Regulatory T cells in the immunotherapy of melanoma

Dysregulated brain regulatory T cells fail to control reactive gliosis following repeated antigen stimulation

This study was undertaken to investigate the role of CD4+FoxP3+ regulatory T cells (Tregs) in regulating neuroinflammation during viral Ag-challenge and re-challenge. CD8⁺ lymphocytes persisting within tissues are designated tissue-resident memory T cells (T_RM), within brain: bT_RM. Reactivation of bT_RM with T cell epitope peptides generates rapid antiviral recall, but repeated stimulation leads to cumulative dysregulation of microglial activation, proliferation, and prolonged neurotoxic mediator production. Here, we show Tregs were recruited into murine brains following prime-CNS boost, but displayed altered phenotypes following repeated Ag-challenge. In response to repeated Ag, brain Tregs (bTregs) displayed inefficient immunosuppressive capacity, along with reduced expression of suppression of tumorigenicity 2 (ST2) and amphiregulin (Areg). Ex vivo Areg treatment revealed reduced production of neurotoxic mediators such as iNOS, IL-6, and IL-1β, and decreased microglial activation and proliferation. Taken together, these data indicate bTregs display an unstable phenotype and fail to control reactive gliosis in response to repeated Ag-challenge.

Shaping the Future of Immunotherapy Targets and Biomarkers in Melanoma and Non-Melanoma Cutaneous Cancers

Recent advances in treating cutaneous melanoma have resulted in impressive patient survival gains. Refinement of disease staging and accurate patient risk classification have significantly improved our prognostic knowledge and ability to accurately stratify treatment. Undoubtedly, the most important step towards optimizing patient outcomes has been the advent of cancer immunotherapy, in the form of immune checkpoint inhibition (ICI). Immunotherapy has established its cardinal role in the management of both early and late-stage melanoma. Through leveraging outcomes in melanoma, immunotherapy has also extended its benefit to other types of skin cancers. In this review, we endeavor to summarize the current role of immunotherapy in melanoma and non-melanoma skin cancers, highlight the most pertinent immunotherapy-related molecular biomarkers, and lastly, shed light on future research directions.

Biomarkers for Diagnosis, Prognosis and Response to Immunotherapy in Melanoma

Cutaneous Melanoma classification is constantly looking for specific and sensitive biomarkers capable of having a positive effect on diagnosis, prognosis and risk assessment, eventually affecting clinical outcome. Classical morphological, immunohistochemical and the well-known BRAF and NRAS genetic biomarkers do not allow the correct categorization of patients, being melanoma conditioned by high genetic heterogeneity. At the same time, classic prognostic methods are unsatisfactory. Therefore, new advances in omics and high-throughput analytical techniques have enabled the identification of numerous possible biomarkers, but their potentiality needs to be validated and standardized in prospective studies. Melanoma is considered an immunogenic tumor, being the first form of cancer to take advantage of the clinical use of the immune-checkpoint blockers. However, as immunotherapy is effective only in a limited number of patients, biomarkers associated with different responses are essential to select the more promising therapeutic approach and maximize clinical benefits. In this review, we summarize the most utilized biomarkers for Cutaneous Melanoma diagnosis, focusing on new prognostic and predictive biomarkers mainly associated with immunotherapy.

Blockade of transforming growth factor β2 by anti-sense oligonucleotide improves immunotherapeutic potential of IL-2 against melanoma in a humanized mouse model

BACKGROUND AIMS

IL-2 is a potent cytokine that activates natural killer cells and CD8+ cytotoxic T lymphocytes (CTLs) and has been approved for the treatment of metastatic renal cell carcinoma and metastatic melanoma. However, the medical use of IL-2 is restricted because of its narrow therapeutic window and potential side effects, including the expansion of regulatory T cells (Tregs).

METHODS

In this study, the authors investigated the complementary effects of transforming growth factor-β2 (TGF-β2) anti-sense oligodeoxynucleotide (TASO) on the immunotherapeutic potential of IL-2 in a melanoma-bearing humanized mouse model.

