Intratumoral forkhead box P3-positive regulatory T cells predict poor survival in cyclooxygenase-2-positive uveal melanoma

Correlation of the abundance of MDSCs, Tregs, PD-1, and PD-L1 with the efficacy of chemotherapy and prognosis in gastric cancer

OBJECTIVE

The aim of this study was to investigate the relationship between tumor microenvironment markers (myeloid-derived suppressor cells [MDSCs], regulatory T cells [Tregs], programmed cell death 1 [PD-1], and programmed death ligand 1 [PD-L1]) and chemotherapy efficacy and prognosis in advanced gastric cancer, identifying potential monitoring indicators.

METHODS

Advanced gastric cancer patients' MDSC and Treg expression was measured by flow cytometry pre- and postchemotherapy; PD-1 and PD-L1 expression in cancer tissues was assessed by immunohistochemistry. Correlations with chemotherapy outcomes and prognosis were analyzed.

RESULTS

Postchemotherapy reductions in MDSC and Treg levels correlated with chemotherapy efficacy (P <.01). Negative PD-1 and PD-L1 expression in cancer tissues predicted better chemotherapy responses (P <.01). Patients with lower MDSC and Treg levels and negative PD-1 and PD-L1 had significantly longer median progression-free survival (PFS) and overall survival (OS) (P <.05).

CONCLUSION

In advanced gastric cancer, reduced peripheral blood MDSC and Treg levels postchemotherapy and negative PD-1 and PD-L1 expression in tissues are associated with improved chemotherapy efficacy and are independent prognostic factors for PFS and OS.

[Uveal melanoma and its local inflammation - good or bad for the patient?]

The 21st century is characterized by the study of the features of malignant tumor infiltration by cellular components of the immune system. While some findings suggest a favorable role of lymphoid infiltration in tumors and its positive impact on survival due to immune defense, the opposite is observed in uveal melanoma (UM): lymphoid infiltration significantly worsens the patient's prognosis. Research on this topic is limited, with some studies confined to experimental models.

PURPOSE

This study investigated the correlation between microRNA-155 expression in the plasma of UM patients after primary enucleation and with pathomorphological inflammatory changes.

MATERIAL AND METHODS

Eighty-three patients with UM were examined, in 21 cases lymphoid infiltration of the primary tumor was detected, in 6 cases accompanied by a microenvironment. The degree of tumor infiltration with lymphocytes was estimated as a percentage of the total number of cells in the analyzed field, ranging from 1% to 25%. Real-time polymerase chain reaction was used to determine microRNA-155 expression in the plasma of all patients before and after enucleation, and its correlation with the level of lymphoid infiltration was analyzed. Postoperative follow-up lasted 6 to 53 months (mean 21.5±14.9 months). In two cases, in the presence of a tumor microenvironment, metastases to the liver were detected 6 and 10 months after enucleation. MicroRNA-155 levels in a volunteer group were used as the control baseline, set at 100% for clarity and convenience.

RESULTS

MicroRNA-155 expression levels were higher in patients with lymphoid infiltration (p<0.05) and tended to increase with the degree of primary tumor infiltration (p<0.001), which in itself, with the appearance of a perifocal lymphoid environment, indicated a poor prognosis.

CONCLUSION

Monitoring microRNA-155 expression levels in the plasma of UM patients may help predict occult metastasis prior to enucleation. This is not only crucial for clinical follow-up but may also play a significant role in the development of targeted therapies.

FOXP3+/CD8+ ratio associated with aggressive behavior in RUNX3-methylated diffuse esophagogastric junction tumor

The tumor immune microenvironment is increasingly becoming a key consideration in developing treatment regimens for aggressive cancers, with evidence that regulatory T cells (Tregs) attenuate the antitumor response by interrupting cytotoxic T cells (CD8+). Here, we hypothesized the prognostic relevance of the proportions of Tregs (marked by forkhead box protein 3 [FOXP3]) and CD8+ cells in diffuse, non-Epstein-Barr virus (EBV)/non-microsatellite instability (MSI)-high gastroesophageal adenocarcinomas (GEAs), which are clinically characterized as more aggressive, immunologically inactive tumors as compared with their intestinal counterparts. Cell-count ratios of FOXP3+/CD8+ expression were calculated at the intratumoral region and invasive margin discretely on digital images from 303 chemo-naive non-EBV/non-MSI-high esophagogastric junction (EGJ) adenocarcinomas. A significant modifying prognostic effect of tumor histology was observed between 5-year EGJ cancer-specific survival and the FOXP3+/CD8+ ratio at the invasive margin in pStage I-III tumors (p for interaction = 0.022; hazard ratio [HR] = 8.47 and 95% confidence interval [CI], 2.04-35.19 for high ratio [vs. low] for diffuse; HR = 1.57 and 95% CI, 0.88-2.83 for high ratio [vs. low] for intestinal). A high FOXP3+/CD8+ ratio at the invasive margin was associated with RUNX3 methylation (p = 0.035) and poor prognosis in RUNX3-methylated diffuse histological subtype (5-year EGJ cancer-specific survival, 52.3% for high and 100% for low, p = 0.015). Multiomics data from The Cancer Genome Atlas linked CCL28 with RUNX3-suppressed diffuse histological subtypes of non-EBV/non-MSI-high GEA. Our data suggest that a high FOXP3+/CD8+ ratio at the invasive margin might indicate tumor immune escape via CCL28, particularly in the RUNX3-methylated diffuse histological subtype.

Regulatory T cells subgroups in the tumor microenvironment cannot be overlooked: Their involvement in prognosis and treatment strategy in melanoma

BACKGROUND

Melanoma, the most lethal form of skin cancer, presents substantial challenges despite effective surgical interventions for in situ lesions. Regulatory T cells (Tregs) wield a pivotal immunomodulatory influence within the tumor microenvironment, yet their impact on melanoma prognosis and direct molecular interactions with melanoma cells remain elusive. This investigation employs single-cell analysis to unveil the intricate nature of Tregs in human melanoma.

METHODS

Single-cell RNA and bulk sequencing data, alongside clinical information, were obtained from public repositories. Initially, GO and GSEA analyses were employed to delineate functional disparities among distinct cell subsets. Pseudotime and cell-cell interconnection analyses were conducted, followed by an endeavor to construct a prognostic model grounded in Treg-associated risk scores. This model's efficacy was demonstrated via PCA and K-M analyses, with multivariate Cox regression affirming its independent prognostic value in melanoma patients. Furthermore, immune infiltration analysis, immune checkpoint gene expression scrutiny, and drug sensitivity assessments were performed to ascertain the clinical relevance of this prognostic model.

RESULTS

Following batch effect correction, 80 025 cells partitioned into 31 clusters, encompassing B cells, plasma cells, endothelial cells, fibroblasts, melanoma cells, monocytes, macrophages, and T_NK cells. Within these, 4240 CD4+ T cells were subclassified into seven distinct types. Functional analysis underscored the immunomodulatory function of Tregs within the melanoma tumor microenvironment, elucidating disparities among Treg subpopulations. Notably, the ITGB2 signaling pathway emerged as a plausible molecular nexus linking Tregs to melanoma cells. Our prognostic signature exhibited robust predictive capacities for melanoma prognosis and potential implications in evaluating immunotherapy response.

CONCLUSION

Tregs exert a critical role in immune suppression within the melanoma tumor microenvironment, revealing a potential molecular-level association with melanoma cells. Our innovative Treg-centered signature introduces a promising prognostic marker for melanoma, holding potential for future clinical prognostic assessments.

