape. In fact, other inhibitory recepto...
Source: Current Cancer Therapy Reviews - Category: Cancer & Oncology Source Type: research
arvajal Metastatic disease from uveal melanoma occurs in almost 50% of patients suffering from this ocular tumour, with median survival from development of symptoms being around 1 year. In contrast to cutaneous melanoma, kinase inhibitors and immune checkpoint inhibitors are usually ineffective in patients with metastatic uveal melanoma. Tebentafusp is a novel form of immunotherapy based on the immune-mobilising monoclonal T cell receptor against cancer (ImmTAC) platform, which comprises a soluble T cell receptor that is fused to an anti-CD3 single-chain variable fragment. The T cell receptor domain of tebentafusp targ...
Source: Cancers - Category: Cancer & Oncology Authors: Tags: Review Source Type: research
CONCLUSION: This large, multivariate analysis demonstrated that antibiotic use is an independent negative predictor of PFS and OS in patients with advanced cancer treated with ICIs. This study highlighted worse treatment outcomes from patients with cumulative (multiple or prolonged courses) antibiotic use, which warrants further investigation and may subsequently inform clinical practice guidelines advocating careful use of antibiotics. IMPLICATIONS FOR PRACTICE: Antibiotic use is negatively associated with treatment outcomes of immune checkpoint inhibitors (ICI) in advanced cancer. Cumulative antibiotic use is associ...
Source: The Oncologist - Category: Cancer & Oncology Authors: Tags: Oncologist Source Type: research
ConclusionsThis study explores the immunological mechanism of the combination between an oncolytic adenovirus and a DNA vaccine against melanoma. It demonstrates that the use of a rational combination therapy involving DNA vaccination could overcome its poor immunogenicity. In this way, it will be possible to exploit the great potential of DNA vaccination, thus allowing a larger use in the clinic.
Source: Journal for Immunotherapy of Cancer - Category: Cancer & Oncology Source Type: research
ConclusionsSevere CPI ‐related GEC typically manifests within 3 months of immunotherapy exposure. Rates of second‐line immunosuppression and readmission for recrudescence were high. CTCAE grade did not capture the degree of severity in our cohort. Second‐line immunosuppression was not associated with poorer oncolo gic outcomes; however, early corticosteroid exposure was associated with decreased PFS. Further investigation is warranted.
Source: Cancer Medicine - Category: Cancer & Oncology Authors: Tags: ORIGINAL RESEARCH Source Type: research
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