Inflammatory cell infiltrates in advanced metastatic uveal melanoma

Beyond Immune Checkpoint Inhibitors: Emerging Targets in Melanoma Therapy

PURPOSE OF REVIEW

This review provides a comprehensive update on recent advancements in melanoma treatment by highlighting promising therapeutics with an aim to increase awareness of novel interventions currently in development.

RECENT FINDINGS

Over the last decade there has been considerable expansion of the previously available treatment options for patients with melanoma. In particular, novel immunotherapeutics have been developed to expand on the clinical advancements brought by BRAF targeting and immune checkpoint inhibitors. Despite the success of checkpoint inhibitors there remains an unmet need for patients that do not respond to treatment. This review delves into the latest advancements in novel checkpoint inhibitors, cytokines, oncolytic viruses, vaccines, bispecific antibodies, and adoptive cell therapy. Preclinical experiments and early-stage clinical trials studies have demonstrated promising results for these therapies, many of which have moved into pivotal, phase 3 studies.

Implications of LAG3 and CTLA4 immune checkpoints beyond PD-1/PD-L1 as a potential target in determining the prognosis of uveal melanoma patients

BackgroundResponse rate of PD-1/PD-L1 immunotherapeutic blockade agents in uveal melanoma (UM) is poor. Lymphocyte activation gene 3 (LAG3) and cytotoxic T-lymphocyte-associated protein 4 (CTLA4) are the two promising immune checkpoint targets. Therefore, our aim was to explore at how these proteins were expressed in tumour tissue and serum, as well as their prognostic implications in UM.

METHODS

The expression of LAG3, CTLA-4, CD3, CD4, CD8 and FOXP3 was determined by immunohistochemistry in 54 enucleated UM tissue samples. mRNA expression level of LAG3 and CTLA-4 was determined by quantitative real-time PCR and corroborated by western blotting. Furthermore, soluble form of LAG3, CTLA-4 and CCR8 expression in serum was measured in 40 UM patients using ELISA.

RESULT

The expression of LAG3, CTLA-4, CD3, CD4, CD8 and FOXP3 was observed in 30%, 33%, 41%, 35%, 50% and 39% of the cases, respectively. Loss of nBAP1 expression was significantly correlated with CD8+expression (p=0.012) but not with tumour infiltrating lymphocytes. LAG3 and CTLA-4 mRNA levels were higher in UM compared with normal uveal tissues. Higher LAG3 expression with CD8+expression was associated with lower metastasis-free survival (MFS) (p=0.049), but not with CTLA-4 in UM patients. MFS rate was reduced in patients having lower levels of CCR8 protein (p=0.050) and increased level of LAG3 protein (p=0.001).

CONCLUSION

Our findings suggest that higher levels of LAG3 in UM with histopathologically high-risk parameters predict high metastatic potential and that it could be used as a targeted immunotherapy alone or in combination with PD-1/PD-L1 blockade agents.

The Future of Checkpoint Inhibitors in Uveal Melanoma: A Narrative Review

INTRODUCTION

Immune checkpoint inhibitors have made tremendous progress over the last decade in the treatment of cutaneous melanoma, but their application in uveal melanoma treatment is less successful, owing in part to the immunological privilege of the eye and the liver, the most frequent site of metastasis. Nevertheless, the therapeutic outcomes reported currently are less pessimistic.

METHODS

In this review, we provide an overview of recent studies of immune checkpoint inhibitors in uveal melanoma and its metastasis and classify studies in this field into three groups: monotherapy of immune checkpoint inhibitors, dual-agent immune checkpoint inhibitors, and immune checkpoint inhibitors combined with other systemic or regional therapies.

RESULTS

Briefly, monotherapy with immune checkpoint inhibitors performed poorly. Dual-agent immune checkpoint inhibitors had slightly better outcomes than traditional treatments, especially in specific patient populations. As for the combination therapy, the combination with other systemic therapies did not show superiority over dual-agent immune checkpoint inhibitors, but combination with hepatic regional therapies was quite promising. Moreover, research on emerging checkpoints is currently limited to the stage of mechanistic studies.

CONCLUSION

We propose that immune checkpoint inhibitors remain alternative treatments for patients with uveal melanoma, but factors such as cost-effectiveness should also be taken into account. The combination therapy with immune checkpoint inhibitors deserves to be further explored.

Identification and validation of a costimulatory molecule-related signature to predict the prognosis for uveal melanoma patients

Uveal melanoma (UVM) is the most common primary tumor in adult human eyes. Costimulatory molecules (CMs) are important in maintaining T cell biological functions and regulating immune responses. To investigate the role of CMs in UVM and exploit prognostic signature by bioinformatics analysis. This study aimed to identify and validate a CMs associated signature and investigate its role in the progression and prognosis of UVM. The expression profile data of training cohort and validation cohort were downloaded from The Cancer Genome Atlas (TCGA) dataset and the Gene Expression Omnibus (GEO) dataset. 60 CM genes were identified, and 34 genes were associated with prognosis by univariate Cox regression. A prognostic signature was established with six CM genes. Further, high- and low-risk groups were divided by the median, and Kaplan-Meier (K-M) curves indicated that high-risk patients presented a poorer prognosis. We analyzed the correlation of gender, age, stage, and risk score on prognosis by univariate and multivariate regression analysis. We found that risk score was the only risk factor for prognosis. Through the integration of the tumor immune microenvironment (TIME), it was found that the high-risk group presented more immune cell infiltration and expression of immune checkpoints and obtained higher immune scores. Enrichment analysis of the biological functions of the two groups revealed that the differential parts were mainly related to cell-cell adhesion, regulation of T-cell activation, and cytokine-cytokine receptor interaction. No differences in tumor mutation burden (TMB) were found between the two groups. GNA11 and BAP1 have higher mutation frequencies in high-risk patients. Finally, based on the Genomics of Drug Sensitivity in Cancer 2 (GDSC2) dataset, drug sensitivity analysis found that high-risk patients may be potential beneficiaries of the treatment of crizotinib or temozolomide. Taken together, our CM-related prognostic signature is a reliable biomarker that may provide ideas for future treatments for the disease.

Impact of Nintedanib and Anti-Angiogenic Agents on Uveal Melanoma Cell Behavior

Purpose

The purpose of this study was to investigate the direct impact of the combined angiokinase inhibitor nintedanib as well as the anti-angiogenic agents ranibizumab, bevacizumab, and aflibercept on the primary uveal melanoma (UM) cell line Mel270 and liver metastasis UM cell line OMM2.5.

Methods

The metabolic activity, viability, and oxidative stress levels were analyzed by the Thiazolyl Blue Tetrazolium Bromide (MTT), LIVE/DEAD, and reactive oxygen species (ROS) assays. Expression of intracellular VEGF-A165 and VEGF receptor-2 was detected by immunofluorescent staining. The secretion of VEGF-A165 into the cell culture supernatants was evaluated by VEGF-A165 ELISA.

Results

Nintedanib, at a concentration of 1 µg/mL, resulted in a median reduction of metabolic activity (for Mel270 of approximately 38% and for OMM2.5 of 46% compared to the untreated control) without exerting toxicity in either cell line, whereas the other 3 substances did not result in any changes (which also means that none of the 4 substances led to an increased cell death). Moreover, nintedanib (1 µg/mL) induced oxidative stress in the Mel270 by approximately 1.2 to 1.5-fold compared to the untreated control, but not the OMM2.5 cells.

Conclusions

Nintedanib could suppress the growth of UM cells in a concentration-dependent manner. The metastatic UM cell line OMM2.5 was not sensitive to the pro-oxidant activity of nintedanib. This study was the first to investigate nintedanib in the context of UM. We propose further investigation of this substance to elucidate its effects on this tumor entity with the hope of identifying advantageous therapeutic options for future adjuvant tumor therapies.

Immunogenic profiling of metastatic uveal melanoma discerns a potential signature related to prognosis

BACKGROUND

Uveal melanoma (UM) is an aggressive intraocular malignant tumor. The present study aimed to identify the key genes associated with UM metastasis and established a gene signature to analyze the relationship between the signature and prognosis and immune cell infiltration. Later, a predictive model combined with clinical variables was developed and validated.

