Macrophages in uveal melanoma and in experimental ocular tumor models: Friends or foes?

Recent Advances in Molecular and Genetic Research on Uveal Melanoma

Uveal melanoma (UM), a distinct subtype of melanoma, presents unique challenges in its clinical management due to its complex molecular landscape and tendency for liver metastasis. This review highlights recent advancements in understanding the molecular pathogenesis, genetic alterations, and immune microenvironment of UM, with a focus on pivotal genes, such as GNAQ/11, BAP1, and CYSLTR2, and delves into the distinctive genetic and chromosomal classifications of UM, emphasizing the role of mutations and chromosomal rearrangements in disease progression and metastatic risk. Novel diagnostic biomarkers, including circulating tumor cells, DNA and extracellular vesicles, are discussed, offering potential non-invasive approaches for early detection and monitoring. It also explores emerging prognostic markers and their implications for patient stratification and personalized treatment strategies. Therapeutic approaches, including histone deacetylase inhibitors, MAPK pathway inhibitors, and emerging trends and concepts like CAR T-cell therapy, are evaluated for their efficacy in UM treatment. This review identifies challenges in UM research, such as the limited treatment options for metastatic UM and the need for improved prognostic tools, and suggests future directions, including the discovery of novel therapeutic targets, immunotherapeutic strategies, and advanced drug delivery systems. The review concludes by emphasizing the importance of continued research and innovation in addressing the unique challenges of UM to improve patient outcomes and develop more effective treatment strategies.

Tumor-Associated Retinal Pigmentation in Choroidal Melanoma

PURPOSE

To report a previously unrecognized choroidal melanoma clinical feature termed tumor-associated retinal pigmentation (TARP) and determine any correlation with tumor biology.

DESIGN

Imaging and histologic analysis of a retrospective cohort of patients.

PARTICIPANTS

Patients with choroidal melanoma identified as having TARP on funduscopy at the Liverpool Ocular Oncology Centre (LOOC), United Kingdom, from January 2020 through January 2023.

METHODS

Clinical and imaging characteristics of patients diagnosed with choroidal melanoma and exhibiting TARP on fundoscopy were documented. Details of these choroidal melanomas were collated and correlated with histopathology and molecular genetic reports. The chromosome 3 status of each tumor was assessed. In enucleated samples, immunostaining was undertaken to determine the nature of the TARP using specific markers (CD68 and MelanA).

MAIN OUTCOME MEASURES

Features of TARP on widefield fundus color imaging, fundus autofluorescence (FAF), and OCT were described. Tumor chromosome 3 status and the immunoprofile of the TARP also were collated.

RESULTS

Tumor-associated retinal pigmentation had a prevalence rate of 7.47 per 100 cases of choroidal melanoma at the LOOC. Twenty-three eyes with TARP were analyzed, with a mean age of 71.4 years (range, 51-88 years). The median largest basal diameter was 16.10 mm (range, 9.17-21.32 mm), and the mean tumor thickness was 8.04 mm (range, 1.40-13.80 mm). Tumor-associated retinal pigmentation was observed on widefield color fundus imaging, with hypofluorescence on FAF images and represented hyperreflective foci located in intraretinal and subretinal spaces on OCT scans. Seventeen patients (73.9%) underwent enucleation, and 6 patients (26.1%) underwent globe-sparing treatment. Molecular genetic analysis of 20 choroidal melanomas (after enucleation or radiotherapy biopsy) revealed monosomy 3 in 18 tumors (90%). Immunostaining of the TARP in enucleated eyes showed CD68+ melanophages in all 17 patients appearing as scattered cells and aggregates; MelanA findings were negative.

CONCLUSIONS

Tumor-associated retinal pigmentation represents tumor-associated macrophages, not melanocytes, within intraretinal and subretinal spaces of larger choroidal melanomas. Radiation treatments need not involve this area in the treatment plan, minimizing radiation-related complications. This novel clinical sign seems to be linked to tumors of high metastatic-risk clinical and genetic characteristics, with a preponderance having monosomy 3 anomalies.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Prognostic analysis of uveal melanoma based on the characteristic genes of M2-type macrophages in the tumor microenvironment

Uveal melanoma arises from stromal melanocytes and is the most prevalent primary intraocular tumor in adults. It poses a significant diagnostic and therapeutic challenge due to its high malignancy and early onset of metastases. In recent years, there has been a growing interest in the role of diverse immune cells in tumor cell development and metastasis. Using The Cancer Genome Atlas and the gene expression omnibus databases, and the CIBERSORT method, we investigated the topography of intra-tumor immune infiltration in uveal melanoma in this research. We evaluated the prognosis of uveal melanoma patients using the M2 macrophage immune cell infiltration score in conjunction with clinical tumor patient data. We built a prognostic model based on the distinctive genes of M2 macrophages and combined it with patients' clinical data in the database; we ran a survival prognostic analysis to authenticate the model's accuracy. The functional study revealed the importance of macrophage-associated genes in the development of uveal melanoma. Moreover, the reliability of our prediction model was verified by combining tumor mutational load, immune checkpoint, and drug sensitivity, respectively. Our study provides a reference for the follow-up study of uveal melanoma.

Multifunctional Nanoparticles Precisely Reprogram the Tumor Microenvironment and Potentiate Antitumor Immunotherapy after Near-Infrared-II Light-Mediated Photothermal Therapy

Mild-temperature photothermal therapy (mild PTT) is a safe and efficient antitumor therapy. However, mild PTT alone usually fails to activate the immune response and prevent tumor metastasis. Herein, a photothermal agent, copper sulfide@ovalbumin (CuS@OVA), with an effective PTT effect in the second near-infrared (NIR-II) window, is developed. CuS@OVA can optimize the tumor microenvironment (TME) and evoke an adaptive immune response. Copper ions are released in the acidic TME to promote the M1 polarization of tumor-associated macrophages. The model antigen OVA not only acts as a scaffold for nanoparticle growth but also promotes the maturation of dendritic cells, which primes naive T cells to stimulate adaptive immunity. CuS@OVA augments the antitumor efficiency of the immune checkpoint blockade (ICB) in vivo, which suppresses tumor growth and metastasis in a mouse melanoma model. The proposed therapeutic platform, CuS@OVA nanoparticles, may be a potential adjuvant for optimizing the TME and improving the efficiency of ICB as well as other antitumor immunotherapies. STATEMENT OF SIGNIFICANCE: Mild-temperature photothermal therapy (mild PTT) is a safe and efficient antitumor therapy, but usually fails to activate the immune response and prevent tumor metastasis. Herein, we develop a photothermal agent, copper sulfide@ovalbumin (CuS@OVA), with an excellent PTT effect in the second near-infrared (NIR-II) window. CuS@OVA can optimize the tumor microenvironment (TME) and evoke an adaptive immune response by promoting the M1 polarization of tumor-associated macrophages and the maturation of dendritic cells. CuS@OVA augments the antitumor efficiency of the immune checkpoint blockade (ICB) in vivo, suppressing tumor growth and metastasis. The platform may be a potential adjuvant for optimizing the TME and improving the efficiency of ICB as well as other antitumor immunotherapies.