RESULTS

The authors observed that the combination of TASO and IL-2 facilitated infiltration of CTLs into the tumor, thereby potentiating the tumor killing function of CTLs associated with increased granzyme B expression. In addition, TASO attenuated the increase in Tregs by IL-2 in the peripheral blood and spleen and also inhibited infiltration of Tregs into the tumor, which was partly due to decreased CCL22. Alteration of T-cell constituents at the periphery by TGF-β2 inhibition combined with IL-2 might be associated with the synergistic augmentation of serum pro-inflammatory cytokines (such as interferon γ and tumor necrosis factor α) and decreased ratio of Tregs to CTLs in tumor tissues, which consequently results in significant inhibition of tumor growth CONCLUSIONS: These results indicate that the application of TASO improves IL-2-mediated anti-tumor immunity, thus implying that blockade of TGF-β2 in combination with IL-2 may be a promising immunotherapeutic strategy for melanoma.

Listing Malignant Melanoma Patients for Renal Transplantation

BACKGROUND

Melanoma is an immune responsive malignancy and the need for immunosuppression for successful transplantation may lead to recurrent disease. The recommended waiting time is unknown with various groups recommending anywhere from no wait to 5 years.

METHODS

In this single-center, retrospective observational study all kidney transplant recipients' charts from 1991 to 2015 were reviewed for a diagnosis of melanoma before transplantation. The charts were reviewed for the clinical characteristics of melanoma pre transplantation, induction immunosuppression, maintenance immunosuppression, graft function, death, and recurrence of melanoma.

RESULTS

Thirteen patients with a history of melanoma underwent kidney transplantation during this period. Recipients had been in remission for an average of 7.0 years (range, 10 months to 20 years, median 6 years). Approximately 61.5% received a living donor transplant, antithymocyte globulin was administered in 23.1% of recipients, and the remaining 76.9% received basiliximab. Melanoma recurred in 1 patient (7.7%). Maintenance immunosuppression varied, but only 2 patients remained on standard triple therapy with prednisone, calcineurin inhibitor, and antimetabolite therapy. Average follow-up time since transplant was 7.5 years, with 1 patient death 9 years post transplant from sepsis.

CONCLUSION

In conclusion, with our center demonstrates safety of kidney transplantation in patients with a prior history of localized melanoma and shorter waiting time. In malignant melanoma stage 0 and 1, waiting the recommended 5 years from the time of remission to kidney transplantation should be reconsidered.

Tre2-Bub2-Cdc16 Family Proteins Based Nomogram Serve as a Promising Prognosis Predicting Model for Melanoma

Tre2-Bub2-Cdc16 (TBC) proteins are conserved in eukaryotic organisms and function as negative feedback dominating the GAPs for Rab GTPases, while the function of TBC proteins in melanoma remains unclear. In this study, we observed the differential expression of 33 TBC genes in TCGA datasets classified by clinical features. Seven prognostic-associated TBC genes were identified by LASSO Cox regression analysis. Mutation analysis revealed distinctive frequency alteration in the seven prognostic-associated TBCs between cases with high and low scores. High-risk score and cluster 1 based on LASSO Cox regression and consensus clustering analysis were relevant to clinical features and unfavorable prognosis. GSVA analysis showed that prognostic-associated TBCs were related to metabolism and protein transport signaling pathway. Correlation analysis indicated the relationship between the prognostic-associated TBCs with RAB family members, invasion-related genes and immune cells. The prognostic nomogram model was well established to predict survival in melanoma. What's more, interference of one of the seven TBC proteins TBC1D7 was confirmed to inhibit the proliferation, migration and invasion of melanoma cells in vitro. In summary, we preliminarily investigated the impact of TBCs on melanoma through multiple bioinformatics analysis and experimental validation, which is helpful for clarifying the mechanism of melanoma and the development of anti-tumor drugs.