Identifying biomarkers for treatment of uveal melanoma by T cell engager using a QSP model

Uveal melanoma (UM), the primary intraocular tumor in adults, arises from eye melanocytes and poses a significant threat to vision and health. Despite its rarity, UM is concerning due to its high potential for liver metastasis, resulting in a median survival of about a year after detection. Unlike cutaneous melanoma, UM responds poorly to immune checkpoint inhibition (ICI) due to its low tumor mutational burden and PD-1/PD-L1 expression. Tebentafusp, a bispecific T cell engager (TCE) approved for metastatic UM, showed potential in clinical trials, but the objective response rate remains modest. To enhance TCE efficacy, we explored quantitative systems pharmacology (QSP) modeling in this study. By integrating a TCE module into an existing QSP model and using clinical data on UM and tebentafusp, we aimed to identify and rank potential predictive biomarkers for patient selection. We selected 30 important predictive biomarkers, including model parameters and cell concentrations in tumor and blood compartments. We investigated biomarkers using different methods, including comparison of median levels in responders and non-responders, and a cutoff-based biomarker testing algorithm. CD8+ T cell density in the tumor and blood, CD8+ T cell to regulatory T cell ratio in the tumor, and naïve CD4+ density in the blood are examples of key biomarkers identified. Quantification of predictive power suggested a limited predictive power for single pre-treatment biomarkers, which was improved by early on-treatment biomarkers and combination of predictive biomarkers. Ultimately, this QSP model could facilitate biomarker-guided patient selection, improving clinical trial efficiency and UM treatment outcomes.

The Phenotypical Characterization of Dual-Nature Hybrid Cells in Uveal Melanoma

BACKGROUND

Metastasis, occurring years after primary diagnosis, represents a poor prognosis in uveal melanoma (UM)-affected individuals. The nature of cells involved in this process is under debate. Circulating hybrid cells that have combined tumor and immune cell features found in blood were predictive of metastasis and may correspond to dual-nature cells (DNC) in the primary tumor. Herein, we sought to determine the presence of DNCs in primary UM tumors, the cell types involved in their genesis, and their ability to be formed in vitro.

METHODS

UM lesions (n = 38) were immunolabeled with HMB45 in combination with immune-cell-specific antibodies. In parallel, we co-cultured UM cells and peripheral blood mononuclear cells (PBMCs) to analyze DNC formation.

RESULTS

HMB45+/CD45+ DNCs were present in 90% (26/29) of the tumors, HMB45+/CD8+ DNCs were present in 93% (26/28), and HMB45+/CD68+ DNCs were present in 71% (17/24). DNCs formed with CD8+ and CD68+ cells were positively correlated to the infiltration of their respective immune cells. Notably, UM cells were prone to hybridize with PBMCs in vitro.

CONCLUSIONS

This phenotypical characterization of DNCs in UM demonstrates that CD8+ T-cells and macrophages are capable of DNC formation, and they are important for better understanding metastatic dissemination, thus paving the path towards novel therapeutic avenues.

PD-L1 targeted peptide demonstrates potent antitumor and immunomodulatory activity in cancer immunotherapy

Background

In recent years, immunotherapy has been emerging as a promising alternative therapeutic method for cancer patients, offering potential benefits. The expression of PD-L1 by tumors can inhibit the T-cell response to the tumor and allow the tumor to evade immune surveillance. To address this issue, cancer immunotherapy has shown promise in disrupting the interaction between PD-L1 and its ligand PD-1.

Methods

We used mirror-image phage display technology in our experiment to screen and determine PD-L1 specific affinity peptides (PPL-C). Using CT26 cells, we established a transplanted mouse tumor model to evaluate the inhibitory effects of PPL-C on tumor growth in vivo. We also demonstrated that PPL-C inhibited the differentiation of T regulatory cells (Tregs) and regulated the production of cytokines.

Results

In vitro, PPL-C has a strong affinity for PD-L1, with a binding rate of 0.75 μM. An activation assay using T cells and mixed lymphocytes demonstrated that PPL-C inhibits the interaction between PD-1 and PD-L1. PPL-C or an anti-PD-L1 antibody significantly reduced the rate of tumor mass development in mice compared to those given a control peptide (78% versus 77%, respectively). The results of this study demonstrate that PPL-C prevents or retards tumor growth. Further, immunotherapy with PPL-C enhances lymphocyte cytotoxicity and promotes proliferation in CT26-bearing mice.

Conclusion

PPL-C exhibited antitumor and immunoregulatory properties in the colon cancer. Therefore, PPL-C peptides of low molecular weight could serve as effective cancer immunotherapy.

Identifying endoplasmic reticulum stress-related molecular subtypes and prognostic model for predicting the immune landscape and therapy response in pancreatic cancer

Endoplasmic reticulum stress (ERS) is caused by the accumulation of intracellular misfolded or unfolded proteins and is associated with cancer development. In this study, pan-cancer analysis revealed complex genetic variations, including copy number variation, methylation, and somatic mutations for ERS-related genes (ERGs) in 33 kinds of cancer. Consensus clustering divided pancreatic cancer (PC) patients from TCGA and GEO databases into two ERS-related subtypes: ERGcluster A and B. Compared with ERGcluster A, ERGcluster B had a more active ERS state and worse prognosis. Subsequently, the ERS-related prognostic model was established to quantify the ERS score for a single sample. The patient with a low ERS score had remarkably longer survival times. ssGSEA and CIBERSORT algorithms revealed that activated B cells and CD8+ T cells had higher infiltration in the low ERS score group, but higher infiltration of activated CD4+ T cells, activated dendritic cells, macrophages, and neutrophils in the high ERS score group. Drug sensitivity analysis indicated the low ERS score group had a better response to gemcitabine, paclitaxel, 5-fluorouracil, oxaliplatin, and irinotecan. RT-qPCR validated that MET, MUC16, and KRT7 in the model had higher expression levels in pancreatic tumour tissues. Single-cell analysis further revealed that MET, MUC16, and KRT7 were mainly expressed in cancer cells in PC tumour microenvironment. In all, we first constructed the ERS-related molecular subtypes and prognostic model in PC. Our research highlighted the vital role of ERS in PC and contributed to further research on molecular mechanisms and novel therapeutic strategies for PC in the future.

"To be or not to Be": Regulatory T cells in melanoma

In spite of progresses in the therapy of different malignancies, melanoma still remains as one of lethal types of skin tumor. Melanoma is almost easily treatable by surgery alone with higher overall survival rates when it is diagnosed at early stages. However, survival rates are decreased remarkably upon survival if the tumor is progressed to advanced metastatic stages. Immunotherapeutics have been prosperous in the development of anti-tumor responses in patients with melanoma through promotion of the tumor-specific effector T cells in vivo; nonetheless, suitable clinical outcomes have not been satisfactory. One of the underlying causes of the unfavorable clinical outcomes might stem from adverse effects of regulatory T (Treg) cell, which is a prominent mechanism of tumor cells to escape from tumor-specific immune responses. Evidence shows that a poor prognosis and low survival rate in patients with melanoma can be attributed to a higher Treg cell number and function in these subjects. As a result, to promote melanoma-specific anti-tumor responses, depletion of Treg cells appears to be a promising approach; even though the clinical efficacy of different approaches to attain appropriate Treg cell depletion has been inconsistent. Here in this review, the main purpose is to assess the role of Treg cells in the initiation and perpetuation of melanoma and to discuss effective strategies for Treg cell modulation with the aim of melanoma therapy.

What Are the Roles of Proprotein Convertases in the Immune Escape of Tumors?

Protein convertases (PCs) play a significant role in post-translational procedures by transforming inactive precursor proteins into their active forms. The role of PCs is crucial for cellular homeostasis because they are involved in cell signaling. They have also been described in many diseases such as Alzheimer's and cancer. Cancer cells are secretory cells that send signals to the tumor microenvironment (TME), remodeling the surrounding space for their own benefits. One of the most important components of the TME is the immune system of the tumor. In this review, we describe recent discoveries that link PCs to the immune escape of tumors. Among PCs, many findings have determined the role of Furin (PC3) as a paramount enzyme causing the TME to induce tumor immune evasion. The overexpression of various cytokines and proteins, for instance, IL10 and TGF-B, moves the TME towards the presence of Tregs and, consequently, immune tolerance. Furthermore, Furin is implicated in the regulation of macrophage activity that contributes to the increased impairment of DCs (dendritic cells) and T effector cells. Moreover, Furin interferes in the MHC Class_1 proteolytic cleavage in the trans-Golgi network. In tumors, the T cytotoxic lymphocytes (CTLs) response is impeded by the PD1 receptor (PD1-R) located on CTLs and its ligand, PDL1, located on cancer cells. The inhibition of Furin is a subtle means of enhancing the antitumor response by repressing PD-1 expression in tumors or macrophage cells. The impacts of other PCs in tumor immune escape have not yet been clarified to the extent that Furin has. Accordingly, the influence of other types of PCs in tumor immune escape is a promising topic for further consideration.