PRRX1 Is a Novel Prognostic Biomarker and Facilitates Tumor Progression Through Epithelial–Mesenchymal Transition in Uveal Melanoma

Uveal melanoma (UM) is the most common primary intraocular malignancy in adults. UM develops and is sustained by inflammation and immunosuppression from the tumor microenvironment (TME). This study sought to identify a reliable TME-related biomarker that could provide survival prediction and new insight into therapy for UM patients. Based on clinical characteristics and the RNA-seq transcriptome data of 80 samples from The Cancer Genome Atlas (TCGA) database, PRRX1 as a TME- and prognosis-related gene was identified using the ESTIMATE algorithm and the LASSO–Cox regression model. A prognostic model based on PRRX1 was constructed and validated with a Gene Expression Omnibus (GEO) dataset of 63 samples. High PRRX1 expression was associated with poorer overall survival (OS) and metastasis-free survival (MFS) in UM patients. Comprehensive results of the prognostic analysis showed that PRRX1 was an independent and reliable predictor of UM. Then the results of immunological characteristics demonstrated that higher expression of PRRX1 was accompanied by higher expression of immune checkpoint genes, lower tumor mutation burden (TMB), and greater tumor cell infiltration into the TME. Gene set enrichment analysis (GSEA) showed that high PRRX1 expression correlated with angiogenesis, epithelial–mesenchymal transition (EMT), and inflammation. Furthermore, downregulation of PRRX1 weakened the process of EMT, reduced cell invasion and migration of human UM cell line MuM-2B in vitro. Taken together, these findings indicated that increased PRRX1 expression is independently a prognostic factor of poorer OS and MFS in patients with UM, and that PRRX1 promotes malignant progression of UM by facilitating EMT, suggesting that PRRX1 may be a potential target for UM therapy.

Necrotic Uveal Melanoma Mimics Orbital Cellulitis: A Review

Background

Uveal melanoma is the most common primary intraocular malignancy in adults, often resulting in painless vision loss. We report a case of necrotic uveal melanoma presenting with orbital inflammation mimicking orbital cellulitis and present a comprehensive review of the literature and tabulation of reported cases.

Summary

Our review found 44 published reports of spontaneously necrotic uveal melanoma involving 55 patients. Of these reports, 26 patients (47%) presented with orbital cellulitis. Presenting symptoms of necrotic uveal melanoma with orbital cellulitis included proptosis (82.8%), pain (80.7%), vision loss (61.5%), and restricted extraocular movements (46.2%).

Key Messages

Uveal melanoma can rarely mimic orbital cellulitis. Autoinfarction and tumor necrosis causes secondary orbital inflammation. Intraocular malignancy must remain in the differential for patients with orbital inflammation and vision loss.

Blocking iASPP/Nrf2/M-CSF axis improves anti-cancer effect of chemotherapy-induced senescence by attenuating M2 polarization

The complex interaction between cancer cells and the immune microenvironment is a central regulator of tumor growth and the treatment response. Chemotherapy-induced senescence is accompanied by the senescence-associated secretion phenotype (SASP). However, the mechanisms underlying the regulation of the SASP remain the most poorly understood element of senescence. Here, we show that nuclear erythroid factor 2-like factor 2 (Nrf2), a master antioxidative transcription factor, accumulates upon doxorubicin-induced senescence. This is due to the increased cytoplasmic Inhibitor of Apoptosis Stimulating Protein of P53, iASPP, which binds with Keap1, interrupting Keap1/Nrf2 interaction and promoting Nrf2 stabilization and activation. Activated Nrf2 transactivates a novel target gene of SASP factor, macrophage colony-stimulating factor (M-CSF), which subsequently acts on macrophages and induces polarization from M1 to M2 via a paracrine mechanism. Genetic inhibition of iASPP-Nrf2 suppresses the growth of apoptosis-resistant xenografts, with further analysis revealing that M-CSF/M-CSFR-regulated macrophage polarization is critical for the functional outcomes delineated above. Overall, our data uncover a novel function of iASPP-Nrf2 in skewing the immune microenvironment under treatment-induced senescence. Targeting the iASPP-Nrf2 axis could be a powerful strategy for the implementation of new chemotherapy-based therapeutic opportunities.

Regulation of epigenetic homeostasis in uveal melanoma and retinoblastoma

Uveal melanoma (UM) and retinoblastoma (RB), which cause blindness and even death, are the most frequently observed primary intraocular malignancies in adults and children, respectively. Epigenetic studies have shown that changes in the epigenome contribute to the rapid progression of both UM and RB following classic genetic changes. The loss of epigenetic homeostasis plays an important role in oncogenesis by disrupting the normal patterns of gene expression. The targetable nature of epigenetic modifications provides a unique opportunity to optimize treatment paradigms and establish new therapeutic options for both UM and RB with these aberrant epigenetic modifications. We aimed to review the research findings regarding relevant epigenetic changes in UM and RB. Herein, we 1) summarize the literature, with an emphasis on epigenetic alterations, including DNA methylation, histone modifications, RNA modifications, noncoding RNAs and an abnormal chromosomal architecture; 2) elaborate on the regulatory role of epigenetic modifications in biological processes during tumorigenesis; and 3) propose promising therapeutic candidates for epigenetic targets and update the list of epigenetic drugs for the treatment of UM and RB. In summary, we endeavour to depict the epigenetic landscape of primary intraocular malignancy tumorigenesis and provide potential epigenetic targets in the treatment of these tumours.

Eye Diseases Direct Interest to Complement Pathway and Macrophages as Regulators of Inflammation in COVID-19

ABSTRACT

Many of the risk factors for developing severe coronavirus disease 2019 (COVID-19) are also risk factors for eye diseases such as age-related macular degeneration (AMD). During the past decades, macrophages and the complement pathway (as a part of the innate immune system) have been identified as important contributors to the development of AMD, and we suggest that these mechanisms are of similar importance for the clinical course of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. Based on the experience with AMD, we discuss how behavioral factors such as diet, smoking and higher body mass index, as well as genetic determinants such as the complement and immune pathway genes may lead to the overactive inflammatory phenotypes seen in some patients with COVID-19, and may in part explain the heterogeneity of disease manifestations and outcomes. Based on this experience, we discuss potential genetic research projects and elaborate on preventive and treatment approaches related to COVID-19.

Implications of macrophage polarization in corneal transplantation rejection

Corneal transplantation rejection remains an urgent problem threatening the success rate of high-risk patients. Macrophages are involved in the rejection of corneal transplants. Macrophages have M1 and M2 phenotypes, classified according their response to external stimuli. Macrophage polarization, through which these distinct forms are activated, is not only involved in the occurrence and development of inflammation, tumors, and autoimmune and other diseases, but also participates in graft rejection. This study provides an overview of the types of macrophages and mechanisms of their polarization, and review current knowledge regarding their involvement in corneal transplantation and potential therapeutic applications. Consideration of the relationship between the direction of macrophage polarization and the determination of graft survival and how it can be modified, is important for the development of novel corneal anti-rejection therapies.