METHODS

Two UM gene expression profile chip datasets were downloaded from TCGA and GEO databases. Immune-related genes (IRGs) were obtained from IMPORT database. First, these mRNAs were intersected with IRGs, and weighted gene co-expression network analysis (WGCNA) was used to identify the co-expression of genes primarily associated with metastasis of UM. Univariate Cox regression analysis screened the genes related to prognosis. LASSO-Cox established a risk score to distinguish high-risk group and low-risk group. Then the GSEA enrichment pathway and immune cell infiltration of the two groups were compared. And combined with clinical variables, a predictive model was constructed. The time-dependent receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis (DCA) curve were used to verify the stability and accuracy of the final predictive model, and a nomogram was then drawn.

RESULTS

The MEblack, MEpurple, and MEblue modules were significantly associated with the metastasis of UM patients (P value < 0.001, = 0.001, = 0.022, respectively). Four genes (UBXN2B, OTUD3, KAT8, LAMTOR2) were obtained by Pearson correlation analysis, weighted gene correlation network analysis (WGCNA), univariate Cox, and LASSO-Cox. And a novel prognostic risk score was established. Immune-related prognostic signature can well classify UM patients into high-risk and low-risk groups. Kaplan-Meier curve showed that the OS of high-risk patients was worse than that of low-risk patients. In addition, the risk score played an important role in evaluating the signaling pathway and immune cell infiltration of UM patients in high-risk and low-risk groups. Both the training set and validation set of the model showed good predictive accuracy in the degree of differentiation and calibration (e.g., 1-year overall survival: AUC = 0.930 (0.857-1.003)). Finally, a nomogram was established to serve in clinical practice.

SIGNIFICANCE

UM key gene signature and prognosis predictive model might provide insights for further investigation of the pathogenesis and development of UM at the molecular level, and provide theoretical basis for determining new prognostic markers of UM and immunotherapy.

Characterisation of the protein expression of the emerging immunotherapy targets VISTA, LAG-3 and PRAME in primary uveal melanoma: insights from a southern French patient cohort

Uveal melanoma (UM) is the most common intraocular tumour in adults, with dismal prognosis once metastases develop, since therapeutic options for the metastatic disease are ineffective. Over the past decade, novel cancer therapies based on immunotherapy have changed the landscape of treatment of different forms of cancer leading to many hopes of improvement in patient overall survival (OS). VISTA, LAG-3 and PRAME are novel promising targets of immunotherapy that have recently gained attention in different solid tumours, but whose relevance in UM remained to be comprehensively evaluated until now. Here, we studied the protein expression of VISTA, LAG-3 and PRAME using immunohistochemistry in representative whole tissue sections from primary UM cases in a cohort of 30 patients from a single centre (Nice University Hospital, Nice, France). The expression of each of these markers was correlated with different clinical and pathological parameters, including onset of metastases and OS. We demonstrated the protein expression of VISTA and LAG-3 in small lymphocytes infiltrating the tumour, while no expression of the proteins was detected in UM cells. For PRAME, nuclear expression was observed in UM cells, but no expression in tumour infiltrating immune cells was identified. Increased levels of VISTA expression in tumour infiltrating lymphocytes (TILs) were associated with nuclear BAP1 expression and better prognosis. Higher levels of LAG-3 in TILs were associated with higher levels of CD8-positive TILs. PRAME nuclear positivity in melanoma cells was associated with epithelioid cell dominant (>90%) UM histological subtype, higher mitotic numbers and a higher percentage of chromosome 8q gain. This study proposes VISTA as a novel relevant immune checkpoint molecule in primary UM and contributes to confirm LAG-3 and PRAME as potentially important immunotherapy targets in the treatment of UM patients, helping to expand the number of immunotherapy candidate molecules that are relevant to modulate in this aggressive cancer.

An update on inflammation in uveal melanoma

Uveal melanoma (UM) is the primary ocular cancer with upto 50% of patients dying from metastasis. Although rare, it is deadly as patients with metastatic UM seldom survive beyond 18 months after diagnosis. Chemotherapeutics have no proven efficacy, including immunotherapies that have been tried as current treatment options but produce marginal improvement in overall survival for UM patients. While therapeutics are low in efficacy, there is an urgent need to explore novel targets in the treatment of UM. This review provides an update on the contribution of inflammation to UM with a focus on exploring potential therapeutic targets related to the inflammatory tumour microenvironment. As a tumour promoting event, inflammation is one of the hallmarks of cancers. The presence of the inflammatory phenotype characterised by the abundance of immune mediators and proinflammatory cytokines surrounding UM tumours, is a potential area to explore novel therapeutic targets. Despite decades of investigation regarding the role UM tumour microenvironment has played, that of inflammation in UM progression remains poorly understood. With advancement of technologies, an understanding of the prognosis of UM has been accelerated. Excitingly, novel therapeutic targets related to the inflammatory tumour microenvironment have been identified and relevant studies are underway in their preliminary phases, illustrating optimistic results.

Immunohistochemical characterisation of the immune landscape in primary uveal melanoma and liver metastases

BACKGROUND

The immune landscape of uveal melanoma liver metastases (UMLM) has not been sufficiently studied.

METHODS

Immune cell infiltrates (ICIs), PD-1 and PD-L1 were characterised in 62 UMLM and 28 primary uveal melanomas (PUM). ICI, PD-1 and PD-L1 were scored as: (1) % tumoral area occupied by tumour-infiltrating lymphocytes or macrophages (TILs, TIMs) and (2) % perTumoral (perT) area. ICIs and other variables including histopathologic growth patterns (HGPs), replacement and desmoplastic, of UMLM were analysed for their prognostic value.

RESULTS

ICIs recognised by haematoxylin-eosin-saffron (HES) and IHC (e.g., T cells (CD3), B cells (CD20). Macrophages (CD68), (CD163), were primarily localised to the perT region in PUM and UMLM and were more conspicuous in UMLM. HES, CD3, CD4, FoxP3, CD8, CD20, PD-1 TILs were scant (<5%). TIMs were more frequent, particularly in UMLM than in PUM. Both CD68+ TIMs and HGPs remained significant on multivariate analysis, influencing overall (OS) and metastasis-specific overall survival (MSOS). CD68 + , CD163+ and CD20+ perT infiltrates in UMLM predicted increased OS and MSOS on univariate analysis.

CONCLUSIONS

TILs and PD-L1 have no predictive value in PUM or UMLM. CD68+ and CD163+TIMs, CD20+ perT lymphocytes, and HGPs are important prognostic factors in UMLMs.

The immune checkpoint VISTA is associated with prognosis in patients with malignant uveal melanoma

Introduction

Uveal melanoma (UM) is a rare yet deadly tumor. It is known for its high metastatic potential, which makes it one of the most aggressive and lethal cancers. Recently, immune checkpoints such as Programmed cell Death protein-1 (PD1) and Cytotoxic T-Lymphocyte-Associated significantly increasing patient survival in multiple human cancers, especially cutaneous melanoma. However, patients with UMs were excluded from these studies because of their molecular characteristics, which tend to be widely different from those of cutaneous melanoma. This study aimed to analyze the expression of V domain Ig Suppressor T-cell Activation (VISTA), a novel immune checkpoint, to evaluate its prognosis significance and its correlation with PD1 and CTLA-4.

Methods

Evaluation of VISTA, CTLA-4, and PD1 expression was performed through TCGA database analysis and immunohistochemistry using two independent cohorts with primary malignant UM.

Results and discussion

Our results showed that VISTA expression was associated with tumor aggressiveness, T cell exhaustion, and the shortest median overall survival among patients. Surprisingly, PD1 protein expression was negative in all patients, whereas CTLA-4 expression was high in patients with advanced stages. Our findings suggest that VISTA may be a prognostic marker and an attractive treatment strategy for immunotherapy in patients with UM. Exploring its expression profile may predict response to immunotherapy and may lead to the improvement of precision therapy in malignant uveal melanoma patients.

Tebentafusp: a first-in-class treatment for metastatic uveal melanoma

Tebentafusp is a first-in-class immunotherapy agent that comprises an engineered T-cell receptor targeting a gp100 epitope presented by human leukocyte antigen-A*02:01 cells, fused to an anti-CD3 single-chain variable fragment. Tebentafusp is both the first bispecific T-cell engager to show efficacy in the treatment of advanced solid cancer and the first anti-cancer treatment to demonstrate an overall survival benefit in patients with uveal melanoma (UM). This review article will focus on the clinical development of tebentafusp, the mechanism of action and resultant evolution of the management of advanced UM.