Prostaglandin E2 directly inhibits the conversion of inducible regulatory T cells through EP2 and EP4 receptors via antagonizing TGF-β signalling

Regulatory T (Treg) cells are essential for control of inflammatory processes by suppressing effector T-cell functions. The actions of PGE2 on the development and function of Treg cells, particularly under inflammatory conditions, are debated. In this study, we employed pharmacological and genetic approaches to examine whether PGE2  had a direct action on T cells to modulate de novo differentiation of Treg cells. We found that TGF-β-induced Foxp3 expression and iTreg cell differentiation in vitro is markedly inhibited by PGE2 , which was mediated by the receptors EP2 and EP4. Mechanistically, PGE2 -EP2/EP4 signalling interrupts TGF-β signalling during iTreg differentiation. Moreover, EP4 deficiency in T cells impaired iTreg cell differentiation in vivo. Thus, our results demonstrate that PGE2 negatively regulates iTreg cell differentiation through a direct action on T cells, highlighting the potential for selectively targeting the PGE2 -EP2/EP4 pathway to control T cell-mediated inflammation.

Tumor-derived extracellular vesicles regulate tumor-infiltrating regulatory T cells via the inhibitory immunoreceptor CD300a

Although tumor-infiltrating regulatory T (Treg) cells play a pivotal role in tumor immunity, how Treg cell activation are regulated in tumor microenvironments remains unclear. Here, we found that mice deficient in the inhibitory immunoreceptor CD300a on their dendritic cells (DCs) have increased numbers of Treg cells in tumors and greater tumor growth compared with wild-type mice after transplantation of B16 melanoma. Pharmacological impairment of extracellular vesicle (EV) release decreased Treg cell numbers in CD300a-deficient mice. Coculture of DCs with tumor-derived EV (TEV) induced the internalization of CD300a and the incorporation of EVs into endosomes, in which CD300a inhibited TEV-mediated TLR3–TRIF signaling for activation of the IFN-β-Treg cells axis. We also show that higher expression of CD300A was associated with decreased tumor-infiltrating Treg cells and longer survival time in patients with melanoma. Our findings reveal the role of TEV and CD300a on DCs in Treg cell activation in the tumor microenvironment.

DNAJB11 predicts a poor prognosis and is associated with immune infiltration in thyroid carcinoma: a bioinformatics analysis

Objective

To investigate the prognostic value of the co-chaperone protein DnaJ Heat Shock Protein Family (Hsp40) Member B11 (DNAJB11) in thyroid carcinoma (THCA).

Methods

This bioinformatics analysis study evaluated the prognostic value of DNAJB11 mRNA levels in THCA based on data from The Cancer Genome Atlas (TCGA). The levels of DNAJB11 mRNA in THCA and normal tissues were compared with Wilcoxon signed rank test. Kaplan–Meier survival curve analysis and Cox regression analysis were performed to evaluate the correlation between DNAJB11 mRNA levels and survival. Gene Ontology (GO) enrichment analysis was used to elucidate the functional enrichment difference.

Results

Data from the 502 patients with THCA from the TCGA database were analysed. DNAJB11 mRNA was downregulated in THCA tissues compared with normal tissues. Decreased levels of DNAJB11 mRNA were significantly correlated with T stage, N stage, pathological stage, histological type, extrathyroidal extension and BRAF gene status. The low levels of DNAJB11 mRNA were associated with a shorter progression-free interval. GO enrichment analysis showed that DNAJB11 was involved in immune-related biological processes.

Conclusion

Low levels of DNAJB11 mRNA were associated with poor prognosis in THCA.

CTLA-4 in Regulatory T Cells for Cancer Immunotherapy

Immune checkpoint inhibitors (ICIs) have obtained durable responses in many cancers, making it possible to foresee their potential in improving the health of cancer patients. However, immunotherapies are currently limited to a minority of patients and there is a need to develop a better understanding of the basic molecular mechanisms and functions of pivotal immune regulatory molecules. Immune checkpoint cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and regulatory T (Treg) cells play pivotal roles in hindering the anticancer immunity. Treg cells suppress antigen-presenting cells (APCs) by depleting immune stimulating cytokines, producing immunosuppressive cytokines and constitutively expressing CTLA-4. CTLA-4 molecules bind to CD80 and CD86 with a higher affinity than CD28 and act as competitive inhibitors of CD28 in APCs. The purpose of this review is to summarize state-of-the-art understanding of the molecular mechanisms underlining CTLA-4 immune regulation and the correlation of the ICI response with CTLA-4 expression in Treg cells from preclinical and clinical studies for possibly improving CTLA-4-based immunotherapies, while highlighting the knowledge gap.

The dark side of daylight: photoaging and the tumor microenvironment in melanoma progression

Continued thinning of the atmospheric ozone, which protects the earth from damaging ultraviolet radiation (UVR), will result in elevated levels of UVR reaching the earth's surface, leading to a drastic increase in the incidence of skin cancer. In addition to promoting carcinogenesis in skin cells, UVR is a potent extrinsic driver of age-related changes in the skin known as "photoaging." We are in the preliminary stages of understanding of the role of intrinsic aging in melanoma, and the tumor-permissive effects of photoaging on the skin microenvironment remain largely unexplored. In this Review, we provide an overview of the impact of UVR on the skin microenvironment, addressing changes that converge or diverge with those observed in intrinsic aging. Intrinsic and extrinsic aging promote phenotypic changes to skin cell populations that alter fundamental processes such as melanogenesis, extracellular matrix deposition, inflammation, and immune response. Given the relevance of these processes in cancer, we discuss how photoaging might render the skin microenvironment permissive to melanoma progression.

Trial watch: Prognostic and predictive value of the immune infiltrate in cancer

Solid tumors are constituted of a variety of cellular components, including bona fide malignant cells as well as endothelial, structural and immune cells. On one hand, the tumor stroma exerts major pro-tumorigenic and immunosuppressive functions, reflecting the capacity of cancer cells to shape the microenvironment to satisfy their own metabolic and immunological needs. On the other hand, there is a component of tumor-infiltrating leucocytes (TILs) that has been specifically recruited in the attempt to control tumor growth. Along with the recognition of the critical role played by the immune system in oncogenesis, tumor progression and response to therapy, increasing attention has been attracted by the potential prognostic and/or predictive role of the immune infiltrate in this setting. Data from large clinical studies demonstrate indeed that a robust infiltration of neoplastic lesions by specific immune cell populations, including (but not limited to) CD8⁺ cytotoxic T lymphocytes, Th1 and Th17 CD4⁺ T cells, natural killer cells, dendritic cells, and M1 macrophages constitutes an independent prognostic indicator in several types of cancer. Conversely, high levels of intratumoral CD4⁺CD25⁺FOXP3⁺ regulatory T cells, Th2 CD4⁺ T cells, myeloid-derived suppressor cells, M2 macrophages and neutrophils have frequently been associated with dismal prognosis. So far, only a few studies have addressed the true predictive potential of TILs in cancer patients, generally comforting the notion that—at least in some clinical settings—the immune infiltrate can reliably predict if a specific patient will respond to therapy or not. In this Trial Watch, we will summarize the results of clinical trials that have evaluated/are evaluating the prognostic and predictive value of the immune infiltrate in the context of solid malignancies.