Antitumor Efficacy of Oncolytic Herpes Virus Type 1 Armed with GM-CSF in Murine Uveal Melanoma Xenografts

Background

Uveal melanoma (UM) is the most common primary intraocular tumor in adults with a high incidence of metastasis. Standard care therapies for UM include enucleation and radiation, which are minimally effective in prolonging patient survival. Oncolytic virus treatment has become a new trend in cancer field. Of which, oncolytic herpes simplex virus type 1 (HSV-1) therapy is one of the most effective antitumor treatments. Here, we established an oncolytic HSV-1 encoding granulocyte-macrophage colony-stimulating factor (GM-CSF), tested its efficacy in UM therapy, and investigated the innate immune response induced by this virus.

Methods

Oncolytic HSV-1 expressing GM-CSF (HSV-GM-CSF) was constructed, then verified using qPCR and Western blot assays. Cell viability assays and transmission electron microscopy were conducted on three UM cell lines, MUM2B, 92.1, and MP41, to assess the cell-killing ability and virus infection of this virus. For in vivo experiments, BALB/c-nude mice in situ UM xenografts were established to testify the efficacy of the oncolytic virus, oncolytic HSV-1, and HSV-GM-CSF groups, respectively. IVIS images, ocular volumes, mice weights, and survivals were tracked to see the efficacy of the virus. Hematoxylin and eosin staining, immunohistochemistry, and flow cytometry analyses were conducted to demonstrate the immune activity after virus treatment.

Results

All three tested UM cell lines were sensitive to infection by HSV-GM-CSF. In vivo xenograft experiments revealed that oncolytic virus HSV-1 reduced UM tumor volume and that oncolytic virus HSV-1 armed with GM-CSF enhanced the antitumor effect compared with unmodified HSV-1. The bodyweights of untreated control group mice were significantly lower than those of mice in either virus-treated group (HSV-1 or HSV-GM-CSF). Follow-up survivals were prolonged in the virus-treated groups compared with the control group and were prolonged to a greater extent in the HSV-GM-CSF group than in the HSV-1 group. Macrophage stimulation was observed following HSV-GM-CSF treatment.

Conclusion

Our results indicate that the recombinant oncolytic virus HSV-GM-CSF is a potential therapeutic treatment for UM.

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.

Constitutive expression of c-REL in uveal melanoma patients: correlation with clinicopathological parameters and patient outcome

PURPOSE

Uveal melanoma (UM) is the most common intraocular cancer with a high mortality rate that requires new research in the field of prevention and treatment. c-REL is a member of the nuclear factor κB (NF-κB) transcription factor family and an emerging regulator of tumorigenesis. Therefore, the objective of the study is to evaluate the constitutive expression of c-REL in uveal melanoma patients and its prognostic significance.

METHODS

Detection of c-REL expression was carried out by immunohistochemistry in all 75 patients, and qRT-PCR performed on 58 fresh cases of uveal melanoma along with IL-6 status. Immunoblot was performed to validate immunohistochemistry results. Expression of c-REL protein correlated with clinicopathological parameters and overall survival of patients.

RESULTS

Immunohistochemistry results revealed nuclear expression of the c-REL protein (56%) in our cases. Out of 75 cases, 31 cases showed nuclear expression, and 11 cases had cytoplasmic expression. qRT-PCR showed upregulation of the REL gene in 56.89% cases at the transcriptional level. There was a statistically significant difference in the overall survival of patients with c-REL nuclear immunopositivity (p = 0.0048). On multivariate analysis, scleral invasion and c-REL nuclear expression found to be an independent prognostic factor (p < 0.05) CONCLUSIONS: To the best of our knowledge, this was the first study reporting the expression of the c-REL protein in uveal melanoma. Strong nuclear immunoexpression of c-Rel suggests NFκB pathway activation which might be involved in the progression of the disease. Differential expression of c-REL protein may be used as an attractive target for the development of anticancer strategies.

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.

SARI prevents ocular angiogenesis and inflammation in mice

SARI (Suppressor of AP‐1, regulated by IFN‐β) is known to play an important role in some systemic disease processes such an inflammatory conditions and cancer. We hypothesize that SARI may also play a role in ocular diseases involving inflammation and neovascularization. To explore our hypothesis, further, we investigated an endotoxin‐induced uveitis (EIU) and experimental argon laser‐induced choroidal neovascularization (CNV) model in SARI wild‐type (SARI^WT) and SARI‐deficient (SARI^−/−) mice. Through imaging, morphological and immunohistochemical (IHC) studies, we found that SARI deficiency exacerbated the growth of CNV. More VEGF‐positive cells were presented in the retina of SARI^−/− mice with CNV. Compared to SARI^WT mice, more inflammatory cells infiltrated the ocular anterior segment and posterior segments in SARI^−/− mice with EIU. Collectively, the results point to a potential dual functional role of SARI in inflammatory ocular diseases, suggesting that SARI could be a potential therapy target for ocular inflammation and neovascularization.

Uveal melanoma: Towards a molecular understanding

Uveal melanoma is an aggressive malignancy that originates from melanocytes in the eye. Even if the primary tumor has been successfully treated with radiation or surgery, up to half of all UM patients will eventually develop metastatic disease. Despite the common origin from neural crest-derived cells, uveal and cutaneous melanoma have few overlapping genetic signatures and uveal melanoma has been shown to have a lower mutational burden. As a consequence, many therapies that have proven effective in cutaneous melanoma -such as immunotherapy- have little or no success in uveal melanoma. Several independent studies have recently identified the underlying genetic aberrancies in uveal melanoma, which allow improved tumor classification and prognostication of metastatic disease. In most cases, activating mutations in the Gα11/Q pathway drive uveal melanoma oncogenesis, whereas mutations in the BAP1, SF3B1 or EIF1AX genes predict progression towards metastasis. Intriguingly, the composition of chromosomal anomalies of chromosome 3, 6 and 8, shown to correlate with an adverse outcome, are distinctive in the BAP1^mut, SF3B1^mut and EIF1AX^mut uveal melanoma subtypes. Expression profiling and epigenetic studies underline this subdivision in high-, intermediate-, or low-metastatic risk subgroups and suggest a different approach in the future towards prevention and/or treatment based on the specific mutation present in the tumor of the patients. In this review we discuss the current knowledge of the underlying genetic events that lead to uveal melanoma, their implication for the disease course and prognosis, as well as the therapeutic possibilities that arise from targeting these different aberrant pathways.

Necrotic uveal melanoma presenting as orbital cellulitis with intraocular hemorrhage: A case report

Purpose

To report a case of necrotic uveal melanoma presenting as orbital cellulitis with an intraocular hemorrhage.