Biomarkers, measured during therapy, for response of melanoma patients to immune checkpoint inhibitors: a systematic review

Immune checkpoint inhibitors (ICIs), which target CTLA-4 or PD-(L)1 molecules, have shown impressive therapeutic results. Durable responses, however, are only observed in a segment of the patient population and must be offset against severe off-target immune toxicity and high costs. This calls for biomarkers that predict response during ICI treatment. Although many candidate biomarkers exist, as yet, there has been no systematic overview of biomarkers predictive during. Here, we provide a systematic review of the current literature of ICI treatment to establish an overview of candidate predictive biomarkers during ICI treatment in melanoma patients. We performed a systematic Medline search (2000-2018, 1 January) on biomarkers for survival or response to ICI treatment in melanoma patients. We retrieved 735 publications, of which 79 were finally included in this systematic review. Blood markers were largely studied for CTLA-4 ICI, whereas tumor tissue markers were analyzed for PD-(L)1 ICI. Blood cytology and soluble factors were more frequently correlated to overall survival (OS) than response, indicating their prognostic rather than predictive nature. An increase in tumor-infiltrating CD8 + T-cells and a decrease in regulatory T-cells were correlated to response, in addition to mutational load, neoantigen load, and immune-related gene expression. Immune-related adverse events were also associated frequently with a favorable response and OS. This review shows the great variety of potential biomarkers published to date, in an attempt to better understand response to ICI therapy; it also highlights the candidate markers for future research. The most promising biomarkers for response to ICI treatment are the occurrence of immune-related adverse events (especially vitiligo), lowering of lactate dehydrogenase, and increase in activated CD8 + and decrease in regulatory T-cells.

Biological Factors behind Melanoma Response to Immune Checkpoint Inhibitors

Modern immunotherapy together with targeted therapy has revolutionized the treatment of advanced melanoma. Inhibition of immune checkpoints significantly improved the median overall survival and gave hope to many melanoma patients. However, this treatment has three serious drawbacks: high cost, serious side effects, and an effectiveness limited only to approximately 50% of patients. Some patients do not derive any or short-term benefit from this treatment due to primary or secondary resistance. The response to immunotherapy depends on many factors that fall into three main categories: those associated with melanoma cells, those linked to a tumor and its microenvironment, and those classified as individual ontogenic and physiological features of the patient. The first category comprises expression of PD-L1 and HLA proteins on melanoma cells as well as genetic/genomic metrics such as mutational load, (de)activation of specific signaling pathways and epigenetic factors. The second category is the inflammatory status of the tumor: “hot” versus “cold” (i.e., high versus low infiltration of immune cells). The third category comprises metabolome and single nucleotide polymorphisms of specific genes. Here we present up-to-date data on those biological factors influencing melanoma response to immunotherapy with a special focus on signaling pathways regulating the complex process of anti-tumor immune response. We also discuss their potential predictive capacity.

T cell pathology in skin inflammation

Forming the outer body barrier, our skin is permanently exposed to pathogens and environmental hazards. Therefore, skin diseases are among the most common disorders. In many of them, the immune system plays a crucial pathogenetic role. For didactic and therapeutic reasons, classification of such immune-mediated skin diseases according to the underlying dominant immune mechanism rather than to their clinical manifestation appears to be reasonable. Immune-mediated skin diseases may be mediated mainly by T cells, by the humoral immune system, or by uncontrolled unspecific inflammation. According to the involved T cell subpopulation, T cell-mediated diseases may be further subdivided into T1 cell-dominated (e.g., vitiligo), T2 cell-dominated (e.g., acute atopic dermatitis), T17/T22 cell-dominated (e.g., psoriasis), and Treg cell-dominated (e.g., melanoma) responses. Moreover, T cell-dependent and -independent responses may occur simultaneously in selected diseases (e.g., hidradenitis suppurativa). The effector mechanisms of the respective T cell subpopulations determine the molecular changes in the local tissue cells, leading to specific microscopic and macroscopic skin alterations. In this article, we show how the increasing knowledge of the T cell biology has been comprehensively translated into the pathogenetic understanding of respective model skin diseases and, based thereon, has revolutionized their daily clinical management.