Distribution pattern of tumor infiltrating lymphocytes and tumor microenvironment composition as prognostic indicators in anorectal malignant melanoma

Anorectal malignant melanoma (ARMM) is a rare disease with poor prognosis. Determining ARMM prognosis precisely is difficult due to the lack of proper assessment techniques. Immunotherapy has proven effective against cutaneous malignant melanoma and may show efficacy in ARMM. Herein, we assessed the immune profile of ARMM to identify possible prognostic biomarkers. Twenty-two ARMM formalin-fixed and paraffin-embedded samples were evaluated using an nCounter^® PanCancer Immune Profiling Panel. Validation was performed through immunohistochemical staining for CD3, CD8, Foxp3, CD68, CD163, and PD-L1. RNA analysis revealed significantly decreased scores for pathways involved in cell regulation and function, as well as chemokines, in recurrent patients compared to nonrecurrent patients. In cell-type profiling, the recurrent cases displayed significantly low tumor infiltrating lymphocyte (TIL) scores. Recurrence/death prediction models were defined using logistic regression and showed significantly lower scores in recurrent and deceased patients (all, P < 0.001) compared to those in nonrecurrent and surviving patients. The high total TIL and tumor-associated macrophage (TAM) groups had significantly better overall survival outcomes compared to the low total TIL and TAM groups (P = 0.007 and P = 0.035, respectively). In addition, the presence of CD3 + TILs in the invasion front was an independent favorable prognostic indicator (P = 0.003, hazard ratio = 0.21, 95% confidential interval, 0.01-0.41). Patients with inflamed or brisk-infiltration type tumors also had a significantly better overall survival than that of patients with immune-desert/excluded and absent/non-brisk type tumors (P = 0.03 and P = 0.0023, respectively). In conclusion, TILs have a strong prognostic value in ARMM, and the quantification of TILs and an analysis of the TIL phenotype and infiltration pattern during pathological diagnosis are essential to guide treatment strategies and accurate prognosis in ARMM.

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.

Update on uveal melanoma: Translational research from biology to clinical practice (Review)

Uveal melanoma is the most common type of intraocular cancer with a low mean annual incidence of 5‑10 cases per million. Tumours are located in the choroid (90%), ciliary body (6%) or iris (4%) and of 85% are primary tumours. As in cutaneous melanoma, tumours arise in melanocytes; however, the characteristics of uveal melanoma differ, accounting for 3‑5% of melanocytic cancers. Among the numerous risk factors are age, sex, genetic and phenotypic predisposition, the work environment and dermatological conditions. Management is usually multidisciplinary, including several specialists such as ophthalmologists, oncologists and maxillofacial surgeons, who participate in the diagnosis, treatment and complex follow‑up of these patients, without excluding the management of the immense emotional burden. Clinically, uveal melanoma generates symptoms that depend as much on the affected ocular globe site as on the tumour size. The anatomopathological study of uveal melanoma has recently benefited from developments in molecular biology. In effect, disease classification or staging according to molecular profile is proving useful for the assessment of this type of tumour. Further, the improved knowledge of tumour biology is giving rise to a more targeted approach to diagnosis, prognosis and treatment development; for example, epigenetics driven by microRNAs as a target for disease control. In the present study, the main epidemiological, clinical, physiopathological and molecular features of this disease are reviewed, and the associations among all these factors are discussed.

Accumulation of TNFR2-expressing regulatory T cells in malignant pleural effusion of lung cancer patients is associated with poor prognosis

Background

Regulatory T cells (Tregs) may represent a major cellular mechanism in immune suppression by dampening the anti-tumor response in malignant pleural effusion (MPE). Tumor necrosis factor receptor type II (TNFR2) has emerged as a novel identification for the maximally suppressive subset of Tregs in the tumor environment. At present, the significance of TNFR2 expression on Tregs in MPE remains unclear.

Methods

The distribution of TNFR2⁺cells in Tregs and effector T cells (Teffs) in MPE, peripheral blood (PB), and tuberculosis pleural effusion (TPE) were determined. The associations between TNFR2⁺Tregs frequencies present in MPE and the clinical and laboratorial characteristics of patients with lung cancer were investigated. The immunosuppressive phenotype of TNFR2⁺Tregs in MPE was analyzed. The effects of the TNF-TNFR2 interaction on the immunosuppressive function of Tregs was explored. The efficacy of targeting TNFR2 for MPE therapy was examined. The source of TNF in MPE was identified.

Results

We observed that markedly higher levels of TNFR2 were expressed in MPE Tregs compared with the levels expressed in MPE Teffs, PB Tregs, or in TPE Tregs. The frequencies of TNFR2⁺Tregs were positively correlated with the number of tumor cells in MPE, as well as the volume of MPE. High frequencies of TNFR2⁺Tregs in MPE indicated short survival time and poor performance status for MPE patients. Compared to TNFR2^-Tregs, TNFR2⁺Tregs expressed higher levels of immunosuppressive molecules cytotoxic T lymphocyte-associated protein 4 (CTLA-4), programmed cell death-ligand 1 (PD-L1), and replicating marker Ki-67. Consequently, the proportions of interferon gamma (IFN-γ)-producing cytotoxic T lymphocytes (CTLs) were significantly increased after TNFR2 blockade. Furthermore, tumor necrosis factor (TNF), through interaction with TNFR2, enhanced the suppressive capacity of Tregs by up-regulating CTLA-4 and PD-L1 expression. Interestingly, T helper 1 (Th1) and T helper 17 (Th17) cells are the major source of TNF in MPE, suggesting that MPE Teffs may paradoxically promote tumor growth by boosting MPE Treg activity via the TNF-TNFR2 pathway.

Conclusions

Our data expanded the immunosuppressive mechanism present in MPE induced by Tregs, and provides novel insight for the diagnosis, disease evaluation, and treatment of MPE patients.

Intrahepatic TH17/TReg Cells in Homeostasis and Disease-It's All About the Balance

Both acute and chronic hepatic inflammation likely result from an imbalance in the T_H1/T_H2 cell response and can lead to liver fibrosis and end-stage liver disease. More recently, a novel CD4+ T helper cell subset was described, characterized by the production of IL-17 and IL-22. These T_H17 cells 50were predominantly implicated in host defense against infections and in autoimmune diseases. Interestingly, studies over the last 10 years revealed that the development of T_H17 cells favors pro-inflammatory responses in almost all tissues and there is a reciprocal relationship between T_H17 and T_Reg cells. The balance between T_H17and T_Reg cells is critical for immune reactions, especially in injured liver tissue and the return to immune homeostasis. The pathogenic contribution of T_H17 and T_Reg cells in autoimmunity, acute infection, and chronic liver injury is diverse and varies among disease etiologies. Understanding the mechanisms underlying T_H17 cell development, recruitment, and maintenance, along with the suppression of T_Reg cells, will inform the development of new therapeutic strategies in liver diseases. Active manipulation of the balance between pathogenic and regulatory processes in the liver may assist in the restoration of homeostasis, especially in hepatic inflammation.

Uveal melanoma: progress in molecular biology and therapeutics

Uveal melanoma (UM) is the most common intraocular malignancy in adults. So far, no systemic therapy or standard treatment exists to reduce the risk of metastasis and improve overall survival of patients. With the increased knowledge regarding the molecular pathways that underlie the oncogenesis of UM, it is expected that novel therapeutic approaches will be available to conquer this disease. This review provides a summary of the current knowledge of, and progress made in understanding, the pathogenesis, genetic mutations, epigenetics, and immunology of UM. With the advent of the omics era, multi-dimensional big data are publicly available, providing an innovation platform to develop effective targeted and personalized therapeutics for UM patients. Indeed, recently, a great number of therapies have been reported specifically for UM caused by oncogenic mutations, as well as other etiologies. In this review, special attention is directed to advancements in targeted therapies. In particular, we discuss the possibilities of targeting: GNAQ/GNA11, PLCβ, and CYSLTR2 mutants; regulators of G-protein signaling; the secondary messenger adenosine diphosphate (ADP)-ribosylation factor 6 (ARF6); downstream pathways, such as those involving mitogen-activated protein kinase/MEK/extracellular signal-related kinase, protein kinase C (PKC), phosphoinositide 3-kinase/Akt/mammalian target of rapamycin (mTOR), Trio/Rho/Rac/Yes-associated protein, and inactivated BAP1; and immune-checkpoint proteins cytotoxic T-lymphocyte antigen 4 and programmed cell-death protein 1/programmed cell-death ligand 1. Furthermore, we conducted a survey of completed and ongoing clinical trials applying targeted and immune therapies for UM. Although drug combination therapy based on the signaling pathways involved in UM has made great progress, targeted therapy is still an unmet medical need.