Observations

A 61 year-old non-verbal male presented with a two-week history of right eyelid swelling and erythema unresponsive to antibiotics. In addition to these signs of orbital cellulitis, he presented with an opaque media precluding fundus visualization. He was later found to have a collar-button shaped mass consistent with uveal melanoma on B scan ultrasonography during an exam under anesthesia. The patient underwent enucleation with histopathology confirming a necrotic uveal melanoma.

Conclusion and Importance

This case demonstrates how necrotic uveal melanoma can present as orbital cellulitis and the importance of keeping the diagnosis on the differential.

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.

Natural killer cells and pigment epithelial-derived factor control the infiltrative and nodular growth of hepatic metastases in an Orthotopic murine model of ocular melanoma

Background

Metastases account for 90% of all cancer-related deaths, becoming a therapeutic problem. Approximately 50% of all uveal melanoma (UM) patients will develop metastases, mainly in the liver. Post-mortem analyses of livers from metastatic UM patients showed two different metastatic growth patterns: infiltrative and nodular. The infiltrative pattern exhibits tumor infiltration directly to the hepatic lobule and minimal angiogenesis. The nodular pattern shows clusters of tumor cells around the portal venules that efface the liver parenchyma. We recently demonstrated Natural Killer (NK) cells play a pivotal role in the control of hepatic metastases and the pigment epithelial-derived factor (PEDF) controls angiogenesis in the liver using our established ocular melanoma animal model. In this study we investigated the role of NK cells and PEDF in the development of metastatic growth patterns, as this can contribute to the development of novel therapeutics specific towards each growth pattern.

Methods

We utilize our established ocular melanoma animal model by inoculation of B16-LS9 melanoma cells into C57BL/6 J mice (WT), anti-asialo GM1-treated C57BL/6 J mice (NK-depleted), and PEDF^−/− C57BL/6 J mice. Three weeks after inoculation we evaluated the metastatic growth patterns and stratified them based of the numbers of tumor cells. To evaluate angiogenesis the mean vascular density (MVD) was calculated. The immune compartment of the liver was analyzed by flow cytometry.

Results

Our in vivo work showed two distinct metastatic growth patterns, the infiltrative and nodular, recapitulating the post-mortem analyses on human liver tissue. We discovered NK cells control the infiltrative growth. In contrast, PEDF controlled anti-angiogenic responses, showing higher MVD values compared to NK-depleted and WT animals. The myeloid lineage, comprised of monocytes, macrophages, and myeloid-derived suppressor cells, was reduced in the absence of NK cells or PEDF.

Conclusions

Our animal model recapitulates the metastatic growth patterns observed in the human disease. We demonstrated a role for NK cells in the development of the infiltrative growth pattern, and a role for PEDF in the development of the nodular pattern. The understanding of the complexity associated with the metastatic progression has profound clinical implications in the diagnostic and disease-management as we can develop and direct more effective therapies.

Identification of canonical NFκB (C-NFκB) pathway in uveal melanoma and their relation with patient outcome

Inflammation in uveal melanoma (UM) is linked to a bad prognosis. It is rare type of cancer, of which the metastases are usually fatal within a year. Infiltration with an inflammatory infiltrate increases with disease progression but does not seem to inhibit metastasis. The Canonical NFκB (C-NFκB) pathway is known to play a crucial role in tumor inflammation. We therefore, studied the expression of canonical NFκB proteins and their prognostic relevance in UM. Our study evaluated the expression of C-NFκB proteins (p65, p50, and c-Rel) by using immunohistochemistry on sections from 75 formalin-fixed UM. Activation of the NFκB subunit was determined on fresh tumor specimens by measuring the DNA-binding activity in nuclei using an NFκB ELISA assay. Real-time PCR was performed on frozen material on 58 tumors. The presence of native C-NFκB heterodimers (p65/p50 and c-Rel/p50) was confirmed by co-immunoprecipitation followed by Western blotting. We observed a high nuclear immunoreactivity of p65, p50, and c-Rel proteins in 54, 60 and 41% UM cases, respectively. Expression of C-NFκB proteins significantly correlated with parameters which are related to the inflammatory environment of UM. Nuclear immunoreactivity of p65 and p50 was associated with lower patient survival (p = 0.041; p = 0.048) while c-Rel was not. Our finding reveals that C-NFκB proteins expressed are more often in UM with inflammation than those without inflammation. Activation of the canonical NFκB pathway is more frequent in high risk UM patients. These observations might help to understand the behaviour of high risk tumors, with upregulation of C-NFκB proteins contributing to tumor aggressiveness.

Cytokines concentrations in aqueous humor of eyes with uveal melanoma

Uveal melanoma (UM) is the major intraocular malignancy in adults, of which the molecular biology is still unknown. Therefore, this study was designed to determine the aqueous concentrations of angiogenic, inflammatory, and chemotactic cytokines in eyes with UM.Aqueous humor samples were collected from 38 patients with UM and 22 patients undergoing cataract surgery. Interleukin 6, 8 (IL-6, IL-8, respectively), interferon-inducible protein-10 (IP-10), placental growth factor1 (PIGF1), regulated on activation, normal T Cell expressed and secreted (RANTES), monocyte chemoattractant protein-1 (MCP-1), nerve growth factor-beta (NGF-β), epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), and vascular endothelia growth factor A (VEGF-A) were assessed by multiplex bead assay.In the study group, significantly higher concentrations of IL-6 (P = .006), IL-8 (P = .018), IP-10 (P = .004), RANTES (P = .008), MCP-1 (P = .02), NGF-β (P = .013), EGF (P < .001), PIGF1 (P = .01), bFGF (P = .016), and VEGF (P = .017) were measured, when compared with the control group.Several angiogenic, inflammatory, and chemotactic cytokines are highly expressed in the aqueous humor of the UM eyes, which provides new insights into the pathophysiology of UM and could be potential targets for treatment.

Does NEMO/IKKγ protein have a role in determining prognostic significance in uveal melanoma?

PURPOSE

Uveal melanoma, although a rare form of cancer, is the most common primary malignancy of the eye in adults. Nuclear factor-κB (NF-κB) is a transcription factor that transactivates genes involved in the regulation of cell growth, apoptosis, angiogenesis, and metastasis, but the molecular mechanisms that negatively regulate NF-κB activation are not fully understood. NF-κB can also be activated by DNA damage pathway through NEMO protein. Therefore, the objective of this study is to elucidate the role of NEMO/IKKγ protein in uveal melanoma patients.

METHODS

Seventy-five formalin-fixed paraffin-embedded prospective tissues of uveal melanoma were included in the present study. These cases were reviewed and investigated for the expression of NEMO/IKKγ protein by immunohistochemistry and validated by western blotting along with the qRT-PCR for mRNA expression. Expression levels were correlated with the clinicopathological parameters and patients' outcome.

RESULTS

Immunohistochemistry showed cytoplasmic expression of NEMO/IKKγ expression in only 22 out of 75 (29.33%) cases. This result was confirmed by western blotting, and correlated well with the immunohistochemical expression of NEMO/IKKγ protein (48 kDa). In addition, downregulation of this gene was found in 87.93% of the cases when compared with the normal tissues. On statistical analysis, loss of NEMO/IKKγ protein was correlated with neovascularization, high mitotic count, and presence of vascular loop (p < 0.05). There was less overall survival rate with low expression of NEMO/IKKγ protein in patients with uveal melanoma.