Advances in the clinical management of uveal melanoma

Melanomas arising in the uveal tract of the eye are a rare form of the disease with a biology and clinical phenotype distinct from their more common cutaneous counterparts. Treatment of primary uveal melanoma with radiotherapy, enucleation or other modalities achieves local control in more than 90% of patients, although 40% or more ultimately develop distant metastases, most commonly in the liver. Until January 2022, no systemic therapy had received regulatory approval for patients with metastatic uveal melanoma, and these patients have historically had a dismal prognosis owing to the limited efficacy of the available treatments. A series of seminal studies over the past two decades have identified highly prevalent early, tumour-initiating oncogenic genomic aberrations, later recurring prognostic alterations and immunological features that characterize uveal melanoma. These advances have driven the development of a number of novel emerging treatments, including tebentafusp, the first systemic therapy to achieve regulatory approval for this disease. In this Review, our multidisciplinary and international group of authors summarize the biology of uveal melanoma, management of primary disease and surveillance strategies to detect recurrent disease, and then focus on the current standard and emerging regional and systemic treatment approaches for metastatic uveal melanoma.

Construction and Verification of the Molecular Subtype and a Novel Prognostic Signature Based on Inflammatory Response-Related Genes in Uveal Melanoma

The significance of inflammation in tumorigenesis and progression has become prominent. This study aimed to construct and validate the molecular subtype and a novel prognostic signature based on inflammatory response-related genes in uveal melanoma (UM). Patients from the TCGA, GSE84976, and GSE22138 UM cohorts were enrolled. According to the consensus cluster analysis, patients were divided into two molecular subtypes, namely IC1 and IC2. Survival curves showed that patients in IC1 had a better prognosis. The IC2 subgroup had higher levels of immune cell infiltration and more enriched immunological pathways. There were statistical differences in the immune-inflammation microenvironment, immune checkpoint genes expression, and drug sensitivity. The prognostic signature constructed based on inflammatory response-related genes exhibited a stable predictive power. Multivariate analysis confirmed that the signature was a prognostic factor independent of clinical characteristics. Functional analyses showed that the high-risk group was associated with immunological response, inflammatory cell activation, and tumor-related signal pathways. The riskscore had a negative relationship with tumor purity and was positively correlated with immune and stromal scores. Furthermore, the prognostic signature could sensitively predict the response to drug treatments. In conclusion, the prognostic signature might aid in stratifying patients at risk premised on the prognosis and immunotherapy sensitivity.

Using the Chick Embryo Model to Examine the Effects of Hypoxia Pre-conditioning of Uveal Melanoma Cells on Tumor Growth and Metastasis

PURPOSE

Highly dynamic oxygen gradients occur within tumors that can result in a hypoxic response, contributing to tumor progression and metastasis. Evidence in uveal melanoma (UM) suggests an upregulated hypoxia response in some poor prognosis UM characterized by HIF1α signaling. We aimed to investigate the effects of exposure to hypoxia on tumor growth and dissemination in the chick embryo chorioallantoic membrane (CAM) model.

METHODS

UM cell lines (MP41, 92.1, MP46, and OMM1) were grown in two-dimensional culture and pre-exposed to hypoxic (1% O₂) conditions for 72 h. The effects of this hypoxia pre-conditioning on cell number and clonogenicity as compared with 21% O₂ ("normoxia") were investigated prior to transplantation of the cells onto the CAM. Nodule-forming efficiency (NFE), nodule size, and the presence/absence of tumor cell dissemination were determined macroscopically and histologically.

RESULTS

Exposure of UM cell lines to hypoxia upregulated HIF1α expression compared to cells cultured in normoxia. A 72-h pre-exposure to hypoxia significantly reduced cell number and clonogenicity in the MP41 and OMM1 cell lines while it had little effect in 92.1 and MP46 cells. When 72-h hypoxia pre-conditioned cells were grown in three-dimensions on the CAM, a reduction in NFE and nodule size was observed when compared with normoxic UM cells. All nodules were composed of proliferating (Ki-67+) Melan-A + cells and displayed chick blood vessel recruitment. Spread of UM cells into the adjacent CAM was observed; however, dissemination to the chick liver was only seen with 92.1 cells grown under normoxia.

CONCLUSIONS

Hypoxia pre-conditioning does not appear to drive a metastatic phenotype in UM; however, further understanding of how oxygen dynamics within the tumor microenvironment regulates HIF1 signaling is needed to determine whether inhibitors of HIF signaling represent a therapeutic option in metastatic UM.

Digital Quantification of Intratumoral CD8+ T-Cells Predicts Relapse and Unfavorable Outcome in Uveal Melanoma

Although it is a disease that occurs mainly in the Caucasian population, uveal melanoma (UM) is the most common primary intraocular tumor in adults. Here, we used digital pathology and image analysis for the diagnosis of UM and the prediction of the prognosis. Our retrospective study included a total of 404 histopathological slides from 101 patients. A digital image acquisition and quantitative analysis of tissue immune biomarkers (CD4, CD8, CD68, CD163) were performed. A negative impact of the intratumoral CD8 positive cell density higher than 13.3 cells/mm² was detected for both RFS (HR 2.08, 95% Cl 1.09 to 3.99, p = 0.027) and OS (HR 3.30, 95% CI 1.58 to 6.88, p = 0.001). Moreover, we confirmed that older age and stage III were independent negative prognostic factors for both RFS and OS. Our results suggest that a specific distribution profile of CD8 in UM might predict the risk of relapse and death, with potential implications for determining which subgroups of UMs are amenable to specific pharmacological treatment regimens.

Extracellular Vesicles from Ocular Melanoma Have Pro-Fibrotic and Pro-Angiogenic Properties on the Tumor Microenvironment

Uveal melanoma (UM) is the most common primary intraocular tumor and often spreads to the liver. Intercellular communication though extracellular vesicles (EVs) plays an important role in several oncogenic processes, including metastasis, therapeutic resistance, and immune escape. This study examines how EVs released by UM cells modify stellate and endothelial cells in the tumor microenvironment. The surface markers, and the concentration and size of EVs derived from UM cells or choroidal melanocytes were characterized by high-resolution flow cytometry, electron microscopy, and Western blotting. The selective biodistribution of EVs was studied in mice by fluorescence imaging. The activation/contractility of stellate cells and the tubular organization of endothelial cells after exposure to melanomic EVs were determined by traction force microscopy, collagen gel contraction, or endothelial tube formation assays. We showed that large EVs from UM cells and healthy melanocytes are heterogenous in size, as well as their expression of phosphatidylserine, tetraspanins, and Tsg101. Melanomic EVs mainly accumulated in the liver and lungs of mice. Hepatic stellate cells with internalized melanomic EVs had increased contractility, whereas EV-treated endothelial cells developed more capillary-like networks. Our study demonstrates that the transfer of EVs from UM cells leads to a pro-fibrotic and pro-angiogenic phenotype in hepatic stellate and endothelial cells.

GOLM1 is related to the inflammatory/immune nature of uveal melanoma and acts as a promising indicator for prognosis and immunotherapy response

Purpose: Inflammatory/immune-related features are associated with the immunotherapy and prognosis of uveal melanoma (UVM). In this study, we systematically analyzed the correlation between GOLM1 and the inflammatory/immune nature of UVM and explored its potential value in predicting prognosis and guiding immunotherapy for UVM patients.

Methods: A total of 143 UVM patients were enrolled in the current study. The differentially expressed genes between the GOLM1-low expression (LEXP) and GOLM1-high expression (HEXP) subgroups were calculated by the “limma” package and further annotated to reveal the key pathways by the “ClusterProfiler” package. Immunocyte infiltration was evaluated by single-sample gene set enrichment analysis, while the potential response to immunotherapy was realized by subclass mapping analysis. Moreover, tumor tissue sections from 23 UVM patients were collected and stained for GOLM1 (1:300; cat# DF8100, Affinity Biosciences), PD-L1 (1:250; cat# ab213524, Abcam), PD-1 (1:100; cat# ab52587, Abcam), CTLA-4 (1:300; cat# DF6793, Affinity Biosciences), and IFN-γ (1:300; cat# DF6045, Affinity Biosciences).

Results: We found that higher expression of GOLM1 correlated with an unfavorable prognosis in UVM patients. Multivariate Cox regression analysis suggested that GOLM1 served as a prognostic factor independent of clinicopathological parameters. Notably, we found that the expression of PD-1, PD-L1, IFN-γ, and CTLA4 was higher in the GOLM1-high subgroup than in the GOLM1-low expression subgroup at the mRNA level and was subsequently validated at the protein level by immunohistochemistry. Gene pattern and SubMap analyses confirmed the indicator role of GOLM1 in predicting immunotherapy response in UVM.