Role of the Cyclooxygenase Pathway in the Association of Obstructive Sleep Apnea and Cancer

The objective of this review is to examine the findings that link obstructive sleep apnea (OSA) with cancer and the role played by the cyclooxygenase (COX) pathway in this association. Epidemiological studies in humans suggest a link between OSA and increased cancer incidence and mortality. Studies carried out in animal models have shown that intermittent hypoxia (IH) induces changes in several signaling pathways involved in the regulation of host immunological surveillance that results in tumor establishment and invasion. IH induces the expression of cyclooxygenase 2 (COX-2) that results in an increased synthesis of prostaglandin E2 (PGE2). PGE2 modulates the function of multiple cells involved in immune responses including T lymphocytes, NK cells, dendritic cells, macrophages, and myeloid-derived suppressor cells. In a mouse model blockage of COX-2/PGE2 abrogated the pro-oncogenic effects of IH. Despite the fact that aspirin inhibits PGE2 production and prevents the development of cancer, none of the epidemiological studies that investigated the association of OSA and cancer included aspirin use in the analysis. Studies are needed to investigate the regulation of the COX-2/PGE2 pathway and PGE2 production in patients with OSA, to better define the role of this axis in the physiopathology of OSA and the potential role of aspirin in preventing the development of cancer.

Immunohistochemical detectability of cyclooxygenase-2 expression in cells of human melanocytic skin lesions: A methodological review

Increased cyclooxygenase-2 (COX-2) expression is thought to support tumorigenesis through various mechanisms and is analyzed as a potential cancer marker. In 18 studies, COX-2 expression in melanocytic lesions of human skin was examined immunohistochemically. However, results obtained by individual research groups differ in terms of detection frequency and level of this protein, as well as localization of stained cells within tumor. Possible reasons for the discrepancies are analyzed in this review: the application of different antibodies, the use of standard histopathological sections or tissue microarrays and the analyzes of staining results based on different algorithms. COX-2 level is significantly lower in nevi than in melanomas, increases gradually with progression of these malignant cancers and reaches the highest values in metastases. These gradual changes in COX-2 expression appear to be difficult to analyze based only on subjective assessment of staining intensity. The most convergent data were obtained using antibodies for N-terminal fragments of COX-2 protein and analyzing results based on calculation of percentage fraction of positive cells. The extent of stained area in specimen thus appears to be more important than the intensity of staining in terms of evaluation of COX-2 performance as a diagnostic and prognostic marker of cutaneous melanoma.

Aqueous Humor Biomarkers Identify Three Prognostic Groups in Uveal Melanoma

Purpose

To investigate whether we can identify different patterns of inflammation in the aqueous humor of a uveal melanoma (UM)-containing eye, and whether these are related to prognosis.

Methods

Ninety samples of aqueous humor from UM-containing eyes were analyzed using a high-throughput multiplex immunoassay that enables simultaneous analysis of 92 predefined protein biomarkers. Cytokine expression was compared to clinical and histopathological characteristics. Cluster analysis was performed, after which the clusters were compared with clinical and histopathological tumor characteristics.

Results

Cluster analysis revealed three distinct clusters, with one cluster showing hardly any inflammatory cytokines, one showing intermediate levels, and one showing a high expression of inflammation-related biomarkers. Significant differences between the clusters were seen with regard to patient age (P = 0.008), tumor prominence (P = 0.001), ciliary body involvement (P < 0.001), American Joint Committee on Cancer (AJCC) stage (P < 0.001), monosomy of chromosome 3 (P = 0.03), and gain of chromosome 8q (P = 0.04), with the cluster with a highest cytokine expression having the worst prognostic markers. Especially apoptosis-related cytokines were differentially expressed.

Conclusions

Analysis of cytokines in the aqueous humor shows distinct differences between aqueous humor samples and allocates these samples into three different prognostic tumor clusters. Especially large tumors with ciliary body involvement and monosomy 3 were associated with many cytokines, especially apoptosis-related cytokines. The presence of these cytokines in the aqueous humor may play a role in the lack of effective antitumor immune responses.

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.

Endoplasmic Reticulum Stress Pathway, the Unfolded Protein Response, Modulates Immune Function in the Tumor Microenvironment to Impact Tumor Progression and Therapeutic Response

Despite advances in cancer therapy, several persistent issues remain. These include cancer recurrence, effective targeting of aggressive or therapy-resistant cancers, and selective treatments for transformed cells. This review evaluates the current findings and highlights the potential of targeting the unfolded protein response to treat cancer. The unfolded protein response, an evolutionarily conserved pathway in all eukaryotes, is initiated in response to misfolded proteins accumulating within the lumen of the endoplasmic reticulum. This pathway is initially cytoprotective, allowing cells to survive stressful events; however, prolonged activation of the unfolded protein response also activates apoptotic responses. This balance is key in successful mammalian immune response and inducing cell death in malignant cells. We discuss how the unfolded protein response affects cancer progression, survival, and immune response to cancer cells. The literature shows that targeting the unfolded protein response as a monotherapy or in combination with chemotherapy or immunotherapies increases the efficacy of these drugs; however, systemic unfolded protein response targeting may yield deleterious effects on immune cell function and should be taken into consideration. The material in this review shows the promise of both approaches, each of which merits further research.

Ki67 expression and localization of T cells after neoadjuvant therapies as reliable predictive markers in rectal cancer

Chemoradiotherapy (CRT) is the standard neoadjuvant therapy for locally advanced rectal cancer (RC). However, neoadjuvant chemotherapy (NAC) also shows favorable outcomes. Although the immunological environment of RC has been thoroughly discussed, the effect of NAC on it is less clear. Here, we investigated the immunological microenvironment, including T cell infiltration, activation, and topological distribution, of resected RC tissue after neoadjuvant therapies and evaluated the correlation between T cell subsets and patient prognosis. Rectal cancer patients (n = 188) were enrolled and categorized into 3 groups, namely CRT (n = 41), NAC (n = 46), and control (surgery alone; n = 101) groups. Characterization of residual carcinoma cells and T cell subsets in resected tissues was performed using multiplex fluorescence immunohistochemistry. The densities of total and activated (Ki67^high) T cells in tissues after NAC, but not CRT, were higher than in control. In both CRT and NAC groups, patients presenting with higher treatment effects showed aggressive infiltration of T cell subsets into carcinomas. Multivariate analyses of pathological and immunological features and prognosis revealed that carcinoma Ki67^highCD4⁺ T cells after CRT and stromal Ki67^highCD8⁺ T cells after NAC are important prognostic factors, respectively. Our results suggest that evaluation of T cell activation with Ki67 expression and its tumor localization can be used to determine the prognosis of advanced RC after neoadjuvant 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.

Uveal Versus Cutaneous Melanoma; Same Origin, Very Distinct Tumor Types

Here, we critically evaluated the knowledge on cutaneous melanoma (CM) and uveal melanoma (UM). Both cancer types derive from melanocytes that share the same embryonic origin and display the same cellular function. Despite their common origin, both CM and UM display extreme differences in their genetic alterations and biological behavior. We discuss the differences in genetic alterations, metastatic routes, tumor biology, and tumor-host interactions in the context of their clinical responses to targeted- and immunotherapy.

PTEN-deficient prostate cancer is associated with an immunosuppressive tumor microenvironment mediated by increased expression of IDO1 and infiltrating FoxP3+ T regulatory cells

BACKGROUND

Accumulating evidence shows that tumor cell-specific genomic changes can influence the cross talk between cancer cells and the surrounding tumor microenvironment (TME). Loss of the PTEN tumor suppressor gene is observed in 20% to 30% of prostate cancers (PCa) when first detected and the rate increases with PCa progression and advanced disease. Recent findings implicate a role for PTEN in cellular type I interferon response and immunosuppression in PCa. However, the way that PTEN inactivation alters antitumor immune response in PCa is poorly understood.