Complete Clinical Remission of Stage IV Triple-Negative Breast Cancer Lung Metastasis Administering Low-Dose Immune Checkpoint Blockade in Combination With Hyperthermia and Interleukin-2

The prognosis of triple-negative breast cancer with metastases after chemotherapy remains dismal. We report the case of a 50-year-old female with first disease recurrence at the axillary lymph node and, later on, bilateral pulmonary metastases with severe shortness of breath. The patient received low-dose immune checkpoint blockade (concurrent nivolumab and ipilimumab) weekly over 3 weeks with regional hyperthermia 3 times a week, followed by systemic fever-range hyperthermia induced by interleukin-2 for 5 days. She went into complete remission of her pulmonary metastases with transient WHO I-II diarrhea and skin rash. The patient remained alive for 27 months after the start of treatment, with recurrence of metastases as a sternal mass, and up to 3 cm pleural metastases. This exceptional response should instigate further research efforts with this protocol, which consists only of approved drugs and treatments.

Biomarkers for Immune Checkpoint Inhibitors in Melanoma

Immune checkpoint inhibitors have now become a standard therapy for malignant melanoma. However, as immunotherapies are effective in only a limited number of patients, biomarker development remains one of the most important clinical challenges. Biomarkers predicting clinical benefit facilitate appropriate selection of individualized treatments for patients and maximize clinical benefits. Many biomarkers derived from tumors and peripheral blood components have recently been reported, mainly in retrospective settings. This review summarizes the recent findings of biomarker studies for predicting the clinical benefits of immunotherapies in melanoma patients. Taking into account the complex interactions between the immune system and various cancers, it would be difficult for only one biomarker to predict clinical benefits in all patients. Many efforts to discover candidate biomarkers are currently ongoing. In the future, verification, by means of a prospective study, may allow some of these candidates to be combined into a scoring system based on bioinformatics technology.

Advances in Proteomic Techniques for Cytokine Analysis: Focus on Melanoma Research

Melanoma is a skin cancer with permanently increasing incidence and resistance to therapies in advanced stages. Reports of spontaneous regression and tumour infiltration with T-lymphocytes makes melanoma candidate for immunotherapies. Cytokines are key factors regulating immune response and intercellular communication in tumour microenvironment. Cytokines may be used in therapy of melanoma to modulate immune response. Cytokines also possess diagnostic and prognostic potential and cytokine production may reflect effects of immunotherapies. The purpose of this review is to give an overview of recent advances in proteomic techniques for the detection and quantification of cytokines in melanoma research. Approaches covered span from mass spectrometry to immunoassays for single molecule detection (ELISA, western blot), multiplex assays (chemiluminescent, bead-based (Luminex) and planar antibody arrays), ultrasensitive techniques (Singulex, Simoa, immuno-PCR, proximity ligation/extension assay, immunomagnetic reduction assay), to analyses of single cells producing cytokines (ELISpot, flow cytometry, mass cytometry and emerging techniques for single cell secretomics). Although this review is focused mainly on cancer and particularly melanoma, the discussed techniques are in general applicable to broad research field of biology and medicine, including stem cells, development, aging, immunology and intercellular communication.

NF-κB c-Rel Is Crucial for the Regulatory T Cell Immune Checkpoint in Cancer

Regulatory T cells (Tregs) play a pivotal role in the inhibition of anti-tumor immune responses. Understanding the mechanisms governing Treg homeostasis may therefore be important for development of effective tumor immunotherapy. We have recently demonstrated a key role for the canonical nuclear factor κB (NF-κB) subunits, p65 and c-Rel, in Treg identity and function. In this report, we show that NF-κB c-Rel ablation specifically impairs the generation and maintenance of the activated Treg (aTreg) subset, which is known to be enriched at sites of tumors. Using mouse models, we demonstrate that melanoma growth is drastically reduced in mice lacking c-Rel, but not p65, in Tregs. Moreover, chemical inhibition of c-Rel function delayed melanoma growth by impairing aTreg-mediated immunosuppression and potentiated the effects of anti-PD-1 immunotherapy. Our studies therefore establish inhibition of NF-κB c-Rel as a viable therapeutic approach for enhancing checkpoint-targeting immunotherapy protocols.