Conclusion: Taken together, GOLM1 is a novel prognostic marker, and it can be employed to predict the overall survival outcomes and treatment responses of anti-PD-1/PD-L1 and anti-CTLA4 therapies for UVM patients.

Tebentafusp for the treatment of metastatic uveal melanoma

Uveal melanoma is a rare disease; nevertheless, it is the most common primary intraocular malignancy among adults. Approximately half of affected patients will suffer from metastatic disease, mostly to the liver. No standard-of-care treatment exists for these patients. Median progression-free survival and overall survival for all types of treatment, including checkpoint inhibitors, have remained poor. However, the most recent phase III study results for tebentafusp, a member of a new-in-class molecule, are raising hopes for stage IV uveal melanoma patients. In this review, we examine the current literature, focusing on the most recent trial results for this new reagent. We evaluate the latest clinical results for tebentafusp and aim to shed light on its immunological strategy.

Prognostic Biomarkers in Uveal Melanoma: The Status Quo, Recent Advances and Future Directions

Simple Summary

Although rare, uveal melanoma (UM) is the most common cancer that develops inside adult eyes. The prognosis is poor, since 50% of patients will develop lethal metastases in the first decade, especially to the liver. Once metastases are detected, life expectancy is limited, given that the available treatments are mostly unsuccessful. Thus, there is a need to find methods that can accurately predict UM prognosis and also effective therapeutic strategies to treat this cancer. In this manuscript, we initially compile the current knowledge on epidemiological, clinical, pathological and molecular features of UM. Then, we cover the most relevant prognostic factors currently used for the evaluation and follow-up of UM patients. Afterwards, we highlight emerging molecular markers in UM published over the last three years. Finally, we discuss the problems preventing meaningful advances in the treatment and prognostication of UM patients, as well as forecast new roadblocks and paths of UM-related research.

Abstract

Uveal melanoma (UM) is the most common malignant intraocular tumour in the adult population. It is a rare cancer with an incidence of nearly five cases per million inhabitants per year, which develops from the uncontrolled proliferation of melanocytes in the choroid (≈90%), ciliary body (≈6%) or iris (≈4%). Patients initially present either with symptoms like blurred vision or photopsia, or without symptoms, with the tumour being detected in routine eye exams. Over the course of the disease, metastases, which are initially dormant, develop in nearly 50% of patients, preferentially in the liver. Despite decades of intensive research, the only approach proven to mildly control disease spread are early treatments directed to ablate liver metastases, such as surgical excision or chemoembolization. However, most patients have a limited life expectancy once metastases are detected, since there are limited therapeutic approaches for the metastatic disease, including immunotherapy, which unlike in cutaneous melanoma, has been mostly ineffective for UM patients. Therefore, in order to offer the best care possible to these patients, there is an urgent need to find robust models that can accurately predict the prognosis of UM, as well as therapeutic strategies that effectively block and/or limit the spread of the metastatic disease. Here, we initially summarized the current knowledge about UM by compiling the most relevant epidemiological, clinical, pathological and molecular data. Then, we revisited the most important prognostic factors currently used for the evaluation and follow-up of primary UM cases. Afterwards, we addressed emerging prognostic biomarkers in UM, by comprehensively reviewing gene signatures, immunohistochemistry-based markers and proteomic markers resulting from research studies conducted over the past three years. Finally, we discussed the current hurdles in the field and anticipated the future challenges and novel avenues of research in UM.

Uveal Melanoma Metastasis

Uveal melanoma (UM) is characterized by relatively few, highly incident molecular alterations and their association with metastatic risk is deeply understood. Nevertheless, this knowledge has so far not led to innovative therapies for the successful treatment of UM metastases or for adjuvant therapy, leaving survival after diagnosis of metastatic UM almost unaltered in decades. The driver mutations of UM, mainly in the G-protein genes GNAQ and GNA11, activate the MAP-kinase pathway as well as the YAP/TAZ pathway. At present, there are no drugs that target the latter and this likely explains the failure of mitogen activated kinase kinase inhibitors. Immune checkpoint blockers, despite the game changing effect in cutaneous melanoma (CM), show only limited effects in UM probably because of the low mutational burden of 0.5 per megabase and the unavailability of antibodies targeting the main immune checkpoint active in UM. The highly pro-tumorigenic microenvironment of UM also contributes to therapy resistance. However, T-cell redirection by a soluble T-cell receptor that is fused to an anti-CD3 single-chain variable fragment, local, liver specific therapy, new immune checkpoint blockers, and YAP/TAZ specific drugs give new hope to repeating the success of innovative therapy obtained for CM.

Loss of polycomb repressive complex 1 activity and chromosomal instability drive uveal melanoma progression

Chromosomal instability (CIN) and epigenetic alterations have been implicated in tumor progression and metastasis; yet how these two hallmarks of cancer are related remains poorly understood. By integrating genetic, epigenetic, and functional analyses at the single cell level, we show that progression of uveal melanoma (UM), the most common intraocular primary cancer in adults, is driven by loss of Polycomb Repressive Complex 1 (PRC1) in a subpopulation of tumor cells. This leads to transcriptional de-repression of PRC1-target genes and mitotic chromosome segregation errors. Ensuing CIN leads to the formation of rupture-prone micronuclei, exposing genomic double-stranded DNA (dsDNA) to the cytosol. This provokes tumor cell-intrinsic inflammatory signaling, mediated by aberrant activation of the cGAS-STING pathway. PRC1 inhibition promotes nuclear enlargement, induces a transcriptional response that is associated with significantly worse patient survival and clinical outcomes, and enhances migration that is rescued upon pharmacologic inhibition of CIN or STING. Thus, deregulation of PRC1 can promote tumor progression by inducing CIN and represents an opportunity for early therapeutic intervention.

The molecular underpinnings driving uveal melanoma (UM) progression are unknown. Here the authors show that loss of Polycomb Repressive Complex 1 triggers chromosomal instability, which promotes inflammatory signaling and migration in UM.

Long-Term Maintained Response to Selective Internal Radiation Therapy in an Oligometastatic Uveal Melanoma Patient Treated with Concomitant Anti-PD-1 Therapy

Uveal melanoma (UM) is a primary neoplasm of the eye arising from the melanocytes residing in the iris, ciliary body or choroid. It is the most frequent intraocular malignancy and often determines metastases at distant sites, with a peculiar tropism for the liver. Metastatic UM has a poor prognosis, as any treatment affects the natural course of this fatal disease. Herein, we report a case of a UM metastatic to the liver in a 54 year-old female patient, initially treated with nivolumab without success. The patient was then scheduled for selective internal radiation therapy (SIRT) while continuing immunotherapy. This combination led to a complete and durable response and the patient is currently free of disease, two years after the diagnosis of the hepatic metastases. The association between SIRT and immunotherapy (IT) has very promising perspectives for metastatic UM, especially considering the disappointing or contradictory results of classic chemotherapies, IT alone and targeted therapies. Furthermore, this combination has been shown to have a good security profile. However, further studies are needed to confirm the efficacy of associating SIRT and IT and to clarify some unsolved problems, such as the timing of administration of these two therapies.

Bioinformatic Analysis Reveals Central Role for Tumor-Infiltrating Immune Cells in Uveal Melanoma Progression

Tumor-infiltrating immune cells are capable of effective cancer surveillance, and their abundance is linked to better prognosis in numerous tumor types. However, in uveal melanoma (UM), extensive immune infiltrate is associated with poor survival. This study aims to decipher the role of different tumor-infiltrating cell subsets in UM in order to identify potential targets for future immunotherapeutic treatment. We have chosen the TCGA-UVM cohort as a training dataset and GSE22138 as a testing dataset by mining publicly available databases. The abundance of 22 immune cell types was estimated using CIBERSORTx. Then, to determine the significance of tumor-infiltrating cell subsets in UM, we built a multicell type prognostic signature, which was validated in the testing cohort. The created signature was built upon the negative prognostic role of CD8+ T cells and M0 macrophages and the positive role of neutrophils. Based on the created signature score, we divided the patients into low- and high-risk groups. Kaplan-Meier, Cox, and ROC analyses demonstrated superior performance of our risk score compared to either clinical or pathologic characteristics of both cohorts. Further, we found the molecular pathways associated with cancer immunoevasion and metastasis to be enriched in the high-risk group, explaining both the lack of adequate immune surveillance despite increased infiltration of CD8+ T cells as well as the higher metastatic potential. Genes associated with tryptophan metabolism (IDO1 and KYNU) and metalloproteinases were among the most differentially expressed between the high- and low-risk groups. Our correlation analyses interpreted in context of published in vitro data strongly suggest the central role of CD8+ T cells in shifting the UM tumor microenvironment towards suppressive and metastasis-promoting. Therefore, we propose further investigations of IDO1 and metalloproteinases as novel targets for immunotherapy in lymphocyte-rich metastatic UM patients.