MATERIALS AND METHODS

To investigate the changes associated with PTEN loss and an immunosuppressive TME in PCa, we used CIBERSORT to estimate the relative abundance of 22 immune-cell types from 741 primary and 96 metastatic tumors. Our in silico findings were then validated by immunohistochemical analysis of immune cells and IDO1 and PDL1 checkpoint proteins in a cohort of 94 radical prostatectomy specimens.

RESULTS

FoxP3+ T regulatory cells (Tregs) were significantly increased in PTEN-deficient PCa in all three public domain cohorts. Loss of PTEN in bone metastases was associated with lower CD8+ T-cell abundance, but in liver metastasis, FoxP3+ Tregs were present at higher levels. PTEN-deficient lymph node metastasis had a distinct profile, with high levels of CD8+ T cells. Moreover, we found that metastatic PCa presents higher abundance of FoxP3+ Treg when compared to primary lesions. Since PTEN-deficient tumors are likely to be immunosuppressed as a consequence of increased FoxP3+ Tregs, we then evaluated the localization and expression of IDO1, PDL1 immune checkpoints, and the corresponding density of FoxP3+ Treg and CD8+ T cells using our validation cohort (n = 94). We found that IDO1 protein expression and FoxP3+ Treg density were higher in neoplastic glands compared with benign adjacent tissue. Moreover, higher densities of FoxP3+ Treg cells in both stromal (P = 0.04) and tumor (P = 0.006) compartments were observed in PTEN-deficient tumors compared to tumors that retained PTEN activity. Similarly, IDO1 protein expression was significantly increased in the tumor glands of PTEN-deficient PCa (P < 0.0001). Spearman correlation analysis showed that IDO1 expression was significantly associated with FoxP3+ Treg and CD8+ T-cell density (P < 0.01).

CONCLUSIONS

Our findings imply that PTEN deficiency is linked to an immunosuppressive state in PCa with distinct changes in the frequency of immune cell types in tumors from different metastatic sites. Our data suggest that determining PTEN status may also help guide the selection of patients for future immunotherapy trials in localized and metastatic PCa.

Prognostic value of tumor-infiltrating lymphocytes in melanoma: a systematic review and meta-analysis

Tumor-infiltrating lymphocytes (TILs) are associated with prognosis in various tumors. However, it remains controversial whether the presence of TILs is related to an improved prognosis in melanoma. This meta-analysis confirmed the favorable prognostic role of the CD3+, CD4+, CD8+, FOXP3+, and CD20+ TILs in the overall survival of melanoma patients and found an association between the TILs present and improved overall survival. Additionally, subgroup analysis demonstrated that brisk TILs were obviously associated with OS, RFS and DSS/MSS. Thus, TILs may be a predictive biomarker in melanoma. This analysis will provide more insight into the study of TILs and predictive biomarker.

CD8+ cytotoxic T lymphocytes in cancer immunotherapy: A review

CD8⁺ cytotoxic T lymphocytes (CTLs) are preferred immune cells for targeting cancer. During cancer progression, CTLs encounter dysfunction and exhaustion due to immunerelated tolerance and immunosuppression within the tumor microenvironment (TME), with all favor adaptive immune-resistance. Cancer-associated fibroblasts (CAFs), macrophage type 2 (M2) cells, and regulatory T cells (Tregs) could make immunologic barriers against CD8 ⁺ T cell-mediated antitumor immune responses. Thus, CD8 ⁺ T cells are needed to be primed and activated toward effector CTLs in a process called tumor immunity cycle for making durable and efficient antitumor immune responses. The CD8 ⁺ T cell priming is directed essentially as a corroboration work between cells of innate immunity including dendritic cells (DCs) and natural killer (NK) cells with CD4 ⁺ T cells in adoptive immunity. Upon activation, effector CTLs infiltrate to the core or invading site of the tumor (so-called infiltrated-inflamed [I-I] TME) and take essential roles for killing cancer cells. Exogenous reactivation and/or priming of CD8 ⁺ T cells can be possible using rational immunotherapy strategies. The increase of the ratio for costimulatory to coinhibitory mediators using immune checkpoint blockade (ICB) approach. Programmed death-1 receptor (PD-1)-ligand (PD-L1) and CTL-associated antigen 4 (CTLA-4) are checkpoint receptors that can be targeted for relieving exhaustion of CD8 ⁺ T cells and renewing their priming, respectively, and thereby eliminating antigen-expressing cancer cells. Due to a diverse relation between CTLs with Tregs, the Treg activity could be dampened for increasing the number and rescuing the functional potential of CTLs to induce immunosensitivity of cancer cells.

Crosstalk between PPARγ Ligands and Inflammatory-Related Pathways in Natural T-Regulatory Cells from Type 1 Diabetes Mouse Model

Immunomodulation, as a means of immunotherapy, has been studied in major research and clinical laboratories for many years. T-Regulatory (Treg) cell therapy is one of the modulators used in immunotherapy approaches. Similarly, nuclear receptor peroxisome proliferator activated receptor gamma (PPARγ) has extensively been shown to play a role as an immuno-modulator during inflammation. Given their mutual roles in downregulating the immune response, current study examined the influence of PPARγ ligands i.e., thiazolidinedione (TZD) class of drugs on Forkhead Box P3 (Foxp3) expression and possible crosstalk between PPARγ and nTreg cells of Non-Obese Diabetes (NOD) and Non-Obese Diabetes Resistant (NOR) mice. Results showed that TZD drug, ciglitazone and natural ligand of PPARγ 15d-prostaglandin downregulated Foxp3 expression in activated nTreg cells from both NOD and NOR mice. Interestingly, addition of the PPARγ inhibitor, GW9662 further downregulated Foxp3 expression in these cells from both mice. We also found that PPARγ ligands negatively regulate Foxp3 expression in activated nTreg cells via PPARγ-independent mechanism(s). These results demonstrate that both natural and synthetic PPARγ ligands capable of suppressing Foxp3 expression in activated nTreg cells of NOD and NOR mice. This may suggest that the effect of PPARγ ligands in modulating Foxp3 expression in activated nTreg cells is different from their reported effects on effector T cells. Given the capability to suppress Foxp3 gene, it is possible to be tested as immunomodulators in cancer-related studies. The co-lateral use of PPARγ ligands in nTreg cells in inducing tolerance towards pseudo-self antigens as in tumor microenvironment may uphold beneficial outcomes.

Contribution of regulatory T cells to cancer: A review

Regulatory T cells (Tregs) represent a low number of T-cell population under normal conditions, and they play key roles for maintaining immune system in homeostasis. The number of these cells is extensively increased in nearly all cancers, which is for dampening responses from immune system against cancer cells, metastasis, tumor recurrence, and treatment resistance. The interesting point is that apoptotic Tregs are stronger than their live counterparts for suppressing responses from immune system. Tregs within the tumor microenvironment have extensive positive cross-talks with other immunosuppressive cells including cancer-associated fibroblasts, cancer cells, macrophage type 2 cells, and myeloid-derived suppressor cells, and they have negative interactions with immunostimulatory cells including cytotoxic T lymphocytes (CTL) and natural killer cells. A wide variety of markers are expressed in Tregs, among them forkhead box P3 (FOXP3) is the most specific marker and the master regulator of these cells. Multiple signals are activated by Tregs including transforming growth factor-β, signal transducer and activator of transcription, and mTORC1. Treg reprogramming from an immunosuppressive to immunostimulatory proinflammatory phenotype is critical for increasing the efficacy of immunotherapy. This would be applicable through selective suppression of tumor-bearing receptors in Tregs, including FOXP3, programmed death-1, T-cell immunoglobulin mucin-3, and CTL-associated antigen-4, among others. Intratumoral Tregs can also be targeted by increasing the ratio for CTL/Treg.

Tumor-infiltrating Treg, MDSC, and IDO expression associated with outcomes of neoadjuvant chemotherapy of breast cancer

BACKGROUND

Regulatory T cells(Tregs) and myeloid-derived suppressor cells(MDSCs) represent two immunosuppressive cell populations that are important in the establishment and maintenance of cancer immune tolerance. MDSCs can express IDO and promote immune tolerance via expansion of Treg cell.