Empirical Modeling of Physiochemical Immune Response of Multilayer Zinc Oxide Nanomaterials under UV Exposure to Melanoma and Foreskin Fibroblasts

Carcinogenesis is a complex molecular process starting with genetic and epigenetic alterations, mutation stimulation, and DNA modification, which leads to proteomic adaptation ending with an uncontrolled proliferation mechanism. The current research focused on the empirical modelling of the physiological response of human melanoma cells (FM55P) and human foreskin fibroblasts cells (AG01518) to the multilayer zinc oxide (ZnO) nanomaterials under UV-A exposure. To validate this experimental scheme, multilayer ZnO nanomaterials were grown on a femtotip silver capillary and conjugated with protoporphyrin IX (PpIX). Furthermore, PpIX-conjugated ZnO nanomaterials grown on the probe were inserted into human melanoma (FM55P) and foreskin fibroblasts cells (AG01518) under UV-A light exposure. Interestingly, significant cell necrosis was observed because of a loss in mitochondrial membrane potential just after insertion of the femtotip tool. Intense reactive oxygen species (ROS) fluorescence was observed after exposure to the ZnO NWs conjugated with PpIX femtotip model under UV exposure. Results were verified by applying several experimental techniques, e.g., ROS detection, MTT assay, and fluorescence spectroscopy. The present work reports experimental modelling of cell necrosis in normal human skin as well as a cancerous tissue. These obtained results pave the way for a more rational strategy for biomedical and clinical applications.

Comparative investigation of the effects of specific antigen‑sensitized DC‑CIK and DC‑CTL cells against B16 melanoma tumor cells

The use of personalized adoptive immunotherapy as a potential novel approach is promising in the treatment of tumors resistant to conventional therapies. In the present study, dendritic cell (DC)-cytokine-induced killer (CIK) and DC-cytotoxic lymphocyte (CTL) cells were cultured to examine their phenotype, proliferation and cytotoxicity against B16 melanoma tumor cells. In addition, comparative investigations of the effect of specific antigen-sensitized DC-CIK and DC-CTL cells against B16 melanoma tumor cells were performed in vitro and in vivo. The results showed that the phenotypes of the co-cultured cells were altered, and DCs promoted DC-CIK cell and DC-CTL cell differentiation and maturation in vitro. Lactate dehydrogenase cytotoxic analysis indicated that the cytotoxicity increased as the effector to target ratio increased between 10:1 and 40:1, and the cytotoxic effect towards B16 melanoma cells by DC-CTL cells was significantly higher, compared with that of DC-CIK cells. To further examine the antineoplastic efficacy of DC-CIK and DC-CTL cells in vivo, the present study performed tail-intravenous injection of DC-CIK cells and DC-CTL cells, which attenuated B16 melanoma cell-engrafted tumor growth, induced G₀/G₁ cell cycle arrest and accelerated cell apoptosis. Taken together, these results suggested that the use of DC-CTL or DC-CIK cell therapy as a personalized adoptive immunotherapy may regulate immune status and inhibit tumor growth in vivo. In addition, the experiments indicated that DC-CTL cells offer superior antineoplastic activity, compared with DC-CIK cells against B16 melanoma tumor cells.

Five-year disease-free survival among stage II-IV breast cancer patients receiving FAC and AC chemotherapy in phase II clinical trials of Panagen

BACKGROUND

We report on the results of a phase II clinical trial of Panagen (tablet form of fragmented human DNA preparation) in breast cancer patients (placebo group n = 23, Panagen n = 57). Panagen was administered as an adjuvant leukoprotective agent in FAC and AC chemotherapy regimens. Pre-clinical studies clearly indicate that Panagen acts by activating dendritic cells and induces the development of adaptive anticancer immune response.

METHODS

We analyzed 5-year disease-free survival of patients recruited into the trial.

RESULTS

Five-year disease-free survival in the placebo group was 40 % (n = 15), compared with the Panagen arm - 53 % (n = 51). Among stage III patients, disease-free survival was 25 and 52 % for placebo (n = 8) and Panagen (n = 25) groups, respectively. Disease-free survival of patients with IIIB + C stage was as follows: placebo (n = 6)-17 % vs Panagen (n = 18)-50 %.

CONCLUSIONS

Disease-free survival rate (17 %) of patients with IIIB + C stage breast cancer receiving standard of care therapy is within the global range. Patients who additionally received Panagen demonstrate a significantly improved disease-free survival rate of 50 %. This confirms anticancer activity of Panagen.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02115984 from 04/07/2014.