Clinical Trials in Metastatic Uveal Melanoma: Immunotherapy

BACKGROUND

Uveal melanoma (UM) is a rare subtype of melanoma that generally has a poor prognosis once it has metastasized. Clinical trials evaluating immune checkpoint inhibitors (ICIs) in UM have demonstrated response rates lower than those seen in cutaneous melanoma. Despite lower efficacy demonstrated in initial ICI studies, there are a number of ongoing clinical trials investigating novel immunotherapy approaches in UM.

SUMMARY

This review aims to summarize important ongoing clinical trials investigating immunotherapeutic approaches in UM and previous trials that have evaluated a number of immunologic interventions. A thorough clinical trial investigation was conducted through clinicaltrials.gov using the disease search terms "uveal melanoma" and "ocular melanoma," excluding non-immunotherapy-related trials. Here, we report on ICI, vaccine, adoptive T cells, and combination immunotherapy trials in UM.

KEY MESSAGES

There is an increasing effort in the search for new, effective therapies for this difficult-to-treat disease, with immunotherapeutic approaches being of particular interest. Increasing knowledge of UM biology and development of new biomarkers will direct future drug development and trial design.

Immune marker signature helps to predict survival in uveal melanoma

The detailed molecular function of tumor microenvironment (TEM) in uveal melanoma (UVM) remains unclear. This study generated the immune index and the stromal index scores by ESTIMATE algorithm based on RNA-sequencing data with 80 UVM patients. There was no correlation between the immune stromal index and clinical parameters. The differentially expressed genes related to the immune stromal index were calculated and were described by functional annotations and protein-protein interaction network diagrams. After univariate and multivariate Cox regression analyses, there were four genes (HLA-J, MMP12, HES6, and ADAMDEC1) with significant prognostic significance. The prognostic model was constructed using these four characteristic genes, and the KM curve and tROC curve were described to show that the model had a better ability to predict survival outcomes and prognosis. The verification results in GSE62075 showed that HLA-J and HES6 were expressed differently in the cancer group than in the non-cancer group. This study indicates that the risk signature based on the immune index can be used as an indicator to evaluate the prognosis of patients with UVM.

The immune cell landscape of metastatic uveal melanoma correlates with overall survival

BACKGROUND

Uveal melanoma (UM) represents the most common primary intra-ocular malignancy in adults. Up to 50% of the patients develop distant metastases within 10 years from diagnosis, with the liver as the most common site. Upon metastatization, life expectancy strongly reduces and immune checkpoint inhibitors that prove effective in cutaneous melanoma do not modify clinical outcome. To date, few studies have focused on deciphering the immunomodulatory features of metastatic UM microenvironment, and there are no prognostic models for clinical use. This highlights the urgent need to understand the delicate interplay between tumor and immune cells acting at the site of metastasis.

METHODS

We collected a patient cohort comprising 21 metastatic UM patients. Hepatic and extra-hepatic UM metastasis samples were studied by multiplex immunofluorescence to assess the tumor immune cell composition. Quantitative analyses were performed to correlate immune cell densities with treatment response, metastasis site and patient survival.

RESULTS

Compared to patients with progressive disease, those with controlled disease had a higher intra-tumoral/peritumoral ratio of CD8 + Granzyme B+ cells, higher density of intra-tumoral CD8+ cytotoxic T lymphocytes (CTL) and an increased percentage of UM cells in close proximity to T lymphocytes, reflecting a role of tumor-killing T cells in the disease. In liver metastases (LM), the intra-tumoral densities of CD163+ tumor-associated macrophages (TAM) and of total CD8+ T cells were higher than in extra-hepatic UM metastases, but the percentage of Granzyme B+ CTL was lower. Moreover, LM displayed more UM cells adjacent to both CTL and TAM, and also more T cells in proximity to TAM, all signs of an impaired immune response. The percentage of activated CTL within the tumor represented a prognostic indicator, as patients with a higher intra-tumoral percentage of CD8 + Granzyme B+ cells had the better outcome. A temptative Immunoscore was generated and proved capable to stratify patients with improved survival. Finally, CD4 + FoxP3+ T cells appeared a crucial population for response to immunotherapy.

CONCLUSION

The results of this study underly the clinical relevance and functional importance of composition and localization of antitumor effector cells for the progression of UM metastasis.

How to Make Immunotherapy an Effective Therapeutic Choice for Uveal Melanoma

Simple Summary

Despite improvements in the early identification and successful control of primary uveal melanoma, 50% of patients will develop metastatic disease with only marginal improvements in survival. This review focuses on the tumor microenvironment and the cross-talk between tumor and immune cells in a tumor characterized by low mutational load, the induction of immune-suppressive cells, and the expression of alternative immune checkpoint molecules. The choice of combining different strategies of immunotherapy remains a feasible and promising option on selected patients.

Abstract

Uveal melanoma (UM), though a rare form of melanoma, is the most common intraocular tumor in adults. Conventional therapies of primary tumors lead to an excellent local control, but 50% of patients develop metastases, in most cases with lethal outcome. Somatic driver mutations that act on the MAP-kinase pathway have been identified, yet targeted therapies show little efficacy in the clinics. No drugs are currently available for the G protein alpha subunitsGNAQ and GNA11, which are the most frequent driver mutations in UM. Drugs targeting the YAP–TAZ pathway that is also activated in UM, the tumor-suppressor gene BRCA1 Associated Protein 1 (BAP1) and the Splicing Factor 3b Subunit 1 gene (SF3B1) whose mutations are associated with metastatic risk, have not been developed yet. Immunotherapy is highly effective in cutaneous melanoma but yields only poor results in the treatment of UM: anti-PD-1 and anti-CTLA-4 blocking antibodies did not meet the expectations except for isolated cases. Here, we discuss how the improved knowledge of the tumor microenvironment and of the cross-talk between tumor and immune cells could help to reshape anti-tumor immune responses to overcome the intrinsic resistance to immune checkpoint blockers of UM. We critically review the dogma of low mutational load, the induction of immune-suppressive cells, and the expression of alternative immune checkpoint molecules. We argue that immunotherapy might still be an option for the treatment of UM.

Translation of single-cell transcriptomic analysis of uveal melanomas to clinical oncology

Uveal melanoma (UM) is an aggressive and deadly neoplasm. In recent decades, great efforts have been made to obtain a more comprehensive understanding of genetics, genomics and molecular changes in UM, enabling the identification of key cellular processes and signalling pathways. Still, there is no effective treatment for the metastatic disease. Intratumoural heterogeneity (ITH) is thought to be one of the leading determinants of metastasis, therapeutic resistance and recurrence. Crucially, tumours are complex ecosystems, where cancer cells, and diverse cell types from their microenvironment engage in dynamic spatiotemporal crosstalk that allows cancer progression, adaptation and evolution. This highlights the urgent need to gain insight into ITH in UM and its intersection with the microenvironment to overcome treatment failure. Here we provide an overview of the studies and technologies to study ITH in human UMs and tumour micro-environmental composition. We discuss how to incorporate ITH into clinical consideration for the purpose of advocating for new clinical management. We focus on the application of single-cell transcriptomic analysis and propose that understanding the driving forces and functional consequences of the observed tumour heterogeneity holds promise for changing the treatment paradigm of metastatic UMs, surmounting resistance and improving patient prognosis.

Immunotherapy in uveal melanoma: novel strategies and opportunities for personalized treatment

INTRODUCTION

Uveal melanoma (UM) is the most common intraocular cancer and represents a discrete subtype of melanoma. Metastatic disease, which occurs in half of patients, has a dismal prognosis. Immunotherapy with immune checkpoint inhibitors has produced promising results in cutaneous melanoma but has failed to show analogous efficacy in metastatic UM. This is attributable to UM's distinct genetics and its complex interaction with the immune system. Hence, more efficacious immunotherapeutic approaches are under investigation.