METHOD

We use needle biopsy breast cancer tissues prior to neoadjuvant chemotherapy(NCT) staining for CD33, Foxp3 and IDO by immunohistochemistry to evaluate whether they were correlated with subsequent treatment responses in breast cancer.

RESULTS

Expressions of IDO, CD33⁺MDSCs and Foxp3⁺Tregs were correlated with each other. Immunohistochemical double staining revealed that IDO expression in CD33⁺MDSCs was positively correlated with Foxp3⁺Tregs (P < 0.05). CD33⁺MDSCs, Foxp3⁺Tregs, and IDO expression in tumor tissues were associated with advanced clinical stage prior to NCT (P < 0.05). CD33⁺MDSCs, Foxp3⁺Tregs, IDO expression, IDO expression in CD33⁺MDSCs and clinical T3-T4 stage prior to NCT, pathological T3-T4 stage, ER(+), luminal type were correlated with clinical responses of PD+SD (P < 0.05). Multivariate analysis showed that CD33⁺MDSCs, IDO expression, IDO expression in CD33⁺MDSCs, and advanced pathological T stage were risk factors for PD+SD. Focusing on the pCR of NCT, only CD33⁺MDSCs, clinical T3-T4, and N1-N3 stage prior to NCT were associated with no-pCR (P < 0.05). The multivariate analysis showed that advanced clinical T stage and N stage were risk factors for no-pCR. Clinical stage prior to NCT were significantly correlated with progression free survival (P = 0.021), while Foxp3⁺Tregs and clinical T stage were significantly correlated with overall survival (P = 0.022 and P = 0.001, respectively). Foxp3+Treg was significant risk factor for overall survival after adjusting covariates by COX regression.

CONCLUSION

Tumor-infiltrating MDSCs, Tregs, IDO expression and IDO expression in MDSCs were correlated with clinicopathological features, NCT response, and prognosis of breast cancer patients, suggesting that they might be potential markers for clinical outcomes of NCT and help clinical decision-making for improved therapies for breast cancer.

Tumour-infiltrating regulatory T cell density before neoadjuvant chemoradiotherapy for rectal cancer does not predict treatment response

Neoadjuvant (preoperative) chemoradiotherapy (CRT) decreases the risk of rectal cancer recurrence and reduces tumour volume prior to surgery. However, response to CRT varies considerably between individuals and factors associated with response are poorly understood. Foxp3+ regulatory T cells (Tregs) inhibit anti-tumour immunity and may limit any response to chemotherapy and radiotherapy. We have previously reported that a low density of Tregs in the tumour stroma following neoadjuvant CRT for rectal cancer is associated with improved tumour regression. Here we have examined the association between Treg density in pre-treatment diagnostic biopsy specimens and treatment response, in this same patient cohort. We aimed to determine whether pre-treatment tumour-infiltrating Treg density predicts subsequent response to neoadjuvant CRT. Foxp3+, CD8+ and CD3+ cell densities in biopsy samples from 106 patients were assessed by standard immunohistochemistry (IHC) and evaluated for their association with tumour regression grade and survival. We found no association between the density of any T cell subset pre-treatment and clinical outcome, indicating that tumour-infiltrating Treg density does not predict response to neoadjuvant CRT in rectal cancer. Taken together with the findings of the previous study, these data suggest that in the context of neoadjuvant CRT for rectal cancer, the impact of chemotherapy and/or radiotherapy on anti-tumour immunity may be more important than the state of the pre-existing local immune response.

Expanding Diversity and Common Goal of Regulatory T and B Cells. II: In Allergy, Malignancy, and Transplantation

Regulation of immune response was found to play an important role in the course of many diseases such as autoimmune diseases, allergy, malignancy, organ transplantation. The studies on immune regulation focus on the role of regulatory cells (Tregs, Bregs, regulatory myeloid cells) in these disorders. The number and function of Tregs may serve as a marker of disease activity. As in allergy, the depletion of Tregs is observed and the results of allergen-specific immunotherapy could be measured by an increase in the population of IL-10⁺ regulatory cells. On the basis of the knowledge of anti-cancer immune response regulation, new directions in therapy of tumors are introduced. As the proportion of regulatory cells is increased in the course of neoplasm, the therapeutic action is directed at their inhibition. The depletion of Tregs may be also achieved by an anti-check-point blockade, anti-CD25 agents, and inhibition of regulatory cell recruitment to the tumor site by affecting chemokine pathways. However, the possible favorable role of Tregs in cancer development is considered and the plasticity of immune regulation should be taken into account. The new promising direction of the treatment based on regulatory cells is the prevention of transplant rejection. A different way of production and implementation of classic Tregs as well as other cell types such as double-negative cells, Bregs, CD4⁺ Tr1 cells are tested in ongoing trials. On the basis of the results of current studies, we could show in this review the significance of therapies based on regulatory cells in different disorders.

Uveal Melanoma: Identifying Immunological and Chemotherapeutic Targets to Treat Metastases

Uveal melanoma is an intraocular malignancy that, depending on its size and genetic make-up, may lead to metastases in up to 50% of cases. Currently, no therapy has been proven to improve survival. However, new therapies exploiting immune responses against metastases are being developed. The primary tumor is well characterized: tumors at high risk of developing metastases often contain macrophages and lymphocytes. However, these lymphocytes are often regulatory T cells that may suppress immune response. Currently, immune checkpoint inhibitors have shown marked efficacy in multiple cancers (eg, cutaneous melanoma) but do not yet improve survival in uveal melanoma patients. More knowledge needs to be acquired regarding the function of T cells in uveal melanoma. Other therapeutic options are related to the biochemical pathways. Targeting the RAF-MEK-ERK pathway with small molecule MEK inhibitors abrogates the growth of UM cells harboring GNAQ/GNA11 Q209 mutations, suggesting that these aberrant G-protein oncogenes mediate, at least in part, their effect through this hallmark proliferation pathway. Other pathways are also implicated, such as those involving c-Jun and YAP. Further studies may show how interference in the different pathways may affect survival.

The biology of uveal melanoma

Uveal melanoma (UM), a rare cancer of the eye, is distinct from cutaneous melanoma by its etiology, the mutation frequency and profile, and its clinical behavior including resistance to targeted therapy and immune checkpoint blockers. Primary disease is efficiently controlled by surgery or radiation therapy, but about half of UMs develop distant metastasis mostly to the liver. Survival of patients with metastasis is below 1 year and has not improved in decades. Recent years have brought a deep understanding of UM biology characterized by initiating mutations in the G proteins GNAQ and GNA11. Cytogenetic alterations, in particular monosomy of chromosome 3 and amplification of the long arm of chromosome 8, and mutation of the BRCA1-associated protein 1, BAP1, a tumor suppressor gene, or the splicing factor SF3B1 determine UM metastasis. Cytogenetic and molecular profiling allow for a very precise prognostication that is still not matched by efficacious adjuvant therapies. G protein signaling has been shown to activate the YAP/TAZ pathway independent of HIPPO, and conventional signaling via the mitogen-activated kinase pathway probably also contributes to UM development and progression. Several lines of evidence indicate that inflammation and macrophages play a pro-tumor role in UM and in its hepatic metastases. UM cells benefit from the immune privilege in the eye and may adopt several mechanisms involved in this privilege for tumor escape that act even after leaving the niche. Here, we review the current knowledge of the biology of UM and discuss recent approaches to UM treatment.