CONCLUSION

This was the first study suggesting the relevant role of NEMO/IKKγ protein, and highlights the prognostic significance with outcome in uveal melanoma patients. This protein might be used as a screening biomarker in these patients after large-scale validation and translational studies.

Macrophages in skin melanoma-the key element in melanomagenesis

Cutaneous melanoma is an aggressive cancer and its onset and growth are associated, through direct and indirect interactions, with the cancer microenvironment. The microenvironment comprises a dynamic complex of numerous types of cells (due to histogenesis) that constantly interact with each other through multiple cytokines and signaling proteins. Macrophages are one of the most thoroughly studied pleiotropic cells of the immune system. One of their major cytophysiological functions is their involvement in phagocytosis. Previous studies examining the microenvironment of melanomas and tumor-associated macrophages have revealed that they are involved in all stages of melanomagenesis. In the case of cancer initiation, they form an inflammatory microenvironment and then suppress the anticancer activity of the immune system, stimulate angiogenesis, enhance migration and invasion of the cancer cells, and ultimately contribute to the metastatic process. The present review provides a detailed overview on the function of macrophages in the melanoma microenvironment.

Monocyte chemoattractant protein 1 and fractalkine play opposite roles in angiogenesis via recruitment of different macrophage subtypes

AIM

To explore the interaction between macrophages and chemokines [monocyte chemoattractant protein 1 (MCP-1/CCL2) and fractalkine/CX3CL1] and the effects of their interaction on neovascularization.

METHODS

Human peripheral blood mononuclear cells, donated by healthy volunteers, were separated and cultured in RPMI-1640 medium containing 10% fetal bovine serum, then induced into macrophages by stimulation with 30 µg/L granulocyte macrophage-colony stimulating factor (GM-CSF). The expression of CCR2 and/or CX3CR1 in the macrophages was examined using flow cytometry. Macrophages were then stimulated with recombinant human CCL2 (rh-CCL2) or recombinant human CX3CL1 (rh-CX3CL1). The expression of angiogenesis-related genes, including VEGF-A, THBS-1 and ADAMTS-1 were examined using real-time quantitative polymerase chain reaction (PCR). Supernatants from stimulated macrophages were used in an assay of human retinal endothelial cell (HREC) proliferation. Finally, stimulated macrophages were co-cultured with HREC in a migration assay.

RESULTS

The expression rate of CCR2 in macrophages stimulated by GM-CSF was 42%±1.9%. The expression rate of CX3CR1 was 71%±3.3%. Compared with vehicle-treated groups, gene expression of VEGF-A in the macrophages was greater in 150 mg/L CCL2-treated groups (P<0.05), while expression of THBS-1 and ADAMTS-1 was significantly lower (P<0.05). By contrast, compared with vehicle-treated groups, expression of VEGF-A in 150 mg/L CX3CL1-treated groups was significantly lower (P<0.05), while expression of THBS-1 and ADAMTS-1 was greater (P<0.05). Supernatants from CCL2 treated macrophages promoted proliferation of HREC (P<0.05), while supernatants from CX3CL1-treated macrophages inhibited the proliferation of HREC (P<0.05). HREC migration increased when co-cultured with CCL2-treated macrophages, but decreased with CX3CL1-treated macrophages (P<0.05).

CONCLUSION

CCL2 and CX3CL1 exert different effects in regulation of macrophage in expression of angiogenesis-related factors, including VEGF-A, THBS-1 and ADAMTS-1. Our findings suggest that CCL2 and CX3CL1 may be candidate proteins for further exploration of novel targets for treatment of ocular neovascularization.

Coexisting Phacoanaphylaxis and Choroidal Melanoma: An Unusual Intraocular Inflammation

PURPOSE

To describe an unusual case of panuveitis in coexisting choroidal melanoma and phacoanaphylaxis.

METHODS

Clinical records of the patient with intraocular melanoma and pathologic findings of the affected eye were reviewed. Composition of inflammatory infiltrates involving the tumor and lens was evaluated immunohistochemically.

RESULTS

Histologically, tumor showed a choroidal mixed cell type malignant melanoma with infiltration of inflammatory cells. The globe also showed typical features of phacoanaphylaxis, characterized by disruptions of the lens capsule with zonal granulomatous inflammation. The inflammatory infiltration revealed the predominant presence of both cytotoxic T cells and histiocytes in phacoanaphylaxis and intra-tumoral inflammation.

CONCLUSIONS

The current clinico-pathologic case report suggests that a long standing intraocular melanoma can present with phacoanaphylaxis. The immunophenotype of the inflammatory infiltrates at both sites, lens and the tumor, is similar, cytotoxic T cells and histiocytes, favoring a common immune inflammatory process directed at the tumor and the lens.

Immunotherapy for the Treatment of Uveal Melanoma: Current Status and Emerging Therapies

PURPOSE OF REVIEW

Uveal melanoma is a distinct subset of melanoma with a biology and treatment approach that is unique from that of cutaneous melanoma. Here we will review the current data evaluating immunotherapies in both the adjuvant and metastatic settings in uveal melanoma.

RECENT FINDINGS

In the adjuvant setting, interferon demonstrated no survival benefit in uveal melanoma, and studies evaluating immune-based strategies such as vaccine therapy are ongoing. Anti-CTLA-4 and anti-PD-1/ PD-L1 blockade in uveal melanoma have been evaluated in several small prospective and/or retrospective studies with rare responses and no overall survival benefit demonstrated. Ongoing studies evaluating combination checkpoint inhibition and other antibody-based therapies are ongoing. Although immunotherapy with anti-CTLA-4 and anti-PD-1 agents has dramatically changed the treatment approach to cutaneous melanoma, its success in uveal melanoma has been much more limited. Clinical trial participation should be prioritized in patients with uveal melanoma.

Macrophage polarization in experimental and clinical choroidal neovascularization

Macrophages play an important role in the development of age-related macular degeneration (AMD). In this study, the spatial and temporal changes and the polarization of macrophages in murine laser-induced choroidal neovascularization (CNV) were investigated, and the polarized M1 and M2 biomarkers in the aqueous humors of neovascular AMD (nAMD) patients were studied. Macrophages, the main infiltrating inflammatory cells in CNV lesions, were evidenced by a significant increase in F4/80 mRNA expression and by the infiltration of F4/80+ cells in the lesions and the vicinity of laser-induced CNV. The mRNA expressions of M1-related markers were dramatically upregulated in the early stage, while the M2-related markers were slightly upregulated in the middle stage and sustained until the late stage. The results of immunostaining showed a similar early-but-transient M1 pattern and a delayed-but-sustained M2 pattern in laser-induced CNV. In addition, a higher M2/M1 ratio was found in both the murine models (Arg-1/iNOS and CCL22/CXCL10) and the aqueous humors of nAMD patients (CCL22/CXCL10) than in the controls. Our results suggested that the dynamic patterns of M1 and M2 were different in both the experimental and clinical CNV. The M2 macrophages were predominant and may play a more important role in the development of CNV.