AREAS COVERED

We discuss those novel immunotherapeutic strategies in clinical and preclinical studies for advanced disease and which are thought to overcome the hurdles set by UM in terms of immune recognition. We also highlight the need to determine predictive markers in relation to these strategies to improve clinical outcomes. We used a simple narrative analysis to summarize the data. The search methodology is located in the Introduction.

EXPERT OPINION

Novel immunotherapeutic strategies focus on transforming immune excluded tumor microenvironment in metastatic UM to T cell inflamed. Preliminary results of approaches such as vaccines, adoptive cell transfer and other novel molecules are encouraging. Factors such as HLA compatibility and expression level of targeted antigens should be considered to optimize personalized management.

Applying Single-Cell Technology in Uveal Melanomas: Current Trends and Perspectives for Improving Uveal Melanoma Metastasis Surveillance and Tumor Profiling

Uveal melanoma (UM) is the most common primary adult intraocular malignancy. This rare but devastating cancer causes vision loss and confers a poor survival rate due to distant metastases. Identifying clinical and molecular features that portend a metastatic risk is an important part of UM workup and prognostication. Current UM prognostication tools are based on determining the tumor size, gene expression profile, and chromosomal rearrangements. Although we can predict the risk of metastasis fairly accurately, we cannot obtain preclinical evidence of metastasis or identify biomarkers that might form the basis of targeted therapy. These gaps in UM research might be addressed by single-cell research. Indeed, single-cell technologies are being increasingly used to identify circulating tumor cells and profile transcriptomic signatures in single, drug-resistant tumor cells. Such advances have led to the identification of suitable biomarkers for targeted treatment. Here, we review the approaches used in cutaneous melanomas and other cancers to isolate single cells and profile them at the transcriptomic and/or genomic level. We discuss how these approaches might enhance our current approach to UM management and review the emerging data from single-cell analyses in UM.

CD8 Positive T Lymphocyte Infiltration of Liver Metastases of Uveal Melanoma: A Case Report

A 78-year-old Japanese man was referred for examination of multiple small nodules on his liver detected by magnetic resonance imaging (MRI). These small nodules were hyperintense on T1-weighted MRI, and were in hepatobiliary phase on gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid enhanced MRI. Five years earlier, he had undergone curative enucleation of his left eye for uveal melanoma. US-guided biopsy revealed that the liver nodules were metastases of melanoma. Pathological examination also showed infiltration of CD8 positive T lymphocytes. The metastatic nodules remained unchanged for more than 2 years and he was not further treated. This pathology and clinical course suggest that the systemic immune response of the host could suppress hepatic metastases of uveal melanoma.

A Comprehensive Prognostic and Immunological Analysis of a Six-Gene Signature Associated With Glycolysis and Immune Response in Uveal Melanoma

Uveal melanoma (UM) is a subtype of melanoma with poor prognosis. This study aimed to construct a new prognostic gene signature that can be used for survival prediction and risk stratification of UM patients. In this work, transcriptome data from the Molecular Signatures Database were used to identify the cancer hallmarks most relevant to the prognosis of UM patients. Weighted gene co-expression network, univariate least absolute contraction and selection operator (LASSO), and multivariate Cox regression analyses were used to construct the prognostic gene characteristics. Kaplan-Meier and receiver operating characteristic (ROC) curves were used to evaluate the survival predictive ability of the gene signature. The results showed that glycolysis and immune response were the main risk factors for overall survival (OS) in UM patients. Using univariate Cox regression analysis, 238 candidates related to the prognosis of UM patients were identified (p < 0.05). Using LASSO and multivariate Cox regression analyses, a six-gene signature including ARPC1B, BTBD6, GUSB, KRTCAP2, RHBDD3, and SLC39A4 was constructed. Kaplan-Meier analysis of the UM cohort in the training set showed that patients with higher risk scores had worse OS (HR = 2.61, p < 0.001). The time-dependent ROC (t-ROC) curve showed that the risk score had good predictive efficiency for UM patients in the training set (AUC > 0.9). Besides, t-ROC analysis showed that the predictive ability of risk scores was significantly higher than that of other clinicopathological characteristics. Univariate and multivariate Cox regression analyses showed that risk score was an independent risk factor for OS in UM patients. The prognostic value of risk scores was further verified in two external UM cohorts (GSE22138 and GSE84976). Two-factor survival analysis showed that UM patients with high hypoxia or immune response scores and high risk scores had the worst prognosis. Moreover, a nomogram based on the six-gene signature was established for clinical practice. In addition, risk scores were related to the immune infiltration profiles. Taken together, this study identified a new prognostic six-gene signature related to glycolysis and immune response. This six-gene signature can not only be used for survival prediction and risk stratification but also may be a potential therapeutic target for UM patients.

Role of Natural Killer Cells in Uveal Melanoma

Simple Summary

Metastatic Uveal Melanoma (MUM) is a lethal malignancy with no durable treatment available to date. A vast majority of patients with MUM present with liver metastasis. The liver harbors metastatic disease with an apparent lack of a cytotoxic T cell response. It is becoming evident that MUM is not an immunologically silent malignancy and the investigation of non-T cell anti-tumor immunity is warranted. In this review, we highlight the relevance of Natural Killer (NK) cells in the biology and treatment of MUM. Potent anti-NK cell immunosuppression employed by uveal melanoma alludes to its vulnerability to NK cell cytotoxicity. On the contrary, micro-metastasis in the liver survive for several years within close vicinity of a plethora of circulating and liver-resident NK cells. This review provides unique perspectives into the potential role of NK cells in control or progression of uveal melanoma.

Abstract

Uveal melanoma has a high mortality rate following metastasis to the liver. Despite advances in systemic immune therapy, treatment of metastatic uveal melanoma (MUM) has failed to achieve long term durable responses. Barriers to success with immune therapy include the immune regulatory nature of uveal melanoma as well as the immune tolerant environment of the liver. To adequately harness the anti-tumor potential of the immune system, non-T cell-based approaches need to be explored. Natural Killer (NK) cells possess potent ability to target tumor cells via innate and adaptive responses. In this review, we discuss evidence that highlights the role of NK cell surveillance and targeting of uveal melanoma. We also discuss the repertoire of intra-hepatic NK cells. The human liver has a vast and diverse lymphoid population and NK cells comprise 50% of the hepatic lymphocytes. Hepatic NK cells share a common niche with uveal melanoma micro-metastasis within the liver sinusoids. It is, therefore, crucial to understand and investigate the role of intra-hepatic NK cells in the control or progression of MUM.

Comprehensive analysis of cutaneous and uveal melanoma liver metastases

BACKGROUND

The profound disparity in response to immune checkpoint blockade (ICB) by cutaneous melanoma (CM) and uveal melanoma (UM) patients is not well understood. Therefore, we characterized metastases of CM and UM from the same metastatic site (liver), in order to dissect the potential underlying mechanism in differential response on ICB.

METHODS

Tumor liver samples from CM (n=38) and UM (n=28) patients were analyzed at the genomic (whole exome sequencing), transcriptional (RNA sequencing) and protein (immunohistochemistry and GeoMx Digital Spatial Profiling) level.

RESULTS

Comparison of CM and UM metastases from the same metastatic site revealed that, although originating from the same melanocyte lineage, CM and UM differed in somatic mutation profile, copy number profile, tumor mutational burden (TMB) and consequently predicted neoantigens. A higher melanin content and higher expression of the melanoma differentiation antigen MelanA was observed in liver metastases of UM patients. No difference in B2M and human leukocyte antigen-DR (HLA-DR) expression was observed. A higher expression of programmed cell death ligand 1 (PD-L1) was found in CM compared with UM liver metastases, although the majority of CM and UM liver metastases lacked PD-L1 expression. There was no difference in the extent of immune infiltration observed between CM and UM metastases, with the exception of a higher expression of CD163 (p<0.0001) in CM liver samples. While the extent of immune infiltration was similar for CM and UM metastases, the ratio of exhausted CD8 T cells to cytotoxic T cells, to total CD8 T cells and to Th1 cells, was significantly higher in UM metastases.

CONCLUSIONS

While TMB was different between CM and UM metastases, tumor immune infiltration was similar. The greater dependency on PD-L1 as an immune checkpoint in CM and the identification of higher exhaustion ratios in UM may both serve as explanations for the difference in response to ICB. Consequently, in order to improve current treatment for metastatic UM, reversal of T cell exhaustion beyond programmed cell death 1 blockade should be considered.