Dinitrophenyl hapten with laser immunotherapy for advanced malignant melanoma: A clinical study

The present study aimed to evaluate the efficacy and safety of in situ immunotherapy with dinitrophenyl (DNP) hapten in combination with laser therapy for patients with malignant melanoma (MM). Between February 2008 and March 2012, 72 patients with stage III or IV MM were enrolled. Patients received in situ DNP alone (n=32) or in combination with laser therapy (n=32), and each group received dacarbazine chemotherapy. The levels of peripheral cluster of differentiation (CD)4⁺CD25⁺ regulatory T cells (Tregs), interleukin (IL)-10 and tumor growth factor (TGF)-β were detected by ELISA. The association between delayed-type hypersensitivity (DTH) and survival time was evaluated. Although peripheral Treg levels significantly decreased over time in the two groups (P<0.001), there was no significant difference between the treatment groups (P=0.098). Patients receiving the combination treatment exhibited significantly higher interferon-γ production by CD8⁺ and CD4⁺ T cells (both P<0.001), as well as significantly reduced levels of IL-10, TGF-β1 and TGF-β2. In addition, patients in the combination treatment group experienced significantly longer overall survival (OS; P=0.024) and disease-free survival (DFS; P=0.007) times; a DTH response of ≥15 mm was also associated with increased OS time and DFS time (P≤0.001). Finally, no severe adverse events were observed in either treatment group. Overall, in situ immunization with DNP in combination with laser immunotherapy may activate focal T cells, producing a regional antitumor immune response that increases cell-mediated immunity and improves survival in MM patients. Thus, this may represent a novel therapeutic strategy for patients with unresectable, advanced MM.

Upregulation of HLA Expression in Primary Uveal Melanoma by Infiltrating Leukocytes

Introduction

Uveal melanoma (UM) with an inflammatory phenotype, characterized by infiltrating leukocytes and increased human leukocyte antigen (HLA) expression, carry an increased risk of death due to metastases. These tumors should be ideal for T-cell based therapies, yet it is not clear why prognostically-infaust tumors have a high HLA expression. We set out to determine whether the level of HLA molecules in UM is associated with other genetic factors, HLA transcriptional regulators, or microenvironmental factors.

Methods

28 enucleated UM were used to study HLA class I and II expression, and several regulators of HLA by immunohistochemistry, PCR microarray, qPCR and chromosome SNP-array. Fresh tumor samples of eight primary UM and four metastases were compared to their corresponding xenograft in SCID mice, using a PCR microarray and SNP array.

Results

Increased expression levels of HLA class I and II showed no dosage effect of chromosome 6p, but, as expected, were associated with monosomy of chromosome 3. Increased HLA class I and II protein levels were positively associated with their gene expression and with raised levels of the peptide-loading gene TAP1, and HLA transcriptional regulators IRF1, IRF8, CIITA, and NLRC5, revealing a higher transcriptional activity in prognostically-bad tumors. Implantation of fresh human tumor samples into SCID mice led to a loss of infiltrating leukocytes, and to a decreased expression of HLA class I and II genes, and their regulators.

Conclusion

Our data provides evidence for a proper functioning HLA regulatory system in UM, offering a target for T-cell based therapies.

Association of tumor and plasma microRNA expression with tumor monosomy-3 in patients with uveal melanoma

BACKGROUND

Epigenetic events mediated by methylation and histone modifications have been associated with the development of metastasis in patients with uveal melanoma. The role of epigenetic events mediated by microRNA (miR) is less clear. Tumor and plasma miR expression was examined in patients with primary uveal melanoma with tumor monosomy-3, a predictor of metastasis.

RESULTS

miR profiling of tumors by microarray found six miRs over-expressed and 19 under-expressed in 33 tumors with monosomy-3 compared to 22 without. None of the miRs differentially expressed in tumors with and without monosomy-3 was differentially expressed in tumors with and without tumor infiltrating lymphocytes. Tumors manifesting monosomy-3 were also characterized by higher levels of TARBP2 and DDX17 and by lower levels of XPO5 and HIWI, miR biogenesis factors. miR profiling of plasma by a quantitative nuclease protection assay found elevated levels of 11 miRs and reduction in four in patients with tumor monosomy-3. Only three miRs differentially expressed in the tumor arrays were detectable in plasma. miRs implicated in uveal melanoma development were not differentially expressed. Elevated plasma levels in patients with tumor monosomy-3 of miR-92b, identified in the tumor array, and of miR-199-5p and miR-223, identified in the plasma array, were confirmed by quantitative real-time polymerase chain reaction. Levels were also higher in patients compared to normal controls.

CONCLUSIONS

These results support a role for epigenetic mechanisms in the development of metastasis in patients with uveal melanoma and the analysis of miRs as biomarkers of metastatic risk. They also suggest that potentially useful blood miRs may be derived from the host response as well as the tumor.

Molecular Mechanisms for cAMP-Mediated Immunoregulation in T cells - Role of Anchored Protein Kinase A Signaling Units

The cyclic AMP/protein kinase A (cAMP/PKA) pathway is one of the most common and versatile signal pathways in eukaryotic cells. A-kinase anchoring proteins (AKAPs) target PKA to specific substrates and distinct subcellular compartments providing spatial and temporal specificity for mediation of biological effects channeled through the cAMP/PKA pathway. In the immune system, cAMP is a potent negative regulator of T cell receptor-mediated activation of effector T cells (Teff) acting through a proximal PKA/Csk/Lck pathway anchored via a scaffold consisting of the AKAP Ezrin holding PKA, the linker protein EBP50, and the anchoring protein phosphoprotein associated with glycosphingolipid-enriched microdomains holding Csk. As PKA activates Csk and Csk inhibits Lck, this pathway in response to cAMP shuts down proximal T cell activation. This immunomodulating pathway in Teff mediates clinically important responses to regulatory T cell (Treg) suppression and inflammatory mediators, such as prostaglandins (PGs), adrenergic stimuli, adenosine, and a number of other ligands. A major inducer of T cell cAMP levels is PG E2 (PGE2) acting through EP2 and EP4 prostanoid receptors. PGE2 plays a crucial role in the normal physiological control of immune homeostasis as well as in inflammation and cancer immune evasion. Peripherally induced Tregs express cyclooxygenase-2, secrete PGE2, and elicit the immunosuppressive cAMP pathway in Teff as one tumor immune evasion mechanism. Moreover, a cAMP increase can also be induced by indirect mechanisms, such as intercellular transfer between T cells. Indeed, Treg, known to have elevated levels of intracellular cAMP, may mediate their suppressive function by transferring cAMP to Teff through gap junctions, which we speculate could also be regulated by PKA/AKAP complexes. In this review, we present an updated overview on the influence of cAMP-mediated immunoregulatory mechanisms acting through localized cAMP signaling and the therapeutical increasing prospects of AKAPs disruptors in T-cell immune function.

Ocular diseases: immunological and molecular mechanisms

Many factors, such as environmental, microbial and endogenous stress, antigen localization, can trigger the immunological events that affect the ending of the diverse spectrum of ocular disorders. Significant advances in understanding of immunological and molecular mechanisms have been researched to improve the diagnosis and therapy for patients with ocular inflammatory diseases. Some kinds of ocular diseases are inadequately responsive to current medications; therefore, immunotherapy may be a potential choice as an alternative or adjunctive treatment, even in the prophylactic setting. This article first provides an overview of the immunological and molecular mechanisms concerning several typical and common ocular diseases; second, the functions of immunological roles in some of systemic autoimmunity will be discussed; third, we will provide a summary of the mechanisms that dictate immune cell trafficking to ocular local microenvironment in response to inflammation.

Cyclooxygenase-2 promotes tumor growth and suppresses tumor immunity

Cyclooxygenase-2 (COX-2), an inducible form of the enzyme that catalyzes the first step in the synthesis of prostanoids, is associated with inflammatory diseases and carcinogenesis, which is suspected to promote angiogenesis and tissue invasion of tumors and resistance to apoptosis. Meanwhile, COX-2 contributes to immune evasion and resistance to cancer immunotherapy, which plays a crucial role in the innate and adaptive immune response. The activity of COX-2-PGE2-EP signal pathway can suppress Dendritic cells (DCs), natural killer (NK), T cells, type-1 immunity excluding type-2 immunity which promote tumor immune evasion. COX-2 and the prostaglandin cascade play important roles in the "inflammogenesis of cancer". In addition, COX-inhibitors can inhibit tumor immune evasion. Therefore, we can exert the COX-inhibitors to facilitate the patients to benefit from addition of COX-inhibitors to standard cytotoxic therapy.