Impact of macrophages on tumor growth characteristics in a murine ocular tumor model

Tumor associated macrophages (TAM), mean vascular density (MVD), PAS positive extravascular matrix patterns, and advanced patients' age are associated with a poor prognosis in uveal melanoma. These correlations may be influenced by M2 macrophages and their cytokine expression pattern. Thus, the effect of TAM and their characteristic cytokines on histologic tumor growth characteristics were studied under the influence of age. Ninety five CX3CR1(+/GFP) mice (young 8-12weeks, old 10-12months) received an intravitreal injection of 1 × 10(5) HCmel12 melanoma cells. Subgroups were either systemically macrophage-depleted by Clodronate liposomes (n = 23) or received melanoma cells, which were pre-incubated with the supernatant of M1- or M2-polarized macrophages (n = 26). Eyes were processed histologically/immunohistochemically (n = 75), or for flow cytometry (n = 20) to analyze tumor size, mean vascular density (MVD), extravascular matrix patterns, extracellular matrix (ECM) and the presence/polarization of TAM. Prognostically significant extravascular matrix patterns (parallels with cross-linkings, loops, networks) were found more frequently in tumors of untreated old compared to tumors of untreated young mice (p = 0.024); as well as in tumors of untreated mice compared to tumors of macrophage-depleted mice (p = 0.014). Independent from age, M2-conditioned tumors showed more TAM (p = 0.001), increased collagen IV levels (p = 0.024) and a higher MVD (p = 0.02) than M1-conditioned tumors. Flow cytometry revealed a larger proportion of M2-macrophages in old than in young mice. The results indicate that TAM and their cytokines appear to be responsible for a more aggressive tumor phenotype. Tumor favoring and pro-angiogenic effects can be directly attributed to a M2-dominated tumor microenvironment rather than to age-dependent factors alone. However, an aged immunoprofile with an increased number of M2-macrophages may provide a tumor-favoring basis. Further, old mice represent a more suitable tumor model instead of young mice since their histologic tumor pattern better resembles human tumors.

Uveal melanoma as a target for immune-therapy

Uveal melanoma (UM) is a rare disease that can be deadly in spite of adequate local treatment. Systemic therapy with chemotherapy is usually ineffective and new-targeted therapies have not improved results considerably. The eye creates an immunosuppressive environment in order to protect eyesight. UM cells use similar processes to escape immune surveillance. Regarding innate immunity the production of macrophage inhibiting factor (MIF) and TGF-β, added to MHC class I upregulation, inhibits the action of natural killer (NK) cells. UM cells produce cytokines such as IL-6 and IL-10 that favor macrophage differentiation to the M2 subtype, which promote tumor growth instead of an effective immune response. UM cells also impair the adaptive immune response through production of indoleamine 2,3-dioxygenase (IDO), overexpression of programmed death ligand-1 (PD-L1), alteration of FasL expression, and resistance to perforin. This biological background suggests that immunotherapy could be effective in fighting UM. A Phase II clinical trial with Ipilimumab has shown promising results with mean Overall Survival rate of ten months, and close to 50% of the patients alive at one year. Clinical trials with anti-PD1 antibodies in monotherapy and in combination with anti-CTLA4 are currently recruiting patients worldwide.

Efficacy and vitreous levels of topical NSAIDs

INTRODUCTION

Nonsteroidal anti-inflammatory drugs (NSAIDs) are one of the most commonly prescribed medications and are routinely used for their analgesic, antipyretic, and anti-inflammatory properties. Because of their potent cyclooxygenase-inhibitory activity, they can inhibit pro-inflammatory prostaglandin synthesis, leading to complex inflammatory cascades. NSAIDs have been broadly used systemically for many decades and have recently become commercially available in the form of topical ophthalmic formulations. NSAIDs are weak acids with pKa values mostly between 3.5 and 4.5 and are poorly water-soluble. New, aqueous ophthalmic solutions of NSAIDs that afford better tissue penetration have recently been developed. In ophthalmological practice, topical NSAIDs are mostly used to stabilize pupillary dilation during intraocular surgery, manage postoperative pain and inflammation, and treat pseudophakic cystoid macular edema.

AREAS COVERED

This review focuses on the vitreous penetration of topical NSAIDs and their potential clinical applications in the treatment of retinal diseases.

EXPERT OPINION

A growing body of evidence suggests that NSAIDs may be beneficial in the treatment of age-related macular degeneration, diabetic retinopathy, and ocular tumors. Recent studies from our group and other authors have shown that the vitreous levels of NSAID exceed the median inhibitory concentration, which can significantly decrease vitreous PGE2 levels.

Differences in the distribution, phenotype and gene expression of subretinal microglia/macrophages in C57BL/6N (Crb1 rd8/rd8) versus C57BL6/J (Crb1 wt/wt) mice

Background

Microglia/macrophages (MG/MΦ) are found in the subretinal space in both mice and humans. Our goal was to study the spatial and temporal distribution, the phenotype, and gene expression of subretinal MG/MΦ in mice with normal retinas and compare them to mice with known retinal pathology.

Methods

We studied C57BL/6 mice with (C57BL/6N), or without (C57BL/6J) the rd8 mutation in the Crb1 gene (which, in the presence of yet unidentified permissive/modifying genes, leads to a retinal degeneration), and documented their fundus appearance and the change with aging. Immunostaining of retinal pigment epithelium (RPE) flat mounts was done for 1) Ionized calcium binding adaptor (Iba)-1, 2) FcγIII/II Receptor (CD16/CD32, abbreviated as CD16), and 3) Macrophage mannose receptor (MMR). Reverse-transcription quantitative PCR (RT-qPCR) was done for genes involved in oxidative stress, complement activation and inflammation.

Results

The number of yellow fundus spots correlated highly with subretinal Iba-1+ cells. The total number of subretinal MG/MΦ increased with age in the rd8 mutant mice, but not in the wild-type (WT) mice. There was a centripetal shift in the distribution of the subretinal MG/MΦ with age. Old rd8 mutant mice had a greater number of CD16+ MG/MΦ. CD16+ cells had morphological signs of activation, and this was most prominent in old rd8 mutant mice (P <1×10⁻⁸ versus old WT mice). Subretinal MG/MΦ in rd8 mutant mice also expressed iNOS and MHC-II, and had ultrastructural signs of activation. Finally, rd8 mutant mouse RPE/ MG/MΦ RNA isolates showed an upregulation of Ccl2, CFB, C3, NF-kβ, CD200R and TNF-alpha. The retinas of rd8 mutant mice showed upregulation of HO-1, C1q, C4, and Nrf-2.