Immune profiling of uveal melanoma identifies a potential signature associated with response to immunotherapy

Background

To date, no systemic therapy, including immunotherapy, exists to improve clinical outcomes in metastatic uveal melanoma (UM) patients. To understand the role of immune infiltrates in the genesis, metastasis, and response to treatment for UM, we systematically characterized immune profiles of UM primary and metastatic tumors, as well as samples from UM patients treated with immunotherapies.

Methods

Relevant immune markers (CD3, CD8, FoxP3, CD68, PD-1, and PD-L1) were analyzed by immunohistochemistry on 27 primary and 31 metastatic tumors from 47 patients with UM. Immune gene expression profiling was conducted by NanoString analysis on pre-treatment and post-treatment tumors from patients (n=6) receiving immune checkpoint blockade or 4-1BB and OX40 dual costimulation. The immune signature of UM tumors responding to immunotherapy was further characterized by Ingenuity Pathways Analysis and validated in The Cancer Genome Atlas data set.

Results

Both primary and metastatic UM tumors showed detectable infiltrating lymphocytes. Compared with primary tumors, treatment-naïve metastatic UM showed significantly higher levels of CD3+, CD8+, FoxP3+ T cells, and CD68+ macrophages. Notably, levels of PD-1+ infiltrates and PD-L1+ tumor cells were low to absent in primary and metastatic UM tumors. No metastatic organ-specific differences were seen in immune infiltrates. Our NanoString analysis revealed significant differences in a set of immune markers between responders and non-responders. A group of genes relevant to the interferon-γ signature was differentially up-expressed in the pre-treatment tumors of responders. Among these genes, suppressor of cytokine signaling 1 was identified as a marker potentially contributing to the response to immunotherapy. A panel of genes that encoded pro-inflammatory cytokines and molecules were expressed significantly higher in pre-treatment tumors of non-responders compared with responders.

Conclusion

Our study provides critical insight into immune profiles of UM primary and metastatic tumors, which suggests a baseline tumor immune signature predictive of response and resistance to immunotherapy in UM.

Prognostic significance of PD-1/PD-L1 expression in uveal melanoma: correlation with tumor-infiltrating lymphocytes and clinicopathological parameters

BACKGROUND

To understand how to improve the effect of immune checkpoint inhibitors in uveal melanoma (UM), we need a better understanding of the expression of PD-1 and PD-L1, their relation with the presence of tumor-infiltrating lymphocytes (TILs), and their prognostic relevance in UM patients.

MATERIALS AND METHODS

Expression of PD-1 and PD-L1 was assessed in 71 UM tissue samples by immunohistochemistry and quantitative real-time PCR (qRT-PCR), and further validated by western blotting. The effect of interferon gamma (IFN-γ) on PD-1/PD-L1 expression was determined on four UM cell lines.

RESULTS

Immunoreactivity of PD-1 was found in 30/71 cases and of PD-L1 in 44/71 UM samples. Tumor-infiltrating lymphocytes were found in 46% of UM tissues. PD-1 was expressed on TILs while tumor cells expressed PD-L1. UM with and without TILs showed expression of PD-1 in 69% and 18% cases, respectively (p = 0.001). Similarly, PD-L1 was found in 75% of UM with TILs and in 50% of cases without TILs, respectively (p = 0.03). DFS rate were lower in patients with TILs with expression of PD-1 and PD-L1, but the rate of DFS was higher with expression of PD-L1 in patients without TILs. After treatment of UM cell lines with IFN-γ, PD-1 expression was induced in all UM cell lines whereas PD-L1 expression was found at a lower level in untreated cells, while expression also increased following treatment with IFN-γ.

CONCLUSION

Our study suggests that increased infiltration with TILs promotes the aggressive behavior and suppresses the immune response of UM cells, thereby inhibiting immunotherapy.

Development and validation of an immune and stromal prognostic signature in uveal melanoma to guide clinical therapy

The tumor microenvironment is known to play an important role in uveal melanoma. Reliable prognostic signatures are needed to aid high risk patients and improve prognosis. Uveal melanoma tissues from three public datasets were analyzed. RNA sequence data of uveal melanoma and corresponding clinical features were obtained from The Cancer Genome Atlas database. Immune and stromal scores were calculated by applying the "ESTIMATE" algorithm. The samples were divided into high and low immune or stromal score groups. We constructed prognostic models by using the 'lasso' package and tested them for 500 iterations. The cell signature was validated in another GSE44295 and GSE84976 datasets. We found that the median survival time of the low immune/stromal score group is longer than that of the high-score group. Thirteen immune cells and one stromal cell were concerned significant in predicting poor overall survival rate. Finally, a four-cell model was identified. Further validation revealed that the low-risk group has a significantly better survival than the high-risk group in another two datasets (P < 0.05). Moreover, the high-risk group is more sensitive to immunotherapy and chemotherapy. Summarizing, the proposed immune cells signature is a promising biomarker for estimating overall survival in uveal melanoma.

Transcriptome Profiling Reveals New Insights into the Immune Microenvironment and Upregulation of Novel Biomarkers in Metastatic Uveal Melanoma

Simple Summary

Uveal melanoma (UM) is a rare aggressive eye cancer. Although treatment of the eye tumour is successful, about 50% of UM patients develop a relapse of their cancer in the liver. At present, such advanced disease is not curable. A better understanding of the metastatic UM (mUM) in the liver is essential to improve patient survival. This study examines both the response of immune cells within the liver to the UM secondaries (metastases), as well as the expression of various proteins by the UM cells. Our study demonstrates that there is a limited immune response to the mUM, but reveals that a certain type of reactive immune cell: a protumourigenic subset of macrophage is dominant within the mUM. Our research also reveals novel proteins within the mUM, which are specific to these cells and therefore may be targetable in future therapies.

Abstract

Metastatic uveal melanoma (mUM) to the liver is incurable. Transcriptome profiling of 40 formalin-fixed paraffin-embedded mUM liver resections and 6 control liver specimens was undertaken. mUMs were assessed for morphology, nuclear BAP1 (nBAP1) expression, and their tumour microenvironments (TME) using an “immunoscore” (absent/altered/high) for tumour-infiltrating lymphocytes (TILs) and macrophages (TAMs). Transcriptomes were compared between mUM and control liver; intersegmental and intratumoural analyses were also undertaken. Most mUM were epithelioid cell-type (75%), amelanotic (55%), and nBAP1-ve (70%). They had intermediate (68%) or absent (15%) immunoscores for TILs and intermediate (53%) or high (45%) immunoscores for TAMs. M2-TAMs were dominant in the mUM-TME, with upregulated expression of ANXA1, CD74, CXCR4, MIF, STAT3, PLA2G6, and TGFB1. Compared to control liver, mUM showed significant (p < 0.01) upregulation of 10 genes: DUSP4, PRAME, CD44, IRF4/MUM1, BCL2, CD146/MCAM/MUC18, IGF1R, PNMA1, MFGE8/lactadherin, and LGALS3/Galectin-3. Protein expression of DUSP4, CD44, IRF4, BCL-2, CD146, and IGF1R was validated in all mUMs, whereas protein expression of PRAME was validated in 10% cases; LGALS3 stained TAMs, and MFGEF8 highlighted bile ducts only. Intersegmental mUMs show differing transcriptomes, whereas those within a single mUM were similar. Our results show that M2-TAMs dominate mUM-TME with upregulation of genes contributing to immunosuppression. mUM significantly overexpress genes with targetable signalling pathways, and yet these may differ between intersegmental lesions.

Molecular Insights and Emerging Strategies for Treatment of Metastatic Uveal Melanoma

Uveal melanoma (UM) is the most common intraocular cancer. In recent decades, major advances have been achieved in the diagnosis and prognosis of UM allowing for tailored treatments. However, nearly 50% of patients still develop metastatic disease with survival rates of less than 1 year. There is currently no standard of adjuvant and metastatic treatment in UM, and available therapies are ineffective resulting from cutaneous melanoma protocols. Advances and novel treatment options including liver-directed therapies, immunotherapy, and targeted-therapy have been investigated in UM-dedicated clinical trials on single compounds or combinational therapies, with promising results. Therapies aimed at prolonging or targeting metastatic tumor dormancy provided encouraging results in other cancers, and need to be explored in UM. In this review, the latest progress in the diagnosis, prognosis, and treatment of UM in adjuvant and metastatic settings are discussed. In addition, novel insights into tumor genetics, biology and immunology, and the mechanisms underlying metastatic dormancy are discussed. As evident from the numerous studies discussed in this review, the increasing knowledge of this disease and the promising results from testing of novel individualized therapies could offer future perspectives for translating in clinical use.

Characterization of Uveal Melanoma Cell Lines and Primary Tumor Samples in 3D Culture

Purpose

Uveal melanoma (UM) typically spreads to the liver, where it is incurable, as there are limited therapeutic interventions available. This study aimed to standardize laboratory methods for generating three-dimensional (3D) spheroids using UM cell lines and primary UM (PUM) samples for use in drug screening.

Methods

Six UM cell lines and nine PUM, of differing genetic characteristics were cultured in two dimensions (2D) and three dimensions. 3D spheroid formation and growth were time monitored, and ImageJ software was used to calculate cross-sectional areas. PUM spheroids underwent immunohistochemistry for melanoma markers, nuclear BAP1, and cell proliferation. Chromosomal alterations in patient UM biopsies were compared with the corresponding 3D spheroid. In vitro drug assays testing doxorubicin and selumetinib assessed drug penetration and toxicity after 48 hours using imaging and the CellTiter-Glo 3D Cell Viability Assay.

Results

All six UM cell lines formed spheroids of varying sizes and compactness; six of the nine PUM samples (67%) also formed spheroids, composed of MelanA+ proliferating melanocytes and admixed macrophages. PUM spheroids were genetically identical to the original sampled tumor. In vitro drug assays showed varying penetrations into UM cell line spheroids, with doxorubicin passing into the spheroid core and selumetinib having an effect largely on peripheral cells. Both drugs caused a dose-dependent reduction in viability of 3D spheroid cells.

Conclusions

UM cell lines and PUM samples can successfully generate uniform 3D spheroids. PUM spheroids retain histological and genetic characteristics of the primary tumor. 3D spheroids are an important system for use in future high-throughput drug testing.

Translational Relevance

The use of 3D spheroids allows early-phase drug screening and is an important first step toward treatment personalization for UM patients.

Uveal melanoma pathobiology: Metastasis to the liver

Uveal melanoma (UM) is a type of intraocular tumor with a propensity to disseminate to the liver. Despite the identification of the early driver mutations during the development of the pathology, the process of UM metastasis is still not fully comprehended. A better understanding of the genetic, molecular, and environmental factors participating to its spread and metastatic outgrowth could provide additional approaches for UM treatment. In this review, we will discuss the advances made towards the understanding of the pathogenesis of metastatic UM, summarize the current and prospective treatments, and introduce some of the ongoing research in this field.

Uveal melanoma

Uveal melanoma (UM) is the most common primary intraocular malignancy in adults. UMs are usually initiated by a mutation in GNAQ or GNA11, unlike cutaneous melanomas, which usually harbour a BRAF or NRAS mutation. The annual incidence in Europe and the USA is ~6 per million population per year. Risk factors include fair skin, light-coloured eyes, congenital ocular melanocytosis, ocular melanocytoma and the BAP1-tumour predisposition syndrome. Ocular treatment aims at preserving the eye and useful vision and, if possible, preventing metastases. Enucleation has largely been superseded by various forms of radiotherapy, phototherapy and local tumour resection, often administered in combination. Ocular outcomes are best with small tumours not extending close to the optic disc and/or fovea. Almost 50% of patients develop metastatic disease, which usually involves the liver, and is usually fatal within 1 year. Although UM metastases are less responsive than cutaneous melanoma to chemotherapy or immune checkpoint inhibitors, encouraging results have been reported with partial hepatectomy for solitary metastases, with percutaneous hepatic perfusion with melphalan or with tebentafusp. Better insight into tumour immunology and metabolism may lead to new treatments.

The Role of Immune Checkpoint Blockade in Uveal Melanoma

Uveal melanoma (UM) represents the most common intraocular malignancy in adults and accounts for about 5% of all melanomas. Primary disease can be effectively controlled by several local therapy options, but UM has a high potential for metastatic spread, especially to the liver. Despite its clinical and genetic heterogeneity, therapy of metastatic UM has largely been adopted from cutaneous melanoma (CM) with discouraging results until now. The introduction of antibodies targeting CTLA-4 and PD-1 for immune checkpoint blockade (ICB) has revolutionized the field of cancer therapy and has achieved pioneering results in metastatic CM. Thus, expectations were high that patients with metastatic UM would also benefit from these new therapy options. This review provides a comprehensive and up-to-date overview on the role of ICB in UM. We give a summary of UM biology, its clinical features, and how it differs from CM. The results of several studies that have been investigating ICB in metastatic UM are presented. We discuss possible reasons for the lack of efficacy of ICB in UM compared to CM, highlight the pitfalls of ICB in this cancer entity, and explain why other immune-modulating therapies could still be an option for future UM therapies.

Immunobiology of Uveal Melanoma: State of the Art and Therapeutic Targets

Uveal Melanoma (UM) represents the most common primary intraocular malignant tumor in adults. Although it originates from melanocytes as cutaneous melanoma, it shows significant clinical and biological differences with the latter, including high resistance to immune therapy. Indeed, UM can evade immune surveillance via multiple mechanisms, such as the expression of inhibitory checkpoints (e.g., PD-L1, CD47, CD200) and the production of IDO-1 and soluble FasL, among others. More in-depth understanding of these mechanisms will suggest potential targets for the design of novel and more effective management strategies for UM patients.

Immunological Backbone of Uveal Melanoma: Is There a Rationale for Immunotherapy?

No standard treatment has been established for metastatic uveal melanoma (mUM). Immunotherapy is commonly used for this disease even though UM has not been included in phase III clinical trials with checkpoint inhibitors. Unfortunately, only a minority of patients obtain a clinical benefit with immunotherapy. The immunological features of mUM were reviewed in order to understand if immunotherapy could still play a role for this disease.

Immunotherapies for the Treatment of Uveal Melanoma-History and Future

Background: Uveal melanoma is the most common primary intraocular malignancy among adults. It is, nevertheless, a rare disease, with an incidence of approximately one case per 100,000 individuals per year in Europe. Approximately half of tumors will eventually metastasize, and the liver is the organ usually affected. No standard-of-care treatment exists for metastasized uveal melanoma. Chemotherapies or liver-directed treatments do not usually result in long-term tumor control. Immunotherapies are currently the most promising therapy option available. Methods: We reviewed both relevant recent literature on PubMed concerning the treatment of uveal melanoma with immunotherapies, and currently investigated drugs on ClinicalTrials.gov. Our own experiences with immune checkpoint blockers are included in a case series of 20 patients. Results: Because few clinical trials have been conducted for metastasized uveal melanoma, no definitive treatment strategy exists for this rare disease. The outcomes of most immunotherapies are poor, especially compared with cutaneous melanoma. However, encouraging results have been found for some very recently investigated agents such as the bispecific tebentafusp, for which a remarkably increased one-year overall survival rate, and similarly increased disease control rate, were observed in early phase studies. Conclusions: The treatment of metastatic uveal melanoma remains challenging, and almost all patients still die from the disease. Long-term responses might be achievable by means of new immunological strategies. Patients should therefore be referred to large medical centers where they can take part in controlled clinical studies.

The bidirectional crosstalk between metastatic uveal melanoma cells and hepatic stellate cells engenders an inflammatory microenvironment

Uveal melanoma is the most common primary ocular neoplasm in adults. It is peculiar for its hematogenous dissemination and its high propensity to spread to the liver. Current treatments rarely prolong patient survival. We hypothesized that metastatic uveal melanoma cells modulate the function of surrounding hepatic stellate cells to facilitate their own growth and survival. This study was conducted to investigate the role of the hepatic microenvironment on uveal melanoma aggressiveness. We demonstrated that the paracrine signaling of surrounding hepatic stellate cells have more transcriptional impact on metastatic uveal melanoma cells. Upregulated transcripts were linked to inflammation and included several interleukins. The uveal melanoma-stellate cell crosstalk induced as well the expression of transmembrane integrins. In addition, the interleukin-6 receptor inhibitor Tocilizumab did not reduce the growth of uveal melanoma cells. Our results provide evidence that inflammatory mediators are key players in the homing of uveal melanoma cells to the liver. The bidirectional crosstalk between uveal melanoma cells and hepatic stellate cells involved pro-fibrogenic interleukins. The inflammatory characteristics of the metastatic microenvironment might offer relevant therapeutic opportunities in uveal melanoma.