Conclusions

When compared to C57BL/6J mice, C57BL/6N mice demonstrate increased accumulation of subretinal MG/MΦ, displaying phenotypical, morphological, and gene-expression characteristics consistent with a pro-inflammatory shift. These changes become more prominent with aging and are likely due to the combination of the rd8 mutation and yet unidentified permissive/modulatory genes in the C57BL/6N mice. In contrast, aging leads to a scavenging phenotype in the C57BL/6J subretinal microglia/macrophages.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-014-0221-4) contains supplementary material, which is available to authorized users.

Melanoma cells influence the differentiation pattern of human epidermal keratinocytes

Background

Nodular melanoma is one of the most life threatening tumors with still poor therapeutic outcome. Similarly to other tumors, permissive microenvironment is essential for melanoma progression. Features of this microenvironment are arising from molecular crosstalk between the melanoma cells (MC) and the surrounding cell populations in the context of skin tissue. Here, we study the effect of melanoma cells on human primary keratinocytes (HPK). Presence of MC is as an important modulator of the tumor microenvironment and we compare it to the effect of nonmalignant lowly differentiated cells also originating from neural crest (NCSC).

Methods

Comparative morphometrical and immunohistochemical analysis of epidermis surrounding nodular melanoma (n = 100) was performed. Data were compared to results of transcriptome profiling of in vitro models, in which HPK were co-cultured with MC, normal human melanocytes, and NCSC, respectively. Differentially expressed candidate genes were verified by RT-qPCR. Biological activity of candidate proteins was assessed on cultured HPK.

Results

Epidermis surrounding nodular melanoma exhibits hyperplastic features in 90% of cases. This hyperplastic region exhibits aberrant suprabasal expression of keratin 14 accompanied by loss of keratin 10. We observe that MC and NCSC are able to increase expression of keratins 8, 14, 19, and vimentin in the co-cultured HPK. This in vitro finding partially correlates with pseudoepitheliomatous hyperplasia observed in melanoma biopsies. We provide evidence of FGF-2, CXCL-1, IL-8, and VEGF-A participation in the activity of melanoma cells on keratinocytes.

Conclusion

We conclude that the MC are able to influence locally the differentiation pattern of keratinocytes in vivo as well as in vitro. This interaction further highlights the role of intercellular interactions in melanoma. The reciprocal role of activated keratinocytes on biology of melanoma cells shall be verified in the future.

Electronic supplementary material

The online version of this article (doi:10.1186/1476-4598-14-1) contains supplementary material, which is available to authorized users.

Eye cancer incidence in U.S. states and access to fluoridated water

Environmental risk factors for uveal melanomas (cancer of the iris, ciliary body, and choroid) have not been identified. To search for these, we examined the correlation of age-adjusted eye cancer incidence rates, a surrogate for uveal melanoma rates, in U.S. states with group level geographic and demographic factors using multivariate linear regression. Incidence rates for eye cancer were inversely correlated with the percentage of the population receiving fluoridated water; that is, higher rates were found in states with lower prevalences of fluoridation (P = 0.01). Fluoride is known to inhibit the growth of microbial agents that cause choroiditis and choroidal lesions in animals. We speculate that fluoridation protects against choroidal melanoma by inhibiting microbial agents that cause choroiditis and/or choroidal lesions in humans.

In vitro methods of assessing ocular biocompatibility using THP-1-derived macrophages

Macrophages play an important role in the elimination of infections, the removal of debris and in tissue repair after infection and trauma. In vitro models that assess ocular biomaterials for toxicity typically focus on the effects of these materials on epithelial or fibroblast cells. This investigation evaluated known ocular toxins deposited on model materials for their effects on the viability and activation of macrophages. THP-1-derived macrophages were cultured onto silicone films (used as a base biomaterial) deposited with chemical toxins (benzalkonium chloride (BAK), zinc diethyldithiocarbamate (ZDEC) and lipopolysaccharide (LPS)). Utilizing three fluorescent dyes calcein, ethidium homodimer-1 (EthD-1) and annexin V, the viability of macrophages attached to the biomaterial was determined using confocal microscopy. Propidium iodide (PI) staining and alamarBlue® (resazurin) reduction were used to assess cell death and metabolic activity. CD14, CD16, CD33, CD45, and CD54 expression of adherent macrophages, were also evaluated to detect LPS activation of macrophages using flow cytometry. The sensitivity of this test battery was demonstrated as significant toxicity from treated surfaces with ZDEC (0.001-0.01%), and BAK (0.001%-0.1%) was detected. Also, macrophage activation could be detected by measuring CD54 expression after exposure to adsorbed LPS. These in vitro methods will be helpful in determining the toxicity potential of new ocular biomaterials.

Role of macrophages in uveal melanoma

Tumor-associated macrophages have been related to a worse prognosis for survival in several tumors, among them uveal melanoma. In particular for proangiogenic and anti-inflammatory M2-type macrophages, a contributory role to tumor growth has been described. This study demonstrated that most tumor-associated macrophages in uveal melanoma exhibited the M2-phenotype. Tumors with monosomy 3 that have an unfavorable prognosis exhibited significantly more M2-type macrophages than tumors with disomy of chromosome 3. These findings point to a possible pathophysiologic mechanism that links an inflammatory phenotype in uveal melanoma with structural chromosomal abnormalities such as monosomy 3.

Inflammation in uveal melanoma

Leukocytic infiltration is a common feature of human cancers, including those that develop in immunoprivileged sites, such as the eye. The infiltration of myeloid and T cells into tumours is part of the host response against cancer. In uveal melanoma, high densities of immune cells seem to be involved in tumour progression, as they are associated with the loss of one chromosome 3. The nature of this tumour microenvironment might offer therapeutic opportunities.

Molecular pathology of uveal melanoma

Like other cancers, uveal melanomas (UM) are characterised by an uncontrolled, clonal, cellular proliferation, occurring as a result of numerous genetic, and epigenetic aberrations. Signalling pathways known to be disrupted in UM include: (1) the retinoblastoma pathway, probably as a result of cyclin D1 overexpression; p53 signalling, possibly as a consequence of MDM2 overexpression; and the P13K/AKT and mitogen-activated protein kinase/extracellular signal-related kinase pathway pathways that are disturbed as a result of PTEN and GNAQ/11 mutations, respectively. Characteristic chromosomal abnormalities are common and include 6p gain, associated with a good prognosis, as well as 1p loss, 3 loss, and 8q gain, which correlate with high mortality. These are identified by techniques such as fluorescence in situ hybridisation, comparative genomic hybridisation, microsatellite analysis, multiplex ligation-dependent probe amplification, and single-nucleotide polymorphisms. UM can also be categorised by their gene expression profiles as class 1 or class 2, the latter correlating with poor survival, as do BRCA1-associated protein-1 (BAP1) inactivating mutations. Genetic testing of UM has enhanced prognostication, especially when results are integrated with histological and clinical data. The identification of abnormal signalling pathways, genes and proteins in UM opens the way for target-based therapies, improving prospects for conserving vision and prolonging life.

M2/M1 ratio of tumor associated macrophages and PPAR-gamma expression in uveal melanomas with class 1 and class 2 molecular profiles

Macrophages have been found to be negative predictors of outcome in patients with uveal melanoma. In particular, recent studies point toward a disease-progressing role of proangiogenic M2 macrophages in melanomas with monosomy 3. Although most studies implicate a protective effect of PPAR-gamma activation in tumors, PPAR-gamma has also been shown to promote the polarization of M1 macrophages toward the M2 phenotype. The purpose of this investigation was first, to characterize the phenotype of tumor infiltrating macrophages and second, to study PPAR-gamma expression in uveal melanomas with molecular gene expression profile as prognostic predictors for patients' outcome. Twenty specimens from patients with uveal melanoma were analyzed for clinical and histologic tumor characteristics. The molecular RNA profile (class 1 or class 2) was commercially determined. Using immunohistochemical techniques, the specimens were dual labeled for CD68 and CD163. CD68 + CD163- M1 macrophages and CD68 + CD163+ M2 macrophages were analyzed in ten high power fields sparing macrophage-poor areas and a mean value was calculated for each tumor. The tumors were immunostained for von Willebrand factor and the micro vascular density (MVD) was analyzed according to Foss. To assess the proliferative rate of each tumor, Ki67 expression was evaluated in ten high power fields followed by calculation of a mean value. Expression of PPAR-gamma was evaluated using a score from 0 (no staining) to 3 (tumor entirely stained). Statistical analysis and a respective correlation were made between histologic characteristics, molecular profile, type of tumor infiltrating macrophages (M1 vs. M2), MVD, proliferative rate, and PPAR-gamma expression. Our results showed a correlation between the ratio of M2/M1 macrophages and the molecular profile with a ratio of approximately 1 corresponding to molecular class 1 and a ratio of approximately 2 corresponding to molecular class 2 (p = 0.01). The ratio of M2/M1 macrophages was higher in tumors with extraocular extension (p = 0.01). PPAR-gamma was predominantly expressed in the cytoplasm of tumor cells. Its expression showed no association with the molecular RNA profile (p = 0.83). This study confirmed that the ratio of M2/M1 macrophages is another prognostic factor in uveal melanoma. Thus, polarization of macrophages plays an important role for patients' outcome. PPAR-gamma is expressed in uveal melanoma tumor cells and further studies are warranted to determine its role in tumor biology.

Good news-bad news: the Yin and Yang of immune privilege in the eye

The eye and the brain are prototypical tissues manifesting immune privilege (IP) in which immune responses to foreign antigens, particularly alloantigens are suppressed, and even completely inhibited. Explanations for this phenomenon are numerous and mostly reflect our evolving understanding of the molecular and cellular processes underpinning immunological responses generally. IP is now viewed as a property of many tissues and the level of expression of IP varies not only with the tissue but with the nature of the foreign antigen and changes in the limited conditions under which privilege can operate as a mechanism of immunological tolerance. As a result, IP functions normally as a homeostatic mechanism preserving normal function in tissues, particularly those with highly specialized function and limited capacity for renewal such as the eye and brain. However, IP is relatively easily bypassed in the face of a sufficiently strong immunological response, and the privileged tissues may be at greater risk of collateral damage because its natural defenses are more easily breached than in a fully immunocompetent tissue which rapidly rejects foreign antigen and restores integrity. This two-edged sword cuts its swathe through the eye: under most circumstances, IP mechanisms such as blood-ocular barriers, intraocular immune modulators, induction of T regulatory cells, lack of lymphatics, and other properties maintain tissue integrity; however, when these are breached, various degrees of tissue damage occur from severe tissue destruction in retinal viral infections and other forms of uveoretinal inflammation, to less severe inflammatory responses in conditions such as macular degeneration. Conversely, ocular IP and tumor-related IP can combine to permit extensive tumor growth and increased risk of metastasis thus threatening the survival of the host.

Costimulatory molecule expression on human uveal melanoma cells: functional analysis of CD40 and B7-H1

Costimulatory molecules play important roles in regulating T cell function in tumor immunity. In this study, we investigated costimulatory molecule expression on human uveal melanoma cells (a primary culture, and OCM-1, OMM-1 and 92-1 cell lines) and assessed the functional roles of selected costimulatory molecules. Uveal melanoma cells were incubated in the presence or absence of IFN-γ and expression of costimulatory molecules on the cells was measured by flow cytometry. The costimulatory effect of B7-H1-expressing uveal melanoma cells on cytokine production by purified T cells was studied in uveal melanoma/T cell co-culture experiments using a blocking anti-B7-H1 monoclonal antibody (mAb). The functional role of CD40-mediated interactions in modifying immune responses to uveal melanoma cells was assessed in vitro using recombinant human CD40 ligand (rhCD40L). MHC class I and B7-H1 were consistently detected and further upregulated by IFN-γ stimulation in all human uveal melanoma cell cultures. CD40 was consistently detected and further upregulated by IFN-γ stimulation in primary culture, OCM-1, and OMM-1 but not 92-1. IL-2 production from purified CD3(+) T cells co-stimulated with IFN-γ-treated uveal melanoma cells was significantly enhanced by the addition of anti-B7-H1 mAb. Treatment of primary culture, OCM-1, or OMM-1 with rhCD40L induced or enhanced secretion of chemokines IL-8, MCP-1, IP-10 and RANTES. These results suggest that the expression of B7-H1 on IFN-γ-treated uveal melanoma cells contributes to suppression of T cells by decreasing IL-2 production. In contrast, CD40 expressed on uveal melanoma cells plays an important role in augmenting anti-tumor immunity by stimulating chemokine production. The dual effects of CD40 and B7-H1 may contribute to positive or negative regulation of anti-tumor immune responses to human uveal melanoma.

Macrophage polarization in the maculae of age-related macular degeneration: a pilot study

Macrophages can be polarized to exhibit either pro-inflammatory M1 or pro-angiogenic M2 phenotypes, but have high phenotypic plasticity. This pilot study investigated macrophage polarization in the macular retina and choroid of age-related macular degeneration (AMD) and non-AMD subjects, as well as in AMD choroidal neovascular membranes (CNVM). All specimens were evaluated for routine histopathology. Quantitative real-time polymerase chain reaction for representative M1 (CXCL11) and M2 (CCL22) transcripts were performed on macular choroidal trephines (MCT) of 19 AMD and nine non-AMD eye bank eyes, on the microdissected macular retinal cells from the archived slides of five geographic atrophic AMD, five exudative/neovascular AMD, and eight normal autopsied eyes, and on microdissected inflammatory cells from two surgically removed CNVM that did not respond to anti-vascular endothelial growth factor (VEGF) therapy. High M2-chemokine transcript and a low ratio of M1 to M2 chemokine transcript were found in aging non-AMD MCT. Advanced AMD maculae had a higher M1 to M2 chemokine transcript ratio compared to normal autopsied eyes. Macrophages in the two CNVM of patients unresponsive to anti-VEGF therapy were polarized toward either M1 or M2 phenotypes. The number of M2 macrophages was increased compared to M1 macrophages in normal aging eyes. A pathological shift of macrophage polarization may play a potential role in AMD pathogenesis.